JP7252196B2 - Epoxy resin composition and cured product thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition, an epoxy resin cured product, and a semiconductor device. The present invention relates to an epoxy resin composition suitable for semiconductor encapsulation, an epoxy resin cured product, and a semiconductor device.

Epoxy resins are used in a wide variety of industrial applications. One example is its use as a sealing material in semiconductor devices, but the required performance of semiconductor devices has become more and more sophisticated in recent years, and the required power density has become a difficult area to reach with conventional Si devices. . Under these circumstances, further increase in power density is expected, and SiC power devices can be cited as devices that have been developed in recent years. reaches over 200°C. Therefore, it is desired to develop a sealing material that can withstand such temperatures and maintain its physical properties for 1000 hours or longer.

In automotive semiconductor devices, in particular, the integration of various sensors and electronic control units for safety control is progressing. There is an increasing demand for materials that can withstand high temperature environments.

Furthermore, there is an increasing demand for not only thermal durability but also insulation performance due to higher voltages and higher currents. The circuit pitch width and distance between lead terminals are becoming smaller not only for power semiconductor devices used in high voltage applications such as automobiles, trains, wind power generation, and solar power generation, but also for 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 substrate material are required to have anti-tracking characteristics of 600 V or higher.

Methods to improve tracking resistance include 1) suppression of thermal/oxidative decomposition (increase in thermal decomposition initiation temperature, suppression of volatile gas content), and 2) improvement in electrical insulation at high temperatures (improvement in glass transition temperature). 3) Suppression of charring (reduction of residual coal rate, addition of inorganic filler), etc. are said to be effective, and various methods have been proposed. For example, a semiconductor device sealed with a silicone resin as a sealing material having high tracking resistance on the surface and excellent ease of workability (Patent Document 1), 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 phenol, a compound having a triazine ring, or a polycondensate of aldehydes (Patent Document 2), epoxidized cyclic conjugate A semiconductor chip sealing material containing a diene polymer as a resin component and optionally containing an inorganic filler and a conductive filler has been proposed (Patent Document 3). In addition, as a resin composition for semiconductor encapsulation excellent in tracking resistance, a resin composition for semiconductor encapsulation 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. (Patent Document 4), and an epoxy resin composition for semiconductor encapsulation (Patent Document 5) in which a metal hydroxide is added as an inorganic filler to an epoxy resin has been proposed, but the heat resistance is lowered. On the other hand, an epoxy resin composition for semiconductor encapsulation containing an epoxy resin, a curing agent, an inorganic filler and a spherical silicone powder (Patent Document 6) is disclosed, but this resin composition attempts to improve tracking resistance. not a thing Furthermore, the encapsulating resin composition containing silicone rubber powder (Patent Document 7) has excellent tracking properties, but does not have sufficient heat resistance. In addition, there is concern about the possibility of causing contact failures when low-molecular-weight components volatilize from silicone-based rubber powder. Epoxy resins, epoxy resin compositions, and cured products having a biphenol-biphenylaralkyl structure have already been disclosed as structures having excellent heat resistance, but tracking resistance is not described (Patent Document 8, Patent Documents). 9).

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

In the conventional technology, since tracking resistance, heat resistance, and flame retardancy are in a trade-off relationship, it has been difficult to achieve both heat resistance at 200° C. or higher and tracking resistance at 600V. Accordingly, the present invention provides an epoxy resin composition which is particularly excellent in tracking resistance, excellent in balance with heat resistance, and excellent in thermal decomposition stability, and which is particularly suitable for encapsulating power semiconductors. It is intended to provide a resin cured 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。The present invention provides the following components (A) to (D);
(A) an aromatic epoxy resin represented by the following general formula (1);
(B) A modifier selected from non-aromatic epoxy resins or non-silicone rubbers having a 5% weight loss temperature of 260° C. or higher as determined by TG/DTA measurement at a heating rate of 10° C./min under a nitrogen stream. pawn,
An epoxy resin composition comprising (C) a curing agent and (D) a curing accelerator as essential components, and containing 1 to 50% by weight of component (B) with respect to the total of components (A) to (D). It is an epoxy resin composition characterized by

