KR102323727B1 - Retainer ring in carrier head for chemical mechanical polishing apparatus and carrier head having the same - Google Patents

Abstract

Disclosed are a retainer ring of a carrier head for a chemical mechanical polishing apparatus and a carrier head having the same. A carrier head according to an embodiment includes a carrier head body; a membrane connected to the lower side of the carrier head body for pressing the gripped substrate against the polishing pad; a retainer ring connected to the carrier head body so as to surround an outer surface of the membrane, forming a gap with the membrane, and restraining a side surface of the gripped substrate; and a cleaning liquid injection unit formed on the carrier head body and configured to supply the cleaning liquid to the gap.

Description

Retainer ring of carrier head for chemical mechanical polishing apparatus and carrier head having same

The following embodiment relates to a retainer ring of a carrier head for a chemical mechanical polishing apparatus and a carrier head having the same, and more specifically, a carrier for a chemical mechanical polishing apparatus capable of effectively removing the slurry and foreign substances introduced into the inner surface of the retainer ring. It relates to a retainer ring of a head and a carrier head having the same.

The chemical mechanical polishing (CMP) device is used for wide area planarization and circuit formation that removes the height difference between the cell area and the surrounding circuit area due to the unevenness of the wafer surface that is generated while repeatedly performing masking, etching, and wiring processes during the semiconductor device manufacturing process. It is a device used to precisely polish the surface of a wafer in order to improve the surface roughness of the wafer according to contact/wiring film separation and high-integration device.

In this CMP apparatus, the carrier head presses the wafer with the polishing surface facing the polishing pad before and after the polishing process to perform the polishing process, and at the same time, when the polishing process is finished, the wafer is directly and indirectly removed. It moves to the next process in the state of being held by vacuum adsorption.

1 and 2 , the carrier head 1 has a body part 110 , a base part 120 rotating together with the body part 110 , and up and down in a ring shape surrounding the base part 120 . The pressure chambers C1, C2, C3, C4, C5 are formed in a space between the retaining ring 130 that is movably mounted and rotates together with the base part 120 and the retainer ring 130 fixed to the base part 120 and the base part 120 . ) forming a membrane 140 of an elastic material, and a pressure control unit 150 that adjusts the pressure while introducing or removing air into the pressure chambers C1, C2, C3, C4, and C5 through the pneumatic supply path 155. do.

The elastic membrane 140 has a bent side 142 formed at the edge end of the flat bottom plate 141 that presses the wafer (W). The central end 140a of the membrane 140 is fixed to the base 120 so that a suction hole 77 for directly sucking the wafer W is formed. A suction hole is not formed in the central portion of the membrane 150 and may be formed as a surface for pressing the wafer W. A plurality of ring-shaped partition walls 143 fixed to the base part 120 are formed between the center of the membrane 140 and the side surface 142, and a plurality of pressure chambers C1, C2, C3, C4, C5) are arranged in concentric circles.

Accordingly, while the pressure chambers C1, C2, C3, C4, and C5 expand by the pneumatic pressure applied from the pressure control unit 150 during the chemical mechanical polishing process, the wafer W through the membrane bottom plate 141 is press the plate.

At the same time, the bottom surface 130s of the retainer ring 130, which rotates together with the body portion 110 and the base portion 120, also rotates while pressing the polishing pad 11, so that the wafer surrounded by the retainer ring 130 ( W) is prevented from escaping to the outside of the carrier head (1).

On the other hand, since the retainer ring 130 is mounted to be movable up and down with respect to the body 110 and the base 120, it ensures vertical movement of the retainer ring with respect to the membrane fixedly installed on the body 100 (maintaining a non-contact state). ), a gap is formed between the membrane and the retainer ring.

However, there is a problem in that the slurry S supplied to the polishing surface of the polishing pad 11 during the conventional polishing process flows into the gap formed between the membrane 140 and the retainer ring 130 and remains thereafter.

In particular, if the slurry S flowing into the gap L1 between the membrane 140 and the retainer ring 130 is not quickly removed, the slurry introduced into the gap L1 is fixed, so that the retainer ring 130 is smoothly formed. There is a problem that prevents vertical movement, and the slurry remaining in the gap L1 is attached to the substrate or the membrane again or acts as an S/C source.

Therefore, in the prior art, the cleaning solution was sprayed into the gap L1 formed between the membrane 140 and the retainer ring 130 to remove the slurry S flowing into the gap L1, but it was supplied to the gap L1. Since the washed cleaning solution 15 is not sufficiently spread and escapes as it is, there is a problem in that it is difficult to effectively remove the slurry remaining in the gap between the membrane 140 and the retainer ring 130 .

To this end, recently, various studies have been made to effectively remove foreign substances (slurry and particles) remaining in the gap between the retainer ring and the membrane, but it is still insufficient and development thereof is required.

It is an object of the present invention to provide a retainer ring of a carrier head for a chemical mechanical polishing apparatus capable of effectively removing foreign substances remaining in a gap between the retainer ring and a membrane, and a carrier head having the same.

In particular, an object of the present invention is to allow the cleaning solution supplied between the gap between the retainer ring and the membrane to sufficiently spread, thereby effectively removing the slurry and foreign substances introduced into the inner surface of the retainer ring.

In addition, an object of the present invention is to reduce costs and improve process efficiency and yield.

Another object of the present invention is to increase stability and reliability and to improve precision.

Another object of the present invention is to improve the workability and assembly of the retainer ring, and to increase the flatness of the retainer ring with respect to the polishing pad.

Another object of the present invention is to simplify the replacement process of the retainer ring and shorten the time required for the replacement process.

In addition, an object of the present invention is to improve productivity and yield, and to reduce manufacturing cost.

A carrier head according to an embodiment includes a carrier head body; a membrane connected to the lower side of the carrier head body for pressing the gripped substrate against the polishing pad; a retainer ring connected to the carrier head body so as to surround an outer surface of the membrane, forming a gap with the membrane, and restraining a side surface of the gripped substrate; and a cleaning liquid injection unit formed on the carrier head body and configured to supply the cleaning liquid to the gap.

In one aspect, the cleaning liquid injection unit may collect the cleaning liquid falling to the upper portion of the carrier head body and flow it into the gap.

In one side, the cleaning liquid injection unit is a slot formed on the upper surface of the carrier head body; and a cleaning flow passage passing through the carrier head body from the slot and communicating with the gap.

