JPH09302201A - Epoxy resin composition for hermetic sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relatively inexpensive epoxy resin composition for hermetic sealing which has excellent moisture resistance and, even when used for sealing a 1-mm or narrower gap, has sufficient sealing performance under high- humidity conditions, and which has significantly improved impermeability to water. SOLUTION: A bisphenol A epoxy resin having an epoxy equivalent of 200 or lower is mixed with a phenol-novolak epoxy resin in a weight ratio of 1.2:0.8 to 0.8:1.2 or with a cresol-novolak epoxy resin in a weight ratio of 1.4:0.8 to 1.0:1.2. A polyvinyl butyral resin is incorporated into the mixture in an amount of 2-6wt.% based on all the resins on a solid basis.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition used for hermetically sealing a ceramic package or the like. More specifically, the present invention relates to an epoxy resin composition for hermetic sealing, which has excellent moisture resistance and excellent moisture-resistant adhesion and water permeation resistance even in a narrow sealing width of 1 mm or less.

[0002]

2. Description of the Related Art Electronic components such as semiconductor elements (IC chips) are to be completely enclosed in order to shield them from the external environment and protect them from mechanical shock, and at the same time to facilitate handling and assembly. Often used in the form of a sealed package. The encapsulation method includes an airtight encapsulation method in which airtightness is maintained with metal or ceramic, and a resin encapsulation method in which the periphery of the chip is surrounded by resin (mainly a composition in which a large amount of filler is mixed with epoxy resin) by transfer molding There is a stop.

A ceramic package using ceramic as an encapsulant is more expensive than a resin-encapsulated package, but the encapsulant has good thermal conductivity, and the heat dissipation of heat generated by a chip during operation is good. It has features such as high heat resistance, good dimensional stability, no hygroscopicity, strong humidity, and perfect sealing.

Therefore, the ceramic package is mainly used in fields such as large-sized computers, space equipment / military equipment requiring high reliability, high power used in an environment where resin encapsulation cannot withstand, and automobiles. Has been used.
Furthermore, in response to the demand for miniaturization and high performance of electronic parts, I
As the degree of integration of C chips has increased and the amount of heat generated has increased, ceramic packages with excellent heat dissipation have also been adopted for consumer computers and the like.

Further, a crystal oscillator used in an oscillator of a mobile phone or the like is often used as a ceramic package in which the periphery is surrounded by a ceramic and sealed like the IC ceramic package.

The ceramic package is sealed by mounting a sealing material such as an IC chip or a crystal oscillator on a ceramic substrate, then covering the cap (lid) of the housing and bonding it to the substrate with a sealing material. To be done. Similar to the substrate, the cap is often made of ceramic, but a metal cap is also used in some cases.

As a sealing material for sealing a ceramic package (bonding a substrate and a cap), a brazing material such as Au—Sn, a solder alloy, glass, a resin or the like has been used.
The Au-Sn brazing encapsulation method is the most excellent in terms of encapsulation reliability, but for consumer use, lowering production costs is also an important issue. The resin encapsulation method, which enables encapsulation at low temperature, has the lowest price. For this reason, a ceramic package sealed with a resin is becoming popular especially for a crystal unit.

The resin sealing material used for joining the ceramic substrate and the cap in the ceramic package is
Similar to the encapsulant for resin encapsulation packages of IC chips, epoxy resin, especially novolac type epoxy resin, is mainly used. This sealing resin has the performance required for sealing,
For example, durability of adhesive strength and moisture resistance are required.

In order to improve these performances of conventional epoxy resins (epoxy resin mixed with a curing agent), a homogeneous polymer blend type or heterogeneous sea-island structure in which epoxy resin is mixed with a small amount of thermoplastic resin It is known to use resin compositions which consist of a mixture of molds.

[0010]

As electronic components are further miniaturized, the sealing width of ceramic packages has become narrower, and conventional epoxy resins for encapsulation are no longer available.

For example, the sealing width of the crystal unit is 0.7 mm or less, and with this sealing width, the time for airtight sealing in the high temperature and high humidity test (pressure / cooker test, abbreviated as PCT) (until resin peels) Moisture-proofness of the conventional sealing epoxy resin is insufficient, which is less than 8 hours.
Conventionally, the sealing width is typically as wide as 2 mm or more, so that the moisture-tightness of the PCT is kept at 25 to 50 hours.

