Etch end point detector using gas flow changes

摘要

As etching progresses from one layer of material to another in reactive ion etching systems, the partial pressures of the reaction chamber gas components change. In constant pressure reactive ion etching systems, changes in chamber pressure are corrected by changes in the etchant species flow rate into the reaction chamber. By monitoring flow rate, information is obtained which may be used to identify the points where partial pressures change, and latter may, in turn, be used to derive etching points in the material being etched.