JP2015072993A - Cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting method capable of improving productivity by reducing the time required for kerf checking.SOLUTION: A cutting method comprises the steps of: holding a workpiece (11) (holding step); forming a first kerf (13a) by cutting the workpiece by a first blade (48a) and forming a second kerf (13b) by cutting the workpiece by a second blade (48b) facing the first blade (cutting step); detecting the state between the first kerf and the second kerf (detection step); and calculating an inter-kerf distance (D1) between the first kerf and the second kerf from the positions of the first blade and the second blade in the cutting step after the cutting step and before the detection step) (inter-kerf distance calculation step). When the calculated inter-kerf distance becomes more than or equal to the closest approach distance between first imaging means (14a) and second imaging means (14b), the detection step images the first kerf by the first imaging means and images the second kerf by the second imaging means.

Description

  The present invention relates to a cutting method for cutting a workpiece such as a semiconductor wafer, and more particularly to a cutting method for cutting a workpiece with a cutting device including a plurality of imaging units.

  A workpiece such as a semiconductor wafer is cut by, for example, a cutting device including an annular blade. In recent years, in order to increase the efficiency of this cutting, a cutting device having a plurality of blades has been used (for example, see Patent Document 1).

  The cutting apparatus disclosed in Patent Document 1 includes two chuck tables that hold workpieces, two blades that cut workpieces held on the chuck tables, and two corresponding imaging units. ing. According to this cutting apparatus, the workpieces held on the respective chuck tables can be imaged by the imaging unit, and two workpieces can be cut simultaneously.

  By the way, when the workpiece is cut by the above-described cutting apparatus, a kerf check is performed to check the state of the cut (kerf) after cutting (see, for example, Patent Document 2). In this kerf check, the kerf formed on the workpiece by cutting is imaged by an imaging unit, and the width of the kerf, the size of chipping, and the like are confirmed.

JP 2006-156809 A JP 2011-66233 A

  However, the above-described kerf check has a problem that it takes a certain amount of time because the kerf is imaged after air is blown around the kerf and adhering water (cutting water) is removed.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a cutting method capable of shortening the time required for the kerf check and increasing the productivity.

  According to the present invention, the holding means for holding the workpiece, the first blade for cutting the workpiece held by the holding means, and the second blade disposed to face the first blade, A cutting method for cutting a workpiece with a cutting device including a first imaging means and a second imaging means for imaging the workpiece held by the holding means, the workpiece being held by the holding means The holding step and the workpiece held by the holding means are cut by the first blade to form the first kerf, and the workpiece is processed by the second blade disposed facing the first blade. A cutting step of cutting an object to form a second kerf, a detection step of detecting a state of the first kerf and the second kerf formed in the cutting step, and after performing the cutting step, Before performing the detection step, the cutting step An inter-calf distance calculating step for calculating an inter-calf distance between the first kerf and the second kerf from the positions of the first blade and the second blade, and in the detecting step, When the inter-calf distance calculated in the inter-calf distance calculating step is equal to or greater than the distance at which the first imaging unit and the second imaging unit are closest to each other, the first kerf is imaged by the first imaging unit. The second kerf is imaged by a second imaging means to detect the state of the first kerf and the second kerf, respectively, and the first imaging means and the second imaging means are detected from a distance that can be closest to the second kerf. When the distance between the kerfs is small, the first kerf and the second kerf are imaged by the imaging unit closer to the first kerf and the second kerf of the first imaging unit and the second imaging unit. To check the state of the first kerf and the second kerf, respectively. Cutting method which is characterized in that there is provided.

  In the cutting method of the present invention, the distance between the first kerf formed by the first blade and the second kerf formed by the second blade is equal to or greater than the closest distance at which the first imaging unit and the second imaging unit are closest to each other. In this case, the first kerf is imaged by the first imaging unit and the second kerf is imaged by the second imaging unit to detect the states of the first kerf and the second kerf.

  As described above, according to the present invention, the first kerf and the second kerf can be simultaneously imaged by the first imaging unit and the second imaging unit according to the distance between the first kerf and the second kerf. In addition, the time required for the kerf check can be shortened and the productivity can be improved as compared with the method of imaging a plurality of kerfs with one imaging means.

