Micro crack inspection device and inspection method using the same

Abstract

The present invention may provide a microcrack inspection device comprising: a stage (200) for transporting and rotating a substrate (G); an optical unit (100) for scanning a substrate (G) supported by the stage (200); and a control unit (300) for analyzing an image of the substrate (G) scanned by the optical unit (100) to inspect for cracks, wherein the control unit (300) converts the scanned image received from the optical unit (100) into a Difference Map to extract a plurality of candidate defect elements, and detects the presence or absence of microcracks by sequentially removing elements that do not meet the set microcrack conditions from the plurality of candidate defect elements extracted through a plurality of filtering processes.

Description

Technology Field

[0001] The present invention relates to an inspection device for microcracks and an inspection method using the same. Background Technology

[0002] In the case of glass substrates, whether or not there are cracks is often subject to inspection. For example, glass substrates that make up a display panel undergo many processes such as cutting and beveling, slimming, strengthening, cavity formation, and pixel or circuit formation. At each process, there is a possibility that cracks may occur inside the glass substrate, and since cracked glass substrates can degrade the image quality of the display panel, they must be treated as defective.

[0003] Cracks in glass substrates for other uses, as well as in display panels, are mostly treated as quality defects of the glass substrate, and equipment for inspecting cracks in glass substrates has been used, and various types of equipment have been proposed.

[0004] Conventional crack inspection devices, which have been widely used, are equipped with a camera and a light source and detect the occurrence of cracks by irradiating light onto a glass substrate and taking into account that the amount of reflected or transmitted light changes in the cracked area, causing a rapid change in brightness.

[0005] However, conventional crack inspection devices of this type require improvements in accuracy, as they may miss cracks when they occur more finely. Prior art literature

[0006] (Patent Document 0001) KR 10-1127796 B1(2012.03.12) The problem to be solved

[0007] The present invention has been devised to solve the aforementioned conventional problems, and the objective of the present invention is to provide a microcrack inspection device capable of more accurately detecting the presence or absence of cracks generated in a substrate, and an inspection method using the same. means of solving the problem

[0008] The present invention may include the following embodiments to achieve the above objectives.

[0009] An embodiment of the present invention may provide a microcrack inspection device comprising a stage for transporting and rotating a substrate, an optical unit for scanning a substrate supported by the stage, and a control unit for analyzing an image of the substrate scanned by the optical unit to inspect for cracks, wherein the control unit converts the scanned image received from the optical unit into a Difference Map to extract a plurality of candidate defect elements, and sequentially removes elements that do not meet the set microcrack conditions from the plurality of candidate defect elements extracted through a plurality of filtering processes to detect the presence or absence of microcracks.

[0010] In the above embodiment, the microcrack condition may include at least one of the location of the defect element, the scan direction, the shape, and whether the defect elements formed on the upper and lower surfaces are in the same location.

[0011] Additionally, the optical unit may include at least one of a first optical system that scans the upper surface of a substrate and a second optical system that scans the lower surface of a substrate, wherein the first optical system includes a first camera that scans the upper surface of a substrate from the upper side of a stage, a first illuminator that illuminates the substrate from the upper side of a stage, and a first backlight that provides backlight to the substrate from the lower side of a stage, and the second optical system may include a second illuminator that illuminates the substrate from the lower side of a stage, a second camera that scans the substrate from the lower side of a stage, and a second backlight that provides backlight to the substrate from the upper side of a stage.

[0012] In addition, the first illuminator can illuminate the substrate in a direction inclined at 25 to 30° relative to the center of the substrate, and the second illuminator can illuminate the substrate in a direction inclined at 12 to 16° relative to the center of the substrate.

[0013] A microcrack inspection device characterized by the control unit calculating a plurality of candidate defect elements, detecting defect elements having a shape set by first filtering, and performing second filtering to detect the directionality of defect elements of the set shape detected through first filtering, and calculating defect elements having a shape with a set directionality.

