JP2015033759A - Polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing apparatus that can remove slurry entered into a gap between an elastic membrane to press a substrate, such as a wafer, and a retainer ring.SOLUTION: A polishing apparatus comprises: a membrane, i.e., an elastic membrane 46, that forms a pressure chamber to press a substrate onto a polishing pad; a top ring (substrate holding part) 1 that is arranged around the elastic membrane 46 and provided with a retainer ring 42 to press the polishing pad; a top ring rotating device to rotate the top ring 1 about its shaft center; and a cleaning brush 111 that comes into contact with the lower surface peripheral edge and outer peripheral surface of the elastic membrane 46.

Description

  The present invention relates to a polishing apparatus, and more particularly to a polishing apparatus that polishes the surface of a substrate such as a wafer.

  A polishing apparatus for polishing the surface of a wafer generally includes a polishing table that supports a polishing pad having a polishing surface, and a top ring that holds the wafer. While rotating the polishing table and the top ring, the top ring presses the wafer against the polishing surface of the polishing pad with a predetermined pressure and polishes the surface of the wafer by sliding the wafer against the polishing surface. In chemical mechanical polishing (CMP), a polishing liquid (slurry) is supplied to the polishing surface during polishing.

  In such a polishing apparatus, if the relative pressing force between the wafer and the polishing surface of the polishing pad is not uniform over the entire surface of the wafer, insufficient polishing or overpolishing occurs in the surface of the wafer. . Therefore, in order to equalize the pressing force on the wafer, a pressure chamber formed of an elastic film is provided at the lower part of the top ring, and fluid such as air is supplied to the pressure chamber by the fluid pressure through the elastic film. Pressing the wafer is performed.

  During the polishing of the wafer, a frictional force acts between the wafer and the polishing pad. In order to prevent the wafer from being detached from the top ring by this frictional force, a retainer ring that holds the position of the wafer is arranged. The retainer ring is disposed so as to surround the elastic film and the wafer, and presses the polishing pad around the wafer.

JP 2004-122291 A JP 2006-80138 A

  When the wafer is polished in the presence of the slurry, the slurry adheres to the elastic film of the top ring. The slurry adhering to the elastic film may eventually solidify, and the solid slurry may fall on the polishing surface and damage the surface of the wafer. Therefore, in the conventional polishing apparatus, the fluid is sprayed onto the elastic film to remove the slurry. However, it is difficult to remove the solidified slurry from the elastic film by the jet of fluid, and it is particularly difficult to remove the slurry present in the gap between the retainer ring and the elastic film.

  The present invention has been made in view of the above-described conventional problems, and provides a polishing apparatus capable of removing slurry that has entered a gap between an elastic film that presses a substrate such as a wafer and a retainer ring. Objective.

  In order to achieve the above-described object, one embodiment of the present invention includes a polishing table for supporting a polishing pad, an elastic film that forms a pressure chamber that presses a substrate against the polishing pad, and a periphery of the elastic film. A top ring provided with a retainer ring that presses the polishing pad, a top ring rotating device that rotates the top ring about its axis, and a cleaning that contacts the peripheral edge and the outer peripheral surface of the lower surface of the elastic film A polishing apparatus comprising a brush.

In a preferred aspect of the present invention, a cleaning liquid supply nozzle for supplying a cleaning liquid jet to the cleaning brush is further provided.
In a preferred aspect of the present invention, the cleaning brush further includes a cleaning brush moving mechanism that moves the cleaning brush between a cleaning position below the top ring and a standby position outside the top ring.
In a preferred aspect of the present invention, the cleaning brush is in contact with an inner peripheral surface of the retainer ring.
In a preferred aspect of the present invention, the cleaning brush is in contact with the lower surface of the retainer ring.
In a preferred aspect of the present invention, the cleaning brush is a first cleaning brush, and further includes a second cleaning brush that contacts a region inside the lower edge of the elastic film. And

  According to the present invention, the cleaning brush contacts the peripheral edge and the outer peripheral surface of the lower surface of the elastic film, and the polishing liquid (slurry) present in the gap between the elastic film and the retainer ring can be removed. Therefore, it is possible to prevent the solidified polishing liquid from accumulating in the gap between the elastic film and the retainer ring.

