JP2020188154A - Method for manufacturing resin composition, resin-coated substrate and element chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the productivity of an element chip manufactured by a laser scribe step and a plasma dicing step.
SOLUTION: A preparatory step of preparing a substrate having a first surface and a second surface opposite to the first surface, and protection for forming a protective film covering the first surface of the substrate. A film forming step, an opening forming step of removing a part of the protective film by irradiating a laser beam to form an opening for exposing a part of the substrate, and a plasma of the substrate exposed from the opening. A protective film removing step of removing the protective film from the substrate after the individualizing step is provided. The protective film is made of a resin. The element chip contains the filler and the filler, and the average particle size of the filler is 10 nm or more and 1 μm or less, the filler has a near-infrared absorbing performance, and the laser beam includes a wavelength in the near-infrared region. Manufacturing method.
[Selection diagram] Fig. 3

Description

The present invention relates to a method for producing a resin composition, a resin-coated substrate, and an element chip.

As a method for dicing a substrate, plasma dicing in which the substrate is subjected to plasma etching and divided into individual chips has attracted attention. In plasma dicing, the element region of the substrate is usually protected by a protective film, and only the divided region defining the element region is etched by plasma. After plasma etching, the protective film is removed.

Patent Document 1 teaches that a protective film is formed using a water-soluble resin. As a result, the mask can be removed by washing with water.

Japanese Unexamined Patent Publication No. 2016-207737

When the protective film in the divided region is removed by laser light irradiation (laser scribing), a laser light having a wavelength in the ultraviolet region (wavelength 200 to 400 nm) is generally used. This is because the protective film containing the resin can absorb wavelengths in the ultraviolet region. However, this method using a laser beam in the ultraviolet region tends to reduce productivity and increase the cost.

One aspect of the present invention is a preparatory step of preparing a substrate having a first surface and a second surface opposite to the first surface, and a protective film covering the first surface of the substrate. A protective film forming step of forming, an opening forming step of removing a part of the protective film by irradiating a laser beam to form an opening for exposing a part of the substrate, and the above-mentioned exposed from the opening. The protective film includes a step of individualizing the substrate by etching the substrate with a laser and a step of removing the protective film from the substrate after the individualization step. Contains a resin and a filler, the average particle size of the filler is 10 nm or more and 1 μm or less, the filler has a near-infrared absorbing performance, and the laser beam includes a wavelength in the near-infrared region. , The method of manufacturing an element chip.

Another aspect of the present invention includes a substrate containing a semiconductor and a protective film covering the substrate, the protective film containing a resin and a filler, and the average particle size of the filler is 10 nm or more and 1 μm or less. Yes, the filler relates to a resin-coated substrate having near-infrared absorption performance.

Yet another aspect of the present invention is a resin composition for forming a protective film for coating a substrate containing a semiconductor, which contains a resin and a filler, and the average particle size of the filler is 10 nm or more and 1 μm or less. Yes, the filler relates to a resin composition having near-infrared absorbing performance.

According to the present invention, a desired device chip can be obtained with high productivity.

It is sectional drawing which shows typically the substrate which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the resin coated substrate which concerns on one Embodiment of this invention. It is a flowchart which shows the manufacturing method which concerns on one Embodiment of this invention. It is a top view which shows typically the transport carrier and the substrate held by this carrier. It is sectional drawing in line AA of FIG. 4A. It is sectional drawing which shows typically the substrate prepared by the preparation process which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the substrate after the protective film forming process which concerns on embodiment of this invention. It is sectional drawing which shows typically the substrate after the opening formation process which concerns on embodiment of this invention. It is sectional drawing which shows schematic | structure of the plasma processing apparatus. It is a block diagram of the plasma processing apparatus used in one Embodiment of this invention. It is sectional drawing which shows typically the substrate after the substrate etching process which concerns on embodiment of this invention. It is sectional drawing which shows typically the substrate (element chip) after the resin etching process which concerns on embodiment of this invention. It is sectional drawing which shows typically the element chip after the protective film removal process which concerns on embodiment of this invention.

The laser light in the ultraviolet region is usually obtained by converting the wavelength of the laser light having a wavelength in the near infrared region oscillated by using a YAG laser (Nd: YAG laser), a fiber laser, or the like by a wavelength conversion element. can get. However, it is difficult to efficiently convert a wavelength in the near-infrared region to a wavelength in the ultraviolet region, and in addition, replacement of a consumable wavelength conversion element is costly.

In this embodiment, a protective film is formed by a resin composition containing a filler having an average particle size of 10 nm or more and 1 μm or less and having near-infrared absorbing performance (hereinafter referred to as NIR-absorbing filler) together with a resin. To do. As a result, laser light having a wavelength in the near infrared region (specifically, 1064 nm, 1030 nm) can be used for laser scribing. Therefore, wavelength conversion to the ultraviolet region is omitted, productivity is improved, and cost reduction can be expected.

Further, the NIR-absorbing filler having such a small particle size has a remarkably high dispersion performance in the resin. Therefore, even when the protective film contains a high proportion of the NIR-absorbing filler, by cleaning with a solvent that dissolves the resin, the NIR-absorbing filler is easily washed away together with the dissolved resin and is transferred to the substrate. Remaining is suppressed. The present embodiment includes the above resin composition, a substrate on which a protective film formed by the resin composition is formed, and a method of manufacturing an element chip from the substrate.

[Resin composition]
The resin composition according to the present embodiment contains a resin and an NIR-absorbing filler.

(resin)
The resin is not particularly limited, but a water-soluble resin is preferable because it can be easily removed with water or a cleaning liquid containing water. Among the water-soluble resins, polystyrene sulfonic acid, water-soluble polyester, polyacrylic acid, polymethacrylic acid, polyacrylamide, and 2-acrylamide-2-methylpropanesulfonic acid are selected because they have low viscosity and high heat resistance. Preferable examples include a polymer or copolymer using a monomer, an oxazole-based polymer (for example, a polymer or a copolymer using 2-ethyl-4,5-dihydroxy-oxazole as a monomer) and the like. These may be used alone or in combination of two or more.

