TWI841887B - Photosensitive element, dry film photoresist, resist pattern, circuit board, and display device using the same - Google Patents

Abstract

The present disclosure relates to a photosensitive element comprising: a polymer substrate; and a photosensitive resin layer formed on the polymer substrate, wherein a thickness of a palladium plating layer, which is obtained by immersing a film sample in which the photosensitive resin layer is laminated on the substrate in a palladium plating solution for 60 minutes and then immersing a copper clad laminate sample in a residual palladium plating solution for 5 minutes, is 0.01 μm or more, and a dry film photoresist, a resist pattern, a circuit board, and a display device using the same.

Description

Photosensitive element, dry film photoresist, impedance pattern, circuit board, and display device using the same

The present disclosure relates to a photosensitive element, a dry film photoresist, an impedance pattern, a circuit board and a display device.

Photosensitive resin compositions are used in dry film photoresists (DFRs), liquid photoresists (liquid photoresist inks), etc. used in printed circuit boards (PCBs) or lead frames.

At present, dry film photoresist is not only widely used in the manufacture of printed circuit boards (PCBs) and lead frames, but also used in the manufacture of rib barriers for plasma display panels (PDPs), indium tin oxide (ITO) electrodes for other displays, bus address electrodes, and black matrices.

Typically, this type of dry film photoresist is often used in applications where it is laminated on a copper clad laminate. In this regard, as an example of a manufacturing process for a printed circuit board (PCB), a copper clad laminate sample is laminated as a raw board material for the PCB and a pretreatment step is first performed. In the outer layer process, the pretreatment step is performed in the order of drilling, deburring, scrubbing, etc., and scrubbing or pickling is performed in the inner layer process. In the scrubbing step, a bristle brush and pumice process are mainly used, and in the pickling step, soft etching and 5 wt% sulfuric acid pickling can be performed.

To form circuits on a copper-clad laminate that has undergone a pre-treatment step, a dry film photoresist (DFR) (hereinafter referred to as DFR) layer is usually laminated on the copper layer of the copper-clad laminate. In this step, the photoresist layer of DFR is laminated on the copper surface while the protective film of the DFR is peeled off using a laminating machine. Typically, lamination is performed at a speed of 0.5 meters per minute (m/min) to 3.5 meters per minute, a temperature of 100°C to 130°C, and a heated roller pressure of 10 pounds per square inch (psi) to 90 pounds per square inch.

The printed circuit board that has been through the lamination step is left to stand for 15 minutes or more to stabilize the board, and then exposed to the photoresist of the DFR using a photomask on which a desired circuit pattern is formed. When the photomask is irradiated with ultraviolet light in this process, the photoresist irradiated with ultraviolet light begins to polymerize with the contained photoinitiator at the irradiated portion. First, oxygen in the photoresist is consumed in the initial stage, and then the active monomer is polymerized to cause a crosslinking reaction. Subsequently, the polymerization reaction continues while consuming a large amount of monomers. On the other hand, the unexposed portion exists in a state where the crosslinking reaction has not yet been performed.

Next, a developing step of removing the unexposed portion of the photoresist is performed. In the case of an alkaline developable DFR, an aqueous solution of 0.8 wt % to 1.2 wt % potassium carbonate and sodium carbonate is used as a developing solution. In this step, the unexposed portion of the photoresist is washed away by a saponification reaction between the developing solution and the carboxylic acid of the binder polymer in the developing solution, and the cured photoresist remains on the copper surface.

Then, the circuit is formed by different steps according to the inner layer and outer layer processes. In the inner layer process, the circuit is formed on the substrate by etching and stripping steps, while in the outer layer process, plating and tenting steps are performed, and then etching and solder stripping are performed to form a predetermined circuit.

[Technical issues]

An object of the present disclosure is to provide a photosensitive element that can achieve the effect of reducing contamination of a plating solution and allowing plating to be performed with a sufficient thickness.

Another purpose of the present disclosure is to provide a dry film photoresist, an impedance pattern, a circuit board, and a display device using the above-mentioned photosensitive element. [Technical Solution]

To achieve the above-mentioned purpose, according to one aspect, a photosensitive element is provided, which comprises: a polymer substrate; and a photosensitive resin layer formed on the polymer substrate, wherein the thickness of the palladium-plated layer is 0.01 micrometer or greater, and the palladium-plated layer is obtained by immersing a film sample in which the photosensitive resin layer is stacked on the substrate in a palladium-plating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium-plating solution for 5 minutes.

According to another aspect, a dry film photoresist is provided, the dry film photoresist comprising: a photosensitive resin composition including an alkaline developable binder resin, a photopolymerization initiator and a photopolymerizable compound, wherein the photopolymerizable compound comprises at least one selected from the group consisting of a penta-type (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups, and wherein a palladium-plated layer obtained by immersing a film sample in which the photosensitive resin layers of the dry film photoresist are stacked on a substrate in a palladium-plating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium-plating solution for 5 minutes has a thickness of 0.01 μm or more.

According to another aspect, a dry film photoresist is provided, the dry film photoresist comprising: a photosensitive resin composition including an alkaline developable binder resin, a photopolymerization initiator and a photopolymerizable compound, wherein the alkaline developable binder resin comprises four or more polymers that are different from each other, and wherein the thickness of the palladium-plated layer obtained by immersing a film sample in which the photosensitive resin layers of the dry film photoresist are stacked on a substrate in a palladium-plating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium-plating solution for 5 minutes is 0.01 micrometers or more.

According to another aspect, a resistance pattern is provided, the resistance pattern including a photosensitive resin pattern containing the photosensitive resin composition contained in the dry film photoresist.

According to another aspect, a circuit board is provided, the circuit board including the impedance pattern or a metal pattern formed by the impedance pattern.

According to another aspect, a display device is provided, the display device including the impedance pattern or a metal pattern formed by the impedance pattern.

Now, a photosensitive element, a dry film photoresist, a resistance pattern, a circuit board and a display device according to a specific embodiment of the present disclosure are described in more detail.

Unless otherwise described in detail throughout this specification, the technical terms used herein are only used to refer to specific embodiments and are not intended to limit the present disclosure.

As used herein, the singular forms "a," "an," and "the" include plural references as well, unless the context clearly indicates otherwise.

The terms “including” or “comprising” used herein specify specific features, regions, integers, steps, actions, elements and/or components, but do not exclude the existence or addition of different specific features, regions, integers, steps, actions, elements, components and/or groups.

In addition, terms including ordinal numbers such as "first", "second", etc. are only used for the purpose of distinguishing each component and are not limited to the ordinal numbers. For example, a first component may be referred to as a second component, or similarly, a second component may be referred to as a first component without departing from the scope of the present disclosure.

In the present disclosure, examples of substituents are described below, but are not limited thereto.

In the present disclosure, the term "substituted" means that other functional groups are bonded to the hydrogen atom in the compound instead of each other, and the position to be substituted is not limited, as long as the position is the position where the hydrogen atom is substituted (i.e., the position where the substituent can be substituted), and when two or more substituents are substituted, the two or more substituents may be the same or different from each other.

In the present disclosure, the term "substituted or unsubstituted" means unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, halogen, cyano, nitro, hydroxyl, carbonyl, ester, imide, amide, primary amino, carboxyl, sulfonic acid, sulfonamido, phosphine oxide, alkoxy, aryloxy, alkylthiooxy, arylthiooxy, alkylsulfonyloxy, arylsulfonyloxy, silyl, boron, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, aralkenyl, alkylaryl, alkoxysilylalkyl, arylphosphino, or heterocyclic group containing at least one of N, O and S atoms, or unsubstituted or substituted with substituents linked to two or more substituents among the substituents exemplified above. For example, a "substituent group linked to two or more substituent groups" may be a biphenyl group. That is, the biphenyl group may also be an aryl group, and can be interpreted as a substituent group linked to two phenyl groups.

In this disclosure, the symbol or It means a bond to another substituent, and a direct bond means the case where other atoms are not present in the portion represented as L.

In the present disclosure, (meth)acrylic acid is intended to include both acrylic acid and methacrylic acid. For example, (meth)acrylic acid may include both acryl and methacrylic acid. In addition, (meth)acrylate may include both acrylate and methacrylate.

In the present disclosure, an alkyl group is a monovalent functional group derived from an alkane and may be a linear or branched chain. The number of carbon atoms in a linear alkyl group is not particularly limited, but is preferably 1 to 20. In addition, the number of carbon atoms in a branched chain alkyl group is 3 to 20. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, t-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, t-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, octyl, n-octyl, t-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethylpropyl, 1,1-dimethylpropyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, 2,6-dimethylheptan-4-yl and the like, but are not limited thereto. The alkyl group may be substituted or unsubstituted, and when it is substituted, examples of the substituent are the same as those described above.

In the present disclosure, an aryl group is a monovalent functional group derived from an aromatic hydrocarbon, and is not particularly limited, but preferably has 6 to 20 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. Specific examples of monocyclic aryl groups may include phenyl, biphenyl, terphenyl, and the like, but are not limited thereto. Specific examples of polycyclic aryl groups may include naphthyl, anthracenyl, phenanthrenyl, pyrenyl, perylenyl, chrysene, fluorenyl, and the like, but are not limited thereto. The aryl group may be substituted or unsubstituted, and when it is substituted, examples of the substituents are the same as those described above.

The present disclosure will be described in more detail below. 1. Photosensitive element

According to an embodiment of the present disclosure, a photosensitive element can be provided, comprising: a polymer substrate; and a photosensitive resin layer formed on the polymer substrate, wherein the thickness of the palladium-plated layer is 0.01 micrometer or greater, and the palladium-plated layer is obtained by immersing a film sample in which the photosensitive resin layers are stacked on the substrate in a palladium-plating solution for 60 minutes and then immersing a copper-coated stacked board sample in the residual palladium-plating solution for 5 minutes.

Various plastic films may be used as the substrate film, and examples thereof may include at least one plastic film selected from the group consisting of an acrylic film, a polyethylene terephthalate (PET) film, a triacetylcellulose (TAC) film, a polynorbornene (PNB) film, a cycloolefin polymer (COP) film, and a polycarbonate (PC) film. The thickness of the substrate film is not particularly limited, and, for example, it may be freely adjusted within a range of 0.01 μm to 1 mm.

A specific example of the polymer substrate may be a polyester film in which an anti-blocking layer is formed by an in-line coating method of uniaxially stretching an unstretched polyester film, applying a coating solution containing a binder resin and organic particles onto one surface thereof, and uniaxially stretching the remaining portion.

The polymer substrate is typically fabricated by an in-line coating process, rather than adding anti-blocking agents (which are typically added due to runnability and winding characteristics concerns during manufacturing), and has an organic particle layer using alternative particles that do not compromise transparency.

Here, examples of organic particles used as particles that do not impair transparency while taking into account the running property and winding characteristics may include, for example, acrylic particles in which, for example, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, n-butyl methyl methacrylate, acrylic acid, methacrylic acid copolymers or terpolymers are formed; olefin particles (e.g., polyethylene, polystyrene, or polypropylene); acrylic and olefin copolymers; or homopolymer particles and then another type of monomer is coated on the layer. Multi-layer multi-component particles.

Such organic particles should specifically have a refractive index different from that of the binder resin while being spherical. Here, "spherical" means that the ratio of the short axis (a) to the long axis (b) in the ellipse is 0.5 < a/b < 2, and the relationship with the diagonal (d) in the rectangle is defined by d2≤a2+b2. Furthermore, the relationship between the axis (f) with the longest distance between the vertices in the hexahedron and the c axis other than the a axis and the b axis is defined by f2≤c2+a2+b2. The shape of the particles should be spherical, which is better in terms of material flowability.

And, it is characterized in that the refractive index difference between the organic particles and the binder resin is 0.05 or less. When the refractive index difference is greater than 0.05, the haze increases. This means that there is a large amount of scattered light, and when there is a large amount of such scattered light, the sidewall smoothing effect is reduced. This also depends on the size and amount of the organic particles. It is preferred that the organic particles have an average particle size of about 0.5 microns to 5 microns. When it is less than this value, the material running and winding characteristics deteriorate, and when it is greater than 5 microns, the haze increases, and there is concern about the occurrence of falling problems, which is not preferred. The content of the organic particles is preferably 1% by weight to 10% by weight based on the total amount of the binder resin.

When the content of the organic particles is less than 1 wt % based on the total amount of the binder resin, the anti-blocking effect is insufficient and the film is easily scratched, and the material flow and winding characteristics are deteriorated, and when it exceeds 10 wt %, there may be a problem of increased haze and deteriorated transparency properties.

Meanwhile, in addition to the above organic particles, inorganic particles may also be added. At this time, it is not preferred to add a commonly used inorganic anti-adhesion agent, and it is preferred to add colloidal silica having a particle size of 100 nanometers or less. The content thereof is preferably 10 parts by weight or less based on 100 parts by weight of the adhesive resin. When the particle size and content as described above are met, the appearance of side wall defects or grooves (such as pits) caused by the anti-adhesion layer when forming a pattern using a dry film photoresist can be prevented.

As the binder resin serving as a binder for coating such organic particles on the unstretched polyester film, a binder resin having excellent compatibility with the organic particles can be used. Examples of such resins may include: acrylic resins such as unsaturated polyester, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, n-butyl methyl methacrylate, acrylic acid, methacrylic acid copolymers or terpolymers; urethane resins; epoxy resins; or melamine resins and the like, and acrylic resins are preferred.

The solvent that can be used to prepare the coating solution using the binder resin and the organic particles is preferably water.

As described above, an unstretched polyester film obtained by melt extruding PET pellets is uniaxially stretched, and then a coating solution containing organic particles in a binder resin is coated on the uniaxially stretched film. The coating can be performed on at least one side of the uniaxially stretched film, and the thickness is preferably about 30 nm to 200 nm in terms of thickness after final drying. If the coating solution containing organic particles is coated on the uniaxially stretched film to a thickness of more than 30 nm, there are problems that the organic particles are easily dropped and scratched, and white powder is generated. When coating is thicker than 200 nm, coating streaks are generated in the coating direction in in-line coating with high coating speeds due to the increased viscosity of the coating solution.

The polymer substrate obtained by coating with organic particles different from the general anti-blocking agent by the above-mentioned on-line coating method is a substrate film having excellent transportability and winding characteristics due to the particle layer and excellent light transmission due to the excellent light transmission of the organic particles.

Since lamination of the photosensitive resin layer is performed on the opposite surface of the layer containing organic particles in the polymer substrate, the photosensitive resin layer is formed on the opposite surface of the layer containing organic particles in this manner. Therefore, when the substrate film including the anti-adhesive agent is laminated as before, pit-shaped defects do not occur. Since particles such as silicon dioxide are not only larger in size than organic particles but also distributed over the entire substrate film, the influence of silicon dioxide is negligible even in the region adjacent to the photosensitive resin layer.

On the other hand, in the polymer substrate used in the present disclosure, the organic particles have a size of 0.5 micrometers to 5 micrometers, and the organic particle layer is not adjacent to the photosensitive resin layer so that the physical effect of the organic particles is not affected. In addition, by using organic particles with excellent light transmittance, side wall defects can be reduced without compromising other circuit properties.

The photosensitive element may further include a protective film formed on the photosensitive resin layer. The protective film prevents the photosensitive resin layer from being damaged during handling, and functions as a protective covering to protect the photosensitive resin layer from foreign matter (e.g., dust). The protective film layer is superimposed on the back side of the photosensitive resin layer where the polymer substrate is not formed. The protective film is used to protect the photosensitive resin layer from external influences. When the dry film photoresist is applied for post-processing, it needs to be easily detached, and it needs appropriate releasability and adhesion to allow it to be deformed during storage and distribution.

