[labnetwork] Ebeam evaporation - arcing between features

[Massey, Travis]

Hi Bob,

Arcing would be mitigated with a charge dissipation layer, like AquaSave, Electra92, thin film of sacrificial aluminum, or equivalent.

However, I'd like to propose an alternative hypothesis for consideration, given the information provided.  The evaporation process is heating the resist (PMMA/co-MMA stack?), facilitating crack formation where stress is concentrated between the two sharp points.

Incomplete arcs don't form, as in the case of your metal lines extending from the two sides of the 8 um gap, so give the cracking hypothesis some consideration.  Resist cracking is much more common!

Travis Massey
Staff Scientist, LLNL

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Geil, Bob
Sent: Tuesday, May 21, 2024 1:49 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Ebeam evaporation - arcing between features

Hello labnetwork,

 I have a user that is fabricating some electrodes and has observed what appears to be arcing between the sharp points of the electrodes. Imagine features like this:  > < where the distance between them is 2um - 8um. The substrate is quartz. Fabrication approach is 1) ebeam lithography 2) ebeam evaporation and 3) lift-off.

After EBL development, the electrode circuit is open, as intended
After evaporation +lift-off, there is a line about few 100nms wide that is shorting the electrodes: >-<
There is not a short between the electrodes with the 8um gap, however, there are some metal lines extending from the two sides:  >-  -<

All of this suggests that arcing is occurring.  Has anyone observed this before and can you suggest ways to get around it?

Thanks,
  Bob


Bob Geil, PhD
Technical Director * CHANL
Dept. of Chemistry * UNC-CH
Chapel Hill, NC




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