Cutting device
The cutting device dynamically adjusts blade position checks based on actual displacement, addressing spindle expansion issues and ensuring accurate cutting by optimizing inspection frequency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DISCO CORP
- Filing Date
- 2022-10-04
- Publication Date
- 2026-07-22
AI Technical Summary
Existing cutting devices struggle with spindle expansion and contraction during cutting, leading to unpredictable blade misalignment, which current inspection methods fail to address adequately, resulting in inaccurate cutting or excessive inspection frequency.
A cutting device with a controller that adjusts the frequency of blade position checks based on actual displacement, using a camera to photograph cutting marks and recalculating the inspection frequency based on the number of processed lines and calculated deviation, allowing for appropriate adjustment of blade position.
The device effectively checks and adjusts blade misalignment at a frequency tailored to the cutting conditions, maintaining cutting accuracy and reducing unnecessary inspections.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a cutting device used when cutting a workpiece.
Background Art
[0002] When cutting (machining) a plate-shaped workpiece typified by a semiconductor wafer, for example, a cutting device in which an annular cutting blade is attached to a spindle is used. While cutting the workpiece with the cutting blade rotating at high speed, the cutting blade and the workpiece are relatively moved, and the workpiece is cut along the path of this movement.
[0003] By the way, in the cutting device as described above, due to the influence of heat and the like generated during cutting of the workpiece, the spindle expands and contracts, and the position of the cutting blade attached to this spindle may deviate from the position of the cutting blade stored in the cutting device in advance. Thus, when the position of the cutting blade deviates from the pre-stored position, the position of the cutting blade with respect to the workpiece also deviates, and the accuracy of cutting the workpiece decreases.
[0004] Therefore, an inspection called a kerf check or the like is performed at a predetermined frequency, in which a cutting mark formed by cutting the workpiece is photographed with a camera or the like, and the position of the cutting blade is confirmed based on the position of the cutting mark in the generated image (see, for example, Patent Document 1). When a deviation in the position of the cutting blade is detected in this inspection, the cutting device corrects, for example, the position of the cutting blade stored by itself according to the amount of the detected deviation and the like.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] However, the degree of spindle expansion and contraction varies greatly depending on the cutting conditions of the workpiece, so the amount of displacement of the cutting blade may not fall within the range anticipated in advance. Furthermore, the above method of inspection, which involves performing inspections at predetermined intervals, cannot adequately address situations where the amount of displacement of the cutting blade is smaller or larger than anticipated.
[0007] For example, if the actual displacement of the cutting blade is smaller than expected, it results in an extra number of inspections being performed, increasing the amount of time the cutting machine is unable to cut the workpiece compared to when inspections are performed at the ideal frequency. On the other hand, if the displacement of the cutting blade is larger than expected, the number of inspections will be insufficient, which can easily lead to a decrease in the accuracy of cutting the workpiece.
[0008] Therefore, the object of the present invention is to provide a cutting device that can check the misalignment of the cutting blade at a frequency appropriate to the situation. [Means for solving the problem]
[0009] According to one aspect of the present invention, a cutting device is provided that includes a chuck table for holding a workpiece on which a processing line is set, a cutting unit having a spindle on which a cutting blade is mounted, and cutting the workpiece held by the chuck table along the processing line with the cutting blade to form cutting marks on the workpiece, a camera for photographing the workpiece held by the chuck table, and a controller having a processing device and a storage device, which operates according to one or more programs stored in the storage device, wherein the controller, according to the program, causes the camera to photograph the workpiece after it has been cut by the cutting unit at a frequency stored in the storage device to acquire an image showing the cutting marks, calculates the amount of deviation between the position of the cutting blade stored in the storage device and the actual position of the cutting blade based on the position of the cutting marks shown in the image, and resets the frequency at which the camera photographs the workpiece based on the number of processing lines cut by the cutting unit and the calculated amount of deviation.