It is a figure showing a polish device concerning one embodiment of the present invention. It is sectional drawing which shows the top ring provided with the some airbag which can press the some area | region of a wafer independently. It is a figure which shows the top ring in a board | substrate conveyance position. It is a side view which shows a cleaning assembly. It is a top view which shows a cleaning assembly. It is an enlarged view which shows a cleaning brush and a part of top ring. FIG. 7A and FIG. 7B are schematic views showing the positional relationship between the cleaning assembly and the top ring. It is a figure which shows embodiment with which the washing | cleaning nozzle for supplying a washing | cleaning liquid to the clearance gap between a membrane and a retainer ring was provided. It is a side view which shows other embodiment of a cleaning assembly. FIG. 10 is a top view of the cleaning assembly shown in FIG. 9. It is a figure explaining a mode that the relative position of the cleaning brush with respect to a 2nd brush arm changes. It is a figure which shows embodiment provided with the tilt mechanism which inclines a cleaning brush with respect to a perpendicular direction. It is a side view which shows other embodiment of the cleaning assembly. It is a top view which shows other embodiment of the cleaning assembly. FIG. 15 is a side view of the cleaning assembly shown in FIG. 14. FIGS. 16A and 16B are schematic views showing the positional relationship between the cleaning assembly and the top ring. FIG. 16 is a side view showing an embodiment in which the second cleaning brush shown in FIGS. 14 and 15 is incorporated in the cleaning assembly shown in FIG. 9. FIG. 16 is a side view showing an embodiment in which the second cleaning brush shown in FIGS. 14 and 15 is incorporated in the cleaning assembly shown in FIG. 13.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing table 10 and a top ring (substrate holding unit) 1 that holds a substrate such as a wafer to be polished and presses the polishing pad 20 on the polishing table 10. I have.

  The polishing table 10 is connected to a motor (not shown) disposed below the table 10a via a table shaft 10a, and is rotatable around the table shaft 10a. A polishing pad 20 is affixed to the upper surface of the polishing table 10, and the surface 20 a of the polishing pad 20 constitutes a polishing surface for polishing the wafer W. A polishing liquid supply nozzle 62 is installed above the polishing table 10, and the polishing liquid (slurry) Q is supplied onto the polishing pad 20 on the polishing table 10 by the polishing liquid supply nozzle 62. .

  The top ring 1 is connected to the top ring shaft 65. The top ring shaft 65 is moved up and down with respect to the top ring head 64 by a vertical movement mechanism 81. By the vertical movement of the top ring shaft 65, the entire top ring 1 is moved up and down relative to the top ring head 64 for positioning. A rotary joint 82 is attached to the upper end of the top ring shaft 65.

  A vertical movement mechanism 81 that moves the top ring shaft 65 and the top ring 1 up and down includes a bridge 84 that rotatably supports the top ring shaft 65 via a bearing 83, a ball screw 88 attached to the bridge 84, and a column 86. And a servo motor 90 provided on the support base 85. A support base 85 that supports the servo motor 90 is fixed to the top ring head 64 via a support 86.

  The ball screw 88 includes a screw shaft 88a connected to the servo motor 90 and a nut 88b into which the screw shaft 88a is screwed. The top ring shaft 65 moves up and down integrally with the bridge 84. Therefore, when the servo motor 90 is driven, the bridge 84 moves up and down via the ball screw 88, and thereby the top ring shaft 65 and the top ring 1 move up and down.

