JP7610396B2 - Cutting Equipment - Google Patents

Description

The present invention relates to a cutting device.

A known cutting process is to form grooves with a cutting blade in various plate-shaped workpieces such as semiconductor wafers and resin substrates to form chips for multiple devices or to remove layers of devices created on streets (planned division lines). The grooves are machined under pre-determined processing conditions so that they are formed in the center of the streets with a notch of a specified size or less.

However, due to individual differences in the workpiece, clogging of the cutting blade, slight expansion and contraction of the axis of the cutting device, etc., the position of the cutting groove may shift from the center of the street (off-center), and large chipping may occur suddenly. For this reason, cutting devices are equipped with an automatic inspection function called kerf check, which automatically photographs the cutting groove and observes its condition. In the kerf check, the street of the workpiece is photographed during processing, and the edges of the cutting groove in particular are detected by image processing. This automatically detects the width of the cutting groove, the off-center of the cutting groove, and the size and frequency of chipping that has occurred in the cutting groove, and compares it with a preset threshold value to automatically check for abnormalities (see, for example, Patent Document 1).

Patent No. 6029271

In the captured image processed by Kerf Check, the cutting grooves are displayed dark and the areas of the streets where no cutting grooves are formed are displayed bright. However, if the cutting grooves are shallow and thick, the center of the cutting groove is also likely to be displayed bright due to the lighting, which may lead to the mistaken recognition that two cutting grooves have been formed. In addition, if the TEG (Test Element Group) formed on the street is displayed dark, the TEG may be mistakenly recognized as chipping. Therefore, a mask can be set in the center or on both sides of the cutting groove to prevent misrecognition. However, if the size of the cutting blade is changed, for example to a thinner blade, and the mask setting is forgotten to be changed, the cutting groove may be hidden by the mask in the center, resulting in an error in which the cutting groove cannot be found.

The present invention was made in consideration of such problems, and its purpose is to provide a cutting device that can prevent erroneous detection of cutting grooves due to forgetting to change the mask settings.

In order to solve the above-mentioned problems and achieve the object, the cutting device of the present invention is a cutting device including a chuck table for holding a workpiece, and a cutting unit for forming a cut groove in the workpiece held on the chuck table with a cutting blade attached to a spindle, the cutting device including an imaging unit for imaging the cut groove formed in the workpiece during processing to obtain a captured image, a memory unit for storing cutting conditions for cutting the workpiece, confirmation items for confirming the quality of the cut groove and tolerances for the confirmation items, and information on the blade thickness of the cutting blade, an image processing unit for detecting the cut groove from the captured image, a judgment unit for judging whether or not the plurality of confirmation items have exceeded their respective tolerances based on the cut groove detected by the image processing unit, and an alarm unit for notifying the result of the judgment by the judgment unit, wherein the image processing unit has a mask setting unit for masking an area inside or outside both banks of the cut groove as an area outside the detection target of the cut groove when detecting the cut groove from the captured image, and the mask setting unit calculates and sets the area corresponding to the blade thickness of the cutting blade stored in the memory unit . The memory unit may further store the difference between the blade thickness of the cutting blade and the width of the inner region, and the mask setting unit may calculate the width based on the blade thickness of the cutting blade and the difference, and set the inner region.

The present invention can prevent erroneous detection of cutting grooves due to forgetting to change the mask settings.

FIG. 1 is a perspective view showing an example of the configuration of a cutting device according to an embodiment. FIG. 2 is a perspective view showing an example of a workpiece to be processed by the cutting device of FIG. FIG. 3 is a diagram showing an example of condition data stored in the storage unit of FIG. FIG. 4 is a diagram showing an example of mask setting data stored in the storage unit of FIG. FIG. 5 is a cross-sectional view showing an example of the cutting operation of the cutting device of FIG. FIG. 6 is a cross-sectional view showing an example of an imaging operation of the cutting device of FIG. FIG. 7 is a diagram showing an example of a display screen of the result of the kerf check in the cutting device of FIG. FIG. 8 is a diagram showing another example of the result display screen of the kerf check in the cutting device of FIG.

The following describes in detail the form (embodiment) for carrying out the present invention with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

[Embodiment]
A cutting device 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration example of the cutting device 1 according to the embodiment. FIG. 2 is a perspective view showing an example of a workpiece 100 to be processed by the cutting device 1 of FIG. 1. FIG. 3 is a diagram showing an example of condition data 300 stored in the storage unit 41 of FIG. 1. FIG. 4 is a diagram showing an example of mask setting data 350 stored in the storage unit 41 of FIG. 1. As shown in FIG. 1, the cutting device 1 according to the embodiment includes a chuck table 10, a cutting unit 20, an imaging unit 30, a control unit 40, a notification unit 50, and a cassette mounting table 60.

