Polishing platen and polishing apparatus

Abstract

The present invention provides a polishing platen which does not require a large force for removing a polishing pad from an upper surface of the polishing platen and can thus make it relatively easy to remove the polishing pad therefrom. The present invention also provides a polishing apparatus having such polishing platen. The polishing platen (12) according to the present invention includes a surface to which a polishing pad is attached. The surface of the polishing platen (12) includes a combination of a first surface (20) and a second surface (21) having a surface roughness which is different from that of the first surface (20).

Description

TECHNICAL FIELD

The present invention relates to a polishing platen for polishing a substrate, such as a semiconductor wafer, and a polishing apparatus using such a polishing platen, and more particularly to a polishing platen having an upper surface from which a polishing pad, attached thereto, can be easily removed, and to a polishing apparatus using such a polishing platen.

BACKGROUND ART

A CMP apparatus (chemical mechanical polishing apparatus) is known as an apparatus for polishing a substrate, e.g., a semiconductor wafer. As shown in FIGS. 1 and 2, a polishing apparatus 10 comprises a polishing platen 12 rotatable about a rotating shaft 11, and a substrate holding head 14 rotatable about a rotating shaft 13. A polishing pad 16 is attached to an upper surface of the polishing platen 12 with an adhesive (e.g., adhesive tape) 15. The substrate holding head 14 is operable to hold and rotate a substrate 18, such as a semiconductor wafer, and press the substrate 18 against a front surface of the polishing pad 16 that is rotated by the polishing platen 12. The substrate 18 is thus polished by relative movement between the substrate 18 rotated by the substrate holding head 14 and the polishing pad 16 rotated by the polishing platen 12. Although not shown in the drawings, an abrasive such as slurry is supplied onto the surface of the polishing pad 16. FIG. 1 shows a side view of the polishing apparatus, and FIG. 2 shows part of the polishing platen.

The polishing apparatus having the above structures has a problem in that, when replacing the polishing pad 16 with new one, a large force is required for removing the polishing pad 16 from the upper surface of the polishing platen 12. This is because the polishing pad 16 is attached to the mirror-finished upper surface of the polishing platen 12 with the adhesive (e.g., adhesive tape) 15. More specifically, a rear surface of the polishing pad 16 sticks firmly to the mirror-finished upper surface of the polishing platen 12 with the adhesive (e.g., adhesive tape) 15. As a result, when an operation of removing the polishing pad 16 is started from an edge portion thereof, a removal force required is relatively small at the beginning, but a larger removal force is gradually required. Accordingly, removal of the polishing pad 16 requires a great deal of labor. As a measure to solve such a problem, a special removal tool is used in order to remove the polishing pad 16, as shown in Japanese laid-open patent publications No. 10-217148 and No. 10-217149.

DISCLOSURE OF INVENTION

The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a polishing platen which does not require a large force for removing a polishing pad from an upper surface of the polishing platen and can thus make it relatively easy to remove the polishing pad therefrom, and to provide a polishing apparatus having such a polishing platen.

In order to achieve the above object, according to one aspect of the present invention, there is provided a polishing platen comprising a surface to which a polishing pad is attached. The surface comprises a combination of a first surface and a second surface having a surface roughness which is different from that of the first surface.

Another aspect of the present invention is to provide a polishing apparatus for polishing a substrate. The apparatus comprises a polishing platen having an upper surface, a polishing pad attached to the upper surface of the polishing platen, the polishing pad having a front surface and a rear surface, and structure for pressing a substrate against the front surface of the polishing pad and polishing the substrate by relative movement between the polishing platen and the substrate. The upper surface of the polishing platen comprises a combination of a first surface and a second surface having a surface roughness which is different from that of the first surface, and the rear surface of the polishing pad is attached to the upper surface of the polishing platen with an adhesive.

