[labnetwork] EBeam Lithography on Glass substrates

Thu Aug 24 13:50:22 EDT 2017

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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