JPWO2019171993A1 - Epoxy resin composition and its cured product - Google Patents

Abstract

An epoxy resin cured product having excellent tracking resistance, a balance with heat resistance, and excellent thermal decomposition stability can be obtained, and an epoxy resin composition, an epoxy resin cured product, and a semiconductor particularly suitable for encapsulating a power semiconductor can be obtained. provide. (A) Epoxy resin represented by the following general formula (1), (B) Non-aromatic epoxy resin or non-silicone rubber having a 5% weight loss temperature of 260 ° C. or higher, (C) Curing agent, and (D) An epoxy resin composition containing a curing accelerator as an essential component, which is characterized by containing 1 to 50% by weight of the component (B) with respect to the total of the components (A) to (D). Resin composition. [Chemical formula 1] However, n represents a number from 0 to 20, and G represents a glycidyl group.

Description

The present invention relates to an epoxy resin composition, an epoxy resin cured product, and a semiconductor device. Specifically, an epoxy resin cured product having excellent heat resistance and thermal decomposition stability can be obtained, and the tracking resistance is excellent, particularly power. The present invention relates to an epoxy resin composition suitable for encapsulating a semiconductor, an epoxy resin cured product, and a semiconductor device.

Epoxy resins are industrially used in a wide range of applications. As an example, it is used as a sealing material in semiconductor devices, but the required performance in semiconductor devices has become more sophisticated in recent years, and the required power density has become an area that is difficult to reach with conventional Si devices. .. Under these circumstances, SiC power devices are one of the devices that are expected to have higher power densities and are being developed in recent years. In order to achieve higher power densities, the temperature of the chip surface during operation Reaches more than 200 ° C. Therefore, it is desired to develop a sealing material that can withstand the temperature and maintain its physical properties for 1000 hours or more.

In particular, in automotive semiconductor devices, various sensors and electronic control units that support safety control are being integrated, and the engine and power module are exposed to heat generation or heat generation due to integration for a long time. There is an increasing demand for materials that can withstand high temperature environments.

Furthermore, not only thermal durability but also demand for insulation performance due to high voltage and high current is increasing. The circuit pitch width and the distance between lead terminals have become smaller not only in power-based semiconductor devices used at high voltage such as in-vehicle, train, wind power generation, and solar power generation, but also in semiconductor packages that are becoming smaller and thinner. In order to secure the clearance and creepage distance for electrically insulating them, the sealing material and the substrate material are required to have tracking resistance of 600 V or more.

Methods for improving tracking resistance include 1) suppression of thermal / oxidative decomposition (increased thermal decomposition start temperature, suppression of volatile gas content), 2) improvement of electrical insulation at high temperatures (improvement of glass transition temperature). , 3) It is said that suppression of carbonization (reduction of residual coal ratio, blending of inorganic filler), etc. is effective, and various methods have been proposed. For example, a semiconductor device (Patent Document 1) in which a silicone resin is used as a sealing material having high tracking resistance and excellent processability on the surface, and the content of halogen and antimony compound is 0.1% by weight or less. A flame-retardant non-halogen epoxy resin composition having excellent tracking resistance in which at least one of the curing agents is a polycondensate of phenols, a compound having a triazine ring, or aldehydes (Patent Document 2), epoxidized cyclic conjugation. A sealing material for semiconductor chips (Patent Document 3) has been proposed, which may contain a diene polymer as a resin component and may contain an inorganic filler conductive filler. Further, as a semiconductor encapsulation resin composition having excellent tracking resistance, a semiconductor encapsulation resin composition containing an alicyclic epoxy resin system having a cyclohexane polyether skeleton and a dicyclopentadiene type phenol resin, etc., which does not contain a benzene skeleton. A product (Patent Document 4) and an epoxy resin composition for semiconductor encapsulation (Patent Document 5) in which a metal hydroxide is blended with an epoxy resin as an inorganic filler have been proposed, but the heat resistance is lowered. On the other hand, an epoxy resin composition for semiconductor encapsulation (Patent Document 6) containing an epoxy resin, a curing agent, an inorganic filler and a spherical silicone powder is disclosed, and this resin composition attempts to improve tracking resistance. It's not a thing. Further, the sealing resin composition containing silicone rubber powder (Patent Document 7) is excellent in tracking property, but is not sufficient in heat resistance. In addition, there is a concern that silicone-based rubber powder may cause contact failure when low-molecular components volatilize. Epoxy resins, epoxy resin compositions, and cured products having a biphenol-biphenyl aralkyl structure have already been disclosed as structures having excellent heat resistance, but tracking resistance has not been described (Patent Document 8, Patent Documents). 9).

