Polishing device

Abstract

To provide a polishing device capable of detecting a polishing amount of a peripheral edge part of a substrate such as a wafer.SOLUTION: A polishing device comprises a sensor structure 100 for detecting a polishing amount of a peripheral edge part of a substrate W. The sensor structure 100 comprises: a sensor head 102 having a contact surface 102a; and a displacement sensor 101 for detecting the polishing amount of the peripheral edge part of the substrate W by means of displacement of the sensor head 102.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polishing apparatus. [Background technology]

[0002] During the semiconductor device manufacturing process, various films are formed on the peripheral edge of a wafer. These films can cause particles, so they need to be removed from the peripheral edge. Therefore, a polishing device equipped with an abrasive tool such as abrasive tape is used to polish the peripheral edge of the wafer and remove the films from the peripheral edge. This polishing device is configured to polish the peripheral edge by rotating the wafer around its axis while pressing the abrasive tool against the peripheral edge of the wafer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-13918 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the peripheral edge of a wafer is inclined and has a small area, it is generally difficult to accurately detect the amount of polishing at the peripheral edge of the wafer. Accurate detection of the amount of polishing is very important because it contributes to accurately determining the polishing endpoint of the wafer.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a polishing apparatus that can accurately detect the amount of polishing of the peripheral edge of a substrate such as a wafer. [Means for solving the problem]

[0006] In one aspect, a polishing apparatus is provided that includes a substrate stage that holds and rotates a substrate, a polishing head that presses a polishing tool against a peripheral edge of the substrate, and a sensor structure that detects the amount of polishing of the peripheral edge. The sensor structure includes a sensor head having a contact surface that contacts the peripheral edge, and a displacement sensor that detects the amount of polishing of the peripheral edge based on the displacement of the sensor head.

[0007] In one aspect, the polishing apparatus includes a control device that controls the operation of the polishing head and the sensor structure, and the control device causes the sensor structure to detect the amount of polishing of an area that is the same as the polishing target area of ​​the peripheral portion polished by the polishing head. In one aspect, the polishing apparatus is equipped with a sensor tilt mechanism that tilts the sensor structure, and the control device synchronizes the tilt angle of the sensor structure with the tilt angle of the polishing head by operating the sensor tilt mechanism, thereby bringing the contact surface into contact with the peripheral portion. In one aspect, the control device changes the tilt angle of the sensor structure by operating the sensor tilt mechanism to obtain a reference value in the rotation direction of the substrate, presses the sensor structure against the peripheral portion at the same tilt angle as the tilt angle of the polishing head, and determines the amount of displacement from the reference value as the amount of polishing performed by the polishing head.

[0008] In one aspect, the control device stores a target polishing amount for determining an end point of polishing of the substrate, and the control device terminates polishing of the peripheral portion when the determined polishing amount reaches the target polishing amount. In one embodiment, the control device stores a plurality of polishing angles for the peripheral portion, and when the polishing amount at one of the plurality of polishing angles reaches the target polishing amount, the control device changes the tilt angle of the sensor structure along with the tilt angle of the polishing head to obtain the polishing amount at another of the plurality of polishing angles.

[0009] In one aspect, the sensor structure includes a biasing member that biases the sensor head toward the peripheral edge portion, and a linear guide that restricts the movement direction of the sensor head to a linear direction. In one aspect, the contact surface has a width greater than the notch formed in the periphery. [Effects of the Invention]

[0010] The polishing apparatus is provided with a sensor structure for detecting the amount of polishing of the peripheral edge of the substrate, and therefore can accurately detect the amount of polishing of the peripheral edge of the substrate. [Brief explanation of the drawings]

