碱性抛光液中H_2O_2对铜布线CMP的影响

化学机械平坦化(CMP)过程中,抛光液的化学作用对平坦化效果起着不可替代的作用。介绍了碱性抛光液中氧化剂(H2O2)对铜布线CMP的作用:H2O2对铜的强氧化性可以将铜氧化为离子状态,然后在螯合剂的螯合作用下快速去除铜膜;H2O2对铜的钝化作用可以保护凹处铜膜不被快速去除,从而有效降低高低差。此外,还研究了碱性抛光液中不同H2O2浓度对铜的静态腐蚀速率、动态去除速率及铜布线平坦化结果的影响。研究表明:抛光液对铜的静态腐蚀速率随H2O2浓度的增大逐渐降低然后趋于饱和;铜的动态去除速率随H2O2浓度的增大而逐渐降低;抛光液的平坦化能力随H2O2浓度的增大逐渐增强再趋于稳定。

Effect of H2O2 on the CMP of the Copper Pattern Wafer in the Alkaline Slurry

Polish slurry plays an irreplaceable role for the effect of the planarization in the process of the chemical-mechanical planarization(CMP).The effects of H2O2 on the CMP of the copper pattern wafer in the alkaline slurry were introduced.The strong oxidation to the copper of H2O2 can turn the copper into ionic condition,then the chelating function to copper of FA/O Ⅱ removes the copper film at a high rate of speed;the passivation to the copper of H2O2 can protect the lower copper film,and reduce the step height effectively.The impacts of different H2O2 concentrations on the static etching rate to the copper,the dynamic removal rate to the copper and the planarization results to the copper pattern wafer were also investigated.The investigations show that with the concentration of H2O2 increasing,the slurry’s static etching rate to the copper gradually reduces then tends to be saturated;the removal rate to the copper gradually reduces with the concentration of H2O2 increasing;the planarization ability gradually heightens and then tends to be stable with the concentration of H2O2 increasing.