Processing method of workpiece

Abstract

To provide a processing method for a work-piece, which when positions of center lines which have to be matched with each other on both surfaces of a work-piece deviate in a predetermined plane, corrects a processing position so that the positions match with each other and then proceeds with processing.SOLUTION: The processing method of a work-piece comprises: a first processing groove forming step of forming a first processed groove using a first processing unit; an imaging step of making a first imaging unit image the first processed groove and making a second imaging unit provided at the opposite side of the first imaging unit with respect to a holding table image a predetermined line at a position corresponding to the first processed groove in a thickness direction of the work-piece; a detecting step of detecting whether or not a position of a first center line of the first processed groove matches with a position of a second center line of the predetermined line in the predetermined plane; and a correcting step of correcting the processing position so that the position of the first center line matches with the position of the second center line, when the detecting step shows that the position of the first center line does not match with the position of the second center line.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a workpiece processing method for processing a workpiece held by a holding table having a region formed of a transparent material.

Background Art

[0002] Electronic devices such as mobile phones and personal computers are equipped with device chips. Device chips are usually manufactured by dividing a workpiece such as a silicon wafer on which a plurality of devices such as ICs (Integrated Circuits) are formed on the surface side.

[0003] In order to divide a workpiece, for example, a cutting device is used. The cutting device includes a chuck table having a holding surface for sucking and holding the workpiece. Above the chuck table, a cutting unit having a spindle to which a cutting blade is attached is provided.

[0004] When dividing a workpiece, usually, first, the back surface side of the workpiece is sucked and held by the holding surface, and the front surface side of the workpiece is exposed upward. Next, along a plurality of division planned lines set in a grid pattern on the surface of the workpiece, the cutting blade is sequentially cut into the workpiece to cut the workpiece, and the workpiece is divided into individual device chips.

[0005] When dividing a workpiece, in order to suppress the occurrence of cracks and chipping during cutting, after forming cutting grooves on each of the front and back surfaces, a processing method of cutting the workpiece so as to connect the cutting grooves to each other is known (for example, see Patent Document 1).

[0006] In the processing method described in Patent Document 1, on the front and back surfaces of the workpiece, V-shaped grooves having a V shape in a cross-sectional view are respectively formed at positions corresponding to each other in the thickness direction of the workpiece, and then the workpiece is cut so as to connect the V-shaped grooves on the front and back surfaces.

[0007] To that end, in the processing method described in Patent Document 1, first, the surface side of the workpiece on which multiple division lines are set is held by suction with a chuck table, and the back side of the workpiece is exposed upwards. Next, alignment marks (target marks) on the surface side are imaged through alignment windows and viewing windows formed at multiple locations on the chuck table.

[0008] After alignment, a V-shaped groove is formed on the back side of the workpiece along the planned division line. Then, the workpiece is flipped over, and a V-shaped groove is formed on the front side as well. Subsequently, the workpiece is cut using a cutting blade with a blade thickness smaller than the width of the V-shaped groove, so as to connect the V-shaped grooves located at corresponding positions in the thickness direction of the workpiece.

[0009] However, when cutting the back side of a workpiece using the cutting device described above, if there is distortion in the shape of the alignment marks on the front side, for example, the position of the center line of the V-shaped groove on the front side (i.e., the center line that passes through the center position of the width of the V-shaped groove in the width direction of the V-shaped groove perpendicular to the longitudinal direction of the V-shaped groove, and is parallel to the longitudinal direction) and the position of the center line of the V-shaped groove on the back side may be misaligned within a predetermined plane due to misalignment of the cutting blade.

[0010] Incidentally, when cutting a workpiece from its front surface to its back surface, the cutting blade may cut at an angle to the thickness direction of the workpiece, resulting in what is known as an oblique cut (see, for example, Patent Document 2). When an oblique cut occurs, the position of the center line of the cutting groove exposed on the back surface and the position of the center line of the cutting groove exposed on the front surface are usually misaligned within a predetermined plane.

[0011] Therefore, if the position of the center line of the cutting groove exposed on the surface and the position of the center line of the planned division line on the surface are made to coincide within a predetermined plane, then the position of the center line of the cutting groove exposed on the back surface and the position of the center line of the planned division line on the surface will be misaligned within that predetermined plane.

[0012] However, even when oblique cuts occur, it may be necessary to align the center line of the cutting groove exposed on the back surface with the center line of the planned division line on the front surface within a predetermined plane in order to meet the specifications of the device chip shape. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 6-275583 [Patent Document 2] Japanese Patent Publication No. 2020-113635 [Overview of the project] [Problems that the invention aims to solve]

[0014] This invention has been made in view of the aforementioned problems, and aims to correct the machining position so that the centerlines of two workpieces that need to coincide on both sides of the workpiece coincide if they are misaligned within a predetermined plane, and then proceed with machining. [Means for solving the problem]

[0015] According to one aspect of the present invention, a method for processing a workpiece, comprising: a first processing groove forming step in which, while holding the surface side of the workpiece and exposing the back side of the workpiece located opposite to the surface, a first processing groove having a depth that does not reach the surface side is formed using a first processing unit; and after the first processing groove forming step, while holding the workpiece with a holding table having a region formed of a transparent material, the first processing groove is imaged with a first imaging unit, and a second imaging unit is provided on the opposite side of the holding table from the first imaging unit. The imaging unit comprises: an imaging step of imaging a predetermined line provided on the surface and located in the thickness direction of the workpiece corresponding to the first machining groove; a detection step of detecting whether the position of the first center line of the first machining groove imaged by the first imaging unit and the position of the second center line of the predetermined line imaged by the second imaging unit coincide in a predetermined plane after the imaging step; and a correction step of correcting the machining position so that the position of the first center line and the position of the second center line do not coincide in the detection step. The process further comprises a second machining groove forming step, in which, prior to the imaging step, the workpiece is held on the holding table to expose the front side, and a second machining groove is formed using a second machining unit, which is located on the opposite side of the first machining groove in the thickness direction of the workpiece and has a depth that does not reach the first machining groove, wherein the predetermined line is the opening of the second machining groove located on the surface, the detection step detects whether the position of the first center line of the first machining groove imaged by the first imaging unit and the position of the second center line of the second machining groove imaged by the second imaging unit coincide in a predetermined plane, and the correction step corrects the machining position of the second machining unit. A method for processing a workpiece is provided.

[0017] Preferably, at least one of the first processing unit and the second processing unit has a cutting blade whose outer peripheral end in cross-sectional view is V-shaped, and at least one of the first processing groove and the second processing groove has a V-shaped cross-sectional view depending on the shape of the outer peripheral end of the cutting blade.

[0018] Preferably, at least one of the first processing unit and the second processing unit is a laser irradiation unit capable of irradiating a pulsed laser beam having a wavelength absorbed by the workpiece.

[0019] Preferably, the processing method further comprises a splitting step of dividing the workpiece with a third processing unit such that the first processing groove and the second processing groove, which are located at corresponding positions in the thickness direction of the workpiece, are connected. [Effects of the Invention]

[0023] In the processing method according to one aspect of the present invention, the first processing groove formed on the back surface side of the workpiece is imaged by the first imaging unit, and a predetermined line provided on the front surface of the workpiece and located at a position corresponding to the first processing groove in the thickness direction of the workpiece is imaged by the second imaging unit (imaging step).

[0024] After the imaging step, it is detected whether the position of the first center line of the first processing groove imaged by the first imaging unit and the position of the second center line of the predetermined line imaged by the second imaging unit coincide within a predetermined plane (detection step). And when the position of the first center line and the position of the second center line do not coincide, the processing position is corrected so as to coincide (correction step).

[0025] In this way, by directly observing the front and back surfaces of the workpiece, the deviation between the position of the first center line and the position of the second center line is detected. Therefore, even if a deviation occurs between the center lines, the workpiece can be processed after correcting so that the positions of the center lines coincide. Therefore, the processing accuracy of the workpiece can be improved.

[0026] In the processing method according to another aspect of the present invention, when the position of the first center line of the first processing groove imaged by the upper imaging unit and the position of the second center line of the division planned line specified based on the alignment mark imaged by the lower imaging unit do not coincide within a predetermined plane, the processing position is corrected so as to coincide.

[0027] In the processing method according to still another aspect of the present invention, when the position of the first center line of the first processing groove imaged by the lower imaging unit and the position of the second center line of the division planned line specified based on the alignment mark imaged by the upper imaging unit do not coincide within a predetermined plane, the processing position is corrected so as to coincide.

[0028] Therefore, even when diagonal cutting occurs, the position of the first center line and the position of the second center line can be made to coincide. In this way, the center lines that need to coincide on both sides of the workpiece can be made to coincide.

