Thank you all for your generous helps. After the expose, PEB and developing, should I do some further bake ? Since I the SU-8 100 to stay as the mechanical structure and it needs to have some robustness. Thanks J.J. Wang Florian Herraultwrote: Is it 250F or 250C ? If it is celcius, it is way too high ! use a leveled hotplate and put your sample on it at RT. ramp it up to 95C for about 4-5hrs and ramp it down ! wait for 1 hr, expose, postbake from 25 to 95 for 1 hr and ramp it down again. wait 3hrs and develop 200 um thick is not that thick. you should not have any problem with it ! florian