[mems-talk] SU8 Cracking

[oygm]

Hi, guys
 
I did more experiment on su8 coating these days. It seems in my situation, too dry su8 leads to the cracks. As I mentioned before the su8 which I used is expired. Somebody said that the expired su8 will be dehydrated. Hence I decreased the prebake and softbake time. Then most of the cracks vanished after developing in 4mins. The baked dose I used was:  softbake at 50c 2mins, @90c for 4mins, move wafer out of hotplate and let it cool down to RT.
PEB at 75c for 10mins, let wafer cool down with hotplate.
 
Sonic