JP2019101038A - Substrate inspection device and substrate inspection method - Google Patents

Abstract

To provide a substrate inspection device and a substrate inspection method.SOLUTION: The substrate inspection device according to the present disclosure includes a light source which irradiates a coating film applied to one area on a substrate with laser light, an optical sensor which acquires light interference data by interference between reference light generated by reflecting the laser light by the surface of the coating film and measurement light obtained in such a manner that the laser light is transmitted through the coating film and scattered, and a processor which derives the thickness of the coating film corresponding to the one area on the basis of the light interference data.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a substrate inspection apparatus and a substrate inspection method.

  In the substrate processing process, the substrate may be coated to protect elements on the substrate. Such coatings can be referred to as conformal coatings. A conformal coating film thickness test can be performed to confirm that the coating film on the substrate produced by the coating is uniformly applied at a constant thickness.

  For the thickness inspection of the coating film, a two dimensional (2 Dimensional) fluorescence photography inspection can be performed. However, two-dimensional imaging examination can only qualitatively inspect the thickness of the coating film, and sometimes it is not possible to measure the accurate thickness value of the coating film. In addition, in two-dimensional imaging examination, when the coating film is thin (eg, about 30 μm), thickness measurement may be difficult.

  A method using OCT (Optical Coherence Tomography) may be used to inspect the thickness of the coating film. However, when the thickness of the coating film is inspected using OCT, the reflection by the reference mirror may cause a light saturation phenomenon to cause an error in the thickness measurement. In addition, due to components such as an OCT reference mirror, window glass or beam split, it may be difficult to miniaturize the OCT.

  The present disclosure is for solving the above-mentioned problems, and provides a technique for measuring the thickness of a coating film on a substrate.

  A substrate inspection apparatus can be proposed as one aspect of the present disclosure. A substrate inspection apparatus according to one aspect of the present disclosure includes: a light source for emitting a laser beam toward a coating film applied to a region on a substrate; and a reference generated by reflecting the laser beam by the surface of the coating film A light sensor for acquiring optical interference data due to interference between light and measurement light transmitted through the coating film by the laser light, and the coating film corresponding to the one region based on the optical interference data And a processor for deriving thickness.

  In one embodiment, the processor obtains a cross-sectional image showing a cross-section in the depth direction of the coating film based on the light interference data, and the thickness of the coating film based on a boundary on the cross-sectional image. Can be determined.

  In one embodiment, the light source may further include a moving unit for moving the light source.

  In one embodiment, the processor derives the reflectance of the surface of the coating film based on the amount of light of the reference light, and controls the moving unit to control the moving unit if the reflectance is less than a reflectance defined in advance. The light source can be moved.

  In one embodiment, the light source irradiates the laser light toward the coating film along a first direction, and the light detector travels the reference light and the measurement light traveling in a direction opposite to the first direction. The optical interference data can be acquired by capturing.

  In one embodiment, the light source can be arranged such that the laser light is irradiated directly to the surface of the coating film without transmitting the medium other than air.

  In one embodiment, the reflectance of the surface of the coating film with respect to laser light is determined by the fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film, and the fluorescent dye mixing ratio is such that the reflectance is preset. Can be set to a value that exceeds the reference value.

  In one embodiment, the coating film is formed by at least one material selected among acrylic, urethane, polyurethane, silicone, epoxy, UV (Ultra Violet) curing material and IR (Infra Red) curing material. it can.

  In one embodiment, the surface of the coating film can be formed into a curved surface.

  A substrate inspection method may be proposed as one aspect of the present disclosure. A substrate inspection method according to one aspect of the present disclosure includes: irradiating a laser beam toward a coating film applied to a region on a substrate; and a reference generated by reflecting the laser beam from the surface of the coating film. Acquiring light interference data due to interference between the light and the measurement light scattered by the laser beam through the coating film; and a thickness of the coating film corresponding to the one region based on the light interference data. And the step of

  In one embodiment, the step of deriving the thickness of the coating film comprises the steps of acquiring a cross-sectional image showing a cross-section in the depth direction of the coating film based on the light interference data; Determining the thickness of the coating film on the basis thereof.

  In one embodiment, the substrate inspection method comprises deriving the reflectance of the surface of the coating film based on the amount of light of reference light, and moving the light source if the reflectance is less than the reflectance previously defined. And the steps may be further included.

  In one embodiment, the laser light is irradiated toward the one area along a first direction, and the reference light and the measurement light can travel in a direction opposite to the first direction.

  In one embodiment, the laser light can be directly irradiated to the surface of the coating film without transmitting the medium other than air.

  In one embodiment, the reflectance of the surface of the coating film with respect to laser light is determined by the fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film, and the fluorescent dye mixing ratio is such that the reflectance is preset. Can be set to a value that exceeds the reference value.

  In one embodiment, the coating film may be formed of at least one material selected from acrylic, urethane, polyurethane, silicone, epoxy, UV curing material and IR curing material.

  In one embodiment, the surface of the coating film can be formed into a curved surface.

  According to various embodiments of the present disclosure, the substrate inspection apparatus can perform accurate thickness measurement even when the coating film is thin as less than a predetermined thickness (eg, about 30 μm).

  According to various embodiments of the present disclosure, the substrate inspection apparatus can measure the thickness of the coating film to reduce the measurement error due to the light saturation phenomenon without the component such as the reference mirror.

  According to various embodiments of the present disclosure, the substrate inspection apparatus can reduce the time required to measure the thickness of the coating film across the substrate through sampling of a specific area.

