Defect inspection equipment

Abstract

The present invention relates to a defect inspection device. Specifically, the defect inspection device according to one embodiment of the present invention includes: an image acquisition unit, which acquires an image of a target loaded on a table; a control unit, which controls the movement of the table and controls the operation of the image acquisition unit; a correction unit, which corrects a second image acquired by the image acquisition unit when the table moves along a second direction based on a first image acquired by the image acquisition unit when the table moves along a first direction; and a defect judgment unit, which compares the corrected second image with a pre-stored reference image to judge whether the target has a defect.

Description

Technical Field

[0001] The present invention relates to a defect inspection device and a defect inspection method thereof. Background Art

[0002] Automatic optical inspection (AOI) devices are suitable for inspecting various inspection targets such as solder balls of semiconductor packages, printed circuit boards, or display panels. Such AOI devices inspect targets for fragmentation, size, hole or via size, conductor pitch, wiring width and length, artwork, paste, component position, soldering defects, and singular points.

[0003] Generally, the AOI moves a table in one direction to continuously photograph a target to be inspected, continuously obtains images of the target, and inspects whether the target has defects using an overlapped image obtained by overlapping the images.

[0004] However, among the objects (e.g., wiring) included in the overlapped image, wiring mounted in a direction consistent with the moving direction of the table is obvious due to continuous overlap, but wiring mounted in a direction different from the moving direction of the table is unclear because it does not overlap. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a defect inspection device and a defect inspection method thereof: when inspecting defects of a target on which wiring and semiconductor elements are mounted, images of wiring and semiconductor elements are made clearer regardless of the mounting direction.

[0006] Furthermore, another technical problem to be solved by the present invention is to provide a defect inspection device and a defect inspection method thereof: regardless of the direction of mounting wiring and semiconductor elements, the images of wiring and semiconductor elements, etc. are made clear, so that it is possible to more accurately judge whether the target has defects or not.

[0007] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art through the following description.

[0008] In order to solve the above technical problems, on the one hand, a defect inspection device according to an embodiment of the present invention may include: an image acquisition unit, irradiating light toward a target loaded on a stage, and acquiring an image from the light reflected by the target; a control unit, controlling the movement of the stage so that the stage moves along a first direction and a second direction perpendicular to the first direction, and controlling the operation of the image acquisition unit; a correction unit, correcting a second image acquired by the image acquisition unit when the stage moves along the second direction based on the first image acquired by the image acquisition unit when the stage moves along the first direction; and a defect judgment unit, comparing the corrected second image with a pre-stored reference image to judge whether the target has a defect.

[0009] Here, the control unit may control the movement of the tabletop to move in a first direction during a first operation period, and may control the movement of the tabletop to move in a second direction during a second operation period different from the first operation period.

[0010] Here, the control portion may perform control to move the table in the second direction during the second operation period after the first operation period has elapsed.

[0011] Here, the first operation time period may be from after the target is placed on the table to before the correction unit processes the first image.

[0012] Here, the correction unit calculates a first grayscale value included in the first image, generates a first matrix using the first grayscale value, calculates a first eigenvalue of the first matrix, and corrects the second image using the first eigenvalue.

[0013] Here, the correction unit may calculate a second grayscale value included in the second image, may generate a second matrix using the second grayscale value, may calculate a second eigenvalue of the second matrix, and may correct the second image based on the first eigenvalue and the second eigenvalue.

[0014] Here, the correction unit may calculate an average eigenvalue of the first eigenvalue and the second eigenvalue, and may apply the average eigenvalue to the second image to perform the correction.

[0015] Here, the image acquisition unit may include: a light irradiation unit that irradiates light toward the target; at least one shooting unit that captures light reflected from the target according to a preset shooting area unit and shoots an image of the shooting area; and an image data generation unit that generates image data corresponding to the image.

[0016] Here, when the table moves in the first direction, the imaging unit may capture the first image of the imaging region that changes with the movement of the table.

[0017] Here, the first image may be an image first acquired when the object is loaded on the table and the table moves along the first direction.

[0018] Here, when the table moves in the second direction, the imaging unit may continuously capture the second image of the imaging region that changes with the movement of the table.

[0019] Here, the correction unit may correct each of the second images acquired continuously based on the first image.

[0020] Here, the image acquisition unit may include: a first imaging unit for imaging a first area of ​​the table surface in imaging area units; and a second imaging unit for imaging a second area of ​​the table surface in imaging area units.

[0021] On the other hand, a defect inspection method according to an embodiment of the present invention may include: a loading judgment step of judging whether a target is loaded on a table; a first direction movement control step of controlling the movement of the table top so that the table top moves along a first direction when the target is loaded; a first image acquisition step of irradiating light toward the target and acquiring a first image from light reflected from the target when the table top moves along the first direction; a second direction movement control step of controlling the movement of the table top so that the table top moves along a second direction perpendicular to the first direction when the first image is acquired; a second image acquisition step of irradiating light toward the target and acquiring a second image from light reflected from the target when the table top moves along the second direction; an image correction step of correcting the second image based on the first image; and a defect judgment step of comparing the corrected second image with a pre-stored reference image to judge whether there is a defect.

[0022] Here, in the image correction step, the first grayscale value included in the first image can be calculated, the first matrix can be generated using the first grayscale value, the first eigenvalue (Eigen value) of the first matrix can be calculated, and the second image can be corrected using the first eigenvalue.

[0023] Here, in the image correction step, the second grayscale value included in the second image can be calculated, the second matrix can be generated using the second grayscale value, the second eigenvalue of the second matrix can be calculated, and the second image can be corrected based on the first eigenvalue and the second eigenvalue.

