JP5926042B2 - Method for detecting cracks in plate-like substrates - Google Patents

Description

  The present invention relates to a crack detection method for a plate-like substrate, which detects a crack generated in the plate-like substrate during polishing when a plate-like substrate such as a semiconductor wafer is polished by a polishing apparatus.

  In the semiconductor device manufacturing process, first, divisional lines called streets are formed in a lattice shape on the surface of a substantially disk-shaped wafer made of silicon, a compound semiconductor, etc., and a large number of rectangular regions are defined. An electronic circuit such as an IC or LSI is formed in the region. Thereafter, the wafer is cut along the streets and divided into individual rectangular areas, and a large number of semiconductor chips are manufactured from one wafer. During such a process, in order to reduce the size and weight of the semiconductor chip obtained by dividing the wafer, the wafer is usually ground and polished before the wafer is divided, Processing to a predetermined thickness is performed.

  A polishing apparatus for polishing after grinding a wafer includes a disc-shaped polishing tool including a grindstone for polishing the back surface of the wafer held by a chuck table that holds a workpiece, and the chuck table and the polishing tool It is known that a polishing tool can be efficiently polished by pressing a polishing tool against the back surface of a wafer that is held on a chuck table and rotates while rotating both of them (Patent Document 1).

JP 2010-221378 A

  In the case of polishing a wafer with a polishing apparatus as described in Patent Document 1, an unpredictable load is applied to the wafer due to a phenomenon such as clogging of a grindstone of a polishing tool, and the wafer is cracked. May occur. If cracks occur in the wafer during the polishing process, a change occurs in the contact state between the polishing surface of the wafer and the polishing tool, which causes a problem that uniform polishing cannot be performed.

  The present invention has been made in view of the above circumstances, and its main purpose is to accurately determine that a crack has occurred in the plate-like substrate during the polishing process, and to promptly break the plate-like substrate. An object of the present invention is to provide a method for detecting cracks in a plate-like substrate that can be dealt with.

The method for detecting cracks in a plate-like substrate of the present invention is a method for detecting cracks in a plate-like substrate that detects cracks in the plate-like substrate that occur during polishing in a polishing process for polishing a plate-like substrate with a polishing apparatus. A protective tape adhering step for adhering a protective tape to one surface of the plate substrate, and one surface of the plate substrate on which the protective tape is adhered in the protective tape adhering step. A holding step of mounting and holding on a chuck table rotatably supported by a chuck table supporting means disposed on the other side of the plate-like substrate having one surface held by the chuck table in the holding step A polishing means on which a polishing tool is rotatably mounted is disposed opposite to the surface of the substrate, and the chuck table holding the plate substrate and the polishing tool are rotated, and the processing feed provided in the polishing apparatus is rotated. By the means A polishing step in which polishing is performed by bringing the polishing tool into contact with the other surface of the plate-like substrate by processing and feeding means perpendicularly toward the other surface of the plate-like substrate; and in the polishing step A load measuring step of continuously measuring a load generated by contact between the polishing tool and the plate-like substrate by a load measuring means disposed on either the processing feed means or the chuck table support means; A load storage step for storing the load measured in the load measurement step in a storage means disposed in the polishing apparatus; and the load stored in the load storage step does not exceed a predetermined range. In the processing feed amount control step for controlling the processing feed amount of the polishing means by the processing feed means, and in the processing feed amount control step, the load is reduced beyond the predetermined range. A determination step of cracking the plate-shaped substrate during polishing when it is determined that occurred at least seen including, if cracks on the plate-like substrate in the determining step is determined to have occurred, the plate-like substrate A crack storing step for storing the occurrence of a crack in the storage means, and a direction in which the processing feed of the polishing means by the processing feed means is stopped, and then the polishing means is separated from the plate-like substrate by the processing feed means. A polishing process stopping step for moving the plate, a crack generation display step for displaying that a crack has occurred in the plate-like substrate on the display means disposed in the polishing apparatus, and the plate-like shape in which a crack has occurred from the chuck table And a carrying-out step of carrying out the substrate .

  According to the present invention, when the load generated by the contact between the polishing tool and the plate-like substrate decreases beyond a predetermined range in the processing feed amount control step performed during the polishing step, It is determined that a crack has occurred in the substrate. Therefore, it is possible to accurately determine that a crack has occurred in the plate-like substrate, and it is possible to quickly cope with the crack of the plate-like substrate.

