processing device

Abstract

This invention provides a processing apparatus on which an operator can verify the machining accuracy of a cutting groove. The processing apparatus includes: a chuck table having a plate-shaped holding member having a defined area formed of a transparent material from one side to the other; a first imaging unit for imaging the back side of the workpiece; a second imaging unit for imaging the front side of the workpiece; a display device; and a control unit that arranges at least any image information from a first image group showing the shape of the cutting groove and a second image group showing the shape of the cutting groove along the thickness direction of the workpiece, generates a three-dimensional image of the cutting groove, and displays it on the display device. The first and second image groups are obtained by sequentially positioning the focal points of the first and second imaging units at different positions along the thickness direction of the workpiece to image the cutting groove.

Description

Technical Field

[0001] The present invention relates to a processing apparatus for processing the back side of a workpiece while holding the front side of the workpiece on which a device is formed. Background Technology

[0002] Semiconductor device chips used in electronic devices such as mobile phones and personal computers are manufactured, for example, by processing a disk-shaped wafer (workpiece) made of semiconductor materials such as silicon. Multiple predetermined dividing lines are set on the front side of the workpiece, and devices such as ICs (Integrated Circuits), LSIs (Large Scale Integrations), and MEMSs (Micro-Electro-Mechanical Systems) are formed in the regions divided by these lines.

[0003] In order to manufacture device chips from workpieces, for example, after thinning the workpiece to a specified thickness by grinding the back side of the workpiece, the workpiece is cut along predetermined dividing lines to divide the workpiece into device units to manufacture device chips.

[0004] A cutting device is used in a cutting process to cut a workpiece. This cutting device has a cutting unit with a cutting tool mounted at one end of a spindle and a chuck table that holds the workpiece by attracting it. In a typical cutting process, the workpiece is first positioned with its front side facing up, and the back side of the workpiece is held by attracting it using the chuck table.

[0005] After maintaining the back side, the front side of the workpiece is photographed using a first camera positioned above the chuck stage to achieve alignment. The first camera has imaging elements such as a CCD (Charge-Coupled Device) image sensor and a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor for photographing the subject using visible light.

[0006] Alignment, including position correction, is performed based on the results of photographing the front side of the workpiece, which has alignment marks, etc., using a first camera. After alignment, the workpiece is cut along each predetermined dividing line using a cutting tool.

[0007] However, in recent years, with the diversification of devices, the workpiece is sometimes cut from the back side (for example, see Patent Document 1). In this case, since the front side of the workpiece is arranged facing down and held by the chuck stage, even if the back side of the workpiece is photographed using a first camera provided above the chuck stage, it is impossible to photograph alignment marks, etc.

[0008] Therefore, a cutting device has been developed that includes a chuck table made of a material transparent to visible light and a second camera for visible light disposed below the chuck table (see, for example, Patent Document 2). If a chuck table transparent to visible light is used, the front side of the workpiece can be photographed from below the chuck table while the workpiece is held in place by the chuck table.

[0009] However, in recent years, there has been a growing use of cutting tools to cut relatively hard semiconductor substrates (e.g., silicon carbide (SiC) substrates) used in semiconductor chips for power devices. In this case, the cutting groove is formed at an angle relative to the thickness direction of the substrate, or it is formed in a tapering manner at the tip, which may reduce the machining accuracy.

[0010] Patent Document 1: Japanese Patent Application Publication No. 2006-140341

[0011] Patent Document 2: Japanese Patent Application Publication No. 2010-87141

[0012] Therefore, in order to confirm the machining accuracy, it is desirable to confirm how the cutting groove is formed. However, in the existing cutting device described above, it is only possible to confirm the front and back images of the workpiece separately.

[0013] Therefore, currently, after the cutting groove is formed, the operator visually inspects the machined groove using a microscope or similar device. However, this visual inspection requires additional time after the cutting groove is formed, thus reducing work efficiency. Summary of the Invention

[0014] The present invention was made in view of the above-mentioned problems, and its object is to provide a machining apparatus in which the operator can confirm the machining accuracy of the cutting groove on the machining device.

[0015] According to one aspect of the present invention, a processing apparatus is provided for processing a plate-shaped workpiece held in a state of having its front side held, the workpiece having devices disposed in multiple regions divided by multiple predetermined dividing lines set on the front side, wherein the processing apparatus comprises: a chuck table having a plate-shaped holding member, the holding member including one surface and another surface located on the opposite side of the one surface, and having a defined area formed of a transparent material from the one surface to the other surface, the chuck table holding the front side of the workpiece; a processing unit for processing the workpiece held in the front side by the chuck table, forming a processing groove on the workpiece; a first imaging unit having a first imaging element disposed above the chuck table for imaging the back side of the workpiece held by the chuck table; and a second imaging unit having a second imaging element disposed below the chuck table for imaging the area captured by the first imaging unit. In the corresponding region along the thickness direction of the workpiece, the front side of the workpiece is photographed through the holding member; a display device displays an image of the workpiece acquired by at least any one of the first and second photographing units; and a control unit having a storage device storing a program for performing image processing and a processing device for processing the image according to the program. The control unit arranges at least any one of the first image information showing the shape of the processing groove in the first image group and the second image information showing the shape of the processing groove in the second image group along the thickness direction of the workpiece, thereby generating a three-dimensional image of the processing groove and displaying it on the display device. The first image group is obtained by photographing the processing groove by sequentially positioning the focal position of the first photographing unit at different positions along the thickness direction of the workpiece, and the second image group is obtained by photographing the processing groove by sequentially positioning the focal position of the second photographing unit at different positions along the thickness direction of the workpiece.

[0016] Preferably, the control unit generates a three-dimensional image of the processing groove by arranging the first image information and the second image information along the thickness direction of the workpiece.

[0017] In one aspect of the present invention, the control unit generates a three-dimensional image of a processing groove and displays it on a display device by arranging at least any image information from a first image information showing the shape of the processing groove in a first image group and a second image information showing the shape of the processing groove in a second image group along the thickness direction of the workpiece. The first image group is obtained by capturing the processing groove by sequentially positioning the focal position of a first imaging unit at multiple different positions along the thickness direction of the workpiece, and the second image group is obtained by sequentially positioning the focal position of a second imaging unit at multiple different positions along the thickness direction of the workpiece.

