An Approach to Modeling Particle-Based and Contact-Based Wear in CMP

Abstract

ABSTRACTA volume-pixel, or “voxel”-based wear model was developed in order to predict feature-scale wear in chemical-mechanical polishing (CMP), and was compared to the measured evolution of lithographically-patterned features during full-scale CMP tests. In order to conduct this study, a lithographic technique was used in order to pattern a set of raised square features into Cu-coated silicon wafers. A two-dimensional (2D) contact profilometer was used to measure the topography of an isolated feature on the wafer both before polishing and at various intervals throughout the polishing process. For wear modeling, the voxel modeling framework involved the conversion of each of the pre-polished feature topographies into a square matrix of cuboids, which allowed for contact mechanics and wear modeling to take place between the interacting cuboids of the sample and a simulated polishing pad. After the predicted wear of the Cu feature was then compared to experiment.