[0010] Preferably, the controller further includes a notification unit that notifies information regarding the amount of the misalignment, and the controller determines, according to the program, whether the calculated amount of misalignment belongs to a first range to which misalignment amounts of a predetermined size belong, or to a second range to which misalignment amounts smaller than those in the first range belong, and if the calculated amount of misalignment belongs to the first range, it notifies the notification unit to that effect, and if the calculated amount of misalignment belongs to the second range, it corrects the position of the cutting blade stored in the storage device based on the calculated amount of misalignment.
[0011] Preferably, the controller determines, according to the program, whether the calculated amount of deviation belongs to a first range to which deviations of a predetermined size belong, a second range to which deviations smaller than those in the first range belong, or a third range to which deviations smaller than those in the second range belong. If the calculated amount of deviation belongs to the third range, the controller continues cutting the workpiece by the cutting unit without correcting the position of the cutting blade stored in the storage device. [Effects of the Invention]
[0012] In a cutting apparatus according to one aspect of the present invention, the controller causes the camera to photograph the workpiece after it has been cut by the cutting unit at a frequency stored in the storage device to acquire images showing the cutting marks. Based on the position of the cutting marks in the images, the controller calculates the amount of deviation between the position of the cutting blade stored in the storage device and the actual position of the cutting blade. Based on the number of processing lines cut by the cutting unit and the calculated amount of deviation, the controller resets the frequency at which the camera photographs the workpiece. Thus, in a cutting apparatus according to one aspect of the present invention, the deviation of the cutting blade position can be checked at a frequency appropriate to the situation. [Brief explanation of the drawing]
[0013] [Figure 1] Figure 1 is a schematic perspective view of the cutting apparatus. [Figure 2] Figure 2 is a functional block diagram that schematically shows a part of the functional structure of the controller. [Figure 3] Figure 3 is a flowchart showing the process for resetting the calf check frequency. [Figure 4] Figure 4 shows an example of an image acquired by the camera. [Modes for carrying out the invention]
[0014] Embodiments of the present invention will be described below with reference to the attached drawings. Figure 1 is a schematic perspective view of the cutting apparatus 2 of this embodiment. In Figure 1, some components of the cutting apparatus 2 are represented by functional blocks. Also, the X, Y, and Z axes used in the following description are perpendicular to each other.
[0015] As shown in Figure 1, the cutting device 2 includes a base 4 that supports multiple components. An opening 4a is formed at the corner of the base 4, and a cassette support base 6, which moves up and down by a lifting mechanism (not shown), is positioned in this opening 4a. A cassette 8 capable of accommodating multiple workpieces 11 is placed on the upper surface of the cassette support base 6. Note that in Figure 1, only the outline of the cassette 8 is shown for the sake of explanation.
[0016] The workpiece 11 is, for example, a disc-shaped wafer (semiconductor wafer) formed using a semiconductor such as silicon. The surface (top surface in Figure 1) of this workpiece 11 is divided into multiple small regions by multiple intersecting processing lines (streets), and a device 13 such as an IC (Integrated Circuit) is formed in each small region.
[0017] A circular tape (dicing tape) 15, with a larger diameter than the workpiece 11, is attached to the back side (bottom side in Figure 1) of the workpiece 11. The outer circumference of the tape 15 is fixed to an annular frame 17 that surrounds the workpiece 11. The workpiece 11 is placed in the cassette 8 while being supported by the frame 17 via this tape 15.
[0018] In this embodiment, a disc-shaped wafer formed using a semiconductor such as silicon is exemplified as the workpiece 11, but the material, shape, structure, size, etc. of the workpiece 11 are not limited to this embodiment. For example, a substrate formed using other semiconductors, ceramics, resins, metals, etc. may be used as the workpiece 11.
[0019] Similarly, the type, quantity, shape, structure, size, arrangement, etc., of the device 13 are not limited to the embodiments of this model. The device 13 does not need to be formed on the workpiece 11. The tape 15 may be attached to the surface side of the workpiece 11. Furthermore, a protective plate or the like may be attached to the workpiece 11 instead of the tape 15.
