Substrate inspection system and substrate inspection method

Abstract

To provide a substrate inspection system and a substrate inspection method capable of accurately determining the quality of the shape of a solder ball.SOLUTION: The substrate inspection system 100 includes the X-ray imaging apparatus 10 configured to perform X-ray imaging of the substrate 200 on which the solder balls 210 are arranged, and the substrate inspection apparatus 20 including the inspection apparatus controller 21 configured to generate the X-ray image 300 of the substrate 200 imaged by the X-ray imaging apparatus 10, and the inspection apparatus controller 21 is configured to generate the determination image 310 based on the X-ray image 300 of the substrate 200 imaged by the X-ray imaging apparatus 10. The quality of the shape of the solder ball 210 is determined based on a plurality of distances di from the center of gravity G of the solder ball region 312 in the determination image 310 to the plurality of outer edge portions Ei.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a board inspection system and a board inspection method, and more particularly to a board inspection system and a board inspection method for generating an X-ray image of a board on which solder balls are arranged. [Background technology]

[0002] BACKGROUND ART Conventionally, an X-ray imaging system that generates an X-ray image of a substrate on which solder balls are arranged is known (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an X-ray imaging system including a fluoroscopic device that generates an X-ray image of a substrate on which solder balls are arranged, and an analysis device that analyzes the generated X-ray image. The X-ray imaging system described in the above-mentioned Patent Document 1 inspects for abnormalities such as the shape of the solder balls based on the generated X-ray image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-29975 Summary of the Invention [Problem to be solved by the invention]

[0005] Although not described in Patent Document 1, when inspecting the shape of solder balls in a conventional X-ray imaging system such as that described in Patent Document 1, a determination image may be generated from an X-ray image of a board on which solder balls are arranged, in which the board area and solder ball areas are binarized and displayed. In this case, the roundness of each of the multiple solder ball areas shown in the determination image is calculated based on the area, perimeter, etc. Then, based on the roundness values ​​of each of the multiple solder ball areas, it is determined whether the shapes of the multiple solder balls are good or bad.

[0006] However, in the above-described determination using circularity, even if a solder ball has a defective shape, including localized irregularities, for example, if the solder ball has both convex and concave portions, the area and perimeter may be close to those of a perfectly circular solder ball. In this case, the difference between the calculated circularity of the defective solder ball and the circularity of a good solder ball may be very small, or may not even appear. For this reason, it may not be possible to accurately determine the shape of a solder ball based on circularity. Therefore, there is a demand for a board inspection system and a board inspection method that can accurately determine the quality of a solder ball's shape.

[0007] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a board inspection system and a board inspection method that can accurately determine whether the shape of a solder ball is good or bad. [Means for solving the problem]

[0008] In order to achieve the above object, a substrate inspection system in a first aspect of the present invention comprises an X-ray imaging device that takes X-ray images of a substrate on which solder balls are arranged, and an inspection device including a control unit that generates an X-ray image of the substrate taken by the X-ray imaging device, and the control unit is configured to generate a judgment image based on the X-ray image of the substrate taken by the X-ray imaging device, and to judge whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball area in the judgment image to multiple outer edge portions.

[0009] In addition, in order to achieve the above-mentioned object, a substrate inspection method in a second aspect of the present invention includes an imaging process for taking X-ray images of a substrate on which solder balls are arranged, an X-ray image generation process for generating an X-ray image of the photographed substrate, a judgment image generation process for generating a judgment image based on the X-ray image, and a judgment process for judging whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball area in the judgment image to multiple outer edge portions. [Effects of the Invention]

[0010] In the circuit board inspection system according to the first aspect and the circuit board inspection method according to the second aspect, as described above, the control unit performs a determination step of determining whether the shape of the solder ball is acceptable based on multiple distances from the center of gravity of the solder ball region in the determination image to multiple outer edge portions. This allows the determination of the shape of the solder ball, even for solder balls that include localized irregularities that cannot be evaluated by circularity, by utilizing the difference in distance from the center of gravity between the localized irregularities and the circular portion. As a result, it is possible to provide a circuit board inspection system and a circuit board inspection method that can accurately determine the shape of the solder ball. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing the overall configuration of a substrate inspection system according to an embodiment of the present invention; [Figure 2] FIG. 2 illustrates a substrate on which solder balls are disposed according to an embodiment of the present invention. [Figure 3] 1A and 1B are diagrams for explaining an X-ray image generated in a substrate inspection system according to an embodiment of the present invention. [Figure 4] 10A and 10B are diagrams for explaining a determination image generated in the substrate inspection system according to the embodiment of the present invention. [Figure 5] 10A and 10B are diagrams illustrating a solder ball region having a good shape according to an embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating a solder ball region including a convex portion according to an embodiment of the present invention. [Figure 7] 10A and 10B are diagrams illustrating a solder ball region including a recessed portion according to an embodiment of the present invention. [Figure 8] 10A and 10B are diagrams for explaining a determination result using a determination image according to an embodiment of the present invention. [Figure 9]FIG. 4 is a flowchart illustrating an operation performed by a control unit according to an embodiment of the present invention. [Figure 10] 10A and 10B are diagrams illustrating a solder ball region including both convex and concave portions according to a modified example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] A substrate inspection system 100 according to this embodiment will be described with reference to FIGS.

