Fabrication of 15 nm curvature radius polymer tip probe on an optical fiber via two-photon polymerization and O2-plasma ashing

• Published in: Current applied physics 2013, 13(9), , pp.2064-2069
• Main Authors: Jung, Byung Je, Kong, Hong Jin, Cho, Yong-Hoon, Park, Chung Hyun, Kim, Min Kwan, Jeon, Byoung Goo, Yang, Dong-Yol, Lee, Kwang-Sup
• Format: Article
• Language: English
• Subjects: Apexes; Atomic force microscopy; Curvature; gold; image analysis; Imaging; Mathematical analysis; Nanofabrication; O2-plasma ashing; Optical fibers; physics; Polymer tip; polymerization; polystyrenes; Radius of curvature; Reduction; Scanning; Two-photon photopolymerization; 물리학
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2013.09.011

Polymer tips with 15 nm curvature radius apexes that are capable of scanning the surface of a sample have been fabricated on the surface of an optical fiber using two-photon photopolymerization (TPP) and O2-plasma ashing with a SCR500 resin. First, the parent conical polymer tip with a 125 nm curvature radius apex was fabricated via TPP using a continuous scanning method and the accumulation of circular layers. Next, the tip was sharpened using an O2-plasma ashing process with high reproducibility. As a result, the apex radius of curvature had a maximum reduction to 15 nm. In order to evaluate the performance of the 15 nm curvature radius polymer tip, a 30 nm thick gold layer with holes of 250 nm radius and a single layer of polystyrene beads with a 350 nm radius were imaged using a tuning-fork-based atomic force microscope. The topographic images obtained by the 15 nm polymer tip were improved in width and depth compared with those obtained by the 125 nm polymer tip due to the reduction of the imaging artifacts. This method can also be commonly used to reduce the radius of curvature of the polymer tip in order to achieve more accurate imaging. •The polymer tips with the smallest size ever reported were fabricated for AFM.•The two-photon photopolymerization and O2-plasma ashing were used.•The topographic images were improved due to the reduction of the imaging artifacts.•The two-step method can be commonly used to reduce the curvatures of polymer tips.