JP4610590B2 - X-ray inspection apparatus, X-ray inspection method, and X-ray inspection program - Google Patents

Description

  The present invention relates to an X-ray inspection apparatus, an X-ray inspection method, and an X-ray inspection program.

Conventionally, X-ray images are taken by detectors that are irradiated with X-rays and arranged at different positions, and the three-dimensional structure of the inspection target product is reconstructed to determine whether the inspection target product is good or bad. Has been done. For example, an image of the inspection target product is acquired as a tomographic image horizontal to the substrate, an actual measurement value of the diameter of the inspection target product is acquired based on the tomographic image, and the pass / fail judgment is made by comparing with an expected value. (See Patent Document 1).
Special table 2003-514233 gazette

In the above-described conventional X-ray inspection apparatus, it is difficult to specify an optimal tomographic image to be inspected, and as a result, high-accuracy inspection cannot be performed.
Specifically, in order to inspect a small inspection object such as a BGA solder bump, it is necessary to accurately specify an inspection position including an image to be inspected. However, as disclosed in Patent Document 1 described above, the inspection position is calculated even if a configuration in which the solder amount is calculated based on the horizontal slice image and the best horizontal slice image is obtained from the calculated solder distribution is adopted. Cannot be accurately identified. That is, defective solder may be included in the solder bumps to be inspected, but the distribution of solder is different between defective and non-defective products, and the distribution does not become a stable value. In this configuration, since the inspection position of the inspection target product is determined based on the information of the inspection target product, the accuracy for determining the inspection position is affected by the quality of the inspection target product. Therefore, it is impossible to make a pass / fail judgment with high reliability.

In addition, when inspecting products to be inspected that require 100% inspection, such as parts mounted on automobiles, it is extremely important to perform high-precision inspection automatically and at high speed in order to improve production efficiency.
The present invention has been made in view of the above problems, and an object of the present invention is to provide an X-ray inspection apparatus, an X-ray inspection method, and an X-ray inspection program capable of automatically performing high-precision inspection at high speed.

  In order to achieve at least one of the above objects, a plurality of X-ray images obtained by imaging detectors on a substrate by arranging detectors at different positions are acquired, and a reconstruction operation is performed based on each X-ray image. According to the reconstruction calculation, reconstruction information (for example, a three-dimensional image) indicating information on the structure of the substance in the irradiation range is obtained. According to this information, information on the wiring pattern formed on the substrate is acquired. be able to.

  Since the wiring pattern is formed in a plane parallel to the surface of the substrate, if information on the wiring pattern can be acquired, an arbitrary position can be accurately acquired based on the relative relationship with the wiring pattern. Can do. As a result, it is possible to accurately determine the inspection position having a predetermined relationship with respect to the wiring pattern, and to accurately perform the pass / fail determination based on the reconstruction information of the inspection position.

  Here, in the X-ray image acquisition means, an inspection object is arranged within the X-ray output range, and an X-ray image obtained by photographing the transmitted X-rays with a detector is acquired. Further, X-rays are captured by detectors arranged at different positions, and a plurality of X-ray images are acquired by acquiring X-ray images captured at each position. By using the fact that each X-ray image has a different imaging position and using a known method, it is possible to perform an inspection by performing a reconstruction operation on the inspection target product.

  In order to acquire an X-ray image, it suffices if X-rays from an X-ray source can be irradiated to an inspection target product. In order to make the structure of the X-ray inspection apparatus simple and increase the speed of inspection by reducing the number of movable parts, an X-ray source capable of outputting X-rays within a predetermined solid angle range is adopted. Is preferred. In this configuration, the X-ray detector may be arranged so that the detection surface is included in the X-ray output range. That is, by using an X-ray tube that irradiates a wide range of X-rays rather than using an X-ray tube with a limited irradiation range, the angle change or movement of the X-ray source can be performed when taking an X-ray image. It is possible to acquire a plurality of X-ray images without accompanying.

  As such an X-ray source, for example, a transmission type open tube may be employed. That is, in a transmissive open tube, X-rays are generated by electrons colliding with a thin target, and almost all directions (solid angle 2π) are within the output range when the X-rays pass through the target and are output to the outside. Become. Of course, in most cases, the solid angle 2π is not necessary as an irradiation range for imaging the object to be inspected, and an X-ray source that irradiates X-rays at a solid angle including at least detection surfaces arranged at different positions should be adopted. However, as the solid angle increases, the number of inspection target products to which the present invention can be applied increases, and the versatility increases.

  Of course, various device configurations can be used for acquiring X-ray images, and various devices can be used as long as X-ray images can be acquired by detectors arranged at different positions. It is. Further, in order to arrange the detectors at different positions, one detector may be moved, or the detectors may be fixedly arranged at a plurality of positions in advance, or a plurality of detections may be performed. The vessel may be moved.

  When taking an X-ray image, it is only necessary that the X-ray image can be arranged so that a desired product to be inspected is included. For this purpose, it is preferable to employ a configuration in which the inspection target product can be easily moved. For example, a configuration in which a plurality of target products are placed on an XY stage or the like can be employed. In the present invention, since the inspection object is photographed by detectors arranged at different positions, it is necessary to rotate the inspection object to obtain an X-ray image necessary for performing the reconstruction calculation. Absent. Accordingly, it is possible to bring the X-ray source and the inspection target product closer to each other as compared with the X-ray inspection apparatus that rotates and moves the inspection target product. For this reason, it is possible to easily acquire an X-ray image with a large enlargement ratio on the detection surface of the X-ray image acquisition means, and it is possible to carry out a highly accurate inspection.

  The X-ray image only needs to indicate the X-ray transmitted through the inspection target product, and it is only necessary that the X-ray image can be acquired by detectors arranged at different positions. As these detection means, for example, a sensor that measures the intensity of X-rays using a two-dimensionally arranged CCD can be employed. Further, the detection surface only needs to face the focal point of the X-ray source. When the inspection target product is arranged on a flat surface, the detection surface is placed at a plurality of positions having different relative relationships with the arranged flat surface. Arrange. Of course, the detector can employ various configurations such as an image intensifier.

  In the present invention, the information regarding the three-dimensional structure (reconstruction information) of the inspection target product is acquired by executing the reconstruction calculation by the reconstruction calculation means. Therefore, in the X-ray image acquisition means, the inspection target product A plurality of X-ray images are acquired so that information regarding the three-dimensional structure can be acquired. For example, in each of the detectors disposed at different positions, if the straight line connecting the detector and the focal point of the X-ray source is a different straight line, the three-dimensional structure of the inspection object is acquired based on two X-ray images. What is necessary is just to acquire an X-ray image by making a detector into such arrangement | positioning. Of course, the method for acquiring the three-dimensional structure is not particularly limited, and a method of sequentially calculating a two-dimensional image may be employed.

