Epoxy resin compositions are disclosed which comprise (A) at least one
cycloaliphatic epoxy resin, (B) a curing agent comprising
hexahydro-4-methylphthalic anhydride, (C) at least one a boron containing
catalyst that is essentially free of halogen, and (D) at least one cure
modifier. The encapsulant (11) may also optionally comprise at least one
of ancillary curing catalysts, thermal stabilizers, UV stabilizers,
coupling agents, or refractive index modifiers. Also disclosed are
packaged solid state devices comprising a package, a chip (4), and an
encapsulant (11) comprising an epoxy resin composition of the invention. A
method of encapsulating a solid state device is also provided.
