Hole inspection system and method

Abstract

The present invention relates to a hole inspection system and method and, more specifically, to a system and method for inspecting the shape and position of a through-hole formed in a substrate. According to an embodiment, the hole inspection system for a substrate having a hole comprises: a substrate support device which supports a substrate; a camera disposed above or below the substrate to obtain an image of the substrate; a light source disposed on the same side as the camera relative to the substrate; a reflective plate disposed on the other side to the camera; and an inspection module which inspects a hole on the basis of the image of the substrate obtained by the camera, wherein the image of the substrate may be generated on the basis of light that has passed through the inner diameter of the hole and been reflected by the reflective plate, light reflected from an area exterior to the outer diameter of the hole, and light reflected or scattered in the area between the outer diameter of the hole and the inner diameter of the hole.

Description

Hole inspection system and method

[0001] The present invention relates to a hole inspection system and method, and more particularly, to a system and method for inspecting the shape and position of a through hole formed in a substrate.

[0002] To improve device integration, next-generation PIM (Processing In Memory) semiconductors are being developed, utilizing large-area glass substrates. To this end, systems and methods for inspecting through-holes formed in the substrate are needed.

[0003] In this regard, Japanese registration number 3859446, “Semiconductor substrate inspection device and semiconductor substrate inspection method”, discloses a technology for inspecting through holes by sequentially applying multiple direct current voltages, each having a different voltage value, to a semiconductor substrate.

[0004] This existing technology is a technique that can be applied after processing a conductor into a through hole, but has the limitation of being insufficient for inspection of the through hole itself, such as the shape or location of the through hole.

[0005] Meanwhile, the background technology described above is technical information that the inventor possessed for the purpose of deriving the present invention or acquired during the process of deriving the present invention, and cannot necessarily be said to be publicly known technology disclosed to the general public prior to the application for the present invention.

[0006] The problem to be solved by the present invention is to shorten the inspection time and improve accuracy when inspecting a hole formed on a substrate.

[0007] The problem to be solved by the present invention is to accurately and quickly perform inspection when inspecting at least one of the inner diameter, outer diameter, and position of a hole formed on a substrate.

[0008] The problem that the present invention seeks to solve is to construct a low-cost, high-efficiency system for inspecting holes formed on a substrate.

[0009] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] According to one embodiment of the present invention for solving the above-described problem, a hole inspection system for a substrate having a hole includes a substrate support device for supporting the substrate, a camera disposed above or below the substrate to obtain an image of the substrate, a light source disposed on the same side as the camera with respect to the substrate, a reflector disposed on the other side of the camera, and an inspection module for inspecting the hole based on the image of the substrate obtained by the camera, wherein the image of the substrate is generated based on light reflected by the reflector through the inner diameter of the hole, light reflected in an area outside the outer diameter of the hole, and light reflected or scattered in an area between the outer diameter of the hole and the inner diameter of the hole.

[0011] Additionally, according to one embodiment of the present invention, in the hole inspection system, the reflector may have an area corresponding to the entire area of ​​the substrate.

[0012] Additionally, according to one embodiment of the present invention, in the hole inspection system, the reflector may have a width corresponding to the width of the substrate and a length corresponding to the FOV of the camera.

[0013] Additionally, according to one embodiment of the present invention, in the hole inspection system, the reflector may be spaced apart from the substrate by a distance of 0.5 mm or more and 170 mm or less.

[0014] Additionally, according to one embodiment of the present invention, in the hole inspection system, the reflector may have a reflectivity of 60% or more.

[0015] Additionally, according to one embodiment of the present invention, in the hole inspection system, the reflector may be formed by being plated with aluminum or chrome.

[0016] Additionally, according to one embodiment of the present invention, in the hole inspection system, the light source can emit straight light as a coaxial light source with respect to the camera.

[0017] Additionally, according to one embodiment of the present invention, in the hole inspection system, the camera obtains an image of the substrate including the inner and outer diameters of the hole simultaneously, and the inspection module can determine whether the hole is a good product based on the image of the substrate.

[0018] Additionally, according to one embodiment of the present invention, in the hole inspection system, the image of the substrate may have a gray level difference of 10 or more between the inside and outside of the boundary area of ​​the inner diameter.

[0019] In addition, according to one embodiment of the present invention, a hole inspection method performed by a hole inspection system may include a step of illuminating the substrate with a light source disposed on the same side as a camera and a reflector reflecting light emitted by the light source, a step of obtaining an image of the substrate using the camera, wherein the image of the substrate is generated based on light reflected by the reflector through an inner diameter of the hole, light reflected in an area outside the outer diameter of the hole, and light reflected or scattered in an area between the outer diameter of the hole and the inner diameter of the hole, and a step of inspecting the hole based on the obtained image of the substrate.

[0020] According to any one of the problem solving means of the present invention, when inspecting a hole formed on a substrate, the inspection time can be shortened and the accuracy can be improved.

[0021] According to any one of the problem solving means of the present invention, it is possible to accurately and quickly perform inspection when inspecting at least one of the inner diameter, outer diameter, and position of a hole formed on a substrate.

[0022] According to any one of the problem solving means of the present invention, a low-cost, high-efficiency system can be constructed for inspecting holes formed on a substrate.

[0023] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0024] Figure 1 is a cross-sectional view showing an example of a through hole.

[0025] FIG. 2 is an exemplary diagram of an image of a substrate according to one embodiment of the present invention.

[0026] FIG. 3 is a side view illustrating a hole inspection system according to one embodiment of the present invention.

[0027] FIG. 4 is an exemplary diagram of a substrate having a plurality of holes according to one embodiment of the present invention.

[0028] FIG. 5 is a top view illustrating a hole inspection system according to one embodiment of the present invention.

[0029] FIG. 6 is an exemplary diagram illustrating a hole inspection system according to another embodiment.

[0030] Figure 7 is a flowchart for explaining a hole inspection method according to one embodiment of the present invention.

[0031] FIG. 8 is an image of one hole among images of a substrate according to one embodiment of the present invention.

[0032] Figure 9 is a graph showing the degree of change in gray level for holes in the image of the substrate of Figure 8 according to the distance between the substrate and the reflector and the type of reflector.

[0033] The advantages and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In other words, the present invention is defined solely by the scope of the claims.

[0034] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are exemplary, and therefore the present invention is not limited to the matters illustrated. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. When the terms “includes,” “has,” and “consists of” are used in this specification, other parts may be added unless “only” is used. When a component is expressed in the singular, it includes a case where the plural is included unless there is a specifically explicit description.

[0035] When interpreting components, it is interpreted as including the error range even if there is no separate explicit description.

[0036] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a "first" component referred to below may also be a "second" component within the technical scope of the present invention.

[0037] Unless otherwise specified, the same reference numerals refer to the same components throughout the specification.

[0038] The individual features of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and as can be fully understood by those skilled in the art, various technical connections and operations are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship.

[0039] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[0040] First, Fig. 1 is a cross-sectional view illustrating an example of a through hole (20) formed in a substrate (10). Referring to Fig. 1, according to an embodiment, the cross-section of the hole (20) includes an upper diameter (21a) and a lower diameter (21b), and may include a waist diameter (22a). In addition, each hole (20) may be spaced apart by a certain distance, and in this case, the distance (23) between the holes (20) may be defined as the distance between the centers of the holes (20).

[0041] According to FIG. 1, the cross-section of the hole (20) formed in the substrate (10) may be formed in an hourglass shape with wide ends and a narrow center, but may be implemented in various shapes depending on the embodiment, such as a tapered shape or a cylindrical shape.

[0042] In addition, FIG. 2 is an exemplary diagram of an image of a substrate (10) according to one embodiment of the present invention. Referring to FIG. 2, the image of the substrate (10) observed from the upper or lower portion of the substrate (10) includes an image of a hole (20). According to FIG. 2, the hole (20) is implemented in a circular shape, but may be implemented in various shapes, such as an oval or a square, depending on the embodiment.

[0043] Referring to FIGS. 1 and 2, the upper diameter (21a) and the lower diameter (21b) of the hole (20) correspond to the upper and lower outer diameters (21) of the hole (20). In addition, the waist diameter (22a) of the hole (20) corresponds to the inner diameter (22) of the hole (20). At this time, the substrate (10) can be divided into an outer region of the outer diameter (21), a tapered region between the outer diameter (21) and the inner diameter (22), and a pupil region inside the inner diameter (22) based on the hole (20). At this time, since the reflectivity for the irradiated light is different due to the influence of the morphological characteristics of each region, a system for identifying and inspecting the inner and outer diameters (21, 22) of the hole (20) is disclosed.

[0044] In relation to this, FIG. 3 is an exemplary diagram for explaining a hole inspection system (100) according to one embodiment of the present invention. Referring to FIG. 3, the hole inspection system (100) is for inspecting a hole (20) formed in a substrate (10), and can inspect, for example, a plurality of through holes (20) formed in a large-area glass substrate (10) for a PIM semiconductor.

[0045] According to one embodiment, a hole inspection system (100) may include a substrate support device (110) that supports a substrate (10), a camera (120) that is positioned above or below the substrate (10) and obtains an image of the substrate (10), a light source (130) that illuminates the substrate (10), a reflector (140) that reflects light emitted by the light source (130), and an inspection module (150) that inspects a hole (20) based on an image obtained by the camera (120).

[0046] At this time, the substrate support device (110) is configured to support the substrate (10) by coming into contact with the substrate (10) while performing hole (20) inspection, and according to an embodiment, the substrate (10) can be supported on both sides of the substrate (10), and for example, the edge area of ​​the substrate (10) where the hole (20) is not arranged can be supported.

[0047] According to an embodiment, the substrate support device (110) may include a substrate movement module (111), and the substrate movement module (111) may move the substrate (10) according to the process. Specific details regarding the movement of the substrate (20) will be described later in the relevant section.

[0048] Next, the camera (120) is configured to be placed on the upper or lower side of the substrate (10) to obtain an image of the substrate (10). Referring to FIG. 3, an embodiment in which the camera (120) is placed on the upper side of the substrate (10) is illustrated.

[0049] In this regard, the camera (120) may be configured as a line scan camera, for example, a TDI line scan camera, and thus, an image of the substrate (10) can be quickly scanned and acquired. In this regard, the camera (120) may be moved by the camera movement module (160) to acquire an image of the entire area of ​​the substrate (10). To this end, the camera movement module (160) supports the camera (120) at a predetermined distance from the substrate (10) and may move the camera (120) as the process progresses.

[0050] At this time, the camera (120) must obtain an image of the substrate (10) including an image of a hole (20) sufficient to inspect the shape, location, etc. of the hole (20). Specifically, in order to identify and inspect the inner and outer diameters (21, 22) of the hole (20), an image of the substrate (10) in which the gray levels inside and outside the boundary area of ​​the inner and outer diameters (21, 22) differ by 10 or more must be obtained. Here, the gray level refers to a value obtained by dividing the brightness of each pixel on the image into 256 gray levels from 0 to 255 when the image of the substrate obtained through the camera (120) is digitized.

[0051] That is, the hole inspection system (100) can inspect the inner diameter (22) by acquiring an image of the substrate (10) in which the gray levels inside and outside the boundary area of ​​the inner diameter (22) differ by 10 or more, and can inspect the outer diameter (21) by acquiring an image of the substrate (10) in which the gray levels inside and outside the boundary area of ​​the outer diameter (21) differ by 10 or more.

[0052] Therefore, the hole inspection system (100) can adjust the brightness of the light source (130), the type of reflector (140) that affects the reflectivity, and the gap between the reflector (140) and the substrate (10) to obtain an image in which the gray levels inside and outside the boundary area of ​​the inner diameter (22) differ by 10 or more.

[0053] That is, the hole inspection system (100) may include a light source (130) and a reflector (140) considering such conditions. At this time, the light source (130) is configured to illuminate the substrate (10) and is positioned on the same side as the camera (120) with respect to the substrate (10), and may be positioned above or below the substrate (10) depending on the position of the camera (120). Depending on the embodiment, the light source (130) may be implemented as a coaxial light source with respect to the camera (120) and may provide light with strong straightness.

[0054] Additionally, the reflector (140) reflects the light emitted by the light source (130) and can be placed on the other side of the camera (120) with respect to the substrate (10).

[0055] For example, when the camera (120) is placed on the upper part of the substrate (10) as in FIG. 3, the light source (130) is placed on the upper part of the substrate (10) to provide coaxial light for the camera (120) to the substrate (10), and the reflector (140) is placed on the lower part of the substrate (10) on the other side of the camera (120) with respect to the substrate (10) to reflect the light emitted by the light source (130) toward the substrate (10).

[0056] The reflector (140) according to the embodiment can reflect the light of the light source (130) toward the substrate so that the gray levels inside and outside the inner diameter of the hole differ by 10 or more in the image of the substrate acquired through the camera (120).

[0057] To this end, the reflector (140) has a predetermined reflectivity capable of reflecting sufficient light so that the gray levels inside and outside the inner diameter of the hole in the substrate image differ by 10 or more. For example, the predetermined reflectivity may be 60% or more. Here, the reflectivity refers to the ratio of the amount of reflected light to the amount of incident light, and may include one or more of visible light, infrared (IR), ultraviolet (UV), etc., depending on the wavelength that the camera (120) can respond to, and may be, for example, the ratio of the amount of incident light to the amount of reflected light for visible light. In addition, according to an embodiment, since the light source (130) provides a coaxial light source with respect to the camera to the substrate (10), in the embodiment of the present invention, the ratio of the amount of reflected light to the amount of incident light that is vertically incident can be assumed as the reflectivity.

[0058] According to an embodiment, the reflector (140) may be formed of one of glass, ceramic, quartz, acrylic, polypropylene, polyimide, and PET having light transmittance and light reflectance, or may be formed of a metal surface having light blocking properties and light reflectance, in order to have a predetermined reflectance. For example, the reflector may include one or more of silicon (Si), chromium (Cr), aluminum (Al), gold (Au), silver (Ag), titanium (Ti), zirconium (Zr), tungsten (W), molybdenum (Mo), platinum (Pt), copper (Cu), and zinc (Zn) as the material of the reflector or as a coating material, and may preferably be formed by being plated with either chromium or aluminum. When the reflector (140) is formed by being plated with 1000 A (Angstrom) of chromium, it may have a reflectance of about 60%, and when it is formed by being plated with aluminum, it may have a reflectance of about 90%.

[0059] In addition, the reflector (140) may be spaced apart from the substrate (10) by a predetermined distance so that the reflected light can be sufficiently collected by the camera (120) so that the gray levels inside and outside the inner diameter (22) of the hole (20) in the image of the substrate (10) can differ by 10 or more. For example, the reflector (140) may be spaced apart by a distance of 170 mm or less. Specifically, in the case of an aluminum reflector (140) with a reflectivity of 90%, when spaced apart by a distance of 170 mm or less, an image in which the gray levels inside and outside the inner diameter (22) differ by 10 or more can be obtained for inspection, and in the case of a chrome reflector (140) with a reflectivity of 60%, when spaced apart by a distance of 130 mm or less, an image in which the gray levels inside and outside the inner diameter (22) differ by 10 or more can be obtained for inspection.

[0060] Additionally, according to an embodiment, the reflector (140) may be spaced apart from the substrate (10) by a predetermined distance so as not to interfere with the movement of the substrate (10). For example, the reflector (140) may be spaced apart from the substrate (10) by 0.5 mm or more.

[0061] Accordingly, the reflector (140) may be placed at a distance of 0.5 mm or more and 170 mm or less with respect to the substrate (10). If the gap between the reflector (140) and the substrate (10) is 170 mm or more, the reflected light spreads and the resolution deteriorates. If the gap between the reflector (140) and the substrate (10) is smaller, a clearer image can be obtained, particularly, an image in which the pupil inside the hole (20) is clear. In addition, if the gap between the reflector (140) and the substrate (10) is less than 0.5 mm, the reflector (140) and the substrate (10) may be damaged due to contact with the reflector (140) during the transport process of the substrate (10).

[0062] According to an embodiment, in order to obtain an image of a substrate (10) in which the gray levels inside and outside the boundary area of ​​the inner diameter (22) differ by 10 or more, the gap between the reflector (140) and the substrate (10) should be closer as the reflectivity of the reflector (140) decreases, and it is necessary to have a gap that prevents the substrate (10) and the reflector (140) from being damaged by interference. Based on this, it is preferable that the hole inspection system (100) arranges a reflector (140) having a reflectivity of 60% or more with a gap of 0.5 mm or more and 170 mm or less from the substrate (10).

[0063] According to the configuration of the light source (130) and the reflector (140) as described above, an optical image can be formed based on the light emitted from the light source (130) penetrating the inner diameter of the hole and reflected by the reflector (140), the light reflected in the outer region of the outer diameter of the hole, and the light reflected or scattered in the region between the outer diameter and the inner diameter of the hole (e.g., a tapered region). At this time, optical phenomena such as the light emitted from the light source (130) and reflected along different paths and entering the camera interfering with each other or diffracting while passing through the hole (20) can participate in the creation of the optical image.

[0064] According to an embodiment, the hole inspection system (100) can simultaneously inspect the inner and outer diameters (21, 22) by acquiring an image of the substrate (10) in which the gray levels of the inner and outer boundaries of each boundary line of the inner and outer diameters (21, 22) differ by 10 or more, particularly, the boundary line of the inner diameter (22). Through this, the hole inspection system (100) can shorten the inspection time and improve the accuracy of the inspection.

[0065] Meanwhile, the inspection module (150) inspects the hole (20) based on the image acquired by the camera (120), and may include a processor for image analysis. According to an embodiment, the inspection module (150) may extract the boundary lines of the inner and outer diameters (21, 22) and inspect whether the inner and outer diameters (21, 22) of the hole (20) are formed and the shape of the inner and outer diameters (21, 22), thereby determining whether the hole (20) is a good product. According to an embodiment, the inspection module (150) may process the image of the substrate (10) to increase the difference in gray levels inside and outside the boundary line area of ​​the inner and outer diameters (21, 22) in order to make the boundary lines of the inner and outer diameters (21, 22) clearer.

[0066] In addition, the inspection module (150) can measure the distance between holes (20) to determine whether the holes (20) are of good quality. For example, the center of the holes (20) is determined based on at least one of the inner diameter (22) and the outer diameter (21), and the distance (23) between the holes (20) is measured based on the center of each hole (20) to analyze the alignment state of the holes (20), thereby determining whether the holes (20) are of good quality.

[0067] In this regard, FIG. 4 is an exemplary diagram of a substrate (10) having a plurality of holes (20) according to one embodiment of the present invention. According to FIG. 4, the substrate (10) may form global marks (41, 42, 43) corresponding to a point of the substrate (10), for example, a corner of the substrate (10), and alignment marks (50) corresponding to each corner of a group (30) formed by a plurality of holes (20), or may be fixed with separate coordinate configurations forming the global marks (41, 42, 43) and the alignment marks (50). For example, when a group (30) formed by a plurality of holes (20) forms a square, the alignment marks (50) may be formed at positions corresponding to four corners of the group (30).

[0068] Accordingly, the inspection module (150) can measure the relative position of the alignment mark (50) based on the global mark (41, 42, 43), and can measure the position of each hole (20) included in a group (30) based on the alignment mark (50).

[0069] According to an embodiment, the global marks (41, 42, 43) and the alignment marks (50) may be formed by a plurality of points or circles arranged radially. For example, the global marks (41, 42, 43) and the alignment marks (50) may be formed by a point or circle arranged in the center, and a plurality of points or circles arranged at equal intervals in all directions around the point or circle arranged in the center.

[0070] In this regard, the inspection module (150) may include an image processing unit (not shown) that processes an image of the substrate (10) based on the global marks (41, 42, 43) and the alignment marks (50).

[0071] According to an embodiment, the image processing unit can determine whether the image of the substrate (10) is distorted based on the global marks (41, 42, 43) and the alignment marks (50). That is, the position and spacing of the global marks (41, 42, 43) and the alignment marks (50), the distortion of the points or circles included in the global marks (41, 42, 43) and the alignment marks (50) are measured, or the sizes of the points or circles included in the global marks (41, 42, 43) and the alignment marks (50) are compared, and based on this, distortion such as tilting or distortion of the image can be determined and corrected.

[0072] At this time, the image processing unit can perform an affine transformation that changes the entire image by changing the arrangement of pixels included in the image. For example, based on the global marks (41, 42, 43) and the alignment mark (50), the distortion such as tilt or distortion of the image can be determined, and the degree of distortion can be measured and corrected by changing the position of each pixel included in the image to translate or rotate the image, and the distortion can be corrected by converting the size of the image or adjusting the ratio of the image.

[0073] In addition, when the camera (120) acquires multiple images of a single substrate (10) divided into predetermined areas, the image processing unit can acquire an image of the entire substrate (10) by merging the multiple images divided based on the global marks (41, 42, 43) and the alignment marks (50). For example, the image processing unit can merge the multiple images by determining the relative positions between the multiple images based on the global marks (41, 42, 43) and the alignment marks (50).

[0074] In addition, the image processing unit may perform affine transformation on each of the plurality of images divided based on the global marks (41, 42, 43) and the alignment mark (50) and merge them. At this time, the image processing unit may perform affine transformation on each of the plurality of divided images and merge them to match the CAD. At this time, the CAD is a general term for the CAD file itself, the CAD image converted from the CAD file, and the data extracted from the CAD file or the CAD image. The data extracted from the CAD file or the CAD image includes, for example, information that can confirm the relative positions between the plurality of divided images, and as an example, may include coordinate information of the global marks (41, 42, 43) and the alignment mark (50) included in the CAD file or the CAD image. Accordingly, the image processing unit performs affine transformation so that the global marks (41, 42, 43) and alignment marks (50) included in the multiple images match the global marks (41, 42, 43) and alignment marks (50) included in the CAD, and merges them to obtain an image of the entire substrate (10).

[0075] Through this, the inspection module (150) can determine whether the hole (20) is a good product based on the image of the substrate (10). For example, the inspection module (150) can determine whether the position of the hole (20) is suitable based on the entire image of the substrate (10). Specifically, the inspection module (150) can inspect the position of a group (30) formed by a plurality of holes (20) based on the entire image of the substrate (10). At this time, the inspection of the position of a group (30) formed by a plurality of holes (20) may include an inspection of the alignment state of a group (30) formed by a plurality of holes (20), such as the position where a group (30) formed by a plurality of holes (20) is formed within the substrate (10), the distance between the groups (30), and the relative direction of the group (30) with respect to the global mark (41, 42, 43).

[0076] Specifically, the inspection module (150) inspects the position of each hole (20) included in a group (30) formed by a plurality of holes (20). The inspection module (150) assigns coordinates to each hole (20) based on alignment marks (50) corresponding to each corner of the group (30) and inspects the position of each hole (20) based on the assigned coordinates. In addition, the inspection module (150) extracts a direction component for a group (30) formed by a plurality of holes (20) based on the alignment marks (50) and extracts a relative direction of the extracted direction component with respect to global marks (41, 42, 43), thereby inspecting the alignment state of a group (30) formed by a plurality of holes (20).

[0077] Next, FIG. 5 is a top view illustrating a hole inspection system (100) according to one embodiment of the present invention.

[0078] Referring to FIG. 5, the substrate (10) can be moved by the substrate movement module (111), and the camera (120) can be moved by the camera movement module (160) to obtain an image of the substrate (10). In addition, a reflector (140) can be placed on the other side of the camera (120) with respect to the substrate (10), and at this time, the reflector (140) can be placed on a vertical line with the camera (120).

[0079] Specifically, the camera movement module (160) can reciprocate the camera (120) in a first direction (x1) parallel to the substrate (10). In addition, the substrate movement module (111) can move the substrate (10) in a second direction (x2) parallel to the substrate (10) but perpendicular to the first direction (x1). To this end, the substrate movement module (111) may include a plurality of linear drive modules (not shown) arranged on each side of the substrate (10) to move the substrate (10). Accordingly, the camera (120) can acquire a plurality of images by dividing one substrate (10) into predetermined regions, and as a result, can quickly and simply acquire an image for the entire region of the substrate (10). In addition, in order to continuously provide a coaxial light source while the camera (120) moves, the light source (130) can move together with the camera (120) by the camera movement module (160).

[0080] At this time, the reflector (140) may be installed to extend parallel to the first direction (x1) in which the camera (120) reciprocates. In addition, the reflector (140) may be placed perpendicular to the camera (120).

[0081] According to an embodiment, the reflector (140) may have a width corresponding to the width of the substrate (10) and a length corresponding to the FOV (Field of View) of the camera (120). Here, the FOV refers to the angle of view of the camera (120).

[0082] At this time, the width corresponding to the width of the substrate (10) may be a length corresponding to either the horizontal width or the vertical width of the substrate (10) or the area where the hole (20) is formed on the substrate (10), and depending on the embodiment, may be the width of the substrate (10) in a direction parallel to the first direction (x1) in which the camera (120) reciprocates on the substrate (10) or the width of the area where the hole (20) is formed on the substrate (10) in a direction parallel to the first direction (x1).

[0083] In addition, the length corresponding to the FOV of the camera (120) refers to the length corresponding to the area on the substrate (10) that the camera (120) can photograph at one time according to the FOV of the camera (120), and for example, it may be the length in the direction parallel to the second direction (x2) of the area on the substrate (10) that the camera (120) can photograph at one time according to the FOV of the camera (120).

[0084] As described above, since the reflector (140) has a width corresponding to the width of the substrate (10) and a length corresponding to the FOV of the camera (120), the reflector (140) can illuminate an area of ​​the substrate (10) corresponding to an image acquired by the camera (120) as it reciprocates.

[0085] In another embodiment, the reflector (140) may be formed with an area corresponding to the entire area of ​​the substrate (10). For example, it may be formed with the same area as the substrate (10) to provide reflected light for the entire substrate (10).

[0086] In this regard, FIG. 6 is an exemplary diagram for explaining a hole inspection system (100) according to another embodiment. In the hole inspection system (100) illustrated in FIG. 6, some of the configurations that are identical to those illustrated in FIGS. 3 and 5, or their descriptions, are omitted.

[0087] Referring to Fig. 6, the reflector (140) can be formed as a large-area reflector (340) corresponding to the entire area of ​​the substrate (10). At this time, the large-area reflector (340) can be fixed to the substrate (10) by a reflector support member (370) with a predetermined distance between the substrate (10) and the reflector support member.

[0088] At this time, the substrate support device (310) can support the substrate (10) and the large-area reflector (340) together. For example, when the large-area reflector (340) and the substrate (10) are bonded together and the large-area reflector (340) is positioned below the substrate (10), the substrate (10) and the large-area reflector (340) can be supported together by supporting the large-area reflector (340).

[0089] And the substrate movement module (311) can also move the substrate (10) and the large-area reflector (340) together. That is, when the substrate (10) and the large-area reflector (340) are fixed while forming a gap of a predetermined distance, the substrate movement module (311) can move the substrate (10) and the large-area reflector (340) together.

[0090] In this case, the substrate support device (310) supports the substrate (10) and the large-area reflector (340) at the lower center of the large-area reflector (340), and the substrate movement module (311) is formed by including one linear driving module (not shown) that crosses the lower center of the large-area reflector (340), thereby enabling the substrate (10) and the large-area reflector (340) to move together. This has the advantage of lowering the manufacturing cost of the equipment and reducing maintenance costs.

[0091] Next, FIG. 7 is a flowchart for explaining a hole inspection method according to one embodiment of the present invention.

[0092] Referring to FIG. 7, the hole inspection method performed by the hole inspection system (100) can illuminate the substrate (10) by a light source (130) placed on the same side as the camera (120) with respect to the substrate (10) and a reflector (140) that reflects the light emitted by the light source (130) (S710).

[0093] At this time, the camera (120) is placed on the upper or lower side of the substrate (10) to obtain an image of the substrate (10), and the light source (130) can provide a coaxial light source for the camera (120) to the substrate (10). In addition, the reflector (140) can be placed on the other side of the camera (120) with respect to the substrate (10) to reflect the light emitted from the light source (130) toward the substrate (10).

[0094] According to an embodiment, the reflector (140) has an area corresponding to the entire area of ​​the substrate (10), thereby providing reflected light for the entire area of ​​the substrate (10). According to another embodiment, the reflector (140) has a width corresponding to the width of the substrate (10) and a length corresponding to the FOV of the camera (120), thereby providing reflected light for an area corresponding to an image acquired by the camera (120) while moving back and forth.

[0095] And the reflector (140) can be arranged at a distance of 0.5 mm or more and 170 mm or less with respect to the substrate (10). According to an embodiment, when the gap between the reflector (140) and the substrate (10) is 170 mm or more, the reflected light by the reflector (140) spreads, so that the resolution of the image of the hole (20), particularly, the image of the pupil inside the hole (20), is reduced, and the inner diameter (22) of the hole (20) cannot be detected. In addition, when the gap between the reflector (140) and the substrate (10) is 0.5 mm or less, there is a possibility of damage due to contact between the reflector (140) and the substrate (10). Therefore, it is preferable that the reflector (140) be placed at a distance of 0.5 mm or more and 170 mm or less from the substrate (10), and this can be adjusted according to the intensity of the light source (130) and the reflectivity according to the material of the reflector (140).

[0096] For example, the reflector (140) is preferably positioned with a reflectivity of 60% or more, and in the case of an aluminum reflector (140) having a reflectivity of about 90% according to an embodiment, it may be positioned at a distance of 162.5 mm or less from the substrate (10). In addition, in the case of a chrome reflector (140) having a reflectivity of about 60%, it is preferably positioned at a distance of 127.5 mm or less from the substrate (10). By adjusting the reflectivity of the reflector (140) and the distance between the reflector (140) and the substrate (10) in this way, an image of the substrate (10) suitable for hole (20) inspection can be obtained.

[0097] According to an embodiment, the hole inspection system (100) can obtain an image of the substrate (10) using a camera (120) (S720).

[0098] At this time, the image of the substrate (10) can be generated based on the light reflected by the reflector (140) through the inner diameter (22) of the hole (20), the light reflected in the area outside the outer diameter (21) of the hole (20), and the light reflected or scattered in the area (e.g., tapered area) between the outer diameter (21) of the hole (20) and the inner diameter (22) of the hole (20). At this time, the light emitted from the light source (130), the light reflected through the reflector (140), and the light reflected through different paths and incident on the camera (120) can cause optical phenomena such as diffraction or interference with each other as they pass through the hole (20), and can participate in the generation of the image.

[0099] And the hole inspection system (100) can inspect the hole (20) based on the image of the acquired substrate (10) (S730).

[0100] At this time, the gray levels inside and outside the boundary area of ​​the inner diameter (22) of the hole (20) in the image of the substrate (10) may differ by 10 or more. That is, when the gray levels inside and outside the boundary area of ​​the inner and outer diameters (21, 22) of the hole (20) have a difference of 10 or more, the inner and outer diameters (21, 22) can be detected, and for this purpose, the reflectivity of the reflector (140) and the gap between the reflector (140) and the substrate (10) can be adjusted. In addition, according to an embodiment, the gray levels inside and outside the boundary area of ​​the inner and outer diameters (21, 22) can have a difference of 10 or more through correction of the image of the substrate (10).

[0101] According to an embodiment, the hole inspection system (100) can process an image of the substrate (10) based on global marks (41, 42, 43) corresponding to a point of the substrate (10) and alignment marks (50) corresponding to each corner of a group (30) formed by holes (20).

[0102] At this time, the global marks (41, 42, 43) and the alignment marks (50) may be formed on the substrate (10) itself by radially arranging multiple points or circles, and may be formed in a separate coordinate configuration and attached to the substrate (10) according to an embodiment.

[0103] According to an embodiment, the hole inspection system (100) can determine whether the image of the substrate (10) is distorted based on the global marks (41, 42, 43) and the alignment mark (50), correct the image of the substrate (10), and inspect whether the hole (20) is good based on the corrected image of the substrate (10).

[0104] For example, the hole inspection system (100) can inspect at least one of the positions of a group (30) formed by a plurality of holes (20) and the positions of each hole (20) included in the group (30) based on the global marks (41, 42, 43) and the alignment marks (50).

[0105] In addition, the hole inspection system (100) can acquire an image of the entire substrate (10) by merging multiple images divided into predetermined areas acquired through a camera (120) based on global marks (41, 42, 43) and alignment marks (50).

[0106] For example, the hole inspection system (100) can perform affine transformation on a plurality of images divided based on global marks (41, 42, 43) and alignment marks (50), and merge them to match CAD to obtain an image of the entire substrate (10).

[0107] The hole inspection system (100) of the present invention moves the line camera back and forth in the first direction (x1) while moving the substrate (10) in the second direction (x2) to obtain an image of the entire substrate (10), so that the inspection time is shortened and inspection is easily possible regardless of the size of the substrate (10) that is input.

[0108] (Experimental example)

[0109] According to an embodiment of the present invention, as described above, the hole inspection system (100) must acquire an image in which the difference in gray levels of each of the area inside and outside the outer diameter (21) of the hole (20) and the area inside and outside the inner diameter (22) of the hole (20) on the image of the substrate (20) is 10 or more in order to identify and inspect the inner and outer diameters (21, 22) of the hole (20) formed on the substrate (10). To this end, the hole inspection system (100) according to the embodiment can adjust the type of reflector (140) that affects the reflectivity and the gap between the reflector (140) and the substrate (10), and an experimental example related thereto will be described with reference to FIGS. 8 and 9.

[0110] First, Fig. 8 is an image of one hole (20) among the images of the substrate (10) according to one embodiment of the present invention. Fig. 8 shows A1, a point where the outer diameter (21) meets the hole (20), and A2 and A3, points where the inner diameter (22) meets the hole (20), on an arbitrary straight line passing through the center of the hole (20).

[0111] And FIG. 9 is a graph showing the degree of change in the gray level for a hole in the image of the substrate of FIG. 8 according to the separation distance and type of the reflector. Specifically, FIG. 9 is a graph showing the degree of change in the gray level for a hole (20) in the image of the substrate (10) according to the separation distance between the substrate (10) and the reflector (140), and is a graph created for each reflector (140) showing the gray level that changes along an arbitrary straight line passing through the center of the hole (20) as in the embodiment shown in FIG. 8. According to FIG. 9, for each of an aluminum (Al) reflector, a chrome (Cr) reflector, and a glass reflector, an image of the substrate (10) according to the separation distance of the reflector (140) is acquired, and experimental values ​​for measuring the gray level that changes along an arbitrary straight line passing through the center of the hole (20) in each image are shown.

[0112] According to each graph included in Fig. 9, it can be confirmed that the graph sharply drops at point A1, which corresponds to the inside and outside of the boundary area of ​​the outer diameter (21), and sharply rises at point A2, which corresponds to the inside and outside of the boundary area of ​​the inner diameter (22), forming a constant gray level up to point A2-A3, which corresponds to the pupil area inside the boundary area of ​​the inner diameter (22).

[0113] Specifically, when examining the experimental value 1 of Fig. 9, the distance between the substrate (10) and the reflector (140) is 162.5 mm, and at this time, it was confirmed that the difference in gray levels near A1 and near A2 of the aluminum reflector was more than 10. On the other hand, in the case of the chrome reflector and the glass reflector, the difference in gray levels is less than 10. That is, when the aluminum reflector and the substrate (10) having a reflectivity of about 90% have a gap of about 162.5 mm, it is possible to identify the inner diameter (22) based on the image acquired.

[0114] In addition, when examining the experimental value 2 of Fig. 9, the distance between the substrate (10) and the reflector (140) is 127.5 mm, and at this time, it was confirmed that the difference in gray levels near A1 and near A2 of the aluminum reflector and the chrome reflector was more than 10. On the other hand, in the case of the glass reflector, the difference in gray levels is less than 10. That is, in the case of the chrome reflector having a reflectivity of about 60%, the inner diameter (22) can be identified in the acquired image when there is a gap of about 127.5 mm.

[0115] Next, when examining the experimental value 3 of FIG. 9, the distance between the substrate (10) and the reflector (140) is 92.5, and when compared to the experimental values ​​1 and 2, it can be seen that the difference in gray levels near A1 and near A2 for both the aluminum reflector and the chrome reflector increases. That is, as the distance between the substrate (10) and the reflector (140) gets closer, the difference in gray levels increases, and a clearer image of the substrate (10) can be obtained.

[0116] And when examining the experimental value 4 of Fig. 9, the distance between the substrate (10) and the reflector (140) is 3 mm, and it is confirmed that the gray levels corresponding to the aluminum reflector, the chrome reflector, and the glass reflector all increase significantly. In this case, the inner diameter (22) can be identified even with a glass reflector having a reflectivity of about 7% because the difference in gray levels near A1 and near A2 is 10 or more, but when the distance between the substrate (10) and the reflector (140) is 0.5 mm or less, damage to the substrate (10) and the reflector (140) may occur, which is not desirable.

[0117] In summary of this experimental example, it can be seen that it is preferable that the hole inspection system (100) be equipped with a reflector (140) having a reflectivity of 60% or more, and at this time, it is preferable that the distance between the substrate (10) and the reflector (140) be spaced by a distance of 0.5 mm or more and 170 mm or less.

[0118] Through this, the hole inspection system (100) can obtain an image of a substrate (10) in which the gray levels inside and outside the boundary area of ​​the inner diameter (22) of the hole (20) and inside and outside the boundary area of ​​the outer diameter (21) differ by 10 or more through a line scan camera, and through this, the formation, shape, and size of the inner diameter (22) and outer diameter (21) of the hole (20) can be inspected, and by inspecting the outer diameter (21) and inner diameter (22) simultaneously, the inspection speed can be greatly shortened, and the accuracy of the inspection results can be improved.

[0119] Although the embodiments of the present invention have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain it, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and not restrictive. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. In a hole inspection system for a substrate having holes, A substrate support device supporting the above substrate; A camera positioned above or below the substrate to obtain an image of the substrate; A light source positioned on the same side as the camera based on the above substrate; A reflector placed on the other side of the above camera; and A hole inspection system including an inspection module that inspects the hole based on an image of the substrate, wherein the image of the substrate is generated based on light reflected by the reflector through the inner diameter of the hole, light reflected from an area outside the outer diameter of the hole, and light reflected or scattered in an area between the outer diameter of the hole and the inner diameter of the hole.

2. In paragraph 1, The above reflector, A hole inspection system having an area corresponding to the entire area of ​​the above substrate.

3. In paragraph 1, The above reflector, A hole inspection system having a width corresponding to the width of the substrate and a length corresponding to the FOV of the camera.

4. In paragraph 1, The above reflector, A hole inspection system, spaced apart from the above substrate by a distance of 0.5 mm or more and 170 mm or less.

5. In paragraph 1, The above reflector, A hall inspection system with a reflectivity of 60% or more.

6. In paragraph 1, The above reflector, A hole inspection system formed by plating with aluminum or chrome.

7. In paragraph 1, The above light source is, A hole inspection system that emits straight light from a coaxial light source with respect to the above camera.

8. In paragraph 1, The above camera, Obtain an image of the substrate including the inner and outer diameters of the hole simultaneously, The above inspection module, A hole inspection system that determines whether the hole is good or bad based on an image of the substrate.

9. In paragraph 8, The image of the above substrate is, A hole inspection system in which the gray levels inside and outside the boundary area of ​​the above inner diameter differ by 10 or more.

10. A hole inspection method performed by the hole inspection system of Article 1, A step of illuminating the substrate by a light source placed on the same side as the camera and a reflector reflecting light emitted by the light source; A step of obtaining an image of the substrate using the camera, wherein the image of the substrate is generated based on light reflected by the reflector through the inner diameter of the hole, light reflected in an area outside the outer diameter of the hole, and light reflected or scattered in an area between the outer diameter of the hole and the inner diameter of the hole; and A hole inspection method, comprising a step of inspecting the hole based on an image of the acquired substrate.

Images