SEMICONDUCTOR DIE-ATTACH TECHNIQUE AND COMPOSITION THEREFOR

摘要

A method of attaching semiconductor die to a package substrate and a composition for such die attach is disclosed, which method and composition comprise the combination of a low and a high-melting powder with a vehicle consisting of a solvent and a binder so as to form a thick-film ink. The ink is deposited onto the package substrate and the semiconductor die with a metallized back surface is located in contact with the deposited ink. The package containing the ink and the die is heated to a temperature of approximately 160 DEG C. so as to remove the solvent from the powders and the residual binder. Next, the package is fired at a temperature within the range of approximately 200 DEG C. to 430 DEG C. so as to melt the low-melting powder which bonds the chip to the package substrate. Then, a lid is sealed over the die-receiving cavity of the package by heating the package and the bonded die to a temperature within a range of approximately 400 DEG C. to 450 DEG C. wherein the low-melting powder remelts and the high-melting powder partially dissolves into the liquid of the remelted low-melting powder.