Slurry and use thereof for polishing

Abstract

A slurry containing abrasive particles, an oxidizing agent having a low static etch rate on at least one acid or salt metal, and having a pH of about 5 to about 11 is especially useful for polishing surfaces, including both metal and silicon dioxide, such as present in microelectronics, at the same or substantially the same polishing rates.

1 . A slurry composition capable of polishing both metal and silicon dioxide at substantially equal rates and comprising silica abrasive particles and an oxidizing agent having a static etch rate on metal of less than 1000 Å per hour; and wherein the pH of the slurry is about 7 to about 9.  
   
   
       2 . The slurry composition of  claim 1  wherein said oxidizing agent is present in the composition in amounts of about 1 g/L to about 100 g/L.  
   
   
       3 . The slurry composition of  claim 1  wherein said silica abrasive particles are present in the composition in amounts of about 0.2 to about 30% by weight.  
   
   
       4 . The slurry composition of  claim 1  wherein said oxidizing agent is selected from the group consisting of potassium iodate, sodium iodate, ammonium cerium nitrate and potassium ferricyanide.  
   
   
       5 . The slurry composition of  claim 1  wherein said oxidizing agent comprises potassium iodate.  
   
   
       6 . The slurry composition of  claim 1  wherein said oxidizing agent comprises ammonium cerium nitrate.  
   
   
       7 . The slurry of  claim 1  wherein said silica abrasive particles have a particle size of about 10 to about 1000 nanometers.  
   
   
       8 . The slurry of  claim 1  wherein said silica is fumed silica or colloidal silica.  
   
   
       9 . The slurry of  claim 1  wherein said abrasive particles include ceria.  
   
   
       10 . The slurry of  claim 1  being an aqueous slurry.  
   
   
       11 . The slurry of  claim 10  which further contains an organic diluent.  
   
   
       12 . The slurry of  claim 11  wherein said organic diluent is selected from the group consisting of propylene carbonate, methanol, ethanol, ethylene glycol, glycerol and mixtures thereof.  
   
   
       13 . The slurry of  claim 1  which contains an organic diluent.  
   
   
       14 . The slurry of  claim 13  wherein said organic diluent is selected from the group consisting of propylene carbonate, methanol, ethanol, ethylene glycol, glycerol and mixtures thereof.  
   
   
       15 . The slurry from  claim 1  which further comprises a surfactant.  
   
   
       16 . The slurry of  claim 1  which further comprises at least one polymer selected from the group consisting of polymer of ethylene oxide, polymer of acrylic acid, polymers of acrylamide, polymers of vinyl alcohol, copolymers thereof and mixtures thereof.  
   
   
       17 . The slurry of  claim 1  which is capable of polishing metal and silicon dioxide at rates of 1:2 to 2:1 using a soft polishing pad.  
   
   
       18 . The slurry of  claim 1  which consists essentially of water, said silica abrasive particles and said oxidizing agent.