Substrate inspection apparatus and substrate inspection method

Abstract

To provide a substrate inspection device capable of inspecting a plurality of parts of a substrate.SOLUTION: A substrate holder on which the substrate is placed; a first inspection section; a second inspection section; a third inspection section; a conveyance device which conveys the substrate holder between the first inspection section, the second inspection section, and the third inspection section in a state in which the substrate is placed on the substrate holder; and an image processing device, wherein the first inspection section includes a first light source which irradiates a first surface of the substrate with light and a first image pickup device which picks up an image of the first surface of the substrate, and, the second inspection part includes a second light source including a lower light source that irradiates a second surface located opposite to the first surface of the substrate with light, and a second imaging device that images the first surface of the substrate, the third inspection part includes a third light source that irradiates an end portion of the substrate with light, and a third imaging device that images the end portion of the substrate, and the image processing device processes images obtained by the first imaging device, the second imaging device, and the third imaging device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a substrate inspection device and a substrate inspection method. [Background technology]

[0002] Various substrates are used in the manufacture of semiconductor devices, etc. Substrates are required to have a smooth, even surface in order to be applicable to various applications such as semiconductor devices. For this reason, various studies have been conducted on substrate inspection devices and methods that can detect unevenness on the substrate surface.

[0003] For example, Patent Document 1 discloses a substrate inspection device that includes a light irradiation unit that irradiates light onto the inspected surface of the substrate, an imaging unit that acquires an image of the light irradiation unit reflected on the inspected surface, a moving unit that moves the image of the light irradiation unit reflected on the inspected surface by controlling the position of the substrate or the light irradiation unit, and an inspection unit that inspects the inspected surface by detecting an image formed when light irradiated from the light irradiation unit is scattered by a defective portion of the inspected surface and that is formed outside the contour line of the image of the light irradiation unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-020824 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inspection device described in Patent Document 1 has the problem that although it can inspect the front surface of the substrate, it cannot inspect the back surface of the substrate unless the substrate is turned over after the inspection of the front surface is completed. Also, there are cases where inspection of the edge surface of the substrate is also required.

[0006] That is, there has been a demand for a substrate inspection device that can inspect multiple locations on a substrate.

[0007] In view of the problems inherent in the above-described conventional techniques, an object of one aspect of the present invention is to provide a substrate inspection device capable of inspecting a plurality of locations on a substrate. [Means for solving the problem]

[0008] In order to solve the above problem, according to one aspect of the present invention, a substrate holder for placing a substrate; A first inspection department; A second inspection department; The third inspection department; a transport device that transports the substrate holder between the first inspection unit, the second inspection unit, and the third inspection unit while the substrate is placed on the substrate holder; an image processing device, the first inspection unit includes a first light source that irradiates light onto a first surface of the substrate, and a first imaging device that captures an image of the first surface of the substrate; the second inspection unit includes a second light source including a lower light source that irradiates light onto a second surface of the substrate that is located opposite to the first surface, and a second imaging device that images the first surface of the substrate; the third inspection unit includes a third light source that irradiates light onto the edge of the board, and a third imaging device that captures an image of the edge of the board; The image processing device provides a substrate inspection device that processes images obtained by the first imaging device, the second imaging device, and the third imaging device. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a substrate inspection device capable of inspecting a plurality of locations on a substrate. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a substrate inspection device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a top view of a substrate holder according to an embodiment of the present invention. [Figure 3A] FIG. 3A is a cross-sectional view taken along line AA′ in FIG. 2 showing an example of the configuration. [Figure 3B] FIG. 3B is another example of the cross section taken along the line AA′ in FIG. [Figure 4] FIG. 4 is an explanatory diagram of the imaging area. [Figure 5] FIG. 5 is an explanatory diagram of the transmission area. [Figure 6] FIG. 6 is an image of the substrate surface illustrating the detection state of a poling failure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention.

[0012] In the following explanation, the names of components and processes may be written with 1st, 2nd, 3rd, etc. added to them, such as the first inspection department, second inspection department, and third inspection department, or the first inspection process, second inspection process, and third inspection process. These 1st, 2nd, 3rd, etc. are written merely to distinguish between components and to prevent confusion during explanation, and do not represent placement, priority, etc. Therefore, when there is no particular risk of confusion or when referring to them collectively, they can be written simply as inspection department and inspection process. [Circuit board inspection equipment] For example, as shown in Figure 1, the substrate inspection apparatus 20 of this embodiment may have a substrate holder 10 for placing a substrate 100, a first inspection unit 21, a second inspection unit 22, a third inspection unit 23, and a conveying device 24.

[0013] 1 is a side view of the substrate inspection apparatus 20 of this embodiment, but is a schematic view for explaining the configuration of the substrate inspection apparatus 20 of this embodiment and does not accurately depict the size, scale, arrangement, etc. Also, for convenience of explanation, the substrate holder 10 is shown with substrates 100 placed in all inspection units, but since the substrate holder 10 is transported to each inspection unit by the transport device 24 and inspected, there may be only one substrate holder 10 for the entire substrate inspection apparatus 20. Also, the substrate inspection apparatus 20 may have two or more substrate holders 10 so that they do not interfere with each other on the transport path of the transport device 24.

[0014] 1 is an apparatus that can successively inspect the first surface 100A, second surface 100B, and side surface 100C of the substrate 100, and shows an example having a first inspection unit 21, a second inspection unit 22, and a third inspection unit 23, which will be described later. However, the substrate inspection apparatus of this embodiment is not limited to this form, and may further have a fourth inspection unit, etc.

[0015] The substrate holder, inspection unit, and transport device of the substrate inspection apparatus 20 of this embodiment will be described below. (1) Substrate holder The substrate holder 10 can accommodate a substrate, and with the substrate mounted, can be transported between inspection units by a transport device 24.

[0016] There is no particular limitation on the configuration of the substrate holder 10. The substrate holder 10 may be configured so that it can be transported by the transport device 24 with the substrate 100 placed thereon and can be inspected in each inspection section.

[0017] The substrate holder 10 can have, for example, a black base material and a substrate mounting portion.

[0018] An example of the configuration of each member of the substrate holder 10 will be described with reference to FIGS. 2, 3A, and 3B.

[0019] Fig. 2 is a top view of the substrate holder 10. Fig. 3A is one example of a cross-sectional view taken along line AA' in Fig. 2, and Fig. 3B is another example of a cross-sectional view taken along line AA' in Fig. 2. In Figs. 3A and 3B, the substrate 100 is also shown so that the relationship with the substrate 100 to be placed can be understood. (1-1) Black base material As shown in FIG. 2, the black substrate 12 of the substrate holder 10 can have an annular shape with a through-hole 11 in the center, or can have a plate-like shape as shown in FIGS. 3A and 3B.

[0020] The black substrate 12 is a substrate having at least the upper surface 12C (see FIGS. 3A and 3B) black, and in particular, the entire substrate including surfaces other than the upper surface 12C may be black.

[0021] By making the surface black, for example, when inspecting a substrate by irradiating it with light from a light source, the irradiated light is prevented from being reflected by the substrate holder and entering the imaging device, thereby reducing the impact on the image of the substrate.

[0022] The black substrate 12 can have an annular shape when viewed from above the substrate installation portion 13, but the outer shape does not need to be a perfect circle and may be an ellipse, etc. Furthermore, since the black substrate 12 has the cutout portion 14, it can have an annular shape with a portion broken off.

