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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Ron,
<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>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#1F497D">I believe in your case, you are more concerned about switching from one application to another and not so concerned about sequentially using fluorine and chlorine in the same
application, right? In addition to Jim’s comments about removing oxides in Poly Si etching, when I worked at Lam Research, the gate-level polysilicon etch tools used HBr and chlorine chemistries and the chamber cleans in the same chamber always used fluorine-based
gases such as NF3. The protocol for going from one application to another was a fluorine based chamber clean followed by the cycling of application specific dummy wafers. I am unaware of any failure physics/mechanisms of using both chemistries and it will
be interesting to hear others respond to this. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#1F497D">Also, as Jim pointed out, for III/V processing, many fabs use chlorine/methane/hydrogen type processes that form polymers on just about everything in the chamber, including the
mask on the wafer. My own data for low volume III/V processing showed that when I used fluorine based chemistry to open dielectric masks, followed by a chlorine-based ICP etch to etch III/V compounds, we had issues with etch rate and profile control (I should
have talked to Jim before trying this!).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#1F497D">Regards, Scott</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><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>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>James P McVittie<br>
<b>Sent:</b> Thursday, November 08, 2018 5:58 PM<br>
<b>To:</b> Reger, Ronald K <rreger@purdue.edu>; labnetwork@mtl.mit.edu<br>
<b>Subject:</b> Re: [labnetwork] Mixing Fluorine and Chlorine Chemistries<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p><span style="font-family:"Calibri",sans-serif;color:black">Ron, <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">1. F in an etch chamber from previous etch runs can slow down a Cl2 etching process. This is of most concern to III-V users. So for a well-controlled Cl2 etch process you want to
get all the F based polymers out of the chamber. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">2. In Poly Si etching C2F6, CF4 or NF3 are often used to remove surface oxides before start the HBr / Cl2 Si etch.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">3. " Small amounts of CF4 (5-10 sccm) are added to the standard BCl3/Cl2/N2 process for residue removal. In some cases (particularly for copper residue), CF4 appears to widen the
process window for residue control.CF4 typically helps to eliminate open field residue, but there have been cases where CF4 helped with dense area residue as well. Since the addition of another gas introduces more variables to the process, the use ofCF4 should
be minimized." From old AMT Metal (Al) Etch Process Manual <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> In the Stanford Nanofabrication Facility (SNF) we have F containing gases in all our Cl2 etchers. Our Cl2 Si etchers have CF4 and C2F6. Our ICP metal etcher has CF4, and Our III-V
etcher has SF6. <o:p></o:p></span></p>
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<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p style="background:white"><span style="font-family:"Calibri",sans-serif;color:black">James (Jim) McVittie, Ph.D.<o:p></o:p></span></p>
<p style="background:white"><span style="font-family:"Calibri",sans-serif;color:black">Senior Research Engineer<o:p></o:p></span></p>
<p style="background:white"><span style="font-family:"Calibri",sans-serif;color:black">Electrical Engineering<o:p></o:p></span></p>
<p style="background:white"><span style="font-family:"Calibri",sans-serif;color:black">Stanford University<o:p></o:p></span></p>
<p style="background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222">336x Paul G. Allen Bldg</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p style="background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222">420 Via Palou Mall </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p style="background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222">Stanford, CA 94305</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p style="background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222"><a href="mailto:mcvittie@stanford.edu">mcvittie@stanford.edu</a></span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p style="background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222">650-725-3640</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">
<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a> <<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>> on behalf of Reger, Ronald K <<a href="mailto:rreger@purdue.edu">rreger@purdue.edu</a>><br>
<b>Sent:</b> Thursday, November 8, 2018 10:45 AM<br>
<b>To:</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> [labnetwork] Mixing Fluorine and Chlorine Chemistries</span><span style="font-family:"Calibri",sans-serif;color:black">
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> <o:p></o:p></span></p>
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<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black">Dear Colleagues,</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black"> </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black">Here at the Birck Nanotechnology Center we have a Panasonic E620 RIE ICP etcher that uses a variety of gases for etching of various materials. It has capability
to do both chlorine-based and fluorine-based processes. This has given us a lot of versatility for a wide variety of materials. We’re now exploring the implications of using both chemistries in the same etcher, particularly when it comes to making electron
devices. </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black"> </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black">We had done a small survey of a few other facilities and are finding a mixed response….. some facilities use dedicated etchers to keep these chemistries separated
while others have both gases in the same etcher and use one type of recipe or the other. Particularly for electron devices are there cross-contamination issues/models with using both gases in the same chamber? What would be the failure physics/mechanisms
from this? If both chemistries are used in the same system are there standard protocols between switching etch chemistries that we need to follow?</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black"> </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black">Any advice would be greatly appreciated as we’re getting into more electron device processing!</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black"> </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black">Thanks,<br>
Ron</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-family:"Microsoft PhagsPa",sans-serif;color:black"> </span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-family:"Microsoft PhagsPa",sans-serif;color:black"> </span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-size:14.0pt;font-family:"Microsoft PhagsPa",sans-serif;color:black">Ron Reger</span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><i><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:black">Engineering Manager</span></i><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:black">Birck Nanotechnology Center | Room 2289 |</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:black">Office:</span></b><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:black">
</span><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:#0070C0">765.494.6667
</span><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:black">|
<b>Email:</b> </span><span style="font-size:9.0pt;font-family:"Calibri",sans-serif;color:#0070C0"><a href="mailto:rreger@purdue.edu" id="LPlnk752018"><span style="color:#0070C0">rreger@purdue.edu</span></a></span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-family:"Calibri",sans-serif;color:black">Wiki:
</span><span style="font-family:"Calibri",sans-serif;color:#0070C0"><a href="https://wiki.itap.purdue.edu/display/BNCWiki" id="LPlnk828453"><span style="color:#0070C0">https://wiki.itap.purdue.edu/display/BNCWiki</span></a></span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-family:"Calibri",sans-serif;color:black">iLabs:
</span><span style="font-family:"Calibri",sans-serif;color:#0070C0"><a href="https://purdue.ilabsolutions.com/homepage/" id="LPlnk689837"><span style="color:#0563C1">https://purdue.ilabsolutions.com/homepage/</span></a></span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:9.0pt;font-family:"Corbel",sans-serif;color:black">______________________________________________________________</span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-size:5.0pt;font-family:"Calibri",sans-serif;color:black"> </span><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-family:"Calibri",sans-serif;color:black"><img border="0" width="300" height="66" id="x_Picture_x0020_1" src="cid:image001.png@01D47795.B73DA550" alt="Purdue_University-150_Years_of_Giant_Leaps.png (300×66)"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-size:14.0pt;font-family:"Calibri",sans-serif;color:black"> </span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-family:"Calibri",sans-serif;color:black"><a href="http://www.purdue.edu/giantleaps" id="LPlnk561057"><span style="color:#0563C1">www.purdue.edu/giantleaps</span></a></span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><b><span style="font-family:"Calibri",sans-serif;color:black"> </span></b><span style="font-family:"Calibri",sans-serif;color:black"><o:p></o:p></span></p>
<p class="xmsonormal"><span style="font-family:"Calibri",sans-serif;color:black"> <o:p></o:p></span></p>
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