利用奈米壓印法製作奈米陣列結構

Abstract

自從周郁提出奈米壓印的技術後，這種技術相當具有在半導體製程及奈米技術上取代光微影的潛力，隨後Williston與Whiteside等人接續提出不同類型的奈米壓印後，更加深了奈米壓印應用的領域。由於奈米壓印技術技術不論時間或材料的耗費上均可大量的降低，更重要的是能突破光學繞射的限制，使得製程的尺度也同時大幅的降低，然而在低壓力下壓印技術與奈米結構的應力性質仍有研究。 本論文的對象在於研究高寬深比（high aspect ratio）的奈米結構。首先，高寬深比的模具在製作方式有些不同，濕蝕刻(Wet etching)在此不適用，文中將介紹本實驗採用的Hard mask製程，使用SiO2當作犧牲層，增加蝕刻區域深度。隨後我們討論脫模的機制，脫模是在壓印的過程中最關鍵的步驟，由於模具的總表面積大於基版，使得模具與壓印材料的吸附力過大，在脫膜時會有材料破裂或附著於模具的情形發生的情形發生，本實驗在模具表面以塗佈自我組裝層（SAM）降低材料與模具的表面能。接著，我們討論PS與PMMA在不同壓力、壓印時間、壓印溫度下的壓印成果，從其中尋找出最佳的壓印參數。最後測試壓印成果的應力，利用原子力顯微鏡（AFM）測試組成奈米陣列中的奈米圓柱的受力，測量圓柱在AFM下壓與上提時的比較，即可得每一圓柱的引力，將微觀與巨觀的表現結果比較後探討其中的原因。

Before long, it could come true that nanoimprint lithography will replace photolithography in semiconductor manufacture and nano technology. After Stephen Y. Chou, related technologies proposed by C. G. Wilson and G. M. Whiteside make it more possible. One reason is that nanoimprint can save much more cost and time waste in manufacture. More important one is the breakthrough about the diffraction of light. Although nanoimprint is highly developed, the fabrication under low pressure and the mechanics must be investigated. The researched object of this article is the nanostructure with high aspect ratio. In the first, we will introduce hard mask manufacture. In the method, SiO2 is used as a sacrificial layer to make deeper etch length. The most important part of nanoimpirnt is the leaf off process. Because the mold contains more surface area than the substrate, the adhesion force is asymmetric on both sides. It usually results to fracture or incomplete leaf off. Then we will show how to minimize the adhesion force between mold and polymer by coating an SAM layer. Thereafter, we will compare the results of PS and PMMA under different pressure, imprint time and temperature and find out the best parameters. At last, we will measure the force curve by AFM. The reasons why the mechanics of micro behavior and macro one are different will be discussed in the conclusion.