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<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Hi Adithi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Adding to all other comments and in particular you need to pay attention to the profile of the photoresist: for a good lift-off you need some undercut. You didn’t mention the feature
size of the metallisation pads but assuming it is more than 3 µm in any dimension you may need to consider using a negative resist as the undercut can be tailored to your need using longer development time. We use maN 1420 (about 2 ↨0m thick) for lift-off
processes and that works fine.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Regards,
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Fouad Karouta<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">*************************************<o:p></o:p></p>
<p class="MsoNormal">Manager ANFF ACT Node<o:p></o:p></p>
<p class="MsoNormal">Australian National Fabrication Facility<o:p></o:p></p>
<p class="MsoNormal">Research School of Physics and Engineering<o:p></o:p></p>
<p class="MsoNormal">L. Huxley Building (#56), Mills Road, Room 4.02<o:p></o:p></p>
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<p class="MsoNormal">Tel: + 61 2 6125 7174<o:p></o:p></p>
<p class="MsoNormal">Mob: + 61 451 046 412<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Email: <a href="mailto:fouad.karouta@anu.edu.au">
fouad.karouta@anu.edu.au</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="http://anff-act.anu.edu.au/">http://anff-act.anu.edu.au/</a><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>mdwyer87@gmail.com<br>
<b>Sent:</b> Monday, 7 January 2019 1:48 AM<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></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">Hi Adithi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">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></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Matt<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#7F7F7F">Postdoc<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#7F7F7F">van der Weide Group<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#7F7F7F">UW-Madison<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> <a href="mailto:labnetwork-bounces@mtl.mit.edu">
labnetwork-bounces@mtl.mit.edu</a> <<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>>
<b>On Behalf Of </b>Noah Clay<br>
<b>Sent:</b> Friday, January 4, 2019 1:17 PM<br>
<b>To:</b> ADITHI U <<a href="mailto:uadithi@iisc.ac.in">uadithi@iisc.ac.in</a>><br>
<b>Cc:</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> Re: [labnetwork] Metallization on rough ceramic substrates<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Hello Adithi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">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></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">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></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Best,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Noah Clay<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><i><span lang="EN-US">Singh Center for Nanotechnology </span></i><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><i><span lang="EN-US">University of Pennsylvania </span></i><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><i><span lang="EN-US">Philadelphia, PA</span></i><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Sent from my iPhone<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><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></span></p>
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<p class="MsoNormal"><span lang="EN-US">Hello Adithi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"> 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><span lang="EN-US" style="font-family:"Arial",sans-serif">Instead
of HMDS use LOR 3B or say liftOFF resists which helps to improve liftoff process.</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">Also for 250nm metallization you need more than 2um thick resists.</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" 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><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">Following are my suggestions:</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">-Time Interval between litho and deposition should be lowest as possible</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">- Dehydration at higher temp and for longer time.</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">-LOR 3B coating at lower rpm and gradually increase rpm.</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" 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><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">Thanks,</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">Hitesh Kamble</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Arial",sans-serif">IITBNF-IIT Bombay</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">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></span></p>
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<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-US" style="color:black">Dear All,<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-US" style="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:0cm;margin-bottom:.0001pt"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-US" style="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>
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<pre><b><span lang="EN-US" 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>
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<pre><b><span lang="EN-US" 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>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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