JPH071771B2 - Bonding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of detecting a rotation center position of a bonding stage on which a bonding target is mounted, when the bonding stage is rotated. The present invention relates to a bonding apparatus that is performed in a specific manner.

[Conventional technology]

Conventionally, in a wedge bonding apparatus or the like, the rotation center position of the bonding stage on which the bonding target is fixed is detected by the IC on the IC case 61 adsorbed by the bonding stage 54 as shown in FIG. Case
The characteristic point 63 (for example, the corner of the bonding pad) of the IC chip 62 of 61 is used as a mark, and the operator looks at the screen of the monitor as shown in FIG. Cross line on monitor as shown in
The position (x ₁ , y ₁ ) of the mark 63 is detected from the amount of rotation of the motor of the xy table 58 at that time by aligning with the center point 65 of
The data is stored in the memory of the bonding controller 55 shown in FIG. 4, then the bonding stage is rotated 180 ° as shown in FIG. 5 (b), and the center point 65 of the cross line 64 on the monitor is again measured. Is aligned with the mark 63, the position (x ₂ , y ₂ ) of the mark 63 is detected from the rotation amount of the motor of the xy table 58, and the data is also stored in the bonding control device 55 shown in FIG. Then, from the position data (x ₁ , y ₁ ) and (x ₂ , y ₂ ), the rotation center position (x
_c , y _c ) was _calculated as x _c = (x ₁ + x ₂ ) / 2, y _c = (y ₁ + y ₂ ) / 2. The worker should interrupt the automatic bonding work to detect the rotation center position of the bonding stage, and perform the bonding while correcting the rotation center position.

[Problems to be solved by the invention]

In the conventional bonding method described above, in order to correct the rotation center position of the bonding stage, an operator looks at the monitor and adjusts the center point of the cross line on the monitor to one point on the chip so that the xy point of the camera is adjusted. Since the stage had to be operated with a manipulator, there were individual differences in the input data, and the work required nearly 20 seconds. Furthermore, even if the data of the rotation center position of the bonding stage is once input, the rotation center position itself sometimes changes due to the heat generation of the motor during the bonding work and the thermal expansion of the metal parts due to the temperature change of the outside air. Therefore, there has been a drawback that the bonding work must be stopped at a certain time interval and the worker must correct the rotation center position of the bonding stage.

In the conventional bonding method described above, the operator detects the rotational center position of the bonding stage by operating the xy stage of the camera with the manipulator, while the present invention is directed to the bonding target on the bonding stage. The image data of a certain area centered on the reference point on the monitor is input to the image processing apparatus in advance, and the image processing apparatus is used as a reference. The difference is that the detection of the rotational center position of the bonding stage is automated by using the processing device and the control device that controls the operations of the bonding stage and the camera.

[Means for Solving Problems] FIG. 1 shows the configuration of an apparatus using the bonding method of the present invention. The bonding stage 1 capable of rotating,
Camera 6 that captures the image of the upper surface of the bonding stage
And a bonding control device 3 for controlling these operations
And a mark position data storage device for storing position data for moving the bonding stage 1 and the camera 6 so that a reference point previously determined when the rotation center position of the bonding stage is detected is displayed on the monitor.
12, a rotation center position data storage device 13 for storing the corrected rotation center position of the bonding stage, and an image processing device 2. The image processing device 2 stores the image data of the area centered on the position of the reference point, the first image data storage device 10 and the second image data storage device 11, the input image from the camera and the storage. Deviation amount detecting device 4 for detecting the amount of deviation from the image data
And a computing device 5 for calculating the rotation center position of the bonding stage based on the detection result.