  If X-ray images taken from different directions are used, the reconstruction calculation means can execute the reconstruction calculation. When this reconstruction calculation is performed, a predetermined value is applied to the inspection target product. It is preferable to take an X-ray image from a position having symmetry. For this purpose, the position when the detection surface of the X-ray detector is rotated around an axis having a predetermined relationship with the plane on which the inspection object is arranged (hereinafter referred to as a rotation position). A detection surface is disposed on the surface. More specifically, a straight line connecting the focal point of the X-ray source and the center of the X-ray irradiation range is used as an axis, and the rotational position may be assumed on the circumference of a predetermined radius centered on this axis. Of course, the rotational position may be assumed on the circumference of a predetermined radius centered on an axis perpendicular to this axis.

  As described above, if the detection surfaces are arranged at a plurality of rotational positions, the inspection object can be photographed from a rotationally symmetric position, and three-dimensional in consideration of the rotational symmetry of the photographed X-ray image. It becomes possible to analyze the structure. In this configuration, X-ray images are acquired at a plurality of rotational positions, but the inspection target product is not rotated in order to acquire X-ray images. Accordingly, it is possible to inspect the inspection object by simply moving the inspection object in a plane with a simple configuration, and the processing can be performed at high speed even when inspecting a large number of inspection objects. .

  In the X-ray inspection apparatus of the present invention, the quality is determined based on the reconstruction information obtained by the reconstruction calculation. As this pass / fail determination, it is possible to employ a configuration for inspecting a tomographic image to be inspected, a cross-sectional area, a shape, a bridge in soldering, the presence or absence of contact failure, and the like. In this pass / fail judgment, it is necessary to specify an inspection position for performing an inspection, for example, a position of a tomographic surface to be inspected, a position to be inspected for the presence of bridges or poor contact in soldering, and the like.

  Therefore, although the inspection position is determined by the determining means, it is only necessary that the inspection position can be determined based on the wiring pattern information. That is, in the present invention, it is assumed that a component on the board is a product to be inspected, and the product to be inspected is mounted on the substrate in a state where the wiring pattern is already wired on the substrate. The wiring pattern does not change regardless of quality. Therefore, if the inspection position is specified based on the wiring pattern, the inspection position can be accurately determined regardless of the quality of the inspection target product. In addition, since the positional relationship between the wiring pattern and the inspection position can be specified in advance, the inspection position can be automatically determined based on the wiring pattern information. As a result, high-precision inspection can be automatically performed at high speed.

  The inspection position determined by the determination means can be specified by various methods. For example, the inspection position may be specified from the position of the wiring pattern in the direction perpendicular to the substrate. That is, there are various wiring patterns depending on the board, but the wiring pattern is wired in parallel to the board. Therefore, if the position of the wiring pattern is specified in the direction perpendicular to the board, the wiring pattern An arbitrary position in a direction perpendicular to the substrate can be accurately specified by the relative distance.

Therefore, to identify the position of the wiring pattern in the direction perpendicular to the substrate from the information of the wiring pattern of the substrate contained in a direction parallel to the tomographic image with respect to the base plate, and employs a configuration of determining the inspection location May be. According to this configuration, since the inspection position can be accurately determined based on the position of the wiring pattern, the wiring pattern has a predetermined relationship such as when soldering is performed on the pads included in the wiring pattern. A certain inspection object can be inspected accurately.

  More specifically, when inspecting the tomographic image to be inspected, the cross-sectional area, the shape, the bridge in soldering, the presence or absence of poor contact, etc., as described above, pass / fail in the reconfiguration information after the reconfiguration calculation. Use a part that contains information that can be determined. Since such a part can specify in advance which part of the product to be inspected, if the relationship between this part and the position of the wiring pattern is specified in advance, the wiring pattern The inspection position can be accurately determined based on the position.

  In addition, since the wiring pattern is formed in a plane parallel to the substrate as described above, a plurality of tomographic images in a direction parallel to the substrate and having different positions in the direction perpendicular to the substrate. If a tomographic image is acquired and an image including a wiring pattern is extracted from each tomographic image, the position of the tomographic image (the position in the direction perpendicular to the substrate) is the position of the wiring pattern. Can do. When a plurality of tomographic images include a wiring pattern image, various methods such as selecting a tomographic image in which the wiring pattern is most clearly formed can be employed.

Furthermore, as the wiring pattern information, various types of information can be used. As a preferable example, a characteristic amount characteristic to the wiring pattern image can be used. For example, if the feature amount is extracted, wiring pattern information can be specified in the reconstructed reconfiguration information. That is, an image of the wiring pattern can be extracted from the image formed by the reconstruction information. As a result, the position of the wiring pattern can be specified, and the inspection position can be accurately specified by the relative relationship with this position.

To identify the information of the wiring pattern from the reconstructed information the reordering is possible to employ various information, for example, identify and whether the information of the wiring pattern on the basis of the edge information of images May be. That is, according to the reconstructed reconstruction information, it is possible to create a tomographic image for an arbitrary plane, and when this tomographic image includes a wiring pattern, the boundary of the wiring should be extracted as an edge. is there. Therefore, by referring to the edge information of the image, it can be easily specified whether or not the information included in the reconstruction information is wiring pattern information.

  Here, various configurations can be adopted as the configuration for extracting the edge information of the image. For example, it is possible to employ a configuration in which edge pixels are detected by an edge extraction filter (Sobel filter, Prewitt filter, Roberts filter, Laplacian filter, etc.). Of course, when extracting edge pixels, various configurations such as performing blurring processing once to reduce the influence of noise and artifacts can be employed.

  Furthermore, various configurations can be adopted for determining whether or not the wiring pattern is based on the edge, and it may be determined based on the amount of the edge pixel, or the edge direction and the edge pixel may be determined. It may be determined based on whether the appearance is random or the like, or a configuration may be adopted in which it is determined whether the pattern matches a predetermined edge pattern by pattern matching.

  Of course, the information for determining whether or not the wiring pattern is not limited to the edge information, various information can be used. For example, you may determine whether it is a wiring pattern by the brightness of an image. That is, if the image of the wiring pattern is formed brighter than the surroundings, the image is scanned in a direction perpendicular to the substrate, and the position where the brightness becomes maximum can be determined as the position of the wiring pattern.