In addition, after it is determined that a crack has occurred in the plate-like substrate, the polishing means is separated from the plate-like substrate and the polishing process is stopped, and the occurrence of the crack and the removal of the plate-like substrate in which the crack has occurred are removed. Made. For this reason, the continuation of the polishing process to the plate-like substrate in which the crack has occurred is avoided, and a uniform polishing process by the subsequent polishing tool can be ensured. In addition, the plate-like substrate to be polished next can be quickly carried into the polishing apparatus, and productivity can be improved.

  According to the present invention, there is provided a method for detecting cracks in a plate-like substrate that can accurately determine that a crack has occurred in the plate-like substrate during polishing and can quickly cope with the crack in the plate-like substrate. There is an effect such as being provided.

(A) The perspective view which shows the protective tape sticking process of the crack detection method of the plate-shaped board | substrate which concerns on one Embodiment, (b) The side view of the board | substrate with which the protective tape was stuck. It is a perspective view of the polish device concerning one embodiment. It is a figure which shows the relationship of the control means with respect to the side view of the process area of the said grinding | polishing apparatus, and a process feed means. It is a perspective view of the polishing tool which the polish device comprises, (a) upper surface side, (b) lower surface side. It is a top view which shows the positional relationship of the board | substrate and grinding | polishing tool of a processing position. It is a figure which shows the relationship of the control means with respect to the side view of the process area of a grinding | polishing apparatus, and a process feed means, Comprising: It is a figure which shows the example of a change by which the load measurement means is arrange | positioned at the process feed means.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Substrate Reference numeral 1 in FIG. 1 denotes a plate-like substrate. The substrate 1 is a substantially disk-shaped semiconductor wafer made of, for example, silicon or a compound semiconductor. In the case of a semiconductor wafer, a plurality of rectangular regions are defined by streets arranged in a lattice pattern on the front surface 1a of the substrate 1, and electronic circuits such as ICs and LSIs are formed in these regions, and the back surface 1b side is It is ground and polished to a predetermined thickness.

  The present embodiment is a crack detection method for detecting cracks in the substrate 1 generated during the polishing process in the polishing process for polishing the back surface 1b of the substrate 1, and the method will be described below in the order of steps.

  First, as shown in FIG. 1, a circular protective tape 9 covering the entire surface 1a is attached to the surface 1a of the substrate 1 (protective tape attaching step). As the protective tape 9, for example, a tape in which an acrylic adhesive having a thickness of about 10 to 20 μm is applied to one side of a base material such as polyethylene having a thickness of about 100 to 200 μm is preferably used. Is adhered to the surface 1a of the substrate 1 via an adhesive.

  Next, the substrate 1 with the protective tape 9 attached to the front surface 1a is carried into the polishing apparatus 10 shown in FIG. 2 and the back surface 1b is polished. Hereinafter, the configuration of the polishing apparatus 10 and the polishing operation by the polishing apparatus 10 will be described. During the polishing operation, a detection method according to an embodiment is included.

[2] Configuration of Polishing Apparatus The polishing apparatus 10 has a rectangular parallelepiped base 11, and a wall 12 is erected at one end in the longitudinal direction of the base 11 (the end on the back side in FIG. 2). Has been. In FIG. 2, the longitudinal direction, the width direction, and the vertical direction of the base 11 are set as the Y direction, the X direction, and the Z direction, respectively.

  On the base 11, the wall 12 side from the substantially middle part in the Y direction is a processing area 11A where the polishing process is actually performed, and the opposite side carries the substrate 1 before processing into the processing area 11A, and after processing. A loading / unloading area 11B for unloading the substrate 1 is used.

(A) Mechanism of processing area A rectangular recess 13 is formed in the processing area 11A, and a vacuum chuck type circle is provided in the recess 13 via a moving table (chuck table support means) 14. A plate-like chuck table 70 is provided so as to be movable in the Y direction.

  As shown in FIG. 3, the movable table 14 is provided with a disk-like support plate 143 on a base 141 via a plurality of legs 142, and extends in the Y direction arranged in the base 11. A base 141 is slidably attached to a guide rail (not shown), and is reciprocated in the Y direction by a slide mechanism 15. The plurality of leg portions 142 are arranged on the outer peripheral portion of the support plate 143 at equal intervals in the circumferential direction.

  The slide mechanism 15 has a configuration in which a ball screw 151 extending in the Y direction and screwed to and coupled to the base 141 is rotated by a motor (not shown), and the moving table 14 is moved to the base by rotating the ball screw 151 by the motor. 141 and 141 move in the Y direction according to the rotation direction of the ball screw 151. Both ends of the ball screw 151 are rotatably supported by bearings 152 fixed to the base 11.