(NIR absorbent filler)
The NIR absorbent filler has a performance of absorbing near infrared rays (wavelengths of 750 nm or more and 3000 nm or less), particularly 800 nm or more and 1300 nm or less. As a result, laser light having a wavelength in the near infrared region can be used for laser scribing.

The NIR-absorbing filler may be an organic filler or an inorganic filler. Of these, an inorganic filler is preferable because it has excellent absorption of near infrared rays. Examples of the inorganic NIR-absorbing filler include metal oxides (aluminum oxide, titanium oxide, calcium oxide, magnesium oxide, etc.), metal carbonates (calcium carbonate, magnesium carbonate, etc.), and metal hydroxides (aluminum hydroxide). , Magnesium hydroxide, etc.), metal silicates (calcium silicate, magnesium silicate, etc.), aluminum nitride, silicon oxide, silicon carbide, talc, carbon materials (graphite, carbon black, carbon nanotubes, carbon nanofibers), etc. Can be mentioned. These may be used alone or in combination of two or more. Among them, at least one selected from the group consisting of carbon materials, metal carbonates, metal hydroxides and metal silicates is preferable because the absorption rate of laser light having a wavelength in the near infrared region is particularly high. Carbon materials are particularly preferred. The carbon material is particularly excellent in the ability to absorb wavelengths of 800 nm or more and 1300 nm or less.

The average particle size of the NIR-absorbing filler is 10 nm or more and 1 μm or less. When the average particle size is in this range, it becomes less susceptible to the influence of gravity and the NIR-absorbing filler is suppressed from precipitating in the resin composition. Therefore, it is excellent in dispersibility in the protective film. The average particle size may be 50 nm or more and 800 nm or less.

The average particle size is the particle size (D50; the same applies hereinafter) at a cumulative volume of 50% in the volume-based particle size distribution. The average particle size may be determined from the cross section in the thickness direction of the layer (protective film) containing the resin composition after drying. For example, an image obtained by taking a cross section of the layer in the thickness direction using a scanning electron microscope (SEM) or a transmission electron microscope (TEM) at a magnification of 100 times or more is divided into a resin and an NIR-absorbing filler and binary. To become. Then, it can be obtained by selecting an arbitrary plurality (for example, 10) of NIR-absorbing fillers from the observation field of view, calculating the particle size, and averaging them. The diameter of a circle having the same area as the cross-sectional area of the NIR-absorbing filler may be the particle diameter of the NIR-absorbing filler.

The mass ratio of the NIR-absorbing filler to the non-volatile components of the resin composition is not particularly limited. The mass ratio of the NIR-absorbing filler may be 0.1% or more and 40% or less, 0.1% or more and 10% or less, and 0.1% or more and 5% or less. Good. When the mass ratio of the NIR-absorbing filler is in this range, the laser light is more easily absorbed, while the excessive absorption of the laser light is suppressed, and the quality of laser processing is stabilized.

As will be described later, when ultrashort pulse laser light is used for laser scribing, the mass ratio of the NIR absorbing filler may be about 1/10 of the above. Specifically, when ultrashort pulse laser light is used, the mass ratio of the NIR absorbing filler may be 0.1% or more and 1% or less, and 0.1% or more and 0.5% or less. Good.

The mass ratio of the NIR-absorbing filler is the ratio of the mass of the NIR-absorbing filler to the total mass of the non-volatile components (for example, the resin, the NIR-absorbing filler, and other components excluding the solvent described later) in the resin composition. Yes, it is synonymous with the mass ratio of the NIR-absorbing filler in the protective film.

The NIR-absorbing filler may be hydrophilized. This is because when the resin is a water-soluble resin, the dispersibility of the NIR-absorbing filler in the water-soluble resin is likely to be further enhanced.

The hydrophilization treatment is not particularly limited, and for example, a method of introducing a hydrophilic group (hydroxy group, carboxy group, sulfonic acid group, carbonyl group, sulfofluoride group, etc.) on the surface of the NIR absorbing filler may be used. It may be a method of treating the NIR-absorbing filler with a surfactant, or a method of adsorbing a hydrophilic polymer on the NIR-absorbing filler. For the hydrophilic treatment of the carbon material, for example, a method of introducing a hydrophilic group into the surface is used.

The method for introducing the hydrophilic group is not particularly limited, and examples thereof include plasma treatment, corona discharge, sulfonate treatment, and fluorine gas treatment. The surfactant is not particularly limited, and may be an anionic surfactant (for example, an alkali metal salt of a higher fatty acid, an alkyl sulfonate, a sulfosuccinate ester salt, etc.), and a nonionic surfactant (for example, polyoxy). It may be an ethylene alkyl ether, a polyoxyethylene alkyl phenol ether, etc.), a cationic surfactant (for example, an aliphatic amine salt, an aliphatic quaternary ammonium salt, etc.), and an amphoteric surfactant (for example, an amphoteric surfactant). Aminocarboxylate, carboxybetaine type, sulfobetaine type, etc.) may be used. The hydrophilic polymer is not particularly limited, and may be carboxymethyl cellulose, polyvinyl alcohol, or the like, in addition to the resins listed as water-soluble resins.

The resin composition may contain a solvent. The solvent is not particularly limited as long as the resin can be dissolved, and is selected depending on the resin. When the resin is water-soluble, examples of the solvent include water and water-soluble organic solvents (methanol, ethanol, acetone, ethylmethyl ketone, acetonitrile, dimethylacetamide, etc.). These may be used alone or in combination of two or more.

[Resin coated substrate]
The resin-coated substrate according to the present embodiment includes a substrate containing a semiconductor and a protective film covering the substrate.

