Modeling of Wafer Topography's Effect on Chemical–Mechanical Polishing Process

Topography on the wafer surface has a great effect on chemical-mechanical polishing (CMP). In this paper, the performance of a CMP system is demonstrated to be approximately an linear time invariant (LTI) system. The effects of the low-frequency components and high-frequency components in the wafer topography on CMP process are investigated. The magnitude spectra and phase spectra of the system are obtained. A model for the effect of more complex topography is established based on Fourier transform. The influences of down force and pad stiffness on the performance of CMP with the same topography are also studied.