JPH01246841A - Wire bonding device - Google Patents

Abstract

PURPOSE:To make possible the high-speed and high-accuracy inspection of a bonding wire by using a simple mechanism by a method wherein illuminators are moved up and down to image the bonding wire in every step of the illuminators and the form of the three-dimensional loop of the wire is found on the basis of image data and the moved positions of the illuminators. CONSTITUTION:First and second illuminators 14 and 15 are moved up and down to irradiate parallel rays 14' and 15' on a bonding wire 12 and an image sensing device 23 images the wire 12 in every movement of the illuminators. An image signal is stored in an image memory 26 and an image processing circuit 25 makes out image data on the form of the three-dimensional loop of the wire 12 on the basis of image data in the memory 26 and the moved positions of the illuminators 14 and 15. Moreover, an inspecting controller 27 inspects the form of the three-dimensional loop of the wire 12 to decide the good or bad of the form. An illumination moving controller 22 has an imaging area moving mechanism 28 and makes the illuminators 14 and 15 and the device 23 move integrally. Thereby, the wire can be inspected by a simple mechanism at high speed and with a high accuracy.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a wire bonding device.

(Prior art) ASICs such as microprocessors and gate arrays
(Application Apecirlc I
C, application-specific integrated circuits) have a large number of electrodes. Therefore, in order to output an electrical signal through each electrode (hereinafter referred to as a bonding pad) of this ASIC, each bonding pad and each electrode of the lead frame must be connected by wire bonding.

Note that the connected wire is referred to as a bonding wire. The number of bonding wires wire-bonded in this way is about 180 pieces, and the wire connection interval is about 200 μm.

By the way, in such wire bonding, an inspection is performed to see if each bonding wire is correctly connected. This inspection is performed visually by an operator, but it is difficult to quantitatively determine the shape of the bonding wire with such visual inspection, and even moreover, it may be overlooked. Therefore, there is a technology that automates such inspection. This inspection is a two-dimensional method. First, as shown in FIG. 14, the ASICI and lead frame 2 before wire bonding are imaged to obtain image data, and then as shown in FIG. AS after wire bonding to
The ICI and lead frame 2 are imaged to obtain image data. Note that 3 is a bonding wire. Then, by determining the difference between these image data, image data of only the bonding wire 3 as shown in FIG. 1B is obtained. However, from this image data, it is inspected whether each bonding wire 3 is accurately connected between the ASICI and the lead frame 2.

However, in such an inspection method, all bonding wires 3 connected to one ASICI are inspected at once, so it is difficult to inspect each bonding wire 3 one by one. In particular, when there are a large number of bonding wires 3 such as in ASICI, it is impossible to inspect the shape of each bonding wire 3 one by one.

(Problems to be Solved by the Invention) As described above, it has been difficult to accurately inspect the shape of each bonding wire.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wire bonding apparatus having a function of inspecting the three-dimensional loop shape of a bonding wire easily and at high speed.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a wire bonding device including a bonding wire inspection section that inspects the three-dimensional loop shape of a plurality of bonding wires wire-bonded between two objects to be processed. In the apparatus, the bonding wire inspection section includes: a pair of light irradiation means for irradiating colored light; a vertical moving means for moving the light irradiation means in the vertical direction with respect to the bonding wire; an imaging device arranged above the bonding wire and capturing an image of the bonding wire while the light irradiation means is moved upward or downward by the moving means; An image processing means that calculates the three-dimensional loop shape of the bonding wire from each image data obtained by imaging with the imaging device and the movement position of the light irradiation means, and the light irradiation means and the imaging device are integrated for all the bonding wires. This wire bonding apparatus is provided with an imaging area moving means for moving the imaging area.