[0018] Therefore, the operator can confirm the machining accuracy of the groove by using a 3D image on the display device to confirm its shape. This eliminates the need for visual inspection of the workpiece using a microscope after transferring it from the machining unit to the microscope. Furthermore, since machining accuracy can be confirmed on the machining unit itself, work efficiency is improved compared to visual inspection. Attached Figure Description

[0019] Figure 1 It is a three-dimensional diagram of the cutting device.

[0020] Figure 2 It is a three-dimensional view of the workpiece unit.

[0021] Figure 3 It is a 3D view of the chuck, worktable, etc.

[0022] Figure 4 It is a partial cross-sectional side view of the chuck, worktable, etc.

[0023] Figure 5 yes Figure 4 A magnified view of region A.

[0024] Figure 6 It is an enlarged 3D view of the Z-axis moving mechanism, etc.

[0025] Figure 7 This is a diagram showing the cutting process.

[0026] Figure 8 This is a picture showing the situation of photographing the cutting groove with a tapered shape at the front end.

[0027] Figure 9 This is a diagram showing the incision inspection process.

[0028] Figure 10 This diagram illustrates the process of inspecting cuts using an interference optics system.

[0029] Figure 11Figure (A) is an example of a three-dimensional image showing the shape of a cutting groove represented by a set of points. Figure 11 Figure (B) is an example of a three-dimensional image of the cutting groove after interpolation.

[0030] Figure 12 It is a diagram showing the cross-sectional profile of the cutting groove.

[0031] Figure 13 It is a schematic diagram of a three-dimensional image of a cutting groove that is inclined relative to the thickness direction of the workpiece.

[0032] Figure 14 This is a 3D view of a laser processing device.

[0033] Label Explanation

[0034] 2: Cutting device; 4: Base; 4a, 4b, 4d: Openings; 4c: Support structure; 6: Box; 10: Chuck table; 11: Workpiece; 11a: Front side; 11b: Back side; 11c: Cutting groove; 12: Holding component; 12a: One face; 12b: Another face; 12c1: First suction path; 12c2: Second suction path; 12c3: Point; 12d: Opening; 12e: Outer peripheral suction path; 12f: Suction path; 13: Predetermined dividing line; 14: Suction source; 15: Device; 16: Frame; 16a: Opening; 16b: Pulley section; 17: Belt; 18: X-axis moving table; 18a: Base plate; 18b: Side Plate; 18c: Top plate; 18d: Space; 19: Frame; 20: X-axis guide rail; 20a: X-axis linear scale; 21: Workpiece unit; 22: X-axis ball screw; 23: First image group; 23a: First image information; 24: X-axis pulse motor; 25: Second image group; 25a: Second image information; 26: X-axis moving mechanism; 28: Belt; 30: Rotary drive source; 30a: Pulley; 32: Y-axis moving mechanism; 33: First image group; 33a: First point group (first image information); 34: Y-axis guide rail; 35: Second image group; 35a: Second point group (second image information); 36: Y-axis moving table; 38: Y-axis ball screw; 40: Y-axis pulse motor; 42: Z-axis moving mechanism; 42a: support structure; 44: Z-axis guide rail; 46: Z-axis moving plate; 48: Z-axis ball screw; 50: Z-axis pulse motor; 52: support arm; 54: lower imaging unit; 56: low-magnification camera; 56a: lighting device; 58: high-magnification camera; 58a: lighting device; 60: machining unit moving mechanism; 62: Y-axis guide rail; 64: Y-axis moving plate; 66: Y-axis ball screw; 68: Y-axis pulse motor; 70: Z-axis moving plate; 72: Z-axis guide rail; 74: Z-axis ball screw; 76: Z-axis pulse motor; 78: cutting unit; 8 0: Spindle housing; 82a: Spindle; 82b: Cutting tool; 84: Above imaging unit; 86: Cleaning unit; 88: Cleaning worktable; 90: Nozzle; 92: Touch panel; 94: Control unit; 96: Storage device; 102: Laser processing device; 104: Stationary base; 106: Y-axis moving worktable; 108: Y-axis guide rail; 108a: Y-axis scale; 110: Y-axis ball screw; 112: Y-axis pulse motor; 114: Y-axis moving mechanism; 116: Column; 118: Housing; 120: Laser irradiation unit; 120a: Laser oscillator; 122: Irradiation head; 122a: Condensing lens; A: Area; L: Laser beam. Detailed Implementation

[0035] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1This is a perspective view of the cutting device (machining device) 2 according to the first embodiment. Additionally, in Figure 1 In the diagram, a portion of the structural elements is shown using a function block diagram. Furthermore, the X-axis (machining feed direction), Y-axis (indexing feed direction), and Z-axis (vertical direction, infeed feed direction) used in the following description are perpendicular to each other.

[0036] The cutting device 2 has a base 4 that supports various structural elements. An opening 4a is formed at the front corner (+Y direction) of the base 4, and a box lift (not shown) is installed within this opening 4a. Multiple workpieces 11 (see reference) are placed on the upper surface of the box lift. Figure 2 Box 6.

[0037] The workpiece 11 is, for example, a disk-shaped (plate-shaped) wafer formed from a semiconductor material such as silicon. However, there are no limitations on the material, shape, structure, size, etc. of the workpiece 11. For example, a substrate formed from other semiconductor, ceramic, resin, metal, or other materials may also be used as the workpiece 11.

[0038] like Figure 2 As shown, multiple pre-defined dividing lines (spacers) 13 are intersecting on the front surface 11a of the workpiece 11. Devices such as ICs (Integrated Circuits) 15 and alignment marks (not shown) are formed in the multiple regions divided by the pre-defined dividing lines 13. However, there are no restrictions on the type, number, shape, structure, size, or arrangement of the devices 15.

[0039] A strip (scribing strip) 17 with a diameter larger than that of the workpiece 11 is adhered to the front side 11a of the workpiece 11. The strip 17 is formed of a transparent material that allows visible light to pass through. The strip 17 has, for example, a laminated structure having a substrate layer and an adhesive layer (paste layer).

[0040] The substrate layer is formed, for example, of polyolefin (PO). The adhesive layer is formed, for example, of an adhesive resin such as an ultraviolet (UV) curable acrylic resin. The adhesive layer side of the strip 17 is adhered to the front side 11a of the workpiece 11.

[0041] A ring-shaped frame 19 made of metal is fixed to the outer periphery of the belt 17. In this way, the workpiece 11 is stored in the box 6 as a workpiece unit 21 supported by the frame 19 via the belt 17. Figure 2 This is a three-dimensional view of the workpiece unit 21.

