WO2019155819A1 - Photosensitive composition and use thereof - Google Patents

Abstract

The present invention discloses a photosensitive composition containing a conductive powder, a photopolymerizable compound, and a photopolymerization initiator. The photopolymerization initiator contains at least two components: (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; and (2) an α-aminoalkylphenone. The 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide occupies 50% by mass relative to 100% by mass of the photopolymerization initiator.

Description

Photosensitive composition and use thereof

The present invention relates to a photosensitive composition and use thereof.
Note that this application claims priority based on Japanese Patent Application No. 2018-021134 filed on Feb. 8, 2018, the entire contents of which are incorporated herein by reference. Yes.

Conventionally, a method of forming a conductive layer or a resin insulating layer on a substrate by photocuring using a photosensitive composition containing a photopolymerizable compound and a photopolymerization initiator is known (Patent Documents 1 to 4). 6). For example, Patent Document 1 discloses that a wiring pattern is formed on a substrate by a photolithography method including a film-form forming step, an exposure step, a development step, and a baking step. In such a method, first, in the step of forming a film-like body, the photosensitive composition is applied onto the substrate by a printing method or the like and dried to form the film-like body. Next, in the exposure step, after the formed film-like body is covered with a photomask having a predetermined opening pattern, the film-like body is exposed through the photomask. Thereby, the exposed portion of the film-like body is photocured. Next, in the development process, the unexposed portion that has been shielded from light by the photomask is removed by corrosion with an alkaline etching solution. And the film-like body used as the desired development pattern is baked in a baking process. According to this method, it is possible to form a conductive layer having a high-definition pattern as compared with various conventional printing methods.

Japanese Patent No. 4437603 Japanese Patent No. 4095163 Japanese Patent Application Publication No. 2003-183401 Japanese Patent Application Publication No. 2015-110745 Japanese Patent Application Publication No. 2015-184631 Japanese Patent No. 5393402

By the way, in recent years, various electronic devices are rapidly becoming smaller and higher performance, and further miniaturization and higher density are demanded for electronic components mounted on the electronic devices. Along with this, in the manufacture of electronic components, there is a demand for thinning (narrowing) as well as reducing the resistance of the conductive layer. For example, it is required to form a conductive layer including a thin wire having a line width of 30 μm or less (hereinafter sometimes referred to as “fine line”).

However, according to the study by the present inventors, it was difficult to stably form a fine line when a conventional photosensitive composition as described in the above-mentioned patent document was used. For example, an unexposed portion cannot be completely removed in the development process, and adjacent wirings are connected to each other, thereby causing a short circuit defect. In addition, if the development process time is set to be long in order to suppress the occurrence of such short-circuit defects, the exposed portion may be narrowed, and the development pattern may be peeled off or disconnected.

One possible cause of the above problem is a short development margin. Here, the “development margin” is a defect such as peeling or disconnection from the point where the unexposed portion is completely removed (break point (BP)) in the developing process to the exposed portion constituting the developed pattern. It represents the length of time until the occurrence of. That is, if the development margin is not sufficiently secured, the exposed portion is thinned or lost immediately after the unexposed portion is removed. For this reason, it is difficult to determine the timing to end the development process, particularly when a fine line is formed. Therefore, in the process management, there is a demand for a technique capable of ensuring a long development margin (for example, 10 seconds or more) and forming a fine line with good reproducibility.

The present invention has been made in view of such points, and an object thereof is to provide a photosensitive composition having a long development margin and capable of stably forming a fine line. Another related object is to provide a composite comprising a conductive film made of a dried body of such a photosensitive composition. Another related object is to provide an electronic component including a conductive layer made of a fired body of such a photosensitive composition and a method for producing the same.

According to the present invention, there is provided a photosensitive composition used for producing a conductive layer including a wiring having a line width of 30 μm or less. This photosensitive composition contains a conductive powder, a photopolymerizable compound, and a photopolymerization initiator. The photopolymerization initiator includes at least the following two components: (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; (2) α-aminoalkylphenones; The above (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide accounts for 50% by mass or more when the total amount of the agent is 100% by mass.

The photosensitive composition contains at least two components (1) and (2) as a photopolymerization initiator. As a result, it is possible to ensure a long development margin time in the development process and improve the fine line formability of the exposed portion. As a result, even a fine line having a line width of 30 μm or less can be formed with good reproducibility. In addition, it is possible to improve the yield by suppressing the occurrence of defects such as short circuit failure, peeling, and disconnection.

In a preferred embodiment disclosed herein, the mass ratio of (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide to (2) α-aminoacetophenone is 50:50 to 90: 10. As a result, the fine line formability can be improved and the effects of the technology disclosed herein can be exhibited at a higher level. For example, even a conductive layer with a finer line can be formed with high accuracy.

In a preferred embodiment disclosed herein, the mass ratio of (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide to (2) α-aminoacetophenone is 50:50 to 85: 15. As a result, the etching resistance of the exposed portion can be improved and the peeling of the conductive layer can be suppressed at a higher level.

In a preferred embodiment disclosed herein, the proportion of the photopolymerization initiator is 2% by mass or less when the entire photosensitive composition is 100% by mass. As a result, at least one of the effect of ensuring a longer development margin time and the effect of improving the fine line formability is achieved.

In a preferred embodiment disclosed herein, the photopolymerizable compound includes a photopolymerizable compound having a urethane bond. By this, the electrically conductive film which consists of a dried body of a photosensitive composition can be made excellent in a softness | flexibility and a stretching property. In addition, the etching resistance of the exposed portion can be improved. As a result, the adhesion between the base material and the conductive layer can be improved, and the occurrence of defects such as peeling can be suppressed at a higher level.

In a preferred embodiment disclosed herein, the conductive powder includes silver-based particles. As a result, a conductive layer having an excellent balance between cost and low resistance can be realized.

In a preferable aspect disclosed herein, the conductive powder includes a core portion including a core portion including a metal material, and a covering portion that covers at least a part of the surface of the core portion and includes a ceramic material. Including. As a result, the etching resistance of the exposed portion can be further improved, and the fine line formability can be further improved. In addition, in applications that produce ceramic electronic components with a conductive layer on a ceramic substrate (ceramic substrate), the integrity of the ceramic substrate and the conductive layer is increased to improve the durability of the ceramic electronic component. can do.