〔Example〕

Next, the present invention will be described with reference to the drawings. FIG. 2 (a) is a schematic view of a wedge bonding apparatus using the bonding method and apparatus according to one embodiment of the present invention. Above the bonding stage 14, the bonding head 23
There is a camera 19 attached. The bonding stage 14 and the bonding head 23 can be rotated and moved in the x-direction and the y-direction by a driving device for the θ-axis motor 20, the x-axis motor 21, and the y-axis motor 22, respectively. It is determined by the motor controller 18 and the xy-axis motor controller 17. The drive system of the bonding stage 14 and the bonding head 23 is controlled by the bonding control device 16, and the bonding control device 16 has a memory for storing mark position data, bonding stage rotation center position data, and the like. Image processing device
15 processes the image captured by the camera 19, detects the rotation center position of the bonding stage, and sends the data to the bonding control device 16. An IC case 24 in which an IC chip 25 is mounted on the bonding stage 14 is held by a fixing device (not shown) such as vacuum suction. Before the bonding work, input the following data. First, as shown in FIG. 2 (b), the θ-axis motor 20 of the bonding stage is aligned with the θ-direction origin, and the features on the IC chip are observed while looking at the screen of the monitor (not shown) that displays the image captured by the camera 19. The camera 19 is moved with a certain point 26 (a corner of the bonding pad) as a mark, and as shown in FIG. 2 (d), the camera 19 is moved to the point 26 with the center point 29 of the cross line 27 on the monitor as a mark. The image in the window 28 is stored as the first image data 30, and the x-axis motor 21
And the position (x ₁ , y ₁ ) of the point 26, which is a mark, is detected from the rotation amount of the y-axis motor 22 and stored as position data. Next, as shown in FIG. 2 (c), the bonding stage is rotated 180 °, the camera 19 is moved, and FIG.
As shown in, the center point 29 of the cross line 27 on the monitor is made to overlap the point 26 on the IC chip, which is the mark again, and it is stored as the image data 31 in the window 28 of the monitor, and further set as the mark. , The position of point 26 on the IC chip (x ₂ , y
₂ ) is stored as position data. First image data 30
The second image data 31 is theoretically an image obtained by rotating the other by 180 ° around the position of the point 26 on the IC chip as a mark. However, depending on the illumination state, in the binarized image or the like, the first image data 30 and the second image data 31 are not images obtained by rotating the other by 180 °, and are slightly different. Therefore, it is necessary to store them as separate image data. In addition, x _c = (x ₁ + x ₂ ) / 2, y _c = (y ₁ + y ₂ ) / 2 is input as the data of the rotation center position (x _c , y _c ) of the first bonding stage. After inputting the above data, the bonding work is started. Since the rotation center position of the bonding stage changes from time to time during the bonding work, it is necessary to appropriately detect and correct it. For that purpose, first, as shown in FIG. 2B, the θ axis motor of the bonding stage is aligned with the origin in the θ direction, and the camera 19 is moved to the position of the position data (x ₁ , y ₁ ). FIG. 2F shows the monitor screen at this time, and the comparison with the first image data 30 stored by the image processing device 15 is performed to detect the deviation amounts Δx ₁ and Δy ₂ . Then, the position of the point 26 on the IC chip that was used as the mark at this time is (x ₁ +
Δx ₁ , y ₁ + Δy ₁ ) is temporarily held as corrected position data. Next, as shown in FIG. 2 (c), the bonding stage 14 is rotated by 180 ° and the camera 19 is moved to the position of the position data (x ₂ , y ₂ ). FIG. 2 (g) shows the monitor screen at this time. Again, the image processing apparatus compares the stored second image data 31 with each other to detect the amounts Δx ₂ and Δy ₂ and use them as marks. The position of the point 26 on the IC chip is temporarily stored as corrected position data as (x ₂ + Δx ₂ , y ₂ + Δy ₂ ). The corrected position data (x ₁
+ Δx ₁ , y ₁ + Δy ₁ ) and (x ₂ + Δx ₂ , y ₂ + Δy ₂ ), the rotation center position (x _c , y _c ) of the bonding stage 14 is x _c = (x ₁ + Δx ₁
Calculate as + x ₂ + Δx ₂ ) / 2, y _c = (y ₁ + Δy ₁ + y ₂ + Δy ₂ ) / 2, and input it again. As described above, the detection of the rotation center position of the bonding stage can be automated by using the image processing apparatus, and the work which the worker conventionally took about 20 seconds can be performed in about 2 seconds. Further, by performing this detection operation periodically at a certain time interval or at a certain number of IC package operations, it is possible to always grasp the correct rotation center position of the bonding stage and perform good bonding. .

