KR101144749B1 - Method for inspecting joint error of an element formed on a printed circuit board - Google Patents

Abstract

In order to inspect the defect of the connection state of the device mounted on the substrate, the device to be inspected is selected and the type of the device is determined. Next, the inspection method according to the type of the device is selected, and then the terminal height measurement method is performed or the body height measurement method is performed according to the selected inspection method. Accordingly, it is possible to easily and accurately determine whether the connection state depends on the type of device mounted on the substrate.

Description

METHODS FOR INSPECTING JOINT ERROR OF AN ELEMENT FORMED ON A PRINTED CIRCUIT BOARD}

The present invention relates to a defect inspection method of a device, and more particularly to a defect inspection method of a device mounted on a printed circuit board.

In general, at least one printed circuit board (PCB) is provided in an electronic device, and elements of various shapes are mounted on the printed circuit board.

The device may have a variety of shapes and types, a typical example of the device being a body comprising a drive circuit and a plurality of terminals protruding from the body. In general, terminals of the device are electrically connected to the driving circuit inside the body, and are electrically connected to each other by soldering with pads formed on a base substrate.

As described above, defects of elements having various shapes and types may exist in various forms, but a large number of defects in a connection state in which terminals of the elements formed on a substrate are connected to each other are occupied in large numbers.

Conventionally, in order to determine whether the connection state of the terminal is defective, a method of taking and analyzing a two-dimensional picture of the device has been mainly utilized. However, such a two-dimensional inspection method has a limitation in accurately inspecting the connection failure of the device.

Therefore, there is a need for a method for easily and accurately confirming whether a device is in a bad connection state.

Accordingly, the present invention has been made in view of the above problems, and the problem to be solved by the present invention is to provide a defect inspection method of an element which can easily and accurately determine the quality of the connection state of the element mounted on the substrate. will be.

In the defect inspection method of a device according to an exemplary embodiment of the present invention, an image obtained by irradiating light generated in a plurality of directions to a device including a body and at least two terminals on one side of the body Examine the defect of the device using the data. First, a region corresponding to terminals of a device including a body and a plurality of terminals is separately set as a separate region of interest independent of the region corresponding to the body of the device. Then, the height of each of the terminals of the device located in the region of interest is measured to obtain height data of the terminals. Next, the coplanarity of the terminals of the device is examined using the obtained height data. Subsequently, as a result of the inspection, when the terminals of the device are located on the same plane, it is determined as good, and when not located on the same plane, it is determined as bad.

In an embodiment, the checking whether the terminals of the device are located on the same plane using the obtained height data may include: inclination formed by at least two first terminals formed on the first side of the body; Checking whether a difference exceeds a preset ipsilateral slope allowance, checking whether a difference between a maximum height and a minimum height of the first terminals exceeds a preset ipsilateral height difference allowance, and The method may include at least one of checking whether a difference between each height and an average height exceeds a predetermined average height allowance. At this time, the step of checking whether the terminals of the device are located on the same plane by using the obtained height data, the slope formed by at least two or more second terminals formed on the second side of the body is the same side Checking whether a slope allowance is exceeded, checking whether a difference between the maximum height and the minimum height of the second terminals exceeds the ipsilateral height difference requirement, and each height and average height of the second terminals. It may further comprise at least one of the step of checking whether the difference is greater than the average height allowance.

In an embodiment, the method for inspecting a failure of the device may include setting a region corresponding to the body of the device as a region of interest and obtaining height data of at least two or more points, using the obtained height data. Calculating a slope, checking whether the top surface of the body is on the same plane by using the calculated slope, and as a result of the inspection, when the top surface of the body of the device is located on the same plane, The method may further include determining that it is a failure when not determined on the same plane.

In an embodiment, the checking whether the terminals of the device are located on the same plane by using the obtained height data may include at least two first terminals formed on the first side of the body and the body. Checking whether a slope between at least two or more second terminals formed on a second side of the portion exceeds a preset two-sided slope requirement; and maximum and minimum heights of the first terminals and maximum of the second terminals. The method may further include at least one of checking whether a difference between the height and the minimum height exceeds a preset side height difference allowance.