In this embodiment, the workpiece 100 to be cut by the cutting device 1 is, as shown in FIG. 2, a disk-shaped semiconductor wafer or an optical device wafer made of a base material such as silicon, sapphire, silicon carbide (SiC), or gallium arsenide. The workpiece 100 has a chip-sized device 103 formed in an area partitioned by a plurality of streets (planned division lines) 102 formed in a lattice shape on a flat surface 101. In this embodiment, the workpiece 100 has an adhesive tape 105 attached to a back surface 104 on the back side of the front surface 101, and an annular frame 106 attached to the outer edge of the adhesive tape 105, but this is not limited to this in the present invention. In addition, the workpiece 100 in the present invention may be a rectangular package substrate, a ceramic plate, a glass plate, or the like having a plurality of devices sealed with resin. In this embodiment, the workpiece 100 has a TEG (Test Element Group) (not shown) made of metal formed in the outer widthwise region of the street 102, but the present invention is not limited to this, and a TEG may not be formed, and other dummy patterns may be formed in a similar region.

The chuck table 10 includes a disk-shaped frame body with a recess formed therein and a disk-shaped suction part fitted into the recess. The suction part of the chuck table 10 is formed of a porous ceramic or the like with a large number of porous holes, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The upper surface of the suction part of the chuck table 10 is a holding surface 11 on which the workpiece 100 is placed and which suction-holds the placed workpiece 100. In this embodiment, the holding surface 11 is a surface on which the workpiece 100 is placed with the front surface 101 facing upward, and suction-holds the placed workpiece 100 from the back surface 104 side via an adhesive tape 105. The holding surface 11 and the upper surface of the frame body of the chuck table 10 are arranged on the same plane and are formed parallel to the XY plane, which is a horizontal plane. The chuck table 10 is movable in the X-axis direction, which is one horizontal direction, by an X-axis moving unit (not shown), and is rotatable around the Z-axis, which is vertical and perpendicular to the XY plane, by a rotary drive source (not shown).

As shown in FIG. 1, the cutting unit 20 has a cutting blade 21 and a spindle 22. The cutting blade 21 is attached to the tip of the spindle 22, and is rotated around an axis parallel to the Y direction, which is another horizontal direction and perpendicular to the X direction, to cut the workpiece 100 held on the chuck table 10. The cutting unit 20 is provided so as to be movable in the Y-axis direction by a Y-axis moving unit relative to the workpiece 100 held on the chuck table 10, and is also provided so as to be movable in the Z-axis direction by a Z-axis moving unit (not shown). The cutting device 1 is a so-called facing dual type cutting device, in which the cutting unit 20 has two cutting blades 21 facing each other in the Y-axis direction, that is, a two-spindle dicer.

The cutting blade 21 is made of abrasive grains such as diamond or CBN (Cubic Boron Nitride) and a bonding material such as metal or resin, and has an annular cutting edge 21-1 (see Figures 5 and 6) formed to a specified thickness (blade thickness 21-2 (see Figures 5 and 6)). As the cutting blade 21 cuts, the cutting edge 21-1 wears down, causing it to self-sharpen, and a certain level of sharpness is always maintained.

In this embodiment, the cutting unit 20 has a mechanism for acquiring information on the type of the cutting blade 21 attached to the tip of the spindle 22. The cutting unit 20 may acquire information on the type of the cutting blade 21 attached to the tip of the spindle 22, for example, by reading an identifier such as a barcode attached to the inner peripheral area of the cutting edge 21-1 of the cutting blade 21 attached to the tip of the spindle 22 with a specified reader, or may acquire information on the type of the cutting blade 21 to be newly attached when changing the cutting blade 21, by reading an identifier attached to a case that contains the newly attached cutting blade 21 with a specified reader. In addition, in response to receiving an input of the type of the cutting blade 21 from an operator or the like, the cutting blade 21 attached to the tip of the spindle 22 may be changed to the corresponding type. The cutting unit 20 outputs the acquired information on the type of the cutting blade 21 to the control unit 40.

The imaging unit 30 includes an imaging element that captures an image of the surface 101, including the streets 102, of the workpiece 100 before cutting, and the cutting grooves 200 (see Figures 5 and 6) formed in the workpiece 100 after cutting. The imaging element is, for example, a CCD (Charge-Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element. In this embodiment, the imaging unit 30 is fixed to the cutting unit 20 so as to move integrally with the cutting unit 20.

The imaging unit 30 captures an image of the workpiece 100 before cutting held on the chuck table 10, obtains an image for performing alignment to align the workpiece 100 and the cutting blade 21, and outputs the obtained image to the control unit 40. The imaging unit 30 also captures an image of the workpiece 100 after cutting held on the chuck table 10, obtains captured images 401, 402 (see Figures 7 and 8) for performing a so-called kerf check to automatically check the quality of the cut groove 200 formed by cutting the workpiece 100, such as whether the cut groove 200 is contained within the street 102 and whether any large chipping has occurred, and outputs the obtained captured images 401, 402 to the control unit 40. Note that the captured images captured by the imaging unit 30 and output to the control unit 40 are not limited to the captured images 401, 402 shown in Figures 7 and 8.

