JP6445924B2 - Polishing equipment - Google Patents

Description

  The present invention relates to a polishing apparatus for polishing a substrate such as a wafer, and more particularly to a polishing apparatus provided with a retainer ring surrounding the periphery of the substrate.

  In recent years, with higher integration and higher density of semiconductor devices, circuit wiring has become increasingly finer and the number of layers of multilayer wiring has increased. When trying to realize multilayer wiring while miniaturizing the circuit, the step becomes larger while following the surface unevenness of the lower layer, so as the number of wiring layers increases, the film coverage to the step shape in thin film formation (Step coverage) deteriorates. Therefore, in order to carry out multilayer wiring, it is necessary to improve the step coverage and perform a flattening process in an appropriate process. Further, since the depth of focus becomes shallower as the optical lithography becomes finer, it is necessary to planarize the surface of the semiconductor device so that the uneven steps on the surface of the semiconductor device are kept below the depth of focus.

Therefore, in the semiconductor device manufacturing process, planarization of the surface of the semiconductor device has become increasingly important. The most important technique for planarizing the surface is chemical mechanical polishing (CMP). In this chemical mechanical polishing, polishing is performed by bringing a wafer into sliding contact with the polishing surface while supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto the polishing surface of the polishing pad.

  A polishing apparatus for performing CMP includes a polishing table that supports a polishing pad, a polishing head for holding a wafer, and a polishing liquid supply nozzle that supplies a polishing liquid (slurry) onto the polishing pad. The polishing pad is rotated together with the polishing table, and the polishing liquid is supplied onto the rotating polishing pad. The polishing head holds the wafer and presses the wafer against the polishing surface of the polishing pad with a predetermined pressure. The surface of the wafer is polished by a mechanical action by abrasive grains contained in the polishing liquid and a chemical action by chemical components contained in the polishing liquid.

  If the relative pressing force between the wafer being polished and the polishing surface of the polishing pad is not uniform over the entire surface of the wafer, insufficient polishing or overpolishing may occur depending on the pressing force applied to each part of the wafer. It will occur. Therefore, in order to equalize the pressing force on the wafer, a pressure chamber formed of an elastic film is provided at the lower portion of the polishing head, and fluid such as air is supplied to the pressure chamber by the fluid pressure through the elastic film. Pressing the wafer is performed.

  Since the polishing pad has elasticity, the pressing force applied to the edge portion (peripheral portion) of the wafer being polished becomes non-uniform, so that only the edge portion of the wafer is polished, so-called “edge fringing” occurs. There is a case. In order to prevent such edge fringing, a retainer ring that holds the edge portion of the wafer is provided so as to be movable up and down with respect to the head body, and the polishing surface of the polishing pad located on the outer peripheral edge side of the wafer is pressed by the retainer ring. I have to.

  Since the retainer ring presses the polishing pad around the wafer, the load of the retainer ring affects the profile of the edge portion of the wafer. In order to actively control the profile of the edge portion of the wafer, a local load may be applied to a part of the retainer ring. FIG. 10 is a view of a mechanism for applying a local load to a part of the retainer ring 200 as viewed from above the retainer ring 200. As shown in FIG. 10, an annular rail 201 is fixed to the upper surface of the retainer ring 200, and three rollers 205 are arranged on the annular rail 201. An annular groove 201a is formed on the upper surface of the annular rail 201, and the roller 205 is placed in the annular groove 201a.

  FIG. 11 is a perspective view showing the annular rail 201 and the roller 205 disposed thereon. In FIG. 11, the retainer ring 200 is not shown. One of the three rollers 205 is connected to a load generator (not shown), and a downward local load is applied to the roller 205 as shown in FIG. During the polishing of the wafer, the annular rail 201 rotates integrally with the retainer ring 200, but the positions of the three rollers 205 are fixed. Therefore, these rollers 205 are in rolling contact with the rotating annular rail 201.

