STRIP-PLOT DESIGN FOR 2-STEP PROCESSES

Conducting experiments across processing steps is important when it is desired to study the interactions among factors where some factors ar e from one step and the other factors are from the other step. The str ip-plot design is a very efficient design, both on resources required and time needed, for studying multiple-step processes. This paper desc ribes the construction and analysis of the strip-plot and split-plot d esigns. A case study is described where an experiment was run to impro ve the quality of separation by implantation of oxygen silicon on insu lator wafers while reducing costs. In this study the levels of one set of factors are not replicated; thus the half-normal probability plot is used to extract information so that a mixed model can be used to pr ovide estimates of the parameters of the corresponding response surfac e model. (C)1998 John Wiley & Sons, Ltd.