JPH0637542B2 - Epoxy resin composition for encapsulation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sealing epoxy resin composition. More specifically, the present invention relates to an electric / electronic component,
In particular, the present invention relates to an epoxy resin composition having good moisture absorption solder crack resistance and moldability as a semiconductor sealing resin.

(Prior art) Conventionally, as a sealing method for electric / electronic parts such as diodes, transistors, and integrated circuits, a resin sealing method using epoxy resin or silicon resin, or a hermetic method using glass, metal, ceramic, etc. has been adopted. Has been done. Among these methods, recently, a resin encapsulation method by low-pressure transfer molding using an epoxy resin, which has advantages in terms of mass production and cost as well as reliability improvement, has become mainstream.

In the encapsulation method using this epoxy resin, a molding compound composed of a composition in which an o-cresol novolac type epoxy resin or a bisphenol type epoxy resin is mixed with a phenol novolac resin as a curing agent component or an inorganic filler is used. It is used a lot.

(Problems to be Solved by the Invention) However, in recent years, the degree of integration of electronic parts such as ICs, LSIs, VLSIs, etc. has been increasing, and there is a tendency for higher densification. With the conventional epoxy resin molding materials, it is the actual situation that the predetermined sealing characteristics cannot be satisfied with the reduction in thickness.

For example, in a surface mounting device, it is rare that the device itself is rapidly exposed to a high temperature environment by directly immersing the device itself in solder. Therefore, the problem of package cracking is unavoidable. This is because moisture absorbed during storage after molding is rapidly vaporized and expanded when exposed to high temperatures, and the sealing resin cannot withstand this and cracks occur.

Although the occurrence of such cracks can be suppressed to some extent by using a bisphenol type resin as the epoxy resin, it is still insufficient as an effect of suppressing solder cracks after moisture absorption. There was also a problem that the occurrence was unavoidable.

This invention has been made in view of the circumstances as described above, eliminates the drawbacks of the resin encapsulating molding material so far, and suppresses moisture absorption solder cracking resistance to suppress the occurrence of package cracks due to solder immersion after moisture absorption. It is an object of the present invention to provide an epoxy resin composition which is excellent in moldability and has good moldability without generation of burrs during molding.

(Means for Solving the Problems) In order to solve the above problems, the present invention has a skeleton represented by the following formula (I): (R ₁ and R ₂ represent either a hydrogen atom or a C ₁ -C ₄ alkyl group) in the novolac bisphenol epoxy resin in an amount of 0.3 to 3.0 equivalents relative to 1 mol of the epoxy group. The total amount of silica containing 0.1 to 10% by weight of spherical silica having a particle size of 3.0 μm or less together with the curing agent is 50%.
Provided is an epoxy resin composition for encapsulation, which is blended in a proportion of from 90 to 90% by weight.

The present invention also provides, as the above-mentioned formula (I) epoxy resin,
It is also an embodiment to use a resin obtained by reacting a phenol novolac resin or an alkylphenol novolac resin with bisphenol glycidyl ether. In this case, bisphenol glycidyl ether is
For example, the following formula (II) Can be shown as And, in the composition of the present invention,
It is possible that the bisphenol glycidyl ether of the above formula (II) is present as a monomer after the reaction by remaining or the like.

Examples of the alkylphenol novolac resin include cresol novolac resin.

In the reaction of the above-mentioned phenol novolac resin or alkylphenol novolac resin with bisphenol glycidyl ether, a catalyst such as phosphine may be used if necessary, and the reaction may be carried out by heating.

As the epoxy resin curing agent, phenol novolac resin, cresol novolac resin, tetrahydrophthalic anhydride and the like are used, and phenol novolac resin is exemplified as a preferable one. The composition of this curing agent is
0.3 to 3.0 per 1 mol of the epoxy group of the above epoxy resin
The amount is equivalent, more preferably 0.6 to 1.5 equivalent. This amount is 0.
If it is less than 3 equivalents or more than 3.0 equivalents, moisture absorption solder crack resistance, moisture resistance, moldability and electrical properties of the cured product deteriorate, which is not preferable.

In the composition of the present invention, silica is added together with these curing agents in a proportion of 50 to 90% by weight based on the total amount of the curing agent. If it is less than 50% by weight, moisture absorption solder crack resistance, moisture resistance and mechanical properties are poor, and if it exceeds 90% by weight, moldability is poor and it is not suitable for practical use.

In addition, spherical silica is effective as this silica in order to suppress the occurrence of burrs during molding, and in particular, the particle diameter is 3.0 μm.
0.1 to 10% by weight, and more preferably 0.5 to 7% by weight, of spherical silica of m or less is contained.

When the spherical silica particles having a particle diameter of 3.0 μm or less are 0.1% by weight or less, the burr-inhibiting hardening is relatively small, and 1
A blending amount of 0% by weight or more is not preferable because the resin flow decreases.

Of course, the composition of the present invention may be used in combination with other types of epoxy resins as long as it does not hinder the achievement of the object, and known curing aids, talc, alumina, silicon nitride, aluminum hydroxide and the like. An inorganic filler, a mold release agent, a flame retardant, a pigment, a coupling material and the like may be appropriately added and blended. The composition may be molded by a conventionally known method such as transfer molding, injection molding, or compression molding.

Hereinafter, the composition of the present invention will be described in more detail with reference to Examples.

