Attracting method, mounting table, and plasma processing apparatus

Abstract

A method of attracting an object to a mounting table is provided. The object is a substrate, an edge ring, or a combination of the substrate and the edge ring. The mounting table is provided with an electrostatic chuck including electrodes. After the object is placed on the electrostatic chuck, n-phase alternating current (AC) voltages (n≥2) are applied to the electrodes. Each phase voltage of the n-phase AC voltages has a phase different from each other, and the phase voltage of the n-phase AC voltages is applied based on a self-bias voltage of the object.

What is claimed is: 
     
         1 . A method of attracting an object to a mounting table provided with an electrostatic chuck including electrodes, the method comprising:
 placing the object on the electrostatic chuck; and   applying n-phase alternating current (AC) voltages (n≥2) to the electrodes, each phase voltage of the n-phase AC voltages having a phase different from each other; wherein
 the object is a substrate, an edge ring, or a combination of the substrate and the edge ring, and 
 the phase voltage of the n-phase AC voltages is applied based on a self-bias voltage of the object. 
   
     
     
         2 . The method according to  claim 1 , wherein the phase voltage of the n-phase AC voltages is obtained by superimposing, on an AC component, negative direct-current (DC) voltage based on the self-bias voltage of the object. 
     
     
         3 . The method according to  claim 2 , wherein the self-bias voltage is calculated in accordance with a condition of plasma processing. 
     
     
         4 . The method according to  claim 2 , wherein the self-bias voltage is detected by a voltage detector configured to detect voltage of the object. 
     
     
         5 . A mounting table comprising:
 a base;   an electrostatic chuck provided on the base;   n number of electrodes (n≥2) provided inside the electrostatic chuck; and   a power supply configured to apply n-phase alternating current (AC) voltages to the electrodes, each phase voltage of the n-phase AC voltages having a phase different from each other; wherein   the phase voltage of the n-phase AC voltages is applied based on a self-bias voltage of an object that is placed on the electrostatic chuck.   
     
     
         6 . The mounting table according to  claim 5 , wherein the phase voltage of the n-phase AC voltages is obtained by superimposing, on an AC component, negative direct-current (DC) voltage based on the self-bias voltage of the object. 
     
     
         7 . A plasma processing apparatus comprising the mounting table according to  claim 5 . 
     
     
         8 . The plasma processing apparatus according to  claim 7 , further comprising a gas supply part configured to supply a heat transfer gas to a space between an upper surface of the mounting table and a back surface of the object; wherein
 the object is a substrate, an edge ring, or a combination of the substrate and the edge ring.