Inspection system, inspection method and storage medium

Abstract

An inspection system is an inspection system for a component mounting substrate (O) on which an electronic component having leads is insertedly mounted, characterized in that it comprises: an X-ray generating unit (92); an X-ray photographing unit (93); a three-dimensional data generating unit (913), which uses information of a plurality of X-ray images photographed by the X-ray photographing unit to generate three-dimensional data of an area at least including a soldering portion of the electronic component insertedly mounted on the component mounting substrate; a lead area estimating unit (914), which uses the three-dimensional data to estimate the lead area at a specified horizontal fault position of a solder filling portion filled with solder in the soldering portion; and a gap area determining unit (915), which uses the information estimated by the lead area estimating unit to determine the gap area at a specified horizontal fault position of the solder filling portion.

Description

Technical Field

[0001] The present invention relates to an X-ray inspection system, an inspection method using X-rays, and a program. Background Art

[0002] Conventionally, in the technical field of component mounting substrate inspection, it is known to inspect an object using X-rays in order to inspect portions that cannot be inspected from the appearance of the object (eg, Patent Document 1).

[0003] Patent Document 1 discloses a technique for using X-ray images to determine the presence of voids (air bubbles) generated when plating is applied to through-holes in component mounting substrates. Specifically, multiple X-ray images of the through-holes, taken from different directions, are used to generate reconstruction information that defines a value corresponding to the amount of X-ray absorption at each coordinate in three-dimensional space. The technique then extracts a feature specific to voids from this reconstruction information and uses this feature information to determine the presence of voids in the filled portion.

[0004] According to the technology described in Patent Document 1, it is possible to detect voids generated inside the plating layer filling the through-hole (that is, a portion that cannot be confirmed from the appearance).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-45164 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] Furthermore, some component mounting substrates have electronic component leads inserted (penetrated) into through-holes and soldered (hereinafter referred to as insert mounting). During soldering, voids may be formed inside the solder filling the through-holes.

[0010] It is known that if voids exist within the solder, for example if the voids are concentrated in specific locations, disadvantages such as current obstruction and poor conduction are likely to occur, and the strength of the solder is reduced, which can easily lead to cracks (breaks, chips).

[0011] Therefore, when inspecting a substrate with lead components mounted thereon, it is necessary to determine quality based on the presence, size, and position of voids within the solder. However, voids within the solder cannot be confirmed from the outside.

[0012] Furthermore, voids within the solder of through-holes where components are inserted and mounted appear with the same brightness as the component leads on X-ray images, making it difficult to appropriately detect only voids based on feature values. Consequently, even when using X-ray images for inspection, as in the technique described in Patent Document 1, leads can be mistakenly detected as voids, leading to over-inspections (excessive failure determinations) and reduced inspection efficiency.

[0013] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a technology for accurately detecting voids in solder filled in through-holes of a component mounting board in which leads of electronic components are mounted by inserting them into through-holes.

[0014] Means for solving problems

[0015] In order to achieve the above-mentioned object, the present invention adopts the following structure.

[0016] The inspection system of the present invention is an inspection system for a component mounting substrate on which an electronic component having leads is insertedly mounted, the inspection system comprising: an X-ray generating unit that irradiates the component mounting substrate with X-rays; an X-ray photographing unit that photographs the X-rays that have passed through the component mounting substrate; a three-dimensional data generating unit that uses information from multiple X-ray images photographed by the X-ray photographing unit to generate three-dimensional data of an area of ​​at least a soldering portion of the electronic component insertedly mounted on the component mounting substrate; a lead area estimating unit that uses the three-dimensional data to estimate the lead area at a specified horizontal fault position of a solder filling portion filled with solder in the soldering portion; and a gap area determining unit that uses the information estimated by the lead area estimating unit to determine the gap area at a specified horizontal fault position of the solder filling portion.

[0017] Here, the term "soldering portion of an electronic component" also includes the portion of the electronic component lead protruding from a through-hole. Furthermore, the term "predetermined horizontal fracture position of the solder-filled portion" refers to any position in the thickness direction of the component mounting substrate where solder is filled. This position can be predetermined or set for each inspection.

[0018] With this structure, even in insert components such as leads inserted into through-holes, even if the leads are made of a material that does not absorb X-rays well, it is possible to infer the lead region where solder is present and detect only voids. This reduces the chance of leads within solder being mistakenly detected as voids, preventing a decrease in inspection efficiency due to over-detection of voids.

[0019] In addition, the lead area estimation unit may also include a lead center of gravity calculation unit, which calculates the center of gravity position of the lead at a specified horizontal tomographic position of the solder-filled portion based on multiple horizontal tomographic images of the lead protruding from both ends of the through-hole filled with solder in the welding portion, and the lead area estimation unit estimates the lead area at the specified horizontal tomographic position of the solder-filled portion using at least the information calculated by the lead center of gravity calculation unit.

[0020] Because the lead protruding from the through-hole is not covered by solder, it can be clearly identified in the X-ray image compared to the lead within the solder-filled area. Therefore, the center of gravity of the lead, which is clearly identified in the horizontal slice image of the lead protruding from each end of the through-hole, can be determined. Based on this information, the center of gravity position of the lead at a predetermined horizontal slice position of the solder-filled area can be calculated.