[0023] The black substrate 12 can have a plate-like shape, but since it has the substrate placement portion 13, it does not necessarily have to be plate-like in the strict sense. (Through hole) The black substrate 12 may have a through hole 11 in the center.

[0024] Since the substrate holder 10 has a through hole 11, when light is irradiated onto the second surface 100B, which is the back surface of the substrate 100 placed on the substrate holder 10, the unevenness of the second surface 100B of the substrate 100 can also be inspected using the light that passes through the substrate 100.

[0025] The diameter (inner diameter) of the through hole 11 can be smaller than the outer diameter of the substrate 100 to be placed on the substrate placement section 13. By making the diameter of the through hole 11 smaller than the outer diameter of the substrate 100 to be placed on the substrate placement section 13, the substrate 100 placed on the substrate placement section 13 can be supported by a convex portion 121 formed below the substrate placement section 13.

[0026] The width W121 of the convex portion 121 is not particularly limited, but as W121 increases, the area that can be evaluated by transmitted light becomes narrower. Therefore, the width W121 can be selected depending on the size of the inspection area required for the substrate 100, etc.

[0027] The width W121 of the convex portion 121 corresponds to the value obtained by subtracting the inner diameter of the through-hole 11 from the inner diameter D13 of the bottom surface of the substrate placement portion 13 and dividing the result by 2.

[0028] It is preferable that the through hole 11 is located in the center of the substrate holder 10, but since it is only provided to enable inspection using transmitted light as described above, it does not need to be located in a strictly central position. (Notched part) The black substrate 12 may have a cutout 14. The cutout 14 is provided so as to connect the through hole 11 and the outer surface 12A of the black substrate 12, i.e., so as to connect the inner peripheral surface 12B of the substrate holder 10 and the outer surface 12A. By providing the cutout 14, interference between the substrate holder 10 and a jig for holding the substrate 100, such as a robot arm or tweezers for suctioning a substrate, can be reduced when removing the substrate 100 from the substrate holder 10 or installing the substrate 100 in the substrate holder 10. This makes it easier to remove the substrate 100 from the substrate holder 10 or install the substrate 100 in the substrate holder 10. (1-2) Circuit board installation section The substrate mounting portion 13 can be provided on the upper surface 12C of the black substrate 12. The substrate mounting portion 13 is preferably a recessed portion that is arranged so that the substrate 100 covers the through-hole 11 when the substrate 100 is mounted on the substrate mounting portion 13.

[0029] For example, as shown in FIG. 2, the through-hole 11 and the substrate placement portion 13 may be arranged so as to form concentric circles when viewed from above the black substrate 12.

[0030] Furthermore, by making the substrate placement portion 13 a recess that is recessed from the upper surface 12C, the substrate 100 can be placed accurately in a predetermined location, and the substrate 100 can be prevented from moving within the substrate holder 10 during inspection, etc.

[0031] The inner diameter D13 of the recess of the substrate placement part 13 is preferably equal to or greater than the outer diameter of the substrate 100, as it is sufficient to insert the substrate 100 into the substrate placement part 13. It is more preferable to select the inner diameter D13 so that a gap of a predetermined size is formed between the substrate 100 and the substrate 100, so that the substrate 100 can be easily placed on and removed from the substrate placement part 13. However, it is also preferable to select the size of the gap so that movement of the substrate 100 during inspection can be restricted.

[0032] When the substrate mounting portion 13 is a recess, its depth is not particularly limited. For example, the depth may be selected so that the upper surface 12C of the black substrate 12 and the first surface 100A of the substrate 100 coincide with each other when the substrate 100 is mounted on the substrate mounting portion 13. Alternatively, the depth of the recess may be selected so that the upper surface 12C of the black substrate 12 and the first surface 100A of the substrate 100 do not coincide with each other when the substrate 100 is mounted on the substrate mounting portion 13. In other words, the depth of the recess may be deeper or shallower than the thickness of the substrate 100.

[0033] However, for example, as shown by the dotted line in Fig. 3A, when light source 31 is disposed diagonally above substrate 100 and light is irradiated near the edge of first surface 100A of substrate 100, if T13' corresponding to the depth of the recess is deeper than thickness T100 of substrate 100, as shown by the dotted line in Fig. 3A, there is a possibility that the light from light source 31 will be blocked. If the light from light source 31 is blocked, a shadow will be formed near the edge of substrate 100, which may make inspection impossible.

[0034] 3A, it is preferable that the depth T13 of the recess be equal to or less than the thickness T100 of the substrate 100 to be placed on the substrate placement section 13. By making the depth T13 of the recess equal to or less than the thickness T100 of the substrate 100, it is possible to prevent a shadow from being formed on the first surface 100A of the substrate 100 when light is irradiated onto the first surface 100A of the substrate 100, and to perform the inspection appropriately.

[0035] 3B, inner surface 13A of the recess that is substrate mounting portion 13 can be tapered so that the diameter increases from bottom surface 12D toward top surface 12C. By tapering the inner surface of the recess that is substrate mounting portion 13, even when depth T13 of the recess is approximately the same as thickness T100 of substrate 100, blocking of light and forming a shadow on first surface 100A of substrate 100 can be prevented, even when light is irradiated from diagonally above substrate 100. (1-1-3) Other materials The substrate holder 10 may also be provided with other optional members.

[0036] For example, the position of the substrate 100 placed on the substrate holder 10 can be changed by the irradiation area control device in order to change the position of the irradiation area on the substrate 100. In this case, the substrate inspection device 20 can also have a moving device that changes the position of the substrate holder 10 so that the substrate holder 10 can be moved in the horizontal direction. The transport device 24 can also serve as the moving device.

[0037] By providing the substrate inspection device 20 with a movement device, the position of the area on the substrate that is irradiated with light from the light source can be changed, and the entire surface of the substrate can be easily inspected, for example.

[0038] The substrate holder 10 may be provided with a means for correcting the tilt of the substrate 100 placed on the substrate holder 10 and making it horizontal, such as a tilt correction means to be described later.

[0039] The shape of the substrate 100 is not particularly limited, but for example, a disk-shaped substrate can be used. Furthermore, the substrate 100 may be provided with an orientation flat, a notch, or the like to indicate the crystal orientation of the substrate 100, as necessary. (2) First Inspection Department The first inspection unit 21 can have a first light source 211 that irradiates light onto the first surface 100A of the substrate 100, and a first imaging device 212 that images the first surface 100A of the substrate 100. Therefore, the first inspection unit 21 can irradiate light from the first light source 211 onto the first surface 100A of the substrate 100 placed on the substrate holder 10, for example, and inspect the first surface 100A of the substrate 100 for defects.

[0040] Each member of the first inspection unit 21 will be described below. (2-1) 1st light source In the first inspection unit 21, the first light source 211 is a member that irradiates light onto the first surface 100A, which is the surface of the substrate 100 placed on the substrate holder 10. The first light source 211 is only required to be configured to be able to irradiate light onto the first surface 100A of the substrate 100, and the specific configuration, such as the type of light source, is not particularly limited.

[0041] The first light source 211 can be disposed above the first surface 100A of the substrate 100 placed on the substrate holder 10 so that it can irradiate the first surface 100A of the substrate 100 with linear light, for example.