In one side, the slot may be formed on an upper surface of the carrier head body to be stepped inward, and the cleaning passage may communicate with an inlet formed on an inner surface of the slot.

In one aspect, based on a state viewed from the top of the carrier head body, the inlet may have a smaller area than the slot.

In one side, a plurality of inlets may be formed in the slot, and a plurality of cleaning passages may be in communication with each of the plurality of inlets.

In one side, the cleaning passage may include: a first cleaning passage formed through the carrier head in a vertical direction from the slot; and a second cleaning flow path having one side communicating with the first cleaning flow path, the other side communicating with the gap, and having a cross-sectional area smaller than that of the first cleaning flow path.

In one side, a portion of the cleaning flow passage communicating with the gap may have a smaller cross-sectional area than a portion communicating with the slot.

In one side, the retainer ring may include a guide projection protruding from the inner surface to face the outer surface of the membrane.

In one side, the guide protrusion may include an upper inclined surface for guiding the cleaning solution supplied to the upper portion of the gap to the outer surface of the membrane.

In one side, the guide protrusion may include a lower inclined surface for guiding the cleaning solution supplied to the lower portion of the gap to the outer surface of the membrane.

In one side, the guide protrusion may include at least one of an upper inclined surface inclined downwardly toward the membrane or a lower inclined surface inclined upward toward the membrane, based on a cross-section.

In one side, the retaining ring may include: a through hole formed through a lower surface in a radial direction; and a connection passage having one end communicating with the through groove and the other end communicating with the gap.

In a carrier head for holding a substrate according to an embodiment, the carrier head includes: a slot formed on an upper surface to collect a cleaning solution supplied from the outside; and a cleaning passage for flowing the cleaning liquid collected in the slot downward.

In one aspect, the cleaning passage may supply the cleaning solution to a gap between a membrane for pressing the substrate and a retainer ring surrounding an outer surface of the membrane.

In one side, the slot may be formed to be recessed in a stepped manner in the upper surface of the carrier head, and the cleaning flow path may communicate with an inlet formed in the slot.

A carrier comprising a carrier head body according to an embodiment, a membrane connected to a lower side of the carrier head body and pressing a substrate, and a ring-shaped retainer ring connected to the carrier head body to surround an outer surface of the membrane in the head,

The carrier head is disposed on the carrier head body and includes a cleaning solution supply device for dropping the cleaning solution onto an upper surface of the carrier head body, the carrier head receiving the cleaning solution falling from the cleaning solution supply device to the retaining and membrane It can flow through the gap between them.

In one side, the carrier head is recessed in the upper surface of the carrier head body, the slot in which the inlet is formed; and a cleaning flow passage formed through the carrier head body, one side communicating with the inlet and the other end communicating with the outlet formed on the lower surface of the carrier head body to communicate with the gap.

In one side, a cross-sectional area of the inlet may be greater than a cross-sectional area of the outlet.

According to an embodiment, a carrier head for pressing a substrate against a polishing pad during a chemical mechanical polishing process, the carrier head comprising: a carrier head body; a membrane mounted on a lower surface of the carrier head body and pressing the substrate against the polishing pad; and a retaining ring disposed to be spaced apart from the outer surface of the membrane, and a guide protrusion protruding from an inner surface of the retaining body, the retainer ring being coupled to the carrier head body to constrain the side surface of the substrate. can do.

In one aspect, the retaining ring may include a flat portion and a non-planar portion formed on an upper surface, the flat portion may be in contact with the carrier head body, and the non-planar portion may be non-contacting the carrier head body.

In one aspect, based on a state viewed from the upper surface of the retaining ring, the non-flat portion may have a larger area than the flat portion.

In one aspect, the retainer ring may include a guide groove recessed in the non-planar portion, and the carrier head body may include an insertion protrusion that protrudes toward a bottom surface and is accommodated in the guide groove.

As described above, according to the present invention, it is possible to obtain an advantageous effect of effectively removing the slurry remaining between the gap between the retainer ring and the membrane.

In particular, according to the present invention, since the cleaning liquid supplied to the inner surface of the retaining body is sufficiently spread, it is possible to obtain an advantageous effect of increasing the cleaning efficiency of the gap (the gap between the membrane and the retaining body) by the cleaning liquid.

In addition, according to the present invention, it is possible to minimize the occurrence of an uncleaned region (a region in which cleaning by a cleaning solution is not performed) in the gap between the retainer ring and the membrane, and advantageous effects of further increasing cleaning efficiency can be obtained.

In addition, according to the present invention, the time and cost required for slurry removal can be reduced, and advantageous effects of improving process efficiency and yield can be obtained.

In addition, according to the present invention, it is possible to obtain advantageous effects of improving the workability and assembling properties of the retainer ring and increasing the flatness of the retainer ring with respect to the polishing pad.

In addition, according to the present invention, it is possible to obtain an advantageous effect of simplifying the replacement process of the retainer ring and shortening the time required for the replacement process.

In addition, according to the present invention, it is possible to obtain advantageous effects of improving productivity and yield, and reducing manufacturing cost.

The following drawings attached to this specification illustrate a preferred embodiment of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention, so the present invention is limited to the matters described in those drawings It should not be construed as being limited.
1 is a cross-sectional view showing a conventional carrier head.
FIG. 2 is an enlarged view of part 'A' of FIG. 1 .
3 is a schematic diagram of a substrate polishing system according to an embodiment.
4 is a partial perspective view of a carrier head according to an embodiment;
5 is a partial cross-sectional view of a carrier head according to one embodiment;
6 is a cross-sectional view of a carrier head according to one embodiment;
FIG. 7 is an enlarged view of part 'B' of FIG. 6 .
8 to 10 are cross-sectional views of a retaining ring according to an exemplary embodiment.
11 is a cross-sectional view of a carrier head according to an embodiment.
12 is a bottom view of a retaining ring according to an embodiment.
13 is a cross-sectional view of a carrier head according to an embodiment.
14 and 15 are top views of a retaining ring according to an exemplary embodiment.
16 is a cross-sectional view of a carrier head according to an embodiment.
17 is a cross-sectional view of a carrier head according to an embodiment.

Hereinafter, embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in the description of the embodiment, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It will be understood that may also be "connected", "coupled" or "connected".

