Optical emission during the plasma etch for process control of the litho-etch bias

摘要

In this work we present the suitability of using the optical emission spectroscopy (OES) as real-time monitoring of the reactive ion etching (RIE) process. Selecting the proper wavelength (520nm), we found that the OES monitoring is more reliable than the typical etch rate statistical process control (SPC). In this paper we discuss our experience of using in-situ and ex-situ SPC’s to monitor the SiOC (hard mask) etching and trimming.