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Bruce:<br>
<br>
While it has been a number of years, we used to have a Varian 350D
in which we ran phospine, arsine and boron trifluoride. It also had
a DP on the source that was backed by a little 5.6 CFM (as I recall)
Alcatel mechanical pump. To the best of my knowledge, however, I
don't think that we ever ran Fomblin in that pump. I think that we
always ran it only on normal hydrocarbon "white" oil. My
recollection, however, was that we only changed oil in the backing
pump every 4-6 months and used to get years of life out of it. We
used to change pump oil when that little pump couldn't hold the
foreline pressure lower than about 30 microns of mercury. I may be
able to dig up some old logs to confirm that those numbers are about
right.<br>
<br>
I also vaguely recall that we tried using Fomblin in a pump on a
LPCVD nitride system at one point, got some sort of crystallization
in that .... and went back to hyrdocarbon oil. Note: we DO use
Fomblin in most of our pumps that are still wet pumps so I am not
"anti-Fomblin" in any way.<br>
<br>
Hopefully someone who is a bit more of a chemist than I may be able
to comment ... but I think that it may be worth asking the question:
is Fomblin the best fluid to use in this application.<br>
<br>
Good luck,<br>
<br>
John<br>
<br>
<div class="moz-cite-prefix">On 6/6/2014 4:44 AM, Bruce Tolleson
wrote:<br>
</div>
<blockquote
cite="mid:91CE152971DAD64F890FD8BE59734DB72FBEACAD@ex03mail01.ad.rit.edu"
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<div class="WordSection1">
<p class="MsoNormal">We have a Varian 350D Ion Implanter. We
are using Phosphine and Boron-tri-fluoride in our processes
with a diffusion pumped source and a wet backing pump
(Fomblin serviced). We have noticed over the years that our
wet pump will only last about 4-6 months before needing a
rebuild. We check pH regularly, and flush and fill when
needed. We find that we have a crystallization of sorts
occurring in the pump that is killing the pumps.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is there anyone out there that is using
this tool or this process that has had or is having this
issue and has rectified it?
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any suggestions are appreciated.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank You,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Bruce E.
Tolleson<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Rochester
Institute of Technology<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">82 Lomb
Memorial Drive, Bldg 17-2627<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Rochester, NY
14623-5604<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">(585) 478-3836<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:navy"><img
id="Picture_x0020_1"
src="cid:part1.05040300.07020700@stanford.edu"
alt="http://www.rit.edu/~962www/logos/tiger_walking_rit_color.jpg"
height="60" width="90"></span><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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