[0011] [Figure 1] 1(a) and 1(b) are enlarged cross-sectional views showing the peripheral edge of the substrate. [Figure 2] FIG. 1 is a schematic diagram showing a polishing apparatus for polishing the peripheral portion of a wafer. [Figure 3] FIG. 2 is a diagram showing a head tilt mechanism for tilting the polishing head. [Figure 4] FIG. 2 is a diagram showing a polishing head (and a sensor structure) that is tilted up and down by a head tilt mechanism. [Figure 5] FIG. 2 is a diagram showing an enlarged view of the sensor structure. [Figure 6] FIG. 10 is a diagram showing a sensor tilt mechanism that tilts the sensor structure. [Figure 7] FIG. 10 is a flowchart showing a process for detecting the amount of polishing of the peripheral edge of a wafer. [Figure 8] FIG. 10 is a diagram showing an example of a polishing angle of a wafer. [Figure 9] FIG. 10 is a diagram showing changes in the reference value acquired while rotating the wafer. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1(a) and 1(b) are enlarged cross-sectional views showing the peripheral portion of a substrate. More specifically, FIG. 1(a) is a cross-sectional view of a so-called straight-type substrate, and FIG. 1(b) is a cross-sectional view of a so-called round-type substrate. An example of a substrate is a wafer. The peripheral portion of a substrate is defined as the region including the bevel portion, the top edge portion, and the bottom edge portion.

[0013] 1(a), the bevel portion is the outermost peripheral surface (indicated by the symbol S) of the wafer W, which is composed of an upper inclined portion (upper bevel portion) P, a lower inclined portion (lower bevel portion) Q, and a side portion (apex) R. In the wafer W of FIG. 1(b), the bevel portion is the portion (indicated by the symbol S) having a curved cross section that constitutes the outermost peripheral surface of the wafer W.

[0014] The top edge portion is an annular flat portion T1 located radially inward from the bevel portion S. The bottom edge portion is an annular flat portion T2 located opposite the top edge portion and radially inward from the bevel portion S. The top edge portion T1 and the bottom edge portion T2 are connected to the bevel portion S. The top edge portion T1 may include a region in which a device is formed.

[0015] 2 is a schematic diagram showing a polishing apparatus for polishing the peripheral edge of a wafer. This polishing apparatus includes a substrate stage 32 that holds and rotates a wafer W, which is an example of a substrate, and a polishing head 34 that presses a polishing tape 42 as a polishing tool against the peripheral edge of the wafer W held on the substrate stage 32.

[0016] The substrate stage 32 includes a substrate holding surface 37 that holds the wafer W by vacuum suction, and a stage motor 39 that rotates the substrate holding surface 37. The wafer W is placed on the substrate holding surface 37 by a transfer device (not shown) with its back surface facing downward. A groove 37a is formed in the substrate holding surface 37, and this groove 37a communicates with a vacuum line 40. The vacuum line 40 is connected to a vacuum source (e.g., a vacuum pump) (not shown).

[0017] When a vacuum is formed in the groove 37a of the substrate holding surface 37 via the vacuum line 40, the wafer W is held on the substrate holding surface 37 by vacuum suction. In this state, the stage motor 39 rotates the substrate holding surface 37, causing the wafer W to rotate around its axis. The diameter of the substrate holding surface 37 is smaller than the diameter of the wafer W, and the central region of the back surface of the wafer W is held by the substrate holding surface 37. The entire peripheral edge of the wafer W extends beyond the substrate holding surface 37.

[0018] The polishing head 34 is disposed adjacent to the substrate holding surface 37. More specifically, the polishing head 34 is disposed facing the peripheral edge of the wafer W on the substrate holding surface 37. The polishing head 34 includes a plurality of guide rollers 43 that support a polishing tape 42 as a polishing tool, a pressing member (e.g., a pressing pad) 44 that presses the polishing tape 42 against the peripheral edge of the wafer W, and an air cylinder 45 that serves as an actuator that applies a pressing force to the pressing member 44.

[0019] The air cylinder 45 is connected to the pressing member 44 and configured to move the pressing member 44 toward the substrate holding surface 37. The air cylinder 45 applies a pressing force to the pressing member 44, which causes the pressing member 44 to press the polishing tape 42 against the peripheral edge of the wafer W. Note that a grindstone may be used as the polishing tool instead of the polishing tape 42.