  The top ring shaft 65 is connected to the rotary cylinder 66 through a key (not shown). The rotary cylinder 66 includes a timing pulley 67 on the outer peripheral portion thereof. A top ring rotation motor (top ring rotation device) 68 is fixed to the top ring head 64, and the timing pulley 67 is connected to a timing pulley 70 provided in the top ring rotation motor 68 via a timing belt 69. It is connected. Accordingly, when the top ring rotary motor 68 is rotationally driven, the rotary cylinder 66 and the top ring shaft 65 rotate together via the timing pulley 70, the timing belt 69, and the timing pulley 67, and the top ring 1 rotates. The top ring head 64 is supported by a top ring head shaft 80 that is rotatably supported by a frame (not shown). The polishing apparatus includes a control unit 50 that controls each device in the apparatus including the top ring rotation motor 68 and the servo motor 90.

  The top ring 1 is configured to hold the wafer W on the lower surface thereof. The top ring head 64 is configured to be pivotable about the top ring head shaft 80, and the top ring 1 holding the wafer W on the lower surface thereof receives the wafer W by receiving the rotation of the top ring head 64 (substrate transfer position). To a position above the polishing table 10.

  The polishing of the wafer W is performed as follows. The top ring 1 and the polishing table 10 are rotated, and the polishing liquid Q is supplied onto the polishing pad 20 from the polishing liquid supply nozzle 62 provided above the polishing table 10. In this state, the top ring 1 is lowered and the wafer W is pressed against the polishing surface 20 a of the polishing pad 20. The wafer W is brought into sliding contact with the polishing surface 20a of the polishing pad 20, whereby the surface of the wafer W is polished.

  FIG. 2 is a cross-sectional view showing the top ring 1 including a plurality of airbags that can independently press a plurality of regions of the wafer W. The top ring 1 includes a top ring body 41 connected to the top ring shaft 65 via a free joint 40 and a retainer ring 42 disposed below the top ring body 41.

  A flexible membrane (elastic film) 46 that contacts the wafer W and a chucking plate 47 that holds the membrane 46 are disposed below the top ring body 41. Between the membrane 46 and the chucking plate 47, four pressure chambers (airbags) C1, C2, C3, and C4 are provided. The pressure chambers C1, C2, C3, and C4 are formed by a membrane 46 and a chucking plate 47. The central pressure chamber C1 is circular, and the other pressure chambers C2, C3, C4 are circular. These pressure chambers C1, C2, C3 and C4 are arranged concentrically.

  Pressurized gas (pressurized fluid) such as pressurized air is supplied to the pressure chambers C1, C2, C3, and C4 by the pressure adjusting unit 100 through the fluid paths F1, F2, F3, and F4, respectively. Yes. The internal pressures of the pressure chambers C1, C2, C3, C4 can be changed independently of each other, so that the corresponding four regions of the wafer W, namely the central part, the inner intermediate part, the outer intermediate part, In addition, the polishing pressure for the peripheral edge can be adjusted independently.

  A pressure chamber C <b> 5 is formed between the chucking plate 47 and the top ring body 41. Pressurized gas is supplied to the pressure chamber C5 by the pressure adjusting unit 100 via the fluid path F5, or a negative pressure is formed in the pressure chamber C5. Thereby, the chucking plate 47 and the entire membrane 46 can move in the vertical direction. The peripheral end of the wafer W is surrounded by a retainer ring 42 so that the wafer W does not jump out of the top ring 1 during polishing. An opening is formed in a portion of the membrane 46 constituting the pressure chamber C3, and the wafer W is sucked and held on the top ring 1 by forming a vacuum in the pressure chamber C3. Further, the wafer W is released from the top ring 1 by supplying nitrogen gas, clean air, or the like to the pressure chamber C3.

  An annular rolling diaphragm 49 is disposed between the top ring main body 41 and the retainer ring 42, and a pressure chamber C <b> 6 is formed inside the rolling diaphragm 49. The pressure chamber C6 is connected to the pressure adjusting unit 100 via the fluid path F6. The pressure adjusting unit 100 supplies pressurized gas into the pressure chamber C <b> 6, thereby pressing the retainer ring 42 against the polishing pad 20.

