I've patterned SU-8 using exactly the method you described.  As long as the
SU-8 was properly soft-baked and cooled back to room temperature (that bit
is crucial, as SU-8 is tacky when warm) I didn't experience any sticking or
residue on my mylar masks.  I used a Canon PLA-501 4" aligner as the light
source and stacked the wafer/mask as so:

Top: quartz plate
Mylar lithography mask, emulsion side down
SU-8 coated wafer
Bottom: quartz plate

Light entered the stack from the top.  The bottom quartz plate was loaded
into the aligner where the lithography mask typically goes.  The wafer sat
on top of that plate, and the mask was aligned by hand to the wafer and sat
on top of the wafer with the printed side of the mask in contact with the
wafer to improve resolution.  Finally, a quartz plate sat on top of the mask
to keep the mask in contact with the wafer.  No clamps or vacuum chucks
necessary, but I had fairly large features so I could tolerate a slight
misalignment or loss in resolution.  Feel free to contact me if you have any
more questions.

Regards,

Brian C. Stahl
Graduate Student Researcher
UCSB Materials Research Laboratory
[email protected] / [email protected]
Cell: (805) 748-5839
Office: MRL 3117A


On Mon, Mar 16, 2009 at 2:36 AM, 郑瑞麟(Ruilin Zheng) wrote:

> Hello,
>
> I just bought some plastic mask, and I attached them onto a glass plate.
> I want to use these mask for contact lithography on SU-8 layer.
> I am wondering if the SU-8 layer would stick to the plastic mask after
> exposure. Or should I use the opposite side of the mask (i.e. glass plate)
> for contact with SU-8 layer?
>
> But in this way, the lithography won't be the contact one.
> Does anyone has that experience? Please give me some advices.