Plasma Processing apparatus and method

Abstract

A plasma processing apparatus for processing a substrate by using a plasma includes a processing chamber for accommodating and processing the substrate therein, a lower electrode for mounting the substrate thereon in the processing chamber, an upper electrode disposed to face the lower electrode in the processing chamber, a radio frequency power supply for supplying a radio frequency power to at least one of the lower and the upper electrode, to thereby generate the plasma between the lower and the upper electrode, and an electrical characteristic control unit for adjusting an impedance of a circuit at the side of an electrode to the plasma for a frequency of at least one radio frequency wave present in the processing chamber such that the circuit does not resonate.

1 . A plasma processing apparatus for processing a substrate by using a plasma, comprising: 
 a processing chamber for accommodating and processing the substrate therein;    a lower electrode for mounting the substrate thereon in the processing chamber;    an upper electrode disposed to face the lower electrode in the processing chamber;    a radio frequency power supply for supplying a radio frequency power to at least one of the lower and the upper electrode, to thereby generate the plasma between the lower and the upper electrode; and    an electrical characteristic control unit for adjusting an impedance of a circuit at the side of an electrode to the plasma for a frequency of at least one radio frequency wave present in the processing chamber such that the circuit does not resonate.    
   
   
       2 . The plasma processing apparatus of  claim 1 , wherein the electrical characteristic control unit adjusts an impedance of a circuit at the side of a facing electrode which faces a power supply electrode to which the radio frequency power is supplied.  
   
   
       3 . The plasma processing apparatus of  claim 1 , wherein the electrical characteristic control unit has a variable element for varying the impedance.  
   
   
       4 . The plasma processing apparatus of  claim 3 , wherein the electrical characteristic control unit has a controller for controlling the impedance by adjusting the variable element.  
   
   
       5 . The plasma processing apparatus of  claim 4 , wherein the electrical characteristic control unit has an impedance detector for detecting the impedance.  
   
   
       6 . The plasma processing apparatus of  claim 5 , wherein the controller controls the impedance by adjusting the variable element based on a detection result from the impedance detector.  
   
   
       7 . The plasma processing apparatus of  claim 1 , wherein the electrical characteristic control unit has an electrical characteristic control mechanism connected to the side of an electrode where the impedance is adjusted, and adjusts a reactance of a circuit at the side of the electrical characteristic control mechanism from an electrode surface facing the plasma to have a negative value.  
   
   
       8 . The plasma processing apparatus of  claim 1 , wherein the electrical characteristic control unit adjusts the impedance to deviate by a magnitude within 10 Ω from a resonance point.  
   
   
       9 . The plasma processing apparatus of  claim 7 , wherein the electrical characteristic control unit adjusts the reactance to have a negative value of −50 Ω or below.  
   
   
       10 . The plasma processing apparatus of  claim 1 , wherein the upper electrode is divided into a plurality of electrode portions, and the electrical characteristic control unit is installed in at least one of the plurality of electrode portions.  
   
   
       11 . The plasma processing apparatus of  claim 1 , further comprising a DC power supply for applying a DC voltage to at least one of the lower and the upper electrode.  
   
   
       12 . The plasma processing apparatus of  claim 11 , wherein the DC voltage is applied to the upper electrode.  
   
   
       13 . A plasma processing apparatus for processing a substrate by using a plasma, comprising: 
 a processing chamber for accommodating and processing the substrate therein;    a lower electrode for mounting the substrate thereon in the processing chamber;    an upper electrode disposed to face the lower electrode in the processing chamber;    a radio frequency power supply for supplying a radio frequency power to at least one of the lower and the upper electrode, to thereby generate the plasma in a processing space between the lower and the upper electrode; and    an electrical characteristic control unit for adjusting an electrical characteristic of a circuit at the side of an electrode to the plasma such that a value of current flowing into the electrode from the processing space does not reach a maximum current value.    
   
   
       14 . The plasma processing apparatus of  claim 13 , wherein the electrical characteristic control unit adjusts an electrical characteristic of a circuit at the side of a facing electrode which faces a power supply electrode to which the radio frequency power is supplied.  
   
   
       15 . The plasma processing apparatus of  claim 13 , wherein the electrical characteristic control unit has a variable element for varying the current value.  
   
   
       16 . The plasma processing apparatus of  claim 15 , wherein the electrical characteristic control unit has a controller for controlling the current value by adjusting the variable element.  
   
   
       17 . The plasma processing apparatus of  claim 16 , wherein the electrical characteristic control unit has a current value detector for detecting the current value.  
   
   
       18 . The plasma processing apparatus of  claim 17 , wherein the controller controls the current value by adjusting the variable element based on a detection result from the current value detector.  
   
   
       19 . The plasma processing apparatus of  claim 13 , wherein the electrical characteristic control unit adjusts the electrical characteristic such that the current value is not smaller than ½ of the maximum current value.  
   
   
       20 . The plasma processing apparatus of  claim 13 , wherein the upper electrode is divided into a plurality of electrode portions, and the electrical characteristic control unit is installed in at least one of the plurality of electrode portions.  
   
   
       21 . The plasma processing apparatus of  claim 13 , further comprising a DC power supply for applying a DC voltage to at least one of the lower and the upper electrode.  
   
   
       22 . The plasma processing apparatus of  claim 21 , wherein the DC voltage is applied to the upper electrode.  
   
   
       23 . A plasma processing method, comprising the steps of: 
 mounting a substrate on a lower electrode disposed to face an upper electrode in a processing chamber;    supplying a radio frequency power to at least one of the lower and the upper electrode to thereby generate a plasma therebetween; and    processing the substrate by using the plasma,    wherein an impedance of a circuit at the side of an electrode to the plasma for a frequency of at least one radio frequency wave present in the processing chamber is adjusted such that the circuit does not resonate.    
   
   
       24 . The plasma processing method of  claim 23 , wherein an impedance of a circuit at the side of a facing electrode which faces a power supply electrode, to which the radio frequency power is supplied, is adjusted such that the circuit does not resonate.  
   
   
       25 . The plasma processing method of  claim 23 , wherein the impedance is adjusted to deviate by a magnitude within 10 Ω from a resonance point.  
   
   
       26 . The plasma processing method of  claim 23 , wherein a DC voltage is applied to at least one of the lower and the upper electrode.  
   
   
       27 . The plasma processing method of  claim 26 , wherein the DC voltage is applied to the upper electrode.  
   
   
       28 . A plasma processing method, comprising the steps of: 
 mounting a substrate on a lower electrode disposed to face an upper electrode in a processing chamber;    supplying a radio frequency power to at least one of the lower and the upper electrode to thereby generate a plasma in a processing space therebetween; and    processing the substrate by using the plasma,    wherein an electrical characteristic of a circuit at the side of an electrode to the plasma is adjusted such that a value of current flowing into the electrode from the processing space does not reach a maximum current value.    
   
   
       29 . The plasma processing method of  claim 28 , wherein an electrical characteristic of a circuit at the side of a facing electrode which faces a power supply electrode, to which the radio frequency power is supplied, is adjusted such that a value of current flowing into the facing electrode does not reach a maximum current value.  
   
   
       30 . The plasma processing method of  claim 28 , wherein the electrical characteristic is adjusted such that the current value is not smaller than ½ of the maximum current value.  
   
   
       31 . The plasma processing method of  claim 28 , wherein a DC voltage is applied to at least one of the lower and the upper electrode.  
   
   
       32 . The plasma processing method of  claim 31 , wherein the DC voltage is applied to the upper electrode.