Plasma processing apparatus

Abstract

This application discloses a practical plasma processing apparatus capable of plasma confinement without plasma-density non-uniformity and electric power loss. The apparatus comprises a plasma shield that surrounds a plasma generation region to prevent plasma from diffusing. The shield has at least one opening. The apparatus comprises a diffusion prevention electrode for preventing the plasma from diffusing through the opening of the plasma shield. The surface of the plasma shield exposed to the plasma is made of insulator. The diffusion prevention electrode is located where electrons diffusing toward the opening or having diffused through the opening from the plasma flow into itself.

What is claimed is:  
     
         1 . A plasma processing apparatus, comprising: 
 a process chamber;    a pumping line connected with an evacuation hole provided at a wall of the process chamber;    a gas introduction line connected with a gas-introduction hole provided at a wall of the process chamber to introduce a gas into a plasma generation region in the process chamber;    a plasma generator for generating plasma at the plasma generation region by applying energy to the introduced gas;    a substrate holder that is provided in the process chamber and comprises a surface on which a substrate to be processed by the plasma is held;    a plasma shield that surrounds the plasma generation region to prevent the plasma from diffusing and has at least one opening; and    a diffusion prevention electrode for preventing the plasma from diffusing through the opening of the plasma shield;    a surface of the plasma shield exposed to the plasma being made of insulator; and    the diffusion prevention electrode being located where electrons diffusing from the plasma toward the opening of the shield flow into itself.    
     
     
         2 . A plasma processing apparatus as claimed in  claim 1;   the plasma generator comprising an opposite electrode facing to the substrate holder;    the plasma generation region being between the substrate holder and the opposite electrode, and    the diffusion prevention electrode being located at a position with a distance longer than the surface of the substrate holder on which the substrate is held, from the opposite electrode.    
     
     
         3 . A plasma processing apparatus as claimed in  claim 1 , the diffusion prevention electrode being grounded.  
     
     
         4 . A plasma processing apparatus as claimed in  claim 1 , 
 further comprising a source to apply voltage to the diffusion prevention electrode.    
     
     
         5 . A plasma processing apparatus as claimed in  claim 1 , 
 the diffusion prevention electrode being made of material not contaminating process property.    
     
     
         6 . A plasma processing apparatus as claimed in  claim 5 , 
 the gas being carbon fluoride gas,    the process being plasma etching, and    the diffusion prevention electrode being made of carbon.    
     
     
         7 . A plasma processing apparatus as claimed in  claim 5 , 
 the substrate being made of silicon, and    the diffusion prevention electrode being made of silicon.    
     
     
         8 . An plasma processing apparatus, comprising: 
 a process chamber;    a pumping line connected with an evacuation hole provided at a wall of the process chamber;    a gas introduction line connected with a gas-introduction hole provided at a wall of the process chamber to introduce a gas into a plasma generation region in the process chamber;    a plasma generator for generating plasma at the plasma generation region by applying energy to the introduced gas;    a substrate holder that is provided in the process chamber and comprises a surface on which a substrate to be processed by the plasma is held;    a plasma shield that surrounds the plasma generation region to prevent the plasma from diffusing and has at least one opening; and    a diffusion prevention electrode for preventing the plasma from diffusing through the opening of the plasma shield;    a surface of the plasma shield exposed to the plasma being made of insulator; and    the diffusion prevention electrode being located where electrons having diffused from the plasma through the opening of the shield flow into itself.    
     
     
         9 . A plasma processing apparatus as claimed in  claim 8 , 
 the plasma generator comprising an opposite electrode facing to the substrate holder,    the plasma generation region being between the substrate holder and the opposite electrode, and    the diffusion prevention electrode being located at a position with a distance longer than the surface of the substrate holder on which the substrate is held, from the opposite electrode.    
     
     
         10 . A plasma processing apparatus as claimed in  claim 8 , 
 the diffusion prevention electrode being grounded.    
     
     
         11 . A plasma processing apparatus as claimed in  claim 8 , 
 further comprising a source to apply voltage to the diffusion prevention electrode.    
     
     
         12 . A plasma processing apparatus as claimed in  claim 8 , 
 the diffusion prevention electrode being made of material not contaminating process property.    
     
     
         13 . A plasma processing apparatus as claimed in  claim 12 , 
 the gas being carbon fluoride gas,    the process being plasma etching, and    the diffusion prevention electrode being made of carbon.    
     
     
         14 . A plasma processing apparatus as claimed in  claim 12 , 
 the substrate being made of silicon, and    the diffusion prevention electrode being made of silicon.