Polishing apparatus and polishing method

Abstract

The invention provides a polishing device and a polishing method which can control the film thickness profile of a substrate with a simple structure and high precision. A polishing apparatus includes a stage that holds a substrate and has a non-rotating structure, a plurality of pressing actuators, a pad holder, and a polishing pad rotating mechanism.

Description

Technical Field

[0001] The present invention relates to a polishing device and a polishing method. Background Art

[0002] In recent semiconductor device manufacturing, the required precision for each process has reached the order of several nanometers, and chemical mechanical polishing (CMP) is no exception. In addition, with the increasing high integration, miniaturization, and multi-layerization of semiconductor integrated circuits, the trend is accelerating.

[0003] Therefore, in order to achieve such miniaturization and multi-layerization, as an issue, it is required to control the deviation of the film thickness after CMP within the order of several nanometers over the entire surface of the wafer in CMP.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-067609

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2021-112797

[0008] Technical Problems to be Solved by the Invention

[0009] Patent Document 1 discloses an upward-facing polishing device configured to perform local polishing of a wafer to control the film thickness profile of the wafer. The polishing device in Patent Document 1 is configured to polish the wafer by pressing a polishing pad against the wafer while rotating a worktable holding the wafer using a drive mechanism.

[0010] In order to precisely control the film thickness profile of the wafer, it is necessary to control the pressing force of the polishing pad for each small area on the wafer, and it is necessary to use a polishing pad with a small diameter. In this case, the polishing of the wafer takes time.

[0011] Patent Document 2 discloses an upward-facing polishing device having a plurality of piezoelectric elements disposed inside a polishing head that holds a wafer. In such a polishing device, similar to the polishing device in Patent Document 1, it is necessary to polish the wafer while rotating the polishing head holding the wafer.

[0012] In the structure of Patent Document 2, it is necessary to extend a plurality of power lines connected to the plurality of piezoelectric elements to the outside of the polishing head through a rotary connector. However, if all the plurality of power lines are connected to the rotary connector, the polishing device becomes complicated. Summary of the Invention

[0013] Therefore, an object of the present invention is to provide a polishing device and a polishing method capable of precisely controlling the film thickness profile of a substrate with a simple structure.

[0014] Technical means for solving technical problems

[0015] In one aspect, a grinding device is provided. The grinding device includes: a stage that holds the substrate with the surface to be ground of the substrate facing upward and has a non-rotating structure; a plurality of pressing actuators that are arranged inside the stage and independently press specific portions of the substrate; a pad holder that holds a grinding pad and presses the grinding pad against the surface to be ground; and a grinding pad rotation mechanism configured to rotate the grinding pad about the grinding pad itself.

[0016] In one aspect, the grinding device includes a grinding pad moving mechanism configured to move the grinding pad.

[0017] In one aspect, the grinding pad moving mechanism is configured to move the grinding pad along a spiral grinding track on the surface to be ground.

[0018] In one aspect, the grinding track has: a first track that extends from the peripheral portion of the substrate toward the central portion of the substrate; and a second track that extends from the central portion of the substrate toward the peripheral portion of the substrate and does not overlap with the first track.

[0019] In one aspect, the grinding device includes a film thickness measuring device that detects a film thickness signal corresponding to the film thickness of the substrate.

[0020] In one aspect, the grinding device includes a plurality of film thickness measuring devices including the film thickness measuring device arranged in a straight line, and the plurality of film thickness measuring devices are configured to detect a film thickness signal corresponding to the film thickness of the substrate along a linear measurement track on the surface to be ground.

[0021] In one aspect, the grinding device includes a grinding liquid supply device that includes a central supply nozzle for supplying grinding liquid from the central portion of the grinding pad.

[0022] In one aspect, the grinding device includes a grinding liquid supply device that includes a peripheral supply nozzle arranged around the grinding pad, and the peripheral supply nozzle is configured to supply grinding liquid to the upstream side of the grinding pad in the traveling direction of the grinding pad.

[0023] In one aspect, the grinding device includes a suction device that vacuum-sucks the substrate arranged on the stage, and the suction device includes a vacuum line arranged inside the stage.

[0024] In one mode, at least one of the plurality of pressing actuators is a cylinder having a hollow piston rod, and the vacuum line is connected to the piston rod.

[0025] In one mode, the polishing method uses a stage that houses a plurality of pressing actuators to hold the substrate with the polished surface of the substrate facing upward. While the pressing pressure of a specific pressing actuator among the plurality of pressing actuators is different from the pressing pressure of other pressing actuators, the polishing pad held by the pad holder is rotated about the polishing pad itself, and the polishing pad is pressed against the polished surface, and the substrate is polished in a non-rotating state.

[0026] In one mode, when polishing the substrate, the polishing pad is moved along a spiral polishing track on the polished surface.

[0027] In one mode, before polishing the substrate, the film thickness distribution of the substrate is measured, and based on the film thickness distribution, the pressing pressures of the plurality of pressing actuators are determined.

[0028] In one mode, when polishing the substrate, polishing liquid is supplied from a central supply nozzle disposed at the central portion of the polishing pad.

[0029] In one mode, when polishing the substrate, polishing liquid is supplied from a peripheral supply nozzle disposed around the polishing pad to the upstream side of the polishing pad in the traveling direction of the polishing pad.

[0030] Advantages of the Invention

[0031] The polishing apparatus can polish the polished surface of the wafer in a state where uneven shapes corresponding to specific portions of the wafer are formed on the placement surface of the stage by using a plurality of pressing actuators. Since the stage has a non-rotating structure, simplification of the control circuit of the pressing actuator can be achieved. Therefore, the polishing apparatus can accurately control the film thickness profile of the substrate with a simple structure. Description of the Drawings

[0032] Figure 1 is a perspective view showing an embodiment of the polishing apparatus.

[0033] Figure 2 is showing Figure 1 a cross-sectional view of the polishing apparatus shown.

[0034] Figure 3 (a) of Figure 3 and (b) of

[0035] Figure 4(a) and Figure 4 (b) of [Figure number] is a diagram showing a polishing pad moving along another example of a polishing track.

[0036] Figure 5 is a diagram showing a plurality of pressing actuators arranged in a grid pattern.

[0037] Figure 6 is a diagram showing a stage equipped with a pressing actuator.

[0038] Figure 7 is a diagram showing a film thickness measuring device moving along a spiral measurement track.