  The pressurized gas from the pressure adjusting unit 100 is supplied into the pressure chambers C1 to C6 through the rotary joint 82 (see FIG. 1) and the fluid paths F1, F2, F3, F4, F5, and F6. Further, it is possible to form a negative pressure in the pressure chambers C1 to C6 by the pressure adjusting unit 100. Furthermore, the pressure chambers C1 to C6 are also connected to an atmosphere release valve (not shown), and the pressure chambers C1 to C6 can be opened to the atmosphere.

  The controller 50 determines a target value of the internal pressure of each pressure chamber C1, C2, C3, C4 based on the progress of polishing in the region of the wafer W corresponding to each pressure chamber C1, C2, C3, C4. . The control unit 50 sends a command signal to the pressure adjusting unit 100 to control the pressure adjusting unit 100 so that the internal pressures of the pressure chambers C1, C2, C3, and C4 coincide with the target value. Since the top ring 1 having a plurality of pressure chambers can independently press each region on the surface of the wafer W against the polishing pad 20 as the polishing progresses, the wafer W can be uniformly polished.

  FIG. 3 is a view showing the top ring 1 at the substrate transfer position on the side of the polishing table 10. The top ring 1 shown in FIG. 3 is in a state after passing the wafer to a substrate transfer device such as a pusher or a transfer robot (not shown). As shown in FIG. 3, a cleaning assembly 110 for cleaning the lower surface of the top ring 1 is provided at the substrate transfer position. The cleaning assembly 110 is fixed to a frame (not shown) of the polishing apparatus.

  FIG. 4 is a side view showing the cleaning assembly 110, and FIG. 5 is a top view of the cleaning assembly 110. The cleaning assembly 110 includes a cleaning brush 111 and a brush arm 114 that holds the cleaning brush 111. The cleaning brush 111 is composed of a number of bristles extending in the vertical direction and having the same length. These hairs are made of nylon, for example, and the diameter of each hair is 0.1 mm to 0.5 mm. The upper end of the cleaning brush 111 is disposed so as to contact the peripheral edge of the lower surface of the membrane (elastic film) 46 and the lower surface of the retainer ring 42. The lower end of the cleaning brush 111 is fixed to the brush arm 114.

  The tip (upper end) of the cleaning brush 111 forms a horizontal plane. The cleaning brush 111 shown in FIGS. 4 and 5 is divided into three bundles arranged along the radial direction of the top ring 1, but the present invention is not limited to this arrangement. For example, the cleaning brush 111 may be simply arranged along the radial direction of the top ring 1 without being divided into a plurality of bundles.

  The cleaning assembly 110 further includes a cleaning liquid supply nozzle 117 that supplies a cleaning liquid jet to the cleaning brush 111. The cleaning liquid supply nozzle 117 is held by a nozzle holder 118 fixed to the brush arm 114 and is disposed adjacent to the cleaning brush 111. The cleaning liquid supply nozzle 117 is inclined upward with respect to the horizontal direction and is disposed so as to apply a jet of cleaning liquid to the upper part of the cleaning brush 111. An example of the cleaning liquid used is pure water. The angle of the cleaning liquid supply nozzle 117 with respect to the horizontal direction and / or the vertical direction may be variable.

  The cleaning assembly 110 further includes a cleaning brush moving mechanism 120 that moves the cleaning brush 111 and the cleaning liquid supply nozzle 117. The cleaning brush moving mechanism 120 includes an air cylinder 121 as an actuator and a link 124 connected to a piston rod 121a of the air cylinder 121 via a joint 123. The brush arm 114 is rotatable about the pivot 126. When the piston rod 121a of the air cylinder 121 is moved, the brush arm 114 is rotated by a predetermined angle around the pivot 126, whereby the cleaning brush 111 and the cleaning liquid supply nozzle 117 fixed to the brush arm 114 are moved together. To do.