When the epoxy resin is blended with the thermoplastic resin, the hermetic sealing time in the PCT may be extended to 50 hours or more even if the sealing width is as narrow as 1 mm or less. However, it has been found that even if the adhesiveness is maintained by the blending of the thermoplastic resin, the amount of water permeating through the resin during that time is large, so that moisture penetrates into the package and the reliability of the package decreases.

Therefore, even if the sealing width is narrowed to 1 mm or less, it exhibits excellent moisture-tightness and at the same time has excellent water permeation resistance and a small amount of water permeation under PCT conditions. There is a need for an epoxy resin composition for tight sealing. In addition, it is desirable to use only a relatively inexpensive material as a component of the encapsulating material because of the strong demand for cost reduction of electronic components.

The object of the present invention is to provide excellent moisture resistance, sufficient moisture tightness even with a narrow sealing width of 1 mm or less, excellent water permeation resistance, and a very small amount of water permeation under PCT conditions. An object is to provide a relatively inexpensive epoxy resin composition for hermetic sealing.

[0015]

Means for Solving the Problems As a result of continuous research to achieve the above object, the present inventors have found that when a small amount of polyvinyl butyral resin is added to an epoxy resin, the moisture tightness of the epoxy resin is improved. Then, in an epoxy resin composition containing a small amount of polyvinyl butyral resin, it was found that the water permeation resistance is remarkably improved by mixing and using two kinds of epoxy resins having different structures within a specific range, The present invention has been reached.

In the present invention, (A) a phenol novolac type epoxy resin and a bisphenol A type epoxy resin having an epoxy equivalent of 200 or less are 1.2: 0.8 to 0.8: 1.2.
In the epoxy resin compounded in a weight ratio of, or in the epoxy resin compounded with the cresol novolac type epoxy resin and the above bisphenol A type epoxy resin in a weight ratio of 1.4: 0.8 to 1.0: 1.2, (B) total resin solid content Based on 2 to 6% by weight of polyvinyl butyral resin,
It is an epoxy resin composition for hermetic sealing.

In a preferred embodiment, an epoxy resin is used as a curing agent in two components of 4 to 6% by weight of dicyandiamide and 3 to 5% by weight of an aromatic polyamine, or in addition to these two components, triphenylphosphines 1 to 4 are further added. It contains 3 components blended in wt%. Further, the epoxy resin composition of the present invention comprises an organic solvent that does not dissolve dicyandiamide, 3% by weight or less of silicic acid anhydride based on the total resin solid content, and 1 to 4% by weight of a silane cup based on the total resin solid content. You may further contain 1 type (s) or 2 or more types of ring agents.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
In the following description, parts and% are parts by weight and% by weight, unless otherwise specified.

(A) Epoxy resin In order to obtain moisture-resistant adhesive strength and heat resistance, a novolac type epoxy resin having a large number of functional groups is used. As the novolac type epoxy resin, both cresol novolac type and phenol novolac type novolac type epoxy resins can be used. However, since the crosslink density does not increase only with the novolac type epoxy resin, it has a different molecular structure.
The crosslink density is adjusted by using a functional bisphenol A type epoxy resin together.

As the bisphenol A type epoxy resin, a liquid epoxy equivalent of 200 or less at room temperature, typically a bisphenol A diglycidyl ether type epoxy resin is used. Examples of commercially available products include Epicoat 828 manufactured by Shell and Araldite GY260 manufactured by Ciba Geigy. If the epoxy equivalent of the bisphenol A type epoxy resin exceeds 200, the water permeation resistance decreases.

The compounding ratio (weight ratio) of the novolac type epoxy resin to the bisphenol A type epoxy resin is 1.2: 0.8 to 0.8: 1 for the phenol novolac type epoxy resin.
2, preferably in the range of 1.1: 0.9 to 0.9: 1.1, 1.4: 0.8 to 1. for cresol novolac type epoxy resin.
It is within the range of 0: 1.2, preferably 1.3: 1.1 to 0.9: 1.1. That is, when a phenol novolac type epoxy resin having an epoxy equivalent smaller than that of the cresol novolac type epoxy resin is used, the compounding amount may be smaller.