[0014] (Overall configuration of the circuit board inspection system) 1, the substrate inspection system 100 includes an X-ray imaging device 10, a substrate inspection device 20, and a solder ball inference device 30. The substrate inspection system 100 is a system that inspects the shapes and the like of a plurality of solder balls 210 (bumps) (see FIG. 2) arranged on a substrate 200. The X-ray imaging device 10 and the solder ball inference device 30 are each connected to the substrate inspection device 20 so as to be able to communicate with each other.

[0015] 2, a plurality of solder balls 210 and an electronic component 220 are arranged on a substrate 200. The electronic component 220 is electrically connected to the substrate 200 by the plurality of solder balls 210. The plurality of solder balls 210 have substantially the same size. The plurality of solder balls 210 are arranged in a grid pattern on the substrate 200. That is, the electronic component 220 is connected to the substrate 200 by a BGA (Ball Grid Array). The electronic component 220 is, for example, a chip capacitor.

[0016] (Configuration of X-ray equipment) 1, the X-ray imaging device 10 is an apparatus for X-ray imaging of a substrate 200 on which a plurality of solder balls 210 (see FIG. 2) are arranged. The X-ray imaging device 10 includes an X-ray irradiation unit 11 and an X-ray detection unit 12.

[0017] The X-ray irradiator 11 is configured to irradiate X-rays. The X-ray irradiator 11 includes an X-ray tube that irradiates X-rays when power is supplied from a power supply device (not shown). The X-ray irradiator 11 irradiates X-rays onto a substrate 200 on which a plurality of solder balls 210 (see FIG. 2) are arranged.

[0018] The X-ray detection unit 12 detects the X-rays irradiated from the X-ray irradiation unit 11. The X-ray detection unit 12 outputs an electrical signal corresponding to the detected X-rays. The X-ray detection unit 12 is, for example, an FPD (Flat Panel Detector). The electrical signal output from the X-ray detection unit 12 is input to an inspection device control unit 21 (described later) of the substrate inspection device 20.

[0019] (Configuration of circuit board inspection device) 1, the substrate inspection device 20 is a device that inspects the shapes and the like of the solder balls 210 (see FIG. 2) arranged on the substrate 200, using an X-ray image 300 (see FIG. 3) of the substrate 200 on which a plurality of solder balls 210 are arranged, which is X-ray photographed by the X-ray imaging device 10. The substrate inspection device 20 includes an inspection device control unit 21, an inspection device storage unit 22, and a display unit 23.

[0020] The inspection device control unit 21 controls a power supply device (not shown) to control the irradiation of X-rays by the X-ray irradiation unit 11. The inspection device control unit 21 includes, for example, a processor such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an FPGA (Field-Programmable Gate Array) configured for image processing, and memories such as a ROM (Read Only Memory) or RAM (Random Access Memory). The inspection device control unit 21 is an example of a "control unit" in the claims.

[0021] The inspection device storage unit 22 stores various programs, various parameters, etc. executed by the inspection device control unit 21. The inspection device storage unit 22 includes a non-volatile memory such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The inspection device storage unit 22 stores a substrate inspection program 22a, which will be described later.

[0022] The display unit 23 is, for example, a liquid crystal display. The display unit 23 is controlled by the inspection device control unit 21 to display an image including text information, etc. The display unit 23 displays the determination result using the selected determination image 310 (see FIG. 4).

[0023] (Configuration of solder ball inference device) 1, the solder ball inference device 30 is a device that infers a portion that is a solder ball region 312 (see FIG. 3) in an X-ray image 300. The solder ball inference device 30 includes an inference device control unit 31 and an inference device storage unit 32.

[0024] The inference device control unit 31 includes, for example, a processor such as a CPU, a GPU, or an FPGA configured for image processing, and memories such as a ROM, a RAM, etc. The inference device control unit 31 uses a trained model 32a (described later) stored in the inference device storage unit 32 to generate a probability image (inference image) indicating the probability of a portion of an X-ray image 300 (see FIG. 3) input from the inspection device control unit 21 of the board inspection device 20 being a solder ball region 312 (see FIG. 3).

[0025] The inference device storage unit 32 stores various programs executed by the inference device control unit 31, various parameters, etc. The inference device storage unit 32 includes, for example, a non-volatile memory such as an HDD or SSD. The inference device storage unit 32 stores a trained model 32a that has been trained in advance by machine learning using a large amount of data set of the X-ray image 300 for the portion that is the solder ball region 312 (see FIG. 3) in the X-ray image 300 (see FIG. 3).

[0026] (Configuration of the control unit of the substrate inspection device) As shown in FIG. 1, the inspection device control unit 21 includes, as functional blocks, an X-ray image generation unit 21a, a determination image generation unit 21b, an index value calculation unit 21c, a determination unit 21d, a concavo-convex result calculation unit 21e, and a display control unit 21f. The X-ray image generation unit 21a, the determination image generation unit 21b, the index value calculation unit 21c, the determination unit 21d, the concavo-convex result calculation unit 21e, and the display control unit 21f are software-configured as functional blocks realized by the inspection device control unit 21 executing the substrate inspection program 22a stored in the inspection device storage unit 22. That is, the substrate inspection program 22a causes a computer (inspection device control unit 21) to execute the control performed by the X-ray image generation unit 21a, the determination image generation unit 21b, the index value calculation unit 21c, the determination unit 21d, the concavo-convex result calculation unit 21e, and the display control unit 21f.

