Supercritical carbon dioxide/chemical formulation for ashed and unashed aluminum post-etch residue removal

Abstract

A post-etch residue cleaning composition for cleaning ashed or unashed aluminum/SiN/Si post-etch residue from small dimensions on semiconductor substrates. The cleaning composition contains supercritical CO 2 (SCCO2), alcohol, fluoride source, an aluminum ion complexing agent and, optionally, corrosion inhibitor. Such cleaning composition overcomes the intrinsic deficiency of SCCO2 as a cleaning reagent, viz., the non-polar character of SCCO2 and its associated inability to solubilize species such as inorganic salts and polar organic compounds that are present in the post-etch residue and that must be removed from the semiconductor substrate for efficient cleaning. The cleaning composition enables damage-free, residue-free cleaning of substrates having ashed or unashed aluminum/SiN/Si post-etch residue thereon.

1 - 44 . (canceled)  
   
   
       45 . A post-etch residue cleaning composition, comprising SCCO2, alcohol, fluorine source, an aluminum ion complexing agent and, optionally, corrosion inhibitor.  
   
   
       46 . The composition of  claim 45 , wherein the alcohol comprises at least one C 1 -C 4  alcohol.  
   
   
       47 . The composition of  claim 45 , wherein the alcohol comprises methanol.  
   
   
       48 . The composition of  claim 45 , wherein the fluorine source comprises a fluorine-containing compound selected from the group consisting of hydrogen fluoride (HF), amine trihydrogen fluoride compounds of the formula NR 3 (HF) 3  wherein each R is independently selected from hydrogen and lower alkyl, hydrogen fluoride-pyridine (pyr-HF), and ammonium fluorides of the formula R 4 NF, wherein each R is independently selected from hydrogen and lower alkyl.  
   
   
       49 . The composition of  claim 45 , wherein the fluorine source comprises ammonium fluoride (NH 4 F).  
   
   
       50 . The composition of  claim 45 , wherein the aluminum ion complexing agent comprises a complexing agent selected from the group consisting of salicylic acid, EDTA, oxalic acid, beta-diketones, gallic acid, nitrilotriacetic acid, 3-hydroxy-2-naphthoic acid, and oxine.  
   
   
       51 . The composition of  claim 45 , wherein the aluminum ion complexing agent comprises salicylic acid.  
   
   
       52 . The composition of  claim 45 , comprising corrosion inhibitor.  
   
   
       53 . The composition of  claim 52 , wherein said corrosion inhibitor includes boric acid.  
   
   
       54 . The composition of  claim 45 , wherein the alcohol has a concentration that increases the solubility of the composition for inorganic salts and polar organic compounds present in aluminum/SiN/Si post-etch residue, relative to a corresponding composition lacking such alcohol.  
   
   
       55 . The composition of  claim 49 , comprising ammonium fluoride, salicylic acid and boric acid.  
   
   
       56 . The composition of  claim 55 , wherein ammonium fluoride has a concentration of from about 0.01 to about 1.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       57 . The composition of  claim 45 , wherein the aluminum ion complexing agent has a concentration of from about 0.01 to about 2.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       58 . The composition of  claim 45 , comprising corrosion inhibitor, wherein the corrosion inhibitor has a concentration of from about 0.01 to about 1.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       59 . The composition of  claim 49 , comprising ammonium fluoride, salicylic acid, and boric acid in a molar ratio of about 1.50:1.53:1.0 (ammonium fluoride:salicylic acid:boric acid).  
   
   
       60 . The composition of  claim 59 , wherein ammonium fluoride has a concentration of from about 0.2 to about 2.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       61 . The composition of  claim 45 , wherein the aluminum ion complexing agent has a concentration of from about 0.2 to about 4.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       62 . The composition of  claim 45 , comprising corrosion inhibitor, wherein the corrosion inhibitor has a concentration of from about 0.2 to about 2.0 wt. %, based on the total weight of the cleaning composition.  
   
   
       63 . The composition of  claim 49 , comprising ammonium fluoride, salicylic acid, and boric acid in a molar ratio of about 1.10:1.0:0.73 (ammonium fluoride:salicylic acid:boric acid).  
   
   
       64 . A method of removing aluminum/SiN/Si post-etch residue from a substrate having same thereon, said method comprising contacting the post-etch residue with a cleaning composition comprising SCCO2, alcohol, fluorine source, an aluminum ion complexing agent and, optionally, corrosion inhibitor, for sufficient time and under sufficient contacting conditions to remove the aluminum/SiN/Si post-etch residue from the substrate.