In situ cleaning of a chamber wall divided in a reactive ECR plasma

Basic properties of in situ cleaning of a chamber wall divided in a reactive electron cyclotron resonance (ECR) plasma have been investigated by monitoring ion current flowing into a three-segmented side wall, to which radio-frequency (rf) surface voltage is applied externally. To keep the wall condition clean during the plasma processing, we have found that the positive sheath voltage toward the wall surface is an important factor as well as the wall temperature. The method of the chamber wall cleaning proposed here is quite useful for keeping the initial wall condition and plasma processing parameters without degrading the quality of the processing.