JP2004186306A - Detecting method of center of wafer, and pickup method and device for semiconductor chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a center detecting method for a wafer as well as a pickup method and device for a semiconductor chip, which are capable of easily detecting the center and the diameter of the wafer with a high accuracy while capable of being applied on a partially annular wafer whose outer peripheral end forms an outer peripheral circle only partially. <P>SOLUTION: A first to third reference image data D<SB>1</SB>to D<SB>3</SB>are formed based on a reference image data comprising the outer peripheral end of an imaginary wafer having the same arc as that of the wafer 1, then the image of outer peripheral end of the wafer is photographed to compare respective photographed images with the first to third reference image data, and to detect mutually coincident positions as a first to third end positions P<SB>1</SB>to P<SB>3</SB>. The plane coordinates of the center Ow of the outer peripheral circle formed by the outer peripheral end of the wafer and the diameter of the same are operated based on respective plane coordinates of the detected first to third end positions. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of detecting the center of a wafer diced so that a plurality of semiconductor chips are arranged in a lattice, and a method and an apparatus for picking up semiconductor chips from each of the wafers.
[0002]
[Prior art]
Conventionally, in this type of semiconductor chip pickup method and apparatus, each of the semiconductor chips is individually pushed up from the lower surface thereof from a single disk-shaped wafer having a plurality of semiconductor chips divided in a lattice by dicing. As a result, an operation of picking up (ie, taking out) each of the semiconductor chips from the wafer is performed in a state in which the semiconductor chips can be picked up.
[0003]
Further, such a wafer is generally diced in a state of being attached to a stretchable wafer sheet, and thereafter, in a state where the wafer sheet is radially stretched, together with the wafer sheet, The wafer is mounted on the pickup device. Therefore, the arrangement of the respective semiconductor chips is also in a state of being radially extended, that is, in a so-called expanded state.
[0004]
On the other hand, in the pickup device, it is required that the arrangement of each of the semiconductor chips in the expanded state is accurately recognized and a reliable pickup operation can be performed. In addition, it is necessary to recognize the arrangement of the respective semiconductor chips in consideration of the displacement between the center of the mounting position of the wafer to the pickup device and the center position of the wafer.
[0005]
Therefore, in the conventional pickup method and apparatus, the center and radius of the outer circumference formed by the outer circumference of the wafer mounted on the pickup apparatus are calculated, and the arrangement coordinates of the respective semiconductor chips are accurately recognized. Various methods have been used.
[0006]
For example, according to the method described in Patent Literature 1, in a pickup device, a wafer is arranged on an upper surface of a wafer holding table, and the upper surface of the wafer holding table is an XY plane, and the maximum position and the minimum position in the Y-axis direction are obtained. By detecting the outer peripheral end position of the wafer as planar coordinates using a recognition camera, using the respective planar coordinates of the maximum position and the minimum position, the center and radius of the outer peripheral circle are calculated. I have.
[0007]
[Patent Document 1]
JP-A-10-12706
[0008]
[Problems to be solved by the invention]
However, in such a method, even if it is possible to detect the outer peripheral edge position of the wafer by the recognition camera, the detected outer peripheral edge position is the maximum position in the Y-axis direction or the maximum It is not easy to recognize that the position is the minimum position, and there is a problem that the recognition process is complicated.
[0009]
Therefore, the position detected as the maximum position or the minimum position may actually be a position deviated from the maximum position or the minimum position. The center and radius of the outer circumferential circle of the wafer calculated based on the above may be different from the actual ones, and the arrangement of the respective semiconductor chips may not be accurately recognized.
[0010]
Further, since the center and radius of the outer peripheral circle of the wafer are calculated from the two points of the maximum position and the minimum position, a calculation error is likely to occur, and it may not be possible to cope with higher precision recognition. There are points.
[0011]
In addition, a partially circular wafer whose outer peripheral edge only partially forms an outer peripheral circle, such as a 円 circular wafer or a ４ circular wafer used particularly in a test or development stage. In this case, the above method cannot calculate the center and radius of the outer peripheral circle of the wafer, and there is a problem that the shape of the wafer used in the pickup device is limited.
[0012]
There is also a method of performing pickup without recognizing the outer peripheral edge of the wafer. In this case, the recognition operation is performed at a predetermined position on the assumption that the wafer attachment position is not shifted by one pitch or more, and the deviation of the component at that time is regarded as the wafer attachment position shift. Was taken. However, in such a method, there is a problem that the smaller the size of the semiconductor chip, the higher the accuracy of attaching the wafer to the sheet. In addition, there is also a problem that if the pitch is shifted by one pitch or more, the part is left unreliably. Furthermore, because the sheet is expanded, if the sheet does not always reproduce the same amount of elongation due to ambient temperature, sheet quality, etc., variations in the diameter will occur. Or a wasteful recognition operation (when only the set size is reduced).
[0013]
Accordingly, an object of the present invention is to solve the above-described problems, and to easily detect the center and the diameter of a wafer diced so that a plurality of semiconductor chips are arranged in a lattice with high accuracy. And a method of detecting the center of a wafer that can be applied to a partially circular wafer in which the outer peripheral edge of the wafer only partially forms an outer peripheral circle. An object of the present invention is to provide a semiconductor chip pickup method and apparatus for picking up a semiconductor chip.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
[0015]
According to a first aspect of the present invention, in a method for detecting the center of a wafer diced so that a plurality of semiconductor chips are arranged in a grid,
The first reference image data including a part of the outer peripheral edge of the virtual wafer having the same arc as the previously created wafer is compared with the captured image of the outer peripheral edge of the wafer, and matched with each other. Is detected as a first end position,
The second reference image data obtained by rotating the first reference image data by a predetermined angle is compared with a captured image of an outer peripheral end of the wafer, and positions matching each other are determined by the second end. Detected as a position,
The third reference image data in which the first reference image data is rotated by an angle different from the predetermined angle is compared with an image taken of the outer peripheral end of the wafer, and a position matching each other is determined. 3 detected as the end position,
The plane of the center of the outer circumference formed by the outer peripheral edge of the wafer based on the planar coordinates along the surface of the wafer from the detected first end position to the third end position. A method of detecting a center of a wafer, comprising calculating coordinates and a diameter thereof.