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

As the component (B), at least one type of epoxy resin selected from glycidyl esters of divalent aliphatic carboxylic acids having 15 to 64 carbon atoms or glycidyl ethers of divalent aliphatic alcohols having 15 to 64 carbon atoms. A modifier consisting of a bifunctional epoxy resin, or a rubber-based modifier consisting 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 the 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 encapsulated with the above 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 achieve both tracking resistance and heat resistance, which are difficult with conventional techniques. In addition, the epoxy resin composition is excellent in fluidity and moldability, and its cured product is excellent in glass transition temperature of 200° C. or higher, long-term thermal stability, and flame retardancy. Furthermore, since it is non-silicone, it is suitable for in-vehicle use.

The present invention will be described in detail below.

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

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 represents a number of 0 or more, the average value (number average) is 1.3 to 20, preferably 1.5 to 15, more preferably 1.7 to 10, 2 to 6 is more preferred. Moreover, the content of the n=0 component where n is 0 is preferably 30 area % or less by gel permeation chromatography (GPC) measurement from the viewpoint of reactivity and fluidity. If the amount is more than that, the crystallinity becomes strong and the handling becomes difficult. In addition, when it is dissolved in an organic solvent for use as a laminated plate 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 or more components is 15 area % or more, preferably 20 area % or more, from the viewpoint of improving heat resistance. Also, 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 polyhydric hydroxy resin represented by the following general formula (3) with epichlorohydrin. Since this polyhydric hydroxy resin has a biphenyl structure, it is also called a biphenyl aralkyl type doxy resin. This biphenylaralkyl-type hydroxy resin is obtained by reacting a biphenol 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 used as starting materials for synthesizing biphenylaralkyl-type hydroxy resins include 4,4'-dihydroxybiphenyls.

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

The molar ratio in the reaction is preferably 1 mol or less of the biphenyl-based condensing agent per 1 mol of 4,4′-dihydroxybiphenyl, and generally in the range of 0.1 to 0.7 mol. It is preferably in the range of 0.2 to 0.5 mol. If the amount is less than this, the crystallinity becomes strong, the solubility in epichlorohydrin in synthesizing the epoxy resin is lowered, and the melting point of the resulting epoxy resin is increased, resulting in poor handleability. On the other hand, if the amount is more than this, the crystallinity of the resin is lowered, and the softening point and melt viscosity are increased, which impairs handling workability and moldability.

Moreover, when chloromethylbiphenyl is used as a condensing agent, the reaction can be carried out in the absence of a catalyst, but the condensation reaction is usually carried out in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from well-known inorganic acids and organic acids. Acids, organic acids such as trifluoromethosulfonic acid, Lewis acids such as zinc chloride, aluminum chloride, iron chloride and boron trifluoride, solid acids, and the like.

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

A method for producing the biphenylaralkyl-type epoxy resin represented by the general formula (1) by reacting the biphenylaralkyl-type hydroxy resin and epichlorohydrin will be described. This reaction can be carried out in a manner similar to well-known epoxidation reactions.

For example, after dissolving a biphenylaralkyl-type hydroxy resin in excess epichlorohydrin, it is dissolved in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at a temperature of 50 to 150°C, preferably 60 to 120°C for 1 to 1°C. A method of reacting for 10 hours can be mentioned. The amount of epichlorohydrin used in this case is in the range of 0.8 to 2.0 mol, preferably 0.9 to 1.2 mol, per 1 mol of hydroxyl groups in the polyhydroxy resin. After completion of the reaction, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered and washed with water to remove inorganic salts, and then the solvent is distilled off to obtain a compound of the general formula ( The desired epoxy resin represented by 1) can be obtained. A catalyst such as a quaternary ammonium salt may be used in the epoxidation reaction.

