Inspection equipment

Abstract

Provided is an inspection device for calculating a distance (height information) from a reference surface of an object to be inspected to a prescribed surface of a component attached to the object to be inspected, on the basis of three-dimensional image data of the object to be inspected.　A control unit 10 of an inspection device 1 executes: a first step for generating three-dimensional image data comprising a cross-sectional image of an object 12 to be inspected; a second step for extracting a prescribed number of cross-sectional image data from the prescribed reference surface; a third step for determining the position of a component (slave component 12d) in the extracted cross-sectional image data; a fourth step for calculating the amount of blurriness in the outline of the image of the slave component 12d in the extracted cross-sectional image data, and determining the position of a prescribed surface 12f of the slave component 12d; and a fifth step for calculating height information from the reference surface to the prescribed surface on the basis of the position of the reference surface and the position of the prescribed surface.

Description

Technical Field

[0001] The present invention relates to an inspection apparatus. Background Art

[0002] For an electronic substrate, the connection state between electronic components (e.g., pins) and wirings on the substrate formed by soldering (hereinafter referred to as "solder bonding state") is difficult to determine through visual inspection, so a tomosynthesis-type X-ray inspection apparatus is used (see, for example, Patent Document 1). Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Patent Application Laid-Open No. 61-114149 Summary of the Invention Problems to be Solved by the Invention

[0004] In recent years, among components arranged on electronic substrates, some components like SoC (System on Chip), MCM (Multi-Chip Module), and SiP (System in Package) have components such as chip components (hereinafter referred to as "child components") further mounted on the components themselves.

[0005] Figure 6 shows a case where a component 12b having a sub-component 12d (for example, the SoC described above) is mounted on the substrate 12a of the object under test 12. Such a component 12b is provided with solder balls 12c for electrical connection to the substrate 12a, and these solder balls 12c are soldered in the reflow process by paste solder applied to contacts on the upper surface (substrate inspection surface 12e) of the substrate 12a. Therefore, as shown in Figure 6, if the sub-component 12d is mounted on the back side of the component 12b, that is, between the substrate 12a and the component 12b, even if the sub-component 12d detaches from the component 12b due to the heat of the reflow process, it is difficult to check the mounting status of the sub-component 12d after the component 12b has been mounted on the substrate 12a.

[0006] The present invention has been made in view of these problems, and aims to provide an inspection device that can calculate the distance (height information) from a reference plane (for example, as shown in Figure 6, the substrate inspection surface 12e, which is the upper surface of the substrate 12a of the object to be inspected 12, is used as the reference plane) to a predetermined surface of a component attached to the object to be inspected (for example, the surface 12f of the sub-component 12d that faces the substrate inspection surface 12e) based on three-dimensional image data of the object to be inspected (reconstructed image data (cross-sectional image data) reconstructed from transmission image data). [Means for solving the problem]

[0007] To solve the aforementioned problems, the inspection apparatus according to the present invention comprises a radiation source, a holding unit for holding an object to be inspected to which a part to be measured is attached, a detector for detecting radiation from the radiation source that has passed through the object to be inspected and acquiring transmitted image data of the object to be inspected, and a control unit, wherein the control unit performs the following steps: a first step of generating three-dimensional image data composed of cross-sectional image data of the object to be inspected from the transmitted image data; a second step of extracting a predetermined number of cross-sectional image data in the direction in which the part is arranged from a predetermined reference plane; a third step of identifying the position of the part in the extracted cross-sectional image data; and a fourth step of calculating the amount of blurring of the outline of the image of the part in the selected cross-sectional image data based on the position of the part identified in the third step, identifying cross-sectional image data in which a predetermined surface of the part has been captured based on the amount of blurring, and determining the position of the identified cross-sectional image data as the position of the predetermined surface of the part. The aforementioned reference surface A fifth step is to calculate height information from the reference plane to the predetermined plane based on the position of the reference plane and the position of the predetermined plane determined in the fourth step. The fourth step involves: a 4-1 step in which, from the cross-sectional image data extracted in the second step, one cross-sectional image data is selected sequentially in the direction in which the part is positioned; a 4-2 step in which, based on the position of the part identified in the third step, the amount of blurring of the outline of the part's image in the cross-sectional image data selected in step 4-1 is calculated; a 4-3 step in which, if it is determined that the amount of blurring of the previously selected cross-sectional image data is greater than a predetermined threshold, and the amount of blurring of the currently selected cross-sectional image data has changed to a value less than or equal to a predetermined threshold, and if it is determined that it has not changed, the process returns to step 4-1 to select the next cross-sectional image data and repeats the subsequent processing; and a 4-4 step in which, if it is determined in step 4-3 that the value of the amount of blurring has changed, the currently selected cross-sectional image data is identified as cross-sectional image data in which a predetermined surface of the part has been captured, and the position of the identified cross-sectional image data is determined to be the position of the predetermined surface of the part. .

[0008] Furthermore, in the fourth step, the control unit of the inspection apparatus according to the present invention preferably calculates the distance from a pixel with a threshold value set as the lower limit to a pixel with a threshold value set as the upper limit, among the pixels in a predetermined range on a line that intersects a part of the outline, as the amount of blur.

[0009] Furthermore, in the fourth step, the control unit of the inspection apparatus according to the present invention determines the amount of blur as follows: The aforementioned external shape It is desirable to calculate the distance from the minimum value pixel to the maximum value pixel among the pixels in a predetermined range on a line that intersects a portion of the line.

[0010] Furthermore, in the third step, the control unit of the inspection apparatus according to the present invention preferably calculates the average value of the pixels at the same position for each pixel of the cross-sectional image data extracted in the second step, and determines the position of the part based on the average value of each pixel.

[0011] Furthermore, in the fourth step, the control unit of the inspection apparatus according to the present invention In the second step described above The extracted cross-sectional image data is taken from the reference plane side One by one in order Select the part, and based on the position of the part determined in the third step, calculate the amount of blurring of the outline of the part's image in the selected cross-sectional image data, and determine when the amount of blurring changes from a value greater than a predetermined threshold to a value less than or equal to a predetermined threshold. did It is desirable to determine the position of the cross-sectional image data at that time as the position of a predetermined surface of the part.

[0012] Furthermore, in the fourth step, the control unit of the inspection apparatus according to the present invention In the second step described above The extracted cross-sectional image data is taken from the side furthest from the reference plane. One by one in order Select the part, and based on the position of the part determined in the third step, calculate the amount of blurring of the outline of the part's image in the selected cross-sectional image data, and determine when the amount of blurring changes from a value greater than a predetermined threshold to a value less than or equal to a predetermined threshold. did It is desirable to determine the position of the cross-sectional image data at that time as the position of a predetermined surface of the part.

