Plasma processing apparatus and plasma processing method

Abstract

Advantages of a conventional upper electrode DC power applying manner can be maintained and disadvantages of the upper electrode DC power applying manner can be removed. In a capacitively coupled plasma processing apparatus, a first high frequency power RF H for plasma generation and a second high frequency power RF L for ion attraction are overlapped with each other to be applied to a susceptor (lower electrode) 16 . Further, an AC power having a preset frequency is applied to an upper electrode 46 via a matching unit 66 and a blocking capacitor 68 from an AC power supply 64 . Furthermore, the AC power has a frequency, which ions in plasma can follow, and the AC power supply 64 can vary a power, a voltage peak value, or an effective value the AC power.

1 . A plasma processing apparatus comprising:
 a processing chamber allowed to be vacuum exhausted;   a first electrode that is provided within the processing chamber and configured to mount and support thereon a target substrate;   a second electrode that is provided to be parallel with the first electrode with a preset gap within the processing chamber;   a processing gas supply unit configured to supply a predetermined processing gas into a processing space between the first electrode and the second electrode within the processing chamber;   a first high frequency power supply configured to apply a first high frequency power having a frequency for electrically discharging the processing gas and generating plasma to the first electrode;   an AC power supply configured to apply a low frequency or a high frequency AC power having a frequency, which an ion in the plasma is allowed to follow, to the second electrode; and   a blocking capacitor connected between the AC power supply and the second electrode.   
     
     
         2 . The plasma processing apparatus of  claim 1 ,
 wherein the frequency of the AC power is lower than an ion plasma frequency of the ion.   
     
     
         3 . The plasma processing apparatus of  claim 1 , further comprising:
 a second high frequency power supply configured to apply a second high frequency power having a frequency for ion attraction to the first electrode.   
     
     
         4 . The plasma processing apparatus of  claim 3 ,
 wherein the frequency of the first high frequency power is equal to or larger than about 40 MHz, and the frequency of the second high frequency power is equal to or smaller than about 13 MHz and is higher than an ion plasma frequency of the ion.   
     
     
         5 . A plasma etching method of forming a hole of a high aspect ratio in a silicon oxide film on a target substrate, the plasma etching method comprising:
 mounting and supporting the target substrate on a first electrode within a processing chamber in which the first electrode is provided to be parallel with a second electrode with a preset gap;   vacuum exhausting an inside of the processing chamber to a preset pressure;   generating plasma of a fluorocarbon-based etching gas in a processing space between the first electrode and the second electrode by supplying the etching gas into the processing space and applying a first high frequency power to the first electrode; and   applying a low frequency AC power or a high frequency AC power having a frequency, which an ion in the plasma is allowed to follow, to the second electrode via a blocking capacitor.   
     
     
         6 . The plasma etching method of  claim 5 ,
 wherein a second high frequency power having a frequency for ion attraction is applied to the first electrode.   
     
     
         7 . The plasma etching method of  claim 5 ,
 wherein the etching gas contains a fluorocarbon gas, an argon gas, and an oxygen gas.   
     
     
         8 . The plasma etching method of  claim 5 ,
 wherein a base material of the second electrode contains silicon.