JP2017088634A - Epoxy resin composition, method for producing epoxy resin cured product, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition that can produce a cured product excellent in heat resistance, thermal decomposition stability, and mechanical strength retention as well as is excellent in flowability during molding, and is suitable for use as a power device encapsulating material, and to provide a method for producing epoxy resin cured product.SOLUTION: Provided are: an epoxy resin composition containing an epoxy resin represented by the general formula (1), a phenol type curing agent, a curing catalyst, and an inorganic filler and having an exothermic peak top of 150°C or higher when subjected to differential scanning calorimetry measurement under a condition of a temperature rise rate of 10°C/min; and also a method for producing an epoxy resin cured product which is formed by molding the epoxy resin composition at 100°C to 200°C, followed by post-cure at 200°C to 300°C. (Here, n represents an average value of 0.2 to 4.0, and G represents a glycidyl group.).SELECTED DRAWING: None

Description

  The present invention relates to an epoxy resin composition, a method for producing an epoxy resin cured product, and a semiconductor device. More specifically, an epoxy resin cured product having excellent heat resistance and thermal decomposition stability is obtained, and fluidity during molding is provided. In particular, the present invention relates to an epoxy resin composition suitable for power semiconductor sealing, a method for producing a cured epoxy resin, and a semiconductor device.

  Epoxy resins are used in a wide range of industrial applications. As an example, there is an application as a sealing material in a semiconductor device, but the required performance in the semiconductor device has become increasingly sophisticated in recent years, and the required power density has become a region that is difficult to reach with conventional Si devices. . Under such circumstances, SiC power devices can be cited as devices that are expected to have higher power density and are being developed in recent years. To achieve higher power density, the temperature of the chip surface during operation Reaches 250 ° C. Therefore, development of a sealing material that can withstand the temperature and can maintain the physical properties for 1000 hours or more is strongly desired.

  Under such circumstances, Patent Documents 1 and 2 disclose an epoxy resin, an epoxy resin composition, and a cured product having a biphenol-phenylaralkyl structure, and are excellent in heat resistance, moisture resistance, and thermal conductivity. It is shown. However, even when the epoxy resin disclosed in Patent Document 1 is used as described above, when a phenol novolak is used as a curing agent by a normal molding method, only a cured product having a glass transition temperature (Tg) of about 200 ° C. Not obtained. Therefore, the subject that the characteristic of the sealing material for high heat resistant SiC power devices which can endure a high operating temperature of 250 degreeC cannot be satisfied occurred. Moreover, in patent document 1, long-term thermal stability required for the sealing material for SiC power devices is not described.

Japanese Patent Laid-Open No. 11-60687 Japanese Patent Laid-Open No. 10-292032

  Accordingly, an object of the present invention is to obtain an epoxy resin cured product excellent in high Tg property (heat resistance), weight retention property (thermal decomposition stability) at high temperature and long term, and mechanical strength retention property, and molding. Another object of the present invention is to provide an epoxy resin composition that is excellent in fluidity and suitable for use as a power device sealing material. Another object of the present invention is to provide a method for producing a cured epoxy resin such as a power device encapsulant by using this epoxy resin composition.

（但し、ｎは平均値として０．２〜４．０を示し、Ｇはグリシジル基を示す。） That is, the present invention is an epoxy resin composition containing an epoxy resin represented by the following general formula (1), a phenolic curing agent, a curing catalyst, and an inorganic filler, and the temperature of the epoxy resin composition is increased. An epoxy resin composition characterized by having an exothermic peak top of 150 ° C. or higher when differential scanning calorimetry is performed at a rate of 10 ° C./min.

(However, n represents an average value of 0.2 to 4.0, and G represents a glycidyl group.)

  The present invention is the epoxy resin composition as described above, wherein the curing catalyst is at least one selected from the group consisting of imidazoles, organic phosphines, and amines.

（但し、Ｒは水素原子又は炭素数１〜６の炭化水素基を示し、ｌは０又は１の数を示す。）

（但し、Ａはベンゼン環、ナフタレン環又はビフェニル環を示し、ｋは１〜１５の数、ｍ及びpはそれぞれ１又は２の数を示す。） Moreover, this invention is an epoxy resin composition as described above in which a phenol type hardening | curing agent is represented by the following general formula (2) or (3).

