POLISHING PAD AND CHEMICAL MECHANICAL POLISHING APPARATUS

Abstract

A polishing pad and a chemical mechanical polishing apparatus are provided. The polishing pad includes: a central portion, designed with a central recess; and a peripheral portion surrounding the central portion, and designed with at least one peripheral recess. The at least one peripheral recess is disposed along an annulus contour. A lower part of the peripheral recess is greater than an upper part of the peripheral recess in terms of diameter area, and is different from the upper part in shape.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 112149436, filed on Dec. 19, 2023. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

This invention relates to semiconductor processing equipment and components thereof, particularly a chemical mechanical polishing apparatus and a polishing pad used by the same.

Description of Related Art

Semiconductor manufacturing processes often use chemical mechanical polishing (CMP) to perform planarization operations. During chemical mechanical polishing, in addition to the reaction between the polishing liquid and the wafer, the carrier and the wafer suction chuck rotate so that the polishing liquid's suspended particles pass through the polishing pad's support to polish the wafer. The polishing pad conditioner contacts the rotating polishing pad to scrape off the grinding residue and maintain the roughness of the polishing pad.

Compared with the peripheral portion of the polishing pad, the central portion of the polishing pad wears out at a higher rate by the polishing pad conditioner. Therefore, at the later stage of the polishing pad's service life, the polishing pad will form a concave structure from the periphery to the center, which makes the recesses in the peripheral portion of the polishing pad less likely to retain polishing liquid, resulting in a lower polishing rate in the peripheral portion of the polishing pad than in the central portion of the polishing pad. In other words, at the later stage of the service life of the polishing pad, there is an issue of reduced polishing uniformity.

SUMMARY

This disclosure provides a polishing pad and a chemical mechanical polishing apparatus using the polishing pad. Through the unique recess design on the polishing pad, sufficient polishing uniformity is maintained at the later stage of the service life of the polishing pad.

In an aspect of this disclosure, a polishing pad is provided for a chemical mechanical polishing apparatus and includes: a central portion provided with a central recess; and an peripheral portion surrounding the central portion provided with at least one peripheral recess, wherein the at least one peripheral recess is arranged along an annulus contour, the lower part of the at least one peripheral recess is larger than the upper part of the at least one peripheral recess in diameter area, and is different from the upper part of the at least one peripheral recess in shape.

In another aspect of this disclosure, a chemical mechanical polishing apparatus is provided, including: a carrier; a polishing pad placed on the carrier which includes a central portion and a peripheral portion surrounding the central portion, wherein the central portion is provided with a central recess, the peripheral portion is provided with at least one peripheral recess, the at least one peripheral recess is arranged along an annulus contour, and the lower part of the at least one peripheral recess has a diameter area and a capacity larger than the upper part of the at least one peripheral recess and are different from the upper part of the at least one peripheral recess in shape; a wafer suction chuck configured to attach and control the wafer so that the wafer contacts the polishing pad; and a polishing liquid supply device is configured to provide polishing liquid to the surface of the polishing pad from above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a three-dimensional schematic diagram of a chemical mechanical polishing apparatus according to some embodiments.

According to some embodiments, FIG. 2A, FIG. 4A, and FIG. 6A are top views of a polishing pad at an early stage of service life.

FIG. 2B is a schematic cross-sectional view along line A-A′ of FIG. 2A.

FIG. 3A is a schematic top view of the polishing pad shown in FIG. 2A at the later stage of the service life of the polishing pad.

FIG. 3B is a schematic cross-sectional view along line A-A′ of FIG. 3A.

FIG. 4B is a schematic cross-sectional view along line A-A′ of FIG. 4A.

FIG. 5A is a schematic top view of the polishing pad shown in FIG. 4A at the later stage of the service life of the polishing pad.

FIG. 5B is a schematic cross-sectional view along line A-A′ of FIG. 5A.

FIG. 6B is a schematic cross-sectional view along line A-A′ of FIG. 6A.

FIG. 7A is a schematic top view of the polishing pad shown in FIG. 6A at the later stage of the service life of the polishing pad.

FIG. 7B is a schematic cross-sectional view along line A-A′ of FIG. 7A.

FIG. 8A is a schematic top view of a polishing pad at a later stage of the service life of the polishing pad according to some embodiments.

