APPLICATION OF STATISTICAL DESIGN AND RESPONSE-SURFACE METHODS TO COMPUTER-AIDED VLSI DEVICE DESIGN

A statistically oriented methodology for optimization and sensitivity analysis of VLSI process, device, and circuit design through computer simulation has been developed. Emphasis has been placed on maintaining a clear distinction between design synthesis and design analysis. Design analysis is viewed as a multiple input-output system resulting in a multiple-constraints-optimization problem. It is shown how simple graphic techniques or rigorous mathematical optimization can be performed within a constrained desirability space to determine optimal operating conditions. This leads directly to the concept of global input factors, which affect a large number of the response variables, and specific input factors, which can be used to adjust the operating level of a small number of response variables. By using the derived empirical equations to desensitize the responses to variations in input factors, the proposed methodology can play a key role in designing for manufacturability. As proof of concept, the methodology has been applied to the optimization of a VLSI BIMOS technology, with satisfactory results.