[0024] Here, in the image correction step, an average eigenvalue of the first eigenvalue and the second eigenvalue may be calculated, and the average eigenvalue may be applied to the second image for correction.

[0025] Specific details of other embodiments are included in the detailed description and drawings.

[0026] As described above, an embodiment of the present invention can provide a defect inspection device and a defect inspection method thereof that can make images of wiring and semiconductor elements clearer regardless of the mounting direction when inspecting defects of an object mounted with wiring and semiconductor elements.

[0027] Furthermore, an embodiment of the present invention can provide a defect inspection device and a defect inspection method thereof: regardless of the direction of mounting wiring and semiconductor elements, etc., the image of wiring and semiconductor elements, etc. can be made clear, so that whether the target is defective or not can be judged more accurately.

[0028] The effects according to the embodiments are not limited to the above-described examples, and more various effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a block diagram schematically showing a defect inspection system according to an embodiment of the present invention.

[0030] Figure 2 is a block diagram schematically showing a defect inspection apparatus according to an embodiment of the present invention.

[0031] Figure 3 FIG. 1 is a diagram schematically showing a target mounted on a table and a head including an image acquisition unit according to an embodiment of the present invention.

[0032] Figure 4 is along Figure 3 Cross-sectional view of section Ⅰ-Ⅰ'.

[0033] Figure 5 is along Figure 3 Cross-sectional view of II-II'.

[0034] Figure 6 as well as Figure 7 FIG. 1 is a diagram schematically showing an imaging area set according to an embodiment of the present invention.

[0035] Figure 8 FIG. 1 is a diagram showing an embodiment in which a table moves along a first direction according to an embodiment of the present invention.

[0036] Fig. 9 It is schematically shown that Figure 8 FIG. 4 is a diagram of an embodiment in which a table shown in FIG. 4 moves along a first direction to acquire a first image of a photographing area.

[0037] Fig.10 It is schematically shown that the Figure 8 A graph of the first grayscale values ​​of the first image.

[0038] Fig.11is a flowchart for illustrating an embodiment of calculating a first eigenvalue according to an embodiment of the present invention.

[0039] Fig.12 FIG. 1 is a diagram illustrating an embodiment in which a table moves along a second direction according to an embodiment of the present invention.

[0040] Fig.13 It shows that with Fig.12 The table is shown in a diagram of an embodiment in which the table moves along a second direction to acquire a second image of the photographing area.

[0041] Fig.14 It is schematically shown that the Fig.12 A graph of second grayscale values ​​of a second image.

[0042] Fig.15 FIG. 1 is a flowchart for explaining an embodiment of correcting the second image according to an embodiment of the present invention.

[0043] Fig.16 : is a diagram schematically showing the third grayscale value included in the corrected image.

[0044] Fig.17 is a flowchart for illustrating a defect inspection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] If you refer to the attached Figure 1 The advantages, features and methods of implementing the present invention will become clear from the embodiments described in detail below. However, the present invention is not limited to the embodiments disclosed below, and can be implemented in various forms that are different from each other. The embodiments of the present invention are only provided to make the disclosure of the present invention complete and to fully inform the scope of the present invention to those with ordinary knowledge in the technical field to which the present invention belongs. The present invention is limited only by the scope of the claims.

[0046] When it is described that an element or layer is "on" another element or layer, it not only includes the case where it is located immediately above the other element or layer, but also includes the case where other layers or other elements are interposed therebetween. Throughout the specification, the same reference numerals describe the same constituent elements.

[0047] Although the terms first, second, etc. are used to describe various components, these components are obviously not limited by these terms. The above terms are only used to distinguish one component from another component. Therefore, it is obvious that within the technical concept of the present invention, the first component mentioned below can also be the second component. As long as the different meanings are not clearly expressed in the context, the singular expression includes the plural expression.

[0048] The following embodiments may be applicable to various display devices such as an organic light emitting display device, a liquid crystal display device, an electric field emission display device, and an electrophoretic display device.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or similar reference numerals are used for the same components in the drawings.

[0050] Figure 1 is a block diagram schematically showing a defect inspection system 10 according to an embodiment of the present invention.

[0051] Reference Figure 1 , the defect inspection system 10 may refer to a system for inspecting whether a target (Object, not shown) has defects. Specifically, the defect inspection system 10 may refer to a system for inspecting whether components, wiring, etc. mounted on the target have defects, thereby distinguishing good targets from bad targets. Here, for example, the target may be a display panel that displays an image, a substrate on which semiconductor components (such as thin film transistors (TFT: Thin Film Transistor), wiring, organic light-emitting layer, etc.) are arranged, or a printed circuit substrate (PCB: Printed Circuit Board) including a driver IC and wiring, etc. However, it is not limited to this. For convenience, unless otherwise stated, the target described below is a display panel. In addition, defects may include stains or dust on the target in addition to process defects or component defects.

[0052] Such a defect inspection system 10 may include a loading device 100 , a defect inspection device 200 , a buffer device 300 , an unloading device 400 , and the like.

[0053] The loading device 100 can load the target to be inspected from a cassette (not shown) storing a plurality of targets and provide the target to the defect inspection device 200 .

[0054] The defect inspection device 200 may perform a defect inspection process for the target provided from the loading device 100. Specifically, the defect inspection device 200 may determine whether there is a defect for the loaded target according to the defect determination method, and may output a defect inspection result for the loaded target. Here, for example, in the defect inspection process, an image for the target is compared with a reference image for the target as a good product, and the defect of the target is inspected by whether the image and the reference image are similar within a predetermined error range. However, it is not limited thereto.

[0055] The buffer device 300 may be disposed between the defect inspection device 200 and the unloading device 400 , and may temporarily accommodate objects that have completed defect inspection.

