Etching method and etching equipment

Abstract

The invention provides an etching method for realizing trench etching without causing any damages to the side walls of the trench while maintaining a high-etching rate. The plasma etching method relates to forming a groove or a hole by forming a silicon trench to a silicon substrate or a silicon substrate having a silicon oxide dielectric layer via a mixed gas plasma containing a mixed gas of SF6 and O2 or a mixed gas of SF6, O2 and SiF4 and having added thereto a gas containing hydrogen within the range of 5 to 16% (percent concentration) of the total gas flow rate of the mixed gas.

1 . An etching method for forming a trench (a groove or a hole) to a silicon substrate or a silicon substrate having a silicon oxide dielectric layer, the etching performed via a plasma generated by a mixed gas formed by adding a gas containing hydrogen to a mixed gas composed of SF6 and O2 or a mixed gas composed of SF6, O2 and SiF4, wherein the amount of added gas containing hydrogen is within a range of 5 to 16% (percent concentration) of the total gas flow rate of said mixed gas composed of SF6 and O2 or said mixed gas composed of SF6, O2 and SiF4.  
   
   
       2 . The etching method according to  claim 1 , wherein 
 said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3.    
   
   
       3 . The etching method according to  claim 1 , wherein 
 said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3 being diluted by Ar, He or N2 when being added to the mixed gas, or said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3 being diluted in advance by said gases.    
   
   
       4 . The etching method according to  claim 1 , wherein 
 said gas containing hydrogen does not contain carbon or fluorine.    
   
   
       5 . The etching method according to  claim 1 , wherein a temperature of a sample stage for holding the silicon substrate or the silicon substrate having the silicon oxide dielectric layer is controlled to 0 deg. C. or lower.  
   
   
       6 . An etching equipment for forming a trench (a groove or a hole) to a silicon substrate or a silicon substrate having a silicon oxide dielectric layer via a plasma generated by a mixed gas, the etching equipment comprising: 
 a gas feeding unit for feeding the mixed gas formed by adding a gas containing hydrogen to a mixed gas composed of SF6 and O2 or a mixed gas composed of SF6, O2 and SiF4, wherein the amount of added gas containing hydrogen is within a range of 5 to 16% (percent concentration) of the total gas flow rate of said mixed gas composed of SF6 and O2 or said mixed gas composed of SF6, O2 and SiF4; and    a sample stage for holding the silicon substrate or the silicon substrate having a silicon oxide dielectric layer.    
   
   
       7 . The etching equipment according to  claim 6 , wherein 
 said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3.    
   
   
       8 . The etching equipment according to  claim 6 , wherein 
 said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3 being diluted by Ar, He or N2 when being added to the mixed gas, or said gas containing hydrogen is HBr, HI, HCl, H2, H2O or NH3 being diluted in advance by said gases.    
   
   
       9 . The etching equipment according to  claim 6 , wherein 
 said gas containing hydrogen does not contain carbon or fluorine.    
   
   
       10 . The etching equipment according to  claim 6 , wherein a temperature of the sample stage for holding the silicon substrate or the silicon substrate having the silicon oxide dielectric layer is controlled to 0 deg. C. or lower.