  As shown in FIG. 3, the chuck table 70 is rotatably supported at the center of the moving table 14 via a bearing 71 and is rotated by a rotation driving mechanism 72 provided on the moving table 14. The diameter of the horizontal upper surface 701 of the chuck table 70 that is the holding surface of the substrate 1 is slightly larger than that of the substrate 1, and the substrate 1 is placed concentrically on the holding surface 701, and is rotated by the rotation of the chuck table 70.

  Bellows-shaped covers 15 and 16 that cover the moving path of the moving table 14 are provided on both sides of the moving table 14 in the moving direction. These covers 15 and 16 prevent the polishing dust and the like from falling on the moving path of the moving table 14 and expand and contract as the moving table 14 moves.

  The chuck table 70 is positioned at a predetermined processing position when the movable table 14 moves to the wall 12 side. A polishing means 20 is disposed above the processing position. The polishing means 20 is attached to the front surface side of the wall portion 12 through a slider 32 and a guide rail 31 so as to be lifted and lowered by the processing feed means 30.

  As shown in FIG. 3, the polishing means 20 includes a cylindrical spindle housing 22 whose axial direction extends in the vertical direction, a spindle shaft 23 coaxially and rotatably supported in the spindle housing 22, and a spindle shaft 23. Are configured by a motor 24 that rotates and rotates, a disk-like mount 25 that is coaxially fixed to the lower end of the spindle shaft 23, and a polishing tool 26 that is detachably attached to the mount 25.

  Further, a position detecting means 37 of the polishing means 20 for detecting the position in the feed direction of the polishing means 20, that is, the height position, is disposed between the slider 32 and the wall portion 12. Examples of the position detection unit 37 include a combination of a linear scale and a scale sensor.

  As shown in FIG. 4, the polishing tool 26 has a polishing pad 262 fixed to the lower surface of a disk-shaped frame 261, and the frame 261 uses a plurality of screw holes 263 formed on the upper surface of the frame 261. Is detachably fixed to the lower surface of the mount 25. The polishing pad 262 is selected according to the substrate 1. For example, a felt grindstone or the like in which abrasive grains are dispersed in a felt and fixed with an appropriate bonding agent is used.

  As shown in FIG. 3, the processing feed means 30 is configured to rotate a ball screw 33 screwed and connected to the slider 32 with a motor 34, and on the front surface of the slider 32 (the left surface in FIG. 3). The holder 35 is fixed. The ball screw 33 extends in the vertical direction, and upper and lower ends thereof are rotatably supported by a bearing 36 fixed to the wall portion 12. In the polishing means 20, the spindle housing 22 is fixed to the slider 32 via a holder 35. According to the processing feed means 30, the ball screw 33 is rotationally driven by the motor 34, so that the slider 32 is driven up and down, whereby the polishing means 20 is moved up and down integrally with the slider 32.

  The substrate 1 is polished by rotating the chuck table 70 and the polishing tool 26 while lowering the polishing unit 20 vertically by the processing feed unit 30 and polishing the back surface 1b of the substrate 1 that is held by the chuck table 70 and rotates. This is done by pressing the pad 262 from above. As shown in FIG. 5, the processing position by the polishing means 20 is set to a position where the outer peripheral edge of the polishing pad 262 passes through the center (indicated by O) of the rotating substrate 1, and the entire back surface 10b is thereby polished. The In addition, although the arrow shown to the board | substrate 1 of FIG. 5 and the polishing pad 262 is an example of each rotation direction, a rotation direction is not limited to this.

  When the substrate 1 is polished, a load is generated when the polishing pad 262 is pressed against and contacts the back surface 1 b of the substrate 1. The load is continuously measured by the load measuring means 40 disposed on the plurality of legs 142 of the moving table 14 that supports the chuck table 70 shown in FIG. The load measuring means 40 is of a generally well-known configuration configured to output a voltage signal corresponding to the load when a vertical compressive load is applied. The load measuring means 40 is disposed so as to be sandwiched between the upper ends of the leg portions 142 and the support plate 143, and the load generated when the polishing pad 262 of the polishing tool 26 presses the substrate 1 is applied to the chuck table 70. Then, it is transmitted to the load measuring means 40 through the bearing 71 and the support plate 143.

