臺灣博碩士論文加值系統

摘 要
由於光源波長極限與光繞射現象限制，奈米級的結構，以目前光學微影成像技術遭遇瓶頸而且量產昂貴，發展出奈米壓印製程技術，以開發較低成本與較可靠奈米元件量產技術。本研究融合軟微影、光固化阻劑及氣體施壓技術的特點，研究使用氣體輔助軟模壓印光固化阻劑技術製作光波導元件，使奈米壓印的應用更趨成熟。

本研究首先使用氣體輔助熱壓技術將模具微結構翻製到塑膠薄膜上，澆鑄PDMS於塑膠薄膜之結構面上，得到與原始模具一樣之結構圖案，接著將光阻劑塗佈在此PDMS模具上(反轉式壓印)，再搭配氣體加壓的方式，使模具與基材達到接觸並受均勻壓力，同時照射紫外光以固化光阻劑，得到光波導雛型結構。

結果發現，PDMS可精確的翻鑄複製出微奈米級結構，搭配氣體均勻施壓，與基材表面達到完整接觸，可大幅提昇有效壓印面積；而且PDMS軟模製作容易、翻鑄時間短，可有效降低成本；加上PDMS軟模具有表面自由能低，壓印時不易與阻劑沾黏。軟模搭配氣體壓印確實是製程上一大優勢。加上使用光固化阻劑來製作元件，其無需加熱、尺寸穩定且成型速度快的特點，用來製作80μm×80μm之脊樑式光波導元件可使得殘留層減至最低，甚至無需後續的蝕刻去除殘留層的步驟，證實本製程是製作、量產奈米級元件非常好的製程技術選擇，且本論文對於製程上所產生的缺陷問題也提出了解決之道。

最後經由導光光場量測與光損失量測得到，脊樑式光波導元件在1310nm波段其傳播損耗為1.6 dB/cm。

Abstract

This thesis is devoted to the fabrication of optical waveguide using gas-assisted imprinting with soft mold. The process integrates lithography、UV curable photoresist and gas assisted pressuring mechanism into imprinting.

The microstructures on the Si molds are first replicated onto thermoplastic PC film using gas-assisted hot embossing process. PDMS molds can be obtained by casting on the PC films. UV-curable resins are spreaded on the PDMS mold employing reversal imprinting technique. The PDMS mold and SiO2 substrate are then brought in contact and pressed using gas pressure in a closed chamber.

In this process, the PDMS soft mold is used and gas is used as pressuring media. Conformal contact and uniform imprinting pressure throughout the whole area can be achieved. Furthermore, PDMS mold has low surface energy and anti-adhere to resist. It is found that fabricating optical waveguide devices using this process can reduce residual layer to minimum. The ridge-shaped waveguides of 80μm width and 80μm depth were successfully made; the propagation losses measured at 1310 nm was 1.6 dB/cm. It is demonstrated that this technique has great potential for effectively replicating large area micro-nano structures.

目 錄

致謝 Ⅰ
中文摘要 Ⅱ
英文摘要 Ⅲ
目錄 Ⅳ
表目錄 Ⅷ
圖目錄 Ⅸ


第一章 導 論
1.1 前言 1
1.2 半導體光微影技術限制 1
1.3 奈米壓印製程與其關鍵技術 3
1.4 氣體微壓印成型方法 4
1.5 光波導簡介 5
1.6 研究動機與目的 6
1.7 論文內容架構 7

第二章 文獻回顧
2.1 各種奈米轉印技術簡介 13
2.1.1 熱壓式奈米壓印微影(NIL) 13
2.1.2 紫外光奈米壓印微影術(UV-NIL) 14
2.1.3 步進快閃式壓印微影(SFIL) 15
2.1.4 反轉式壓印(Reversal Imprinting) 15
2.1.5 軟蝕刻微影成像技術 16
2.1.6 雷射輔助式奈米壓印(LADI) 16
2.2 紫外光輔助奈米壓印微影文獻回顧 17
2.3 綜合歸納 17

第三章 實驗設置與實驗方法
3.1 光波導元件壓印設備與方法 23
3.1.1 壓印設備 23
3.1.2 壓印製程步驟 24
3.1.3 紫外光固化設備 25
3.2 壓印模具製備與翻模技術 26
3.2.1 塑膠熱壓成型翻模 26
3.2.2 PDMS翻模 27
3.2.3 翻模成品量測評估儀器 30
3.3 緩衝層(氧化層)製作 31
3.3.1 PECVD薄膜沉積 31
3.3.2 緩衝層製作與參數設計 31
3.3.3 緩衝層厚度選擇 32
3.4 阻劑性質、製備與塗佈 32
3.4.1 光波導核心層(Core Layer)材料 32
3.4.2 光波導披覆層(Cladding Layer)材料 33
3.4.3 壓印用光阻材料 34
3.5 光波導量測系統架設與說明 34
3.6 本章結論 35

第四章 光波導元件製作
4.1 材料的選擇 49
4.2 脊樑式波導元件製作 50
4.2.1 脊樑式波導元件製作流程 50
4.2.2 壓印成型複製性探討 52
4.2.3 壓印成型缺陷探討 54
4.3 埋藏式波導元件製作 56
4.3.1 埋藏式波導元件製作流程 56
4.3.2 壓印成型複製性探討 59
4.3.3 壓印成型缺陷探討 60
4.4 乾蝕刻後的分析 60
4.5 本章結論 61

第五章 光波導量測結果與檢測分析
5.1 光波導量測結果 76
5.2 造成元件能量損耗的因素 77
5.3 奈米壓痕(Nanoindentation)檢測波導元件之理論與方式 78
5.3.1 奈米壓痕檢測理論 78
5.3.2 奈米壓痕檢測原理與應用 79
5.4 奈米壓痕檢測波導元件之結果與分析 80
5.4.1 負荷大小對波導元件之壓痕行為影響 80
5.4.2 以奈米壓痕檢測波導元件機械性質 80
5.5 本章結論 81

第六章 結論與未來研究方向
6.1 結論 87
6.2 未來研究方向 88

參考文獻 89
附錄A 奈米壓痕檢測儀 92
附錄B 已發表著作 93

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