(Protective film)
The protective film contains a resin and a NIR-absorbing filler. The average particle size of the NIR-absorbing filler is 10 nm or more and 1 μm or less. The protective film is provided to protect the element region of the substrate from plasma.

The protective film can be obtained by molding the resin composition into a sheet, for example, and then attaching the sheet to the first surface, or by applying the resin composition to the first surface by a method such as spin coating or spray coating. It is formed by applying it to the first surface. A solvent may be added to the resin composition in order to adjust the viscosity.

The thickness of the protective film is not particularly limited. It is preferable that the protective film is not completely removed in the individualization step. The thickness of the protective film is set so as to be equal to or greater than this etching amount, for example, by calculating the amount (thickness) of etching of the protective film in the individualization step.

When a resin layer such as a die attach film (DAF) described later is arranged on the other surface (second surface) of the substrate, it is necessary to plasma etch this resin layer in addition to the substrate in the individualization step. There is. The ratio of the etching rate (protective film / semiconductor layer) between the protective film and the semiconductor layer by the plasma (first plasma P1) generated under the condition of etching the semiconductor is usually about 1/100. On the other hand, the etching rate of the protective film by the plasma (second plasma P2) generated under the condition of etching the resin is about the same as the etching rate of the resin layer. That is, while the resin layer is etched, the same amount of protective film is also etched. Therefore, the thickness of the protective film needs to be set in consideration of the ratio of the etching rate between the protective film and the object to be etched. Further, when the wiring layer to be described later is plasma-etched, the ratio of the etching rate between the protective film and the wiring layer by the plasma (third plasma P3) generated under the condition of etching the wiring layer (protective film / wiring layer). ) Must also be considered.

Select the ratio of the etching rate of the protective film by the first plasma P1 to the semiconductor layer (protective film / semiconductor layer) A, the ratio of the etching rate of the protective film by the second plasma P2 to the resin layer (protective film / When the selection ratio B is the resin layer) and the selection ratio C is the ratio of the etching rates between the protective film and the wiring layer generated by the third plasma P3 generated under the condition of etching the wiring layer (protection film / wiring layer). The thickness T of the protective film is
T = (semiconductor layer thickness x α / selectivity A) + (resin layer thickness x β / selectivity B) + (wiring layer thickness x γ / selectivity C) + D
It can be calculated from the formula of. As A, B and / or C increase, the thickness T of the protective film can be reduced.

Here, D is the thickness of the protective film left on the element region after plasma etching in consideration of the step in the wiring layer and the coverage and uniformity of the protective film. D is, for example, about 1 μm or more and 5 μm or less. Is set to. α, β, and γ are margin values for over-etching in consideration of the thickness of each layer and the uniformity of etching characteristics. α, β, and γ are set to, for example, 1.1 or more and 1.2 or less, respectively.

(substrate)
The substrate includes a first surface and a second surface, and also includes a plurality of element regions and a divided region that defines the element regions. The element region includes, for example, a semiconductor layer and a wiring layer. The divided region includes, for example, a semiconductor layer, an insulating film, and a metal material such as TEG (Test Element Group). A device chip is obtained by etching the substrate in the divided region.

The size of the substrate is not particularly limited, and is, for example, a maximum diameter of about 50 mm to 300 mm. The shape of the substrate is also not particularly limited, and is, for example, circular or square. Further, the substrate may be provided with notches such as an orientation flat (orifura) and a notch.

The semiconductor layer includes, for example, silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC) and the like. The thickness of the semiconductor layer in the element chip is not particularly limited, and may be, for example, 20 μm to 1000 μm, or 100 μm to 300 μm.

The wiring layer constitutes, for example, a semiconductor circuit, an electronic component element, a MEMS, or the like, and may include an insulating film, a metal material, a resin layer (for example, polyimide), a resist layer, an electrode pad, bumps, and the like. The insulating film may be included as a laminate (multilayer wiring layer or rewiring layer) with a metal material for wiring.

The shape of the divided region is not limited to a straight line, and may be set according to the shape of a desired element chip, and may be zigzag or wavy. Examples of the shape of the element chip include a rectangle and a hexagon.

The width of the divided region is not particularly limited, and may be appropriately set according to the size of the substrate and the element chip. The width of the divided region is, for example, 10 μm or more and 300 μm or less. The widths of the plurality of divided regions may be the same or different. A plurality of divided regions are usually arranged on the substrate. The pitch between adjacent divided regions is not particularly limited, and may be appropriately set according to the size of the substrate and the element chip.

FIG. 1 is a cross-sectional view schematically showing a substrate.
The substrate 10 includes a first surface 10X and a second surface 10Y, and also includes a plurality of element regions 101 and a division region 102 that defines the element regions 101. The element region 101 includes a semiconductor layer 11 and a wiring layer 12 laminated on the first surface 10X side of the semiconductor layer 11. The division region 102 includes a semiconductor layer 11 and an insulating film 14.

FIG. 2 is a cross-sectional view schematically showing a substrate (resin-coated substrate) provided with a protective film.
A protective film 40 is formed on the first surface 10X of the substrate 10.

(Resin layer)
A resin layer may be arranged on the second surface side of the substrate according to the present embodiment.
When manufacturing a plurality of element chips to be stacked in multiple stages such as a flash memory from one substrate, dicing is performed with the substrate attached to DAF (sometimes called a die bonding film). It may be said. In the present embodiment, DAF may be arranged as a resin layer on the second surface of the substrate.

The DAF is formed of, for example, a resin composition containing a resin and an inorganic filler.
Examples of the resin include photosensitive phenolic resins such as phenol / formaldehyde novolak resin, cresol / formaldehyde novolak resin, xylenol / formaldehyde novolak resin, resorcinol / formaldehyde novolak resin, and phenol-naphthol / formaldehyde novolak resin. The inorganic filler may be, for example, similar to the NIR-absorbing fillers listed above.