  The load measurement value continuously measured by the load measuring means 40 is supplied to the control means 50. In this case, the number of the load measuring means 40 corresponds to the number of the leg portions 142 (for example, three), and the total value of the measured values of the plurality of load measuring means 40 is supplied to the control means 50. The control means 50 includes a CPU 51 that performs arithmetic processing according to a control program, a ROM 52 that stores a control program and the like, a readable / writable RAM (storage means) 53 that stores arithmetic results and the like, an input interface 54 and an output interface 55. ing.

  A load measurement value signal continuously measured by the load measuring means 40 is input to the input interface 54. Further, a detection signal from the position detection unit 37 of the polishing unit 20 is also input to the input interface 54. Further, a control signal is sent from the output interface 55 to the motor 34 and the display means 80 of the processing feed means 30. The display means 80 is, for example, a flashing red light or the like, which emits flashing light when an ON signal is sent, and can recognize that the operator is turned on. Further, alarm means for generating an alarm sound at the same time when the display of the display means 80 is turned on may be provided.

(B) Mechanism of carry-in / carry-out area As shown in FIG. 1, a rectangular recess 18 is formed in the carry-in / carry-out area 11 </ b> B. A robot 60 having a fork 60b attached to the tip of a link-type horizontal turning arm 60a is installed.

  Then, around the recess 18, as viewed from above, in a counterclockwise direction, the cassette 61, the positioning table 62, the carry-in arm 63 in which the suction pad 63 b is attached to the tip of the horizontal swivel arm 63 a, and the carry-in arm 63. , A carry-out arm 64 having a horizontal swivel arm 64a and a suction pad 64b, a spinner-type cleaning device 65, and a cassette 66 are arranged.

  The cassette 61, the positioning table 62, and the carry-in arm 63 are means of a system for carrying the substrate 1 into the chuck table 70. The carry-out arm 64, the cleaning device 65, and the cassette 66 carry out the processed substrate 1 from the chuck table 70. It is a means of the system to do. Although the two cassettes 61 and 66 have the same structure, they are referred to as a carry-in cassette 61 and a carry-out cassette 66 according to applications. The cassettes 61 and 66 are accommodated in a state where a plurality of substrates 1 are stacked and can be transported, and are set at predetermined positions on the base 11.

  The carry-in cassette 61 accommodates the plurality of substrates 1 before polishing, with the protective tape 9 attached to the surface as described above. The robot 60 takes out one substrate 1 from the carry-in cassette 61 by raising and lowering and turning the arm 60a and gripping the fork 60b, and places the substrate 1 on the positioning table 62 with the back surface 1b facing up. It has a function to place.

  The substrate 1 placed on the positioning table 62 is positioned at a certain carry-in position. The carry-in arm 63 has a function of adsorbing the substrate 1 on the positioning table 62 to the adsorption pad 63 b and turning the arm 63 a to place the substrate 1 on the chuck table 70. On the other hand, the carry-out arm 64 has a function of sucking the processed substrate 1 on the chuck table 70 onto the suction pad 64b and rotating the arm 64a to transfer the substrate 1 into the cleaning device 65. The cleaning device 65 has a function of rotating the substrate 1 after the substrate 1 is washed with water, shaking off the moisture, and drying the substrate 1. Then, the substrate 1 cleaned and dried by the cleaning device 65 is transferred and accommodated in the carry-out cassette 66 by the robot 60.

  When the substrate 1 is loaded into or unloaded from the chuck table 70 by the loading arm 63 and the unloading arm 64, the movable table 14 is moved to the loading / unloading area 11B side to a predetermined loading / unloading position. Positioned.

  The processing position of the substrate 1 by the polishing means 20 is an area moved by a predetermined distance from the loading / unloading position toward the wall 12, and the chuck table 70 is moved to the processing position and the loading / unloading position by the movement of the movable table 14. To and from.

[3] Operation of Polishing Apparatus Next, the operation of polishing the back surface 1b of the substrate 1 by the polishing apparatus 10 will be described. During this operation, the polishing method of the present invention is included.

  One substrate 1 in the carry-in cassette 61 is taken out by the robot 60, placed on the positioning table 62 and positioned at a predetermined carry-in position, and then the chuck placed at the carry-in / out position by the carry-in arm 63. It is placed on the holding surface 701 of the table 70 via the protective tape 9. The substrate 1 is placed concentrically on the holding surface 701. Thereafter, the chuck table 70 is operated in vacuum, and the substrate 1 is sucked and held on the holding surface 701 (holding step).

