Polishing apparatus

• US 6,558,229 B2
• Filed: 01/17/2001
• Issued: 05/06/2003
• Est. Priority Date: 01/17/2000
• Status: Expired due to Term

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kimura, Norio, Shimizu, Kazuo, Osawa, Hiroyuki, Isobe, Hideji
• Primary Examiner(s): Wilson, Lee
• Assistant Examiner(s): Thomas, David B.
• Application Number:
  US09/760,823
• Publication Number:
  US 20010008827A1
• Time in Patent Office: 839 Days
• Field of Search: 451/5, 451/6, 451/8, 451/9, 451/11, 451/283, 451/285, 451/287, 451/288, 451/289, 451/526
• US Class Current: 451/8
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation
• CPC Class Codes: B24B 49/10 involving electrical means B24B49/02, B24B49/08 take precedence
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing

Abstract

A polishing apparatus is used for polishing a substrate such as a semiconductor wafer, and has a sensor capable of continuously detecting the thickness of an electrically conductive layer. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding and pressing the substrate against the polishing surface to polish the surface of the substrate. A sensor such as an eddy-current sensor is disposed below the polishing surface of the polishing table for measuring the thickness of a conductive layer formed on the surface of the substrate.

Claims

1. A polishing apparatus comprising:

a polishing table having a polishing surface;

a top ring for holding a substrate and pressing a surface of the substrate against said polishing surface to polish said surface of the substrate; and

at least two eddy-current sensors disposed below said polishing surface of said polishing table for measuring the thickness of a conductive layer formed on said surface of the substrate;

wherein the frequencies of high-frequency current supplied to said at least two eddy-current sensors are set to different values from each other.

2. A polishing apparatus according to claim 1, further comprising an optical sensor mounted in said polishing table.

3. A polishing apparatus according to claim 1, wherein said polishing surface comprises a polishing cloth.

4. A polishing apparatus according to claim 1, wherein said polishing surface comprises a fixed abrasive plate.

5. A polishing apparatus comprising:

a polishing table having a polishing surface;

a top ring for holding a substrate and pressing a surface of the substrate against said polishing surface to polish said surface of the substrate; and

at least two eddy-current sensors disposed below said polishing surface of said polishing table for measuring the thickness of a conductive layer formed on the surface of the substrate;

wherein the frequencies of high-frequency current supplied to said at least two eddy-current sensors are variable depending on the polishing process.

6. A polishing apparatus according to claim 5, further comprising an optical sensor mounted in a polishing table.

7. A polishing apparatus according to claim 5, wherein said polishing surface comprises a polishing cloth.

8. A polishing apparatus according to claim 5, wherein said polishing surface comprises a fixed abrasive plate.

9. A polishing method comprising;

polishing a surface of a substrate at a higher polishing rate;

measuring the thickness of a conductive layer formed on the surface of the substrate with two eddy-current sensors disposed below said polishing surface during said polishing;

continuing said polishing until a detected signal from said eddy-current sensors reaches a threshold before an end point of the polishing process; and

polishing the surface of the substrate at a lower polishing rate after the threshold is reached until the end point of the polishing process is reached;

wherein the frequencies of high-frequency current supplied to said at least two eddy current sensors are set to different values from each other.

10. A polishing method according to claim 9, wherein said polishing the surface of the substrate at said higher polishing rate is conducted by a fixed abrasive plate.

11. A polishing method according to claim 9, wherein said polishing the surface of the substrate at said lower polishing rate is conducted by a polishing cloth.

12. A polishing method comprising;

polishing a surface of a substrate at a higher polishing rate;

measuring the thickness of a conductive layer formed on the surface of the substrate with at least two eddy-current sensors disposed below said polishing surface of said polishing table;

continuing said polishing until a detected signal from an eddy-current sensor reaches a threshold before an end point of the polishing process; and

polishing the surface of the substrate at a lower polishing rate after the threshold is reached until the end point of the polishing process is reached;

wherein the frequencies of high-frequency current supplied to said at least two eddy-current sensors are variable depending on the polishing process.

13. A polishing method according to claim 12, wherein said polishing the surface of the substrate at said higher polishing rate is conducted by a fixed abrasive plate.

14. A polishing method according to claim 12, wherein said polishing the surface of the substrate at said lower polishing rate is conducted by a polishing cloth.