  Further, spatial frequency analysis of an image may be used. For example, if the image contains a wiring pattern and the spatial frequency of the image takes a predetermined range, the image is Fourier transformed to calculate a spectrum having the predetermined spatial frequency, or integrate the spectrum. A configuration can be adopted. That is, the spectrum and the integrated value are compared with a plurality of tomographic images, and the tomographic image closest to the spectrum and the integrated value in the case of the wiring pattern image may be the tomographic image including the wiring pattern.

  Furthermore, a histogram of image data may be used. For example, when an X-ray image is expressed by image data with X-ray intensity as a gradation value, a histogram is calculated for the gradation value for each pixel. In this histogram, when the distribution is discrete or the variance is small, a pattern of a specific density is concentrated. Therefore, a histogram of gradation values for each pixel is calculated for the X-ray image, and the histogram is in the vicinity of the gradation value corresponding to the density when the wiring pattern is included in the image (within a predetermined range before and after this gradation value). Can be determined whether or not the tomographic image is a wiring pattern image.

  Further, it may be determined whether or not the wiring pattern is an image of the wiring pattern using the fact that the boundary of the wiring pattern is linear. For example, a configuration is adopted in which a linear pattern is detected from an image using Hough transform and the wiring pattern image is determined when the straight line is longer than a predetermined length or a predetermined pattern. Is possible.

  Furthermore, the wiring pattern information used when determining the inspection position may be information on the wiring pattern at an arbitrary position, but information on a preferable part is used to extract the wiring pattern information more reliably. A configuration may be adopted. That is, in the reconstruction information obtained by the reconstruction operation, the quality of the information varies depending on the part of the reconstruction information. For example, when the number of X-ray images for performing the reconstruction calculation is small, an image (artifact) that should not originally exist around a substance having a high X-ray absorption rate may be formed.

In order to eliminate the influence of this artifact, the influence of artifacts based on the information of the wiring pattern in a predetermined following sites, determining the test position. In other words, artifacts may occur in the vicinity of a substance having a large X-ray absorption rate or in a region where a substance having a high X-ray absorption rate is dense. Therefore, information on the wiring pattern in a part away from such a part is used. To do. As a result, it is possible to determine the inspection position while eliminating the influence of the artifact.

  Here, it is only necessary that the image can be analyzed while suppressing the influence of the artifact. Therefore, it is not necessary to quantitatively measure the influence of the artifact. For example, in a region selected as an analysis target, when the number of images of a substance having a large X-ray absorption rate is less than a predetermined number, When the distance to the target region is equal to or greater than a predetermined distance, the influence of the artifact may be a predetermined region or less.

Although the case where the present invention is realized as an apparatus has been described above, the present invention can also be applied to a method for realizing such an apparatus. As an example may be configured to realize METHODS. Of course, the substantial operation is the same as that of the apparatus described above . It is X-ray inspection apparatus such as the following may also be implemented alone, it is applied to a method, or a similar method may also be utilized in a state of being incorporated into other devices, idea of the present invention However, the present invention is not limited to this and includes various modes.

Of course, the embodiment of the invention can be changed as appropriate, such as software or hardware. In the case of software for controlling the above method as an embodiment of the idea of the invention, it naturally exists and is used also on the recording medium on which the software or software is recorded. As an example may be configured to implement the functions in software.

  The software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium that will be developed in the future. The same is true for the replication stage of primary replicas and secondary replicas. In addition, even when the communication apparatus is used as the supply device, the present invention is not used. Further, even when a part is software and a part is realized by hardware, the idea of the invention is not completely different, and a part is stored on a recording medium and is appropriately changed as necessary. It may be in a form that is read.

Here, embodiments of the present invention will be described in the following order.
(1) Configuration of the present invention:
(2) X-ray inspection process:
(3) Other embodiments:

(1) Configuration of the present invention:
FIG. 1 is a schematic block diagram of an X-ray inspection apparatus 10 according to the present invention. In this figure, the X-ray inspection apparatus 10 includes an X-ray generator 11, an XY stage 12, an X-ray detector 13 a, and a transfer device 14, and each part is controlled by a CPU 25. That is, the X-ray inspection apparatus 10 has a control system including a CPU 25 as an X-ray control mechanism 21, a stage control mechanism 22, an image acquisition mechanism 23, a transport mechanism 24, a CPU 25, an input unit 26, an output unit 27, a memory 28, and a height sensor. And a control mechanism 29. In this configuration, the CPU 25 can execute a program (not shown) recorded in the memory 28, control each unit, and perform predetermined arithmetic processing.

  The memory 28 is a storage medium capable of storing data, in which inspection object data 28a and imaging condition data 28b are recorded in advance. The inspection target data 28a is data indicating the position of the inspection target product. In this embodiment, the inspection target data 28a is data for disposing a plurality of bumps disposed on the substrate in the field of view of the X-ray detector 13a. . That is, in this embodiment, bumps regularly arranged on the substrate are used as inspection objects. In the present embodiment, the inspection target data 28a also includes data indicating the thickness of the substrate on which the bumps are mounted.

  The imaging condition data 28b is data indicating conditions when X-rays are generated by the X-ray generator 11, and includes an applied voltage to the X-ray tube, imaging time, and the like. The memory 28 can store various data generated in the process of the CPU 25. For example, X-ray image data 28c indicating an X-ray image acquired by the X-ray detector 13a can be stored. The memory 28 only needs to be able to store data, and various storage media such as RAM and HDD can be employed.

  The X-ray control mechanism 21 can generate predetermined X-rays by referring to the imaging condition data 28b and controlling the X-ray generator 11. The X-ray generator 11 is a so-called transmissive open tube, and outputs X-rays from the focal point F, which is the output position of the X-rays, in almost all directions, that is, in the range of the solid angle 2π.

  The stage control mechanism 22 is connected to the XY stage 12, and controls the XY stage 12 based on the inspection object data 28a. In this embodiment, the product to be inspected is a bump, and a substrate on which the bump is disposed is placed on the XY stage 12 to make a pass / fail judgment. Therefore, the stage control mechanism 22 controls the XY stage 12 so that the bumps are included in the field of view of the X-ray detector 13a with reference to the inspection object data 28a when determining pass / fail.

