Processing device and method for determining workpiece

Abstract

To provide a processing device capable of preventing an error processing of a processed material.SOLUTION: A processing device for processing a processed material, comprises: a chuck table having a holding surface that holds the processed material; an imaging unit that images the processed material held by the holding surface; a processing unit that processes the processed material held by the holding surface; and a control unit. The control unit determines whether or not a structure of the processed material is formed on the basis of a result obtained by imaging the processed material by the imaging unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a processing device that processes a workpiece, and a method for determining the type of workpiece. [Background technology]

[0002] The device chip manufacturing process uses a wafer in which devices are formed in multiple areas defined by multiple streets (planned division lines) arranged in a grid pattern. By dividing this wafer along the streets, multiple device chips, each equipped with a device, are obtained. The device chips are incorporated into various electronic devices, such as mobile phones and personal computers.

[0003] For example, a cutting device is used to divide the wafer. The cutting device includes a chuck table that holds the workpiece and a cutting unit that cuts the workpiece, and an annular cutting blade is attached to the cutting unit. The wafer is held on the chuck table, and the cutting blade is rotated to cut into the wafer, thereby cutting and dividing the wafer (see Patent Document 1).

[0004] Furthermore, in recent years, with the miniaturization of electronic devices, there has been a demand for thinner device chips. Therefore, a grinding device is sometimes used to thin wafers before they are divided. The grinding device includes a chuck table for holding the workpiece and a grinding unit for grinding the workpiece, and the grinding unit is equipped with an annular grinding wheel including a grinding stone. The wafer is held by the chuck table, and the grinding stone is brought into contact with the wafer while the chuck table and grinding wheel are rotated, thereby grinding and thinning the wafer (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-159823 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-90389 Summary of the Invention [Problem to be solved by the invention]

[0006] When a workpiece on which a structure such as a device is formed is divided using a processing device such as a cutting device, it is necessary to identify the positions of the streets set on the workpiece and process the workpiece along the streets. Therefore, before processing the workpiece, an image of the workpiece is captured by an imaging unit provided in the processing device to detect the positions of the structures formed on the workpiece, and a process is performed to identify the positions of the streets based on the positions of the structures.

[0007] Furthermore, the processing equipment is highly versatile and can also be used to process workpieces on which no device or other structures are formed. For example, when manufacturing a stacked device chip comprising multiple stacked device chips, individual silicon wafer pieces (silicon chips) may be provided between the stacked device chips as intermediate layers that separate the device chips. These silicon chips are formed by dividing a silicon wafer on which no devices are formed using the processing equipment.

[0008] When a workpiece without a structure is processed by a processing device, the processing area cannot be identified based on the position of the structure. Therefore, processing conditions (position, spacing, etc. of the processing area) are selected in advance according to the shape, dimensions, etc. of the workpiece, and input and set in the processing device. Then, the processing device omits the process of capturing an image of the workpiece with an imaging unit to detect the position of the structure, and processes the workpiece according to the set processing conditions.

[0009] As described above, the processing device operates in an operation mode in which imaging is performed to detect the position of a structure (structure detection mode) or an operation mode in which imaging to detect the position of a structure is not performed (structure non-detection mode), depending on whether or not a structure is formed on the workpiece, which is the object to be processed. However, if a workpiece on which a structure is formed is mistakenly set in a processing device operating in the structure non-detection mode, processing of the workpiece on which a structure is formed continues without detecting the position of the structure. As a result, processing is performed on the workpiece without regard to the arrangement of the structures, resulting in a defective product.

[0010] The present invention has been made in view of the above problem, and has an object to provide a processing device and a method for determining a workpiece that can prevent erroneous processing of the workpiece. [Means for solving the problem]

[0011] According to one aspect of the present invention, a processing device for processing a workpiece includes a chuck table having a holding surface for holding the workpiece, an imaging unit for imaging the workpiece held on the holding surface, a processing unit for processing the workpiece held on the holding surface, and a control unit, and the control unit determines a position of the workpiece based on the image of the workpiece captured by the imaging unit. device A processing device is provided that determines whether or not a defect is formed.

[0012] Preferably, the control unit is configured to: when the image capturing unit captures an image of the workpiece held on the holding surface while moving the image capturing unit toward or away from the holding surface, if the image capturing unit is not in focus, device If the imaging unit is in focus, it is determined that the workpiece is not formed. device Preferably, the processing device determines that the control unit is device When it is determined that the workpiece is not formed, the processing unit processes the workpiece, and the control unit processes the workpiece. device If it is determined that a gap is formed, an error is generated.

[0013] According to another aspect of the present invention, Determining whether or not a device is formed on a workpiece A method for determining a workpiece, comprising: a holding step of holding the workpiece on a holding surface of a chuck table; and, after the holding step, determining whether the workpiece is a target object based on a result of imaging the workpiece with an imaging unit. device and determining whether or not a defect is formed.

