JPH0347827A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition suitable for a semiconductor sealing resin having excellent resistance to cracking by moisture absorption in solder and moldability by compounding a specific novolak.bisphenol epoxy resin, a curing agent for an epoxy resin and a inorganic filler. CONSTITUTION:A novolak.bisphenol epoxy resin having skeleton expressed by the formula (R1 and R2 are H, 1-4C alkyl) is mixed with a curing agent for an epoxy resin (preferably phenol novolak resin) and an inorganic filler (preferably 0.1-10wt.% spherical silica having <=3.0mum particle diameter) to afford the aimed composition.

Description

[Detailed description of the invention] (Industrial application field) TECHNICAL FIELD This invention relates to an epoxy resin composition.

More specifically, the present invention relates to an epoxy resin assembly having good moisture absorption solder crack resistance and moldability as a sealing resin for electrical/electronic parts, particularly semiconductors.

(Conventional technology) Conventionally, resin encapsulation methods using epoxy resins, silicone resins, etc., and hermetic methods using glass, metals, ceramics, etc. have been used as encapsulation methods for electrical and electronic components such as diodes, transistors, and integrated circuits. It has been done. Of these methods, resin encapsulation by low-pressure transfer molding using epoxy resin has recently become mainstream, as it has advantages in terms of improved reliability, mass production, and cost.

In this sealing method using an epoxy resin, the molding material is a composition that is a combination of an 0-cresol novolac type epoxy resin or a bisphenol type epoxy resin, a phenol novolac resin as a hardening agent component, and an inorganic filler. Relatively used.

(Problem to be solved by the invention) However, in recent years, the degree of integration of electronic parts such as ICs, LSIs, and VLSIs has increased, and there is a trend toward higher density, so there is a demand for thinner mold resins. However, the reality is that conventional epoxy resin molding materials cannot meet the required sealing characteristics in addition to this thinning.

For example, surface-mount devices are often exposed to sudden high-temperature environments, such as by directly immersing the device in solder during mounting. For this reason, the problem of package cracking was unavoidable. This is because moisture absorbed during storage after molding rapidly evaporates and expands when exposed to high temperatures, and the sealing resin cannot withstand this and cracks occur.

Although it is possible to suppress the occurrence of rack to some extent by using bisphenol type resin as the epoxy resin, it is still insufficient to suppress solder cracks after moisture absorption, and on the other hand, There was also the problem that the outbreak of Paris was inevitable.

This invention was made in view of the above-mentioned circumstances, and it eliminates the drawbacks of conventional resin encapsulation molding materials and provides moisture absorption solder crack resistance that suppresses 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 has excellent moldability and does not generate flakes during molding.

(Means for Solving the Problems) The present invention solves the above problems, and the present invention provides that, as the epoxy resin, phenol or alkylphenol novolac resin is replaced with bisphenol glycidyl ether. It also includes the use of products obtained by reaction.

In this case, bisphenol glycidyl ether is, for example, a novolac bisphenol epoxy resin represented by the following formula (R and R2 represent either a hydrogen atom or a C3-C4 alkyl group), an epoxy resin curing agent, and an inorganic filler. Provided is an epoxy resin composition comprising:

Hz It is also possible to remain as a monomer represented by

This bisphenol glycidyl ether may be formulated as a polymer resin.

Examples of the alkylphenol novolak resin include bresol novolak resin.

The above reaction can be carried out by using a catalyst and heating if necessary.

As the epoxy resin curing agent, phenol novolak resin, cresol novolak resin, tetrahydrophthalic anhydride, etc. are used, and phenol novolak resin is exemplified as a preferable one. The composition of this curing agent is
0.3 to 1 mole of epoxy group in the above epoxy resin
The amount is 3.0 equivalents, more preferably 0.6 to 1.5 equivalents. If this amount is less than 0.3 equivalents or more than 3.0 equivalents, moisture absorption resistance to solder cracking, moisture resistance, moldability, and electrical properties of the cured product will deteriorate, which is undesirable.

In addition to these curing agents, conventionally known curing agents such as tertiary amines and phosphorus compounds can also be added.

Silica, talc, alumina, silicon nitride, aluminum hydroxide, etc. can be used as the inorganic filler to be mixed with these hardening agents.

Among these, silica is exemplified as preferred. These inorganic fillers have a content of 50 to 90% relative to the resin composition.
It is preferable to mix it in a proportion of % by weight. If it is less than 50% by weight, moisture absorption and solder crack resistance, moisture resistance, and mechanical properties will be poor, and if it exceeds 90% by weight, moldability will be poor and it is not suitable for practical use.

In order to suppress the generation of flakes during molding, spherical silica is effective as this inorganic filler, and in particular, 0.1 to 10% by weight, more preferably 0.1 to 10% by weight of spherical silica with a particle size of 3.0 μm or less. It is preferable to blend an inorganic filler containing 0.5 to 7% by weight.