[0042] The linear light may have a linear shape on the first surface 100A of the irradiated substrate 100. The specific shape is not particularly limited, and may be any light selected from, for example, straight light, linear light including a bent portion, and wavy light. The shape of the bent portion of the linear light including a bent portion is not particularly limited, and may be, for example, an arc shape or an L-shape (L-shape) bent at a predetermined angle. The number of bent portions in the linear light including a bent portion is not particularly limited, and the linear light may have one or more bent portions. When the linear light including a bent portion has multiple bent portions, the shapes of the bent portions may be the same or may be different shapes. Furthermore, the wavy light is linear light in which bent portions are arranged while alternating in direction at predetermined intervals to form a wavy line. Linear light is particularly preferred as the linear light.

[0043] Linear light has a certain thickness, so it can also be called band-like light. For example, linear light is light with a substantially rectangular shape.

[0044] The longitudinal length of the linear light is not particularly limited, but from the viewpoint of efficient inspection, the length can be selected, for example, so that the light can be irradiated across the entire width of the substrate 100 to be inspected, forming a bright area.

[0045] The light emitting means of the first light source 211 is not particularly limited as long as it can produce linear light, but may be one or more types selected from, for example, a fluorescent lamp, an organic or inorganic electroluminescence (EL), a light emitting diode, a display, etc.

[0046] Furthermore, the wavelength of the light is not particularly limited, and may be any wavelength that allows at least a portion of the light to be reflected by the first surface 100A of the substrate 100 to be evaluated and allows a reflected image to be captured by the first imaging device 212. For this reason, the light emitted by the first light source 211 may be, for example, any of infrared light, visible light, and ultraviolet light, but since the first imaging device may become expensive or large in size depending on the wavelength of the light, it is preferable that the light emitted by the first light source 211 includes visible light.

[0047] In the substrate inspection device 20, when inspecting the unevenness of the first surface 100A of the substrate 100, the first inspection unit 21 can capture an image of a first imaging area on the first surface 100A of the substrate 100, which is along the longitudinal direction of the bright area and includes both the bright area and a dark area adjacent to the bright area. The bright area is an area that reflects linear light irradiated from the first light source 211 onto the first surface 100A of the substrate 100.

[0048] Then, photographing the first imaging area while changing the position of the bright area may be repeated until an image of the part to be inspected, for example an image of the entire first surface 100A of the substrate 100, is obtained when the images of the first imaging area obtained are stitched together.

[0049] For this reason, from the viewpoint of increasing the number of imaging areas that can be imaged simultaneously and reducing the number of imaging operations to improve inspection efficiency, it is preferable that the first light source 211 be capable of simultaneously irradiating multiple linear light beams that are parallel to each other. Therefore, it is preferable that the first light source 211 be configured to be able to irradiate the first surface 100A of the substrate 100 with multiple linear light beams that are parallel to each other. In this case, it is preferable to adjust the spacing between the multiple linear light beams so that dark areas are formed between multiple bright areas that reflect the multiple linear light beams irradiated onto the first surface 100A of the substrate 100. Note that when multiple linear light beams are irradiated onto the first surface 100A of the substrate 100, the linear light beams may have the same shape or different shapes. However, it is preferable that the multiple linear light beams have the same shape in order to facilitate inspection.

[0050] The first light source 211 may be fixed to, for example, a housing (not shown) installed in the substrate inspection device 20. However, the present invention is not limited to such a configuration, and the first light source 211 may also be fixed using a tripod or the like separately from other members. (2-2) First imaging device The first imaging device 212 can capture an image of the first surface 100A of the substrate 100 placed on the substrate holder 10.

[0051] According to studies by the inventors of the present invention, when linear light is irradiated onto first surface 100A of substrate 100, the contrast of the unevenness of first surface 100A of substrate 100 increases near the boundary between a bright region that reflects the linear light on first surface 100A of substrate 100 and a dark region adjacent to the bright region. Therefore, when inspecting the unevenness of first surface 100A of substrate 100, linear light is scanned over first surface 100A of substrate 100 to displace the position of the bright region that is formed, and first image capture device 212 can capture an image of the vicinity of the boundary between the bright region and the dark region adjacent to the bright region.

[0052] Specifically, the first imaging device 212 can image a first imaging area on the first surface 100A of the substrate 100, which is along the longitudinal direction of a bright area that reflects linear light and includes the bright area and a dark area adjacent to the bright area.

[0053] Here, the first imaging region imaged by the first imaging device 212 will be described with reference to FIG.

[0054] FIG. 4 shows first surface 100A of substrate 100, in which a single linear light beam is irradiated and a bright area 41A that reflects the linear light beam is formed.

[0055] In this way, linear light is irradiated from first light source 211 onto first surface 100A of substrate 100, and thereby bright region 41A that reflects the linear light is formed on first surface 100A of substrate 100. Bright region 41A is a linear (band-shaped) region that corresponds to the linear light from first light source 211.

[0056] The areas other than the bright area 41A reflect light from the first light source 211 to a low degree or do not reflect light at all, and therefore become dark areas 41B that are darker than the bright area 41A.

[0057] In this case, the first imaging device 212 can capture one or more areas selected from the first imaging areas 42A, 42B surrounded by dotted lines, including the bright area 41A and the dark area 41B adjacent to the bright area 41A, at least along the longitudinal direction of the bright area 41A, i.e., along the X-axis direction in the figure. In this case, it is sufficient to capture an image of at least the area including the first imaging area, and the periphery of the first imaging area may also be captured. When the periphery of the first imaging area is also captured, the first image processing device can cut out an image of the target imaging area from the captured image.

[0058] The arrangement of the bright and dark regions included in the first imaging region 42A, which is the region above the bright region 41A, is reversed from that of the first imaging region 42B, which is below the bright region 41A. Therefore, when the images of the first imaging region 42A are stitched together, the black and white (light and dark) of the resulting image is reversed from that when the images of the first imaging region 42B are stitched together. Therefore, it is possible to select the first imaging region to be imaged according to the image to be obtained.

[0059] The ratio of the area of ​​the bright region to the area of ​​the dark region included in each first imaging region is not particularly limited, and can be selected according to the type of substrate, etc., so that the contrast of the unevenness of the substrate surface is high when the images of the first imaging regions are stitched together by the image processing means. For example, the position of the first imaging region can be set so that the area of ​​the included bright region and the area of ​​the included dark region are equal.

[0060] When the captured images are collected three-dimensionally and handled as image volume data, the first imaging device may capture an image of the entire surface of the substrate including the first imaging region.

[0061] The first imaging device 212 is not particularly limited in configuration as long as it can capture an image of the first imaging region. A camera module equipped with various imaging elements can be used as the first imaging device 212. As the imaging element, for example, one or more types selected from semiconductor imaging elements such as a CMOS (complementary metal oxide semiconductor) sensor or a CCD (charge coupled device) sensor, a phototube, an imaging tube, etc. can be used.

[0062] The image captured by the first imaging device 212 may be a moving image or a still image. In the case of a moving image, for example, the first image processing device can extract and stitch together multiple still images of the imaging area at any timing from the captured images.

[0063] Furthermore, depending on the shape of the bright area, etc., the first imaging device 212 can be, for example, a line scan camera, as long as it is a device that can capture an image of a linear (strip) imaging area. A line scan camera is a camera module in which imaging elements are arranged in a straight line and can capture an image of a linear (strip) imaging area.

[0064] The first imaging device 212 can be fixed, for example, to a housing (not shown) of the board inspection device 20. However, the present invention is not limited to such a configuration, and the first imaging device 212 can also be fixed using a tripod or the like separately from other members. (2-3) First image processing device, first output device The first image processing device 213 , which is the image processing device 203 , can process the image captured by the first imaging device 212 .

