Photosensitive resin composition, cured product, and semiconductor element

Abstract

Provided is photosensitive resin composition, containing a maleimide resin, a (meth)acrylic monomer, a photopolymerization initiator, and an organic solvent, wherein the maleimide resin is a reaction product of tetracarboxylic dianhydride (a1), amine (a2), and maleic anhydride (a3). The amine (a2) includes dimer diamine, the (meth)acrylic monomer includes a bifunctional (meth)acrylic monomer, and the organic solvent includes a high-boiling solvent with a boiling point of 150–200°C.

Description

Photosensitive resin composition, cured product, and semiconductor element

[0001] The present disclosure relates to a photosensitive resin composition, a cured product, and a semiconductor device.

[0002] As semiconductor elements become more highly integrated, smaller, and more minute, insulating films used in surface protection layers, interlayer insulating layers, rewiring layers, and the like of semiconductor elements are required to have better electrical properties, heat resistance, mechanical properties, and the like. As materials for forming insulating films having these properties, photosensitive resin compositions containing alkali-soluble resins have been developed (see, for example, Patent Documents 1, 2, and 3). These photosensitive resin compositions are applied to a substrate and dried to form a resin film, which is then exposed to light and developed to obtain a patterned resin film (a patterned resin film). The patterned resin film can then be heat-cured to form a patterned cured film (a patterned cured film), which can be used as an insulating film.

[0003] JP 2008-309885 A JP 2007-057595 A International Publication No. 2010 / 073948

[0004] In modules requiring high-speed transmission, insulating films used in rewiring layers, etc., are required to have low dielectric properties (low dielectric constant and low dielectric dissipation factor) to support high frequencies. Furthermore, thick films are required in terms of impedance. However, the present inventors have discovered that when conventional photosensitive resin compositions are used, it is not possible to form thick insulating layers, and even if thick insulating films are formed, there are problems such as poor via opening properties and insufficient low dielectric properties. Furthermore, the present inventors have discovered that when thick coating films are formed using conventional photosensitive resin compositions, there is a problem of poor surface smoothness of the coating film. Poor surface smoothness of the coating film results in uneven thickness when laminated, which can cause problems such as wiring formation problems and cracks during reliability tests.

[0005] The present disclosure aims to provide a photosensitive resin composition that has low dielectric properties, can improve the smoothness of the coating film surface when a thick coating film is formed, and can improve the via opening property when a thick insulating film is formed, a cured product of the photosensitive resin composition, and a semiconductor element.

[0006] One aspect of the present disclosure relates to the following photosensitive resin composition, a cured product of the photosensitive resin composition, and a semiconductor device. [1] A photosensitive resin composition containing a maleimide resin, a (meth)acrylic monomer, a photopolymerization initiator, and an organic solvent, wherein the maleimide resin is a reaction product of a tetracarboxylic dianhydride (a1), an amine (a2), and maleic anhydride (a3), the amine (a2) comprises a dimer diamine, the (meth)acrylic monomer comprises a bifunctional (meth)acrylic monomer, and the organic solvent comprises a high-boiling-point solvent having a boiling point of 150 to 200°C. [2] The photosensitive resin composition according to [1] above, wherein the nonvolatile components are 45 to 70% by mass. [3] The photosensitive resin composition according to [1] or [2] above, wherein the viscosity at 25°C is 400 to 4,000 mPa·s. [4] A cured product of the photosensitive resin composition according to any one of [1] to [3] above. [5] A semiconductor device comprising a rewiring layer including an insulating film made of a cured product of the photosensitive resin composition according to any one of [1] to [3] above. [6] The semiconductor device according to [5] above, wherein the insulating film has a thickness of 15 μm or more.

[0007] According to the present disclosure, it is possible to provide a photosensitive resin composition that has low dielectric properties, can improve the smoothness of the coating film surface when a thick coating film is formed, and can improve the via opening property when a thick insulating film is formed, a cured product of the photosensitive resin composition, and a semiconductor element.

[0008] Preferred embodiments of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments and can be implemented in various modifications within the scope of the present disclosure.

[0009] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper or lower limit of a numerical range in another stage. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0010] In this specification, the terms "layer" and "film" include not only structures with shapes formed over the entire surface when observed in a plan view, but also structures with shapes formed on a portion of the surface. The term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0011] In this specification, "(meth)acryloyl" means at least one of "acryloyl" and its corresponding "methacryloyl", and the same applies to other similar expressions such as (meth)acrylic acid and (meth)acrylate.

[0012] [Photosensitive Resin Composition] The photosensitive resin composition according to this embodiment contains a maleimide resin (hereinafter also referred to as "component (A)"), a (meth)acrylic monomer (hereinafter also referred to as "component (B)"), a photopolymerization initiator (hereinafter also referred to as "component (C)"), and an organic solvent (hereinafter also referred to as "component (D)"). The maleimide resin is a reaction product of a tetracarboxylic dianhydride (a1), an amine (a2), and maleic anhydride (a3), and the amine (a2) includes a dimer diamine. The (meth)acrylic monomer includes a bifunctional (meth)acrylic monomer. The organic solvent includes a high-boiling-point solvent having a boiling point of 150 to 200°C.

[0013] The photosensitive resin composition according to this embodiment may further contain, as necessary, a coupling agent (hereinafter also referred to as "component (E)"), a polymerization inhibitor (hereinafter also referred to as "component (F)"), a thermal polymerization initiator, a crosslinking agent, a rust inhibitor, and the like. The photosensitive resin composition according to this embodiment is a negative-type photosensitive resin composition, and a cured product of the photosensitive resin composition can be suitably used as an insulating film having vias, and can be suitably used as a thick insulating film (e.g., 15 μm or more). The insulating film is suitable as a rewiring layer in semiconductor packages such as automotive fan-out wafer level packages (FOWLPs). Each component used in the photosensitive resin composition according to this embodiment will be described in more detail below.

[0014] (Component (A): Maleimide Resin) The maleimide resin according to this embodiment can be obtained by reacting a tetracarboxylic dianhydride (a1) (hereinafter also referred to as "component (a1)"), an amine (a2) (hereinafter also referred to as "component (a2)"), and maleic anhydride (a3) ​​(hereinafter also referred to as "component (a3)"). That is, the component (A) is a maleimide resin obtained by reacting the components (a1), (a2), and (a3). Here, the component (a2) contains dimer diamine. The component (A) may have multiple maleimide groups in the molecule. The component (A) may be a bismaleimide resin. The component (A) may be used alone or in combination of two or more types.

