JP6498486B2 - Cutting equipment - Google Patents

Description

  The present invention relates to a cutting apparatus capable of setting up a cutting blade before cutting.

  Usually, in a cutting apparatus, setup is performed in order to adjust the cutting depth by a cutting blade. As a setup, a method is known in which an optical sensor is used to detect and set the tip position of a cutting blade in a non-contact manner. In this method, the light projecting portion and the light receiving portion of the optical sensor are opposed to each other with a gap therebetween, and the cutting blade is lowered into this gap, and the light from the light projecting portion is blocked by the tip of the cutting blade. Then, the tip position of the cutting blade is detected from the change in the amount of light received by the light receiving portion, and the cutting amount of the cutting blade relative to the wafer is corrected (corrected) based on the amount of change in the diameter of the cutting blade worn by the cutting. .

  However, in the method using the optical sensor, it is necessary to prevent the cutting water used in the cutting process by the cutting apparatus from adhering to the light projecting part and the light receiving part of the optical sensor. Furthermore, when the water droplets scattered from the cutting blade pass through the gap between the light projecting unit and the light receiving unit and the light from the light projecting unit is scattered by the water droplets, the tip position of the cutting blade is erroneously detected. As described above, in the method using the optical sensor, the optical sensor has a complicated structure in order to prevent water droplets from adhering to the light projecting part and the light receiving part during the cutting process, and it takes time to dry the cutting blade. There was a problem.

  Instead of the method using the optical sensor described above, a method is known in which the diameter of the cutting blade is calculated by image processing to set up the tip position of the cutting blade (for example, see Patent Document 1). In the method described in Patent Document 1, a dummy workpiece (workpiece) is cut from directly above with a cutting blade to form a cutting trace, and an image captured of the cutting trace is image-processed so that the diameter of the cutting blade is geometric. Is calculated. A method of detecting the height of a table using a back pressure sensor is also known in order to improve the accuracy of cutting a dummy workpiece with a cutting blade (see Patent Document 2).

JP 2002-59365 A JP 2013-41972 A

  However, in the methods described in Patent Documents 1 and 2, even if the height of the table is measured by the back pressure sensor, it is not possible to detect the tip position of the cutting blade whose diameter has been reduced due to the consumption of the cutting blade. For this reason, it was not possible to cut the dummy workpiece with an appropriate cutting depth with a cutting blade. In other words, when cutting a dummy workpiece from directly above with a cutting blade, the consumption amount of the cutting blade is predicted in order to eliminate idle swinging, and the cutting blade is cut deeper into the dummy workpiece. There was a problem that.

  The present invention has been made in view of this point, and an object of the present invention is to provide a cutting apparatus capable of calculating and setting up the diameter of the cutting blade with high accuracy while suppressing the consumption of the cutting blade.

The cutting apparatus of the present invention includes a holding table having a holding surface for holding a plate-like workpiece, a cutting means for cutting the cutting blade by cutting the cutting blade into the workpiece by rotatably mounting the cutting blade, A cutting device comprising: a cutting feed means for approaching and separating the cutting means in a direction perpendicular to the upper surface of the work piece held by the holding table; and a tip detecting means for detecting the tip of the cutting blade; An image pickup means for picking up an image of a cutting mark formed by cutting a cutting blade into an object, and a calculating means for calculating a diameter of the cutting blade from an image captured by the image pickup means. An injection port that injects air of a predetermined pressure onto one side surface of the cutting blade in a direction intersecting the side surface of the rotating cutting blade, and the cutting blade is cut and fed by the cutting feed unit. Includes a back pressure sensor for detecting a pressure change in the path from the air supply source to the ejection outlet, a tip determination unit for determining that the tip of the cutting blade with a pressure change in the back pressure sensor detects the By shielded, cut The feed means is based on the amount of wear of the cutting blade measured from the difference between the lowered position where the tip of the cutting blade is detected by the tip detecting means and the lowered position where the tip of the cutting blade is detected when the cutting blade is not consumed. Based on this, the cutting depth of the cutting blade is controlled, and the calculating means captures the cutting trace formed by cutting the cutting blade whose tip is detected by the tip detecting means into the work piece with the cutting depth , and the imaging means picks up the image. A scale that measures the length of the trace in the extending direction; and a calculator that calculates a diameter of the cutting blade from a measurement result measured by the scale.

