From beckwith at snf.stanford.edu Tue May 8 13:50:07 2001 From: beckwith at snf.stanford.edu (Sharleen Beckwith) Date: Tue, 8 May 2001 13:50:07 -0700 (PDT) Subject: particle count update Message-ID: 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. From grupp at snow.stanford.edu Tue May 8 13:59:17 2001 From: grupp at snow.stanford.edu (Dan Grupp) Date: Tue, 8 May 2001 13:59:17 -0700 (PDT) Subject: particle count update In-Reply-To: Message-ID: Lest we forget the "N" in "SNF": BIG particles are just an indicator. Their visibility is an indicator that there are MANY SMALL PARTICLES on the wafer. Many can mean THOUSANDS. Yup, it's a problem... On Tue, 8 May 2001, Sharleen Beckwith wrote: > > 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. > > --------------------------------------------------------------------------- Dr. Daniel Grupp, Visiting Scholar Center for Integrated Systems Stanford University Stanford, CA 94305 (650) 724-6911 FAX: 723-4659 ---------------------------------------------------------------------------