The mixing ratio of the novolac type epoxy resin and the bisphenol A type epoxy resin is determined as described above, as shown in Examples later, when a small amount of polyvinyl butyral resin is mixed, these two types of epoxy This is because the water permeation resistance is remarkably improved only when the blending ratio of the resin is within the above range, and the effect of improving the water permeation resistance is hardly recognized outside the range.

(B) Polyvinyl butyral resin Polyvinyl butyral resin (hereinafter referred to as “butyral resin”) is obtained by condensing polyvinyl alcohol (PVA) obtained by saponification of polyvinyl acetate with butyraldehyde.
It is a thermoplastic resin obtained by (butyralization). It is also possible to carry out saponification and butyralization of polyvinyl acetate at the same time.

There are various kinds of butyral resins, depending on the saponification degree of the raw material polyvinyl acetate and the degree of butyralization of the intermediate polyvinyl alcohol. The butyral resin used in the present invention has a butyralization degree of 70 to 74 mol%, a residual hydroxyl group amount of 24 to 28 mol%, a residual acetyl group amount of 1.5 to 2.5 mol%, and a glass transition temperature of about 280 ° C. Is preferred.

Here, the amount of residual acetyl groups is the ratio of unsaponified acetyl groups, the amount of residual hydroxyl groups is the ratio of acetyl groups that are saponified but not butyralized, and the degree of butyralization is saponification. And the butyralized acetyl groups (both mol% relative to the acetyl groups present in the raw material polyvinyl acetate).

The above-mentioned epoxy resin (A) has insufficient cohesive force when cured with an ordinary curing agent, and the curing agent remains unreacted. Therefore, when the sealing width becomes narrower than 1 mm, the moisture resistance is Is significantly reduced. The butyral resin blended with the epoxy resin (A) in the present invention is completely compatible with the epoxy resin (A) and does not separate from the epoxy resin even when cured, and mixes homogeneously with the epoxy resin. Further, since a large proportion of hydroxyl groups (OH groups) that react with epoxy groups remain in this butyral resin, it functions as a curing agent for the epoxy resin and chemically bonds with the epoxy resin during curing.

When the butyral resin is polymer-blended with the epoxy resin in this manner, and the thermoplastic butyral resin is homogeneously dissolved in the hard epoxy resin and bonded to the molecules of the epoxy resin, the cohesive force of the epoxy resin increases, It has been found that the moisture tightness is dramatically increased.

The butyral resin may be incorporated in a small amount of 2 to 6%, preferably 3 to 5%, based on the total resin solid content. If the content of the butyral resin is less than 2%, the effect of improving the moisture tightness will not be sufficiently exhibited, and if it exceeds 6%, the properties of the butyral resin will be strongly exhibited and the moisture tightness will be deteriorated. The total resin solid content means the total amount of the epoxy resin and its curing agent and other resins.

(C) Epoxy curing agent A known epoxy curing agent necessary for curing an epoxy resin is added. As the epoxy curing agent, it is preferable to use one or more curing agents whose curing reaction at room temperature is slow and substantial curing does not start unless heated to a considerably high temperature. If the epoxy resin cures immediately at room temperature, the substrate and the cap can be bonded, but a good meniscus shape is required for hermetic sealing [a trapezoidal cross-sectional shape that expands downward as shown in Fig. 1 (C)]. It is not possible to form a sealing portion having the shape of, for example, a sealing portion having a circular meniscus shape and having a reduced hermetic sealing property.

Preferred curing agents are aromatic diamines (eg, diaminodiphenylmethane, diaminodiphenylsulfone, metaphenylenediamine, etc.), which have a slow curing reaction at room temperature, and dicyandiamide, which also has a slow reaction at room temperature and excellent latency. It is a two-component mixture, and a three-component mixture in which triphenylphosphine is further added to this mixture. Triphenylphosphine has the effect of preventing bleeding due to the difference in the reaction rate of the resin during curing.

When a curing agent composed of the above mixture is used, the addition amount thereof is 4 to 6% by weight of dicyandiamide, 3 to 5% by weight of aromatic polyamine, and triphenylphosphine, based on the total amount of the epoxy resin and the curing agent. It is preferably in the range of 1 to 4% by weight.