FIG. 8B is a schematic cross-sectional view along line A-A′ of FIG. 8A.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

The embodiments of this disclosure provide a solution to the insufficiency of polishing uniformity at the later stage of the service life of a polishing pad. Specifically, through the unique recess design of the polishing pad, sufficient polishing uniformity is maintained at the later stage of the service life of the polishing pad.

FIG. 1 is a three-dimensional schematic diagram of a chemical mechanical polishing apparatus 10 according to some embodiments of this disclosure.

Referring to FIG. 1, the chemical mechanical polishing apparatus 10 may include a carrier 100, a polishing pad 102 positioned on a carrier 100, a wafer suction chuck 104 for attaching and controlling a wafer W, a polishing liquid supply device 106 to provide a certain amount of polishing liquid SL, and a polishing pad conditioner 108 to condition the surface of the polishing pad 102.

During the chemical mechanical polishing operation, the polishing liquid supply device 106 provides the polishing liquid SL to the surface of the polishing pad 102, causing partial polishing liquid SL to be temporarily stored in the recesses on the surface of the polishing pad 102. In addition, the wafer suction chuck 104 attaches and presses the wafer W onto the polishing pad 102. The wafer suction chuck 104, which attaches the wafer W, and the carrier 100, which carries the polishing pad 102, rotate relative to each other. At this time, the polishing liquid SL in the recesses of the polishing pad 102 is released onto the surface of the polishing pad 102. The chemical additives in the polishing liquid SL react with the wafer W to remove the target material on the surface of the wafer W. In addition, the suspended particles in the polishing liquid SL are supported by the polishing pad 102 to polish the wafer W. Through this chemical reaction and physical polishing process, the surface of the wafer W is planarized.

Meanwhile, during the chemical mechanical polishing process, the polishing pad conditioner 108 contacts the polishing pad 102 from above, removes polishing residues through the rotating disc (such as a diamond disc), and conditions the surface of the polishing pad 102. More specifically, the disc of the polishing pad conditioner 108 wears out the polishing pad 102 for conditioning the polishing pad 102 and maintaining the roughness of the polishing pad 102. Hence, after being conditioned by the polishing pad conditioner 108, the thickness of polishing pad 102 is reduced. However, in reality, the thickness reduction of the polishing pad 102 is uneven.

In the polishing pad 102, the closer to the center, the radius is smaller, and the closer to the edge, the radius is larger. In other words, comparatively, in the polishing pad 102, the portion closer to the center has higher revolutions per minute (RPM) and contacts the polishing pad conditioner 108 more often. As a result, the central portion of the polishing pad 102 is more worn by the polishing pad conditioner 108. Therefore, the polishing pad 102 forms a gradually concave structure from the periphery toward the center at the later stage of the service life. In the meantime, the polishing liquid SL held in the peripheral recesses of the polishing pad 102 flows toward the center. The area with more polishing liquid SL has better grinding efficiency; the area with less polishing liquid SL has worse grinding efficiency. To avoid the issue that the peripheral portion of the polishing pad 102 lacks enough polishing liquid SL, causing the polishing rate to be lower than the central portion at the end of the service life, the polishing pad 102 has different recess designs in the peripheral portion, compared to the central portion.

FIG. 2A is a schematic top view of the polishing pad 102 at the beginning of the service life of the polishing pad 102 according to some embodiments. FIG. 2B is a schematic cross-sectional view along line A-A′ of FIG. 2A.

Referring to FIG. 2A, the polishing pad 102 may be divided into a central portion CR and a peripheral portion PR surrounding CR. In the central portion CR, the polishing pad 102 has a plurality of central recesses R_C arranged sequentially from the center of the polishing pad 102 outward. In some embodiments, these central recesses R_C are annulus recesses extending continuously around the center of the polishing pad 102. As a practical example, the central recesses R_C are concentric annulus recesses. In other embodiments, the central recesses R_C may also be cross recesses or recesses of other shapes. It is understood that a person with ordinary knowledge of the art are able to adjust the shapes and numbers of the central recesses R_C according to actual needs, and this disclosure is not limited thereto.

