TW201602151A - Epoxy resin composition, method for producing cured epoxy resin, and semiconductor device - Google Patents

Abstract

An epoxy resin composition which is capable of providing a cured product having excellent heat resistance, thermal decomposition stability and mechanical strength retainability, while exhibiting excellent fluidity during molding and being suitable for power device sealing materials; and a method for producing an epoxy resin cured product. An epoxy resin composition which contains an epoxy resin represented by general formula (1), a phenolic curing agent, a curing catalyst and an inorganic filler, and wherein the exothermic peak top thereof as determined by differential scanning calorimetry at a heating rate of 10 DEG C/minute is 150 DEG C or higher. A method for producing an epoxy resin cured product, wherein this epoxy resin composition is molded at 100-200 DEG C and then is subjected to postcuring at 200-300 DEG C. (In the formula, n represents an average of 0.2-4.0; and G represents a glycidyl group.)

Description

Epoxy resin composition, method for producing cured epoxy resin, and semiconductor device

The present invention relates to an epoxy resin composition, a method for producing an epoxy resin cured product, and a semiconductor device, and in particular, an epoxy resin cured product having excellent heat resistance and thermal decomposition stability, and at the same time of molding It is excellent in fluidity, and is particularly suitable as an epoxy resin composition for power semiconductors sealing, a method for producing an epoxy resin cured product, and a semiconductor device.

Epoxy resins are used in a wide range of industrial applications. As an example of this, there is a use as a sealing material in a semiconductor device. However, in recent years, performance has become more and more demanding in semiconductor devices, and the required power density is a field that is difficult to reach in conventional Si devices. Among them, a higher power density is expected, and a SiC power device developed as a device has been developed in recent years. However, in order to achieve high power density, the temperature of the wafer surface during operation also reaches 250 °C. Therefore, it is strongly desired to develop a sealing material that can withstand this temperature and maintain the physical properties for more than 1,000 hours.

Among them, Patent Documents 1 and 2 disclose the presence of biphenol- An epoxy resin, an epoxy resin composition, and a cured product of a biphenyl-phenyl aralkyl structure, and exhibits excellent heat resistance, moisture resistance, and thermal conductivity. However, even in the case where the epoxy resin represented by Patent Document 1 is used as described above, in the case of using a phenol novolak as a curing agent in a general molding method, only the glass transition temperature (Tg) before and after 200 ° C can be obtained. Hardened material. Therefore, there is a problem that it is not suitable for the characteristics of the sealing material of the SiC power device, which is capable of withstanding high heat resistance at a high operating temperature of 250 °C. Further, Patent Document 1 does not describe the long-term thermal stability required for a sealing material suitable for a SiC power device.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-60687

[Patent Document 2] Japanese Patent Laid-Open No. Hei 10-292032

Accordingly, an object of the present invention is to provide an epoxy resin cured product which is excellent in weight retention (thermal decomposition stability) and mechanical strength retention at a high temperature for a long period of time, and is formed at the same time. The fluidity at the time is also superior, and it is suitable as an epoxy resin composition for a power device sealing material. Further, another object of the present invention is to provide a power pack suitable for use by using the epoxy resin composition. A method of sealing a sealant-like epoxy resin.

That is, the present invention is an epoxy resin composition containing an epoxy resin, a phenolic curing agent, a curing catalyst, and an inorganic filler represented by the following general formula (1), which is characterized in that the epoxy resin When the composition is subjected to differential scanning calorimetry at a temperature rising rate of 10 ° C /min, the peak of the exothermic peak is 150 ° C or higher. (However, n is 0.2 to 4.0 in terms of the average value, and G is a glycidyl group in the G system).

Further, in the epoxy resin composition according to the invention, the curing catalyst is at least one selected from the group consisting of imidazoles, organophosphines, and amines.

Further, the present invention is the epoxy resin composition described above, wherein the phenolic curing agent is represented by the following general formula (2) or (3). (However, R represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and 1 represents a number of 0 or 1).

(However, A represents a benzene ring, a naphthalene ring, or a biphenyl ring, k represents a number from 1 to 15, and m and p represents a number of 1 or 2, respectively).

Moreover, the present invention provides a method for producing an epoxy resin cured product, which comprises an epoxy resin, a phenolic curing agent, a curing catalyst, and an inorganic filler represented by the following general formula (1), and is heated. An epoxy resin composition having a heat peak height of 150 ° C or higher at a speed of 10 ° C / min under the condition of a differential scanning calorimeter is formed at a molding temperature of 100 ° C to 200 ° C and further at 200 ° C to 300 ° C. After hardening, (However, n is 0.2 to 4.0 in terms of the average value, and G is a glycidyl group in the G system).

The cured epoxy resin obtained above is suitable for use in power semiconductor sealing materials. Further, the present invention is a semiconductor device characterized by sealing a power semiconductor element with the cured epoxy resin.

The cured epoxy resin obtained by using the epoxy resin composition of the present invention is excellent in high Tg, weight retention at high temperature for a long period of time, and mechanical strength retention, and the epoxy resin composition is formed in the form of Superior liquidity at the time. Therefore, the epoxy resin composition of the present invention can be suitably used for the sealing material of power semiconductors.

[Best Practice for Carrying Out the Invention]

Hereinafter, the present invention will be described in detail.

The epoxy resin represented by the above general formula (1) which is an essential component of the epoxy resin composition of the present invention can be produced by reacting a polyhydric hydroxy resin represented by the following general formula (a) with epichlorohydrin. . Further, the polyhydric hydroxy resin can be produced by reacting a biphenol with a phenyl condensing agent represented by the following general formula (b).

(However, n is 0.2 to 4.0 in terms of the average value).

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

Examples of the biphenols which are synthetic raw materials of the polyvalent hydroxy resin include dihydroxyphenyl groups such as 4,4'-dihydroxyphenyl and 2,2'-dihydroxyphenyl. These difunctional phenolic compounds are substituted by 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 t-butyl group, a pentyl group, a cyclohexyl group, and a phenyl group. Further, these dihydroxyphenyl groups may be used singly or in combination of two or more kinds.

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 an o-form, an m-form, and a p-form, but is preferably an m-form or a p-form. Specifically, for example, p-xylylene glycol, α,α'-dimethoxy-p-xylene, α,α'-diethoxy-p-xylene, α , α'-diisopropyl-p-xylene, α,α'-dibutoxy-p-xylene, m-decanediol, α,α'-dimethoxy-m-xylene, ,,α'-diethoxy-m-xylene, α,α'-diisopropoxy-m-xylene, α,α'-dibutoxy-m-xylene, and the like.

The molar ratio of the phenyl-based condensing agent to the phenyl-based condensing agent must be 1 mol or less, usually 0.1 to 0.7 mol, relative to, for example, 4,4'-dihydroxyphenyl 1 mol. It is preferably in the range of 0.2 to 0.5 mol. When it is less than the above, the crystallinity becomes strong and the solubility of epichlorohydrin at the time of synthesizing the epoxy resin is lowered, and the melting point of the obtained epoxy resin becomes high and the workability is lowered. . Moreover, when it is more than the above, the crystallinity of the resin is lowered, and the softening point and the melt viscosity are increased, which hinders handling workability and formability.

Further, when p-nonanediol is used, the condensing agent may be reacted without a catalyst, but generally, the condensation reaction is carried out in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from known mineral acids and organic acids, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and citric acid, or formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, and methanesulfonic acid. An organic acid such as trifluoromethanesulfonic acid or a Lewis acid such as zinc chloride, aluminum chloride, iron chloride or boron trifluoride, or a solid acid.

The reaction is carried out at 10 to 250 ° C for 1 to 20 hours. Further, in the reaction, an alcohol such as methanol, ethanol, propanol, butanol, ethylene glycol, acesulfame or acesulfame, or an aromatic such as benzene, toluene, chlorobenzene or dichlorobenzene may be used. A compound or the like is used as a solvent. After the completion of the reaction, water or alcohol generated by the solvent or the condensation reaction is removed as needed.

The method for producing an epoxy resin of the present invention which is reacted with a polyhydric hydroxy resin represented by the general formula (a) and epichlorohydrin will be described. This reaction can be carried out in the same manner as the well-known epoxidation reaction.

