Methods and systems for focus ring thickness determinations and feedback control

Abstract

Methods and systems are disclosed for focus ring thickness measurement and feedback control within process chambers. For disclosed embodiments, in-chamber sensors measure physical parameters associated with focus rings, and these measurements are used to determine thickness for the focus rings. The thickness determinations can be used to detect when a focus ring should be replaced and can also be used as feedback to adjust the position of the focus rings within the chamber. For one embodiment, measurements from ultrasonic sensors are used to make thickness determinations for focus rings. For further embodiments, these ultrasonic sensors are positioned at end portions of focus ring lift pins. Other sensors can also be used such as capacitive sensors, resistive sensors, and/or other desired sensors. Further variations and implementations can also be achieved using in-chambers sensors to facilitate focus ring thickness determinations.