Components included in one embodiment and components having a common function will be described using the same names in other embodiments. Unless otherwise stated, a description described in one embodiment may be applied to another embodiment, and a detailed description in the overlapping range will be omitted.

3 is a schematic diagram of a substrate polishing system according to an embodiment, FIG. 4 is a partial perspective view of a carrier head according to an embodiment, FIG. 5 is a cross-sectional view of a carrier head according to an embodiment, and FIG. 6 is an embodiment Here is a partial cross-sectional view of another carrier head.

3 to 6 , the substrate polishing system according to an exemplary embodiment may be used in a chemical mechanical planarization (CMP) process for polishing the surface of the substrate W. The substrate W polished through the substrate polishing system may be a silicon wafer for manufacturing a semiconductor device. However, the type of the substrate W is not limited thereto. For example, the substrate W may include glass for a liquid crystal display (LCD) or a plasma display device (FPD).

The substrate polishing system can increase process efficiency by effectively removing foreign substances generated in the polishing process of the substrate W, and ensure the polishing uniformity of the substrate W. The substrate polishing system may include a carrier head 100 and a cleaning solution supply device 20 .

The carrier head 100 may hold the polishing target substrate W and contact the polishing pad 11 . The carrier head 100 receives the substrate W from the cradle (not shown) and receives the substrate W in a state in which the slurry S is supplied to the upper surface of the polishing pad 11 (not shown) provided on the polishing platen (not shown). (W) can be pressed to perform a chemical mechanical polishing process. After the chemical mechanical polishing process using the polishing pad and the slurry S is completed, the carrier head 100 may transfer the substrate W to the cleaning apparatus. The carrier head 100 may include a carrier head body 101 , a membrane 140 , a retainer ring 130 , and a cleaning solution injection unit 170 .

The carrier head body 101 may include a main body part 110 connected to a driving shaft (not shown) to rotate, and a base part 120 connected to the main body part 110 to rotate together.

The main body 110 may be rotationally driven according to the operation of the drive shaft by having an upper end coupled to the drive shaft. For reference, in the drawings, an example in which the main body 110 is formed as a single body is described, but unlike this, the main body may be configured by combining two or more bodies.

The base part 120 may be disposed to be aligned coaxially with the body part 110 , and may be coupled to the body part 110 to rotate together with the body part 110 .

The membrane 140 may be connected to the lower side of the carrier head body 101 , and may press the substrate W against the polishing pad 11 . The membrane 140 may be formed of an elastically flexible material. For example, the elastically flexible material may be polyurethane. The membrane 140 has a circular bottom plate 141 facing the non-polishing surface of the substrate W, a side bent from the edge end of the bottom plate 141 and extending in the upper vertical direction, and the bottom plate 141 . It is formed between the center and the side of the ring, and may include a plurality of barrier ribs 143 in the form of a ring coupled to the base portion (120). With this structure, a plurality of pressure chambers C1 to C5 divided by the partition wall 143 may be formed between the membrane 140 and the base part 120 .

A pressure sensor for measuring a pressure may be provided in each of the plurality of pressure chambers C1 to C5. The pressure of each of the pressure chambers C1 to C5 is controlled by the pressure control unit 150 and thus can be individually adjusted.

The retainer ring 130 may be formed in a ring shape and connected to the carrier head body 101 to maintain the position of the substrate W with respect to the carrier head 100 during a chemical mechanical polishing process. The retainer ring 130 may be connected to the carrier head body 101 to surround the outer surface of the membrane 140 . In a state in which the substrate W is gripped on the lower side of the membrane 140, the retainer ring 130 surrounds and restrains the side surface of the gripped substrate W, thereby preventing the substrate W from being separated from the gripping position between polishing processes. can be prevented

The retainer ring 130 may be spaced apart from the outer surface of the membrane 140 by a predetermined distance. The diameter of the inner circumferential surface of the retainer ring 130 needs to be slightly larger than the diameter of the outer diameter of the membrane 140 according to manufacturing needs or process needs. Accordingly, a predetermined gap G may be formed between the inner circumferential surface of the retainer ring 130 and the outer surface of the membrane 140 facing each other.

The retainer ring 130 may include a retaining ring body 131 and a guide protrusion 138 protruding from an inner surface of the retaining ring body 131 .

The retaining ring body 131 may be formed in a ring shape. The retaining ring body 131 may include a ring-shaped first ring member 132 and a ring-shaped second ring member 134 stacked under the first ring member 132 . Accordingly, the retaining body 131 may wrap around the substrate W positioned under the bottom plate 141 of the membrane 140 during the chemical mechanical polishing process. Meanwhile, in the drawings, the case in which the retaining ring body 131 is composed of two parts is exemplified, but otherwise, the case in which the retaining ring body 131 is formed of a single ring member is also possible. Hereinafter, for convenience of description, a case in which the retaining ring body 131 is composed of two parts of the first ring member 132 and the second ring member 134 will be mainly described.

The first ring member 132 may be formed of a conductive material, for example, a metal material. On the other hand, the second ring member 134 may be formed of a non-conductive material, for example, a material such as engineering plastic or resin.

The retainer ring 130 may move up and down with respect to the carrier head body 101 by the pressure of a ring-shaped pressure chamber (not shown) located on the upper side. For example, a lower member that moves up and down integrally with the retainer ring 130, an upper member positioned above the lower member and disposed in contact with the upper surface of the lower member, and a contact surface of the lower member and the upper member around the contact surface A pressure chamber may be formed by the surrounding flexible ring member. In this case, the degree to which the retainer ring 130 presses the surface of the polishing pad may be controlled while the distance between the lower member and the upper member is adjusted according to the pressure supplied from the pressure controller to the pressure chamber.

The cleaning liquid injection unit 170 is formed in the carrier head body 101 , and may supply the cleaning liquid F to the gap G between the retainer ring 130 and the membrane 140 .

In the polishing process of the substrate W, foreign substances such as residues generated from polishing the substrate W and the slurry S may flow into the gap G between the retainer ring 130 and the membrane 140 . Foreign substances introduced into the gap G may interfere with the movement of the retainer ring 130 or cause a phenomenon of lowering the polishing degree of the substrate W by adhering to the substrate W or the membrane 140 in reverse in the polishing process. can

The cleaning liquid injection unit 170 may collect the cleaning liquid F supplied from the outside of the carrier head 100 and flow it into the gap G between the membrane 140 and the retainer ring 130 . That is, since the cleaning solution injection unit 170 flows the cleaning solution F from the top to the bottom of the gap G, foreign substances introduced into the gap G between the retainer ring 130 and the membrane 140 are effectively removed. can do.