[0014] Preferably, in the determining step, the image capturing unit captures an image of the workpiece held on the holding surface while moving the image capturing unit toward or away from the holding surface, and if the image capturing unit cannot focus on the workpiece, the image capturing unit captures an image of the workpiece. device If the imaging unit is in focus, it is determined that the workpiece is not formed. device Preferably, in the method for determining a workpiece, after the determining step, the workpiece is determined to have a device If it is determined that the workpiece is not formed, the workpiece is machined, and in the determination step, device The method further includes a processing step of issuing an error if it is determined that the .gtoreq..times ... [Effects of the Invention]

[0015] In a processing device and a method for determining a workpiece according to one aspect of the present invention, whether or not a structure is formed on the workpiece is determined based on the result of imaging the workpiece with an imaging unit. This makes it possible to avoid a workpiece on which a structure is formed being mistakenly processed as a workpiece on which no structure is formed, thereby preventing the occurrence of defective products. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. [Figure 2] FIG. 2(A) is a perspective view showing a workpiece on which a structure is formed, and FIG. 2(B) is a perspective view showing a workpiece on which no structure is formed. [Figure 3] FIG. 2 is a block diagram showing a control unit. [Figure 4] 10 is a flowchart showing a method for determining a workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment according to one aspect of the present invention will be described below with reference to the accompanying drawings. First, an example of the configuration of a processing device according to this embodiment will be described. FIG. 1 is a perspective view showing a cutting device 2. The cutting device 2 is a processing device that performs cutting on a workpiece. In FIG. 1, the X-axis direction (processing feed direction, first horizontal direction, front-rear direction) and the Y-axis direction (indexing feed direction, second horizontal direction, left-right direction) are perpendicular to each other. Furthermore, the Z-axis direction (cutting direction, vertical direction, up-down direction, height direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0018] The cutting device 2 includes a base 4 that supports or houses each of the components that make up the cutting device 2. A moving unit (moving mechanism) 6 is provided on the upper surface of the base 4. The moving unit 6 includes a pair of X-axis guide rails 8 that are arranged along the X-axis direction.

[0019] A flat X-axis moving table 10 is slidably mounted on the pair of X-axis guide rails 8. A nut portion (not shown) is provided on the lower surface (back surface) side of the X-axis moving table 10. An X-axis ball screw 12, which is arranged along the X-axis direction between the pair of X-axis guide rails 8, is threadedly engaged with this nut portion. An X-axis pulse motor 14 is connected to the end of the X-axis ball screw 12. When the X-axis pulse motor 14 rotates the X-axis ball screw 12, the X-axis moving table 10 moves in the X-axis direction along the X-axis guide rails 8.

[0020] A cylindrical table base 16 is provided on the upper surface (surface) of the X-axis moving table 10. The table base 16 supports a chuck table (holding table) 18 that holds a workpiece, which is an object to be machined by the cutting device 2. The upper surface of the chuck table 18 is a flat surface that is roughly parallel to the horizontal plane (XY plane), and forms a holding surface 18a that holds the workpiece. The holding surface 18a is connected to a suction source (not shown), such as an ejector, via a flow path (not shown), a valve (not shown), and the like, formed inside the chuck table 18.

[0021] The chuck table 18 moves along the X-axis direction by moving the X-axis moving table 10 in the X-axis direction using the moving unit 6. A rotary drive source (not shown) such as a motor is connected to the chuck table 18, and this rotary drive source rotates the chuck table 18 around a rotation axis that is roughly parallel to the Z-axis direction.

[0022] A water case 20 that temporarily stores waste liquid generated during cutting is provided around the X-axis moving table 10. The waste liquid stored inside the water case 20 is discharged to the outside of the cutting device 2 via a drain (not shown) or the like.

[0023] A gate-shaped support structure 22 is provided on the upper surface of the base 4 so as to straddle the moving unit 6. A pair of moving units (moving mechanisms) 24 are provided on both ends of the front side of the support structure 22. Specifically, a pair of Y-axis guide rails 26 are fixed to the front side of the support structure 22 along the Y-axis direction.

[0024] A flat Y-axis moving plate 28 provided on each of the pair of moving units 24 is slidably mounted on the pair of Y-axis guide rails 26. In addition, a pair of Y-axis ball screws 30 is provided between the pair of Y-axis guide rails 26 along the Y-axis direction.

[0025] A nut portion (not shown) is provided on the rear surface (back surface) side of the Y-axis moving plate 28. A Y-axis ball screw 30 is threadedly engaged with this nut portion. A Y-axis pulse motor 32 is connected to each end of the pair of Y-axis ball screws 30. When the Y-axis pulse motor 32 rotates the Y-axis ball screw 30, the Y-axis moving plate 28 moves in the Y-axis direction along the Y-axis guide rail 26.

[0026] A pair of Z-axis guide rails 34 are fixed along the Z-axis to the front (surface) side of the Y-axis moving plate 28. A flat Z-axis moving plate 36 is slidably mounted on the pair of Z-axis guide rails 34.

[0027] A nut portion (not shown) is provided on the rear surface (back surface) side of the Z-axis moving plate 36. A Z-axis ball screw 38, which is disposed along the Z-axis direction between a pair of Z-axis guide rails 34, is threadedly engaged with this nut portion. A Z-axis pulse motor 40 is also connected to the end of the Z-axis ball screw 38. When the Z-axis pulse motor 40 rotates the Z-axis ball screw 38, the Z-axis moving plate 36 moves (up and down) in the Z-axis direction along the Z-axis guide rails 34.