[0027] <X-ray image generation unit> The X-ray image generation unit 21a (see FIG. 1) generates an X-ray image 300 of the substrate 200 (see FIG. 1) taken by X-ray as shown in FIG. 3. Specifically, as shown in FIG. 1, the X-ray image generation unit 21a generates the X-ray image 300 based on the electrical signal output from the X-ray detection unit 12 of the X-ray imaging device 10. The X-ray image 300 includes a substrate portion 301 on which the substrate 200 (see FIG. 1) is imaged and a solder ball portion 302 on which the solder balls 210 (see FIG. 1) are imaged.

[0028] <Determination image generation unit> As shown in FIG. 4, the determination image generating unit 21b (see FIG. 1) generates a determination image 310 by extracting a solder ball region 312 from an X-ray image 300. Specifically, as shown in FIG. 1, the determination image generating unit 21b inputs the X-ray image 300 (see FIG. 3) to the inference device control unit 31 of the solder ball inference device 30. The inference device control unit 31 of the solder ball inference device 30 uses a trained model 32a stored in the inference device storage unit 32 of the solder ball inference device 30 to generate an inference image (not shown) that indicates the probability that a portion of the X-ray image 300 input from the inspection device control unit 21 of the board inspection device 20 is a solder ball 210 (see FIG. 1). The inference device control unit 31 of the solder ball inference device 30 outputs the generated inference image to the inspection device control unit 21 of the board inspection device 20. The determination image generating unit 21b binarizes the inference image output from the inference device control unit 31 of the solder ball inference device 30, thereby generating a determination image 310 as shown in FIG.

[0029] 4, determination image 310 includes substrate region 311, which indicates the portion where substrate 200 (see FIG. 1) exists, and solder ball region 312, which indicates the portion where solder ball 210 (see FIG. 1) exists. In this case, the multiple solder ball regions 312 included in determination image 310 may be a mixture of good-shaped regions that are close to a perfect circle and defective regions that include localized irregularities. For example, solder ball region 312a has a good shape that is close to a perfect circle, solder ball region 312b has a defective shape that includes a convex portion, and solder ball region 312c has a defective shape that includes a concave portion.

[0030] <Index value calculation section> The index value calculation unit 21c calculates an index value V for the captured region at once, based on the X-ray image 300 and the determination image 310, for determining whether each of the multiple solder balls 210 on the substrate 200 has a good shape or a bad shape. Here, the calculation of the index value V performed by the index value calculation unit 21c will be specifically described using FIG. 5, which shows an enlarged view of a good-shape solder ball region 312a as one solder ball region 312 in the determination image 310. Note that in FIG. 5, for convenience of illustration, the ratio of the pixel size to the solder ball region 312 is exaggerated compared to the actual ratio.

[0031] The index value calculation unit 21c calculates the average radius R of the solder ball region 312a. ave Calculate the average radius R ave is a radius that is calculated pseudo-wise assuming that the solder ball region 312 is circular, even if it is not actually circular. The index value calculation unit 21c calculates the area S of the solder ball region 312a based on the number of pixels that make up the solder ball region 312a and the area of ​​the pixels (pixels) per unit that has been acquired in advance. The index value calculation unit 21c calculates the average radius R of the solder ball region 312a by dividing the calculated area S by the ratio of the circumference of the circle to its circumference π and then taking the square root. ave That is, the average radius R calculated by the index value calculation unit 21c is calculated. ave is expressed by the following formula:

number

[0032] Furthermore, the index value calculation unit 21c obtains the center of gravity G of the solder ball region 312a. For example, the index value calculation unit 21c acquires the coordinates of each pixel that constitutes the solder ball region 312a when a point at the top left of the determination image 310 (see FIG. 4) is set as a reference with coordinates (0, 0). At this time, the index value calculation unit 21c calculates the average value of the x coordinate and the average value of the y coordinate of each pixel that constitutes the solder ball region 312a, and sets the calculated coordinates as the center of gravity G. In this embodiment, the coordinates of the center of gravity G are set as (x g , y g ) is explained as follows.

[0033] The index value calculation unit 21c also calculates a plurality of distances di from the center of gravity G of the solder ball region 312a to a plurality of outer edge portions Ei. The outer edge portions Ei of the solder ball region 312a are the coordinates of pixels in the solder ball region 312a that are adjacent to the board region 311 and are distinguished by binarization, and are represented by E1, E2,...E n In this embodiment, the coordinates of the outer edge portion Ei are expressed as (x i , y i The distance di is calculated based on the following formula, for each of the coordinates of the outer edge portion Ei.

number

[0034] In addition, the index value calculation unit 21c calculates the average radius R ave and the distances di from the center of gravity G of the solder ball region 312a to the multiple outer edge portions Ei, one index value V is calculated. The index value V is a value used to determine the quality of the solder ball region 312, which will be described later, and is calculated based on the following mean square error formula. In this embodiment, the calculated index value V of the solder ball region 312a is set to 0.18.

number

[0035] Here, the index value calculation unit 21c calculates the index value V for the photographed region at once, and therefore similarly calculates the index value V for, for example, the solder ball region 312b shown in Figures 4 and 6 and the solder ball region 312c shown in Figures 4 and 7. Note that in Figures 6 and 7, for convenience of illustration, the ratio of the pixel size to the solder ball region 312 is shown exaggerated compared to the actual ratio.

