Plasma processing apparatus, and method and program for controlling elevation of focus ring

Abstract

A plasma processing apparatus includes a mounting table, an acquisition unit, a calculation unit, and an elevation control unit. The mounting table mounts thereon a target object as a plasma processing target. The elevation mechanism vertically moves a focus ring surrounding the target object. The acquisition unit acquires state information indicating a measured state of the target object. The calculation unit calculates a height of the focus ring at which positional relation between an upper surface of the target object and an upper surface of the focus ring satisfies a predetermined distance based on the state of the target object that is indicated by the state information acquired by the acquisition unit. The elevation control unit controls the elevation mechanism to vertically move the focus ring to the height calculated by the calculation unit.

What is claimed is: 
     
         1 . A plasma processing apparatus comprising:
 a mounting table on which a target object as a plasma processing target is mounted;   an elevation mechanism configured to vertically move a focus ring surrounding the target object;   an acquisition unit configured to acquire state information indicating a measured state of the target object;   a calculation unit configured to calculate a height of the focus ring at which positional relation between an upper surface of the target object and an upper surface of the focus ring satisfies a predetermined distance based on the state of the target object that is indicated by the state information acquired by the acquisition unit; and   an elevation control unit configured to control the elevation mechanism to vertically move the focus ring to the height calculated by the calculation unit.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein the state of the target object includes one or both of a thickness of the target object and an outer diameter of the target object. 
     
     
         3 . The plasma processing apparatus of  claim 1 , further comprising:
 a measuring unit configured to measure a height of the upper surface of the focus ring,   wherein the calculation unit calculates the height of the focus ring at which the positional relation satisfies the predetermined distance based on the state of the target object and the height of the upper surface of the focus ring that is measured by the measuring unit.   
     
     
         4 . The plasma processing apparatus of  claim 2 , further comprising:
 a measuring unit configured to measure a height of the upper surface of the focus ring,   wherein the calculation unit calculates the height of the focus ring at which the positional relation satisfies the predetermined distance based on the state of the target object and the height of the upper surface of the focus ring that is measured by the measuring unit.   
     
     
         5 . The plasma processing apparatus according to  claim 3 , wherein the elevation mechanism is provided at a plurality of positions in a circumferential direction of the focus ring,
 the state information includes state measurement results obtained at a plurality of positions in a circumferential direction of the target object,   the calculation unit calculates a height of the focus ring at which the positional relation between the upper surface of the target object and the upper surface of the focus ring satisfies the predetermined distance for each of the plurality of positions in the circumferential direction of the focus ring based on the state measurement results obtained at the plurality of positions that are indicated by the state information, and   the elevation control unit controls the elevation mechanism to vertically move the focus ring to the calculated height.   
     
     
         6 . The plasma processing apparatus according to  claim 4 , wherein the elevation mechanism is provided at a plurality of positions in a circumferential direction of the focus ring,
 the state information includes state measurement results obtained at a plurality of positions in a circumferential direction of the target object,   the calculation unit calculates a height of the focus ring at which the positional relation between the upper surface of the target object and the upper surface of the focus ring satisfies the predetermined distance for each of the plurality of positions in the circumferential direction of the focus ring based on the state measurement results obtained at the plurality of positions that are indicated by the state information, and   the elevation control unit controls the elevation mechanism to vertically move the focus ring to the calculated height.   
     
     
         7 . An elevation control method comprising:
 acquiring state information of a target object as a plasma processing target;   calculating a height of a focus ring at which positional relation between an upper surface of the target object mounted on a mounting table and an upper surface of the focus ring surrounding the target object satisfies a predetermined distance based on a state of the target object which is indicated by the acquired state information; and   controlling an elevation mechanism configured to vertically move the focus ring to the calculated height,   wherein said acquiring, said calculating and said controlling are executed by a computer.   
     
     
         8 . A program for controlling elevation of a focus ring, which is executed by a computer to perform processes including:
 acquiring state information of a target object as a plasma processing target;   calculating a height of a focus ring at which positional relation between an upper surface of the target object mounted on a mounting table and an upper surface of the focus ring surrounding the target object satisfies a predetermined distance based on a state of the target object which is indicated by the acquired state information; and   controlling an elevation mechanism configured to vertically move the focus ring to the calculated height.