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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi Adithi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In addition to the good advice already given, you might also consider thermal issues if your problem is the metal not lifting off. Evaporating Pt (especially up to 250 nm) can result in significant substrate heating, particularly if your samples are not heatsinked. I clamp my samples to a large block of aluminum flattened on a surface plate and that solved my thermal issues (along with sensible deposition rates).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Matt<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='color:#7F7F7F;mso-style-textfill-fill-color:#7F7F7F;mso-style-textfill-fill-alpha:100.0%'>Postdoc<o:p></o:p></span></p><p class=MsoNormal><span style='color:#7F7F7F;mso-style-textfill-fill-color:#7F7F7F;mso-style-textfill-fill-alpha:100.0%'>van der Weide Group<o:p></o:p></span></p><p class=MsoNormal><span style='color:#7F7F7F;mso-style-textfill-fill-color:#7F7F7F;mso-style-textfill-fill-alpha:100.0%'>UW-Madison<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></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 <labnetwork-bounces@mtl.mit.edu> <b>On Behalf Of </b>Noah Clay<br><b>Sent:</b> Friday, January 4, 2019 1:17 PM<br><b>To:</b> ADITHI U <uadithi@iisc.ac.in><br><b>Cc:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> Re: [labnetwork] Metallization on rough ceramic substrates<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hello Adithi,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>As you know, ceramics can be quite porous and metal adhesion can be diminished by surface/internally adsorbed water, organics, etc. Therefore, you may consider deep solvent cleaning, other surface treatments as appropriate (e.g., plasma) for your material and a lengthy dehydration bake prior to resist application. If pre-resist cleaning proves ineffective, then after resist development, you may consider O2 plasma or, if available, in-situ ion bombardment. Lastly, given the rough topography of your substrate, there may be undeveloped or underexposed pockets of resist on the substrate, which necessitate optimizing bake, exposure and develop conditions.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>As for HMDS (mainly used for Si), without knowing the type of ceramic you’re using, I can’t say that it will be effective as an adhesion promoter. I very humbly/respectfully disagree with previous comments that HMDS is used mostly for etching, but agree that to facilitate liftoff, a relatively thick LOR layer should be spun and baked before application of imaging resist.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Best,<o:p></o:p></p></div><div><p class=MsoNormal>Noah Clay<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><i>Singh Center for Nanotechnology </i><o:p></o:p></p></div><div><p class=MsoNormal><i>University of Pennsylvania </i><o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><i>Philadelphia, PA</i><o:p></o:p></p><div id=AppleMailSignature><p class=MsoNormal>Sent from my iPhone<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Jan 4, 2019, at 08:51, Hitesh Kamble <<a href="mailto:hit.kamble@gmail.com">hit.kamble@gmail.com</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal>Hello Adithi,<o:p></o:p></p><div><p class=MsoNormal> In case of HMDS ,it will improve adhesion but resists will not remove easily from surafce.HMDS is mostly use in etching. Since you're having rough surface, <span style='font-family:"Arial",sans-serif'>Instead of HMDS use LOR 3B or say liftOFF resists which helps to improve liftoff process.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>Also for 250nm metallization you need more than 2um thick resists.</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>We did not do this on ceramic samples exactly but successfully did liftoff on etched/textured glass and etched samples(roughness more than~400nm).</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>Following are my suggestions:</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>-Time Interval between litho and deposition should be lowest as possible</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>- Dehydration at higher temp and for longer time.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>-LOR 3B coating at lower rpm and gradually increase rpm.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>-Keep sample in Remover PG and heat at 80C for 5min or more if metal not lifted,(Sonication not recquired in most cases)</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>Thanks,</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>Hitesh Kamble</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial",sans-serif'>IITBNF-IIT Bombay</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><div><p class=MsoNormal>On Fri 4 Jan, 2019, 6:08 PM ADITHI U <<a href="mailto:uadithi@iisc.ac.in">uadithi@iisc.ac.in</a> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div id="m_-8304701522397863792divtagdefaultwrapper"><p style='margin:0in;margin-bottom:.0001pt'><span style='font-size:12.0pt;color:black'>Dear All,<o:p></o:p></span></p><p style='margin:0in;margin-bottom:.0001pt'><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p style='margin:0in;margin-bottom:.0001pt'><span style='font-size:12.0pt;color:black'> We are having difficulties in doing metal(Ti/Pt) lift off on ceramic substrates. Does any of you have experience on fabricating metal patterns on the rough Ceramic Substrates. Below are the details of the process done.<o:p></o:p></span></p><p style='margin:0in;margin-bottom:.0001pt'><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p><p style='margin:0in;margin-bottom:.0001pt'><span style='font-size:12.0pt;color:black'> The roughness of the ceramic substrates were approximately 400nm. We had used HMDS as adhesion promoter for lithography, the thickness of the Photoresist was ~ 1.5um.The thickness of the Ti/Pt layer was ~ 250nm. Immediately after lithography the deposition was done followed by 48 hours of lift off(Acetone) process. Ultrasonication(5-10mins) in Acetone was done after 48hours. <o:p></o:p></span></p><div id="m_-8304701522397863792Signature"><div id="m_-8304701522397863792divtagdefaultwrapper"><pre><b><span style='font-size:12.0pt;font-family:"Arial",sans-serif;color:#222222'>Best Regards</span></b><span class=m-8304701522397863792hoenzb><span style='font-size:9.0pt;font-family:"Arial Black",sans-serif;color:#888888'><o:p></o:p></span></span></pre><div><pre><b><span style='font-size:12.0pt;font-family:"Arial",sans-serif;color:#222222'><br><br>Adithi.U<br>Senior Facility Technologist,<br>National Nano Fabrication Centre,<br>CeNSE, Indian Institute of Science<br>Bangalore</span></b><span style='font-size:12.0pt;font-family:"Arial",sans-serif;color:#222222'><o:p></o:p></span></pre></div><p class=MsoNormal><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></p></div></div></div></div><p class=MsoNormal>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu" target="_blank">labnetwork@mtl.mit.edu</a><br><a href="https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork" target="_blank">https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></blockquote></div></div></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><a href="https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork">https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></div></blockquote></div></div></body></html>