Comparison study between optical emission spectroscopy and x-ray photoelectron spectroscopy techniques during process etch plasma

摘要

This paper describes the complementary study of plasma-emission wavelength by optical emission spectroscopy (OES) and the experimental results collected from an x-ray photoelectron spectroscopy (XPS) directly over the etched wafer. We have monitored two kinds of etch processes, where the chemistry used was based on CF4, He, CH2F2, and HBr, O2. Additionally, the study was carried out across a typical silicon wafer and across a silicon wafer with a coating layer of hydrogenated amorphous carbon (a-C:H) which is used in semiconductor manufacturing as a mask layer to etch very small dimensions. The study done by OES along with XPS analysis was compared in order to propose a mechanism of formation of the radical during the plasma etching processes.