[0020] On the side of the opening 4a, an opening 4b that is long in the direction along the X-axis (front-rear direction) is formed. Inside this opening 4b, a ball screw type table movement mechanism 10 is arranged. The table movement mechanism 10 includes an X-axis movement table (not shown), and moves this X-axis movement table along the X-axis. The upper parts of the table movement mechanism 10 and the X-axis movement table are covered by a table cover 12 and a bellows cover 14.
[0021] On the X-axis movement table, for example, a chuck table 16 that holds the workpiece 11 during cutting is arranged in a manner that is exposed upward from the table cover 12. The chuck table 16 is connected to a rotational drive source (not shown) such as a motor, and rotates around a rotation axis that is generally parallel to the Z-axis. Also, the chuck table 16 moves along the X-axis together with the X-axis movement table etc. by the above-described table movement mechanism 10 (machining feed).
[0022] A part of the upper surface of the chuck table 16 becomes a holding surface 16a that holds the workpiece 11. This holding surface 16a is connected to a suction source (not shown) such as an ejector via a suction path (not shown) formed inside the chuck table 16. Also, around the chuck table 16, four clamps 18 for fixing a frame 17 that supports the workpiece 11 are provided.
[0023] In a region adjacent to the opening 4b, a conveying mechanism (not shown) for conveying the above-described workpiece 11 to the chuck table 16 etc. is arranged. The workpiece 11 carried out from the cassette 8 by the conveying mechanism is placed on the chuck table 16, for example, in a manner that the surface side is exposed upward.
[0024] A gate-shaped support structure 20 is positioned on the upper surface of the base 4, straddling the opening 4b along the Y-axis. A pair of cutting unit moving mechanisms 22 are provided on the upper front of the support structure 20. Each cutting unit moving mechanism 22 is equipped with a pair of Y-axis guide rails 24 that are positioned on the front of the support structure 20 and are generally parallel to the Y-axis. Y-axis moving plates 26 that constitute each cutting unit moving mechanism 22 are attached to the Y-axis guide rails 24 in such a manner that they can slide along the Y-axis.
[0025] Each Y-axis moving plate 26 is provided with a nut portion (not shown) on its back (rear) side, which constitutes a ball screw. A screw shaft 28, which is generally parallel to the Y-axis guide rail 24, is connected to this nut portion in a manner that allows it to rotate. A Y-axis pulse motor 30 is connected to one end of the screw shaft 28. When the screw shaft 28 is rotated by the Y-axis pulse motor 30, the Y-axis moving plate 26 moves along the Y-axis on the Y-axis guide rail 24.
[0026] A pair of Z-axis guide rails 32, roughly parallel to the Z-axis, are arranged on the front surface of the Y-axis moving plate 26. The Z-axis moving plate 34 is mounted on the Z-axis guide rails 32 in such a manner that it can slide along the Z-axis. A nut portion (not shown) that constitutes a ball screw is provided on the back surface (rear side) of the Z-axis moving plate 34.
[0027] A screw shaft 36, which is roughly parallel to the Z-axis guide rail 32, is connected to this nut in a manner that allows it to rotate. A Z-axis pulse motor 38 is connected to one end of the screw shaft 36. When the screw shaft 36 is rotated by the Z-axis pulse motor 38, the Z-axis moving plate 34 moves along the Z-axis on the Z-axis guide rail 32.
[0028] A cutting unit 40 used for cutting the workpiece 11 is provided at the lower part of the Z-axis moving plate 34. The cutting unit 40 includes, for example, a cylindrical spindle housing. A spindle, whose axis of rotation is approximately parallel to the Y-axis, is housed in the space inside the spindle housing.
[0029] A rotational drive source, such as a motor, is connected to the base end of the spindle. The tip of the spindle is exposed to the outside from the spindle housing, and a cutting blade 42 is mounted on this tip of the spindle via a blade mount. The cutting blade 42 is obtained, for example, by fixing abrasive grains such as diamond with a binder such as resin, and is formed in an annular shape having a pair of generally flat sides.
