Hi
I am coating SU8 2025 on Si wafer with a target depth of 30um.
I prebake in a hot plate using the ramp up procedure, i.e. 65C for 2
min and 95C for 4 min.
My exposure time is around 100sec and I post-bake the wafer after
exposure in an 80C oven for 90 min. Because I want to do PDMS replica
molding with SU8 masters, I also hard bake the SU8 wafers for 1 hour
in 100C after development for better adhesion of resist.
When I lift-off the PDMS, I see that my thinnest features, ~10um size
features peel off along with the PDMS. Thicker features stay intact.
Please advice if you may have any clue to this problem.
regards
-Abhishek Jain
Arizona State University
Tempe, AZ 85281