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Hi Richard --<br>
<br>
A similar problem was observed and diagnosed on one of our O2 ashers
by one of our industrial labmembers who was a plasma etch engineer
at HP. The cause seems to have been trace amounts Fomblin pump
fluid coming back into the chamber -- Fomblin is basically a
polymerized freon, so there's your fluorine source.<br>
<br>
Mary<br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
Paul G. Allen Room 136, Mail Code 4070
Stanford, CA 94305
(650)723-9980
<a class="moz-txt-link-abbreviated" href="mailto:mtang@stanford.edu">mtang@stanford.edu</a>
<a class="moz-txt-link-freetext" href="http://snf.stanford.edu">http://snf.stanford.edu</a></pre>
<br>
<br>
On 7/27/2011 4:58 AM, Morrison, Richard H., Jr. wrote:
<blockquote
cite="mid:94CDEF5D18F0BB4A85B1D78EFBDD6FDA0469538B@exchbk1.draper.com"
type="cite">
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<div>
<p>Hi Everyone, </p>
<p> </p>
<p>Our facility uses an STS RIE tool (100mm wafers), to etch
Nitrides/Oxides/Ti and resist cleans. I have a big problem
when we use O2 to clean off resist from wafers. It seems that
just running O2 plasma we etch 1000A/min of SiO2. It should be
impossible to etch SiO2 with O2 plasma. </p>
<p> </p>
<p>In trouble shooting we have done the following, change the
Teflon wafer holder, disconnected the SF6, CF4 and CHF3 tanks
and capped the lines, then pumped the machine down and just
ran O2 and we still etched the SiO2 at 1000A/min. We have a
plasma scope and the F peak is clipped of in height during the
O2 plasma clean? </p>
<p> </p>
<p>Does anybody have any ideas on what may be going on. </p>
<p> </p>
<p>Thanks in advance, </p>
<p>Rick </p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<p>Rick Morrison </p>
<p>Senior Member Technical Staff </p>
<p>Acting Group Leader Mems Fabrication </p>
<p>Draper Laboratory </p>
<p>555 Technology Square </p>
<p>Cambridge, MA 02139 </p>
<p> </p>
<p>617-258-3420 </p>
<p> </p>
</div>
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