Another aspect of the present invention is to provide a polishing apparatus for polishing a substrate. The apparatus comprises a polishing platen having an upper surface, a polishing pad attached to the upper surface of the polishing platen, the polishing pad having a front surface and a rear surface, and structure for pressing a substrate against the front surface of the polishing pad and polishing the substrate by relative movement between the polishing platen and the substrate. The upper surface of the polishing platen comprises a combination of at least one mirror surface portion and at least one rough surface portion, and the rear surface of the polishing pad is attached to the upper surface of the polishing platen with an adhesive.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, the at least one rough surface portion comprises a circular rough surface portion arranged at a center of the upper surface, and the at least one mirror surface portion comprises a belt-shaped mirror surface portion arranged around the circular rough surface portion.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, the at least one mirror surface portion comprises a plurality of belt-shaped mirror surface portions, the at least one rough surface portion comprises a plurality of belt-shaped rough surface portions, and the plurality of mirror surface portions and the plurality of rough surface portions are arranged alternately and concentrically.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, and the at least one mirror surface portion comprises a plurality of mirror surface portions distributed evenly within the at least one rough surface portion.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, and the at least one rough surface portion comprises a plurality of rough surface portions distributed evenly within the at least one mirror surface portion.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, the at least one mirror surface portion comprises a plurality of belt-shaped mirror surface portions extending radially from a center of the upper surface of the polishing platen, and the at least one rough surface portion is provided between the plurality of mirror surface portions.

In a preferable aspect of the present invention, the upper surface of the polishing platen has a circular shape, the at least one rough surface portion comprises a plurality of belt-shaped rough surface portions extending radially from a center of the upper surface of the polishing platen, and the at least one mirror surface portion is provided between the plurality of rough surface portions.

Another aspect of the present invention is to provide a polishing apparatus for polishing a substrate. The apparatus comprises a polishing platen having an upper surface, a polishing pad attached to the upper surface of the polishing platen, the polishing pad having a front surface and a rear surface, and structure for pressing a substrate against the front surface of the polishing pad and polishing the substrate by relative movement between the polishing platen and the substrate. The upper surface of the polishing platen comprises a combination of at least one mirror surface portion and at least one rough surface portion, and the rear surface of the polishing pad is attached to the at least one mirror surface portion with an adhesive.

Another aspect of the present invention is to provide a polishing apparatus for polishing a substrate. The apparatus comprises a polishing platen having an upper surface, a polishing pad attached to the upper surface of the polishing platen, the polishing pad having a front surface and a rear surface, and structure for pressing a substrate against the front surface of the polishing pad and polishing the substrate by relative movement between the polishing platen and the substrate. The upper surface of the polishing platen comprises a mirror surface portion in its entirety, and part of the rear surface of the polishing pad is attached to the mirror surface portion with an adhesive. The part of the rear surface comprises separate areas or a continuous area.

According to one aspect of the present invention described above, because the upper surface of the polishing platen comprises the combination of the first surface and the second surface having a surface roughness which is different from that of the first surface, the removal forces required are different at the first and second surfaces. Thus, the removal force is changed when removing the polishing pad, compared with the case where the upper surface of the polishing platen comprises a uniform surface having the same surface roughness in its entirety, e.g., a mirror-finished surface. Accordingly, the polishing pad can be relatively easily removed from the upper surface of the polishing platen.

According to another aspect of the present invention described above, because the upper surface of the polishing platen comprises the combination of at least one mirror surface portion and at least one rough surface portion, a large force is not required for removing the polishing pad, compared with the case where the upper surface of the polishing platen comprises the mirror-finished surface in its entirety, and hence the polishing pad can be relatively easily removed.

According to another aspect of the present invention described above, because the upper surface of the polishing platen comprises the combination of at least one mirror surface portion and at least one rough surface portion and the rear surface of the polishing pad is attached to the at least one mirror surface portion with the adhesive, the rear surface of the polishing pad contacts the polishing platen at a portion (or portions) corresponding to the at least one mirror surface portion via the adhesive. Thus, a large force is not required for removing the polishing pad, compared with the case where the rear surface of the polishing pad is attached to the mirror-finished upper surface in its entirety of the polishing platen, and hence the polishing pad can be easily removed.

