Patent ID: 7560519
Filing Date: 2009-07-14
Classification: C08F,C08K,C08L,H01L,Y10T

Abstract:
1. A liquid, 100% solids, non-self fluxing, one-part underfill composition, consisting essentially of: from 5% to 30% by weight of a photocurable component containing no acidic groups, said photocurable component comprising one or more ethylenically mono-unsaturated monomers having at least 6 carbon atoms, oligomers thereof, or combinations thereof, from 10% to 45% by weight of a polyfunctional epoxy resin, from 0.3% to 3% by weight of at least one photoinitiator, from 40%-70% by weight of a non-electrically conductive filler, from 1%-3% by weight of a nonfluxing latent thermal accelerator, said underfill in the thermoset state exhibiting a flexural modulus of from 1000 to 5000 MPa at 20° C., and a coefficient of thermal expansion below its glass transition temperature of from 15 to 50 ppm/° C.