Methods for determining cutting devices and cutting devices

Abstract

A method for determining the suitability of a cutting apparatus and a cutting apparatus. This determination method utilizes a cutting apparatus to determine whether the start of cutting is appropriate. The cutting apparatus includes: a holding stage that holds a wafer and allows it to rotate freely; an imaging unit that images the wafer; a cutting unit that cuts the wafer; a moving mechanism that moves the cutting unit and the holding stage relative to each other in the processing feed direction and the indexing feed direction; and a controller that controls the imaging unit, the cutting unit, and the moving mechanism. The determination method includes the following steps: an alignment step, in which a predetermined cutting line parallel to the processing feed direction is set based on the image captured, and the cutting unit and the predetermined cutting line are aligned; a determination step, after the alignment step, while moving the holding stage holding the wafer relative to the imaging unit in the processing feed direction, the imaging unit captures an image of the front side of the wafer to form a determination image, and the appropriateness of the start of cutting is determined based on the image captured.

Description

Technical Field

[0001] The present invention relates to a dicing apparatus for monolithically processing a plate-shaped workpiece such as a semiconductor wafer into a chip, and more specifically, to a determination method for determining whether a predetermined dicing line has been correctly set. Background Technology

[0002] In the past, in the semiconductor device manufacturing process, multiple devices were formed on a semiconductor wafer, which was then cut (divided) into individual semiconductor device chips. In this cutting process, cutting is performed along predetermined cutting lines (spacers) set on the semiconductor wafer, and cutting equipment such as cutting devices or laser processing equipment is widely used.

[0003] The cutting apparatus has a cutting unit containing a high-speed rotating cutting tool, which performs cutting operations to form a cutting groove along a predetermined cutting line. The laser processing apparatus has a cutting unit with a laser oscillator that generates a laser beam and a focusing lens that focuses the laser beam onto a semiconductor wafer. This laser processing apparatus performs laser processing such as forming a laser processing groove along a predetermined cutting line or forming a modified layer inside the semiconductor wafer.

[0004] When processing using these cutting devices, the characteristic key patterns of the devices present on the semiconductor wafer being processed are pre-registered with the cutting device as target patterns, and the processing conditions are also registered with the cutting device. During cutting, the semiconductor wafer is photographed using an imaging unit provided by the cutting device, and the key patterns contained in the photographed image are matched with the pre-registered target patterns to determine the predetermined cutting line that becomes the cutting processing position. Next, so-called automatic alignment is performed to adjust the position of the cutting unit and the semiconductor wafer so that the predetermined cutting line is aligned with the processing point. This automatic alignment is performed automatically by the control device of the cutting device.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-050258

[0006] However, due to factors such as the type of wafer, pattern precision, dirt adhesion, and localized surface damage, automatic alignment may not be possible. In such cases, manual alignment is performed by the operator to set the predetermined cutting lines.

[0007] Specifically, first, an image is taken of one end of the wafer, and the operator selects the edge of the spacer channel between devices (e.g., the upper edge, or a pattern on the device) that appears in the captured image. Next, through automatic control of the device, the holding stage holding the wafer is moved a predetermined distance along the X-axis, and an image is taken of the other end of the wafer, with the operator selecting the edge of the spacer channel that appears in the captured image. Then, through automatic control of the device, the holding stage is rotated so that the imaginary line connecting the two points specified by the operator is aligned with θ, which is parallel to the X-axis.

[0008] After aligning the spacer with the X-axis (machining feed direction) using the θ alignment described above, the operator selects any one of the multiple spacers and specifies the center position of the selected spacer. This specified center position becomes the predetermined cutting line for the cutting tool. The operator then selects the spacer initially intended for machining as the "machining start predetermined line" and begins machining from this line.

[0009] In manual alignment as described above, the cutting pre-line may sometimes be incorrectly set due to the operator's skill level. For example, if the direction of the spacer track on the wafer holding the worktable is not parallel to the X-axis direction (processing feed direction), other spacers may sometimes be reflected in the image taken at the separated position. Furthermore, when connecting two points of other spacers, an imaginary line is set across the device, and θ alignment and the cutting pre-line are set based on this imaginary line.

[0010] Furthermore, during automatic alignment, for example, when pattern matching is performed on a pattern that is different from the target pattern, or when the wafer is set in a state of angular offset and a target pattern corresponding to other spacing channels is detected, incorrect cutting predetermined lines may also be detected. Summary of the Invention

[0011] In view of the above, the present invention proposes a new technique to prevent cutting from starting directly when the predetermined cutting line is incorrectly set.

[0012] The problem to be solved by the present invention is as described above, and the means used to solve the problem will be described below.

