Thanks for all of your suggestions. As for the difference between Si and glass, I had no such problem when dealing with Si substrate. Somebody mentioned using a piece of black paper beneath the coverglass, but I never tried. I definitely need to try you guys' suggestion one by one. Best, Liu Yu On 12/28/05, Zeta Tak For YUwrote: > HI Fellows, > > BTW: you are using glass, could the diffraction and reflection effect be > stronger and cause surrounding SU-8 cross-linked? possibly... can you > try the process with a Si and compare? thanks. > > zeta yu >