  When the annular rail 201 rotates with the retainer ring 200, the annular rail 201 is entirely annular, so that the rollers 205 are caused by the speed difference between the inner and outer portions of each roller 205. Slightly slip. Further, when the annular rail 201 is rotating, the side surface of each roller 205 is in contact with the annular groove 201 a of the annular rail 201. Due to such sliding and contact of the roller 205, the roller 205 is worn and wear powder is generated. As the wear further proceeds, the roller 205 is damaged. When the wear powder falls on the polishing pad, the surface of the wafer is damaged during the polishing of the wafer, causing a wafer defect.

JP 2014-4675 A

  Then, an object of this invention is to provide the grinding | polishing apparatus which can suppress abrasion of the roller which transmits a load to a retainer ring.

  One aspect of the present invention is a head body that is pressed against a polishing surface while rotating a substrate, a retainer ring that is disposed so as to surround the substrate and that presses the polishing surface while rotating together with the head body, and is fixed to the retainer ring. A rotating ring that rotates together with the retainer ring, a stationary ring disposed on the rotating ring, and a local load applying device that applies a local load to a part of the retainer ring via the rotating ring and the stationary ring. And the rotating ring has a plurality of rollers in contact with the stationary ring.

In a preferred aspect of the present invention, each of the plurality of rollers includes a bearing and a wheel attached to an outer ring of the bearing, and the wheel is made of resin or rubber.
In a preferred aspect of the present invention, the rotating ring includes a roller housing formed with an annular recess in which the plurality of rollers are accommodated.
A preferred aspect of the present invention further includes a suction line connected to the stationary ring, and the suction line communicates with a space formed by the annular recess.

A preferred aspect of the present invention further includes a seal disposed between the rotating ring and the stationary ring.
In a preferred aspect of the present invention, the seal is a labyrinth seal.
In a preferred aspect of the present invention, the seal is a contact-type seal that closes a gap between the rotating ring and the stationary ring.
In a preferred aspect of the present invention, the stationary ring includes an annular rail that contacts the plurality of rollers.

  According to the present invention, while a plurality of rollers rotate with the retainer ring, a load is transmitted to a part of the retainer ring. Each roller receives a load only when passing through the point of application of the load. Therefore, the time for which each roller receives a load is shortened, and wear of the roller is suppressed. Further, the generation of wear powder is suppressed, and the life of the roller is extended.

It is a mimetic diagram showing the polish device in one embodiment of the present invention. It is a perspective view which shows a local load provision apparatus. It is sectional drawing of a grinding | polishing head. It is sectional drawing of a rotation ring and a stationary ring. It is a perspective view which shows a roller and an annular rail. It is the figure which looked at the roller and annular rail shown in FIG. 5 from the bottom. It is sectional drawing which shows a contact-type seal | sticker. It is a figure which shows the suction system for attracting | sucking abrasion powder from a grinding | polishing head. It is an expanded sectional view of a suction line, a stationary ring, and a rotation ring. It is the figure which looked at the mechanism which gives a local load to a part of retainer ring from the retainer ring. It is a perspective view which shows an annular rail and the roller arrange | positioned on it.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic diagram showing a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing head (substrate holding apparatus) 1 that holds and rotates a wafer that is an example of a substrate, a polishing table 3 that supports a polishing pad 2, and a polishing liquid ( And a polishing liquid supply nozzle 5 for supplying a slurry. The upper surface of the polishing pad 2 constitutes a polishing surface 2a for polishing the wafer.

  The polishing head 1 is connected to the lower end of the polishing head shaft 11. The polishing head shaft 11 is rotatably held by a head arm 16. A rotating device (not shown) for rotating the polishing head shaft 11 and a lifting device (not shown) for raising and lowering the polishing head shaft 11 are arranged in the head arm 16. The polishing head 1 is rotated via a polishing head shaft 11 by a rotating device, and the polishing head 1 is raised and lowered via the polishing head shaft 11 by an elevating mechanism. The head arm 16 is fixed to the turning shaft 15, and the polishing head 1 can be moved to the outside of the polishing table 3 by the rotation of the turning shaft 15.

