CN218891681U - 8 inch or smaller size carrier head and chemical mechanical polishing equipment - Google Patents

Abstract

The utility model discloses a bearing head with the size of 8 inches or less and chemical mechanical polishing equipment, wherein the bearing head comprises a base, a retaining ring, an air film, a compression ring, a first clamping ring and a second clamping ring; the air film comprises a circular bottom plate and a side wall extending upwards vertically along the periphery of the bottom plate, wherein the top of the side wall extends inwards and then bends outwards to be fixedly pressed by the pressing ring and the retaining ring and form a bending part; the air film also comprises an inner partition wall which is formed by extending inwards and horizontally from the side wall and then extending upwards; the first clamping ring is clamped and positioned along the outer side surface of the bending part of the side wall and the second clamping ring is clamped and positioned along the inner side surface of the bending part of the side wall.

Description

8 inch or smaller size carrier head and chemical mechanical polishing equipment

Technical Field

The utility model relates to the technical field of chemical mechanical polishing, in particular to a bearing head with the size of 8 inches or smaller and chemical mechanical polishing equipment.

Background

Chemical mechanical polishing (Chemical Mechanical Polishing, CMP) is a globally planarized ultra-precise surface finish technique. In the polishing method, a wafer is generally placed at the lower part of a bearing head, the bottom surface of the wafer with a deposition layer is abutted against a rotating polishing pad, and the bearing head and the polishing pad rotate in the same direction under the drive of a driving component and give downward load to the wafer; meanwhile, the polishing solution is supplied between the polishing pad and the wafer, and the material removal of the wafer is realized under the combined action of chemistry and machinery.

Small-sized carrier heads, such as 8 inch or 6 inch carrier heads, suffer from poor pressure regulation due to insufficient internal space and limited zoning, and cannot provide more precise control of wafer polishing.

Disclosure of Invention

Embodiments of the present utility model provide a carrier head and chemical mechanical polishing apparatus of 8 inches or less in size, which aim to address at least one of the technical problems in the prior art.

A first aspect of an embodiment of the present utility model provides a 8 inch or smaller sized carrier head comprising a base, a retaining ring, a gas film, a pressure ring, a first snap ring, and a second snap ring;

the air film comprises a circular bottom plate and a side wall extending upwards vertically along the periphery of the bottom plate, wherein the top of the side wall extends inwards and then bends outwards to be fixedly pressed by the pressing ring and the retaining ring and form a bending part;

the air film also comprises an inner partition wall which is formed by extending inwards and horizontally from the side wall and then extending upwards;

the first clamping ring is clamped and positioned along the outer side surface of the bending part of the side wall and the second clamping ring is clamped and positioned along the inner side surface of the bending part of the side wall.

In one embodiment, the thickness of the sidewall below the inner partition wall is greater than the thickness of the sidewall above it.

In one embodiment, the thickness of the sidewall below the inner partition wall decreases with decreasing height forming a trapezoidal sidewall structure.

In one embodiment, the second snap ring is comprised of an annular wall and a horizontal wall.

In one embodiment, a through hole penetrating the second snap ring is provided at an outer peripheral edge of a lower portion of the horizontal wall, so that gas can be discharged from the through hole to act on a root portion of the horizontal wall and press down an edge of the gas film via the trapezoidal sidewall structure.

In one embodiment, the inner partition extends upwardly to be flush with the second snap ring and is clamped at its upper end to the base.

In one embodiment, the bending part is composed of a ring-shaped first horizontal plate, a vertical plate, a second horizontal plate and an inclined fixing plate.

In one embodiment, the first horizontal plate extends horizontally and inwardly along the top of the side wall, and the vertical plate extends vertically upwards along the inner side edge of the first horizontal plate to be flush with the second snap ring and then extends horizontally and outwardly to form a second horizontal plate.

In one embodiment, the second horizontal plate has a width of 30% to 75% of the first horizontal plate.

In one embodiment, the upper surface of the second horizontal plate is provided with a clamp ring which is provided on the top surface of the second clamp ring and which press-fastens the second horizontal plate to the upper surface of the first clamp ring.

A second aspect of an embodiment of the present utility model provides a chemical mechanical polishing apparatus including a carrier head as described above, further including a polishing platen, a dresser, and a polishing liquid supply device.