[0013] Furthermore, in the inspection apparatus according to the present invention, the control unit calculates the amount of blur at two or more locations on the outer shape of the part in the fourth step, identifies cross-sectional image data in which a predetermined surface of the part is captured at each location based on the amount of blur at each location, and determines the position of the identified cross-sectional image data as the position of the predetermined surface of the part at each location. In the fifth step, based on the position of the reference surface and the positions of the predetermined surfaces at each of the two or more locations determined in the fourth step, it is desirable to calculate height information from the reference surface to the predetermined surface at each location, and further calculate inclination information of the predetermined surface based on the height information of the two or more locations. [Effects of the Invention]

[0014] According to the inspection apparatus of the present invention, the distance (height information) from a reference surface (e.g., a substrate inspection surface) to a predetermined surface of a component attached to an object to be inspected can be calculated based on three-dimensional image data of the object to be inspected (reconstructed image data (cross-sectional image data) reconstructed from transmission image data). [BRIEF DESCRIPTION OF THE DRAWINGS]

[0015] [Figure 1] It is an explanatory diagram for explaining the configuration of an inspection apparatus according to an embodiment of the present invention. [Figure 2] It is an explanatory diagram for explaining each functional block of a control unit of the inspection apparatus. [Figure 3] It is a flowchart for explaining inspection processing in the inspection apparatus. [Figure 4] It is a flowchart for explaining solder bonding state determination processing among determination processing in inspection processing. [Figure 5] It is a flowchart for explaining height information calculation processing among determination processing in inspection processing. [Figure 6] It is an explanatory diagram for explaining height information calculation processing for a predetermined surface of a component attached to a substrate of an object to be inspected (a surface of a child component facing the substrate surface). [Figure 7] It is an explanatory diagram for explaining the shape of an image of a child component in three-dimensional image data, in which (a) shows the irradiation direction of radiation emitted from a radiation generator onto the child component, and (b) shows the shape of the image of the child component. [Figure 8] It is an explanatory diagram showing a cross-sectional image of a child component, in which (a) shows a cross-sectional image in a real image region, and (b) shows a cross-sectional image in a virtual image region. [Figure 9] It is an explanatory diagram for calculating tilt information of a predetermined surface of a component attached to a substrate of an object to be inspected (a surface of a child component facing the substrate surface), in which (a) shows a tilted child component, and (b) shows a plurality of locations for calculating a width (blur amount) for tilt information. [Figure 10] It is an explanatory diagram for explaining a modification of the height information calculation processing. DESCRIPTION OF EMBODIMENTS

[0016] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, an inspection apparatus 1 according to the present embodiment includes a control unit 10 configured by a processing apparatus such as a personal computer (PC), a monitor 11, and an imaging unit 32. The imaging unit 32 includes a radiation generator 22, a substrate holding unit 24, a detector 26, a radiation quality changing unit 14, a radiation generator driving unit 16, a substrate holding unit driving unit 18, and a detector driving unit 20.

[0017] The radiation generator 22 is an apparatus (radiation source) that generates radiation such as X-rays, and generates radiation by, for example, causing accelerated electrons to collide with a target such as tungsten or diamond. In the present embodiment, the case where the radiation is X-rays will be described, but the radiation is not limited thereto. For example, the radiation may be alpha rays, beta rays, gamma rays, ultraviolet rays, visible light, or infrared rays. The radiation may also be microwaves or terahertz waves.

[0018] The substrate holding unit 24 holds an electronic substrate that is the object 12 to be inspected (hereinafter simply referred to as "substrate"). The radiation generated by the radiation generator 22 is irradiated onto the inspection object 12 held by the substrate holding unit 24, and the radiation transmitted through the inspection object 12 is detected by the detector 26 and captured as an image. Hereinafter, the radiation transmission image of the inspection object 12 captured by the detector 26 is referred to as a "transmission image". As will be described later, in the present embodiment, the substrate holding unit 24 holding the substrate as the inspection object 12 and the detector 26 are relatively moved with respect to the radiation generator 22 to acquire a plurality of transmission images, and a reconstructed image (cross-sectional image), which is a three-dimensional image, is generated from these transmission images.

[0019] The transmission image captured by the detector 26 (transmission image data, which is the transmission image data output from the detector 26) is sent to the control unit 10 and reconstructed into image data including the three-dimensional shape of the solder joint using known techniques such as the filtered-backprojection method (FBP method). The reconstructed image data and transmission image data are then stored in the storage within the control unit 10 (for example, the memory unit 34 described later) or in external storage (not shown). Hereinafter, image data extracted from one cross-section of the three-dimensional shape calculated based on the transmission image data will be called a cross-sectional image (cross-sectional image data). A set of one or more cross-sectional image data will be called "3D image data" or "reconstructed image data". In other words, cross-sectional image data is image data obtained by cutting out an arbitrary cross-section from the reconstructed image data. Such reconstructed images and cross-sectional images are output to the monitor 11. The monitor 11 displays not only the reconstructed images and cross-sectional images, but also the inspection results of the solder joint state, which will be described later. Here, the reconstructed image in this embodiment is also called "planar CT" because, as described above, it is reconstructed from a planar image (transmission image data) captured by the detector 26.

[0020] The radiation quality changing unit 14 changes the quality of the radiation generated by the radiation generator 22. The quality of the radiation is determined by the voltage applied to accelerate the electrons that collide with the target (hereinafter referred to as "tube voltage") and the current that determines the number of electrons (hereinafter referred to as "tube current"). The radiation quality changing unit 14 is a device that controls these tube voltage and tube current. This radiation quality changing unit 14 can be realized using known technologies such as transformers and rectifiers.

[0021] Here, the quality of radiation is determined by its brightness and hardness (spectral distribution). Increasing the tube current increases the number of electrons that collide with the target, and thus the number of photons produced. As a result, the brightness of the radiation increases. For example, some components, such as capacitors, are thicker than other components, and to capture transmission images of these components, it is necessary to irradiate them with high-brightness radiation. In such cases, the brightness of the radiation is adjusted by adjusting the tube current. Also, increasing the tube voltage increases the energy of the electrons that collide with the target, and thus the energy (spectrum) of the produced radiation increases. Generally, the higher the energy of the radiation, the greater its penetrating power through materials and the less easily it is absorbed by those materials. Transmission images captured using such radiation have low contrast. Therefore, the tube voltage can be used to adjust the contrast of the transmission image.

