Hello Kamlesh! I have had a similar problem with another resist: it shrunk during the pre-bake step. I thaught about some kind of problem due to the viscosity of the resist. In order to solve the problem, I increased spinning time by ~200% and adjusted the spinning speed to keep the same thickness. Hope this help! Kind regards, Edouard Duriau On Tue, Mar 31, 2009 at 9:54 AM,wrote: > hi all > i am spin coating SU8 2050 on piranha cleaned silicon wafer but > during prebake it is shrinking and coming into the center of the > wafer. What could be the possible cause ? > -- > Kamlesh Pawar