Dear Andrew, 1. Process a full batch of several wafers. Some will be used for development of your RIE step. 2. RIE step: adjust your process conditions with some of the wafers from your batch. Keep in mind that you need the depth tolerance since, due to chamber and plasma geometry, acceleretaing plates geometry... the depth will be different at the centerand at the edges of your wafers. 3. Proceed with the rest of your process Keep in mind that if you want your process to be reproducible, all of your conditions must remain the same. In other words, if you are etching silicon, don't forget that Si oxidation is time dependant, beware of the contamination of your tools, etc. Ed On Thu, Sep 2, 2010 at 3:30 AM, 杜 彦召wrote: > Hi all: > > Does anyone know how to control the RIE etch depth given no etch stop > layer? > > > Andrew