Kerf check method and processing device

Abstract

To facilitate kerf checks of wafers with TEGs placed on them.SOLUTION: A kerf check method includes a street storage step of imaging a wafer (60) with cameras (52, 53) to determine and store streets (63) along which a kerf (67) is to be formed by processing units (11, 12), a TEG position coordinate storage step of imaging the streets stored in the street storage step with the cameras to acquire and store position coordinates of a TEG (66), a kerf formation step of forming a kerf on the streets stored in the street storage step with the processing units, and a kerf check step of checking the kerf at a location where there is no TEG in the kerf using the position coordinates of the TEG.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a kerf check method for checking the state of a kerf formed in a wafer, and a processing apparatus for forming a kerf in a wafer by a processing unit. [Background technology]

[0002] As disclosed in Patent Documents 1, 2, and 3, processing devices that form kerfs (machined grooves) along the streets of wafers by cutting or laser processing perform kerf checks by capturing an image of the kerf to check the size of chipping, etc.

[0003] In wafers where test elements called TEGs (Test Element Groups) are placed on the streets to evaluate device characteristics, the TEGs may be peeled off from the wafer during the process of forming a kerf. In this case, if a kerf check is performed in an area that includes the TEGs, the area where the TEGs have peeled off may be recognized as chipping, and the chipping may be mistakenly determined to be a large kerf.

[0004] To prevent such a problem, a known countermeasure is to form a kerf in a portion of the wafer where there is no TEG, and have the worker register the kerf in advance as an area for kerf checking, as disclosed in Patent Document 4. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-130806 [Patent Document 2] Japanese Patent Publication No. 2023-050704 [Patent Document 3] Japanese Patent Application Publication No. 2019-054096 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-197702 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the task of having an operator pre-register areas on the wafer where there is no TEG is time-consuming, and this causes a problem of reduced productivity in the processing equipment.

[0007] Therefore, there is a problem to be solved to facilitate kerf checking of a wafer on which a TEG is placed. [Means for solving the problem]

[0008] One aspect of the present invention is a kerf checking method for checking a kerf formed by a processing unit on a wafer having a TEG arranged on a street, the method comprising: a street storing step of imaging the wafer with a camera and determining and storing the street on which the processing unit will form the kerf; a TEG position coordinate storing step of imaging the street stored in the street storing step with the camera to obtain and store the position coordinate of a TEG; a kerf forming step of forming a kerf by the processing unit on the street stored in the street storing step; and a kerf checking step of using the position coordinate of the TEG to check the kerf at a location where the TEG is not present in the kerf.

[0009] One aspect of the present invention is a wafer processing method in which a first kerf with a bottom is formed on a wafer having a TEG arranged on a street by a first processing unit, and a second kerf is formed in the first kerf by a second processing unit.The kerf check method for the kerf formed by the second processing unit includes a storage step of imaging the wafer with a camera to find areas on the street where the TEG is absent and storing the areas where the TEG is absent, a kerf forming step of forming a kerf on the surface of the wafer by the second processing unit in the area where the first kerf is not formed and where the TEG is absent that was stored in the storage step, and a kerf check step of performing a kerf check on the kerf.

[0010] One aspect of the present invention is a processing apparatus comprising a chuck table that holds a wafer with a TEG placed on a street, a processing unit that forms a kerf on the wafer, and a camera that images the wafer, and further comprising: a street memory unit that images the wafer with the camera and performs pattern matching with alignment marks formed on the wafer to determine and store streets to be processed; a TEG position coordinate memory unit that images the TEG on the street with the camera and acquires and stores the position coordinates of the TEG; a kerf formation control unit that forms a kerf on the street by the processing unit; and a kerf check control unit that images the kerf with the camera and checks the kerf at a location where there is no TEG.

[0011] One aspect of the present invention is a processing apparatus comprising a chuck table that holds a wafer with a TEG placed on a street, a first processing unit that forms a first kerf in the wafer, a second processing unit that forms a second kerf in the wafer, and a camera that images the wafer, and further comprising: a memory unit that images the wafer with the camera and stores areas where there is no TEG; a kerf formation control unit that forms a kerf on the surface of the wafer by the second processing unit in the area where there is no first kerf and where there is no TEG stored in the memory unit; and a kerf check control unit that performs a kerf check on the kerf. [Effects of the Invention]

[0012] According to the above-described kerf check method and processing apparatus, the kerf check is automatically performed in a place where there is no TEG, so that the kerf check of a wafer with a TEG placed on the street can be easily performed without being affected by TEG peeling or the like. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. [Figure 2] FIG. 1 is a perspective view showing a wafer before a kerf is formed. [Figure 3]FIG. 10 is a perspective view showing a state in which a kerf check is being performed on a full-cut groove formed along a street of a wafer. [Figure 4] FIG. 10 is a perspective view showing a state in which a kerf check is being performed on a half-cut groove formed along a street of a wafer. [Figure 5] FIG. 10 is a perspective view showing a state in which a step cut groove is formed along a street of a wafer. [Figure 6] FIG. 10 is a perspective view of a state in which a check kerf is formed by a second cutting blade in a non-street portion of the wafer. [Figure 7] FIG. 10 is a perspective view showing a state in which a kerf check is performed on a check kerf formed in a portion of the wafer other than the street. [Figure 8] FIG. 10 is a perspective view showing a state in which a check kerf is formed on the street of the wafer by the second cutting blade. [Figure 9] FIG. 10 is a perspective view showing a state in which a kerf check is performed on a check kerf formed on a street of a wafer. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a kerf check method and processing device to which the present invention is applied will be described with reference to the accompanying drawings. The processing device 10 shown in Fig. 1 is a cutting device that cuts a wafer 60, which is a workpiece, to form a kerf (processed groove). The X-axis and Y-axis directions of the processing device 10 are horizontal directions, and the X-axis and Y-axis directions are perpendicular to each other. The Z-axis direction is the up-down direction, with the +Z direction being upward and the -Z direction being downward.