FIG. 7 is a diagram illustrating an example of a process of operating a substrate inspection apparatus according to an embodiment. FIG. 7 is a diagram illustrating an example of a process of operating a substrate inspection apparatus according to the present disclosure. FIG. 7 shows a block diagram of an inspection apparatus 10 according to various embodiments of the present disclosure. FIG. 6 illustrates a cross-sectional image and boundaries shown on the cross-sectional image, according to one embodiment of the present disclosure. It is a figure which shows the measurement range of the depth direction of test | inspection apparatus 10 by one Example of this indication. FIG. 5 illustrates the process by which processor 110 derives coating film thickness based on multiple boundaries, according to one embodiment of the present disclosure. FIG. 7 illustrates the process of processor 110 excluding certain boundaries according to predetermined criteria, according to one embodiment of the present disclosure. FIG. 7 is a diagram showing a process of adjusting a thickness measurement area based on the reflectance of a coating film according to an embodiment of the present disclosure. It is a figure which shows the process in which the test | inspection apparatus 10 samples the area | region which performs thickness measurement by the OCT part 170 according to one Example of this indication through the photography test | inspection using fluorescent dye. It is a figure which shows the process in which the test | inspection apparatus 10 additionally samples the area | region which performs thickness measurement by the OCT part 170 by element arrangement | sequence by one Example of this indication. It is a figure which shows the process in which the inspection apparatus 10 additionally samples the area | region which performs thickness measurement by the OCT part 170 by defect area | region by one Example of this indication. FIG. 10 illustrates the process of the inspection apparatus 10 additionally sampling adjacent areas of the area where thickness measurement is to be performed by the OCT part 170 according to an embodiment of the present disclosure. FIG. 1 illustrates one embodiment of a substrate inspection method that may be performed by the inspection apparatus 10 according to the present disclosure.

  The various embodiments described in this document are illustrated for the purpose of clearly illustrating the technical idea of the present disclosure, and are not intended to limit the present invention to a specific embodiment. The technical idea of the present disclosure may be combined selectively from all or a part of various modifications, equivalents, alternatives, and each embodiment described in this document. The embodiment includes the following. In addition, the scope of rights of the technical idea of the present disclosure is not limited to the various embodiments presented below or the specific description related thereto.

  Unless otherwise defined, including technical or scientific terms, the terms used in this document may have the meanings that are commonly understood by those of ordinary skill in the art to which the present disclosure belongs.

  As used in this document, such expressions as “includes”, “can be included”, “include”, “can be included”, “have”, “can have” etc. are the features of interest (eg A: function, operation or component etc.) is present, not excluding the presence of other additional features. That is, such expressions are to be understood as open-ended terms which embrace the possibility of including other embodiments.

  As used in this document, the singular forms “a”, “an” and “the” may include plural referents unless the context clearly indicates otherwise, and the same applies to the singular form in the claims.

  As used herein, the expressions "first", "second", or "first", "second" etc. refer to a plurality of homogeneous objects unless the context indicates otherwise. Are used to separate the subject from other subjects, and does not limit the order or importance between the subjects.

  “A, B, and C”, “A, B, or C”, “A, B, and / or C” or “at least one of A, B, and C” used in this document, “ Expressions such as at least one of A, B, or C, at least one of A, B, and / or C, etc., are all possible items of each listed item or listed items Can mean a combination of For example, "at least one of A or B" can refer to (1) at least one A, (2) at least one B, (3) at least one A and at least one B. .

  The expression "part" as used in this document can mean software or a component of hardware such as field-programmable gate array (FPGA), application specific integrated circuit (ASIC). However, "parts" are not limited to hardware and software. A "unit" may be configured to be stored on an addressable storage medium, and may be configured to execute one or more processors. In one embodiment, "parts" are components such as software components, object-oriented software components, class components and task components, processors, functions, attributes, procedures, subroutines, segments of program code, drivers , Firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

  As used herein, the phrase "based on" is used to describe one or more factors that affect an act or act of determination, judgment, or the like that are described in the phrase or sentence in which the expression is included. This expression does not exclude additional factors that affect the act or behavior of the decision, the judgment.

  As used herein, the term "connected" or "connected" to one component (eg, the first component) is connected to another component (eg, the second component). Not only that a component is directly connected or connected to the other component, it also means that it is connected or connected via a new other component (eg, a third component) be able to.

  As used in this document, the expression "configured to" is changed according to the context to "configured to," "having the ability to," and "to It may have a meaning such as "made", "can be made", and the like. The expression is not limited to the meaning of “specially designed in hardware”, for example, a processor configured to perform a specific operation may perform that specific operation by executing software. It can mean a generic-purpose processor capable of.

  In order to describe various embodiments of the present disclosure, an orthogonal coordinate system having X, Y and Z axes orthogonal to one another may be defined. As used herein, the expressions “X-axis direction”, “Y-axis direction”, “Z-axis direction”, etc. of the orthogonal coordinate system extend each axis of the orthogonal coordinate system unless otherwise defined differently in the description. It can mean both directions. Also, a plus sign in front of each axial direction can mean a positive direction that is any one of both directions extending in the axial direction, and a minus sign in front of each axial direction is It can mean a negative direction which is the remaining one of the two axially extending directions.

  In the present disclosure, a substrate is a plate or a container on which an element such as a semiconductor chip is mounted, and can function as a connection path of an electrical signal between the element and the element. The substrate can be used, such as for the fabrication of integrated circuits, and can be made of materials such as silicon. For example, the substrate may be a printed circuit board (PCB), and may be called a wafer according to an embodiment.

  In the present disclosure, the coating film may be a thin film formed on the substrate by a coating for protecting the device on the substrate. If the coating film is thick, the film may be broken, which may affect the operation of the substrate. Therefore, it is necessary to prevent the coating film from being broken by applying the coating film relatively thinly and uniformly. is there. In one embodiment, the coating film is formed by at least one material selected among acrylic, urethane, polyurethane, silicone, epoxy, UV (Ultra Violet) curing material and IR (Infra Red) curing material. it can. The coating film formed of the above-mentioned substance may have a high reflectance of the surface of the coating film described later and / or a backscattering rate of the coating film, as compared with the coating film which is not so.

  In the present disclosure, OCT (Optical Coherence Tomography) may be an imaging technique that captures an image within a subject using an optical interference phenomenon. An image may be acquired showing the interior of the object in the depth direction from the surface of the object using OCT. Generally, based on an interferometer, the wavelength of light used may change the resolution in the depth direction of the object. Compared with other optical technology, a confocal microscope, it can penetrate the object more deeply and acquire an image.

