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<p>Hello Filippo.</p>
<p><br>
</p>
<p>All sputter systems are different but here are my experiences:</p>
<p><br>
</p>
<p>I never had any issues with real cross-sputtering (material from
a neighboring, non active target being accidentally deposited).
Typical sputter targets have grounded shields / chimneys around
them and a shutter on top, together with the plasma forming
magnets underneath your active target this reliably prevents
non-active targets from sputtering.<br>
There are two risks though: If you have several densely package
sputter guns, you risk depositing some of material A during
sputtering onto inactive gun B. If you then sputter from gun B
later you will get material B + a bit of A. This is pressure
dependent but especially at higher Ar pressures some of your
sputtered atoms will make a U-turn. To prevent this make sure the
gap between shutter and chimney of all guns is as small as
possible, and always run your target a bit against the closed
shutter for cleaning.<br>
A similar issue can arise if you have two or more guns active
simultaneously: some material from A can deposit on B and will
thus be co-sputtered by gun B. You will not even notice that
during your process as you want to deposit both materials anyways.
But after co-depositing you should run all targets for some
minutes of sputter time in an empty chamber to make sure their
targets are clean again.</p>
<p><br>
</p>
<p>Lithographic resist in a UHV sputter system: Depends on your
definition of UHV. If for you UHV means 10^-10 mbar or better, you
need to bake out anything you bring into the chamber, including
your resist covered samples. That will likely destroy / reflow
/... the resist anyways. If you are fine with 10^-8 mbar and
therefore do not require strict bake-outs, most lithographic
resists I have used are totally fine to be sputtered upon (there
are many resist though, so there could be exceptions). I am
referring to resists that have seen post-exposure bake-out before
going into the vacuum chamber, reducing the risk of out-gassing
during sputtering.<br>
But if very sensitive samples are run in a sputter system, resist
is usually banned, not necessarily because of the resist itself
but because a resist covered sample by definition is not as clean
as possible (it can't be sonicated / plasma-cleaned / ...) and
therefore risks contaminating the chamber with anything that
accidentally sits on the resist.<br>
</p>
<p><br>
</p>
<p>The use of Kapton tape in a 10^-8 mbar or better sputter system
is not recommended: The sample surface will likely get warm during
sputtering, risking the glue underneath the Kapton to evaporate
and deposit anywhere in the system, potentially contaminating
future samples. I have never tried Crystalbond myself though.</p>
<p><br>
</p>
<p>Hope that helps.<br>
Gerhard.</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 11/08/2026 03:13, #MARTINELLI
FILIPPO# wrote:<br>
</div>
<blockquote type="cite"
cite="mid:PUZPR01MB516505E7E232F97CC2E7889FEADD2@PUZPR01MB5165.apcprd01.prod.exchangelabs.com">
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Dear labnetwork community,</div>
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<br>
</div>
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I have recently been put in charge of a UHV magnetron sputtering
system (AJA Orion) that I need to maintain and operate. The
machine is dedicated to co-sputtering of two metals in a
nitrogen environment.</div>
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<br>
</div>
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The previous operator strongly advised me to be careful about
what goes into the chamber, as contamination can affect both the
chamber condition and the properties of the deposited material.
However, she was not very specific about what exactly causes
contamination, and I am unsure how restrictive I should be with
the materials I load.</div>
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<br>
</div>
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I have a few questions I would appreciate your opinion on:</div>
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<br>
</div>
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1. I read that cross-sputtering can occur between nearby
substrates, or between the substrate and the chamber. In your
opinion, are there materials that are particularly prone to
cross-sputtering and hard to remove with standard cleaning
routines, and that should therefore be avoided in the chamber
altogether?</div>
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<br>
</div>
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2. Following on from that, what is your take on lithography
resists?</div>
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<br>
</div>
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3. How about mounting materials such as Kapton tape or
Crystalbond?</div>
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<br>
</div>
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I am quite new to this, so any suggestion or recommendation is
welcome. I look forward to hearing your opinions.</div>
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<br>
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Cheers,</div>
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Filippo</div>
<br>
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