In a preferred embodiment disclosed herein, the lightness L ^* of the conductive powder is 50 or more in the L ^* a ^* b ^* color system based on Japanese Industrial Standard JIS Z 8781: 2013. Thus, in the exposure process, light can stably reach the deep part of the exposed part, and a thick conductive layer can also be realized stably.

In a preferred embodiment disclosed herein, the photosensitive composition further includes an organic solvent having a boiling point of 150 ° C. or higher and 250 ° C. or lower. This improves the storage stability of the photosensitive composition and the handleability during formation of the conductive film, and can keep the drying temperature after printing low.

Further, according to the present invention, there is provided a composite comprising a green sheet and a conductive film which is disposed on the green sheet and is made of a dried body of the photosensitive composition.

Further, according to the present invention, an electronic component including a conductive layer made of a fired body of the photosensitive composition is provided. According to the said photosensitive composition, a fine line can be implement | achieved stably. For this reason, the electronic component provided with the small and / or high-density conductive layer can be suitably realized.

Further, according to the present invention, the method includes applying the photosensitive composition onto a substrate, exposing and developing, then firing, and forming a conductive layer composed of a fired body of the photosensitive composition. A method for manufacturing a component is provided. The photosensitive composition has a long development margin. Therefore, by such a manufacturing method, an electronic component having a small and / or high-density conductive layer can be stably manufactured, and the yield can be improved.

FIG. 1 is a cross-sectional view schematically showing the structure of a multilayer chip inductor according to an embodiment. FIG. 2 is a graph showing the relationship between the content ratio of the initiator c and the line width of the wiring pattern.

Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than matters specifically mentioned in the present specification (for example, photopolymerization initiator contained in the photosensitive composition) and matters necessary for carrying out the present invention (for example, a method for preparing the photosensitive composition, A method for forming a conductive film and a conductive layer, a method for manufacturing an electronic component, etc.) can be understood based on the technical contents taught by this specification and general technical common knowledge of those skilled in the art. . The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

In the following description, the photosensitive composition is a film-like body (dried at a temperature below the boiling point of the photopolymerizable compound and the photopolymerization initiator, specifically about 200 ° C. or less, for example, 100 ° C. or less. Is referred to as a “conductive film”. The conductive film includes all unfired (before firing) film-like bodies. The conductive film may be an uncured product before photocuring or a cured product after photocuring. In the following description, a sintered body (baked product) obtained by firing the photosensitive composition at a temperature equal to or higher than the sintering temperature of the conductive powder is referred to as a “conductive layer”. The conductive layer includes a wiring (linear body) and a wiring pattern.
In addition, the notation “A to B” indicating a range in the present specification means A or more and B or less.

≪Photosensitive composition≫
The photosensitive composition disclosed here is used for producing a conductive layer including fine line wiring having a line width (line width) of 30 μm or less after firing. For example, it is preferably used for forming a conductor film including a portion having a line width (line width) of 30 μm or less. The photosensitive composition disclosed here contains a conductive powder, a photopolymerizable compound, and a photopolymerization initiator as essential components. Hereinafter, each component will be described in order.

<Conductive powder>
An electroconductive powder is a component which provides electroconductivity to the electroconductive layer obtained by baking a photosensitive composition. It does not specifically limit as electroconductive powder, According to a use etc. from a conventionally well-known thing, 1 type (s) or 2 or more types can be suitably selected and used, for example. As a preferred example of the conductive powder, gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), aluminum (Al), nickel (Ni), ruthenium (Ru), rhodium (Rh), tungsten (W), iridium (Ir), a simple substance of metal such as osmium (Os), and a mixture or alloy thereof. Examples of the alloy include silver alloys such as silver-palladium (Ag—Pd), silver-platinum (Ag—Pt), and silver-copper (Ag—Cu).

In a preferred embodiment, the conductive powder contains silver-based particles. Silver is relatively cheap and has high electrical conductivity. For this reason, when the conductive powder contains silver-based particles, a conductive layer excellent in balance between cost and low resistance can be realized. In the present specification, “silver-based particles” include all particles containing a silver component. Examples of silver-based particles include silver alone, the above-described silver alloy, and core-shell particles having silver-based particles as a core.

In another preferred embodiment, the conductive powder includes metal-ceramic core-shell particles. The metal-ceramic core-shell particle has a core part including a metal material and a covering part covering at least a part of the surface of the core part and including the ceramic material. Ceramic materials are excellent in chemical stability, heat resistance, and durability. Therefore, the stability of the conductive powder in the photosensitive composition can be further improved by adopting the form of the metal-ceramic core-shell particles. In addition, the fine line formability can be further improved. In addition, in an application for manufacturing a ceramic electronic component, it is possible to improve the durability of the ceramic electronic component by increasing the integrity and adhesion between the ceramic substrate and the conductive layer.

In the metal-ceramic core-shell particles, examples of the metal material constituting the core portion include the above-mentioned simple metals, and mixtures and alloys thereof. Of these, silver-based particles are preferred for the reasons described above. In other words, the conductive powder preferably contains silver-ceramic core-shell particles.

The ceramic material constituting the covering portion is not particularly limited. For example, zirconium oxide (zirconia), magnesium oxide (magnesia), aluminum oxide (alumina), silicon oxide (silica), titanium oxide (titania). , Oxide materials such as cerium oxide (ceria), yttrium oxide (yttria) and barium titanate; complex oxide materials such as cordierite, mullite, forsterite, steatite, sialon, zircon and ferrite; silicon nitride Nitride materials such as (silicon nitride) and aluminum nitride (aluminum nitride); carbide materials such as silicon carbide (silicon carbide); hydroxide materials such as hydroxyapatite; and the like. For example, in an application in which a ceramic electronic component is manufactured by forming a conductive layer on a ceramic base material, the same type of ceramic material as the ceramic base material or excellent in affinity is preferable.

Although not particularly limited, the content ratio of the ceramic material in the metal-ceramic core-shell particles may be, for example, 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the metal material in the core part. . The metal-ceramic core-shell particles can be produced by a conventionally known method. For example, as described in paragraphs 0025 to 0028 of Japanese Patent No. 5075222, which is a prior application of the present applicant, an organic metal compound (for example, metal alkoxide or chelate compound) having a metal element and a target metal element Alternatively, it can be produced by reacting with an oxide sol.