The beneficial effects of the embodiment of the utility model include: the appearance of wafer edge polishing can be accurately controlled.

Drawings

The advantages of the present utility model will become more apparent and more readily appreciated from the detailed description given in conjunction with the following drawings, which are meant to be illustrative only and not limiting of the scope of the utility model, wherein:

FIG. 1 illustrates a chemical mechanical polishing apparatus provided in accordance with one embodiment of the present utility model;

FIG. 2 illustrates a carrier head provided by an embodiment of the present utility model;

fig. 3 shows a carrier head according to another embodiment of the present utility model.

Detailed Description

The following describes the technical scheme of the present utility model in detail with reference to specific embodiments and drawings thereof. The examples described herein are specific embodiments of the present utility model for illustrating the concept of the present utility model; the description is intended to be illustrative and exemplary in nature and should not be construed as limiting the scope of the utility model in its aspects. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims of the present application and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein. It should be understood that the following description of the embodiments of the present utility model, unless specifically stated otherwise, is established in the natural state of the relevant devices, apparatuses, components, etc. in which no external control signal or driving force is given, in order to facilitate understanding.

Furthermore, it is noted that terms such as front, back, upper, lower, left, right, top, bottom, front, back, horizontal, vertical, and the like used herein are merely used for ease of description to aid in understanding the relative position or orientation and are not intended to limit the orientation of any apparatus or structure.

In order to describe the technical solution according to the utility model, reference will be made to the accompanying drawings and examples.

In this application, chemical mechanical polishing (Chemical Mechanical Polishing) is also referred to as chemical mechanical planarization (Chemical Mechanical Planarization), and wafers are also referred to as wafers, silicon chips, substrates or substrates (substrates), etc., and their meaning and actual function are equivalent.

As shown in fig. 1, a chemical mechanical polishing apparatus 1 according to an embodiment of the present utility model includes a polishing platen 10, a polishing pad 20 bonded to the polishing platen 10, a carrier head 30 that adsorbs a wafer and rotates the wafer, a dresser 40 that dresses the polishing pad 20, a polishing liquid supply device 50 that supplies a polishing liquid to a surface of the polishing pad 20, and a loading carrier (not shown in fig. 1).

Before polishing starts, the robot carries the wafer to the loading carrier, and the carrier head 30 moves from the loading carrier to the above of the polishing platen 10 in the radial direction of the polishing platen 10 after loading the wafer. During chemical mechanical polishing, the carrier head 30 presses the wafer against the polishing pad 20 covered by the surface of the polishing platen 10, and the size of the polishing pad 20 is larger than the size of the wafer to be polished, for example, 1.2 times the size of the wafer or more, thereby ensuring uniform polishing of the wafer. The carrier head 30 is rotated and reciprocated in the radial direction of the polishing pad 10 so that the surface of the wafer in contact with the polishing pad 20 is gradually polished while the polishing pad 10 is rotated, and the polishing liquid supply apparatus 50 sprays the polishing liquid to the surface of the polishing pad 20. The wafer is rubbed against the polishing pad 20 by the relative motion of the carrier head 30 and the polishing platen 10 under the chemical action of the polishing liquid to perform polishing. The polishing solution composed of submicron or nanometer abrasive particles and chemical solution flows between the wafer and the polishing pad 20, the polishing solution is uniformly distributed under the action of the transmission and rotation centrifugal force of the polishing pad 20 to form a layer of liquid film between the wafer and the polishing pad 20, chemical components in the liquid react with the wafer to convert insoluble substances into soluble substances, then the chemical reactants are removed from the surface of the wafer through the micro-mechanical friction of the abrasive particles and dissolved into the flowing liquid to be taken away, namely, surface materials are removed in the alternating process of chemical film formation and mechanical film removal to realize surface planarization treatment, so that the aim of global planarization is achieved. The conditioner 40 is used to condition and activate the surface topography of the polishing pad 20 during polishing. The use of the dresser 40 can remove impurity particles remaining on the surface of the polishing pad 20, such as abrasive particles in the polishing liquid, and waste material that falls off from the wafer surface, and can planarize the deformation of the surface of the polishing pad 20 due to the polishing, ensuring the uniformity of the surface topography of the polishing pad 20 during polishing, and further maintaining a stable polishing removal rate. After polishing is completed, the carrier head 30 adsorbs the wafer to place it on the loading tray, and the robot takes the wafer from the loading tray and then conveys the wafer to the post-processing unit.

