Systematic applications of multivariate analysis to monitoring of equipment health in semiconductor manufacturing

In this work, a systematic procedure of building a model for monitoring batch processes in semiconductor manufacturing and visualization of monitoring results will be presented. Semiconductor manufacturing batch-processing stages usually consist of many steps. Aging trends likely to be detected only in the steady state period of each step. Large fluctuations can be found in on-off period of each step. Hence ¿step-trend¿ variables, i.e. mean shifts from reference profiles of each steps, are defined to track aging trends. Residuals from this shifted profile are then used to provide a combined health index of each batch through Hotelling T2 analysis.