单烷基磷酸酯钾盐抑制剂对Co互连化学机械抛光的影响

The Effect of Potassium Monoalkyl Phosphate Ester Inhibitor on Chemical Mechanical Polishing of Co Interconnects

针对抛光液中传统抑制剂如苯丙三氮唑(BTA)等具有毒性,会污染环境等问题,以SiO2为磨料,在甘氨酸-双氧水体系下,使用单烷基磷酸酯钾盐(MAPK)作为新型抑制剂制备Co互连粗抛抛光液,通过抛光和静态腐蚀实验和电化学、光电子能谱、接触角分析等表征方式揭示MAPK在化学机械抛光(CMP)中对Co表面质量的改善以及对Co的抑制机制。结果表明:MAPK通过物理吸附和化学吸附方式在Co表面形成的致密钝化膜,可以很好地抑制Co的腐蚀,从而可以在较低的静态腐蚀速率下获取较高的去除速率;加入MAPK可以提高抛光液的润湿性,能够显著改善Co互连抛光后的表面质量,使Co的去除速率大于500 nm/min,静态腐蚀速率小于1 nm/min,表面粗糙度小于0.5 nm。

In response to the toxicity and environmental pollution caused by traditional inhibitors in polishing slurry such as benzotriazole(BTA),a Co interconnect rough polishing slurry was prepred using SiO 2 as an abrasive and potassium monoalkyl phosphate ester(MAPK)as a new inhibitor in a glycine hydrogen peroxide system.Through polishing and static corrosion experiments,as well as characterization methods such as electrochemistry,photoelectron spectroscopy,and contact angle analysis,the improvement of MAPK on Co surface and the inhibition mechanism of Co in chemical mechanical polishing(CMP)were revealed.The results indicate that MAPK forms a dense passive film on the surface of Co through physical and chemical adsorption,which can effectively inhibit the corrosion of Co and achieve higher removal rates at lower static corrosion rates.The addition of MAPK can improve the wettability of the polishing slurry and significantly improve the surface quality of Co interconnect polishing,resulting in a Co removal rate greater than 500 nm/min,a static corrosion rate less than 1 nm/min,and a surface roughness less than 0.5 nm.