Sealing resin composition and semiconductor device

Abstract

A sealing resin composition containing an epoxy resin and a curing accelerator, wherein the curing accelerator content is 1-10 mass% relative to the epoxy resin.

Description

Encapsulating resin composition and semiconductor device

[0001] This disclosure relates to a encapsulating resin composition and a semiconductor device.

[0002] Various semiconductor elements used in electronic components such as transistors and ICs (Integrated Circuits) are predominantly sealed with resin due to factors such as productivity and manufacturing cost. Resin compositions are widely used as sealing materials. This is because epoxy resins offer an excellent balance of various properties required for sealing materials, including workability, moldability, electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesion to inserts.

[0003] Patent Document 1 describes an epoxy resin composition for semiconductor encapsulation that is excellent in fluidity, release properties, and continuous moldability, and includes (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, (E2) a glycerin trifatty acid ester, (F) a silane coupling agent, and (G) a compound in which hydroxyl groups are bonded to two or more adjacent carbon atoms constituting an aromatic ring.

[0004] Patent No. 5605394

[0005] In large semiconductor devices such as power semiconductors, delamination is likely to occur internally during reliability testing due to differences in the coefficients of thermal expansion of the components. To suppress this delamination, it is desirable to control the warpage of the semiconductor device, and for this purpose, it is required that the molding shrinkage rate of the cured product of the encapsulating resin composition can be reduced.

[0006] In view of the above circumstances, the present disclosure aims to provide a encapsulating resin composition capable of producing a cured product with reduced molding shrinkage, and a semiconductor device using the same.

[0007] Means for solving the above problems include the following embodiments: <1> A sealing resin composition comprising an epoxy resin and a curing accelerator, wherein the content of the curing accelerator is 1% by mass to 10% by mass with respect to the epoxy resin. <2> The sealing resin composition according to <1>, further comprising an aromatic ring and two or more hydroxyl groups bonded to adjacent positions of the aromatic ring, or a hydroxyl group and one or more methoxy groups. <3> The sealing resin composition according to <2>, wherein the hydroxyl group-containing compound comprises a benzene ring or a naphthalene ring. <4> The sealing resin composition according to either <2> or <3>, wherein the content of the hydroxyl group-containing compound is 0.5% by mass to 10% by mass with respect to the epoxy resin. <5> The sealing resin composition according to any one of <1> to <4>, wherein the curing accelerator comprises an imidazole compound. <6> The sealing resin composition according to any one of <1> to <5>, further comprising a phenol curing agent. <7> A encapsulation resin composition according to any one of <1> to <6> for encapsulating power semiconductors. <8> A semiconductor device comprising: a semiconductor chip; a lead frame on which the semiconductor chip is mounted; and a cured product of the encapsulation resin composition according to any one of <1> to <6> for encapsulating the semiconductor chip.

[0008] This disclosure provides a encapsulating resin composition capable of producing a cured product with reduced molding shrinkage, and a semiconductor device using the same.

[0009] This is a schematic cross-sectional view showing an example of the configuration of a semiconductor device in this disclosure.

[0010] The embodiments for carrying out the present invention will be described in detail below. However, the embodiments of this disclosure are not limited to the following embodiments. In the following embodiments, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the embodiments of this disclosure.

[0011] In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, provided that the purpose of the process is achieved. In this disclosure, numerical ranges indicated using "~" include the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced by the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0012] In this disclosure, unless otherwise specified, the number of carbon atoms in an organic group refers to the number of carbon atoms including those of substituents if the organic group includes substituents.

[0013] ≪Sealing Resin Composition≫ The sealing resin composition of this disclosure (hereinafter also referred to as the "resin composition") comprises an epoxy resin and a curing accelerator, wherein the content of the curing accelerator is 1% to 10% by mass relative to the epoxy resin. The resin composition of this disclosure makes it possible to produce a cured product with reduced molding shrinkage. When the amount of curing accelerator acting as a catalyst is large relative to the epoxy resin, the crosslinking structure tends to become disordered, and the curing reaction is completed with a larger free volume remaining depending on the amount of curing accelerator added. It is presumed that this effect makes it possible to reduce the molding shrinkage of the cured product.

[0014] The resin composition is used for encapsulating devices and may also be used for encapsulating power semiconductors. Power semiconductors are large semiconductor devices, and delamination is likely to occur internally during reliability testing due to differences in the coefficients of thermal expansion of the components. By reducing the molding shrinkage rate of the cured product of the encapsulating resin composition, the warping of the semiconductor device can be adjusted, and as a result, delamination of the cured product tends to be suppressed.

[0015] The components that may be included in the resin composition of this disclosure are described in detail below.

