Plasma processing apparatus and method and apparatus for measuring DC potential

Abstract

In a plasma processing apparatus, a member for propagating high frequency from a high frequency power supply and/or to which the high frequency is applied. A power feed rod is electromagnetically shielded between a matching unit and a bottom plate of a chamber by a coaxial cylindrical conductor connected to a ground potential. A surface potential system disposed in an appropriate distance from the power feed rod in radius direction is installed in the cylindrical conductor, and measures in a non-contact state the electrostatic surface potential of the power feed rod through electrostatic capacitance and provides a controller with a surface potential detection signal including surface potential measurement value information. The controller performs a required signal processing or operation processing on the basis of the surface potential detection signal from the surface potential system, thereby obtaining the measurement value of the DC potential on the power feed rod.

1 . A DC voltage measuring method, for use with a plasma processing apparatus in which a high frequency voltage from a high frequency power supply is applied to a high frequency electrode provided in a processing vessel through a high frequency feeding conductor, for measuring a DC potential of the high frequency electrode or the high frequency feeding conductor, 
 wherein a measurement value of the DC potential is obtained by non-contactly measuring an electrostatic surface potential of the high frequency electrode or the high frequency feeding conductor by using electrostatic capacitance.    
   
   
       2 . A DC voltage measuring apparatus, for use with a plasma processing apparatus in which a high frequency voltage from a high frequency power supply is applied to a high frequency electrode provided in a processing vessel through a high frequency feeding conductor, for measuring a DC potential of the high frequency electrode or the high frequency feeding conductor, the DC voltage measuring apparatus comprising: 
 a unit for obtaining a measurement value of the DC potential by non-contactly measuring an electrostatic surface potential of the high frequency electrode or the high frequency feeding conductor by using electrostatic capacitance.    
   
   
       3 . A plasma processing apparatus comprising: 
 a processing vessel for providing a depressurized space for performing a plasma processing on a substrate to be processed;    a first electrode disposed in the processing vessel;    a processing gas supply unit for supplying a processing gas into the processing vessel;    a high frequency power supply for generating a high frequency voltage for forming a plasma;    a high frequency feeding conductor connected to the first electrode for supplying the high frequency voltage from the high frequency power supply to the first electrode; and    a DC potential measurement unit for non-contactly measuring an electrostatic surface potential of the first electrode or the high frequency feeding conductor by using electrostatic capacitance to obtain the DC potential.    
   
   
       4 . The plasma processing apparatus of  claim 3 , comprising a second electrode disposed to face the first electrode in parallel in the processing vessel.  
   
   
       5 . The plasma processing apparatus of  claim 4 , wherein the substrate to be processed is disposed on the first electrode, and vent-holes for discharging the processing gas toward the first electrode are provided in the second electrode.  
   
   
       6 . The plasma processing apparatus of  claim 3 , comprising: 
 a matching unit for performing an impedance matching between the high frequency power supply side and a load side, the matching unit having an input terminal electrically coupled to the high frequency power supply and an output terminal electrically coupled to the high frequency feeding conductor.    
   
   
       7 . The plasma processing apparatus of  claim 6 , wherein the matching unit is installed outside the processing vessel, and the high frequency feeding conductor between the matching unit and the processing vessel is surrounded with a cylindrical conductor connected to a ground potential.  
   
   
       8 . The plasma processing apparatus of  claim 7 , wherein the cylindrical conductor includes a first cylindrical conductor portion whose one end is coupled to the processing vessel; a second cylindrical conductor portion whose one end is coupled to the matching unit; and a first connecting part for attachably and detachably connecting the other ends of the first and the second cylindrical conductor portion with each other; and wherein a probe of the DC potential measurement unit is installed in the first connecting part.  
   
   
       9 . The plasma processing apparatus of  claim 8 , wherein the high frequency feeding conductor includes a first bar-type conductor whose one end is fixed to a rear surface of the first electrode; a second bar-type conductor whose one end is fixed to the output terminal of the matching unit; and a second connecting part for attachably and detachably connecting the other ends of the first and the second bar-type conductor with each other; and wherein the second connecting part is disposed in a position corresponding to the first connecting part.  
   
   
       10 . An electrical joint member provided between conductive members joined with each other in a processing apparatus in order to reduce an electrical resistance between the conductive members, comprising: 
 an elastic body; and    a surface metal layer of aluminum formed on a surface of the elastic body.    
   
   
       11 . The electrical joint member of  claim 10 , wherein the elastic body is formed of an organic compound material.  
   
   
       12 . The electrical joint member of  claim 10 , wherein the surface metal layer is formed on the surface of the elastic body by evaporation or CVD.  
   
   
       13 . The electrical joint member of  claim 10 , wherein a thickness of the surface metal layer is equal to or less than 100 μm.  
   
   
       14 . The electrical joint member of  claim 10 , wherein a high frequency flows between the conductive members joined with each other.  
   
   
       15 . A plasma processing apparatus constituted by assembling a plurality of conductive members and performing a predetermined processing on a substrate to be processed by a plasma of a processing gas, the processing gas being converted into the plasma by using a high frequency, wherein the electrical joint member described in  claim 10  is provided between the conductive members joined with each other.  
   
   
       16 . The electrical joint member of  claim 10 , wherein the elastic body is a spiral made of a metal material.  
   
   
       17 . The electrical joint member of  claim 16 , wherein the metal material constituting the elastic body is titanium, a stainless steel or a copper alloy.  
   
   
       18 . An electrical joint member provided between conductive members joined with each other in a processing apparatus in order to reduce an electrical resistance between the conductive members, comprising: 
 an elastic body made of a first metal material; and    a surface metal layer made of a second metal material and formed on a surface of the elastic body, the second metal material having a resistivity smaller than that of the first metal material and causing no negative effects on a process.    
   
   
       19 . The electrical, joint member of  claim 18 , wherein the elastic body is a spiral.  
   
   
       20 . The electrical joint member of  claim 18 , wherein the first metal material is titanium, a stainless steel or a copper alloy.  
   
   
       21 . The electrical joint member of  claim 18 , wherein the second metal material is aluminum.  
   
   
       22 . The electrical joint member of  claim 18 , wherein the surface metal layer is formed on the surface of the elastic body by evaporation or CVD.  
   
   
       23 . The electrical joint member of  claim 18 , wherein a thickness of the surface metal layer is equal to or less than 100 μm.  
   
   
       24 . The electrical joint member of  claim 18 , wherein a high frequency flows between the conductive members joined with each other.  
   
   
       25 . A plasma processing apparatus constituted by assembling a plurality of conductive members and performing a predetermined processing on a substrate to be processed by a plasma of a processing gas, the processing gas being converted into the plasma by using a high frequency, wherein the electrical joint member described in  claim 18  is provided between the conductive members joined with each other.