[0022] The radiation generator drive unit 16 has a drive mechanism such as a motor (not shown) that can move the radiation generator 22 up and down along axis A (the axis (optical axis) passing through the center of the radiation direction of the radiation emitted from the radiation generator 22, and the direction of this axis is defined as the "Z-axis direction") that passes through its focal point. This makes it possible to change the irradiation field by changing the distance between the radiation generator 22 and the object to be inspected (substrate) 12 held by the substrate holding unit 24, and to change the magnification of the transmitted image captured by the detector 26. The position of the radiation generator 22 in the Z-axis direction is detected by the generator position detection unit 23 and output to the control unit 10.

[0023] The detector drive unit 20 also has a drive mechanism such as a motor (not shown) that rotates the detector 26 along the detector rotation trajectory 30. The substrate holder drive unit 18 also has a drive mechanism such as a motor (not shown) that moves the substrate holder 24 in parallel on a plane on which the substrate rotation trajectory 28 is provided. The substrate holder 24 is configured to rotate along the substrate rotation trajectory 28 in conjunction with the rotational movement of the detector 26. This makes it possible to capture multiple transmission images with different projection directions and projection angles while changing the relative positional relationship between the object under inspection 12 held by the substrate holder 24 and the radiation generator 22. In this embodiment of the inspection apparatus 1, the area on which a transmission image can be acquired on the object under inspection 12 is determined by the size of the radiation detection area of ​​the detector 26 and the relative positions of the radiation generator 22, the object under inspection 12 (substrate holder 24), and the detector 26. This area on which a transmission image can be acquired (imaging area) is called the "FOV (field of view)".

[0024] The rotation radii of the substrate rotation trajectory 28 and the detector rotation trajectory 30 are not fixed but can be freely changed. This makes it possible to arbitrarily change the irradiation angle of the radiation irradiated onto the substrate, which is the object under inspection 12, and the components attached to this substrate. The orbital planes of the substrate rotation trajectory 28 and the detector rotation trajectory 30 are perpendicular to the Z-axis direction as described above. If the directions perpendicular to these orbital planes are considered to be the X-axis direction and the Y-axis direction, the positions of the substrate holding unit 24 in the X-axis direction and the Y-axis direction are detected by the substrate position detection unit 29 and output to the control unit 10, and the positions of the detector 26 in the X-axis direction and the Y-axis direction are detected by the detector position detection unit 31 and output to the control unit 10.

[0025] The control unit 10 controls all operations of the inspection device 1 described above. The main functions of the control unit 10 will be explained below with reference to Figure 2. Although not shown, input devices such as a keyboard and mouse are connected to the control unit 10.

[0026] The control unit 10 includes a storage unit 34, an imaging processing unit 35, a cross-sectional image generation unit 36, a substrate inspection surface detection unit 38, a pseudo-cross-sectional image generation unit 40, and an inspection unit 42. Although not shown, the imaging processing unit 35 of the control unit 10 also has the function of an imaging control unit that controls the operation of the beam quality changing unit 14, the radiation generator drive unit 16, the substrate holding unit drive unit 18, and the detector drive unit 20. Furthermore, each of these functional blocks is realized through the cooperation of hardware such as a CPU that performs various calculations, RAM used as a work area for data storage and program execution, and software. Therefore, these functional blocks can be realized in various forms by combinations of hardware and software.

[0027] The memory unit 34 stores information such as imaging conditions for capturing a transmission image of the substrate, which is the object under inspection 12, and the design of the substrate. The memory unit 34 also stores image data such as the transmission image and reconstructed image (cross-sectional image, pseudo-cross-sectional image) of the substrate, as well as the inspection results of the inspection unit 42, which will be described later. The memory unit 34 also stores information for driving the radiation generator drive unit 16, the substrate holding unit drive unit 18, and the detector drive unit 20 (for example, the speed at which the radiation generator drive unit 16 drives the radiation generator 22, the speed at which the substrate holding unit drive unit 18 drives the substrate holding unit 24, and the speed at which the detector drive unit 20 drives the detector 26, etc.).

[0028] The imaging processing unit 35 drives the radiation generator 22, substrate holder 24, and detector 26 using the radiation generator drive unit 16, substrate holder drive unit 18, and detector drive unit 20 to image the object under inspection 12 held by the substrate holder 24, acquire transmission image data, and generate reconstructed image data (cross-sectional image data) from the transmission image data. The method of acquiring transmission image data (imaging of transmission images) and generating reconstructed image data (cross-sectional image data) by the imaging processing unit 35 will be described later.

[0029] The cross-sectional image generation unit 36 ​​generates reconstructed image data (cross-sectional image data) based on multiple transparent image data acquired from the storage unit 34. This can be achieved using known techniques such as the FBP method or the maximum likelihood estimation method. Different reconstruction algorithms result in different properties of the reconstructed image data and different reconstruction times. Therefore, it is possible to prepare multiple reconstruction algorithms and the parameters used in each algorithm in advance and allow the user to select one. This provides the user with the freedom to choose, such as prioritizing a shorter reconstruction time or prioritizing high image quality even if it takes longer. Each of the generated cross-sectional image data is stored in the storage unit 34 along with attribute information such as the position in the Z-axis direction of each cross-sectional image data and the position (coordinate) of pixels in the X-axis and Y-axis directions within the cross-sectional image data.

[0030] The substrate inspection surface detection unit 38 identifies, from among multiple cross-sectional image data generated by the cross-sectional image generation unit 36, the image data (cross-sectional image data) that shows the surface on the substrate to be inspected (for example, the top surface of the substrate, which is called the "substrate inspection surface") on the substrate 12 to be inspected. Hereafter, the cross-sectional image (cross-sectional image data) that shows the substrate inspection surface of the substrate will be called the "inspection surface image (inspection surface image data)".

[0031] The pseudo-cross-sectional image generation unit 40 visualizes a region of the substrate thicker than the cross-sectional image by stacking a predetermined number of consecutive cross-sectional images (cross-sectional image data) from the cross-sectional image data generated by the cross-sectional image generation unit 36. The number of cross-sectional images to stack is determined by the thickness of the substrate region shown by the cross-sectional image (hereinafter referred to as "slice thickness") and the slice thickness of the pseudo-cross-sectional image. For example, if the slice thickness of the cross-sectional image is 50 μm, and the slice thickness of the pseudo-cross-sectional image is to be the height of a BGA solder ball (hereinafter simply referred to as "solder") (for example, 500 μm), then 500 / 50 = 10 cross-sectional images should be stacked. In this case, the inspection surface image data identified by the substrate inspection surface detection unit 38 is used to identify the position of the solder.