In one embodiment, the height data of the terminals are obtained from the absolute height data defined from one surface of the substrate on which the device is formed, or is defined relative to the body or relative to the height change of the terminals Can be obtained with relative height data.

In an embodiment, the method for inspecting a failure of the device may include extracting reference height data of the device prior to the step of checking whether the terminals of the device are located on the same plane using the obtained height data. Comparing threshold values obtained by adding the correction height corresponding to the soldering height to the reference height data and the obtained height data when the obtained height data exceeds the threshold value. The method may further include determining that the device is defective. In this case, the reference height data may be obtained from CAD information that records a shape of the device, or may be obtained from learning information obtained by a learning mode.

According to another exemplary embodiment of the present invention, a failure inspection method of a device is inspected for defects of the device using image data obtained by irradiating light generated in a plurality of directions to a device including a body. The defect inspection method of the device may include setting an area corresponding to a body of the device as a region of interest, acquiring height data of at least two points of the region of interest, and using the acquired height data. Calculating an inclination of the body, inspecting whether an upper surface of the body is coplanar using the calculated inclination, and as a result of the inspection, an upper surface of the body of the device is coplanar Determination of good when positioned on the image, and determining that it is bad when not located on the same plane.

In one embodiment, the device may include any one of a ball grid array (BGA) type device and a two-terminal type device having one terminal on each side thereof.

In example embodiments, the height data may be obtained from absolute height data defined from one surface of the substrate on which the device is formed, or from relative height data defined relatively according to a change in height of the body. The calculating of the slope of the body using the height data may include forming a height trend line of the body by using the obtained absolute height or relative height data. In this case, the defect inspection method of the device, after forming the height trend line of the body, checking whether the height trend line is formed discontinuously, if the height trend line is formed discontinuously, the height trend line is not And inspecting the continuously formed points, and compensating the discontinuously formed points to be continuously formed by performing phase unwrapping.

In an embodiment, the checking whether the top surface of the body is located on the same plane by using the calculated slope may include checking whether the slope exceeds a predetermined body tilt allowance. Can be.

According to the present invention, by inspecting whether the body or terminals of the device is located on the same plane (coplanarity) by dividing by the type of device mounted on the substrate, it is mounted on the substrate using an inspection method suitable for the type of device It is possible to easily and accurately determine the quality of the connection state according to the type of device.

In addition, when the device to be inspected includes a multi-terminal type device including a plurality of terminals, by measuring the height of the terminals to calculate the slope formed by the terminal, it is easy to check whether the device mounted on the substrate is connected. Can be judged accurately.

In addition, when a device to be inspected for defects includes any one of a BGA type device and a two-terminal type device each having one terminal on each side, the height of the body is measured to calculate the slope of the body to be mounted on the substrate. It is possible to easily and accurately determine whether the connected state of the device is connected.

1 is a flowchart illustrating a defect inspection method of a device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a defect inspection method of a device using the terminal height measuring method of FIG. 1.
3 is a perspective view illustrating a device in which the terminal height measuring method of FIG. 2 is used.
4 is a cross-sectional view taken along line II ′ of FIG. 3.
5 is a plan view of FIG. 3.
6 is a conceptual diagram illustrating a three-dimensional shape measuring apparatus according to an embodiment of the present invention.
FIG. 7 is a flowchart illustrating a method of inspecting a defect of a device using the body height measuring method of FIG. 1.
8 is a plan view illustrating a device in which the body height measuring method of FIG. 7 is used.
FIG. 9 is a cross-sectional view taken along the line II-II 'of FIG. 8.
FIG. 10 is a graph for explaining a process of forming a height trend line of the body illustrated in FIG. 9.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and that one or more other features It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art.

Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a flowchart illustrating a defect inspection method of a device according to an embodiment of the present invention.

Referring to FIG. 1, in the method for inspecting a failure of a device according to an exemplary embodiment of the present disclosure, the connection state of the device may be determined by measuring the height of terminals of the device or the height of the device body.

First, the device to be inspected is selected, and the type of the device is determined (S100). The device selected for inspection is a multi-terminal type in which a plurality of terminals are formed on both sides of the body, a two-terminal type in which one terminal is formed on both sides of the body, and a terminal is formed in the form of a ball grid on the bottom of the body. grid array) type and so on.