(However, R shows a hydrogen atom or a C1-C6 hydrocarbon group, and l shows the number of 0 or 1.)

(However, A shows a benzene ring, a naphthalene ring, or a biphenyl ring, k shows the number of 1-15, m and p show the number of 1 or 2, respectively.)

（但し、ｎは平均値として０．２〜４．０を示し、Ｇはグリシジル基を示す。） In addition, the present invention contains an epoxy resin represented by the following general formula (1), a phenolic curing agent, a curing catalyst, and an inorganic filler, and was subjected to differential scanning calorimetry at a temperature rising rate of 10 ° C./min. An epoxy resin composition having an exothermic peak top of 150 ° C. or higher is molded at a molding temperature of 100 ° C. to 200 ° C. and then post-cured at 200 ° C. to 300 ° C. Is the method.

(However, n represents an average value of 0.2 to 4.0, and G represents a glycidyl group.)

  The cured epoxy resin obtained above is suitable for a power semiconductor encapsulant. Furthermore, the present invention is a semiconductor device characterized in that a power semiconductor element is sealed with the cured epoxy resin.

  The cured epoxy resin obtained using the poxy resin composition of the present invention is excellent in high Tg property, weight retention at high temperature and long term, and mechanical strength retention. Excellent fluidity. Therefore, the epoxy resin composition of this invention can be used conveniently for the use of the sealing material of a power semiconductor.

  Hereinafter, the present invention will be described in detail.

（但し、ｎは平均値として０．２〜４．０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 represented by the general formula (1), which is an essential component of the epoxy resin composition of the present invention, reacts a polyvalent hydroxy resin represented by the following general formula (a) with epichlorohydrin. Can be manufactured. And this polyhydric hydroxy resin can be manufactured by making biphenols and the phenyl-type condensing agent represented by the following general formula (b) react.

(However, n represents an average value of 0.2 to 4.0.)

(However, X shows a hydroxyl group, a halogen atom, or a C1-C6 alkoxy group.)

  Examples of the biphenols used as a raw material for synthesizing the polyvalent hydroxy resin include dihydroxybiphenyls such as 4,4'-dihydroxybiphenyl and 2,2'-dihydroxybiphenyl. These bifunctional phenolic compounds may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. Examples of the substituent include a methyl group, an ethyl group, an isopropyl group, an allyl group, a tertiary butyl group, an amyl group, a cyclohexyl group, and a phenyl group. These dihydroxybiphenyls may be used alone or in combination of two or more.

  In the general formula (b), X represents a hydroxyl group, a halogen atom or an alkoxy group having 1 to 6 carbon atoms. The phenyl-based condensing agent of the general formula (b) may be any of o-, m-, and p-forms, preferably m-forms and p-forms. Specifically, p-xylylene glycol, α, α′-dimethoxy-p-xylene, α, α′-diethoxy-p-xylene, α, α′-diisopropyl-p-xylene, α, α′-dibutoxy -P-xylene, m-xylylene glycol, α, α'-dimethoxy-m-xylene, α, α'-diethoxy-m-xylene, α, α'-diisopropoxy-m-xylene, α, α ' -Dibutoxy-m-xylene etc. are mentioned.

  The molar ratio in the reaction is, for example, 1 mol or less of the phenyl condensing agent per mol of 4,4′-dihydroxybiphenyl, and is generally in the range of 0.1 to 0.7 mol. More preferably, it is the range of 0.2-0.5 mol. If it is less than this, the crystallinity becomes strong, the solubility in epichlorohydrin when synthesizing the epoxy resin is lowered, the melting point of the obtained epoxy resin is increased, and the handleability is lowered. On the other hand, if the amount is larger 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.

  In addition, when p-xylylene glycol is used as the condensing agent, the reaction can be carried out in the absence of a catalyst, but usually the condensation reaction is carried out in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from known inorganic acids and organic acids. For example, mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, metasulfone Examples thereof include organic acids such as acid and trifluorometasulfonic acid, 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 20 hours. In the reaction, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve and ethyl cellosolve, and aromatic compounds such as benzene, toluene, chlorobenzene and dichlorobenzene can be used as a solvent. . After completion of the reaction, the solvent or water and alcohol produced by the condensation reaction are removed as necessary.