As shown in FIG. 2B, each central recess R_C have a consistent opening width from top to bottom. Therefore, each central recess R_C exposes an opening of approximately the same size at each stage of the service life of the polishing pad 102, thereby providing substantially the same amount of the polishing liquid SL onto the surface of the polishing pad 102. In other words, at each stage of the service life of the polishing pad 102, the central portion CR of the polishing pad 102 has relatively the same polishing rate.

On the other hand, as shown in FIG. 2A, the polishing pad 102 has a plurality of peripheral recesses R_P separated from each other in the peripheral portion PR. These peripheral recesses R_P are arranged along one or more annulus contours at the periphery of the central recesses R_C in the central portion CR. As a practical example, the polishing pad 102 has two peripheral recesses R_P arranged along concentric annulus contours in the peripheral portion PR at the periphery of the central recesses R_C. It is understood that a person with ordinary knowledge of the art is able to adjust the number of recesses of the peripheral recesses R_P according to the size of the peripheral portion PR, and this disclosure is not limited thereto.

As shown in FIG. 2B, the upper part of each peripheral recess R_P is a straight hole H1, and the lower part of each peripheral recess R_P is a U-shaped hole H2. As a combination of holes H1 and H2, each peripheral recess R_P has a shape similar to a curved umbrella handle. In the early period of the service life of the polishing pad 102, only the upper straight hole H1 in each peripheral recess R_P is exposed.

In some embodiments, the diameter width of each peripheral recess R_P in the peripheral portion PR (that is, the opening width W_P1 of the straight hole H1 and the opening width W_P2 of each section of the U-shaped hole H2) is approximately equal to the diameter width W_C of each central recess R_C. In other embodiments, the opening width W_P1/W_P2 of each peripheral recess R_P in the peripheral portion PR is smaller than the opening width W_C of each central recess R_C in the central portion CR.

Furthermore, according to some embodiments, each peripheral recess R_P in the peripheral portion PR of the polishing pad 102 is slanted. Specifically, the opening of each peripheral recess R_P is slanted from the vertical direction toward the central axis of the polishing pad 102. In other words, each peripheral recess R_P is similar to tilting toward the center of the polishing pad 102. This design helps to utilize centrifugal force to further maintain the polishing liquid SL in the peripheral portion PR at the later stage of the service life of the polishing pad 102, thereby further improving the polishing uniformity at the later stage of the polishing pad 102. On the other hand, the central recesses R_C in the central portion CR of the polishing pad 102 have no slanted design. In other words, the central recesses R_C may extend into the polishing pad 102 along a vertical direction.

FIG. 3A is a schematic top view of the polishing pad 102 at the later stage of the service life of the polishing pad 102. FIG. 3B is a schematic cross-sectional view along line A-A′ of FIG. 3A.

After the polishing pad 102 is used for a while, the surface gradually wears away, so the upper straight holes H1 of each peripheral recess R_P are removed. The U-shaped holes H2 of each peripheral recess R_P are now exposed. As shown in FIG. 3A and FIG. 3B, each U-shaped hole H2 is exposed to the peripheral portion PR of the polishing pad 102 with two openings. Compared with the early stage of the service life of the polishing pad 102, the peripheral portion PR has twice the number of openings and areas than that at the later stage of the service life of the polishing pad 102. In some embodiments, as shown in FIG. 3A, the openings of the U-shaped holes H2 are arranged in a radial manner.

Compared with the recesses that are straight holes from the top to the bottom, the lower part of the peripheral recesses R_P is designed to be U-shaped and has a larger capacity to accommodate more of the polishing liquid SL, and has double the cross-sectional area. Therefore, at the later stage of the service life of the polishing pad 102 (when the straight holes H1 are worn away and the U-shaped holes H2 are exposed), sufficient polishing liquid SL is still provided at the peripheral portion PR of the polishing pad 102. Therefore, it is possible to avoid the phenomenon of the peripheral portion PR of the polishing pad 102 having a significantly lower polishing rate than the central portion CR due to a lack of sufficient polishing liquid SL at the later stage of the service life of the polishing pad 102. As a result, the issue of uneven polishing that occurs at the later stage of the polishing pad 102 is resolved.