(D) Organic solvent It is preferable to use an organic solvent in order to facilitate mixing of the two kinds of epoxy resins and the butyral resin. The organic solvent is selected with care so as not to accelerate the curing reaction of the epoxy resin at room temperature.

When the above two-component or three-component mixture is used as the epoxy curing agent, it is preferable to use an organic solvent that does not dissolve dicyandiamide in the curing agent. When dicyandiamide dissolves in a solvent, its latent property is lost and the curing reaction at room temperature is accelerated, the pot life (pot life) in the B stage state becomes very short, the workability deteriorates, and the meniscus shape (Thus, the hermetic sealing property) is also poor.

A preferred example of the organic solvent that does not dissolve dicyandiamide is a cellosolve solvent. Considering workability, methyl, ethyl or isopropyl cellosolve acetate is preferable as the organic solvent. The amount of the solvent used is preferably in the range of 20 to 50% by weight based on the total resin solid content.

(E) Filler A very small amount of anhydrous material is added in order to improve airtight sealing property and impart thixotropic property to the resin composition so that a good meniscus-shaped sealing part can be easily formed. It is preferable to incorporate silicic acid as a filler. As the silicic acid anhydride, those having an average particle diameter of 12 to 20 nm are particularly preferable.

The compounding amount of the filler is 3 with respect to the total resin solid content.
% Or less, preferably 0.5 to 2%. Since the silicic acid anhydride is extremely fine, if it is added in a large amount, the fluidity of the resin in the B stage state is hindered, and the meniscus shape of the sealing portion becomes poor. The filler is not limited to silicic acid anhydride, and other fillers (for example, titanium oxide) can be used.

(F) Silane Coupling Agent When a small amount of a silane coupling agent is added as a wetting agent, the wettability of the epoxy resin composition is enhanced, and the coating operation with a narrow sealing width is facilitated. As the silane coupling agent, those containing an epoxy group [eg, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc.] are particularly preferable. A preferred silane coupling agent is Shin-Etsu Chemical Co., Ltd. KBM-403. The blending amount of the silane coupling agent is
It is 1 to 4%, preferably 2 to 3% with respect to the total resin solid content.

The epoxy resin composition of the present invention may contain one or more additives in a small amount, in addition to the above components. As such an additive, a curing catalyst,
There is a coloring agent.

The composition of the present invention is prepared, for example, by heating an epoxy resin and a butyral resin in a solvent (eg, 90 ± 5 ° C.).
After 30 to 40 minutes), the mixture is completely dissolved, cooled to 25 to 30 ° C., the curing agent and other components are added at this temperature, and the mixture can be prepared by kneading using a three-roll at room temperature.

The epoxy resin composition for hermetic sealing of the present invention is suitable for sealing a ceramic package, but can also be used for sealing a metal package, and also for protecting a pattern on the surface of a ceramic substrate. Materials that can be sealed with the epoxy resin composition of the present invention include alumina, cordierite, mullite, glass ceramic, ceramics such as aluminum nitride, nickel, cobalt, 42 alloy, gold,
Examples include metals such as copper and plastics such as epoxy and polyimide.

At the time of use, the epoxy resin composition is applied to the adhesion portion of the substrate or the cap which is the packaging material, or both of them (usually the cap) by a method such as screen printing, dispenser or transfer to a prescribed thickness, and then, Heat in a forced circulation oven to bring the resin to the B stage. This heating is carried out so that the solvent evaporates and the resin surface does not become sticky, but the resin remains curable and plastic. The heating temperature may be appropriately selected according to the type of resin and the type of curing agent. For example, when the curing agent is the above-mentioned two-component system or three-component system mixture,
About 2 to 4 hours at 85 ° C is suitable.

Thereafter, a packaged substrate such as an IC chip or a crystal oscillator is mounted on the substrate of the package material by an appropriate method, a cap is set on the substrate, and the substrate is heated under pressure to remove the epoxy resin. Once cured, the package encapsulation is complete. Curing is preferably carried out by heating at 155 to 165 ° C for 1.5 to 2.5 hours.

