Plasma Processing Apparatus and Plasma Processing Method

Abstract

A plasma processing apparatus for subjecting a substrate to be processed to plasma processing includes a processing chamber, a substrate electrode having an electrostatic chuck mechanism, a plasma generator, a high-frequency bias power supply which applies a high-frequency bias voltage to the substrate electrode, a voltage monitor which monitors the high-frequency bias voltage, a current monitor which monitors a high-frequency bias current, a measurement storage unit which stores a resistance component, an induction component and a capacity component of the electrostatic chuck mechanism, which have been calculated beforehand as fitting parameters of an expression V w = V esc - R esc  I esc - L esc   I esc  t - 1 C esc  ∫ I esc   t + A , ( A ) that is an approximate curve of a correlation among a voltage of the substrate, a computing unit which estimates the voltage of the substrate according to the expression, and a control unit that generates a control signal for the high-frequency bias power supply based on the voltage of the substrate.

1 . A plasma processing apparatus for subjecting a substrate to be processed to plasma processing, comprising:
 a processing chamber which processes the substrate to be processed with plasma;   a substrate electrode having an electrostatic chuck mechanism which electrostatically attracts and supports the substrate to be processed;   a plasma generating means which generates plasma in the processing chamber;   a high-frequency bias power supply which applies a high-frequency bias voltage to the substrate electrode;   a voltage monitor which monitors the high-frequency bias voltage;   a current monitor which monitors a high-frequency bias current that flows in the electrostatic chuck mechanism;   a measurement storage unit which stores a resistance component, an induction component and a capacity component each of the electrostatic chuck mechanism, which have been calculated respectively beforehand as fitting parameters of an expression (A) that is an approximate curve of a correlation among a voltage of a substrate to be processed for measurement, the high-frequency bias voltage and the high-frequency bias current which are measured respectively when the substrate to be processed for measurement is mounted on the substrate electrode,   
       
         
           
             
               
                 
                   
                     
                       
                         V 
                         w 
                       
                       = 
                       
                         
                           V 
                           esc 
                         
                         - 
                         
                           
                             R 
                             esc 
                           
                            
                           
                             I 
                             esc 
                           
                         
                         - 
                         
                           
                             L 
                             esc 
                           
                            
                           
                             
                                
                               
                                 I 
                                 esc 
                               
                             
                             
                                
                               t 
                             
                           
                         
                         - 
                         
                           
                             1 
                             
                               C 
                               esc 
                             
                           
                            
                           
                             ∫ 
                             
                               
                                 I 
                                 esc 
                               
                                
                               
                                  
                                 t 
                               
                             
                           
                         
                         + 
                         A 
                       
                     
                     , 
                   
                 
                 
                   
                     ( 
                     A 
                     ) 
                   
                 
               
             
           
         
       
       wherein Vw represents a voltage of the substrate to be processed, Vesc represents the high-frequency bias voltage, Iesc represents the high-frequency bias current, Resc represents the resistance component of the electrostatic chuck mechanism, Lesc represents the induction component of the electrostatic chuck mechanism, Cesc represents the capacity component of the electrostatic chuck mechanism, and A represents an integration constant, the high-frequency bias voltage and the high-frequency bias current being measured respectively when the substrate to be processed is processed with plasma;
 a computing unit which estimates the voltage of the substrate to be processed according to the expression (A), by using the high-frequency bias voltage and the high-frequency bias current which have been stored in the measurement storage unit, and the resistance component, the induction component and the capacity component each of the electrostatic chuck mechanism, which have been stored in the measurement storage unit; and 
 a control unit that generates a control signal for the high-frequency bias power supply based on the voltage of the substrate to be processed, which has been estimated by the computing unit, and transmits the control signal to the high-frequency bias power supply. 
 
     
     
         2 . The plasma processing apparatus according to  claim 1 , wherein the Resc and the Lesc are each controlled to be zero. 
     