[0013] According to one aspect of the present invention, a method for determining whether a cutting device is appropriate is provided, the cutting device comprising: a holding table that holds a workpiece for rotation; an imaging unit that images the workpiece held by the holding table; a cutting unit that cuts the workpiece held by the holding table; a moving mechanism that moves the cutting unit and the holding table relative to each other in a processing feed direction and in an indexing feed direction perpendicular to the processing feed direction; and a controller that controls at least the imaging unit, the cutting unit, and the moving mechanism, wherein the method for determining whether a cutting device is appropriate comprises the following steps: an alignment step in which a predetermined cutting line parallel to the processing feed direction is set based on the image captured by the imaging unit, and the cutting unit and the predetermined cutting line are aligned; and a determination step in which, after the alignment step, the controller controls the moving mechanism and the imaging unit, while moving the holding table holding the workpiece relative to the imaging unit in the processing feed direction, and while the imaging unit captures an image of the front of the workpiece to form a determination image, and determines whether a cutting start is appropriate based on the image.

[0014] In addition, according to one aspect of the present invention, the cutting device further includes a warning sending unit for sending a warning, and the determination method of the cutting device includes the following warning sending step: if the determination step determines that it is inappropriate, the controller sends a warning using the warning sending unit.

[0015] In addition, according to one aspect of the present invention, the determination method of the cutting device has the following processing steps: when the determination step determines that the cutting is appropriate to start, the holding table is moved relative to the cutting unit in the processing feed direction to perform cutting processing on the predetermined cutting line.

[0016] In addition, according to one aspect of the present invention, a cutting apparatus is provided, comprising: a holding table that holds a workpiece for rotation; an imaging unit that images the workpiece held by the holding table; a cutting unit that cuts the workpiece held by the holding table; a moving mechanism that moves the cutting unit and the holding table relative to each other in a processing feed direction and in an indexing feed direction perpendicular to the processing feed direction; and a controller that controls at least the imaging unit, the cutting unit, and the moving mechanism, wherein the cutting apparatus is capable of performing the following steps: an alignment step in which a predetermined cutting line parallel to the processing feed direction is set based on the image captured by the imaging unit, and the cutting unit and the predetermined cutting line are aligned; and a determination step in which, after the alignment step, the controller controls the moving mechanism and the imaging unit to move the holding table holding the workpiece relative to the imaging unit in the processing feed direction, while the imaging unit captures an image of the front of the workpiece to form a determination image, and determines whether the cutting start is appropriate based on the image.

[0017] According to one aspect of the present invention, if it is determined that the cutting start is inappropriate, it is possible to detect that the cutting predetermined line registered by the operator's manual operation is inappropriate, and by preventing the cutting from starting, it is possible to prevent adverse situations such as damage to parts of the device caused by processing.

[0018] In addition, according to one aspect of the present invention, by issuing a warning, the operator can identify the occurrence of an anomaly.

[0019] Furthermore, according to one aspect of the invention, processing is carried out only when it is determined that cutting should begin appropriately, thus preventing cutting from starting if the predetermined cutting line registered through manual operation by the operator is inappropriate. Attached Figure Description

[0020] Figure 1 This is a perspective view showing a structural example of a laser processing apparatus as a cutting device.

[0021] Figure 2 This is a diagram showing an example of a wafer as the workpiece.

[0022] Figure 3 This is a diagram illustrating alignment.

[0023] Figure 4 This diagram illustrates the situation where there is an angular offset between the machining feed direction and the predetermined cutting line.

[0024] Figure 5 This is a flowchart illustrating the process of each step in Embodiment 1.

[0025] Figure 6 (A) is a diagram showing the setting of the predetermined cutting line extending along the first direction. Figure 6 (B) is a diagram showing the setting of the predetermined cutting line extending along the second direction. Figure 6 (C) is a diagram illustrating the situation when the alignment step is completed. Figure 6 (D) is a diagram illustrating the situation during the decision-making step.

[0026] Figure 7 Figure (A) illustrates the acquisition of the captured image in the determination step. Figure 7 (B) is a diagram illustrating the image taken along the shooting line for determining whether the image was taken.

[0027] Figure 8 (A) is a diagram illustrating the decision based on the decision line. Figure 8 (B) is a diagram illustrating the case where the direction of the line used is consistent with the direction of the machining feed.

[0028] Figure 9 (A) is a diagram showing the situation where the thin line and the judgment line are offset. Figure 9 (B) is a diagram showing the case where the thin line and the judgment line are consistent. Figure 9 (C) is a diagram illustrating the situation where a cutting groove is reflected in the captured image.

[0029] Figure 10 This is a diagram illustrating the processing steps.

[0030] Figure 11 This is a flowchart illustrating the steps of Embodiment 2.