For example, after dissolving the polyhydric hydroxy resin represented by the general formula (a) in an excess amount of epichlorohydrin, it is in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at 50 to 150. A method of reacting for 1 to 10 hours in a range of ° C, preferably 60 to 120 ° C. The amount of epichlorohydrin used in this case is from 0.8 to 2 moles, preferably from 0.9 to 1.2 moles, relative to the hydroxyl group of the polyhydric hydroxy resin. After the completion of the distillation, excess epichlorohydrin is dissolved, and the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, and the mixture is filtered and washed with water to remove the inorganic salt. Then, the above-mentioned general formula is obtained by distilling off the solvent. (1) Epoxy resin indicating the target. When the epoxidation reaction is carried out, a catalyst such as a quaternary ammonium salt may also be used.

The purity of the epoxy resin of the present invention, particularly the amount of hydrolyzable chlorine, is preferably in view of the improvement of the reliability of the applied electronic component. Although it is not particularly limited, it is preferably 1000 ppm or less, more preferably 500 ppm or less. Further, the term "hydrolyzable chlorine" as used in the present invention means a value measured by the following method. That is, 0.5 g of the sample was dissolved in 30 ml of dioxane, 10 ml of 1N-KOH was added, and the mixture was boiled and refluxed for 30 minutes, and then cooled to room temperature, and then 100 ml of 80% acetone water was added thereto, and potentiometric titration was performed with an aqueous solution of 0.002 N-AgNO _{3 .} And get the value.

Next, the epoxy resin composition of the present invention will be described. The epoxy resin composition of the present invention contains the epoxy resin, the phenolic curing agent, the curing catalyst, and the inorganic filler of the above general formula (1).

As a curing catalyst blended in the epoxy resin composition, in order to promote hardening while improving fluidity during molding, A hardening catalyst (high temperature active catalyst) having an active point in a high temperature region is preferably used in the epoxy resin composition.

The content of the curing catalyst is preferably in the range of 0.2 to 5 parts by weight based on 100 parts by weight of the epoxy resin. It is preferably 0.5 to 3 parts by weight, and more preferably 0.5 to 2.5 parts by weight. If it is less than the above, the hardenability will be lowered, and conversely, if it is larger than the above, the effect of improving the fluidity at the time of molding will not be sufficiently exhibited.

The DSC exothermic peak temperature of the epoxy resin composition using a high-temperature active catalyst is 150 ° C or higher, preferably 155 ° C or higher, and more preferably 165 ° C or higher. When the exothermic temperature is lower than 150 ° C, a hardening reaction occurs at the time of molding, and the effect of improving the fluidity cannot be sufficiently exhibited. The DSC exothermic peak temperature indicates the maximum heat generation when the epoxy resin composition containing the high-temperature active catalyst as a curing catalyst is subjected to differential scanning calorimetry (DSC measurement) under the conditions of a temperature increase rate of 10 ° C /min. The temperature of the peak (heat peak high point). Further, in consideration of the upper limit of the DSC exothermic peak temperature, it is considered that the range of the curing temperature due to post-hardening is preferably 200 ° C to 300 ° C, and is substantially 300 ° C.

As the curing catalyst (high-temperature active catalyst), examples thereof include imidazoles, organic phosphines, and amines. As the imidazoles, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-heptadecylimidazole, 2,4 can be exemplified. -diamino-6-[2'-dimethylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4' -methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazole-(1')]-ethyl-s - triazine, etc.; as an organic phosphine, For example, ginseng-(2,6-dimethoxyphenyl)phosphine, tri-p-tolylphosphine, ginseng (p-chlorophenyl)phosphine, ginseng (p-methoxyphenyl)phosphine, etc. As the amines, a phenol phenolic salt of 1,8-dibicyclobicyclo(5,4,0)undecene-7 and the like can be exemplified. One or two or more of these may be used in combination.

In the present invention, it has been found that by using a high-temperature active catalyst having a specific active temperature region as a hardening catalyst, it is possible to suppress a decrease in fluidity, and further, in terms of hardening conditions, particularly in the case of using the epoxy resin of the present invention. The hardening conditions at special high temperatures will have a large effect on the glass transition temperature.