In the embodiment of the polishing pad 102 where the diameter width of each peripheral recess R_P (that is, the diameter width W_P1 of the straight hole H1 and the diameter width W_P2 of each section of the U-shaped hole H2) is approximately equal to the diameter width W_C of each central recess R_C in the central portion CR, the polishing rate of the central portion CR and the peripheral portion PR in the early stage of the service life of the polishing pad 102 are approximately the same. Also, the peripheral portion PR has an opening area of relatively twice as much in the later stage of the service life of the polishing pad 102. Therefore, in a situation where there is high polishing uniformity during the early stage of the service life, the issue of uneven polishing at the later stage of the service life is prevented.

On the other hand, after the central recesses R_C in the central portion CR of the polishing pad 102 is conditioned, the lower portion remains, and a single opening is maintained, respectively. By increasing the number of the polishing pad 102's peripheral recesses R_P in the peripheral portion PR while maintaining the diameter area of the central recesses R_C in the central portion CR at the later stage of the service life of the polishing pad 102, the grinding uniformity is improved as the polishing liquid is distributed more evenly with non-uniform design to compensate for the uneven polishing as much as possible.

FIG. 4A is a schematic top view of the polishing pad 402 at the beginning of the service life of the polishing pad 402 according to some embodiments. FIG. 4B is a schematic cross-sectional view along line A-A′ of FIG. 4A. FIG. 5A is a schematic top view of the polishing pad 402 at the later stage of the service life of the polishing pad 402. FIG. 5B is a schematic cross-sectional view along line A-A′ of FIG. 5A.

The polishing pad 402 is similar to the polishing pad 102 described in FIG. 2A, FIG. 2B, FIG. 3A, and FIG. 3B, except that the recess design of the peripheral portion PR is different. As shown in FIG. 4A, the peripheral portion PR of the polishing pad 402 is provided with a peripheral recess R_P1 that extends continuously along the annulus contour. As a practical example, peripheral recess R_P1 of the polishing pad 402 extends continuously in the peripheral portion PR along a concentric annulus contour. A person with ordinary knowledge of the art may adjust the number of recesses of the peripheral recess R_P1 according to the size of the peripheral portion PR, and this disclosure is not limited thereto.

As shown in FIG. 4B, the peripheral recess R_P1 includes an upper straight recess T1 and a lower U-shaped recess T2. Different from the straight hole H1 and the U-shaped hole H2, as shown in FIG. 2B, the straight recess T1 and the U-shaped recess T2 extend continuously along the annulus contour. In the early period of the service life of the polishing pad 402 (as shown in FIG. 4A and FIG. 4B), each peripheral recess R_P1 is only exposed by the upper straight recess T1. After the polishing pad 402 is used for a while, the surface gradually wears down so that the upper straight recess T1 of each peripheral recess R_P1 is removed. At this time, as shown in FIG. 5A and FIG. 5B, the U-shaped recesses T2 of each peripheral recess R_P1 are exposed with double annulus openings. Compared with a recess that is a straight hole/recess from top to bottom, the lower part of the peripheral recess R_P1 accommodates more of the polishing liquid SL due to the design being U-shaped and approximately double in the cross-section area. Hence, at the later stage of the service life of the polishing pad 402, the polishing liquid SL is still sufficient at the peripheral portion PR of the polishing pad 402. This scheme prevents the issue that the peripheral portion PR of the polishing pad 402 has a significantly lower polishing rate than the central portion CR due to a lack of sufficient polishing liquid SL at the later stage of the service life of the polishing pad 402. Furthermore, the issue of uneven polishing at the later stage of the service life of the polishing pad 402 is resolved. Moreover, compared with the straight hole H1 and the U-shaped hole H2, as described in FIG. 2B, the straight recess T1 and the U-shaped recess T2 have a larger polishing liquid capacity and a significant opening area, thus providing more of the polishing liquid SL in the peripheral portion PR of the polishing pad 402.

In some embodiments, the opening width W_P3 of the straight recess T1 and the individual opening width W_P4 of the U-shaped recess T2 are respectively and substantially equal to the opening width W_C of each central recess R_C in the central portion CR. In these embodiments, the polishing rate of the central portion CR and the peripheral portion PR are approximately the same in the early stage of the service life of the polishing pad 402, while the peripheral portion PR has approximately twice the opening area in the later stage of the service life. With a high polishing uniformity in the early stage of the service life, this design resolves the issue of uneven polishing at the later stage of the service life. In other embodiments, the opening width W_P3 of the straight recess T1 and the individual opening width W_P4 of the U-shaped recess T2 are respectively smaller than the opening width W_C of the central recess R_C.

