KR20200064000A - Retainer ring in carrier head for chemical mechanical polishing apparatus and carrier head having the same - Google Patents

Abstract

Disclosed are a retainer ring in a carrier head for a chemical mechanical polishing apparatus and a carrier head having the same. According to one embodiment, the carrier head includes: a carrier head main body; a membrane connected to the lower side of the carrier head main body and pressurizing a grasped substrate on a polishing pad; a retainer ring connected to the carrier head main body to surround the outer surface of the membrane, forming a gap with the membrane, and restricting the side surface of the grasped substrate; and a cleaning liquid injecting part formed on the carrier head main body and supplying cleaning liquid into the gap. Therefore, foreign substances remaining in a gap between the retaining ring and the membrane can be effectively removed.

Description

Retainer ring of carrier head for chemical mechanical polishing device and carrier head provided with the same (retainer ring in carrier head for chemical mechanical polishing application

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 slurries and debris flowing 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 flattening that removes the height difference between the cell area and the peripheral circuit area due to unevenness of the wafer surface generated by repeatedly performing masking, etching, and wiring processes during the semiconductor device manufacturing process, and for forming a circuit. This is a device used to precisely polish the surface of the wafer in order to improve the surface roughness of the wafer due to the separation of the contact/wiring film and the highly integrated device.

In such a CMP device, the carrier head presses the wafer to perform a polishing process with the polishing surface of the wafer facing the polishing pad before and after the polishing process, and at the same time, when the polishing process ends, the wafer is directly and indirectly It moves to the next process in the state of holding by vacuum adsorption.

1 and 2, the carrier head 1 has a body portion 110, a base portion 120 rotating with the body portion 110, and a ring shape surrounding the base portion 120, up and down A pressure chamber (C1, C2, C3, C4, C5) in a space between the retainer ring 130 which is movably mounted and rotates together with the base unit 120 and fixed to the base unit 120 and the base unit 120 ) Consists of a membrane 140 made of elastic material and a pressure control unit 150 that regulates 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 is formed by bending the side surface 142 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 to form a suction hole 77 that directly sucks the wafer W. A suction hole is not formed in the central portion of the membrane 150 and may be formed as a surface that presses the wafer W. Between the center of the membrane 140 and the side surface 142, a plurality of ring-shaped partition walls 143 fixed to the base portion 120 are formed, and based on the partition walls 143, a plurality of pressure chambers C1, C2, C3, C4, C5) are arranged in concentric circles.

Accordingly, the pressure chambers C1, C2, C3, C4, and C5 are expanded by pneumatic pressure applied from the pressure regulating unit 150 during the chemical mechanical polishing process, and the wafer W through the membrane bottom plate 141 is expanded. Press the plate surface.

At the same time, the bottom surface 130s of the retainer ring 130 rotating together with the main 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 out 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 main body 110 and the base 120, it ensures the vertical movement of the retainer ring with respect to the membrane fixedly installed in the main body 100 (maintains a non-contact state) ), a gap is formed between the membrane and the retainer ring.

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

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

Thus, in the past, 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 supplied to the gap L1 Due to the fact that the rinsed cleaning solution 15 does not sufficiently spread and escapes as it is, there is a problem 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, in recent years, various studies have been conducted to effectively remove foreign substances (slurry and particles) remaining in the gap between the retainer ring and the membrane, but it is still insufficient to develop them.

An object of the present invention is to provide a retainer ring of a carrier head for a chemical mechanical polishing apparatus and a carrier head having the same, which can effectively remove foreign substances remaining in the gap between the retainer ring and the membrane.

In particular, the present invention aims to enable the cleaning solution supplied between the retainer ring and the membrane to be sufficiently spread, thereby effectively removing the slurry and foreign substances flowing into the inner surface of the retainer ring.

In addition, the present invention is to reduce the cost, and aims to improve the process efficiency and yield.

In addition, the present invention aims to improve stability and reliability and improve precision.

In addition, it is an object of the present invention to improve the processability and assembly of the retainer ring, and to increase the flatness of the retainer ring with respect to the polishing pad.

In addition, it is an object of the present invention to simplify the replacement process of the retainer ring and to 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 costs.

A carrier head according to an embodiment includes a carrier head body; A membrane connected to the lower side of the carrier head body and pressing the gripped substrate against the polishing pad; A retainer ring connected to the carrier head body to surround the outer surface of the membrane, forming a gap with the membrane, and constraining the side surface of the gripped substrate; And it is formed on the carrier head body, it may include a cleaning liquid injection for supplying a cleaning liquid to the gap.