  According to this configuration, when the air from the injection port is blocked by the cutting blade by the cutting feed of the cutting blade, the tip of the cutting blade is determined by detecting the pressure change by the back pressure sensor. Therefore, the tip of the cutting blade, that is, the amount of wear of the cutting blade due to cutting is measured with a relatively rough accuracy. Since the workpiece is cut in consideration of the amount of change in the tip position of the cutting blade, it is possible to prevent the blade from being wasted due to insufficient cutting or excessive cutting, and the depth appropriate for the workpiece. Can be formed. Therefore, the diameter of the cutting blade can be calculated with high accuracy from the length in the extending direction of the cutting trace in the imaged image and set up. Further, since the tip of the cutting blade is detected by the back pressure sensor, it is not affected by cutting water or water droplets scattered from the cutting blade during the cutting process. Therefore, the tip of the cutting blade can be detected easily and in a short time.

  According to the present invention, the workpiece is cut after the tip position of the cutting blade is measured with rough accuracy by the back pressure sensor, and the diameter of the cutting blade is calculated by image processing of the captured image of the cutting trace. Therefore, the cutting blade diameter can be calculated and set up with high accuracy while suppressing the consumption of the cutting blade.

It is a perspective view of the cutting device concerning this embodiment. It is a schematic diagram of the front-end | tip detection means and calculation means which concern on this Embodiment. It is a figure which shows an example of the front-end | tip detection process of the cutting blade which concerns on this Embodiment. It is a figure which shows an example of the diameter calculation process of the cutting blade which concerns on this Embodiment. It is a figure which shows an example of the image process of the captured image which concerns on this Embodiment.

  Hereinafter, the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a cutting apparatus according to the present embodiment. Note that the cutting apparatus according to the present embodiment is not limited to the configuration shown in FIG. The present invention is applicable to any cutting apparatus as long as it has a cutting blade setup function.

  As shown in FIG. 1, the cutting apparatus 1 is configured to cut the wafer W <b> 1 by relatively moving the wafer W <b> 1 held on the chuck table 10 and the cutting means 11. The wafer W1 is carried into the cutting apparatus 1 while being supported by the ring frame F via the dicing tape T. The wafer W1 may be a semiconductor wafer such as silicon or gallium arsenide, or may be a ceramic, glass, or sapphire optical device wafer. In addition to a circular wafer, a rectangular package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) may be used.

  On the base 12 of the cutting apparatus 1, a cutting feed means 13 for cutting and feeding the chuck table 10 in the X direction is provided. The cutting feed means 13 has a pair of guide rails 14 arranged on the base 12 and parallel to the X direction, and a motor-driven X-axis table 15 slidably installed on the pair of guide rails 14. Yes. A nut portion (not shown) is formed on the back side of the X-axis table 15, and a ball screw 16 is screwed into the nut portion. The chuck motor 10 is cut and fed in the X direction along the pair of guide rails 14 when the drive motor 17 connected to one end of the ball screw 16 is rotationally driven.

  A chuck table 10 that holds the wafer W <b> 1 is provided on the top of the X-axis table 15 so as to be rotatable about the Z-axis. The chuck table 10 has a holding surface (not shown) made of a porous ceramic material, and the wafer W1 is sucked and held by the negative pressure generated on the holding surface. Around the chuck table 10, four air-driven clamp portions 18 are provided, and the ring frame F of the wafer W1 is clamped and fixed from four directions by each clamp portion 18. On the upper surface of the base 12, a gate-shaped standing wall portion 20 is provided so as to straddle the movement path of the chuck table 10.