Further, the present invention provides a wire bonding apparatus including a bonding wire inspection section that inspects the three-dimensional loop shape of a plurality of bonding wires wire-bonded between two objects to be processed, wherein the bonding wire inspection section includes:
one stage of first light irradiation means arranged along the entire circumference along the connection position of each bonding wire and irradiating parallel light to all the bonding wires from the bonding direction of the bonding wire; a second light irradiation means disposed at a central position and irradiating all the bonding wires with parallel light from a direction opposite to the first light irradiation means, and moving these first and second light irradiation means in the vertical direction with respect to the bonding wire. a plurality of imaging devices arranged above the bonding wire for each light irradiation means and capturing images of the bonding wire while the light irradiation means is moved upward or downward by the movement means, and these imaging devices Wire bonding that attempts to achieve the above object by comprising an image processing means for determining a three-dimensional loop shape of all bonding wires from each image data of each imaging area obtained by imaging and the movement position of each light irradiation means. It is a device.

(Function) By providing such means, a predetermined number of bonding wires are irradiated with parallel light by the light irradiation means, and at the same time, the light irradiation means is moved vertically relative to the bonding wires by the vertical movement means. will be moved.

At this time, the bonding wire is imaged by the imaging device, and the image processing means determines the three-dimensional loop shape of the bonding wire from the image data and the moving position of the light irradiation means. Then, the light irradiation means and the imaging device are moved integrally with respect to all the bonding wires.

Moreover, by providing the above means, all the bonding wires are irradiated with parallel light by the first and second light irradiation means respectively arranged along the connection position of each bonding wire and at the center position, and together with this, These first
The second light irradiation means is moved in the vertical direction relative to the bonding wire by the vertical movement means. At this time, all the bonding wires are imaged for each imaging area by each imaging device, and the image processing means determines the three-dimensional loop shape of the bonding wire from each image data for each imaging area and the moving position of the light irradiation means.

(Example) Hereinafter, a first example of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a wire bonding apparatus. In the same figure, 10 is an ASIC as the object to be processed, and 11
is a lead frame.

These ASICIOs and the lead frame 11 are connected by a plurality of bonding wires 12.

Now, 13 is a light irradiation means, which irradiates a predetermined number of bonding wires 12 out of each bonding wire 12 with k*1 parallel light from each opposing direction in the bonding direction of the bonding wires 12. It is something. The specific configuration is as follows. A
A first illuminator 14 is disposed directly above the center position of SrClo, and a second illuminator 15 is disposed at a position opposite to the first illuminator 14 in the bonding direction of the bonding wire 2, as shown in FIG. is located. These first
and second illuminators 14 and 15 respectively in opposite directions.
A plane light 14-. It is designed to emit 15-.

However, each of the light emitting ports of the first and second illuminators 14.15 is provided with an optical lens 16.17 for forming plane light, respectively. On the other hand, 18 is a laser oscillation device, and the laser beam output from this laser oscillation device 18 is sent to 6 first and second illuminators 14 and 15 through a condenser lens 19 and an optical fiber (not shown). It has become. Note that the laser oscillation device 18 is controlled by a lighting controller 20 to control on/off of laser output and output power.

Further, the first and second illuminators 14 and 15 are provided with a lighting movement mechanism 21 and a lighting movement controller 22 as upward movement means.
The illumination moving device M21 and the illumination movement controller 22 are capable of moving in the direction of arrow (a), that is, in the upward direction with respect to the bonding wire 12. Note that the illuminators 14 and 15 move in steps.

Reference numeral 23 denotes an imaging device, which is arranged above the bonding wire 12 and captures an image of the bonding wire 12 each time the first and second illuminators 14 and 15 move stepwise. ing. The image signal output from the imaging device 23 is converted into a digital image signal by an A/D (analog/digital) converter 24, and is stored as image data in an image memory 26 through an image processing circuit 25. It looks like this. This image processing circuit 25 has a function of creating shape image data of the three-dimensional loop of the bonding wire 12 from each image data stored in the image memory 26 and the movement positions of the first and second illuminators 14 and 15. It is something.

Then, the inspection controller 27 is the lighting controller 20
．． It has a function of issuing commands to the illumination movement controller 22 and the image processing circuit 25 to execute a bonding wire inspection, and also determining whether the shape of the bonding wire 12 is good or bad from the shape image data created by the image processing circuit 25. It is something.

The illumination movement controller 22 is also provided with an imaging area movement mechanism 28 . This imaging area moving mechanism 28 moves the first and second illuminators 14.15 and the imaging device 23 into a third
As shown in the figure, integrally a→b -c..., a-→b
'→C+...