[0032] The inspection unit 42 is configured to perform various control processes for inspection based on the substrate inspection data stored in the memory unit 34, using the cross-sectional image data generated by the cross-sectional image generation unit 36, the inspection surface image data identified by the substrate inspection surface detection unit 38, and the pseudo-cross-sectional image data generated by the pseudo-cross-sectional image generation unit 40. Here, the substrate inspection data is inspection data created for each type of substrate. An inspection area (hereinafter referred to as "inspection window") is set for each location on the image data of the object to be inspected 12 to be inspected, and the inspection data consists of inspection items set for each inspection window and inspection criteria that serve as the basis for determining whether the item is good or bad. One or more inspection windows are set for each inspection item. For example, in an inspection item that determines whether the solder application state is good or bad, usually the same number of inspection windows as the number of solder application areas of the component are set in an arrangement corresponding to the arrangement of the solder application areas. In addition, for inspection items that use image data of the object to be inspected 12 that has undergone predetermined image processing, the content of that image processing is also included in the inspection data.

[0033] The inspection unit 42 inspects the solder joint condition. Since the solder that joins the substrate and the component is located near the substrate inspection surface, it is possible to determine whether the solder is properly joining the substrate and the component by inspecting the inspection surface image data and the cross-sectional image data that shows the area on the radiation generator 22 side relative to the inspection surface image data.

[0034] Here, "solder joint condition" refers to whether the substrate and the component are joined by solder and whether an appropriate conductive path is created. Inspection of the solder joint condition includes bridge inspection, molten state inspection, and void inspection. "Bridge" refers to an undesirable conductive path between conductors created by the solder joint. "Molten state" refers to whether the joint between the substrate and the component is insufficient due to insufficient solder melting, also known as "floating." "Void" refers to a defect in the solder joint caused by air bubbles within the solder joint. Therefore, the inspection unit 42 includes a bridge inspection unit 44, a molten state inspection unit 46, and a void inspection unit 48.

[0035] The detailed operation of the bridge inspection unit 44, the molten state inspection unit 46, and the void inspection unit 48 will be described later, but the bridge inspection unit 44 and the void inspection unit 48 inspect bridges and voids, respectively, based on pseudo-cross-sectional image data generated by the pseudo-cross-sectional image generation unit 40, and the molten state inspection unit 46 inspects the molten state of the solder based on inspection surface image data identified by the substrate inspection surface detection unit 38. The inspection results from the bridge inspection unit 44, the molten state inspection unit 46, and the void inspection unit 48 are stored in the storage unit 34.

[0036] Furthermore, the inspection unit 42 has a height information calculation unit 50 that calculates height information for a predetermined surface of a component attached to the object under inspection 12 based on cross-sectional image data and pseudo-cross-sectional image data, including inspection surface image data. For this purpose, the substrate inspection data is set up with an inspection window that is arranged to include a predetermined surface of the component from which height information is to be acquired (the sub-component 12d described above). The height information calculated by the height information calculation unit 50 is stored in the storage unit 34.

[0037] Figures 3 to 5 are flowcharts illustrating the process from capturing transmission images (acquiring transmission image data) and generating reconstructed image data (cross-sectional image data), to identifying inspection surface image data, generating pseudo-cross-sectional images, and performing inspection (acquiring solder joint status and height information). The process in this flowchart starts, for example, when the control unit 10 receives an instruction to start inspection from an input device (not shown).

[0038] As shown in Figure 3, when the control unit 10 loads the object to be inspected 12 into the inspection device 1 and the inspection begins, the imaging processing unit 35 of the control unit 10 sets the irradiation field of the radiation emitted from the radiation generator 22 by the radiation generator drive unit 16 (the imaging area to which radiation is irradiated in order to acquire the transmission image data of the field of view FOV described above) (step S100), and starts the image acquisition and judgment process. If there are multiple imaging areas (FOVs) on the object to be inspected 12, the imaging areas (FOVs) are selected and set in a predetermined order.

[0039] When the image acquisition and judgment process is started, the imaging processing unit 35 of the control unit 10 executes transmission image acquisition and reconstruction image generation processing, imaging the object under inspection 12 to acquire transmission image data, and generating reconstruction image data using that transmission image data (step S102). Specifically, in the transmission image acquisition and reconstruction image generation process S102, the imaging processing unit 35 of the control unit 10 moves the substrate holder 24 with the substrate holder drive unit 18 and moves the detector 26 with the detector drive unit 20 to change the imaging position, while setting the beam quality of the radiation generator 22 with the beam quality change unit 14, and irradiating the current imaging area (FOV) of the object under inspection 12 with radiation to acquire transmission image data and store it in the storage unit 34. In addition, the cross-sectional image generation unit 36 ​​of the control unit 10 reads multiple transmission image data from the storage unit 34, generates reconstruction image data (cross-sectional image data) using that transmission image data, and stores it in the storage unit 34.

[0040] The movement paths of the substrate holder 24 by the substrate holder drive unit 18 and the detector 26 by the detector drive unit 20 when acquiring transmission image data are pre-set in the substrate holder drive unit 18 and the detector drive unit 20 by reading information stored in the storage unit 34 or by inputting from an input device. The position of the radiation generator 22 in the Z-axis direction is also pre-set in the radiation generator drive unit 16 by the same method. In this case as well, the substrate holder 24 and the detector 26 may be moved to the desired position by the substrate holder drive unit 18 and the detector drive unit 20, and the transmission image data may be acquired after stopping the substrate holder 24 and the detector 26 at the position where the transmission image data is to be acquired, or the transmission image data may be acquired at the desired position while moving the substrate holder 24 and the detector 26 by the substrate holder drive unit 18 and the detector drive unit 20. The acquired transmission image data is stored in the storage unit 34 for each imaging field of view (FOV).

[0041] The substrate inspection surface detection unit 38 of the control unit 10 receives transmission image data or reconstructed image data (cross-sectional image data) from the cross-sectional image generation unit 36 ​​and performs a substrate inspection surface detection and pseudo-cross-sectional image generation process to identify the inspection surface image from among them (step S104). Here, the storage unit 34 has in advance stored cross-sectional image data of the substrate inspection surface of a normal object to be inspected 12 that has no abnormalities in the solder joint state, etc. (this is called "reference image data"). In the substrate inspection surface detection and pseudo-cross-sectional image generation process S104, the substrate inspection surface detection unit 38 of the control unit 10 compares the reference image data with each of the cross-sectional image data generated in step S102, identifies the cross-sectional image data that best matches the reference image data as the inspection surface image data, stores the identified cross-sectional image data (inspection surface image data) in the storage unit 34, and stores its position in the Z-axis direction as the position of the substrate inspection surface in the current field of view (FOV) in the storage unit 34. As a method for identifying the cross-sectional image data that best matches the reference image data from among the cross-sectional image data, for example, the phase-limited correlation method can be used to quickly determine the matching rate regardless of positional misalignment. Furthermore, the pseudo-cross-sectional image generation unit 40 of the control unit 10 generates pseudo-cross-sectional image data based on the identified inspection surface image data and the position of the substrate inspection surface in the Z-axis direction, and stores it in the storage unit 34.