[0015] The tetracarboxylic dianhydride of component (a1) can be any known polyimide raw material. Examples of component (a1) include pyromellitic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone ... ,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene- 2,3,5,6-tetracarboxylic dianhydride, bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid) 1,4-phenylene, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 4,4'-(ethyne-1,2-diyl)diphthalic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, dicyclohexyl-3,4,3',4'-tetracarbo Examples of the component (a1) include norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic dianhydride, 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic-5,5',6,6'-dianhydride, and 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride. Among these, pyromellitic anhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride are preferred from the viewpoints of heat resistance and ease of availability. The component (a1) can be used alone or in combination of two or more.

[0016] The component (a2) contains dimer diamine. As described in, for example, Japanese Patent Application Laid-Open No. 9-12712, dimer diamine is a compound derived from a dimer acid, which is a dimer of an unsaturated fatty acid such as oleic acid. By using dimer diamine as the component (a2), the dielectric properties of the cured product can be reduced. In this embodiment, any known dimer diamine can be used without particular limitation. The dimer diamine preferably contains, for example, at least one of a compound represented by the following general formula (1) and a compound represented by the following general formula (2):

[0017]

[0018] In formulas (1) and (2), m, n, p, and q each represent an integer of 1 or greater selected so that m+n=6 to 17 and p+q=8 to 19, and the bond shown by a dashed line represents a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by a dashed line is a carbon-carbon double bond, formulas (1) and (2) have a structure in which the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond is reduced by one from the number shown in formulas (1) and (2).

[0019] The dimer diamine may be one represented by the above general formula (2), particularly a compound represented by the following formula (3), from the viewpoints of solubility in organic solvents, heat resistance, heat-resistant adhesion, low viscosity, etc.

[0020] Commercially available dimer diamine products include, for example, PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by Croda Japan Co., Ltd.).

[0021] The component (a2) may contain an amine other than dimer diamine (hereinafter also referred to as "second amine"). The second amine is an amine that does not fall under the category of the above-mentioned dimer diamine. The second amine may be a diamine or triamine, or may be a diamine. By using an alicyclic diamine as the second amine, the dielectric constant can be further reduced. By using an aromatic diamine as the second amine, the elastic modulus, Tg, and CTE of the cured product can be improved.

[0022] When the second amine is a diamine, examples of the diamine include 1,3-diaminopropane, norbornanediamine, 4,4'-methylenedianiline, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis[3-fluoro-4-aminophenyl]fluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 4,4'-(hexafluoroisopropylidene)dianiline, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 ２，６]decane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), 1,1-bis(4-aminophenyl)cyclohexane, 2,7-diaminofluorene, 4,4'-ethylenedianiline, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2-ethyl-6-methylaniline), 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2'-dimethylbiphenyl-4,4'-diamine, (4,4'-diamino)diphenyl ether, (3,3'-diamino)diphenyl ether, paraphenylenediamine, orthophenylenediamine, metaphenylenediamine, 2,2'-dimethylbiphenyl-4,4'-diamine, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, etc. These may be used alone or in combination of two or more.

[0023] When the second amine is a triamine, examples of the triamine include tris(aminomethyl)amine, tris(2-aminoethyl)amine, tris(2-aminopropyl)amine, 2-(aminomethyl)-2-methyl-1,3-propanediamine, trimer triamine, 3,4,4'-triaminodiphenyl ether, 1,2,4-triaminobenzene, 1,3,5-triaminobenzene, 1,2,3-triaminobenzene, 1,3,5-triazine-2,4,6-triamine, 2,4,6-triaminopyrimidine, 1,3,5-tris(4-aminophenyl)benzene, and 1,3,5-tris(4-aminophenoxy)benzene. Among these, from the viewpoint of photocurability, aliphatic amines and alicyclic amines are preferred, and norbornanediamine, isophoronediamine, and tris(2-aminoethyl)amine are more preferred. These may be used alone or in combination of two or more.

[0024] The second amine may include one or both of the above-mentioned diamines and triamines, or may include an amine other than the diamines and triamines.

[0025] In component (a2), the molar ratio of the second amine to the total amount of amines (moles of second amine / (moles of dimer diamine+moles of second amine)) may be 0.70 or less, or may be 0.50 or less. When this ratio is 0.70 or less, the dielectric properties of the cured product can be further reduced.

[0026] When the second amine contains a diamine, the molar ratio of the diamine in the second amine to the total amount of diamine in component (a2) (number of moles of diamine in the second amine / (number of moles of dimer diamine + number of moles of diamine in the second amine)) may be 0.70 or less, or may be 0.50 or less. When this ratio is 0.70 or less, the dielectric properties of the cured product can be further reduced.

[0027] Component (A) can be produced by various known methods. For example, components (a1) and (a2) are first subjected to a polyaddition reaction at a temperature of about 60 to 120°C, preferably 70 to 90°C, for typically about 0.1 to 2 hours, preferably 0.1 to 1.0 hour. The resulting polyaddition product is then subjected to an imidization reaction, i.e., a dehydration ring-closing reaction, at a temperature of about 80 to 250°C, preferably 100 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours. The product of the dehydration ring-closing reaction is then subjected to a maleimidization reaction, i.e., a dehydration ring-closing reaction, with component (a3) ​​at a temperature of about 60 to 250°C, preferably 80 to 200°C, for about 0.5 to 30 hours, preferably 0.5 to 10 hours, to obtain the desired component (A).

[0028] In the imidization reaction or maleimidization reaction, various known reaction catalysts, dehydrating agents, and organic solvents can be used.

[0029] Examples of the reaction catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, heterocyclic tertiary amines such as pyridine, picoline, isoquinoline, and organic acids such as methanesulfonic acid, paratoluenesulfonic acid monohydrate, etc. Examples of the dehydrating agent include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides such as benzoic anhydride.

[0030] Examples of the organic solvent used in the reaction include aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; ketone-based solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclopentanone, cyclohexanone, isophorone, and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve, ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, butyl formate, and γ-butyrolactone; ethylene glycol mono-n-butyl ether, Examples of the organic solvent include glycol ether solvents such as ethylene glycol mono-isobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-isobutyl ether, triethylene glycol monoethyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether; and nitrogen-containing compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide. These organic solvents can be used alone or in combination of two or more.

