Control device for an internal inspection device and method for controlling an internal inspection device

Abstract

Control device (250) for controlling an internal inspection device (240) in a test system comprising an external inspection device (230) which checks the connection state between an electrode on a printed circuit board and a component mounted on the printed circuit board by soldering using visible light, and the internal inspection device (240) which checks the connection state between the electrode on the printed circuit board and the component mounted on the printed circuit board by soldering in a manner other than by visible light, characterized by a test object registration means which registers a first test object location, which is a test object location whose connection state cannot be determined by visible light, and an additional test object detection means which detects a second test object location, which is a test object location where a solder application angle (η)) at a front solder fillet formed at a joint location, is greater than a specified angle and at which joint defects are suspected by the external view inspection device (230), wherein a joint defect is suspected if at least one of the following conditions 1-3 is not met: Condition 1: a height (h) of a connection at a joint location is not higher than a specified height, Condition 2: a ratio of a length (b) of the solder fillet to a length (a) from a connection end to a solder lug end is 50% or more, and Condition 3: the solder application angle (θ) is not greater than the specified angle, and an inspection execution device that performs an inspection of the first and second test object locations.;

Description

1. Technical area

[0001] The present invention relates to a device for examining the assembly status of a component 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 mounting on the circuit board, an inspection is necessary after the solder has cooled to determine whether the components have been correctly mounted on the board. To ensure product quality, it is particularly important to precisely assess whether the connections between the component leads and the electrodes on the circuit board (solder pads) have been soldered correctly.

[0004] Two methods exist for inspecting the joint condition of components: AOI and AXI. AOI (automated optical inspection) involves using a visible light camera to photograph a test object and analyzing the images to determine the joint condition. AXI (automated X-ray inspection) irradiates the test object with X-rays, and the joint condition is determined based on the resulting X-ray image. While AOI can detect defects based on external appearance, AXI can detect defects that are not visible externally.

[0005] In recent years, the number of components such as BGA (ball grid array) or solderless components, shielded components and the like has also increased, where the connection status of the terminals cannot be checked based on the external appearance, which is why the AXI method is used more frequently.

[0006] Furthermore, it is possible to perform the inspection using both the AOI and AXI methods, thereby increasing the manufacturing quality of the printed circuit boards. Japanese patent application no. 2010-271165 describes a testing device that applies the AOI and AXI methods simultaneously, whereby the AXI method involves a defect analysis based on the AOI test results. overview

[0007] While the AXI method offers the advantage of enabling the inspection of parts that are not visible from the outside, it also has the disadvantage of a longer inspection time compared to the AOI method.

[0008] If the time required for AXI inspection is longer than the time required for production, more inspection fixtures than production lines are needed, thus increasing costs. Furthermore, if only AOI (Automated Optical Inspection) is used for inspection, non-visible parts cannot be inspected. Therefore, it is more necessary than ever to use AOI and AXI inspection methods in conjunction.

[0009] Another conceivable method involves testing only non-visible components using the AXI method, while the remaining components undergo AOI testing. However, since the AOI method determines the presence of defects solely based on external appearance, it can happen that a defect is identified despite a connection being perfectly functional, simply because the visible part appears questionable.

[0010] Due to the high density of the components, the number of components with small solder pads for connecting the terminals increases.

[0011] These components are often particularly small, so the area where the front solder joint is formed is narrow. Therefore, it can happen that while the connection can be made, a sufficient front solder joint is not formed, and when such components are tested using the AOI method, a perfectly good product can therefore be incorrectly identified as defective.

[0012] Therefore, if all components that can be tested using the AOI method are tested only using the AOI method, it may prevent the delivery of defective products, but this creates the problem of excessive quality control, as even flawless products may be identified as defective. This leads to the problem that if an AXI method is used instead of AOI for precise identification, the testing costs will increase.

[0013] The present invention was made taking into account the aforementioned problems, and its objective is to provide a technique in which a balance between testing accuracy and testing speed is achieved in a system for testing the interconnection status of components mounted on a printed circuit board.

[0014] To solve the aforementioned problem, a control device of an internal inspection device of the present invention has such a configuration that, for an object to be inspected, an inspection in the AXI method is carried out only for those points that cannot be inspected in the AOI method and those points where the inspection in the AOI method has detected a doubtful connection state.

[0015] Specifically, the control device of the internal testing device of the present invention is a control device of the internal testing device in a testing system comprising an external viewing testing device that checks the connection state between an electrode on a printed circuit board and a component mounted on the printed circuit board by soldering using visible light, and an internal testing device that checks the connection state between the electrode on the printed circuit board and the component mounted on the printed circuit board by soldering in a manner other than by visible light, characterized by a test object registration means that registers a first test object location, wherein this is a test object location whose connection state cannot be determined by visible light, and an additional test object detection means that detects a second test object location, which is a test object locationwhere connection defects are suspected by the external inspection device, and a testing device that performs an inspection of the first and second test object locations.

