JP7618488B2 - Method for detecting conveyance deviation - Google Patents

Description

The present invention relates to a method for detecting the amount of deviation in conveyance of a conveying means that conveys a workpiece from a first table to a second table.

The wafer, on whose surface multiple devices such as ICs and LSIs are formed and partitioned along planned division lines, is then divided into individual device chips by a dicing machine, and each of the divided device chips is used in electrical equipment such as mobile phones and personal computers.

The dicing device is generally composed of a chuck table that holds the wafer, a cutting means that cuts the wafer held on the chuck table, an X-axis feed means that feeds the chuck table and the cutting means relatively in the X-axis direction, a Y-axis feed means that indexes and feeds the chuck table and the cutting means relatively in the Y-axis direction, an imaging means that images the wafer held on the chuck table and detects the area to be cut, a cleaning means that cleans the cut wafer, and a transport means that transports the wafer from the chuck table to the cleaning means, and can cut the wafer with high precision (see, for example, Patent Document 1). The cleaning means of the dicing device includes a spinner table that can hold and rotate the wafer, and a cleaning liquid injection nozzle that sprays a cleaning liquid onto the wafer held on the spinner table.

JP 2010-36275 A

However, if the wafer held in the correct position on the chuck table of the dicing device cannot be transported by the transport means to the correct position on the spinner table of the cleaning means, the high speed rotation of the spinner table may cause the wafer to fly off the spinner table. For this reason, it is necessary to actually measure the direction and distance from the chuck table to the spinner table and fine-tune the transport direction and transport distance of the transport means, but such fine adjustments are time-consuming and result in poor productivity.

Such problems can also occur in various processing devices (e.g., laser processing devices, grinding devices, inspection devices) that have a mechanism for transporting wafers between two or more tables.

In view of the above, the objective of the present invention is to provide a method for detecting conveyance deviation that can easily determine the conveyance deviation of the conveyance means.

According to the present invention, the following method for detecting a deviation in conveyance is provided to solve the above-mentioned problem. That is, in a processing device for processing a workpiece, the processing device is provided with at least a rotatable first table, a rotatable second table, a conveying means for conveying a workpiece from the first table to the second table, and an imaging means for imaging the workpiece held on the first table, and the method for detecting a deviation in conveyance of the conveying means includes a first coordinate storage step of holding a workpiece on which a mark is formed on the first table, imaging the workpiece with the imaging means, and storing the coordinates of the mark as X1, Y1 coordinates; The method includes a 180-degree rotation step of transporting the workpiece held on the second table by the transport means to the first table and holding the workpiece thereon, a return step of transporting the workpiece held on the second table by the transport means to the first table and holding the workpiece thereon, a second coordinate storage step of rotating the first table 180 degrees, capturing an image of the workpiece with the imaging means, and storing the coordinates of the mark as X2, Y2 coordinates, and a transport deviation calculation step of calculating (X2-X1)/2 as the transport deviation in the X-axis direction and (Y2-Y1)/2 as the transport deviation in the Y-axis direction.

Preferably, (X2-X1)/2 and (Y2-Y1)/2 are added to the movement amount of the conveying means to correct the conveying deviation.

The method for detecting a conveyance deviation of the present invention is a method for detecting a conveyance deviation of a conveyance means in a processing device that processes a workpiece and that is equipped with at least a rotatable first table, a rotatable second table, a conveyance means for conveying a workpiece from the first table to the second table, and an imaging means for imaging the workpiece held on the first table, and includes a first coordinate storage step of holding a workpiece on which a mark is formed on the first table, imaging the workpiece with the imaging means, and storing the coordinates of the mark as X1, Y1 coordinates, and a second coordinate storage step of conveying the workpiece held on the first table by the conveyance means to the second table, where the workpiece is held on the second table and imaged. The method includes a 180-degree rotation process in which the bull is rotated 180 degrees, a return process in which the workpiece held on the second table by the transport means is transported to the first table where it is held, a second coordinate storage process in which the first table is rotated 180 degrees, the workpiece is imaged by the imaging means, and the coordinates of the mark are stored as X2, Y2 coordinates, and a transport deviation calculation process in which (X2-X1)/2 is the transport deviation in the X-axis direction and (Y2-Y1)/2 is the transport deviation in the Y-axis direction. This makes it possible to easily determine the transport deviation of the transport means from the deviation in the coordinates of the mark without having to actually measure the direction and distance from the first table to the second table.

