A novel micro-machining method for the fabrication of thick-film SU-8 embedded micro-channels

In this paper, a novel method to realize embedded micro-channels is presented. The presented technology is based on a direct write technique using proton beams to pattern thick-film SU-8. This proton micro-machining method allows the production of high aspect ratio and complex three-dimensional micro-structures in polymers with aspect ratios of over 100 and 20 using poly(methylmethacrylate) (PMMA) and SU-8 respectively. As the SU-8 is used as a structural material, its mechanical properties have to be characterized. For a start, the Young's modulus of the proton beam exposed SU-8 is determined using a stylus-type load-deflection method. The second part of this paper describes the underlying theory and method used by the author to determine the Young's modulus of the proton beam exposed SU-8. Measurements of the SU-8 micro-structures show that the Young's modulus is dependent on the proton beam exposure dose. An exposure dose of 9.5 nC mm-2 results in an average Young's modulus value of 4.254 GPa.

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