Plasma processing apparatus

Abstract

A plasma processing apparatus has a liquid storage vessel which is formed outside of a dielectric window and in which a plasma-exciting coil or electrode is placed inside and moreover in which an electrically insulative liquid is stored in the inside of the liquid storage vessel, as well as a cooling unit and a heating unit for the liquid. Temperature of the liquid stored in the liquid storage portion is adjusted, by which temperature of the plasma-exciting coil or electrode and the dielectric window is controlled via the liquid.

1 . A plasma processing apparatus for imparting an electromagnetic field to reactant gas introduced into a evacuated processing chamber to excite plasma and performing plasma processing on a substrate set in the processing chamber, comprising: 
 a vacuum vessel which defines the processing chamber in which the substrate is held and the plasma processing for the substrate is performed, and which includes a dielectric window forms a part of the vacuum vessel, for hermetically closing the vacuum chamber, and a gas supply portion for supplying the reactant gas into the processing chamber;    a plasma-exciting coil which is placed so as to confront the processing chamber via the dielectric window, for imparting an electromagnetic field to interior of the processing chamber via the dielectric window with RF power applied;    an evacuation unit for evacuating the interior of the processing chamber to draw a vacuum so that pressure in the processing chamber is kept generally constant;    an RF power supply for applying the RF power to the plasma-exciting coil; and    a liquid storage vessel which includes the dielectric window as a part thereof and which defines in interior thereof a liquid chamber for storing therein an electrically insulative liquid so that an opposite surface to a processing chamber-side surface of the dielectric window is immersed in the liquid and in which the plasma-exciting coil is placed.    
   
   
       2 . The plasma processing apparatus as claimed in  claim 1 , further comprising a liquid temperature adjusting unit which has a cooling unit and/or a heating unit for the electrically insulative liquid and for adjusting temperature of the liquid stored in the liquid storage vessel to control temperature of the plasma-exciting coil and the dielectric window via the liquid.  
   
   
       3 . The plasma processing apparatus as claimed in  claim 2 , wherein the liquid storage vessel except for the dielectric window is formed of an electrical conductor.  
   
   
       4 . The plasma processing apparatus as claimed in  claim 2 , wherein 
 the liquid storage vessel is integrated with the dielectric window whereby an integrated dielectric window is formed, and the integrated dielectric window has a liquid flow passage for the electrically insulative liquid inside thereof as the liquid chamber in which the plasma-exciting coil is placed.    
   
   
       5 . The plasma processing apparatus as claimed in  claim 2 , wherein the liquid temperature adjusting unit is placed outside the liquid storage vessel, the plasma processing apparatus further comprising: 
 a liquid circulating unit for circulating the electrically insulative liquid into the liquid chamber through a liquid flow passage communicated with the liquid chamber so that the liquid is circulatable therealong.    
   
   
       6 . The plasma processing apparatus as claimed in  claim 2 , wherein the liquid temperature adjusting unit has a heat exchange portion which is provided on a wall portion of the liquid storage vessel and which serves for heat exchange with the electrically insulative liquid stored in the liquid storage vessel, and 
 a fluid stored in the heat exchange portion so as to be separable from the electrically insulative liquid is temperature-controlled by the cooling unit or the heating unit, whereby temperature of the electrically insulative liquid in the liquid storage portion is adjusted.    
   
   
       7 . The plasma processing apparatus as claimed in  claim 2 , wherein the cooling unit is an air cooling unit for air cooling an outer wall surface of the liquid storage vessel, and 
 the heating unit is a heater placed inside or outside the liquid storage vessel.    
   
   
       8 . The plasma processing apparatus as claimed in  claim 2 , wherein the liquid temperature adjusting unit comprises: 
 a supply portion of the electrically insulative liquid to the liquid chamber; and    a discharge portion for discharge of liquid vapor generated by vaporization of the electrically insulative liquid from the liquid chamber, and wherein    the electrically insulative liquid is a liquid which has a boiling point at or near an adjustment temperature of the dielectric window and the plasma-exciting coil or a temperature therearound.    
   
