Quality assurance system and internal inspection device

Abstract

A quality assurance system comprising an external viewing inspection device (230) that checks the connection status between an electrode on a printed circuit board (601) and a component mounted on the printed circuit board (601) by soldering using a visible light-generated image, and an internal viewing device (240) that checks the connection status between the electrode on the printed circuit board (601) and the component mounted on the printed circuit board (601) by soldering in a manner other than by a visible light-generated image, characterized in that the external viewing inspection device (230) generates connection information, which is information on the position of a connection that the electronic component has on the printed circuit board (601), wherein the connection information includes information on the height of the connection in relation to the electrode on the printed circuit board (601), wherein the connection height is an actual measured value.and the internal test device (240) uses the connection information to define an area for performing a test.

Description

1. Technical area

[0001] The present invention relates to a system for checking the condition of a component mounted on a printed circuit board. 2. State of the art

[0002] Surface mounting (SMT) is a method for mounting components onto printed circuit boards (PCBs). In SMT, solder paste is applied to the PCB, and the components to be mounted are placed on it. The components are then fused by applying heat and melting the solder. Because this method allows for the production of circuit boards with a high degree of integration, surface mounting is frequently used in automated component placement systems.

[0003] In the case of automated component placement on the circuit board, an inspection is necessary after the solder has cooled to determine whether the components are correctly mounted on the board (hereinafter referred to as "reflow follow-up inspection"). To ensure product quality, it is particularly important to precisely assess whether the connection points between the component leads and the electrodes on the circuit board (solder pads) have been correctly soldered.

[0004] To perform reflow follow-up testing, it is necessary to precisely identify the position of each component on the circuit board. A related technique, disclosed in Japanese patent publication JP 2011-91181A, involves a component placement system. In this system, a placement machine transmits information about the component's dimensions to a test fixture for verifying the component's connection status. Based on this information, the test fixture identifies the location to be inspected. According to this component placement system, the test fixture can correctly identify the component size even if the size of individual components varies due to individual differences.

[0005] In Japanese patent publication JP 2004 - 151 057 A, a method is described in which a component that is a test object is identified, an optimal test library is selected, and the test is performed.

[0006] There are two methods for performing reflow follow-up inspection: AOI and AXI. AOI (automated optical inspection) involves using a camera to photograph a test object and analyzing the images to determine the bond strength between the component and the circuit board. AXI (automated X-ray inspection) involves irradiating the test object with X-rays, and the bond strength between the component and the circuit board is determined based on the resulting X-ray image. AOI detects defects based on the external appearance, while AXI detects defects that are not visible externally.

[0007] In reflow post-inspection, the contact condition between a terminal and the solder is checked. Therefore, it is necessary to distinguish between the area where the terminal is located (hereinafter referred to as the "terminal area") and the area where the solder is located (hereinafter referred to as the "solder area"). If these two cannot be distinguished, it is impossible to accurately assess the solder contact angle or the solder application thickness.

[0008] For example, in a test device using the AOI method, a camera captures the component, and the resulting image allows the connection area to be identified. In contrast, a test device using the AXI method exploits the difference in X-ray transmittance between conductive and non-conductive materials, enabling the detection of areas containing metal. Even though both involve metal, the X-ray transmittance varies depending on the material, allowing for the differentiation between solder and connection.

[0009] However, since the AXI method involves taking a transparent X-ray image and generating and analyzing three-dimensional data, image analysis takes longer than analyzing images created using visible light. If the inspection time needs to be reduced, the resolution must be lowered, which decreases the accuracy in distinguishing between a connection and a solder joint.

[0010] However, it is also conceivable, according to the techniques from Japanese patent publications JP 2011-91181A and JP 2004-151057A, to detect the area where the connection is located in advance during assembly and to use this information for subsequent reflow inspection. However, since the assembled component sinks during the reflow process as the solder melts, the component's height position changes. Therefore, even if the connection area is detected before the reflow process, the corresponding information cannot be used for subsequent reflow inspection. Furthermore, JP 2007-192598A discloses an optical imaging unit, an X-ray imaging unit, and an inspection unit. The optical imaging unit captures an optical image of an object to be inspected.The X-ray imaging unit is used to generate an image of an X-ray image displayed on an optical conversion unit by irradiating an object to be inspected with X-rays. The inspection unit is used to define an inspection target area by using a projected optical image and to inspect the attachment status of the component of the object to be inspected by examining the X-ray image within the defined inspection target area. The inspection unit defines an inspection target area of ​​the target surface by using an optical image of the projected inspection target surface. The inspection unit defines a component area occupied by a component located on the back side of the target surface by using an optical image of the back side of the projected inspection target surface.The inspection unit inspects the X-ray image in the inspection target area, which is defined using the defined component area.