[0015] 2 shows a wafer 60 before cutting by the processing device 10. The disk-shaped wafer 60 is supported on a ring-shaped frame 62 via a tape 61 having an area larger than that of the wafer 60. The tape 61 is attached to the bottom surface of the wafer 60 and the bottom surface of the frame 62. The kerf check method and processing device of the present invention can also be applied when processing a wafer 60 that is not attached to the frame 62.

[0016] 2, the surface (top surface) of the wafer 60 has a plurality of device regions partitioned into a grid by streets 63 extending in the X-axis direction and the Y-axis direction, and a chip 64 is formed in each device region. On the outer periphery of the wafer 60, there is a peripheral region 65 where no chips 64 are formed.

[0017] TEGs (Test Element Groups) 66 are arranged in some of the grid-like streets 63. The TEGs 66 are test elements for evaluating device characteristics before the wafer 60 is cut. A plurality of TEGs 66 are distributed and arranged at a plurality of locations on the wafer 60. In the configuration example shown in FIG. 2, a TEG 66 is provided near each end of each street 63 extending in the X-axis direction, and furthermore, TEGs 66 are provided at two locations near the center of the wafer 60.

[0018] Although not shown in the figure, alignment marks serving as positional indicators are formed on the surface of the wafer 60. The alignment marks may be dedicated marks arranged on the streets 63, or may be specific keeper patterns present on the chip 64.

[0019] As shown in Fig. 1, the processing device 10 includes a first processing unit 11 and a second processing unit 12. Using a first cutting blade 13 (see Figs. 3 to 6 and 8) included in the first processing unit 11 and a second cutting blade 14 (see Figs. 1, 3 to 6 and 8) included in the second processing unit 12, the wafer 60 is cut along the streets 63 to form a kerf, which is a processed groove.

[0020] Types of kerfs formed by the processing apparatus 10 include a full-cut groove 67 shown in FIG. 3, a half-cut groove 68 shown in FIG. 4, and a step-cut groove 69 shown in FIG. 5. The full-cut groove 67 is a groove that penetrates the wafer 60 in the thickness direction (Z-axis direction). The half-cut groove 68 is a groove with a bottom that is formed partway through the thickness direction (Z-axis direction) of the wafer 60. The step-cut groove 69 is a groove with a two-stage structure that has a first kerf 70 with a bottom that is formed on the front side of the wafer 60 and a second kerf 71 that is formed on the bottom surface of the first kerf 70. The width of the second kerf 71 is equal to or less than the width of the first kerf 70.

[0021] By changing the cutting depth of the first cutting blade 13 or the second cutting blade 14 in the Z-axis direction of the wafer 60, it is possible to select between forming a full-cut groove 67 or a half-cut groove 68. Therefore, when the kerf to be formed is a full-cut groove 67 or a half-cut groove 68, the processing device 10 may be configured to include only one of the first cutting blade 13 and the second cutting blade 14. By including both the first cutting blade 13 and the second cutting blade 14, as in the processing device 10 shown in FIG. 1, dual cutting is possible, in which the same full-cut groove 67 or half-cut groove 68 is simultaneously formed on two different streets 63, thereby improving processing efficiency.

[0022] The step cut groove 69 is formed by forming a first kerf 70 and a second kerf 71 using a first cutting blade 13 and a second cutting blade 14. For example, as shown in Fig. 5, the first kerf 70 is first formed using the first cutting blade 13, which has a width (thickness) in the Y-axis direction larger than that of the second cutting blade 14, and then the second kerf 71 is formed on the bottom surface of the formed first kerf 70 using the second cutting blade 14.

[0023] The method of forming a kerf in the wafer 60 may be laser processing using irradiation of a laser beam, in addition to cutting processing using a cutting blade. In other words, the processing device 10 shown in Fig. 1 is an example of a device for forming a kerf by cutting processing, and in the present invention, the processing device for forming a kerf in a wafer is not limited to a cutting device.

[0024] That is, a cutting blade may be used to form the first kerf and a laser beam may be used to form the second kerf, or a laser beam may be used to form the first kerf and a cutting blade may be used to form the second kerf, or a laser beam may be used to form both the first and second kerfs.

[0025] The overall configuration of the processing apparatus 10 will be described mainly with reference to Figure 1. The processing apparatus 10 includes a chuck table 20 that holds a wafer 60. The chuck table 20 is connected to a suction source (not shown), and air is sucked from a holding surface 21 by operation of the suction source, allowing the wafer 60 to be suction-held on the holding surface 21. A plurality of clamps 22 that hold a frame 62 are arranged around the chuck table 20.

[0026] The chuck table 20 is moved in the X-axis direction by a table feed mechanism 23. The X-axis direction is a processing feed direction in which the wafer 60 held on the chuck table 20, the first processing unit 11, and the second processing unit 12 are moved relatively to each other, and the wafer 60 is cut along streets 63 extending in the X-axis direction. The table feed mechanism 23 includes a pair of guide rails 24 extending in the X-axis direction and a ball screw 25. A base 26 that supports the chuck table 20 is supported by the guide rails 24 so as to be movable in the X-axis direction. A ball screw 25 is threadedly engaged with the base 26, and when the ball screw 25 is rotated by a motor 27, the base 26 moves in the X-axis direction together with the chuck table 20.

[0027] The chuck table 20 can be rotated around an axis facing the Z-axis direction relative to the base portion 26 by a table rotation mechanism 28 equipped with a motor.

