四氟乙烷電漿沉積氟碳複合結構薄膜製程之研究

Process-structure-property Relationship of 1,1,1,2-tetrafluoroethane Plasma Deposited Fluorocarbon Films with Composite Structures

陳榮俊(Rong-Jyun Chen)

指導教授 ： 魏大欽

中原大學/工學院/化學工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200630

摘要

本研究以1,1,1,2-C2H2F4電漿製備氟碳複合結構薄膜，並以四極柱質譜儀（QMS）以及電漿放射光譜（OES）分析沉積過程中電漿中物種變化，電漿氟碳膜表面使用接觸角量測儀、FE-SEM、AFM、XPS等儀器，分析表面物理結構和表面化學元素組成之變化。探討電漿製程參數、氟碳膜之物理與化學結構以及疏水特性三者間之相互關係。
　　研究中發現透過RF功率、操作壓力及惰性氣體（Ar）的添加，皆能控制成膜自由濃度或/與反應物種滯留時間，來調整氣相與異相聚合反應程度。在高成膜自由基濃度與較長的滯留時間下，其聚合反應主要以氣相為主。因此在沉積膜上的粉體密度較大，而粉體密度的增加可有效提升表面粗糙因子（roughness factor），對於動靜態接觸角皆有明顯的幫助。透過AFM分析超疏水化（WCA：~165˚）氟碳膜面，其粗糙因子高達1.74。經Cassie model計算後，氟碳複合結構薄膜表面液固接觸面積（solid fraction）僅為0.04。使膜面對於液滴之吸引力下降，而後退角提升並減少接觸角遲滯現象，而達到優異的疏水特性（sliding angle：~7˚）。
　　電漿氟碳膜之氟碳比經XPS分析後約落在0.8-1.2之間，與單體氟碳比相近。在研究中也發現氟碳比隨沉積時間有先升後降在持平之趨勢，轉折點於45 sec.，此時氟碳比大小隨單體流率的增加而下降（F/C ratio = 1.22 @ 3 sccm）。而隨Ar添加量之提升，將造成沉積膜交聯度提高而氟碳比下降。
　　本研究亦成功將超疏水氟碳複合結構薄膜，應用於低操作電壓之介電潤濕（EWOD）裝置上。僅需10 V之操作電壓即可使接觸角改變量達13˚，而最大接觸角改變量可達66˚，且光學性質佳。

關鍵字

超疏水 ； 氣相成核 ； 電漿放射光譜儀 ； 電漿沉積 ； 介電潤濕現象 ； 四極柱質譜儀 ； 四氟乙烷

並列摘要

In this study, the composite structures of fluorocarbon films were prepared by 1,1,1,2-C2H2F4 plamsa. The plasma diagnostics (OES and QMS) and surface analysis (CA, UV/Vis, XPS, FE-SEM and AFM) were used to elucidate the process-structure-property relationship of fluorocarbon films deposited in 13.56 MHz RF plasma reactor.
　　The results revealed that rf power, operating pressure and gas flow ratio (C2H2F4/Argon) could control the concentrations of free radicals and/or retention time of reactive species. As a result, the extent of homogeneous and heterogeneous polymerization was affected. It prefers gas-phase nucleation in higher concentration of free radical and longer retention time of reactive species, resulting in not only roughed surface but also increased hydrophobicity of surface significantly. The AFM analysis indicated that roughness factor of super-hydrophobic film is about 1.74. Using the Cassie-Baxter model, surface solid fraction is about 0.04, resulting in a very low contact angle hysteresis.
　　As revealed by XPS analysis, the fluorine/carbon (F/C) ratio of deposited films was between 0.8-1.2, very close to the F/C ratio of monomer. Moreover, with increasing deposition time, the F/C ratio of deposited films increased firstly and then decreased to a constant value. The turning point was at 45 seconds, and the F/C ratio of deposited films decreases with increasing flow rate at this time.
　　Finally, we successfully applied super-hydrophobic fluorocarbon film to electrowetting-on-dielectrics device with low operating voltage. It just needed 10 volt of operating voltage to change 13 degrees of contact angle, and the maximum contact angle change (Δθ) was 66 degrees. Additionally, the device has excellent visible light transmittance.

並列關鍵字

plasma deposition ； C2H2F4 ； super-hydrophobic ； gas-phase nucleation ； plasma diagnostic ； electrowetting on dielectrics

參考文獻

[9] 劉志宏, "應用實驗設計法與電漿診斷技術探討電漿沉積氟碳膜製程之研究," 私立中原大學碩士論文, 2005.

[19] 古奕凡, "聚丙烯膜材表面超疏水化電漿改質技術及形成機制之研究," 私立中原大學碩士論文, 2009.

[33] 鐘沛宏, "聚甲基丙烯酸甲酯膜材表面超疏水化電漿改質技術之研究," 私立中原大學碩士論文, 2011.

[35] 張文豪, "以電漿輔助化學氣相沉積法製備超疏水薄膜及形成機制之研究," 私立中原大學碩士論文, 2010.

[47] 林佩穎, "以電漿放射光譜技術探討電漿表面改質高分子膜之研究," 私立中原大學碩士論文, 2006.