阴离子对铜化学机械抛光的影响

Effect of Anion on Copper Chemical Mechanical Polishing

在化学机械抛光过程中,抛光液的组成对抛光速率和表面质量有重要影响。利用自制抛光液,研究了在过硫酸铵体系抛光液中不同阴离子(硝酸根离子、溴离子、氯离子)对抛光速率的影响;采用动电位极化扫描技术对各抛光液在金属表面的成膜性能进行分析。结果表明,硝酸根离子的加入加快了阳极溶解反应,低浓度硝酸根离子的加入对抛光速率影响的波动性较大,随着浓度的增加抛光速率逐渐趋于初始值;随着氯离子(≥1mmol/L)或溴离子浓度的增加,抛光液的氧化性能降低,抛光速率不断降低;当溴离子浓度为0.1mmol/L时,Icorr值最小,抛光时对金属铜表面腐蚀程度较小。

In the process of the chemical mechanical polishing（CMP）,the composition of the polishing slurry has an important influence on the polishing rate and surface quality.Using the self-made polishing slurry,the effects of different anions（NO-3,Br-and Cl-） in the polishing slurry of ammonium persulfate system on the polishing rate were studied.The film-forming pro-perties of the polishing slurries on the metal surface were analyzed by dynamic potential polarization scanning technique.The results show that the addition of NO-3 enhances the anodic dissolution reaction,the removal rate becomes very fluctuant with the addition of lower concentrations of NO-3,and then reaches to the initial value with the increase of sodium nitrate.The oxidation ability of the polishing slurry decreases with increasing the concentration of Cl-（≥1 mmol/L） or Br-,which causes the decrease of removal rate.The minimal Icorr value is attained when the concentration of Br-is 0.1 mmol/L,and the corrosion on the surface of Cu is weaker in the process of CMP.