According to another aspect of the present invention described above, because the upper surface of the polishing platen comprises the mirror surface portion in its entirety and part of the rear surface of the polishing pad is attached to the mirror surface portion with the adhesive, a large force is not required for removing the polishing pad, compared with the case where the rear surface of the polishing pad is attached to the mirror-finished upper surface in its entirety of the polishing platen, and hence the polishing pad can be easily removed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view showing an example of schematic structure of a polishing apparatus;

FIG. 2 is a side view showing part of a polishing platen of the polishing apparatus;

FIG. 3 is a plan view showing a structural example of an upper surface of the polishing platen of the polishing apparatus according to the present invention;

FIG. 4 is a plan view showing a structural example of the upper surface of the polishing platen of the polishing apparatus according to the present invention;

FIG. 5 is a plan view showing a structural example of the upper surface of the polishing platen of the polishing apparatus according to the present invention;

FIG. 6 is a plan view showing a structural example of the upper surface of the polishing platen of the polishing apparatus according to the present invention;

FIG. 7 is a plan view showing a structural example of a rear surface of a polishing pad of the polishing apparatus according to the present invention;

FIG. 8 is a plan view showing a structural example of the rear surface of the polishing pad of the polishing apparatus according to the present invention;

FIG. 9 is a plan view showing a structural example of the rear surface of the polishing pad of the polishing apparatus according to the present invention; and

FIG. 10 is a plan view showing a structural example of the rear surface of the polishing pad of the polishing apparatus according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a plan view showing a structural example of an upper surface of a polishing platen of a polishing apparatus according to the present invention. As shown in the drawing, an upper surface of a polishing platen 12 comprises a circular rough surface portion 20 which is a grained surface at a center thereof, and a belt-shaped mirror surface portion 21 which is a mirror-finished surface arranged around the rough surface portion 20.

A rear surface of a polishing pad 16 is attached to the upper surface of the polishing platen 12 with an adhesive (e.g., adhesive tape) 15. With this structure, the belt-shaped mirror surface portion 21 provides a strong adhesive area, but the circular rough surface portion 20 provides a weak adhesive area. Thus, when an operation of removing the polishing pad 16 is started from its edge portion, i.e., a peripheral portion of the mirror surface portion 21, a removal force required is small at the beginning, but gradually becomes, large. However, after the circumferentially extending annular mirror surface portion 21 is separated from the polishing platen 12, the rough surface portion 20, requiring a small removal force, is to be separated. Therefore, the removal force required becomes small, and hence the polishing pad 16 can be easily removed from the polishing platen 12.

FIG. 4 is a plan view showing another example of the upper surface of the polishing platen of the polishing apparatus according to the present invention. As shown in the drawing, the upper surface of the polishing platen 12 comprises a circular rough surface portion 26 which is a grained surface at the center thereof, a belt-shaped mirror surface portion 25 which is a mirror-finished surface arranged around the rough surface portion 26, a belt-shaped rough surface portion 24 which is a grained surface arranged around the mirror surface portion 25, and a belt-shaped mirror surface portion 23 which is a mirror-finished surface arranged around the rough surface portion 24. These belt-shaped portions 23, 24 and 25 are arranged alternately and concentrically.

The mirror surface portions 25 and 23 and the rough surface portion 24, which are arranged alternately and concentrically, can provide the following effects. When an operation of removing the polishing pad 16 is started from its edge portion, i.e., the mirror surface portion 23, a removal force required is small at the beginning, but gradually becomes large. After the circumferentially extending mirror surface portion 23 is separated from the polishing platen 12, the rough surface portion 24, requiring a small removal force, is separated. Subsequently, the mirror surface portion 25, requiring a large removal force, is separated, and then the rough surface portion 26, requiring a small removal force, is separated. In this manner, the small and large removal forces are alternately required. Accordingly, the polishing pad 16 can be easily removed from the polishing platen 12.

FIG. 5 is a plan view showing another example of an upper surface of the polishing platen of the polishing apparatus according to the present invention. As shown in the drawing, the upper surface of the polishing platen 12 comprises a rough surface portion 27 which is a grained rough surface covering the upper surface of the polishing platen 12 in its entirety, and circular mirror surface portions 28 evenly distributed over the rough surface portion 27. With this arrangement, the mirror surface portions 28, requiring a large removal force, are scattered within the rough surface portion 27 requiring a small removal force. Thus, the portions, requiring the large and small removal forces, are distributed. As a result, compared with structures having a mirror-finished upper surface in its entirety, the polishing pad 16 can be easily removed from the polishing platen 12. Although the mirror surface portions 28 are scattered within the rough surface portion 27 in this example, rough surface portions may be evenly scattered within a mirror surface portion. Further, it should be noted that the shape of the scattered portions is not limited to circle.

