纳米磨料对硅晶片的超精密抛光研究

采用均相沉淀法制备了纳米CeO2和纳米Al2O3超细粉体,将所制备的超细粉体配制成抛光液并用于硅晶片化学机械抛光,考察了纳米磨料对硅晶片抛光效果及抛光机理的影响.结果表明,纳米CeO2磨料的抛光效果优于纳米Al2O3磨料,采用纳米CeO2磨料抛光硅晶片时可以得到在1μm×1μm范围内微观表面粗糙度Ra为0.089nm的超光滑表面,且表面微观起伏较小.

Study on Ultra-Precision Polishing of Silicon Wafer by Nanosized Abrasives

Nanoscale powders of CeO_2 and Al_2O_3 were prepared via homogenous precipitation method. The polishing slurry for the chemical-mechanical-polishing of silicon wafer was prepared from the resulting nano-particulates, keeping the mass fraction of the nano-particulates therein as 1%. Thus the polishing tests with respect to the single crystal Si wafers in the presence of the polishing slurry containing the nano-particulates were carried out to investigate the polishing effect. The morphologies and surfaces roughness of the polished Si wafers were observed and determined on an atomic force microscope. It was found that the nano-CeO_2 was superior to nano-Al_2O_3 in terms of the ability to reach ultra-precise polishing of the Si wafers, which could be related to the relatively smaller hardness of the former and its decreased damage to the polished Si wafer surface. It was feasible to realize ultra-precise polishing of the single crystal Si wafers making use of the polishing slurry doped with the nano-particulates, because in this case the cutting depth of the nano-sized abrasives was minimized, the removal of material was dominated by plastic flowage, and the polished surface quality and polishing efficiency could be assured.