Further, a phenolic curing agent is used as a curing agent. In the field of high electrical insulation required for semiconductor sealing materials and the like, it is preferred to use a polyhydric phenol as a curing agent. Specific examples of the curing agent will be described below.

Examples of the polyhydric phenols include divalent phenols, bisphenol F, bisphenol S, bismuth bisphenol, hydroquinone, resorcinol, catechol, biphenols, and naphthalenediols. Phenols; further ginseng-(4-hydroxyphenyl)methane, 1,1,2,2-indole (4-hydroxyphenyl)ethane, phenolic novolac, o-cresol novolac, naphthol novolac, dicyclopentan A trivalent or higher phenol or the like represented by a diene type phenol resin or a phenol aralkyl resin. Further, there are phenols, naphthols or bisphenol A, bisphenol F, bisphenol S, bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, m-benzene. Divalent phenols such as diphenol, catechol, naphthalenediol, and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-nonanediol, p-nonanediol dimethyl ether, a polyphenolic compound synthesized by reacting a crosslinking agent such as divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyl, divinylbiphenyl or diisopropenylbiphenyl; Class and double (chlorine A biphenyl aralkyl type phenol resin obtained by methylation of biphenyl or the like. Further, examples thereof include naphthol aralkyl resins synthesized from naphthols and p-xylylene dichlorides.

Among them, a preferred phenolic curing agent is preferably an aralkyl type phenol resin represented by the following general formula (2) or (3).

Here, R represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and 1 represents a number of 0 to 2.

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

By using the hardener represented by the general formula (2), it is found that the high Tg of 250 ° C or higher required for the power device sealant is obtained by It maintains its glass state during long-term heat resistance test and exhibits high thermal decomposition stability. Further, by using the curing agent represented by the general formula (3), in particular, a biphenyl structure excellent in thermal stability is introduced, in particular, excellent weight retention and bending strength retention ratio are exhibited.

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

Here, as the compound containing a phenolic hydroxyl group, exemplified by phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 4-ethylphenol, 2-propanol, 4-propanol 4-tert-butanol, 4-pentanol, 4-tert-pentanol, 4-pivalol, 2-cyclopentol, 2-hexol, 4-hexol, 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 compound containing a phenolic hydroxyl group, phenol, hydroquinone, resorcin, catechol, benzenetriol, phloroglucinol, 1-naphthol, 2-naphthol, 1, 5-naphthalenediol, 1,6-naphthalenediol, 1,7-naphthalenediol, 2,6-naphthalenediol, 2,7-naphthalenediol, 2,2'-dihydroxyphenyl, 3, 3'-dihydroxyphenyl, 4,4'-dihydroxyphenyl and the like.

As the aromatic crosslinking agent, those having a benzene skeleton and having a biphenyl skeleton are used. The benzene skeleton may be any of an o-body, an m-body, and a p-form, but is preferably an m-body or a p-body. Specifically, for example, p-nonanediol, α,α'-dimethoxy-p-xylene, α,α'-diethoxy-p-xylene, α,α'-diiso Propyl-p-xylene, α,α'-dibutoxy-p-xylene, M-decanediol, α,α'-dimethoxy-m-xylene, α,α'-diethoxy-m-xylene, α,α'-diisopropoxy-m-di Toluene, α,α'-dibutoxy-m-xylene, and the like. Further, as the biphenyl skeleton, 4,4'-dihydroxymethylbiphenyl, 2,4'-dihydroxymethylbiphenyl, 2,2'-dihydroxymethylbiphenyl, 4, 4'-dimethoxymethylbiphenyl, 2,4'-dimethoxymethylbiphenyl, 2,2'-dimethoxymethylbiphenyl, 4,4'-diisopropoxy Methylbiphenyl, 2,4'-diisopropoxymethylbiphenyl, 2,2'-diisopropoxymethylbiphenyl, 4,4'-dibutoxymethylbiphenyl, 2 , 4'-dibutoxymethylbiphenyl, 2,2'-dibutoxymethylbiphenyl, and the like. The position of substitution of biphenyl relative to a functional group such as a hydroxymethyl group may be any of the 4, 4'-position, the 2, 4'-position, and the 2, 2'-position, but is desirable as a condensing agent. The compound is a 4,4'-body, and among the total cross-linking agent, it is particularly preferable that the 4,4'-form is 50% by weight or more. If it is less than the above, the curing rate of the epoxy resin hardener may be lowered, or the obtained cured product may be easily brittle.

