Thickness measurement unit position setting method and grinding device

Abstract

Provided is a method for setting the location of a thickness measuring part for measuring the thickness of a substrate using measuring light in a grinding device for grinding the substrate. The method includes: holding a calibration substrate by a substrate holding part; irradiating the calibration substrate with the measuring light from the thickness measuring part while moving the thickness measuring part closer to or away from the calibration substrate; acquiring the intensity of reflected light of the measuring light reflected from the calibration substrate; and setting the location of the thickness measuring part at which the acquired intensity of the reflected light becomes an optimal value as a thickness measurement location for the substrate.

Description

Method for setting position of substrate thickness measurement unit and grinding device

[0001] The present disclosure relates to a method for setting the position of a substrate thickness measuring unit and a grinding apparatus.

[0002] Patent Document 1 discloses a method for self-grinding a substrate holding means in a processing device, in which the upper surface of the substrate holding means is ground using a grinding wheel to improve the parallelism between the grinding portion and the upper surface of the substrate holding means.

[0003] Japanese Patent Application Laid-Open No. 2021-137883

[0004] The technology according to the present disclosure sets the position of a thickness measuring unit that measures the thickness of a substrate using measurement light to an appropriate position in a grinding apparatus that grinds a substrate.

[0005] One aspect of the present disclosure is a method for setting the position of a thickness measurement unit for measuring the thickness of a substrate using measurement light in a grinding apparatus that grinds a substrate, the method including: holding a calibration substrate with a substrate holder; irradiating the calibration substrate with the measurement light from the thickness measurement unit while moving the thickness measurement unit toward or away from the calibration substrate; acquiring the intensity of the reflected light of the measurement light reflected by the calibration substrate; and setting the position of the thickness measurement unit at which the acquired intensity of the reflected light is optimal as a thickness measurement position of the substrate. Note that in the present disclosure, grinding also includes polishing.

[0006] According to the present disclosure, in a grinding apparatus that grinds a substrate, the position of a thickness measuring unit that measures the thickness of the substrate using measurement light can be set to an appropriate position.

[0007] FIG. 1 is a plan view showing an outline of the configuration of a grinding device according to this embodiment. FIG. 2 is a side view showing the configuration of a grinding unit and a chuck. FIG. 3 is a side view showing an outline of the configuration of a thickness measurement unit. FIG. 4 is an explanatory diagram showing an example of an operation screen displayed on a display panel. FIG. 5 is a flow chart showing a method for automatically setting the Z-axis of a sensor after performing self-grinding of a chuck. FIG. 6 is an explanatory diagram showing the state in which automatic Z-axis setting of a sensor is performed. FIG. 7 is an explanatory diagram showing the relationship between the Z-axis position of a sensor and the intensity of reflected light. FIG. 8 is an explanatory diagram showing the state in which Z-axis setting of a sensor is performed using a block gauge. FIG. 9 is an explanatory diagram showing the state in which a sensor is moved during grinding after automatic Z-axis setting of a sensor is performed. FIG. 10 is an explanatory diagram showing the state in which a radial position of a sensor is set.

[0008] In the semiconductor manufacturing process, the back surface of a semiconductor substrate (hereinafter referred to as a wafer) is ground to thin the wafer. Grinding of the back surface of the wafer is performed, for example, by rotating a chuck while holding the front surface of the wafer, and bringing a grinding wheel of a grinding unit into contact with the back surface of the wafer.

[0009] Here, grinding debris generated during the wafer grinding process may accumulate on the upper surface of the chuck, which may reduce the parallelism between the grinding wheel of the grinding unit and the upper surface of the chuck. Therefore, the upper surface of the chuck may be ground by the grinding unit to improve the parallelism between the lower surface of the grinding wheel of the grinding unit and the upper surface of the chuck, a process known as "self-grinding." This self-grinding process is sometimes referred to as chuck grinding.

[0010] Furthermore, in the wafer grinding process, the thickness of the wafer is measured using a measuring unit to grind the wafer to a desired thickness. The measuring unit may be, for example, a non-contact type measuring unit having a sensor that measures the thickness of the wafer without contacting the wafer. The sensor irradiates the wafer with measurement light and receives the light reflected from the front surface and the back surface of the wafer. The thickness of the wafer is then calculated based on both the reflected lights received by the sensor.

[0011] When the self-grinding is performed, the thickness of the chuck decreases, and the distance between the sensor of the measurement unit and the top surface of the chuck changes before and after the self-grinding. In such a case, the measurement unit may not be able to properly measure the thickness of the wafer, and the wafer may not be formed to the desired thickness. Therefore, it is necessary to adjust the position of the sensor after the self-grinding. However, the self-grinding method disclosed in Patent Document 1 does not take into consideration the need to adjust and set the position of the sensor.

[0012] The technology disclosed herein has been made in consideration of the above circumstances, and in a grinding apparatus for grinding a substrate, the position of a thickness measurement unit that measures the thickness of the substrate using a measurement light is set to an appropriate position. Hereinafter, the grinding apparatus and the method for setting the position of the thickness measurement unit according to this embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0013] The grinding apparatus 1 shown in Fig. 1 grinds and thins a wafer W as a substrate. The wafer W is a semiconductor wafer such as a silicon wafer or a compound semiconductor wafer. As shown in Fig. 2, the front surface Wa of the wafer W is a holding surface that is held by a chuck 42 (described later) in the grinding apparatus 1. The back surface Wb of the wafer W, which is opposite the front surface Wa, is a grinding surface that is ground in the grinding apparatus 1.

[0014] 1, the grinding apparatus 1 has a configuration in which a loading / unloading station 2 and a processing station 3 are integrally connected. In the loading / unloading station 2, for example, a cassette C capable of accommodating a plurality of wafers W is loaded and unloaded between the loading / unloading station 2 and the outside. The processing station 3 is equipped with various processing devices that perform desired processing on the wafers W.

[0015] A cassette mounting table 10 is provided in the loading / unloading station 2. A wafer transfer area 20 is provided adjacent to the cassette mounting table 10 on the positive side of the Y axis.

[0016] The wafer transfer region 20 is provided with a wafer transfer device 22 that is movable on a transfer path 21 extending in the X-axis direction. The wafer transfer device 22 has a transfer fork 23 that holds and transfers a wafer W. The transfer fork 23 is movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The wafer transfer device 22 is configured to be able to transfer the wafer W to the cassette C on the cassette mounting table 10, an alignment unit 50 (described later), and a first cleaning unit 60 (described later).

