Polishing head system and polishing method

Abstract

To provide a polishing head system that can precisely control a polishing rate for a substrate such as a wafer, and a polishing rate at an edge part in particular.SOLUTION: A polishing head system 1 is provided with a polishing head 10, a head shaft 11, a head rotating mechanism 18, a multi-path rotary joint 25, a liquid supply line Lb1, and a pressure regulator Rb1. The polishing head 10 has a substrate pressing surface 35, a retainer ring 40, and a plurality of pressure chambers Cb1-Cb6 arranged along a circumferential direction of the retainer ring 40. The head shaft 11 has a plurality of shaft flow paths 56 communicated with the plurality of pressure chambers Cb1-Cb6 respectively. The multi-path rotary joint 25 is configured to sequentially communicate the fluid supply line Lb1 with the plurality of shaft flow paths 56, every time when the head shaft 11 rotates once.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a polishing head system and method for polishing substrates, such as wafers. [Background technology]

[0002] In recent years, with the increasing integration and density of semiconductor devices, the wiring of circuits has become finer and the number of layers in multilayer wiring has also increased. When attempting to realize multilayer wiring while miniaturizing circuits, the step becomes larger while following the surface unevenness of the lower layer, and as the number of wiring layers increases, the film coverage (step coverage) for the step shape in thin film formation deteriorates. Therefore, in order to realize multilayer wiring, this step coverage must be improved and planarization processing must be performed in the appropriate process. In addition, as the depth of focus becomes shallower with the miniaturization of optical lithography, it is necessary to planarize the surface of the semiconductor device so that the unevenness and step on the surface of the semiconductor device are contained within the depth of focus.

[0003] Therefore, in the manufacturing process of semiconductor devices, planarization of the semiconductor device surface is becoming more and more important. The most important technology for planarizing the surface is chemical mechanical polishing (CMP). This chemical mechanical polishing (hereinafter referred to as CMP) is performed by supplying a polishing liquid (e.g., a slurry containing abrasive grains) such as silica (SiO2) onto the polishing surface of a polishing pad while sliding a substrate such as a wafer against the polishing surface.

[0004] A polishing apparatus for carrying out CMP includes a polishing table that supports a polishing pad having a polishing surface, and a polishing head (substrate holding device) that holds a substrate. Polishing of a substrate using such a polishing apparatus is carried out as follows. A polishing liquid is supplied onto the polishing pad while rotating the polishing table together with the polishing pad. The polishing head presses the substrate against the polishing surface of the polishing pad while rotating the substrate. While the substrate is brought into sliding contact with the polishing pad in the presence of the polishing liquid, the surface of the substrate is planarized by a combination of the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad.

[0005] If the relative pressure between the substrate and the polishing surface of the polishing pad during polishing is not uniform over the entire surface of the substrate, insufficient polishing or overpolishing occurs depending on the pressure applied to each part of the substrate. Therefore, in order to equalize the pressure applied to the substrate, a pressure chamber formed of an elastic membrane is provided under the polishing head, and a fluid such as air is supplied to the pressure chamber to press the substrate by the fluid pressure via the elastic membrane.

[0006] Since the polishing pad has elasticity, the pressing force applied to the edge (periphery) of the substrate during polishing becomes uneven, and the edge of the substrate is polished more than the other parts, which may cause so-called "edge rounding". In order to prevent such edge rounding and to prevent the substrate from jumping out of the polishing head during polishing, a polishing head equipped with a retainer ring is used. This retainer ring is arranged to surround the substrate, and while the substrate is being polished, the retainer ring rotates and presses the polishing pad against the outside of the substrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-4675 A [Patent Document 2] JP 2015-233131 A [Patent Document 3] JP 2020-104200 A Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, the variety of semiconductor devices has increased dramatically, and there is an increasing need to adjust the polishing rate at the edge of the substrate for each device and each CMP process (oxide film polishing, metal film polishing, etc.). One of the reasons for this is that the film formation process performed before each CMP process varies depending on the type of film, and the initial film thickness distribution of the substrate varies depending on the film formation process. Normally, a substrate after CMP is required to have a uniform film thickness distribution over its entire surface, so the polishing rate needs to be adjusted according to the initial film thickness distribution.

[0009] Another reason is that the types of polishing pads and polishing liquids used in polishing devices are increasing from the viewpoint of cost, etc. Different types of consumables such as polishing pads and polishing liquids can significantly change the initial film thickness distribution, especially at the edge of the substrate. In semiconductor device manufacturing, the variation in film thickness at the edge of the substrate significantly affects the product yield, so it is very important to precisely adjust the polishing rate at the edge of the substrate.

[0010] As described above, a polishing head equipped with a retainer ring has been used in the past. It is possible to adjust the polishing rate of the edge portion of the substrate by adjusting the pressing force applied to the retainer ring. However, when the pressing force applied to the retainer ring is changed, the polishing rate changes not only at the edge portion of the substrate but also over a relatively wide range including other regions. Therefore, this method is not suitable when it is desired to precisely control the polishing profile at the edge portion of the substrate.

[0011] Patent Document 1 describes a method of applying a local load to a part of a retaining ring by using a local load applying mechanism. However, such a local load applying mechanism has problems such as the need to prevent the intrusion of liquid used in the polishing apparatus and the generation of particles. [Means for solving the problem]

[0012] As a result of various experiments, the inventors discovered that the polishing rate at the edge portion of the substrate can be precisely controlled by changing the pressing force applied to the retaining ring that holds the edge portion of the substrate in the circumferential direction.

[0013] SUMMARY OF THE PRESENT EMBODIMENTS It is therefore an object of the present invention to provide a polishing head system and a polishing method that are capable of precisely controlling the polishing rate of a substrate such as a wafer, particularly the polishing rate at an edge portion.

[0014] In one aspect, a polishing head system is provided, comprising: a polishing head that presses a substrate against a polishing surface; a head shaft connected to the polishing head; a head rotation mechanism that rotates the polishing head together with the head shaft; a multi-pass rotary joint arranged to surround at least a portion of the head shaft; a fluid supply line connected to the multi-pass rotary joint; and a pressure regulator attached to the fluid supply line, wherein the polishing head has a substrate pressing surface that presses the substrate against the polishing surface; a retaining ring arranged to surround the substrate pressing surface; and a plurality of pressure chambers formed of an elastic material and generating a pressing force for pressing the retaining ring against the polishing surface, the head shaft has a plurality of shaft flow paths that respectively communicate with the plurality of pressure chambers, the multi-pass rotary joint is configured to sequentially communicate the fluid supply line with the plurality of shaft flow paths each time the head shaft rotates once, and the plurality of pressure chambers are arranged along the circumferential direction of the retaining ring.

[0015] In one aspect, the multiple shaft flow passages have multiple shaft openings that open on the outer surface of the head shaft, the multi-path rotary joint has the joint flow passage communicating with the fluid supply line, the joint flow passage has a joint opening that opens on the inner surface of the multi-path rotary joint, the multiple shaft openings are arranged along the circumferential direction of the head shaft, and the multiple shaft openings and the joint opening are at the same position in the axial direction of the head shaft. In one aspect, the fluid supply line is a plurality of fluid supply lines, the pressure regulator is a plurality of pressure regulators respectively attached to the plurality of fluid supply lines, the joint flow passage is a plurality of joint flow passages respectively communicating with the plurality of fluid supply lines, and the joint opening is a plurality of joint openings arranged along a circumferential direction of the head shaft. In one embodiment, the multi-path rotary joint has a joint member arranged circumferentially around the head shaft, a joint holder arranged to surround the joint member, and a spring that presses the joint member against the head shaft, and the joint flow path extends through the joint member and the joint holder. In one aspect, the multi-path rotary joint has a positioning mechanism that fixes a relative position of the joint member with respect to the joint holder in a circumferential direction.

[0016] In one aspect, the multiple pressure chambers are multiple pressure chamber groups, each of which is connected to the multiple shaft flow paths, and each of the multiple pressure chamber groups includes a multiple pressure chambers formed by a multiple rolling diaphragms arranged along a circumferential direction of the retaining ring. In one aspect, each of the plurality of rolling diaphragms has a cylindrical shape. In one aspect, the polishing head further includes an annular pressure chamber adjacent to the plurality of pressure chambers. In one aspect, a width of the joint opening is greater than a width of the shaft openings.

[0017] In one aspect, the polishing head system further includes an operation control unit that controls the operation of the pressure regulator, wherein the multiple pressure chambers include a first pressure chamber, and the operation control unit is configured to send a correction set pressure value that is greater than a set pressure value of the fluid in the fluid supply line to the pressure regulator when the pressure in the first pressure chamber is smaller than a target pressure, thereby causing the pressure regulator to correct the pressure in the first pressure chamber. In one embodiment, the operation control unit is configured to determine the corrected set pressure value that minimizes the difference between the integral value of the pressure in the first pressure chamber during one rotation of the polishing head and the integral value of the target pressure. In one embodiment, the polishing head system further includes a pressure sensor that measures the pressure in the first pressure chamber, and the operation control unit is configured to determine the corrected set pressure value that minimizes the difference between the pressure in the first pressure chamber measured by the pressure sensor and the target pressure. In one embodiment, the operation control unit is configured to determine the corrected set pressure value that minimizes the difference between the pressure in the first pressure chamber and the target pressure based on a correlation between the set pressure value acquired in advance and the pressure in the first pressure chamber.

[0018] In one aspect, a method for polishing a substrate using the above-mentioned polishing head system is provided, comprising: polishing the substrate by pressing the substrate against the polishing surface while rotating the substrate; and, each time the head shaft rotates once during polishing of the substrate, supplying fluid to the multiple pressure chambers through the fluid supply line while sequentially connecting the fluid supply line to the multiple shaft flow paths, thereby applying multiple pressing forces to the retaining ring and pressing the retaining ring against the polishing surface, wherein the multiple pressing forces include at least two different pressing forces. In one embodiment, the polishing of the substrate is performed while rotating the polishing surface, and the pressure regulator adjusts the pressures in the multiple pressure chambers so that the pressing force generated by a pressure chamber that is located downstream in the direction of rotation of the polishing surface is greater than the pressing forces generated by the other pressure chambers.