The control unit 40 controls the operation of each component of the cutting device 1 to cause the cutting device 1 to perform cutting processing of the workpiece 100. As shown in FIG. 1, the control unit 40 includes a storage unit 41, an image processing unit 42, and a judgment unit 43. As shown in FIG. 3, the storage unit 41 stores, as condition data 300, the cutting conditions under which the cutting device 1 cuts the workpiece 100, the check items in the kerf check and the tolerances that define the range for judging whether the check items pass or fail, and information on the type of the cutting blade 21, including information on the blade thickness 21-2 of the cutting blade 21, in association with each other. The storage unit 41 stores one or more condition data 300 for each blade thickness 21-2 of the cutting blade 21. The condition data 300 is data used by the control unit 40 when controlling the cutting device 1 to perform cutting processing of the workpiece 100 or when performing a kerf check, in accordance with the blade thickness 21-2 of the cutting blade 21.

As shown in FIG. 3, the memory unit 41 stores the cutting conditions in the condition data 300 by comparing the items of the cutting conditions with the numerical values and contents of the items of the cutting conditions. Here, in the example shown in FIG. 3, the items of the cutting conditions in the condition data 300 stored in the memory unit 41 include items of conditions related to the workpiece 100 such as the shape of the workpiece 100, the outer diameter of the workpiece 100, the thickness of the workpiece 100, the width 110 of the street 102 formed in the workpiece 100 (see FIG. 7 and FIG. 8), the index amount indicating the distance between adjacent streets 102, and items of conditions related to the cutting process such as the number of rotations per unit time (rotation speed) of the spindle 22 that rotates the cutting blade 21, the processing feed rate, the cutting depth, the cutting order of the streets 102, etc. The shape of the workpiece 100 indicates whether the workpiece 100 is disc-shaped or rectangular, etc. The machining feed speed is the speed at which the cutting blade 21 of the cutting unit 20 moves in the machining feed direction (X-axis direction in FIG. 1) relative to the workpiece 100 on the chuck table 10. The cutting depth is the position (depth) of the cutting blade 21 of the cutting unit 20 relative to the workpiece 100 on the chuck table 10 in the cutting depth direction (Z-axis direction in FIG. 1) during cutting processing, and determines the depth of the cutting groove 200 to be formed.

As shown in FIG. 3, the memory unit 41 stores the check items in the kerf check and the tolerances that define the ranges for judging the pass/fail of the check items in the condition data 300 in a contrasting manner. Here, the check items in the kerf check of the condition data 300 stored in the memory unit 41 include, in the example shown in FIG. 3, the off-center 202 (see FIG. 8), the kerf width Max 203 (see FIG. 8), the kerf width Min 204 (see FIG. 8), the chipping width 205 (see FIG. 8) from the kerf center 201 (see FIG. 8), and the Max chipping width 206 (see FIG. 8) from the kerf end. The off-center 202 is the value of the widthwise deviation of the kerf center 201, which is the center line that represents the center position of the cutting groove 200 in the width direction, from the center line 111 (see FIG. 8) of the street 102. The kerf width Max 203 and the kerf width Min 204 are the maximum and minimum values of the distance (spacing) between both ends 220 of the cut groove 200 in the area checked by the kerf check (within the photographed images 401 and 402). The chipping width 205 from the kerf center 201 is the distance between the end of the largest chipping in the width direction in the photographed images 401 and 402 and the center of the width direction of the cut groove 200. The max chipping width 206 from the kerf end is the distance between the end of the largest chipping in the width direction in the photographed images 401 and 402 and the end of the cut groove 200. The tolerance is a threshold value for the judgment unit 43 to judge whether each check item is normal or abnormal.

As shown in FIG. 3, the memory unit 41 stores information on the type of cutting blade 21 in the condition data 300 by correlating the item of cutting blade 21 with the numerical value and content of the item of cutting blade 21. Here, in the example shown in FIG. 3, the items of information on cutting blade 21 in the condition data 300 stored in the memory unit 41 include the type of cutting blade 21, the material of cutting edge 21-1 of cutting blade 21, and the blade thickness 21-2 of cutting edge 21-1 of cutting blade 21. The type of cutting blade 21 indicates whether cutting blade 21 is a hub blade having a hub or a hubless blade having no hub. The material of cutting edge 21-1 of cutting blade 21 includes the material of the abrasive grains and the material of the bond material.

The storage unit 41 also stores various data required when the image processing unit 42 performs the image processing described below, such as data on brightness thresholds and reference values that the image processing unit 42 uses when detecting the cutting groove 200 based on the captured images 401 and 402, layout data and data on various image elements that the image processing unit 42 uses to generate the result display screens 501 and 502, etc.