[0016] The first test point is one where checking the connection status with visible light is not possible, for example, because the connection is located on the back of the component or is covered by shielding. This means that the first test point requires a different type of test than visible light (internal inspection). The test point can be configured for each component and for each connection.

[0017] The second inspection point, in turn, is one where the visible light inspection revealed a suspicion of connection defects. This means that at this second inspection point, a flawless product could be identified as defective based solely on its external appearance. Therefore, it is an inspection point where it cannot be determined whether a defect exists or not, and thus it is an inspection point for which an internal inspection has been determined.

[0018] In addition to the first inspection point, which is the original inspection object, the inspection device performs an inspection at a second inspection point. The control device of the internal inspection device according to the present invention therefore does not perform an internal inspection at points where defects can be determined solely by visible light inspection, but only at points where defects cannot be determined solely by visible light inspection. In this way, a balance between inspection accuracy and inspection time can be achieved.

[0019] The second test object location can also be characterized by the fact that it is a location where the height of a connection at a joint is higher than a certain height.

[0020] If the height of a connection at a joint exceeds a certain value, it's possible that the connection is floating above the solder pad. However, depending on the solder adhesion, the connection may also be properly attached. Therefore, the external appearance alone cannot determine whether the joint is faulty or not, which is why an internal inspection is preferable.

[0021] The second test object location can also be characterized by the fact that it is a location where the length of a front plumb groove formed at the joint is shorter than a certain length, or the second test object location can also be characterized by the fact that the angle of application of plumb on the front plumb groove formed at the joint is greater than a certain angle. The second test object location can also be characterized by the fact that it is a location where the height of the front plumb groove formed at the joint is less than a certain height.

[0022] The front plumb groove is a plumb groove that is formed facing outwards at the connection.

[0023] If the solder fillet is sufficiently long and high, this indicates that the connection was properly attached to the solder lug. However, if the solder fillet is short or low, the attachment may be inadequate. It is also possible that sufficient attachment strength is achieved by a rear solder fillet (a solder fillet formed on the inside of the connection), and in this case, an internal inspection is preferably carried out to determine whether the joint is defective.

[0024] Even if the application angle of the solder (i.e., the contact angle between the solder and the solder pad) is larger than a certain angle, there is a possibility that insufficient bond strength has been achieved, which is why an internal inspection is also preferably carried out.

[0025] Furthermore, the control device of the internal inspection device according to the present invention is further characterized by a test object exclusion means that detects a third test object location, which is a test object location where the connection state has been clearly determined to be defective by the external view inspection device, and excludes the third test object location from the first test object location.

[0026] A clearly defective connection means, for example, that the connection is too high, the connection or component is missing, or a connection has been made to the wrong terminal. In these cases, an external inspection can determine whether a defect exists. Therefore, even if the object is subject to internal inspection, no internal inspection is carried out. This prevents unnecessary testing.

[0027] The internal testing device of the present invention can also be characterized in that the testing of the connection state is carried out by computed tomography using X-rays.

[0028] The present invention is particularly advantageous for controlling the internal testing device using X-rays.

[0029] The present invention can specifically be a control device for an internal testing device, comprising at least one of the means described above. The present invention can also specifically be a method for controlling the internal testing device, a program for operating the internal testing device, and a storage medium on which the program is stored.

[0030] The present invention may further specifically be a testing system comprising the external view testing device and the internal testing device.

[0031] Provided that no technical contradictions are created, the aforementioned processing operations and means can be carried out in any combination.

[0032] According to the present invention, a system for testing the connection status of components mounted on a printed circuit board can achieve a balance between testing accuracy and testing speed. Brief description of the drawings

[0033] They show:

[0034] Fig. 1. A flowchart explaining the manufacturing and testing of a circuit board using the reflow process;

[0035] Fig. 2 a view that explains an overview of an examination according to an embodiment;

[0036] Fig. 3 a view that explains the assessment of the solder joint condition;

[0037] Fig. 4 a data structure of test object information contained in a test program;

[0038] Fig. 5 a data structure of test result information that is sent to an analysis device;

[0039] Fig. 6 a second view that explains the assessment of the solder joint condition;

[0040] Fig. 7 a data structure of additional inspection information generated by the external view inspection device;

[0041] Fig. 8 an operating flow diagram of the external view inspection device;

[0042] s Fig. 9 a scale of the external view inspection device for assessing whether a defect is present or not;

[0043] Fig. 10 an operating flow diagram of the X-ray testing device;

[0044] Fig. 11 a processing flow diagram for the generation of a test object list by the X-ray inspection device; and

[0045] Fig. 12. A flowchart for a processing procedure to assess a final test result. Detailed description (system configuration)

[0046] 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 onto the surface of printed circuit boards, and a surface mount line is primarily configured with the three steps of solder paste printing, component assembly, and reflow (melting the solder).