[0065] The first image processing device 213 is an ASIC (application specific integrated circuit) or the like, and is responsible for processing the image captured by the first imaging device 212.

[0066] In the first image processing device 213, an image of the entire substrate surface can be formed by cutting out, for example, rectangular images corresponding to the first imaging region described above from the image captured by the first imaging device 212 according to the object of inspection, arranging them along the movement direction of the bright region, and stitching them together. At this time, image processing such as correcting the contrast in the image and binarization processing can also be performed as necessary.

[0067] When a moving image is captured by the first imaging device 212, the first image processing device 213 can also extract a plurality of still images of the imaging area at a predetermined timing.

[0068] The image created by the first image processing device 213 can also be output to the first output device 214, which is the output device 204, and unevenness and color irregularities on the surface of the substrate can be detected visually from the obtained image due to differences in contrast in the obtained image. Note that unevenness on the surface of the substrate can be detected from the image created by joining together the above-mentioned first imaging areas.

[0069] The configuration of the first output device 214 is not particularly limited, and can be, for example, a display unit such as a display of any kind, or a printing unit such as a printer.

[0070] The first image processing device 213 may be equipped with, for example, AI (artificial intelligence), and may be configured to detect and notify unevenness on the first surface 100A of the substrate 100 from the image of the substrate surface obtained as described above. Also, the image processing device or the like may be configured to detect and notify locations where unevenness or color unevenness occurs in the formed image using, for example, preset thresholds for chromaticity, brightness, etc.

[0071] The first image processing device 213 can be realized as software within one ASIC, but may also be realized in part or entirely as hardware by providing a plurality of ASICs, for example.

[0072] The first image processing device 213 can also three-dimensionally collect images captured by the first imaging device 212 and handle them as image volume data. The first image processing device 213 can then perform volume rendering processing on the image volume data of the first surface 100A of the substrate 100 obtained by the first imaging device 212. Specifically, the first image processing device 213 can extract an image of the first imaging region across the entire substrate surface by, for example, creating (rendering) an isosurface image of the image volume data at the luminance values ​​of the first imaging region. In this case, even if the light source, such as a fluorescent lamp, is tilted during imaging or the position of the light source is shifted from one photograph to another, the region with a predetermined luminance value will be common. Therefore, by dividing the image by the predetermined luminance value, the desired first imaging region can be extracted regardless of the number of photographs, making it easier to detect irregularities and color unevenness.

[0073] In the first image processing device 213, by treating the obtained image of the substrate surface as image volume data, brightness etc. can be set according to the size of the irregularities to be detected, the image volume data of the substrate surface can be divided, and an isosurface can be extracted.

[0074] The first inspection section 21 of the substrate inspection device 20 of this embodiment may further include any other members in addition to the above-mentioned members. (2-4) Other The first inspection unit 21 of the substrate inspection device 20 may further include, for example, a tilt correction means for making the substrate horizontal. The tilt correction means may be provided, for example, in the substrate holder described above or in the body of the substrate inspection device of this embodiment, and may be configured to correct the tilt so that the surface of the substrate to be inspected is horizontal with respect to the light source. (3) Second Inspection Department The second inspection unit 22 can include a second light source 221 including a lower light source 2211 that irradiates light onto the second surface 100B, which is the back surface of the substrate 100 opposite the first surface 100A, and a second imaging device 222 that images the first surface 100A of the substrate 100. Therefore, the second inspection unit 22 can irradiate light from the second light source 221 onto the second surface 100B, which is the back surface of the substrate 100 placed on the substrate holder 10, and inspect the second surface 100B of the substrate 100 for defects using the transmitted light that passes through the substrate 100. The second inspection unit 22 can also inspect the first surface 100A of the substrate 100 for color unevenness, etc. Furthermore, if the substrate 100 is a single crystal substrate made of a ferroelectric material, the second inspection unit 22 can also inspect for poling defects.

[0075] Each member of the second inspection section 22 will be described below. (3-1)Second light source In the second inspection unit 22, the second light source 221 can include a bottom light source 2211 that irradiates light onto the second surface 100B, which is the back surface of the substrate 100 placed on the substrate holder 10. The second light source 221 can be configured only with the bottom light source 2211, or the second light source 221 can further include an top light source 2212 that irradiates light onto the first surface 100A of the substrate 100 placed on the substrate holder 10. Therefore, the second light source 221 can be configured only with the bottom light source 2211, or can include the bottom light source 2211 and the top light source 2212. (bottom light source) The lower light source 2211 of the second light source 221 is not particularly limited in its specific configuration, such as the type of light source, as long as it is configured to be able to irradiate light onto the second surface 100B of the substrate 100. The second light source 221 can be arranged on the second surface 100B side of the substrate 100 placed on the substrate holder 10, i.e., on the lower side, so that it can irradiate light onto the second surface 100B of the substrate 100.

[0076] The shape of the light that the bottom light source 2211 irradiates onto the substrate 100 is not particularly limited and can be selected depending on the content of the inspection, etc. The bottom light source 2211 can also irradiate, for example, linear light onto the second surface 100B of the substrate 100. Furthermore, when inspecting for poling defects, for example, the bottom light source 2211 can also irradiate light of any shape onto the second surface 100B of the substrate 100.

[0077] The shape of the linear light and the like can be configured in the same way as in the case of the first light source 211 described in the first inspection unit 21, so a duplicated description will be omitted.

[0078] In the second inspection section 22, the second imaging device 222 can capture an image of a transmission region, which is a region of the first surface 100A of the substrate 100 through which light irradiated from the lower light source 2211 of the second light source 221 to the second surface 100B has passed. It is preferable to repeatedly capture images of the transmission region while changing the position of the transmission region until an image of the portion to be inspected, for example, an image of the entire first surface 100A of the substrate 100, is obtained when the obtained images of the transmission region are stitched together.

[0079] Therefore, from the viewpoint of increasing the number of transmission regions that can be imaged simultaneously and reducing the number of times that images are taken to make the inspection more efficient, it is preferable that the lower light source 2211 of the second light source 221 can simultaneously irradiate a plurality of linear light beams that are parallel to each other. Therefore, it is preferable that the lower light source 2211 is configured to be able to irradiate a plurality of linear light beams that are parallel to each other onto the second surface 100B of the substrate 100.

[0080] When the lower light source 2211 irradiates the second surface 100B of the substrate 100 with a plurality of linear lights, it is preferable to adjust the spacing between the linear lights so that dark regions are formed between a plurality of transmission regions that have transmitted the linear lights irradiated onto the substrate. When a plurality of linear lights are irradiated onto the second surface 100B of the substrate 100, the linear lights may have the same shape or different shapes. However, it is preferable that the linear lights have the same shape in order to facilitate inspection.

[0081] The lower light source 2211 can be fixed to, for example, a housing (not shown) installed in the substrate inspection device 20. However, the present invention is not limited to such a configuration, and the second light source 221 can also be fixed using a tripod or the like separately from other members. (Top light source) The second light source 221 may also include an upper light source 2212 .

[0082] The upper light source 2212 is not particularly limited in its specific configuration, such as the type of light source, as long as it is configured to be able to irradiate light onto the first surface 100A of the substrate 100. The upper light source 2212 can be disposed above the first surface 100A of the substrate 100 placed on the substrate holder 10 so as to be able to irradiate light onto the first surface 100A of the substrate 100.

