JPS6325009B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an epoxy resin composition for semiconductor encapsulation with excellent moisture resistance and reliability, which is characterized in that it contains an inorganic filler directly treated with two or more types of surface treatment agents. It is. [Prior Art] Currently, resin encapsulation methods are widely used in which semiconductor elements such as ICs, LSIs, and VLSIs are encapsulated using silicone resin or epoxy resin. Among these, epoxy resins are widely used as semiconductor encapsulating resins because they provide relatively excellent airtightness and are inexpensive. However, resin sealing has inferior moisture resistance and reliability compared to hermetic sealing, and causes corrosion of the aluminum wiring and pads of semiconductor elements. The cause of the above corrosion is thought to be that ionic impurities and hydrolyzable chlorine contained in the sealing material are liberated by water that has penetrated into the resin and corrode the metal. These water and impurities liberated by water are
It is thought that corrosion mainly occurs by penetrating into the interior through the resin/inorganic filler interface and reaching the semiconductor element. Therefore, in order to improve the moisture resistance reliability of resin sealing, it is important to control the amount of ionic impurities and hydrolyzable chlorine to a minimum, and to suppress the hygroscopicity of the resin composition. Conventionally, interface treatment of inorganic fillers has been carried out primarily for the purpose of improving electrical insulation and mechanical strength. As a surface treatment agent, there is a direct treatment method in which an inorganic filler is directly treated with a silane coupling agent that has a functional group (epoxy group, amino group, etc.) that can chemically bond with an organic matrix, or a silane coupling agent is used during polymer compounding. Surface treatment has been carried out by adding an integral blend method or a combination of both. [Problem to be solved by the invention] Although the surface of the inorganic filler treated in this way is more hydrophobic than the untreated surface, the hydrophobicity of the surface is weaker because the coupling agent has a polar functional group. However, it had the disadvantage of poor moisture resistance and reliability. The present invention has been made to solve the above-mentioned problems, and has excellent moisture resistance and reliability by imparting strong hydrophobicity to the surface of the inorganic filler as well as providing a functional group that can chemically bond with the organic matrix. Moreover, it is an object of the present invention to obtain an epoxy resin composition for semiconductor encapsulation that has excellent mechanical properties and electrical insulation properties. [Means for Solving the Problems] That is, the present invention provides an epoxy resin for semiconductor encapsulation which essentially contains an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler treated with a silane coupling agent. An epoxy resin for semiconductor encapsulation, characterized in that the composition uses the inorganic filler treated with one or more hydrophobic silane compounds (a) and one or more silane coupling agents (b). present in the composition. The upper orbital hydrophobic silane compound (a) is represented by the general formula () RnSi(OR′) _4-o (), and the silane coupling agent (b) is represented by the general formula () YnSi(OR′) _4-o ( ). In both formulas, R represents an alkyl group or a phenyl group, and R' is a hydrogen atom or a group having 1 to 1 carbon atoms.
It represents five alkyl groups, Y is a monovalent organic group having an epoxy group or an amino group, and n is an integer of 1 to 3. In the present invention, by directly treating the surface of an inorganic filler with a silane compound (a), a highly hydrophobic and uniform surface can be obtained, and by treating with a silane coupling agent (b), an organic matrix can be obtained. It is possible to obtain an inorganic filler that chemically bonds with the epoxy resin composition and provides an epoxy resin composition for semiconductor encapsulation with excellent mechanical and electrical properties. In particular, when a silane compound (a) containing a phenyl group in R is used, the hydrophobic effect is high. Various types of epoxy resins can be used as the epoxy resin used in the present invention, such as novolak epoxy resin, bisphenol A epoxy resin, and alicyclic epoxy resin. Preference is given to using epoxy resins. These epoxy resins can be used alone or in combination of two or more. In addition to these epoxy resins, epoxy resins such as brominated novolac epoxy resins and brominated bisphenol A-based epoxy resins can also be used in combination, if necessary. Examples of the curing agent used in the present invention include phenolic compounds such as phenol novolak, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyleneendomethylene phthalic anhydride, chlorendic anhydride, hydromeritic anhydride, and phenolic anhydride. Examples include acid anhydride compounds such as decenylsaxenic acid. Examples of the curing accelerator used in the present invention include 2-ethylimidazole, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, and 1-ethylimidazole.
Imidazole compounds such as benzyl-2-methylimidazole, 2-heptadecylimidazole, 1-vinyl-2-methylimidazole, and 2-undecylimidazole, and their precursor imidazoline compounds, such as triethylamine, 2,4,6 -dimethylmethylaminophenol, benzyldimethylamine, α-methylbenzylmethylamine, piperidine, dimethyllaurylamine, dialkylaminomethanolamine,
Tetramethylguanidine, 2-dimethylamino-
2-hydroxypropane, N,N'-dimethylpiperazine, N-methylmorpholine, piperazine,
Tertiary compounds such as 2-(dimethylaminomethyl)phenol, hexamethylenetetramine, 1-hydroxylethyl-2-heptadecylglyoxalidine, etc.
amines, other amine compounds, and imidazole compounds. As the inorganic filler used in the present invention, crystalline silica, fused silica, alumina, etc. are used in an amount of 100 to 600 parts by weight based on 100 parts by weight of the resin content. General formula () of the surface treating agent that is a feature of the present invention
As the silane compound (a) represented by, for example,
Methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyldimethylethoxysilane , phenyltripentoxysilane, triphenylsilanol, etc., and particularly preferred are silane compounds having a phenyl group such as phenyltrimethoxysilane and phenyltriethoxysilane. Examples of the silane coupling agent (b) represented by the general formula () include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltripentoxysilane, β-(3,4-
Examples include epoxycyclohexyl)ethyltrimethoxysilane and γ-aminopropyltriethoxysilane. The above-mentioned surface treatment agent is prepared by directly treating an inorganic filler with one or more silane compounds (a) and one or more silane coupling agents (b) using a Henschel mixer, etc., and adding it to an organic matrix as necessary. It can also be added to. Furthermore, when directly treating the inorganic filler, the surface treatment agent can be dissolved in water, a solvent such as ethyl alcohol, isopropyl alcohol, or a mixed solvent thereof. This direct treatment uses silane compounds (a) for inorganic fillers.
and the silane coupling agent (b) may be treated simultaneously or in any order. Here, the blending amount of the silane compound (a) as a surface treating agent and the silane coupling agent (b) is 3% by weight or less, preferably 0.1 to 2% by weight, based on the inorganic filler. The weight ratio of the silane compound (a) and the silane coupling agent (b) is within the range of silane compound (a)/silane coupling agent (b) = 0.1 to 10. The amount of the above surface treatment agent added to the inorganic filler is
If it is less than 0.1% by weight, the effect of hydrophobization is small and the chemical bonding at the organic matrix/inorganic filler interface is insufficient, resulting in little effect of improving mechanical and electrical properties. If 3% by weight or more is blended, the excess surface treating agent will be liberated by absorbed water, which will accelerate the corrosion of metals. Furthermore, if the weight ratio of the silane compound (a) to the silane coupling agent (b) is less than 0.1, the effect of making the surface of the inorganic filler hydrophobic is small. When the weight ratio is more than 10, chemical bonding at the organic matrix/inorganic filler interface becomes difficult to occur, the effect of improving mechanical properties and electrical properties is small, and the hydrophobization effect is also reduced due to unreacted functional groups. A coloring agent such as carbon black, a mold release agent such as carnauba wax or polyethylene wax, and a flame retardant such as antimony trioxide may be added to the composition of the present invention, if necessary. The composition of the present invention can be applied to a powder mixing device such as a Henschel mixer or a Nauter mixer for interfacial treatment of an inorganic filler, and a known mixing device used for preparing epoxy resins and silicone resins. For example, it can be easily prepared using a roll, kneader, light machine, etc. [Example] The present invention will be explained below with reference to Examples and Comparative Examples. An inorganic filler whose surface was treated with a silane compound and a silane coupling agent having the composition shown in Tables 1 and 2 was mixed at 1000 rpm using a Henschel mixer.
The mixture was prepared by stirring and mixing for 10 minutes. Examples 1 to 9,
In Comparative Examples 1 to 9, the epoxy resin, curing agent, curing accelerator, inorganic filler prepared as above, surface treatment agent, coloring agent, and mold release agent were used in the proportions shown in Tables 3 and 4, respectively. The mixture was mixed using a kneader at 40% under reduced pressure for 10 minutes to obtain an epoxy resin composition. The sealing of semiconductor elements for heat resistance reliability evaluation and the molding of test pieces for mechanical and electrical property evaluation were carried out at 180℃, 2
After curing for 1 minute, after-curing was carried out at 180°C for 6 hours. The results of evaluating the glass transition point, flexural modulus, electrical conductivity, and moisture resistance of the obtained compositions are shown in Table 5 (Examples) and Table 6 (Comparative Examples), respectively. The glass transition point was determined using a viscoelastic spectrometer (1
The temperature change in the loss modulus was measured at Hz), and the temperature that gave the maximum loss modulus was determined. The electrical conductivity of the test piece was measured at 121℃, 2atm, and 100% relative humidity.
Pressure Cooker Test (PCT) and 1000
Evaluation was made using the value obtained when 500 V DC was applied to the sample over time. Moisture resistance was evaluated by subjecting the semiconductor element for moisture resistance evaluation to PCT under the above conditions and determining the failure occurrence time.

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〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an epoxy resin composition for semiconductor encapsulation that has excellent moisture resistance reliability and excellent mechanical properties and electrical properties.

Claims (1)

[Scope of Claims] 1. An epoxy resin composition for semiconductor encapsulation which essentially comprises an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler treated with a silane coupling agent, wherein the inorganic filler The following general formula ()
One or more hydrophobic silane compounds represented by (a) RnSi(OR′) _4-o () and one or more silane coupling agents represented by the following general formula (b) YnSi(OR ') _4-o () (In both formulas, R represents an alkyl group or a phenyl group, R' represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and Y represents a group having an epoxy group or an amino group. 1. An epoxy resin composition for semiconductor encapsulation, characterized in that an epoxy resin composition is used that has been treated with a valent organic group, and n is an integer of 1 to 3. 2 The weight mixing ratio of the silane compound (a) and the silane coupling agent (b) is in the range of silane compound (a)/silane coupling agent (b) = 0.1 to 10, and The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the coupling agent (b) is added in an amount of 3% by weight or less based on the inorganic filler. 3 The silane compound (a) represented by the general formula () RnSi(OR') _4-o () has at least 1
The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, which is a silane compound having two phenyl groups.