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<p class="MsoNormal">My $0.02,<o:p></o:p></p>
<p class="MsoNormal">Black marks on the back of a wafer are not normal. I agree that there must have been a material change by the supplier perhaps to “value engineer” there consumables. What IS normal is O-rings growing a black crud on their surfaces. This
is simply O2 attacking organics regardless of the O-rings being out of the “ line of sight” of the plasma. A downstream etcher (two 90 degree gas shifts), will experience the same effect at a slower rate. We inspect them and if not cracked, we clean them up
until the wipes show minimum crud and put them back in for more service.<o:p></o:p></p>
<p class="MsoNormal">Oh yeah, I wholeheartedly agree with Julia that we should not forget that the LUR with backside He is the
<i>overall </i>LUR of the chamber and you could be mislead by some other fine leak not associated with the He seal.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><span style="font-size:14.0pt">Steve Paolini<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Principal Equipment Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Harvard University Center for Nanoscale Systems<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">11 Oxford St.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Cambridge, MA 02138<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">617- 496- 9816<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">spaolini@cns.fas.harvard.edu<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">www.cns.fas.harvard.edu</span><span style="font-size:14.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> labnetwork-bounces@mtl.mit.edu <labnetwork-bounces@mtl.mit.edu>
<b>On Behalf Of </b>Mark Weiler<br>
<b>Sent:</b> Wednesday, March 06, 2019 10:18 AM<br>
<b>To:</b> Noah Clay <nclay@upenn.edu><br>
<b>Cc:</b> Fab Network <labnetwork@mtl.mit.edu><br>
<b>Subject:</b> Re: [labnetwork] STS DRIE Multiplex Lip Seal failures<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Noah, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We have the first version of the 100mm STS Multiplex DRIE whereby the wafer is mechanically clamped with weighted ceramic fingers, and the wafer is lifted with a tripod. Our LUR is 0.00 mTorr/min when new, but rises to 15-20 mT/m within
a week. We have an older HBC controller that indicates 6.5 for pressure at 2.33 flow rate... I apologize but don’t know the units for either. If these values are incorrect, it could be because they were adjusted to ensure a leak rate would pass. I will
need to go back over a decade in the logs to see if any changes were made over time...but, our rates and results have been consistent.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I believe the issue is material related, because we have our chamber lid o-ring and bottom ceramic o-ring failing with the same symptoms.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Mark<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
<div id="AppleMailSignature">
<p class="MsoNormal"><b>Mark Weiler</b><br>
Equipment & Facilities Manager <o:p></o:p></p>
<div>
<p class="MsoNormal">Claire and John Bertucci Nanotechnology Laboratory<br>
Electrical and Computer Engineering | Carnegie Mellon University<br>
<a href="x-apple-data-detectors://3/1">5000 Forbes Ave., Pittsburgh, PA 15213-3890</a><br>
T: <a href="tel:412.268.5430">412.268.2471</a><br>
F: <a href="tel:412.268.3497">412.268.3497</a><br>
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.ece.cmu.edu_&d=DwMGaQ&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=t7HorgNjXk4V-6m_P8F1UoRXoyMkEleQx7WVKYxreVA&s=i62eu2c6bno0Xe4sH3YpYnU2wd_7O1xBtpg2DbBFxDg&e=">www.ece.cmu.edu</a><br>
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__nanofab.ece.cmu.edu_&d=DwMGaQ&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=t7HorgNjXk4V-6m_P8F1UoRXoyMkEleQx7WVKYxreVA&s=ltoSF70VzK-YU-BI1rqnTp6iKgKIYVF_gDu1-r_Lk4E&e=">nanofab.ece.cmu.edu</a><o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
On Mar 6, 2019, at 09:19, Noah Clay <<a href="mailto:nclay@upenn.edu">nclay@upenn.edu</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Mark, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I have seen blackening on the back of the wafer when clamping is poor. Most recently, this was due the e-chuck having been etched excessively and/or polymer redep on the chuck from the endpoint clean step (cleans used to be run without
a wafer; we now use SiC). <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">What are your backside He leak rate set points and actual values? We run our etch process at -5C...(SPTS Rapier platform).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks,<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Noah<o:p></o:p></p>
<div id="AppleMailSignature">
<p class="MsoNormal">Sent from my iPhone<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
On Mar 5, 2019, at 15:44, Mark Weiler <<a href="mailto:mweiler@andrew.cmu.edu">mweiler@andrew.cmu.edu</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Hello Everyone, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We have gone through seven new lip seals purchased form Orbotech/SPTS. They are often failing before we even finish qualifying the system, or within a month thereafter.
<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Our our process is stable with power and parameters not deviating over the past decade. However, I ordered the most recent batch of lip seals because the wafer seals we had been using were coming out with black residue after only a few
runs… however, the current ones do the same. Not only have the lips seals disintegrated, but the chamber lid o-ring and bottom ceramic spool o-ring have also failed with black rubber material shedding off. It’s as if they are made of Buna and not meant for
this application.<o:p></o:p></p>
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<div>
<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">Our process is typical Bosch with 100 sccm C4F8 and 20 sccm O2 for etching switching off with ~50 Sccm SF6 for passivation at a processing pressure of 15 mTorr, Coil power 600-800W, Platen power 100-150W, Bias voltage 50-100v (up to 200
peak-to-peak), Platen temp at 19 degrees, Lid temp 41 degrees. Qual wafers are new bare Silicon. Etch rates are normal and stable with 10+ years of data…. we just can’t complete the work due to failing seals.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">Our chamber base pressure is between 1E-8 and 5E-8 Torr each morning. When we put in a brand new seal and run only the LUR, it passes with 0.00 mTorr/minute leak rate. That jumps to 3.00 mTorr/m after only 30 minutes of the SPTS recommended
O2 Clean… then rises as time and more runs progress. Wafers are coming out with black rings on their backsides. <o:p></o:p></p>
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<div>
<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">This should not be happening, and I believe it is due to incorrect material of the lip seals and o-rings. I am pinging the network, though, to see if there might be a parameter change we need to effect that may assist us.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Have any of you seen this before?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Best regards,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Mark<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">________________________________________________________________<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Mark Weiler<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Equipment & Facilites Manager<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Clair and John Bertucci Nanotechnology Laboratory<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Eden Hall Nanofabrication Cleanroom<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Carnegie Mellon University<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">P: 412-268-2471<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nanofab.ece.cmu.edu&d=DwMGaQ&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=t7HorgNjXk4V-6m_P8F1UoRXoyMkEleQx7WVKYxreVA&s=-aVoqu9RiTIm9cjvA88pAA8CfrdycT4AoTgEm_qp8hI&e=">http://www.nanofab.ece.cmu.edu</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><br>
</span><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__www.linkedin.com_in_marksbasics&d=DwMGaQ&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=t7HorgNjXk4V-6m_P8F1UoRXoyMkEleQx7WVKYxreVA&s=yI38qZlDy_Ubr2PUVtwfgDDQRJKod8Tta6_CMCMvW9M&e="><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif"><images.png>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
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