Photosensitive resin composition and semiconductor device

Abstract

To provide a photosensitive resin composition which has good adhesion to gallium nitride and is also excellent in adhesive strength, and a semiconductor device having a cured film of the photosensitive resin composition as a protective film.SOLUTION: A photosensitive resin composition is used as a protective film of a gallium nitride semiconductor, and contains a thermosetting resin, a photosensitive agent, and a first coupling agent having an acid anhydride group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition and a semiconductor device. More specifically, the present invention relates to a photosensitive resin composition for producing a protective film or encapsulant for a gallium nitride semiconductor, and a semiconductor device produced using the photosensitive resin composition. [Background technology]

[0002] Resin materials are used in semiconductor devices for many purposes, such as protection, interlayer insulation, planarization, and adhesion. A technique for forming patterns by imparting photosensitivity and optical transparency to resin materials is also known. This allows the formation of desired patterns with high precision. For example, Patent Document 1 describes a photosensitive resin composition containing a cyclic olefin resin having a protic polar group, an unsaturated group-containing compound, and a radical-generating photopolymerization initiator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-025892 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the photosensitive resin composition described in Patent Document 1 has the problem that it has low adhesion to inorganic materials and the adhesion strength is not sufficient.

[0005] The present invention aims to provide a photosensitive resin composition that has good adhesion to gallium nitride and excellent adhesive strength, and a semiconductor device that includes a cured film of the photosensitive resin composition as a protective film. [Means for solving the problem]

[0006] The present inventors have discovered that by using a thermosetting resin in combination with a specific coupling agent, a photosensitive resin composition can be obtained that is capable of forming a cured film that has good adhesion to a gallium nitride semiconductor, and have arrived at the present invention.

[0007] According to the present invention, A photosensitive resin composition used as a protective film for a gallium nitride semiconductor, comprising: a thermosetting resin; A photosensitizer and a first coupling agent having an acid anhydride group; fruit, the thermosetting resin includes a resin containing a structural unit derived from a cyclic olefin, The resin containing a structural unit derived from a cyclic olefin is a resin containing a structural unit represented by formula (A), a structural unit represented by formula (1), and a structural unit represented by formula (4), [ka] In formula (A), R 1 、R 2 、R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms, 1 is 0, 1 or 2, [ka] In formula (1), R 11 is a group containing a terminal reactive unsaturated double bond, and R 21 is a hydrogen atom or an organic group having 1 to 3 carbon atoms, [ka] In equation (4), R 22 is a hydrogen atom or an organic group having 1 to 3 carbon atoms, Photosensitive resin composition is provided.

[0008] Further, according to the present invention, a gallium nitride semiconductor disposed on the substrate; a protective film that protects at least a portion of the substrate and the gallium nitride semiconductor; A semiconductor device comprising: The present invention provides a semiconductor device, wherein the protective film is made of a cured product of the photosensitive resin composition according to any one of claims 1 to 10. [Effects of the Invention]

[0009] According to the present invention, there are provided a photosensitive resin composition that has good adhesion to gallium nitride and excellent adhesive strength, and a semiconductor device that includes a cured film of the photosensitive resin composition as a protective film. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described. In this specification, the expression "a to b" in the description of a range of values ​​means not less than a and not more than b, unless otherwise specified. For example, "5 to 90%" means "not less than 5% and not more than 90%."

[0011] In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, it encompasses both groups having no substituents and groups having a substituent. For example, the term "alkyl group" encompasses not only alkyl groups having no substituents (unsubstituted alkyl groups) but also alkyl groups having a substituent (substituted alkyl groups).

[0012] In this specification, the term "(meth)acrylic" refers to a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." In particular, in this specification, the term "(meth)acryloyl group" refers to a concept that encompasses both an acryloyl group represented by -C(=O)-CH=CH2 and a methacryloyl group represented by -C(=O)-C(CH3)=CH2.

[0013] [Photosensitive resin composition] The photosensitive resin composition of the present embodiment (sometimes simply referred to as the "resin composition" in the specification) is a resin material used as a protective film for a gallium nitride semiconductor. The photosensitive resin composition of the present embodiment contains a thermosetting resin, a photosensitizer, and a first coupling agent having an acid anhydride group.

[0014] By including the above components, the photosensitive resin composition of the present embodiment has excellent adhesion to a gallium nitride semiconductor or copper substrate when cured, and is therefore suitable for use as a protective film on a light-emitting device such as a light-emitting diode.

[0015] Each component used in the photosensitive resin composition of this embodiment will be described in detail below.

[0016] (thermosetting resin) Examples of the thermosetting resin used in the photosensitive resin composition of this embodiment include a resin containing a structural unit derived from a cyclic olefin, an acrylic resin, an epoxy resin, and a phenoxy resin.

[0017] (Cyclic olefin resin) As the resin having structural units derived from a cyclic olefin (referred to as "cyclic olefin resin P" in this specification), a polymerization reaction product or copolymerization reaction product obtained by polymerizing or copolymerizing one or more members selected from the group consisting of norbornene and norbornene derivatives can be used.

[0018] Examples of such cyclic olefin resins include resins containing structural units derived from cyclic olefins represented by formula (A).

[0019] [ka]

[0020] In formula (A), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2.

[0021] The cyclic olefin resin P contains a structural unit derived from a cyclic olefin represented by formula (A). This structural unit derived from a cyclic olefin is chemically robust. Therefore, the cyclic olefin resin P containing this structural unit as part of its structural unit undergoes little weight loss when subjected to heat treatment and is stable. As a result, the cured film obtained from the resin composition containing the cyclic olefin resin P has excellent moldability and durability.

[0022] In the structural unit represented by formula (A), R 1 ~R 4 Examples of the organic group having 1 to 30 carbon atoms that can constitute the above group include substituted or unsubstituted, straight-chain or branched-chain alkyl groups having 1 to 30 carbon atoms, and more specific examples include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, alkoxy groups, heterocyclic groups, and carboxyl groups.

[0023] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Examples of the alkenyl group include an allyl group, a pentenyl group, and a vinyl group. The alkynyl group includes, for example, an ethynyl group. Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, a neopentyloxy group, and an n-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group.

[0024] In formula (A), R 1 , R 2 , R 3 and R 4 is preferably hydrogen or an alkyl group, more preferably hydrogen. In addition, R 1 , R 2 , R 3 and R 4 The hydrogen atoms in the organic group having 1 to 30 carbon atoms may be substituted with any atomic group. For example, they may be substituted with a fluorine atom, a hydroxyl group, a carboxyl group, etc. More specifically, R 1 , R 2 , R 3 and R 4 As the organic group having 1 to 30 carbon atoms, a fluorinated alkyl group or the like may be selected. In formula (A), a1 is preferably 0 or 1, and more preferably 0.

[0025] The proportion of the structural units represented by formula (A) in all structural units of the cyclic olefin resin P is preferably 10 to 90 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %.

[0026] The cyclic olefin resin P is preferably a polymer containing structural units derived from maleic anhydride or maleimide in addition to the structural units of formula (A).

[0027] In one embodiment, the cyclic olefin resin P is a resin containing a structural unit represented by formula (A), a structural unit represented by formula (1), and a structural unit represented by formula (4) (referred to as "cyclic olefin resin P1").

[0028] [ka]

[0029] In formula (A), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2.

