Near-field sub-diffraction photolithography with an elastomeric photomask

Sangyoon Paik,Su Seok Choi,Hyun Jae Kim,Jaejun Lee,Shinill Kang,Jekwan Lee,Kwang Yong Jeong ,Heon Jin Choi ,Jinwoo Cheon,Hyungsik Roger Moon ,Hyunyong Choi,Jae Hyun Lee ,Hong Gyu Park ,Joonho Moon ,Jae‐Min Myoung ,Gwangmook Kim,I Sak Lee ,Dana Jin,Kyunghi Chang ,Wooyoung Lee,Soon-Shin Jung ,Miso Kim,Sehwan Chang,Sooun Lee,Wooyoung Shim

doi:10.1038/s41467-020-14439-1

Abstract

Photolithography is the prevalent microfabrication technology. It needs to meet resolution and yield demands at a cost that makes it economically viable. However, conventional far-field photolithography has reached the diffraction limit, which imposes complex optics and short-wavelength beam source to achieve high resolution at the expense of cost efficiency. Here, we present a cost-effective near-field optical printing approach that uses metal patterns embedded in a flexible elastomer photomask with mechanical robustness. This technique generates sub-diffraction patterns that are smaller than 1/10th of the wavelength of the incoming light. It can be integrated into existing hardware and standard mercury lamp, and used for a variety of surfaces, such as curved, rough and defect surfaces. This method offers a higher resolution than common light-based printing systems, while enabling parallel-writing. We anticipate that it will be widely used in academic and industrial productions.

Highlights

IntroductionWe present a cost-effective near-field optical printing approach that uses metal patterns embedded in a flexible elastomer photomask with mechanical robustness
We found that our fabrication protocol yielded an array of uniform and continuous Cr patterns embedded in PDMS
We demonstrate that our technique is a simple and powerful lithographic approach, which uses a photomask composed of chromium patterns embedded in elastomeric mask plate

Summary

Introduction

We present a cost-effective near-field optical printing approach that uses metal patterns embedded in a flexible elastomer photomask with mechanical robustness This technique generates sub-diffraction patterns that are smaller than 1/10th of the wavelength of the incoming light. The state-of-art photolithography in the industry adopts projection printing, which requires optical elements to focus the mask image onto the wafer surface to achieve a high resolution It offers low defect density, high registration, high performance, and sub-10 nm node resolution by using extreme ultraviolet (EUV)[1,2]. Elastomeric masks utilize a phase shift originated from the structure of elastomer and provide high resolution and mechanical robustness[8,9] They lack the capability to pattern arbitrary shapes, which limits them from being a versatile lithographic tool. The combination of near-field capability for sub-diffraction pattern generation with elastomeric characteristic of the mask provides a simple, flexible, and low-cost lithographic tool that has the potential to replace EUV lithography

Methods

Results

Conclusion