   
       9 . The plasma processing apparatus as claimed in  claim 1 , wherein in the liquid storage vessel, the electrically insulative liquid is stored so that the plasma-exciting coil is further immersed in the electrically insulative liquid.  
   
   
       10 . The plasma processing apparatus as claimed in  claim 1 , wherein the plasma-exciting coil is brought into close contact with the liquid chamber-side surface of the dielectric window with a pressure of the electrically insulative liquid supplied into the liquid storage vessel.  
   
   
       11 . The plasma processing apparatus as claimed in  claim 10 , further comprising: 
 a liquid chamber dividing member for dividing the liquid storage vessel into a first chamber to which the electrically insulative liquid is supplied, and a second chamber which is communicated with the first chamber so that the liquid supplied to the first chamber can be supplied to inside of the second chamber and in which the liquid chamber-side surface of the dielectric window and the plasma-exciting coil are placed inside; and    a support guide member for, in the liquid chamber, supporting the liquid chamber dividing member while guiding a dividing position between the first chamber and the second chamber along a variable direction, wherein    the plasma-exciting coil is pressed against and brought into close contact with the surface of the dielectric window by a pressure difference between the liquid stored in the first chamber and the liquid stored in the second chamber.    
   
   
       12 . The plasma processing apparatus as claimed in  claim 11 , wherein in the second chamber of the liquid storage vessel is formed a generally spiral-shaped liquid flow passage in which gaps of the generally spirally turned plasma-exciting coil are surrounded by the liquid chamber dividing member and the dielectric window.  
   
   
       13 . The plasma processing apparatus as claimed in  claim 12 , wherein a supply position of the electrically insulative liquid from the first chamber to the second chamber is set on a center side of the liquid flow passage so that the liquid is circulatable from center side toward outer peripheral side of the generally spiral-shaped liquid flow passage formed between the spiral-shaped plasma-exciting coil in the second chamber of the liquid storage vessel.  
   
   
       14 . The plasma processing apparatus as claimed in  claim 2 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       15 . The plasma processing apparatus as claimed in  claim 2 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       16 . The plasma processing apparatus as claimed in  claim 3 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       17 . The plasma processing apparatus as claimed in  claim 4 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       18 . The plasma processing apparatus as claimed in  claim 5 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       19 . The plasma processing apparatus as claimed in  claim 6 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       20 . The plasma processing apparatus as claimed in  claim 7 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       21 . The plasma processing apparatus as claimed in  claim 8 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       22 . The plasma processing apparatus as claimed in  claim 9 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       23 . The plasma processing apparatus as claimed in  claim 10 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       24 . The plasma processing apparatus as claimed in  claim 11 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       25 . The plasma processing apparatus as claimed in  claim 12 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       26 . The plasma processing apparatus as claimed in  claim 13 , wherein the electrically insulative liquid is pure water having a resistivity of 1×10 5  Ω·cm or more.  
   
   
       27 . The plasma processing apparatus as claimed in  claim 3 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       28 . The plasma processing apparatus as claimed in  claim 4 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       29 . The plasma processing apparatus as claimed in  claim 5 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       30 . The plasma processing apparatus as claimed in  claim 6 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       31 . The plasma processing apparatus as claimed in  claim 7 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       32 . The plasma processing apparatus as claimed in  claim 8 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       33 . The plasma processing apparatus as claimed in  claim 9 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       34 . The plasma processing apparatus as claimed in  claim 10 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       35 . The plasma processing apparatus as claimed in  claim 11 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       36 . The plasma processing apparatus as claimed in  claim 12 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.  
   
   
       37 . The plasma processing apparatus as claimed in  claim 13 , wherein the electrically insulative liquid is a fluorine inert oil, a silicone oil, or organic oils and fats.