[0011] JP 2005 – 286 309 A discloses how to obtain information regarding the position and size of an electrode and its corner coordinates from an image of an unpopulated circuit board. This information is then used to verify the relationship between a solder fillet and the electrode, and to perform a fillet inspection.

[0012] The present invention was made taking into account the aforementioned problems, and its object is to provide a technique in which the speed for performing an internal inspection is increased in a surface assembly line. overview

[0013] To solve the aforementioned problem, a quality assurance system according to the present invention is configured such that, after completion of the reflow process, when performing an AOI test, the position of a connection that an electronic component has is detected, and the information on the relevant connection position is used when performing an AXI test.

[0014] Specifically, the quality assurance system according to the present invention is a quality assurance system comprising an external viewing inspection device that checks the connection state between an electrode on a printed circuit board and a component mounted on the printed circuit board by means of solder using an image generated by visible light, and an internal viewing device that checks the connection state between the electrode on the printed circuit board and the component mounted on the printed circuit board by means of solder in a manner other than by means of an image generated by visible light, wherein the external viewing inspection device generates connection information, which is information on the position of a connection that the electronic component has on the printed circuit board, wherein the connection information includes information on the height of the connection in relation to the electrode on the printed circuit board (601).where the connection height is an actual measured value, and the internal testing device uses the connection information to determine an area in which the test is performed.

[0015] The use of non-visible light, such as X-rays, to distinguish the connection area from the solder area presents the problem that the processing takes time. Therefore, the quality assurance system of the present invention is configured such that, when performing a reflow follow-up inspection using an image generated by visible light, connection information is generated, which is information about the position of a connection, and the internal inspection device uses this connection information to determine a test object area when performing the inspection.Since the connection information is obtained from an image generated by visible light, the amount of information is small compared to three-dimensional data obtained, for example, by X-ray images; however, the internal inspection device can exclude such areas, which are clearly useless, from the area for carrying out the inspection.

[0016] Since, for example, the height or length of components mounted on the circuit board varies depending on the mounting state or individual component differences, the internal inspection device must scan the largest possible area if no connection information is available. In contrast, the external inspection device uses an image generated by visible light to detect the area where a connection is clearly present and generates the connection information. Therefore, because the internal inspection device can identify the area where a connection is clearly present, the area under inspection can be narrowed down. This avoids unnecessary scanning and reduces the time required for internal inspection.

[0017] The connection information is characterized in that it includes information on the height of the connection relative to the electrode on the printed circuit board. The internal test device can be characterized in that it uses the connection information to set an upper height limit for performing the test and uses the area as the test object that is lower than this upper height limit.

[0018] Areas requiring internal inspection are those whose upper limit is the height of a terminal on a component and whose lower limit is the height of the electrode on the circuit board. This means that by informing the internal inspection device of the height of the terminal to be inspected, the external inspection device can define the inspection area.

[0019] The connection information may also be characterized by including information indicating the relative position of a connection to a reference position set on the electrode, the width of the connection, and the offset amount in relation to the electrode.

[0020] The connection information can include not only information displaying the connection height (Z-direction) but also information displaying its position and size in a plane (XY-plane). Since this configuration allows internal testing to begin in a state with a specific connection position, extracting the test object area in the XY-plane is unnecessary during the internal test, thus accelerating the test. Because the internal test device performs the test with reference to the electrode on the circuit board, the connection area is preferably displayed using a position referenced to the electrode.

[0021] The internal testing device can also be characterized by the fact that it performs the testing of the connection condition using an X-ray layer image.

[0022] The present invention is particularly advantageous for an internal inspection system using X-rays. The layered image can be obtained directly by creating layered images, and it can also be obtained from several transparent images by changing the angle, whereby a three-dimensional shape is generated by combining the obtained transparent images and the layers are extracted from the generated shape.

[0023] The internal testing device can also be characterized in that it obtains information on the thickness of a connection that an electronic component has and furthermore determines the area for carrying out the test based on the information on the thickness of a connection.

[0024] For example, to determine the contact area between the terminal and the electrode, several layer images must be acquired and the lower end of the terminal detected, after which the area must be calculated. However, if the terminal thickness can be determined, this reduces the number of layer images required, as the height for obtaining the layer images can be determined, thus speeding up the inspection. Therefore, by obtaining information about the terminal thickness from the outside, the position of the lower terminal end can be determined, further reducing the processing effort for internal inspection.

[0025] The present invention can specifically be a quality assurance system comprising at least one of the means described above. The present invention can also specifically be a method for controlling the quality assurance system, a program for operating the quality assurance system, and a storage medium on which the program is stored. The present invention can further specifically be an internal testing device that constitutes the quality assurance system.

[0026] Provided that no technical contradictions are created, the aforementioned processing operations and means can be freely combined.