The purity of the biphenyl aralkyl type epoxy resin, particularly the amount of hydrolyzable chlorine, should be less from the viewpoint of improving the reliability of electronic components to which it is applied. Although not particularly limited, it is preferably 1000 ppm or less, more preferably 500 ppm or less. In addition, the hydrolyzable chlorine referred to in the present invention refers to the value measured by the following method. That is, after dissolving 0.5 g of the sample in 30 ml of dioxane, 10 ml of 1N-KOH was added and the mixture was boiled and refluxed for 30 minutes, cooled to room temperature, further 100 ml of 80% acetone water was added, and a potential difference was obtained with an aqueous 0.002N- _AgNO3 solution. It is a value obtained by titration.

The epoxy resin composition of the present invention may contain epoxy resins as other components in addition to the epoxy resin of component (A). The epoxy resin as another component is also called component (F).
Component (F) is preferably an aromatic epoxy resin obtained by epoxidizing a phenolic hydroxyl group.
As such epoxy resins, all ordinary aromatic epoxy resins having two or more epoxy groups in the molecule can be used. Examples include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, resorcin, naphthalene diols trihydric or higher epoxides of dihydric phenols such as tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolak, o-cresol novolak, etc. epoxidized phenols, epoxidized co-condensed resins obtained from dicyclopentadiene and phenols, epoxidized co-condensed resins obtained from cresols, formaldehyde and alkoxy group-substituted naphthalenes, phenols and paraxylylene dichloride Epoxidized products of phenol aralkyl resins obtained from, etc., epoxidized products of biphenyl aralkyl type phenol resins obtained from phenols and bischloromethylbiphenyl, etc., epoxidized products of naphthol aralkyl resins synthesized from naphthols and paraxylylene dichloride, etc. etc. These epoxy resins can be used singly or in combination of two or more. In addition, in the epoxy resin composition of the present invention, the amount of the epoxy resin represented by general formula (1) is preferably in the range of 5 to 100 wt%, preferably 60 to 100 wt% of the total epoxy resin. .

Component (B) is a non-silicone modifier selected from non-aromatic epoxy resins and non-silicone rubbers. The 5% weight loss temperature obtained from TG/DTA measurement is 260° C. or higher. This modifier acts as a modifier for improving tracking resistance.

When the modifier is blended, phase separation occurs in the resin, which is thought to suppress aggregation of the carbonized layer that occurs during thermal decomposition, and an 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 high temperatures of 200°C or higher.

Use of a non-silicone modifier as the modifier has the following advantages. Silicone-based modifiers such as silicone rubber are concerned about the possibility of causing contact failure when low-molecular-weight components volatilize. However, such problems are eliminated. 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 components (A) to (D).
From another point of view, it is preferably in the range of 1 to 50 parts by weight, preferably 2 to 30 parts by weight, per 100 parts by weight of the total resin component in the epoxy resin composition. If it is smaller than this, the effect of suppressing aggregation of the carbonized layer is low.

The modifier is preferably dispersed in a phase-separated state of 10 µm or less or in the form of particles. The particle diameter (median average diameter) is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 5 μm, 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 divalent aliphatic carboxylic acids having 15 to 64 carbon atoms and glycidyl ethers of divalent aliphatic alcohols having 15 to 64 carbon atoms. A bifunctional epoxy resin containing an epoxy resin as an essential component is preferred.
Rubbers made of styrene rubber or acrylic rubber are also excellent modifiers.

Examples of the divalent aliphatic carboxylic acid having 15 to 64 carbon atoms include 2-dodecylsuccinic acid, hexadecanedioic acid, 8-hexadecenedioic acid, 8,9-diethylhexadecanedioic acid, eicosanedioic acid, 7-vinyl Aliphatic dicarboxylic acids such as tetradecanedioic acid, 1,16-(6-ethylhexadecane)dicarboxylic acid, 1,18-(7,12-octadecadiene)dicarboxylic acid, 1,12-(diethyldodecane)dicarboxylic acid, , dimer acid whose main component is a dibasic acid with 36 carbon atoms obtained by the intermolecular reaction of two or more unsaturated fatty acids (linoleic acid, oleic acid, etc.), and water obtained by hydrogenating the dimer acid Dimer acid and the like may be mentioned, but it is not particularly limited. Epoxy resins of glycidyl esters of divalent aliphatic carboxylic acids having 15 to 64 carbon atoms can be obtained by diglycidyl esterifying these divalent aliphatic carboxylic acids using known epoxidation techniques.