Various plastic films may be used as the protective film, and examples thereof may include at least one plastic film selected from the group consisting of an acrylic film, a polyethylene (PE) film, a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, a polynorbornene (PNB) film, a cycloolefin polymer (COP) film, and a polycarbonate (PC) film. The thickness of the protective film is not particularly limited, and, for example, it may be freely adjusted within a range of 0.01 μm to 1 mm.

The photosensitive element has a characteristic that the thickness of the palladium plating layer may be 0.01 micron or more, or 0.05 micron or more, or 0.1 micron or more, or 0.01 micron or more and 0.15 micron or less, or 0.05 micron or less, or 0.15 micron or less, or 0.1 micron or more and 0.15 micron or less, and the palladium plating layer is obtained by immersing a film sample in which a photosensitive resin layer is stacked on a substrate in a palladium plating solution for 60 minutes and then immersing a copper-coated laminate sample in the residual palladium plating solution for 5 minutes.

In addition, the photosensitive element has a characteristic that the thickness of the nickel-phosphorus plated layer may be 3.9 microns or more, or 3.95 microns or more, or 3.9 microns or more and 4.0 microns or less, or 3.95 microns or more and 4.0 microns or less, and the nickel-phosphorus plated layer is obtained by immersing a film sample in which a photosensitive resin is stacked on a substrate for 38 minutes and then immersing a copper-coated laminated board sample in the residual nickel-phosphorus plated solution for 28 minutes, or as Alternatively, the dry film photoresist may have a gold-plated layer having a thickness of 0.11 μm or more, or 0.11 μm or more and 0.13 μm or less, or 0.12 μm or more, or 0.12 μm or more and 0.13 μm or less, the gold-plated layer being obtained by immersing a film sample in which a photosensitive resin layer is stacked on a substrate in a gold-plating solution for 98 minutes and then immersing a copper-clad laminate sample in the residual gold-plating solution for 11 minutes.

The residual palladium plating solution is a palladium plating solution contaminated by a component of a photosensitive resin layer, and the thickness of the palladium plating layer obtained by immersing a copper-clad laminate sample in the contaminated residual palladium plating solution for 5 minutes is used to evaluate the nature of the plating solution contamination by a dry film photoresist when palladium is plated on a laminate with a photosensitive resin layer laminated thereon. As the contamination of the plating solution becomes more serious, the thickness of the palladium plating layer obtained by immersing the copper-clad laminate sample in the palladium plating solution for 5 minutes becomes significantly lower. On the other hand, as the plating solution is less contaminated, the thickness of the palladium-plated layer obtained by immersing the copper-clad laminate sample in the contaminated palladium plating solution for 5 minutes becomes significantly higher. Therefore, during the actual electroless palladium plating process, the contaminants accumulate in the bulk dry film resist, and only palladium is added for continuous plating, which makes other cleaning treatments difficult. Therefore, it is extremely important to evaluate the extent to which the palladium plating solution is contaminated by the dry film resist.

That is, in palladium plating, first, a first palladium plating using a film on which a photosensitive resin layer is laminated is performed. After the first plating has been completed, a second palladium plating is performed on a new copper-clad laminate sample in a contaminated palladium plating solution, and the nature of the plating solution being contaminated by the dry film photoresist is evaluated with respect to the thickness of the palladium plating layer at the second plating.

Therefore, the thickness of the palladium coating obtained by immersing the film sample in which the photoresist layer is stacked on the substrate in the palladium coating solution for 60 minutes and then immersing the copper-clad laminate sample in the residual palladium coating solution for 5 minutes is excessively reduced to less than 0.1 micrometers as a target value, and the contamination degree of the coating solution can be evaluated accordingly. When evaluating the contamination degree, when the coating layer is plated to a thickness lower than the target value, the contamination of the electroless palladium coating solution is serious in the actual process, and therefore, it is difficult to reuse the coating solution for more than 0.5 metal turn over (MTO), which may be disadvantageous in terms of process efficiency and economy.

The method of calculating the thickness of the palladium coating layer is not particularly limited, and various known methods for measuring the thickness of the coating layer can be applied without limitation. For example, the measurement can be performed by an XRF coating thickness measuring instrument (Helmut Fischer XDV-μ).

A more specific example of a method of obtaining a residual palladium plating solution after immersing a film sample in which a photosensitive resin is layered on a substrate in the palladium plating solution for 60 minutes is described below.

First, the copper-clad laminate sample with the photosensitive resin layer stacked thereon may be immersed in a nickel-phosphorus solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the photosensitive resin layer stacked thereon in the nickel-phosphorus solution are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 660 square centimeters or less may be immersed in a nickel-phosphorus solution at 65°C or more and 95°C or less. A sample of 0 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of NPR-4 (Uemura) plating solution (as a nickel-phosphorus-containing plating solution) for 20 minutes or more and 60 minutes or less to perform elution. The cross-sectional area refers to the area of a cross section obtained by cutting the sample in a direction perpendicular to the direction in which the thickness of the sample increases.

If necessary, the sample may be immersed in a catalyst aqueous solution before being immersed in the nickel-phosphorus plating solution, and the specific conditions are not particularly limited. For example, a copper-clad laminate sample in which photosensitive water layers are stacked on a substrate may be immersed for 30 seconds to 90 seconds under the conditions of 10° C. or more and 40° C. or less by using CATA NC-20 (MK Chem & Tech) as a palladium-plating catalyst solution.

Next, the copper-clad laminate sample with the nickel-plated photosensitive resin layer stacked thereon may be immersed in a palladium plating solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the nickel-plated photosensitive resin layer stacked thereon are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 700 square centimeters or less, may be immersed in a palladium plating solution at 30°C or more and 70°C or less. A sample of 660 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of TPD-21 (Uemura) coating solution (as a palladium coating solution) for 30 minutes or more and 90 minutes or less to perform elution.

At the same time, the copper-clad laminate sample with the palladium-plated photosensitive resin layer stacked thereon may be immersed in the gold plating solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the palladium-plated photosensitive resin layer thereon are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 640 square centimeters or less may be immersed in the gold plating solution at 65°C or more and 95°C or less. A sample of 60 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of TMX-40 (Uemura) plating solution (as a gold plating solution) for 50 minutes or more and 150 minutes or less to perform elution.

Meanwhile, a more specific example of a method for measuring the thickness of a palladium-plated layer obtained by immersing a copper-clad laminate sample in a residual palladium-plating solution for 5 minutes is described below.

First, the copper-clad laminate sample can be immersed in the residual nickel-phosphorus solution. Although the specific conditions for immersing the copper-clad laminate sample in the residual nickel-phosphorus plating solution are not particularly limited, for example, under the conditions of 65°C or more and 95°C or less, a copper-clad laminate sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters is immersed in 130 ml of the residual NPR-4 (Uemura) plating solution and plated for 15 minutes or more and 45 minutes or less. The cross-sectional area is the area of the cross section obtained by cutting the sample in a direction perpendicular to the direction in which the thickness of the sample increases.

If necessary, the sample may be immersed in a catalyst aqueous solution before being immersed in the nickel-phosphorus plating solution. Although the specific conditions are not particularly limited, for example, the sample may be immersed for 90 seconds under the conditions of 10°C or more and 40°C or less by using CATA NC-20 (MK Chemical & Technology Co., Ltd.) as a palladium catalyst.

When the thickness of the palladium coating layer is measured, exposure may be performed by irradiating ultraviolet light using an exposure machine at an exposure dose of 20 mJ/ ^cm2 or more and 200 mJ/cm2 or less, or 50 mJ/cm2 or more and 100 mJ/cm2 or less. The exposure time may be 1 second or more and 10 minutes or less, or 1 second or more and 10 seconds or less.

When measuring the thickness of the palladium-plated layer, development may be performed by using an alkaline aqueous solution having a concentration of 0.5 wt % or more and 1.5 wt % or less, or 0.9 wt % or more and 1.1 wt % or less. The pH of the alkaline aqueous solution may be in the range of 9 or more and 11 or less, and the temperature may be adjusted in accordance with the developability of the photosensitive resin layer. Specific examples of the alkaline aqueous solution include a sodium carbonate aqueous solution, a potassium carbonate aqueous solution, a sodium hydroxide aqueous solution, and the like.

The development can be performed by a method of bringing an alkaline aqueous solution into contact with the photosensitive resin layer. As specific examples of the contact method, a spray spraying method or an immersion method can be used. The development time can be 30 seconds or more and 10 minutes or less, or 30 seconds or more and 2 minutes or less.

At this time, the photosensitive element has a characteristic that the thickness of the nickel-phosphorus plated layer may be 3.9 μm or more, or 3.95 μm or more, or 3.9 μm or more and 4.0 μm or less, or 3.95 μm or more and 4.0 μm or less, and the nickel-phosphorus plated layer is obtained by immersing a film sample in which a photosensitive resin layer is stacked on a substrate in a nickel-phosphorus plated solution for 38 minutes and then immersing a copper-clad laminate sample in the remaining nickel-phosphorus plated solution for 28 minutes.

Next, the nickel-coated copper laminate samples can be immersed in the residual palladium plating solution to perform the coating. Although the specific conditions for immersing the nickel-phosphorus plated copper-coated laminate sample in the residual palladium plating solution are not particularly limited, for example, the plating can be performed by immersing a sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters in 130 ml of the residual TPD-21 (Uemura) plating solution for 2 minutes or more and 10 minutes or less at 30°C or more and 70°C or less.

At the same time, the palladium-plated copper-clad laminate samples can be immersed in the residual gold plating solution to perform plating. Although the specific conditions for immersing the palladium-plated copper-clad laminate sample in the residual gold plating solution are not particularly limited, for example, the plating can be performed by immersing a sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters in 130 ml of the residual TWX-40 (Uemura) plating solution for 5 minutes or more and 20 minutes or less at 65°C or more and 95°C or less.

At this time, the photosensitive element has a characteristic that the thickness of the gold-plated layer may be 0.11 μm or greater, or 0.11 μm or greater and 0.13 μm or less, or 0.12 μm or greater, or 0.12 μm or greater and 0.13 μm or less, and the gold-plated layer is obtained by immersing a film sample in which a photosensitive resin layer is stacked on a substrate in a gold-plating solution for 98 minutes and then immersing a copper-clad laminate sample in the residual gold-plating solution for 11 minutes.

Meanwhile, the film sample in which the photosensitive resin is laminated on the substrate may be a laminate in which the photosensitive resin is laminated on any substrate. An example of the substrate may be a copper-clad laminate in which a copper layer having a thickness of 10 μm or more and 100 mm or less is provided on the surface.

The cross-sectional area of the film sample in which the photosensitive resin layers are stacked on the substrate may be 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 660 square centimeters or less, or 645 square centimeters or more and 655 square centimeters or less.

In addition, the cross-sectional area of the copper-clad laminate sample used for immersing the copper-clad laminate sample in the residual palladium plating solution for 5 minutes may be 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less.

The photosensitive resin layer may contain an alkaline developable binder resin.

The photosensitive resin layer may include a dried product or a cured product of the photosensitive resin composition. The dried product refers to a material obtained by a drying step of the photosensitive resin composition. The cured product refers to a material obtained by a curing step of the photosensitive resin composition. The thickness of the photosensitive resin layer is not particularly limited, but, for example, it can be freely adjusted within a range of 0.01 micrometers to 1 millimeter.

The photosensitive resin layer contains a photosensitive resin composition, which includes an alkaline developable adhesive resin, a photopolymerization initiator and a photopolymerizable compound, wherein the photopolymerizable compound includes at least one selected from the group consisting of a pentatype (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups.

The inventors have experimentally confirmed that the photosensitive resin composition contains a penta-type (meth)acrylate compound having five (meth)acryl groups, a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups, or a mixture of two or more thereof as a photopolymerizable compound, thereby achieving the effect of reducing contamination of metal plating solutions such as palladium plating solutions or nickel-phosphorus plating solutions and allowing plating to be performed with sufficient thickness, and completing the present disclosure.

The alkaline developable binder resin may include a repeating unit represented by the following chemical formula E, a repeating unit represented by the following chemical formula F, a repeating unit represented by the following chemical formula G, and a repeating unit represented by the following chemical formula H. [Chemical Formula E] Wherein, in Chemical Formula E, _R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, _R2 is an alkylene group having 1 to 10 carbon atoms, Ar is an aryl group having 6 to 20 carbon atoms, and n is an integer from 1 to 20, [Chemical Formula F] Wherein, in Chemical Formula F, R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms, [Chemical Formula G] Wherein, in Chemical Formula G, _R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and _R5 is an alkyl group having 1 to 10 carbon atoms, and [Chemical Formula H] Wherein, in the chemical formula H, Ar is an aromatic group having 6 to 20 carbon atoms.

Specifically, the alkali developable binder resin may include a random copolymer having a repeating unit represented by Chemical Formula E, a repeating unit represented by Chemical Formula F, a repeating unit represented by Chemical Formula G, and a repeating unit represented by Chemical Formula H.

Since the repeating unit represented by the chemical formula E is contained in the alkali developable binder resin to thereby increase the degree of hydrophobicity of the alkali developable binder resin through the benzene structure contained in the repeating unit represented by the chemical formula E, it suppresses the generation of foam in the development process of the dry film resist using the photosensitive resin composition and thus exhibits excellent developing properties, and can improve substrate adhesion and thus ensure appropriate physical properties (resolution, fine line adhesion, etc.).

In Chemical Formula E, R ₁ may be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms may include a methyl group.

In Chemical Formula E, R ₂ is an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms may include an ethyl group.

In Chemical Formula E, Ar is an aryl group having 6 to 20 carbon atoms, and a specific example of the aryl group having 6 to 20 carbon atoms may be a phenyl group.

The repeating unit represented by Chemical Formula E may be a repeating unit derived from a monomer represented by the following Chemical Formula E-1. [Chemical Formula E-1] Wherein, in Formula E-1, _R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, _R2 is an alkyl group having 1 to 10 carbon atoms, Ar is an aryl group having 6 to 20 carbon atoms, and n is an integer from 1 to 20. In Formula E-1, _R1 , _R2 , Ar and n have the same definitions as those described for Formula E.

Specific examples of the monomer represented by Chemical Formula E-1 may include phenoxypolyethyleneoxyacrylate, more specifically 2-phenoxyethyl methacrylate (PHEMA).

The content of the repeating unit represented by the chemical formula E may be 5 mol% or more and 40 mol% or less, or 5 mol% or more and 30 mol% or less, or 5 mol% or more and 25 mol% or less, or 10 mol% or more and 25 mol% or less, based on 100 mol% of all repeating units contained in the alkaline developable binder resin.

In Formulae F to H, R ₃ and R ₄ are the same as or different from each other and are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms, R ₅ is an alkyl group having 1 to 10 carbon atoms, and Ar is an aryl group having 6 to 20 carbon atoms.

In Chemical Formulae F to H, R ₃ and R ₄ are the same as or different from each other and may each independently be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms may include a methyl group.

R ₅ is an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms may include a methyl group.

Ar is an aryl group having 6 to 20 carbon atoms, and specific examples of the aryl group having 6 to 20 carbon atoms may include a phenyl group.

The repeating unit represented by the chemical formula F may be a repeating unit derived from a monomer represented by the following chemical formula F-1. [Chemical formula F-1] Wherein, in Chemical Formula F-1, R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms. In Chemical Formula F-1, R ₃ has the same definition as described above for Chemical Formula F. Specific examples of the monomer represented by Chemical Formula F-1 may include methacrylic acid (MAA).