Figures 2 and 3 illustrate a carrier head 30 of 8 inches or less provided by the present utility model, the carrier head 30 comprising a base 31, a retaining ring 33, a gas film 34, a pressure ring 32, a first snap ring 35, and a second snap ring 36. The particular configuration of carrier head 30 in the embodiment shown in fig. 2 and 3 is suitable for small size carrier heads 30, such as 8 inches, 6 inches, or less. The small-sized carrier head 30 is difficult to realize partition control and poor in edge regulation capability due to space limitation, and difficult to realize high-precision partition pressure regulation and edge leveling and polishing with high consistency requirements. In the present application, "inner", "outer", "inward" and "outward" refer to the center of the air film 34, and are referred to as "inner" and "outer" when they are close to the center of the air film 34.

As shown in fig. 2, a base 31 is attached below the pivot for supporting a stationary retaining ring 33 and a gas membrane 34.

The retaining ring 33 is mounted below the base 31 and is disposed around the air film 34, the first snap ring 35, and the second snap ring 36. During chemical mechanical polishing, a receiving space is formed between the inner diameter surface of the retainer ring 33 and the lower surface of the gas film 34 for defining the wafer. The bottom surface of the retainer ring 33 faces downward and is opposite to the upper surface of the polishing pad, and the wafer inside the retainer ring 33 is pressed against the upper surface of the polishing pad, and the retainer ring 33 can prevent the wafer from flowing out of the accommodation space and participating in load application of the wafer. In addition, the bottom surface of the retainer ring 33 may be provided with passages for inflow and outflow of the polishing liquid.

As shown in fig. 2, a gas film 34 is clamped below the base 31 to form a pressurizing chamber, a second clamping ring 36 is positioned in the pressurizing chamber, a first clamping ring 35 is arranged outside the pressurizing chamber, and the first clamping ring 35 and the second clamping ring 36 are sleeved and assembled. The material of the second snap ring 36 may be titanium alloy or stainless steel. The first snap ring 35 and the second snap ring 36 are free floating, and the first snap ring 35 and the second snap ring 36 can be sleeved together. When gas is introduced into the pressurized chamber, the pressure in the chamber increases, the pressure is transmitted to the wafer through the gas film 34, and the position and shape of the gas film 34 are defined by the second clamping ring 36 and the first clamping ring 35 which are matched with each other.

The first snap ring 35 and the second snap ring 36 may be sleeved together, specifically, the first snap ring 35 is annular, and the second snap ring 36 is formed by an annular wall 361 and a horizontal wall 362. The annular wall 361 is formed to extend upward from the upper surface of the horizontal wall 362, and the annular wall 361 is spaced apart from the outer circumferential edge of the horizontal wall 362, so that an annular space is formed in the upper edge region of the second snap ring 36, which can be matched with the first snap ring 35, with which the annular first snap ring 35 can be fitted around the outer circumference of the annular wall 361.

As shown in fig. 2, in one embodiment, a compression ring 37 is further provided on the upper surface of the second snap ring 36, i.e., between the second snap ring 36 and the base 31. The clamp ring 37 may be made of a material having elasticity. The clamp ring 37 serves to cushion the collision between the second clamp ring 36 and the base 31 and to press a part of the air film 34.

In one embodiment of the present utility model, as shown in fig. 2, the air film 34 includes a circular bottom plate 341 and a sidewall 342 extending vertically upward along the outer circumference of the bottom plate 341, and the top of the sidewall 342 extends inward and then bends outward until being pressed and fixed by the pressing ring 32 and the retaining ring 33, and forms a bending portion 343.

As shown in fig. 2, the edge of the air film 34 is sandwiched between the retaining ring 33 and the base 31, that is, the edge of the side wall 342 is sandwiched between the retaining ring 33 and the base 31. Specifically, the edge of the side wall 342 is clamped by the pressing ring 32 and the retaining ring 33, the pressing ring 32 is embedded into the bottom of the base 31, a sealing ring for avoiding air leakage is arranged between the pressing ring 32 and the base 31, and the retaining ring 33 can be fixed at the bottom of the base 31 in a threaded fixing manner, so that the edge of the air film 34 is clamped between the retaining ring 33 and the pressing ring 32.