Examples of dihydric aliphatic alcohols having 15 to 64 carbon atoms include long-chain aliphatic alcohols such as 1,15-pentadecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, and 1,19-nonadecanediol. polyethylene glycols such as diols, octaethylene glycol and nonaethylene glycol; polypropylene glycols such as pentapropylene glycol and hexapropylene glycol; and cyclocycles such as 4,4′-(propane-2,2-diyl)bis(cyclohexanol) Included diols, dimer diols obtained by reducing the carboxyl groups of the aforementioned dimer acids and hydrogenated dimer acids to hydroxyl groups, hydrogenated dimer diols, and the like, are not particularly limited. By diglycidyl etherifying 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 rubbers and acrylic-based rubbers include styrenes (including substituted styrenes), acrylics (acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, acrylonitrile, etc.) can be used. Diene rubbers such as non-silicone natural rubbers and butadiene rubbers can also be used.

Examples of styrene rubber include acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile chlorinated polyethylene styrene copolymer (ACS), acrylonitrile ethylene propylene rubber styrene copolymer (AES), 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), styrene ethylene butylene styrene block copolymer (SEBS), styrene ethylene propylene styrene block copolymer (SEPS), styrene isoprene styrene block copolymer (SIS), acrylonitrile styrene dimethyl siloxane alkyl acrylate copolymer, etc. is mentioned. In particular, from the viewpoint of reducing the elastic modulus and improving the impact resistance, styrene-butadiene copolymers (SB), methyl methacrylate-butadiene-styrene copolymers (MBS), acrylonitrile-styrene-dimethylsiloxane-alkyl acrylate copolymers, and other styrene and Rubbers obtained by copolymerization with monomers having saturated double bonds are preferred.

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

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

Polyhydric phenols include, for example, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, hydroquinone, resorcinol, catechol, biphenols, dihydric phenols such as naphthalene diols, and tris-(4-hydroxyphenyl ) Methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolak, o-cresol novolak, naphthol novolak, dicyclopentadiene type phenol resin, phenol aralkyl resin, etc. Phenols, further phenols, naphthols, or bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, catechol, naphthalene diols, etc. phenols and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, p-xylylene glycol dimethyl ether, divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyls, divinylbiphenyl, diisopropenylbiphenyls Biphenyl aralkyl type phenol resins obtained from phenols and bischloromethylbiphenyl, etc., Naphthol aralkyl resins synthesized from naphthols and paraxylylene dichloride, etc. etc.

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

By using the above aralkyl-type phenolic resin or a curing agent containing the same, a high Tg property of 200 ° C. or higher required for power device sealing materials was found, and long-term thermal stability was maintained by maintaining a glass state during a long-term heat resistance test. sexuality is expressed.

The aralkyl-type phenolic resin represented by 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 is determined by considering the equivalence balance between the epoxy groups in the epoxy resin and the active hydrogens (hydroxyl groups in the case of polyhydric phenols) in the curing agent. The equivalent ratio of epoxy resin and curing agent is usually in the range of 0.2 to 5.0, preferably in the range of 0.5 to 2.0, more preferably in the range of 0.8 to 1.5. is. If 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.

In addition to the aromatic hydroxy compound, another kind of curing agent may be blended in this epoxy resin composition as a curing agent component. Curing agents in this case include, for example, dicyandiamide, acid anhydrides, aromatic and aliphatic amines, and the like. One or two or more of these curing agents can be used in combination for the epoxy resin composition of the present invention.

Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl himic anhydride, dodecynylsuccinic anhydride, nadic anhydride, and trimellitic anhydride.

