Multiple objective APC application for an oxide CMP process in a high volume production environment

Abstract

Presents three independent run-to-run APC controllers for the chemical-mechanical polishing (CMP). The controllers are applied to oxide polish processes in AMD's Fab30 to improve (a) the lot-to-lot variation, (b) to reduce the wafer-to-wafer variation and (c) to increase the wafer uniformity of the post-polish oxide thickness. Since different products and layers are processed on the same tools a method was introduced to compensate device and layer dependencies. The control algorithms were extended to a bi-layered polish process. Significant improvement was achieved for the individual controllers applied in the high volume production environment of Fab30 under the condition of a permanently changing product mix.