This paper presents a systematic study on a novel 3D (three-dimensional) UV (ultraviolet) lithography apparatus for thick photoresist and a UV lithography process simulation for 3D microstructuring. In order to realize a wide variety of 3D microstructures, the developed proximity 3D UV lithography apparatus adopts the ‘moving mask lithography’ concept which was originally proposed by the authors for deep x-ray lithography. Furthermore, the authors propose a new practical photoresist profile simulation approach adopting the ‘fast marching method’ to consider the photoresist dissolution vector in the development process. A series of moving mask UV lithography experiments using a positive-tone photoresist (50 µm thickness) successfully confirmed (1) the capability of the moving mask UV exposure technique for 3D microstructuring and (2) the validity of the proposed photoresist profile simulation.

This paper presents a systematic study on "Moving-mask UV lithography" for 3-D (threedimensional) microstructuring of positive-and negative-tone thick photoresist and a dedicated UV lithography process simulation. As an application of the moving-mask UV lithography, we propose a novel method to fabricate embedded microfluidic structures using SU-8. Furthermore, we propose a new practical photoresist profile simulation approach adopting the "Fast Marching Method" to consider the photoresist dissolution vector in the development process. Through a series of moving-mask UV lithography experiments, (1) the capability of the moving-mask UV lithography for 3-D microstructuring, and (2) the validity of the proposed photoresist profile simulation, were successfully confirmed.

No abstract