Friction reducing aid for CMP

Abstract

The invention provides a chemical-mechanical polishing system for polishing a substrate comprising a polishing component, a water-soluble silicate compound, an oxidizing agent, and water, wherein the pH of the polishing system is about 8 to about 12. The invention further provides a method of chemically-mechanically polishing a substrate with the aforementioned polishing system. The polishing system provides for reduced friction during polishing of substrates.

1 . A chemical-mechanical polishing system for polishing a substrate comprising: 
 (a) a polishing component selected from the group consisting of a polishing pad, an abrasive, and a combination thereof,    (b) a water-soluble silicate compound in an amount sufficient to provide about 0.1 wt. % or more of SiO 2 ,    (c) an oxidizing agent that oxidizes at least part of a substrate, and    (d) water,    wherein the pH of the polishing system is about 8 to about 12, and wherein the water-soluble silicate compound is present in aqueous solution in the polishing system.    
   
   
       2 . The polishing system of  claim 1 , wherein the water-soluble silicate compound is selected from the group consisting of potassium silicate, sodium silicate, potassium metasilicate, and sodium metasilicate.  
   
   
       3 . The polishing system of  claim 2 , wherein the water-soluble silicate compound is potassium silicate.  
   
   
       4 . The polishing system of  claim 3 , wherein the potassium silicate is present in an amount sufficient to provide about 0.25 wt. % or more of SiO 2 .  
   
   
       5 . The polishing system of  claim 3 , wherein the potassium silicate has a SiO 2 :K 2 O molar ratio of about 2.8 to about 3.9.  
   
   
       6 . The polishing system of  claim 5 , wherein the potassium silicate has a SiO 2 :K 2 O molar ratio of about 3 to about 3.6.  
   
   
       7 . The polishing system of  claim 1 , wherein the oxidizing agent is selected from the group consisting of hydrogen peroxide, iodates, permanganates, persulfates, hydrogen peroxymonosulfate sulfates, molybdates, ferric nitrate, nitrates, quinones, and combinations thereof.  
   
   
       8 . The polishing system of  claim 1 , wherein the polishing system further comprises an abrasive wherein the abrasive is suspended in the water.  
   
   
       9 . The polishing system of  claim 8 , wherein the abrasive is selected from the group consisting of alumina, ceria, silica, zirconia, and combinations thereof.  
   
   
       10 . The polishing system of  claim 1 , wherein the polishing system comprises a polishing pad and an abrasive wherein the abrasive is fixed to the polishing pad.  
   
   
       11 . The polishing system of  claim 1 , wherein the water-soluble silicate compound is present in an amount of about 0.5 wt. % or more.  
   
   
       12 . The polishing system of  claim 1 , wherein the pH is about 9 to about 11.  
   
   
       13 . A method of chemically-mechanically polishing a substrate, which method comprises: 
 (i) contacting a substrate with a chemical-mechanical polishing system comprising: 
 (a) a polishing component selected from the group consisting of a polishing pad, an abrasive, and a combination thereof,  
 (b) a water-soluble silicate compound in an amount sufficient to provide about 0.1 wt. % or more of SiO 2 ,  
 (c) an oxidizing agent that oxidizes at least part of a substrate, and  
 (d) water, wherein the pH of the polishing system is about 8 to about 12, and wherein the water-soluble silicate compound is present in aqueous solution in the polishing system, and  
   (ii) abrading at least a portion of the substrate to polish the substrate.    
   
   
       14 . The method of  claim 13 , wherein the water-soluble silicate compound is selected from the group consisting of potassium silicate, sodium silicate, potassium metasilicate, and sodium metasilicate.  
   
   
       15 . The method of  claim 14 , wherein the water-soluble silicate compound is potassium silicate.  
   
   
       16 . The method of  claim 15 , wherein the potassium silicate is present in an amount sufficient to provide about 0.25 wt. % or more of SiO 2 .  
   
   
       17 . The method of  claim 15 , wherein the potassium silicate has a SiO 2 :K 2 O molar ratio of about 2.8 to about 3.9.  
   
   
       18 . The method of  claim 17 , wherein the potassium silicate has a SiO 2 :K 2 O molar ratio of about 3 to about 3.6.  
   
   
       19 . The method of  claim 13 , wherein the oxidizing agent is selected from the group consisting of hydrogen peroxide, iodates, permanganates, persulfates, hydrogen peroxymonosulfate sulfates, molybdates, ferric nitrate, nitrates, quinones, and combinations thereof.  
   
   
       20 . The method of  claim 13 , wherein the polishing system further comprises an abrasive wherein the abrasive is suspended in the water.  
   
   
       21 . The method of  claim 20 , wherein the abrasive is selected from the group consisting of alumina, ceria, silica, zirconia, and combinations thereof.  
   
   
       22 . The method of  claim 13 , wherein the polishing system comprises a polishing pad and an abrasive wherein the abrasive is fixed to the polishing pad.  
   
   
       23 . The method of  claim 13 , wherein the water-soluble silicate compound is present in an amount of about 0.5 wt. % or more.  
   
   
       24 . The method of  claim 13 , wherein the pH is about 9 to about 11.  
   
   
       25 . The method of  claim 13 , wherein the substrate comprises a metal layer.  
   
   
       26 . The method of  claim 25 , wherein the metal layer comprises tantalum.  
   
   
       27 . The method of  claim 26 , wherein the metal layer further comprises copper.  
   
   
       28 . The method of  claim 13 , wherein the substrate comprises a dielectric layer which has a dielectric constant of about 3.5 or lower.  
   
   
       29 . The method of  claim 28 , wherein the dielectric layer is an organically modified silicon glass.  
   
   
       30 . The method of  claim 28 , wherein the dielectric layer is carbon-doped silicon dioxide.  
   
   
       31 . The method of  claim 28 , wherein the substrate further comprises a metal layer.  
   
   
       32 . The method of  claim 31 , wherein the metal layer comprises tantalum.  
   
   
       33 . The method of  claim 32 , wherein the metal layer further comprises copper.