JPH0377008A - X-ray transmission image signal detector and soldering inspecting system by x-ray transmission image signal - Google Patents

Abstract

PURPOSE:To allow the exact inspection of a soldered section by adding a two-dimensional moving mechanism to an X-ray detector and actuating this mechanism as a panning or tilting mechanism, thereby detecting the panned or tilted X-ray transmission signal free from image distortions. CONSTITUTION:A sample 2 is mounted on a sample stage 3' and is moved in parallel by two axes, x and y to be positioned for inspection. An X-ray source is moved in the direction perpendicular to the sample 2 by an X-ray stage 9 and determines the magnification of the resulted X-ray image. The X-ray detector 4, which is positioned below the sample 2 and is mounted on a detector stage 8, moves in parallel by the two axes, x, y, within the plane parallel with the sample 2 and relatively inclines the X-ray axis and the normal direction of the sample 2. The positions of the X-ray source and the detector 4 are first moved by the stages 9 and 8 in order to set the detection magnification and the angle of inclination of the optical axis and the sample 2 by the control of a system control section 7. The sample 2 is then mounted on the stage 3' and is moved to the position where detection is desired to be made. The X-ray is exposed to this sample 2 and the image obtd. by the detector 4 is compared with the data on non-defectives in an image processing section 5, by which the normal/ defective conditions are decided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an Xli path image signal detection device and a method for inspecting soldered parts of a printed circuit board or the like using an X-ray transmission image.

[Conventional technology]

Conventionally, a soldering inspection device using an X-ray transmission II image is a soldering inspection device using a second inspection method as described in the Japanese Patent Publication No.
11IIIL shown in the figure. In the figure, 1 is xla
2 is a printed circuit board with soldered parts (test sample)
, 5 is a sample stage, 4 is an xl/A detector, 5 is an ms processing section, 6 is a stage control section, and 7 is a system control section. x irradiated from X-ray source 1! I passes through the test sample,
The transmitted X and m1ll of the test sample are detected by the X-ray detection ls4. The solder row portion of the printed circuit board 2 contains lead, but lead has a larger X-ray absorption coefficient than the other materials that make up the printed circuit board, such as the base portion and the steel wire portion. Since the amount of absorption is proportional to the logarithm of the distance transmitted,
The thickness of the soldered portion at each point on the print substrate 2 can be detected from the line-transmission image. The image processing unit 5 compares this with a predetermined standard for a non-defective soldered part to determine whether the soldered part is good or bad.

When components are mounted on both sides of the printed circuit board 2, as shown in FIG.
If the board 2 is placed perpendicular to the optical axis, the soldered parts 2M and 24 of the upper and lower components 21.22 will overlap, and the detector 4 will receive a composite image of both soldered parts 25.24. It is detected, and correct judgment cannot be made.

Therefore, as shown in Figure 4, the printed circuit board (test sample) 2
It is necessary to inspect by tilting the board so that the upper and lower soldered parts 23 and 24 do not overlap. Therefore, the sample stage 3 requires a five-axis stage for tilting the sample 2 (L4 (punt and tilt)) in addition to two stages for determining the magnification of the XY stage that determines the inspection position.

[Problem to be solved by the invention]

The above-mentioned conventional technology is expensive because as many as five axes are concentrated on the sample stage, making the deer 1 mechanically complex, and the weight increases, making it difficult to move the sample at high speed and brake. Also,
The inclination of the sample stage poses a problem in that as the sample becomes larger, interference occurs between the X-ray source or X-ray detector and the sample stage, making it impossible to inspect large samples.

The object of the present invention is to provide an X-ray transmission image detection device and a soldering part inspection method using XII transmission images, which are capable of separately detecting X-ray transmission images of upper and lower soldered parts without overlapping without causing interference. Our goal is to provide the following.

An object of the present invention is to provide a method for inspecting soldered parts using xlI transmission images, which makes it possible to accurately inspect soldered parts by detecting pan or tilted X-ray transmission image signals without image distortion. It's about doing.

[Means to solve the problem]

That is, in order to achieve the above object, the present invention adds a two-dimensional movement mechanism to the X-ray detector 4, replacing the sample tilting mechanism, that is, panning or tilting mechanism, among the stage movement axes concentrated on the sample stage. This is a sample stage with a cylindrical structure.

[Effect]

With the above configuration, it is possible to inspect large samples by tilting the sample stage tilting mechanism.

Furthermore, by moving the X-ray detector two-dimensionally in a plane parallel to the inspection sample, the O
This makes it possible to detect pan or chill (XM transmission iii) signals without image distortion without having different magnifications in each part.

〔Example〕

The present invention will be explained below based on embodiments shown in the drawings. First, the principle of the present invention will be explained based on FIG.

