Semiconductor device-encapsulating epoxy resin composition containing secondary amino functional coupling agents

A semiconductor-encapsulating epoxy resin composition comprising:

• (A) an epoxy resin having at least two epoxy groups,
• (B) a curing agent selected from at least one member of the group consisting of a phenol-novolak resin, a cresol-novolak resin, a novolak resin represented by the following formula:
• ##STR7## wherein n is zero or an integer of at least 1, a novolak resin synthesized from bisphenol A or resorcinol, and polyhydric phenol compounds, and
• (C) fused silica which comprises 40 to 90% by weight of crushed fused silica having an average particle diameter not larger than 12 .mu.m and 10 to 60% by weight of spherical fused silica having an average particle diameter not larger than 40 .mu.m said percentages being based on the total of crushed and spherical fused silica, and said average particle diameter being defined as the median particle diameter at which the cumulative weight is 50 percent, and which has been surface-treated with a silane coupling agent having an amino group which is a secondary amino group, or having amino groups, wherein said amino group or amino groups are all secondary amino groups;
• said epoxy resin being present in an amount of from 3 to 30% by weight of said composition, and said fused silica being present in an amount of from 70 to 95% by weight of said composition.