JPH08236995A - Method of mounting chip - Google Patents

Abstract

PURPOSE: To eliminate lowering of mounting precision caused by change of a relative position of a head and a camera due to thermal expansion of a holder wherein a head and a camera are built integrally which is caused by heat generation of a motor for moving a nozzle up and down. CONSTITUTION: Misalignment of a nozzle 2 due to thermal expansion of a holder 3 caused by heat generation of a motor 5 which drives a head is detected by a camera 19 for chip recognition. The misalignment is found by observing a mark 18 formed in a specified position by a camera 4 for substrate recognition. Thereafter, a chip 10 is transferred and mounted on a substrate 15 while movement stroke of a head is corrected based on the determined misalignment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip mounting method for automatically mounting a chip at a predetermined position on a substrate.

[0002]

2. Description of the Related Art Various chips (electronic parts) such as ICs, LSIs, flip chips, resistance chips, and chip capacitors are mounted at predetermined positions on a board by an electronic parts mounting device. The electronic component mounting apparatus includes a head having a nozzle for vacuum suctioning the chip, and the chip provided in the parts feeder is mounted on the substrate while horizontally moving the head in the X direction and the Y direction. .

A chip mounting method using a conventional electronic component mounting apparatus will be described below. FIG. 13 is a side view of a conventional electronic component mounting apparatus, and FIG. 14 is a recognition image view of the same mark.
In FIG. 13, reference numeral 1 is a head, which includes a nozzle 2. The head 1 is held by the holder 3. Holder 3
The head 1 and the camera 4 for recognizing the substrate are integrally assembled to the. Reference numeral 5 denotes a motor mounted on the holder 3, and when the motor 5 is driven, the nozzle 2 moves up and down. A transmission system such as a pulley and a belt for vertically moving the nozzle 2 is omitted.

A Y table 6 is provided with a Y direction feed screw 7. A nut 8 is coupled to the upper portion of the holder 3, and the nut 8 is screwed onto the feed screw 7. Therefore, when the Y motor 9 is driven and the feed screw 7 rotates, the holder 3 moves in the Y direction along the feed screw 7.
An X table 11 is provided with a feed screw 12 in the X direction. The X table 11 and the Y table 6 are connected orthogonally to each other. Therefore, when the X motor 13 is driven and the feed screw 12 rotates, the Y table 6 moves in the X direction along the feed screw 12, whereby the holder 3 also moves in the X direction.
Move in the direction. That is, the Y table 6 and the X table 11 integrally integrate the head 1 and the board recognition camera 4 into the X table.
It is a moving device for moving horizontally in the Y direction.

Reference numeral 15 is a substrate. The substrate 15 is conveyed in the X direction by the conveyor 17 along the guide rails 16. A mark 18 is formed at an appropriate place such as on the guide rail 16. A camera 19 for chip recognition is installed on the side of the guide rail 16. The chip recognition camera 19 includes a chip 10 that is vacuum-adsorbed by the nozzle 2.
Is observed from below and its position is detected. Reference numeral 20 denotes a parts feeder, which is installed beside the guide rail 16. As the parts feeder 20, a tape feeder, a tube feeder, etc. are often used. The parts feeder 20 is equipped with various types of chips 10.

A control unit 21 controls the drive circuit 23 and the image recognition circuit 24 while reading various data such as program data registered in the storage unit 22 and data relating to the chip 10. The drive circuit 23 drives the motor 5, the Y motor 9, and the X motor 13. The image recognition circuit 24 also recognizes the image data captured by the camera 4 for board recognition and the camera 19 for chip recognition.

This conventional electronic component mounting apparatus is constructed as described above. Next, a chip mounting method will be described. Prior to transferring and mounting the chip 10 mounted on the parts feeder 20 on the substrate 15, the position of the nozzle 2 is first recognized as follows. That is, the head 1
Initially it is at the origin O position, and drives the motor 9 there,
The board recognizing camera 4 moves the mark 18 to a position where it is expected to come into the visual field. The moving distances from the origin O position at this time are X1 and Y1.

