特徵尺寸與製程條件對奈米級金屬直接壓印成形性之影響

Effects of Pattern Size and Process Parameters on the Formability of Metallic Direct Nanoimprint Technology

熊欣怡(Hsin-Yi Hsiung)

指導教授 ： 宋震國

國立清華大學/工學院/動力機械工程學系/博士(2007年)

摘要

本論文之目標在於研究奈米級金屬直接壓印之成形技術，期望使金屬材料在較高分子材料難成形之情況下，仍有較佳的轉印效果。壓印技術中影響成形性的因素很多，本研究主要考慮薄膜特性、模具尺寸以及製程參數等對奈米結構成形性之影響。首先，藉由分子動力學模擬以了解金屬直接壓印之成形機制，並與金屬塑性加工理論相互比較；同時探討上述幾何尺寸與製程條件之變化對成形性的影響。
實驗中利用電子束直寫奈米級結構於矽晶圓上而製成模具；同時採用直流與離子束溅镀法製作金屬薄膜；再以直接壓印的方式轉印圖形於金屬薄膜上。在模具之尺寸效應方面，本文以兩個無因次化的參數來進行分析：模穴寬度與節距比及深寬比；製程參數則包含溫度及保壓時間對壓印成型結果之影響；薄膜特性則包含不同材料之金屬薄膜及薄膜厚度，並觀察薄膜特性與模具尺寸及製程參數間之交互影響。
成形結果之評估方面，本文是以壓印完成之圖形高度、上寬度、下寬度分別與模具對應位置之尺寸比例，稱之為填充率，作為壓印結果之品質指標，分別比較不同模穴寬度與節距比及深寬比對金屬直接壓印之影響。其後，再分別以不同的壓印溫度及保壓時間等製程參數，觀察對不同模具尺寸之壓印結果，以期獲得最佳之成形品質。最後，將模具轉印奈米結構於金及鋁薄膜之上，觀察模具壓印後之損壞情形以及壓印完成圖形的表面形貌。

關鍵字

金屬直接奈米壓印 ； 模具損耗 ； 模具尺寸 ； 製程參數 ； 圖案成型 ； 分子動力學模擬

並列摘要

This dissertation presents mainly an experimental investigation into the effects of the metallic thin films properties, mold geometries, and process parameters on the formation of nano patterns on metallic thin films by using direct nanoimprint technique. By the application of molecular dynamics simulation, a theoretical study was performed first for the purpose of understanding the formation mechanism of the proposed direct nanoimprint. In the experiment, the silicon mold with nano-scale patterns was fabricated by the direct writing of electron beam lithography and the metallic thin films were prepared by using DC sputtering as well as ion-beam sputtering. For the purpose of studying the effects of the feature size on the formation of nanostructure the mold geometry, herein, was characterized by two non-dimensional parameters: mold-cavity- width-to-pitch (WP) ratio and aspect ratio. The process parameters considered in this study, which could influence the formability and sustainability of the formed pattern, consisted of temperature and pressure holding time. In addition, the characteristics of the thin films discussed herein covered the types of metallic materials and their thicknesses.
After the imprint experiment, the pattern transferred results under various geometry and process parameters were observed. Meanwhile, the reciprocal effects existing among the WP ratio, aspect ratio, and the thickness of metallic thin film were also examined. The quality of the formed pattern was evaluated by employing the index of pattern- formation ratio that was defined by the height and width of the formed pattern divided by the corresponding geometries of the mold. Besides, the surface profile of the transferred pattern was also an important index of quality observed herein. Finally, the mold abrasion that could reduce the life of the mold due to wear was examined carefully.

並列關鍵字

Direct metallic nanoimprint ； Mold abrasion ； Geometrical parameters ； Process parameters ； Pattern formation ； Molecular dynamics simulation

參考文獻

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