UV Lithography of Ultrathick SU-8 for Microfabrication of High-Aspect-Ratio Microstructures and Applications in Microfluidic and Optical Components

Ultraviolet (UV) lithography of ultrathick photoresist with high-aspectratio, high sidewall quality, and good dimensional control is very important for microelectromechanical systems (MEMS) and micro-optoelectromechanical systems (MOEMS). Although x-ray lithography of methyl methacrylate (PMMA) can meet these requirements, the expensive beamlines are not readily available to many researchers. The high cost of x-ray lithography also made it impractical for many applications. As a cheaper alternative, UV lithography of SU-8 has received wide attention in the last few years. As the obtainable results with UV lithography of SU-8 get better and better, ever more applications have been found for the technology in MEMS and MOEMS.