The thickness of the DAF is not particularly limited. The thickness of the DAF may be 10 μm to 100 μm or 20 μm to 50 μm from the viewpoint of handleability and the like. The DAF is, for example, larger than the substrate and smaller than the opening of the frame.

In the present embodiment, an adhesive layer may be arranged as a resin layer on the second surface of the substrate. The adhesive layer adheres the above-mentioned substrate (first substrate) to another substrate (second substrate). The second substrate supports, for example, the first substrate. The material of the second substrate is not particularly limited. Examples of the second substrate include a glass substrate, a resin substrate, a glass epoxy substrate, a ceramic substrate, a silicon substrate, and the like. The thickness of the second substrate is not particularly limited. The thickness of the second substrate may be, for example, 50 μm or more and 2 mm or less, and may be 100 μm or more and 500 μm or less.

The material of the adhesive layer is not particularly limited, and may be appropriately selected depending on the material of each substrate. Examples of the material of the adhesive layer include uncured or semi-cured UV curable resin, uncured or semi-cured thermosetting resin, pressure sensitive adhesive, thermoplastic resin and the like. Examples of the UV curable resin include acrylic resin and the like. Examples of the thermosetting resin include epoxy resin, polyimide, polyamide-imide and the like. Examples of the thermoplastic resin include polyester, polystyrene, polytetrafluoroethylene and the like. Examples of the pressure-sensitive adhesive include silicone resins and the like. The thickness of the adhesive layer is not particularly limited. The thickness of the adhesive layer may be, for example, 5 μm or more and 100 μm or less, and may be 5 μm or more and 15 μm or less.

[Manufacturing method of element chip]
The manufacturing method according to the present embodiment includes a preparatory step (S1) for preparing a substrate having a first surface and a second surface, and a protective film forming step (S1) for forming a protective film covering the first surface of the substrate. S2), an opening forming step (S3) of removing a part of the protective film by irradiating a laser beam to form an opening for exposing a part of the substrate, and etching the substrate exposed from the opening with plasma. Then, a step of individualizing the substrate and a step of removing the protective film (S5) for removing the protective film from the substrate after the individualizing step are provided. The individualization step includes a substrate etching step (S41) for etching the substrate and a resin etching step (S42) for etching the resin layer with plasma.
FIG. 3 is a flowchart showing a manufacturing method according to the present embodiment.

(1) Preparation step First, the above-mentioned substrate to be diced is prepared. From the viewpoint of handleability, the prepared substrate may be held by the transport carrier and used in the next step.

(Transport carrier)
The transport carrier includes a frame and a holding sheet fixed to the frame.

The frame is a frame having an opening having an area equal to or larger than the entire substrate, and has a predetermined width and a substantially constant thin thickness. The frame has enough rigidity to carry the holding sheet and the substrate while holding them. The shape of the opening of the frame is not particularly limited, but may be a polygon such as a circle, a rectangle, or a hexagon. Examples of the material of the frame include metals such as aluminum and stainless steel, and resins.

The material of the holding sheet is not particularly limited. Among them, the holding sheet preferably includes an adhesive layer and a flexible non-adhesive layer from the viewpoint that the substrate is easily attached.

The material of the non-adhesive layer is not particularly limited, and examples thereof include polyolefins such as polyethylene and polypropylene, and thermoplastic resins such as polyester such as polyvinyl chloride and polyethylene terephthalate. The resin film has a rubber component for adding elasticity (for example, ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), etc.), a plasticizer, a softener, an antioxidant, a conductive material, etc. Various additives may be blended. In addition, the thermoplastic resin may have a functional group such as an acrylic group that exhibits a photopolymerization reaction. The thickness of the non-adhesive layer is not particularly limited, and is, for example, 50 μm or more and 300 μm or less, preferably 50 μm or more and 150 μm or less.

The outer peripheral edge of the surface provided with the adhesive layer (adhesive surface) is attached to one surface of the frame and covers the opening of the frame. The substrate is held by the holding sheet by attaching one main surface (second surface) of the substrate to the portion of the adhesive surface exposed from the opening of the frame. The substrate may be held on the holding sheet via a die attach film (DAF).

The adhesive layer is preferably composed of an adhesive component whose adhesive strength is reduced by irradiation with ultraviolet rays (UV). As a result, when the element chip is picked up after plasma dicing, the element chip is easily peeled off from the adhesive layer by UV irradiation, which facilitates picking up. For example, the adhesive layer can be obtained by applying a UV-curable acrylic pressure-sensitive adhesive to one side of the non-adhesive layer to a thickness of 5 μm or more and 100 μm or less (preferably 5 μm or more and 15 μm or less).

FIG. 4A is a top view schematically showing a substrate held by a transport carrier. FIG. 4B is a cross-sectional view taken along the line AA shown in FIG. 4A.

The transport carrier 20 includes a frame 21 and a holding sheet 22 fixed to the frame 21. The frame 21 may be provided with a notch 21a or a corner cut 21b for positioning. The outer peripheral edge of the adhesive surface 22X is attached to one surface of the frame 21, and one main surface of the substrate 10 is attached to a portion of the adhesive surface 22X exposed from the opening of the frame 21. In FIGS. 4A and 4B, the substrate 10 is attached to the holding sheet 22 via the DAF 30. At the time of plasma processing, the holding sheet 22 is placed on the stage so that the stage installed in the plasma processing apparatus and the non-adhesive surface 22Y opposite to the adhesive surface 22X are in contact with each other.

FIG. 5 is a cross-sectional view schematically showing a substrate prepared by the preparation step according to the present embodiment. The DAF30 is arranged on the second surface 10Y side of the substrate. The substrate 10 is attached to the holding sheet 22 fixed to the frame via the DAF 30.

