Composition for transparent adhesive, film-like transparent adhesive, method for manufacturing member with cured layer of transparent adhesive, electronic component, and method for manufacturing the same

Abstract

The present invention pertains to: a transparent adhesive composition which contains an epoxy resin (A), an epoxy resin curing agent (B), and a phenoxy resin (C), and in which the epoxy resin curing agent (B) satisfies (1) and (2); a film-like transparent adhesive obtained by processing said composition; and a method for manufacturing a transparent adhesive cured layer-provided member, a method for manufacturing an electronic component, and an electronic component, all of which using said film-like transparent adhesive.　(1) Being a powder and having a particle diameter (d90) at a cumulative distribution frequency of 90% of 2.0 μm or less. (2) Having a solubility of 0.1 g or less with respect to 100 g of methyl ethyl ketone at 25°C.

Description

Technical Field

[0001] The present invention relates to a composition for a transparent adhesive, a film-shaped transparent adhesive, a method for manufacturing a member with a transparent adhesive cured layer, an electronic component, and a method for manufacturing the same.

Background Art

[0002] In recent years, due to the progress of 3D sensing and high resolution of electronic devices, the demand for optical devices such as optical lenses, optical fibers, optical waveguides, optical isolators, and semiconductor lasers has been increasing in the automotive, mobile, security, industrial fields, etc. Among optical devices, transparent members such as lenses and glass are mounted via a transparent adhesive (transparent adhesive). Conventionally, a paste-shaped adhesive has been used as the above-mentioned transparent adhesive. However, the paste-shaped adhesive is likely to cause problems such as oozing out from the bonding site during bonding. Therefore, recently, film-shaped adhesives have been increasingly used as transparent adhesives.

[0003] In addition, the film-shaped transparent adhesive is also used as a die attach film in the manufacture of semiconductor devices for bonding a wiring board and a semiconductor chip and bonding between semiconductor chips (so-called die attach).

[0004] Patent Document 1 discloses a film-shaped adhesive containing a binder resin (A), an epoxy resin (B), a thermosetting agent (C), and a filler (D), wherein the content of the epoxy resin (B) is 100 to 1000 parts by mass with respect to 100 parts by mass of the binder resin (A), the average particle diameter of the filler (D) is 50 nm or less, the total light transmittance in a D65 standard light source is 70% or more, and the haze value is 50% or less. As a specific embodiment of this film-shaped adhesive, a form using an acrylic resin as the binder resin is shown.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent No. 6336905 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] When mounting a transparent member on an optical device or the like, an alignment mark is provided on a part of the transparent member, a film-like transparent adhesive is bonded onto this alignment mark by thermocompression bonding or the like, and while optically recognizing the alignment mark through the bonded film-like transparent adhesive, the transparent member is bonded to another member via the film-like transparent adhesive. In this case, the finer the alignment mark is, the higher the visibility of the alignment mark (high transparency of the adhesive) is required for the film-like transparent adhesive. Also, when the film-like transparent adhesive is used for bonding a transparent member, it is required to maintain the desired transparency even after the adhesive is cured. Further, the film-like transparent adhesive can be cured in a state where it is bonded to a transparent member or the like and function as a protective film for the transparent member. Even in such use as a protective film, ensuring the visibility of the alignment mark through the protective film may be required in the mounting or the like of the transparent member with the protective film.

[0007] The film-like transparent adhesive is required to have a property of maintaining its function as an adhesive until use, that is, storage stability. However, an uncured film-like transparent adhesive may gradually proceed with a curing reaction when left at room temperature (25°C), for example, and may not be able to exhibit the desired adhesive performance. Therefore, improving storage stability is important in the performance of the film-like transparent adhesive.

[0008] In the case of a film - shaped transparent adhesive using an epoxy resin, in order to enhance storage stability, it is known to use a solid - state curing agent for the epoxy resin at normal temperature. However, according to the study by the present inventors, when the heat - curing temperature is set to a relatively low temperature (for example, about 120°C) and a large amount of the curing agent is contained to efficiently promote the curing reaction, the transparency decreases, and it has been found that poor recognition of alignment marks occurs through this cured film. The present invention has been made in view of the problems of the above - mentioned prior art, and an object thereof is to provide a film - shaped transparent adhesive that exhibits sufficient transparency after curing and has high storage stability at normal temperature, a method for manufacturing a member with a transparent adhesive cured layer using the same, an electronic component, and a method for manufacturing an electronic component. Another object of the present invention is to provide a composition for a transparent adhesive suitable for preparing the above - mentioned film - shaped transparent adhesive.

Means for Solving the Problems

[0009] As a result of intensive studies in view of the above problems, the present inventors adopted a combination of an epoxy resin, an epoxy resin curing agent, and a phenoxy resin as raw materials for the film - shaped transparent adhesive, made the epoxy resin curing agent in the form of powder with a specific particle size, and used a curing agent with low solubility in a solvent, and found that the above problems can be solved. The present invention has been completed through further studies based on these findings.

[0010] The above problems of the present invention are solved by the following means. 〔1〕 A composition for a transparent adhesive containing an epoxy resin (A), an epoxy resin curing agent (B), and a phenoxy resin (C), wherein the epoxy resin curing agent (B) satisfies the following (1) and (2). (1) It is in powder form and the particle size (d90) at a cumulative distribution frequency of 90% is 2.0 μm or less (2) The solubility in 100 g of methyl ethyl ketone at 25°C is 0.1 g or less 〔2〕 A transparent adhesive composition according to [1], which contains a silica filler (D1), the silica filler (D1) satisfies the following (3) and (4), and the proportion of the content of the silica filler (D1) in the total content of the epoxy resin (A), the epoxy resin curing agent (B), the phenoxy resin (C) and the silica filler (D1) is 10 to 50% by mass. (3) The average particle size (d50) is 0.01 to 0.3 μm (4) The particle size (d90) at a cumulative distribution frequency of 90% is 1.0 μm or less [3] The transparent adhesive composition according to [1] or [2], wherein the epoxy resin curing agent (B) contains a dicyandiamide compound, an imidazole compound, or a hydrazide compound. [4] The transparent adhesive composition according to any one of [1] to [3], wherein the content of the epoxy resin curing agent (B) with respect to 100 parts by mass of the epoxy resin (A) is 4 to 20 parts by mass. [5] A film-like transparent adhesive formed by forming a transparent adhesive composition according to any one of [1] to [4]. [6] The film-like transparent adhesive according to [5], wherein the haze value after thermosetting of the film-like transparent adhesive is 50% or less. [7] The film-like transparent adhesive according to [5] or [6], wherein when the film-like transparent adhesive before thermosetting is heated at a heating rate of 5 °C / min from 25 °C, the melt viscosity at 120 °C reaches a range of 100 to 10,000 Pa·s. [8] The film-like transparent adhesive according to any one of [5] to [7], which has a thickness of 1 to 100 μm. [9] A method for manufacturing a member with a transparent adhesive cured layer, which includes thermocompression bonding a film-like transparent adhesive according to any one of [5] to [8] onto an adherend member and thermosetting the film-like transparent adhesive.

[10] A method for manufacturing an electronic component, comprising: A first step of thermocompression bonding the film-like transparent adhesive according to any one of [5] to [8] on one surface of a wafer and providing a dicing tape through the film-like transparent adhesive; A second step of obtaining a wafer chip with a transparent adhesive layer on the dicing tape by integrally dicing the wafer and the film-like transparent adhesive; A third step of removing the dicing tape from the transparent adhesive layer and thermocompression bonding the wafer chip with the transparent adhesive layer and other members through the transparent adhesive layer; A fourth step of thermosetting the transparent adhesive layer; A method for manufacturing an electronic component including the above steps. 〔11〕 An electronic component in which the space between the wafer chip and the wiring board and / or between the wafer chips is bonded by a thermoset of the film-like transparent adhesive according to any one of [5] to [8].

[0011] In the present invention, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In the present invention, (meth)acrylic means one or both of acrylic and methacrylic. The same applies to (meth)acrylate.

Effects of the Invention

[0012] The film-like transparent adhesive of the present invention is excellent in transparency even after thermosetting and also excellent in storage stability at room temperature. The composition for a transparent adhesive of the present invention can obtain the above film-like transparent adhesive by forming a film therefrom. According to the method for manufacturing a member with a transparent adhesive cured layer of the present invention, a member having a cured layer (such as a protective layer) excellent in transparency can be obtained. According to the method for manufacturing an electronic component of the present invention, an electronic component of the present invention having a cured layer excellent in transparency can be obtained.

