JPH10141925A - Appearance inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurately inspect a semiconductor device for appearance in a short time under a space- and cost-saving condition. SOLUTION: A mirror optical system 13 is arranged above, namely, around a semiconductor device 11. An image pickup device 12 simultaneously picks up the image of the upper surface of the device 11 and the images of the four side faces of the device 11 which are picked up through the optical system 13. An image processing device 14 inspects the device 11 for appearance by comparing video signals supplied from the image pickup device 12 with basic patterns stored in a second memory 19. Since the necessity of pluralities of cameras and image processing devices is eliminated at the time of picking up the images of the side faces for the inspection, the semiconductor device 11 can be inspected for appearance in a short time under a space- and cost- saving condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an appearance inspection apparatus used for inspecting the appearance of a semiconductor device, for example.

[0002]

2. Description of the Related Art Generally, the appearance of a semiconductor device is inspected at various stages of a manufacturing process. FIG. 4 shows a conventional visual inspection apparatus. This device includes an imaging device 41 composed of, for example, a CCD camera for imaging the semiconductor device 40, and an image processing device 42 to which a video signal output from the imaging device 41 is supplied and processes an image. The image processing device 42 compares the video signal supplied from the imaging device 41 with a basic pattern indicating the appearance of the semiconductor device, and inspects the appearance of the semiconductor device.

[0003]

By the way, in the above-mentioned conventional visual inspection apparatus, the imaging device 41 is a semiconductor device 4.
0. Therefore, the image picked up by the image pickup device 41 is only the upper surface of the semiconductor device as shown in FIG. Therefore, the items to be inspected are limited to marks and molds, and this visual inspection apparatus cannot be used for inspecting the skew, coplanarity, and the like of the leads provided on the side surfaces of the semiconductor device. For this reason, most of these tests have to be performed by sensory tests such as visual inspection. This sensory test has a problem that the test result is dependent on the uncertainty of the human system, so that the test standard is not uniform and that a defect is overlooked.

[0004] Further, when the appearance inspection is performed after the trimming and forming steps of the lead, the inspection is limited to the inspection of the lead, and other inspections are not performed. For this reason,
There is also a problem that a plurality of appearance inspection steps are required to inspect all appearances.

On the other hand, as a method of automatically inspecting the side surface of the semiconductor device, a method of preparing a plurality of cameras and taking an image of the side surface and the flat surface of the semiconductor device by each camera is considered. However, in this case, a large space is required for installing a plurality of cameras. In addition, when the video signals output from these cameras are processed by one image processing device, a large amount of inspection time is required. Further, in the case where video signals output from a plurality of cameras are processed by a plurality of image processing apparatuses, problems such as an increase in cost of the image processing apparatuses occur.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to take an image of a plane portion and a side surface portion of an inspection object as one screen and process the image so that the external appearance of the semiconductor device is obtained. It is an object of the present invention to provide a visual inspection apparatus capable of accurately inspecting in a short time in a space-saving and cost-saving manner.

[0007]

In order to solve the above-mentioned problems, the present invention provides a plurality of mirrors arranged around a sample and reflecting an image of a side surface of the sample, and arranged above the sample, An imaging unit that captures an image of the upper surface of the sample and an image of a side surface of the sample reflected by the plurality of mirrors; and an inspection that performs grayscale image processing on a video signal supplied from the imaging unit to inspect the appearance of the sample. Means.

[0008] The mirror is set at an angle smaller than 45 ° with respect to the line of sight of the imaging means, and the mirror is disposed above the sample. In addition, the mirror
The angle may be set to 45 ° with respect to the line of sight of the imaging unit.

The imaging means simultaneously captures an image of the upper surface of the sample and an image of the side surface of the sample reflected by the plurality of mirrors, and the inspection means stores a video signal supplied from the imaging means and a video signal stored in advance. The appearance of the sample is inspected by comparing it with the basic pattern.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
1 shows a visual inspection apparatus for a semiconductor device according to an embodiment. In FIG. 1, a semiconductor device 1 as a sample is shown.
Above 1 is an imaging device 12 composed of, for example, a CCD camera.
Is arranged. The semiconductor device 11 and the imaging device 12
A mirror optical system 13 is arranged between the two.