[0030] Furthermore, a camera 44 is fixed to the lower part of the Z-axis moving plate 34. This camera 44 includes, for example, a two-dimensional optical sensor such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor that is sensitive to visible light, and an imaging lens. The camera 44 is used, for example, to capture an image of a workpiece 11 held by the chuck table 16 and acquire an image.
[0031] When the Y-axis moving plate 26 of the cutting unit moving mechanism 22 is moved along the Y-axis, both the cutting unit 40 and the camera 44 move along the Y-axis (indexing feed). Similarly, when the Z-axis moving plate 34 of the cutting unit moving mechanism 22 is moved along the Z-axis, both the cutting unit 40 and the camera 44 move along the Z-axis (depth of cut feed).
[0032] When cutting the workpiece 11, for example, the cutting unit 40 moves to a position where the lower end of the cutting blade 42 is lower than the surface (top surface) of the workpiece 11 held by the chuck table 16. Then, with the cutting blade 42 rotating, the chuck table 16 moves along the X-axis, causing the cutting blade 42 to cut into the workpiece 11. As a result, the workpiece 11 is cut by the cutting blade 42, and a cutting mark along the X-axis is formed on the workpiece 11.
[0033] A circular opening 4c is formed on the opposite side of opening 4a from opening 4b. A cleaning unit 46 is located inside opening 4c. The cleaning unit 46 includes a spinner table 48 that holds the workpiece 11 inside opening 4c. A rotational drive source (not shown), such as a motor, is connected to the lower part of the spinner table 48 to rotate the spinner table 48.
[0034] Above the spinner table 48, a nozzle 50 is positioned to spray a cleaning fluid (typically a mixed fluid of water and air) onto the workpiece 11 held by the spinner table 48. As the spinner table 48 rotates while holding the workpiece 11, the cleaning fluid is sprayed from the nozzle 50 onto the workpiece 11, thereby cleaning the workpiece 11.
[0035] The components of the cutting apparatus 2, such as the table moving mechanism 10, the cutting unit moving mechanism 22, the cutting unit 40, the camera 44, and the cleaning unit 46, are each connected to a controller (control unit) 52. The controller 52 is composed of a computer, for example, a processing unit 54 and a storage device 56, and controls the above-mentioned components in accordance with a series of processes required for cutting the workpiece 11.
[0036] The processing unit 54 is typically a CPU (Central Processing Unit) and performs various processes necessary to control each component. The storage device 56 includes, for example, a main memory such as DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive or flash memory. The functions of this controller 52 are realized, for example, by the operation of the processing unit 54 according to one or more programs (software) stored in the storage device 56.
[0037] The top of the base 4 is covered by a cover (not shown). A touchscreen (display device (notification unit), input device) 58, which serves as the user interface, is located on the side of this cover. An indicator light (notification unit) 60 is located on the top of the cover. The touchscreen 58 and indicator light 60 are connected to the controller 52 described above.
[0038] Furthermore, a speaker (notification unit) or the like connected to the controller 52 may be placed on the cover. Also, instead of the touchscreen 58 which integrates the display device (notification unit) and the input device, a display device (notification unit) such as a liquid crystal display and an input device such as a keyboard or mouse may be connected to the controller 52 separately. Moreover, a portable terminal such as a smartphone may be used as the display device (notification unit) or input device.
[0039] Figure 2 is a functional block diagram schematically showing a part of the functional structure of the controller 52. As described above, many of the functions of the controller 52 shown in Figure 2 are realized by the operation of the processing unit 54 according to one or more programs (software) stored in the storage device 56.
[0040] As shown in Figure 2, the controller 52 includes a position memory unit 52a as part of the storage device 56, which stores the reference position of the cutting blade 42 mounted on the spindle. In this position memory unit 52a, for example, the position of the cutting blade 42 in the direction along the Y-axis (Y-coordinate) relative to the camera 44 is stored as the reference position of the cutting blade 42.