[0042] In this process, multiple cross-sectional image data are generated as reconstructed image data from transparent image data, and a reference image data is determined and pseudo-cross-sectional image data is generated for these cross-sectional image data. However, it is also possible to perform the process of determining the reference image data and generating pseudo-cross-sectional image data each time a cross-sectional image data is generated as reconstructed image data, and then generating the next cross-sectional image data.

[0043] Next, the inspection unit 42 of the control unit 10 selects one of the inspection windows set in the current imaging area (FOV) (step S106) and executes the judgment process (inspection) set in that inspection window (step S108). The specific details of the judgment process will be described later. When the judgment process for the currently selected inspection window is completed, the inspection unit 42 of the control unit 10 determines whether there is another inspection window (step S110). If it determines that there is another inspection window (step S110:Y), it returns to step S106 to select the next inspection window and repeats the judgment process. On the other hand, if the inspection unit 42 of the control unit 10 determines that it has executed the judgment process for all inspection windows (step S110:N), the imaging processing unit 35 of the control unit 10 determines whether there is another imaging area (FOV) (step S112). If it determines that there is another imaging area (step S112:Y), it returns to step S100 to select the next imaging area (FOV) and repeats the image acquisition and judgment process. On the other hand, if the imaging processing unit 35 of the control unit 10 determines that there is no next imaging area (FOV) (step S112:N), it terminates the inspection process and the control unit 10 removes the object to be inspected 12 from the inspection device 1.

[0044] As mentioned above, image acquisition and judgment processing may be performed for each imaging field of view (FOV), or the inspection may be performed sequentially for each imaging field of view (FOV) after the generation of reconstructed image data (cross-sectional image data and pseudo-cross-sectional image data) has been completed, in parallel with the acquisition of transmission image data and generation of reconstructed image data for other imaging fields (FOVs).

[0045] Now, let's explain the specific details of the judgment process. Here, as an example of the judgment process, we will explain the solder joint state determination process and the height information calculation process for a predetermined surface of a component attached to the object to be inspected 12.

[0046] (Solder joint condition determination process) In the determination process S108 described above, if the inspection unit 42 determines that the inspection in the currently selected inspection window is an inspection of the solder joint state, the inspection unit 42 of the control unit 10 executes the joint state determination process shown in Figure 4 for the currently selected inspection window.

[0047] First, the bridge inspection unit 44 of the control unit 10 acquires a pseudo-cross-sectional image from the pseudo-cross-sectional image generation unit 40 with a slice thickness similar to that of the solder ball (read from the storage unit 34), and checks for the presence or absence of a bridge within the currently selected inspection window (step S200). If no bridge is detected (step S202:N), the melting state inspection unit 46 of the control unit 10 acquires an inspection surface image from the substrate inspection surface detection unit 38 (read from the storage unit 34), and checks whether the solder is melted within the currently selected inspection window (step S204). If the solder is melted (step S206:Y), the void inspection unit 48 of the control unit 10 acquires a pseudo-cross-sectional image from the pseudo-cross-sectional image generation unit 40 that partially shows the solder ball (read from the storage unit 34), and checks whether voids exist within the currently selected inspection window (step S208). If no voids are found (step S210:N), the inspection unit 42 of the control unit 10 determines that the solder joint is normal and outputs this to the storage unit 34 (step S212). If a bridge is detected (step S202:Y), if the solder is not molten (step S206:N), or if voids are present (step S210:Y), the inspection unit 42 determines that the solder joint is abnormal and outputs this to the storage unit 34 (step S214). Once the solder state is output to the storage unit 34, the joint state determination process in this flowchart is terminated. Note that bridge inspection, molten state inspection, and void inspection may be performed in parallel.

[0048] (Height information calculation process) As explained using Figure 6, in order to check the mounting status of the sub-component 12d on a component 12b that has a sub-component 12d, the upper surface of the substrate 12a (the substrate inspection surface described above) 12e is used as a reference surface (reference surface) on the component 12b attached to the substrate 12a, and the distance in the Z-axis direction (height information H) between this reference surface and the surface of the sub-component 12d facing the substrate 12a (in Figure 6, the lower surface of the sub-component 12d, which is the predetermined surface described above) 12f is measured, and based on this height information H, it is possible to determine whether or not the sub-component 12d is correctly mounted on the component 12b. First, the method for calculating the height information H from the substrate inspection surface 12e of the substrate 12a to the surface 12f of the sub-component 12d facing the substrate 12a will be explained in the inspection apparatus 1 according to this embodiment.

[0049] As described above, in the inspection apparatus 1 according to this embodiment, the object to be inspected 12 (substrate holding part 24) and the detector 26 are moved relative to the radiation generator 22 to acquire transmission image data of the object to be inspected 12. Therefore, as shown in Figure 7(a), transmission image data is acquired in which radiation is irradiated from an oblique direction onto the part 12b and sub-part 12d. When three-dimensional image data (reconstructed image data or cross-sectional image data) is generated from such transmission image data, the image I of the sub-part 12d in this three-dimensional image data takes on a shape that extends in the Z-axis direction, as shown in Figure 7(b). Here, the part of the image I that represents the image of the sub-part 12d is called the real image region Rr, and the part formed by reconstruction is called the virtual image region Rv.