  FIG. 6 is an enlarged view showing a part of the cleaning brush 111 and the top ring 1. As shown in FIG. 6, a part of the cleaning brush 111 extends into the gap between the membrane 46 and the retainer ring 42 and contacts the outer peripheral surface of the membrane 46 and the inner peripheral surface of the retainer ring 42. Further, the cleaning brush 111 simultaneously contacts the peripheral edge of the lower surface of the membrane 46 and the inner peripheral edge of the lower surface of the retainer ring 42.

  FIGS. 7A and 7B are schematic views showing the positional relationship between the cleaning assembly 110 and the top ring 1 at the substrate transfer position. When the piston rod 121a of the air cylinder 121 is advanced, the brush arm 114 is rotated by a predetermined angle, whereby the cleaning brush 111 is moved to the cleaning position below the top ring 1 shown in FIG. When the piston rod 121a of the air cylinder 121 is retracted, the brush arm 114 rotates in the opposite direction, whereby the cleaning brush 111 is moved to the retracted position outside the top ring 1 shown in FIG.

  The cleaning of the top ring 1 by the cleaning assembly 110 is performed when the top ring 1 is at the substrate transfer position outside the polishing table 10. More specifically, the top ring 1 holding the wafer is moved to the substrate transfer position by the rotation of the top ring head shaft 80, and the wafer is transferred to the substrate transfer device (not shown) at this substrate transfer position. Next, the top ring 1 is rotated around its axis by a top ring rotating motor (top ring rotating device) 68. Further, the air cylinder 121 is driven and the cleaning brush 111 is moved to a cleaning position below the top ring 1 (see FIG. 7A). In this state, the cleaning liquid is sprayed from the cleaning liquid supply nozzle 117 toward the cleaning brush 111.

  As shown in FIG. 6, the cleaning brush 111 is in contact with the peripheral portion of the lower surface of the membrane 46, the outer peripheral surface of the membrane 46, the lower surface and the inner peripheral surface of the retainer ring 42 in the presence of the cleaning liquid, and the membrane 46 and the retainer ring. The polishing liquid (slurry) adhering to 42 is removed. A part of the cleaning brush 111 enters a gap between the membrane 46 forming the pressure chamber and the retainer ring 42 and removes the polishing liquid existing in the gap. By providing such a cleaning brush 111, it is possible to prevent the polishing liquid from being deposited and solidified, and to prevent subsequent wafers from being damaged. The polishing liquid adhering to the cleaning brush 111 is removed by the cleaning liquid.

  As shown in FIG. 8, a cleaning nozzle 128 may be provided for supplying a jet of cleaning liquid to the gap between the membrane 46 and the retainer ring 42 to wash away the polishing liquid (slurry). The cleaning nozzle 128 has a vertical portion 128b extending in the vertical direction, and an injection port 128c is formed at the tip thereof. The cleaning nozzle 128 is configured to be movable between a cleaning position (shown by a solid line) below the top ring 1 and a retreat position (shown by a dotted line) on the side of the top ring 1. When the cleaning nozzle 128 is in the cleaning position, the injection port 128 c is positioned below the gap between the membrane 46 and the retainer ring 42. In this position, the cleaning nozzle 128 removes the polishing liquid from the gap by supplying a jet of cleaning liquid to the gap between the membrane 46 and the retainer ring 42. Pure water can be used as the cleaning liquid.

  The cleaning nozzle 128 is provided separately from the cleaning assembly 110, and operates to clean the gap between the membrane 46 and the retainer ring 42 with a cleaning liquid before cleaning with the cleaning brush 111. Note that the cleaning liquid may be supplied to the gap between the membrane 46 and the retainer ring 42 from the cleaning nozzle 128 simultaneously with the cleaning by the cleaning brush 111.

  FIG. 9 is a side view showing another embodiment of the cleaning assembly 110, and FIG. 10 is a top view of the cleaning assembly 110 shown in FIG. In this embodiment, the brush arm 114 is divided into a first brush arm 114A and a second brush arm 114B, and the first brush arm 114A and the second brush arm 114B have the first screw 131 and The second screws 132 are fixed to each other. The cleaning brush 111 is held by the first brush arm 114 </ b> A, and the second brush arm 114 </ b> B is connected to the air cylinder 121 via the link 124.