[0047] As in Fig. As shown in Figure 1, the surface assembly line, in descending order, includes a soldering printing device as a production plant. 110 , a pick-and-place machine 120 and a reflow oven 130 provided. The soldering press device 110 is a device that uses screen printing to apply paste-like solder to the electrode section of a printed circuit board (referred to as the "solder pad"). The pick-and-place machine 120A chip placement machine is a device that holds the electrical component to be mounted on the circuit board and places the component onto the solder paste at the appropriate location; it is also known as a chip placement machine. The reflow oven 130 A heating device heats and melts the solder paste, then cools it to allow the electrical component to be soldered to the circuit board. The aforementioned production facilities 110 until 130 are connected to a production plant management device via a network (LAN). 140 connected. The production plant management device 140 is a system for managing or controlling the production plant 110 until 130The production plant management device includes functions for storing, managing, or outputting execution programs that determine the operation of the production plants (including operating sequences, production conditions, setting parameters, etc.) and log data from each production plant. 140 It also features 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 other device.

[0048] 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).

[0049] As in Fig. As shown in Figure 1, the quality assurance system of the present embodiment includes four different testing devices, namely a solder pressure testing device. 210 , a component testing device 220 , an external view inspection device 230 and an X-ray inspection device 240as well as with an examination management device 250 , an analysis device 260 and a workstation computer 270 configured.

[0050] The solder pressure testing device 210 is a device that is attached to the circuit board, which is operated by the soldering printer 110 The device checks the pressure state of the solder paste. 210The solder paste printed on the circuit board is measured two- or three-dimensionally, and the measurement results for various test points determine 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. For two-dimensional measurement of the solder paste, an image sensor (camera) can be used, while for three-dimensional measurement, laser displacement calculation, phase shift method, spatial coding method, light sectioning method, or similar techniques can be employed.

[0051] The component testing device 220 is a device that is attached to the circuit board, which is placed by the pick-and-place machine 120 The device performs a check of the arrangement of the electrical components. 220It measures the components (or 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. Test points can include, for example, a component's positional deviation, an angular deviation (rotation), a missing component (a component not being arranged), a component mix-up (arrangement of incorrect components), a polarity reversal (incorrect polarity of the electrodes on the component side and the board side), a reversal of front and back (component arranged with the front facing down), component height, and the like.As with solder pressure testing, an image sensor (camera) can be used for the two-dimensional measurement of electronic components, and for three-dimensional measurement, laser displacement calculation, a phase shift method, a spatial coding method, a light sectioning method, or similar techniques can be used. The external viewing inspection device... 230 is a device that is attached to the reflow oven 130 The circuit board being issued undergoes a soldering inspection. The external inspection device 230The solder joint is measured two- or three-dimensionally after reflow, and the measurement results for various test points determine whether a normal value (within a permissible range) is present. In addition to component testing points, the test points can also include an assessment of the solder joint shape or similar characteristics. When measuring the solder joint shape, methods such as laser offset calculation, phase shift analysis, spatial coding, light section analysis, or similar techniques can be used, as described above. Alternatively, a color highlighting method can be employed (illumination in RGB colors is shone onto the solder joint surface at different angles, and the reflected light of each color is captured by a ceiling camera, thus outputting the three-dimensional shape of the solder joint as two-dimensional color phase information).

[0052] The X-ray testing device 240This is a device (internal inspection device) that uses an X-ray image to check the condition of the solder joints on the circuit board. In the case of packaged components such as a BGA (ball grid array) or CSP (chip size package), or multilayer circuit boards, the solder joint section is hidden beneath the components or the circuit board itself. Therefore, an external inspection device is used. 230 (i.e., with images of the external appearance) the soldering condition cannot be checked. The X-ray testing device 240 is a device that compensates for these weaknesses of external testing. Test points of the X-ray testing device 240Examples of parameters that can be specified include the positional deviation of a component, the solder height, the solder volume, the solder ball diameter, the length of the trailing solder groove, or the quality of the solder joint. X-ray images, radiography images, or CT (computed tomography) images are also preferably used.

[0053] The aforementioned test devices 210 until 240 are connected to an exam management device via a network (LAN). 250 connected. The examination management device 250 is a system for managing or overarching control of the test equipment 210 until 240 , the functions for storing, managing or outputting execution programs that control the operation of the test equipment 210 until 240 determine (including test procedure, test conditions, setting parameters, etc.) and test results or log data of the individual test devices. 210 until240 exhibits.