1 is a perspective view of a processing apparatus in which a method for detecting a conveyance deviation according to the present invention can be implemented; FIG. 4 is a plan view of a workpiece on which a mark is formed. FIG. 2 is a schematic plan view of the first and second tables shown in FIG. 1 . FIG. 11 is a schematic plan view of the first and second tables in a first coordinate storage process. 13 is a schematic plan view showing a state in which a workpiece held on a first table is transported by a transport means to a second table and held thereon. FIG. 6 is a schematic plan view showing a state in which the second table is rotated 180 degrees from the state shown in FIG. 5 . 13 is a schematic plan view showing a state in which a workpiece held on a second table is transported by a transport means to a first table and held thereon. FIG. 8 is a schematic plan view showing a state in which the first table is rotated 180 degrees from the state shown in FIG. 7 .

Below, a preferred embodiment of the transport deviation detection method of the present invention will be described with reference to the drawings.

First, a processing device in which the transport misalignment detection method of the present invention can be implemented will be described. The processing device 2 shown in FIG. 1 includes at least a rotatable first table 4, a rotatable second table 6, a transport means 8 for transporting a workpiece from the first table 4 to the second table 6, and an imaging means 10 for imaging the workpiece held on the first table 4.

The circular first table 4 is transported in the X-axis direction indicated by the arrow X in FIG. 1 by an X-axis transport means (not shown), and rotated by a first table motor (not shown) about the center C1 of the first table 4 (see FIG. 3). The X-axis transport means may, for example, include a ball screw connected to the first table 4 and extending in the X-axis direction, and a motor for rotating the ball screw. The Y-axis direction indicated by the arrow Y in FIG. 1 is perpendicular to the X-axis direction, and the XY plane defined by the X-axis and Y-axis directions is substantially horizontal.

As shown in FIG. 1, a porous circular suction chuck 4a connected to a suction means (not shown) is disposed on the upper end of the first table 4. The first table 4 is adapted to suction-hold a disk-shaped workpiece W (see FIG. 2), such as a semiconductor wafer, by generating a suction force on the suction chuck 4a using the suction means. Note that the processing device 2 in the illustrated embodiment is a dicing device that performs cutting processing on the workpiece W, and the first table 4 suction-holds the workpiece W when cutting processing is performed on the workpiece W.

The second table 6 in the illustrated embodiment is a spinner table that suctions and holds the workpiece W when cleaning the workpiece W that has been machined and has cutting chips attached to it. The circular second table 6 is rotated by a second table motor (not shown) around the center C2 of the second table 6 (see FIG. 3).

As shown in FIG. 1, a porous circular suction chuck 6a connected to a suction means (not shown) is disposed on the upper end of the second table 6, just like the first table 4. The second table 6 also suction-holds the workpiece W by generating a suction force on the suction chuck 6a using the suction means. The workpiece W can be cleaned by spraying cleaning liquid onto the workpiece W from a cleaning liquid spray nozzle (not shown) while rotating the second table 6 holding the workpiece W by suction.

The conveying means 8 in the illustrated embodiment includes the X-axis conveying means for conveying the workpiece W held on the first table 4 in the X-axis direction, and the Y-axis conveying means 11 for holding the workpiece W held on the first table 4, raising and lowering it, and conveying it in the Y-axis direction.

The Y-axis conveying means 11 includes an arm 12 that is movable in the Y-axis direction, an arm moving means (not shown) that moves the arm 12 in the Y-axis direction, a bracket piece 14 attached to the underside of the tip of the arm 12, an H-shaped plate 16 fixed to the underside of the bracket piece 14, and a number of suction pads 18 arranged on the underside of the plate 16. The arm moving means may be configured to have, for example, a ball screw connected to the arm 12 and extending in the Y-axis direction, and a motor that rotates the ball screw. The bracket piece 14 is configured to be able to freely expand and contract in the vertical direction by an appropriate actuator such as an air cylinder. In addition, each suction pad 18 is connected to a suction means (not shown).

In the conveying means 8, the X-axis conveying means positions the first table 4 at a predetermined conveying start position, and then the suction pad 18 of the Y-axis conveying means 11 suction-holds the workpiece W on the first table 4, and receives the workpiece W from the first table 4. Then, the Y-axis conveying means 11 that has received the workpiece W moves the arm 12 and bracket piece 14 to convey the workpiece W from the first table 4 to the second table 6.

The imaging means 10 is configured to image the workpiece W on the first table 4 that is positioned at a predetermined imaging position by the X-axis transport means. The image data captured by this imaging means 10 is sent to the control means (not shown) of the processing device 2.

