Patent ID: 7056978

Claim:
A no-flow underfill encapsulant material comprising: a) one or more epoxy resins; b) one or more linear polyanhydride comprising particles that are equal to or smaller than 50 microns; c) one or more catalysts, and d) one or more core shell polymers, and e) a cyclic anhydride, wherein the epoxy resin is selected from the group consisting of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, vinylcyclohexene dioxide, 3,4-epoxy-6-methyl cyclohexyl methyl-3,4 -epoxycyclohexane carboxylate, dicyclopentadiene dioxide, bisphenol A resin, 2,2-bis( 4-hydroxyphenyl) propane-epichlorohydrin copolymer, bisphenol F resin, epoxy novolac resin, poly(phenyl glycidyl ether)-co-formaldehyde, type epoxy resin, dicyclopentadiene-phenol epoxy resins, naphthalene epoxy resins, epoxy functional butadiene acrylonitrile copolymers, epoxy functional polydimethyl siloxane, and mixtures thereof and wherein the cyclic anhydride is a cycloaliphatic anhydride selected from the group consisting of methylhexa-hydro phthalic anhydride methyltetra-hydrophthalic anhydride, nadic methyl anhydride, hexa-hydro phthalic anhydride, tetra-hydro phthalic anhydride, dodecenylsuccinic anhydride, phthalic anhydride and mixtures thereof and comprises up to about 30 wt % of the encapsulant.