[0041] Furthermore, the controller 52 includes a frequency memory unit 52b as part of the memory device 56, which stores information regarding the frequency at which an inspection (hereinafter referred to as "kerf check") is performed to confirm the positional deviation of the cutting blade 42. Typically, this frequency memory unit 52b stores information regarding the frequency (period) of the kerf check, which is determined by the number of planned machining lines. For example, if 30 planned machining lines are set as the frequency for the kerf check, the kerf check will start when machining is completed on all 30 planned machining lines.
[0042] Furthermore, the controller 52 includes an image capture control unit 52c that causes the camera 44 to photograph the workpiece 11 after it has been cut by the cutting unit 40, and acquires an image showing the cutting marks. When the timing for a kerf check, as indicated by the information stored in the frequency memory unit 52b, arrives, the image capture control unit 52c causes the camera 44 to photograph the workpiece 11 so that the target cutting marks (typically, the last cutting marks formed) are captured. Thus, the frequency of kerf checks stored in the frequency memory unit 52b corresponds to the frequency at which the camera 44 photographs the workpiece 11.
[0043] Furthermore, the controller 52 includes a displacement calculation unit 52d that calculates the amount of difference between the position of the cutting blade 42 stored in the position memory unit 52a and the actual position of the cutting blade 42, based on the position of the cutting marks captured in the image acquired by the image capture control unit 52c. The amount of displacement calculated by the displacement calculation unit 52d is used for correcting the position of the cutting blade 42 stored in the position memory unit 52a, resetting the frequency of kerf checks stored in the frequency memory unit 52b, and so on.
[0044] Furthermore, the controller 52 includes a determination unit 52e that performs various judgments based on the amount of displacement calculated by the displacement calculation unit 52d. For example, if the determination unit 52e determines that the amount of displacement calculated by the displacement calculation unit 52d is greater than or equal to a first threshold, it notifies the operator of this fact via the touchscreen 58 or indicator light 60. This is because if the amount of displacement calculated by the displacement calculation unit 52d is extremely large, there is a high possibility that some kind of abnormality has occurred in the cutting device 2.
[0045] On the other hand, if the determination unit 52e determines, for example, that the amount of deviation calculated by the deviation amount calculation unit 52d is less than the first threshold and greater than or equal to a second threshold which is smaller than the first threshold, it corrects the position of the cutting blade 42 stored in the position storage unit 52a based on this amount of deviation. This suppresses a decrease in the accuracy of cutting the workpiece 11.
[0046] Furthermore, if the determination unit 52e determines that the amount of displacement calculated by the displacement amount calculation unit 52d is less than the second threshold, it resumes cutting the workpiece 11 without correcting the position of the cutting blade 42 stored in the position memory unit 52a. This is because, if the amount of displacement calculated by the displacement amount calculation unit 52d is sufficiently small, the cutting accuracy of the workpiece 11 can be maintained at a high level without correcting the position of the cutting blade 42.
[0047] In this way, the determination unit 52e determines whether the amount of displacement calculated by the displacement amount calculation unit 52d belongs to a first range to which extremely large amounts of displacement belong, a second range to which amounts of displacement smaller than the amounts of displacement belonging to the first range belong, or a third range to which amounts of displacement smaller than the amounts of displacement belonging to the second range belong, and then performs various processes according to the result of the determination.
[0048] The first threshold value, which is the boundary value between the first range and the second range, is, for example, about 10 μm to 20 μm, but it may be outside this range. Similarly, the second threshold value, which is the boundary value between the second range and the third range, is, for example, about 5 μm to 9 μm, but it may be outside this range. In this embodiment, the first range is set to be greater than or equal to the first threshold, the second range is set to be less than the first threshold and greater than or equal to the second threshold, and the third range is set to be less than the second threshold, but for example, the first range may be set to be greater than the first threshold, the second range may be set to be less than or equal to the first threshold and greater than the second threshold, and the third range may be set to be less than or equal to the second threshold.