  Further, the transport mechanism 24 controls the transport device 14 to carry the substrate 12a into the XY stage 12. That is, the process of transporting the substrate 12a in one direction by the transport device 14, inspecting a plurality of bumps on the substrate 12a in the XY stage 12, and continuously unloading the substrate 12a after the inspection by the transport device 14 is performed. It is configured so that it can be implemented.

  The image acquisition mechanism 23 is connected to the X-ray detector 13a, and acquires an X-ray image of a product to be inspected based on a detection value output from the X-ray detector 13a. The acquired X-ray image is stored in the memory 28 as X-ray image data 28c. The X-ray detector 13a according to the present embodiment includes a two-dimensionally distributed sensor, and can generate X-ray image data indicating a two-dimensional X-ray distribution from the detected X-rays.

  In the present embodiment, since the X-ray image is acquired so that the bump is included in the field of view of the X-ray detector 13a, the X-ray image includes a transmission image of the bump. In addition, a wiring pattern is formed on the substrate 12a by an electric conductor such as copper, and the X-ray image includes a transmission image of the wiring pattern. Note that the bumps in this embodiment are melted in the previous process and joined to solder formed in advance on the pads of the wiring pattern. Therefore, it is a good product if both solders are melted and joined, and if it is insufficiently joined, it is a defective product.

  The X-ray detector 13a is connected to a rotating mechanism 13b via an arm. The X-ray detector 13a has a circumference of a radius R around an axis A extending vertically upward from the focal point F of the X-ray generator 11. The top can be rotated. The rotation mechanism 13b is controlled by the θ control unit 23a of the image acquisition mechanism 23. The detection surface is oriented so that a straight line extending from the focal point F of the X-ray generator 11 to the center of the detection surface of the X-ray detector 13a is orthogonal to the detection surface.

  The output unit 27 is a display that displays the X-ray image and the like, and the input unit 26 is an operation input device that accepts user input. That is, the user can execute various inputs via the input unit 26, and various calculation results obtained by the processing of the CPU 25, X-ray image data, pass / fail judgment results of the inspection target product, and the like are output to the output unit 27. Can be displayed.

  The height sensor control mechanism 29 is connected to the height sensor 15, and based on the inspection object data 28a, the distance between the focal point F of the X-ray generator 11 and the substrate 12a (the height in the z direction: this embodiment). In the form, the height of the focus F is “0”). The height sensor 15 may be any sensor that measures this distance, and various sensors can be employed. In addition, since the measurement of the said height does not require a highly accurate measurement so that it may mention later, you may measure the height of the board | substrate 12a in arbitrary positions, and the part by which the test object bump was mounted The height of the substrate 12a may be measured by using various configurations.

  The CPU 25 can execute predetermined arithmetic processing according to various control programs stored in the memory 28, and in order to inspect the inspection target product, the transport control unit 25a, the X-ray control unit 25b, and the stage control shown in FIG. The calculation in the part 25c, the image acquisition part 25d, the quality determination part 25e, and the height sensor control part 25f is performed. The transport control unit 25a controls the transport mechanism 24 to supply the substrate 12a to the XY stage 12 at an appropriate timing, and also drives the transport device 14 at an appropriate timing to transfer the inspected substrate 12a to the X-Y stage 12. -Remove from Y stage 12.

  The X-ray control unit 25 b acquires the imaging condition data 28 b and controls the X-ray control mechanism 21 to output predetermined X-rays from the X-ray generator 11. The stage control unit 25c acquires the inspection object data 28a, calculates coordinate values for arranging the bumps in the field of view of the X-ray detector 13a, and supplies the coordinate values to the stage control mechanism 22. As a result, the stage control mechanism 22 moves the XY stage 12 so that this coordinate value is included in any field of view of the X-ray detector 13a.

  The image acquisition unit 25d instructs the θ control unit 23a of the image acquisition mechanism 23 to rotate the X-ray detector 13a. Further, X-ray image data 28 c acquired by the image acquisition mechanism 23 is recorded in the memory 28. The pass / fail determination unit 25e performs a reconstruction calculation based on the X-ray image data 28c, and determines whether the bump is a non-defective product or a defective product based on the reconstruction calculation result. At this time, a process for accurately specifying the inspection position where the bump is to be inspected is performed based on the reconstruction calculation result, and as a result, accurate pass / fail judgment can be performed.

  The height sensor control unit 25f acquires the inspection target data 28a, specifies the position where the inspection target bump is placed on the substrate 12a, and instructs the height sensor control mechanism 29. At this time, the XY stage 12 is moved by the stage control mechanism 22, and the position at which the bump to be inspected is placed on the substrate 12 a is disposed at a position that can be measured by the height sensor 15. Thereafter, the height sensor control mechanism 29 controls the height sensor 15 to acquire the distance between the focal point F of the X-ray generator 11 and the lower surface of the substrate 12a.

(2) X-ray inspection process:
In the present embodiment, the quality of the inspection target product is determined according to the flowchart shown in FIG. In the present embodiment, a large number of substrates 12 a are transported by the transport device 14, and the bumps on the substrate 12 a are sequentially inspected on the XY stage 12. For this reason, at the time of inspection, first, at step S100, the transfer control unit 25a issues an instruction to the transfer mechanism 24, and the transfer device 14 transfers the substrate 12a to be inspected onto the XY stage 12.

  Next, the variable n is initialized to “0” in order to move the plurality of bumps to be inspected into the field of view of the X-ray detector 13a and acquire an X-ray image (step S105). Subsequently, the image acquisition unit 25d instructs the θ control unit 23a to drive the rotation mechanism 13b to move the X-ray detector 13a to a predetermined rotation position (step S110). In the present embodiment, the rotation angle θn is defined as θn = (n / N) × 360 °, and the angle θ = 0 ° is predetermined.

  The variable n is an integer whose maximum value is N. Therefore, the X-ray detector 13a rotates by 360 ° / N. N + 1 is the number of rotational positions at which an X-ray image is taken, and may be determined from the required inspection speed and inspection accuracy, the degree of artifact, and the outer shape (axial symmetry) of the inspection target product. For example, N = 31 or the like (number of times of imaging 32) can be adopted, but an X-ray image is acquired with a smaller number of times of imaging (for example, N = 4, number of times of imaging 5), and pseudo X-ray image is obtained by interpolation calculation A configuration in which the number of sheets is increased may be adopted.

