An in situ monitoring method for PECVD process equipment condition

A key to successful consistent plasma processing is maintaining a consistent process chamber condition over a certain production period. To alleviate the concern, in situ process monitoring sensors are employed to investigate the plasma chamber conditions of both the deposition step with direct plasma and the cleaning step with a remote plasma system. In situ sensors are optical emission spectroscopy (OES), optical plasma monitoring sensors (OPMS), voltage current probes (VI-probes), and self-plasma OES (SP-OES). During the deposition, we perform the monitoring of a plasma condition associated with the applied RF power via OES, OPMS, and a VI-probe. In the chamber cleaning step using a remote plasma system does not allow plasma monitoring through the sidewall because the plasma is not formed in the process chamber, thus we employed SP-OES to monitor the by-product gas chemistry during the chamber cleaning process step. Successful monitoring results with some useful applications, such as arc detection, part failure detection, and cleaning process chemistry analysis, are presented in this paper. The use of in situ sensors with proper combination can help to understand the plasma process better, to achieve more precise control of plasma processing.