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<p>Long:</p>
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<p>I would estimate the dose ratio between PMMA and ZEP to be closer to 4 or 5 to 1. ZEP definitely has a shelf life, 1-2 years, maybe longer. It has much better etch resistance than PMMA. It is expensive. </p>
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<p>CSAR from All Resists is very similar and much cheaper, it requires about 20% more dose than ZEP.</p>
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<p>Regards,</p>
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<p>Mark K Mondol <br>
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<font color="3366FF">Mark K Mondol<br>
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<div><font color="3366FF">Assistant Director NanoStructures Laboratory <br>
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<div><font color="3366FF">And <br>
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<div><font color="3366FF">Facility Manager Scanning Electron Beam Lithography Facility
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<div><font color="3366FF"> mondol@mit.edu <br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> on behalf of Chang, Long <lvchang@Central.UH.EDU><br>
<b>Sent:</b> Thursday, April 29, 2021 10:28 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] ZEP worth it?</font>
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<div>Hi Guys,
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<div class="">I have no experience with ZEP, but the data sheet suggest a critical dose of ~35 uC/cm2, approximately 1/10 of PMMA. What are the problems with ZEP and under what conditions is it worth the cost? Does it last forever in storage like PMMA?</div>
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<div class="">Thanks,<br class="">
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Long</div>
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