Although not particularly limited, the D ₅₀ particle size of the conductive powder is preferably about 1.0 to 5.0 μm in view of the exposure performance in the exposure step. D ₅₀ particle size to within the above range, to improve the exposure performance of the exposure portion, it is possible to form a fine line even more stably. In this specification, “D ₅₀ particle size” refers to a particle size corresponding to an integrated value of 50% from the smaller particle size side in a volume-based particle size distribution based on the laser diffraction / scattering method.
From the viewpoint of improving the stability by suppressing aggregation in the photosensitive composition, the D ₅₀ particle size of the conductive powder is, for example, 1.5 μm or more, 2.0 μm or more, 2.5 μm or more. May be. In addition, from the viewpoint of improving the fine line formability and promoting the densification and low resistance of the conductive layer, the D ₅₀ particle size of the conductive powder is, for example, 4.5 μm or less, 4.0 μm or less. May be.

Although not particularly limited, the particle size distribution of the entire conductive powder is preferably multimodal. In other words, it is preferable to include the first conductive powder and the second conductive powder having different D ₅₀ particle sizes. As a result, compared to the case where the difference in D ₅₀ particle size between the first conductive powder and the second conductive powder is small, the density and filling properties of the conductive layer are improved and the electrical resistance is suitably reduced. be able to. The D ₅₀ particle size of the first conductive powder and the second conductive powder may be at least 0.5 μm, typically 0.5 to 3.0 μm, for example, about 1.0 to 2.0 μm apart. . In one specific example, the D ₅₀ particle size of the first conductive powder is approximately in the range of 3 to 5 μm, for example 3.5 to 4.5 μm, and the D ₅₀ particle size of the second conductive powder is approximately 1 to It may be in the range of 3.5 μm, for example 1.5-3 μm.

Although not particularly limited, the shape of the conductive particles constituting the conductive powder is typically substantially spherical with an average aspect ratio (major axis / minor axis ratio) of approximately 1 to 2, preferably 1 to A spherical shape of 1.5, for example 1 to 1.2. Thereby, exposure performance can be realized more stably. The conductive powder may have an average aspect ratio in the above range. In the present specification, the “average aspect ratio” refers to an arithmetic average value of aspect ratios calculated from observation images obtained by observing a plurality of conductive particles with an electron microscope. Further, in this specification, “spherical” indicates a form that can be generally regarded as a sphere (ball) as a whole, and is a term that may include an elliptical shape, a polygonal shape, a disk-shaped shape, and the like.

Although not particularly limited, the entire conductive powder may have a lightness L ^* of 50 or more in an L ^* a ^* b ^* color system based on Japanese Industrial Standard JIS Z 8781: 2013. As a result, in the exposure process, the irradiation light can stably reach the deep part of the exposed part, and for example, a thick conductive layer having a film thickness of 5 μm or more, further 10 μm or more can be stably realized. be able to. From this viewpoint, the lightness L ^* of the conductive powder may be approximately 55 or more, for example, 60 or more. Lightness L ^* can be adjusted for example by the type and D ₅₀ particle size of the conductive powder mentioned above. The lightness L ^* can be measured with a spectrocolorimeter in accordance with, for example, Japanese Industrial Standard JIS Z 8722: 2009.

In addition, the organic surface treating agent may adhere to the surface of the conductive powder. The organic surface treatment agent, for example, improves the dispersibility of the conductive powder in the photosensitive composition, increases the affinity with other components, and prevents the surface oxidation of the metal constituting the conductive powder. It can be used for at least one of these purposes. Examples of the organic surface treatment agent include fatty acids such as carboxylic acids, benzotriazole compounds, and the like.

Although not particularly limited, the proportion of the conductive powder in the entire photosensitive composition is preferably about 50% by mass or more, typically 60 to 95% by mass, for example 70 to 90% by mass. By satisfying the above range, a conductive layer excellent in denseness and electrical conductivity can be suitably formed. Moreover, the handleability of a photosensitive composition and the workability | operativity at the time of shape | molding an electrically conductive film can be improved.

<Photopolymerizable compound>
The photopolymerizable compound is a component that is polymerized and cured by active species generated by the decomposition of the photopolymerization initiator described later. The polymerization reaction may be addition polymerization or ring-opening polymerization. The photopolymerizable compound typically has one or more unsaturated bonds and / or cyclic structures. The photopolymerizable compound includes a monomer, a polymer, and an oligomer. Of these, monomers are preferred. It does not specifically limit as a photopolymerizable compound, For example, according to a use, the kind of base material, etc., 1 type (s) or 2 or more types can be selected suitably and used. As a suitable example of a photopolymerizable compound, a radical polymerizable monomer having one or more unsaturated bonds such as a (meth) acryloyl group or a vinyl group, or a cationic polymerizable monomer having a cyclic structure such as an epoxy group Is mentioned.

In a preferred embodiment, the photopolymerizable compound contains a (meth) acrylate monomer having a (meth) acryloyl group. By including the (meth) acrylate monomer, the flexibility of the conductive layer and the followability to the substrate can be improved. As a result, the occurrence of defects such as peeling and disconnection can be suppressed at a higher level. In the present specification, “(meth) acryloyl” includes “methacryloyl” and “acryloyl”, and “(meth) acrylate” is a term including “methacrylate” and “acrylate”. The (meth) acrylate monomer includes a monofunctional (meth) acrylate having one functional group per molecule, a polyfunctional (meth) acrylate having two or more functional groups per molecule, and a modified product thereof. Is included.

As a suitable example of (meth) acrylate monomer, triethylene glycol monoacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monoacrylate, tetraethylene glycol monomethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate And polyfunctional (meth) acrylates such as dipentaerythritol hexaacrylate, tripentaerythritol heptaacrylate, tripentaerythritol octaacrylate, tetrapentaerythritol nonaacrylate, and tetrapentaerythritol decaacrylate. Among these, from the viewpoint of improving photocurability, a monomer having 5 or more (meth) acryloyl groups per molecule is preferable.