[0028] The first processing unit 11 and the second processing unit 12 are arranged opposite each other in the Y-axis direction. The chuck table 20, which is moved in the X-axis direction by a table feed mechanism 23, can be positioned in a mounting / dismounting area on the +X-direction side and a processing area on the -X-direction side. In the mounting / dismounting area, the wafer 60 is mounted on and removed from the chuck table 20. In the processing area, the chuck table 20 is positioned below the first processing unit 11 and the second processing unit 12, and the wafer 60 held on the chuck table 20 can be cut using the first processing unit 11 and the second processing unit 12.

[0029] The first machining unit 11 has a ring-shaped first cutting blade 13 (see FIGS. 3 to 6 and 8) attached to the end of the first spindle 15, which is a rotation axis extending in the Y-axis direction, on the +Y-direction side. When the first spindle 15 is rotated by the spindle motor 16, the first cutting blade 13 rotates together with the first spindle 15.

[0030] The second machining unit 12 has a ring-shaped second cutting blade 14 (see FIGS. 1, 3 to 6, and 8) attached to the end of the second spindle 17, which is a rotation axis extending in the Y-axis direction, on the -Y direction side. When the second spindle 17 is rotated by the spindle motor 18, the second cutting blade 14 rotates together with the second spindle 17.

[0031] A gate-shaped column 30 is provided that straddles in the Y-axis direction above the chuck table 20, which is moved in the X-axis direction by the table feed mechanism 23. The column 30 supports a Y-axis movement mechanism 31 for moving the first machining unit 11 in the Y-axis direction, a Z-axis movement mechanism 32 for moving the first machining unit 11 in the Z-axis direction, a Y-axis movement mechanism 33 for moving the second machining unit 12 in the Y-axis direction, and a Z-axis movement mechanism 34 for moving the second machining unit 12 in the Z-axis direction.

[0032] A pair of guide rails 35 extending in the Y-axis direction are attached to the +X-direction side surface of column 30. Ball screws 36 and 37 each extending in the Y-axis direction are disposed between the pair of guide rails 35. Ball screw 36 is rotationally driven by motor 38, and ball screw 37 is rotationally driven by a motor (not shown).

[0033] Y-axis moving table 40 and Y-axis moving table 41 are supported movably in the Y-axis direction via a pair of guide rails 35. A ball screw 36 is threadedly engaged with a screw hole (not shown) provided in Y-axis moving table 40, and when ball screw 36 rotates, Y-axis moving table 40 moves in the Y-axis direction. A ball screw 37 is threadedly engaged with a screw hole (not shown) provided in Y-axis moving table 41, and when ball screw 37 rotates, Y-axis moving table 41 moves in the Y-axis direction.

[0034] A pair of guide rails 42 extending in the Z-axis direction are attached to the +X-direction side surface of Y-axis moving table 40. A ball screw 43 extending in the Z-axis direction is disposed between the pair of guide rails 42. Ball screw 43 is rotationally driven by a motor 44. Z-axis moving table 45 is supported via the pair of guide rails 42 so as to be movable in the Z-axis direction. Ball screw 43 is threadedly engaged with a screw hole (not shown) provided in Z-axis moving table 45, and when ball screw 43 rotates, Z-axis moving table 45 moves in the Z-axis direction.

[0035] A pair of guide rails 46 extending in the Z-axis direction are attached to the +X-direction side surface of Y-axis moving table 41. A ball screw 47 extending in the Z-axis direction is disposed between the pair of guide rails 46. Ball screw 47 is rotationally driven by a motor 48. A Z-axis moving table 49 is supported via the pair of guide rails 46 so as to be movable in the Z-axis direction. The ball screw 47 is threadedly engaged with a screw hole (not shown) provided in Z-axis moving table 49, and when ball screw 47 rotates, Z-axis moving table 49 moves in the Z-axis direction.

[0036] The first machining unit 11 is supported on the lower end of the Z-axis moving table 45. The first machining unit 11 includes a spindle housing 50 that houses a first spindle 15 and a spindle motor 16, and the spindle housing 50 is connected to the lower end of the Z-axis moving table 45.

[0037] The Y-axis movement mechanism 31 is configured by a structure that moves the Y-axis movement table 40 in the Y-axis direction, and the Z-axis movement mechanism 32 is configured by a structure that moves the Z-axis movement table 45 in the Z-axis direction. By moving the Y-axis movement table 40 in the Y-axis direction, the position of the first machining unit 11 changes in the Y-axis direction, and by moving the Z-axis movement table 45 in the Z-axis direction, the position of the first machining unit 11 changes in the Z-axis direction.

[0038] The second machining unit 12 is supported at the lower end of the Z-axis moving table 49. The second machining unit 12 includes a spindle housing 51 that houses the second spindle 17 and the spindle motor 18, and the spindle housing 51 is connected to the lower end of the Z-axis moving table 49.

[0039] The Y-axis moving mechanism 33 is configured by a structure that moves the Y-axis moving table 41 in the Y-axis direction, and the Z-axis moving mechanism 34 is configured by a structure that moves the Z-axis moving table 49 in the Z-axis direction. By moving the Y-axis moving table 41 in the Y-axis direction, the position of the second machining unit 12 changes in the Y-axis direction, and by moving the Z-axis moving table 49 in the Z-axis direction, the position of the second machining unit 12 changes in the Z-axis direction.

[0040] A camera 52 is attached to the spindle housing 50 of the first processing unit 11. A camera 53 is attached to the spindle housing 51 of the second processing unit 12. The cameras 52 and 53 are each capable of capturing images of a wafer 60 held on the chuck table 20 and positioned below the first processing unit 11 or the second processing unit 12.

[0041] The processing apparatus 10 is controlled by a control unit 80. The control unit 80 has a processor that generates signals for controlling each part of the processing apparatus 10, and a memory that stores various information used by the processor. The processor controls the operation of each part of the processing apparatus 10 by reading and executing programs stored in the memory. Therefore, when describing the operation of each part of the processing apparatus 10, unless a controlling entity is specified, it is assumed that the operation is performed under the control of the control unit 80.