[0031] Label Explanation

[0032] 2: Laser processing device; 10: Holding table; 10a: Holding surface; 11: Wafer; 12: Laser beam irradiation unit; 12a: Processing head; 13: Imaging unit; 15: Belt; 17: Frame; 19: Wafer unit; 100: Controller; 200: Monitor; 201: Speaker; 202: Warning light; D: Device; F1: First direction; F2: Second direction; G1: Image captured; G2: Image captured; Ga: Image captured; Gb: Image captured; H: Fine line; K: Imaginary line; Lk: Reference distance; Lm: Reference distance; Ln: Indexing distance; M: Spacing track; M1: Spacing track; M2: Spacing track; Pk: Key pattern; Pt: Target pattern; L: Cutting pre-line; L2: Cutting pre-line; L3: Imaging line; L4: Judgment line; L5: Judgment line; V: Cutting groove. Detailed Implementation

[0033] Hereinafter, an embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a perspective view showing a structural example of a laser processing apparatus 2 as a cutting device. Furthermore, in the following description, a laser processing apparatus having a laser beam irradiation unit is used as an example of a cutting device. However, a cutting device may also be a cutting device that, instead of having a laser beam irradiation unit, has a cutting unit comprising a high-speed rotating cutting tool and a spindle that rotates the cutting tool.

[0034] like Figure 1 As shown, the laser processing apparatus 2 has a base 4 that supports each component. The base 4 includes a cuboid base 6 and a wall 8 extending upward from the rear end of the base 6. A holding stage 10 is disposed on the upper surface of the base 6, which attracts and holds the wafer (workpiece) 11 through a belt 15. The holding stage 10 moves in the X and Y axis directions by a moving mechanism consisting of a Y-axis moving mechanism 16 and an X-axis moving mechanism 26.

[0035] Below the holding table 10, there is a Y-axis moving mechanism 16 that moves the holding table 10 along the Y-axis direction (indexing feed direction). The Y-axis moving mechanism 16 has a pair of Y-axis guide rails 18 fixed to the upper surface of the base 6 and parallel to the Y-axis direction.

[0036] A Y-axis movable worktable 20 is slidably mounted on the Y-axis guide rail 18. A nut portion (not shown) is provided on the back side (lower surface side) of the Y-axis movable worktable 20, and a Y-axis ball screw 22 parallel to the Y-axis guide rail 18 is rotatably coupled to the nut portion.

[0037] A Y-axis pulse motor 24 is connected to one end of the Y-axis ball screw 22. When the Y-axis ball screw 22 is rotated by the Y-axis pulse motor 24, the Y-axis moving table 20 moves along the Y-axis guide rail 18 in the Y-axis direction.

[0038] An X-axis moving mechanism 26 is provided on the front side (upper surface side) of the Y-axis moving table 20 to move the table 10 in the X-axis direction (machining feed direction) perpendicular to the Y-axis direction. The X-axis moving mechanism 26 has a pair of X-axis guide rails 28 fixed to the upper surface of the Y-axis moving table 20 and parallel to the X-axis direction.

[0039] An X-axis movable worktable 30 is slidably mounted on the X-axis guide rail 28. A nut portion (not shown) is provided on the back side (lower surface side) of the X-axis movable worktable 30, and an X-axis ball screw 32 parallel to the X-axis guide rail 28 is rotatably attached to the nut portion.

[0040] An X-axis pulse motor 34 is connected to one end of the X-axis ball screw 32. When the X-axis ball screw 32 is rotated by the X-axis pulse motor 34, the X-axis moving table 30 moves along the X-axis guide rail 28 in the X-axis direction.

[0041] A support stage 36 is provided on the front side (upper surface side) of the X-axis moving stage 30. A holding stage 10 is arranged on the upper part of the support stage 36. The holding stage 10 is connected to a rotary drive source (not shown) located below and rotates about the Z-axis. Four clamps 38 are provided around the holding stage 10, which clamp and fix the annular frame 17 supporting the wafer 11 from four directions.

[0042] The front side of the holding stage 10 is configured as a holding surface 10a for attracting and holding the wafer 11 of the wafer unit 19. The negative pressure of the attraction source (not shown) acts on the holding surface 10a through a flow path (not shown) formed inside the holding stage 10, generating an attraction force to attract the belt 15.

[0043] A support arm 40 extending forward is provided on the upper front surface of the wall portion 8, and a processing head 12a of a laser beam irradiation unit 12 is provided at the front end of the support arm 40. The laser beam irradiation unit 12 is configured to have a laser oscillator (not shown), and the processing head 12a is configured to have a focusing lens (not shown) that converges the laser beam emitted from the laser oscillator onto the wafer 11 held by the holding stage 10.

[0044] In the laser beam irradiation unit 12, an imaging unit 13 is provided on the side of the processing head 12a. This imaging unit 13 captures images of the pre-cut lines and other features on the front side of the wafer 11. The captured images are appropriately displayed on the monitor 200 via the controller 100.