  The polishing head 1 is configured to hold the wafer on the lower surface thereof by vacuum suction. The polishing head 1 and the polishing table 3 rotate in the same direction as indicated by arrows, and in this state, the polishing head 1 presses the wafer against the polishing surface 2 a of the polishing pad 2. A polishing liquid is supplied onto the polishing pad 2 from the polishing liquid supply nozzle 5, and the wafer is polished by sliding contact with the polishing pad 2 in the presence of the polishing liquid.

  The polishing head 1 includes a head main body 10 that presses the wafer against the polishing pad 2 and a retainer ring 20 that is disposed so as to surround the wafer. The head body 10 and the retainer ring 20 are configured to rotate integrally with the polishing head shaft 11. The retainer ring 20 is configured to be movable up and down independently of the head body 10. The retainer ring 20 projects outward from the head body 10 in the radial direction. A local load applying device 30 that applies a local load to a part of the retainer ring 20 is disposed above the retainer ring 20.

  The local load applying device 30 is fixed to the head arm 16. The retainer ring 20 during polishing rotates around its axis, but the local load applying device 30 does not rotate integrally with the retainer ring 20, and its position is fixed. On the upper surface of the retainer ring 20, a rotating ring 51 having a plurality of rollers (described later) disposed therein is fixed. Further, a stationary ring 91 is placed on the rotating ring 51. The stationary ring 91 is connected to the local load applying device 30.

  The rotating ring 51 rotates together with the retainer ring 20, but the stationary ring 91 does not rotate and its position is fixed. The local load applying device 30 applies a downward local load to a part of the retainer ring 20 via the stationary ring 91 and the rotating ring 51. The downward local load is transmitted to the retainer ring 20 through the stationary ring 91 and the rotating ring 51, and the retainer ring 20 presses the polishing surface 2 a of the polishing pad 2. The reason why a downward local load is applied to a part of the retainer ring 20 during polishing of the wafer is to positively control the peripheral edge (edge) profile of the wafer.

  FIG. 2 is a perspective view showing the local load applying device 30. As shown in FIG. 2, the local load applying device 30 includes two pressing rods 31, a bridge 32, a plurality of air cylinders (load generating devices) 33, 34, 35, a plurality of linear guides 38, a plurality of guide rods 39, The unit base 40 is mainly configured.

  The unit base 40 is fixed to the head arm 16. A plurality of (three in the illustrated example) air cylinders 33, 34, 35 and a plurality of (four in the illustrated example) linear guides 38 are attached to the unit base 40. The piston rods 33 a, 34 a, 35 a of the air cylinders 33, 34, 35 and the plurality of guide rods 39 are connected to a common bridge 32. The plurality of guide rods 39 are supported by a linear guide 38 so as to be movable up and down with low friction. By these linear guides 38, the bridge 32 can be moved up and down smoothly without tilting.

  The air cylinders 33, 34, and 35 are respectively connected to an independent pressure adjusting device (not shown) and an atmosphere release mechanism (not shown), and are configured to be able to generate loads independently of each other. Loads generated by the air cylinders 33, 34, and 35 are transmitted to the common bridge 32. The bridge 32 is connected to the stationary ring 91 by a pressing rod (pressing member) 31, and the pressing rod 31 transmits the load of the air cylinders 33, 34, and 35 applied to the bridge 32 to the stationary ring 91. The reason why there are three air cylinders is that the local load is located below the head arm 16 and the air cylinder cannot be placed directly above it. This is to match the position of the load. In the present embodiment, there are three cylinders. However, by strengthening the linear guide mechanism, only one cylinder may be provided, or a cylinder may be disposed under the head arm 16.

  The polishing head 1 rotates about its own axis, but the local load applying device 30 is fixed to the head arm 16 and therefore does not rotate with the polishing head 1. That is, during polishing of the wafer, the polishing head 1 and the wafer are rotating, while the local load applying device 30 is stationary at a predetermined position. Similarly, during the polishing of the wafer, the rotating ring 51 rotates together with the polishing head 1, while the stationary ring 91 is stationary at a predetermined position.