Even for granular silica with a particle size of 3.0 μm or more or spherical silica with a particle size of 3.0 μm or less, the effect of suppressing the generation of paris is relatively small when the amount is 0.1% by weight or less, and when the content is 10% by weight or more If so, resin flow tends to decrease.

Of course, in addition to these, a release agent, a flame release agent, a pigment, a coupling material, etc. may be added and blended as necessary. Further, for molding the composition, conventionally known methods such as transfer molding, injection molding, or compression molding can be employed.

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

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

Formation of novolak bisphenol epoxy resin was confirmed by NMR. Furthermore, it was confirmed by GPC that 631% by weight of bisphenol glycidyl ether remained as a monomer.

The epoxy equivalent weight was 255.

This resin was mixed and kneaded using the formulation shown in Table 1 to obtain a resin composition. Mixing using a mixer, blender, etc., and kneading using a kneader, rolls, etc. are performed. Moreover, if necessary, it can be solidified by cooling and pulverized into granules.

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

The evaluation method was as follows.

(1) Paris generation: Determined by the Paris between the leads during 60pQFP TEG molding.

Material viscosity 150℃, monohole method adhesion 60p QFP TEG adhesion to the back side of Daihatsu was determined by ultrasonic image processing. Items with peeling are considered defective.
It is expressed as a percentage of non-defective products.

Crack generation time: 60 pQFP TEG at 85°C x 85% RH x 72H
After humidifying the sample at 260° C., the sample was immersed in solder at 260° C., and the number of seconds it took for cracks to occur was measured. Moreover, in this case, the evaluation was made on those determined to be good in the adhesion test.

(Note) 60pQFP (Die pad size 8.2n
(4) (2) (3) 0 As is clear from the results in Table 1 and the comparison with the comparative examples described below, in Examples 1 and 2, moisture absorption solder crack resistance It was also good in terms of moldability and moldability.

Examples 3-4 The reaction was carried out in the same manner as in Examples 1-2 except that the ratio of phenol novolac resin and glycidyl ether in Examples 1-2 was changed to 30 parts/70 parts, and the epoxy equivalent was 3400 novola.y. A bisphenol epoxy resin was obtained. This one contains 3 glycidyl ether monomers.
8% by weight remained.

Molding materials were manufactured with the compounding ratio shown in Table 1, and Examples 1 to 2
The characteristics were evaluated in the same manner. Both moisture absorption solder crack resistance and moldability were excellent.

Comparative Examples 1 to 2 Ortho-cresol novolac resin (
Comparative Example 1) and the glycidyl ether used in Examples 1 to 4 (Comparative Example 2) were blended to produce a resin composition, and the properties thereof were evaluated in the same manner as in the Examples.

As shown in Table 1, in the case of Comparative Example 1, which contains Noborazuk resin, the moldability is good, but the moisture absorption and solder crack resistance is poor, and in the case of Comparative Example 2, which contains glycidyl ether, the moldability is good. The outbreak of Paris was inevitable. The suppression of crack generation was also not sufficient.

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In this case, the content of spherical silica having a particle size of 3.0 μm or less as an inorganic filler was varied.

The properties of the obtained composition were evaluated in the same manner as in Examples 1 and 2.

In addition, only the Paris generation was performed in Example 1 by the following method.
~2 was evaluated differently.

Evaluation of burr formation> A 10 μm slit was provided in a 60p QFP mold, and burr formation was determined based on this.

The results are shown in Table 2.

It was excellent in both improving moisture absorption and solder cracking resistance and inhibiting the formation of paris.

Comparative Examples 3 to 4 Examples 5 to 4 also apply to cases where crystalline silica is used as the inorganic filler and cases where 15% by weight of granular silica is blended.
Performance was evaluated in the same manner as in 7.

14 Crystalline silica does not have a sufficient effect of suppressing Paris formation, and addition at a rate as high as 15% increases the viscosity of the resin too much.

5 (Effects of the Invention) As explained in detail above, the present invention provides an epoxy resin composition that is excellent in both moisture absorption solder crack resistance and moldability. Paris formation during molding is also effectively suppressed.

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

Claims (5)

[Claims] (1) The skeleton has the following formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_1 and R_2 are hydrogen atoms or C_1 to C_
An epoxy resin composition characterized by blending a novolak bisphenol epoxy resin represented by the following formula (representing any one of 4 alkyl groups) with an epoxy resin curing agent and an inorganic filler. (2) An epoxy resin composition comprising a novolak/bisphenol epoxy resin obtained by reacting a phenol novolac or alkylphenol novolac resin with bisphenol glycidyl ether, an epoxy resin curing agent, and an inorganic filler. (3) The epoxy resin composition according to claim (1) or (2), which contains a novolak bisphenol epoxy resin containing a bisphenol glycidyl ether monomer. (4) The epoxy resin composition according to claim (1), (2) or (3), wherein spherical silica is blended as the inorganic filler. (5) 0.1 to 10 spherical silica particles with a particle size of 3.0 μm or less
The epoxy resin composition according to claim 4, further comprising an inorganic filler containing % by weight of an inorganic filler.