[0039] Figure 8 is a diagram showing a plurality of film thickness measuring devices arranged in a straight line.

[0040] Figure 9 is a diagram showing a film thickness measuring device mounted on a polishing pad.

[0041] Figure 10 is a diagram showing a central supply nozzle and peripheral supply nozzles.

[0042] Figure 11 is a diagram showing a central supply nozzle and peripheral supply nozzles connected to a polishing pad arm.

[0043] Figure 12 (a) of [Figure number] is a diagram showing a polishing liquid supply device having only a central supply nozzle, Figure 12 (b) of [Figure number] is a diagram showing a polishing liquid supply device having only peripheral supply nozzles, Figure 12 (c) of [Figure number] is a diagram showing a peripheral supply nozzle connected to a pad holder.

[0044] Figure 13 is a diagram showing the polishing process of a wafer by a polishing apparatus.

[0045] Figure 14 is a perspective view showing another embodiment of a polishing apparatus.

[0046] Figure 15 is a diagram showing another embodiment of a suction device.

[0047] Symbol Explanation

[0048] It should be noted that the "[Figure number]" in the translation is a placeholder that needs to be filled with the actual figure number in the original patent text.1. Stage, 1a Base, 1b Split Ring, 10 Press Actuator, 10a Pressing Surface, 20 Pad Holder, 21 Polishing Pad, 21a Polishing Surface, 22 Air Bag, 30 Polishing Pad Moving Mechanism, 31 Rotation Axis, 32 Polishing Pad Arm, 33 Rotation Axis, 34 Polishing Pad Drive Source, 40 Rotation Motor, 41, 42 Belt Pulley, 43 Belt, 50 Control Device, 50a Storage Device, 50b Arithmetic Device, 60 Control Circuit, 70 Moving Actuator, 80 Suction Device, 81 Vacuum Line, 81a Suction Port, 82 Vacuum Source, 83 Fixed Member, 90 Film Thickness Measuring Device, 100 Film Thickness Measuring Device Moving Mechanism, 101 Measuring Axis, 102 Measuring Arm, 103 Rotation Axis, 104 Film Thickness Measuring Device Drive Source, 130 Polishing Liquid Supply Device, 132 Central Supply Nozzle, 133 Peripheral Supply Nozzle, 150 Polishing Pad Rotation Mechanism, 155 Piston Rod, 155a Piston, 156 Cylinder Body, 160 Control Valve, 200 Support Column, 210 Support Rod, 220 Support Rod, 222 Moving Device, 232 Polishing Pad Arm, 240 Linear Actuator, 242 Moving Device, 302 Measuring Arm, W Wafer, Wa Ground Surface, Wb Back Surface, CL1, CL2 Central Axis, CP Center, PP Peripheral Portion, C1, C1' First Locus, C2, C2' Second Locus, PA Peripheral Portion Side Region, CA Center Side Region. Detailed Embodiment

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals and redundant descriptions are omitted. In the following embodiments, the structure of one embodiment without special description is the same as that of other embodiments, so redundant descriptions thereof are omitted.

[0050] Figure 1 It is a perspective view showing an embodiment of a polishing apparatus. Figure 2 It shows Figure 1 a cross-sectional view of the polishing apparatus shown. In Figure 1 and Figure 2 the embodiment shown, the polishing apparatus is a polishing apparatus that polishes the wafer W (an example of a substrate) serving as an object to be polished with the ground surface Wa facing upward. Such a polishing apparatus is called a face-up type polishing apparatus.

[0051] The polishing apparatus includes: a stage 1 that holds a wafer W with the polished surface Wa of the wafer W facing upward and has a non-rotating structure; a plurality of pressing actuators 10 that are disposed inside the stage 1 and independently press specific portions of the wafer W; a pad holder 20 that holds a polishing pad 21 that slidably contacts the polished surface Wa; a film thickness measuring device 90 that detects a film thickness signal corresponding to the film thickness of the wafer W; and a control device 50 that controls the operations of the components of the polishing apparatus.

[0052] The stage 1 is a non-rotating type substrate holding device configured to hold the wafer W and not rotate the held wafer W. More specifically, the non-rotating stage 1 is not connected to a rotating device such as a motor. When the wafer W is held on the stage 1, the center CP of the wafer W is located on the central axis CL1 of the stage 1.

[0053] The polishing pad 21 is made of, for example, a member such as a foamed polyurethane pad or a sponge, and has a size (diameter) smaller than the size (diameter) of the wafer W. The polishing pad 21 has a polishing surface 21a that presses against the polished surface Wa. The polishing surface 21a faces downward and faces the polished surface Wa.

[0054] The pad holder 20 is configured to press the polishing pad 21 against the polished surface Wa. More specifically, the pad holder 20 has an airbag 22 (see Figure 2 ) disposed inside thereof, and the polishing pad 21 is disposed below the airbag 22.

[0055] Therefore, by supplying compressed air from a compressed air source (not shown) to the airbag 22, the airbag 22 expands and presses the polishing pad 21 downward against the polished surface Wa. The polishing pad 21 polishes the polished surface Wa by pressing its polishing surface 21a against the polished surface Wa.

[0056] The polishing apparatus includes a polishing pad moving mechanism 30 configured to move the polishing pad 21. The polishing pad moving mechanism 30 has: a rotating shaft 31 that is connected to the pad holder 20; a polishing pad arm 32 that is connected to the rotating shaft 31; a rotating shaft 33 that is connected to the polishing pad arm 32; and a polishing pad drive source 34 that is connected to the rotating shaft 33.

[0057] The pad holder 20 is fixed to the lower end of the rotating shaft 31. As Figure 2 shown, the rotating shaft 31 is connected to a rotating motor 40 through pulleys 41, 42 and a belt 43 stretched between the pulleys 41, 42.

[0058] Therefore, the rotary electric machine 40 rotates the rotary shaft 31 through the pulleys 41 and 42 and the belt 43 by driving the rotary electric machine 40. The pad holder 20 fixed to the rotary shaft 31 and the polishing pad 21 held by the pad holder 20 rotate about the central axis CL2 of the rotary shaft 31.

[0059] These rotary electric machine 40, pulleys 41 and 42, and belt 43 constitute a polishing pad rotating mechanism 150 that rotates the polishing pad 21 together with the pad holder 20 about the central axis CL2.