The cleaning solution injection unit 170 may include a slot 171 formed on the upper surface of the carrier head body 101 and a cleaning flow path 173 communicating from the slot 171 to the gap G.

The slot 171 may collect the cleaning liquid F falling on the upper portion of the carrier head body 101 . The slot 171 may be formed on the upper surface of the carrier head body 101 to be stepped inward. When the cleaning liquid F is supplied to the upper portion of the carrier head body 101 , the cleaning liquid F flows into the slot 171 , so that it can be effectively collected.

The cleaning flow path 173 is formed by vertically penetrating the carrier head body 101 so as to flow the cleaning liquid F from the slot 171 to the gap G between the retainer ring 130 and the membrane 140 . can be One side of the cleaning flow path 173 may communicate with the inlet 172 formed in the slot 171 , and the other side may communicate with the outlet formed on the lower surface of the carrier head body 101 so as to be connected to the gap G . According to this structure, the cleaning liquid F collected in the slot 171 is injected into the cleaning passage 173 through the inlet 172 , and flows along the cleaning passage 173 into the gap G through the outlet. can be emitted.

As shown in FIG. 4 , the inlet 172 may have a smaller area than the slot 171 when viewed from the top of the carrier head body 101 . When the cleaning passage 173 is formed in the carrier head body 101 , the cleaning passage 173 may be limited within a predetermined size. In general, the diameter of the cleaning flow path 173 may be limited to within 5 mm. In this case, a phenomenon in which the cleaning liquid F is not efficiently introduced into the inlet 172 may occur. Since the slot 171 is formed on the upper surface of the carrier head body 101 , it may be formed to have a larger area than the inlet 172 . Accordingly, when the cleaning liquid F is supplied to the upper portion of the carrier head body 101 , the cleaning liquid F is primarily collected in the slot 171 , and secondly through the inlet 172 in the slot 171 . By supplying the cleaning flow path 173 , it can flow into the gap G more stably and efficiently.

Meanwhile, a plurality of inlets 172 may be formed in the carrier head body 101 . The plurality of inlets 172 may be formed along the circumferential direction of the carrier head body 101 . In this case, a plurality of inlets 172 may be formed in one slot 171 , and a plurality of cleaning passages may be respectively communicated with each of the plurality of inlets 172 . According to this structure, compared to the case of supplying the cleaning liquid F to each of the plurality of cleaning passages, the cleaning liquid F is primarily collected in the slot 171 and the inlet 172 in the slot 171 according to its own weight. ), the cleaning liquid F may flow into the gap G between the retainer ring 130 and the membrane 140 more effectively because it is secondarily introduced into each cleaning passage.

The cleaning passage 173 may have a different cross-sectional area for each part. For example, the cleaning flow path 173 may have a smaller cross-sectional area at a portion adjacent to the gap G than at a portion adjacent to the slot 171 . Specifically, the portion of the cleaning flow path 173 communicating with the gap G, that is, the cross-sectional area of the outlet, may be smaller than the cross-sectional area of the portion communicating with the slot 171 , that is, the inlet 172 . According to this structure, the cross-sectional area of the inlet 172 is widened so that the cleaning liquid F is effectively supplied to the cleaning flow path 173, and the cross-sectional area of the outlet is formed relatively narrow, so that it is discharged into the gap G through the outlet. The cleaning efficiency of the gap G can be improved by increasing the injection speed of the cleaning liquid F to be used.

The cleaning passage 173 may be continuously formed, but a plurality of cleaning passages 173 having different cross-sectional areas may be connected to each other as shown in FIG. 5 . For example, the cleaning flow path 173 includes a first cleaning flow passage 1732 formed by vertically penetrating the carrier head 100 so as to communicate with the slot 171 , and one side of the cleaning flow passage 1732 is connected to the first cleaning flow passage 1732 . and the other side may include a second cleaning flow path 1731 communicating with the gap G. In this case, the second cleaning passage 1731 may have a smaller cross-sectional area than the first cleaning passage 1732 . Accordingly, the first cleaning passage 1732 receives the cleaning liquid F collected in the slot 171 and flows it into the second cleaning passage 1731 , and the second cleaning passage 1731 receives the cleaning liquid F collected in the slot 171 . It can be discharged through the gap (G) by increasing the flow rate.

Since the gap G between the membrane 140 and the retainer ring 130 is formed to have a very narrow width, conventionally, even if the cleaning liquid F is sprayed from the lower portion of the gap G, the cleaning liquid F is formed in the gap G ), there was a problem that it was not sufficiently introduced into the air and bounced off. Since cleaning is performed by the cleaning liquid F falling along the gap G, the slurry S remaining in the gap G between the membrane 140 and the retainer ring 130 can be effectively removed.

The cleaning liquid supply device 20 may supply the cleaning liquid F to the carrier head 100 . The cleaning liquid supply device 20 may be disposed on the carrier head body 101 . The cleaning liquid supply device 20 may drop the cleaning liquid F from the upper portion of the carrier head main body 101 in the direction of the carrier head main body 101 . The cleaning liquid supply device 20 includes a plurality of spray nozzles, and each of the plurality of spray nozzles may spray the cleaning liquid F through a plurality of inlets 172 formed on the upper portion of the carrier head body 101 .

When the cleaning liquid F is sprayed onto the upper portion of the carrier head body 101 through the spray nozzle, the injection point of the cleaning liquid F to the carrier head body 101 coincides with the inlet 172 of the cleaning flow path 173 . Otherwise, there may be a problem that the sprayed cleaning liquid F is not effectively supplied to the gap G. In addition, as the size of the inlet 172 of the cleaning passage 173 decreases, the supply efficiency of the cleaning liquid F may decrease. In the substrate polishing system according to an embodiment, the carrier head 100 includes a cleaning liquid F sprayed from a spray nozzle of the cleaning liquid supply device 20 through a slot 171 recessed in an upper portion of the carrier head body 101 . The effective carrier head 100 ) can be removed.

7 is an enlarged view of part 'B' of FIG. 5 , and FIGS. 8 to 10 are cross-sectional views of a retainer ring according to an exemplary embodiment.