In another preferred embodiment, the photopolymerizable compound includes a photopolymerizable compound (urethane bond-containing compound) having a urethane bond (—NH—C (═O) —O—). As a result, it is possible to improve the etching resistance of the exposed portion and realize a conductive layer excellent in flexibility and stretchability. Therefore, the adhesiveness between the base material and the conductive layer can be improved, and the occurrence of problems such as peeling and disconnection can be suppressed at a higher level. Preferred examples of the urethane bond-containing compound include urethane-modified (meth) acrylate and urethane-modified epoxy. The proportion of the urethane bond-containing compound in the entire photopolymerizable compound is, on a mass basis, approximately 30% by mass or more, typically 50% by mass or more, more preferably, for example, 95% by mass or more, substantially 100%. It may be mass%.

Although not particularly limited, the weight average molecular weight of the photopolymerizable compound is preferably about 100 to 10,000, typically 200 to 5,000, for example 300 to 2,000. In the present specification, “weight average molecular weight” refers to a weight-based average molecular weight measured by gel chromatography (Gel Permeation Chromatography: GPC) and converted using a standard polystyrene calibration curve. When a photopolymerizable compound is a monomer, it is synonymous with molecular weight.

Although not particularly limited, the proportion of the photopolymerizable compound in the entire photosensitive composition is generally 0.1 to 20% by mass, typically 0.5 to 10% by mass, for example 2 to 8% by mass. %, And more preferably 3 to 6% by mass. By satisfy | filling the said range, photocurability of the photosensitive composition is fully exhibited, and a conductive layer can be stably formed in a higher level.

<Photopolymerization initiator>
The photopolymerization initiator is a component that is decomposed by irradiation with light energy such as ultraviolet rays, generates active species such as radicals and cations, and initiates the polymerization reaction of the photopolymerizable compound. In the photosensitive composition disclosed herein, the photopolymerization initiator contains at least two components: (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; (2) α-aminoalkyl Includes phenones;

The photopolymerization initiators (1) and (2) typically have different absorption wavelengths. Therefore, by using these in combination, the absorption wavelength region is broadened compared with the case where one kind of photopolymerization initiator is used alone, and active species can be generated with high efficiency. Also, due to the synergistic effect of the photopolymerization initiators (1) and (2) above, in the development process, for example, the time to the break point (BP) is kept as before, and a long development margin time is secured. can do. Combined with the effects described above, the technique disclosed herein can improve the fine line formability and form fine lines with a line width of 30 μm or less with good reproducibility. Hereinafter, the photopolymerization initiators (1) and (2) will be described.

(1) 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide is monoacylphosphine oxide (MAPO). Commercially available products include DAROCUR (trademark) TPO, IRGACURE (trademark) TPO (both manufactured by BASF Japan Ltd.) and the like. Acylphosphine oxide photopolymerization initiators are excellent in compatibility with photopolymerizable compounds and organic dispersion media. Therefore, it is effective for improving the storage stability of the photosensitive composition.

Incidentally, as a photopolymerization initiator classified into the same acylphosphine oxide system as in the above (1), bisacylphosphine oxide (BAPO), for example, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Is mentioned. However, as shown in the test examples described later, when bisacylphosphine oxide is used instead of the above (1), the effects of the technique disclosed herein as described above are not exhibited. That is, it can be said that the combined use of the photopolymerization initiators (1) and (2) has specificity.

In the technology disclosed here, the above (1) is the main component of the photopolymerization initiator. In other words, when the total amount of the photopolymerization initiator is 100% by mass, the proportion of the above (1) accounts for 50% by mass or more. Thereby, the fine line formability can be improved and a fine line can be suitably formed. From this viewpoint, the ratio of (1) may be, for example, 75% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass or more. Further, from the viewpoint of better exhibiting the synergistic effect with (2) above and from the viewpoint of improving the adhesion between the base material and the conductive layer, the ratio of (1) is generally 90% by mass or less, preferably It may be 85% by mass or less.

(2) The α-aminoalkylphenone may be any compound having an α-aminoalkylphenone skeleton, and one or more of the conventionally known compounds can be appropriately selected and used. The α-aminoalkylphenone skeleton can be understood as, for example, a functional group having an intramolecular cleavage type photopolymerization initiating ability. The alkyl moiety may be linear or branched. The alkyl moiety may have a substituent. A preferred example of α-aminoalkylphenones is a compound having a molecular weight of about 1000 or less, typically 200 to 500, for example 250 to 400. Another preferred example is a compound having an α-aminoacetophenone skeleton. As a preferred example of the compound having an α-aminoacetophenone skeleton, a compound having the following structural part (A) can be mentioned.

In the above (A), R ¹ and R ² are each independently selected from a hydrocarbon group having 1 to 18 carbon atoms. R ¹ and R ² may be the same or different. R ¹ is, for example, an alkyl group having 1 to 18 carbon atoms. R ¹ preferably has 1 to 8 carbon atoms, typically 1 to 4, for example 1, 2 or 3. R ² is, for example, an alkyl group having 1 to 18 carbon atoms, an aryl group, or an arylalkyl group. R ² preferably has 1 to 8 carbon atoms. R ³ and R ⁴ are each independently selected from a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. R ³ and R ⁴ may be the same or different. R ³ and R ⁴ are each independently, for example, an alkyl group having 1 to 18 carbon atoms, an aryl group, an arylalkyl group, or a cyclic alkyl ether group in which R ³ and R ⁴ are bonded. The total number of carbon atoms of R ³ and R ⁴ is preferably 1-8, typically 1-6, for example 2-4.

Specific examples of the above (2) include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl]- 1- [4- (4-morpholinyl) phenyl] -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-monoforinopropan-1-one, N, N-dimethylaminoacetophenone Etc. Examples of commercially available products include IRGACURE (trademark) 369, IRGACURE (trademark) 379, IRGACURE (trademark) 907 (all manufactured by BASF Japan Ltd.), and the like.

Although not particularly limited, from the viewpoint of exhibiting the effect of the technology disclosed herein at a high level, when the total amount of the photopolymerization initiator is 100% by mass, the ratio of (2) above is: It may be approximately 10% by mass or more. Further, from the viewpoint of improving the adhesion between the base material and the conductive layer, the ratio of (2) may be 15% by mass or more. Further, from the viewpoint of improving the fine line formability better, the proportion of the above (2) may be, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less.

