Gas flow process control system and method using crystal microbalance(s)

Abstract

Disclosed are process control systems and methods incorporating a crystal microbalance (CM) (e.g., a quartz crystal microbalance (QCM)) into gas flow line(s) entering and/or exiting a processing chamber. A CM measures the resonance of a quartz crystal sensor contained therein as gas flows over that crystal sensor and can, thereby be used to accurately monitor, in real time, the mass flow rate of the gas. The mass flow rate may indicate that gas contamination has occurred and, in response, a controller can cause the gas flow to stop. Additionally, the mass flow rate may indicate the desired result will not be achieved within the processing chamber and, in response, advanced process control (APC) can be performed (e.g., the controller can adjust the gas flow). CM(s) incorporated into gas flow lines entering and/or exiting a processing chamber can provide precise measurements for process monitoring at minimal cost.