Modeling of chemical-mechanical polishing on patterned wafers as part of integrated topography process simulation

The simulation of chemical-mechanical polishing (CMP) is particularly important within integrated topography process simulation environments to allow for studying the interplay between etching, deposition, and CMP process steps. In this work, a feature-scale physical model based on contact mechanics has been implemented in 2D. The model takes into account both the roughness and elastic deformation of the polishing pad for computing the pressure distribution. This pressure distribution is used to determine the local removal rate using the Preston equation. Our simulator allows for two-step polishing of multi-line structures with different pads, slurries and polishing parameters. The data format used is supported by a standard software environment (ISE TCAD) which therefore allows for coupling of our topography simulation modules with various tools such as process simulators and modules for electrical characterization. The integration of our simulator with the 3D simulation of barrier and copper deposition is demonstrated for two damascene processes.