Colloidal silica chemical-mechanical polishing concentrate

1. A chemical-mechanical polishing concentrate comprising:

a water based liquid carrier;

at least 10 weight percent colloidal silica abrasive particles dispersed in the liquid carrier;

an aminosilane compound or a phosphonium silane compound incorporated in the colloidal silica abrasive particles internal to an outer surface thereof; and

a pH in a range from about 1.5 to about 7.

2. The concentrate of claim 1 , comprising at least 12 weight percent of the colloidal silica abrasive particles.

3. The concentrate of claim 1 , comprising at least 15 weight percent of the colloidal silica abrasive particles.

4. The concentrate of claim 1 , wherein the colloidal silica abrasive particles have a permanent positive charge of at least 10 mV.

5. The concentrate of claim 1 , wherein the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV.

6. The concentrate of claim 1 , having a pH in a range from about 3.5 to about 6.

7. The concentrate of claim 1 , further comprising a buffering agent having a pKa in a range from about 3.5 to about 5.5.

8. The concentrate of claim 1 , wherein a molar ratio of the aminosilane compound to silica in the colloidal silica abrasive particles is less than 10 percent.

9. The concentrate of claim 8 , wherein the molar ratio is less than 5 percent.

10. The concentrate of claim 1 , wherein the colloidal silica abrasive particles have a mean particle size in a range from about 30 to about 70 nm.

11. The concentrate of claim 1 , wherein the colloidal silica abrasive particles have a mean particle size in a range from about 40 to about 60 nm.

12. The concentrate of claim 1 , wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.

13. The concentrate of claim 1 , wherein 50 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles and 20 percent or more of the colloidal silica abrasive particles are monomers or dimers.

14. The concentrate of claim 1 , wherein the aminosilane compound comprises a propyl group, primary amine, or quaternary amine.

15. The concentrate of claim 1 , wherein the aminosilane compound comprises bis(2-hydroxyethyl)-3-aminopropyl trialkoxysilane, diethylaminomethyltrialkoxysilane,N,N-diethyl-3-aminopropyl)trialkoxysilane), 3-(N-styrylmethyl-2-aminoethylaminopropyl trialkoxysilane, aminopropyl trialkoxysilane, (2-N-benzylaminoethyl)-3-aminopropyl trialkoxysilane), trialkoxysilyl propyl-N,N,N-trimethyl ammonium, N-(trialkoxysilylethyl)benzyl-N,N,N-trimethyl ammonium, (bis(methyldialkoxysilylpropyl)-N-methyl amine, bis(trialkoxysilylpropyl)urea, bis(3-(trialkoxysilyl)propyl)-ethylenediamine, bis(trialkoxysilylpropyl)amine, bis(trialkoxysilylpropyl)amine, 3-aminopropyltrialkoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldialkoxysilane, N-(2-aminoethyl)-3-aminopropyltrialkoxysilane, 3-aminopropylmethyldialkoxysilane, 3-aminopropyltrialkoxysilane, (N -trialkoxysilylpropyl)polyethyleneimine, trialkoxysilylpropyldiethylenetriamine, N-phenyl-3-aminopropyltrialkoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrialkoxysilane, 4-aminobutyltrialkoxysilane, or a mixture thereof.

16. The concentrate of claim 1 , having an electrical conductivity of less than about 1000 μS/cm.

17. The concentrate of claim 1 , having an electrical conductivity of less than about 500 μS/cm.

18. The concentrate of claim 1 , having a total metals impurity level of less than about 10 parts per million, wherein the total metals include sodium, aluminum, calcium, magnesium, and transition metals.

19. The concentrate of claim 1 , wherein the colloidal silica has a density of greater than 1.90 g/cm 3 .

20. The concentrate of claim 1 , wherein a mean particle size does not increase more than about 5 nm when subject to accelerating aging at 45 degrees C. for 1 week.

21. The concentrate of claim 1 , wherein:

the colloidal silica abrasive particles have a permanent positive charge of at least 10 mV;

the concentrate has a pH in a range from about 3.5 to about 6;

the colloidal silica abrasive particles have a mean particle size in a range from about 30 to about 70 nm; and

30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.

22. The concentrate of claim 1 , wherein:

the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV;

the concentrate has an electrical conductivity of less than about 1000 μS/cm;

the concentrate has a pH in a range from about 3.5 to about 6; and

a molar ratio of the aminosilane compound to silica in the colloidal silica abrasive particles is less than 10 percent.

23. The concentrate of claim 1 , wherein:

the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV;

the concentrate has a pH in a range from about 3.5 to about 6;

the concentrate further includes a buffering agent having a pKa in a range from about 3.5 to about 5.5;

30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles;

a molar ratio of the aminosilane compound to silica in the colloidal silica abrasive particles is less than 10 percent; and

the aminosilane compound comprises a propyl group.

24. A method of chemical-mechanical polishing a substrate including a silicon oxygen material, the method comprising:

(a) diluting the chemical-mechanical polishing concentrate of claim 1 to obtain a polishing composition by adding at least 3 parts water to 1 part of the chemical-mechanical polishing concentrate,

(b) contacting the substrate with the polishing composition;

(c) moving the polishing composition relative to the substrate; and

(d) abrading the substrate to remove a portion of the silicon oxygen containing material from the substrate and thereby polish the substrate.

25. The method of claim 24 , wherein the chemical-mechanical polishing concentrate comprises at least 12 weight percent of the colloidal silica abrasive particles and (a) comprises adding at least 4 parts water to 1 part of the chemical-mechanical polishing concentrate.

26. The method of claim 24 , wherein the chemical-mechanical polishing concentrate comprises at least 15 weight percent of the colloidal silica abrasive particles and (a) comprises adding at least 5 parts water to 1 part of the chemical-mechanical polishing concentrate.

27. The method of claim 24 , wherein:

the polishing composition comprises less than 3 percent by weight of the colloidal silica abrasive particles;

an average removal rate of the silicon oxygen material in (c) is greater than 3000 Å/min at a downforce of 5 psi or less; and

an average removal rate of the silicon oxygen material in (c) is greater than 2000 Å/min at a downforce of 4 psi or less.

28. The method of claim 24 , wherein:

the polishing composition comprises less than 2.5 percent by weight of the colloidal silica abrasive particles;

an average removal rate of the silicon oxygen material in (c) is greater than 3000 Å/min at a downforce of 5 psi or less; and

an average removal rate of the silicon oxygen material in (c) is greater than 2000 Å/min at a downforce of 4 psi or less.

29. The method of claim 24 , wherein:

the chemical-mechanical polishing concentrate comprises at least 12 weight percent of the colloidal silica abrasive particles and (a) comprises adding at least 5 parts water to 1 part of the chemical-mechanical polishing concentrate such that the polishing composition comprises 2.0 weight percent or less of the colloidal silica abrasive particles; and

an average removal rate of the silicon oxygen material in (c) is greater than 3000 Å/min at a downforce of 5 psi or less; and

an average removal rate of the silicon oxygen material in (c) is greater than 2000 Å/min at a downforce of 4 psi or less.