7 to 10 , the retainer ring 130 according to an exemplary embodiment may include a retainer ring 130 body and a guide protrusion.

The guide protrusion 138 is formed to protrude from the inner surface of the retaining ring body 131, so that the cleaning liquid F supplied to the gap G between the retainer ring 130 and the membrane 140 is evenly spread. can The guide protrusion minimizes the occurrence of an uncleaned area, that is, an area where cleaning is not performed by the cleaning liquid F, in the gap G, and removes the slurry S and foreign substances introduced into the inner surface of the retainer ring 130. can be effectively removed.

The guide protrusion 138 protrudes from the inner surface of the retaining body 131 so as to partially block the gap G formed between the membrane 140 and the retaining body 131 . In this case, between the outer surface of the membrane 140 and the retaining body 131 , a cleaning liquid F passage (DP in FIG. 7 ) having a narrower width than the gap G and through which the cleaning liquid F passes is formed. can be

That is, the guide protrusion 138 may temporarily retain the cleaning liquid F on the inner surface of the retaining ring body 131 . Hereinafter, when the guide protrusion 138 temporarily leaves the cleaning liquid F on the inner surface of the retaining ring body 131 , the cleaning liquid F supplied to the inner surface of the retaining ring body 131 is not discharged immediately. It may be understood as temporarily accumulating, and it may be understood as delaying the time for which the cleaning liquid F stays on the inner surface of the retaining body 131 .

The guide protrusion 138 causes the cleaning liquid F supplied to the inner surface of the retaining body 131 to temporarily remain, so that the cleaning liquid F comes into contact with the outer surface of the membrane 140 and the inner surface of the retaining body 131 . time can be increased. In addition, the guide protrusion 138 causes the cleaning liquid F supplied to the inner surfaces of the retaining ring bodies 131 and 131 to temporarily remain, thereby supplying the cleaning liquid F in a widely spread state on the gap G. Therefore, it is possible to minimize the occurrence of an uncleaned region (a region in which cleaning by the cleaning liquid F is not performed) in the gap G, and advantageous effects of further increasing cleaning efficiency can be obtained.

In particular, when the cleaning liquid F is supplied to the gap G through the plurality of cleaning passages 173 , the plurality of cleaning passages 173 are arranged along the circumferential direction of the retainer ring 130 , and the cleaning liquid ( Since F) is supplied only to the point of the gap G corresponding to each cleaning flow path 173 , a phenomenon in which cleaning by the cleaning liquid F is not sufficiently performed may occur in the area between each cleaning flow path 173 . In this case, the retainer ring 130 widely distributes the cleaning liquid F supplied to the gap G through the guide protrusion 138 , thereby minimizing the occurrence of an uncleaned area in the gap G, and improving cleaning efficiency. can be further improved.

The guide protrusion 138 may be formed in various shapes to temporarily retain the cleaning liquid F flowing into the inner surface of the retaining ring body 131 .

For example, the guide protrusion 138 may be formed in a ring shape on the inner surface of the retaining ring body 131 . When the guide protrusion 138 is formed in a ring shape, it is possible to obtain an effect of uniformly stagnating the cleaning liquid F over the entire area of the gap G.

On the other hand, unlike this, only one guide protrusion 138 may be formed on the inner surface of the retaining body 131 . In some cases, a plurality of guide protrusions 138 may be formed to be spaced apart from each other along the upper and lower "*?*" directions on the inner surface of the retaining ring body 131 .

On the other hand, as shown in FIG. 12 to be described later, a plurality of guide protrusions 138 may be formed to be spaced apart along the circumferential direction of the retaining body 131 or formed in a spiral shape along the inner surface of the retaining ring body 131 . may be

The guide protrusion 138 may include at least one of an upper inclined surface 138a inclined downward toward the membrane 140 and a lower inclined surface 138b inclined upward toward the membrane 140 based on a cross-section. The upper inclined surface 138a may guide the cleaning liquid F supplied to the upper portion of the gap G to the outer surface of the membrane 140 . In this case, the upper inclined surface 138a may be formed in a curved shape as shown in FIG. 7 or may be formed in a flat shape as shown in FIGS. 8 to 10 . The lower inclined surface 138b may guide the cleaning liquid F supplied to the lower portion of the gap G to the outer surface of the membrane 140 . The lower inclined surface 138b may be formed in a curved shape as shown in FIG. 7 or may be formed in a planar shape as shown in FIGS. 8 to 10 .

The guide protrusion 138 may include only one of the upper inclined surface 138a and the lower inclined surface 138b. Alternatively, the guide protrusion 138 may include the upper inclined surface 138a and the lower inclined surface 138b at the same time. The cross-sectional shape of the guide protrusion 138 may vary according to the shape of the upper inclined surface 138a and the lower inclined surface 138b, respectively. For example, the guide protrusion 138 may have a triangular cross-sectional shape having an upper inclined surface 138a and a continuous lower inclined surface 138b as shown in FIG. 10 . On the other hand, unlike this, the guide protrusion 138 may have a trapezoidal cross-sectional shape having an upper inclined surface 138a and a lower inclined surface 138b as shown in FIG. 9 .

In summary, the guide protrusion 138 forms the upper inclined surfaces 138a, 138a and the lower inclined surfaces 138b and 138b, so that the cleaning liquid F introduced into the gap G is transferred to the membranes 140 and 140. ) to increase the time during which the cleaning liquid F contacts the outer surface of the membranes 140 and 140 by guiding toward the outer surface of can be obtained

An upper inclined surface 138a for guiding the cleaning liquid F supplied to the upper portion of the gap G to the outer surface of the membrane 140 may be included. In this case, the upper inclined surface 138a may be formed in a curved shape as shown in FIG. 7 or may be formed in a flat shape as shown in FIGS. 8 to 10 .

11 is a partial cross-sectional view of the carrier head 100 according to an embodiment, and FIG. 12 is a bottom view 130s of the retainer ring 130 according to an embodiment.

11 and 12 , the retainer ring 130 may include a through groove 137a formed in the bottom surface 130s and a connection passage 137b communicating with the through groove 137a.

