Colloidal silica chemical-mechanical polishing composition
A chemical-mechanical polishing composition includes colloidal silica abrasive particles dispersed in a liquid carrier having a pH in a range from about 1.5 to about 7. The colloidal silica abrasive particles include an aminosilane compound or a phosphonium silane compound incorporated therein. The composition may be used to polish a substrate including a silicon oxygen material such as TEOS.
1. A chemical mechanical polishing composition comprising:
a water based liquid carrier;
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 composition of claim 1 , wherein the colloidal silica abrasive particles have a positive charge of at least 13 mV.
3. The composition of claim 1 , wherein the colloidal silica abrasive particles have a positive charge of at least 20 mV.
4. The composition of claim 1 , wherein the colloidal silica abrasive particles have a positive charge of at least 15 mV and less than 35 mV.
5. The composition of claim 1 , having a pH in a range from about 3.5 to about 6.
6. The composition of claim 1 , further comprising a buffering agent having a pKa in a range from about 3.5 to about 5.5.
7. The composition of claim 1 , wherein the colloidal silica abrasive particles have a mean particle size in a range from about 30 to about 70 nm.
8. The composition of claim 1 , wherein the colloidal silica abrasive particles have a mean particle size in a range from about 40 to about 60 nm.
9. The composition of claim 1 , comprising from about 0.5 to about 4 weight percent of the colloidal silica abrasive particles.
10. The composition of claim 1 , comprising less than about 3 weight percent of the colloidal silica abrasive particles.
11. The composition of claim 1 , wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.
12. The composition 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.
13. The composition of claim 1 , wherein the colloidal silica abrasive particles include primary particles and 95 percent or more of the primary particles have a primary particle size in a range from 15 to 35 nm.
14. The composition of claim 1 , wherein a molar ratio of the aminosilane compound to silica in the colloidal silica abrasive particles is less than 10 percent.
15. The composition of claim 14 , wherein the molar ratio is less than 5 percent.
16. The composition of claim 1 , further comprising an alkali catalyst incorporated in the colloidal silica abrasive particles internal to the outer surface thereof.
17. The composition of claim 16 , wherein the alkali catalyst has from 1 to 6 carbon atoms.
18. The composition of claim 16 , wherein the alkali catalyst is tetramethylammonium hydroxide or ethyloxypropylamine.
19. The composition of claim 1 , wherein the aminosilane compound comprises a propyl group, primary amine, or quaternary amine.
20. The composition 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.
21. The composition of claim 1 , wherein the colloidal silica abrasive particles have a core-shell structure in which an outer shell is disposed over an inner core, the aminosilane compound or the phosphonium silane compound being incorporated in the outer shell.
22. The composition of claim 21 , wherein the outer shell has a thickness of at least 1 nm.
23. The composition of claim 1 , having an electrical conductivity of less than about 300 μS/cm.
24. The composition of claim 1 , wherein the colloidal silica has a density of greater than 1.90 g/cm 3 .
25. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a positive charge of at least 13 mV;
the composition has a pH in a range from about 3.5 to about 6;
30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles; and
the composition includes from about 0.5 to about 4 weight percent of the colloidal silica abrasive particles.
26. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a positive charge of at least 13 mV;
the composition further includes a buffering agent having a pKa in a range from about 3.5 to about 5.5;
the colloidal silica abrasive particles have a mean particle size in a range from about 30 to about 70 nm;
the composition includes less than about 3 weight percent of the colloidal silica abrasive particles; and
the aminosilane compound comprises a propyl group.
27. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a positive charge of at least 13 mV;
the composition 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;
the composition includes less than about 3 weight percent of the colloidal silica abrasive particles;
the colloidal silica has a density of greater than 1.90 g/cm 3 ; and
the aminosilane compound comprises a propyl group.
28. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a positive charge of at least 15 mV;
the composition has a pH in a range from about 3.5 to about 6; and
the composition has an electrical conductivity of less than about 300 μS/cm.
29. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a positive charge of at least 15 mV;
30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles; and
the colloidal silica abrasive particles include primary particles and 95 percent or more of the primary particles have a primary particle size in a range from 15 to 35 nm.
30. The composition of claim 1 , further comprising a silicon nitrogen polishing accelerator including a polycarboxylic acid, a poly phosphonic acid, or a mixture thereof.
31. The composition of claim 30 , wherein the polycarboxylic acid comprises oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, sulfosuccinic acid, or a mixture thereof.
32. The composition of claim 30 , wherein the poly phosphonic acid comprises a diphosphonic acid compound or a methylene phosphonic acid compound.
33. The composition of claim 1 , further comprising a silicon nitrogen polishing inhibitor having a ring and a nitrogen atom in or bonded to the ring.
34. The composition of claim 33 , wherein the inhibitor further comprises a hydroxy group bonded to the ring.
35. A method of chemical mechanical polishing a substrate including a silicon oxygen material, the method comprising:
(a) contacting the substrate with the chemical mechanical polishing composition of claim 1 ;
(b) moving the polishing composition relative to the substrate; and
(c) abrading the substrate to remove a portion of the silicon oxygen containing material from the substrate and thereby polish the substrate.
36. The method of claim 35 , wherein:
the polishing composition has a pH of less than 6 and comprises less than 4 percent by weight 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.
37. The method of claim 35 , wherein:
the polishing composition has a pH of less than 6 and comprises less than 2 percent by weight 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.
38. The method of claim 35 , wherein:
the polishing composition has a pH of less than 6 and comprises less than 3 percent by weight of the colloidal silica abrasive particles; 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.
39. The method of claim 35 , wherein:
the polishing composition has a pH of less than 6 and comprises less than 2.0 percent by weight of the colloidal silica abrasive particles; 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.
40. The method of claim 35 , wherein:
the polishing composition has a pH in a range from about 3.5 to about 5.5 and comprises less than 2.5 percent by weight of the colloidal silica abrasive particles; and
a removal rate of the silicon oxygen material in (c) is greater than 3000 Å/min at a downforce of 5 psi or less.
41. The method of claim 35 , wherein:
the polishing composition has a pH in a range from about 3.5 to about 5.5 and comprises less than 2.5 percent by weight of the colloidal silica abrasive particles; and
a removal rate of the silicon oxygen material in (c) is greater than 2000 Å/min at a down force of 4 psi or less and a removal rate of a silicon nitride material is less than 300 Å/min at a downforce of 3 psi or less.
42. The method of claim 35 , wherein the polishing composition further comprises a silicon nitrogen polishing accelerator and a TEOS:SiN polishing rate selectivity is less than about 10:1.
43. The method of claim 35 , wherein the polishing composition further comprises a silicon nitrogen polishing inhibitor and a TEOS:SiN polishing rate selectivity is greater than about 25:1.
44. The method of claim 35 , wherein:
the polishing composition further comprises a silicon nitrogen polishing accelerator and has a pH in a range from about 3 to about 7; and
a removal rate of the silicon oxygen material in (c) is greater than 2000 Å/min at a down force of 4 psi or less and a removal rate of a silicon nitride material is greater than 200 Å/min at a downforce of 4 psi or less.