It is a perspective view showing typically an example of composition of a cutting device with which a cutting method concerning this embodiment is implemented. It is a perspective view which shows typically the peripheral structure of the cutting unit with which a cutting device is provided. It is a partial cross section side view which shows typically the holding | maintenance step of the cutting method which concerns on this Embodiment. It is a partial cross section side view which shows typically the cutting step of the cutting method which concerns on this Embodiment. It is a partial cross section side view which shows typically the detection step of the cutting method which concerns on this Embodiment. It is a figure which shows typically the example of the image acquired at a detection step. It is a partial cross section side view showing typically another example of a cutting step. It is a partial cross section side view showing typically another example of a detection step.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The cutting method according to the present embodiment includes a holding step (see FIG. 3), a cutting step (see FIGS. 4 and 7), a calf distance calculating step (see FIGS. 4 and 7), and a detecting step (FIG. 5 and FIG. 5). 8).

  In the holding step, a workpiece such as a semiconductor wafer is held on a chuck table (holding means) of the cutting apparatus. In the cutting step, the workpiece held on the chuck table is cut with the first blade and the second blade of the cutting device to form the first kerf and the second kerf.

  In the inter-calf distance calculating step, the inter-calf distance between the first kerf and the second kerf is calculated based on the positions of the first blade and the second blade in the cutting step. In the detection step, one or both of the first imaging unit (first imaging unit) and the second imaging unit (second imaging unit) are used based on the calculated distance between the kerfs, and the first kerf and the second kerf are detected. Detect state. Hereinafter, the cutting method according to the present embodiment will be described in detail.

  First, a cutting apparatus in which the cutting method according to the present embodiment is performed will be described. FIG. 1 is a perspective view schematically showing a configuration example of a cutting device, and FIG. 2 is a perspective view schematically showing a peripheral structure of a cutting unit provided in the cutting device. As shown in FIG. 1, the cutting device 2 includes two chuck tables (holding means) 4a and 4b for sucking and holding a plate-like workpiece 11 (see FIG. 3) typified by a semiconductor wafer.

  Below the chuck tables 4a and 4b, X-axis moving mechanisms 6a and 6b for moving the chuck tables 4a and 4b in the X-axis direction are provided. Also, prismatic column portions 8a and 8b are arranged so as to sandwich the X-axis moving mechanisms 6a and 6b. Two bridging portions 10a and 10b are provided on the upper surfaces of the pillar portions 8a and 8b, respectively, which bridge the pillar portion 8a and the pillar portion 8b.

  Each of the bridging portions 10a and 10b is formed in a plate shape that is long in the Y-axis direction, and is disposed so that the back surfaces thereof face each other. By this bridge | crosslinking part 10a, 10b and pillar part 8a, 8b, the 1st cutting unit 12a, the 2nd cutting unit 12b (refer FIG. 2), the 1st imaging unit (1st imaging means) 14a, the 2nd imaging unit (1st A gate-type support structure is formed to support the (two image pickup means) 14b.

  In the bridging portion 10a, the first cutting unit moving mechanism 16a and the first cutting unit moving mechanism 16a for moving the first cutting unit 12a and the second cutting unit 12b in the Y-axis direction and the Z-axis direction are disposed on the surface side opposite to the back surface facing the bridging portion 10b. A two-cutting unit moving mechanism 16b is provided.

  Further, in the bridging portion 10b, the first imaging unit moving mechanism 18a and the second imaging unit that move the first imaging unit 14a and the second imaging unit 14b in the Y-axis direction are disposed on the surface side opposite to the back surface facing the bridging portion 10a. A unit moving mechanism 18b is provided.

  Each of the X-axis moving mechanisms 6a and 6b includes a pair of X-axis guide rails 20a and 20b parallel to the X-axis direction. The X-axis guide rails 20a and 20b include X-axis moving tables 22a and 22b, respectively. It is slidably installed.

  Nut portions (not shown) having screw holes are respectively provided on the lower surface side of the X-axis moving tables 22a and 22b. The screw holes of these nut portions are parallel to the X-axis guide rails 20a and 20b. X-axis ball screws 24a and 24b are screwed together.

  X-axis pulse motors 26a and 26b are connected to one ends of the X-axis ball screws 24a and 24b, respectively. By rotating the X-axis ball screws 24a and 24b with the X-axis pulse motors 26a and 26b, the X-axis moving tables 22a and 22b move in the X-axis direction along the X-axis guide rails 20a and 20b.