[0042] like Figure 1As shown, an opening 4b, which is elongated in the X-axis direction, is formed behind the opening 4a (in the -Y direction). A disc-shaped chuck stage 10 is disposed in the opening 4b. In addition, an annular frame suction plate (not shown) is provided on the outer periphery of the chuck stage 10, and suction ports are discretely formed along the circumferential direction on the frame suction plate.

[0043] Here, refer to Figures 3 to 5 A more detailed description is provided for the chuck worktable 10, etc. Figure 3 It is a 3D view of the chuck worktable 10, etc. Figure 4 This is a partial sectional side view of the chuck table 10, etc. However, in Figure 4 For convenience, the shading lines have been omitted. Figure 5 yes Figure 4 A magnified view of region A. Figure 5 In the diagram, a portion of the structural elements is shown using a functional block diagram.

[0044] The chuck table 10 has a disc-shaped (plate-shaped) retaining member 12. The retaining member 12 includes a generally flat surface 12a and another surface 12b located on the opposite side of the surface 12a (see reference). Figure 5 The retaining component 12 is made of a transparent material that allows visible light to pass through, such as soda glass, borosilicate glass, or quartz glass.

[0045] Multiple flow paths are formed inside the retaining member 12. In this embodiment, when viewed from above, a first linear attraction path 12c1 is formed inside the retaining member 12, traversing the central axis of the disk. Additionally, a second linear attraction path 12c2 is formed in the XY plane direction, perpendicular to the first attraction path 12c1.

[0046] The first attraction path 12c1 and the second attraction path 12c2 intersect at point 12c3 located on the central axis of the disk and are connected to each other. Multiple openings 12d are formed on the outer periphery of a surface 12a in a manner that separates them in the circumferential direction. Each opening 12d extends from one surface 12a to a predetermined depth without reaching another surface 12b.

[0047] An opening 12d is formed at both ends of the first attraction path 12c1 and the second attraction path 12c2. Each opening 12d is connected in the circumferential direction by an outer peripheral attraction path 12e formed at a predetermined depth on the outer periphery of the retaining member 12.

[0048] An attraction path 12f extending radially is formed on the outer periphery of the opening 12d, and an attraction source 14, such as an injector, is connected to the attraction path 12f (see reference). Figure 5When the suction source 14 is activated to generate negative pressure, negative pressure is generated at the opening 12d. Therefore, one surface 12a functions as a holding surface that attracts and holds the workpiece unit 21 (workpiece 11).

[0049] Furthermore, in the flow paths of the holding member 12, such as the first attraction path 12c1, the second attraction path 12c2, the opening 12d, the outer peripheral attraction path 12e, and the attraction path 12f, a portion of the incident light is scattered or reflected. Therefore, when viewed from one surface 12a or the other surface 12b, there are cases where the flow paths of the holding member 12 are translucent to visible light but not completely transparent, or opaque.

[0050] However, the designated area of ​​the retaining component 12, excluding the flow path, is transparent from one surface 12a to another surface 12b. For example, the area divided into four parts by the first attraction path 12c1 and the second attraction path 12c2 and located radially inside the retaining component 12 compared to the outer peripheral attraction path 12e is transparent from one surface 12a to another surface 12b.

[0051] A cylindrical frame 16 made of a metal material such as stainless steel is provided on the outer periphery of the retaining component 12. An opening 16a is formed in the upper part of the frame 16 (see reference). Figure 5 The retaining component 12 is configured to close the opening 16a.

[0052] like Figure 3 and Figure 4 As shown, the frame 16 is supported by an X-axis movable stage 18. The X-axis movable stage 18 includes a rectangular base plate 18a when viewed from the Z-axis direction. One front end (+Y direction) of the base plate 18a is connected to the lower end of a rectangular side plate 18b when viewed from the Y-axis direction.

[0053] The upper end of the side plate 18b is connected to the front end of the top plate 18c, which has the same rectangular shape as the bottom plate 18a when viewed from the Z-axis direction. A space 18d is formed between the bottom plate 18a and the top plate 18c, open at one end in the rear (-Y direction) and at both ends in the X-axis direction.

[0054] Below the base plate 18a (in the -Z direction), a pair of X-axis guide rails 20, approximately parallel to the X-axis direction, are provided so that the base plate 18a can slide. The pair of X-axis guide rails 20 are fixed to the upper surface of the stationary base (not shown).

[0055] An X-axis linear scale 20a is provided adjacent to the X-axis guide rail 20 for detecting the position of the X-axis moving stage 18 in the X-axis direction. Additionally, a reading head (not shown) is provided on the lower surface of the X-axis moving stage 18.

[0056] When the X-axis moving stage 18 moves, the position (coordinates) of the X-axis moving stage 18 and the amount of movement in the X-axis direction are calculated by using the reading head to detect the scale of the X-axis linear scale 20a.

[0057] A nut portion (not shown) is provided on the lower surface of the base plate 18a of the X-axis moving worktable 18, and an X-axis ball screw 22 that is approximately parallel to the X-axis guide rail 20 is rotatably connected to the nut portion.

[0058] An X-axis pulse motor 24 is connected to one end of the X-axis ball screw 22. If the X-axis ball screw 22 is rotated by the X-axis pulse motor 24, the X-axis moving table 18 moves along the X-axis guide rail 20 in the X-axis direction. The X-axis guide rail 20, X-axis ball screw 22, X-axis pulse motor 24, etc. constitute the X-axis moving mechanism 26 that moves the X-axis moving table 18.

[0059] On the upper surface of the top plate 18c of the X-axis moving stage 18, the frame 16 is supported on the top plate 18c in a manner that allows it to rotate about a rotation axis that is approximately parallel to the Z-axis direction. The frame 16 includes a cylindrical side, namely a pulley portion 16b. When the frame 16 is supported by the X-axis moving stage 18, the pulley portion 16b is located above the top plate 18c.

[0060] A rotary drive source 30, such as an electric motor, is installed on the side plate 18b of the X-axis moving worktable 18. A pulley 30a is installed on the rotating shaft of the rotary drive source 30. A rotating annular belt (belt 28) is suspended on the pulley 30a and the pulley section 16b.