As shown in Fig. 4, the memory unit 41 stores information on the width 421 (see Figs. 7 and 8) of the inner mask 411 (see Figs. 7 and 8) and the separation width 422 (see Figs. 7 and 8) of the pair of outer masks 412 (see Figs. 7 and 8) set by the mask setting unit 44 of the image processing unit 42 described later in accordance with the blade thickness 21-2 of the cutting blade 21 as mask setting data 350. As shown in Fig. 4, the memory unit 41 stores the width 421 of the inner mask 411 and the separation width 422 of the pair of outer masks 412 in the mask setting data 350 as the difference (relative value) from the blade thickness 21-2 of the cutting edge 21-1 of the cutting blade 21 used when forming the cutting groove 200 to be checked for the kerf. Here, in the example shown in FIG. 4, in the mask setting data 350, a negative value shown in the column to the right of the mask (inner) representing the width 421 of the inner mask 411 indicates that it is narrower than the blade thickness 21-2 of the cutting blade 21, and a positive value shown in the column to the right of the mask (outer) representing the separation width 422 of the pair of outer masks 412 indicates that it is wider than the blade thickness 21-2 of the cutting blade 21. The mask setting data 350 is data that the mask setting unit 44 uses when setting the mask.

The inner mask 411 and the pair of outer masks 412 are both information processing masks that are set by the mask setting unit 44 and superimposed on the captured images 401, 402. The inner mask 411 is a mask that is superimposed on the inside of both banks (edges) 210 of the cutting groove 200 in the captured images 401, 402, and is a mask that extends horizontally in the captured images 401, 402 and has a horizontally elongated rectangular area with a width 421 in the vertical direction. In addition, the pair of outer masks 412 are masks that are superimposed on both outer sides of the edges 210 of the cut groove 200 in the captured images 401 and 402, and have a pair of horizontally long rectangular regions that extend horizontally in the captured images 401 and 402 and are spaced vertically by a separation width 422, with the upper mask portion reaching the top of the captured images 401 and 402 and the lower mask portion reaching the bottom of the captured images 401 and 402.

In the mask setting data 350, the difference between the width 421 of the inner mask 411 and the blade thickness 21-2 of the cutting blade 21 is set to a predetermined value that allows the inner mask 411 to completely cover the area in the width direction of the cutting groove 200, which is imaged with high brightness, without partially covering both sides (edges) 210 of the cutting groove 200, when none of the allowable values of the check items in the kerf check of the condition data 300 are exceeded. In addition, in the mask setting data 350, the difference between the separation width 422 of the pair of outer masks 412 and the blade thickness 21-2 of the cutting blade 21 is set to a predetermined value that allows the pair of outer masks 412 to completely cover the TEG formed in the outer area in the width direction of the street 102, without partially covering both sides (edges) 210 of the cutting groove 200, when none of the allowable values of the check items in the kerf check of the condition data 300 are exceeded.

The present invention is not limited to the above embodiment, and the storage unit 41 may store mask setting data for each blade thickness 21-2 of the cutting blade 21, and in this mask setting data, the width 421 of the inner mask 411 and the separation width 422 of the pair of outer masks 412 may both be stored as absolute values. Furthermore, when the storage unit 41 stores the width 421 of the inner mask 411 and the separation width 422 of the pair of outer masks 412 as absolute values, the storage unit 41 may store them as a set of data in association with condition data 300 in which the blade thickness 21-2 of the cutting blade 21 is the same.

The image processing unit 42 has a mask setting unit 44 as shown in FIG. 1. The mask setting unit 44 calculates and sets the area of the inner mask 411 and the pair of outer masks 412 corresponding to the blade thickness 21-2 of the cutting blade 21, and masks the area as an area not to be detected for the cutting groove 200. As shown in FIG. 7 and FIG. 8, the image processing unit 42 sets the inner mask 411 and the pair of outer masks 412 on the captured images 401, 402 including the street 102 and the cutting groove 200 captured by the imaging unit 30 by the mask setting unit 44, and then detects the cutting groove 200 based on the captured images 401, 402 in which these masks are set. The determination unit 43 determines whether or not the multiple check items in the kerf check exceed the allowable values set for each of them in the condition data 300 based on the cutting groove 200 detected by the image processing unit 42. Details of the processing by the image processing unit 42, the determination unit 43, and the mask setting unit 44 will be described later in the description of the operation of the cutting device 1.

In this embodiment, the control unit 40 includes a computer system. The computer system included in the control unit 40 includes an arithmetic processing device having a microprocessor such as a CPU (Central Processing Unit), a storage device having a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input/output interface device. In this embodiment, the function of the control unit 40 is realized by the arithmetic processing device of the computer system included in the control unit 40 executing a computer program stored in the storage device of the computer system included in the control unit 40. The arithmetic processing device of the control unit 40 performs arithmetic processing according to the computer program stored in the storage device of the control unit 40, and outputs a control signal for controlling the cutting device 1 to each component of the cutting device 1 via the input/output interface device of the control unit 40.