As shown in fig. 2, the side wall 342 of the air film 34 has a bent portion 343, the bent portion 343 extends between the first snap ring 35 and the second snap ring 36 in a bent manner, and the first snap ring 35 is engaged with and positions the bent portion 343 along an outer side surface of the bent portion 343 of the side wall 342 and the second snap ring 36 is engaged with and positioned along an inner side surface of the bent portion 343 of the side wall 342. The side wall 342 is formed to extend upward from the outer peripheral edge of the bottom plate 341, and the bent portion 343 is formed to extend inward, upward, and then outward in this order of the side wall 342. Specifically, the side wall 342 extends upward around the outer peripheral surface of the second snap ring 36, then extends inward between the bottom surface of the first snap ring 35 and the second snap ring 36, then extends upward along the inner peripheral surface of the first snap ring 35, then extends outward on the top surface of the first snap ring 35, and the side wall 342 extends above the top surface of the first snap ring 35 to be attached to the base 31.

As shown in fig. 2, the bending portion 343 is formed of a ring-shaped first horizontal plate, a vertical plate, a second horizontal plate, and an inclined fixing plate.

Wherein the first horizontal plate extends horizontally inward along the top of the side wall 342, and the vertical plate extends vertically upward along the inner edge of the first horizontal plate to be flush with the second snap ring 36 and then extends horizontally outward to form a second horizontal plate. The first horizontal plate is located between the bottom surface of the first snap ring 35 and the top surface of the horizontal wall 362 of the second snap ring 36. The vertical plate is located between the inner peripheral surface of the first snap ring 35 and the outer peripheral surface of the annular wall 361 of the second snap ring 36. The second horizontal plate is attached to the top surface of the first snap ring 35.

Further, in one embodiment, the angled retention plate of the bend 343 adds to the fold structure, i.e., the surface of the retention plate is not smooth, but has a fold. By adding the fold structure to the fixing plate portion of the air film 34 between the first snap ring 35 and the retaining ring 33, the axial flexibility of the air film 34 can be improved, the abrasion sensitivity of the retaining ring 33 can be reduced, in other words, even if the bottom surface of the retaining ring 33 is partially abraded and the height of the retaining ring 33 is reduced, the carrier head 30 can still work normally, and the fold structure at the edge of the air film 34 can enable the air film 34 to be improved in flexibility and still adapt to the abrasion condition of the retaining ring 33.

In one embodiment, the width of the second horizontal plate is 30% to 75% of the width of the first horizontal plate.

As shown in fig. 2, the upper surface of the second horizontal plate is provided with a clamp ring 37 which is provided on the top surface of the second clamp ring 36 and which clamps the second horizontal plate to the upper surface of the first clamp ring 35.

In one embodiment of the present utility model, as shown in FIG. 2, the air film 34 further includes an inner partition 344 extending horizontally inwardly from the side walls 342 and then upwardly. An inner partition 344 is formed around the bottom surface and the inner peripheral surface of the second snap ring 36, the inner partition 344 extending upward to be flush with the second snap ring 36, and the upper end thereof being snapped to the base 31.

As shown in fig. 2, in one embodiment, the thickness of the side wall 342 below the inner partition 344 is greater than the thickness of the side wall 342 above it.

As shown in fig. 2, in one embodiment, the thickness of the side walls 342 below the inner partition 344 decreases with decreasing height to form a trapezoidal side wall 342 structure.

Further, as shown in fig. 2, the air film 34 further includes a first diaphragm 345 and a second diaphragm 346 located inside the inner partition 344, the second diaphragm 346 is located inside the first diaphragm 345, and the first diaphragm 345 and the second diaphragm 346 are annular, and may be made of thin and flexible vertical ribs. In this embodiment, the first diaphragm 345 and the second diaphragm 346 located in the middle area of the air film 34 use vertical ribs, so that collapse between adjacent chambers caused by pressure difference can be prevented, and pressure fluctuation at the diaphragm position caused by the collapse can be avoided.

