Polishing Slurry

• US 20090278080A1
• Filed: 01/05/2006
• Published: 11/12/2009
• Est. Priority Date: 01/05/2005
• Status: Active Grant

• Current Assignee: Nitta Haas Incorporated (Nitta Corporation)
• Original Assignee: Nitta Haas Incorporated (Nitta Corporation)
• Inventors: Morioka, Yoshitaka, Tanaka, Rika, Nitta, Hiroshi, Ohta, Yoshiharu
• Granted Patent: US 8,062,548 B2
• Time in Patent Office: Days
• US Class Current: 252/79.100
• 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: C23F 3/06 with acidic solutions
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]

Abstract

An object of one embodiment of the present invention is to provide a polishing slurry which can reduce dishing and erosion of a to-be-polished semiconductor wafer. The polishing slurry contains an oxidizing agent and two or more kinds of abrasive grains for polishing, i.e., fumed silica and colloidal silica. A ratio (selectivity ratio) between a polishing rate of a metal film such as a tungsten film and a polishing rate of an insulating film (oxide film) such as a SiO₂ film can be adjusted by changing a mixing ratio between fumed silica and colloidal silica, and dishing and erosion of the semiconductor wafer can be thus reduced.

Claims

1. A polishing slurry for use in chemical mechanical polishing, comprising an oxidizing agent and two or more kinds of abrasive grains, the oxidizing agent being potassium iodate.

2. The polishing slurry of claim 1, wherein the abrasive grains are silica abrasive grains.

3. The polishing slurry of claim 2, wherein fumed silica and colloidal silica are included as the two or more kinds of the abrasive grains.

4. The polishing slurry of claim 3, comprising an acid and having a pH of 1 to 6.

5. The polishing slurry of claim 3, wherein a mixing ratio of the colloidal silica to a total amount of both kinds of silica of the fumed silica and the colloidal silica falls in a range of 1% to 99%.

6. The polishing slurry of claim 1, which is used for polishing a substrate having an insulating film and metal film formed thereon.

7. The polishing slurry of claim 4, wherein a mixing ratio of the colloidal silica to a total amount of both kinds of silica of the fumed silica and the colloidal silica falls in a range of 1% to 99%.

8. The polishing slurry of claim 2, which is used for polishing a substrate having an insulating film and metal film formed thereon.

9. The polishing slurry of claim 3, which is used for polishing a substrate having an insulating film and metal film formed thereon.

10. The polishing slurry of claim 4, which is used for polishing a substrate having an insulating film and metal film formed thereon.

11. The polishing slurry of claim 5, which is used for polishing a substrate having an insulating film and metal film formed thereon.