[0049] Furthermore, the controller 52 includes a frequency resetting unit 52f that resets the frequency of kerf checks (the frequency at which the workpiece 11 is photographed by the camera 44) based on the number of machining lines cut by the cutting unit 40 and the amount of deviation calculated by the deviation amount calculation unit 52d. For example, if the amount of deviation calculated by the deviation amount calculation unit 52d is small enough that the position of the cutting blade 42 does not need to be corrected (typically, if it falls within the third range described above), the set frequency of kerf checks is higher than the appropriate frequency of kerf checks.
[0050] Furthermore, for example, if the amount of deviation calculated by the deviation amount calculation unit 52d is large to a certain extent (typically, if it is larger than the midpoint of the second range described above), the set calf check frequency is lower than the appropriate calf check frequency. In these cases, the frequency reset unit 52f resets the calf check frequency to bring it closer to the appropriate calf check frequency.
[0051] When the frequency resetting unit 52f resets the calf check frequency, the frequency storage unit 52b stores information about the reset calf check frequency, and the next calf check is performed at a timing corresponding to the reset calf check frequency (period). Figure 3 is a flowchart showing the processing flow for resetting the calf check frequency.
[0052] As shown in Figure 3, when cutting of the workpiece 11 begins, the controller 52 starts counting the number of machining lines cut by the cutting unit 40 (hereinafter referred to as "cut machining lines") (step ST11). Then, based on the counted number of cut machining lines l, the controller 52 determines whether or not the timing for a kerf check, which is set at a number of machining lines m, has arrived (step ST12). The number of machining lines m, which determines the frequency of the kerf check, is set by the operator to the controller 52 via the touchscreen 58 before cutting of the workpiece 11 begins, for example.
[0053] Based on the counted number of planned machining lines already cut, if it is determined that the time for a kerf check has arrived (YES in step ST12), the controller 52 interrupts the cutting of the workpiece 11 and starts the kerf check. Specifically, the controller 52 first has the camera 44 photograph the workpiece 11 after it has been cut by the cutting unit 40, and obtains an image showing the last (immediately before) cut mark (step ST13).
[0054] Figure 4 shows an example of an image acquired by camera 44. For the sake of explanation, image 21 in Figure 4 also shows a dashed line 21a, called the hairline center, which passes through the center of image 21 in the direction along the Y axis, and a dashed line 21b, called the kerf center, which passes through the center of the cutting mark 11a (the center in the width direction of the cutting mark 11a) in the direction along the Y axis. Here, the reference position of the cutting blade 42 is set, for example, so that when the workpiece 11 is cut by the cutting blade 42, the cutting mark 11a passes through the center of the resulting image 21.
[0055] Therefore, when the cutting blade 42 is in the reference position (when there is no displacement in the position of the cutting blade 42), the dashed line 21a passing through the center of image 21 and the dashed line 21b passing through the center of the cutting mark 11a will overlap. The amount a of displacement a of the cutting blade 42 from the reference position corresponds, for example, to the distance Δ of the displacement between the dashed line 21a and the dashed line 21b.
[0056] Therefore, after the image 21 is acquired by the camera 44, the controller 52 extracts the distance Δ between the dashed line 21a and the dashed line 21b from the image 21, and calculates, for example, its absolute value as the amount a of positional displacement of the cutting blade 42 (step ST14). In other words, the controller 52 calculates the amount a of displacement between the reference position of the cutting blade 42 and the actual position of the cutting blade 42 based on the position of the cutting marks 11a shown in the image 21.
[0057] If the value of a / l is large enough, that is, not practically zero (YES in step ST15), the controller 52 readjusts the frequency of kerf checks based on the number l of the planned machining lines that have been cut and the amount a of this deviation (step ST16). In other words, the controller 52 readjusts the frequency at which the workpiece 11 is photographed by the camera 44 based on the number l of the planned machining lines that the cutting unit 40 has cut and the calculated amount a of deviation.