[0020] The polishing apparatus includes a head moving mechanism 60A that moves the polishing head 34 toward or away from the wafer W held on the substrate holding surface 37. The head moving mechanism 60A includes a connecting block 66A connected to the polishing head 34, and a linear actuator 67A that moves the polishing head 34 via the connecting block 66A. The linear actuator 67A is, for example, a combination of a ball screw mechanism and a servo motor (not shown), and is configured to move the polishing head 34 toward (or away from) a position where the wafer W is polished.

[0021] The polishing apparatus includes a tape feeding mechanism 50 incorporated in the polishing head 34. The tape feeding mechanism 50 is configured to feed the polishing tape 42. One end of the polishing tape 42 is connected to a supply reel 51, and the other end is connected to a take-up reel 52. The tape feeding mechanism 50 is configured to feed the polishing tape 42 from the supply reel 51 to the take-up reel 52 via the polishing head 34 at a predetermined speed. Examples of the polishing tape 42 that can be used include a tape with abrasive grains fixed to its surface, or a tape made of hard nonwoven fabric.

[0022] The polishing apparatus includes a pure water supply nozzle 57 disposed above the wafer W held on the substrate holding surface 37. The pure water supply nozzle 57 is configured to supply pure water to the wafer W. The pure water supply nozzle 57 is disposed above the center of the substrate holding surface 37. The pure water supplied to the upper surface of the rotating wafer W spreads over the entire upper surface of the wafer W due to centrifugal force, covering the entire upper surface of the wafer W. Therefore, the pure water can prevent particles from adhering to the upper surface of the wafer W during polishing of the peripheral portion of the wafer W.

[0023] As shown in FIG. 2, the polishing apparatus includes a sensor structure 100 that detects the amount of polishing of the peripheral edge of the wafer W. The sensor structure 100 includes a sensor head 102 having a contact surface 102a that contacts the peripheral edge of the wafer W, and a displacement sensor 101 that is connected to the sensor head 102 and detects the amount of polishing of the peripheral edge of the wafer W based on the displacement of the sensor head 102. Examples of the displacement sensor 101 include detectors such as a proximity sensor, a depth sensor, and a laser scale. The sensor head 102 is made of a high-hardness plate member (e.g., urethane rubber 90 degrees) coated with a coating that provides good sliding properties, or a high-hardness plate member to which a soft (e.g., resin) plate member that absorbs impacts caused by contact with the wafer is bonded.

[0024] The sensor structure 100 is configured to detect the amount of polishing of the peripheral edge of the wafer W polished by the polishing head 34 by bringing the sensor head 102 into contact with the peripheral edge of the wafer W. The detailed structure of the sensor structure 100 will be described later.

[0025] The polishing apparatus is equipped with a head moving mechanism 60B that moves the sensor structure 100 in a direction toward or away from the wafer W held on the substrate holding surface 37. The head moving mechanism 60B is equipped with a connecting block 66B connected to the sensor structure 100, and a linear actuator 67B that moves the sensor structure 100 via the connecting block 66B. The head moving mechanism 60B has a structure similar to that of the head moving mechanism 60A, and therefore a detailed description of the head moving mechanism 60B will be omitted.

[0026] 2, the polishing apparatus is equipped with a control device 80 that controls the operations of its components. The control device 80 is composed of a dedicated computer or a general-purpose computer. The control device 80 is equipped with a storage device 110 that stores a program, and a processing device 120 that executes calculations in accordance with the program.

[0027] 2, the control device 80 is electrically connected to the polishing head 34, the sensor structure 100, the head moving mechanisms 60A and 60B, and the stage motor 39, and is configured to control the operations of the polishing head 34, the sensor structure 100, the head moving mechanisms 60A and 60B, and the stage motor 39. The control device 80 may also control the operation of the pure water supply nozzle 57.

