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<div class="moz-cite-prefix">All,<br>
I welcome the pump purge recommendations and support we all use <br>
our best discretion regarding number of cycles, length of time
etc.<br>
Document what you did for your own records.<br>
<br>
I disagree with using the term "hazardous waste" for the phosphine
tubing. <br>
This sets a precedent in our community that I do not see as
justified.<br>
It carries an increased disposal cost and handling concerns.<br>
If you believe the material is potentially contaminated then I
encourage <br>
you to propose reasonable and appropriate decontamination
procedure. <br>
You have everything you need in house to make this safe for pick
up.<br>
<br>
In General:<br>
I would pump/purge as recommended to insure safe for disassembly.<br>
Disassemble with appropriate PPE if you consider potentially<br>
contaminated. Treat with water, solvent, acid or base as
appropriate<br>
for decontamination and dispose as non hazardous waste.<br>
<br>
Due to the high volatility of PH3, I would not consider the
pumped/purged<br>
tubing hazardous. If you wanted additional assurance, rinse with
water<br>
or alcohol. To verify non hazardous, rinse with water and pH test
the liquid.<br>
Even for a low volatility acid gas such as BCl3, I wouldn't
consider the<br>
tubing hazardous waste. But I would document that I gave it a
rinse with<br>
mild sodium hydroxide solution, rinsed and pH tested prior to
disposal.<br>
<br>
Bill Flounders<br>
UC Berkeley<br>
<br>
<br>
<br>
<br>
Paolini, Steven wrote:<br>
</div>
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<div class="WordSection1">
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Excellent
question.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
cannot quote industry standards nor am I aware any exist,
but the bottom line is many pump and purge cycles are in
order. I would use the system for the pumping part of the
procedure since it will pump well below what the venturi can
provide at the cabinet. I would say that the exact # of
cycles is up to you and your available time. If I were
challenged with this, I would pump the lines down to the
lowest level of vacuum achievable through your system and
still allow it to remain there for at least a half hour (or
more if your delivery lines are longer than 50 feet) since
there are always some stubborn molecules of gas that have to
crash into bends and ultimately enter the chamber. I would
then run pure N2 through the MFC’s at full scale for another
half hour before repeating the cycle. I would do this at a
minimum of 20 cycles.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">In
regards to disposal, I would treat the Phosphine lines as
hazardous waste but the Silane lines should be relatively
non-toxic aside from possible deposits of SiO2 (dusting). I
hope that other subscribers can correct me if I am wrong
about this but my methods have been successful over the
years.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Best
of luck and be careful,<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Steve
Paolini<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Equipment
dood<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Harvard
Center for Nanoscale Systems.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a class="moz-txt-link-abbreviated" href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>
[<a class="moz-txt-link-freetext" href="mailto:labnetwork-bounces@mtl.mit.edu">mailto:labnetwork-bounces@mtl.mit.edu</a>]
<b>On Behalf Of </b>Hmelo, Anthony B<br>
<b>Sent:</b> Friday, September 09, 2016 9:42 AM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Cc:</b> Hmelo, Anthony B<br>
<b>Subject:</b> [labnetwork] Decommissioning Silane and
Phosphene Stainless Gas Delivery Lines<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">All: <o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">VINSE is in the process of relocating a
PECVD reactor to a new cleanroom facility and I am seeking
advice on the industry standards for decommissiong Silane
and Phosphene stainless gas delivery lines that run from the
respective gas cabinets to the tool in its current location.
Beyond thoroughly purging the lines with nitrogen flow
through the tool and exhausting the purge gas through the
tool exhaust, are there other considerations involved in
abandoning the gas delivery lines? For example, are the
lines considered to be permanently contaminated and will
they require special disposal?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Any advice on decommissioning these lines
will be deeply appreciated.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">With thanks,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<div>
<p class="MsoNormal"><span style="color:black">Anthony B
Hmelo, PhD<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span style="color:black">Associate
Director, VINSE<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black">Research
Associate Professor of Physics and Astronomy<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black">Research
Associate Professor of Materials Science and
Engineering<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black">Vanderbilt
University<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black">Nashville
TN 37235<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span
style="color:black">615-343-7212<o:p></o:p></span></p>
</div>
</div>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
<br>
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