[0016] <Epoxy Resin> The resin composition contains an epoxy resin. The type of epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule. The epoxy resin may be solid or liquid at 25°C and atmospheric pressure, but it is preferably solid. Specifically, novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) are obtained by condensing or co-condensing a novolac resin (phenol novolac-type epoxy resin, orthocresol novolac-type epoxy resin, etc.) obtained by condensing or co-condensing a novolac resin (phenol novolac-type epoxy resin, orthocresol novolac-type epoxy resin, etc.) with at least one phenolic compound selected from the group consisting of phenol compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene) under an acidic catalyst; triphenylmethane-type epoxy resins are obtained by condensing or co-condensing a triphenylmethane-type phenolic resin (phenol novolac-type epoxy resin, orthocresol novolac-type epoxy resin, etc.) with the above phenolic compound and naphthol compound and aldehyde compound under an acidic catalyst. Copolymer epoxy resins are obtained by epoxidizing novolac resins obtained by co-condensation; diphenylmethane type epoxy resins are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl type epoxy resins are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene type epoxy resins are diglycidyl ethers of stilbene-based phenol compounds; sulfur atom-containing epoxy resins are diglycidyl ethers of bisphenol S, etc.; glycidyl ether type epoxy resins are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester type epoxy resins are glycidyl esters of polycarboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine type epoxy resins are obtained by substituting active hydrogen bonded to nitrogen atoms with glycidyl groups, such as aniline, diaminodiphenylmethane, and isocyanuric acid.Dicyclopentadiene-type epoxy resins are epoxidized resins of a co-condensation of dicyclopentadiene and phenol compounds; alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, in which the intramolecular olefin bond is epoxidized; paraxylylene-modified epoxy resins are glycidyl ethers of paraxylylene-modified phenol resins; metaxylylene-modified epoxy resins are glycidyl ethers of metaxylylene-modified phenol resins; terpene-modified epoxy resins are glycidyl ethers of terpene-modified phenol resins; dicyclopentadiene Examples of epoxy resins include dicyclopentadiene-modified epoxy resins, which are glycidyl ethers of phenol-modified resins; cyclopentadiene-modified epoxy resins, which are glycidyl ethers of cyclopentadiene-modified phenol resins; polycyclic aromatic ring-modified epoxy resins, which are glycidyl ethers of polycyclic aromatic ring-modified phenol resins; naphthalene-type epoxy resins, which are glycidyl ethers of naphthalene ring-containing phenol resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; and aralkyl-type epoxy resins, which are epoxidized aralkyl-type phenol resins such as phenol aralkyl resins and naphthol aralkyl resins. Furthermore, epoxides of silicone resins and acrylic resins can also be cited as epoxy resins. These epoxy resins may be used individually or in combination of two or more types.

[0017] Among the epoxy resins mentioned above, epoxy resins selected from the group consisting of biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur atom-containing epoxy resins, novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenylmethane-type epoxy resins, copolymer-type epoxy resins, and aralkyl-type epoxy resins (collectively referred to as "specific epoxy resin 1") are preferred from the viewpoint of balancing temperature cycle resistance and fluidity. Specific epoxy resin 1 may be used alone or in combination of two or more types.

[0018] As an example, the epoxy resin may be at least one (preferably two or more) epoxy resins selected from the group consisting of triphenylmethane-type epoxy resins, bisphenol-type epoxy resins (for example, bisphenol-type epoxy resins having an imide structure in the molecule), and naphthalene-type epoxy resins (hereinafter also referred to as "specific epoxy resin 2"). The triphenylmethane-type epoxy resin, bisphenol-type epoxy resin, and naphthalene-type epoxy resin may each be one or more independent types. The triphenylmethane-type epoxy resin may be an epoxy resin that does not contain aromatic rings other than the triphenylmethane skeleton, or it may be an epoxy resin that contains aromatic rings other than the triphenylmethane skeleton. Examples of epoxy resins containing aromatic rings other than the triphenylmethane skeleton include compounds represented by the following chemical formulas.

[0019]

[0020] When the epoxy resin contains a specific epoxy resin (meaning specific epoxy resin 1 or specific epoxy resin 2; the same applies hereinafter), from the viewpoint of exhibiting the performance of the specific epoxy resin, it is preferable that the total content of the specific epoxy resin is 30% by mass or more of the total epoxy resin, and more preferably 50% by mass or more. The total content of the specific epoxy resin is not particularly limited as long as it is 100% by mass or less of the total epoxy resin.

[0021] The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoint of balancing various properties such as moldability, temperature cycle resistance, and electrical reliability, the epoxy equivalent of the epoxy resin is preferably 100 g / eq to 1000 g / eq, more preferably 150 g / eq to 500 g / eq, and even more preferably 160 g / eq to 300 g / eq. The epoxy equivalent of the epoxy resin shall be the value measured by the method in accordance with JIS K 7236:2009.

[0022] When the epoxy resin is solid, its softening point or melting point is not particularly limited. From the viewpoint of moldability and temperature cycle resistance, it is preferably 40°C to 180°C, and from the viewpoint of ease of handling during the preparation of the resin composition, it is more preferably 50°C to 130°C. The melting point of the epoxy resin shall be the value measured by differential scanning calorimetry (DSC), and the softening point of the epoxy resin shall be the value measured by the method (ring-sphere method) in accordance with JIS K 7234:1986.

[0023] The epoxy resin content in the resin composition is preferably 0.5% to 50% by mass, and more preferably 2% to 30% by mass, from the viewpoint of strength, fluidity, heat resistance, moldability, etc.

