Fabricating Elastomeric Photomask with Nanosized-Metal Patterns for Near-Field Contact Printing

Paik, Sangyoon; Kim, Gwangmook; Seo, Dongchul; Shim, Wooyoung

doi:.59.2.142

Korean Journal of Metals and Materials > Volume 59(2); > Article

Research Paper

doi: https://doi.org/10.3365/KJMM.2021.59.2.142

Fabricating Elastomeric Photomask with Nanosized-Metal Patterns for Near-Field Contact Printing

Sangyoon Paik^1,2,3, Gwangmook Kim^1,2, Dongchul Seo^1,2, Wooyoung Shim^1,2

¹Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
²Center for Multi-Dimensional Materials, Yonsei University, Seoul 03722, Republic of Korea
³LCD TV Panel design team 2, LG Display Co., Ltd. Gyeonggi 10845, Republic of Korea

Correspondence

Wooyoung Shim ,Tel: +82-2-2123-2857, Email: wshim@yonsei.ac.kr

Received: 23 September 2020; Accepted: 13 December 2020. Published online: 27 January 2021.
*Sangyoon Paik and Gwangmook Kim contributed equally to this work.

ABSTRACT

When an elastomeric photomask is used for near-field contact printing, the high deformability of the elastomer mask plate enables gap-free full contact with the substrate, minimizing the effect of diffraction. This image-transfer technique provides sub-50 nm resolution and depth-of-focus-free lithographic capability with cost-efficient equipment. However, the method’s application is limited due to the lack of a wellestablished protocol for fabricating a nanoscale mask pattern on an elastomeric substrate, which remains a major technical challenge in the field of near-field contact printing. In this study, we present a reliable protocol for fabricating a metal-embedded polydimethylsiloxane (PDMS) photomask. Our fabrication protocol uses conventional nanofabrication processes to fabricate nanosized chromium mask patterns and then transfers the chromium patterns to an elastomeric mask plate using a sacrificial Ni layer. Our protocol provides a high flexibility mask pattern design, and highly stable metal patterns during transferring process. By careful optimizing the experimental parameters, we determined a perfect pattern transfer ratio, which avoided any mechanical failure of the metal pattern, such as debonding or wrinkling. We then fabricated a PDMS photomask and confirmed its nanoscale patterning resolution, with the smallest feature 51 nm in width under a 400-nm light source. We anticipate that our fabrication protocol will enable the application of cost-efficient and high-resolution near-field photolithography.

Keywords: near-field photolithography, elastomeric photomask, transferring process