[labnetwork] Ion Implanter Varian 350D

[Volkan Ozguz]

Hello Bruce
Same here too! I have operated, repaired several early Varian implanters
between 1980-1995. We didn't use Fomblin and we didn't have any particular
problems even under heavy usage.  This may  be a mismatch with Fomblin and
parts of an older type pump.
Volkan

Volkan Ozguz
Sabanci Univ
Nanotechnology Research and Application Center
Tel: 90 216 483 9834
Email: vozguz at sabanciuniv.edu


On 7 Haz 2014, at 15:31, "Luciani, Vincent" <Vincent.Luciani at nist.gov>
wrote:

 Hello Bruce,
John may have something there.  I was the caretaker of an ion implanter for
over 10 years using the same fluorides with a DP and a wet pump with "white
oil" .  It was used heavily and the pumps lasted many years at a time.  Not
an explanation but a similar story.

Vince




On Jun 6, 2014, at 7:27 PM, "John Shott" <shott at stanford.edu> wrote:

 Bruce:

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.

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.

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.

Good luck,

John

On 6/6/2014 4:44 AM, Bruce Tolleson wrote:

  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.



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?



Any suggestions are appreciated.





Thank You,





Bruce E. Tolleson

Rochester Institute of Technology

82  Lomb Memorial Drive, Bldg 17-2627

Rochester, NY 14623-5604

(585) 478-3836

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