锇在醋酸体系抛光液中化学机械抛光研究

Investigation on chemical mechanical polishing of osmium with CH_3COOH-based slurry

锇有可能作为大规模集成电路铜互连扩散阻挡层新材料。本研究利用自制的醋酸体系抛光液对金属锇片进行抛光,研究了双氧水(H2O2)、醋酸(CH3COOH)和苯丙三氮唑(BTA)对腐蚀效果的影响。结果表明,CH3COOH能够在抛光液中起到酸剂、络合剂和抑制剂的作用;在CH3COOH体系抛光液中,H2O2主要通过促进阴极反应的进行从而增强抛光液对金属锇的化学作用,H2O2浓度的增加虽然提高了对金属锇化学腐蚀的能力,但不利于金属表面钝化膜的形成;BTA的加入促进金属锇表面钝化膜的生成,因此降低了腐蚀电流,且金属锇表面钝化膜的厚度随BTA浓度的增加而增加。

Osmium(Os) may be used as new barrier material in copper interconnects of ultra-large scale integration.In this work,Os disk was polished with self-made CH3COOH-based slurry,the effect of H2O2,CH3COOH and BTA on the corrosion behaviours was investigated.It was found that,CH3COOH played a role of pH adjusting agent,complexing agent and inhibitor in the slurry;In CH3COOH-based slurry,H2O2 could enhance the chemical action of the slurry on the surface of Os through accelerating the cathode reaction;The increasing of H2O2 concentration promoted the chemical corrosion ability to the surface of Os,but inhibited the formation of passive film;The addition of BTA decreased the value of Icorr,possibly due to the presence of the passive film;The thickness of the passive film increased with the increase of BTA concentration.