Method to protect chamber wall from etching by endpoint plasma clean

摘要

A new method of controlling the level of cleaning of the etch chamber by measuring the light emission caused by particles within the plasma of the etch chamber. The etch chamber clean process is invoked as soon as the level of contaminants within the etch chamber is observed as being too high. This measuring of the contaminants within the etch chamber is performed by measuring the particle light emission. The etch chamber cleaning process is considered complete when the light intensity created by existing particles in the chamber drops by a certain percentage.