[0042] The control unit 80 has, as functional blocks, a memory unit 81, a kerf formation control unit 82, and a kerf check control unit 83. The memory unit 81 includes a street memory unit 84 and a TEG position coordinate memory unit 85.

[0043] The flow of processing the wafer 60 using the processing device 10 configured as above will be described below. Here, an outline of the cutting process using the first cutting blade 13 and the second cutting blade 14 will be described, and the specific shapes of the kerfs formed by the cutting process and the kerf check method for each shape of kerf will be described later.

[0044] The chuck table 20 is positioned in the attachment / detachment area on the +X direction side, and the wafer 60 is placed on the holding surface 21 of the chuck table 20. The wafer 60 is held on the holding surface 21 via tape 61 attached to the underside. A suction source (not shown) is operated to apply suction force to the holding surface 21, thereby suction-holding the wafer 60. In addition, the frame 62 is held by multiple clamps 22. After the wafer 60 has been held on the chuck table 20 in this manner, the control unit 80 operates the table feed mechanism 23 to move the chuck table 20 to the processing area on the -X direction side.

[0045] The control unit 80 uses cameras 52 and 53 to capture images of the wafer 60 on the chuck table 20 positioned in the processing area, recognizes alignment marks (not shown) on the surface of the wafer 60, and aligns the positions of the first cutting blade 13 of the first processing unit 11 and the second cutting blade 14 of the second processing unit 12 with the street 63 to be processed.

[0046] With the first cutting blade 13 and the second cutting blade 14 positioned above one end in the X-axis direction of the street 63 to be machined, the control unit 80 drives the spindle motors 16 and 18 to rotate the first cutting blade 13 and the second cutting blade 14, and also operates the Z-axis movement mechanisms 32 and 34 to lower the first machining unit 11 and the second machining unit 12 in the -Z direction. The amount of lowering of the first machining unit 11 and the second machining unit 12 is set appropriately depending on the depth of the kerf to be formed.

[0047] The control unit 80 operates the table feed mechanism 23 to move the chuck table 20 in the X-axis direction. For example, the control unit 80 moves the chuck table 20 from a state in which the chuck table 20 is located on the +X-direction side of the first processing unit 11 and the second processing unit 12 to the -X-direction side. This movement of the chuck table 20 causes the rotating first cutting blade 13 and second cutting blade 14 to move relatively in the X-axis direction while cutting into the wafer 60 on the chuck table 20, thereby performing cutting processing along the streets 63.

[0048] When the cutting process by the first cutting blade 13 and the second cutting blade 14 reaches the end of the street 63 extending in the X-axis direction, the control unit 80 operates the Z-axis movement mechanism 32 and the Z-axis movement mechanism 34 to raise the first machining unit 11 and the second machining unit 12 in the +Z direction. Next, the control unit 80 operates the Y-axis movement mechanism 31 and the Y-axis movement mechanism 33 to move the first machining unit 11 and the second machining unit 12 a predetermined amount in the Y-axis direction, and position the first cutting blade 13 and the second cutting blade 14 above one end of the next uncut street 63. Then, the control unit 80 operates the Z-axis movement mechanism 32 and the Z-axis movement mechanism 34 to lower the first machining unit 11 and the second machining unit 12 in the -Z direction, and the table feed mechanism 23 moves the chuck table 20 in the X-axis direction, so that the rotating first cutting blade 13 and the second cutting blade 14 perform cutting along the street 63.

[0049] When cutting along all of the streets 63 aligned in the Y-axis direction is complete, the control unit 80 retracts the first cutting blade 13 and the second cutting blade 14 above the wafer 60, and then operates the table rotation mechanism 28 to rotate the chuck table 20 by 90 degrees. This rotation of the chuck table 20 causes the multiple uncut streets 63 extending in the X-axis direction to line up in the Y-axis direction. Next, using the same procedure as above, the first cutting blade 13 and the second cutting blade 14 sequentially cut the multiple uncut streets 63.

[0050] When cutting of all the streets 63 of the wafer 60 is completed, the control unit 80 operates the table feed mechanism 23 to move the chuck table 20 to the attachment / detachment area on the +X direction side. The suction holding of the wafer 60 on the holding surface 21 of the chuck table 20 and the fixation of the frame 62 by the clamps 22 are released, and the wafer 60 after cutting is carried out from the chuck table 20.

[0051] As described above, the processing device 10 performs cutting along each street 63 of the wafer 60 to form a kerf, which is a processed groove. The processing device 10 also performs a kerf check to confirm the state of the formed kerf. In the kerf check, the camera 52 or the camera 53 captures an image of the kerf to confirm the size of chipping and the positional deviation of the kerf relative to the street 63 and the chip 64.

[0052] In the kerf check, in addition to observing the state of chipping in the kerf, the amount of misalignment between the kerf and the hairline, which is the reference line for the image capture position of cameras 52 and 53, is confirmed. The amount of misalignment between the hairline and the kerf in the Y-axis direction detected in the kerf check is stored in the memory of control unit 80. Then, an adjustment (hairline alignment) is performed to align the image capture position of cameras 52 and 53 with the position of the kerf, thereby correcting the misalignment, so that the amount of misalignment is eliminated.

[0053] 3 shows an example of forming a kerf in a wafer 60, in which a full-cut groove 67 is formed along a street 63. The full-cut groove 67 is a groove that penetrates the wafer 60 in the thickness direction (Z-axis direction), and completely separates adjacent chips 64 across the full-cut groove 67.

