On Mon, Mar 24, 2008 at 1:16 AM, Owen The  wrote:

> 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.