Thus, each image area obtained by the imaging device 23 is A, B, C, . . . as shown in FIG.

Next, the operation of the apparatus configured as described above will be explained according to the inspection flowcharts shown in FIGS. 5 and 6.

First, as an initial process, laser light is output from the laser oscillation device 18 and sent to the first and second illuminators 14 and 15.
The positions of the laser beams 14=, 15- emitted from the first and second illuminators 14, 15, respectively, are set to 11. Further, the second illuminator 15 and the imaging device 23 are arranged at predetermined positions as shown in FIG. 3, and the imaging device 23 is set so that the imaging area A is imaged.

In this state, the inspection controller 27
sends a movement command to the illumination movement controller 22 and also sends a processing execution command to the image processing circuit 25. Here, each of the first and second illuminators 14 .
Let n be the number of steps for lowering 15. However, in step el of the image capture flowchart shown in FIG. 6, the inspection controller 27 first selects ri-IJ, that is, measurement position 1! is set, and a capture command is sent to the image processing circuit 25 in step c3. Note that step e
2, a command to move to the measurement position 11 is sent, but since the first and second illuminators 14, 15 have already been set to the measurement position 11 in the initial processing, no movement command is sent here. When each measurement position of the first and second illuminators 14.15 is thus positioned at it,
The image processing circuit 25 takes in the digital image signal digitally converted by the A/D converter 24 and stores it in the image memory 26.
is stored as image data. The image data at this time is the image data (ll) shown in FIG. 7, in which the five bonding wires 12 are irradiated with plane light, and the shading level of the irradiated portion is high. Next, in step c5, it is determined whether all of the measurement positions in have been imaged. In this case, since only the measurement position 11 has been imaged, in step e6, ri-2J is determined and the process moves to step o2. In step c2, the inspection controller 27 sends a movement command to the illumination movement controller 22 to move it to the measurement position 12. As a result, the first and second illuminators 14.
15 are lowered and their irradiation light is set at the measurement position 12. Then, in step e3, the image processing circuit 25 takes in the digital image signal at this time and stores it in the image memory 26 as image data (12).

Hereinafter, this process is repeated until each measurement position of the first and second illuminators 14.15 reaches In, and at that time each image data (11) to (In) as shown in FIG. It is stored in memory 26.

When the acquisition of digital image signals at each measurement position N-1n is completed in this way, the process moves to step S2, and the image processing circuit 25 lowers the first and second illuminators 14 and 15 from the inspection controller 27 in a stepwise manner. In response to each movement position at the time, these movement positions and each image data (if) ~
(in). Then, the image processing circuit 25 adds each image data (il) to (in) to create image data as shown in FIG. 8, and then performs bonding as shown in FIG. 9 based on each movement position. Image data of a three-dimensional loop shape of the bonding wire 12 when the wire 12 is viewed from the side is created. Then, from this image data, the shape of the bonding wire 12, such as the underloop and average height, is determined.

Therefore, in step S3, the inspection controller 27
determines whether the obtained underloop, average height, etc. are predetermined values, and if they are different from the predetermined values, step s4
Move to. However, if the underlube, the dead center height, etc. deviate from predetermined values, the inspection controller 27 displays an error on the display device (not shown) in step S5 to notify that the bonding wire 12 is defective.

If it is not determined to be defective in the determination in step S8, it is determined in step s4 whether the inspection of all imaging areas A to H has been completed, and in this case, since only imaging area A has been completed, the process proceeds to step s6. Then, in step s6, the inspection controller 27 sends a movement command to the illumination movement controller 22 to move the second illuminator 15 to the a position and to move the imaging device 23 to the a' position. Steps 81 to s3 are then executed again to test each bonding wire 12 in the imaging area B, and finally all the bonding wires up to the imaging area H are tested.

