Polishing device and method for adjusting pressure control unit

Abstract

A polishing device is capable of reducing variations in responsiveness of multiple pressure regulators. The polishing device includes multiple buffer tanks T 1 to T 6. Each of the buffer tanks T 1 to T 6 includes a tank section 120 made of a rigid body and a volume adjustment device 122 which adjusts a volume of the buffer tank.

What is claimed is: 
     
         1 . A polishing device, comprising:
 a polishing table, supporting a polishing pad;   a top ring, having a plurality of pressure chambers for pressing a substrate against a polishing surface of the polishing pad;   a plurality of pressure regulators, controlling pressures of gases in the plurality of pressure chambers;   a plurality of pressure sensors, detecting pressures adjusted by the plurality of pressure regulators; and   a plurality of buffer tanks, connected to a plurality of gas transfer lines connecting the plurality of pressure chambers and the plurality of pressure regulators, wherein   each of the plurality of buffer tanks comprises
 a tank section made of a rigid body and 
 a volume adjustment device which adjusts a volume of the buffer tank. 
   
     
     
         2 . The polishing device according to  claim 1 , wherein
 the volume adjustment device comprises
 a closing member which is disposed inside the tank section and closes off a part of an internal space of the tank section, 
 a reciprocating mechanism which reciprocates the closing member, and 
 a positioning member which positions the closing member moved by the reciprocating mechanism. 
   
     
     
         3 . The polishing device according to  claim 1 , further comprising:
 a control device, controlling a pressure of each of the plurality of pressure chambers through each of the plurality of pressure regulators, wherein   the control device
 measures a secondary side pressure of each of the plurality of pressure regulators, and 
 determines a volume of the buffer tank so that a change in the secondary side pressure when a target pressure value of each of the plurality of pressure regulators changes falls within a predetermined allowable range. 
   
     
     
         4 . The polishing device according to  claim 3 , wherein the control device adjusts control parameters input to the plurality of pressure regulators after adjusting the volume. 
     
     
         5 . The polishing device according to  claim 1 , wherein
 when each of the plurality of pressure sensors is defined as a first pressure sensor and each of the plurality of pressure regulators is defined as a first pressure regulator,   the polishing device comprises
 a second pressure sensor prepared in place of the first pressure sensor, and 
 a second pressure regulator prepared in place of the first pressure regulator. 
   
     
     
         6 . The polishing device according to  claim 5 , further comprising:
 a control device, controlling a pressure of each of the plurality of pressure chambers through each of the plurality of pressure regulators, wherein   the control device
 inputs predetermined control parameters into the second pressure regulator, 
 measures a secondary side pressure of the second pressure regulator based on the second pressure sensor, and 
 determines a volume of the buffer tank so that a change in the secondary side pressure when a target pressure value of the second pressure regulator changes falls within a predetermined allowable range. 
   
     
     
         7 . A method for adjusting a pressure control unit, comprising:
 supplying gases to a plurality of pressure chambers built into a top ring for polishing a substrate;   comprising, by the pressure control unit,
 a plurality of pressure regulators, controlling pressures of gases in the plurality of pressure chambers, 
 a plurality of pressure sensors, detecting pressures adjusted by the plurality of pressure regulators, and 
 a plurality of buffer tanks, connected to a plurality of gas transfer lines connecting the plurality of pressure chambers and the plurality of pressure regulators; and 
   determining a volume of each of the plurality of buffer tanks that is variable based on a pressure value measured by each of the pressure sensors corresponding to the volume.   
     
     
         8 . The method for adjusting the pressure control unit according to  claim 7 , further comprising: determining the volume so that a change in a secondary side pressure of each of the plurality of pressure regulators when a target pressure value of each of the plurality of pressure regulators changes falls within a predetermined allowable range. 
     
     
         9 . The method for adjusting the pressure control unit according to  claim 8 , further comprising: adjusting control parameters of the pressure regulator after adjusting the volume. 
     
     
         10 . The method for adjusting the pressure control unit according to  claim 9 , further comprising:
 when each of the plurality of pressure sensors is defined as a first pressure sensor and each of the plurality of pressure regulators is defined as a first pressure regulator,   controlling a pressure in the plurality of pressure chambers by using a second pressure regulator in place of the first pressure regulator; and   measuring the pressure by installing a second pressure sensor in place of the first pressure sensor.