Hi,
I use SU-8--2025 to make the mold master. The mold is comprised of two
layers, first one is the base which is a rectangular channel(2.5mm x
50 mm x 60um). The mask that I use is a film which is stuck to the
glass plate. Then I spin the second coating of SU-8 after the PEB of
the first layer , but without developing the photoresist. The second
layer is comparable to an array of small rectangular walls ( 2.5mm x
50um x 30um) and they are present all along the first layer. The walls
are separated by 50um. After SEB and exposure, I do the PEB, which is
then followed by developing.
I plasma treat the silicon wafer before spinning the first layer and I
plasma treat the SU-8 of first layer before spin coating the second
layer. The mold looks good under the microscope. The problem is part
of the small structures comes with the PDMS, when I peel it after
baking the PDMS.
Is there some sort of a solvent that I can coat the mold with for easy
removal of PDMS or is there something that I can do in the mold
fabrication process itself to avoid this problem.
Thanks a bunch in advance. Any help is greatly appreciated as I am
kind of stuck.
Cheers,
Vishwa