Plasma processing apparatus and method

Abstract

An apparatus includes an upper electrode and a lower electrode for supporting a wafer disposed opposite each other within a process chamber. A first RF power supply configured to apply a first RF power having a relatively higher frequency is connected to the upper electrode. A second RF power supply configured to apply a second RF power having a relatively lower frequency is connected to the lower electrode. A variable DC power supply is connected to the upper electrode. A process gas is supplied into the process chamber while any one of application voltage, application current, and application power from the variable DC power supply to the upper electrode is controlled, to generate plasma of the process gas so as to perform plasma etching.

1 . (canceled) 
     
     
         2 . A plasma processing apparatus comprising:
 a process container that forms a process space to accommodate a target substrate;   an exhaust unit connected to an exhaust port of the process container to vacuum-exhaust gas from inside the process container;   an exhaust plate interposed between the process space and the exhaust port to rectify a flow of exhaust gas;   a first electrode and a second electrode disposed opposite each other within 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;   a first RF power application unit configured to apply a first RF power to the first electrode;   a second RF power application unit 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 DC power supply configured to apply a DC voltage to the first electrode;   a process gas supply unit configured to supply a process gas into the process container;   a control unit configured to control any one of application voltage, application current, and application power from the DC power supply to the first electrode; and   a conductive member disposed within the process container and configured to be grounded to release through plasma a current caused by the DC voltage applied from the DC power supply to the first electrode, the conductive member being disposed as a ring around the first electrode.   
     
     
         3 . The plasma processing apparatus according to  claim 2 , further comprising a switching mechanism that connects the conductive member to a ground potential portion when a plasma process is performed on the target substrate, and connects the conductive member to a negative potential portion when plasma cleaning is performed on the conductive member. 
     
     
         4 . The plasma processing apparatus according to  claim 3 , wherein the switching mechanism connects the first electrode to a negative terminal of the DC power supply when the plasma process is performed on the target substrate, and connects the conductive member to the negative terminal of the DC power supply when the plasma cleaning is performed on the conductive member. 
     
     
         5 . The plasma processing apparatus according to  claim 4 , wherein the switching mechanism connects the first electrode to a positive terminal of the DC power supply when the plasma cleaning is performed on the conductive member. 
     
     
         6 . The plasma processing apparatus according to  claim 5 , further comprising a switch configured to selectively ground the positive terminal of the DC power supply, wherein, when the plasma process is performed on the target substrate, the switch grounds the positive terminal of the DC power supply, and the switching mechanism connects the conductive member to the positive terminal of the DC power supply. 
     
     
         7 . The plasma processing apparatus according to  claim 2 , wherein the DC power supply is configured such that any one of the application voltage, application current, and application power to the first electrode is variable. 
     
     
         8 . The plasma processing apparatus according to  claim 2 , wherein the control unit is configured to control whether the DC voltage is to be applied or not, from the DC power supply to the first electrode. 
     
     
         9 . The plasma processing apparatus according to  claim 2 , further comprising a detector configured to detect a generated plasma state, wherein the control unit controls any one of the application voltage, application current, and application power from the DC power supply to the first electrode, based on information from the detector. 
     
     
         10 . The plasma processing apparatus according to  claim 2 , wherein the first RF power has a frequency of 13.56 MHz or more. 
     
     
         11 . The plasma processing apparatus according to  claim 10 , wherein the first RF power has a frequency of 40 MHz or more. 
     
     
         12 . The plasma processing apparatus according to  claim 2 , wherein the second RF power has a frequency of 13.56 MHz or less. 
     
     
         13 . The plasma processing apparatus according to  claim 2 , wherein the DC power supply is configured to apply a voltage within a range of −2,000 to +1,000V. 
     
     
         14 . The plasma processing apparatus according to  claim 2 , wherein the DC voltage applied from the DC power supply has an absolute value of 500V or more. 
     
     
         15 . The plasma processing apparatus according to  claim 2 , wherein the DC voltage is a negative voltage having an absolute value larger than that of a self-bias voltage generated on a surface of the first electrode by the first RF power applied to the first electrode. 
     
     
         16 . The plasma processing apparatus according to  claim 2 , wherein a surface of the first electrode facing the second electrode is made of a silicon-containing substance. 
     
     
         17 . The plasma processing apparatus according to  claim 2 , wherein a cover plate is disposed to partly cover the conductive member, and the cover plate is moved relative to the conductive member by a driving mechanism to change a portion of the conductive member to be exposed to plasma. 
     
     
         18 . The plasma processing apparatus according to  claim 2 , wherein a cover film having a stepped shape and made of a material to be etched by plasma is disposed to partly cover the conductive member, and the cover film is configured to be etched to change a portion of the conductive member to be exposed to plasma.