摘要
以直接金屬奈米壓印法(Direct metal nanoimprint)可以在矽基板的金屬薄膜上直接壓印出金屬光柵圖案，接著可將金屬光柵圖案嵌入透明高分子基材中，製作LCD背光模組中具偏振功能的複合線光柵偏振片(Composite Wire Grid Polarizer)，上述創新製成程可以取代半導體產業普遍使用的黃光微影製程，將微影製程繁複的步驟簡化，可大幅提升產量，降低製作成本，影響此製程最關鍵的步驟是在直接金屬奈米壓印步驟中金屬材料能夠複製模仁所設計的奈米級柵狀圖案，達到製作偏振片目的。 以電子束微影 (E-beam lithography) 製作柵狀線寬300 nm矽模仁，以金/矽疊層作為基板，在環境溫度120℃下，以負荷3800 kg進行直接金屬奈米壓印，發現由光柵組成的正方型圖案(0.5 × 0.5 mm2)中，邊緣光柵成型性較中央佳，金光柵成型高度不平均的現象。 有限元素模擬部分以實驗邊界條件作為基礎，以Simufact模擬軟體分析金薄膜在多齒模仁中的流動情形以及受力狀態，在模仁為剛體條件下，能觀察到光柵圖案中，中央模齒下方金薄膜流動互相影響、牽制，金薄膜流動受拘束，造成邊緣光柵流動性較中央佳，壓印方向應力較中央低、等效應力較中央高，上述現象會隨模齒尺寸的縮小而更加明顯。在模仁為彈性體的條件下觀察模仁在壓印過程中的變形狀態，發現受模仁幾何形狀的影響，邊緣模齒受壓印方向應力較中央模齒小，且壓深較中央深，推斷實驗所觀察到之光柵成型高度不均為模仁彈性變形及金薄膜受力不均所導致。
並列摘要
The nanoimprint lithography for fabricating metallic nano-features on silicon or polymer substrate requires a series of complicated processes including repeated deposition, etching and lift-off. We developed an novel integrated direct nanoimprint process for fabricating bi-layered metallic wire-grid polarizers (WGP), including 1. direct nanoimprint on metal film, 2. novel stack flip transfer technique for the inserting of metal pattern onto polymers substrate and 3. the reactive ion etching (RIE) for the removing of residual metal layer and for the selective etching on polymer. This technique offers a low-cost, time-saving, and straightforward patterning process to produce stack-layered metal/polymer composite wire gratings. Non-uniform filling after direct nanoimprint of gold gratings was found by SEM-FIB section observation. While the rim of the grating exhibited very good fidelity and the pattern reached the full height, the area in the pattern center revealed less satisfactory filling of the metal in the spacing of the mold. This phenomenon will be explained from the viewpoint of the material flow of the Au thin film and mold deformation. A 2-D finite element analysis on the material flow during embossing revealed a higher effective stress distribution near the edge of the pattern than that in the central area, we also found that the lower vertical (embossing direction) stress distribution near the edge was lower than that in the central area. Since the material near the edge of the mold stamp is less constrained during embossing, plastic flow of the gold layer take place easier near the edge. In addition, elastic deformation of Si mold is also discussed in this research. We found that the elastic deformation of mold teeth near the edge area was less than that in the mold center area which also caused more embossing depth near the edge of the pattern than that in the central area. This may be attributed to the elastic “press back” of the teeth in the central area during embossing, The FEM results were in good agreement with the experimental observation.