[0017] In the processing station 3, processing such as grinding and cleaning is performed on the wafer W. The processing station 3 includes a transfer unit 30 that transfers the wafer W, a grinding unit 40 that performs a grinding process on the wafer W, an alignment unit 50 that adjusts the horizontal orientation of the wafer W, a first cleaning unit 60 that cleans the wafer W after grinding, a calibration wafer storage unit 70 that stores a calibration wafer as a calibration substrate, and a second cleaning unit 80 that cleans the wafer W after grinding.

[0018] The transfer unit 30 serving as a transfer device is an articulated robot equipped with multiple, for example, three, arms 31. Each of the three arms 31 is configured to be freely rotatable. A transfer pad 32 that suction-holds a wafer W is attached to the arm 31 at the tip end. The arm 31 at the base end is attached to an elevating mechanism 33 that raises and lowers the arm 31 in the vertical direction. The transfer unit 30 is configured to be capable of transferring the wafer W to the grinding unit 40, the alignment unit 50, the first cleaning unit 60, and the second cleaning unit 80. The transfer unit 30 is also configured to be capable of transferring a calibration wafer to the grinding unit 40 and the calibration wafer storage unit 70.

[0019] The grinding unit 40 has a rotary table 41. Four chucks 42 are provided on the rotary table 41 as substrate holders that suction-hold the wafer W. A porous chuck, for example, is used as the chucks 42. The surface of the chucks 42, i.e., the surface that holds the wafer W, has a convex shape in which the center protrudes compared to the edges in a side view. Note that although this protrusion in the center is very small, in the following description, the protrusion in the center of the chuck 42 may be illustrated enlarged for clarity.

[0020] As shown in FIG. 2 , the four chucks 42 are respectively held by four chuck bases 43. The chuck bases 43 are provided with tilt adjustment mechanisms 44 that adjust the relative tilt between each grinding unit (a rough grinding unit 100, a medium grinding unit 110, and a finish grinding unit 120, described below) and the chucks 42. The tilt adjustment mechanism 44 has a fixed shaft 45 provided on the underside of the chuck base 43 and multiple, for example, two, lift shafts 46. Each lift shaft 46 is configured to be extendable and retractable, and raises and lowers the chuck base 43. The tilt adjustment mechanism 44 tilts the chucks 42 and the chuck bases 43 by vertically raising and lowering the other end of the chuck base 43 using the lift shafts 46, starting from one end of the outer periphery of the chuck base 43 (a position corresponding to the fixed shaft 45). This allows the relative tilt between the grinding surfaces of the grinding units at processing positions A1 to A3 and the upper surface of the chucks 42 to be adjusted. The configuration of the tilt adjustment mechanism 44 is not limited to this, and it is sufficient if it can adjust the relative angle (parallelism) of the surface (holding surface) of the chuck 42 with respect to the grinding surface of each grinding portion.

[0021] 1, the four chucks 42 can be moved to a transfer position A0 and processing positions A1 to A3 by rotating the rotary table 41. Furthermore, each of the four chucks 42 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0022] At the transfer position A0, the transfer unit 30 transfers the wafer W. A thickness measurement unit 90 is provided at the transfer position A0 to measure the thickness of the wafer W before or after grinding. The thickness measurement unit 90 measures the thickness of the wafer W at multiple points, for example, three points (center, middle, and outer periphery) equally spaced in the radial direction. The thickness measurement unit 90 also acquires the in-plane thickness distribution of the wafer W and calculates the flatness (TTV: Total Thickness Variation) of the wafer W. The thickness measurement unit 90 may have any configuration, but may have a configuration similar to that of the thickness measurement unit 107 shown in FIG. 3 (described later), i.e., it includes a sensor (probe) 91 and a moving mechanism 92 as a thickness measurement unit. The moving mechanism 92 includes a driving unit 92a, which raises and lowers the sensor 91 and moves the sensor 91 in the radial direction of the wafer W.

[0023] In this embodiment, the thickness measurement unit 90 is provided at the delivery position A0, but the arrangement of the thickness measurement unit 90 is not limited to this. For example, the thickness measurement unit 90 may be arranged independently of the grinding unit 40.

[0024] 1, a rough grinding unit 100 is disposed at processing position A1 and performs rough grinding of the wafer W. A medium grinding unit 110 is disposed at processing position A2 and performs medium grinding of the wafer W. A finish grinding unit 120 is disposed at processing position A3 and performs finish grinding of the wafer W.

[0025] 2, the rough grinding unit 100 at the processing position A1 includes an annular rough grinding stone 101, a rough grinding wheel 102 that supports the rough grinding stone 101, a mount 103 that supports the rough grinding wheel 102, a spindle 104 that rotates the rough grinding wheel 102 via the mount 103, and a drive unit 105 that supports the spindle 104. The drive unit 105 has a built-in motor (not shown), for example, and rotates the spindle 104. As shown in FIG. 1, the rough grinding unit 100 is configured to be movable in the vertical direction along a support column 106 by a drive unit (not shown).

[0026] As described above, the holding surface of the chuck 42 has a convex shape. Therefore, when the wafer W is ground using the rough grinding unit 100, a portion of the annular rough grinding wheel 101 comes into contact with the wafer W. More specifically, the annular rough grinding wheel 101 comes into contact with the wafer W in an arc-shaped manner from the center to the outer peripheral edge of the wafer W. By rotating the chuck 42 and the rough grinding wheel 102 in this state, the entire back surface Wb of the wafer W is ground.

[0027] A thickness measurement unit 107 for measuring the thickness of the wafer W is also provided at the processing position A1. As shown in FIG. 3 , the thickness measurement unit 107 includes a sensor (probe) 108 as a thickness measurement unit and a moving mechanism 109 for raising and lowering the sensor 108. The sensor 108 is a sensor that measures the thickness of the wafer W without contacting the wafer W, and is, for example, a white light confocal optical sensor. The sensor 108 irradiates the wafer W with measurement light and receives light reflected from the front surface Wa and the back surface Wb of the wafer W. A signal representing the measurement result from the sensor 108 is output to a control unit 140 (described later), which calculates the thickness of the wafer W based on both the reflected light received by the sensor. The moving mechanism 109 includes a driving unit 109 a, which raises and lowers the sensor 108 and moves the sensor 108 in the radial direction of the wafer W. In this embodiment, the moving mechanism 109 rotates the sensor 108 around the drive part 109a to move it in the radial direction of the wafer W, but the sensor 108 may also be moved linearly.

