Low pH barrier slurry based on titanium dioxide

1. A method of chemically-mechanically polishing a substrate, which method comprises:

(i) contacting a substrate comprising at least one layer of ruthenium with a polishing pad and a chemical-mechanical polishing composition comprising:

(a) an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å, and

(b) water,

(ii) moving the polishing pad and the polishing composition relative to the substrate, and

(iii) abrading at least a portion of the ruthenium to polish the substrate.

2. The method of claim 1 , wherein the polishing composition comprises about 0.001 wt. % to about 1 wt. % of the abrasive.

3. The method of claim 1 , wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.

4. The method of claim 1 , wherein the particles have an average particle size of about 50 nm to about 100 nm.

5. The method of claim 1 , wherein the polishing composition further comprises a cationic copolymer comprising (A) cationic repeating units comprising quaternary amino groups and (B) nonionic repeating units.

6. The method of claim 1 , wherein the substrate further comprises at least one layer of silicon dioxide, and at least a portion of the silicon dioxide is abraded to polish the substrate.

7. The method of claim 6 , wherein a selectivity for polishing ruthenium as compared to silicon dioxide is about 0.5 to about 2.

8. The method of claim 1 , wherein the substrate further comprises at least one layer of copper, and at least a portion of the copper is abraded to polish the substrate.

9. The method of claim 1 , wherein the polishing composition further comprises a peroxide compound.

10. The method of claim 9 , wherein the peroxide compound is hydrogen peroxide.

11. The method of claim 9 , wherein the substrate further comprises at least one layer of silicon dioxide, and at least a portion of the silicon dioxide is abraded to polish the substrate.

12. The method of claim 11 , wherein a selectivity for polishing ruthenium as compared to silicon dioxide is about 2 or more.

13. The method of claim 9 , wherein the polishing composition further comprises a cationic copolymer comprising (A) cationic repeating units comprising quaternary amino groups and (B) nonionic repeating units.

14. The method of claim 13 , wherein a selectivity for polishing ruthenium as compared to silicon dioxide is about 2 or less.

15. The method of claim 9 , wherein the substrate further comprises at least one layer of copper, and at least a portion of the copper is abraded to polish the substrate.

16. The method of claim 1 , wherein the chemical-mechanical polishing composition consists essentially of:

(a) about 0.001 wt. % to about 1 wt. % of an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å, and

(b) water,

wherein the particles have an average particle size of about 50 nm to about 100 nm, and wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.

17. The method of claim 16 , wherein the substrate further comprises at least one layer of copper, and at least a portion of the copper is abraded to polish the substrate.

18. The method of claim 1 , wherein the chemical-mechanical polishing composition consists essentially of:

(a) about 0.001 wt. % to about 1 wt. % of an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å,

(b) a peroxide compound, and

(c) water,

wherein the particles have an average particle size of about 50 nm to about 100 nm, and wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.

19. The method of claim 18 , wherein the substrate further comprises at least one layer of copper, and at least a portion of the copper is abraded to polish the substrate.

20. The method of claim 1 , wherein the chemical-mechanical polishing composition consists essentially of:

(a) about 0.001 wt. % to about 1 wt. % of an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å,

(b) a peroxide compound,

(c) a cationic copolymer comprising (A) cationic repeating units comprising quaternary amino groups and (B) nonionic repeating units, and

(d) water,

wherein the particles have an average particle size of about 50 nm to about 100 nm, and wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.

21. The method of claim 20 , wherein the substrate further comprises at least one layer of copper, and at least a portion of the copper is abraded to polish the substrate.

22. The method of claim 1 , wherein the chemical-mechanical polishing composition consists essentially of:

(a) about 0.001 wt. % to about 1 wt. % of an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å,

(b) a peroxide compound,

(c) a corrosion inhibitor, and

(d) water,

wherein the particles have an average particle size of about 50 nm to about 100 nm, and wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.

23. The method of claim 1 , wherein the chemical-mechanical polishing composition consists essentially of:

(a) about 0.001 wt. % to about 1 wt. % of an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å,

(b) a peroxide compound,

(c) a cationic copolymer comprising (A) cationic repeating units comprising quaternary amino groups and (B) nonionic repeating units,

(d) a corrosion inhibitor, and

(e) water,

wherein the particles have an average particle size of about 50 nm to about 100 nm, and wherein the pH of the water and any components dissolved or suspended therein is about 2 to about 6.