斜向金屬鍍膜於製作可變線寬奈米壓印模具之研究

Fabrication of Tunable Linewidth Nanoimprint Stamps using Oblique Metal Deposition

林智賢(Chih-Hsien Lin)

指導教授 ： 宋震國

國立清華大學/工學院/動力機械工程學系/碩士(2012年)

摘要

對於奈米壓印技術而言，模具往往是製程的關鍵，但因為光學限制、成本以及時間等因素，加上線寬縮小的要求，現有製作方法已無法滿足精度的需求或成本過高，本文利用現有模具結構之壓印光阻，整合斜向金屬鍍膜與電漿蝕刻，提出模具製作方法，並透過金屬遮罩提供更多的模具材料選擇性。再藉由電漿側蝕效應改變結構線寬與斜向金屬鍍膜改變結構之Duty cycle，得到可變線寬尺寸；透過感應耦合電漿蝕刻將圖案完整地轉移至基板，完成模具的製作。使用SEM分析實驗前後圖案轉移程度與幾何形貌的觀測，依據各實驗參數與實驗結果的關係，得到實驗趨勢或函數關係。
本文利用側蝕效應將週期為144 nm之光阻線寬由57 nm縮減至30 nm，經由兩次斜向金屬鍍膜製作金屬/高分子對稱性結構，取代介電層作為蝕刻遮罩，利用金屬較佳之抗蝕刻性可製作出深寬比皆達3以上的矽結構。對於已完成結構進行電漿修整，在保有足夠深寬比以及不破壞整體結構下增加拔模角，降低因拔模角欠佳的缺陷產生。透過上述實驗結果驗證本製程可製作出可變線寬之奈米結構，並具備快速、低成本與大面積結構之優點。

關鍵字

奈米壓印 ； 斜向金屬鍍膜 ； 電漿蝕刻 ； 壓印工作模具

並列摘要

Conventionally, the master stamp for nanoimprint lithography (NIL) is made of silicon by e-beam lithography when pursuing very high precision, which needs a great amount of time and cost for manufacturing. In addition, diverse applications require variable linewidth and pitches for obtaining demanded performance. This study proposes an efficient method for making working stamps with tunable linewidth or pitch using the identical master stamp.
The pattern of the master stamp was, first, replicated to the imprint resist, underneath which silicon oxide as the release layer was deposited on silicon wafers. Then, resist trimming process was applied to reduce the linewidth of imprinted resist structures from 57 nm to 37 nm by controlling the etching time and double oblique deposition was utilized (by controlling the deposition angle and thickness) for making symmetric aluminum onto the specific region of the resist grating, herein, the top and sidewall regions. The thicknesses of deposited aluminum ranged from 10 nm to 20 nm, which resulted in different linewidth of the grating. Finally, the required duty cycle of the working stamp was formed on the substrate by reactive ion etching using the resist and aluminum as the etching mask, which was followed by immersing the etched substrate in buffered oxide etch solution to remove silicon oxide and the material above. Compared with previous researches, this proposed technique could provide the wide linewidth adjustment range at least 65% of the original one.
In summary, the study can fabricate the working stamp either the identical pattern of the master one, or tunable linewidth or pitches, even though the original one is contaminated after a number of imprints. Instead of using CVD for depositing metallic etching mask that is usually accompanied with high process temperature, this paper employed PVD for providing more adaptability of handling polymeric substrates for the applications of flexible electronics.

並列關鍵字

nanoimprint ； oblique deposition ； reactive ion etching ； working stamp

參考文獻

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