一种基于非晶层粘性流动的机械化学抛光模型

A Chemical Mechanical Polishing Model Based on the Viscous Flow of the Amorphous Layer

通过分析单个微纳米磨粒滑动接触的分子动力学模拟的研究结果,提出了在典型的机械化学抛光(CMP)过程中芯片表面材料的去除应为表面非晶层物质粘性流动所致的新观点。基于这种机理,应用微观接触力学和磨粒粒度分布理论建立了一种新的表征CMP过程材料去除速率的数学模型。模型中引入了一个表征单个磨粒去除芯片表面非晶层能力的比例系数k,k综合反映了磨粒的机械作用、抛光液对芯片表面的化学作用和芯片的材料特性。通过实验验证发现该模型的理论预测值与实验测定值十分吻合。

Based on the theoretical analysis of the molecular dynamics simulation of sliding contact between a single micro-particle and a smooth flat surface, a new dominant mechanism for the material removal in chemical mechanical polishing （CMP） process, i.e. viscous flow of the amorphous layer on wafer surface, was proposed. Based on this mechanism, a new mathematical model characterizing the material removal rate in CMP process was developed by using micro-contact mechanics and particle size distribution theory. Particularly,a new important parameter k, which represents the ability to remove the amorphous layer on wafer surface by a single particle and reflects the mechanical and chemical synergetic action in CMP process in terms of change in hardness and composition of wafer surface material, was firstly put forward and integrated in the model. It is found that the removal rates predicted by the model are in good agreement with those experimentally measured under the same CMP conditions.