[0016]
According to a second aspect of the present invention, in a semiconductor chip pickup method for picking up the semiconductor chip from a wafer diced so that a plurality of semiconductor chips are arranged in a lattice,
The reference image data including a part of the outer peripheral edge of the virtual wafer having the same arc as the previously created wafer is read out as the first reference image data, and an image of the outer peripheral edge of the wafer is captured. And comparing the captured image with the first reference image data to detect a position that matches each other as a first end position,
The first reference image data rotated by a predetermined angle is used as second reference image data, and an image of the outer peripheral edge of the wafer is captured. The captured image and the second reference image are captured. By comparing the data with the data, a position matching each other is detected as a second end position,
The first reference image data rotated by an angle different from the predetermined angle is used as third reference image data, and an image of an outer peripheral end of the wafer is captured. 3 is compared with the reference image data, a position that matches each other is detected as a third end position,
The plane of the center of the outer circumference formed by the outer peripheral edge of the wafer based on the planar coordinates along the surface of the wafer from the detected first end position to the third end position. Calculate the coordinates and their diameter,
There is provided a semiconductor chip pickup method for correcting the plane coordinates at the arrangement position of each of the semiconductor chips based on the calculation result and picking up each of the semiconductor chips.
[0017]
According to the third aspect of the present invention, the comparison between the respective reference image data and the respective captured images is performed by comparing all or a part of the outer peripheral edge of the wafer in the captured images with the reference image. The semiconductor chip pick-up method according to the second aspect is provided, wherein the method is performed by detecting a position where the entire outer peripheral end of the virtual wafer in the image data matches.
[0018]
According to a fourth aspect of the present invention, there is provided the semiconductor chip pickup method according to the second or third aspect, wherein the third reference image data is created by rotating the second reference image data. provide.
[0019]
According to a fifth aspect of the present invention, the reference image data is image data created so as not to display dicing lines on the virtual wafer,
Collating each image of the outer peripheral end of the wafer imaged with the focal position of the imaging shifted so that the dicing line of the wafer is blurred, and each reference image data in which the dicing line is not displayed The method for picking up a semiconductor chip according to any one of the second to fourth aspects of the present invention is provided.
[0020]
According to the sixth aspect of the present invention, as the wafer, any one of the second aspect to the fifth aspect, in which a partially circular wafer whose outer peripheral edge forms a part of the outer peripheral circle is used. And a method for picking up a semiconductor chip.
[0021]
According to the seventh aspect of the present invention, a semiconductor chip for picking up each of the semiconductor chips by a pickup head from a holding table on which a wafer diced so that a plurality of semiconductor chips are arranged in a lattice pattern is arranged. In the pickup device of
An imaging device for capturing an image of the surface of the wafer,
A moving device that relatively moves the imaging device and the holding table along the surface of the wafer;
A control device for controlling the operation of the imaging device and the moving device,
The control device includes:
The reference image data is created as first reference image data based on the reference image data including a part of the outer peripheral edge of the virtual wafer having the same arc as the previously created wafer, and rotated by a predetermined angle. A reference image for generating the obtained first reference image data as second reference image data, and generating the first reference image data rotated by an angle different from the predetermined angle as third reference image data A data creation unit,
By controlling the moving device and the imaging device, while performing the relative movement by the moving device, the image of the outer peripheral end of the wafer imaged by the imaging device, and from the first reference image data An end position detection unit for comparing the third reference image data with the respective reference image data and detecting plane coordinates along the surface of the wafer at respective end positions that match each other;
The plane coordinates and the diameter of the center of an outer peripheral circle formed by the outer peripheral end of the wafer are calculated based on the plane coordinates of the respective end positions, and the respective semiconductor chips are calculated based on the calculation results. And an arrangement position correction processing unit for correcting the plane coordinates at the arrangement position of the semiconductor chip.
[0022]
According to an eighth aspect of the present invention, the reference image data creation section rotates the second reference image data to create the third reference image data. Provide equipment.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
FIG. 1 is a schematic explanatory view showing a schematic configuration of a pickup device 101 which is an example of a method and an apparatus for picking up a semiconductor chip according to an embodiment of the present invention.
[0025]
As shown in FIG. 1, a pickup device 101 includes a wafer holding unit 20 that holds a disk-shaped wafer 1 and a die 2 that is an example of each semiconductor chip in which the wafer 1 is diced and arranged in a lattice. A push-up nozzle 14 for pushing up the die 2 from its lower surface, a pick-up head 12 for performing a pick-up operation of sucking and holding the die 2 pushed up by the push-up nozzle 14 on its upper surface and taking it out of the wafer 1. An imaging camera 10 is provided as an example of an imaging device that recognizes an arrangement position of each die 2 by imaging an image of each die 2 of the wafer 1 placed and held by the wafer holding unit 20. .
[0026]
As shown in FIG. 1, the wafer holding unit 20 has a substantially U-shaped cross-section, and has a holding table 21 capable of holding the wafer 1 on its upper surface 21a. And a Y-axis direction moving device 22 that is an example of a moving device that moves forward and backward along the Y-axis direction, which is one direction along the surface of the device.
[0027]
The wafer sheet 3 for attaching the wafer 1 to its upper surface has elasticity, and is attached to the wafer plate 4 at its end, and the wafer plate 4 is detachably attached to the upper surface 21 a of the holding table 21. Installed.
[0028]
Here, an enlarged schematic explanatory view of the wafer plate 21 is shown in FIG. As shown in FIG. 2, the wafer 1 is attached to the upper surface of the wafer sheet 3 in a state where the edge is extended by the wafer plate 4. The wafer plate 4 has a disc-shaped hollow hole 4a, and the wafer 1 is disposed in the hollow hole 4a. The wafer 1 is diced, and has a plurality of dies 2 arranged in a grid in a direction along the surface of the wafer 1. Further, the wafer sheet 3 is radially stretched while being attached to the wafer plate 4, and the arrangement of the respective dies 2 arranged in the lattice pattern is radially stretched (that is, expanded). As a result, a gap is formed between the ends of the dies 2 adjacent to each other so as not to contact each other. As described above, since the gaps are formed, when each of the dies 2 is picked up from the wafer 1, the dies 2 to be picked up contact the adjacent dies 2 and affect the respective arrangements. Has been prevented.
[0029]
As shown in FIG. 1, a disc-shaped hollow hole 21b similar to the hollow hole 4a of the wafer plate 4 is also formed on the upper surface 21a of the holding table 21, and the wafer plate 4 has the hollow hole. The portion 4a is mounted on the upper surface 21a of the holding table 21 such that the center of the portion 4a substantially matches the center of the hollow hole portion 21b in a plane.
[0030]
Further, as shown in FIG. 1, the push-up nozzle 14 is arranged inside the U-shaped cross section of the holding table 21 so that its tip is planarly located inside the hollow hole 21b. Are located. Further, the push-up nozzle 14 is provided with an elevating device (not shown) for performing an ascending / descending operation of the tip thereof, and the tip 2 is individually pushed up from the lower surface of the wafer sheet 4 by raising the tip. It is possible.
