ABSTRACT

The number of components that can be reliably fabricated on a chip is limited by the fabrication process. Wafer scale integration (WSI) was proposed in the 1980’s and received a lot of enthusiasm initially. WSI intends to create and connect all chips in a system on the same wafer. Unfortunately, the yield of a fabrication process is inversely proportional to the chip area. It was soon clear that the low yield of WSI limited its practical applications. The WSI concept has been replaced by the multi-chip module (MCM) technology. The MCM approach overcomes the packaging limits of printed circuit boards by eliminating chip packages. Chips are mounted directly on a silicon wafer with layers of metal interconnections. A single Very Large Scale Integration structure may contain hundreds or thousands of cells connected in a more/less near-neighbor array structure. The direct reconfiguration scheme will fail if there is more than one horizontal fault in any row of the array.