[0028] Fig. 3 is a diagram showing a head tilt mechanism that tilts the polishing head. Fig. 4 is a diagram showing the polishing head (and sensor structure) that tilts up and down by the head tilt mechanism. As shown in Fig. 3, the polishing apparatus is equipped with a head tilt mechanism 81 that tilts (pivots) the polishing head 34 with respect to the surface of the wafer W on the substrate stage 32. The head tilt mechanism 81 is equipped with a crank arm 55 that holds the polishing head 34 and a servo motor 56 connected to the crank arm 55.

[0029] One end of the crank arm 55 is fixed to the polishing head 34, and the other end of the crank arm 55 is connected to the servo motor 56. The crank arm 55 is generally parallel to the substrate holding surface 37. The control device 80 is electrically connected to the servo motor 56. When the servo motor 56 alternately rotates the crank arm 55 clockwise and counterclockwise by a predetermined angle in accordance with a command from the control device 80, the entire polishing head 34 tilts up and down relative to the surface of the wafer W (see the arrows in FIG. 4). In this way, the control device 80 can control the operation of the head tilt mechanism 81.

[0030] The peripheral edge of the wafer W is polished as follows. The wafer W held on the substrate holding surface 37 is rotated around its axis by the stage motor 39. Pure water is supplied from a liquid supply nozzle 57 to the upper surface of the rotating wafer W. The polishing head 34 tilts up and down while pressing the polishing tape 42 against the peripheral edge of the wafer W. In the presence of pure water, the polishing tape 42 comes into sliding contact with the peripheral edge of the rotating wafer W, thereby polishing the peripheral edge.

[0031] Fig. 5 is an enlarged view of the sensor structure. As shown in Fig. 5, the sensor structure 100 includes a displacement sensor 101, a sensor head 102, a biasing member 103 that biases the sensor head 102 toward the peripheral edge of the wafer W, a base plate 104 to which the displacement sensor 101 is fixed, and a linear guide 108 that restricts the movement direction of the sensor head 102 to a linear direction.

[0032] The biasing member 103 is fixed to the sensor head 102 and the base plate 104. In this embodiment, the biasing member 103 is a spring, but in another embodiment, it may be an air cylinder that biases the sensor head 102. The biasing member 103 presses the sensor head 102 against the peripheral edge of the wafer W with a biasing force that is such that the sensor head 102, which comes into contact with the peripheral edge of the rotating wafer W, does not bounce back with force and does not bend the wafer W more than necessary.

[0033] The linear guide 108 includes a guide rail 105 fixed to a base plate 104, and a slider 106 fixed to the sensor head 102 and attached to the guide rail 105. When the slider 106 moves along the guide rail 105, the sensor head 102 fixed to the slider 106 moves in a linear direction.

[0034] Fig. 6 is a diagram showing a sensor tilt mechanism that tilts the sensor structure. As shown in Fig. 6, the polishing apparatus is provided with a sensor tilt mechanism 151 that tilts (pivots) the sensor structure 100 with respect to the surface of the wafer W on the substrate stage 32. The sensor tilt mechanism 151 is provided with a crank arm 155 that holds the sensor structure 100, and a servo motor 156 connected to the crank arm 155.

[0035] One end of the crank arm 155 is fixed to the sensor structure 100, and the other end of the crank arm 155 is connected to a servo motor 156. The crank arm 155 is generally parallel to the substrate holding surface 37. The control device 80 is electrically connected to the servo motor 156. When the servo motor 156 alternately rotates the crank arm 155 clockwise and counterclockwise by a predetermined angle in accordance with a command from the control device 80, the entire sensor structure 100 tilts up and down relative to the surface of the wafer W (see the arrows in FIG. 4). In this way, the control device 80 can control the operation of the sensor tilt mechanism 151.

[0036] In this embodiment, head tilt mechanism 81 and sensor tilt mechanism 151 have the same structure, but in one embodiment, head tilt mechanism 81 and sensor tilt mechanism 151 may have different structures.