  The method for producing the epoxy resin of the present invention by the reaction between the polyvalent hydroxy resin represented by the general formula (a) and epichlorohydrin will be described. This reaction can be performed in the same manner as a well-known epoxidation reaction.

  For example, after the polyvalent hydroxy resin represented by the general formula (a) is dissolved in excess epichlorohydrin, it is 50 to 150 ° C., preferably 60 in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The method of making it react for 1 to 10 hours in the range of -120 degreeC is mentioned. In this case, the amount of epichlorohydrin used is in the range of 0.8 to 2 mol, preferably 0.9 to 1.2 mol, relative to 1 mol of the hydroxyl group in the polyvalent hydroxy resin. Excess epichlorohydrin was distilled off after completion of the reaction, 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 to remove the general formula ( The target epoxy resin represented by 1) can be obtained. When performing the epoxidation reaction, a catalyst such as a quaternary ammonium salt may be used.

The purity of the epoxy resin of the present invention, in particular the amount of hydrolyzable chlorine, is better from the viewpoint of improving the reliability of the applied electronic component. Although it does not specifically limit, Preferably it is 1000 ppm or less, More preferably, it is 500 ppm or less. In addition, the hydrolyzable chlorine as used in the field of this invention means the value measured by the following method. That is, the potential difference the sample 0.5g were dissolved in dioxane 30 ml, 1N-KOH, after the added boiled under reflux for 30 minutes 10 ml, cooled to room temperature, 80% aqueous acetone 100ml was added, with 0.002 N-AgNO ₃ aqueous solution This is a value obtained by titration.

  Next, the epoxy resin composition of the present invention will be described. The epoxy resin composition of this invention contains the epoxy resin of the said General formula (1), a phenol type hardening | curing agent, a curing catalyst, and an inorganic filler.

  As a curing catalyst to be blended in this epoxy resin composition, a curing catalyst having an active site in a high temperature region in the epoxy resin composition (high temperature active catalyst) for the purpose of promoting curing and improving fluidity during molding. Is preferably used.

  The content of the curing catalyst is preferably in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin. Preferably it is 0.5-3 weight part, More preferably, it is 0.5-2.5 weight part. If it is smaller than this, the curability will be lowered, and conversely if it is larger than this, the fluidity improving effect at the time of molding will not be sufficiently exhibited.

  The DSC exothermic peak temperature of the epoxy resin composition using the high-temperature active catalyst is 150 ° C or higher, preferably 155 ° C or higher, more preferably 165 ° C or higher. When the exothermic peak temperature is lower than 150 ° C., the curing reaction proceeds at the time of molding, and the effect of improving fluidity is not sufficiently exhibited. This DSC exothermic peak temperature is the maximum exothermic peak (exothermic heat) when differential scanning calorimetry (DSC measurement) is performed on an epoxy resin composition containing a high-temperature active catalyst as a curing catalyst at a temperature rising rate of 10 ° C / min. This is a temperature indicating a peak top. In addition, the upper limit of the DSC exothermic peak temperature is substantially 300 ° C. considering that the curing temperature range by post-cure is preferably 200 ° C. to 300 ° C.

  Examples of the curing catalyst (high temperature active catalyst) include imidazoles, organic phosphines, amines and the like. Examples of imidazoles include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-heptadecylimidazole, and 2,4-diamino-6- [2′-dimethyl. Imidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4- Examples of organic phosphines such as diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine include tris- (2,6-dimethoxyphenyl) phosphine, tri-p-tolylphosphine, Examples of amines such as tris (p-chlorophenyl) phosphine and tris (p-methoxyphenyl) phosphine include 1,8-dia Bicyclo (5,4,0) phenol novolak salts of undecene-7 can be mentioned. One or two or more of these may be used in combination.

  In the present invention, by using a high-temperature active catalyst having a specific active temperature region as a curing catalyst, it is possible to suppress a decrease in fluidity. Further, regarding the curing conditions, particularly when the epoxy resin of the present invention is used. In addition, it has been found that the curing conditions at high temperature greatly affect the glass transition temperature.