[0014] In addition, another embodiment of the present invention includes a) a step of moving a substrate supported on a stage in one direction by means of a camera under the control of a control unit to scan the upper and lower surfaces of the substrate, respectively, and b) a step of analyzing the scanned image to detect microcracks and outputting an alarm, wherein step b) may include b-1) a step in which the control unit receives the scanned image received from the camera and converts it into a Difference Map, b-2) a step of detecting a plurality of candidate defect elements in the image converted into a Difference Map, b-3) a step of filtering candidate defect elements that do not correspond to a set microcrack condition, and b-4) a step of outputting an alarm if a crack is detected after filtering.

[0015] Here, step b-3) may include a first filtering step for extracting defect elements according to a set shape from a defect element candidate group and a second filtering step for extracting defect elements having a set directionality from the defect elements extracted in the filtering.

[0016] a) The step may include a-1) a step of inserting a substrate into the stage, a-2) a step of measuring a position pattern marked on the substrate to tilt the orientation angle or position of the camera, s-3) a step of moving the stage to move the substrate to the position where the fixed camera is oriented and a step of first scanning the two edge portions of the substrate with the camera, a-5) a step of rotating the stage by 90°, and a-6) a step of moving the stage in the reverse direction to move the substrate to the position where the fixed camera is oriented and a step of second scanning the two edge portions of the substrate that were not captured during the first scan with the camera. Effects of the invention

[0017] Therefore, the present invention can accurately detect microcracks in a scanned image of a substrate by applying at least one of the conditions such as the shape, direction, location, and identity of the set microcracks, thereby preventing defects in devices to which the substrate is applied. Brief explanation of the drawing

[0018] FIG. 1 is a block diagram illustrating a microcrack inspection device according to the present invention. Figure 2 is a diagram illustrating the first optical system of the optical section. Figure 3 is a diagram illustrating the second optical system of the optical unit. FIG. 4 is a flowchart illustrating a microcrack inspection method according to the present invention. Figure 5 is a diagram illustrating the process of Figure 4. Figure 6 is a flowchart illustrating the crack inspection step of Figure 4. Figure 7 is a diagram illustrating the image conversion process of Figure 6. Figures 8 and 9 are drawings illustrating defect elements of a substrate. Figure 10 is a drawing illustrating an example of a measurement image. Figure 11 is a comparison diagram of visibility according to the beam angle of the lighting fixture. Specific details for implementing the invention

[0019] Although the present invention may be subject to various modifications and may have various embodiments, specific embodiments are to be described in detail by way of illustration in the drawings. This is not intended to limit the present invention to specific embodiments, and it should be understood that any modification, equivalent, or substitution falls within the spirit and scope of the present invention for connecting and / or fixing structures extending in different directions.

[0020] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0021] In this specification, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0023] Hereinafter, preferred embodiments of the inspection device for microcracks and the inspection method using the same according to the present invention will be described in detail with reference to the attached drawings.

[0024] FIG. 1 is a block diagram illustrating a microcrack inspection device according to the present invention.

[0025] Referring to FIG. 1, the microcrack inspection device according to the present invention includes a stage (200) that supports a substrate (G) to be inspected, an optical unit (100) that scans the substrate (G) located on the stage (200), a control unit (300) that controls the optical unit (100) and the stage (200) to determine whether there is a crack, a display (400) that outputs inspection results and processes, and an alarm unit (500) that outputs an alarm.

[0026] The stage (200) can rotate and move in both directions by control, and supports and moves the substrate (G) on the upper and / or lower surface. Here, the stage (200) can fix the substrate (G) through an air suction method and can move in the forward and backward directions in a manner similar to a conveyor. Additionally, the stage (200) can rotate by a set range (e.g., ± 90°) by control of the control unit (300).

[0027] A stage (200) of this type applies known technology, so a detailed description thereof is omitted. Additionally, the stage (200) may be implemented by applying known technology even if it is not the method mentioned above.

[0028] The optical unit (100) may include at least one of a first optical system (110) that scans the upper surface of the substrate (G) and a second optical system (120) that scans the lower surface of the substrate (G). Depending on the type or purpose of the substrate (G), such optical units (100) may be installed entirely in one device or only one of them may be installed.

[0029] For example, the first optical unit (100) and the second optical unit (100) are positioned on the upper and lower sides, respectively, with respect to the stage (200), so that they can simultaneously scan the upper and lower surfaces of the substrate (G).

[0030] Alternatively, if the first optical unit (100) and the second optical unit (100) are installed separately, the upper surface (or lower surface) of the substrate (G) can be scanned first, and then the lower surface (or upper surface) of the substrate (G) can be scanned sequentially.

[0031] This can be selected by the business operator and the designer considering the type of substrate (G) or the installation space. The optical unit (100) is described with reference to FIGS. 2 and FIGS. 3.

[0032] FIG. 2 is a drawing illustrating the first optical system of the optical unit, and FIG. 3 is a drawing illustrating the second optical system of the optical unit.

[0033] Referring to FIGS. 2 and FIGS. 3, the first optical system (110) may include a first illuminator (111), a first camera (112), and a first backlight (113).

[0034] The first illuminator (111) can be installed with a directional angle of 25 to 30° relative to the center of the substrate (G). That is, the first illuminator (111) can illuminate the substrate (G) from a slanted direction of 25 to 30° relative to the center (center) of the substrate (G).

[0035] The first camera (112), for example, as a line scan camera, scans the upper surface of a substrate (G) that is moved in one direction or opposite direction by a stage (200) while maintaining illumination by the first illuminator (111) and a backlight, and outputs a scanned image to the control unit (300).

[0036] At this time, the first camera (112) scans the edge portion of the upper surface of the substrate (G) that is moved and rotated by the stage (200). That is, the first camera (112) scans the edge portion of the substrate to check for the presence or absence of microcracks concentrated at each edge portion of the substrate (G).

[0037] Here, the first camera (112) can rotate and move in the forward and / or left and right directions to scan a substrate (G) supported on the upper part of the stage (200), and can also move up and down in the up and down direction to adjust the scanning distance.

[0038] The first backlight (113) provides backlight illumination on the lower surface of the substrate (G) that is moved by the stage (200). At this time, the stage (200) supports the stage (200) having a width narrower than the width of the substrate (G), as illustrated as an example in the drawing. Therefore, the illumination output from the first backlight (113) can illuminate the lower surface of each side of the substrate (G) supported by the stage (200).

[0039] The second optical system (120) comprises a second illuminator (121) that illuminates a substrate (G) that is adsorbed to and moved on the lower part of the stage (200), a second camera (122) that scans the substrate (G) from the lower part of the stage (200), and a second backlight (123) that outputs a backlight from the upper side of the stage (200).

[0040] Here, FIG. 3 illustrates a stage (200) that adsorbs a substrate (G) as an example, and additionally, a second optical system (120) may be installed on the substrate (G) and the stage (200) of FIG. 2.

[0041] The second illuminator (121) emits light in an upwardly inclined direction from the bottom of the stage (200). At this time, it is preferable that the second illuminator (121) be oriented at an angle of inclination of 12 to 16° relative to the center of the substrate (G). This is the optimal downward illumination angle for detecting microcracks formed around each side of the substrate (G).

[0042] To this end, the second illuminator (121) may be composed of a pair of lighting lamps spaced apart from each other. The pair of lighting lamps are spaced apart from each other and emit light directed toward the same point at an angle of inclination of 12 to 16°.

[0043] Such first and second illuminators can ensure superior visibility when converting the difference map of a scanned image. This is explained with reference to FIGS. 10 and FIGS. 11.

[0044] FIG. 10 is a drawing illustrating an example of a measurement image, and FIG. 11 is a drawing comparing visibility according to the directional angle of the illuminator, which are photographs taken of an example illuminated through the first illuminator (111) for example.

[0045] Figure 10 (a) is a side view of the edge portion of the substrate (G), and Figure 10 (b) is an enlarged view of the edge portion.

[0046] In addition, Figure 11 (a) and (b) were illuminated with different filters and angles, and it was confirmed that each included empty areas, edge areas, cracks, surface areas, and grinding areas.

[0047] Here, (a) of FIG. 11 is an image obtained by combining blue and cross lighting from the first illuminator (122) and illuminating at a directional angle of 26°, and (b) of FIG. 11 is an image obtained by illuminating with white light from the first illuminator (122) at a directional angle of 13°.

[0048] When comparing the two images, it is confirmed that in Fig. 11 (b), the crack is brightly shining but is scanned as a dot shape that does not extend horizontally from the edge, whereas in Fig. 11 (a), a shape that extends horizontally from the edge can be confirmed.

[0049] That is, it was confirmed that the visibility of the crack was superior when illuminating with a combination of blue and cross at a directional angle of 26˚ from the first illuminator (111).

[0050] That is, the light directional angle of the first illuminator (111) and / or the second illuminator (121) of the present invention has critical significance in that it can secure superior visibility when detecting defects of cracks in a scanned image.

[0051] The second backlight (123) outputs backlight from the upper side of the stage (200). The backlight provides illumination to check for the presence of microcracks around both sides of the substrate (G) through the stage (200), which has a narrow width compared to the substrate (G).

[0052] Here, the substrate (G) is supported (e.g., vacuum adsorption) on the lower part of the stage (200) and is moved in one direction or rotated by the stage (200).

[0053] Therefore, the second backlight (123) provides backlighting from the top of the stage (200).

[0054] The second camera (122) scans the substrate (G) that is transported and rotated while adsorbed to the lower part of the stage (200) and outputs an image to the control unit (300).

[0055] For example, the first camera (112) or the second camera (122) can check the scan area based on the position pattern (+) of the substrate (G) fixed to the stage (200) that moves in one direction, and tilt correction for adjusting the aiming angle and focus can be performed. It is preferable that such tilt correction of the camera be performed automatically by the control of the control unit.

[0056] In addition, the first camera first scans the edge portions on both sides of the four sides of the substrate moving in one direction, and after the stage (200) is rotated 90 degrees and moved in the reverse direction, it secondarily scans the other edge portions of the substrate whose orientation has been deformed and outputs them to the control unit.

[0057] The control unit (300) controls the stage (200) and the optical unit (100). Here, the control unit (300) can control the movement and rotation of the stage (200) and, in conjunction with this, controls the optical unit (100).

[0058] For example, when the control unit (300) places the substrate (G) on the stage (200), it rotates the stage (200) in one direction to move the substrate (G) to a fixed position where the first camera (112) and / or the second camera (122) (hereinafter, for convenience of explanation, the description is limited to the first camera (112)) is fixed. At this time, the control unit (300) checks the position pattern (+) through the scan image of the substrate (G) received from the first camera (112) and performs tilt correction on the first camera. Then, after tilt correction or if tilt correction is not required, the control unit drives the first camera to scan both edge portions of the substrate (see FIG. 4 (a)).

[0059] And when the first scan of the first camera (112) is completed, the control unit (300) rotates the stage (200) 90 degrees and then moves the stage (200) in the opposite direction.

[0060] Here, the first camera is fixed in a fixed state and can scan a substrate moving in the opposite direction by fixing it at the same directional angle as the first scan. At this time, since the substrate is rotated 90 degrees unlike in the first scan, the front and rear edges that were not scanned in the first scan form both sides.

[0061] Therefore, when the substrate (G) rotated 90 degrees after the first scan, the first camera (112) scans the two edge portions that were not scanned during the first scan.

[0062] Additionally, the control unit (300) converts a scanned image received from the optical unit (100), detects a plurality of candidate defect elements through the converted image, and then detects candidate defect elements corresponding to the set microcrack conditions through first and second filtering processes to finally detect the presence or absence of microcracks. To this end, the control unit (300) may be equipped with a Difference Map algorithm and a filtering algorithm.

[0063] A Difference Map is an image that represents defect elements in black and white based on the difference in thresholds between pixels.

[0064] For example, defect elements of the substrate (G) include scratches, cracks, chipping, breakouts, burrs, etc., as shown in FIG. 8. Among these, microcracks are difficult to distinguish because their shape is very similar to that of a scratch, as shown in the illustrated image.

[0065] Accordingly, the control unit (300) detects microcracks through first and second filtering based on the crack conditions set in the image converted by the Difference Map algorithm according to the set crack conditions, for example, line shape (form), horizontal direction in the scan direction (direction), edge of the substrate (G) (position), and same position in the upper image and lower image (sameness).

[0066] The alarm unit (500) outputs an alarm by the control unit (300).

[0067] The display (400) outputs the inspection process and results of the substrate (G) under the control of the control unit (300). For example, the display (400) can output at least one of an image of the substrate (G) scanned by the optical unit (100), crack information and crack detection results detected in the image, and an alarm message.

[0068] The present invention includes the above-described configuration, and a microcrack inspection method according to the present invention will be described below.

[0069] FIG. 4 is a flowchart illustrating a microcrack inspection method according to the present invention, and FIG. 5 is a diagram illustrating the process of FIG. 4.

[0070] Referring to FIGS. 4 and 5, the microcrack inspection method according to the present invention includes a step S100 of introducing a substrate (G), a step S200 of measuring a position pattern (+) and correcting the tilt, a step S300 of performing a first scan, a step S400 of rotating the substrate (G), a step S500 of performing a second scan, a step S600 of crack inspection and alarm, and a step S700 of discharging the substrate (G).

[0071] Step S100 is the step of introducing a substrate (G) into a stage (200). Here, the substrate (G) includes edge portions forming a total of four surfaces (A, B, C, D) as shown in FIG. 5 (a). At this time, the front of the introduced substrate (G) is surface B, the rear is surface D, and the two edge portions may be surfaces A and C. Additionally, a position pattern (+) is formed on both sides of surface B, which faces the front, that is, at the position corresponding to the front side on surfaces A and C. The stage (200) moves in one direction under the control of the control unit (300) and moves the substrate (G) to an area facing the first camera (112) and / or the second camera (122) (hereinafter collectively referred to as cameras).

[0072] Step S200 is a step in which the control unit (300) tilts the orientation angle and distance of the camera (112, 122) through the position pattern (Align Mark) of the substrate (G) moved by the stage (200). Here, the camera (112, 122) scans the substrate (G) moved by the stage (200). The control unit (300) checks the position pattern (+) included in the image scanned by the camera (112, 122) and adjusts the orientation angle and focus of the camera (112, 122).

[0073] That is, the camera (112, 122) is fixed in the direction in which the stage moves and scans both edges of the substrate simultaneously.

[0074] Step S300 is a step in which the control unit (300) controls the camera (112, 122) to perform a first scan. The camera (112, 122) is fixed on the movement path of the stage (200), and the substrate (G) is moved in one direction by the stage (200). Accordingly, the camera (112, 122) simultaneously scans surface A and surface C among the four surfaces forming the edge of the substrate (G) according to the movement direction of the stage (200), and sequentially scans the areas of surface A and surface C according to the movement speed of the stage (200) and outputs them to the control unit (300). At this time, the scanning direction may be opposite to the movement direction of the stage (200).

[0075] Step S400 is a step in which the control unit (300) drives the stage (200) to rotate the substrate (G). Here, the control unit (300) detects the position of the substrate (G) in real time through the image of the camera or a sensor, and when the substrate (G) passes through the camera's scan area, stops the stage (200) and then rotates the stage (200) 90 degrees. At this time, the optical unit (100) is moved backward by the control of the control unit (300).

[0076] Here, as the stage is rotated 90 degrees, the substrate (G) has sides B and D that face forward and backward respectively in the first scan, as shown in (b) of FIG. 5, forming the edge portions on both sides.

[0077] Step S500 is a step of performing a second scan of the substrate (G) whose orientation has been deformed by the control of the control unit (300). Here, the control unit (300) controls the stage (200) to move in the opposite direction to the movement direction during the first scan and controls the camera (112, 122) to perform a second scan. Accordingly, the camera (112, 122) scans the B-side and D-side, which form the two edge portions of the substrate (G) moving along the stage (200), and outputs them to the control unit (300).

[0078] Step S600 is a step in which the control unit (300) analyzes a scanned image received from the camera (112, 122) to check for cracks, and if a crack is detected, controls the alarm unit (500) to output an alarm. Here, the alarm may be at least one of an alarm message through the display (400), an alarm sound and a light signal, an alarm sound through a speaker, and a light signal through a lamp. This is explained with reference to FIGS. 6 to 9.

[0079] FIG. 6 is a flowchart illustrating step S600, FIG. 7 is a diagram illustrating the image conversion process of FIG. 6, and FIG. 8 and FIG. 9 are diagrams illustrating candidate defect elements of a substrate.

[0080] Referring to FIGS. 6 to 9, step S600 includes step S610 for receiving a scanned image, step S620 for converting the image, step S630 for detecting a crack combination candidate group, step S640 for first filtering, step S640 for second filtering, step S660 for determining whether there is a crack, step S670 for outputting an alarm when a crack is detected, and step S680 for discharging the substrate (G).

[0081] Step S610 is a step in which the control unit (300) receives, respectively from the optical unit (100), a scanned image of the upper surface of the substrate (G) and a scanned image of the lower surface of the substrate (G).

[0082] Step S620 is a step in which the control unit (300) converts the received image. The control unit (300) converts the upper surface scan image and the lower surface scan image of the substrate (G) received from the camera into a Difference Map.

[0083] A Difference Map is a map based on the difference in horizontal / vertical thresholds between adjacent pixels, and can represent defect elements in black and white. An example of this is shown in FIGS. 5 and FIGS. 7.

[0084] Step S630 is a step in which the control unit (300) detects a plurality of candidate defect elements. The control unit (300) converts a scanned image into a difference map and then detects defect elements having different shading within the converted image (for example, elements expressed in a shading different from the background, such as line and dot shapes).

[0085] For example, as shown in FIG. 8, there is a possibility of various defects (Scratch, Chipping, Broken, Burr, Particle, Crack) existing on the substrate (G). Among these defect elements, cracks and scratches have a line-like shape as shown in FIG. 8, so they are difficult to distinguish within the transformed image. Therefore, the present invention detects a group of candidate defect elements in order to accurately detect cracks.

[0086] Step S640 is a step in which the control unit (300) first filters the detected candidate defect elements. Here, the control unit (300) sets conditions for cracks. Referring to FIG. 9, the set crack conditions may be at least one of location (e.g., adjacent to each edge of the substrate (G)), shape (e.g., line type, dot type), direction (e.g., horizontal or vertical direction relative to the scan direction), and identity (e.g., being in the same position on the upper and lower surfaces of the substrate (G)).

[0087] That is, the control unit (300) performs a first filtering process according to the set conditions, leaving the defective element corresponding to at least one of the above conditions (e.g., a defective element having a line-shaped form) and removing all remaining elements.

[0088] Step S650 is a step in which the control unit (300) performs a second filtering of the first filtered defect element candidate group. Here, the control unit (300) checks the directionality of the line-shaped defect elements remaining in the converted image after the first filtering.

[0089] For example, the control unit (300) detects a defect element that has directionality in a direction that intersects the scan direction (e.g., front-back direction) and the horizontal direction among the first filtered line-type defect elements.

[0090] Step S660 is a step in which the control unit (300) detects whether there is a crack through the result of the second filtering. For example, if there is a remaining element among the initial defect candidate group detected after the second filtering (for example, a line-shaped defect element extended in the horizontal direction when the scan direction is the front-back direction), the control unit (300) determines it as a crack and controls the output of an alarm through Step S670.

[0091] More preferably, the control unit (300) outputs to the display (400) in the case where a defect element among the conditions set above satisfies the directionality but does not correspond to the identity requirement, so that an administrator can manually determine whether there is a defect.

[0092] Step S680 is a step of ejecting the substrate (G). The control unit (300) outputs the inspection result to the display (400) and ejects the substrate (G) from the stage (200).

[0094] Therefore, the present invention was able to detect microcracks through first and second-stage filtering based on microcrack conditions set in an image converted into a Difference Map method that displays defect elements as black and white based on the difference in horizontal / vertical thresholds between adjacent pixels. Such sequential filtering makes it easier to distinguish defects of similar shapes, such as cracks and scratches.

[0096] As described above, the present invention has been explained with reference to the illustrated drawings; however, the present invention is not limited by the embodiments and drawings described above, and various implementations are possible within the scope of the claims by those skilled in the art. Explanation of the symbols

[0098] 100 : Optical unit 110 : First optical system 111: First illuminator 112: First camera 113 : First backlight 120 : Second optical system 121 : Second illuminator 122 : Second camera 123 : 2nd Backlight 200 : Stage 300 : Control unit 400 : Display 500 : Alarm unit G, Glass : Substrate

Claims

Claim 1 A microcrack inspection device comprising: a stage (200) for transporting and rotating a substrate (G); an optical unit (100) for scanning a substrate (G) supported by the stage (200); and a control unit (300) for converting an image of the substrate (G) scanned by the optical unit (100) into a Difference Map to extract a plurality of candidate defect elements, and sequentially removing elements that do not meet the set microcrack conditions from the plurality of candidate defect elements extracted through a plurality of filtering processes to inspect for the presence or absence of microcracks; wherein the control unit (300) calculates a plurality of candidate defect elements, performs a first filtering to detect a defect element including at least one of the location of the defect element, the scan direction, the shape, and whether the defect elements formed on the upper and lower surfaces are in the same location, and performs a second filtering to calculate a defect element having directionality in a direction intersecting the scan direction among the defect elements detected by the first filtering. Claim 2 delete Claim 3 In claim 1, the optical unit (100) comprises at least one of a first optical system (110) that scans the upper surface of a substrate (G) and a second optical system (120) that scans the lower surface of a substrate (G); the first optical system (110) comprises a first camera (112) that scans the upper surface of a substrate (G) from the upper side of a stage (200), a first illuminator (111) that illuminates the substrate (G) from the upper side of a stage (200), and a first backlight (113) that provides backlight to the substrate (G) from the lower side of a stage (200); and the second optical system (120) comprises a second illuminator (121) that illuminates the substrate (G) from the lower side of a stage, a second camera (122) that scans the substrate (G) from the lower side of a stage (200), and a backlight that provides backlight to the substrate (G) from the upper side of a stage (200). Microcrack inspection device including a second backlight (123). Claim 4 A microcrack inspection device according to claim 3, wherein the first illuminator (111) illuminates the substrate (G) in a direction inclined at 25 to 30° with respect to the center of the substrate (G). Claim 5 A microcrack inspection device according to claim 3, wherein the second illuminator (121) illuminates the substrate (G) in a direction inclined at 12 to 16° with respect to the center of the substrate (G). Claim 6 delete Claim 7 a) a step of moving a substrate (G) supported on a stage (200) in one direction by the control of a control unit (300) so that a first camera scans the upper surface of the substrate (G) and a second camera scans the lower surface of the substrate (G); and b) a step of analyzing the scanned image to detect microcracks and outputting an alarm; wherein step b) comprises b-1) a step in which the control unit (300) receives a scanned image received from a camera and converts it into a Difference Map; b-2) a step of detecting a plurality of candidate defect elements in the image converted into a Difference Map; b-3) a first filtering step of performing first filtering on the candidate defect elements to detect at least one defect element among the location of the defect element, the scan direction, the shape, and whether the defect elements formed on the upper and lower surfaces are in the same location; b-4) a second filtering step of extracting a defect element having directionality in a direction intersecting the scan direction among the defect elements detected by the first filtering; and b-5) a step of outputting an alarm when a defect element having a set directionality is detected after secondary filtering; a microcrack inspection method comprising. Claim 8 delete Claim 9 A microcrack inspection method according to claim 7, wherein a) step comprises: a-1) a step of introducing a substrate (G) into a stage (200); a-2) a step of measuring a position pattern marked on the substrate (G) to tilt correct the orientation angle or position of the camera; a-3) a step of moving the stage (200) to move the substrate (G) to a position where the fixed camera is oriented, and a step of first scanning the two edge portions of the substrate (G) with the camera; a-5) a step of rotating the stage (200) by 90°; and a-6) a step of moving the stage (200) in the reverse direction to move the substrate (G) to a position where the fixed camera is oriented, and a step of secondarily scanning the two edge portions of the substrate (G) that were not captured during the first scan with the camera.

Images