An analytical model of multilevel ILD thickness variation induced by the interaction of layout pattern and CMP process

In this paper, an analytical model for Chemical Mechanical Polishing (CMP) is proposed. This model relates the physical parameters of the CMP process to the in-die variation of Inter-Layer Dielectric (ILD) in the multilevel metal process. The physical parameters considered in this model include the deposited ILD profile, deformation of the polishing pad and the hydrodynamic pressure of slurry flow. We demonstrate a fit with sample data at the die level of a state-of-the-art microprocessor.