Brief Description of the Drawings

[0029] [Figure 1] It is a perspective view of a cutting device. [Figure 2] It is a perspective view of a workpiece unit. [Figure 3] It is a perspective view of a chuck table. [Figure 4] It is a side sectional view of a part of the chuck table. [Figure 5] It is an enlarged view of region A in FIG. 4. [Figure 6] It is an enlarged perspective view of the lower imaging unit. [Figure 7] It is a flowchart of the processing method. [Figure 8] It is a view showing the first processing groove forming step. [Figure 9] It is a cross-sectional view of the workpiece after the inversion step. [Figure 10] It is a view showing the second processing groove forming step. [Figure 11] It is a view showing the imaging step. [Figure 12] FIG. 12(A) is an example of an image obtained by the upper imaging unit, and FIG. 12(B) is an example of an image obtained by the lower imaging unit. [Figure 13] FIG. 13(A) is a cross-sectional view when the center lines of the processing grooves coincide, and FIG. 13(B) is a cross-sectional view when the center lines of the processing grooves are displaced. [Figure 14] It is a view showing an additional second processing groove forming step. [Figure 15] It is a view showing the dividing step. [Figure 16] It is a view showing the first processing groove forming step according to the second embodiment. [Figure 17] It is a view showing the second processing groove forming step according to the second embodiment. [Figure 18] It is a view showing the imaging step according to the second embodiment. [Figure 19] It is a view showing an additional second processing groove forming step according to the second embodiment. [Figure 20] This figure shows the division process according to the second embodiment. [Figure 21] This is a perspective view of a laser processing apparatus according to a third embodiment. [Figure 22] This figure shows the first groove formation process according to the third embodiment. [Figure 23] This figure shows the second groove formation process according to the third embodiment. [Figure 24] This figure shows the imaging process according to the third embodiment. [Figure 25] This figure shows an additional second groove formation step according to the third embodiment. [Figure 26] This figure shows the division process according to the third embodiment. [Figure 27] Figure 27(A) is a partial cross-sectional side view of the expansion device, etc., and Figure 27(B) is a diagram showing the division process according to the fourth embodiment. [Figure 28] This is a flowchart of the processing method according to the fifth embodiment. [Figure 29] This figure shows the first groove formation process according to the fifth embodiment. [Figure 30] This figure shows the imaging process according to the fifth embodiment. [Figure 31] Figure 31(A) is a cross-sectional view of the fifth embodiment when the positions of the centerlines coincide, and Figure 31(B) is a cross-sectional view of the fifth embodiment when the positions of the centerlines do not coincide. [Figure 32] This figure shows the first groove formation process according to the sixth embodiment. [Figure 33] This figure shows the imaging process according to the sixth embodiment. [Figure 34] This is a diagram showing the imaging process according to the seventh embodiment. [Modes for carrying out the invention]

[0030] An embodiment of one aspect of the present invention will be described with reference to the attached drawings. Figure 1 is a perspective view of a cutting apparatus 2 according to the first embodiment. In Figure 1, some of the components are shown as functional blocks.

[0031] As shown in Figure 1, the X-axis direction (machining feed direction), Y-axis direction (indexing feed direction), and Z-axis direction (vertical direction) are orthogonal to each other. The X-axis direction is parallel to the +X and -X directions. Similarly, the Y-axis direction is parallel to the +Y and -Y directions, and the Z-axis direction is parallel to the +Z and -Z directions.

[0032] The cutting device 2 includes a base 4 that supports each component. An opening 4a is formed in the front corner (+Y direction) of the base 4, and a cassette elevator (not shown) is provided inside the opening 4a. A cassette 6 for accommodating multiple workpieces 11 (see Figure 2) is placed on the upper surface of the cassette elevator.

[0033] The workpiece 11 includes, for example, a disc-shaped single-crystal substrate (wafer) formed of a semiconductor material such as silicon (Si) or silicon carbide (SiC). However, there are no restrictions on the shape, structure, size, etc., of the workpiece 11. The workpiece 11 may also have a substrate formed of other semiconductors, ceramics, resins, metals, or other materials.

[0034] As shown in Figure 2, multiple division lines 13 are set in a grid pattern on the surface 11a side of the workpiece 11. Devices such as ICs 15, alignment marks (not shown), etc. are formed in each region demarcated by the multiple division lines 13.

[0035] A tape (dicing tape) 17 with a diameter larger than the diameter of the workpiece 11 is attached to the surface 11a side. The tape 17 has a laminated structure of a base layer and an adhesive layer and is made of a transparent material that can transmit light in a predetermined wavelength range such as visible light and infrared light.

[0036] The base layer is made of, for example, polyolefin (PO). The adhesive layer is made of, for example, an adhesive resin such as ultraviolet (UV) curable acrylic resin. The surface 11a of the workpiece 11 is attached to the center of the adhesive layer of this tape 17.

[0037] One side of a ring-shaped metal frame 19 is attached to the outer circumference of the tape 17, forming a workpiece unit 21 in which the workpiece 11 is supported by the frame 19 via the tape 17.

[0038] Figure 2 is a perspective view of the workpiece unit 21. The workpiece unit 21 is housed in the cassette 6 with the back surface 11b of the workpiece 11, which is located on the opposite side from the front surface 11a, exposed.

[0039] As shown in Figure 1, a rectangular opening 4b is formed behind (-Y direction) the opening 4a. A disc-shaped chuck table (holding table) 10 is positioned in the opening 4b. An annular frame suction plate (not shown) with multiple suction ports formed along the circumferential direction is provided on the outer circumference of the chuck table 10.

[0040] Here, we will explain the chuck table 10 and other components in more detail with reference to Figures 3 to 6. Figure 3 is a perspective view of the chuck table 10, and Figure 4 is a partial cross-sectional side view of the chuck table 10. However, for convenience, hatching has been omitted in Figure 4.

[0041] Figure 5 is an enlarged view of area A in Figure 4. In Figure 5, some of the components are shown as functional blocks. The chuck table 10 has a disc-shaped holding member 12. The holding member 12 includes one substantially flat surface 12a and another substantially flat surface 12b located on the opposite side of the surface 12a.

[0042] The retaining member 12 is made of a transparent material that transmits visible light and infrared light (e.g., near-infrared light). The retaining member 12 is made of, for example, quartz glass, borosilicate glass, or soda glass, but may also be made of calcium fluoride, lithium fluoride, or magnesium fluoride.

[0043] Inside the holding member 12, a linear first suction passage 12c1 is formed so as to cross the central axis of the disc when the holding member 12 is viewed from above. In addition, a linear second suction passage 12c2 is formed in a plane substantially parallel to one surface 12a, perpendicular to the first suction passage 12c1.

[0044] The first suction passage 12c1 and the second suction passage 12c2 are connected to each other at a center point 12c3 located on the central axis of the disk. Multiple openings 12d are formed on the outer periphery of one surface 12a. Each opening 12d is formed to a predetermined depth, extending from one surface 12a to the other surface 12b.

[0045] Openings 12d are formed at both ends of the first suction passage 12c1 and at both ends of the second suction passage 12c2. Each opening 12d is connected by an outer peripheral suction passage 12e formed at a predetermined depth on the outer circumference of the holding member 12.

[0046] A suction passage 12f extending radially is formed on the outer circumference of the opening 12d, and a suction source 14, such as an ejector, is connected to the suction passage 12f (see Figure 5). When the suction source 14 is operated to generate negative pressure, negative pressure is generated at the opening 12d. Therefore, one surface 12a functions as a holding surface that sucks and holds the workpiece unit 21 (workpiece 11).

[0047] In the flow paths such as the first suction path 12c1, the second suction path 12c2, the opening 12d, the outer periphery suction path 12e, and the suction path 12f, some of the incident light is scattered or reflected. Therefore, when viewed from one surface 12a or the other surface 12b, the flow paths of the holding member 12 are not completely transparent, and may be translucent or opaque.

[0048] However, a predetermined area of ​​the retaining member 12, excluding these flow paths, is transparent from one surface 12a to the other surface 12b. For example, the area divided into four sections by the first suction passage 12c1 and the second suction passage 12c2, and located inside the outer peripheral suction passage 12e in the radial direction of the retaining member 12, is transparent from one surface 12a to the other surface 12b.

[0049] A cylindrical frame 16 made of a metal material such as stainless steel is provided on the outer circumference of the retaining member 12. An opening 16a is formed at the top of the frame 16 (see Figure 5), and the retaining member 12 is positioned to close this opening 16a.

[0050] The frame 16 is supported by an X-axis moving table 18, as shown in Figures 3 and 4. The X-axis moving table 18 includes a rectangular base plate 18a. The lower end of a rectangular side plate 18b is connected to the front (+Y direction) end of the base plate 18a.

[0051] The front end of the top plate 18c, which is rectangular like the bottom plate 18a, is connected to the upper end of the side plate 18b. The bottom plate 18a and the top plate 18c are arranged to overlap in the Z-axis direction, and the bottom plate 18a, side plate 18b, and top plate 18c form a space 18d that is open on both the rear (-Y direction) side and the X-axis direction.

[0052] The lower (-Z direction) side of the base plate 18a is slidably attached to a pair of X-axis guide rails 20 fixed to the upper surface of a stationary base (not shown). An X-axis linear scale 20a is provided near the X-axis guide rails 20.

[0053] A reading head (not shown) is provided on the underside of the X-axis moving table 18. By detecting the scale of the X-axis linear scale 20a using the reading head, the position (coordinates) of the X-axis moving table 18 in the X-axis direction and the amount of movement in the X-axis direction are calculated.

[0054] A nut portion (not shown) is provided on the underside of the base plate 18a, and a screw shaft 22, which is positioned approximately parallel to the X-axis direction, is rotatably connected to this nut portion via a ball (not shown). A motor 24 is connected to one end of the screw shaft 22.

[0055] When the motor 24 is operated, the screw shaft 22 rotates, and the X-axis moving table 18 moves along the X-axis direction. The X-axis moving table 18, a pair of X-axis guide rails 20, the screw shaft 22, the motor 24, etc. constitute the X-axis moving mechanism 26.

[0056] On the upper surface of the top plate 18c, the frame 16 is supported so as to be rotatable around a rotation axis that is substantially parallel to the Z-axis direction. The side of the frame 16 located above the top plate 18c functions as a pulley section 16b.

[0057] A rotary drive source 30, such as a motor, is provided on the outer side surface of the side plate 18b. A pulley 30a is provided on the rotating shaft of the rotary drive source 30. A belt 28 is stretched over the pulley 30a and the pulley portion 16b.

[0058] When the rotary drive source 30 is activated, the frame 16 rotates around a rotation axis that is approximately parallel to the Z-axis direction. By controlling the rotation of the pulley 30a, the chuck table 10 can rotate by any angle around the rotation axis.

[0059] An extension of the X-axis movement mechanism 26 in the X-axis direction is provided with a Y-axis movement mechanism 32 for moving the lower imaging unit 54 (first imaging unit) in the Y-axis direction. The Y-axis movement mechanism 32 includes a pair of Y-axis guide rails 34 that are substantially parallel to the Y-axis direction. The pair of Y-axis guide rails 34 are fixed to the upper surface of a stationary base (not shown).

[0060] A Y-axis movable table 36 is slidably mounted on a Y-axis guide rail 34. A nut portion (not shown) is provided on the underside of the Y-axis movable table 36, and a screw shaft 38, which is arranged substantially parallel to the Y-axis direction, is rotatably connected to this nut portion via a ball (not shown).

[0061] A motor 40 is connected to one end of the screw shaft 38. When the motor 40 rotates the screw shaft 38, the Y-axis moving table 36 moves along the Y-axis direction. A Y-axis linear scale (not shown) is provided near the Y-axis guide rail 34.

[0062] Furthermore, a reading head (not shown) is provided on the underside of the Y-axis moving table 36. By detecting the scale of the Y-axis linear scale with the reading head, the position (coordinates) of the Y-axis moving table 36 in the Y-axis direction and the amount of movement in the Y-axis direction are calculated.

[0063] A Z-axis movement mechanism 42 is provided on the upper surface of the Y-axis movement table 36. The Z-axis movement mechanism 42 has a support structure 42a fixed to the upper surface of the Y-axis movement table 36. As shown in Figure 6, a pair of Z-axis guide rails 44, which are arranged substantially parallel to each other in the Z-axis direction, are fixed to one surface of the support structure 42a.

[0064] A Z-axis moving plate 46 is slidably mounted on the Z-axis guide rail 44. A nut portion (not shown) is provided on the support structure 42a side of the Z-axis moving plate 46, and a screw shaft 48, which is arranged substantially parallel to the Z-axis direction, is rotatably connected to this nut portion via a ball (not shown).

[0065] A motor 50 is connected to the upper end of the screw shaft 48. When the motor 50 rotates the screw shaft 48, the Z-axis moving plate 46 moves along the Z-axis direction. A Z-axis linear scale (not shown) is provided near the Z-axis guide rail 44.

[0066] The Z-axis moving plate 46 is equipped with a reading head (not shown). By detecting the scale of the Z-axis linear scale with the reading head, the position (coordinates) of the Z-axis moving plate 46 in the Z-axis direction is calculated.

[0067] The lower imaging unit 54 is fixed to the Z-axis moving plate 46 via a support arm 52 whose longitudinal portion is positioned along the X-axis direction. Figure 6 is an enlarged perspective view of the lower imaging unit 54. The lower imaging unit 54 is a so-called microscope camera unit, including a low-magnification camera 56 and a high-magnification camera 58.

[0068] Each of the low-magnification camera 56 and the high-magnification camera 58 has a predetermined optical system such as a condensing lens and an image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor (neither of which are shown in the figure).

[0069] In this example, an image sensor capable of converting visible light into photoelectric energy is used. The lower imaging unit 54 is located below the chuck table 10 (i.e., on the opposite side of the upper imaging units 86a and 86b relative to the chuck table 10). Furthermore, the optical axes of each condensing lens are positioned approximately perpendicular to the other surface 12b of the holding member 12.

[0070] A lighting device 56a is provided to the side of the low-magnification camera 56 to irradiate visible light onto the workpiece 11 and the like positioned above it. Similarly, a lighting device 58a is also provided to the side of the high-magnification camera 58.

[0071] When imaging the workpiece 11 with the lower imaging unit 54, the X-axis moving table 18 is moved to position the lower imaging unit 54 in space 18d. Then, by imaging the workpiece 11 from below via the holding member 12, an image of the surface 11a can be obtained.

[0072] Now, returning to Figure 1, we will describe the other components of the cutting apparatus 2. On both sides of the top plate 18c in the X-axis direction, expandable bellows-like covers are attached in such a manner that they cover the opening 4b. In addition, a gate-shaped support structure 4c is provided above the opening 4b, straddling the opening 4b in the Y-axis direction.

[0073] Two machining unit movement mechanisms (indexing feed unit and depth feed unit) 60 are provided on one side of the support structure 4c in the -X direction. Each machining unit movement mechanism 60 shares a pair of Y-axis guide rails 62 fixed to one side of the support structure 4c.

[0074] A pair of Y-axis guide rails 62 are arranged substantially parallel to each other in the Y-axis direction. Two Y-axis movable plates 64 are attached to the pair of Y-axis guide rails 62 in a manner that allows them to slide independently of each other.

[0075] A nut portion (not shown) is provided on one surface of the Y-axis moving plate 64, and a screw shaft 66, which is arranged substantially parallel to the Y-axis direction, is rotatably connected to this nut portion via a ball (not shown). The nut portion of each Y-axis moving plate 64 is connected to a different screw shaft 66.

[0076] A motor 68 is connected to one end of each screw shaft 66. When the motor 68 rotates the screw shaft 66, the Y-axis moving plate 64 moves along the Y-axis direction.

[0077] One side of the Z-axis moving plate 70a is slidably attached to a pair of Z-axis guide rails 72 provided on the other side of the Y-axis moving plate 64 located on the rear (-Y direction) side.

[0078] Similarly, one side of the Z-axis moving plate 70b is slidably attached to a pair of Z-axis guide rails 72 provided on the other side of the Y-axis moving plate 64 located on the front (+Y direction) side.

[0079] Each of the Z-axis moving plates 70a and 70b is provided with a nut portion (not shown) on one side, and a screw shaft 74 is rotatably connected to the nut portion via a ball (not shown). Each screw shaft 74 is arranged substantially parallel to the Z-axis direction.

[0080] A motor 76 is connected to the upper end of the screw shaft 74. When the motor 76 rotates the screw shaft 74, the Z-axis moving plate 70a and the Z-axis moving plate 70b move along the Z-axis direction, respectively.

[0081] A first cutting unit (first machining unit, second machining unit) 78a is provided at the lower part of the Z-axis moving plate 70a, which is located on the rear (-Y direction) side. The first cutting unit 78a includes a cylindrical spindle housing 80a.

[0082] A portion of a cylindrical spindle 82a (see Figure 8) is rotatably housed within the spindle housing 80a. A rotational drive source (not shown), such as a motor, is provided at one end of the spindle 82a.

[0083] A first cutting blade 84a having an annular cutting edge is mounted on the other end of the spindle 82a. In this example, the first cutting blade 84a is a washer type (hubless type), but it may also be a hub type.

[0084] An upper imaging unit (second imaging unit) 86a is fixed to the lower part of the Z-axis moving plate 70a. In other words, the position of the upper imaging unit 86a is fixed relative to the first cutting unit 78a.

[0085] The upper imaging unit 86a is positioned above the chuck table 10. The upper imaging unit 86a is a so-called microscope camera unit. The upper imaging unit 86a has a predetermined optical system, including a condensing lens etc., whose optical axis is positioned approximately perpendicular to one surface 12a of the holding member 12, and an image sensor capable of photoelectric conversion of visible light etc. (neither is shown).

[0086] Similarly, a third cutting unit (third machining unit) 78b is provided at the bottom of the Z-axis moving plate 70b, which is positioned on the front (+Y direction) side. The third cutting unit 78b also includes a spindle housing 80b, within which a portion of a cylindrical spindle 82b (see Figure 15) is rotatably housed.

[0087] A rotational drive source (not shown), such as a motor, is provided at one end of the spindle 82b, and a third cutting blade 84b is mounted at the other end of the spindle 82b (see Figure 15). In this example, the third cutting blade 84b is a washer type (hubless type), but it may also be a hub type.

[0088] However, the blade thickness 84b1 of the third cutting blade 84b (see Figure 15) is thinner than the blade thickness 84a1 of the first cutting blade 84a (see Figure 8). Therefore, the width of the machining groove (cutting groove) formed when the workpiece 11 is cut with the third cutting blade 84b is smaller than the width 13a1 of the first machining groove (cutting groove) 13a formed with the first cutting blade 84a (see Figure 15).

[0089] An upper imaging unit 86b is provided at the lower part of the Z-axis moving plate 70b, with its position fixed relative to the third cutting unit 78b. The structure of the upper imaging unit 86b is substantially the same as that of the upper imaging unit 86a.

[0090] As shown in Figure 1, a circular opening 4d is provided behind (-Y direction) the opening 4b. A cleaning unit 90 is provided inside the opening 4d for cleaning the workpiece 11 after cutting with cleaning water such as pure water.

[0091] A housing (not shown) is provided on the base 4, and a touch panel 92 is provided on the front side (+Y direction) of the housing, which serves as both an input unit (i.e., an input interface) for the operator to input instructions and a display unit for displaying information to the operator.

[0092] The touch panel 92 displays images captured by, for example, the upper imaging units 86a and 86b and the lower imaging unit 54. Along with the image 88a captured by the upper imaging unit 86a, the touch panel 922a of the upper imaging unit 86a is displayed through image processing (see Figure 12(A)).

[0093] The reference line 92a is a straight line that crosses the center of the imaging area of ​​the upper imaging unit 86a and is approximately parallel to the X-axis direction. The upper imaging unit 86a functions as an eye for directly observing the workpiece 11.

[0094] Similarly, the touch panel 92 displays the reference line 92b along with the image 88b captured by the lower imaging unit 54, through image processing (see Figure 12(B)). Like the reference line 92a, the reference line 92b is a straight line that crosses the center of the imaging area of ​​the lower imaging unit 54 and is approximately parallel to the X-axis direction.

[0095] The lower imaging unit 54, like the upper imaging unit 86a, functions as an eye for directly observing the workpiece 11. Since the origin positions of the upper imaging unit 86a and the lower imaging unit 54 are pre-set to coincide, the reference lines 92a and 92b are pre-set to coincide with each other in the X-Y plane and will not shift.

