为确定苯并三唑(BTA)在铜的电解抛光液中的腐蚀抑制作用,研究铜在30%(质量分数)H3PO4+0.01 mol/L BTA抛光液中的电化学行为,测试铜在该抛光液中的极化曲线以及静态腐蚀量.应用原子力显微镜和能谱分析,观测不同阳极电势下静态腐蚀后的铜表面形貌并分析CuBTA膜的形成过程.结果表明,一定阳极电势范围下铜先行溶解,表面粗糙度加大,之后铜离子吸附BTA分子在表面逐渐形成CuBTA覆盖层,铜的溶解速度受到抑制,表面粗糙度稳定于一较低值.为保证CuBTA膜的形成,铜片所加的静态阳极电势应在0.5 V以下,本实验条件下形成稳定的CuBTA膜需要2 min.
To analyze the corrosive inhibition effects of BTA in phosphoric slurry for copper electrochemical mechanical polishing(ECMP),the electrochemical behavior of copper in 30% H3PO4 electrolyte with 0.01 mol/L benzotriazole(BTA) as an inhibitor was studied.The potentiodynamic polarization curves and the potentiostatic etching at different anodic potential of copper in the electrolyte were measured.The morphologies of the corroded workpieces were observed and the forming process of CuBTA surface film was analyzed by AFM and XPS.The results show that the surface roughness increases first with the dissolution of copper at a definite anodic potential range,then stabilizes at certain lower value owing to the dissolution inhibition effect of the Cu-BTA layer formed by adsorption of copper ions to BTA molecules.The anodic potential applied on copper should be kept below 0.5 V to sustain CuBTA film-formation,which takes near 2 min to stabilize at the test conditions.