Integration of feedback control and run-to-run control for plasma enhanced atomic layer deposition of hafnium oxide thin films

Abstract

Facilitated by the increasing importance and demand of semiconductors for the smartphone and even the automobile industry, the plasma-enhanced atomic layer deposition (PEALD) has gained tremendous industrial interest as it offers a way to efficiently deposit thin-films with ultra-high conformity. A series of studies have been carried out to elucidate the mechanisms and the concept of the PEALD process. Despite the great deal of research effort, PEALD processes have not been fully characterized from the view point of process control. This study aims to use a previously developed multiscale computational fluid dynamics (CFD) simulation model to design and evaluate an optimized control scheme to deal with industrially-relevant disturbances. Specifically, an integrated control scheme using a proportional-integral (PI) controller and a run-to-run (R2R) controller is proposed and evaluated to ensure the deposition of high-quality conformal thin-films. The PEALD process under typical disturbances is simulated using the multiscale CFD model, and the integrated controller is applied in the process domain. Using the controller parameters determined from the open-loop results, the developed integrated PI-R2R controller successfully mitigates the disturbances in the operating pressure and the gas bubbler temperature with the combined effort of both controllers.