Compositions and methods for selective polishing of silicon nitride materials

Patent metadata

Field	Value
Publication number	US-9633863-B2
Application number	US-201213546552-A
Country	US
Kind code	B2
Filing date	Jul 11, 2012
Priority date	Jul 11, 2012
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

The present invention provides an acidic aqueous polishing composition suitable for polishing a silicon nitride-containing substrate in a chemical-mechanical polishing (CMP) process. The composition, at point of use, preferably comprises about 0.01 to about 2 percent by weight of at least one particulate ceria abrasive, about 10 to about 1000 ppm of at least one non-polymeric unsaturated nitrogen heterocycle compound, 0 to about 1000 ppm of at least one cationic polymer, optionally, 0 to about 2000 ppm of at least one polyoxyalkylene polymer, and an aqueous carrier therefor. The cationic polymer preferably is selected from a poly(vinylpyridine) polymer, a quaternary ammonium-substituted acrylate polymer, a quaternary ammonium-substituted methacrylate polymer, or a combination thereof. Methods of polishing substrates and of selectively removing silicon nitride from a substrate in preference to removal of polysilicon using the compositions are also provided.

First claim

What is claimed is:

1. A chemical-mechanical polishing (CMP) method for selectively removing silicon nitride from a surface of a substrate in preference to removal of polysilicon, the method comprising the steps of:
(a) contacting a surface of a silicon nitride- and polysilicon-containing substrate with a polishing pad and an acidic aqueous CMP composition; and
(b) causing relative motion between the polishing pad and the substrate while maintaining a portion of the CMP composition in contact with the surface between the pad and the substrate for a time period sufficient to abrade silicon nitride from the surface;
wherein the CMP composition comprises:
(i) about 0.1 to about 0.3 percent by weight of a calcined ceria abrasive;
(ii) about 10 to about 1000 ppm of at least one non-polymeric unsaturated nitrogen heterocycle compound;
(iii) 10 to about 1000 ppm of at least one cationic polymer, wherein the cationic polymer comprises a poly(vinylpyridine) polymer, a quaternary ammonium-substituted acrylate polymer, a quaternary ammonium-substituted methacrylate polymer, or a combination of any of the foregoing cationic polymers;
(iv) 200 to about 2000 ppm of at least one polyoxyalkylene polymer, wherein the polyoxyalkylene polymer comprises a poly(ethylene glycol) polymer, a poly(ethylene glycol)-co-poly(propylene glycol) block copolymer, or a combination thereof; and
(v) an aqueous carrier therefor, wherein the CMP composition has a pH in the range of about 3 to about 5.

2. The method of claim 1 wherein the polyoxyalkylene polymer comprises a poly(ethylene glycol) polymer comprising an average number of ethylene glycol monomer units in the range of about 300 to about 1500.

3. The method of claim 1 wherein the non-polymeric unsaturated nitrogen heterocycle compound comprises a pyridine compound.

4. The method of claim 1 wherein the non-polymeric unsaturated nitrogen heterocycle compound comprises a pyridinium compound.

5. Then method of claim 1 wherein the non-polymeric unsaturated nitrogen heterocycle compound comprises 4,4′-trimethylenedipyridine.

6. The method of claim 1 wherein the surface of the substrate also comprises silicon dioxide.

Assignees

• Ward William
• Cabot Microelectronics Corp

Inventors

• Ward William

Classifications

• H10P50/283

  by chemical means · CPC title

• H10P50/71

  using masks for conductive or resistive materials · CPC title

• H10P95/062 Primary

  involving a dielectric removal step · CPC title

• H01L21/31053 Primary

  Electricity · mapped topic

• H01L21/32139

  Electricity · mapped topic