[0096] The touch panel 92 displays images captured by the lower imaging unit 54 and the upper imaging units 86a and 86b, as well as processing conditions, a GUI (Graphical User Interface), and the like. The cutting device 2 includes a control unit 94 that controls the touch panel 92 and the like.

[0097] The control unit 94 also controls the suction source 14, the X-axis movement mechanism 26, the rotation drive source 30, the Y-axis movement mechanism 32, the Z-axis movement mechanism 42, the lower imaging unit 54, the processing unit movement mechanism 60, the first cutting unit 78a, the third cutting unit 78b, the upper imaging units 86a and 86b, etc.

[0098] The control unit 94 is composed of a computer including a processing unit such as a processor represented by a CPU (Central Processing Unit) and a storage device 96. The storage device 96 has a main memory such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), or ROM (Read Only Memory), and an auxiliary storage device such as flash memory, a hard disk drive, or a solid-state drive.

[0099] The auxiliary storage device stores software containing a predetermined program. The functions of the control unit 94 are realized by operating the processing unit according to this software. Next, a cutting method (processing method) for cutting the workpiece 11 using the cutting device 2 will be described.

[0100] Figure 7 is a flowchart of the cutting method according to the first embodiment. In order to cut the workpiece 11, first, with the back surface 11b side exposed upwards, the front surface 11a side is held by suction via the tape 17 using the chuck table 10 (holding step S10).

[0101] After the holding step S10, the first machining groove 13a is formed on the back surface 11b side using the first cutting unit 78a (first machining groove formation step S20). Figure 8 shows the first machining groove formation step S20.

[0102] In the first machining groove formation step S20, first, the lower imaging unit 54 images the surface 11a side and performs alignment. Next, the rotation drive source 30 is operated to make the division line 13 along the first direction approximately parallel to the X-axis direction (so-called θ alignment is performed).

[0103] Next, the first cutting blade 84a is positioned on the extension of one planned division line 13, and the lower end of the first cutting blade 84a, which rotates at high speed (e.g., 30,000 rpm), is positioned at a predetermined depth 23a where it does not reach the surface 11a from the back surface 11b.

[0104] In this state, while supplying cutting fluid such as pure water to the first cutting blade 84a, the X-axis moving table 18 is machined (i.e., moved along the X-axis) to form a first machining groove 13a (a so-called half-cut groove) having a predetermined depth 23a. The machining feed rate is, for example, 30 mm / s.

[0105] However, the depth 23a does not have to be half the thickness 11c of the workpiece 11. In this embodiment, the depth 23a is less than half the thickness 11c of the workpiece 11. For example, if the thickness 11c of the workpiece 11 is 100 μm, the depth 23a is set to 25 μm. However, the depth 23a may be adjusted as appropriate so as not to reach the surface 11a.

[0106] After forming one first machining groove 13a, the first cutting unit 78a is indexed and fed by a predetermined indexing feed amount to cut the back surface 11b along the other planned division lines 13 along the first direction.

[0107] Similarly, after cutting the back surface 11b along all remaining planned division lines 13 along the first direction, the chuck table 10 is rotated 90 degrees so that all planned division lines 13 along the second direction perpendicular to the first direction are approximately parallel to the X-axis direction.

[0108] Then, the back surface 11b is similarly cut along all the planned division lines 13 along the second direction to form the first machining groove 13a. After cutting the workpiece 11 along all the planned division lines 13 on the back surface 11b, the workpiece 11 is cleaned in the cleaning unit 90. After that, the workpiece unit 21 is removed from the cutting device 2.

[0109] Subsequently, as shown in Figure 9, another tape (dicing tape) 27 is attached to the back surface 11b and the other surface of the frame 19 to form a workpiece unit 31 in which the tape 27 is attached to the back surface 11b and the front surface 11a is exposed (reversal step S30).

[0110] Figure 9 is a cross-sectional view of the workpiece 11 after the inversion process S30. If the cutting device 2 has a tape replacement device, the inversion process S30 may be performed within the cutting device 2 without removing the workpiece unit 21 from the cutting device 2.

[0111] Tape 27, like tape 17, has a laminated structure consisting of a base layer and an adhesive layer, and is made of a transparent material that can transmit light in a predetermined wavelength range, such as visible light. After the inversion process S30, the back surface 11b side of the workpiece 11 is held by suction on the chuck table 10, and the front surface 11a side is exposed upwards.

[0112] In this state, the second machining groove formation process S40 is performed using the first cutting unit 78a. Figure 10 shows the second machining groove formation process S40. In the second machining groove formation process S40, as in the first machining groove formation process S20, alignment and θ adjustment are first performed with the upper imaging unit 86a.

[0113] Next, the first cutting blade 84a is positioned on the extension of one planned division line 13, and the lower end of the first cutting blade 84a, which rotates at high speed, is positioned at a predetermined depth 23b, where it does not reach the first machining groove 13a from the surface 11a.

[0114] Then, by feeding the X-axis moving table 18 while supplying cutting fluid in the same manner, a single second machining groove 13b is formed, which is located on the opposite side of the first machining groove 13a in the thickness direction 11d of the workpiece 11 and has a predetermined depth 23b that does not reach the first machining groove 13a.

[0115] Furthermore, when cutting the surface 11a, the rotational speed of the first cutting blade 84a is set to, for example, 30,000 rpm, and the machining feed rate is set to, for example, 30 mm / s.

[0116] The second machining groove 13b is also a so-called half-cut groove, similar to the first machining groove 13a. However, the depth 23b does not have to be half the thickness 11c of the workpiece 11. In this embodiment, the depth 23b is less than half the thickness 11c of the workpiece 11.

[0117] For example, if the thickness 11c of the workpiece 11 is 100 μm, the depth 23b is set to 25 μm. However, the depth 23b may be adjusted as appropriate, as long as it does not reach the first machining groove 13a.

[0118] After the second machining groove formation step S40, the upper imaging unit 86a images the second machining groove 13b on the surface 11a side, and the lower imaging unit 54 (for example, a high-magnification camera 58 and an illumination device 58a) images the first machining groove 13a on the back surface 11b side (imaging step S50).

[0119] Figure 11 shows the imaging process S50. The upper imaging unit 86a focuses on the surface 11a that is exposed above and images the elongated opening (i.e., predetermined line) 13b3 of the second processing groove 13b located on the surface 11a.

[0120] The aperture 13b3 is located on the surface 11a and is positioned in the thickness direction 11d to correspond to the first machining groove 13a. In the imaging step S50, similarly, the lower imaging unit 54 focuses on the back surface 11b via the tape 27 and images the elongated aperture 13a3 of the first machining groove 13a.

[0121] Figure 12(A) is an example of an image 88a of the surface 11a side acquired by the upper imaging unit 86a. In the image 88a shown in Figure 12(A), the second center line 13b2 of the second machining groove 13b coincides with the reference line 92a.

[0122] The second centerline 13b2 is located at the center in the width direction of the opening 13b3 in the second machining groove 13b, and is substantially parallel to the longitudinal direction of the second machining groove 13b which is perpendicular to the width direction. The second centerline 13b2 substantially corresponds to the center 84a2 in the thickness direction of the cutting edge of the first cutting blade 84a during cutting (see Figure 10).

[0123] Figure 12(B) is an example of an image 88b of the back surface 11b acquired by the lower imaging unit 54. In the image 88b shown in Figure 12(B), the first center line 13a2 of the first machining groove 13a coincides with the reference line 92b.

[0124] Similarly, the first centerline 13a2 is located at the center in the width direction of the opening 13a3 in the first machining groove 13a, and is substantially parallel to the longitudinal direction of the first machining groove 13a which is perpendicular to the width direction. The first centerline 13a2 substantially corresponds to the center 84a2 in the thickness direction of the cutting edge of the first cutting blade 84a during cutting (see Figure 8).

[0125] As mentioned above, reference lines 92a and 92b coincide in the X-Y plane, and images 88a and 88b are obtained by imaging the same region in the X-Y plane in different orientations along the Z axis.

[0126] After the imaging step S50, the control unit 94 detects the misalignment between the first machining groove 13a and the second machining groove 13b based on images 88a and 88b (detection step S60).

[0127] Specifically, in the detection step S60, the control unit 94 performs predetermined image processing on images 88a and 88b to detect whether the position of the first center line 13a2 of the first machining groove 13a and the position of the second center line 13b2 of the second machining groove 13b coincide in the X-Y plane (a predetermined plane).

[0128] For example, first, the positions (for example, coordinates with the center point 12c3 as the origin) of the first center line 13a2 of the first machining groove 13a and the second center line 13b2 of the second machining groove 13b are identified by image processing. Next, the length corresponding to the displacement between the first center line 13a2 and the second center line 13b2 is calculated.

[0129] The length corresponding to one pixel in images 88a and 88b is predetermined according to the camera's magnification, etc., so the amount of displacement is calculated based on the number of pixels between the first center line 13a2 and the second center line 13b2. The image processing and the program for calculating the amount of displacement are pre-stored in the auxiliary storage device of the storage device 96.

[0130] Figure 13(A) is an enlarged cross-sectional view of a portion of the workpiece 11 when the position of the first center line 13a2 of the first machining groove 13a and the position of the second center line 13b2 of the second machining groove 13b coincide in the X-Y plane. If they coincide (YES in S62), the process proceeds to the additional second machining groove forming step S80.

[0131] Figure 13(B) is an enlarged cross-sectional view of a portion of the workpiece 11 when the position of the first center line 13a2 of the first machining groove 13a and the position of the second center line 13b2 of the second machining groove 13b are misaligned in the X-Y plane.

[0132] Misalignment between centerlines can occur due to various reasons. For example, if the alignment marks formed on the surface 11a are distorted, the position where the first cutting blade 84a should cut and the position where the workpiece 11 is actually cut may be misaligned.

[0133] However, in this embodiment, the upper imaging unit 86a images the surface 11a side and the lower imaging unit 54 images the back surface 11b side, so the first machining groove 13a and the second machining groove 13b are directly observed, and this misalignment can be detected.

