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?

regards
Vaibhav Mathur
Photonics Center
Univ of Massachusetts,Lowell