CVD diamond coated substrate for polishing pad conditioning head and method for making same

• US 5,921,856 A
• Filed: 06/15/1998
• Issued: 07/13/1999
• Est. Priority Date: 07/10/1997
• Status: Expired due to Term

• Current Assignee: Morgan Advanced Ceramics Inc.
• Original Assignee: sp3, Inc.
• Inventors: Zimmer, Jerry W.
• Primary Examiner(s): Scherbel, David A.
• Assistant Examiner(s): BANKS, DERRIS HOLT
• Application Number:
  US09/094,930
• Time in Patent Office: 393 Days
• Field of Search: 51/294, 51/295, 451/526, 451/529, 451/534, 451/539, 451/533, 451/528, 451/532
• US Class Current: 451/539
• CPC Class Codes: B24B 37/04 designed for working plane surfaces
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: B24D 11/00 Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
• CPC Class Codes: B24D 18/0018 by electrolytic deposition

Abstract

A flat substrate polishing pad conditioning head for a chemical-mechanical-planarization apparatus is provided which has been shown to double the useable life of a polishing pad used to planarize and/or polish both oxide and metal outer layers in the processing of semiconductor wafers and to provide for more uniform polishing during the life of the polishing pad. The polishing pad conditioning head (24) comprises a suitable substrate (26), a diamond grit (28) that is evenly distributed over the surface of the substrate (26) and a CVD diamond (30) grown onto the diamond grit (28) and the substrate (26) so that the diamond grit (28) becomes encased in the CVD diamond (30) and bonded to the surface of the substrate (26).

Claims

1. In a polishing apparatus, a polishing pad conditioning head comprising a substrate, a mono-layer of diamond grit substantially uniformly distributed onto an exposed surface of said substrate, and an outer layer of chemical vapor deposited diamond grown onto the resulting grit covered substrate to encase and bond said diamond grit to said exposed surface, said diamond grit having an average grain size in the range of about 15 microns to about 150 microns and the individual grains of said diamond grit on the exposed surface of said substrate are separated by no less than 1/2 the average grain diameter.

2. The apparatus of claim 1 wherein average grain size of the diamond grit is in the range of about 35 microns to about 70 microns.

3. The apparatus of claim 2 wherein said grit is uniformly disbursed on the surface of said substrate at a density of about 1 to about 30 grains per mm².

4. The apparatus of claim 1 wherein said grit is uniformly distributed on the surface of said substrate at a density of about 0.1 to about 50 grains per mm².

5. The apparatus of claim 1 wherein a layer of smaller diamond grit having an average diameter less than 1 micron is uniformly distributed over said diamond grit and the exposed surface of the substrate after the dispersion of said diamond grit and prior to the chemical vapor deposition of said outer layer of diamond.

6. The apparatus of claim 1 wherein said conditioning head is bonded to a backing layer.

7. The apparatus of claim 1 wherein said diamond grit is distributed over the exposed surface of said substrate in a highly uniform manner.

8. The apparatus of claim 7 wherein an air dispersion step is used to uniformly distribute the diamond grit by dropping the grit at a controlled rate from a fixed height above said exposed surface into a moving air current to disperse the diamond grit in a lateral direction across said exposed surface while moving said source in a direction substantially orthogonal to the direction of the air current.

9. The apparatus of claim 8 wherein said substrate is rotated 90 degrees followed by said air dispersion step and repeating this procedure a plurality of times.

10. In a polishing apparatus, a polishing pad conditioning head comprising a substrate having a first side and a second side, a mono-layer of diamond grit substantially uniformly distributed over said first and second sides, and an outer layer of chemical vapor deposited diamond grown onto the resulting grit covered first and second sides to encase and bond said diamond grit to said sides, said diamond grit having an average grain size in the range of about 15 microns to about 150 microns and the individual grains of said diamond grit on the exposed surface of said substrate are separated by no less than 1/2 the average grain diameter.

11. A method of making a polishing pad conditioning head comprising the steps of:

(a) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of a substrate to achieve an average grit density in the range from about 0.1 to about 50 grains per mm², and the individual grains of said diamond grit on the surface of said substrate are separated by no less than 1/2 the average grain diameter;

(b) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(c) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(d) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(e) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline diamond having a thickness of at least about 10% of the grit size.