Brief Description of the Drawings

[0013]

Figure 1

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MODE FOR CARRYING OUT THE INVENTION

[0014] <<Composition for Transparent Adhesive>> The composition for a transparent adhesive of the present invention contains an epoxy resin (A), an epoxy resin curing agent (B), and a phenoxy resin (C). In the composition for a transparent adhesive of the present invention, the epoxy resin curing agent (B) satisfies the following (1) and (2). (1) It is in powder form and the particle size (d90) at a cumulative distribution frequency of 90% is 2.0 μm or less (2) At 25°C, the solubility in 100 g of methyl ethyl ketone (MEK) is 0.1 g or less (that is, the solubility in MEK at 25°C is 0.1 g / 100 g-MEK or less (the mass of the epoxy resin curing agent dissolved in 100 g of MEK at 25°C is 0.1 g or less))

[0015] In the present invention, when the term "transparent" is used, the degree of transparency is not particularly limited as long as it has transparency. For example, it may be colorless and transparent, colored and transparent, or translucent. In the present invention, the epoxy resin curing agent (B) being in powder form means that the epoxy resin curing agent (B) is in the form of solid particles at normal temperature (25 °C, the same hereinafter). The particle size (d90) at the cumulative distribution frequency of 90% of the epoxy resin curing agent (B) is 2.0 μm or less. This particle size (d90) at the cumulative distribution frequency of 90% means the particle size when the cumulative becomes 90% when the total volume of the particles is taken as 100% in the cumulative distribution measured by the laser diffraction / scattering method. As the epoxy resin curing agent (B), commercially available products can also be used, and if necessary, by performing pulverization treatment, sieving, etc., the above-mentioned "particle size (d90) at the cumulative distribution frequency of 90% is 2.0 μm or less" can also be satisfied. The solubility of the epoxy resin curing agent (B) in MEK at normal temperature (25 °C) is 0.1 g / 100 g-MEK or less. This solubility means the maximum amount of the epoxy resin curing agent (B) dissolved in 100 g of MEK at normal temperature. Here, MEK is a commonly used solvent for the liquid composition obtained by dissolving an epoxy resin. Therefore, the solubility of the epoxy resin curing agent (B) in MEK at normal temperature being 0.1 g / 100 g-MEK or less indicates that the epoxy resin curing agent (B) is difficult to dissolve in the transparent adhesive composition. Even if a solvent other than MEK is used in the transparent adhesive composition, as long as the solubility of the epoxy resin curing agent (B) in MEK at normal temperature is 0.1 g / 100 g-MEK or less, this epoxy resin curing agent (B) is also difficult to dissolve in the solvent, similar to that in MEK.

[0016] From the viewpoints of storage stability and transparency, the particle size (d90) at the cumulative distribution frequency of 90% of the epoxy resin curing agent (B) is preferably 0.05 to 2.0 μm, more preferably 0.1 to 2.0 μm, still more preferably 0.2 to 2.0 μm, and particularly preferably 0.3 to 1.0 μm. From the viewpoints of storage stability and transparency, the solubility of the epoxy resin curing agent (B) in MEK at room temperature is preferably 0.005 to 0.1 g / 100 g-MEK, more preferably 0.005 to 0.01 g / 100 g-MEK.

[0017] The composition for a transparent adhesive of the present invention may further contain an inorganic filler (D). The inorganic filler (D) will be described later.

[0018] Hereinafter, each component contained in the composition for a transparent adhesive will be described.

[0019] (Epoxy resin (A)) The above epoxy resin (A) is a thermosetting resin having an epoxy group, and the epoxy equivalent is 500 g / eq or less. The epoxy resin (A) may be any of a liquid, a solid, or a semi-solid. In the present invention, a liquid means that the softening point is less than 25°C, a solid means that the softening point is 60°C or higher, and a semi-solid means that the softening point is between the softening point of the above liquid and the softening point of the solid (25°C or higher and less than 60°C). From the viewpoint of obtaining a film-like transparent adhesive that can reach a low melt viscosity in a suitable temperature range (for example, 60 to 120°C), the softening point of the epoxy resin (A) used in the present invention is preferably 100°C or lower. In the present invention, the softening point is a value measured by the softening point test (ring and ball method) (measurement conditions: in accordance with JIS-2817).

[0020] In the epoxy resin (A) used in the present invention, from the viewpoint of increasing the crosslink density of the thermoset of the film-like transparent adhesive, the epoxy equivalent is preferably 150 to 450 g / eq. In the present invention, the epoxy equivalent means the number of grams (g / eq) of a resin containing 1 gram equivalent of epoxy groups. The mass average molecular weight of the epoxy resin (A) is usually preferably less than 10,000, more preferably 5,000 or less. There is no particular limitation on the lower limit value, but 300 or more is practical. The mass average molecular weight is a value by GPC (Gel Permeation Chromatography) analysis.

[0021] As the skeleton of the epoxy resin (A), phenol novolac type, orthocresol novolac type, cresol novolac type, dicyclopentadiene type, biphenyl type, fluorene bisphenol type, triazine type, naphthol type, naphthalene diol type, triphenylmethane type, tetraphenyl type, bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type, trimethylolmethane type, etc. can be mentioned. Among these, from the viewpoint of obtaining a film-like transparent adhesive having low crystallinity of the resin and good appearance, triphenylmethane type, bisphenol A type, cresol novolac type, and orthocresol novolac type are preferable. These may be used alone or in combination of two or more, and a combination of triphenylmethane type and bisphenol A type is preferable.

[0022] The content of the epoxy resin (A) is preferably 3 to 80 parts by mass, more preferably 30 to 70 parts by mass, and still more preferably 40 to 70 parts by mass in 100 parts by mass of the total content of the components constituting the film-like transparent adhesive (specifically, components other than the solvent) in the composition for a transparent adhesive of the present invention. By setting the content within the above preferable range, the storage stability and transparency can be enhanced. Further, by setting it below the above preferable upper limit value, the generation of oligomer components can be suppressed, and the change in the film state (film tackiness, etc.) can be made less likely to occur due to a slight temperature change.

[0023] (Epoxy resin curing agent (B)) The above epoxy resin curing agent (B) is not particularly limited as long as it satisfies the above (1) and (2), and any curing agent such as amines, acid anhydrides, polyhydric phenols, etc. can be used. In the present invention, from the viewpoint of obtaining a film-like transparent adhesive having high storage stability, it is preferable to use a latent curing agent. By using a latent curing agent, it is also possible to obtain a film-like transparent adhesive having a low melt viscosity, exhibiting thermosetting properties at a high temperature exceeding a certain temperature, and having rapid curing properties. Examples of the latent curing agent include dicyandiamide compounds, imidazole compounds, curing catalyst composite polyhydric phenol compounds, hydrazide compounds, boron trifluoride - amine complexes, amine imide compounds, polyamine salts, and modified products and microcapsule - type products thereof. Dicyandiamide compounds, imidazole compounds, and hydrazide compounds are preferred. These may be used alone or in combination of two or more. From the viewpoint of having more excellent latency (excellent stability at room temperature and exhibiting curability upon heating) and a faster curing rate, it is more preferable to use an imidazole compound.

[0024] From the viewpoints of storage stability and transparency, the proportion of the content of the epoxy resin curing agent (B) in the total of the contents of the epoxy resin (A), epoxy resin curing agent (B), phenoxy resin (C), and inorganic filler (D) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, still more preferably 2 to 15% by mass, still more preferably 2 to 10% by mass, and particularly preferably 3 to 6% by mass.

[0025] The content of the epoxy resin curing agent (B) with respect to 100 parts by mass of the epoxy resin (A) is preferably 0.5 to 100 parts by mass, more preferably 1 to 80 parts by mass, still more preferably 2 to 50 parts by mass, still more preferably 4 to 20 parts by mass, and particularly preferably 4 to 12 parts by mass. By setting the content to be not less than the above - mentioned preferable lower limit value, the curing time can be made shorter. On the other hand, by setting it to be not more than the above - mentioned preferable upper limit value, the residual amount of the excessive curing agent in the film - like transparent adhesive can be suppressed. As a result, the adsorption of moisture by the residual curing agent can be suppressed, and the reliability of the semiconductor device can be improved. Further, from the viewpoint of enhancing low - temperature curability, it is preferable to be within the above range.

[0026] (Phenoxy resin (C)) The phenoxy resin (C) is a component that suppresses the film tackiness at room temperature (25°C) and imparts film - forming property (film - forming ability) when forming a film - like transparent adhesive. The above-mentioned phenoxy resin (C) preferably has an elastic modulus at room temperature (25°C) of 500 MPa or more. The elastic modulus of the above-mentioned phenoxy resin (C) at room temperature (25°C) is preferably 2,000 MPa or less. The elastic modulus at room temperature (25°C) can be 1,000 to 2,000 MPa, or can be 1,500 to 2,000 MPa. The elastic modulus at room temperature (25°C) can be determined by the method described below. When the transparent adhesive composition contains two or more kinds of phenoxy resins, the elastic modulus at room temperature (25°C) can be determined using a film prepared by blending phenoxy resins at the mixing ratio constituting the transparent adhesive composition as the phenoxy resin film for measuring the elastic modulus at room temperature in the method described below. --Method for measuring elastic modulus at room temperature (25°C)-- 30 parts by mass of various phenoxy resins and 70 parts by mass of MEK are heated and stirred at a temperature of 110°C for 2 hours in a 500 ml separable flask to obtain a resin varnish. Next, this resin varnish is applied onto a release-treated PET film (release film) with a thickness of 38 μm, and dried by heating at 130°C for 10 minutes to obtain a phenoxy resin film having a length of 300 mm, a width of 200 mm, and a thickness of 100 μm. This phenoxy resin film is cut into a size of 5 mm × 17 mm, and using a dynamic viscoelasticity measuring device (trade name: Rheogel-E4000F, manufactured by UBM Co., Ltd.), measurement is performed under the conditions of a measurement temperature range of 0 to 100°C, a temperature rising rate of 5°C / min, and a frequency of 1 Hz, and the value of the elastic modulus at 25°C is obtained.

[0027] As the above-mentioned phenoxy resin (C), the mass average molecular weight is usually 10,000 or more. There is no particular limitation on the upper limit value, but 5,000,000 or less is practical. The mass average molecular weight of the above-mentioned phenoxy resin (C) is determined by polystyrene conversion by GPC [Gel Permeation Chromatography].

[0028] The glass transition temperature (Tg) of the above-mentioned phenoxy resin (C) is preferably less than 120°C, more preferably less than 100°C, and even more preferably less than 90°C. The lower limit is preferably 0°C or higher, and more preferably 10°C or higher. The glass transition temperature of the above-mentioned phenoxy resin (C) is the glass transition temperature measured by DSC at a heating rate of 0.1°C / min.

[0029] The composition for a transparent adhesive contains at least one kind of phenoxy resin as the phenoxy resin (C). In the present invention, the phenoxy resin (C) is one having an epoxy equivalent (the mass of the resin per equivalent of epoxy group) exceeding 500 g / eq. That is, even if it has the structure of a phenoxy resin, a resin having an epoxy equivalent of 500 g / eq or less is classified as the epoxy resin (A).

