Hai all, Thanks for the help. but i tried all those and the recipe i am using is: 1)spinning at 500 rpm with ramp=500rpm/sec to spread out the resist to the edge. 2)then ramping the speed to 1500rpm with ramp=500rpm/sec to obtain 12micron thick resist. Then i even tried cleaning the wafers using pirahna before spinning resist. So can anyone suggest me what I can do more. sincerely Sandhya Reddy Research assistant Boise state university Ph.No. 208-426-5639 --------------------------------- Do you Yahoo!? Free online calendar with sync to Outlook(TM).