[0027] According to the present invention, the speed of internal inspection can be increased in a surface assembly line. To solve this problem, an internal inspection device is also proposed, which is configured to communicate with an external inspection device. The external inspection device checks the connection status between an electrode on a printed circuit board and a component soldered onto the printed circuit board by means of a visible light-generated image. The external inspection device also checks the connection status between the electrode on the printed circuit board and the component soldered onto the printed circuit board in a manner other than by means of a visible light-generated image. wherein the internal inspection device obtains connection information from the external inspection device, which is information on the position of a connection that the electronic component has on the printed circuit board, wherein the connection information includes information on the height of the connection in relation to the electrode on the printed circuit board, which connection height is an actual measured value, and the internal inspection device uses the connection information to determine an area for performing a test. Brief description of the characters Fig. 1. A flowchart explaining the manufacturing and testing of a circuit board using the reflow process; Fig. 2 a view that explains an overview of an examination according to an embodiment; Fig. 3 a view that explains the assessment of the solder joint condition; Fig. 4A and B show an explanatory view of the area for carrying out an X-ray examination; Fig. 5 a data structure of test object information that is sent to the individual test devices; Fig. 6 an explanatory view of a method for determining an area in which a component is located; Fig. 7 an explanatory view of a procedure for determining an area in which a connection exists; Fig. 8 an example of connection information in a first embodiment; Fig. 9 an operating flow diagram of the external view inspection device; Fig. 10 an operating flow diagram of the X-ray testing device; Fig. 11 an example of connection information according to a second embodiment; Fig. Figures 12A and B show an explanatory view of a method for determining a connection area in the second embodiment; Fig. 13 an explanatory view of the connection thickness in a third embodiment; and Fig. 14 an example of connection thickness information in the third embodiment. Detailed description of system configuration

[0028] Fig. Figure 1 is a schematic view of a configuration example of a production plant and a quality assurance system in a surface mount technology (SMT) line for printed circuit boards. Surface mount technology is a technique for soldering electrical components to the surface of printed circuit boards, and a surface mount line is primarily configured with the three steps of solder paste printing, component placement, and reflow (melting the solder).

[0029] As in Fig. As shown in Figure 1, the surface mounting line comprises, in descending order of importance, a solder printing device 110, a pick-and-place machine 120, and a reflow oven 130. The solder printing device 110 is a device that applies paste-like solder to the electrode section of a printed circuit board (referred to as the "solder pad") using screen printing. The pick-and-place machine 120 is a device that picks up the electrical component to be mounted on the circuit board and places the component onto the solder paste at the designated location; it is also referred to as a chip pick-and-place machine. The reflow oven 130 is a heating device that heats and melts the solder paste and then cools it to solder the electrical component to the circuit board. The aforementioned production equipment 110 to 130 is connected via a network (LAN) to a production equipment management device 140.The production plant management device 140 is a system for managing or overarching control of production plants 110 to 130. It includes functions for storing, managing, or outputting execution programs that govern the operation of the production plants (including operating sequences, production conditions, setting parameters, etc.) and log data for each production plant. The production plant management device 140 also includes a function for updating an execution program set in a particular production plant when an update command for the execution program is received from an operator or another device.

[0030] The surface finish assembly line also incorporates a quality assurance system at the output of each step – solder paste printing, component assembly, and reflow – which checks the condition of the circuit board and automatically detects whether a defect or the possibility of a defect exists. In addition to automatically distinguishing between flawless and defective products, the quality assurance system also has a function that provides feedback to the operation of the individual production line based on a test result or its analysis (for example, to update an execution program).

[0031] How Fig. As shown in Figure 1, the quality assurance system of the embodiment is configured with four different testing devices, namely a solder pressure testing device 210, a component testing device 220, an external view testing device 230 and an X-ray testing device 240, as well as with a test management device 250, an analysis device 260 and a workstation computer 270.

[0032] The solder pressure tester 210 is a device that checks the solder paste pressure condition on the circuit board dispensed by the solder pressure tester 110. The solder pressure tester 210 measures the solder paste printed on the circuit board two- or three-dimensionally and, based on the measurement results for various test points, determines whether a normal value (within a permissible range) is present. Test points can include, for example, the volume, area, height, positional deviation, or shape of the solder.

[0033] For two-dimensional measurement of the solder paste, an image sensor (camera) can be used, and for three-dimensional measurement, a laser offset calculation, a phase shift method, a space coding method, a light section method or the like can be used.