Subsequently, an inspection method is selected according to the type of the device (S200). In this case, when the type of the device is a multi-terminal type in which a plurality of terminals are formed on both sides of the body, the terminal height measuring method is selected as a test method according to the type of the device. In addition, when the device type is a 2-terminal type in which one terminal is formed on each side of the body or a ball grid array (BGA) type in which the terminals are formed in a ball grid on the bottom surface of the body, the inspection according to the type of the device The body height measurement method is selected as the method.

Next, the terminal height measurement method is performed according to the selected inspection method (S300), or the body height measurement method is performed (S400). A specific implementation process of the inspection method will be described in more detail below.

FIG. 2 is a flowchart illustrating a defect inspection method of a device using the terminal height measuring method of FIG. 1. 3 is a perspective view illustrating a device in which the terminal height measuring method of FIG. 2 is used, FIG. 4 is a cross-sectional view taken along line II ′ of FIG. 3, and FIG. 5 is a plan view of FIG. 3.

2 to 5 may include a multi-terminal type device including a plurality of terminals.

2 to 5, in order to perform the terminal height measuring method (S300), an area corresponding to the terminals 24 of the device 20 including a body 22 and a plurality of terminals 24 first. Is set separately from the region corresponding to the body 22 of the device 20 into a separate region of interest (S310). For example, as shown in FIG. 5, the device 20 may include a first region of interest ROIa corresponding to the first side 22a of the body 22 and a second side of the body 22. The second ROIb corresponding to 22b and the third ROIc corresponding to the body 22 may be separately set.

Subsequently, height data of the terminals 24 of the device 20 positioned in the region of interest are measured to obtain height data of the terminals 24 (S320). In one embodiment, the height data of the terminals 24 is a height H1 defined from one surface of the substrate on which the device 20 is formed, for example, the bottom surface of the base substrate 12 as shown in FIG. 4. ) Can be obtained with absolute height data. As another example, the absolute height data may be based on the top surface of the base substrate 12 or the top surface of the solder resist 16 formed on the top surface. Alternatively, the height data of the terminals 24 may be obtained as relative height data defined relatively with respect to the body 22, and the relative data defined relative to the height change of the terminals 24. It may be obtained with height data.

 In one embodiment, the height data of the terminals 24 may be obtained by a three-dimensional shape measuring device. Hereinafter, a three-dimensional shape measuring apparatus according to an embodiment of the present invention will be described in more detail.

6 is a conceptual diagram illustrating a three-dimensional shape measuring apparatus according to an embodiment of the present invention.

Referring to FIG. 6, a three-dimensional shape measuring apparatus used in a method for inspecting a defect of a device according to an exemplary embodiment of the present invention may include a measurement stage unit 100, an image photographing unit 200, and first and second illumination units 300 and 400. ), An image acquisition unit 500, a module control unit 600, and a central control unit 700.

The measurement stage unit 100 may include a stage 110 for supporting the printed circuit board 10 on which the device 20 is mounted, and a stage transfer unit 120 for transferring the stage 110. . In an embodiment, when the printed circuit board 10 is moved to a desired position by the stage 110, the image capturing unit 200 and the first and second lighting units 300 and 400 are moved to a predetermined position. In this case, the measurement position of the printed circuit board 10 may be adjusted.

The image capturing unit 200 is disposed above the stage 110 and receives the light reflected from the device 20 to measure an image of the device 20. That is, the image capturing unit 200 receives the light emitted from the first and second lighting units 300 and 400 and reflected from the device 20 to capture a 3D image of the device 20.

The image capturing unit 200 may include a camera 210, an imaging lens 220, a filter 230, and a lamp 240. The camera 210 receives the light reflected from the device 20 to take an image of the device 20, and as an example, one of a CCD camera and a CMOS camera may be employed.

The imaging lens 220 is disposed under the camera 210 to form light reflected by the device 20 in the camera 210. The filter 230 is disposed below the imaging lens 220 to filter the light reflected from the device 20 to provide the imaging lens 220. For example, the frequency filter, the color filter, and the light intensity are provided. It may be made of any one of the adjustment filter. The lamp 240 may be circularly disposed under the filter 230 to provide light to the device 20 to capture a specific image such as a two-dimensional shape of the device 20.