  The upright wall portion 20 is provided with an index feeding means 21 for index feeding the cutting means 11 in the Y direction and a cutting feed means 22 for cutting and feeding the cutting means 11 in the Z direction. The index feeding means 21 has a pair of guide rails 23 arranged in front of the standing wall portion 20 and parallel to the Y direction, and a Y-axis table 24 slidably installed on the pair of guide rails 23. The cutting feed means 22 has a pair of guide rails 25 arranged on the Y-axis table 24 and parallel to the Z direction, and a Z-axis table 26 slidably installed on the pair of guide rails 25. A cutting means 11 for cutting the wafer W <b> 1 is provided below the Z-axis table 26.

  Nut portions are formed on the back sides of the Y-axis table 24 and the Z-axis table 26, and ball screws 27 and 28 are screwed into these nut portions. Drive motors 29 and 30 are connected to one end portions of a ball screw 27 for the Y-axis table 24 and a ball screw 28 for the Z-axis table 26, respectively. By rotating the respective ball screws 27 and 28 by the drive motors 29 and 30, the cutting means 11 is index-fed along the guide rail 23 in the Y direction orthogonal to the X direction, and the cutting means 11 is guided by the guide rail 25. Are cut and fed in the Z direction approaching and separating from the wafer W1.

  The cutting means 11 is configured by rotatably mounting a cutting blade 40 (see FIG. 2) on the tip of a spindle 32 (see FIG. 2) protruding from the housing 31. The cutting blade 40 is formed into a disk shape by, for example, hardening diamond abrasive grains with a resin bond. The housing 31 of the cutting means 11 is provided with an image pickup means 50 for picking up the upper surface of the wafer W1, and the cutting blade 40 is aligned with the wafer W1 based on the image picked up by the image pickup means 50. In the cutting means 11, the wafer W <b> 1 is cut along the planned dividing line by the cutting blade 40 while the cutting water is being jetted, so that each device is divided.

  Moreover, in the cutting apparatus 1, the setup which sets the origin position of the cutting feed direction of the cutting blade 40 by the diameter calculation of the cutting blade 40 (refer FIG. 2) is implemented before cutting of the wafer W1. A sub-chuck table 33 is disposed around the chuck table 10, and a dummy workpiece (workpiece) W2 is formed as a workpiece to be cut when calculating the diameter on the holding surface 34 (see FIG. 4) of the sub-chuck table 33. Is held. The dummy workpiece W2 is used as a sample for calculating the diameter of the cutting blade 40, and is formed in a flat plate shape whose front surface and back surface are parallel. The dummy workpiece W2 may be formed of the same material as the wafer W1, or may be formed of a different material.

  In this case, the dummy workpiece W2 is cut from directly above by the cutting blade 40, and the cutting trace on the dummy workpiece W2 is imaged by the above-described alignment imaging means 50. The captured image of the cutting trace is subjected to image processing, and the diameter of the cutting blade 40 is calculated by the calculating means 60 (see FIG. 2). At the time of diameter calculation by this image processing, the consumption of the cutting blade 40 is predicted and the dummy workpiece W2 is cut into the cutting blade 40. When the cutting blade 40 is less consumed than predicted, the dummy workpiece W2 is deepened by the cutting blade 40. It will be cut. For this reason, there is a problem that the cutting blade 40 is wasted when the dummy workpiece W2 is cut.

  Therefore, the cutting apparatus 1 according to the present embodiment is configured to perform the tip position detection processing of the cutting blade 40 before the diameter calculation processing of the cutting blade 40 by image processing. Thereby, the cutting depth of the cutting blade 40 with respect to the dummy workpiece W2 can be appropriately adjusted by measuring the amount of wear of the cutting blade 40 roughly in the detection processing of the tip position of the cutting blade 40. The two-step process of detecting the tip position of the cutting blade 40 and calculating the diameter of the cutting blade 40 eliminates excessive cutting of the cutting blade 40 with respect to the dummy workpiece W2 and enables calculation of the diameter with reduced consumption of the cutting blade 40. Yes.