Examples 1-2 Phenolic novolac resin (softening point 80 ° C.) 10 parts, glycidyl ether of the following formula 90 parts and 0.1 parts triphenylphosphine,
The mixture was heated and mixed at a temperature of 150 ° C. for 2 hours.

Generation of novolac bisphenol epoxy resin was confirmed by NMR. Further, it was confirmed by GPC that 63% by weight of bisphenol glycidyl ether remained as a monomer. The epoxy equivalent was 255.

This resin was blended and kneaded with the composition shown in Table 1 together with fused silica having a spherical silica 3.0 μm diameter content of 7% by weight to prepare a resin composition. Mixing with a Kimisa, blender, etc. and kneading with a kneader, roll, etc. are performed. Further, if necessary, it may be solidified by cooling and crushed into particles.

The characteristics of the obtained composition as a molding material were evaluated. Table 1 shows the results.

The evaluation method was as follows.

(1) Burr generation Judgment is based on burrs between leads during 60pQFP TEG molding.

(2) Material viscosity 150 ° C., mono-hole method (3) Adhesion degree Adhesion on the backside of the die phat of 60 pQFP TEG was judged by ultrasonic image processing. The product having peeling was regarded as a defective product, and the ratio of good product to the defective product was shown.

(4) Number of seconds for crack generation After 60 pQFP TEG was humidified at 85 ° C. × 85% RH × 72H, it was immersed in solder at 260 ° C., and the number of seconds for crack generation was measured. Also, in this case, the products judged to be non-defective by the adhesion test were evaluated.

(Note) 60 pQFP (Dumpat size 8.2 mm × 8.2 mm) As is clear from the results of Table 1 and comparison with Comparative Examples described later, in Examples 1 and 2, moisture absorption solder crack resistance and moldability It was good.

Examples 3 to 4 The reaction was performed in the same manner as in Examples 1 to 2 except that the ratio of the phenol novolac resin to the glycidyl ether in Examples 1 to 2 was changed to 30 parts / 70 parts, and 340 novolaks having an epoxy equivalent of 340 were used. A bisphenol epoxy resin was obtained. This product contains 38 glycidyl ether monomers.
% By weight remained.

A molding material was produced with the compounding ratio shown in Table 1, and Examples 1-2
The characteristics were evaluated in the same manner as in. Excellent resistance to moisture absorption solder cracks and moldability.

Comparative Examples 1 to 2 Orthocresol novolac resin (Comparative Example 1) and the glycidyl ether (Comparative Example 2) used in Examples 1 to 4 were each compounded without compounding the novolac bisphenol epoxy resin of the present invention. The product was manufactured and its characteristics were evaluated in the same manner as in the example.

As shown in the results in Table 1, in the case of the novolac resin blend of Comparative Example 1, the moldability was good, but the moisture absorption solder crack resistance was inferior, and in the case of the glycidyl ether blend of Comparative Example 2, conversely. Burrs were unavoidable. The crack generation was not sufficiently suppressed.

Examples 5 to 7 Using the same novolak bisphenol epoxy resin as in Examples 1 to 2, epoxy resin compositions having the formulations shown in Table 2 were produced.

In this case, it was manufactured by changing the content of spherical silica having a particle size of 3.0 μm or less. About the obtained composition, Examples 1-2
The characteristics were evaluated in the same manner as in.

Note that only the burr generation is performed by the following method according to the first embodiment.
Evaluation was made differently from ~ 2.

<Evaluation of Burr Generation> A 60 pQFP mold was provided with a slit of 10 μm, and the burr generation was judged by this.

The results are shown in Table 2.

The moisture absorption resistance to solder cracking was improved and the effect of suppressing burr formation was excellent.

Comparative Examples 3 to 4 Example 5 was also applied to the case of using crystalline silica containing no spherical silica as the inorganic filler and the case of using fused silica containing 15% by weight of spherical silica having a diameter of 3.0 μm or less.
The performance was evaluated in the same manner as in .about.7.

With crystalline silica, the effect of suppressing the formation of burrs is not sufficient, and when added at a high rate of 15%, the viscosity of the resin becomes too large.

(Effect of the Invention) According to the present invention, as described in detail above, an epoxy resin composition excellent in both moisture absorption solder crack resistance and moldability can be obtained. Burr formation during molding is also effectively suppressed.

A good composition is realized as a resin molding material for sealing.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hirohiko Kagawa 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A 64-65116 (JP, A) JP-A 64-116 ( JP, A) JP 57-155226 (JP, A) JP 59-19330 (JP, A)

Claims (3)

[Claims] 1. A skeleton having the following formula (I) (R ₁ and R ₂ represent either a hydrogen atom or a C ₁ -C ₄ alkyl group) in the novolac bisphenol epoxy resin in an amount of 0.3 to 3.0 equivalents relative to 1 mol of the epoxy group. The total amount of silica containing 0.1 to 10% by weight of spherical silica having a particle size of 3.0 μm or less together with the curing agent is 50%.
The epoxy resin composition for encapsulation is characterized by being blended in a proportion of from 90 to 90% by weight. 2. The epoxy resin composition for sealing according to claim 1, wherein the novolak-bisphenol epoxy resin of the formula (I) is obtained by reacting a phenol novolac resin or an alkylphenol novolac resin with bisphenol glycidyl ether. 3. The epoxy resin composition for sealing according to claim 2, which contains a bisphenol glycidyl ether monomer.