[0019] In one embodiment, the polishing method further includes, when a pressure in a first pressure chamber included in the plurality of pressure chambers is lower than a target pressure, the pressure regulator corrects the pressure in the first pressure chamber based on a corrected set pressure value that is higher than a set pressure value of the fluid in the fluid supply line. In one embodiment, the polishing method further includes determining the corrected set pressure value that minimizes a difference between an integral value of the pressure in the first pressure chamber during one rotation of the polishing head and an integral value of the target pressure. In one embodiment, the polishing method further includes measuring a pressure in the first pressure chamber with a pressure sensor, and determining the corrected set pressure value that minimizes a difference between the pressure in the first pressure chamber measured by the pressure sensor and the target pressure. In one embodiment, the polishing method further includes determining the corrected set pressure value that minimizes a difference between the pressure in the first pressure chamber and the target pressure, based on a correlation between the set pressure value and the pressure in the first pressure chamber, which has been previously acquired. Effect of the Invention

[0020] According to the present invention, by using a multi-pass rotary joint to apply at least two different pressing forces along the circumferential direction of the retaining ring, it is possible to precisely control the polishing rate at the edge portion of the substrate. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram illustrating an embodiment of a polishing apparatus. [Diagram 2] 1 is a cross-sectional view showing a schematic diagram of an embodiment of a polishing head system. [Diagram 3]FIG. 13 is a top view of one embodiment of a septum and a retaining ring pushing membrane. [Figure 4] FIG. 2 is a top view illustrating a multi-path rotary joint. [Diagram 5] 4 is a cross-sectional view of the rotary joint assembly shown in FIG. 3 taken along line AA. [Figure 6] 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 7] FIG. 1 illustrates an exploded view of one embodiment of a multi-pass rotary joint. [Figure 8] FIG. 8 is an enlarged cross-sectional view of the multi-path rotary joint shown in FIG. [Figure 9] 9 is a cross-sectional view taken along line CC in FIG. 8. [Figure 10] FIG. 2 is an enlarged cross-sectional view showing one embodiment of a positioning mechanism. [Figure 11] 13 is a diagram showing a plurality of pressure regions indicating positions at which the pressing forces generated by a plurality of pressure chambers on a plurality of regions of the retaining ring are switched; FIG. [Figure 12] 11 is a graph showing an embodiment of the progress of pressure in one pressure chamber as the polishing head rotates. [Figure 13] 10 is a graph showing another embodiment of the progress of pressure in one pressure chamber that changes with rotation of the polishing head. [Figure 14] FIG. 11 is an exploded view showing another embodiment of the multi-path rotary joint. [Figure 15] FIG. 15 is a cross-sectional view of the multi-path rotary joint shown in FIG. [Figure 16] FIG. 13 is a schematic diagram showing another embodiment of the polishing head. [Figure 17] FIG. 17 is a cross-sectional view of the rolling diaphragm shown in FIG. 16. [Figure 18] 13 is a schematic diagram showing still another embodiment of the polishing head. FIG. [Figure 19] 19 is a cross-sectional view taken along line DD of the rotary joint assembly shown in FIG. 18. [Figure 20]19 is a cross-sectional view of the rolling diaphragm and the annular rolling diaphragm shown in FIG. 18. [Figure 21] 11 is a graph for explaining the difference in the transition of pressure in one pressure chamber depending on the rotation speed of the polishing head. [Figure 22] 11 is a cross-sectional view showing a schematic diagram of another embodiment of a polishing head system. FIG. [Diagram 23] 1 is a graph illustrating one embodiment of a target pressure, a corrected setpoint pressure value sent to a pressure regulator, and a corrected pressure in one pressure chamber. [Figure 24] 13 is a diagram for explaining an integral value of a target pressure and an integral value of a pressure in a pressure chamber. FIG. [Diagram 25] 13 is a graph showing another example of the target pressure and the corrected set pressure value sent to the pressure regulator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing one embodiment of a polishing apparatus. The polishing apparatus is an apparatus for polishing a substrate W such as a wafer. As shown in FIG. 1, the polishing apparatus includes a polishing head system 1, a polishing table 3 supporting a polishing pad 2, a polishing liquid supply nozzle 5 supplying a polishing liquid (e.g., a slurry containing abrasive grains) to the polishing pad 2, a table motor 6 rotating the polishing table 3 together with the polishing pad 2, and a film thickness sensor 7 acquiring a film thickness signal that changes according to the film thickness of the substrate W. The film thickness sensor 7 is installed in the polishing table 3, and acquires film thickness signals in a plurality of regions including the center of the substrate W every time the polishing table 3 rotates once. Examples of the film thickness sensor 7 include an optical sensor and an eddy current sensor.

[0023] The polishing pad 2 is attached to the upper surface of the polishing table 3. The exposed surface of the polishing pad 2 constitutes a polishing surface 2a for polishing a substrate W such as a wafer. The table motor 6 is disposed below the polishing table 3. The polishing table 3 is connected to the table motor 6 via a table shaft 3a. The polishing table 3 and the polishing pad 2 are rotated by the table motor 6 about the axis of the table shaft 3a.

[0024] The polishing head system 1 includes a polishing head (substrate holding device) 10 that presses a substrate W such as a wafer against the polishing surface 2a of the polishing pad 2, a head shaft 11 connected to the polishing head 10, a head swing shaft 14, a head swing arm 16 connected to the upper end of the head swing shaft 14, and a rotary joint assembly 20 attached to the upper part of the head shaft 11. The polishing head 10 is fixed to the lower end of the head shaft 11. The polishing head 10 is configured so that it can hold the substrate W on its lower surface. The substrate W is held so that the surface to be polished faces downward.

[0025] The head shaft 11 is rotatably supported at the free end of a head swing arm 16. A head swing mechanism (not shown) equipped with an electric motor and the like is disposed inside the head swing arm 16. The head swing mechanism is connected to the head swing shaft 14. The head swing mechanism is configured to swing the polishing head 10 together with the head shaft 11 about the axis of the head swing shaft 14 via the head swing arm 16.

[0026] Furthermore, a head rotation mechanism 18 equipped with an electric motor or the like is disposed within the head swing arm 16. This head rotation mechanism 18 is connected to the head shaft 11 and configured to rotate the polishing head 10 together with the head shaft 11 about the axis of the head shaft 11. The head rotation mechanism 18 is configured, for example, by a combination of a motor, a timing pulley, and a belt. In FIG. 1, the head rotation mechanism 18 is illustrated diagrammatically.

[0027] The head shaft 11 is connected to a head lifting mechanism (not shown). This head lifting mechanism is configured to move the head shaft 11 up and down relative to the head swing arm 16. The head lifting mechanism is configured, for example, by a combination of a ball screw and a servo motor. By the up and down movement of the head shaft 11, the polishing head 10 can move up and down relative to the head swing arm 16 and the polishing table 3.

[0028] The polishing apparatus further includes an operation control unit 9. The polishing head system 1, the polishing liquid supply nozzle 5, the table motor 6, and the film thickness sensor 7 are electrically connected to the operation control unit 9, and the operations of the polishing head system 1, the polishing liquid supply nozzle 5, the table motor 6, and the film thickness sensor 7 are controlled by the operation control unit 9. In one embodiment, the polishing head system 1 may include the operation control unit 9.

[0029] The operation control unit 9 is composed of at least one computer. The operation control unit 9 includes a storage device 9a in which a program for controlling the operation of the polishing apparatus is stored, and a processing device 9b that executes calculations according to instructions included in the program. The storage device 9a includes a main storage device such as a random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) and a solid state drive (SSD). Examples of the processing device 9b include a CPU (central processing unit) and a GPU (graphic processing unit). However, the specific configuration of the operation control unit 9 is not limited to these examples.

[0030] The substrate W is polished as follows. While the polishing table 3 and polishing head 10 are rotated in the directions indicated by the arrows in Fig. 1, a polishing liquid is supplied from a polishing liquid supply nozzle 5 to the polishing surface 2a of the polishing pad 2 on the polishing table 3. While being rotated by the polishing head 10, the substrate W is pressed against the polishing surface 2a of the polishing pad 2 by the polishing head 10 with the polishing liquid present on the polishing pad 2. The surface of the substrate W is polished by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad 2.

[0031] During polishing of the substrate W, the film thickness sensor 7 rotates together with the polishing table 3 and acquires a film thickness signal while moving across the surface of the substrate W. This film thickness signal is an index value that directly or indirectly indicates the film thickness, and changes as the film thickness of the substrate W decreases. The film thickness sensor 7 is connected to an operation controller 9, and the film thickness signal is sent to the operation controller 9. The operation controller 9 terminates polishing of the substrate W when the film thickness of the substrate W, which is indicated by the film thickness signal, reaches a predetermined target value.

[0032] Next, the details of the configuration of the polishing head system 1 will be described. Fig. 2 is a cross-sectional view that shows a schematic diagram of one embodiment of the polishing head system 1. In Fig. 2, the head swing shaft 14, the head swing arm 16, and the head rotation mechanism 18 are omitted. As shown in Fig. 2, the polishing head 10 includes a carrier 31 fixed to the end of the head shaft 11, an elastic membrane 34 attached to the lower part of the carrier 31, a retainer ring 40 arranged to surround the substrate W and the elastic membrane 34, and a drive ring 42 fixed to the upper surface of the retainer ring 40.

[0033] The elastic membrane 34 has a substrate pressing surface 35 for pressing the substrate W against the polishing surface 2a of the polishing pad 2, and four annular partition walls 36A, 36B, 36C, and 36D extending upward from the substrate pressing surface 35. The substrate pressing surface 35 has substantially the same size and shape as the upper surface of the substrate W. The partition walls 36A to 36D are endless walls arranged concentrically. The partition walls 36A to 36D form four pressure chambers Ca1, Ca2, Ca3, and Ca4 between the elastic membrane 34 and the carrier 31. The elastic membrane 34 is made of an elastic material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicone rubber.

[0034] In this embodiment, the elastic membrane 34 forms four pressure chambers Ca1 to Ca4, but the present invention is not limited to this embodiment. In one embodiment, the elastic membrane 34 may form fewer than four or more than four pressure chambers. That is, in one embodiment, the elastic membrane 34 may have fewer than four partition walls or more than four partition walls. For example, the elastic membrane 34 may have only one partition wall and form only one pressure chamber.

[0035] The carrier 31, the retainer ring 40, and the drive ring 42 are made of resin such as engineering plastic (e.g., PEEK). The carrier 31 may be made of metal such as SUS or aluminum. The retainer ring 40 is disposed so as to surround the substrate W and the substrate pressing surface 35 of the elastic film 34. The retainer ring 40 is an annular structure that holds the substrate W to prevent the substrate W from jumping out of the polishing head 10 during polishing.

[0036] The drive ring 42 is an annular structure disposed below the carrier 31. The polishing head 10 further includes a plurality of retainer ring pressing membranes 45A-45F between the carrier 31 and the drive ring 42. The drive ring 42 is connected to the plurality of retainer ring pressing membranes 45A-45F. The drive ring 42 is located between the retainer ring 40 and the plurality of retainer ring pressing membranes 45A-45F.