When the rotation operation of the X-ray detector 13a is performed, the XY stage 12 is moved so that the inspection target bump is included in the field of view of the rotated detector (step S115). At this time, the stage control unit 25c refers to the inspection object data 28a and instructs the stage control mechanism 22 so that the coordinates (x _i , y _i ) are the center of the visual field of the X-ray detector 13a. As a result, the stage control mechanism 22 moves the XY stage 12 and arranges the coordinates (x _i , y _i ) at the center of the visual field of the X-ray detector 13a.

That is, the coordinates (x _i , y _i ) are coordinates set in advance on the substrate 12a in order to move the bump to be inspected into the visual field of the X-ray detector 13a, and the X-ray detector 13a is rotated as described above. The center of the visual field when arranged at the angle θn can be obtained from the relative relationship between the X-ray detector 13 a and the focal point F of the X-ray generator 11. Therefore, by moving the coordinates (x _i , y _i ) into the field of view of the X-ray detector 13a, the position of the substrate 12a is controlled so that transmission images of a plurality of bumps are acquired by the X-ray detector 13a. be able to.

  3 and 4 are diagrams for explaining this example, and are diagrams showing the positional relationship between the coordinate system and the X-ray detector 13a and the X-ray generator 11. FIG. In these figures, the plane of movement by the XY stage 12 is the xy plane, and the direction perpendicular to this plane is the z direction. 3 is a view of the z-x plane, and FIG. 4 is a view of the xy plane.

  As shown in FIG. 3, the detection surface of the X-ray detector 13 a is oriented so as to be perpendicular to a straight line l connecting the center and the focal point F. That is, it is inclined with respect to the axis A, and a predetermined angle (inclination angle) α is given to the xy plane and the detection surface. Since the straight line l corresponds to the center of the visual field of the X-ray detector 13a, the visual field region FOV can be specified from the rotation angle θn of the X-ray detector 13a as shown in FIG.

That is, since a predetermined region including the intersection of the straight line l and the xy plane becomes a visual field region FOV of the X-ray detector 13a, each rotation angle is assumed if the rotation angle θn of the X-ray detector 13a is assumed. The visual field region FOV can be determined from the visual field center corresponding to θn and a predetermined region around it. Therefore, the stage control mechanism 22 moves the XY stage 12 so that the center of the visual field area FOV and the coordinates (x _i , y _i ) coincide.

  In FIG. 4, the straight line extending from the center O in the −y direction is θ = 0, the clockwise rotation angle is θn, and the viewing areas of θn = 0 °, 90 °, 180 °, and 270 ° are shown. These are FOV1 to FOV4, respectively. Of course, in step S115, various control methods can be employed as long as the bumps to be inspected can be arranged in the field of view of the X-ray detector 13a. In general, since a plurality of bumps are included in the visual field area FOV, when transmission images of common bumps are taken in different visual field areas, all the common bumps are inspected. It is preferable.

When the coordinates (x _i , y _i ) are arranged at the center of the visual field of the X-ray detector 13a in step S115, the rotation angle θn is controlled by the X-ray detector 13a under the control of the X-ray control unit 25b and the image acquisition unit 25d. The X-ray image P _θn is taken (step S120). That is, the X-ray control unit 25b acquires the imaging condition data 28b and instructs the X-ray control mechanism 21 to output X-rays under the conditions indicated by the imaging condition data 28b. As a result, the X-ray generator 11 outputs X-rays in the range of the solid angle 2π, so the image acquisition unit 25d acquires the X-ray image detected by the X-ray detector 13a.

When shooting an X-ray image P _.theta.n rotation angle .theta.n at step S120, the variable n is determined whether or not has reached the maximum value N (step S125), if it is determined to have reached the maximum value N variable n is incremented (step S130), and the processing after step S110 is repeated. When it is determined in step S125 that the variable n has reached the maximum value N, the necessary number of times of shooting has been completed. Therefore, in the present embodiment, the nondefective determination unit 25e performs the reconstruction operation of the 3-dimensional image by using the X-ray image _P θ0 ~P θN (step S135).

The reconstruction calculation only needs to reconstruct the three-dimensional structure of the bump, and various processes can be employed. For example, a filter-corrected back projection method can be employed. In this process, first, it carried out Fourier transform on one of the X-ray image P _.theta.0 to P _.theta.N, multiplied by the filter correction function in the frequency space relative results obtained by the Fourier transform. Furthermore, an image subjected to filter correction is obtained by performing inverse Fourier transform on this result. As the filter correction function, a function for enhancing the edge of the image can be adopted.

Subsequently, the image after the filter correction is back-projected into a three-dimensional space along a locus on which the image is projected. That is, since the locus corresponding to the image at a certain position on the detection surface of the X-ray detector 13a is a straight line connecting the focal point F of the X-ray generator 11 and this position, the image is back-projected onto this straight line. . Doing more backprojection for all X-ray image P _.theta.0 to P _.theta.N, X-ray absorption coefficient distribution of a portion bumps are present in the three-dimensional space is emphasized, the three-dimensional shape of the bumps can be obtained.

  Next, a process for specifying an inspection position for determining pass / fail is performed. In other words, in order to accurately determine the quality of bumps using the reconstruction calculation results, it is necessary to inspect a part where the difference between a good product and a defective product clearly appears, and this site is specified as the inspection position. To do. In the present embodiment, a bump inspection position is set to the same height (position in the z direction) as the wiring pattern of the substrate 12a.

FIG. 5 is an explanatory diagram for explaining the bumps and their quality in this embodiment. State of the upper as viewed substrates 12a from a lateral direction (x or y-direction) this figure, the bottom shows the state of viewing the tomographic image of the position T ₀ from the longitudinal direction (z-direction) schematically. In the upper part of this figure, a resist 12e and a pad 12d are formed on the upper surface of the substrate 12a. The pad 12d is an end portion of a wiring pattern formed of a conductor such as copper and is a portion that becomes a contact point with the bump 12c. The resist 12e is a resin applied between the pads 12d and on the upper surface of the wiring pattern, and insulates the surface of the wiring pattern as necessary.

  The bump 12c is a ball-shaped solder formed on the lower surface of the chip 12b in advance, and the chip 12b is mounted on the substrate 12a by making the contact of the chip 12b and the pad 12d conductive through the bump 12c. It is like that. In order to perform this mounting, a solder land is previously formed on the pad 12d, and the land and the unmelted bump are brought into contact with each other, and both are melted and bonded. Therefore, a state where the solder is reliably melted and conduction is ensured is a non-defective product.