In one side, 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 solution injection portion slot formed on the upper surface of the carrier head body; And a cleaning flow passage penetrating the carrier head body from the slot and communicating with the gap.

In one side, the slot is formed on the upper surface of the carrier head body so as to step inwardly, and the cleaning flow path can communicate with an inlet formed in the inner surface of the slot.

On one side, based on the 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 are formed in the slot, and a plurality of cleaning passages may be respectively communicated with each of the plurality of inlets.

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

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

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

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

In one side, the guide projection may include a lower inclined surface for guiding the cleaning liquid 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 downward toward the membrane or a lower inclined surface inclined upward toward the membrane based on a cross section.

In one side, the retainer ring is a through groove formed through the lower surface in the radial direction; And one end is in communication with the through groove, the other end may further include a connection passage in communication with the gap.

In the carrier head for holding the substrate according to an embodiment, the carrier head, a slot formed on the upper surface to collect the cleaning liquid supplied from the outside; And a cleaning flow path for flowing the cleaning liquid collected in the slot downward.

In one side, the cleaning flow path may supply the cleaning liquid to the gap between the membrane for pressing the substrate and the retainer ring surrounding the outer surface of the membrane.

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

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

The carrier head is disposed on the carrier head main body, and includes a cleaning liquid supply device that drops the cleaning liquid to an upper surface of the carrier head body, and the carrier head is configured to retain the cleaning liquid falling from the cleaning liquid supply device through the retainer and the membrane. It can flow through the gap.

In one side, the carrier head is formed in a recess recessed on the upper surface of the carrier head body and an inlet formed therein; And a cleaning flow path formed through the carrier head body, one side communicating with the inlet, and the other side communicating with an outlet formed on a lower surface of the carrier head body so as to communicate with the gap.

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

A carrier head for pressing a substrate against a polishing pad during a chemical mechanical polishing process according to an embodiment, wherein the carrier head includes a carrier head body; A membrane mounted on the bottom surface of the carrier head body and pressing the substrate against the polishing pad; And a retainer ring body spaced apart from the outer surface of the membrane, and a guide protrusion protruding from the inner surface of the retainer ring body, and a retainer ring coupled to the carrier head body to constrain the side surface of the substrate can do.

In one side, the retainer ring includes a flat portion and a non-flat portion formed on an upper surface, the flat portion is in contact with the carrier head body, and the non-flat portion can be non-contact with the carrier head body.

On one side, based on the state viewed from the upper surface of the retainer ring, the non-flat portion may have a larger area than the flat portion.

In one side, the retainer ring includes a guide groove that is recessed in the non-planar portion, the carrier head body protrudes to the bottom surface, and may include an insertion protrusion 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 retainer ring and the gap of the membrane.

In particular, according to the present invention, by sufficiently purging the cleaning liquid supplied to the inner surface of the retaining body, 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 obtain an advantageous effect of minimizing the generation of a microfine region (a region in which cleaning is not performed by a cleaning liquid) in the gap between the retainer ring and the membrane, and further improving the cleaning efficiency.

In addition, according to the present invention, it is possible to reduce the time and cost for removing the slurry, and it is possible to obtain an advantageous effect of improving process efficiency and yield.

Further, according to the present invention, it is possible to obtain an advantageous effect of improving the processability and assembling property 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 improve the productivity and yield, and obtain an advantageous effect of reducing manufacturing cost.

The following drawings attached to the present specification illustrate one 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, and therefore the present invention is limited to those described in those drawings. It should not be construed as limited.
1 is a cross-sectional view showing a conventional carrier head.
FIG. 2 is an enlarged view of portion'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 an embodiment.
6 is a cross-sectional view of a carrier head according to an embodiment.
7 is an enlarged view of part'B' of FIG. 6.
8 to 10 are cross-sectional views of retainer rings according to an embodiment.
11 is a cross-sectional view of a carrier head according to an embodiment.
12 is a bottom view of a retainer 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 retainer rings according to an 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 through exemplary drawings. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the embodiments, when it is determined that detailed descriptions of related well-known configurations or functions interfere with understanding of the embodiments, detailed descriptions thereof will be omitted.

