Just spin on the whole wafer then cut out the central even area for use.

Or you need special spin tools with bead removal.

On Wed, Dec 1, 2010 at 11:30 AM, Nirmal punjabi wrote:

> Hi,
>
> I need a thickness of around 400um of SU-8, i am spin coating SU-8 2100 at
> 800rpm for 60 sec.
>
> But the final structure formed has uneven surface.
>
> Can anyone help me on this matter?
>
> Thank you.
>
> Nirmal.

--
Lin, Xiaohui
Ph.D. Program in Electrical and Computer Engineering
Nanophotonics and Optical Interconnects Group
Microelectronics Research Center
The University of Texas at Austin
E-mail: xiaohui.lin@mail.utexas.edu
Office: (512) 471-4349