JPS63295620A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent mechanical strength, thermal shock resistance, heat resistance and moisture resistance, by blending a polyfunctional epoxy compd., a novolak phenolic resin and an inorg. filler with a specified amount of a thermoplastic liquid crystal polymer. CONSTITUTION:A polyfunctional epoxy compd. (A) such as a novolak, bisphenol A or a alicyclic epoxy resin, a phenolic novolak resin (B) in an amount of 0.8-1.2 OH equivalents per epoxy equivalent of the component A, and 20-80wt.% inorg. filler (C) such as a crystalline silica powder, an alumina powder, talc or glass fibers are blended and kneaded with 0.1-25wt.% thermoplastic liquid crystal polymer crushed into a fibrous material with l/d>=20 (wherein l is the fiber length and d is the fiber diameter) using e.g., a Henschel mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel epoxy resin composition for semiconductor encapsulation which is blended with a thermoplastic liquid crystal polymer and has excellent thermal shock resistance, heat resistance and moisture resistance.

[Conventional technology and its problems] At present, resin encapsulation methods are widely used to encapsulate IC1LSI and other semiconductor devices using silicone resin or epoxy resin. Of these, epoxy resin has relatively excellent airtightness. It is widely used as a resin for semiconductor encapsulation because it provides high performance and is inexpensive.

However, due to the increasing use of IC and LSI mounting methods, resin-sealed packages tend to be smaller and thinner, and if smaller and thinner packages are made using conventional epoxy resin, Due to the low mechanical strength of epoxy resin, cracks occur in the sealing resin after it is dipped into solder. Therefore, in order to prevent this crack, a rubber component is dispersed in the epoxy matrix (for example, Japanese Patent Application Laid-Open No. 62-22824).
In order to reduce the coefficient of linear expansion, methods such as increasing the amount of inorganic filler added are being considered.

If the method of dispersing the rubber component in the epoxy matrix is adopted, the stress induced by the sealing resin being dipped into the solder is reduced, and the occurrence of cranking is reduced. Since the mechanical strength of the Ic is reduced, problems such as a reduction in long-term reliability and the occurrence of package cracks during the Ic assembly process occur.

On the other hand, in order to increase the amount of the inorganic filler added and reduce the expansion coefficient, the amount of the inorganic filler added must be 80% (wt%, the same shall apply hereinafter) or more. The viscosity increases and the fluidity decreases significantly, and further high-pressure molding is required when sealing the device. Furthermore, the increase in melt viscosity causes wire flow and wire breakage during molding, resulting in unfavorable conditions.

[Problems to be Solved by the Invention] The present invention has been made to solve these problems, and by increasing the mechanical strength of the sealing resin, even if it is eroded by dipping into the solder, The purpose of this invention is to provide an epoxy resin composition for semiconductor encapsulation that has excellent heat resistance, moisture resistance, etc., and does not damage the package.

Means for Solving Problem E] The present invention is a resin composition containing a polyfunctional epoxy compound, a phenol novolac resin, an inorganic filler, and a thermoplastic liquid crystal polymer. It relates to an epoxy resin composition for semiconductor encapsulation characterized by containing 0.1 to 25% by weight of.

[Example] The epoxy resin composition for semiconductor encapsulation of the present invention comprises a polyfunctional epoxy compound, a phenol novolak resin, an inorganic filler, and a thermoplastic liquid crystal polymer.

Examples of the polyfunctional epoxy compound used in the present invention include various types of epoxy resins such as novolak epoxy resin, bisphenol A epoxy resin, and alicyclic epoxy resin. Among these, novolac epoxy resin is preferable because it has excellent high-temperature properties. Note that these epoxy resins may be used alone or in combination of two or more.

The blending ratio of the polyfunctional epoxy compound and the 7-enol novolak resin is such that the OH equivalent of the phenol novolac resin is 0.8 per equivalent of the epoxy group of the polyfunctional epoxy compound.
It is preferable that it is 1.2 equivalents.

If the OH equivalent of the phenol novolak resin is less than 0.8 with respect to 1 equivalent of the epoxy group of the polyfunctional epoxy compound, the glass transition temperature of the composition will be low, and the moisture resistance and heat resistance will be reduced. Furthermore, if the OH ratio exceeds 1.2, a large amount of phenol novolac resin remains as an unreacted product in the cured product, resulting in a decrease in moisture resistance and heat resistance.

In addition to these epoxy resins, brominated novolac epoxy resins and brominated bisphenol A may be added as needed.
Epoxy resins such as mold epoxy resins may be used in combination.

In this case, the amount of these epoxy resins used is preferably 50 parts by weight or less based on 100 parts by weight of the polyfunctional epoxy resin.

The phenol novolac resin used in the present invention is obtained by condensing a phenolic compound such as phenol, cresol, xylenol, or bisphenol A lursorcin with formaldehyde or rose formaldehyde under an acidic catalyst, The monomer is 0 in the obtained phenolic novolak resin.
．． It is preferably 5% or less.