[0060] The polishing pad drive source 34 is configured to move the polishing pad arm 32 in the X-axis direction and the Y-axis direction through the rotary shaft 33. The X-axis direction and the Y-axis direction are directions that extend parallel to the polished surface Wa of the wafer W held on the stage 1 and are orthogonal to each other.

[0061] The polishing pad drive source 34 moves the pad holder 20 and the polishing pad 21 in a direction parallel to the polished surface Wa (i.e., the X-axis direction and the Y-axis direction) through the rotary shaft 33 and the polishing pad arm 32 by driving the polishing pad drive source 34.

[0062] Although not shown, as an example of the polishing pad drive source 34, a combination of an X-axis actuator (for example, a combination of a ball screw extending in the X-axis direction and a servo motor) and a Y-axis actuator (for example, a combination of a ball screw extending in the Y-axis direction and a servo motor) can be cited.

[0063] The control device 50 includes a storage device 50a that stores a program and an arithmetic device 50b that executes arithmetic operations according to the commands included in the program. The storage device 50a includes a main storage device such as a RAM and an auxiliary storage device such as a hard disk drive (HDD) and a solid state drive (SSD). As an example of the arithmetic device 50b, a CPU (central processing unit) and a GPU (graphics processing unit) can be cited.

[0064] Figure 3 of (a) and Figure 3 of (b) are diagrams showing a polishing pad moving along an example of a polishing track. In Figure 3 of (a) and Figure 3 of (b) shown in the embodiment, the polishing pad 21 moves on the polished surface Wa along a spiral polishing track (refer to the dotted arrow) on the polished surface Wa to polish the polished surface Wa. The control device 50 is configured to move the polishing pad 21 along a specified polishing track (for example, Figure 3 of (a) and Figure 3 of (b) shown in the embodiment of the polishing track) stored in the storage device 50a by operating the polishing pad drive source 34.

[0065] As Figure 3in (a) and Figure 3 as shown in (b), the grinding track has a first track C1 extending from the peripheral portion PP of the wafer W toward the center CP of the wafer W and a second track C2 extending from the center CP of the wafer W toward the peripheral portion PP of the wafer W. Both the first track C1 and the second track C2 are grinding tracks that do not pass through the center CP of the wafer W but pass around the center CP.

[0066] Both the first track C1 and the second track C2 are formed so as not to overlap. Therefore, the polishing pad 21 is configured to uniformly polish the entire surface Wa to be polished in a manner of depicting different tracks.

[0067] The polishing pad moving mechanism 30 is configured to move the polishing pad 21 continuously along the first track C1 and the second track C2. Therefore, the polishing pad 21 moves from the peripheral portion PP of the wafer W toward the center CP of the wafer W along the first track C1 by the operation of the polishing pad driving source 34, and then moves from the center CP of the wafer W toward the peripheral portion PP of the wafer W along the second track C2.

[0068] In Figure 3 the embodiment shown in (a), the polishing pad 21 moves along a spiral grinding track (i.e., the first track C1 and the second track C2) that spirals in one direction (the first rotation direction). In Figure 3 the embodiment shown in (b), the polishing pad 21 moves along a spiral grinding track (i.e., the first track C1 and the second track C2) that spirals in the same rotation direction as the first rotation direction.

[0069] Figure 4 in (a) and Figure 4 in (b) are diagrams showing a polishing pad moving along other examples of the grinding track. In Figure 4 in (a) and Figure 4 in (b) of the embodiment shown, the polishing pad 21 also swings on the surface Wa to be polished along the spiral grinding track. The storage device 50a stores Figure 4 in (a) and Figure 4 the grinding track of the embodiment shown in (b).

[0070] The grinding track has a first track C1' extending from the peripheral portion PP of the wafer W toward the center CP of the wafer W and a second track C2' extending from the center CP of the wafer W toward the peripheral portion PP of the wafer W. Both the first track C1' and the second track C2' are grinding tracks that pass through the center CP of the wafer W.

[0071] In Figure 4 in (a) and Figure 4In (b), both the first locus C1' and the second locus C2' are formed so as not to overlap. Therefore, the polishing pad 21 is configured to uniformly polish the entire surface of the surface Wa to be polished while depicting different loci.

[0072] In Figure 4 In the embodiment shown in (a), the polishing pad 21 moves along a spiral first locus C1' that swirls around a first rotation direction, and after reaching the center CP of the wafer W, moves along a spiral second locus C2' that swirls around a second rotation direction opposite to the first rotation direction.

[0073] In Figure 4 In the embodiment shown in (b), the polishing pad 21 moves along a spiral first locus C1' that swirls around a second rotation direction, and after reaching the center CP of the wafer W, moves along a spiral second locus C2' that swirls around a first rotation direction.

[0074] As described above, the polishing pad 21 has a specific size. Therefore, the polishing pads 21 passing over the wafer W sometimes overlap unevenly. That is, assuming that the moving speed of the polishing pad 21 is constant, during the period when the polishing pad 21 moves from the peripheral portion PP of the wafer W to the center CP of the wafer W and then from the center CP to the peripheral portion PP once, the time that the polishing pad 21 stays at a specific point (any one point) on the wafer W is not necessarily uniform on the wafer W.

[0075] Therefore, the control device 50 can also control the polishing amount of the wafer W by changing the moving speed of the polishing pad 21 moving along the polishing locus based on the polishing conditions of the wafer W to be polished. Alternatively, the control device 50 can also control the polishing amount of the wafer W by changing the pressing force of the polishing pad 21 against the wafer W.

[0076] In this way, the control device 50 operates the polishing pad driving source 34 to move the polishing pad 21 along the spiral polishing locus, thereby enabling the entire surface of the wafer W to be polished uniformly.

[0077] In the present embodiment, the stage 1 is configured to hold the wafer W without rotating the wafer W. By moving the polishing pad 21 along the spiral polishing locus, an effect equivalent to that when polishing the wafer W in a state where the wafer W is rotated can be achieved.

[0078] Hereinafter, in this specification, the region on the surface Wa to be polished is divided into a peripheral portion side region PA including the peripheral portion PP of the wafer W and a center side region CA including the center CP of the wafer W (refer to Figure 3 of (a) and Figure 3 of (b), Figure 4 of (a) and Figure 4(b)). When the polishing pad 21 rotates at a constant rotational speed and the polishing pad 21 is moved along the polishing track, a difference may occur between the polishing amount in the peripheral region PA and the polishing amount in the central region CA. For example, in the central region CA, over-polishing may occur.