Amines include aromatic amines such as 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylsulfone, m-phenylenediamine and p-xylylenediamine, ethylenediamine, There are aliphatic amines such as hexamethylenediamine, diethylenetriamine and triethylenetetramine.

Component (D) is a curing accelerator for the epoxy resin composition. The curing accelerator may be one well known in the technical field of epoxy resins, 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, tris(dimethylaminomethyl)phenol; - imidazoles such as methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, tributylphosphine, methyldiphenylphosphine, triphenylphosphine, Organic phosphines such as diphenylphosphine and phenylphosphine, tetra-substituted phosphonium/tetra-substituted borate such as tetraphenylphosphonium/tetraphenylborate, tetraphenylphosphonium/ethyltriphenylborate, tetrabutylphosphonium/tetrabutylborate, 2-ethyl-4 tetraphenylboron 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, indene resin, indene-cumarone resin, phenoxy resin, etc. may be 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.

Additives such as inorganic fillers, pigments, flame retardants, thixotropic agents, coupling agents, fluidity improvers and the like can be added to the epoxy resin composition of the present invention. Examples of inorganic fillers include spherical or crushed fused silica, silica powder such as crystalline silica, alumina powder, glass powder, mica, talc, calcium carbonate, alumina, and hydrated alumina. When used as a sealing material, the blending amount is preferably 70% by weight or more, more preferably 80% by weight or more.

Pigments include organic or inorganic extender pigments, scaly pigments, and the like. Examples of thixotropic agents include castor oil, aliphatic amide wax, polyethylene oxide wax, and organic bentonite.

Furthermore, if necessary, the resin composition of the present invention may contain a releasing agent such as carnauba wax or OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a coloring agent such as carbon black, trioxide, or the like. Flame retardants such as antimony, lubricants such as calcium stearate, and the like can be used.

The epoxy resin composition of the present invention is partially or wholly dissolved in an organic solvent to form a varnish, and then impregnated into fibrous materials such as glass cloth, aramid nonwoven fabric, and polyester nonwoven fabric such as liquid crystal polymer, and then dissolved in a solvent. It can be removed and turned into a prepreg. When a solvent-insoluble matter such as an inorganic filler is contained, it is not necessary to dissolve it, but it is desirable to suspend it to form a gradual uniform solution. In some cases, a laminate can be obtained by coating a sheet-like material such as a copper foil, a stainless steel foil, a polyimide film, a polyester film, or the like.

By heat-curing the epoxy resin composition of the present invention, a cured epoxy resin can be obtained, and the cured product is excellent in terms of low moisture absorption, high heat resistance, adhesion, flame retardancy, and the like. Become. A cured product can be obtained by molding an 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 as a sealing material. Also, the semiconductor device of the present invention is 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 to these. "Parts" means parts by weight and "%" means % by weight unless otherwise specified. Moreover, the measurement method was each measured by the following methods.

1) Measurement of Epoxy Equivalent A potentiometric titrator was used, chloroform was used as a solvent, a tetraethylammonium bromide acetate solution was added, and a 0.1 mol/L perchloric acid-acid solution was used for measurement with a potentiometric titrator.

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

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

4) Total chlorine After dissolving 1.0 g of sample in 25 ml of butyl carbitol, adding 25 ml of 1N-KOH propylene glycol solution and heating under reflux for 10 minutes, cooling to room temperature, further adding 100 ml of 80% acetone water and adding 0.002 N —Measured by performing potentiometric titration with an aqueous AgNO ₃ solution.

5) GPC Measurement A column (TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL, manufactured by Tosoh Corporation) in series with a main body (HLC-8220GPC manufactured by Tosoh Corporation) was used, and the column temperature was set to 40°C. Tetrahydrofuran (THF) was used as an eluent at a flow rate of 1 mL/min, and a differential refractive index detector was used as a detector. As a measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF and filtered through a microfilter, and 50 μL of the solution 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 with a thermomechanical measurement device (EXSTAR6000TMA/6100 manufactured by SII Nanotechnology Co., Ltd.) under the condition of a temperature increase rate of 10°C/min.

