Polishing apparatus

• US 20020164932A1
• Filed: 03/14/2001
• Published: 11/07/2002
• Est. Priority Date: 10/24/2000
• Status: Active Grant

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kimura, Norio, Kamimura, Kenji, Tsujimura, Manabu, Okamura, Satoshi, Aizawa, Hideo, Matsuo, Hisanori, Akagi, Makoto, Tokushige, Katsuhiko
• Granted Patent: US 6,939,208 B2
• Time in Patent Office: Days
• US Class Current: 451/56
• CPC Class Codes: B24B 29/005 using brushes
• CPC Class Codes: B24B 53/003 using at least two conditioning tools
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing

Abstract

The present invention relates to a polishing apparatus for polishing a workpiece to be polished, such as a semiconductor wafer, to a flat mirror finish. The polishing apparatus comprises a polishing table having a polishing surface, and a top ring, and the workpiece to be polished is interposed between the polishing table and the top ring and pressed at a predetermined pressure to polish the workpiece. The polishing apparatus comprises at least two dressing units for dressing the polishing surface by being brought into contact with a surface of a polishing cloth.

Claims

1. A polishing apparatus with a polishing table having a polishing surface and a top ring for pressing a workpiece to be polished at a predetermined pressure with interposing said workpiece between said polishing table and said top ring to polish said workpiece, said polishing apparatus comprising:

at least two dressing units for dressing said polishing surface by being brought into contact with a surface of a polishing cloth.

2. A polishing apparatus according to claim 1, wherein dressers in said at least two dressing units comprise different dressing elements, respectively.

3. A polishing apparatus according to claim 1, wherein:

at least one dressing unit is a dressing unit comprising a dresser having a diameter larger than said workpiece to be polished; and

at least one dressing unit is a dressing unit comprising a dresser having a diameter smaller than said workpiece to be polished.

4. A dressing method for dressing a polishing cloth provided in a polishing apparatus, wherein:

initially conditioning said polishing cloth before use in the polishing, by a dressing unit comprising a diamond dresser or an SiC dresser; and

conditioning said polishing cloth between processes of polishing said workpiece to be polished, by a dressing unit comprising a brush dresser.

5. A dressing method for dressing a polishing cloth provided in a polishing apparatus, wherein:

initially conditioning said polishing cloth before use in the polishing, by a dressing unit comprising a diamond dresser or an SiC dresser; and

between processes of polishing said workpiece to be polished, firstly conditioning said polishing cloth by a dressing unit comprising a diamond dresser or an SiC dresser, and then conditioning said polishing cloth by a dressing unit comprising a brush dresser.

6. A dressing method for dressing during polishing of a workpiece to be polished in a polishing apparatus, wherein:

dressing is performed while swinging a dressing unit comprising a dresser having a diameter smaller than said workpiece to be polished; and

after a top ring is withdrawn, dressing is performed by a dressing unit comprising a dresser having a diameter larger than said workpiece to be polished.

7. A polishing apparatus with a polishing table having a polishing surface and a top ring for pressing a workpiece against said polishing surface of said polishing table to polish said workpiece, said polishing apparatus comprising:

a dresser for dressing said polishing surface of said polishing table is further provided, said dresser dressing an area of said polishing surface used for polishing a predetermined position of a surface, to be polished, of said workpiece in accordance with a film thickness to be polished in said predetermined position of said surface to be polished.

8. A polishing apparatus according to claim 7, further comprising:

at least one of a moving mechanism for moving said dresser on said polishing surface of said polishing table, a rotating mechanism for rotating said dresser, and a pressing mechanism for pressing said dresser against said polishing surface of said polishing table; and

a controller for controlling at least one of a speed of movement of said dresser by said moving mechanism, a rotational speed of said dresser by said rotating mechanism, and a pressing load of said dresser by said pressing mechanism, within an area of said polishing surface used for polishing a predetermined position of a surface, to be polished, of said workpiece in accordance with a film thickness to be polished in said predetermined position of said surface to be polished.

9. A polishing apparatus according to claim 7, wherein said dresser has a diameter smaller than said workpiece to be polished.

10. A polishing apparatus according to claim 7, wherein said dresser dresses said polishing surface during polishing.

11. A polishing apparatus according to claim 7, further comprising a cleaning bath for cleaning said dresser.

12. A polishing apparatus according to claim 7, further comprising a film thickness measuring unit for measuring a film thickness of a surface, to be polished, of said workpiece.

13. A polishing apparatus according to claim 7, further comprising a second dresser for dressing substantially the whole area of said polishing surface against which said workpiece to be polished is pressed.

14. A polishing apparatus according to claim 13, wherein when said polishing surface has been locally worn, said second dresser dresses substantially the whole area of said polishing surface.

15. A polishing apparatus according to claim 13, wherein said second dresser has a diameter larger than said workpiece to be polished.

16. A polishing apparatus with a polishing table having a polishing surface and a top ring for pressing a workpiece against said polishing surface of said polishing table to polish said workpiece, said polishing apparatus comprising:

a dressing unit integrally having a first dresser for dressing said polishing surface of said polishing table during polishing of said workpiece to be polished, and a second dresser for dressing said polishing surface of said polishing table when said workpiece to be polished is not polished.