[0028] In this embodiment, a white light confocal optical sensor is used as the sensor 108 of the thickness measurement unit 107, but the configuration of the thickness measurement unit 107 is not limited to this, and any measurement unit can be used as long as it measures the thickness of the wafer W in a non-contact manner. A plurality of sensors 108 may be provided. The measurement light irradiated from the sensor 108 is also not particularly limited, and may be pulsed light or continuous light as long as it can be received by the sensor 108 as reflected light.

[0029] The medium grinding unit 110 at the processing position A2 has the same configuration as the rough grinding unit 100. That is, as shown in Fig. 2, the medium grinding unit 110 has an annular medium grinding stone 111, a medium grinding wheel 112, a mount 113, a spindle 114, a drive unit 115, and a support 116. The grain size of the abrasive grains in the medium grinding stone is smaller than the grain size of the abrasive grains in the rough grinding stone.

[0030] 1, a thickness measurement unit 117 is provided at processing position A2 to measure the thickness of wafer W. As shown in Fig. 3, thickness measurement unit 117 has the same configuration as thickness measurement unit 107 described above, that is, it has a sensor (probe) 118 as a thickness measurement unit and a moving mechanism 119 equipped with a driving unit 119a.

[0031] The finish grinding unit 120 at the processing position A3 has the same configuration as the rough grinding unit 100. That is, as shown in Fig. 2, the finish grinding unit 120 has an annular finish grinding stone 121, a finish grinding wheel 122, a mount 123, a spindle 124, a drive unit 125, and a support 126. The grit size of the abrasive grains in the finish grinding stone is smaller than the grit size of the abrasive grains in the medium grinding stone.

[0032] 1, a thickness measurement unit 127 is provided at processing position A3 to measure the thickness of the wafer W. As shown in Fig. 3, thickness measurement unit 127 has the same configuration as the thickness measurement unit 107 described above, that is, it has a sensor (probe) 128 as a thickness measurement unit and a moving mechanism 129 equipped with a driving unit 129a.

[0033] The grinding apparatus 1 described above is provided with a display panel 130 as shown in FIG. The display panel 130 is, for example, a monitor or a touch panel, and may be directly attached to the grinding apparatus 1 or may be remotely viewable. The display panel 130 displays a screen for operating each process performed by the grinding apparatus 1. For example, the display panel 130 displays an operation screen for automatically setting the positions of the sensors 91, 108, 118, and 128 after the chuck 42 has self-grinded. The operation screen for automatically setting the positions of the sensors 91, 108, 118, and 128 will be described later. A signal representing the operation result on the display panel 130 is output to the control unit 140, which will be described later.

[0034] The grinding apparatus 1 described above is provided with at least one control unit 140. The control unit 140 processes computer-executable instructions that cause the grinding apparatus 1 to perform the various steps described in this disclosure. The control unit 140 may be configured to control each element of the grinding apparatus 1 to perform the various steps described herein. In one embodiment, part or all of the control unit 140 may be included in the grinding apparatus 1. The control unit 140 may include a processing unit, a storage unit, and a communication interface. The control unit 140 is realized, for example, by a computer. The processing unit may be configured to read from the storage unit a program that provides logic or routines that enable various control operations and execute the read program to perform various control operations. This program may be stored in the storage unit in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit by the processing unit for execution. The medium may be various computer-readable storage media or a communication line connected to the communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the grinding device 1 via a communication line such as a LAN (Local Area Network).

[0035] Next, a series of wafer processing steps performed in the grinding apparatus 1 configured as above will be described.

[0036] First, a cassette C containing a plurality of wafers W is placed on the cassette mounting table 10 of the carry-in / out station 2. Next, the wafers W in the cassette C are removed by the transport fork 23 of the wafer transport device 22 and transported to the processing station 3. The wafers W transported to the processing station 3 are delivered to the alignment unit 50. In the alignment unit 50, the horizontal orientation of the wafers W is adjusted by adjusting the position of a notch (not shown) formed in the wafers W.

[0037] Next, the wafer W is transported by the transport unit 30 from the alignment unit 50 to the grinding unit 40 and delivered to the chuck 42 at the delivery position A0. At the delivery position A0, the thickness of the wafer W before grinding is measured at multiple points by the thickness measurement unit 90 and the control unit 140. The thickness measurement points of the wafer W by the thickness measurement unit 90 are arbitrary, but may be, for example, three points equally spaced radially. The first measurement point is the center point of the wafer W. The second measurement point is the midpoint of the wafer W, which is a position R / 2 from the center when the radius of the wafer W is R. The third measurement point is a point on the outer periphery of the wafer W.

[0038] Next, the wafer W held by the chuck 42 is moved sequentially to processing positions A1 to A3. At processing position A1, the rough grinding unit 100 rough-grinds the back surface Wb of the wafer W. At processing position A2, the medium grinding unit 110 medium-grinds the back surface Wb of the wafer W. At processing position A3, the finish grinding unit 120 finish-grinds the back surface Wb of the wafer W. These rough grinding, medium grinding, and finish grinding are each performed while measuring the thickness of the wafer W using thickness measurement units 107, 117, and 127 in order to grind the wafer W. The thickness measurement of the wafer W by the thickness measurement units 107, 117, and 127 is performed, for example, at the midpoint of the wafer W.

[0039] Furthermore, after rough grinding, medium grinding, and finish grinding are performed at each of the processing positions A1 to A3, the thickness of the wafer W is measured at multiple points using the thickness measurement units 107, 117, and 127 and the control unit 140 to obtain the in-plane thickness distribution of the wafer W and the flatness of the wafer W. The thickness measurement points of the wafer W by the thickness measurement units 107, 117, and 127 are arbitrary, but may be, for example, three points equally spaced radially (center point, middle point, and outer periphery point). Then, based on the thickness measurement results, the lift shaft 46 of the tilt adjustment mechanism 44 is adjusted to adjust the relative angle (parallelism) of the surface of the chuck 42 with respect to the grinding surfaces of the grinding units 100, 110, and 120.

