Method for Controlling Electrostatic Attractor and Plasma Processing Apparatus

Abstract

A method for controlling an electrostatic attractor, which attracts an electrode to a gas plate provided in an upper portion of a plasma processing apparatus, includes, among a plasma generation period in which plasma is generated by the plasma processing apparatus and an idle period in which no plasma is generated by the plasma processing apparatus, applying voltages having polarities different from each other to first and second electrodes of the electrostatic attractor in at least the idle period.

1 - 23 . (canceled) 
     
     
         24 . A plasma processing apparatus comprising:
 a chamber;   a substrate support configured to support a substrate in the chamber and disposed in a lower portion of the chamber;   an upper electrode disposed an upper portion of the chamber, and includes:
 a gas plate; 
 an electrode in contact with a lower surface of the gas plate; and 
 an electrostatic chuck that is disposed to be opposed to the substrate support, is interposed between the electrode and the gas plate, has a contact surface in contact with the lower surface of the gas plate and an attraction surface attracting an upper surface of the electrode to the gas plate, and includes a first electrode and a second electrode; 
   a first power supply configured to apply a voltage to the first electrode;   a second power supply configured to apply a voltage to the second electrode; and   a controller configured to control the voltages applied by the first power supply and the second power supply,   wherein the controller performs a control to apply voltages having polarities different from each other to the first electrode and the second electrode of the electrostatic chuck during at least an idle period in which no plasma is generated among a plasma generation period in which plasma is generated and the idle period.   
     
     
         25 . The apparatus of  claim 24 , wherein the electrode has gas discharge holes passing through the electrode,
 wherein the gas plate has gas flow passages configured to supply a processing gas to the gas discharge holes, the gas flow passages being formed in the gas plate at locations where the gas flow passages face the gas discharge holes, and   wherein the plasma processing apparatus further comprises a shield configured to shield radicals or gases moving from the gas discharge holes to a space between the electrode and the gas plate.   
     
     
         26 . The apparatus of  claim 25 , wherein the shield has a connector interposed between the electrode and the gas plate and connecting the gas discharge holes and the gas flow passages. 
     
     
         27 . The apparatus of  claim 26 , wherein the lower surface of the gas plate has a first region facing the contact surface of the electrostatic chuck and a second region facing the gas discharge holes, and
 wherein the connector has an upper end connected to the second region in the lower surface of the gas plate and a lower end connected to the upper surface of the electrode, and defines flow passages, via which the gas discharge holes and the gas flow passages communicate with each other, in the connector.   
     
     
         28 . The apparatus of  claim 27 , wherein the connector is integral with one of the gas plate and the electrode. 
     
     
         29 . The apparatus of  claim 27 , wherein the connector has an upper connector integrated with the gas plate, and a lower connector integrated with the electrode and being in contact with the upper connector. 
     
     
         30 . The apparatus of  claim 28 , wherein the gas plate has a passivation layer at a location in contact with the electrode. 
     
     
         31 . The apparatus of  claim 26 , wherein the connector is separate from the electrode and the gas plate. 
     
     
         32 . The apparatus of  claim 26 , wherein the electrostatic chuck has a main body formed of an elastic dielectric and an electrostatic attraction electrode disposed in the main body, and the electrostatic chuck is disposed between the electrode and the gas plate in a state where the main body is compressed, and
 wherein the compressed main body has the same thickness as that of the connector.   
     
     
         33 . The plasma processing apparatus of  claim 25 , wherein the lower surface of the gas plate has a first region facing the contact surface of the electrostatic chuck and a second region facing the gas discharge holes,
 wherein a gap is formed between the second region and the upper surface of the electrode,   wherein the shield has a depressurizing exhaust device, and exhaust flow passages connected to the exhaust device,   wherein the exhaust flow passages are formed in the gas plate and have lower ends located in the second region, and   wherein the exhaust device depressurizes a space in the gap through the exhaust flow passages.   
     
     
         34 . The apparatus of  claim 25 , wherein the lower surface of the gas plate has a first region facing the contact surface of the electrostatic chuck and a second region facing the gas discharge holes,
 wherein a gap is formed between the second region and the upper surface of the electrode,   wherein the shield has a gas source of a shielding gas, and supply flow passages connected to the gas source, and   wherein the supply flow passages are formed in the gas plate, have lower ends located in the second region, and supply the shielding gas from the gas source to a space in the gap.   
     
     
         35 . The apparatus of  claim 34 , wherein the shielding gas has the same components as those of the processing gas. 
     
     
         36 . A plasma processing apparatus, comprising
 a chamber;   a gas plate disposed in the chamber;   an electrode disposed below the gas plate;   a substrate support disposed in a lower portion of the chamber and configured to support a substrate;   an electrostatic chuck that is disposed in an upper portion of the chamber, is opposed to the substrate support, is configured to attract the electrode to the gas plate, and includes a first electrode and a second electrode;   a plasma generator configured to generate a plasma; and   a controller configured to cause:   applying voltages having polarities different from each other to the first electrode and the second electrode of the electrostatic chuck during at least an idle period in which no plasma is generated among a plasma generation period in which plasma is generated and the idle period.   
     
     
         37 . The apparatus of  claim 36 , wherein the plasma generation period and the idle period are alternatingly repeated, and
 wherein the controller is configured to switch polarities of the voltages applied to the first electrode and the second electrode every idle period.   
     
     
         38 . The apparatus of  claim 36 , wherein the controller is configured to apply a negative voltage to the electrode during the plasma generation period. 
     
     
         39 . The apparatus of  claim 36 , wherein the controller is configured to voltages having the same polarity to the first electrode and the second electrode during the plasma generation period. 
     
     
         40 . The apparatus of  claim 36 , wherein the controller is configured to apply a negative voltage to the electrode and apply positive voltages to the first electrode and the second electrode, respectively, during the plasma generation period. 
     
     
         41 . The apparatus of  claim 40 , wherein the controller is configured to apply positive voltages to the first electrode and the second electrode and apply a negative voltage to the electrode such that a difference between the positive voltages applied to the first electrode and the second electrode and the negative voltage applied to the electrode is set to be equal to a magnitude of the voltages applied to the first electrode and the second electrode during the idle period. 
     
     
         42 . The apparatus of  claim 41 , wherein the negative voltage is applied to the electrode using a direct current power supply connected to the electrode. 
     
     
         43 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a substrate support disposed in the plasma processing chamber, the substrate support including a lower electrode;   a showerhead assembly disposed above the substrate support, the showerhead assembly including:
 a conductive member; 
 an upper electrode below the conductive member; and 
 an electrostatic chuck disposed between the upper electrode and the conductive member, the electrostatic chuck including a first electrostatic electrode and a second electrostatic electrode; 
   a first power supply electrically connected to the lower electrode or the upper electrode;   a second power supply electrically connected to the lower electrode;   a first DC power supply configured to apply a first DC voltage to the first electrostatic electrode, the first DC voltage having a first polarity; and   a second DC power supply configured to apply a second DC voltage to the second electrostatic electrode, the second DC voltage having a second polarity different from the first polarity.