[0034] The component testing device 220 is a device that performs an inspection of the arrangement of electrical components on the circuit board dispensed by the pick-and-place machine 120. The component testing device 220 measures the components (or a part of the component body, or the electrode (conductor)) arranged on the solder paste in two or three dimensions and determines, based on the measurement results for various test points, whether a normal value (within a permissible range) is present. Examples of test points include a component's positional deviation, an angular deviation (rotation), a missing component (a component not being arranged), a component mix-up (incorrect component arrangement), a polarity reversal (incorrect polarity of the electrodes on the component side and the circuit board side), a front-to-back orientation (component arranged with the front facing down), component height, and the like.

[0035] As with solder pressure testing, an image sensor (camera) can be used for the two-dimensional measurement of electronic components, and for the three-dimensional measurement, a laser offset calculation, a phase shift method, a space coding method, a light section method or the like can be used.

[0036] The external inspection device 230 is a device that performs an inspection of the soldering condition on the circuit board ejected from the reflow oven 130. The external inspection device 230 measures the soldered components two- or three-dimensionally after reflow and determines, based on the measurement results for various test points, whether a normal value (within a permissible range) is present. In addition to the component inspection points, the test points can also include an assessment of the solder joint shape or similar characteristics.When measuring the plumb line shape, methods such as laser offset calculation, phase shift method, spatial coding method, light section method or similar can be used, as described above, or a so-called color highlighting method (illumination in RGB colors is shone onto the plumb line surface with different angles of incidence and the reflected light of the individual colors is recorded with a ceiling camera, whereby the three-dimensional shape of the plumb line is output in the form of two-dimensional color phase information).

[0037] The X-ray inspection device 240 is an internal inspection device that uses an X-ray image to check the condition of the soldering on the circuit board. In the case of packaged components such as BGAs (ball grid arrays) or CSPs (chip-size packages), or multilayer circuit boards, the solder joint section is hidden beneath the components or the circuit board itself. Therefore, the external inspection device 230 (i.e., using images of the external appearance) cannot be used to check the soldering condition. The X-ray inspection device 240 overcomes these limitations of external inspection. It allows for inspection of areas that cannot be checked based on external appearance, such as the underside of a connector or the back solder joint, thus enabling a more comprehensive quality check after reflow.Examples of inspection points for the X-ray inspection device 240 include the positional deviation of a component, the solder height, the solder volume, the solder pore diameter, the length of the rear solder fillet, or the quality of the solder joint. Radiographic images or CT (computed tomography) images are preferably used as X-ray images.

[0038] The aforementioned test devices 210 to 240 are connected via a network (LAN) to a test management device 250. The test management device 250 is a system for managing or controlling the test devices 210 to 240, and it has the functions for storing, managing, or outputting test programs that determine the operation of the test devices 210 to 240 (including test sequence, test conditions, setting parameters, etc.) and test results or log data of the individual test devices 210 to 240.

[0039] The analysis device 260 is a system that has a function to analyze the test results (test results of the individual steps) of the individual test devices 210 to 240 compiled by the test management device 250 and to perform a defect prediction or a defect cause estimation or the like, and a function to perform feedback to the individual production plants 110 to 130 (update of the execution program, etc.) if required.

[0040] The workstation computer 270 is a system that has a function for displaying the status of the production equipment 110 to 130, the test results of the individual test devices 210 to 240 and the analysis results of the analysis device 260 and the like, a function for changing (editing) execution programs or test programs of the production equipment management device 140 or the test management device 250 and a function for checking the operating status of the surface assembly line as a whole.

[0041] The production plant management device 140, the test management device 250, and the analysis device 260 can each be configured in an ordinary computer system equipped with a CPU (central processing unit), a main memory device (memory), an auxiliary storage device (hard disk or the like), an input device (keyboard, mouse, control unit, touch panel, or the like), and a display device, and the like. Devices 140, 250, and 260 can be separate devices, or devices 140, 250, and 260 can perform all of the aforementioned functions in a single computer system. It is possible for a computer equipped with any of the production plants 110 to 130 or test devices 210 to 240 to perform all of the functions of devices 140, 250, and 260, or some of them. Fig. 1. The production plant and the quality assurance system are a separate network, but as long as they can exchange data with each other, any type of network configuration can be used. First embodiment

[0042] The following describes an embodiment of a quality assurance system on the aforementioned surface assembly line. The quality assurance system of the first embodiment is configured to include an external view inspection device 230, an X-ray inspection device 240, and an inspection management device 250. Fig. Figure 2 shows a flowchart illustrating the sending and receiving of data by the individual devices.

[0043] As already mentioned, the external inspection device 230 and the X-ray inspection device 240 are devices that use visible light beams or X-rays to check whether a connection of an electronic component mounted on a circuit board is properly soldered to a solder pad on the board. That is, they are means of performing an inspection on the finished product. A circuit board found to be defective is classified as defective and, if necessary, subjected to further testing, such as a visual inspection. In the description of the embodiment, the inspection performed by the external inspection device 230 and the X-ray inspection device 240 is referred to as reflow follow-up testing.