[0030] The phenoxy resin (C) can be obtained by the reaction of a bisphenol or biphenol compound with an epihalohydrin such as epichlorohydrin, or the reaction of a liquid epoxy resin with a bisphenol or biphenol compound. In any of the reactions, as the bisphenol or biphenol compound, a compound represented by the following general formula (A) is preferable.

[0031]

Chemical formula

[0032] In the general formula (A), L a represents a single bond or a divalent linking group, and R a1 and R a2 each independently represent a substituent. ma and na each independently represent an integer of 0 to 4.

[0033] In L a , the divalent linking group is preferably an alkylene group, a phenylene group, -O-, -S-, -SO-, -SO 2 -, or a group in which an alkylene group and a phenylene group are combined. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 3 carbon atoms, particularly preferably 1 or 2 carbon atoms, and most preferably 1 carbon atom. The alkylene group is preferably -C(R α )(R β )-, where R α and R β each independently represent a hydrogen atom, an alkyl group, or an aryl group. R α and R β may combine with each other to form a ring. R α and R β are preferably a hydrogen atom or an alkyl group (e.g., methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, hexyl, octyl, 2-ethylhexyl). Among them, the alkylene group is preferably -CH 2 -, -CH(CH 3 ), -C(CH 3 ) 2 -, more preferably -CH 2 -, -CH(CH 3 ), and still more preferably -CH 2 -.

[0034] The phenylene group preferably has 6 to 12 carbon atoms, more preferably 6 to 8 carbon atoms, and still more preferably 6 carbon atoms. Examples of the phenylene group include p-phenylene, m-phenylene, and o-phenylene, with p-phenylene and m-phenylene being preferred. As the group formed by combining an alkylene group and a phenylene group, an alkylene-phenylene-alkylene group is preferred, and -C(R α )(R β )-phenylene-C(R α )(R β )- is more preferred. R α and R β preferably form a 5- or 6-membered ring, more preferably a cyclopentane ring or a cyclohexane ring, and still more preferably a cyclohexane ring.

[0035] L a is a single bond or an alkylene group, -O-, -SO 2- is preferred, and an alkylene group is more preferred.

[0036] R a1 and R a2 are preferably an alkyl group, an aryl group, an alkoxy group, an alkylthio group, or a halogen atom, more preferably an alkyl group, an aryl group, or a halogen atom, and even more preferably an alkyl group.

[0037] ma and na are preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0038] The bisphenol or biphenol compound includes, for example, bisphenol A, bisphenol AD, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z, 4,4'-biphenol, 2,2'-dimethyl-4,4'-biphenol, 2,2',6,6'-tetramethyl-4,4'-biphenol, cardo skeleton type bisphenol, etc. Among them, bisphenol A, bisphenol AD, bisphenol C, bisphenol E, bisphenol F, 4,4'-biphenol are preferred, bisphenol A, bisphenol E, bisphenol F are more preferred, and bisphenol A is particularly preferred.

[0039] As the above liquid epoxy resin, a diglycidyl ether of an aliphatic diol compound is preferred, and a compound represented by the following general formula (B) is more preferred.

[0040]

Chemical formula

[0041] In the general formula (B), X represents an alkylene group, and nb represents an integer of 1 to 10.

[0042] The alkylene group preferably has 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, still more preferably 3 to 8 carbon atoms, particularly preferably 4 to 6 carbon atoms, and most preferably 6 carbon atoms. For example, ethylene, propylene, butylene, pentylene, hexylene, octylene can be mentioned, and ethylene, trimethylene, tetramethylene, pentamethylene, heptamethylene, hexamethylene, octamethylene are preferred.

[0043] nb is preferably 1 to 6, more preferably 1 to 3, and still more preferably 1.

[0044] Here, when nb is 2 to 10, X is preferably ethylene or propylene, and more preferably ethylene.

[0045] Examples of the aliphatic diol compound in the diglycidyl ether include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,7-pentanediol, 1,8-octanediol.

[0046] In the above reaction, the bisphenol or biphenol compound and the aliphatic diol compound may each be a phenoxy resin obtained by reacting alone or a phenoxy resin obtained by reacting a mixture of two or more. For example, the reaction of diglycidyl ether of 1,6-hexanediol with a mixture of bisphenol A and bisphenol F can be mentioned.

[0047] In the present invention, the phenoxy resin (C) is preferably a phenoxy resin obtained by reacting a liquid epoxy resin with a bisphenol or biphenol compound, and more preferably a phenoxy resin having a repeating unit represented by the following general formula (I).

[0048]

Chemical formula

[0049] In general formula (I), L a , R a1 , R a2 , ma and na are synonymous with L a , R a1 , R a2 , ma and na in general formula (A), and have the same preferred ranges. X and nb are synonymous with X and nb in general formula (B), and have the same preferred ranges.

[0050] Among these, in the present invention, a polymer of bisphenol A and diglycidyl ether of 1,6 - hexanediol is preferred. Focusing on the backbone of the phenoxy resin, in the present invention, bisphenol A - type phenoxy resin and bisphenol A·F - type copolymer - type phenoxy resin can be preferably used. Also, a low - elasticity high - heat - resistant type phenoxy resin can be preferably used.

[0051] The mass - average molecular weight of the phenoxy resin (C) is preferably 10,000 or more, and more preferably 10,000 to 100,000. Also, the amount of epoxy groups remaining slightly in the phenoxy resin (C) is preferably more than 5000 g / eq in terms of epoxy equivalent.

[0052] The phenoxy resin (C) may be synthesized by the above - mentioned method, or a commercially available product may be used. Examples of commercially available products include 1256 (bisphenol A - type phenoxy resin, manufactured by Mitsubishi Chemical Corporation), YP - 50 (bisphenol A - type phenoxy resin, manufactured by Shin - Nikka Epoxy Co., Ltd.), YP - 70 (bisphenol A / F - type phenoxy resin, manufactured by Shin - Nikka Epoxy Co., Ltd.), FX - 316 (bisphenol F - type phenoxy resin, manufactured by Shin - Nikka Epoxy Co., Ltd.), and FX - 280S (cardo - skeleton type phenoxy resin, manufactured by Shin - Nikka Epoxy Co., Ltd.), 4250 (bisphenol A - type / F - type phenoxy resin, manufactured by Mitsubishi Chemical Corporation), FX - 310 (low - elasticity high - heat - resistant type phenoxy resin, manufactured by Shin - Nikka Epoxy Co., Ltd.), etc. The proportion of the phenoxy resin (C) in the total of the respective contents of the epoxy resin (A) and the phenoxy resin (C) is 10 to 60% by mass, preferably 15 to 50% by mass, and more preferably 18 to 45% by mass.

[0053] (Inorganic filler (D)) As the inorganic filler (D), an inorganic filler usually used in a transparent adhesive composition can be used as long as the effects of the present invention are not impaired. Examples of the inorganic filler (D) include various inorganic powders such as ceramics such as silica, clay, gypsum, calcium carbonate, barium sulfate, alumina (aluminum oxide), beryllium oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, and boron nitride; metals such as aluminum, copper, silver, gold, nickel, chromium, lead, tin, zinc, palladium, and solder, or alloys; and carbons such as carbon nanotubes and graphene.

[0054] From the viewpoints of increasing the melt viscosity and enhancing the reliability (specifically, imparting a low coefficient of linear expansion, a low water absorption rate, etc.), the inorganic filler (D) is preferably a silica filler (D1). From the viewpoints of storage stability and transparency, the average particle diameter (d50) of the silica filler (D1) is preferably 0.01 to 1.0 μm, more preferably 0.01 to 0.8 μm, still more preferably 0.01 to 0.3 μm, and even more preferably 0.01 to 0.2 μm. From the viewpoints of storage stability and transparency, the particle diameter (d90) at a cumulative distribution frequency of 90% of the silica filler (D1) is preferably 0.05 to 2.0 μm, more preferably 0.05 to 1.0 μm, and even more preferably 0.1 to 1.0 μm. It is also preferable that the particle diameter (d90) at a cumulative distribution frequency of 90% of the silica filler (D1) is 1.0 μm or less. From the viewpoints of storage stability and transparency, the silica filler (D1) more preferably satisfies the following (3) and (4). (3) The average particle diameter (d50) is 0.01 to 0.3 μm (4) The particle diameter (d90) at a cumulative distribution frequency of 90% is 1.0 μm or less Here, the average particle size (d50) is the so-called median diameter, which means the particle size at which the cumulative distribution measured by the laser diffraction / scattering method reaches 50% cumulative when the total volume of the particles is taken as 100%. The particle size (d90) at a cumulative distribution frequency of 90% has the same meaning as the particle size (d90) at a cumulative distribution frequency of 90% described for the epoxy resin curing agent (B). When using an inorganic filler (D) other than the silica filler (D1), the range and preferred range of the average particle size (d50) and the particle size (d90) at a cumulative distribution frequency of 90% of the inorganic filler (D) can be the same as the range and preferred range described for the silica filler (D1).

[0055] The proportion of the content of the inorganic filler (D) in the total content (total solid content) of the epoxy resin (A), epoxy resin curing agent (B), phenoxy resin (C), and inorganic filler (D) is preferably 10 to 50% by mass, and more preferably 10 to 30% by mass. The proportion of the content of the silica filler (D1) in the total content of the epoxy resin (A), epoxy resin curing agent (B), phenoxy resin (C), and silica filler (D1) is preferably 10 to 50% by mass, and more preferably 10 to 30% by mass.

