- 學位論文
次波長圓環元件的設計與製造及其在雷射加工上的應用
Design and fabrication of subwavelength annular aperture and its application to laser machining
摘要
光學微影技術的開發與科技產業的發展有著密不可分的關係，然而，受限於繞射極限的影響，要朝更小線寬的目標邁進，必須藉由縮短入射光波長，或者是其他輔助方式來達成，如浸潤式微影等，但上述的方法往往增加了機台設計與製造成本，進而影響到微影技術發展的腳步。 近年來奈米結構的設計與研究，已廣泛地被討論與應用，本論文利用表面電漿光學的原理，設計與製造次波長奈米金屬結構，本論文中提出了銀的次波長圓環結構與氧化鋁-鋁-氧化鋁的次波長圓環結構，發現此次波長圓環具有長焦深與次波長光點的光學特性，結合飛秒雷射與準分子雷射，建立一台貝索光束雷射加工直寫儀，可應用於矽晶圓微加工上。 模擬方面利用自行組建的電腦叢集，利用平行運算的技術，搭配有限時域差分法，進行次波長圓環結構的光學特性模擬，並嘗試將不同的入射光源與偏極態入射到次波長圓環結構，比較次波長圓環結構穿透能量的變化，這些模擬結果將有助於我們在次波長圓環結構的參數設計。 實驗方面，為了驗證圓環直徑與焦深的關聯性，我們利用電子束微影搭配金屬剝離法來製作大直徑圓環。由實驗結果得知焦深會隨著圓環直徑增加而變長的趨勢，這意味著我們可以藉由改變圓環直徑的大小而去控制焦深的長短。應用方面，本論文將次波長圓環結構整合在現有的貝索光束直寫儀，並搭配飛秒雷射與準分子雷射時，該系統可以在矽晶圓上進行微加工，以證明我們設計的次波長圓環結構，具有雷射加工與鑽孔的能力。
並列摘要
Traditional optical systems are affected by diffraction limit such that its focal spot size is limited by the incident wavelength and numerical aperture of the system. In order to shrink the focal spot, two common methods are typically used. One method is to reduce the wavelength of the light source, and another is to increase the numerical aperture of the lens. However, the high cost of light source and the rarity of lens material at shorter wavelength obstruct the development of lithography techniques. In recent years, the fabrication and design of subwavelength annular aperture (SAA) structure have been developed well. In this thesis, we used the principle of surface plasmon to design and fabricate the SAA structure. We proposed silver and Al2O3-Al-Al2O3 SAA structures. Utilizing these nontraditional phenomena, the SAA structure possesses both ultra-long depth of focus (DOF) and a few hundreds of nanometer spot size simultaneously. We also established a Bessel beam writer system which is integrated with SAA structure and high energy laser system such as femtosecond or Excimer laser. For the simulations part, we demonstrated the far-field optical properties of different polarization and different light source of metallic SAA structure by using three-dimensional FDTD simulations. We also compared the optical transmission results of a metallic SAA structure with different polarization and light source. For the experimental parts, we demonstrated a new technique which uses electron beam lithography (EBL) for pattern generation followed by a metal lift-off process to fabricate a large size SAA structure on metallic film deposited on top of a glass substrate. We can see that by adopting this technique, we can significantly extend the DOF by increasing the diameter of the SAA structure. In practical applications, we demonstrated a new technique which focuses a Ti:sapphire femtosecond and Excimer laser onto an oxide-metal-oxide (Al2O3/Al/Al2O3) film on a glass substrate engraved with a SAA structure. We found that SAA structure is one of the best choices to develop a Bessel beam writer system prototype that can produce high aspect ratio laser-machining easily and conveniently within an atmospheric environment in the future.