KR100251482B1 - Pcb unit examining apparatus and method - Google Patents

Abstract

PURPOSE: An apparatus and a method for checking a PCB(Printed Circuit Board) substrate are provided to check a state where components of a PCB substrate are packaged in a more fast and exact manner. CONSTITUTION: A PCB substrate checking apparatus has a plurality of sample soldering parts. An image judging part(11) judges a state of the sample soldering part by realizing the sample soldering parts of the PCB substrate(45) into a flat image through an optical image pick-up unit. A height checking part(21) checks quality due to a height difference by realizing the sample soldering parts of the PCB substrate into a three dimensional image. A control part judges the quality by checking, at the first check, the state of the sample soldering parts of the PCB substrate(45) through either side among the image judging part(11) and the height checking part(21) and, checking, at the second check, the sample soldering parts, which are judged to have a low reliability according to the first check.

Description

PCB board inspection device and inspection method

The present invention relates to an inspection apparatus and inspection method of a PCB substrate.

A film integrated circuit for forming a printed circuit board (PCB) substrate for an electronic product is a circuit in which a plurality of circuit elements are formed by a thick film and a thin film on an insulated substrate, and the elements are interconnected by a film to form a circuit. An integrated circuit is a circuit in which a semiconductor device and individual passive components are combined with a film integrated circuit. The technology for forming such a hybrid integrated circuit is referred to as board level packaging technology, and may be classified into an insertion mount, a surface mount, a hybrid mount, and the like according to a mounting method.

Among the component connection technologies of hybrid integrated circuits, generally used are sulfuric acid contact and compression. In the crimping method, the metals to be joined are pressed and plastically deformed to bond together by shear stress, and the mutual bonding is performed. The sulfuric acid bonding method is a method of melting and solidifying a low melting point braze material between metals to be joined and solidifying them. Among these methods, a sulfuric acid method, which can be easily bonded at a relatively low price, is generally used.

3 is a partial perspective view of a PCB substrate on which an IC chip is mounted by a sulfuric acid contact method, that is, a soldering method. By the way, as shown in Fig. 5, the lead 43 of the component 41 and the pad (not shown) on the substrate are formed by the soldering method. In addition, depending on the amount of the initial sample lead or the heating conditions during soldering, sample solder portions of a wide variety of shapes are formed. The surface of the soldering portion 47 is formed as a mirror surface, so that the soldering portion 47 of the PCB substrate 45, through the PCB substrate inspection apparatus to be described later, the quality state, that is, misplacement, positional deviation In case of defects, the product will be automatically inspected.

4, which is not described, is a side view of FIG. 3, in which the soldering state of the IC chip lead 43 normally soldered onto the PCB substrate is enlarged.

PCB board inspection apparatus, various kinds are proposed according to the method of inspecting the PCB substrate, Figure 6a and 6b is a schematic configuration diagram of a PCB substrate measuring apparatus using a conventional CCD camera. The conventional PCB board inspection apparatuses 51 and 57 using the CCD camera 53 are the illumination system 55 which illuminates the mirror surface soldering part 47, and the soldering part 47 illuminated by this illumination system 55. And an imaging CCD camera 53 for sending an image to the vision processing unit (not shown) for imaging.

Since the light incident from the illumination system 55 toward the soldering portion 47 is reflected in a constant direction with respect to the normal of the surface, the height or the slope distribution of the soldering surface is appropriately reflected and correspondingly reflected by the illumination having a known direction. The light can be measured by the CCD camera 53 confirming recognition. At this time, since the image of the soldering portion 47 is implemented in the vision processing portion in a planar manner, the operator can visually recognize and inspect the quality of the soldering portion 47 imaged in this planar manner. It can be automatically inspected by the learning of the control unit. The inspection by the learning of the control unit is automatically performed through an adaptive learning mechanism according to the programmed learning process of the neural network classifier, which does not show the height distribution or the distribution of the inclination, which are expressed in the appearance of the soldering part 47. Will be analyzed.