[0134] In Figure 13(B), vector B1 shows the amount and direction of deviation of the second center line 13b2 from the reference line 92b in the Y-axis direction. In detection step S60, if the position of the first center line 13a2 and the position of the second center line 13b2 do not coincide in the X-Y plane, the control unit 94 prompts the operator to correct the cutting position with an alarm.

[0135] In this specification, the statement that the positions of the first centerline 13a2 and the second centerline 13b2 do not coincide in the X-Y plane (i.e., are misaligned) means that the amount of misalignment in the Y-axis direction between the positions of the first centerline 13a2 and the second centerline 13b2 in the X-Y plane is greater than a first threshold (e.g., 5 μm).

[0136] If the amount of deviation is greater than the first threshold, the control unit 94 prompts the operator to correct the cutting position. The operator, while looking at the image 88a, operates the touch panel 92 to move the reference line 92a (i.e., the upper imaging unit 86a) to align the reference line 92a with the second center line 13b2 (correction step S70).

[0137] Based on the movement direction and distance of the reference line 92a in the correction process S70, the control unit 94 detects the amount and direction of displacement of the cutting position (vector B1 shown in Figure 13(B)) and stores this in the storage device 96.

[0138] During cutting after the correction process S70, the control unit 94 controls the machining unit movement mechanism 60 to counteract the amount and direction of the displacement, thereby correcting the position of the center 84a2 of the first cutting blade 84a (i.e., the machining position of the first cutting unit 78a). Specifically, the indexing feed amount is adjusted by adding the amount and direction of the displacement to a predetermined indexing feed amount.

[0139] This makes it possible to make the position of the first centerline 13a2 and the position of the second centerline 13b2 coincide in the X-Y plane during subsequent cutting (i.e., the additional second machining groove formation step S80).

[0140] When the correction process S70 is performed, the position of the first center line 13a2 and the position of the second center line 13b2 coincide in the X-Y plane, which means that the amount of deviation in the Y-axis direction between the position of the first center line 13a2 and the position of the second center line 13b2 in the X-Y plane is less than or equal to a second threshold (for example, 1 μm) which is smaller than the first threshold.

[0141] Note that in Figure 13(B), for the sake of simplicity, the reference line 92b and the first center line 13a2 of the first machined groove 13a are shown to coincide, but the reference line 92b and the first center line 13a2 may be misaligned.

[0142] If the reference line 92b and the first center line 13a2 are misaligned, and the reference line 92a and the second center line 13b2 are misaligned, both the amount and direction of the misalignment of the first center line 13a2 from the reference line 92a, and the amount and direction of the misalignment of the second center line 13b2 from the reference line 92b, are used to correct the machining position.

[0143] In any case, the amount and direction of the displacement of the second center line 13b2 relative to the position of the first center line 13a2 are detected in detection step S60, and this amount and direction of displacement are corrected in correction step S70.

[0144] Figure 14 shows the additional second machining groove formation step S80. In the additional second machining groove formation step S80, the first cutting unit 78a is indexed and fed sequentially in the Y-axis direction from the position of the second machining groove 13b formed in the second machining groove formation step S40 to form four additional second machining grooves 13b.

[0145] Once a total of five second machining grooves 13b have been formed in this manner, a splitting process S90 is started to divide the workpiece 11 so that the first machining groove 13a and the second machining grooves 13b, which are located at corresponding positions in the thickness direction 11d, are connected. Figure 15 shows the splitting process S90.

[0146] In the splitting process S90, the center 84b2 of the blade thickness 84b1 is positioned within the width 13a1, 13b1, and the lower end of the third cutting blade 84b, which rotates at high speed, is positioned on the surface 11a side of a predetermined depth 23a.

[0147] In this state, the workpiece 11 is divided by feeding the chuck table 10 while supplying cutting fluid. In the dividing process S90, for example, the rotational speed of the third cutting blade 84b is set to, for example, 30,000 rpm, and the machining feed rate is set to, for example, 30 mm / s.

[0148] In this embodiment, when the workpiece 11 is cut along the first second machining groove 13b by the third cutting unit 78b, the sixth second machining groove 13b is formed by the first cutting unit 78a. In other words, there is a time period in which the additional second machining groove formation step S80 and the division step S90 are performed in parallel.

[0149] After forming second machining grooves 13b along all remaining planned division lines 13 along the first direction, and further dividing the workpiece 11 so that the first machining grooves 13a and the second machining grooves 13b along the first direction are connected, the chuck table 10 is rotated 90 degrees.

[0150] Subsequently, second machining grooves 13b are formed along all planned division lines 13 along the second direction, and the workpiece 11 is further divided so that the first machining grooves 13a and the second machining grooves 13b along the second direction are connected.

[0151] In this embodiment, the workpiece 11 is machined so that the third cutting unit 78b follows the first cutting unit 78a along the Y-axis direction. However, the splitting step S90 may be started after the additional second machining groove forming step S80 is completed.

[0152] For example, if the workpiece 11 is made of a brittle material such as glass, which is more brittle than a single-crystal substrate made of silicon, starting the splitting process S90 after the additional second processing groove formation process S80 is completed can reduce the occurrence of chipping, cracking, etc.

[0153] As explained above, in the first embodiment, even if the position of the first center line 13a2 and the position of the second center line 13b2 are misaligned, the workpiece 11 can be cut after correcting the position so that the positions of the first center line 13a2 and the second center line 13b2 coincide from the time of cutting the next planned division line 13.

[0154] In addition, according to this processing method, by directly observing the first processing groove 13a and the second processing groove 13b, even if there is distortion in the shape of the alignment mark, the effect of the distortion in the shape of the alignment mark can be mitigated.

[0155] In this way, the machining accuracy of the workpiece 11 can be improved compared to when the first machining groove 13a and the second machining groove 13b are not directly observed. Specifically, the first center line 13a2 of the first machining groove 13a and the second center line 13b2 of the second machining groove 13b can be aligned with greater precision.

[0156] (First Modification) In the first embodiment, the imaging step S50 and the detection step S60 were performed only once, but they may be performed multiple times. Specifically, the imaging step S50 and the detection step S60 may be performed each time a predetermined number (for example, 5) of second processed grooves 13b are formed.

[0157] If the detection process S60 reveals a misalignment between the centerlines, the correction process S70 is performed. This increases the processing time, but it guarantees even higher precision machining.

[0158] (Second Modification) In the first groove formation step S20 of the first embodiment, the first cutting unit 78a was used as the first and second processing units. However, the first groove formation step S20 may be performed using other cutting devices similar to the cutting device 2.

[0159] When the first machining groove formation step S20 is performed using another cutting device, the chuck table provided on the other cutting device may be the chuck table 10 described above, or it may be a chuck table in which a porous plate made of porous ceramics is fixed to a disc-shaped recess of a metal frame.

[0160] When a porous plate made of porous ceramics is used as a chuck table, an infrared camera unit is used as an upper imaging unit to image the front surface 11a from the back surface 11. The infrared camera unit has a predetermined optical system and an image sensor capable of converting infrared light into photoelectric energy.

[0161] After the first machining groove formation step S20 using another cutting device, the first cutting unit 78a is used as the second machining unit in the second machining groove formation step S40 and the additional second machining groove formation step S80, and the third cutting unit 78b is used as the third machining unit in the division step S90.

[0162] Thus, when different cutting units are used in the first machining groove formation step S20 and the second machining groove formation step S40, the mounting of the cutting blade to the spindle may be normal for one cutting unit but abnormal for the other (i.e., the cutting blade is mounted to the spindle so that its side is at an angle to the spindle).

[0163] As a result, the positions of the first center line 13a2 and the second center line 13b2 may be misaligned in the X-Y plane. However, as described in the first embodiment, this misalignment can be corrected by going through the correction process S70.

[0164] (Second Embodiment) Next, a second embodiment will be described using Figures 16 to 20. In the second embodiment as well, the cutting device 2 described above is used to process the workpiece 11 according to the flow in Figure 7. Therefore, explanations that overlap with the first embodiment will be omitted.

[0165] In the second embodiment, the cutting blade 98a (see Figure 16) mounted on the first cutting unit (first processing unit, second processing unit) 78a has a V-shape at its outer peripheral end when viewed in cross-sectional view through a cross section passing through the radial center of the cutting blade 98a. This point differs from the first embodiment.

[0166] In other words, the cutting blade 98a has its center 98a2 of the blade thickness 98a1 protruding the most in the radial direction, and inclined surfaces are formed from the center 98a2 of the blade thickness 98a1 toward both sides of the annular shape of the cutting blade 98a. In the machining method of the second embodiment, the first machining groove forming step S20 is performed after the holding step S10.

[0167] Figure 16 shows the first machining groove forming step S20 according to the second embodiment. The bottom of the first machining groove 13a formed in the first machining groove forming step S20 has a V-shape in cross-sectional view in a cross section perpendicular to the longitudinal direction of the first machining groove 13a, according to the shape of the outer peripheral end of the cutting blade 98a.

[0168] In the first machining groove formation step S20, the first machining groove 13a is formed along all the planned division lines 13, and then the second machining groove formation step S40 is performed after the reversal step S30 (see Figure 9). Figure 17 shows the second machining groove formation step S40 according to the second embodiment.

[0169] The bottom of the second machining groove 13b also has a V-shape in cross-sectional view. After forming one second machining groove 13b in the second machining groove forming step S40, the imaging step S50 is performed. Figure 18 shows the imaging step S50 according to the second embodiment.

[0170] After the imaging step S50, the detection step S60 is performed. In the detection step S60, it is detected whether the position of the first center line 13a2 of the first machining groove 13a and the position of the second center line 13b2 of the second machining groove 13b coincide in the X-Y plane (a predetermined plane).