The control means, which is made up of a computer, includes a central processing unit (CPU) that performs calculations according to a control program, a read-only memory (ROM) that stores the control program, and a readable/writable random access memory (RAM) that stores the calculation results. The control means performs image analysis on the image data sent from the imaging means 10, and for example, obtains and stores the X and Y coordinates of the mark M (see FIG. 2) formed on the workpiece W. The control means also controls the operation of the processing device 2, and as an example, controls the amount of movement of the transport means 8 according to conditions previously input to the control means.

As shown in FIG. 1, the processing device 2 further includes a cutting means 20 for cutting the workpiece W held on the first table 4, a cassette table 24 that can be raised and lowered and on which a cassette 22 containing a plurality of workpieces W is placed, a carrying means 28 for drawing out the unmachined workpiece W from the cassette 22 and carrying it to the temporary placement table 26 and carrying the machined workpiece W positioned on the temporary placement table 26 into the cassette 22, and a moving means 30 for moving the unmachined workpiece W carried from the cassette 22 to the temporary placement table 26 to the first table 4.

Next, a method for detecting the amount of deviation in conveyance of the conveying means 8 in the processing device 2 described above will be described. In the illustrated embodiment, a first coordinate storage step is first performed in which the workpiece W on which the mark M is formed is held on the first table 4, an image is captured by the imaging means 10, and the coordinates of the mark M are stored as X1, Y1 coordinates.

In the first coordinate storage process, first, the workpiece W is placed on the first table 4 with the surface on which the mark M is formed facing up. Next, the first table 4 is moved by the X-axis transport means and positioned at a predetermined imaging position, and the workpiece W held on the first table 4 is imaged by the imaging means 10. Then, image analysis is performed by the control means on the image captured by the imaging means 10, and the coordinates of the mark M are obtained and stored as X1, Y1 coordinates (see FIG. 4).

After the first coordinate storage process is performed, a 180-degree rotation process is performed in which the workpiece W held on the first table 4 is transported to and held on the second table 6 by the transport means 8, and the second table 6 is rotated 180 degrees.

In the 180-degree rotation process, first, the first table 4 is moved by the X-axis transport means, and the first table 4 is positioned at a predetermined transport start position. Once the first table 4 is positioned at the transport start position, the arm 12 and bracket piece 14 of the Y-axis transport means 11 are operated, and the suction pads 18 are brought into close contact with the top surface of the workpiece W on the first table 4. Next, the workpiece W is sucked and held by each suction pad 18, and the suction force of the first table 4 is released.

Then, the arm 12 and bracket piece 14 of the Y-axis transport means 11 are operated to transport the workpiece W from the first table 4 to the second table 6, and the bottom surface of the workpiece W is brought into contact with the top surface of the second table 6. Next, the workpiece W is suction-held by the second table 6, and the suction force of the suction pad 18 is released. In this manner, the workpiece W is transferred from the Y-axis transport means 11 to the second table 6 (see FIG. 5). Then, once the workpiece W has been transferred to the second table 6, the second table motor is operated, and the second table 6, which is holding the workpiece W by suction, is rotated 180 degrees as shown in FIG. 6.

After the 180-degree rotation process is performed, a return process is performed in which the workpiece W held on the second table 6 is transported by the transport means 8 to the first table 4 and held there.

In the return process, first, the suction pads 18 of the Y-axis transport means 11 are brought into close contact with the upper surface of the workpiece W on the second table 6, and the suction pads 18 suck and hold the workpiece W, while the suction force of the second table 6 is released. Next, the arm 12 and bracket piece 14 are operated to transport the workpiece W from the second table 6 to the first table 4, and the bottom surface of the workpiece W is brought into contact with the top surface of the first table 4. Then, as shown in FIG. 7, the workpiece W is sucked and held by the first table 4, while the suction force of the suction pads 18 is released. In this manner, the workpiece W is returned from the second table 6 to the first table 4.

After the return process is performed, the first table 4 is rotated 180 degrees, the workpiece W is imaged by the imaging means 10, and a second coordinate storage process is performed in which the coordinates of the mark M are stored as X2, Y2 coordinates.

In the second coordinate storage step, first, as shown in FIG. 8, the motor for the first table is operated to rotate the first table 4, which holds the workpiece W by suction, by 180 degrees. Next, the first table 4 is moved by the X-axis transport means and positioned at a predetermined imaging position, and the workpiece W held on the first table 4 is imaged by the imaging means 10. Then, image analysis is performed by the control means on the image captured by the imaging means 10, and the coordinates of the mark M are obtained and stored as X2, Y2 coordinates (see FIG. 8).

After the second coordinate storage process is performed, a transport deviation calculation process is performed to calculate (X2-X1)/2 as the transport deviation in the X-axis direction and (Y2-Y1)/2 as the transport deviation in the Y-axis direction. In the illustrated embodiment, the transport deviation is calculated by the control means.