  Usually, an optical sensor is used for the detection process of the tip position of the cutting blade 40. However, since the cutting water adheres to the sensor surface or the sensor reacts to water droplets scattered from the cutting blade 40, the sensor is operated once. In the detection process, sufficient reliability cannot be obtained. For this reason, when using an optical sensor, the detection process of the front-end | tip position of the cutting blade 40 must be implemented in multiple times. Here, when the present inventor performs back pressure type tip detection using the back pressure sensor 71 (see FIG. 2) instead of the optical sensor, it is affected by cutting water and water droplets scattered from the cutting blade 40. It was discovered that the tip position of the cutting blade 40 can be detected.

  In general, the back pressure sensor 71 is used for measuring the height of the table, and is used by being arranged above the table. The back pressure sensor 71 that has not been used for detecting the tip position of the cutting blade 40 is used instead of the optical sensor, so that the number of times of processing for detecting the tip position of the cutting blade 40 is reduced. Thus, in the present embodiment, the back pressure type tip detecting means 70 (see FIG. 2) for detecting the tip of the cutting blade 40 is provided, and the calculation unit 62 (see FIG. 2) is used after the tip of the cutting blade 40 is detected. Setup is performed by calculating the diameter of the cutting blade 40.

  Hereinafter, with reference to FIG. 2, the tip detection unit and the calculation unit according to the present embodiment will be described in detail. FIG. 2 is a schematic diagram of the tip detection unit and the calculation unit according to the present embodiment. In FIG. 2, for convenience of explanation, the dummy work on the sub-chuck table is omitted.

  As shown in FIG. 2, the tip detecting means 70 detects the tip of the cutting blade 40 by blocking the nozzle 73 at the tip of the cutting blade 40 in a state where air is jetted from the nozzle 73 of the nozzle 72. Is configured to do. When detecting the tip of the cutting blade 40, the nozzle 72 directs the injection port 73 to the side so as to inject air of a predetermined pressure onto one side surface of the cutting blade 40 in a direction intersecting the side surface of the cutting blade 40. It is arranged on the sub chuck table 33 in a state. The direction intersecting the side surface of the cutting blade 40 may be not only the direction orthogonal to the side surface of the cutting blade 40 but also the direction intersecting obliquely with the side surface of the cutting blade 40.

  The tip detection means 70 includes a back pressure sensor 71 that detects a pressure change in the path 75 from the air supply source 74 to the nozzle 72, and a tip change of the cutting blade 40 based on the pressure change detected by the back pressure sensor 71. And a leading edge determination unit 76 is provided. The back pressure sensor 71 detects a pressure change in the path 75 when the injection port 73 is shielded by the cutting blade 40 cut and fed by the cutting feed means 22, and outputs a detection result to the tip determination unit 76. The tip determination unit 76 determines the tip position from the cutting depth of the cutting blade 40 when the pressure change in the path 75 becomes a predetermined value or more. In accordance with the tip position of the cutting blade 40, the cutting amount when calculating the diameter of the cutting blade 40 is corrected.

  A cutting blade 80 (see FIG. 4) having a predetermined depth is formed on the dummy workpiece W2 (see FIG. 4) by the cutting blade 40 whose tip is detected by the tip detecting means 70. The cutting trace 80 of the dummy workpiece W2 is imaged by the imaging unit 50 provided in the cutting unit 11, and the captured image is output from the imaging unit 50 to the calculation unit 60. The calculating means 60 is configured to measure the length of the captured image of the cutting trace 80 in the extending direction with the scale 61 and calculate the diameter of the cutting blade 40 with the calculating unit 62 from the measurement result of the scale 61. The details of the length measurement of the cutting mark 80 by the scale 61 and the calculation of the diameter of the cutting blade 40 by the calculation unit 62 will be described later.

  Note that the tip determination unit 76 and the calculation unit 60 are configured by a processor, a memory, and the like that execute various processes. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. The memory stores a tip detection processing program for the cutting blade 40, a diameter calculation program for the cutting blade 40, and a setup program. Moreover, it is preferable that the cutting blade 40 has such a rigidity that it is not bent by the injection of air from the injection port 73 of the nozzle 72.

