JP2001004561A - Board inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extract the mounting image of electronic parts and easily discriminate whether a connection state is conforming or not by picking up an image when X rays are transmitted before and after mounting electronic parts on a board. SOLUTION: A raw board 20 before an IC 21 is mounted is mounted on an inspection stage, and an X-ray transmission image is picked up by a CCD camera. When X rays are transmitted through the board 20, they are attenuated by the thickness of the board 20. The board 20 where the IC 21 with a ball- shaped terminal is mounted on the lower surface of a package as a sample, the image of X rays is picked up by a camera, and the X rays are attenuated by the thickness of the board 20 and the IC 21. By subtracting the image of the ray board 20 from the image of the board 20 where the IC 21 is mounted, the solder image of the IC 21 can be obtained, and the amount of attenuation of X rays of only the IC 21 can be obtained. The X-ray transmission image of the board 20 before and after the IC 21 is mounted is obtained and the solder image of the IC 21 can be obtained according to the difference in both of them, thus relatively easily discriminating the conformity or non-conformity of the packaging of the IC 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a board inspection apparatus, and more particularly, to an X-ray CSP (Chip Size Package) and a BGA.
The present invention relates to a board inspection apparatus for inspecting the quality of mounting on a board on which an IC such as a (Ball Grid Array) is mounted.

[0002]

2. Description of the Related Art X-ray CSPs and BGAs have a large number of terminals, and a large number of terminals are arranged on the lower surface of a package. It is very difficult to check whether they are present or not. In the case of other electronic components, it is very easy to visually inspect whether or not they are properly soldered to the terminals of the board. On the other hand, the terminals of the X-ray CSP and the like are provided on the lower surface of the package. After soldering to the terminals, it is difficult to visually inspect.

For this reason, when an operation failure occurs after performing an operation test, it is determined for the first time that the package is not properly attached to the substrate, and the package is removed from the substrate.
A very inefficient work of re-soldering was forced.

There is also a method of transmitting X-rays to the substrate and determining the quality of the soldering state from the transmitted image, but there is a problem that the determination of the quality based on the transmitted image can be performed only by a skilled operator.

[0005] Therefore, the main object of the present invention is to provide X
It is an object of the present invention to provide a board inspection apparatus which can easily detect a required portion of solder by utilizing the principle of wire transmission.

[0006]

The invention according to claim 1 is
A board inspection apparatus for inspecting a connection state of an electronic component mounted on a substrate by transmitting X-rays to the substrate, the image being obtained by transmitting the X-rays to the substrate before mounting the electronic component on the substrate. Then, the mounting image of the electronic component is extracted from the difference between the image when the X-ray is transmitted to the board after the electronic component is mounted, and the connection state is determined.

According to the second aspect of the present invention, there is further provided a fluorescent plate for projecting a transmitted image by X-rays transmitted through the substrate, a mirror for reflecting the image projected on the fluorescent plate, and an image pickup means for taking an image reflected by the mirror. And an image processing means for performing pass / fail determination based on the output of the imaging means.

[0008]

FIG. 1 is a diagram showing the entire configuration of a substrate inspection apparatus according to the present invention. In FIG. 1, an X-ray generator 3 is held on a left side of a pedestal 1 by a jack 2, and the X-ray generator 3 is controlled by a controller 4. Further, in front of the X-ray generator 3 on the pedestal 1, an X stage 5 that can move in the horizontal direction as an inspection stage and a Y stage 6 that can move in the vertical direction are provided, so that the sample 7 can be moved vertically and horizontally. It can be moved to.

Further, a housing 8 is provided in front of the sample 7, and a fluorescent plate 9, a mirror 10, a CCD
A camera 11 is arranged. The X-rays generated by the X-ray generator 3 pass through the sample 7, and a transmitted image of the sample 7 is displayed on the fluorescent screen 9. This image is reflected at 90 ° by the mirror 10 and CC
The image is captured by the D camera 11.