The through-groove 137a may be radially formed on the bottom surface 130s of the retaining ring body 131 . The through-groove 137a may serve to discharge the slurry S supplied to the polishing pad to the outside of the carrier head 100 along the distal direction of the retaining ring between chemical mechanical polishing processes. A plurality of through grooves 137a may be formed in the retainer ring 130 . The number of the plurality of through grooves 137a and the spacing between the through grooves 137a may be variously changed according to design trends and requirements.

The connection passage 137b may communicate the through-groove 137a and the gap G between the retainer ring 130 and the membrane 140 . The connection passage 137b may have one end connected to the through groove 137a, and the other end connected to the gap G. For example, the connection passage 137b may be vertically depressed in the inner circumferential surface of the retaining ring body 131 . However, unlike this, the connection passage 137b may be formed through the inside of the retaining ring body 131 .

Preferably, the lower end of the connection passage (137b) and the inner end of the through groove (137a) are formed to overlap each other, and the through groove (137a) and the connection passage (137b) are the bottom surface (130s) of the second ring member (134) and continuously connected to the inner circumferential surface to form a groove having an “L” cross-section. At this time, the connection passages 137b and 137b may be formed in a vertical groove shape along the vertical direction on the inner circumferential surface of the second ring members 134 and 134 or may be formed in a groove shape inclined with respect to the vertical direction. .

On the other hand, the lower end of the connecting passage 137b and the inner end of the through groove 137a are formed to completely overlap, so that the lower end of the connecting passage 137b is exposed to the bottom surface 130s of the second ring member 134. It is possible to obtain an advantageous effect of preventing the flatness of the polishing pad 11 from being deteriorated due to the change in the contact area.

In the polishing process, the bottom surface 130s of the second ring member 134 is in direct rotational contact with the soft polishing pad, and the lower end of the connection passage 137b formed on the inner circumferential surface of the second ring member 134 is the second ring. When exposed to the inner side of the bottom surface 130s of the member 134 (the portion of the bottom surface 130s adjacent to the inner circumferential surface of the second ring member 134), the bottom surface 130s of the second ring member 134 has a grooved portion ( The first region, the lower end of the connection passage 137b), and the region where the groove is not formed (the second region) coexist, and the polishing pad is not contacted in the first region and only in the second region. Contact (pressurization) is made. Accordingly, since the polishing pad is pressed only on the portion (second region) of the bottom surface 130s adjacent to the outer circumferential surface among the bottom surfaces 130s of the second ring member 134 , the first first along the radial direction of the second ring member 134 . It is difficult to keep the flatness of the polishing pad constant due to the difference in the pressing area between the region and the second region.

On the other hand, since the through groove 137a is formed entirely along the radial direction on the bottom surface 130s of the second ring member 134, in other words, the area in which the through groove 137a is formed does not contact the polishing pad as a whole. The contact area in the radial direction of the second ring member 134 is maintained constant (the pressing area in the first area and the second area is maintained constant).

As such, the through-groove 137a formed entirely along the radial direction on the bottom surface 130s of the second ring member 134 does not affect the flatness of the polishing pad. By forming the lower end of the connecting passage 137b to overlap with each other, the contact area change (the second for the polishing pad) as the lower end of the connecting passage 137b is exposed to the bottom surface 130s of the second ring member 134. Since the change in the contact area of the ring member 134) can be prevented, an advantageous effect of uniformly maintaining the flatness of the polishing pad can be obtained.

In some cases, it is also possible that the connection passage 137b is formed to partially communicate with the through groove 137a (the lower end of the connection passage 137b overlaps only the inner end of the through groove 137a). The lower end of the connecting passage (137b) is the inner end of the through groove (137a) and the inner end of the through groove (137a) so as to minimize the reduction in polishing uniformity due to the lower end of the passage (137b) being exposed to the bottom surface (130s) of the second ring member (134). It is preferable to form overlapping.

According to this structure, the connection passage 137b is formed on the inner peripheral surface of the second ring member 134 , and the connection passage 137b formed on the inner peripheral surface of the second ring member 134 is connected to the outer surface of the membrane 140 . By communicating with the gap G formed between the inner circumferential surfaces of the retainer rings 130 and 130, a connection passage 137b and An expanded cleaning solution (F) entry path made of a gap (G) is provided.

Accordingly, in the carrier head 100 according to the embodiment, a cleaning solution having an extended width (gap G width + connection passage 137b width) between the outer surface of the membrane 140 and the inner peripheral surface of the retainer ring 130 ). (F) the gap between the membrane 140 and the retainer ring 130 by forming an entry path and allowing the cleaning liquid F to sufficiently flow between the membrane 140 and the retainer ring 130 ( An advantageous effect of effectively removing the slurry (S) remaining in G) can be obtained.

13 is a cross-sectional view of a carrier head according to an embodiment, and FIGS. 14 and 15 are top views of a retaining ring according to an embodiment.

13 to 15 , the retainer ring 130 includes a flat portion FZ formed on the retaining ring body 131 and in contact with the carrier head body 101 , and the retaining ring body 131 formed on the carrier. and a non-flat portion NFZ that is not in contact with the head body 101 .

That is, a flat portion FZ and a non-flat portion NFZ are formed at a portion where the retaining body 131 is coupled to the carrier head body 101 . At this time, the flat portion FZ is in contact with the carrier head body 101 , and the non-flat portion NFZ is not in contact (spaced apart) from the carrier head body 101 .

For reference, in the present invention, the flat portion FZ is defined as a portion that is processed with high processing precision (flatness) and can be flatly adhered to the contact surface (eg, the bottom surface of the carrier head body 101). and the non-flat part NFZ is defined as a region processed with a relatively low processing precision (eg, to the extent that it feels scratchy) to the extent that it is difficult to completely adhere to the contact surface.

The positions at which the flat portion FZ and the non-flat portion NFZ are formed in the retaining body 131 may be variously changed according to required conditions and design specifications. For example, the flat portion FZ and the non-flat portion NFZ are formed on the upper surface of the retaining ring body 131 . In some cases, it is also possible to form the flat portion and the non-flat portion in the extended portion extending from the side surface of the retaining body, or to form the flat portion and the non-flat portion at other positions.

As described above, by forming the flat portion FZ and the non-flat portion NFZ at the portion where the retaining ring body 131 is coupled to the carrier head body 101 , the processing efficiency of the retainer ring 130 is increased and the precision is improved. An advantageous effect of improving can be obtained.

