Plasma processing apparatus and method

Abstract

A plasma processing apparatus includes a process container that forms a process space to accommodate a target substrate, and a first electrode and a second electrode disposed opposite each other inside the process container. The first electrode is an upper electrode and the second electrode is a lower electrode and configured to support the target substrate through a mount face. A correction ring is disposed to surround the target substrate placed on the mount face of the second electrode. The correction ring includes a combination of a first ring to be around the target substrate and a second ring arranged around or above the first ring. A power supply unit is configured to apply a first electric potential and a second electric potential respectively to the first ring and the second ring to generate a potential difference between the first and second rings. The power supply unit is configured to variably set the potential difference.

1 . (canceled) 
     
     
         2 . A plasma processing apparatus comprising:
 a process container that forms a process space to accommodate a target substrate;   a vacuum pump connected to an exhaust port of the process container to vacuum-exhaust gas from inside the process container;   a first electrode and a second electrode disposed opposite each other inside the process container, the first electrode being an upper electrode and the second electrode being a lower electrode and configured to support the target substrate through a mount face;   a first radio frequency (RF) power supply configured to apply a first RF power to the first electrode or the second electrode;   a second RF power supply configured to apply a second RF power to the second electrode, the second RF power having a frequency lower than that of the first RF power;   a process gas supply source configured to supply a process gas into the process container;   a correction ring disposed around the second electrode inside the process container to surround the target substrate placed on the mount face of the second electrode, the correction ring including a combination of a first ring to be around the target substrate and a second ring arranged around or above the first ring; and   a power supply unit configured to apply a first electric potential and a second electric potential respectively to the first ring and the second ring respectively through a first feed line and a second feed line to generate a potential difference between the first and second rings, the power supply unit being configured to variably set the potential difference.   
     
     
         3 . The plasma processing apparatus according to  claim 2 , wherein the first ring and the second ring are disposed on an inner side and an outer side, respectively. 
     
     
         4 . The plasma processing apparatus according to  claim 2 , wherein the second ring includes a portion disposed above the first ring. 
     
     
         5 . The plasma processing apparatus according to  claim 2 , wherein each of the first and second feed lines is provided with a low-pass filter. 
     
     
         6 . The plasma processing apparatus according to  claim 2 , wherein the first ring is provided with a cooling system configured to cool the first ring. 
     
     
         7 . The plasma processing apparatus according to  claim 6 , wherein the cooling system includes a temperature measuring member configured to measure a temperature of the first ring, and a temperature controller configured to control the temperature of the first ring on a basis of a signal from the temperature measuring member. 
     
     
         8 . The plasma processing apparatus according to  claim 2 , wherein the power supply unit includes a variable power supply, and the variable power supply includes one terminal connected to the first ring through the first feed line and another terminal connected to the second ring through the second feed line. 
     
     
         9 . The plasma processing apparatus according to  claim 8 , wherein the variable power supply is formed of a variable direct-current (DC) power supply. 
     
     
         10 . The plasma processing apparatus according to  claim 9 , wherein the one terminal and the other terminal of the variable power supply are a negative terminal and a positive terminal of the variable DC power supply, respectively. 
     
     
         11 . The plasma processing apparatus according to  claim 2 , wherein the power supply unit includes a first power supply and a second power supply, at least one of which is formed of a variable power supply, such that the first power supply is connected to the first ring through the first feed line, and the second power supply is connected to the second ring through the second feed line. 
     
     
         12 . The plasma processing apparatus according to  claim 11 , wherein each of the first and second power supplies is formed of a variable power supply. 
     
     
         13 . The plasma processing apparatus according to  claim 11 , wherein the variable power supply is formed of a variable DC power supply. 
     
     
         14 . The plasma processing apparatus according to  claim 11 , wherein the first power supply includes one terminal connected to the first ring and another terminal connected to a wall of the process container, and the second power supply includes one terminal connected to the second ring and another terminal connected to a wall of the process container. 
     
     
         15 . The plasma processing apparatus according to  claim 11 , wherein the first power supply includes one terminal connected to the first ring and another terminal connected to the first electrode, and the second power supply includes one terminal connected to the second ring and another terminal connected to the first electrode. 
     
     
         16 . The plasma processing apparatus according to  claim 13 , wherein a negative terminal of the variable DC power supply is connected to the first or second ring. 
     
     
         17 . The plasma processing apparatus according to  claim 2 , wherein the process gas supply source is configured to supply as the process gas an etching gas for performing etching to the target substrate.