[0056] As a method of blending the inorganic filler (D) into resin components such as the epoxy resin (A), epoxy resin curing agent (B), and phenoxy resin (C), there are a method of directly blending a powdery inorganic filler with a silane coupling agent, phosphoric acid or a phosphate compound, and a surfactant as necessary (integral blend method), or a method of blending a slurry-like inorganic filler in which an inorganic filler treated with a surface treatment agent such as a silane coupling agent, phosphoric acid or a phosphate compound, and a surfactant is dispersed in an organic solvent can be used. Also, the method of treating the inorganic filler (D) with a silane coupling agent is not particularly limited, and examples include a wet method of mixing the inorganic filler (D) and the silane coupling agent in a solvent, a dry method of mixing the inorganic filler (D) and the silane coupling agent in a gas phase, and the above integral blend method.

[0057] The silane coupling agent is one in which at least one hydrolyzable group such as an alkoxy group or an aryloxy group is bonded to a silicon atom, and in addition to this, an alkyl group, an alkenyl group, or an aryl group may be bonded. The alkyl group is preferably one substituted with an amino group, an alkoxy group, an epoxy group, or a (meth)acryloyloxy group, and more preferably one substituted with an amino group (preferably a phenylamino group), an alkoxy group (preferably a glycidyloxy group), or a (meth)acryloyloxy group. Examples of the silane coupling agent include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and the like.

[0058]

[0059] ​​Examples of the shape of the inorganic filler (D) include flake, needle, filament, spherical, and scaly shapes, with spherical particles being preferred from the viewpoints of high filling and fluidity.

[0060] From the viewpoint of transparency, it is preferably in a form that does not use the silica filler (D1). When using the silica filler (D1), the average particle size (d50) of the silica filler (D1) is 0.01 to 0.3 μm, and the ratio of the content of the silica filler (D1) to the total content (total solid content) of the epoxy resin (A), epoxy resin curing agent (B), phenoxy resin (C), and silica filler (D1) is preferably 10 to 30% by mass. A preferred form of the composition for a transparent adhesive of the present invention contains a silica filler (D1), the silica filler (D1) satisfies the above (3) and (4), and the ratio of the content of the silica filler (D1) to the total content (total solid content) of the epoxy resin (A), epoxy resin curing agent (B), phenoxy resin (C), and silica filler (D1) is 10 to 50% by mass.

[0061] (Other components) In addition to the epoxy resin (A), epoxy resin curing agent (B), and phenoxy resin (C), the composition for a transparent adhesive of the present invention may contain other polymer compounds as long as the effects of the present invention are not impaired. Examples of the above polymer compounds include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, silicone rubber, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resins such as 6-nylon and 6,6-nylon, (meth)acrylic resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamideimide resin, fluororesin, etc. These polymer compounds may be used alone or in combination of two or more. Furthermore, the composition for a transparent adhesive of the present invention preferably contains an organic solvent (such as MEK). When the composition for a transparent adhesive of the present invention contains a solvent, the proportion of MEK in the solvent is preferably 40% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more. In addition, the composition for a transparent adhesive of the present invention may further contain an ion trap agent (ion scavenger), a curing catalyst, a viscosity modifier, an antioxidant, a flame retardant, a colorant, etc. For example, it can contain other additives of International Publication No. 2017 / 158994.

[0062] When the composition for a transparent adhesive of the present invention contains the epoxy resin (A), the epoxy resin curing agent (B), the phenoxy resin (C), and the inorganic filler (D), the total proportion of the respective contents of the inorganic filler (D) can be, for example, 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and can also be 90% by mass or more. Further, the above proportion may be 100% by mass, or may be 95% by mass or less. The composition for a transparent adhesive of the present invention can be suitably used to obtain the film-like transparent adhesive of the present invention. However, it is not limited to the film-like transparent adhesive, and can also be suitably used to obtain a liquid adhesive.

[0063] The composition for a transparent adhesive of the present invention can be obtained by mixing the above components at a temperature at which the epoxy resin (A) does not substantially thermoset. The order of mixing is not particularly limited. Resin components such as the epoxy resin (A) and the phenoxy resin (C) can be mixed with a solvent as needed, and then the inorganic filler (D) and the epoxy resin curing agent (B) can be mixed. In this case, the mixing in the presence of the epoxy resin curing agent (B) may be carried out at a temperature at which the epoxy resin (A) does not substantially thermoset, and the mixing of the resin components in the absence of the epoxy resin curing agent (B) may be carried out at a higher temperature.

[0064] From the perspective of suppressing the thermal curing of the epoxy resin (A), the composition for a transparent adhesive of the present invention is preferably stored under temperature conditions of 10°C or lower before use (before forming into a film-like transparent adhesive).

[0065] <<Film-like transparent adhesive>> The film-like transparent adhesive of the present invention is a film-like adhesive formed by forming a film of the composition for a transparent adhesive of the present invention, and contains the above-mentioned epoxy resin (A), epoxy resin curing agent (B), and phenoxy resin (C). The invention of the film-like transparent adhesive according to the present invention can be specified as follows.

[0066] A film-like transparent adhesive formed by forming a film of a composition for a transparent adhesive containing an epoxy resin (A), an epoxy resin curing agent (B), and a phenoxy resin (C), wherein the epoxy resin curing agent (B) satisfies the following (1) and (2). (1) It is in powder form and the particle size (d90) at a cumulative distribution frequency of 90% is 2.0 μm or less (2) The solubility in 100 g of methyl ethyl ketone at 25°C is 0.1 g or less

[0067] The film-like transparent adhesive of the present invention may contain the above-mentioned inorganic filler (D) in addition to the above epoxy resin (A), epoxy resin curing agent (B), and phenoxy resin (C), and may contain additives other than organic solvents among the additives described as other additives in the composition for a transparent adhesive of the present invention. Although the organic solvent is usually removed from the composition for a transparent adhesive by drying in the film-forming process of the composition for a transparent adhesive, it may be contained in the film-like transparent adhesive if it is about 0.1 to 1000 ppm. Film formation only needs to be able to make the composition for a transparent adhesive into a film shape, and is not particularly limited. It can be carried out by coating or the like described later. Here, in the present invention, "film" means a film with a thickness of 200 μm or less. The shape, size, etc. are not particularly limited and can be appropriately adjusted according to the usage mode.

[0068] The above film-shaped transparent adhesive has thermosetting properties, can be thermocompression bonded before thermosetting, and does not exhibit thermocompression bondability after thermosetting. In the present invention, the film-shaped transparent adhesive before thermosetting refers to the state before the epoxy resin (A) is thermoset. Specifically, the film-shaped transparent adhesive before thermosetting means a film-shaped transparent adhesive that has not been exposed to a temperature condition of 25°C or higher after the formation of the film-shaped transparent adhesive. On the other hand, the film-shaped transparent adhesive after thermosetting refers to the state in which the epoxy resin (A) has been thermoset. Specifically, it refers to a film-shaped transparent adhesive that has been exposed to a temperature condition equal to or higher than the thermosetting start temperature of the film-shaped transparent adhesive of the present invention. Note that the above description is for clarifying the characteristics of the film-shaped transparent adhesive of the present invention, and the film-shaped transparent adhesive of the present invention is not limited to one that has not been exposed to a temperature condition of 25°C or higher.

[0069] In the above film-shaped transparent adhesive, the epoxy resin curing agent (B) melts / react with the components in the adhesive and is incorporated into the resin component depending on the type of the epoxy resin curing agent (B) in the film-shaped transparent adhesive after thermocompression bonding and / or after thermosetting. However, it is preferable that at least a part thereof remains in a powder shape by recrystallization or the like.

[0070] The haze value of the film-shaped transparent adhesive of the present invention after thermosetting is not particularly limited, but is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less. The lower the haze value, the easier it is to visually recognize the alignment marks through the film-shaped transparent adhesive before and after thermosetting. The lower limit of the haze value is not particularly limited, but 1% or more is practical. The haze value is determined in accordance with JIS K 7136. The haze value can be controlled by the content of the epoxy resin curing agent (B) and / or the inorganic filler (D), and further by the types of the epoxy resin curing agent (B) and / or the inorganic filler (D), as well as the types and contents of coexisting compounds or resins such as the epoxy resin (A) and the phenoxy resin (C). The haze value tends to be lower as the average particle size of the epoxy resin curing agent (B) and / or the inorganic filler (D) is smaller or the content is less.

[0071] From the viewpoint of enhancing the die attachability, when the film-shaped transparent adhesive of the present invention is heated from 25°C at a heating rate of 5°C / min, it is preferably in the range of 100 to 10000 Pa·s, more preferably in the range of 200 to 10000 Pa·s, more preferably in the range of 500 to 10000 Pa·s, more preferably in the range of 1000 to 10000 Pa·s, more preferably in the range of 1500 to 10000 Pa·s, more preferably in the range of 8000 to 10000 Pa·s, and even more preferably in the range of 8000 to 9200 Pa·s at 120°C. When the melt viscosity at 120°C is within the above preferred range, the generation of voids can be more effectively reduced. The melt viscosity of the film-shaped transparent adhesive of the present invention can also be in the range of 300 to 4000 Pa·s or in the range of 1000 to 3500 Pa·s. The melt viscosity can be determined by the method described in the examples below. The melt viscosity can be controlled by the content of the epoxy resin curing agent (B) and / or the inorganic filler (D), and further by the types of the epoxy resin curing agent (B) and / or the inorganic filler (D), as well as the types and contents of coexisting compounds or resins such as the epoxy resin (A) and the phenoxy resin (C). The melt viscosity tends to increase as the average particle size of the epoxy resin curing agent (B) and / or the inorganic filler (D) is smaller and / or the content is larger.

[0072] The film-like transparent adhesive of the present invention preferably has a thickness of 1 to 100 μm. The thickness is more preferably 1 to 60 μm, still more preferably 3 to 30 μm, and particularly preferably 5 to 20 μm. The thickness of the film-like transparent adhesive can be measured by the contact linear gauge method (desktop contact type thickness measuring device).