[0056] The unloading device 400 can classify the objects that have completed defect inspection according to the defect inspection results output by the defect inspection device 200, and unload them to subsequent process devices or inspection devices.

[0057] The above-mentioned components or parts of the defect inspection device 200 are exemplary, and the present invention is not limited thereto. In addition, the defect inspection device 200 may further include a robot arm and a conveyor belt for transferring objects between the components.

[0058] Hereinafter, the defect inspection apparatus 200 according to an embodiment of the present invention will be described in detail.

[0059] Figure 2 is a block diagram schematically showing a defect inspection apparatus 200 according to an embodiment of the present invention.

[0060] Reference Figure 2 According to an embodiment of the present invention, a defect inspection device 200 may include a control unit 210, an image acquisition unit 220, a table 230, a correction unit 240, a defect judgment unit 250, a storage unit 260, an output unit 270, and the like.

[0061] The control section 210 may control the movement of a stage 230. Specifically, the control section 210 may output a first control signal to the stage 230 to command the stage 230 to move in a specific direction (eg, up, down, left, right, etc.).

[0062] Here, the control unit 210 may first perform control to move the table 230 in a direction different from the one direction before performing defect inspection of the target while the table 230 moves in the one direction, and then perform control to move the table 230 in the one direction for defect inspection of the target. Figures 8 to 15 To be described later.

[0063] In addition, the control unit 210 may control the operation of the image acquisition unit 220. As described later, the operation of the image acquisition unit 220 may mean acquiring an image of a target loaded on the table 230. For example, if the target is loaded on the table 230, the control unit 210 may output a second control signal to the image acquisition unit 220 to instruct the image acquisition unit 220 to execute the operation of acquiring an image of the target.

[0064] Such a control unit 210 may be hardware (such as an electronic control unit (ECU: Electronic Controller Unit), a micro control unit (MCU: Micro Controller Unit), etc.) or software running on these hardware or a combination of these.

[0065] The image acquisition unit 220 may receive the second control signal from the control unit 210 to irradiate light to the target mounted on the table 230 , and may acquire an image from the light reflected from the target. Such an image acquisition unit 220 may be included in the head 30 .

[0066] Such an image acquisition unit 220 may include a light irradiation unit 221 , a photographing unit 222 , and an image data generation unit 223 .

[0067] The light irradiation unit 221 can irradiate light toward the target. Specifically, the light irradiation unit 221 can be provided on the upper portion of the table 230 on which the target is loaded to irradiate light toward the target. As one embodiment, the light irradiation unit 221 can be implemented as a plurality of backlights that irradiate broadband light (Broadband light) from ultraviolet rays to near infrared rays. As another embodiment, it can be implemented as an argon ion laser, a helium series laser, etc.

[0068] The photographing unit 222 can capture light reflected from the target and take an image of the photographing area. Such a photographing unit 222 can capture light according to a preset photographing area unit and take an image of the photographing area. The number of the photographing units 222 can be at least one, and each of the plurality of photographing units 222 can photograph a certain area of ​​the table 230 corresponding to the position where each photographing unit 222 is set as a photographing area unit. At this time, each of the plurality of photographing units 222 can photograph a certain area of ​​the table 230 and take an image of a part of the target loaded on the table 230.

[0069] The photographing unit 222 can be implemented as a charge-coupled device (CCD) camera of the time delay integration (TDI) method, and the CCD camera of the TDI method can be implemented using multiple pixels. When the CCD camera photographs, each of the multiple pixels can output a gray value (Gray value, or gray level). The image can be a combination of these gray values. In addition, the image can include information about the pattern formed on the target (for example, wiring, semiconductor elements, etc. mounted on the target). In addition, the above-mentioned photographing area can be determined by the performance of the CCD camera of the TDI method.

[0070] The image data generating unit 223 may generate image data corresponding to the image captured by the capturing unit 222. Here, the image data may have grayscale values ​​corresponding to a plurality of pixels. The image data generating unit 223 may be implemented as an analog-digital converter (ADC).

[0071] exist Figure 2 In the figure, the light irradiation unit 221, the photographing unit 222 and the image data generating unit 223 are illustrated as separate structures, but are not limited to this. According to an embodiment, at least two of the light irradiation unit 221, the photographing unit 222 and the image data generating unit 223 may be combined.

[0072] The table 230 can support a target (e.g., a display panel). The table 230 can be in the form of a plate such as a quadrilateral or a circle, but is not limited thereto. Here, when the target is a display panel (not shown), the table 230 can be connected to a driving unit (not shown) of the display panel and can transmit a control signal to the display panel.

[0073] In addition, the table 230 can move up, down, left, and right, and can also rotate by the first control signal of the control unit 210. For example, the table 230 can receive the first control signal of the control unit 210 to move in a first direction, and can move in a second direction perpendicular to the first direction.

[0074] Here, the first direction and the second direction may represent directions perpendicular to each other on a two-dimensional plane. For example, on a two-dimensional plane formed by an x-axis and a y-axis, the first direction may be the x-axis direction, and the second direction may be the y-axis direction. However, this is not limited thereto.

[0075] In addition, when the table 230 moves along the first direction, the operation of determining whether the target has a defect is not performed, and when the table 230 starts to move along the second direction perpendicular to the first direction, the operation of determining whether the target has a defect can be started. That is, before determining whether the target has a defect, in order to obtain data for image correction, the table 230 can move along the first direction, and in order to perform the operation of determining whether the target has a defect, the table 230 can move along the second direction perpendicular to the first direction.

