[labnetwork] EBeam Lithography on Glass substrates

Thu Aug 24 08:48:59 EDT 2017

Hi Marc,

We use 10nm of Cr on PMMA with no issues at all.  The Cr is deposited by 
e-beam deposition at a rate of 1A/s.  Then we use the Cr etchant for 
making standard photomasks to strip the Cr before the standard PMMA 
development.  Exposures from 10kV to 30kV show no issues or biasing from 
the additional Cr process steps.

Best Regards,
Brent

On 8/23/2017 7:14 PM, Fouad Karouta wrote:
> Dear Marc,
>
> Evaporating Au on PMMA or ZEP should be done in a thermal evaporator, an e-beam evaporator due to the electron beam would affect the resist. We also avoid sputtering for this application as the effect of Ar plasma (violet colour) can be unpredictable.
>
> Regards, Fouad
>
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Marc Zuiddam - TNW
> Sent: Wednesday, 23 August 2017 10:29 PM
> To: 'labnetwork at mtl.mit.edu' <labnetwork at mtl.mit.edu>
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
>
> Dear people,
>
> I always have the idea that sputting/evaporating a thin Au layer on my sample is exposing the e-beam resist on my sample.. Do you also experience that?
>
>   Regards, Marc Zuiddam
>
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Fouad Karouta
> Sent: woensdag 23 augustus 2017 1:42
> To: Jugessur, Aju S; labnetwork at mtl.mit.edu
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
>
> Hi Aju,
>
> Am echoing other voices:
> - We use 12 nm of Au mostly on top of PMMA/ZEP to do the EBL which we remove in a Ki/I2 solution.
> - Sometime we use Cr under resist layer as well when we need Cr for further processing.
>
> Regards, Fouad Karouta
>
> *************************************
> Manager ANFF ACT Node
> Australian National Fabrication Facility Research School of Physics and Engineering L. Huxley Building (#56), Mills Road, Room 4.02 Australian National University ACT 0200, Canberra, Australia
> Tel: + 61 2 6125 7174
> Mob: + 61 451 046 412
> Email: fouad.karouta at anu.edu.au
> http://anff-act.anu.edu.au/
>
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Lino Eugene
> Sent: Tuesday, 22 August 2017 11:49 PM
> To: labnetwork at mtl.mit.edu
> Cc: Steven Wei <c27wei at edu.uwaterloo.ca>
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
>
> Hi Aju,
>
> We have a coop student who has worked on different anti-charging materials: PEDOT:PSS, Electra 92 and sputtered Al.
>
> We had also adhesion and uniformity issues with PEDOT:PSS from Sigma-Aldrich. The solution was filtered and Triton X-100 was added and but no noticeable improvement. I was told that surface treatment with SurPass 3000 improves adhesion but we haven't tried this yet. Moreover, PEDOT:PSS cross-links under certain conditions and then the layer cannot be removed with water.
>
> 10-20 nm of sputtered Al should work well . The resistivity of 5 nm Al is expected to be high because of surface electron scattering (electron mean free path in Al at room temperature is ~19nm) and oxidation. We use MF-319 at room temperature or 40 degC  to remove the layer.
>
> Electra 92 from AllResist is easy to work with as it can be removed with DI water after EBL and gives pretty good results on PMMA and on ZEP520A. Surface treatment on HSQ is needed, so far treatment with IPA gives good results. Also, the price is reasonable compared to ESpacer and AquaSave.
>
> Best,
>
> Lino Eugene, Ph.D., Jr. Eng.
> Micro/nanofabrication process engineer
> Quantum NanoFab
> University of Waterloo
> 200 University Avenue West
> Waterloo, ON, Canada
> N2L 3G1
>   
> Ph: +1 519-888-4567 #37788
> Cell: +1 226-929-1685
> Website: https://fab.qnc.uwaterloo.ca/
>
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Matthew Moneck
> Sent: August 21, 2017 21:09
> To: Mark K Mondol <mondol at mit.edu>; labnetwork at mtl.mit.edu
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
>
> Hi Aju,
>
> We have commonly used Al as a conductive layer on top of PMMA on glass (removal is typically done with minimal damage by using dilute AZ400K photoresist developer).  However, 5nm seems to be on the thin side.  Al can form native oxide that is up to 3-4nm thick.  Therefore, I would confirm the answer to Mark's question of whether or not the 5nm Al layer is conductive.  We typically sputter deposit films that are 10-20nm thick for our applications.
>
> Best Regards,
>
> Matt
>
> --
> Matthew T. Moneck, Ph.D.
> Executive Manager, Carnegie Mellon Nanofabrication Facility Electrical and Computer Engineering | Carnegie Mellon University
> 5000 Forbes Ave., Pittsburgh, PA 15213-3890
> T: 412.268.5430
> F: 412.268.3497
> www.ece.cmu.edu
> nanofab.ece.cmu.edu
>
>
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Mark K Mondol
> Sent: Monday, August 21, 2017 5:04 PM
> To: labnetwork at mtl.mit.edu
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
>
> Aju:
>
> 1. Be 100% certain the layer is conductive and connected to ground in the tool.
>
> 2. Every time they write on glass, do the same exposure on Si, if the problem shows up on both Si and glass the issue is not the insulating substrate.
>
> 3. Al etch can damage PMMA; not always in a repeatable way. Does your process include etching the Al (I have found Transene CR-7 chrome etch to be compatible with PMMA and ZEP, so usually use Cr not Al as the conductive layer).
>
> Regards,
>
> Mark K MOndol
>
> --
> Mark K Mondol
> Assistant Director NanoStructures Laboratory And Facility Manager Scanning Electron Beam Lithography Facility Bldg 36  Room 229 www.rle.mit.edu/sebl mondol at mit.edu office - 617-253-9617 cell - 617-224-8756
>
>
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