[0050] Figure 8 shows cross-sectional images I of the sub-part 12d within the inspection window W for inspecting the sub-part 12d. Each cross-sectional image shows the change in brightness value of pixels on a line L extending from the center of the sub-part 12d in a direction approximately perpendicular to the long side of the sub-part 12d. As shown in Figure 8(a), the cross-sectional image Ir in the real image region Rr is clearly visible, while as shown in Figure 8(b), the cross-sectional image Iv in the virtual image region Rv is blurred. Specifically, in the cross-sectional image Ir in the real image region Rr, the brightness value changes rapidly at the outline of the sub-part 12d (hereinafter referred to as the "edge"), while in the cross-sectional image Iv in the virtual image region Rv, the change in brightness value is gradual. Therefore, in this embodiment, for each cross-sectional image, the amount of blur at the edge of the image I of the sub-component 12d (the degree of variation in the change in brightness value at the edge) is calculated, and the boundary between the virtual image region Rv and the real image region Rr of the sub-component 12d is determined by this amount of blur, and the position of that boundary is determined to be the surface 12f of the sub-component 12d facing the substrate 12a. In the case of a sub-component 12d with a rectangular cross-sectional shape, since objects with irregular shapes, such as solder, are often formed on the short side, it is preferable to calculate the amount of blur (change in brightness value) at the edge on the long side. If the amount of blur on the short side is clear depending on the object, it may be calculated at the edge on the short side.

[0051] The amount of blur is calculated as the width D, which is the distance from the pixel with a threshold set as the lower limit to the pixel with a threshold set as the upper limit, among the changes in brightness value at the edges of the image I(Ir,Iv) of the sub-component 12d. In the case of Figure 8, the width D is the distance from the pixel whose brightness value exceeds or reaches the lower limit to the pixel just before exceeding or reaching the upper limit, in the direction of the arrow of line L. Here, the width D may be expressed in terms of the number of pixels, or it may be expressed by converting the pixel pitch to a length (mm, etc.). As is clear from Figure 8, the width (amount of blur) Dr in the real image region Rr is smaller than the width (amount of blur) Dv in the virtual image region Rv. Therefore, the value of the width (amount of blur) D in the cross-sectional image where the virtual image region Rv and the real image region Rr switch is set as a threshold, and the position of the cross-sectional image data when the width D changes from a width D greater than the threshold to a width D less than or equal to the threshold, as viewed from the reference surface side, is determined to be the position of the surface 12f of the sub-component 12d facing the substrate 12a.

[0052] Alternatively, the blur amount, width D, may be defined as the distance between the pixel with the minimum brightness value and the pixel with the maximum brightness value on the line L described above. In this case, if there are multiple pixels with the minimum brightness value, the outermost pixel (the one furthest from the center of the child component 12d) may be defined as the minimum value pixel, and if there are multiple pixels with the maximum brightness value, the innermost pixel (the one closest to the center of the child component 12d) may be defined as the maximum value pixel. As shown in Figure 8(a), since the boundary (outline) of the child component 12d is emphasized in the reconstructed image (cross-sectional image), the minimum and maximum value pixels (the blackest pixel and the whitest pixel) are effectively located near the boundary, and by defining the blur amount as the distance (width D) between the maximum and minimum value pixels, the calculation of the blur amount (width D) becomes easier. Furthermore, by calculating the blur amount as the interval (width D) between the maximum and minimum pixels, the calculation of width D becomes less susceptible to changes in brightness values ​​in each cross-sectional image data. This improves the accuracy of determining the boundary between the virtual image region Rv and the real image region Rr based on this blur amount (width D), that is, determining the position of the surface 12f of the sub-component 12d facing the substrate 12a.

[0053] In a typical inspected object (substrate) 12, the distance from the top surface of the substrate 12a (substrate inspection surface 12e) to the surface 12f of the sub-component 12d facing the substrate 12a is approximately 300 μm. Therefore, if the slice thickness of the cross-sectional image is 10 μm, height information can be obtained by stacking 300 / 10 = 30 cross-sectional images using the method described above. In other words, the pseudo-cross-sectional image generation unit 40 can generate pseudo-cross-sectional image data by extracting approximately 30 cross-sectional image data with a slice thickness of 10 μm from the substrate inspection surface 12e towards the radiation generator 22. Note that the above explanation is just one example, and the number of cross-sectional image data images that make up the pseudo-cross-sectional image data will be determined according to the distance from the top surface of the substrate 12a to the surface 12f of the sub-component 12d facing the substrate 12a and the slice thickness.

[0054] Next, we will explain the specific processing performed by the control unit 10 for calculating height information. In the determination process S108 described above, if the inspection unit 42 determines that the inspection in the currently selected inspection window is the calculation of height information for a predetermined surface of the component 12b attached to the object under inspection 12 (the surface (bottom surface) 12f of the sub-component 12d, which is attached to the substrate 12a side of the component 12b and positioned to face the substrate inspection surface 12e), the inspection unit 42 of the control unit 10 executes the height information calculation process shown in Figure 5 for the currently selected inspection window. It is assumed that a cross-sectional image of the sub-component 12d is captured in the currently selected inspection window W.

[0055] The height information calculation unit 50 of the control unit 10 identifies the position of a predetermined surface within the currently selected inspection window W, i.e., the position of the sub-component 12d (step S300). The inspection window W is set at the same position on the substrate in multiple cross-sectional image data that constitute the pseudo-cross-sectional image data. Therefore, here, for each pixel within the inspection window W, the average value of the same pixel in all the cross-sectional image data that constitute the pseudo-cross-sectional image data generated in step S104 is calculated, and then a binarization process is performed on each average value (for example, pixels with a value greater than a predetermined threshold are set to the maximum value, and pixels with a value less than or equal to the predetermined threshold are set to the minimum value). This process makes it easy to identify the position of the sub-component 12d because the pixel value at the position where the sub-component 12d is imaged becomes the minimum value (black). Then, the height information calculation unit 50 of the control unit 10 determines the center of the sub-part 12d (the centroid of the pixel set to the minimum value) based on the position of the sub-part 12d identified in step S300 (in the current inspection window W, the pixel set to the minimum value (black pixel) is the image of the sub-part 12d) (step S302).

[0056] Next, the height information calculation unit 50 of the control unit 10 selects one cross-sectional image data from the pseudo-cross-sectional image data (step S304). Here, we will explain the case where cross-sectional image data is selected from the reference image data side (the substrate inspection surface 12e side, which is the reference surface) toward the radiation generator 22 side. Within the currently selected inspection window in the selected cross-sectional image data, the height information calculation unit 50 of the control unit 10 calculates the above-mentioned width (blur amount) D using the pixel values ​​(luminance values) in a predetermined range on a line L that intersects (is approximately perpendicular to) the edge (for example, the long side edge) of the sub-component 12d (for example, the long side edge) of the sub-component 12d, from the center of the sub-component 12d determined in step S302 toward the outer circumference of the inspection window W (step S306).

