Claims
- 1. A composition for polishing a composite comprised of silica and silicon nitride comprising: an aqueous medium, abrasive particles, a surfactant, and a compound which complexes with said silica and silicon nitride, said compound having two or more functional groups each having a dissociable proton, said functional groups being the same or different wherein the pH of said composition is adjusted to a range wherein the removal rate of silicon nitride is effectively shut down while the removal rate of silicon dioxide is not greatly affected.
- 2. A composition according to claim 1 wherein said compound which complexes with silica and silicon nitride contains a benzene ring.
- 3. A composition according to claim 1 wherein said compound which complexes with silica and silicon nitride is a straight chain mono- or di-carboxylic acid or salt which has a secondary hydroxyl group in an alpha position relative to a carboxylate group.
- 4. A composition according to claim 1 wherein said compound which complexes with silica and silicon nitride is a tri- or poly-carboxylic acid or salt which has a secondary or tertiary hydroxyl group in an alpha position relative to a carboxylate group.
- 5. A composition according to claim 1 wherein said abrasive particles comprise ceria.
- 6. A composition according to claim 1 wherein said surfactant comprises a fluorosurfactant.
- 7. A composition according to claim 2 wherein said compound which complexes with silica and silicon nitride is potassium hydrogen phthalate.
- 8. A composition according to claim 1 comprising: water, about 0.2% to about 5% ceria, about 0.5% to about 3.5% potassium hydrogen phthalate, about 0.1% to about 0.5% fluorosurfactant, all percentages by weight, and wherein the pH of said composition is adjusted from about 6 to about 7 by the addition of a base or an amine compound to said composition.
- 9. A composition according to claim 1 wherein the adjusted pH is in the range of about 5 to about 8.
- 10. A composition according to claim 1 wherein the adjusted pH is in the range of about 6.5 to about 7.5.
Parent Case Info
This application claims the benefit of U.S. Provisional Applications No. 60/027,277 filed Sep. 27, 1996. This application is a division of Prior application Ser. No. 08/802,829, now U.S. Pat. No. 5,738,800, which was filed Feb. 19, 1997 by reference.
US Referenced Citations (13)
Divisions (1)
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Number |
Date |
Country |
Parent |
802829 |
Feb 1997 |
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