[0031] The organic solvent used in the reaction preferably has a boiling point of 150 to 200° C. Examples of organic solvents having a boiling point of 150 to 200° C. include 1,2,3,5-tetramethylbenzene (boiling point: 198° C.), n-propylbenzene (boiling point: 160° C.), 2-ethyltoluene (boiling point: 164° C.), 3-ethyltoluene (boiling point: 158° C.), 4-ethyl-m-xylene (boiling point: 186° C.), 1,2,3-trimethylbenzene (hemimellitene, boiling point: 176° C.), phenetole (ethoxybenzene) (boiling point: 173° C.), cumene (boiling point: 152° C.), and 1,2,4-trimethylbenzene. Examples of suitable organic solvents include methyl ether (pseudocumene, boiling point: 169°C), 1,3,5-trimethylbenzene (mesitylene, boiling point: 165°C), anisole (boiling point: 154°C), butyl cellosolve (boiling point: 171°C), methyl carbitol (boiling point: 194°C), dipropylene glycol monomethyl ether (boiling point: 188°C), dipropylene glycol dimethyl ether (boiling point: 171°C), N,N-dimethylformamide (boiling point: 153°C), and N,N-dimethylacetamide (boiling point: 165°C). Examples of suitable organic solvents having a boiling point of 150 to 200°C include petroleum-based solvents such as solvent naphtha (boiling point: 150 to 185°C), which is a distillation component of naphtha. The solvent naphtha may contain trimethylbenzene. Specific examples of solvent naphtha include T-SOL100 (trade name, manufactured by ENEOS Corporation), Swasol 1000 (trade name, manufactured by Cosmo Matsuyama Oil Co., Ltd.), and Ipsol 100 (trade name, manufactured by Idemitsu Kosan Co., Ltd.).

[0032] Component (A) can be purified by various known methods to increase its purity. For example, first, component (A) dissolved in an organic solvent and pure water are placed in a separatory funnel. The separatory funnel is then shaken and allowed to stand. Subsequently, the aqueous layer and the organic layer are separated, and only the organic layer is recovered, thereby purifying component (A).

[0033] The assumed structure of component (A) produced by the above method is shown in general formula (4) below.

[0034] In general formula (4), each X independently represents a tetravalent organic group, each Y independently represents a divalent organic group, and a represents an integer of 1 or greater. However, at least one of the multiple Ys represents the divalent organic group derived from the dimer diamine. Furthermore, X and Y may be an aliphatic group, an organic group having an alicyclic structure, or an aromatic ring, and may contain a heteroatom.

[0035] The molecular weight of component (A) can be controlled by the number of moles of component (a1) and component (a2), and the smaller the number of moles of component (a1) is relative to the number of moles of component (a2), the smaller the molecular weight can be. For the purpose of easily achieving the effects of the present disclosure, the number of moles of component (a1) per mole of component (a2), i.e., [number of moles of component (a1)] / [number of moles of component (a2)], is usually in the range of about 0.30 to 0.95, preferably 0.50 to 0.85.

[0036] From the viewpoint of solubility in solvents and heat resistance, the molecular weight of component (A) is preferably a weight average molecular weight (Mw) of 3,000 to 40,000, more preferably 4,000 to 30,000, and even more preferably 5,000 to 28,000, or 7,000 to 27,000. A weight average molecular weight of 40,000 or less tends to provide good solubility in organic solvents, while a weight average molecular weight of 3,000 or more tends to provide a sufficient effect of improving heat resistance. Mw can be measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene.

[0037] From the viewpoint of further improving the balance between low dielectric properties and micro-processability, the content of component (A) is preferably more than 50 parts by mass, and may be 55 to 99 parts by mass, 60 to 96 parts by mass, 70 to 92 parts by mass, or 80 to 90 parts by mass, where the total amount of component (A) and component (B) is 100 parts by mass.

[0038] (Component (B): (meth)acrylic monomer) The (meth)acrylic monomer is a compound having a (meth)acryloyl group. The component (B) is a compound having one or more (meth)acryloyl groups, and may be a polyfunctional compound having two or more (meth)acryloyl groups. The component (B) contains at least a bifunctional (meth)acrylic monomer having two (meth)acryloyl groups. When the component (B) contains a bifunctional (meth)acrylic monomer, the photocurability is improved, the component can be cured with a low exposure dose, and it becomes possible to open minute vias. When the component (B) is a polyfunctional compound, for example, the components (B) can crosslink not only with each other but also with the component (A) during exposure of the photosensitive layer. The component (B) can be used alone or in combination of two or more types.

[0039] Examples of bifunctional (meth)acrylic monomers include tricyclodecane dimethanol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, dioxane glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dipentaerythritol di(meth)acrylate, ethoxylated isocyanuric acid di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, etc. Among these, tricyclodecane dimethanol di(meth)acrylate is preferred from the viewpoints of low dielectric properties and heat resistance.

[0040] The component (B) may contain another (meth)acrylic monomer other than the bifunctional (meth)acrylic monomer. Examples of the other (meth)acrylic monomer include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tris-(2-(meth)acryloyloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and ethoxylated trimethylolpropane tri(meth)acrylate. Among these, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and tris-(2-(meth)acryloyloxyethyl)isocyanurate are preferred from the viewpoints of low dielectric properties and heat resistance.

[0041] From the viewpoint of further improving the balance between low dielectric properties and micro-processability, the content of component (B) is preferably less than 50 parts by mass, and may be 1 to 40 parts by mass, 2 to 30 parts by mass, 3 to 20 parts by mass, or 5 to 15 parts by mass, when the total amount of component (A) and component (B) is 100 parts by mass.

[0042] From the viewpoint of low dielectric properties and photocurability, the content of the bifunctional (meth)acrylic monomer is preferably less than 50 parts by mass, and may be 1 to 40 parts by mass, 2 to 30 parts by mass, 3 to 20 parts by mass, or 5 to 15 parts by mass, relative to 100 parts by mass of the total amount of the (A) component and the (B) component.

[0043] (Component (C): Photopolymerization Initiator) The photopolymerization initiator (hereinafter also referred to as "component (C)") is not particularly limited as long as it is a compound that initiates polymerization upon irradiation with actinic rays (ultraviolet rays, etc.), and examples thereof include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, intramolecular hydrogen abstraction photopolymerization initiators, and oxime ester-based photopolymerization initiators.

[0044] Alkylphenone-based photopolymerization initiators are commercially available, for example, from IGM Resins B.V. as Omnirad 651, Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127, Omnirad 907, Omnirad 369, Omnirad 379EG, etc. Acylphosphine oxide-based photopolymerization initiators are commercially available, for example, from IGM Resins B.V. as Omnirad 819, Omnirad TPO H, etc. Intramolecular hydrogen abstraction photopolymerization initiators are commercially available, for example, from IGM Resins B.V. Omnirad MBF, Omnirad 754, etc. manufactured by BASF Japan Ltd. Oxime ester photopolymerization initiators are commercially available, for example, as Irgacure OXE01, Irgacure OXE02, etc. manufactured by BASF Japan Ltd. In order to promote the photoreaction, a titanocene photopolymerization initiator (for example, Irgacure 784 manufactured by BASF Japan Ltd.) may be used in combination.

