Plasma processing apparatus

Abstract

There is provided a method for driving a member provided in a processing chamber. The method includes irradiating to the member measurement light having a wavelength that penetrates the member, detecting intensity distribution of reflected light based on reflected light from an upper surface of the member and reflected light from a bottom surface of the member, calculating an optical path difference by applying Fourier transform to a spectrum indicating the intensity distribution, and determining a driving amount of the member based on the optical path difference. The method further includes driving the member based on the determined driving amount.

1 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a substrate support provided in the plasma processing chamber;   an annular member provided in the plasma processing chamber;   an actuator configured to move the annular member in up and down direction with regard to the substrate support;   an irradiator configured to irradiate measurement light to the annular member;   a detector configured to detect an intensity distribution of reflected light based on reflected light from an upper surface of the annular member and reflected light from a bottom surface of the annular member;   an analyzer configured to calculate an optical path difference by applying Fourier transform to a spectrum representing the intensity distribution, and determine a driving amount of the annular member based on the optical path difference; and   a controller configured to control the actuator based on the determined driving amount.   
     
     
         2 . The plasma processing apparatus of  claim 1 ,
 wherein the annular member is at least one of an edge ring, a cover ring disposed around the edge ring, an insulator ring disposed below the cover ring, and a top shield ring disposed around an upper electrode facing the substrate support.   
     
     
         3 . The plasma processing apparatus of  claim 1 ,
 wherein the annular member is disposed on the substrate support.   
     
     
         4 . The plasma processing apparatus of  claim 2 ,
 wherein the annular member comprises a plurality of segments; and   the actuator drives at least one of the plurality of segments based on the determined driving amount.   
     
     
         5 . The plasma processing apparatus of  claim 1 ,
 wherein the irradiator irradiates the measurement light to multiple portions of the annular member;   the detector detects an intensity distribution of reflected light at each of the multiple portions of the annular member based on reflected light from an upper surface of each of the multiple portion of the annular member and reflected light from a bottom surface of each of the multiple portion of the annular member; and   the analyzer calculates an optical path difference at each of the multiple portions by applying Fourier transform to a spectrum representing the detected intensity distribution of the reflected light at each of the multiple portion, and determines a driving amount of the annular member at each of the multiple portions based on the optical path difference at each of the multiple portions.   
     
     
         6 . The plasma processing apparatus of  claim 5 , further comprising:
 multiple lifter pins provided to be in contact with the annular member;   wherein the actuator drives individually at least one of the multiple lifter pins corresponding to the respective multiple portions based on the determined driving amount of the annular member at each of the multiple portions.   
     
     
         7 . The plasma processing apparatus of  claim 1 ,
 wherein the irradiator irradiates the measurement light to another member different from the annular member provided in the processing chamber; and   the actuator drives the another member based on a determined driving amount of the another member.   
     
     
         8 . The plasma processing apparatus of  claim 5 ,
 wherein irradiator irradiates the measurement light to another member different from the annular member provided in the processing chamber, and the measurement light is irradiated to multiple portions of the another member; and   the actuator drives the another member based on a determined driving amount of the another member at each of the multiple portions of the another member.   
     
     
         9 . The plasma processing apparatus of  claim 1 ,
 wherein the irradiator irradiates the measurement light to an upper portion or a bottom portion of the annular member.   
     
     
         10 . A plasma processing apparatus comprising:
 a plasma processing chamber;   an annular member provided in the plasma processing chamber;   an actuator configured to move the annular member vertically;   a controller; and   a measurement system including a light source, an optical circulator, a focuser, a spectroscope and an analyzer;   wherein the focuser is configured to emit measurement light received through the optical circulator from the light source, and enter reflected light comprising first reflected light from an upper surface of the annular member and second reflected light from a bottom surface of the annular member;   the spectroscope is configured to receive the reflected light comprising the first reflected light and the second reflected light, and measure a spectrum of the reflected light;   the analyzer is configured to determine a driving amount of the annular member based on the measured spectrum of the reflected light, and   the controller is configured to control the actuator based on the determined driving amount.   
     
     
         11 . The plasma processing apparatus of  claim 10 ,
 wherein the spectroscope includes a light dispersion element dispersing light at a predetermined dispersion angle for each wavelength and a light receiving part receiving the light dispersed by the light dispersion element.   
     
     
         12 . The plasma processing apparatus of  claim 11 ,
 wherein the light receiving part is a Charge Coupled Device (CCD) in which multiple light receiving elements are arranged in a lattice pattern.   
     
     
         13 . The plasma processing apparatus of  claim 12 ,
 wherein a wavelength span is determined based on the dispersion angle of the light dispersion element and distances between the light dispersion element and the light receiving elements so that the measurement light is dispersed for each wavelength or each frequency and an intensity is acquired for each wavelength or each frequency.   
     
     
         14 . The plasma processing apparatus of  claim 10 ,
 wherein the analyzer includes an optical-path length calculation unit, a driving amount determination unit and a driving amount calibration table in which correlation information between an optical-path length of the annular member and the driving amount of the annular member is stored.   
     
     
         15 . The plasma processing apparatus of  claim 14 ,
 wherein the optical-path length calculation unit is configured to calculate an optical-path length between the upper surface of the annular member and the bottom surface of the annular member based on the spectrum of the reflected light; and   the driving amount determination unit is configured to determine the driving amount of the annular member based on the driving amount calibration table.   
     
     
         16 . The plasma processing apparatus of  claim 10 ,
 wherein the analyzer is the same as the controller.   
     
     
         17 . The plasma processing apparatus of  claim 14 ,
 wherein the optical-path length calculation unit includes a Fourier transform unit, a data interpolation unit,   a center calculation unit and an optical-path length determination unit, and   the Fourier transform unit is configured to perform Fourier transform on the spectrum of the reflected light by Fast Fourier Transform (FFT).   
     
     
         18 . The plasma processing apparatus of  claim 17 ,
 wherein the data interpolation unit is configured to interpolate data points within a range including a predetermined peak value of the spectrum of the reflected light after the Fourier transform.   
     
     
         19 . The plasma processing apparatus of  claim 18 ,
 wherein the center calculation unit is configured to calculate a center position of the predetermined peak value of the spectrum of the reflected light after the Fourier transform, and   the optical-path length calculation unit is configured to calculate the optical-path length based on the center position.   
     
     
         20 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a substrate support provided in the plasma processing chamber;   an annular member disposed on the substrate support, and having an upper surface and a bottom surface;   an actuator configured to move the annular member in up and down direction with regard to the substrate support;   an irradiator configured to irradiate measurement light to the annular member;   a detector configured to detect first reflected light from the upper surface and second reflected light from the bottom surface;   an analyzer configured to determine a driving amount of the annular member based on an optical path difference between the first reflected light and the second reflected light; and   a controller configured to control the actuator based on the determined driving amount.