*Smooth side wall profile Using AZ 5209*

Hi,

I am trying to develop a smooth side-wall profile (of step height ~ 2um)
using AZ 5209 E positive resist.
I have tried for different exposure and development times, and have obtained
bumps along the sidewall.
Could anyone suggest me, how to obtain a smooth side wall profile without
curved edges.

Thanks in advance.

Regards,
RK