FIG. 6A is a schematic top view of the polishing pad 602 at the beginning of the service life of the polishing pad 602 according to some embodiments. FIG. 6B is a schematic cross-sectional view along line A-A′ of FIG. 6A. FIG. 7A is a schematic top view of the polishing pad 602 at the later stage of the service life of the polishing pad 602. FIG. 7B is a schematic cross-sectional view along line A-A′ of FIG. 7A.

The polishing pad 602 is similar to the polishing pad 102 described in FIG. 2A, FIG. 2B, FIG. 3A and FIG. 3B, except that the recess design of the peripheral portion PR is different. As shown in FIG. 6A, the peripheral portion PR of the polishing pad 602 is provided with a peripheral recess R_P2 extending continuously along the annulus contour. In detail, each peripheral recess R_P2 is exposed with an upper double annulus recess T3. As a practical example, the double annulus recesses T3 of each peripheral recess R_P2 of the polishing pad 602 extend continuously in the peripheral portion PR along the concentric annulus contour. A person with ordinary knowledge in the art can adjust the number of recesses of peripheral recesses R_P2 according to the size of the peripheral portion PR, and this disclosure is not limited thereto. In addition, the opening width W_P5 of each annulus recess of the double annulus recess T3 is equal to or smaller than the opening width W_C of the central recess R_C.

As shown in FIG. 6B, each peripheral recess R_P2 includes an upper double annulus recess T3 and a plurality of lower holes H3. The holes H3 overlap and are connected to the upper double annulus trench T3. Compared with the double annulus recess T3, hole H3 has a larger opening area (the opening width W_P6 of hole H3 is larger than the total opening width of the double annulus recess T3) and a larger capacity. In addition, compared with each U-shaped hole H2 described in FIG. 2B, each hole H3 has a single opening structure and has a larger diameter area (the diameter width W_P6 of hole H3 is larger than the total diameter width of hole H2) and is more significant in capacity. The polishing liquid SL may enter the peripheral recess R_P2 from the double annulus recess T3 and accumulate in hole H3 as a pool for the polishing liquid.

In the early period of the service life of the polishing pad 602 (as shown in FIG. 6A and FIG. 6B), each peripheral recess R_P2 is only exposed by the upper double annulus recess T3. After the polishing pad 602 is used for a while, the surface gradually wears down so that the upper double annulus recesses T3 of each peripheral recess R_P2 are removed. At this time, as shown in FIG. 7A and FIG. 7B, each peripheral recess R_P2 is exposed as a hole H3 with a larger diameter area. According to some embodiments, as shown in FIG. 7A, the holes H3 are arranged spaced apart from each other in the peripheral portion PR along the annulus contour. As a practical example, the holes H3 are provided in the peripheral portion PR, apart from each other, along two concentric annulus contours and arranged in a radial manner. In the later period of the service life of the polishing pad 602, since the hole H3 exposed is more significant in diameter and area than the double annulus recess T3 exposed in the early period of the service life of the polishing pad 602, the capacity is increased. Thus the extra amount of the polishing liquid SL provided at the peripheral portion PR compensates for the uneven distribution of polishing liquid issue caused by non-uniform conditioning to improve polishing uniformity. Furthermore, compared to the straight hole H1 and the U-shaped hole H2 described in FIG. 2B, the double annulus recess T3 and the hole H3 have a larger polishing liquid capacity and diameter area. Thus, this design provides more polishing liquid SL to the peripheral portion PR of the polishing pad 602.

In the embodiment in which the diameter width W_P5 of each annulus recess of the double annulus recess T3 is approximately equal to the diameter width W_C of each central recess R_C in the central portion CR, the polishing rate of the central portion CR and the peripheral portion PR of the polishing pad 602 in the early stage of the service life are approximately the same, and the opening area of the peripheral portion PR at the later stage of the service life of the polishing pad 602 is more than twice the size. With high polishing uniformity in the early stage of the service life, this design resolves the issue of uneven polishing at the later stage of the service life.