[0076] The correction unit 240 can process the image data output from the image data generation unit 223. As an embodiment, the correction unit 240 can obtain the brightness characteristic value of each pixel corresponding to each gray value by using the difference between each gray value constituting the image data and the gray value of the surrounding. Such a correction unit 240 can be implemented as an image processor (Image processor) that pre-processes the image data.

[0077] The correction unit 240 may correct the second image acquired by the image acquisition unit 220 when the table 230 moves in the second direction based on the first image acquired by the image acquisition unit 220 when the table 230 moves in the first direction. As an example, the correction unit 240 may correct the second image using the grayscale value of each of the plurality of pixels constituting the first image.

[0078] The defect judgment unit 250 may compare the second image corrected by the correction unit 240 with the reference image pre-stored in the storage unit 260 to judge whether the target has defects. Specifically, the defect judgment unit 250 may receive data for the corrected second image from the correction unit 240, extract data for the reference image and the reference similarity from the storage unit 260, and calculate the similarity between the corrected second image and the reference image. At this time, if the similarity is less than the reference similarity, the defect judgment unit 250 may judge the target to be inspected as a target with defects. However, the present invention is not limited thereto.

[0079] The storage unit 260 may store data for each of a reference image and a reference similarity as a reference for determining whether a defect exists. The data stored in the storage unit 260 may be managed by the control unit 210 or the defect determination unit 250 .

[0080] The output unit 270 may receive data on defect inspection results for the target from the defect determination unit 250 and display the defect inspection results and the inspection status in real time.

[0081] Hereinafter, embodiments of the positional relationship between the head including the image acquisition unit 220 and the target mounted on the table 230 , and the light irradiated to the target by the image acquisition unit 220 will be described in detail.

[0082] Figure 3 2 is a diagram schematically showing a target 20 mounted on a table 230 and a head 30 including an image acquisition unit 220 according to an embodiment of the present invention. Figure 4 is along Figure 3 The cross-sectional view of Ⅰ-Ⅰ', Figure 5 is along Figure 3 Cross-sectional view of II-II'.

[0083] Reference Figure 3 According to an embodiment of the present invention, the table 230 can support the target 20 at the upper part, and the target 20 placed on the table 230 can be fixed to the upper part of the table 230. In addition, the table 230 can move along the first direction DR1, the second direction DR2, or the third direction DR3 together with the target 20. For example, the table 230 can move along the first direction DR1 together with the target 20. As another example, the table 230 can move along the second direction DR2 perpendicular to the first direction DR1 together with the target 20. Here, the movement of the table 230 can mean a one-way movement from one position to another position, or a round-trip movement from one position to another position and back to the original position.

[0084] Reference Figure 3 as well as Figure 4According to an embodiment of the present invention, the head 30 may be arranged on the upper part of the target 20 and fixed. The head 30 may include an image acquisition unit 220. For example, the light irradiation unit 221 and the shooting unit 222 included in the image acquisition unit 220 may be attached to the lower part of the head 30.

[0085] As the table 230 moves, the image acquisition unit 220 included in the head 30 can acquire an image of the target 20 placed on the table 230. As a specific example, the light irradiation unit 221 included in the head 30 can irradiate the first light L1 to the target 20 that moves along with the table 230 moving along the second direction DR2, and the shooting unit 222 included in the head 30 can capture the second light L2 reflected from the moving target 20 and shoot an image of the target 20.

[0086] In addition, when there are multiple imaging units 222, each of the multiple imaging units 222 can image an area corresponding to the position of each imaging unit 222 arranged at the lower part of the head 30 in an area corresponding to a portion of the table 230.

[0087] For example, when the number of the photographing units 222 is two, the first photographing unit 222a included in the image acquisition unit 220 can photograph the first area A of the table 230 as a photographing area unit, and the second photographing unit 222b included in the image acquisition unit 220 can photograph the second area B of the table 230 as a photographing area unit.

[0088] Reference Figure 3 as well as Figure 5 As another example, when the number of the photographing units 222 is three, the first photographing unit 222a can capture the second light L2 reflected from a portion of the target 20 corresponding to the first area A of the table 230 and take an image of a portion of the target 20, the second photographing unit 222b can capture the second light L2 reflected from another portion of the target 20 corresponding to the second area B of the table 230 and take an image of another portion of the target 20, and the third photographing unit 222c can capture the second light L2 reflected from another portion of the target 20 corresponding to the third area C of the table 230 and take an image of another portion of the target 20.

[0089] exist Figure 3 as well as Figure 5 The figure shows that the number of the imaging units 222 and the number of the regions A, B, and C of the table 230 are three. However, this is only used to help understand the embodiments of the present invention and is not limited to Figure 3 as well as Figure 5 The shapes and sizes of the regions A, B, and C may be preset in a manner corresponding to the target 20 to be inspected.

[0090] In addition, as described above, the photographing unit 222 can perform photographing according to a preset photographing area unit. The following describes an embodiment of the photographing area, and for the sake of convenience, the description is based on the number of the photographing units 222 being three.

[0091] In this specification, for the convenience of description, the horizontal and left-right directions of the table top 230 are defined as the first direction DR1, the longitudinal and front-back directions of the table top 230 are defined as the second direction DR2 perpendicular to the first direction DR1, and the height direction of the table top 230 is defined as the third direction DR3 perpendicular to both the first direction DR1 and the second direction DR2. However, the embodiment is not limited to the mentioned directions, and it should be understood that the first direction DR1, the second direction DR2, and the third direction DR3 represent relative directions that intersect each other.

[0092] Figure 6 as well as Figure 7 FIG. 1 is a diagram schematically showing an imaging area set according to an embodiment of the present invention.