12. The method of claim 11 wherein average grain size of the diamond grit is in the range of about 35 microns to about 70 microns.

13. The method of claim 12 wherein said grit is uniformly disbursed on the surface of said substrate at a density of about 1 to about 30 grains per mm².

14. The method of claim 11 wherein a layer of diamond grit having an average diameter less than 1 micron is uniformly distributed over the exposed surface of the substrate after the dispersion of said diamond grit and prior to the chemical vapor deposition of said outer layer of diamond.

15. The apparatus of claim 14 wherein said conditioning head is bonded to a backing layer.

16. The method of claim 14 wherein the resulting disk is bonded to a backing layer.

17. The method of claim 11 wherein an air dispersion step is used to uniformly distribute the diamond grit by dropping the grit at a controlled rate from a fixed height above said exposed surface into a moving air current to disperse the diamond grit in a lateral direction across said exposed surface while moving said source in a direction substantially orthogonal to the direction of the air current.

18. The method of claim 17 wherein said substrate is rotated 90 degrees followed by said air dispersion step and repeating this procedure a plurality of times.

19. The method of claim 11 wherein said exposed surface is initially protected in selected areas by a patterned shield to prevent said diamond grit from reaching the protected areas and to allow said diamond grit to be distributed over the exposed surface of said substrate in a highly uniform manner.

20. A method of making a polishing pad conditioning head comprising the steps of:

(a) placing a substrate into a hot filament chemical vapor deposition reactor;

(b) heating substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(c) chemical vapor depositing an layer of coherent polycrystalline diamond onto an exposed surface of said substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(d) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of said layer of polycrystalline diamond to achieve an average grit density in the range from about 0.1 to about 50 grains per mm² and the individual grains of said diamond grit on the surface of said substrate are separated by no less than 1/2 the average grain diameter;

(e) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(f) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(g) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr; and

(h) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline diamond having a thickness of at least about 10% of the grit size.

21. The method of claim 20 wherein average grain size of the diamond grit is in the range of about 35 microns to about 70 microns.

22. The method of claim 21 wherein said grit is uniformly disbursed on the surface of said substrate at a density of about 1 to about 30 grains per mm².

23. The method of claim 20 wherein a layer of diamond grit having an average diameter less than 1 micron is uniformly distributed over the exposed surface of the substrate after the dispersion of said diamond grit and prior to the chemical vapor deposition of said outer layer of diamond.

24. The method of claim 20 wherein said exposed surface is initially protected in selected areas by a patterned shield to prevent said diamond grit from reaching the protected areas and to allow said diamond grit to be distributed over the exposed surface of said substrate in a highly uniform manner.

25. The method of claim 24 wherein an air dispersion step is used to uniformly distribute the diamond grit by dropping the grit at a controlled rate from a fixed height above said exposed surface into a moving air current to disperse the diamond grit in a lateral direction across said exposed surface while moving said source in a direction substantially orthogonal to the direction of the air current.

26. The method of claim 25 wherein said substrate is rotated 90 degrees followed by said air dispersion step and repeating this procedure a plurality of times.

27. A method of making a polishing pad conditioning head comprising the steps of:

(a) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of a first side of a substrate to achieve an average grit density in the range from about 0.1 to about 50 grains per mm², and the individual grains of said diamond grit on the surface of said substrate are separated by no less than 1/2 the average grain diameter;

(b) placing the resulting substrate into a hot filament chemical vapor deposition reactor;

(c) heating said resulting substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(d) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered side by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(e) cooling said substrate;

(f) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of a second side of said substrate to achieve an average grit density in the range from about 0.1 to about 50 grains per mm², and the individual grains of said diamond grit on the surface of said substrate are separated by no less than 1/2 the average grain diameter;

;

(g) repeating steps (b) through (e); and

(h) recovering a polishing pad conditioning head having both sides of said substrate covered with grit and encased in polycrystalline diamond having a thickness of at least about 10% of the grit size for each side.

