Conveyance offset amount detection method

Abstract

The present application provides a method for detecting a conveyance offset, which easily calculates the conveyance offset of a conveyance unit. The method includes the following steps: a first coordinate storage step, in which a workpiece with a mark M is held on a first worktable and photographed by a photographing unit, and the coordinates of the mark M are stored as X1 and Y1 coordinates; a 180-degree rotation step, in which the workpiece held on the first worktable is conveyed to a second worktable by a conveyance unit and held, and the second worktable is rotated by 180 degrees; a return step, in which the workpiece held on the second worktable is conveyed to the first worktable by the conveyance unit and held; a second coordinate storage step, in which the first worktable is rotated by 180 degrees and the workpiece is photographed by the photographing unit, and the coordinates of the mark M are stored as X2 and Y2 coordinates; and a conveyance offset calculation step, in which (X2-X1) / 2 is calculated as the conveyance offset in the X-axis direction, and (Y2-Y1) / 2 is calculated as the conveyance offset in the Y-axis direction.

Description

Technical Field

[0001] This invention relates to a method for detecting conveying offset, which calculates the conveying offset of a conveying unit that conveys a workpiece from a first worktable to a second worktable. Background Technology

[0002] A wafer with multiple devices such as ICs and LSIs formed on its front side by a pre-defined dividing line is divided into individual device chips by a dicing device. The resulting device chips are then used in electronic devices such as mobile phones and personal computers.

[0003] The cutting apparatus generally includes: a chuck stage for holding a wafer; a cutting unit for cutting the wafer held by the chuck stage; an X-axis feed unit for feeding the chuck stage and the cutting unit relative to each other in the X-axis direction; a Y-axis feed unit for indexing the chuck stage and the cutting unit relative to each other in the Y-axis direction; an imaging unit for imaging the wafer held by the chuck stage to detect the area to be cut; a cleaning unit for cleaning the cut wafer; and a transport unit for transporting the wafer from the chuck stage to the cleaning unit. This cutting apparatus can cut wafers with high precision (see, for example, Patent Document 1). The cleaning unit of the cutting apparatus includes: a rotatable rotary table for holding the wafer; and a cleaning fluid spray nozzle for spraying cleaning fluid onto the wafer held by the rotary table.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2010-36275

[0005] However, if the wafer, held at the appropriate position on the chuck stage of the dicing unit, cannot be properly transferred to the appropriate position on the rotary stage of the cleaning unit via the transfer unit, the wafer may scatter from the rotary stage due to its high-speed rotation. Therefore, it is necessary to measure the direction and distance from the chuck stage to the rotary stage to fine-tune the transfer direction and distance of the transfer unit. However, this fine-tuning has the following problems: it is time-consuming and has poor productivity.

[0006] This problem occurs in various processing devices (such as laser processing devices, grinding devices, and inspection devices) that have mechanisms for transferring wafers between two or more worktables. Summary of the Invention

[0007] In view of the above facts, the objective of the present invention is to provide a method for detecting conveying offset, which can easily determine the conveying offset of a conveying unit.

[0008] According to the present invention, a method for detecting transport offset is provided to solve the above-mentioned problems. Specifically, a method for detecting transport offset is provided in which the transport offset of a transport unit is determined in a processing apparatus for processing a workpiece. The processing apparatus includes at least a rotatable first worktable, a rotatable second worktable, a transport unit for transporting a workpiece from the first worktable to the second worktable, and a photographing unit for photographing a workpiece held on the first worktable. The method includes the following steps: a first coordinate storage step, in which a marked workpiece is held on the first worktable and photographed using the photographing unit, and the coordinates of the marked workpiece are stored as X1 and Y1 coordinates; and a 180-degree rotation step. The process involves: 1) transferring the workpiece held on the first worktable to the second worktable via the transfer unit and holding it thereafter, and rotating the second worktable 180 degrees; 2) returning to the first worktable via the transfer unit and holding it thereafter; 3) storing the second coordinates by rotating the first worktable 180 degrees and taking a picture of the workpiece using the imaging unit, storing the marked coordinates as X2 and Y2 coordinates; and 4) calculating the transfer offset by using (X2-X1) / 2 as the transfer offset in the X-axis direction and (Y2-Y1) / 2 as the transfer offset in the Y-axis direction.

