Polishing medium for chemical-mechanical polishing, and method of polishing substrate member

• US 20060124597A1
• Filed: 02/13/2006
• Published: 06/15/2006
• Est. Priority Date: 08/17/1999
• Status: Active Grant

• Current Assignee: Akiko Igarashi, Hiroki Terasaki, Takeshi Uchida, Yasuo Kamigata, Yasushi Kurata
• Original Assignee: Akiko Igarashi, Hiroki Terasaki, Takeshi Uchida, Yasuo Kamigata, Yasushi Kurata
• Inventors: Kamigata, Yasuo, Uchida, Takeshi, Kurata, Yasushi, Terasaki, Hiroki, Igarashi, Akiko
• Granted Patent: US 7,319,072 B2
• Time in Patent Office: Days
• US Class Current: 216/88
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• 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 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation

Abstract

This invention provides a polishing medium for chemical-mechanical polishing, comprising an oxidizing agent for a conductor, a protective-film-forming agent for protecting a metal surface, an acid, and. water; (1) the polishing medium having a pH of 3 or less, and the oxidizing agent being in a concentration of from 0.01 to 3% by weight, or (2) the polishing medium containing abrasive grains having an average particle diameter of 50 nm or less, and the abrasive grains having standard deviation of particle size distribution in a value of more than 5 nm.

Claims

1. A method of polishing a substrate member, comprising a step of polishing a barrier layer containing tantalum, a tantalum alloy or a tantalum compound by the use of a polishing medium for chemical-mechanical polishing, said polishing medium including:

an oxidizing agent;

a protective-film-forming agent;

an acid; and

water, wherein;

said polishing medium does not include abrasive grains,

said polishing medium has a pH of 3 or less, and

said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight, and wherein;

the polishing medium for chemical-mechanical polishing has, under polishing conditions of a polishing pressure of 25 kPa and relative speed of substrate member to polishing platen of 18 m/minute;

a polishing-rate ratio (Ta/Cu) between tantalum and copper or a copper alloy of more than 1;

a polishing-rate ratio (TaN/Cu) between tantalum nitride and copper or a copper alloy of more than 1;

a polishing-rate ratio (Ta/SiO₂) between tantalum and silicon dioxide of more than 10; and

a polishing-rate ratio (TaN/SiO₂) between tantalum nitride and silicon dioxide of more than 10.

2. The method according to claim 1, wherein said medium has a pH of 2.49 to 2.95.

3. The method according to claim 1, wherein said oxidizing agent has a concentration of 0.15 to 1.5% by weight.

4. The method according to claim 1, wherein said oxidizing agent has a concentration of 0.15 to 1.5% by weight.

5. A method of polishing a substrate member having a barrier layer containing at least one of tantalum, a tantalum alloy and a tantalum compound overlying an insulator and a conductor layer containing at least one of copper, a copper alloy and copper oxide on the barrier layer, comprising:

chemical-mechanical polishing the conductor layer, using a first chemical-mechanical polishing medium, so as to remove portions of the conductor layer and expose portions of the barrier layer, in a first step; and

thereafter, chemical-mechanical polishing exposed portions of the barrier layer, using a second chemical-mechanical polishing medium, wherein the second chemical-mechanical polishing medium comprises;

an oxidizing agent;

a protective-film-forming agent;

an acid; and

water, wherein;

said polishing medium has a pH of 3 or less, and

said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight.

6. The method according to claim 5, wherein said medium has a pH of 2.49 to 2.95.

7. The method according to claim 5, wherein said oxidizing agent has a concentration of 0.15 to 1.8% by weight.

8. The method according to claim 5, wherein said oxidizing agent has a concentration of 0.15 to 1.5% by weight.

9. The method according to claim 5, wherein the second chemical-mechanical polishing medium does not include abrasive particles.

10. The method according to claim 5, wherein the second chemical-mechanical polishing medium contains abrasive particles.

11. The method according to claim 5, wherein said first polishing medium is different from said second polishing medium, and polishes the at least one of copper, copper alloy and copper oxide at a higher polishing rate than the polishing rate by the first polishing medium of said at least one of tantalum, tantalum alloy and tantalum compound.

12. The method according to claim 5, wherein said insulator includes dales, and the barrier layer is provided in said dales and said conductor layer fills said dales.

13. A method of polishing a substrate member comprising a step of polishing a surface including a wiring layer and a barrier layer, by applying to the surface a polishing medium for chemical-mechanical polishing, adapted to polish a barrier layer of tantalum, a tantalum alloy or a tantalum compound, which is a barrier layer for a wiring layer of copper, copper alloy, or copper oxide, said polishing medium comprising:

an oxidizing agent;

a protective-film-forming agent;

an acid; and

water, wherein;

said polishing medium does not include abrasive grains,

said polishing medium has a pH of 3 or less, and

said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight, and wherein;

as a polishing condition, polishing pressure is 25 kPa and relative speed of substrate member to polishing platen is 18 m/minute, the polishing medium for chemical-mechanical polishing has;

a polishing-rate ratio (Ta/Cu) between tantalum and copper or a copper alloy of more than 1;

a polishing-rate ratio (TaN/Cu) between tantalum nitride and copper or a copper alloy of more than 1;

a polishing-rate ratio (Ta/SiO₂) between tantalum and silicon dioxide of more than 10; and

a polishing-rate ratio (TaN/SiO₂) between tantalum nitride and silicon dioxide film of more than 10.

14. A method of polishing a substrate member comprising a step of polishing a barrier layer containing tantalum, a tantalum alloy or a tantalum compound, by applying to the barrier layer a polishing medium for chemical-mechanical polishing, adapted to polish a barrier layer of tantalum, a tantalum alloy or a tantalum compound, which is a barrier layer for a conductor of copper, copper alloy, or copper oxide, the polishing medium comprising:

an oxidizing agent;

a protective-film-forming agent;

abrasive grains;

an acid; and

water, wherein;

said polishing medium has a pH of 3 or less, and

said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight; and

wherein;

as a polishing condition, polishing pressure is 25 kPa and relative speed of substrate member to polishing platen is 18 m/minute, the polishing medium has;

a polishing-rate ratio (Ta/Cu) between tantalum and copper or a copper alloy of more than 1;

a polishing-rate ratio (TaN/Cu) between tantalum nitride and copper or a copper alloy of more than 1;

a polishing-rate ratio (Ta/SiO₂) between tantalum and silicon dioxide of more than 10; and

a polishing-rate ratio (TaN/SiO₂) between tantalum nitride and silicon dioxide film of more than 10.

15. A method of polishing a substrate member comprising a step of polishing a surface including a wiring layer and a barrier layer, by applying to the surface a polishing medium for chemical-mechanical polishing, adapted to polish a barrier layer of tantalum, a tantalum alloy or a tantalum compound, which is a barrier layer for a conductor of copper, copper alloy, or copper oxide, the polishing medium comprising:

an oxidizing agent;

a protective-film-forming agent;

abrasive grains;

an acid; and

water, wherein;

said polishing medium has a pH of 3 or less, and

said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight; and

wherein;

as a polishing condition, polishing pressure is 25 kPa and relative speed of substrate member to polishing platen is 18 m/minute, the polishing medium has;

a polishing-rate ratio (Ta/Cu) between tantalum and copper or a copper alloy of more than 1;

a polishing-rate ratio (TaN/Cu) between tantalum nitride and copper or a copper alloy of more than 1;

a polishing-rate ratio (Ta/SiO₂) between tantalum and silicon dioxide of more than 10; and

a polishing-rate ratio (TaN/SiO₂) between tantalum nitride and silicon dioxide film of more than 10.