In this way, in the first embodiment, the bonding wire 12 has >lJ- row light 14-. At the same time, the first and second illuminators 14 and 15 are moved in the vertical direction with respect to the bonding wire 12, and each image and image data obtained by imaging at this time and the first and second illuminators 14 are ．．
The three-dimensional loop shape of the bonding wire 12 is determined from the movement position of the first and second illuminators 14 and 15.
The entire bonding wire 12 is integrated with the image pickup device 23.
Since the configuration is such that each bonding wire 12 is moved at high speed even if there are many bonding wires 12, each bonding wire 12 can be moved at high speed.
2 can be obtained automatically and with high precision. Furthermore, since the image processing is a method of adding up each image data for each measurement position and then taking the measurement positions into consideration to obtain the shape of the bonding wire 12, simple image processing is sufficient and the processing speed can be increased.

Next, a second embodiment of the present invention will be described.

FIG. 10 is a block diagram of the bonding wire inspection apparatus seen from the side, and FIG. 11 is a block diagram of the bonding wire inspection apparatus seen from above.

This apparatus inspects each bonding wire 12 in each imaging area A to H shown in FIG. 4 at once. That is, the first illuminator 30 is placed directly above the center position of the ASICIO, and the second illuminators 31a to 31h are placed around the first illuminator 30.

These first illuminators 30 and each second illuminator 31a
-31h can be moved in the direction of arrow (b) by a moving mechanism (not shown). Further, each imaging device 32a to 32h is arranged so as to take an image of each imaging area A-H shown in FIG. 4. Each image signal outputted from these imaging devices 32a to 32h is converted into a digital image signal and stored as image data in separate areas of each imaging area A to H in the image memory. In addition,
The laser oscillation device that sends laser light to the first and second illuminators 30.31a to 31h, the image processing circuit, the inspection controller, etc. are the same as those in the first embodiment, and will therefore be omitted.

Next, the operation of the apparatus configured as described above will be explained according to the inspection flowchart shown in FIG. Note that the number of steps for dropping the first and second illuminators 14.15 is n, and each node 1 and second illuminator 30.3 are set as the initial state.
The radiation positions of 1a to 31h are set to 11. However, in step r1, each of the imaging devices 32a to 32
Each image signal output from h is captured. The image capture in step r1 is performed in the same manner as the image capture flowchart shown in FIG. That is,
When each irradiation position of the first and second illuminators 30.31a to 31h is positioned at 11, each of the imaging devices 32a to '3
Each image signal outputted from 2h is converted into a digital image signal and stored as image data in separate areas of each imaging area A to H of the image memory. And the first
and each measurement position of the second illuminators 30.31a to 31h is i.
The image data is lowered until it reaches n, and each image data at that time is stored in separate areas for each imaging area A to H of the image memory.

When the acquisition of digital image signals at each measurement position If-in is completed in this way, the process moves to step "2" and the first
Then, each movement position of the second illuminators 30.31a to 31h is made to correspond to each image data 11 to 11 for each imaging area A-H, and then based on each movement position, data as shown in FIG. Image data of the three-dimensional loop shape of the bonding wire 12 when viewed from the side is created for each imaging area A-H. Then, the three-dimensional loop shape of the bonding wire 12, such as the underloop and average height, is determined from these image data, and the next step r3
It is determined whether the underloop, average height, etc. obtained in step 4 are within predetermined values, and if the underloop, average height, etc. deviate from the predetermined values, a display device (not shown) is displayed in step 4. An error message is displayed to notify that the bonding wire 12 is defective.

In this way, in the second embodiment, all the bonding wires 12 are irradiated with parallel light, and the first and second illuminators 30.31a to 31h are moved in the vertical direction,
Since the configuration is such that the three-dimensional shape of all the bonding wires 12 is obtained from each image data for each imaging area A-H obtained at this time and the movement positions of the first and second illuminators 30.31a to 31h, the above-mentioned As in the first embodiment, even if the number of bonding wires 12 is large, the shape of each bonding wire 12 can be obtained automatically and with high precision at high speed. Since the method adds the image data and then takes into account the fixed position of 7111J to obtain the shape of the bonding wire 12, simple image processing is required and the processing speed can be increased. Moreover, all the bonding wires 12 for one ASICIO can be inspected, and the inspection speed can be further increased.

