Compositions and methods for a barrier removal

Abstract

The present invention provides an aqueous composition useful for polishing a semiconductor wafer, the wafer comprising a tantalum barrier material in the presence of a dielectric and an interconnect metal. The composition comprises an azole compound having a concentration sufficient to accelerate removal of the tantalum barrier material. In addition, the azole compound does not inhibit removal of the interconnect metal. The composition further comprises an abrasive. Also, the composition has a greater selectivity of the tantalum barrier material relative to the dielectric.

1 . An aqueous composition useful for polishing a semiconductor wafer, the wafer comprising a tantalum barrier material in the presence of a dielectric and an interconnect metal, the composition comprising: 
 an azole compound having a concentration sufficient to accelerate removal of the tantalum barrier material, the azole compound not inhibiting removal of the interconnect metal;    an abrasive; and    wherein the composition has a greater selectivity of the tantalum barrier material relative to the dielectric.    
     
     
         2 . The composition of  claim 1  wherein the concentration is 0.05 to 25 weight percent of the azole compound.  
     
     
         3 . The composition of  claim 1  wherein the composition comprises 0.05 to 10 weight percent of the abrasive.  
     
     
         4 . The composition of  claim 1  wherein the composition has a selectivity of the tantalum barrier material relative to a metal of at least 2 to 1 as measured with a microporous polyurethane polishing pad pressure measured normal to a wafer of 20.7 kPa.  
     
     
         5 . The composition of  claim 1  wherein the azole compound is selected from the group comprising: triazole, tetrazole, and a mixture thereof.  
     
     
         6 . The composition of  claim 5  wherein the triazole is selected from the group comprising: 1,2,4-triazole, 3-methyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, 1-amino-1,2,4-triazole, 3-amino-1,2,4-triazole, 5-amino-3-methyl-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 1,2,3-triazole, 1-methyl-1,2,3-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 4,5-dimethyl-1,2,3-triazole, 1-amino-5-n-propyl-1,2,3-triazole, 1-(β-aminoethyl)-1,2,3-triazole, a substituted triazole compound having an electron-donating substituent, and a mixture thereof.  
     
     
         7 . The composition of  claim 5  wherein the tetrazole is selected from the group comprising: 1-methyltetrazole, 2-methyltetrazole, 5-amino-1H-tetrazole, 5-amino-1-methyltetrazole, 1-(β-aminoethyl)tetrazole, a substituted tetrazole compound having an electron-donating substituent, and a mixture thereof.  
     
     
         8 . An aqueous composition useful for polishing tantalum barrier material from a semiconductor wafer, comprising by weight percent 0 to 25 oxidizer, 0 to 6 inhibitor for a nonferrous metal, 0 to 15 complexing agent for the nonferrous metal, 0.05 to 25 azole compound, 0.05 to 12 abrasive, wherein the composition has a selectivity of the tantalum barrier material relative to a dielectric of at least 10 to 1 as measured with a microporous polyurethane polishing pad pressure measured normal to a wafer of 20.7 kPa and the azole compound is selected from the group comprising, 1,2,4-triazole, 3-methyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, 1-amino-1,2,4-triazole, 3-amino-1,2,4-triazole, 5-amino-3-methyl-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 1,2,3-triazole, 1-methyl-1,2,3-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 4,5-dimethyl-1,2,3-triazole, 1-amino-5-n-propyl-1,2,3-triazole, 1-(β-aminoethyl)-1,2,3-triazole, 1-methyltetrazole, 2-methyltetrazole, 5-amino-1H-tetrazole, 5-amino-1-methyltetrazole, 1-(β-aminoethyl)tetrazole, a substituted triazole or tetrazole compound having an electron-donating substituent, and a mixture thereof.  
     
     
         9 . A chemical mechanical planarization method for polishing a semiconductor wafer, the wafer comprising a tantalum barrier material in the presence of a dielectric and an interconnect metal, the method comprising: 
 contacting the wafer with a polishing composition, the polishing composition containing an azole compound and an abrasive, the azole compound having a concentration sufficient to accelerate removal of the tantalum barrier material, the azole compound not inhibiting removal of the interconnect metal; and    polishing the wafer with a polishing pad to remove the tantalum barrier material at a removal rate greater than a removal rate for the dielectric as expressed in angstroms per minute.    
     
     
         10 . The method of  claim 9  wherein the azole compound is selected from the group comprising: 1,2,4-triazole, 3-methyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, 1-amino-1,2,4-triazole, 3-amino-1,2,4-triazole, 5-amino-3-methyl-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 1,2,3-triazole, 1-methyl-1,2,3-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 4,5-dimethyl-1,2,3-triazole, 1-amino-5-n-propyl-1,2,3-triazole, 1-(β-aminoethyl)-1,2,3 -triazole, 1-methyltetrazole, 2-methyltetrazole, 5-amino-1H-tetrazole, 5-amino-1-methyltetrazole, 1-(β-aminoethyl)tetrazole, a substituted triazole or tetrazole compound having an electron-donating substituent, and a mixture thereof.