[0171] If the position of the first center line 13a2 and the position of the second center line 13b2 coincide in the X-Y plane, the process proceeds to the additional second machining groove formation step S80. Conversely, if the position of the first center line 13a2 and the position of the second center line 13b2 do not coincide in the X-Y plane, the process proceeds to the correction step S70 and then to the additional second machining groove formation step S80.

[0172] Figure 19 shows an additional second machining groove forming step S80 according to the second embodiment. Because the modification step S70 has been performed, in the additional second machining groove forming step S80, the position of the first center line 13a2 and the position of the second center line 13b2 can be made to coincide in the X-Y plane.

[0173] In the second embodiment as well, once the five second machining grooves 13b are formed, the splitting process S90 is started. Figure 20 shows the splitting process S90 in the second embodiment. However, as described above, the splitting process S90 may be started after the completion of the additional second machining groove forming process S80.

[0174] In the second embodiment as well, the machining accuracy of the workpiece 11 can be improved compared to the case where the first machining groove 13a and the second machining groove 13b are not directly observed. In addition, depending on the V-shape of each machining groove, chamfered portions can be formed on the outer periphery of the surface 11a and back surface 11b of the finally manufactured device chip (not shown).

[0175] By forming a chamfered portion, the occurrence of cracks and chipping on the outer periphery of the surface 11a and back surface 11b can be suppressed compared to when no chamfered portion is formed. Furthermore, the first and second modifications may also be applied to the second embodiment.

[0176] (Third Modification) At least one of the cutting blades (not shown) attached to the cutting unit (first processing unit) that performs the first processing groove formation step S20 and the cutting blade attached to the first cutting unit (second processing unit) 78a may have a V-shape at its outer peripheral end in cross-sectional view.

[0177] In this case, the machining groove formed by the cutting blade having a V-shaped outer edge in cross-sectional view, i.e., at least one of the first machining groove 13a and the second machining groove 13b, is machined to have a V-shaped cross-sectional view.

[0178] (Third Embodiment) Next, a third embodiment will be described with reference to Figures 21 to 26. In the third embodiment, a first processing groove 13a (see Figure 22) and a second processing groove 13b (see Figure 23) are formed by ablation processing of the workpiece 11 by irradiating it with a laser beam L (see Figure 21).

[0179] Figure 21 is a perspective view of the laser processing apparatus 102 according to the third embodiment. Components that are the same as or corresponding to those in the cutting apparatus 2 are denoted by the same reference numerals, and redundant explanations are omitted.

[0180] In the laser processing apparatus 102, the lower imaging unit 54 is fixed to the stationary base 104. However, the lower imaging unit 54 may be provided in a manner that allows it to move in the X-axis direction or the Y-axis direction.

[0181] An X-axis movable table 18 is provided above the stationary base 104. The X-axis movable table 18 is positioned so that the lower imaging unit 54 can enter the space 18d from the area opposite to the side plate 18b of the X-axis movable table 18.

[0182] The X-axis moving table 18 is movable along the X-axis direction by an X-axis moving mechanism 26. A pair of X-axis guide rails 20 are fixed to the Y-axis moving table 106. The Y-axis moving table 106 is slidably mounted on a pair of Y-axis guide rails 108 fixed to the upper surface of a stationary base 104.

[0183] A Y-axis linear scale 108a is provided near the Y-axis guide rail 108, which is used to detect the Y-axis position of the Y-axis moving table 106. A nut portion (not shown) is provided on the underside of the Y-axis moving table 106.

[0184] A screw shaft 110, positioned approximately parallel to the Y-axis guide rail 108, is connected to the nut portion in a manner that allows it to rotate via a ball (not shown). A motor 112 is connected to one end of the screw shaft 110. The Y-axis guide rail 108, screw shaft 110, motor 112, etc., constitute the Y-axis direction movement mechanism 114.

[0185] A column 116 is provided adjacent to the lower imaging unit 54 in the +Y direction, projecting upward from the upper surface of the stationary base 104. The column 116 is provided with a casing 118 having a longitudinal portion substantially parallel to the X-axis direction.

[0186] The casing 118 is provided with at least a portion of the laser irradiation unit 120. The laser irradiation unit (first processing unit, second processing unit) 120 is capable of irradiating the workpiece 11 with a pulsed laser beam L having a wavelength (e.g., 355 nm) that is absorbed by the workpiece 11.

[0187] The laser irradiation unit 120 includes a laser oscillator 120a, etc. A head portion 122, including a focusing lens 122a, is provided at the tip of the laser irradiation unit 120 in the X-axis direction.

[0188] The laser beam emitted from the laser oscillator 120a is focused by the focusing lens 122a and irradiated downward from the head unit 122. In Figure 21, the laser beam L irradiated downward from the head unit 122 is shown by a dashed arrow. An upper imaging unit 86a is provided at the tip of the casing 118, adjacent to the head unit 122.

[0189] As shown in Figure 21, the upper imaging unit 86a and the lower imaging unit 54 (for example, the high-magnification camera 58 and the illumination device 58a) are positioned in the same Y-axis direction, but their positions in the X-axis direction are misaligned.

[0190] Therefore, it is not possible to simultaneously observe corresponding positions in the thickness direction 11d of the workpiece 11 held by the chuck table 10. However, the positional relationship between the upper imaging unit 86a and the lower imaging unit 54 with respect to the chuck table 10 is predetermined.

[0191] Therefore, by moving the X-axis moving table 18 along the X-axis, the same region in the X-Y plane, with the center point 12c3 of the holding member 12 (see Figure 3) as the reference, can be observed by the upper imaging unit 86a and the lower imaging unit 54.

[0192] As shown above, the reference line 92a displayed in image 88a and the reference line 92b displayed in image 88b are located at the same coordinate position in the image and do not shift relative to each other.

[0193] In the third embodiment, the workpiece 11 is processed according to the flow shown in Figure 7. In the processing method of the third embodiment, prior to the holding step S10, a first protective film 29a (see Figure 22) made of a water-soluble resin is provided on the back surface 11b side.

[0194] Next, after the surface 11a side is held by suction with the chuck table 10 (i.e., after the holding step S10), the first machining groove forming step S20 is performed. Figure 22 shows the first machining groove forming step S20 according to the third embodiment.

[0195] In the first groove formation step S20, the focusing point of the laser beam L is positioned on the back surface 11b, and laser processing is performed under the following processing conditions, for example.

[0196] Laser beam wavelength: 355nm Average output: 2W Pulse repetition frequency: 200kHz Machining feed rate: 400 mm / s Number of passes: 1

[0197] In the first machining groove formation step S20, after forming the first machining grooves 13a along all the planned division lines 13, the first protective film 29a is cleaned and removed using a spinner cleaning device (not shown).

[0198] Next, in the inversion process S30, the workpiece unit 31 is formed, the tape 27 is attached to the back surface 11b side, and a second protective film 29b (see Figure 23) is formed on the front surface 11a side.

[0199] The second protective film 29b, like the first protective film 29a, has the function of preventing debris generated during the ablation process (for example, molten material constituting the workpiece 11) from adhering to the workpiece surface.

[0200] The second protective film 29b and the first protective film 29a described above can be formed by applying a solution containing a water-soluble resin such as polyvinylpyrrolidone or polyvinyl alcohol and a light absorber, and then drying it.

[0201] After forming a second protective film 29b on the surface 11a side, the second machining groove formation step S40 is performed. Figure 23 is a diagram showing the second machining groove formation step S40 according to the third embodiment. In the second machining groove formation step S40, one second machining groove 13b is formed under the machining conditions described above.

[0202] After the second machining groove formation step S40, the imaging step S50 is performed. Figure 24 shows the imaging step S50 according to the third embodiment. In the imaging step S50, the first machining groove 13a and the second machining groove 13b, which are located at corresponding positions in the thickness direction 11d, are imaged.

[0203] After the imaging step S50, the detection step S60 is performed. In the detection step S60, it is detected whether the position of the first center line 13a2 of the first machining groove 13a and the position of the second center line 13b2 of the second machining groove 13b coincide in the X-Y plane (a predetermined plane).

[0204] If the position of the first center line 13a2 and the position of the second center line 13b2 coincide in the X-Y plane, the process proceeds to the additional second machining groove formation step S80. Conversely, if the position of the first center line 13a2 and the position of the second center line 13b2 do not coincide in the X-Y plane, the process proceeds to the correction step S70 and then to the additional second machining groove formation step S80.

[0205] Figure 25 shows an additional second machining groove forming step S80 according to the third embodiment. By going through the modification step S70, the additional second machining groove forming step S80 makes it possible to make the position of the first center line 13a2 and the position of the second center line 13b2 coincide in the X-Y plane.

[0206] After forming the second machining grooves 13b along all the planned division lines 13, the second protective film 29b is cleaned and removed using a spinner cleaning device (not shown). Then, the workpiece unit 31 is transported to the cutting device 2.

[0207] In the cutting device 2, the workpiece 11 is cut using the third cutting unit 78b so that the first machining groove 13a and the second machining groove 13b are connected (splitting step S90). Figure 26 shows the splitting step S90 of the third embodiment.

[0208] In the third embodiment as well, the machining accuracy of the workpiece 11 can be improved compared to the case where the first machining groove 13a and the second machining groove 13b are not directly observed. Incidentally, in the third embodiment, a laser irradiation unit 120 was used as the first and second machining units.

[0209] However, at least one of the first and second processing units may be a laser irradiation unit 120. For example, if one of the first and second processing units is a laser irradiation unit 120, the other of the first and second processing units may be a first cutting unit 78a.

[0210] (Fourth Modification) In the division step S90 of the above-described embodiment and modification, the workpiece 11 was cut using a third cutting unit 78b having a relatively thin blade thickness 84b1. However, the division step S90 may also be performed by ablation processing on the workpiece 11.