That is, the retainer ring 130 is mounted to be movable up and down with respect to the body portion 110 and the base portion 120 . In order for the bottom surface of the retainer ring 130 to uniformly press the polishing pad 11 , the carrier The installation surface of the retainer ring 130 fixedly installed on the head body 101 should be able to be machined with high processing precision.

However, if the machining precision of the installation surface (eg, upper surface) of the retainer ring 130 in close contact with the carrier head body 101 is low, the installation surface of the retainer ring 130 may be in close contact with the main body 100 . There is a problem in that a deviation in parallelism between the bottom surface of the retainer ring 130 and the polishing pad 11 occurs (the posture of the retainer ring is inclined). In addition, in a state in which the parallelism deviation between the bottom surface of the retainer ring 130 and the polishing pad 11 is generated, even when a uniform pressing force is applied to the upper portion of the retainer ring 130 , the bottom surface of the retainer ring 130 is the polishing pad 11 . There is a problem in that the overall pressure cannot be uniformly applied.

Therefore, in order for the bottom surface of the retainer ring 130 to press the polishing pad 11 uniformly, the installation surface of the retainer ring 130 installed on the carrier head body 101 has high processing precision (high flatness). However, as the entire installation surface of the retainer ring 130 has to be processed with high processing precision, there is a problem in that the production efficiency of the retainer ring 130 is lowered and the manufacturing cost is increased.

However, in the present invention, the flat portion FZ is formed on the installation surface (eg, the upper surface) of the retainer ring 130 in close contact with the carrier head body 101, and the flat portion FZ is lower than the flat portion FZ ( By forming the non-flat portion NFZ having a machining precision), an advantageous effect of increasing the machining efficiency of the retainer ring 130 and improving the precision can be obtained.

Above all, in the entire area of the upper surface of the retaining body 131 , only a part of the flat portion FZ in close contact with the lower surface of the carrier head 100 is processed with high processing precision, and the non-flat non-contacting surface of the carrier head 100 is not in contact with the lower surface of the carrier head 100 . Since it is possible to process the coal portion NFZ with a relatively low processing precision, it is possible to improve the processability and assembling property of the retainer ring 130, improve productivity and yield, and obtain advantageous effects of reducing manufacturing cost. .

Preferably, the non-flat portion NFZ is configured to occupy a larger area than the flat portion FZ in the total area of the upper surface of the retaining body 131 . For example, the non-flat portion NFZ is configured to form 60% or more of the total area of the upper surface of the retaining body 131 . In this way, by forming the non-flat portion NFZ to have a larger area than the flat portion FZ, the precision machining area can be reduced, so that an advantageous effect of further improving the workability and assembling property of the retainer ring 130 is obtained. can

The shape and structure of the flat portion FZ and the non-flat portion NFZ may be variously changed according to required conditions and design specifications, and the present invention is determined by the shape and structure of the flat portion FZ and the non-flat portion NFZ. This is not limited or limited.

For example, referring to FIG. 11 , the non-flat portion NFZ is formed in a continuous ring shape along the circumferential direction of the retaining ring body 131 .

At this time, the flat portion FZ may be formed on both sides of the non-flat portion NFZ along the radial direction of the retaining ring body 131 , respectively. In some cases, it is also possible to form the flat portion on only one side of the flat portion along the radial direction of the retaining body.

In addition, a flat surface UZ to which the flat portion FZ is in close contact is formed on the bottom surface of the carrier head body 101 . In this case, the flat portion FZ and the flat surface UZ are formed to have a high flatness that can be completely in close contact with each other.

As another example, referring to FIG. 12 , the non-flat portion NFZ is formed in a continuous ring shape along the circumferential direction of the retaining body 131 , and a plurality of portions are spaced apart along the radial direction of the retaining body 131 . is formed At this time, the flat portions FZ are alternately formed between the non-flat portions NFZ.

For reference, although the above and illustrated embodiments of the present invention have been described as an example in which the non-flat portion NFZ is formed in a continuous ring shape, according to another embodiment of the present invention, it is spaced apart along the circumferential direction of the retaining ring body. It is also possible to form a plurality of non-flat portions.

For reference, that the non-flat portion NFZ is formed on the upper surface of the retaining body 131 means that the non-flat portion NFZ is recessed or protruded on the upper surface of the retaining body 131 , or the retaining body (131) is defined as including both the upper surface and those formed in a horizontal form.

For example, referring to FIG. 10 , the non-flat portion NFZ is formed to be recessed in the upper surface of the retaining ring body 131 . According to another embodiment of the present invention, it is also possible to form the non-flat portion horizontally with the upper surface of the retaining body, and to form the receiving portion corresponding to the non-flat portion on the bottom surface of the carrier head body.

16 is a cross-sectional view of a carrier head according to an embodiment.

Referring to FIG. 16 , the carrier head body 101 and the retaining body 131 may be fastened to each other by a fastening bolt (B). The fastening bolt (B) may be fastened by a conventional screw fastening method, and the present invention is not limited or limited by the structure and number of the fastening bolt (B).

Preferably, a guide groove is formed to be depressed in the non-flat portion NFZ, and a guide protrusion 103 accommodated in the guide groove is formed to protrude from the bottom surface of the carrier head body 101 .

As described above, by forming a guide groove in the non-flat portion NFZ and allowing the guide protrusion 103 protruding from the bottom surface of the carrier head body 101 to be accommodated, the carrier head body 101 and the retainer ring 130 . It is possible to obtain an advantageous effect of increasing the coupling stability of the carrier head body 101 and suppressing movement in the circumferential direction of the retainer ring 130 with respect to the carrier head body 101 .

In addition, since the lateral flow of the retainer ring 130 with respect to the carrier head body 101 can be constrained by the fastening bolt and the guide protrusion 103 , deformation and unintentional flow of the retainer ring 130 can be prevented. An advantageous effect of effectively suppressing can be obtained.

Furthermore, by allowing the guide protrusion 103 to be accommodated in the guide groove, it absorbs deformation generated when the fastening bolt is fastened to the retainer ring 130 to obtain an advantageous effect of maintaining the planar precision of the retainer ring 130 . can

More preferably, the depth (H1) of the guide groove is formed larger than the protrusion length (H2) of the guide protrusion (103). In this way, by forming the guide groove depth (H1) larger than the protrusion length (H2) of the guide projection (103), it is possible to prevent contact between the guide projection (103) and the retainer ring (130), the guide projection It is not necessary to process the bottom surface of (103) with high processing precision, and advantageous effects of increasing processing efficiency and productivity can be obtained.