[0054] The analysis device 260 is a system that has a function to provide the examination management device 250 compiled test results (test results of the individual steps) of the individual test devices 210 until 240 to analyze and perform a defect prediction or a defect cause assessment or the like, and has a function to provide feedback to the individual production facilities if required. 110 until 130 (to perform updates to the execution program, etc.).

[0055] The work computer 270 is a system that has a function for displaying the status of the production facilities 110 until 130 , the test results of the individual test devices 210 until 240 and the analysis results of the analysis device 260and the like, a function for modifying (editing) execution programs or test programs of the production plant management device 140 or the examination administration device 250 and has a function for checking the overall operating status of the surface assembly line.

[0056] The production plant management device 140 , the examination administration device 250 and the analysis device 260 Each of these devices can be configured in a standard computer system equipped with a CPU (central processing unit), main memory (memory), auxiliary storage (hard disk or the like), input device (keyboard, mouse, controller, touchpad or the like), display device, and the like. 140 , 250 , 260can be separate devices, or the devices 140 , 250 , 260 All of the aforementioned functions can be performed in a single computer system, and it is possible for a computer connected to any of the production facilities to 110 until 130 or test devices 210 until 240 is equipped with all the functions of the devices 140 , 250 , 260 or performs part of it. In 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. (External inspection and X-ray inspection)

[0057] Next, the details of the tests performed by the external view inspection device will be described. 230 and the X-ray testing device 240 with reference to Fig. Figure 2 describes a data flow. The test devices are devices that check whether the connection of the electrical component located on the circuit board has been correctly soldered to the solder pad of the circuit board. The test devices are arranged on a test line and configured to perform a test on a conveyed circuit board (a circuit board that is a test object because its manufacturing steps are complete).

[0058] The test devices load from the test management device. 250 a program (test program) for operating the devices and are operated by the program.

[0059] The external view inspection device 230This device, as previously described, captures an image of the printed circuit board after reflow and identifies soldering defects or their nature. Specifically, it illuminates the board with a multi-colored light source (for example, with the three colors red, green, and blue) from different angles and captures the reflected light to obtain virtual color images. This configuration results in the image showing different colors of light depending on the angle of the test object's surface. The images thus reveal clear differences in the color pattern corresponding to the shape of the solder. In this way, the shape of the connection section can be resolved two- or three-dimensionally, and the soldering condition of the components can be determined. Such an examination of images of the external appearance (images taken with visible light) is referred to in this description as external inspection.

[0060] The contents of the external view inspection device 230 The test performed will now be described in detail. As examples of circuit board testing procedures, a solder joint test and a connection test will be described. A solder joint test is an assessment test for the condition of the connection based on the shape of the solder joints. Fig. Figure 3 is a sectional view through the soldered joint where the solder lug and the terminal have been joined by soldering. When the terminal is joined to the solder lug by soldering, a front solder fillet (located on the outside of the component) and a rear solder fillet (located on the inside of the component) are formed. The rear solder fillet is difficult to see from the outside, which is why the test object of the external view inspection device is exclusively the front solder fillet.

[0061] As in Fig. As shown in Figure 3, a perfectly formed solder joint creates a wide, inclined surface from the connection to the solder eye, resembling the base of a mountain. If, however, there is a lack of solder, the inclined 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 uses this form to assess the state of the connection.

[0062] The assessment of the connection condition is carried out, for example, based on the length and height of the front solder groove or the contact angle of the solder in relation to the solder eye.

[0063] In the case of the example from Fig. 3. For example, a length a from the end of the solder lug to the end of the connection, a length b of the front solder groove and a solder contact angle θ can be obtained.

[0064] The connection test is a test in which the quality of the connection is determined based on the height of the connection. If the connection is too high, it can be determined that the connection is not connected to the solder pad, but is floating.

[0065] In the example from Fig. 3 can, for example, be obtained as a height of the connection a height h (in the present example a height from the solder lug to the surface of the end connected to the solder lug).

[0066] The examination administration device 250 stores test programs for operating the external view inspection device 230 and the X-ray testing device 240 and is a device that sends a test program to the individual test devices when required.

[0067] The test programs are programs and data for operating the test fixture and include information for defining the test sequence as well as detailed information (hereinafter referred to as "test object information") about the test object. The test programs contain, for example, commands for image processing of captured images, feature parameters extracted from the images, or evaluation criteria for comparison with the extracted feature parameters. The external view test fixture 230 and the X-ray testing device 240 Using testing programs, they analyze the recorded images, check the connection status, and output the test result.

[0068] Fig. Figure 4 shows an example of a data structure for test object information contained in a test program. The test object information includes a field that indicates, for each terminal connected to a solder lug, whether an AOI test can be performed at the corresponding location or whether an AXI test should be performed (in Fig. 4 “Test type” under “Test type information”), and the individual test devices perform tests with reference to the field.

