Plasma processing apparatus and plasma processing method

Abstract

The present invention provides a plasma processing apparatus having a radio frequency power supply supplying time-modulated radio frequency power which is controllable widely with high precision, and a plasma processing method using the plasma processing apparatus. The plasma processing apparatus includes: a vacuum chamber; a first radio frequency power supply for generating plasma in the vacuum chamber; a sample holder disposed in the vacuum chamber, on which a sample is placed; and a second radio frequency power supply supplying radio frequency power to the sample holder, wherein at least one of the first radio frequency power supply and the second radio frequency power supply supplies time-modulated radio frequency power, one of parameters of controlling the time-modulation has two or more different control ranges, and one of the control ranges is a control range for a high-precision control.

What is claimed is: 
     
         1 . A plasma processing apparatus, comprising:
 a vacuum chamber;   a first radio frequency power supply for generating plasma in the vacuum chamber;   a sample holder disposed in the vacuum chamber, on which a sample is placed; and   a second radio frequency power supply supplying radio frequency power to the sample holder,   wherein at least one of the first radio frequency power supply and the second radio frequency power supply supplies time-modulated radio frequency power, one of parameters of controlling the time-modulation has two or more different control ranges, and one of the control ranges is a control range for a high-precision control.   
     
     
         2 . The plasma processing apparatus according to  claim 1 , wherein the parameter is at least one of a duty ratio, a repetition frequency, an on-time, and an off-time. 
     
     
         3 . The plasma processing apparatus according to  claim 2 , wherein:
 at least one of the first radio frequency power supply and the second radio frequency power supply includes an A/D converter and a pulse generator,   the A/D converter receives the two or more different control ranges at different timings, and   the pulse generator generates a pulse controlled in a control range selected by a control range switching signal from each of the two different control ranges received by the A/D converter.   
     
     
         4 . The plasma processing apparatus according to  claim 3 , wherein at least one of the first radio frequency power supply and the second radio frequency power supply is the second radio frequency power supply. 
     
     
         5 . The plasma processing apparatus according to  claim 2 , wherein at least one of the first radio frequency power supply and the second radio frequency power supply includes radio frequency power supplies of the same number as the number of the two or more different control ranges. 
     
     
         6 . A plasma processing method using a plasma processing apparatus including a vacuum chamber, a first radio frequency power supply for generating plasma in the vacuum chamber, a sample holder disposed in the vacuum chamber, on which a sample is placed, and a second radio frequency power supply supplying radio frequency power to the sample holder, wherein
 at least one of the first radio frequency power supply and the second radio frequency power supply supplies time-modulated radio frequency power, the time-modulation is controlled by a parameter having two or more different control ranges, and one of the control ranges is a control range for a high-precision control.   
     
     
         7 . The plasma processing method according to  claim 6 , wherein a period when the time-modulated radio frequency power is not applied is in the range of 10 to 1000 ms. 
     
     
         8 . The plasma processing method according to  claim 6 , wherein the period when the time-modulated radio frequency power is not applied is equal to or more than a residence time of a reaction product. 
     
     
         9 . A plasma processing method in which a sample having a Poly-Si film, a SiO 2  film, an amorphous carbon film, a SiN film, and a BARC film is plasma-etched while time-modulated radio frequency power is supplied to the sample, wherein:
 a repetition frequency has a first control range requiring a high-precision control and a second control range not requiring the high-precision control,   a duty ratio has a third control range requiring the high-precision control and a fourth control range not requiring the high-precision control,   the SiN film is etched in the first control range and the fourth control range,   the amorphous carbon film is etched in the second control range and the fourth control range,   the SiO 2  film is etched in the first control range and the third control range, and   a part of the Poly-Si film is etched in the first control range and the third control range.