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

Components included in any one embodiment and components including a common function will be described using the same name in other embodiments. Unless there is an objection to the contrary, the description described in any one embodiment may be applied to other embodiments, and a detailed description will be omitted in the overlapped range.

3 is a schematic view 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 It is a partial cross-sectional view of another carrier head.

3 to 6, the substrate polishing system according to an 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 liquid crystal display (LCD), glass for plasma display device (PDP).

The substrate polishing system can effectively remove foreign substances generated in the polishing process of the substrate W, thereby increasing process efficiency and ensuring polishing uniformity of the substrate W. The substrate polishing system may include a carrier head 100 and a cleaning liquid supply device 20.

The carrier head 100 may grip the substrate W to be polished and make contact with the polishing pad 11. The carrier head 100 is loaded with a substrate W from a cradle (not shown), and a substrate in a state where the slurry S is supplied to the top surface of the polishing pad 11 (not shown) provided on the polishing platen (not shown) Chemical mechanical polishing process may be performed by pressing (W). The carrier head 100 may transfer the substrate W to the cleaning device after the chemical mechanical polishing process using the polishing pad and the slurry S is completed. 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 portion 110 that is connected to a driving shaft (not shown) and rotates, and a base portion 120 that is connected to the main body portion 110 and rotates together.

The body portion 110 is coupled to the top of the drive shaft can be driven to rotate according to the operation of the drive shaft. For reference, in the drawing, the body portion 110 is described as an example formed of a single body, but unlike this, two or more bodies may be combined to constitute a body.

The base portion 120 is disposed to be coaxially aligned with respect to the body portion 110 and may be coupled to the body portion 110 to rotate together with the body portion 110.

The membrane 140 is connected to the lower side of the carrier head body 101 and can press the substrate W to the polishing pad 11. The membrane 140 may be formed of an elastic flexible material. For example, the elastic flexible material may be polyurethane. The membrane 140 includes a circular bottom plate 141 facing the non-abrasive surface of the substrate W, a side surface which is bent from an edge end of the bottom plate 141 and extends in an upper vertical direction, and a bottom plate 141 It may be formed between the center and the side of the, and may include a plurality of partition walls 143 in the form of a ring coupled to the base portion 120. By such a 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 portion 120.

A plurality of pressure chambers C1 to C5 may be provided with pressure sensors for measuring pressure, respectively. Pressure of each pressure chamber (C1 ~ C5) is controlled by the pressure control unit 150, it can be adjusted individually.

The retainer ring 130 is 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 the 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 where the substrate W is gripped on the lower side of the membrane 140, the retainer ring 130 wraps and constrains the side surfaces of the gripped substrate W, thereby preventing the substrate W from deviating from the gripping position between polishing processes. Can be prevented.

The retainer ring 130 may be spaced a predetermined distance from the outer surface of the membrane 140. 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. Therefore, the inner circumferential surface of the retainer ring 130 and the outer surface of the membrane 140 may form a predetermined gap G in a state facing each other.

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

The retainer ring body 131 may be formed in a ring shape. The retainer 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 periphery of the substrate W located under the bottom plate 141 of the membrane 140 during the chemical mechanical polishing process. On the other hand, in the drawing, the case where the retaining body 131 is composed of two parts is illustrated, but it is also possible that the retaining body 131 is formed of a single ring member. Hereinafter, for convenience of description, the case where the retaining 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, engineering plastic or resin.

The retainer ring 130 may move up and down relative to the carrier head body 101 by the pressure of a ring-shaped pressurizing chamber (not shown) located on the upper side. For example, the lower member integrally moving up and down with the retainer ring 130 and the upper member positioned above the lower member and disposed in contact with the upper surface of the lower member, and the circumference of the contact surface of the lower member and the upper member. A pressurizing chamber may be formed by the wrapping flexible ring member. In this case, the degree to which the retainer ring 130 presses the surface of the polishing pad can be controlled while the distance between the lower member and the upper member is adjusted according to the pressure supplied from the pressure control unit 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, a residue G generated from polishing the substrate W and a foreign material such as a slurry S may be introduced into the gap G between the retainer ring 130 and the membrane 140. Foreign matter introduced into the gap G may interfere with the movement of the retainer ring 130 or cause a phenomenon in which the polishing degree of the substrate W is lowered by being attached to the substrate W or the membrane 140 in the polishing process. Can be.