FIG. 8A is a top view of the polishing pad 802 at the later stage of the service life of the polishing pad 802. FIG. 8B is a schematic cross-sectional view along line A-A′ of FIG. 8A.

Although not shown, each peripheral recess R_P3 in the peripheral portion PR of the polishing pad 802 is similar to the peripheral recess R_P2 described in FIG. 6A and FIG. 6B and includes an upper double annulus recess T3. In addition, each peripheral recess R_P3 includes a lower annulus recess T4. Similar to the hole H3 described in FIG. 6B, FIG. 7A and FIG. 7B, the annulus recess T4 overlaps and connects to the upper double annulus recess T3, and has a larger diameter area and capacity than the double annulus recess T3. (The opening width W_P7 of the trench T4 is larger than the total opening width of the double annulus trench T3). As a difference, the annulus recess T4 extends continuously along the bottom of the double annulus recess T3 instead of being separated from each other and provided below the double annulus recess T3. In this design, compared with the hole H3, the annulus recess T4 has a larger diameter area and a larger capacity to provide more polishing liquid, thus able to provide more polishing liquid SL in the peripheral portion PR of the polishing pad 802 at the later stage of the service life of the polishing pad 802.

In summary, this invention provides a chemical mechanical polishing apparatus and a polishing pad for the chemical mechanical polishing apparatus. The edge of the polishing pad is designed with peripheral recess(s) in the peripheral portion. At the beginning of the service life of the polishing pad, the pad exposes an upper part of the peripheral recesses, and at the later stage of the service life of the polishing pad, it exposes a lower part, which has a larger diameter area and capacity of the peripheral recesses. In contrast, the central portion of the polishing pad is designed with central recesses, where the upper and lower parts of the recesses are substantially equal in terms of diameter, area, and capacity. In the early period of the service life of the polishing pad, the upper parts of the central recess and the peripheral recess are exposed with relatively the same diameter area and capacity, providing approximately equal amounts of polishing liquid evenly to the polishing pad. By the later stage of the service life of the polishing pad, the central recess is still exposed to the same diameter area, while the lower part of the peripheral recesses is exposed to a larger diameter area. As a result, the amount of polishing liquid supplied to the peripheral portion of the polishing pad is increased. At the later stage of the service life of the polishing pad, the non-uniform conditioning results in a concave structure from the peripheral to the center, which causes the polishing liquid to flow from the peripheral to the center of the polishing pad. Increasing the amount of polishing liquid provided at the peripheral of the polishing pad at the later stage of the service life of the polishing pad compensates for the decrease in polishing liquid volume due to shape factors. Therefore, at the later stage of the service life of the polishing pad, the central portion and the peripheral portion maintain relatively the same amount of polishing liquid supply. This design ensures that the central and peripheral portions have even and stable polishing rates from the early stage to the later stage of the service life of the polishing pad. In other words, uniform polishing is ensured throughout the entire service life of the polishing pad.

Claims

1. A polishing pad adapted for a chemical mechanical polishing apparatus, and comprising: a central portion provided with a central recess; anda peripheral portion surrounding the central portion with at least one peripheral recess, wherein the at least one peripheral recess is arranged along an annulus contour, and a lower part of the at least one peripheral recess is larger than an upper part of the at least one peripheral recess in diameter area, and different than the upper part of the at least one peripheral recess in shape.

2. The polishing pad according to claim 1, wherein an upper part and a lower part of the central recess are substantially the same in shape and diameter area.

3. The polishing pad according to claim 1, wherein a diameter width of the upper part of the at least one peripheral recess is equal to or smaller than a diameter width of the central recess.

4. The polishing pad according to claim 1, wherein the at least one peripheral recess comprises a plurality of peripheral recesses dispersedly arranged along the annulus contour, and an upper part of each of the peripheral recesses is a straight hole, and a lower part of each of the peripheral recesses is a U-shaped hole with one end connected to the straight hole.

5. The polishing pad according to claim 4, wherein a top part of each of the peripheral recesses formed by a combination of the straight hole and the U-shaped hole is tilted from a vertical direction toward a central axis of the polishing pad, and the central recess extends into the polishing pad along the vertical direction.