[0045] From the viewpoints of photocurability and storage stability, the content of the component (C) may be 0.1 to 10 parts by mass, 0.5 to 8 parts by mass, or 1 to 5 parts by mass relative to 100 parts by mass of the total amount of the component (A) and the component (B).

[0046] (Component (D): Organic Solvent) The photosensitive resin composition according to this embodiment contains an organic solvent for dissolving and dispersing each component. This facilitates application of the photosensitive resin composition onto a substrate, enabling the formation of a coating film of uniform thickness. The component (D) contains a high-boiling solvent with a boiling point of 150 to 200°C, in order to improve the smoothness of the coating film surface when a thick coating film is formed, and to improve the via opening properties when a thick insulating film is formed. The component (D) may be used alone or in combination of two or more types.

[0047] Examples of high boiling point solvents having a boiling point of 150 to 200°C include organic solvents having a boiling point of 150 to 200°C, such as 1,2,3,5-tetramethylbenzene (boiling point: 198°C), n-propylbenzene (boiling point: 160°C), 2-ethyltoluene (boiling point: 164°C), 3-ethyltoluene (boiling point: 158°C), 4-ethyl-m-xylene (boiling point: 186°C), 1,2,3-trimethylbenzene (hemimellitene, boiling point: 176°C), phenetole (ethoxybenzene) (boiling point: 173°C), cumene (boiling point: 152°C), 1,2 Examples of suitable organic solvents include 1,4-trimethylbenzene (pseudocumene, boiling point: 169°C), 1,3,5-trimethylbenzene (mesitylene, boiling point: 165°C), anisole (boiling point: 154°C), butyl cellosolve (boiling point: 171°C), methyl carbitol (boiling point: 194°C), dipropylene glycol monomethyl ether (boiling point: 188°C), dipropylene glycol dimethyl ether (boiling point: 171°C), N,N-dimethylformamide (boiling point: 153°C), and N,N-dimethylacetamide (boiling point: 165°C). Furthermore, examples of organic solvents having a boiling point of 150 to 200°C include petroleum-based solvents such as solvent naphtha (boiling point: 150 to 185°C), which is a distillation component of naphtha. Specific examples of solvent naphtha are as described above. Among these, solvent naphtha, pseudocumene, and mesitylene are preferred from the viewpoint of availability. The high-boiling solvent having a boiling point of 150 to 200°C may have a boiling point of 150 to 190°C or 150 to 185°C, from the viewpoint of further improving the smoothness of the coating film surface when a thick coating film is formed and further improving the via opening property when a thick insulating film is formed.

[0048] Component (D) may contain a solvent other than the high-boiling solvent having a boiling point of 150 to 200° C. Examples of other solvents include ketones such as methyl ethyl ketone and cyclopentanone; aromatic hydrocarbons such as toluene and xylene; glycol ethers such as methyl cellosolve and propylene glycol monomethyl ether; esters such as ethyl acetate and butyl acetate; and nitrogen-containing compounds.

[0049] From the viewpoints of further improving the smoothness of the coating film surface when a thick coating film is formed and further improving the via opening property when a thick insulating film is formed, the content of component (D) is preferably an amount such that the nonvolatile components in the photosensitive resin composition are 45 to 70 mass%, 50 to 65 mass%, or 50 to 60 mass%. Here, the nonvolatile components refer to nonvolatile components excluding volatile substances (water, solvents, etc.) contained in the photosensitive resin composition, and also include components that are liquid, syrup-like, or waxy at room temperature (around 25°C). The nonvolatile components of the photosensitive resin composition can be measured by the method described in the Examples.

[0050] The content of the high-boiling solvent having a boiling point of 150 to 200°C may be 50 to 100 mass%, 60 to 100 mass%, or 70 to 100 mass%, based on the total amount of component (D), from the viewpoints of further improving the smoothness of the coating film surface when a thick coating film is formed and further improving the via opening property when a thick insulating film is formed.

[0051] (Component (E): Coupling Agent) The photosensitive resin composition according to this embodiment may further contain a coupling agent from the viewpoint of improving the adhesion of a cured product of the photosensitive resin composition. Component (E) may be a silane coupling agent. The silane coupling agent may have, for example, a vinyl group, an epoxy group, a styryl group, an acryloyl group, a methacryloyl group, an amino group, a ureido group, an isocyanate group, an isocyanurate group, a mercapto group, or the like.

[0052] Examples of silane coupling agents having a vinyl group include KBM-1003 and KBE-1003 (trade names manufactured by Shin-Etsu Chemical Co., Ltd.; the same applies hereinafter). Examples of silane coupling agents having an epoxy group include KBM-303, 402, 403, KBE-402, 403, X-12-981S, and X-12-984S. Examples of silane coupling agents having a styryl group include KBM-1403. Examples of silane coupling agents having a methacryloyl group include KBM-502, 503, KBE-502, and 503. Examples of silane coupling agents having an acryloyl group include KBM-5103, X-12-1048, and X-12-1050. Examples of silane coupling agents having an amino group include KBM-602, 603, 903, 573, 575, KBE-903, 9103P, and X-12-972F. Examples of silane coupling agents having a ureido group include KBE-585. Examples of silane coupling agents having an isocyanate group include KBE-9007 and X-12-1159L. Examples of silane coupling agents having an isocyanurate group include KBM-9659. Examples of silane coupling agents having a mercapto group include KBM-802, 803, X-12-1154, and X-12-1156. The silane coupling agent may be a silane coupling agent having a methacryloyl group. The silane coupling agents may be used alone or in combination of two or more.

[0053] The content of the component (E) may be 0.01 to 10 parts by mass, 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass relative to 100 parts by mass of the total amount of the components (A) and (B).

[0054] (Component (F): Polymerization Inhibitor) The photosensitive resin composition according to this embodiment may further contain a polymerization inhibitor from the viewpoint of storage stability.

[0055] Examples of component (F) include 4-tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy radical, p-methoxyphenol, diphenyl-p-benzoquinone, benzoquinone, hydroquinone, pyrogallol, phenothiazine, resorcinol, ortho-dinitrobenzene, para-dinitrobenzene, meta-dinitrobenzene, phenanthraquinone, N-phenyl-2-naphthylamine, cupferron, 2,5-toluquinone, tannic acid, parabenzylaminophenol, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, and nitrosamines. The polymerization inhibitor may be used alone or in combination of two or more.