  Various embodiments of the present disclosure will now be described with reference to the accompanying drawings. In the accompanying drawings and the description with reference to the drawings, identical or substantially equivalent components may be provided with the same reference numerals. Also, in the following description of the various embodiments, description of identical or corresponding components may be omitted, which means that the components are not included in the embodiments. It is not something to do.

  FIG. 1 is a view showing an embodiment of a process of operating a substrate inspection apparatus according to an embodiment. The substrate inspection apparatus according to the illustrated embodiment may be a substrate inspection apparatus of a type using a reference mirror. In the illustrated embodiment, the substrate inspection apparatus can further include a light source 150, a light sensor 160, a reference mirror 172 and / or a beam split 171.

  In a substrate inspection apparatus using a reference mirror, the beam split 171 adjusts the optical path of the laser beam emitted from the light source 150, and the reference mirror 172 reflects the laser beam transmitted from the beam split 171 to generate a reference beam. can do. In the substrate inspection apparatus according to the illustrated embodiment, the laser light can be reflected by the coating film of the substrate 2 to generate measurement light. Optical interference data can be obtained from interference light of reference light and measurement light, and the substrate inspection apparatus can generate a cross-sectional image from the optical interference data to measure the thickness of the coating film.

  Specifically, the light source 150 can emit a laser beam. In one embodiment, light source 150 may direct laser light towards beam split 171. In one embodiment, the light source 150 may transmit laser light to the convex lens 173 via the optical fiber 174, and the laser light having passed through the convex lens 173 may be transmitted toward the beam split 171.

  The beam split 171 adjusts a light path to transmit a part of the laser beam transmitted from the light source 150 toward the coating film of the substrate 2 and reflects another part of the laser beam to the reference mirror 172. The light path can be adjusted to

  A part of the laser light whose optical path is adjusted to be directed to the coating film of the substrate 2 can be reflected by the coating film of the substrate 2. This reflected light can be said to be measurement light. The measurement light may travel towards the beam split 171 and be transmitted by the beam split 171 to the light detector 160. The other part of the laser light whose light path is adjusted to the reference mirror 172 can be reflected by the reference mirror 172. This reflected light can be said to be reference light. The reference light may be transmitted to the light detector 160 through the beam split 171.

  The light sensor 160 may capture interference light, which is formed when the measurement light and the reference light interfere with each other, to acquire optical interference data. In the present disclosure, in the measurement of an object according to the OCT method, optical interference data is generated by interference between the measurement light of the irradiated light reflected from the object and the reference light of the irradiated light reflected from the reference mirror or the like. Can mean data obtained from interference light. An interference phenomenon can occur due to the difference between the measurement light and the reference light (optical path, wavelength, etc.), and the light sensor can capture this interference phenomenon to acquire optical interference data. Also, based on the light interference data, a cross-sectional image can be generated that shows a cross-section in the depth direction of the coating film. Optical interference data may be referred to as an interference signal. The substrate inspection apparatus using the reference mirror can derive the thickness of the coating film applied to the substrate 2 using optical interference data from the reference light and the measurement light.

  FIG. 2 is a diagram showing an embodiment of a process of operating a substrate inspection apparatus according to the present disclosure. The substrate inspection apparatus according to the present disclosure may be embodied by the inspection apparatus 10 according to various embodiments. The substrate inspection apparatus according to the present disclosure may be a type of substrate inspection apparatus that does not use a reference mirror as described above.

  The inspection apparatus 10 according to various embodiments of the present disclosure can measure the thickness of the coating film of the substrate 2 using OCT. In one embodiment, the inspection apparatus 10 can measure the thickness of the coating film using the reflected light on the surface of the coating film without using the above-described reference mirror, predetermined window glass, or the like.

  Specifically, the inspection apparatus 10 according to the present disclosure can include the light source 150 and / or the light sensor 160 without the reference mirror 172 and the beam split 171. The light source 150 of the inspection apparatus 10 can emit a laser beam toward the coating film of the substrate 2. At this time, laser light can be emitted along the first direction. The first direction may be a direction corresponding to a straight line inclined at a predetermined angle from the normal direction of the substrate. Depending on the embodiment, the first direction may be the same as the normal direction of the substrate. The axis corresponding to the normal direction of the substrate can be said to be the z axis. The z-axis direction may be a direction corresponding to the depth direction of the coating film. As described above, the light source 150 may emit laser light directly, but may emit laser light through the optical fiber 174 and / or the convex lens 173.

  In the present disclosure, each of the x axis and the y axis may be an axis included in a plane corresponding to the surface of the substrate 2. The x and y axes can be orthogonal to one another on the plane. Also, each of the x-axis and the y-axis can be orthogonal to the aforementioned z-axis.

  The laser light can be reflected at the surface of the coating film. Specifically, the laser light can be reflected by the illustrated first surface. Also, laser light can be transmitted through the coating film and backscattered. Here, the reflected light reflected by the surface of the coating film can play the role of the reference light described above, and the scattered light can play the role of the measurement light described above. That is, in this case, the reference light is generated as the laser light is reflected by the surface of the coating film, and the measurement light may be generated as the laser light is transmitted through the coating film and scattered. The reflected light (i.e., the reference light) and the scattered light (i.e., the measurement light) can travel in the opposite direction to the first direction described above to form interference light. That is, although the irradiated laser light and the above-mentioned interference light (that is, the reflected light and the scattered light) travel along the coaxial, they can travel in opposite directions. The light sensor can capture interference light (i.e., reflected light and scattered light) traveling in the opposite direction of the first direction. The light sensor 160 can acquire optical interference data from the captured interference light. The processor 110 may obtain this light interference data from the light sensor 160 and generate a cross-sectional image based thereon to derive the thickness of the coating applied to the relevant area of the substrate 2.