[0054] 4 shows an example of forming a kerf in a wafer 60, in which a half-cut groove 68 is formed along a street 63. The half-cut groove 68 is a bottomed groove that does not penetrate the wafer 60 in the thickness direction (Z-axis direction).

[0055] Although Figures 3 and 4 show a full-cut groove 67 and a half-cut groove 68 formed along one street 63, a kerf check may also be performed when two or more kerfs (full-cut grooves 67 and half-cut grooves 68) are formed on the wafer 60 by the first cutting blade 13 and the second cutting blade 14.

[0056] Next, a kerf check method will be described that targets full-cut grooves 67 or half-cut grooves 68. Note that full-cut grooves 67 and half-cut grooves 68 can be formed by either the first machining unit 11 or the second machining unit 12, and the description will be given to include both cases where a kerf is formed by the first machining unit 11 and cases where a kerf is formed by the second machining unit 12, but it is also possible to form a kerf or perform a kerf check using only either the first machining unit 11 (including camera 52) or the second machining unit 12 (including camera 53).

[0057] [Street Memory Process] A street storage step is performed before forming a kerf in the wafer 60. The street storage step is executed under the control of the street storage unit 84 of the control unit 80. The street storage unit 84 captures an image of the wafer 60 using the camera 52 or 53, detects alignment marks (not shown) formed on the wafer 60 from the captured image by pattern matching, determines the streets 63 to be machined using the positions of the alignment marks as reference coordinates, and stores the position coordinates in memory.

[0058] [TEG position coordinate storage process] Next, a TEG position coordinate storage step is performed. The TEG position coordinate storage step is executed under the control of the TEG position coordinate storage unit 85 of the control unit 80. The street 63 stored in the previous street storage step is imaged by the camera 52 or the camera 53, and the position coordinates of the TEG 66 on the street 63 are acquired and stored in memory. For example, on the street 63 on which the full-cut groove 67 shown in FIG. 3 or the half-cut groove 68 shown in FIG. 4 is to be formed, TEGs 66 are arranged at four locations at different positions in the X-axis direction before cutting (see FIG. 2). The TEG position coordinate storage unit 85 acquires the position coordinates in the X-axis direction and the Y-axis direction for all TEGs 66 on the street 63 based on the image captured by the camera 52 or the camera 53, and stores the position coordinate data of each TEG 66 in memory.

[0059] 3 and 4. This imaging range S covers only a portion of the longitudinal direction of the street 63, so in the TEG position coordinate storage step, the relative positions of the cameras 52 and 53 with respect to the wafer 60 are changed to capture an image of the entire longitudinal direction (X-axis direction) of the street 63 stored in the street storage step. Specifically, by moving the chuck table 20 in the X-axis direction using the table feed mechanism 23, the entire street 63 extending in the X-axis direction can be imaged, and the position coordinates of all TEGs 66 present on the street 63 can be obtained.

[0060] [Kerf forming process] Following the TEG position coordinate storage step, a kerf forming step is performed. The kerf forming step is executed under the control of a kerf forming control unit 82 of the control unit 80. In the kerf forming step, the kerf forming control unit 82 controls the operations of the first machining unit 11, the second machining unit 12, the table feed mechanism 23, the Y-axis movement mechanism 31, the Z-axis movement mechanism 32, the Y-axis movement mechanism 33, the Z-axis movement mechanism 34, and the like, to form kerfs (full-cut grooves 67 and half-cut grooves 68) using the first cutting blade 13 and the second cutting blade 14 along the streets 63 stored in the previous street storage step.

[0061] [Kerf check process] After the kerf forming step is completed, a kerf check step is performed. The kerf check step is executed under the control of the kerf check control unit 83 of the control unit 80. In the kerf check step, the position coordinates of the TEG 66 stored in the previous TEG position coordinate storage step are used to perform a kerf check on the kerfs (full-cut grooves 67 and half-cut grooves 68) formed in the kerf forming step where the TEG 66 is not present.

[0062] More specifically, the kerf check control unit 83 reads out the position coordinates of the TEG 66 stored in the memory in the TEG position coordinate storage step, and sets the relative positions of the cameras 52 and 53 with respect to the wafer 60 so that the imaging range S of the cameras 52 and 53 does not include the position coordinates of the location where the TEG 66 existed before the kerf was formed (see FIG. 2), as shown in Figures 3 and 4, before causing the cameras 52 and 53 to capture an image of the kerf. Then, the state of the kerf is checked based on the captured image.

[0063] Since the kerf check is performed based on the image of the area where the TEG 66 is not present, the TEG 66 is not peeled off from the wafer 60 by the process of forming the full-cut groove 67 or the half-cut groove 68, and the kerf check can be performed.

[0064] Furthermore, since an area where no TEG 66 is present is automatically selected based on the position coordinates of the TEG 66 stored in the TEG position coordinate storage step, and an image for the kerf check is taken, the operator does not need to take the time to select and register an area for the kerf check in advance. Therefore, the kerf check of the wafer 60 on which the TEG 66 is placed on the street 63 can be easily and efficiently performed.

[0065] 3 and 4 show the formation of a kerf and the kerf check on one street 63, but it is possible to perform the formation of a kerf and the kerf check in a similar manner on other streets 63. If the arrangement of the TEG 66 (position coordinates of the TEG 66 in the X-axis direction) is different among the multiple streets 63 that are the subject of the kerf check, the position of the kerf check in the longitudinal direction of each street 63 may be different.

[0066] When performing a kerf check on a plurality of streets 63, the TEG position coordinate storage step and the kerf formation step may be repeated for each street 63. Alternatively, before a kerf is formed in the wafer 60 (FIG. 2), the TEG position coordinate storage step may be performed collectively for a plurality of streets 63 to be machined, and the kerf formation step may be performed after obtaining information on the position coordinates of the TEGs 66 on these plurality of streets 63. By obtaining the position coordinates of the TEGs 66 on the plurality of streets 63 in advance, the kerf formation step allows the plurality of streets 63 to be machined continuously without interruption for obtaining the position coordinates of the TEGs 66.