6. The polishing pad according to claim 1, wherein the at least one peripheral recess comprises an annulus peripheral recess, an upper part of the annulus peripheral recess is a straight recess extending continuously along the annulus contour, and a lower part of the annulus peripheral recess is a U-shaped recess that continuously extends along the annulus contour and is connected to the straight recess at one end.

7. The polishing pad according to claim 6, wherein a top part of the annulus peripheral recess formed by a combination of the straight recess and the U-shaped recess is tilted from a vertical direction toward a central axis of the polishing pad, and the central recess extends into the polishing pad along the vertical direction.

8. The polishing pad according to claim 1, wherein the at least one peripheral recess comprises an annulus peripheral recess, an upper part of the annulus peripheral recess is a double annulus recess extending continuously along the annulus contour, and a lower part of the annulus peripheral recess comprises a plurality of holes spaced apart along the annulus contour, and the plurality of holes overlap and are connected to the double annulus recesses respectively.

9. The polishing pad according to claim 1, wherein the at least one peripheral recess comprises an annulus peripheral recess, an upper part of the annulus peripheral recess is a double annulus recess extending continuously along the annulus contour, a lower part of the annulus peripheral recess is an annulus recess that extends continuously along the annulus contour, and the annulus recesses overlap and are connected to the double annulus recess.

10. A chemical mechanical polishing apparatus, comprising: a carrier;a polishing pad placed on the carrier and comprising a central portion and a peripheral portion surrounding the central portion, wherein the central portion is provided with a central recess, the peripheral portion is provided with at least one peripheral recess, and the at least one peripheral recess is arranged along an annulus contour, a lower part of the at least one peripheral recess is larger than an upper part of the at least one peripheral recess in diameter area and capacity, and is different from the upper part of the at least one peripheral recess in shape;a wafer suction chuck configured to attach and control a wafer so that the wafer contacts the polishing pad from above; anda polishing liquid supply device configured to provide a polishing liquid to a surface of the polishing pad from above.

11. The chemical mechanical polishing apparatus according to claim 10, further comprising: a polishing pad conditioning device, which contacts the polishing pad from above, configured to remove a polishing residue, and condition a surface of the polishing pad through a rotating disc.

12. The chemical mechanical polishing apparatus according to claim 10, wherein the upper part of the at least one peripheral recess is removed and the lower part thereof is exposed at a later stage of a service life of the polishing pad.

13. The chemical mechanical polishing apparatus according to claim 10, wherein a recess opening area of the peripheral portion of the polishing pad at a later stage of the service life is greater than a recess opening area of the peripheral portion of the polishing pad at an early stage of the service life.

14. The chemical mechanical polishing apparatus according to claim 10, wherein the central portion of the polishing pad maintains substantially a same diameter area in an early stage and a later stage of the service life of the polishing pad.

15. The chemical mechanical polishing apparatus according to claim 10, wherein an upper part and a lower part of the central recess are substantially the same in shape and diameter area.

16. The chemical mechanical polishing apparatus according to claim 10, wherein a diameter width of an upper part of the at least one peripheral recess is equal to or smaller than a diameter width of the central recess.

17. The chemical mechanical polishing apparatus according to claim 10, wherein the at least one peripheral recess comprises a plurality of peripheral recesses dispersedly arranged along the annulus contour, and an upper part of each of the peripheral recesses is a straight hole, and a lower part of each of the peripheral recesses is a U-shaped hole with one end connected to the straight hole.

18. The chemical mechanical polishing apparatus according to claim 17, wherein a top part of each of the peripheral recesses formed by a combination of the straight hole and the U-shaped hole is tilted from a vertical direction toward a central axis of the polishing pad, and the central recess extends into the polishing pad along the vertical direction.

10. The chemical mechanical polishing apparatus according to claim 10, wherein the at least one peripheral recess comprises an annulus peripheral recess, an upper part of the annulus peripheral recess is a straight recess extending continuously along the annulus contour, and a lower part of the annulus peripheral recess is a U-shaped recess that continuously extends along the annulus contour and is connected to the straight recess at one end.

19. The chemical mechanical polishing apparatus according to claim 19, wherein a top part of the annulus peripheral recess formed by a combination of the straight recess and the U-shaped recess is tilted from a vertical direction toward a central axis of the polishing pad, and the central recess extends into the polishing pad along the vertical direction.