[labnetwork] Cambridge/Ultratech/Veeco Savannah ALD - stop valve issues?

[Hathaway, Malcolm R]

Hi Tim,

Yes, this issue is endemic to these units, as all the deposition gases pass over the sealing surfaces of the valve under normal operating conditions.

One solution is to maintain a stock of the appropriate (but expensive) Kalrez-type orings, and do a valve sealing-face cleanup at intervals.  Eventually, however, you will find that deposition has encrusted the interior of the valve bellows, rendering it much less flexible than original equipment.

I am happy to share with you via PM some plumbing "rearrangements" that we have instituted which seem to have helped this problem greatly.

Sincerely,


Mac Hathaway
Senior Process and Systems Engineer
Harvard CNS
________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Tim Gilheart <gilheart at rice.edu>
Sent: Tuesday, March 30, 2021 6:13 PM
To: Fab Network <labnetwork at mtl.mit.edu>
Subject: [labnetwork] Cambridge/Ultratech/Veeco Savannah ALD - stop valve issues?

Greetings,

I’m hoping that several teams on this list have relevant experience to share, since I know a number of you manage Savannah ALD tools.

Our tool has presented with leakage issues through the stop valve twice in the past 6 months. We replaced the last valve at the end of Aug 2020, and have recently again experienced issues with failing to vent (due to the valve not closing completely and the vac pump still pulling on the chamber).

We have a temporary workaround in place (an external manual valve on the pump line), but this leakage through the stop valve effects process outcomes and has proven costly to address, since valve replacement seems to be the recommended solution.

Our tool typically runs Al2O3, HfO2, TiO2, and ZnO processes, sometimes ZrO2. Stop valve heating jacket is maintained at the recommended 150 C, and the heaters all seem to be working properly.

Does anyone have suggestions about maintaining these stop valves for longer? Or, failing that, a referral for refurbishing them? I am willing to consider a solution that involves swapping out valves 1-2/year and sending them out for rebuild if that’s an option for a reasonable cost.

Thanks in advance for any advice you can share,

--
Tim Gilheart, Ph.D.
Research Scientist - Nanofabrication Cleanroom Manager,
Shared Equipment Authority (SEA), Rice University
Cell: 832-341-5488 | Office: 713-348-3159 | gilheart at rice.edu<mailto:gilheart at rice.edu>

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