[0031]
The pickup head 12 is provided with a suction nozzle 12a that can hold the die 2 by suction by contacting the top end of the pickup head 12 with the upper surface of the die 2. Further, the pickup nozzle 12a moves up and down. An elevating device (not shown) is provided. Thereby, the suction nozzle 12a is lowered so that the top end of the suction nozzle 12a comes into contact with the upper surface of the die 2 pushed up by the push-up nozzle 14, and the die 2 is suction-held and then raised. Thereby, the die 2 can be separated from the wafer sheet 3 and picked up. When this pickup operation is performed, the pickup head 12 and the push-up nozzle 14 are arranged so that the tip end of the push-up nozzle 14 is located vertically below the tip end of the suction nozzle 12a.
[0032]
Further, the imaging camera 10 includes an imaging element (not shown) such as a CCD, and can capture an image of the surface of the wafer 1 or the surface of the wafer sheet 3. Further, the imaging camera 10 has a zoom function, and using this zoom function, it is possible to individually image each die 2 or collectively image the images of a plurality of dies 2. ing.
[0033]
The imaging camera 10, the pickup head 12, and the push-up nozzle 14 can be individually moved along the X-axis direction, which is one direction along the surface of the wafer 1, and the imaging camera 10 is an example of a moving device. The pickup head 12 can be moved by a pickup head moving device 13 which is an example of a moving device, and the push-up nozzle 14 can be moved by a push-up nozzle moving device 15 which is an example of a moving device. (Note that these moving devices are collectively referred to as X-axis direction moving devices 11, 13, and 15). In addition, instead of such a case where the respective X-axis direction moving devices 11, 13, and 15 are individually provided in the imaging camera 10, the pickup head 12, and the push-up nozzle 14, respectively, collectively. It may be the case that one X-axis direction moving device is provided. In such a case, the movement in the X-axis direction is performed in a state where the imaging camera 10, the pickup head 12, and the push-up nozzle 14 are integrated while maintaining a relative relationship with each other. Become. Note that the X-axis direction and the Y-axis direction are directions orthogonal to each other.
[0034]
Further, in the pickup device 101, since the respective X-axis direction moving devices 11, 13, 15 and the Y-axis direction moving device 22 are provided, each of the imaging camera 10, the pickup head 12, and the push-up nozzle 14 can be controlled. , Relative to the wafer 1 in the X-axis direction or the Y-axis direction. In the pickup device 101, each of the imaging camera 10, the pickup head 12, and the push-up nozzle 14 may be configured to be movable in the X-axis direction or the Y-axis direction relative to the wafer 1. For example, instead of a case where the wafer holding unit 20 includes only the Y-axis direction moving device 22 as the moving device, a case where the wafer holding unit 20 also includes an X-axis direction moving device may be used.
[0035]
As shown in FIG. 1, the pickup device 101 includes an imaging operation of the imaging camera 10, an adsorption operation of the pickup head 12, an upward operation of the upward nozzle 14, and a moving operation of each of the X-axis direction moving devices 11, 13, and 15. , And a control device 30 that controls each of the movement operations of the Y-axis direction movement device 22. The control unit 30 controls the above operations in association with each other, and performs the pickup operation of each die 2 of the wafer 1.
[0036]
Next, the configuration of the control device 30 will be described with reference to the block diagram shown in FIG. In the block diagram shown in FIG. 6, only the main configuration is shown for convenience of explanation.
[0037]
As shown in FIG. 6, the control device 30 that controls the operation of each component in the pickup device 101 includes, as a core part thereof, a central processing unit 39 that integrally controls the operation of each component. The central processing unit 39 includes a pickup control unit 40 that controls the operation of each component of the pickup device 101. The pickup control unit 40 includes an imaging control unit 36 that controls the imaging operation of the imaging camera 10, and an X-axis direction movement control unit 37 that controls the movement operation of each of the X-axis direction moving devices 11, 13, and 15. And a Y-axis direction movement control unit 38 that controls the movement operation of the Y-axis direction movement device 22. In addition, the central processing unit 39 includes a memory unit 31 that stores the operation result and external input data in a retrievable manner.
[0038]
Further, in the present embodiment, the positions of a plurality of outer peripheral edges of the wafer 1 are detected using image data, and the outer peripheral circle formed by the outer peripheral edges of the wafer 1 is determined based on the respective detection results. The radius is calculated as the center and diameter. Further, based on the calculation result, the arrangement position of each die 2 on the wafer 1 is corrected, and the recognition processing of the actual arrangement position of each die 2 is performed. Further, even if the respective wafers 1 have the same size, the positions of the respective components in the wafer 1 may be different depending on the dicing patterning. Based on the recognition result, the displacement amount is detected from the recognition result, and the final arrangement position of each component is recognized.
[0039]
In order to perform such recognition processing, as shown in FIG. 6, the central processing unit 39 further generates reference image data for handling image data serving as reference data for detection in detecting the outer peripheral edge of the wafer 1. Unit 33, an end position detecting unit 34 for comparing an image actually picked up by the imaging camera 10 with the reference image data, and detecting an outer peripheral end position of the wafer 1, and an end position detecting unit 34 The center and radius of an outer peripheral circle formed by the outer peripheral end of the wafer 1 are calculated based on the outer peripheral end position of the wafer 1 detected by the unit 34, and the arrangement of each die 2 is calculated based on the calculation result. An arrangement position correction processing unit 35 for correcting the position is provided. The detailed operations of the reference image data creation unit 33, the end position detection unit 34, and the arrangement position correction processing unit 35 will be described later. The central processing unit 39 includes a memory unit 31, a reference image data creation unit 33, an end position detection unit 34, an arrangement position correction processing unit 35, and a control unit 32 that integrally controls the pickup control unit 40. Provided.
[0040]
Next, in the pick-up device 101, when performing the pick-up operation of each die 2 from the wafer 1 held on the upper surface 21a of the holding table 21, the expansion and the dislocation of the wafer 1 to the holding table 21 are considered. A method for detecting the arrangement position of each die 2 will be described.
[0041]
Hereinafter, a method for detecting the center and radius of the outer peripheral circle of the wafer 1 will be described with reference to FIGS. 3 is a schematic plan view of the wafer 1 mounted on the wafer plate 4, FIG. 4 shows some types of reference image data, and FIG. It is a flowchart which shows the procedure of the detection method of a radius.
[0042]
As shown in FIG. 3, the wafer 1 mounted on the wafer plate 4 is arranged and held on the upper surface 21a of the holding table 21, but the mounting state of the wafer 1 on the wafer plate 4 and the holding table of the wafer plate 4 Due to the above arrangement on the center 21, it is difficult to completely match the center Ow of the wafer 1 and the center Ot of the holding table 21 in a planar manner. A planar displacement often occurs between them.
[0043]
Further, since the wafer 1 is expanded by stretching the wafer sheet 3, the radius of the outer peripheral circle formed by the outer peripheral end portion also differs depending on the expanded state. Therefore, the planar arrangement position of each die 2 on the wafer 1 also differs for each individual wafer 1.
[0044]
On the other hand, in the pickup device 101, it is necessary to perform a pickup operation after accurately recognizing the planar arrangement position of each die 2 on the wafer 1 arranged on the holding table 21.