[0069] The in Fig. The test type shown in Figure 4 can be defined for each connection, but in this embodiment, identical test types are assigned to identical components. Of course, a different test type can also be set for each connection.

[0070] When a printed circuit board is used for external inspection, 230 The external view inspection device detects the transported item. 230The board ID of the conveyed circuit board. The board ID can also be obtained from the production equipment management device. 140 The data can be captured, and if reading is possible with each capture of the circuit board, it can also be read directly from the board.

[0071] The test program corresponding to the delivered circuit board is then executed by the test management device. 250 The data is retrieved. Subsequently, with reference to the test object information in the test program, the test objects for testing in the AOI procedure are extracted from among the components mounted on the printed circuit board, and the external inspection is carried out.

[0072] Once the external inspection is complete, the external view inspection device generates 230 the in Fig. 5 shown test result information and sends it to the analysis device 260The transmitted test result is temporarily stored in the analysis device. 260 The data is saved. "Test Type" is a field for registering the type of test (AOI or AXI), and "Test Result" is a field for registering the test result (pass or fail). "Measurement Information" is a field for registering information such as the measured values ​​obtained during the test.

[0073] Next, the X-ray testing device will be installed. 240 be described. One of the external view inspection devices. 230 The tested circuit board is used for the X-ray testing device. 240 transported. At the X-ray inspection device 240Radioactive X-rays are shone onto the exterior of the fully soldered circuit board to scan it, and by combining a plurality of images obtained by scanning, an image is created that shows the internal structure, and thus the test is carried out.

[0074] In the X-ray inspection device 240 The images produced can be, as mentioned previously, radiological images or three-dimensional images obtained using computed tomography. At the X-ray testing device 240 Forms of plumb lines that are not immediately visible from the outside can be detected.

[0075] When a circuit board is used for the X-ray inspection device 240 The X-ray inspection device detects the transported item. 240 The circuit board ID of the printed circuit board is retrieved, and the test program corresponding to the delivered circuit board is called from the test management device. 250ab. Subsequently, with reference to the test object information in the test program, the test objects for testing in the AXI method are extracted from among the components mounted on the printed circuit board, and an X-ray inspection (internal inspection) is carried out.

[0076] After completion of the X-ray inspection, the inspection management device generates 250 as well as the external view inspection device 230 the in Fig. 5 shown test result information and sends it to the analysis device 260 The transmitted test result is processed in the analysis device. 260 stored and used to determine the final test result. (Assessment of the need for an additional examination)

[0077] According to the configuration above, at test object locations where inspection based on external appearance is possible, an inspection is carried out using the AOI procedure, and at test object locations where inspection based on external appearance is not possible, an inspection can be carried out using the AXI procedure.

[0078] The problem here is that, during AOI testing, there is a risk that a perfectly good product will be classified as defective, thus overemphasizing its quality. This problem will be addressed with reference to… Fig. 6 will be described.

[0079] The quality of the connection is determined based on the connection height, the length ratio of the plumb line, and the plumb angle. For example, if: Condition 1: Connection height of 0.2 mm or less Condition 2: Ratio of the solder fillet length to the length from the connection end to the solder lug end of 50% or more Condition 3: If the plumb line angle is 45 degrees or less, the joint receives a rating of "Perfect". When transcribing using the symbols from Fig. 3. This means that if the following conditions are met: Condition 1: h ≤ 0.2 mm Condition 2: b / a ≥ 0.5 Condition 3: θ ≤ 45° The assessment is "Flawless", while if even one of the conditions is not met, the assessment is "Deficient".

[0080] Referring to Fig. Now, let's look at different patterns. The pattern from Fig. 6(A) All conditions are met, therefore the connection status is determined to be "Perfect". A correct assessment using AOI methods is possible for this sample.

[0081] In the case of the pattern from Fig. In contrast, the connection height of 6(B) is 0.25 mm, which is outside the reference range, and therefore the solder joint condition is determined to be "Deficient". Because the connection position is too high, there is a possibility of a defective connection.

[0082] However, since the joint strength is determined by the contact area between the solder pad and the terminal, a sufficient contact area can be achieved even with a high terminal position by properly forming the rear solder groove, so there is no quality problem. However, since the condition of the rear solder groove cannot be determined solely based on its external appearance, and the quality cannot be determined by the AOI test, the assessment must necessarily be "Deficient". Regarding the sample from Fig. 6(C), for example, has the same connection height as in Fig. 6(B) 0.25 mm, but here the connection floats completely above the solder lug, and there is no connection.