[0030] [ka]

[0031] In formula (1), R 11 is a group containing a terminal reactive unsaturated double bond, and R 21 is a hydrogen atom or an organic group having 1 to 3 carbon atoms.

[0032] [ka]

[0033] In equation (4), R 22 is a hydrogen atom or an organic group having 1 to 3 carbon atoms.

[0034] The cyclic olefin resin P1 contains a structural unit represented by formula (1). The structural unit represented by formula (1) is R 11 The cyclic olefin resin P1 has a group containing a terminal reactive unsaturated double bond represented by the formula (1). The terminal reactive unsaturated double bond in the structural unit of formula (1) promotes the curing reaction (polymerization reaction). Therefore, a photosensitive resin composition containing the cyclic olefin resin P1 has excellent sensitivity when subjected to photolithography, and therefore has excellent processability.

[0035] The cyclic olefin resin P1 contains a structural unit represented by formula (4). The cyclic olefin resin P1 contains the structural unit of formula (4), i.e., a structural unit having a carboxyl group. Due to this carboxyl group, the cyclic olefin resin P1 has high alkali solubility. Therefore, a photosensitive resin composition containing this cyclic olefin resin P1 has excellent sensitivity to photolithography processing and excellent processability.

[0036] In the structural unit represented by formula (1), R 11 R is a group containing a terminal reactive unsaturated double bond. This reactive unsaturated double bond serves to initiate radical polymerization, for example, by a photoradical generator. 11 Examples of the group containing a terminal reactive unsaturated double bond constituting R include a vinyl group, a vinylidene group, an acryloyl group, and a methacryloyl group. From the viewpoint of providing the cyclic olefin resin P1 with excellent sensitivity, R 11 is preferably a group containing an acryloyl group or a methacryloyl group.

[0037] The structural unit represented by formula (1) includes a structural unit represented by formula (1-1) and a structural unit represented by formula (1-2). The structural unit of formula (1) may contain either one of these structural units or both.

[0038] [ka]

[0039] In formula (1-1), Z is a group containing one or more (meth)acryloyl groups. Q is a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Examples of the substituent of the substituted alkyl group having 1 to 6 carbon atoms include a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, and a mercapto group. X represents an oxygen atom or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms. Examples of the alkylene group constituting X include a methylene group, an ethylene group, a propylene group, and a butylene group. Examples of the substituent of the substituted alkylene group having 1 to 4 carbon atoms include a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, and a mercapto group. When Q is the alkyl group and X is the alkylene group, the alkyl group of Q may be bonded to any carbon atom of the alkylene group of X to form a ring. Examples of the ring structure include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a decalin ring, a benzene ring, and a naphthalene ring. In formula (1-1), an embodiment in which X is alkylene having 1 to 4 carbon atoms and Z is a (meth)acryloyloxy group, or an embodiment in which X is an oxygen atom and Z is a (meth)acryloyl group is preferably used.

[0040] [ka]

[0041] In formula (1-2), R S is a group represented by formula (2a), R 21 is a hydrogen atom or an organic group having 1 to 3 carbon atoms.

[0042] [ka]

[0043] In formula (2a), X 10 is a divalent organic group, and R is a hydrogen atom or a methyl group. 10 The total number of carbon atoms is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10. X 10 The divalent organic group is preferably, for example, an alkylene group. Some of the -CH2- in this alkylene group may be ether groups (-O-). The alkylene group may be linear or branched, but is more preferably linear.

[0044] X 10 The divalent organic group X is more preferably a linear alkylene group having a total of 3 to 6 carbon atoms. 10 The number of carbon atoms (X 10 By appropriately selecting the chain length of the structural unit represented by formula (1-2), the structural unit represented by formula (1-2) can be more easily involved in the crosslinking reaction, thereby increasing the sensitivity.

[0045] X 10 The divalent organic group (for example, an alkylene group) may be substituted with any substituent, such as an alkyl group, an aryl group, an alkoxy group, or an aryloxy group. Also, X 10 The divalent organic group may be any group other than an alkylene group, such as a divalent group formed by linking one or more groups selected from alkylene groups, cycloalkylene groups, arylene groups, ether groups, carbonyl groups, carboxy groups, and the like.

[0046] Since the structural unit represented by formula (1) has a (meth)acryloyl group, the cyclic olefin resin P1 containing the structural unit has a good balance between sensitivity and developability. As a result, the resin composition of the present embodiment containing the cyclic olefin resin P1 has excellent processability.

[0047] R in formula (1), formula (1-1) and formula (1-2) 21is a hydrogen atom or an organic group having 1 to 3 carbon atoms. Examples of the organic group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. 21 is preferably a hydrogen atom.

[0048] R in Equation (4) 22 is a hydrogen atom or an organic group having 1 to 3 carbon atoms. Examples of the organic group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. 22 is preferably a hydrogen atom.

[0049] The proportion of the structural unit represented by formula (1) in all structural units of the cyclic olefin resin P1 is preferably 10 to 50 mol %, more preferably 15 to 40 mol %, and even more preferably 20 to 35 mol %.

[0050] The proportion of the structural unit represented by formula (4) in all structural units of the cyclic olefin resin P1 is preferably 10 to 50 mol %, more preferably 15 to 40 mol %, and even more preferably 20 to 35 mol %.

[0051] The cyclic olefin resin P1 may contain, in addition to the above structural units, a structural unit represented by formula (MA).

[0052] [ka]

[0053] In formula (MA), R 21 and R 22 are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms. Examples of the organic group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. 21 and R 22 is preferably a hydrogen atom. The structural unit represented by formula (MA) undergoes ring-opening in an alkaline developer to generate two carboxyl groups. Therefore, the cyclic olefin resin P1 can have excellent developability. When the cyclic olefin resin P1 contains a structural unit represented by formula (MA), the structural unit represented by formula (MA) preferably accounts for 3 to 40 mol %, more preferably 10 to 30 mol %, of all structural units of the cyclic olefin resin P1.

[0054] The weight-average molecular weight Mw of the cyclic olefin resin P1 is, for example, 6,000 to 18,000, preferably 7,000 to 16,000, and more preferably 8,000 to 12,000. By appropriately adjusting the weight-average molecular weight, it is possible to adjust the sensitivity and the solubility in an alkaline developer.

[0055] The cyclic olefin resin P1 can be produced (synthesized) by any method, for example, by using the polymer production method described in WO 2017 / 154439.

[0056] In one embodiment, the cyclic olefin resin P is a resin containing a structural unit represented by formula (A), a structural unit represented by formula (MA), and a structural unit represented by formula (B2) (referred to as "cyclic olefin resin P2").

[0057] [ka]

[0058] In formula (A), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom or an organic group having 1 to 30 carbon atoms; a1 is 0, 1 or 2.

[0059] [ka]

[0060] In formula (MA), R 21 and R 22 are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms.

[0061] [ka]

[0062] R in formula (B2) B1 is hydrogen or an organic group having 1 to 30 carbon atoms. B1 may be an organic group bonded via a linking group such as an ester bond, an amide bond, a ketone bond, a urea bond, or a urethane bond.

[0063] R in formula (B2) B1 Examples of the organic group constituting the formula (I) include an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, a cycloalkyl group, an alkoxy group, and a heterocyclic group.