  The first brush arm 114A is detachably fixed to the second brush arm 114B by a first screw 131 and a second screw 132. That is, by removing the first screw 131 and the second screw 132, the first brush arm 114A and the cleaning brush 111 held by the first brush arm 114A can be separated from the second brush arm 114B. Therefore, when the cleaning brush 111 is worn, the first brush arm 114A and the cleaning brush 111 can be easily replaced with new ones.

  An elongated hole 134 is formed in the first brush arm 114A, and the second screw 132 is screwed into the second brush arm 114B through the elongated hole 134. When the second screw 132 is loosened, the first brush arm 114 </ b> A can rotate in the horizontal direction within a certain angle range around the first screw 131. Therefore, as shown in FIG. 11, the cleaning brush 111 held by the first brush arm 114A can change its relative position to the second brush arm 114B.

  Although the cleaning brush 111 extends in the vertical direction, as shown in FIG. 12, a tilt mechanism that tilts the cleaning brush 111 within a certain angle range with respect to the vertical direction may be provided.

  FIG. 13 is a side view showing still another embodiment of the cleaning assembly 110. In this embodiment, the cleaning brush 111 extends obliquely toward the lower surface of the top ring 1. The upper end of the cleaning brush 111 forms a horizontal plane in the same manner as the previous embodiment. More specifically, the length of the hair constituting the cleaning brush 111 varies depending on the position, the length of the hair on the retainer ring side is short, and the length of the hair on the membrane side (elastic membrane side) is long. It has become.

  The cleaning liquid supply nozzle 117 is disposed so as to form a jet of the cleaning liquid horizontally and to apply the jet of the cleaning liquid to the upper end of the cleaning brush 111. In the present embodiment, the cleaning brush 111 is in contact with the peripheral edge and outer peripheral surface of the lower surface of the membrane 46 and the lower surface of the retainer ring 42, and can remove the polishing liquid from the gap between the membrane 46 and the retainer ring 42. .

  FIG. 14 is a top view showing still another embodiment of the cleaning assembly 110, and FIG. 15 is a side view of the cleaning assembly 110 shown in FIG. The configuration that is not particularly described is the same as the configuration of the embodiment illustrated in FIGS. 5 and 6, and thus redundant description is omitted. In this embodiment, the cleaning assembly 110 includes a cleaning brush 140 that contacts the lower surface of the membrane 46. Hereinafter, the cleaning brush 111 described above is referred to as a first cleaning brush 111, and the cleaning brush 140 is referred to as a second cleaning brush 140.

  The cleaning assembly 110 includes an extension arm 142 connected to the tip of the brush arm 114. The second cleaning brush 140 is held on the upper surface of the extension arm 142. The extension arm 142 is aligned with the brush arm 114.

  As shown in FIGS. 16A and 16B, the first cleaning brush 111 and the second cleaning brush 140 are moved together by the cleaning brush moving mechanism 120. More specifically, when the piston rod 121a of the air cylinder 121 is moved forward, the brush arm 114 and the extension arm 142 are rotated by a predetermined angle, whereby the first cleaning brush 111 and the second cleaning brush 140 are shown in FIG. It moves to the cleaning position below the top ring 1 shown in 16 (a). When the piston rod 121a of the air cylinder 121 is retracted, the brush arm 114 and the extension arm 142 are rotated in opposite directions, whereby the first cleaning brush 111 and the second cleaning brush 140 are moved to the top shown in FIG. It is moved to the retracted position outside the ring 1.

  In the cleaning position shown in FIG. 16 (a), the first cleaning brush 111 is in contact with the peripheral edge of the lower surface of the membrane 46, the outer peripheral surface of the membrane 46, the lower surface and the inner peripheral surface of the retainer ring 42, As shown in FIG. 14, the second cleaning brush 140 is in contact with a region on the lower surface of the membrane 46 that is inside the peripheral edge. Accordingly, the first cleaning brush 111 removes the polishing liquid (slurry) from the gap between the membrane 46 and the retainer ring 42, while the second cleaning brush 140 removes the polishing liquid (slurry) from the lower surface of the membrane 46. can do.