[0009] Preferably, (X2-X1) / 2 and (Y2-Y1) / 2 are added to the movement of the conveying unit to correct the conveying offset.

[0010] The conveying offset detection method of the present invention determines the conveying offset of a conveying unit in a processing apparatus that processes a workpiece. The processing apparatus includes at least a rotatable first worktable, a rotatable second worktable, a conveying unit for conveying a workpiece from the first worktable to the second worktable, and a photographing unit for photographing the workpiece held on the first worktable. The conveying offset detection method includes the following steps: a first coordinate storage step, in which a marked workpiece is held on the first worktable and photographed using the photographing unit, and the coordinates of the marked workpiece are stored as X1 and Y1 coordinates; and a 180-degree rotation step, in which the conveying unit conveys the workpiece held on the first worktable to the second worktable. The process involves: a first worktable and holding the workpiece, rotating the second worktable 180 degrees; a return process, where the workpiece held on the second worktable is transferred to the first worktable via the transfer unit and held there; a second coordinate storage process, where the first worktable is rotated 180 degrees, the workpiece is photographed using the imaging unit, and the marked coordinates are stored as X2 and Y2 coordinates; and a transfer offset calculation process, where (X2-X1) / 2 is used as the transfer offset in the X-axis direction and (Y2-Y1) / 2 is used as the transfer offset in the Y-axis direction. Therefore, it is not necessary to measure the direction and distance from the first worktable to the second worktable, and the transfer offset of the transfer unit can be easily calculated based on the offset of the marked coordinates. Attached Figure Description

[0011] Figure 1 This is a perspective view of a processing apparatus capable of implementing the conveying offset detection method of the present invention.

[0012] Figure 2 It is a top view of the marked workpiece.

[0013] Figure 3 yes Figure 1 A schematic top view of the first and second workbenches shown.

[0014] Figure 4 This is a schematic top view of the first and second worktables in the first coordinate storage process.

[0015] Figure 5 This is a schematic top view showing the state in which the workpiece held on the first worktable is transferred to the second worktable and held thereby via a transfer unit.

[0016] Figure 6 It shows from Figure 5 The diagram shows a schematic top view of the second worktable rotated 180 degrees.

[0017] Figure 7This is a schematic top view showing the state in which the workpiece held by the second worktable is transferred to the first worktable and held thereby via the transfer unit.

[0018] Figure 8 It shows from Figure 7 The diagram shows a schematic top view of the first worktable rotated 180 degrees.

[0019] Label Explanation

[0020] 2: Processing device; 4: First workbench; 6: Second workbench; 8: Conveying unit; 10: Imaging unit; W: Workpiece. Detailed Implementation

[0021] Hereinafter, a preferred embodiment of the conveying offset detection method of the present invention will be described with reference to the accompanying drawings.

[0022] First, the processing apparatus capable of implementing the conveying offset detection method of the present invention will be described. Figure 1 The processing apparatus 2 shown includes at least: a first worktable 4 that can rotate; a second worktable 6 that can rotate; a transfer unit 8 that transfers workpieces from the first worktable 4 to the second worktable 6; and a photographing unit 10 that photographs the workpiece held on the first worktable 4.

[0023] The circular first worktable 4 is conveyed by the X-axis transport unit (not shown) in... Figure 1 The material is conveyed along the X-axis direction indicated by the middle arrow X, and is transported via a motor (not shown) on the first worktable 4 at the center C1 (see reference). Figure 3 The X-axis conveying unit can be configured, for example, to include: a ball screw connected to the first worktable 4 and extending along the X-axis; and a motor that rotates the ball screw. Additionally, Figure 1 The Y-axis direction indicated by the middle arrow Y is perpendicular to the X-axis direction. The XY plane defined by the X-axis and Y-axis directions is actually horizontal.

[0024] like Figure 1 As shown, a porous, circular suction chuck 4a connected to a suction unit (not shown) is disposed at the upper part of the first worktable 4. Furthermore, the first worktable 4 utilizes the suction unit to generate an attractive force on the suction chuck 4a, thereby attracting a workpiece W (see reference 1) in the shape of a circular semiconductor wafer. Figure 2 The first worktable 4 attracts and holds the workpiece W during the cutting process. Additionally, the processing apparatus 2 in the illustrated embodiment is a cutting device that performs cutting operations on the workpiece W, and the first worktable 4 attracts and holds the workpiece W during the cutting operation.