[0064] Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl. Examples of the alkenyl group include allyl, pentenyl, and vinyl. Examples of the alkynyl group include ethynyl. Examples of the alkylidene group include methylidene and ethylidene. Examples of the aryl group include tolyl, xylyl, phenyl, naphthyl, and anthracenyl. Examples of the aralkyl group include benzyl and phenethyl. Examples of the alkaryl group include tolyl and xylyl. Examples of the cycloalkyl group include adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, an isobutoxy group, a t-butoxy group, an n-pentyloxy group, a neopentyloxy group, and an n-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group.

[0065] R in formula (B2) B1 is preferably at least one selected from the group consisting of an alkyl group, an alkenyl group, and an alkynyl group, and is preferably an alkyl group or an alkenyl group. B1 This can prevent the bonds in the resin from being cleaved, thereby improving the heat resistance of the resulting resin film.

[0066] In formula (B2), R B1 As the alkyl group, for example, it is preferably an aliphatic group formed by one or more atoms selected from the group consisting of hydrogen atoms and carbon atoms bonded via an ester bond, and more preferably a hydrocarbon group.

[0067] The cyclic olefin resin P2 may contain a structural unit derived from maleimide or a maleimide derivative, which can improve the processability and heat resistance of the resulting photosensitive resin composition.

[0068] The structural unit derived from maleimide or a maleimide derivative is preferably a structural unit derived from a maleimide-based monomer represented by the following formula (8).

[0069] [ka]

[0070] In formula (8), R 12 is a hydrogen atom or a C1 to C30 organic group. 12 Examples of the C1-C30 organic groups constituting the aryl group include hydrocarbon groups such as alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups. Examples of alkyl groups include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, pentyl groups, neopentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, and decyl groups. Examples of alkenyl groups include allyl groups, pentenyl groups, and vinyl groups. Examples of alkynyl groups include ethynyl groups. Examples of alkylidene groups include methylidene groups and ethylidene groups. Examples of aryl groups include phenyl groups and naphthyl groups. Examples of aralkyl groups include benzyl groups and phenethyl groups. Examples of alkaryl groups include tolyl groups and xylyl groups. Examples of cycloalkyl groups include adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl groups. One or more hydrogen atoms in R5 may be substituted with a halogen atom such as fluorine, chlorine, bromine, or iodine.

[0071] The weight-average molecular weight Mw of the cyclic olefin resin P2 is, for example, 6,000 to 18,000, preferably 7,000 to 16,000, and more preferably 8,000 to 12,000. By appropriately adjusting the weight-average molecular weight, it is possible to adjust the sensitivity and the solubility in an alkaline developer.

[0072] The cyclic olefin resin P2 can be produced (synthesized) by any method, for example, by using the polymer production method described in JP-A-2019-113690.

[0073] When the photosensitive resin composition of this embodiment contains the above-mentioned cyclic olefin resin P, the lower limit of the amount of the cyclic olefin resin P is, for example, 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more, based on the total solid content of the photosensitive resin composition. This can improve the heat resistance and mechanical strength of the finally obtained cured film. On the other hand, the upper limit of the content of the epoxy resin is, for example, 90% by mass or less, preferably 85% by mass or less, and more preferably 82% by mass or less, based on the total solid content of the photosensitive resin composition. This can improve patterning properties.

[0074] In this embodiment, the solid content of the photosensitive resin composition refers to the remainder excluding volatile components such as water, solvent, etc. When a solvent is included, the content relative to the total solid content of the photosensitive resin composition refers to the content relative to the total non-volatile components of the photosensitive resin composition excluding the solvent.

[0075] (acrylic resin) An example of the acrylic resin is polymethyl(meth)acrylate.

[0076] (epoxy resin) Examples of epoxy resins include phenol novolac type epoxy resins, cresol novolac type epoxy resins, cresol naphthol type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, phenoxy resins, naphthalene skeleton type epoxy resins, bisphenol A type epoxy resins, bisphenol A diglycidyl ether type epoxy resins, bisphenol F type epoxy resins, bisphenol F diglycidyl ether type epoxy resins, bisphenol S diglycidyl ether type epoxy resins, glycidyl ether type epoxy resins, cresol novolac type epoxy resins, aromatic polyfunctional epoxy resins, aliphatic epoxy resins, aliphatic polyfunctional epoxy resins, alicyclic epoxy resins, and polyfunctional alicyclic epoxy resins.

[0077] The epoxy resin may include a solid epoxy resin having two or more epoxy groups in the molecule. As the solid epoxy resin, one having two or more epoxy groups and being solid at 25°C (room temperature) can be used. This can improve the mechanical properties of the resin film of the resulting photosensitive resin composition.

[0078] The epoxy resin may also include a polyfunctional epoxy resin having three or more functional groups in the molecule (that is, a polyfunctional epoxy resin having three or more epoxy groups in one molecule).

[0079] The tri- or higher functional polyfunctional epoxy resin preferably contains one or more epoxy resins selected from the group consisting of phenol novolac epoxy resins, cresol novolac epoxy resins, triphenylmethane epoxy resins, dicyclopentadiene epoxy resins, bisphenol A epoxy resins, and tetramethylbisphenol F epoxy resins, and more preferably contains a novolac epoxy resin, which allows the resulting resin film to have an appropriate thermal expansion coefficient while improving its heat resistance.

[0080] The epoxy resin may also include a liquid epoxy resin having two or more epoxy groups in the molecule, which functions as a film-forming agent and can improve the brittleness of the resin film of the photosensitive resin composition.

[0081] The liquid epoxy resin may be an epoxy compound that has two or more epoxy groups and is liquid at room temperature of 25° C. The viscosity of this liquid epoxy resin at 25° C. may be, for example, 1 mPa·s to 8000 mPa·s, preferably 5 mPa·s to 1500 mPa·s, and more preferably 10 mPa·s to 1400 mPa·s.

[0082] The liquid epoxy resin may include, for example, one or more selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, alkyl diglycidyl ether, and alicyclic epoxy. These may be used alone or in combination of two or more. Among these, alkyl diglycidyl ether may be used from the viewpoint of reducing cracks after development.

[0083] The weight average molecular weight (Mw) of the liquid epoxy resin is not particularly limited, but is preferably, for example, 300 to 9000, and more preferably 500 to 8000. By using an epoxy resin with a relatively low molecular weight, reactivity during exposure can be increased.

[0084] The epoxy equivalent of the liquid epoxy resin is, for example, 100 g / eq or more and 200 g / eq or less, preferably 105 g / eq or more and 180 g / eq or less, and more preferably 110 g / eq or more and 170 g / eq or less, thereby improving the brittleness of the resulting resin film.

[0085] When the photosensitive resin composition of this embodiment contains the epoxy resin, the lower limit of the amount of the epoxy resin to be blended is, for example, 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more, based on the total solid content of the photosensitive resin composition. This can improve the heat resistance and mechanical strength of the finally obtained cured film. On the other hand, the upper limit of the content of the epoxy resin is, for example, 90% by mass or less, preferably 85% by mass or less, and more preferably 82% by mass or less, based on the total solid content of the photosensitive resin composition. This can improve patterning properties.

