An analytical model of effects of 2-D pad surface textures on contact pressure distribution during CMP

In order to model the effects of pad asperities on the polishing process, an analytical way to calculate the contact pressure between wafer and pad is given in this paper. The contact pressure based on a 2-D analytical model is compared with the numerical results which are obtained by finite element method (FEM). When the wafer surface contacts only several asperities of the pad textures and the distances between the asperities are small, the ignorance of the interaction of the contact asperities will bring differences between the analytical result and the numerical result. When the pad textures contact completely with wafer surface, the analytical result fit the simulation data very well.