As shown in fig. 2, based on the gas film 34 including a bottom plate 341, a side wall 342, an inner partition 344, a first diaphragm 345, a second diaphragm 346 and a structure, the gas film 34 encloses a plurality of concentric relatively sealed pressure-adjustable chambers under the base 31, and specifically includes a first chamber Z1, a second chamber Z2, a third chamber Z3 and a fourth chamber Z4 concentrically arranged from edge to center in sequence. The central fourth chamber Z4 is circular, and the first chamber Z1, the second chamber Z2, and the third chamber Z3 are concentric annular. As shown in fig. 2, the bottom plate 341, the side wall 342, and the inner partition 344 of the air film 34 define a first chamber Z1 therebetween, a second chamber Z2 is defined between the bottom plate 341, the inner partition 344, and the first diaphragm 345, a third chamber Z3 is defined between the bottom plate 341, the first diaphragm 345, and the second diaphragm 346, and a fourth chamber Z4 is defined between the bottom plate 341 and the annular second diaphragm 346. Wherein the first membrane 345 and the second membrane 346 are each formed by extending vertically upward from the bottom plate 341 of the gas film 34.

The internal pressures of the first chamber Z1, the second chamber Z2, the third chamber Z3 and the fourth chamber Z4 are independent and can be respectively changed, and accordingly, the wafer surface is divided into a plurality of corresponding partitions by different pressurizing chambers of the carrier head 30, so that polishing pressures of the 4 areas corresponding to the wafer surface, namely, the central area, the first middle area, the second middle area and the peripheral area of the wafer surface can be independently adjusted. Each pressurizing chamber can apply different pressures to the corresponding wafer surface subareas, and different pressures can be applied to the different subareas of the wafer surface by respectively controlling the pressure of fluid such as pressurized air and the like supplied to the pressurizing chambers. Specifically, gases may be introduced into or withdrawn from the first, second, third, and fourth chambers Z1, Z2, Z3, and Z4, respectively, through not-shown through holes or fluid passages to adjust the pressure of the chambers, thereby precisely adjusting the pressure profile applied to the wafer in zones to achieve more uniform polishing.

As shown in fig. 2, the second snap ring 36 is positioned within the first chamber Z1 such that when gas is introduced into the first chamber Z1, the gas pressure acts on the second snap ring 36, thereby causing the second snap ring 36 to exert a downward pressure on the side wall 342 below the inner partition 344. When the gas is introduced into the second chamber Z2, the gas pressure acts on the side wall 342 below the inner partition 344. Therefore, the acting force of the side wall 342 of the air film 34 on the wafer edge area through the bottom plate 341 of the air film 34 can be regulated through the dual functions, and the polishing morphology of the wafer edge can be regulated more accurately.

In this embodiment, a plurality of pressure partitions, namely, a first chamber Z1, a second chamber Z2, a third chamber Z3 and a fourth chamber Z4, are added to the carrier head 30 with a size of 8 inches or less, so as to improve the pressure regulating capability of the carrier head 30, i.e., to achieve better capability of regulating the removal rate of each area on the wafer surface according to the requirements, thereby satisfying more processes. In addition, the edge chamber (i.e., the first chamber Z1) of the gas film 34 is designed to reduce the pressure transmitted by the sidewall 342, thereby achieving more precise control of the outer polishing.

As shown in fig. 3, in one embodiment of the present utility model, a through hole 38 penetrating the second snap ring 36 is provided at the outer peripheral edge of the lower portion of the horizontal wall 362, so that gas can be discharged from the through hole 38 to act on the root of the horizontal wall 362 and press down the edge of the gas film 34 via the trapezoidal sidewall 342 structure.

The second snap ring 36 is provided with a through hole 38 therethrough, and the through hole 38 communicates with the top surface and the outer peripheral surface of the second snap ring 36, or the through hole 38 communicates with the top surface and the bottom surface of the second snap ring 36. Specifically, the through hole 38 extends from the outer peripheral surface outlet at the top surface opening of the second snap ring 36 inside the second snap ring 36, or the through hole 38 extends downward from the bottom surface outlet at the top surface opening of the second snap ring 36. The through hole 38 is used for communicating the area above the second clamping ring 36 and the area below or beside the second clamping ring 36 in the first chamber Z1 to ensure stable air supply and air pressure.

