Active Silicon Substrate Multi-Chip Module Technology for Sensor Signal Processing and Control

A new approach to build multi-chip modules (MCMs) using active silicon substrate (ASIS) technology is being developed by Lockheed for future sensor signal processing and control applications. The ASIS MCM inherently offers a functional platform versus other approaches using a passive nonfunctional substrate. The Lockheed ASIS design uses benzocyclobutene (BCB) for a low dielectric and copper for interconnect over an active substrate. Support chips are attached to the interconnect over the substrate by solder bumps. This provides a versatile manufacturing concept for easy rework. Bare die testing and bum-in of support chips should eliminate most rework. The result is a dense, high performance, three-dimensional MCM of closely placed functional elements. Unique architectures are possible with optimized active substrates and support chips, but this approach also allows MCMs to be developed sooner with standard integrated circuits.