[0025] The second worktable 6 in the illustrated embodiment is a rotary worktable that attracts and holds the workpiece W when cleaning a workpiece W that has been machined and has shavings attached. The circular second worktable 6 is connected by a second worktable motor (not shown) with respect to the center C2 (see reference). Figure 3 It rotates around an axis.

[0026] like Figure 1 As shown, similar to the first worktable 4, a porous, circular suction chuck 6a connected to a suction unit (not shown) is disposed at the upper part of the second worktable 6. Furthermore, in the second worktable 6, the suction unit also generates a suction force on the suction chuck 6a, thereby attracting and holding the workpiece W. Additionally, while rotating the second worktable 6 that holds the workpiece W, cleaning fluid is sprayed onto the workpiece W from a cleaning fluid spray nozzle (not shown), thereby cleaning the workpiece W.

[0027] The conveying unit 8 of the illustrated embodiment includes: the X-axis conveying unit described above, which conveys the workpiece W held by the first worktable 4 in the X-axis direction; and the Y-axis conveying unit 11, which holds and lifts the workpiece W held by the first worktable 4, and conveys it in the Y-axis direction.

[0028] The Y-axis conveying unit 11 includes: an arm 12 movable in the Y-axis direction; an arm moving unit (not shown) for moving the arm 12 in the Y-axis direction; a bracket plate 14 mounted on the lower surface of the front end of the arm 12; an H-shaped plate 16 fixed to the lower surface of the bracket plate 14; and a plurality of suction pads 18 disposed on the lower surface of the plate 16. The arm moving unit may, for example, be configured to have: a ball screw connected to the arm 12 and extending along the Y-axis direction; and an electric motor that rotates the ball screw. The bracket plate 14 is configured to extend and retract freely in the vertical direction via a suitable actuator such as a cylinder. Additionally, each suction pad 18 is connected to the suction unit (not shown).

[0029] In the transfer unit 8, after the first worktable 4 is positioned at the predetermined transfer start position using the X-axis transfer unit, the workpiece W on the first worktable 4 is attracted and held by the suction pad 18 of the Y-axis transfer unit 11, and the workpiece W is received from the first worktable 4. Furthermore, the Y-axis transfer unit 11, having received the workpiece W, moves the arm 12 and the bracket plate 14 to transfer the workpiece W from the first worktable 4 to the second worktable 6.

[0030] The imaging unit 10 captures images of the workpiece W on the first worktable 4, which is positioned at a predetermined imaging location by the X-axis conveying unit. The image data captured by the imaging unit 10 is sent to the control unit (not shown) of the processing device 2.

[0031] The computer-based control unit includes: a central processing unit (CPU) that performs calculations according to the control program; a read-only memory (ROM) that stores the control program, etc.; and a read-write random access memory (RAM) that stores the calculation results, etc. Furthermore, the control unit performs image analysis on the image data sent from the imaging unit 10, for example, acquiring the mark M formed on the workpiece W (see reference). Figure 2 The X and Y coordinates of the processing unit 2 are calculated and stored. Furthermore, the control unit controls the operation of the processing unit 2; for example, it controls the movement of the conveying unit 8 based on conditions pre-input to the control unit.

[0032] like Figure 1 As shown, the processing device 2 further includes: a cutting unit 20 that cuts the workpiece W held on the first worktable 4; a lifting and lowering box 24 that holds a box 22 containing multiple workpieces W; a transfer unit 28 that pulls out the workpiece W before processing from the box 22 and moves it to a temporary storage table 26, and moves the processed workpiece W positioned on the temporary storage table 26 into the box 22; and a moving unit 30 that moves the workpiece W before processing from the box 22 to the temporary storage table 26 to the first worktable 4.

[0033] Next, the method for detecting the conveying offset of the conveying unit 8, which is calculated in the above-mentioned processing device 2, will be described. In the illustrated embodiment, the first coordinate storage process is first performed, in which the workpiece W with the mark M is held on the first worktable 4 and photographed using the imaging unit 10, and the coordinates of the mark M are stored as X1 and Y1 coordinates.