[0058] For example, suppose the number of planned machining lines l that have been cut at the time the kerf check is performed is 30, and the calculated positional deviation a is 3 μm. In this case, a deviation of 0.1 μm (0.1 μm / line (= 3 μm / 30 lines)) occurs each time a planned machining line is cut.
[0059] Here, assuming that the lower limit of the amount of deviation that requires correction of the cutting blade 42's position (i.e., the lower limit of the second range) is 5 μm, in the above case, it is predicted that correction of the cutting blade 42's position will be necessary when a total of 50 planned machining lines have been cut. Therefore, in this case, the controller 52 resets the number of planned machining lines, which is the frequency of the kerf check, to 50.
[0060] More generally, if b is the lower limit of the amount of deviation that requires correction of the position of the cutting blade 42, then the number of planned machining lines n that are reset as the frequency of kerf checks can be expressed as n = l·b / a. Therefore, the controller 52 resets the number of planned machining lines, which is the frequency of kerf checks, to n (= l·b / a). Once the frequency of kerf checks is reset in this way, the process of resetting the frequency of kerf checks is completed.
[0061] After the frequency of the kerf check is reset, the controller 52 repeats the resetting process described above. Specifically, the controller 52 resumes cutting and counting the workpiece 11. Then, when the timing for the kerf check, which is set for the number n of planned machining lines, arrives, the controller 52 performs the kerf check (steps ST13 and ST14).
[0062] Subsequently, the controller 52 readjusts the frequency of kerf checks as needed (steps ST15 and ST16), and corrects the position of the cutting blade 42 based on the calculated amount of deviation a. A similar process is repeated until the cutting of the workpiece 11 is completed.
[0063] Until the position of the cutting blade 42 is corrected, the count of planned machining lines (number of already cut planned machining lines l), which is used to reset the frequency of calf checks, is accumulated. On the other hand, once the position of the cutting blade 42 is corrected, the number of already cut planned machining lines l is reset to zero. This allows the frequency of calf checks to be appropriately reset at the next calf check timing.
[0064] By the way, if the value of a / l is too small, that is, if it is practically zero (NO in step ST15), the value of l·b / a becomes extremely large, and the frequency of kerf checks cannot be properly reset. In such cases, it is desirable for the controller 52 to resume cutting the workpiece 11 without resetting the frequency of kerf checks.
[0065] For example, if the number of planned machining lines m set as the frequency for kerf checks is 30, the number of planned machining lines l that have been cut at the time the kerf check is performed is 30, the calculated positional deviation a is 0.1 μm, and the lower limit b of the deviation that requires correction of the cutting blade 42's position is 5 μm, then the number of planned machining lines n that will be reset will be 1500. However, such a large value is not realistic as a frequency for kerf checks.
[0066] Therefore, in such cases, the controller 52 resumes cutting the workpiece 11 without resetting the frequency of the kerf check. In other words, in the example described above, the kerf check is performed again when the next 30 lines to be cut have been cut. This allows the frequency of the kerf check to be appropriately reset. The range in which the a / l value is considered to be virtually zero is, for example, about 0 μm / piece to 0.01 μm / piece, but it may also be outside this range.
[0067] Subsequently, at the next kerf check timing, the controller 52 resets the frequency of the kerf check using the same procedure. For example, if the number of planned machining lines l that have been cut at the time the kerf check was performed is 60, the calculated positional deviation a is 2 μm, and the lower limit b of the deviation that requires correction of the cutting blade 42's position is 5 μm, then the number of planned machining lines n that will be reset will be 150.
