[labnetwork] EBeam Lithography on Glass substrates

Thu Aug 24 15:41:39 EDT 2017

We use sputtered Au/Pd exclusively here as a charge dissipation layer and have not seen any adverse effects. Our system for this is a very basic tabletop coater system that runs on 120V and takes maybe 2 minutes of sputtering to get a sufficient coating for our cases. Perhaps power/duration are important to consider.

N. Shane Patrick
Research Engineer, Washington Nanofabrication Facility (WNF) 
National Nanotechnology Coordinated Infrastructure (NNCI)
University of Washington
Fluke Hall 132, Box 352143
(206) 221-1045
patricns at uw.edu <mailto:patricns at uw.edu>
http://www.wnf.washington.edu/ <http://www.wnf.washington.edu/>
> On Aug 24, 2017, at 10:50 AM, Ryan Anderson <ryan at eng.ucsd.edu> wrote:
> 
> Hi all,
> 
> We have also observed adverse effects on PMMA exposure (100kV) after
> sputter coating gold.  Since then we have used thermal evaporation.
> 
> Ryan Anderson
> UC San Diego, Nano3
> 
> 
> -----Original Message-----
> From: labnetwork-bounces at mtl.mit.edu
> [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Fouad Karouta
> Sent: Wednesday, August 23, 2017 4:15 PM
> To: Marc Zuiddam - TNW <M.R.Zuiddam at tudelft.nl>; 'labnetwork at mtl.mit.edu'
> <labnetwork at mtl.mit.edu>
> Subject: Re: [labnetwork] EBeam Lithography on Glass substrates
> 
> 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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