[0044] The test fixtures are arranged on a test line and configured to perform a test on a conveyed circuit board. The test management device 250 sends test programs to the individual test fixtures, and the individual test fixtures execute the test on the circuit board based on these programs. When the test is complete, a test result is generated and sent to the test management device 250 (the connection information is described later).

[0045] The content of the inspection carried out by the external view inspection device and the X-ray inspection device shall be described with reference to Fig. Figure 3 describes a sectional view of the part where the solder lug and terminal are connected by solder. Fig. 3 is the black colored area of ​​the connection, while the hatched area is the solder pad.

[0046] As in Fig. As shown in Figure 3, a perfectly formed solder joint creates a wide, sloping surface from the connection to the solder eye, resembling the base of a mountain. Conversely, if there is a solder deficiency, the sloping surface becomes smaller, while with an excessive amount of solder, the solder joint rises all the way to the solder eye. The external inspection device 230 and the X-ray inspection device 240 assess the condition of the joint based on the shape of the solder.

[0047] The assessment of the connection condition can be based, for example, on the length from the end of the solder pad to the end of the connection, the length of the front solder groove, the contact angle of the solder in relation to the solder pad or connection, the thickness of the solder deposit, or similar factors.

[0048] The problem is that the test performed by the X-ray testing device 240 takes time.

[0049] The X-ray inspection device mainly creates several images and generates three-dimensional data based on the obtained X-ray images, and performs an inspection by detecting the connection area and the solder area.

[0050] While X-ray inspection offers the advantage of allowing the examination of parts that are not visible from the outside, it also has the disadvantage, as mentioned previously, of a longer inspection time compared to external visual inspection. If the time required for an X-ray inspection is longer than that required for an external visual inspection, more inspection fixtures than production lines are needed, thus increasing costs. Therefore, the inspection time for X-rays should be minimized as much as possible.

[0051] The following describes the scope of the testing performed by the X-ray testing device. Fig. Figures 4A and B are comparative views of two samples of cross-sectional surfaces through the part where the solder pad and the terminal were joined by soldering. Fig. 4A The X-ray inspection device 240 can perform an inspection on the dotted-bordered area 401. In Fig. In contrast, 4B requires the X-ray inspection device 240 to perform an inspection on the dotted-bordered area 402. The size of the inspection area for the X-ray inspection device 240 therefore changes depending on the assembly state of the component and also due to individual differences between the components.

[0052] The X-ray inspection device 240 also performs the inspection by capturing and combining several transparent images at varying angles to obtain a layered image. Therefore, to correctly assess the solder joint condition, a combined processing of the transparent images must be carried out across the largest possible area. The same applies to the processing for determining the connection between the terminal and the solder after obtaining the layered image. If, as in Fig. 4A, if the height of the connection h is, then it is sufficient if the area up to the height h is the test object, but in the case of the maximum assumed height h' as ​​in Fig. 4B is always the area up to the height h' of the test object, which increases the test duration.

[0053] Therefore, the quality assurance system of the first embodiment checks the position of the connector on the circuit board during the external view inspection and uses the information on the connector position from the X-ray inspection.

[0054] Specifically, during the external view inspection, the external view inspection device 230 records the height of each of the multiple terminals on a component and generates information indicating the height of each terminal (hereinafter referred to as "terminal information"), which it sends along with the inspection result to the inspection management device 250. During the inspection, the X-ray inspection device 240 receives the terminal information from the inspection management device 250 and performs the X-ray inspection using an inspection area that is lower than the maximum height at which a terminal is located. The respective processing steps are described in detail below.

[0055] First, an overview of the tests performed by the individual test devices will be described. In the quality assurance system of this embodiment, the test management device 250, as already mentioned, sends test programs to the individual test devices, and the individual test devices execute the tests based on these test programs. In addition to the test procedure, the test programs also include information about the object to be tested (hereinafter referred to as "test object information").

[0056] Fig. Figure 5 shows an example of a data structure for test object information. The test object information includes information about the components mounted on the circuit board (component information) and information about the test area (test area information). A test area is a unit for performing a test and can be the component body, a connection point to which a component is attached, or a solder pad to which the connection point is attached. In reflow follow-up testing, the test is performed using the solder pad as the object. The test area information contains details about the position and size of the test object, its angle, and the test points or reference, and the individual test fixtures perform the test with reference to this test area information.

[0057] In the example from Fig. For each component, coordinates and angles are defined relative to the circuit board. Additionally, for each test area, coordinates, height, and angle are defined relative to the component. If the test area is the component itself, the coordinates, height, and angle relative to the component are all 0.

[0058] First, the processing using the external inspection device will be described.