[0045] The monitor 200 consists of a touch panel, configured to allow for user input. Alternatively, it can be configured to have the input device for user input separate from the monitor 200.

[0046] During laser processing, the holding table 10 is positioned below the processing head 12a of the laser beam irradiation unit 12 by fully automatic control based on the controller 100 or manual control based on the operator's operation. After proper alignment based on the image captured by the imaging unit 13, the laser beam is irradiated from the processing head 12a, and the holding table 10 is fed for processing, thereby performing laser processing.

[0047] On the upper front surface of the wall portion 8, a conveying device 60 is provided on the side of the support arm 40 for conveying the wafer unit 19 on the holding table 10 to the rotary table 52 of the cleaning device 50.

[0048] The conveying device 60 is configured to include: a holding arm 61 having a plurality of suction portions 61a for attracting and holding the upper surface of the frame 17 of the wafer unit 19; a lifting portion 62 for lifting and lowering the holding arm; a horizontal moving portion 63 connected to the lifting portion 62 for moving horizontally in the X-axis direction; and an X-axis moving mechanism 64 for moving the horizontal moving portion 63.

[0049] The X-axis direction moving mechanism 64 is configured to include: a pair of X-axis guide rails 64a, which are arranged horizontally on the front surface of the wall portion 8; an X-axis ball screw 65, which is disposed between the X-axis guide rails 64a; and an X-axis pulse motor 66, which is disposed at one end of the X-axis ball screw 65.

[0050] The X-axis ball screw 65 is inserted through a nut (not shown) provided on the horizontal moving part 63. When the X-axis ball screw 65 is rotated by the X-axis pulse motor 66, the horizontal moving part 63 moves along the X-axis guide rail 64a in the X-axis direction, and the holding arm 61 also moves in the X-axis direction.

[0051] Figure 2 An example of a wafer 11 as a workpiece is shown. A metal ring-shaped frame 17 is attached to the tape 15 in such a way that the wafer 11 is surrounded and attached to the tape 15, forming a wafer unit 19 in which the wafer 11, tape 15 and frame 17 are integrated.

[0052] On the wafer 11, there are spacer channels S extending along mutually perpendicular first directions F1 and second directions F2 and arranged in a grid pattern, and a device D is formed in the region divided by each spacer channel S.

[0053] Through automatic or manual alignment as described later, a predetermined cutting line is set in the spacer channel, laser processing is performed along the predetermined cutting line L, and then dicing is performed to monolithically form a device chip. Furthermore, in this specification, the term "setting the predetermined cutting line" includes either the detection of the predetermined cutting line based on automatic alignment or the setting of the predetermined cutting line based on manual alignment.

[0054] like Figure 2 and Figure 3 As shown, there are various patterns on the wafer that constitute each device D. Before performing the cutting process, the operator selects a characteristic key pattern Pk on the wafer and registers the key pattern Pk as the target pattern Pt in the controller 100.

[0055] Assuming that the key pattern Pk exists in the same position on each device D, the imaginary line K formed by connecting the key patterns Pk of the devices D arranged in the same column is parallel to the predetermined cutting line L.

[0056] When registering the target pattern Pt, the reference distance Lm from the key pattern Pk to the predetermined cutting line L is also registered. Various attribute information of the wafer 11, such as the indexing distance Ln between adjacent predetermined cutting lines L and S, and the diameter of the wafer 11, are registered in the controller 100 as processing conditions before processing.

[0057] Automatic alignment is performed by referring to the target pattern Pt registered in the controller 100.

[0058] Automatic alignment is performed as follows.

[0059] The controller 100 moves the stage 10, and the imaging unit 13 captures images of multiple parts of the chip 11 (in...). Figure 3 In this example, images are taken of two locations at both ends of the wafer 11 along the X-axis, thereby detecting the predetermined cutting line L. Specifically, first, an image G1 of the first location is captured, and a key pattern Pk matching the target pattern Pt is detected from the captured image G1 by pattern matching, and the coordinate position of the key pattern Pk is detected. Next, the holding stage 10 is moved in the processing feed direction (X-axis direction), and an image G2 of the second location is captured, and the coordinate position of the key pattern Pk in the captured image G2 is detected similarly.

[0060] The controller 100 detects an imaginary line K formed by connecting the coordinate positions of the two detected key patterns Pk. Furthermore, it detects a predetermined cutting line L at a position offset from the imaginary line K by a reference distance Lm. Here, if the direction of the imaginary line K deviates from the machining feed direction (X-axis direction), the controller appropriately adjusts the angle at which the stage 10 rotates, and records the adjustment angle (θ alignment action).