Next, the mark 18 is formed on the board recognition camera 4.
To observe. FIG. 14 shows an image of the visual field of the camera 4 for board recognition at this time. In FIG. 14, the black-painted image is the image of the mark 18 at this time, and the coordinate system (X, Y) set in the visual field of the camera 4 for board recognition.
The coordinates of the initial position of the image of the mark 18 at (MX
0, MY0). Here, the positional relationship between the nozzle 2 and the board recognition camera 4 (distance between the two) is constant (known), and the initial position of the mark 18 is confirmed by the board recognition camera 4 as described above. The position of the nozzle 2 has also been confirmed.

When the initial position of the nozzle 2 is confirmed by observing the mark 18 with the substrate recognition camera 4 as described above, a substrate recognition mark (not shown) formed on the substrate 15 Is observed by the board recognition camera 4 to recognize the position of the board 15, and then the board 1 of the chip 10 is recognized.
Start implementation in 5. That is, in FIG. 13, the X motor 13 and the Y motor 9 are driven to move the nozzle 2 above the parts feeder 20, and the motor 5 is driven there to cause the nozzle 2 to move up and down. The chip 10 provided in the parts feeder 20 is vacuum-sucked and picked up.

Next, the nozzle 2 is moved above the chip recognition camera 19 as shown in FIG. 13, and the chip 10 vacuum-adsorbed by the nozzle 2 is observed by the chip recognition camera 19, and the position of the chip 10 is determined. To recognize. Then, based on the recognition result and the position of the substrate 15 recognized, the nozzle 2 is moved in the X direction or the Y direction by a predetermined distance, and the nozzle 2 is moved up and down there to move the chip 10 to the substrate 15
It is mounted at the predetermined coordinate position of. By repeating the above operation, the chip 10 of the parts feeder 20 is transferred to the substrate 15
Will be installed one after another.

By the way, while mounting the chip 10 of the parts feeder 20 on the substrate 15 as described above, the holder 3 is thermally expanded by the heat generated by the motor 5, and as a result, the position of the camera 4 for recognizing the substrate is changed. Change. Since the position of the mounting position of the chip 10 is recognized based on the observation result of the camera 4 for recognizing the substrate, this change appears as a displacement of the mounting position of the chip 10 on the substrate 15, and the chip 10
Since the mounting accuracy of the substrate on the substrate 15 is reduced, it is necessary to correct it. Therefore, a conventional correction method based on this thermal expansion will be described next.

That is, the camera 4 for board recognition is set to the origin 0.
The mark 18 is moved again from the position to the above-mentioned movement distances X1 and Y1 and the mark 18 is observed again by the board recognition camera 4. In FIG. 14, the white image is the image of the mark 18 at this time. Therefore, the position of this image (MX1, M
Y1) is calculated and relative deviations ΔX1 and ΔY1 from the initial position (MX0, MY0) are calculated. This deviation ΔX1, ΔY
1 is caused by a positional change of the camera 4 for recognizing the substrate due to the thermal expansion of the holder 3.

When the deviations ΔX1 and ΔY1 are obtained in this way, the mounting of the chip 10 on the substrate 15 is restarted, but in this case, the movement of the nozzle 2 in the X and Y directions by the driving of the motors 13 and 9. By subtracting the deviations ΔX1 and ΔY1 from the amount, the chip 10 is mounted on the substrate 15 while correcting the deviations ΔX1 and ΔY1. Deviation Δ
The detection of X1 and ΔY1 is appropriately performed (for example, every time 100 chips 10 are mounted on the substrate 15).

[0014]

However, the conventional chip mounting method described above has the following problems.
That is, the above conventional method is based on the premise that the relative positional relationship between the nozzle 2 and the board recognition camera 4 (the distance between the nozzle 2 and the board recognition camera 4) is constant. However, in reality, the holder 3 caused by the heat generation of the motor 5
Due to the thermal expansion of No. 2, the positional relationship between the nozzle 2 and the camera 4 for recognizing the substrate changes. However, in the above-mentioned conventional method, since this change is not taken into consideration, there is a problem in that the mounting accuracy is lowered due to the thermal expansion of the holder 3. In particular, in recent years, the required mounting accuracy of the chip tends to become strict, so that the deterioration of the mounting accuracy due to the thermal expansion of the holder 3 cannot be ignored.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a chip mounting method capable of eliminating a decrease in chip mounting accuracy due to thermal expansion of a holder in which a head and a board recognition camera are integrally assembled.

[0016]

To this end, according to the present invention, a camera for chip recognition detects a displacement of a nozzle due to thermal expansion of a holder due to heat generation of a motor for driving a head, and a camera for substrate recognition by thermal expansion. The position shift of the chip is detected by observing the mark at a predetermined position with this camera for board recognition, and the chip is transferred and mounted on the board while correcting the moving stroke of the head based on the detected position shift. It is the one.

[0017]

According to the above structure, the nozzle for chip recognition detects the positional deviation of the nozzle, and the camera for board recognition detects the positional deviation of the camera itself for board recognition. The misalignment is a misalignment of the relative positional relationship between the nozzle and the substrate recognition camera due to thermal expansion of the holder. Therefore, the chip is mounted while correcting the movement stroke of the head in consideration of the two positional deviations.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view of an electronic component mounting apparatus according to a first embodiment of the present invention, FIG. 2 is a flowchart of the initial setting process, FIG. 3 is a flowchart of the nozzle position correcting process, FIG. 4 is a recognition image diagram of the mark, FIG. 5 is a recognition image diagram of the nozzle. Since the electronic component mounting apparatus shown in FIG. 1 is the same as the conventional example shown in FIG. 13, its description is omitted.

First, referring to the flow chart of FIG.
The initial setting process will be described. First, in FIG.
The head 1 is moved from the origin O position to the position X1, where the mark 18 is expected to enter the visual field of the board recognition camera 4.
Y1 is moved (step 1). In this state, as shown in FIG. 1, the mark 18 enters the visual field of the camera 4 for board recognition. Therefore, the mark 18 is observed by the board recognizing camera 4 (step 2), and the initial position (see FIG.
Initial position of the mark 18 indicated by a black circle (MY0, M
(See Y0)) is detected (step 3), and the data is stored in the storage unit 22 (step 4). FIG. 4 shows an image at this time, and FIG. 4 is the same as FIG. The operations of steps 1 to 4 described above are the same as those of the conventional method described above.

Next, the nozzle 2 is a camera 1 for chip recognition.
The head 1 is moved a distance X2, Y2 from the origin 0 in the X and Y directions to a position where it is expected to enter the visual field 9 (step 5). Therefore, the nozzle 2 is lowered (step 6), the nozzle 2 is observed with the camera 19 for chip recognition (step 7), and the initial position of the nozzle 2 (NX0, NY).
0) is detected (step 8), and the data is stored in the storage unit 22.
(Step 9). FIG. 5 is an image at this time.

After the initial setting process is completed as described above, the chip 10 of the parts feeder 20 is then mounted on the substrate 15. This mounting method is the same as that of the conventional example described above, and therefore its explanation is omitted.

As described above, while the chip 10 is mounted on the substrate 15, the holder 3 is thermally expanded by the heat generated by the motor 5, and the positions of the camera 4 for recognizing the substrate and the nozzle 2 of the head 1 change. Therefore, next, a method of correcting the positional deviation of the mounting position of the chip caused by the positional deviation of the nozzle 2 due to the thermal expansion will be described with reference to the flowchart of FIG.

First, the head 1 is moved from the origin 0 by X1 and Y1 in the X and Y directions (step 11), and the mark 18 is observed by the camera 4 for recognizing the substrate (step 1).
2), the position of the mark 18 in the image recognition circuit 24 (the coordinate position of the mark 18 shown in white in FIG. 4 (MX1, M
(See Y1)) is detected (step 13). Next, the control unit 21 causes the mark 18 shown in FIG.
1, ΔY1 is obtained (step 14). This ΔX1, Δ
Y1 is a camera 4 for recognizing the substrate due to thermal expansion of the holder 3.
Of the initial position of the mark 18 (MX0, MX0,
MY0).

