Composition and method for polishing aluminum semiconductor substrates

Abstract

The invention provides a chemical-mechanical polishing composition comprising coated α-alumina particles, an organic carboxylic acid, and water. The invention also provides a chemical-mechanical polishing composition comprising an abrasive having a negative zeta potential in the polishing composition, an organic carboxylic acid, at least one alkyls disulfonate surfactant, and water, wherein the polishing composition does not further comprise a heterocyclic compound. The abrasive is colloidally stable in the polishing composition. The invention further provides methods of polishing a substrate with the aforesaid polishing compositions.

1 . A chemical-mechanical polishing composition comprising:
 (a) α-alumina particles coated with a copolymer consisting essentially of at least one sulfonate monomer and at least one acrylate monomer,   (b) an organic carboxylic acid, and   (c) water,   
       wherein the polishing composition has a pH of about 1 to about 6, and wherein the abrasive is colloidally stable in the polishing composition. 
     
     
         2 . The composition of  claim 1 , wherein the copolymer comprises about 50 mole % to about 90 mole % of the acrylate monomer and about 10 mole % to about 50 mole % of the sulfonate monomer. 
     
     
         3 . The composition of  claim 1 , wherein the composition further comprises an agent that oxidizes a metal. 
     
     
         4 . The composition of  claim 1 , wherein the composition further comprises a surfactant. 
     
     
         5 . The composition of  claim 4 , wherein the surfactant is an alkyldiphenyloxide disulfonate surfactant. 
     
     
         6 . A chemical-mechanical polishing composition comprising:
 (a) an abrasive, wherein the abrasive comprises particles having a negative zeta potential in the polishing composition,   (b) organic carboxylic acid,   (c) at least one alkyldiphenyloxide disulfonate surfactant, and   (d) water,   
       wherein the polishing composition has a pH of about 1 to about 6, wherein the abrasive is colloidally stable in the polishing composition, and wherein the polishing composition does not comprise a heterocyclic compound. 
     
     
         7 . The composition of  claim 6 , wherein the abrasive is unmodified wet process silica or wet process silica modified with anionic functional groups. 
     
     
         8 . The composition of  claim 6 , wherein the abrasive comprises α-alumina particles coated with a copolymer consisting essentially of at least one sulfonate monomer and at least one acrylate monomer. 
     
     
         9 . The composition of  claim 6 , wherein the complexing agent for aluminum comprises an organic carboxylic acid. 
     
     
         10 . The composition of  claim 9 , wherein the organic carboxylic acid is selected from the group consisting of malonic acid, phthalic acid, lactic acid, tartaric acid, gluconic acid, citric acid, malic acid, glycolic acid, maleic acid, and combinations thereof. 
     
     
         11 . The composition of  claim 6 , wherein the polishing composition further comprises an agent that oxidizes aluminum.