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URN etd-0728110-163058 Statistics This thesis had been viewed 1868 times. Download 186 times. Author Yu-Tung Chen Author's Email Address No Public. Department Materials Engineering Year 2009 Semester 2 Degree Ph.D. Type of Document Doctoral Dissertation Language English Page Count 110 Title Nanofabrication of Fresnel Zone Plates for Transmission X-ray Microscopy by Electron Beam Lithography and Electrodeposition Keyword zone plate electron beam x ray x ray electron beam zone plate Abstract In the research of x-ray microscopy, the fabrication of Fresnel zone plates (FZPs) with high resolution is one of the most difficult and important challenges for focusing hard x-rays. In our study, we utilized e-beam lithography (EBL) and electrodeposition to fabricate gold FZPs with high aspect ratio. We tested the various bake-out conditions and reformed FZPs pattern to make the structure of photo resist after development more stability. In EBL process, the applied dosages in various line widths were refined individually with a detailed evaluation to make the line width more precise. In the development process, the developer was with isopropanol (IPA) and water, without methylisobutylketone (MIBK). The developer with IPA increased the contrast and sensitivity of photo resist in development and made high aspect ratio pattern realizable. In the electrodeposition process, we utilized the localized electrochemical deposition (LECD) method to deposit metal. Electrodeposition with a pulsed current mode and with various current densities produced the desired high aspect ratio nanostructures. In our study, a nanofabrication approach based on EBL and electrodeposition produced FZPs with high aspect ratio (> 30) and high dense structures. Here we showed that FZPs combining 25 nm external zones and the aspect ratio was 20, and 40 nm external zones and the aspect ratio was 30. We validated the spatial resolution with the power spectrum analysis (PSA). FZPs finally bring hard x-ray microscopy beyond the 30 nm Rayleigh spatial resolution level and measureable spatial frequencies down to 16 nm feature size. Advisor Committee Hong-Ming Lin - advisor
Yeukuang Hwu - advisor
Chung-Kwei Lin - co-chair
Liu-ho Chiu - co-chair
She-huang Wu - co-chair
Files Date of Defense 2010-07-12 Date of Submission 2010-07-28