[0056] The content of the component (F) may be 0.01 to 10 parts by mass, 0.05 to 5 parts by mass, or 0.10 to 2 parts by mass relative to 100 parts by mass of the total amount of the components (A) and (B).

[0057] (Rust inhibitor) The photosensitive resin composition according to this embodiment may further contain a rust inhibitor in order to suppress corrosion or prevent discoloration of copper wiring. Examples of the rust inhibitor include triazole derivatives such as benzotriazole, and tetrazole derivatives. The rust inhibitor may be used alone or in combination of two or more.

[0058] The content of the rust inhibitor may be 0.01 to 10 parts by mass, 0.03 to 5 parts by mass, or 0.05 to 3 parts by mass, per 100 parts by mass of the total amount of components (A) and (B).

[0059] (Crosslinking Agent) The photosensitive resin composition according to this embodiment may contain a crosslinking agent other than the component (B). The crosslinking agent may be a polymerizable crosslinking agent. The polymerizable group may be a photopolymerizable group or a thermally polymerizable group. Examples of the polymerizable group include an allyl group and a vinyl group from the viewpoint of dielectric properties and heat resistance. The crosslinking agent may be a polyfunctional compound having two or more polymerizable groups. Furthermore, the crosslinking agent may crosslink not only with itself but also with the component (A) or the component (B), for example, during exposure of the photosensitive layer. Furthermore, the crosslinking agent may crosslink with itself, for example, during heating of the resin film after pattern formation. The crosslinking agent may be used alone or in combination of two or more.

[0060] Examples of polymerizable crosslinking agents having an allyl group include 1,3,4,6-tetraallyl glycoluril, triallyl isocyanurate, diallyl monoglycidyl isocyanurate, diallyl monomethyl isocyanurate, diallyl isocyanurate, triallyl trimellitate, and triallyl orthoformate.

[0061] Examples of the polymerizable crosslinking agent having a vinyl group include a polyvinylbenzyl compound and a polyvinylbenzyl ether compound.

[0062] The polymerizable crosslinking agent having an allyl group or a vinyl group may contain at least one selected from the group consisting of 1,3,4,6-tetraallyl glycoluril, triallyl isocyanurate, diallyl isocyanurate, and a polyvinyl benzyl ether compound from the viewpoint of dielectric properties and microprocessability, and may contain 1,3,4,6-tetraallyl glycoluril from the viewpoint of dielectric properties.

[0063] From the viewpoint of photocurability and low dielectric properties, the content of the crosslinking agent may be 0.1 to 20 parts by mass, 0.5 to 15 parts by mass, or 1 to 10 parts by mass, relative to 100 parts by mass of the total amount of the (A) component and the (B) component.

[0064] (Thermal Polymerization Initiator) The photosensitive resin composition according to this embodiment may further contain a thermal polymerization initiator from the viewpoint of promoting the polymerization reaction of the thermally polymerizable crosslinking agent. The thermal polymerization initiator is preferably a compound that decomposes upon heating during curing to generate radicals and promotes the polymerization reaction between the thermally polymerizable crosslinking agent and component (A) or component (B). Examples of the thermal polymerization initiator include organic peroxides.

[0065] Examples of organic peroxides include methyl ethyl ketone peroxide, methylcyclohexanone peroxide, methylacetoacetate peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(4,4-di-t- butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)cyclododecane, n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)-2-methylcyclohexane, t-butyl hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t-hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl 2,5-bis(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy)diisopropylbenzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, cinnamic acid peroxide, m-toluoyl peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, α,α'-bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butyl Examples of peroxymaleic acid include peroxymaleic acid, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxy-m-toluoyl benzoate, t-butylperoxybenzoate, bis(t-butylperoxy)isophthalate, t-butylperoxyallyl monocarbonate, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone.

[0066] The content of the thermal polymerization initiator is not particularly limited, but may be 0.1 to 10.0 parts by mass, 0.5 to 5.0 parts by mass, or 0.7 to 3.0 parts by mass relative to 100 parts by mass of the total amount of the component (A), the component (B), and the crosslinking agent.

[0067] The preparation means, conditions, etc. of the photosensitive resin composition are not particularly limited. For example, a method may be used in which predetermined amounts of various components are thoroughly and uniformly stirred and mixed using a mixer or the like, and then kneaded using a mixing roll, an extruder, a kneader, a roll, an extruder, etc. The kneading method is not particularly limited.

[0068] From the viewpoint of coatability, the viscosity of the photosensitive resin composition according to this embodiment at 25°C may be 400 to 4000 mPa·s, 400 to 3000 mPa·s, or 500 to 2000 mPa·s. The viscosity of the photosensitive resin composition at 25°C can be measured by the method described in the examples.

[0069] The dielectric constant at 10 GHz of the cured product of the photosensitive resin composition according to this embodiment may be 2.80 or less, 2.75 or less, or 2.70 or less. The dielectric loss tangent at 10 GHz of the cured product of the photosensitive resin composition may be 0.0060 or less, 0.0050 or less, 0.0045 or less, or 0.0040 or less. The dielectric constant and dielectric loss tangent can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0070] From the viewpoint of low warpage, the elastic modulus at 20°C of the cured product of the photosensitive resin composition according to this embodiment may be 50 to 1500 MPa, 100 to 1000 MPa, or 150 to 700 MPa. The elastic modulus at 20°C can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0071] From the viewpoint of heat resistance, the glass transition temperature (Tg) of the cured product of the photosensitive resin composition according to this embodiment may be 0 to 200° C., 10 to 150° C., or 20 to 100° C. Tg can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0072] The coefficient of linear expansion (CTE) of the cured product of the photosensitive resin composition according to this embodiment may be 50 to 200 ppm / °C, 60 to 180 ppm / °C, or 70 to 160 ppm / °C, from the viewpoints of low warpage and reliability. The CTE can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0073] From the viewpoint of heat resistance, the 5% weight loss temperature of the cured product of the photosensitive resin composition according to this embodiment may be 300 to 500° C., 320 to 450° C., or 340 to 420° C. The 5% weight loss temperature can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0074] From the viewpoint of reliability, the elongation at break of the cured product of the photosensitive resin composition according to this embodiment may be 50 to 250%, 70 to 200%, or 80 to 160%. The elongation at break can be measured using a cured film of the photosensitive resin composition by the method described in the examples.