  The second cleaning brush 140 described above may be combined with other embodiments. FIG. 17 is a side view showing an embodiment in which the second cleaning brush 140 shown in FIGS. 14 and 15 is incorporated in the cleaning assembly 110 shown in FIG. The second brush arm 114B is designed to be longer than the second brush arm 114B shown in FIG. 9 and has an extension portion. The extension arm 142 is fixed to the extension portion of the second brush arm 114B. ing. The second cleaning brush 140 is held on the upper surface of the extension arm 142.

  18 is a side view showing an embodiment in which the second cleaning brush 140 shown in FIGS. 14 and 15 is incorporated in the cleaning assembly 110 shown in FIG. In this embodiment, the extension arm 142 is fixed to the tip of the brush arm 114. The second cleaning brush 140 is held on the upper surface of the extension arm 142.

  In the embodiment shown in FIGS. 14 to 18, the first cleaning brush 111 and the second cleaning brush 140 are moved together by the cleaning brush moving mechanism 120, but the second cleaning brush 140 is moved to the first cleaning brush 140. The cleaning brush moving mechanism (not shown) different from the cleaning brush moving mechanism 120 is installed at a location different from the brush 111 to move the second cleaning brush 140 between the cleaning position and the retracted position. May be.

  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 Top ring (substrate holder)
DESCRIPTION OF SYMBOLS 10 Polishing table 10a Table axis | shaft 20 Polishing pad 20a Polishing surface 40 Free joint 41 Top ring main body 42 Retainer ring 46 Membrane (elastic film)
47 Chucking plate 49 Rolling diaphragm 50 Control unit 62 Polishing liquid supply nozzle 65 Top ring shaft 66 Rotary cylinder 67 Timing pulley 68 Top ring rotation motor (top ring rotation device)
69 Timing belt 70 Timing pulley 80 Top ring head shaft 81 Vertical movement mechanism 82 Rotary joint 83 Bearing 84 Bridge 85 Support base 86 Post 88 Ball screw 88a Screw shaft 88b Nut 90 Servo motor 110 Cleaning assembly 111 Cleaning brush 114 Brush arm 114A First One brush arm 114B First brush arm 117 Cleaning liquid supply nozzle 118 Nozzle holder 120 Cleaning brush moving mechanism 121 Air cylinder 123 Joint 124 Link 126 Axis 128 Cleaning nozzle 131 First screw 132 Second screw 134 Elongated hole 140 Second Cleaning brush 142 Extension arm C1 to C6 Pressure chamber F1 to F6 Fluid path

Claims (6)

A polishing table for supporting the polishing pad;
An elastic film that forms a pressure chamber that presses the substrate against the polishing pad; and a top ring that is disposed around the elastic film and includes a retainer ring that presses the polishing pad;
A top ring rotating device for rotating the top ring about its axis;
A polishing apparatus comprising: a cleaning brush that contacts a peripheral portion and an outer peripheral surface of a lower surface of the elastic film.   The polishing apparatus according to claim 1, further comprising a cleaning liquid supply nozzle for supplying a cleaning liquid jet to the cleaning brush.   The polishing apparatus according to claim 1, further comprising a cleaning brush moving mechanism that moves the cleaning brush between a cleaning position below the top ring and a standby position outside the top ring. .   The polishing apparatus according to claim 1, wherein the cleaning brush contacts an inner peripheral surface of the retainer ring.   The polishing apparatus according to claim 1, wherein the cleaning brush contacts a lower surface of the retainer ring. The cleaning brush is a first cleaning brush;
The polishing apparatus according to claim 1, further comprising a second cleaning brush that is in contact with a region of the lower surface of the elastic film that is inside the peripheral edge.

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