In the above general formula (3), k is a number from 1 to 15. The value of k can be easily prepared by changing the molar ratio of the phenolic hydroxyl group-containing compound to the above-mentioned crosslinking agent. That is, the more the compound containing a phenolic hydroxyl group is used in excess with respect to the crosslinking agent, the smaller the value of k can be controlled. The larger the value of k, the higher the softening point and viscosity of the resulting resin. Further, the smaller the value of k, the lower the viscosity, but the amount of unreacted phenolic hydroxyl group-containing compound during synthesis increases, so that the production efficiency of the resin is lowered. The molar ratio of the two is actually in the range of 1 mol or less, preferably 0.1 to 0.9 mol, relative to the compound 1 containing the phenolic hydroxyl group. If it is less than 0.1 mol, the amount of unreacted phenolic hydroxyl group-containing compound will increase, which is industrially unsatisfactory.

The blending amount of the phenolic curing agent in the epoxy resin composition is determined by balancing the epoxy group in the epoxy resin represented by the general formula (1) with the equivalent of the hydroxyl group of the phenolic curing agent. The equivalent ratio of the epoxy resin and the hardener is usually in the range of 0.2 to 5.0, preferably 0.5 to 2.0, in combination with the phenolic curing agent of the above general formula (2) or (3). Good is in the range of 0.8~1.5. When it is larger or smaller than this, the hardenability of the epoxy resin composition is lowered, and the heat resistance, mechanical strength, and the like of the cured product are also lowered.

Further, in the epoxy resin composition, in addition to the phenolic curing agent, other curing agents may be blended as the curing agent component. The curing agent in this case may be, for example, dicyandiamide, an acid anhydride, an aromatic or an aliphatic amine, and may be used by mixing one or two or more of these curing agents. However, the amount of the curing agent other than the phenolic curing agent of the above general formula (2) or (3) is preferably 50% by weight or less of the total curing agent.

The amount of the epoxy resin represented by the general formula (1) in the epoxy resin composition is preferably from 0.1% by weight to 28% by weight, preferably from 3% by weight to 16% by weight. When the compounding amount of the epoxy resin of the general formula (1) is less than 0.1% by weight, the heat resistance and thermal decomposition stability of the cured product cannot be sufficiently improved, and if it is more than 28% by weight, the equivalent of the epoxy group and the hydroxyl group The balance will be deteriorated, so the heat resistance and mechanical strength of the cured product are lowered.

Further, in the epoxy resin composition, in addition to the epoxy resin represented by the general formula (1), other epoxy resins may be blended as the epoxy resin component. As the epoxy resin at this time, a general epoxy resin having two or more epoxy groups in the molecule can be used. If an example There are: bisphenol A, bisphenol F, bisphenol S, bismuth bisphenol, 4,4'-biphenol, 3,3',5,5'-tetramethyl-4,4'-dihydroxyphenyl, Divalent phenolic epoxides such as resorcinol and naphthalenediol, ginseng-(4-hydroxyphenyl)methane, 1,1,2,2-indole (4-hydroxyphenyl)ethane a phenolic epoxide such as phenol novolac or o-cresol phenolic or the like, an epoxide of a co-condensed resin obtained from dicyclopentadiene and a phenol, and a cresol and formaldehyde and an alkoxylate. An epoxide of a co-condensation resin obtained by substituting a naphthalene, an epoxide of a phenol aralkyl resin obtained from a phenol and a p-xylylene dichloride, or the like, and a phenol and a bis(chloromethyl group) An epoxide of a biphenyl aralkyl type phenol resin obtained by biphenyl or the like, an epoxide of a naphthol aralkyl resin synthesized from a naphthol and a p-xylylene dichloride, or the like. These epoxy resins may be used alone or in combination of two or more. However, the amount of the epoxy resin represented by the general formula (1) is preferably from 5 to 100% by weight, preferably from 60 to 100% by weight, based on the total amount of the epoxy resin.