[0037] 6, the contact surface 102a of the sensor head 102 has a width greater than the notch Nt formed on the peripheral edge of the wafer W. Therefore, even if the sensor head 102 is pressed against the peripheral edge of the wafer W while the wafer W is rotating, the sensor head 102 will not enter the notch Nt, and damage to the notch Nt (and / or the sensor head 102) can be prevented.

[0038] Since a rotational force acts on the rotating wafer W, if the displacement sensor 101 is brought into direct contact with the peripheral edge of the wafer W, the displacement sensor 101 may be affected by the rotational force of the wafer W and may not be able to accurately detect the amount of polishing of the peripheral edge of the wafer W. In this embodiment, the sensor structure 100 has a structure that brings the sensor head 102 into contact with the peripheral edge of the wafer W, and therefore the displacement sensor 101 can accurately detect the amount of polishing of the peripheral edge of the wafer W via the sensor head 102.

[0039] Furthermore, by providing the sensor head 102, it is possible to prevent the displacement sensor 101 from directly contacting the peripheral edge of the wafer W. As a result, it is possible to prevent damage to the displacement sensor 101 due to contact with the notch Nt.

[0040] The control device 80 is configured to cause the sensor structure 100 to detect the amount of polishing in the same area (polishing amount detection area) as the area to be polished on the peripheral edge of the wafer W polished by the polishing head 34. The control device 80 is configured to synchronize the operations of the head tilt mechanism 81 and the sensor tilt mechanism 151. Therefore, the control device 80 synchronizes the tilt angle of the sensor structure 100 with the tilt angle of the polishing head 34 by operating the sensor tilt mechanism 151, and brings the contact surface 102a of the sensor head 102 into contact with the peripheral edge of the wafer W being polished.

[0041] With this configuration, the control device 80 can match the polishing amount detection area of ​​the sensor structure 100 with the polishing target area of ​​the polishing head 34, and as a result, the sensor structure 100 can detect in real time the polishing amount of the peripheral portion of the wafer W. The control device 80 controls the operations of the polishing head 34 and the sensor structure 100 based on the polishing amount sent from the sensor structure 100.

[0042] 7 is a flowchart showing a process for detecting the amount of polishing of the peripheral edge of a wafer. First, the control device 80 rotates the wafer W held on the substrate holding surface 37 of the substrate stage 32, and presses the sensor head 102 of the sensor structure 100 against the peripheral edge of the rotating wafer W (see step S101 in FIG. 7).

[0043] Thereafter, the control device 80 continuously changes the tilt angle of the sensor structure 100 while pressing the sensor head 102 against the peripheral edge of the wafer W, and acquires a reference value for each polishing angle of the wafer W (see step S102 in FIG. 7). By acquiring the reference value, the control device 80 stores the initial state of the peripheral edge of the wafer W.

[0044] 8 is a diagram showing an example of a polishing angle of a wafer. In the embodiment shown in FIG. 8, five polishing angles (polishing angle 1 to polishing angle 5) are set along the peripheral edge of the wafer W, and the memory device 110 of the control device 80 stores these five polishing angles. In one embodiment, at least one polishing angle may be set.

[0045] Fig. 9 is a diagram showing changes in the reference value acquired while rotating the wafer. In Fig. 9, the horizontal axis represents the rotation angle (0 to 360 degrees) of the wafer W, and the vertical axis represents the movement distance of the displacement sensor 101. As shown in Fig. 9, while rotating the wafer W, the control device 80 presses the sensor head 102 against the peripheral edge of the wafer W to acquire the reference value for each rotation angle of the wafer W.

[0046] By repeating this process, the reference values ​​for all polishing angles are obtained. For example, if five polishing angles are provided, the control device 80 obtains the reference values ​​for each rotation angle of the wafer W at polishing angles 1 to 5.

[0047] For example, the control device 80 operates the sensor tilt mechanism 151 to determine the tilt angle of the sensor structure 100 to be polishing angle 1 (see FIG. 8), and while pressing the sensor head 102 against the peripheral edge of the rotating wafer W, causes the displacement sensor 101 to detect the reference value of the peripheral edge of the wafer W at polishing angle 1.