FIG. 2 shows the mirror optical system 13.
The mirror optical system 13 includes, for example, four mirrors 13a, 13b, 13 arranged near four sides of the semiconductor device 11.
c, 13d, and these mirrors 13a to 13d
By 3d, images of the four side surfaces of the semiconductor device 11 are guided to the imaging device 12. These mirrors 13a to 13
d is 45 ° with respect to the line of sight of the imaging device 12 for each reflection surface.
By setting a smaller angle, the mirror optical system 1
3 can be installed above the semiconductor device 11. The imaging device 12 can simultaneously capture an image of the upper surface of the semiconductor device 11 and images of four side surfaces guided via the mirror optical system 13.

An image processing device 14 is connected to the image pickup device 12. The image processing apparatus 14 includes, for example, an interface (I / F) circuit 15, a bus line 16, a microprocessor 17, first and second memories 18, 19,
The display device 20 includes a communication device 21.
The interface circuit 15 is connected to the imaging device 12. A bus line 16 is connected to the interface circuit 15. The bus line 16 is connected to a microprocessor 17, first and second memories 18 and 19, a display device 20, and a communication device 21. The microprocessor 17 controls the entire image processing apparatus 14 as described later. The first memory 18 stores a video signal output from the imaging device 12. The second memory 19 includes, for example, a basic program for controlling the microprocessor 17, a program for various inspections,
And a basic pattern of the upper surface and each side surface of the semiconductor device 11,
The basic pattern of the mark and the like are stored. The display device 20
Displays the inspection result and the like. The communication device 21 exchanges data with another device (not shown).

In the above configuration, the video signal output from the imaging device 12 is stored in the first memory 18 via the interface circuit 15 and the bus line 16. The video signal stored in the first memory 18 is subjected to grayscale image processing. This shading image processing is represented by, for example, binarization processing, multi-level processing, and histogram processing.

Thereafter, a process corresponding to the inspection object is performed. For example, in the case of inspection for irregularities such as voids, scratches, chips, etc. generated in the mold, the microprocessor 17 detects the presence or absence thereof using, for example, histogram-processed data according to instructions of the inspection program, and displays the display device. 20
To be displayed.

In the mark inspection, for example, the binarized data is compared with the basic pattern of the mark stored in the second memory 19. That is, the microprocessor 17 operates according to the instruction of the inspection program.
The video signal stored in the first memory 18 is compared with the basic pattern stored in the second memory 19, and the comparison result is displayed on, for example, the display device 20.

In the inspection for read skew, coplanarity, and the like, for example, binarized or multivalued data is compared with a basic pattern. Inspection for voids, scratches, chips, and the like generated in the mold of the semiconductor device 11 is performed using images of the upper surface of the sample and the four side surfaces. Also,
Inspection of the mark provided on the semiconductor device 11 is performed by the first
The inspection is performed using the image of the upper surface of the semiconductor device 11 stored in the memory 18 of FIG. Further, inspection of lead skew, coplanarity, and the like is performed using images of the sample upper surface and four side surfaces.

The optical path for imaging the upper surface of the sample and the optical path for imaging the side surface of the sample are longer by the amount of the mirror. Therefore, it is necessary to use a lens having a depth of field larger than the optical path difference and an aperture.

As described above, the mirror optical system 13
Has a reflection surface set at an angle smaller than 45 ° with respect to the line of sight of the imaging device 12. For this reason,
Since the image obtained by capturing the side surface of the sample is distorted, it is necessary to perform inspection in consideration of the distortion in the image processing. Therefore, for example, it is necessary to take a countermeasure such that a basic pattern used for image processing is a pattern in consideration of distortion in advance, or the distortion is corrected and then compared with the basic pattern.