(2) Protective film forming step A protective film is formed on the first surface of the substrate to obtain a resin-coated substrate.

As the protective film, the resin composition is molded into a sheet, for example, and then the sheet is attached to the first surface, or the resin composition is applied by spin coating, spray coating, printing, or the like. It is formed by applying it to the first surface. After applying the resin composition, a drying treatment may be performed. The viscosity of the resin composition used for spin coating or spray coating is generally small. Therefore, the inorganic filler tends to precipitate in the protective film. Since the NIR-absorbing filler of the present embodiment has a small particle size, precipitation is suppressed even when such a coating method is used.

FIG. 6 is a cross-sectional view schematically showing the substrate after the protective film forming step according to the present embodiment. A protective film 40 is formed on the first surface 10X of the substrate 10.

(3) Aperture forming step A part of the protective film is removed to form an opening that exposes a part of the substrate.
The openings are formed by laser scribing the protective film in the split region, as well as the wiring layer. The removal of the wiring layer in the divided region may be performed in the substrate etching step described later. In this case, the condition for generating plasma for removing the wiring layer and the condition for generating plasma for etching the substrate may be different.

The wavelength of the laser beam used for laser scribing is 750 nm or more and 3000 nm or less in the near infrared region. In particular, it may be a laser beam having a wavelength of 800 nm or more and 1300 nm or less, specifically, a wavelength of 1064 nm or 1030 nm. This can be expected to improve productivity and cut costs.

The frequency of the laser beam is not particularly limited, but is, for example, 1 to 200 kHz, and the higher the frequency, the higher the speed processing becomes possible. The laser oscillation mechanism of the laser light is not particularly limited, and a semiconductor laser that uses a semiconductor as a medium for laser oscillation, a gas laser that uses a gas such as carbon dioxide (CO ₂ ) as a medium, a solid-state laser that uses YAG, and a fiber laser. And so on. The laser oscillator is also not particularly limited, but may be a pulse laser oscillator that oscillates a pulsed laser beam in that the thermal effect on the substrate is small.

The pulse width of the laser beam is not particularly limited, but is preferably 500 nanoseconds or less, and more preferably 200 nanoseconds or less, in that the thermal effect is smaller. In particular, it is preferable to use an ultrashort pulse laser beam having a pulse width of several femtoseconds (1 × ^10-15 seconds) to several picoseconds (1 × ^10-12 seconds). When the protective film is irradiated with ultrashort pulse laser light, the multiphoton absorption process becomes dominant. Therefore, the volume ratio of the NIR-absorbing filler can be reduced, and the NIR-absorbing filler can be more easily removed by washing.

When an ultrashort pulse laser beam having a wavelength in the near infrared region is used, heat absorption occurs only for an extremely short period of time that triggers the start of processing, and then the process shifts to the multiphoton absorption process. The NIR-absorbing filler also plays a role in supporting the heat absorption process that occurs immediately after the start of this processing. Therefore, the thermal effect of laser light irradiation tends to be small. In general, laser scribing utilizes the thermal vibration of electrons possessed by an object and is deeply related to the heat absorption process. Therefore, the heat effect is unavoidable.

FIG. 7 is a cross-sectional view schematically showing the substrate after the opening forming step according to the present embodiment. The protective film 40 and the wiring layer 12 in the divided region 102 are removed, and the semiconductor layer 11 is exposed from the opening.

(4) Individualization step The substrate exposed from the opening is etched by plasma to individualize the substrate. In the present embodiment, the DAF is etched by plasma (resin etching step) after the step of etching the substrate (board etching step).

An embodiment of the plasma processing apparatus used in the individualization step will be specifically described. FIG. 8 is a cross-sectional view schematically showing the structure of the plasma processing apparatus. In FIG. 8, the substrate and DAF are held by the transport carrier. The structure of the plasma processing apparatus is not limited to this.

(Plasma processing equipment)
The plasma processing apparatus 100 includes a stage 111. The transport carrier 20 is mounted on the stage 111 so that the surface of the holding sheet 22 holding the substrate 10 faces upward. The stage 111 has a size capable of mounting the entire transport carrier 20 on it. Above the stage 111, a cover 124 having a window portion 124W for exposing at least a part of the substrate 10 is arranged. A pressing member 107 for pressing the frame 21 is arranged on the cover 124 when the frame 21 is mounted on the stage 111. The pressing member 107 is preferably a member (for example, a coil spring or a resin having elasticity) that can make point contact with the frame 21. As a result, the distortion of the frame 21 can be corrected while suppressing the heat of the frame 21 and the cover 124 from affecting each other.

The stage 111 and the cover 124 are arranged in the vacuum chamber 103. The vacuum chamber 103 has a substantially cylindrical shape with an open upper portion, and the upper opening is closed by a dielectric member 108 which is a lid. Examples of the material constituting the vacuum chamber 103 include aluminum, stainless steel (SUS), and aluminum whose surface is anodized. Examples of the material constituting the dielectric member 108 include dielectric materials such as yttrium oxide (Y ₂ O ₃ ), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), and quartz (SiO ₂ ). A first electrode 109 as an upper electrode is arranged above the dielectric member 108. The first electrode 109 is electrically connected to the first high frequency power supply 110A. The stage 111 is arranged on the bottom side in the vacuum chamber 103.

A gas introduction port 103a is connected to the vacuum chamber 103. A process gas source 112 and an ashing gas source 113, which are supply sources of plasma generating gas (process gas), are connected to the gas introduction port 103a by pipes, respectively. Further, the vacuum chamber 103 is provided with an exhaust port 103b, and the exhaust port 103b is connected to a decompression mechanism 114 including a vacuum pump for exhausting the gas in the vacuum chamber 103 to reduce the pressure. With the process gas supplied into the vacuum chamber 103, high-frequency power is supplied from the first high-frequency power source 110A to the first electrode 109, so that plasma is generated in the vacuum chamber 103.

