How about cover the whole chip with SU8?
I don't know where you got the recommendation for the dispense.
I only cared about the spin coating acceleration and speed to make certain
thickness.

Best Regards

Yizhong Wang

University of Pittsburgh, USA> Date: Fri, 22 Feb 2008 14:43:12 -0800> From:
jusanche@cicese.mx> To: mems-talk@memsnet.org> Subject: [mems-talk] su8-2005
question> > hi mems all,> im working with this polymer su8 2005 to make
waveguides of 7um but i> have a big problem, my waffer is made of glass and
dimensions are 2.5cm> x 3.9 cm,> the recommende for a dispense of su8 is 1ml per
inch so i dispense on> wafer 2.5ml of su8 at 1400rpms with minimal acceleration
100rpm/s but> when de procces ends the su8 is not uniform to the wafer surface
(i can> see the su8 not fulfill the wafer) so i tried to dispense more su8 but>
still have the same result, then i tried to make my wafer smaller an> then
dispense 2ml of su8 at the same velocitie and the results were mor> convenient
but still not the entire waffer fulfilled, i hope you can> undestand my question
i know my english is bad :(, if you can help with> some tips for disposing
su8-2005 in the wafer i will be always> gratefull, my best regards> > Juan Jesus
Sanchez Sanchez>