纳米CeO_2磨料在硅晶片化学机械抛光中的化学作用机制

Chemical Effect Mechanism in Chemical Mechanical Polishing Silicon Wafer Using Nano-sized CeO_2 Abrasives

通过分析化学机械抛光过程中软质层的形成及其作用过程,研究了使用纳米CeO2磨料进行化学机械抛光时化学作用的机制。分析表明,软质层是抛光液与硅晶片反应形成的一层覆盖在基体表面的腐蚀层,其硬度比基材小,厚度在几个纳米左右。软质层的存在一方面增大单个磨料的去除体积,增加材料去除速率;另一方面能减小磨料嵌入硅晶片基体的深度,这对于实现塑性磨削,降低抛光表面粗糙度,提高抛光质量,以及改善抛光效果都有着重要的作用。

The conception of the soft layer and its formation and effect on the surface roughness and material removal rate was proposed and studied. The results show that the soft layer is a reaction layer formed on the silicon surface ; it is softer than the silicon substrate and its thickness is about several nanometers. The existence of the soft layer can increase the material volume removed by one particle and the material removal rate during chemical mechanical polishing, and can decrease the cutting depth of the abrasive particle so as to realize ductile grinding. This contributes to decreasing the roughness of the polished surface and improving the polishing quality.