[0073] There is no particular limitation on the method for preparing the film-like transparent adhesive of the present invention. For example, the composition (varnish) for the transparent adhesive of the present invention can be prepared, and this composition can be applied onto a release-treated base film and dried as necessary to form the film. The composition for the transparent adhesive usually contains an organic solvent. As the release-treated base film, any film that can function as a cover film for the obtained film-like transparent adhesive may be used, and known films can be appropriately adopted. For example, release-treated polypropylene (PP), release-treated polyethylene (PE), and release-treated polyethylene terephthalate (PET) can be mentioned. As the coating method, known methods can be appropriately adopted. For example, methods using a roll knife coater, a gravure coater, a die coater, a reverse coater, etc. can be mentioned. For drying, it is only necessary to remove the organic solvent from the composition for the transparent adhesive to form a film-like transparent adhesive without curing the epoxy resin (A). The drying temperature can be appropriately set according to the types of the epoxy resin (A), the phenoxy resin (C), and the epoxy resin curing agent (B) used. For example, it can be carried out by holding at a temperature of 80 to 150 °C for 1 to 20 minutes.

[0074] The film-like transparent adhesive of the present invention may be composed of the film-like transparent adhesive of the present invention alone, or may be in a form in which the above-mentioned release-treated base film is laminated on at least one surface of the film-like transparent adhesive. Further, the film-like transparent adhesive of the present invention may be in a form in which the film is cut into an appropriate size, or may be in a form in which the film is wound into a roll.

[0075] The film-shaped transparent adhesive of the present invention preferably has an arithmetic mean roughness Ra of 3.0 μm or less on at least one surface (i.e., at least one surface to be bonded to the adherend), and more preferably has an arithmetic mean roughness Ra of 3.0 μm or less on any surface to be bonded to the adherend. The above arithmetic mean roughness Ra is more preferably 2.0 μm or less, and even more preferably 1.5 μm or less. The lower limit is not particularly limited, but it is practical to be 0.1 μm or more.

[0076] The film-shaped transparent adhesive of the present invention is preferably stored under temperature conditions of 10°C or less before use (before curing) from the viewpoint of suppressing the curing of the epoxy resin (A).

[0077] The film-shaped transparent adhesive of the present invention has high storage stability and can maintain sufficiently high transparency even after thermosetting. The reason is not clear, but by using an epoxy resin, an epoxy resin curing agent, and a phenoxy resin, and using this epoxy resin curing agent as a powdery epoxy resin curing agent having specific particle size and solubility, before thermosetting, the compatibility between the epoxy resin curing agent and the epoxy resin and / or the phenoxy resin is reduced to enhance the storage stability, and it is considered possible to reduce the haze value after thermosetting.

[0078] <<Method for manufacturing a member with a transparent adhesive cured layer>> The method for manufacturing a member with a transparent adhesive cured layer of the present invention can be carried out by a usual method except that a transparent adhesive cured layer composed of a thermoset of the film-shaped transparent adhesive of the present invention is formed to obtain a member with a transparent adhesive cured layer. The transparent adhesive cured layer functions as, for example, a protective layer for the adherend. A preferred embodiment of the method for manufacturing a member with a transparent adhesive cured layer of the present invention includes thermocompression bonding the film-shaped transparent adhesive onto the adherend member and further thermosetting the film-shaped transparent adhesive. Examples of the adherend member include members used in optical devices such as optical lenses, optical fibers, optical waveguides, optical isolators, and semiconductor lasers, and members used in the manufacture of electronic components described below. Among these, the adherend member is preferably a transparent member such as a lens, glass (cover glass, glass substrate, glass wafer, etc.), or resin substrate. A plurality of film-like transparent adhesives may be used to form a transparent adhesive cured layer. The conditions for thermocompression bonding and thermosetting are the same as those for thermocompression bonding and thermosetting in the manufacturing method of electronic components described below. The transparent adhesive cured layer formed in this way exhibits the same haze value as the film-like transparent adhesive after thermosetting described above. The preferred range is also the same.

[0079] Another preferred embodiment of the method for manufacturing a member with a transparent adhesive cured layer according to the present invention is the method for manufacturing electronic components described below. The adherend member in the method for manufacturing a member with a transparent adhesive cured layer corresponds to the wafer in the method for manufacturing electronic components, and the member with a transparent adhesive cured layer corresponds to the electronic component.

[0080] <<Electronic Components and Their Manufacturing Methods>> In the electronic component of the present invention, at least one of the wafer chip (preferably a semiconductor chip) and the wiring substrate and between the wafer chips is adhered by the thermoset of the film-like transparent adhesive of the present invention. Normal wafer chips and wiring substrates can be used. The bonding conditions will be described in the explanation of the manufacturing method below. The electronic component is preferably a semiconductor package, capacitor, resistor, etc., and more preferably a semiconductor package. The manufacturing method of the electronic component of the present invention can be carried out in the same manner as the normal manufacturing method of electronic components, except that the film-like transparent adhesive of the present invention is used for the adhesion between at least one of the wafer chip and the wiring substrate and between the wafer chips.

[0081] A preferred embodiment of the manufacturing method of the electronic component of the present invention is as follows. That is, a method for manufacturing an electronic component, A first step of thermocompression bonding the film-like transparent adhesive of the present invention to one surface of a wafer and providing a dicing tape through the film-like transparent adhesive; A second step of obtaining a wafer chip with a transparent adhesive layer on the dicing tape by dicing the wafer and the film-like transparent adhesive integrally (simultaneously); A third step of removing the dicing tape from the transparent adhesive layer and thermocompression bonding the wafer chip with the transparent adhesive layer and other members through the transparent adhesive layer; A fourth step of thermosetting the transparent adhesive layer; A method for manufacturing an electronic component including the above steps. As the wafer, a normal wafer can be used, and examples include a semiconductor wafer, a glass wafer, and a ceramic wafer. Examples of the semiconductor wafer include a silicon wafer, a SiC wafer, a GaAs wafer, and a GaN wafer. A semiconductor circuit may or may not be formed on the surface of the wafer. It is preferable that at least one semiconductor circuit is formed on the surface of the wafer. The other member may be any member that constitutes an electronic component, and examples include a wiring board, another wafer, and bonding wires.

[0082] Another preferred embodiment of the method for manufacturing an electronic component of the present invention is as follows. That is, a method for manufacturing a semiconductor package, A first step of thermocompression bonding the film-like transparent adhesive of the present invention to the back surface of a semiconductor wafer having at least one semiconductor circuit formed on its surface and providing a dicing tape through the film-like transparent adhesive; A second step of obtaining a semiconductor chip with a transparent adhesive layer on the dicing tape by dicing the semiconductor wafer and the film-like transparent adhesive integrally (simultaneously); A third step of removing the dicing tape from the transparent adhesive layer and thermocompression bonding the semiconductor chip with the transparent adhesive layer and a wiring board through the transparent adhesive layer; A fourth step of thermosetting the transparent adhesive layer; A method for manufacturing a semiconductor package including the above steps.

[0083] Hereinafter, a preferred embodiment of the electronic component of the present invention and its manufacturing method will be described in detail by taking as an example the case of manufacturing a semiconductor package using a semiconductor wafer with reference to the drawings. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted. FIGS. 1 to 7 are schematic longitudinal sectional views showing a preferred embodiment of each step of a method for manufacturing a semiconductor package which is a preferred embodiment of the present invention. FIGS. 1 to 7 are schematic diagrams, and for convenience of explanation, the sizes and relative size relationships of each member such as a semiconductor wafer may be different from the actual ones. In a preferred embodiment of a method for manufacturing a semiconductor package which is a preferred embodiment of the present invention, first, as a first step, as shown in FIG. 1, on the back surface of a semiconductor wafer 1 having at least one semiconductor circuit formed on its surface (that is, the surface on which the semiconductor circuit of the semiconductor wafer 1 is not formed), the film-like transparent adhesive of the present invention is thermocompression bonded to provide an adhesive layer 2, and through this adhesive, a dicing tape 3 is provided. At this time, a product in which the adhesive layer 2 and the dicing tape 3 are integrated may be thermocompression bonded to the back surface of the semiconductor wafer 1 at once. The conditions for thermocompression bonding are carried out at a temperature at which the epoxy resin (A) does not substantially thermoset. For example, conditions of 70°C and a pressure of 0.3 MPa can be mentioned. As the adhesive layer 2, the film-like transparent adhesive of the present invention may be used alone in one layer or laminated in two or more layers. As a method for providing such an adhesive layer 2 on the back surface of the wafer 1, a method capable of laminating the film-like transparent adhesive on the back surface of the semiconductor wafer 1 can be appropriately adopted. When laminating two or more layers after laminating the film-like transparent adhesive on the back surface of the semiconductor wafer 1, methods such as sequentially laminating the film-like transparent adhesive until a desired thickness is obtained, or laminating the film-like transparent adhesive to a target thickness in advance and then laminating it to the back surface of the semiconductor wafer 1 can be mentioned. In addition, the apparatus used when providing such an adhesive layer 2 on the back surface of the semiconductor wafer 1 is not particularly limited, and for example, known apparatuses such as a roll laminator and a manual laminator can be appropriately used. The dicing tape 3 is not particularly limited, and a publicly known dicing tape can be used as appropriate.

[0084] Next, as a second step, as shown in FIG. 2, the semiconductor wafer 1 and the adhesive layer 2 are simultaneously diced to obtain a semiconductor chip 5 with a transparent adhesive layer including the semiconductor wafer 1 (semiconductor chip 4) and the transparent adhesive layer 2 on the dicing tape 3. The apparatus used for dicing is not particularly limited, and a publicly known dicing apparatus can be used as appropriate.