Examples of the inorganic filler include spherical or crushed vermiculite, vermiculite powder such as crystalline vermiculite, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, and hydrated alumina. , boron nitride, aluminum nitride, tantalum nitride, tantalum carbide, titanium nitride, zinc oxide, tungsten carbide, magnesium oxide, and the like. The compounding amount of the inorganic filler in the epoxy resin composition is preferably 70% by weight to 95% by weight, more preferably 80% by weight to 90% by weight, based on the semiconductor sealing material.

For the epoxy resin composition of the present invention, a release agent such as carnauba wax or OP paraffin, a 4-aminopropyl ethoxy decane, or a γ-glycidoxypropyl trimethyl group may be further prepared as needed. Oxydecane A coloring agent such as a mixture or carbon black, a flame retardant such as antimony trioxide, or a lubricant such as calcium stearate.

Further, in the epoxy resin composition of the present invention, polyester, polyamine, polyimine, polyether, polyurethane, petroleum resin, oxime resin, oxime coumarinone may be appropriately formulated. An oligomer or a polymer compound such as a resin or a phenoxy resin is used as a modifier or the like. In this case, the amount is usually in the range of 2 to 30 parts by weight based on 100 parts by weight of the epoxy resin.

Further, the epoxy resin composition of the present invention may be formulated with additives such as a pigment, a flame retardant, a thixotropic imparting agent, a coupling agent, a fluidity enhancer, and an antioxidant.

Among them, examples of the pigment include organic or inorganic filler pigments and flaky pigments. Examples of the thixotropic imparting agent include an anthraquinone-based, a castor oil-based, an aliphatic guanamine wax, an oxidized polyethylene wax, and an organic bentonite.

The epoxy resin composition of the present invention is immersed in a varnish state in which an organic solvent is dissolved, and then impregnated into a fibrous material such as a polyester cloth such as a glass cloth, an aromatic polyamine nonwoven fabric or a liquid crystal copolymer, and then subjected to a solvent. It can be removed to make a prepreg. Further, a laminate may be formed by coating on a sheet of a copper foil, a stainless steel foil, a polyimide film, a polyester film or the like as the case may be.

The method for preparing the epoxy resin composition of the present invention can be exemplified by any method capable of uniformly dispersing and mixing various raw materials, but as a usual method, a specific blending amount of raw materials is sufficiently mixed by a mixer or the like. Thereafter, the mixture is melt-kneaded by a mixing roll, an extruder, or the like, and cooled and pulverized.

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

The cured product of the present invention is obtained by thermally curing the above epoxy resin composition. In the epoxy resin composition of the present invention, for the purpose of obtaining a cured product, for example, transfer molding, press molding, injection molding, injection molding, extrusion molding, or the like can be applied, but from the viewpoint of mass productivity, Transfer forming is preferred.

The method for curing the epoxy resin composition of the present invention is formed by using 100 ° C to 200 ° C, preferably 120 ° C to 190 ° C, and preferably 150 to 180 ° C, and 200 ° C to 300 ° C. It is preferably 220 ° C to 280 ° C, and is preferably post-cured at 230 to 270 ° C to produce a cured product which is excellent in Tg, weight retention at high temperature for a long period of time, and mechanical strength retention. The Tg of the cured product is preferably 200 ° C or higher, and more preferably 250 ° C or higher. Since the power semiconductor operates at a temperature exceeding 200 ° C, when the Tg is a sealing material of less than 200 ° C, it is not sufficiently sealed and is not durable.

The molding time is preferably from 1 to 60 minutes, and further preferably from 1 minute to 10 minutes. When the forming time is long, the productivity is deteriorated, and if it is too short, demolding is difficult. The post-hardening time is preferably from 10 minutes to 10 hours, preferably from 30 minutes to 8 hours, particularly from 2 hours to 6 hours. When the post-hardening time is short, the hardening cannot be sufficiently performed, and thus it is not possible to obtain sufficient characteristics such as heat resistance and mechanical properties. Moreover, if it exceeds 10 hours, productivity will fall.