[0028] A machining unit (cutting unit) 42 that performs cutting on a workpiece is fixed to the lower part of the Z-axis moving plate 36. The machining unit 42 has a housing 44 formed in a hollow cylindrical shape. The housing 44 contains a cylindrical spindle 46 (see FIG. 3) that is arranged along the Y-axis direction. A tip end (one end) of the spindle 46 is exposed from the housing 44, and a rotation drive source (not shown) such as a motor that rotates the spindle 46 is connected to a base end (other end) of the spindle 46.

[0029] An annular cutting blade 48 that cuts the workpiece is attached to the tip of the spindle 46. The cutting blade 48 may be, for example, a hub-type cutting blade (hub blade). The hub blade is formed by integrating an annular base made of metal or the like with an annular cutting edge formed along the outer periphery of the base. The cutting edge of the hub blade is made of an electroformed grinding stone or the like containing abrasive grains made of diamond or the like and a binder such as a nickel-plated layer that secures the abrasive grains in place. However, a washer-type cutting blade (washer blade) may also be used as the cutting blade 48. A washer blade is made up of only an annular cutting edge that contains abrasive grains and a binder made of metal, ceramics, resin, or the like that secures the abrasive grains in place.

[0030] The cutting blade 48 rotates around a rotation axis that is roughly parallel to the Y-axis direction by power transmitted from the rotation drive source via the spindle 46. The processing unit 42 then cuts the workpiece held by the chuck table 18 by rotating the cutting blade 48 and causing the cutting blade 48 to cut into the workpiece.

[0031] The machining unit 42 is also provided with a nozzle 50 that supplies a liquid (cutting fluid) such as pure water. During cutting, the cutting fluid is supplied from the nozzle 50 to the workpiece and the cutting blade 48. This cools the workpiece and the cutting blade 48 and washes away chips (cutting chips) generated by cutting the workpiece.

[0032] A pair of cutting blades 48 are attached to the pair of processing units 42 so as to face each other. That is, the cutting device 2 is a so-called facing dual spindle type cutting device. However, the number of cutting units provided in the cutting device 2 may be one.

[0033] An imaging unit 52 that captures an image of the workpiece is provided adjacent to the processing unit 42. The imaging unit 52 includes an image sensor such as a CCD (Charged-Coupled Device) sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor, and captures an image of the upper surface of the workpiece held by the chuck table 18. For example, a visible light camera or an infrared camera is used as the imaging unit 52. The image acquired by the imaging unit 52 is used for aligning the workpiece and the processing unit 42, etc.

[0034] The moving unit 24 moves the machining unit 42 and the imaging unit 52 toward and away from the holding surface 18a of the chuck table 18. Specifically, when the moving unit 24 moves the Y-axis moving plate 28 along the Y-axis direction, the chuck table 18, the machining unit 42, and the imaging unit 52 move relatively along the Y-axis direction. Furthermore, when the moving unit 24 moves (raise and lower) the Z-axis moving plate 36 along the Z-axis direction, the chuck table 18, the machining unit 42, and the imaging unit 52 move relatively along the Z-axis direction.

[0035] A display unit (display section, display device) 54 that displays information related to the cutting device 2 is provided on the front side of the cutting device 2. The display unit 54 is made up of various displays, and displays information related to the processing of the workpiece (processing conditions, processing status, etc.). For example, a touch panel display is used as the display unit 54. In this case, the display unit 54 also functions as an input unit (input section, input device) for inputting information to the cutting device 2, and the operator can input information to the cutting device 2 by touching the display unit 54. In other words, the display unit 54 functions as a user interface.

[0036] An alarm unit (alarm section, alarm device) 56 that notifies the operator of information is provided on the top of the cutting device 2. For example, an indicator light (warning light) is provided as the alarm unit 56, and when an abnormality occurs in the cutting device 2, the indicator light lights up or flashes to signal an error. However, there is no limitation on the type of alarm unit 56. For example, the alarm unit 56 may be a speaker that notifies the operator of information by sound or voice.

[0037] Furthermore, the cutting device 2 includes a control unit (controller, controller) 58 that controls the cutting device 2. The control unit 58 is connected to each of the components that make up the cutting device 2 (the moving unit 6, the chuck table 18, the moving unit 24, the processing unit 42, the imaging unit 52, the display unit 54, the notification unit 56, etc.).

[0038] The control unit 58 outputs control signals to each component of the cutting device 2, thereby controlling the operation of each component and operating the cutting device 2. For example, the control unit 58 is configured by a computer, and includes a processor such as a CPU (Central Processing Unit) that performs calculations necessary for operating the cutting device 2, and memories such as a ROM (Read Only Memory) and RAM (Random Access Memory) that store various information (data, programs, etc.) used for operating the cutting device 2.

[0039] Next, we will explain specific examples of workpieces to be machined by the cutting device 2. Figures 2(A) and 2(B) show two types of workpieces. Figure 2(A) is a perspective view showing workpiece 11 on which a structure is formed, and Figure 2(B) is a perspective view showing workpiece 17 on which no structure is formed.

[0040] 2(A) is a disk-shaped wafer made of a semiconductor material such as silicon, and includes a front surface (first surface) 11a and a back surface (second surface) 11b that are generally parallel to each other. The workpiece 11 is divided into a plurality of rectangular regions by streets (planned division lines) 13 that are arranged in a grid pattern so as to intersect with each other.