[0083] Next, the pattern will be made of Fig. 6(D) are considered. While there is no problem with the connection height in this sample, the shape of the plumb fillet does not meet the requirement and is therefore classified as "Deficient". However, as already mentioned, even if the shape of the front plumb fillet is not as specified, there is no quality problem as long as a sufficient connection surface has been achieved. In the case of this sample, the rear plumb fillet is correctly formed, so a sufficient connection surface has been achieved and there is no quality problem. However, since, as with the sample from Fig. 6(B) Since the shape of the rear plumb line cannot be determined from the external appearance, the quality cannot be determined by an AOI test, and therefore the assessment must necessarily be “Deficient”.

[0084] The pattern from Fig. 6(E) The component is not installed. Since the connection itself cannot be found in this case, the defect can be correctly identified by testing using the AOI method.

[0085] If the five patterns described above are examined using the AOI procedure, in practice the result is the same for all patterns except the one from Fig. 6(A) the assessment ‘Deficient’ although the samples from Fig. 6(A), Fig. 6(B) and Fig. 6(D) are actually flawless. That is, the quality is overemphasized.

[0086] In the quality assurance system of the embodiment, therefore, in the event that the external view inspection device 230 If the test is performed using the AOI procedure and the quality of the connection state cannot be determined, information is generated stating "additional testing required" and sent to the X-ray testing device. 240 sent, whereupon the X-ray inspection device 240 In addition to the original test object location, an inspection using the AXI procedure is also carried out at the test object location designated as "additional inspection required".

[0087] Fig. Figure 7 shows the data structure of the additional inspection information provided by the external view inspection device. 230 to the X-ray testing device 240 to be sent. The additional test information is information that indicates a connection where an additional test by X-ray is necessary.

[0088] According to this configuration, the quality assurance system of the embodiment, during AOI testing, only classifies products as "defective" if a defect can be detected based on their external appearance, while those whose quality cannot be determined based on external appearance can be subjected to AXI testing. This allows for a reliable assessment of the joint condition quality with minimal testing effort.

[0089] In Fig. Section 7 provides examples of information for specifying a connection that requires additional testing; however, as long as the additional testing information can indicate the location where additional testing is required, it can take any form. For example, it could also be information that only specifies the component. (Processing flow diagram)

[0090] Next, a flowchart of the processing by the external view inspection device will be shown. 230 and the X-ray testing device 240 be described.

[0091] Fig. 8 is a flowchart of an inspection processing procedure using the external view inspection device. 230 The flowchart from Fig. Step 8 is executed for all mounted components after the detection of a delivered circuit board.

[0092] First, in step S11, an external inspection of the component bodies mounted on the circuit board is performed. This step looks for obvious defects such as a missing component or incorrect polarity, for which a solder joint condition check is not yet required. The inspection is carried out for all components with reference to the test object information in the test program (in Fig. 4 “Component information”) was carried out.

[0093] Next, in step S12, it is determined whether the component body is defective, and if so, a transition to step S17 takes place, and the in Fig. The test result information shown in section 5 is generated and stored in the analyzer. 260 saved.

[0094] In step S13, the connection status of a component under test is checked against the solder pad on the circuit board. The test refers to the "Test type" field in the test object information and is performed on components that have been specified as being capable of external testing.

[0095] If, as a result, all connection points of the component in question are flawless and the assessment is “Flawless” (step S14 – Yes), a transition to step S17 takes place, and the test result information for the component in question is generated and stored in the analysis device. 260 saved.

[0096] However, if a defect is suspected at a connection (step S14 – No), the process proceeds to step S15. A defect is suspected if, as described above, at least one of the conditions is met. Condition 1: Connection height of 0.2 mm or less Condition 2: Ratio of the solder fillet length to the length from the connection end to the solder lug end of 50% or more Condition 3: The plumb line angle of 45 degrees or less is not met.

[0097] Step S15 determines whether the detected deviation indicates an obvious connection defect. An obvious connection defect is one that can only be identified through testing using the AOI procedure.

[0098] For example, if the thickness of the printed solder paste and the thickness of the component lead are each only up to 0.15 mm, and the measured lead height is 0.4 mm, it is obvious that there is no connection between the lead and the solder pad. In such a case, no test needs to be performed using the AXI procedure to determine the defect, which is why a transition to step S17 occurs and the test result information for the component in question is generated.

[0099] If the fault cannot be identified in step S15, "additional inspection required" is determined for the component in question. In step S16, the component information is added to the additional inspection information, such as that from Fig. 7 added.

[0100] Fig. Figure 9 shows the assessment basis for the components of the embodiment in the form of a table.

[0101] Next, with reference to Fig. 10. A flowchart of the test processing by the X-ray testing device 240 be described. The flowchart from Fig. Procedure 10 is executed when a printed circuit board is transported to the X-ray inspection device.

[0102] First, in step S21, the board ID of the conveyed circuit board is recorded. As mentioned previously, the board ID can also be obtained from the production equipment management system. 140 or similar, or read directly from the circuit board.