  In FIG. 5, the left bump 12c is a good product and the right bump 12c is a defective product. This quality can be determined by various methods. For example, it is possible to make a pass / fail judgment using the fact that the resist 12e shown in FIG. 5 is a so-called normal resist that does not exist around the pad. That is, in the normal resist, there is no solder around the pad 12d before the solder is melted. However, when the solder is properly melted, the bump 12c becomes a barrel shape as shown on the upper left side of FIG. It penetrates between 12d and the resist 12e.

On the other hand, when the solder does not melt or is insufficiently melted, the bump 12c remains in a ball shape as shown on the upper right side of FIG. 5, and does not enter between the pad 12d and the resist 12e. This situation can be easily observed in the tomographic image at the position T ₀ shown in the lower part of FIG. That is, when the bump 12c is a non-defective product, solder exists in a substantially circular shape around the pad 12d as shown on the lower left side of FIG. 5, and when the bump 12c is a defective product, it is shown on the lower right side of FIG. Thus, there is no solder around the pad 12d.

Therefore, the inspection position to the position T ₀ shown in FIG. 5, by analyzing a tomographic image of the position, it is possible to determine the quality of easily and reliably bumps 12c. That is, in the X-ray image, because the density of the image by the absorption of X-ray different, by looking at the tomographic image of the position T _0, whether the solder there be easily observed around the pad 12d Can do. Here, the wiring pattern such as pads 12d are thin, identifies the precise position T _0, observing the periphery of the pad 12d is an extremely important factor for the accuracy of the determination acceptability.

Therefore, in order to accurately specify the inspection position, in the present embodiment, the inspection position is first roughly specified. Therefore, the nondefective determination unit 25e performs an instruction to the height sensor control unit 25f, the coordinates (x _i, y _i) to measure the height Z _opt of the substrate 12a in (step S140). That is, since the coordinates (x _i , y _i ) indicate the part on the substrate 12a on which the bump to be inspected is placed on the xy plane, this part is disposed at the measurement target position of the height sensor 15. As described above, the X-ray control mechanism 21 controls the XY stage 12 to move the substrate 12a.

  As shown in FIG. 3, the height sensor 15 is disposed below the substrate 12a, and includes a laser output device 15a and a line sensor 15b. The laser output device 15a can output laser light toward the substrate 12a, and the line sensor 15b is a sensor that detects the laser light reflected by the substrate 12a. The line sensor 15b includes a plurality of sensors arranged along a certain direction, and the horizontal component of the output direction of the laser light and the direction in which the line sensor is arranged coincide with each other.

Therefore, when the reflected laser beam fluctuates as the substrate 12a fluctuates in the vertical direction, the position where the reflected laser beam reaches the line sensor 15b also fluctuates (for example, when the substrate 12a fluctuates downward, the locus of the laser beam). Varies from a solid line to a broken line). Therefore, the position where the brightness of the reflected laser light detected by the line sensor 15b is the maximum is the arrival position of the reflected laser light, and the distance (height Z _opt ) between the substrate 12a and the focal point F based on this arrival position. Measure.

In the present embodiment, the height Z _opt of the substrate 12a is measured at the coordinates (x _i , y _i ). If the height Z _opt is almost the same at any position on the substrate 12a, The height Z _opt may be measured at an arbitrary position other than the coordinates (x _i , y _i ). Since the wiring pattern is formed on the upper surface of the substrate 12a, the pass / fail judgment unit 25e further refers to the inspection object data 28a to obtain the thickness Z _offset of the substrate 12a (step S145).

Since the sum of the height Z _opt and the thickness Z _offset acquired as described above corresponds to a rough distance from the focal point F of the X-ray generator 11 to the wiring pattern, the pass / fail judgment unit 25e determines this distance. A plurality of tomographic images are analyzed in order to obtain an accurate height from the focal point F to the wiring pattern in the vicinity and to obtain an inspection position. In the present embodiment, in order to eliminate as much as possible the influence of the artifacts generated by the reconstruction calculation, a region with little influence of the artifacts is set as the analysis region ROI (step S150).

  The analysis region ROI can be determined based on various methods. In the present embodiment, in the tomographic image in which a plurality of bumps are arranged, the bump image and this image are displayed on only one of the upper, lower, left, and right sides. The area where the bump image and the artifact do not exist is set as the analysis region ROI in the other three directions. The analysis region ROI is a region for specifying the height of the wiring pattern, and is set at a position where the wiring pattern image can be included in the tomographic image parallel to the xy plane.

6A to 6F are diagrams showing examples of a plurality of tomographic images in the vicinity of the position T ₀ , and the analysis region ROI is shown in FIG. 6E. In this embodiment, the analysis region ROI is a portion where there are no bump images and artifacts on three sides, and there is an image of the wiring pattern, and any of the two locations shown in FIG. 6E can be adopted as the analysis region ROI. It is. Needless to say, here, it is sufficient that the analysis can be performed while suppressing the influence of the artifact, and the artifact does not need to be exactly “0”. That is, as compared with the region R sandwiched between the bump images, the ROI shown in FIG. 6E has fewer artifacts, and thus a good analysis can be performed.

In any case, in step S150, the analysis region ROI is specified in the xy plane according to a predetermined rule. When the analysis region ROI is determined, analysis is performed for each of a plurality of tomographic images. Therefore, first, the coordinate z indicating the height from the focal point F is set to “−Z / 2 + Z _opt + Z _offset”.
"Z is a numerical value indicating the fluctuation range of the coordinate z, and the coordinate z is changed in the range of -Z / 2 to Z / 2 with Z _opt + Z _offset as the center. Become.

  Next, the pass / fail determination unit 25e acquires a tomogram F (x, y, z) from the reconstruction information after the reconstruction calculation (step S160). Here, x and y are a plurality of values with the coordinate value in the analysis region ROI as a range, and z is a value set in step S155 (step S180 during the loop process). By this processing, a tomographic image in the analysis region ROI at the coordinate z is acquired.

When the tomographic image F (x, y, z) is acquired, an edge extraction filter (for example, Sobel filter) is applied to the tomographic image F (x, y, z), and the edge image FE (x, y, z) is applied. ) Is acquired (step S165). Since the edge image FE (x, y, z) is an image having a significant value in the edge pixel with respect to the analysis region ROI at the coordinate z, in this embodiment, the gradation value ( The value E _tot (z) indicating the strength of the edge is acquired by adding the edge images FE (x, y, z)) (step S170).

