Plasma processing apparatus and method for controlling the same

Abstract

The invention provides a plasma processing apparatus that realizes a most suitable inner environment of a vacuum vessel for each process. A plasma processing apparatus comprises a vacuum vessel 1 , a first RF power supply 4 , a second RF power supply 21 , a third RF power supply 25 , a first electrode 2 disposed within the vacuum vessel to which is supplied a mixture of a first RF voltage from the first RF power supply and a third RF voltage from the third RF power supply, a second electrode 14 disposed within the vacuum vessel to which is supplied a second RF voltage from the second RF power supply and having an upper surface mounting a sample 12 , and a phase control unit 26 for controlling the phase difference of the second and third RF voltages, wherein the second and third RF voltages are of equal frequency, and the apparatus further comprises a first phase detecting means 32 for detecting the phase of the third RF voltage of the first electrode and a second phase detecting means 31 for detecting the phase of the second RF voltage of the second electrode, and based on the output of the first and second phase detecting means, controls the phase difference of the second and third RF voltages.

1 . A plasma processing apparatus comprising: 
 a vacuum vessel in which plasma is generated;    a first RF power supply, a second RF power supply and a third RF power supply provided outside the vacuum vessel;    a first electrode disposed either inside or outside the vacuum vessel to which a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and a third RF voltage from the third RF power supply; and    an RF radiation unit other than the second electrode that is capacitively coupled with the plasma generated inside the vacuum vessel, wherein the phase difference between the second RF voltage and the third RF voltage having a same frequency is controlled using a signal source other than a phase signal.    
   
   
       2 . The plasma processing apparatus according to  claim 1 , wherein the RF radiation unit coupling capacitively with the plasma is composed of one of the following: an antenna of a parallel plate electrode, a focus ring, a Faraday shield, or another electrode.  
   
   
       3 . The plasma processing apparatus according to  claim 1 , wherein the signal source other than the phase signal utilizes one of the following: an RF voltage, a plasma emission, or a combination of the RF voltage and the plasma emission.  
   
   
       4 . The plasma processing apparatus according to  claim 1 , wherein the RF radiation unit is composed of one of the following: a combination of an antenna of a parallel plate electrode, a focus ring and another electrode; or a combination of a Faraday shield, a focus ring and another electrode.  
   
   
       5 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed inside the vacuum vessel to which a mixture of a first RF voltage from the first RF power supply and a third RF voltage from the third RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency; and    a first phase detecting means for detecting the phase of the third RF voltage of the first electrode, and a second phase detecting means for detecting the phase of the second RF voltage of the second electrode, wherein based on the output from the first phase detecting means and the second phase detecting means, the phase difference between the second RF voltage and the third RF voltage is controlled.    
   
   
       6 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed inside the vacuum vessel to which a mixture of a first RF voltage from the first RF power supply and a third RF voltage from the third RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency;    a voltage detecting means for detecting a potential of the RF being transmitted through a plasma at an inner wall surface of the vacuum vessel; and    a phase difference computing means for computing the phase difference between the second RF voltage and the third RF voltage based on the detected voltage of the voltage detecting means, wherein the phase difference between the second RF voltage and the third RF voltage is controlled so that the output of the phase difference computing means takes a minimum or a specific value.    
   
   
       7 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed inside the vacuum vessel to which a mixture of a first RF voltage from the first RF power supply and a third RF voltage from the third RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency; and    a plasma emission detecting means for detecting an emission status of plasma within the vacuum vessel, wherein the phase difference between the second RF voltage and the third RF voltage is controlled based on the status of the plasma emission.    
   
   
       8 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed inside the vacuum vessel to which    a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a focus ring disposed on a circumference of the sample mounted on the second electrode and to which a third RF voltage from the third RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency; and    a plasma emission detecting means for detecting an emission status of plasma within the vacuum vessel, wherein the phase difference between the second RF voltage and the third RF voltage is controlled based on the status of the plasma emission.    
   
   
       9 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed outside the vacuum vessel to which a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a Faraday shield disposed between the first electrode and the inner side of the vacuum vessel, and to which a third RF voltage from the third RF power supply is supplied;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency; and    a plasma emission detecting means for detecting an emission status of plasma within the vacuum vessel, wherein the phase difference between the second RF voltage and the third RF voltage is controlled based on the status of the plasma emission.    
   
   
       10 . A plasma processing apparatus comprising: 
 a vacuum vessel;    a first RF power supply;    a second RF power supply;    a third RF power supply;    a first electrode disposed outside the vacuum vessel to which a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied;    a Faraday shield disposed between the first electrode and the inner side of the vacuum vessel;    a third electrode disposed inside the vacuum vessel, to which a third RF voltage from the third RF power supply is supplied, and being capacitively coupled with plasma;    a phase control unit for controlling a phase difference between the second RF voltage and the third RF voltage, the second RF voltage and the third RF voltage having the same frequency; and    a plasma emission detecting means for detecting an emission status of plasma within the vacuum vessel, wherein the phase difference between the second RF voltage and the third RF voltage is controlled based on the status of the plasma emission.    
   
   
       11 . A method for controlling a plasma processing apparatus that comprises: 
 a vacuum vessel in which plasma is generated;    a first RF power supply, a second RF power supply and a third RF power supply provided outside the vacuum vessel;    a first electrode disposed either inside or outside the vacuum vessel to which a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied; and    a phase control unit for controlling a phase difference between the second RF voltage and a third RF voltage from the third RF power supply;    wherein the controlling method comprises the steps of:    supplying a predetermined power from the first RF power supply to ignite plasma;    after confirming ignition of plasma, supplying a predetermined power respectively from the second RF power supply and the third RF power supply; and    when starting power supply from the second RF power supply and the third RF power supply, fixing the phase to a predetermined phase angle using a preset mode without carrying out phase control, and after a matching operation has stabilized, starting the phase control.    
   
   
       12 . A method for controlling a plasma processing apparatus that comprises: 
 a vacuum vessel in which plasma is generated;    a first RF power supply, a second RF power supply and a third RF power supply provided outside the vacuum vessel;    a first electrode disposed either inside or outside the vacuum vessel to which a first RF voltage from the first RF power supply is supplied;    a second electrode disposed inside the vacuum vessel, having an upper surface on which a sample is mounted, and to which a second RF voltage from the second RF power supply is supplied; and    a phase control unit for controlling a phase difference between the second RF voltage and a third RF voltage from the third RF power supply;    wherein the controlling method comprises the steps of:    controlling the phase difference between the RF voltage of the second electrode and the third RF voltage having a same frequency using a signal source other than a phase signal, disposed between the second electrode and an RF radiation unit that is capacitively coupled with plasma; and    when removing a deposition film inside the vacuum vessel, controlling the phase difference according to an amount of the deposition film.