[0057] The height information calculation unit 50 of the control unit 10 selects the next cross-sectional image data (step S308). Here, we will describe the case in which, from among the pseudo-cross-sectional image data, the cross-sectional image data adjacent to the radiation generator 22 side of the currently selected cross-sectional image data is selected as the next cross-sectional image data. The height information calculation unit 50 of the control unit 10 calculates the width (blur amount) D of the currently selected inspection window W at the same position (line L intersecting the edge) as the previous cross-sectional image (step S310). Then, the height information calculation unit 50 of the control unit 10 determines whether or not the blur amount D satisfies predetermined judgment conditions (step S312). Specifically, the amount of blur in the currently selected cross-sectional image data (the amount of blur calculated in step S310) is compared with the amount of blur in the cross-sectional image data adjacent to the reference surface side (substrate inspection surface 12e side) of this cross-sectional image data (the previous cross-sectional image data) (the amount of blur calculated in step S306). When the amount of blur in the previous cross-sectional image data is greater than a predetermined threshold, and the amount of blur in the currently selected cross-sectional image data changes to a value less than or equal to the predetermined threshold, it is determined that the predetermined judgment conditions are satisfied.

[0058] If the height information calculation unit 50 of the control unit 10 determines that the amount of blur does not satisfy the predetermined judgment conditions (step S312:N), it returns to step S308, selects the next cross-sectional image data, and repeats the subsequent processing. On the other hand, if the height information calculation unit 50 of the control unit 10 determines that the amount of blur satisfies the predetermined judgment conditions (step S312:Y), it determines the position of the currently selected cross-sectional image data (position in the Z-axis direction) as the position of the surface 12f of the sub-component 12d facing the substrate 12a (a predetermined surface of component 12b) (step S314), calculates the height information H of the predetermined surface 12f in the currently selected inspection window from the position in the Z-axis direction of the reference image data (cross-sectional image data of the substrate inspection surface), which is the reference surface (step S316), and terminates the height information calculation process.

[0059] In the above explanation, we described a case where the amount of blur is calculated by sequentially selecting the cross-sectional image data constituting the pseudo-cross-sectional image data from the reference surface side (substrate inspection surface 12e side), and comparing the amount of blur of the currently selected cross-sectional image data with the amount of blur of the previous cross-sectional image data (cross-sectional image data adjacent to the substrate inspection surface 12e side of the currently selected cross-sectional image data) to determine the position in the Z-axis direction of a predetermined surface 12f of component 12b (the surface facing the substrate surface side of sub-component 12d). However, the above blur amount determination process may also be performed sequentially from the cross-sectional image data with a specific offset from the reference surface (reference image data) among the cross-sectional image data constituting the pseudo-cross-sectional image data, or a binary search may be performed based on the position of the reference surface (reference image data) and the offset position to determine the blur amount.

[0060] Furthermore, in the above explanation, the substrate inspection surface 12e was used as the reference surface for calculating height information, but the reference surface may be set at other locations (for example, the back surface of the substrate 12a or a predetermined surface of the substrate holding part 24 that holds the substrate 12a).

[0061] By using this height information determination process, the height information of a predetermined surface (the surface of the sub-component 12d facing the substrate 12a) 12f of component 12b can be calculated using pseudo-cross-sectional image data used in the solder joint state determination process. In this case, since it is not necessary to input information on the size of the sub-component 12d (for example, the length of the edge of the surface 12f facing the substrate 12a), the height information can be calculated without depending on variations in the manufacturing of the sub-component 12d (for example, a chip). It is also possible to calculate the area of ​​the cross-sectional image of the sub-component 12d for each cross-sectional image data that makes up the pseudo-cross-sectional image data and determine the boundary between the virtual image region Rv and the real image region Rr, but since the edges of the cross-sectional image Iv of the sub-component 12d in the virtual image region Rv are blurred (not clear), it is not easy to calculate the area from the brightness value of the pixels.

[0062] (Calculation of tilt information of sub-components) By using the height information determination process according to this embodiment, it is also possible to calculate the inclination information of the predetermined surface (sub-component 12d) described above. As described above, if a part of the sub-component 12d detaches from the component 12b during a reflow process or the like, the surface 12f of the sub-component 12d facing the substrate 12a may become inclined, as shown in Figure 9(a). Therefore, in the sub-component 12d within the inspection window W, height information can be calculated from the amount of blur at least two locations, and the inclination information of the sub-component 12d can be calculated from this height information. Specifically, as shown in Figure 9(b), the width of the edge (amount of blur) is calculated from the brightness value of the pixels on a line L0 extending from the center of the sub-component 12d in a direction approximately perpendicular to the long side of the sub-component 12d to determine the height information H0, and the width of the edge (amount of blur) on a line different from this line L0 is calculated to determine the height information, thereby calculating the inclination information of the surface 12f of the sub-component 12d facing the substrate surface. In the example shown in Figure 9, the width (blur amount) of the edges of two lines L1 and L2 located in the long-side direction with the center of the sub-component 12d is calculated to determine the height information H1 and H2 for each, and the tilt information of the sub-component 12d (tilt information of the surface 12f of the sub-component 12d facing the substrate surface) is calculated using this height information H0, H1, and H2.

[0063] When calculating such inclination information, the height information calculation unit 50 of the control unit 10 calculates the width (blur amount) of multiple locations (for example, three locations, lines L0, L1, and L2 in Figure 9) within the inspection window of the currently selected cross-sectional image data in step S306 during the height information calculation process shown in Figure 5. The height information calculation unit 50 of the control unit 10 also calculates the width (blur amount) of multiple locations within the inspection window of the currently selected cross-sectional image data in step S310. Then, in step S312, the height information calculation unit 50 of the control unit 10 determines whether the blur amount of each location satisfies the judgment condition. For locations that satisfy the judgment condition, it stores the location and the position of the cross-sectional image data when the judgment condition was satisfied, and returns to step S308 to repeat the process until all locations satisfy the judgment condition. Then, when the height information calculation unit 50 of the control unit 10 determines that the judgment conditions have been met at all locations, in step S316, it calculates the height information for each location (for example, in the case of Figure 9, height information H0, H1, H2) from the position of the cross-sectional image data that satisfies the judgment conditions for each location, and calculates the inclination information of the sub-component 12d (inclination information of the surface 12f of the sub-component 12d that faces the substrate surface) from this height information.

[0064] In this way, by determining the height information of the surface 12f of the sub-component 12d facing the substrate 12a at multiple locations, the inclination information of this surface 12f can be calculated, and the mounting state of the sub-component 12d on the component 12b mounted on the object under inspection 12 can be determined in more detail.