[0079] Therefore, in order to eliminate such a difference in the polishing amount, the polishing pad 21 may also move the peripheral region PA and the central region CA at different rotational speeds. For example, the rotational speed of the polishing pad 21 in the central region CA may be slower than the rotational speed of the polishing pad 21 in the peripheral region PA. In one embodiment, the polishing pad 21 may also move in the peripheral region PA and the central region CA in a non-rotating state.

[0080] In one embodiment, the moving speed of the polishing pad 21 may also be changed. For example, the moving speed of the polishing pad 21 in the peripheral region PA may be slower than the moving speed of the polishing pad 21 in the central region CA.

[0081] Figure 5 is a diagram showing a plurality of pressing actuators arranged in a grid pattern. In Figure 5 , the illustration of the stage 1 accommodating the plurality of pressing actuators 10 is omitted. As Figure 5 shown, the plurality of pressing actuators 10 are arranged in a grid pattern so as to fill the wafer W and are spread along the radial direction and the circumferential direction of the wafer W.

[0082] The plurality of pressing actuators 10 each have the same structure. The pressing actuator 10 is configured to be able to expand and contract. The control device 50 is configured to control the polishing amount at a specific part (or other parts except the specific part) of the wafer W by operating the pressing actuator 10. As an example of the pressing actuator 10, a piezoelectric element and a cylinder can be cited.

[0083] The pressing actuator 10 has a pressing surface 10a that can contact the back surface Wb on the side opposite to the polished surface Wa (refer to Figure 2 and Figure 5 ). The plurality of pressing surfaces 10a constitute the mounting surface of the stage 1. Therefore, when the wafer W is mounted on the mounting surface of the stage 1, the pressing surface 10a of the pressing actuator 10 faces the back surface Wb of the wafer W. The size of the pressing surface 10a is smaller than that of the polishing pad 21.

[0084] The plurality of pressing actuators 10 are configured to form an uneven shape corresponding to a specific part of the wafer W on the mounting surface of the stage 1 by the operation of the plurality of pressing actuators 10. When polishing the wafer W, the wafer W is mounted on the mounting surface formed by the plurality of pressing surfaces 10a.

[0085] When the pressing actuator 10 corresponding to a specific part of the wafer W is actuated, the pressing surface 10a pushes up the specific part of the wafer W. The specific part of the wafer W that is pushed up protrudes relative to other parts. In this state, when the polishing pad 21 is pressed against the surface Wa to be polished to polish the wafer W, the specific part of the wafer W is polished more actively than other parts. More specifically, the specific part of the wafer W that protrudes more than other parts is polished by the polishing pad 21 with a higher pressure than other parts. Therefore, the polishing amount of the specific part is greater than that of other parts.

[0086] In the case of reducing the polishing amount of the specific part of the wafer W, the pressing actuator 10 is used to make other parts except the specific part protrude. Alternatively, the pressing actuator 10 corresponding to the specific part of the wafer W is contracted. In this state, when the wafer W is polished, the specific part of the wafer W is polished by the polishing pad 21 with a lower pressure than other parts.

[0087] In one embodiment, as a method of avoiding polishing of the specific part of the wafer W, the pressure of the compressed air supplied to the airbag 22 of the polishing pad 21 may be set to 0, or the polishing pad 21 may be floated from the wafer W.

[0088] In this way, by actuating the pressing actuator 10 (and the polishing pad 21) corresponding to the specific part (and / or other parts) of the wafer W, the polishing amount at the specific part (and / or other parts) of the wafer W can be controlled.

[0089] Figure 6 It is a diagram showing a stage provided with a pressing actuator. As Figure 6 shown, the stage 1 includes a base 1a on which a plurality of pressing actuators 10 are placed and a plurality of split rings 1b arranged outside the base 1a in the radial direction. The base 1a has a flat plate shape extending parallel to the wafer W held on the stage 1. A plurality of pressing actuators 10 are spread over the base 1a.

[0090] The polishing apparatus includes control lines 60 respectively connected to the plurality of pressing actuators 10, and the plurality of pressing actuators 10 are electrically connected to the control device 50 through the plurality of control lines 60 extending inside the base 1a (refer to Figure 2 and Figure 6 ). The number of control lines 60 corresponds to the number of pressing actuators 10. The control device 50 is configured to control the operation of each pressing actuator 10 through each control line 60.

[0091] In the present embodiment, the stage 1 has a non-rotating structure, so there is no need to connect the control line 60 to a rotary connector. Therefore, simplification of the control line 60 can be achieved. Moreover, since there is no need to rotate the control line 60 together with the stage 1, disconnection of the control line 60 caused by entanglement of the control lines 60 with each other can be prevented.

[0092] A plurality of split rings 1b are arranged so as to surround the wafer W disposed on the mounting surface of the stage 1. The plurality of split rings 1b have the same structure. In the present embodiment, the stage 1 includes four split rings 1b (see Figure 1 ), and these split rings 1b have an annular shape surrounding the wafer W.

[0093] The plurality of split rings 1b are configured to approach and separate from each other. More specifically, the grinding apparatus includes a moving actuator 70 that moves each split ring 1b in the horizontal direction. As an example of the moving actuator 70, a combination of a cylinder, a ball screw, and a servo motor can be cited.

[0094] The moving actuator 70 is electrically connected to the control device 50. The control device 50 operates the moving actuator 70 to cause the plurality of split rings 1b to approach and separate from each other. When the wafer W is transported to the stage 1, the control device 50 operates the moving actuator 70 to cause the plurality of split rings 1b to separate from each other. In this state, the wafer W is placed on the mounting surface of the stage 1.

[0095] After that, the control device 50 operates the moving actuator 70 to cause the plurality of split rings 1b to approach each other. The plurality of split rings 1b that approach each other hold the wafer W. The plurality of split rings 1b prevent the wafer W from tilting during grinding of the wafer W. When holding the wafer W, the polished surface Wa of the wafer W and the upper surfaces of the plurality of split rings 1b are arranged in the same plane.

[0096] As Figure 6 shown, the grinding apparatus includes a suction device 80 that sucks the wafer W disposed on the stage 1. The suction device 80 includes a vacuum line 81 mounted on the stage 1 and a vacuum source 82 that sucks the wafer W through the vacuum line 81.