  As described above, when the inspection apparatus 10 according to the present disclosure measures the thickness of the coating film, the above-described reflected light and scattered light respectively play the roles of reference light and measurement light of the substrate inspection apparatus using the above-described reference mirror. be able to. In other words, the coating film of the substrate 2 itself can play the role of the above-mentioned reference mirror 172 by the reflectance. In one embodiment, inspection apparatus 10 may not place additional components such as window glass on the coating of substrate 2. Since the inspection apparatus 10 according to the present disclosure uses the reflected light reflected by the surface of the coating film as a reference light to form interference light, an element such as window glass may not be additionally required.

  FIG. 3 is a block diagram of an inspection apparatus 10 according to various embodiments of the present disclosure. As mentioned above, the inspection apparatus 10 can include the light source 150 and the light sensor 160, and can additionally include the processor 110 and the memory 120. In one embodiment, at least one of the components of the inspection apparatus 10 may be omitted or other components may be added to the inspection apparatus 10. In addition (additionally) or alternatively, some components may be integrated and embodied, or may be embodied in one or more individuals. At least some of the external components of the inspection apparatus 10 are via a bus, general purpose input / output (GPIO), serial peripheral interface (SPI) or mobile industry processor interface (MIPI), etc. They can be linked together to pass data and / or signals.

  The light source 150 can emit laser light toward the coating film of the substrate 2 as described above. The arrangement of the light source 150, the relative position to the substrate, etc. may be variously configured. In one embodiment, the light source 150 can be disposed on the aforementioned z-axis. In one embodiment, the light source 150 can use a laser whose wavelength can be changed in a short time, and can be used to acquire optical interference data corresponding to different wavelengths. In one embodiment, inspection apparatus 10 can also include a plurality of light sources 150.

  The light sensor 160 can capture the interference light generated from the coating film by the laser light. Specifically, the light sensor 160 is configured to reflect the reflected light (i.e., the reference light) reflected by the surface of the coating film and the scattered light (i.e., the measurement light) that has been backscattered after being transmitted from the coating film to a predetermined depth. The interference light generated by can be captured. Optical interference data acquired by capturing such interference light may be used to generate a cross-sectional image based on the surface of the coating film. In one embodiment, the light sensor 160 can be disposed on the aforementioned z-axis. In one embodiment, the light sensor 160 may not be located on the z-axis, in which case certain additional components will adjust the optical path of the reflected and scattered light towards the light sensor 160 be able to. In one embodiment, inspection apparatus 10 may include a plurality of light sensors 160. The light sensor 160 may be implemented by a CCD or a CMOS. According to an embodiment, the light source 150 and the light sensor 160 may be combined and referred to as the OCT part 170 of the inspection apparatus 10.

  The processor 110 can drive software (eg, a program) to control at least one component of the test apparatus 10 coupled to the processor 110. Processor 110 may also perform a variety of operations, processing, data generation, processing, etc. that are related to the present disclosure. The processor 110 can also load data or the like from the memory 120 or store the data in the memory 120.

  The processor 110 can acquire, from the light detector 160, optical interference data by the above-mentioned interference light. The processor 110 can derive the thickness of the coating applied to a region of the substrate 2 irradiated with the laser light based on the one or more optical interference data. The process of deriving the thickness of the coating film from the light interference data will be described later.

  The memory 120 can store various data. The data stored in the memory 120 is data to be acquired, processed or used by at least one component of the inspection apparatus 10, and may include software (eg, a program). Memory 120 can include volatile and / or nonvolatile memory. Memory 120 may store one or more optical interference data obtained from light sensor 160. The memory 120 can also store element arrangement information, element density information, and electrode position information, which will be described later.

  In the present disclosure, the program is software stored in the memory 120, and an operating system for controlling the resources of the inspection apparatus 10, an application and / or various functions so that the application can utilize the resources of the inspection apparatus 10. It can include middleware provided to applications.

  In one embodiment, the inspection apparatus 10 can further include a communication interface (not shown). The communication interface may provide wireless or wired communication between the inspection device 10 and the server or the inspection device 10 and other external electronic devices. For example, the communication interface may be LTE (long-term evolution), LTE-A (LTE Advance), CDMA (code division multiple access), WCDMA (wide band CDMA), WiBro (Wireless Broadband), WiFi (wireless fidelity) Wireless communication by a method such as Bluetooth) (Bluetooth (registered trademark)), NFC (near field communication), GPS (Global Positioning System), or GNSS (global navigation satellite system). For example, the communication interface may perform wired communication by a method such as USB (universal serial bus), HDMI (registered trademark) (high definition multimedia interface), RS-232 (recommended standard 232) or POTS (plain old telephone service). it can.

  In one embodiment, processor 110 may control the communication interface to obtain information from the server. Information obtained from the server may be stored in memory 120. In one embodiment, the information acquired from the server may include element arrangement information, element density information, electrode position information, and the like described later.

  In one embodiment, the inspection apparatus 10 may further include an additional light source 130 and an additional light sensor 140 described later. The additional light source 130 and the additional light sensor 140 can be used to acquire a two-dimensional image of the coating film of the substrate 2 and measure the thickness of the coating film.

  In one embodiment, the inspection apparatus 10 can further include a moving unit described later. The moving unit can move the light source 150 to the OCT part (170) along the aforementioned x, y, z axes.

  In one embodiment, the inspection apparatus 10 can further include an input device (not shown). The input device may be a device that receives an input of data to be communicated from the outside to at least one component of the inspection apparatus 10. For example, the input device can include a mouse, a keyboard, a touch pad, and the like.

  In one embodiment, inspection apparatus 10 may further include an output device (not shown). The output device may be a device for providing various data such as the inspection result of the inspection device 10 and the operation state to the user in a visual form. For example, the output device can include a display, a projector, a hologram device, and the like.

  In one embodiment, inspection apparatus 10 may be of various forms. For example, the inspection device 10 may be a portable communication device, a computer device, a portable multimedia device, a wearable device, or a combination of one or more of the aforementioned devices. The inspection apparatus 10 of the present disclosure is not limited to the above-described apparatus.

