Patent ID: 8157158

Claim:
A method for forming a solder joint on a solder capture pad of a substrate having a circuit, comprising: applying to said capture pad a lead free solder, the lead free solder being selected from the group consisting of Sn—Ag—Cu solder, Sn—Cu solder and Sn—Ag solder; and adhering said solder to said solder capture pad by melting and cooling said solder; said solder containing between 0.1 and 6.0 percent by weight Zn, so that formation of voids at an interface between said solder and said solder capture pad is suppressed; Zn content of said solder being determined in accordance with a ratio of volume of said solder to surface area of said solder capture pad; wherein the solder capture pad is comprised of plated Cu, further comprising annealing of the plated Cu pad at a temperature of approximately 550° C., prior to forming the solder joint.