By the way, in the PCB board inspection apparatuses 51 and 57 by such a CCD camera, since the quality of the soldering part 47 is judged based on the shape implemented planarly, the surface inclination degree of the soldering part 47 and the distribution of height are measured. There is a limit to detailed inspection. That is, the planar image implemented through the CCD camera 53 determines whether the soldering state of the component is positive or not, based on the existing programmed model or rule. At this time, the soldering unit 47 and the lighting system ( If the contrast with the background illuminated by 55 is similar, there is no difference in the characteristic values according to the height or the inclination of the soldering part 47, so it is very difficult to select the quality. Therefore, in recent years, a PCB substrate inspection apparatus using a laser has been proposed to precisely inspect the quality of the soldering portion 47 and accurately determine the quality thereof.

The PCB substrate inspection apparatus using such a laser emits laser light on the surface of the soldered portion to be inspected, receives the reflected laser light reflected from the surface of the soldered portion, and realizes three-dimensional fluorescence having a wavelength unique to the material. It is an apparatus for inspecting the surface state of a soldering part by analyzing on the basis of. Unlike the natural light, the laser light has a narrow and large energy focused in a narrow range, and since it has a strong straightness and no waveiness, it has a side effect of reducing the inaccuracy of the boundary of the object due to diffraction generated when using natural natural light. You can get it.

By the way, in the conventional PCB inspection apparatus using a laser, there is an advantage that can be inspected in detail irrespective of the color of the soldering portion implemented in the three-dimensional image, but it takes a lot of time to obtain the information, There are many problems in the practical use of the device.

Accordingly, an object of the present invention, in consideration of the problems of the PCB substrate measuring device using a conventional CCD camera and the PCB substrate measuring device using a laser, PCB board inspection that can inspect the mounting state of the PCB board more quickly and very accurately. It is to provide an apparatus and an inspection method.

1 is a schematic configuration diagram of a PCB substrate measuring apparatus according to the present invention,

2 is a schematic control block diagram of a PCB substrate measuring apparatus using a laser constituting the height inspection unit of the present invention,

3 is a partial perspective view of a PCB substrate on which an IC chip is mounted;

4 is an enlarged side view of FIG. 3 showing a soldering state of an IC chip lead normally soldered onto a PCB substrate;

5 is a partial cross-sectional view of FIG. 3 showing a bad sample solder on a PCB substrate;

6A and 6B are schematic configuration diagrams of a PCB substrate measuring apparatus using a conventional CCD camera.

<Description of the symbols for the main parts of the drawings>

3: X-Y Table 5: Transfer Conveyor

11: Image Determination Unit 13: CCD Camera

15: lighting system 17: split

21: height inspection part 41: parts

43: Lead 45: PCB Board

47: soldering part

According to the present invention, there is provided a PCB substrate inspection method having a plurality of sample soldering portions, comprising the steps of: implementing a sample soldering portion of a PCB substrate to be inspected into a planar image through optical imaging means; First inspecting the state of the sample soldering portion based on the planar image of the sample soldering portion; Sequentially implementing a three-dimensional image of the sample solder having low reliability by the first inspection; It is achieved by the PCB substrate inspection method comprising the step of secondaryly checking the state of the sample solder portion based on the three-dimensional image of the sample solder portion, and determining whether or not defective.

Here, the first inspection step may further comprise the step of classifying the quality of the sample soldering portion to a predetermined grade.

On the other hand, according to another field of the present invention, the object is, in the PCB substrate inspection apparatus having a plurality of sample soldering portion, the image to implement the sample soldering portion of the PCB substrate as a planar image through the optical imaging means to inspect the quality A judgment unit; A height inspection unit which implements the sample soldering portion of the PCB substrate in a three-dimensional image and inspects the quality due to the height difference; The control unit which primarily checks the state of the sample soldering portion of the PCB substrate through any one of the image determination portion or the height inspection portion, and secondly checks the sample soldering portion of low reliability by the first inspection It is achieved by a PCB substrate inspection device comprising.

Wherein the primary inspection is inspection of the sample soldering portion by the image determining portion; The secondary inspection is preferably configured by the inspection by the height inspection unit.

At this time, the image determining unit includes: a CCD camera for optically imaging the sample soldering portion of the PCB substrate; It can be simply configured as a vision processing unit for implementing a planar image of the image from the CCD camera, the height inspection unit, laser measuring means; It may be configured to include a vision processing unit for implementing the output from the laser measuring means in a three-dimensional image.