[0059] When a printed circuit board (PCB) is conveyed to the external viewing inspection device 230, the device captures the PCB ID of the conveyed PCB. The PCB ID can also be captured, for example, by the production equipment management device 140, and if reading is possible with each receipt of the PCB, it can also be read directly from the PCB. The inspection object information corresponding to the conveyed PCB is then obtained by the inspection management device 250, and the external viewing inspection is performed.

[0060] The external visual inspection involves checking the solder lug, which is defined as the inspection area. With reference to Fig. 6 and Fig. 7 should now define the relationship between the test object information from Fig. 5 and the area in which the test device actually performs a test.

[0061] First, with reference to Fig. 6. A method for determining the component will be described. Fig. Reference numeral 601 denotes the printed circuit board being transported, and reference numeral 602 denotes the area on the printed circuit board where a component is located. The X and Y axes in the figure are axes used to indicate the component's position. The component's position is displayed using an XY coordinate system with the center of the board as the starting point (0, 0). For example, the component's position, designated by reference numeral 602, can be indicated by the coordinates (Xp, Yp) at the component's center point and the angle relative to the board (for example, defined as 0 degrees in the positive direction of the X-axis counterclockwise; in this example, 0 degrees). The parameters correspond to the component information from Fig. 5. Each component specifies the X-coordinate (relative to the circuit board), the Y-coordinate (relative to the circuit board), and the angle (relative to the circuit board). This component information defines the position and orientation of the component on the circuit board.

[0062] Next, with reference to Fig. 7. A method for determining the solder pad, which is the test area, is described.

[0063] The position of the test area is a position relative to the component. Fig. Reference numeral 701 denotes the component body, and reference numeral 702 denotes the solder pad to which the component's terminal is connected. The X and Y axes in the figure are axes for indicating the solder pad's position. The solder pad's position is shown using an XY coordinate system with the component's center point (0, 0) as the starting point. For example, the solder pad designated by reference numeral 702 can be shown with the coordinates (XI, YI) for point 703 at the bottom left of the solder pad, the transverse length of terminal WI, the longitudinal length of terminal HI, and the angle to the component (0 degrees). The parameters correspond to the test area information from Fig. 5. Each of the following values ​​is given: the X-coordinate (relative to the component), the Y-coordinate (relative to the component), the transverse length, the longitudinal length, and the angle (relative to the component). The height is the assumed maximum height of the connection to the solder pad.

[0064] As described above, the component information and the test area information indicate where the area to be tested is located on the circuit board.

[0065] The starting point set on the circuit board is the same for the test devices. Therefore, by displaying the position with reference to the starting point, the area on the circuit board can be uniquely determined.

[0066] The external view inspection device performs an external view inspection for the area defined in this way (soldering eye) (i.e., a check to see if the solder joints were formed correctly, etc.), generates a test result and sends it to the test management device 250.

[0067] As mentioned above, the mounting position of the components varies, so even when the same component is mounted, the height of the connection varies on each circuit board. This increases the time required for X-ray inspection. Therefore, after the external view inspection is complete, the external view inspection device 230 generates connection information indicating the height of the connection to the solder pad.

[0068] Fig. Figure 8 is an example of the connection information generated by the external view inspection device 230. The connection information includes a key for uniquely identifying the connection (board ID, component ID, connection number) and information about the connection height. The connection height is derived from Fig. 8 is not a value based on specifications, but an actual measured value. The height of the connection is calculated for each connection based on the photographs taken during the external inspection. A known analytical method can be used to calculate the height of the connection from images.

[0069] The connection information sent to the test management device 250 is temporarily stored and sent to the X-ray test device 240 together with the test programs for the reflow follow-up test.

[0070] During the inspection of the connection status between the terminal and the solder pad, the X-ray inspection device 240 refers to the obtained terminal information and determines the terminal whose position on the circuit board is highest. It then performs an X-ray inspection on the area lower than this terminal. Specifically, as shown in Fig. Figures 4A and B show that layer images were created from the area from the height of the circuit board to the height of the connector at specific height intervals in the XY direction, and three-dimensional data was generated to check the solder joint condition.

[0071] If no connection information is available for one of the connections on the circuit board, the scan will be performed up to the assumed maximum height to prevent anything from being missed. Processing flowchart

[0072] Fig. 9 is a flowchart of an inspection processing procedure using the external view inspection device 230. The processing from Fig. Test 9 is performed at the same rate as the printed circuit boards forming the test object are conveyed. The test programs are transmitted in advance by the test management device 250.

[0073] First, in step S11, a camera is used to take a picture of the test object, i.e., the circuit board. The picture taken here is for the external visual inspection, but if a separate picture is needed to measure the height of the connector, it can be taken. If multiple pictures are taken, different cameras can be used for each. As long as the external visual inspection can be carried out and the height of the connector measured, it doesn't matter how the pictures are taken.