The cleaning liquid injection unit 170 may collect the cleaning liquid F supplied from the outside of the carrier head 100 to flow into the gap G between the membrane 140 and the retainer ring 130. That is, since the cleaning liquid injection unit 170 flows the cleaning liquid F from the upper portion of the gap G in the downward direction, effectively removes foreign substances introduced into the gap G between the retainer ring 130 and the membrane 140. can do.

The cleaning liquid 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 with the gap G from the slot 171.

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 step inward. When the cleaning liquid F is supplied to the upper portion of the carrier head body 101, the cleaning liquid F is introduced into the slot 171, whereby it can be effectively collected.

The cleaning flow passage 173 is formed by penetrating the carrier head body 101 in the vertical direction 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 be in communication with the inlet 172 formed in the slot 171, and the other side may be in communication with an outlet formed on the lower surface of the carrier head body 101 to connect with the gap G. According to this structure, the cleaning liquid F collected in the slot 171 is injected into the cleaning flow path 173 through the inlet 172, flows along the cleaning flow path 173, and flows through the discharge port to the gap G. Can be discharged.

4, the inlet 172 may have a smaller area than the slot 171 based on the state viewed from the top of the carrier head body 101. When the cleaning flow path 173 is formed in the carrier head body 101, the cleaning flow path 173 may be limited to within a certain size. In general, the diameter of the cleaning flow path 173 may be limited to within 5 mm, in this case, a phenomenon that the cleaning liquid F does not efficiently flow 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 first collected in the slot 171, and secondly through the inlet 172 in the slot 171 By supplying the cleaning flow path 173, it is possible to more stably and efficiently flow into the gap G.

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 washing passages may be respectively communicated with each of the plurality of inlets 172. According to such a structure, compared with the case where the cleaning liquid F is supplied to each of the plurality of cleaning flow paths, the cleaning liquid F is first collected in the slot 171 and the inlet 172 in the slot 171 according to its own weight ), since the second flow into each cleaning flow path, the cleaning liquid F may be introduced into the gap G between the retainer ring 130 and the membrane 140 more effectively.

The cleaning flow 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 a portion adjacent to the slot 171. Specifically, the area of the cleaning passage 173 communicating with the gap G, that is, the cross-sectional area of the outlet may be smaller than that of the site communicating with the slot 171, that is, the inlet 172. According to such a structure, the cross-sectional area of the inlet 172 is formed to be wide, so that the cleaning liquid F is effectively supplied to the cleaning flow path 173, while the cross-sectional area of the outlet is relatively narrow to discharge 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.

The cleaning flow passage 173 may be continuously formed, but a plurality of cleaning flow passages 173 having different cross-sectional areas may be connected as shown in FIG. 5. For example, the cleaning flow path 173 is connected to the first cleaning flow path 1732 formed through the carrier head 100 in the vertical direction so as to communicate with the slot 171, and one side is connected to the first cleaning flow path 1732 And the other side may include a second washing flow path (1731) communicating with the gap (G). In this case, the second washing flow path 1173 may have a smaller cross-sectional area than the first washing flow path 1732. Therefore, the first washing flow path 1732 receives the washing liquid F collected in the slot 171 and flows it to the second washing flow path 1173, and the second washing flow path 1173 is the flow of the flowing washing liquid F. By increasing the flow rate, it can be discharged into the gap (G).

Since the gap G between the membrane 140 and the retainer ring 130 is formed with a very narrow width, even if the washing liquid F is sprayed from the lower portion of the gap G, the washing liquid F is the gap G ), the carrier head 100 according to an embodiment supplies the cleaning liquid F from the upper portion of the gap G through the cleaning liquid injection unit 170 in the case of the carrier head 100 according to an embodiment, 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 body 101 toward the carrier head 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 the plurality of inlets 172 formed on the carrier head body 101.

When the cleaning liquid F is sprayed to the top of the carrier head body 101 through the injection 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 If not, the problem that the sprayed cleaning liquid (F) is not effectively supplied to the gap (G) may occur. In addition, the smaller the size of the inlet 172 of the cleaning flow passage 173, the more the supply efficiency of the cleaning liquid F may be reduced. In the substrate polishing system according to an embodiment, the carrier head 100 is the cleaning liquid (F) sprayed from the spray nozzle of the cleaning liquid supply device 20 through the slot 171 formed in the upper portion of the carrier head body 101 The effective carrier head 100 is collected and collected, and the collected cleaning liquid F is supplied to the gap G between the retainer ring 130 and the membrane 140 through the cleaning flow path 173 formed in the slot 171. ) Can remove foreign matters.