[0040] Next, the wafer W held by the chuck 42 is moved to the delivery position A0. At the delivery position A0, the thickness of the wafer W after finish grinding is measured at multiple points by the thickness measurement unit 90 and the control unit 140 to obtain the in-plane thickness distribution of the wafer W and the flatness of the wafer W. The thickness measurement points of the wafer W by the thickness measurement unit 90 are arbitrary, but may be, for example, three points (center point, middle point, and outer periphery point) equally spaced in the radial direction.

[0041] Next, the wafer W is transferred from the delivery position A0 to the second cleaning unit 80 by the transfer unit 30, and the front surface Wa and / or the back surface Wb are cleaned while being held on the transfer pad 32.

[0042] Next, the wafer W is transferred from the second cleaning unit 80 to the first cleaning unit 60 by the transfer unit 30, and the front surface Wa and / or the back surface Wb are further cleaned using a cleaning liquid nozzle (not shown).

[0043] Thereafter, the wafer W that has been subjected to all the processes is transferred to the cassette C on the cassette mounting table 10 by the transfer fork 23 of the wafer transfer device 22. In this way, a series of wafer processing steps is completed.

[0044] Here, for example, when the in-plane distribution of the thickness of the wafer W after grinding deviates from a target value, the chucks 42 are self-grinded.

[0045] In self-grinding, the upper surface of the chuck 42 is ground. In this case, the thickness of the chuck 42 is reduced, and the distance between the sensors 91, 108, 118, and 128 of each thickness measurement unit 90, 107, 117, and 127 and the upper surface of the chuck 42 changes before and after self-grinding. Therefore, the positions of the sensors 91, 108, 118, and 128 must be adjusted and set. The positions of the sensors 91, 108, 118, and 128 are height positions (Z-axis positions) set by the moving mechanisms 92, 109, 119, and 129. In other words, the positions of the sensors 91, 108, 118, and 128 are the distance between the sensors 91, 108, 118, and 128 and the surface of the chuck 42 (or the surface Wa of the wafer W). In the following description, the position setting of the sensors 91, 108, 118, and 128 may be referred to as Z-axis setting, and in this embodiment, such position setting is performed automatically, and may be referred to as automatic Z-axis setting.

[0046] 4, an operation screen 200 for performing automatic Z-axis setting of the sensors 91, 108, 118, and 128 is displayed on the display panel 130. The operation screen 200 displays the rotary table 41, an automatic Z-axis setting progress table 210, and a Z-axis setting button 220 as a position setting button.

[0047] As described above, the rotary table 41 is provided with four chucks 42, and the operation screen 200 displays the four chucks 42 as chucks 42A, 42B, 42C, and 42D.

[0048] The Z-axis automatic setting progress table 210 displays the progress of the automatic Z-axis setting of the sensors 91, 108, 118, and 128 for the chuck 42 after self-grinding at the transfer position A0 and the processing positions A1 to A3. The example in Figure 4 shows a case where the target of self-grinding is the chuck 42A. It shows that the automatic Z-axis setting of the sensors 91, 108, 118, and 128 has not been performed at the transfer position A0 and the processing positions A1 to A3 after self-grinding of the chuck 42A.

[0049] The Z-axis setting button 220 is a button for starting automatic Z-axis setting of the sensors 91, 108, 118, and 128 after self-grinding the chuck 42. As will be described later, when self-grinding of the chuck 42 is completed, the user presses the Z-axis setting button 220. A signal representing the result of the user's operation is output to the control unit 140, and automatic Z-axis setting of the sensors 91, 108, 118, and 128 is started.

[0050] Next, a method for automatically setting the Z axis of the sensors 91, 108, 118, and 128 after performing self-grinding of the chuck 42A, for example, will be described.

[0051] First, the chuck 42A is self-grinded (S1 in FIG. 5). For example, the chuck 42A is self-grinded using the finish grinding unit 120 at the processing position A3. In this case, the finish grinding stone 121 and the finish grinding wheel 122 in the finish grinding unit 120 are replaced with a self-grinding stone and grinding wheel for self-grinding. Then, with the self-grinding stone and the upper surface of the chuck 42 in contact with each other, the self-grinding stone and the chuck 42 are rotated to grind the upper surface of the chuck 42.

[0052] When the self-grinding of the chuck 42A is completed in S1, an alarm is output indicating that the automatic Z-axis setting of the sensors 91, 108, 118, and 128 has not been performed (S2 in FIG. 5). Specifically, in the automatic Z-axis setting progress table 210 on the operation screen 200, "automatic Z-axis setting of sensor 91 not performed" is displayed at the transfer position A0. Similarly, "automatic Z-axis setting of sensor 108 not performed" is displayed at the processing position A1, "automatic Z-axis setting of sensor 118 not performed" is displayed at the processing position A2, and "automatic Z-axis setting of sensor 128 not performed" is displayed at the processing position A3.

[0053] The method for outputting the alarm indicating that the automatic Z-axis setting has not been performed may be arbitrary. For example, an alarm may be sounded. Furthermore, control may be performed so that the grinding process of the wafer W is not performed while the alarm indicating that the automatic Z-axis setting has not been performed is being output.

[0054] Next, the user presses the Z-axis setting button 220 on the operation screen 200 (S3 in FIG. 5). A signal indicating that the Z-axis setting button 220 has been pressed is output to the control unit 140, which then automatically sets the Z-axis of the sensors 91, 108, 118, and 128 in sequence.

[0055] The automatic Z-axis setting of the sensors 91, 108, 118, and 128 is performed using a calibration wafer Wp stored in the calibration wafer storage unit 70. The thickness of the calibration wafer Wp is known and is grasped in advance.

[0056] When automatically setting the Z axis of sensors 91, 108, 118, and 128, first, the transfer unit 30 retrieves the calibration wafer Wp stored in the calibration wafer storage unit 70, transfers it to the grinding unit 40, and delivers it to the chuck 42A specified on the operation screen 200 at the delivery position A0 (S4 in Figure 5).

[0057] 6, the sensor 91 is moved up and down, i.e., moved closer to or further away from the calibration wafer Wp, while irradiating the upper surface Wpa of the calibration wafer Wp with measurement light La from the sensor 91. Furthermore, the sensor 91 receives reflected light Lb of the measurement light La reflected by the upper surface Wpa of the calibration wafer Wp (S5 in FIG. 5).