In this embodiment, the function of the memory unit 41 is realized by a storage device of the computer system included in the control unit 40. In this embodiment, the functions of the image processing unit 42, the determination unit 43, and the mask setting unit 44 are realized by an arithmetic processing unit of the computer system included in the control unit 40 executing a computer program stored in the storage device of the computer system included in the control unit 40.

The notification unit 50 notifies the result of the determination made by the determination unit 43 as to whether or not the multiple check items in the kerf check exceed the tolerances set for each item. As shown in FIG. 1, the notification unit 50 has a display unit 51 and a light-emitting unit 52. The display unit 51 is composed of a condition editing screen for editing the condition data 300 stored in the memory unit 41, and a liquid crystal display device for displaying the status and images of various operations of the cutting device 1, such as cutting operations and imaging operations. The display unit 51 switches the screens and images to be displayed by being controlled by the control unit 40. The display unit 51 notifies the operator of the cutting device 1 of the results determined by the determination unit 43 by displaying result display screens 501 and 502 that show the results determined by the determination unit 43.

The light-emitting unit 52 is composed of a light-emitting diode or the like, and is controlled by the control unit 40 to light up, flash, and turn off. By lighting up, flashing, and turning off, the light-emitting unit 52 notifies the operator of the cutting device 1 of the result of the judgment by the judgment unit 43, for example, in the form of whether the judgment result was pass or fail. The notification unit 50 is not limited to this in the present invention, and may also be composed of a speaker or the like and include an audio unit that emits sound.

The display unit 51 is also provided with an input unit 53 that is used by an operator or the like to input various information and the like in order to edit the condition data 300. In this embodiment, the input unit 53 is composed of at least one of a touch panel provided on the display unit 51 and a keyboard or the like.

The cassette mounting table 60 is a mounting table on which a cassette, which is a container for storing multiple workpieces 100, is placed, and the cassette placed thereon is raised and lowered in the Z-axis direction. The workpieces 100 before cutting that are stored in a cassette placed on the cassette mounting table 60 are transported one by one by a transport unit (not shown) to the chuck table 10, where they are subjected to cutting processing by the cutting unit 20 and cleaning processing by a cleaning unit (not shown), and then placed back into the cassette by the transport unit.

Next, this specification describes the operation and processing of the cutting device 1 according to the embodiment with reference to the drawings. FIG. 5 is a cross-sectional view showing an example of the cutting operation of the cutting device 1 of FIG. 1. FIG. 6 is a cross-sectional view showing an example of the imaging operation of the cutting device 1 of FIG. 1. FIG. 7 is a diagram showing a result display screen 501, which is an example of a result display screen of the kerf check in the cutting device 1 of FIG. 1. FIG. 8 is a diagram showing a result display screen 502, which is another example of a result display screen of the kerf check in the cutting device 1 of FIG. 1.

The control unit 40 first obtains information on the type of cutting blade 21 attached to the spindle 22 from the cutting unit 20, and obtains information on the blade thickness 21-2 of the cutting blade 21 attached to the spindle 22 based on the information on the type of cutting blade 21 obtained from the cutting unit 20. Based on the obtained information on the blade thickness 21-2 of the cutting blade 21, the control unit 40 selects condition data 300 that can be used when controlling the cutting device 1 to perform the cutting process of the workpiece 100 and when performing a kerf check on the cutting groove 200 formed in the cutting process, requests an operator or the like to input which of the selected condition data 300 to use, and determines the condition data 300 to be used in response to the input received from the operator or the like.

The control unit 40 refers to the condition data 300 determined based on the information on the blade thickness 21-2 of the cutting blade 21, and causes the cutting device 1 to perform a cutting operation according to the cutting conditions of this condition data 300. Specifically, the control unit 40 first controls the chuck table 10 to suction-hold the workpiece 100 according to the cutting conditions of the condition data 300 from the back surface 104 side on the holding surface 11 of the chuck table 10 via the adhesive tape 105, and then controls the imaging unit 30 to obtain an image for performing alignment, and performs the alignment. Next, as shown in FIG. 5, the control unit 40 controls the spindle 22 to rotate the cutting blade 21 according to the cutting conditions of the condition data 300, while controlling the X-axis movement unit, the Y-axis movement unit, and the Z-axis movement unit to move the cutting blade 21 along the street 102 relative to the workpiece 100 held on the chuck table 10, thereby cutting the workpiece 100 with the cutting blade 21 to form a cutting groove 200 along the street 102.