[0034] In the first coordinate storage process, the workpiece W is first placed on the first worktable 4 with the face bearing the mark M facing upwards. Next, the first worktable 4 is moved by the X-axis transport unit to position it at a predetermined shooting position, and the shooting unit 10 takes a picture of the workpiece W held on the first worktable 4. Furthermore, the control unit performs image analysis on the image captured by the shooting unit 10, obtains the coordinates of the mark M as X1 and Y1 coordinates, and stores them (see reference). Figure 4 ).

[0035] After the first coordinate storage process is performed, a 180-degree rotation process is performed: the workpiece W held by the first worktable 4 is transferred to the second worktable 6 by the transfer unit 8 and held there, and the second worktable 6 is rotated 180 degrees.

[0036] In the 180-degree rotation process, the first worktable 4 is first moved by the X-axis conveying unit and positioned at the designated conveying start position. Once the first worktable 4 is positioned at the conveying start position, the arm 12 and the bracket plate 14 of the Y-axis conveying unit 11 are activated, causing the suction pads 18 to adhere tightly to the upper surface of the workpiece W on the first worktable 4. Next, the workpiece W is held in place by the suction pads 18, and the suction force of the first worktable 4 is released.

[0037] Next, the arm 12 and the bracket plate 14 of the Y-axis transfer unit 11 are actuated, thereby transferring the workpiece W from the first worktable 4 to the second worktable 6, so that the lower surface of the workpiece W contacts the upper surface of the second worktable 6. Then, the second worktable 6 holds the workpiece W by attraction, and the attraction force of the attraction pad 18 is released. In this way, the workpiece W is transferred from the Y-axis transfer unit 11 to the second worktable 6 (see reference). Figure 5 Furthermore, if workpiece W is transferred to the second worktable 6, the second worktable will be operated by a motor, such as... Figure 6 As shown, the second worktable 6, which holds the workpiece W by attraction, is rotated 180 degrees.

[0038] After the 180-degree rotation process, a return process is performed: the workpiece W held by the second worktable 6 is transferred to the first worktable 4 and held by the transfer unit 8.

[0039] In the return process, firstly, the suction pads 18 of the Y-axis conveying unit 11 are brought into close contact with the upper surface of the workpiece W on the second worktable 6, using the suction pads 18 to hold the workpiece W, and then the suction force of the second worktable 6 is released. Next, the arm 12 and the bracket plate 14 are moved, thereby transferring the workpiece W from the second worktable 6 to the first worktable 4, so that the lower surface of the workpiece W contacts the upper surface of the first worktable 4. Furthermore, as... Figure 7 As shown, the workpiece W is held by attraction via the first worktable 4, and the attraction force of the attraction pad 18 is released. In this way, the workpiece W returns from the second worktable 6 to the first worktable 4.

[0040] After the return process is performed, the second coordinate storage process is performed: the first worktable 4 is rotated 180 degrees, the workpiece W is photographed by the imaging unit 10, and the coordinates of the mark M are stored as X2 and Y2 coordinates.

[0041] In the second coordinate storage process, firstly as follows Figure 8As shown, the first worktable is operated by a motor, causing the first worktable 4, which holds the workpiece W, to rotate 180 degrees. Next, the first worktable 4 is moved via the X-axis conveying unit, positioning it at a predetermined shooting position. The shooting unit 10 then captures an image of the workpiece W held by the first worktable 4. Furthermore, the control unit performs image analysis on the image captured by the shooting unit 10, obtaining and storing the coordinates of marker M as X2 and Y2 coordinates (see reference). Figure 8 ).

[0042] After the second coordinate storage process is performed, a transport offset calculation process is performed: (X2-X1) / 2 is used as the transport offset in the X-axis direction, and (Y2-Y1) / 2 is used as the transport offset in the Y-axis direction. In the illustrated embodiment, the transport offset is calculated by the control unit.

[0043] In the illustrated embodiment, as described above, the workpiece W transferred from the first worktable 4 to the second worktable 6 is rotated 180 degrees within the second worktable 6, and the workpiece W transferred (returned) from the second worktable 6 to the first worktable 4 is rotated 180 degrees within the first worktable 4. Therefore, in the case of a transfer offset by the transfer unit 8, the distance between the coordinates (X1, Y1) of the mark M before transfer and the coordinates (X2, Y2) of the mark M after transfer is twice the transfer offset by the transfer unit 8. Therefore, by performing the operations (X2-X1) / 2 and (Y2-Y1) / 2, the transfer offsets in the X-axis and Y-axis directions can be calculated. Furthermore, in the case of no transfer offset by the transfer unit 8, the coordinates (X1, Y1) of the mark M before transfer and the coordinates (X2, Y2) of the mark M after transfer are the same.

