ABSTRACT
Genichi Taguchi’s basic approach is that the design must be made robust — that is, able to be produced to good quality despite the variables inevitable in the manufacturing process. The American Supplier Institute has gone so far as to develop training techniques in Taguchi methodology and register “Taguchi Methods” as trade and service marks. Equally important are the variables in manufacture, such as moisture and dust that can lead to defects being produced. Taguchi set out to improve the productivity and quality of design to turn quality into an inherent factor of a product rather than a discipline added at the manufacturing stage. In the US semiconductor industry, Taguchi’s methodology has been adopted to optimize many aspects of the process, including growth of epitaxial layers, plasma etching, and the forming of small windows in integrated circuits. Quite different was the problem encountered at the Cadillac assembly plant, both in terms of its type and what the Taguchi tests showed.
