Hi,
Thank you all for the advice!

I checked my hotplate, and I think it works ok, because I found that the the
SU-8 layer shrunk a lot and the edge of silicon wafer appeared after
soft-bake, when I used higher soft-bake dose.
The exposure dose should be reduced than that without Omega UV filter, but I
also tried to increase the exposure time by 40%.
The problem has not been solved yet.
Can this problem have something to do with the photoresist itself?
The SU-8 I am using is stored in a small bottle ( sealed but not very well )
instead of the original bottle, and put in the refrigerator (several degree
above zero) for over two months.


On Wed, Oct 22, 2008 at 12:18 AM, GARCIA BLANCO Sonia <
Sonia.Garcia.Blanco@ino.ca> wrote:

> Hi Ruilin,
>
> I had that porblem once and it was due to insufficient soft-bake
> temperature. Check if you have maybe some problem with your hotplate? If
> that is correct, maybe you are under-exposing.