[0086] (phenoxy resin) Examples of phenoxy resins include bisphenol A phenoxy resins, bisphenol F phenoxy resins, copolymer phenoxy resins of bisphenol A and bisphenol F, biphenyl phenoxy resins, bisphenol S phenoxy resins, and copolymer phenoxy resins of biphenyl phenoxy resins and bisphenol S phenoxy resins, and mixtures of one or more of these are used. Among these, bisphenol A phenoxy resins or copolymer phenoxy resins of bisphenol A and bisphenol F are preferably used.

[0087] The weight average molecular weight (Mw) of the phenoxy resin is not particularly limited, but is preferably, for example, 10,000 to 100,000, and more preferably 20,000 to 80,000. Use of such a relatively high molecular weight phenoxy resin can impart good flexibility to the resin film and sufficient solubility in solvents.

[0088] The phenoxy resin used is preferably one that is solid at 25° C. Specifically, a phenoxy resin with a nonvolatile content of 90% by mass or more is preferably used. By using such a phenoxy resin, the mechanical properties of the cured product can be improved.

[0089] (photosensitizer) The photosensitive resin composition of this embodiment contains a photosensitizer. A photoradical polymerization initiator is used as the photosensitizer. Known compounds can be used as the photoradical polymerization initiator, such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one. -one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and other alkylphenone compounds; benzophenone, 4,4'-bis(dimethylamino)benzophenone, 2-carboxybenzophenone, and other benzophenone compounds; benzoin methyl ether, benzoin ethyl benzoin compounds such as benzoin ether, benzoin isopropyl ether, and benzoin isobutyl ether; thioxanthone compounds such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone; 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(4-ethoxynaphthyl)- Halomethylated triazine compounds such as 4,6-bis(trichloromethyl)-s-triazine and 2-(4-ethoxycarbonylnaphthyl)-4,6-bis(trichloromethyl)-s-triazine; halomethylated oxadiazole compounds such as 2-trichloromethyl-5-(2'-benzofuryl)-1,3,4-oxadiazole, 2-trichloromethyl-5-[β-(2'-benzofuryl)vinyl]-1,3,4-oxadiazole, 4-oxadiazole, and 2-trichloromethyl-5-furyl-1,3,4-oxadiazole;Biimidazole compounds such as 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole; 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, Examples of suitable photo-radical polymerization initiators include oxime ester compounds such as 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime); titanocene compounds such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium; benzoate ester compounds such as p-dimethylaminobenzoic acid and p-diethylaminobenzoic acid; and acridine compounds such as 9-phenylacridine. The photo-radical polymerization initiator may be used alone or in combination of two or more. The photoradical polymerization initiator is used in an amount of, for example, 1 to 20 parts by mass, preferably 3 to 10 parts by mass, relative to 100 parts by mass of polymer P.

[0090] (First Coupling Agent) The photosensitive resin composition of this embodiment contains a first coupling agent as an adhesion aid, which improves adhesion to the gallium nitride on which a cured film of the photosensitive resin composition is formed as a protective film.

[0091] In this embodiment, the first coupling agent is a coupling agent containing an acid anhydride as a functional group (referred to as an "acid anhydride-containing coupling agent" in this specification).

[0092] As the acid anhydride-containing coupling agent, a compound containing an alkoxysilyl group is preferably used, and an alkoxysilyl-containing alkylcarboxylic acid anhydride is preferably used. By using such a coupling agent, a photosensitive resin composition having excellent adhesion to a gallium nitride semiconductor can be obtained.

[0093] Specific examples of compounds containing an alkoxysilyl group include succinic anhydrides such as 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, 3-dimethylmethoxysilylpropyl succinic anhydride, and 3-dimethylethoxysilylpropyl succinic anhydride, dicarboxylic anhydrides such as 3-trimethoxysilylpropyl cyclohexyl dicarboxylic anhydride, 3-triethoxysilylpropyl cyclohexyl dicarboxylic anhydride, 3-dimethylmethoxysilylpropyl cyclohexyl dicarboxylic anhydride, and 3-dimethylethoxysilylpropyl cyclohexyl dicarboxylic anhydride, and phthalic anhydrides such as 3-trimethoxysilylpropyl phthalic anhydride, 3-triethoxysilylpropyl phthalic anhydride, 3-dimethylmethoxysilylpropyl phthalic anhydride, and 3-dimethylethoxysilylpropyl phthalic anhydride, and alkoxysilyl group-containing alkylcarboxylic anhydrides. These may be used alone or in combination.

[0094] Among these, succinic anhydride is preferred, alkoxysilyl group-containing succinic anhydride is more preferred, and 3-trimethoxysilylpropylsuccinic anhydride is particularly preferred. Such coupling agents optimize the molecular length and molecular structure, thereby improving the adhesion described above.

[0095] The amount of the acid anhydride-containing coupling agent added is not particularly limited, but is preferably about 0.3 to 5 mass %, more preferably about 0.4 to 4.5 mass %, and even more preferably about 1 to 4 mass %, of the total solid content of the photosensitive resin composition. By setting the amount of the acid anhydride-containing coupling agent added within this range, a protective film with particularly good adhesion to the gallium nitride semiconductor can be obtained.

[0096] If the amount of the acid anhydride-containing coupling agent added is less than the lower limit, the adhesion to the gallium nitride semiconductor may be reduced depending on the composition of the acid anhydride-containing coupling agent, etc. On the other hand, if the amount of the acid anhydride-containing coupling agent added is more than the upper limit, the photosensitivity and mechanical properties of the photosensitive resin composition may be reduced depending on the composition of the acid anhydride-containing coupling agent, etc.

[0097] In addition to such an acid anhydride-containing coupling agent, a second coupling agent may be further added.

[0098] Examples of the second coupling agent include coupling agents containing, as a functional group, an amino group, an epoxy group, an acrylic group, a methacrylic group, a mercapto group, a vinyl group, a ureido group, a sulfide group, etc. These may be used alone or in combination.

[0099] Among these, examples of amino group-containing coupling agents include bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldiethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane.

[0100] Examples of epoxy group-containing coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane.

[0101] Examples of the acrylic group-containing coupling agent include γ-(methacryloxypropyl)trimethoxysilane, γ-(methacryloxypropyl)methyldimethoxysilane, and γ-(methacryloxypropyl)methyldiethoxysilane. An example of a mercapto group-containing coupling agent is 3-mercaptopropyltrimethoxysilane.

[0102] Examples of the vinyl group-containing coupling agent include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane. An example of a ureido group-containing coupling agent is 3-ureidopropyltriethoxysilane.

[0103] Examples of sulfide group-containing coupling agents include bis(3-(triethoxysilyl)propyl)disulfide and bis(3-(triethoxysilyl)propyl)tetrasulfide.

[0104] The amount of the other coupling agent added is not particularly limited, but is preferably about 50 to 700% by mass, more preferably about 100 to 650% by mass, and even more preferably about 150 to 550% by mass of the acid anhydride-containing coupling agent. By setting the amount added within this range, the aforementioned effect of the acid anhydride-containing coupling agent is not impaired, and the addition of the other coupling agent adds another effect. As a result, the effects brought about by both coupling agents can be achieved simultaneously.

[0105] (Crosslinking agent) The photosensitive resin composition of the present embodiment preferably contains a crosslinking agent that undergoes a crosslinking reaction with the thermosetting resin by the action of activated chemical species generated from the photopolymerization initiator to form a crosslinked structure.

