[labnetwork] Contamination control in PVD systems

[Noah Clay]

Carsen,

Here are a few guidelines that have worked over the years:

1. Don't mix metals, polymers and dielectrics in thermal and/or e-beam evaporators.  Holding the line on this is tough, but I've always tried to minimize cross contamination.

2. Disallow materials containing: Zn, P and As.  Weird PVD requests emerge all of the time and it's good to maintain an "anything goes" system, but stay away from the above.

3. Keep one e-beam system free of magnetic materials (even Ni).  The condensed matter physicists will be happy.

4. Don't go cheap on sputtering system hardware.  To the extent reasonable, keep separate gun hardware for each target or class of materials.  

5. Bead blast shields, gun hardware, etc. routinely...as for the frequency, it should be based on use, not time, unless your use is very steady.

6. Remove and clean any e-beam hearths at least once each year.

7. Every now and then, I cave in on a user's request to evaporate a material that I'm uncomfortable with...we let them run and then change shielding immediately after they are done. Sometimes we reserve a system for them for 1 to 2 days, line the walls with UHV foil and do a full tear down when they're done.  As a rule, we RGA fingerprint the system before and after and try to align this with routine maintenance.

8. Staff-maintained loadlocked systems are the best for contamination control.  At 3am on Sunday morning, for all I know, someone is evaporating radioactive peanut butter.

I hope this helps.

Best,
Nosh

On January 31, 2015 6:48:10 PM EST, Fouad Karouta <fouad.karouta at anu.edu.au> wrote:
>Dear Carsen,
>
>Here at the Australian National University, Canberra, we do have an
>open access e-beam evaporator reserved for metals and we started with:
>Au, Pt, Ni, Ti, Ge, Al, Cr and later we added Pd, Mo, Hf and Nb.
>So far we haven't heard from our users any negative feedback about
>deterioration/contamination of contacts.
>We do not allow oxides nor metals like Zn, Cu, Te, Sn etc. where we
>believe these metals have a more serious contamination risk. In our
>facility we do have a sputter system w/o materials restriction and it
>is used for metals to oxides, nitrides offering more than 50
>materials/targets. We do know from users that some contamination is
>found at level clearly below 1%.
>
>Hope this helps a bit and I am curious to learn from others their
>experience.
>
>Cheers,
>Fouad Karouta
>
>*********************************
>Manager ANFF ACT Node
>Australian National Fabrication Facility
>Research School of Physics and Engineering
>Australian National University
>ACT 0200, Canberra, Australia
>Tel: + 61 2 6125 7174
>Mob: + 61 451 046 412
>Email: fouad.karouta at anu.edu.au
>http://anff-act.anu.edu.au/
>
>-----Original Message-----
>From: labnetwork-bounces at mtl.mit.edu
>[mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Carsen Kline
>Sent: Sunday, 1 February 2015 5:02 AM
>To: labnetwork at mtl.mit.edu
>Subject: [labnetwork] Contamination control in PVD systems
>
>Hello all,
>
>We're looking to expand our PVD capabilities and we're curious to know
>how other labs control contamination as it relates to safety, process,
>and equipment condition. Can anyone share your general philosophy or
>policies on approaching contamination control in PVD systems? (For
>example, categorizing systems based on allowed contaminants, or having
>multiple levels of controlled access to specific tools, etc.)
>
>Thanks for your input, I'm looking forward to your responses.
>
>Carsen
>
>
>
>
>Carsen Kline
>Stanford Nanofabrication Facility
>http://snf.stanford.edu
>carsen at stanford.edu
>
>
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-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.
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