[0061] Next, the holding stage 10 is rotated 90 degrees, and the predetermined cutting line L extending along the second direction F2 of the wafer 11 is also detected. Here, for the second direction F2, if the direction of the imaginary line deviates from the machining feed direction (X-axis direction), the angle of rotation of the holding stage 10 is also adjusted appropriately, and the adjustment angle (θ alignment action) is recorded.

[0062] Next, in order to perform laser processing on the detected cutting pre-line using the laser beam irradiation unit 12, the position of the cutting pre-line on the software is aligned with the position of the laser beam irradiation unit 12. In this way, automatic alignment is completed to align the cutting pre-line with the laser processing position.

[0063] In the processing after automatic alignment, for example, relative to the laser beam irradiation unit 12, processing begins by positioning the wafer 11 at the predetermined cutting line L2 extending along the second direction F2 on its outermost side, and a rotation feed is performed to process all predetermined cutting lines in the second direction F2. Then, similarly, the wafer is rotated 90 degrees, and processing begins from the predetermined cutting line L1 extending along the first direction F1 on the outermost side of the wafer 11, and a rotation feed is performed to process all predetermined cutting lines in the first direction F1.

[0064] Here, in Figure 3 In cases where wafer 11 is contaminated or its pattern is locally damaged, a defect occurs where the critical pattern Pk, which matches the target pattern Pt, cannot be detected, thus preventing the detection of the predetermined cutting line L. In such situations, wafer 11 processing is not initiated; instead, wafer 11 is temporarily removed and aligned manually at another time before processing is performed. Furthermore, if processing is stopped due to tool breakage, the unprocessed areas of the wafer are processed after the operator replaces the tool. During this processing, alignment based on manual alignment mode is also performed.

[0065] Manual alignment is performed as follows.

[0066] When manual alignment mode is selected and execution begins, as follows: Figure 3 As shown, the controller 100 captures an image G1 of a predetermined area on the wafer 11. The operator, for example, selects the upper edge of the spacer S appearing in the captured image G1 as a first point P1. When this first point P1 is selected, the controller 100 moves the wafer 11 (holding stage 10) a predetermined distance in the X-axis direction, which is the processing feed direction, and captures an image G2 of a second portion. The operator, for example, selects the upper edge of the spacer S appearing in the captured image G2 as a second point P2.

[0067] The controller 100 connects two points P1 and P2 selected by the operator to set an imaginary line K1. When the imaginary line K1 is not aligned with the X-axis direction, the controller 100 rotates the wafer 11 (holding stage 10) to perform θ alignment, bringing the imaginary line K1 aligned with the X-axis direction. After θ alignment, the controller 100 sets the position separated from the imaginary line K1 by a pre-registered reference distance Lk as the predetermined cutting line. Thus, the controller 100 sets the predetermined cutting line according to the operator's operation.

[0068] Here, in Figure 3 In cases where the operator's skill level is low, and the second point P2 should be selected within the captured image G2 but a different position P3 is selected instead, an imaginary line Kz that is not parallel to the interval channel S will be set, thus setting an incorrect cutting predetermined line.

[0069] In addition, such as Figure 4 As shown, when the spacer S of the wafer 11 is not parallel to the X-axis direction, which is the processing feed direction, and the wafer 11 is set at an offset angle θ, it is possible that other columns of spacer S1 and S2 may be included in each captured image G1 and G2. Moreover, when the imaginary line K2 is set based on the spacer S1 and S2 appearing in each captured image G1 and G2, the cutting predetermined line L6 will be set in the position where there would not be a spacer.

[0070] like Figure 3 and Figure 4 As shown, processing device D with an incorrect cutting pre-line can damage it. To prevent such an adverse situation, the present invention implements a cutting pre-line detection method and a determination method as follows.

[0071] The following describes the detection and determination method for the pre-cutting line of the present invention.

[0072] Example 1

[0073] Example 1 is an example of detecting and judging the predetermined cutting lines without performing manual alignment, such as detecting key patterns on unprocessed wafers. Figure 5 This is a flowchart illustrating the process of each step in the case of Example 1.

[0074] <Alignment Steps>

[0075] exist Figure 3 The alignment step is as follows: A predetermined cutting line L parallel to the machining feed direction (X-axis direction) is manually aligned, and the cutting unit (laser beam irradiation unit 12) and the predetermined cutting line are aligned (…). Figure 5 Step S1 in the process.

[0076] Specifically, such as Figure 6 As shown in (A), for the first direction F1 of wafer 11, as described above, the controller sets a predetermined cutting line L that is parallel to the processing feed direction (X-axis direction) based on two points P1 and P2 selected by the operator.

[0077] In addition, the controller aligns the position of the predetermined cutting line on the software with the position of the laser beam irradiation unit 12 so that the laser beam irradiation unit 12 can be used to perform laser processing on the predetermined cutting line.

[0078] As described above, a cutting predetermined line is set, and an alignment is performed to align the cutting predetermined line with the laser processing position.