[0097] The vacuum line 81 is disposed inside the stage 1. More specifically, the vacuum line 81 penetrates the base 1a and is disposed in the central portion of the stage 1. The vacuum line 81 extends along the axis CL1 of the stage 1 and has a suction port 81a formed at the tip of the vacuum line 81. The suction port 81a opens upward and faces the back surface Wb of the wafer W.

[0098] The suction port 81a has a flange portion (flange shape) that extends outward. In one embodiment, the suction port 81a having a flange shape is made of an elastic body such as rubber so as to reliably adsorb the back surface Wb of the wafer W.

[0099] A plurality of pressing actuators 10 are arranged around the vacuum line 81. The suction device 80 includes a fixing member 83 to which the vacuum line 81 is attached. The fixing member 83 is configured to fix the relative positions of the vacuum line 81 and the pressing actuators 10 arranged around the vacuum line 81. The fixing member 83 to which the vacuum line 81 is attached is attached to the pressing actuators 10 around the vacuum line 81.

[0100] The vacuum source 82 is electrically connected to the control device 50, and the control device 50 is configured to control the operation of the vacuum source 82. The vacuum source 82 forms a vacuum on the back surface Wb side of the wafer W through the vacuum line 81 by the operation of the vacuum source 82. In this way, the suction device 80 performs vacuum suction on the wafer W through the suction port 81a of the vacuum line 81 to adsorb and hold the wafer W.

[0101] The polishing apparatus includes a film thickness measuring device 90 (see Figure 1 and Figure 2 ) that detects a film thickness signal corresponding to the film thickness of the wafer W (more specifically, the film formed on the polished surface Wa of the wafer W). As an example of the film thickness measuring device 90, an optical sensor and an eddy current sensor can be cited.

[0102] The polishing apparatus includes a film thickness measuring device moving mechanism 100 that moves the film thickness measuring device 90. The film thickness measuring device moving mechanism 100 includes: a measuring shaft 101 that is connected to the film thickness measuring device 90; a measuring arm 102 that is connected to the measuring shaft 101; a rotating shaft 103 that is connected to the measuring arm 102; and a film thickness measuring device drive source 104 that is coupled to the rotating shaft 103.

[0103] The film thickness measuring device drive source 104 is configured to move the measuring arm 102 in the X-axis direction and the Y-axis direction through the rotating shaft 103. The film thickness measuring device drive source 104 may have the same structure as the above-described polishing pad drive source 34 or may have a different structure.

[0104] Figure 7 It is a diagram showing the film thickness measuring device moving along a spiral measurement locus. In Figure 7 , for easy viewing of the drawing, only the film thickness measuring device 90 and the wafer W are depicted. As Figure 7 shown, the film thickness measuring device 90 is configured to detect a film thickness signal along a spiral measurement locus on the polished surface Wa of the wafer W.

[0105] The film thickness measuring device drive source 104 is electrically connected to the control device 50. Accordingly, the control device 50 operates the film thickness measuring device drive source 104 to move the film thickness measuring device 90 along a measurement locus on the surface Wa to be polished. The film thickness measuring device 90 moves from the peripheral portion PP of the wafer W toward the center CP of the wafer W along the measurement locus, thereby obtaining an overall film thickness signal of the surface Wa to be polished of the wafer W.

[0106] The film thickness measuring device 90 is electrically connected to the control device 50. Accordingly, the control device 50 measures the film thickness of the surface Wa to be polished based on the film thickness signal detected by the film thickness measuring device 90, and creates a film thickness profile (film thickness distribution data) of the wafer W.

[0107] In the present embodiment, the film thickness measuring device 90 is configured to detect an overall film thickness signal of the surface Wa to be polished by moving along a spiral measurement locus. Accordingly, the control device 50 can obtain an accurate film thickness distribution of the surface Wa to be polished.

[0108] Figure 8 is a diagram showing a plurality of film thickness measuring devices arranged in a line. As Figure 8 shown, the polishing apparatus may also include a plurality of film thickness measuring devices 90. These plurality of film thickness measuring devices 90 are arranged in a line in a direction parallel to the surface Wa to be polished, and are mounted on the measurement arm 102.

[0109] In Figure 8 the embodiment shown, the plurality of film thickness measuring devices 90 are configured to detect the film thickness signal of the wafer W along a linear measurement locus (refer to the black arrow in Figure 8 ) on the surface Wa to be polished. The film thickness measuring device moving mechanism 100 linearly moves the measurement arm 102 in the radial direction of the wafer W, whereby the plurality of film thickness measuring devices 90 detect the film thickness signal of the wafer W.

[0110] The film thickness measuring devices 90 arranged in a line have a length equal to or greater than the diameter of the wafer W. Accordingly, with a simple structure in which the measurement arm 102 is moved only once, the plurality of film thickness measuring devices 90 can detect the film thickness of the wafer W.

[0111] Figure 9 is a diagram showing a film thickness measuring device mounted on a polishing pad. As Figure 9 shown, the film thickness measuring device 90 does not necessarily need to be mounted on the measurement arm 102 via the measurement shaft 101, and may be mounted on the polishing pad arm 32.

[0112] In Figure 9In the illustrated embodiment, the film thickness measuring device 90 is disposed on the downstream side of the polishing pad 21 in the traveling direction of the polishing pad 21. With this configuration, the film thickness measuring device 90 can detect the film thickness of the polished surface Wa of the wafer W immediately after the polishing pad 21 has polished the polished surface Wa of the wafer W. The control device 50 can measure the film thickness of the polished surface Wa in real time by obtaining a film thickness signal from the film thickness measuring device 90 during the polishing of the wafer W.

[0113] The polishing apparatus includes a polishing liquid supply device 130 that supplies a polishing liquid containing abrasive grains such as silicon dioxide (SiO2) onto the polished surface Wa (see Figure 1 ). The polishing liquid supply device 130 includes a central supply nozzle 132 and a peripheral supply nozzle 133 for supplying the polishing liquid onto the polished surface Wa.

[0114] The control device 50 is configured to operate the central supply nozzle 132 and the peripheral supply nozzle 133 to supply the polishing liquid onto the polished surface Wa when polishing the wafer W. While supplying the polishing liquid onto the polished surface Wa, the control device 50 moves the polishing pad 21 along a polishing track. The polishing pad 21 polishes the polished surface Wa in a state where the polishing liquid is present on the polished surface Wa.