[0061] When the rotary drive source 30 is activated to rotate the pulley 30a, the frame 16 rotates about a rotation axis that is approximately parallel to the Z-axis direction through the force transmitted via the belt 28. By controlling the rotation of the pulley 30a, the chuck table 10 can be rotated at any angle about the rotation axis.

[0062] A Y-axis moving mechanism 32 is provided on the extension line of the X-axis moving mechanism 26 in the X-axis direction. The Y-axis moving mechanism 32 has a pair of Y-axis guide rails 34 that are approximately parallel to the Y-axis direction. The pair of Y-axis guide rails 34 are fixed to the upper surface of the stationary base (not shown).

[0063] A Y-axis movable worktable 36 is slidably mounted on the Y-axis guide rail 34. A nut portion (not shown) is provided on the lower surface of the Y-axis movable worktable 36, and a Y-axis ball screw 38 that is substantially parallel to the Y-axis guide rail 34 is rotatably connected to the nut portion.

[0064] A Y-axis pulse motor 40 is connected to one end of the Y-axis ball screw 38. If the Y-axis ball screw 38 is rotated by the Y-axis pulse motor 40, the Y-axis moving table 36 moves along the Y-axis guide rail 34 in the Y-axis direction.

[0065] A Y-axis linear scale (not shown) is provided adjacent to the Y-axis guide rail 34 for detecting the position of the Y-axis moving stage 36 in the Y-axis direction. Additionally, a reading head (not shown) is provided on the lower surface of the Y-axis moving stage 36.

[0066] When the Y-axis moving table 36 moves, the position (coordinates) of the Y-axis moving table 36 and the amount of movement in the Y-axis direction are calculated by using the reading head to detect the scale of the Y-axis linear scale.

[0067] A Z-axis moving mechanism 42 is provided on the upper surface of the Y-axis moving worktable 36. Figure 6 This is an enlarged perspective view of the Z-axis moving mechanism 42, etc. The Z-axis moving mechanism 42 has a support structure 42a fixed to the upper surface of the Y-axis moving worktable 36.

[0068] A pair of Z-axis guide rails 44, approximately parallel to the Z-axis direction, are fixed on the side of the X-axis movable worktable 18 of the support structure 42a. A Z-axis movable plate 46 is slidably mounted on the Z-axis guide rails 44.

[0069] A nut portion (not shown) is provided on the back side of the Z-axis moving plate 46 (Z-axis guide rail 44 side), and a Z-axis ball screw 48 that is approximately parallel to the Z-axis guide rail 44 is rotatably connected to the nut portion.

[0070] A Z-axis pulse motor 50 is connected to one end of the Z-axis ball screw 48. If the Z-axis ball screw 48 is rotated by the Z-axis pulse motor 50, the Z-axis moving plate 46 moves along the Z-axis guide rail 44 in the Z-axis direction.

[0071] A Z-axis linear scale (not shown) is provided adjacent to the Z-axis guide rail 44, and a reading head (not shown) is provided on the side of the Z-axis guide rail 44 of the Z-axis moving plate 46. When the Z-axis moving plate 46 moves, the reading head is used to detect the scale of the Z-axis linear scale to calculate the position (coordinates) of the Z-axis moving plate 46 in the Z-axis direction.

[0072] A lower imaging unit (second imaging unit) 54 is fixed on the Z-axis moving plate 46 by means of a support arm 52 that is long in the X-axis direction. The lower imaging unit 54 in this embodiment includes a low-magnification camera 56 and a high-magnification camera 58.

[0073] The low-magnification camera 56 and the high-magnification camera 58 each have a specified optical system such as a condenser lens and an imaging element such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor (second imaging element).

[0074] The lower imaging unit 54 is positioned below the chuck table 10 and is positioned opposite the other surface 12b in such a way that the optical axes of each condenser lens are substantially perpendicular to the other surface 12b of the holding member 12.

[0075] An illumination device 56a is provided on the side of the low-magnification camera 56 to illuminate a subject (e.g., workpiece 11) located above it with visible light. Similarly, an illumination device 58a is also provided on the side of the high-magnification camera 58.

[0076] When the workpiece 11 is photographed using the lower imaging unit 54, the X-axis moving stage 18 is moved towards the Y-axis moving stage 36, and the lower imaging unit 54 is positioned in the space 18d. Then, the workpiece 11, which is positioned on one side 12a of the holding member 12, is photographed from below using the holding member 12.

[0077] In this way, an upright image (i.e., the image actually observed) can be obtained from the front 11a side. Furthermore, the lower imaging unit 54 may not necessarily have both a low-magnification camera 56 and a high-magnification camera 58. The lower imaging unit 54 may also have only one camera with a specified magnification.

[0078] Here, return Figure 1 The other structural elements of the cutting device 2 will be described below. A retractable corrugated dustproof and dripproof cover is installed at a position in the +X and -X directions relative to the top plate 18c of the X-axis moving worktable 18, in a manner that covers the opening 4b.

[0079] A gate-shaped support structure 4c is provided above the opening 4b and spans the opening 4b. Two machining unit moving mechanisms (indexing feed unit and infeed feed unit) 60 are provided on one side of the support structure 4c located on the side of the opening 4a.

[0080] Each processing unit's moving mechanism 60 shares a pair of Y-axis guide rails 62 fixed to one side of the support structure 4c and approximately parallel to the Y-axis direction. Two Y-axis moving plates 64 are mounted on the Y-axis guide rails 62 in a manner that allows them to slide independently of each other.

[0081] A nut portion (not shown) is provided on one side of the Y-axis moving plate 64 located on the support structure 4c side. A Y-axis ball screw 66, which is approximately parallel to the Y-axis guide rail 62, is rotatably connected to this nut portion. In addition, the nut portion of each Y-axis moving plate 64 is connected to a different Y-axis ball screw 66.

[0082] A Y-axis pulse motor 68 is connected to one end of each Y-axis ball screw 66. If the Y-axis ball screw 66 is rotated by the Y-axis pulse motor 68, the Y-axis moving plate 64 moves along the Y-axis guide rail 62 in the Y-axis direction.

[0083] On the opposite side of each Y-axis movable plate 64, located on the other side of the support structure 4c, a pair of Z-axis guide rails 72, approximately parallel to the Z-axis direction, are respectively provided. Z-axis movable plates 70 are slidably mounted on the Z-axis guide rails 72.

