In situ observation of etching profile in inductively coupled plasma etching of GaAs and InP using long distance microscope

We investigated the in situ observation of the etching profile in inductively coupled plasma etching of GaAs and InP, which enables real-time control of the etching profile and depth from outside the process chamber. The etching profile image of the line and space was obtained with a long-distance microscope. The image was almost the same as that obtained with a scanning electron microscope or a conventional optical microscope. We think that this proposed method is an important monitoring technique for real-time control in the dry etching process.