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 embodiment.

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

The guide projection 138 is formed to protrude on the inner surface of the retainer ring body 131, so that the cleaning liquid F supplied to the gap G between the retainer ring 130 and the membrane 140 spreads evenly. Can be. The guide protrusion minimizes the generation of a microfine region in the gap G, that is, a region in which cleaning is not performed by the cleaning liquid F, and the slurry S and foreign substances introduced into the inner surface of the retainer ring 130 are minimized. It can be effectively removed.

The guide protrusion 138 protrudes on the inner surface of the retaining body 131 to partially close 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 retainer body 131 has a narrower width than the gap G, and the cleaning fluid F through which the cleaning fluid F passes (DP in FIG. 7) is formed. Can be.

That is, the guide protrusion 138 may temporarily retain the cleaning liquid F on the inner surface of the retaining body 131. Hereinafter, that the guide projection 138 temporarily retains the cleaning liquid F on the inner surface of the retaining body 131 means that the cleaning liquid F supplied to the inner surface of the retaining body 131 is not immediately discharged. It may be understood to temporarily accumulate, and may be understood to delay the time that 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 remain temporarily, so that the cleaning liquid F contacts the outer surface of the membrane 140 and the inner surface of the retaining body 131. It can increase the time to do. In addition, the guide projection 138 is supplied to the cleaning liquid (F) in a wide spread state on the gap (G) by allowing the cleaning liquid (F) supplied to the inner surface of the retaining body (131, 131) to remain temporarily. Since it can be guided, it is possible to obtain an advantageous effect of minimizing the generation of the microfine region (the region in which cleaning is not performed by the cleaning liquid F) in the gap G and further improving the cleaning efficiency.

Particularly, when the cleaning liquid F is supplied to the gap G through the plurality of cleaning flow paths 173, the plurality of cleaning flow paths 173 are arranged along the circumferential direction of the retainer ring 130. Since F) is supplied only to the gap G corresponding to each cleaning flow passage 173, a phenomenon in which cleaning by the cleaning liquid F is not sufficiently performed in the region between each cleaning flow passage 173 may occur. 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 a microfine region in the gap G and cleaning efficiency. It can improve more.

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

For example, the guide protrusion 138 may be formed in a ring shape on the inner surface of the retainer 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.

Meanwhile, 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 on the inner surface of the retaining body 131 along the vertical direction "*?*".

On the other hand, the guide protrusion 138 is formed to be spaced apart a plurality along the circumferential direction of the retainer body 131, as shown in FIG. 12 to be described later, or to be formed in a spiral shape along the inner surface of the retainer body 131 It might be.

The guide protrusion 138 may include at least one of an upper inclined surface 138a inclined downward toward the membrane 140 or a lower inclined surface 138b inclined upward toward the membrane 140 based on the 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 illustrated 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 form as shown in FIG. 7 or may be formed in a planar form as illustrated 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, but may alternatively include the upper inclined surface 138a and the lower inclined surface 138b at the same time. The cross-sectional shape of the guide projection 138 may be changed according to the shape of each of the upper inclined surface 138a and the lower inclined surface 138b. For example, the guide projection 138 may have a triangular cross-sectional shape having an upper inclined surface 138a and a 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 projection 138 is formed by forming the upper inclined surface (138a) (138a) and the lower inclined surface (138b) (138b), the cleaning solution (F) flowing into the gap (G) membrane 140 (140) ) By guiding toward the outer surface of the cleaning solution (F) can increase the time to contact the outer surface of the membrane 140, 140, the cleaning effect by the cleaning solution (F) and the advantageous effect of improving the cleaning efficiency Can be obtained.

It may include 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). 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 illustrated in FIGS. 8 to 10.

11 is a partial cross-sectional view of a 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 formed in the radial direction on the bottom surface 130s of the retaining body 131. The through groove 137a may perform a function of discharging the slurry S supplied to the polishing pad between the chemical and mechanical polishing processes to the outside of the carrier head 100 along the original direction of the retaining ring. 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 musks and requirements.

The connection passage 137b may communicate a gap G between the through groove 137a and 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 recessed in the vertical direction on the inner circumferential surface of the retainer body 131. However, unlike this, the connection passage 137b may be formed through the inside of the retainer body 131.