     
         3 . The plasma processing apparatus according to  claim 2 , wherein the expression (A) is expressed as in expression (B) according to a frequency domain method,
   V w =V esc   −I   esc   /jωC   esc   (B).
   
     
     
         4 . The plasma processing apparatus according to  claim 1 , wherein:
 the control unit controls the high-frequency bias power supply by generating the control signal for the high-frequency bias power supply, and by transmitting the control signal to the high-frequency bias power supply,   in which the control signal for the high-frequency power supply controls a waveform of the high-frequency bias voltage so that a sag of the voltage of the substrate to be processed is planarized, based on the voltage of the substrate to be processed, which has been estimated by the computing unit.   
     
     
         5 . A plasma processing apparatus for subjecting a substrate to be processed to plasma processing, comprising;
 a processing chamber which processes the substrate to be processed with plasma;   a substrate electrode having an electrostatic chuck mechanism which electrostatically attracts and supports the substrate to be processed;   a plasma generating means which generates plasma in the processing chamber;   a high-frequency bias power supply which applies a high-frequency bias voltage to the substrate electrode;   a voltage monitor which monitors the high-frequency bias voltage;   a current monitor which monitors a high-frequency bias current that flows in the electrostatic chuck mechanism;   a measurement storage unit which stores a resistor component Resc of the electrostatic chuck mechanism, an induction component Lesc of the electrostatic chuck mechanism and a capacity component Cesc of the electrostatic chuck mechanism, which have been calculated respectively beforehand by using an impedance analyzer, and the high-frequency bias voltage Vesc and the high-frequency bias current Iesc, which are measured respectively when the substrate to be processed is processed with plasma;   a computing unit which estimates a voltage Vw of the substrate to be processed according to expression (A),   
       
         
           
             
               
                 
                   
                     
                       
                         V 
                         w 
                       
                       = 
                       
                         
                           V 
                           esc 
                         
                         - 
                         
                           
                             R 
                             esc 
                           
                            
                           
                             I 
                             esc 
                           
                         
                         - 
                         
                           
                             L 
                             esc 
                           
                            
                           
                             
                                
                               
                                 I 
                                 esc 
                               
                             
                             
                                
                               t 
                             
                           
                         
                         - 
                         
                           
                             1 
                             
                               C 
                               esc 
                             
                           
                            
                           
                             ∫ 
                             
                               
                                 I 
                                 esc 
                               
                                
                               
                                  
                                 t 
                               
                             
                           
                         
                         + 
                         A 
                       
                     
                     , 
                   
                 
                 
                   
                     ( 
                     A 
                     ) 
                   
                 
               
             
           
         
       
       by using the high-frequency bias voltage Vesc and the high-frequency bias current Iesc, which have been stored in the measurement storage unit, and the resistance component Resc, the induction component Lesc and the capacity component Cesc each of the electrostatic chuck mechanism, which have been stored in the measurement storage unit; and
 a control unit that generates a control signal for the high-frequency bias power supply based on the voltage Vw of the substrate to be processed, which has been estimated by the computing unit, and transmits the control signal to the high-frequency bias power supply. 
 
     
     
         6 . The plasma processing apparatus according to  claim 5 , wherein the Resc and the Lesc are each controlled to be zero. 
     
     
         7 . The plasma processing apparatus according to  claim 6 , wherein expression (A) is expressed as in expression (B) according to a frequency domain method,
   V w =V esc   −I   esc   /jωC   esc   (B).
   
     
     
         8 . The plasma processing apparatus according to  claim 5 , wherein the control unit controls the high-frequency bias power supply by generating the control signal for the high-frequency bias power supply, and controlling a waveform of the high-frequency bias voltage so that a sag of the voltage Vw of the substrate to be processed is planarized, based on the voltage Vw of the substrate to be processed, which has been estimated by the computing unit, and by transmitting the control signal to the high-frequency bias power supply.