[0021] In addition, the lead area estimation unit may also include a lead area calculation unit, which calculates the area of ​​the lead at a specified horizontal section position of the solder-filled portion based on a plurality of horizontal section images of the lead protruding from both ends of the through-hole filled with solder in the welding portion, and the lead area estimation unit estimates the lead area at the specified horizontal section position of the solder-filled portion using at least the information calculated by the lead area calculation unit.

[0022] Based on the clearly identified lead shapes in horizontal slice images of the lead portions protruding from both ends of the through-hole, the lead area can be determined, not just at the lead's center of gravity. Based on this information, the lead area at a predetermined horizontal slice position within the solder fillet can be calculated.

[0023] In addition, it may be that the inspection system also has a storage unit for storing at least information related to the specifications of the electronic component, and the lead area estimation unit also has a lead area determination unit, which determines the area of ​​the lead at the specified horizontal fault position of the solder filling portion based on the information related to the specifications of the electronic component stored in the storage unit, and the lead area estimation unit uses at least the information determined by the lead area determination unit to estimate the lead area at the specified horizontal fault position of the solder filling portion.

[0024] The area of ​​the lead of the electronic component can be obtained from the specification information of the component. Therefore, by using such external information, the area of ​​the lead at the horizontal fracture position of the solder filling portion can be determined with high accuracy.

[0025] As described above, the lead region estimation unit can estimate the lead region at a predetermined horizontal cross-sectional position of the solder filling portion with high accuracy by using the center of gravity position and area of ​​the lead at the predetermined horizontal cross-sectional position.

[0026] Furthermore, the void region determining unit may determine the void region at the predetermined horizontal slice position of the solder filling portion by performing masking processing on the lead region estimated by the lead region estimating unit on the horizontal slice image indicating the predetermined horizontal slice position.

[0027] According to this configuration, the void region can be detected with high accuracy by excluding the lead region that cannot be distinguished from the void region in terms of feature quantity from the horizontal slice image showing the predetermined horizontal slice position of the solder filling portion.

[0028] In addition, the inspection system may also include: a user confirmation image generation unit, which generates a user confirmation image, wherein the user confirmation image at least shows a state in which the estimated lead area is masked for the horizontal tomographic image representing the specified horizontal tomographic position; and an image display unit, which at least displays the user confirmation image.

[0029] If the user confirmation image described above can be displayed, the user can confirm the specific condition of the inspection target area and the appropriateness of the good / bad judgment results, even for areas that cannot be confirmed based on appearance. Furthermore, when setting inspection standards before an inspection (hereinafter referred to as "teaching"), the actual condition of the inspection target area and the area to be measured can be confirmed, thereby improving user convenience.

[0030] The inspection system may further include an inspection unit configured to determine the quality of the component mounting substrate based on parameters related to the void area determined by the void area determination unit. Parameters related to the void area may include, for example, the area, volume, or position of the void area.

[0031] Alternatively, the inspection system may further include a void volume calculation unit that calculates the volume of voids within the solder-filled portion based on a plurality of horizontal slice images showing different horizontal slice positions within the solder-filled portion where the void region has been identified by the void region identification unit. Furthermore, the quality of the component-mounted substrate may be determined based on the volume of the voids within the solder-filled portion calculated by the void volume calculation unit. This configuration allows for a three-dimensional understanding of the void region, rather than a plan view, and further improves inspection accuracy.

[0032] Furthermore, the present invention can also be understood as an inspection management device including the three-dimensional data generating unit, the lead region estimating unit, and the gap region specifying unit.

[0033] In addition, the inspection method of the present invention is an inspection method for a component mounting substrate on which an electronic component having leads is insertedly mounted, the inspection method comprising: an image acquisition step of acquiring a plurality of X-ray images obtained by photographing the component mounting substrate using X-rays; a three-dimensional data generation step of using information from the plurality of X-ray images to generate three-dimensional data of an area including at least a soldering portion of the electronic component insertedly mounted on the component mounting substrate; a lead area estimation step of using the three-dimensional data to estimate the lead area at a specified horizontal fault position of a solder-filled portion filled with solder in the soldering portion; and a gap area determination step of using the information estimated in the lead area estimation step to determine the gap area at a specified horizontal fault position of the solder-filled portion.

[0034] Furthermore, the present invention can also be understood as a program for causing a computer to execute the above-mentioned method, or a computer-readable recording medium on which such a program is non-transitorily recorded.

[0035] Furthermore, the above-mentioned structures and processes can be combined with each other to constitute the present invention as long as no technical contradiction occurs.

[0036] Effects of the Invention

[0037] According to the present invention, it is possible to provide a technique for accurately detecting voids in solder filled in through-holes of a component mounting board on which electronic components are mounted with leads inserted into through-holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] [ Figure 1 ] Figure 1 This is a schematic diagram showing a schematic configuration of an X-ray inspection apparatus according to an application example of the present invention.