Although not particularly limited, from the viewpoint of exhibiting the effects of the technology disclosed herein at a high level, when the total amount of the photopolymerization initiator is 100% by mass, the above (1), (2) Is approximately 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and may be, for example, 100% by mass.

Although not particularly limited, the mass ratio of the above (1) and (2) is preferably about 50:50 to 95: 5. As a result, the fine line formability can be improved and the effects of the technology disclosed herein can be exhibited at a higher level. For example, even a conductive layer with a finer line can be formed with high accuracy. Further, from the viewpoint of improving the etching resistance of the exposed portion and suppressing the peeling of the conductive layer, the mass ratio of (1) and (2) is preferably 50:50 to 90:10, Preferably it is 50:50 to 85:15.

Although not particularly limited, the ratio of the photopolymerization initiator in the entire photosensitive composition is generally 0.01% by mass or more, typically 0.04% by mass or more, for example 0.05% by mass or more. It is good to be. By this, the photocurability of the photosensitive composition is fully exhibited and a conductive layer can be formed stably. The proportion of the photopolymerization initiator in the entire photosensitive composition is generally 0.5% by mass or less, typically 0.3% by mass or less, preferably 0.2% by mass or less, for example 0.1% by mass. % Or less. This makes it possible to balance the conflicting etching resistance and peelability at a higher level in the development process. Therefore, it is possible to secure a longer development margin time and improve the fine line formability better.

Although not particularly limited, the content ratio of the photopolymerization initiator is generally 0.01 to 1 part by mass, typically 0.02 to 0.2 part by mass with respect to 100 parts by mass of the conductive powder. For example, it may be 0.05 to 0.1 parts by mass. The content ratio of the photopolymerization initiator is generally 0.1 to 25 parts by mass, typically 0.2 to 5 parts by mass, for example 0.5 to 3 parts by mass, relative to 100 parts by mass of the photopolymerizable compound. Part or even 1 to 2 parts by mass.

<Organic binder>
The photosensitive composition may contain an organic binder in addition to the above essential components. An organic binder is a component which improves the adhesiveness of a base material and an uncured electrically conductive film. As the organic binder, one or two or more kinds of organic binders can be appropriately selected and used according to, for example, the type of the base material, the photopolymerizable compound, the type of the photopolymerization initiator, and the like. The organic binder is preferably one that can be easily removed with an etching solution in the development step. For example, when an alkaline etching solution is used in the development process, a hydroxyl group (—OH), a carboxyl group (—C (═O) OH), an ester bond (—C (═O) O—), a sulfo group A compound having a structural portion exhibiting acidity, such as (—SO ₃ H), is preferred. This makes it difficult for residues to remain in unexposed portions, and for example, a space between fine lines can be stably secured.

Examples of suitable organic binders include cellulose polymers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and hydroxymethyl cellulose, acrylic resins, phenol resins, alkyd resins, polyvinyl alcohol, polyvinyl butyral, and the like. Of these, hydrophilic organic binders such as cellulosic polymers and acrylic resins are preferred from the viewpoint of easy removal in the development step.

When the photosensitive composition contains an organic binder, it is not particularly limited, but the ratio of the organic binder to the entire photosensitive composition is generally 0.1 to 20% by mass, typically 0.5 to It may be 10% by weight, for example 1-5% by weight. Although not particularly limited, the content ratio of the photopolymerizable compound and the organic binder is substantially the same (the difference in the content ratio between the two is approximately 1% by mass or less, for example, 0.5% by mass or less). Good. This makes it possible to balance the opposite etching resistance (adhesiveness) and peelability at a higher level in the development process.

<Organic dispersion medium>
The photosensitive composition may contain an organic dispersion medium in which these are dispersed in addition to the essential components described above. The organic dispersion medium is a component that imparts appropriate viscosity and fluidity to the photosensitive composition to improve the handleability of the photosensitive composition and improve workability when forming a conductive film. is there. As the organic dispersion medium, one or two or more kinds of organic dispersion media can be appropriately selected and used according to, for example, the type of the photopolymerizable compound and the photopolymerization initiator.

Preferred examples of the organic dispersion medium include alcohol solvents such as terpineol, dihydroterpineol (mentanol), texanol, 3-methyl-3-methoxybutanol, and benzyl alcohol; glycol solvents such as ethylene glycol, propylene glycol, and diethylene glycol; Ether solvents such as dipropylene glycol methyl ether, methyl cellosolve (ethylene glycol monomethyl ether), cellosolve (ethylene glycol monoethyl ether), butyl carbitol (diethylene glycol monobutyl ether); diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, Butyl glycol acetate, butyl diglycol acetate, butyl cellosolve acetate Ester solvents such as carbonate, butyl carbitol acetate (diethylene glycol monobutyl ether acetate) and isobornyl acetate; hydrocarbon solvents such as toluene, xylene, naphtha and petroleum hydrocarbons; organic solvents such as mineral spirits; Can be mentioned.

Among these, from the viewpoint of improving the storage stability of the photosensitive composition and the handleability during formation of the conductive film, an organic solvent having a boiling point of 150 ° C. or higher, more preferably an organic solvent having a boiling point of 170 ° C. or higher is preferable. As another preferred example, an organic solvent having a boiling point of 250 ° C. or lower, and further an organic solvent having a boiling point of 220 ° C. or lower is preferable from the viewpoint of keeping the drying temperature after printing the conductive film low. As a result, productivity can be improved and production cost can be reduced.

Also, for example, in an application where a conductive layer is formed on a ceramic substrate to produce a ceramic electronic component, an organic solvent having low permeability to the ceramic green sheet is preferable. Examples of the organic solvent having low permeability to the ceramic green sheet include an organic solvent having a three-dimensionally bulky structure such as a cyclohexyl group and a tert-butyl group, and an organic solvent having a relatively large molecular weight. Furthermore, for example, an organic solvent that can suitably dissolve an organic solvent having low permeability to the ceramic green sheet as described above and components (for example, a photopolymerizable substance and / or a photopolymerization initiator) contained in the photosensitive composition. It is also preferable to mix a solvent with an arbitrary ratio and use it as an organic dispersion medium.

