Subject: Re: Problem wbsilicide SNF 2008-04-26 15:00:56: wafer lost drainage did not work
From: shott@snf.stanford.edu
Date: Sun, 27 Apr 2008 10:14:47 -0700

Markus:
I've extracted your wafers from the hot pot at wbsilicide.  As they were in the cassette
labeled Gold Contaminated and there was an empty teflon cassette in the dump rinser
also labeled Gold Contaminated, I placed your wafers in that cassette and have left
them sitting in water in the dump rinser.  I did not want to do anything to try to dry
them.
While I'm still looking around, the aspirator seemed to work for me to allow me to drain
the sulfuric/peroxide from the hot pot.  Although I cannot tell what the temperature
is, there is an interlock on the aspirator that prevents the aspirator from turning
on if the acid in the hot pot is too hot.  Was the hot pot at something close to 120
degrees C when you tried to empty it?  If so, this is likely why it would not drain
for you.  I think that the maximum temperature at which the acid can be drained with
an aspirator is either 50 or 80 degrees C ....
In any event, your wafers are sitting in water in a cassette in the dump rinser at wbsilicide.
Happy processing,
John