In-situ measurement of wafer position on lower electrode

摘要

A method and apparatus for measuring a wafer position on a lower electrode in a plasma etching device are disclosed herein. A wafer is generally placed on a lower electrode in a process chamber of a plasma etching device. Such a wafer (i.e., semiconductor wafer) generally comprises a front side and a back side. A differential pressure gradient between the front side and the back side of the wafer is determined, and thereafter, a position of the wafer on the lower electrode can be measured utilizing the differential pressure gradient.