  Next, the moving table 14 moves and the substrate 1 is sent to the processing position, and the back surface 1b of the substrate 1 is polished by the polishing means 20 (polishing step). As described above, the polishing of the substrate 1 is performed by lowering the polishing means 20 vertically by the processing feeding means 30 while rotating both the chuck table 70 and the polishing tool 26 and holding the chuck table 70 to rotate. This is done by pressing the polishing pad 262 against 1b from above.

Here, the following operation is always performed while the substrate 1 is being polished.
First, the load generated by the contact between the polishing tool 26 and the substrate 1 is continuously measured by the load measuring means 40 disposed on the moving table 14 (load measuring step). The load measurement value continuously measured by the load measurement means 40 is stored in the RAM 53 of the control means 50 (load storage process). Further, the control unit 50 sends a signal to the motor 34 so that the load stored in the RAM 53 does not exceed a predetermined range, and controls the machining feed amount of the machining feed unit 30 below the polishing unit 20. (Processing feed amount control process). For example, if the load in an appropriate polishing state is about 100 N, the predetermined range of load is set to 100 ± 10 N, for example.

  Thus, the control pad 50 presses the polishing pad 262 against the substrate 1 with an appropriate load by controlling the processing feed amount of the polishing means 20 by the processing feed means 30. When a predetermined polishing time has elapsed, the polishing means 20 is retracted upward by the processing feed means 30, and then the rotation of the chuck table 70 is stopped and the chuck table 70 is returned to the loading / unloading position. Then, after the suction and holding of the substrate 1 on the chuck table 70 is released, the substrate 1 is picked up from the chuck table 70 by the carry-out arm 64 and transferred into the cleaning device 65, and is washed and dried in the cleaning device 65. . Next, the substrate 1 is transferred and accommodated in the carry-out cassette 66 by the robot 60.

  The above is a cycle in which a single substrate 1 is polished and then washed and collected. This cycle is repeated. When all the substrates 1 in the carry-in cassette 61 have been processed, the substrate 1 is moved to the next step together with the carry-out cassette 66.

  The above is the operation to finish the polishing properly. When the load measured by the load measuring means 40 in the polishing step and stored in the RAM 53 decreases beyond the predetermined range, the polishing process is performed. It is determined that a crack has occurred in the inner substrate 1 (determination step).

  Since the substrate 1 is held on the chuck table 70 via the protective tape 9, when a crack occurs in the substrate 1, the portion where the strength is reduced due to the crack is partially pushed by the polishing means 20 and sinks into the protective tape 9. As a result, the phenomenon that the load is lost occurs, and the measured load decreases. For these reasons, it is determined that a crack has occurred in the substrate 1 when the load decreases.

  When it is determined that the substrate 1 has been cracked in this way, the fact that the substrate 1 has been cracked is stored in the RAM 53 of the control means 50 (crack storing step), and at the same time, polishing by the processing feed means 30 is performed. The processing feed of the means 20 is stopped, the polishing means 20 moves upward and is separated from the substrate 1, and the polishing operation is stopped (polishing processing stop step). Further, an ON signal is sent from the control means 50 to the display means 80, and the display means 80 is brought into a "display" state (crack generation display process). For example, if the display means 80 is the flashing red light, the flashing light is emitted. The operator recognizes that a crack has occurred in the substrate 1 by turning on the display of the display means 80.

  On the other hand, in the processing area 11A, the chuck table 70 is returned from the processing position to the loading / unloading position after the polishing is stopped, and the substrate 1 released from the chucking and holding of the chuck table 70 is taken up by the unloading arm 64. It is transferred into the cleaning device 65. Here, the cleaning by the cleaning device 65 is not performed, and the substrate 1 is transferred and accommodated in the carry-out cassette 66 by the robot 60. The operator confirms where the broken substrate 1 is stored in the carry-out cassette 66 by the operator, and performs another process when moving to the next step.

[4] Effects of Crack Detection Method According to the above-described embodiment, the load generated by the contact between the polishing pad 262 of the polishing tool 26 and the substrate 1 in the processing feed amount control step performed during the polishing step is performed. When it decreases beyond a predetermined range, it is determined that a crack has occurred in the substrate 1. Therefore, it is possible to accurately determine that a crack has occurred in the substrate 1 and to quickly deal with the crack in the substrate 1.

