[labnetwork] e-beam evaporation after e-beam lithography

[Nathan Nelson - Fitzpatrick]

Hi Pradnya,

I have experienced this problem in the past and in fact it was discussed in good detail on Labnetwork earlier this year in the thread “Blistering of metal film stack on PMMA”.

https://mtl.mit.edu/pipermail/labnetwork/2019-February/thread.html#start

Long story short, it could be due to excessive sample temperature or bombardment with electrons (scattered from your E-gun) or X-rays.  There are a number of solutions to this problem such as:


  *   Increasing source to sample distance
  *   Avoiding carbon contamination in the crucible (avoiding “Fabmate” crucible liners for Gold)
  *   Deflecting electrons away from the sample using electrostatic or magnetic methods
  *   Increasing deposition rate to reduce time sample is being bombarded by electrons

Best of luck!

-Nathan

--
Nathan Nelson-Fitzpatrick  PhD
Nanofabrication Process & Characterization Engineering Manager
Quantum-Nano Fabrication and Characterization Facility (QNFCF)
Office of Research
University of Waterloo
200 University Avenue West, Waterloo, ON  N2L 3G1
P: 519-888-4567 ext. 31796
C: 226-218-3206
https://fab.qnc.uwaterloo.ca

[/Users/nnelsonf/Desktop/university-of-waterloo-logo-esig.png]


From: <labnetwork-bounces at mtl.mit.edu> on behalf of Pradnya Chabbi <pradnya.chabbi at gmail.com>
Date: Friday, November 15, 2019 at 8:00 AM
To: "labnetwork at mtl.mit.edu" <labnetwork at mtl.mit.edu>
Subject: [labnetwork] e-beam evaporation after e-beam lithography

Dear all,
We are trying to deposit Ni-10nm and Au-50nm on top patterned EL9-PMMA e-beam lithography sample for liftoff. But the deposited film is grainy and agglomerated.
This problem does not occur with photolitithography resists or for any other depositions. It only arises in case of samples that have undergone e-beam lithography and have patterned e-beam resist on top. We are unable to troubleshoot the root cause. Attaching an image below

Has anyone else faced similar problems?
Did you manage to troubleshoot the issue and find a solution?
Kindly let us know.


[image.png]

--
Thanks & regards
Pradnya
-------------------------------------------
Process Technologist,
CEN, IITBNF, Electrical Engg Dept, Annexe,
IIT Bombay, Mumbai, Powai- 400076
Contact - 09420391187(M)
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