[0041] Structures 15 are formed on the surface 11a of each of the multiple regions partitioned by the streets 13. That is, a pattern formed by the multiple structures 15 appears on the surface 11a of the workpiece 11. For example, the structures 15 are devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices. By dividing the workpiece 11 along the streets 13 using the cutting device 2, chips (device chips) each including a structure 15 (device) are manufactured.

[0042] However, there are no limitations on the material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 17 may be a wafer (substrate) made of a material such as a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramics, resin, or metal. There are also no limitations on the type, number, shape, structure, size, arrangement, etc. of the structures 15 formed on the workpiece 11. For example, the structures 15 may be electrodes, wiring, etc.

[0043] 2(B) is a disk-shaped wafer made of a semiconductor material such as silicon, and includes a front surface (first surface) 17a and a back surface (second surface) 17b that are generally parallel to each other. The front surface 17a and the back surface 17b of the workpiece 17 have been subjected to a planarization process and a mirror-finish process. That is, the front surface 17a and the back surface 17b are flat and mirror-finished.

[0044] The cutting device 2 cuts and divides the workpiece 17 into a lattice pattern, thereby producing chips (silicon chips) corresponding to the individual pieces of the workpiece 17. For example, silicon chips are used to produce stacked device chips having a plurality of stacked device chips. Specifically, silicon chips may be provided between stacked device chips as intermediate layers that separate the device chips from one another.

[0045] However, there are no limitations on the material, shape, structure, size, etc. of the workpiece 17. Examples of materials for the workpiece 17 are the same as those for the workpiece 11. For example, the workpiece 17 may be a transparent or translucent body made of a material such as quartz glass, borosilicate glass, plastic, sapphire, calcium fluoride, lithium fluoride, or magnesium fluoride. In this case, transparent or translucent parts (optical parts, etc.) are manufactured by dividing the workpiece 17.

[0046] As described above, workpiece 11 and workpiece 17 differ in whether or not a structure such as a device is formed thereon. Cutting device 2 (see FIG. 1) can be used to process different types of workpieces such as workpieces 11 and 17, and cuts the workpieces under processing conditions set for each type of workpiece.

[0047] For ease of handling (transporting, holding, etc.) the workpiece 11, the workpiece 11 is supported by an annular frame 19. The frame 19 is an annular member made of a metal such as SUS (stainless steel). A cylindrical opening 19a having a diameter larger than that of the workpiece 11 is provided in the center of the frame 19 so as to penetrate the frame 19 in the thickness direction.

[0048] Tape (dicing tape) 21 is attached to the workpiece 11 and the frame 19. The tape 21 includes a circular film-like substrate and an adhesive layer (glue layer) provided on the substrate. For example, the substrate is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate. The adhesive layer is made of an epoxy-based, acrylic-based, or rubber-based adhesive. The adhesive layer may be an ultraviolet-curable resin that hardens when exposed to ultraviolet light.

[0049] With the workpiece 11 placed inside the opening 19a of the frame 19, the central portion of the tape 21 is attached to the back surface 11b of the workpiece 11, and the outer periphery of the tape 21 is attached to the frame 19. In this way, the workpiece 11 is supported by the frame 19 via the tape 21.

[0050] When cutting the workpiece 11 with the cutting device 2, the workpiece 11 is held by the chuck table 18 (see FIG. 3). Specifically, first, the workpiece 11 is placed on the holding surface 18a via the tape 21. Furthermore, a plurality of clamps 18b are provided around the periphery of the chuck table 18, and the frame 19 is gripped and fixed by the plurality of clamps 18b. Then, when the suction force (negative pressure) of the suction source is applied to the holding surface 18a, the workpiece 11 is sucked and held by the chuck table 18 via the tape 21.

[0051] Next, the chuck table 18 is rotated to align the length direction of the predetermined street 13 with the X-axis direction. Also, the position of the processing unit 42 in the Y-axis direction is adjusted so that the cutting blade 48 is positioned on an extension line of the predetermined street 13. Furthermore, the height of the processing unit 42 is adjusted so that the lower end of the cutting blade 48 is positioned below the back surface 11b of the workpiece 11 (the upper surface of the tape 21).

[0052] Then, while rotating the cutting blade 48, the chuck table 18 is moved along the X-axis direction. As a result, the chuck table 18 and the cutting blade 48 move relatively along the X-axis direction (processing feed), and the cutting blade 48 cuts into the workpiece 11 along the streets 13. As a result, the workpiece 11 is cut and divided along the streets 13. Thereafter, by repeating the same procedure, the workpiece 11 is divided along all of the streets 13, and a plurality of chips each having a structure 15 are obtained.

[0053] When cutting workpiece 17 (see FIG. 2(B)) with cutting device 2, workpiece 17, like workpiece 11, is supported by frame 19 via tape 21 and held by chuck table 18 (see FIG. 3). Then, cutting blade 48 is rotated to cut into workpiece 17, thereby dividing workpiece 17 into a plurality of chips.