[0083] The shape of the light that the upper light source 2212 irradiates onto the substrate 100 is not particularly limited and can be selected depending on the content of the inspection, etc. The upper light source 2212 can also irradiate, for example, linear light onto the first surface 100A of the substrate 100. Furthermore, when inspecting for poling defects, for example, the upper light source 2212 can also irradiate light of any shape onto the first surface 100A of the substrate 100.

[0084] The upper light source 2212 can be configured in the same manner as the first light source 211 of the first inspection unit 21, for example, and therefore a description thereof will be omitted here. (3-2) Second imaging device The second imaging device 222 can be an imaging device similar to the first imaging device 212 described in the first inspection section 21.

[0085] The second inspection unit 22 can inspect the substrate surface for color unevenness, defects, etc. Furthermore, if the substrate 100 is a single crystal substrate made of a ferroelectric material, the second inspection unit 22 can also inspect for the presence or absence of poling defects.

[0086] When inspecting color unevenness on the first surface 100A of the substrate 100, an upper light source 2212 is used to irradiate light onto the first surface 100A of the substrate while capturing an image of a predetermined position on the first surface 100A of the substrate 100, and inspection can be performed from the obtained image.

[0087] When inspecting defects on the second surface 100B of the substrate 100, a predetermined position on the first surface 100A of the substrate 100 is imaged while irradiating light onto the second surface 100B of the substrate 100 using the lower light source 2211, and inspection can be performed from the obtained image.

[0088] The imaging areas when inspecting the first surface 100A of the substrate 100 for color unevenness and when inspecting the second surface 100B of the substrate 100 for defects will be described below. (When inspecting color unevenness on the surface of a board) 4 shows the first surface 100A of the substrate 100, and illustrates a state in which linear light is irradiated from the upper light source 2212 of the second light source 221. By irradiating the first surface 100A of the substrate 100 with linear light from the upper light source 2212 in this manner, a bright region 41A that reflects the light from the upper light source 2212 is formed on the first surface 100A of the substrate 100.

[0089] The area of ​​the first surface 100A of the substrate 100 other than the bright area 41A is not directly irradiated with light from the upper light source 2212, and therefore forms a dark area 41B that is darker than the bright area 41A. The second imaging device 222 can image the second imaging area 43 outside the bright area 41A, i.e., the area surrounded by the dotted line in the dark area 41B, for example, at least along the longitudinal direction of the bright area 41A, i.e., along the X-axis direction in the figure. In this case, it is sufficient to image at least the area including the second imaging area 43, and the periphery of the second imaging area 43 may also be imaged. When the area surrounding the second imaging area 43 is also imaged, the second image processing device can extract an image of the desired second imaging area from the captured image.

[0090] Here, the case where light from upper light source 2212 is directly irradiated onto first surface 100A of substrate 100 has been described as an example, but when inspecting color unevenness, light from upper light source 2212 does not need to be directly irradiated onto first surface 100A of substrate 100. For example, light irradiated from upper light source 2212 may be irradiated onto a location other than first surface 100A of substrate 100, and the location may be illuminated by the indirect light that is reflected.

[0091] However, in order to detect color unevenness, it is preferable that the degree of brightness within second imaging region 43 due to light from upper light source 2212 is uniform. Therefore, it is preferable to irradiate first surface 100A of substrate 100 or its vicinity with light from upper light source 2212, set a second imaging region along the longitudinal direction of the bright region, and capture an image. Furthermore, it is preferable to set the region so that the length perpendicular to the longitudinal direction of second imaging region 43 is not excessively long, so that the degree of brightness within second imaging region 43 due to light from upper light source 2212 is uniform. Here, the length perpendicular to the longitudinal direction of second imaging region refers to the length in the Y-axis direction in FIG. 4.

[0092] The second image processing device can also stitch together the images of the second imaging regions 43 captured to form an image of the entire substrate surface. From the viewpoint of detecting color unevenness more accurately from the formed image of the entire substrate surface, it is preferable that the brightness of the formed image of the entire substrate surface be uniform. That is, it is preferable that the brightness of the images of the multiple second imaging regions 43 constituting the image of the entire substrate surface be uniform. Therefore, when changing the position of the bright region 41A formed by irradiation with linear light from the upper light source 2212, it is preferable to maintain a constant distance between the bright region 41A and the second imaging region 43.

[0093] When the captured images are collected three-dimensionally and handled as image volume data, the second imaging device 222 may capture an image of the entire first surface 100A of the substrate 100 including the second imaging region. (When inspecting defects on the second surface, which is the back side of the board) The transmission area imaged by the second imaging device 222 will be described with reference to FIG.

[0094] 5 shows the first surface 100A of the substrate 100, and the second surface 100B, which is positioned opposite the first surface 100A of the substrate 100, is the surface onto which linear light is irradiated from the lower light source 2211. Fig. 5 also shows a state in which one linear light is irradiated onto the second surface 100B from the lower light source 2211, and a corresponding transmissive region 51A is formed on the first surface 100A.

[0095] When linear light is irradiated from first light source 211 onto second surface 100B of substrate 100, a transmission region 51A that transmits the light from the light source is formed on first surface 100A of substrate 100. Transmission region 51A is a linear (band-shaped) region that corresponds to the linear light from first light source 211.

[0096] The areas other than transmissive area 51A transmit little or no light from the light source, and therefore become dark areas that are darker than transmissive area 51A, forming dark areas 51B on substrate 100.

[0097] In this case, the second imaging device 222 can capture an image of the transparent region 51A. However, the second imaging device 222 only needs to capture an image of the region including the transparent region 51A, and can also capture an image of the surrounding area of ​​the transparent region 51A. For example, the third imaging region 52, which is surrounded by a dotted line and includes the transparent region 51A, can be captured along the longitudinal direction of the transparent region 51A, i.e., along the X-axis in the figure. When capturing an image of the transparent region 51A, if the surrounding area is also captured, the second image processing device can extract an image of the desired transparent region from the captured image.

[0098] The image captured by the second imaging device 222 may be a moving image or a still image. In the case of a moving image, for example, an image processing means can extract and use a plurality of still images of the transparent region at any timing from the captured images. (When checking for polling failures) When the substrate 100 is a single crystal substrate made of a ferroelectric material, the presence or absence of poling defects can also be inspected in the second inspection unit 22. When the substrate 100 is a single crystal substrate made of a ferroelectric material, the substrate 100 may be a single crystal substrate made of lithium tantalate or lithium niobate.

[0099] When inspecting for poling defects, second light source 221 may be a lower light source 2211 that irradiates light onto second surface 100B, or an upper light source 2212 that irradiates light onto first surface 100A.

[0100] The irradiation area is an area formed on the first surface 100A of the substrate 100 that reflects or transmits light with a predetermined level of brightness or more when light is irradiated onto the substrate 100 from the lower light source 2211 or the upper light source 2212. In this case, the size and shape of the irradiation area are not limited. The irradiation area has a shape such as a line or a strip, and may be formed on a part of the first surface 100A of the substrate 100, or may be formed on the entire first surface 100A of the substrate 100.

[0101] If the illumination area is formed on a portion of the first surface 100A of the substrate 100 rather than the entire surface, it is preferable to move the illumination area over the first surface 100A of the substrate 100 during inspection so that the illumination area passes over the entire first surface 100A of the substrate 100.