17 is a cross-sectional view of a carrier head according to an embodiment.

In the description of FIG. 17, the same or equivalent reference numerals are assigned to the same and equivalent parts as those of the above-described configuration, and detailed description thereof will be omitted.

In the above and illustrated embodiments of the present invention, a guide groove recessed in the non-flat portion NFZ is formed, and a guide protrusion protruding from the bottom surface of the carrier head body 101 is described as an example in which the guide groove is accommodated, In some cases, it is also possible to form a guide projection protruding from the non-flat portion.

For example, referring to FIG. 17 , a receiving groove 103 ′ is recessed in the bottom surface of the carrier head 100 , and the guide protrusion 136 ′ is accommodated in the receiving groove 103 ′ in the non-flat portion NFZ. is formed to protrude.

The guide protrusion 136' is accommodated in the receiving groove 103' and constrains the lateral flow of the retainer ring 130 with respect to the carrier head body 101 together with the fastening bolt (see B of FIG. 13).

As described above, although the embodiments have been described with reference to the limited drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in an order different from the described method, and/or the described components of structures, devices, etc. are combined or combined in a different form than the described method, or other components or equivalents are used. Appropriate results can be achieved even if substituted or substituted by

100: carrier head 101: carrier head body
103: guide projection 110: body part
120: base 130: retainer ring
131: retaining ring body 132: first ring member
134: second ring member 136: guide groove
137a: through groove 137b: connection passage
138: guide projection 140: membrane

Claims (23)

carrier head body;
a membrane connected to the lower side of the carrier head body for pressing the gripped substrate against the polishing pad;
a retainer ring connected to the carrier head body so as to surround an outer surface of the membrane, forming a gap with the membrane, and restraining a side surface of the gripped substrate; and
and a cleaning liquid injection unit formed in the carrier head body and collecting the cleaning liquid falling onto the carrier head body in order to supply the cleaning liquid to the gap.
delete According to claim 1,
The cleaning solution injection unit,
a slot formed in an upper surface of the carrier head body; and
and a cleaning flow passage from the slot passing through the carrier head body and communicating with the gap.
4. The method of claim 3,
The slot is formed on the upper surface of the carrier head body so as to step inward,
The cleaning flow passage communicates with an inlet formed in an inner surface of the slot.
5. The method of claim 4,
Based on the state viewed from the top of the carrier head body,
wherein the inlet has a smaller area than the slot.
5. The method of claim 4,
A plurality of the inlets are formed in the slot,
A plurality of cleaning flow passages are respectively communicated with each of the plurality of inlets.
4. The method of claim 3,
The cleaning flow path,
a first cleaning flow passage formed through the carrier head to communicate with the slot; and
and a second cleaning flow path having one side communicating with the first cleaning flow path, the other side communicating with the gap, and having a cross-sectional area smaller than that of the first cleaning flow path.
4. The method of claim 3,
The cleaning flow path,
A portion communicating with the gap has a smaller cross-sectional area than a portion communicating with the slot.
According to claim 1,
The retainer ring is
and a guide protrusion protruding from the inner surface to face the outer surface of the membrane.
10. The method of claim 9,
The guide projection,
and an upper inclined surface guiding the cleaning liquid supplied to the upper portion of the gap to the outer surface of the membrane.
10. The method of claim 9,
The guide projection,
and a lower inclined surface guiding the cleaning liquid supplied to the lower portion of the gap to the outer surface of the membrane.
10. The method of claim 9,
The guide projection is based on the cross-section,
at least one of an upper sloping surface slanting downward toward the membrane or a lower sloping surface slanting upward toward the membrane.
According to claim 1,
The retaining is
a through-groove formed through the lower surface in a radial direction; and
The carrier head further comprising a connection passage having one end communicating with the through groove and the other end communicating with the gap.
A carrier head for holding a substrate, comprising:
The carrier head,
a slot formed on an upper surface of the carrier head body to collect the cleaning liquid falling onto the upper portion; and
and a cleaning passage for flowing the cleaning liquid collected in the slot downward.
15. The method of claim 14,
The cleaning flow path,
and supplying the cleaning solution to a gap between a membrane for pressing a substrate and a retainer ring surrounding an outer surface of the membrane.
15. The method of claim 14,
The slot is formed to be recessed in an upper surface of the carrier head,
and the cleaning flow passage communicates with an inlet formed in the slot.
a carrier head including a carrier head body, a membrane connected to a lower side of the carrier head body for pressing a substrate against a polishing pad, and a ring-shaped retaining ring connected to the carrier head body to surround an outer surface of the membrane;
and a cleaning liquid supply device disposed at an upper portion of the carrier head body and spaced apart from the carrier head body, and configured to drop the cleaning liquid onto an upper surface of the carrier head body;
The carrier head,
and flowing a cleaning liquid falling from the cleaning liquid supply device into a gap between the retaining ring and the membrane.
18. The method of claim 17,
The carrier head,
a slot recessed in the upper surface of the carrier head body and having an inlet therein; and
and a cleaning flow passage formed through the carrier head body, one side communicating with the inlet and the other side communicating with the outlet formed on the lower surface of the carrier head body to communicate with the gap.
19. The method of claim 18,
and a cross-sectional area of the inlet is greater than a cross-sectional area of the outlet.
delete A carrier head for pressing a substrate to a polishing pad during a chemical mechanical polishing process, comprising:
carrier head body;
a membrane mounted on a lower surface of the carrier head body and pressing the substrate against the polishing pad; and
a retainer ring body disposed to be spaced apart from the outer surface of the membrane, a guide protrusion protruding from an inner surface of the retaining body, and a retainer ring coupled to the carrier head body to constrain a side surface of the substrate; ,
The retaining is
It includes a flat portion and a non-flat portion formed on the upper surface,
wherein the flat portion is in contact with the carrier head body, and the non-planar portion is formed to be spaced apart from and in contact with the carrier head body.
22. The method of claim 21,
Based on the state viewed from the upper surface of the retaining ring,
and the non-flat portion has a larger area than the flat portion.
22. The method of claim 21,
The retaining ring includes a guide groove recessed in the non-flat portion,
The carrier head body protrudes toward a bottom surface and includes an insertion protrusion accommodated in the guide groove.

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