Etching Gas

Abstract

Disclosed is an etching gas provided containing CHF 2 COF. The etching gas may contain, as an additive, at least one kind of gas selected from O 2 , O 3 , CO, CO 2 , F 2 , NF 3 , Cl 2 , Br 2 , I 2 , XF n (In this formula, X represents Cl, I or Br. n represents an integer satisfying 1≦n≦7.), CH 4 , CH 3 F, CH 2 F 2 , CHF 3 , N 2 , He, Ar, Ne, Kr and the like, from CH 4 , C 2 H 2 ,C 2 H 4 ,C 2 H 6 , C 3 H 4 , C 3 H 6 , C 3 H 5 , HI, HBr, HCl, CO, NO, NH 3 , H 2 and the like, or from CH 4 , CH 3 F, CH 2 F 2 and CHF 3 . This etching gas is not only excellent in etching performances such as the selection ratio to a resist and the patterning profile but also easily available and does not substantially by-produce CF 4 that places a burden on the environment.

1 . An etching gas used for etching semiconductors, dielectric substances or thin films formed of metals, comprising:
 CHF 2 COF.   
     
     
         2 . An etching gas as claimed in  claim 1 , wherein the semiconductors or the dielectric substances are a silicon-containing substance. 
     
     
         3 . An etching gas as claimed in  claim 1 , wherein the etching gas contains at least one kind of gas selected from O 2 , O 3 , CO, CO 2 , F 2 , NF 3 , Cl 2 , Br 2 , I 2 , XF n  (In this formula, X represents Cl, I or Br. n represents an integer satisfying 1≦n≦7.), CH 4 , CH 3 F, CH 2 F 2 , CHF 3 , N 2 , He, Ar, Ne and Kr, as an additive. 
     
     
         4 . An etching gas as claimed in  claim 1 , wherein the etching gas contains at least one kind of gas selected from CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , C 3 H 4 , C 3 H 6 , C 3 H 8 , HI, HBr, HCl, CO, NO, NH 3 , H 2 , N 2 , He, Ar, Ne and Kr, as an additive. 
     
     
         5 . An etching gas as claimed in  claim 1 , wherein the etching gas contains at least one kind of gas selected from CH 4 , CH 3 F, CH 2 F 2 , CHF 3 , as an additive. 
     
     
         6 . A method for etching semiconductor films, dielectric films or metal films, comprising the step of:
 using an etching gas as claimed in  claim 1 .   
     
     
         7 . A method for etching, as claimed in  claim 6 , further comprising the step of:
 thereafter ashing by F 2  or O 2 .