[0024] <Phenol curing agent> The resin composition may contain a phenol curing agent. Examples of phenol curing agents include phenol resins and polyhydric phenol compounds having two or more phenolic hydroxyl groups in one molecule. The phenol curing agent may be solid or liquid at 25°C and atmospheric pressure, but it is preferably solid. Specifically, a novolac-type phenolic resin obtained by condensing or co-condensing the above phenolic compound with polyhydric phenol compounds such as resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; at least one phenolic compound selected from the group consisting of phenol compounds such as phenol, m-cresol, p-cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, and an aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde under an acidic catalyst; and the above phenolic compound with dimethoxyp-xylene, bis(methoxymethyl)biphenyl, etc. Examples include aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins; paraxylylene and / or metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above phenolic compounds and dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins such as biphenyl aralkyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensation or co-condensation of the above phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenolic curing agents may be used individually or in combination of two or more.

[0025] Among phenol curing agents, at least one selected from the group consisting of aralkyl-type phenol resins, dicyclopentadiene-type phenol resins, triphenylmethane-type phenol resins, copolymerized phenol resins of benzaldehyde-type phenol resins and aralkyl-type phenol resins, and novolac-type phenol resins (these are referred to as "specific phenol curing agents") is preferred from the viewpoint of temperature cycling resistance. Specific phenol curing agents may be used individually or in combination of two or more types.

[0026] In one embodiment, the phenol curing agent preferably contains an aralkyl-type phenol resin. The aralkyl-type phenol resin may be used in combination with other phenol curing agents. When the phenol resin contains an aralkyl-type phenol resin, the content of the aralkyl-type phenol resin may be 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total mass of the phenol curing agent. The content of the aralkyl-type phenol resin may be 100% by mass or less, based on the total mass of the phenol curing agent.

[0027] The following are specific examples of preferred phenol curing agents.

[0028] Examples of aralkyl-type phenolic resins include phenolic aralkyl resins synthesized from phenolic compounds and dimethoxyp-xylene, bis(methoxymethyl)biphenyl, etc., and naphthol aralkyl resins. Aalkyl-type phenolic resins may be further copolymerized with other phenolic resins. Examples of copolymerized aralkyl-type phenolic resins include copolymerized phenolic resins of benzaldehyde-type phenolic resin and aralkyl-type phenolic resin, copolymerized phenolic resins of salicylaldehyde-type phenolic resin and aralkyl-type phenolic resin, and copolymerized phenolic resins of novolac-type phenolic resin and aralkyl-type phenolic resin.

[0029] The aralkyl-type phenol resin is not particularly limited as long as it is a phenol resin synthesized from at least one selected from the group consisting of phenol compounds and naphthol compounds, and dimethoxyparaxylene, bis(methoxymethyl)biphenyl or derivatives thereof. For example, phenol resins represented by the following general formulas (XII) to (XIV) are preferred.

[0030]

[0031] In formulas (XII) to (XIV), R ２３ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and all of them may be the same or different. R ２２ , R ２４ , R ２５ and R ２８ each represent a monovalent organic group having 1 to 18 carbon atoms, and all of them may be the same or different. R ２６ and R ２７ each represent a hydroxyl group or a monovalent organic group having 1 to 18 carbon atoms, and all of them may be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, each k is independently an integer of 0 to 4, and each p is independently an integer of 0 to 4. n is an average value, and each is independently a number of 0 to 10.

[0032] Among the phenol resins represented by the above general formula (XII), MEH-7851 (a product name of Meiwa Kasei Co., Ltd.) wherein i is 0 and all R ２３ are hydrogen atoms is available as a commercial product.

[0033] Among the phenol resins represented by the above general formula (XIII), XL-225, XLC (product names of Mitsui Chemicals, Inc.), MEH-7800SS (a product name of Meiwa Kasei Co., Ltd.) wherein i is 0 and k is 0 are available as commercial products.

[0034] Among the phenol resins represented by the above general formula (XIV), SN-170 (a product name of Nippon Steel Chemical & Material Co., Ltd.) wherein j is 0, k is 0 and p is 0, and a compound wherein j is 0, k is 1 and R ２７Products such as SN-395 (Nippon Steel Chemical & Material Co., Ltd., product name), in which the group is a hydroxyl group and p is 0, are commercially available.

[0035] In the above general formulas (XII) to (XIV), R ２２ ~R ２８ The statement "they may all be the same or all different" refers, for example, to the i Rs in equation (XII). ２２ This means that all of them may be identical or mutually different. ２３ ~R ２８ Regarding this as well, it means that the number of each element included in the formula may all be the same or they may be different from each other. Also, R ２２ ~R ２８ These can be the same or different. For example, R ２２ and R ２３ All of them may be the same or different.

[0036] In the above general formulas (XII) to (XIV), n is preferably in the range of 0 to 10. If it is 10 or less, the melt viscosity of the resin component will not become too high, the viscosity of the resin composition during melt molding will also be low, and filling defects, deformation of bonding wires (gold wires connecting the element and lead) will be less likely to occur. The average n in one molecule is preferably set in the range of 0 to 4.

[0037] The hydroxyl group equivalent of the phenol curing agent is not particularly limited. From the viewpoint of balancing various properties such as moldability, temperature cycle resistance, and electrical reliability, it is preferably 70 g / eq to 1000 g / eq, and more preferably 80 g / eq to 500 g / eq.