[0079] <Judgment Steps>

[0080] like Figure 6 (D) Figure 7 (A) Figure 7 (B) and Figure 8 As shown in (A), the determination step is as follows: After the alignment step is performed, while moving the wafer 11 (holding stage 10) relative to the imaging unit 13 in the processing feed direction, the front side of the wafer 11 is photographed to form multiple determination images Ga, Gb..., and the appropriateness of cutting start is determined based on the formed images Ga, Gb... . In this embodiment, firstly, a determination step is performed on the predetermined cutting line extending along the first direction F1 ( Figure 5 Step S2 in the process.

[0081] Specifically, after moving the wafer 11 (holding stage 10) in the Y-axis direction to align the position of the imaging unit 13 in the Y-axis direction with the position of the imaging line L3, which serves as the position of the imaging images Ga, Gb... used for imaging determination, the wafer 11 (holding stage 10) is moved in the X-axis direction (processing feed direction) to obtain the imaging images Ga, Gb...

[0082] Furthermore, the position of the Y-axis direction of the imaging line L3 can be arbitrarily set by the operator, for example, as the area to be cut. Alternatively, it can be automatically set by the controller based on the attribute information of the chip 11, or it can be used as the area offset by a predetermined number of lines from the predetermined cutting line from the start of cutting. Figure 6 In example (D), an example of capturing images Ga, Gb... for determination along the shooting line L3 is shown.

[0083] In addition, such as Figure 7 As shown in (B), in the images Ga, Gb, etc. used for determination, all positions with the shooting line L3 set are captured. In addition, multiple positions can be captured at intervals, or a single position can be captured.

[0084] Based on the captured images Ga, Gb, etc., used for the above judgment, the controller determines whether the cutting start is appropriate. If the cutting start is determined to be inappropriate, it can detect that the set cutting pre-line is inappropriate, etc., and prevent the cutting from starting, thus preventing damage to parts of the device caused by processing.

[0085] As for the criteria for judgment, for example, the following can be considered: in addition to judging all the content, any one of the content can also be judged.

[0086] <Judgment Content 1>

[0087] Determine whether the set cutting line is parallel to the X-axis direction.

[0088] For example, in such Figure 4 In such a case, if the wafer 11 is tilted and incorrectly set while the cutting predetermined line is tilted, such as... Figure 8 As shown in (A), the predetermined cutting line appearing in the captured image for determination also becomes tilted.

[0089] In the implementation of this determination content 1, firstly, the controller 100 sets the determination line L4. Specifically, the controller 100 detects the edges (edges) Sf of the interval S through image processing, and connects the detected edges Sf to form the determination line L4. Alternatively, the controller 100 can detect the key pattern Pk and the target pattern Pt in each captured image through pattern matching. Figure 4 Furthermore, the decision line L4 is set by connecting the positions separated from each key pattern Pk by the reference distance Lm.

[0090] Furthermore, if the controller 100 determines that the cutting start is inappropriate if the line L4 is deviated from the machining feed direction (X-axis direction) by more than a specified angle. Figure 8 In example (A), the offset angle θ is used, therefore it is deemed inappropriate.

[0091] On the other hand, such as Figure 8 As shown in (B), if the direction of the line L4 is consistent with the machining feed direction (X-axis direction), the cutting is deemed to have started appropriately.

[0092] <Judgment Content 2>

[0093] like Figure 9 As shown in (A), it is determined whether the set cutting predetermined line is the center of the Y-axis direction of the interval channel.

[0094] In the implementation of determination content 2, the determination line L5 is set by the controller 100. Specifically, the controller detects the edges Sf of adjacent devices D in the Y direction of the spacing channel through image processing, and sets the line at the middle position of the detected edge Sf in the Y-axis direction as the determination line L5. Furthermore, it detects whether the determination line L5 is offset from the Y-axis position (processing predetermined position) of the thin line H set in the imaging unit 13.

[0095] The imaging unit 13 is composed of a microscope. A thin line H is set at the center of the image captured by the microscope, and processing is performed at the position corresponding to the Y-axis position of the thin line H. Furthermore, if the alignment steps described above are completed without any problems, processing is performed at the position corresponding to the Y-axis position of the thin line H.

[0096] Furthermore, for example, if the determination line L5 deviates from the position of the thin line H by a predetermined distance, the controller 100 determines that the cutting initiation is inappropriate. Figure 9 In example (A), the offset ΔY is above the specified distance, therefore it is deemed inappropriate.

[0097] On the other hand, such as Figure 9 As shown in (B), if the positions of the cutting line L5 and the thin line H are aligned, the cutting is deemed to have begun appropriately. Furthermore, in Figure 9 In example (B), the case where the line L5 is consistent with the thin line H is shown.

