Angled exposure method for pattering on three-dimensional structures

Photolithography on three-dimensional structures is becoming a key process for realizing new micromechanical devices. Patterning on three-dimensional structures using the conventional mask aligner is a difficult task. In this paper, we present an approach for transferring patterns on cavities prepared by anisotropic etching. A new method of angled exposing is introduced for improving the uniformity of the incident-light-power density transmitted into the resist film deposited on the cavities. This method also reduces the number of reflections coming from the sidewalls of the cavities. Polarized light is used for realizing a pattern on the narrow cavities with a high aspect ratio.