The specification describes a high density I/O IC package in which the IC chip is bonded to a silicon intermediate interconnection substrate (IIS), and the IIS is wire bonded to a printed wiring board. This marriage of wire bond technology with high density I/O IC chips results in a low cost, high reliability,...http://www.google.com/patents/US6282100?utm_source=gb-gplus-sharePatent US6282100 - Low cost ball grid array package