[0098] In addition, Figure 9 (A) Figure 9 In (B), a determination line L5 is set at the middle position of the adjacent device D along the Y-axis direction of the spacer S. The relative position of the determination line L5 and the thin line H is compared. However, if the device D exists only on one side of the spacer S along the Y-axis direction, the determination can also be made by detecting whether the thin line H exists at the position where the reference distance Lm is separated from multiple key patterns Pk.

[0099] <Judgment Content 3>

[0100] like Figure 9 As shown in (C), it is determined whether the predetermined cutting line has been processed.

[0101] When cutting a pre-machined line, undesirable situations can sometimes occur. For example, in a cutting device that uses a cutting tool to form a cutting groove, further machining of the previously formed cutting groove V may cause the cutting tool to break. In such cases, it is inappropriate to cut the predetermined line that appears in the captured image.

[0102] exist Figure 9 In example (C), if a cutting groove V is captured in the image used for determination, the controller 100 identifies the cutting groove V through image analysis and determines that the cutting start is inappropriate. On the other hand, if the cutting groove V is not identified, the determination is appropriate regarding determination content 3.

[0103] <Warning Steps>

[0104] The warning procedure is as follows: In the above determination steps, if it is determined that the cutting start is inappropriate, a warning is issued through the warning sending unit. Figure 5 Step S3 in the process.

[0105] Specifically, in Figure 1In the structural example shown, the controller 100 sends warnings based on display, sound, light, etc. from warning sending units such as the monitor 200, speaker 201, and warning light 202.

[0106] When this warning step is implemented, the controller 100 interrupts the cutting process. Alternatively, the warning step can be omitted, and the cutting process can be interrupted without sending a warning.

[0107] By sending warnings as described above, operators can identify abnormalities.

[0108] <Processing Steps>

[0109] The processing steps are as follows: In the above determination steps, if it is determined that the cutting should begin appropriately, such as... Figure 10 As shown, the holding table 10 is moved relative to the laser beam irradiation unit 12 (processing head 12a), which serves as the cutting unit, in the processing feed direction, and the laser beam B is irradiated to cut the predetermined cutting line. Figure 5 Step S4 in the process.

[0110] By performing the aforementioned judgments in the stage prior to the processing steps, the probability of undesirable situations occurring at the start of the cutting process can be reduced.

[0111] In addition, processing is only carried out when it is determined that the cutting should begin, which can prevent cutting from starting if the set cutting predetermined line is inappropriate.

[0112] In this processing step, such as Figure 6 As shown in (A), a predetermined cutting line extending along the first direction F1 is processed. After the processing step of the predetermined cutting line extending along the first direction F1 is completed, the wafer is rotated 90 degrees. Figure 5 In step S5), the alignment step is performed similarly for the second direction F2. Figure 5 Step S6), determination step ( Figure 5 Step S7), warning step ( Figure 5 Step S8) and processing steps ( Figure 5 Step S9 in the process.

[0113] Furthermore, during the determination step for the second direction F2, the cutting groove formed along the first direction F1 may be reflected in the image captured for determination, resulting in a misjudgment in the determination content 3 above. Therefore, it is preferable to perform image processing that masks the cutting groove in a way that does not display it in the image captured for determination.

[0114] Alternatively, after performing a determination step on the predetermined cutting line extending along the first direction F1, the wafer is rotated 90 degrees, and after performing an alignment step, a determination step, and a warning step on the predetermined cutting line extending along the second direction F2, a processing step is performed on the predetermined cutting line extending along the second direction F2. Then, the wafer is rotated 90 degrees, and a processing step is performed on the predetermined cutting line extending along the first direction F1.

[0115] Alternatively, after performing a manual alignment step on the first direction F1 of the wafer, the wafer is rotated 90 degrees to perform a manual alignment step on the second direction F2 of the wafer. Then, after performing a judgment step, a warning step, and a processing step on the second direction F2, the wafer is rotated 90 degrees to perform a judgment step, a warning step, and a processing step on the first direction F1.

[0116] In this case, during the determination step for the first direction F1, the cutting groove formed along the second direction F2 may be reflected in the image captured for determination, resulting in a misjudgment in the determination content 3. Therefore, it is preferable to perform image processing that masks the cutting groove in a way that does not display it in the image captured for determination.

[0117] Example 2

[0118] The same judgment as described above can be made when automatic alignment is performed. Figure 11 This is a flowchart illustrating the steps involved in performing Example 2.

[0119] First, similar to the alignment step described above, a predetermined cutting line parallel to the processing feed direction (X-axis direction) is set by automatic alignment, and the cutting unit (laser beam irradiation unit 12) and the predetermined cutting line are aligned.

