I have been etching wafers with XeF2 and usually get great results but recently
have noticed that randomly it seems that the etch process goes out of control.
Four wafers were processed on Thursday with veru good results and then another
batch was run on Monday and the etch was very uneven and created a very rough
surface in certain areas while not etching others at all. Has anyone have a
similar experience? Any ideas on what makes the variation from day to day so
different?
DT