Effluent impedance based endpoint detection

Abstract

A system to measure an impedance of an effluent associated with a foreline (effluent line or exhaust) is provided. This system includes a remote plasma source, a process chamber, an effluent line, an electrode assembly, an RF driver, and a detector. The remote plasma source couples to the process chambers and is operable to supply chamber-cleaning gas to the process chamber. The effluent line also couples to the process chamber where chamber-cleaning effluent exhausts the process chamber via the effluent line. The electrode assembly, located in the effluent line, is exposed to the effluent exhausting from the process chamber. The electrode assembly, coupled to the RF driver, receives an RF signal from the RF driver. The RF signal applied to the electrode assembly induces a plasma discharge within the electrode assembly and effluent line. A detector coupled to the electrode assembly detects an end point of a chamber clean of the process chamber. The end point may be detected based on a change in impedance associated with the plasma discharge within the electrode assembly and effluent line.

Dependencies are inferred from the claim text.