Three-dimensional SU-8 sub-micrometer structuring by electron beam lithography

We demonstrate electron beam lithography on the negative tone electron resist SU-8 to fabricate self-supporting three-dimensional structures in sub-micrometer range. Applying SU-8 thin films spin cast on glass substrates and forming layers of I pm thickness, the structuring is performed in a two step process. First, the SU-8 film is exposed for supporting structures down to the substrate, a second exposure step with accordingly modified parameters leads to elevated structures. Applications as microscale shadow masks for evaporation based deposition processes and microfluidics are discussed. (c) 2008 Elsevier B.V. All rights reserved.