[labnetwork] How to charge for sputtering target use

[Darick Baker]

We have tried a few different models. I don't know that any are
particularly even to everybody, but the users know the parameters before
they do their depositions so they typically aren't surprised and I haven't
gotten many complaints.

In one of our systems where we change targets pretty regularly, we have
users record kW Hrs and then scale the weight change of the target by kW
Hrs used. The cost per gram is based on the target cost and an overhead
fee. We use this method because grabbing the information from the software
is easy for the users. On average, in our system, this works out to about
$6 per Watt Hour and people can typically get a reasonable cost estimate
using that number.

In another system where the targets are only accessed rarely, we currently
charge by thickness deposited (~$1/nm). The users self-report this number
and overall have been very accurate. Almost everyone using that system uses
the same recipe so I can tell by deposition times how thick they were
trying to deposit and I typically audit these numbers once a year. I have
found almost as much over-reporting as under-reporting of the thickness. I
could see this method not working in some places, but I am very lucky with
our lab culture here. We are working on a way to automatically grab kWHr
information from the tool logs and bill using that. This will mean less
work for me and for the users. That process is about 90% together; we have
started testing it and I expect it to go live at the next target change.

Prior to having gold and platinum sputtering, our users were already used
to being charged for evaporated gold by weighing a shared crucible before
and after deposition. Perhaps adding the sputter charges in a way that
required less work on the user's part that weighting the crucible made it
more palatable.

We do not temper any of our cost calculations based on potential for money
coming back due to reclaim during shield cleaning.

Let me know if you have any other questions. I'm actually pretty interested
to know what other labs are doing.

On Thu, Jun 4, 2020 at 1:58 PM Chang, Long <lvchang at central.uh.edu> wrote:

> Hi All,
>
> At UHNF, each user owns their own sputtering target. We are currently
> considering a shared model for expensive targets like Au, Pt, etc. Does
> anyone have a reasonable way to estimate material usage vs something we can
> track so that we can charge fairly? What approaches do y’all take to manage
> how expensive material is shared?
>
> Thanks,
> Long
>
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-- 
Darick Baker, PhD
Research Engineer
Washington Nanofabrication Facility
University of Washington
Fluke Hall 115, Box 352143
(206) 221-8265
Pronouns: he/him
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