간섭 리소그래피를 이용한 나노 구조의 제작

Abstract

This thesis presents a fabrication of nano structure using interference lithography. Lloyd’s mirror interferometer was employed in this system. In order to fabricate nano structures over a large area with high visibility and linewidth uniformity, the study of coherence of light and Gaussian beam was performed. This system successfully fabricated uniform nano-periodic patterns (line, dot, and hole) in a photoresist (PR) over a 2 x 2 cm area. The PR patterns agreed well with simulations. Moreover, the effect of soft baking time was investigated in interference lithography. After that, tall silicon nano structures were fabricated by deep reactive ion etching (DRIE) using a PR pattern as a direct etch mask layer. Aspect ratios >10 with smooth and vertical sidewalls were achieved after DRIE with modified recipe. Because an AlInGaN semiconductor laser has a long coherence length of 20 m (e.g., 30 cm of HeCd laser) with a low price (e.g., only 1/3 that of the HeCd laser), the cost-effective interference lithography was realized to fabricate uniform nano periodic patterns.