Two step lithography와 나노 실리카 코팅을 이용한 초발수 필름 제작
Fabrication of Superhydrophobic Film with Uniform Structures Using Two Step Lithography and Nanosilica Coating
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We propose a two-step lithography process to minimize edge-bead issues caused by thick photoresist (PR) coating. In the con- ventional PR process, the edge bead can be efficiently removed by applying an edge-bead removal (EBR) process while rotating thesilicon wafer at a high speed. However, applying conventional EBR to the production of desired PR mold with unique negative patternscannot be used because a lower rpm of spin coating and a lower temperature in the soft bake process are required. To overcome this problem, a two-step lithography process was developed in this study and applied to the fabrication of a polydimethylsiloxane (PDMS)film having super-hydrophobic characteristics. Following UV exposure with a first photomask, the exposed part of the silicon wafer wasselectively removed by applying a PR developer while rotating at a low rpm. Then, unique PR mold structures were prepared by employing an additional under-exposure process with a second mask, and the mold patterns were transferred to the PDMS. Resultsshowed that the fabricated PDMS film based on the two-step lithography process reduced the height difference from 23% to 5%. Inaddition, the water contact angle was greatly improved by spraying of hydrophobic nanosilica on the dual-scaled PDMS surface.
Abstract
We propose a two-step lithography process to minimize edge-bead issues caused by thick photoresist (PR) coating. In the con- ventional PR process, the edge bead can be efficiently removed by applying an edge-bead removal (EBR) process while rotating thesilicon wafer at a high speed. However, applying conventional EBR to the production of desired PR mold with unique negative patternscannot be used because a lower rpm of spin coating and a lower temperature in the soft bake process are required. To overcome this problem, a two-step lithography process was developed in this study and applied to the fabrication of a polydimethylsiloxane (PDMS)film having super-hydrophobic characteristics. Following UV exposure with a first photomask, the exposed part of the silicon wafer wasselectively removed by applying a PR developer while rotating at a low rpm. Then, unique PR mold structures were prepared by employing an additional under-exposure process with a second mask, and the mold patterns were transferred to the PDMS. Resultsshowed that the fabricated PDMS film based on the two-step lithography process reduced the height difference from 23% to 5%. Inaddition, the water contact angle was greatly improved by spraying of hydrophobic nanosilica on the dual-scaled PDMS surface.
참고문헌 (13)
- B. Bhushan, "Natural and biomimetic artificial surfaces for superhydrophobicity, self-cleaning, low adhesion, and drag reduction", Progr. Mater. Sci, 56(1), pp.1~108 (2010)
- T. -G. Cha, "Nanoscale patterning of microtextured surfaces to control superhydrophobic robustness", Langmuir, 26(11), pp.8319~8326 (2010)
- S. M. Lee, "The Effect of the Surface Wettability of Nanoprotrusions Formed on Networktype, Microstructures", J. Micromech. Microeng, 18(12), pp.125007~125014 (2008)
- T. Baldacchini, "Superhydrophobic Surfaces Prepared by Microstructuring of Silicon Using a Femtosecond Laser", Langmuir, 22(11), pp.4917~4919 (2006)
- 김도형, "표면 젖음성을 이용한 물", 오일 분리막 제작, 2016, pp.25(3), 213~217[DOI]
- L. Pan, "Facile preparation of superhydrophobic copper surface by HNO3 etching technique with the assistance of CTAB and ultrasonication", Appl. Surf. Sci, 15(5), pp.1707~1711 (2010)
- R. Liao, "Fabrication of superhydrophobic surface on aluminum by continuous chemical etching and its anti-icing property", Appl. Surf. Sci, 317(30), pp.701~709 (2014)
- S. A. Mahadik, "Transparent Superhydrophobic silica coatings on glass by sol-gel method", Appl. Surf. Sci, 257(2), pp.333~339 (2010)
- Y. -S. Yoon, "Fabrication of Optically Transparent PDMS Artificial Lotus Leaf Film Using Underexposed and Underbaked Photoresist Mold", J. Microelectromech. Syst, 22(5), pp.1073~1080 (2013)
- J. -S. Park, "Optically transparent super-hydrophobic thin film fabricated by reusable polyurethane-acrylate(PUA)mold", J. Micromech. Microeng, 28(2), pp.25004~25012 (2018)
- H. Lee, "A new fabrication process for uniform SU-8 thick photoresist structures by simultaneously removing edge bead and air bubbles", J. Micromech. Microeng, 21(12), pp.125006~125014 (2011)
- R. D. Deegan, "Capillary flow as the cause of ring stains from dried liquid drops", Nature, 389(6653), pp.827~289 (1997)
- Hyeoung Woo Park, "Simple and Cost-Effective Method for Edge Bead Removal by Using a Taping Method", Journal of the Korean Physical Society, 73(10), pp.1473~1478 (2018), 한국물리학회