[0044] After performing the transfer offset calculation process, it is preferable to add (X2-X1) / 2 and (Y2-Y1) / 2 to the movement of the transfer unit 8 to correct the transfer offset. In the illustrated embodiment, when transferring workpiece W from the first worktable 4 to the second worktable 6, the X-axis transfer unit transfers workpiece W in the X-axis direction, and the Y-axis transfer unit 11 transfers workpiece W in the Y-axis direction and vertical direction. Therefore, the transfer offset in the X-axis direction is added to the movement of the X-axis transfer unit, and the transfer offset in the Y-axis direction is added to the movement of the Y-axis transfer unit 11. This prevents transfer offset when transferring workpiece W from the first worktable 4 to the second worktable 6, and allows workpiece W to be placed at the appropriate position on the second worktable 6.

[0045] As described above, the illustrated embodiment includes the following steps: a first coordinate storage step, in which the workpiece W with the mark M is held on the first worktable 4, and the image is captured by the imaging unit 10, storing the coordinates of the mark M as X1 and Y1 coordinates; a 180-degree rotation step, in which the workpiece W held on the first worktable 4 is transferred to the second worktable 6 by the transfer unit 8 and held there, and the second worktable 6 is rotated 180 degrees; and a return step, in which the second worktable 6 is returned by the transfer unit 8. The workpiece W is transported to the first worktable 4 and held; in the second coordinate storage process, the first worktable 4 is rotated 180 degrees and the workpiece W is photographed by the imaging unit 10, and the coordinates of the mark M are stored as X2 and Y2 coordinates; and in the transport offset calculation process, (X2-X1) / 2 is used as the transport offset in the X-axis direction and (Y2-Y1) / 2 is used as the transport offset in the Y-axis direction, so the transport offset of the transport unit 8 can be easily calculated.

[0046] Furthermore, the conveying offsets in the X-axis and Y-axis directions can also be expressed as (X1-X2) / 2 and (Y1-Y2) / 2, respectively, in contrast to the illustrated embodiment. This is because half of the difference between X1 and X2 and half of the difference between Y1 and Y2 is the conveying offset, and the sign of the calculated value is positive (+) or negative (-) to indicate the direction in which the conveying offset occurs.

[0047] Furthermore, in the illustrated embodiment, a cutting device for performing cutting processing on workpiece W is described as an example constituting processing device 2. However, the present invention can be any device having a conveying unit for conveying workpieces such as semiconductor wafers between two or more worktables, and can be implemented in various processing devices including laser processing devices for performing laser processing on workpieces, grinding devices for performing grinding processing on workpieces, and inspection devices for inspecting workpieces.

Claims

1. A method for detecting conveying offset, wherein a conveying offset of a conveying unit is determined in a processing apparatus for processing a workpiece, the processing apparatus comprising at least a rotatable first worktable, a rotatable second worktable, a conveying unit for conveying a workpiece from the first worktable to the second worktable, and a photographing unit for photographing the workpiece held on the first worktable, wherein, The method for detecting conveying offset includes the following steps: In the first coordinate storage process, the marked workpiece is held on the first worktable and photographed using the imaging unit, and the coordinates of the marked workpiece are stored as X1 and Y1 coordinates. In the 180-degree rotation process, the workpiece held on the first worktable is transferred to the second worktable by the transfer unit and held there, while the second worktable is rotated 180 degrees. Returning to the process, the workpiece held on the second workbench is transferred to the first workbench via the transfer unit and held thereafter; The second coordinate storage process involves rotating the first worktable 180 degrees, using the imaging unit to photograph the workpiece, and storing the marked coordinates as X2 and Y2 coordinates; and The process of calculating the transport offset involves using (X2-X1) / 2 as the transport offset in the X-axis direction and (Y2-Y1) / 2 as the transport offset in the Y-axis direction.

2. The method for detecting conveying offset according to claim 1, wherein, The conveying offset is corrected by adding (X2-X1) / 2 and (Y2-Y1) / 2 to the movement of the conveying unit.

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