[0038] The hydroxyl group equivalent of the phenol curing agent may be a value measured by, for example, a method in accordance with JIS K 0070:1992.

[0039] When the phenol curing agent is solid, its softening point or melting point is not particularly limited. From the viewpoint of moldability and temperature cycle resistance, it is preferably 40°C to 180°C, and from the viewpoint of ease of handling during the manufacture of the resin composition, it is more preferably 50°C to 130°C. Furthermore, from the viewpoint of improving fluidity and reducing the high-temperature modulus of the cured resin composition, thereby improving temperature cycle resistance, the softening point or melting point of the phenol curing agent is preferably 50°C to 100°C, and more preferably 50°C to 75°C.

[0040] The melting point or softening point of the curing agent shall be a value measured in the same manner as the melting point or softening point of the epoxy resin.

[0041] The equivalent ratio of epoxy resin to phenol curing agent, i.e., the ratio of hydroxyl groups in the phenol curing agent to the number of epoxy groups in the epoxy resin (number of hydroxyl groups in phenol curing agent / number of epoxy groups in epoxy resin), is not particularly limited. From the viewpoint of minimizing unreacted components, the equivalent ratio of epoxy resin to phenol curing agent is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the viewpoint of moldability and temperature cycle resistance, it is even more preferable that the equivalent ratio of epoxy resin to phenol curing agent is set in the range of 0.8 to 1.2.

[0042] In the resin composition of this disclosure, the content of the phenol curing agent may be 30 to 100 parts by mass, 40 to 80 parts by mass, 50 to 70 parts by mass, or 50 to 60 parts by mass per 100 parts by mass of epoxy resin.

[0043] The resin composition may contain a phenol curing agent in addition to a curing agent other than a phenol curing agent. The proportion of the phenol curing agent to the total amount of curing agent is preferably 80% by mass or more, and preferably 90% by mass or more. The proportion of the phenol curing agent to the total amount of curing agent may be 100% by mass or less.

[0044] <Curing Accelerator> The resin composition contains a curing accelerator. The type of curing accelerator is not particularly limited and can be selected according to the type of epoxy resin, the desired properties of the resin composition, etc. Examples of curing accelerators include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU); 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-ethyl-4-methylimidazole, and 2-heptadecylimidazole. Cyclic amidine compounds such as ru; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; these compounds include maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenoxy Compounds having intramolecular polarization obtained by adding quinone compounds such as yl-1,4-benzoquinone and compounds having π bonds, such as diazophenylmethane; cyclic amidinium compounds such as tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, tetraphenylborate salt of 2-ethyl-4-methylimidazole, and tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide;Organic phosphines such as primary phosphines like ethylphosphine and phenylphosphine, secondary phosphines like dimethylphosphine and diphenylphosphine, triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl-alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, trinaphthylphosphine, tris(benzyl)phosphine, and other tertiary phosphines; phosphine compounds such as complexes of the above organic phosphines with organoborons; and the above organic phosphines or the above phosphine compounds with maleic anhydride, 1,4-benzoquinone, 2,5-tholquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone. Compounds having intramolecular polarization obtained by adding compounds having π bonds, such as quinone compounds like 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, anthraquinone, and diazophenylmethane; and the organophosphine or the phosphine compound with 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, and 4-iodidepheno Compounds having intramolecular polarization obtained by reacting halogenated phenol compounds such as 3-iodidephenol, 2-iodidephenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-t-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, and 4-bromo-4'-hydroxybiphenyl, followed by a dehalogenation step;Examples include tetrasubstituted phosphonium compounds such as tetraphenylphosphonium, tetraphenylborate salts of tetrasubstituted phosphoniums such as tetraphenylphosphonium tetra-p-tolylborate, and salts of tetrasubstituted phosphonium with phenolic compounds; phosphobetaine compounds; and adducts of phosphonium compounds with silane compounds. The curing accelerator may be used alone or in combination of two or more types.

[0045] For example, the curing accelerator may contain imidazole compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-ethyl-4-methylimidazole, and 2-heptadecylimidazole.

[0046] The content of the curing accelerator is 1% to 10% by mass relative to the epoxy resin, and may be 1.5% to 8% by mass, 2% to 5% by mass, or 2% to 4% by mass.

[0047] <Specific Hydroxyl Group-Containing Compounds> The resin composition may contain an aromatic ring and two or more hydroxyl groups bonded to adjacent positions on the aromatic ring, or a hydroxyl group and one or more methoxy groups (specific hydroxyl group-containing compound). The number of hydroxyl groups bonded to the aromatic ring may be two or three or more. If the number of hydroxyl groups bonded to the aromatic ring is three or more, it is preferable that all three or more hydroxyl groups are bonded to adjacent positions on the aromatic ring. The specific hydroxyl group-containing compound may be a compound in which one or more hydroxyl groups and one or more methoxy groups are bonded to adjacent positions on the aromatic ring. The total number of hydroxyl groups and methoxy groups may be two or more, or three or four or more.

[0048] Certain hydroxyl group-containing compounds preferably contain a benzene ring or a naphthalene ring. The aromatic ring to which at least two hydroxyl groups are bonded is preferably a benzene ring or a naphthalene ring.