[0093] Reference Figure 6 According to an embodiment, the first shooting areas 21a, 21b, 21c may be areas having a size corresponding to the size of each of the first to third areas A to C of the mesas 230 (e.g., the length of each of the first to third areas A to C extending along the first direction DR1, i.e., the width).

[0094] In this case, the first imaging unit 222a having the first imaging region 21a set therein can capture an image of a portion of the object 20 included in the first imaging region 21a in the first region A of the table 230 through a single imaging operation.

[0095] Also, the second imaging unit 222 b having the first imaging region 21 b set therein may capture an image of another portion of the object 20 included in the first imaging region 21 b in the second region B of the table 230 through one imaging operation.

[0096] Furthermore, the third imaging unit 222 c set with the first imaging region 21 c may capture an image of another portion of the object 20 included in the first imaging region 21 c in the third region C of the table 230 through one imaging operation.

[0097] Here, each of the first to third photographing units 222 a to 222 c may simultaneously photograph an image of a portion of the object 20 .

[0098] according to Figure 6The first imaging regions 21a, 21b, and 21c shown have the effect of reducing the inspection tact of the defect inspection process.

[0099] In addition, refer to Figure 7 , the second shot regions 22a, 22b, 22c may be regions having a size smaller than that of each of the first to third regions A to C of the mesa 230. Also, the size of each of the second shot regions 22a, 22b, 22c may be smaller than that of each of the first shot regions 21a, 21b, 21c. For example, the length (i.e., width) of each of the second shot regions 22a, 22b, 22c extending along the first direction DR1 and the length (i.e., diameter) of each of the second shot regions 22a, 22b, 22c extending along the second direction DR2 may be smaller than the width and diameter of each of the first shot regions 21a, 21b, 21c.

[0100] The number of the second shooting areas 22a, 22b, and 22c corresponding to each of the first to third areas A to C of the table 230 may be plural. For example, the number of each of the second shooting area 22a corresponding to the first area A of the table 230, the second shooting area 22b corresponding to the second area B of the table 230, and the second shooting area 22c corresponding to the third area C of the table 230 may be plural.

[0101] according to Figure 7 The second imaging regions 22 a , 22 b , and 22 c shown have the effect of being able to more accurately inspect defects of the target 20 .

[0102] in addition, Figure 6 The first shooting areas 21a, 21b, 21c and Figure 7 The number of each of the second photographing areas 22 a , 22 b , and 22 c shown is an example to help understand the embodiment, and is not limited thereto.

[0103] The following specifically describes a method of acquiring an image according to the moving direction of the table 230 and calculating the value required to correct the image. For convenience, the description is based on the case where the number of imaging units 222 is 3 and the imaging areas are the first imaging areas 21a, 21b, and 21c.

[0104] Figure 8 2 is a diagram showing an embodiment in which the mesa 230 moves along the first direction DR1 according to an embodiment of the present invention. Fig. 9 It shows that with Figure 8 The table 230 shown in the figure moves along the first direction DR1 to obtain the first image 23 of the shooting area. Fig.10It is schematically shown that the Fig. 9 A graph of first grayscale values ​​of the first image 23 .

[0105] Reference Figure 2 as well as Figure 8 According to an embodiment of the present invention, the control unit 210 may control the movement of the stage 230 to move the stage 230 in the first direction DR1 during the first operation period. That is, the control unit 210 may perform control to move the stage 230 in the first direction DR1 before starting defect inspection of the target 20 loaded on the stage 230.

[0106] Here, the first operation time period may mean a time period from when the target 20 is loaded on the table 230 and before the defect inspection for the target 20 is started. For example, the first operation time period may be from when the target 20 is loaded on the table 230 to when the correction unit 240 processes the first image 23. However, the end time point of the first operation time period is not limited to before the correction unit 240 processes the first image 23, but the end time point of the first operation time period may be arbitrarily designed and changed by the designer so that the first operation time period satisfies the situation that the target 20 is loaded and before the defect inspection for the target 20 is started.

[0107] As the table 230 moves along the first direction DR1 , the target 20 also moves along the first direction DR1 . In this case, the image acquisition unit 220 included in the head 30 may start scanning the target 20 , and the scanning direction may be a direction opposite to the first direction DR1 .

[0108] Reference Fig. 9 As an embodiment, the table 230 may move in a direction opposite to the first direction DR1 after moving a predetermined distance in the first direction DR1 to return to the initial position. Although not shown, as another embodiment, the table 230 may stop after moving a predetermined distance in the first direction DR1 from the initial position.

[0109] When the stage 230 moves in the first direction DR1 , each of the imaging units may capture the first image 23 for the imaging region that changes with (or moves together with) the movement of the stage 230 .

[0110] Reference Figure 5 as well as Fig. 9For example, the first photographing unit 222a can photograph a first image 23a of a portion of the target 20 corresponding to the first area A of the table 230, the second photographing unit 222b can photograph a first image 23b of another portion of the target 20 corresponding to the second area B of the table 230, and the third photographing unit 222c can photograph a first image 23c of another portion of the target 20 corresponding to the third area C of the table 230.

[0111] Here, the first image 23 may be the first image acquired when the target 20 is loaded on the table 230 and the table 230 moves along the first direction DR1. At this time, each of the first images 23a, 23b, 23c acquired during the movement of the table 230 along the first direction DR1 may be composed of a plurality of first grayscale values ​​24.

[0112] Reference Fig.10 , the correction unit 240 may calculate the first gray value 24 included in each of the first images 23a, 23b, and 23c. Furthermore, the correction unit 240 may generate a first matrix for each of the first images 23a, 23b, and 23c using the first gray value 24, and may calculate a first eigenvalue of the first matrix in order to correct the second image.