[0106] (Dendrimer (meth)acrylate) The photosensitive resin composition of this embodiment preferably contains a dendrimer (meth)acrylate as a crosslinking agent. By containing a dendrimer (meth)acrylate as a crosslinking agent, the cured product obtained by the crosslinking reaction with the thermosetting resin has excellent transparency. Furthermore, by containing a dendrimer (meth)acrylate, the photosensitive resin composition of this embodiment improves the mechanical strength of the resulting cured product.

[0107] Dendrimer (meth)acrylate refers to a resin that is a highly branched dendritic polymer having a core (central portion), branched chain portions bonded to the core, and terminal portions further bonded to the branched chain portions, with a three-dimensional branched structure and (meth)acryloyl groups at the ends of each branched chain.

[0108] The dendrimer (meth)acrylate used in this embodiment preferably has 6 or more (meth)acryloyl groups per molecule, more preferably 8 or more (meth)acryloyl groups, more preferably 12 or more (meth)acryloyl groups, and even more preferably 16 or more methacryloyl groups. The upper limit of the number of (meth)acryloyl groups contained in this dendrimer (meth)acrylate is not particularly limited, but is, for example, 40 or less, and preferably 30 or less.

[0109] The weight average molecular weight (Mw) of the dendrimer (meth)acrylate is preferably in the range of 100 to 30,000, and more preferably 100 to 10,000.

[0110] Examples of such dendrimer (meth)acrylates include resins having structures represented by the following formulas (5-1) to (5-8): 6 is a hydrogen atom or a methyl group, and R 7 is a hydrocarbon group having 1 to 4 carbon atoms.

[0111] [ka] [ka]

[0112] Examples of such dendrimer (meth)acrylates include "Viscoat #1000" (weight average molecular weight (Mw) 1,500 to 2,000, average number of (meth)acryloyl groups per molecule: 14), "Viscoat 1020" (weight average molecular weight (Mw) 1,000 to 3,000), and "SIRIUS501" (weight average molecular weight (Mw) 15,000 to 23,000) manufactured by Osaka Organic Chemical Co., Ltd., "SP-1106" (weight average molecular weight (Mw) 1,630, average number of (meth)acryloyl groups per molecule: 18), manufactured by MIWON Co., Ltd., and S Commercially available products such as ARTOMER's "CN2301," "CN2302" (average number of (meth)acryloyl groups per molecule: 16), "CN2303" (average number of (meth)acryloyl groups per molecule: 6), and "CN2304" (average number of (meth)acryloyl groups per molecule: 18) may also be used, as well as Nippon Steel & Sumikin Chemical's "Sdrimer HU-22," Shin-Nakamura Chemical's "A-HBR-5," Dai-ichi Kogyo Seiyaku's "New Frontier R-1150," and Nissan Chemical's "Hypertech UR-101." Dendrimer (meth)acrylates may be used singly or in combination of two or more.

[0113] The dendrimer (meth)acrylate can be blended in an amount of, for example, 5 to 100 parts by mass, and more preferably 10 to 80 parts by mass, per 100 parts by mass of polymer P.

[0114] (Other crosslinkers) The photosensitive resin composition of this embodiment may contain a crosslinking agent other than the above-mentioned dendrimer (meth)acrylate. For example, a polyfunctional (meth)acrylic compound having two or more (meth)acryloyl groups in one molecule is more preferable (however, other crosslinking agents do not fall under the category of the above-mentioned dendrimer (meth)acrylate). It is preferable to use a crosslinking agent having the same type of crosslinking group (polymerizable double bond) as the polymer in terms of achieving uniform curing properties and further improving sensitivity. There is no particular upper limit to the number of functions (the number of polymerizable double bonds) per molecule of the crosslinking agent, but it is, for example, 30 or less, preferably 20 or less.

[0115] Specific examples of such other crosslinking agents include the following:

[0116] Epoxy resins such as bisphenol A epoxy resin, 2,2'-((((1-(4-(2-(4-(oxiran-2-ylmethoxy)phenyl)propan-2-yl)phenyl)ethane-1,1-diyl)bis(4,1-phenylene))bis(oxy))bis(methylene))bis(oxirane), trimethylolpropane triglycidyl ether, and 1,1,3,3,5,5-hexamethyl-1,5-bis(3-(oxiran-2-ylmethoxy)propyl)trisiloxane.

[0117] Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, bisphenol A alkylene oxide di(meth)acrylate, bisphenol F alkylene oxide di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, ethylene oxide-added Polyfunctional (meth)acrylates such as ditrimethylolpropane tetra(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, ethylene oxide-added dipentaerythritol hexa(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added ditrimethylolpropane tetra(meth)acrylate, propylene oxide-added pentaerythritol tetra(meth)acrylate, propylene oxide-added dipentaerythritol hexa(meth)acrylate, ε-caprolactone-added trimethylolpropane tri(meth)acrylate, ε-caprolactone-added ditrimethylolpropane tetra(meth)acrylate, ε-caprolactone-added pentaerythritol tetra(meth)acrylate, and ε-caprolactone-added dipentaerythritol hexa(meth)acrylate.

[0118] Polyfunctional vinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, and ethylene oxide-added dipentaerythritol hexavinyl ether.

[0119] Vinyl ether group-containing (meth)acrylic acid esters such as 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, and 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate.

[0120] Polyfunctional allyl ethers such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, propylene glycol diallyl ether, butylene glycol diallyl ether, hexanediol diallyl ether, bisphenol A alkylene oxide diallyl ether, bisphenol F alkylene oxide diallyl ether, trimethylolpropane triallyl ether, ditrimethylolpropane tetraallyl ether, glycerin triallyl ether, pentaerythritol tetraallyl ether, dipentaerythritol pentaallyl ether, dipentaerythritol hexaallyl ether, ethylene oxide-added trimethylolpropane triallyl ether, ethylene oxide-added ditrimethylolpropane tetraallyl ether, ethylene oxide-added pentaerythritol tetraallyl ether, and ethylene oxide-added dipentaerythritol hexaallyl ether.

[0121] Allyl group-containing (meth)acrylic acid esters such as allyl (meth)acrylate. Polyfunctional (meth)acryloyl group-containing isocyanurates such as tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, alkylene oxide-added tri(acryloyloxyethyl)isocyanurate, and alkylene oxide-added tri(methacryloyloxyethyl)isocyanurate. Polyfunctional allyl group-containing isocyanurates such as triallyl isocyanurate. Polyfunctional urethane (meth)acrylates obtained by reacting polyfunctional isocyanates such as tolylene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Polyfunctional aromatic vinyls such as divinylbenzene.

[0122] Among these, trifunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate, tetrafunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate, and hexafunctional (meth)acrylates such as dipentaerythritol hexa(meth)acrylate are preferred.

[0123] (Other additives) To the photosensitive resin composition of the present embodiment, additives such as colorants, transparent inorganic fillers, surfactants, ultraviolet absorbers, antioxidants, antifoaming agents, leveling agents, mold release agents, lubricants, water repellents, flame retardants, low-shrinkage agents, and crosslinking aids may be further added as needed for the purpose of improving hardness, strength, moldability, durability, and water resistance.

[0124] Examples of the transparent inorganic filler include alumina, silica, magnesia, and zirconia.

