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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'>Rick:<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'>Holy lightning bolt you do seem to have a discharge problem. You didn’t say if the wafer has oxide on both sides but assuming it does I would suggest stripping the oxide on the chuck side to avoid the charging problem you seem to have. An electrostatic chuck works much better if you have a conductive material or in this case a semiconductor material than a dielectric. Assuming you also helium backside cooling with your E-chuck this should also allow you to etch the oxide that is patterned without the need to run multiple cycles. Depending on the RF power you might have to lower it a bit to avoid reticulation of the photo resist. I also don’t understand why you are using 8 microns of resist as 1-2 microns should suffice assuming the resist: oxide selectivity is around 3:1. If you care to share your process recipe I might be able to help out some more. Bob Henderson<o:p></o:p></span></p><p class=MsoNormal><span style='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"'> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Morrison, Richard H., Jr.<br><b>Sent:</b> Wednesday, March 04, 2015 5:08 AM<br><b>To:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> [labnetwork] Need help with RIE process<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi everyone,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a strange problem that I need some help with. We have an Ulvac NE-550 RIE system with an electrostatic chuck. The wafer is a double sided polish with 1um of SiO2. One side has an AZ4620 resist pattern 8um thick to etch the 1um of oxide. Because the process runs hot we break the etch into 9 different steps and move into the LL after every step. On the polished side that is down on the ESC check we have craters on the surface that look like a lightning strike or meteor strike, this is fairly deep several microns.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have attached a photo of the damage. Have any of you seen anything like this? I need to fix the issue because the side that is down ends up being the frontside of the wafer and that is a killer defect. We think the oxide is charging and when the lift pins come up (at ground potential) we get a discharge.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Rick<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Draper Laboratory<o:p></o:p></p><p class=MsoNormal>Principal Member of the Technical Staff<o:p></o:p></p><p class=MsoNormal>Group Leader Microfabrication Operations<o:p></o:p></p><p class=MsoNormal>555 Technology Square<o:p></o:p></p><p class=MsoNormal>Cambridge Ma, 02139-3563<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><a href="http://www.draper.com">www.draper.com</a><o:p></o:p></p><p class=MsoNormal><a href="mailto:rmorrison@draper.com">rmorrison@draper.com</a><o:p></o:p></p><p class=MsoNormal>W 617-258-3420<o:p></o:p></p><p class=MsoNormal>C 508-930-3461<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div class=MsoNormal align=center style='text-align:center'><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><hr size=2 width="100%" align=center></span></div><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'>Notice: This email and any attachments may contain proprietary (Draper non-public) and/or export-controlled information of Draper Laboratory. If you are not the intended recipient of this email, please immediately notify the sender by replying to this email and immediately destroy all copies of this email. <o:p></o:p></span></p><div class=MsoNormal align=center style='text-align:center'><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><hr size=2 width="100%" align=center></span></div></div></body></html>