Plasma processing apparatus

Abstract

A plasma processing apparatus is disclosed in which a wafer mounted on a sample stage arranged in a processing chamber in a vacuum vessel is processed using a plasma formed in the processing chamber. A dielectric bell jar makes up the upper part of the vacuum vessel and surrounds processing chamber. A coil-shaped antenna wound on the outer periphery of the bell jar is supplied with the high-frequency power to form the plasma. A Faraday shield of a conductive material is formed of double layers including inner and outer layers arranged in spaced relation to each other between the antenna and the bell jar, each layer having a plurality of slits and set at a predetermined potential. The slits of the inner and outer layers of the Faraday shield are arranged in staggered fashion.

1 . A plasma processing apparatus in which a wafer placed on a sample stage arranged in a processing chamber in a vacuum vessel is processed using the plasma formed in the processing chamber, comprising:
 a bell jar of an insulating material making up the upper part of the vacuum vessel and surrounding the processing chamber;   a coil-shaped antenna wound on the outer periphery of the bell jar and supplied with the high-frequency power to form the plasma; and   a Faraday shield of a conductive material arranged in double layers inside and outside with a gap between the antenna and the bell jar, each layer having a plurality of slits and set at a predetermined potential;   wherein the slits of the outer and inner layers of the Faraday shield are arranged in staggered fashion so that the slits of one of the outer and inner layers of the Faraday shield cover the film portions of the other of the outer and inner layers of the Faraday shield.   
     
     
         2 . The plasma processing apparatus according to  claim 1 ,
 wherein the Faraday shield is formed of a plurality of film layers arranged on the outer peripheral wall surface of the bell jar.   
     
     
         3 . The plasma processing apparatus according to  claim 1 ,
 wherein the high-frequency power is supplied to the Faraday shield.   
     
     
         4 . The plasma processing apparatus according to  claim 1 ,
 wherein the film portions between the adjacent slits of the outer layer of the Faraday shield are arranged to cover the whole gap of the slits of the inner layer of the Faraday shield along the peripheral direction of the wafer.   
     
     
         5 . The plasma processing apparatus according to  claim 1 ,
 wherein an insulative film is arranged between the inner and outer layers of the Faraday shield.   
     
     
         6 . The plasma processing apparatus according to  claim 1 ,
 wherein selected one of the inner and outer layers of the Faraday shield is formed by spraying.   
     
     
         7 . A plasma processing apparatus comprising:
 a sample stage arranged in a processing chamber in an internally decompressed processing vessel and having a circular wafer mounted thereon;   a bell jar of an insulating material making up the upper part of the processing vessel and surrounding the outer periphery of the sample stage above the sample stage;   a coil-shaped antenna wound to surround the sample stage on the outside of the outer wall surface of the bell jar;   a power supply for supplying the high-frequency power to the antenna;   a filmy Faraday shield arranged between the bell jar and the antenna and set to a predetermined potential; and   an exhaust means coupled to the lower part of the processing vessel and arranged to communicate with the processing chamber;   wherein the Faraday shield includes inner and outer layers arranged in spaced relation to each other, each layer having a plurality of slits, and the film portions between the plurality of the slits of the inner and outer layers of the Faraday shield are arranged in staggered fashion so that the film portions between the slits of one of the inner and outer layers cover the slits of the other layer of the Faraday shield.   
     
     
         8 . The plasma processing apparatus according to  claim 7 ,
 wherein the high-frequency power is supplied to the Faraday shield.   
     
     
         9 . The plasma processing apparatus according to  claim 7 ,
 wherein the film portions between the adjacent slits of the outer layer of the Faraday shield are arranged to cover the slits of the inner layer of the Faraday shield over the whole peripheral gap of the wafer.   
     
     
         10 . The plasma processing apparatus according to  claim 7 ,
 wherein a film of an insulating material is arranged between the inner and outer layers of the Faraday shield.   
     
     
         11 . The plasma processing apparatus according to  claim 7 ,
 wherein selected one of the inner and outer layers of the Faraday shield is formed by spraying.