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Ru作为14 nm及以下技术节点的铜互连极大规模集成电路(GLSI)的新型阻挡层材料,在化学机械平坦化(CMP)工艺中易与Cu发生电偶腐蚀,影响器件的稳定性。采用动电位扫描的电化学方法表征铜钌表面的电化学反应,进而分析研究KIO4溶液的pH值和浓度对Cu/Ru电偶腐蚀的控制及机理。研究表明:pH值对Ru的腐蚀影响较大,溶液接近中性时,Ru表面会生成一层致密且不均匀的钝化膜,此时Ru表面腐蚀最小,腐蚀电流密度最低。随着KIO4浓度升高,Cu表面氧化膜加厚,阻碍化学反应的进行。当pH值为9、KIO4浓度为0.015 mol/L时,Cu/Ru腐蚀电位差由0.999 V降至0.628 V,实现了Cu/Ru电偶腐蚀的控制。
As a new type of barrier material of copper interconnect VLSI (GLSI) for 14 nm and below technology, Ru easily interfered with Cu in the chemical mechanical planarization (CMP) process and affected the stability of the device. The electrochemical reaction of Cu ruthenium on the surface of Cu ruthenium alloy was characterized by electrochemical method of potentiodynamic scanning. Then the control and mechanism of pH value and concentration of KIO4 solution on Cu / Ru galvanic corrosion were analyzed. The results show that pH has a great effect on the corrosion of Ru. When the solution is close to neutral, a dense and inhomogeneous passivation film is formed on the surface of Ru. In this case, Ru surface corrosion is the smallest and corrosion current density is the lowest. With the increase of KIO4 concentration, Cu oxide film thicker, hinder the chemical reaction. When the pH value is 9 and the concentration of KIO4 is 0.015 mol / L, the potential difference between Cu / Ru and Cu / Ru decreases from 0.999 V to 0.628 V, and the control of Cu / Ru galvanic corrosion is achieved.