The embodiment shown in fig. 3 adds the through hole 38 to the second clamping ring 36, so that the edge pressurization is stable, that is, the pressurization in the first chamber Z1 is stable, the edge cannot enter or exhaust due to compaction between the second clamping ring 36 and the air film 34, and the controllability of the edge pressure can be ensured.

In summary, the present application has the following advantages:

(1) A plurality of pressure chambers can be arranged in the air film 34, and more accurate control on wafer polishing is achieved through pressure regulation;

(2) Increasing the thickness of the lower half of the sidewall 342 of the air film 34 prevents wear;

(3) The cooperation design of the side wall 342 and the inner partition wall 344 of the air film 34, and the design of the vertical ribs adopted by the first diaphragm 345 and the second diaphragm 346 positioned in the middle area of the air film 34 can effectively reduce the complex influence of the pulling and pressing state and the pressure difference on the pressure transmission of the bottom plate 341 of the air film 34;

(4) The inclined fixing plate of the air film 34 is provided with folds, so that the problem of chip loading failure or chip unloading failure caused by insufficient axial flexibility in the chip loading or unloading process can be prevented.

The drawings in the present specification are schematic views, which assist in explaining the concept of the present utility model, and schematically show the shapes of the respective parts and their interrelationships. It should be understood that for the purpose of clearly showing the structure of various parts of embodiments of the present utility model, the drawings are not drawn to the same scale and like reference numerals are used to designate like parts in the drawings.

In the description of the present specification, a description with reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., are intended to mean that the embodiment or embodiments are combined

The specific features, structures, materials, or characteristics described in the examples are included in at least one embodiment 5 or example of the present utility model. In the present specification, a schematic representation of the above terms does not necessarily refer to the same entities

Embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described, those of ordinary skill in the art will recognize that

Understanding: numerous 0 variations, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the utility model, the scope of which is defined by the claims and their equivalents.

Claims (11)

1. A carrier head of 8 inches or less in size comprising a base, a retaining ring, a gas film, a pressure ring, a first snap ring, and a second snap ring;

the air film comprises a circular bottom plate and a side wall extending upwards vertically along the periphery of the bottom plate, wherein the top of the side wall extends inwards and then bends outwards to be fixedly pressed by the pressing ring and the retaining ring and form a bending part;

the air film also comprises an inner partition wall which is formed by extending inwards and horizontally from the side wall and then extending upwards;

the first clamping ring is clamped and positioned along the outer side surface of the bending part of the side wall and the second clamping ring is clamped and positioned along the inner side surface of the bending part of the side wall.

2. The carrier head of claim 1, wherein the thickness of the sidewall below the inner partition wall is greater than the thickness of the sidewall above it.

3. The carrier head of claim 2, wherein the thickness of the sidewalls below the inner partition wall decreases with decreasing height to form a trapezoidal sidewall structure.

4. The carrier head of claim 3, wherein the second snap ring is formed of an annular wall and a horizontal wall.

5. The carrier head of claim 4, wherein a through hole penetrating the second snap ring is provided at an outer peripheral edge of a lower portion of the horizontal wall so that gas can be discharged from the through hole to act on a root portion of the horizontal wall and press down an edge of the gas film via the trapezoidal sidewall structure.

6. The carrier head of claim 1, wherein the inner bulkhead extends upwardly to be flush with the second snap ring and is clamped at its upper end to the base.

7. The carrier head of claim 1, wherein the bend is formed by a first annular horizontal plate, a vertical plate, a second horizontal plate, and an angled fixed plate.

8. The carrier head of claim 7, wherein the first horizontal plate extends horizontally inwardly along the top of the side wall, and the vertical plate extends vertically upwardly along the inner edge of the first horizontal plate to be flush with the second snap ring and then extends horizontally outwardly to form a second horizontal plate.

9. The carrier head of claim 8, wherein the second horizontal plate has a width of 30% to 75% of the width of the first horizontal plate.

10. The carrier head of claim 9, wherein the upper surface of the second horizontal plate is provided with a clamp ring that is disposed on the top surface of the second clamp ring and that clamps and secures the second horizontal plate to the upper surface of the first clamp ring.

11. A chemical mechanical polishing apparatus comprising the carrier head according to any one of claims 1 to 10, further comprising a polishing platen, a dresser, and a polishing liquid supply means.

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