A Wide Area Vertical Expansion (WAVE/sup TM/) packaging process development

During the later 1990's, Tessera introduced a semiconductor packaging technology called WAVE (Wide Area Vertical Expansion) package to address the growing need for high pin count, high speed, high thermal dissipation, and high environmental reliability in advanced electronic packaging. The WAVE technology is an extension of Tessera's compliant packaging technologies that places a low modulus encapsulant between the silicon die and the package substrate to solve their CTE mismatch problem. The WAVE technology allows for compliant vertical interconnection links to be formed between the ICs and the substrate, with no need for a bond window. These interconnections are made simultaneously, in contrast to single point wire or lead bonding. The compliant interconnections and low modulus encapsulant enable the stress on BGA solder balls to be minimized. The WAVE package utilizes advanced materials and design to provide a unique combination of high electrical and thermal performance, high environmental reliability, and cost effective IC interconnection methodology. This paper presents one of the latest WAVE technology developments at Tessera.