JPH04259807A - Image input device for linear object inspection - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device used for three-dimensionally inspecting the appearance of linear objects such as bonding wires.

0002

2. Description of the Related Art A bonding wire to be inspected usually has a shape as shown in FIG. 14 and the lead 10b of the lead frame 10 are connected by a bonding wire 16.

However, due to an abnormality in the clamper of the wire bonder, as shown in FIG.
6 becomes loose and becomes too high, as shown in the same figure (C),
The center portion of the bonding wire 16 may sag, or the bonding wire 16 may become too tensioned as shown in FIG.

The bonding wire 16 has a diameter of 25 to 3
Since it is extremely thin at 0 μm, when resin molding is performed after wire bonding, the bonding wire 1
The force applied to the bonding wire 16 may cause an abnormality in the bonding wire 16. For example, a bonding wire 16 that is too loose may short-circuit with an adjacent bonding wire 16,
A hanging bonding wire 16 may short-circuit with a grounded frame or a guard ring formed at the edge of a chip, or a bonding wire 16 that is too stretched may break.

[0005] Such shape defects may occur repeatedly due to the same cause. Therefore, it is necessary to inspect the shape of the bonding wire 16 after bonding and before molding.

[0006] Conventionally, therefore, visual inspection was carried out using an optical microscope. However, with the increase in the scale of semiconductor integrated circuits, the number of bonding wires 16 for one semiconductor chip 12 is, for example, 400 to 50 at intervals of about 100 μm.
Some have 0 wires bonded. For this reason, 1
Each time, a large number of bonding wires 16 must be inspected in a short period of time, and this must be repeated, resulting in significant fatigue and the risk of overlooking defects. From this situation,
Attempts have been made to automate the visual inspection of the bonding wire 16.

FIG. 6 shows an image input device for linear object inspection to which stereoscopic binocular viewing is applied. This method involves arranging a pair of cameras 181 and 182 facing each other on the inspection target, and
and 182 output images, camera 181 and camera 182
The three-dimensional shape of the bonding wire 16 is measured from the parallax.

FIG. 7 shows an optical system of an image input device for inspecting linear objects to which the slit light projection method is applied. In this method, a slit light projector 20 irradiates the bonding wire 16 with slit light in the direction of cutting the bonding wire 16, and a light spot on the bonding wire 16 is detected by a camera 18.
and bonding wire 16 by triangulation method.
It measures the three-dimensional shape of.

[0009]

[Problems to be Solved by the Invention] However, in order to inspect all the bonding wires 16 of one sample,
There is a problem in that the apparatus becomes complicated because it requires a large number of sets of cameras 181 and 182 shown in FIG. 6, or the inspection objects must be placed one by one on an XYθ stage and moved. . The same applies to the linear object inspection image input device shown in FIG.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide an image for inspecting linear objects with a simple configuration capable of obtaining the image data necessary to detect the three-dimensional shapes of all linear objects in one sample. The purpose is to provide an input device.

[0011]

[Means for Solving the Problems and Their Effects] In order to achieve this object, an image input device for linear object inspection according to the first invention includes a rotating member, a motor for rotating the rotating member, and a motor for rotating the rotating member. It includes a pair of cameras that are attached to a rotating member and that take images of a linear object from different directions and output image data.

When the motor is turned on, the rotating member rotates, and the camera takes an image every time the rotating member rotates, for example, 30 degrees. If two pairs of cameras are provided, for example, and the rotating member is rotated by 180 degrees, sufficient image data can be obtained to measure the three-dimensional shapes of all linear objects in one sample using stereoscopic binocular viewing. Therefore, in this case, it is sufficient to rotate the rotating member 180 degrees for each sample, and the operation of the image input device for linear object inspection is simple and high-speed operation is possible.

Furthermore, the configuration of the image input device for inspecting linear objects is simple, and an inexpensive image input device for inspecting linear objects can be provided.

The image input device for inspecting a linear object according to the second invention includes a rotating member, a motor for rotating the rotating member, and a motor attached to the rotating member that moves the linear object in a direction to cut the linear object. It includes a light projector that projects slit light onto an object, and a camera that is attached to the rotating member and that images the projected linear object and outputs image data.

The operation of this image input device for linear object inspection is also similar to that of the first image input device for linear object inspection. However, when this image input device for linear object inspection is used, triangulation is applied to the output image of the camera to measure the three-dimensional shape of the linear object.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

(1) First Embodiment FIG. 1 shows a first embodiment of an image input device for inspecting linear objects. This image input device for linear object inspection applies stereoscopic binocular viewing, and includes two sets of image input devices with the same configuration.