[0113] Reference Fig. 9 as well as Fig.10 For example, the correction unit 240 generates a first matrix and calculates a first eigenvalue of the first matrix using the first grayscale value 24 included in the first image 23a acquired from the first area A of the table 230. In addition, the correction unit 240 may calculate the first matrix and the first eigenvalue using the first grayscale value 24 included in the first image 23b acquired from the second area B of the table 230, and may calculate the first matrix and the first eigenvalue using the first grayscale value 24 included in the first image 23c acquired from the third area C of the table 230.

[0114] Here, the first matrix may be m×n (m and n are natural numbers) rows and columns composed of the first grayscale values ​​24, and may be expressed as follows [Formula 1].

[0115] [Mathematical formula 1]

[0116]

[0117] M 1 represents the first matrix, and x represents the first grayscale value.

[0118] In addition, an eigenvector represents a vector whose direction does not change after its linear transformation. Also, an eigenvector represents a vector that is not a 0 vector. Also, an eigenvalue represents a value corresponding to a multiple of a change in the length of the eigenvector.

[0119] At this time, the first eigenvalue can be calculated using the first matrix and can be calculated according to the following [Mathematical Formula 2].

[0120] [Mathematical formula 2]

[0121] M 1 ×υ=λ x ×υ

[0122] M 1 represents the first matrix, λ x represents the first eigenvalue, and υ represents a unit vector or an eigenvector (Eigenvector).

[0123] Fig.11 FIG. 4 is a flowchart for explaining an embodiment of calculating a first eigenvalue according to an embodiment of the present invention.

[0124] Reference Fig.11 , the defect inspection apparatus 200 according to an embodiment of the present invention determines whether the target 20 is loaded on the stage 230 ( S110 ).

[0125] When the target 20 has been loaded on the stage 230 ( S110 , Yes), the defect inspection apparatus 200 performs control to move the stage 230 in the first direction DR1 ( S120 ).

[0126] Thereafter, the defect inspection apparatus 200 performs imaging in units of imaging regions while the stage 230 moves in the first direction DR1, and acquires a first image 23 for the imaging region from the target 20 (S130).

[0127] If the first image 23 is acquired, the defect inspection device 200 calculates each first grayscale value 24 included in the first image 23 (S140), matrixes the first grayscale value 24 to generate a first matrix as shown in the above [Formula 1] (S150), and calculates the first eigenvalue of the first matrix according to the above [Formula 2] (S160) and stores it (S170).

[0128] The following specifically describes an embodiment of correcting the second image obtained during the defect inspection process of the target 20 using the above-mentioned first eigenvalue. For convenience, the description is based on the case where the number of imaging units 222 is 3 and the imaging areas are the first imaging areas 21a, 21b, and 21c.

[0129] Fig.12 2 is a diagram showing an embodiment in which the table 230 moves along the second direction DR2 according to an embodiment of the present invention. Fig.13 It shows that with Fig.12 The table 230 shown in the figure moves along the second direction DR2 to obtain the second image 25 for the shooting area. Fig.14 It is schematically shown that the Fig.12 A graph of second grayscale values ​​of the second image 25 .

[0130] Reference Fig.12 , the control unit 210 according to an embodiment of the present invention may control the movement of the table 230 to move the table 230 in the second direction DR2 during a second operation period different from the first operation period. That is, the control unit 210 may control the table 230 to move in the second direction DR2 perpendicular to the first direction DR1 in order to start defect inspection for the target 20.

[0131] Here, in the case where the first operation period is a period before starting defect inspection for the target 20 , the control part 210 may perform control to move the stage 230 in the second direction DR2 during a second operation period after the first operation period has elapsed.

[0132] As the table 230 moves along the second direction DR2, the target 20 also moves along the second direction DR2. In this case, the image acquisition unit 220 included in the head 30 may start scanning the target 20, and the scanning direction may be a direction opposite to the second direction DR2.

[0133] Reference Fig.13 When the table 230 moves along the second direction DR2, the imaging unit 222 may continuously capture second images 25a, 25b, and 25c of the imaging area that changes with (or moves together with) the movement of the table 230.

[0134] Reference Figure 5 as well as Fig.13 For example, the first imaging unit 222a may capture a second image 25a of a portion of the target 20 corresponding to the first region A of the table 230. In this case, the second images 25a_1 and 25a_2 acquired from the first region A of the table 230 may be continuously captured images.

[0135] For another example, the second imaging unit 222b may capture a second image 25b of another portion of the target 20 corresponding to the second region B of the table 230. In this case, the second images 25b_1 and 25b_2 acquired from the second region B of the table 230 may be continuously captured images.

[0136] For another example, the third imaging unit 222c may capture a second image 25c of another portion of the target 20 corresponding to the third region C of the table 230. In this case, the second images 25c_1 and 25c_2 acquired from the third region C of the table 230 may be continuously captured images.

[0137] Each of the second images 25a, 25b, and 25c continuously acquired during the movement of the table 230 along the second direction DR2 may be composed of a plurality of second grayscale values ​​26. At this time, if the second images 25a, 25b, and 25c are continuously acquired, the correction unit 240 may correct each of the continuously acquired second images 25a, 25b, and 25c based on each of the first images 23a, 23b, and 23c. For example, the correction unit 240 may generate a second matrix for each of the second images 25a, 25b, and 25c using the second grayscale value 26 included in each of the second images 25a, 25b, and 25c.

[0138] like Fig.14 As shown, Fig.13 Taking the second image 25a_2 of one of the second images 25a_1 and 25a_2 obtained from the first area A of the table 230 as a reference, the correction unit 240 can generate a second matrix using the second grayscale value 26 included in the second image 25a_2 obtained from the first area A of the table 230, and calculate the second eigenvalue of the second matrix.

