Optical emission procedure and device for the final point detection of plasma etching processes

摘要

The device monitors the optical emission intensity of the plasma in a narrow band centred about a predetermined spectral line. It generates a first signal indicative of the spectral intensity of the etch product series. The device further monitors the optical emission intensity of the plasma in a wide band and generates a second signal indicative of the spectral intensity of the continuum plasma emission. The device further monitors the magnitudes of the first and second signals and generates a termination signal when the magnitudes diverge.