FIG. 3 (a) is a schematic diagram of another embodiment 2 in which the contents of the present invention are used in the TAB ILB bonding apparatus. The Z-axis motor 44 of the heater chip 38 is attached to the bonding head 45.
The camera 37 that shows the alignment of the IC chip 46 and the TAB tape 47 is attached, and the motors 42 and 43 attached to the xy table move the heater chip 38 and the TAB tape 47 in the xy direction during bonding. To do. Also,
The bonding stage 32 can move in the x, y and θ directions to correct the position of the IC chip 46. First, in the input operation before the work, the camera 37 is moved and not shown.
The respective images and positions of the alignment patterns of the TAB tape 47 and the IC chip 46 are stored, and the bonding head and the bonding stage are moved so that the relative positions of the IC chip 46, the TAB tape 47 and the heater chip 38 are aligned. Then, the value of each parameter at this time is input to the bonding control device 34 as offset data. The rotation center position of the bonding stage moves on the bonding stage side because the bonding stage itself moves in the xy direction.
Detects the relative position of the xy axis to the origin on the xy table. For that purpose, the camera 37 is moved to align the center point 50 of the cross line 49 on the monitor with the origin of the xy coordinates on the xy table on the bonding stage side, hold that position, and move only the bonding stage side. , The rotation center position of the bonding stage is detected. First, as shown in FIG. 3B, θ of the bonding stage
Align the axis motor 39 with the origin of the θ axis. A mark 48 is formed on the bonding stage 32, and the bonding stage is moved while looking at the monitor so that the mark 48 coincides with the center point 50 of the cross line 49 on the monitor as shown in FIG. 3 (d). . The position (x ₁ , y ₁ ) of the mark 48 at which the image in the window 51 of the monitor at this time is detected from the first image data 52 or the amount of rotation of the x, y axis motors 40, 41 is stored as position data. deep. Next, as shown in FIG. 3 (c),
The preset angle θ of the bonding stage
Rotate by ₀ . Then, as shown in FIG. 3 (e),
The mark 48 is again aligned with the center point 50 of the cross line 49 on the monitor, and the image in the window 49 and the position (x ₂ , y ₂ ) of the mark 48 at this time are stored as the second image data 53 and position data. Keep it. Then, the rotation center position (x _c , y _c ) of the bonding stage 32 is x _c = (x ₁ + x ₂ ) / 2- (y ₂ -y ₁ ) sinθ ₀ / {2 (1-cosθ ₀ )} y _c = (y ₁ + y ₂ ) / 2 + (x ₂ -x ₁ ) sin θ ₀ / {2 (1-cos θ ₀ )} However, the direction of θ is counterclockwise as shown in FIG. 3 (b), Moreover, 0 ° <θ ₀ <360 ° is calculated and stored as position data, and the input operation of data before work is completed.
With respect to the TAB tape 47 and the IC chip 46 that have been conveyed, the images of the alignment patterns are also captured by moving the camera 38, and the image processing device 33 compares the image data with the image data previously stored, Calculate the shift amount. Then, based on the detected displacement amount, the offset data and the rotation center position data of the bonding stage stored in advance, the bonding control device 34 adjusts the three positions of the heater chip 38, the TAB tape 47 and the IC chip 46. The bonding work is performed by correcting the bonding stage 32 such as the bonding head 45. However, as described above, the position of the center of rotation of the bonding stage changes from time to time, so correction is necessary. Therefore, as before, the camera 35
Is fixed to the origin of the xy coordinates on the xy table on the bonding stage side, and the bonding stage is moved to position data (x ₁ , y
Move it to the position of ₁ ) so that the mark 47 can be seen in the camera 35. Then, as shown in FIG. 3 (f), the deviation amounts Δx ₁ and Δy ₁ are detected by the image processing device 33 by comparison with the previously stored first image data 52, and the position of the mark 48 (x ₁ + Δx ₁ , y ₁ + Δy ₁ ) is held as corrected position data. Next, as shown in FIG. 3C, the bonding stage 32 is rotated by an angle θ ₀ , and the bonding stage 32 is moved to the position of the position data (x ₂ , y ₂ ).
The mark 47 should be visible on the camera 35. Then, as shown in FIG. 3 (g), the image processing device 33 makes a comparison with the second image data stored in advance, detects the deviation amounts Δx ₂ and Δy _2, and detects the position of the mark (x ₂ + Δx ₂ , y ₂ + Δy
₂ ) is stored as corrected position data. Then, the corrected position data (x ₁ + Δx ₁ , y ₁ + Δ held in the memory
y ₁ ) and (x ₂ + Δx ₂ ,, y ₂ + Δy ₂ ) and rotation angle θ ₀ , the rotation center position (x _c , y _c ) of the bonding stage is x _c = (x ₁ + Δx ₁ + x ₂ + Δx ₂ ) / 2- (y ₂ + Δy ₂ -y ₁ -Δy ₁ ) × sin θ ₀ /
{2 × (1-cos θ ₀ )} y _c = (y ₁ + Δy ₁ + y ₂ + Δy ₂ ) / 2 + (x ₂ + Δx ₂ -x ₁ -Δx ₁ ) × sin θ ₀ /
It is calculated as {2 × (1-cos θ ₀ )}. By automatically detecting the rotation center position of the bonding stage in this manner, continuous operation of the apparatus becomes possible, and the efficiency of the bonding work can be improved. Furthermore, this detection method does not necessarily need to rotate the bonding stage by 180 °, and is effective even when the bonding stage cannot be rotated by 180 °.