When the edge intensity value E _tot (z) of the tomographic image at the coordinate z is calculated, it is determined whether or not the coordinate z exceeds “Z / 2 + Z _opt + Z _offset ” (step S175). If it is not determined in step S175 that the coordinate z exceeds “Z / 2 + _Zopt + _Zoffset ”, the coordinate z is incremented (step S180), and the processing after step S160 is repeated. When the coordinate z is judged to exceed the _{"Z / 2 + Z opt +} Z offset" at step S175, compares the edge intensity value E _tot (z) at each coordinate z, the edge intensity value E _tot (z) The coordinate z having the maximum value is set as the inspection position (step S185).

  That is, since the wiring pattern is formed on the substrate 12a with a predetermined width, the boundary of the wiring pattern becomes an edge in the tomographic image parallel to the xy plane. Further, in the tomographic image in which the coordinate z and the height of the wiring pattern coincide with each other, the wiring pattern image becomes clear, so that the image becomes sharp and the edge becomes clearer. Therefore, in the present embodiment, it is assumed that the coordinate z of the tomographic image having the strongest edge intensity in the analysis region ROI matches the coordinate z of the wiring pattern, and this coordinate z is used as the inspection position.

6A to 6F show this example, and the coordinate z increases in the order of FIGS. 6A to 6F. In this example, the image of the wiring pattern is unclear in FIG. 6A, and many edge pixels are not detected in the analysis region ROI. As the coordinate z increases with FIGS. 6B to 6F, the edges in the wiring pattern of the analysis region ROI gradually become clearer. In this example, the edge intensity value E _tot (z) is maximized around FIGS. 6C to 6E.

  The coordinates z in FIGS. 6C to 6E coincide with the coordinates z of the wiring pattern. In the tomographic images at these coordinates z, does the solder enter the periphery of the pad 12d as shown in FIGS. 6C to 6E? It is possible to reliably determine whether or not. Therefore, after specifying the coordinate z serving as the inspection position by the above-described processing, the pass / fail determination unit 25e acquires a tomographic image of the bump at the coordinate z and performs pass / fail determination (step S190).

  That is, it is determined based on the tomographic image whether or not the solder has permeated cleanly around the pad 12d shown in FIG. 5, and the quality of the bump 12c is determined. As described above, in the present invention, since the pass / fail judgment is performed after the position where the pass / fail judgment should be performed is automatically and accurately specified, it is possible to automatically perform a high-accuracy inspection at high speed. In the example shown in FIG. 6, the transmission image at a plurality of coordinates z can be used for pass / fail judgment due to the high resolution in the z direction. Of course, the resolution in the z direction requires the required inspection accuracy. It can be changed as appropriate according to the inspection speed.

(3) Other embodiments:
In the present invention, it is only necessary to acquire information on the wiring pattern of the board from the reconstruction calculation result and specify the inspection position based on this information, and various configurations other than the above embodiment can be adopted. For example, when acquiring an X-ray image at a plurality of rotational positions, the X-ray detector 13a may be acquired instead of rotating the X-ray detector 13a instead of rotating the X-ray detector 13a.

  FIG. 7 is a schematic configuration diagram of an X-ray inspection apparatus 100 that acquires X-ray images by a plurality of detectors. As shown in the figure, the configuration of the X-ray inspection apparatus 100 is common to the configuration of the X-ray inspection apparatus 10 in many respects, and the common configuration is denoted by the same reference numerals as those in FIG. The X-ray inspection apparatus 100 shown in FIG. 7 includes a plurality of X-ray detectors 130a as X-ray image acquisition means. Each X-ray detector 130 a is arranged so that the center of the detection surface exists on the circumference of the radius R centering on the axis A extending vertically upward from the focal point F of the X-ray generator 11.

  Also in the configuration shown in FIG. 7, each detection surface is inclined with respect to the axis A at an inclination angle α, and each detection surface is included in the X-ray output range by the X-ray generator 11. The rotational position of the X-ray detector 130a is defined similarly to the rotational position of the X-ray detector 13a in FIG. 1, and in the example shown in FIG. Although the X-ray detectors 130a are arranged at the four rotational positions, the X-ray detectors 130a may be arranged at a larger number or a smaller number of positions.

In the above configuration, the image acquisition mechanism 230 does not need to control the rotation mechanism. That is, in the imaging of the X-ray image by the X-ray image acquisition means, the rotation operation in step S110 is unnecessary, and the X-ray image P _θn for each θ is acquired only by the movement of the XY stage 12 by the stage control unit 25c. be able to. In such a configuration, it is not necessary to perform the θ rotation operation when photographing with the X-ray image acquisition means, so that the inspection can be advanced at a very high speed.

  Furthermore, in the above-described embodiment, an X-ray image is taken at each rotational position assuming a rotational position that is rotated about an axis perpendicular to the xy plane on which the bumps are arranged. Of course, the relative relationship between the bump and the detector is not limited to such a relationship. For example, an X-ray image at each rotational position may be taken assuming a rotational position obtained by rotating about an axis parallel to the xy plane. Even in this case, imaging may be performed so that a plurality of bumps are included in one X-ray image, a transmission image of the same bump is extracted from each image, and reconstruction calculation may be performed.

Furthermore, it is not essential that the inspection position is the same as the height of the wiring pattern, and it is only necessary that the inspection position can be specified based on the height of the wiring pattern. For example, determination may be performed to position T ₁ shown in FIG. 5 as the test position. The position T _1, when the bumps 12c is not melted, a position where the solder on the ball-shaped solder pad 12d is in contact, if the bump 12c is defective, the solder area at the position T ₁ is reduced . On the other hand, bump 12c
There If good, solder area at the position T ₁ increases.

Therefore, if this inspection position can be specified, the quality of solder can be determined with high accuracy. The position T ₁ can be identified in advance and the like diameters of the bumps 12c at an amount or unmelted state of the solder to be formed in advance on the pads 12d. Accordingly, if the predetermined offset is specified in advance from the coordinate z of the wiring pattern, the inspection position is specified by giving the offset after specifying the coordinate z of the wiring pattern by the same processing as in FIG. Is possible.

  Further, the quality determination method is not limited to the method based on the penetration of solder into the periphery of the pad 12d or the cross-sectional area of the solder as described above. For example, it is possible to make a pass / fail determination based on various indices such as the presence or absence of a bridge, the presence or absence of a void, and the shape of an outer shape at a certain inspection position. Of course, it is not essential to perform the pass / fail determination based on only one index, and the pass / fail determination may be performed by combining a plurality of indexes.