[0075] The photosensitive resin composition according to this embodiment can form a thick insulating film having via holes, improve the smoothness of the coating surface when a thick coating film is formed, and can also improve the via opening property when a thick insulating film is formed. Furthermore, the photosensitive resin composition according to this embodiment can form an insulating film that exhibits low dielectric properties and excellent insulation reliability. The photosensitive resin composition according to this embodiment can be used to fabricate a semiconductor element having an interlayer insulating layer formed from a cured product of the photosensitive resin composition, and an electronic device including the semiconductor element.

[0076] The semiconductor element may be, for example, a memory, a package, or the like having a multilayer wiring structure, a rewiring structure, or the like. Examples of electronic devices include mobile phones, smartphones, tablet terminals, personal computers, and hard disk suspensions. By providing an insulating film formed from the photosensitive resin composition of this embodiment, semiconductor elements and electronic devices with excellent reliability can be provided. Semiconductor elements and electronic devices having a rewiring layer including an insulating film made of a cured product of the photosensitive resin composition of this embodiment are suitable as semiconductor elements and electronic devices for automotive use.

[0077] [Method for forming insulating film] An insulating film having via holes can be formed by photolithography. That is, the method for forming an insulating film according to this embodiment includes the steps of applying a photosensitive resin composition to a substrate and drying it to form a photosensitive layer, and exposing and developing the photosensitive layer to form an insulating film having via holes. The method for forming an insulating film according to this embodiment may also include the step of further heating and curing the photosensitive layer after exposure and / or development. Each step will be described in more detail below.

[0078] First, the photosensitive resin composition of the present embodiment is applied to a substrate and dried to form a photosensitive layer. In this process, a glass substrate, a semiconductor, a metal oxide insulator (e.g., TiO ２ , SiO ２ The photosensitive resin composition of the present embodiment is spin-coated onto a substrate such as a silicon nitride substrate, a silicon substrate, or a copper substrate using a spin coater or the like to form a coating film. By using the photosensitive resin composition of the present embodiment, a thick coating film with excellent smoothness can be formed by spin coating.

[0079] The substrate on which the coating film has been formed is dried using a hot plate, oven, or the like. There are no particular restrictions on the drying temperature or drying time, but drying at 80 to 150°C for 3 to 30 minutes is suitable. This results in the formation of a photosensitive layer on the substrate. The thickness of the photosensitive layer may be 15 μm or more, 20 to 50 μm, or 20 to 40 μm.

[0080] Next, the photosensitive layer is exposed to actinic rays in a pattern so that via holes are formed in the photosensitive layer after development, and the exposed areas are photocured. The exposure of the photosensitive layer can be carried out using a known projection exposure method, contact exposure method, direct writing exposure method, etc.

[0081] The light source for actinic rays is not particularly limited as long as it is a commonly used, well-known light source. For example, those that effectively emit ultraviolet light, such as carbon arc lamps, mercury vapor arc lamps, ultra-high pressure mercury lamps, high-pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid-state lasers such as YAG lasers, and semiconductor lasers such as gallium nitride blue-violet lasers, can be used. Also, those that effectively emit visible light, such as photographic flood lamps and sun lamps, can be used. Among these, from the viewpoint of further improving via opening properties, light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm, light sources capable of emitting monochromatic h-line light with an exposure wavelength of 405 nm, or light sources capable of emitting actinic rays with exposure wavelengths that are crossed by i, h, and g may be used. In particular, light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm may be used. Examples of light sources capable of emitting monochromatic i-line light with an exposure wavelength of 365 nm include ultra-high pressure mercury lamps.

[0082] After exposure, the unexposed portions of the photosensitive layer can be removed with a developer to form an insulating film having via holes. Suitable examples of the developer include aqueous alkali solutions such as sodium carbonate, sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH), as well as organic solvents such as cyclopentanone, cyclohexanone, and propylene glycol monomethyl ether acetate (PGMEA). Development using a developer can be performed by shower development, spray development, immersion development, paddle development, or the like.

[0083] By the above method, an insulating film made of a cured product of the photosensitive resin composition of this embodiment can be formed. The thickness of the insulating film may be 15 μm or more, 20 to 50 μm, or 20 to 40 μm. By using the photosensitive resin composition of this embodiment, excellent via opening properties can be obtained even when a thick insulating film having the above thickness is formed. Furthermore, by using the photosensitive resin composition of this embodiment to form a redistribution layer including a thick insulating film having the above thickness, the high-frequency characteristics of a semiconductor device including this redistribution layer can be improved.

[0084] From the viewpoint of increasing the density of the semiconductor package, the diameter (opening diameter) of the via hole in the insulating film may be 5 to 150 μm, 10 to 100 μm, or 20 to 60 μm. By using the photosensitive resin composition of this embodiment, excellent via opening properties can be obtained even when a via hole having the above diameter is formed.

[0085] The aspect ratio (thickness of insulating film / diameter of via hole) obtained by dividing the thickness of the insulating film by the diameter of the via hole provided in the insulating film may be 0.30 to 1.50, 0.40 to 1.40, or 0.50 to 1.20. By using the photosensitive resin composition of this embodiment, excellent via opening properties can be obtained even when a via hole with a large aspect ratio is formed.

[0086] The present disclosure will be specifically described below with reference to examples and comparative examples, but the present disclosure is not limited thereto. In each example, parts and percentages are by mass unless otherwise specified.

[0087] <Measurement Method> (Weight Average Molecular Weight) The weight average molecular weight (Mw) of the bismaleimide resin was measured by gel permeation chromatography (GPC). A sample prepared by dissolving the bismaleimide resin in tetrahydrofuran (THF) to a concentration of 3% by mass was poured into a column (GL-R420 x 1, GL-R430 x 1, GL-R440 x 1 (all manufactured by Hitachi High-Tech Fielding Corporation)) heated to 30 ° C., and 50 μL was injected. Measurements were carried out using THF as the developing solvent at a flow rate of 1.6 mL / min. The detector used was an L-3350 RI detector (manufactured by Hitachi, Ltd.), and the weight average molecular weight (Mw) was calculated from the elution time using a molecular weight / elution time curve created using standard polystyrene (manufactured by Tosoh Corporation).

[0088] (Non-volatile component (N.V.)) 0.75 g±0.25 g of the bismaleimide resin solution or photosensitive resin composition was weighed out using a precision balance and placed in an aluminum dish, and then dried in a hot air dryer at 150°C for 0.5 hours, and the non-volatile component (N.V.) was calculated using the following formula. The results are shown in Table 1. N.V. (mass %)={(W3-W1) / W2}×100 W1: mass (g) of empty aluminum dish W2: mass (g) of the bismaleimide resin solution or photosensitive resin composition before drying W3: mass (g) of the aluminum dish + remaining bismaleimide resin or photosensitive resin composition after drying

[0089] (Viscosity) The viscosity of the photosensitive resin composition was measured using an E-type viscometer (product name "RE85R", manufactured by Toki Sangyo Co., Ltd.). The measurement conditions were a sample amount of 1.0 mL, a measurement temperature of 25.0°C, a preheat time of 2 minutes, and a measurement time of 3 minutes. The results are shown in Table 1.

