李世光臺灣大學：工程科學及海洋工程學研究所袁 琪 葦YUAN, CHI-WEICHI-WEIYUAN2007-11-262018-06-282007-11-262018-06-282005http://ntur.lib.ntu.edu.tw//handle/246246/51053由於奈米科技的快速發展以及半導體製程的設計線寬逐年減小，量測定位技術之需求大增，其精度要求也漸增至奈米等級。根據ITRS(International Technology Roadmap of Semiconductor)的roadmap所述，2004年對線寬之要求由2003年的107nm縮減為90nm，對於疊對(overlap)精確度的要求也從3.5nm降為3.2nm。在線寬從100奈米朝向10奈米發展的過程中，傳統微影術 (lithography)面臨極大的難題，在光源與步進掃描的系統由於對應光波長之繞射極限問題，在成功突破100奈米之後，由於153奈米之光源仍不夠穩定，50奈米以下的製程仍有極大的問題待克服。而奈米壓印(nano-imprint)則提供了一條已證明CD(critical dimension)可達到10奈米以下的另一路徑。但是無論是步進掃描的系統或是奈米壓印的方式，其相關定位技術仍必須一起進步以實現10奈米的尺寸之下之製程。 論文主體在於設計並製作奈米壓印系統平台以及定位子系統。壓印系統之對位重點有二：其一為晶圓面與母模之平行度，其中將採用氣壓方式使之自動平行校準；其二為壓印母模與晶圓本身之二軸精密對位，論文將使用類似於目前掃描步進機的對位控制方式，使用兩段式控制 (dual-stage control)，第一階段使用下層的位移平台配合傳統的對位記號與白光顯微術做微米等級的粗定位，第二階段的對位系統採用光學干涉儀與影像檢測法並行之方式配合壓電致動器作奈米等級的精準對位。其中光學干涉儀分為近場模式量測以及遠場量測模式。遠場量測模式採用干涉術，配合壓印模與晶圓上的光柵尺，以繞射式光學尺的方式呈現；近場量測模式採用光柵耦合原理，以正負一階光強變化的曲線作為檢測的依據。而影像檢測法採用對位光柵偏移所造成光學影像偏差的方式，以CCD作影像耦合運算，藉由數值模擬計算之方式突破繞射極限。最終目的為開發一套具有奈米等級多道製程對位能力的奈米壓印系統。As semiconductor vendors strive to reduce the feature sizes of integrated circuits, the need for next-generation lithography (NGL) tools increases. The escalating cost of these tools for conventional optical and extreme ultraviolet (EUV) lithography is driven in part by the need for complex optical sources and optics. The cost for a single NGL tool could exceed $50 million in the next few years, a prohibitive figure for many companies and laboratories. Nanoimprint offers a low-cost alternative method for printing sub-100 nm features with great potential accuracy, high resolution, and reductivity. Overlay with alignment precision in the range of the resolution is mandatory for a large number of applications. Specific process details of UV nanoimprint lithography (UV-NIL) offer three main advantages to reach the overlay accuracy required. First, the transparent imprint molds allow one to adopt alignment techniques developed for optical or x-ray lithography. Second, the absence of thermal cycles in UV-NIL enhances the overlay accuracy principally and is favorable for optical interferometric techniques. Third, prior to UV curing the imprint resist remains in a state of low viscosity, allowing fine alignment in contact mode. Alignment errors that may occur during lowering of the imprint mold to the substrate surface and the imprint into the resist can be corrected within certain margins. The extremely small gap as well as the strong parallelism between mold and resist surface enhances signal quality and the achievable resolution. In this contribution, this paper presents some details of an alignment technique constructed by grating mark on mold and wafer. This method is like grating interferometry, but the tiny distance between mold and wafer let the theory and result totally different. Even based on different theory, both methods can provide high accuracies under 100nm.誌謝...................................................................................................................... i 中文摘要............................................................................................................ iii 英文摘要............................................................................................................ iv 目錄.................................................................................................................... vi 圖目錄..............................................................................................................viii 表目錄................................................................................................................ xi 第1 章 緒論....................................................................................................... 1 1.1 研究動機.............................................................................................. 1 1.2 文獻回顧.............................................................................................. 3 1.2.1 奈米壓印微影............................................................................ 3 1.2.2 微影疊對技術............................................................................ 7 1.2.3 奈米壓印疊對方式.................................................................... 9 1.3 論文架構及概要................................................................................ 13 第2 章 光學定位系統之原理......................................................................... 15 2.1 成像原理............................................................................................ 15 2.1.1 光的數學表示式...................................................................... 15 2.1.2 基本成像理論.......................................................................... 17 2.2 繞射式光學尺原理............................................................................ 21 2.2.1 繞射式光柵原理...................................................................... 22 2.2.2 光柵移動造成相位偏移.......................................................... 24 2.2.3 光波干涉原理.......................................................................... 26 2.2.4 相差原理.................................................................................. 28 第3 章 系統架構設計與組裝......................................................................... 36 3.1 奈米壓印機台架構............................................................................ 36 3.2 光學定位系統設計............................................................................ 37 3.2.1 近場光學量測.......................................................................... 37 3.2.2 遠場光學量測.......................................................................... 42 3.3 三軸微動精密平台設計與選擇........................................................ 48 3.3.1 三軸微動精密平台規格訂定.................................................. 49 3.4 壓印定位系統重要參數.................................................................... 54 3.4.1 數值孔徑(N.A.值)的選擇....................................................... 54 3.4.2 影像接收系統評估.................................................................. 55 第4 章 系統模擬與分析................................................................................. 58 4.1 G-Solver™理論介紹........................................................................... 59 4.1.1 RCWA 理論介紹...................................................................... 59 4.1.2 建立模擬基礎.......................................................................... 65 4.2 OptiFDTD 理論介紹........................................................................... 68 4.2.1 Yee 的FDTD 演算法............................................................... 69 4.2.2 穩定準則.................................................................................. 72 4.2.3 吸收邊界(Absorbing Boundary Condition)的處理................ 74 4.3 光柵偏移訊號分析............................................................................ 80 4.4 最佳化光柵幾何外型........................................................................ 85 4.5 母模與晶圓面間距離與繞射效率的關係........................................ 89 4.6 結論.................................................................................................... 93 第5 章 壓印定位系統之校驗與結果............................................................. 95 5.1 實驗方法............................................................................................ 95 5.2 光路校正方式.................................................................................... 96 5.3 運動平台控制系統............................................................................ 97 5.3.1 PID 控制基本架構................................................................... 97 5.3.2 XYθ 運動控制........................................................................ 100 5.4 實驗結果與分析.............................................................................. 104 第6 章 結論與未來展望............................................................................... 113 6.1 結論.................................................................................................. 113 6.2 未來展望.......................................................................................... 113 參考文獻......................................................................................................... 1163369866 bytesapplication/pdfen-US奈米壓印疊對技術位移平台繞射式光學尺nano-imprintlithographyoverlap controlprecision alignmentdiffractive laser encoderthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/51053/1/ntu-94-R92525014-1.pdf