On Mon, Mar 24, 2008 at 1:16 AM, Owen Thewrote: > 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. Owen, You did not say what is your wafer size but 4 ml of SU8 might be not enough for anything bigger than 4" especially with your long spin time.