The repeating unit represented by the chemical formula G may be a repeating unit derived from a monomer represented by the following chemical formula G-1. [Chemical formula G-1] Wherein, in Chemical Formula G-1, _R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and _R5 is an alkyl group having 1 to 10 carbon atoms. In Chemical Formula G-1, _R4 and _R5 have the same definitions as those described above for Chemical Formula G. Specific examples of the monomer represented by Chemical Formula G-1 may include methyl methacrylate (MMA).

The repeating unit represented by Chemical Formula H may include repeating units derived from a monomer represented by the following Chemical Formula H-1. [Chemical Formula H-1] Wherein, in Chemical Formula H-1, Ar is an aromatic group having 6 to 20 carbon atoms. In Chemical Formula H-1, the definition of Ar is the same as that described above for Chemical Formula H. Specific examples of the monomer represented by Chemical Formula H-1 may include styrene (SM).

The alkali-developable binder resin may contain 20 mol% or more and 60 mol% or less, or 20 mol% or more and 50 mol% or less, or 30 mol% or more and 40 mol% or less of the repeating unit represented by the chemical formula F, based on 100 mol% of all repeating units contained in the alkali-developable binder resin.

In addition, the alkaline developable adhesive resin may contain 1 mol% or more and 30 mol% or less, or 5 mol% or more and 30 mol% or less, of the repeating unit represented by the chemical formula G, and 30 mol% or more and 60 mol% or less, or 30 mol% or more and 50 mol% or less, or 30 mol% or more and 40 mol% or less, of the repeating unit represented by the chemical formula H, based on 100 mol% of all repeating units contained in the alkaline developable adhesive resin.

More specifically, the molar ratio of the repeating unit represented by the chemical formula G relative to 100 moles of the repeating unit represented by the chemical formula H may be 10 moles or more and 99 moles or less, or 15 moles or more and 95 moles or less, or 20 moles or more and 95 moles or less.

Thus, as the content of the hydrophobic repeating unit represented by the chemical formula H increases, the hydrophobicity of the alkaline developable binder resin also increases, thereby being able to suppress the generation of foam in the development process of the dry film photoresist using the photosensitive resin composition.

In addition, the molar ratio of the repeating unit represented by the chemical formula G relative to 100 moles of the repeating unit represented by the chemical formula E may be 16 moles or less, or 15.5 moles or less, or 15 moles or less, or 0.1 moles or more and 16 moles or less, or 0.1 moles or more and 5.5 moles or less, or 0.1 moles or more and 15 moles or less, or 10 moles or more and 16 moles or less, or 10 moles or more and 15.5 moles or less, or 10 moles or more and 15 moles or less.

The alkaline developable binder resin may have a weight average molecular weight of 30,000 g/mol or more and 150,000 g/mol or less, and a glass transition temperature of 20° C. or more and 150° C. or less. This can improve the coating property and followability of the dry film photoresist, and the mechanical strength of the resist itself after circuit formation.

The weight average molecular weight used herein refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). In the process of measuring the weight average molecular weight in terms of polystyrene measured by GPC, a detector and an analysis column such as a well-known analysis device and a differential refractive index detector can be used, and generally used temperature conditions, solvents, and flow rates can be used.

A specific example of the measurement conditions is as follows: an alkali developable binder resin is dissolved in tetrahydrofuran so that its concentration in THF is 1.0 (w/w) % (about 0.5 (w/w) % in terms of solid content), filtered using a syringe filter having a pore size of 0.45 μm, and then injected into a GPC in an amount of 20 μl, using tetrahydrofuran (THF) as a mobile phase of the GPC, and a flow rate of 1.0 mL/min. The column consisted of an Agilent Plagal 5 μm guard column (7.5 mm×50 mm) and two Agilent Plagal 5 μm mixed D columns (7.5 mm×300 mm) connected in series, and the measurement was performed at 40° C. by an RI detector using an Agilent 1260 Infinity II system as a detector.

Polystyrene standard samples (STD A, B, C, D) in which polystyrene having various molecular weights as described below was dissolved in tetrahydrofuran at a concentration of 0.1 (w/w)% were filtered through a syringe filter having a pore size of 0.45 μm and then injected into the GPC, and the weight average molecular weight (Mw) value of the alkaline developable binder resin was determined using a calibration curve. STD A (Mp): 791,000 / 27,810 / 945 STD B (Mp): 282,000 / 10,700 / 580 STD C (Mp): 126,000 / 4,430 / 370 STD D (Mp): 51,200 / 1,920 / 162

The glass transition temperatures of the reference polymer and the binder polymer were compared by a differential scanning calorimeter (DSC) (Perkin-Elmer, DSC-7). The measurement was performed by keeping the temperature at 20°C for 15 minutes and then increasing the temperature to 200°C at a rate of 1°C/min.

The acid value of the alkaline developable binder resin may be 120 mgKOH/g or more and 200 mgKOH/g or less, or 140 mgKOH/g or more and 160 mgKOH/g or less. The acid value is measured by the following process: in the process, about 1 g of the alkaline developable binder resin is sampled, dissolved in 50 ml of a mixed solvent (MeOH 20%, acetone 80%) to which two drops of 1% phenolphthalein indicator are added, and then titrated with 0.1N-KOH to measure the acid value.

Based on the solid content, the content of the alkaline developable binder resin is 20 wt % or more and 80 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the alkaline developable binder resin is within the above range, the effect of enhancing the adhesion of fine lines after circuit formation can be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition except the solvent.

Based on the solid content, the content of the alkaline developable binder resin is 20 wt % or more and 80 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the alkaline developable binder resin is within the above range, the effect of enhancing the adhesion of fine lines after circuit formation can be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition except the solvent.

The content of the alkaline developable binder resin may be 40 wt % or more and 70 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the alkaline developable binder resin is less than 40 wt % relative to the total photosensitive resin composition, there is a disadvantage of causing defects such as short circuits due to contamination in development, and when the content of the alkaline developable binder resin exceeds 70 wt %, there is a problem of deterioration of circuit properties such as adhesion and resolution.

The photopolymerization initiator contained in the photosensitive resin composition is a material that initiates the chain reaction of photopolymerizable monomers by ultraviolet (UV) and other radiation, and plays an important role in curing dry film photoresist.

Compounds that may be used as photopolymerization initiators may include anthraquinone derivatives such as 2-methylanthraquinone and 2-ethylanthraquinone, and benzoin derivatives such as benzoin methyl ether, benzophenone, phenanthrenequinone, and 4,4′-bis-(dimethylamino)benzophenone.

In addition, selected from 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-[4-morpholinophenyl]butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzyldiphenylphosphine oxide, 1-[4-(2-hydroxymethoxy)phenyl]-2-morpholinopropan-1-one, [(4-(2-((4-( ... Methyl ester, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-isoamyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyl ketone dimethyl acetal, benzyl ketone β-methoxydiethyl acetal, 1-phenyl-1,2-propanedioxime-o,o'-(2-carbonyl)ethoxy ether, methyl o-benzoylbenzoate, bis[4-dimethylaminophenyl]ketone, 4,4'-bis(diethylamino)benzophenone, 4,4'-dichlorobenzophenone The photopolymerization initiator may be a compound selected from the group consisting of benzyl, benzoin, methoxybenzoin, ethoxybenzoin, isopropoxybenzoin, n-butoxybenzoin, isobutoxybenzoin, tert-butoxybenzoin, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thiothionone, 2-methylthiothionone, 2-isopropylthiothionone, dibenzosuberone, α,α-dichloro-4-phenoxyacetophenone and 4-dimethylaminobenzoic acid amyl ester, but is not limited thereto.

Based on the solid content, the content of the photopolymerization initiator is 1 wt % or more and 10 wt % or less relative to the total weight of the photosensitive resin composition.

When the content of the photopolymerization initiator is within the above range, sufficient sensitivity can be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition except the solvent.

When the content of the photopolymerization initiator is less than 1 wt %, the light efficiency is low and a large amount of exposure must be applied, and therefore, there is a disadvantage that the production efficiency is greatly reduced. When the content of the photopolymerization initiator exceeds 10 wt %, there are problems that the film is fragile and the contamination of the developing solution increases, resulting in defects such as short circuits.

The photopolymerizable compound disclosed herein is resistant to developing solutions after UV exposure and is capable of forming patterns.

The photopolymerizable compound may include at least one selected from the group consisting of a penta-type (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups.

That is, the photopolymerizable compound may include a type of penta-type (meth)acrylate compound having five (meth)acryl groups, a type of multifunctional (meth)acrylate compound having seven or more (meth)acryl groups, or a mixture of two or more thereof.

Since the photopolymerizable compound of one embodiment includes at least one selected from the group consisting of a penta-type (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups, it is possible to achieve the effect of reducing contamination of a metal plating solution such as a palladium plating solution or a nickel-phosphorus plating solution and allowing plating to be performed with a sufficient thickness.

The weight ratio of the penta-type (meth)acrylate compound having five (meth)acryl groups to the multifunctional (meth)acrylate compound having seven or more (meth)acryl groups may be 99:1 to 1:99.

The five-type (meth)acrylate compound having five (meth)acryloyl groups may have five (meth)acryloyl groups. Each of the five (meth)acryloyl groups may be the same as or different from each other. The five-type (meth)acrylate compound may include all (meth)acrylate compounds having five (meth)acryloyl groups or derivatives thereof.

The five-type (meth)acrylate compound may further include a hydroxyl group. Specifically, the five-type (meth)acrylate compound may be a compound represented by the following chemical formula A. [Chemical formula A] Wherein, in Chemical Formula A, five of _T1 to _T6 are the same or different from each other and are each independently a (meth)acryloyl group, and the remaining one is hydrogen. More specifically, in Chemical Formula 1, _T1 to _T5 may be an acryl group, and _T6 may be hydrogen.

Specific examples of the compound represented by Chemical Formula A may include M500 (dipentaerythritol pentaacrylate, Mw 524, Miwon Specialty Chemical).

The multifunctional (meth)acrylate compound having seven or more (meth)acryloyl groups may have seven or more, or seven or more and 20 or less, or seven or more and 10 or less (meth)acryloyl groups. Each of the seven or more (meth)acryloyl groups may be the same or different from each other. The multifunctional (meth)acrylate compound includes all (meth)acrylate compounds or derivatives thereof having seven or more, or seven or more and 20 or less, or seven or more and 10 or less (meth)acryloyl groups.

Specifically, the polyfunctional (meth)acrylate compound may be a compound represented by the following Chemical Formula B. [Chemical Formula B] Wherein, in Formula B, _T7 to _T12 are the same as or different from each other and are each independently a (meth)acryl group, _T12 is hydrogen or a (meth)acryl group, and t is an integer from 2 to 10.

More specifically, in Formula B, _T7 to _T11 are acryloyl groups, _T12 is hydrogen or (meth)acryloyl groups, and t is an integer of 2 to 3.

Specific examples of the compound represented by Chemical Formula B include: (1) in Chemical Formula B, a compound having seven (meth)acryloyl groups, wherein _T7 to _T11 are acryloyl groups, _T12 is hydrogen, and t is an integer of 2, (2) in Chemical Formula B, a compound having eight (meth)acryloyl groups, wherein _T7 to _T11 are acryloyl groups, _T12 is acryloyl groups, and t is an integer of 2, (3) in Chemical Formula B, a compound having nine (meth)acryloyl groups, wherein _T7 to _T11 are acryloyl groups, _T12 is hydrogen, and t is an integer of 3, and (4) in Chemical Formula B, a compound having ten (meth)acryloyl groups, wherein _T7 to _T11 are acryloyl groups, _T12 is hydrogen, and t is an integer of 3.

The multifunctional (meth)acrylate compound having seven or more (meth)acryl groups may be one specific example corresponding to the compound represented by Chemical Formula B, or a mixture of two or more thereof.

Specifically, the multifunctional (meth)acrylate compound having 7 or more (meth)acryloyl groups may include a mixture of the following two types of compounds: a compound in which t is 2 in Chemical Formula B, and a compound in which t is 3 in Chemical Formula B. In this case, the content of the compound in which t is 3 in Chemical Formula B may be 1 part by weight or more and 40 parts by weight or less, or 5 parts by weight or more and 30 parts by weight or less, or 7 parts by weight or more and 28 parts by weight or less, based on 100 parts by weight of the compound in which t is 2 in Chemical Formula B.

The photopolymerizable compound may further include a hexa-type (meth)acrylate compound having six (meth)acryl groups. That is, in addition to at least one selected from the group consisting of a penta-type (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups, the photopolymerizable compound may further include a hexa-type (meth)acrylate compound having six (meth)acryl groups.

The six-type (meth)acrylate compound having six (meth)acryloyl groups may have six (meth)acryloyl groups. Each of the six (meth)acryloyl groups may be the same as or different from each other. The six-type (meth)acrylate compound may include all (meth)acrylate compounds having six (meth)acryloyl groups or derivatives thereof.

Specifically, the hexa-type (meth)acrylate compound may be a compound represented by the following Chemical Formula C. [Chemical Formula C] Wherein, in Chemical Formula C, _T12 to _T17 are the same as or different from each other and are each independently a (meth)acryloyl group. More specifically, in Chemical Formula 3, _T12 to _T17 are acryl groups.

Meanwhile, the photopolymerizable compound may further include a di(meth)acrylate compound having two (meth)acryl groups. The di(meth)acrylate compound having two (meth)acryl groups may include an alkylene glycol di(meth)acrylate or a bisphenol di(meth)acrylate.

As the alkylene glycol di(meth)acrylate, a compound represented by the following Chemical Formula D can be used. [Chemical Formula D] Wherein, in the chemical formula D, l+n is an integer of 2 or 3, and m is an integer of 12 to 18.

The compound represented by the chemical formula D can improve the hydrophobicity of the photosensitive resin composition, significantly increase the resistance to the developing solution and the coating solution, and shorten the peeling time of the cured film.

Relative to the total weight of the solid content of the photosensitive resin composition, the compound represented by Chemical Formula D may be 70 wt % or more and 90 wt % or less, or 75 wt % or more and 85 wt % or less.

If the content of the compound represented by chemical formula D is less than 70 wt % relative to the total weight of the solid content of the photosensitive resin composition, the effect produced by adding the compound represented by chemical formula D is insufficient, and if the content exceeds 90 wt %, there may be a problem of increased hydrophobicity and a rapid increase in the developing time in the post-exposure developing process.

As the bisphenol di(meth)acrylate, bisphenol di(meth)acrylate containing ethylene oxide can be used. The bisphenol di(meth)acrylate containing ethylene oxide can include two types of bisphenol di(meth)acrylate: bisphenol di(meth)acrylate containing 8 mol or less of ethylene oxide per molecule, and bisphenol di(meth)acrylate containing more than 8 mol and 16 mol or less of ethylene oxide per molecule.

Examples of bisphenol-based di(meth)acrylates containing 8 mol or less of ethylene oxide may include Miramer M244 (BPA(EO) ₃ DA, bisphenol A (EO) ₃ diacrylate), Miramer M240 (BPA(EO) ₄ DA, bisphenol A (EO) ₄ diacrylate), and Miramer M241 (bisphenol A (EO) ₄ dimethacrylate) manufactured by Miwon Specialty Chemical Co., Ltd.

Examples of bisphenol-based di(meth)acrylates containing greater than 8 mol and 16 mol or less than 16 mol of ethylene oxide may include Miramer M2100 (BPA(EO) ₁₀ DA, bisphenol A (EO) ₁₀ diacrylate), Miramer M2200 (BPA(EO) ₂₀ DA, bisphenol A (EO) ₂₀ diacrylate), and Miramer M2101 (bisphenol A (EO) ₁₀ dimethacrylate) manufactured by Miramer Specialty Chemicals, Inc.