  Next, the polishing head 1 as a substrate holding device will be described. FIG. 3 is a cross-sectional view of the polishing head 1. The polishing head 1 includes a head body 10 and a retainer ring 20. The head body 10 moves the carrier 43 connected to the polishing head shaft 11 (see FIG. 1), the elastic membrane (membrane) 45 attached to the lower surface of the carrier 43, and the tilting and vertical movement of the retainer ring 20 with respect to the carrier 43. A spherical bearing 47 that supports the retainer ring 20 while being allowed is provided. The retainer ring 20 is connected to and supported by the spherical bearing 47 via a connecting member 75. The connecting member 75 is disposed in the carrier 43 so as to be movable up and down.

  The lower surface of the elastic film 45 constitutes a circular substrate contact surface, and this substrate contact surface is in contact with the upper surface of the wafer W (the surface opposite to the surface to be polished). A plurality of through holes (not shown) are formed in the substrate contact surface of the elastic film 45. A pressure chamber 46 is formed between the carrier 43 and the elastic film 45. The pressure chamber 46 is connected to a pressure adjusting device (not shown). When pressurized fluid (for example, pressurized air) is supplied to the pressure chamber 46, the elastic film 45 that receives the fluid pressure in the pressure chamber 46 presses the wafer W against the polishing surface 2 a of the polishing pad 2. When a negative pressure is formed in the pressure chamber 46, the wafer W is held on the lower surface of the elastic film 45 by vacuum suction.

  The retainer ring 20 is disposed so as to surround the wafer W and the elastic film 45. The retainer ring 20 includes a ring member 20a that comes into contact with the polishing pad 2, and a drive ring 20b fixed to the upper portion of the ring member 20a. The ring member 20a is coupled to the drive ring 20b by a plurality of bolts (not shown). The ring member 20a is disposed so as to surround the outer peripheral edge of the wafer W.

  The connecting member 75 includes a shaft portion 76 disposed in the center portion of the head body 10 and a plurality of spokes 78 extending radially from the shaft portion 76. The shaft portion 76 extends in the vertical direction within the spherical bearing 47 disposed at the center of the head body 10. The shaft portion 76 is supported by the spherical bearing 47 so as to be movable in the vertical direction. The drive ring 20b is connected to the spoke 78. With such a configuration, the connecting member 75 and the retainer ring 20 connected thereto can be moved in the vertical direction with respect to the head body 10.

  The spherical bearing 47 includes an inner ring 48 and an outer ring 49 that slidably supports the outer peripheral surface of the inner ring 48. The inner ring 48 is connected to the retainer ring 20 via a connecting member 75. The outer ring 49 is fixed to the carrier 43. The shaft portion 76 of the connecting member 75 is supported by the inner ring 48 so as to be movable up and down. The retainer ring 20 is supported by a spherical bearing 47 via a connecting member 75 so as to be tiltable.

  The spherical bearing 47 allows the retainer ring 20 to move up and down and tilt, while restricting lateral movement (horizontal movement) of the retainer ring 20. During polishing of the wafer W, the retainer ring 20 receives a lateral force (a force directed outward in the radial direction of the wafer W) from the wafer W due to friction between the wafer W and the polishing pad 2. This lateral force is received by the spherical bearing 47. As described above, the spherical bearing 47 is subjected to the lateral force that the retainer ring 20 receives from the wafer W due to the friction between the wafer W and the polishing pad 2 during the polishing of the wafer W (toward the radial outside of the wafer W). The retainer ring 20 functions as a support mechanism that restricts the lateral movement of the retainer ring 20 (that is, fixes the horizontal position of the retainer ring 20).

  A plurality of pairs of driving collars 80 are fixed to the carrier 43. Each pair of drive collars 80 is disposed on both sides of each spoke 78, and the rotation of the carrier 43 is transmitted to the retainer ring 20 via the drive collar 80, whereby the head body 10 and the retainer ring 20 are integrated. Rotate. The drive collar 80 is only in contact with the spoke 78 and does not prevent the connecting member 75 and the retainer ring 20 from moving up and down and tilting.