7) 5% weight loss temperature (Td5), residual carbon ratio Using a thermogravimetric/differential thermal analyzer (EXSTAR6000TG/DTA6200 manufactured by SII Nanotechnology Co., Ltd.), under a nitrogen atmosphere, at a heating rate of 10 ° C./min. , the 5% weight loss temperature (Td5) was measured.
Also, the weight loss at 700°C was measured under the above conditions, and the weight loss was converted to the resin component excluding the inorganic filler, thereby calculating the residual carbon content of the resin component at 700°C.

8) PTI value (600V)
Based on IEC60112, a cured resin product (20×20×3 mm) was used as a test piece and tested. The electrode was made of platinum and had a tip angle of 30 degrees. A 0.1% ammonium chloride solution was used as the electrolyte. After conditioning the test piece at 23° C. and 50% RH for 8 hours, apply a voltage of 600 V in an environment of 23° C. and 50% RH, drop the electrolyte, and cause tracking breakdown on the test surface. The number of drips up to was calculated. Also, the test was conducted 5 times, and the number of droplets that did not cause tracking destruction even after exceeding 50 droplets at 600V was measured. HAT-112-3 manufactured by Yamayo Test Instruments Co., Ltd. was used as a measuring device.

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 were placed in a 1000 ml four-necked flask, and the temperature was raised to 170° C. under a nitrogen stream with stirring. It was warmed and reacted for 20 hours. After the reaction, 46.4 g of diethylene glycol dimethyl ether was recovered. 446.5 g of epichlorohydrin was added to this reaction mixture, and 69.4 g of a 48% aqueous sodium hydroxide solution was added dropwise at 62° C. under reduced pressure (about 130 Torr) over 4 hours. During this time, the generated water was removed from the system by azeotroping with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropwise addition was completed, the reaction was further continued for 1 hour. Thereafter, epichlorohydrin was distilled off, methyl isobutyl ketone was added, the salt was removed by washing with water, and after filtration and washing with water, methyl isobutyl ketone was distilled off under reduced pressure to obtain 141 g of an epoxy resin (epoxy resin 1). . The epoxy equivalent of this epoxy resin was 198. The DSC measurement result of this epoxy resin showed a peak temperature of 126°C and a melt viscosity of 0.25 Pa·s at 150°C.

Synthesis example 2
A 1 L four-necked flask was charged with 500 g of phenol (8.0 times the moles of dicyclopentadiene) and 9.5 g of boron trifluoride etherate as an acid catalyst, and the temperature was raised to 120°C. Next, 88 g of dicyclopentadiene was added dropwise over 6 hours while stirring at 120° C. to cause a reaction, followed by aging at 130° C. for 4 hours, followed by neutralization and recovery of phenol. Subsequently, the product was dissolved in 300 g of MIBK, washed with water at 80° C. four times, and MIBK was distilled off under reduced pressure to obtain 179 g of polyhydric hydroxy compound. Its hydroxyl 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-necked separable flask and dissolved with stirring. After uniformly dissolving, the temperature was maintained at 65°C under a reduced pressure of 130 mmHg, and 68.2 g of a 48% sodium hydroxide aqueous solution was added dropwise over 4 hours. It was returned to the reaction vessel, water was removed from the system, and the reaction was carried out. After completion of the reaction, the salt produced was removed by filtration, and after further washing with water, 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
Dimer diol (CRODA Pripol 20
33, hydroxyl equivalent 270 g/eq. ) 300.0 g, 308.3 g of epichlorohydrin, 120.0 g of toluene, and 6.2 g of water were charged, and the temperature was raised to 50° C. with stirring under a nitrogen stream to dissolve them. After dissolution, 6.0 g of benzyltrimethylammonium chloride was added, and 13.6 g of 95.5% solid potassium hydroxide was added in portions over 2 hours. After further reacting for 2.5 hours, 300 g of toluene and 387.5 g of water were added, the salt produced by liquid separation was removed, epichlorohydrin, toluene and water were distilled off, and 543.2 g of toluene was added and dissolved at 80°C. . Thereafter, 12.3 g of a 48.8% aqueous potassium hydroxide solution was added to carry out a purification reaction. After neutralization, washing with water, and filtration, toluene was distilled off to obtain 325.9 g of modifier a, which is a liquid epoxy resin. . The epoxy equivalent of modifier a is 360 g/eq. , the viscosity at 25° C. was 243 Pa·s. Moreover, Td5 was 324 degreeC.