[0211] (Fourth Embodiment) Next, a fourth embodiment will be described using Figures 27(A) and 27(B). In the fourth embodiment, the division process S90 is performed using the expansion device 130. This is the point that differs from the embodiments and modifications described above.

[0212] Figure 27(A) is a partial cross-sectional side view of the expansion device 130, etc. The expansion device 130 has a cylindrical drum 132 having a diameter larger than the diameter of the workpiece 11. Multiple rollers 134 are provided at approximately equal intervals along the circumferential direction of the drum 132 at the upper end of the drum 132.

[0213] In the radial direction of the drum 132, an annular frame support base 136 is provided on the outside of the drum 132. On the upper surface of the frame support base 136, a plurality of clamps 138 are provided to hold the frame 19 of the workpiece unit 31 placed on the frame support base 136.

[0214] Furthermore, the frame support base 136 is supported by a plurality of legs 140 arranged at approximately equal intervals along the circumferential direction of the frame support base 136. Each leg 140 can be raised and lowered by a lifting mechanism such as an air cylinder.

[0215] In the splitting process S90, as shown in Figure 27(A), the upper end of the drum 132 and the upper surface of the frame support base 136 are brought to approximately the same height, and the workpiece unit 31 after the additional second machining groove forming process S80 is placed on the drum 132 and the frame support base 136.

[0216] The workpiece 11 already has a first machining groove 13a and a second machining groove 13b formed in it such that the distance between the bottom of the first machining groove 13a and the bottom of the second machining groove 13b is less than or equal to a predetermined distance (for example, 50 μm or less).

[0217] After the workpiece unit 31 is placed, the lifting mechanisms are activated to pull down the legs 140, causing the frame support base 136 to be pulled down relative to the drum 132. As a result, as shown in Figure 27(B), the tape 27 expands radially, and the undivided region between the first machining groove 13a and the second machining groove 13b in the thickness direction 11d is divided.

[0218] Figure 27(B) shows the splitting process S90 according to the fourth embodiment. In the splitting process S90, the workpiece 11 is split into a plurality of device chips 33 using the expansion device 130. By widening the spacing between the device chips 33 at the same time as splitting, there is an advantage that the subsequent device chip 33 pickup process becomes easier.

[0219] (Fifth Embodiment) Next, a fifth embodiment will be described using Figures 28 to 31(B). In the fifth embodiment, when forming the first machining groove 13a on the back surface 11b side using the cutting device 2 described above, an imaging step S50, a detection step S60, a correction step S70, etc., are performed. This is the point that differs from the embodiments described above.

[0220] Figure 28 is a flowchart of the processing method according to the fifth embodiment. In the fifth embodiment, in the first processing groove forming step S22 after the holding step S10, only one first processing groove 13a is formed on the back surface 11b side (see Figure 29). Figure 29 is a diagram showing the first processing groove forming step S22 according to the fifth embodiment.

[0221] After the first machining groove formation step S22, as shown in Figure 30, the upper imaging unit (first imaging unit) 86a images the first machining groove 13a, and the lower imaging unit (second imaging unit) 54 images the division line (predetermined line) 13 located in the thickness direction 11d that corresponds to the first machining groove 13a (imaging step S50).

[0222] Figure 30 shows the imaging process S50 according to the fifth embodiment. In the fifth embodiment, the upper imaging unit 86a functions as the first imaging unit, and the lower imaging unit 54 functions as the second imaging unit.

[0223] After the imaging process S50, the control unit 94 detects the misalignment between the first processing groove 13a and the planned division line 13 based on the image 88a obtained by the upper imaging unit 86a and the image 88b obtained by the lower imaging unit 54 (detection process S60).

[0224] Figures 31(A) and 31(B) are enlarged cross-sectional views showing the detection process S60. In Figures 31(A) and 31(B), the upper imaging unit 86a and the lower imaging unit 54 are at the same position in the X-Y plane, with the workpiece 11 and the chuck table 10 in between.

[0225] However, this is merely a diagram for convenience, and it means that the lower imaging unit 54 is configured to image the area on the front surface 11a side that corresponds to the area on the back surface 11b side that is imaged by the upper imaging unit 86a in the X-Y plane.

[0226] In detection step S60, similar to the first embodiment, the control unit 94 performs image processing to detect whether the position of the first center line 13a2 of the first machining groove 13a and the position of the center line 13c of the division line 13 coincide in the X-Y plane (a predetermined plane).

[0227] The center line 13c of the planned division line 13 is a hypothetical straight line located at the center of the planned division line 13 in the width direction and approximately parallel to the longitudinal direction of the planned division line 13.

[0228] Figure 31(A) is an enlarged cross-sectional view of a portion of the workpiece 11 in the fifth embodiment, where the position of the first center line 13a2 of the first machining groove 13a and the position of the center line 13c of the division line 13 coincide in the X-Y plane. If they coincide (YES in S62), the process proceeds to the additional first machining groove forming step S72.

[0229] Figure 31(B) is an enlarged cross-sectional view of a portion of the workpiece 11 in the fifth embodiment, where the position of the first center line 13a2 of the first machining groove 13a and the position of the center line 13c of the division line 13 are misaligned in the X-Y plane.

[0230] In Figure 31(B), vector C1 shows the amount and direction of deviation of the first center line 13a2 from the reference line 92a in the Y-axis direction. If, in detection step S60, the position of the first center line 13a2 and the position of the center line 13c do not coincide in the X-Y plane, the process proceeds to correction step S70, as in the first embodiment.

[0231] During cutting after the correction process S70, the control unit 94 corrects the position of the center 84a2 of the first cutting blade 84a (i.e., the machining position of the first cutting unit 78a) so as to cancel out the amount and direction of displacement corresponding to vector C1.

[0232] This allows the position of the first center line 13a2 and the position of the center line 13c to coincide in the X-Y plane during subsequent cutting (i.e., the additional first machining groove formation step S72). In Figure 31(B), the reference line 92b and the center line 13c are shown to coincide for simplicity of explanation, but the reference line 92b and the center line 13c may be misaligned.

[0233] In any case, the amount and direction of the displacement of the position of the center line 13c relative to the position of the first center line 13a2 are detected in detection step S60, and this amount and direction of displacement are corrected in correction step S70.

[0234] In the additional first machining groove forming step S72, the first cutting unit 78a is indexed and fed sequentially in the Y-axis direction from the position of the first machining groove 13a formed in the first machining groove forming step S22, and additional first machining grooves 13a are formed along all remaining division lines 13 along the first direction.

[0235] Although not shown in Figure 28, after forming the first machining grooves 13a along all the planned division lines 13 along the first direction, the chuck table 10 is rotated 90 degrees. Then, similarly, the first machining grooves 13a are formed along the planned division lines 13 along the second direction perpendicular to the first direction, via steps S22 to S72.

[0236] In the fifth embodiment, the misalignment of the first centerline 13a2 and the centerline 13c can be detected by directly observing the surface 11a and the back surface 11b. If the position of the first centerline 13a2 and the position of the centerline 13c are misaligned, the workpiece 11 can be cut after correcting the position so that the positions of the first centerline 13a2 and the centerline 13c coincide from the time of cutting the next planned division line 13.

[0237] In addition, this processing method allows for the direct observation of the surface 11a and back surface 11b of the workpiece 11, thereby mitigating the effects of any distortion in the alignment mark shape, even if such distortion exists.

[0238] In the fifth embodiment, as in the second embodiment, the first processing groove 13a may be V-shaped in cross-section, and as in the third embodiment, the first processing groove 13a may be formed by laser ablation.

[0239] (Sixth Embodiment) Next, the sixth embodiment will be described with reference to Figures 32 and 33. In the sixth embodiment, the workpiece 11 is processed according to the flow shown in Figure 28 using the cutting device 2 described above. Therefore, explanations that overlap with the fifth embodiment will be omitted.

[0240] In the sixth embodiment, in the first machining groove forming step S22 following the holding step S10, a first machining groove 43 is formed that has a depth reaching from the back surface 11b to the front surface 11a of the workpiece 11. This is a difference from the fifth embodiment.

[0241] In the first machining groove formation step S22, first, only one first machining groove 43, known as a full-cut groove, is formed (see Figure 32). Figure 32 is a diagram showing the first machining groove formation step S22 according to the sixth embodiment. However, as shown in Figure 32, the first machining groove 43 may be inclined with respect to the thickness direction of the workpiece 11 (for example, the Z-axis direction) (so-called oblique cut).

[0242] For example, so-called oblique cutting may occur due to reasons such as the first cutting blade 84a being mounted at an angle to the spindle 82a, the first cutting blade 84a being unevenly worn, or the cutting resistance of the workpiece 11 being relatively large.

[0243] Even when such diagonal cuts occur, it may be necessary to align the center line (first center line) 45c of the width 45b of the planned division line 45a on the surface 11a with the center line (second center line) 43c of the width 43b of the opening 43a in the first processed groove 43 exposed on the back surface 11b.

[0244] The center line 43c is located at the center of the opening 43a in the width direction and is approximately parallel to the longitudinal direction perpendicular to the width direction of the opening 43a. Similarly, the center line 45c is located at the center of the planned division line 45a in the width direction and is approximately parallel to the longitudinal direction perpendicular to the width direction of the planned division line 45a.

[0245] In this embodiment, after the first machining groove formation step S22, as shown in Figure 33, while the surface 11a is held by the chuck table 10, the first machining groove 43 exposed on the back surface 11b is imaged by the upper imaging unit 86a, and the vicinity of the planned division line 45a is imaged by the lower imaging unit 54 (imaging step S50).

[0246] Figure 33 shows the imaging process S50 according to the sixth embodiment. The imaging field of each of the lower imaging units 54 may be smaller than the width 45b of the division line 45a, which includes the first processing groove 43 exposed on the surface 11a side.

