Hi Mikas,

You can easily clean the mask with hot Piranha bath (110C) for 15 min.
You should use a big quartz beaker and put the soda-lime glass side of
the mask downward to the quartz beaker and the Cr side of the mask
upward. I don't know how robust is your mask so you should test first
by dipping a small corner of the mask to the Piranha bath. I cleaned
our masks (Cr in soda-lime glass) several times with Piranha bath and
there was no problem.

Greetings,

Nam
Dublin City University

On Fri, Mar 26, 2010 at 12:50 AM, mikas remeika
 wrote:
> Dear, Everyone,
>
> I have a photolitography mask, that is starting to accumulate stains
> of SU-8, from the many times it was in contact with samples.  For
> other resists its usually sufficient to rinse the mask in acetone, but
> SU-8 is resistant to most solvents after numerous exposures to UV
> light. I was thinking of trying an oxygen asher. It seems like that
> should be ok, but, just in case, are there are reasons to avoid
> exposing such masks to oxygen plasma? The mask is Soda-Lime coated
> with Cr.
>
> thank you,
> -Mikas