Abstract: A radiation-sensitive resin composition comprising:(a) an epoxy group-containing alkali-soluble resin, or a combination of an alkali-soluble resin which may have an epoxy group and an epoxy compound,(b) 1,2-naphthoquinonediazide sulfonic acid ester, and(c) a solvent.The above radiation-sensitive resin composition is useful as a material for forming a lens.

Abstract: A novel raddery organopolysilsesquioxane having lower alkyl groups and alkenyl groups as the side chains and, if necessary, having aryl groups and/or hydrogen atoms bonded as the side chains can be produced by adding water to a solution of a lower-alkyltrihalogenosilane, an alkenyltrihalogenosilane, and, if necessary, an aryltrihalogenosilane and/or a trihalogenosilane in an organic solvent, and heating the resulting mixture. The aforesaid organopolysilsesquioxane can be used for forming a patterned surface-protecting layer or insulating layer for a semiconductor device, in the form of a mixture with a compound which generates crosslinking-reaction-active species upon irradiation with light or an ionizing radiation.

Abstract: A laddery lower alkylpolysilsesquioxane represented by the formula: ##STR1## wherein R and R' represent same or different lower alkyl groups, and n represents an average degree of polymerization, said laddery lower alkylpolysilsesquioxane having a heat-resistant thin film-formability, characterized in that 15 to 30% by weight of the lower alkylpolysilsesquioxane is occupied by the portion having a standard polystyrene-reduced molecular weight of 20,000 or less as measured by gel permeation chromatography. Said silicone resin in which R and R' are methyl is prepared by dissolving CH.sub.3 SiCl.sub.3 in a ketone or an ether, adding water to this solution with stirring to hydrolyze CH.sub.3 SiCl.sub.3, condensing the hydrolyzate and, if necessary, subjecting the resulting condensate to a treatment for adjusting the proportion of the low molecular weight portion in the product.