〔The invention's effect〕

As described above, according to the present invention, by automating the rotation center position of the bonding stage by using the image processing device, it is possible to eliminate the individual difference that occurs when the worker performs the detection, and it is possible to shorten the detection time. is there. Moreover, by operating the device itself to automatically correct the rotation center position of the bonding stage at preset time intervals or for each number of IC package operations,
The number of man-hours required for the operator can be reduced and the occurrence of defective bonding position misalignment can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the present invention, FIG. 2 (a) is a schematic diagram of an embodiment of the present invention, and FIGS. 2 (b) and 2 (c) are plan views of a bonding stage section. Figure, Figure 2 (d), (e), (f),
3G is a schematic view of a monitor screen, FIG. 3A is a schematic view of another embodiment of the present invention, FIGS. 3B and 3C are plan views of the bonding stage section, and FIG. d), (e),
(F) and (g) are schematic views of the monitor screen, FIG. 4 is a schematic view of the prior art, FIGS. 5 (a) and (b) are plan views of the bonding stage portion, and FIGS. 5 (c) and (c). d), (e),
(F) is a schematic diagram of a monitor screen. 1 ... Bonding stage, 2 ... Image processing device, 3
... Bonding control device, 4 ... Deviation amount detection device, 5
...... Calculator, 6 …… Camera, 7 …… θ axis drive system, 8 ・ ・ ・
… XY stage, 9 …… Bonding target, 10 …… First
Image data storage device, 11 ... Second image data storage device,
12 ... Mark position data storage device, 13 ... Rotation center position data storage device, 14 ... Bonding stage, 15 ... Image processing device, 16 ... Bonding control device, 17 ... x, y
Stage controller, 18 ... θ-axis motor controller, 19 ……
Camera, 20 …… θ-axis motor, 21 …… x-axis motor, 22 ……
y-axis motor, 23 ... Bonding head, 24 ... IC case, 25 ... IC chip, 26 ... Characteristic point on IC chip (bonding pad corner), 27 ... Cross line on monitor, 28 ... … Wind, 29 …… Crossline center point, 30 …… First image data, 31 …… Second image data, 32
...... Bonding stage, 33 …… Image processing device, 34…
... Bonding controller, 35 ... Bonding head controller, 36 ... Bonding stage controller, 37 ...
Camera, 38 ... Heater chip, 39 ... θ-axis motor, 40 ...
... x-axis motor, 41 ... y-axis motor, 42 ... x-axis motor,
43 …… y axis motor, 44 …… z axis motor, 45 …… bonding head, 46 …… IC chip, 47 …… TAB tape, 48…
… Marks, 49… Cross line on monitor, 50… Center point of cross line, 51… Window, 52… First image data, 53… Second image data, 54… Bonding stage, 55… … Bonding controller, 56… Camera, 57…
… Θ-axis motor, 58 …… xy table, 59 …… input device, 60
...... Monitor, 61 …… IC case, 62 …… IC chip, 63 ……
Characteristic point on the IC chip (corner of bonding pad),
64 …… Cross line, 65 …… Cross line center point.

Claims (1)

[Claims] 1. A bonding stage, such as a wedge bonder or an inner lead bonding (ILB) or an outer lead bonding (OLB) for rotating a bonding object, comprising a bonding stage,
A control device for controlling the rotating operation of the bonding stage, and a mark position data storage device for storing position data for moving the bonding stage to a preset reference position when detecting the rotational center position of the bonding stage. A first image data storage device for storing first image data of a preset area centered on the reference position, and second image data centered on the reference position by rotating the bonding stage by a predetermined angle. A storage device, a displacement amount detection device for detecting the displacement amount by comparing the first image data and the second image data with the position data from the mark position data storage device, and the bonding according to the displacement amount. An arithmetic unit for calculating the corrected rotation center position of the stage and the corrected bonding stay. Rotation center position data storage device for storing the rotation center position of the bonding stage, and the rotation operation of the bonding stage based on the corrected rotation shaft center position of the bonding stage stored in the rotation center position data storage device. A bonding apparatus, wherein the bonding apparatus is controlled by the control device.