[0058] A signal representing the measurement result from the sensor 91 is output to the control unit 140, which then acquires, for example, the intensity of the reflected light Lb shown in Fig. 7 (S6 in Fig. 5). The horizontal axis in Fig. 7 represents the Z-axis position (height position) of the sensor 91, and the vertical axis represents the intensity of the reflected light Lb.

[0059] The control unit 140 sets the Z-axis position Zp of the sensor 91 where the intensity of the reflected light Lb is at its maximum Ip as the measurement position of the sensor 91 (S7 in FIG. 5). The Z-axis position Zp of the sensor 91 where the intensity of the reflected light Lb is at its maximum Ip is the position where the distance between the bottom surface of the sensor 91 and the top surface Wpa of the calibration wafer Wp is an optimal distance H, as shown in FIG. 6. The optimal distance H is a distance set in accordance with the specifications of the sensor 91, and is the distance at which the sensor 91 can optimally measure the measurement target.

[0060] In S7, the intensity of the reflected light Lb when setting the measurement position of the sensor 91 is set to the maximum intensity Ip, but this is not limiting. For example, as shown in FIG. 7, the intensity of the reflected light Lb may be an optimal intensity Is, which is lower than the maximum intensity Ip. The distance between the bottom surface of the sensor 91 and the top surface Wpa of the calibration wafer Wp shown in FIG. 6 may be within an allowable range of the optimal distance H in the specifications of the sensor 91. The Z-axis position range Zs of the sensor 91, where the intensity of the reflected light Lb becomes the optimal intensity Is, is a position within this allowable range.

[0061] Next, the calibration wafer Wp held by the chuck 42A is moved to the processing position A1. At the processing position A1, the measurement position of the sensor 108 is set in the same manner as the measurement position of the sensor 91 at the transfer position A0. That is, as in S5, the sensor 108 is moved up and down to irradiate the measurement light La of the sensor 108 and receive the reflected light Lb (S8 in FIG. 5). As in S6, the intensity of the reflected light Lb is acquired (S9 in FIG. 5). As in S7, the Z-axis position Zp of the sensor 108 at which the intensity of the reflected light Lb reaches its maximum intensity Ip is set as the measurement position of the sensor 108 (S10 in FIG. 5).

[0062] Next, the calibration wafer Wp held by the chuck 42A is moved to the processing position A2. At the processing position A2, the measurement position of the sensor 118 is set in the same manner as the measurement position of the sensor 91 at the transfer position A0. That is, as in S5, the sensor 118 is moved up and down to irradiate the measurement light La of the sensor 118 and receive the reflected light Lb (S11 in FIG. 5). As in S6, the intensity of the reflected light Lb is acquired (S12 in FIG. 5). As in S7, the Z-axis position Zp of the sensor 118 at which the intensity of the reflected light Lb reaches its maximum intensity Ip is set as the measurement position of the sensor 118 (S13 in FIG. 5).

[0063] Next, the calibration wafer Wp held by the chuck 42A is moved to the processing position A3. At the processing position A3, the measurement position of the sensor 128 is set in the same manner as the measurement position of the sensor 91 at the transfer position A0. That is, as in S5, the sensor 128 is moved up and down to irradiate the measurement light La of the sensor 128 and receive the reflected light Lb (S14 in FIG. 5). As in S6, the intensity of the reflected light Lb is acquired (S15 in FIG. 5). As in S7, the Z-axis position Zp of the sensor 128 at which the intensity of the reflected light Lb reaches a maximum intensity Ip is set as the measurement position of the sensor 128 (S16 in FIG. 5).

[0064] As described above, when the automatic Z-axis setting of the sensors 91, 108, 118, and 128 is performed, the alarm output in S2 indicating that the automatic Z-axis setting has not been performed is canceled (S17 in FIG. 5). Specifically, in the automatic Z-axis setting progress table 210 on the operation screen 200, the display "Automatic Z-axis setting of sensors 91, 108, 118, and 128 not performed" for the machining positions A1, A2, and A3 disappears. Alternatively, the display changes to "Automatic Z-axis setting of sensors 91, 108, 118, and 128 performed," or another display indicating that the Z-axis adjustment of the sensors 91, 108, 118, and 128 has been performed.

[0065] When the automatic Z-axis setting of the sensors 91, 108, 118, and 128 is completed, the calibration wafer Wp held by the chuck 42A is moved to the delivery position A0, and then transferred to the calibration wafer storage unit 70 by the transfer unit 30.

[0066] In the above embodiment, the case where the chuck 42A is self-grinded in S1 has been described, but the same applies to the cases where the other chucks 42B to 42D are self-grinded.

[0067] According to the above embodiment, even if the thickness of the chuck 42 becomes smaller after self-grinding of the chuck 42, the Z-axis of the sensors 91, 108, 118, and 128 can be automatically set, and the measurement positions of the sensors 91, 108, 118, and 128 can be adjusted to appropriate positions. As a result, the thickness of the wafer W before grinding, the thickness of the wafer W after rough grinding by the rough grinding unit 100, the thickness of the wafer W after medium grinding by the medium grinding unit 110, and the thickness of the wafer W after finish grinding by the finish grinding unit 120 can each be set to a desired thickness, and the wafer W can finally be formed to a desired thickness.

[0068] Here, after self-grinding the chuck 42, it is also possible to use a block gauge 300, as shown in FIG. 8 , to set the Z-axis of the sensors 91, 108, 118, and 128. That is, the maintenance panel of the grinding device 1 is opened, and the block gauge 300 is placed between the chuck 42 and the sensors 91, 108, 118, and 128 to set the Z-axis of the sensors 91, 108, 118, and 128. However, in this case, the Z-axis setting of the sensors 91, 108, 118, and 128 is manually performed by the user, which is time-consuming and inefficient. Furthermore, the accuracy of the Z-axis setting is poor because it depends on the user's ability.

[0069] In this regard, according to this embodiment, when the Z-axis setting button 220 on the operation screen 200 is pressed in S3, the Z-axis setting of the sensors 91, 108, 118, and 128 is automatically performed. This allows the Z-axis setting to be performed in a short time. In addition, there is no need to open the maintenance panel of the grinding device 1, which improves the workability of the Z-axis setting. Furthermore, the Z-axis setting can be performed automatically without relying on the ability of the user, which improves the accuracy of the Z-axis setting.