[0085] Next, as a third step, as shown in FIG. 3, the dicing tape 3 is removed from the adhesive layer 2, and the semiconductor chip 5 with a transparent adhesive layer and the wiring board 6 are thermocompression bonded via the transparent adhesive layer 2. In this way, the semiconductor chip 5 with a transparent adhesive layer is mounted on the wiring board 6. As the wiring board 6, a board having a semiconductor circuit formed on its surface can be used as appropriate. For example, a printed circuit board (PCB), various lead frames, and a board having electronic components such as resistor elements and capacitors mounted on the board surface can be mentioned. As a method of removing (peeling off) the dicing tape 3 from the transparent adhesive layer (a method of picking up a semiconductor chip with an adhesive layer), a picking-up method using a normal jig can be adopted. Specifically, a method of peeling off the dicing tape 3 with a jig such as a needle or a slider can be mentioned. The method of mounting the semiconductor chip 5 with a transparent adhesive layer on the wiring board 6 is not particularly limited, and a conventional method capable of adhering the semiconductor chip 5 with a transparent adhesive layer to the wiring board 6 or an electronic component mounted on the surface of the wiring board 6 using the transparent adhesive layer 2 can be adopted as appropriate. Examples of such mounting methods include a method using a mounting technique using a flip chip bonder having a heating function from above, a method using a die bonder having a heating function only from below, and a method using a laminator, and other conventionally known heating and pressurizing methods. The conditions for mounting (thermocompression bonding) are performed under conditions where the epoxy resin (A) does not substantially thermoset. For example, conditions of 120 ° C, a pressure of 0.1 MPa, and 1.0 second can be mentioned. Thus, by mounting the semiconductor chip 5 with the transparent adhesive layer on the wiring board 6 through the transparent adhesive layer 2 made of the film-like transparent adhesive of the present invention, the film-like transparent adhesive can follow the uneven portions on the wiring board 5 caused by the electronic components, so that the semiconductor chip 4 and the wiring board 6 can be closely adhered and fixed.

[0086] Next, as a fourth step, the transparent adhesive layer 2 (the film-like transparent adhesive of the present invention) is thermally cured to form a thermoset. The temperature of the thermal curing is not particularly limited as long as it is equal to or higher than the thermal curing start temperature of the film-like transparent adhesive of the present invention, and it varies depending on the types of the epoxy resin (A), the phenoxy resin (C), and the epoxy resin curing agent (B) used, and it cannot be generally stated. However, for example, 100 to 180 °C is preferable, and from the viewpoint that curing can be achieved in a shorter time at a higher temperature, 140 to 180 °C is more preferable. If the temperature is lower than the thermal curing start temperature, the thermal curing does not proceed sufficiently, and the strength of the adhesive layer 2 tends to decrease. On the other hand, if it exceeds the above upper limit, the epoxy resin, curing agent, additives, etc. in the film-like transparent adhesive tend to volatilize and foam during the curing process. Also, the curing treatment time is preferably, for example, 10 to 120 minutes.

[0087] Next, in the method for manufacturing a semiconductor package which is a preferred embodiment of the present invention, as shown in FIG. 4, it is preferable to connect the wiring board 6 and the semiconductor chip 5 with the adhesive layer via the bonding wire 7. Such a connection method is not particularly limited, and a conventionally known method, for example, a wire bonding method, a TAB (Tape Automated Bonding) method, etc. can be appropriately adopted.

[0088] Also, another semiconductor chip 4 can be thermocompression bonded and thermally cured on the surface of the mounted semiconductor chip 4, and then connected to the wiring board 6 again by the wire bonding method, so that a plurality of them can be stacked. For example, as shown in FIG. 5, there is a method of stacking the semiconductor chips with a shift, or as shown in FIG. 6, there is a method of stacking while embedding the bonding wire 7 by making the adhesive layer 2 of the second layer and subsequent layers thicker.

[0089] In the method for manufacturing a semiconductor package which is a preferred embodiment of the present invention, as shown in FIG. 7, it is preferable to seal the wiring board 6 and the semiconductor chip 5 with an adhesive layer by a sealing resin 8, and in this way, the semiconductor package 9 can be obtained. The sealing resin 8 is not particularly limited, and an appropriately known sealing resin that can be used in the manufacture of semiconductor packages can be used. Also, the sealing method using the sealing resin 8 is not particularly limited, and an appropriately known method can be adopted.

Example

[0090] Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. Also, room temperature means 25°C, MEK is methyl ethyl ketone, and PET is polyethylene terephthalate. Details of the pulverization treatment of the epoxy resin curing agent used in each example and comparative example, and the method for measuring the particle size distribution before and after the pulverization treatment will be described separately later.

[0091] (Example 1) 56 parts by mass of a triphenylmethane type epoxy resin (trade name: EPPN-501H, mass average molecular weight: 1000, softening point: 55°C, semi-solid, epoxy equivalent: 167 g / eq, manufactured by Nippon Kayaku Co., Ltd.), 49 parts by mass of a bisphenol A type epoxy resin (trade name: YD-128, mass average molecular weight: 400, softening point: 25°C or lower, liquid, epoxy equivalent: 190 g / eq, manufactured by Shin-Nichi Kasei Co., Ltd.), 30 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, mass average molecular weight: 70000, Tg: 84°C, elastic modulus at room temperature (25°C): 1700 MPa, manufactured by Shin-Nichi Kasei Co., Ltd.) and 67 parts by mass of MEK were heated and stirred at a temperature of 110°C for 2 hours in a 1000 ml separable flask to obtain a resin varnish. Next, this resin varnish was transferred to an 800-ml planetary mixer, and 53 parts by mass of a silica slurry filler (trade name: YA010C-MFN, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.01 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.1 μm, solid content 30% (organic solvent: MEK)) (16 parts by mass of silica filler) was added, and 8.5 parts by mass of a crushed imidazole compound (trade name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd., average particle size (d50): 0.15 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.39 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK) was added. After stirring and mixing at room temperature for 1 hour, vacuum degassing was performed to obtain a mixed varnish. Next, the obtained mixed varnish was applied onto a release-treated PET film (release film) with a thickness of 38 μm, and heat-dried at 130°C for 10 minutes to form a film-like transparent adhesive layer having a length of 300 mm, a width of 200 mm, and a thickness of 50 μm, thereby obtaining a film-like transparent adhesive with a release film. The obtained film-like transparent adhesive with a release film was stored at 10°C or lower. After the drying, the epoxy resin was not cured (hereinafter, unless otherwise specified, the same applies to other examples and comparative examples).

[0092] (Example 2) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the amount of the silica slurry filler (trade name: YA010C-MFN, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.01 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.1 μm, solid content 30% (organic solvent: MEK)) used was 203 parts by mass (61 parts by mass of silica filler).

[0093] (Example 3) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the amount of the silica slurry filler (trade name: YA010C-MFN, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.01 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.1 μm, solid content 30% (organic solvent: MEK)) used was 477 parts by mass (143 parts by mass of silica filler).

[0094] (Example 4) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the inorganic filler was replaced with 27 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (16 parts by mass of silica filler).

[0095] (Example 5) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the inorganic filler was replaced with 102 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (61 parts by mass of silica filler).

[0096] (Example 6) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the inorganic filler was replaced with 238 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (143 parts by mass of silica filler).

[0097] (Example 7) A film-like transparent adhesive with a release film was produced in the same manner as in Example 1, except that the inorganic filler was replaced with 32 parts by mass of a silica slurry filler (trade name: SIRMEK50WT%-M01, manufactured by CIK Nanotech Co., Ltd., average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 1.0 μm, solid content 50% (organic solvent: MEK)) (16 parts by mass of silica filler).

[0098] (Example 8) A film-shaped transparent adhesive with a release film was prepared in the same manner as in Example 1, except that the inorganic filler was replaced with 122 parts by mass of a silica slurry filler (trade name: SIRMEK50WT%-M01, manufactured by CIK Nanotech Co., Ltd., average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 1.0 μm, solid content 50% (organic solvent: MEK)) (61 parts by mass of silica filler).

[0099] (Example 9) A film-shaped transparent adhesive with a release film was prepared in the same manner as in Example 1, except that the inorganic filler was replaced with 286 parts by mass of a silica slurry filler (trade name: SIRMEK50WT%-M01, manufactured by CIK Nanotech Co., Ltd., average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 1.0 μm, solid content 50% (organic solvent: MEK)) (143 parts by mass of silica filler).

[0100] (Example 10) A film-shaped transparent adhesive with a release film was prepared in the same manner as in Example 9, except that the epoxy resin curing agent was replaced with 7.5 parts by mass of crushed dicyandiamide (trade name: DICY7, manufactured by Mitsubishi Chemical Corporation, average particle size (d50): 0.5 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.95 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK).

[0101] (Example 11) A film-shaped transparent adhesive with a release film was prepared in the same manner as in Example 9, except that the epoxy resin curing agent was replaced with 28.5 parts by mass of crushed organic acid hydrazide (trade name: N14, manufactured by Mitsubishi Chemical Corporation, average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 2.0 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK).

[0102] (Example 12) A film-like transparent pressure-sensitive adhesive with a release film was produced in the same manner as in Example 10, except that a silica slurry filler (trade name: SIRMEK50WT%-M01, manufactured by CIK Nanotech Co., Ltd., average particle diameter (d50): 0.8 μm, particle diameter (d90) at a cumulative distribution frequency of 90%: 1.0 μm, solid content 50% (organic solvent: MEK)) was not used.

[0103] (Comparative Example 1) A film-like transparent pressure-sensitive adhesive with a release film was produced in the same manner as in Example 3, except that 8.5 parts by mass of a crushed untreated imidazole compound (trade name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd., average particle diameter (d50): 1.9 μm, particle diameter (d90) at a cumulative distribution frequency of 90%: 3.9 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK) was used instead of the epoxy resin curing agent.

