- 學位論文
以改良式遞迴傅立葉演算法設計遠場無光罩微影技術圖形之研究與應用
Study and Application of Maskless Lithographic Patterns in Optical Far Field Using Modified Iterative Fourier Transform Algorithm
摘要
本篇論文提出利用全像投影系統（Holographic projection system, HPS）在光學遠場產生二階相位移圖形（Phase-shift patterns, PSPs）並可實際應用在非週期性結構的元件製造方法上。將設定好的遠場相位移圖形當作是目標圖形，以此目標圖形結合改良式遞迴傅立業演算法，返回計算純相位式繞射元件的最佳化場函數。將計算出來的純相位式繞射元件場函數輸入至全像投影系統中的空間光調變器（Spatial light modulator, SLM），可於系統設定的遠場投影面上得到近似的相位移圖形；遠場相位移圖形與空間光調變器上彼此間的光場形式為傅立業轉換的平方正比關係。從實驗的結果來看，我們所提出的設計方法確實建立了一種新穎且實際可行的作法，這樣的設計方法與相位移微影技術（Phase-shift lithography, PSL）的結合對於達成更小的臨界尺寸（Critical dimension）具有無限潛力，並且可實現快速且低成本的無光罩微影技術（Maskless lithography, ML）。
並列摘要
We propose a method to generate two-dimensional phase-shift patterns (PSPs) in the optical far field using a holographic projection system (HPS), which can be used to fabricate non-periodic features. The field function of PSP is used as the target function to calculate the phase-only diffractive optical element by applying an optimization of modified iterative Fourier transform algorithm (IFTA). Using the phase-only diffractive optical element as the input to the spatial light modulator (SLM) of holographic projection system, an image resembling the PSP target is obtained in the projection plane. In contrast to the PSPs, which are the images of the input to the SLM, the PSPs of the proposed method are proportional to the squared modulus of the Fourier transform of the light field from the input SLM. The results of the proposed approach can lead to the development of a novel approach that combines the promising properties of the small critical dimension achieved by the phase-shift lithography (PSL) and the high velocity and low cost of the maskless lithography (ML).