Solvent-free epoxy based adhesives for semiconductor chip attachment and

Abstract

The present invention discloses chip (die) bond adhesive formulations preferably comprising a siloxane containing epoxide preferably a diglycidyl ether derivative, an anhydride curing additive which is soluble in the epoxide without the use of a solvent, and, optionally comprising, and oligomeric/polymeric co-additive of the type poly(alkylacrylate or -methacrylate), in conjunction with thermal and electrically conductive fillers and conventional co-catalysts used for curing epoxy systems to provide reworkable epoxy adhesives. Also disclosed are adhesive formulations comprising a siloxane containing epoxide and a hydroxybenzophenone curing additive which is soluble in the epoxide without the use of a solvent. The chips can be bonded to the substrate by conventional heating and curing techniques. With epoxy adhesive compositions comprising polyacrylate additives, the die bonded assembly can be reworked by heating the assembly to about 180.degree. C. to 250.degree. C. removing the chip, and rebonding a new chip on the same surface without any effect on the shear strength for die bonded on to gold, copper, silver or a ceramic die pad. Die shear strength using the adhesives remains unchanged when exposed to thermal shock involving -65.degree. C. to +150.degree. C. excursions, and HAST test at 130.degree. C. /85 percent RH (Relative Humidity) or 85.degree. C./85% RH. A method is also provided for using the adhesives to make electronic component assemblies.