Anatoli,
        It may be time to consider a non spin on photo resist.  Various
companies make a stick on resist usually for the printed circuit board
industry.  One from Dupont called Riston comes to mind.  My memory tells me it
is a sheet of Mylar, a sheet of putty like resist 1 mill thick then another
sheet of Mylar.  For low resolution you peel of the bottom sheet of mylar and
stick it on then expose.  For higher resolution you remove the top sheet of
Mylar after you have stuck it down.  Let me know if I can help you further.
Bill Moffat

-----Original Message-----
From: Anatoli Olkhovets [mailto:ao4@lucent.com]
Sent: Monday, July 08, 2002 7:52 AM
To: mems-talk@memsnet.org
Subject: RE: [mems-talk] RE: AZ4562 or other thick photoresist


>These answers provided abundant options in thick photoresist
applications,
>but they all have a thickness limit below 100 microns, so I'm still
curious
>is there any positive resist with the thickness of more than 300um,
which is
>sensitive for UV light and easy to be removed by chemical liquid.

I don't think you can reliably put such thick resist films. The resist
will have to be very viscous, and you will have lots of difficulties with
uniformity and trapped bubbles. You may try applying several coats (spin,
soft bake, repeat). Also I know that in LCD screen industry people use
so-called slot coaters to produce thick uniform films.

Regards,
Anatoli Olkhovets,
Lucent - Bell Labs.
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