FIG. 6 is a plan view showing another example of an upper surface of the polishing platen of the polishing apparatus according to the present invention. As shown in the drawing, the upper surface of the polishing platen 12 comprises a rough surface portion 29 which is a grained rough surface covering the upper surface of the polishing platen 12 in its entirety, and a plurality of (eight in the drawing) belt-shaped mirror surface portions 30 arranged in the rough surface portion 29 and radially extending from the center of the upper surface of the polishing platen 12. In this example also, the rough surface portion 29, requiring a small removal force, is arranged between the mirror surface portions 30 requiring a large removal force. Accordingly, compared with the structure having an entire mirror-finished surface, the polishing pad 16 can be easily removed. Alternatively, a plurality of radially extending rough surface portions may be provided such that a mirror surface portion is arranged between the rough surface portions.

As shown in FIG. 7, an annular adhesive tape (adhesive double coated tape) 31 may be attached to a rear surface 16a of the polishing pad 16 at a position corresponding to the mirror surface portion 21 of the polishing platen 12 shown in FIG. 3, so that the polishing pad 16 is attached to the mirror surface portion 21 via the adhesive tape 31. Similarly, as shown in FIG. 8, annular adhesive tapes (adhesive double coated tapes) 32 and 33 may be attached concentrically to the rear surface 16a of the polishing pad 16 at positions corresponding to the mirror surface portions 23 and 25 of the polishing platen 12 shown in FIG. 4, so that the polishing pad 16 is attached to the mirror surface portions 23 and 25 via the adhesive tapes 32 and 33.

Further, as shown in FIG. 9, evenly scattered adhesive tapes (adhesive double coated tapes) 34 may be attached to the rear surface 16a of the polishing pad 16 at positions corresponding to the evenly scattered mirror surface portions 28 of the polishing platen 12 shown in FIG. 5, so that the polishing pad 16 is attached to the mirror surface portions 28 via the adhesive tapes 34. Similarly, as shown in FIG. 10, radially extending adhesive tapes (adhesive double coated tapes) 35 may be attached to the rear surface 16a of the polishing pad 16 at positions corresponding to the radially extending mirror surface portions 30 of the polishing platen 12 shown in FIG. 6, so that the polishing pad 16 is attached to the mirror surface portions 30 via the adhesive tapes 35.

In this manner, the rear surface 16a of the polishing pad 16 can be attached using the adhesive tape(s) to the mirror surface portion(s) of the upper surface of the polishing platen 12. In this case also, a large force is not required for removing the polishing pad 16, compared with the case where the rear surface 16a of the polishing pad 16 is attached to the mirror-finished upper surface in its entirety of the polishing platen 12, and hence the polishing pad 16 can be easily removed.

The entire upper surface of the polishing platen 12 may be mirror-finished to form a mirror surface portion, and the adhesive tape(s) shown in FIGS. 7 to 10 may be attached to the rear surface 16a of the polishing pad 16. In this case also, only part of the rear surface 16a of the polishing pad 16 is attached to the upper surface of the polishing platen 12 via the adhesive tape(s). Thus, a large force is not required for removing the polishing pad 16, compared with the case where the rear surface 16a of the polishing pad 16 is attached to the mirror-finished upper surface in its entirety of the polishing platen 12, and hence the polishing pad 16 can be easily removed.

Next, an example of a method of forming the mirror-surface portion and the rough surface portion on the upper surface of the polishing platen 12 will be described. First, the upper surface in its entirety of the polishing platen 12 is mirror-finished by, for example, lapping. Then, the mirror-finished upper surface of the polishing platen 12 is covered with a mask having an opening (or openings) corresponding to the rough surface portion(s). In this state, blasting, such as blow of alumina beads (FUJI RANDOM A80), is applied evenly to the opening(s) with blow pressure of 0.5 MPa to thereby form the rough surface portion(s) of a predetermined shape within the mirror surface portion, as shown in FIGS. 3 through 6. It is not necessary to use lapping for forming the mirror surface portion. For example, the upper surface of the polishing platen 12 may be subjected to grinding to have a surface roughness of about 6.3 S. Thereafter, blasting may be applied to form the rough surface portion within the ground surface. What is essential is to provide the upper surface of the polishing platen 12 comprising a combination of a first surface having a small surface roughness and a second surface having a large surface roughness so that a small force is required for removing the polishing pad 16 from the upper surface of the polishing platen 12.