[0067] In addition, when only specific streets 63 among a plurality of streets 63 are to be subjected to kerf check, the time required for the TEG position coordinate storage step can be saved by selecting only the streets 63 for which the kerf check is to be performed in the street storage step and then performing the TEG position coordinate storage step (in other words, the TEG position coordinate storage step is not performed for the streets 63 for which the kerf check is not to be performed).

[0068] 5 shows a case where a step-cut groove 69 is formed along a street 63 as an example of forming a kerf in a wafer 60. As shown in Fig. 5, the step-cut groove 69 is a machined groove composed of a first kerf 70 with a bottom formed from the surface (upper surface) of the wafer 60 to a predetermined depth, and a second kerf 71 that is narrower than the first kerf 70 and cuts from the bottom surface of the first kerf 70 toward the lower surface of the wafer 60.

[0069] 5 is greater in width (thickness) in the Y-axis direction than in width (thickness) of the second cutting blade 14. A first kerf 70 is first formed in the street 63 using the wider first cutting blade 13, and then a second kerf 71 is formed on the bottom surface of the first kerf 70 using the narrower second cutting blade 14, thereby completing the step-cut groove 69.

[0070] In the case of the step-cut groove 69, the second kerf 71 serves as the reference for hairline alignment in the kerf check. However, with the second kerf 71 formed on the bottom surface of the first kerf 70, the edges of the kerf cannot be accurately recognized by imaging from the front surface side (above) of the wafer 60, and therefore hairline alignment cannot be performed. In other words, after the second kerf 71 is formed on the bottom surface of the first kerf 70 and the step-cut groove 69 is completed, a kerf check for hairline alignment cannot be performed. Therefore, a kerf for kerf check (hairline alignment) is formed on the front surface of the wafer 60 by the second cutting blade 14 used to form the second kerf 71, separate from the step-cut groove 69.

[0071] In this case, a kerf for kerf check is formed in an area on the surface of the wafer 60 where the first kerf 70 is not formed and where there is no TEG 66. Naturally, a kerf cannot be formed in an area where the chip 64 is present. Therefore, the kerf for kerf check is formed in the outer peripheral area 65 of the wafer 60 where the chip 64 is not formed so as not to overlap with the first kerf 70 and the TEG 66.

[0072] 6 and 7 show a form of kerf checking in which a kerf 72 for kerf checking is formed on the surface of the outer peripheral region 65 of the wafer 60 at a position other than the street 63. Each step of forming such a kerf 72 and performing a kerf check will be described.

[0073] [Memory process] First, a storage step is performed under the control of the storage unit 81 of the control unit 80. In the storage step, the camera 53 provided in the second processing unit 12 captures an image of the wafer 60, and based on the captured image, areas where the TEG 66 is not present on the street 63 are found, and the areas where the TEG 66 is not present are stored in memory. For example, the position coordinates of the TEG 66 are detected, and the areas other than the position coordinates of the TEG 66 are stored as areas where the TEG 66 is not present.

[0074] [Kerf forming process] Next, a kerf forming step is performed under the control of a kerf forming control unit 82 of the control unit 80. The kerf forming control unit 82 causes the second cutting blade 14 of the second processing unit 12 to form a kerf 72 in an area on the surface of the wafer 60 where the first kerf 70 is not formed and where the TEG 66 stored in the storage step is not present. Note that the control program is set so that the device area where each chip 64 is arranged is excluded in advance from the target area for forming the kerf 72.

[0075] The kerf formation control unit 82 selects an area other than the streets 63 as the position where the kerf 72 is to be formed (an area where the first kerf 70 and the TEG 66 are not present). In the example of FIG. 6, the outer peripheral area 65 on the -X direction side is selected as the position where the kerf 72 is to be formed, and further, a position within the outer peripheral area 65 between the streets 63 spaced apart in the Y axis direction is selected. The length of the kerf 72 in the X axis direction is set so that it does not reach the chip 64 located inside the outer peripheral area 65 (towards the center of the wafer 60).

[0076] Since the first kerf 70 is formed on the street 63, by selecting an area that is not on the street 63, the kerf 72 can be formed on the surface of the wafer 60 instead of at the bottom of the first kerf 70. Furthermore, by referring to the information stored in the storage process, the kerf 72 can be formed at a position that avoids the TEG 66.

[0077] 2, TEGs 66 are arranged in the outer peripheral region 65 on the -Y direction side and the outer peripheral region 65 on the +Y direction side. Therefore, unlike the example in FIG. 6, when forming check kerfs in the outer peripheral region 65 on the -Y direction side or the outer peripheral region 65 on the +Y direction side, it is necessary to select an area where these TEGs 66 are not present and form the kerfs. By referring to the information stored in the storage process, check kerfs can be formed in positions that avoid the TEGs 66, even in the outer peripheral region 65 on the -Y direction side or the outer peripheral region 65 on the +Y direction side.

[0078] When the above settings for the kerf 72 are completed, the kerf formation control unit 82 controls the Y-axis movement mechanism 33 to adjust the position of the second processing unit 12 in the Y-axis direction, and positions the second cutting blade 14 at the previously set position in the Y-axis direction (a position between the streets 63 spaced apart in the Y-axis direction). Also, the table feed mechanism 23 controls the table feed mechanism 23 to set the position of the chuck table 20 in the X-axis direction so that the second cutting blade 14 is positioned on the -X-direction side of the wafer 60.

