Yun-Ching, Have you tried other type of PDMS. For example, here is a paper from Whitesides group titled "Improved Pattern Transfer in Soft Lithography Using Composite Stamps". In this paper, they used hPDMS for very small pattern transfer. It is probably of your interest. Peng Peng Graduate Research Assistant Department of Mechanical Engineering University of Minnesota 111 Church Street S.E., Minneapolis, MN 55455 Tel: (612) 626-2010