  The upper part of the retainer ring 20 is connected to an annular retainer ring pressing mechanism 60. The retainer ring pressing mechanism 60 applies a uniform downward load to the entire upper surface of the retainer ring 20 (more specifically, the upper surface of the drive ring 20b). ) Is pressed against the polishing surface 2 a of the polishing pad 2.

  The retainer ring pressing mechanism 60 includes an annular piston 61 fixed to the upper part of the drive ring 20 b and an annular rolling diaphragm 62 connected to the upper surface of the piston 61. A pressure chamber 63 is formed inside the rolling diaphragm 62. The pressure chamber 63 is connected to a pressure adjusting device (not shown). When pressurized fluid (for example, pressurized air) is supplied to the pressure chamber 63, the rolling diaphragm 62 pushes down the piston 61 downward, and the piston 61 pushes down the entire retainer ring 20 downward. In this way, the retainer ring pressing mechanism 60 presses the lower surface of the retainer ring 20 against the polishing surface 2 a of the polishing pad 2.

  A rotating ring 51 is fixed to the upper surface of the retainer ring 20. Further, a stationary ring 91 is disposed on the rotating ring 51. The lower end of the pressing rod 31 of the local load applying device 30 is connected to the stationary ring 91. The local load applying device 30 applies a downward local load to the stationary ring 91 through the pressing rod 31. While the wafer is being polished, the rotating ring 51 rotates together with the retainer ring 20, but the local load applying device 30 and the stationary ring 91 do not rotate.

  FIG. 4 is a cross-sectional view of the rotating ring 51 and the stationary ring 91. The rotating ring 51 includes a plurality of rollers 52, a roller shaft 54 that supports each of the rollers 52, and a roller housing 55 to which the roller shaft 54 is fixed. The roller housing 55 has an annular shape and is fixed to the upper surface of the retainer ring 20. The roller 52 has a bearing 57 attached to the roller shaft 54, and the roller 52 is rotatable about the roller shaft 54.

  The stationary ring 91 includes an annular rail 92 that contacts the top of the roller 52 and an annular rail base 94 to which the annular rail 92 is fixed. An annular groove 95 is formed on the lower surface of the annular rail 92, and the top of each roller 52 is in contact with the annular groove 95. A pressing rod 31 is connected to the upper portion of the rail base 94.

  FIG. 5 is a perspective view showing the roller 52 and the annular rail 92, and FIG. 6 is a view of the roller 52 and the annular rail 92 shown in FIG. 5 as viewed from below. In the present embodiment, 24 rollers 52 are provided. During wafer polishing, these rollers 52 rotate integrally with the retainer ring 20, while the annular rail 92 is stationary. Accordingly, each roller 52 is in rolling contact with the annular rail 92.

  The load of the local load applying device 30 is transmitted from the annular rail 92 to the roller 52. Since the roller 52 receives the load of the local load applying device 30 only when passing through the point of application of the load, the time during which the load is applied to each roller 52 is compared with the conventional configuration shown in FIG. 10 in which the position of the roller is fixed. Become shorter. Therefore, the life of each roller 52 can be further extended.

  The number of rollers 52 is determined based on the outer diameter of the rollers 52 and the diameter of the annular rail 92. In order to transmit the load smoothly, it is better to increase the number of rollers 52 as much as possible so that the interval between the rollers 52 is reduced. The roller 52 has a smooth outer peripheral surface, and is in contact with the annular rail 92 with a wide contact area so that a larger load can be transmitted. An annular rail 92 is placed on the roller 52. The roller 52 is in rolling contact with the annular rail 92. The lateral position of the annular rail 92 is guided by contact between the corners of the curved cross section of the roller 52 and the corners of the curved cross section of the annular rail 92. In this case, the load of the local load applying device 30 is mainly transmitted from the annular rail 92 to the outer peripheral surface of the roller 52.

