Thermocompression bonding methods and buffer layers therefor

Abstract

Processes for bonding substrates together. Such a process includes mating a copper film on a first substrate with copper pillars on a second substrate so that a surface of the copper film contacts surfaces of the copper pillars and so that a buffer layer is between the surface of the copper film and the surfaces of the copper pillars. The buffer layer is cobalt or nickel. The copper film is thermocompression bonded to the copper pillars at a bonding temperature while the first and second substrates are subjected to compression that presses the copper film and the copper pillars together at a bonding pressure.

Dependencies are inferred from the claim text.