More specifically, based on 100 parts by weight of the bisphenol-based di(meth)acrylate containing greater than 8 mol and 16 mol or less than 16 mol of ethylene oxide per molecule, the content of the bisphenol-based di(meth)acrylate containing 8 mol or less than 8 mol of ethylene oxide per molecule may be 100 parts by weight or less, 50 parts by weight or less, 1 part by weight or greater and 100 parts by weight or less, or 1 part by weight or greater and 50 parts by weight or less.

Based on the solid content, the content of the photopolymerizable compound may be 10% by weight or more and 70% by weight or less relative to the total weight of the photosensitive resin composition. When the content of the photopolymerizable compound is within the above range, effects such as enhanced photosensitivity, resolution, and adhesion may be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition excluding the solvent.

Based on the solid content, the photosensitive resin composition may include 20 wt % or more and 80 wt % or less of an alkaline developable binder resin, 1 wt % or more and 10 wt % or less of a photopolymerization initiator, and 10 wt % or more and 70 wt % or less of a photopolymerizable compound.

The photosensitive resin composition may further include a solvent. The solvent is generally selected from methyl ethyl ketone (MEK), methanol, THF, toluene and acetone, but is not particularly limited thereto, and its content may also be adjusted according to the content of the photopolymerization initiator, the alkaline developable binder resin and the photopolymerizable compound.

In addition, the photosensitive resin composition may further include other additives as needed. Other additives are plasticizers and may include: dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diallyl phthalate in the form of phthalate esters; triethylene glycol diacetate, tetraethylene glycol diacetate in the form of ethylene glycol esters; p-toluenesulfonamide, benzenesulfonamide, n-butylbenzenesulfonamide in the form of acid amides; triphenyl phosphate, etc.

In order to improve the handling property of the photosensitive resin composition, a colorless dye or a coloring material may also be added. Examples of colorless dyes include tris(4-dimethylamino-2-methylphenyl)methane, tris(4-dimethylamino-2-methylphenyl)methane, fluorane dyes, etc. Among them, when colorless crystal violet is used, the contrast is good, so this is preferred. When a colorless dye is contained, its content in the photosensitive resin composition may be 0.01% by weight or more and 1% by weight or less. From the perspective of showing contrast, 0.01% by weight or more is preferred, and from the perspective of maintaining storage stability, 1% by weight or less is preferred.

Examples of the coloring material may include toluenesulfonic acid monohydrate, fuchsin, phthalocyanine green, auramine, para-fuchsin, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, diamond green, basic blue 20, etc. When the coloring material is contained, its addition amount in the photosensitive resin composition may be 0.001 wt % or more and 1 wt % or less. When the content is 0.001 wt % or more, it has the effect of improving the handling property, and when the content is 1 wt % or less, it has the effect of maintaining the storage stability.

In addition, other additives may further include thermal polymerization inhibitors, dyes, decolorizing agents, and adhesion promoters.

Meanwhile, the photosensitive resin layer may contain a photosensitive resin composition comprising an alkaline developable binder resin, a photopolymerization initiator and a photopolymerizable compound, wherein the alkaline developable binder resin comprises four or more polymers that are different from each other.

The inventors have experimentally confirmed that a photosensitive resin composition containing four or more different polymers as photopolymerizable compounds has excellent peeling properties, reduces contamination of the coating solution, and allows coating to be performed with sufficient thickness, thereby completing the present disclosure.

The alkaline developable binder resin may include four or more polymers that are different from each other. The four or more types of polymers may have different configurations depending on the type of repeating units constituting each polymer.

Specifically, the alkali-developable binder resin may include a first binder resin containing a repeating unit represented by the following Chemical Formula 1. That is, the alkali-developable binder resin may include a first binder resin containing a repeating unit represented by the following Chemical Formula 1; and three or more types of polymers different therefrom. [Chemical Formula 1] Wherein, in Chemical Formula 1, _R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, _R2 is an alkylene group having 1 to 10 carbon atoms, Ar is an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 20.

Since the first binder resin contains the repeating unit represented by Chemical Formula 1 and thereby the hydrophobicity of the first binder resin is increased through the benzene structure contained in the repeating unit represented by Chemical Formula 1, it suppresses the generation of bubbles in the development process of the dry film photoresist using the photosensitive resin composition and thus exhibits excellent development properties, and can improve substrate adhesion and thus ensure appropriate physical properties (resolution, fine line adhesion, etc.).

In Chemical Formula 1, R ₁ may be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms may include a methyl group.

In Chemical Formula 1, R ₂ is an alkylene group having 1 to 10 carbon atoms, and specific examples of the alkylene group having 1 to 10 carbon atoms may include an ethylene group.

In Chemical Formula 1, Ar is an aryl group having 6 to 20 carbon atoms, and a specific example of the aryl group having 6 to 20 carbon atoms may be a phenyl group.

The repeating unit represented by Chemical Formula 1 may be a repeating unit derived from a monomer represented by the following Chemical Formula 1-1. [Chemical Formula 1-1] Wherein, in Chemical Formula 1-1, _R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, _R2 is an alkylene group having 1 to 10 carbon atoms, Ar is an aryl group having 6 to 20 carbon atoms, and n is an integer from 1 to 20. In Chemical Formula 1-1, the definitions of _R1 , _R2 , Ar and n are the same as those described above for Chemical Formula 1.

Specific examples of the monomer represented by Chemical Formula 1-1 may include phenoxypolyethyleneoxyacrylate, more specifically 2-phenoxyethyl methacrylate (PHEMA).

The content of the repeating unit represented by Chemical Formula 1 may be 5 mol% or more and 40 mol% or less, or 5 mol% or more and 30 mol% or less, or 5 mol% or more and 25 mol% or less, or 10 mol% or more and 25 mol% or less, based on 100 mol% of the total molar content of the repeating units contained in the alkaline developable binder resin.

In addition to the repeating unit represented by Chemical Formula 1, the first binder resin may further include a repeating unit represented by the following Chemical Formula 2, a repeating unit represented by the following Chemical Formula 3, and a repeating unit represented by the following Chemical Formula 4: [Chemical Formula 2] Wherein, in Chemical Formula 2, R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 3] Wherein, in Chemical Formula 3, _R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and _R5 is an alkyl group having 1 to 10 carbon atoms, and [Chemical Formula 4] In Chemical Formula 4, Ar is an aromatic group having 6 to 20 carbon atoms.

Specifically, the alkali developable binder resin may include a random copolymer of a repeating unit represented by Chemical Formula 1, a repeating unit represented by Chemical Formula 2, a repeating unit represented by Chemical Formula 3, and a repeating unit represented by Chemical Formula 4.

In Chemical Formulae 2 to 4, _R3 and _R4 are the same as or different from each other and are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms, _R5 is an alkyl group having 1 to 10 carbon atoms, and Ar is an aryl group having 6 to 20 carbon atoms.

In Chemical Formulae 2 to 4, R ₃ and R ₄ are the same as or different from each other and may each independently be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group.

R ₅ is an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group.

Ar is an aryl group having 6 to 20 carbon atoms, and specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group.

The repeating unit represented by Chemical Formula 2 may be a repeating unit derived from a monomer represented by the following Chemical Formula 2-1. [Chemical Formula 2-1] Wherein, in Chemical Formula 2-1, R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms. In Chemical Formula 2-1, the definition of R ₃ is the same as that described above for Chemical Formula 2. Specific examples of the monomer represented by Chemical Formula 2-1 may include methacrylic acid (MAA).

The repeating unit represented by Chemical Formula 3 may be a repeating unit derived from a monomer represented by the following Chemical Formula 3-1. [Chemical Formula 3-1] Wherein, in Chemical Formula 3-1, _R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and _R5 is an alkyl group having 1 to 10 carbon atoms. In Chemical Formula 3-1, _R4 and _R5 are defined the same as those described above for Chemical Formula 3. Specific examples of the monomer represented by Chemical Formula 3-1 may include methyl methacrylate (MMA).

The repeating unit represented by Chemical Formula 4 may include a repeating unit derived from a monomer represented by the following Chemical Formula 4-1. [Chemical Formula 4-1] Wherein, in Chemical Formula 4-1, Ar is an aryl group having 6 to 20 carbon atoms. In Chemical Formula 4-1, the definition of Ar is the same as that described above for Chemical Formula 4. Specific examples of the monomer represented by Chemical Formula 4-1 may include styrene (SM).

The first binder resin may contain 20 mol% or more and 60 mol% or less, or 20 mol% or more and 50 mol% or less, or 30 mol% or more and 40 mol% or less of the repeating unit represented by Chemical Formula 2, based on 100 mol% of the total molar content of the repeating units contained in the first binder resin.

In addition, the first binder resin may contain 1 mol% or more and 30 mol% or less, or 5 mol% or more and 30 mol% or less, of the repeating unit represented by Chemical Formula 3, and 30 mol% or more and 60 mol% or less, or 30 mol% or more and 50 mol% or less, or 30 mol% or more and 40 mol% or less of the repeating unit represented by Chemical Formula 4, based on 100 mol% of the total molar content of the repeating units contained in the first binder resin.

More specifically, the molar ratio of the repeating unit represented by Chemical Formula 3, relative to 100 moles of the repeating unit represented by Chemical Formula 4, may be 10 moles or more and 99 moles or less, or 15 moles or more and 95 moles or less, or 20 moles or more and 95 moles or less.

In addition, the molar ratio of the repeating unit represented by Chemical Formula 3 with respect to 100 moles of the repeating unit represented by Chemical Formula 1 may be 40 moles or less, or 35 moles or less, or 32 moles or less, or 0.1 mole or more and 40 moles or less, or 0.1 mole or more and 35 moles or less, or 0.1 mole or more and 32 moles or less, or 10 moles or more and 40 moles or less, or 10 moles or more and 35 moles or less, or 10 moles or more and 32 moles or less.

Thus, as the content of the hydrophobic repeating unit represented by Chemical Formula 4 increases, the hydrophobicity of the first binder resin also increases, thereby being able to suppress the generation of bubbles during the development process of the dry film photoresist using the photosensitive resin composition.

The first binder resin may have a weight average molecular weight of 30,000 g/mol or more and 150,000 g/mol or less, and a glass transition temperature of 20° C. or more and 150° C. or less. This can improve the coating property and followability of the dry film photoresist, as well as the mechanical strength of the resist itself after circuit formation.

The weight average molecular weight used herein refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). In the process of measuring the weight average molecular weight in terms of polystyrene measured by GPC, a detector and an analysis column such as a well-known analysis device and a differential refractive index detector can be used, and generally used temperature conditions, solvents, and flow rates can be used.

A specific example of the measurement conditions is as follows: an alkali developable binder resin is dissolved in tetrahydrofuran so that its concentration in THF is 1.0 (w/w) % (about 0.5 (w/w) % in terms of solid content), filtered using a syringe filter having a pore size of 0.45 μm, and then injected into a GPC in an amount of 20 μl, using tetrahydrofuran (THF) as a mobile phase of the GPC, and a flow rate of 1.0 ml/min. The column consisted of an Agilent Plagal 5 μm guard column (7.5 mm×50 mm) and two Agilent Plagal 5 μm mixed D columns (7.5 mm×300 mm) connected in series, and the measurement was performed at 40° C. by an RI detector using an Agilent 1260 Infinity II system as a detector.

Polystyrene standard samples (STD A, B, C, D) in which polystyrene having various molecular weights as described below was dissolved in tetrahydrofuran at a concentration of 0.1 (w/w)% were filtered through a syringe filter having a pore size of 0.45 μm and then injected into the GPC, and the weight average molecular weight (Mw) value of the alkaline developable binder resin was determined using a calibration curve. STD A (Mp): 791,000 / 27,810 / 945 STD B (Mp): 282,000 / 10,700 / 580 STD C (Mp): 126,000 / 4,430 / 370 STD D (Mp): 51,200 / 1,920 / 162

The glass transition temperatures of the reference polymer and the binder polymer were compared by differential scanning calorimetry (DSC) (Perkin-Elmer, DSC-7). The measurement was performed by keeping the temperature at 20°C for 15 minutes and then increasing the temperature to 200°C at a rate of 1°C/min.

The acid value of the first binder resin may be 120 mgKOH/g or more and 200 mgKOH/g or less, or 140 mgKOH/g or more and 160 mgKOH/g or less. The acid value is measured by the following process: in the process, about 1 g of the alkaline developable binder resin is sampled, dissolved in 50 ml of a mixed solvent (MeOH 20%, acetone 80%) to which two drops of 1% phenolphthalein indicator are added, and then titrated with 0.1N-KOH to measure the acid value.

Meanwhile, the alkali-developable binder resin may include a second binder resin containing a repeating unit represented by the following Chemical Formula 5. That is, the alkali-developable binder resin may include a second binder resin containing a repeating unit represented by the following Chemical Formula 5; and three or more types of polymers different therefrom. [Chemical Formula 5] Wherein, in Chemical Formula 5, _R6 is hydrogen, and _R7 is an alkyl group having 1 to 10 carbon atoms. Specific examples of the alkyl group having 1 to 10 carbon atoms include a butyl group.

In addition to the repeating unit represented by Chemical Formula 5, the second binder resin may further include a repeating unit represented by the following Chemical Formula 6, a repeating unit represented by the following Chemical Formula 7, a repeating unit represented by the following Chemical Formula 8, and a repeating unit represented by the following Chemical Formula 9. [Chemical Formula 6] Wherein, in Chemical Formula 6, R ₈ is hydrogen, [Chemical Formula 7] Wherein, in Chemical Formula 7, R ₉ is an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 8] Wherein, in Chemical Formula 8, R ₁₀ is an alkyl group having 1 to 10 carbon atoms, and R ₁₁ is an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 9] In Chemical Formula 9, Ar is an aromatic group having 6 to 20 carbon atoms.

In Chemical Formulae 6 to 9, specific examples of the alkyl group having 1 to 10 carbon atoms may include a methyl group.

Ar is an aryl group having 6 to 20 carbon atoms, and specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group.

The second binder resin may have a weight average molecular weight of 30,000 g/mol or more and 150,000 g/mol or less, and a glass transition temperature of 20° C. or more and 150° C. or less. This can improve the coating property and followability of the dry film photoresist and the mechanical strength of the resist itself after the circuit is formed. In addition, the second binder resin may have an acid value of 140 mgKOH/g or more and 160 mgKOH/g or less.

Specifically, the second binder resin may include a random copolymer of a repeating unit represented by Chemical Formula 5, a repeating unit represented by Chemical Formula 6, a repeating unit represented by Chemical Formula 7, a repeating unit represented by Chemical Formula 8, and a repeating unit represented by Chemical Formula 9.

More specifically, the second binder resin may contain 5 mol% or more and 20 mol% or less of the repeating unit represented by Chemical Formula 5, 5 mol% or more and 20 mol% or less of the repeating unit represented by Chemical Formula 6, 5 mol% or more and 20 mol% or less of the repeating unit represented by Chemical Formula 7, 40 mol% or more and 80 mol% or less of the repeating unit represented by Chemical Formula 8, and 5 mol% or more and 15 mol% or less of the repeating unit represented by Chemical Formula 9, based on 100 mol% of all repeating units.

Meanwhile, the alkali-developable binder resin may include a third binder resin containing a repeating unit represented by the following Chemical Formula 10, a repeating unit represented by the following Chemical Formula 11, and a repeating unit represented by the following Chemical Formula 12. That is, the alkali-developable binder resin may include the third binder resin; and three or more types of polymers different therefrom, [Chemical Formula 10] Wherein, in Chemical Formula 10, R ₉ is an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 11] Wherein, in Chemical Formula 11, R ₁₀ is an alkyl group having 1 to 10 carbon atoms, and R ₁₁ is an alkyl group having 1 to 10 carbon atoms, and [Chemical Formula 12] In Chemical Formula 12, Ar is an aromatic group having 6 to 20 carbon atoms.