[0104] (Comparative Example 2) A film-like transparent pressure-sensitive adhesive with a release film was produced in the same manner as in Comparative Example 1, except that the amount of a silica slurry filler (trade name: YA010C-MFN, manufactured by Admatechs Co., Ltd., average particle diameter (d50): 0.01 μm, particle diameter (d90) at a cumulative distribution frequency of 90%: 0.1 μm, solid content 30% (organic solvent: MEK)) was 713 parts by mass (including 214 parts by mass of silica filler).

[0105] (Comparative Example 3) A film-like transparent pressure-sensitive adhesive with a release film was produced in the same manner as in Comparative Example 1, except that the inorganic filler was replaced with 238 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle diameter (d50): 0.1 μm, particle diameter (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (including 143 parts by mass of silica filler).

[0106] (Comparative Example 4) A film-like transparent adhesive with a release film was produced in the same manner as in Comparative Example 1, except that the inorganic filler was replaced with 357 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (214 parts by mass of silica filler).

[0107] (Comparative Example 5) A film-like transparent adhesive with a release film was produced in the same manner as in Comparative Example 3, except that the epoxy resin curing agent was replaced with 7.5 parts by mass of uncrushed dicyandiamide (trade name: DICY7, manufactured by Mitsubishi Chemical Corporation, average particle size (d50): 7.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 15.0 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK).

[0108] (Comparative Example 6) A film-like transparent adhesive with a release film was produced in the same manner as in Comparative Example 1, except that the inorganic filler was replaced with 272 parts by mass of a silica slurry filler (trade name: YC100C-MLA, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.1 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.3 μm, solid content 60% (organic solvent: MEK)) (163 parts by mass of silica filler), and the epoxy resin curing agent was replaced with 28.5 parts by mass of uncrushed organic acid hydrazide (trade name: N14, manufactured by Mitsubishi Chemical Corporation, average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 5.3 μm, solubility in MEK at 25°C less than 0.01 g / 100 g-MEK).

[0109] (Comparative Example 7) A film-like transparent adhesive with a release film was produced in the same manner as in Comparative Example 1, except that the inorganic filler was replaced with 204 parts by mass of a silica slurry filler (trade name: SC2050-MNU, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.8 μm, particle size (d90) at a cumulative distribution frequency of 90%: 5.0 μm, solid content 70% (organic solvent: MEK)) (143 parts by mass of silica filler).

[0110] (Comparative Example 8) A film-like transparent adhesive with a release film was produced in the same manner as in Example 12, except that 8.5 parts by mass of the epoxy resin curing agent was replaced with an uncrushed imidazole compound (trade name: 2MZ-H, manufactured by Shikoku Kasei Co., Ltd., average particle size (d50): 3.2 μm, particle size (d90) at a cumulative distribution frequency of 90%: 8.2 μm, solubility in MEK at 25°C: 5.3 g / 100 g-MEK).

[0111] (Comparative Example 9) A film-like transparent adhesive with a release film was produced in the same manner as in Example 12, except that 8.5 parts by mass of the epoxy resin curing agent was replaced with a crushed imidazole compound (trade name: 2MZ-H, manufactured by Shikoku Kasei Co., Ltd., average particle size (d50): 0.15 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.8 μm, solubility in MEK at 25°C: 5.3 g / 100 g-MEK).

[0112] (Comparative Example 10) A film-like transparent adhesive with a release film was produced in the same manner as in Example 12, except that 8.5 parts by mass of the epoxy resin curing agent was replaced with an uncrushed imidazole compound (trade name: 2E4MZ, manufactured by Shikoku Kasei Co., Ltd., average particle size (d50): 2.2 μm, particle size (d90) at a cumulative distribution frequency of 90%: 5.4 μm, solubility in MEK at 25°C: 10 g or more / 100 g-MEK).

[0113] (Comparative Example 11) A film-like transparent adhesive with a release film was produced in the same manner as in Example 12, except that 8.5 parts by mass of the epoxy resin curing agent was replaced with a crushed imidazole compound (trade name: 2E4MZ, manufactured by Shikoku Kasei Co., Ltd., average particle size (d50): 0.55 μm, particle size (d90) at a cumulative distribution frequency of 90%: 0.9 μm, solubility in MEK at 25°C: 10 g or more / 100 g-MEK).

[0114] (Comparative Example 12) A film-like transparent adhesive with a release film was prepared in the same manner as in Comparative Example 1, except that silica slurry filler (product name: YA010C-MFN, manufactured by Admatechs Co., Ltd., average particle size (d50): 0.01 μm, particle size at cumulative distribution frequency 90% (d90): 0.1 μm, solid content 30% (organic solvent: MEK)) was not used.

[0115] The particle size of the epoxy resin curing agent used in each of the Examples and Comparative Examples was adjusted by the following grinding treatment. (Crushing of epoxy resin hardener) Various epoxy resin hardeners were treated in a dry grinder (product name: Dry-Burst Parallel DB-180WP, manufactured by Sugino Machine) at a rotation speed of 5000 rev / min for 3 hours.

[0116] The particle size distribution of the epoxy resin curing agent used in each of the Examples and Comparative Examples before and after the grinding treatment was measured as follows. (Measurement of particle size distribution of hardener before and after crushing process) 0.1g of epoxy resin hardener and 9.9g of isopropyl alcohol (IPA) were weighed before and after the crushing treatment, and the mixture was subjected to ultrasonic dispersion treatment for 5 minutes to prepare a measurement sample. The average particle size (d50) and the particle size at 90% cumulative distribution frequency (d90) were calculated from the cumulative curve of the particle size volume fraction of the particle size distribution measured by the laser diffraction / scattering method (model: LMS-2000e, manufactured by Seishin Enterprise Co., Ltd.) for this measurement sample. The results are shown in Table 1.

[0117] The solubility of the epoxy resin curing agent used in each of the Examples and Comparative Examples in 100 g of a solvent (MEK) was determined as follows. (Solubility of epoxy resin hardener (g / 100g-MEK)) 10 g of each epoxy resin hardener was weighed out into a beaker, 100 g of MEK was added, and the mixture was stirred for a specified time (60 minutes) with a magnetic stirrer at room temperature (25°C). After stirring, the insoluble epoxy resin hardener was filtered out, the amount of epoxy resin hardener in the insoluble matter (Xg) was measured, and the solubility was calculated as (10-X)g.

[0118]

Table 1

[0119] The particle size distributions of the inorganic fillers used in each example and comparative example were measured by the same method as that described above (measurement of the particle size distribution of the curing agent before and after crushing treatment).

[0120] In each example and comparative example, haze measurement, melt viscosity measurement, die attachability evaluation, visibility evaluation, and storage stability evaluation were carried out by the methods shown below, respectively. The results are shown in Tables 2 and 3.

[0121] <Haze measurement> From the film-like transparent adhesive with a release film obtained in each example and comparative example, a square with a size of 5.0 cm in length × 5.0 cm in width was cut out, and the film-like transparent adhesive was thermally cured by heating at 180 °C for 1 hour. The haze of the thermally cured film-like transparent adhesive was measured with a haze meter (model: HZ-V3, manufactured by Suga Test Instruments Co., Ltd.) using a measurement aperture of 20 mmφ and light source D65 light.

[0122] <Measurement of melt viscosity> From the film-like transparent adhesive with a release film obtained in each example and comparative example, a square with a size of 5.0 cm in length × 5.0 cm in width was cut out, and the samples cut out in the state where the release film was peeled off were laminated and bonded together with a hand roller on a stage at 70 °C to obtain a test piece with a thickness of about 1.0 mm. For this test piece, using a rheometer (RS6000, manufactured by Haake), the change in viscous resistance in the temperature range of 20 to 250 °C and a heating rate of 5 °C / min was measured. From the obtained temperature-viscous resistance curve, the melt viscosity (Pa·s) at 120 °C was calculated respectively.

[0123] <Die attachability evaluation> The film-like transparent adhesive with release film obtained in each Example and Comparative Example was first adhered to one side of a dummy silicon wafer (8 inch size, thickness 100 μm) using a manual laminator (product name: FM-114, manufactured by Technovision) at a temperature of 70° C. and a pressure of 0.3 MPa. After that, the release film was peeled off from the film-like transparent adhesive, and then a dicing tape (product name: K-13, manufactured by Furukawa Electric Co., Ltd.) and a dicing frame (product name: DTF2-8-1H001, manufactured by DISCO) were adhered to the surface of the film-like transparent adhesive opposite the dummy silicon wafer using the same manual laminator at room temperature and a pressure of 0.3 MPa. Next, dicing was performed from the dummy silicon wafer side to a size of 10 mm x 10 mm using a dicing device (product name: DFD-6340, manufactured by DISCO) equipped with a two-axis dicing blade (Z1: NBC-ZH2050 (27HEDD), manufactured by DISCO / Z2: NBC-ZH127F-SE (BC), manufactured by DISCO), to obtain a dummy chip with a film-like transparent adhesive. Next, the dummy chip with the film-like transparent adhesive was picked up from the dicing tape using a die bonder (product name: DB-800, manufactured by Hitachi High-Technologies Corporation), and the film-like transparent adhesive side of the dummy chip with the film-like transparent adhesive was bonded to the mounting surface side of a lead frame substrate (42Alloy type, manufactured by Toppan Printing Co., Ltd.) by thermocompression bonding under conditions of 120°C, pressure of 0.1 MPa (load of 400 gf), and time of 1.0 second. Here, the mounting surface of the lead frame substrate is a metal surface with slight surface roughness. The dummy chip with the film-like transparent adhesive thermocompression bonded onto the substrate was observed for the presence or absence of voids at the interface between the film-like transparent adhesive and the lead frame substrate mounting surface using an ultrasonic flaw detector (SAT) (Hitachi Power Solutions, FS300III), and the die attachment property was evaluated based on the following evaluation criteria. In this test, an evaluation rank of "A" is the pass level. Evaluation Criteria A: No voids were observed in any of the 24 mounted dummy chips. B: Among one or more and three or fewer of the 24 implemented dummy chips, voids are observed. C: Among four or more of the 24 implemented dummy chips, voids are observed.

