Hi Vaibhav,

Andrew is right, the best thing would be change the
SU-8 blend, choosing the one that lets you get the
thickness you want (SU-8 2005 would be nice). You can
try eliminate some solvent from your blend by warming
it, but you should control viscosity and keep on mind
that some polymerization could happen by heating.

 Regards
 Eowin
--- vaibhav mathur  skrev:

> hi all,
>
> I use microchem SU-8 2. At 2000 rpm I achieve
> 2micron thickness. Now I want
>  to increase the height to 5-6 microns. how do i do
> this??
>
> 1) when I spin coat at 1000 rpm I get about 5
> microns, the height is
> inconsistent though, and i get very bad edge bead.
> can someone suggest
> how to do this properly
>
> 2) also, if I do double spin coating, I should get 4
> microns, right? but I
> get only about 2.4 microns, an increase of just 20
> percent, I dont understand.
> Does someone have a recipe for double spin coating
> of SU-8?