Free radical-forming activator attached to solid and used to enhance CMP formulations

• US 20060117667A1
• Filed: 11/02/2005
• Published: 06/08/2006
• Est. Priority Date: 02/11/2002
• Status: Active Grant

• Current Assignee: Versum Materials US Inc.
• Original Assignee: DuPont Air Products NanoMaterials LLC
• Inventors: Small, Robert J., Siddiqui, Junaid Ahmed, Castillo, Daniel Hernandez
• Granted Patent: US 7,513,920 B2
• Time in Patent Office: Days
• US Class Current: 51/309
• 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: C23F 3/04 Heavy metals
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3169 Working or finishing the interfacing surface of heads, e.g. lapping of heads
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]

Abstract

A CMP composition having: a fluid comprising water and at least one oxidizing compound that produces free radicals when contacted with an activator; and a plurality of particles having a surface and comprising at least one activator selected from ions or compounds of Cu, Fe, Mn, Ti, or mixtures thereof disposed on said surface, wherein at least a portion of said surface comprises a stabilizer. Preferred activators are selected from inorganic oxygen-containing compounds of B, W, Al, and P, for example borate, tungstate, aluminate, and phosphate. The activators are preferably ions of Cu or Fe. Surprisingly, as little as 0.2 ppm and 12 ppm of activator is useful, if the activator-containing particles are suspended in the fluid as a slurry. Advantageously, certain organic acids, and especially dihydroxy enolic acids, are included in an amount less than about 4000 ppm. Advantageously, activator is coated onto abrasive particles after the particles have been coated with stabilizer.

Claims

1. A slurry composition for chemical-mechanical polishing a substrate, said slurry composition comprising:

a fluid comprising water and at least one oxidizing compound that produces free radicals when contacted with an activator, and wherein the fluid pH is between about 2 to about 8; and

a plurality of particles having a surface and comprising at least one activator selected from ions or compounds of Cu, Fe, Mn, Ti, or mixtures thereof disposed on said surface, wherein at least a portion of said surface comprises a stabilizer selected from inorganic compounds of B, W, and Al, wherein if the particle body is alumina then the stabilizer comprises B, W, or mixture thereof.

2. The slurry of claim 1 further comprising α

,β

-dihydroxy enolic compound.

3. The slurry of claim 2 wherein the α

,β

-dihydroxy enolic compound is ascorbic acid and the similar erythorbic acid, or derivatives and/or mixtures thereof.

4. The slurry of claim 3, wherein the pH of the fluid is between about 6 and about 7.

5. The slurry of claim 1 wherein:

said particles comprise silica, alumina, ceria, spinel, or combination thereof;

said stabilizer comprises B; and

said activator selected from the group consisting of Cu, Fe, Mn, or mixture thereof, said activator being associated with the surface of the abrasive particle and being present in an amount sufficient to provide at least a 20% higher substrate removal rate during chemical mechanical polishing of said substrate, compared to the substrate removal rate during polishing the substrate under the same conditions but wherein the abrasive particle does not comprise activator.

6. The slurry of claim 5, wherein said stabilizer is associated with the surface of the particle, said stabilizer forming a layer between at least a portion of said activator and said particle surface.

7. The slurry of claim 1, wherein said activator is present in an amount between about 0.2 ppm and 12 ppm as metal, based on the weight of the slurry.

8. The slurry composition of claim 7 wherein the activator is present in an amount between about 3 ppm and 8 ppm as metal, based on the weight of the slurry.

9. The slurry composition of claim 7 further comprising between 0.01% and 0.5% by weight total of ascorbic acid, alkyne diols, citric acid, lactic acid, glycolic acid, and/or salicylic acid, or combinations thereof.

10. An abrasive particle for use in chemical mechanical polishing, said abrasive particle comprising:

a body comprising silica, alumina, ceria, spinel, or combination thereof;

a stabilizing coating disposed on the exterior of the particle body, said stabilizing coating comprising an inorganic compound comprising B, W, Al, or mixtures thereof, wherein if the particle body is alumina then the stabilizer comprises B, W, or mixture thereof; and

an activator selected from the group consisting of Cu, Fe, Mn, Ti, or mixture thereof, said activator being associated with the surface of the abrasive particle and being present in an amount sufficient to provide at least a 20% higher substrate removal rate during chemical mechanical polishing of said substrate when used with a liquid comprising a per-type oxidizer capable of producing free radicals, compared to polishing the substrate with the same liquid and under the same conditions but wherein the abrasive particle does not comprise activator.

11. The abrasive particle of claim 10, wherein the surface of the particle body is modified by the stabilizer prior to the activator becoming associated with the surface of the particle.

12. The abrasive particle of claim 11, wherein at least 80% of the surface sites of the particle are coated with said stabilizer.

13. The abrasive particle of claim 11, wherein said stabilizer is associated with the surface of the particle, said stabilizer forming a layer between at least a portion of said activator and said particle surface.

14. The abrasive particle of claim 11, wherein the particle body comprises silica, the stabilizer comprises B, and the activator is present in an amount between 0.01% to 3% by weight of the weight of the particles.

15. The abrasive particle of claim 14, wherein said stabilizer is associated with the surface of the particle, said stabilizer forming a layer between said activator and said particle surface.

16. The abrasive particle of claim 10, wherein at least 80% of the surface sites of the particle are coated with said stabilizer.

17. The abrasive particle of claim 16, wherein the stabilizer comprises B, and the activator is present in an amount between 0.01% to 3% by weight of the weight of the particles.

18. The abrasive particle of claim 17 wherein the activator comprises iron.

19. The abrasive particle of claim 10, wherein the abrasive particle is disposed on the surface of a polishing pad.

20. A slurry composition for chemical-mechanical polishing a substrate, said slurry composition comprising:

a) a fluid comprising water and at least one oxidizing compound that produces free radicals when contacted with an activator, and wherein the fluid pH is between about 2 to about 8; and

b) a plurality of particles having a surface and comprising;

i) a stabilizer selected from borate, tungstate, aluminate, phosphoric acid, pyrophosphoric acid, stannate, a silanol, or mixtures thereof, wherein if the particle is alumina then the stabilizer is not aluminate; and

ii) at least one activator selected from ions or compounds of Ce, Cu, Fe, Mn, Ti, or mixtures thereof disposed on said surface, wherein said activator metal is present in an amount between about 0.2 ppm and 12 ppm based on the weight of the slurry.

21. The slurry composition of claim 20 wherein the activator is present in an amount between about 3 ppm and 8 ppm.

22. The slurry composition of claim 20 wherein said stabilizer forming a layer between at least a portion of said activator and said particle surface.

23. The slurry of claim 20 further comprising an α

,β

-dihydroxy enolic compound.

24. The slurry of claim 23, wherein the pH of the fluid is between about 6 and about 7.

25. The slurry of claim 20, wherein the activator is selected from Cu, Fe, Mn, or mixtures thereof.

26. The slurry of claim 25, wherein a stabilizer is selected from borate, tungstate, aluminate, or mixtures thereof.