Arrangement For Plasma Processing System Control Based On RF Voltage

摘要

An arrangement for controlling a plasma processing system is provided. The arrangement includes an RF sensing mechanism for obtaining an RF voltage signal. The arrangement also includes a voltage probe coupled to the RF sensing mechanism to facilitate acquisition of the signal while reducing perturbation of RF power driving a plasma in the plasma processing system. The arrangement further includes a signal processing arrangement configured for receiving the signal, split the voltage signals into a plurality of channels, convert the signals into a plurality of direct current (DC) signals, convert the DC signals into digital signals and process the digital signal in a digital domain to generate a transfer function output. The arrangement moreover includes an ESC power supply subsystem configured to receive the transfer function output as a feedback signal to control the plasma processing system.

主权项

1. An arrangement for controlling a plasma processing system that includes a plasma processing chamber, the arrangement comprising:
a radio frequency (RF) sensing mechanism, said RF sensing mechanism is proximate to a non-plasma exposing component of an electrostatic chuck (ESC) disposed within the plasma processing system, to obtain an RF voltage signal; a voltage probe coupled to said RF sensing mechanism to facilitate acquisition of said RF voltage signal while reducing perturbation of RF power driving a plasma in said plasma processing system; a signal processing arrangement including,
an anti-aliasing filter to filter RF voltage signal received from the voltage probe;a RF splitter to split the filtered RF voltage signal into a plurality of channels and to convert the RF voltage signal for each of the plurality of channels into a corresponding direct current (DC) signal;an analog-to-digital converter (ADC) to convert the DC signal of each of the plurality of channels in a digital domain to a corresponding digital signal;a digital processing block to process the digital signals within the digital domain, wherein the process includes,(a) filtering the digital signals, wherein the filtering includes detecting a peak voltage of each frequency of the plurality of channels and peak voltage of a composite broadband signal;(b) calibrating each of the plurality of digital signals;(c) computing a transfer function using the digital signals as input to obtain a transfer function output, the transfer function output accounting for contribution of frequency of each of the plurality of channels of the RF voltage signal in wafer bias; andan ESC power supply subsystem configured to receive said transfer function output as a feedback signal to control said plasma processing system.