The first lighting unit 300 may be disposed to be inclined with respect to the stage 110 that supports the printed circuit board 10 on the right side of the image photographing unit 200, for example. The first lighting unit 300 may include a first lighting unit 310, a first grating unit 320, a first grating transfer unit 330, and a first condensing lens 340. The first lighting unit 310 is composed of an illumination source and at least one lens to generate light, the first grating unit 320 is disposed below the first lighting unit 310 to the first illumination The light generated in the unit 310 is changed into the first lattice pattern light having the lattice pattern.

The first lattice transfer unit 330 is connected to the first lattice unit 320 to transfer the first lattice unit 320, for example, one of a piezolectirc (PZT) transfer unit or a fine linear transfer unit. It can be adopted. The first condenser lens 340 is disposed under the first grating unit 320 to condense the first grating pattern light emitted from the first grating unit 320 to the device 20.

The second lighting unit 400 may be inclined with respect to the stage 110 supporting the printed circuit board 10 on the left side of the image capturing unit 200, for example. The second lighting unit 400 may include a second lighting unit 410, a second grating unit 420, a second grating transfer unit 430, and a second condensing lens 440. Since the second lighting unit 400 is substantially the same as the first lighting unit 300 described above, detailed descriptions thereof will be omitted.

The first lighting unit 300 when the first grating transfer unit 330 irradiates the N first grating pattern light to the element 20 while moving the first grating unit 320 sequentially N times The image capturing unit 200 may photograph the N first pattern images by sequentially receiving the N first grating pattern lights reflected from the device 20.

In addition, the second lighting unit 400 irradiates N second grating pattern lights to the device 20 while the second grating transfer unit 430 moves the second grating unit 420 sequentially N times. In this case, the image capturing unit 200 may photograph the N second pattern images by sequentially receiving the N second grating pattern lights reflected from the device 20. Here, N is a natural number, for example, may be 4.

Meanwhile, in the present exemplary embodiment, only the first and second lighting units 300 and 400 are described as an illumination device for generating the first and second grid pattern lights. Alternatively, the number of the lighting units may be three or more. That is, the grid pattern light irradiated to the device 20 is irradiated from various directions so that various kinds of pattern images may be photographed.

For example, when three lighting units are arranged in an equilateral triangle shape around the image capturing unit 200, three grid pattern lights may be applied to the device 20 in different directions, and four lighting units may be applied. When arranged in a square shape around the image capturing unit 200, four grid pattern lights may be applied to the device 20 in different directions.

The image acquisition unit 500 is electrically connected to the camera 210 of the image capturing unit 220 to acquire and store the pattern images from the camera 210. For example, the image acquisition unit 500 includes an image system that receives and stores the N first pattern images and the N second pattern images photographed by the camera 210.

The module controller 600 is electrically connected to and controlled by the measurement stage unit 100, the image capturing unit 200, the first lighting unit 300, and the second lighting unit 400. The module controller 600 includes, for example, a lighting controller, a grid controller, and a stage controller.

The lighting controller generates light by controlling the first and second lighting units 310 and 410, respectively, and the grid controller controls the first and second grid transfer units 330 and 430, respectively. The second grid units 320 and 420 are moved. The stage controller may control the stage transfer unit 120 to move the stage 110 up, down, left, and right.

The central control unit 700 is electrically connected to the image acquisition unit 500 and the module control unit 600 to control each. Specifically, the central control unit 700 receives the N first pattern images and the N second pattern images from the image system of the image acquisition unit 500, processes the same, and processes the N first pattern images. Calculate the three-dimensional shape. In this case, the three-dimensional shape may include height information according to the position of the device 20 mounted on the printed circuit board 10. The central control unit 700 may control the lighting controller, the grid controller, and the stage controller of the module controller 600, respectively. As such, the central control unit may include an image processing board, a control board, and an interface board.

Referring back to FIGS. 2 to 5, next, the coplanarity is checked whether the terminals 24 of the device 20 are located on the same plane using the obtained height data (S330). Subsequently, as a result of the inspection, when the terminals 24 of the device 20 are located on the same plane, it is determined as good, and when not located on the same plane, it is determined as bad (S340).