[0054] Here, when the workpiece 11 (see FIG. 2(A)) on which the structure 15 is formed is machined by the cutting device 2, the workpiece 11 held by the chuck table 18 is imaged by the imaging unit 52 before machining the workpiece 11, and the position of the structure 15 is detected. In addition, the position of the street 13 is identified based on the position of the structure 15, and the positional relationship between the workpiece 11 and the cutting blade 48 is adjusted so that the cutting blade 48 cuts along the street 13. In other words, the cutting device 2 operates in an operation mode (structure detection mode) in which imaging is performed to detect the position of the structure.

[0055] On the other hand, when using the cutting device 2 to process a workpiece 17 (see FIG. 2(B)) on which no structures are formed, it is not possible to identify the processing area based on the position of the structures. For this reason, processing conditions (position, spacing, etc. of the processing area) are selected in advance according to the shape, dimensions, etc. of the workpiece 17, and are input and set in the cutting device 2. Then, the cutting device 2 cuts the workpiece 17 according to the set processing conditions. In other words, the cutting device 2 operates in an operation mode (structure non-detection mode) in which imaging for detecting the position of the structures is not performed.

[0056] However, when the cutting device 2 is set to the structure non-detection mode to process a workpiece 17 on which no structures are formed, if a workpiece 11 on which structures 15 are formed is mistakenly set in the cutting device 2, cutting of the workpiece 11 will continue without detecting the positions of the structures 15 and identifying the streets 13. As a result, the workpiece 11 will be processed without regard for the arrangement of the structures 15, resulting in a defective product.

[0057] Therefore, in this embodiment, even when the cutting device 2 is operating in the structure non-detection mode, the image capturing unit 52 captures an image of the workpiece before the workpiece is processed by the processing unit 42, and it is determined whether or not a structure has been formed on the workpiece. This makes it possible to avoid processing the workpiece 11 on which the structure 15 has been formed as the workpiece 17 on which the structure has not been formed, thereby preventing the occurrence of defective products.

[0058] The operation of the cutting device 2 during cutting processing is controlled by a control unit 58. Fig. 3 is a block diagram showing the control unit 58. In addition to a block showing the functional configuration of the control unit 58, Fig. 3 also shows a schematic diagram of some of the components of the cutting device 2 (the chuck table 18, the moving unit 24, the processing unit 42, the imaging unit 52, the display unit 54, and the notification unit 56).

[0059] The control unit 58 includes a processing unit 60 that executes processing necessary for the operation of the cutting device 2, and a storage unit 70 that stores information (data, programs, etc.) used for processing by the processing unit 60. The processing unit 60 also includes a determination unit 62 that determines whether or not a structure is formed on the workpiece, and a drive control unit 68 that drives the components of the cutting device 2 based on the result of the determination by the determination unit 62.

[0060] When the workpiece (workpiece 11 or workpiece 17) is held by the chuck table 18, the imaging unit 52 captures an image of the workpiece and obtains an image (captured image) of the workpiece. Then, the determination unit 62 determines whether or not a structure is formed on the workpiece based on the result of capturing the image of the workpiece by the imaging unit 52.

[0061] Specifically, the determination unit 62 includes a contrast detection unit 64 that detects the contrast of the captured image. The captured image acquired by the imaging unit 52 is input to the contrast detection unit 64. The contrast detection unit 64 then performs image processing on the captured image to calculate the contrast of the captured image. The contrast detection unit 64 also stores the calculated contrast in a contrast storage unit 72 included in the storage unit 70.

[0062] For example, the imaging unit 52 is raised and lowered along the Z-axis direction by the moving unit 24, and the imaging unit 52 is moved toward or away from the holding surface 18a while the imaging unit 52 continuously captures images of the workpiece held on the holding surface 18a. As a result, multiple captured images acquired under different conditions of the positional relationship between the focal point of the imaging unit 52 and the workpiece are sequentially input to the contrast detection unit 64. The contrast detection unit 64 then calculates the contrast of each captured image and stores the results in the contrast storage unit 72.

[0063] The determination unit 62 also includes a focus determination unit 66 that determines whether or not the imaging unit 52 is in focus. The focus determination unit 66 determines whether or not the imaging unit 52 is in focus when the imaging unit 52 images the workpiece, based on the contrast of the captured image (focus determination).

[0064] The contrast of the captured image acquired by the imaging unit 52 is maximum when the imaging unit 52 is focused on the subject, and is low when the imaging unit 52 is not focused on the subject. Therefore, for example, the focus determination unit 66 determines that the imaging unit 52 is focused on the subject when the contrast of the captured image is at a maximum value and is equal to or greater than a predetermined threshold.

[0065] Specifically, the contrasts of a plurality of captured images stored in a contrast storage unit 72 are input to the focus determination unit 66. The storage unit 70 also includes a threshold storage unit 74 that stores a threshold value for the contrast of the captured images, and a predetermined threshold value stored in the threshold storage unit 74 is input to the focus determination unit 66. Then, the focus determination unit 66 determines whether or not the transition of contrast includes a maximum value, and whether or not the maximum value is equal to or greater than the threshold value.

