本研究採用微陽極導引專利電鍍法來製備直徑約50 微米之銅 柱。在硫酸銅鍍液中(硫酸銅200g/l，硫酸65g/l 及35g/l, 鹽酸1ml)， 控制微陽極(白金線直徑125 微米)以間歇運動自陰極(1 公分見方之鍍 銅矽晶片)表面向上移動10 微米，在適當偏壓下進行微電鍍研究。微 銅柱之表面形貌以掃描式電子顯微鏡進行觀察，結果發現: 銅柱形貌 受兩極偏壓大小影響極大。偏壓為2.6V 時，銅柱的表面平滑柱徑平 均; 偏壓為3.2V 時，銅柱表面凹凸不平外觀如珊瑚狀。兩極間距越小 (1 微米)，微銅柱柱徑較小表面較不平整會有節狀出現，兩極間距越 大(40 微米)，微銅柱表面較平整但柱徑較大。固定兩電極間距200μ m 下，利用電化學交流組抗頻譜儀測試來探討微電鍍行為，發現當兩 極偏壓由0.615V(OCP)升至0.773V 時，此偏壓範圍為活性極化，此 時銅已還開始析出，而0.773 至1.1V 為銅之擴散極化，若偏壓繼續 提高超過1.1V，電容與極化電阻值減小，銅與氫氣析出在銅基材上。 實用上銅柱析鍍之電位選擇從2.6V 至3.2V，此乃因小於2.6V 銅柱 析渡速率太慢，若兩極偏壓高於3.2V，則生成之銅柱外貌粗糙且無 法掌控外形，因此不符實際需要。本研究依據實驗結果歸納出微銅柱 製作之最佳條件，並提出微電鍍之反應機制，並應用微陽極導引電鍍 來製作銅柵欄。 Micrometer copper columns (roughly 50µm in diameter) were fabricated by a patented process named as micro anode guided electroplating (MAGE). In this process, a micro anode (made of Pt wire 125µm in diameter) was controlled to depart from the cathode intermittently (1×1 cm2 silicon coated with 1.8µm copper) under optimed biases to fabricate copper micro-columns in an acidic CuSO4 bath(CuSO4． 5H2O 200g/l，H2SO4 65g/l and 35g/l, HCl 1ml). The surface morphologies of the copper micro columns, examined by scanning electron microscopy (SEM), depended on the bias applied between the electrodes. The microcolumn obtained at a bias of 2.6V, displayed uniform diameter and smooth surface. In contrast, the micro column fabricated at a bias of 3.2V was coralline and displayed rough surface. The sem morphology of microcolumns was also influenced by the gap in each intermittent step. A short gap (e.g. 1µm) led to nodose microcolumn with rough surface but a long gap (e.g. 40µm) led to uniform microcolumn with smooth surface. The nodose microcolumn exhibited a smaller diameter (1µm) than the uniform one (40µm). Electrochemical impedance spectroscopy (EIS) was conducted to explore the MAGE process. As the bias beyond 0.615V, the copper deposited. The range of bias from 0.615V(ocp) to 0.773V was the activation polarization of copper and 0.773V to 1.1V was concerntration polarization. As the bias beyond 1.1V, the data of both C and Rp decreased with increasing the bias, copper and hytroden found to deposition on the substrate. In this work, practical range of bias was chosen from 2.6 to 3.2V because the growth rate of the microcolumn was to slow under biases less than 2.6V, and coralline microcolumn was not acceptable under biases greater than 3.2V. In comparison with the microcolumns fabricated in various conditions, we obtained the optimal conditions to attain the qualified copper microcolumns. The mechanism of the MAGE process is discussed on bias of the EIS study. A row of four copper micrometer columns was successfully fabricated.