[0036] 6, the solder ball region 312b including the convex portion has the same distance di as the solder ball region 312a (see FIG. 5) in most parts, but the distance di is larger in the convex portion. Also, since the number of pixels constituting the solder ball region 312b including the convex portion is greater than the number of pixels constituting the solder ball region 312a with a good shape, the average radius R ave In other words, the part used to calculate the index value V, (R ave -d i ) is slightly larger overall, and is extremely large in the convex portions. Therefore, the calculated index value V of the solder ball region 312b is larger than the index value V of the solder ball region 312a. In this embodiment, the calculated index value V of the solder ball region 312b is set to 4.65.

[0037] 7, the solder ball region 312c including the concave portion has a distance di similar to that of the solder ball region 312a (see FIG. 5) in most parts, but the distance di is smaller in the concave portion. Also, since the number of pixels constituting the solder ball region 312c including the concave portion is smaller than the number of pixels constituting the well-shaped solder ball region 312a, the average radius R ave In other words, the part used to calculate the index value V, (R ave -d i ) is large overall, and is extremely large in the concave portions. Therefore, the calculated index value V of the solder ball region 312c is larger than the index value V of the solder ball region 312a. In this embodiment, the calculated index value V of the solder ball region 312c is set to 5.17.

[0038] <Judgment part> The determination unit 21d (see FIG. 1) determines whether each solder ball region 312 in the determination image 310 has a good shape or a bad shape based on the index value V calculated by the index value calculation unit 21c and a threshold value set in advance by an operator or the like. For example, if the threshold value is set in advance to "3.0" by an operator or the like, the determination unit 21d determines that the solder ball regions 312 in the determination image 310 whose calculated index value V is 3.0 or less have a good shape, and determines that the solder ball regions 312 whose calculated index value V is greater than 3.0 have a bad shape. Therefore, the solder ball region 312a, which has a nearly perfect circle shape and an index value V of 0.18, is determined to have a good shape, while the solder ball region 312b, which has an index value V of 4.65 and includes a convex portion, and the solder ball region 312c, which has an index value V of 5.17 and includes a concave portion, are determined to have a bad shape. The determination is performed for one determination image 310 at a time.

[0039] <Unevenness result calculation section> The unevenness result calculation unit 21e (see FIG. 1) calculates the result as to whether the solder ball region 312 determined to have a defective shape by the determination unit 21d includes a convex portion or a concave portion. Specifically, the unevenness result calculation unit 21e calculates the result as to whether the solder ball region 312 includes a convex portion or a concave portion, among the portions used by the index value calculation unit 21c to calculate the index value V. ave -d i ) is a positive value and a negative value. Then, unevenness result calculation unit 21e calculates the result that the solder ball region 312 includes a convex portion when there are more conditions that result in a positive value than conditions that result in a negative value, and that the solder ball region 312 includes a concave portion when there are more conditions that result in a negative value than conditions that result in a positive value.

[0040] For example, in the solder ball region 312b shown in FIG. ave -d i ) is a positive value in 19 conditions and a negative value in 3 conditions. Therefore, the result is calculated that the solder ball region 312b includes a convex portion. In addition, in the solder ball region 312c shown in FIG. 7, ave -d i) has a positive value in three conditions and a negative value in 17 conditions, the result is calculated that solder ball region 312c includes a concave portion.

[0041] <Display control section> The display control unit 21f (see FIG. 1) displays the results of the determination by the determination unit 21d and the results calculated by the unevenness result calculation unit 21e on the display unit 23. For example, as shown in FIG. 8, the display control unit 21f highlights and displays the solder ball regions 312 determined to have a defective shape by the determination unit 21d, for example by surrounding the periphery with a thick line. Furthermore, the display control unit 21f may, for example, use different colors for the solder ball regions 312b including convex portions and the solder ball regions 312c including concave portions, so that they can be distinguished on the display unit 23.

[0042] [Board inspection method] Next, the substrate inspection method according to this embodiment will be described with reference to the flowchart shown in FIG.

[0043] 9, first, an X-ray image generating process is performed in step S1 to generate an X-ray image 300. In step S1, an X-ray image 300 (see FIG. 3) of a substrate 200 on which solder balls 210 (see FIG. 2) are arranged is generated by X-ray imaging using an X-ray imaging device 10 (see FIG. 1). Note that step S1 is performed by an X-ray image generating unit 21a of an inspection device control unit 21 of a substrate inspection device 20 (see FIG. 1).

[0044] Next, as shown in Fig. 9, a determination image generating process is performed in step S2 to generate a determination image 310. In step S2, as shown in Fig. 3, a determination image 310 is generated by extracting a solder ball region 312 from an X-ray image 300 of a board 200 on which solder balls 210 (see Fig. 2) are arranged. Note that step S2 is performed by the determination image generating unit 21b of the inspection device control unit 21 of the board inspection device 20 (see Fig. 1).