[0048] Next, the control device 80 operates the sensor tilt mechanism 151 to determine the tilt angle of the sensor structure 100 to polishing angle 2 (see FIG. 8), and while pressing the sensor head 102 against the peripheral edge of the rotating wafer W, causes the displacement sensor 101 to detect the reference value of the peripheral edge of the wafer W at polishing angle 2. In this way, the control device 80 causes the displacement sensor 101 to detect the reference value of the peripheral edge of the wafer W at all of the polishing angles stored in the storage device 110.

[0049] 9, the movement distance of the displacement sensor 101 changes continuously, and the reference value for the rotation angle of the wafer W also changes continuously. In such a case, the control device 80 may average the continuously changing reference value.

[0050] 7, the control device 80 presses the sensor structure 100 against the peripheral edge of the wafer W at the same tilt angle as the tilt angle of the polishing head 34. At this time, the polishing head 34 continuously polishes the peripheral edge of the wafer W, and therefore the sensor head 102 is displaced toward the center of the wafer W by the biasing member 103.

[0051] The displacement sensor 101 detects the amount of displacement from the reference value. The amount of displacement detected by the displacement sensor 101 corresponds to the amount of polishing performed by the polishing head 34, and therefore the control device 80 determines the amount of displacement detected by the displacement sensor 101 as the amount of polishing performed by the polishing head 34.

[0052] 7, the control device 80 presses the sensor head 102 against the peripheral edge of the wafer W at the same tilt angle as the tilt angle of the polishing head 34, and determines (measures) the polishing amount in real time. The memory device 110 of the control device 80 stores a target polishing amount for determining the polishing end point of the wafer W. Therefore, when the determined polishing amount reaches the target polishing amount, the control device 80 changes the tilt angle of the sensor structure 100 along with the tilt angle of the polishing head 34, and changes the polishing angle to be polished from the polishing angle used for polishing (e.g., polishing angle 1) to a new polishing angle (e.g., polishing angle 2).

[0053] 7, when the polishing amounts at all polishing angles reach the target polishing amounts, the control device 80 ends polishing of the peripheral portion of the wafer W. In one embodiment, when one polishing angle is set, the control device 80 ends polishing of the peripheral portion of the wafer W when the determined polishing amounts reach the target polishing amount.

[0054] Because the peripheral edge of the wafer W is inclined and has a small area, it is generally difficult to accurately detect the amount of polishing of the peripheral edge of the wafer W for each polishing angle. According to this embodiment, the compact sensor structure 100 provided separately from the polishing head 34 can contact the peripheral edge of the wafer W at the same inclination angle as the inclination angle of the polishing head 34. Therefore, the sensor structure 100 can detect the amount of polishing of the peripheral edge of the wafer W during polishing in real time for each polishing angle.

[0055] The polishing head 34 starts polishing the peripheral edge of the wafer W from the moment it comes into contact with the peripheral edge of the wafer W. Therefore, even if a sensor (i.e., a sensor equivalent to the displacement sensor 101) is provided in the polishing head 34, the sensor cannot detect zero polishing amount (polishing amount at the start of polishing). As a result, the sensor may not be able to detect the desired polishing amount.

[0056] In this embodiment, the sensor structure 100 is provided separately from the polishing head 34, and therefore can contact the peripheral portion of the wafer W simultaneously with the polishing head 34. Therefore, the displacement sensor 101 can detect zero removal amount, and as a result, can reliably detect the desired removal amount.

[0057] The substrate stage 32 may hold the wafer W at an inclination due to installation errors. In this case, when the wafer W held on the substrate stage 32 rotates, the surface of the wafer W is inclined relative to the horizontal. In this state, even if the polishing head 34 is brought into contact with the peripheral edge of the wafer W, the polishing head 34 cannot stably polish the peripheral edge of the wafer W. Furthermore, if the center of the wafer W and the center of rotation of the substrate stage 32 are misaligned, the wafer W will rotate eccentrically, and the polishing head 34 will not stably polish the peripheral edge of the wafer W.