[0039] [ Figure 2 ] Figure 2 This is a flowchart showing the flow of gap inspection processing in the X-ray inspection apparatus according to an application example of the present invention.

[0040] [ Figure 3 ] Figure 3 This is a block diagram showing a schematic configuration of an X-ray inspection system according to the first embodiment.

[0041] [ Figure 4 ] Figure 4 This is an explanatory diagram showing the relationship between a schematic cross-sectional view of the vicinity of a soldering portion of a component mounted on a substrate, three-dimensional data of the corresponding portion, and a vertical slice image generated based on the three-dimensional data. Figure 4(A) is a schematic cross-sectional view showing the vicinity of the soldering portion of the substrate mounting component. Figure 4 (B) shows the three-dimensional data near the weld area. Figure 4 (C) shows a vertical slice image generated based on the three-dimensional data.

[0042] [ Figure 5 ] Figure 5 This is an explanatory diagram of a horizontal cross-sectional image of an extracted lead portion in the X-ray inspection system according to the first embodiment.

[0043] [ Figure 6 ] Figure 6 (A) is a diagram showing a horizontal cross-sectional image indicating a void candidate at a designated slice position in the X-ray inspection system according to the first embodiment. Figure 6 (B) is a diagram showing an estimated lead region of a designated fault position estimated by the lead region estimation unit of the first embodiment. Figure 6 (C) is a diagram showing a state where the estimated lead area is overlapped with the gap candidate.

[0044] [ Figure 7 ] Figure 7 This is a diagram showing an example of a user confirmation image in the X-ray inspection system according to the first embodiment.

[0045] [ Figure 8 ] Figure 8 This is a flowchart showing the flow of gap inspection processing in the X-ray inspection system according to the first embodiment.

[0046] [ Figure 9 ] Figure 9 This is a block diagram showing a schematic configuration of an X-ray inspection system according to a modified example of the first embodiment.

[0047] [ Figure 10 ] Figure 10 This is a block diagram showing a schematic configuration of an X-ray inspection system according to a second embodiment.

[0048] [ Figure 11 ] Figure 11 This is a flowchart showing the flow of gap inspection processing in the X-ray inspection system according to the second embodiment.

[0049] [ Figure 12 ] Figure 12 This is a diagram showing an example of a user confirmation image in the X-ray inspection system according to the second embodiment. Figure 12 (A) is a diagram showing a horizontal tomographic image (ie, an XY cross-sectional image) at a predetermined tomographic position of a component mounting substrate. Figure 12 (B) is a diagram showing an XZ cross-sectional image of a region including a solder filling portion of the component mounting substrate. Figure 12(C) is a diagram showing a YZ cross-sectional image of a region including a solder filling portion of the component mounting substrate. DETAILED DESCRIPTION

[0050] Application Examples

[0051] (Structure of Application Example)

[0052] The following describes an example embodiment of the present invention. The present invention can be applied as an X-ray inspection device for performing X-ray imaging of a component mounting substrate on which electronic components having leads are inserted and mounted, and inspecting the solder joints of the components for gaps based on the captured images. It should be noted that the solder joints referred to herein include through-holes filled with solder through which component leads are inserted, and the leads protruding from the through-holes.

[0053] Figure 1 1 is a schematic diagram showing a schematic configuration of an X-ray inspection apparatus 9 according to this application example. The X-ray inspection apparatus 9 is generally configured to include a control terminal 91 and an imaging unit 94 including an X-ray source 92 and an X-ray camera 93 .

[0054] The control terminal 91 can be composed of, for example, a general-purpose computer, and includes functional units such as a drive control unit 911 , a storage unit 912 , a three-dimensional data generation unit 913 , a lead region estimation unit 914 , a gap region determination unit 915 , and an inspection unit 916 .

[0055] An X-ray source 92 irradiates an inspection object O, which is conveyed by conveyor rollers (not shown), with X-rays, and an X-ray camera 93 captures X-rays that have passed through the component mounting substrate O, which is the inspection object. The X-ray source 92 is movable via an X-stage 921 and a Y-stage 922, and the X-ray camera 93 is movable via an X-stage 931 and a Y-stage 932. The X-ray source 92 and the X-ray camera 93 are movable on circular orbits C1 and C2, respectively, via these stages, and capture images at various positions along the orbits.

[0056] The drive control unit 911 controls the driving of each unit constituting the X-ray inspection apparatus 9. Thus, the X-ray inspection apparatus 9 changes the relative positions of the component mounting substrate O, the X-ray source 92, and the X-ray camera 93, and images the component mounting substrate O from a plurality of imaging positions.

[0057] The storage unit 912 stores at least information on the component mounting substrate O (eg, component type, shape, size, etc.) and information on inspection criteria such as thresholds. Various data such as programs for controlling the inspection apparatus may also be stored.

[0058] The three-dimensional data generator 913 generates three-dimensional data of at least the welded portion based on the multiple X-ray images captured as described above. The method for generating (constructing) this data can be applied to well-known technologies such as CT (Computed Tomography) and tomosynthesis, so a detailed description is omitted.

