電漿子透鏡之設計與製作及應用於微影技術

The Design and Fabrication of Plasmonic Lens and Its Application of Lithography Technique

姜國安(Guo-An Jiang)

指導教授 ： 李有璋

中原大學/工學院/機械工程研究所/碩士(2018年)

https://doi.org/10.6840/cycu201800658

摘要

光學元件的微小化，是目前各式電子產品的趨勢。而在元件微小化的同時，又不改變元件特性已成為各研究單位努力的目標。有別於傳統的聚焦光學元件，電漿子透鏡主要是由金屬表面的微結構以達到聚焦的效果，不需要有複雜的三維結構設計，更因為此特性使電漿子透鏡可以以平面的形式存在，因此達到光學元件微小化的目的。本論文研究表面具有同心圓狹縫結構的電漿子透鏡，首先利用有限時域差分法(Finite difference time domain, FDTD)探討電漿子透鏡的各個參數：介電材料、金屬鍍膜厚度、狹縫寬度、狹縫半徑，對聚焦特性的影響。根據模擬結果，找出最佳化的幾何參數：介電材料為銀、金屬薄膜厚度150 nm、狹縫寬度為200 nm，狹縫半徑為1.35 μm、1.9 μm、2.5 μm的同心圓結構;在製程方面，先以熱蒸鍍方式在ITO導電玻璃蒸鍍厚度150 nm的銀，再以聚焦離子束以高能離子束進行製作同心圓的材料剝離，製作出的電漿子透鏡。此透鏡被運用在雷射直寫曝光實驗，以波長為405 nm，功率30 mW的雷射為入射光，控制移動平台之線速度為0.975 mm/s，成功的定義出線寬為次微米260 nm的直線結構。

關鍵字

電漿子透鏡；微影技術

並列摘要

The miniaturization of optical element is the trend of various electronic products. However, the characteristics of the optical element should not be changed when its size is minimized. Plasmonic lens is a plane form lens composed of the microstructure of the metal surface to achieve the focusing effect. Different from the conventional focusing lens, the plasmonic lens is without the need for complicated three-dimensional structural design. In this thesis, the plasmonic lens with concentric circular slit structure on the surface was to study and fabricate the plasmonic lens. The Finite Difference Time Domain (FDTD) method was used to analyze the influence of parameters (such as types of dielectric metal, metal coating thickness, slit width and slit radius) on the focusing characteristics. According to the simulation results, the best geometric parameters are: the dielectric metal is silver, the thickness of the metal film is 150 nm, the slit width is 200 nm, and the slit radius is 1.35 μm, 1.9 μm, 2.5 μm, respectively for concentric circle structure. The fabrication of plasmonic lens was produced by the thermal evaporation of 150 nm thick silver, and high energy focused ion beam (FIB) was used to ablate the silver to form the concentric circles. The plasmonic lens was used to the laser direct writing experiment. The laser with a wavelength of 405 nm and a power of 30 mW passes the plasmonic lens to focus the laser light on the photoresist of the silicon. The exposure experiment was processed at the linear table with velocity of 0.975 mm/s. A straight line with a minimized line width of 260 nm was defined successfully.

並列關鍵字

Plasmonic Lens；Lithography Technique

參考文獻

[1]R.W. Wood, 1902, “On a remarkable case of uneven distribution of light in a diffraction grating spectrum”,Philosophical Magazine, Vol. 4, Iss. 21, pp. 396-402.

[2]U. Fano, 1941, “The Theory of Anomalous Diffraction Gratings and of Quasi-Stationary Waves on Metallic Surfaces”, Optical Society, Vol. 31, Iss. 3, pp. 213-222.

[3]R. H. Ritchie, 1957, “Plasma Losses by Fast Electrons in Thin Films”, American Physical Society, Vol. 106, Iss. 5, pp. 874

[4]Martin Moskovits, 1985, “Surface-enhanced spectroscopy”,APS physics, Vol. 57, pp. 783

[5]H. A. Atwater, 2007, “The Promise of Plasmonics”, Scientific American, Vol. 296, pp. 56-62.