Patent ID: 6436730
Filing Date: 2002-08-20
Classification: H01L,H05K

Abstract:
A method for attaching an integrated circuit component to a substrate by solder bump interconnections, said substrate comprising a plurality of first bond pads, said integrated circuit component comprising a plurality of second bond pads formed of solder-wettable metal, said method comprisingforming a solder bump onto each second bond pad, said solder bump being formed of a lead-free solder alloy composed predominantly of tin and optionally up to 1.5 weight percent silver and containing between 2 and 8 weight percent copper, superposing the integrated circuit component onto the substrate to form an assembly such that each solder bump rests against a corresponding first bond pad, heating the assembly for a time and at a temperature effective to melt said lead-free solder alloy, whereupon each solder bump forms molten solder that wets the corresponding first bond pad, and cooling to solidify the solder to form solder bump interconnections bonding the first bond pads and the second bond pads.