[0059] The lead region estimation unit 914 estimates the lead region at a predetermined horizontal slice position (hereinafter referred to as a designated slice position) of the portion filled with solder using the three-dimensional data generated by the three-dimensional data generation unit 913 .

[0060] The gap region specifying unit 915 specifies the gap region of the designated fault position based on the three-dimensional data generated by the three-dimensional data generating unit 913 and the information on the lead region estimated by the lead region estimating unit 914 .

[0061] The inspection unit 916 performs an inspection to determine whether the component mounting substrate O is good or not by comparing the inspection benchmark (e.g., a threshold value related to the area of ​​the gap) stored in the storage unit 912 and the parameters of the gap area determined by the gap area determination unit 915 (e.g., the area of ​​the gap area).

[0062] (Processing Flow)

[0063] Figure 2 The following describes the steps involved in the various processes for void inspection performed by the X-ray inspection apparatus 9 in this application example. First, the X-ray inspection apparatus 9 performs X-ray imaging of the component mounting substrate O from multiple different positions, acquiring multiple X-ray image data sets (S901). Next, the X-ray inspection apparatus 9 generates three-dimensional data of the welded portion of the component mounting substrate O based on the multiple X-ray image data sets acquired in step S901 (S902).

[0064] The X-ray inspection apparatus 9 then extracts multiple horizontal slice images of the lead portion not covered by solder from the three-dimensional data generated in step S902 and detects the lead region in these horizontal slice images (S903). For example, multiple horizontal slice images can be extracted for each lead protruding from each end of the through-hole.

[0065] The X-ray inspection apparatus 9 further performs a process of estimating the lead region at the designated fault position using the three-dimensional data generated in step S902 and the information on the lead region detected in step S903 ( S904 ).

[0066] The X-ray inspection apparatus 9 then performs processing to identify a void region at a designated fault position based on the three-dimensional data generated in step S902 and the information on the lead region estimated in step S904 ( S905 ).

[0067] The X-ray inspection device 9 then performs a void inspection of the component mounting substrate based on the information about the void area identified in step S905 (S906), completing the series of processing steps. The inspection content can also be determined by comparing the inspection reference of the solder fillet, which is pre-stored in the storage unit 912, with the information obtained from the identified void area, to determine whether the component mounting substrate O is good or bad.

[0068] In addition, before executing the inspection of step S906 , the processing of step S904 and step S905 may be repeated, and after determining the gap regions at the positions of multiple horizontal faults, the inspection may be performed based on the information of the multiple gap regions.

[0069] According to the X-ray inspection apparatus 9 of this application example, the void region and the lead region inside the solder that cannot be confirmed from the appearance can be recognized and specified, and over-inspection of voids can be suppressed.

[0070] <Implementation Method 1>

[0071] Next, based on Figures 3 to 8 , a more detailed example of the mode for implementing the present invention is described. However, the size, material, shape, relative arrangement, etc. of the components described in the embodiment do not mean that the scope of the present invention is limited to them unless otherwise specified.

[0072] (System Structure)

[0073] Figure 3 This is a schematic block diagram showing the functional configuration of an X-ray inspection system 1 according to this embodiment. Although not shown, the X-ray inspection system 1 according to this embodiment includes a CT apparatus and an information processing terminal, and is used to inspect component mounting substrates on which lead components are inserted.

[0074] The CT apparatus includes an X-ray source 11, an X-ray camera 12, and a table 13 that holds a component mounting substrate to be inspected. By relatively moving these components, tomographic images can be acquired at different positions (and orientations) on the component mounting substrate. The CT apparatus can employ any desired known technology, and therefore, a detailed description of the X-ray source 11, X-ray camera 12, and table 13 will be omitted.

[0075] The information processing terminal can be a general-purpose computer including a processor (not shown) such as a CPU or DSP, a main storage unit such as a read-only memory (ROM) and a random access memory (RAM), a storage unit 27 including auxiliary storage units such as an EPROM, a hard disk drive (HDD), and removable media, an input unit such as a keyboard and a mouse (not shown), and an output unit 28 such as a liquid crystal display. Furthermore, the information processing terminal may be composed of a single computer or a plurality of computers operating in conjunction with each other.

[0076] The auxiliary storage unit stores an operating system (OS), various programs, various information related to the inspection object, various inspection standards, etc. These programs are loaded into the working area of ​​the main storage unit and executed. The execution of these programs controls the various components, thereby realizing the functional units that achieve the specified purpose, as described below. Furthermore, some or all of these functional units can be implemented using hardware circuits such as ASICs and FPGAs.

[0077] Next, the functional units of the information processing terminal will be described. The information processing terminal includes a control unit 21, a three-dimensional data generator 22, a lead region estimation unit 23, a gap region determination unit 24, a quality determination unit 25, and a user confirmation image generation unit 26. The control unit 21 is responsible for controlling various components of the CT apparatus and the information processing terminal, such as driving the X-ray source 11, X-ray camera 12, and table 13, controlling input devices, and controlling output to the output unit 28.

[0078] The three-dimensional data generator 22 generates data (hereinafter also referred to as three-dimensional data) of a three-dimensional shape of a region including at least a solder joint where a lead member is inserted and mounted based on a plurality of X-ray tomographic images of the inspection object acquired from a CT apparatus.