  Moreover, a phenol type hardening | curing agent is used as a hardening | curing agent. In fields where high electrical insulation is required, such as semiconductor encapsulants, polyhydric phenols are preferably used as curing agents. Below, the specific example of a hardening | curing agent is shown.

  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). ) Trivalent or higher typified by methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, naphthol novolak, dicyclopentadiene type phenol resin, phenol aralkyl resin, etc. There are phenols. Furthermore, divalent phenols such as phenols, naphthols or bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, catechol, naphthalenediols, etc. Of formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, p-xylylene glycol dimethyl ether, divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyls, divinylbiphenyl, diisopropenylbiphenyls, etc. Polyphenolic compounds synthesized by reaction with chemicals, biphenyl aralkyl type phenols obtained from phenols and bischloromethylbiphenyl, etc. Resin. Furthermore, naphthol aralkyl resins synthesized from naphthols and paraxylylene dichloride are exemplified.

ここで、Ｒは水素原子又は炭素数１〜６の炭化水素基を示し、ｌは０〜２の数を示す。

ここで、Ａはベンゼン環、ナフタレン環、又はビフェニル環を示し、ｍおよびpは独立に１または２の数を示す。ここで、ベンゼン環、ナフタレン環、又はビフェニル環は、置換基を有するものであってもよく、好ましい置換基は炭素数が１〜３のアルキル基である。ｋは繰り返し数であり１〜１５の数であるが、その平均は１〜２の範囲であることが好ましい。 Among these, a preferable phenolic curing agent is preferably an aralkyl type phenol resin represented by the following general formula (2) or (3).

Here, R shows a hydrogen atom or a C1-C6 hydrocarbon group, and l shows the number of 0-2.

Here, A represents a benzene ring, a naphthalene ring, or a biphenyl ring, and m and p independently represent a number of 1 or 2. Here, the benzene ring, naphthalene ring, or biphenyl ring may have a substituent, and a preferable substituent is an alkyl group having 1 to 3 carbon atoms. k is the number of repetitions and is a number from 1 to 15, but the average is preferably in the range of 1 to 2.

  By using the curing agent represented by the general formula (2), a high Tg property of 250 ° C. or higher required for a power device sealant is found, and a high thermal decomposition is achieved by maintaining a glass state during a long-term heat test. Stability is expressed. Further, by using the curing agent represented by the general formula (3), particularly excellent weight retention and bending strength retention are exhibited by the introduction of a biphenyl structure having excellent thermal stability.

  The polyvalent hydroxy compound (phenolic curing agent) represented by the general formula (2) can be produced by reacting salicylaldehyde or p-hydroxyaldehyde with a phenolic hydroxyl group-containing compound.

  Here, as the phenolic hydroxyl group-containing compound, phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 4-ethylphenol, 2-propylphenol, 4-propylphenol, 4-tert-butylphenol 4-pentylphenol, 4-tert-pentylphenol, 4-neopentylphenol, 2-cyclopentylphenol, 2-hexylphenol, 4-hexylphenol, and the like.

  On the other hand, the polyvalent hydroxy compound (phenolic curing agent) represented by the general formula (3) can be produced by reacting a phenolic hydroxyl group-containing compound having a benzene ring or a naphthalene ring with an aromatic crosslinking agent.

  Here, as the phenolic hydroxyl group-containing compound, phenol, hydroquinone, resorcin, catechol, pyrogallol, phloroglucinol, 1-naphthol, 2-naphthol, 1,5-naphthalenediol, 1,6-naphthalenediol, 1,7 -Naphthalenediol, 2,6-naphthalenediol, 2,7-naphthalenediol, 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl and the like.

