複合微奈米PDMS模具之製作與應用

Fabrication and Application of Micro/Nano Hybrid PDMS Mold

黃奕豪(Yi-Hao Huang)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01580

摘要

為直接製作無殘留層的微結構，微接觸轉印、奈米接觸轉印及軟模轉印等技術陸續發展。但旋塗於模具結構凹陷處的墨水，在壓印時因軟模變形，推擠凹孔中的墨水殘留到基材上，形成殘留層。為解決此問題，模具被設計成高深寬比結構，但高深寬比的軟模結構易產生挫曲和側向變形，導致轉印失敗。
本研究設計製作複合微奈米結構模具，利用模具表面奈米結構疏水性，避免殘留層產生。本研究先使用陽極氧化鋁當模板製作疏水性奈米結構於模具表面，再製作出兼具疏水性奈米結構與微米結構的PDMS複合模具。模具之凹陷處表面因具有AAO疏水性結構，墨水不易於旋塗後殘留於其中，即使深寬比低，也不易將殘留墨水一併轉印至基材上，形成殘留層。
本研究首先製作AAO模板，然後藉由氣體輔助熱壓在聚碳酸酯(PC)基材上產生奈米結構；接著第二次氣體輔助熱壓，在定義微結構的模具上，複製微結構於此奈米結構PC基材上，得到有特徵微結構，並且表面具有疏水性奈米結構的PC薄膜；再以此PC膜為母模，用PDMS鑄造翻模，固化後得到表面疏水性的微奈米複合結構的PDMS模具。最後以之為轉印模具，證實無殘留層。
本論文之主要內容包括：一、藉由改變陽極氧化鋁製程，以各種參數製得不同的AAO模板之奈米結構，並證實以AAO模板確實可製得具疏水性的PDMS表面；複製了AAO模板奈米結構的PDMS與水珠之接觸角可達150°，遠高於一般PDMS約115°的接觸角；二、以兩次氣體輔助熱壓製程，製作出兼具奈米與微米結構的PC膜，在其上澆鑄，成功製作出複合微奈米PDMS模具；三、以複合模具為轉印模具，進行以氣體及磁力施壓的軟模轉印製程，證實複合模具確實大幅改善殘留層問題。本研究並進一步使用複合模具清晰轉印光阻圖案到銅質基材上，以之為擋罩進行蝕刻，成功製作微結構，顯示以微奈米複合模具作轉印模具在光微影製程便捷的實用性。

關鍵字

轉印製程 ； 疏水性結構 ； 陽極氧化鋁 ； 複合模具

並列摘要

Micro contact printing (μCP), nano contact printing (nCP) and transfer stamping processes have been developed with the goal of direct fabrication of microstructures without residual layers. But in real cases, residual layers are frequently observed. The inks often reside in cavities of the mold structure during spin coating; these inks might be left on the substrate when the stamping or printing pressure deforms the mold.
In this research, we propose a novel method to solve the residual layer problem by using PDMS mold with micro/nano hybrid structures. The mold consists of hydrophobic nanostructures and micro structures. The hydrophobic property of nanostructures can avoid the sticking of inks in the cavities and thus prevent residual layers.
We first fabricated AAO (anodic aluminum oxide) template, and this template was then used as a mold to replicate nanostructures on PC (polycarbonate) film by gas-assisted hot embossing process. Next, we performed the second gas-assisted hot embossing process using this PC film with nanostructures as the substrate and employed a mold with micro structures to replicate micro structure to this PC substrate. After that, a PC film of protruded microstructures with AAO nanostructures was obtained. This PC film with nano/micro structures was then used as a master mold, and the PDMS (polydimethylsiloxane) resin was cast onto this master mold. After cure, a PDMS mold of hydrophobic nanostructures on surface of micro-cavity was obtained.
These are three major aspects in this research: 1. AAO templates with different geometrical characteristics of nanopores were fabricated through varying the AAO processing parameters, and the hydrophobic properties displayed in the final PDMS surface using these AAO templates were investigated. The hydrophobic property of PDMS’s surface has been significantly improced; the contact angle on the flat PDMS with nanostructures is nearly 150°, higher than that on the smooth PDMS surface, which is about 115°. 2. Micro/nano hybrid structures were fabricated on PC film using two continual gas-assisted hot embossing processes with AAO template for nanostructures and stainless mold for microstructures. PDMS was cast on this PC film as the master mold to fabricate the PDMS mold with hybrid micro/nano structures. 3. The transferred patterns using the micro/nano hybrid mold showed significantly less residual layers, compared with these transferred results using a conventional PDMS mold without hydrophobic nanostructures. The PDMS mold with hybrid micro/nano structures was used to transfer photoresist patterns, which served successfully as the mask patterns onto copper substrate during the subsequent Cu etching, showing the promising potential in applying such PDMS mold with hybrid micro/nano structures in photolithography.

並列關鍵字

transfer stamping process ； hydrophobic nanostructures ； anodic aluminum oxide ； micro/nano hybrid PDMS mold

參考文獻

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