[0115] Figure 10 is a diagram showing the central supply nozzle and the peripheral supply nozzle. As Figure 10 shown, the central supply nozzle 132 is configured to supply the polishing liquid from the central portion of the polishing pad 21. The peripheral supply nozzle 133 is configured to supply the polishing liquid to the periphery of the polishing pad 21.

[0116] In Figure 1 the illustrated embodiment, the polishing liquid supply device 130 includes one central supply nozzle 132 and two peripheral supply nozzles 133. In Figure 10 the illustrated embodiment, the polishing liquid supply device 130 includes one central supply nozzle 132 and twelve peripheral supply nozzles 133.

[0117] Thus, the number of each of the central supply nozzle 132 and the peripheral supply nozzle 133 is not particularly limited. In one embodiment, the polishing liquid supply device 130 may include a plurality of central supply nozzles 132 and one peripheral supply nozzle 133. In the present embodiment, the plurality of peripheral supply nozzles 133 are arranged at equal intervals in the circumferential direction of the polishing pad 21.

[0118] Figure 11 is a diagram showing the central supply nozzle and the peripheral supply nozzle connected to the polishing pad arm. As Figure 11As shown, the central supply nozzle 132 passes through the rotating shaft 31 along the central axis CL2 and is connected to the polishing pad arm 32. The peripheral supply nozzle 133 is disposed outside the polishing pad 21 in the radial direction and is connected to the polishing pad arm 32.

[0119] Figure 12 (a) of Figure 12 is a diagram showing a polishing liquid supply device having only a central supply nozzle. Figure 12 (b) of Figure 12 is a diagram showing a polishing liquid supply device having only a peripheral supply nozzle. Figure 12 (c) of Figure 12 is a diagram showing a peripheral supply nozzle connected to the pad holder.

[0120] As Figure 12 As shown in (a) of Figure 12 , the polishing liquid supply device 130 may have a central supply nozzle 132 without having a peripheral supply nozzle 133. As Figure 12 As shown in (b) of Figure 12 , the polishing liquid supply device 130 may have a peripheral supply nozzle 133 without having a central supply nozzle 132. In this case, the peripheral supply nozzle 133 is also configured to supply the polishing liquid to the upstream side of the polishing pad 21 in the traveling direction of the pad holder 20.

[0121] In Figure 11 In the embodiment shown in Figure 11 , the peripheral supply nozzle 133 connected to the polishing pad arm 32 is configured not to rotate, but in one embodiment, the peripheral supply nozzle 133 may also be configured to rotate.

[0122] For example, as Figure 12 As shown in (c) of Figure 12 , the peripheral supply nozzle 133 may also be connected to the pad holder 20. With such a structure, the peripheral supply nozzle 133 can supply the polishing liquid to the periphery of the polishing pad 21 while rotating together with the pad holder 20. In one embodiment, the peripheral supply nozzle 133 may also be connected to the rotating shaft 31. According to such a structure, the peripheral supply nozzle 133 also rotates together with the rotating shaft 31.

[0123] Figure 13 is a diagram showing the polishing process of the polishing apparatus for the wafer. Before starting the polishing of the wafer W, the control device 50 measures the initial film thickness of the entire polished surface Wa of the wafer W and creates an initial film thickness profile (refer to step S101 and step S102). The created initial film thickness profile is stored in the storage device 50a.

[0124] The initial film thickness distribution can be created, for example, based on the film thickness signal detected by the film thickness measuring device 90. In this case, the wafer W is held on the stage 1 with the polished surface Wa of the wafer W facing upward, and in this state, the film thickness measuring device 90 acquires the film thickness signal of the polished surface Wa along the measurement locus on the polished surface Wa. When holding the wafer W, the control device 50 operates the moving actuator 70 to open the split ring 1b of the stage 1, and when the wafer W is placed on the plurality of pressing actuators 10, the split ring 1b is closed.

[0125] In one embodiment, the control device 50 can also create the initial film thickness distribution based on the film thickness measurement value obtained by an independent film thickness measuring device (not shown). In this case, the initial film thickness distribution is also stored in the storage device 50a.

[0126] After that, the control device 50 compares the initial film thickness profile with the target film thickness profile and creates the distribution of the target polishing amount on the polished surface Wa. The control device 50 determines the portions (specific portions) to be polished positively (and / or negatively) based on the created distribution of the target polishing amount.

[0127] In this way, the control device 50 determines the pressing force or the pressing pressure of the pressing actuator 10 corresponding to the specific portion and / or other portions other than the specific portion of the wafer W based on the initial film thickness profile. More specifically, the control device 50 determines the pressing force or the pressing pressure required to achieve the target polishing amount within a specified polishing time based on the created distribution of the target polishing amount.

[0128] The pressing force of the pressing actuator 10 can also be adjusted (corrected) according to the hardness of the polishing pad 21. For example, when polishing the wafer W using a relatively hard polishing pad 21, even if the pressing force of the pressing actuator 10 is small, the pressing force applied to the polished surface Wa by the polishing pad 21 changes significantly.

[0129] On the other hand, for example, when polishing the wafer W using a relatively soft polishing pad 21, the reaction force received by the wafer W from the pressing surface 10a of the pressing actuator 10 is absorbed by the polishing pad 21. Therefore, when the magnitude of the pressing force of the pressing actuator 10 is the same as the above-mentioned pressing force, the pressing force applied to the polished surface Wa by the polishing pad 21 does not change significantly.

[0130] In this way, the control device 50 can also correct the pressing force of the pressing actuator 10 according to the hardness of the polishing pad 21. The hardness data indicating the hardness of the polishing pad 21 is stored in the storage device 50a.

[0131] After the control device 50 determines the pressing force (or pressing pressure) required to achieve the target grinding amount, it operates the pressing actuator 10 based on the determined pressing force (refer to step S103). After that, the control device 50 starts grinding the ground surface Wa of the wafer W in a state where the pressing pressure (or pressing force) of a specific pressing actuator 10 among the plurality of pressing actuators 10 is different from the pressing pressure (or pressing force) of the other pressing actuators 10 (refer to step S104). The control device 50 may also start grinding the ground surface Wa of the wafer W without operating the pressing actuators 10 other than the pressing actuator 10 corresponding to a specific part of the wafer W.