The stage 111 includes a substantially circular electrode layer 115, a metal layer 116, a base 117 that supports the electrode layer 115 and the metal layer 116, and an outer peripheral portion 118 that surrounds the electrode layer 115, the metal layer 116, and the base 117, respectively. To be equipped. The outer peripheral portion 118 is made of a metal having conductivity and etching resistance, and protects the electrode layer 115, the metal layer 116, and the base 117 from plasma. An annular outer ring 129 is arranged on the upper surface of the outer peripheral portion 118. The outer peripheral ring 129 has a role of protecting the upper surface of the outer peripheral portion 118 from plasma. The electrode layer 115 and the outer ring 129 are made of, for example, the above-mentioned dielectric material.

Inside the electrode layer 115, an electrode for electrostatic adsorption (Electrostatic Chuck) (hereinafter referred to as ESC electrode 119) and a second electrode 120 electrically connected to the second high frequency power supply 110B are arranged. Has been done. A DC power supply 126 is electrically connected to the ESC electrode 119. The electrostatic adsorption mechanism is composed of an ESC electrode 119 and a DC power supply 126. The holding sheet 22 is pressed against the stage 111 and fixed by the electrostatic adsorption mechanism. Hereinafter, a case where an electrostatic adsorption mechanism is provided as a fixing mechanism for fixing the holding sheet 22 to the stage 111 will be described as an example, but the present invention is not limited thereto. Fixing of the holding sheet 22 to the stage 111 may be performed by a clamp (not shown).

The metal layer 116 is made of, for example, aluminum or the like having an alumite coating formed on its surface. A refrigerant flow path 127 is formed in the metal layer 116. The refrigerant flow path 127 cools the stage 111. By cooling the stage 111, the holding sheet 22 mounted on the stage 111 is cooled, and the cover 124 whose part is in contact with the stage 111 is also cooled. As a result, the substrate 10 and the holding sheet 22 are prevented from being damaged by being heated during the plasma treatment. The refrigerant in the refrigerant flow path 127 is circulated by the refrigerant circulation device 125.

A plurality of support portions 122 penetrating the stage 111 are arranged near the outer periphery of the stage 111. The support portion 122 supports the frame 21 of the transport carrier 20. The support portion 122 is lifted and driven by the first lifting mechanism 123A. When the transport carrier 20 is transported into the vacuum chamber 103, it is delivered to the support portion 122 that has risen to a predetermined position. The transport carrier 20 is placed in a predetermined position on the stage 111 by lowering the upper end surface of the support portion 122 to the same level as or lower than the stage 111.

A plurality of elevating rods 121 are connected to the end of the cover 124 to allow the cover 124 to be elevated and lowered. The elevating rod 121 is elevated and driven by the second elevating mechanism 123B. The operation of raising and lowering the cover 124 by the second raising and lowering mechanism 123B can be performed independently of the first raising and lowering mechanism 123A.

The control device 128 includes a first high-frequency power supply 110A, a second high-frequency power supply 110B, a process gas source 112, an ashing gas source 113, a pressure reducing mechanism 114, a refrigerant circulation device 125, a first lifting mechanism 123A, and a second lifting mechanism. It controls the operation of the elements constituting the plasma processing apparatus 100 including the 123B and the electrostatic adsorption mechanism. FIG. 9 is a block diagram of the plasma processing apparatus used in the present embodiment.

The etching of the substrate 10 is performed in a state where the transport carrier 20 holding the substrate 10 is carried into the vacuum chamber and the substrate 10 is placed on the stage 111.
When the substrate 10 is carried in, the cover 124 is raised to a predetermined position in the vacuum chamber 103 by driving the elevating rod 121. A gate valve (not shown) is opened to carry the transport carrier 20. The plurality of support portions 122 are standing by in an elevated state. When the transport carrier 20 reaches a predetermined position above the stage 111, the transport carrier 20 is delivered to the support portion 122. The transport carrier 20 is delivered to the upper end surface of the support portion 122 so that the adhesive surface 22X of the holding sheet 22 faces upward.

When the transport carrier 20 is delivered to the support 122, the vacuum chamber 103 is placed in a sealed state. Next, the support portion 122 starts descending. The transport carrier 20 is placed on the stage 111 by lowering the upper end surface of the support portion 122 to the same level as or lower than the stage 111. Subsequently, the elevating rod 121 is driven. The elevating rod 121 lowers the cover 124 to a predetermined position. At this time, the distance between the cover 124 and the stage 111 is adjusted so that the pressing member 107 arranged on the cover 124 can make point contact with the frame 21. As a result, the frame 21 is pressed by the pressing member 107, the frame 21 is covered by the cover 124, and the substrate 10 is exposed from the window portion 124W.

The cover 124 is, for example, a donut shape having a substantially circular outer contour, and has a constant width and a thin thickness. The diameter of the window portion 124W is smaller than the inner diameter of the frame 21, and the outer diameter thereof is larger than the outer diameter of the frame 21. Therefore, when the transport carrier 20 is mounted at a predetermined position on the stage and the cover 124 is lowered, the cover 124 can cover the frame 21. At least a part of the substrate 10 is exposed from the window portion 124W.

The cover 124 is made of, for example, a dielectric such as ceramics (for example, alumina, aluminum nitride, etc.) or quartz, or a metal such as aluminum or aluminum whose surface is anodized. The pressing member 107 may be made of a resin material in addition to the above-mentioned dielectric and metal.

After the transport carrier 20 is delivered to the support portion 122, a voltage is applied from the DC power supply 126 to the ESC electrode 119. As a result, the holding sheet 22 comes into contact with the stage 111 and is electrostatically attracted to the stage 111 at the same time. The application of the voltage to the ESC electrode 119 may be started after the holding sheet 22 is placed on the stage 111 (after contact with the stage 111).