[0139] Here, the second matrix may be m×n rows and columns consisting of the second grayscale values ​​26, and may be represented by the following [Formula 3].

[0140] [Mathematical formula 3]

[0141]

[0142] M 2 represents the second matrix, and y represents the second grayscale value.

[0143] In addition, the correction unit 240 can calculate the second matrix and the second eigenvalue using the second grayscale value 26 included in the second image 25b obtained from the second area B of the table 230, and can calculate the second matrix and the second eigenvalue using the second grayscale value 26 included in the second image 25c obtained from the third area C of the table 230.

[0144] Although not shown in the figure, the shooting area is Figure 7In the case of the second photographing area 22 shown, the embodiment of acquiring the first image when the table 230 moves a predetermined distance along the first direction DR1 and the embodiment of correcting the second image when the table 230 moves along the second direction DR2 can be repeatedly performed.

[0145] Hereinafter, a method of acquiring and correcting the second image 25 for determining whether or not the target 20 has a defect will be specifically described using a flowchart.

[0146] Fig.15 is a flowchart for explaining an embodiment of correcting the second image 25 according to an embodiment of the present invention. Fig.16 2 is a diagram schematically showing the third grayscale value 28 included in the corrected image 27 .

[0147] Reference Fig.15 The defect inspection apparatus 200 according to an embodiment of the present invention checks whether the first feature value calculated from the first image 23 is stored in the storage unit 260 (S210). This may mean determining whether to start defect inspection.

[0148] If the first characteristic value is stored (S210, yes), the defect inspection device 200 performs control to move the table 230 in a second direction DR2 perpendicular to the first direction DR1 (S220), obtains a second image 25 for the shooting area from the target 20 by shooting in units of the shooting area during the movement of the table 230 in the second direction DR2 (S230), and calculates each of the second grayscale values ​​26 included in the second image 25 (S240).

[0149] Subsequently, the defect inspection apparatus 200 matrixes the second grayscale value 26 to generate a second matrix ( S250 ), and calculates a second eigenvalue of the second matrix ( S260 ).

[0150] Here, the second matrix can be represented by the above-mentioned [Formula 3], the second eigenvalue can be calculated using the second matrix, and can be calculated according to the following [Formula 4].

[0151] [Formula 4]

[0152] M 2 ×υ=λ y ×υ

[0153] M 2 represents the second matrix, λ y represents the second eigenvalue, and υ represents a unit vector or an eigenvector (Eigenvector).

[0154] For example, the correction unit 240 converts the second grayscale value 26 into a second matrix according to the above-mentioned [Formula 3], and calculates the second eigenvalue of the second matrix according to the above-mentioned [Formula 4].

[0155] Then, the defect inspection apparatus 200 corrects the second image 25 based on the first eigenvalue and the second eigenvalue. Specifically, the defect inspection apparatus 200 calculates the first eigenvalue and the second eigenvalue λ y The average eigenvalue of (S270) is obtained, and the second image 25 is corrected using the average eigenvalue (S280).

[0156] For example, the correction unit 240 may calculate the average eigenvalue, which is the average value of the first eigenvalue and the second eigenvalue, using the following [Formula 5].

[0157] [Formula 5]

[0158]

[0159] λ x represents the first eigenvalue, λ y represents the second eigenvalue, λ m represents the average eigenvalue.

[0160] Furthermore, the correction unit 240 may apply the average characteristic value to the second image 25 to correct the second image 25. Here, the second grayscale value 26 included in the corrected second image 25 may be changed.

[0161] Reference Fig.16 The corrected image 27 as the corrected second image 25 may include a third grayscale value 28 , and the third grayscale value 28 may represent a value after the second grayscale value 26 is changed.

[0162] The correction unit 240 may generate a third matrix by matrixing the third grayscale values ​​28 included in the corrected image 27. Here, the third matrix may be m×n rows and columns composed of the third grayscale values ​​28, and may be represented by the following [Formula 6].

[0163] [Mathematical formula 6]

[0164]

[0165] M 3 represents the third matrix, and z represents the third grayscale value.

[0166] In addition, since the third matrix can be a matrix for the third grayscale value 28, and the third grayscale value 28 can be a value changed by using the average eigenvalue for the second image 25, the third matrix and the average eigenvalue can satisfy the following [Mathematical Formula 7].

[0167] [Formula 7]

[0168] M 3 ×υ=λ m ×υ

[0169] M 3 represents the third matrix, λ m represents the average eigenvalue, and υ represents the unit vector or eigenvector (Eigenvector).

[0170] In addition, although not shown, the second images 25 may be continuously acquired and overlapped. That is, the defect inspection apparatus 200 may overlap each of the second images 25a, 25b, and 25c corresponding to each of the first to third regions A to C of the stage 230 and corrected as the stage 230 moves. Fig.13 For example, the correction unit 240 corrects the second image 25 a obtained from the first area A of the table 230 , and may overlap the corrected second image 25 a to generate an overlapped image (not shown), and may output data on the overlapped image to the defect determination unit 250 .

[0171] Here, the number of overlapping images may be the same as the number of regions of the table 230. For example, if the number of regions of the table 230 is Fig.13 If there are 3 as shown, the number of overlapping images can also be 3.

[0172] Furthermore, the defect inspection device 200 compares the overlapped image with the pre-stored reference image, and can inspect whether there is a defect in a portion of the target 20 based on the comparison result. The defect determination unit 250 can compare the overlapped image (not shown) corresponding to the first area A of the table 230 with the reference image to determine whether there is a defect in a portion of the target 20.

[0173] Also, the defect inspection apparatus 200 may individually generate a determination result of whether a defect exists for each of the parts of the target 20 .