Japanese Unexamined Patent Publication No. 3-151674 JP-A-11-209569 Japanese Unexamined Patent Publication No. 2003-20325 Japanese Unexamined Patent Publication No. 2005-213299 Japanese Unexamined Patent Publication No. 2008-143950 Japanese Unexamined Patent Publication No. 2009-275146 JP 2013-203865 WO2011 / 074517A Japanese Unexamined Patent Publication No. 2013-209503

In the conventional technique, since the tracking resistance, the heat resistance and the flame retardancy are in a trade-off relationship, it is difficult to achieve both the heat resistance of 200 ° C. or higher and the tracking resistance of 600 V. Therefore, according to the present invention, an epoxy resin cured product having particularly excellent tracking resistance, a balance with heat resistance, and excellent thermal decomposition stability can be obtained, and an epoxy resin composition, epoxy, which is particularly suitable for encapsulating a power semiconductor. It is intended to provide a cured resin product and a semiconductor.

但し、ｎは０〜２０の数を示し、Ｇはグリシジル基を示す。In the present invention, the following components (A) to (D);
(A) Aromatic epoxy resin represented by the following general formula (1),
(B) Modified selected from non-aromatic epoxy resin or non-silicone rubber having a 5% weight loss temperature of 260 ° C. or higher determined from TG / DTA measurement at a temperature rise rate of 10 ° C./min under a nitrogen stream. Pledge,
An epoxy resin composition containing (C) a curing agent and (D) a curing accelerator as essential components, and contains 1 to 50% by weight of the component (B) with respect to the total of the components (A) to (D). It is an epoxy resin composition characterized by the above.

However, n represents a number from 0 to 20, and G represents a glycidyl group.

As the component (B), at least one epoxy resin selected from glycidyl esters of dihydric aliphatic carboxylic acids having 15 to 64 carbon atoms or glycidyl ethers of dihydric aliphatic alcohols having 15 to 64 carbon atoms is used. Examples thereof include a modifier made of a bifunctional epoxy resin containing the mixture, or a rubber-based modifier made of a styrene rubber or an acrylic rubber.

但し、Ｒは水素原子又は炭素数１〜６の炭化水素基を示し、ｍは０又は１の数を示す。Examples of the component (C) include a curing agent containing a phenol resin represented by the following general formula (2).

However, R represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and m represents a number of 0 or 1.

Further, the present invention is an epoxy resin cured product obtained by curing the above epoxy resin composition. Further, the present invention is a semiconductor device in which a semiconductor element is sealed with the above-mentioned epoxy resin composition.

According to the present invention, it is possible to provide an epoxy resin composition, an epoxy resin cured product, and a semiconductor device that have both tracking resistance and heat resistance, which are difficult with conventional techniques. Further, the epoxy resin composition is excellent in fluidity and moldability, and the cured product is excellent in glass transition temperature of 200 ° C. or higher, long-term thermal stability, and flame retardancy. Furthermore, since it is a non-silicone type, it is suitable for in-vehicle use.

Hereinafter, the present invention will be described in detail.

The epoxy resin composition of the present invention contains the following components (A) to (D) as essential components. (A) Aromatic epoxy resin represented by the above general formula (1), (B) Modifier selected from non-aromatic epoxy resin or non-silicone rubber, (C) Curing agent, and (D). ) Curing accelerator.

The component (A) is an epoxy resin represented by the general formula (1), and is also called a biphenyl aralkyl type epoxy resin because it has a biphenyl structure. In the formula, n represents a number from 0 to 20 and G represents a glycidyl group. n is the number of repetitions and indicates a number of 0 or more, and the average value (number average) thereof is 1.3 to 20, preferably 1.5 to 15, more preferably 1.7 to 10, and 2 to 6 Is even more preferable. The content of the n = 0 component in which n is 0 is preferably 30 area% or less as measured by gel permeation chromatography (GPC) from the viewpoint of reactivity and fluidity. If it is more than that, the crystallinity becomes strong and it becomes difficult to handle. Further, when it is used by being dissolved in an organic solvent for use in a laminated board or the like, it is preferably less than 15 area%, preferably 10 area% or less, from the viewpoint of solvent solubility. The content of n = 5 components or more is 15 area% or more, preferably 20 area% or more, from the viewpoint of improving heat resistance. The weight average molecular weight (Mw) measured by GPC is preferably 1,000 to 8,000, more preferably 2,000 to 7,000, and even more preferably 2,000 to 5,000.

但し、ｎは０〜２０の数を示す。

但し、Ｘは水酸基、ハロゲン原子又は炭素数１〜６のアルコキシ基を示す。The epoxy resin can be produced by reacting a multivalent hydroxy resin represented by the following general formula (3) with epichlorohydrin. Since this polyvalent hydroxy resin has a biphenyl structure, it is also called a biphenyl aralkyl type droxy resin. Then, this biphenyl aralkyl type hydroxy resin is obtained by reacting biphenols with a biphenyl-based condensing agent represented by the following general formula (4).

However, n represents a number from 0 to 20.

However, X represents a hydroxyl group, a halogen atom, or an alkoxy group having 1 to 6 carbon atoms.

Examples of biphenols as a synthetic raw material for the biphenyl aralkyl type hydroxy resin include 4,4'-dihydroxybiphenyls.

