Patent ID: 7022410

Claim:
An underfill composition comprising: a first curable transparent resin composition comprising an aromatic epoxy resin in combination with a solvent, a functionalized colloidal silica dispersion, and at least one other component selected from the group consisting of cycloaliphatic epoxy monomers, aliphatic epoxy monomers, hydroxy aromatic compounds and combinations and mixtures thereof; and a second curable fluxing composition comprising at least one epoxy resin, wherein the second curable fluxing composition further comprises at least one epoxy hardener, and wherein the at least one epoxy hardener comprises a difunctional siloxane anhydride of the formula: where X is from 0 to 50 inclusive, and each R′ and R″ are independently selected from the group consisting of C 1-22 alkyl, C 1-22 alkoxy, C 2-22 alkenyl, C 6-14 aryl, C 6-22 alkyl-substituted aryl, and C 6-22 arylalkyl.