Hitachi, Ltd.

Hitachi Chemical Company, Ltd.

Goro Tanaka

Hiroshi Suzuki

Toshikazu Narahara

Mikio Sato

Daisuke Makino

Akio Nishikawa

Yoshiaki Wakashima

Junji Mukai

Shinichi Toyoda

In a semiconductor memory device comprising semiconductor memory elements having such a degree of integration in memory circuits as to produce soft errors by incident .alpha.-rays derived from a packaging material and a package which packages the memory elements and is made from the packaging material, when an .alpha.-rays shielding layer made from a resinous material, which may contain one or more high-purity fillers, containing a total amount of 1 part per billion or less of uranium and thorium is interposed between the memory elements and the package, the generation of soft errors is reduced remarkably.

Semiconductor memories with .alpha. shield

Half-ester compounds obtained by reacting polycarboxylic acid anhydrides with aliphatic tertiary amino alcohols have excellent latent characteristics as a curing catalyst for epoxy resins which are normally catalyzed by tertiary amines. When epoxy resin compositions containing the half-ester compounds are applied to semiconductor devices, remarkably small leakage currents of the devices are observed.

Curing of epoxy resin systems using halfester compounds containing

Thermosetting resins are produced by blending 1 equivalent of a polyoxazolidone terminated by two vicinal epoxy groups and containing at least two oxazolidone rings with at least 1 equivalent of a polyfunctional isocyanate compound, adding 0.01 to 10% by weight of a catalyst which forms isocyanurate rings and oxazolidone rings based on the total amount of the polyoxazolidone and the isocyanate compound, and then heating the resulting composition to polymerize the composition by forming isocyanurate rings and oxazolidone rings. The resin compositions have excellent mechanical properties, and particularly excellent flexibility, and excellent thermal resistance.

Process for producing thermosetting resins

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Hitachi, Japan

Goro Tanaka