  Various embodiments of inspection apparatus 10 according to the present disclosure may be combined with one another. Each embodiment is combined according to the number of cases, and an embodiment of the inspection apparatus 10 made in combination is also within the scope of the present disclosure. Also, the internal / external components of the inspection apparatus 10 according to the present disclosure described above can be added, changed, substituted or deleted according to the embodiment. Also, the internal / external components of the inspection apparatus 10 described above may be embodied by hardware components.

  FIG. 4 is a diagram showing a cross-sectional image and boundaries shown on the cross-sectional image according to one embodiment of the present disclosure. As mentioned above, the processor 110 can derive the thickness of the coating applied to the predetermined area of the substrate 2 from the acquired optical interference data. The processor 110 can generate a cross-sectional image from the optical interference data and use the information on the cross-sectional image to derive the thickness of the coating film.

  In the present disclosure, the cross-sectional image can mean a two-dimensional image of a cross section in the depth direction of the target (coating film) in measurement of the target by the OCT method. Cross-sectional images may be generated based on the measured optical interference data. The cross-sectional image can have a boundary line (boundary pattern) corresponding to the interface between air and the coating film and the coating film and the substrate.

  Specifically, the processor 110 may obtain a cross-sectional image as illustrated through the optical interference data captured by the light sensor 160. The cross-sectional image may be an image showing a cross section in the −z-axis direction, ie, the depth direction, with respect to the substrate 2 and the coating film. That is, the cross-sectional image can show the inside of the coating film and the substrate transmitted in the depth direction from the surface of the coating film.

  The illustrated cross-sectional image 4010 may be a cross-sectional image that may be obtained by a substrate inspection apparatus using the reference mirror described above. Cross-sectional image 4010 can have one or more border lines 4050. Each of the boundaries 4050 is an interface between air and the coating film, that is, a boundary corresponding to the surface of the coating film, or an interface between the coating film and the substrate 2 or electrode on which the coating film is applied. It may be a corresponding border. The substrate inspection apparatus using the reference mirror can derive the thickness of the coating film using the distance between the boundaries corresponding to the respective boundary surfaces.

  Specifically, in the case of a substrate inspection apparatus using a reference mirror, a cross-sectional image 4010 based on the reference mirror surface can be acquired. The substrate inspection apparatus can determine the boundary line indicating the interface between the air and the coating film from the cross-sectional image 4010 shown. Also, the substrate inspection apparatus can determine the boundary line indicating the boundary surface between the coating film and the substrate 2 on which the coating film is applied from the cross-sectional image 4010. The substrate inspection apparatus can derive the determined vertical distance between both boundaries on the cross-sectional image 4010, and determine the vertical distance as the thickness of the coating film.

  On the other hand, in the case of using the substrate inspection device according to the present disclosure (for example, the inspection device 10), a cross-sectional image 4020 based on the coating film surface can be acquired. Cross-sectional image 4020 can have one or more boundary lines 4040. One of the boundaries 4040 may be a boundary corresponding to the interface between the coating film and the substrate 2 to which the coating film is applied. The processor 110 of the inspection apparatus 10 can use the distance between the boundary 4040 and the upper side 4030 of the cross-sectional image 4020 to derive the thickness of the coating film.

  In the case of the inspection apparatus 10 according to the present disclosure, the processor 110 can sense a boundary 4040 that indicates the interface between the coating film and the substrate 2 on which the coating film is applied. In one embodiment, the processor 110 can determine the boundary shown for the first time in the depth direction from the upper side of the cross-sectional image 4020 as the boundary 4040. Further, in the case of the inspection apparatus 10, in order to generate optical interference data using the reflected light reflected from the surface of the coating film, the cross-sectional image takes the surface of the coating film as the origin and the -z axis direction from the surface of the coating film, , A cross section in the depth direction can be shown. Accordingly, the upper side 4030 of the cross-sectional image 4020 acquired by the inspection apparatus 10 can correspond to the surface of the coating film. The processor 110 can derive the longitudinal distance between the sensed boundary line 4040 and the top side 4030 of the cross-sectional image 4020, and determine the longitudinal distance as the thickness of the coating film. In one embodiment, the processor 110 may apply a predetermined scaling factor to the derived longitudinal distance to determine the derived value as the thickness of the coating film.

  In one embodiment, in the measurement of the thickness of the coating on the substrate 2 using OCT, the laser light, the reflected light, the scattered light and / or the interference light move through a non-air vacuum or other medium. You can also. That is, the light source 150 can be disposed such that the laser light is directly irradiated to the surface of the coating film without transmitting the medium other than air.

  FIG. 5 is a diagram showing a measurement range in the depth direction of the inspection apparatus 10 according to an embodiment of the present disclosure. The illustrated cross-sectional image 5010 may be a cross-sectional image acquired by the substrate inspection apparatus using the reference mirror described above. The cross-sectional image 5010 can have a boundary indicating the interface between air and the coating and a boundary indicating the interface between the coating and the substrate (PCB). Also, the illustrated cross-sectional image 5020 may be a cross-sectional image acquired by a substrate inspection apparatus (eg, inspection apparatus 10) according to the present disclosure. The cross-sectional image 5020 can have a border indicating the interface between the coating and the substrate (PCB).

  In one embodiment, the cross-sectional image 5010 may be larger than the cross-sectional image 5020. That is, the sectional image 5010 has a larger amount of data than the sectional image 5020. This is different from the case of using the reference mirror in the case of measurement by the inspection apparatus 10, because the reflected light reflected from the surface of the coating film is used as the reference light, the measurement range in the depth direction (-z-axis direction) is the coating film To be limited to starting with the surface of the.

  In the illustrated cross-sectional view 5030, in the case of a substrate inspection apparatus using a reference mirror, a measurement range 5040 in which all differences in height due to the elements mounted on the substrate 2 are required is necessary to obtain meaningful measurement results. Sometimes. However, in the case of the measurement of the thickness of the coating film using the inspection apparatus 10, the measurement result of the meaningful thickness can be obtained even with the measurement range 5050 of the maximum expected thickness of the coating film alone. In other words, since the inspection apparatus 10 can reduce the measurement range in the depth direction required to measure the thickness of the coating film, it can reduce the computing capacity required for processing the measurement results and the memory required for storage. it can.

  Further, in the case of measuring the thickness of the coating film using the inspection apparatus 10, since the reference mirror is not used, the possibility of the occurrence of measurement error due to the saturation phenomenon of the reflected light can be reduced. When the light output of the irradiation light exceeds a certain amount, the amount of reflected light also increases, and the interference signal can be saturated. When saturated, the interference signal will be shown regardless of the interference signal generated by the measurement object, which may hinder accurate measurement. Such a saturation phenomenon may occur better when using a high reflectivity reference mirror. The inspection apparatus 10 can reduce measurement errors due to saturation phenomena by eliminating the use of reference mirrors.

  FIG. 6 is a diagram showing how the processor 110 derives the coating film thickness based on a plurality of boundaries according to an embodiment of the present disclosure. In one embodiment, the inspection apparatus 10 can derive the thickness of the coating film corresponding to the predetermined area using a plurality of cross-sectional images acquired in advance for the predetermined area stored in the memory. For this purpose, a plurality of cross-sectional images can be obtained in advance and stored in a memory through a plurality of measurements. Thus, the inspection apparatus 10 can derive the thickness of the coating film while minimizing the influence of noise.

  As mentioned above, processor 110 may acquire one cross-sectional image based on the one or more optical interference data. The substrate inspection apparatus may repeat the measurement a plurality of times to obtain a plurality of cross-sectional images 6010 for a predetermined area of the substrate, and the plurality of cross-sectional images may be stored in a memory. Each of the plurality of cross-sectional images 6010 can show a cross section of the coating film of the substrate 2 in the −z axis, ie, the depth direction. Each of the plurality of cross-sectional images 6010 can have a boundary 6020 that indicates an interface between the coating film and the substrate 2.

  The processor 110 can obtain multiple border lines 6020 from each of the cross-sectional images 6010. The processor 110 can determine one of the plurality of boundary lines 6020 as a boundary line 6030 indicating the boundary surface between the coating film and a region of the substrate 2 on which the coating film is applied. The processor 110 can derive the thickness of the coating film in the above-described manner based on the determined boundary line.

  In one embodiment, the processor 110 derives the mean, median or mode of the plurality of boundaries 6020, and the boundaries by the mean, median or mode are: It can be determined as a boundary 6030 indicating the interface between the coating film and the substrate 2. The processor can derive the thickness of the coating film corresponding to one area of the boundary surface based on the determined boundary line 6030.

  In the present disclosure, the mean value may be the total number of samples divided by the total number of samples after adding the values of all samples. In the present disclosure, median can mean the value that is in the middle of the values of all samples. If the values of the samples are arranged from small numbers to large numbers and the number of samples is odd, the value located in the middle is taken as the median, and if the number of samples is even, the average value of the two values located in the middle is used It can be median. In the present disclosure, the mode value can mean the highest frequency of the sample values. In particular, in the present disclosure, the average value, the median value, or the mode value of the boundary can mean the average value, the median value, or the mode of the position coordinates of the boundary line in the cross-sectional image. That is, when the cross-sectional image is viewed in a plane formed by the x and y axes, each point of the boundary in the cross-sectional image can have x and y coordinate values. An average value, a median value or a mode value of x and y coordinate values respectively possessed by the plurality of boundary lines 6020 in the plurality of cross-sectional images 6010 can be derived, and the boundary line by the derived coordinate values is the aforementioned average value, It may be a median or mode boundary 6030.

  FIG. 7 is a diagram illustrating the process of the processor 110 excluding a partial boundary according to a predetermined criterion according to one embodiment of the present disclosure. In one embodiment, the processor 110 derives the average value of the plurality of boundary lines 6020 described above, excludes the boundary lines deviating from the derived average value by the predetermined ratio or more, and then removes the coating film with only the remaining boundary lines. The boundaries underlying the derivation of thickness can be determined. This may be to perform coating film thickness measurement excluding values due to obvious measurement errors by excluding boundaries that greatly deviate from a certain range among the plurality of boundaries 6020. Through this, more accurate thickness measurement may be possible.

  In particular, processor 110 may derive a first average value for a plurality of boundary lines 6020. The process of deriving the mean value of the boundary can be performed as described above. The processor 110 may exclude, from among the plurality of boundary lines 6020, a boundary line 7030 that deviates from the first average value derived by a ratio that is already defined. That is, assuming that the range by the predetermined ratio of the derived first average value is a region between dotted lines 7020 shown, the boundary 7010 included in the region is maintained, and the boundary 7030 deviates from the region. Can be excluded from further processing. The processor 110 can derive a second average value of the remaining boundary 7010 excluding the boundary 7030 that deviates by more than the previously defined ratio. The process of deriving the mean value of the boundary can be performed as described above. The processor 110 can determine the boundary line by the derived second average value as the boundary line indicating the boundary surface between the coating film and the substrate 2. The processor can derive the thickness of the coating film corresponding to a region of the boundary surface based on the determined boundary line.

  In one embodiment, processor 110 may perform operations to eliminate predetermined boundaries, as described above, using a median or mode that is not an average. For example, the processor 110 derives the first median of the plurality of boundaries 6020, excludes the boundary deviating from the first median by a predetermined ratio, and limits the boundary by the second median of the remaining boundaries as the coating film It can be determined as the borderline on which to derive the thickness of. The same is true for the mode value. In one embodiment, mean, median and mode may be used in combination with each other.