[0045] 9, the index value calculation process of step S3 is performed to calculate the index value V. In step S3, the average radius R of the plurality of solder ball regions 312 is calculated based on the determination image 310. ave and the distance di from the center of gravity G to the outer edge portion Ei, an index value V is calculated for each of the plurality of solder ball regions 312. Note that this step S3 is performed by the index value calculation unit 21c of the inspection device control unit 21 of the board inspection device 20 (see FIG. 1).

[0046] Next, as shown in FIG. 9, a determination process of step S4 is performed to determine whether each of the solder ball regions 312 has a good shape or a defective shape. In step S4, based on the index value V for each of the plurality of solder ball regions 312, it is confirmed whether each of the plurality of solder ball regions 312 is equal to or less than a threshold value, and a solder ball region 312 having an index value V greater than the threshold value is determined to have a defective shape. That is, a solder ball 210 (see FIG. 2) corresponding to a solder ball region 312 determined to have a defective shape in the determination image 310 is determined to have a defective shape. At this time, a board 200 on which a solder ball 210 with a defective shape is arranged may be determined to be a defective product. Note that step S4 is performed by the determination unit 21d of the inspection device control unit 21 of the board inspection device 20 (see FIG. 1).

[0047] 9, the unevenness result calculation process of step S5 is performed to calculate the unevenness result. In step S5, for the solder ball region 312 in the determination image 310 that was determined to have a defective shape in step S4, the part of the portion used to calculate the index value V (R ave -d i ) is a positive value and a negative value. Then, depending on the number of conditions where the value is a positive value and the number of conditions where the value is a negative value, an unevenness result is calculated as to whether the solder ball region 312 has a convex portion or a concave portion. Note that this step S5 is performed by the unevenness result calculation unit 21e of the inspection device control unit 21 of the board inspection device 20 (see FIG. 1).

[0048] Next, as shown in Fig. 9, a display process of step S6 is performed in which the inspection results are displayed on the display unit 23. In step S6, the results determined or calculated in steps S4 and S5 are displayed in an identifiable manner on the display unit 23. Note that step S5 is performed by the display control unit 21f of the inspection device control unit 21 of the substrate inspection device 20 (see Fig. 1). By performing the above process, the inspection of the substrate 200 is completed.

[0049] [Effects of this embodiment] In this embodiment, the following effects can be obtained.

[0050] (Effects of the PCB inspection system) As described above, the substrate inspection system 100 of this embodiment is configured such that the inspection apparatus control unit 21 generates a determination image 310 based on the X-ray image 300 of the substrate 200 captured by the X-ray imaging apparatus 10, and determines whether the shape of the solder ball 210 is good or bad based on multiple distances di from the center of gravity G of the solder ball region 312 to multiple outer edge portions Ei in the determination image 310. This makes it possible to determine whether the shape of the solder ball 210 is good or bad, even for a solder ball 210 that includes a locally uneven shape that cannot be evaluated by circularity, by utilizing the fact that the distance di from the center of gravity G is different between the locally uneven shape and the circular portion. As a result, the shape of the solder ball 210 can be determined with high accuracy.

[0051] Furthermore, the substrate inspection system 100 of this embodiment has the following configuration, which provides further advantages.

[0052] That is, as described above, in the substrate inspection system 100 of this embodiment, the inspection device control unit 21 is configured to calculate an index value V for determining whether the shape of the solder ball 210 is good or bad, based on the distance di from the center of gravity G of the solder ball region 312 to the outer edge portion Ei in the determination image 310. As a result, compared to a case where the quality of the solder ball 210 is determined by checking all of the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei in the determination image 310, the quality of the solder ball 210 can be determined based only on the calculated index value V, making it easier to determine whether the solder ball 210 is good or bad.

[0053] In addition, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 calculates the average radius R based on the area S of the solder ball region 312 in the determination image 310. ave and the difference between the distances di from the center of gravity G to the outer edge portions Ei of the solder ball region 312. As a result, the radius directly derived as the distances di from the center of gravity G to the outer edge portions Ei is calculated as the average radius R of the solder balls 210. ave Therefore, when the solder ball 210 includes a portion with a locally uneven shape, the degree of unevenness of that portion can be reflected in the index value V. As a result, it is possible to more accurately determine whether the shape of the solder ball 210 is good or bad.

[0054] In the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 calculates the average radius R calculated based on the area S of the solder ball region 312 in the determination image 310. ave and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, is calculated as an index value V. As a result, the average radius R of the solder ball 210 is calculated as aveand the multiple distances di from the center of gravity G to the multiple outer edge portions Ei are squared, and an index value V is calculated that emphasizes the error. As a result, the quality of the shape of the solder ball 210 can be determined with even greater accuracy using the index value V in which the error is emphasized.

[0055] Furthermore, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 calculates the area S of the solder ball region 312 based on the area and number of pixels included in the solder ball region 312 in the determination image 310, and also calculates the average radius R of the solder ball region 312 based on the calculated area S of the solder ball region 312 and the ratio π. ave The calculated average radius R of the solder ball region 312 is calculated. ave and the difference between the distances di from the center of gravity G of the solder ball region 312 to the outer edge portions Ei of the solder ball region 312. As a result, the average radius R is calculated from the area S of the solder ball region 312 calculated based on the area and number of pixels included in the solder ball region 312 in the determination image 310. ave is calculated, so that even if the solder ball 210 includes a locally uneven shape, the radius of the solder ball region 312 can be determined in a pseudo manner by regarding the solder ball 210 as having a circular shape.

