Etching gas composition for silicon oxide and method of etching silicon oxide using the same

Abstract

Disclosed are an etching gas composition for etching silicon oxide and a method of etching silicon oxide using the same. The etching gas composition for etching silicon oxide consists essentially of a carbon fluoride gas, in which the ratio of fluorine atoms relative to carbon atoms is less than 2, and an auxiliary fluorohydrocarbon gas comprising hydrogen, fluorine and carbon atoms. Silicon oxide is etched efficiently and precisely by utilizing a plasma of the etching gas composition. The etching selectivity of an oxide layer formed of silicon oxide with respect to photoresisit is thereby increased. Even when a thin photoresist layer wherein solubility into water changes by a light having DUV wavelength is applied, a contact hole having a high aspect ratio and a good profile can be manufactured using the etching compositions and methods of the present invention.

1 . An etching gas composition for etching silicon oxide comprising a mixture of carbon fluoride gas in which the ratio of fluorine atoms relative to carbon atoms is less than 2 and an auxiliary gas including hydrogen, fluorine and carbon atoms.  
     
     
         2 . An etching gas composition as claimed in  claim 1  wherein the carbon fluoride compound includes a double carbon-carbon bond or a triple carbon-carbon bond.  
     
     
         3 . An etching gas composition as claimed in  claim 1  wherein said carbon fluoride gas is at least one member selected from the group consisting of C 5 F 8 , C 4 F 6 , C 3 F 4  and C 2 F 2 , and mixtures thereof.  
     
     
         4 . An etching gas composition as claimed in  claim 1  wherein said auxiliary gas is at least one member selected from the group consisting of CH 2 F 2  and CHF 3 , and mixtures thereof.  
     
     
         5 . An etching gas composition as claimed in  claim 1  wherein the volumetric ratio of said auxiliary gas with respect to said carbon fluoride gas is in a range of about 0.1-3.0.  
     
     
         6 . An etching gas composition as claimed in  claim 1  wherein said etching gas composition further comprises CO.  
     
     
         7 . An etching gas composition as claimed in  claim 6  wherein the volumetric ratio of said CO with respect to said carbon fluoride gas is in a range of about 1-30.  
     
     
         8 . An etching gas composition as claimed in  claim 1  further comprising an inert gas and oxygen.