An ATM switch hardware technologies using multichip packaging

An asynchronous transfer mode (ATM) switching system constructed of copper-polyimide multilayer multichip modules (MCMs) is described. High throughput ATM switching systems require high-speed interconnections and high-density packaging to reduce the interconnection lengths. An ATM prototype switching system which consists of two ATM switch MCMs was developed. The ATM switch MCM contains 24 LSIs and a multilayer substrate with polyimide dielectric and a fine pattern copper conductor. A fine pitch flexible lead 680-way connector was developed to achieve a high-speed interconnection between the MCM and printed circuit board. Tap automated bonding (TAB) was used to allow pretesting of the LSI devices and to mount high pin count LSI devices onto the MCM. The system performed 16×16 ATM cell switching at 150 Mb/s. Furthermore, it transmitted NRZ signals of up to 810 Mb/s between MCMs via fine-pitch flexible lead connectors and a 40-cm line in the printed circuit board