[labnetwork] Triscroll pump question

[Paolini, Steven]

I have some experience with these. First of all, depending on use, you can expect 6 months to one year of service out of these which I find unacceptable. Second of all, the fluorinated hydrocarbon residue is a mixture of o-ring material and Teflon from the tip seals. After rebuilding a bunch of them, I saw the same stuff in every pump housing and it was a dark powdery substance. I can't explain the inlet screen blowing outwards (upstream?) unless there was an event in your exhaust somewhere downstream.
Hope this helps,
Steve Paolini
Harvard University Center For Nanoscale Systems.

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr.
Sent: Wednesday, June 06, 2012 7:49 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Triscroll pump question

Hi All,

We had a very interesting event happen 2 weeks ago on our Oxford tool. We have an Oxford PECVD/RIE tool. PECVD chamber on the left side for PECVD Nitride, Load in the center, RIE on the right hand side.

The turbo on the load lock crashed and we discovered that the Varian Triscroll backing pump was off and the circuit breaker tripped.. We sent the pump out for repair and the inside of the pump was covered with black soot, it seems that the Pump had some sort of combustion event. The screen was blown outwards and it had a large hole in it. The only gas the load has in N2.

When the pump self destructed it back-streamed gas into the load lock, we had the residue analyzed, and  it was fluorinated hydrocarbon. We are completed stumped, has any of you had a TriScroll combust before.

Thanks in advance for any help.

Rick


Rick Morrison
Senior Member Technical  Staff
Group Leader Microfabrication Operations
Draper Laboratory
555 Technology Square
Cambridge, MA  02139

W  617-258-3420
C   508-930-3461

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