利用复合磨粒抛光液的硅片化学机械抛光

Chemical mechanical polishing for silicon wafer by composite abrasive slurry

为了提高硅片的抛光速率,利用复合磨粒抛光液对硅片进行化学机械抛光。分析了SiO2磨粒与聚苯乙烯粒子在溶液中的ζ电位及粒子间的相互作用机制,观察到SiO2磨粒吸附在聚苯乙烯及某种氨基树脂粒子表面的现象。通过向单一磨粒抛光液中加入聚合物粒子的方法获得了复合磨粒抛光液。对硅片传统化学机械抛光与利用复合磨粒抛光液的化学机械抛光进行了抛光性能研究,提出了利用复合磨粒抛光液的化学机械抛光技术的材料去除机理,并分析了抛光工艺参数对抛光速率的影响。实验结果显示,利用单一SiO2磨料抛光液对硅片进行抛光的抛光速率为180nm/min;利用SiO2磨料与聚苯乙烯粒子或某氨基树脂粒子形成的复合磨粒抛光液对硅片进行抛光的抛光速率分别为273nm/min和324nm/min。结果表明,利用复合磨粒抛光液对硅片进行抛光提高了抛光速率,并可获得Ra为0.2nm的光滑表面。

In order to increase the polishing rate for a silicon wafer,the composite abrasive slurry was used in Chemical Mechanical Polishing（CMP）. Zeta potentials of silica abrasives and polystyrene particles in the slurry were measured at various pH values, and the mechanism of interactions between silica abrasives and polymer particles was analyzed. Small silica abrasives were observed to attach onto the surfaces of the polystyrene particles and some resin particles. Then,the composite abrasive slurry was obtained by adding some polymer particles into single abrasive slurry. In comparison with the polishing performance of traditional CMP and CMP using composite abrasive slurry, the mechanism of material removal of CMP using composite abrasive slurry was proposed, and the influence of craft parameters on the polishing rate was studied through the experiments. Experimental results indicate that the polishing rate is 180 nm/min with single silica abrasive slurry, and 273 nm/min, 324 nm/min with the silica abrasive/polystyrene particle composite slurry and silica abrasive/ resin particle composite slurry respectively. These data show that the removal rate with composite abrasive slurry is improved significantly and the wafer surface roughness Ra is 0.2 nm.