When the etching is completed, the gas in the vacuum chamber 103 is discharged and the gate valve is opened. The transport carrier 20 that holds the plurality of element chips is carried out from the plasma processing device 100 by the transport mechanism that has entered from the gate valve. When the transport carrier 20 is carried out, the gate valve is quickly closed. The carry-out process of the transport carrier 20 may be performed in the reverse procedure of the procedure for mounting the transport carrier 20 on the stage 111 as described above. That is, after raising the cover 124 to a predetermined position, the voltage applied to the ESC electrode 119 is set to zero to release the adsorption of the transport carrier 20 to the stage 111, and the support portion 122 is raised. After the support portion 122 rises to a predetermined position, the transport carrier 20 is carried out.

(4-1) Substrate Etching Step The conditions for generating plasma (first plasma P1) for etching the semiconductor layer are set according to the material of the semiconductor layer and the like.
The semiconductor layer is plasma etched, for example, by a Bosch process. In the Bosch process, the semiconductor layer is etched perpendicular to the depth direction. When the semiconductor layer contains Si, the Bosch process digs the semiconductor layer in the depth direction by sequentially repeating the deposition step, the deposition film etching step, and the Si etching step.

In the deposition step, for example, while supplying C ₄ F ₈ as a process gas at 150 sccm to 250 sccm, the pressure in the vacuum chamber is adjusted to 15 Pa to 25 Pa, and the power input from the first high frequency power source to the first electrode is applied. The processing is performed under the condition that the input power from the second high frequency power source to the second electrode is 0 W to 50 W and the processing is performed for 2 seconds to 15 seconds.

In the deposition film etching step, for example, while supplying SF ₆ as a process gas at 200 sccm to 400 sccm, the pressure in the vacuum chamber is adjusted to 5 Pa to 15 Pa, and the power input from the first high frequency power source to the first electrode is applied. The processing is performed under the condition that the input power from the second high frequency power source to the second electrode is 300 W to 1000 W and the processing is performed for 2 seconds to 10 seconds.

In the Si etching step, for example, while supplying SF ₆ as a process gas at 200 sccm to 400 sccm, the pressure in the vacuum chamber is adjusted to 5 Pa to 15 Pa, and the power input from the first high frequency power source to the first electrode is 1500 W. It is carried out under the condition that the input power from the second high frequency power source to the second electrode is 50 W to 500 W and the processing is performed for 10 seconds to 20 seconds.

By repeating the deposition step, the deposition film etching step, and the Si etching step under the above conditions, the semiconductor layer containing Si is etched perpendicularly to the depth direction at a rate of 10 μm / min to 20 μm / min. obtain.

The wiring layer containing the metal material can be etched by the plasma (third plasma P3) generated under the following conditions. For example, the pressure in the vacuum chamber is adjusted to 0.2 Pa to 1.5 Pa while supplying a mixed gas of CF ₄ and Ar (CF ₄ : Ar = 1: 4) as a process gas at 150 sccm to 250 sccm. A high frequency power of 1500 W to 2500 W and a frequency of 13.56 MHz is supplied from the first high frequency power supply to the first electrode, and 500 W to 1800 W and a frequency of 100 kHz or more (for example, 400 kHz to 400 kHz) are supplied from the second high frequency power supply to the second electrode. High frequency power of 500 kHz or 13.56 MHz) is input.

FIG. 10 is a cross-sectional view schematically showing the substrate after the substrate etching step according to the present embodiment. The semiconductor layer 11 in the divided region 102 is removed, and the DAF 30 is exposed from the opening.

(4-2) Resin Etching Step Next, the DAF exposed from the opening is etched, and the DAF is divided so as to correspond to the element chip. As a result, a plurality of element chips can be obtained in a state of being held by the holding sheet via the DAF divided for each element chip.

The plasma processing apparatus used in the substrate etching step and the resin etching step may be the same or different. If the same plasma processing apparatus is used, both etching steps may be performed consecutively.

The conditions for generating the plasma for etching the DAF (second plasma P2) are set according to the material of the DAF to be etched.
When the DAF is formed of a resin composition containing a resin and an inorganic filler, the second plasma P2 is preferably generated using a process gas containing oxygen and fluorine. Oxygen radicals generated from gas containing oxygen are highly reactive with organic materials such as resins. Fluorine radicals generated from a gas containing fluorine are highly reactive with inorganic fillers. Therefore, when a process gas containing oxygen and fluorine is used, the DAF containing the inorganic filler can be efficiently etched, and the scattering of the inorganic filler is easily suppressed. Examples of the process gas containing oxygen and fluorine include a mixed gas of oxygen gas (O ₂ ) and fluorine-containing gas (SF ₆ , CF ₄ ). The flow rate ratio of the fluorine-containing gas in the mixed gas is, for example, 5% or more.

As another condition for generating the second plasma P2, for example, it is preferable that the pressure in the vacuum chamber is 5 Pa to 10 Pa. Further, it is preferable to apply a high frequency power of 500 W to 1000 W to the second electrode to apply a high bias voltage to the stage. As a result, the ionicity of the etching is increased, and the scattering of the inorganic filler is more likely to be suppressed. However, as the bias voltage increases, the temperature of the DAF on the stage tends to increase. Therefore, it is preferable to cool the stage to, for example, 15 ° C. or lower to maintain the temperature of the DAF during etching of the DAF to 50 ° C. or lower.

Specifically, the etching of DAF can be performed under the following conditions. While supplying a mixed gas of oxygen gas (flow rate 350 sccm) and SF ₆ (flow rate 50 sccm) into the vacuum chamber as a process gas, the pressure in the vacuum chamber is maintained at 5 Pa to 10 Pa. A high frequency power of 3000 W to 5000 W is applied to the first electrode, and a high frequency power of 500 W to 1000 W is applied to the stage. As a result, the DAF is etched at an etching rate of about 1.5 μm / min to 4 μm / min.

