溶劑回火誘導嵌段共聚物於高低差奈米圖案基上之取向自組裝

Directed Self-Assembly of Block Copolymer on Topographic Nanopatterns by Solvent Annealing

齊冠雄(Chi, Kuan Hsiung)

指導教授 ： 何榮銘

國立清華大學/工學院/化學工程學系/碩士(2015年)

摘要

利用可降解的嵌段共聚物製備奈米微結構薄膜，由於具有結構的特性，在各領域的應用研究上獲得高度關注。如何達到嵌段共聚物薄膜微結構之有序性與定向性為實際應用的關鍵。本研究擬利用微影製程製備具有高低差的奈米圖案基材，再透過取向自組裝（Directed self-assembly）的方式，以溶劑回火（Solvent annealing）的方法，將可降解之雙嵌段共聚物－聚苯乙烯共聚聚左旋乳酸　(polystyrene-b-poly(L-lactide), PS-PLLA)，進行奈米網狀微結構薄膜之製備。研究發現可利用共聚物有序化之成核成長機制，利用奈米圖案側壁以及角落為成核點，引導PS-PLLA於界面進行排整，促使奈米網狀微結構大規模有序排整。接著，利用PLLA可分解的特性，以溼式的水解或是乾式的反應性離子蝕刻(Reactive ions etching)方式，將其PLLA移除，進一步得到大規模排整之高有序多孔PS薄膜。此奈米多孔薄膜可利用為模板，進行溶凝膠反應，於移除模板後可製備高有序奈米多孔的無機材料。研究結果顯示，可結合由大至小的微影蝕刻製程與由小至大的嵌段共聚物自組裝行為，成功獲得奈米網狀微結構。

關鍵字

嵌段共聚物 ； 取向自組裝 ； 高低差奈米圖案基材 ； 溶劑回火

並列摘要

The fabrication of nanostructured thin films from the self-assembly of degradable block copolymers (BCPs) has attracted extensive attention in the past decade, and a variety of appealing applications in different research areas have been suggested by using the nanostructured thin films. To create useful BCP thin films for practical uses, controlled ordering of self-assembled nanostructures is essential. In this study, we aim to fabricate network-like thin films through directed self-assembly (DSA) using topographic patterns fabricated by a unique lithographic approach for solvent annealing a degradable block BCP, polystyrene-block-poly(L-lactide) (PS-PLLA). With the topographic effect on self-assembly, interesting network-like morphology can be obtained. Self-ordering of the PS-PLLA can be nucleated from the sides and corners in the trench of the pre-patterned substrate from nanolithography with specific functionalized surface, followed by the growth to give well-defined nanostructured BCP thin films, in particular nanonetwork texture. By taking advantage of degradable character of the PLLA, nanoporous PS with well-defined texture can be fabricated by a wet process through hydrolysis and also a dry process through reactive ions etching (RIE) due to the etching contrast between PS and PLLA, giving a well-defined nanoporous thin films. Using the fabricated nanoporous thin films with well-defined textures as templates, it is feasible to fabricate nanoporous inorganic networks through templated sol-gel reaction after removal of the PS template. With the integration of top-down and bottom-up approaches, we demonstrate the feasibility to create network-like texture in nanoscale dimension within the nanolithographic pattern that gives rise to promising applications in different areas.

並列關鍵字

Block copolymer ； Directed self-assembly ； Topographic nanopattern ； Solvent annealing

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