[0037] Fig. 3 is a top view showing one embodiment of partition walls 36A-36D and retainer ring pressing membranes 45A-45F. As shown in Fig. 3, in this embodiment, six retainer ring pressing membranes 45A, 45B, 45C, 45D, 45E, and 45F are arranged along the circumferential direction of retainer ring 40. When viewed from above, retainer ring pressing membranes 45A-45F have a substantially fan-shaped or arc-shaped configuration. As shown in Fig. 2, the cross section of retainer ring pressing membranes 45A-45F is rectangular.

[0038] Pressure chambers Cb1, Cb2, Cb3, Cb4, Cb5, and Cb6 are formed inside the retainer ring pressing films 45A, 45B, 45C, 45D, 45E, and 45F, respectively. The pressure chambers Cb1 to Cb6 are arranged along the circumferential direction of the retainer ring 40. The retainer ring pressing films 45A to 45F are formed of elastic materials having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicone rubber. In this embodiment, the polishing head 10 has six retainer ring pressing films 45A to 45F and six pressure chambers Cb1 to Cb6, but the number of retainer ring pressing films and pressure chambers is not limited to this embodiment. In one embodiment, the polishing head 10 may have fewer than six or more than six retainer ring pressing films, and may have fewer than six or more than six pressure chambers.

[0039] 2, the rotary joint assembly 20 includes four rotary joints 21A, 21B, 21C, and 21D and a multi-path rotary joint 25. The rotary joints 21A to 21D and the multi-path rotary joint 25 are arranged along the axial direction of the head shaft 11. The pressure chambers Ca1, Ca2, Ca3, and Ca4 formed by the elastic film 34 are connected to fluid transfer lines Fa1, Fa2, Fa3, and Fa4, respectively. The fluid transfer lines Fa1 to Fa4 extend through the carrier 31, the head shaft 11, and the rotary joints 21A to 21D, respectively.

[0040] The polishing head system 1 further includes fluid supply lines La1, La2, La3, and La4 connected to the rotary joints 21A to 21D, respectively, and pressure regulators Ra1, Ra2, Ra3, and Ra4 attached to the fluid supply lines La1, La2, La3, and La4, respectively. The fluid transfer lines Fa1, Fa2, Fa3, and Fa4 are connected to the fluid supply lines La1, La2, La3, and La4, respectively. One end of the fluid supply lines La1 to La4 is connected to a compressed fluid supply source (not shown) as a utility supply source provided in a factory where the polishing apparatus is installed.

[0041] Compressed fluid (e.g., compressed gas such as compressed air) from a compressed fluid supply source is supplied independently into the pressure chambers Ca1-Ca4 through fluid supply lines La1-La4 and fluid transfer lines Fa1-Fa4. The pressure regulators Ra1-Ra4 are configured to independently adjust the pressure of the compressed fluid in the pressure chambers Ca1-Ca4. The compressed fluid in the pressure chambers Ca1-Ca4 generates a pressing force for pressing the substrate W against the polishing surface 2a of the polishing pad 2. The pressure regulators Ra1-Ra4 can independently adjust the pressing force applied to the polishing pad 2 in four regions of the substrate W corresponding to the positions of the pressure chambers Ca1-Ca4.

[0042] The fluid supply lines La1-La4 may each be connected to an atmosphere release valve (not shown). In this case, the pressure chambers Ca1-Ca4 can be opened to the atmosphere by operating the atmosphere release valve. The pressure regulators Ra1-Ra4 and the atmosphere release valves are connected to an operation control unit 9. The operation control unit 9 sends target pressure values ​​for the pressure chambers Ca1-Ca4 to the pressure regulators Ra1-Ra4, and operates the pressure regulators Ra1-Ra4 so that the pressures in the pressure chambers Ca1-Ca4 become the corresponding target pressure values.

[0043] The pressure chambers Cb1, Cb2, Cb3, Cb4, Cb5, and Cb6 formed by the retainer ring pressing films 45A to 45F are connected to fluid transfer lines Fb1, Fb2, Fb3, Fb4, Fb5, and Fb6 (see FIG. 3), respectively. The fluid transfer lines Fb1 to Fb6 extend through the carrier 31, the head shaft 11, and the multi-path rotary joint 25.

[0044] 4 is a top view showing the multi-path rotary joint 25. The polishing head system 1 further includes fluid supply lines Lb1, Lb2, Lb3, Lb4, Lb5, and Lb6 connected to the multi-path rotary joint 25, and pressure regulators Rb1, Rb2, Rb3, Rb4, Rb5, and Rb6 attached to the fluid supply lines Lb1, Lb2, Lb3, Lb4, Lb5, and Lb6, respectively. The fluid transfer lines Fb1, Fb2, Fb3, Fb4, Fb5, and Fb6 are connected to the fluid supply lines Lb1, Lb2, Lb3, Lb4, Lb5, and Lb6, respectively. One end of the fluid supply lines Lb1 to Lb6 is connected to a compressed fluid supply source (not shown) as a utility supply source provided in a factory where the polishing apparatus is installed. In this embodiment, the polishing head system 1 has six fluid supply lines Lb1 to Lb6, but the number of fluid supply lines is not limited to this embodiment. In one embodiment, the polishing head system 1 may have fewer than six fluid supply lines or more than six fluid supply lines.

[0045] The multi-path rotary joint 25, the details of which will be described later, is configured to switch communication between the fluid supply lines Lb1-Lb6 and the fluid transfer lines Fb1-Fb6 one by one in accordance with the rotation of the head shaft 11. Compressed fluid (e.g., compressed gas such as compressed air) from a compressed fluid supply source is independently supplied to the pressure chambers Cb1-Cb6 through the fluid supply lines Lb1-Lb6 and the fluid transfer lines Fb1-Fb6. The pressure regulators Rb1-Rb6 are configured to independently adjust the pressure of the compressed fluid in the fluid supply lines Lb1-Lb6.

[0046] The pressures in the pressure chambers Cb1-Cb6 are adjusted to the set pressure values ​​of the pressure regulators Rb1-Rb6 attached to the corresponding fluid supply lines Lb1-Lb6. When the head shaft 11 rotates and the fluid supply lines Lb1-Lb6 communicating with the pressure chambers Cb1-Cb6 are switched, the pressures in the pressure chambers Cb1-Cb6 are switched to the set pressure values ​​of the corresponding pressure regulators Rb1-Rb6. The pressure chambers Cb1-Cb6 generate pressing forces for pressing six regions of the retaining ring 40 corresponding to the positions of the pressure chambers Cb1-Cb6 against the polishing surface 2a of the polishing pad 2. The pressing forces generated by the pressure chambers Cb1-Cb6 are applied to the retaining ring 40 via the drive ring 42.

[0047] The fluid supply lines Lb1-Lb6 may each be connected to an air release valve (not shown). In this case, by operating the air release valve, the fluid supply lines Lb1-Lb6 and the pressure chambers Cb1-Cb6 communicating with them can be opened to the atmosphere. The pressure regulators Rb1-Rb6 and the air release valves are connected to an operation control unit 9. The operation control unit 9 sends set pressure values ​​of the compressed fluid in the fluid supply lines Lb1-Lb6 to the pressure regulators Rb1-Rb6, and operates the pressure regulators Rb1-Rb6 so that the pressure of the compressed fluid in the fluid supply lines Lb1-Lb6, i.e., the pressure in the pressure chambers Cb1-Cb6 communicating with the fluid supply lines Lb1-Lb6, becomes the set pressure value.

[0048] The fluid transfer lines Fa1-Fa4 and the fluid transfer lines Fb1-Fb6 are disposed at different positions in the circumferential direction of the head shaft 11. The positional relationship between the fluid transfer lines Fa1-Fa4 and the fluid transfer lines Fb1-Fb6 is not limited to this embodiment as long as they do not overlap each other.

[0049] Next, the configuration of rotary joints 21A to 21D will be described. Fig. 5 is a cross-sectional view of rotary joint assembly 20 shown in Fig. 3 taken along line AA. Fig. 6 is a cross-sectional view of rotary joint assembly 20 taken along line BB in Fig. 5. Rotary joints 21A to 21D are disposed so as to surround at least a portion of head shaft 11, and are disposed along the axial direction of head shaft 11. Since rotary joints 21A to 21D have basically the same configuration, the configuration of rotary joint 21A will be described below. The arrangement of rotary joints 21A to 21D in the axial direction of head shaft 11 is not limited to this embodiment.

[0050] The fluid transfer line Fa1 is composed of a flow path including a shaft flow path 51 formed in the head shaft 11 and a joint flow path 54 formed in the rotary joint 21A. The shaft flow path 51 has a shaft opening 51a that opens to the outer surface 11a of the head shaft 11. The shaft flow path 51 further has a bent portion 51b. The shaft flow path 51 extends upward from the lower end of the head shaft 11 along the axial direction of the head shaft 11, bends at the bent portion 51b, and extends to the shaft opening 51a. The shaft flow path 51 communicates with the pressure chamber Ca1.

[0051] The rotary joint 21A has a ring passage 54a, which is an annular groove formed in the inner surface 22a along the circumferential direction, and a connection port 54b that opens at the outer surface 22b of the rotary joint 21A. The joint passage 54 communicates with the ring passage 54a and the connection port 54b. The shaft opening 51a faces the ring passage 54a. The shaft passage 51 and the joint passage 54 communicate with each other through the ring passage 54a. The fluid supply line La1 is connected to the rotary joint 21A at the connection port 54b and communicates with the joint passage 54.

[0052] When the head shaft 11 rotates, the rotary joint 21A and the fluid supply line La1 do not rotate, and their positions are fixed (i.e., remain stationary). When the head shaft 11 rotates together with the polishing head 10, the shaft opening 51a moves in the circumferential direction along the ring flow passage 54a, so that the fluid supply line La1 and the fluid transfer line Fa1 are always in communication. Therefore, while the head shaft 11 is rotating, the compressed fluid is continuously supplied to the pressure chamber Ca1 through the fluid supply line La1 and the fluid transfer line Fa1.

[0053] Next, the configuration of the multi-path rotary joint 25 will be described. FIG. 7 is an exploded view showing one embodiment of the multi-path rotary joint 25. FIG. 8 is an enlarged cross-sectional view of the multi-path rotary joint 25 shown in FIG. 7. FIG. 9 is a cross-sectional view taken along the line CC in FIG. 8. The multi-path rotary joint 25 is disposed so as to surround at least a part of the head shaft 11. The multi-path rotary joint 25 has a plurality of (six in this embodiment) joint members 60 disposed along the circumferential direction of the head shaft 11, and a joint holder 62 disposed so as to surround these joint members 60. The number of the joint members 60 corresponds to the number of the fluid supply lines Lb1 to Lb6 connected to the multi-path rotary joint 25. The joint member 60 is a plate structure having a circular arc shape when viewed from above, and has a shape obtained by dividing an annular structure into six equal parts. The joint holder 62 is an annular structure.

