A Simple Adaptive Optimization Algorithm for the Tungsten LPCVD Process

In this paper, a reduced order, physically-motivated empirical model is proposed and validated via simulation for the single wafer tungsten low pressure chemical vapor deposition (LPCVD) processing step. The so-called multiple response surface method is adopted to describe the spatial deposition nonuniformity across a wafer surface. Based on this modeling methodology, a simple adaptive optimization control strategy is developed by which the average deposition thickness at the wafer surface is controlled to a desired level while its variation of the state across the wafer surface is minimized. Simulation results demonstrate the effectiveness of the control strategy and its potential capability of rejecting disturbances during the process. In this study, a simulation platform (CFDSWR) is used to represent the single wafer tungsten LPCVD process. The control strategy introduced here is quite general and applicable to other processing steps as well