Specific examples of the biphenyl-based condensing agent include 4,4'-bishydroxymethylbiphenyl, 4,4'-bischloromethylbiphenyl, 4,4'-bisbromomethylbiphenyl, and 4,4'-bismethoxymethylbiphenyl. , 4,4'-bisethoxymethylbiphenyl. From the viewpoint of reactivity, 4,4'-bishydroxymethylbiphenyl and 4,4'-bischloromethylbiphenyl are preferable, and from the viewpoint of reducing ionic impurities, 4,4'-bishydroxymethylbiphenyl, 4 , 4'-bismethoxymethylbiphenyl is preferred.

The molar ratio at the time of reaction is preferably 1 mol or less of the biphenyl-based condensing agent with respect to 1 mol of 4,4'-dihydroxybiphenyl, generally in the range of 0.1 to 0.7 mol, and more. It is preferably in the range of 0.2 to 0.5 mol. If it is less than this, the crystallinity becomes strong, the solubility in epichlorohydrin at the time of synthesizing the epoxy resin decreases, the melting point of the obtained epoxy resin becomes high, and the handleability deteriorates. On the other hand, if the amount is more than this, the crystallinity of the resin is lowered and the softening point and the melt viscosity are increased, which hinders handling workability and moldability.

When chloromethylbiphenyl is used as the condensing agent, the reaction can be carried out without a catalyst, but usually, this condensation reaction is carried out in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from well-known inorganic acids and organic acids. For example, mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid, formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid and metasulfone can be appropriately selected. Examples thereof include organic acids such as acids and trifluoromethsulfonic acids, Lewis acids such as zinc chloride, aluminum chloride, iron chloride and boron trifluoride, and solid acids.

This reaction is carried out at 10 to 250 ° C. for 1 to 30 hours. Further, during the reaction, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, diethylene glycol dimethyl ether and triglime, and aromatic compounds such as benzene, toluene, chlorobenzene and dichlorobenzene are used as solvents. Can be used. After completion of the reaction, if necessary, the solvent or water and alcohols produced by the condensation reaction are removed.

A method for producing a biphenyl aralkyl type epoxy resin represented by the general formula (1) by reacting the above biphenyl aralkyl type hydroxy resin with epichlorohydrin will be described. This reaction can be carried out in the same manner as the well-known epoxidation reaction.

For example, after dissolving a biphenyl aralkyl type hydroxy resin in excess epichlorohydrin, 1 to 150 ° C., preferably 60 to 120 ° C. in the presence of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. A method of reacting for 10 hours can be mentioned. The amount of epichlorohydrin used at this time is in the range of 0.8 to 2.0 mol, preferably 0.9 to 1.2 mol, with respect to 1 mol of the hydroxyl group in the polyvalent hydroxy resin. After completion of the reaction, excess epichlorohydrin was distilled off, the residue was dissolved in a solvent such as toluene and methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent was distilled off. The target epoxy resin represented by 1) can be obtained. When carrying out the epoxidation reaction, a catalyst such as a quaternary ammonium salt may be used.

The purity of the biphenyl aralkyl type epoxy resin, particularly the amount of hydrolyzable chlorine, should be smaller from the viewpoint of improving the reliability of the electronic components to be applied. Although not particularly limited, it is preferably 1000 ppm or less, and more preferably 500 ppm or less. The hydrolyzable chlorine in the present invention means a value measured by the following method. That is, after dissolving 0.5 g of the sample in 30 ml of dioxane, adding 1N-KOH and 10 ml, boiling and refluxing for 30 minutes, cooling to room temperature, further adding 100 ml of 80% acetone water, and potentiometric titration with 0.002N-AgNO ₃ aqueous solution. It is a value that can be obtained by titration.

In addition to the epoxy resin of the component (A), an epoxy resin as another component may be blended in the epoxy resin composition of the present invention. The epoxy resin as another component is also referred to as a component (F).
The component (F) is preferably an aromatic epoxy resin obtained by epoxidizing a phenolic hydroxyl group.
As such an epoxy resin, any ordinary aromatic epoxy resin having two or more epoxy groups in the molecule can be used. For example, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 3,3', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl, resorcin, naphthalenediols. Epoxidates of divalent phenols such as, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolac, etc. Phenol epoxidants, cocondensate resin epoxides obtained from dicyclopentadiene and phenols, cocondensate resin epoxidates obtained from cresols, formaldehyde and alkoxy group substituted naphthalenes, phenols and paraxylylene chloride chlorides. Phenolic aralkyl resins obtained from the above, epoxidates of biphenyl aralkyl type phenolic resins obtained from phenols and bischloromethylbiphenyl, etc., epoxidates of naphthol aralkyl resins synthesized from naphthols and paraxylylene chloride chloride, etc. And so on. These epoxy resins can be used alone or in admixture of two or more. In the epoxy resin composition of the present invention, the blending amount of the epoxy resin represented by the general formula (1) is preferably in the range of 5 to 100 wt%, preferably 60 to 100 wt% in the entire epoxy resin. ..

