US Patent 8115310 Copper pillar bonding for fine pitch flip chip devices

A semiconductor device assembly can include a semiconductor chip, a receiving substrate, and a spacer structure interposed between the semiconductor chip and the receiving substrate. The spacer provides an unoccupied space between a pillar and a bond finger for excess conductive material, which can otherwise flow from between the pillar and bond finger and result in a conductive short. The spacer can also provide an offset between the pillar and bond finger.