Prism-assisted inclined UV lithography for 3D microstructure fabrication

Abstract

A prism-assisted inclined ultraviolet (UV) lithography technique is introduced for the fabrication of three-dimensional (3D) microstructures. Slanted structures with exposure angles ranging from 0° to 60° in SU-8 photoresist have been easily achieved without immersion in the index matching liquid. The fabrication process of multidirectional slanted structures can be simplified by one-step UV exposure using a prism with multidirectional side surfaces. A corner prism and a cone prism have been used in our experiment to demonstrate this concept. Upside-down tripod structures and horn structures have been fabricated in one-step exposures. The effective exposure area as one key parameter of the one-step exposure is analyzed for practical applications. Examples of various 3D microstructures fabricated by this method are presented.