[0056] Furthermore, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 is configured to determine that the shape of the solder ball 210 is good when the index value V is equal to or less than a predetermined threshold value, and to determine that the shape of the solder ball 210 is defective when the index value V is greater than the predetermined threshold value. This makes it possible to easily determine whether the shape of the solder ball 210 is good or bad based on a simple comparison of whether the index value V is equal to or less than the predetermined threshold value or whether the index value V is greater than the predetermined threshold value.

[0057] Furthermore, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 calculates the average radius R of the solder ball region 312 in the judgment image 310. aveand the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei of the solder ball region 312. This makes it possible to distinguish between the protrusions and recesses of the solder balls 210, so that, for example, only the substrate 200 on which the solder balls 210 having protrusions are arranged can be treated as defective.

[0058] Furthermore, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 calculates the average radius R of the solder ball region 312 in the judgment image 310. ave and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, if the number of conditions for which the difference is a negative value is greater than the number of conditions for which it is a positive value, the result that the solder ball 210 has a concave portion is output, and if the number of conditions for which it is a positive value is greater than the number of conditions for which it is a negative value, the result that the solder ball 210 has a convex portion is output. ave Depending on the positive or negative difference between the distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei and the distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, it is possible to easily obtain a result as to whether the solder ball 210 has a concave portion or a convex portion.

[0059] Furthermore, in the substrate inspection system 100 of this embodiment, as described above, the inspection device control unit 21 is configured to cause the display unit 23 to display whether the solder balls 210 shown in the determination image 310 have a good shape or a defective shape in a manner that enables the operator or the like to visually easily grasp which of the solder balls 210 arranged on the substrate 200 have a defective shape.

[0060] (Effects of the circuit board inspection method) As described above, the substrate inspection method of this embodiment includes an imaging step of X-ray imaging the substrate 200 on which the solder balls 210 are arranged, step S1 as an X-ray image generation step of generating the X-ray image 300 of the captured substrate 200, step S2 as a determination image generation step of generating the determination image 310 based on the X-ray image 300, and step S4 as a judgment step of judging the acceptability of the shape of the solder ball 210 based on multiple distances di from the center of gravity G of the solder ball region 312 to multiple outer edge portions Ei in the determination image 310. As a result, even in the case of a solder ball 210 that includes a locally uneven shape that cannot be evaluated by circularity, the acceptability of the shape of the solder ball 210 can be judged by utilizing the fact that the distance di from the center of gravity G is different between the locally uneven shape portion and the circular portion. As a result, a substrate inspection method that can accurately judge the acceptability of the shape of the solder ball 210 can be provided.

[0061] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0062] For example, in the above embodiment, an example was shown in which the inspection apparatus control unit 21 is configured to calculate the index value V for determining whether the shape of the solder ball 210 is good or bad, based on the distance di from the center of gravity G to the outer edge portion Ei of the solder ball region 312 in the determination image 310, but the present invention is not limited to this. In the present invention, the distance di from the center of gravity G to the outer edge portion Ei of the solder ball region 312 in the determination image 310 may be used directly for determination, without newly calculating the index value V. In this case, for example, a solder ball 210 corresponding to a solder ball region 312 that includes a distance di equal to or greater than a predetermined distance threshold may be determined to have a defective shape.

[0063] In the above embodiment, the inspection device control unit 21 calculates the average radius R based on the area S of the solder ball region 312 in the determination image 310. ave and the distances di from the center of gravity G of the solder ball region 312 to the outer edge portions Ei of the solder ball region 312, but the present invention is not limited to this. ave , or a preset average radius R ave The index value V may be calculated using the above.

[0064] In the above embodiment, the inspection device control unit 21 calculates the average radius R based on the area S of the solder ball region 312 in the determination image 310. ave In the above example, the mean square error between the distances di from the center of gravity G of the solder ball region 312 to the outer edge portions Ei is calculated as the index value V, but the present invention is not limited to this. In the present invention, for example, the mean square error between the distances di from the center of gravity G of the solder ball region 312 to the outer edge portions Ei is calculated as the index value V. ave and the plurality of distances di from the center of gravity G of the solder ball region 312 to the plurality of outer edge portions Ei, may be directly set as the index value V.

[0065] In the above embodiment, the inspection device control unit 21 calculates the area S of the solder ball region 312 based on the area and number of pixels included in the solder ball region 312 in the determination image 310, and also calculates the average radius R of the solder ball region 312 based on the calculated area S of the solder ball region 312 and the ratio π. ave The calculated average radius R of the solder ball region 312 is calculated. ave and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, but the present invention is not limited to this. In the present invention, for example, the area S of the solder ball region 312 calculated based on the volume and weight of the solder ball 210, or the average radius R using a preset area, etc. aveand calculate the index value V.