FIG. 11 is a cross-sectional view schematically showing a substrate (element chip) after the resin etching step according to the present embodiment. The DAF 30 in the divided region 102 is removed, and a plurality of element chips 200 are formed.

(5) Protective film removing step After the individualizing step, the protective film is removed from the substrate. In the present embodiment, the protective film can be removed by contacting a cleaning liquid containing a solvent that dissolves the resin to dissolve at least a part of the protective film. Since the NIR-absorbing filler in the protective film has a small average particle size and is uniformly dispersed in the protective film, it is easily washed away together with the dissolved resin and removed from the substrate.

The solvent contained in the cleaning liquid may be appropriately selected depending on the resin forming the protective film. Examples of the solvent for dissolving the water-soluble resin include propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK) isopropyl alcohol (IPA), ethanol, acetone, and water. The cleaning liquid contains one of these types alone or two or more types. In particular, it is desirable that the cleaning liquid contains PGMEA because it is difficult to dissolve the holding sheet.

The method of bringing the cleaning liquid into contact with the individualized substrate (that is, the element chip) is not particularly limited. For example, the cleaning liquid may be dropped from the first surface side of the element chip.

FIG. 12 is a cross-sectional view schematically showing the element chip after the protective film removing step according to the present embodiment. The NIR-absorbing filler contained in the protective film 40 has been removed together with the resin.

(6) Pickup process The element chip is removed from the holding sheet together with the divided DAF.
The element chip is pushed up from the non-adhesive surface side of the holding sheet together with the holding sheet and the DAF by a push-up pin, for example. As a result, at least a part of the element chip is lifted from the holding sheet. After that, the element chip is removed from the holding sheet by the pickup device.

According to the method for manufacturing a device chip of the present invention, a desired device chip can be obtained with high quality, which is useful as a method for manufacturing a device chip from various substrates. According to the resin composition and the resin-coated substrate of the present invention, a desired element chip can be obtained with high quality, and therefore, it is suitably used in a method for producing various element chips.

10: Substrate 10X: First surface 10Y: Second surface 101: Element area 102: Division area 11: Semiconductor layer 12: Wiring layer 14: Insulation film 20: Transport carrier 21: Frame 21a: Notch 21b: Corner cut 22 : Holding sheet 22X: Adhesive surface 22Y: Non-adhesive surface 30: DAF
40: Protective film 100: Plasma processing device 103: Vacuum chamber 103a: Gas inlet 103b: Exhaust port 108: Dielectric member 109: First electrode 110A: First high frequency power supply 110B: Second high frequency power supply 111: Stage 112: Process gas source 113: Ashing gas source 114: Decompression mechanism 115: Electrode layer 116: Metal layer 117: Base 118: Outer peripheral part 119: ESC electrode 120: Second electrode 121: Lifting rod 122: Support part 123A: First elevating mechanism 123B: Second elevating mechanism 124: Cover 124W: Window 125: Refrigerator circulation device 126: DC power supply 127: Refrigerator flow path 128: Control device 129: Outer ring 200: Element chip

Claims (13)

A preparatory step for preparing a substrate having a first surface and a second surface opposite to the first surface, and
A protective film forming step of forming a protective film covering the first surface of the substrate, and
An opening forming step of removing a part of the protective film by irradiating a laser beam to form an opening that exposes a part of the substrate.
The individualization step of etching the substrate exposed from the opening with plasma to individualize the substrate, and
After the individualization step, a protective film removing step of removing the protective film from the substrate is provided.
The protective film contains a resin and a filler, and contains
The average particle size of the filler is 10 nm or more and 1 μm or less.
The filler has near-infrared absorption performance and
The laser beam is a method for manufacturing an element chip, which includes a wavelength in the near infrared region. The filler has an electromagnetic wave absorption performance having a wavelength of 800 nm or more and 1300 nm or less.
The method for manufacturing an element chip according to claim 1, wherein the laser beam includes a wavelength of 800 nm or more and 1300 nm or less. The method for producing an element chip according to claim 1 or 2, wherein the filler contains at least one selected from the group consisting of a carbon material, a metal carbonate, a metal hydroxide, and a metal silicate. The method for manufacturing an element chip according to any one of claims 1 to 3, wherein the mass ratio of the filler to the protective film is 0.1% or more and 40% or less. The method for manufacturing an element chip according to any one of claims 1 to 4, wherein the laser beam is an ultrashort pulse laser beam. The element chip according to any one of claims 1 to 5, wherein in the protective film forming step, a resin composition containing the resin and the filler is applied to the substrate by a spin coating method or a spray method. Production method. A resin layer is arranged on the second surface of the substrate.
The method for manufacturing an element chip according to any one of claims 1 to 6, wherein in the individualization step, the substrate is etched and then the resin layer is etched by plasma. A substrate containing a semiconductor and a protective film covering the substrate are provided.
The protective film contains a resin and a filler, and contains
The average particle size of the filler is 10 nm or more and 1 μm or less.
The filler is a resin-coated substrate having near-infrared absorbing performance. The resin-coated substrate according to claim 8, wherein the filler contains at least one selected from the group consisting of carbon materials, metal carbonates, metal hydroxides and metal silicates. The resin-coated substrate according to claim 8 or 9, wherein the mass ratio of the filler to the protective film is 0.1% or more and 40% or less. A resin composition for forming a protective film for coating a substrate containing a semiconductor.
Contains resin and filler,
The average particle size of the filler is 10 nm or more and 1 μm or less.
The filler is a resin composition having near infrared ray absorbing performance. The resin composition according to claim 11, wherein the filler contains at least one selected from the group consisting of carbon materials, metal carbonates, metal hydroxides and metal silicates. The resin composition according to claim 11 or 12, wherein the mass ratio of the filler to the non-volatile component of the resin composition is 0.1% or more and 40% or less.

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