The component (B) is a non-silicone-based modifier selected from a non-aromatic epoxy resin or a non-silicone rubber, and this modifier is used at a temperature rise rate of 10 ° C./min under a nitrogen stream. The 5% weight loss temperature determined from the TG / DTA measurement is 260 ° C. or higher. Then, this modifier acts as a modifier for improving tracking resistance.

When the above modifier is added, it is considered that the modifier undergoes phase separation in the resin, thereby suppressing the aggregation of the carbonized layer generated during thermal decomposition, and improvement in tracking resistance can be expected.

By using a modifier having a 5% weight loss temperature of 260 ° C. or higher, deterioration of mechanical strength can be prevented even when used at a high temperature of 200 ° C. or higher.

By using a non-silicone type modifier as the modifier, there are the following advantages. Silicone-based modifiers such as silicone rubber may cause contact failure when low-molecular-weight components volatilize, and it is difficult to obtain a uniform composition that is easily phase-separated from epoxy resin. However, such a problem is solved. In addition, the non-silicone type is more advantageous in terms of cost.

The content of the modifier is 1 to 50% by weight, preferably 2 to 30% by weight, based on the total of the above components (A) to (D).
From another viewpoint, the range of 1 to 50 parts by weight is preferable with respect to 100 parts by weight of the total amount of the resin component in the epoxy resin composition, but it is preferably 2 to 30 parts by weight. If it is smaller than this, the effect of suppressing aggregation of the carbonized layer is low, and if it is larger than this, the glass transition temperature Tg of the cured product is lowered and the mechanical strength is also lowered.

The modifier is preferably dispersed in a phase-separated state of 10 μm or less or in the form of particles. The particle size (median average diameter) is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 5 μm, and particularly preferably 0.1 μm to 1 μm.

These modifiers may be well known in the art and are not particularly limited. The modifier having excellent thermal stability is at least one selected from glycidyl esters of dihydric aliphatic carboxylic acids having 15 to 64 carbon atoms and glycidyl ethers of dihydric aliphatic alcohols having 15 to 64 carbon atoms. A bifunctional epoxy resin containing an epoxy resin as an essential component is preferable.
Further, rubbers made of styrene rubber or acrylic rubber are also excellent as modifiers.

Examples of the divalent aliphatic carboxylic acid having 15 to 64 carbon atoms include 2-dodecyl dicarboxylic acid, hexadecanedioic acid, 8-hexadecenedioic acid, 8,9-diethylhexadecanedioic acid, eikosandioic acid, and 7-vinyl. An aliphatic dicarboxylic acid such as tetradecanedioic acid, 1,16- (6-ethylhexadecane) dicarboxylic acid, 1,18- (7,12-octadecadien) dicarboxylic acid, 1,12- (diethyldodecane) dicarboxylic acid, etc. , Dimeric acid whose main component is a dibasic acid having 36 carbon atoms obtained by an intermolecular reaction of two or more unsaturated fatty acids (linoleic acid, oleic acid, etc.) and water obtained by hydrogenating the dimeric acid. Examples thereof include dicarboxylic acid, but the present invention is not particularly limited. By diglycidyl esterifying these divalent aliphatic carboxylic acids using a known epoxidation technique, epoxy resins of glycidyl esters of divalent aliphatic carboxylic acids having 15 to 64 carbon atoms can be obtained.

Examples of the divalent aliphatic alcohol having 15 to 64 carbon atoms include long-chain aliphatic alcohols such as 1,15-pentadecanediol, 1,16-hexadecanediol, 1,18-octadecandiol, and 1,19-nonadecandiol. Polyethylene glycol such as diol, octaethylene glycol, nonaethylene glycol, polypropylene glycol such as pentapropylene glycol and hexapropylene glycol, and cyclocycle such as 4,4'-(propane-2,2-diyl) bis (cyclohexanol). Examples thereof include a contained diol, a dimer diol obtained by reducing the carboxyl group of the above-mentioned dimer acid or hydrogenated dimer acid to a hydroxyl group, a hydrogenated dimer diol, and the like, but the present invention is not particularly limited. By diglycidyl etherizing these dihydric aliphatic alcohols using a known epoxidation technique, epoxy resins of glycidyl ethers of dihydric aliphatic alcohols having 15 to 64 carbon atoms can be obtained.

Styrene-based rubber and acrylic-based rubber include styrenes (including substituted styrene), acrylics (acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, etc.) as rubber components (monomers) or as part of raw materials. Acrylonitrile, etc.) can be used. Further, non-silicone natural rubber, diene rubber such as butadiene rubber can also be used.