Commercially available organic solvents having the above properties (boiling point and permeability to ceramic green sheets) include, for example, Dawanol DPM (trademark) (boiling point: 190 ° C., manufactured by Dow Chemical Company), Dawanol DPMA (trademark) ) (Boiling point: 209 ° C., manufactured by Dow Chemical Company), mentanol (boiling point: 207 ° C.), mentanol P (boiling point: 216 ° C.), isoper H (boiling point: 176 ° C., manufactured by Kanto Fuel Co., Ltd.), SW-1800 (Boiling point: 198 ° C., manufactured by Maruzen Petroleum Co., Ltd.).

When the photosensitive composition contains an organic dispersion medium, it is not particularly limited, but the ratio of the organic dispersion medium to the entire photosensitive composition is generally 1 to 50% by mass, typically 3 to It may be 30% by weight, for example 5 to 20% by weight.

<Other ingredients>
In addition to the above-described components, the photosensitive composition may further contain various additive components as long as the effects of the technology disclosed herein are not significantly impaired. As the additive component, one or more kinds can be appropriately selected from conventionally known ones. Examples of additive components include, for example, inorganic fillers, photosensitizers, polymerization inhibitors, radical scavengers, antioxidants, ultraviolet absorbers, plasticizers, surfactants, leveling agents, thickeners, dispersants, Antifoaming agents, anti-gelling agents, stabilizers, preservatives, pigments and the like can be mentioned. Although not particularly limited, the ratio of the additive component in the entire photosensitive composition is preferably 5% by mass or less, for example, 3% by mass or less.

As described above, the photosensitive composition disclosed herein contains both of the above two components (1) and (2) as a photopolymerization initiator. And when the whole photoinitiator is 100 mass%, the ratio of said (1) occupies 50 mass% or more. This makes it possible to balance etching resistance (adhesion) and peelability at a higher level in the development process. That is, the etching resistance of the exposed portion can be improved, and a long development margin time can be secured. As a result, the exposed portion can be appropriately retained on the substrate after the development step, and occurrence of problems such as peeling and disconnection can be suppressed. In addition, the peelability of the conductive film can be improved, the unexposed portion can be appropriately removed, and the exposed portion can be prevented from becoming too thick. In other words, the fine line formability of the exposed portion can be improved. As a result, a space can be secured stably between adjacent wirings, and occurrence of short circuit defects can be suppressed. In addition, according to the technology disclosed herein, these effects can be combined to form fine lines with a line width of 30 μm or less with good reproducibility. In addition, the yield can be improved.

<Use of photosensitive composition>
According to the photosensitive composition disclosed herein, fine lines with a line width finer than 30 μm can be stably formed with high resolution. Further, it is possible to reduce peeling of the conductive layer, disconnection, and the like, and to suppress occurrence of a short circuit defect. Therefore, the photosensitive composition disclosed herein can be suitably used for forming a conductive layer in various electronic components such as inductance components, capacitor components, and multilayer circuit boards.

The electronic component may be of various mounting forms such as a surface mounting type or a through hole mounting type. The electronic component may be a laminated type, a wound type, or a thin film type. Typical examples of the inductance component include a high frequency filter, a common mode filter, a high frequency circuit inductor (coil), a general circuit inductor (coil), a high frequency filter, a choke coil, and a transformer.

Further, the photosensitive composition in which the conductive powder contains metal-ceramic core-shell particles can be suitably used for forming a conductive layer of a ceramic electronic component. In the present specification, the “ceramic electronic component” includes all electronic components having an amorphous ceramic substrate (glass ceramic substrate) or a crystalline (ie non-glass) ceramic substrate. Typical examples include high-frequency filters with ceramic substrates, ceramic inductors (coils), ceramic capacitors, low-temperature fired multilayer ceramic substrates (Low Temperature Co-fired Ceramics Substrate), high-temperature fired multilayer ceramic substrates (High Temperature) Co-fired Ceramics Substrate: HTCC base material).

FIG. 1 is a cross-sectional view schematically showing the structure of the multilayer chip inductor 1. Note that the dimensional relationship (length, width, thickness, etc.) in FIG. 1 does not necessarily reflect the actual dimensional relationship. Moreover, the code | symbol X, Y in drawing represents the left-right direction and the up-down direction, respectively. However, this is only a direction for convenience of explanation.

The multilayer chip inductor 1 includes a main body 10 and external electrodes 20 provided on both side portions of the main body 10 in the left-right direction X. The multilayer chip inductor 1 has a size such as a 1608 shape (1.6 mm × 0.8 mm) and a 2520 shape (2.5 mm × 2.0 mm), for example.

The main body 10 has a structure in which a ceramic layer (dielectric layer) 12 and an internal electrode layer 14 are integrated. The ceramic layer 12 is made of, for example, a ceramic material as described above that can form a coating portion of conductive powder. An internal electrode layer 14 is disposed between the ceramic layers 12 in the vertical direction Y. The internal electrode layer 14 is formed using the above-described photosensitive composition. Internal electrode layers 14 adjacent in the vertical direction Y across the ceramic layer 12 are electrically connected through vias 16 provided in the ceramic layer 12. Thus, the internal electrode layer 14 is configured in a three-dimensional spiral shape (spiral shape). Both ends of the internal electrode layer 14 are connected to the external electrode 20.

Such a multilayer chip inductor 1 can be manufactured, for example, by the following procedure.
That is, first, a paste containing a ceramic material as a raw material, a binder resin, and an organic solvent is prepared and supplied onto a carrier sheet to form a ceramic green sheet. Next, this ceramic green sheet is rolled and then cut to a desired size to obtain a plurality of ceramic layer forming green sheets. Next, via holes are appropriately formed at predetermined positions of the plurality of ceramic layer forming green sheets using a punching machine or the like.

Next, using the above-described photosensitive composition, a conductive film having a predetermined coil pattern is formed at predetermined positions on the plurality of ceramic layer forming green sheets. As an example, the following process: (Step S1: Forming process of film-like body) A conductive film made of a dry body of the photosensitive composition by applying the photosensitive composition onto a green sheet for forming a ceramic layer and drying it. (Step S2: exposure step) a step of covering the conductive film with a photomask having a predetermined opening pattern, exposing through the photomask, and partially photocuring the conductive film; (step S3: development) Step) The conductive film in an unbaked state can be formed by a manufacturing method including a step of etching the conductive film after photocuring to remove an unexposed portion.