  FIG. 8 is a diagram showing a process of adjusting a thickness measurement area based on the reflectance of a coating film according to an embodiment of the present disclosure. In one embodiment, when the reflectance of the surface of the coating film is equal to or higher than a predetermined reference value, the inspection apparatus 10 without using a reference mirror may be used. The predetermined reference value may be the minimum reflectance required for the surface of the coating film to play the role of the reference mirror 172. In the thickness measurement without using the reference mirror of the present disclosure, the reflectance of the surface of the coating film is the reflected light (ie, reference light) generated by being reflected from the surface of the coating film and the laser light irradiated to the coating film It can mean the ratio between.

  In one embodiment, the inspection apparatus 10 derives the reflectance of the coating film based on the amount of light reflected (i.e., reference light) by the surface of the coating film, and moves the light source 150 to the OCT part 170 by the reflectance. Measurement can be performed. In order to acquire optical interference data based on the reflectance of a coating film, the inspection apparatus 10 which does not use a reference mirror acquires a more meaningful measurement result by finely adjusting a measuring object point with the reflectance of a coating film. can do.

  Specifically, when capturing the interference light due to the reflected light (i.e., the reference light) and the scattered light (i.e., the measurement light) described above, the light sensor 160 can measure the light amount of the reference light. The processor 110 can derive the reflectance in the z-axis direction in the relevant region of the surface of the coating film based on the measured light intensity of the reference light by the coating film. The reflectance in the z-axis direction can mean a ratio at which the irradiated laser light is reflected in the + z-axis direction.

  The processor 110 determines that one or more optical interference data formed by the reference light is valid optical interference data when the derived reflectance is equal to or higher than the already defined reflectance. Interferometric data can be used to derive coating film thickness. The reflectance defined above is the minimum reflectance required for the coating film to act as a reference mirror, and may be the above-mentioned predetermined reference value.

  The processor 110 controls the light source 150 or the OCT part so that the laser light is emitted toward the other area 8020 adjacent to the initial measurement target area 8010 if the derived reflectance is less than the already defined reflectance. 170 can be moved. In one embodiment, the inspection apparatus 10 can further include a moving unit. The moving unit can move the light source 150 to the OCT part 170 in the x-axis, y-axis and / or z-axis directions. As described above, the x-axis and the y-axis are respectively axes included in a plane corresponding to the surface of the substrate 2 and can be orthogonal to each other on the plane, and the z-axis corresponds to the normal direction of the substrate It can be an axis. Each of the x-axis and the y-axis can be orthogonal to the aforementioned z-axis. The processor 110 controls the moving unit to direct the light source 150 or the OCT part 170 in the x-axis and / or y-axis direction so that the laser light is irradiated toward another area 8020 adjacent to the initial measurement target area 8010. It can be moved.

  In one embodiment, processor 110 controls the mover to adjust the position of light source 150 or OCT part 170 on the z-axis based on the resolution of the acquired one or more captured interference lights. be able to. That is, the moving unit can move the light source 150 or the OCT part 170 in the z-axis direction according to the resolution of the captured interference light. Since the interference light is a capture of the interference phenomenon due to the reflected light (that is, the reference light) and the scattered light (that is, the measurement light) described above, laser light, reflected light, scattered light It can be determined by the phase difference due to the movement path of The processor 110 can control the moving unit to adjust the position of the light source 150 or the OCT part 170 on the z-axis to perform adjustment for acquiring an interference signal of clearer interference light.

  In the illustrated measurement area adjustment process 810, the OCT part 170 can be moved by the moving unit. Thereby, the area to be measured by the OCT part 170 or the area 8010 to which the laser light is irradiated can be moved to the x axis or the y axis. This may be because the reflectance of the coating film in the existing region 8010 has not reached a predetermined standard. The new irradiation area 8020 can be determined as the adjacent area where the measured thickness of the coating film corresponding to the new irradiation area 8020 is considered or approximate to the thickness of the coating film corresponding to the existing area 8010 . The adjacent area to one area will be described later. Also, unlike the existing region 8010, the new irradiation region 8020 can be determined as a region where the reflectance in the + z-axis direction of the reference light is greater than or equal to a predetermined reference. In one embodiment, the new irradiation area 8020 may be determined as an area where the reflectance of the reference light in the + z-axis direction is higher by a predetermined ratio or more than the existing area 8010.

  When this process is viewed in cross section (820), the light source 150 is moved by the moving unit, and laser light can be irradiated from the existing irradiation area 8010 to the new irradiation area 8020. In the illustrated embodiment, the existing irradiation area 8010 has a reflectance of the coating film in the + z-axis direction less than a predetermined standard. This may be because the surface of the coating film of the existing irradiation area 8010 is not parallel to the normal to the substrate, and is inclined at a certain angle or more. Also, based on the resolution of the captured interference light, the moving unit can move the light source 150 or the OCT part 170 in the z-axis direction.

  In one embodiment, the irradiation angle of the laser beam to be irradiated may be adjusted so that the reflectance of the surface of the coating film is equal to or higher than a reference value. In one embodiment, the laser beam can be irradiated to a region in which the surface of the coating film is parallel to the substrate such that the reflectance of the surface of the coating film is equal to or higher than a reference value.

  In one embodiment, the reflectance of the surface of the coating film can be determined by the fluorescent dye mixture ratio of the coating film. In one embodiment, the coating film mixed with the fluorescent dye may have a higher reflectance on the surface of the coating film than a substrate not. The higher the fluorescent dye mixing ratio of the coating film, the higher the reflectance of the surface of the coating film can be. That is, when the coating film in which the fluorescent dye is mixed is used, the reflectance of the surface of the coating film becomes high, whereby thickness measurement can be easily performed by the inspection apparatus 10 without using the reference mirror. In one embodiment, the fluorescent dye mixing ratio of the coating film can be set to a value that causes the reflectance of the surface of the coating film to exceed a preset reference value. According to the embodiment, this reference value may be the minimum reflectance required for the surface of the coating film to play the role of the reference mirror 172, or even a value arbitrarily set by the intention of the practitioner. Good.