Next, the head 1 is moved from the origin 0 (X2, Y2).
It is moved to a distant position, that is, above the camera 19 for chip recognition (step 15), the nozzle 2 is lowered there (step 16), and the nozzle 2 is observed by the camera 19 for chip recognition (step 17) to perform image recognition. The circuit 24 detects the position of the nozzle 2 (see the coordinate position (NX1, NY1) of the nozzle 2 shown by white in FIG. 5) (step 18). FIG. 5 shows an image at this time, and the nozzle 2
The position deviation ΔX2, ΔY2 of the nozzle 2 is obtained by the control unit 21 from the difference between the initial position (NX0, NY0) of the nozzle 2 (step 19). Next, the controller 21 calculates the correction values ΔX and ΔY according to the following equations.
Is calculated (step 20).

ΔX = ΔX1 + ΔX2 ΔY = ΔY1 + ΔY2 Next, these ΔX and ΔY are stored in the storage unit 22 (step 21). The correction values ΔX and ΔY are positional deviation amounts in the relative positional relationship between the camera 4 for recognizing the substrate and the nozzle 2 due to the thermal expansion of the holder 3.

When the correction values ΔX and ΔY are obtained as described above, the mounting of the chip 10 on the substrate 15 is restarted. When mounting the chip 10 thereafter, the above correction values are calculated from the moving stroke of the head 1. If the correction is performed by subtracting ΔX and ΔY, the chip 10 is mounted while correcting the positional deviation of the head 1 due to the thermal expansion of the holder 3, and high mounting accuracy can be secured.

Next, a second embodiment of the present invention will be described. Figure 6
Is a side view of the electronic component mounting apparatus of the second embodiment of the present invention, FIG. 7 is a perspective view of the same part, FIG. 8 is a flowchart of the same initial setting step, FIG. 9 is a flowchart of the same nozzle position correcting step, and FIG. FIG. 11 is a recognition image view of the same mark, FIG. 11 is a recognition image view of the same nozzle, and FIG. 12 is a view image of a mark by a camera for recognizing the same chip.

The second embodiment differs from the first embodiment in the mark recognition structure. That is, in FIGS. 6 and 7, 30 is a mark unit, which is configured as follows. Reference numeral 31 is a main body box, to which a cylinder 32 is attached by a bracket 37. The rod 33 of the cylinder 32 is positioned horizontally on the upper surface of the main body box 31, a slider 35 is coupled to the tip of the rod 33, and a transparent plate 34 is coupled to the slider 35. The mark 18 is formed on the plate 34. Reference numeral 36 is a guide rail for guiding the sliding of the slider 35. Therefore, when the rod 33 of the cylinder 32 projects forward, the plate 34 projects above the camera 19 for chip recognition, as shown by the chain line in FIG. 6 and FIG. 7.
The mark 18 can be observed by the camera 19 for chip recognition. Further, when the rod 33 of the cylinder 32 is retracted, the plate 34 retreats from above the camera 19 for chip recognition. That is, this chip recognition camera 19
Recognizes the chip 10 and the mark 18.

Next, the initial setting process will be described with reference to FIG. In FIG. 8, the same steps as those in FIG. 2 are given the same step numbers. First, prior to performing the operation of step 1, the rod 33 of the cylinder 32 is projected to project the plate 34 onto the camera 19 for chip recognition, and the mark 18 is positioned in the visual field of the camera 19 for chip recognition. (Step 0). Steps 1 to 4 are the same as steps 1 to 4 in FIG. 2, and description thereof will be omitted.

Camera 1 for chip recognition in step 4-1
The mark 18 is observed at 9 and the initial position (MCX0, MCY0) is detected by the image recognition circuit 24 at step 4-2.
In step 4-3, the data is stored in the storage unit 22.
As shown in FIG. 12, the protrusion amount of the plate 34 is adjusted so that the mark 18 (black circle) is located at the center of the visual field of the camera 19 for chip recognition. In this way, the initial position of the mark 18 as seen from the chip recognition camera 19 (M
If CX0, MCY0) is recognized, step 4-4
The rod 33 of the cylinder 32 with the plate 35
Is removed from the camera 19 for chip recognition. Next, the operations of steps 5 to 9 are performed, but since these steps 5 to 9 are the same as steps 5 to 9 in FIG. 2, the description thereof will be omitted.