[0102] The brightness of the light in the irradiated area is not particularly limited, and can be determined, for example, according to the material of the substrate, by conducting a preliminary test or the like so that poling defects can be detected.

[0103] Furthermore, the wavelength of the light emitted from the second light source 221 is not particularly limited, as long as at least a portion of the light is reflected by or transmitted through the substrate 100 to be evaluated and the reflected or transmitted light can be imaged by the second imaging device 222. For this reason, the light emitted by the second light source 221 may be, for example, infrared light, visible light, or ultraviolet light, but since the imaging device may become expensive or large in size depending on the wavelength of the light, it is preferable that the light emitted by the light source includes visible light.

[0104] The second imaging device 222 can capture an image of the portion of the first surface 100A of the substrate 100 that is irradiated with light from the second light source 221.

[0105] When light is irradiated from the upper light source 2212 onto the first surface 100A of the substrate 100, the second imaging device 222 can irradiate the first surface 100A of the substrate 100 and capture an image of the reflected light.

[0106] When light is irradiated from the lower light source 2211 onto the second surface 100B of the substrate 100, the second imaging device 222 can irradiate the light onto the second surface 100B of the substrate 100 and capture an image of the light that is transmitted from the second surface 100B of the substrate 100 to the first surface 100A of the substrate 100.

[0107] More specifically, the second imaging device 222 can image an illuminated area formed on the first surface 100A of the substrate 100, which is an area that reflects or transmits light with a brightness equal to or greater than a predetermined amount. (3-3) Second image processing device The second image processing device 223, which is the image processing device 203, can process images captured by the second imaging device 222. The second image processing device 223 can be configured in the same way as the first image processing device 213 of the first inspection unit 21, except for using images captured by the second imaging device 222, and therefore a description thereof will be omitted.

[0108] The image created by the second image processing device 223 can also be output to the second output device 224, which is the output device 204, and the difference in contrast in the obtained image makes it possible to visually detect unevenness and color unevenness on the back surface of the substrate from the obtained image. The second output device 224 can also be configured in the same way as the first output device 214 of the first inspection unit 21, so a description thereof will be omitted.

[0109] The second image processing device 223 can also process the image captured by the second imaging device 222 so that areas with poor poling can be identified. Specifically, for example, the second image processing device 223 can adjust the contrast of the image obtained by the second imaging device 222 so that areas with poor poling can be identified.

[0110] A region with poor poling refers to a region where the poling process is insufficient and the polarization direction is not aligned, or a region that contains foreign matter or bubbles within the crystal. Poling is a process specific to ferroelectric material crystals, and is a process or treatment that aligns the electrical polarity generated by spontaneous polarization, which is a characteristic of ferroelectric crystals, in one direction.

[0111] In addition, areas with poling defects may be detected visually from the obtained image, or the second image processing device 223 may be configured to detect an area as having a poling defect if there is a difference in contrast with other areas by a certain amount or more. (3-4) Other The second inspection unit 22 of the substrate inspection apparatus 20 of this embodiment may further include, for example, a tilt correction means for making the substrate horizontal. The tilt correction means may be provided, for example, in the substrate holder 10 or the body of the substrate inspection apparatus 20, and may be configured to correct the tilt so that the surface of the substrate 100 to be inspected is horizontal with respect to the second light source 221. (4) Third Inspection Department The third inspection section 23 can include a third light source 231 that irradiates light onto the edge of the substrate 100, and a third imaging device 232 that captures an image of the edge of the substrate 100. Therefore, the third inspection section 23 can irradiate the edge including the side surface 100C of the substrate 100 with light from the third light source 231, and inspect the edge including the side surface 100C of the substrate 100 for defects.

[0112] Each member of the third inspection unit 23 will be described below. (4-1) Third light source The configuration of the third light source 231 is not particularly limited as long as it is configured to be able to irradiate light onto the edge portion including the side surface 100C of the substrate 100. For example, as shown in Fig. 3, the third light source 231 may have a lower light source 2311 arranged below the substrate 100 and an upper light source 2312 arranged above the substrate 100. However, without being limited to this form, the third light source 231 may be configured with only one of the lower light source 2311 and the upper light source 2312, or may be configured with one light source arranged to face the side surface 100C of the substrate 100.

[0113] The third light sources 231 such as the lower light source 2311 and the upper light source 2312 can have the same configuration, and therefore will be described together.

[0114] The third light source 231 is not particularly limited in its specific configuration, such as the type of light source, as long as it is configured to be able to irradiate light onto the side surface 100C of the substrate 100. The third light source 231 can be arranged so that it can uniformly irradiate light onto the side surface 100C of the substrate 100 while it is supported by the substrate rotation device 235. By irradiating light onto the side surface 100C of the substrate 100, chipped portions included in the edge of the substrate 100 can be easily identified.

[0115] The light emitting means of the third light source 231 is not particularly limited, but may be one or more selected from, for example, a fluorescent lamp, an organic or inorganic electroluminescence (EL), a light emitting diode, a display, and the like.

[0116] The wavelength of the light from the third light source 231 is not particularly limited, and may be, for example, any wavelength that can reflect at least a portion of the light at the end surface of the substrate 100 to be evaluated and capture a reflected image by the third imaging device 232. For this reason, the light emitted by the third light source 231 may be, for example, any of infrared light, visible light, and ultraviolet light, but the third imaging device may become expensive or large in size depending on the wavelength of the light, so it is preferable that the light emitted by the third light source 231 includes visible light. (4-2) Third imaging device The third imaging device 232 can capture an image of the edge of the substrate 100 including the side surface 100C.

[0117] The third imaging device 232 can be an imaging device similar to the first imaging device 212 described in the first inspection section 21, and therefore a description thereof will be omitted.

[0118] The image captured by the third imaging device 232 may be a moving image or a still image. In the case of a moving image, for example, the third image processing device 233 can extract and stitch together multiple still images of the imaging area at any timing from the captured images.

[0119] The third imaging device 232 may be a line scan camera, since it is sufficient for it to be a means capable of capturing an image of the area of ​​the substrate 100 that is irradiated with light from the third light source. (4-3) Third image processing device, third output device The third image processing device 233, which is the image processing device 203, processes the image captured by the third imaging device 232, and can make it possible to identify defects contained in the edge of the substrate 100.

[0120] In the third image processing device 233, an image of the end portion of the side surface 100C of the substrate 100, etc., can be cut out as necessary from the image captured by the third imaging device 232 and stitched together to form an image of the entire end portion of the side surface 100C of the substrate 100, etc.

[0121] The third image processing device 233, which is the image processing device 203, can be configured in the same way as the first inspection section 21, the first image processing device 213 of the second inspection section 22, and the second image processing device 223, except that it uses images captured by the third imaging device 232, so explanation will be omitted.

[0122] The image created by the third image processing device 233 can also be output to the third output device 234, which is the output device 204, and irregularities on the edge of the substrate can be visually detected from the obtained image due to differences in contrast in the obtained image. The third output device 234 can also be configured in the same way as the first output device 214 of the first inspection unit 21, so a description thereof will be omitted. (4-4) Substrate rotation device The substrate rotation device 235 can support and lift the second surface 100B of the substrate 100 that is placed on the substrate holder 10 and transported to the third inspection unit 23. This allows the substrate 100 to be removed from the substrate holder 10, and the edge of the substrate 100, including the side surface 100C, to be imaged by the third imaging device 232.

