The Effects of Epoxy Encapsulant Composition on Semiconductor Device Stability

This paper describes the effects of various ingredients in an epoxy resin formulation on the electrical stability of encapsulated transistors with only thermal oxide passivation. The type and level of ionic impurities and/or polar contaminants in a completely formulated epoxy resin, which affect the electrical characteristics of transistors, are discussed with specific reference to the nature of the epoxy, hardener, promoter, filler, and other ingredients used. Although the study was directed toward the development of improved epoxy resins for semiconductor applications, the principles involvedare applicable to other organic or inorganic dielectric materials.