The epoxy resin composition of the present invention can be subjected to a hardening reaction even in a high-temperature post-hardening temperature region in which a general epoxy resin composition is unreactable, and can obtain a very high Tg and have a high temperature for a long period of time. A cured product such as weight retention, mechanical strength retention, and the like.

[Examples]

Hereinafter, the present invention will be specifically described based on Synthesis Examples, Examples, and Comparative Examples.

Synthesis Example 1

In a 2 L four-necked flask, 186 g (1.0 mol) of 4,4'-dihydroxyphenyl group, 69 g (0.5 mol) of p-nonanediol, and 743 g of diethylene glycol dimethyl ether were charged as an acid touch. The medium was poured into 2.55 g of p-toluenesulfonic acid and heated to 160 °C. Then, the mixture was reacted for 3 hours while stirring at 160 °C. Next, a part of diethylene glycol dimethyl ether was distilled off under reduced pressure, and then 740 g of epichlorohydrin was charged and dissolved. Next, 155.0 g of a 48% aqueous sodium hydroxide solution was added dropwise thereto at a temperature of 75 ° C for 4 hours under reduced pressure, and the water distilled off from the dropwise addition was separated from the epichlorohydrin in a separation tank, and the epichlorohydrin was returned. The reaction was carried out by going to the reaction vessel and removing water to the outside of the system. After completion of the reaction, the salt formed was removed by filtration, and after washing with water, the 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) measured by DSC was 125 ° C, and the melt viscosity at 150 ° C was 0.48 Pa s.

Example 1

Using epoxy resin A obtained in Synthesis Example 1 as an epoxy resin component, and a triphenylmethane-type polyhydric hydroxy resin (manufactured by Qunrong Chemical Industry Co., Ltd., OH equivalent: 97.5, softening point: 105 ° C), 51 g as a hardener component. . Further, 1.6 g of a curing catalyst A: 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Chemicals Co., Ltd.) was used, and globular vermiculite was used (product name: 747 g, manufactured by FB-8S, Electric Chemical Industry Co., Ltd., as an inorganic filler. Further, 0.8 g of carnauba wax (product name: TOWAX 171, manufactured by Toago Chemical Co., Ltd.) was added as a release agent, and 0.8 g of carbon black (product name: MA-100, manufactured by Mitsubishi Chemical Corporation) was added as a coloring agent, and kneading was carried out. After that, an epoxy resin composition can be obtained. The epoxy resin composition was used to carry out a molding temperature of 175 ° C for 3 minutes. A cured test piece was obtained under the conditions of a post-hardening temperature of 250 ° C for 5 hours (forming condition A).

Example 2, Comparative Example 1~4

The epoxy resin composition was prepared by kneading an epoxy resin, a hardener, an inorganic filler, a curing catalyst, and other additives in the blending ratio shown in Table 1. Further, a cured test piece was obtained by forming the molding conditions with A or B. Further, the numerical values in the table indicate the parts by weight.

The abbreviations in the table are 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 & Sumitomo Chemical Co., Ltd.)

(hardener)

Hardener A: Trisphenol methane type polyhydroxy resin (TPM-100 (manufactured by Qunrong Chemical Industry Co., Ltd.), OH equivalent 97.5, softening point 105 ° C)

Hardener B: phenol novolac type polyhydric hydroxy resin (PSM-4261 (manufactured by Qunrong Chemical Industry Co., Ltd.), OH equivalent 103, softening point 82 ° C)

(hardening catalyst)

Hardening catalyst A: 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.)

Hardening Catalyst B: Triphenylphosphine (product name: TPP, manufactured by Beixing Chemical Industry Co., Ltd.)

(inorganic filler)

Spherical vermiculite (product name; FB-8S, made by Electric Chemical Industry Co., Ltd.)

(release agent)

Carnauba wax (product name: TOWAX171, manufactured by East Asia Chemical Co., Ltd.)

(Colorant)

Carbon black (product name: MA-100, manufactured by Mitsubishi Chemical Corporation)

Further, using the above Examples 1 to 2 and Comparative Examples 1 to 4 The epoxy resin composition was molded under the molding conditions shown below. Further, after obtaining a cured test piece (hardened epoxy resin), various physical properties described below were provided. The results are shown in Table 1.