The sample stage 3 is a stage having an 02 axis in the same plane as the inspection sample 2, and positions the inspection position. The X-ray detector 4 is placed on a detector stage 8 having an x72 axis in the same plane as the sample 2. If the detector 4 is placed on the detector stage 8 at a position shifted from directly below the X-ray source, the test sample 2 will be tilted relative to the straight line connecting the X-ray source 1 and the detector 4, that is, the optical axis. Sample stage S to be placed
An X-ray transmission image signal equivalent to a tilted (pan or chill) X-ray image signal is obtained.

Furthermore, by moving the detector 4 within a parallel image with the sample 2, the magnification at both ends of the field of view remains constant at M:B''C:D, so that image distortion does not occur.

Furthermore, X. Place the X-ray source 1 on the second stage 9,
The magnification can be changed by moving the image vertically. With all of the above, sample stage 5 is X! Since it can be configured with only two axes, the mass can be reduced and the sample can be moved and positioned at high speed.

FIG. 1 shows an embodiment of an apparatus for inspecting soldered parts using X-ray transmission images according to the present invention.

In the figure, 1 is an X-ray source, 2 is an inspection sample such as a printed circuit board with electronic components mounted, 3 is a sample stake, 4 is an X-ray detector, and 5
is an image processing section, 6 is a stage control section, 7 is a system control section, 8 is a detector stage, and 9 is an X-ray source stage.

Sample 2 is mounted on sample stage 5, and sample stage 3
The X-ray source 1 is positioned above the sample 2, and is moved perpendicular to the sample 2 by the X-ray source stake 9. The magnification of the obtained xls image is determined by ε. The xm calm detector A is located below the sample 2, can be mounted on the detector stage 8, and has a surface parallel to the sample 2 x *
72 axes, and the color in the normal direction of the X-ray optical axis ε sample 2 can be relatively adjusted.

In the inspection, the X-ray source and the X-ray detector 4 are moved xD to the X-ray source stage 9 and the detector stage 8 in order to set the inclination magnification and the optical axis of the sample 2ε.

Next, the sample 2 is mounted on the sample stage 3, and after the sample is moved by the sample stage 3 to the location where black inspection is desired, it is exposed to X-rays, and an X-ray degraded image of the sample is detected by the X-ray detector 4. , the image processing unit 5 compares the color of the non-defective data and determines the distortion of the soldered part. The sequence and inspection position of the sample are run-rolled by the system control unit 7, and the X-ray detector 4
After completing the inspection of the specified broken solder joint within the field of view, move the sample stage 5 and do not change the inspection of another solder joint.

In this example, the position of the X-ray source was moved to change the magnification, but the sample 2. ! :m It is also possible to add a rectangular movement axis in the same direction and move the X-ray detector in the direction perpendicular to the sample 2.

Additionally, in this example, in order to tilt the XMi optical axis and the sample 2ε, the detector 4 was moved parallel to the sample, but
Add a shaft metal 18 to the radiation source stage 9 that can be moved in parallel within the sample ε-flat Ti blood, and move the X-ray source to the side D of the X-ray detector.
1:4 good.

〔Effect of the invention〕

As explained above, according to the present invention, the mechanism of the sample stake can be simplified, so the sample stake can be manufactured at low cost, the sample stake is lightweight, so high-speed movement and positioning can be performed, and furthermore, the sample stake can be moved and positioned at high speed. This makes it possible to test even large samples. In addition, according to the present invention, it is possible to obtain an X-ray transparency image correction with no image distortion, and it is possible to improve the inspection accuracy and reliability of soldered parts. be effective.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram of a conventional method, and Fig. 5 is a diagram illustrating the main components of double-sided mounting board inspection. FIG. 4 is a diagram for explaining an inward mounting board inspection method, and FIG. 5 is a diagram for explaining the present invention. 1...-X [! l source, 2... Printed circuit board (inspection sample) %S.
......Sample stage, 4...・Stage control section, 7...
. . . System control unit, 8 . . . Detector stage, 9 . . . X-ray source stage. 5...6 formula 1'F stage ゛' 4...

Claims (4)

[Claims] 1. An X-ray source; an X-ray detector that detects a transmission image signal of X-rays irradiated from the X-ray source to the sample; the sample is moved in parallel within the sample image; An X-ray transmission image signal detection device, characterized in that the X-ray detector is moved in parallel to detect a pan or tilt transmission image signal of the sample from the X-ray detector. 2. 2. The X-ray transmission image signal detection apparatus according to claim 1, wherein said X-ray source is configured to be able to move said sample in a vertical direction, and to enable reliability correction. 3. 3. The X-ray transmission image signal detection apparatus according to claim 1, wherein the sample is a printed circuit board on which electronic components are mounted by soldering, and the apparatus is configured to inspect the solder joints. 4. an X-ray source, and an X-ray detector that detects an X-ray transmission image signal of the soldered part irradiated by the X-ray source to a board having the soldered part, the X-ray source or the X-ray detector A soldering inspection method using an X-ray transmission image, characterized in that the soldering state is inspected by detecting a pan or tilt transmission image signal of the soldering part by moving it parallel to the base slope in an image parallel to the base slope.