Since the epoxy resin composition of the present invention can be stored in the B stage for a considerable period of time,
For example, a packaging material manufacturer can apply the epoxy resin composition of the present invention to a packaging material, heat it to a B stage state, and then ship it. Thereby,
Since the package manufacturer can manufacture the package simply by mounting the IC chip and the crystal oscillator on the substrate and then heating the package under pressure, there is an advantage that a complicated epoxy resin coating operation can be omitted.

[0044]

Example 1 Phenol novolac type epoxy resin (epoxy equivalent 17
9) and any one of the other four epoxy resins shown in Table 1 so that the epoxy group concentration becomes almost equal (that is, the epoxy equivalent weight obtained by dividing the added amount by the epoxy equivalent becomes almost equal). 4% butyral resin based on the total solid content of the resin (degree of butyralization: 72 mol%, residual hydroxyl group: 26 mol%, residual acetyl group: 2.0 mol%, glass transition temperature: about 280 ° C) Was added. To 100 parts of this resin mixture was added 25 parts of methyl cellosolve acetate as a solvent, and the mixture was heated to 90 ± 5 ° C for 30-40 minutes to completely dissolve the resin in the solvent, and then 25-30 ° C. Cooled down.

To the cooled resin solution, 5% by weight of dicyandiamide, 4% by weight of diaminodiphenylmethane and 2.5% by weight of triphenylphosphine as hardener, based on the total amount of epoxy resin + hardener, based on total resin solids, were used. 2% silicic acid anhydride (average particle size 16 nm, filler) and 2% silane coupling agent (Shin-Etsu Chemical KBM-40
3, wetting agent) and uniformly mixed with three rolls at room temperature to prepare an epoxy resin composition.

Using this epoxy resin composition, the composition shown in FIG.
A test package was prepared as shown in (A) to (C). First, the ceramic with the shape shown in Fig. 1 (A).
After coating the resin composition to be tested on the (alumina) cap as shown in FIG. 1 (B), the resin was heated to 80 ± 2 ° C. for 3 hours to put the resin in the B stage state. After that, as shown in FIG. 1 (C), a cap coated with the resin composition was adhered to a transparent glass plate and heated at 160 ° C. for 2 hours to cure the epoxy resin to prepare a package.

As can be seen from the dimensions shown in FIG. 1 (A),
The wall thickness of the cap, and thus the sealing width, is 0.7 to 0.75 mm. The water permeation resistance of the sealing part of this test package is set to 80
It was evaluated by the presence or absence of dew condensation on the glass surface after being immersed in warm water of ± 2 ° C for 4 days. The test results are shown in Table 1 below, together with the types and epoxy equivalents of the other epoxy resins blended with the phenol novolac type epoxy resin (epoxy equivalent 179).

[0048]

[Table 1]

As shown in Table 1, when the bisphenol A type epoxy resin having an epoxy equivalent of 200 or less is added to the novolac type epoxy resin, the water permeation resistance is improved and the glass surface is immersed in warm water for 4 days. (Thus, no dew condensation was formed on the inside of the package.) However, when the epoxy equivalent of the bisphenol A type epoxy resin was larger than 200, there was no effect of improving the water permeation resistance. Also, bisphenol A
With epoxy resins other than the type epoxy resin, even if the epoxy equivalent was as low as 200 or less, there was no effect of improving the water permeation resistance.

As a novolac type epoxy resin,
Even when a cresol novolac type epoxy resin is used, a bisphenol A type epoxy resin having an epoxy equivalent of 189 is added to the cresol novolac type epoxy resin so that the epoxy group concentrations become almost equal, and an epoxy resin composition is prepared in the same manner as above. By doing so, it was confirmed in the above-mentioned water resistance test that good water permeation resistance was obtained without dew condensation on the glass surface after immersion in warm water for 4 days.

Example 2 The same procedure as in Example 1 was repeated except that a mixture of a phenol novolac type epoxy resin having an epoxy equivalent of 179 and a bisphenol A type epoxy resin having an epoxy equivalent of 189 was used as the epoxy resin. An epoxy resin composition was prepared and a test package was prepared.

For comparison, an epoxy resin composition and a test package were prepared in the same manner as in Example 1 except that no butyral resin was added.

The water permeation resistance was evaluated by immersing the package sealed with each composition in hot water at 80 ° C. until dew condensation was observed on the glass surface, and the number of days of dipping (number of days until dew condensation occurred) was evaluated. did. The test results are shown graphically in FIG.