Abbreviations used in the examples are explained below.
(Epoxy resin)
Epoxy resin 1: Epoxy resin obtained in Synthesis Example 1 Epoxy resin 2: o-cresol novolak epoxy resin (epoxy equivalent: 200, softening point: 65°C, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Epoxy resin 3; epoxy resin obtained in Synthesis Example 3 (modifier)
Modifier a: Modifier obtained in Synthesis Example 4 Modifier b: ABA structure radical-controlled polymerized acrylic block copolymer (NANOSTRENGTH M51, Arkema 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.)
(curing agent)
Curing agent 1: Triphenolmethane type polyhydric hydroxy resin (TPM-100, manufactured by Gunei Chemical Industry Co., Ltd., OH equivalent 97.5, softening point 105°C)
Curing agent 2: Phenol novolac type polyhydric hydroxy resin (BRG-557, manufactured by Gunei Chemical Industry Co., Ltd., OH equivalent 105, softening point 80°C)
(Curing accelerator)
2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW, manufactured by Shikoku Kasei)
(others)
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 epoxy resin components, 64.0 g of epoxy resin 1 obtained in Synthesis Example 1, 5.1 g of modifier a, and 32.9 g of curing agent 1 were used. Also, 1.0 g of a curing accelerator was used, and 498 g of silica filler was used as an inorganic filler. Further, 0.5 g of carnauba wax as a releasing agent and 0.5 g of carbon black as a coloring agent were added and kneaded to obtain an epoxy resin composition. Using this epoxy resin composition, molding temperature 175° C., 3 minutes. A cured product test piece was obtained under the conditions of a post-curing temperature of 200° C. and 5 hours.

Examples 2-5, Comparative Examples 1-5
In the same manner as in Example 1, an epoxy resin composition was prepared by kneading an epoxy resin, a modifier, a curing agent, an inorganic filler, a curing accelerator, and other additives in the proportions shown in Table 1. Then, molding temperature 175° C., 3 minutes. A cured product test piece was obtained under the conditions of a post-curing temperature of 200° C. and 5 hours. The numerical values in the table indicate parts by weight in the compounding.

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

According to the present invention, a cured epoxy resin product having excellent tracking resistance, well-balanced heat resistance, and excellent thermal decomposition stability can be obtained. be.

Claims (4)

the following components (A) to (D);
(A) an aromatic epoxy resin represented by the following general formula (1);
(B) Glycidyl of a divalent aliphatic carboxylic acid having 15 to 64 carbon atoms and having a 5% weight loss temperature of 260° C. or higher as determined by TG/DTA measurement at a heating rate of 10° C./min under a nitrogen stream. a bifunctional epoxy resin containing at least one type of epoxy resin selected from esters or glycidyl ethers of dihydric aliphatic alcohols having 15 to 64 carbon atoms, or a modifier selected from styrene rubber or acrylic rubber;
An epoxy resin composition comprising (C) a curing agent and (D) a curing accelerator as essential components, and containing 1 to 50% by weight of component (B) with respect to the total of components (A) to (D). An epoxy resin composition characterized by:

However, n is the number of repetitions and indicates a number of 0 or more, and its average value is 1.3-20. G represents a glycidyl group. 2. The epoxy resin composition according to claim 1 , wherein the component (C) is a curing agent containing a phenolic 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 the number of 0 or 1. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 1 . A semiconductor device in which a semiconductor element is encapsulated with the epoxy resin composition according to claim 1 .