Patent ID: 7498197

Claim:
A method of making an electronic circuit assembly comprising: providing a substrate having a pattern of electrical conductors; depositing a curable resin composition on a surface of the substrate, the curable resin composition comprising about 10% to about 40% by weight, based on the total weight of the curable resin composition, of surface functionalized nanoscopic silica particles having a particle size distribution of about 1 nanometer to about 200 nanometers dispersed in a thermosettable resin comprising a polyepoxide having the formula X—((CH 2 ) m —(N)—((CH 2 ) n -(Z)) 2 ) p , wherein X is an aromatic ring or a cycloaliphatic ring, m is 0 or a positive integer, n is a positive integer, Z is an epoxy group, and p is 2, and further comprising a polyamine cross-linking agent having at least one of from 2 to 4 primary amine groups, an imidazole cross-linking agent, or a combination thereof and wherein the surface functionalized nanoscopic silica particles are functionalized with a silane compound, a silazane compound, or a combination thereof; positioning an electronic component having solder bumps on the substrate, so that the solder bumps are in registry with a corresponding pattern of bond pads on the substrate and so that the curable resin composition is disposed between and substantially fills an interstitial space between the substrate and the electronic component; reflowing the solder bumps to make electrical connections between the electronic component and the pattern of electrical conductors on the substrate; and curing the curable resin composition to produce a cured resin composition concurrently or subsequently to reflowing the solder bumps, wherein the cured resin composition has a modulus of about 1 to about 3 gigapascals at 150° C.