本研究主要探討銅在磷酸中之電化學平坦化機制，利用陽極極化曲線與交流阻抗分析，比較調整磷酸系統之物化特性對於拋光效果之影響。經極化曲線分析後可找出適合進行銅電解拋光之電位範圍，再藉由交流阻抗分析找出符合電化學平坦化機制之等效電路以及其電阻、電容等參數。利用光學顯微鏡、原子力顯微鏡、掃描式電子顯微鏡等影像圖作為拋光前後表面型態之分析與比較。調整磷酸濃度與溶液組成，综合陽極極化曲線與交流阻抗分析的結果，發現在極限電流之電位範圍下，85wt.% 磷酸有最好之拋光效果，其表面粗糙度可由拋光前之32 nm降至1.4nm；在65wt.% 磷酸中進行拋光，並改變溶液之酸鹼值、導電度、黏度等物理、化學性質，實驗結果顯示含水量越低、黏度高，拋光效果越好；拋光後並可發現鹽膜生成。最後，本研究根據拋光期間的電化學特性以及表面與整體溶液間的性質變化，提出了一整合鹽膜與接受子理論的電化學平坦化機制。 Electrochemical planarization mechanism of copper in phosphoric acid was studied by using anodic polarization and AC impedance analysis. Several properties were changed in phosphoric acid system, and the experimental results were compared to discuss the polishing effect and mechanism. Polarization curve can be suitable for copper to find out the potential range of electropolishing. The optimum equivalent circuit was found to fit impedance results and could illustrate electrochemical planarization mechanism well. Optical microscope, atomic force microscopy, and scanning electron microscope were used to analyze the surface profiles before and after polishing. It was found that under the potential range in limiting current, copper electropolishing in 85wt.% phosphoric acid could obtain the best performance. The surface roughness before polishing was 32 nm and decreased to 1.4 nm after polishing. The effects of pH values, conductivity, viscosity and other properties on copper electrolysis in 65wt.% phosphoric acid were investigated. The experimental results showed that low water content and high viscosity would obtain the good polishing performance. In addition, salt film was found and examined after polishing. According to electrochemical characteristics of copper in phosphoric acid, an integrated electrochemical planarization mechanism is proposed, and the relation between copper electropolishing and phosphoric acid is reported.