More specifically, based on 100 mol% of all repeating units, the third binder resin may contain 20 mol% or more and 40 mol% or less of the repeating unit represented by Chemical Formula 10, 50 mol% or more and 70 mol% or less of the repeating unit represented by Chemical Formula 11, and 5 mol% or more and 18 mol% or less of the repeating unit represented by Chemical Formula 12.

In addition, the third binder resin may have a weight average molecular weight of 20,000 g/mol or more and 130,000 g/mol or less, and a glass transition temperature of 30° C. or more and 160° C. or less. This can improve the coating property and followability of the dry film photoresist, as well as the mechanical strength of the resistor itself after the circuit is formed.

The second binder resin may have an acid value of 140 mgKOH/g or more and 160 mgKOH/g or less. In addition, the third binder resin may have an acid value of 160 mgKOH/g or more and 200 mgKOH/g or less.

Meanwhile, the alkali-developable binder resin may include a fourth binder resin containing a repeating unit represented by the following Chemical Formula 13. That is, the alkali-developable binder resin may include a fourth binder resin; and three or more types of polymers different therefrom, [Chemical Formula 13] Wherein, in Chemical Formula 13, R ₁₂ is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R ₁₃ is an alkylene group having 1 to 10 carbon atoms.

In Chemical Formula 13, R ₁₂ may be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group.

In Chemical Formula 13, R ₁₃ is an alkylene group having 1 to 10 carbon atoms, and specific examples of the alkylene group having 1 to 10 carbon atoms include a methylene group.

Since the fourth binder resin contains the repeating unit represented by Chemical Formula 13, it can achieve the effect of suppressing the elution of the resist in the plating solution due to excellent developing characteristics and thermal curing by drying heat.

In addition to the repeating unit represented by Chemical Formula 13, the fourth binder resin may further include a repeating unit represented by the following Chemical Formula 14, a repeating unit represented by the following Chemical Formula 15, and a repeating unit represented by the following Chemical Formula 16. [Chemical Formula 14] Wherein, in Chemical Formula 14, R ₁₄ is hydrogen or an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 15] Wherein, in Chemical Formula 15, R ₁₅ is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R ₁₆ is an alkyl group having 1 to 10 carbon atoms, [Chemical Formula 16] In Chemical Formula 16, Ar is an aromatic group having 6 to 20 carbon atoms.

Specifically, the alkali developable binder resin may include a random copolymer of a repeating unit represented by Chemical Formula 13, a repeating unit represented by Chemical Formula 14, a repeating unit represented by Chemical Formula 15, and a repeating unit represented by Chemical Formula 16.

In Chemical Formulae 14 to 16, R ₁₄ and R ₁₅ are the same as or different from each other and are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms, R ₁₆ is an alkyl group having 1 to 10 carbon atoms, and Ar is an aryl group having 6 to 20 carbon atoms.

In Chemical Formulae 14 to 16, R ₁₄ and R ₁₅ are the same as or different from each other and may each independently be any one of hydrogen or an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group.

R ₁₆ is an alkyl group having 1 to 10 carbon atoms, and specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group.

Ar is an aryl group having 6 to 20 carbon atoms, and specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group.

The fourth binder resin may have a weight average molecular weight of 20,000 g/mol or more and 130,000 g/mol or less, and a glass transition temperature of 30° C. or more and 160° C. or less. This can improve the coating property and followability of the dry film photoresist and the mechanical strength of the resistor itself after the circuit is formed. In addition, the fourth binder resin may have an acid value of 140 mgKOH/g or more and 180 mgKOH/g or less.

More specifically, based on 100 mol% of all repeating units, the fourth binder resin may contain 15 mol% or more and 25 mol% or less of the repeating unit represented by Chemical Formula 13, 30 mol% or more and 50 mol% or less of the repeating unit represented by Chemical Formula 14, 15 mol% or more and 25 mol% or less of the repeating unit represented by Chemical Formula 15, and 20 mol% or more and 30 mol% or less of the repeating unit represented by Chemical Formula 16.

Specifically, the alkaline developable binder resin may include a first binder resin; a second binder resin; a third binder resin; and a fourth binder resin. More specifically, based on 100 wt % of the alkaline developable binder resin, the photosensitive resin composition of one embodiment of the present disclosure may contain 40 wt % or more and 80 wt % or less of the first binder resin, 0.1 wt % or more and 4 wt % or less of the second binder resin, 10 wt % or more and 20 wt % or less of the third binder resin, and 5 wt % or more and 45 wt % or less of the fourth binder resin.

Specifically, based on 100 parts by weight of the first binder resin, the content of the fourth binder resin may be 10 parts by weight or more and 90 parts by weight or less.

In addition, based on 100 parts by weight of the second binder resin, the content of the fourth binder resin may be 500 parts by weight or more and 3000 parts by weight or less, or 600 parts by weight or more and 2700 parts by weight or less.

Since the fourth binder resin is contained in a specific amount in this manner, the effect of suppressing the elution of the resist in the plating solution can be achieved due to excellent developing characteristics and thermal curing by dry heat.

In addition, based on 100 parts by weight of the second binder resin, the content of the third binder resin may be 500 parts by weight or more and 1000 parts by weight or less, 600 parts by weight or more and 800 parts by weight or less, and 700 parts by weight or more and 800 parts by weight or less.

As described above, by adding the third binder resin in an amount exceeding 500 parts by weight or greater than 500 parts by weight based on 100 parts by weight of the second binder resin, the technical effects of imparting hydrophobic function to the photosensitive resin, increasing tolerance to developing solutions, and improving physical properties of the circuit can be achieved.

Based on the solid content, the content of the alkaline developable binder resin is 20 wt % or more and 80 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the alkaline developable binder resin is within the above range, the effect of enhancing the adhesion of fine lines after circuit formation can be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition except the solvent.

The content of the alkaline developable binder resin may be 40 wt % or more and 70 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the alkaline developable binder resin is less than 40 wt % based on the total photosensitive resin composition, there is a disadvantage of causing defects such as short circuits due to contamination in development, and when the content of the alkaline developable binder resin exceeds 70 wt %, there is a problem of deterioration of circuit properties such as adhesion and resolution.

The photopolymerization initiator contained in the photosensitive resin composition is a material that initiates the chain reaction of photopolymerizable monomers by UV and other radiation, and plays an important role in curing dry film photoresist.

Compounds that may be used as photopolymerization initiators may include anthraquinone derivatives such as 2-methylanthraquinone and 2-ethylanthraquinone, and benzoin derivatives such as benzoin methyl ether, benzophenone, phenanthrenequinone, and 4,4′-bis-(dimethylamino)benzophenone.

In addition, selected from 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-[4-morpholinophenyl]butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzyldiphenylphosphine oxide, 1-[4-(2- [(4-hydroxymethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, 2,4-diethylthiothione, 2-chlorothiothione, 2,4-dimethylthiothione, 3,3-dimethyl-4-methoxybenzophenone, benzophenone, 1-chloro-4-propoxythiothione, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-benzoyl-4'-methyl dimethyl sulfide, 4-dimethylaminobenzoic acid, 4- Methyl dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-isoamyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyl ketone dimethyl acetal, benzyl ketone β-methoxydiethyl acetal, 1-phenyl-1,2-propanedioxime-o,o'-(2-carbonyl)ethoxy ether, methyl o-benzoylbenzoate, bis[4-dimethylaminophenyl]ketone, 4,4'-bis(diethylamino)benzophenone The photopolymerization initiator may be a compound selected from the group consisting of 4,4'-dichlorobenzophenone, benzyl, benzoin, methoxybenzoin, ethoxybenzoin, isopropoxybenzoin, n-butoxybenzoin, isobutoxybenzoin, tert-butoxybenzoin, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thiothionone, 2-methylthiothionone, 2-isopropylthiothionone, dibenzocycloheptanone, α,α-dichloro-4-phenoxyacetophenone and 4-dimethylaminobenzoic acid amyl ester, but is not limited thereto.

Based on the solid content, the content of the photopolymerization initiator is 1 wt % or more and 10 wt % or less relative to the total weight of the photosensitive resin composition. When the content of the photopolymerization initiator is within the above range, sufficient sensitivity can be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition except the solvent.

When the content of the photopolymerization initiator is less than 1 wt %, the light efficiency is low and a large amount of exposure must be applied, and therefore, there is a disadvantage that the production efficiency is greatly reduced. When the content of the photopolymerization initiator exceeds 10 wt %, there are problems that the film is fragile and the contamination of the developing solution increases, resulting in defects such as short circuits.

Photopolymerizable compounds are resistant to developer solutions after UV exposure and can form patterns.

The photopolymerizable compound may include a difunctional (meth)acrylate compound. The difunctional (meth)acrylate compound may include an alkylene glycol-based di(meth)acrylate or a bisphenol-based di(meth)acrylate.

As the alkylene glycol di(meth)acrylate, a compound represented by the following Chemical Formula 17 can be used. [Chemical Formula 17] In chemical formula 17, l+n is an integer of 2 or 3, and m is an integer of 12 to 18.

The compound represented by Chemical Formula 17 can improve the hydrophobicity of the photosensitive resin composition, significantly increase the resistance to the developing solution and the coating solution, and shorten the peeling time of the cured film.

Relative to the total weight of the solid content of the photosensitive resin composition, the compound represented by Chemical Formula 17 may be 10 wt % or more and 60 wt % or less, or 20 wt % or more and 40 wt % or less.

If the content of the compound represented by Chemical Formula 17 is less than 10 wt % relative to the total weight of the solid content of the photosensitive resin composition, the effect produced by adding the compound represented by Chemical Formula 17 is insufficient, and if the content exceeds 60 wt %, there may be a problem of increased hydrophobicity and a rapid increase in the developing time in the post-exposure developing process.

As the bisphenol di(meth)acrylate, bisphenol di(meth)acrylate containing ethylene oxide can be used. The bisphenol di(meth)acrylate containing ethylene oxide can include two types of bisphenol di(meth)acrylate: bisphenol di(meth)acrylate containing 8 mol or less of ethylene oxide per molecule, and bisphenol di(meth)acrylate containing more than 8 mol and 16 mol or less of ethylene oxide per molecule.

Examples of bisphenol-based di(meth)acrylates containing 8 mol or less of ethylene oxide may include Miramer M244 (BPA(EO) ₃ DA, bisphenol A (EO) ₃ diacrylate), Miramer M240 (BPA(EO) ₄ DA, bisphenol A (EO) ₄ diacrylate), and Miramer M241 (bisphenol A (EO) ₄ dimethacrylate) manufactured by Miramer Specialty Chemicals, Inc.

Examples of bisphenol-based di(meth)acrylates containing greater than 8 mol and 16 mol or less than 16 mol of ethylene oxide may include Miramer M2100 (BPA(EO) ₁₀ DA, bisphenol A (EO) ₁₀ diacrylate), Miramer M2200 (BPA(EO) ₂₀ DA, bisphenol A (EO) ₂₀ diacrylate), and Miramer M2101 (bisphenol A (EO) ₁₀ dimethacrylate) manufactured by Miramer Specialty Chemicals, Inc.

More specifically, based on 100 parts by weight of the bisphenol-based di(meth)acrylate containing greater than 8 mol and 16 mol or less than 16 mol of ethylene oxide per molecule, the content of the bisphenol-based di(meth)acrylate containing 8 mol or less than 8 mol of ethylene oxide per molecule may be 100 parts by weight or less, 50 parts by weight or less, 1 part by weight or greater and 100 parts by weight or less, or 1 part by weight or greater and 50 parts by weight or less.

Based on the solid content, the content of the photopolymerizable compound may be 10% by weight or more and 70% by weight or less relative to the total weight of the photosensitive resin composition. When the content of the photopolymerizable compound is within the above range, effects such as enhanced photosensitivity, resolution, and adhesion may be obtained. The solid content as a weight basis refers to the remaining components in the photosensitive resin composition excluding the solvent.

Based on the solid content, the photosensitive resin composition may include 20 wt % or more and 80 wt % or less of an alkaline developable binder resin, 1 wt % or more and 10 wt % or less of a photopolymerization initiator, and 10 wt % or more and 70 wt % or less of a photopolymerizable compound.

The photosensitive resin composition may further include a solvent. The solvent is generally selected from methyl ethyl ketone (MEK), methanol, THF, toluene and acetone, but is not particularly limited thereto, and its content may also be adjusted according to the content of the photopolymerization initiator, the alkaline developable binder resin and the photopolymerizable compound.

In addition, the photosensitive resin composition may further include other additives as needed. Other additives are plasticizers and may include: dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diallyl phthalate in the form of phthalate esters; triethylene glycol diacetate, tetraethylene glycol diacetate in the form of ethylene glycol esters; p-toluenesulfonamide, benzenesulfonamide, n-butylbenzenesulfonamide in the form of amides; triphenyl phosphate, etc.

In order to improve the handling properties of the photosensitive resin composition, a colorless dye or a coloring material may also be added. Examples of colorless dyes include tris(4-dimethylamino-2-methylphenyl)methane, tris(4-dimethylamino-2-methylphenyl)methane, fluorane dyes, etc. Among them, when colorless crystal violet is used, the contrast is good, so this is preferred. When a colorless dye is contained, its content in the photosensitive resin composition may be 0.01% by weight or more and 1% by weight or less. From the perspective of showing contrast, 0.01% by weight or more is preferred, and from the perspective of maintaining storage stability, 1% by weight or less is preferred.

Examples of the coloring material may include toluenesulfonic acid monohydrate, fuchsin, phthalocyanine green, auramine, para-fuchsin, crystal violet, methyl orange, Nile Blue 2B, Victoria Blue, malachite green, diamond green, basic blue 20, etc. When the coloring material is contained, its addition amount in the photosensitive resin composition may be 0.001 wt % or more and 1 wt % or less. When the content is 0.001 wt % or more, it has the effect of improving the handling property, and when the content is 1 wt % or less, it has the effect of maintaining storage stability.

In addition, other additives may include thermal polymerization inhibitors, dyes, decolorizers, and adhesion promoters.

According to another embodiment of the present disclosure, a dry film photoresist may be provided, the dry film photoresist comprising: a photosensitive resin composition comprising an alkaline developable binder resin, a photopolymerization initiator, and a photopolymerizable compound, wherein the photopolymerizable compound comprises a penta-type (meth)acrylate compound having five (meth)acrylic groups and a multifunctional (meth)acrylic compound having seven or more (meth)acrylic groups. At least one of the group consisting of (meth)acrylate compounds, and the dry film photoresist has a feature of a palladium coating layer having a thickness of 0.01 micrometer or greater, wherein the palladium coating layer is obtained by immersing a film sample in which a photosensitive resin layer of the dry film photoresist is stacked on a substrate in a palladium coating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium coating solution for 5 minutes.

According to another embodiment of the present disclosure, a dry film photoresist may be provided, the dry film photoresist comprising: a photosensitive resin composition comprising an alkaline developable binder resin, a photopolymerization initiator and a photopolymerizable compound, wherein the alkaline developable binder resin comprises four or more polymers that are different from each other, and wherein the dry film photoresist has a characteristic of a palladium-plated layer having a thickness of 0.01 μm or more, the palladium-plated layer being obtained by immersing a film sample in which the photosensitive resin layers of the dry film photoresist are stacked on a substrate in a palladium-plating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium-plating solution for 5 minutes.

