Nonplanar VLSI arrays with high fault-tolerance capabilities

VLSI architectures for improved fault tolerance are proposed and analyzed. The architectures include structures with two planar layers of processing elements as well as extended cubic designs. The analyses for arrays with various redundancy levels show remarkable improvement in both array yield and processor use over those exhibited conventional two-dimensional structures. This improvement can be attributed to the benefits of the third dimension to increase the flexibility in spares allocation. The architectures can readily substitute arrays based on mesh or four-nearest-neighbor interconnections. From the fault-tolerance viewpoint the cubic structures offer no appreciable performance improvement over the simpler two-layer structures