Our experiences with Dry and wet pumps are exactly the opposite. Our 2 dry
pumps (they happen
to be Edwards) are VERY reliable. They have been running essentially
untouched for 2 years in heavy chlorine use.
Most wet pumps on the other hand have short life under heavy chlorine use,
even with fomblin, oil filtration, ballast, etc. It would be quite abnormal
for one to last a year without major failure. We have a few exceptions to
that, but that is the general case. Backstreaming should not be a problem
if the pump is properly purged and loaded with N2.
The dry pumps have been well worth the expense.
Lynn Rathbun
CNF
>X-Organization: MIT Microsystems Technology Laboratories
>
>Dear All,
>
>We are getting an Electron Cyclotron Resonance Plasma Etcher which will use
>Cl_2 and BCl_3 (among other gases). For pumping, we will get a magnetically
>levitated turbopump. Our question concerns the backing pump for the turbo;
>namely choice between an oil-pump or a dry-pump.
>
>The backstreaming of the oil is the main disadvantage of the oil-pump. The
>disadvantages of the dry pump (according to a couple of people who have used
>them) are:
>
>1. They are about $15K more expensive
>
>2. They break down more often (corrosion may have more catastrophic result
> because of their tight tolerances?)
>
>Do you have any experience/advice?
>
>Sincerely,
>
>Jim Sturm and Mansour Shayegan
>sturm@ee.princeton.edu, shayegan@ee.princeton.edu
>
*****************************************************
Dr. Lynn Rathbun, a.k.a. Big Dog
User Program Manager Voice (607)-255-2329 ext 110
Cornell Nanofabrication Fac.
FAX(607)-255-8601
Knight Laboratory-Cornell University email Rathbun@cnf.cornell.edu
Ithaca, New York 14853
http://www.cnf.cornell.edu/
Webmaster at Christian World Adoption http://www.cwa.org/cwa.html
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