Examples of the styrene-based rubber include acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile chlorinated polyethylene styrene copolymer (ACS), acrylonitrile ethylene propylene rubber styrene copolymer (AES), and acrylonitrile styrene acrylate copolymer (ASA). ), Methyl methacrylate acrylonitrile butadiene styrene copolymer (MABS), methyl methacrylate butadiene styrene copolymer (MBS), styrene butadiene copolymer (SB), acrylonitrile styrene copolymer (SAN), styrene butadiene styrene block copolymer (SBS), styreneethylenebutylene styrene block copolymer (SEBS), styreneethylenepropylene styrene block copolymer (SEPS), styreneisoprene styrene block copolymer (SIS), acryliconitrile styrenedimethylsiloxane alkyl copolymer, etc. Can be mentioned. Among them, from the viewpoint of reducing elasticity and improving impact resistance, it is incompatible with styrene such as styrene-butadiene copolymer (SB), methyl methacrylate-butadiene-styrene copolymer (MBS), and acrylonitrile styrene-dimethylsiloxane alkyl copolymer. Rubber obtained by copolymerization with a monomer having a saturated double bond is preferable.

As the acrylic rubber, for example, those obtained by copolymerizing one or more kinds of alkyl (meth) acrylates and one or more kinds of vinyl monomers copolymerizable therewith are preferably mentioned, and alkyl (meth) acrylates are preferable. As the vinyl monomer copolymerizable with, for example, a crosslinkable monomer is preferable, and an aromatic polyfunctional vinyl monomer such as divinylbenzene and divinyltoluene; ethylene glycol di (meth) acrylate and propylene glycol di Di or tri (meth) acrylic acid esters of polyhydric alcohols such as (meth) acrylates, 1,3-butanediol di (meth) acrylates, 1,4-butanediol di (meth) acrylates; allyl (meth) acrylates, Examples of di or triallyl compounds such as diallyl phthalate, diallyl sebacate, triallyl triazine, triallyl cyanurate, and triallyl isocyanurate can be mentioned, and one of these may be used alone or in combination of two or more. You may use it.

The component (C) is a curing agent for epoxy resins. As the curing agent, a known curing agent for epoxy resin can be used, but in the field where high electrical insulation is required such as a semiconductor encapsulant, it is preferable to use polyhydric phenols as the curing agent. .. Specific examples of the curing agent are shown below.

Examples of polyhydric phenols include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, hydroquinone, resorcin, catechol, biphenols, naphthalenediols, and tris- (4-hydroxyphenyl). ) Methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolac, naphthol novolac, dicyclopentadiene-type phenol resin, phenol aralkyl resin, etc. 2 of phenols, phenols, naphthols, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcin, catechol, naphthalenediol, etc. Valuable phenols and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, p-xylylene glycol dimethyl ether, divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyls, divinylbiphenyl, diisopropenylbiphenyls Polyhydric phenolic compounds synthesized by reaction with cross-linking agents such as, biphenyl aralkyl type phenol resins obtained from phenols and bischloromethylbiphenyl, etc., naphthol aralkyl resins synthesized from naphthols and paraxylylene chloride chloride, etc. And so on.

Among these, a preferable phenolic curing agent is an aralkyl type phenol resin represented by the above general formula (2).
In the general formula (2), R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, but is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. m represents a number of 0s or 1s.

By using the above-mentioned aralkyl type phenol resin or a curing agent containing it, a high Tg property of 200 ° C. or higher required for a power device encapsulant was found, and long-term thermal stability was achieved by maintaining a glass state during a long-term heat resistance test. Sex is expressed.

The aralkyl-type phenol resin represented by the general formula (2) can be produced by reacting salicylaldehyde or p-hydroxyaldehyde with a phenolic hydroxyl group-containing compound.

The amount of the curing agent to be blended is considered in consideration of the equivalent balance between the epoxy group in the epoxy resin and the active hydrogen (hydroxyl group in the case of polyhydric phenols) in the curing agent. The equivalent ratio of the epoxy resin to the curing agent is usually in the range of 0.2 to 5.0, preferably in the range of 0.5 to 2.0, and more preferably in the range of 0.8 to 1.5. Is. Whether it is larger or smaller than this, the curability of the epoxy resin composition is lowered, and the heat resistance, mechanical strength, etc. of the cured product are lowered.

Further, in this epoxy resin composition, another kind of curing agent may be blended as a curing agent component in addition to the aromatic hydroxy compound. Examples of the curing agent in this case include dicyandiamide, acid anhydrides, aromatics and aliphatic amines. In the epoxy resin composition of the present invention, one or a mixture of two or more of these curing agents can be used.

Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl anhydride hymic acid, dodecinyl succinic anhydride, and nadic acid anhydride. There are phthalic anhydride and the like.

Examples of amines include aromatic amines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, m-phenylenediamine, and p-xylylenediamine, ethylenediamine, and the like. There are aliphatic amines such as hexamethylenediamine, diethylenetriamine and triethylenetetramine.