[0084] A nut portion (not shown) is provided on one side of the Z-axis moving plate 70 located on the support structure 4c side, and a Z-axis ball screw 74 parallel to the Z-axis guide rail 72 is rotatably connected to the nut portion.

[0085] A Z-axis pulse motor 76 is connected to one end of the Z-axis ball screw 74. If the Z-axis ball screw 74 is rotated by the Z-axis pulse motor 76, the Z-axis moving plate 70 moves along the Z-axis guide rail 72 in the Z-axis direction.

[0086] A cutting unit (machining unit) 78 is provided at the lower part of the Z-axis moving plate 70. The cutting unit 78 has a cylindrical spindle housing 80. A generally cylindrical spindle 82a (see reference) is rotatably housed inside the spindle housing 80. Figure 7 Part of ).

[0087] A rotary drive mechanism (not shown) such as an electric motor is provided at one end of the spindle 82a to rotate the spindle 82a. In addition, a cutting tool 82b with a ring-shaped cutting edge is installed at the other end of the spindle 82a.

[0088] When cutting (machining) the workpiece 11 using the cutting tool 82b, firstly, after attracting and holding the front face 11a of the workpiece 11 using the chuck table 10, the predetermined dividing line 13 is positioned approximately parallel to the X-axis direction.

[0089] Then, with the lower end of the rotating cutting tool 82b positioned between the front face 11a and one face 12a of the holding member 12, the chuck table 10 is moved along the X-axis. Thus, as... Figure 7 As shown, a cutting groove (machining groove) 11c is formed by cutting the workpiece 11. Figure 7This is a diagram showing the formation of a cutting groove 11c on the workpiece 11.

[0090] In this embodiment, the cutting groove 11c is a so-called full-cut groove that extends from the back side 11b to the front side 11a. The cutting groove 11c is sometimes formed obliquely relative to the thickness direction of the workpiece 11, or it is formed such that the front end tapers as it moves from the back side 11b toward the front side 11a.

[0091] Therefore, it is desirable to confirm the formation of the cutting groove 11c in the workpiece 11 on the cutting device 2. In this embodiment, the shape of the cutting groove 11c is confirmed using the lower imaging unit 54 and the upper imaging unit (first imaging unit) 84 described above.

[0092] The upper imaging unit 84 is connected to the lower part of the Z-axis moving plate 70 adjacent to the cutting unit 78. The upper imaging unit 84 has a prescribed optical system such as a condenser lens and an imaging element (first imaging element).

[0093] The upper imaging unit 84 is positioned above the chuck table 10 and is arranged opposite to one surface 12a of the holding member 12, with the optical axis of the condenser lens approximately perpendicular to the surface 12a. The upper imaging unit 84 captures an image of the back side 11b of the workpiece 11 held by the surface 12a on the front side 11a. This allows for the acquisition of a frontal image of the back side 11b.

[0094] An opening 4d is provided on the opposite side of opening 4a, relative to opening 4b. A cleaning unit 86 for cleaning the workpiece 11 after cutting is provided in opening 4d. The cleaning unit 86 includes a cleaning table 88 for attracting and holding the workpiece 11 and a nozzle 90 with a spray port arranged opposite to the cleaning table 88.

[0095] A housing (not shown) is mounted on the base 4, and a touch panel (display device) 92, which serves as both an input and display unit, is mounted on the front side of the housing. The touch panel 92 displays images captured by at least one of the lower imaging unit 54 and the upper imaging unit 84, processing conditions, GUI (Graphical User Interface), etc.

[0096] Alternatively, the input section and the display section can be separated. In this case, instead of the touch panel 92, a display device such as a video monitor or computer screen and an input device such as a keyboard or mouse serving as a user interface can be provided on the front side of the housing.

[0097] The cutting device 2 has a control unit 94, which controls the suction source 14, the X-axis moving mechanism 26, the rotary drive source 30, the Y-axis moving mechanism 32, the Z-axis moving mechanism 42, the lower imaging unit 54, the processing unit moving mechanism 60, the upper imaging unit 84, the cutting unit 78, the touch panel 92, etc.

[0098] The control unit 94 may be composed of, for example, a computer, which includes: a processing device such as a processor (CPU); a main storage device such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), and ROM (Read Only Memory); and auxiliary storage devices such as flash memory, hard disk drives, and solid-state drives.

[0099] The auxiliary storage device stores software containing a prescribed program. This software causes the processing device to operate, thereby realizing the function of the control unit 94. Furthermore, a portion of the auxiliary storage device functions as a storage device 96, which stores a program that causes the processing device to perform prescribed image processing (generation of a 3D image).

[0100] Here, the image acquisition and image processing in this embodiment will be described. In this embodiment, firstly, the focal positions of the upper imaging unit 84 and the lower imaging unit 54 are sequentially positioned at multiple different locations along the thickness direction of the workpiece 11 to capture images of the cutting groove 11c.

[0101] The workpiece 11 is arranged such that the thickness direction of the workpiece 11 from the front side 11a to the back side 11b is approximately parallel to the Z-axis direction. Figure 8 This diagram illustrates the use of the upper imaging unit 84 and the lower imaging unit 54 to capture images of the front-end tapering cutting groove 11c.

[0102] In this embodiment, after the upper imaging unit 84, which is focused on the back surface 11b, captures an image of the cutting groove 11c, the processing unit moving mechanism 60 moves the upper imaging unit 84 downward at 1μm intervals to capture images of the cutting groove 11c at various positions. This yields the first image group 23.

[0103] Furthermore, after capturing images of the cutting groove 11c using the lower imaging unit 54 focused on the front 11a, the Z-axis movement mechanism 42 moves the lower imaging unit 54 upward at 1μm intervals to capture images of the cutting groove 11c at various positions. Thus, the second image group 25 is obtained.

[0104] At this time, the XY coordinates of each condenser lens are adjusted by the X-axis moving mechanism 26, the Y-axis moving mechanism 32, and the processing unit moving mechanism 60, so that the lower shooting unit 54 and the upper shooting unit 84 can shoot the corresponding area in the thickness direction of the workpiece 11.

[0105] Furthermore, there is no particular limitation on the order in which the first image group 23 and the second image group 25 are acquired. Alternatively, the upper imaging unit 84 can be moved upwards at a predetermined interval, and the lower imaging unit 54 can be moved downwards at a predetermined interval.

