Plasma processing apparatus

Abstract

A plasma processing apparatus is provided with a replacement time detecting unit, which detects the status of residual charges which attract a semiconductor wafer and detects a time when an electrostatic chuck is to be replaced, at a time when a direct voltage application from a direct current source is stopped and the semiconductor wafer is brought up from the electrostatic chuck.

What is claimed is: 
     
         1 . A plasma processing apparatus comprising:
 a processing chamber configured to accommodate a target substrate therein for performing a plasma process on the target substrate by generating a plasma therein;   a mounting table, disposed in the processing chamber, configured to mount the target substrate thereon;   an electrostatic chuck, disposed on the mounting table and having an electrode embedded in an insulating layer, configured to attract and to hold the target substrate thereon electrostatically by a DC voltage applied to the electrode from a DC power supply;   a substrate supporting mechanism configured to be protrusible from the inside of the mounting table and to support the target substrate above the mounting table; and   a charge removing process control unit configured to change a charge removing process of the electrostatic chuck by detecting a state of residual charges of the electrostatic chuck when the target substrate is lifted up from the electrostatic chuck by the substrate supporting mechanism after the application of the DC voltage from the DC power supply is stopped.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein the charge removing process control unit is configured to detect the state of the residual charges of the electrostatic chuck based on a torque or a rotational speed of a driving motor which operates to protrude the substrate supporting mechanism from the mounting table. 
     
     
         3 . The plasma processing apparatus of  claim 2 , wherein the charge removing process control unit is configured to compare an attraction force by the residual charges for attracting the target substrate with a preset value, and to change a normal process of lifting up the target substrate by the substrate supporting mechanism into an emergency process if the attraction force is equal to or greater than the preset value. 
     
     
         4 . The plasma processing apparatus of  claim 1 , wherein the charge removing process control unit is configured to increase an internal pressure of the processing chamber, keeping up with an increase of the residual charges of the electrostatic chuck. 
     
     
         5 . The plasma processing apparatus of  claim 2 , wherein the charge removing process control unit is configured to increase an internal pressure of the processing chamber, keeping up with an increase of the residual charges of the electrostatic chuck. 
     
     
         6 . A plasma processing method comprising:
 loading a target substrate into a processing chamber and placing the target substrate on lift pins which are protrusible from an inside of a mounting table;   mounting the target substrate on an electrostatic chuck of the mounting table by lowering the lift pins;   attracting the target substrate to the electrostatic chuck by applying a DC voltage to the electrostatic chuck;   performing a plasma processing on the target substrate in the processing chamber;   detecting a state of residual charges of the electrostatic chuck when the target substrate on which the plasma processing has been performed is lifted up from the electrostatic chuck by the lift pins after the application of the DC voltage; and   changing a charge removing process of the electrostatic chuck based on the detected state of the residual charges.   
     
     
         7 . The plasma processing method of  claim 6 , wherein the detecting the state of the residual charges of the electrostatic chuck detects the state of the residual charges of the electrostatic chuck based on a torque or a rotational speed of a driving motor which operates to protrude the lift pins from the mounting table. 
     
     
         8 . The plasma processing method of  claim 7 , wherein the changing a charge removing process of the electrostatic chuck includes:
 comparing an attraction force by the residual charges for attracting the target substrate with a preset value; and   changing a normal process of lifting up the target substrate by the substrate supporting mechanism into an emergency process if the attraction force is equal to or greater than the preset value.   
     
     
         9 . The plasma processing method of  claim 6 , wherein the changing the charge removing process of the electrostatic chuck includes increasing an internal pressure of the processing chamber, keeping up with an increase of the residual charges of the electrostatic chuck. 
     
     
         10 . The plasma processing method of  claim 7 , wherein the changing the charge removing process of the electrostatic chuck includes increasing an internal pressure of the processing chamber, keeping up with an increase of the residual charges of the electrostatic chuck.