Method for forming pattern

Abstract

A method of forming a pattern, which comprises forming a masking material layer on a surface of a working film by coating the surface with a solution of a mixture comprising an inorganic compound having a bond between an inorganic element and oxygen atom, and a volatile unit, volatilizing the volatile unit to thereby make the masking material layer porous, forming a resist layer on a surface of the masking material layer, patterning the resist film to form a resist pattern, dry-etching the masking material layer to thereby transfer the resist pattern to the masking material layer, thereby forming a masking material pattern, and dry etching the working film to thereby transfer the masking material pattern to the working film to thereby form a working film pattern.

What is claimed is:  
     
         1 . A method of forming a pattern, which comprises: 
 forming a masking material layer on a surface of a working film by coating the surface with a solution of a mixture comprising an inorganic compound having a bond between an inorganic element and oxygen atom, and a volatile unit;    volatilizing said volatile unit to make said masking material layer porous;    forming a resist layer on a surface of said masking material layer;    subjecting said resist film to a patterning process to form a resist pattern;    dry-etching said masking material layer to thereby transfer said resist pattern to said masking material layer, thereby forming a masking material pattern; and    dry etching said working film to thereby transfer said masking material pattern to said working film to thereby form a working film pattern.    
     
     
         2 . The method according to  claim 1 , wherein said inorganic element is silicon.  
     
     
         3 . The method according to  claim 1 , wherein the volatilization of said volatile unit is performed by way of heating.  
     
     
         4 . The method according to  claim 3 , wherein said heating is performed at a temperature ranging from 100 to 500° C.  
     
     
         5 . The method according to  claim 1 , wherein the volatilization of said volatile unit is performed by way of irradiation of an energy beam.  
     
     
         6 . The method according to  claim 5 , wherein said energy beam is selected from the group consisting of an electron beam, ultraviolet rays, a visible light and X-rays.  
     
     
         7 . The method according to  claim 1 , wherein said volatile unit is a volatile additive.  
     
     
         8 . The method according to  claim 7 , wherein said volatile additive has an average molecular weight of 3000 or less.  
     
     
         9 . The method according to  claim 7 , wherein said volatile additive is selected from the group consisting of azo compounds, di-azo compounds, peroxides, alkylaryl ketone, silylperoxide, organic halides, halogen-containing compounds, orthoquinone diazide compounds, sulfone compounds, sulfonic acid compounds, nitrobenzyl compounds, a polymer or a copolymer containing as a polymeric unit at least one of amine, amino acid, sulfur dioxide, acetal and halides thereof, a polymer or a copolymer containing as a polymeric unit at least one of cresol, styrene, acrylic acid, methacrylic acid and halides thereof, and a dye selected from one of coumalin and curcumin.  
     
     
         10 . The method according to  claim 1 , wherein said volatile unit is in a state wherein it is chemically bonded with an inorganic compound.  
     
     
         11 . The method according to  claim 10 , wherein said inorganic compound with which the volatile unit is chemically bonded has a functional group of substituted or unsubstituted aliphatic or aromatic hydrocarbon with carbon number of 2 or more.  
     
     
         12 . The method according to  claim 1 , wherein said dry etching is performed using a gas containing nitrogen atoms.  
     
     
         13 . The method according to  claim 12 , wherein said gas containing nitrogen atoms is at least one kind of gas selected from the group consisting of N 2  and NH 3 .  
     
     
         14 . The method according to  claim 1 , wherein said mask material layer is turned into a porous layer by enabling the volatile unit to volatilize by making use of an etchant to be employed for dry-etching the working film.  
     
     
         15 . A method of forming a pattern, which comprises: 
 forming a masking material layer on a surface of a working film by coating the surface with a solution of a mixture comprising an inorganic compound having a bond between an inorganic element and oxygen atom, and a soluble unit;    treating said masking material layer with a solvent which is capable of dissolving said soluble unit to thereby make said masking material layer porous;    forming a resist layer on a surface of said masking material layer;    subjecting said resist film to a patterning process to form a resist pattern;    dry-etching said masking material layer to thereby transfer said resist pattern to said masking material layer, thereby forming a masking material pattern; and    dry etching said working film to thereby transfer said masking material pattern to said working film to thereby form a working film pattern.    
     
     
         16 . The method according to  claim 15 , wherein said inorganic element is silicon.  
     
     
         17 . The method according to  claim 15 , wherein said soluble unit is a soluble additive.  
     
     
         18 . The method according to  claim 17 , wherein said soluble additive has an average molecular weight of 3000 or less.  
     
     
         19 . The method according to  claim 17 , wherein said soluble additive is selected from the group consisting of azo compounds, di-azo compounds, peroxides, alkylaryl ketone, silylperoxide, organic halides, halogen-containing compounds, orthoquinone diazide compounds, sulfone compounds, sulfonic acid compounds, nitrobenzyl compounds, a polymer or a copolymer containing as a polymeric unit at least one of amine, amino acid, sulfur dioxide, acetal and halides thereof, a polymer or a copolymer containing as a polymeric unit at least one of cresol, styrene, acrylic acid, methacrylic acid and halides thereof, and a dye selected from one of coumalin and curcumin.  
     
     
         20 . The method according to  claim 15 , wherein said soluble unit is in a state wherein it is chemically bonded with an inorganic compound.  
     
     
         21 . The method according to  claim 20 , wherein said inorganic compound with which the soluble unit is chemically bonded has a functional group of substituted or unsubstituted aliphatic or aromatic hydrocarbon with carbon number of 2 or more.  
     
     
         22 . The method according to  claim 15 , wherein said dry etching is performed using a gas containing nitrogen atoms.  
     
     
         23 . The method according to  claim 22 , wherein said gas containing nitrogen atoms is at least one kind of gas selected from the group consisting of N 2  and NH 3 .  
     
     
         24 . The method according to  claim 15 , wherein said solvent is selected from the group consisting of a ketone-based solvent, a Cellosolve-based solvent, an ester-based solvent, an alcohol-based solvent, anisole, toluene, xylene, naphtha and water.