Computer Experiments for Quality Control by Parameter Design

Taguchi's off-line quality control methods for product and process improvement emphasize experiments to design quality “into” products and processes. In Very Large Scale Integrated (VLSI) circuit design, the application of interest here, computer modeling is invariably quicker and cheaper than physical experimentation. Our approach models quality characteristics generated by the computer simulation as functions of both the engineering and noise parameters. This single experimental design for both types of parameters typically requires far fewer runs. The model is used to predict the quality characteristics, from which loss statistics can also be predicted and optimized. In the VLSI applications described, we obtain effective prediction of product performance with comparatively few observations.