[0068] As described above, in the cutting apparatus 2 according to this embodiment, the controller 52 causes the camera 44 to photograph the workpiece 11 after it has been cut by the cutting unit 40 at a frequency stored in the storage device 56 to acquire an image 21 showing the cutting marks 11a. Based on the position of the cutting marks 11a shown in the image 21, the controller 52 calculates the amount a of deviation between the position of the cutting blade 42 stored in the storage device 56 and the actual position of the cutting blade 42. Based on the number l of the planned machining lines cut by the cutting unit 40 and the calculated amount a of deviation, the controller 52 resets the frequency at which the camera 44 photographs the workpiece 11. Therefore, this cutting apparatus 2 can check the deviation of the cutting blade 42's position at a frequency appropriate to the situation.
[0069] It should be noted that the present invention is not limited to the embodiments described above and can be implemented with various modifications. For example, in the embodiments described above, one controller 52 performs all control over the cutting device 2, but for example, the process of resetting the frequency of kerf checks may be performed by a dedicated controller.
[0070] Furthermore, the structures, methods, etc., of the embodiments and modified versions described above may be modified as appropriate, as long as they do not deviate from the scope of the present invention. [Explanation of Symbols]
[0071] 2:Cutting device 4: Base 4a: Opening 4b: Opening 4c: opening 6: Cassette support stand 8: Cassette 10: Table movement mechanism 12: Table cover 14: Accordion-style cover 16: Chuck Table 16a: Holding surface 18: Clamp 20:Support structure 22: Cutting unit movement mechanism 24: Y-axis guide rail 26: Y-axis moving plate 28: Screw shaft 30: Y-axis pulse motor 32: Z-axis guide rail 34: Z-axis movement plate 36: Screw shaft 38: Z-axis pulse motor 40: Cutting Unit 42: Cutting blade 44: Camera 46: Washing Unit 48: Spinner Table 50: Nozzle 52: Controller (control unit) 52a: Position memory section 52b: Frequency memory unit 52c: Image capture control unit 52d: Calculation unit for displacement 52e: Judgment section 52f: Frequency reset section 54: Processing unit 56: Storage device 58: Touchscreen (display device (notification unit), input device) 60: Indicator light (notification unit) 11: Workpiece 11a: Cutting marks 13: Device 15: Tape (Dicing Tape) 17: Frame 21: Image
Claims
1. A chuck table that holds the workpiece on which the processing line is scheduled, A cutting unit having a spindle on which a cutting blade is mounted, and cutting the workpiece held by the chuck table along the planned cutting line with the cutting blade to form a cutting mark on the workpiece, A camera for photographing the workpiece held by the chuck table, A controller having a processing unit and a storage device, which operates according to one or more programs stored in the storage device, The controller, in accordance with the program, The workpiece after being cut by the cutting unit is photographed by the camera at a frequency stored in the storage device, and an image showing the cutting marks is obtained. Based on the position of the cutting marks shown in the image, the amount of discrepancy between the position of the cutting blade stored in the storage device and the actual position of the cutting blade is calculated. A cutting device that readjusts the frequency at which the camera photographs the workpiece, based on the number of planned machining lines cut by the cutting unit and the calculated amount of deviation.
2. It further includes a notification unit that notifies information regarding the amount of the deviation, The controller, in accordance with the program, The calculated amount of deviation is then determined to belong to either a first range, which includes deviations of a predetermined magnitude, or a second range, which includes deviations smaller than those in the first range. The cutting apparatus according to claim 1, wherein if the calculated amount of the deviation falls within the first range, the notification unit is notified to that effect, and if the calculated amount of the deviation falls within the second range, the position of the cutting blade stored in the storage device is corrected based on the calculated amount of the deviation.
3. The controller, in accordance with the program, The calculated amount of deviation is then determined to belong to one of three ranges: a first range to which deviations of a predetermined magnitude belong; a second range to which deviations smaller than those in the first range belong; and a third range to which deviations smaller than those in the second range belong. The cutting apparatus according to claim 2, wherein, if the calculated amount of deviation falls within the third range, the cutting unit continues cutting the workpiece without correcting the position of the cutting blade stored in the storage device.