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Explosive oxidation of very pure thin films in a vacuum chamber is
known. Popping
sounds can be heard if a chamber used for depositing titanium or
aluminum is suddenly exposed to room air. Flash of light can also be
seen if the chamber is full of dust or peeling matter. Both can be
dangerous.
You have to set up protocols for slow venting, waiting for a
long time ( hour or hours) to allow for slow passivation of unoxidized
materials, and then opening the chamber. Vent and pump cycles may help
too. Check with your vendor. <br>
<br>
Slow venting may reduce peeling and release of particles. You have to
allow the whole system to reach room temperature (or slightly above RT)
before venting it. However, some peeling of material will occur and
the chimney and chamber walls/parts will have to be cleaned thoroughly
using a dedicated vacuum cleaner. Again protocols for this will
have to be set up. You may follow processes/precautions used to clean
similar equipment such as CVD chambers or ion implant source chambers.
Color of the flakes depends on the composition and surface finish.
"Black" may not mean anything. It may be an off stoichiometric
deposition with residual gas contamination that may vary with position
in the chamber. <br>
<br>
Smells are hard to track down unless you sample the gas and analyze.
Complex species are formed if you are doing anything reactive in the
chamber. Smells can arise from back streaming of some vapors from a
pumping station. Check with the vendor. Repeated cycles of venting
and rough pump down without opening the door will help to
reduce the concentration of smelly components. (Plasma etch chambers
tend to have unusual odors. Well exhausted bench,
hood, enclosure etc has to be used to clean such chambers. A mask is
needed to.)<br>
<br>
Vendor websites used to have info on such topics. If you did not
download and save it, most of it is gone because of the newer style of
websites.
<a class="moz-txt-link-freetext" href="http://www.asm.com/index.php?option=com_content&task=view&id=51&Itemid=67">http://www.asm.com/index.php?option=com_content&task=view&id=51&Itemid=67</a><br>
<br>
Hope this helps. <br>
<br>
Pramod C Karulkar<br>
Fairbanks Alaska<br>
907 457 4123<br>
443 622 4425 <br>
<br>
Keith Bradshaw wrote:
<blockquote
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<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">We are getting a strong
smell from the chamber and instant
oxidation and flaking of product deposited on the chimney of our
Sputtering
system when changing the Cad-Tel target.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">What is done to avoid
this?<o:p></o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">Is this smell harmful?<o:p></o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">The flakes are very dark
and seem to form when we open the
system up to atmosphere. It is load locked so normally it doesn’t
see air.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></p>
<p class="MsoAutoSig"><font face="Times New Roman" size="3"><span
style="font-size: 12pt;">Keith Bradshaw<o:p></o:p></span></font></p>
<p class="MsoAutoSig"><font face="Times New Roman" size="3"><span
style="font-size: 12pt;">972-883-2099<o:p></o:p></span></font></p>
<p class="MsoAutoSig"><font face="Times New Roman" size="3"><span
style="font-size: 12pt;">RL 10<o:p></o:p></span></font></p>
<p class="MsoAutoSig"><st1:PlaceType w:st="on"><font
face="Times New Roman" size="3"><span style="font-size: 12pt;">University</span></font></st1:PlaceType>
of <st1:PlaceName w:st="on">Texas</st1:PlaceName> at <st1:City
w:st="on"><st1:place w:st="on">Dallas</st1:place></st1:City>
Clean Room<o:p></o:p></p>
<p class="MsoAutoSig"><font face="Times New Roman" size="3"><span
style="font-size: 12pt;">NSERL building<o:p></o:p></span></font></p>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span
style="font-size: 12pt;"><o:p> </o:p></span></font></p>
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