According to the first embodiment, the mirror optical system 13 is disposed above and around the semiconductor device 11 as a sample, and the semiconductor device 11 is
The image of the upper surface and the image of the four side surfaces via the mirror optical system 13 can be simultaneously image-processed. Therefore, since a plurality of cameras are not required for capturing and inspecting the image of the side surface, a large space for installing these cameras is not required.

Moreover, images of five surfaces can be simultaneously captured by one image capturing device and taken into the image processing device. Therefore, images are taken by a plurality of cameras and
The image processing time can be reduced as compared with the case where one image processing device is used, and further, the device configuration can be simplified as compared with the case where a plurality of cameras and a plurality of image processing devices are used. Soaring can be prevented.

The mirror constituting the mirror optical system 13 has its reflection surface set at an angle smaller than 45 ° with respect to the line of sight of the image pickup device 12. Therefore, the mirror optical system 13
In a state where is installed above the semiconductor device 11, an image of the side surface of the semiconductor device can be taken. Therefore, since the installation location of the mirror optical system 13 is not limited, it is also possible to image the side surface and the like of the semiconductor device integrated with the lead frame during manufacturing.

FIG. 3 shows a second embodiment of the present invention. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals. In the first embodiment, the mirror optical system 13
Is set at an angle smaller than 45 ° with respect to the line of sight of the imaging device 12. On the contrary,
In this embodiment, the reflection surface of the mirror is set at 45 ° with respect to the line of sight of the imaging device 12. That is, the semiconductor device 11 as a sample is mounted on the stage 31. A mirror optical system 13 is provided around the semiconductor device 11.
Are arranged.

In such a configuration, since the mirror optical system 13 can be arranged around the semiconductor device 11, the image of the side surface of the semiconductor device taken is not distorted. Therefore, image processing can be simplified and inspection accuracy can be improved.

Although the above embodiment has been described with reference to the case where the present invention is used to inspect the appearance of a semiconductor device, the present invention is not limited to the semiconductor device, but can be applied to the appearance inspection of various devices. Needless to say. Of course, various modifications can be made without departing from the spirit of the present invention.

[0025]

As described above in detail, according to the present invention, the image of the flat portion and the side portion of the object to be inspected is captured as one screen and processed, so that the appearance of the semiconductor device can be reduced in space and space. It is possible to provide a visual inspection device capable of accurately and accurately inspecting in a short time at a low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a top view showing a part of FIG. 1;

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional semiconductor device appearance inspection apparatus.

FIG. 5 is a diagram illustrating a conventional captured image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Semiconductor device, 12 ... Imaging device, 13 ... Mirror optical system, 13a-13d ... Mirror, 14 ... Image processing device, 17 ... Microprocessor, 18, 19 ... 1st, 2nd memory, 20 ... Display device.

Claims (6)

[Claims] 1. A plurality of mirrors disposed around a sample and reflecting an image of a side surface of the sample, and an image of a top surface of the sample disposed above the sample and reflected by the plurality of mirrors An appearance inspection apparatus comprising: an imaging unit that captures an image of a side surface of the image forming apparatus; and an inspection unit that performs grayscale image processing on a video signal supplied from the imaging unit and inspects an appearance of the sample. 2. An appearance inspection apparatus according to claim 1, wherein said mirror is set at an angle smaller than 45 ° with respect to the line of sight of said imaging means. 3. The visual inspection device according to claim 2, wherein the mirror is disposed above the sample. 4. The visual inspection apparatus according to claim 1, wherein the mirror is set at 45 ° with respect to a line of sight of the imaging unit. 5. The external appearance according to claim 1, wherein said inspection means inspects the external appearance of said sample by comparing a video signal supplied from said imaging means with a basic pattern stored in advance. Inspection equipment. 6. The visual inspection apparatus according to claim 1, wherein said imaging means simultaneously captures an image of the upper surface of the sample and an image of a side surface of the sample reflected by the plurality of mirrors.