Dear Debashis Maji,

I had the same problems weeks before.

I suggest you reduce the space between the SU-8 and mask which means it is not a
good closed contact.

Maybe it will work. In addition please do not reverse the mask sides. There is
only one side which is applied the material if you use the film mask.

Good luck
Regards


At 2011-04-19 23:14:31，"DEBASHIS MAJI"  wrote:

>Dear All,
>
>I am trying to make SU8-50  square wells (height- 40um) to be used as masters
>for PDMS moulds. The square dimensions vary from 1mm x 1mm to 2.5 mm
>x 2.5 mm. When I finally develop these wells after exposure and post bake, I
>find that almost all of them have undeveloped SU8 remaining along the a
>single ( or sometimes two adjacent ) edge which is same for all the wells
>and gets repeated also. I had developed it for the recommended time i.e. 6
>min for 40 um height well but even after developing for longer time it still
>stays their. Is it because of over exposure? if so then why is it that only
>a particular edge (of all the wells) has the residual SU8 due overexposure
>whereas the other edges, particularly the opposite one is absolutely fine?
>kindly help.
>
>I would also like to ask whether the UV exposure dose for SU8 on SiO2 is
>less than that of SU8 on Si and adhesion of SU8 is better over Sio2 or Si?
>I shall be highly obliged if anyone can kindly help me.
>
>Thanks in advance.
>
>Debashis Maji