After forming the cutting groove 200 along the street 102, the control unit 40 controls the imaging unit 30 as shown in FIG. 6 to capture an image of an area straddling one street 102 and the cutting groove 200 on the surface 101 of the workpiece 100 after cutting, and performs an imaging operation to obtain captured images 401, 402 for performing a kerf check, etc. In this embodiment, as shown in FIG. 7 and FIG. 8, the imaging unit 30 captures the captured images 401, 402 by setting the imaging magnification and angle of view so that only one street 102 extending laterally and one cutting groove 200 formed along the street 102 are positioned in the center of the captured images 401, 402.

In the present embodiment shown in FIG. 6, the control unit 40 captures the previously formed cutting groove 200 before forming the cutting groove 200 along all the streets 102, i.e., during the machining of the workpiece 100, to obtain the captured images 401, 402. Therefore, in this embodiment, if an abnormality occurs in the cutting groove 200 during the machining of the workpiece 100, it is possible to quickly respond to the abnormality. Note that the present invention is not limited to this, and the cutting groove 200 may be captured and the captured images 401, 402 obtained after the cutting groove 200 is formed along all the streets 102, i.e., after the workpiece 100 is machined.

In the captured images 401 and 402 obtained by the control unit 40 capturing images with the imaging unit 30, the cutting groove 200 formed on the surface 101 of the workpiece 100 hardly reflects the illumination light, so the amount of light incident on the imaging element of the imaging unit 30 is small, and the image is captured with low brightness. However, in the captured images 401 and 402, for example, if the cutting groove 200 formed is shallow and wide, the central region in the width direction of the cutting groove 200 may reflect the illumination light, so that the amount of light incident on the imaging element of the imaging unit 30 may be large, and the image may be captured with high brightness. In this embodiment, the brightness in the captured images 401 and 402 is specified in multiple gradations, for example, 256 gradations, and is expressed as an integer value from 0 to 255, with the darkest being represented by the minimum value 0 and the brightest being represented by the maximum value 255, and the brighter the image, the larger the value.

The mask setting unit 44 automatically sets an inner mask 411 in the area inside the width direction of both sides (edges) 210 of the cutting groove 200 in correspondence with the blade thickness 21-2 of the cutting blade 21 before the image processing unit 42 detects the cutting groove 200 from the captured images 401 and 402. By masking the inner area as an area outside the detection target of the cutting groove 200, the risk of the image processing unit 42 erroneously detecting an area that is captured with high brightness in the central area of the width direction of the cutting groove 200 as an area outside the both sides (edges) 210 of the cutting groove 200 is reduced.

Specifically, the mask setting unit 44 first refers to the mask setting data 350 stored in the storage unit 41, and calculates the width 421 of the inner mask 411 by subtracting the difference (relative value, 0.015 mm in the example shown in FIG. 4) corresponding to the width 421 of the inner mask 411 in the mask setting data 350 from the blade thickness 21-2 of the cutting blade 21. The mask setting unit 44 then sets the inner mask 411 by superimposing the inner mask 411 of the calculated width 421 on the central region of the street 102 in the captured images 401 and 402, for example, so that the center line of the inner mask 411 and the center line 111 of the street 102 overlap each other, as shown in FIGS. 7 and 8. Note that in this embodiment, the center line 111 of the street 102 overlaps with the center line extending horizontally in the captured images 401 and 402. In the example shown in FIG. 7, the mask setting unit 44 sets an inner mask 411 with a width 421 of 0.010 mm superimposed on the captured image 401, corresponding to the blade thickness 21-2 of the cutting blade 21 being 0.025 mm, and in the example shown in FIG. 8, the mask setting unit 44 sets an inner mask 411 with a width 421 of 0.025 mm superimposed on the captured image 402, corresponding to the blade thickness 21-2 of the cutting blade 21 being 0.040 mm.

In addition, in the captured images 401 and 402, the surface 101 of the workpiece 100 reflects the illumination light favorably, so the amount of light incident on the imaging element of the imaging unit 30 is large and the image is captured with high brightness. However, in the captured images 401 and 402, since the TEG is formed in the outer region in the width direction of the street 102, the TEG positioned in the outer region in the width direction of the cutting groove 200 has an area that hardly reflects the illumination light, so the amount of light incident on the imaging element of the imaging unit 30 is small, and there is a risk that the brightness of that area will be low.

Therefore, before the image processing unit 42 detects the cutting groove 200 from the captured images 401 and 402, the mask setting unit 44 automatically sets a pair of outer masks 412 in the area outside the width direction of both banks (edges) 210 of the cutting groove 200 in correspondence with the blade thickness 21-2 of the cutting blade 21, thereby masking the outer area as an area outside the detection target of the cutting groove 200, thereby reducing the risk that the image processing unit 42 will erroneously detect an area of the TEG positioned outside the width direction of the cutting groove 200 that is imaged with low brightness as being part of the cutting groove 200.

