Large-area metasurface on CMOS-compatible fabrication platform: driving flat optics from lab to fab

TLDR

Metasurfaces are subwavelength nanostructure layers that enable ultrathin functional devices, and flat‑optics devices have shown high performance in laboratories using electron‑beam lithography, but large‑area metasurfaces fabricated with lithography steppers and scanners are required for low‑cost mass production. This work reviews CMOS‑compatible mass‑manufacturing platforms and functional devices developed to move flat optics from laboratory prototypes to industrial fabrication. The authors present 12‑inch immersion lithography platforms from the Institute of Microelectronics that combine fine critical dimensions with mass production, detailing process flow and demonstrating optical functionalities.

Abstract

Abstract A metasurface is a layer of subwavelength-scale nanostructures that can be used to design functional devices in ultrathin form. Various metasurface-based optical devices – coined as flat optics devices – have been realized with distinction performances in research laboratories using electron beam lithography. To make such devices mass producible at low cost, metasurfaces over a large area have also been defined with lithography steppers and scanners, which are commonly used in semiconductor foundries. This work reviews the metasurface process platforms and functional devices fabricated using complementary metal-oxide-semiconductor-compatible mass manufacturing technologies. Taking both fine critical dimension and mass production into account, the platforms developed at the Institute of Microelectronics (IME), A*STAR using advanced 12-inch immersion lithography have been presented with details, including process flow and demonstrated optical functionalities. These developed platforms aim to drive the flat optics from lab to fab.