Optoelectronic multichip module packaging technologies and optical input/output interface chip-level packages for the next generation of hardware systems

Optical interface multichip module (MCMs) and optical interface ball grid array (BGA) packages promise to overcome the bottleneck of electrical interconnection. This will lead to telecommunications systems that have throughput exceeding several terabits per second and computer systems having speeds of several gigahertz. A national project has resulted in the development of over-100-Gb/s optoelectronic MCM (OE-MCM) packaging technologies, which will play a key role in the construction of terabits per second hardware systems. The packaging technologies feature a 10-cm square OE integrated substrate containing low-loss optical waveguides and filled vias formed by laser drilling and electroplating for improved heat dissipation, which allow higher device densities. Reliable and stable flip-chip device packaging has also been developed. This packaging features accurate photonic device bonding by microsolder bumps, low loss optical coupling using reflection mirrors, and an optical underfill technique to reduce optical reflection noise. Optical interface BGA packages using microlenses for optical input or output terminals allow high-density board packaging because of the fiberless optical interface and wide misalignment tolerances of +-100 (mu)m, which is compatible with current electronic assembly techniques. It is expected that the BGA packages will be widely developed for high-density low-cost packaging on boards.