[0065] (Variation of the height information calculation process) In the above explanation, as shown in Figure 6, we described the case of calculating the height information of the surface 12f of the component 12b attached to the substrate 12a of the object under inspection 12, specifically the surface 12f of the component 12b facing the substrate 12a (the height information of the surface 12f of the sub-component 12d attached to component 12b). However, using a similar method, as shown in Figure 10, it is also possible to calculate the height information of the surface of component 12b opposite to the substrate 12a (the height information of the surface 12f' of the sub-component 12d' attached to the surface of component 12b opposite to the substrate inspection surface 12e, which is the reference surface). In this case, the height information calculation unit 50 of the control unit 10, in steps S304 and S308 of the height information calculation process shown in Figure 5, selects the cross-sectional image data extracted as pseudo-cross-sectional image data from the side furthest from the reference plane (reference image data), and executes the judgment process described above. When the judgment conditions are met (when the amount of blur of the currently selected cross-sectional image data (the amount of blur calculated in step S310) is compared with the amount of blur of the cross-sectional image data adjacent to the substrate inspection surface 12e of this cross-sectional image data (the amount of blur calculated in step S306), and the amount of blur changes from a value greater than a predetermined threshold to a value less than or equal to a predetermined threshold), the unit can determine the position of the upper surface 12f' of the sub-component 12d' from the position in the Z-axis direction of the cross-sectional image data and calculate its height information H'. Furthermore, when calculating the height information of the side of component 12b opposite to the substrate 12a (the height information of the side 12f' opposite to the substrate inspection surface 12e of the sub-component 12d' attached to the side of component 12b opposite to the substrate 12a), the pseudo-cross-sectional image data needs to consist of cross-sectional image data covering a wider range than when calculating the height information of the side of component 12b on the substrate 12a side. In addition, the inclination information of the side of component 12b opposite to the substrate 12a (the side 12f' opposite to the substrate 12a of the sub-component 12d' attached to the side of component 12b opposite to the substrate 12a) can also be calculated using the height information of multiple locations calculated using the method described above. [Explanation of symbols]

[0066] 1. Inspection device 10 Control Unit 12. Subject under inspection 12a substrate 12b Part 12c solder ball 12d Sub-parts 12e Substrate surface (substrate inspection surface, reference surface) 12f The designated surface of the component (the surface facing the substrate surface of the sub-component) 22. Radiation generator (radiation source) 24 Board holding part (holding part) 26 Detectors

Claims

1. The radiation source and, A holding part that holds the object to be inspected, to which the part to be measured is attached, A detector that detects radiation from the source that has passed through the object to be inspected and acquires transmitted image data of the object to be inspected, It has a control unit and The control unit, A first step of generating three-dimensional image data composed of cross-sectional image data of the object to be inspected from the aforementioned transparent image data, A second step involves extracting a predetermined number of cross-sectional image data from a predetermined reference plane in the direction in which the component is positioned, A third step of identifying the position of the part in the extracted cross-sectional image data, A fourth step involves, in the extracted cross-sectional image data, calculating the amount of blurring of the outline of the part's image in the selected cross-sectional image data based on the position of the part identified in the third step, identifying cross-sectional image data in which a predetermined surface of the part has been captured based on the amount of blurring, and determining the position of the identified cross-sectional image data as the position of the predetermined surface of the part. A fifth step is performed to calculate height information from the reference surface to the predetermined surface based on the position of the reference surface and the position of the predetermined surface determined in the fourth step. In the fourth step described above, Step 4-1 involves sequentially selecting cross-sectional image data one by one from the cross-sectional image data extracted in the second step, in the direction in which the part is arranged, Step 4-2 involves calculating the amount of blurring of the outer shape of the image of the part in the cross-sectional image data selected in step 4-1, based on the position of the part identified in step 3 above, Step 4-3 involves determining whether the amount of blur in the previously selected cross-sectional image data is greater than a predetermined threshold, and whether the amount of blur in the currently selected cross-sectional image data has changed to a value less than or equal to the predetermined threshold. If it is determined that there has been no change, the process returns to step 4-1, the next cross-sectional image data is selected, and the subsequent processing is repeated. When it is determined in step 4-3 that the value of the blur amount has changed, step 4-4 is performed, which involves identifying the currently selected cross-sectional image data as cross-sectional image data in which a predetermined surface of the part has been captured, and determining the position of the identified cross-sectional image data as the position of the predetermined surface of the part. Inspection device.

2. In the fourth step, the control unit, The amount of blur is calculated by determining the distance between pixels within a predetermined range on a line that intersects a part of the outline, from a pixel with a threshold set as the lower limit to a pixel with a threshold set as the upper limit. The inspection apparatus according to claim 1.

3. In the fourth step, the control unit, The amount of blur is calculated by determining the distance from the minimum pixel to the maximum pixel among the pixels in a predetermined range on a line that intersects a part of the outline. The inspection apparatus according to claim 1.

4. In the third step, the control unit, In the second step, the average value of the pixels at the same position is calculated for each pixel of the cross-sectional image data extracted, and the position of the part is determined based on the average value of each pixel. The inspection apparatus according to any one of claims 1 to 3.

5. In the fourth step, the control unit, In the second step, the cross-sectional image data extracted is selected one by one from the reference plane side, and based on the position of the part determined in the third step, the amount of blurring of the outline of the image of the part in the selected cross-sectional image data is calculated, and the position of the cross-sectional image data when the amount of blurring changes from a value greater than a predetermined threshold to a value less than or equal to a predetermined threshold is determined as the position of a predetermined face of the part. The inspection apparatus according to any one of claims 1 to 3.

6. In the fourth step, the control unit, In the second step, the cross-sectional image data extracted is selected one by one from the side furthest from the reference plane, and based on the position of the part determined in the third step, the amount of blurring of the outline of the part's image in the selected cross-sectional image data is calculated, and the position of the cross-sectional image data when the amount of blurring changes from a value greater than a predetermined threshold to a value less than or equal to a predetermined threshold is determined as the position of a predetermined face of the part. The inspection apparatus according to any one of claims 1 to 3.

7. The control unit, In the fourth step, the amount of blur is calculated at two or more locations on the outer shape of the part, and based on the amount of blur at each location, cross-sectional image data in which a predetermined surface of the part is captured at each location is identified, and the position of the identified cross-sectional image data is determined to be the position of the predetermined surface of the part at each location. In the fifth step, based on the position of the reference plane and the position of the predetermined plane at each of the two or more locations determined in the fourth step, height information is calculated from the reference plane to the predetermined plane at each location, and further, based on the height information of the two or more locations, inclination information of the predetermined plane is calculated. The inspection apparatus according to any one of claims 1 to 3.

Images