Dry etching gas composition comprising sulfur-containing fluorocarbon compound and dry etching method using the same

Abstract

Provided is a novel etching gas composition that comprises a sulfur-containing compound and that can selectively etch SiO2 over low dielectric constant materials (low-k materials; SiON, SiCN, SiOCN, SiOC).A dry etching gas composition comprises a saturated and cyclic sulfur-containing fluorocarbon compound that is represented by general formula (1) of CxFySz where x, y, and z are 2≤x≤5, y≤2x, and 1≤z≤2.

1 . A dry etching gas composition comprising a saturated and cyclic sulfur-containing fluorocarbon compound that is represented by general formula (1) of C x F y S z  wherein x, y, and z are 2≤x≤5, y≤2x, and 1≤z≤2. 
     
     
         2 . The dry etching gas composition according to  claim 1 , wherein the sulfur-containing fluorocarbon compound is 2,2,3,3,4,4,5,5-octafluorotetrahydrothiophene (C 4 F 8 S). 
     
     
         3 . The dry etching gas composition according to  claim 1 , comprising the sulfur-containing fluorocarbon compound in an amount of 1 to 100 vol %. 
     
     
         4 . The dry etching gas composition according to  claim 1 , further comprising, in addition to the sulfur-containing fluorocarbon compound, at least one oxygen-containing compound selected from the group consisting of O 2 , O 3 , CO, CO 2 , NO, NO 2 , SO 2 , and SO 3 . 
     
     
         5 . The dry etching gas composition according to  claim 1 , further comprising, in addition to the sulfur-containing fluorocarbon compound, at least one inert gas selected from the group consisting of N 2 , He, Ar, Ne, and Xe. 
     
     
         6 . A dry etching method comprising plasma etching, by using the dry etching gas composition according to  claim 1 , a stacked structure containing at least two or more selected from the group consisting of (a1) a carbon-containing silicon-based film, (a2) a crystalline silicon film, (a3) an amorphous silicon film, (a4) a polycrystalline silicon film (polysilicon film), (a5) a silicon oxynitride film, (a6) an amorphous carbon film, (a7) a photoresist film, (a8) a silicon oxide film, and (a9) a silicon nitride film, thereby individually or simultaneously selectively etching films excluding (a6) the amorphous carbon film and (a7) the photoresist film. 
     
     
         7 . A dry etching method comprising plasma etching, by using the dry etching gas composition according to  claim 1 , a stacked structure containing at least two or more selected from the group consisting of (a1) a carbon-containing silicon-based film, (a2) a crystalline silicon film, (a3) an amorphous silicon film, (a4) a polycrystalline silicon film (polysilicon film), (a5) a silicon oxynitride film, (a6) an amorphous carbon film, (a7) a photoresist film, and (a8) a silicon oxide film, thereby selectively etching (a8) the silicon oxide film alone. 
     
     
         8 . The dry etching method according to  claim 6 , wherein etching is performed by generating a plasma of the etching gas composition comprising a saturated and cyclic sulfur-containing fluorocarbon compound that is represented by general formula (1) of C x F y S z  wherein x, y, and z are 2≤x≤5, y≤2x, and 1≤z≤2 to form S-containing ions or active species. 
     
     
         9 . The dry etching method according  claim 6 , wherein etching by the dry etching gas composition comprising a saturated and cyclic sulfur-containing fluorocarbon compound that is represented by general formula (1) of C x F y S z  wherein x, y, and z are 2≤x≤5, y≤2x, and 1≤z≤2 is performed under plasma conditions that enable simultaneous etching of (b1) a silicon oxide film and (b2) a silicon nitride film.