Specifically, the mask setting unit 44 first refers to the mask setting data 350 stored in the storage unit 41, and calculates the separation width 422 of the pair of outer masks 412 by adding the difference (relative value, 0.040 mm in the example shown in FIG. 4) corresponding to the separation width 422 of the pair of outer masks 412 in the mask setting data 350 to the blade thickness 21-2 of the cutting blade 21. The mask setting unit 44 then sets the pair of outer masks 412 by superimposing the pair of outer masks 412 with the calculated separation width 422 on the upper and lower regions of the captured images 401, 402, for example, so that the center line that bisects the separation width 422 of the pair of outer masks 412 and the center line 111 of the street 102 overlap, as shown in FIGS. 7 and 8. In the example shown in FIG. 7, the mask setting unit 44 sets a pair of outer masks 412 with a separation width 422 of 0.065 mm superimposed on the captured image 401, corresponding to the blade thickness 21-2 of the cutting blade 21 being 0.025 mm, and in the example shown in FIG. 8, the mask setting unit 44 sets a pair of outer masks 412 with a separation width 422 of 0.080 mm superimposed on the captured image 402, corresponding to the blade thickness 21-2 of the cutting blade 21 being 0.040 mm.

In this embodiment, the mask setting unit 44 sets the inner mask 411 and a pair of outer masks 412, but the present invention is not limited to this. For example, when the central region of the cutting groove 200 is unlikely to reflect the illumination light in order to form the cutting groove 200 deep or narrow, the setting of the inner mask 411 may be omitted, and when no TEG is formed in the outer region of the street 102 of the workpiece 100 in the width direction, the setting of the pair of outer masks 412 may be omitted.

After the mask setting unit 44 sets the inner mask 411 and the pair of outer masks 412, the image processing unit 42 detects, in the remaining area obtained by removing the area in which the inner mask 411 and the pair of outer masks 412 are set from the captured images 401 and 402, an area having a brightness equal to or less than a predetermined threshold value that is lower than the brightness when the surface 101 of the workpiece 100 is imaged and higher than the brightness when the cutting groove 200 is imaged, as part of the area in which the cutting groove 200 is formed on the surface 101 of the workpiece 100. In addition, the image processing unit 42 processes the area in which the inner mask 411 is set as part of the remaining area in which the cutting groove 200 is formed on the surface 101 of the workpiece 100, and processes the areas other than the area in which the cutting groove 200 is formed in the captured images 401 and 402 (including the area in which the pair of outer masks 412 are set) as areas in which the cutting groove 200 is not formed.

The image processing unit 42 further detects the boundary area between the area where the cutting groove 200 is formed on the surface 101 of the workpiece 100 and the area where the cutting groove 200 is not formed on the surface 101 of the workpiece 100 as both sides (edges) 210 of the cutting groove 200. The image processing unit 42 also detects the linear ends 220 of the cutting groove 200 by performing a calculation process that linearly connects the extreme values protruding inward in the width direction of the cutting groove 200 for each edge 210 of the cutting groove 200 based on both sides (edges) 210 of the cutting groove 200. Here, both ends 220 of the cutting groove 200 are lines obtained by removing the areas caused by chipping that occurred in the cutting groove 200 from both sides (edges) 210 of the cutting groove 200, and are lines that represent the width (kerf width) of the cutting groove 200 from which the chipping has been removed. In addition, both ends 220 of the cut groove 200 are one of the reference lines for measuring the size of the chipping that protrudes in the width direction. Furthermore, the image processing unit 42 detects the kerf center 201 of the cut groove 200 by calculating the center line of both ends 220 of the cut groove 200 based on both ends 220 of the cut groove 200. The kerf center 201 is a line that indicates the position of the cut groove 200 in the width direction, and is another reference line for measuring the size of the chipping in the width direction.

The image processing unit 42 detects multiple items to be checked in the kerf check, namely, off-center 202, kerf width Max 203, kerf width Min 204, chipping width 205 from the kerf center 201, and max chipping width 206 from the kerf end, based on the detected edges 210, both ends 220, and kerf center 201 of the cutting groove 200, and the center line 111 of the street 102 that is set in advance in the center of the captured images 401, 402.

The determination unit 43 determines whether the detection value detected by the image processing unit 42 exceeds the allowable value stored in the storage unit 41 as the condition data 300 for each of the multiple check items in the kerf check. For check items that specify the maximum allowable value (in this embodiment, off-center 202, kerf width Max 203, chipping width 205 from kerf center 201, and Max chipping width 206 from kerf end), the determination unit 43 determines that the allowable value is not exceeded if the check item is equal to or less than the allowable value, and determines that the allowable value is exceeded if the check item is greater than the allowable value. In addition, for check items that specify the minimum allowable value (in this embodiment, kerf width Min 204), the determination unit 43 determines that the allowable value is not exceeded if the check item is equal to or more than the allowable value, and determines that the allowable value is exceeded if the check item is smaller than the allowable value.