  Further, the image processing when extracting the wiring pattern is not limited to the above-described processing. For example, a configuration in which the coordinate z of the wiring pattern is specified based on the brightness of the tomographic image may be employed. That is, as shown in FIGS. 6A to 6F, since the X-ray absorption rate of the wiring pattern and the X-ray absorption rate of the resin around it are different, the densities of these images are different. 6A to 6F, when the coordinate z of the tomographic image changes and the wiring pattern image becomes clear, the portion of the wiring pattern becomes clear and bright.

  Thus, when the change in the brightness of an analysis region ROI is observed along the coordinate z, the brightness changes between an image including a wiring pattern and an image not including the wiring pattern. Therefore, if the variation in brightness caused by the wiring pattern is captured, the coordinate z of the wiring pattern can be specified.

  Further, as shown in FIGS. 6A to 6F, the spatial frequency changes depending on whether or not a clear wiring pattern is included in the analysis region ROI. Therefore, Fourier transform may be performed on the image in the analysis region ROI to analyze whether the spatial frequency is the spatial frequency of the image including the wiring pattern. Of course, it is possible to adopt various configurations such as a configuration in which a spatial frequency range to be analyzed is specified in advance and only a spectrum in the spatial frequency range is analyzed.

  Furthermore, a histogram is acquired for the gradation values in the analysis region ROI, and the number of gradation values that are significant histograms (the number of gradation values having a frequency distribution other than “0”) and its dispersion are artificial. It may be determined whether or not the image includes a structure, and the coordinate z of the wiring pattern may be specified by this determination.

  Furthermore, a pattern image indicating a wiring pattern may be registered in advance, and the coordinate z of the wiring pattern may be specified by performing pattern matching that compares this pattern image with the tomographic image of the analysis region ROI. Further, the Hough transform may be performed on the tomographic image in the analysis region ROI, and the coordinate z of the wiring pattern may be specified based on the presence / absence of the linear component corresponding to the boundary of the wiring pattern, the amount of the linear component, and the direction of the linear component. Of course, the coordinate z of the wiring pattern may be specified by using the direction of the edge, the degree of appearance of the edge, or the like depending on the state of the edge extracted as described above, and various configurations can be adopted. .

  Further, it is not essential to adopt the processing procedure shown in FIG. 2 above. Step S135 is skipped, and a reconstruction operation is performed before step S160 to calculate a two-dimensional slice image of the analysis region ROI at the coordinate z. May be. That is, the inspection position may be specified by performing the loop processing of steps S160 to S180 while sequentially calculating slice images of the analysis region ROI. Needless to say, in this case, an image at the inspection position is acquired by performing a reconstruction calculation before the quality determination. According to this configuration, it is possible to make a processing procedure for reconfiguring only the minimum necessary information.

1 is a schematic block diagram of an X-ray inspection apparatus according to the present invention. It is a flowchart of a X-ray inspection process. It is explanatory drawing explaining the structure of a X-ray inspection apparatus with a coordinate system. It is a figure which shows the example of a visual field area | region. It is explanatory drawing explaining the mode of a bump and its quality. It is a figure which shows the example of the some tomogram in the vicinity of a test | inspection position. It is a schematic block diagram of the X-ray inspection apparatus which acquires an X-ray image with a some detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... X-ray inspection apparatus 11 ... X-ray generator 12 ... XY stage 12b ... Chip 12c ... Bump 12d ... Pad 12e ... Resist 12a ... Substrate 13b ... Rotating mechanism 13a ... X-ray detector 14 ... Conveying device 15 ... Sensor 15b ... Line sensor 15a ... Laser output device 21 ... X-ray control mechanism 22 ... Stage control mechanism 23 ... Image acquisition mechanism 23a ... θ control unit 24 ... Conveying mechanism 25 ... CPU
25a ... Transport control unit 25b ... X-ray control unit 25c ... Stage control unit 25d ... Image acquisition unit 25e ... Pass / fail judgment unit 25f ... Height sensor control unit 28 ... Memory 28a ... Inspection object data 28b ... Imaging condition data 28c ... X-ray Image data 29 ... Height sensor control mechanism

Claims (7)

X-ray image acquisition means for irradiating X-rays onto an inspection target product on a substrate and acquiring a plurality of X-ray images taken from different directions;
Reconstruction operation means for performing a reconstruction operation based on the plurality of X-ray images;
A characteristic amount characteristic of the wiring pattern image of the board included in the reconfiguration information obtained by the reconfiguration operation is extracted from the reconfiguration information, and the inspection position of the inspection target product is determined based on the characteristic amount. An X-ray inspection apparatus comprising: a determining means for determining.   The determining means obtains a plurality of tomographic images in a direction parallel to the substrate and having different positions in a direction perpendicular to the substrate, and wiring of the substrate included in each tomographic image 2. The X-ray inspection apparatus according to claim 1, wherein a position of the wiring pattern in a direction perpendicular to the substrate is specified from pattern information, and the inspection position is determined. The X-ray inspection apparatus according to claim 1 , wherein the feature amount is edge information of an image.   The determination means according to any one of claims 1 to 3, wherein the brightness is a maximum when the brightness is scanned in a direction perpendicular to the substrate based on the reconstruction information. X-ray inspection apparatus according to the above.   5. The method according to claim 1, wherein the determining unit determines the inspection position based on information on a wiring pattern in a region where an influence of an artifact included in the reconstruction information is equal to or less than a predetermined value. X-ray inspection apparatus according to the above. An X-ray inspection method for inspecting an inspection object with X-rays,
An X-ray image acquisition step of acquiring a plurality of X-ray images taken from different directions by irradiating the inspection target product on the substrate with X-rays;
A reconstruction calculation step of performing a reconstruction calculation based on the plurality of X-ray images;
A characteristic amount characteristic of the wiring pattern image of the board included in the reconfiguration information obtained by the reconfiguration operation is extracted from the reconfiguration information, and the inspection position of the inspection target product is determined based on the characteristic amount. An X-ray inspection method comprising: a determining step for determining. An X-ray inspection program for inspecting an inspection object with X-rays,
An X-ray image acquisition function for acquiring a plurality of X-ray images taken from different directions by irradiating an inspection target product on a substrate with X-rays;
A reconstruction calculation function for performing a reconstruction calculation based on the plurality of X-ray images;
A characteristic amount characteristic of the wiring pattern image of the board included in the reconfiguration information obtained by the reconfiguration calculation is extracted from the reconfiguration information, and the inspection position of the inspection target product is determined based on the characteristic amount. An X-ray inspection program characterized by causing a computer to realize a determination function for determination.