[0123] In the third inspection section 23, since the side surface 100C of the substrate 100 can be inspected, it is preferable that the substrate rotation device 235 is configured to be able to rotate the supported substrate 100. By rotating the substrate 100 about its central axis, the third imaging device 232 can capture an image of the entire end portion of the substrate 100, including the side surface 100C. (5) Conveying device 1, the substrate inspection apparatus 20 of this embodiment can have a transport device 24 that transports the substrate 100 between each inspection unit. The transport device 24 can transport the substrate holder 10 between the first inspection unit 21, the second inspection unit 22, and the third inspection unit 23, with the substrate 100 placed on the substrate holder 10. Therefore, the transport device 24 can transport the substrate 100 placed on and supported by the substrate holder 10.

[0124] The configuration of the conveying means 34 is not particularly limited, and a single-axis actuator or the like can be used. (6) Image processing device The image processing device 203 can process images obtained by the first imaging device 212, the second imaging device 222, and the third imaging device 232. As explained above, the image processing device 203 can be provided in each inspection unit. Also, the image processing device 203 can be integrated into some or all of the inspection units.

[0125] The image processing device has been explained for each inspection unit, so its explanation will be omitted. (7) Output device The output device 204 can output images created by the first image processing device 213, the second image processing device 223, and the third image processing device 233. As explained above, the output device 204 can be provided in each inspection unit. Also, the output device 204 can be integrated for some or all of the inspection units.

[0126] The output device has been explained for each inspection unit, so the explanation will be omitted.

[0127] According to the substrate inspection device of this embodiment described above, it has a first inspection unit 21, a second inspection unit 22, and a third inspection unit 23, and the substrate to be inspected can be transported between the inspection units using a transport device, making it possible to easily inspect multiple locations on the substrate. [Board inspection method] Next, a substrate inspection method according to the present embodiment will be described. Note that the substrate inspection method according to the present embodiment can be implemented using a substrate inspection device according to one aspect of the present disclosure. Therefore, some of the matters that have already been described will not be described again.

[0128] The substrate inspection method of this embodiment can have a first inspection step, a second inspection step, a third inspection step, and an image processing step.

[0129] Each step will be described below. (1) First inspection process The first inspection step can include a first light irradiation step and a first imaging step. (1-1) First light irradiation step In the first light irradiation step, the first surface 100A of the substrate 100 placed on the substrate holder 10 can be irradiated with light from the first light source 211. (1-2) First imaging step In the first imaging step, the first surface 100A of the substrate 100 can be imaged by the first imaging device 212.

[0130] The first light irradiation step and the first imaging step can be carried out consecutively.

[0131] In the first light irradiation step, light can be continuously irradiated onto the first surface 100A of the substrate 100 while changing the position on the first surface 100A of the substrate 100 where the light is irradiated. In the first light irradiation step, the position where the light is irradiated can be changed so that the area to be inspected, for example, the entire first surface 100A of the substrate 100, can be irradiated with light.

[0132] In the first imaging step, the area to be imaged is changed in accordance with the change in the position on the first surface 100A of the substrate 100 where light is irradiated in the first light irradiation step, and an image of the entire first surface 100A of the substrate 100 can be acquired, for example.

[0133] In the first inspection step, the first surface 100A of the substrate 100 can be inspected for defects using the light reflected from the first surface 100A of the substrate 100. (2) Second inspection process The second inspection step can include a second light irradiation step and a second imaging step. (2-1) Second light irradiation process In the second light irradiation step, the second surface 100B of the substrate 100 placed on the substrate holder 10, which is located opposite to the first surface 100A, can be irradiated with light from the second light source 221, specifically the lower light source 2211. (2-2) Second imaging step In the second imaging step, the first surface 100A of the substrate 100 can be imaged by the second imaging device 222.

[0134] The second light irradiation step and the second imaging step can be carried out consecutively.

[0135] In the second light irradiation step, light can be continuously irradiated onto the second surface 100B of the substrate 100 while changing the position on the second surface 100B of the substrate 100 where the light is irradiated. In the second light irradiation step, the position where the light is irradiated can be changed so that the region to be inspected, for example, the entire second surface 100B of the substrate 100, can be irradiated with light.

[0136] In the second imaging step, the area to be imaged is changed in accordance with the change in the position where light is irradiated on the second surface 100B of the substrate 100 in the second light irradiation step, and it is possible to obtain, for example, an image of the entire first surface 100A of the substrate 100. In the second imaging step, transmitted light that has passed through the substrate 100 is imaged.

[0137] When the second inspection section 22 has an upper light source 2212, the first surface 100A of the substrate 100 may be irradiated with light from the second light source 221, specifically the upper light source 2212, in the second light irradiation step.

[0138] While the upper light source 2212 is irradiating the first surface 100A of the substrate 100 with light, the lower light source 2211 stops irradiating the second surface 100B of the substrate 100 with light. Then, in the second imaging step, the first surface 100A of the substrate 100 can be imaged by the second imaging device 222. In the second imaging step, the portion of the first surface 100A of the substrate 100 corresponding to the region where the upper light source 2212 is irradiating the first surface 100A of the substrate 100 with light can be imaged.

[0139] Regarding the second light irradiation step, if it is necessary to distinguish between the step of irradiating light onto the second surface 100B of the substrate 100 and the step of irradiating light onto the first surface 100A of the substrate 100, the names may be different. For example, the second light irradiation step of irradiating light onto the second surface 100B of the substrate 100 may be called a second backside light irradiation step, and the second light irradiation step of irradiating light onto the first surface 100A of the substrate 100 may be called a second front side light irradiation step. Similarly, the names of the corresponding second imaging steps may be different so as to be distinguishable.

[0140] In the second inspection step, the first surface 100A and the second surface 100B of the substrate 100 can be inspected for defects using transmitted light that passes from the second surface 100B of the substrate 100 to the first surface 100A. (3) Third inspection process The third inspection step can include a third light irradiation step and a third imaging step. (3-1) Third light irradiation process In the third light irradiation step, the edge of the substrate 100 can be irradiated with light from the third light source 231. (3-2) Third imaging step In the third imaging step, the edge of the substrate 100 can be imaged by the third imaging device 232 .

[0141] The third light irradiation step and the third imaging step can be carried out consecutively.

[0142] In the third light irradiation process, for example, the substrate 100 is rotated by a substrate rotation device 235, and the position of the light irradiated from the third light source 231 on the end face including the side surface 100C of the substrate 100 is changed, thereby continuously irradiating the end of the substrate 100 with light.

[0143] In the third imaging step, the area to be imaged is changed in accordance with the change in the position on the edge of the substrate 100 where light is irradiated in the third light irradiation step, and an image of the entire edge of the substrate 100, for example, can be acquired.

[0144] In the third inspection step, the edge portion including the side surface 100C of the substrate 100 is irradiated with light from the third light source 231, and the edge portion including the side surface 100C of the substrate 100 can be inspected for defects. (4) Image processing process In the image processing step, the images obtained in the first, second, and third imaging steps can be processed to enable identification of defects on the substrate. The image processing in the image processing step can also be selected depending on the content of the inspection, and for example, the captured images can be stitched together or the contrast of the obtained images can be adjusted. Furthermore, if a video is captured in each imaging step, multiple still images can be extracted at a predetermined timing in the image processing step and stitched together as necessary.