  With reference to FIGS. 3 to 5, the cutting blade tip detection process and the cutting blade diameter calculation process will be described in detail. FIG. 3 is a diagram showing an example of the cutting blade tip detection process according to the present embodiment. FIG. 4 is a diagram illustrating an example of a diameter calculation process of the cutting blade according to the present embodiment. FIG. 5 is a diagram illustrating an example of image processing of a captured image according to the present embodiment. In FIG. 3, it is assumed that the cutting blade has already been consumed by cutting, and the tip of the cutting blade before consumption is indicated by a virtual line.

  First, the cutting blade tip detection process will be described. As shown in FIG. 3A, a nozzle 72 is provided on the sub chuck table 33, and air having a predetermined pressure is ejected from an ejection port 73 of the nozzle 72 toward the side. Further, the cutting blade 40 whose tip is consumed during the cutting process is positioned directly above the air injection area A by the nozzle 72. Then, in a state where the cutting blade 40 is rotated, the cutting blade 40 is cut and fed in the Z-axis direction from the initial position P1 toward the air injection region A. The air injection region A is a region where air from the injection port 73 of the nozzle 72 is injected by the cutting blade 40, and is not limited to the vicinity of the injection port 73, and a pressure change can be detected by the back pressure sensor 71. Includes a range.

  As shown in FIG. 3B, when the cutting blade 40 is lowered toward the injection region A, the cutting blade 40 is brought close to the injection port 73 of the nozzle 72. At this time, since the tip of the cutting blade 40 has already been consumed by the cutting process, even if the cutting blade 40 is cut and fed to the lowered position P <b> 2 where the injection port 73 can be shielded when the cutting blade 40 is not consumed, the cutting blade 40 ejects the injection port 73. Is not shielded. The cutting blade 40 is cut and fed from the lowered position P2 to the lower lowered position P3, whereby the injection port 73 is shielded by the cutting blade 40, and the tip position of the cutting blade 40 is detected.

  In this case, when the cutting blade 40 is at the initial position P1 and the lowered position P2, the tip of the cutting blade 40 is located above the injection port 73 of the nozzle 72, so that air is blocked from the injection port 73 to the cutting blade 40. I can't. For this reason, the pressure change in the path 75 detected by the back pressure sensor 71 is small, and the tip determination unit 76 determines that there is no tip of the cutting blade 40. When the cutting blade 40 is lowered to the lowered position P3, air is blocked from the injection port 73 by the tip of the cutting blade 40, and therefore the pressure change in the path 75 detected by the back pressure sensor 71 is large. Thus, it is determined that the tip of the cutting blade 40 is present.

  Then, the consumption amount Δa of the cutting blade 40 is coarsened from the difference between the lowered position P3 where the tip of the cutting blade 40 is detected and the lowered position P2 where the tip of the cutting blade 40 is detected when the cutting blade 40 is not consumed. Measured. The consumption amount Δa of the cutting blade 40 is used as a correction amount for the cutting feed of the cutting blade 40. Accordingly, the cutting feed of the cutting blade 40 can be accurately controlled in consideration of the consumption amount Δa of the cutting blade 40. Further, the configuration of the tip detection means 70 can be simplified without being affected by the scattering of cutting water or water droplets from the cutting blade 40 during cutting.

  Next, the diameter calculation process of the cutting blade will be described. As shown in FIG. 4A, the dummy workpiece W2 is held on the holding surface 34 of the sub chuck table 33, and the cutting blade 40 is cut and fed in a rotating state. The cutting blade 40 is perpendicular to the upper surface of the dummy workpiece W2. Cut from the direction. As a result, a linear cutting mark 80 is formed at a predetermined depth on the upper surface 35 of the dummy workpiece W2. At this time, the cutting depth of the cutting blade 40 is controlled based on the amount of consumption Δa of the cutting blade 40, so that there is no idling during cutting, and wasteful consumption of the cutting blade 40 due to excessive cutting is suppressed. it can.