[0124] <Visual recognition evaluation> Visual recognition was evaluated as an index of transparency. On the surface of a silicon chip (size: 10 × 10 mm, thickness: 350 μm) with an alignment mark of L mark (100 μm on each side), the film-shaped transparent adhesive with a release film obtained in each example and comparative example was bonded with a hand roller on a stage at 70°C, and the film-shaped transparent adhesive was thermally cured by heating at 180°C for 1 hour. The release film was peeled off, and a dicing tape (product name: K-13, manufactured by Furukawa Electric Co., Ltd.) and a dicing frame (product name: DTF2-8-1H001, manufactured by DISCO) were bonded to the surface of the silicon chip on the side opposite to the surface to which the film-shaped transparent adhesive was attached. Next, an alignment mark on the chip surface was recognized through the thermally cured film-shaped transparent adhesive by a die bonder (product name: DB-800, manufactured by Hitachi High-Technologies Corporation), and a visual recognition evaluation was performed based on the following evaluation criteria. The evaluation was performed by adjusting the luminance of the illumination provided by the die bonder between 30% and 70%. In this test, the evaluation rank "A" is the passing level. Evaluation Criteria AA: Recognizable by the die bonder in the range of luminance: 30% to 70% in the 24 tested semiconductor chips A: Unrecognizable by the die bonder in the range of luminance: 30% or more and less than 50%, but recognizable in the range of luminance: 50% to 70% in the 24 tested semiconductor chips B: One or more and three or fewer recognition errors occur in the range of luminance: 50% to 70% by the die bonder among the 24 tested silicon chips C: Four or more recognition errors occur in the range of luminance: 50% to 70% by the die bonder among the 24 tested silicon chips Here, 100% brightness refers to the maximum brightness of the illumination provided by the above die bonder. The higher the brightness, the more the influence on the recognition of alignment marks caused by regions with refractive indices different from the resin component in the film-like transparent adhesive (such as epoxy resin hardeners, inorganic fillers, etc.) can be reduced. However, when the brightness exceeds 70%, conversely, it becomes difficult to recognize the alignment marks themselves. In the above test, the recognizability of alignment marks was evaluated in the range of 30% to 70% brightness. For a film-like transparent adhesive with AA evaluation, the alignment marks can be recognized regardless of which die bonder is used (for example, even if the above die bonder is worn out and the brightness has decreased). Also, even if the alignment marks cannot be recognized in the range of more than 30% and less than 50%, if the alignment marks can be recognized in the range of 50% to 70% brightness (A evaluation), by using a normal device (not an extremely worn-out die bonder with extremely low brightness) and adjusting the brightness as necessary, the alignment marks can be sufficiently recognized.

[0125] <Storage Stability Test> The test pieces, which were 5.0 cm long × 5.0 cm wide × approximately 1.0 mm thick and were produced in the above melt viscosity measurement, were stored for 30 days in an environment of temperature: 25°C ± 2°C, relative humidity: 60% RH ± 5%. For the test pieces after this storage, using a rheometer (RS6000, manufactured by Haake), the change in viscous resistance was measured in the temperature range of 20 to 250°C with a heating rate of 5°C / min. From the obtained temperature-viscous resistance curve, the melt viscosity (Pa·s) at 120°C was calculated respectively. The melt viscosity thus obtained was taken as the melt viscosity of the test pieces after storage. Furthermore, the melt viscosity of the test pieces measured in the above melt viscosity measurement was taken as the melt viscosity of the test pieces before storage. The melt viscosity of the test pieces before storage was designated as "V A " (initial value), the melt viscosity of the test pieces after storage was designated as "V B ", and the change rate of V A with respect to V B (=(V B - V A ) / V A × 100 (%)) was determined, and the storage stability was evaluated based on the following evaluation criteria. In this test, the evaluation rank "A" is the passing level. Evaluation Criteria A: The change rate of the melt viscosity of the test piece after storage with respect to the initial value exceeds -1% and is less than +1%. B: The change rate of the melt viscosity of the test piece after storage with respect to the initial value exceeds -5% and is less than or equal to -1%, or is greater than or equal to +1% and less than +5%. C: The change rate of the melt viscosity of the test piece after storage with respect to the initial value is less than or equal to -5% or greater than or equal to +5%.

[0126]

Table 2

[0127]

Table 3

[0128] <Note to the table> The blank in the column of the adhesive layer means that the component is not contained. Liquid bisphenol A type epoxy resin: Bisphenol A type epoxy resin Bisphenol A type phenoxy resin: Bisphenol A type phenoxy resin

[0129] From Tables 1 and 2 above, the following can be understood. All of the film-like transparent adhesives obtained using the transparent adhesive composition containing an epoxy resin curing agent that does not meet the requirements of the present invention in Comparative Examples 1 to 12 failed at least one of the visibility evaluation and the storage stability evaluation. Furthermore, Comparative Examples 2 and 4 also failed the die attachability evaluation. In contrast, the film-like transparent adhesives obtained using the adhesive composition of Examples 1 to 12 that meet the requirements of the present invention were excellent in visibility and storage stability, and also excellent in die attachability. In particular, even when a large amount of epoxy resin curing agent was added to the epoxy resin (for example, when the epoxy resin curing agent was contained in an amount of 2.0 parts by mass or more with respect to 100 parts by mass of the epoxy resin), the visibility was excellent.

[0130] Although the present invention has been described with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified, and we believe that it should be broadly construed without departing from the spirit and scope of the invention shown in the appended claims.

[0131] This application claims priority based on Japanese Patent Application No. 2020-163561, which was filed in Japan on September 29, 2020, and the contents thereof are incorporated herein by reference as part of the description of this specification.

Explanation of Reference Numerals

[0132] 1 Semiconductor wafer 2 Adhesive layer (film-like transparent adhesive) 3 Dicing tape 4 Semiconductor chip 5 Semiconductor chip with film-like transparent adhesive 6 Wiring board 7 Bonding wire 8 Encapsulating resin 9 Semiconductor package

Claims

1. A composition for a transparent adhesive containing an epoxy resin (A), an epoxy resin curing agent (B), and a phenoxy resin (C), wherein the epoxy resin (A) is contained in an amount of 30 to 80 parts by mass per 100 parts by mass of the total content of components other than the solvent, the epoxy resin curing agent (B) is contained in an amount of 2 to 50 parts by mass per 100 parts by mass of the epoxy resin (A), the proportion of the phenoxy resin (C) in the total of the epoxy resin (A) and the phenoxy resin (C) is 10 to 60% by mass, and the epoxy resin curing agent (B) is a latent curing agent, and the composition for a transparent adhesive satisfies the following (1) and (2). (1) It is in powder form and the particle size (d90) at a cumulative distribution frequency of 90% is 2.0 μm or less (2) The solubility in 100 g of methyl ethyl ketone at 25°C is 0.1 g or less

2. Containing a silica filler (D1), the silica filler (D1) satisfies the following (3) and (4), and the proportion of the content of the silica filler (D1) in the total content of each of the epoxy resin (A), the epoxy resin curing agent (B), the phenoxy resin (C), and the silica filler (D1) is 10 to 50% by mass. The composition for a transparent adhesive according to Claim 1. (3) The average particle size (d50) is 0.01 to 0.3 μm (4) The particle size (d90) at a cumulative distribution frequency of 90% is 1.0 μm or less

3. The composition for a transparent adhesive according to Claim 1 or 2, wherein the epoxy resin curing agent (B) contains a dicyandiamide compound, an imidazole compound, or a hydrazide compound.

4. The composition for a transparent adhesive according to any one of Claims 1 to 3, wherein the content of the epoxy resin curing agent (B) per 100 parts by mass of the epoxy resin (A) is 4 to 20 parts by mass.

5. A film-like transparent adhesive formed by forming a film of the composition for a transparent adhesive according to any one of Claims 1 to 4.

6. The film-like transparent adhesive according to Claim 5, wherein the haze value after thermosetting of the film-like transparent adhesive is 50% or less.

7. The film-like transparent adhesive according to Claim 5 or 6, wherein when the film-like transparent adhesive before thermosetting is heated at a heating rate of 5°C / min from 25°C, the melt viscosity at 120°C reaches a range of 100 to 10,000 Pa·s.

8. The film-like transparent adhesive according to any one of Claims 5 to 7, having a thickness of 1 to 100 μm.

9. A method for manufacturing a member with a transparent adhesive cured layer, comprising thermocompression bonding the film-like transparent adhesive according to any one of claims 5 to 8 onto a adherend member and thermosetting the film-like transparent adhesive.

10. A method for manufacturing an electronic component, comprising: a first step of thermocompression bonding the film-like transparent adhesive according to any one of claims 5 to 8 onto one surface of a wafer and providing a dicing tape through the film-like transparent adhesive; a second step of obtaining a wafer chip with a transparent adhesive layer on the dicing tape by dicing the wafer and the film-like transparent adhesive integrally; a third step of removing the dicing tape from the transparent adhesive layer and thermocompression bonding the wafer chip with the transparent adhesive layer and another member through the transparent adhesive layer; a fourth step of thermosetting the transparent adhesive layer; A method for manufacturing an electronic component, comprising the above steps.

11. An electronic component, wherein between a wafer chip and a wiring board and / or between wafer chips is adhered by a thermoset of the film-like transparent adhesive according to any one of claims 5 to 8.

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