Preferably, the lower end of the connecting passage 137b and the inner end of the through groove 137a are formed to overlap each other, and the through groove 137a and the connecting 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 groove shape perpendicular to the inner circumferential surface of the second ring members 134 and 134, or in an inclined groove shape in the vertical direction. .

On the other hand, unlike this, the lower end of the connecting passage 137b and the inner end of the through groove 137a are formed to overlap completely, 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 lowered by the change in the contact area according to.

In the polishing process, the bottom surface 130s of the second ring member 134 is in direct rotary 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 inside of the bottom surface 130s of the member 134 (a portion of the bottom surface 130s adjacent to the inner circumferential surface of the second ring member 134), a grooved portion is formed on the bottom surface 130s of the second ring member 134 ( The first region, the lower end of the connection passage 137b), and the portion where the groove is not formed (the second region) coexist, and in the first region, no contact with the polishing pad is made, and the polishing pad is only in the second region. The contact (pressing) is made. Therefore, since the polishing pad is pressed only at a 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 along the radial direction of the second ring member 134 It is difficult to maintain the flatness of the polishing pad constant due to the difference in the pressing area in the region and the second region.

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

As described above, based on the fact that the through grooves 137a formed as a whole along the radial direction on the bottom surface 130s of the second ring member 134 do not affect the flatness of the polishing pad, on the through grooves 137a region By forming the lower end of the connecting passage 137b to overlap, the contact area change due to the lower end of the second connecting member 134 being exposed to the bottom surface 130s of the second ring member 134 (second to the polishing pad) Since it is possible to prevent the change in the contact area of the ring member 134), an advantageous effect of uniformly maintaining the flatness of the polishing pad can be obtained.

In some cases, the connection passage 137b may be formed to partially communicate with the through groove 137a (the lower end of the connection passage 137b overlaps only partially with the inner end of the through groove 137a). The lower end of the connecting passage 137b can be minimized with the inner end of the through groove 137a so as to minimize a decrease in polishing uniformity due to exposure of the lower end of the passage 137b to the bottom 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 circumferential surface of the second ring member 134, and the connection passage 137b formed on the inner circumferential surface of the second ring member 134 is in contact with 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 is provided between the outer surface of the membrane 140 and the inner circumferential surface of the retainer ring 130. A path for entering the extended cleaning liquid F made of the gap G is provided.

Therefore, the carrier head 100 according to the embodiment is a cleaning solution having an expanded width (gap (G) width + connecting passage (137b) width) between the outer surface of the membrane 140 and the inner circumferential 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 solution F to sufficiently flow between the membrane 140 and the retainer ring 130. The 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 retainer rings according to an embodiment.

13 to 15, the retainer ring 130 is formed on the retainer ring body 131 and is formed on the flattening part FZ contacting the carrier head body 101 and the retainer ring body 131 and the carrier It includes 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 retainer 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 in non-contact (spaced) with the carrier head body 101.

For reference, in the present invention, the flat part (FZ) is defined as a part that is processed with high processing precision (flatness) and can be in close contact with the surface to be contacted (for example, the bottom surface of the carrier head body 101). In addition, the non-flat part (NFZ) is defined as a part that is processed with a relatively low processing precision (for example, a feeling of tingling) that is difficult to completely adhere to a contact surface.

The position where 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 body 131. In some cases, it is also possible to form a flat portion and a non-flat portion in an extended portion extending on the side surface of the retaining body, or to form a flat portion and a non-flat portion in other positions.

In this way, by forming the flat portion (FZ) and the non-flat portion (NFZ) in the portion where the retainer ring body 131 is coupled to the carrier head body 101, the processing efficiency of the retainer ring 130 is increased and accuracy 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, the bottom surface of the retainer ring 130 to uniformly press the polishing pad 11, the carrier The mounting surface of the retainer ring 130 fixedly installed on the head body 101 should be able to be processed with high machining precision.

However, if the processing precision of the mounting surface (for example, the upper surface) of the retainer ring 130 in close contact with the carrier head body 101 is low, the mounting 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 the parallelism between the bottom surface of the retainer ring 130 and the polishing pad 11 occurs (the attitude of the retainer ring is inclined). In addition, in a state in which a parallelism deviation between the bottom surface of the retainer ring 130 and the polishing pad 11 occurs, 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 has a polishing pad 11 There is a problem that can not be uniformly pressurized as a whole.

