氣輔軟模紫外光固化微奈米壓印製程應用於製作光波導元件之研究

Fabrication of Optical Waveguide Devices Using Gas-Assisted UV Nanoimprinting with Soft Mold

翁永春(Yung-Chun Weng)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.10077

摘要

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。

關鍵字

紫外光奈米壓印 ； 氣體加壓機制 ； PDMS軟模具 ； 光波導 ； 完整接觸 ； 反轉式壓印 ； 奈米壓痕

並列摘要

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.

並列關鍵字

Ultraviolet Nanoimprinting ； Gas-Assisted pressuring mechanism ； PDMS soft mould ； Optical Waveguide ； Conformal contact ； Reversal Imprinting ； Nanoindentation

參考文獻

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