[0247] In this case, even if the lower imaging unit 54 images the division line 45a, it is not possible to identify the center line 45c of the width 45b of the division line 45a. Therefore, in the imaging step S50 of this embodiment, the lower imaging unit 54 images the alignment marks 45 provided near the division line 45a on the surface 11a side.

[0248] After the imaging process S50, the control unit 94 performs image processing to determine the position coordinates of the center line 45c of the planned division line 45a based on the position coordinates of the alignment mark 45. The distance from the alignment mark 45 to the center line 45c is pre-registered in the cutting device 2.

[0249] Furthermore, the control unit 94 similarly identifies the coordinates of the center line 43c on the back surface 11b side of the first machining groove 43 by image processing. Subsequently, the control unit 94 detects whether the position of the center line 43c and the position of the center line 45c coincide in the X-Y plane (a predetermined plane) (detection step S60).

[0250] In Figures 32 and 33, the amount and direction of the displacement of centerline 43c from centerline 45c in the Y-axis direction are shown by vector D1. If the position of centerline 43c and the position of centerline 45c coincide in the X-Y plane (YES in S62), the process proceeds to the additional first machining groove formation step S72.

[0251] If the positions of the center line 43c and the center line 45c do not coincide in the X-Y plane, the process proceeds to correction step S70. During cutting after correction step S70, the control unit 94 corrects the position of the first cutting blade 84a (i.e., the machining position of the first cutting unit 78a) so as to cancel out the amount and direction of the displacement of the center line 43c and the center line 45c.

[0252] As a result, in subsequent cutting operations, the center line 43c of the opening 43a on the back surface 11b can be aligned with the position projected onto the back surface 11b from the center line 45c of the planned division line 45a on the front surface 11a.

[0253] (Seventh Embodiment) Next, the seventh embodiment will be described using Figure 34. In the seventh embodiment, the tape 17 is attached to the back surface 11b side instead of the front surface 11a side, and in the holding step S10 and the first processing groove forming step S22, the back surface 11b side is held by suction, and the front surface 11a side is exposed.

[0254] This aspect differs from the sixth embodiment. Therefore, explanations that overlap with the sixth embodiment are omitted. In the seventh embodiment, in the first machining groove forming step S22, a first machining groove 43 is formed having a depth that reaches from the surface 11a to the back surface 11b of the workpiece 11.

[0255] In addition, during the imaging process S50, while the back surface 11b is held in place by suction, the first processing groove 43 reaching the back surface 11b is imaged by the lower imaging unit, and the alignment marks 45 near the division line 45a are imaged by the upper imaging unit 86a (imaging process S50).

[0256] The control unit 94 identifies the coordinates of the center line 45c of the planned division line 45a on the surface 11a side and the coordinates of the center line 43c on the back surface 11b side of the first machining groove 43, and detects whether the position of the center line 43c and the position of the center line 45c coincide in the X-Y plane (a predetermined plane) (detection step S60).

[0257] Figure 34 shows the imaging step S50 according to the seventh embodiment. In Figure 34, the amount and direction of the displacement of the center line 43c from the center line 45c in the Y-axis direction are shown by vector D2. If the position of the center line 43c and the position of the center line 45c coincide in the X-Y plane (YES in S62), the process proceeds to an additional first machining groove forming step S72.

[0258] If the positions of the center line 43c and the center line 45c do not coincide in the X-Y plane, the process proceeds to correction step S70. During cutting after correction step S70, the control unit 94 corrects the position of the first cutting blade 84a (i.e., the machining position of the first cutting unit 78a) so as to cancel out the amount and direction of the displacement of the center line 43c and the center line 45c.

[0259] As a result, in subsequent cutting operations, the center line 43c of the opening 43a on the back surface 11b can be aligned with the position projected onto the back surface 11b from the center line 45c of the planned division line 45a on the front surface 11a.

[0260] Furthermore, the structures, methods, etc., relating to the above-described embodiments and modifications can be modified as appropriate without departing from the scope of the present invention. The above-described embodiments and modifications may also be combined as appropriate. [Explanation of symbols]

[0261] 2: Cutting device, 4: Base, 4a, 4b: Opening, 4c: Support structure, 4d: Opening 6: Cassette, 10: Chuck table (holding table) 11: Workpiece, 11a: Front surface, 11b: Back surface 11c: thickness, 11d: thickness direction 12: Holding member, 12a: One side, 12b: Other side 12c1: 1st suction path, 12c2: 2nd suction path, 12c3: Center point, 12d: Opening 12e: Peripheral suction path, 12f: Suction path 13: Planned division line (designated line) 13a: First machining groove, 13a1: Width, 13a2: First centerline 13b: Second machining groove, 13b1: Width, 13b2: Second centerline 13a3: Opening, 13b3: Opening (predetermined line), 13c: Center line 14: Suction source, 16: Frame, 16a: Opening, 16b: Pulley section 15: Device, 17: Tape, 19: Frame, 21: Workpiece Unit 18: X-axis movement table 18a: Base plate, 18b: Side plate, 18c: Top plate, 18d: Space 20: X-axis guide rail, 20a: X-axis linear scale, 22: Screw shaft 23a, 23b: Depth 24: Motor, 26: X-axis movement mechanism 27: Tape, 29a: First protective film, 29b: Second protective film, 31: Workpiece unit 28: Belt, 30: Rotary drive source, 30a: Pulley 32: Y-axis movement mechanism, 34: Y-axis guide rail, 36: Y-axis movement table 33: Device chip 38: Screw shaft, 40: Motor 42: Z-axis movement mechanism, 42a: Support structure, 44: Z-axis guide rail 43: First machining groove, 43a: Opening, 43b: Width, 43c: Centerline 45: Alignment marks, 45a: Planned division lines, 45b: Width, 45c: Centerline 46: Z-axis movement plate, 48: Screw shaft, 50: Motor 52: Support arm, 54: Lower imaging unit 56: Low-magnification camera, 56a: Lighting device 58: High-magnification camera, 58a: Lighting device 60: Processing unit moving mechanism, 62: Y-axis guide rail, 64: Y-axis moving plate 66: Screw shaft, 68: Motor 70a, 70b: Z-axis moving plate 72: Z-axis guide rail, 74: Screw shaft, 76: Motor 78a: First cutting unit (first processing unit, second processing unit) 78b: Third cutting unit (third processing unit) 80a, 80b: Spindle housing, 82a, 82b: Spindle 84a: First cutting blade, 84a1: Blade thickness, 84a2: Center 84b: Third cutting blade, 84b1: Blade thickness, 84b2: Center 86a: Upper imaging unit, 86b: Upper imaging unit 88a, 88b: Images 90: Cleaning unit, 92: Touch panel, 92a, 92b: Reference lines 94: Control unit, 96: Storage device 98a: Cutting blade, 98a1: Blade thickness, 98a2: Center 102: Laser processing device, 104: Stationary base 106: Y-axis moving table, 108: Y-axis guide rail, 108a: Y-axis linear scale 110: Screw shaft, 112: Motor, 114: Y-axis direction moving mechanism 116: Column, 118: Casing 120: Laser irradiation unit (first processing unit, second processing unit) 120a: Laser oscillator, 122: Head part, 122a: Condensing lens 130: Expansion device, 132: Drum, 134: Roller, 136: Frame support base 138: Clamp, 140: Legs A: Area, B1, C1, D1, D2: Vectors L: Laser beam S10: Holding process, S20, S22: First processing groove formation process, S30: Reversal process S40: Second processing groove formation process S50: Imaging process, S60: Detection process, S70: Correction process S72: Additional first machining groove formation step, S80: Additional second machining groove formation step S90:Dividing process

Claims

1. A method for processing a workpiece, A first machining groove forming step is performed by holding the surface side of the workpiece and exposing the back side of the workpiece located opposite to the surface, and forming a first machining groove having a depth that does not reach the surface side using a first machining unit, After the first machining groove forming step, the workpiece is held in a holding table having a region formed of a transparent material, and the first machining groove is imaged with a first imaging unit, and a second imaging unit, which is provided on the opposite side of the holding table from the first imaging unit, is used to image a predetermined line provided on the surface and located in the thickness direction of the workpiece that corresponds to the first machining groove, in an imaging step, After the imaging step, a detection step is performed to detect whether the position of the first center line of the first processed groove, which was imaged by the first imaging unit, and the position of the second center line of the predetermined line, which was imaged by the second imaging unit, coincide within a predetermined plane. In the detection step, if the position of the first center line and the position of the second center line do not coincide, a correction step is performed to adjust the machining position so that they coincide. Equipped with, Prior to the imaging step, the process further comprises a second machining groove forming step in which, with the back side of the workpiece held by the holding table and the front side exposed, a second machining groove is formed using a second machining unit, which is located on the opposite side of the first machining groove in the thickness direction of the workpiece and has a depth that does not reach the first machining groove. The predetermined line is the opening of the second machining groove located on the surface, In this detection step, it is detected whether the position of the first center line of the first machining groove, as captured by the first imaging unit, and the position of the second center line of the second machining groove, as captured by the second imaging unit, coincide within a predetermined plane. A method for processing a workpiece, characterized in that the processing position of the second processing unit is corrected in the correction step.

2. At least one of the first processing unit and the second processing unit has a cutting blade whose outer peripheral end has a V-shape in cross-sectional view. The method for machining a workpiece according to claim 1, characterized in that at least one of the first machining groove and the second machining groove has a V-shape in cross-sectional view, depending on the shape of the outer peripheral end of the cutting blade.

3. The method for processing a workpiece according to claim 1, characterized in that at least one of the first processing unit and the second processing unit is a laser irradiation unit capable of irradiating a pulsed laser beam having a wavelength absorbed by the workpiece.

4. A method for processing a workpiece according to any one of claims 1 to 3, further comprising a division step of dividing the workpiece with a third processing unit such that the first processing groove and the second processing groove, which are located at corresponding positions in the thickness direction of the workpiece, are connected.

Images