[0054] The multi-path rotary joint 25 of this embodiment has six connection ports 58b for connecting to six fluid supply lines Lb1 to Lb6. The fluid transfer lines Fb1 to Fb6 are each composed of a flow path including six shaft flow paths 56 formed in the head shaft 11 and six joint flow paths 58 formed in the multi-path rotary joint 25. The six shaft flow paths 56 each have six shaft openings 56a that open on the outer surface 11a of the head shaft 11. Each shaft flow path 56 further has a bent portion 56b. The shaft flow path 56 extends upward from the lower end of the head shaft 11 along the axial direction of the head shaft 11, bends at the bent portion 56b, and extends to the shaft opening 56a. The multiple shaft flow paths 56 are each connected to the pressure chambers Cb1 to Cb6.

[0055] The six joint flow passages 58 have six joint openings 58a that open on the inner surface 25a of the multi-path rotary joint 25 and six connection ports 58b that open on the outer surface 25b of the multi-path rotary joint 25. The joint openings 58a face the shaft openings 56a. The six shaft openings 56a and the six joint openings 58a are arranged along the circumferential direction of the head shaft 11 and are at the same position in the axial direction of the head shaft 11. The shaft flow passages 56 and the joint flow passages 58 communicate with each other through the shaft openings 56a and the joint openings 58a. The fluid supply lines Lb1 to Lb6 are connected to the multi-path rotary joint 25 through the six connection ports 58b and communicate with the six joint flow passages 58, respectively.

[0056] The multi-path rotary joint 25 is configured to sequentially connect each of the fluid supply lines Lb1 to Lb6 to the six shaft flow paths 56 each time the head shaft 11 rotates once together with the polishing head 10. When the head shaft 11 is rotating, the multi-path rotary joint 25 and the fluid supply lines Lb1 to Lb6 do not rotate, and their positions are fixed (i.e., they remain stationary).

[0057] When the head shaft 11 rotates, the six shaft openings 56a move in the circumferential direction of the head shaft 11, so that each shaft opening 56a alternately faces the joint opening 58a and the inner surface 25a of the multi-path rotary joint 25. When the shaft opening 56a faces the joint opening 58a, each shaft flow passage 56 communicates with the corresponding joint flow passage 58. Therefore, during the rotation of the head shaft 11, the compressed fluid in the fluid supply lines Lb1 to Lb6 is sequentially supplied to the pressure chambers Cb1 to Cb6 by switching the fluid transfer lines Fb1 to Fb6 that communicate with the fluid supply lines Lb1 to Lb6, respectively. That is, every time the head shaft 11 rotates once, the compressed fluid is supplied once to each of the pressure chambers Cb1 to Cb6 from all the fluid supply lines Lb1 to Lb6.

[0058] Six joint flow paths 58 extend through the six joint members 60 and the joint holder 62. The six joint openings 58a open on the inner surfaces of the six joint members 60, respectively. The six connection ports 58b open on the outer surface of the joint holder 62. As shown in FIG. 9, each joint opening 58a extends in the circumferential direction of the head shaft 11, and the width of each joint opening 58a is greater than the width of each shaft opening 56a. This ensures that each shaft flow path 56 communicates with the joint flow path 58 for a sufficient period of time when the head shaft 11 rotates and the joint openings 58a facing each shaft opening 56a are switched in sequence. As a result, the compressed fluid can be supplied sufficiently to the pressure chambers Cb1 to Cb6.

[0059] There may be slight gaps between the six joint members 60 and the joint holder 62. As shown in Fig. 7, each joint member 60 has a plurality of spring retaining holes 60a. The spring retaining holes 60a are formed in the outer surface of the joint member 60 and extend radially inward of the multi-path rotary joint 25. The spring retaining holes 60a do not penetrate the joint member 60.

[0060] The multi-path rotary joint 25 has a spring 65 disposed in each spring holding hole 60a. The springs 65 are configured to press each of the six joint members 60 against the head shaft 11 by their elastic force. This allows the six joint members 60 and the head shaft 11 to be in close contact with each other, minimizing leakage of compressed fluid at the connection point between the shaft flow passage 56 and the joint flow passage 58. The multiple joint members 60 and the head shaft 11 are formed of a hard material (for example, ceramics such as SiC, carbon, or metals such as SUS and aluminum).

[0061] The number of the joint members 60 is arbitrary as long as the joint members 60 and the head shaft 11 can be brought into close contact with each other, and may be less than six or more than six. For example, one joint member 60 may be provided for two joint flow paths 58. In this embodiment, four spring holding holes 60a and four springs 65 are provided for each joint member 60, but the number of the spring holding holes 60a and the springs 65 is arbitrary as long as the joint members 60 and the head shaft 11 can be brought into close contact with each other, and may be less than four or more than four. In one example, one spring holding hole 60a and one spring 65 may be provided for each joint member 60.

[0062] The multipath rotary joint 25 has a plurality of positioning mechanisms 68 (six in this embodiment) that fix the relative positions of the six joint members 60 with respect to the joint holder 62 in the circumferential direction. FIG. 10 is an enlarged cross-sectional view showing one embodiment of the positioning mechanism 68. The positioning mechanism 68 includes a protrusion 60b formed on the outer surface of each joint member 60 and a recess 62a formed on the inner surface of the joint holder 62. The joint flow passage 58 extends through the protrusion 60b. The positioning mechanism 68 is configured to restrict the movement of the joint members 60 in the circumferential direction with respect to the joint holder 62 by fitting the protrusion 60b of the joint member 60 into the recess 62a of the joint holder 62. On the other hand, the positioning mechanism 68 is configured to allow the movement of the joint members 60 in the radial direction with respect to the joint holder 62.

[0063] The six positioning mechanisms 68 each have six seal mechanisms 70 that seal the gap between the outer surface of the protrusion 60b of the joint member 60 and the inner surface of the recess 62a of the joint holder 62. Each seal mechanism 70 is composed of a seal groove 62b formed in the joint holder 62 and an endless seal member (e.g., an O-ring) 72. The seal groove 62b is formed on the surface that constitutes the recess 62a. The endless seal member 72 is disposed in the seal groove 62b. When the joint member 60 moves radially relative to the joint holder 62, the seal mechanism 70 seals the gap between the outer surface of the protrusion 60b and the inner surface of the recess 62a, thereby preventing the compressed fluid from leaking from the joint flow path 58.

[0064] The configuration of the positioning mechanism 68 is not limited to this embodiment as long as it can fix the relative positions of the six joint members 60 with respect to the joint holder 62 in the circumferential direction. In one embodiment, the positioning mechanism 68 may have a recess formed in the joint member 60 and a protrusion formed in the joint holder 62. The configuration of the sealing mechanism 70 is not limited to this embodiment as long as it can seal the gap between the joint member 60 and the joint holder 62. In one embodiment, the sealing mechanism 70 may be composed of a seal groove and an endless seal member formed in the joint member 60.

[0065] FIG. 11 is a diagram showing a plurality of pressure regions PR1 to PR6 indicating positions at which the pressing forces generated by the plurality of pressure chambers Cb1 to Cb6 on the plurality of regions of the retaining ring 40 are switched. The pressure chambers Cb1 to Cb6 of the polishing head 10 also rotate with the rotation of the head shaft 11. Each of the pressure chambers Cb1 to Cb6 is sequentially connected to the fluid supply lines Lb1 to Lb6 by the multi-path rotary joint 25 with the rotation of the head shaft 11. The plurality of pressure regions PR1 to PR6 correspond to the positions of the fluid supply lines Lb1 to Lb6, and the relative positions of the plurality of pressure regions PR1 to PR6 with respect to the polishing pad 2 are fixed. That is, while the pressure chambers Cb1 to Cb6 of the polishing head 10 rotate, the plurality of pressure regions PR1 to PR6 do not rotate. Each of the plurality of pressure regions PR1 to PR6 has an arc shape when viewed from above.

[0066] The pressure chambers located in the pressure region PR1 shown in FIG. 11 communicate with the fluid supply line Lb1, the pressure chambers located in the pressure region PR2 communicate with the fluid supply line Lb2, the pressure chambers located in the pressure region PR3 communicate with the fluid supply line Lb3, the pressure chambers located in the pressure region PR4 communicate with the fluid supply line Lb4, the pressure chambers located in the pressure region PR5 communicate with the fluid supply line Lb5, and the pressure chambers located in the pressure region PR6 communicate with the fluid supply line Lb6. As the polishing head 10 and the head shaft 11 rotate, the fluid supply lines communicating with the pressure chambers located in each of the pressure regions PR1 to PR6 are sequentially switched. The relative positions of the plurality of pressure regions PR1 to PR6 with respect to the polishing pad 2 may be adjusted by the pressure of the compressed fluid supplied from the fluid supply lines Lb1 to Lb6, the rotation speed of the polishing pad 2, the rotation speed of the polishing head 10 (head shaft 11), and the like.

[0067] During the polishing of the substrate W, basically, the pressure regulators Rb1 to Rb6 operate to maintain the set pressure value of the compressed fluid in the fluid supply lines Lb1 to Lb6 constant. FIG. 12 is a graph showing an embodiment of the transition of the pressure in the pressure chamber Cb1 that changes as the polishing head 10 (head shaft 11) rotates. In FIG. 12, the horizontal axis represents the rotation angle of the pressure chamber Cb1, and the vertical axis represents the pressure in the pressure chamber Cb1. In this embodiment, the set pressure value of the compressed fluid in the fluid supply line Lb1 (i.e., the set pressure value in the pressure region PR1) is P2, the set pressure value of the compressed fluid in the fluid supply line Lb2 (i.e., the set pressure value in the pressure region PR2) is P3 (>P2), the set pressure value of the compressed fluid in the fluid supply line Lb3 (i.e., the set pressure value in the pressure region PR3) is P3, the set pressure value of the compressed fluid in the fluid supply line Lb4 (i.e., the set pressure value in the pressure region PR4) is P2, the set pressure value of the compressed fluid in the fluid supply line Lb5 (i.e., the set pressure value in the pressure region PR5) is P1 (<P2), and the set pressure value of the compressed fluid in the fluid supply line Lb6 (i.e., the set pressure value in the pressure region PR6) is P1.