On the other hand, when the butyral resin was blended, the water permeation resistance was remarkably improved when the weight ratio of the phenol novolac type epoxy resin and the bisphenol A type epoxy resin having an epoxy equivalent of 200 or less was around 1: 1, The water permeation resistance could not be improved even if the novolac type epoxy resin was used in a larger amount or in a smaller amount. That is, the effect of improving the water permeation resistance is that the phenol novolac type resin is
40-60%, bisphenol A type epoxy resin 60-40%
(The weight ratio of both is in the range of 1.2: 0.8 to 0.8: 1.2).

When the novolac type epoxy resin is the cresol novolac type, since the epoxy equivalent is larger than that of the phenol novolac type, the above-mentioned effect of remarkably improving the water permeation resistance can be obtained in the range of the weight ratio of novolac: bisphenol A. Is a little more novolak resin,
The range is 1.4: 0.8 to 1.0: 1.2.

On the other hand, in the conventional epoxy resin composition containing no butyral resin, even if the compounding ratio of the novolac type epoxy resin and the bisphenol A type epoxy resin is within the above range, as shown in FIG. The number of days until development was one day, and the water permeation resistance remained at a low level. That is, in order to obtain the effect of improving the water permeation resistance when the novolac type epoxy resin and the bisphenol A type epoxy resin are blended in the above proportions, it is necessary to blend the butyral resin together.

The moisture resistance of the test packages prepared in this Example was kept in a pressure cooker under high temperature and high humidity conditions of 2.09 atm, 121 ° C. and 100% relative humidity (steam saturation) for 75 hours. Presence or absence of subsequent gross leak (120
The presence or absence of foaming when immersed in CFC liquid at ℃) was determined, no gross leak was observed in any composition,
Moisture resistance was good.

[0058]

EFFECTS OF THE INVENTION The epoxy resin composition for hermetic sealing of the present invention is excellent in moisture tightness even with a narrow sealing width of 1 mm or less, and unlike other conventional epoxy resin compositions, it is water resistant. Since it is also excellent in permeability, moisture is prevented from permeating into the package, and the reliability of the package is greatly improved. Further, the raw material cost is the same as that of the conventional epoxy resin composition. Therefore, it is suitable for the demands for downsizing and cost reduction of the ceramic package, and the reliability of the package can be remarkably enhanced.

[Brief description of drawings]

1A to 1C are explanatory views showing a method for manufacturing a ceramic package manufactured in an example.

FIG. 2 is a graph showing the results of water permeation resistance test in Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 3/34 NLC C08K 3/34 NLC 5/54 NKX 5/54 NKX H01L 23/10 H01L 23 / 10 B // (C08L 63/04 63:02 29:14)

Claims (6)

[Claims] 1. An epoxy resin comprising (A) a phenol novolac type epoxy resin and a bisphenol A type epoxy resin having an epoxy equivalent of 200 or less at a weight ratio of 1.2: 0.8 to 0.8: 1.2, and (B) all resins. 2 based on solids
An epoxy resin composition for airtight sealing, which contains 6% by weight of polyvinyl butyral resin. 2. An epoxy resin comprising (A) a cresol novolac type epoxy resin and a bisphenol A type epoxy resin having an epoxy equivalent of 200 or less at a weight ratio of 1.4: 0.8 to 1.0: 1.2, and (B) all resins. 2 based on solids
An epoxy resin composition for airtight sealing, which contains 6% by weight of polyvinyl butyral resin. 3. An epoxy resin as a curing agent, 4 to 6% by weight of dicyandiamide and 3 to 5 of an aromatic polyamine.
The epoxy resin composition according to claim 1 or 2, containing 4 to 6% by weight of dicyandiamide, 3 to 5% by weight of aromatic polyamine and 1 to 4% by weight of triphenylphosphine. 4. The epoxy resin composition according to claim 3, further comprising an organic solvent which does not dissolve dicyandiamide. 5. The epoxy resin composition according to claim 1, further containing 3% by weight or less of silicic acid anhydride based on the total resin solid content. 6. A silane coupling agent is further contained in an amount of 1 to 4% by weight based on the total resin solid content.
The epoxy resin composition according to any one of 1.