Integrated multiscale three-dimensional simulation approach in local interconnect gap-fill optimization

An integrated three-dimensional (3D) simulation approach for the optimizati on of multistep process modules is developed. A link between a 3D finite vo lume reactor-scale model and a developed 3D cell topography feature-scale m odel allows the prediction of uniformity distribution for a sequence of pro cess steps on an entire wafer surface. As an example, an across-wafer gap-f ill is simulated using a combination of simulation tools to capture a varie ty of nonuniformities that exist in all steps involved in the local interco nnect tungsten-fill process flow. Across-wafer variations in Ti flux densit y, angular distributions in Ti and TiN physical vapor deposition fluxes, as well as nonuniformities in precursor fluxes in TiN and W chemical vapor de position are taken into consideration. Across wafer blanket layer thickness variations as well as bottom and sidewall thickness variations inside inte rconnect features are determined for all deposited layers. Across-wafer met al stack thickness distributions, wafer edge effect, and key-hole formation inside the features are simulated. Experimentally extracted parameters are employed for the calibration of the simulation results. (C) 2001 American Vacuum Society.