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). Although it should be possible, as the entire installation surface of the retainer ring 130 needs to be processed with high processing precision, there is a problem that the production efficiency of the retainer ring 130 decreases and manufacturing cost increases.

However, the present invention forms a flat portion FZ on the installation surface (for example, the top surface) of the retainer ring 130 that is in close contact with the carrier head body 101, and also has a lower flatness than the flat portion FZ ( By forming the non-planar portion NFZ having the processing precision), it is possible to obtain an advantageous effect of increasing the processing efficiency of the retainer ring 130 and improving the precision.

Above all, only a portion of the flat portion (FZ) area in close contact with the bottom surface of the carrier head 100 in the entire area of the upper surface of the retaining body 131 is processed with high processing accuracy, and criticism non-contacting the bottom surface of the carrier head 100 Since the carbon part NFZ can be processed with a relatively low processing precision, it is possible to improve the processability and assemblability of the retainer ring 130, improve productivity and yield, and obtain an advantageous effect of reducing manufacturing cost. .

Preferably, the non-planar portion NFZ is configured to occupy a larger area than the flat portion FZ in the entire area of the upper surface of the retaining body 131. For example, the non-planar portion NFZ is configured to form 60% or more of the total area of the upper surface of the retaining body 131. As described above, by forming the non-planar portion NFZ with a larger area than the flat portion FZ, the precision machining portion can be reduced, thereby obtaining an advantageous effect of further improving the processability and assembling property of the retainer ring 130. Can be.

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 provided by the shape and structure of the flat portion (FZ) and the non-flat portion (NFZ). It is not limited or limited.

For example, referring to FIG. 11, the non-planar portion NFZ is formed in a continuous ring shape along the circumferential direction of the retainer 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 body 131. In some cases, it is also possible to form the flat portion only on one side of the flat portion along the radial direction of the retaining body.

In addition, a flat surface UZ to which the flat part FZ is closely formed is formed on the bottom surface of the carrier head body 101. At this time, the flat portion FZ and the flat surface UZ are formed to have a high flatness that can be completely adhered to.

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

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

For reference, that the non-planar portion NFZ is formed on the upper surface of the retaining body 131 is that the non-flat portion NFZ is formed in a recessed or protruding shape on the upper surface of the retaining body 131, or the retaining body It is defined as including all formed in a horizontal shape with the upper surface of (131).

For example, referring to FIG. 10, the non-planar portion NFZ is formed to be recessed on the upper surface of the retaining 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 retainer body, and to form a 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.

16, the carrier head body 101 and the retainer body 131 may be fastened by a fastening bolt (B). The fastening bolt (B) can be fastened by a conventional screw fastening method, and the present invention is not limited or limited by the structure and number of fastening bolts (B).

Preferably, a guide groove is formed to be recessed in the non-flat part NFZ, and a guide protrusion 103 accommodated in the guide groove is protruded on the bottom surface of the carrier head body 101.

In this way, by forming a guide groove in the non-flat part NFZ, and by allowing the guide projection 103 protruding to the bottom surface of the carrier head body 101 to be received, the carrier head body 101 and the retainer ring 130 To increase the bonding stability of, it is possible to obtain an advantageous effect of suppressing the movement of the circumferential direction of the retainer ring 130 with respect to the carrier head body 101.

In addition, since the transverse 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, the deformation of the retainer ring 130 and unintended flow can be seen. An advantageous effect of effectively suppressing can be obtained.

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

More preferably, the depth (H1) of the guide groove is formed larger than the protruding length (H2) of the guide projection (103). In this way, by forming the depth (H1) of the guide groove larger than the protruding length (H2) of the guide projection 103, it is possible to prevent the contact between the guide projection 103 and the retainer ring 130, the guide projection There is no need to process the bottom surface of (103) with high processing precision, and an advantageous effect 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 given to the same and equivalent parts as the above-described configuration, and detailed description thereof will be omitted.

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

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

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

Although the embodiments have been described by the limited drawings as described above, a person skilled in the art can make various modifications and variations from the above description. For example, the described techniques may be performed in a different order than the described method, and/or components such as the structure, device, etc. described may be combined or combined in a different form from the described method, or may be applied to other components or equivalents. Even if replaced or substituted by, appropriate results can be achieved.