Note that the present invention is not limited to the above embodiments, and may be modified without departing from the spirit thereof. For example, as shown in FIG. 13, the light irradiation means converts the laser light output from the laser oscillation device 40 into planar light using an optical lens 40a and sends it to the half mirror 41.
The signal is branched into two paths at 41 and sent to total reflection mirrors 42 and 43. Of these, the laser beam reflected by the total reflection mirror 43 is irradiated onto the bonding wire 12, and the laser beam reflected by the other total reflection mirror 42 is further reflected by the total reflection mirror 44 and irradiated onto the bonding wire 12. You can do it like this. And each total reflection mirror 43.44
It is only necessary to configure it so that it can be moved in the direction of arrow (C) by a moving mechanism 45.

Further, although the first and second illuminators are lowered from above, they may be raised from above, or they may be moved continuously. In this case, a shutter may be attached to the imaging device and the shutter may be turned off each time the first and second illuminators reach a predetermined position.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a wire bonding apparatus that can inspect the three-dimensional loop shape of a bonding wire in a cylinder at high speed.

[Brief explanation of the drawing]

1 to 9 are diagrams for explaining a first embodiment of the wire bonding apparatus according to the present invention, in which FIG. 1 is a configuration diagram, FIG. 2 is a layout diagram of an illuminator, and FIG. 4 is a diagram showing the movement of the illuminator and imaging device, FIG. 4 is a diagram showing each imaging area, FIGS. 5 and 6 are inspection flowcharts, and FIGS. 7 to 9
The figures are diagrams for explaining image processing, Figures 10 to 12.
The figure is a diagram for explaining a second embodiment of the present invention,
10 and 11 are configuration diagrams, FIG. 12 is an inspection flowchart, FIG. 13 is a configuration diagram of a modified example, and FIGS. 14 to 16 are diagrams for explaining the prior art. 10...ASIC (Application Specific Integrated Circuit), 11...
Lead frame, 12... Bonding wire, 13
...Light irradiation means, 14...First illuminator, 15...
Second illuminator, 18... Laser oscillation device, 20... Lighting controller, 21... Vertical movement mechanism, 22...
Lighting movement controller, 23...imaging device, 25...
- Image processing circuit, 26... image memory, 27... inspection controller, 28... imaging area movement mechanism. Applicant's Representative Patent Attorney Takehiko Suzue Figure 7 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16

Claims (2)

[Claims] (1) In a wire bonding apparatus including a bonding wire inspection unit that inspects the three-dimensional loop shape of a plurality of bonding wires wire-bonded between two objects to be processed, the bonding wire inspection unit a pair of light irradiation means for irradiating parallel light onto a predetermined number of bonding wires among the bonding wires from opposite directions, and moving the light irradiation means in a vertical direction with respect to the bonding wires; vertical movement means,
an imaging device that is arranged above the bonding wire and images the bonding wire while the light irradiation means is moved upward or downward by the moving device; and each image data obtained by imaging with this imaging device and the light irradiation. An image processing means for determining a three-dimensional loop shape of the bonding wire from the movement position of the means, and an imaging area moving means for integrally moving the light irradiation means and the imaging device with respect to all the bonding wires. A wire bonding device characterized by: (2) In a wire bonding apparatus including a bonding wire inspection section that inspects the three-dimensional loop shape of a plurality of bonding wires wire-bonded between two objects to be processed, the bonding wire inspection section includes a first light irradiation means arranged along the entire circumference along the wire connection position and irradiating parallel light to all the bonding wires from the bonding direction of the bonding wire; and a first light irradiation means arranged at the center position of these first light irradiation means. and a second light irradiation means for irradiating parallel light onto all of the bonding wires from a direction opposite to the first light irradiation means, and moving these first and second light irradiation means in a vertical direction with respect to the bonding wires. a plurality of imaging devices disposed above the bonding wire for each of the light irradiation means and for capturing an image of the bonding wire while the light irradiation means is moved upward or downward by the movement means; The present invention is characterized by comprising an image processing means for determining a three-dimensional loop shape of all the bonding wires from each image data of each imaging area obtained by imaging with an imaging device and the movement position of each of the light irradiation means. Wire bonding equipment.