  As shown in FIG. 4B, when the cutting trace 80 is formed on the dummy workpiece W2, the imaging unit 50 is moved directly above the dummy workpiece W2, and the cutting trace 80 of the dummy workpiece W2 is imaged by the imaging unit 50. The captured image of the cutting trace 80 is output to the scale 61 of the calculating means 60, and the scale 61 measures the length of the cutting trace 80 in the extending direction from the captured image. In this case, edge detection processing is performed on the captured image, and the length L (see FIG. 5) in the extending direction of the cutting trace 80 is measured from the number of pixels in the X-axis direction constituting the cutting trace 80 in the scale 61. The measurement result of the scale 61 is output to the calculation unit 62, and the calculation unit 62 calculates the diameter of the cutting blade 40 from the measurement result of the scale 61.

As shown in FIG. 5, in the calculation unit 62 (see FIG. 4), the dummy workpiece W <b> 2 is calculated from the length L in the extending direction of the cutting trace 80 and the axis of the cutting blade 40 using, for example, the following equation (1). The diameter (2r) of the cutting blade 40 is calculated from the distance H to the upper surface 35. The distance H at this time is a value corrected by the consumption amount Δa of the cutting blade 40 detected by the tip detection means 70 (see FIG. 2), and is set to an appropriate height distance from the upper surface of the dummy workpiece W2. Yes.
(1)
2r = 2 (H ² + (L / 2) ² ) ^1/2
When the diameter of the cutting blade 40 is calculated, the cutting blade 40 is set up with high accuracy.

  As described above, according to the cutting device 1 according to the present embodiment, when the air from the injection port 73 is shielded by the cutting blade 40 by the cutting feed of the cutting blade 40, the pressure change is detected by the back pressure sensor 71. Thus, the tip of the cutting blade 40 is determined. Therefore, the amount of wear of the cutting blade 40 due to the cutting is measured with a relatively rough accuracy. Since the dummy workpiece W2 is cut in consideration of the amount of change in the tip position of the cutting blade 40, it is possible to form the cutting trace 80 with an appropriate depth in the dummy workpiece W2 due to the idling or excessive cutting with respect to the dummy workpiece W2. Therefore, the diameter of the cutting blade 40 can be calculated and set up with high accuracy from the length in the extending direction of the cut mark 80 in the captured image. Further, since the tip of the cutting blade 40 is detected by the back pressure sensor 71, it is not affected by cutting water or water droplets scattered from the cutting blade 40 during the cutting process.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the diameter of the cutting blade 40 is calculated using the dummy workpiece W2 held on the sub-chuck table 33. However, the present invention is not limited to this configuration. For example, the diameter of the cutting blade 40 may be calculated using a wafer held on the chuck table 10.

  In the above-described embodiment, the diameter of the cutting blade 40 of the cutting device 1 that divides the wafer W1 is calculated. However, the present invention is not limited to this configuration. The diameter of the cutting blade 40 of the cutting device for edge trimming may be calculated. Since the cutting blade 40 for edge trimming is formed to be relatively thick, the cutting blade 40 is not bent by the air from the injection port 73 of the nozzle 72.

  In the above-described embodiment, the tip determination unit 76 is configured to determine the tip position of the cutting blade 40 when the pressure change in the path 75 from the air supply source 74 to the nozzle 72 becomes equal to or greater than a predetermined value. However, it is not limited to this configuration. The tip determination unit 76 compares the pressure when the nozzle 73 of the nozzle 72 is not shielded by the cutting blade 40 and the pressure when the nozzle 73 of the nozzle 72 is shielded by the cutting blade 40. The tip of the cutting blade 40 may be detected.

  In the above-described embodiment, the configuration is such that the cutting mark 80 of the dummy workpiece W2 is imaged by the alignment imaging means 50, but the present invention is not limited to this configuration. The cutting mark 80 of the dummy workpiece W2 may be imaged using an imaging unit 50 that is separate from the imaging unit for alignment.

