CMP composition of boron surface-modified abrasive and nitro-substituted sulfonic acid and method of use
A composition and associated method for chemical mechanical planarization (or other polishing) are described. The composition contains a boron surface-modified abrasive, a nitro-substituted sulfonic acid compound, a per-compound oxidizing agent, and water. The composition affords high removal rates for barrier layer materials in metal CMP processes. The composition is particularly useful in conjunction with the associated method for metal CMP applications (e.g., step 2 copper CMP processes).
1. A method of step 2 copper chemical-mechanical planarization, said method comprising the steps of:
A) placing a substrate comprising copper, at least one dielectric material and at least one barrier material in contact with a polishing pad;
B) delivering a step 2 chemical-mechanical planarization composition comprising
a) a boron surface-modified abrasive;
b) a nitro-substituted sulfonic acid compound;
c) an oxidizing agent; and
d) water;
C) polishing the substrate with the step 2 copper chemical-mechanical planarization composition.
2. The method of claim 1 wherein the boron surface-modified abrasive is a colloidal boron surface-modified silica abrasive.
3. The method of claim 1 wherein the boron surface-modified abrasive is present at a weight percent level in the composition ranging from about 0.5 weight % to about 5 weight %.
4. The method of claim 1 wherein the nitro-substituted sulfonic acid compound is selected from the group consisting of 2-nitrobenzenesulfonic acid, 3-nitrobenzenesulfonic acid, 4-nitrobenzenesulfonic acid, and 2,4-dinitrobenzenesulfonic acid.
5. The composition of claim 1 wherein the nitro-substituted sulfonic acid compound is present at a weight percent level in the composition ranging from about 0.5 weight % to about 6 weight %.
6. The method of claim 1 wherein the oxidizing agent is a per-compound.
7. The method of claim 6 wherein the oxidizing agent comprises hydrogen peroxide present at a level ranging from 0.5 weight % to 6 weight % of the total weight of the composition.
8. The method of claim 1 wherein the composition has a pH ranging from 6 to 10.
9. The method of claim 1 further comprising e) a surfactant.
10. The method of claim 9 wherein the suffactant is a nonionic surfactant.
11. The method of claim 1 further comprising e) a corrosion inhibitor.
12. The method of claim 1 , wherein the dielectric material comprises TEOS and the barrier material comprises TaN;
wherein the step 2 chemical-mechanical planarization composition pH is basic, the boron-surface-modified abrasive comprises boron surface-modified silica abrasive and the oxidizing agent comprises a per-type oxidizer; and
wherein during polishing the selectivity for tantalum nitride over TEOS is greater than 1 and the selectivity of tantalum nitride over copper is greater than 1.
13. The method of claim 12 , wherein during polishing the selectivity for tantalum nitride over TEOS is at least 6 and the selectivity of tantalum nitride over copper is at least 8.8.
14. The method of claim 1 wherein the nitro-substituted sulfonic acid compound is 3-nitrobenzenesulfonic acid.
15. The method of claim 1 wherein the nitro-substituted sulfonic acid compound is 2,4-dinitrobenzenesulfonic acid.
16. The method of claim 1 wherein the nitro-substituted sulfonic acid compound comprises at least one of 3-nitro-4-hydroxy-benzenesulfonic acid; 3-nitro-5-hydroxy-benzenesulfonic acid; 2-nitro-4-hydroxy-benzenesulfonic acid; 2-hydroxy-4-nitro-benzenesulfonic acid; and 2-carboxy-4-nitrobenzenesulfonic acid.
17. The method of claim 1 wherein the nitro-substituted sulfonic acid compound comprises one or more nitro moieties and one or more sulfonate moieties attached to a ring structure where the ring is heterocyclic.
18. The method of claim 1 wherein the boron surface-modified abrasive is present at a weight percent level in the composition ranging from 0.01 weight % to 5 weight % of the total weight of the slurry.
19. The method of claim 1 wherein the at least one dielectric material on the substrate is a low-k carbon-doped oxide.
20. A method of step 2 copper chemical-mechanical planarization, said method comprising the steps of:
A) placing a substrate comprising copper, at least one dielectric material and at least one barrier material in contact with a polishing pad;
B) delivering a step 2 chemical-mechanical planarization composition comprising
a) a boron surface-modified abrasive present at a weight percent level in the composition ranging from about 0.5 weight % to about 5 weight %;
b) a nitro-substituted sulfonic acid compound present at a weight percent level in the composition ranging from about 0.5 weight % to about 6 weight %;
c) a per-compound oxidizing agent present at a level ranging from 0.5 weight % to 6 weight % of the total weight of the composition; and
d) water;
C) polishing the substrate with the step 2 copper chemical-mechanical planarization composition.
21. The method of claim 20 wherein the nitro-substituted sulfonic acid compound is 3-nitrobenzenesulfonic acid.
22. The method of claim 20 wherein the nitro-substituted sulfonic acid compound is 2,4-dinitrobenzenesulfonic acid.
23. The method of claim 20 wherein the at least one dielectric material on the substrate is a low-k carbon-doped oxide.