  Chuck tables 4a and 4b for sucking and holding the workpiece 11 are provided on the X-axis moving tables 22a and 22b, respectively. Around the chuck tables 4a and 4b, clamps 28a and 28b for holding and fixing an annular frame 23 (see FIG. 3) for supporting the workpiece 11 from four directions are provided.

  Each of the chuck tables 4a and 4b is connected to a rotation mechanism (not shown) and rotates around the Z axis. The surfaces of the chuck tables 4a and 4b are holding surfaces that hold the workpiece 11 by suction. A negative pressure of a suction source (not shown) acts on the holding surface through a flow path (not shown) formed inside the chuck tables 4a and 4b, and a suction force for sucking the workpiece 11 is generated.

  As shown in FIG. 2, the first cutting unit moving mechanism 16a and the second cutting unit moving mechanism 16b share a pair of Y-axis guide rails 30 that are arranged on the surface side of the bridging portion 10a and are parallel to the Y-axis direction. I have. On the Y-axis guide rail 30, Y-axis moving tables 32a and 32b constituting the first cutting unit moving mechanism 16a and the second cutting unit moving mechanism 16b are slidably installed.

  Nut portions having screw holes are provided on the back surfaces of the Y-axis moving tables 32a and 32b, and Y-axis ball screws 34a and 34b parallel to the Y-axis guide rail 30 are provided in the screw holes of these nut portions. Are screwed together.

  A Y-axis pulse motor 36 is connected to one end of each of the Y-axis ball screws 34a and 34b (the Y-axis pulse motor on the second cutting unit moving mechanism 16b side is not shown). When the Y axis ball screws 34 a and 34 b are rotated by the Y axis pulse motor 36, the Y axis movement tables 32 a and 32 b move in the Y axis direction along the guide rail 30.

  The first cutting unit moving mechanism 16a and the second cutting unit moving mechanism 16b are respectively a pair of Z-axis guide rails 38a and 38b that are arranged on the surface side of the Y-axis moving tables 32a and 32b and are parallel to the Z-axis direction. It has. Z-axis moving tables 40a and 40b are slidably installed on the Z-axis guide rails 38a and 38b, respectively.

  Nut portions (not shown) having screw holes are respectively provided on the back surfaces of the Y-axis moving tables 40a and 40b. The screw holes of these nut portions are parallel to the Z-axis guide rails 38a and 38b. A Z-axis ball screw (not shown) is screwed.

  Z-axis pulse motors 42a and 42b are connected to one end of the Z-axis ball screw, respectively. If the Z-axis ball screw is rotated by the Z-axis pulse motors 42a and 42b, the Z-axis moving tables 40a and 40b move in the Z-axis direction along the Z-axis guide rails 38a and 38b.

  A first cutting unit 12a and a second cutting unit 12b are disposed below the Z-axis moving tables 40a and 40b via arm portions 44a and 44b. If the Y-axis movement tables 32a and 32b and the Z-axis movement tables 40a and 40b are moved as described above, the first cutting unit 12a and the second cutting unit 12b also move in the Y-axis direction and the Z-axis direction.

  Each of the first cutting unit 12a and the second cutting unit 12b includes an annular first blade 46a (see FIG. 1) and a second blade 46b (see FIG. 2). The first blade 46a and the second blade 46b are attached to the tip portions of spindles 48a and 48b (see FIG. 4) that rotate about the Y axis, and face each other.

  The first blade 46a and the second blade 46b are formed by bonding abrasive grains such as diamond and CBN (Cubic Boron Nitride) with a binder such as metal or resin. The workpiece 11 is cut by rotating the first blade 46a and the second blade 46b at high speed and cutting them into the workpiece 11 held by the chuck tables 4a and 4b.

  On the other hand, as shown in FIG. 1, the first imaging unit moving mechanism 18a and the second imaging unit moving mechanism 18b are provided with a pair of Y-axis guide rails 50 parallel to the Y-axis direction arranged on the surface side of the bridging portion 10b. Commonly prepared. On the Y-axis guide rail 50, Y-axis movement tables 52a and 52b constituting the first imaging unit moving mechanism 18a and the second imaging unit moving mechanism 18b are slidably installed.

  Nut portions having screw holes are provided on the back surfaces of the Y-axis moving tables 52a and 52b, and Y-axis ball screws 54a and 54b parallel to the Y-axis guide rail 50 are provided in the screw holes of these nut portions. Are screwed together.