Details regarding the photosensitive resin composition comprising an alkaline developable binder resin, a photopolymerization initiator, and a photopolymerizable compound include all of the above described with respect to one embodiment, wherein the photopolymerizable compound comprises at least one selected from the group consisting of a pentatype (meth)acrylate compound having five (meth)acryl groups and a multifunctional (meth)acrylate compound having seven or more (meth)acryl groups.

Details regarding the photosensitive resin composition comprising an alkaline developable binder resin, a photopolymerization initiator, and a photopolymerizable compound include all of the contents described above with respect to one embodiment, wherein the alkaline developable binder resin comprises four or more polymers that are different from each other.

Specifically, the photosensitive resin layer may include a dried product or a cured product of the photosensitive resin composition. The dried product refers to a material obtained by a drying step of the photosensitive resin composition. The cured product refers to a material obtained by a curing step of the photosensitive resin composition. The thickness of the photosensitive resin layer is not particularly limited, but, for example, it can be freely adjusted within a range of 0.01 micrometers to 1 millimeter.

The thickness of the dry film photoresist is not particularly limited, but for example, it can be freely adjusted within the range of 0.01 micrometers to 1 millimeter. When the thickness of the dry film photoresist increases or decreases by a specific value, the physical properties measured in the dry film photoresist may also change by a specific value.

The dry film photoresist may further include a substrate film and a protective film. The substrate film is used as a support for the photosensitive resin layer during the manufacturing of the dry film photoresist and is conducive to handling the photosensitive resin layer during exposure with adhesive strength.

Various plastic films may be used as the substrate film, and examples thereof may include at least one plastic film selected from the group consisting of an acrylic film, a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, a polynorbornene (PNB) film, a cycloolefin polymer (COP) film, and a polycarbonate (PC) film. The thickness of the substrate film is not particularly limited, and, for example, it may be freely adjusted within a range of 0.01 μm to 1 mm.

The protective film prevents the resist from being damaged during handling, and functions as a protective covering to protect the photoresist layer from foreign matter (such as dust), and the protective film layer is superimposed on the back side of the photoresist layer on which the substrate film is not formed. The protective film is used to protect the photoresist layer from external influences. When the dry film photoresist is applied for post-processing, it needs to be easily detached, and it needs appropriate releasability and adhesion to allow it to be deformed during storage and distribution.

Various plastic films may be used as the protective film, and examples thereof may include at least one plastic film selected from the group consisting of acrylic film, polyethylene (PE) film, polyethylene terephthalate (PET) film, triacetyl cellulose (TAC) film, polynorbornene (PNB) film, cycloolefin polymer (COP) film, and polycarbonate (PC) film. The thickness of the protective film is not particularly limited, and, for example, it can be freely adjusted within the range of 0.01 μm to 1 mm.

An example of a method for manufacturing a dry film photoresist is not particularly limited, and for example, a photosensitive resin composition of an embodiment is coated on a conventional substrate film such as polyethylene terephthalate using a conventional coating method, and then dried, and the upper surface of the dried photosensitive resin layer is stacked with a conventional protective film layer such as polyethylene to manufacture a dry film.

The method of applying the photosensitive resin composition of one embodiment is not particularly limited, and a method such as a coating bar may be used.

The step of drying the coated photosensitive resin composition may be performed by a heating device such as a hot air oven, a hot plate, a hot air circulation furnace, and an infrared furnace, and may be performed at a temperature of 50° C. or more and 120° C. or less.

Meanwhile, the dry film photoresist has a feature that the thickness of the palladium plating layer may be 0.01 μm or more, or 0.05 μm or more, or 0.1 μm or more, or 0.01 μm or more and 0.15 μm or less, or 0.05 μm or more and 0.15 μm or less, or 0.1 μm or more and 0.15 μm or less, and the palladium plating layer is obtained by immersing a film sample in which a photosensitive resin layer of the dry film photoresist is stacked on a substrate in a palladium plating solution for 60 minutes and then immersing a copper-clad laminate sample in the residual palladium plating solution for 5 minutes.

The residual palladium plating solution is a palladium plating solution contaminated by the components of the photosensitive resin layer, and the thickness of the palladium plating layer obtained by immersing the copper-clad laminate sample in the contaminated residual palladium plating solution for 5 minutes is used to evaluate the contamination of the plating solution by the dry film photoresist when palladium is plated on the laminate with the photosensitive resin layer stacked thereon. As the contamination of the plating solution becomes more serious, the thickness of the palladium plating layer obtained by immersing the copper-clad laminate sample in the palladium plating solution for 5 minutes becomes significantly lower. On the other hand, as the plating solution is less contaminated, the thickness of the palladium-plated layer obtained by immersing the copper-clad laminate sample in the contaminated palladium plating solution for 5 minutes becomes significantly higher. Therefore, during the actual electroless palladium plating process, the contaminants accumulate in the bulk dry film resist, and only palladium is added for continuous plating, which makes other cleaning treatments difficult. Therefore, it is extremely important to evaluate the extent to which the palladium plating solution is contaminated by the dry film resist.

That is, in palladium plating, first, a first palladium plating using a film on which a photosensitive resin layer is laminated is performed. After the first plating has been completed, a second palladium plating is performed on a new copper-clad laminate sample in a contaminated palladium plating solution, and the nature of the plating solution being contaminated by the dry film photoresist is evaluated with respect to the thickness of the palladium plating layer at the second plating.

Therefore, the thickness of the palladium coating layer obtained by immersing the film sample in which the photosensitive resin layer is stacked on the substrate in the palladium coating solution for 60 minutes and then immersing the copper-clad laminate sample in the residual palladium coating solution for 5 minutes is excessively reduced to less than 0.01 micrometers, which makes it possible to evaluate the contamination level of the coating solution. When evaluating the contamination level, when the coating layer is coated to a thickness lower than the target value, the contamination of the electroless palladium coating solution is serious in the actual process, and therefore, it is difficult to reuse the coating solution exceeding 0.5 MTO, which may be disadvantageous in terms of process efficiency and economy.

The method of calculating the thickness of the palladium coating layer is not particularly limited, and various known methods for measuring the thickness of the coating layer can be applied without limitation. For example, the measurement can be performed by an XRF coating thickness measuring instrument (Helmut Fischer XDV-μ).

A more specific example of a method of obtaining a residual palladium plating solution after immersing a film sample in which a photosensitive resin is layered on a substrate in the palladium plating solution for 60 minutes is described below.

First, the copper-clad laminate sample with the photosensitive resin layer stacked thereon may be immersed in a nickel-phosphorus solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the photosensitive resin layer stacked thereon in the nickel-phosphorus solution are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 660 square centimeters or less may be immersed in a nickel-phosphorus solution at 65°C or more and 95°C or less. A sample of 0 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of NPR-4 (Uemura) plating solution (as a nickel-phosphorus-containing plating solution) for 20 minutes or more and 60 minutes or less to perform elution. The cross-sectional area refers to the area of a cross section obtained by cutting the sample in a direction perpendicular to the direction in which the thickness of the sample increases.

If necessary, the sample may be immersed in a catalyst aqueous solution before being immersed in a nickel-phosphorus plating solution, and the specific conditions are not particularly limited. For example, a copper-clad laminate sample in which photosensitive water is layered on a substrate may be immersed for 30 seconds to 90 seconds under the conditions of 10° C. or more and 40° C. or less by using CATA NC-20 (MK Chemical & Technology Co., Ltd.) as a palladium-plating catalyst solution.

Next, the copper-clad laminate sample with the nickel-plated photosensitive resin layer stacked thereon may be immersed in a palladium plating solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the nickel-plated photosensitive resin layer stacked thereon are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 700 square centimeters or less, may be immersed in a palladium plating solution at 30°C or more and 70°C or less. A sample of 660 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of TPD-21 (Uemura) coating solution (as a palladium coating solution) for 30 minutes or more and 90 minutes or less to perform elution.

At the same time, the copper-clad laminate sample with the palladium-plated photosensitive resin layer stacked thereon may be immersed in the gold plating solution to perform elution. Although the specific conditions for immersing the copper-clad laminate sample with the palladium-plated photosensitive resin layer thereon are not particularly limited, for example, a copper-clad laminate sample with a cross-sectional area of 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 640 square centimeters or less may be immersed in the gold plating solution at 65°C or more and 95°C or less. A sample of 60 cm2 or less, or 645 cm2 or more and 655 cm2 or less, or 650 cm2 is immersed in 130 ml of TMX-40 (Uemura) plating solution (as a gold plating solution) for 50 minutes or more and 150 minutes or less to perform elution.

Meanwhile, a more specific example of a method for measuring the thickness of a palladium-plated layer obtained by immersing a copper-clad laminate sample in a residual palladium-plating solution for 5 minutes is described below.

First, the copper-clad laminate sample can be immersed in the residual nickel-phosphorus solution. Although the specific conditions for immersing the copper-clad laminate sample in the residual nickel-phosphorus plating solution are not particularly limited, for example, under the conditions of 65°C or more and 95°C or less, a copper-clad laminate sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters is immersed in 130 ml of the residual NPR-4 (Uemura) plating solution and plated for 15 minutes or more and 45 minutes or less. The cross-sectional area is the area of the cross section obtained by cutting the sample in a direction perpendicular to the direction in which the thickness of the sample increases.

If necessary, the sample may be immersed in a catalyst aqueous solution before being immersed in the nickel-phosphorus plating solution. Although the specific conditions are not particularly limited, for example, the sample may be immersed for 90 seconds under the conditions of 10°C or more and 40°C or less by using CATA NC-20 (MK Chemical & Technology Co., Ltd.) as a palladium catalyst.

At this time, the thickness of the nickel-phosphorus plated layer can be 3.9 μm or more, or 3.95 μm or more, or 3.9 μm or more and 4.0 μm or less, or 3.95 μm or more and 4.0 μm or less, and the nickel-phosphorus plated layer is obtained by immersing a film sample in which a photosensitive resin is stacked on a substrate in a nickel-phosphorus plated solution for 38 minutes and then immersing a copper-clad laminate sample in the remaining nickel-phosphorus plated solution for 28 minutes.

Next, the nickel-coated copper laminate samples can be immersed in the residual palladium plating solution to perform the coating. Although the specific conditions for immersing the nickel-phosphorus plated copper-coated laminate sample in the residual palladium plating solution are not particularly limited, for example, the plating can be performed by immersing a sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters in 130 ml of the residual TPD-21 (Uemura) plating solution for 2 minutes or more and 10 minutes or less at 30°C or more and 70°C or less.

At the same time, the palladium-plated copper-clad laminate samples can be immersed in the residual gold plating solution to perform plating. Although the specific conditions for immersing the palladium-plated copper-clad laminate sample in the residual gold plating solution are not particularly limited, for example, the plating can be performed by immersing a sample having a cross-sectional area of 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less, or 5 square centimeters in 130 ml of the residual TWX-40 (Uemura) plating solution for 5 minutes or more and 20 minutes or less at 65°C or more and 95°C or less.

At this time, the dry film photoresist has a characteristic that the thickness of the gold plating layer may be 0.11 microns or more, or 0.11 microns or more and 0.13 microns or less, or 0.12 microns or more, or 0.12 microns or more and 0.13 microns or less, and the gold plating layer is obtained by immersing a film sample in which a photosensitive resin layer of the dry film photoresist is stacked on a substrate in a gold plating solution for 98 minutes and then immersing a copper-clad laminate sample in the residual gold plating solution for 11 minutes.

That is, the dry film photoresist has a feature that the thickness of the gold plating layer may be 0.11 microns or more, or 0.11 microns or more and 0.13 microns or less, or 0.12 microns or more, or 0.12 microns or more and 0.13 microns or less, and the gold plating layer is obtained by immersing a film sample in which a photosensitive resin layer of the dry film photoresist is stacked on a substrate in a gold plating solution for 98 minutes and then immersing a copper-clad laminate sample in the residual gold plating solution for 11 minutes.

Meanwhile, the film sample in which the photosensitive resin containing the photosensitive resin composition is laminated on the substrate may be a laminate in which the photosensitive resin is laminated on any substrate. An example of the substrate may be a copper-clad laminate in which a copper layer having a thickness of 10 μm or more and 100 mm or less is provided on the surface.

The cross-sectional area of the film sample in which the photosensitive resin layer containing the photosensitive resin composition is stacked on the substrate can be 600 square centimeters or more and 700 square centimeters or less, or 640 square centimeters or more and 660 square centimeters or less, or 645 square centimeters or more and 655 square centimeters or less.

In addition, the cross-sectional area of the copper-clad laminate sample used for immersing the copper-clad laminate sample in the residual palladium plating solution for 5 minutes may be 1 square centimeter or more and 10 square centimeters or less, or 4 square centimeters or more and 6 square centimeters or less, or 4.5 square centimeters or more and 5.5 square centimeters or less.

When measuring the thickness of the palladium coating layer, exposure can be performed by irradiating ultraviolet light using an exposure device with an exposure dose of 20 mJ/cm2 or more and 200 mJ/cm2 or less, or 50 mJ/cm2 or more and 100 mJ/cm2 or less. The exposure time can be 1 second or more and 10 minutes or less, or 1 second or more and 10 seconds or less.

When measuring the thickness of the palladium-plated layer, development may be performed by using an alkaline aqueous solution having a concentration of 0.5 wt % or more and 1.5 wt % or less, or 0.9 wt % or more and 1.1 wt % or less. The pH of the alkaline aqueous solution may be in the range of 9 or more and 11 or less, and the temperature may be adjusted in accordance with the developability of the photosensitive resin layer. Specific examples of the alkaline aqueous solution include a sodium carbonate aqueous solution, a potassium carbonate aqueous solution, a sodium hydroxide aqueous solution, and the like.

The development can be carried out by a method of bringing an alkaline aqueous solution into contact with the photosensitive resin layer. As specific examples of the contact method, a spray method or an immersion method can be used. The development time can be 30 seconds or more and 10 minutes or less, or 30 seconds or more and 2 minutes or less.

The photosensitive resin layer may be in the form of a film without openings or in the form of a pattern with openings.

Examples of methods for forming a pattern-like photosensitive resin layer include a method of laminating a photosensitive resin layer of a dry film photoresist of another embodiment on a substrate and then performing exposure and development. In addition, a method of laminating a photosensitive resin layer of a photosensitive element according to another embodiment described later on a substrate and then performing exposure and development can be mentioned.

When the dry film photoresist or photosensitive element of another embodiment has a protective film on the photosensitive resin layer, a process of removing the protective film may be further performed before laminating the photosensitive resin layer on a circuit board or a display device manufacturing substrate.

In addition, when the dry film photoresist or photosensitive element of another embodiment has a polymer substrate or substrate film stacked on one side of the photosensitive resin layer, a process of removing the polymer substrate or substrate film immediately after the exposure process can be further performed. 3. Impedance Pattern

According to another embodiment of the present disclosure, a resistive pattern including a photosensitive resin pattern may be provided, wherein the photosensitive resin pattern contains a photosensitive resin composition contained in a dry film photoresist of another embodiment. Details regarding the photosensitive resin composition contained in the dry film photoresist include all the contents described above for one embodiment.

The photosensitive resin pattern may be a photosensitive resin composition in the form of a pattern having openings.

Examples of methods for forming a photosensitive resin pattern include a method of laminating a photosensitive resin layer of a dry film resist of another embodiment on a substrate and then performing exposure and development. In addition, a method of laminating a photosensitive resin layer of a photosensitive element according to one embodiment on a substrate and then performing exposure and development can be mentioned.