[0090] <Synthesis of Maleimide Resin> (Synthesis Example 1) Into a 1 L flask equipped with a condenser, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, 54.68 parts by mass of pyromellitic anhydride (manufactured by Daicel Corporation), 432.92 parts by mass of T-SOL100 (trade name, Solvent Naphtha, manufactured by ENEOS Corporation), and 94.78 parts by mass of Solmix A-11 (trade name, manufactured by Japan Alcohol Sales Co., Ltd., an alcohol-based solvent based on ethanol) were added. After addition, the temperature was raised to 80 ° C. and kept at 80 ° C. for 0.5 hours, and 179.46 parts by mass of dimer diamine (trade name "PRIAMINE 1075", manufactured by Croda Japan Co., Ltd.) was added dropwise. After dropwise addition, the mixture was kept at 80 ° C. for 0.5 hours, and then 6.42 parts by mass of an aqueous methanesulfonic acid solution (70% by mass aqueous solution, trade name "Lutropur MSA", manufactured by BASF) was added. The pressure in the reaction vessel was then reduced from atmospheric pressure by 0.03 MPa, and the temperature was raised to 160 ° C. while removing the alcohol-based solvent from the reaction solution. After the temperature was raised, a dehydration ring-closing reaction was carried out at 160 ° C. for 2 hours, and the water and alcohol-based solvent from the reaction solution were removed, resulting in a solution containing an intermediate polyimide resin. Next, the pressure in the reaction vessel was returned to atmospheric pressure, and the solution containing the obtained polyimide resin was cooled to 130 ° C., and 24.58 parts by mass of maleic anhydride (manufactured by Fuso Chemical Co., Ltd.) was added. The pressure in the reaction vessel was then reduced from atmospheric pressure by 0.03 MPa, and the temperature was raised to 160 ° C. After the temperature was raised, a dehydration ring-closing reaction was carried out at 160 ° C. for 4 hours, and the water in the reaction solution was removed, resulting in a solution containing a bismaleimide resin.

[0091] The resulting solution containing bismaleimide resin was placed in a separatory funnel, and 1,200 parts by mass of pure water was added. The separatory funnel was shaken and allowed to stand. After standing, the organic and aqueous layers were separated, and only the organic layer was recovered. The recovered organic layer was placed in a 1 L glass vessel equipped with a condenser, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, heated to 88-93°C, and water was removed. The vessel was then heated to 100°C and the solvent was partially removed for 0.5 hours under reduced pressure of 0.1 MPa from atmospheric pressure, yielding a solution of bismaleimide resin (A-1). The Mw of the bismaleimide resin (A-1) was 17,300, and N.V. was 56.0% by mass. The organic solvent contained in the bismaleimide resin (A-1) solution was T-SOL100 (solvent naphtha).

[0092] (Synthesis Example 2) A 2L pressure-resistant SUS container (manufactured by Todoroki Sangyo Co., Ltd.) equipped with a cooling tube, a separation tank, a nitrogen inlet tube, a thermocouple, and a stirrer, and equipped with equipment capable of carrying out a reaction under pressure while refluxing the solvent, was charged with 111 parts by mass of pyromellitic dianhydride (manufactured by Daicel Corporation), 907 parts by mass of toluene (manufactured by Wako Pure Chemical Industries, Ltd.), and 200 parts by mass of methanol (manufactured by Daishin Chemical Co., Ltd.). Next, nitrogen gas was introduced into the container and pressurized to a gauge pressure of 250 kPa, and then the temperature was raised to 80 ° C. and maintained at that temperature for 0.5 hours. Subsequently, 368 parts by mass of dimer diamine (trade name "PRIAMINE 1075", manufactured by Croda Japan Co., Ltd.) was added dropwise at a drop rate of 12.3 g / min. After the dropwise addition, the mixture was maintained at 80 ° C. for 0.5 hours, and then 6.5 parts by mass of methanesulfonic acid was added. Then, the reaction mixture was heated to 160 ° C. while removing the alcohol-based solvent from the reaction solution. After heating, a dehydration ring-closing reaction was carried out at 160°C for 2 hours, and water and alcohol solvents were removed from the reaction solution to obtain a solution containing an intermediate polyimide resin. Subsequently, the resulting polyimide resin-containing solution was cooled to 130°C, and 50 parts by mass of maleic anhydride (manufactured by Fuso Chemical Co., Ltd.) was added. The temperature was then raised to 160°C. After heating, a dehydration ring-closing reaction was carried out at 160°C for 4 hours, and water was removed from the reaction solution to obtain a solution containing a bismaleimide resin. Subsequent purification was carried out in the same manner as in Synthesis Example 1 to obtain a solution of bismaleimide resin (A-2). The Mw of the bismaleimide resin (A-2) was 16,700, and N.V. = 56.0% by mass. The organic solvent contained in the bismaleimide resin (A-2) solution was toluene.

[0093] Examples 1 to 4 and Comparative Examples 1 and 2 Preparation of Photosensitive Resin Composition and Cured Sheet Photosensitive resin compositions were prepared by blending the components shown below in the compositions (unit: parts by mass) shown in Table 1. Next, using an applicator, the photosensitive resin composition was applied to a Film Vina (registered trademark) film (PET film, manufactured by Fujimori Kogyo Co., Ltd., product name "NS14", film thickness 75 μm) so that the thickness after drying would be 50 μm, and the composition was dried in a dryer at 130°C for 10 minutes. Subsequently, using a UV irradiator (a UV irradiator with a conveyor, manufactured by GS Yuasa Corporation, using a metal halide lamp (MAL 500NAL)), the composition was irradiated with an accumulated light dose of 3000 mJ / cm.２ After UV irradiation, the composition was cured in a nitrogen dryer at 180° C. for 10 minutes to prepare a cured sheet.

