Hi all, I've been having some trouble with my SU8 Processing.
Currently I'm using SU8 2100. I'm trying to get a postbaked thickness
of 260um, but I've been consistently getting half the quoted thickness
(130um in this case) for any given speed.

Here's my processing steps:

1) Wafer prep
2) Dispense 4ml of SU8 on a slowly spinning wafer (to center the blob)
3) Ramp to the set speed (in this case 1000 RPM), hold for a few minutes and
then stop
4) Rest in a covered petri dish on top of a small filter with a little acetone
(to even out the surface)
5) Softbake (ramping to set temps)
6) Expose and postbake (ramps to temps again)
7) Develop in acetone, rinse with isopropanol and water

Not sure what I'm missing, but I've done this process with other
grades of SU8 and have always seen 50% of the quoted film thickness.

Any help is greatly appreciated

-Owen