[0106] Each of the plurality of images constituting the first image group 23 includes first image information 23a, which shows the edge of the cutting groove 11c at a depth corresponding to the focal position (i.e., shows the shape of the cutting groove 11c). Similarly, each of the plurality of images constituting the second image group 25 includes second image information 25a showing the shape of the cutting groove 11c.

[0107] After the image is acquired, image processing is performed. In image processing, the first image information 23a and the second image information 25a are arranged in order of height along the thickness direction of the workpiece 11 according to the focal position. However, the first image information 23a and the second image information 25a are discrete in the thickness direction of the workpiece 11.

[0108] Therefore, known methods such as nearest neighbor interpolation and bilinear interpolation are used to interpolate adjacent image information. This generates a three-dimensional image of the cutting groove 11c. This three-dimensional image is displayed on the touch panel 92 (see reference). Figure 9 ).

[0109] The operator can confirm the shape of the cutting groove 11c using a 3D image, thereby confirming the machining accuracy of the cutting groove 11c. Therefore, it is not necessary to transfer the workpiece 11 from the cutting device 2 to the microscope for visual inspection using a microscope. In addition, since the machining accuracy can be confirmed on the cutting device 2, the work efficiency can be improved compared to visual inspection.

[0110] Next, the processing method of the workpiece 11 will be described. First, the workpiece unit 21 is placed on one surface 12a of the chuck table 10 with its back side 11b exposed to the side and upward (loading process S10).

[0111] After the loading step S10, the suction source 14 is activated to hold the front 11a side of the workpiece 11 across the belt 17 using a surface 12a, and the frame 19 is held using a frame suction plate (not shown) (holding step S20). After the holding step S20, the teaching step S30 is performed.

[0112] In the teaching process S30, for example, while the front 11a side is photographed using the lower shooting unit 54 and the resulting image is displayed in real time on the touch panel 92 after being converted into a mirror image, the operator looks for the alignment mark (not shown) on the front 11a side.

[0113] After the desired alignment mark is found, an image of the front side 11a, including the alignment mark, is acquired using the lower imaging unit 54. The shape, coordinates, etc., of the alignment mark are stored as a template for pattern matching in, for example, a storage device 96.

[0114] Furthermore, the distance between the alignment mark and the center line of the pre-division line 13, as well as the distance between two adjacent pre-division lines 13 in the Y-axis direction (interval spacing) are stored in the storage device 96. Additionally, the stored coordinates are XY coordinates with the aforementioned point 12c3 as the origin.

[0115] After the teaching process S30, the workpiece 11 is aligned (alignment process S40). In the alignment process S40, the operator performs the operation while the image obtained by converting the frontal image 11a side captured by the lower imaging unit 54 into a mirror image is displayed on the touch panel 92 in real time.

[0116] In the alignment process S40, firstly, an image of the front side 11a is obtained using the lower imaging unit 54 (e.g., a low-magnification camera 56) at multiple mutually separated locations on a predetermined dividing line 13 along the X-axis direction.

[0117] Then, in the images of the front 11a side obtained at multiple locations, a pattern identical to the alignment mark stored as a template is detected through a prescribed process such as pattern matching. Based on the pattern identical to the detected alignment mark, the offset of the dividing predetermined line 13 in the θ direction about the central axis of the holding member 12 is determined.

[0118] Then, the rotation drive source 30 is activated to rotate the belt 28 by a predetermined amount, thereby correcting the offset in the θ direction of the predetermined dividing line 13. This positions the predetermined dividing line 13 approximately parallel to the X-axis direction.

[0119] After alignment step S40, while the workpiece 11 is held in the position of front side 11a by the chuck table 10, cutting (machining) is performed on the workpiece 11 (cutting step S50) (see reference). Figure 7 In the cutting process S50, firstly, the high-speed rotating cutting tool 82b is positioned on the extension line of the predetermined dividing line 13.

[0120] At this time, the lower end of the cutting tool 82b is positioned between the front face 11a and one face 12a of the holding member 12. Then, the chuck table 10 and the cutting tool 82b are moved relative to each other along the X-axis direction by the X-axis moving mechanism 26. As a result, a cutting groove 11c that completely cuts the workpiece 11 is formed in the thickness direction of the workpiece 11.

[0121] After cutting the workpiece 11 along a predetermined dividing line 13 parallel to the X-axis, the cutting tool 82b is positioned on the extension of the adjacent predetermined dividing line 13 along the Y-axis by indexing the cutting unit 78. Then, the workpiece 11 is cut along the predetermined dividing line 13 in the same manner.

[0122] After cutting the workpiece 11 along all the predetermined dividing lines 13 parallel to the first direction, the rotary drive source 30 is activated to rotate the chuck table 10 by 90 degrees. Then, the second direction, which is perpendicular to the first direction, is positioned parallel to the X-axis direction, and the workpiece 11 is cut along all the predetermined dividing lines 13 parallel to the second direction.

[0123] After the cutting operation S50, the cut inspection operation S60 is performed. Figure 9 This diagram illustrates the cut inspection process S60. In the cut inspection process S60, the focal points of the upper imaging unit 84 and the lower imaging unit 54 are sequentially positioned at multiple different locations along the depth direction of the cutting groove 11c to capture images of the cutting groove 11c.

[0124] The operator uses the 3D image displayed on the touch panel 92 to confirm the shape of the cutting groove 11c, thereby confirming the machining accuracy of the cutting groove 11c. Therefore, it is not necessary to transfer the workpiece 11 from the cutting device 2 to the microscope for visual inspection using a microscope. In addition, since the machining accuracy can be confirmed on the cutting device 2, the work efficiency can be improved compared to visual inspection.

[0125] In addition, in this embodiment, the case where the cut inspection process S60 is performed after the cutting process S50 is completed is described. However, as long as one or more cutting grooves 11c are formed, the cut inspection process S60 can also be performed in the middle of the cutting process S50.

[0126] In the above embodiment, the case of photographing the cutting groove 11c by changing the focal positions of both the upper imaging unit 84 and the lower imaging unit 54 was described. By changing the focal positions of both units, even when the cutting groove 11c has a tapered front end or is formed at an angle relative to the thickness direction of the workpiece 11, the shape of the cutting groove 11c can be properly grasped by mutually filling the blind spots of the imaging field of view.

[0127] However, it is also possible to position the focus of the upper imaging unit 84 at multiple different locations along the depth direction of the cutting groove 11c to capture images of the cutting groove 11c. In this case, the first image group 23 is obtained by capturing images of the cutting groove 11c using the upper imaging unit 84.