  As shown in FIG. 4, the roller shaft 54 penetrating the inner ring of the bearing 57 of the roller 52 is supported by the inner wall and the outer wall of the roller housing 55 and fixed by screws 58 inserted into the inner wall. . Therefore, a female screw is formed on the roller shaft 54, and a groove 54a into which a minus driver is fitted is formed on the opposite side of the female screw so as not to idle when the screw 58 is fastened. The rotating ring 51 is placed on the upper surface of the drive ring 20 b of the retainer ring 20. The drive ring 20 b and the rotating ring 51 are positioned by positioning pins (not shown), and the rotating ring 51 does not slip with respect to the retainer ring 20.

  The roller 52 includes a bearing 57 attached to the roller shaft 54 and a wheel 59 fixed to the outer ring of the bearing 57. The wheel 59 is made of a material having high wear resistance, such as polyacetal, PET (polyethylene terephthalate), PPS (polyethylene sulfide), MC nylon (registered trademark), or the like. The material of the annular rail 92 is preferably a metal with high corrosion resistance such as stainless steel (SUS304). A single row deep groove ball bearing is used as the bearing 57, and the wheel 59 is attached to the bearing 57 by press-fitting a resin wheel 59 into the outer ring of the bearing 57. With such a configuration, the roller 52 can rotate smoothly and can transmit a load without damaging the annular rail 92.

  An annular recess 55a is formed inside the roller housing 55, and a plurality of rollers 52 are accommodated in the annular recess 55a. The lower surface and both side surfaces of each roller 52 are surrounded by an annular recess 55a. Seals 100 </ b> A and 100 </ b> B are disposed between the roller housing 55 of the rotating ring 51 and the rail base 94 of the stationary ring 91. More specifically, an outer seal 100 </ b> A is disposed outside the annular rail 92, and an inner seal 100 </ b> B is disposed inside the annular rail 92. There are no openings on both side surfaces and the bottom surface of the annular recess 55a, and seals 100A and 100B are disposed between the stationary ring 91 and the rotating ring 51. Therefore, the abrasion powder generated from the roller 52 and the annular rail 92 is confined in the annular recess 55a and does not fall on the polishing pad 2.

  In the embodiment shown in FIG. 4, the outer seal 100A and the inner seal 100B are labyrinth seals. The outer seal 100 </ b> A includes a first peripheral wall 101 disposed outside the annular rail 92 and a second peripheral wall 102 disposed outside the first peripheral wall 101. The first peripheral wall 101 extends upward from the roller housing 55 and is formed integrally with the roller housing 55. The second peripheral wall 102 extends downward from the rail base 94 and is formed integrally with the rail base 94. A very small gap is formed between the first peripheral wall 101 and the second peripheral wall 102. Similarly, the inner seal 100 </ b> B includes a first peripheral wall 101 disposed inside the annular rail 92 and a second peripheral wall 102 disposed inside the first peripheral wall 101.

  As another embodiment, as shown in FIG. 7, the outer seal 100 </ b> A may be a contact-type seal that closes a gap between the stationary ring 91 and the rotating ring 51. The contact seal includes a peripheral wall 104 disposed outside the annular rail 92 and a lip seal 105 disposed outside the peripheral wall 104. The peripheral wall 104 extends upward from the roller housing 55 and is formed integrally with the roller housing 55. The lip seal 105 extends downward from the rail base 94 and is made of an elastic material such as rubber or silicone. The end of the lip seal 105 is in contact with the peripheral wall 104. Therefore, no gap is formed between the peripheral wall 104 and the lip seal 105, and the wear powder is completely prevented from coming out of the annular recess 55a. Not only the outer seal 100A but also the inner seal 100B may be a contact seal.

  Next, a suction system for sucking abrasion powder from the polishing head 1 will be described with reference to FIG. As shown in FIG. 8, the polishing apparatus includes a suction line 108 connected to a vacuum source (for example, a vacuum pump) P. The tip of the suction line 108 is connected to the stationary ring 91.

