Recent developments in silicon hybrid multi-chip modules

The author describes the Research Initiative Silicon Hybrids (RISH) programme, established in September, 1986, to investigate all aspects of silicon in multichip module applications. A series of test vehicles has been fabricated to demonstrate the merits for real circuit applications. The author summarizes the merits of silicon as a multichip module substrate and considers, in detail, the specific application of an active substrate multichip module in which some of the circuitry is fabricated within the substrate. Within the programme extensive use has been made of flip-chip technology. The close expansion match between a silicon substrate and a silicon chip would be expected to lead to very good reliability when a flip-chip process is used. Initial results confirm these expectations