Method of manufacturing a fixed abrasive material

• US 20040166790A1
• Filed: 02/21/2003
• Published: 08/26/2004
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Dow Global Technologies, Inc. (Dow, Inc.), Groundhog Technologies, Inc.
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Grier, Laura A., Balijepalli, Sudhakar, Aldrich, Dale J.
• Granted Patent: US 7,066,801 B2
• Time in Patent Office: Days
• US Class Current: 451/526
• CPC Class Codes: B24D 13/147 comprising assemblies of felted or spongy material; comprising pads surrounded by a flexible material
• CPC Class Codes: B24D 18/00 Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
• CPC Class Codes: B24D 3/32 for porous or cellular structure

Abstract

Provided is a method for manufacturing a fixed abrasive material suitable for use in CMP planarization pads from an aqueous polymer dispersion that also includes abrasive particles that involves frothing the polymer dispersion, applying the froth to a substrate, mold or carrier and curing the froth to form a fixed abrasive material having an open cell structure containing between about 5 and 85 wt % abrasive particles and a dry density of about 350 kg/m³ to 1200 kg/m³.

Claims

1. A method of forming a fixed abrasive material comprising:

forming an aqueous dispersion, the aqueous dispersion including

at least one of a polymer and a polymer forming mixture,

abrasive particles, and

a surfactant;

injecting a frothing agent into the aqueous dispersion;

mechanically frothing the aqueous dispersion and the frothing agent to form a substantially uniform froth;

curing the froth to form an open cell foam having interconnected cells and a polymer matrix wherein the abrasive particles are distributed substantially uniformly throughout the polymer matrix.

2. A method of forming a fixed abrasive material according to claim 1, wherein:

the cells have a median cell diameter, the median cell diameter being less than about 300 μ

m.

3. A method of forming a fixed abrasive material according to claim 1, wherein:

the abrasive particles have an average particle size of less than about 2 μ

m.

4. A method of forming a fixed abrasive material according to claim 3, wherein:

the abrasive particles include at least one particulate material selected from a group consisting of alumina, ceria, silica, titania and zirconia.

5. A method of forming a fixed abrasive material according to claim 4, wherein:

the abrasive particles constitute between about 20 weight percent and about 70 weight percent of the polymer matrix;

the froth has a viscosity between about 5,000 and 15,000 cps and a density of between about 500 and 1500 grams per liter; and

the open cell foam has a porosity of between about 20 and 40 percent and a median pore diameter of less than about 200 μ

m.

6. A method of forming a fixed abrasive material according to claim 1, wherein:

the polymer matrix includes a polyurethane.

7. A method of forming a fixed abrasive material according to claim 1, wherein:

the surfactant includes at least a frothing surfactant and a foam stabilizing surfactant.

8. A method of forming a fixed abrasive material according to claim 1, wherein:

the aqueous dispersion further includes a viscosity modifier.

9. A method of forming a fixed abrasive material according to claim 1, wherein:

the aqueous dispersion has

an organic content of less than about 60 weight percent;

an inorganic content of less than about 60 weight percent; and

a surfactant content of between about 1 and 20 weight percent.

10. A method of forming a fixed abrasive material according to claim 9, further wherein:

the aqueous dispersion has

a viscosity modifier content of between about 1 and 10 weight percent.

11. A method of forming a fixed abrasive material according to claim 10, wherein:

the surfactant includes a mixture of

a sodium sulfosuccinimate,

an ammonium stearate, and

a sulfosuccinate sodium salt.

12. A method of forming a fixed abrasive material according to claim 11, wherein:

the sodium sulfosuccinimate is present in an amount between about 1 and 6 parts, the ammonium stearate is present in an amount between about 3 and 15 parts, and the sulfosuccinate sodium salt is present in an amount between about 1 and 6 parts.

13. A method of forming a fixed abrasive material according to claim 12, wherein:

the sodium sulfosuccinimate, the ammonium stearate, and the sulfosuccinate sodium salt are present in a ratio of about 1;

3;

1.

27. A fixed abrasive pad comprising:

a fixed abrasive material layer, the fixed abrasive material being formed by the method of claim 1;

and

a backing layer to which the fixed abrasive material layer is affixed.

28. A fixed abrasive pad according to claim 27, wherein:

the abrasive particles constitute between about 20 weight percent and about 70 weight percent of the fixed abrasive material;

the fixed abrasive material has a foam density of between about 0.75 and 0.95 grams/cm³ and a porosity of between about 20 and 40 percent.