[0066] In the above embodiment, the inspection device control unit 21 is configured to determine that the shape of the solder ball 210 is good when the index value V is equal to or less than a predetermined threshold value of 3.0, and to determine that the shape of the solder ball 210 is defective when the index value V is greater than the predetermined threshold value of 3.0. However, the present invention is not limited to this. In the present invention, the predetermined threshold value may be changed to an arbitrary value by an operator or the like. Alternatively, the shape of the solder ball 210 may be determined to be good when the index value V is less than a predetermined threshold value, and may be determined to be defective when the index value V is equal to or greater than the predetermined threshold value.

[0067] In the above embodiment, the inspection device control unit 21 determines the average radius R of the solder ball region 312 in the determination image 310. ave and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, the result of whether the solder ball 210 has a convex portion or a concave portion is calculated based on the difference between the distances di and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, but the present invention is not limited to this. In the present invention, the determination of the acceptability of the shape of the solder ball 210 may be completed without calculating the result of whether the solder ball 210 has a convex portion or a concave portion. In that case, step S5 is omitted in the flow diagram of FIG.

[0068] Furthermore, in the above embodiment, an example was shown in which the inspection device control unit 21 determined that the shape of the solder ball region 312 including either a convex portion or a concave portion is a defective shape, but the present invention is not limited to this. In the present invention, the inspection device control unit 21 can determine that the shape of the solder ball region 312 is a defective shape even if the solder ball region 312 has a shape that includes both a convex portion and a concave portion, as shown in Fig. 10. In this case, the distance di and the average radius R ave Because of the large difference between the ave -d i )2 Since the absolute value of the value becomes larger, the index value V for the solder ball region 312 shown in FIG. 10 becomes larger than the index value V for the solder ball region 312 with a good shape.

[0069] In the above embodiment, the inspection device control unit 21 determines the average radius R of the solder ball region 312 in the determination image 310. ave and the multiple distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei of the solder ball region 312, if the number of conditions for which the difference is a negative value exceeds the number of conditions for which the difference is a positive value, a result that the solder ball 210 has a concave portion is output, and if the number of conditions for which the difference is a positive value exceeds the number of conditions for which the difference is a negative value, a result that the solder ball 210 has a convex portion is output, but the present invention is not limited to this. ave and the maximum or minimum value of the difference between the distances di from the center of gravity G of the solder ball region 312 to the multiple outer edge portions Ei, the result of whether the solder ball 210 has a convex portion or a concave portion may be calculated.

[0070] Furthermore, in the above embodiment, an example was shown in which inspection device control unit 21 is configured to cause display unit 23 to display whether solder ball 210 shown in determination image 310 has a good shape or a defective shape in a manner that allows discrimination, but the present invention is not limited to this. In the present invention, for example, a display unit provided separately from board inspection device 20 may display whether solder ball 210 shown in determination image 310 has a good shape or a defective shape in a manner that allows discrimination.

[0071] In the above embodiment, an example has been shown in which the board inspection system 100 includes the solder ball inference device 30, but the present invention is not limited to this. In the present invention, the board inspection system 100 does not have to include the solder ball inference device 30. In that case, the solder ball inference device 30 may be provided separately from the board inspection system 100.

[0072] In the above embodiment, an example was shown in which the substrate inspection system 100 inspects the shapes of a plurality of solder balls 210 that are approximately the same size, but the present invention is not limited to this. In the present invention, the substrate inspection system 100 may also inspect the shapes of a plurality of solder balls 210 that are different sizes.

[0073] Furthermore, in the above embodiment, an example has been shown in which the substrate inspection system 100 inspects the shapes of a plurality of solder balls 210 arranged on the substrate 200 at once, but the present invention is not limited to this. In the present invention, the substrate inspection system 100 may inspect the shapes of the solder balls 210 arranged on the substrate 200 one by one.

[0074] Furthermore, in the above embodiment, an example was shown in which the inspection device control unit 21 displayed solder ball regions having a defective shape on the display unit 23, highlighting them with a thick line, but the present invention is not limited to this. In the present invention, the solder ball regions 312 may be displayed in any manner as long as it is possible to distinguish between good and defective shapes. For example, the index value V of each solder ball region 312 may be displayed separately from the diagram, superimposed on the solder ball region 312, or may be displayed as a table separately from the image. Furthermore, the completion of inspection of the board 200 on which a solder ball 210 with a defective shape has been arranged may be notified by sound.

[0075] Furthermore, in the above embodiment, an example was shown in which the inference device control unit 31 of the solder ball inference device 30 uses the trained model 32a stored in the inference device storage unit 32 of the solder ball inference device 30 to generate an inferred image indicating the probability of a portion that is a solder ball region 312 in the X-ray image 300 input from the inspection device control unit 21 of the board inspection device 20, but the present invention is not limited to this. In the present invention, the inspection device control unit 21 of the board inspection device 20 may use the trained model stored in the inspection device storage unit 22 of the board inspection device 20 to generate an inferred image indicating the probability of a portion that is a solder ball region 312 in the X-ray image 300.

[0076] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0077] (Item 1) an X-ray imaging device for X-raying the substrate on which the solder balls are arranged; an inspection device including a control unit that generates an X-ray image of the substrate photographed by the X-ray imaging device, The control unit is configured to generate a determination image based on the X-ray image of the board taken by the X-ray imaging device, and to determine whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball area in the determination image to multiple outer edge portions.

[0078] (Item 2) The control unit is configured to calculate an index value for determining whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball area in the determination image to multiple outer edge portions.

