Musical wet benches (wbdiff down.)
mtang at stanford.edu
Sat Feb 23 22:13:41 PST 2008
Hi all --
Robin reports that the thermocouple in the sulfuric hot pot at wbdiff
appears blackened so that it may possibly have become contaminated.
(Please do not be alarmed if you used this station - there is a teflon
sheath around the TC which should prevent significant leaching -- and
subsequent HCl and HF dips should remove trace metals.) So, wbdiff is
shutdown until this TC can be replaced by Jim H or other maintenance
staffer and pot decontaminated.
While wbdiff is shutdown, Robin is starting decontamination procedures
on wbsilicide, so that it can be used for pre-diffusion cleans. This
will consist of pouring 5:1:1 H2O:HCl:H2O2 into the hot pots, HF tank,
and dump rinsers. She's generously agreed to start this -- whoever
needs this might need to finish it -- please check Coral for updated
Unfortunately, it appears that the wbsilicide spin rinse dryer is not
working (as per the last reported comment). If that is indeed, the
case, I'm afraid users will have to walk their wafers over to the wbdiff
spin dryer. (Inconvenient, I know, but just possibly better than the
alternative of jumping back and forth between acid dips.)
Moreover, I've also been informed that we're out of 50:1 HF. (Gee, no
end of fun!) Robin has kindly volunteered Eric to mix up a batch for
tonight, if needed. I'll come in the morning to stock up.
Again, apologies for the inconvenience -- Jim was out last week, but due
back Monday. I trust things will be straightened out then. And if
anyone has observations/suggestions/ideas about getting a handle on
weekend acid shortages (we ensure stocks are full Fridays at 4 pm -- are
there a lot of partial bottles? why don't acid change logs seem to
reflect shortages? help!) they would be much appreciated.
More information about the wbdiff