Multilevel statistical process control of asynchronous multi-stream processes in semiconductor manufacturing

In semiconductor manufacturing, the purpose of chamber matching is the alignment of process and yield results of distinct chambers performing in parallel the same process step on different silicon wafers. In this paper, multi-level linear models and statistical process control techniques are jointly employed to define control charts for monitoring chamber matching accuracy and preemptively report chamber misalignments. Specifically, multilevel versions of the classic T² Control Chart, MEWMA Control Chart and Self-Starting Control Chart are defined and tested against experimental and simulated data.