[0068] 11 together with the rotation of the polishing head 10 and the head shaft 11. When the pressure chamber Cb1 is located in the pressure region PR1, the rotation angle of the pressure chamber Cb1 is 0 degrees, when the pressure chamber Cb1 is located in the pressure region PR2, the rotation angle of the pressure chamber Cb1 is 60 degrees, when the pressure chamber Cb1 is located in the pressure region PR3, the rotation angle of the pressure chamber Cb1 is 120 degrees, when the pressure chamber Cb1 is located in the pressure region PR4, the rotation angle of the pressure chamber Cb1 is 180 degrees, when the pressure chamber Cb1 is located in the pressure region PR5, the rotation angle of the pressure chamber Cb1 is 240 degrees, and when the pressure chamber Cb1 is located in the pressure region PR6, the rotation angle of the pressure chamber Cb1 is 300 degrees. Therefore, the pressure in the pressure chamber Cb1 is P2 when the pressure chamber Cb1 is located in pressure region PR1 (0 degrees), P3 when the pressure chamber Cb1 is located in pressure region PR2 (60 degrees), P3 when the pressure chamber Cb1 is located in pressure region PR3 (120 degrees), P2 when the pressure chamber Cb1 is located in pressure region PR4 (180 degrees), P1 when the pressure chamber Cb1 is located in pressure region PR5 (240 degrees), and P1 when the pressure chamber Cb1 is located in pressure region PR6 (300 degrees).

[0069] 12, the pressure in the pressure chamber Cb1 switches sequentially between the set pressure values ​​P1-P3 of the compressed fluid in the fluid supply lines Lb1-Lb6 each time the head shaft 11 (i.e., the pressure chamber Cb1) rotates once. When the set pressure values ​​of adjacent fluid supply lines are different, the pressure in the pressure chamber Cb1 switches gradually. When the set pressure values ​​of adjacent fluid supply lines are the same, the pressure in the pressure chamber Cb1 is maintained at that set pressure value.

[0070] Similarly to the pressure chamber Cb1, the pressures in the other pressure chambers Cb2 to Cb6 are sequentially switched to the set pressure values ​​P1 to P3 of the compressed fluid in the fluid supply lines Lb1 to Lb6 every time the head shaft 11 (i.e., the pressure chambers Cb2 to Cb6) rotate once. In this way, the six regions of the retaining ring 40 corresponding to the positions of the pressure chambers Cb1 to Cb6 can be pressed against the polishing surface 2a of the polishing pad 2 with a plurality of pressing forces according to the pressures in the pressure chambers Cb1 to Cb6. As a result, the polishing rate at the edge portion of the substrate W can be precisely controlled. The plurality of pressing forces applied to the six regions of the retaining ring 40 include at least two different pressing forces. One of the at least two different pressing forces may be unpressurized (i.e., the pressing force is 0) when the fluid supply lines Lb1 to Lb6 are opened to the atmosphere by an atmosphere release valve attached to the fluid supply lines Lb1 to Lb6.

[0071] According to this embodiment, by using the multi-path rotary joint 25, the polishing rate at the edge portion of the substrate W can be precisely controlled.

[0072] In this embodiment, the pressures in the pressure chambers Cb1 to Cb6 are adjusted by the pressure regulators Rb1 to Rb6, respectively, so that the pressing force generated by the pressure chambers located in the pressure regions PR2 and PR3 is greater than the pressing force generated by the other pressure chambers. During polishing of the substrate W, the retaining ring 40 receives a frictional force between the substrate W and the retaining ring 40, and the retaining ring 40 is in a floating state on the downstream side in the rotation direction of the polishing pad 2 (polishing surface 2a), i.e., in the region corresponding to the vicinity of the pressure regions PR2 and PR3 in FIG. 11. Conversely, the retaining ring 40 is in a sunk state into the polishing pad 2 on the upstream side, i.e., in the region corresponding to the vicinity of the pressure regions PR5 and PR6 in FIG. 11. Therefore, by making the pressing force generated by the pressure chambers located downstream in the rotation direction of the polishing pad 2 (polishing surface 2a), i.e., in the pressure regions PR2 and PR3, greater than the pressing force generated by the other pressure chambers, a large pressing force is applied to the downstream portion of the retaining ring 40. This makes it possible to effectively control the polishing rate at the edge portion of the substrate W.

[0073] During polishing of the substrate W, the substrate W is pressed against the inner peripheral surface of the retainer ring 40 by friction with the polishing surface 2a, so that the gap between the retainer ring 40 and the substrate W is smallest on the downstream side in the rotation direction of the polishing pad 2 (polishing surface 2a). Therefore, by making the pressing force generated by the pressure chambers located on the downstream side in the rotation direction of the polishing pad 2 (polishing surface 2a), i.e., in the pressure regions PR2 and PR3, greater than the pressing forces generated by the other pressure chambers, the influence of pad rebound can be made noticeable on the substrate W.

[0074] 13 is a graph showing another embodiment of the transition of the pressure in the pressure chamber Cb1 that changes with the rotation of the polishing head 10 (head shaft 11). The configuration and operation of this embodiment that are not particularly described are similar to those of the embodiment described with reference to FIG. 12, so the overlapping description will be omitted. In this embodiment, the set pressure value of the compressed fluid in the fluid supply line Lb1 (i.e., the set pressure value in the pressure region PR1) is 0, the set pressure value of the compressed fluid in the fluid supply line Lb2 (i.e., the set pressure value in the pressure region PR2) is P4, the set pressure value of the compressed fluid in the fluid supply line Lb3 (i.e., the set pressure value in the pressure region PR3) is P4, the set pressure value of the compressed fluid in the fluid supply line Lb4 (i.e., the set pressure value in the pressure region PR4) is 0, the set pressure value of the compressed fluid in the fluid supply line Lb5 (i.e., the set pressure value in the pressure region PR5) is 0, and the set pressure value of the compressed fluid in the fluid supply line Lb6 (i.e., the set pressure value in the pressure region PR6) is 0.

[0075] The pressure in the pressure chamber Cb1 is 0 when the pressure chamber Cb1 is located in the pressure region PR1 (0 degrees), P4 when the pressure chamber Cb1 is located in the pressure region PR2 (60 degrees), P4 when the pressure chamber Cb1 is located in the pressure region PR3 (120 degrees), 0 when the pressure chamber Cb1 is located in the pressure region PR4 (180 degrees), 0 when the pressure chamber Cb1 is located in the pressure region PR5 (240 degrees), and 0 when the pressure chamber Cb1 is located in the pressure region PR6 (300 degrees). As shown in FIG. 13, the pressure in the pressure chamber Cb1 is sequentially switched to the set pressure values ​​0 and P4 of the compressed fluid in the fluid supply lines Lb1 to Lb6 every time the head shaft 11 (i.e., the pressure chamber Cb1) rotates once. In this embodiment, when the pressure chamber is located in the pressure regions PR2 and PR3, a pressing force against the retaining ring 40 is generated, and when the pressure chamber is located in the other pressure regions, no pressing force against the retaining ring 40 is generated. 12, a larger difference in pressing force occurs between the downstream side and the upstream side of the retainer ring 40 in the rotation direction of the polishing pad 2 (polishing surface 2a).

[0076] 12 and 13, as an example, the set pressure values ​​of the compressed fluid in the fluid supply lines Lb2 and Lb3 (i.e., the set pressure values ​​in the pressure regions PR2 and PR3) are set to be greater than the set pressure values ​​of the compressed fluid in the other fluid supply lines so that a large pressing force is applied to the portion downstream of the retaining ring 40 in the rotation direction of the polishing pad 2 (polishing surface 2a), but the set pressure values ​​of the compressed fluid in the fluid supply lines Lb1 to Lb6 are not limited to these examples. In one embodiment, the set pressure values ​​of the compressed fluid in the fluid supply lines Lb5 and Lb6 (i.e., the set pressure values ​​in the pressure regions PR5 and PR6) may be set to be greater than the set pressure values ​​of the compressed fluid in the other fluid supply lines so that a large pressing force is applied to the portion upstream of the retaining ring 40 in the rotation direction of the polishing pad 2 (polishing surface 2a).

[0077] In another embodiment, only the pressure regulator Rb3 among the pressure regulators Rb1 to Rb6 may be operated to maintain the set pressure value of the compressed fluid in the fluid supply line Lb3 constant, and the air release valves connected to the fluid supply lines Lb1, Lb2, Lb4 to Rb6 may be operated to open the fluid supply lines Lb1, Lb2, Lb4 to Rb6 to the atmosphere. In this case, a pressing force is applied only to the region of the retaining ring 40 corresponding to the pressure region PR3, and no pressing force is applied to other regions of the retaining ring 40. In this way, when applying a pressing force only to the region of the retaining ring 40 corresponding to a specific pressure region, a pressure regulator may be attached to only a specific fluid supply line among the multiple fluid supply lines, and only air release valves may be attached to the other fluid supply lines.

[0078] FIG. 14 is an exploded view showing another embodiment of the multi-path rotary joint 25. FIG. 15 is a cross-sectional view of the multi-path rotary joint 25 shown in FIG. 14. In this embodiment, as shown in FIG. 14 and FIG. 15, the multi-path rotary joint 25 includes one joint member 60 and a joint holder 62, and the joint holder 62 has only one connection port 58b. The polishing head system 1 includes one fluid supply line Lb1 and one pressure regulator Rb1 attached to the fluid supply line Lb1. The fluid supply line Lb1 is connected to the multi-path rotary joint 25 at the connection port 58b.

[0079] The multi-path rotary joint 25 may include a spacer 63 located on the opposite side of the head shaft 11 from the joint member 60. The spacer 63 is disposed between the joint holder 62 and the head shaft 11. The joint member 60 and the spacer 63 are symmetrical with respect to the head shaft 11. As shown in FIG. 15, the spacer 63 has a protrusion 63a that fits into a recess 62c formed in the joint holder 62, and a through hole 63b that faces the shaft opening 56a. The protrusion 63a fits into the recess 62c of the joint holder 62, thereby fixing the circumferential position of the spacer 63 with respect to the joint holder 62.

[0080] The spacer 63 has spring retaining holes (not shown). The spring retaining holes are formed on the outer surface of the spacer 63 and extend radially inward of the multi-path rotary joint 25. The spring retaining holes do not penetrate the spacer 63. The multi-path rotary joint 25 has springs (not shown) disposed in each spring retaining hole. The springs are configured to press the spacer 63 against the head shaft 11 by their elastic force. This makes it possible to bring the spacer 63 and the head shaft 11 into close contact with each other and stabilize the relative position of the head shaft 11 and the joint holder 62. As a result, the spacer 63 can stabilize the radial position of the joint member 60 with respect to the joint holder 62.

[0081] During rotation of the head shaft 11, each shaft passage 56 communicates with the joint passage 58 only when the shaft opening 56a faces one of the joint openings 58a, and is open to the atmosphere when the shaft opening 56a does not face one of the joint openings 58a. Each shaft passage 56 is also open to the atmosphere when the shaft opening 56a faces the through hole 63b of the spacer 63. Therefore, when the pressure regulator Rb1 maintains the set pressure value of the compressed fluid in the fluid supply line Lb1 constant, a pressing force is applied only to the area of ​​the retaining ring 40 corresponding to the specific pressure area. The multiple pressing forces on the six areas of the retaining ring 40 include at least two different pressing forces. One of the at least two different pressing forces may be unpressurized (i.e., the pressing force is 0) by opening the shaft passage 56 to the atmosphere. Although the multi-path rotary joint 25 of this embodiment has only one connecting port 58b, it can substantially apply two different pressing forces to the six areas of the retaining ring 40.