Next, the nozzle position correcting process will be described with reference to FIG. Steps 11 to 13 and steps 15 to 21 of the second embodiment are the same as those of the first embodiment shown in FIG. First, before performing step 11, the plate 34 is projected above the camera 19 for chip recognition (step 10). Then, in step 13-1, the mark recognition camera 19 marks 18
The position of the mark 18 (MC
X1, MCY1) is detected.

As shown in FIG. 12, in the initial setting process,
Mark 18 (black circle) at the center of camera 19 for chip recognition
However, in the nozzle position correction process, the mark 18 (white circle) is projected at a position displaced by (ΔX3, ΔY3). This is a positional deviation due to variations in the operation of the cylinder 32, but an accurate positional deviation (ΔX1, ΔY1) of the board recognition camera 4 cannot be obtained unless this positional deviation is taken into consideration. Therefore, in step 14, the positional deviation (ΔX1, ΔY1) of the board recognition camera 4 is obtained from the following equation.

ΔX1 = MX1-MX0 + MCX1-MCX0 ΔY1 = MY1-MY0 + MCY1-MCY0 Next, in step 14-1, the plate 34 is withdrawn from the camera 19 for chip recognition, and the correction value ΔX is obtained in the same manner as in the first embodiment. , ΔY is calculated and stored in the storage unit 22. As is clear from each of the above embodiments, the nozzle 2 and the mark 18
There are various specific means for observing.

[0034]

As described above, according to the present invention, the deterioration of the mounting accuracy due to the thermal expansion of the holder can be eliminated, and the chip can be mounted on the substrate with high positional accuracy.

[Brief description of drawings]

FIG. 1 is a side view of an electronic component mounting apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart of an initial setting process of the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 3 is a flowchart of a nozzle position correction process of the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 4 is a recognition image diagram of a mark of the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 5 is a recognition image diagram of a nozzle of the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 6 is a side view of the electronic component mounting apparatus according to the second embodiment of the present invention.

FIG. 7 is a perspective view of essential parts of an electronic component mounting apparatus according to a second embodiment of the present invention.

FIG. 8 is a flowchart of an initial setting process of the electronic component mounting apparatus according to the second embodiment of the present invention.

FIG. 9 is a flowchart of a nozzle position correction process of the electronic component mounting apparatus according to the second embodiment of the present invention.

FIG. 10 is a recognition image diagram of a mark of the electronic component mounting apparatus according to the second embodiment of the present invention.

FIG. 11 is a recognition image diagram of a nozzle of the electronic component mounting apparatus according to the second embodiment of the present invention.

FIG. 12 is an image view of a mark by a camera for chip recognition of the electronic component mounting apparatus of the second embodiment of the present invention.

FIG. 13 is a side view of a conventional electronic component mounting apparatus.

FIG. 14 is a recognition image diagram of a mark of a conventional electronic component mounting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 head 2 nozzle 3 holder 4 camera for board recognition 5 motor 6 Y table 10 chip 11 X table 15 board 19 camera for chip recognition 20 parts feeder 21 controller

Claims (1)

[Claims] 1. A holder in which a head and a camera for recognizing a substrate are integrally assembled is moved in the horizontal direction, and a chip provided in a parts feeder is vacuum-adsorbed by a nozzle provided in the head to be picked up, A chip mounting method in which a chip for adsorbing to this nozzle is observed by a camera for chip recognition and then this chip is transferred and mounted on a substrate, wherein thermal expansion of said holder is accompanied by heat generation of a motor for driving said head. The displacement of the nozzle due to is detected by the camera for chip recognition, the displacement of the camera for substrate recognition due to the thermal expansion is detected by observing a mark at a predetermined position with the camera for substrate recognition, It is possible to transfer and mount the chip on the substrate while correcting the moving stroke of the head based on the detected positional deviation. Chip mounting method of the butterflies.