[0049] Examples of specific hydroxyl group-containing compounds include 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene, gallic acid, propyl gallate, o-methoxyphenol, 2-hydroxy-3-methoxynaphthalene, 2,3-dimethoxyphenol, and 2,6-dimethoxyphenol.

[0050] From the viewpoint of fluidity, the content of a specific hydroxyl group-containing compound relative to the total mass of the epoxy resin may be 0.3% by mass or more, 0.5% by mass or more, 1.0% by mass or more, 2.0% by mass or more, or 3.0% by mass or more. Furthermore, the content of a specific hydroxyl group-containing compound relative to the total mass of the epoxy resin may be 20.0% by mass or less, 17.5% by mass or less, 15.0% by mass or less, 12.5% ​​by mass or less, or 10.0% by mass or less. When the content of the specific hydroxyl group-containing compound is within the above range, the decrease in adhesiveness tends to be suppressed. For example, the content of a specific hydroxyl group-containing compound relative to the total mass of the epoxy resin may be 0.3% by mass to 20% by mass, or 0.5% by mass to 10% by mass. Furthermore, from the viewpoint of the molding shrinkage rate of the cured product, the content of a specific hydroxyl group-containing compound relative to the total mass of the epoxy resin may be 0.3% to 5% by mass, 0.5% to 3% by mass, or 0.8% to 2% by mass.

[0051] The content of the specific hydroxyl group-containing compound may be 0.05% to 10% by mass, 0.05% to 5% by mass, 0.05% to 3% by mass, or 0.05% to 2% by mass, based on the total amount of the sealing resin composition.

[0052] <Inorganic Fillers> The resin composition may contain inorganic fillers. The material of the inorganic filler is not particularly limited. Specific examples of inorganic filler materials include fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, magnesium oxide, silicon carbide, beryllia, zirconia, zircon, fossterite, steatite, spinel, mullite, titania, talc, clay, mica, and other inorganic materials. Inorganic fillers with flame-retardant properties may also be used. Examples of inorganic fillers with flame-retardant properties include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium-zinc hydroxide, and zinc borate. Among inorganic fillers, silica such as fused silica is preferred from the viewpoint of reducing the coefficient of thermal expansion, and alumina is preferred from the viewpoint of high thermal conductivity.

[0053] The shape of the inorganic filler is not particularly limited, but a spherical shape is preferred from the viewpoint of filling properties and mold wear resistance.

[0054] Inorganic fillers may be used individually or in combination of two or more types. "Using two or more inorganic fillers in combination" includes, for example, using two or more inorganic fillers with the same components but different average particle sizes, using two or more inorganic fillers with the same average particle size but different components, and using two or more inorganic fillers with different average particle sizes and types.

[0055] The content of inorganic fillers in the resin composition is not particularly limited. From the viewpoint of further improving properties such as the coefficient of thermal expansion, thermal conductivity, and elastic modulus of the cured product, the content of inorganic fillers is preferably 50 volume% or more of the total resin composition, more preferably 55 volume% or more, even more preferably 60 volume% or more, particularly preferably 65 volume% or more, and extremely preferably 70 volume% or more. From the viewpoint of improving fluidity and reducing viscosity, the content of inorganic fillers is preferably 99 volume% or less of the total resin composition, preferably 90 volume% or less, more preferably 85 volume% or less, and even more preferably 80 volume% or less.

[0056] The inorganic filler content in the cured resin composition is measured as follows: First, the total mass of the cured material is measured. The cured material is then fired at 400°C for 2 hours, and then at 700°C for 3 hours to evaporate the resin components, and the mass of the remaining inorganic filler is measured. The volume is calculated from the obtained masses and their respective specific gravities, and the ratio of the volume of inorganic filler to the total volume of the cured material is obtained as the inorganic filler content.

[0057] The mass-based content of inorganic fillers in the resin composition may be 70% by mass or more, 80% by mass or more, or 85% by mass or more. Furthermore, the mass-based content of inorganic fillers in the resin composition may be 95% by mass or less, 90% by mass or less, or 85% by mass or less.

[0058] When the inorganic filler is particulate, its average particle size is not particularly limited. For example, the overall volume-average particle size of the inorganic filler is preferably 80 μm or less, but may also be 50 μm or less, 40 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. Furthermore, the overall volume-average particle size of the inorganic filler is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. When the volume-average particle size of the inorganic filler is 0.1 μm or more, the increase in viscosity of the resin composition tends to be further suppressed. When the volume-average particle size is 80 μm or less, the ability to fill narrow gaps tends to be further improved. The volume-average particle size of the inorganic filler can be measured as the particle size (D50) when the cumulative amount from the small diameter side reaches 50% in the volume-based particle size distribution measured by a laser scattering diffraction particle size distribution analyzer.

[0059] <Various Additives> In addition to the components described above, the resin composition may also contain various additives such as coupling agents, ion exchangers, mold release agents, flame retardants, colorants, and stress relievers. The resin composition may also contain various additives known in the art, as needed, in addition to the additives exemplified below.