[0045]
For this reason, in the pickup device 101, the outer peripheral circle formed by the wafer 1 is specified by detecting at least three or more end positions at the outer peripheral end of the wafer 1 placed on the holding table 21, ie, The center and radius of the outer circle are calculated. Further, based on the calculation result, the arrangement position of each die 2 with respect to the center Ow of the wafer 1 which is set in advance is recognized as plane coordinates with respect to the center Ot of the holding table 21 so that the arrangement of each die 2 is determined. The position is being corrected.
[0046]
In detecting the position of the outer peripheral edge of the wafer 1, image data including a part of the outer peripheral edge of the virtual wafer having the same arc as the wafer 1 arranged on the holding table 21 is used as the reference image data. By comparing the image data of the outer peripheral edge of the wafer 1 actually imaged by 10 with the reference image data, a position that matches each other is detected as the outer peripheral edge position.
[0047]
Here, the virtual wafer having the same circular arc as the wafer 1 is a virtual wafer having the same circular arc as a part of the circular arc formed by the outer peripheral edge of the wafer 1. In other words, it is a virtual wafer having the same diameter as the wafer 1 and a virtual wafer having an arc having the same radius of curvature as the outer circumference of the wafer 1. Note that one real wafer can be used as a virtual wafer.
[0048]
FIG. 4 shows an example of the “reference image data”. As shown in FIG. 4A, the “reference image data” is a planar image including the same circular arc as the wafer 1 and including a part of the outer peripheral end of the expanded virtual wafer 51. Image data. In the reference image data, at least the surface portion of the virtual wafer 51 and a portion other than the surface portion of the virtual wafer 51 need to be clearly displayed. Therefore, for example, the reference image data D shown in FIG. ₀ In the above, an image in which the outer peripheral end of the virtual wafer 51 which is the boundary between the surface portion of the virtual wafer 51 and a portion other than the surface portion of the virtual wafer 51 is displayed near the diagonal of the substantially square image area abcd is used. Have been. Further, such reference image data D ₀ Can be created in advance, input to the control device 30, and stored in the memory unit 31. In the case where a plurality of types of wafers 1 are used in the pickup device 101, reference image data corresponding to each of them is created in advance, stored in the memory unit 31, and handled. In some cases, appropriate reference image data is selectively read from the memory unit 31 according to one type. The reference image data D shown in FIG. ₀ Is an example. For example, the reference image data D having an image area in which the image area abcd in FIG. ₀ It may be.
[0049]
In the reference image data creation unit 33, the reference image data D stored in the memory unit 31 is stored. ₀ Is read, and the read reference image data D ₀ Is rotated in a plane by a predetermined angle, a plurality of reference image data can be created. For example, the reference image data D ₀ To the first reference image data D ₁ And the first reference image data D ₁ Is rotated by 90 degrees in a counterclockwise direction with a predetermined angle as the second reference image data D ₂ And the first reference image data D ₁ Is rotated counterclockwise by 180 degrees as an angle different from the above predetermined angle, and the third reference image data D ₃ And the first reference image data D ₁ Are rotated by 270 degrees counterclockwise as angles different from the above respective angles, and the fourth reference image data D ₄ , A plurality of pieces of reference image data are created. That is, the first to fourth reference image data D ₁ ~ D ₄ Is the first reference image data D ₁ (Or the reference image data D ₀ ), The reference image data is created by being rotated by different angles, so that the respective created reference image data are different from each other. Therefore, it is clear that the predetermined angle is not an angle that is an integral multiple of 360 degrees so as to obtain the same result as at least 0 degrees or substantially 0 degrees. Further, the rotation direction may be either a counterclockwise direction or a clockwise direction.
[0050]
Also, as described above, the first reference image data D ₁ As a specific method for creating each reference image data based on the reference image data, for example, reference image data D ₀ To the first reference image data D ₁ And the first reference image data D ₁ Is rotated by 90 degrees in a counterclockwise direction with a predetermined angle as the second reference image data D ₂ And the second reference image data D ₂ Is rotated counterclockwise by 90 degrees to obtain third reference image data D ₃ And the third reference image data D ₃ Is rotated 90 degrees counterclockwise to form the fourth reference image data D ₄ , A plurality of pieces of reference image data are created. Also, the reference image data D ₀ Are sequentially rotated to obtain the second to fourth reference image data D. ₂ ~ D ₄ May be created.
[0051]
Further, the first to fourth reference image data D ₁ , D ₂ , D ₃ , D ₄ , One point on each outer peripheral end is defined as a first end position P as a detection end position. ₁ , The second end position P ₂ , Third end position P ₃ , Fourth end position P ₄ Is set as In FIG. 3, the first to fourth reference image data D ₁ , D ₂ , D ₃ , D ₄ Are superimposed on each other. An arbitrary position can be set as a rotation center in the rotation of the reference image data. ₀ Can be used as the center of rotation. In addition, the first to fourth end positions P ₁ ~ P ₄ Are the first to fourth reference image data D ₁ ~ D ₄ Are desirably located near the center of each image area. This is because, in the case of being located near the center, a more accurate detection can be made in image collation to be described later than in the case of being located near the end of each image area.
[0052]
Further, in FIG. 3, when it is assumed that the center Ow of the wafer 1 matches the center Ot of the holding table 21 in FIG. 3, the end position detection unit 34 can capture an image similar to each reference image data. An actual image including a part of the outer peripheral edge of the wafer 1 at a position estimated to be captured is captured, and the captured image and the reference image data are captured and compared with each other. A position matching the reference image data is detected. For example, the captured image and the first reference image data D ₁ Is compared with the first reference image data D in the captured image. ₁ Is detected, and the first end position P ₁ (That is, the XY coordinates in FIG. 3) can be detected. In addition, in the captured image, it is necessary that the image of at least the surface of the wafer 1 and the surface of the wafer sheet 3 are captured, and the outer peripheral edge of the wafer 1 which is the boundary between the two is clearly displayed. Need to be. For this reason, in the present embodiment, for example, the outer peripheral edge is clearly displayed by using the difference between the amount of reflected light from the surface of the wafer 1 and the amount of reflected light from the surface of the wafer sheet 3 in capturing an image. I have. Further, the image area of each of the captured images needs to be the same as or larger than the image area abcd of each reference image data. This is because, in the comparison of the image, the position where all or a part of the outer peripheral edge of the wafer 1 in the captured image matches the entire outer peripheral edge of the virtual wafer 51 in the reference image data is matched. This is because the detection is performed. In addition, this image collation is performed in a state where the magnification of each of the created reference image data and the magnification of the captured image are the same. This is for preventing the curvature of the outer peripheral end portion from being changed due to the difference in the magnification and performing the accurate matching.
