Rf generator and its operating method

Abstract

Disclosed herein is an RF generator that includes an inverter including first and second switching elements controlled by a PWM control signal and converting a DC voltage having a predetermined level outputted from the DC/DC converter into an AC voltage having a predetermined level, an LC filter that outputs a sine wave resonance signal having a predetermined resonance frequency from a high frequency signal, a transformer that induces a high frequency power signal of a pulse waveform outputted from the LC filter to a secondary side, an ignition module that sets a switching frequency at the termination of an ignition mode as an ignition mode escape frequency, an operation module that applies the ignition mode escape frequency as an initial value of a switching frequency in an operation mode, and a signal controller that generates the PWM control signal by using the switching frequency.

1 . An RF generator providing a high frequency power signal to a plasma chamber as a capacitive load, the RF generator comprising:
 a rectifier configured to rectify an AC voltage of a commercial power supply into a DC voltage and output the DC voltage;   a DC/DC converter configured to convert the DC voltage outputted from the rectifier into a second DC voltage;   an inverter including first and second switching elements controlled by a PWM control signal and operating alternately, and configured to convert a DC voltage having a predetermined level outputted from the DC/DC converter into an AC voltage having a predetermined level;   an LC filter including an inductor and capacitors coupled in series and parallel at an output terminal of the inverter, and configured to output a sine wave resonance signal having a predetermined resonance frequency from a high frequency signal outputted from the inverter;   a transformer configured to induce the high frequency power signal of a pulse waveform outputted from the LC filter to a secondary side;   a signal controller configured to generate the PWM control signal by using a high frequency load detection current and a high frequency load detection voltage of the plasma chamber; and   a ringing removal unit connected in parallel to the secondary side of the transformer, and configured to remove a ringing phenomenon occurring in a high frequency load current waveform due to a resonance phenomenon of a leakage inductance component existing on the secondary side of the transformer and a parasitic capacitance component parasitic to the plasma chamber as the capacitive load,   wherein the ringing removal unit includes a capacitor.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The RF generator of  claim 1 , wherein the ringing removal unit is composed of a resistor and a capacitor connected in series. 
     
     
         5 . The RF generator of  claim 1 , wherein the signal controller receives the high frequency load detection current and outputs a state signal to display a state of the high frequency load detection current, and
 the RF generator further comprises:   an indicator configured to display the state of the high frequency load detection current in response to the state signal.