[0103] Next, in step S22, the additional test information for the printed circuit board is retrieved. Then, in step S23, a test object list is generated, which is a list of the objects intended for internal inspection.

[0104] Step S23 is a step in which a list of inspection objects is generated. This list includes inspection object locations where an X-ray inspection must always be performed, and inspection object locations where the defect could not be detected by the external visual inspection device. The processing in step S23 should be based on the flowchart from Fig. Section 11 describes the processing of this step in detail.

[0105] When processing moves to step S23, the first component ID for the object circuit board is selected in step S231 with reference to the test object information.

[0106] Next, in step S232, the test type for the connections of the selected component is retrieved, followed by the determination of the test type in step S233. There are three test types: "Always perform AXI test," "AXI test if additional testing is necessary," and "Always perform AOI test." These types will now be described. (1) Always perform AXI testing

[0107] If the selected component cannot be inspected based on its external appearance and therefore an X-ray inspection is necessary, the inspection type for the component's connections is "Always perform AXI inspection." In this case, the process proceeds to step S234, and, with reference to the inspection result information, it is determined whether the component in question was found to be "Defective" during the AOI inspection. If a defect was found during the AOI inspection, this means that a component is missing or a fatal connection error exists, and therefore no X-ray inspection is performed on the component.

[0108] If no defect is found for the component, all connection numbers of the component are added to the test object list in step S235. (2) AXI examination if additional testing is necessary

[0109] If the component can be inspected based on its external appearance, but the AOI inspection alone cannot determine whether a defect exists, the inspection type for the component's terminals is "AXI inspection when additional inspection is required." In this case, the process proceeds to step S236, and it is checked whether the relevant component ID is included in the additional inspection information generated by the external view inspection device. If so, the corresponding terminal number of the relevant component is added to the inspection item list (step S237). (3) Always perform AOI checks

[0110] If the component can be inspected based on its external appearance and a defect can be determined solely by AOI testing, the inspection type for the component's connections is "Always perform AOI inspection". Since no X-ray inspection is necessary in this case, the component is not added to the inspection list.

[0111] Once processing for the selected component is complete, the system checks, with reference to the test object information, whether another component is present (step S238). If so, the next component ID is selected (step S239), and processing continues. If no further component is present, processing ends.

[0112] Returning to Fig. The description continues from step S24.

[0113] In step S24, the first component on the inspection list is selected, and in step S25, an X-ray inspection is carried out for this component.

[0114] In step S26, the system checks whether another component is present on the inspection list. If so, the next component is selected (step S28), and the X-ray inspection continues. If no further component is present, the inspection result is generated (step S27), and processing ends.

[0115] Once processing is complete, this means that the result of the AOI or AXI inspection has been generated for each individual test object location. The following section will describe a processing step in which a final inspection result for the printed circuit board is determined based on these inspection results.

[0116] Fig. Figure 12 shows a flowchart of processing by the analysis device. 260to determine a final exam result. This processing is performed for each entry in the exam result information ( Fig. 5) carried out.

[0117] First, in step S41, the result of the inspection in the AOI procedure is retrieved. If the inspection result here is "Flawless" (step S42), then the final inspection result will also be "Flawless" (step S43).

[0118] In this case, the quality can be determined solely through testing using the AOI procedure.

[0119] If the result of the AOI procedure inspection is "Deficient" (step S42 – No), the process proceeds to step S44, and it is checked whether an AXI procedure inspection result exists. If no AXI procedure inspection result exists, the deficiency could not be identified, or there was an obvious deficiency, which is why the final inspection result is "Deficient" (step S45).

[0120] If a result from an AXI inspection can be retrieved and the initial result is "Flawless," then the final inspection result is also "Flawless." In this case, although no defect could be detected during the external inspection, the X-ray inspection revealed that no problem existed. Furthermore, if the AXI inspection result is "Deficient," then, of course, the final inspection result is also "Deficient."

[0121] Circuit boards where even one of the connections is passed through the analysis device 260 Components identified as "Defective" based on the aforementioned processing will be classified as defective products. If all connections of the assembled components are found to be "Perfect," the circuit board will be classified as a flawless product.

[0122] The final test result can be sent to the user via their work computer. 270The results can be communicated, or the products can be sorted into satisfactory and defective products after testing without notification. If notification is given to the user, the test step in which a defect was detected (AOI or AXI) can be displayed for each test item (component or connection), or the test result can be displayed for each test step.

[0123] Furthermore, the additional inspection information (i.e., information about an object where the defect could not be determined during the AOI inspection and an AXI inspection was carried out) can be provided to the user. This allows the user to see which process was used to determine the quality, thereby potentially reducing the number of visual inspections or similar procedures.

[0124] The additional exam information can be displayed simultaneously with the final exam result or at specific times during the exam.

