3D microfabrication with inclined/rotated UV lithography

This paper presents a novel microfabrication technology of three-dimensional (3D) microstructures with inclined/rotated UV lithography using negative thick photoresist, SU-8. In exposure process, a photomask and a SU-8 coated substrate are fixed together, and tilted or tilted and rotated to a UV source. The reflected UV at the interface between the resist and the substrate is also exploited as well as the incident UV. With the 3D microfabrication technology, various 3D microstructures are easily fabricated such as oblique cylinders, embedded channels, bridges, V-grooves, truncated cones, and so on. The angles between fabricated structures and normal lines are 19.5degrees, when the incident angle of UV in air is 32degrees. Thus, the refractive index of SU-8 and the maximum refractive angle at the interface between SU-8 and air are expected about 1.6 and 39degrees, respectively. (C) 2003 Elsevier B.V. All rights reserved.