Restructurable VLSI program

The main objective of the Lincoln Restructurable Very Large Scale Integration (RVLSI) Program is to develop methodologies for designing whole-wafer-scale systems with complexities approaching a million gates. In our approach, we envisage a modular style of architecture comprising an array of cells embedded in a regular interconnection matrix. Ideally, the cells should consist of only a few basic types. The interconnect matrix is a fixed pattern of metal lines augmented by a complement of programmable switches or links. Conceptually, the links could be either volatile or nonvolatile. They could be of an electronic nature such as a transistor switch, or could be permanently programmed through some mechanism such as a laser. The present main thrust of the current RVLSI Program is toward laser-formed interconnect. The link concept offers the potential for a highly flexible, restructurable type of interconnect technology which could be exploited in a variety of ways. For example, logical cells or subsystems found to be faulty at wafer probe time could be permanently excised from the rest of the wafer. The flexible interconnect could also be used to 'jump around' faulty logic and tie in redundant cells judiciously scattered around the wafer for this purpose. Also, the interconnect could be tailored to a specific application in order to minimize electrical degradations and performance penalties caused by unused wiring.