  In the above-described embodiment, the cutting blade 40 is cut and fed in the direction in which the cutting blade 40 approaches and separates from the wafer W1 by the cutting feed means 22. However, the present invention is not limited to this configuration. A configuration in which the wafer W1 is cut and fed in the direction of approaching and separating from the cutting blade 40 by the cutting feed means 22 may be employed.

  Further, in the above-described embodiment, the air is jetted from the jet port 73 of the nozzle 72 in a direction orthogonal to the side surface of the cutting blade 40, but the configuration is not limited thereto. The injection port 73 of the nozzle 72 may be configured to inject air from an oblique direction with respect to the side surface of the cutting blade 40.

  In the above-described embodiment, the pressure change at the intermediate position of the path 75 from the air supply source 74 to the injection port 73 is detected. However, the present invention is not limited to this configuration. The back pressure sensor 71 only needs to be able to detect a pressure change in the path 75 from the air supply source 74 to the injection port 73. For example, the back pressure sensor 71 may detect a pressure change in the vicinity of the injection port 73.

  In the above-described embodiment, the length is measured from the number of pixels in the extending direction of the cutting mark 80 by the scale 61. However, the present invention is not limited to this configuration. The scale 61 may be configured in any way as long as it can measure the length of the cutting trace 80 in the extending direction.

  In the above-described embodiment, the calculation unit 62 calculates the diameter of the cutting blade 40 from the length of the cutting mark 80 according to the above equation (1). However, the present invention is not limited to this configuration. The calculation means 60 only needs to be able to calculate the diameter of the cutting blade 40 from the length of the cutting mark 80, and uses a table in which the length of the cutting mark 80 and the diameter of the cutting blade 40 are associated with each other. May be calculated.

  As described above, the present invention has an effect that it is possible to set up a reference position for cutting of a cutting device, and is particularly useful for a cutting device that etch trims the outer peripheral surface of a wafer.

DESCRIPTION OF SYMBOLS 1 Cutting device 11 Cutting means 22 Cutting feed means 33 Sub chuck table (holding table)
34 Holding surface 40 Cutting blade 50 Imaging means 60 Calculation means 61 Scale 62 Calculation part 70 Tip detection means 71 Back pressure sensor 73 Injection port 74 Air supply source 75 Path 76 Tip judgment part 80 Cutting mark W2 Dummy work (workpiece)

Claims (1)

A holding table having a holding surface for holding a plate-like workpiece, a cutting means for rotatably mounting a cutting blade and cutting the cutting blade into the workpiece, and the holding table hold A cutting device comprising: cutting feed means for approaching and separating the cutting means in a direction perpendicular to the upper surface of the workpiece,
From a tip detection means for detecting the tip of the cutting blade, an imaging means for imaging a cutting trace formed by cutting the cutting blade into a workpiece, and an imaging image obtained by imaging the cutting trace by the imaging means Calculating means for calculating the diameter of the cutting blade,
The tip detecting means is
An injection port for injecting air of a predetermined pressure to one side surface of the cutting blade in a direction intersecting the side surface of the rotating cutting blade, and the cutting means is incised and fed by the incision feeding means. A back pressure sensor for detecting a pressure change in the path from the air supply source to the injection port by shielding the mouth, and a tip judgment unit for judging the tip of the cutting blade by the pressure change detected by the back pressure sensor; With
The cutting feed means is measured from a difference between a lowered position where the tip of the cutting blade is detected by the tip detecting means and a lowered position where the tip of the cutting blade is detected when the cutting blade is not consumed. The cutting depth of the cutting blade is controlled based on the consumption amount of the cutting blade,
The calculating means is:
A cutting trace formed by cutting the cutting blade whose tip is detected by the tip detection means into the workpiece with the cutting depth is imaged by the imaging means, and the length of the cutting trace in the extending direction is measured. A cutting apparatus comprising: a scale; and a calculation unit that calculates a diameter of the cutting blade from a measurement result measured by the scale.

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