Examples of inorganic fillers used in the present invention include crystalline silica powder, fused silica powder, alumina powder, talc,
Examples include quartz glass powder, calcium carbonate powder, and glass fiber. These inorganic fillers are present in the composition between 20 and 8
Preferably, it is contained in an amount of 0%. If it is less than 20%, the effect of reducing linear expansion coefficient and curing shrinkage will be small, and if it exceeds 80%, fluidity will decrease and workability will tend to decrease. It is preferable to select the blending amount appropriately according to the following.

Examples of the thermoplastic liquid crystal polymer used in the present invention include a copolymer of polyethylene terephthalate-P-hydroxybenzoic acid and polyethylene terephthalate,
There are copolyesters made by melt polymerizing P-acetoxybenzoic acid, terephthalic acid, naphthalene diacetate, etc., and polyesters made of terephthalic acid, P-oxybenzoic acid, and p, p'-biphenol. Liquid crystal polymers exhibiting thermoplastic properties can be used.

The thermoplastic liquid crystal polymer is a molten type liquid crystal polymer, and fibrous or pellet-like polymers are used. Preferably, when the mH diameter is d1 and the fiber length is 1, j)
/d=20 or more.

The thermoplastic liquid crystal polymer has a ratio of 0.1 to the resin composition.
It must be contained at ~25%; if the content is less than 0.1%, the effect of improving mechanical strength will be small;
If it exceeds 5%, the resulting composition will have poor fluidity and workability, making it unsuitable for practical use.

The epoxy resin composition for semiconductor encapsulation of the present invention contains a polyfunctional epoxy resin, a phenol novolac resin, an inorganic filler, and a thermoplastic liquid crystal polymer as essential components, but may optionally include a coloring agent such as carbon black, carnauba wax, etc. , mold release agents such as polyethylene wax, flame retardants such as antimony trioxide, coupling agents such as γ-glycidoxy10-pyltrimethoxysilane, 1,8-diazabicyclo(5,4,0)undecene-7, triphenylphosphine. Various curing accelerators such as silicone rubber,
The content of a rubber component such as fluororubber in the composition is 10
It may be added within a range not exceeding %.

Further, the epoxy resin composition for semiconductor encapsulation of the present invention can be easily prepared using commonly used and known mixing equipment, such as a roll, a kneader, a Raikai machine, a Henschel mixer (manufactured by Mitsui Miike Seisakusho), etc. Can be done.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited only to these Examples.

Examples 1 to 6 and Comparative Examples 1 to 3 - Polyfunctional epoxy compound, phenol novolak resin, inorganic filler, thermoplastic liquid crystal polymer pulverized into fibers with a Henschel mixer (fiber diameter d, [N/d-°2G or more when % miscellaneous length ρ) and other ingredients are prepared, and rolled with a hot roll at 70 to 100°C.
After kneading for minutes, the diameter is 45 aw and the height is 20 to 35 aw+.
Tablets were formed using a press so that the bulk density was 1.4 to 1.1.

The next tablet was placed at a temperature of 180°C and a pressure of 80k.
(1/cIi was added for 2 minutes and transfer molded to produce a monitor chip for moisture resistance reliability evaluation and various evaluation specimens.Then, the various evaluation specimens obtained were
Post-curing was carried out for 8 hours at °C.

Next, the flexural modulus, flexural strength, linear expansion coefficient, glass transition temperature, and fluidity were measured using the various evaluation specimens obtained. The results are shown in Table 2.

Margin below E] Comparative Example 3 had poor fluidity, and it was not possible to prepare test pieces for various evaluations.

In addition, using the obtained monitor chip for evaluation of moisture resistance reliability, a moisture resistance test and a crack resistance test after solder dipping were performed using the following methods. The results are shown in Table 3.

(Moisture resistance reliability test) PCT (Pressure Cooker Te5t
), the time until failure occurred was measured under the conditions of 121°C and 2 atm.

(Crack Resistance Test) After 15 cycles of immersion in a solder bath at 260°C and liquid nitrogen at -196°C for 30 seconds each, the number of specimens with package cracks was counted.

Margin below E] Table 3 As can be seen from Table 2, when the epoxy resin composition for semiconductor encapsulation of the present invention is used, the characteristic properties such as glass transition humidity and coefficient of linear expansion, and the composition's It can be seen that the strength can be improved without significantly changing the fluidity, and as can be seen from Table 3, the crack resistance after thermal cycling is also very good.

[Effects of the Invention] As described above, since the epoxy resin composition for semiconductor encapsulation of the present invention contains a thermoplastic liquid crystal polymer, it has excellent mechanical strength, crack resistance after thermal cycling, heat resistance, and moisture resistance. Since it has properties, it can be advantageously used as a semiconductor sealing resin for ICs, LSIs, and the like.

Claims (1)

[Claims] (1) A resin composition containing a polyfunctional epoxy compound, a phenol novolak resin, an inorganic filler, and a thermoplastic liquid crystal polymer, and the thermoplastic liquid crystal polymer is contained in an amount of 0.1 to 25% by weight based on the resin composition. An epoxy resin composition for semiconductor encapsulation characterized by: