Claims
- 1. A method for removing at least a portion of a silicon dioxide layer from a substrate comprising:
(a) admixing a salt, a soluble cerium compound including Ce4+ ions; an oxidizing agent having a oxidation potential greater than Ce4+, and de-ionized water to give a chemical mechanical polishing composition having a pH of from about 3.0 to about 11.0; (b) applying the chemical mechanical polishing composition to the substrate; and (c) removing at least a portion of the silicon oxide layer from the substrate by bringing a pad into contact with the substrate and moving the pad in relation to the substrate.
- 2. The method of claim 1, wherein the substrate is a layered substrate comprising at least one layer of silicon dioxide and at least one layer of silicon nitride.
- 3. The method of claim 1, wherein the silicon oxide is removed from the substrate at a rate at least five-fold greater than the removal rate of silicon nitride.
- 4. The method of claim 1, wherein the oxidizing agent is ammonium persulfate.
- 5. The method of claim 1, wherein the salt and soluble cerium compound is ammonium cerium nitrate.
- 6. The method of claim 1, including at least one metal oxide abrasive selected from the group including alumina, titania, zirconia, germania, silica, ceria and mixtures thereof.
- 7. The method of claim 1, wherein the metal oxide abrasive is silica.
- 8. A method for removing at least a portion of a silicon dioxide layer deposited on a silicon wafer including a silicon nitride layer comprising:
(a) mixing from about 2 to about 15 wt. % silica, from about 0.05 to about 10 wt. % ammonium cerium nitrate, from about 0.05 to about 5.0 wt. % ammonium persulfate, at least one chelating agent and de-ionized water to give a chemical mechanical polishing slurry having a pH of between about 3.8 to about 5.5; (b) applying the chemical mechanical polishing slurry to a pad; (c) rotating the pad; and (d) removing at least a portion of the silicon dioxide layer by bringing the rotating pad into contact with the wafer and rotating the wafer in relation to the rotating pad.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is divisional of co-pending U.S. patent application Ser. No. 08/994,894, filed on Dec. 19, 1997, which is a continuation-in-part of U.S. patent application Ser. No. 08/774,488 filed on Dec. 30, 1996, now U.S. Pat. No. 5,759,917, issued on Jun. 2, 1998.
Divisions (1)
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Number |
Date |
Country |
Parent |
08994894 |
Dec 1997 |
US |
Child |
10694408 |
Oct 2003 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
08774488 |
Dec 1996 |
US |
Child |
08994894 |
Dec 1997 |
US |