Device dependent control of chemical-mechanical polishing of dielectric films

This paper presents a control scheme for run-to-run control of chemical-mechanical polishing (CMP). The control scheme tracks both device pattern dependent and equipment induced disturbances. The structure of the controller is such that sensitivity to qual (unpatterned blanket oxide) wafer frequency is minimized. Additionally, prethickness variation and metrology delay are accounted for in the design. Results from applying this scheme in volume production are presented.