  A Y-axis pulse motor 56 is connected to one end of each of the Y-axis ball screws 54a and 54b (the Y-axis pulse motor on the first imaging unit moving mechanism 18a side is not shown). When the Y axis ball screws 54 a and 54 b are rotated by the Y axis pulse motor 56, the Y axis movement tables 52 a and 52 b move in the Y axis direction along the guide rail 50.

  A first imaging unit 14a and a second imaging unit 14b are arranged below the Y-axis movement tables 52a and 52b. If the Y-axis movement tables 52a and 52b are moved as described above, the first imaging unit 14a and the second imaging unit 14b also move in the Y-axis direction.

  The first imaging unit 14a and the second imaging unit 14b each include an imaging device such as a CCD and an optical system such as a lens, and image the workpiece 11 held on the chuck tables 4a and 4b. A nozzle (not shown) for injecting air to the workpiece 11 is provided at a position close to the first imaging unit 14a and the second imaging unit 14b.

  In this cutting apparatus 2, two workpieces 11 held on the chuck tables 4a and 4b are respectively separated by a first cutting unit 12a (first blade 48a) and a second cutting unit 12b (second blade 48b). It can cut and can image with the 1st imaging unit 14a and the 2nd imaging unit 14b.

  Moreover, the cutting device 2 is a range in which the first cutting unit 12a and the second cutting unit 12b, and the first imaging unit 14a (first blade 48a) and the second imaging unit 14b (second blade 48b) do not interfere with each other. Can be moved in the Y-axis direction.

  Thus, one workpiece 11 held on the chuck table 4a or the chuck table 4b is cut by both the first cutting unit 12a (first blade 48a) and the second cutting unit 12b (second blade 48b). It is possible to take an image with both the first imaging unit 14a and the second imaging unit 14b.

  Next, the cutting method implemented with the cutting apparatus 2 is demonstrated. In the present embodiment, one workpiece 11 held on the chuck table 4a is divided into a first cutting unit 12a (first blade 48a), a second cutting unit 12b (second blade 48b), and a first imaging. A cutting method of cutting using the unit 14a and the second imaging unit 14b will be described.

  In the cutting method of the present embodiment, first, a holding step for holding the workpiece 11 on the chuck table 4a of the cutting device 2 is performed. FIG. 3 is a partial cross-sectional side view schematically showing the holding step. Note that a tape 21 is attached in advance to the back surface 11 b side of the workpiece 11, and an annular frame 23 is fixed to the outer peripheral portion of the tape 21.

  In the holding step, the tape 21 is brought into contact with the holding surface of the chuck table 4a to apply a negative pressure of the suction source. As a result, the workpiece 11 is sucked and held on the chuck table 4 a via the tape 21. At the end of the holding step, the surface 11a side of the workpiece 11 is exposed upward.

  After the holding step is completed, a cutting step is performed in which the workpiece 11 held on the chuck table 4a is cut by the first blade 48a and the second blade 48b. FIG. 4 is a partial cross-sectional side view schematically showing the cutting step.

  In the cutting step, first, the first blade 48a and the second blade 48b are aligned with the first scheduled machining line and the second scheduled machining line of the workpiece 11, respectively. Then, the first blade 48a and the second blade 48b are rotated to be cut into the workpiece 11, and the chuck table 4a, the first blade 48a and the second blade 48b are relatively moved in the X-axis direction (process feed). )

  As a result, the workpiece 11 is cut along the first scheduled machining line and the second scheduled machining line, and the first kerf 13a and the second kerf 13b are formed. In the present embodiment, the first blade 48a and the second blade 48b are cut to a depth that reaches the tape 21, and the workpiece 11 is completely cut. It is good also as a half cut which does not cut | disconnect the workpiece 11 completely.

  After the end of the cutting step, an inter-calf distance calculating step for calculating an inter-calf distance between the first kerf 13a and the second kerf 13b formed in the cutting step is performed. As described above, the first kerf 13a and the second kerf 13b are formed at the positions of the first blade 48a and the second blade 48b in the cutting step.

  That is, the kerf distance corresponds to the difference between the coordinates of the first blade 48a and the coordinates of the second blade 48b in the Y-axis direction. Therefore, as shown in FIG. 4, the cutting device 2 uses a kerf between the first kerf 13 a and the second kerf 13 b based on the positions of the first blade 48 a and the second blade 48 b (coordinates in the Y-axis direction). The distance D1 is calculated.