  Whether the terminals 24 of the device 20 are located on the same plane is determined by the first terminals 24a positioned in the first ROI and the second terminal located in the second ROIb. It may be determined whether at least one of the 24b is located on the same plane. In addition or separately, the relationship between the first terminals 24a and the second terminals 24b may be used to determine whether they are located on the same plane.

In one embodiment, at least two or more first terminals formed on the first side 22a of the body 22 to check whether the terminals 24 of the element 20 are coplanar. It is possible to check whether the slopes formed by 24a) exceed the preset ipsilateral slope allowance. If any one or more of the first terminals 24a formed on the first side 22a of the device 20 are defective, the defective first terminal 24a protrudes above the good first terminal 24a. It is. Therefore, in the case of forming a straight line in parallel with the arrangement direction of the first terminals 24a, the inclination of the straight line is theoretically 0 so that the first terminals 24a are horizontally positioned on the same plane. However, when the slope has a small value, it may be determined that the first terminals 24a are positioned horizontally on the same plane. Therefore, after setting a predetermined ipsilateral slope allowance in advance, When not exceeding, it may be determined that the first terminals 24a are located on the same plane.

In another embodiment, the difference between the maximum height and the minimum height of the first terminals 24a allows a preset ipsilateral height difference to check whether the terminals 24 of the element 20 are coplanar. You can check whether the condition is exceeded. If any one or more of the first terminals 24a formed on the first side 22a of the device 20 are defective, the defective first terminal 24a protrudes above the good first terminal 24a. It is. Therefore, the difference between the maximum height and the minimum height of the first terminals 24a should be theoretically zero so that the first terminals 24a are positioned horizontally on the same plane. However, when the difference between the maximum height and the minimum height has a small value, it may be determined that the first terminals 24a are positioned horizontally on the same plane. After setting, if the allowable condition is not exceeded, it may be determined that the first terminals 24a are located on the same plane.

In another embodiment, to determine whether the terminals 24 of the device 20 are coplanar, a difference between the respective heights and the average heights of the first terminals 24a allows a preset average height. You can check whether the condition is exceeded. If any one or more of the first terminals 24a formed on the first side 22a of the device 20 are defective, the defective first terminal 24a protrudes above the good first terminal 24a. It is. Therefore, the difference between each height and the average height of the first terminals 24a should be in theory zero so that the first terminals 24a are positioned horizontally on the same plane. However, when the difference between each height and the average height has a small value, it may be determined that the first terminals 24a are positioned horizontally on the same plane, so that a predetermined average height allowance condition is set in advance. After that, if the allowable condition is not exceeded, it may be determined that the first terminals 24a are located on the same plane.

The determination methods described above may use only one method or a combination of several methods, and check the second terminals 24b in the same manner as the inspection method for the first terminals 24a. Can be performed. Inspection of the first terminals 24a and inspection of the second terminals 24b may optionally or both be used to determine whether the terminals 24 of the device 20 are coplanar. can do.

On the other hand, whether the terminals 24 of the device 20 are located on the same plane, as described above, using the relationship between the first terminal 24a and the second terminal 24b May be determined.

In one embodiment, the first terminals 24a formed on the first side 22a of the body 22 and to check whether the terminals 24 of the device 20 are coplanar. It may be checked whether the slope between the second terminals 24b formed on the second side 22b of the body 22 exceeds a preset two-sided slope allowance. If any one or more of the terminals 24 formed in the element 20 are defective, the defective terminal 24 protrudes above the good terminal 24. Thus, in the case of forming a straight line perpendicular to the arrangement direction of the terminals 24, i.e., across the first side 22a and the second side 22b of the body 22, in theory the slope of the straight line It should be zero so that the terminals 24 are horizontally located on the same plane. However, if the slope has a small value, the terminals 24 may be determined to be horizontally positioned on the same plane, and thus, after setting a predetermined two-sided inclination allowance in advance, it does not exceed the allowance. If not, it can be determined that the terminals 24 are on the same plane.