[0060] (Coupling Agent) If the resin composition contains an inorganic filler, a coupling agent may be included to improve the adhesion between the resin component and the inorganic filler. In this disclosure, nitrogen-containing compounds are not included as coupling agents. Examples of known coupling agents include silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, as well as titanium compounds, aluminum chelate compounds, and aluminum / zirconium compounds. In one embodiment, the resin composition is preferably made to include anilinosilane from the viewpoint of ease of handling.

[0061] When the resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass, per 100 parts by mass of the inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more per 100 parts by mass of the inorganic filler, the adhesion to the frame tends to improve further. When the amount of the coupling agent is 5 parts by mass or less per 100 parts by mass of the inorganic filler, the moldability of the package tends to improve further.

[0062] From the viewpoint of adhesion between the resin component and the inorganic filler, it is preferable that the resin composition contains a silane coupling agent. Generally, silane coupling agents tend to adsorb moisture, and depending on the type and content of the silane coupling agent, this may cause an increase in water absorption. On the other hand, it has been found that the resin composition of this disclosure has excellent moisture-absorbing curing properties even when it contains a silane coupling agent. From this viewpoint, when the resin composition contains a silane coupling agent, the content of the silane coupling agent may be 2.0% by mass or more, 3.0% by mass or more, or 3.5% by mass or more, based on the total mass of the resin component (for example, the total mass of the epoxy resin and the phenol curing agent). Furthermore, the content of the silane coupling agent may be 10.0% by mass or less, 8.0% by mass or less, or 6.0% by mass or less, based on the resin component.

[0063] (Ion exchanger) The resin composition may contain an ion exchanger. The ion exchanger is not particularly limited, and conventionally known ones can be used. Specifically, examples include hydrotalcite compounds and hydrated oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchanger may be used alone or in combination of two or more.

[0064] If the resin composition contains an ion exchanger, the amount is not particularly limited as long as it is sufficient to capture ions such as halogen ions. For example, it is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin component.

[0065] In particular, the resin composition preferably contains a hydrotalcite compound. The hydrotalcite compound has anion exchange ability and contains chloride ions (Cl) present in the resin composition. － ), formate ion (HCOO － ), acetate ion (CH ３ COO － It captures ionic impurities such as ) and others. In particular, hydrotalcite compounds capture chloride ions (Cl － It is considered that this material has high capture capacity and, when used in combination with nitrogen-containing compounds in resin compositions, can efficiently reduce ionic impurities and improve moisture resistance reliability.

[0066] Hydrotalcite compounds are complex salt compounds containing magnesium, aluminum, hydroxyl groups, carbonate groups, and any water of crystallization. Furthermore, compounds in which a portion of the magnesium or aluminum in the above complex salt compounds is replaced with metals such as alkali metals or zinc; and compounds in which the hydroxyl groups or carbonate groups are replaced with other anionic groups are also listed as hydrotalcite compounds. Among these, hydrotalcite represented by the following general formula (A) is preferred.

[0067] Mg （１－Ｘ） Al Ｘ (OH) ２ (CO ３ ) Ｘ／２ mH ２O ……(A) (0 < X ​​≤ 0.5, m is a positive number)

[0068] In equation (A), X is a positive number representing the amount of Mg substituted for Al, and it is preferable that 0.20 ≤ X ≤ 0.33. m represents a positive number greater than 0, and it is preferable that 0 < m ≤ 2.

[0069] The content of the hydrotalcite compound is not particularly limited. From the viewpoint of improving moisture resistance reliability, the content of the hydrotalcite compound is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and even more preferably 1.0 part by mass or more, per 100 parts by mass of epoxy resin. From the viewpoint of fully exhibiting the effects of other components, and from the viewpoint of suppressing the decrease in filling ability into narrow sections and wire flow due to viscosity increase, the content of the hydrotalcite compound is preferably 20.0 parts by mass or less, more preferably 15.0 parts by mass or less, and even more preferably 10.0 parts by mass or less, per 100 parts by mass of epoxy resin. From the above viewpoints, the content of the hydrotalcite compound is preferably 0.5 to 20.0 parts by mass, more preferably 0.8 to 15.0 parts by mass, and even more preferably 1.0 to 10.0 parts by mass, per 100 parts by mass of epoxy resin.

[0070] Furthermore, the hydrotalcite compound content may be 3.0 parts by mass or less, 2.0 parts by mass or less, or 1.5 parts by mass or less per 100 parts by mass of epoxy resin, from the viewpoint of fully exhibiting the effects of other components and from the viewpoint of suppressing the reduction in filling ability into narrow sections and wire flow due to thickening. In the resin compositions according to the first and second embodiments, ionic impurities can be suitably reduced even if the hydrotalcite content is kept within the above range. The hydrotalcite content may be 0.1 to 3.0 parts by mass, 0.2 to 2.0 parts by mass, or 0.3 to 1.5 parts by mass per 100 parts by mass of epoxy resin.

[0071] (Release Agent) The resin composition may contain a release agent from the viewpoint of obtaining good release properties from the mold during molding. The release agent is not particularly limited, and conventionally known ones can be used. Specifically, examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. The release agent may be used alone or in combination of two or more types.