[0132] At this time, the control device 50 operates the polishing liquid supply device 130 to supply the polishing liquid onto the ground surface Wa from at least one of the central supply nozzle 132 and the peripheral supply nozzle 133.

[0133] In the present embodiment, the stage 1 has a non-rotating structure. Therefore, when grinding the wafer W, it is possible to prevent the wafer W from shifting in the circumferential direction due to the rotation of the wafer W. As a result, the positional relationship between a specific part (and / or other parts) of the wafer W and the part of the wafer W where the pressing force acts does not shift. Therefore, the control device 50 can grind the wafer W with high precision using the polishing pad 21.

[0134] When grinding the wafer W, the control device 50 rotates the polishing pad 21 about the central axis CL2, and in a state where the polishing liquid is supplied from the polishing liquid supply device 130, moves the polishing pad 21 along a spiral grinding track on the ground surface Wa.

[0135] When grinding the wafer W, the control device 50 does not necessarily need to move the polishing pad 21 along a spiral grinding track according to a specific part (and / or other parts) of the wafer W. For example, when the part to be ground on the ground surface Wa exists locally, the control device 50 may also directly move the polishing pad 21 to the local part and make the polishing pad 21 slide in contact with the local part.

[0136] The stage 1 is configured such that when holding the wafer W, the ground surface Wa of the wafer W and the upper surfaces of the plurality of split rings 1b are arranged in the same plane. Therefore, the polishing pad 21 can grind the peripheral portion PP of the wafer W without being obstructed by the stage 1. When locally grinding the peripheral portion PP of the wafer W, the control device 50 operates the pressing actuator 10 corresponding to the peripheral portion PP to apply a pressing force to the peripheral portion PP, whereby the polishing pad 21 can be actively pressed against the peripheral portion PP.

[0137] In the polishing of the wafer W, the control device 50 can also use the film thickness measuring device 90 to measure the film thickness of the wafer W. The control device 50 determines whether the film thickness of the wafer W has reached a specified target film thickness (i.e., whether the polishing end point has been reached) (refer to step S105). For example, the control device 50 determines the polishing end point when the difference between the thickest part and the thinnest part of the film thickness of the wafer W reaches within a specified range.

[0138] When the film thickness of the wafer W has not reached the target film thickness (refer to "No" in step S105), the control device 50 continues to polish the wafer W. On the other hand, when the film thickness of the wafer W has reached the target film thickness (refer to "Yes" in step S105), the control device 50 ends the polishing of the wafer W (refer to step S106).

[0139] In one embodiment, the control device 50 can also end the polishing of the wafer W based on a specified polishing time instead of determining the polishing end point based on the measurement of the film thickness of the wafer W. For example, the control device 50 can measure the film thickness distribution of the wafer W again after polishing the wafer W for a specified polishing time, and end the polishing of the wafer W when the film thickness distribution of the wafer W becomes a desired film thickness distribution.

[0140] Figure 14 is a perspective view showing another embodiment of the polishing apparatus. In Figure 14 the embodiment shown, the structures not specifically described are the same as those of the above embodiment, so the repeated description thereof is omitted.

[0141] In Figure 14 the embodiment shown, the polishing apparatus also has structures corresponding to the polishing liquid supply device 130 and the polishing pad rotation mechanism 150, but the illustrations of these polishing liquid supply device 130 and polishing pad rotation mechanism 150 are omitted.

[0142] As Figure 14 shown, the polishing pad moving mechanism 30 includes a polishing pad arm 232 connected to the rotation shaft 31 and a plurality of support rods 210 that support the polishing pad arm 232 so as to be movable.

[0143] The polishing apparatus includes a plurality of support columns 200 disposed around the stage 1. The support columns 200 extend in the Z-axis direction. The Z-axis direction is a direction that extends perpendicular to the polished surface Wa of the wafer W held on the stage 1, in other words, a direction that extends perpendicular to the X-axis direction and the Y-axis direction. The support rods 210 are installed between adjacent support columns 200 and extend in the X-axis direction.

[0144] The polishing pad moving mechanism 30 includes: a moving device 242 that moves the polishing pad arm 232 along the support rod 210 in the X-axis direction; and a linear actuator 240 that moves the polishing pad 21 (and the pad holding body 20) together with the rotating shaft 31 in the Y-axis direction.

[0145] The moving device 242 is, for example, a servo motor connected to the support rod 210. In this case, the moving device 242 moves the polishing pad 21 (as well as the rotating shaft 31 and the pad holding body 20) together with the polishing pad arm 232 in the X-axis direction through the action of the moving device 242 via the support rod 210.

[0146] The linear actuator 240 is, for example, a combination of a moving body connected to the rotating shaft 31 and a guide rail for moving the moving body in the Y-axis direction. In this case, the linear actuator 240 moves the polishing pad 21 (as well as the rotating shaft 31 and the pad holding body 20) together with the moving body in the Y-axis direction through the action of the linear actuator 240.

[0147] The control device 50 is electrically connected to these moving device 242 and linear actuator 240. Therefore, the control device 50 can move the polishing pad 21 (and the pad holding body 20) freely in the X-axis direction and the Y-axis direction by operating the moving device 242 and the linear actuator 240 respectively.

[0148] The film thickness measuring device moving mechanism 100 includes: a measuring arm 302 on which a plurality of film thickness measuring devices 90 arranged in a straight line are mounted; and a support rod 220 that supports the measuring arm 302 so as to be movable.

[0149] The support rod 220 is installed between adjacent columns 200 and extends in the Y-axis direction. In Figure 14 the illustrated embodiment, the support rod 210 and the support rod 220 extend in mutually orthogonal directions (i.e., the X-axis direction and the Y-axis direction).

[0150] The film thickness measuring device moving mechanism 100 includes a moving device 222 that moves the measuring arm 302 along the support rod 220 in the Y-axis direction. The moving device 222 is, for example, a servo motor and may have the same structure as the moving device 242. In this case, the moving device 222 moves the plurality of film thickness measuring devices 90 together with the measuring arm 302 in the Y-axis direction through the action of the moving device 222 via the support rod 220.

[0151] The control device 50 is electrically connected to the moving device 222. Therefore, the control device 50 can move the measuring arm 302 on which the plurality of film thickness measuring devices 90 are mounted freely in the Y-axis direction by operating the moving device 222.

