Composition for etching silicon oxide and method of forming a contact hole using the same

Abstract

In a composition for etching silicon oxide, and a method of forming a contact hole using the composition, the composition which includes from about 0.01 to about 2 percent by weight of ammonium bifluoride, from about 2 to about 35 percent by weight of an organic acid, from about 0.05 to about 1 percent by weight of an inorganic acid, and a remainder of a low polar organic solvent. The composition may reduce damages to a metal silicide pattern that may be exposed in an etching process performed for forming the contact hole.

1 . A composition for etching silicon oxide comprising:
 from about 0.01 to about 2 percent by weight of ammonium bifluoride (NH 4 HF 2 );   from about 2 to about 35 percent by weight of an organic acid;   from about 0.05 to about 1 percent by weight of an inorganic acid; and   a remainder of a low polar organic solvent,   the composition being used for enlarging a contact hole in a silicon oxide layer covering a metal silicide pattern while preventing or reducing damages to the metal silicide pattern exposed while enlarging the contact hole.   
     
     
         2 . The composition of  claim 1 , wherein the silicon oxide layer comprises a high density plasma (HDP) silicon oxide layer and a borophosphosilicate glass (BPSG) layer, and wherein the composition has an etching selectivity between the HDP silicon oxide layer and the BPSG layer in a range of from about 1:1.2 to about 1:2.5. 
     
     
         3 . The composition of  claim 1 , wherein the inorganic acid comprises at least one of hydrochloric acid (HCl), nitric acid (HNO 3 ) and sulfuric acid (H 2 SO 4 ). 
     
     
         4 . The composition of  claim 1 , wherein the organic acid comprises at least one of acetic acid, formic acid and propionic acid. 
     
     
         5 . The composition of  claim 1 , wherein the low polar organic solvent comprises at least one of dimethylformamide, dimethyl sulfoxide, acetonitrile, tetrahydrofuran and methyl ethyl ketone. 
     
     
         6 . The composition of  claim 1 , wherein the composition comprises:
 from about 0.05 to about 1 percent by weight of ammonium bifluoride;   from about 5 to about 30 percent by weight of the organic acid;   from about 0.06 to about 0.5 percent by weight of the inorganic acid; and   the remainder being the low polar organic solvent.   
     
     
         7 . The composition of  claim 1 , wherein the composition comprises:
 from about 0.1 to about 0.5 percent by weight of ammonium bifluoride;   from about 10 to about 25 percent by weight of the organic acid;   from about 0.08 to about 0.3 percent by weight of the inorganic acid; and   the remainder being the low polar organic solvent.