[0079] (Item 3) The control unit is configured to calculate the index value based on the difference between an average radius calculated based on the area of ​​the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

[0080] (Item 4) Item 4. The circuit board inspection system according to item 3, wherein the control unit is configured to calculate, as the index value, the mean square error between an average radius calculated based on the area of ​​the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

[0081] (Item 5) The control unit is configured to calculate the area of ​​the solder ball region based on the area and number of pixels included in the solder ball region in the determination image, calculate the average radius of the solder ball region based on the calculated area of ​​the solder ball region and pi, and calculate the index value based on the difference between the calculated average radius of the solder ball region and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

[0082] (Item 6) 3. The substrate inspection system according to claim 2, wherein the control unit is configured to determine that the shape of the solder ball is good when the index value is equal to or less than a predetermined threshold value, and to determine that the shape of the solder ball is bad when the index value is greater than the predetermined threshold value.

[0083] (Item 7) The control unit is configured to calculate a result as to whether the solder ball has a convex portion or a concave portion based on the difference between the average radius of the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

[0084] (Item 8) Item 8. The circuit board inspection system of item 7, wherein the control unit is configured to output a result that the solder ball has a concave portion when the difference between the average radius of the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions is a negative value more often than a positive value, and to output a result that the solder ball has a convex portion when the difference is a positive value more often than a negative value.

[0085] (Item 9) The inspection device further includes a display unit, Item 1. The substrate inspection system according to item 1, wherein the control unit is configured to cause the display unit to display whether the solder ball region shown in the judgment image has a good shape or a bad shape in an identifiable manner.

[0086] (Item 10) an imaging step of taking an X-ray image of the substrate on which the solder balls are arranged; an X-ray image generation step of generating an X-ray image of the photographed substrate; a determination image generating step of generating a determination image based on the X-ray image; and a determination step of determining whether the shape of the solder ball is good or bad based on a plurality of distances from the center of gravity of the solder ball region in the determination image to a plurality of outer edge portions. [Explanation of symbols]

[0087] 10 X-ray equipment 20 Circuit board inspection equipment 21 Inspection device control section 30 Solder ball inference device 100 PCB Inspection System 200 boards 210 solder balls 300 X-ray images 310 Judgment Image 311 Board area 312 Solder Ball Area di Distance from the center of gravity of the solder ball area to the outer edge Ei Outer edge of solder ball area G Center of gravity of solder ball area

Claims

1. an X-ray imaging device for X-raying a substrate on which solder balls are arranged; an inspection device including a control unit that generates an X-ray image of the substrate photographed by the X-ray imaging device, The control unit is configured to generate a determination image based on the X-ray image of the board taken by the X-ray imaging device, and to determine whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball area in the determination image to multiple outer edge portions.

2. 2. The substrate inspection system according to claim 1, wherein the control unit is configured to calculate an index value for determining whether the shape of the solder ball is good or bad based on multiple distances from the center of gravity of the solder ball region in the determination image to multiple outer edge portions.

3. 3. The substrate inspection system according to claim 2, wherein the control unit is configured to calculate the index value based on the difference between an average radius calculated based on the area of ​​the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

4. 4. The circuit board inspection system according to claim 3, wherein the control unit is configured to calculate, as the index value, a mean square error between an average radius calculated based on an area of ​​the solder ball region in the determination image and a plurality of distances from the center of gravity of the solder ball region to a plurality of outer edge portions.

5. 4. The circuit board inspection system of claim 3, wherein the control unit is configured to calculate the area of ​​the solder ball region based on the area and number of pixels included in the solder ball region in the determination image, calculate the average radius of the solder ball region based on the calculated area of ​​the solder ball region and pi, and calculate the index value based on the difference between the calculated average radius of the solder ball region and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions.

6. 3. The substrate inspection system according to claim 2, wherein the control unit is configured to determine that the shape of the solder ball is good when the index value is equal to or less than a predetermined threshold value, and to determine that the shape of the solder ball is bad when the index value is greater than the predetermined threshold value.

7. 2. The substrate inspection system according to claim 1, wherein the control unit is configured to calculate a result as to whether the solder ball has a convex portion or a concave portion based on the difference between the average radius of the solder ball region in the determination image and a plurality of distances from the center of gravity of the solder ball region to a plurality of outer edge portions.

8. 8. The circuit board inspection system according to claim 7, wherein the control unit is configured to output a result that the solder ball has a concave portion when the difference between the average radius of the solder ball region in the determination image and multiple distances from the center of gravity of the solder ball region to multiple outer edge portions is a negative value more often than a positive value, and to output a result that the solder ball has a convex portion when the difference is a positive value more often than a negative value.

9. The inspection device further includes a display unit, 2. The substrate inspection system according to claim 1, wherein the control unit is configured to cause the display unit to identifiably display whether the solder ball region shown in the judgment image has a good shape or a bad shape.

10. an imaging step of taking an X-ray image of the substrate on which the solder balls are arranged; an X-ray image generating step of generating an X-ray image of the photographed substrate; a determination image generating step of generating a determination image based on the X-ray image; and a determination step of determining whether the shape of the solder ball is good or bad based on a plurality of distances from the center of gravity of the solder ball region in the determination image to a plurality of outer edge portions.

Images