  Aromatic crosslinking agents include those having a benzene skeleton and those having a biphenyl skeleton. Those having a benzene skeleton may be any of o-, m- and p-forms, preferably m-forms and p-forms. Specifically, p-xylylene glycol, α, α′-dimethoxy-p-xylene, α, α′-diethoxy-p-xylene, α, α′-diisopropyl-p-xylene, α, α′-dibutoxy -P-xylene, m-xylylene glycol, α, α'-dimethoxy-m-xylene, α, α'-diethoxy-m-xylene, α, α'-diisopropoxy-m-xylene, α, α ' -Dibutoxy-m-xylene etc. are mentioned. Examples of those having a biphenyl skeleton include 4,4′-dihydroxymethylbiphenyl, 2,4′-dihydroxymethylbiphenyl, 2,2′-dihydroxymethylbiphenyl, 4,4′-dimethoxymethylbiphenyl, and 2,4 ′. -Dimethoxymethylbiphenyl, 2,2'-dimethoxymethylbiphenyl, 4,4'-diisopropoxymethylbiphenyl, 2,4'-diisopropoxymethylbiphenyl, 2,2'-diisopropoxymethylbiphenyl, 4,4 Examples include '-dibutoxymethylbiphenyl, 2,4'-dibutoxymethylbiphenyl, 2,2'-dibutoxymethylbiphenyl, and the like. The substitution position of a functional group such as a methylol group with respect to biphenyl may be any of 4,4′-position, 2,4′-position, and 2,2′-position, but a desirable compound as a condensing agent is 4,4′-position. It is particularly preferable that the total crosslinking agent contains 50 wt% or more of the 4,4′-isomer. If it is less than this, the curing rate as an epoxy resin curing agent will decrease, or the resulting cured product will be brittle.

  In the general formula (3), k is a number from 1 to 15. The value of k can be easily prepared by changing the molar ratio between the phenolic hydroxyl group-containing compound and the crosslinking agent when they are reacted. That is, the value of k can be controlled smaller as the phenolic hydroxyl group-containing compound is used in excess relative to the crosslinking agent. The larger the value of k, the higher the softening point and viscosity of the obtained resin. Further, the smaller the value of k, the lower the viscosity. However, the amount of unreacted phenolic hydroxyl group-containing compound at the time of synthesis increases, and the production efficiency of the resin decreases. Practically, the molar ratio of the crosslinking agent must be 1 mol or less, preferably 0.1 to 0.9 mol per mol of the phenolic hydroxyl group-containing compound. When the amount is less than 0.1 mol, the amount of unreacted phenolic hydroxyl group-containing compound is increased, which is not industrially preferable.

  The amount of the phenolic curing agent in the epoxy resin composition is blended in consideration of the equivalent balance between the epoxy group in the epoxy resin represented by the general formula (1) and the hydroxyl group of the phenolic curing agent. The equivalent ratio of the epoxy resin and the curing agent is usually in the range of 0.2 to 5.0, preferably 0.5 to 2.0, with the phenolic curing agent of the above general formula (2) or (3). More preferably, it is the range of 0.8-1.5. If it is larger or smaller than this, the curability of the epoxy resin composition is lowered, and the heat resistance, mechanical strength and the like of the cured product are lowered.

  Moreover, in this epoxy resin composition, you may mix | blend another hardening | curing agent in addition to a phenol type hardening | curing agent as a hardening | curing agent component. Examples of the curing agent in this case include dicyandiamide, acid anhydrides, aromatic and aliphatic amines, and one or more of these curing agents can be used in combination. However, the amount of the curing agent other than the phenol-based curing agent represented by the general formula (2) or (3) is preferably 50 wt% or less of the total curing agent.

  The compounding amount of the epoxy resin represented by the general formula (1) in the epoxy resin composition may be 0.1 wt% to 28 wt%, and preferably 3 wt% to 16 wt%. If the blending amount of the epoxy resin of the general formula (1) is less than 0.1 wt%, the heat resistance and thermal decomposition stability of the cured product is not sufficiently improved. Conversely, if it exceeds 28 wt%, the equivalent balance of epoxy group and hydroxyl group The heat resistance, mechanical strength, etc. of the cured product are reduced.

  Moreover, in this epoxy resin composition, you may mix | blend another epoxy resin in addition to the epoxy resin represented by General formula (1) as an epoxy resin component. As the epoxy resin in this case, all ordinary 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, naphthalenediols Trivalent or higher epoxides such as divalent phenols such as tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, etc. Epoxidized products of phenols, epoxidized products of cocondensation resins obtained from dicyclopentadiene and phenols, epoxidized products of cocondensation resins obtained from cresols, formaldehyde and alkoxy-substituted naphthalenes, phenols and paraxylylene dichloride Obtained from etc. E Nord aralkyl resin epoxidized product, there phenols and bis-chloromethyl biphenyl biphenyl aralkyl type phenolic resins obtained from the epoxy compound, epoxidized naphthol aralkyl resin and the like which are synthesized from naphthols and para-xylylene dichloride and the like. These epoxy resins can be used alone or in combination of two or more. However, the compounding quantity of the epoxy resin represented by General formula (1) is 5-100 wt% in the whole epoxy resin, Preferably it is the range of 60-100 wt%.