[0066] If the transition of contrast includes a maximum value and the maximum value is equal to or greater than the threshold value, the focus determination unit 66 determines that the focus of the imaging unit 52 was on the workpiece when the imaging unit 52 captured the image of the workpiece. On the other hand, if the transition of contrast does not include a maximum value or the maximum value is less than the threshold value, the focus determination unit 66 determines that the focus of the imaging unit 52 was not on the workpiece when the imaging unit 52 captured the image of the workpiece.

[0067] For example, when the workpiece 11 (see FIG. 2(A)) is held by the chuck table 18, the imaging unit 52 continuously captures images of the surface 11a side of the workpiece 11 while moving toward or away from the workpiece 11. Then, at the timing when the focus of the imaging unit 52 matches the structure 15 formed on the surface 11a of the workpiece 11, a captured image is acquired in which the contrast has a maximum value equal to or greater than a threshold value. In this case, the focus determination unit 66 determines that the focus of the imaging unit 52 matches the surface 11a side of the workpiece 11 and that a structure is formed on the workpiece 11.

[0068] On the other hand, when the workpiece 17 (see FIG. 2B) is held by the chuck table 18, the imaging unit 52 continuously images the surface 17a of the workpiece 17 while moving toward or away from the workpiece 17. However, the surface 17a of the workpiece 17 is mirror-finished and has no structures formed thereon. Therefore, there is no subject on the surface 17a of the workpiece 17 that the imaging unit 52 can focus on. As a result, no maximum contrast value is detected in the captured image, and even if a maximum value exists, it is lower than the threshold value. In this case, the focus determination unit 66 determines that the imaging unit 52 is not focused on the surface 17a of the workpiece 17 and that no structures are formed on the workpiece 17.

[0069] As described above, the determination unit 62 determines whether or not a structure is formed on the workpiece based on the focus determination. Note that, although the focus determination based on the contrast of the captured image has been described above, other methods may also be used for the focus determination.

[0070] The result of the determination by the determination unit 62 is output to the drive control unit 68. Specifically, the focus determination unit 66 outputs a signal indicating that a structure is formed on the workpiece or a signal indicating that a structure is not formed on the workpiece as the determination result to the drive control unit 68. Then, the drive control unit 68 controls the operation of each component of the cutting device 2 based on the determination result of the determination unit 62.

[0071] For example, when the cutting device 2 processes the workpiece 17 (see FIG. 2(B)), the cutting device 2 operates in a structure non-detection mode, and the workpiece 17 is held by the chuck table 18. In addition, a low-contrast image of the workpiece 17 is acquired, and the determination unit 62 determines that no structure is formed on the workpiece 17.

[0072] The drive control unit 68, to which the determination result of the determination unit 62 has been input, outputs control signals to the components of the cutting device 2 (the moving unit 6, the chuck table 18, the moving unit 24, the processing unit 42, etc.), and causes the cutting blade 48 to cut into the workpiece 17 under preset conditions. As a result, the workpiece 17 is processed by the processing unit 42.

[0073] Furthermore, if the workpiece 11 (see FIG. 2(A)) is set in the cutting device 2 by mistake, the workpiece 11 is held by the chuck table 18 and is imaged by the imaging unit 52. In this case, an image of the workpiece 11 in which the contrast has a maximum value equal to or greater than the threshold is acquired, and the determination unit 62 determines that a structure has been formed on the workpiece 11.

[0074] Then, the drive control unit 68, to which the determination result of the determination unit 62 has been input, outputs a control signal to, for example, the display unit 54 and the notification unit 56, and issues an error notifying that an unintended workpiece has been set in the cutting device 2. For example, the drive control unit 68 causes the display unit 54 to display a message notifying the occurrence and content of an abnormality, and causes the notification unit 56 to light up or flash. This notifies the operator that an incorrect workpiece has been set in the cutting device 2.

[0075] Next, a specific example of a method for determining the type of workpiece using the above-described cutting device 2 will be described. Fig. 4 is a flowchart showing the method for determining the type of workpiece. Below, a case where cutting of a workpiece 17 (see Fig. 2(B)) by the cutting device 2 is scheduled and the cutting device 2 is set to the structure non-detection mode will be described with reference to Figs. 3 and 4.

[0076] First, a holding step is performed in which the workpiece is held by the holding surface 18a of the chuck table 18 (step S1). When the workpiece 17 (see FIG. 2(B)) is set in the cutting device 2 as planned, the workpiece 17 is transported to the chuck table 18. Then, the workpiece 17 is suction-held by the chuck table 18 so that the front surface 17a is exposed upward and the back surface 17b (the tape 21 side) faces the holding surface 18a.

[0077] On the other hand, if the workpiece 11 (see FIG. 2(A)) is mistakenly set on the cutting device 2, the workpiece 11 is transported to the chuck table 18. Then, the workpiece 11 is sucked and held by the chuck table 18 so that the front surface 11a side (the structure 15 side) is exposed upward and the back surface 11b side (the tape 21 side) faces the holding surface 18a.

[0078] Next, a determination step is carried out in which it is determined whether or not a structure has been formed on the workpiece based on the result of imaging the workpiece with the imaging unit 52 (step S2). In the determination step, the imaging unit 52 is raised and lowered along the Z-axis direction by the moving unit 24, and the imaging unit 52 is moved toward or away from the holding surface 18a, while the imaging unit 52 continuously images the workpiece held on the holding surface 18a. If the imaging unit 52 is not in focus during imaging, it is determined that no structure has been formed on the workpiece (YES in step S3). On the other hand, if the imaging unit 52 is in focus during imaging, it is determined that a structure has been formed on the workpiece (NO in step S3).

