Mask-Based Microsphere Photolithography

Microsphere Photolithography (MPL) uses a self-assembled array of transparent microspheres to focus incident ultraviolet radiation and produce an array of photonic jets in photoresist. Typically, the microspheres are self-assembled directly on the photoresist layer and are removed after exposure during development. Reusing the microsphere array reduces the expense of the process. A mask is formed by transferring the self-assembled microsphere array to a transparent tape. This can be used for multiple exposures when pressed into contact with the photoresist. This paper demonstrates the use of this process to pattern infrared metasurface absorbers and discusses the effects of the mask-based MPL process on the metasurface performance.