A pair of binocular tubes 24 and 34 are fixed on the rotating disk 22. A pair of cameras 261 and 262 are arranged at the top of the binocular tube 24 with their optical axes perpendicular to the rotating disk 22. Also,
An aperture plate 28 is arranged at the bottom of the binocular barrel 24, and circular holes 28a and 28b are formed in the aperture plate 28 to correspond to the cameras 261 and 262. Below the aperture plate 28, an objective lens 30 for magnifying vision common to the cameras 261 and 262, shown in FIG. 2, is arranged. In addition, the objective lens for the camera 261 and the camera 26
If an objective lens for 2 is provided separately, the aperture plate 28
is no longer necessary, but the distance between cameras 261 and 262 needs to be increased, which increases the size of the device.
It is preferable to configure it as in this embodiment.

The binocular tube 34 side has the same configuration as the binocular tube 24 side, and in the figure, 361 and 362 are cameras, 38 is an aperture plate, and 38a is a circular hole.

A rotating shaft 4 is located at the center of the rotating disk 22.
The lower end of 2 is fixed perpendicularly to the rotating disk 22. The upper end of the rotating shaft 42 is passed through the supporting shaft piece 44a of the arm 44, the pulley 45, and the supporting shaft piece 44b of the arm 44, and the pulley 45 is fixed to the rotating shaft 42, so that the rotating shaft 42 can freely rotate around the arm 44. is supported by This pulley 45 and
A belt 48 is wound around a pulley 46a fixed to the output shaft of the pulse motor 46. The arm 44 and the pulse motor 46 are fixed to a fixed member (not shown).

The image input device for inspecting linear objects having such a simple configuration is placed above a conveyance device that intermittently feeds samples mounted at regular intervals, and is placed below the rotating disk 22 to perform visual inspection of bonding wires. The sample is paused for

In the above configuration, when the pulse motor 46 is turned on, the rotating disk 22 rotates and the camera 261
, 262, 361, and 362 are performed, for example, every time the rotating disk 22 rotates by 30 degrees. By rotating the rotating disk 22 by 180 degrees, image data sufficient to measure the three-dimensional shape of all the bonding wires 16 can be obtained. Therefore, it is sufficient to rotate the rotary disk 22 by 180 degrees for each sample, and the operation of the image input device for linear object inspection is simple.

FIG. 2 shows a linear object inspection device to which the image input device having the above configuration is applied.

The rotation of the pulse motor 46 is controlled by a motor controller 50 via a driver 52. The image data output from the cameras 261 and 262 is supplied to image input circuits 541 and 542 and converted into digital values based on the rotation angle signal from the motor controller 50 and the synchronization signal from the cameras 261 and 262. Write addresses are generated and written to the image storage units 56a and 56b of the microcomputer 56, respectively.

The hardware of the microcomputer 56 is of a well-known configuration, and its software configuration is shown in FIG. 2 as functional blocks 56a to 56f.

The window storage section 56c stores in advance the shape and position of the window for each bonding wire 16 based on the design data to be inspected. The wire shape measuring section 56d refers to this window and calculates each bonding wire 16 from the image storage sections 56a and 56b.
The image is cut out, and the shape of each bonding wire 16 is measured based on stereoscopic binocular viewing. On the other hand, the tolerance range of the shape of the bonding wire 16 is stored in the tolerance storage section 56e. The quality determining unit 56f determines whether the shape of the bonding wire 16 measured by the wire shape measuring unit 56d is within this allowable range, and if it is determined that there is a defect, sends an alarm signal and Data identifying the wire 16 is output. This data is displayed on a display (not shown) and recorded on a recorder, for example.

The same processing as described above is also performed on the output images of cameras 361 and 362 shown in FIG.

In this way, one semiconductor chip 12
All bonding wires 16 are automatically tested and this is repeated.

(2) Second Embodiment FIG. 3 shows an image input device for linear object inspection according to a second embodiment. This image input device for linear object inspection applies the slit light projection method, and includes two sets of image input devices with the same configuration.

A rotary disk 62 is rotatably supported in a circular hole on the fixed base plate 60. Further, a pulse motor 46 is fixed on the base plate 60. Rotating disk 62 and pulse motor 4
A belt 64 is attached to the pulley attached to the output shaft of 6.
is wrapped around it. A pair of peep holes 62a and 62b are formed in the rotating disk 62 for viewing a sample placed below the base plate 60. peephole 6
2a, a pair of cameras 181 and a slit light projector 201 are fixed to the rotating disk 62, and the peephole 62
Corresponding to b, a pair of cameras 182 and a slit light projector 202 are fixed to the rotating disk 62. The optical axes of the camera 181 and the camera 182 are perpendicular to the base plate 60, and the optical axes of the slit light projectors 201 and 202 are inclined with respect to these optical axes.

The image input device for inspecting linear objects having such a simple configuration is placed above a conveyance device that intermittently feeds samples mounted at regular intervals, and is placed below the rotating disk 62 to inspect the appearance of bonding wires. The sample is paused for

In the above configuration, when the pulse motor 46 is turned on, the rotating disk 62 rotates, and the camera 181
and 182, for example, when the rotating disk 62 is
This is done every 0° rotation. Rotating disk 62 180
If rotated by .degree., sufficient image data can be obtained to measure the three-dimensional shape of all bonding wires 16. Therefore, it is sufficient to rotate the rotary disk 62 by 180 degrees for each sample, and the operation of the optical system of the image input device for linear object inspection is simple.