[0070] In this embodiment, when the self-grinding of the chuck 42 is completed in S1, an alarm is output in S2 indicating that automatic Z-axis setting has not been performed for the sensors 91, 108, 118, and 128. This allows the user to confirm whether automatic Z-axis setting has been performed for the sensors 91, 108, 118, and 128 or not.

[0071] Furthermore, by controlling the wafer W not to be ground while an alarm indicating that automatic Z-axis setting has not been performed is output from sensors 91, 108, 118, and 128 in S2, it is possible to prevent the wafer W from being ground to the desired thickness, thereby improving the yield of product wafers.

[0072] As in the above embodiment, after the Z-axis automatic setting of the sensors 91, 108, 118, and 128 is performed using the calibration wafer Wp, the wafer W is subjected to rough grinding by the rough grinding unit 100, medium grinding by the medium grinding unit 110, and finish grinding by the finish grinding unit 120 in this order. At this time, if the thickness of the calibration wafer Wp differs from the thickness of the wafer W before grinding, the sensors 108, 118, and 128 are moved to match the thickness before grinding.

[0073] For example, a case will be described in which the thickness of the calibration wafer Wp is Tp as shown in FIG. 9A and the thickness of the wafer W before rough grinding is Tw as shown in FIG. 9B. The thickness Tw of the wafer W before rough grinding may be measured, for example, using the thickness measurement unit 90 at the transfer position A0, or may be acquired before the wafer W is loaded into the grinding apparatus 1. In this example, the thickness Tw of the wafer W before grinding is smaller than the thickness Tp of the calibration wafer Wp. In such a case, first, as shown in FIG. 9A, automatic Z-axis setting of the sensor 108 is performed based on the thickness Tp of the calibration wafer Wp so that the distance between the bottom surface of the sensor 108 and the top surface Wpa of the calibration wafer Wp becomes an optimal distance H. Next, as shown in FIG. 9B, before rough grinding the wafer W in the rough grinding unit 100, the sensor 108 is moved downward by a distance M. This distance M is the difference between the thickness Tp of the calibration wafer Wp and the thickness Tw of the wafer W before grinding (M = Tp - Tw). In this way, when rough grinding the wafer W, the sensor 108 can be disposed at the optimum distance H, so that the thickness of the wafer W after rough grinding can be made to be the desired thickness.

[0074] 9 has been described for the case where the wafer W is roughly ground by the rough grinding unit 100, the same applies to the intermediate grinding by the intermediate grinding unit 110 and the finish grinding by the finish grinding unit 120. In the intermediate grinding by the intermediate grinding unit 110, the thickness information of the wafer W before the intermediate grinding may be thickness information measured after grinding by the rough grinding unit 100, or may be thickness information set in the recipe. In the finish grinding by the finish grinding unit 120, the thickness information of the wafer W before the finish grinding may be thickness information measured after grinding by the intermediate grinding unit 110, or may be thickness information set in the recipe.

[0075] Similarly, at the delivery position A0 before grinding, if the thickness of the calibration wafer Wp is different from the thickness of the wafer W before grinding, the sensor 91 may be moved to match the thickness before grinding. The thickness of the wafer W before grinding is acquired, for example, before it is loaded into the grinding apparatus 1.

[0076] In the above embodiment, the case has been described where automatic Z-axis setting of the sensors 91, 108, 118, and 128 is performed after self-grinding of the chuck 42, but the timing of this automatic Z-axis setting is not limited to after self-grinding of the chuck 42. For example, the automatic Z-axis setting of this embodiment may be performed when the distance between the chuck 42 and the sensors 91, 108, 118, and 128 changes, such as after replacing the chuck 42 or the sensors 91, 108, 118, and 128.

[0077] In the above embodiments, the automatic Z-axis setting of the sensors 91, 108, 118, and 128 may be performed at the same radial position as the radial measurement position of the wafer W when measuring the thickness of the wafer W using the sensors 91, 108, 118, and 128. Furthermore, the automatic Z-axis setting of the sensors 91, 108, 118, and 128 may be performed at a plurality of points in the radial direction of the calibration wafer Wp. In such a case, when the thickness measurement of the wafer W using the sensors 91, 108, 118, and 128 is performed at a plurality of radial measurement positions of the wafer W, the automatic Z-axis setting of the sensors 91, 108, 118, and 128 may be performed for each of the plurality of radial positions that are the same as the plurality of radial measurement positions.

[0078] For example, when the thickness of the wafer W is measured at a plurality of points, for example, three points in the radial direction (center, middle, and outer periphery) at the transfer position A0, the automatic Z-axis setting of the sensor 91 is performed using a calibration wafer Wp at each of the three points in the radial direction of the calibration wafer Wp (center, middle, and outer periphery). For example, the height position of the sensor 91 is set to height position Z11 at the center point, height position Z12 at the middle point, and height position Z13 at the outer periphery.

[0079] After the Z-axis automatic setting of the sensor 91 is performed using the calibration wafer Wp as described above, the thickness of the wafer W before or after grinding is measured at the transfer position A0. For example, when measuring the thicknesses of the center, intermediate, and outer periphery of the wafer W sequentially, the sensor 91 is first positioned at height position Z11 to measure the thickness of the center of the wafer W. Next, the sensor 91 is positioned at height position Z12 to measure the thickness of the intermediate point of the wafer W, and then the sensor 91 is positioned at height position Z13 to measure the thickness of the outer periphery of the wafer W.

[0080] Similarly, at each of the processing positions A1 to A3, the Z-axis automatic setting of the sensors 108, 118, and 128 is performed at three points (center point, midpoint, and outer periphery point) in the radial direction of the calibration wafer Wp using the calibration wafer Wp. For example, the height positions of the sensors 108, 118, and 128 are set to height position Z21 at the center point, height position Z22 at the midpoint, and height position Z23 at the outer periphery point.

[0081] Then, at each of the processing positions A1 to A3, the midpoint of the wafer W is measured while the wafer W is being ground. At this time, sensors 108, 118, and 128 are each placed at height position Z22. After the wafer W is ground, the thickness of the wafer W is measured sequentially at the center point, midpoint, and outer periphery point. At this time, sensors 108, 118, and 128 are each placed at height positions Z21, Z22, and Z23, respectively.

