Polishing composition containing ceria abrasive
The invention provides a chemical-mechanical polishing composition including first abrasive particles, wherein the first abrasive particles are wet-process ceria particles, have a median particle size of about 40 nm to about 100 nm, are present in the polishing composition at a concentration of about 0.005 wt. % to about 2 wt. %, and have a particle size distribution of at least about 300 nm, a functionalized heterocycle, a pH-adjusting agent, and an aqueous carrier, and wherein the pH of the polishing composition is about 1 to about 6. The invention also provides a method of polishing a substrate, especially a substrate comprising a silicon oxide layer, with the polishing composition.
1. A chemical-mechanical polishing composition comprising:
(a) first abrasive particles, wherein the first abrasive particles are wet-process ceria particles, have a median particle size of about 40 nm to about 100 nm, are present in the polishing composition at a concentration of about 0.005 wt. % to about 2 wt. %, and have a particle size distribution of at least about 300 nm, wherein the first abrasive particles have a surface that comprises tridentate hydroxyl groups, and wherein the first abrasive particles have a surface coverage of tridentate hydroxyl groups that is about 2.0×10 −5 moles/m 2 or more,
(b) a functionalized heterocycle selected from a functionalized nitrogen-containing heterocycle, a functionalized sulfur-containing heterocycle, a naphthoic acid, and combinations thereof, wherein the functionalized heterocycle is present in the polishing composition at a concentration of about 100 ppm to about 1500 ppm,
(c) a pH-adjusting agent, and
(d) an aqueous carrier,
wherein the pH of the polishing composition is about 1 to about 6.
2. The chemical-mechanical polishing composition of claim 1 , wherein a Raman spectrum of the first abrasive particles comprises a peak at about 458 cm −1 and a peak at about 583 cm −1 , and wherein the ratio of the intensity of the peak at about 458 cm −1 to the intensity of the peak at about 583 cm −1 is about 100 or less.
3. The chemical-mechanical polishing composition of claim 1 , wherein the first abrasive particles are present in the polishing composition at a concentration of about 0.1 wt. % to about 0.5 wt. %.
4. The chemical-mechanical polishing composition of claim 1 , wherein the functionalized heterocycle comprises a functionalized nitrogen-containing heterocycle selected from picolinic acid, quinaldic acid, and combinations thereof.
5. The chemical-mechanical polishing composition of claim 1 , wherein the pH-adjusting agent is selected from an alkyl amine, an alcohol amine, a quaternary amine hydroxide, ammonia, and combinations thereof.
6. The chemical-mechanical polishing composition of claim 5 , wherein the pH-adjusting agent is triethanolamine.
7. The chemical-mechanical polishing composition of claim 1 , wherein the pH of the polishing composition is about 3.5 to about 5.
8. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition further comprises an additive selected from
an anionic copolymer of a carboxylic acid monomer, a sulfonated monomer, or a phosphonated monomer, and an acrylate, a polyvinylpyrrolidone, or a polyvinylalcohol,
a nonionic polymer, wherein the nonionic polymer is polyvinylpyrrolidone or polyethylene glycol,
a silane, wherein the silane is an amino silane, an ureido silane, or a glycidyl silane,
an N-oxide of a functionalized pyridine,
a starch,
a cyclodextrin, and
combinations thereof,
wherein the additive is present in the chemical-mechanical polishing composition at a concentration of about 25 ppm to about 500 ppm.
9. The chemical-mechanical polishing composition of claim 8 , wherein the additive is selected from a copolymer of 2-hydroxyethylmethacrylic acid and methacrylic acid, polyvinylpyrrolidone, aminopropylsilanetriol, picolinic acid N-oxide, starch, alpha-cyclodextrin, beta-cyclodextrin, and combinations thereof.
10. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition further comprises:
a cationic polymer, wherein the cationic polymer is a quaternary amine, and wherein the cationic polymer is present in the polishing composition at a concentration of about 1 ppm to about 250 ppm, and
a carboxylic acid, wherein the pKa of the carboxylic acid is about 1 to about 6, and wherein the carboxylic acid is present in the polishing composition at a concentration of about 25 ppm to about 500 ppm,
wherein the pH of the polishing composition is within about 2 units of the pKa of the carboxylic acid.
11. The chemical-mechanical polishing composition of claim 10 , wherein the cationic polymer is poly(vinylimidazolium).
12. The chemical-mechanical polishing composition of claim 10 , wherein the pKa of the carboxylic acid is about 3.5 to about 5.
13. The chemical-mechanical polishing composition of claim 10 , wherein the carboxylic acid is acetic acid.
14. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition further comprises a cationic polymer selected from a cationic polyvinyl alcohol and a cationic cellulose, and wherein the cationic polymer is present in the polishing composition at a concentration of about 1 ppm to about 250 ppm.
15. A method of polishing a substrate comprising:
(i) providing a substrate;
(ii) providing a polishing pad;
(iii) providing the chemical-mechanical polishing composition of claim 1 ;
(iv) contacting the substrate with the polishing pad and the chemical-mechanical polishing composition; and
(v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of the substrate to polish the substrate.