VLSI design in the 3rd dimension

Recently, the need for increased circuit complexity has outpaced our ability to perform efficient routing and placement, while still maintaining small die sizes. Part of this problem can be attributed to the limits imposed by designing in two dimensions. Three-dimensional VLSI circuits, obtainable through using a transferred thin-film process, can provide a path for realizing complete structures, while reducing route lengths and die sizes. In this paper we report on our new three-dimensional design technology, devices which we have fabricated, and our move to an automated 3-D design path using Cadence and Synopsys design tools. We present both discussion of functional 3-D devices, and on-going work on VLSI design tools and the implementation of a 3-D microprocessor.