銅／鉭金屬於化學－機械拋光過程中之伽凡尼腐蝕之研究

Galvanic Corrosion of Cu / Ta during Chemical-Mechanical Polishing

本研究主要探討銅和鉭在靜止狀態下或是化學-機械拋光（CMP）過程中於硝酸鐵研磨液中之伽凡尼腐蝕現象。由開路電位和伽凡尼電流的量測結果可以得知：在電流或是電位值不再明顯變化的情形下，銅和鉭等面積時，不論是在靜止或是研磨狀態，銅為陽極而鉭為陰極。但若在研磨初期，則有銅鉭陰陽極互換的現象發生。當鉭面積縮小為銅面積之四分之一時，在靜止狀態下，伽凡尼電流值亦降為四分之一。而在研磨狀態下，因鉭面積縮小不利於氧化鉭的生成，導致銅和鉭的極性與銅和鉭等面積時相反。此外，由XPS的分析結果可知：在硝酸鐵溶液中，銅表面會生成Cu0和Cu(OH)2；而鉭表面會生成Ta2O5。

This study focused on the galvanic corrosion between Cu and Ta in iron nitrate slurry under static or chemical-mechanical polishing (CMP) conditions. From the results of the open circuit potential and the galvanic current measurements, under no obvious change on open circuit potentials or galvanic currents conditions, while the areas of Cu and Ta were equal, whether in static or CMP conditions, Cu was anode and Ta was cathode. However, at the forepart of CMP, the exchange of anode and cathode on Cu and Ta occurred. When the area of Ta was shrunk to onefourth area of Cu, under static condition, the galvanic current also decreased to one-fourth. Moreover, under CMP condition, the polarity of Cu and Ta would exchange due to Ta2O5 not easy to form on Ta surface because of the area of Ta being shrunk. Finally, according to the XPS results, in iron nitrate solution, CuO and Cu(OH)2 would form on Cu surface and Ta2O5 would form on Ta surface.