Substrate holding apparatus, polishing apparatus, and polishing method

Abstract

A substrate holding apparatus prevents a substrate from slipping out and allows the substrate to be polished stably. The substrate holding apparatus has a top ring body for holding and pressing a substrate against a polishing surface, and a retainer ring for pressing the polishing surface, the retainer ring being disposed on an outer circumferential portion of the top ring body. The retainer ring comprises a first member made of a magnetic material and a second member having a magnet disposed on a surface thereof which is held in abutment against the first member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a polishing apparatus incorporating a top ring (substrate holding apparatus) according to a first embodiment of the present invention;

FIG. 2 is a vertical cross-sectional view of the top ring in the polishing apparatus shown in FIG. 1;

FIG. 3 is an enlarged fragmentary vertical cross-sectional view of a portion of the top ring shown in FIG. 2 near a retainer ring;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a vertical cross-sectional view of a top ring in a polishing apparatus according to a second embodiment of the present invention; and

FIG. 6 is a plan view of the polishing apparatus according to the second embodiment of the present invention.

Claims

1. A substrate holding apparatus comprising: a top ring body for holding and pressing a substrate against a polishing surface; anda retainer ring for pressing said polishing surface, said retainer ring being disposed on an outer circumferential portion of said top ring body;said retainer ring including: a first member made of a magnetic material; anda second member having a magnet disposed on a surface thereof which is held in abutment against said first member.

2. A substrate holding apparatus according to claim 1, wherein said retainer ring further comprises a mechanism for separating said first member and said second member from each other.

3. A substrate holding apparatus according to claim 1, wherein said first member comprises a piston for pressing said second member against said polishing surface.

4. A substrate holding apparatus according to claim 3, wherein said second member has a cam mechanism including a cam lifter angularly movable for separating said first member from said second member.

5. A substrate holding apparatus according to claim 4, wherein said cam mechanism has a mechanism for limiting an angular movement of said cam lifter within a predetermined range.

6. A substrate holding apparatus according to claim 3, wherein said first member has a cam mechanism including a cam lifter angularly movable for separating said second member from said first member.

7. A substrate holding apparatus according to claim 6, wherein said cam mechanism has a mechanism for limiting said cam lifter to angular movement within a predetermined range.

8. A substrate holding apparatus according to claim 1, wherein said second member comprises a piston for pressing said first member against said polishing surface.

9. A substrate holding apparatus according to claim 8, wherein said first member has a cam mechanism including a cam lifter angularly movable for separating said second member from said first member.

10. A substrate holding apparatus according to claim 9, wherein said cam mechanism has a mechanism for limiting an angular movement of said cam lifter within a predetermined range.

11. A polishing apparatus comprising: a polishing surface;a top ring body for holding and pressing a substrate against said polishing surface to polish the substrate;a retainer ring for pressing said polishing surface, said retainer ring being disposed on an outer circumferential portion of said top ring body;sensors for detecting heights of said retainer ring in at least two positions; anda processor for calculating the gradient of said retainer ring based on the heights of said retainer ring detected by said sensors.

12. A polishing apparatus according to claim 11, wherein said at least two positions are disposed respectively upstream and downstream of said top ring body in a rotating direction of said polishing surface.

13. A polishing apparatus according to claim 11, wherein said sensors comprise displacement sensors, respectively, and said processor performs a moving average process on output signals from said displacement sensors.

14. A polishing apparatus according to claim 11, wherein said retainer ring includes a vertically movable retainer ring portion, and said sensors detect heights of said retainer ring portion in at least two positions.

15. A method of polishing a substrate by holding an outer circumferential portion of the substrate with a retainer ring disposed on an outer circumferential portion of a top ring body, and pressing the substrate against a polishing surface with said top ring body while pressing said retainer ring against said polishing surface, comprising: measuring the gradient of said retainer ring; andgenerating an external alarm signal, stopping polishing the substrate, or changing to a preset polishing condition when the gradient of said retainer ring exceeds a predetermined threshold.

16. A method of polishing a substrate by holding an outer circumferential portion of the substrate with a retainer ring disposed on an outer circumferential portion of a top ring body, and pressing the substrate against a polishing surface with said top ring body while pressing a retainer ring body of said retainer ring against said polishing surface, comprising: measuring the gradient of said retainer ring body; andgenerating an external alarm signal, stopping polishing the substrate, or changing to a preset polishing condition when the gradient of said retainer ring body exceeds a predetermined threshold.