Patent ID: 6015083
Filing Date: 2000-01-18
Classification: B23K,H01L

Abstract:
A process for applying solder bumps to a hard to solder substrate, comprising the steps of:melting a modified solder composition comprising a solder base alloy modified by alloying with a light reactive metal in an amount effective to wet and bond to a hard to solder pad surface, selected from the group consisting of aluminum, and aluminum alloy, and indium tin oxide, to make a solder interconnect on a microelectronic part;heating the surface of the pad;creating and maintaining an inert gas atmosphere over the pad;producing a microdrop of the modified solder composition within the inert gas atmosphere;applying the microdrop to the heated surface of the pad while maintaining the inert gas atmosphere; andfreezing the microdrop in electrical and mechanical contact with the surface of the pad.