# Asymmetric Diffusion Metasurface-Based Lensless Monitoring and Uniform Illumination Systems for Optical Lithography

## TL;DR

This paper introduces a new lensless illumination system using metasurfaces and algorithms to improve optical lithography with uniform light and real-time monitoring.

## Contribution

The novel use of asymmetric diffusion metasurfaces and intelligent algorithms for lensless lithographic illumination.

## Key findings

- The system achieves UV illumination nonuniformity below 3% without conventional lenses.
- Real-time LED performance monitoring enables adaptive exposure configurations.
- The platform successfully exposes patterns across various feature sizes.

## Abstract

The long-standing trade-off between illumination performance (such as uniformity) and optical system complexity has hindered the development of compact lithographic tools. Here, we overcome this limitation by introducing a metasurface-enabled lensless illumination system that seamlessly combines light homogenization and monitoring capabilities. Using an asymmetric diffusion metasurface integrated with intelligent optimization algorithms, we achieve precise light field control and self-adaptive feedback without relying on conventional lens assemblies. When deployed on a self-developed large-field lithography platform, the system demonstrates uniform ultraviolet illumination with nonuniformity below 3% and successfully exposes patterns across a range of feature sizes. A gray-level to power-level mapping algorithm enables real-time assessment of light-emitting diode performance, providing diagnostic alerts and adaptively reconfigurable exposure configurations to circumvent defective emitters. This synergy between metasurface optics and algorithmic intelligence establishes a new paradigm for compact, low-cost, and scalable lithographic illumination, offering a pathway toward next-generation intelligent manufacturing systems.