Molding condition A: molding temperature: 175 ° C, 3 minutes, post-hardening temperature 250 ° C, 5 hours.

Molding condition B: molding temperature: 175 ° C, 3 minutes, post-hardening temperature 175 ° C, 5 hours.

1) Determination of epoxy equivalent

Using a potentiometric titration apparatus and using methyl ethyl ketone as a solvent, a tetraethylammonium bromide acetic acid solution was added, and the measurement was performed by a potentiometric titration apparatus using a 0.1 mol/L perchloric acid-citric acid solution.

2) Melt viscosity

The measurement was carried out at 150 ° C using a CV-1S cone-plate viscometer manufactured by Toagos Corporation.

3) DSC heating peak temperature

The exothermic peak temperature of the epoxy resin composition was determined by a DSC 6200 type thermomechanical measuring apparatus manufactured by Seiko Instruments under the conditions of a temperature increase rate of 10 ° C /min.

4) Spiral flow

The epoxy resin composition was molded under the conditions of a spiral flow injection pressure (150 Kgf/cm ² ) and a curing time of 3 minutes using a mold for spiral flow measurement according to the specification (EMMI-1-66), and the flow length was examined.

5) Glass transfer point (Tg)

The Tg of the obtained cured test piece was determined by a thermostat measuring device of a TMA6100 type manufactured by Seiko Instruments under the conditions of a temperature increase rate of 10 ° C /min.

6) Flexural strength

The obtained cured test piece was measured at 250 ° C according to JIS K 6911 by a 3-point bending test method.

7) Long-term thermal decomposition stability evaluation (A) Weight retention rate

Using a thermostat equipped with a rotating frame (GPHH-201, manufactured by Tabai Espec Co., Ltd.), the weight retention ratio (wt%) was determined from the difference between the weight of the test piece after 1000 hours at 250 ° C and the weight of the test piece before heating. ).

(B) bending strength retention rate

Using a thermostat equipped with a rotating frame (GPHH-201, manufactured by Tabai Espec Co., Ltd.), the bending strength was determined from the difference between the bending strength of the test piece after 1000 hours at 250 ° C and the bending strength of the test piece before heating. Retention rate (%). The measurement of the bending strength was carried out at room temperature by the above test method.

Claims (6)

An epoxy resin composition comprising an epoxy resin represented by the following general formula (1), a phenolic curing agent, a curing catalyst, and an inorganic filler, characterized in that the epoxy resin composition is at a temperature rising rate When the differential scanning calorimetry is performed under the condition of 10 ° C / min, the peak of the exothermic peak is 150 ° C or higher. (However, n is 0.2 to 4.0 in terms of the average value, and G is a glycidyl group in the G system). The epoxy resin composition according to claim 1, wherein the curing catalyst is at least one selected from the group consisting of imidazoles, organophosphines, and amines. The epoxy resin composition according to claim 1 or 2, wherein the phenolic hardener is represented by the following general formula (2) or (3), (However, R represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and 1 is a number of 0 or 1), (However, A represents a benzene ring, a naphthalene ring, or a biphenyl ring, k represents a number from 1 to 15, and m and p represents a number of 1 or 2, respectively). A method for producing an epoxy resin cured product, which comprises an epoxy resin, a phenol-based curing agent, a curing catalyst, and an inorganic filler represented by the following general formula (1), and is heated at a rate of 10 ° C/min. Under the conditions of the differential scanning calorimetry, the epoxy resin composition having a peak of 150 ° C or higher is formed at a molding temperature of 100 ° C to 200 ° C, and then post-cured at 200 ° C to 300 ° C. (However, n is 0.2 to 4.0 in terms of the average value, and G is a glycidyl group in the G system). The method for producing an epoxy resin cured product according to claim 4, wherein the glass transition temperature (Tg) is 200 ° C or higher and is an epoxy resin cured product for a power semiconductor sealing material. A semiconductor device characterized in that a power semiconductor element is sealed with an epoxy resin hardened material of a power semiconductor sealing material obtained by the method of claim 4 or 5.