Polishing slurry and method of polishing

Abstract

A polishing slurry comprises a metal-oxidizing agent, a metal anticorrosive agent, an oxidized metal dissolving agent and water. The oxidized metal dissolving agent is at least one kind selected from the group consisting of an acid in which the negative value of the logarithm of the dissociation constant Ka (pKa) of a first dissociable acid group is 3.5 or more, an ammonium salt of the acid and an organic acid ester of the acid. The pH of the polishing slurry is within the range of 3 to 4. The concentration of the metal-oxidizing agent is within the range of 0.01 to 3 percent by weight. In the wiring-formation process of the semiconductor device, the conductor used for the barrier layer can be polished at a high polishing rate by using the polishing slurry having the low polishing particle concentration and the low metal anticorrosive agent concentration.

1 . A polishing slurry comprising:
 a metal-oxidizing agent; a metal anticorrosive agent; an oxidized metal dissolving agent; and water,   wherein the oxidized metal dissolving agent is at least one kind selected from the group consisting of an acid in which the negative value of the logarithm of the dissociation constant Ka (pKa) of a first dissociable acid group is 3.5 or more, an ammonium salt of the acid and an organic acid ester of the acid, the pH of the polishing slurry is within the range of 3 to 4, and the concentration of the metal-oxidizing agent is within the range of 0.01 to 3 percent by weight,   wherein the polishing slurry is capable of polishing a barrier layer.   
     
     
         2 . The polishing slurry of  claim 1 , wherein the concentration of the oxidizing agent is within the range of 0.01 to 1.5 percent by weight. 
     
     
         3 . The polishing slurry of  claim 1 , wherein the oxidized metal dissolving agent is an organic acid. 
     
     
         4 . The polishing slurry of  claim 3 , wherein the organic acid is at least one kind selected from the group consisting of lactic acid, succinic acid, adipic acid, glutaric acid, benzoic acid, quinaldic acid, butyric acid and valeric acid. 
     
     
         5 . The polishing slurry of  claim 1 , wherein the metal anticorrosive agent is at least one kind selected from the group consisting of a compound having a triazole skeleton other than benzotriazole, a compound having a pyrimidine skeleton, a compound having an imidazole skeleton, a compound having a guanidine skeleton, a compound having a thiazole skeleton, a compound having a pyrazole skeleton and benzotriazole. 
     
     
         6 . The polishing slurry of  claim 1 , wherein the metal-oxidizing agent is at least one kind selected from the group consisting of hydrogen peroxide, ammonium persulfate, ferric nitrate, nitric acid, potassium periodate, hypochlorous acid and ozone water. 
     
     
         7 . The polishing slurry of  claim 1 , wherein the polishing slurry contains polishing particles. 
     
     
         8 . The polishing slurry of  claim 7 , wherein the polishing particles are at least one kind selected from the group consisting of silica, alumina, ceria, titania, zirconia and germania. 
     
     
         9 . The polishing slurry of  claim 7 , wherein the polishing particles are colloidal silica or colloidal alumina having an average particle diameter of 100 nm or less. 
     
     
         10 . The polishing slurry of  claim 1 , wherein the polishing slurry contains a water-soluble polymer compound. 
     
     
         11 . The polishing slurry of  claim 10 , wherein the water-soluble polymer compound is at least one kind selected from the group consisting of polyacrylic acid and the salt thereof, polymethacrylic acid and the salt thereof, polyacrylamide, polyvinyl alcohol, and polyvinylpyrrolidone. 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled)