High-performance packaging technology for very-high-speed ATM switching systems

This paper describes high-performance, high-density multichip modules (MCMs) using a copper polymide multi-layer substrate and innovative heat-pipe cooling for high-speed ATM switching systems. High-speed ATM link wires are interconnected on the top surface of the MCMs by the newly developed flexible printed circuit cables and con-nectors to reduce the rear-side I/O count and achieve 620-Mbit/s 32-bit parallel interconnections. A heat-pipe is attached to the back surface of each MCM to cool the power dissipation, which is 30 W per MCM. With a 2-m/s forced air flow, a prototype ATM switch system operated at 320 Gbit/s (with 8 × 8 MCMs) with a maximum junction temperature of less than 85 °C. These results indicate that this technology is suitable for future B-ISDN high-speed switching systems.