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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi Leif,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>We get a lot of requests for PDMS in our lab, and we do allow users to process PDMS coated wafers/chips as well as cured PDMS molds. However, we have a lot of restrictions in place in order to mitigate the same concerns that you highlighted in your post. Our PDMS users are basically classified into two categories: thin-film and thick-film. The thin-film users are generally working with PDMS in the range of several microns or less. We allow spin-coating of these films in the cleanroom, but the users are restricted to a specific spinner and a specific hot plate. The thick-film users are working with hundreds of microns or even millimeters of PDMS. At the moment, we do not allow coating of such thick films in the cleanroom, as we found that it was simply too messy. They must coat and cure their samples outside the cleanroom. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Fully cured PDMS samples are allowed in certain process equipment, but again, we had to restrict users to a specific subset of tools, as we have seen and are continually concerned about contamination. These films do outgas, so users are restricted to one of two sputtering systems for deposition. Samples are typically placed on carrier wafers to avoid contact with the substrate table. In addition, we limit the range of sputtering powers that users can run in an attempt to mitigate heat at the sample. So far, we have not had any vacuum issues or problems with other standard films in these tools. We also have an RIE dedicated to “dirty” processes. Users are allowed to etch PDMS in this tool, but it does leave residue in the chamber that must be cleaned from time to time. In addition, users are restricted to a specific profilometer, as we found that even fully cured PDMS was contaminating the stylus in our other systems. <o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='color:#1F497D'>Uncured PDMS is not allowed in any of our tools, and heating of PDMS in any vacuum system is not allowed. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Hope this helps.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Best Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Matt</span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='color:#1F497D'>-- <br><b>Matthew T. Moneck, Ph.D.</b><br>Executive Manager, Carnegie Mellon Nanofabrication Facility<br>Electrical and Computer Engineering | Carnegie Mellon University<br>5000 Forbes Ave., Pittsburgh, PA 15213-3890<br>T: 412.268.5430<br>F: 412.268.3497<br><a href="http://www.ece.cmu.edu">www.ece.cmu.edu</a><br>nanofab.ece.cmu.edu<o:p></o:p></span></p></div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b>From:</b> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Leif Johansen<br><b>Sent:</b> Wednesday, November 25, 2015 3:58 AM<br><b>To:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> [labnetwork] How do you handle PDMS in a cleanroom environment?<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dear Lab Network, <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a dilemma. Polydimethylsiloxane (PDMS) is a promising material for soft lithography, and a lot of our users have a strong wish to process this material in our lab – especially for making nanoimprint stamps . However, before being cured, PDMS is basically a silicone oil, and all our front end engineers (plasma chambers, lithography etc. ) are really scared about this substance ending up in their equipment. Our back end engineers (especially the wire bonding engineer) is also strongly opposed to the introduction of PDMS into the back end lab. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Are there any experience out there in the community on how to handle PDMS in a cleanroom environment?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Best regards, <o:p></o:p></p><p class=MsoNormal>Leif<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=721 style='width:300.0pt;border-collapse:collapse'><tr><td width=721 colspan=2 valign=top style='width:300.0pt;padding:0in 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Leif S. Johansen <o:p></o:p></span></b></p></td></tr><tr><td width=721 colspan=2 valign=top style='width:300.0pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:#9B9B9B;mso-fareast-language:EN-GB'>Head of Operations<o:p></o:p></span></p></td></tr><tr><td width=721 colspan=2 valign=top style='width:300.0pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>DTU Danchip <o:p></o:p></span></p></td></tr><tr><td width=721 colspan=2 valign=top style='width:300.0pt;border:none;border-bottom:solid #AEAEAE 1.0pt;padding:0in 0in 0in 0in'><p class=MsoNormal style='mso-line-height-alt:0pt'><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'> <o:p></o:p></span></p></td></tr><tr><td width=631 valign=top style='width:262.5pt;padding:6.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Technical University of Denmark<o:p></o:p></span></b></p></td><td width=90 rowspan=7 valign=top style='width:37.5pt;padding:6.0pt 0in 0in 0in'><p class=MsoNormal align=right style='text-align:right'><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black'><img border=0 width=36 height=53 id="Picture_x0020_1" src="cid:image001.gif@01D12777.828B3E10" alt="http://www.dtu.dk/images/DTU_email_logo_01.gif"></span><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'><o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Danchip <o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Ørsteds Plads, Byg. 347 <o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>2800 Lyngby <o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Direct +45 45255713 <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'>Mobile +45 25348992<o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'><a href="mailto:lesjo@danchip.dtu.dk">lesjo@danchip.dtu.dk</a> <o:p></o:p></span></p></td></tr><tr><td style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-GB'><a href="http://www.danchip.dtu.dk/">www.danchip.dtu.dk/</a> <o:p></o:p></span></p></td></tr></table><p class=MsoNormal><span lang=DA><o:p> </o:p></span></p><p class=MsoNormal><span lang=DA><o:p> </o:p></span></p></div></body></html>