29. A fixed abrasive pad according to claim 27, wherein:

the open cell foam structure of the fixed abrasive material has a median pore diameter of less than about 200 μ

m.

30. A fixed abrasive pad according to claim 27, wherein:

the fixed abrasive material layer will release free abrasive particles from the polymer matrix when subjected to conditioning at a pH of between about 7 and 10;

and further wherein

the fixed abrasive material layer will release substantially no free abrasive particles from the polymer matrix when subjected to conditioning at a pH of about 4 or less.

31. A fixed abrasive pad according to claim 27, wherein:

the fixed abrasive material layer has a thickness of less than about 15 mm.

32. A fixed abrasive pad according to claim 27, wherein:

the backing layer is a polymeric material, and

the fixed abrasive material layer was formed by curing a froth layer deposited on the backing layer, the froth having a viscosity between about 5,000 and 15,000 cps and a density of between about 500 and 1500 grams per liter.

33. A fixed abrasive pad according to claim 32, wherein:

the backing layer is a polycarbonate, and

the froth layer is cured at a temperature above about 70°

C.

14. A method of forming a fixed abrasive polishing pad comprising:

forming an aqueous dispersion, the aqueous dispersion including

at least one of a polymer and a polymer forming mixture,

abrasive particles, the abrasive particles having an average particle size of less than about 2 μ

m, and

a surfactant;

injecting a frothing agent into the aqueous dispersion;

mechanically frothing the aqueous dispersion and the frothing agent to form a substantially uniform froth;

applying a layer of the froth to a substrate material;

curing the layer of the forth to form a layer of open cell foam comprising interconnected cells and a polymer matrix wherein the abrasive particles are distributed substantially uniformly throughout the polymer matrix.

15. A method of forming a fixed abrasive polishing pad according to claim 14, wherein:

the aqueous dispersion includes at least

an alloyed aliphatic polyester based urethane and a polyacrylate as a first component and

a self-crosslinking aliphatic urethane as a second component.

16. A method of forming a fixed abrasive polishing pad according to claim 15, wherein:

the first and second components are present in the aqueous dispersion in a weight ratio of between about 4;

1 and 1;

4.

17. A method of forming a fixed abrasive polishing pad according to claim 14, wherein:

the abrasive particles constitute one or more particulate materials selected from a group consisting of alumina, ceria, silica, titania and zirconia.

18. A method of forming a fixed abrasive polishing pad according to claim 17, wherein:

the abrasive particles constitute between about 20 weight percent and about 70 weight percent of the polymer matrix.

19. A method of forming a fixed abrasive polishing pad according to claim 14, wherein:

the surfactant includes at least a frothing surfactant and a foam stabilizing surfactant.

20. A method of forming a fixed abrasive polishing pad according to claim 19, wherein:

the aqueous dispersion further includes a viscosity modifier.

21. A method of forming a fixed abrasive polishing pad according to claim 14, wherein:

the aqueous dispersion has

an organic content of less than about 60 weight percent;

an inorganic content of less than about 60 weight percent; and

a surfactant content of between about 1 and 20 weight percent.

22. A method of forming a fixed abrasive polishing pad according to claim 21, further wherein:

the aqueous dispersion has

a viscosity modifier content of between about 1 and 10 weight percent.

23. A method of forming a fixed abrasive polishing pad according to claim 22, wherein:

the surfactant includes a mixture of

a sodium sulfosuccinimate,

an ammonium stearate, and

a sulfosuccinate sodium salt.

24. A method of forming a fixed abrasive polishing pad according to claim 23, wherein:

the sodium sulfosuccinimate is present in an amount between about 1 and 6 parts, the ammonium stearate is present in an amount between about 3 and 15 parts, and the sulfosuccinate sodium salt is present in an amount between about 1 and 6 parts.

25. A method of forming a fixed abrasive polishing pad according to claim 24, wherein:

the sodium sulfosuccinimate, the ammonium stearate, and the sulfosuccinate sodium salt are present in a ratio of about 1;

3;

1.

26. A method of forming a fixed abrasive polishing pad according to claim 25, wherein:

the abrasive particles constitute between about 20 weight percent and about 70 weight percent of the polymer matrix;

the froth has a viscosity between about 5,000 and 15,000 cps and a density of between about 500 and 1500 grams per liter; and

the open cell foam has a porosity of between about 20 and 40 percent and a median pore diameter of less than about 200 μ

m.