[0125] Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, alkyl-based surfactants, and acrylic-based surfactants. The inclusion of a surfactant can improve wettability during coating, resulting in a uniform resin film and cured film.

[0126] The surfactant preferably contains a surfactant containing at least one of a fluorine atom and a silicon atom. This not only allows for a uniform resin film to be obtained (improving application properties), but also contributes to improving adhesive strength. For example, a nonionic surfactant containing at least one of a fluorine atom and a silicon atom is preferred. Commercially available surfactants that can be used include, for example, the "Megafac" series manufactured by DIC Corporation, including F-251, F-253, F-281, F-430, F-477, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561, F-562, F-563, F-565, and F-566. fluorine-containing oligomer surfactants such as F-8, F-569, F-570, F-572, F-574, F-575, F-576, R-40, R-40-LM, R-41, and R-94; fluorine-containing nonionic surfactants such as Ftergent 250 and Ftergent 251 manufactured by Neos Corporation; and silicone surfactants such as the SILFOAM® series manufactured by Wacker Chemie (e.g., SD 100 TS, SD 670, SD 850, SD 860, and SD 882).

[0127] The antioxidant is not particularly limited, and commonly used antioxidants can be used. Among these, phenolic antioxidants and amine antioxidants, which are radical chain inhibitors, are preferred. Examples of phenolic antioxidants include pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane. Among these, hindered phenolic antioxidants such as pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] are particularly preferred.

[0128] The ultraviolet absorber is not particularly limited as long as it does not impair the function of the light-emitting element, and commonly used ones can be used. Among them, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers are preferred. Examples of benzophenone-based ultraviolet absorbers include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-butylphenyl)benzotriazole, and 2-(2-hydroxy-3'-tert-butylphenyl)benzotriazole.

[0129] (Method for producing photosensitive resin composition) The method for preparing the photosensitive resin composition of this embodiment is not particularly limited, and a known method can be used depending on the components contained in the photosensitive resin composition. For example, the photosensitive resin composition can be prepared by mixing and dissolving the above components in a solvent. This allows the photosensitive resin composition to be in the form of a varnish.

[0130] The solvent is preferably an organic solvent, specifically, one or more of ketone-based solvents, ester-based solvents, ether-based solvents, alcohol-based solvents, lactone-based solvents, carbonate-based solvents, etc. can be used.

[0131] Specific examples of the solvent include propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, methyl isobutyl carbinol (MIBC), gamma butyrolactone (GBL), N-methylpyrrolidone (NMP), methyl-n-amyl ketone (MAK), diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, cyclohexanone, or mixtures thereof. The amount of solvent used is not particularly limited, but is used in an amount such that the concentration of non-volatile components becomes, for example, 10 to 70% by mass, preferably 15 to 60% by mass.

[0132] (Application) The photosensitive resin composition of this embodiment is used as a protective film for a gallium nitride semiconductor, such as a light-emitting diode. More specifically, the photosensitive resin composition of this embodiment is used to encapsulate the gallium nitride semiconductor. The light-emitting diode may be a mini-light-emitting diode or a micro-light-emitting diode. The light-emitting diode may be suitably used in various light-emitting components, lighting devices, and display devices.

[0133] The encapsulation method for the gallium nitride semiconductor of the present invention is not particularly limited and can be encapsulated by a commonly used method. For example, when the photosensitive resin composition of this embodiment is dissolved in a solvent and used as a photosensitive resin composition solution, the photosensitive resin composition solution can be applied to a substrate on which a light-emitting diode is mounted by spin coating or slit coating, and then heated and dried to form an encapsulating resin film of a predetermined thickness. Here, drying can be performed, for example, at a temperature of 70°C to 120°C for a heating time of 30 seconds to 5 minutes.

[0134] The temperature during sealing is not particularly limited, but sealing is preferably carried out at, for example, 70°C to 250°C, and more preferably 80°C to 230°C. If the sealing temperature is lower than 70°C, the curing reaction will not proceed sufficiently, and if it exceeds 250°C, the resin composition may be discolored, which is undesirable.

[0135] Furthermore, the sealing time is not particularly limited, but is preferably 10 minutes or more and less than 10 hours, and more preferably 30 minutes or more and 5 hours or less. If it is less than 10 minutes, the resin may not be cured completely. If it is more than 10 hours, productivity will be significantly reduced, which is not preferable.

[0136] The optimum combination of these sealing conditions can be selected depending on the characteristics of the light-emitting diode to be sealed, the stability required for the device, and the like.

[0137] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Examples of embodiments are given below. 1. A photosensitive resin composition used as a protective film for a gallium nitride semiconductor, comprising: a thermosetting resin; A photosensitizer and a first coupling agent having an acid anhydride group. 2. The photosensitive resin composition according to 1., The photosensitive resin composition, wherein the first coupling agent having an acid anhydride group is a silane coupling agent having an acid anhydride group. 3. The photosensitive resin composition according to 1. or 2., The photosensitive resin composition further comprises a second coupling agent different from the first coupling agent. 4. The photosensitive resin composition according to any one of 1. to 3., A photosensitive resin composition further comprising a dendrimer (meth)acrylate. 5. The photosensitive resin composition according to 1. or 2., The photosensitive resin composition includes the thermosetting resin containing at least one selected from a resin containing a structural unit derived from a cyclic olefin, an acrylic resin, an epoxy resin, and a phenoxy resin. 6. The photosensitive resin composition according to 5., the thermosetting resin includes a resin containing a structural unit derived from a cyclic olefin, The resin containing a structural unit derived from a cyclic olefin is a resin containing a structural unit represented by formula (A), a structural unit represented by formula (1), and a structural unit represented by formula (4),

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[0138] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0139] (Examples 1 to 6, Comparative Examples 1 and 2) Each component listed in Table 1 was dissolved in a solvent (PGMEA) and mixed at room temperature for 2.5 hours to obtain a mixed solution. The mixed solution was then filtered through a 0.2 μm polypropylene filter to obtain a varnish-like photosensitive resin composition with a viscosity of approximately 250 mPa s at 25°C. The viscosity of the photosensitive resin composition was measured using a cone-plate type viscometer (TV-25, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 100 rpm.

[0140] The ingredients listed in Table 1 are as follows: (resin) Resin 1: Polymer represented by formula (p1)

[0141] [ka]