[0174] According to the above content, the following effect is achieved: when performing defect inspection on the target 20 on which wiring, semiconductor elements, etc. are mounted, not only the images of the wiring, semiconductor elements, etc. whose mounting direction is consistent with the moving direction of the table 230 become clear, but also the images of the wiring, semiconductor elements, etc. whose mounting direction is consistent with the direction different from the moving direction of the table 230 become clear.

[0175] Hereinafter, a defect inspection method of the defect inspection apparatus 200 according to an embodiment of the present invention described above will be described.

[0176] Fig.17is a flowchart for illustrating a defect inspection method according to an embodiment of the present invention.

[0177] Reference Fig.17 According to an embodiment of the present invention, a defect inspection method may include a loading judgment step (S310), a first direction movement control step (S320), a first image acquisition step (S330), a second direction movement control step (S340), a second image acquisition step (S350), an image correction step (S360) and a defect judgment step (S370), etc.

[0178] In the loading determination step ( S310 ), it is determined whether the object 20 is loaded on the table 230 .

[0179] In the first direction movement control step ( S320 ), when the target 20 is loaded, the movement of the table top 230 is controlled so that the table top 230 moves in the first direction DR1 .

[0180] In the first image acquisition step ( S330 ), light L1 is irradiated toward the target 20 while the stage 230 moves in the first direction DR1 , and a first image 23 is acquired from the light L2 reflected by the target 20 .

[0181] In the second direction movement control step ( S340 ), when the first image 23 is acquired, the movement of the table top 230 is controlled so that the table top 230 moves in the second direction DR2 perpendicular to the first direction DR1 .

[0182] In the second image acquisition step ( S350 ), the light L1 is irradiated toward the target 20 while the stage 230 moves in the second direction DR2 , and the second image 25 is acquired from the light L2 reflected by the target 20 .

[0183] In the image correction step ( S360 ), the second image 25 is corrected based on the first image 23 .

[0184] As an embodiment, in the image correction step (S360), a first grayscale value included in the first image 23 is calculated, a first matrix is ​​generated using the first grayscale value, a first eigenvalue of the first matrix is ​​calculated, and the second image 25 is corrected using the first eigenvalue.

[0185] Specifically, in the image correction step (S360), the second grayscale value included in the second image 25 is calculated, a second matrix is ​​generated using the second grayscale value, a second eigenvalue of the second matrix is ​​calculated, and the second image 25 is corrected based on the first eigenvalue and the second eigenvalue.

[0186] More specifically, in the image correction step ( S360 ), an average eigenvalue of the first eigenvalue and the second eigenvalue is calculated, and the average eigenvalue is applied to the second image 25 for correction.

[0187] In the defect determination step (S370), the corrected second image 25 is compared with a pre-stored reference image to determine whether a defect exists.

[0188] As described above, in an embodiment of the present invention, a defect inspection device and a defect inspection method thereof can be provided: when performing defect inspection of a target mounted with wiring, semiconductor elements, etc., images of wiring, semiconductor elements, etc. can be made clearer regardless of the mounting direction.

[0189] Furthermore, an embodiment of the present invention can provide a defect inspection device and a defect inspection method thereof: regardless of the direction of mounting wiring and semiconductor elements, the images of wiring and semiconductor elements can be made clear, thereby more accurately determining whether the target has defects.

[0190] Although the embodiments of the present invention are described above with reference to the accompanying drawings, a person skilled in the art with ordinary knowledge in the technical field to which the present invention belongs will understand that the present invention can be implemented in other specific forms without changing the technical ideas or essential features. Therefore, the embodiments described above should be understood in all aspects as illustrative rather than restrictive.

Claims

1. A defect inspection device, comprising: An image acquisition unit irradiates light toward a target mounted on the table and acquires an image from the light reflected from the target; a control unit, controlling the movement of the tabletop so that the tabletop moves along a first direction and a second direction perpendicular to the first direction, and controlling the operation of the image acquisition unit; a correction unit that corrects the second image based on a first image acquired by the image acquisition unit when the table moves along the first direction and a second image acquired by the image acquisition unit when the table moves along the second direction; as well as The defect judging unit compares the corrected second image with a pre-stored reference image to judge whether the object has a defect, The correction unit calculates a first gray value included in the first image, generates a first matrix using the first gray value, and calculates a first eigenvalue of the first matrix. The correction unit calculates a second grayscale value included in the second image, generates a second matrix using the second grayscale value, and calculates a second eigenvalue of the second matrix. The correction unit calculates an average eigenvalue of the first eigenvalue and the second eigenvalue, and applies the average eigenvalue to the second image to perform correction.

2. The defect inspection device according to claim 1, characterized in that: The image acquisition unit comprises: a light irradiation unit for irradiating light toward the target; at least one photographing unit, capturing light reflected from the target in units of a preset photographing area and photographing an image of the photographing area; and The image data generating unit generates image data corresponding to the image.

3. The defect inspection device according to claim 2, characterized in that: When the table moves in the first direction, the imaging unit captures a first image of an imaging region that changes with the movement of the table.

4. The defect inspection device according to claim 3, characterized in that: The first image is an image first acquired when the target is loaded on the table and the table moves along the first direction.

5. The defect inspection device according to claim 4, characterized in that: When the table moves in the second direction, the imaging unit continuously captures second images of an imaging region that changes with the movement of the table.

6. The defect inspection device according to claim 5, characterized in that: The correction unit corrects each of the second images acquired continuously based on the first image.

7. The defect inspection device according to claim 6, characterized in that: The correction unit overlaps the corrected second image and outputs data on the overlapped image to the defect determination unit. The defect determination unit compares the superimposed image with the reference image to determine whether the object has a defect.

Images