The component (D) is a curing accelerator for the epoxy resin composition. The curing accelerator may be well known in the technical field of epoxy resin, and is not particularly limited. Examples include amines, imidazoles, organic phosphines, Lewis acids and the like.
Specifically, tertiary amines such as 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol, 2 -Imidazoles such as methyl imidazole, 2-phenyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl-4-methyl imidazole, 2-heptadecyl imidazole, tributylphosphine, methyldiphenylphosphine, triphenylphosphine, Organic phosphines such as diphenylphosphine and phenylphosphine, tetra-substituted phosphonium-tetra-substituted borates such as tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenylborate, tetrabutylphosphonium / tetrabutylborate, 2-ethyl-4. -There are tetraphenylborone salts such as methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate. The amount to be added is usually in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin.

In the epoxy resin composition of the present invention, oligomers or polymer compounds such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, inden resin, inden-kumaron resin, and phenoxy resin are used as other modifiers. It may be blended as appropriate. The amount added is usually in the range of 2 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin.

In addition, the epoxy resin composition of the present invention may contain additives such as an inorganic filler, a pigment, a flame retardant, a rock denaturing agent, a coupling agent, and a fluidity improver. Examples of the inorganic filler include spherical or crushed fused silica, silica powder such as crystalline silica, alumina powder, glass powder, mica, talc, calcium carbonate, alumina, hydrated alumina, and the like, and are used for semiconductor sealing. When used as a stopper, the blending amount is preferably 70% by weight or more, more preferably 80% by weight or more.

Examples of the pigment include organic or inorganic extender pigments and reptile pigments. Examples of the rocking denaturing agent include castor oil, aliphatic amide wax, polyethylene oxide wax, and organic bentonite.

Further, if necessary, the resin composition of the present invention includes a release agent such as carnauba wax and OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and trioxide. Flame retardants such as antimony and lubricants such as calcium stearate can be used.

The epoxy resin composition of the present invention is in a varnish state in which a part or all of it is dissolved in an organic solvent, and then impregnated with a fibrous material such as a glass cloth, an aramid non-woven fabric, or a polyester non-woven fabric such as a liquid crystal polymer, and then a solvent. It can be removed to make a prepreg. When a solvent-insoluble component such as an inorganic filler is contained, it is not necessary to dissolve it, but it is desirable to suspend the solution to obtain a classically uniform solution. Further, depending on the case, a laminate can be obtained by applying it on a sheet-like material such as a copper foil, a stainless steel foil, a polyimide film, or a polyester film.

If the epoxy resin composition of the present invention is heat-cured, it can be made into an epoxy resin cured product, and this cured product is excellent in terms of low hygroscopicity, high heat resistance, adhesion, flame retardancy and the like. Become. The cured product can be obtained by molding the epoxy resin composition by a method such as casting, compression molding, or transfer molding. The temperature at this time is usually in the range of 120 to 220 ° C. The epoxy resin composition of the present invention is particularly excellent for a sealing material. Further, the semiconductor device of the present invention can be obtained by encapsulating a semiconductor element with this epoxy resin composition.

The present invention will be specifically described with reference to Synthesis Examples, Examples and Comparative Examples. However, the present invention is not limited thereto. Unless otherwise specified, "parts" represents parts by weight and "%" represents% by weight. In addition, the measurement methods were as follows.

1) Measurement of epoxy equivalent Using a potentiometric titrator, chloroform was used as a solvent, a brominated tetraethylammonium acetic acid solution was added, and the potentiometric titrator was used for measurement using a 0.1 mol / L perchloric acid-acid solution.

2) Melting point The DSC peak temperature was determined by a differential scanning calorimetry device (EXSTAR6000 DSC / 6200 manufactured by SII Nanotechnology Co., Ltd.) under the condition of a heating rate of 5 ° C./min. That is, this DSC peak temperature was used as the melting point of the epoxy resin.

3) Melt viscosity Measured at 150 ° C. using a CAP2000H type rotational viscometer manufactured by BROOKFIELD.

4) Dissolve 1.0 g of a total chlorine sample in 25 ml of butyl carbitol, add 25 ml of a 1N-KOH propylene glycol solution, heat and reflux for 10 minutes, cool to room temperature, add 100 ml of 80% acetone water, and add 0.002N. It was determined by performing potentiometric titration with -AgNO ₃ aq.

5) GPC measurement A main body (manufactured by Tosoh Corporation, HLC-8220GPC) equipped with columns (manufactured by Tosoh Corporation, TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL) in series was used, and the column temperature was set to 40 ° C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 mL / min, and a differential refractive index detector was used as the detector. As the measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF, and 50 μL of the sample filtered through a microfilter was used. For data processing, GPC-8020 Model II version 6.00 manufactured by Tosoh Corporation was used.

6) Glass transition point (Tg)
Tg was determined under the condition of a heating rate of 10 ° C./min using a thermomechanical measuring device (EXSTAR6000TMA / 6100 manufactured by SII Nanotechnology).

