In this paper, we report vertical etching of poly-ethylene-terephtalate plastic substrates by means of a chemical solvent and in the presence of ultra-violet illumination. Since the PET substrate is not dissolved in solvent without a UV source, only the desired areas with proper opening for UV exposure are removed in a vertical fashion. The etch rate varies between 1 and 8 micrometer per minute, depending on the process conditions. Various structures such as micro-gears and interdigital structures have been realized using this approach. Combining this method with electroplating, the fabrication of micro-motors, micro-valves and optical devices would be possible.
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