The 2000 series of SU-8 are formulated in cyclopentanone. If you want
to dilute your stock yourself, use cyclopentanone, not IPA. I hope you
have a mechanical shaker, or very strong arms.

Alternatively, just buy the right formulation from Microchem, at the
correct concentration and viscosity for the thickness you want. The
series is numbered so that the last digits give the relative viscosity
(i.e., SU-8 2100 is useful in the 100 micron thick range, and is more
viscous than SU-8 25, which is useful in the 25 micron thick range).
I'd highly recommend you just buy the concentration you need instead
of trying to dilute it yourself.

- Kevin

On Wed, Apr 20, 2011 at 6:09 AM, 첸로  wrote:
> Dear everyone,
>
> I am using SU-8 2075 in photolithography. I want to get a thin film after spin
coating so i intend to use IPA to dilute su-8, but it does not work. Has anybody
encountered this problem?  How do you dilute the su-8?
>
> Any suggestion will be highly appreciated.
>
> Thanks in advance.
> Regards