  As the inorganic filler, for example, silica powder such as spherical or crushed fused silica, crystalline silica, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, hydrated alumina, boron nitride, aluminum nitride, Examples thereof include silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, and magnesium oxide. As the compounding amount of the inorganic filler in the epoxy resin composition, the preferable compounding amount particularly when used for the semiconductor sealing material is 70% by weight to 95% by weight, and more preferably 80% by weight to 90% by weight. .

  The epoxy resin composition of the present invention may further include a release agent such as carnauba wax and OP wax, a coupling agent such as 4-aminopropylethoxysilane and γ-glycidoxypropyltrimethoxysilane, carbon, if necessary. A colorant such as black, a flame retardant such as antimony trioxide, and a lubricant such as calcium stearate may be blended.

  Further, in the epoxy resin composition of the present invention, an oligomer or a polymer compound such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene coumarone resin, phenoxy resin or the like is used as a modifier. You may mix | blend suitably. In this case, the addition amount is usually in the range of 2 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin.

  The epoxy resin composition of the present invention can also contain additives such as pigments, refractory agents, thixotropic agents, coupling agents, fluidity improvers, and antioxidants.

  Among these, examples of the pigment include organic or inorganic extender pigments and scaly pigments. Examples of the thixotropic agent include silicon-based, castor oil-based, aliphatic amide wax, polyethylene oxide wax, and organic bentonite.

  The epoxy resin composition of the present invention is made into a varnish in which an organic solvent is dissolved, and then impregnated into a fibrous material such as glass cloth, aramid nonwoven fabric, polyester nonwoven fabric such as liquid crystal polymer, and the like, and then the solvent is removed. It can be. Moreover, it can be set as a laminated body by apply | coating on sheet-like materials, such as copper foil, stainless steel foil, a polyimide film, and a polyester film depending on the case.

  Any method may be used for preparing the epoxy resin composition of the present invention as long as various raw materials can be uniformly dispersed and mixed. As a general method, raw materials of a predetermined blending amount are sufficiently mixed by a mixer or the like. Then, a method of melt-kneading with a mixing roll, an extruder or the like, cooling, and pulverizing can be mentioned.

  The epoxy resin composition and its cured product of the present invention are particularly suitable for sealing power semiconductor devices.

  The cured product of the present invention can be obtained by thermally curing the epoxy resin composition. In order to obtain a cured product using the epoxy resin composition of the present invention, for example, methods such as transfer molding, press molding, cast molding, injection molding, and extrusion molding are applied, but from the viewpoint of mass productivity. Transfer molding is preferred.

  As a curing method of the epoxy resin composition of the present invention, after molding at 100 ° C. to 200 ° C., preferably 120 ° C. to 190 ° C., more preferably 150 to 180 ° C., 200 ° C. to 300 ° C., preferably 220 ° C. to 280 ° C. More preferably, it is produced by post-curing at 230 to 270 ° C., and a cured product excellent in terms of Tg, high temperature long-term weight retention, mechanical strength retention and the like can be obtained. The Tg of the cured product is preferably 200 ° C. or higher, more preferably 250 ° C. or higher. Since a power semiconductor operates at an operating temperature exceeding 200 ° C., a sealing material having a Tg of less than 200 ° C. cannot be sufficiently sealed and has no durability.

  The molding time is preferably 1 to 60 minutes, more preferably 1 to 10 minutes. If the molding time is long, the productivity will be poor, and if it is too short, it will be difficult to release. The post cure time is preferably 10 minutes to 10 hours, preferably 30 minutes to 8 hours, and particularly preferably 2 hours to 6 hours. When the post-cure time is short, curing does not proceed sufficiently, and sufficient characteristics such as heat resistance and mechanical properties cannot be obtained. Moreover, productivity will fall when it exceeds 10 hours.

