Then Andrew's interpretation is correct. The SU-8 is being underexposed.
Try increasing your exposure dose to begin with (the datasheets
underestimate the required dose especially for thicker layers).
A filter to cut out <360nm would also be a good idea for such a thick layer.

On Fri, Apr 25, 2008 at 7:39 AM, 郑瑞麟(Ruilin Zheng)
 wrote:
> The profile is more close to the second one.
>  but the upper part seems vertical, and the lower part close to substrate is
>  inclined
>
>  On Thu, Apr 24, 2008 at 9:13 PM, Gareth Jenkins 
>  wrote:
>
>  > Ruilin, could you clarify what profile you are getting?
>  >
>  > Is is wider at the bottom, i.e. something like this:
>  >           ___
>  >           I    I
>  >           I    I
>  >           I    I
>  >          /     \
>  > _____/        \_____
>  >
>  > Or is it more like this:
>  >        _______
>  >         \         /
>  >          \       /
>  >           I      I
>  >           I      I
>  > ______I      I________
>  >
>  > I hope my attempt at ascii art works!
>