[0082] According to this embodiment, the radial position of the automatically set Z axis of the sensors 91, 108, 118, and 128 is the same as the radial measurement position of the wafer W, so that the height positions of the sensors 91, 108, 118, and 128 can be appropriately adjusted at the radial position to appropriately measure the thickness of the wafer W.

[0083] Here, the horizontal movement of the sensors 91, 108, 118, 128 by the moving mechanisms 92, 109, 119, 129 may not be perfectly horizontal. Furthermore, the calibration wafer Wp held by the chuck 42 may not be perfectly horizontal, for example, because the chuck 42 is tilted. Therefore, the trajectories of the horizontal movement of the sensors 91, 108, 118, 128 are not necessarily parallel to multiple points in the radial direction of the calibration wafer Wp. Therefore, when thickness measurement of the wafer W is performed at multiple radial measurement positions, the appropriate height positions of the sensors 91, 108, 118, 128 also differ for each radial position.

[0084] In this regard, according to this embodiment, automatic Z-axis setting of sensors 91, 108, 118, and 128 is performed at multiple points in the radial direction, and is performed for each radial measurement position, so that the thickness of the wafer W can be appropriately measured at each radial measurement position.

[0085] When automatic Z-axis setting of the sensors 91, 108, 118, and 128 is performed at multiple points in the radial direction as in this embodiment, it is preferable to set in advance the radial positions of the sensors 91, 108, 118, and 128. A method for setting the radial position of the sensor 91 will be described below, but the method for setting the radial positions of the other sensors 108, 118, and 128 is similar.

[0086] 10A, the transfer unit 30 takes out the calibration wafer Wp stored in the calibration wafer storage unit 70, transfers it to the grinding unit 40, and delivers it to the chuck 42 at the delivery position A0. At this time, the sensor 91 waits at a position radially outward from above the calibration wafer Wp (waiting position P0).

[0087] When the calibration wafer Wp is held by suction on the chuck 42, the movement mechanism 92 rotates the sensor 91 and moves it radially inward, as shown in FIG. 10B . The sensor 91 moves to a position where it can measure the thickness. Since the sensor 91 can measure the thickness above the calibration wafer Wp, the position above the outer periphery of the calibration wafer Wp where the thickness can be measured is set as the outer periphery position P1 of the sensor 91. The outer periphery position P1 is the outer periphery position of the calibration wafer Wp and is a measurement point (outer periphery point) in the radial direction of the wafer W. The outer periphery position P1 set in this manner is output from the movement mechanism 92 to the control unit 140 and registered.

[0088] When the outer peripheral position P1 of the sensor 91 is set, the control unit 140 sets and registers an intermediate position P2 and a central position P3 shown in FIG. 10C. The intermediate position P2 is located at a position R / 2 from the center of the calibration wafer Wp and is a measurement point (midpoint) in the radial direction of the wafer W. The offset amount from the outer peripheral position P1 to the intermediate position P2 is determined in advance, and the intermediate position P2 is set when the outer peripheral position P1 is set. The central position P3 is the central position of the calibration wafer Wp and is a measurement point (midpoint) in the radial direction of the wafer W. The offset amount from the outer peripheral position P1 to the central position P3 is also determined in advance, and the central position P3 is set when the outer peripheral position P1 is set.

[0089] According to this embodiment, the radial positions P1, P2, and P3 of the sensor 91 can be set appropriately, and therefore the Z axis of the sensor 91 can be automatically set appropriately.

[0090] The method for setting the radial positions P1, P2, and P3 of the sensor 91 is not limited to this. For example, a calibration wafer Wp having a recessed center position P3 as shown in Fig. 11 may be used. The thickness T of the calibration wafer Wp at the center position P3 is known in advance and is the smallest within the calibration wafer Wp.

[0091] In this case, the movement mechanism 92 rotates the sensor 91, which is waiting at the waiting position P0, and moves it radially inward. The sensor 91 moves to a position where the thickness T described above is measured. The position of the sensor 91 where the thickness T is measured is then set as the center position P3 of the sensor 91. The offset amount between the center position P3 and the intermediate position P2, and the offset amount between the center position P3 and the outer peripheral position P1 are each predetermined, and once the center position P3 is set, the intermediate position P2 and the outer peripheral position P1 are also set.

[0092] In the above embodiment, the sensors 91, 108, 118, and 128 are set at three radial positions, but the number of radial positions is not limited to this. For example, two radial positions may be set, or four or more radial positions may be set.

[0093] The operation screen 200 for performing automatic Z-axis setting of the sensors 91, 108, 118, and 128, which is displayed on the display panel 130 of the grinding apparatus 1 according to the above embodiment, is not limited to the example shown in Fig. 4. For example, if a contact-type thickness measurement unit is provided at the processing position A1 instead of the non-contact-type thickness measurement unit 107, automatic Z-axis setting of the sensor 108 is not performed at the processing position A1, and the automatic Z-axis setting progress table 210 is left blank.

[0094] Furthermore, although the operation screen 200 shown in FIG. 4 displays the transfer position A0 and the processing positions A1 to A3, the automatic Z-axis setting of the sensor 91 at the transfer position A0, the automatic Z-axis setting of the sensor 108 at the processing position A1, the automatic Z-axis setting of the sensor 118 at the processing position A2, and the automatic Z-axis setting of the sensor 128 at the processing position A3 may each be displayed on a separate screen.

[0095] 4 illustrates an example in which the chuck 42A is self-ground, but it is also possible to display a case in which multiple chucks 42A to 42D are self-ground. In such a case, the Z-axis automatic setting progress table 210 displays an alarm indicating that the Z-axis automatic setting of the sensors 91, 108, 118, and 128 has not been performed for each of the self-ground chucks 42A to 42D.

[0096] 4 has one Z-axis setting button 220, and pressing this Z-axis setting button 220 performs automatic Z-axis setting for the sensors 91, 108, 118, and 128. In this regard, the Z-axis setting button 220 may be provided individually for the transfer position A0 and the processing positions A1 to A3. In such a case, the timing of automatic Z-axis setting for the sensors 91, 108, 118, and 128 at the transfer position A0 and the processing positions A1 to A3 can be set individually.