[0142] (Manufacturing method of resin 1) Maleic anhydride (Nippon Shokubai Co., Ltd., 122.4 g, 1.25 mol), 2-norbornene (75 wt % toluene solution, Maruzen Petrochemical Co., Ltd., 156.8 g, 1.25 mol), and dimethyl 2,2'-azobis(2-methylpropionate) (V-601, Wako Pure Chemical Industries, Ltd., 11.5 g, 50 mmol) were weighed into an appropriately sized reaction vessel equipped with a stirrer and a condenser, and dissolved in methyl ethyl ketone (MEK, 150.8 g) and toluene (38.5 g). The solution was aerated with nitrogen for 10 minutes to remove oxygen, and then heated with stirring to 60° C. After 16 hours, MEK (320 g) was added to dilute the solution, and the solution was cooled. This reaction mixture was added dropwise to a large amount of methanol to precipitate a polymer. After filtering using a Nutsche funnel, the solid was further washed with methanol and filtered off. The resulting polymer was dried in vacuum at 70°C. The yield was 208.1 g, with a weight-average molecular weight (Mw) of 11,100 and a polydispersity (Mw / Mn) of 2.25 (referred to as the "precursor polymer" in this example). Next, the precursor polymer (10.0 g) was weighed and dissolved in MEK (30.0 g) in a suitable reaction vessel equipped with a stirrer and a condenser, followed by the addition of 2-hydroxyethyl methacrylate (HEMA, Nippon Shokubai Co., Ltd., 8.5 g, 65 mmol) and sodium acetate (1.0 g), and the mixture was heated at 70°C for 8 hours. Glycidyl methacrylate (GMA, 3.7 g, 26 mmol) was added to this reaction solution, and the mixture was stirred at 70°C for an additional 16 hours. After the reaction solution was treated with formic acid, it was added dropwise to a large amount of pure water to precipitate a polymer. The solid collected by filtration was dried in a vacuum dryer at 40°C for 16 hours, yielding 13.8 g of a pale yellow solid, Resin 1. The properties of the resulting polymer (Resin 1) were as follows: ·Weight average molecular weight (Mw): 16,200 ·Dispersion degree: 2.46

[0143] Resin 2: a polymer represented by the following formula (A-2) [ka]

[0144] (Method of manufacturing resin 2) 122.4 g (1.25 mol) of maleic anhydride, 117.6 g (1.25 mol) of 2-norbornene, and 11.5 g (0.05 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed into a reaction vessel of appropriate size equipped with a stirrer and a condenser, and dissolved in 150.8 g of methyl ethyl ketone and 77.7 g of toluene. Nitrogen was bubbled through the solution for 10 minutes to remove oxygen, and then the solution was heated at 60°C for 16 hours with stirring (polymerization step). Thereafter, 320 g of MEK was added to this solution, followed by addition to a suspension of 12.5 g (0.31 mol) of sodium hydroxide, 463.1 g (6.25 mol) of butanol, and 480 g of toluene, and mixing was carried out for 3 hours at 45°C so that 50% or more of the repeating units of the cyclic structure derived from maleic anhydride were in a ring-closed state. The mixture was then cooled to 40°C and treated with 49.0 g (0.94 mol) of an 88 wt% aqueous solution of formic acid to add protons (ring-opening step). MEK and water were then added, and the aqueous layer was separated to remove inorganic residues. Methanol and hexane were then added, and the organic layer was separated to remove unreacted monomers. Propylene glycol-1-monomethyl ether-2-acetate (PGMEA) was then added, and the methanol and butanol in the system were distilled off under reduced pressure until the residual amount was less than 1%. This yielded a PGMEA solution of a cyclic olefin resin (Resin 2) having a weight-average molecular weight Mw of 13,700 and a repeating unit represented by formula (A-2).

[0145] Resin 3: Cresol novolac epoxy resin represented by the following structure (manufactured by Nippon Kayaku Co., Ltd., EOCN-1020-55, solid at 25°C, n = 3 to 6) [ka]

[0146] (Crosslinking agent) Crosslinker 1: Dendrimer (meth)acrylate, manufactured by Osaka Organic Chemical Co., Ltd., "Viscoat #1000" (weight average molecular weight (Mw) 1,500 to 2,000, average number of (meth)acryloyl groups per molecule: 14) Crosslinker 2: Phenoxy resin represented by the following formula (weight average molecular weight is approximately 4000 (polystyrene equivalent)) [ka]

[0147] Crosslinking agent 3: bisphenol A-type phenoxy resin represented by the following formula (jER1256, manufactured by Mitsubishi Chemical Corporation, Mw: approximately 50,000) [ka]

[0148] (Photoradical polymerization initiator) Photoradical polymerization initiator 1: 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), BASF Japan Ltd., "Irgacure OXE01" (Photoacid generator) Photoacid generator 1: Triarylsulfonium borate salt (San-Apro Co., Ltd., CPI-310B) Photoacid generator 2: a diazoquinone compound represented by the following formula (GPA-250, manufactured by Daito Chemiks Co., Ltd.) [ka]

[0149] (adhesion aid) Adhesion aid 1: Trimethoxysilylpropylsuccinic anhydride, manufactured by Shin-Etsu Silicones Co., Ltd., "X-12-967C" Adhesion aid 2: A compound represented by the following structural formula, obtained by the following synthesis method: A separable flask equipped with a stirrer was charged with 200.23 g (1.00 mol) of 4-hydroxybutyl acrylate glycidyl ether and 691 g of GBL, which were stirred and dissolved at room temperature. While stirring, 96.07 g (0.95 mol) of 3-mercapto-1,2,4-triazole was added. The solution was then heated to 60°C in an oil bath and reacted at 60°C for an additional 6 hours to obtain a 30% GBL solution of a compound having the following structural formula: [ka]

[0150] Adhesion aid 3: 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403E

[0151] (surfactant) Surfactant 1: Perfluoroalkyl polymer (C4 type) (DIC, R-41) (solvent) Solvent 1: Propylene glycol monomethyl ether acetate

[0152] The resulting resin composition was measured for the following physical properties. (1. Strength measurement of cured film) (Preparation of test specimens) The photosensitive resin composition was spin-coated onto an 8-inch silicon wafer so that the film thickness after drying would be 11 μm, and then heated at 110° C. for 3 minutes to obtain a coating film. The resulting coating film was irradiated with 100 mJ / cm from a high-pressure mercury lamp. 2 After that, the film was left to stand for 30 minutes and then immersed in tetramethylammonium hydroxide for 30 seconds. After that, the film was heated at 230°C for 120 minutes in a nitrogen atmosphere for curing. This gave a cured film of the photosensitive resin composition. The obtained cured product was cut together with the silicon wafer into 6.5 mm pieces using a dicing saw, and the cut pieces were immersed in a 2% by mass aqueous solution of hydrofluoric acid to peel the cured film from the wafer. The peeled cured film was dried at 60°C for 10 hours to obtain a test piece (50 mm x 6.5 mm x 10 µm thick). (Measurement of elastic modulus) The obtained test specimens were subjected to a tensile test (extension rate: 5 mm / min) in an atmosphere of 23°C using a tensile tester (Tensilon RTC-1210A) manufactured by Orientec Co., Ltd. The elastic modulus (GPa) was calculated from the stress applied to the test specimen during elastic deformation and the tensile elongation of the test specimen.

[0153] (Measurement of breaking stress) The obtained test pieces were subjected to a tensile test (stretching speed: 5 mm / min) in an atmosphere of 23°C using a tensile tester (Tensilon RTC-1210A) manufactured by Orientec Co., Ltd. The membrane strength (MPa) was calculated from the strength at which the membrane broke.

[0154] (2. Measurement of Tensile Elongation) Test specimens were prepared in the same manner as in (Preparation of Test Specimens) in (1. Measurement of Dynamic Viscoelasticity of Cured Films) above. A tensile test was carried out on the test specimens using a tensile tester (Tensilon RTC-1210A, manufactured by Orientec Co., Ltd.) in an atmosphere of 23°C according to a method conforming to JIS K 7161, and the tensile elongation of the test specimens was measured. The elongation rate in the tensile test was 5 mm / min. The tensile elongation is expressed in %.

