[labnetwork] Photomask sticks to SU8

[Robert Nidetz]

Definitely try the developer first. If it has not been cross linked by the
exposure then it will clean up easy. But if it’s been exposed, you’ll need
piranha solution.

To prevent sticking in the future, make sure your tweezers cannot leave an
impression after the soft bake once the wafer has cooled to room
temperature. If they leave an impression, you’ll need to soft bake more.

Good luck!

Robert Nidetz, PhD (he/him/his)
University of Michigan
LNF User Liaison and Domain Expert
1241 EECS Building
1301 Beal Ave
Ann Arbor, MI 48109
nidetz at umich.edu
734.496.8065
Book an appointment: https://calendly.com/nidetz


On Thu, Feb 12, 2026 at 7:36 PM Phillip Bauer <Phillip.Bauer at formfactor.com>
wrote:

> Hello
>
> I am somewhat new to SU-8 working with Positive resists throughout my
> career. I agree with data sheets are just guideline, for processing.  I saw
> a note from another University to run a 65 deg post bake after the 95 deg
> soft bake.  My question is about mask cleaning.  Is Sulfuric/Peroxide
> (Piranha ~ 60-90C) really needed.  I would think the PGMEA or PGMEA/Acetone
> followed by IPA would be an effective clean.  Just wanted to poll the
> audience.
>
>
>
> <https://www.google.com/maps/search/4350+Innovation+Drive+%0D%0A+%0D%0AFarmers+Branch,+Texas+75244?entry=gmail&source=g>
>
> *Thank you,*
> *Phillip Bauer *
>
> Principal Photolithography Process Engineer
> 4350 Innovation Drive
> <https://www.google.com/maps/search/4350+Innovation+Drive+%0D%0A+%0D%0AFarmers+Branch,+Texas+75244?entry=gmail&source=g>
> Farmers Branch, Texas 75244
> <https://www.google.com/maps/search/4350+Innovation+Drive+%0D%0A+%0D%0AFarmers+Branch,+Texas+75244?entry=gmail&source=g>
>
> *phillip.bauer at formfactor.com <phillip.bauer at formfactor.com>*
>
> M: 682 521 0874
>
>
>
>
>
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