In forming the conductive film using the photosensitive composition, a conventionally known method can be appropriately used. For example, in (Step S1), the photosensitive composition can be applied using various printing methods such as screen printing, a bar coater, or the like. The photosensitive composition may be dried at a temperature below the boiling point of the photopolymerizable compound and the photopolymerization initiator, typically 50 to 100 ° C. In (Step S2), for the exposure, for example, an exposure apparatus that emits light in a wavelength range of 10 to 500 nm, for example, an ultraviolet irradiation lamp such as a high-pressure mercury lamp, a metal halide lamp, or a xenon lamp can be used. In (Step S3), an alkaline etching solution can be typically used for etching. For example, an aqueous solution containing sodium hydroxide or sodium carbonate can be used. The concentration of the alkaline aqueous solution is preferably adjusted to 0.01 to 0.5% by mass, for example.

Next, (Step S4: Firing step) A plurality of ceramic layer forming green sheets on which an unfired conductive film is formed are laminated and pressure-bonded. This produces a laminate of unfired ceramic green sheets. Next, the laminate of ceramic green sheets is fired at 600 to 1000 ° C., for example. As a result, the ceramic green sheet is integrally sintered, and the main body 10 including the ceramic layer 12 and the internal electrode layer 14 made of a fired body of the photosensitive composition is formed. The external electrode 20 is formed by applying an appropriate external electrode forming paste to both ends of the main body 10 and baking the paste.
The multilayer chip inductor 1 can be manufactured as described above.

Hereinafter, some examples relating to the present invention will be described, but the present invention is not intended to be limited to those shown in the examples.

(Preparation of silver powder)
First, two types of commercially available silver powders (silver powders a and b) having different D ₅₀ particle sizes were prepared. The silver powder a has a D ₅₀ particle size of 3.9 μm, and the silver powder b has a D ₅₀ particle size of 2.8 μm. The silver powders a and b both have a lightness L ^* of 50 to 80 in the L ^* a ^* b ^* color system based on the Japanese Industrial Standard JIS Z 8781: 2013.

Moreover, the silver powder c was prepared using the silver powder a. Specifically, first, zirconium butoxide was added to methanol to prepare a coating solution. Next, silver powder a was added to this coating solution and stirred for 1 hour. Next, solid content was collect | recovered from the coating liquid, and it dried at 100 degreeC. As a result, silver powder (silver-zirconia core-shell particles) whose surface was coated with zirconium butoxide in an amount of 0.5 parts by mass in terms of zirconium oxide (ZrO ₂ ) was obtained with respect to 100 parts by mass of silver powder. In this way, silver powder c was prepared.

(Preparation of photopolymerization initiator)
Next, four types of commercially available photopolymerization initiators (initiators a to d) shown below were prepared. The initiators a and b are α-aminoalkylphenone photopolymerization initiators, and the initiators c and d are acylphosphine oxide photopolymerization initiators.
Initiator a: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1
Initiator b: 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone Initiator c: 2,4,6 -Trimethylbenzoyl-diphenyl-phosphine oxide initiator d: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide

(Preparation of photosensitive composition)
First, a urethane acrylate monomer as a photopolymerizable compound, an organic binder, and the photopolymerization initiator are weighed so as to have the content shown in Table 1, and dissolved in an organic dispersion medium to prepare a vehicle. did. A photosensitive composition (Examples 1 to 7 and Comparative Examples 1 to 6) was prepared by mixing the prepared silver powder and the prepared vehicle at a mass ratio of 77:23. In addition, mass ratio shown in Table 1 is a thing when the whole photosensitive composition is 100 mass%, and when the sum total of mass ratio shown in Table 1 is less than 100 mass%, it is other additive components. (For example, a polymerization inhibitor, a sensitizer, a gelation inhibitor, and an ultraviolet absorber) are included in a trace amount.

(Production of wiring pattern)
First, the prepared photosensitive composition was applied onto a commercially available ceramic green sheet using a stainless steel screen. Next, this was dried at 60 ° C. for 15 minutes to form a conductive film on the green sheet (forming process of the film-like body). Next, a photomask was put on the conductive film. At this time, a photomask having a spiral pattern in which the line width of the wiring is 25 μm and the interval (space) between adjacent lines is 25 μm (L / S = 25 μm / 25 μm) is used. With this photomask covered, light was irradiated with an intensity of 2500 mJ / cm ² by an exposure machine to cure the exposed portion (exposure process). After the exposure, 0.1% by mass of an alkaline Na ₂ CO ₃ aqueous solution was sprayed onto the surface of the ceramic green green sheet until the break point (BP) was reached (development process). Here, B.I. P. The time until the unexposed portion was developed with 0.1% by weight of an alkaline etching solution and it was confirmed by visual observation that the unexposed portion disappeared was used. Thus, after removing an unexposed part, it wash | cleaned with the pure water and was made to dry at room temperature. And this was baked at 700 degreeC (baking process). Thus, a conductive layer having a wiring pattern in which spiral wirings were arranged was formed on the ceramic green sheet.

(Evaluation of wiring pattern)
About the produced wiring pattern, peeling, line width, and development margin were evaluated, and comprehensive evaluation was performed based on these evaluations.

・ Evaluation of peeling:
The wiring pattern was observed with an electron microscope, and peeling was evaluated. The observation image was taken at a magnification of 200 times. And the presence or absence of peeling and a disconnection was confirmed with the obtained observation image. The results are shown in the column “Evaluation of peeling” in Table 1. The notation of the column is as follows.
“○”: No peeling “△”: Partial peeling (no disconnection)
“×”: peeling or disconnection

・ Evaluation of line width:
The line width of the wiring pattern was measured from the observed image. The line width was measured for a plurality of visual fields, and the arithmetic average value was defined as the line width (μm). The results are shown in the “Line width” column of Table 1. Moreover, the notation of the column of evaluation is as follows.
“◯”: 20 to 30 μm (within target value range)
“×”: 30 μm or more FIG. 2 shows the relationship between the content ratio of the initiator c and the line width of the wiring pattern for the evaluation results of Comparative Examples 1 to 3 and Examples 1 to 4.