7) 5% weight loss temperature (Td5), residual coal rate thermogravimetric / differential thermal analyzer (EXSTAR6000TG / DTA6200 manufactured by SII Nanotechnology) under nitrogen atmosphere, heating rate 10 ° C / min. The 5% weight loss temperature (Td5) was measured.
Further, under the above conditions, the weight loss at 700 ° C. was measured and converted into the resin component excluding the inorganic filler to calculate the residual carbon ratio of the resin component at 700 ° C.

8) PTI value (600V)
A cured resin product (20 x 20 x 3 mm) was used as a test piece in accordance with IEC60112. The electrodes were platinum and had a tip angle of 30 degrees, and the electrode arrangement was 4.0 mm and the facing angle was 60 degrees. A 0.1% ammonium chloride solution was used as the electrolytic solution. After adjusting the condition of the test piece at 23 ° C. and 50% RH for 8 hours, a voltage of 600 V was applied in an environment of 23 ° C. and 50% RH, an electrolytic solution was dropped, and the test surface caused tracking failure. The number of drops up to was calculated. Moreover, the test was carried out 5 times, and the number which did not cause the tracking destruction even if it exceeded 50 drops at 600V was measured. As the measuring device, HAT-112-3 manufactured by Yamayo Tester Co., Ltd. was used.

Synthesis example 1
75.0 g of 4,4'-dihydroxybiphenyl, 115.5 g of diethylene glycol dimethyl ether, and 40.5 g of 4,4'-bischloromethylbiphenyl are charged in a 1000 ml 4-neck flask, and the temperature is raised to 170 ° C. with stirring under a nitrogen stream. It was warmed and reacted for 20 hours. After the reaction, 46.4 g of diethylene glycol dimethyl ether was recovered. To this reaction mixture, 446.5 g of epichlorohydrin was added, and 69.4 g of a 48% aqueous sodium hydroxide solution was added dropwise at 62 ° C. over 4 hours under reduced pressure (about 130 Torr). During this period, the produced water was removed from the system by azeotropic boiling with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropping, the reaction was continued for another 1 hour. Then, epichlorohydrin was distilled off, methyl isobutyl ketone was added, the salt was removed by washing with water, filtration and washing were performed, and then methyl isobutyl ketone was distilled off under reduced pressure to obtain 141 g of epoxy resin (epoxy resin 1). .. The epoxy equivalent of this epoxy resin was 198. The peak temperature of this epoxy resin in the DSC measurement result was 126 ° C., and the melt viscosity at 150 ° C. was 0.25 Pa · s.

Synthesis example 2
500 g of phenol (8.0 times mol with respect to dicyclopentadiene) and 9.5 g of boron trifluoride ether complex as an acid catalyst were placed in a 1 L 4-neck flask and the temperature was raised to 120 ° C. Next, 88 g of dicyclopentadiene was added dropwise over 6 hours while stirring at 120 ° C., and the mixture was further aged at 130 ° C. for 4 hours, then neutralized to recover phenol. Subsequently, it was dissolved in 300 g of MIBK, washed with water four times at 80 ° C., and the MIBK was distilled off under reduced pressure to obtain 179 g of a polyvalent hydroxy compound. Its hydroxyl group equivalent is 178 g / eq. The softening point was 93 ° C., and the weight average molecular weight was 422.

Synthesis example 3
150 g of the resin obtained in Synthesis Example 2, 398 g of epichlorohydrin, and 59 g of diethylene glycol dimethyl ether were placed in a four-neck separable flask and dissolved by stirring. After uniformly dissolving, the temperature was maintained at 65 ° C. under reduced pressure of 130 mmHg, 68.2 g of a 48% sodium hydroxide aqueous solution was added dropwise over 4 hours, and the water and epichlorohydrin reflux-distilled during the addition were separated in a separation tank to remove epichlorohydrin. Returned to the reaction vessel, water was removed from the system and reacted. After completion of the reaction, the salt produced by filtration was removed, the mixture was further washed with water, and epichlorohydrin was distilled off to obtain 157 g of an epoxy resin (epoxy resin 2). The epoxy equivalent of the obtained resin was 243 g / eq. The softening point was 84 ° C.

Synthesis example 4
Dimerdiol (CRODA's Pripol 20) in a 2000 ml 4-neck flask
33, hydroxyl group equivalent 270 g / eq. ) 300.0 g, epichlorohydrin 308.3 g, toluene 120.0 g, and water 6.2 g were charged and dissolved by raising the temperature to 50 ° C. with stirring under a nitrogen stream. After dissolution, 6.0 g of benzyltrimethylammonium chloride was added, and 13.6 g of 95.5% solid potassium hydroxide was divided and added over 2 hours. After the reaction for another 2.5 hours, 300 g of toluene and 387.5 g of water were added, the salt produced by the liquid separation was removed, epichlorohydrin, toluene and water were distilled off, and 543.2 g of toluene was added and dissolved at 80 ° C. .. Then, 12.3 g of a 48.8% potassium hydroxide aqueous solution was added to carry out a purification reaction, and after neutralization, washing with water and filtration, toluene was distilled off to obtain 325.9 g of a modifier a which is a liquid epoxy resin. .. The epoxy equivalent of the modifier a is 360 g / eq. The viscosity at 25 ° C. was 243 Pa · s. The temperature of Td5 was 324 ° C.