[0128] Then, the first image information 23a from each image of the first image group 23 is arranged along the thickness direction of the workpiece 11. However, since the first image information 23a is discrete in the thickness direction of the workpiece 11, a three-dimensional image of the cutting groove 11c is generated by interpolating between adjacent image information.

[0129] In addition, the three-dimensional image may also include a frontal image obtained by focusing the lower shooting unit 54 on the front 11a to capture the front 11a, and auxiliary lines for interpolating between the three-dimensional image and the frontal image.

[0130] Similarly, the focus position of the lower imaging unit 54 can be sequentially positioned at multiple different locations along the depth direction of the cutting groove 11c to capture images of the cutting groove 11c. In this case, the second image group 25 is obtained by capturing images of the cutting groove 11c using the lower imaging unit 54.

[0131] Then, the second image information 25a from each image of the second image group 25 is arranged along the thickness direction of the workpiece 11. However, since the second image information 25a is discrete in the thickness direction of the workpiece 11, a three-dimensional image of the cutting groove 11c is generated by interpolating between adjacent image information.

[0132] Additionally, the three-dimensional image may also include a back image obtained by focusing the upper shooting unit 84 on the back 11b to capture the back 11b, and auxiliary lines for interpolating between the three-dimensional image and the back image.

[0133] In this way, by arranging at least one of the first image information 23a and the second image information 25a along the thickness direction of the workpiece 11, a three-dimensional image of the cutting groove 11c can be generated at least locally. Even in this case, by confirming the shape of the cutting groove 11c using the three-dimensional image, the machining accuracy of the cutting groove 11c can be confirmed to some extent.

[0134] Next, a variation of the first embodiment will be described. In this variation, the upper imaging unit 84 and the lower imaging unit 54 are imaging units equipped with interference optical systems. The interference optical system can be a Milau type, a Michelson type, a linear type, or the like.

[0135] Figure 10 This diagram illustrates the use of an interference optical system for the cut inspection process S60. When using the interference optical system, the focal points of the upper imaging unit 84 and the lower imaging unit 54 are sequentially positioned at multiple different locations along the thickness direction of the workpiece 11 to capture images of the cutting groove 11c.

[0136] For example, with the focus of the upper imaging unit 84 aligned with the back surface 11b, the chuck stage 10 is moved a predetermined length along the X-axis. Then, after moving the upper imaging unit 84 a predetermined length along the Y-axis, it is moved a predetermined length in the opposite direction along the X-axis.

[0137] Therefore, the focal point of the upper imaging unit 84 is scanned within the defined plane of the back surface 11b. Interference light with high intensity is generated at the focal point of the upper imaging unit 84.

[0138] After scanning the back surface 11b using the upper imaging unit 84, the upper imaging unit 84 is moved downward by 0.1 μm using the processing unit moving mechanism 60. Then, at this height position, the focal point of the upper imaging unit 84 is scanned again in the specified XY plane.

[0139] The upper imaging unit 84 is moved downwards at 0.1 μm intervals, and at each height position, the focus of the upper imaging unit 84 is scanned within a specified XY plane, thereby capturing images of the cutting groove 11c. This yields the first image group 33.

[0140] Each image constituting the first image group 33 includes a first point group (i.e., first image information) 33a, which shows points where interference light with high intensity is generated due to the focus being aligned with the edge of the cutting groove 11c. That is, the first point group 33a defines the inner wall of the cutting groove 11c, etc., and shows the shape of the cutting groove 11c.

[0141] Similarly, after scanning the front side 11a using the lower imaging unit 54, the lower imaging unit 54 is moved upward at 0.1 μm intervals, and at each height position, the focus of the lower imaging unit 54 is scanned within a specified XY plane, thereby capturing the cutting groove 11c. Thus, the second image group 35 is obtained.

[0142] Each image constituting the second image group 35 also includes a second point group (i.e., second image information) 35a showing the shape of the cutting groove 11c. By arranging both the first point group 33a and the second point group 35a along the thickness direction of the workpiece 11 through image processing, a three-dimensional image of the cutting groove 11c is generated.

[0143] The 3D image is displayed on touch panel 92. Figure 11 Figure (A) is an example of a three-dimensional image showing the shape of the cutting groove 11c represented by a group of points. Alternatively, a three-dimensional image of the cutting groove 11c can be generated by interpolating between adjacent points through image processing. Figure 11 Figure (B) is an example of a three-dimensional image of the cutting groove 11c after interpolation.

[0144] Operators use Figure 11 (A) or Figure 11 The three-dimensional image shown in (B) confirms the shape of the cutting groove 11c, thereby enabling the confirmation of the machining accuracy of the cutting groove 11c. Therefore, it is not necessary to transfer the workpiece 11 from the cutting device 2 to the microscope for visual inspection of the workpiece 11 using a microscope. In addition, since the machining accuracy can be confirmed on the cutting device 2, the work efficiency can be improved compared to the case of visual inspection.

[0145] Additionally, as described above, a three-dimensional image of the cutting groove 11c can be generated at least locally by arranging at least one of the first point group 33a and the second point group 35a along the thickness direction of the workpiece 11.

[0146] Figure 12 This is a diagram showing the cross-sectional profile of a cutting groove 11c arranged approximately parallel to the X-axis direction when cut by the YZ plane. The horizontal axis represents the width (μm) of the cutting groove 11c, and the vertical axis represents the depth (μm) of the cutting groove 11c.

[0147] In addition, Figures 8 to 12 In the description, the cutting groove 11c is explained as tapering towards the front end as it moves from the back side 11b toward the front side 11a. However, even when the cutting groove 11c is formed at an angle relative to the thickness direction of the workpiece 11, the machining accuracy of the cutting groove 11c can be confirmed on the cutting device 2.

[0148] Figure 13This is a schematic diagram of a three-dimensional image of a cutting groove 11c formed at an angle relative to the thickness direction of the workpiece 11. Additionally, Figure 13 The back side 11b and the front side 11a are images obtained by the upper shooting unit 84 and the lower shooting unit 54 of the first embodiment, but the back side 11b and the front side 11a are interpolated by auxiliary lines.

[0149] In addition, Figure 13 In the diagram, the dashed line represents the edge of the cutting groove 11c, and the solid line represents the center of the width of the cutting groove 11c. On the front side 11a, the cutting groove 11c is formed offset from the predetermined dividing line 13. Even when the cutting groove 11c is formed at an angle, the shape of the cutting groove 11c can be confirmed by generating a three-dimensional image according to the first embodiment or its variations.

