AUTOMATED DYNAMIC MODE MULTIDIRECTIONAL UV LITHOGRAPHY FOR COMPLEX 3-D MICROSTRUCTURES
Jungkwun Kim, Mark Allen and Yong-Kyu Yoon
Automated multidirectional UV exposure has been demonstrated using a collimated UV source and a movable stage equipped with two computer controlled motors and a microcontroller for complex three dimensional (3-D) microstructures. The stage is tilted and rotated using independently controlled motors during UV exposure as programmed by the user. Various dynamic operations with the synchronized angular velocities of tilting and rotation have been performed using an SU-8 substrate and a reverse-side exposure scheme. Fabricated structures using the dynamic mode include a vertical reverse triangular slab, a quadruple reverse triangular slab, a cardiac horn, screwed wind vane shapes with double blades and quadruple blades. Ray tracing simulation using mathematical equations has been performed to analytically confirm the shapes of resultant structures.
Keywords: Automated UV exposure, Inclined exposure, multidirectional UV lithography, rotational exposure and screwed wind vane