When the detection value detected by the image processing unit 42 for a check item in a kerf check does not exceed the allowable value, the judgment unit 43 judges that the check item in the kerf check is normal. In addition, when the detection value detected by the image processing unit 42 for a check item in a kerf check exceeds the allowable value, the judgment unit 43 judges that an abnormality has occurred in the check item in the kerf check.

The image processing unit 42 refers to the layout data and data of various image elements stored in the memory unit 41, and arranges the captured images 401, 402 in which the mask setting unit 44 sets the inner mask 411 and the pair of outer masks 412, the width 421 of the inner mask 411 and the separation width 422 of the pair of outer masks 412 calculated by the mask setting unit 44 with reference to the mask setting data 350, the multiple check items and their tolerances in the kerf check stored in the memory unit 41 as condition data 300, and the detection values of the multiple check items in the kerf check detected by the image processing unit 42, as shown in Figures 7 and 8, and generates result display screens 501, 502 by attaching a conspicuous display to the column of the check item that the judgment unit 43 judges to have an abnormality, and displays them on the display unit 51 of the notification unit 50. The display unit 51 notifies the result of the judgment by the judgment unit 43 by displaying the result display screens 501, 502 including information on the result judged by the judgment unit 43 in this way. In the example shown in FIG. 7, the display unit 51 notifies that the cutting groove 200 is normal because all check items are normal, and in the example shown in FIG. 8, it notifies that the cutting groove 200 is abnormal because an abnormality has occurred in the chipping width 205 from the calf center 201. Note that the conspicuous display added to the column of the check item determined to be abnormal is a conspicuous highlight display in the column displaying the allowable value and detection value of the check item in the example shown in FIG. 8, but the present invention is not limited to this, and any display that can be seen by the worker at a glance may be used, such as changing the type, color, size, etc. of the font displaying the check item, allowable value, detection value, etc. to make it conspicuous, or flashing the display.

The light-emitting unit 52 of the alarm unit 50 lights up, for example, blue or green when all check items are normal and the cutting groove 200 is normal, while it flashes, for example, a conspicuous red light when at least one check item is abnormal and the cutting groove 200 is abnormal, thereby notifying the operator, etc., of the result determined by the determination unit 43.

In the cutting device 1 according to the embodiment having the above configuration, the mask setting unit 44 automatically calculates and sets the area (width 421) of the inner mask 411 to be set on the inside in the width direction of both sides (edges) 210 of the cutting groove 200 in accordance with the blade thickness 21-2 of the cutting blade 21, and calculates and sets the area (separation width 422) of a pair of outer masks 412 to be set on the outside in the width direction of both sides (edges) 210 of the cutting groove 200. That is, the cutting device 1 according to the embodiment automatically changes the mask setting according to the blade thickness 21-2 of the cutting blade 21. Therefore, the cutting device 1 according to the embodiment has the effect of suppressing erroneous detection of the cutting groove 200 due to forgetting to change the mask setting corresponding to the blade thickness 21-2 of the cutting blade 21.

The present invention is not limited to the above embodiment. In other words, the present invention can be implemented in various modifications without departing from the gist of the invention.

REFERENCE SIGNS LIST 1 Cutting device 10 Chuck table 20 Cutting unit 21 Cutting blade 21-2 Blade thickness 22 Spindle 30 Imaging unit 41 Storage unit 42 Image processing unit 43 Determination unit 44 Mask setting unit 50 Notification unit 100 Workpiece 200 Cut groove 210 Edge
220 edge 411 inner mask 412 outer mask

Claims (2)

A cutting device including a chuck table for holding a workpiece, and a cutting unit for forming a cutting groove in the workpiece held on the chuck table with a cutting blade attached to a spindle,
an imaging unit for capturing an image of the cut groove formed in the workpiece during processing;
A memory unit that stores cutting conditions for cutting a workpiece, check items for checking the quality of the cut groove and allowable values for the check items, and information on the blade thickness of the cutting blade;
an image processing unit that detects the cutting groove from the captured image;
a determination unit that determines whether or not each of the plurality of check items exceeds the allowable value based on the cutting groove detected by the image processing unit;
a notification unit that notifies the result of the determination by the determination unit,
the image processing unit has a mask setting unit that, when detecting the cutting groove from the captured image, masks an area inside or outside both banks of the cutting groove as an area outside the detection target of the cutting groove,
The cutting device is characterized in that the mask setting unit calculates and sets the area in accordance with the cutting blade thickness stored in the memory unit . The memory unit further stores a difference between the blade thickness of the cutting blade and the width of the inner region,
2. The cutting device according to claim 1, wherein the mask setting unit calculates the width based on the blade thickness of the cutting blade and the difference, and sets the inner region.

Images