[0150] Next, the second embodiment will be described. In the second embodiment, a laser processing apparatus (processing apparatus) 102 is used instead of a cutting apparatus 2 to process the workpiece 11. However, the above-described placement process S10 to alignment process S40 are performed in the same manner as in the first embodiment.

[0151] Figure 14 This is a perspective view of the laser processing apparatus 102 according to the second embodiment. Furthermore, structural elements identical to those in the cutting apparatus 2 of the first embodiment are labeled with the same reference numerals. Hereinafter, the differences from the cutting apparatus 2 will be mainly described.

[0152] In the laser processing apparatus 102, a lower imaging unit 54 is fixed on a stationary base 104. Alternatively, the lower imaging unit 54 can be configured to move along either the X-axis or the Y-axis.

[0153] An X-axis movable stage 18 is disposed on a stationary base 104. The X-axis movable stage 18 is configured such that the lower imaging unit 54 can enter the space 18d from the area of ​​the X-axis movable stage 18 located on the opposite side of the side plate 18b.

[0154] The X-axis movable stage 18 is slidably mounted on a pair of X-axis guide rails 20. The pair of X-axis guide rails 20 are fixed on the Y-axis movable stage 106.

[0155] A nut portion (not shown) is provided on the lower surface of the base plate 18a of the X-axis moving worktable 18, and an X-axis ball screw 22 that is approximately parallel to the X-axis guide rail 20 is rotatably connected to the nut portion.

[0156] An X-axis pulse motor 24 is connected to one end of the X-axis ball screw 22. If the X-axis ball screw 22 is rotated by the X-axis pulse motor 24, the X-axis moving table 18 moves along the X-axis guide rail 20 in the X-axis direction.

[0157] The Y-axis movable stage 106, which supports the X-axis movable stage 18, is slidably mounted on a pair of Y-axis guide rails 108 fixed to the upper surface of the stationary base 104. A Y-axis scale 108a, used for detecting the position of the Y-axis movable stage 106 in the Y-axis direction, is provided adjacent to the Y-axis guide rails 108.

[0158] A nut portion (not shown) is provided on the lower surface of the Y-axis moving worktable 106, and a Y-axis ball screw 110, which is approximately parallel to the Y-axis guide rail 108, is rotatably connected to the nut portion. A Y-axis pulse motor 112 is connected to one end of the Y-axis ball screw 110.

[0159] If the Y-axis ball screw 110 is rotated by the Y-axis pulse motor 112, the Y-axis moving table 106 moves along the Y-axis guide rail 108 in the Y-axis direction. The Y-axis guide rail 108, the Y-axis ball screw 110, the Y-axis pulse motor 112, etc. constitute the Y-axis moving mechanism 114 that moves the Y-axis moving table 106.

[0160] A column 116 is provided adjacent to the lower imaging unit 54, protruding upward from the upper surface of the stationary base 104. A housing 118 having an elongated portion approximately parallel to the X-axis direction is provided on the column 116.

[0161] At least a portion of a laser irradiation unit 120 is provided in the housing 118. The laser irradiation unit 120 includes a laser oscillator 120a, which generates a pulsed laser beam having a wavelength absorbed by the workpiece 11 or a wavelength transmitted through the workpiece 11.

[0162] An irradiation head 122, including a focusing lens 122a, is provided at the front end of the laser irradiation unit 120 in the X-axis direction. The laser beam emitted from the laser oscillator 120a is focused by the focusing lens 122a and irradiates downward from the irradiation head 122.

[0163] exist Figure 14 In the diagram, a dashed arrow indicates the laser beam L irradiating downwards from the irradiation head 122. Additionally, the aforementioned upward imaging unit 84 is provided at the front end of the housing 118, adjacent to the irradiation head 122.

[0164] In the cutting process S50 of the second embodiment, the focusing point of the laser beam L is positioned near the back surface 11b of the workpiece 11, and the focusing point and the workpiece 11 are moved relative to each other in the X-axis direction, thereby forming a section along the predetermined dividing line 13. Figure 8 A laser processing tank as shown (not illustrated).

[0165] Then, during the cut inspection process S60, as in the first embodiment or its variations, the control unit 94 generates a three-dimensional image of the cutting groove 11c. The operator uses the three-dimensional image displayed on the touch panel 92 to confirm the shape of the laser-processed groove, thereby confirming the processing accuracy of the laser-processed groove.

[0166] Therefore, it is not necessary to transfer the workpiece 11 from the cutting device 2 to the microscope for visual inspection using a microscope. In addition, since the machining accuracy can be confirmed on the laser processing device 102, the work efficiency can be improved compared to visual inspection.

[0167] In addition, the structure and method of the above embodiments can be implemented by appropriate modifications without departing from the purpose of the present invention.

Claims

1. A processing apparatus for processing a plate-shaped workpiece while holding its front side, the workpiece having devices disposed in multiple regions divided by multiple predetermined dividing lines set on the front side, characterized in that, The processing device has the following features: A chuck table having a plate-shaped holding member comprising a face and another face opposite to the face, and having a defined area formed of a transparent material from the face to the other face, the chuck table holding the front side of the workpiece. A processing unit that processes the workpiece held on the front by the chuck table, forming a processing groove on the workpiece; The first imaging unit has a first imaging element, which is disposed above the chuck table and performs imaging on the back side of the workpiece held by the chuck table. The second imaging unit has a second imaging element, which is disposed below the chuck worktable and captures the front side of the workpiece in an area corresponding to the area captured by the first imaging unit in the thickness direction of the workpiece, with the holding member in between. A display device that displays an image of the workpiece acquired by at least any one of the first and second imaging units; as well as The control unit has a storage device storing a program for performing image processing and a processing device for processing images according to the program. The control unit generates a three-dimensional image of the processing groove and displays it on the display device by arranging first image information showing the shape of the processing groove in a first image group and second image information showing the shape of the processing groove in a second image group along the thickness direction of the workpiece. The first image group is obtained by capturing the processing groove by sequentially positioning the focal position of the first imaging unit at multiple different positions along the thickness direction of the workpiece, and the second image group is obtained by sequentially positioning the focal position of the second imaging unit at multiple different positions along the thickness direction of the workpiece.

Images