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    <div class="moz-cite-prefix">Bob,<br>
      I don't expect this to resolve the issue. Some type<br>
      of downstream deposit is the price of admission<br>
      for any of our etch or deposition tools.<br>
      However, I would like to open the following question:<br>
      <br>
      At UC Berkeley (and I presumed most other labs ?)<br>
      we use 10% O2 with our SF6 etch step.<br>
      This provides oxygen for minimizing sulfur<br>
      build up in the foreline - we still get deposits but<br>
      they are not as bad as with no O2. I had presumed this<br>
      was common strategy. There is some decrease in selectivity<br>
      due to resist erosion - but it has been worth it. Greater <br>
      concentrations of O2 lead to too much resist loss.<br>
      <br>
      I welcome feedback on this recipe and encourage <br>
      addition of some O2 if not using any.<br>
      <br>
      Bill Flounders<br>
      UC Berkeley<br>
      <br>
      <br>
      <br>
      Bob Henderson wrote:<br>
    </div>
    <blockquote
      cite="mid:527abd66.c9e2440a.1282.2aacSMTPIN_ADDED_BROKEN@mx.google.com"
      type="cite">
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        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Has
            anyone considered using an oxygen/fluorine plasma for
            removal of the polymer. Since most DRIE systems have an ICP
            source a fair amount of O/F will be generated that can be
            used to etch away the carbon rich polymer maybe as far as
            the gate valve and turbopump. The reactive species probably
            won’t have a lifetime that will extend very far down the
            foreline but I have seen downstream plasmas that will go a
            few feet into the foreline before extinguishing. Bob
            Henderson<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <div>
          <div style="border:none;border-top:solid #B5C4DF
            1.0pt;padding:3.0pt 0in 0in 0in">
            <p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
                <a class="moz-txt-link-abbreviated" href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>
                [<a class="moz-txt-link-freetext" href="mailto:labnetwork-bounces@mtl.mit.edu">mailto:labnetwork-bounces@mtl.mit.edu</a>] <b>On Behalf Of
                </b>Aebersold,Julia W.<br>
                <b>Sent:</b> Tuesday, November 05, 2013 10:50 AM<br>
                <b>To:</b> Ian Harvey; <a class="moz-txt-link-abbreviated" href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
                <b>Subject:</b> Re: [labnetwork] Bosch etch foreline and
                pump powder residue question...<o:p></o:p></span></p>
          </div>
        </div>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Ian,
            we noticed the same when we had to replace our turbo pump
            (very expensive) and were careful with the byproducts from
            the buildup from the etching process.  It is recommended and
            we installed a heater on the line from the roughing/backing
            pump to the turbo, so that the byproducts do not condense
            and are properly exhausted.   The particles can also buildup
            on your foreline valve causing it to become stuck or not
            actuate.<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></p>
        <div>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Cheers!<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Julia
              Aebersold, Ph.D. <o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">MNTC
              Cleanroom Manager<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Shumaker
              Research Building, Room 233<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">2210
              South Brook Street<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">University
              of Louisville<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Louisville,
              KY  40292<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif"">502-852-1572<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif""><a
                moz-do-not-send="true"
                href="http://louisville.edu/micronano/">http://louisville.edu/micronano/</a><o:p></o:p></span></p>
        </div>
        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></p>
        <div>
          <div style="border:none;border-top:solid #B5C4DF
            1.0pt;padding:3.0pt 0in 0in 0in">
            <p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
                <a moz-do-not-send="true"
                  href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>
                [<a moz-do-not-send="true"
                  href="mailto:labnetwork-bounces@mtl.mit.edu">mailto:labnetwork-bounces@mtl.mit.edu</a>]
                <b>On Behalf Of </b>Ian Harvey<br>
                <b>Sent:</b> Monday, November 04, 2013 6:36 PM<br>
                <b>To:</b> <a moz-do-not-send="true"
                  href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
                <b>Subject:</b> [labnetwork] Bosch etch foreline and
                pump powder residue question...<o:p></o:p></span></p>
          </div>
        </div>
        <p class="MsoNormal"><o:p> </o:p></p>
        <div>
          <div>
            <p class="MsoNormal">Dear Labnetwork colleagues,<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <p class="MsoNormal">We are installing a used STS DRIE tool
              acquired from the used tool market and used for Bosch-Si
              etch.  <o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <p class="MsoNormal">We are unsettled by the large amount of
              white powder collected in the foreline and inside the
              large turbopump.  The turbo is becoming unbalanced as
              flakes come off, and we are getting ready to trade in the
              large maglev pump for a refurb, and clean the forelines.<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <p class="MsoNormal">Does anyone have experience with what
              the powder is (F-C-S-O / EDS analysis attached), its
              risks, and how to safely manage it during pump removal,
              packing and declaration for shipping?<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <p class="MsoNormal">Thanks!<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <p class="MsoNormal">Ian<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
          </div>
          <div>
            <div>
              <div>
                <div>
                  <div>
                    <div>
                      <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black">********************************************<br>
                          Ian R. Harvey, Ph.D.<o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black">Associate
                          Director, Utah Nanofab <o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black"> &<o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal"><span
style="font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black">Micron
                          Microscopy Core<o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black">2511
                          SMBB (USTAR)<o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal" style="margin-bottom:12.0pt"><span
style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black">University
                          of Utah<o:p></o:p></span></p>
                    </div>
                    <div>
                      <p class="MsoNormal" style="margin-bottom:13.5pt"><span
style="font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black">801/585-6162
                          (voicemail)<br>
                          801/581-5676 (lab main number)<br>
                          <a moz-do-not-send="true"
                            href="http://www.nanofab.utah.edu">www.nanofab.utah.edu</a><o:p></o:p></span></p>
                    </div>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </div>
        <div>
          <p class="MsoNormal"><o:p> </o:p></p>
        </div>
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      <pre wrap="">_______________________________________________
labnetwork mailing list
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<a class="moz-txt-link-freetext" href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a>
</pre>
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