Problem stsetch 2001-07-15 04:58:49: Hazy scum on wafers

[mbartsch at snf.stanford.edu]

Running the SMOODEEP program on relatively short etches (<20um), I've been getting some sort of non-uniform residue deposited on my wafers.  I did not have this problem running the same program a week ago, so it must be a new development.  The scum seems to be completely resistant to oxygen plasma...I haven't checked yet to see if anything else will remove it...of course I also don't know what may now be contaminating my wafers...  I ran a 30min O2 clean of the STS chamber, but the next wafer I ran still came out with scum on it.