New and simple optical method for in situ etch rate determination and endpoint detection

Optical emission spectroscopy has been established as a simple method for simultaneous etch rate determination and endpoint detection in ion beam etching. During the sputtering of a thin layer with a refractive index different from the substrate interference is detected in the reflected light emitted by excited beam particles. This method will be very useful for other plasma and beam-assisted processes too, like deposition, reactive ion etching, and reactive ion beam etching. In contrast to the conventional methods, no additional light source is required.