[0074] Next, in step S12, the solder pad, which is the test object, is extracted with reference to the test object information contained in the test program.

[0075] In step S13, an external view inspection of the individual test objects is carried out using the recording created in step S11, and the test result is generated.

[0076] In step S14, the height of the connections on the relevant circuit board is measured using the image created in step S11. Connection information is then generated and sent to the test management device 250 together with the test result generated in step S13 (step S15).

[0077] Fig. 10 is a flowchart of an inspection process using the X-ray inspection device 240. The processing from Fig. Step 10 is performed at the same rate as the printed circuit boards are conveyed and the X-ray inspection begins. The test programs are transmitted in advance by the test management device 250.

[0078] First, in step S21, the solder pad, which is the test object, is extracted with reference to the test object information contained in the test program.

[0079] Then, in step S22, the test management device 250 obtains the connection information for the solder pad that is the test object. The test object's connections are distinguished by board ID, component ID, and connection number. Since the respective height can be obtained in this step for connections corresponding to multiple solder pads (test objects), the highest connection is determined and temporarily stored. If no connection information can be obtained for the solder pads (test objects), the highest connection is determined based on the information in the test object information.

[0080] In step S23, an X-ray inspection is performed on the solder pads (test objects). As mentioned previously, in an area whose lower limit is the height of the circuit board and whose upper limit is the height stored in step S22, processing is carried out by combining transparent images to generate layer images, and an inspection is performed at specific height intervals. After completion of the inspection, the test result is generated and sent to the test management device 250.

[0081] As described above, in the quality assurance system of the first embodiment, the height of the connector (i.e., the height in the Z-axis direction) is detected and stored during the external inspection after completion of the reflow process, and the X-ray inspection is then performed using this information. Since the X-ray inspection is performed using multiple layer images, if no information on the Z-axis direction is available, a number of layer images corresponding to the assumed maximum height must be acquired. However, in the first embodiment, the acquisition of unnecessary layer images can be avoided, and the number of layer images can be minimized, thus accelerating the inspection. This reduces inspection costs and increases productivity. Second embodiment

[0082] In the first embodiment, the height of the connection (i.e., information about the Z-axis direction) was defined as connection information. In a second embodiment, the connection information is supplemented by information about a region in the XY plane where a connection is located. The configuration of the quality assurance system of the second embodiment is the same as that of the system of the first embodiment; therefore, a detailed description of the second embodiment is omitted, and only the points in which it differs from the first embodiment are described.

[0083] Fig. Figure 11 shows an example of connection information according to the second embodiment. Unlike in the first embodiment, the connection information in the second embodiment is supplemented by three points: connection position, connection width, and offset. The individual points are explained with reference to Fig. 12A and B are described.

[0084] The connection position is a value that indicates the relative position of the connection in relation to the solder pad. In this example, the connection position is defined as the distance from the upper edge of the solder pad, corresponding to the connection, to the center line of the connection.

[0085] The connection width is a value indicating the width of the connection, and the offset is a value indicating the distance from the front of the solder pad (end edge opposite the component) to the front of the connection. By adding this information to the connection data in the second embodiment, the position of an area containing a connection can be displayed in the XY plane. The connection height is defined in the same way as in the first embodiment.

[0086] Next, the differences in the test processing compared to the first embodiment will be discussed ( Fig. 9 and Fig. 10) will be described.

[0087] In the second embodiment, the external view inspection device 230 determines the connection area in the XY plane in step S14 after measuring the height of the connections. A known analysis method can be used to determine the connection area position based on images.

[0088] In step S15, the following are specified for each connection: Fig. The connection information shown in section 11 was generated.

[0089] In step S23, the X-ray inspection is carried out, whereby the X-ray inspection device 240 is used based on the connection information from Fig. 11 determines the test object area. The position of the solder pad, which forms the reference for indicating the connection position, is common for all test object information, which is why the X-ray inspection device 240 can determine the area in which connections are located three-dimensionally.

[0090] Since in the second embodiment, in addition to the height of the connections, the position of the connection area in the XY plane can also be transmitted to the X-ray inspection device, it is no longer necessary to extract the test object area in the XY plane, which further increases the inspection speed during the X-ray inspection. Third embodiment

[0091] The third embodiment is an embodiment in which the inspection management device 250 sends information on the thickness of the connections to the X-ray inspection device 240. The configuration of the quality assurance system of the third embodiment is the same as that of the system of the first embodiment; therefore, its detailed description is omitted, and only the points in which it differs from the first embodiment are described.