[0079] The lead region estimation unit 23 uses the three-dimensional data generated by the three-dimensional data generation unit 22 to estimate the lead region at a designated fault position in the weld. To perform this estimation, the lead region estimation unit 23 further includes a lead region extraction unit 231, a lead center of gravity calculation unit 232, and a lead area calculation unit 233.

[0080] Furthermore, the designated slice position can be determined based on a predetermined rule. For example, a fixed value for the distance of the three-dimensional data in the Z-axis direction can be predetermined, and the boundary position when the three-dimensional data is divided at each fixed value can be used as the designated slice position. Alternatively, the Z-axis distance L of the inspection region and a fixed parameter N can be used, and for each value obtained by dividing L by N, the boundary position when the three-dimensional data is divided can be used as the designated slice position.

[0081] Based on the three-dimensional data generated by the three-dimensional data generation unit 22, the lead region extraction unit 231 determines the positions of the leads protruding from each end of the solder-filled through-hole (i.e., the portions not covered by the solder), and extracts the lead regions from each horizontal slice image. The lead positions determined here can be based on information preset and stored in the storage unit 27, or can be specified by the user on a case-by-case basis.

[0082] Figure 4 、 Figure 5 An example of the region extracted by the lead region extraction unit 231 is shown. Figure 4 This is an explanatory diagram showing the relationship between a schematic cross-sectional view of the vicinity of a soldering portion of a component mounted on a substrate, three-dimensional data of the corresponding portion, and a vertical slice image generated based on the three-dimensional data. Figure 4 (A) is a schematic cross-sectional view showing the vicinity of the soldering portion of the substrate mounting component. Figure 4 (B) means Figure 4 (A) corresponds to the three-dimensional data of the part, Figure 4 (C) represents a vertical slice image generated based on the three-dimensional data. Figure 4 The lines T1 and T2 in FIG. 5 represent the fault positions determined by the lead region extraction unit 231 .

[0083] Figure 5 The horizontal slice image of the extracted lead portions T1 and T2 showing the determined slice positions is shown. The lead region extraction unit 231 determines the lead regions of the extracted lead portions T1 and T2 by binarizing the obtained horizontal slice image.

[0084] The lead center of gravity calculation unit 232 calculates the center of gravity of the lead at the specified slice position. The center of gravity of the lead at the specified slice position can be calculated by, for example, extracting the center of gravity of each lead region from the horizontal slice images of lead portions T1 and T2 and then using this center of gravity information and the equation of the line.

[0085] The lead area calculation unit 233 calculates the area of ​​the lead at the designated fault position. Here, the area of ​​the lead at the designated fault position can be calculated, for example, by adding to the lead area of ​​the extracted lead portion T1 a value obtained by subtracting the Z-axis coordinate value of the extracted lead portion T1 from the Z-axis coordinate value of the designated fault position, divided by a value obtained by subtracting the Z-axis coordinate value of the extracted lead portion T2 from the Z-axis coordinate value of the extracted lead portion T1, and multiplying the value obtained by subtracting the lead area of ​​the extracted lead portion T1 from the lead area of ​​the extracted lead portion T2.

[0086] The lead region estimation unit 23 estimates the lead region at the designated fault position based on the centroid position and area of ​​the lead at the designated fault position obtained as described above.

[0087] The gap region specifying unit 24 specifies the gap region of the designated fault position based on the three-dimensional data generated by the three-dimensional data generating unit 22 and the information on the lead region estimated by the lead region estimating unit 23 .

[0088] based on Figure 6 , the gap region determination process performed by the gap region determination unit 24 will be described. Figure 6 (A) shows a horizontal cross-sectional image showing a void candidate at a specified tomographic position. Figure 6 (B) shows the estimated lead region of the designated fault position estimated by the lead region estimation unit 23 . Figure 6 (C) shows a state where the estimated lead line region is overlapped with the gap candidate.

[0089] The gap region determination unit 24 first extracts gap candidates from the horizontal slice image at the designated slice position. Figure 6 As shown in (A), the gap and the lead cannot be identified in the X-ray image, and in this state, the gap region cannot be accurately determined. Therefore, a process is performed to mask the estimated lead region estimated by the lead region estimation unit 23 with the gap candidate ( Figure 6 Then, the region V remaining after the masking process is determined as a void region.

[0090] In addition, if Figure 6 As shown, the estimated shape of the lead area may be a shape flattened into a perfect circle or a square, or may be a shape obtained by extracting a horizontal slice image of the lead portions T1 and T2.

[0091] The quality determination unit 25 performs an inspection to determine the quality of the component-mounted substrate by comparing the parameters of the void area determined by the void area determination unit 24 with the inspection reference stored in the storage unit 27. For example, if the area of ​​the void determined by the void area determination unit 24 is less than a threshold void area, the product is determined to be good; otherwise, the product is determined to be defective.