In another embodiment, the maximum height and minimum height of the first terminals 24a and the second terminals 24b of the second terminal 24b may be used to check whether the terminals 24 of the device 20 are located on the same plane. It can be checked whether the difference between the maximum height and the minimum height exceeds the preset two-sided height tolerance. If any one or more of the terminals 24 formed in the element 20 are defective, the defective terminal 24 protrudes above the good terminal 24. Therefore, the difference between the maximum height and the minimum height of the terminals 24 should be theoretically zero so that the terminals 24 are horizontally located on the same plane. However, when the difference between the maximum height and the minimum height has a small value, it may be determined that the terminals 24 are positioned horizontally on the same plane, and thus a predetermined side height allowance condition is set in advance. If it does not exceed the allowable condition, it can be determined that the first terminals 24a are located on the same plane.

The above-described determination methods may be any one method or a combination of several methods. The determination method for the first terminals 24a and the inspection method for the second terminals 24b may be optional. Or both may be used to check whether the terminals 24 of the device 20 are coplanar.

Meanwhile, all of the above-described allowable conditions may be set by using a value arbitrarily set by the user or through a learning mode. Detailed description of the learning mode will be described later.

In addition, the defect inspection method of the device, setting the third ROIc corresponding to the body 22 of the device 20, obtains the height data of at least two points to calculate the slope, By checking whether the upper surface of the body is located on the same plane using the calculated slope, it may be determined whether the device is defective. The method is substantially the same as the body height measurement method described later. On the other hand, the method can be performed independently or in combination with the above-described various inspection methods.

On the other hand, the defect inspection method of the device, before checking whether the terminal of the device is located on the same plane by using the obtained height data (S330), by drawing the reference height data of the device, Comparing the acquired height data with thresholds obtained by adding a correction value corresponding to a soldering height to the extracted reference height data, and as a result, when the obtained height data exceeds the threshold, the device is removed. It may be judged as bad. Since the height data obtained by using a three-dimensional shape measuring device or the like is larger than the reference height data by the predetermined soldering 30, the correction value corresponding to the height of the soldering 30 is added to the reference height data. This can be compensated.

The reference height data may be obtained from CAD information that records a shape of the device. In this case, the CAD information includes the design information of the device 20.

Alternatively, the reference height data may be obtained from learning information obtained by a learning mode. The learning mode is a process of obtaining basic data about a device mounted on a bare substrate by learning. For example, as shown in FIG. 4, the bare substrate 10a may include a base substrate 12 and a pad 14 and a solder resist 16 formed on the base substrate 12. In the learning mode, for example, the basic data about the device 20 may be obtained by fixing the device 20 to the bare substrate 10a using a double-sided tape or the like, and measuring the device 20. For example, the learning information obtained by the learning mode may include positions, areas, height values, etc. of the body 22 and the terminals 24 of the device 20 mounted on the bare substrate 10a. have.

As described above, when the device to be inspected includes a multi-terminal type device including a plurality of terminals, the height of the terminals is measured to calculate the inclination of the terminals to determine whether the device is mounted on the substrate. It can be judged easily and accurately.

FIG. 7 is a flowchart illustrating a method of inspecting a defect of a device using the body height measuring method of FIG. 1. 8 is a plan view illustrating a device in which the body height measuring method of FIG. 7 is used, and FIG. 9 is a cross-sectional view taken along the line II-II ′ of FIG. 8.

The target device of the failure inspection method described in FIGS. 7 to 9 may include any one of a ball grid array (BGA) type device and a two-terminal type device having one terminal on each side thereof.

7 to 9, in order to perform the body height measuring method (S400), an area corresponding to the body 22 of the device 20 including the body 22 and the terminals 24 is first interested. The area ROIc is set (S410).

Subsequently, height data of at least two or more points of the ROIc are acquired (S420). For example, height data may be obtained for two measurement points MP1 and MP2 of the ROIc. In one embodiment, the height data of the terminals 24 is a height H2a defined from one surface of the substrate on which the device 20 is formed, for example, the bottom surface of the base substrate 12 as shown in FIG. 9. , H2b) can be obtained. As another example, the absolute height data may be based on the top surface of the base substrate 12 or the top surface of the solder resist 16 formed on the top surface. Alternatively, the height data of the terminals 24 may be obtained with relative height data defined relatively according to the height change of the body 22.

Next, the slope of the body is calculated using the obtained height data (S430). For example, the height trend line of the body 22 may be formed using the obtained absolute height or relative height data.