As the substrate, a copper-clad laminate, a glass substrate on which a transparent electrode such as ITO and indium zinc oxide (IZO) is sputtered or deposited, a similar film substrate, a glass substrate coated with a dielectric slurry, a silicon wafer, a glass wafer on which amorphous silicon is deposited, or a silicon wafer sputtered with a metal thin film such as copper, tantalum, or molybdenum.

For the exposure process, it is preferred to use UV, visible light, laser, and especially a laser direct exposure machine containing a light source with a wavelength of 350 nm to 410 nm, especially i-line (365 nm) or h-line (405 nm). In the case of using a laser direct exposure machine, when an ordinary light exposure machine is used under the condition of exposure energy of 3 mJ/cm2 to 15 mJ/cm2 or less than 15 mJ/cm2, it can work under the condition of exposure energy of 20 mJ/cm2 or less. Therefore, it can be used to produce images of PCB, lead frame, PDP and other display devices.

The developing process can be performed by immersion, spraying, atomization, brushing, etc. As the developing solution, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amine can be used.

When the dry film photoresist or photosensitive element of another embodiment has a protective film on the photosensitive resin layer, a process of removing the protective film can be performed before the process of laminating the photosensitive resin layer on the circuit board or display device manufacturing substrate.

In addition, when the dry film photoresist of the other embodiment or the photosensitive element of the one embodiment has a polymer substrate or substrate film stacked on one side of the photosensitive resin layer, a process of removing the polymer substrate or substrate film immediately after the exposure process may be further performed. 4. Circuit board, display device

According to another embodiment of the present disclosure, a circuit board or a display device may be provided, the circuit board or the display device including the impedance pattern of the another embodiment or a metal pattern formed by the impedance pattern of the another embodiment. Details about the impedance pattern include all the contents described above in the another embodiment.

The specific details of the circuit board or the display device are not particularly limited, and various conventionally known technical configurations can be applied without restriction.

The metal pattern may be formed from the above-mentioned impedance pattern. Specifically, the metal pattern may be formed by performing etching or plating through the opening included in the impedance pattern. That is, the metal pattern may include a lower metal remaining after etching the lower metal of the impedance pattern through the opening included in the impedance pattern, or a metal plated in the opening included in the impedance pattern.

Specifically, for example, by etching or plating the lower substrate exposed by the above-mentioned impedance pattern, a conductor pattern, a printed circuit board, a lead frame, an ITO electrode, a black mattress, a semiconductor bump, etc. can be manufactured. If necessary, after etching or plating, the patterned photosensitive resin layer can be peeled off from the substrate with an aqueous solution having a stronger alkalinity than the developer solution to be removed.

Thereby, by then performing a conventional etching/plating process using the dry film photoresist disclosed herein to form a circuit with a fine line width, and when generating images on a PCB with a fine line width as well as a lead frame, PDP, other display devices, and semiconductor devices by a known process, productivity can be maximized. [Beneficial Effects]

According to the present disclosure, a photosensitive element, a dry film photoresist, a resistive pattern, a circuit board, and a display device using the same can be provided. The photosensitive element can achieve the effect of reducing the contamination of the coating solution and allowing coating to be performed with sufficient thickness.

The present disclosure will be described in more detail by the examples shown below. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present invention thereto. < Preparation Example: Preparation of Alkaline Developable Binder Resin > Preparation Example 1

A 4-neck jacketed reaction flask was equipped with a mechanical stirrer and a reflux device, and then the inside of the flask was purged with nitrogen. 90 g of methyl ethyl ketone (MEK) and 10 g of methanol (MeOH) were added to the flask purged with nitrogen, and then 0.9 g of azobisisobutyronitrile (AIBN) was added and completely dissolved. A monomer mixture of 24 g of methacrylic acid (MAA), 6 g of methyl methacrylate (MMA), 30 g of styrene (SM), and 40 g of 2-phenoxyethyl methacrylate (PHEMA) was added as monomers, heated to 80° C., and then polymerized for 6 hours to prepare an alkaline developable binder resin (weight average molecular weight: 50,000 g/mol, solid content: 50.0 wt %, acid value: 155 mgKOH/g).

A specific example of the weight average molecular weight measurement conditions is as follows. The alkaline developable binder resin is dissolved in tetrahydrofuran so that its concentration in THF is 1.0 (w/w)% (about 0.5 (w/w)% in terms of solid content), filtered using a syringe filter having a pore size of 0.45 μm, and then injected into the GPC in an amount of 20 μl. Tetrahydrofuran (THF) is used as the mobile phase of the GPC, and it is allowed to flow at a flow rate of 1.0 ml/min. The column consisted of an Agilent PLgel 5 μm guard column (7.5 mm×50 mm) and two Agilent PLgel 5 μm mixed D columns (7.5 mm×300 mm) connected in series, and the measurement was performed at 40°C using an Agilent 1260 Infinity II system and an RI detector.

The acid value was measured by sampling 1 g of the alkaline developable binder resin, dissolving it in 50 ml of a mixed solvent (MeOH 20%, acetone 80%), adding two drops of 1% phenolphthalein indicator, and titrating with 0.1N-KOH.

Based on the weight of the alkaline developable binder resin prepared in the above Preparation Example, the solid content was measured as the weight percent of solids remaining after heating in an oven at 150°C for 120 minutes. Preparation Example 2

The four-neck round bottom flask was equipped with a mechanical stirrer and a reflux device, and then the inside of the flask was purged with nitrogen. 80 g of methyl ethyl ketone (MEK) and 7.5 g of methanol (MeOH) were added to the flask purged with nitrogen, and then 0.45 g of azobisisobutyronitrile (AIBN) was added and completely dissolved. A monomer mixture of 8 g (0.11 mol, 10.91 mol% of 100 mol% of all monomers) of acrylic acid (AA), 15 g (0.17 mol, 17.13 mol% of 100 mol% of all monomers) of methacrylic acid (MAA), 15 g (0.12 mol, 11.50 mol% of 100 mol% of all monomers), 52 g (0.52 mol, 51.03 mol% of 100 mol% of all monomers) of methyl methacrylate (MMA), and 10 g (0.10 mol, 9.43 mol% of 100 mol% of all monomers) of styrene (SM) was added as monomers, heated to 80°C, and then polymerized for 6 hours to prepare an alkali developable adhesive resin.

The alkaline developable binder resin was measured to have a weight average molecular weight of 71,538 g/mol, a glass transition temperature of 79° C., a solid content of 51.4 wt %, and an acid value of 156.3 mg KOH/g.

The four-neck round bottom flask was equipped with a mechanical stirrer and a reflux device, and then the inside of the flask was purged with nitrogen. 110 g of methyl ethyl ketone (MEK) and 10 g of methanol (MeOH) were added to the flask purged with nitrogen, and then 1 g of azobisisobutyronitrile (AIBN) was added and completely dissolved. A monomer mixture of 30 g (0.35 mol, 21.32 mol% of 100 mol% of all monomers) of methacrylic acid (MAA), 100 g (1.00 mol, 61.07 mol% of 100 mol% of all monomers) of methyl methacrylate (MMA), and 30 g (0.29 mol, 17.61 mol% of 100 mol% of all monomers) of styrene (SM) was added thereto as monomers, heated to 80°C, and then polymerized for 6 hours to prepare an alkaline developable binder resin (weight average molecular weight: 49,852 g/mol, glass transition temperature: 125°C, solid content: 48.5 wt%, and acid value: 163.17 mgKOH/g). Preparation Example 4

The four-neck round bottom flask was equipped with a mechanical stirrer and a reflux device, and then the inside of the flask was purged with nitrogen. 90 g of methyl ethyl ketone (MEK) and 10 g of methanol (MeOH) were added to the flask purged with nitrogen, and then 0.85 g of azobisisobutyronitrile (AIBN) was added and completely dissolved. A monomer mixture of 25 g (0.29 mol, 30.86 mol% of 100 mol% of all monomers) of methacrylic acid (MAA), 20 g (0.20 mol, 21.22 mol% of 100 mol% of all monomers), 25 g (0.24 mol, 25.50 mol% of 100 mol% of all monomers) of styrene (SM) and 30 g (0.21 mol, 22.42 mol% of 100 mol% of all monomers) of glycidyl methacrylate (GMA) was added as a monomer, heated to 80°C, and then polymerized for 6 hours to prepare an alkali developable adhesive resin.

The alkaline developable binder resin was measured to have a weight average molecular weight of 55,201 g/mol, a glass transition temperature of 112°C, a solid content of 50.2 wt%, and an acid value of 162.0 mg KOH/g. < Examples and Comparative Examples: Preparation of Photosensitive Resin Compositions and Dry Film Photoresists >

According to the composition shown in Table 1 below, a photopolymerization initiator was dissolved in methyl ethyl ketone (MEK) as a solvent, and then a photopolymerizable compound and an alkaline developable binder resin were added and mixed for about 1 hour using a mechanical stirrer to prepare a photosensitive resin composition.

The obtained photosensitive resin composition was coated on a 19-micrometer PET film using a coating rod to form a photosensitive resin composition layer, and then dried using a hot air oven. At this time, the drying temperature was 80° C., the drying time was 5 minutes, and the thickness of the photosensitive resin composition layer after drying was 40 micrometers.

A protective film (polyethylene) layer is laminated on a dry photosensitive resin composition layer to prepare a dry film photoresist. [Table 1] Components Product Name (or Component Name) Content (wt.%) Example 1 Example 2 Example 3 Comparison Example 1 Alkaline developable adhesive resin Preparation Example 1 65.0 65.0 65.0 65.0 Photopolymerizable compounds M241 4.0 4.0 4.0 5.0 M2101 16.0 16.0 16.0 20.0 M500 5.0 0 2.5 0 Viscoat #802 0 5.0 2.5 0 Photopolymerization initiator EAB 0.05 0.05 0.05 0.05 BCIM 1.30 1.30 1.30 1.30 Additives Toluenesulfonic acid monohydrate (Aldrich Chemical) 0.044 0.044 0.044 0.044 N,N-BDA 0.066 0.066 0.066 0.066 Colorless crystal violet (Hodogaya Co., Japan) 0.170 0.170 0.170 0.170 Diamond Green GH (Hodogaya Co., Ltd., Japan) 0.015 0.015 0.015 0.015 Solvent MEK (Methyl Ethyl Ketone) 8.355 8.355 8.355 8.355 (1) M241: Bisphenol A (EO) ₄ dimethacrylate (Meiyuan Specialty Chemical Co., Ltd.) (2) M2101: Bisphenol A (EO) ₁₀ dimethacrylate (Meiyuan Specialty Chemical Co., Ltd.) (3) M500: Dipentaerythritol pentaacrylate (Mw 524, Meiyuan Specialty Chemical Co., Ltd.) (4) Viscoat#802: Tripentaerythritol acrylate (Mw 805, Osaka Yuki) J is hydrogen or acryloyl, j is a mixture of 10% to 20% of a compound with j = 1, 55% to 65% of a compound with j = 2, and 5% to 15% of a compound with j = 3 (5) EAB: 4,4'-(bis(diethylamino)benzophenone) (Aldrich Chemical Company) (6) BCIM: 2,2'-bis-(2-chlorophenyl)-4,5,4',5'-tetraphenylbisimidazole (Aldrich Chemical Company) (7) N,N-BDA: N,N-benzyldimethylamide [Table 2] Components Product Name (or Component Name) Content (wt.% of each component based on 100 wt.% of photosensitive resin composition) Example 4 Example 5 Comparison Example 2 Alkaline developable adhesive resin Preparation Example 1 50.0 (76.92 wt.% based on 100 wt.% of binder resin) 30.0 (46.15 wt.% based on 100 wt.% of binder resin) - Preparation Example 2 1.0 (1.54 wt.% based on 100 wt.% of binder resin) 1.0 (1.54 wt.% based on 100 wt.% of binder resin) 7.6 Preparation Example 3 7.5 (11.54 wt.% based on 100 wt.% of binder resin) 7.5 (11.54 wt.% based on 100 wt.% of binder resin) 57.4 Preparation Example 4 6.5 (10.00 wt.% based on 100 wt.% of binder resin) 26.5 (40.77 wt.% based on 100 wt.% of binder resin) - Total 65.0 65.0 65.0 Photopolymerizable compounds M241 5.0 5.0 5.0 M2101 20.0 20.0 20.0 Total 25.0 25.0 25.0 Photopolymerization initiator EAB 0.05 0.05 0.05 BCIM 1.30 1.30 1.30 Total 1.35 1.35 1.35 Additives Toluenesulfonic acid monohydrate (Aldrich Chemical Company) 0.044 0.044 0.044 N,N-BDA 0.066 0.066 0.066 Colorless crystal violet (Hodogaya Co., Ltd., Japan) 0.170 0.170 0.170 Diamond Green GH (Hodogaya Co., Ltd., Japan) 0.015 0.015 0.015 Total 0.295 0.295 0.295 Solvent MEK (Methyl Ethyl Ketone) 8.355 8.355 8.355 (1) M241: Bisphenol A (EO) ₄ dimethacrylate (Meiyuan Specialty Chemical Co., Ltd.) (2) M2101: Bisphenol A (EO) ₁₀ dimethacrylate (Meiyuan Specialty Chemical Co., Ltd.) (3) EAB: 4,4'-(bis(diethylamino)benzophenone) (Aldrich Chemical Company) (4) BCIM: 2,2'-bis-(2-chlorophenyl)-4,5,4',5'-tetraphenylbisimidazole (Aldrich Chemical Company) (5) N,N-BDA: N,N-benzyl dimethyl amide ＜ Experimental example ＞

The physical properties of the dry film photoresists prepared in the examples and comparative examples were measured by the following methods, and the results are shown in Tables 3 and 4 below. 1. Contamination properties of electroless palladium plating solution

The protective film was peeled off from the dry film photoresist prepared in the examples and comparative examples, and a photosensitive resin layer of HAKUTO MACH 610i double-sided laminated dry film photoresist was used to contact the copper layer surface of a 1.6 mm thick copper-clad laminate, and was subjected to brushing treatment under the conditions of a substrate preheating roll temperature of 120°C, a laminating machine roll temperature of 115°C, a roll pressure of 4.0 kgf/cm2, and a roll speed of 2.0 min/m, thereby forming a laminate.

The supporting PET film for dry film photoresist was peeled off from the laminate, and then the entire surface was exposed with UV light for 4 seconds at an exposure dose of 80 mJ/cm2 by ORC EXM-1201-F (parallel light exposure machine) using a photomask, and then allowed to stand for 15 minutes. Subsequently, development was performed with a 1.0 wt% Na ₂ CO ₃ aqueous solution at 30±1°C for one minute under a jet type development condition with a jet pressure of 1.5 kgf/cm2. The developed laminate was baked in an oven at 140°C for 30 minutes.

After the baked stack was fully cooled, samples with a cross-sectional area of 650 cm2 were prepared. The samples were immersed in 130 ml of CATA NC-20 (MK Chemical & Technology) palladium catalyst at 25°C for 1 min 30 s, rinsed in distilled water for 1 min, immersed in 130 ml of NPR-4 (Uemura) nickel-phosphorus plating solution at 80±2°C for 38 min, rinsed in distilled water for 1 min, immersed in 130 ml of TPD-21 (Uemura) palladium plating solution at 55±2°C for 60 min, rinsed in distilled water for 1 min, immersed in 130 ml of TWX-40 (Uemura) gold plating solution at 80±2°C for 98 min, and rinsed in distilled water for 1 min.