[0079] Then, the spindle motor 18 is driven to rotate the second cutting blade 14, the Z-axis movement mechanism 34 is operated to lower the second cutting blade 14 in the -Z direction to a predetermined cutting depth, and the table feed mechanism 23 is used to move the chuck table 20 in the -X direction. When the processing feed amount by the table feed mechanism 23 reaches the previously set length of the kerf 72, the processing feed operation in the X-axis direction is stopped. As a result of the above operations, a kerf 72 of a predetermined length extending in the X-axis direction is formed in a portion of the surface of the outer peripheral region 65 on the -X direction side of the wafer 60 that is not a street 63, as shown in FIG.

[0080] 6 and 7, as the second cutting blade 14 forms a kerf 72 on the surface of the outer peripheral region 65 on the -X direction side, the first cutting blade 13 forms a part of the first kerf 70 in the outer peripheral region 65 on the -X direction side. Note that when forming the kerf 72, the first cutting blade 13 may be retracted above the wafer 60 so that the first cutting blade 13 does not form the first kerf 70.

[0081] Once the formation of the kerf 72 is complete, the kerf formation control unit 82 operates the Z-axis movement mechanism 34 to raise the second cutting blade 14 in the +Z direction, and separates the second cutting blade 14 from the wafer 60. Once the retraction of the second cutting blade 14 is complete, the process proceeds to the kerf check step.

[0082] [Kerf check process] The kerf check process is executed under the control of the kerf check control unit 83 of the control unit 80. As shown in Fig. 7, in the kerf check process, the camera 53 is positioned above the kerf 72 to capture an image of the kerf 72. The state of chipping in the kerf 72, etc. is checked based on the captured image.

[0083] 8 and 9 show a form of kerf checking in which a kerf 73 for kerf checking is formed on the street 63 on the surface of the outer peripheral region 65 of the wafer 60. The formation of such a kerf 73 and the kerf check are performed through a storage step, a kerf forming step, and a kerf check step, similar to the case of the kerf 72 described above. The storage step is the same as the case of the kerf 72, so a description thereof will be omitted.

[0084] [Kerf forming process] The kerf forming step is performed under the control of the kerf forming control unit 82 of the control unit 80. The kerf forming control unit 82 causes the second cutting blade 14 of the second processing unit 12 to form a kerf 73 in an area on the surface of the wafer 60 where the first kerf 70 is not formed and where the TEG 66 stored in the storage step is not present.

[0085] The kerf formation control unit 82 selects a street 63 where the first kerf 70 has not yet been formed as the position where the kerf 73 is to be formed (a region where there is no first kerf 70 or TEG 66), and further sets the region of the street 63 where there is no TEG 66 stored in the storage step as the formation range of the kerf 73. In the example of FIG. 8 , a street 63 where the first kerf 70 has not yet been formed in the outer circumferential region 65 on the −X direction side is selected as the position where the kerf 73 is to be formed. The length of the kerf 73 in the X-axis direction is set so that the kerf 73 does not reach the TEG 66 arranged on the street 63.

[0086] By selecting a street 63 where the first kerf 70 has not yet been formed, the kerf 73 can be formed on the surface of the wafer 60, not at the bottom of the first kerf 70. Furthermore, by referring to the information stored in the storage step, the kerf 73 can be formed at a position that avoids the TEG 66.

[0087] When the above settings related to the kerf 73 are completed, the kerf formation control unit 82 controls the Y-axis movement mechanism 33 to adjust the position of the second processing unit 12 in the Y-axis direction so that the second cutting blade 14 is positioned on an extension of the selected street 63 (a street 63 on which the first kerf 70 has not yet been formed). Also, the table feed mechanism 23 controls the table feed mechanism 23 to set the position of the chuck table 20 in the X-axis direction so that the second cutting blade 14 is positioned on the -X direction side of the wafer 60.

[0088] Then, the spindle motor 18 is driven to rotate the second cutting blade 14, the Z-axis movement mechanism 34 is operated to lower the second cutting blade 14 in the -Z direction to a predetermined cutting depth, and the table feed mechanism 23 is used to move the chuck table 20 in the -X direction. When the processing feed amount by the table feed mechanism 23 reaches the previously set length of the kerf 73, the processing feed operation in the X-axis direction is stopped. As a result of the above operations, a kerf 73 of a predetermined length extending in the X-axis direction is formed on the surface of the outer peripheral region 65 on the -X direction side of the wafer 60, in a portion above the street 63.

[0089] 8, when the second cutting blade 14 forms the kerf 73 in the outer peripheral region 65, the first cutting blade 13 is retracted above the wafer 60. Therefore, when the kerf 73 is formed, the first cutting blade 13 does not form the first kerf 70.

[0090] When the formation of the kerf 73 is complete, the kerf formation control unit 82 operates the Z-axis movement mechanism 34 to raise the second cutting blade 14 in the +Z direction, and separates the second cutting blade 14 from the wafer 60. When the retraction of the second cutting blade 14 is complete, a kerf check process is performed.

[0091] [Kerf check process] The kerf check process is executed under the control of the kerf check control unit 83 of the control unit 80. As shown in Fig. 9, in the kerf check process, the camera 53 is positioned above the kerf 73 to capture an image of the kerf 73. The state of chipping in the kerf 73, etc. is checked based on the captured image.

[0092] As described above, the kerf 72 in the embodiment of FIGS. 6 and 7 and the kerf 73 in the embodiment of FIGS. 8 and 9 are both formed in areas on the surface of the wafer 60 where the first kerf 70 is not formed. Therefore, the kerf 72 and the kerf 73 can be recognized by imaging with the camera 53, and hairline alignment for the kerf 72 and the kerf 73 can be performed without any problems.

