Maskless Digital Projection Photochemical Etching

Abstract

We demonstrate a maskless photochemical etching method which is capable of performing one-step etching of multi-level and grayscale structures on semiconductor substrates. This method utilizes a digital projector to focus a light pattern onto the sample where the projected image itself is used to define the etching. This method eliminates the need for expensive grayscale masks or laser writing methods. The etch rate is studied by controlling the wavelength and gray-level intensity of the light. Etching feature resolution of 2.5 μm is demonstrated by etching selected portions of the USAF-1951 target. Micropillars, multi-level cubes, and an Archimedean spiral are etched in a single step to illustrate our unique capabilities.