[0120] In the first direction F1 of the wafer ( Figure 6 After the alignment step, determination step, and warning step are performed in (A), the wafer is rotated 90 degrees to align with the wafer in the second direction F2. Figure 6 Similarly, (B) performs the alignment step, the judgment step, and the warning step.

[0121] Without issuing any warnings, the processing steps are performed directly on the second direction F2, and then the wafer is rotated 90 degrees again to perform the processing steps on the first direction F1.

[0122] In addition to the above, it is also possible to perform an alignment step, a judgment step, a warning step, and a processing step based on automatic alignment on the first direction F1 of the wafer, and then rotate the wafer by 90 degrees to perform an alignment step, a judgment step, a warning step, and a processing step based on automatic alignment on the second direction F2 of the wafer.

[0123] In this case, during the determination step for the second direction F2, the cutting groove formed along the first direction F1 may be reflected in the image captured for determination, resulting in a misdetermination in the determination content 3. Therefore, it is preferable to perform image processing that masks the cutting groove in a way that does not show it in the image captured for determination.

[0124] Alternatively, after performing an alignment step based on automatic alignment on the first direction F1 of the wafer, the wafer is rotated 90 degrees to perform an alignment step based on automatic alignment on the second direction F2 of the wafer. Then, after performing a determination step, a warning step, and a processing step on the second direction F2, the wafer is rotated 90 degrees to perform a determination step, a warning step, and a processing step on the first direction F1.

[0125] In this case, during the determination step for the first direction F1, the cutting groove formed along the second direction F2 may be reflected in the image captured for determination, resulting in a misjudgment in the determination content 3. Therefore, it is preferable to perform image processing that masks the cutting groove in a way that does not display it in the image captured for determination.

Claims

1. A determination method of a cutting apparatus that determines whether or not cutting start is appropriate using a cutting apparatus having: a holding table that holds a workpiece so as to be rotatable; a photographing unit that photographs the workpiece held by the holding table; a cutting unit that cuts the workpiece held by the holding table; a moving mechanism that relatively moves the cutting unit and the holding table in a machining feed direction and relatively moves the cutting unit and the holding table in an indexing feed direction that is perpendicular to the machining feed direction; and a controller that controls at least the photographing unit, the cutting unit, and the moving mechanism, wherein the determination method of the cutting apparatus has: an alignment step of setting a cutting intended line that is parallel to the machining feed direction based on a photographed image acquired by the photographing unit and aligning the cutting unit and the cutting intended line; and a determination step of, after the alignment step is implemented, the controller controlling the moving mechanism and the photographing unit to move the holding table holding the workpiece relatively to the photographing unit in the indexing feed direction and then move the holding table relatively to the photographing unit in the machining feed direction, and forming a determination-use photographed image by photographing a front surface of the workpiece along a determination-use photographing line using the photographing unit, and determining whether or not cutting start is appropriate based on the photographed image.

2. The determination method of the cutting apparatus according to claim 1, wherein the cutting apparatus further has a warning transmitting unit that transmits a warning, and the determination method of the cutting apparatus has a warning transmitting step of, in a case where it is determined that it is not appropriate by the determination step, the controller transmitting a warning using the warning transmitting unit.

3. The determination method of the cutting apparatus according to claim 1 or 2, wherein the determination method of the cutting apparatus has a machining step of, in a case where it is determined that cutting start is appropriate by the determination step, relatively moving the holding table relatively to the cutting unit in the machining feed direction and machining the cutting intended line.

4. A cutting apparatus having: a holding table that holds a workpiece so as to be rotatable; a photographing unit that photographs the workpiece held by the holding table; a cutting unit that cuts the workpiece held by the holding table; a moving mechanism that relatively moves the cutting unit and the holding table in a machining feed direction and relatively moves the cutting unit and the holding table in an indexing feed direction that is perpendicular to the machining feed direction; and a controller that controls at least the photographing unit, the cutting unit, and the moving mechanism, wherein the cutting apparatus is capable of implementing: an alignment step of setting a cutting intended line that is parallel to the machining feed direction based on a photographed image acquired by the photographing unit and aligning the cutting unit and the cutting intended line; and a determination step of, after the alignment step is implemented, the controller controlling the moving mechanism and the photographing unit to move the holding table holding the workpiece relatively to the photographing unit in the indexing feed direction and then move the holding table relatively to the photographing unit in the machining feed direction, and forming a determination-use photographed image by photographing a front surface of the workpiece along a determination-use photographing line using the photographing unit, and determining whether or not cutting start is appropriate based on the photographed image. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The controller controls the moving mechanism and the photographing unit after the alignment step, moves the holding table holding the workpiece in the indexing feed direction with respect to the photographing unit, and then moves the holding table in the machining feed direction with respect to the photographing unit, photographs the front surface of the workpiece along a photographing line for determination to form a photographing image for determination, and determines whether the cutting start is appropriate based on the photographing image.

Images