Boron-containing polishing system and method
View Patent ↗The invention provides a chemical-mechanical polishing system comprising an abrasive, a carrier, and either boric acid, or a conjugate base thereof, wherein the boric acid and conjugate base are not present together in the polishing system in a sufficient amount to act as a pH buffer, or a water-soluble boron-containing compound, or salt thereof, that is not boric acid, and a method of polishing a substrate using the chemical-mechanical polishing system.
1. A chemical-mechanical polishing system comprising:
(a) an abrasive and/or polishing pad,
(b) boric acid, or a conjugate base thereof, and
(c) an aqueous carrier,
wherein the boric acid or conjugate base thereof is not present in the polishing system in a sufficient amount to act as a pH buffer.
2. The chemical-mechanical polishing system of claim 1 , wherein the abrasive is a metal oxide.
3. The chemical-mechanical polishing system of claim 2 , wherein the abrasive is selected from the group consisting of alumina, silica, titania, ceria, zirconia, germania, magnesia, co-formed products thereof, and combinations thereof.
4. The chemical-mechanical polishing system of claim 3 , wherein the abrasive is alumina or silica.
5. The chemical-mechanical polishing system of claim 1 , wherein the abrasive is fixed on a polishing pad.
6. The chemical-mechanical polishing system of claim 1 , wherein the abrasive is in particulate form and is suspended in the carrier.
7. The chemical-mechanical polishing system of claim 1 , wherein the carrier is water.
8. The chemical-mechanical polishing system of claim 1 , wherein the system further comprises an oxidizing agent.
9. The chemical-mechanical polishing system of claim 8 , wherein the oxidizing agent is a peroxide or persulfate.
10. The chemical-mechanical polishing system of claim 1 , wherein the system further comprises d film-forming agent.
11. The chemical-mechanical polishing system of claim 10 , wherein the film-farming agent is an azole.
12. The chemical-mechanical polishing system of claim 1 , wherein the system comprises about 0.5 wt.% or more carrier-suspended abrasive particles, about 0.01 wt.% or more boric acid or conjugate base thereof, and water.
13. The chemical-mechanical polishing system of claim 1 , wherein the system further comprises a complexing agent.
14. A method of polishing a substrate comprising:
(i) contacting a substrate with a chemical-mechanical polishing system comprising;
(a) an abrasive and/or polishing pad,
(b) boric acid, or conjugate base thereof, and
(c) an aqueous carrier,
wherein the boric acid or conjugate base thereof is not present in the polishing system in a sufficient amount to act as a pH buffer, and
(ii) abrading at least a portion of the substrate to polish the substrate.
15. The method of claim 14 , wherein the substrate comprises a metal oxide layer and a metal layer.
16. The method of claim 15 , wherein the metal layer comprises copper, tungsten, tantalum, or titanium.