[0082] In one embodiment, the spacer 63 may be omitted. Even in this case, during rotation of the head shaft 11, each shaft passage 56 communicates with the joint passage 58 only when it faces one of the joint openings 58a, and the other shaft passages 56 are open to the atmosphere.

[0083] Fig. 16 is a schematic diagram showing another embodiment of the polishing head 10. The configuration and operation of this embodiment that are not particularly described are similar to those of the above-mentioned embodiment, so duplicated descriptions will be omitted. Fig. 16 is a top view of the polishing head 10. The polishing head 10 of this embodiment has a plurality of rolling diaphragms 75A-75F instead of the plurality of retainer ring pressure membranes 45A-45F. These rolling diaphragms 75A-75F form a plurality of pressure chambers inside them.

[0084] In this embodiment, the multiple pressure chambers formed by the rolling diaphragms 75A to 75F are divided into multiple pressure chamber groups Cg1 to Cg6. That is, the pressure chamber group Cg1 includes five pressure chambers formed by five rolling diaphragms 75A, the pressure chamber group Cg2 includes five pressure chambers formed by five rolling diaphragms 75B, the pressure chamber group Cg3 includes five pressure chambers formed by five rolling diaphragms 75C, the pressure chamber group Cg4 includes five pressure chambers formed by five rolling diaphragms 75D, the pressure chamber group Cg5 includes five pressure chambers formed by five rolling diaphragms 75E, and the pressure chamber group Cg6 includes five pressure chambers formed by five rolling diaphragms 75F. The 30 rolling diaphragms 75A to 75F are arranged along the circumferential direction of the retainer ring 40. Each of the rolling diaphragms 75A to 75F has a cylindrical shape.

[0085] The rolling diaphragms 75A to 75F are formed of an elastic material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, silicone rubber, etc. In this embodiment, the polishing head 10 has 30 rolling diaphragms 75A to 75F, and each of the pressure chamber groups Cg1 to Cg6 is formed by five rolling diaphragms, but the present invention is not limited to this embodiment. In one embodiment, at least one pressure chamber belonging to one pressure chamber group may be formed by fewer than five or more than five rolling diaphragms.

[0086] FIG. 17 is a cross-sectional view of the rolling diaphragm 75A shown in FIG. 16. The rolling diaphragms 75A to 75F have basically the same configuration, so the configuration of the rolling diaphragm 75A will be described below. The rolling diaphragm 75A has a roll portion 76a and a pressing portion 76b. Each rolling diaphragm 75A forms a pressure chamber 78 inside. The drive ring 42 has a convex portion 42a that faces the pressing portion 76b of the rolling diaphragm 75A. The five rolling diaphragms 75A are connected to a fluid transfer line Fb1. More specifically, the fluid transfer line Fb1 is connected to the five rolling diaphragms 75A through a header 79 (see FIG. 16). The five rolling diaphragms 75A are connected to the header 79.

[0087] When compressed fluid is supplied to the pressure chambers 78 of the pressure chamber group Cg1 through the fluid transfer line Fb1, the pressing portions 76b of the five rolling diaphragms 75A are each pressed downward, exerting a pressing force on the convex portion 42a of the drive ring 42. This pressing force is imparted to the retaining ring 40 via the drive ring 42. In this way, the pressure chamber group Cg1 generates a pressing force for pressing the area of ​​the retaining ring 40 corresponding to the position of the pressure chamber group Cg1 against the polishing surface 2a of the polishing pad 2.

[0088] According to this embodiment, due to the structure of the rolling diaphragms 75A-75F having the roll portion 76a and the pressing portion 76b, the compressed fluid in the pressure chamber 78 formed by the rolling diaphragms 75A-75F efficiently acts as a force to expand the pressure chamber 78 downward, so that the intended pressing force can be generated. When the substrate is repeatedly polished, the retaining ring 40 wears due to friction with the polishing pad 2. The configuration using the rolling diaphragms 75A-75F can generate the intended pressing force, particularly even if the retaining ring 40 wears due to friction with the polishing pad 2.

[0089] FIG. 18 is a schematic diagram showing yet another embodiment of the polishing head 10. The configuration and operation of this embodiment not specifically described are similar to those of the embodiment described with reference to FIG. 16 and FIG. 17, and therefore the overlapping description will be omitted. FIG. 18 is a top view of the polishing head 10. The polishing head 10 of this embodiment further includes an annular pressure chamber Cc adjacent to the multiple pressure chamber groups Cg1 to Cg6. The polishing head 10 includes an annular rolling diaphragm 80 disposed inside the multiple rolling diaphragms 75A to 75F. The annular pressure chamber Cc is formed inside the annular rolling diaphragm 80.

[0090] FIG. 19 is a cross-sectional view of the rotary joint assembly 20 shown in FIG. 18 taken along the line DD. The rotary joint assembly 20 of this embodiment further includes a rotary joint 28. The annular pressure chamber Cc is connected to a fluid transfer line Fc. The fluid transfer line Fc extends through the carrier 31, the head shaft 11, and the rotary joint 28. The fluid transfer line Fc is configured by a flow path including a shaft flow path 81 formed in the head shaft 11 and a joint flow path 84 formed in the rotary joint 28. The polishing head system 1 includes a fluid supply line Lc connected to the rotary joint 28, and a pressure regulator Rc attached to the fluid supply line Lc. The fluid transfer line Fc is connected to the fluid supply line Lc. One end of the fluid supply line Lc is connected to a compressed fluid supply source (not shown) as a utility supply source provided in a factory in which the polishing apparatus is installed.

[0091] The configurations of the rotary joint 28, the shaft passage 81, and the joint passage 84 are the same as the configurations of the rotary joints 21A to 21D, the shaft passage 51, and the joint passage 54 described above, and therefore will not be described again.

[0092] A compressed fluid (e.g., compressed gas such as compressed air) from a compressed fluid supply source is supplied into the annular pressure chamber Cc through a fluid supply line Lc and a fluid transfer line Fc. The pressure regulator Rc is configured to adjust the pressure of the compressed fluid in the annular pressure chamber Cc. The annular pressure chamber Cc generates a uniform pressing force for pressing the entire retainer ring 40 against the polishing surface 2a of the polishing pad 2. This makes it possible to adjust the pressing force of the retainer ring 40 against the polishing pad 2.

[0093] The fluid supply lines Lc may each be connected to an atmosphere release valve (not shown). In this case, the annular pressure chamber Cc can be opened to the atmosphere by operating the atmosphere release valve. The pressure regulator Rc and the atmosphere release valve are connected to an operation control unit 9. The operation control unit 9 sends a target pressure value for the annular pressure chamber Cc to the pressure regulator Rc and operates the pressure regulator Rc so that the pressure in the annular pressure chamber Cc becomes the corresponding target pressure value.

[0094] FIG. 20 is a cross-sectional view of the rolling diaphragm 75A and the annular rolling diaphragm 80 shown in FIG. 18. The annular rolling diaphragm 80 includes a roll portion 80a and a pressing portion 80b. The drive ring 42 further includes a convex portion 42b that faces the pressing portion 80b of the annular rolling diaphragm 80. The annular rolling diaphragm 80 is connected to a fluid transfer line Fc. When compressed fluid is supplied from the fluid supply line Lc to the annular pressure chamber Cc, the pressing portion 80b of the annular rolling diaphragm 80 is pressed downward, exerting a pressing force on the convex portion 42b of the drive ring 42. This pressing force is applied to the retaining ring 40 via the drive ring 42. In this way, the annular pressure chamber Cc generates a pressing force for pressing the entire retaining ring 40 against the polishing surface 2a of the polishing pad 2 via the drive ring 42 located below the annular pressure chamber Cc.

[0095] According to this embodiment, the annular pressure chamber Cc applies the minimum necessary pressing force to the retaining ring 40 during polishing of the substrate W, while the multiple rolling diaphragms 75A-75F apply six pressing forces, including at least two different pressing forces, to six regions of the retaining ring 40 corresponding to the multiple pressure chamber groups Cg1-Cg6, respectively, thereby making it possible to precisely control the polishing rate at the edge portion of the substrate W.

[0096] In this embodiment, the annular rolling diaphragm 80 is disposed inside the multiple rolling diaphragms 75A to 75F, but in one embodiment, the annular rolling diaphragm 80 may be disposed outside the multiple rolling diaphragms 75A to 75F.

[0097] The annular rolling diaphragm 80 described with reference to Figures 18 to 20 can also be applied to the embodiment described with reference to Figures 1 to 13. That is, the annular rolling diaphragm 80 may be disposed inside or outside the above-mentioned plurality of retainer ring pressing membranes 45A-45F that form the plurality of pressure chambers Cb1-Cb6.

[0098] 12 and 13, the pressure in the pressure chambers Cb1-Cb6 of the polishing head 10 changes according to the set pressure value of the compressed fluid in the fluid supply lines Lb1-Lb6 as the polishing head 10 (head shaft 11) rotates. However, when the rotation speed of the polishing head 10 is high, the pressure in the pressure chambers Cb1-Cb6 of the polishing head 10 may not reach the set pressure value of the compressed fluid in the fluid supply lines Lb1-Lb6.

[0099] Fig. 21 is a graph for explaining the difference in pressure transition in one pressure chamber Cb1 depending on the rotation speed of the polishing head 10. In Fig. 21, the graph shown by the solid line represents the pressure transition in one pressure chamber Cb1 when the polishing head 10 is rotated at a relatively slow rotation speed E (e.g., 30 rpm). The graph shown by the dashed dotted line represents the pressure transition in one pressure chamber Cb1 when the polishing head 10 is rotated at a relatively fast rotation speed F (e.g., 90 rpm). Although Fig. 21 describes the pressure transition in the pressure chamber Cb1, the same applies to the pressure transitions in the other pressure chambers Cb2 to Cb6.

[0100] In the example shown in FIG. 21, the set pressure value of the compressed fluid in fluid supply line Lb1 (i.e., the set pressure value in pressure region PR1) is 0, the set pressure value of the compressed fluid in fluid supply line Lb2 (i.e., the set pressure value in pressure region PR2) is P5, the set pressure value of the compressed fluid in fluid supply line Lb3 (i.e., the set pressure value in pressure region PR3) is P5, the set pressure value of the compressed fluid in fluid supply line Lb4 (i.e., the set pressure value in pressure region PR4) is 0, the set pressure value of the compressed fluid in fluid supply line Lb5 (i.e., the set pressure value in pressure region PR5) is 0, and the set pressure value of the compressed fluid in fluid supply line Lb6 (i.e., the set pressure value in pressure region PR6) is 0.

