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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">The same thing happened at Draper the FSE sent coolant into the backside cooling line after a PM. It was pumping down and the pressure rose and we shut it down
before the liquid entered the vacuum lines ect, we do not have a scrubber. The cleanup was very stressful, the entire ESC chuck was removed and cleaned with solvents and the chamber wiped down many times over several days. We monitored the cleaning by running
wafers with a O2 plasma process. We monitored for any liquid on the wafer backside and residue on the chamber walls.<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">If I remember it took us a week of running and cleaning to return the chamber back to normal. I think we changed out the esc chuck to be on the safe side. We
were lucky in that it did not get into the vacuum system.<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">Rick<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"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Draper
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Principal Member of the Technical Staff<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">555 Technology Square<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Cambridge Ma, 02139-3563<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">www.draper.com<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">rmorrison@draper.com<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">W 617-258-3420<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">C 508-930-3461<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>Peter Köllensperger<br>
<b>Sent:</b> Monday, August 22, 2016 4:15 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] Flooded ICP-RIE<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">Dear Labnetwork Members,<o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">I’ve just recently started as process group leader here at NTNU NanoLab in Trondheim, Norway, but have been following the discussions on the mailing list with interest.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">I now have a question of my own and would very much appreciate any thoughts or advice you may be able to share.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">We are currently having preventive maintenance of our ICP-RIE systems carried out by the manufacturer.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Unfortunately one of their engineers mixed up the helium backing line with the coolant line from the chiller unit. When the chiller was switched on, it pumped ca. 1-2 litres of a water and Hexid heat transfer fluid into
the main chamber and loadlock. The system was not under vacuum at the time. The RIE section was completely filled with water and the main chamber also had water in it. The lifting pins assembly including bellows, the CM gauge the pirani gauge as well as the
He line were completely submerged.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">The engineers realised what was going on after the chiller gave a low level alarm and they saw the coolant level continue to drop. They stopped the chiller, opened the chamber, and mopped up the liquid with PIG pads and
cleanroom cloths where accessible. They then switched on both the roughing and loadlock pump.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">When the loadlock pump was switched on it died immediately. They realised that water vapour shouldn’t enter the scrubber and removed the exhaust line from the scrubber, but it is likely that some water vapour ++ entered
the scrubber as steam was coming out of the exhaust. This means the entire system has been exposed to water/coolant mix, possibly with exception of the turbo pump, although there may have been some backstreaming from the main roughing pump.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Pumping the chamber <a href="x-apple-data-detectors://1">from Thursday</a> to the following Tuesday improved the vacuum from 1x10e-2 Torr with a leakup rate of 20 mTorr/min to 5x10e-5 Torr with a leakup rate of 5 mTorr/min.
Specification is less than 1 mTorr/min.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Needless to say this causes a number of issues, some of which we may not even have thought to consider.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB">In our view, the issues can be divided into immediate Health and Safety concerns, and more long term concerns regarding the performance of an ICP RIE unit that has been flooded</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoListParagraph" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt">
<span lang="EN-GB">1. Regarding H&S issues we’re concerned about are the mixing of SF6, CHF3, Cl2 and BCl3 with water in the scrubber.</span><o:p></o:p></p>
<p class="MsoListParagraph" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt">
<span lang="EN-GB">We will send the scrubber for a refill and check. We have contacted the vendor of the scrubber, his main concern is clogging of the granulate. Is there anything else we should pay attention to?</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoListParagraph" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt">
<span lang="EN-GB">2. Can a chamber be sufficiently reconditioned by in situ by cleaning, baking and running plasmas or will the coolant inside necessitate a more complete disassembly and clean?</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span lang="EN-GB">Has anyone had a similar problem and how did you proceed? How would you suggest we ask the manufacturer to verify that there are no long-term detrimental effects on the instrument, the pumps
or the processes run on the instrument?</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal">I'd appreciate any thoughts you may have surrounding this issue. <o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"><br>
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</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="DE">Kind regards,</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="DE"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="DE">Peter</span><o:p></o:p></p>
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<p class="MsoNormal">Dr. Peter A. Köllensperger<o:p></o:p></p>
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<p class="MsoNormal">NTNU NanoLab<o:p></o:p></p>
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<p class="MsoNormal">Sem Sælandsvei 14<o:p></o:p></p>
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<p class="MsoNormal">Norwegian University of Science and Technology (NTNU)<o:p></o:p></p>
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<p class="MsoNormal">7491 Trondheim<o:p></o:p></p>
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