  Here, the coordinates of the first blade 48a and the second blade 48b in the Y-axis direction are, for example, scale reading mechanisms (not shown) attached to the guide rail 30 provided in the Y-axis moving tables 32a and 32b (see FIG. It can be detected by reading with (not shown).

  After performing the inter-calf distance calculating step, a detecting step for detecting the states of the first kerf 13a and the second kerf 13b is performed. FIG. 5 is a partial cross-sectional side view schematically showing the detection step.

  In the detection step, first, it is determined whether the first kerf 13a and the second kerf 13b can be imaged using both the first imaging unit 14a and the second imaging unit 14b. Specifically, it is determined whether the kerf distance D1 is equal to or greater than the closest distance at which the first imaging unit 14a and the second imaging unit 14b can be closest to each other.

  For example, when the inter-calf distance D1 is equal to or greater than the closest distance described above, the second imaging unit 14b can be positioned above the second kerf 13b after the first imaging unit 14a is positioned above the first kerf 13a. it can. Therefore, in this case, as shown in FIG. 5, the first imaging unit 14a images the first kerf 13a and the second imaging unit 14b images the second kerf 13b.

  In addition, before imaging the first kerf 13a with the first imaging unit 14a, air is ejected from a nozzle adjacent to the first imaging unit 14a to remove water (cutting water) and the like attached to the first kerf 13a. . Similarly, before the second kerf 13b is imaged by the second imaging unit 14b, air is ejected from a nozzle adjacent to the second imaging unit 14b to remove water (cutting water) or the like adhering to the second kerf 13b. To do.

  FIG. 6 is a diagram schematically illustrating an example of an image acquired in the detection step. 6A shows an image 31a including the first kerf 13a imaged by the first imaging unit 14a, and FIG. 6B shows the second kerf 13b imaged by the second imaging unit 14b. An included image 31b is shown. 6A and 6B show a state in which chipping 15 has occurred at the edges of the first kerf 13a and the second kerf 13b.

  As shown in FIGS. 6A and 6B, when the inter-calf distance D1 is equal to or greater than the closest distance, the image 31a including the first kerf 13a and the image 31b including the second kerf 13b; Can be acquired simultaneously using the first imaging unit 14a and the second imaging unit 14b. Therefore, in this case, the time required to detect the kerf state is shortened.

  When the images 31a and 31b are acquired, the cutting device 2 determines the kerf width Wa and the maximum chipping size Ca of the first kerf 13a and the kerf width Wb and the maximum chipping of the second kerf 13b based on the images 31a and 31b. The size Cb is calculated. Note that the method for calculating the kerf width and the maximum chipping size is arbitrary.

  On the other hand, when the distance between the kerfs is less than the closest distance described above, if the first imaging unit 14a is positioned above the first kerf, the second imaging unit 14b cannot be positioned above the second kerf. Therefore, in this case, the first kerf and the second kerf are imaged using only the first imaging unit 14a.

  FIG. 7 is a partial cross-sectional side view schematically showing another example of the cutting step, and FIG. 8 is a partial cross-sectional side view schematically showing another example of the detection step. In the cutting step of FIG. 7, the inter-calf distance D2 between the first kerf 17a and the second kerf 17b to be formed is less than the closest distance described above.

  In this case, as shown in FIG. 8, after the first kerf 17a is imaged by the first imaging unit 14a, the first imaging unit 14a and the chuck table 4a are relatively moved in the Y-axis direction, and the first imaging unit 14a. Then, the second kerf 17b is imaged.

  As described above, the first kerf 17a and the second kerf 17b are appropriately moved even when the inter-calf distance D2 is less than the closest distance by moving the first imaging unit 14a and the chuck table 4a relative to each other in the Y-axis direction. Can be imaged. After the images of the first kerf 17a and the second kerf 17b are acquired, the kerf width, chipping size, and the like are calculated.

  In the present embodiment, since the target workpiece 11 is held on the chuck table 4a, the first kerf 17a and the second kerf 17b are imaged by the first imaging unit 14a close to the chuck table 4a. However, in general, the first kerf 17a and the second kerf 17b may be imaged by one imaging unit close to the chuck table that holds the target workpiece 11.

  That is, when the workpiece 11 is held on the chuck table 4b, the first kerf 17a and the second kerf 17b are imaged by the second imaging unit 14b close to the chuck table 4b.