[0093] Furthermore, since areas on the surface of the wafer 60 where the TEG 66 is not present are detected and stored in advance, and the kerf formation control unit 82 sets the formation positions of the kerfs 72 and 73 so as not to include the position of the TEG 66, the operator does not need to take the time to pre-select and register an area for kerf check to prevent check errors caused by the TEG 66. Even if the TEG 66 peels off from the wafer 60 in a location other than the kerfs 72 and 73, a highly accurate kerf check can be performed in the kerfs 72 and 73 without being affected by the peeling of the TEG 66. Furthermore, since the second cutting blade 14 does not cut the TEG 66 when forming the kerfs 72 and 73, abnormal wear of the second cutting blade 14, which is thinner than the first cutting blade 13, can be prevented.

[0094] When forming check kerfs such as the above-mentioned kerf 72 and kerf 73, the kerf may be formed by a so-called chopper cut in the kerf forming process, in which the wafer 60 is cut only by the second cutting blade 14 in the Z-axis direction, without performing a processing feed operation in the X-axis direction (movement of the chuck table 20 that holds the wafer 60).

[0095] As described above, according to the kerf check method and processing apparatus of each of the above-described embodiments, a camera captures an image of a wafer to acquire TEG position information (such as TEG position coordinates and information on areas where a TEG is not present), and then the kerf is automatically checked in areas where a TEG is not present. This eliminates the need for an operator to pre-register areas on the wafer where a TEG is not present, and enables kerf checks that are free of the effects of TEG peeling. In other words, kerf checks of wafers with TEGs arranged on the streets can be performed easily and with high accuracy. As a result, the processing efficiency of the wafer 60 can be improved. Furthermore, the type of kerf is not limited, and the method can be applied to check kerfs of various types, such as full-cut grooves, half-cut grooves, and step-cut grooves.

[0096] The kerf check method and processing apparatus of each of the above embodiments acquires TEG position information using a camera for capturing an image of the wafer during kerf check and alignment, and therefore can achieve kerf check that is not affected by TEG peeling with a simple configuration without adding any dedicated sensors for detecting the TEG position. Therefore, it can be introduced at low cost while utilizing the configuration of existing processing apparatus.

[0097] As mentioned above, the method for forming a kerf in a wafer is not limited to cutting using a cutting blade as in the above embodiment, but may be laser processing using irradiation of a laser beam, etc. When forming a kerf by laser processing, a processing device equipped with a laser beam irradiation unit that emits a processing laser beam is used instead of the first processing unit 11 and the second processing unit 12 in the above embodiment.

[0098] The embodiments of the present invention are not limited to the above-described embodiments and modifications, and may be variously changed, substituted, or modified without departing from the spirit of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial Applicability]

[0099] As described above, according to the present invention, the wafer is imaged with a camera and a location where there is no TEG is automatically selected for kerf checking, so that highly accurate kerf checking can be easily achieved without much effort, and the wafer processing efficiency can be improved. [Explanation of symbols]

[0100] 10: Processing equipment 11: First processing unit 12: Second processing unit 13: First cutting blade 14: Second cutting blade 20: Chuck table 21: Holding surface 23: Table feed mechanism 31:Y-axis movement mechanism 32:Z-axis movement mechanism 33:Y-axis movement mechanism 34:Z-axis movement mechanism 52: Camera 53: Camera 60: Wafer 63: Street 64: Chip 65: Outer area 67: Full cut groove (kerf) 68: Half cut groove (kerf) 69: Step cut groove (kerf) 70: First calf 71: Second calf 72: Calf 73: Calf 80: Control unit 81: Storage section 82: Kerf forming control unit 83: Kerf check control section 84: Street Memory Section 85 :TEG position coordinate storage section

Claims

1. A kerf check method for checking a kerf formed by a processing unit on a wafer having a TEG arranged on a street, the method comprising: a street storage step of imaging the wafer with a camera, determining and storing the streets along which the processing unit forms the kerf; a TEG position coordinate storage step of capturing an image of the street stored in the street storage step with the camera to acquire and store position coordinates of a TEG; a kerf forming step of forming a kerf on the street stored in the street storing step by the processing unit; a kerf check step of performing a kerf check in a place where the TEG is not present in the kerf using the position coordinates of the TEG; A kerf check method comprising:

2. A wafer processing method in which a first kerf with a bottom is formed on a wafer having a TEG arranged on a street by a first processing unit, and a second kerf is formed in the first kerf by a second processing unit, comprising the steps of: a storage step of capturing an image of the wafer with a camera to find areas on the street where the TEG is absent, and storing the areas where the TEG is absent; a kerf forming step of forming a kerf on the surface of the wafer by the second processing unit in the region where the first kerf is not formed and the TEG stored in the storing step is not present; a kerf check step of checking the kerf; A kerf check method comprising:

3. A processing apparatus including a chuck table that holds a wafer with a TEG arranged on a street, a processing unit that forms a kerf on the wafer, and a camera that takes an image of the wafer, a street storage unit that images the wafer with the camera, performs pattern matching with alignment marks formed on the wafer, and determines and stores streets to be processed; a TEG position coordinate storage unit that captures an image of the TEG on the street with the camera, acquires and stores position coordinates of the TEG; a kerf forming control unit for forming a kerf in the street by the processing unit; a kerf check control unit that takes an image of the kerf with the camera and checks the kerf at a location where the TEG is not present; A processing device comprising:

4. A processing apparatus including: a chuck table that holds a wafer having a TEG arranged on a street; a first processing unit that forms a first kerf in the wafer; a second processing unit that forms a second kerf in the wafer; and a camera that takes an image of the wafer, a storage unit that captures an image of the wafer with the camera and stores an area where no TEG is present; a kerf formation control unit that forms a kerf on the surface of the wafer by the second processing unit in the region where the first kerf is not formed and the TEG stored in the memory unit is not present; a kerf check control unit that performs a kerf check on the kerf; A processing device comprising:

Images