[0092] The user confirmation image generating unit 26 generates a user confirmation image that shows at least a horizontal tomographic plane at a designated tomographic position in a state where the estimated lead region is masked by the gap candidate. Figure 7 An example of a user confirmation image is shown. The generated user confirmation image is displayed on the output unit 28 so that the user can visually confirm it.

[0093] (Flow of gap inspection process)

[0094] Next, refer to Figure 8The following describes the process for performing gap inspection on a component-mounted substrate, which is the inspection target, in this embodiment. First, under the control of the control unit 21, a CT device captures X-ray tomographic images of the substrate (S101). The three-dimensional data generator 22 then generates three-dimensional data of the substrate based on the multiple X-ray tomographic images (S102).

[0095] Next, the lead region extraction unit 231 determines the positions of the leads protruding from both ends of the solder-filled through-hole based on the three-dimensional data generated in step S102, and extracts the lead regions from each horizontal slice image (step S103). Next, the user sets the designated slice positions (S104). Alternatively, the designated slice positions can be automatically set based on user-defined rules. The following loop L1 is then executed for all designated slice positions.

[0096] In loop L1, a tomographic image at a designated slice position is first acquired from the three-dimensional data (S105). The lead region estimation unit 23 estimates the lead region at the designated slice position (S106). The gap region determination unit 24 then determines the gap region at the designated slice position (S107), completing the series of loop L1 processing.

[0097] When the processing of loop L1 is completed for all designated fault positions, the quality determination unit 25 performs a quality inspection of the component-mounted substrate (S108). Specifically, if the area of ​​the void region determined in step S107 is less than the threshold void area, the substrate is determined to be good; otherwise, it is determined to be defective.

[0098] Afterwards, the user confirmation image generation unit 26 generates a user confirmation image and displays it on the output unit 28 along with the determination result of step S108 ( S109 ), temporarily terminating the routine. Details of the processing in each step have been explained in the description of each functional unit and are therefore omitted.

[0099] The X-ray inspection system 1 described above can distinguish voids within solder, which are invisible from the outside, from leads and perform inspections accordingly. Furthermore, the user can view an image showing the lead area masked and the void area identified, along with the inspection results. Therefore, during X-ray inspections of component-mounted substrates, the validity of the inspection results can be easily determined, and inspection standards based on these results can be easily taught.

[0100] Modifications

[0101] Furthermore, in the first embodiment described above, the lead region estimation unit 23 calculates the area of ​​the lead region by the lead area calculation unit 233 to obtain the area of ​​the lead at the designated fault position. However, it is not always necessary to obtain the lead area in this manner.

[0102] Figure 9 This is a schematic block diagram showing the functional configuration of an X-ray inspection system 2 according to a modified example of Embodiment 1. The X-ray inspection system 2 of this modified example differs from the aforementioned X-ray inspection system 1 only in the function of calculating the area of ​​the lead wire region by the lead wire region estimation unit 30. The remaining configuration and functions are identical, and thus, the same reference numerals are used, and description thereof will be omitted.

[0103] The X-ray inspection system 2 of this modified example differs from the X-ray inspection system 1 in that the lead area estimation unit 30 includes a lead area determination unit 234 in place of the lead area calculation unit. Rather than calculating the lead area based on horizontal slice images of the extracted lead portion, lead area determination unit 234 obtains information related to the lead area from component specification information stored in storage unit 27. This configuration allows the lead area to be calculated based on information about the predetermined component dimensions, enabling accurate and efficient estimation of the lead area.

[0104] <Implementation Method 2>

[0105] Then, based on Figures 10 to 12 An X-ray inspection system 3 as another embodiment of the present invention will be described. Figure 10 This is a schematic block diagram showing the functional structure of the X-ray inspection system 3 of this embodiment. Figure 10 As shown, the X-ray inspection system 3 of this embodiment is different from the X-ray inspection system 1 in that it also has a functional unit of a void volume calculation unit 29. Since multiple structures and functions are the same, the same structures and functions are marked with the same figure numbers and detailed descriptions are omitted.

[0106] The void volume calculation unit 29 in the X-ray inspection system 3 calculates the volume of the void in the filled portion based on the horizontal slice images at the multiple designated slice positions where the void region has been identified by the void region identification unit 24. Specifically, for example, if the void regions at the multiple designated slice positions are considered to be the same void with respect to the Z-axis direction, the volume can be calculated by adding the areas of these void regions to obtain the sum of the areas of the void regions at each designated slice position. Alternatively, the void volume can be calculated by multiplying the sum of the areas of the void regions at each designated slice position by the Z-axis distance between the designated slice positions.

[0107] Furthermore, whether the gap regions at multiple designated fault positions are the same gap with respect to the Z-axis direction can be determined based on the distance between the centroids of the gap regions at the designated fault positions, the overlap pattern of the gap regions, and the like.

[0108] Next, refer to Figure 11 , the process of performing the gap inspection of the component mounting substrate as the inspection object in this embodiment will be described. Figure 11 As shown, the basic processing flow is the same as that of the X-ray inspection system 1, but the flow after step S107 of determining the gap area is different.