Then, in the coating solution in which the dry film photoresist component was washed off by immersing the laminate, the copper-clad laminate samples with a cross-sectional area of 5 cm2 and a thickness of 1.6 mm that had been subjected to the brushing treatment were sequentially immersed in 130 ml of CATA NC-20 (MK Chemical & Technology) palladium catalyst for 1 minute 30 seconds, rinsed in distilled water for 1 minute, immersed in 130 ml NPR-4 (Uemura) nickel-phosphorus plating solution at 80±2°C for 28 minutes, rinsed in distilled water for 1 minute, immersed in 130 ml TPD-21 (Uemura) palladium plating solution at 55±2°C for 5 minutes, rinsed in distilled water for 1 minute, immersed in 130 ml TWX-40 (Uemura) gold plating solution at 80±2°C for 11 minutes, and rinsed in distilled water for 1 minute.

The coating thickness of nickel-phosphorus, palladium and gold-copper-plated laminates was measured in sequence using the Helmut Fischer XDV-μ, and the contamination properties of the coating solution were evaluated by the degree of coating thickness. 2. Fine wire adhesion (unit: micrometer)

The protective film was peeled off from the dry film photoresist prepared in the examples and comparative examples, and the photosensitive resin layer of HAKUTO MACH 610i dry film photoresist was used to contact the copper layer surface of a 1.6 mm thick copper-clad laminate and subjected to brushing treatment under the following conditions: a substrate preheating roll temperature of 120°C, a laminator roll temperature of 115°C, a roll pressure of 4.0 kgf/cm2, and a roll speed of 2.0 min/m, thereby forming a laminate.

The supporting PET film for dry film photoresist was peeled off from the laminate, and then the entire surface was exposed by UV irradiation for 4 seconds at an exposure dose of 80 mJ/cm2 using a photomask by ORC EXM-1201-F (parallel light exposure machine), and then allowed to stand for 15 minutes. Subsequently, development was performed with a 1.0 wt% _Na2CO3 aqueous solution at 30±1°C for one minute under a jet type developing condition with a jet pressure of 1.5 kgf/ _cm2 .

In the developed laminate, the minimum line width of the photosensitive resin layer was measured using a ZEISS AXIOPHOT microscope and evaluated as fine line adhesion. It can be evaluated that the smaller this value is, the better the fine line adhesion is. 3. 1 :1 resolution (unit: micron)

The protective film was peeled off from the dry film photoresist prepared in the examples and comparative examples, and the photosensitive resin layer of HAKUTO MACH 610i dry film photoresist was used to contact the copper layer surface of a 1.6 mm thick copper-clad laminate, and was subjected to brushing treatment under the following conditions: a substrate preheating roll temperature of 120°C, a laminator roll temperature of 115°C, a roll pressure of 4.0 kgf/cm2, and a roll speed of 2.0 min/m, thereby forming a laminate.

The supporting PET film for dry film photoresist was peeled off from the laminate, and then irradiated with UV light for 4 seconds using an ORC EXM-1201-F (parallel light exposure machine) through a photomask for circuit evaluation at an exposure dose of 80 mJ/cm2 so that the width of the circuit line and the space interval between the circuit lines could become 1:1, and then allowed to stand for 15 minutes. Subsequently, development was performed with a 1.0 wt% Na ₂ CO ₃ aqueous solution at 30±1°C for one minute under a jet-type developing condition with a jet pressure of 1.5 kgf/cm2.

In the developed laminate, the minimum spacing between the photosensitive resin layers was measured using a ZEISS AXIOPHOT microscope and evaluated as 1:1 resolution. It can be evaluated that the smaller this value is, the better the 1:1 resolution value is. 4. Peeling rate (unit: second)

The protective film was peeled off from the dry film photoresist prepared in the examples and comparative examples, and the photosensitive resin layer of HAKUTO MACH 610i dry film photoresist was used to contact the copper layer surface of a 1.6 mm thick copper-clad laminate and subjected to brushing treatment under the following conditions: a substrate preheating roll temperature of 120°C, a laminator roll temperature of 115°C, a roll pressure of 4.0 kgf/cm2, and a roll speed of 2.0 min/m, thereby forming a laminate.

The supporting PET film for dry film photoresist was peeled off from the laminate, and then irradiated with ultraviolet light using an ORC EXM-1201-F (parallel light exposure machine) through a photomask for circuit evaluation until an exposure dose of 40 mJ/cm2 was reached, and then allowed to stand for 15 minutes. Subsequently, development was performed with a 1.0 wt% Na ₂ CO ₃ aqueous solution at 30±1°C for twice the minimum development time under a jet-type development condition with a jet pressure of 1.5 kgf/cm2.

Then, the photosensitive resin layer was peeled off from the copper-coated laminate using a 3% sodium hydroxide aqueous solution (temperature 50°C). At this time, the time required for the photosensitive resin layer to fall off from the copper-coated laminate was measured. [Table 3] Category Pollution properties of electroless palladium plating solutions Fine line adhesion (μm) 1:1 resolution (μm) Peeling rate (seconds) Nickel-phosphorus coating thickness (μm) Palladium plating thickness (μm) Gold plating thickness (μm) Example 1 3.926 0.138 0.112 14 12 200 Example 2 3.976 0.101 0.105 14 12 180 Example 3 3.905 0.100 0.121 14 12 190 Comparison Example 1 3.718 0.008 0.111 14 12 150

As shown in Table 3, it can be confirmed that in Examples 1 to 3, the palladium plating thickness was measured to be 0.1 micrometers or more and 0.138 micrometers or less, and thus the plating level was sufficiently improved by palladium compared to Comparative Example 1 in which the plating thickness was 0.008 micrometers. In addition, it can be confirmed that in Examples 1 to 3, the nickel-phosphorus plating thickness was measured to be 3.905 micrometers or more and 3.976 micrometers or less, and thus the plating level was sufficiently improved even by using nickel-phosphorus compared to Comparative Example 1 in which the plating thickness was 3.718 micrometers.

Thus, it was confirmed that the dry film photoresists prepared in Examples 1 to 3 had low contamination properties to the coating solution, and therefore a sufficient level of coating properties could be ensured even when the coating solution was reused. [Table 4] Category Pollution properties of electroless palladium plating solutions Fine line adhesion (μm) 1:1 resolution (μm) Peeling rate (seconds) Nickel-phosphorus coating thickness (μm) Palladium plating thickness (μm) Gold plating thickness (μm) Example 4 3.916 0.121 0.112 14 12 81 Example 5 3.926 0.113 0.122 18 16 66 Comparison Example 2 3.863 0.002 0.100 18 16 102

As shown in Table 4, it can be confirmed that in Examples 4 to 5, the palladium plating thickness was measured to be 0.113 micrometers or more and 0.121 micrometers or less, and thus the plating level was sufficiently improved by palladium compared to Comparative Example 2 in which the plating thickness was 0.002 micrometers. In addition, it can be confirmed that in Examples 4 to 5, the nickel-phosphorus plating thickness was measured to be 3.916 micrometers or more and 3.926 micrometers or less, and thus the plating level was sufficiently improved even by using nickel-phosphorus compared to Comparative Example 2 in which the plating thickness was 3.863 micrometers.

Furthermore, it was confirmed that in Examples 4 to 5, the gold plating thickness was measured to be 0.112 μm or more and 0.122 μm or less, and thus the plating level was sufficiently improved even when gold was used, compared to Comparative Example 2 in which the plating thickness was 0.100 μm.

From the above results, it was confirmed that the dry film photoresist prepared in Examples 4 and 5 was low in contamination properties to the coating solution, and therefore a sufficient level of coating properties could be ensured even when the coating solution was reused.

In addition, the dry film photoresists prepared in Examples 4 and 5 exhibited short stripping times of 66 seconds or more and 81 seconds or less, thereby implementing excellent stripping properties.

without

without

Claims (18)

A photosensitive element, comprising: a polymer substrate; and a photosensitive resin layer formed on the polymer substrate, wherein the thickness of the palladium-plated layer is 0.01 micrometers or more, and the palladium-plated layer is obtained by immersing a film sample in which the photosensitive resin layer is stacked on a copper-clad laminate in a palladium-plated solution for 60 minutes and then immersing a new copper-clad laminate sample in the remaining palladium-plated solution for 5 minutes, wherein the photosensitive resin layer is formed on the polymer substrate, wherein the thickness of the palladium-plated layer is 0.01 micrometers or more, and the palladium-plated layer is obtained by immersing a film sample in which the photosensitive resin layer is stacked on a copper-clad laminate for 60 minutes and then immersing a new copper-clad laminate sample in the remaining palladium-plated solution for 5 minutes. The resin layer contains a photosensitive resin composition, which includes an alkaline developable adhesive resin, a photopolymerization initiator, and a photopolymerizable compound, wherein the photopolymerizable compound includes at least one selected from the group consisting of a penta-type (meth)acrylate compound having five (meth)acrylic groups and a multifunctional (meth)acrylate compound having seven or more (meth)acrylic groups. The photosensitive element as claimed in claim 1, wherein: the photosensitive element has a further feature that the thickness of the nickel-phosphorus plated layer is 3.9 microns or greater, and the nickel-phosphorus plated layer is obtained by immersing the film sample in which the photosensitive resin layer is stacked on the copper-clad laminate in a nickel-phosphorus plated solution for 38 minutes and then immersing a new copper-clad laminate sample in the remaining nickel-phosphorus plated solution for 28 minutes. The photosensitive element as described in claim 1, wherein: the five-type (meth)acrylate compound further contains a hydroxyl group. The photosensitive element as claimed in claim 1, wherein: the five-type (meth)acrylate compound is a compound represented by the following chemical formula A:

In the chemical formula A, five of _T1 to _T6 are the same as or different from each other and are each independently a (meth)acryloyl group, and the remaining one is hydrogen. The photosensitive element as claimed in claim 1, wherein: the multifunctional (meth)acrylate compound is a compound represented by the following chemical formula B: [Chemical formula B]

Wherein, in Formula B, _T7 to _T11 are each independently a (meth)acryl group, _T12 is hydrogen or a (meth)acryl group, and t is an integer from 2 to 10. A photosensitive element, comprising: a polymer substrate; and a photosensitive resin layer formed on the polymer substrate, wherein the thickness of the palladium-plated layer is 0.01 micrometer or greater, and the palladium-plated layer is obtained by immersing a film sample in which the photosensitive resin layer is stacked on a copper-clad laminate in a palladium-plated solution for 60 minutes and then immersing a new copper-clad laminate sample in the remaining palladium-plated solution for 5 minutes, and the photosensitive resin layer contains a photosensitive resin composition, and the photosensitive resin composition includes an alkaline developable binder resin, a photopolymerization initiator, and a photopolymerizable compound, wherein the alkaline developable binder resin includes four or more polymers that are different from each other. The photosensitive element of claim 6, wherein: the alkaline developable binder resin comprises a first binder resin, the first binder resin comprising the following repeating units represented by Chemical Formula 1:

Wherein, in Chemical Formula 1, _R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, _R2 is an alkylene group having 1 to 10 carbon atoms, Ar is an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 20. The photosensitive element of claim 7, wherein: in addition to the repeating unit represented by chemical formula 1, the first binder resin further includes the repeating unit represented by chemical formula 2, the repeating unit represented by chemical formula 3, and the repeating unit represented by chemical formula 4: [Chemical formula 2]

Wherein, in Chemical Formula 2, R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms,

Wherein, in Chemical Formula 3, _R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and _R5 is an alkyl group having 1 to 10 carbon atoms, and [Chemical Formula 4]

In Chemical Formula 4, Ar is an aromatic group having 6 to 20 carbon atoms. The photosensitive element of claim 6, wherein: the alkaline developable binder resin includes a second binder resin, the second binder resin contains the following repeating units represented by chemical formula 5:

Wherein, in Chemical Formula 5, _R6 is hydrogen, and _R7 is an alkyl group having 1 to 10 carbon atoms. The photosensitive element of claim 9, wherein: in addition to the repeating unit represented by chemical formula 5, the second binder resin further includes the repeating unit represented by chemical formula 6, the repeating unit represented by chemical formula 7, the repeating unit represented by chemical formula 8, and the repeating unit represented by chemical formula 9:

Wherein, in chemical formula 6, R ₈ is hydrogen,

Wherein, in Chemical Formula 7, R ₉ is an alkyl group having 1 to 10 carbon atoms,

Wherein, in Chemical Formula 8, R ₁₀ is an alkyl group having 1 to 10 carbon atoms, and R ₁₁ is an alkyl group having 1 to 10 carbon atoms,

In Chemical Formula 9, Ar is an aromatic group having 6 to 20 carbon atoms. The photosensitive element of claim 6, wherein: the alkaline developable binder resin includes a third binder resin, the third binder resin contains the following repeating unit represented by chemical formula 10, the following repeating unit represented by chemical formula 11, and the following repeating unit represented by chemical formula 12:

Wherein, in Chemical Formula 10, R ₉ is an alkyl group having 1 to 10 carbon atoms,

Wherein, in Chemical Formula 11, R ₁₀ is an alkyl group having 1 to 10 carbon atoms, and R ₁₁ is an alkyl group having 1 to 10 carbon atoms, and [Chemical Formula 12]

In Chemical Formula 12, Ar is an aromatic group having 6 to 20 carbon atoms. The photosensitive element of claim 6, wherein: the alkaline developable binder resin includes a fourth binder resin, and the fourth binder resin contains the following repeating units represented by Chemical Formula 13:

Wherein, in Chemical Formula 13, R ₁₂ is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R ₁₃ is an alkylene group having 1 to 10 carbon atoms. The photosensitive element of claim 12, wherein: in addition to the repeating unit represented by chemical formula 13, the fourth binder resin further includes the repeating unit represented by chemical formula 14, the repeating unit represented by chemical formula 15, and the repeating unit represented by chemical formula 16:

Wherein, in Chemical Formula 14, R ₁₄ is hydrogen or an alkyl group having 1 to 10 carbon atoms,

Wherein, in Chemical Formula 15, R ₁₅ is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R ₁₆ is an alkyl group having 1 to 10 carbon atoms,

In Chemical Formula 16, Ar is an aromatic group having 6 to 20 carbon atoms. A dry film photoresist comprises: a photosensitive resin composition, comprising an alkaline developable adhesive resin, a photopolymerization initiator and a photopolymerizable compound, wherein the photopolymerizable compound comprises a penta-type (meth)acrylate compound having five (meth)acrylic groups and a multifunctional (meth)acrylate compound having seven or more (meth)acrylic groups. At least one of the groups, wherein the dry film photoresist has a feature of a palladium coating layer having a thickness of 0.01 micrometer or greater, the palladium coating layer being obtained by immersing a film sample in which a photosensitive resin layer of the dry film photoresist is laminated on a copper-clad laminate in a palladium coating solution for 60 minutes and then immersing a new copper-clad laminate sample in the remaining palladium coating solution for 5 minutes. A dry film photoresist, comprising: a photosensitive resin composition, including an alkaline developable binder resin, a photopolymerization initiator and a photopolymerizable compound, wherein the alkaline developable binder resin comprises four or more polymers different from each other, and wherein the dry film photoresist has a characteristic of a palladium coating layer having a thickness of 0.01 micrometer or more, and the palladium coating layer is obtained by immersing a film sample in which the photosensitive resin layer of the dry film photoresist is stacked on a copper-clad laminate in a palladium coating solution for 60 minutes and then immersing a new copper-clad laminate sample in the residual palladium coating solution for 5 minutes. A resist pattern, comprising a photosensitive resin pattern, wherein the photosensitive resin pattern contains the photosensitive resin composition contained in the dry film photoresist as described in claim 14 or 15. A circuit board comprising an impedance pattern as described in claim 16, or a metal pattern formed by the impedance pattern as described in claim 16. A display device includes the impedance pattern as described in claim 16, or a metal pattern formed by the impedance pattern as described in claim 16.