CMP profile simulation using an elastic model based on nonlinear contact analysis

Recently, simulation of Chemical Mechanical Polishing (CMP) is becoming more important because planarity and uniformity which are dependent on many dynamic factors are difficult to control. In this paper, a profile simulation environment based on the linear elastic material and nonlinear contact analysis that considers equipment parameters, such as pad hardness, thickness and down pressure is presented. In transient CMP simulation using the elastic model, the contact stress on the wafer surface is the dominant factor in polishing rate during the CMP process. The profiles of CMP simulation agree well with the measured data. This simulation can be used to optimize the CMP process and to generate design rules for filling dummy patterns which are used to improve planarity.