[0152] Figure 15 FIG. is a diagram showing other embodiments of the attracting device. In Figure 15 , in order to easily observe the drawings, a single pressing actuator 10 is depicted. As Figure 15 shown, the pressing actuator 10 is a cylinder having a hollow piston rod 155, a cylinder main body 156 that houses the piston rod 155, and a piston 155a that is connected to the piston rod 155 and divides the interior of the cylinder main body 156.

[0153] In Figure 15 , illustration of the air supply / discharge lines connected to the upper and lower spaces of the piston 155a is omitted. The control device 50 controls the pressure of the fluid flowing in the air supply / discharge lines to control the pressing pressure of the pressing actuator 10 on the wafer W.

[0154] The tip of the hollow piston rod 155 serves as a suction port for sucking the back surface Wb (i.e., the lower surface) of the wafer W. The suction port is the same as Figure 6 . Similarly, it preferably has a flange portion (not shown) that expands outward. The flange portion is made of an elastic body such as rubber so that the back surface Wb of the wafer W can be reliably adsorbed.

[0155] In Figure 15 the embodiment shown, the pressing actuator 10 and the vacuum line 81 can be integrally formed. Therefore, there is no need to separately arrange the vacuum line 81 from the pressing actuator 10, and the grinding device can achieve space saving of the stage 1.

[0156] In Figure 15 , a single vacuum line 81 is arranged relative to the single pressing actuator 10. The attracting device 80 may also have a number of vacuum lines 81 corresponding to the number of pressing actuators 10. In one embodiment, the attracting device 80 may also have a number of vacuum lines 81 that is less than the number of pressing actuators 10.

[0157] In Figure 6 the embodiment shown, the attracting device 80 includes a vacuum line 81 arranged at the central portion of the stage 1. However, in one embodiment, the attracting device 80 may also include a plurality of vacuum lines 81 uniformly arranged on the entire mounting surface of the stage 1. With such an arrangement, it is possible to prevent the adsorption pressure from acting locally on the wafer W and to make the adsorption pressure act uniformly on the entire surface of the wafer W. In one embodiment, the embodiments shown in Figure 6 and Figure 15 may also be combined.

[0158] In Figure 15 the embodiment shown, the attracting device 80 includes a control valve 160 instead of including a vacuum source 82 (see Figure 6) Thus, the attracting device 80 does not necessarily need to be provided with a vacuum source 82. For example, the vacuum line 81 may also be connected to a common line (not shown) for forming a vacuum laid in the factory.

[0159] In this case, the control device 50 operates the control valve 160 installed in the vacuum line 81, thereby forming a vacuum on the back surface Wb side of the wafer W. Similarly, Figure 6 in the illustrated embodiment, the attracting device 80 may also be provided with a control valve 160 instead of the vacuum source 82.

[0160] The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to implement the present invention. Various modifications of the above-described embodiments can be naturally achieved by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments and can be interpreted as covering the broadest scope in accordance with the technical idea defined by the claims.

Claims

1. A grinding device, characterized in that: The grinding device comprises: a stage that holds the substrate with the polished surface of the substrate facing upward and has a non-rotating structure; a plurality of pressing actuators, which are arranged inside the stage and independently press specific locations of the substrate; a pad holder that holds a polishing pad and presses the polishing pad against the polished surface; and A polishing pad rotating mechanism is configured to rotate the polishing pad about the polishing pad itself.

2. The grinding device according to claim 1, wherein: The polishing device includes a polishing pad moving mechanism configured to move the polishing pad.

3. The grinding device according to claim 2, wherein: The polishing pad moving mechanism is configured to move the polishing pad along a spiral polishing trajectory on the polished surface.

4. The grinding device according to claim 3, wherein: The grinding track has: a first track extending from a peripheral portion of the substrate toward a central portion of the substrate; as well as A second track extends from a central portion of the substrate toward a peripheral portion of the substrate and does not overlap with the first track.

5. The grinding device according to claim 1, wherein: The polishing device includes a film thickness measuring device that detects a film thickness signal corresponding to a film thickness of the substrate.

6. The grinding device according to claim 5, wherein: The polishing device includes a plurality of film thickness measuring devices including the film thickness measuring device arranged in a straight line, The plurality of film thickness measuring devices are configured to detect a film thickness signal corresponding to the film thickness of the substrate along a linear measurement trajectory on the polished surface.

7. The grinding device according to claim 1, wherein: The polishing device includes a polishing liquid supply device including a central supply nozzle for supplying the polishing liquid from a central portion of the polishing pad.

8. The grinding device according to claim 1, wherein: The polishing device includes a polishing liquid supply device including a peripheral supply nozzle arranged around the polishing pad. The peripheral supply nozzle is configured to supply the polishing liquid toward the upstream side of the polishing pad in the traveling direction of the polishing pad.

9. The grinding device according to claim 1, wherein: The polishing device includes a suction device that performs vacuum suction on the substrate disposed on the stage. The suction device includes a vacuum line disposed inside the stage.

10. The grinding device according to claim 9, wherein: At least one of the plurality of pressing actuators is a cylinder having a hollow piston rod. The vacuum line is connected to the piston rod.

11. A grinding method, characterized in that: The polishing method uses a stage that accommodates a plurality of pressing actuators to hold the substrate with the polished surface of the substrate facing upward. While the pressing pressure of a specific pressing actuator among the multiple pressing actuators is made different from the pressing pressures of the other pressing actuators, the polishing pad held by the pad holder is rotated around the polishing pad itself and the polishing pad is pressed against the polished surface to polish the substrate in a non-rotating state.

12. The grinding method according to claim 11, wherein: When polishing the substrate, the polishing pad is moved along a spiral polishing track on the polished surface.

13. The grinding method according to claim 11, wherein: Before grinding the substrate, measuring the film thickness distribution of the substrate, Based on the film thickness distribution, the pressing pressures of the plurality of pressing actuators are determined.

14. The grinding method according to claim 11, wherein: When the substrate is polished, polishing liquid is supplied from a central supply nozzle disposed at a central portion of the polishing pad.

15. The grinding method according to claim 11, wherein: When polishing the substrate, polishing liquid is supplied from peripheral supply nozzles arranged around the polishing pad toward an upstream side of the polishing pad in a traveling direction of the polishing pad.

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