[0053]
In the arrangement position correction processing unit 35, the first end position P detected by the end position detection unit 34 is used. ₁ From the fourth end position P ₄ The plane coordinates and the radius of the center of the outer peripheral circle formed by the outer peripheral edge of the wafer 1 are calculated based on the respective planar coordinates up to. Thereby, the relationship between the outer circumference of the wafer 1 placed on the holding table 21 and the center Ot of the holding table 21 can be calculated. Based on the calculation result, the correction of the arrangement position of each die 2 can be performed. That is, the arrangement position of each die 2 can be recognized as plane coordinates with respect to the center Ot of the holding table 21.
[0054]
Next, a specific procedure of a method for detecting the center and radius of the outer peripheral circle of the wafer 1 will be described with reference to the flowchart of FIG.
[0055]
First, as preparation for starting the above detection, reference image data D created in advance ₀ Is input to the control device 30 and stored in the memory unit 31.
[0056]
Next, in step S1 of FIG. 5, the reference image data D ₀ And the reference image data D read out by the reference image data ₀ To the first reference image data D ₁ Create as Instead of such a case, the end position detection unit 34 stores the reference image data D ₀ And reads it as it is as the first reference image data D ₁ May be adopted.
[0057]
Next, in step S2, the holding table 21 is moved in the Y-axis direction by the Y-axis direction moving device 22, and the imaging camera 10 is moved in the X-axis direction by the imaging camera moving device 11, respectively. ₁ First end position P ₁ The imaging camera 10 is located at a position where an image including a part of the outer peripheral end of the wafer 1 estimated to be located can be captured, and the imaging camera 10 captures the image.
[0058]
Then, in step S3, the captured image and the first reference image data D ₁ Is input to the end position detection unit 34, the images are compared with each other, and the positions that match each other are detected, whereby the first end position P ₁ The plane coordinates of are detected. The detected plane coordinates are output to the arrangement position correction processing unit 35. Instead of such a case, the plane coordinates may be temporarily stored in the memory unit 31.
[0059]
Next, in step S4, the first reference image data D ₁ Is rotated in the counterclockwise direction by 90 degrees in a plane to obtain the second reference image data D. ₂ Create as
[0060]
Next, in step S5, the holding table 21 is moved in the Y-axis direction by the Y-axis direction moving device 22, and the imaging camera 10 is moved in the X-axis direction by the imaging camera moving device 11, respectively. ₂ Second end position P of ₂ The imaging camera 10 is positioned at a position where an image including a part of the outer peripheral end of the wafer 1 estimated to be located can be captured, and the imaging camera 10 captures the image.
[0061]
Then, in step S6, the captured image and the second reference image data D ₂ Are captured by the end position detection unit 34, the images are compared with each other, and the positions that match each other are detected, whereby the second end position P ₂ The plane coordinates of are detected. The detected plane coordinates are output to the arrangement position correction processing unit 35.
[0062]
Further, in step S7, the reference image data creation unit 33 causes the second reference image data D ₂ Is rotated counterclockwise by 90 degrees in a plane to obtain third reference image data D ₃ Create as
[0063]
Next, in step S8, the holding table 21 is moved in the Y-axis direction by the Y-axis direction moving device 22, and the imaging camera 10 is moved in the X-axis direction by the imaging camera moving device 11, respectively. ₃ Third end position P of ₃ The imaging camera 10 is positioned at a position where an image including a part of the outer peripheral end of the wafer 1 estimated to be located can be captured, and the imaging camera 10 captures the image.
[0064]
Then, in step S9, the captured image and the third reference image data D ₃ Is captured by the end position detection unit 34, the images are compared with each other, and a position that matches each other is detected, so that the third end position P ₃ The plane coordinates of are detected. The detected plane coordinates are output to the arrangement position correction processing unit 35.
[0065]
Further, similarly, in step S10, the reference image data creation unit 33 causes the third reference image data D ₃ Is rotated counterclockwise by 90 degrees in a plane to obtain the fourth reference image data D ₄ Create as
[0066]
Next, in step S11, the holding table 21 is moved in the Y-axis direction by the Y-axis direction moving device 22, and the imaging camera 10 is moved in the X-axis direction by the imaging camera moving device 11, respectively. ₄ Fourth end position P of ₄ The imaging camera 10 is positioned at a position where an image including a part of the outer peripheral end of the wafer 1 estimated to be located can be captured, and the imaging camera 10 captures the image.
[0067]
Then, in step S12, the captured image and the fourth reference image data D ₄ Are taken into the end position detection unit 34, the images are compared with each other, and the positions that match each other are detected, so that the fourth end position P ₄ The plane coordinates of are detected. The detected plane coordinates are output to the arrangement position correction processing unit 35.
[0068]
Then, finally, in step S13, the arrangement position correction processing unit 35 inputs the first to fourth end positions P respectively input. ₁ ~ P ₄ The plane coordinates and the radius of the center of the outer circumference circle formed by the outer peripheral edge of the wafer 1 are calculated based on the above-mentioned plane coordinates. In the case where the respective plane coordinates are stored in the memory unit 31, the above-described calculation is performed by extracting the respective plane coordinates from the memory unit 31. In calculating the center and the radius of the outer circle, it is needless to say that the calculation can be performed using a general circle equation. The calculation can be performed based on the plane coordinates of at least three or more end positions. In the present embodiment, since the plane coordinates of the four end positions are detected, the plane coordinates of one of the four places are specified by the other three places due to, for example, a detection error or the like. In the case where the plane coordinates are peculiar to the outer circle, the center and the radius of the outer circle are calculated based on the plane coordinates of the other three places, ignoring the one plane coordinate. You can also. As described above, the arrangement position correction processing unit 35 corrects the plane coordinates of the arrangement position of each die 2 based on such a calculation result.
[0069]
After that, in the pickup device 101, based on the correction result of the plane coordinates of the arrangement position of each die 2, the control device 30 controls the operation of each component and holds the components on the holding table 21. From the wafer 1, the push-up operation of each die 2 by the push-up nozzle 14 is performed, and the pick-up operation of each die 2 by the suction nozzle 12 a of the pickup head 12 can be reliably performed. The control of the operation in each of the above-described steps is performed while the central processing unit 39 of the control device 30 performs integrated control.
[0070]
Next, as a method of detecting the center and the radius of the outer peripheral circle of the wafer according to the modified example of the present embodiment, the method described above is applied to a case where the wafer 1 is not a disk but a semicircle, that is, a half circle. The detection method will be described with reference to FIG.
[0071]
As shown in FIG. 7, a 配置 -circle wafer 61 attached to the wafer sheet 3 is arranged and held on the holding table 21. In detecting such an outer peripheral circle of the wafer 61, the reference position is set such that the end position of each reference image data is located at a portion where the outer peripheral end of the half-circle wafer 61 exists. This can be dealt with by adjusting the rotation angle of the image data.
