Method of polishing a silicon-containing dielectric

• US 7,442,645 B2
• Filed: 02/02/2004
• Issued: 10/28/2008
• Est. Priority Date: 02/03/2003
• Status: Expired due to Term

• Current Assignee: CMC Materials, Inc. (Entegris Incorporated)
• Original Assignee: Cabot Microelectronics Corporation (Entegris Incorporated)
• Inventors: Carter, Phillip W., Johns, Timothy P.
• Primary Examiner(s): Tran; Binh X
• Application Number:
  US10/543,848
• Publication Number:
  US 20060196848A1
• Time in Patent Office: 1,730 Days
• Field of Search: 438/692, 438/693, 438/690, 438/691, 216/89
• US Class Current: 438/690
• CPC Class Codes: C03C 19/00 Surface treatment of glass, not in the form of fibres or filaments, by mechanical means sand-blasting, grinding, or polishing glass B24
• CPC Class Codes: C09G 1/02 containing abrasives or grinding agents abrasives as such C09K3/14; polishing of semi-conductors H01L
• CPC Class Codes: C09K 3/1463 Aqueous liquid suspensions
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step

Abstract

The inventive method of polishing a silicon-containing dielectric layer involves the use of a chemical-mechanical polishing system comprising (a) an inorganic abrasive, (b) a polishing additive, and (c) a liquid carrier, wherein the polishing composition has a pH of about 4 to about 6. The inventive chemical-mechanical polishing system comprises (a) ceria, (b) a polishing additive, and (c) a liquid carrier, wherein the polishing system has a pH of about 4 to about 6.

Claims

1. A method of polishing a substrate comprising:

(i) contacting a substrate comprising a silicon dioxide layer and a silicon nitride layer with a chemical-mechanical polishing system comprising;

(a) an inorganic abrasive,

(b) a polishing additive bearing a functional group with a pK_a of about 3 to about 9, wherein the polishing additive is selected from the group consisting of aniline and arylamines having one or more substituents selected from the group consisting of carboxylic acids, sulfonic acids, phosphonic acids, thiol groups, sulfonamides, salts thereof, and combinations thereof, and

(c) a liquid carrier,

wherein the polishing system has a pH of about 7 or less and does not contain a significant amount of cross-linked polymer abrasive particles that are electrostatically associated with the inorganic abrasive, and

(ii) abrading at least a portion of the silicon dioxide layer to polish the substrate.

2. The method of claim 1, wherein the polishing additive bears a functional group with a pK_a of about 3 to about 8.

3. The method of claim 1, wherein the polishing additive is selected from the group consisting of aniline, anthranilic acid, orthanilic acid, salts thereof, and combinations thereof.

4. The method of claim 1, wherein the polishing additive bears a functional group with a pK_a of about 4 to about 9.

5. The method of claim 4, wherein the inorganic abrasive has a positive zeta potential.

6. The method of claim 4, wherein the polishing composition has a conductivity of about 2000 μ

S/cm or less.

7. The method of claim 4, wherein the inorganic abrasive is fixed onto a polishing surface of a polishing pad.

8. The method of claim 4, wherein the polishing system is colloidally stable over a period of at least 24 hours.

9. The method of claim 4, wherein the polishing system further comprises a surfactant.

10. The method of claim 4, wherein the polishing system has a pH of about 2 to about 6.5.

11. The method of claim 10, wherein the polishing system has a pH of about 3.5 to about 5.5.

12. The method of claim 4, wherein the inorganic abrasive is selected from the group consisting of alumina, ceria, silica, titania, chromia, zirconia, silicon carbide, boron nitride, magnesia, iron oxide, co-formed products thereof, and combinations thereof.

13. The method of claim 12, wherein the inorganic abrasive is ceria.

14. The method of claim 4, wherein the polishing system comprises about 2 wt. % or less inorganic abrasive.

15. The method of claim 14, wherein the polishing system comprises about 0.5 wt. % or less inorganic abrasive.