[0125] In the quality assurance system of this embodiment, as described above, an inspection using the external viewing device is carried out at locations where defects can be detected by visible light inspection (external inspection), while an X-ray inspection is only performed at locations where visible light inspection is not possible and where the defect could not be detected by external inspection. In this way, the inspection effort can be minimized, and highly reliable inspection results can be obtained. This means that investment costs and costs associated with an excessive emphasis on quality (scrap costs, etc.) can be reduced. (Examples of variations)

[0126] The description of the embodiment was provided 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.

[0127] In the description of the embodiment, the test devices were, for example, provided by the test management device. 250 Stored programs are operated, but the use of a common test management device is not strictly necessary as long as the test devices can be operated together. For example, the programs can be stored in the memories of the individual test devices and executed by a built-in processor. Instead of the analysis device 260Furthermore, a storage device configured with a hard disk or non-volatile memory or the like may be used, and a user of the system may assess the final test result with reference to the test result information.

[0128] In the description of the embodiment, the common test object information is furthermore sent to the external inspection device and the X-ray inspection device, and the inspection devices determine, with reference to the inspection type, whether an inspection is necessary or not; however, the test object information does not necessarily have to be shared. For example, the external inspection device may contain test object information in which only the objects for which an inspection is carried out using the AOI method are registered. However, since potentially all components are eligible for X-ray inspection, the X-ray inspection device preferably contains test object information in which all test object locations are registered.

[0129] In the description from Fig.For connections of identical components, the same test type is always set (11), but the test type can also be different for each connection. In this case, only the connection for which testing using the AXI procedure has been decided can be added to the test object list.

[0130] In the external inspection device of the embodiment, the connection condition was further determined using three criteria: connection height, plumb fillet length ratio, and application angle. However, other criteria can also be used, provided they are based on the external appearance. For example, the length of a connection or the height of the plumb fillet itself can be measured to perform the determination. QUOTES INCLUDED IN THE DESCRIPTION

[0131] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0132] JP 2010-271165

[0006]

Claims

[1] Control device for controlling an internal inspection device in a test system comprising an external 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 soldering using visible light, and the internal inspection device that checks the connection state between the electrode on the printed circuit board and the component mounted on the printed circuit board by soldering in a manner other than by visible light, characterized by a test object registration means that registers a first test object location, which is a test object location whose connection state cannot be determined by visible light, an additional test object detection means that detects a second test object location, which is a test object location where connection defects are suspected by the external inspection device, and a test execution means.which conducts an examination of the first and second test object locations. [2] Control device for controlling an internal testing device according to claim 1, characterized by that the second test object location is a location where the height of a connection at a junction is higher than a certain height. [3] Control device for controlling an internal testing device according to claim 1 or 2, characterized by that the second test object location is a location where the length of a front plumb line formed at the joint is less than a certain length. [4] Control device for controlling an internal testing device according to one of claims 1 to 3, characterized by that the second test object location is a location where the plumb line angle at the front plumb groove formed at the joint is greater than a certain angle. [5] Control device for controlling an internal testing device according to any one of claims 1 to 4, characterized by that the second test object location is a location where the height of the front plumb line formed at the joint is less than a certain height. [6] Control device for controlling an internal inspection device according to one of claims 1 to 5, further characterized by a test object exclusion means that detects a third test object location, which is a test object location where the external view inspection device has clearly determined that the connection state is defective, and excludes the third test object location from the first test object location. [7] Control device for controlling an internal testing device according to any one of claims 1 to 6, characterized by that the internal testing device performs the inspection of the connection condition by computed tomography using X-rays. [8] Method for controlling an internal inspection device in a test system comprising an external inspection device which checks the connection state between an electrode on a printed circuit board and a component mounted on the printed circuit board by soldering by means of visible light, and the internal inspection device which checks the connection state between the electrode on the printed circuit board and the component mounted on the printed circuit board by means other than by visible light, characterized by the following steps: Detecting a first test object location, which is a test object location whose connection state cannot be determined by visible light, Capturing an additional test object by capturing a second test object location, which is a test object location where connection defects are suspected by the external view inspection device, and Performing an inspection of the first and second test object locations. [9] Program for executing the steps of the method for controlling an internal inspection device according to claim 8 on a computer. [10] Test system comprising an external inspection device and an internal inspection device, wherein the connection state between an electrode on a printed circuit board and a component mounted on the printed circuit board by soldering is tested, characterized bythat the external inspection device comprises a first inspection means which inspects a test object location by visible light, and an additional inspection information transmitter which sends a test object location, where a connection defect is suspected as a result of the inspection by the first inspection means, as an additional test object location to the internal inspection device, and the internal inspection device comprises a second inspection means which performs an inspection at a test object location whose connection state cannot be determined by visible light and at the additional test object location detected by the external inspection device, in a manner other than by visible light.

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