[0072]
For example, in FIG. ₀ More first reference image data D ₁ Create Thereafter, the first reference image data D ₁ Is rotated counterclockwise by, for example, 45 degrees to obtain the second reference image data D ₂ Create as Further, the second reference image data D ₃ Is rotated counterclockwise by, for example, 45 degrees to obtain third reference image data D ₃ Create as The first to third reference image data D thus created ₁ ~ D ₃ And the first to third end position P ₁ ~ P ₃ Can be detected, and the plane coordinates and the radius of the center of the outer peripheral circle formed by the outer peripheral end of the half-circular wafer 61 can be calculated based on the detection result.
[0073]
Further, as a method for detecting the center and the radius of the outer peripheral circle of the wafer according to another modification of the present embodiment, the method described above is applied to a case where the wafer is not a disk, not a semicircle, and is a quarter circle. FIG. 8 shows the detection method.
[0074]
As shown in FIG. 8, even when the wafer is a quarter-circle wafer 71, the same procedure as in the case where the wafer 61 is half-circular as described above is performed. The rotation angle of the reference image data is adjusted by adjusting the rotation angle of the reference image data so that the end position of each reference image data is located at the portion where the outer peripheral end of the 1/4 circular wafer 71 exists. It is possible to calculate the center and radius of the outer peripheral circle formed by the outer peripheral end of the / 4 circular wafer 71.
[0075]
Further, as shown in FIG. 3, the respective dies 2 taken out from the diced wafer 1 are not, in principle, located near the outer peripheral end of the wafer 1 but are located near the outer peripheral end. Is a die 2 having no square shape that cannot be used as the die 2. Therefore, for example, even in a case where some of the dies 2 are already taken out of the wafer 1, the outer peripheral end of the wafer 1 is formed by the respective dies 2 having no rectangular shape. It will be in the state as formed. Therefore, even for the wafer 1 from which such partial removal of the die 2 has been performed first, an image of the outer peripheral end portion is captured and compared with the respective reference image data, and the wafer 1 Detection of the outer circumference circle can be performed. However, in this case, the reference image data D ₀ It is necessary to create the image area abcd as an area where the die 2 taken out earlier is not displayed.
[0076]
Next, the reference image data D ₀ Will be further described. Reference image data D shown in FIG. 4A used in the present embodiment. ₀ Is created based on the virtual wafer 51 having the same arc as the wafer 1. Therefore, as shown in FIG. ₀ 5, dicing lines L, which are gaps between the dies formed by dicing, are displayed. Therefore, in the image comparison, the dicing line L may be determined to be the outer peripheral edge of the wafer 1. In such a case, if the image cannot be accurately compared. Can also occur.
[0077]
In order to prevent such a problem from occurring, for example, as shown in FIG. _a When the image of the outer peripheral edge of the wafer 1 is captured by the imaging camera 10, the focal position of the imaging is shifted to capture an image in which the dicing line L of the wafer 1 is blurred. And then collating the images with each other. Further, instead of the case where the dicing line L is blurred by adjusting the focal position, the illuminance at the time of imaging is adjusted, for example, by increasing the illuminance of illumination, halation is intentionally generated. Alternatively, the dicing line L may be hardly imaged.
[0078]
In addition, reference image data D created in advance ₀ Can reduce the image area abcd within a range in which the arc formed by the outer peripheral end of the virtual wafer 51 displayed in the image area abcd can be recognized. As described above, by reducing the image area abcd, the data amount is reduced, and the reference image data D ₀ Can be easily handled.
[0079]
Also, the first reference image data D ₁ Is rotated by a predetermined angle, and the second reference image data D ₂ Is generated, the second reference image data D ₂ To rotate the third reference image data D ₃ It is preferable that, when creating the images, for example, each of the rotation angles is the same as the above-mentioned predetermined angle, and the rotation is sequentially performed by the above-mentioned predetermined angle. Further, in such a case, in consideration of detecting the outer circumferential circle of the quarter-circular wafer 71, the angle at which three end positions can be taken with a margin in the wafer 1 is defined as: The angle of each rotation is preferably at least about 30 degrees. On the other hand, in the case where the outer peripheral circle is detected in the disc-shaped wafer 1, for example, the angles are positions at which four end positions can be taken. Is preferably about 90 degrees. In particular, the merit of employing the four end positions as shown in FIG. 3 is that the wafer 1 usually has an orientation flat (a portion obtained by cutting the wafer end straight) at one of the upper, lower, left, and right sides. In many cases, the position where such an orientation flat is formed can be detected by escaping, so that calculation errors can be reduced and erroneous recognition can be prevented.
[0080]
In the present embodiment, the reference image data D stored in the memory unit 31 in advance is used. ₀ In the reference image data creation unit 33, the first to fourth reference image data D ₁ ~ D ₄ Has been described, but the present embodiment is not limited only to such a case. In place of such a case, for example, the first to fourth reference image data D ₁ ~ D ₄ Are created sequentially by the same procedure as above, that is, by sequentially rotating one piece of reference image data by a predetermined angle, and the first to fourth pieces of reference image data D created in advance are created. ₁ ~ D ₄ May be read by the control device 30.
[0081]
(Effects of Embodiment)
According to the above embodiment, the following various effects can be obtained.
[0082]
First, image data including a part of the outer peripheral edge of the virtual wafer 51 having the same arc as the wafer 1 placed on the holding table 21 of the pickup device 101 is used as the reference image data D. ₀ And the reference image data D ₀ Is rotated two-dimensionally by a predetermined angle or an angle different from the predetermined angle, so that a plurality of first to fourth reference image data D ₁ ~ D ₄ By comparing each of the created reference image data with an image partially including the outer peripheral edge of each actual wafer 1 imaged by the imaging camera 10 to obtain a plurality of edge images. The positions are the first to fourth end positions P ₁ ~ P ₄ Can be detected.
[0083]
That is, since the comparison between the image data created in advance and the actually captured image, that is, the comparison between the images is performed, for example, compared with the case where the comparison between the points is performed, Collation can be performed easily and reliably. For example, in the case where a point-to-point comparison is performed, it is detected that the points are completely coincident with each other. In the collation between the images, even if a complete match between the images is not detected, it is possible to perform the collation by detecting that the images substantially match. Therefore, the collation can be performed easily and reliably, and the plane coordinates of the respective end positions can be detected more easily and reliably.
[0084]
In addition, the detection of the plane coordinates of each of the end positions is performed by setting the first to fourth end positions P as at least three or more end positions. ₁ ~ P ₄ Are detected on the plane coordinates of the four end positions in total, and the center and radius of the outer circumference of the wafer 1 are calculated based on the detection results. The center and radius of the outer circumference can be calculated with higher accuracy than in the case where the outer circumference is specified based on the detection result of the end position of the location.