In the illustrated embodiment, as described above, the workpiece W transported from the first table 4 to the second table 6 is rotated 180 degrees on the second table 6, and the workpiece W transported (returned) from the second table 6 to the first table 4 is rotated 180 degrees on the first table 4. Therefore, if there is a transport deviation due to the transport means 8, the distance between the coordinates (X1, Y1) of the mark M before transport and the coordinates (X2, Y2) of the mark M after transport is twice the transport deviation amount of the transport means 8. Therefore, by performing the calculations (X2-X1)/2 and (Y2-Y1)/2, the transport deviation amount in each of the X-axis direction and the Y-axis direction can be obtained. Note that, if there is no transport deviation due to the transport means 8, the coordinates (X1, Y1) of the mark M before transport and the coordinates (X2, Y2) of the mark M after transport match.

After carrying out the transport deviation calculation process, it is preferable to add (X2-X1)/2 and (Y2-Y1)/2 to the movement amount of the transport means 8 to correct the transport deviation. In the illustrated embodiment, when transporting the work W from the first table 4 to the second table 6, the X-axis transport means transports the work W in the X-axis direction, and the Y-axis transport means 11 transports the work W in the Y-axis direction and up and down directions, so the transport deviation amount in the X-axis direction is added to the movement amount of the X-axis transport means, and the transport deviation amount in the Y-axis direction is added to the movement amount of the Y-axis transport means 11. This makes it possible to prevent transport deviation from occurring when the work W is transported from the first table 4 to the second table 6, and to place the work W in the correct position on the second table 6.

As described above, the illustrated embodiment includes a first coordinate storage step in which the work W on which the mark M is formed is held on the first table 4, an image is taken by the imaging means 10, and the coordinates of the mark M are stored as X1, Y1 coordinates; a 180-degree rotation step in which the work W held on the first table 4 is transported by the transport means 8 to the second table 6 where it is held and the second table 6 is rotated 180 degrees; a return step in which the work W held on the second table 6 is transported by the transport means 8 to the first table 4 where it is held; a second coordinate storage step in which the first table 4 is rotated 180 degrees, the work W is imaged by the imaging means 10, and the coordinates of the mark M are stored as X2, Y2 coordinates; and a transport deviation calculation step in which (X2-X1)/2 is the transport deviation in the X-axis direction and (Y2-Y1)/2 is the transport deviation in the Y-axis direction, so that the transport deviation of the transport means 8 can be easily determined.

The amount of transport deviation in the X-axis and Y-axis directions may be (X1-X2)/2 and (Y1-Y2)/2, respectively, as opposed to the illustrated embodiment. Half the difference between X1 and X2, and half the difference between Y1 and Y2, are the amount of transport deviation, and whether the sign of the calculated numerical value is positive or negative indicates the direction in which the transport deviation is occurring.

In addition, in the illustrated embodiment, an example has been described in which the processing device 2 is configured as a dicing device that performs cutting processing on the workpiece W, but the present invention can be implemented in various processing devices, including a laser processing device that performs laser processing on the workpiece, a grinding device that performs grinding processing on the workpiece, and an inspection device that inspects the workpiece, as long as it is equipped with a transport means for transporting a workpiece such as a semiconductor wafer between two or more tables.

2: Processing device 4: First table 6: Second table 8: Conveying means 10: Imaging means W: Work

Claims (2)

A processing apparatus for processing a workpiece, the processing apparatus comprising at least a rotatable first table, a rotatable second table, a transport means for transporting a workpiece from the first table to the second table, and an imaging means for imaging the workpiece held on the first table, the method comprising the steps of:
a first coordinate storage step of holding a workpiece on which a mark is formed on the first table, capturing an image of the workpiece with the imaging means, and storing coordinates of the mark as X1, Y1 coordinates;
a 180-degree rotation step of transporting the work held on the first table to the second table by the transport means, and rotating the second table by 180 degrees;
a returning step of transporting the work held on the second table by the transport means to the first table and holding the work thereon;
a second coordinate storage step of rotating the first table 180 degrees, capturing an image of the workpiece with the imaging means, and storing coordinates of the mark as X2, Y2 coordinates;
a transfer deviation amount calculation step of calculating (X2-X1)/2 as the transfer deviation amount in the X-axis direction and (Y2-Y1)/2 as the transfer deviation amount in the Y-axis direction;
A method for detecting a conveyance deviation including the steps of: The method for detecting the amount of deviation in conveyance according to claim 1, in which (X2-X1)/2 and (Y2-Y1)/2 are added to the amount of movement of the conveyance means to correct the deviation in conveyance.

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