  FIG. 9 is an enlarged cross-sectional view of the suction line 108, the stationary ring 91, and the rotating ring 51. As shown in FIG. 9, a through hole 109 penetrating in the vertical direction is formed in the annular rail base 94 and the annular rail 92 constituting the stationary ring 91. The through hole 109 communicates with a space 110 formed by the annular recess 55 a of the roller housing 55. The plurality of rollers 52 are accommodated in the annular recess 55a.

  The suction line 108 is connected to the through hole 109 formed in the stationary ring 91, and therefore the suction line 108 communicates with the space 110 formed by the annular recess 55a. As described above, since the roller 52 is in rolling contact with the annular rail 92, wear powder is generated. Most of the wear powder is received in the annular recess 55a, and leakage to the outside is minimized. The suction line 108 sucks the wear powder existing in the annular recess 55a and removes the wear powder from the roller housing 55 (that is, the rotating ring 51).

  The through hole 109 formed in the annular rail 92 may promote wear of the roller 52. Therefore, the through hole 109 is preferably provided at a position where the load applied to the roller 52 from the annular rail 92 is the smallest. Ideally, as shown in FIG. 8, the through hole 109 is preferably located on the opposite side of the pressing rod (pressing member) 31. A plurality of suction lines 108 may be provided. In order to improve maintenance work, the suction line 108 is preferably removable from the stationary ring 91. In this case, it is preferable to provide a seal (for example, an O-ring) for sealing the gap between the suction line 108 and the stationary ring 91.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

1 Polishing head (substrate holding device)
DESCRIPTION OF SYMBOLS 2 Polishing pad 2a Polishing surface 3 Polishing table 5 Polishing liquid supply nozzle 10 Head main body 11 Polishing head shaft 15 Revolving shaft 20 Retainer ring 20a Ring member 20b Drive ring 30 Local load-applying device 31 Press rod 32 Bridges 33, 34, 35 Air cylinder (Load generator)
38 Linear guide 39 Guide rod 40 Unit base 43 Carrier 45 Elastic membrane (membrane)
46 Pressure chamber 47 Spherical bearing 48 Inner ring 49 Outer ring 51 Rotating ring 52 Roller 54 Roller shaft 55 Roller housing 55a Annular recess 57 Bearing 58 Screw 59 Wheel 60 Retainer ring pressing mechanism 61 Piston 62 Rolling diaphragm 63 Pressure chamber 75 Connecting member 76 Shaft 78 Spoke 80 Driving collar 91 Stationary ring 92 Ring rail 94 Rail base 95 Annular groove 100A Outer seal 100B Inner seal 101 First peripheral wall 102 Second peripheral wall 104 Peripheral wall 105 Lip seal 108 Suction line 109 Through hole

Claims (8)

A head body pressed against the polishing surface while rotating the substrate;
A retainer ring disposed so as to surround the substrate and pressing the polishing surface while rotating together with the head body;
A rotating ring fixed to the retainer ring and rotating together with the retainer ring;
A stationary ring disposed on the rotating ring;
A local load applying device that applies a local load to a part of the retainer ring via the rotating ring and the stationary ring;
The polishing apparatus according to claim 1, wherein the rotating ring has a plurality of rollers in contact with the stationary ring.   2. The polishing apparatus according to claim 1, wherein each of the plurality of rollers includes a bearing and a wheel attached to an outer ring of the bearing, and the wheel is made of resin or rubber.   The polishing apparatus according to claim 1, wherein the rotating ring includes a roller housing in which an annular recess in which the plurality of rollers are accommodated is formed. A suction line connected to the stationary ring;
The polishing apparatus according to claim 3, wherein the suction line communicates with a space formed by the annular recess.   The polishing apparatus according to claim 1, further comprising a seal disposed between the rotating ring and the stationary ring.   The polishing apparatus according to claim 4, wherein the seal is a labyrinth seal.   The polishing apparatus according to claim 5, wherein the seal is a contact-type seal that closes a gap between the rotating ring and the stationary ring.   The polishing apparatus according to claim 1, wherein the stationary ring includes an annular rail that contacts the plurality of rollers.

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