Copper barrier chemical-mechanical polishing composition
A chemical-mechanical polishing composition includes colloidal silica abrasive particles having a chemical compound incorporated therein. The chemical compound may include a nitrogen-containing compound such as an aminosilane or a phosphorus-containing compound. Methods for employing such compositions include applying the composition to a semiconductor substrate to remove at least a portion of at least one of a copper, a copper barrier, and a dielectric layer.
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;
an oxidizer; and
at least one of a copper polishing inhibitor and a copper complexing agent.
2. The composition of claim 1 , having a pH in a range from about 3 to about 6.
3. The composition of claim 1 , wherein the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV.
4. 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.
5. The composition of claim 1 , comprising from about 1 to about 10 weight percent of the colloidal silica abrasive particles.
6. The composition of claim 1 , comprising from about 2 to about 6 weight percent of the colloidal silica abrasive particles.
7. The composition of claim 1 , wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.
8. 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.
9. The composition of claim 1 , wherein the aminosilane compound comprises a propyl group, primary amine, or quaternary amine.
10. 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.
11. The composition of claim 1 , wherein the oxidizer comprises hydrogen peroxide.
12. The composition of claim 1 , comprising both a copper polishing inhibitor and a copper complexing agent.
13. The composition of claim 1 , wherein the copper polishing inhibitor is an azole compound, an anionic or an amphoteric surfactant having a carbon chain length of greater than or equal to 6, or a mixture thereof.
14. The composition of claim 1 , wherein the copper complexing agent is a di-carboxylic acid, a di-phosphonic acid, a di-sulfonic acid, an amino acid, a di-amine, or a mixture thereof.
15. The composition of claim 1 , having an electrical conductivity of less than 1000 μS/cm.
16. 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.
17. The composition of claim 1 , wherein the colloidal silica has a density of greater than 1.90 g/cm 3 .
18. The composition of claim 1 , wherein a molar ratio of the aminosilane compound or the phosphonium silane compound to silica in the colloidal silica abrasive particles is less than 10 percent.
19. The composition of claim 1 , wherein:
the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV;
the composition includes both a copper polishing inhibitor and a copper complexing agent;
the copper polishing inhibitor is an azole compound, an anionic or an amphoteric surfactant having a carbon chain length of greater than or equal to 6, or a mixture thereof;
the complexing agent is a polycarboxylic acid, a poly-phosphonic acid, a di-sulfonic acid, an amino acid, a di-amine, or a mixture thereof; and
the composition has a pH in a range from about 3 to about 6.
20. A chemical-mechanical polishing composition comprising:
a water based liquid carrier;
colloidal silica abrasive particles dispersed in the liquid carrier;
a chemical species incorporated in the colloidal silica abrasive particles internal to an outer surface thereof, wherein the colloidal silica abrasive particles have a permanent positive charge of at least 13 mV, wherein the chemical species is a nitrogen-containing compound or a phosphorus-containing compound;
an oxidizer;
at least one of a copper polishing inhibitor and a copper complexing agent; and
a pH in a range from about 3 to about 7;
wherein the chemical species is not an aminosilane compound.
21. The composition of claim 20 , wherein the colloidal silica abrasive particles have a mean particle size in a range from about 30 to about 70 nm.
22. The composition of claim 20 , comprising from about 2 to about 6 weight percent of the colloidal silica abrasive particles.
23. The composition of claim 20 , wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.
24. The composition of claim 20 , 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.
25. The composition of claim 20 , wherein the oxidizer comprises hydrogen peroxide.
26. The composition of claim 20 , comprising both a copper polishing inhibitor and a copper complexing agent.
27. The composition of claim 26 , wherein:
the copper polishing inhibitor is an azole compound, an anionic or an amphoteric surfactant having a carbon chain length of greater than or equal to 6, or a mixture thereof; and
the copper complexing agent is a di-carboxylic acid, a di-phosphonic acid, a di-sulfonic acid, an amino acid, a di-amine, or a mixture thereof.
28. The composition of claim 20 , wherein the colloidal silica abrasive particles have a core-shell structure in which an outer shell is disposed over an inner core, the chemical species being incorporated in the outer shell.
29. The composition of claim 20 , wherein a molar ratio of the chemical species to silica in the colloidal silica abrasive particles is less than 10 percent.
30. A method for chemical-mechanical polishing a substrate including a copper layer, a copper barrier layer, and a dielectric layer, 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 copper layer, the copper barrier layer, and the dielectric layer from the substrate and thereby polish the substrate.
31. The method of claim 30 , wherein the dielectric layer is silicon oxide and a polishing rate of the dielectric layer is greater than 1000 Å/min at a downforce of 1.5 psi or less.
32. The method of claim 30 , wherein a dielectric:copper polishing rate selectivity is in a range from about 5:1 to about 2:1 at a downforce of 1.5 psi or less.
33. The method of claim 30 , wherein the copper barrier comprises TaN and a polishing rate of the TaN is greater than 400 Å/min at a downforce of 1.5 psi or less.
34. The method of claim 30 , wherein the copper barrier comprises TaN and a dielectric:TaN polishing rate selectivity is in a range from about 3:1 to about 1:1.
35. A method for manufacturing a chemical-mechanical polishing composition, the method comprising:
(a) providing a liquid solution;
(b) combining the liquid solution, a silica producing compound, and an aminosilane compound thereby causing colloidal silica particles to grow such that a dispersion is obtained including colloidal silica particles having the aminosilane compound incorporated therein; and
(c) admixing at least one of a copper complexing agent and a copper polishing inhibitor in the dispersion and adjusting the pH of the dispersion to a value in a range from about 3 to about 7 to obtain a chemical-mechanical polishing composition.
36. The method of claim 35 , further comprising:
(d) adding hydrogen peroxide to the chemical-mechanical polishing composition prior to a chemical-mechanical polishing operation.