The explanation of the abbreviations used in the examples is as follows.
(Epoxy resin)
Epoxy resin 1; Epoxy resin obtained in Synthesis Example 1 Epoxy resin 2; o-cresol novolac type epoxy resin (epoxy equivalent 200, softening point 65 ° C., manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Epoxy resin 3; Epoxy resin (modifier) obtained in Synthesis Example 3
Modifier a; Modifier modified agent b obtained in Synthesis Example 4; Radical-controlled polymerized acrylic block copolymer having an ABA structure containing polybutyl acrylate as a soft component and polymethylene methacrylate as a hard component (NANOSTRENGTH M51, Alchema Co., Ltd., Td5; 291 ° C)
Modifier c; Indene oligomer (IP-100; manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., softening point 101 ° C., 150 ° C., melt viscosity 1.3 Pa · s, Td5; 243 ° C.)
(Hardener)
Hardener 1; Triphenol methane type polyhydric hydroxy resin (TPM-100, manufactured by Gun Ei Chemical Industry Co., Ltd., OH equivalent 97.5, softening point 105 ° C.)
Hardener 2; Phenolic novolac type polyvalent hydroxy resin (BRG-557, manufactured by Gun Ei Chemical Industry Co., Ltd., OH equivalent 105, softening point 80 ° C.)
(Curing accelerator)
2-Phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW, manufactured by Shikoku Chemicals Corporation)
(Other)
Silica filler; Spherical silica (FB-8S, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Carnauba wax; (TOWAX171, manufactured by Toa Kasei Co., Ltd.)
Carbon black; (MA-100, manufactured by Mitsubishi Chemical Corporation)

Example 1
As the epoxy resin component, the epoxy resin 1; 64.0 g, the modifier a; 5.1 g, and the curing agent 13 32.9 g obtained in Synthesis Example 1 were used. Further, 1.0 g of a curing accelerator was used, and 498 g of a silica filler was used as an inorganic filler. Further, 0.5 g of carnauba wax as a release agent and 0.5 g of carbon black as a colorant were added and kneaded to obtain an epoxy resin composition. Using this epoxy resin composition, the molding temperature was 175 ° C. for 3 minutes. A cured product test piece was obtained under the condition of a post-cure temperature of 200 ° C. for 5 hours.

Examples 2-5, Comparative Examples 1-5
In the same manner as in Example 1, an epoxy resin, a modifier, a curing agent, an inorganic filler, a curing accelerator and other additives were kneaded at the blending ratios shown in Table 1 to prepare an epoxy resin composition. Then, the molding temperature was 175 ° C. for 3 minutes. A cured product test piece was obtained under the condition of a post-cure temperature of 200 ° C. for 5 hours. The numerical values in the table indicate the parts by weight in the formulation.

As is clear from these results, it was found that the epoxy resin composition obtained in the examples has both heat resistance having a glass transition temperature (Tg) of 200 ° C. or higher and high tracking resistance.

According to the present invention, an epoxy resin cured product having excellent tracking resistance, a balance with heat resistance, and excellent thermal decomposition stability can be obtained, and is suitable as a semiconductor encapsulation material, particularly an in-vehicle power semiconductor encapsulation material. is there.

Claims (6)

The following components (A) to (D);
(A) Aromatic epoxy resin represented by the following general formula (1),
(B) Modified selected from non-aromatic epoxy resin or non-silicone rubber having a 5% weight loss temperature of 260 ° C. or higher determined from TG / DTA measurement at a temperature rise rate of 10 ° C./min under a nitrogen stream. Pledge,
An epoxy resin composition containing (C) a curing agent and (D) a curing accelerator as essential components, and contains 1 to 50% by weight of the component (B) with respect to the total of the components (A) to (D). An epoxy resin composition characterized by

However, n represents a number from 0 to 20, and G represents a glycidyl group. The component (B) contains at least one epoxy resin selected from glycidyl esters of dihydric aliphatic carboxylic acids having 15 to 64 carbon atoms or glycidyl ethers of dihydric aliphatic alcohols having 15 to 64 carbon atoms. The epoxy resin composition according to claim 1, which is a modifier composed of a bifunctional epoxy resin. The epoxy resin composition according to claim 1, wherein the component (B) is a rubber-based modifier made of styrene-based rubber or acrylic-based rubber. The epoxy resin composition according to claim 2 or 3, wherein the component (C) is a curing agent containing a phenol resin represented by the following general formula (2).

However, R represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and m represents a number of 0 or 1. An epoxy resin cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 4. A semiconductor device in which a semiconductor element is sealed with the epoxy resin composition according to any one of claims 1 to 4.