[0109] After step S107, the void volume calculation unit 29 calculates the void volume (step S201). Next, in step S202, a pass / fail determination is performed. Here, the inspection criterion is a void volume threshold. If the void volume calculated by the void volume calculation unit 29 is below the threshold, the product is determined to be passable; otherwise, it is determined to be defective. The user confirmation image generation unit 26 then generates a user confirmation image and displays it on the output unit 28 along with the determination result from step S202 (S203). This routine then terminates.

[0110] Figure 12 An example of a user confirmation image in this embodiment is shown. Figure 12 (A) is a diagram showing a horizontal tomographic image (ie, an XY cross-sectional image) at a specified tomographic position of a component mounting substrate. Figure 12 (B) is a diagram showing an XZ cross-sectional image of a region including a solder filling portion of a component mounting substrate. Figure 12 (C) is a diagram showing a YZ cross-sectional image of a region including a solder filling portion of the component mounting substrate.

[0111] like Figure 12 As shown, the user confirmation image in this embodiment also displays XZ and YZ cross-sectional images of the soldered portion. Within each image, which also includes the XY cross-sectional images, the gap area and lead area are superimposed within the solder area. Furthermore, the front boundary line U of the component mounting substrate, the designated fault position display line S, and the back boundary line D are also superimposed.

[0112] According to the X-ray inspection system 3 of the present embodiment described above, the state of the welded portion of the component mounting substrate can be three-dimensionally grasped, and user convenience can be further improved.

[0113] <Other>

[0114] The above-described embodiments are merely illustrative of the present invention and are not limited to the specific embodiments described above. Various modifications and combinations of the present invention are possible within the scope of its technical concept. For example, the modified example of the first embodiment described above can be combined with the second embodiment to form an X-ray inspection system that can determine the area of ​​the lead region using the lead area determination unit and three-dimensionally determine the void volume using the void volume calculation unit.

[0115] Furthermore, at least a portion of the storage unit in each of the above examples may be provided as a storage device separate from the information processing terminal, or may be connected to the cloud. Furthermore, in each of the above examples, the X-ray inspection system may be provided as an integrated device, i.e., a device in which the CT apparatus and the control console are integrated. Furthermore, in each of the above examples, the order of the processing in steps S103 and S104 may be reversed.

[0116] In each of the above examples, the output unit 28 may be caused to display images of the void candidate, the lead region, and the void region (after masking) for each designated slice position.

[0117] <Note>

[0118] One aspect of the present invention is an inspection system (1) for inspecting a component mounting substrate on which an electronic component having leads is insertedly mounted, the inspection system (1) comprising:

[0119] An X-ray generating unit (11) irradiates X-rays to the component mounting substrate;

[0120] An X-ray photographing unit (12) for photographing X-rays transmitted through the component mounting substrate;

[0121] a three-dimensional data generating unit (22) for generating three-dimensional data of a region including at least a soldering portion of an electronic component insertedly mounted on the component mounting substrate using information of a plurality of X-ray images captured by the X-ray capturing unit;

[0122] a lead area estimation unit (23; 30) that estimates a lead area at a predetermined horizontal slice position of a solder filling portion filled with solder in the soldering portion using the three-dimensional data; and

[0123] A void area determination unit (24) determines a void area at a predetermined horizontal fault position of the solder filling portion using the information estimated by the lead area estimation unit.

[0124] Another aspect of the present invention is a method for inspecting a component-mounted substrate on which an electronic component having leads is inserted and mounted, the method comprising:

[0125] An image acquisition step (S101) of acquiring a plurality of X-ray images obtained by photographing the component mounting substrate using X-rays;

[0126] a three-dimensional data generating step ( S102 ) of generating three-dimensional data of a region including at least a soldering portion of an electronic component insertedly mounted on the component mounting substrate using information from the plurality of X-ray images;

[0127] a lead region estimating step ( S106 ) of estimating a lead region at a predetermined horizontal slice position of a solder filling portion filled with solder in the soldering portion using the three-dimensional data; and

[0128] The void region determining step ( S107 ) determines a void region at a predetermined horizontal cross-section position of the solder filling portion using the information estimated in the lead region estimating step.

[0129] Description of labels

[0130] 1, 2, 3: X-ray inspection system; 9: X-ray inspection device; 11, 92: X-ray source; 12, 93: X-ray camera; 921, 931: X-table; 922, 932: Y-table; C1, C2: circular orbit; O: inspection object; T1, T2: extraction lead portion; V: gap area; U: front boundary line; D: back boundary line; S: designated fault position display line.

Claims

1. An inspection system for a component mounting substrate on which an electronic component having leads is insertedly mounted, the inspection system comprising: an X-ray generating unit that irradiates X-rays to the component mounting substrate; an X-ray imaging unit that captures X-rays that have passed through the component mounting substrate; a three-dimensional data generating unit that generates three-dimensional data of a region including at least a soldering portion of an electronic component insertedly mounted on the component mounting substrate using information from a plurality of X-ray images captured by the X-ray capturing unit; a lead region estimating unit that estimates a lead region at a predetermined horizontal cross-sectional position of a solder-filled portion filled with solder in a through-hole in the soldered portion using the three-dimensional data; as well as a void region determining unit that determines a void region at a predetermined horizontal cross-section position of the solder filling portion using the information estimated by the lead region estimating unit; The lead region estimation unit includes a lead center-of-gravity calculation unit that calculates the center-of-gravity position of the lead at a predetermined horizontal cross-sectional position of the solder-filled portion based on a plurality of horizontal cross-sectional images of the lead protruding from both ends of the through-hole filled with solder in the soldering portion. The lead region estimation unit estimates the lead region at a predetermined horizontal cross-section position of the solder filling portion using at least the information calculated by the lead gravity center calculation unit.