[0085]
In such a detection method, the first to fourth reference image data D are used as the plurality of reference image data. ₁ ~ D ₄ Are used, and these are one of the previously created reference image data D ₀ On the basis of the above, the reference image data creation unit 33 of the control device 30 sequentially creates reference image data different from each other sequentially by rotating in a plane at a predetermined angle or an angle different from the predetermined angle. Therefore, there is no need to prepare each reference image data in advance. Further, the one reference image data D ₀ To the first reference image data D ₁ Is created, and the first reference image data D ₁ Is rotated by a predetermined angle to obtain the second reference image data D ₂ As described above, since the respective reference image data are sequentially created, the data capacity of the image data handled by the control device 30 can be reduced. This makes it possible to improve the processing speed in detecting the outer circumference of the wafer 1.
[0086]
Also, the reference image data D ₀ Can be rotated by a desired angle to create respective reference image data in sequence, so that, other than the disk-shaped wafer 1, the half-shaped wafer 61 and the quarter-shaped wafer 71 can be used. The present detection method can be applied to a wafer having a partially circular shape, and a method for detecting the center and radius of the outer peripheral circle of the wafer that can handle wafers in various states can be provided. Further, if attention is paid to the fact that the die 2 having no square shape located near the outer peripheral end of the wafer 1 is not taken out, the wafer 1 from which the die 2 has been taken out earlier is partially obtained. Also, the present detection method can be applied.
[0087]
Note that by appropriately combining any of the various embodiments described above, the effects of the respective embodiments can be achieved.
[0088]
【The invention's effect】
According to the first aspect or the second aspect of the present invention, image data including a part of the outer peripheral end of a virtual wafer having the same arc as the diced wafer is used as the reference image data. Is rotated in a plane by a predetermined angle or an angle different from the predetermined angle, thereby generating first to third reference image data as a plurality of mutually different reference image data. By performing a comparison between the reference image data and the captured image of the actual part of the outer peripheral edge of the wafer, a plurality of edge positions at the outer peripheral edge of the wafer are defined as first to fourth positions. The plane coordinates of the end position of No. 3 can be detected.
[0089]
That is, since the previously created reference image data is compared with the actually captured image, that is, the images are compared with each other, for example, compared with the case where the points are compared with each other. Thus, the above-mentioned collation can be performed easily and reliably. Specifically, in a case where a point-to-point comparison is performed, it is determined that the points are completely matched by detecting that the points are completely coincident with each other. Therefore, in the collation between images, even when perfect coincidence between images is not detected, the collation can be performed with detection of a degree of almost coincidence. Therefore, the collation can be performed easily and reliably, and the plane coordinates of the respective end positions can be detected more easily and reliably.
[0090]
The detection of the plane coordinates of each of the end positions is performed by detecting the plane coordinates of a total of three end positions of the first to third end positions as at least three or more end positions. Since the center and diameter of the outer circumference of the wafer are calculated based on the detection result, for example, as in the conventional detection method, the outer circumference is determined based on the detection results of the two end positions. The center and the diameter of the outer circumferential circle can be calculated with higher accuracy than in the case where the above is specified.
[0091]
In addition, the first to third reference image data are used as the reference image data. These are based on one piece of the reference image data created in advance, and have a predetermined angle or a predetermined angle, respectively. Since it is created by being rotated by a different angle in a plane, there is no need to create respective reference image data different from each other in advance, and the center of the outer peripheral circle of the wafer and the center can be more easily obtained. Calculation of the diameter can be performed.
[0092]
According to the third aspect of the present invention, the comparison between each of the reference image data and each of the captured images is performed by comparing all or a part of the outer peripheral edge of the wafer in the captured images with the Since the entire peripheral edge of the virtual wafer in the reference image data is performed by detecting a matching position, the collation can be reliably performed, and the calculation of the center and radius of the peripheral circle can be reliably performed. It can be carried out.
[0093]
According to the fourth aspect of the present invention, as a method of creating the third reference image data, the second reference image data created by rotating the first reference image data by the predetermined angle is provided. The image data further rotated can be created as the third reference image data. That is, by sequentially rotating the created reference image data, a plurality of different reference image data can be created. Therefore, the data volume of image data handled in detecting the center and diameter of the outer peripheral circle of the wafer can be reduced, and the processing speed in the detection can be improved.
[0094]
According to the fifth aspect of the present invention, each image of the outer peripheral end of the wafer imaged with the imaging focus position shifted so that the dicing line of the wafer is blurred, and the dicing line is displayed. By performing the comparison with each of the reference image data that has not been performed, it is possible to prevent a detection error due to the reading of the dicing line on the wafer that has been subjected to the dicing, and to perform more reliable detection.
[0095]
According to the sixth aspect of the present invention, even when the wafer is a half circular or quarter circular partial circular wafer, the rotation angle of the reference image data can be obtained. By adjusting the position, the respective end positions at the outer peripheral end of the wafer can be detected. Therefore, it becomes possible to calculate the center and the diameter of the outer peripheral circle even for the partial circular wafer which could not be applied conventionally.
[0096]
According to the seventh aspect of the present invention, in the control device for controlling the operation of each component of the semiconductor chip pickup device, one of the outer peripheral end portions of the virtual wafer having the same shape as the previously created wafer is provided. A reference image data creating unit that creates first to third reference image data based on the reference image data including the unit, an image of an outer peripheral end of the wafer captured by an imaging device, An end position detection unit that performs comparison with first to third reference image data and detects plane coordinates along the surface of the wafer at respective end positions that match each other, and plane coordinates of the respective end positions And calculating the plane coordinates of the center of the outer peripheral circle of the wafer and the diameter thereof based on the above, and correcting the plane coordinates at the arrangement positions of the respective semiconductor chips based on the calculation result. By being provided with the location correction processing unit, it is possible to calculate the center and diameter of the outer circumference of the wafer that can achieve the same effects as according to the first aspect or the second aspect. Therefore, the plane coordinates of the arrangement position of each of the semiconductor chips are accurately recognized based on such a highly accurate calculation result, and a semiconductor chip pickup device capable of performing a reliable semiconductor chip pickup operation. Can be provided.
[0097]
According to the eighth aspect of the present invention, in the reference image data creating section, the first reference image data is rotated by the predetermined angle as means for creating the third reference image data. The rotated second reference image data can be further created as the third reference image data. That is, by sequentially rotating the created reference image data, a plurality of different reference image data can be created. Accordingly, it is possible to provide a semiconductor chip pickup device which can reduce the data capacity of image data handled in the detection of the center and diameter of the outer peripheral circle of the wafer, and can improve the processing speed in the detection. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing a schematic configuration of a pickup device according to an embodiment of the present invention.
FIG. 2 is a partially enlarged schematic view of a wafer plate in the pickup device.
FIG. 3 is a schematic plan view of a wafer held by the pickup device.