[0079] Specifically, when the workpiece is imaged multiple times by the imaging unit 52 while the imaging unit 52 is raised and lowered, multiple images with different contrasts are obtained. The multiple images are then input to the determination unit 62 of the control unit, and the contrast of each image is calculated by the contrast detection unit 64. The calculated contrast values ​​are then stored in the contrast storage unit 72.

[0080] Next, the contrast of the captured image is input from the contrast storage unit 72 to the focus determination unit 66, and the contrast threshold is input from the threshold storage unit 74 to the focus determination unit 66. Then, the focus determination unit 66 determines whether the focus of the imaging unit 52 is on the workpiece based on the transition of the contrast of the captured image and the threshold.

[0081] Here, when the workpiece 17 (see FIG. 2B) is held on the chuck table 18 as planned, even if the imaging unit 52 is raised and lowered, the imaging unit 52 will not be focused on the surface 17a of the workpiece 17. Therefore, the focus determination unit 66 determines that no structure has been formed on the workpiece, and outputs the determination result to the drive control unit 68.

[0082] On the other hand, if the workpiece 11 (see FIG. 2A) is mistakenly held on the chuck table 18, an image in which the contrast takes a maximum value equal to or greater than the threshold value is acquired at the timing when the focus of the imaging unit 52 is aligned with the structure 15 formed on the surface 11a of the workpiece 11. Therefore, the focus determination section 66 determines that a structure is formed on the workpiece, and the determination result is output to the drive control section 68.

[0083] In the determination step, two or more different regions of the workpiece may be imaged by the imaging unit 52. Specifically, after the first imaging, the position of the chuck table 18 in the X-axis direction or the position of the imaging unit 52 in the Y-axis direction is changed, and a second imaging is performed. Thereafter, the same process is repeated to perform the third and subsequent imaging. In this way, by imaging multiple locations included in the workpiece, it is possible to prevent structures from being overlooked.

[0084] The determination of the presence or absence of a structure in the above determination step is simpler than the processing performed in the structure detection mode (detection of the position of the structure 15 and identification of the street 13). Therefore, even if a determination step is added in the structure non-detection mode, the series of handling steps of the workpiece by the cutting device 2 will not be significantly delayed.

[0085] Next, a process is carried out according to the result of the determination in the determination step (processing step). For example, if it is determined in the determination step that no structure is formed on the workpiece, the workpiece is processed as usual. On the other hand, if it is determined in the determination step that a structure is formed on the workpiece, an error is transmitted.

[0086] If the workpiece 17 is held on the chuck table 18 as expected, the determination unit 62 outputs a determination result indicating that no structure is formed on the workpiece to the drive control unit 68 (YES in step S3). In this case, the drive control unit 68 outputs control signals to the moving unit 6, the chuck table 18, the moving unit 24, the processing unit 42, etc., to cause the cutting blade 48 to cut into the workpiece 17 and the processing unit 42 to process the workpiece 17 (step S4).

[0087] On the other hand, if the workpiece 11 is mistakenly held on the chuck table 18, a determination result indicating that a structure has been formed on the workpiece is output from the determination unit 62 to the drive control unit 68 (NO in step S3). In this case, the drive control unit 68 stops the processing of the workpiece 11 by the processing unit 42. In addition, the drive control unit 68 outputs a control signal to the display unit 54 and the notification unit 56, causing the cutting device 2 to issue an error informing that an incorrect workpiece has been set (step S5).

[0088] When the cutting device 2 issues an error signal, measures are taken to resolve the abnormality (step S6). For example, an operator who recognizes the error operates the cutting device 2 and removes the workpiece 11 that is mistakenly held by the chuck table 18 from the cutting device 2. Alternatively, the cutting device 2 automatically removes the workpiece 11 from the chuck table 18 without processing it. Thereafter, the next workpiece is transported to the chuck table 18 (step S1).

[0089] The operation of the control unit 58 in the above series of steps is realized by executing a program stored in a storage unit 70 (memory). Specifically, a program describing the processing in steps S1 to S5 is stored in the storage unit 70. The control unit 58 reads and executes the program from the storage unit 70, thereby causing the cutting device 2 to transport, judge, process, and so on the workpiece 17.

[0090] As described above, in the cutting device 2 and the workpiece determination method according to this embodiment, it is determined whether or not a structure is formed on the workpiece based on the result of capturing an image of the workpiece with the imaging unit 52. This makes it possible to avoid workpiece 11 on which structure 15 is formed being mistakenly processed as workpiece 17 on which no structure is formed, thereby preventing the occurrence of defective products.

[0091] In this embodiment, the determination unit 62 determines the type of workpiece based on whether the imaging unit 52 is in focus, but the determination unit 62 may determine the type of workpiece using other methods. For example, the determination unit 62 may determine whether a structure is formed on the workpiece by pattern matching, which compares the image of the workpiece acquired by the imaging unit 52 with a reference image prepared in advance.