FIG. 10 is a graph for explaining a process of forming a height trend line of the body illustrated in FIG. 9.

Referring to FIG. 10, after the heights of two measurement points MP1 and MP2 of the ROIc are illustrated, the height trend line L1 is formed by connecting the measurement points MP1 and MP2. can do. As such, by forming a height trend line L1, a slope between the two measurement points MP1 and MP2 can be calculated, and the slope is the body 22 formed between the measurement points MP1 and MP2. Can be seen as

Although the above-described example is an example of two measurement points MP1 and MP2, the measurement points MP1 and MP2 are respectively shown in plan view as shown in FIG. 8. The average value of the straight lines L2 and L3 perpendicular to the straight line between the measurement points MP1 and MP2 while passing through MP2 may be used. In addition, the height trend line L1 may be formed by selecting more measurement points between the measurement points MP1 and MP2.

In this case, the measurable height of the three-dimensional shape measuring apparatus may be limited to a certain range. In this case, the height trend line L1 may be discontinuously formed at a point beyond the measuring range. Therefore, when the height trend line is formed discontinuously by checking whether the height trend line L1 is formed discontinuously, inspecting a point at which the height trend line is formed discontinuously, and then phase unwrapping the discretely formed point. Phase unwrapping can be done to compensate for the continuous formation.

Referring back to FIGS. 7 to 9, the coplanarity is inspected using the calculated slope (S440). At this time, by checking whether the inclination exceeds a predetermined body inclination allowance condition, it is possible to determine whether the upper surface of the body 22 is located on the same plane. The allowable condition may be set using a value arbitrarily set by the user or through a learning mode. Since the description of the learning mode is substantially the same as that described with reference to FIGS. 2 to 6, detailed descriptions thereof will be omitted.

As a result of the inspection, when the upper surface of the body 22 of the device 20 is located on the same plane, it is determined to be good, and when not located on the same plane, it is determined to be defective (S450). That is, when the upper surface of the body 22 is not located on the same plane, it may be determined that at least some of the terminals 24 formed on the body 22 protrude, so that the device 20 is defective. You can judge.

As described above, when the device to be inspected for defect includes any one of a BGA type device and a two-terminal type device having one terminal on each side, the height of the body is measured to calculate the inclination of the body on the substrate. It is possible to easily and accurately judge the quality of the connection state of the mounted device.

While the present invention has been described in connection with what is presently considered to be practical and exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the above description and the drawings below should be construed as illustrating the present invention, not limiting the technical spirit of the present invention.

10: printed circuit board 20: device
22: body 24: terminal
100: measurement stage unit 200: video photographing unit
300: first lighting unit 400: second lighting unit
500: image acquisition unit 600: module control unit
700: central control unit H1, H2a, H2b: height of terminals

Claims (13)

delete delete delete delete delete delete delete delete In the defect inspection method of the device for inspecting the defect of the device by using the image data obtained by irradiating light generated in a plurality of directions to the device including a body (body),
Setting a region corresponding to a body of the device as a region of interest;
Obtaining height data of at least two points of the ROI;
Calculating a slope of the body using the obtained height data;
Inspecting whether the upper surface of the body is located on the same plane using the calculated inclination (coplanarity); And
As a result of the inspection, when the upper surface of the body of the device is located on the same plane is determined to be good, and when not located on the same plane comprising the step of determining as bad,
The height data are obtained from absolute height data defined from one surface of the substrate on which the device is formed, or from relative height data defined relatively according to the height change of the body.
The step of calculating the slope of the body using the obtained height data includes forming a height trend line of the body using the obtained absolute height or relative height data,
After forming the height trend line of the body,
Checking whether the height trend line is formed discontinuously;
If the height trend line is formed discontinuously, inspecting a point where the height trend line is formed discontinuously;
Compensating for the discontinuously formed points to be continuously formed by performing phase unwrapping. 10. The method of claim 9, wherein the device comprises one of a ball grid array (BGA) type device and a two-terminal type device having one terminal on each side thereof. delete delete 10. The method of claim 9,
The step of checking whether the upper surface of the body is located on the same plane by using the calculated slope,
And checking whether the slope exceeds a predetermined body tilt allowance.

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