  In the epoxy resin composition of the present invention, the curing reaction proceeds even in a high post-cure temperature region where a general epoxy resin composition cannot react, and has a very high Tg, high temperature long-term weight retention, and mechanical strength retention. A cured product having properties and the like can be obtained.

  Hereinafter, based on a synthesis example, an Example, and a comparative example, this invention is demonstrated concretely.

Synthesis example 1
In a 2 L 4-neck flask, 186 g (1.0 mol) of 4,4′-dihydroxybiphenyl, 69 g (0.5 mol) of p-xylylene glycol, 743 g of diethylene glycol dimethyl ether, and 2.55 g of p-toluenesulfonic acid as an acid catalyst The temperature was raised to 160 ° C. Next, it was made to react for 3 hours, stirring at 160 degreeC. Next, after diethylene glycol dimethyl ether was partially distilled off under reduced pressure, 740 g of epichlorohydrin was charged and dissolved. Subsequently, 155.0 g of a 48% aqueous sodium hydroxide solution was added dropwise at 75 ° C. under reduced pressure over 4 hours, and water and epichlorohydrin refluxed during the dropping were separated in a separation tank, and epichlorohydrin was returned to the reaction vessel. Water reacted outside the system. After completion of the reaction, the salt produced by filtration was removed, and after further washing with water, epichlorohydrin was distilled off to obtain 279 g of an epoxy resin (epoxy resin C). The epoxy equivalent of the obtained resin was 190 g / eq. The peak temperature (melting point) in DSC measurement was 125 ° C., and the melt viscosity at 150 ° C. was 0.48 Pa · s.

Example 1
101 g of epoxy resin A obtained in Synthesis Example 1 as an epoxy resin component, triphenylmethane type polyvalent hydroxy resin (manufactured by Gunei Chemical Industry Co., Ltd., OH equivalent 97.5, softening point 105 ° C.) as a curing agent component 51 g was used. Further, curing catalyst A: 1.6 g of 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.) is used, and spherical silica (product name: FB-8S) as an inorganic filler. , Manufactured by Denki Kagaku Kogyo Co., Ltd.). Furthermore, 0.8 g of carnauba wax (product name: TOWAX171, manufactured by Toa Kasei Co., Ltd.) as a release agent, and 0.8 g of carbon black (product name: MA-100, manufactured by Mitsubishi Chemical Corporation) as a colorant were added. Were kneaded to obtain an epoxy resin composition. Using this epoxy resin composition, a molding temperature of 175 ° C. for 3 minutes. A cured product test piece was obtained under conditions of post-cure temperature 250 ° C. and 5 hours (molding condition A).

Example 2, Comparative Examples 1-4
An epoxy resin composition was prepared by kneading an epoxy resin, a curing agent, an inorganic filler, a curing catalyst, and other additives at a blending ratio shown in Table 1. And the hardened | cured material test piece was obtained by making the molding conditions into A or B. In addition, the numerical value in a table | surface shows the weight part in a mixing | blending.

The abbreviations in the table are explained as follows.
(Main agent)
Epoxy resin A: Epoxy resin obtained in Synthesis Example 1 Epoxy resin B; o-cresol novolac type epoxy resin (epoxy equivalent 200, softening point 65 ° C., manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
(Curing agent)
Curing agent A: triphenolmethane type polyvalent hydroxy resin (TPM-100 (manufactured by Gunei Chemical Industry Co., Ltd.), OH equivalent 97.5, softening point 105 ° C.)
Curing agent B: phenol novolac type polyvalent hydroxy resin (PSM-4261 (manufactured by Gunei Chemical Industry Co., Ltd.), OH equivalent 103, softening point 82 ° C.)
(Curing catalyst)
Curing catalyst A; 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.)
Curing catalyst B: Triphenylphosphine (Product name: TPP, manufactured by Hokuko Chemical Co., Ltd.)
(Inorganic filler)
Spherical silica (Product name: FB-8S, manufactured by Denki Kagaku Kogyo Co., Ltd.)
(Release agent)
Carnauba wax (Product name: TOWAX171, manufactured by Toa Kasei Co., Ltd.)
(Coloring agent)
Carbon black (Product name: MA-100, manufactured by Mitsubishi Chemical Corporation)

Moreover, it shape | molded on the molding conditions shown below using the epoxy resin composition which concerns on the said Examples 1-2 and Comparative Examples 1-4. And after obtaining the hardened | cured material test piece (epoxy resin hardened | cured material), it used for the various physical property measurement described below. The results are shown in Table 1.
Molding condition A; molding temperature 175 ° C., 3 minutes. Post cure temperature 250 ° C., 5 hours.
Molding condition B; molding temperature 175 ° C., 3 minutes. Post cure temperature 175 ° C., 5 hours.

