Method of dry etching organic SOG film

Abstract

Disclosed herein is a via hole dry etching method using an organic SOG film as an interlayer dielectric having low-K. In the dry etching method, a mixed gas containing at least C4F8 and O2 is used as an etching gas and an O2/(C4F8+O2) mixture ratio is set to 50% or less, thereby to carry out via hole dry etching. Further, the via hole dry etching is carried out by using a mixed gas containing at least CF4, CHF3 and N 2 and setting the quantity of flow of N 2 to above 10% and below 80% of the quantity of flow of CF4+CHF3+N2.

What is claimed is:  
     
         1 . A method of dry etching an insulating film composed of an organic SOG film by a mixed gas containing at least C4F8 and O2, comprising the following step of: 
 setting a flow rate of O2 to 50% or less of a flow rate of C4F8+O2.    
     
     
         2 . The method according to  claim 1 , wherein said dry etching is done to form a contact hole.  
     
     
         3 . The method according to  claim 1 , wherein said organic SOG film is formed by adding an alkyl group to oxide silicon.  
     
     
         4 . A method of dry etching an insulating film composed of an organic SOG film by a mixed gas containing at least CF4, CHF3 and N2, comprising the following step of setting 
 a flow rate of N2 to above 10% and below 80% of a flow rate of CF4+CHF3+N2.    
     
     
         5 . The method according to  claim 4 , wherein said dry etching is done to form a contact hole.  
     
     
         6 . The method according to  claim 4 , wherein said organic SOG film is formed by adding an alkyl group to oxide silicon.  
     
     
         7 . A dry etching method, comprising the following step of: 
 forming contact holes in an insulating film composed of an organic SOG film, and    wherein plasma treatment for removing a resist pattern used to form said each contact hole is done by using O2+N2H2.    
     
     
         8 . The dry etching method according to  claim 7 , wherein said organic SOG film is formed by adding an alkyl group to oxide silicon.  
     
     
         9 . A dry etching method, comprising the following step of: 
 forming contact holes in an insulating film composed of an organic SOG film, and    wherein plasma treatment for removing a resist pattern used to form said each contact hole is done by using O2+N2+H2.    
     
     
         10 . The dry etching method according to  claim 9 , wherein said organic SOG film is formed by adding an alkyl group to oxide silicon.  
     
     
         11 . A dry etching method, comprising the following step of: 
 forming contact hole in an insulating film composed of an organic SOG film; and    wherein plasma treatment for removing a resist pattern used to form said each contact hole is done by mixing an oxygen gas with a gas for nitriding the organic SOG film.