And, it is preferable to further comprise a lighting means for illuminating the sample soldering portion of the PCB substrate.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a PCB substrate measuring apparatus according to the present invention. As can be seen from this figure, the present PCB substrate measuring apparatus 1 includes a transfer conveyor 5 to which the PCB substrate 45 to be inspected is transferred, and a PCB substrate 45 above the transfer conveyor 5. The image determination unit 11 and the height inspection unit 31, which are provided side by side in the conveying direction of the support, and the PCB substrate 45 to be inspected are supported and disposed below the image determination unit 11 or the height inspection unit 31. It has an XY table 3. Images from the image determining unit 11 and the height inspection unit 31 are each implemented through a vision processing unit (not shown).

The image determining unit 11 includes an illumination system 15 for illuminating the soldering portion 47 of the PCB substrate 45 fixedly supported on the XY table and the PCB substrate 45 illuminated by the illumination system 15. It consists of an imaging part which image | photographs the soldering part 47 of this. The imaging section is composed of a pair of CCD cameras 13 provided in the standing direction and a split section 17 for branching out the optical images from the PCB boards 45 to the respective CCD cameras 13. Hereinafter, the main camera 13a is disposed downwardly above the fixed PCB substrate 45 for ease of description, and the one provided in parallel to one side of the main camera 13a will be referred to as the sub camera 13b. do. The main camera 13a and the sub-camera 13b are composed of different magnifications, and the sub-camera 13b is composed of a high magnification camera for microscopic inspection.

The split part 17 is arranged below the beam splitter 17a and the sub-camera 13b vertically below the main camera 13a on the optical path from the PCB board 45, so that the beam splitter ( It is comprised by the reflecting mirror 17b which reflects the optical image from 17a toward the sub-camera 13b. The beam splitter 17a reflects a part of the incident light beam and transmits another part thereof, and is disposed in the barrel with a predetermined inclination angle with respect to the optical path from the solder portion 47 of the PCB substrate 45, As shown by arrows in the figure, the optical image from the soldering portion 47 is transmitted to the main camera 13a and reflected at the sub-camera side. Thereby, the optical image from the soldering part 47 of the PCB board 45 supported by the XY table 3 is recognized by the relatively low magnification main camera 13a and the high magnification sub camera 13b, respectively. The processing unit performs image processing on two screens.

On the other hand, the illumination system 15 is comprised by circular color lamps arranged in layers on the same axis of the main camera 13a. These color lamps are composed of high frequency fluorescent lamps, and may be configured to irradiate various colors for each layer. Since they are different in height and diameter with respect to the PCB substrate 45 fixed to the lower side, the reflection angles from the soldering portion 47 are different according to the incident light, and therefore, each CCD camera 13 has a soldering portion. It is possible to obtain images of different colors according to the surface inclination degree and the height of (47).

On the other hand, the height inspection part 21 is arrange | positioned on the downstream side of the image determination part 11 in a parallel manner. 2 is a schematic control block diagram of a PCB substrate measuring apparatus using a laser constituting the height inspection unit. As can be seen from this figure, the height inspection part 21 has a sensor part 23 composed of a laser light emitting part 25 and a laser light receiving part 29, and emits laser light and reflects the laser from the surface of the solder part. The controller 35 is configured to detect light and recognize the image as an image through the vision processor 37. The control unit 35 emits laser light toward the surface of the soldering unit 47 through the light emitting element 27 of the laser light emitting unit 25, and the emitted laser light is incident on the surface of the soldering unit 47. According to the principle of reflection is reflected in each direction, at this time, the light receiving element 31 of the laser receiving unit 29 receives the reflected laser light.

The output from the laser sensor unit 23 is converted into a signal that can be recognized by the control unit 35 via the comparator 33 or the like and output. Then, the control unit 35 receives this output, and implements the distribution of the inclination or the height of the soldering unit 47 to the vision processing unit 37 as a 3D image. Unlike natural light, laser light can be focused in a narrow and large energy in a narrow range, so that it is possible to locally irradiate the surface of the soldering part 47 to perform a limited fine inspection. In addition, since the reflected laser light reflected on the surface of the soldering part 47 emits fluorescence having a wavelength specific to the material, when the light is analyzed, the quality state of the soldering part surface can be easily inspected using the height difference. do. In addition, since the laser light has a strong straightness and no waves, the side effect of reducing the inaccuracy of the boundary of the object due to diffraction generated when using natural natural light can be obtained.

