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We actually made a TikTok about this subject recently that went somewhat viral. Despite the off-color humor it seems relevant to the discussion
<a href="https://www.tiktok.com/@micronanolouisville/video/7214338192995061034" id="LPlnk468094">
https://www.tiktok.com/@micronanolouisville/video/7214338192995061034</a> These wafers were cleaned in a 60C NMP bath and it was clear that the HMDS was still on the surface.
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> on behalf of Cohen, Ana N CTR USARMY DEVCOM ARL (USA) <ana.n.cohen.ctr@army.mil><br>
<b>Sent:</b> Tuesday, March 28, 2023 6:40 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu <labnetwork@mtl.mit.edu>; Gustavo de Oliveira Luiz <deolivei@ualberta.ca><br>
<b>Subject:</b> Re: [labnetwork] Strange "sample memory" with LOR 5B</font>
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<div class="PlainText">CAUTION: This email originated from outside of our organization. Do not click links, open attachments, or respond unless you recognize the sender's email address and know the contents are safe.<br>
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Michael got me thinking... Gustavo, could you confirm the DI water rinse<br>
after the piranha looks as you'd expect? I'm not 100% certain the chemistry,<br>
but since HMDS is more a surface treatment than a residue remaining on the<br>
wafer I'm curious if it actually could be unaffected.<br>
<br>
I have definitely seen this 'ghosting' after I solvent strip a patterned<br>
wafer and then need to rinse with DI water. Any water collected on the wafer<br>
surface would match wherever resist had previously been, presumably due to<br>
remaining HMDS. I've not seen it impact further patterning before, but I've<br>
also not used the LOR in my tests and may also have run less tests per<br>
wafer. I'd actually found the following information from EPFL on reworking<br>
HMDS-treated wafers a little while ago when testing out our lab's HMDS<br>
quality (don't know who over there figured this out, but thanks to whoever<br>
did!)<br>
<a href="https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.epfl.ch%2Fresearch%2Ffacilities%2Fcmi%2Fprocess%2Fphotolithography%2Fhmds-ap&data=05%7C01%7Cmichael.martin%40louisville.EDU%7C1eb5be3d74d4448b451008db301b632d%7Cdd246e4a54344e158ae391ad9797b209%7C0%7C0%7C638156666427001449%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=eTd2IROmftQa49qtYImK3w7CZVOBRwfw2tr9ncJOn%2BI%3D&reserved=0">https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.epfl.ch%2Fresearch%2Ffacilities%2Fcmi%2Fprocess%2Fphotolithography%2Fhmds-ap&data=05%7C01%7Cmichael.martin%40louisville.EDU%7C1eb5be3d74d4448b451008db301b632d%7Cdd246e4a54344e158ae391ad9797b209%7C0%7C0%7C638156666427001449%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=eTd2IROmftQa49qtYImK3w7CZVOBRwfw2tr9ncJOn%2BI%3D&reserved=0</a><br>
plication/<br>
<br>
Either way, the O2 plasma during the cleaning process should be worth a<br>
shot!<br>
<br>
--<br>
Ana N. Cohen [she/her/hers]<br>
Photolithography Cleanroom Technician<br>
Contractor | General Technical Services, LLC<br>
US Army Research Laboratory<br>
2800 Powder Mill Road, Adelphi, MD 20783<br>
Tel: 301-394-1527<br>
Email: ana.n.cohen.ctr@army.mil<br>
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