<div dir="auto">Definitely try the developer first. If it has not been cross linked by the exposure then it will clean up easy. But if it’s been exposed, you’ll need piranha solution. </div><div dir="auto"><br></div><div dir="auto">To prevent sticking in the future, make sure your tweezers cannot leave an impression after the soft bake once the wafer has cooled to room temperature. If they leave an impression, you’ll need to soft bake more. </div><div dir="auto"><br></div><div dir="auto">Good luck!<br clear="all"><br clear="all"><div dir="auto"><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr">Robert Nidetz, PhD (he/him/his)</div><div>University of Michigan</div><div dir="ltr">LNF User Liaison and Domain Expert</div><div dir="ltr">1241 EECS Building</div><div dir="ltr">1301 Beal Ave</div><div>Ann Arbor, MI 48109</div><div><a href="mailto:nidetz@umich.edu" target="_blank">nidetz@umich.edu</a><br></div><div>734.496.8065</div><div dir="ltr"><div>Book an appointment: <a href="https://calendly.com/nidetz" target="_blank">https://calendly.com/nidetz</a></div></div></div></div></div></div><div><br></div><div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, Feb 12, 2026 at 7:36 PM Phillip Bauer <<a href="mailto:Phillip.Bauer@formfactor.com">Phillip.Bauer@formfactor.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Hello</div>
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I am somewhat new to SU-8 working with Positive resists throughout my career. I agree with data sheets are just guideline, for processing. I saw a note from another University to run a 65 deg post bake after the 95 deg soft bake. My question is about mask
cleaning. Is Sulfuric/Peroxide (Piranha ~ 60-90C) really needed. I would think the PGMEA or PGMEA/Acetone followed by IPA would be an effective clean. Just wanted to poll the audience. </div>
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</a><p style="line-height:1.38;margin:0in 0in 8pt"><span style="font-family:Aptos,sans-serif;font-size:12pt;color:rgb(0,0,0)"><b>Thank you,</b></span></p>
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<b>Phillip Bauer </b></div>
<p style="line-height:1.38;margin:0in 0in 8pt"><span style="font-family:Aptos,sans-serif;font-size:12pt;color:rgb(0,0,0)">Principal Photolithography Process Engineer</span></p>
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<a href="https://www.google.com/maps/search/4350+Innovation+Drive+%0D%0A+%0D%0AFarmers+Branch,+Texas+75244?entry=gmail&source=g">4350 Innovation Drive</a></div>
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Farmers Branch, Texas 75244</a></div>
<p style="line-height:1.38;margin:0in 0in 8pt"><span style="font-family:Aptos,sans-serif;font-size:12pt;color:rgb(70,120,134)"><u><a style="color:rgb(70,120,134);margin-top:0px;margin-bottom:0px" href="mailto:phillip.bauer@formfactor.com" target="_blank">phillip.bauer@formfactor.com</a></u></span></p>
<p style="line-height:1.38;margin:0in 0in 8pt"><span style="font-family:Aptos,sans-serif;font-size:12pt;color:rgb(0,0,0)">M: 682 521 0874</span></p>
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