Advanced interconnect and low cost /spl mu/ stud BGA

Abstract

The /spl mu/ stud BGA is designed to reduce the number of interconnects for higher reliability and low cost. The manufacturing processes of conventional lead-frame are applied to make a high pin count package. Numerous studs are laid out around the LSI's pad area in 0.5 mm pitch for wire bonding. The bottoms of the studs are directly connected to the substrate by micro-soldering. The /spl mu/ stud BGA has no routine in the encapsulated package body. Only bonding wires and studs are used for interconnection. Because of this, the package style is simpler and smaller than other kinds of high density package. It is a shrunken lead-frame style package. The lead-frame with numerous studs is manufactured by a conventional photochemical etching and electroplating process. The package is molded by a plastic transfer molding machine.