[labnetwork] Heidelberg MLA150 SU-8 Exposure Dose

[Hollingshead, Dave]

Dear Labnetwork,

We have found that exposure of SU-8 on our MLA150 tool (using the 375nm laser) seems to require very high doses. Even thin ~500nm thick films (using SU-8 2000.5) have required doses on the order of 1200mJ/cm2 to fully expose. This is 15-20x the recommended dosage from both the datasheet and what we estimate is the exposure dose used on our filtered contact aligners. Thicker films follow the same trend, but not necessarily in a linear fashion (5µm films require ~2000mJ/cm2).

I am sure the bump from 365nm to 375nm plays a role, but the magnitude of the change seems excessive. FWIW, our other negative resists (eg. nLOF2020) seem to expose properly at reasonable doses.

Has anyone else experienced this? Does anyone have an explanation or any processing suggestions for using SU-8 with an MLA?

Thanks,
-Dave
Dave Hollingshead
Manager, Research Operations

The Ohio State University
Nanotech West Labs
Suite 100, 1381 Kinnear Rd, Columbus, OH 43212
614.292.1355 Office
hollingshead.19 at osu.edu<mailto:hollingshead.19 at osu.edu> / nanotech.osu.edu<http://nanotech.osu.edu>

Pronouns: he/him/his

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