[0101] When the polishing head 10 is rotated at a relatively slow rotation speed E, the pressure in the pressure chamber Cb1 is switched in sequence to the set pressure values ​​0 and P5 of the compressed fluid in the fluid supply lines Lb1 to Lb6 every time the polishing head 10 rotates once. More specifically, the pressure in the pressure chamber Cb1 is 0 when the pressure chamber Cb1 is located in the pressure region PR1 (0 degrees), P5 when the pressure chamber Cb1 is located in the pressure region PR2 (60 degrees), P5 when the pressure chamber Cb1 is located in the pressure region PR3 (120 degrees), 0 when the pressure chamber Cb1 is located in the pressure region PR4 (180 degrees), 0 when the pressure chamber Cb1 is located in the pressure region PR5 (240 degrees), and 0 when the pressure chamber Cb1 is located in the pressure region PR6 (300 degrees). The transition of the pressure in the other pressure chambers Cb2 to Cb6 is similar to the transition of the pressure in the pressure chamber Cb1.

[0102] In this specification, the pressure in the pressure chambers Cb1 to Cb6 that sequentially switches to the set pressure values ​​of the compressed fluid in the fluid supply lines Lb1 to Lb6 communicating with each of the pressure chambers Cb1 to Cb6 (e.g., 0, P5 as mentioned above) when the polishing head 10 is rotated at a relatively slow rotational speed E is defined as the "target pressure."

[0103] On the other hand, when the polishing head 10 is rotated at a relatively high rotation speed F, the time during which the pressure chamber Cb1 is located in each of the pressure regions PR1 to PR6 is shortened. That is, the time during which the pressure chamber Cb1 is in communication with each of the fluid supply lines Lb1 to Lb6 is shortened, and the time during which the pressure chamber Cb1 is in communication with the fluid supply lines Lb2 and Lb3, whose set pressure value of the compressed fluid is P5, is also shortened. Therefore, when the pressure chamber Cb1 is located between the pressure regions PR2 and PR3, the pressure in the pressure chamber Cb1 only rises to a pressure P5' that is smaller than the set pressure value P5 of the compressed fluid in the fluid supply line Lb1. The transition of the pressure in the other pressure chambers Cb2 to Cb6 is similar to the transition of the pressure in the pressure chamber Cb1.

[0104] In this way, when the rotation speed of the polishing head 10 is relatively high, the pressure in the pressure chambers Cb1-Cb6 may not reach the target pressure. As a result, the pressure chambers Cb1-Cb6 cannot apply a sufficient pressing force to the retaining ring 40. Therefore, in the embodiment described below, the operation control unit 9 is configured to send a corrected set pressure value that is higher than the set pressure value of the compressed fluid in the fluid supply lines Lb1-Lb6 to the pressure regulators Rb1-Rb6 when the pressure in the pressure chambers Cb1-Cb6 is lower than the target pressure, thereby correcting the pressure in the pressure chambers Cb1-Cb6.

[0105] FIG. 22 is a cross-sectional view showing a schematic diagram of another embodiment of the polishing head system 1. The configuration and operation of the present embodiment not specifically described are similar to those of the polishing head system 1 described with reference to FIGS. 1 to 10, and therefore the overlapping description will be omitted. In this embodiment, the polishing head system 1 includes an operation control unit 9. The polishing head system 1 of this embodiment further includes at least one pressure sensor 90 for measuring the pressure in at least one of the pressure chambers Cb1 to Cb6, and a rotary connector 92 for electrically connecting the pressure sensor 90 to the operation control unit 9. In this embodiment, the polishing head system 1 includes a pressure sensor 90 for measuring the pressure in the pressure chamber Cb1. In one embodiment, the polishing head system 1 may include two or more pressure sensors 90 for measuring the pressure in two or more of the pressure chambers Cb1 to Cb6. For example, the polishing head system 1 may include six pressure sensors 90 for measuring the pressure in the pressure chambers Cb1 to Cb6, respectively.

[0106] The pressure sensor 90 is attached to the fluid supply line Fb1 and is electrically connected to the operation control unit 9 via a rotary connector 92. The rotary connector 92 is attached to the head shaft 11. The pressure sensor 90 is configured to measure the pressure in the pressure chamber Cb1. The pressure in the pressure chamber Cb1 measured by the pressure sensor 90 is sent to the operation control unit 9. The pressure sensor 90 is configured to send a measured value of the pressure in the pressure chamber Cb1 to the operation control unit 9 at a predetermined time interval. In one embodiment, the pressure sensor 90 may be configured to include a secondary battery and a wireless communication function for wirelessly communicating with the operation control unit 9, and to be operable without the rotary connector 92.

[0107] In this embodiment, the set pressure values ​​of the compressed fluid in the fluid supply lines Fb1 to Fb6 are 0 (i.e., the set pressure values ​​in the pressure regions PR1, PR4, PR5, PR6) in the fluid supply lines Lb1, Lb4, Lb5, Lb6, and P5 (i.e., the set pressure values ​​in the pressure regions PR2, PR3) in the fluid supply lines Lb2, Lb3, as in the example shown in Fig. 21. The target pressure in this embodiment is 0 when the pressure chamber Cb1 is located in the pressure regions PR1 (0 degrees), PR4 (180 degrees), PR5 (240 degrees), PR6 (300 degrees), and P5 when the pressure chamber Cb1 is located in the pressure regions PR2 (60 degrees), PR3 (120 degrees).

[0108] The operation control unit 9 is configured to send a corrected set pressure value that is greater than the set pressure value of the compressed fluid in the fluid supply lines Fb1 to Fb6 to the pressure regulators Rb1 to Rb6 when the measured pressure value of the pressure chamber Cb1 sent from the pressure sensor 90 is smaller than the set pressure value, and to have the pressure regulators Rb1 to Rb6 correct the pressure in the pressure chamber Cb1 based on the corrected set pressure value. In this specification, the "corrected set pressure value is greater than the set pressure value" means that the corrected set pressure value of the compressed fluid in at least one of the fluid supply lines Lb1 to Lb6 is greater than the set pressure value. In this embodiment, the corrected set pressure value of the compressed fluid in the fluid supply lines Lb2 and Lb3 is greater than the set pressure value.

[0109] In this embodiment, the operation control unit 9 sends a corrected set pressure value 0, which is the same as the set pressure value 0, to the pressure regulators Rb1, Rb4, Rb5, and Rb6, and sends a corrected set pressure value P6, which is greater than the set pressure value P5, to the pressure regulators Rb2 and Rb3. When the corrected set pressure values ​​are sent from the operation control unit 9 to the pressure regulators Rb1 to Rb6, the pressures of the compressed fluid in the fluid supply lines Lb1, Lb4, Lb5, and Lb6 (i.e., the pressure values ​​in the pressure regions PR1, PR4, PR5, and PR6) become 0, and the pressures of the compressed fluid in the fluid supply lines Lb2 and Lb3 (i.e., the pressure values ​​in the pressure regions PR2 and PR3) become the corrected set pressure value P6, which is greater than the set pressure value P5.

[0110] Fig. 23 is a graph showing an embodiment of the target pressure, the corrected set pressure values ​​sent to the pressure regulators Rb1-Rb6, and the corrected pressure in one pressure chamber Cb1. The graph shown by the thin solid line in Fig. 23 represents the progress of the target pressure in one pressure chamber Cb1. The graph shown by the thick solid line in Fig. 23 represents the corrected set pressure values. The graph shown by the thick dashed line in Fig. 23 represents the progress of the pressure in one pressure chamber Cb1 when the pressure of the compressed fluid in the fluid supply lines Lb1-Lb6 is the corrected set pressure value. In other words, the graph shown by the thick dashed line represents the progress of the pressure in one pressure chamber Cb1 corrected by the operation control unit 9.

[0111] When the compressed fluid in the fluid supply line Lb1 is at the corrected set pressure value, the pressure in the pressure chamber Cb1 rises to a pressure P6' which is smaller than P6, which is the corrected set pressure value of the compressed fluid in the fluid supply line Lb1. In this embodiment, the corrected pressure P6' in the pressure chamber Cb1 when the pressure chamber Cb1 is located between the pressure regions PR2 and PR3 is greater than the target pressure P5 when the pressure chamber Cb1 is located in the pressure regions PR2 and PR3. The pressures in the other pressure chambers Cb2 to Cb6 are also corrected in the same manner as the pressure chamber Cb1.

[0112] The pressure sensor 90 is configured to measure the pressure in the pressure chamber Cb1. The pressure in the pressure chamber Cb1 measured by the pressure sensor 90 is sent to the operation control unit 9. The operation control unit 9 is configured to determine a corrected set pressure value that minimizes the difference between the pressure in the pressure chamber Cb1 measured by the pressure sensor 90 and a target pressure, and to send the determined corrected set pressure value to the pressure regulators Rb1 to Rb6. In this way, the operation control unit 9 can bring the pressure in the pressure chambers Cb1 to Cb6 closer to the target pressure by executing feedback control that determines the corrected set pressure values ​​of the pressure regulators Rb1 to Rb6 based on the pressure in the pressure chamber Cb1 measured by the pressure sensor 90.

[0113] In one embodiment, the operation control unit 9 is configured to determine a corrected set pressure value that minimizes the difference between the integral value of the pressure in the pressure chamber Cb1 during one rotation of the polishing head 10 and the integral value of the target pressure. As shown in Fig. 24, the area of ​​the region indicated by thin hatching represents the integral value of the target pressure during one rotation of the polishing head 10, and the area of ​​the region indicated by thick hatching represents the integral value of the pressure in the pressure chamber Cb1 during one rotation of the polishing head 10. The operation control unit 9 calculates the integral value of the pressure in the pressure chamber Cb1 during one rotation of the polishing head 10 and the integral value of the target pressure, and determines a corrected set pressure value that minimizes the difference between these integral values.

[0114] The operation control unit 9 can minimize the difference between the pressure in the pressure chamber Cb1 and the target pressure by sending the corrected set pressure value that minimizes the difference between the integral value of the pressure in the pressure chamber Cb1 during one rotation of the polishing head 10 and the integral value of the target pressure to the pressure regulators Rb1-Rb6. Therefore, it is possible to minimize the difference between the pressing force on the retaining ring 40 generated by the pressure chambers Cb1-Cb6 of the corrected pressure and the pressing force on the retaining ring 40 generated by the pressure chambers Cb1-Cb6 of the target pressure. As a result, the pressure chambers Cb1-Cb6 of the corrected pressure can apply a sufficient pressing force to the retaining ring 40.