[0094] Component (A): Maleimide resin Bismaleimide resins (A-1) and (A-2) prepared in Synthesis Examples 1 and 2 above Component (B): (meth)acrylic monomer (B-1) A-DCP (trade name: tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) (B-2) IBXA (trade name: isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Ltd.) Component (C): Photopolymerization initiator (C-1) Omnirad 819 (trade name: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, manufactured by IGM Resins B.V.) Component (D): Organic solvent (D-1) T-SOL100 (trade name: solvent naphtha, manufactured by ENEOS Corporation, boiling point 154 to 181°C) (D-2) Toluene (manufactured by Yamaichi Chemical Industry Co., Ltd., boiling point 110°C) Component (E): Coupling agent (E-1) KBM-503 (trade name, 3-methacryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Silicones Co., Ltd.) Component (F): Polymerization inhibitor (F-1) TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0095] [Evaluation of photosensitive properties] <Appearance after coating and film thickness after coating> The photosensitive resin composition was applied to a silicon wafer (12 inches) using a spin coater so that the film thickness after drying would be 25 μm. The appearance of the coating film after coating was visually observed and rated according to the following criteria. The coating film was then dried on a hot plate at 130° C. for 10 minutes and cooled to room temperature to form a photosensitive layer. The film thickness of the photosensitive layer was measured with a film thickness meter. The results are shown in Table 1. (Criteria for judging appearance after coating) A: No holes or irregularities were observed on the surface of the coating film, and the film had good smoothness. B: Holes or irregularities were observed on the surface of the coating film, and the film had poor smoothness.

[0096] <Appearance after development and via opening property> The photosensitive resin composition was applied to a Cu-sputtered silicon wafer (12 inches) using a spin coater so that the film thickness after drying would be 25 μm. After application, the coating film was dried for 10 minutes on a hot plate at 130°C or 100°C (Table 1, "Drying temperature after application [°C]") to form a photosensitive layer. The obtained photosensitive layer was exposed to an i-line stepper exposure machine (manufactured by Therma Precision Co., Ltd., product name "Stepper-NMS-Sc6k") and a negative pattern mask with via diameters of 100, 80, 60, 40, 35, 30, and 25 μm, with an accumulated light dose of 3000 mJ / cm. ２ UV irradiation was performed under the following conditions. After UV irradiation, the film was heated on a hot plate at 80°C for 3 minutes. After the heat treatment, a paddle-type developing device (manufactured by Mikasa Co., Ltd., product name "AD-3000") was used to perform development twice with cyclopentanone at room temperature for 25 seconds, followed by a 10-second rinse with PGMEA (propylene glycol monomethyl ether acetate) once, and air-drying at 3000 rpm to obtain a developed patterned cured film (insulating film). The appearance of the resulting patterned cured film (presence or absence of peeling) was visually observed and evaluated according to the following criteria. The film thickness of the patterned cured film was also measured with a film thickness meter. Furthermore, the via opening property of the patterned cured film was determined by observation with a metallurgical microscope as the smallest via diameter that was open and free of residue at the via bottom. The results are shown in Table 1. Note that a via opening property result of ">100" means that even vias with a diameter of 100 μm were not opened without residue. For the patterned cured film in which vias were opened without residue, the aspect ratio obtained by dividing the thickness of the patterned cured film by the diameter of the smallest via that was opened without residue is shown in Table 1. (Criteria for evaluating appearance after development) A: No peeling of the patterned cured film B: Peeling in part of the patterned cured film C: Peeling over the entire surface of the patterned cured film

[0097] [Evaluation of Cured Product Properties] <Dielectric Properties> A test specimen measuring 50 mm x 100 mm was prepared using the cured sheet. Using this test specimen, the relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz were measured at room temperature (20°C) using a network analyzer (manufactured by KEYSIGHT Technologies, product name "P5003A") and a split cylinder resonator (manufactured by KEYSIGHT Technologies). The results are shown in Table 2.

[0098] <Elastic Modulus and Tg> Test pieces measuring 20 mm x 10 mm were prepared using the cured sheets, and the elastic modulus at 20°C and Tg (tan δ peak) were measured using a dynamic viscoelasticity measuring device (manufactured by SII NanoTechnology Inc., product name "DMS6100") under conditions of a frequency of 1 Hz, a measurement temperature of -40°C to 220°C, and a heating rate of 10°C / min. The results are shown in Table 2. For samples with two tan δ peaks, the two peak temperatures (i) and (ii) are shown as Tg in Table 2.

[0099] <Coefficient of Linear Expansion (CTE)> A test specimen measuring 30 mm x 4 mm was prepared from the cured sheet. Using this test specimen, the coefficient of linear expansion (CTE) was measured using a thermomechanical analyzer (manufactured by Hitachi High-Tech Science Corporation, product name "TMA / SS7100"). The measurement mode was tensile mode, the measurement load was 5 mN, the measurement atmosphere was air, the heating rate was 5°C / min, and the measurement temperature range was -50 to 250°C. The measurement result from the second run at -20°C to 40°C was taken as the CTE. The results are shown in Table 2.

[0100] <5% Weight Loss Temperature> 6.0 to 10.0 mg of the cured sheet was weighed out and placed in an open-type sample container (manufactured by Seiko Denshi Co., Ltd., product name "P / N SSC000E030"), and the 5% weight loss temperature (T ｄ５ The measurement device used was a TG / DTA7200 (manufactured by Hitachi High-Tech Science Corporation). The results are shown in Table 2.

[0101] <Elongation at break> A test specimen measuring 50 mm x 10 mm was prepared from the cured sheet. This test specimen was used in an autograph (manufactured by Shimadzu Corporation, product name "AGS-X"), with each end of the test specimen fixed to the axis at 10 mm, and the elongation at break was measured at a measurement temperature of 25°C and a tensile speed of 10 mm / min. The results are shown in Table 2.

[0102]

[0103]

Claims

1. A photosensitive resin composition comprising a maleimide resin, a (meth)acrylic monomer, a photopolymerization initiator, and an organic solvent, wherein the maleimide resin is a reaction product of a tetracarboxylic dianhydride (a1), an amine (a2), and maleic anhydride (a3), the amine (a2) comprises a dimer diamine, the (meth)acrylic monomer comprises a bifunctional (meth)acrylic monomer, and the organic solvent comprises a high boiling point solvent having a boiling point of 150 to 200°C.

2. The photosensitive resin composition according to claim 1, wherein the non-volatile component is 45 to 70% by mass.

3. The photosensitive resin composition according to claim 1, having a viscosity at 25° C. of 400 to 4,000 mPa·s.

4. A cured product of the photosensitive resin composition according to any one of claims 1 to 3.

5. A semiconductor device comprising a rewiring layer including an insulating film made of a cured product of the photosensitive resin composition according to any one of claims 1 to 3.

6. The semiconductor device according to claim 5, wherein the insulating film has a thickness of 15 μm or more.

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