Usually, when an X-ray transmission image is obtained, an X-ray Im
Although an age intensifier is used, since this element is generally expensive, an image intensifier is used in the embodiment of the present invention.
The fluorescent plate 9 is used without using an ifier. However, if the image reflected on the fluorescent screen 9 is taken by the CCD camera 11 as it is, the X-rays passing through the fluorescent screen 9 will be reflected by the CCD camera 1.
1 is adversely affected. Therefore, in this embodiment, the image reflected on the fluorescent screen 9 is reflected by the mirror 10 so that the CCD camera 11 is not adversely affected by the leaked X-rays, and the reflected image is captured by the CCD camera 11. CCD
The output of the camera 11 is input to the video board 12, subjected to image processing, and displayed on the display of the personal computer 13.

FIG. 2 is a view for explaining a method for inspecting the quality of a substrate on which an IC is mounted using the apparatus shown in FIG. As shown in FIG. 2A, as a sample 7 shown in FIG. 1, a raw substrate 20 before an IC 21 is mounted is first mounted on an inspection stage, and an X-ray transmission image is obtained by a CCD camera 11.
Is imaged. When X-rays are transmitted through the substrate 20,
X-rays are attenuated by the thickness of the substrate 20. This attenuation amount is expressed by the following equation (1).

[0012]

(Equation 1)

Next, as shown in FIG. 2B, a substrate 20 on which an IC 21 provided with ball-shaped terminals on the lower surface of a package such as a BGA is mounted as a sample 7, and an X-ray Is captured by the CCD camera 11. In this case, the X-rays have a thickness
Attenuated by C21. The equation is shown in equation (2).

[0014]

(Equation 2)

Therefore, the substrate 2 on which the IC 21 is mounted
If the image of the raw board 20 is subtracted from the image of 0, IC2
One solder image can be obtained. The amount of X-ray attenuation only by the IC 21 is expressed by the following equation (3).

[0016]

(Equation 3)

As described above, according to this embodiment, I
An X-ray transmission image of the board 20 before and after mounting the C21 is obtained, and a solder image of the IC 21 can be obtained based on a difference between the two, so that the quality of the mounting of the IC 21 can be determined relatively easily.

This determination process can be executed by the video port 12 shown in FIG. Then, an image when the IC 21 is a good solder image is registered in advance,
It is sufficient to determine whether or not the solder image is non-defective by comparing the calculated solder image.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0020]

As described above, according to the present invention, images of X-rays transmitted before and after mounting an electronic component on a substrate are captured, and the mounting image of the electronic component is determined by the difference between the two. It is possible to relatively easily determine the quality of the connection state by extracting.

[Brief description of the drawings]

FIG. 1 is a diagram showing the overall configuration of a board inspection apparatus according to the present invention.

FIG. 2 is a diagram for explaining a method for detecting the quality of a substrate on which an IC is mounted by using the apparatus shown in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 pedestal 2 jack 3 X-ray generator 4 controller 5 X stage 6 Y stage 7 sample 8 housing 9 fluorescent plate 10 mirror 11 CCD camera 12 video port 13 personal computer 20 substrate 21 IC

Claims (2)

[Claims] An apparatus for inspecting a connection state of an electronic component mounted on a substrate by transmitting X-rays through the substrate, wherein the electronic component is mounted on the substrate before mounting the electronic component on the substrate. Extracting a mounting image of the electronic component based on a difference between an image when the X-ray is transmitted and an image when the X-ray is transmitted to the substrate on which the electronic component is mounted, and determining whether the connection state is good or bad; A substrate inspection apparatus characterized by the above-mentioned. 2. A fluorescent plate for projecting a transmitted image by X-rays transmitted through the substrate, a mirror for reflecting an image projected on the fluorescent plate, an imaging unit for imaging an image reflected by the mirror, 2. The board inspection apparatus according to claim 1, further comprising: an image processing unit for performing the pass / fail determination based on an output of the imaging unit.