[0145] Then, due to differences in contrast in the image obtained in the image processing step, defects and the like can be detected from the obtained image of the substrate 100. For this reason, it is preferable that the image processing step adjusts the contrast of the image obtained in the imaging step so that defects and the like can be identified.

[0146] Defects on the substrate may be detected visually from the obtained image, or may be detected as defects if there is a difference in contrast with other parts by a certain amount or more through an image processing process.

[0147] When the substrate 100 is a single crystal substrate made of a ferroelectric material, the substrate inspection method of this embodiment can also inspect for poling defects. When the substrate 100 is a single crystal substrate made of a ferroelectric material, the substrate 100 may be a single crystal substrate made of lithium tantalate or lithium niobate.

[0148] In this case, in the image processing step, the image obtained in the second imaging step can be processed so that areas of poling failure can be identified.

[0149] In the image processing step, an image of the entire surface of the substrate can be formed by cutting out, as necessary, a strip-shaped image corresponding to the irradiation area from the image captured in the second imaging step, arranging the images along the direction of movement of the irradiation area, and stitching them together.

[0150] When a moving image is captured in the second capturing step, a plurality of still images can be extracted at a predetermined timing in the image processing step, and can be joined together as necessary.

[0151] Then, due to differences in contrast in the image obtained in the image processing step, poling defects can be detected from the obtained image of the first surface 100A of the substrate 100. Specifically, areas with poling defects can be detected and identified as areas with higher contrast than other areas, such as the white part in area 60 in Figure 6.

[0152] Therefore, when inspecting for the presence or absence of poling defects, it is preferable that in the image processing step, the contrast of the image obtained in the second imaging step is adjusted so that areas with poling defects can be identified.

[0153] Furthermore, the image processing step may be configured to use, for example, AI (artificial intelligence) to detect and notify defects on the substrate from the image of the substrate surface obtained as described above.

[0154] The image processing step may be performed in each inspection step. Therefore, it may be performed in each inspection step as a first image processing step, a second image processing step, and a third image processing step. Furthermore, the image processing step may be performed after each inspection step is completed, or may be performed in parallel while each inspection step is being performed. (5) Other processes The substrate inspection method of this embodiment is not limited to the above steps and may further include any steps, such as a tilt correction step and a transport step. (Tilt correction process) For example, the method may further include a tilt correction step for leveling the substrate placed on the substrate holder.

[0155] The specific method for adjusting the substrate to be horizontal is not particularly limited, but for example, a tilt correction means for adjusting the horizontality can be provided on the substrate holder or the housing (body) of the substrate inspection device 20, and the horizontality can be adjusted automatically or manually.

[0156] The tilt correction process may be performed before each inspection process is started. (Transportation process) In the transfer step, the substrate holder 10 can be transferred with the substrate 100 placed on the substrate holder 10.

[0157] By transporting the substrate holder 10 in the transport step, the substrate can be easily transported to the inspection section for carrying out each inspection step.

[0158] The substrate inspection method of this embodiment may perform only a selected part of the first inspection step, the second inspection step, and the third inspection step, or may perform all of the steps.

[0159] The order in which the first inspection step, second inspection step, and third inspection step are performed is not particularly limited, and they can be performed at any timing and in any order.

[0160] The substrate inspection method of this embodiment may be implemented using a substrate inspection device according to one aspect of the present disclosure. For example, the first inspection step can be implemented in the first inspection unit, the second inspection step can be implemented in the second inspection unit, and the third inspection step can be implemented in the third inspection unit. Therefore, the matters that have already been explained will not be explained again.

[0161] According to the substrate inspection method of this embodiment described above, it has the first inspection step, the second inspection step, and the third inspection step, and can easily inspect multiple locations on the substrate to be inspected. [Explanation of symbols]

[0162] 10 Substrate holder 11 Through hole 12 Black base material 13 Circuit board installation section T13, T13´ Recess depth D13 Inner diameter 14 Notch 100 boards 100A First Surface 100B 2nd surface 100C side T100 board thickness 12A Outer surface 12B Inner surface 12C Top 12D bottom 121 Convex part W121 width 20 Circuit board inspection equipment 203 Image Processing Device 204 Output Device 21 First Inspection Department 211 1st light source 212 First imaging device 213 First image processing device 214 First Output Device 22 Second Inspection Department 221 Second light source 2211 Lower light source (second light source) 2212 Upper light source (second light source) 222 Second Imaging Device 223 Second Image Processing Device 224 Secondary Output Device 23 Third Inspection Department 231 Third light source 2311 Lower light source (3rd light source) 2312 Upper light source (third light source) 232 Third Imaging Device 233 Third Image Processing Device 234 Third Output Device 235 Substrate Rotation Device 31 Light source 41A Light area 41B Dark region 42A, 42B First imaging area 43 Second imaging area 51A Transmission area 51B Dark region 52 Third imaging area

Claims

1. a substrate holder for placing a substrate; A first inspection unit; A second inspection unit; A third inspection department; a transport device that transports the substrate holder between the first inspection unit, the second inspection unit, and the third inspection unit while the substrate is placed on the substrate holder; an image processing device, the first inspection unit includes a first light source that irradiates light onto a first surface of the substrate, and a first imaging device that images the first surface of the substrate; the second inspection unit includes a second light source including a lower light source that irradiates light onto a second surface of the substrate that is positioned opposite to the first surface, and a second imaging device that images the first surface of the substrate; the third inspection unit includes a third light source that irradiates light onto an edge of the board, and a third imaging device that captures an image of the edge of the board, The image processing device processes images obtained by the first imaging device, the second imaging device, and the third imaging device.

2. the substrate holder a plate-like black substrate having an annular shape with a through hole in the center; a substrate mounting portion provided on an upper surface of the black substrate, the diameter of the through hole is smaller than the outer diameter of the substrate to be placed on the substrate placement section, the substrate placement section is a recessed section that is arranged so that the substrate covers the through hole when the substrate is placed on the substrate placement section, The substrate inspection device according to claim 1 , wherein the black substrate has a notch that connects the through hole to an outer surface.

3. the substrate is a single crystal substrate of a ferroelectric material; 3. The substrate inspection device according to claim 1, wherein the image processing device adjusts contrast of the image obtained by the second imaging device so that an area with a poling defect can be identified.

4. 4. The substrate inspection device according to claim 3, wherein the substrate is a single crystal substrate made of lithium tantalate or lithium niobate.

5. The method includes a first inspection step, a second inspection step, a third inspection step, and an image processing step, The first inspection step includes: a first light irradiation step of irradiating a first surface of a substrate placed on a substrate holder with light from a first light source; a first imaging step of imaging the first surface of the substrate by a first imaging device, The second inspection step includes: a second light irradiation step of irradiating a second surface of the substrate opposite to the first surface with light from a second light source; a second imaging step of imaging the first surface of the substrate by a second imaging device, The third inspection step includes: a third light irradiation step of irradiating the edge of the substrate with light from a third light source; a third imaging step of imaging the edge of the substrate by a third imaging device, A substrate inspection method, wherein the image processing step processes the images obtained in the first imaging step, the second imaging step, and the third imaging step.

6. the substrate is a single crystal substrate of a ferroelectric material; 6. The substrate inspection method according to claim 5, wherein said image processing step adjusts contrast of the image obtained in said second imaging step so that regions of poling defects can be identified.

7. 7. The substrate inspection method according to claim 6, wherein the substrate is a single crystal substrate made of lithium tantalate or lithium niobate.

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