[0115] In one embodiment, the operation control unit 9 may be configured to determine the corrected set pressure value based on a correlation between the set pressure value of the compressed fluid in the fluid supply lines Fb1-Fb6 and the pressure in the pressure chamber Cb1, which is previously acquired. As described with reference to FIG. 21, there is a correlation between the set pressure value of the compressed fluid in the fluid supply lines Fb1-Fb6 and the pressure in the pressure chamber Cb1 according to the rotation speed of the polishing head 10. This correlation can also be applied to the relationship between the corrected set pressure value and the corrected pressure in the pressure chamber Cb1.

[0116] The correlation between the set pressure values of the compressed fluid in the fluid supply lines Fb1 to Fb6 and the pressure in the pressure chamber Cb1 is stored in advance in the storage device 9a (see FIG. 1) of the operation control unit 9. The operation control unit 9 determines a corrected set pressure value that minimizes the difference between the pressure in the pressure chamber Cb1 and the target pressure based on the correlation between the set pressure values of the compressed fluid in the fluid supply lines Fb1 to Fb6 and the pressure in the pressure chamber Cb1 stored in the storage device 9a. Also in this embodiment, by correcting the pressures in the pressure chambers Cb1 to Cb6, the pressure chambers Cb1 to Cb6 can apply a sufficient pressing force to the retainer ring 40.

[0117] The set pressure value and the corrected set pressure value of this embodiment are examples, and the set pressure value and the corrected set pressure value are not limited to this embodiment. For example, as shown in FIG. 25, the set pressure values of the compressed fluid in the fluid supply lines Lb1 and Lb4 (i.e., the set pressure values in the pressure region PR1) are P8, and the set pressure values of the compressed fluid in the fluid supply lines Lb2 and Lb3 (i.e., the set pressure values in the pressure region PR2) are P9 (>P8), and the set pressure values of the compressed fluid in the fluid supply lines Lb5 and Lb6 (i.e., the set pressure values in the pressure region PR5) are P7 (<P8). In this case, the operation control unit 9 may send a corrected set pressure value P10 greater than the set pressure value P8 to the pressure regulators Lb1 and Lb4, send a corrected set pressure value P11 greater than the set pressure value P9 to the pressure regulators Rb2 and Rb3, and send the same set pressure value P7 as the set pressure value to the pressure regulators Lb5 and Lb6. In this embodiment, the corrected pressure P11' in the pressure chamber Cb1 when the pressure chamber Cb1 is located between the pressure region PR2 and the pressure region PR3 is greater than the target pressure P9 when the pressure chamber Cb1 is located in the pressure regions PR2 and PR3.

[0118] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0119] 1 Polishing Head System 2 Polishing Pads 2a Polished surface 3 Polishing table 5 Polishing fluid supply nozzle 7 Film Thickness Sensor 9. Operation control section 9a Storage device 9b Processing equipment 10 Polishing Head 11 Head shaft 11a External surface 14 Head swing shaft 16 Head swing arm 18 Head rotation mechanism 20 Rotary joint assembly 21A, 21B, 21C, 21D Rotary Joint 22a Inside 22b External surface 25 Multi-path rotary joint 25a Inside 25b External surface 28 Rotary joint 31 Career 34 Elastic Membrane 35 Board pressing surface 36A,36B,36C,36D Bulkhead 40 Retainer ring 42 Drive Ring 45A, 45B, 45C, 45D, 45E, 45F Retainer ring pressing membrane 51 Shaft passage 51a Shaft opening 51b Bent part 54 Joint flow path 54a Ring channel 54b Connection port 56 Shaft passage 56a Shaft opening 56b Bent part 58 Joint flow path 58a Joint opening 58b Connection port 60 Joint material 60a Spring retaining hole 60b Protrusion 62 Joint holder 62a Recess 62b Seal groove 62c Recess 63 Spacer 63a Protrusion 63b Through hole 65 Spring 68 Positioning Mechanism 70 Sealing mechanism 72 Endless seal member 75A, 75B, 75C, 75D, 75E, 75F Rolling diaphragm 76a Roll section 76b Pressing part 78 Pressure Chamber 79 Header 80 Annular rolling diaphragm 80a Roll section 80b Pressing part 81 Shaft passage 84 Joint flow path 90 Pressure Sensor 92 Rotary connector for pressure sensor Ca1, Ca2, Ca3, Ca4 pressure chamber Cb1, Cb2, Cb3, Cb4, Cb5, Cb6 Pressure chamber Cc Annular pressure chamber Cg1, Cg2, Cg3, Cg4, Cg5, Cg6 Pressure Chamber Group Fa1, Fa2, Fa3, Fa4 fluid transfer lines Fb1, Fb2, Fb3, Fb4, Fb5, Fb6 Fluid transfer lines Fc Fluid transfer line La1, La2, La3, La4 Fluid supply lines Lb1, Lb2, Lb3, Lb4, Lb5, Lb6 Fluid supply lines Lc Fluid supply line PR1,PR2,PR3,PR4,PR5,PR6 Pressure range Ra1,Ra2,Ra3,Ra4 Pressure Regulators Rb1, Rb2, Rb3, Rb4, Rb5, Rb6 Pressure regulators Rc Pressure Regulator

Claims

1. A polishing head that presses the substrate against the polishing surface, A head shaft connected to the polishing head, A head rotation mechanism that rotates the polishing head together with the head shaft, A multipath rotary joint is positioned to surround at least a portion of the head shaft, A fluid supply line connected to the multipath rotary joint, The fluid supply line is equipped with a pressure regulator, The polishing head is A substrate pressing surface for pressing the substrate against the polishing surface, A retainer ring is arranged to surround the substrate pressing surface, It is made of an elastic material and has a plurality of pressure chambers that generate a pressing force for pressing the retainer ring against the polished surface, The head shaft has a plurality of shaft passages that communicate with each of the plurality of pressure chambers, The multipath rotary joint is configured to sequentially connect the fluid supply line to the plurality of shaft passages each time the head shaft rotates once. The polishing head system comprises a plurality of pressure chambers arranged along the circumferential direction of the retainer ring.

2. The plurality of shaft passages have a plurality of shaft openings that open on the outer surface of the head shaft, The multipath rotary joint has a joint channel that communicates with the fluid supply line, The joint channel has a joint opening that opens on the inner surface of the multipath rotary joint, The plurality of shaft openings are arranged along the circumferential direction of the head shaft, The polishing head system according to claim 1, wherein the plurality of shaft openings and the joint opening are located at the same position in the axial direction of the head shaft.

3. The aforementioned fluid supply line is a plurality of fluid supply lines, The pressure regulator is a plurality of pressure regulators attached to each of the plurality of fluid supply lines, The aforementioned joint channel is a plurality of joint channels that communicate with each of the plurality of fluid supply lines, The polishing head system according to claim 2, wherein the joint openings are a plurality of joint openings arranged along the circumferential direction of the head shaft.

4. The aforementioned multipath rotary joint is A joint member arranged along the circumferential direction of the head shaft, A joint holder is arranged to surround the aforementioned joint member, The joint member has a spring that presses it against the head shaft, The polishing head system according to claim 2, wherein the joint channel extends through the joint member and the joint holder.

5. The polishing head system according to claim 4, wherein the multipath rotary joint has a positioning mechanism for fixing the relative position of the joint member in the circumferential direction with respect to the joint holder.

6. The aforementioned multiple pressure chambers are a group of multiple pressure chambers, The aforementioned multiple pressure chamber groups are each in communication with the aforementioned multiple shaft passages, The polishing head system according to claim 1, wherein each of the plurality of pressure chamber groups includes a plurality of pressure chambers formed by a plurality of rolling diaphragms arranged along the circumferential direction of the retainer ring.

7. The polishing head system according to claim 6, wherein each of the plurality of rolling diaphragms has a cylindrical shape.

8. The polishing head system according to claim 1, wherein the polishing head further comprises an annular pressure chamber adjacent to the plurality of pressure chambers.

9. The polishing head system according to claim 2, wherein the width of the joint opening is greater than the width of the plurality of shaft openings.

10. The system further comprises an operation control unit that controls the operation of the pressure regulator, The plurality of pressure chambers include a first pressure chamber, The polishing head system according to claim 1, wherein the operation control unit is configured to send a correction set pressure value greater than the set pressure value of the fluid in the fluid supply line to the pressure regulator when the pressure in the first pressure chamber is less than the target pressure, causing the pressure regulator to correct the pressure in the first pressure chamber.

11. The polishing head system according to claim 10, wherein the operation control unit is configured to determine the correction setting pressure value that minimizes the difference between the integral value of the pressure in the first pressure chamber during one rotation of the polishing head and the integral value of the target pressure.

12. The polishing head system further includes a pressure sensor for measuring the pressure in the first pressure chamber, The polishing head system according to claim 10, wherein the operation control unit is configured to determine the correction setting pressure value that minimizes the difference between the pressure in the first pressure chamber measured by the pressure sensor and the target pressure.

13. The polishing head system according to claim 10, wherein the operation control unit is configured to determine the corrected set pressure value that minimizes the difference between the pressure in the first pressure chamber and the target pressure, based on the correlation between the previously acquired set pressure value and the pressure in the first pressure chamber.

14. A method for polishing a substrate using the polishing head system described in any one of claims 1 to 13, While rotating the substrate, the substrate is pressed against the polishing surface to polish the substrate. During the polishing of the substrate, each time the head shaft is rotated, the fluid supply line is sequentially connected to the plurality of shaft passages, and fluid is supplied to the plurality of pressure chambers through the fluid supply line, thereby applying a plurality of pressing forces to the retainer ring and pressing the retainer ring against the polishing surface. A polishing method wherein the plurality of pressing forces include at least two different pressing forces.

15. The polishing of the substrate is performed while rotating the polishing surface. The polishing method according to claim 14, wherein the pressure regulator adjusts the pressures in the plurality of pressure chambers such that the pressing force generated by the pressure chamber located downstream in the rotational direction of the polishing surface is greater than the pressing force generated by the other pressure chambers.

16. The polishing method according to claim 14, further comprising the pressure regulator correcting the pressure in the first pressure chamber, which is included in the plurality of pressure chambers, based on a corrected set pressure value that is greater than the set pressure value of the fluid in the fluid supply line, when the pressure in the first pressure chamber is less than the target pressure.

17. The polishing method according to claim 16, further comprising determining the correction setting pressure value that minimizes the difference between the integral value of the pressure in the first pressure chamber during one rotation of the polishing head and the integral value of the target pressure.

18. The pressure inside the first pressure chamber is measured using a pressure sensor. The polishing method according to claim 16, further comprising determining the correction setting pressure value that minimizes the difference between the pressure in the first pressure chamber measured by the pressure sensor and the target pressure.

19. The polishing method according to claim 16, further comprising determining the corrected set pressure value that minimizes the difference between the pressure in the first pressure chamber and the target pressure, based on the correlation between the previously acquired set pressure value and the pressure in the first pressure chamber.

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