[0155] (3. Measurement of linear expansion coefficient and glass transition temperature of cured film) Test specimens were prepared in the same manner as in (Preparation of Test Specimens) in (1. Measurement of Dynamic Viscoelasticity of Cured Films) above. The test specimens were heated to 300°C at a heating rate of 10°C / min using a thermomechanical analyzer (TMA / SS6000, manufactured by Seiko Instruments Inc.). The thermal expansion coefficients of the obtained test specimens were measured. The glass transition temperature Tg (unit: °C) of the cured product was then calculated from the inflection point of the temperature-thermal expansion coefficient graph obtained from the measurement results. A higher Tg of the cured film means that the cured film is more stable against heat.

[0156] (4. Evaluation of adhesion to Cu substrate) (4.1 Preparation of Evaluation Test Sample A) As a base substrate, a silicon wafer piece was prepared, on the surface of which a Cu film (Cu plating film) having a thickness of 1.5 μm was formed. Subsequently, the resulting photosensitive resin composition was spin-coated onto the base substrate to form a spin-coated film (liquid film). The liquid film was dried by heating at 110°C for 3 minutes to obtain a photosensitive resin film having a thickness of 5 to 30 μm. Next, the obtained photosensitive resin film was exposed to i-rays with a wavelength of 365 nm at 100 mJ / cm using an automatic exposure machine. 2 The entire surface was exposed to an exposure amount of 1000 ppm. After that, the silicon wafer was left to stand for 30 minutes, and then immersed in tetramethylammonium hydroxide for 30 seconds. Thereafter, the silicon wafer was heated in a nitrogen atmosphere at 230° C. for 120 minutes to cure the photosensitive resin film, and an evaluation test sample A was obtained in which a cured film was formed on the surface of the base substrate.

[0157] (4.2 Measurement of adhesion to Cu substrate) The adhesion between the cured film of the obtained evaluation test sample A and the Cu film on the surface of the base substrate was evaluated. First, 100 1mm square grids were created on the cured film using a CrossCut-Master 3000 (manufactured by Allgood Co., Ltd.) with a cutter knife. Cellophane adhesive tape (manufactured by Sekisui Chemical Co., Ltd., product name: LP-18) was attached to the surface of the cured film, and then the edge of the tape was held and peeled off at a 60° angle. This operation was repeated three times, first in the vertical direction of the grid, then in a horizontal direction at a 90° angle, and then again in the vertical direction. The number of grids (grids) that peeled off from the substrate surface was then counted. The cured film was then exposed to an environment of 85°C and 85% humidity for 1000 hours in a HUMIDITY CABINET (Tabaiespec Co., Ltd.), after which the adhesion evaluation described above was performed using cellophane adhesive tape (same as above). The evaluation results are shown in Table 1 according to the following criteria. ○: The number of peeled squares was 0-10 after curing and 0-10 after exposure to 85°C and 85% humidity. △: The number of peeled squares was 0-10 after curing, and 11-100 after exposure to 85°C and 85% humidity. ×: The number of peeled squares was 11 to 100 after curing and 11 to 100 after exposure to 85°C and 85% humidity.

[0158] (5. Evaluation of adhesion to GaN substrate) (5.1 Preparation of Evaluation Test Sample B) Evaluation test sample B was fabricated in the same manner as described above in "4.1 Fabrication of evaluation test sample A," except that a sapphire substrate having a GaN layer formed on its surface was used as the base substrate. (5.2 Measurement of adhesion to GaN substrate) Using the evaluation test sample B obtained above, the adhesion to the GaN substrate was measured using the same method and evaluation criteria as in "4.2 Measurement of adhesion to Cu substrate" above. The results are shown in Table 1.

[0159] [Table 1]

[0160] Comparison of Examples 1 to 6 with Comparative Examples 1 and 2 revealed that the resin compositions of the Examples containing a coupling agent having an acid anhydride group had good adhesion to Cu substrates and GaN substrates. Furthermore, comparison of Examples 1 to 3 with Example 4 revealed that when the blending amount of a coupling agent having an acid anhydride group was small, adhesion to the substrate after exposure to an environment at a temperature of 85°C and a humidity of 85% was slightly poor.

Claims

1. A photosensitive resin composition used as a protective film for a gallium nitride semiconductor, comprising: a thermosetting resin; A photosensitizer and a first coupling agent having an acid anhydride group; the thermosetting resin includes a resin containing a structural unit derived from a cyclic olefin, The resin containing a structural unit derived from a cyclic olefin is a resin containing a structural unit represented by formula (A), a structural unit represented by formula (1), and a structural unit represented by formula (4), 【Chemistry 1】 In formula (A), R 1 , R 2 , R 3 and R 4 each independently represent a hydrogen atom or an organic group having 1 to 30 carbon atoms; a 1 represents 0, 1 or 2; 【Chemistry 2】 In formula (1), R 11 is a group containing a terminal reactive unsaturated double bond, R 21 is a hydrogen atom or an organic group having 1 to 3 carbon atoms, 【Transformation 3】 In formula (4), R 22 is a hydrogen atom or an organic group having 1 to 3 carbon atoms. Photosensitive resin composition.

2. The photosensitive resin composition according to claim 1, The photosensitive resin composition, wherein the first coupling agent having an acid anhydride group is a silane coupling agent having an acid anhydride group.

3. The photosensitive resin composition according to claim 1 or 2, The photosensitive resin composition further comprises a second coupling agent different from the first coupling agent.

4. The photosensitive resin composition according to any one of claims 1 to 3, A photosensitive resin composition further comprising a dendrimer (meth)acrylate.

5. The photosensitive resin composition according to any one of claims 1 to 4, The resin containing a structural unit derived from a cyclic olefin further contains a structural unit represented by formula (MA): 【Chemistry 4】 In formula (MA), R ２１ and R ２２ are each independently a hydrogen atom or an organic group having 1 to 3 carbon atoms.

6. The photosensitive resin composition according to any one of claims 1 to 5, The structural unit represented by formula (1) includes at least one selected from the structural unit represented by formula (1-1) and the structural unit represented by formula (1-2), 【Transformation 5】 In formula (1-1), Z is a group containing at least one (meth)acryloyl group, Q is a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; X represents an oxygen atom or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms; When Q is the alkyl group and X is the alkylene group, Q and X may be condensed to form a cyclic group; R ２１ is a hydrogen atom or an organic group having 1 to 3 carbon atoms, 【Transformation 6】 In formula (1-2), R Ｓ is a group represented by formula (2a), R ２１ is a hydrogen atom or an organic group having 1 to 3 carbon atoms, 【Transformation 7】 In formula (2a), X １０ is a divalent organic group, and R is a hydrogen atom or a methyl group.

7. The photosensitive resin composition according to claim 6, The photosensitive resin composition includes the structural unit represented by the formula (1) above, and the structural unit represented by the formula (1-1) above and the structural unit represented by the formula (1-2).

8. The photosensitive resin composition according to any one of claims 1 to 7, A photosensitive resin composition further comprising a crosslinking agent.

9. A substrate; a gallium nitride semiconductor disposed on the substrate; a protective film that protects at least a portion of the substrate and the gallium nitride semiconductor; A semiconductor device comprising: A semiconductor device, wherein the protective film is made of a cured product of the photosensitive resin composition according to claim 1 .

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