Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

- Two novel fabrication process to fabricate suspended layers with two UV exposures (365 nm and 405 nm).
- The processes is compared with 365 nm process in terms of control of suspended layer thickness and resolution limits.
- A change in wavelength and the introduction of an additional spin coating step improved processing flexibility.

In this work we present an easy, fast, reliable and low cost microfabrication technique for fabricating suspended microstructures of epoxy based photoresists with UV photolithography. Two different fabrication processes with epoxy based resins (SU-8 and mr-DWL) using UV exposures at wavelengths of 313 nm and 405 nm were optimized and compared in terms of structural stability, control of suspended layer thickness and resolution limits. A novel fabrication process combining the two photoresists SU-8 and mr-DWL with two UV exposures at 365 nm and 405 nm respectively provided a wider processing window for definition of well-defined suspended microstructures with lateral dimensions down to 5 μm when compared to 313 nm or 365 nm UV photolithography processes.

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