利用電子束微影及電化學沈積製作菲涅耳波帶片及其於穿隧式X光顯微鏡上之應用

Nanofabrication of Fresnel Zone Plates for Transmission X-ray Microscopy by Electron Beam Lithography and Electrodeposition

陳語同(Yu-Tung Chen)

指導教授 ： 林鴻明 ； 胡宇光

大同大學/工程學院/材料工程學系所/博士(2010年)

摘要

在x光顯微鏡的研究中，製作能聚焦硬x光並具有高解析度的菲涅耳波帶片是一件很困難且重要的挑戰。在實驗中，我們結合了電子束微影及電化學沈積的方式，製作出以金為材料的高深寬比菲涅耳波帶片。我們先測試光阻適當的烘烤條件，並改良菲涅耳波帶片的圖形設計，可使得顯影後的光阻有較佳的穩定性。在電子束微影的步驟中，分別去調整在不同線寬所適用的曝光劑量以達到曝光後的精確線寬。在顯影過程中，我們不使用甲基異丙酮作為光阻的顯影夜，而是使用異丙醇與水混合的顯影液，使得光阻在顯影時有較佳的對比性及感光度，讓高深寬比的結構可以實現。在電化學沈積中，我們利用局部電化學沈積的實驗架構沈積金屬，電鍍參數是使用脈動式的電流搭配不同的電流密度來製作出具有高深寬比的奈米金屬結構。在我們的研究中，我們能以電子束微影及電化學沈積方式可製作出具有高深寬比 (> 30) 且高密集度結構的菲涅耳波帶片。這裡我們展示出具有25奈米的最小線寬及深寬比20，和40 奈米的最小線寬及深寬比到達30的菲涅耳波帶片。最後我們利用波譜分析方式去驗證菲涅耳波帶片的空間解析度。由波譜分析可驗證，菲涅耳波帶片可使硬x光微顯鏡具有小於30奈米的萊利空間解析度且可量測到空間頻率小於16奈米尺寸。

關鍵字

x光 ； 電子束 ； 波帶片

並列摘要

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.

並列關鍵字

x ray ； electron beam ； zone plate

參考文獻

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