particle count update

Sharleen Beckwith beckwith at snf.stanford.edu
Tue May 8 13:50:07 PDT 2001


Early this afternoon I put 10 spankin' new wafers through program 25 (etch
time = 60 sec/wf.) None of the wafers had any particles on them prior to
going through the lam.

After the lam etch, the best wafer had no particles, the second best wafer
had one particle, the worst wafer had 6 particles. The rest of the wafers
had between 2 and 4 particles each. There was no pattern, as far as
placement in the cassette is concerned; or looking at it from a time
perspective, it didn't matter if the wafers went through the etch first
or last; the best and worst wafers were randomly found in the cassette.




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