28. The method of claim 27 wherein average grain size of the diamond grit is in the range of about 35 microns to about 70 microns.

29. The method of claim 27 wherein said grit is uniformly distributed on the surface of said substrate at a density of about 0.1 to about 50 grains per mm².

30. In a polishing apparatus, a polishing pad conditioning head comprising a substrate, a mono-layer of diamond grit having an average grain size in the range of about 15 microns to about 150 microns substantially uniformly distributed onto an exposed surface of said substrate, a layer of a smaller diamond grit having an average diameter less than 1 micron uniformly distributed over the larger diamond grit, and the exposed surface of the substrate and an outer layer of chemical vapor deposited diamond grown onto the resulting grit covered substrate to encase and bond said diamond grit to said exposed surface.

31. A method of making a polishing pad conditioning head comprising the steps of:

(a) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of a substrate to achieve an average grit density in the range from about 0.1 to about 50 grains per mm² ;

(b) uniformly distributing a layer of a smaller diamond grit having an average diameter less than 1 micron uniformly over the larger diamond grit;

(c) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(d) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(e) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(f) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline diamond having a thickness of at least about 10% of the grit size.

32. A method of making a polishing pad conditioning head comprising the steps of:

(a) initially protecting said exposed surface of said substrate in selected areas by a patterned shield to prevent a diamond grit from reaching the protected areas and to allow said diamond grit to be distributed over the exposed surface of said substrate in a highly uniform manner;

(b) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of a substrate to achieve an average grit density in the range from about 0.1 to about 50 grains per mm² ;

(c) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(d) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(e) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr; and

(f) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline diamond having a thickness of at least about 10% of the grit size.

33. A method of making a polishing pad conditioning head comprising the steps of:

(a) placing a substrate into a hot filament chemical vapor deposition reactor;

(b) heating substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(c) chemical vapor depositing an layer of coherent polycrystalline diamond onto the exposed surface of said substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(d) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of said layer of polycrystalline diamond to achieve an average grit density in the range from about 0.1 to about 50 grains per mm;

(e) uniformly distributing a layer of a smaller diamond grit having an average diameter less than 1 micron uniformly over the larger diamond grit;

(f) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(g) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(h) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr; and

(i) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline.

34. A method of making a polishing pad conditioning head comprising the steps of:

(a) placing a substrate into a hot filament chemical vapor deposition reactor;

(b) heating substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(c) chemical vapor depositing a layer of coherent polycrystalline diamond onto the exposed surface of said substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr;

(d) initially protecting said exposed surface of said substrate in selected areas by a patterned shield to prevent a diamond grit from reaching the protected areas and to allow said diamond grit to be distributed over the exposed surface of said substrate in a highly uniform manner;

(e) uniformly distributing a mono-layer of diamond grit having an average particle diameter in the range of about 15 to about 150 microns over an exposed surface of said layer of polycrystalline diamond to achieve an average grit density in the range from about 0.1 to about 50 grains per mm² ;

(f) placing the resulting grit covered substrate into a hot filament chemical vapor deposition reactor;

(g) heating said grit covered substrate to a deposition temperature of about 600°

to about 1100°

C. by means of a filament electrically charged to a temperature in the range of about 1800°

to 2800°

C.;

(h) chemical vapor depositing an outer layer of coherent polycrystalline diamond onto the exposed surface of the grit covered substrate by passing a gaseous mixture of about 0.1% to about 10% hydrocarbon and the balance hydrogen into said reactor under a pressure of not greater than 100 Torr; and

(i) recovering a polishing pad conditioning head having a grit covered substrate encased in polycrystalline.

35. In a polishing apparatus, a polishing pad conditioning head comprising a substrate having a first side and a second side, a mono-layer of diamond grit having an average grain size in the range of about 15 microns to about 150 microns substantially uniformly distributed over said first and second sides, a layer of a smaller diamond grit having an average diameter less than 1 micron uniformly distributed over the larger diamond grit on the first and second sides, and an outer layer of chemical vapor deposited diamond grown onto the resulting grit covered first and second sides to encase and bond said diamond grit to said first and second sides.