4A and 4B are reference image data used for detecting the outer circumference of the wafer, wherein FIG. 4A is reference image data displaying a dicing line of a virtual wafer, and FIG. 4B is a dicing line of the virtual wafer; Are reference image data not displayed.
FIG. 5 is a flowchart showing a procedure for detecting the center and radius of the outer peripheral circle of the wafer.
FIG. 6 is a block diagram showing a main configuration of a control device in the pickup device.
FIG. 7 is a schematic plan view of a half-circle wafer held by the pickup device.
FIG. 8 is a schematic plan view of a quarter-circle wafer held by the pickup device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Die, 3 ... Wafer sheet, 4 ... Wafer plate, 4a ... Hollow hole part, 10 ... Imaging camera, 11 ... Imaging camera moving device, 12 ... Pickup head, 13 ... Pickup head moving device, 14 ... Push-up nozzle, 15 Push-up nozzle moving device, 20 wafer holding unit, 21 holding table, 21a upper surface, 21b hollow hole, 22 Y-axis direction moving device, 30 controller, 31 memory unit, 32 ... Control unit, 33 ... Reference image data creation unit, 34 ... End position detection unit, 35 ... Arrangement position correction processing unit, 36 ... Imaging control unit, 37 ... X-axis direction movement control unit, 38 ... Y-axis direction movement control Unit, 39 central processing unit, 40 pickup control unit, 51 virtual wafer, 61 half-circle wafer, 71 quarter-wafer, 101 pickup device, Ow Center of E Ha, Ot ... the center of the holding table, D ₀ And D _a ... Reference image data, D ₁ ~ D ₄ ... first to fourth reference image data, P ₁ ~ P ₄ ... first to fourth end positions, abcd ... image area, L ... dicing line.

Claims (8)

In the method of detecting the center of a wafer (1, 61, 71) diced so that a plurality of semiconductor chips (2) are arranged in a grid,
First reference image data (D ₁ ) including a part of the outer peripheral edge of the virtual wafer (51) having the same arc as the previously created wafer, and a captured image of the outer peripheral edge of the wafer. , And a position that matches each other is detected as a _first end position (P ₁ ),
The second reference image data (D ₂ ) obtained by rotating the first reference image data by a predetermined angle is compared with an image taken of the outer peripheral edge of the wafer, and a position matching each other is determined. 2 as the end position (P ₂ ),
The third reference image data (D ₃ ) in which the first reference image data is rotated by an angle different from the predetermined angle is compared with a captured image of the outer peripheral edge of the wafer, and the first and second reference image data coincide with each other. Is detected as a _third end position (P ₃ ),
The plane of the center of the outer circumference formed by the outer peripheral edge of the wafer based on the planar coordinates along the surface of the wafer from the detected first end position to the third end position. A method of detecting a center of a wafer, comprising calculating coordinates and a diameter thereof. In a semiconductor chip pickup method for picking up semiconductor chips from a wafer (1, 61, 71) diced so that a plurality of semiconductor chips (2) are arranged in a lattice pattern,
The reference image data (D ₀ ) including a part of the outer peripheral end of the virtual wafer (51) having the same arc as the previously created wafer is read out and used as first reference image data (D ₁ ). An image of the outer peripheral edge of the wafer is captured, the captured image is compared with the first reference image data, and a position that matches each other is detected as a _first edge position (P ₁ ). ,
The first reference image data rotated by a predetermined angle is used as second reference image data (D ₂ ), and an image of the outer peripheral edge of the wafer is captured. 2 is compared with the reference image data, a position that matches each other is detected as a _second end position (P ₂ ),
The first reference image data rotated by an angle different from the predetermined angle is used as third reference image data (D ₃ ), and an image of the outer peripheral end of the wafer is captured. By comparing the image with the third reference image data, a position that matches each other is detected as a _third end position (P ₃ ),
The plane of the center of the outer circumference formed by the outer peripheral edge of the wafer based on the planar coordinates along the surface of the wafer from the detected first end position to the third end position. Calculate the coordinates and their diameter,
A semiconductor chip pick-up method for correcting the plane coordinates at the arrangement position of each of the semiconductor chips based on the calculation result and picking up each of the semiconductor chips. The comparison between each of the reference image data and each of the captured images is performed by comparing all or a part of the outer peripheral edge of the wafer in the captured image with the outer peripheral edge of the virtual wafer in the reference image data. 3. The method for picking up a semiconductor chip according to claim 2, wherein all of the steps are performed by detecting a matching position. 4. The semiconductor chip pickup method according to claim 2, wherein the third reference image data is created by rotating the second reference image data. The reference image data is image data created so as not to display a dicing line (L) on the virtual wafer,
Verification of each image of the outer peripheral edge of the wafer imaged with the focus position of the imaging shifted so that the dicing line of the wafer is blurred, and respective reference image data in which the dicing line is not displayed The method for picking up a semiconductor chip according to claim 2, wherein the method is performed. The semiconductor chip pickup according to claim 2, wherein a partially circular wafer whose outer peripheral edge forms a part of the outer peripheral circle is used as the wafer. 7. Method. From a holding table (21) on which wafers (1, 61, 71) diced so that a plurality of semiconductor chips (2) are arranged in a lattice pattern, the respective semiconductor chips are picked up by a pickup head (12). ), A semiconductor chip pickup device (101)
An imaging device (10) for capturing an image of the surface of the wafer;
Moving devices (11 and 22) for relatively moving the imaging device and the holding table along the surface of the wafer;
A control device (30) for controlling the operation of the imaging device and the moving device,
The control device includes:
Based on the reference image data (D ₀ ) including a part of the outer peripheral end of the virtual wafer (51) having the same arc as the previously created wafer, the reference image data is converted to the first reference image data (D ₁ ), the first reference image data rotated by a predetermined angle is generated as second reference image data (D ₂ ), and the first reference image data rotated by an angle different from the predetermined angle is generated. A reference image data creation unit (33) for creating the reference image data as _third reference image data (D ₃ );
By controlling the moving device and the imaging device, while performing the relative movement by the moving device, the image of the outer peripheral end of the wafer imaged by the imaging device, and from the first reference image data The third reference image data is compared with the respective reference image data, and plane coordinates along the surface of the wafer at respective end positions (P ₁ , P ₂ , P ₃ ) that match each other are detected. An end position detection unit (34);
The plane coordinates and the diameter of the center of an outer peripheral circle formed by the outer peripheral end of the wafer are calculated based on the plane coordinates of the respective end positions, and the respective semiconductor chips are calculated based on the calculation results. A semiconductor chip pickup device comprising: an arrangement position correction processing unit (35) for correcting the plane coordinates at the arrangement position. 8. The semiconductor chip pickup device according to claim 7, wherein the reference image data creation unit creates the third reference image data by rotating the second reference image data.

Images