Chemical mechanical polishing compositions for copper and associated materials and method of using same

Abstract

A CMP composition containing a rheology agent, e.g., in combination with oxidizing agent, chelating agent, inhibiting agent, abrasive and solvent. Such CMP composition advantageously increases the materials selectivity in the CMP process and is useful for polishing surfaces of copper elements on semiconductor substrates, without the occurrence of dishing or other adverse planarization deficiencies in the polished copper.

1 .- 39 . (canceled) 
   
   
       40 . A method of planarizing a wafer substrate having copper films deposited thereon, said method comprising contacting copper with a composition to remove the copper and expose an underlying liner layer, said composition comprising the following composition ranges by weight, based on the total weight of the composition: 
     
       
         
               
               
               
               
             
                   
                   
               
                   
                 oxidizing agent 
                 0.01 to less than 30 
                 wt. % 
               
                   
                 passivating agent 
                 0.01 to 10 
                 wt. % 
               
                   
                 chelating agent 
                 0.1 to 25 
                 wt. % and 
               
                   
                 abrasive 
                 0 to 30 
                 wt. %, 
               
                   
                 rheology agent 
                 0.01 to 5 
                 wt. % 
               
                   
                   
               
           
              
             
             
              
              
              
              
              
              
             
          
         
       
     
     wherein the rheology agent is effective at maintaining the desired viscosity and/or shear rate of the composition while in contact with the substrate. 
   
   
       41 . The method of  claim 40 , wherein the composition has viscosity between 1.5 cSt and 50 cSt at 25° C. 
   
   
       42 . The method of  claim 40 , wherein viscosity decreases as shear rate increases. 
   
   
       43 . The method of  claim 40 , wherein said rheology agent is selected from the group consisting of: Water Soluble Polymers (WSPs) and cross-linked acrylic acid based polymers. 
   
   
       44 . The method of  claim 40 , wherein said rheology agent is selected from the group consisting of: modified cellulose derivatives, cellulose ethers, starch derivatives, pectin derivatives, polyacylamides; and aqueous dispersions thereof. 
   
   
       45 . The method of  claim 40 , wherein said rheology agent is selected from the group consisting of: hydroxypropylcellulose, hydroxyethylcellulose, other cellulose ethers and carboxymethylcellulose. 
   
   
       46 . The method of  claim 40 , wherein said rheology agent comprises hydroxypropylcellulose. 
   
   
       47 . The method of  claim 40 , wherein said oxidizing agent is selected from the group consisting of: hydrogen peroxide (H 2 O 2 ), ferric nitrate (Fe(NO 3 ) 3 ), potassium iodate (KIO 3 ), potassium permanganate (KMnO 4 ), nitric acid (HNO 3 ), ammonium chlorite (NH 4 ClO 2 ), ammonium chlorate (NH 4 ClO 3 ), ammonium iodate (NH 4 BO 3 ), ammonium perborate (NH 4 BO 3 ), ammonium perchlorate (NH 4 ClO 4 ), ammonium periodate (NH 4 BO 3 ), ammonium persulfate ((NH 4 ) 2 S 2 O 8 ), tetramethylammonium chlorite ((N(CH 3 ) 4 )ClO 2 ), tetramethylammonium chlorate ((N(CH 3 ) 4 )ClO 3 ), tetramethylammonium iodate ((N(CH 3 ) 4 )IO 3 ), tetramethylammonium perborate ((N(CH 3 ) 4 )BO 3 ), tetramethylammonium perchlorate ((N(CH 3 ) 4 )ClO 4 ), tetramethylammonium periodate ((N(CH 3 ) 4 )IO 4 ), tetramethylammonium persulfate ((N(CH 3 ) 4 )S 2 O 8 ), urea hydrogen peroxide ((CO(NH 2 ) 2 )H 2 O 2 ), 4-methylmorpholine N-oxide (C 5 H 11 NO 2 ) and pyridine-N-oxide (C 5 H 5 NO). 
   
   
       48 . The method of  claim 40 , wherein said oxidizing agent comprises hydrogen peroxide. 
   
   
       49 . The method of  claim 40 , wherein said chelating agent is selected from the group consisting of: phosphoric acid, glycine, alanine, citric acid, acetic acid, maleic acid, oxalic acid, malonic acid, succinic acid, nitrilotriacetic acid, iminodiacetic acid, ethylenediamine, and EDTA. 
   
   
       50 . The method of  claim 40 , wherein said chelating agent comprises glycine. 
   
   
       51 . The method of  claim 40 , wherein said corrosion inhibitor is selected from the group consisting of: imidazole, aminotetrazole, benzotriazole, benzimidazole, oxalic acid, malonic acid, succinic acid, nitrilotriacetic acids, iminodiacetic acids, and derivatives and combinations thereof. 
   
   
       52 . The method of  claim 40 , wherein said corrosion inhibitor comprises 5-aminotetrazole (ATA) or 5-aminotetrazole monohydrate. 
   
   
       53 . The method of  claim 40 , wherein the composition has a pH that is between about 2 and 11. 
   
   
       54 . The method of  claim 40 , wherein said solvent is selected from the group consisting of water, organic solvent and combinations thereof. 
   
   
       55 . The method of  claim 40 , wherein said solvent is selected from the group consisting of: water, methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, glycerin, and combinations thereof. 
   
   
       56 . The method of  claim 40 , wherein the rheology agent causes abrasive particles to become constrained in a flow plane between a wafer substrate surface and a polishing pad. 
   
   
       57 . The method of  claim 40 , wherein shear rate is greater at elevated wafer substrate topography than at via and line trenches. 
   
   
       58 . The method of  claim 40 , wherein the CMP composition is formulated as a two-part composition in which the first part comprises all components of the composition except the oxidizing agent, and the second part comprises the oxidizing agent. 
   
   
       59 . The method of  claim 40 , wherein the removal selectivities of copper and liner materials is altered by reducing the concentration of the oxidizing agent in situ.