[0072] If the resin composition contains a release agent, the amount is preferably 0.01 to 15 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the resin component. When the amount of release agent is 0.01 parts by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When it is 15 parts by mass or less, better adhesion tends to be obtained.

[0073] (Flame retardant) The resin composition may contain a flame retardant. The flame retardant is not particularly limited, and conventionally known ones can be used. Specifically, examples include organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, metal hydroxides, etc. The flame retardant may be used alone or in combination of two or more types.

[0074] If the resin composition contains a flame retardant, the amount is not particularly limited as long as it is sufficient to obtain the desired flame retardant effect. For example, it is preferably 1 to 300 parts by mass, and more preferably 2 to 150 parts by mass, per 100 parts by mass of the resin component.

[0075] (Colorants) The resin composition may further contain colorants. Examples of known colorants include carbon black, organic dyes, organic pigments, titanium dioxide, red lead, and red iron oxide. The amount of colorant can be appropriately selected depending on the purpose. One colorant may be used alone, or two or more colorants may be used in combination.

[0076] (Stress Relief Agent) The resin composition may contain stress relief agents such as silicone oil and silicone rubber particles. Including stress relief agents can further reduce package warping deformation and package cracking. Examples of stress relief agents include commonly used and known stress relief agents (flexible agents). Specifically, these include thermoplastic elastomers such as silicone-based, styrene-based, olefin-based, urethane-based, polyester-based, polyether-based, polyamide-based, and polybutadiene-based; rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder; and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. One type of stress relief agent may be used alone, or two or more types may be used in combination. Among these, silicone-based stress relief agents are preferred. Examples of silicone-based stress relief agents include those having epoxy groups, those having amino groups, and those modified with polyether.

[0077] [Method for preparing resin composition] The method for preparing the resin composition is not particularly limited. A common method is to thoroughly mix predetermined amounts of components using a mixer or the like, then melt-knead them using a mixing roll, extruder or the like, cool them, and pulverize them. More specifically, for example, a method can be used in which predetermined amounts of the above-mentioned components are uniformly stirred and mixed, then kneaded using a kneader, roll, extruder or the like that has been preheated to 70°C to 140°C, then cooled and pulverized.

[0078] The resin composition is preferably solid at room temperature and atmospheric pressure (for example, 25°C and atmospheric pressure). The shape of the solid resin composition is not particularly limited and can be in the form of powder, granules, tablets, etc. When the resin composition is in tablet form, the dimensions and mass should be such that they are suitable for the packaging molding conditions, from the viewpoint of ease of handling.

[0079] [Uses of the resin composition] The resin composition is used for encapsulating devices, and is preferably used for encapsulating power semiconductors. The method of encapsulating the devices is not particularly limited and may be a transfer molding method, injection molding method, compression molding method, etc.

[0080] <Semiconductor Device> The semiconductor device of this disclosure comprises an element and a cured product (sealed portion) of the sealing resin composition that seals the element. Examples of semiconductor devices include electronic component devices in which a semiconductor chip, an active element such as a transistor, a diode, or a thyristor, and a passive element such as a capacitor, a resistor, or a coil are mounted on a support member such as a lead frame, a wired tape carrier, a wiring board, glass, or a silicon wafer, and the necessary parts are sealed with the sealing resin composition of this disclosure. In particular, the sealing resin composition of this disclosure can be suitably used for sealing power semiconductors from the viewpoint of maintaining dielectric breakdown value. The most common method for sealing an element using the sealing resin composition of this disclosure is transfer molding, but injection molding, compression molding, etc., may also be used.

[0081] Figure 1 is a schematic cross-sectional view showing an example of the configuration of the semiconductor device 10 of this disclosure. The semiconductor device 10 includes a semiconductor chip (element) 20, a lead frame 30, and a sealing portion 40. The semiconductor chip 20 is mounted on the lead frame 30. The lead frame 30 is manufactured by precision pressing (punching, drawing, bending, etc.) a thin sheet of a Cu alloy material or Fe alloy material that has excellent electrical conductivity, mechanical strength, thermal conductivity, corrosion resistance, etc. The lead frame 30 has a die pad 31 on which the semiconductor chip 20 is mounted, and leads 33 connected to the die pad 31.

[0082] The die pad 31 has a plurality of electrically isolated segments 32, each corresponding to a plurality of connection terminals 55 of the semiconductor chip 20. Each of the plurality of connection terminals 55 is connected to the corresponding segment 32 among the plurality of segment segments 32. The connection terminals 55 are made of solder balls. The rewiring (not shown) of the semiconductor chip 20 and the die pad 31 of the lead frame 30 are electrically connected by the connection terminals 55. In this form of semiconductor device 10, bonding wires are not used for the electrical connection between the semiconductor chip 20 and the lead frame 30. Note that the connection terminals 55 may be made of something other than solder balls. For example, solder paste or conductive adhesive supplied onto the die pad 31 may be used to connect the rewiring to the die pad 31. Alternatively, the semiconductor chip 20 and the lead frame 30 may be electrically connected by bonding wires instead of the connection terminals 55.

[0083] The sealing portion 40 seals the die pad 31 and the semiconductor chip 20. That is, the die pad 31 and the semiconductor chip 20 are embedded inside the sealing portion 40. The sealing portion 40 is a cured product of the sealing resin composition of this disclosure. The leads 33 connected to each of the segmented pieces 32 of the die pad 31 extend to the outside of the sealing portion 40.

[0084] The embodiments of this disclosure will be described in detail below with reference to examples, but the embodiments of this disclosure are not limited to these examples.

[0085] <<Examples and Comparative Examples>> [Preparation of Resin Compositions> The following materials were mixed in the compositions shown in Table 1, and the resin compositions of the examples and comparative examples were prepared using a twin-screw kneader at a kneading temperature of 100°C. In Table 1, the units for the amount of each component are parts by mass, and "-" indicates that the component was not included.

[0086] (Epoxy resin) ・Epoxy resin: Triphenylmethane type epoxy resin (epoxy equivalent: 169 g / mol, softening point: 60°C) (Hardening agent) ・Hardening agent: Biphenyl aralkyl type phenolic resin (hydroxyl group equivalent: 136 g / eq) (Additives) ・Hardening accelerator 1: 2-phenyl-4-methylimidazole ・Hardening accelerator 2: 2-phenyl-4-methyl-5-hydroxymethylimidazole ・Hardening accelerator 3: 2-ethyl-4-methylimidazole ・Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane ・Release agent: Oxidized polyethylene wax ・Coloring agent: Carbon black (Hydroxyl group-containing compound) ・Hydroxyl group-containing compound 1: 2,3-dihydroxynaphthalene ・Hydroxyl group-containing compound 2: Gallic acid (Inorganic filler) ・Inorganic filler: Spherical silica with an average particle size of 25 μm

[0087] [Evaluation] The properties of the resin compositions prepared in the examples and comparative examples were evaluated by the following property tests. The results are shown in Table 1. Blank spaces indicate no data available.

[0088] (Adhesion) - Adhesion to copper (Cu) The resin composition was molded onto a copper plate under the above conditions to a size of 4 mm in diameter at the bottom, 3 mm in diameter at the top, and 4 mm in height, and then cured under the above conditions. After that, the shear adhesion strength (MPa) was determined at room temperature or while maintaining the temperature of the copper plate at 260°C, using a bond tester (Nordson Advanced Technologies, Inc., Series 4000) at a shear rate of 50 μm / s. - Adhesion to silver (Ag) The same test was performed using a silver-plated copper plate instead of a copper plate. - Adhesion to nickel (Ni) The same test was performed using a nickel-plated copper plate instead of a copper plate.

[0089] (Measurement of molding shrinkage rate) The resin composition was molded using a transfer molding machine under the following conditions: molding temperature of 175°C, molding pressure of 6.9 MPa, and curing time of 120 seconds, to obtain a plate-shaped molded product (length 127 mm, width 12.7 mm, thickness 6.4 mm). The molding shrinkage rate A (%) (molding shrinkage rate AM in Table 1) was calculated from the length D of the mold cavity at 25°C, which was measured in advance, and the length d of the molded product at room temperature (25°C) using the following formula. The results are shown in Table 1. Molding shrinkage rate A (%) = ((D - d) / D) × 100

[0090] A resin composition was molded using a transfer molding machine under the following conditions: molding temperature 175°C, molding pressure 6.9 MPa, and curing time 120 seconds, to obtain a plate-shaped molded product (length 127 mm, width 12.7 mm, thickness 6.4 mm). This molded product was cured at 175°C for 5 hours to obtain a plate-shaped cured product. The molding shrinkage rate B (%) (molding shrinkage rate AC in Table 1) was calculated using the following formula from the previously measured mold cavity length D at 25°C and the cured product length d at room temperature (25°C). The results are shown in Table 1. Molding shrinkage rate B (%) = ((D - d) / D) × 100

[0091]

[0092] As shown in Table 1, the molding shrinkage rate was reduced in Examples 1 to 8 compared to Comparative Examples 1 to 3.

[0093] The disclosure of Japanese Patent Application No. 2025-056933, filed on 28 March 2025, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A encapsulating resin composition comprising an epoxy resin and a curing accelerator, wherein the content of the curing accelerator is 1% by mass to 10% by mass relative to the epoxy resin.

2. The sealing resin composition according to claim 1, further comprising an aromatic ring and two or more hydroxyl groups bonded to adjacent positions of the aromatic ring, or a hydroxyl group-containing compound comprising a hydroxyl group and one or more methoxy groups.

3. The encapsulating resin composition according to claim 2, wherein the hydroxyl group-containing compound comprises a benzene ring or a naphthalene ring.

4. The encapsulating resin composition according to claim 2, wherein the content of the hydroxyl group-containing compound is 0.5% by mass to 10% by mass relative to the epoxy resin.

5. The encapsulating resin composition according to claim 1, wherein the curing accelerator comprises an imidazole compound.

6. The encapsulating resin composition according to claim 1, further comprising a phenol curing agent.

7. The encapsulation resin composition according to any one of claims 1 to 6, for use in encapsulating power semiconductors.

8. A semiconductor device comprising: a semiconductor chip; a lead frame on which the semiconductor chip is mounted; and a cured product of the sealing resin composition according to any one of claims 1 to 6 for sealing the semiconductor chip.

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