Abrading plate and polishing method using the same

• US 6,413,149 B1
• Filed: 12/23/1999
• Issued: 07/02/2002
• Est. Priority Date: 04/28/1998
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Hirokawa, Kazuto, Wada, Yutaka, Matsuo, Hisanori, Hiyama, Hirokuni
• Primary Examiner(s): Hail, III, Joseph J.
• Assistant Examiner(s): Shakeri, Hadi
• Application Number:
  US09/446,764
• Time in Patent Office: 922 Days
• Field of Search: 451/41, 451/285, 451/587, 451/59, 451/63, 451/533, 451/548, 451/526, 451/540, 512/95, 512/93, 512/98
• US Class Current: 451/41
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 37/245 Pads with fixed abrasives
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: B24D 3/32 for porous or cellular structure
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]

Abstract

The present invention provides an abrading plate having self-stopping capability such that when an object, such as a semiconductor wafer having a device structure that includes raised regions and depressed regions fabricated on the surface, is being polished, the raised regions are removed and polishing stops automatically. A method of using the abrading plate is also provided.

The present invention relates to an abrading plate that produces a flat and mirror polished surface on an object with an abrading plate comprised by abrasive particles having a chemical purity of not less than 90% and a particle size of not more than two micrometers; a binder material; and a given volume of porosity, wherein a ratio of the abrasive particles and the binder material is not less than 1:0.5 by volume, and proportions of abrasive particles, a binder material and porosity are, respectively, not less than 10%, not more than 60% and 10˜40 by volume.

The method is provided for polishing an object having a device structure that includes raised regions and depressed regions fabricated on the surface according to the steps of polishing the surface for a given duration with a liquid not containing abrasive particles so as to eliminate the raised regions to obtain a flat surface, and performing additional surface removal by supplying abrasive particles to the polishing interface to remove surface material uniformly from the entire surface.

Claims

1. An abrading plate for polishing an object to produce a flat and mirror surface thereon, said abrading plate comprising:

abrasive particles having a particle size of less than two micrometers, a chemical purity of more than 90%, and a Na concentration of below 100 ppm;

a binder material; and

a porosity;

wherein a ratio of said abrasive particles and said binder material is 1;

x, where x is not less than 0.5 by volume, and said abrasive particles, said binder material and said porosity are in a proportion such that said abrasive particles are not less than 10% by volume, said binder material is not more than 60% by volume, and said porosity is 10˜

40% by volume.

2. An abrading plate according to claim 1, wherein said proportion is such that said abrasive particles are 10-60% by volume, said binder material is 30-60% by volume and said porosity is 10˜

40% by volume.

3. An abrading plate for polishing an object having a raised and depressed pattern thereon to produce a flat and mirror polished surface, said abrading plate comprising abrasive particles having a chemical purity of more than 90% and a Na concentration of below 100 ppm;

wherein said abrading plate comprises said abrasive particles, a binder material, and a porosity.

4. A method for polishing an object having a raised and depressed pattern thereon to produce a flat and mirror polished surface, wherein said method is comprised by using an abrading plate, which comprises abrasive particles having a chemical purity of more than 90% and a Na concentration of below 100 ppm, a binder material, and a porosity.

5. A method according to claim 4, wherein a second stage polishing is further carried out by using a polishing cloth after said first stage polishing using said abrading plate is finished.

6. A method according to claim 4, wherein a second stage polishing is further carried out by using a second abrading plate after said first stage polishing using said abrading plate is finished.

7. A method according to claim 4, wherein said polishing is carried out after dressing an abrading surface of said abrading plate so as to produce a micro-rough surface structure thereon.

8. A method according to claim 4, further comprising:

dressing an abrading surface of said abrading plate so as to produce a finely roughened surface structure thereon;

removing released particles adhering to said surface; and

polishing said object.

9. A method according to claim 4, wherein said polishing is carried out while concurrently dressing an abrading surface of said abrading plate so as to produce a finely roughened surface structure thereon.

10. A method according to claim 4, wherein said polishing is carried out while supplying a liquid not containing abrasive particles so as to generate free abrasive particles released from said abrading surface of said abrading plate.

11. A method according to claim 10, wherein said liquid not containing abrasive particles is water or a chemical solution.

12. A method according to claim 4, wherein said polishing is carried out by using said abrading plate comprised of abrasive particles having not more than 0.5 μ

m particle size, a binder and a porosity.

13. A method according to claim 4, wherein said abrading plate comprises abrasive particles having a particle size of less than two micrometers and a chemical purity of more than 90%;

a binder material; and

a porosity;

wherein a ratio of said abrasive particles and said binder material is 1;

x, where x is not less than 0.5 by volume, and said abrasive particles, said binder material and said porosity are in a proportion such that said abrasive particles are not less than 10% by volume, said binder material is not more than 60% by volume, and said porosity is 10˜

40% by volume.

14. A method for polishing a semiconductor wafer having a raised and depressed pattern thereon to produce a flat and mirror polished surface, said method comprising:

polishing said semiconductor wafer by using an abrading plate having abrasive particles, binder material and porosity, a proportion of said abrasive particles, binder material and porosity being such that said abrasive particles are 10%-60% by volume, said binder material is 30-60% by volume, and said porosity is 10˜

40% by volume,

wherein said abrading plate has a self-stopping function which stops or reduces a removal rate of continued polishing after said raised pattern is flattened and the surface has become level.

15. A method for polishing a semiconductor wafer having a raised and depressed pattern thereon to produce a flat and mirror polished surface, said method comprising:

polishing said semiconductor wafer by using an abrading plate having abrasive particles, binder material and porosity, a proportion of said abrasive particles, binder material and porosity being such that said abrasive particles are 10-60% by volume, said binder material is 30-60% by volume, and said porosity is 10˜

40% by volume;

wherein said abrasive particles have a Na concentration of below 100 ppm.

16. A polishing apparatus having an abrading plate for polishing an object to produce a flat and mirror surface thereon, said abrading plate comprising:

abrasive particles having a particle size of less than two micrometers, a chemical purity of more than 90%, and a Na concentration of below 100 ppm;

a binder material; and

a porosity;

wherein a ratio of said abrasive particles and said binder materials is 1;

x, where x is not less than 0.5 by volume, and a proportion of said abrasive particles, said binder material and said porosity is such that said abrasive particles are not less than 10% by volume, said binder material is not more than 60% by volume, and said porosity 10˜

40% by volume.

17. A polishing apparatus having an abrading plate for polishing an object having raised and depressed patterns thereon to produce a flat and mirror polished surface, said abrading plate comprising abrasive particles having a chemical purity of more than 90% and a Na concentration of below 100 ppm;

wherein said abrading plate comprises said abrasive particles, binder material, and a porosity.

18. A polishing apparatus according to claim 17, wherein said polishing apparatus further comprises a dresser for dressing an abrading surface of said abrading plate so as to produce a finely roughened surface structure thereon.

19. A polishing apparatus according to claim 18, wherein said dresser comprises a diamond dresser.

20. A polishing apparatus according to claim 18, wherein said dresser comprises a brush.

21. A polishing apparatus according to claim 18, wherein said dresser comprises a water jet.

22. An abrading plate for polishing an object having a raised and depressed pattern thereon, said abrading plate comprising:

abrasive particles;

a binder; and

a porosity;

wherein a proportion by volume of said abrasive particles, binder, and porosity is such that said abrasive particles are 10-60% by volume, said binder material is 30-60% by volume, and said porosity is 10˜

40% by volume and said abrading plate having a self-stopping function which stops or reduces a removal rate of continued polishing after said raised patterns are flattened and the surface has become level.