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

Claims (23)

A carrier head body;
A membrane connected to the lower side of the carrier head body and pressing the gripped substrate against the polishing pad;
A retainer ring connected to the carrier head body to surround the outer surface of the membrane, forming a gap with the membrane, and constraining the side surface of the gripped substrate; And
A carrier head formed on the carrier head body and including a cleaning liquid injection part for supplying a cleaning liquid to the gap.
According to claim 1,
The cleaning solution injection unit,
A carrier head that collects the cleaning liquid falling to the upper portion of the carrier head body and flows the gap.
According to claim 2,
The cleaning solution injection unit,
A slot formed on an upper surface of the carrier head body; And
And a cleaning flow passage penetrating the carrier head body from the slot and communicating with the gap.
According to claim 3,
The slot is formed on the upper surface of the carrier head body so as to step inwardly,
The cleaning flow path is in communication with the inlet formed on the inner surface of the slot, the carrier head.
The method of claim 4,
Based on the state viewed from the top of the carrier head body,
The inlet is smaller than the slot, the carrier head.
The method of claim 4,
A plurality of the inlets are formed in the slot,
A carrier head in which a plurality of cleaning passages are respectively communicated with each of the plurality of inlets.
According to claim 3,
The washing flow path,
A first cleaning flow path formed through the carrier head so as to communicate with the slot; And
One side communicates with the first cleaning flow path, the other side communicates with the gap, and includes a second cleaning flow path having a smaller cross-sectional area than the first cleaning flow path.
According to claim 3,
The washing flow path,
The carrier head having a smaller cross-sectional area than the portion communicating with the slot, the portion communicating with the gap.
According to claim 1,
The retainer ring,
A carrier head including a guide protrusion protruding from the inner surface to face the outer surface of the membrane.
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.
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.
The method of claim 9,
The guide projection is based on the cross section,
And at least one of an upper inclined surface inclined downward toward the membrane or a lower inclined surface inclined upward toward the membrane.
According to claim 1,
The retainer ring,
A through groove formed through the lower surface along the radial direction; And
One end is in communication with the through groove, the other end further comprises a connecting passage in communication with the gap, the carrier head.
In the carrier head for holding the substrate,
The carrier head,
A slot formed on an upper surface to collect the cleaning liquid supplied from the outside; And
A carrier head including a cleaning flow path for flowing the cleaning liquid collected in the slot downward.
The method of claim 14,
The washing flow path,
A carrier head for supplying the cleaning liquid to a gap between a membrane for pressing the substrate and a retainer ring surrounding the outer surface of the membrane.
The method of claim 14,
The slot is recessed stepwise on the upper surface of the carrier head,
The cleaning flow path is in communication with the inlet formed in the slot, the carrier head.
A carrier head including a carrier head body, a membrane connected to a lower side of the carrier head body and pressing the substrate against the polishing pad; and a ring-shaped retainer ring connected to the carrier head body to surround the outer surface of the membrane;
It is disposed on the carrier head body, and includes a cleaning liquid supply device for dropping the cleaning liquid to the upper surface of the carrier head body,
The carrier head,
A substrate polishing system for flowing cleaning liquid falling from the cleaning liquid supplying device into a gap between the retainer ring and the membrane.
The method of claim 17,
The carrier head,
A slot formed in the upper surface of the carrier head body and recessed therein; And
And a cleaning flow path formed through the carrier head body, one side communicating with the inlet, and the other side communicating with an outlet formed on a lower surface of the carrier head body so as to communicate with the gap.
The method of claim 18,
The substrate polishing system, wherein the cross-sectional area of the inlet is larger than the cross-sectional area of the outlet.
As a carrier head for pressing the substrate against the polishing pad during the chemical mechanical polishing process,
A carrier head body;
A membrane mounted on the bottom surface of the carrier head body and pressing the substrate against the polishing pad; And
It includes a retainer ring body spaced apart from the outer surface of the membrane, and a guide protrusion protruding from the inner surface of the retainer ring body, and a retainer ring coupled to the carrier head body to constrain the side surface of the substrate , Carrier head. The method of claim 20,
The retainer ring
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-flat portion is non-contact with the carrier head body.
The method of claim 21,
Based on the state viewed from the top surface of the retainer ring,
The non-flat portion has a larger area than the flat portion, the carrier head.
The method of claim 21,
The retainer ring includes a guide groove that is recessed in the non-flat portion,
The carrier head body protrudes to the bottom surface, and includes an insertion protrusion accommodated in the guide groove, the carrier head.

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