GSI多层铜布线化学机械平坦化速率一致性

Chemical Mechanical Planarization Uniformity of Multilayer Copper Pattern Wafers for GSI

采用自主研发的碱性铜布线抛光液,在300 mm化学机械平坦化平台上对铜镀膜去除速率一致性进行了实验研究,并对质量传递和速率一致性的关系进行了深入分析。研究结果表明,压力和流量变化对不同的抛光液影响不同。低压CMP下全局质量传递差较小,去除速率一致性好。随着压力的增大,铜的平均去除速率迅速增大;而压力的增大使晶圆中心和边缘处质量传递差增大,铜的去除速率差增大,导致去除速率一致性劣化。流量的增大利于提高全局去除速率一致性,并使全局质量传递加快,铜去除速率略有增大。该研究成果对提高300 mm铜布线片CMP全局平坦化,尤其是提高器件成品率和优品率有一定的指导意义。

The experimental investigation of the removal rate uniformity for the copper films was performed on the 300 mm chemical mechanical planarization （CMP） platform by using the self made alkaline copper slurry. Besides that, the in-depth analysis of the relationship between the mass transfer and removal rate uniformity was made. The result shows that the variation of the pressure and flow rate has different effects on different slurries, when the pressure is low, the overall mass transfer difference is minimized between the center and edge of the wafer, which is helpful for achieving a good removal rate uniformity. As the pressure increases, the average re- moval rate of Cu significantly increases, however, it will cause a poor removal rate uniformity due to different removal rates between the center and edge of the wafer. In addition, the result also shows that the increase of the slurry flow rate is beneficial for the improvement of the overall removal rate uniformity and also improves the overall mass transfer, and the removal rate of Cu increases slightly. The research results have a guiding significance for the improvement of the over- all uniformity of 300 mm Cu pattern wafer CMP, especially play an important role for the improvement of a high yield and optimal product rate.