On the other hand, the image implemented as described above, as described with respect to FIG. 6, the user can determine whether or not by visual recognition, on the other hand, the adaptive learning method (Adaptive learning mechanism) according to the programmed learning process of the neural network classifier Automatic analysis through

In the PCB substrate measuring apparatus having such a configuration, when the PCB substrate 45 to be inspected through the conveying conveyor 5 is transferred and supported on the XY table, the control unit 35 first determines the XY table 3 by image determination. It moves to the lower side of the part 11. Then, when the soldering portion 47 of the PCB substrate 45 is illuminated through the illumination system 15, the reflected light from the soldering portion 47 is incident on the main camera 13a and the sub-camera 13b, respectively. Thus, the image from each camera is implemented in the vision processing unit 37 as a planar image.

The image of the soldering portion 47 of the PCB substrate 45 implemented as described above is classified by the operator visually to classify the quality, or does not show the height distribution or the distribution of the slope appearing in the appearance of the soldering portion 47. The neural network classifier automatically analyzes the adaptive learning mechanism according to the programmed learning process. Inspection of soldering part quality by such neural network classifier is described in detail in patent applications Nos. 95-61661 filed by the present applicant. At this time, the information about the soldered portion which is difficult to trust among the classified soldered portions is stored in the memory.

On the other hand, a PCB substrate having a soldering portion which is difficult to be relied upon is arranged under the height inspection section 31 by the control of the X-Y table by the control section 35. Then, based on the information stored in the memory, the laser light is sequentially emitted through the light emitting element 27 of the laser light emitting portion 25 to the soldering portion 47 which is difficult to trust, and the light receiving water of the laser light receiving portion 29 is obtained. The laser beam receives the reflected laser light reflected from the surface of the soldering portion 47 through the ruler 31. Then, in the vision processing unit 37, a three-dimensional image of the soldering unit 47 through the laser light is implemented, the operator or the control unit 35 of the PCB substrate 45 is difficult to trust through this implemented image. The quality of the soldering part 47 can be judged as good or bad.

As described above, according to the PCB board inspection apparatus and the PCB board inspection method of the present invention, the soldering part of the PCB board is primarily inspected by the planar image implemented by the CCD camera of the image determination section, and then the detected reliability Since the soldering part of the PCB board, which is difficult to do, can be secondarily inspected by the height inspection part using a laser beam, it is possible to inspect the mounting state of the PCB board very accurately and to inspect it relatively quickly. do.

Claims (6)

In the PCB substrate inspection method having a plurality of sample soldering portion, Implementing the sample soldering portion of the PCB substrate to be inspected into a planar image through optical imaging means; Firstly classifying the quality of the baby sample soldering portion into a predetermined grade according to a state by first inspecting the sample soldering portion based on a planar image; Implementing a three-dimensional image by height inspection on the sample solder having low reliability by the first inspection; And secondly checking a state of the sample soldering portion based on the three-dimensional image of the sample soldering portion and determining whether or not the defective soldering portion is determined. In the PCB board inspection apparatus having a plurality of sample soldering portion, An image determining unit configured to determine a state of the sample soldering portion by implementing the sample soldering portions of the PCB substrate through a planar image through optical imaging means; A height inspection unit which implements the sample soldering portion of the PCB substrate in a three-dimensional image and inspects the quality due to the height difference; The control unit which primarily checks the state of the sample soldering portion of the PCB substrate through any one of the image determination portion or the height inspection portion, and secondly checks the sample soldering portion of low reliability by the first inspection PCB board inspection apparatus comprising a. The method of claim 3, The primary inspection is inspection of the sample soldering portion by the image determining portion; The secondary inspection is a PCB substrate inspection device, characterized in that the inspection by the height inspection unit. The method according to claim 3 or 4, The image determination unit, A CCD camera for optically imaging the sample soldering portion of the PCB substrate; PCB inspection apparatus comprising a vision processing unit for implementing a planar image of the image from the CCD camera. The method according to claim 3 or 4, The height inspection unit, Laser measuring means; PCB inspection apparatus comprising a vision processing unit for implementing the output from the laser measuring means in a three-dimensional image. The method of claim 3, PCB inspection apparatus further comprises a lighting means for illuminating the sample soldering portion of the PCB substrate.

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