超臨界電鍍銅製程之奈米鍍層內應力及導電性探討

The Internal Stress and Conductivity of the Nanocrystalline Copper Coating Prepared by Electroplating Process with Supercritical Carbon Dioxide

鄭鈞元(Jyun-Yuan Jheng)

指導教授 ： 李春穎

國立臺北科技大學/機電學院/機電整合研究所/碩士(2012年)

摘要

電鍍被定義為一種電沉積過程，在工業上已有廣泛之應用。其特性在改變基材表面性質，使外表更加美觀等優點為考量下，電鍍成為不可或缺之加工技術之一，而提升電鍍品質也一直為電鍍這門學問之重大目標。而超臨界為一種相態，物質在加溫加壓至超過其臨界點後，就會進入這種特性介於液體與氣體之超臨界狀態。二氧化碳在常溫常壓下為無色無味之惰性氣體，經由研究發現二氧化碳以7.39 MPa之壓力與高於31.3?C之溫度即可進入超臨界狀態，其應用大多在於超臨界萃取。由於電鍍沉積銅具有良好導電性，且在愈酸性的電鍍液中愈容易沉積，因此、常使用具有成本低廉、易於操作控制等優點之硫酸銅電解液。本研究為藉由超臨界二氧化碳之輔助，在硫酸銅鍍浴中執行電鍍銅鍍層。比較一般傳統電鍍及超臨界二氧化碳輔助下所執行之電鍍，以及有無加入添加劑所電鍍出來的鍍層在各種分析上之差異。在本研究當中成功重現並探討該製程在不同參數下之成效；而進一步嘗試改變參數再觀察其成效時，發現超臨界電鍍製程之鍍液不論有無加入添加劑，其鍍層都能夠得到一定的改善，而且還有晶粒變小、硬度提升等優點。但是卻有內應力較高的缺點，所倖在提高電流密度當中，可以有效將其降低。本論文將針對以上之研究進行分析並且嘗試探討其成因。

關鍵字

超臨界二氧化碳 ； 電鍍銅 ； 鍍層之薄膜內應力 ； 電流密度 ； 電流效率

並列摘要

Electroplating is defined as an application process of electrodeposition. It has a wide range of industrial applications which require the functional and appearance improvements over the substrate surface. Electroplating has become an integral part of the manufacturing technology and process improvement has been a major task for the engineers and scientists. The supercritical phase is a special state of a substance between liquid and gas phases in certain heated and pressurized environments which exceed its critical point. Carbon dioxide, as a colorless and odorless inert gas in the ambient temperature and pressure, becomes supercritical phase in a pressure higher than 7.39 MPa and the temperature higher than 31.3 ?C. Its applications include the well-developed supercritical fluid extraction. Electrodeposited copper has good electrical conductivity, and is more easily prepared from acidic electroplating solution, such as the low-cost, easily controlled copper sulfate electrolyte. This study focused on the implementation of the electroplated copper plating in copper sulfate bath with the assistance of supercritical carbon dioxide. Comparison between conventional plating and the supercritical carbon dioxide assisted electroplating was performed with consideration in the effects of additives in the plating bath. In this study, the effectiveness of the proposed supercritical process successfully demonstrated the potential even without additives in the plating bath. The grain size of the coating was reduced and the hardness increased accordingly. However, the internal stress of the coating increased in supercritical plating. Fortunately, by raising the current density, the internal stress can be effectively reduced. The possible underlined mechanisms for the observed experimental results were also explored in this thesis.

並列關鍵字

Supercritical Carbon Dioxide ； Copper Plating ； Coating the film internal stress ； Current Density ； Current efficiency

參考文獻

[4]陳黼澤，替代六價鉻製程研究，博士論文，國立臺灣大學機械工程學系，台北，台灣，2009年。

[3]Hideo Yoshida,Masato Sone,Aya Mizushima,Kentaro Abe,Xu Tang Tao,Shoij Ichihara,and Seizo Miyata,“Electroplating of Nanostructured Nickel in Emulsion of Supercritical Carbon Dioxide in Electrolyte Solution”，Journal of Chemistry Letters,2002, 1086-1087.

[8]劉庭宇，電流模式與界面活性劑對超臨界電鍍鎳鍍層之影響探討，碩士論

[13]Hao Yan, Masato Sone, Nonuyoshi Sato, Shoji Ichihara, Seizo Miyata,“The effects of dense carbon dioxide on nickel plating using emulsion of carbon dioxide in electroplating solution”, Surface and Coatings Technology 182, 2004, 329-334

[20]G.Gore,“On the Properties of Electro- deposited Antimony”, Trans.Roy.Soc. (London), Part1, 1909, pp.172-175,.