[0097] In the grinding apparatus 1 of the above embodiment, automatic Z-axis setting of the sensors 91, 108, 118, and 128 is performed using the calibration wafer Wp stored in the calibration wafer storage unit 70, but the calibration wafer Wp may be transported from outside the grinding apparatus 1. In such a case, the calibration wafer storage unit 70 is omitted, and a cassette C containing a plurality of calibration wafers Wp is placed on the cassette mounting table 10 of the carry-in / out station 2.

[0098] The grinding device 1 in the above embodiment has a three-axis configuration including the rough grinding unit 100, the medium grinding unit 110, and the finish grinding unit 120, but may have a one-axis or two-axis configuration. Whether it is one-axis or two-axis, the technology of the present disclosure can be applied to each grinding unit.

[0099] In the above embodiment, the case where the Z-axis of the sensors 91, 108, 118, and 128 is automatically set in the grinding apparatus 1 has been described, but the apparatus to which the method for setting the position of the thickness measurement unit of the present disclosure is applicable is not limited to grinding apparatuses. For example, the technology of the present disclosure can also be applied to an apparatus for measuring the thickness of a substrate before or after etching the substrate.

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0101] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0102] REFERENCE SIGNS LIST 1 Grinding device 42 Chuck 91 Sensor 100 Rough grinding section 101 Rough grinding wheel 108 Sensor 110 Medium grinding section 111 Medium grinding wheel 118 Sensor 120 Finish grinding section 121 Finish grinding wheel 128 Sensor La Measurement light Lb Reflected light W Wafer Wp Calibration wafer

Claims

1. 1. A method for setting the position of a thickness measurement unit for measuring the thickness of a substrate using measurement light in a grinding apparatus for grinding a substrate, comprising: holding a calibration substrate with a substrate holder; irradiating the calibration substrate with the measurement light from the thickness measurement unit while moving the thickness measurement unit close to or away from the calibration substrate; acquiring an intensity of the measurement light reflected by the calibration substrate; and setting the position of the thickness measurement unit at which the acquired intensity of the reflected light is optimal as a thickness measurement position of the substrate.

2. 2. The method for setting the position of a thickness measuring unit according to claim 1, wherein the optimum value is a maximum value of the intensity of the reflected light.

3. 2. The method for positioning a thickness measurement unit according to claim 1, further comprising, when the thickness of the calibration substrate is different from the thickness of the substrate before grinding, moving the thickness measurement unit from the thickness measurement position to match the thickness of the substrate before grinding.

4. 2. The method for setting the position of a thickness measuring unit according to claim 1, further comprising the step of: self-grinding the substrate holding unit before holding the calibration substrate by the substrate holding unit.

5. After performing self-grinding of the substrate holder, outputting an alarm indicating that position setting of the thickness measuring unit has not been performed; 5. The method for setting the position of the thickness measuring unit according to claim 4, further comprising: canceling the alarm after setting the position of the thickness measuring unit to a thickness measuring position of the substrate.

6. 2. The method for setting the position of a thickness measurement unit according to claim 1, wherein when a position setting button for the thickness measurement unit on an operation screen is pressed before the calibration substrate is held by the substrate holding unit, the calibration substrate is transported to the substrate holding unit.

7. 2. The method for setting a position of a thickness measuring unit according to claim 1, wherein the position of the thickness measuring unit is set at the same radial position as a radial measurement position of the substrate when the thickness of the substrate is measured.

8. the thickness of the substrate is measured at a plurality of radial measurement positions on the substrate; 8. The method for setting a position of a thickness measurement unit according to claim 7, wherein the position of the thickness measurement unit is set at each of a plurality of radial positions that are the same as the plurality of radial measurement positions.

9. 9. The method for setting the position of a thickness measuring unit according to claim 8, wherein the plurality of radial measurement positions are positions at which the thickness of the substrate is measured using the thickness measuring unit after the substrate has been ground.

10. A grinding apparatus for grinding a substrate, comprising: a substrate holder; a grinding unit including a grinding wheel for grinding the substrate held by the substrate holding unit or the substrate holding unit, and for moving the grinding wheel relatively to the substrate or the substrate holding unit; a thickness measuring unit for measuring the thickness of the substrate using measurement light; a control unit; The control unit Controlling holding of a calibration substrate by the substrate holder; Control of irradiating the calibration substrate with the measurement light from the thickness measurement unit while moving the thickness measurement unit closer to or further away from the calibration substrate; a control for acquiring, from the thickness measuring unit, an intensity of reflected light of the measurement light reflected by the calibration substrate; and performing control to set the position of the thickness measuring unit where the acquired intensity of the reflected light is at an optimum value as a thickness measurement position of the substrate.

11. The grinding apparatus according to claim 10 , wherein the optimum value is the maximum value of the intensity of the reflected light.

12. The grinding apparatus according to claim 10, wherein the control unit executes control to move the thickness measurement unit from the thickness measurement position to match the thickness of the substrate before grinding when the thickness of the calibration substrate differs from the thickness of the substrate before grinding.

13. The control unit a control to output an alarm indicating that the position setting of the thickness measuring unit has not been performed after performing self-grinding of the substrate holding unit; 11. The grinding apparatus according to claim 10, further comprising: a control for canceling the alarm after setting the position of the thickness measuring unit to a position for measuring the thickness of the substrate.

14. The grinding device according to claim 10 , further comprising an operation screen on which a position setting button for the thickness measuring unit is displayed.

15. a calibration substrate storage unit; a transport device that transports the calibration substrate between the calibration substrate storage unit and the substrate holding unit, The grinding apparatus according to claim 14 , wherein the control unit executes control to transport the calibration substrate to the substrate holding unit by the transport device when a position setting button for the thickness measurement unit on the operation screen is pressed.

16. The grinding apparatus according to claim 10 , wherein the control unit executes control to set the position of the thickness measurement unit at the same radial position as a radial measurement position of the substrate when measuring the thickness of the substrate.

17. The control unit Controlling the measurement of the thickness of the substrate at a plurality of radial measurement positions on the substrate; The grinding device according to claim 10 , further comprising: a control for setting the position of the thickness measuring unit at each of a plurality of radial positions that are the same as the plurality of radial measurement positions.

18. The grinding apparatus according to claim 17 , wherein the plurality of radial measurement positions are positions where the thickness of the substrate is measured using the thickness measuring unit after the substrate has been ground.

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