・ Evaluation of development margin:
In the above exposure process, an alkaline etching solution was sprayed for 10 seconds (BP + 10 seconds) beyond the break point. Then, the conductive film after the exposure process was observed with an electron microscope in the same manner as described above, and the development margin was evaluated from the obtained observation image. The results are shown in the column “Evaluation of development margin” in Table 1. The notation of the column is as follows.
“O”: The shape of the conductive film is maintained “X”: The shape of the conductive film is not maintained

·Comprehensive evaluation:
“◯”: In the above evaluations of peeling, line width, and development margin, there is no Δ or × (all are ◯)
“△”: In each evaluation of the above-described peeling, line width, and development margin, “Δ” is 1, and the remaining is “X”: In each evaluation of the above-described peeling, line width, and development margin, “x” is 1 There are more than two

Comparative Examples 1 and 2 are test examples using only initiator a. As shown in Table 1, in Comparative Example 1, although a development margin could be secured for 10 seconds or more, the conductive pattern had a large variation in line width, and thickening of the line width was confirmed in some places. As a result, the line width was too large than the target value, and it was difficult to form a stable fine line. Further, in Comparative Example 2 in which the content ratio of the initiator a was reduced as compared with Comparative Example 1, a sufficient development margin could not be secured. Comparative Example 4 is a test example using only initiator c. As shown in Table 1, in Comparative Example 4, peeling and disconnection were confirmed in the conductive pattern, and it was difficult to form a fine line.

Comparative Example 3 and Examples 1 to 4 are test examples in which initiators a and c are used in combination. As shown in Table 1 and FIG. 2, in Comparative Example 3 in which the content ratio of the initiator c is small, the effect of addition of the initiator c is not sufficiently exhibited, and as in Comparative Example 1, formation of a stable fine line Was difficult. On the other hand, in Examples 1 to 4 in which the content ratio of the initiator c is 50% by mass or more of the entire photopolymerization initiator, a sufficient development margin is ensured and a fine line having a desired line width is stable. Was formed. Moreover, the fine wire formability was further improved by increasing the content ratio of the initiator c. In particular, in Examples 1 to 3 in which the mass ratio of initiator c: initiator a was 50:50 to 85:15, the etching resistance of the exposed portion was improved, and peeling of the conductive layer was better suppressed. .

Example 5 is a test example in which an initiator b which is the same α-aminoalkylphenone is used in place of the initiator a. As shown in Table 1, also in Example 5, as in Examples 1 to 4, a sufficient development margin was ensured and formation of a stable fine line was realized. In other words, even when the initiator b is used in place of the initiator a, the effect of the technique disclosed herein was exhibited.

Comparative Examples 5 and 6 are test examples using the same acylphosphine oxide-based initiator d instead of the initiator c. As shown in Table 1, in Comparative Examples 5 and 6, unlike Examples 1 to 4, the development margin was insufficient and / or formation of a stable fine line was difficult. In other words, when the initiator d was used instead of the initiator c, the effect of the technique disclosed here was not exhibited.

Examples 6 and 7 are test examples using silver powder c instead of silver powder a and b. As shown in Table 1, in Examples 6 and 7, as in Examples 1 to 4, a sufficient development margin was ensured, and formation of a stable fine line was realized. Furthermore, compared with the case where silver powder a and b are used, the effect of the technique disclosed here was exhibited at a higher level, and the fine line formability was further improved.

As described above, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (initiator c) and α-aminoalkylphenones (initiators a and b) are used in combination as a photopolymerization initiator, In addition, by including 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide in a proportion of 50% by mass or more of the entire photopolymerization initiator, it is possible to ensure a long development margin time in the development process. It was. Moreover, the fine line formability of the exposed part could be improved. Thereby, even a fine line having a line width of 30 μm or less could be formed with good reproducibility. In addition, it was possible to improve the yield by suppressing the occurrence of defects such as short circuit failure, peeling, and disconnection. These results show the significance of the technology disclosed herein.

Although the present invention has been described in detail above, these are merely examples, and the present invention can be variously modified without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 Multilayer chip inductor 10 Main-body part 12 Ceramic layer 14 Internal electrode layer 20 External electrode

Claims (12)

A photosensitive composition used for producing a conductive layer including a wiring having a line width of 30 μm or less,
A conductive powder, a photopolymerizable compound, and a photopolymerization initiator,
The photopolymerization initiator is
At least two types of ingredients:
(1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide;
(2) α-aminoalkylphenones;
(1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide accounts for 50% by mass or more when the total amount of the photopolymerization initiator is 100% by mass object. The mass ratio of (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide to (2) α-aminoacetophenones is 50:50 to 90:10.
The photosensitive composition according to claim 1. The mass ratio of (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide to (2) α-aminoacetophenones is 50:50 to 85:15.
The photosensitive composition of Claim 1 or 2. When the total amount of the photosensitive composition is 100% by mass, the ratio of the photopolymerization initiator is 2% by mass or less.
The photosensitive composition according to any one of claims 1 to 3. The photopolymerizable compound includes a photopolymerizable compound having a urethane bond,
The photosensitive composition according to any one of claims 1 to 4. The conductive powder includes silver-based particles.
The photosensitive composition according to any one of claims 1 to 5. The conductive powder includes core-shell particles having a core portion including a metal material, and a covering portion that covers at least a part of the surface of the core portion and includes a ceramic material.
The photosensitive composition according to any one of claims 1 to 6. In the L ^* a ^* b ^* color system based on Japanese Industrial Standard JIS Z 8781: 2013, the lightness L ^* of the conductive powder is 50 or more.
The photosensitive composition according to any one of claims 1 to 7. An organic solvent having a boiling point of 150 ° C. or higher and 250 ° C. or lower;
The photosensitive composition according to any one of claims 1 to 8. With green sheets,
A conductive film disposed on the green sheet and made of a dried product of the photosensitive composition according to any one of claims 1 to 9,
A composite comprising. An electronic component comprising a conductive layer made of a fired body of the photosensitive composition according to any one of claims 1 to 9. A photosensitive composition according to any one of claims 1 to 9 is applied on a substrate, exposed to light, developed, and baked to form a conductive layer made of a baked product of the photosensitive composition. The manufacturing method of an electronic component including the process to do.

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