[0058] In this embodiment, the sensor structure 100 has a contact-type sensor structure in which the sensor head 102 is brought into contact with the peripheral edge of the wafer W. Therefore, the control device 80 can recognize the positional state of the wafer W during polishing (for example, the tilt of the wafer W, the eccentric rotation of the wafer W) based on the amount of displacement detected by the displacement sensor 101.

[0059] By bringing the sensor head 102 into contact (surface contact) with the peripheral edge of the wafer W, even when the wafer W is rotating at an angle relative to the horizontal direction, the sensor head 102 can continue to be in contact with the peripheral edge of the wafer W without moving away from the peripheral edge of the wafer W. As a result, the control device 80 can measure the amount of polishing while minimizing the effect of the positional state of the wafer W.

[0060] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims. [Explanation of symbols]

[0061] 32 Substrate stage 34 Polishing head 37 Board holding surface 37a groove 39 Stage Motor 40 Vacuum Line 42 Polishing tape 43 Guide roller 44 Pressing member 45 Air Cylinder 50 Tape feed mechanism 51 Unwinding reel 52 Take-up reel 55 crank arm 56 Servo motor 57 Pure water supply nozzle 60A, 60B Head movement mechanism 66A, 66B connecting block 67A, 67B Linear Actuator 80 Control device 81 Head tilt mechanism 100 Sensor structure 101 Displacement Sensor 102 Sensor head 102a Contact surface 103 biasing member 104 base plate 105 guide rail 106 Slider 108 Linear Guide 110 Storage device 120 Processing equipment 151 Sensor tilt mechanism 155 crank arm 156 Servo motor

Claims

1. A polishing apparatus comprising: a substrate stage that holds and rotates the substrate; a polishing head that presses a polishing tool against the peripheral edge of the substrate; a sensor structure for detecting the amount of polishing of the peripheral edge portion, The sensor structure includes: a sensor head having a contact surface that comes into contact with the peripheral edge portion; a displacement sensor that detects the amount of polishing of the peripheral edge portion based on the displacement of the sensor head, the polishing apparatus includes a control device that controls operations of the polishing head and the sensor structure; the control device causes the sensor structure to detect a polishing amount of an area that is the same as the polishing target area of the peripheral edge portion polished by the polishing head; the polishing apparatus includes a sensor tilt mechanism that tilts the sensor structure, The control device synchronizes the tilt angle of the sensor structure with the tilt angle of the polishing head by operating the sensor tilt mechanism, thereby bringing the contact surface into contact with the peripheral edge portion.

2. The control device The tilt angle of the sensor structure is changed by the operation of the sensor tilt mechanism, and a reference value in the rotation direction of the substrate is acquired; 2. The polishing apparatus according to claim 1, wherein the sensor structure is pressed against the peripheral portion at the same inclination angle as the inclination angle of the polishing head, and the amount of displacement from the reference value is determined as the amount of polishing performed by the polishing head.

3. the control device stores a target removal amount for determining a polishing end point of the substrate; 3. The polishing apparatus according to claim 2, wherein the control device terminates polishing of the peripheral portion when the determined polishing amount reaches the target polishing amount.

4. the control device stores a plurality of polishing angles for the peripheral edge portion; 4. The polishing apparatus according to claim 3, wherein when the polishing amount at one polishing angle among the plurality of polishing angles reaches the target polishing amount, the control device changes the tilt angle of the sensor structure along with the tilt angle of the polishing head to obtain the polishing amount at another polishing angle among the plurality of polishing angles.

5. The sensor structure includes: a biasing member that biases the sensor head toward the peripheral edge portion; 2. The polishing apparatus according to claim 1, further comprising a linear guide that restricts the movement direction of the sensor head to a linear direction.

6. 2. The polishing apparatus according to claim 1, wherein the contact surface has a width greater than the width of the notch formed in the peripheral edge portion.

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