In the polishing apparatus according to the foregoing embodiments, the upper surface of the polishing platen 12 has a circular shape and is rotatable about the rotating shaft 11. However, the polishing apparatus is not limited to such structures so long as the apparatus can provide relative movement between the polishing platen and the substrate while pressing the substrate against the polishing pad attached to the upper surface of the polishing platen to thereby polish the substrate.

Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of claims for patent, and the scope of the technical concept described in the specification and drawings.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a polishing platen having an upper surface from which a polishing pad, attached thereto, can be easily removed, and to a polishing apparatus using such a polishing platen.

Claims

1. A polishing platen, comprising: a surface to which a polishing pad is attached, said surface comprising a combination of a first surface and a second surface having a surface roughness which is different from that of said first surface.

2. A polishing apparatus for polishing a substrate, said apparatus comprising: a polishing platen having an upper surface;a polishing pad attached to said upper surface of said polishing platen, said polishing pad having a front surface and a rear surface; andstructure for pressing a substrate against said front surface of said polishing pad and polishing the substrate by relative movement between said polishing platen and the substrate,wherein said upper surface of said polishing platen comprises a combination of a first surface and a second surface having a surface roughness which is different from that of said first surface, andsaid rear surface of said polishing pad is attached to said upper surface of said polishing platen with an adhesive.

3. A polishing apparatus for polishing a substrate, said apparatus comprising: a polishing platen having an upper surface;a polishing pad attached to said upper surface of said polishing platen, said polishing pad having a front surface and a rear surface; andstructure for pressing a substrate against said front surface of said polishing pad and polishing the substrate by relative movement between said polishing platen and the substrate,wherein said upper surface of said polishing platen comprises a combination of at least one mirror surface portion and at least one rough surface portion, andsaid rear surface of said polishing pad is attached to said upper surface of said polishing platen with an adhesive.

4. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape;said at least one rough surface portion comprises a circular rough surface portion arranged at a center of said upper surface; andsaid at least one mirror surface portion comprises a belt-shaped mirror surface portion arranged around said circular rough surface portion.

5. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape;said at least one mirror surface portion comprises a plurality of belt-shaped mirror surface portions;said at least one rough surface portion comprises a plurality of belt-shaped rough surface portions; andsaid plurality of mirror surface portions and said plurality of rough surface portions are arranged alternately and concentrically.

6. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape; andsaid at least one mirror surface portion comprises a plurality of mirror surface portions distributed evenly within said at least one rough surface portion.

7. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape; andsaid at least one rough surface portion comprises a plurality of rough surface portions distributed evenly within said at least one mirror surface portion.

8. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape;said at least one mirror surface portion comprises a plurality of belt-shaped mirror surface portions extending radially from a center of said upper surface of said polishing platen; andsaid at least one rough surface portion is provided between said plurality of mirror surface portions.

9. The polishing apparatus according to claim 3, wherein: said upper surface of said polishing platen has a circular shape;said at least one rough surface portion comprises a plurality of belt-shaped rough surface portions extending radially from a center of said upper surface of said polishing platen; andsaid at least one mirror surface portion is provided between said plurality of rough surface portions.

10. A polishing apparatus for polishing a substrate, said apparatus comprising: a polishing platen having an upper surface;a polishing pad attached to said upper surface of said polishing platen, said polishing pad having a front surface and a rear surface; andstructure for pressing a substrate against said front surface of said polishing pad and polishing the substrate by relative movement between said polishing platen and the substrate,wherein said upper surface of said polishing platen comprises a combination of at least one mirror surface portion and at least one rough surface portion, andsaid rear surface of said polishing pad is attached to said at least one mirror surface portion with an adhesive.

11. (canceled)