Epoxy resin composition for encapsulating semiconductor

Claim 1

An epoxy resin composition for encapsulating a semiconductor comprising: (a) an epoxy resin; (b) a phenol resin; (c) a phenol-modified silicon-containing compound obtained by reacting an organic silicone compound selected from the group consisting of a first organic silicone compound having an epoxy equivalent of from 500 to 20,000 and a molecular weight of from 2,000 to 200,000 represented by the following formulae (1-a) and (1-b), a second organic silicone compond having an epoxy equivalent of from 500 to 20,000 annd a molecular weight of from 2,000 to 200,000 represented by the following formula (2), and mixtures of said first and second organic silicone compounds, with from 0.2 to 10 molar equivalents of an organic silicon compound represented by the following formula (3) per molar equivalent of the epoxy group of the compound of the formulae (1-a), (1-b) and (2) and with a phenol resin; ##STR12## wherein in the formulae (1-a), (1-b) and (2) R 1 stands for a hydrogen atom, a methyl group, an ethyl group or a phenyl group, R2 for an alkylene group having 1 to 5 carbon atoms, X for an organic group containing an epoxy group, Y is a polyoxyalkylene group having a polymerization degree of from 5 to 500 and stands for a polyoxyethylene group, a polyoxypropylene group and a copolymer group thereof, and l, m, n, o and p each represents an integer; and wherein the formula (3) Z is a functional group reactable with an epoxy group and stands for a mercapto group, an amino group or a ureido group, R 3 for an alkylene group having 2 to 5 carbon atoms, R 4 for a methyl group or an ethyl group and q is 0, 1 or 2; and (d) an inorganic filler, wherein 5 to 50 parts by weight of (c) is present for each 100 parts by weight of (a).