本論文研究重點為開發新型溶劑輔助式圖案轉移技術(solvent-assisted imprinting lithography)，研究弱溶劑於軟性矽膠模具(PDMS)與高分子阻劑的膨潤及軟化特性，探討其成形機制，以低溫、低壓、快速且大面積化之特點，在高分子、金屬表面製作微奈米圖案，並結合電鍍、濕式蝕刻、陽極化等過程，製備各種具功能性之微結構，預期對於現今奈米壓印技術的突破具有極大助益。
本研究利用軟性矽膠模具(PDMS)可微量吸收/釋放溶劑的特性，將膨潤狀態模具以0.001-0.01MPa 壓印於高分子塗層。溶劑分子由模具界面釋放軟化高分子塗層並使其具流動性填充模具成形，膨潤狀態(swelling)的高分子具有極佳成形性質，可成形微米至奈米等級的規則圖案，在此對於光柵圖案(pitch 277nm~1600nm)具有良好的複製成形特性，並可在低溫低壓環境進行大面積圖案轉移(5x5cm2)。接著引入氣體滲透薄膜蒸發(pervaporation)的概念，以厚度0.5-1mm之膜片式軟性模板為溶劑分子傳輸介質，藉此控制溶劑分子擴散並軟化極薄高分子層(<100nm)，軟性膜片可藉凡得瓦力完整貼合試片表面，高分子塗層在溶劑蒸氣環境下，可控制模具膨潤比為1.05，避免模具變形，且藉調整塗層厚度製作無殘餘層高分子圖案，以利後續蝕刻製作矽模具及選擇性電鍍鎳金屬於導電基板。由於PDMS膜片具良好的可撓性，以溶劑輔助方式可成功於曲面基板轉印奈米圖案，相較於熱壓印製程原理上的限制，局部膨潤軟化機制可用於二次壓印圖案疊加。
本研究亦利用PS薄膜在丙酮溶劑下的除潤現象，於壓印高分子微米圖案的表面，藉由丙酮處理使連續圖案選區除潤縮合成規則PS球狀排列，並控制壓印圖案之殘餘層厚度，製作規則且具層級結構的高分子球狀陣列，更進一步製作圖案間距277nm及555nm的點狀圖案，經丙酮處理後可分別得到規則的奈米PS光子晶體排列。
最後利用擴散反應機制(reaction-diffusion) 結合溶劑輔助壓印製程，提出一新穎鋁表面圖案化方法，以混合有機溶劑與微量蝕刻液，由軟性模板擴散並在模版及金屬界面反應，於金屬表面選擇性蝕刻形成規則圖案，再經陽極化製程導引圖案成長規則氧化鋁奈米孔洞。以此模具輔助化學蝕刻法，分別以不同尺寸之光柵圖案模具(277、420及555 nm)調整二次圖案疊加角度(30°、60° 及90°)，可於鋁表面製作規則凹坑導引氧化鋁孔洞成長，並調整陽極化電壓控制孔洞間距，以探討預圖案對於孔洞成長行為之影響。

The rapid and effective pattern transfer method would be empolyed by the solvent-assisted imprinting lithography. Polymethylmethacrylate (PMMA) and ethyl alcohol (EtOH) are chosen for demonstrating a solvent-assisted imprint process working at room temperature and low pressure (0.001~0.01 MPa) with a soft mold. The poor solvents (such as EtOH, acetone and THF) cause a physical swelling reaction for both the PDMS mold and polymer resist (such as PMMA, PS and PC). The swollen PMMA gel has excellent filling capability for applying in imprinting lithography. During imprinting process, the PDMS mold absorbs the poor solvent from the resist, which deswells the polymer gel and helps pattern setting. This method can be applied extensively for micro-nanolithography and plastics industry to prepare micron-nanometer scale structures. Besides, by controlling the imprinting conditions, the residual-layer-free pattern through the polymer dewetting effect could be obtained.
The solvent vapor-assisted imprinting lithography (SVAIL) using the flexible PDMS membrane mold (0.5-1 mm thickness) as a solvent transport medium in a vapor environment has also been demonstrated. By adjusting the solvent vapor pressure and temperature, the transport mechanism provides the sufficient solvent to soften the thin polystyrene resist (<100 nm) and avoids the unexpected deformation of imprinted nanopatterns. The idea shows the potential of SVAIL for large-area pattern (5x5 cm2) without any external loading. The residual-layer-free pattern can be obtained through the SAVIL because of the ultra thin coated polymer films. The multiple imprinting has been performed to obtain 2D hierarchical structures using simple 1D stripe patterned stamps. To combine this method with wet etching process and metal electrodeposition, the Si grating and Ni pattern can be fabricated.
A controlled dewetting process for fabricating an ordered nanostructure on a polymer thin film is demonstrated. Uniform PS pattern can be fabricated at room temperature and low pressure (0.01MPa) by a solvent-assisted method. The imprinted PS microlens have marked change in morphology from dome to sphere because spinodal dewetting effects after acetone treatment. By adjusting thickness of the residual layer between imprinted domes, the self-organization PS sphere arrays with multiple sizes can be fabricated. Furthermore, the sub-micrometer PS pre-pattern can be turned into photonic crystal arrays with 555 nm pitch by dewetting process.
A simple and cost-effective method for creating patterned nanoindentations on Al surface via a mold-assisted chemical etching process has been carried out. This study shows a reaction-diffusion method which formed nanoscale shallow etch pits (25 nm deep) by the absorption/liberation behavior of etchant in PDMS stamp. After anodization, we can get the ordered nanopore arrays with 277 nm pitch that are guided by the prepatterned etch pits. The proposed method can also find applications in other metals and semiconductors for preparing ordered nanopore or nanochannel arrays through pretexturing.

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