hi, shifeng I think you'd better increase the strip time of gold, maybe the residue gold layer prevent the development. And loger develop time will be better, 60s goes well for PMMA in my lab. Did you use the pure IPA to fix the patterns after the development? This process should not be omited. When you use SEM to check the patterns, you shold use the lowest voltage and the shorter exposure the better, otherwise the SEM electrons will turn the resist to black. And depositing 1~2nm gold layer give a big help in SEM observing for the insulating substrate. And you should make sure what you observed is the patterned side, because it is very easy to make mistake for the transparent substrate. Liwei Shang On 25/11/2008, at 3:12 PM, li shifengwrote: Hi, guy I'm trying to write some patterns on glass substrate. Here is my process: Spin coat 500nm PMMA 950 C4, Sputtering 5nm gold EBL exposure Strip gold using TFA gold etcant for 6 second Develop in MIBK : IPA= 1:3 for 30 sec The problem is I cannot find any pattern on the substrate afterwards. What are the possible reasons for that? Anyone have similar experiences on this or has a working recipe to share?