From duygu at stanford.edu  Sat Feb 23 17:27:43 2008
From: duygu at stanford.edu (Duygu Kuzum)
Date: Sat, 23 Feb 2008 17:27:43 -0800
Subject: 50:1 HF is needed
Message-ID: <20080223172743.qmzw8hv11c0sgssw@webmail.stanford.edu>

No more bottles are available. Please provide some as soon as possible.


From mtang at stanford.edu  Sat Feb 23 22:13:41 2008
From: mtang at stanford.edu (Mary Tang)
Date: Sat, 23 Feb 2008 22:13:41 -0800
Subject: Musical wet benches (wbdiff down.)
Message-ID: <47C10B15.3080404@stanford.edu>

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 
status reports.

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.

Thanks,

M


From shott at stanford.edu  Sun Feb 24 10:00:25 2008
From: shott at stanford.edu (John Shott)
Date: Sun, 24 Feb 2008 10:00:25 -0800
Subject: Update on wbsilicide status ....
Message-ID: <47C1B0B9.9050106@stanford.edu>

wbdiff and wbsilicide users:

First, I apologize to those of you who receive this twice, but since 
wbdiff activities are currently being done at wbsilicide, I felt that I 
should contact both lists.

This morning (Sunday at about 7 a.m.) the TraceTek leak detector sent in 
an alarm to work control that turned out to be a puddle underneath 
wbsilicide.  While I am not 100% certain, I currently believe that this 
is a small leak in the main drain line from that sink in a FuseSeal 
plumbing joint.  I've cleaned up the mess and now have both a nalgene 
tub and absorbent pads underneath the suspect area to catch/contain any 
additional leakage.

At this point, I see no reason to shutdown operations at this tool.  If 
anything, normal usage that results in the collection of a small amount 
of liquid in this tub will help to confirm my hypothesis.  However, 
should you see any liquid on the floor, be EXCEEDINGLY cautious .... it 
is likely a mixture of hydrogen peroxide, sulfuric acid, and 
hydrochloric acid!  That's certainly what it was when I cleaned it up 
this morning.  While I believe that any leakage will be caught in the 
tub or absorbed by the pads that I've placed under the sink, I can't 
guarantee that.  The actual amount of liquid should be small .... I only 
cleaned up 100-200 ml this morning, but it will likely be acidic.

One other thing: there is a sign on the spin rinse dryer saying that it 
has been shutdown pending replacement of an EEPROM to fix periodic 
nitrogen flow but that it could be turned back on.  The controller has 
been turned back on and, as a result, this spin rinse dryer should be 
perfectly functional .... despite what the sign says.

Finally, there was a report from last evening that we were low or out of 
a variety of chemicals.  I believe that all chemicals have been restocked.

Happy processing,

John