2. The inspection system according to claim 1, characterized in that The lead region estimation unit further includes a lead area calculation unit that calculates the area of ​​the lead at a predetermined horizontal cross-sectional position of the solder-filled portion based on a plurality of horizontal cross-sectional images of the lead protruding from both ends of the through-hole filled with solder in the soldered portion. The lead region estimation unit estimates the lead region at a predetermined horizontal cross-section position of the solder filled portion using at least the information calculated by the lead area calculation unit.

3. The inspection system according to claim 1, characterized in that The inspection system further includes a storage unit that stores at least information related to specifications of the electronic component. The lead area estimation unit also has a lead area determination unit, which determines the area of ​​the lead at the specified horizontal fault position of the solder filling part based on the information related to the specifications of the electronic component stored in the storage unit. The lead area estimation unit uses at least the information determined by the lead area determination unit to estimate the lead area at the specified horizontal fault position of the solder filling part.

4. The inspection system according to any one of claims 1 to 3, characterized in that The void region determining unit performs masking processing on the lead region estimated by the lead region estimating unit on the horizontal slice image indicating the predetermined horizontal slice position, thereby determining the void region at the predetermined horizontal slice position of the solder filling portion.

5. The inspection system according to claim 4, characterized in that The inspection system also has: a user confirmation image generating unit configured to generate a user confirmation image, the user confirmation image at least showing a state in which a masking process is performed on the estimated lead area for the horizontal tomographic image indicating the predetermined horizontal tomographic position; as well as An image display unit displays at least the user confirmation image.

6. The inspection system according to any one of claims 1 to 3, characterized in that: The inspection system further includes an inspection unit configured to determine whether the component mounting substrate is good or bad based on a parameter related to the gap region determined by the gap region determining unit.

7. The inspection system according to any one of claims 1 to 3, characterized in that: The inspection system further includes a void volume calculation unit that calculates the volume of the void in the solder filling portion based on a plurality of horizontal slice images showing different horizontal slice positions in the solder filling portion where the void region is determined by the void region determination unit.

8. The inspection system according to claim 7, characterized in that: The inspection system further includes an inspection unit configured to determine the quality of the component mounting substrate based on the volume of the void in the solder-filled portion calculated by the void volume calculation unit.

9. An information processing device for inspecting a component mounting substrate on which an electronic component having leads is insertedly mounted, the information processing device comprising: a three-dimensional data generating unit that acquires a plurality of X-ray images obtained by imaging the component mounting substrate using X-rays, and generates three-dimensional data of a region including at least a soldering portion of an electronic component inserted and mounted on the component mounting substrate using information from the plurality of X-ray images; a lead region estimating unit that estimates a lead region at a predetermined horizontal cross-sectional position of a solder-filled portion filled with solder in a through-hole in the soldered portion using the three-dimensional data; as well as a void region determining unit that determines a void region at a predetermined horizontal cross-section position of the solder filling portion using the information estimated by the lead region estimating unit; The lead region estimation unit includes a lead center-of-gravity calculation unit that calculates the center-of-gravity position of the lead at a predetermined horizontal cross-sectional position of the solder-filled portion based on a plurality of horizontal cross-sectional images of the lead protruding from both ends of the through-hole filled with solder in the soldering portion. The lead region estimation unit estimates the lead region at a predetermined horizontal cross-section position of the solder filling portion using at least the information calculated by the lead gravity center calculation unit.

10. An inspection method for a component mounting substrate on which an electronic component having leads is insertedly mounted, the inspection method comprising: an image acquisition step of acquiring a plurality of X-ray images obtained by photographing the component mounting substrate using X-rays; a three-dimensional data generating step of generating three-dimensional data of a region including at least a soldering portion of an electronic component insertedly mounted on the component mounting substrate using information from the plurality of X-ray images; a lead region estimating step of estimating a lead region at a predetermined horizontal slice position of a solder filling portion filled with solder in a through hole in the soldering portion using the three-dimensional data; and a void region determining step of determining a void region at a predetermined horizontal cross-section position of the solder filling portion using the information estimated in the lead region estimating step; In the lead area estimation step, based on multiple horizontal tomographic images of the lead protruding from both ends of the through-hole filled with solder in the welding portion, the center of gravity position of the lead at the specified horizontal tomographic position of the solder-filled portion is calculated, and the lead area at the specified horizontal tomographic position of the solder-filled portion is estimated using at least information on the center of gravity position of the lead. 11 . A storage medium that non-transitorily stores a program for causing an information processing terminal to execute each step of the inspection method according to claim 10 .

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