JPH0611845B2 - Low radiation epoxy resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoxy resin composition in which the generation of radiation such as α-rays is extremely small, and its characteristic is a filler and flame retardant having a very small content of radiation impurities. Is in place.

<< Prior Art >> In recent years, epoxy resin molding materials for low-pressure molding have been most commonly used for sealing semiconductor elements such as ICs and LSIs. From the characteristics such as productivity and reliability cost aspect,
This is because it is the most balanced molding material and molding method.

It is expected that resin encapsulation of semiconductors will continue to progress in the future, but one of the problems that is currently emerging as a problem is soft error countermeasures.

In the case of highly integrated and multifunctional semiconductors, for example memory applications, the memory capacity is 16K → 64K → 256K → 1M ...
As it goes on, malfunctions due to radiation (α rays) = soft errors are more likely to occur. Therefore, the packaging material should also be one that produces a small amount of radiation.

At present, substances that may contain radioactive impurities in the epoxy resin composition include inorganic fillers such as silica powder and antimony trioxide, which are generally used as flame retardants. As an epoxy resin composition for VLSI, it is essential that both of them generate less radiation.

Patents relating to the present invention include Japanese Patent Application Laid-Open No. 57-1951.
There is No. 51 publication. The gist of this is to use low-radiation silica powder as a filler, but the intended low-radiation characteristics cannot be obtained in applications requiring flame retardancy, that is, in compositions using flame retardants.

At present, a composition containing no flame retardant has almost no use and is extremely poor in industrial and industrial utility.

Moreover, when conventional antimony trioxide is used as a flame retardant, antimony trioxide is a substance that generates a large amount of radiation (α dose 0.3 to 0.8 CPH / cm ² , even if flame retardation can be achieved, epoxy resin composition It is not possible to obtain low radiation characteristics as a product.

<< Object of the Invention >> Therefore, in the present invention, as a result of researching to obtain an epoxy resin composition that imparts flame retardancy and satisfies low radiation, as a result of using an inorganic filler having extremely small radioactive impurities, The present invention has been completed by using antimony trioxide whose surface is coated with silica as a flame retardant.

<< Structure of Invention >> That is, the present invention relates to an epoxy resin containing (a) a filler having an α dose of 0.005 CPH / cm ² or less and (b) an antimony trioxide whose surface is coated with silica having a thickness of 5 μm or less. Is a low-radiation epoxy resin composition characterized by being compounded as a flame retardant.

Epoxy resin means all those having an epoxy group,
For example, pisphenol A type epoxy resin (shell 82
No. 1001, etc.), novolac type epoxy resins (Nippon Kayaku EPPN-201, Dainippon Inka Chemical Industry Epicron N-673 etc.) and the like.

As the curing agent, all that react with an epoxy resin are mentioned, for example, phenol novolacs (Nippon Kayaku PN-
80, OCN-100, etc., acid anhydrides (TCPA, H
HPA), amines (DDA, DDM) and the like.

Examples of the filler include silica, alumina, calcium carbonate, mica, clay, glass, asbestos, aluminum hydroxide and the like.

In particular, high-purity fused silica and high-purity alumina having the characteristics shown in the following table are useful for achieving the object of the present invention.

The silica-coated antimony trioxide used as the flame retardant must have a thickness of 5 μm or less. If the thickness is more than this, the effect of antimony trioxide as a flame retardant is lost.

Finally, in the use of molding materials for semiconductor encapsulation, it is preferable to use 50 to 90% by weight of fused silica among inorganic fillers as a filler and 1 to 10% by weight of silica-coated antimony trioxide as a flame retardant. In addition, as an epoxy resin, an ortho-cresol novolac type epoxy resin, especially a softening point of 80 ° C. or less, an epoxy equivalent of 220 or less, a total chlorine amount of 1000 ppm or less, and an electric conductivity of pressure cooker extract water of 500 μ / cm or less. As the curing agent, phenol novolac, particularly a softening point of 105 ° C. or less, an electric conductivity of pressure cooker extraction water of 100 μ / cm or less, and an amount of formic acid of 50 ppm or less are preferable.

(Note) Total chlorine amount: measured by the sodium amalgam method Pressure cooker extraction conditions = 5 g of resin and 4 parts of distilled water
Extraction at 0 g for 180 hours at 180 ° C. << Effects of the Invention >> The present invention provides an epoxy resin composition containing extremely few radioactive impurities as described above, and a super LSI encapsulated with the low radiation epoxy resin composition of the present invention. Has a feature that the soft error due to radiation is extremely smaller than the conventional one. That is, it is to further promote the plasticization of the VLSI, and the effect of contributing to the generalization of the VLSI is extremely great.

<Example> Hereinafter, a description will be given using an example of study on a low-pressure encapsulating molding material.

The raw materials used in Examples and Comparative Examples are as follows. or,
All parts in the formulation are parts by weight.

Examples 1-2 and Comparative Examples 3-5 Holtocresol novolac type epoxy resin (Sumitomo Chemical ESCN-195XL) 20 parts, phenol novolac (Nippon Kayaku PN-100) 10 parts, fused silica 70 parts, flame retardant epoxy (Nippon Kayaku BREN) 3 parts, 1 μm thick silica-coated antimony trioxide a part, 5 μm thick silica-coated antimony trioxide b part, 10 μm thick silica-coated antimony trioxide c part, antimony trioxide (Sumitomo Metal Mining) d part, silane coupling agent (Chisso EES-M) 0.5 part, catalyst (Kai Kasei PP-360) 0.5 part, carbon (Mitsubishi Kasei) 0.5 part, release agent (Noda wax) 0.5 part, 100 ° C A heating roll was mixed for 3 minutes to make a trial molding material. At this time, the types of fused silica and flame retardant were set to the levels, and several types of molding materials were obtained as shown in Table 1. As a result of investigating the characteristics and soft error rate of these molding materials, as shown in Table 1, it is indispensable to use, as a molding material for VLSI, both a filler and a flame retardant with less radioactive impurities. I knew that.

Radioactive impurity amount: Measured by neutron activation analysis α dose: Measured by α ray counter (Science Spectrum) Soft error rate: Unit (% / 1000device.hr)

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Claims (1)

[Claims] 1. An epoxy resin is blended with (a) a filler having a radioactive dose of 0.005 CPH / cm ² or less at an α dose, and (b) antimony trioxide whose surface is coated with silica having a thickness of 5 μm or less as a flame retardant. And a low radiation epoxy resin composition.