[0092] Specifically, before the workpiece is machined by the cutting device 2, a reference image is acquired in advance and stored in the memory unit 70 of the control unit 58. For example, the reference image is acquired by holding the workpiece 11 (see FIG. 2(A)) on which the structure 15 is formed on the chuck table 18, and imaging the front surface 11a side of the workpiece 11 with the imaging unit 52 while focusing the imaging unit 52 on the structure 15. In other words, the reference image corresponds to an image of the workpiece on which the device is formed.

[0093] Thereafter, the workpiece, which is the object to be machined, is held by the chuck table 18, and the imaging unit 52 acquires an image of the workpiece. The determination unit 62 then performs pattern matching to compare the captured image with the reference image and determine the type of workpiece. Specifically, if the captured image and the reference image match or are similar, the determination unit 62 determines that a structure is formed on the workpiece, and if the captured image and the reference image are dissimilar, the determination unit 62 determines that no structure is formed on the workpiece.

[0094] Furthermore, the timing for determining the type of workpiece can be set freely. For example, when a cassette containing multiple workpieces of the same type is set in the cutting device 2, the determination is performed on the first workpiece transported from the cassette to the chuck table 18. However, there is no limit to the frequency of the determination, and the determination may be performed, for example, every time a workpiece is transported to the chuck table 18.

[0095] Furthermore, the determination of the type of workpiece according to this embodiment can also be performed in processing devices other than the cutting device 2. For example, the determination of the type of workpiece may be performed in a laser processing device that performs laser processing on the workpiece. The laser processing device includes a chuck table that holds the workpiece and a processing unit (laser irradiation unit) that irradiates the workpiece with a laser beam. The laser irradiation unit includes a laser oscillator that oscillates a laser of a predetermined wavelength and a condenser that condenses the laser beam emitted from the laser oscillator. Laser processing is performed on the workpiece by irradiating the workpiece with a laser beam from the laser irradiation unit.

[0096] The laser processing device includes a control unit that controls each component of the laser processing device, similar to the cutting device 2. The control unit of the laser processing device is configured similarly to the control unit 58 (see FIG. 3). This makes it possible to determine whether or not a structure such as a device is formed on the workpiece processed by the laser processing device.

[0097] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0098] 11 Workpiece 11a Surface (first side) 11b Back side (2nd side) 13th Street (Planned division line) 15 Structures 17 Workpiece 17a Front (first side) 17b Back side (2nd side) 19 frames 19a aperture 21 Tape (dicing tape) 2 Cutting equipment 4 Foundation 6. Mobile unit (mobile mechanism) 8 X-axis guide rail 10 X-axis moving table 12 X-axis ball screw 14 X-axis pulse motor 16 Table Base 18 Chuck table (holding table) 18a Holding surface 18b clamp 20 Water Case 22 Support structure 24 Mobile unit (mobile mechanism) 26 Y-axis guide rail 28 Y-axis moving plate 30 Y-axis ball screw 32 Y-axis pulse motor 34 Z-axis guide rail 36 Z-axis moving plate 38 Z-axis ball screw 40 Z-axis pulse motor 42 Processing unit (cutting unit) 44 Housing 46 Spindle 48 Cutting Blade 50 nozzles 52 Imaging unit 54 Display unit (display unit, display device) 56 Alarm unit (alarm unit, alarm device) 58 Control unit (control unit, control device) 60 Processing section 62 Judgment section 64 Contrast detection section 66 Focus determination unit 68 Drive control unit 70 Memory section 72 Contrast memory section 74 Threshold memory unit

Claims

1. A processing device for processing a workpiece, a chuck table having a holding surface for holding the workpiece; an imaging unit that images the workpiece held on the holding surface; a processing unit that processes the workpiece held on the holding surface; a control unit; The control unit determines whether or not a device is formed on the workpiece based on the result of imaging the workpiece by the imaging unit.

2. The processing apparatus according to claim 1, characterized in that when the control unit images the workpiece held on the holding surface with the imaging unit while moving the imaging unit closer to or away from the holding surface, if the imaging unit is out of focus, it determines that a device is not formed on the workpiece, and if the imaging unit is in focus, it determines that a device is formed on the workpiece.

3. The processing apparatus according to claim 1 or 2, characterized in that if the control unit determines that no device is formed on the workpiece, the processing unit processes the workpiece, and if the control unit determines that a device is formed on the workpiece, an error is issued.

4. A method for determining whether or not a device is formed on a workpiece, comprising: a holding step of holding the workpiece on a holding surface of a chuck table; A method for determining a workpiece, characterized in that it includes, after the holding step, a determination step of determining whether or not a device is formed on the workpiece based on the results of imaging the workpiece with an imaging unit.

5. The method for determining a workpiece according to claim 4, characterized in that in the determination step, the imaging unit images the workpiece held on the holding surface while moving the imaging unit closer to or away from the holding surface, and if the imaging unit is out of focus, it is determined that no device is formed on the workpiece, and if the imaging unit is in focus, it is determined that a device is formed on the workpiece.

6. 6. The method for determining a workpiece according to claim 4 or 5, further comprising a processing step of, after the determination step, processing the workpiece if it is determined in the determination step that no device is formed on the workpiece, and issuing an error if it is determined in the determination step that a device is formed on the workpiece.

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