  As described above, in the cutting method according to the present embodiment, the distance D1 between the first kerf 13a formed by the first blade 48a and the second kerf 13b formed by the second blade 48b is such that the first imaging unit (First imaging means) 14a and second imaging unit (second imaging means) 14b, when the distance is closest to the closest distance, the first imaging unit 14a images the first kerf 13a and the second The imaging unit 14b images the second kerf 13b and detects the states of the first kerf 13a and the second kerf 13b.

  Thus, according to the cutting method according to the present embodiment, the first kerf 13a and the second kerf 13b in the first imaging unit 14a and the second imaging unit 14b according to the distance between the first kerf 13a and the second kerf 13b. Since the two kerfs 13b can be imaged simultaneously, the time required for the kerf check can be shortened and productivity can be increased as compared with the conventional method of imaging a plurality of kerfs with one imaging unit.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the cutting method for cutting the workpiece 11 held on the chuck table 4a has been described. However, the workpiece 11 held on the chuck table 4b can also be cut by the same cutting method.

  In the above embodiment, the first kerf 17a and the second kerf 17b are imaged using the first imaging unit 14a when the kerf distance D2 is less than the closest distance. The first kerf 17a and the second kerf 17b may be imaged using the second imaging unit 14b. That is, you may image the 1st kerf 17a and the 2nd kerf 17b with one image pick-up unit far from the chuck table holding the target workpiece 11.

  In the above embodiment, the second kerf 17b is imaged after the first kerf 17a is imaged. However, the first kerf 17a may be imaged after the second kerf 17b is imaged. In addition, the configurations, methods, and the like according to the above-described embodiments can be changed as appropriate without departing from the scope of the object of the present invention.

11 Workpiece 11a Front surface 11b Back surface 13a First kerf 13b Second kerf 15 Chipping 17a First kerf 17b Second kerf 21 Tape 23 Frame D1, D2 Distance between kerfs 2 Cutting device 4a, 4b Chuck table (holding means)
6a, 6b X-axis moving mechanism 8a, 8b Column 10a, 10b Bridge 12a First cutting unit 12b Second cutting unit 14a First imaging unit (first imaging means)
14b Second imaging unit (second imaging means)
16a First cutting unit moving mechanism 16b Second cutting unit moving mechanism 18a First imaging unit moving mechanism 18b Second imaging unit moving mechanism 20a, 20b X-axis guide rails 22a, 22b X-axis moving tables 24a, 24b X-axis ball screw 26a, 26b X-axis pulse motor 28a, 28b Clamp 30 Y-axis guide rail 32a, 32b Y-axis moving table 34a, 34b Y-axis ball screw 36 Y-axis pulse motor 38a, 38b Z-axis guide rail 40a, 40b Z-axis moving table 42a, 42b Z Axis pulse motor 44a, 44b Arm part 46a First blade 46b Second blade 48a, 48b Spindle 50 Y axis guide rail 52a, 52b Y axis moving table 54a, 54b Y axis ball screw 56 Y axis pulse motor

Claims (1)

Holding means for holding the workpiece, a first blade for cutting the workpiece held by the holding means, a second blade disposed facing the first blade, and held by the holding means A cutting method for cutting a workpiece with a cutting device comprising a first imaging means and a second imaging means for imaging the processed workpiece,
A holding step for holding the workpiece by holding means;
The workpiece held by the holding means is cut with a first blade to form a first kerf, and the workpiece is cut with a second blade disposed facing the first blade. A cutting step to form two calves;
A detection step for detecting a state of the first kerf and the second kerf formed in the cutting step;
After performing the cutting step and before performing the detecting step, from the position of the first blade and the second blade in the cutting step, between the kerf between the first kerf and the second kerf A calf distance calculating step for calculating a distance,
In the detection step, when the distance between the kerfs calculated in the distance calculation step between the kerfs is equal to or greater than a distance at which the first imaging unit and the second imaging unit are closest to each other, the first kerf is An image is picked up by the image pickup means and the second kerf is picked up by the second image pickup means to detect states of the first kerf and the second kerf, respectively, and the first image pickup means and the second image pickup means are the most. When the distance between the kerfs is narrower than the distance that can be approached, the first kerf and the second kerf are closer to the first kerf and the second kerf. A cutting method comprising: imaging a second kerf and detecting states of the first kerf and the second kerf, respectively.

Images