  Further, after it is determined that a crack has occurred in the substrate 1, the polishing means 20 is separated from the substrate 1 and the polishing process is stopped, and the operator can know the occurrence of the crack by the display means 80, At the same time, the substrate 1 in which cracking has occurred is carried out. For this reason, the continuation of the polishing process on the substrate 1 in which the crack has occurred is avoided. If the substrate 1 that has been cracked is polished as it is, the polishing pad 262 is damaged by the cracked portion, and if subsequent substrates 1 are polished one after another while being damaged, the substrate 1 may not be uniformly polished. There is. However, in this embodiment, if it is determined that a crack has occurred, the polishing is quickly avoided and the polishing pad 262 separates from the cracked substrate 1, so that a uniform polishing process by the subsequent polishing tool 26 is ensured. Further, since the substrate 1 to be polished next can be quickly carried into the polishing apparatus 10, productivity can be improved.

  In the polishing apparatus 10 of the above embodiment, the load measuring means 40 for continuously measuring the load generated when the polishing tool 26 is pressed against the substrate 1 is disposed on the chuck table 70, but the load measuring means 40 is As shown in the modified example of FIG. 6, the load can be measured in the same manner even when the processing feed means 30 is arranged instead of the chuck table 70.

  The processing feed means 30 shown in FIG. 6 has a disk-shaped load receiving plate 38 that is disposed below the holder 35 and receives a repulsion of the load from the spindle shaft 23. The load receiving plate 38 and the holder 35 are provided. A plurality of (for example, three) load measuring means 40 are sandwiched between the two. The plurality of load measuring means 40 are arranged at equal intervals in the circumferential direction.

  According to this configuration, the load generated when the polishing pad 262 of the polishing tool 26 is pressed against the substrate 1 is transmitted to the load measuring means 40 through the polishing tool 26, the mount 25, the spindle shaft 23, and the load receiving plate 38. The total value of the load measurement values continuously measured by each load measuring means 40 is input to the input interface 54 of the control means 50.

  As described above, when the load measuring means 40 is disposed on the polishing means 20 side, for example, the movement amount of the chuck table 70 is large, or a plurality of chuck tables 70 are installed on a rotary turntable. (See Japanese Patent Application Laid-Open No. 2007-305628), cases where it is difficult to route the wiring to the load measuring means 40, and the wiring can be relatively simplified, which is a preferable configuration.

DESCRIPTION OF SYMBOLS 1 ... Plate-shaped board | substrate 9 ... Protection tape 10 ... Polishing apparatus 14 ... Moving stand (chuck table support means)
DESCRIPTION OF SYMBOLS 20 ... Polishing means 26 ... Polishing tool 30 ... Processing feed means 40 ... Load measuring means 53 ... RAM (memory | storage means)
70 ... Chuck table 80 ... Display means

Claims (1)

In a polishing process for polishing a plate-like substrate with a polishing apparatus, a crack detection method for a plate-like substrate for detecting a crack in the plate-like substrate generated during the polishing process,
A protective tape attaching step of attaching a protective tape to one surface of the plate-like substrate;
One surface of the plate-like substrate to which the protective tape has been attached in the protective tape attaching step is placed on a chuck table that is rotatably supported by chuck table support means disposed in the polishing apparatus. Holding process to hold;
In the holding step, a polishing means on which a polishing tool is rotatably mounted so that one surface faces the other surface of the plate-like substrate held by the chuck table is disposed, and the plate-like substrate is held. The plate-like substrate is rotated by rotating the chuck table and the polishing tool and vertically feeding the polishing means toward the other surface of the plate-like substrate by the processing feed means provided in the polishing apparatus. A polishing step of performing polishing by bringing the polishing tool into contact with the other surface of
In the polishing step, load measurement is performed by continuously measuring the load generated by the contact between the polishing tool and the plate-like substrate by the load measuring means disposed on either the processing feed means or the chuck table support means. Process,
A load storage step of storing the load measured in the load measurement step in a storage means disposed in the polishing apparatus;
A processing feed amount control step of controlling a processing feed amount of the polishing means by the processing feed means so that the load stored in the load storage step does not exceed a predetermined range,
In the processing feed amount control step, a determination step of determining that a crack has occurred in the plate-like substrate during polishing when the load decreases beyond the predetermined range,
At least look at including the,
When it is determined that the crack has occurred in the plate-like substrate in the determination step,
A crack storing step of storing in the storage means that a crack has occurred in the plate-like substrate;
A polishing process stopping step of stopping the process feed of the polishing means by the process feed means, and then moving the polishing means away from the plate substrate by the process feed means;
A crack generation display step for displaying that a crack has occurred in the plate-like substrate on the display means disposed in the polishing apparatus;
An unloading step of unloading the plate-shaped substrate with cracks from the chuck table;
The crack detection method of the plate-shaped board | substrate characterized by including at least .

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