[0092] In the third embodiment, the test management device 250 has information showing the thickness of the connections (connection thickness) (hereinafter referred to as "connection thickness information") and sends this information to the X-ray testing device 240 before the start of the test. Fig. 13 is a view to illustrate the connection thickness, and Fig.Figure 14 is an example of connection thickness information. The connection thickness information includes a key for uniquely identifying the connection (board ID, component ID, connection number) and information about the connection thickness for that specific connection. The connection thickness information is based on component specification information and is generated in advance and stored in the inspection management device 250.

[0093] For components such as chip components, where the thickness of the component and the thickness of the connection are essentially the same, the connection thickness can also be replaced by the component thickness.

[0094] When the X-ray inspection device 240 performs the X-ray inspection in step S23, the inspection is carried out using the connection thickness. When measuring the solder area on the underside of the connection, the height is obtained by subtracting the connection thickness from the connection height, and a layer image is created at a position at the midpoint of the solder pad to measure the solder area.

[0095] When using no connection thickness and creating a layer profile, it is necessary to determine where the lower part of the connection is located, but in this way it is sufficient to create a single layer profile to obtain the solder surface.

[0096] The connection thickness can also be used to measure other points. For example, if the solder volume of a joint section is to be determined, the connection thickness can be used to estimate the volume of the connection, and this volume can then be subtracted from the total volume of the joint section. Using this method, the processing required to differentiate between the connection area and the solder area can be eliminated, thus increasing the testing speed.

[0097] In the third embodiment, by sending information about the thickness of the connection to the X-ray testing device and having the X-ray testing device perform the test based on this information about the thickness of the connection, the time required for the X-ray testing can be further reduced.

[0098] In the third embodiment, the lead thickness information is generated in advance and sent to the X-ray inspection device 240 as part of the inspection area information. However, the lead thickness information can also be generated and transmitted using a different method. For example, the placement machine 120, which positions the component on the circuit board, or the component inspection device 220, which checks the component's position, can measure the lead thickness, generate lead thickness information, and send this information to the X-ray inspection device 240 via the inspection management device 250. It is also possible to send it directly without going through the inspection management device 250. Examples of variations

[0099] The description of the embodiments was made only as an example to describe the present invention, and the present invention may be modified or combined as desired, as long as the scope of the invention is not altered.

[0100] For example, in the description of the embodiments, the relative position of the connection was shown based on the distance from the end edge of the solder pad; however, the position of the connection area can also be shown by any other method, as long as it can be determined by the X-ray inspection device. For example, the center point of the solder pad can be set as the starting point, and the indication can be given by relative coordinates originating from this starting point.

[0101] In describing the embodiments, the test management device 250 further summarizes all connection information and sends it at once to the external view test device 230 and the X-ray test device 240, but the connection information can also be transmitted directly between the test devices.

Claims

[1] Quality assurance system comprising an external viewing inspection device (230) that checks the connection state between an electrode on a printed circuit board (601) and a component mounted on the printed circuit board (601) by soldering by means of a visible light-generated image, and an internal inspection device (240) that checks the connection state between the electrode on the printed circuit board (601) and the component mounted on the printed circuit board (601) by means other than by means of a visible light-generated image, characterized by, that the external view inspection device (230) generates connection information, which is information on the position of a connection that the electronic component has on the printed circuit board (601), wherein the connection information includes information on the height of the connection in relation to the electrode on the printed circuit board (601), wherein the connection height is an actual measured value, and the internal inspection device (240) uses the connection information to determine an area for performing an inspection. [2] Quality assurance system according to claim 1, characterized by , that the internal testing device (240) uses the connection information to set a height limit for carrying out the test and uses the area as the test object that is lower than this height limit. [3] Quality assurance system according to claim 1 or 2, characterized by, that the connection information includes information indicating a relative position of the connection to a reference position set on the electrode, a width of the connection, and an offset amount in relation to the electrode. [4] Quality assurance system according to one of claims 1 to 3, characterized by , that the internal testing device (240) performs the testing of the connection condition using an X-ray layer image. [5] Quality assurance system according to any one of claims 1 to 4, characterized by , that the internal testing device (240) obtains information on the thickness of a terminal that the electronic component has and furthermore uses the information on the thickness of the terminal to determine the area for carrying out the test. [6] Internal inspection device (240) which is configured to communicate with an external inspection device (230) which checks the connection state between an electrode on a printed circuit board (601) and a component mounted on the printed circuit board (601) by means of a visible light-generated image, and which checks the connection state between the electrode on the printed circuit board (601) and the component mounted on the printed circuit board (601) by means other than by means of a visible light-generated image, characterized by, that it obtains connection information from the external view inspection device (230), which is information on the position of a connection that the electronic component has on the printed circuit board (601), wherein the connection information includes information on the height of the connection in relation to the electrode on the printed circuit board (601), which connection height is an actual measured value, and uses the connection information to determine an area for performing an inspection.

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