Plasma processing apparatus

Abstract

Provided is a plasma processing apparatus including a processing chamber which is disposed in a vacuum vessel and able to be decompressed, a sample stage on a top surface of which a wafer to be processed is mounted, an opening which is configured to supply a heat-transfer gas to a gap between the wafer and the top surface of the sample stage, a regulator which regulates a flow rate of the heat-transfer gas, and a controller which regulates an operation of the regulator based on a pressure of the gap detected using an amount of the heat-transfer gas leaking from the regulator to the processing chamber through the gap while the wafer is mounted on the sample stage and an amount of the heat-transfer gas supplied from the opening to the processing chamber while the wafer is not mounted on the sample stage.

1 . A plasma processing apparatus comprising:
 a processing chamber which is disposed in a vacuum vessel and able to be decompressed;   a sample stage which is disposed in the processing chamber and on a top surface of which a wafer to be processed is mounted;   an opening which is arranged on the top surface of the sample stage and configured to supply a heat-transfer gas to a gap between the wafer and the top surface of the sample stage while the wafer is mounted on the top surface of the sample stage;   a supply path which is communicated with the opening and through which the heat-transfer gas flows;   a regulator which is disposed on the supply path and regulates a flow rate of the heat-transfer gas; and   a controller which regulates an operation of the regulator based on a pressure of the gap detected using an amount of the heat-transfer gas leaking from the regulator to the processing chamber at an outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage and an amount of the heat-transfer gas supplied from the opening to the processing chamber while the wafer is not mounted on the sample stage,   wherein the plasma processing apparatus processes the wafer using plasma formed in the processing chamber while the heat-transfer gas is supplied to the gap.   
     
     
         2 . The plasma processing apparatus according to  claim 1 , wherein the controller regulates the operation of the regulator based on the pressure of the gap using a result obtained by redetecting, after a predetermined number of wafers are processed, the amount of the heat-transfer gas leaking from the regulator to the processing chamber at the outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage. 
     
     
         3 . The plasma processing apparatus according to  claim 1 , further comprising:
 a dielectric film which forms the top surface of the sample stage and comprises an electrode attracting the wafer mounted on the sample stage by static electricity,   wherein the opening is disposed on a top surface of the dielectric film.   
     
     
         4 . The plasma processing apparatus according to  claim 2 , further comprising:
 a dielectric film which forms the top surface of the sample stage and comprises an electrode attracting the wafer mounted on the sample stage by static electricity,   wherein the opening is disposed on a top surface of the dielectric film.   
     
     
         5 . The plasma processing apparatus according to  claim 1 , wherein the amount of the heat-transfer gas leaking from the regulator to the processing chamber at the outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage is detected using a sum of a volume in the supply path from the regulator to the opening and a volume between the dielectric film and a back surface of the wafer where the wafer is mounted. 
     
     
         6 . The plasma processing apparatus according to  claim 2 , wherein the amount of the heat-transfer gas leaking from the regulator to the processing chamber at the outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage is detected using a sum of a volume in the supply path from the regulator to the opening and a volume between the dielectric film and a back surface of the wafer where the wafer is mounted. 
     
     
         7 . The plasma processing apparatus according to  claim 3 , wherein the amount of the heat-transfer gas leaking from the regulator to the processing chamber at the outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage is detected using a sum of a volume in the supply path from the regulator to the opening and a volume between the dielectric film and a back surface of the wafer where the wafer is mounted. 
     
     
         8 . The plasma processing apparatus according to  claim 4 , wherein the amount of the heat-transfer gas leaking from the regulator to the processing chamber at the outer circumference of the sample stage through the gap while the wafer is mounted on the sample stage is detected using a sum of a volume in the supply path from the regulator to the opening and a volume between the dielectric film and a back surface of the wafer where the wafer is mounted. 
     
     
         9 . The plasma processing apparatus according to  claim 1 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         10 . The plasma processing apparatus according to  claim 2 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         11 . The plasma processing apparatus according to  claim 3 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         12 . The plasma processing apparatus according to  claim 4 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         13 . The plasma processing apparatus according to  claim 5 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         14 . The plasma processing apparatus according to  claim 6 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         15 . The plasma processing apparatus according to  claim 7 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins. 
     
     
         16 . The plasma processing apparatus according to  claim 8 , wherein the controller regulates the operation of the regulator based on the pressure of the gap detected using a pressure value in the processing chamber during evacuation of the processing chamber executed before processing of the wafer begins.