FIG. 4 shows a linear object inspection device to which the image input device having the above configuration is applied.

The slit light projector 201 includes a laser 20a
, a condensing lens 20b, a cylindrical concave lens 20c, and a diffraction grating 20d. The light beam emitted from the laser 20a is focused onto the cylindrical concave lens 20c by the condenser lens 20b, and
The 0th order, 1st order and -1st order diffracted light from the diffraction grating 20d
It passes through and becomes a slit light. These slit lights cause light spots P1, P2, and P3 on the bonding wire 16.
is formed. Light spots P1, P2 and P3 are camera 181
The image is taken with

Similar to the first embodiment, the rotation of the pulse motor 46 is controlled by a motor controller 50 via a driver 52. The image data output from the camera 181 is supplied to the image input circuit 54, where it is converted into a digital value, and a write address is generated based on the rotation angle signal from the motor controller 50 and the synchronization signal from the camera 181. , is written into the image storage section 66a of the microcomputer 66.

The hardware of the microcomputer 66 is of a well-known configuration, and its software configuration is shown in FIG. 4 by functional blocks 66a to 66f.

The window storage section 66c stores in advance the shape and position of the window for each bonding wire 16 based on the design data to be inspected. The wire shape measurement section 66d refers to this window, cuts out an image of each bonding wire 16 from the image storage section 66a, and measures the shape of each bonding wire 16 based on triangulation. On the other hand, the tolerance range of the shape of the bonding wire 16 is stored in the tolerance storage section 66e. The quality determining section 66f includes a wire shape measuring section 66.
It is checked whether the shape of the bonding wire 16 measured in step d is within this allowable range to determine pass/fail, and if it is determined that there is a defect, an alarm signal and data identifying the bonding wire 16 are output. . This data is displayed on a display (not shown) and recorded on a recorder, for example.

The same processing as described above is also performed on the output image of the camera 182 shown in FIG.

In this way, one semiconductor chip 12
All bonding wires 16 are automatically tested and this is repeated.

[0040]

Effects of the Invention The image input device for linear object inspection according to the first invention includes a rotating member, a motor that rotates the rotating member, and a motor that is attached to the rotating member and that images the linear object from different directions. The image input device for inspecting linear objects according to the second aspect of the present invention includes a rotating member, a motor for rotating the rotating member, and a pair of cameras that output image data using the rotating member. a light projector that is attached to the rotary member and projects a slit light onto the linear object in a direction to cut the linear object; a camera that is attached to the rotating member that images the projected linear object and outputs image data; This configuration has the effect of being able to obtain the image data necessary to detect the three-dimensional shape of all linear objects in one sample with a simple configuration, contributing to the cost reduction of linear object inspection equipment. There's a lot to do.

Moreover, the operation is a simple rotational operation, which has the effect of enabling high-speed processing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an image input device for inspecting linear objects according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a linear object inspection device to which the image input device of FIG. 1 is applied.

FIG. 3 is a perspective view showing an image input device for linear object inspection according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a linear object inspection device to which the image input device of FIG. 3 is applied.

FIG. 5 is a diagram showing various shapes of bonding wires.

FIG. 6 is a perspective view showing a conventional image input device for inspecting linear objects.

FIG. 7 is a perspective view showing a conventional image input device for inspecting linear objects.

[Explanation of symbols]

10 Lead frame 10a Island 10b Lead 12 Semiconductor chip 14 Pad 16 Bonding wire 18, 181, 182, 261, 262, 361, 36
2 Cameras 20, 201, 202 Slit light projector 20a
Laser 20b Condenser lens 20c Cylindrical concave lens 20d Diffraction gratings 22, 62 Rotating disks 24, 34 Binocular tubes 28, 38 Aperture plates 28a, 28b, 38a Hole 30 Objective lens 42 Rotating shaft 44 Arms 45, 46a Pulley 46 Pulse Motors 48, 64 Belt 60 Base plates 62a, 62b Peephole

Claims (2)

[Claims] 1. A rotating member (22), a motor (46) for rotating the rotating member, and a motor (46) attached to the rotating member,
A pair of cameras (261, 262, 361) that image the linear object (16) from different directions and output image data.
, 362). 2. A rotating member (62), a motor (46) for rotating the rotating member, and a motor (46) attached to the rotating member,
A projector (201, 202) that projects a slit light onto the linear object in the direction of cutting the linear object (16), and a light projector (201, 202) that is attached to the rotating member and images the projected linear object to create an image. An image input device for inspecting a linear object, comprising: a camera (181, 182) that outputs data.