1) Measurement of epoxy equivalent Using a potentiometric titrator, methyl ethyl ketone was used as a solvent, a brominated tetraethylammonium acetic acid solution was added, and the potential was measured using a 0.1 mol / L perchloric acid-acetic acid solution.

2) Melt viscosity It measured at 150 degreeC using the Toa Kogyo Co., Ltd. make and the CV-1S type | mold cone plate viscometer.

3) DSC exothermic peak temperature The exothermic peak temperature of the epoxy resin composition was determined under the condition of a temperature rising rate of 10 ° C / min using a DSC6200 thermomechanical measuring device manufactured by Seiko Instruments.

4) Spiral flow Molded with a spiral flow measurement mold in accordance with the standard (EMMI-1-66), the epoxy resin composition was molded under a spiral flow injection pressure (150 kgf / cm ² ) and a curing time of 3 minutes to flow. I investigated the length.

5) Glass transition point (Tg)
The Tg of the obtained cured product test piece was obtained under the condition of a temperature rising rate of 10 ° C./min using a Seiko Instruments TMA6100 type thermomechanical measuring device.

6) Bending strength The obtained cured product test piece was measured at 250 ° C. by a three-point bending test method according to JISK 6911.

7) Evaluation of long-term thermal decomposition stability (A) Weight retention rate Test piece weight after 1000 hours at 250 ° C. and test piece before heating using a constant temperature oven with a rotating frame (GPHH-201, manufactured by Tabai Espec Co., Ltd.) The weight retention (wt%) was determined from the difference from the weight. (B) Bending strength retention rate Using a thermostatic device with a rotating frame (GPHH-201, manufactured by Tabai Espec Co., Ltd.), the bending strength of the test piece after 1000 hours at 250 ° C. and the bending strength of the test piece before heating. The bending strength retention rate (%) was determined from the difference. The bending strength was measured at room temperature by the above test method.

Claims (6)

An epoxy resin composition containing an epoxy resin represented by the following general formula (1), a phenol-based curing agent, a curing catalyst, and an inorganic filler, wherein the epoxy resin composition is heated at a rate of 10 ° C./min. An epoxy resin composition having an exothermic peak top of 150 ° C. or higher when differential scanning calorimetry is performed under conditions.

(However, n represents an average value of 0.2 to 4.0, and G represents a glycidyl group.)   The epoxy resin composition according to claim 1, wherein the curing catalyst is at least one selected from the group consisting of imidazoles, organic phosphines, and amines. The epoxy resin composition according to claim 1 or 2, wherein the phenolic curing agent is represented by the following general formula (2) or (3).

(However, R shows a hydrogen atom or a C1-C6 hydrocarbon group, and l shows the number of 0 or 1.)

(However, A shows a benzene ring, a naphthalene ring, or a biphenyl ring, k shows the number of 1-15, m and p show the number of 1 or 2, respectively.) It contains an epoxy resin represented by the following general formula (1), a phenolic curing agent, a curing catalyst, and an inorganic filler, and has an exothermic peak top when differential scanning calorimetry is performed under a temperature rising rate of 10 ° C./min. A method for producing a cured epoxy resin product, comprising molding an epoxy resin composition having a temperature of 150 ° C or higher at a molding temperature of 100 ° C to 200 ° C, and further post-curing at 200 ° C to 300 ° C.

(However, n represents an average value of 0.2 to 4.0, and G represents a glycidyl group.)   The method for producing a cured epoxy resin product according to claim 4, wherein the glass transition temperature (Tg) is 200 ° C. or higher and the cured epoxy resin product for a power semiconductor encapsulant.   A semiconductor device, wherein a power semiconductor element is sealed with a cured epoxy resin for a power semiconductor sealing material obtained by the method according to claim 4.