Plasma processing apparatus and method with controlled biasing functions

Abstract

Processing technique using plasma to process the surface of a sample such as semiconductor device. The phases of RF bias voltages applied to a substrate electrode and an antenna electrode opposed thereto are controlled to be opposite to each other so that either one of the electrodes is forced to always function as ground. Accordingly, current flowing to cross the magnetic field for controlling the plasma is decreased, and the potential distribution difference in the surface of the sample to be processed is reduced, so that the charging damage can be suppressed. Energy of ions incident to the sample to be processed can be controlled to perform high-precision etching. The plasma potential can also be controlled so that the strength of the ion impact to the inner wall of the chamber can be reduced, thereby reducing particles detached from the inner wall of the processing apparatus to improve the throughput.

1 - 14 . (canceled)  
   
   
       15 . A plasma processing apparatus comprising: 
 a container of which the inside is controlled to have a predetermined pressure-reduced atmosphere;    a substrate electrode on which a sample provided in said container can be placed;    an opposite electrode provided to oppose said substrate electrode;    a plasma-generating power supply connected to said opposite electrode to supply RF power thereto and for generating plasma within said container;    a plurality of biasing power supplies connected to said substrate electrode and said opposite electrode to supply thereto RF power having lower frequencies than that of said RF power for plasma generation; and    a phase controller for controlling the phases of RF voltages from said plurality of biasing power supplies.    
   
   
       16 . A plasma processing apparatus according to  claim 15 , wherein said phase controller controls the phases of said RF voltages to both said electrodes to be opposite to each other.  
   
   
       17 . A plasma processing apparatus according to  claim 15 , wherein said phase controller controls the phases of said RF voltages to both said electrodes to be the same and opposite to each other.  
   
   
       18 . A plasma processing apparatus according to  claim 15 , wherein said phases are controlled to have a difference of 0°±45° or 180°±45°.  
   
   
       19 . A plasma processing apparatus according to  claim 18 , wherein said phases are controlled to have a difference of 0°±30° or 180°±30°.  
   
   
       20 . A plasma processing apparatus according to  claim 15 , wherein said plurality of biasing power supplies generate RF power with the same frequency of 5 MHz or below.  
   
   
       21 . A plasma processing apparatus according to  claim 15 , further comprising a field generating coil for producing magnetic field in said container.  
   
   
       22 . A plasma processing apparatus comprising: 
 a process chamber connected to a vacuum exhauster for the chamber's inside pressure to be reducible;    a gas feed unit for supplying gas into said process chamber;    a substrate electrode provided within said chamber and for placing a sample on said substrate electrode;    an antenna electrode provided to oppose said substrate electrode and from which electromagnetic waves for generating plasma are radiated;    a first RF power supply connected to said antenna electrode in order to serve to generate said plasma;    a second RF power supply connected to said substrate electrode;    a third RF power supply connected to said antenna electrode; and    a phase controller for controlling the phases of RF voltages from said second and third power supplies to be opposite to each other.    
   
   
       23 - 25 . (canceled)