Removal-rate nonuniformity in chemical mechanical polishing is critical for the subsequent process. A theoretical model based on multipunches contact theory is proposed to calculate the contact-pressure distribution on the wafer with features with different pattern densities. The influence of pattern density on pressure distribution is investigated. Based on the model it is found that pattern density is a main factor in contact pressure distribution. The same pattern density has the same contact pressure despite the different width of pitch and high area. High-density areas have low contact pressure, while low density areas have a high pressure and thus, the removal-rate nonuniformity is caused. Effects of parameters of polishing process such as the downforce and pad properties on the nonuniformity of distribution of contact pressure are also studied based on the model. Low downforce and less pad compressibility bring small nonuniformity of contact pressure for the same features. The evolution of features profile with polishing time is calculated. (c) 2006 The Electrochemical Society.