[labnetwork] Metered chemical dispensing?

[Aaron Hryciw]

Hi all,

In our open-access cleanroom, we provide common chemicals "free of charge",
in the sense that there is no additional charge to use them apart from the
tool time (e.g., hourly rate for wet deck login).  This includes such
chemicals as acetone, IPA, photoresist developers, standard metal wet
etchants, KOH, etc.; the cost of supplying the chemical is (at least in
principle) wrapped up into the tool rate.  I believe that this is a fairly
standard approach among cleanrooms in academic settings.

A shortcoming of this approach is that high-volume chemical users are being
charged the same as low-volume chemical users; there is also no (financial)
incentive for users to limit their chemical usage to just the volume they
need.  We are therefore looking into ways in which we can capture the
actual volume of chemicals used by each user, at least for some high-value
and/or high-volume chemicals, such that billing for chemical usage can be
applied more fairly.  As global supply chain issues have increased the cost
of chemicals, this is becoming even more important.

Ideally, the method of capturing usage should be largely automated (e.g.,
not just a physical chemical use logbook at each wet deck), such that it
does not take a lot of staff bandwidth to administrate, and should not rely
on the honour system only (e.g., logging usage of a material in our lab
management software), to ensure compliance.

One approach we have been considering is having some kind of metered
chemical dispensing.  For instance, the piranha wet deck would be plumbed
with dispensers (e.g., chemical-compatible metering pumps) for sulfuric
acid and hydrogen peroxide, perhaps drawing from large drums of the stock
chemicals housed remotely (e.g., in a subfab or service chase).  A
qualified user would login to the dispenser (via our lab
management software), dispense the required volumes of the chemicals,
logout, and the volume used would be tracked and automatically logged to
their account.

I expect that such a scheme is not as simple as it seems, and that there
are probably a host of engineering, software, and other logistical problems
that would need to be solved to implement this safely and effectively, at
least if a turnkey solution for this does not already exist.  Has anyone
implemented anything like this in their own cleanroom?  Or is this a
horribly over-engineered solution to a relatively minor problem?  I'd be
very interested in hearing how others have dealt with the problem of
charging users fairly for chemical usage.

Cheers,

 – Aaron




Aaron Hryciw, PhD, PEng

Fabrication Group Manager

University of Alberta - nanoFAB

W1-060 ECERF Building

9107 - 116 Street

Edmonton, Alberta

Canada T6G 2V4 Ph: 780-940-7938
www.nanofab.ualberta.ca
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