[mems-talk] Su-8 2050 thickness problem after spin coating.

[Simone Marasso]

Hi All,

We spent much time in order to test the SU-8 2050 to obtain the  
wanted thickness (near 120 microns). We levelled very well our hot  
plate and we tested different times, temperatures and exposure times.  
The major problem occurs after spin coating process. After spinning,  
there are no (or very few) bubbles but we observed non uniform  
layer . When we perform the soft bake SU-8 film tends to  
"spontaneously" form a number of divots or craters that are not  
initially present (after spin-coating). These problems are observed  
with or without the use of OMNICOAT both on silicon surface and Cu  
seed-layer also at different spin velocities.
Has anyone experienced this problem?

thanks

Simone Marasso
Dipartimento di Fisica - Politecnico di Torino
Laboratorio Materiali e Microsistemi (Chivasso - Torino)
simone.marasso at polito.it
http://www.latemar.polito.it/
http://www.polito.it/micronanotech