Patent ID: 9263236
Filing Date: 2016-02-16
CPC Classification: C23C,H01J,H01L

Claim Text:
1. A system for monitoring a condition in an enclosed plasma processing space, comprising: (a) a sensor, arranged to be provided within said enclosed plasma processing space, for sensing a condition in said enclosed plasma processing space, the sensor being connected to an electronic circuit that comprises a modulation circuit; (b) the modulation circuit being arranged to modulate an output of said sensor onto a carrier signal to provide a modulated signal; (c) a first transmission line coupler arranged to be disposed within said enclosed plasma processing space, connected to said modulation circuit, and arranged to couple said modulated signal to a transmission line, said transmission line being arranged to deliver energy into said enclosed plasma space; (d) a second transmission line coupler arranged to be disposed outside said enclosed plasma processing space and coupled to said transmission line; (e) a demodulator connected to said second coupler for receiving and demodulating said modulated signal, wherein said carrier signal is generated by a first oscillator, and said electronic circuit further comprises a second oscillator whose frequency depends upon said condition sensed in said enclosed plasma processing space, wherein said modulation circuit is arranged to modulate said carrier signal with an output of said second oscillator.