Plasma processing apparatus and method

Abstract

A plasma processing apparatus ands a plasma processing method of excellent mass production stability by controlling deposition films deposited on the wall of a vacuum vessel are provided. This apparatus comprises a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas, a bell jar covering a portion above the gas ring to define a vacuum processing chamber, an antenna, disposed above the bell jar, for supplying RF electric fields into the vacuum processing chamber to form plasmas, a sample table for placing a sample in the vacuum processing chamber, a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage, and a deposition preventive plate attached detachably to the inner surface of the gas ring excluding the blowing port for the processing gas. The area of the inner surface of the gas ring including the deposition preventive plate that can be viewed from the sample surface is set to about ½ or more of the area of the sample.

What is claimed is:  
     
         1 . A plasma processing apparatus comprising: 
 a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas;    a bell jar covering a portion above the gas ring to define a vacuum processing chamber;    an antenna, disposed above the bell jar, for supplying a RF electric field into the vacuum processing chamber to form plasmas;    a sample table for placing a sample in the vacuum processing chamber;    a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage; and    a deposition preventive plate attached detachably to the inner surface of the gas ring excluding the blowing port for the processing gas;    wherein an area of the inner surface of the gas ring including the deposition preventive plate that can be viewed from the sample surface is set to about ½ or more of the area of the sample.    
     
     
         2 . A plasma processing apparatus as defined in  claim 1 , wherein the deposition preventive plate has an opening for allowing the processing gas introduced from the blowing port to pass therethrough, and the opening is opened at a view angle of about 30° at the blowing port of the processing gas.  
     
     
         3 . A plasma processing apparatus as defined in  claim 1 , wherein the deposition preventive plate is disposed at a portion, of the inner surface of the bell jar, substantially corresponding to a Faraday shield not-disposed surface of the outer surface of the bell jar.  
     
     
         4 . A plasma processing apparatus as defined in  claim 1 , wherein the deposition preventive plate is made of an insulator and disposed at a portion, of the inner surface of the bell jar, substantially corresponding to a Faraday shield not-disposed surface of the outer surface of the bell jar.  
     
     
         5 . A plasma processing apparatus comprising: 
 a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas;    a bell jar covering a portion above the gas ring to define a vacuum processing chamber;    an antenna, disposed above the bell jar, for supplying an RF electric field into the vacuum processing chamber to form plasmas;    a sample table for placing a sample in the vacuum processing chamber;    a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage; and    a deposition preventive plate attached detachably at least to the inner surface of the gas ring excluding the blowing port for the processing gas;    wherein the area of the inner surface of the gas ring including the deposition preventive plate that can be viewed from the sample surface is set to about ½ or more of the area of the sample; and    wherein the apparatus further comprises a susceptor made of a dielectric material covering the outer surface and the outer lateral side of the sample table and a metal film disposed on the surface of the susceptor, in which an RF voltage is applied to the metal film to provide the surface of the susceptor with a bias voltage.    
     
     
         6 . A plasma processing apparatus comprising: 
 a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas;    a bell jar covering a portion above the gas ring to define a vacuum processing chamber;    an antenna, disposed above the bell jar, for supplying an RF electric field into the vacuum processing chamber to form plasmas;    a sample table for placing a sample in the vacuum processing chamber;    a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage; and    a deposition preventive plate attached detachably at least to the inner surface of the gas ring excluding the    an antenna, disposed above the bell jar, for supplying an RF electric field into the vacuum processing chamber to form plasmas;    a sample table for placing a sample in the vacuum processing chamber;    a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage; and    an RF power source circuit for supplying a power source voltage to the antenna and the Faraday shield,    the RF power source circuit comprising an RF power source, an antenna connected with the RF power source, a resonance circuit connected in series with the antenna and supplying a resonance voltage thereof as an RF bias voltage to the Faraday shield, a detection circuit for detecting the resonance voltage of the resonance circuit, and a comparator circuit for comparing the resonance voltage detected by the detection circuit with a predetermined set value;    wherein a constant of the resonance circuit is changed based on the result of comparison by the comparison circuit.    
     
     
         10 . A plasma processing method for a plasma processing apparatus comprising: 
 a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas;    a bell jar covering a portion above the gas ring to define a vacuum processing chamber;    an antenna, disposed above the bell jar, for supplying an RF electric field into the vacuum processing chamber to form plasmas;    a sample table for placing a sample in the vacuum processing chamber;    a Faraday shield disposed between the antenna and the bell jar and applied with an RF bias voltage;    a deposition preventive plate attached detachably at least to the inner surface of the gas ring excluding the blowing port for the processing gas and having an area at least ½ or more of the area of the sample;    a susceptor made of a dielectric material covering the outer surface and the lateral side of the plating table, an electrode disposed on the inner surface or on a side of the inner surface of the susceptor and an RF bias power source circuit for applying the RF voltage to the electrode to provide the surface of the susceptor with a bias voltage,    the RF bias power source circuit comprising a circuit for supplying the RF voltage power source by way of a variable capacitor to the electrode, a detection circuit for detecting the electrode voltage, and a comparator circuit for comparing the voltage detected by detection circuit with a predetermined set value;    wherein a constant of the variable capacitor is changed based on the result of comparison by the comparison circuit. blowing port for the processing gas;    wherein the area of the inner surface of the gas ring including the deposition preventive plate that can be viewed from the sample surface is set to about ½ or more of the area of the sample; and    wherein the apparatus further comprises a susceptor made of a dielectric material covering the outer surface and the outer lateral side of the sample table and a metal film disposed in the inside of the susceptor, in which an RF voltage is applied to the metal to provide the surface of the susceptor with a bias voltage.    
     
     
         7 . A plasma processing apparatus as defined in  claim 5  or  6 , wherein the metal film is connected with a conductive portion of the sample table.  
     
     
         8 . A plasma processing apparatus as defined in  claim 5  or  6 , wherein the sample table is made of an insulator and has, at the inside thereof, an electrode for application of a susceptor bias connected to a metal film with the susceptor is formed in the inside thereof.  
     
     
         9 . A plasma processing method for a plasma processing apparatus comprising: 
 a gas ring forming a portion of a vacuum processing chamber and having a blowing port for a processing gas;    a bell jar covering a portion above the gas ring to define a vacuum processing chamber;