微陽極導引電鍍法製作鎳銅合金微柱

Fabrication of Micrometer Ni-Cu Alloying Columns by Micro-Anode Guided Electroplating (MAGE)

本研究以微陽極導引電鍍法（Micro-anode guided electroplating, MAGE），探討在硫酸鹽、檸檬酸鹽兩種鍍浴中製作微鎳銅合金微柱之可行性，並在論文中，討論改變兩極偏壓、鍍浴中硫酸銅莫耳濃度等，對所得鎳銅合金微柱中鎳／銅組成之比例，與微柱形貌的影響。本實驗在硫酸鹽鍍浴中得不到鎳銅合金微柱；若在檸檬酸鹽鍍浴中，偏壓在4.2 V，兩極間距為10μm，所得微柱均為鎳銅合金成分。經由改變檸檬酸鹽鍍浴中的銅離子濃度以及使用之偏壓，均顯示對所得合金微柱形貌及組成均有極大影響：添加4 mM硫酸銅時所製得之合金微柱，表面平滑，且顆粒粗細均勻，一旦所添加之銅離子濃度超過8 mM，微柱表面開始不平整且有不均勻顆粒狀析出物；若銅離子濃度維持在4 mM，兩極偏壓逐漸由3.8 V、4.0 V、4.2 V增加至4.4 V，所得微柱中鎳／銅合金成份比例分別由75/25、80/20、83/17增加至87/13；若偏壓固定在3.8 V，銅離子濃度由4 mM、8 mM增加至12 mM，微柱中鎳／銅合金成份之比例則由75/25、59/41降低至49/51。顯然，合金微柱中鎳／銅成分比例隨著偏壓增大而增加，但隨著鍍浴中銅離子濃度增加而降低。

Micro-anode guided electroplating (MAGE) method was used to fabricate micrometer Ni-Cu alloying columns in sulfate and citrate baths. The bias employed for electroplating and the concentration of copper ions in the baths were variant to explore their influence on the composition and morphology of the micro-columns. The Ni-Cu alloying columns could only be fabricated in the citrate rather than in the sulfate. The Ni-Cu alloying micro-columns exhibit a smooth surface and they consist of uniform particles for those fabricated in the citrate using a bias of 4.2 V with a gap of 10 μm between the anode and the cathode. The composition and surface morphology of the micro-columns are determined by the bias employed in MAGE and the concentration of copper ions in the citrate. The alloying micro-columns resulted from the citrate containing 4 mM copper ions reveal a smooth surface that is consisted of uniform particles. An increase of copper ions from 4 to 8 mM, the micro-columns display a rough surface that is consisted of less uniform particles. Keeping the copper concentration at 4 mM to conduct MAGE with bias increasing from 3.8, 4.0, 4.2 to 4.4 V, we have fabricated alloying micro-columns with the ration of Ni/Cu increases from 75/25, 80/20, 83/17 to 87/13. On the other hand, the composition of the micro-columns decrease from 75/25、59/41 to 49/51 as the process performed at 3.8 V and the copper concentration increases from 4, to 8 and 12 mM in the citrate.