  In one embodiment, the backscattering rate of the coating film can also be determined by the fluorescent dye mixture ratio of the coating film. In one embodiment, the coating film mixed with the fluorescent dye may have a high backscattering rate of the coating film as compared to the non-fluorescent substrate. In the thickness measurement by the inspection apparatus 10 without the reference mirror of the present disclosure, the backscattering rate of the coating film is between the aforementioned scattered light (that is, measurement light) backscattered and the laser beam irradiated to the coating film. It can mean a ratio. The higher the fluorescent dye mixing ratio of the coating film, the higher the backscattering ratio of the coating film may be. That is, when the coating film in which the fluorescent dye is mixed is used, the backscattering rate of the coating film becomes high, whereby the thickness measurement by the inspection apparatus 10 without using the reference mirror can be easily performed. In one embodiment, the fluorescent dye mixing ratio of the coating film can be set to a value that causes the backscattering ratio of the coating film to exceed a preset reference value.

  In one embodiment, the surface of the coating film can be formed into a curved surface. In one embodiment, the surface of the coating film may be formed into a curved surface having a convex curved surface, a concave curved surface, or an arbitrary shape with respect to the substrate. In one embodiment, when the surface of the coating film is a curved surface, thickness measurement by the inspection apparatus 10 without using a reference mirror can be easily performed as compared with the case where the surface of the coating film is a flat surface.

  FIG. 9 is a diagram showing a process in which the inspection apparatus 10 samples a region where thickness measurement is to be performed by the OCT part 170 through a photographing inspection using a fluorescent dye according to an embodiment of the present disclosure. In one embodiment, the inspection apparatus 10 performs a photographic inspection using a fluorescent dye on the entire area of the substrate, derives a specific area according to a predetermined standard based on the inspection result, and performs OCT on the derived area. The thickness of the coating can be measured.

  The inspection apparatus 10 can first perform a photographic inspection using a fluorescent dye on the substrate 2. The photography exam may be a fluorescence photography exam. A fluorescent dye may be mixed in advance in the coating film applied on the substrate 2 for this inspection. According to one embodiment, the inspection apparatus 10 according to the present disclosure may further include the additional light source 130 and / or the additional light sensor 140. The additional light source 130 of the inspection apparatus 10 can emit ultraviolet light toward the coating film of the substrate. The irradiated ultraviolet light can excite the fluorescent dye mixed in the coating film to generate fluorescence. The additional light sensor 140 of the inspection apparatus 10 can capture the fluorescence to obtain a two-dimensional image of the coating on the substrate. The two-dimensional image may be a two-dimensional fluorescence image according to the embodiment.

  The inspection apparatus 10 can derive one or more areas 3 on the substrate 2 according to predetermined criteria based on the results of the photographic inspection. The inspection apparatus 10 can derive the coating amount of the coating film applied to the substrate 2 from the two-dimensional image. The inspection apparatus 10 can acquire luminance information for each of a plurality of regions of the substrate 2 from the acquired two-dimensional image. When irradiated with ultraviolet light, the amount of fluorescent dye may show different brightness in each region of the coating. The inspection apparatus 10 can use the brightness of each area to derive the coating amount of the coating film in each area.

  Thereafter, the inspection apparatus 10 can derive the constant region 3 based on the application amount. For example, an area in which the application amount is equal to or less than a predetermined standard can be derived as the constant area 3. The inspection apparatus 10 can additionally perform thickness measurement using the OCT part 170 as described above on the derived area 3. The OCT part 170 of the inspection apparatus 10 acquires optical interference data for the derived area 3 and measures the thickness of the coating film applied to the area 3 on the substrate based on the acquired optical interference data. be able to.

  In one embodiment, the additional light source 130 may be disposed to irradiate ultraviolet light toward the substrate, and the relative position of the additional light source 130 to the substrate, the irradiation angle of ultraviolet light, the brightness of the ultraviolet light, etc. It can be configured in various ways. In one embodiment, inspection apparatus 10 may include a plurality of additional light sources 130. In one embodiment, the additional light sensor 140 can capture fluorescence generated from the coating film by ultraviolet light. In one embodiment, inspection apparatus 10 may include a plurality of additional light sensors 140. The additional light sensor 140 may be embodied by a charged coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS).

  FIG. 10 is a diagram showing a process in which the inspection apparatus 10 additionally samples an area where thickness measurement is to be performed by the OCT part 170 according to an element arrangement according to an embodiment of the present disclosure. In one embodiment, the processor 110 derives an area 4 in which the arrangement of the element is the same as or similar to the area 3 in which the application amount derived through the two-dimensional image is equal to or less than the already set amount. The thickness for this area 4 can be derived. In other words, the processor 110 can derive a region having the same or similar array of elements based on the element array information, and perform thickness measurement using the OCT on the area. The same or similar regions of the element arrangement may have similar thickness values of the applied coating film. An area which is the same as or similar to one certain area and the element arrangement can have a similar coating film thickness. In the present disclosure, the element arrangement information may be information indicating the arrangement of the elements arranged on the substrate 2. The element array information can indicate information such as the position, the direction, and the size of the element mounted on the substrate 2 on the substrate 2.

  First, the processor 110 can derive an area 3 in which the application amount obtained through the two-dimensional image is less than or equal to the already set amount, as described above. In one embodiment, processor 110 may use OCT part 170 to measure the thickness for this area 3. In addition to this, the processor 110 can derive an area 4 on the substrate 2 in which the derived area 3 and the element arrangement are the same. The area 4 can be selected in an area (i.e., an area other than the first area) in which the application amount derived through the two-dimensional image exceeds the set amount. The processor 110 can derive the area 4 based on the above-described element arrangement information. The processor 110 can use the OCT part 170 to derive the additionally derived thickness for the area 4 in question. The processor 110 can control the light source 150 and the light sensor 160 to obtain optical interference data generated by the laser light reflected from the area 4. The processor 110 can derive the thickness for the coating applied to the area 4 based on the acquired optical interference data. In the present disclosure, the fact that the processor 110 controls the light source 150 and the light sensor 160 to acquire optical interference data of a region means that the light source 150 emits laser light toward the region and the light sensor 160 Can mean that the optical interference data by the interference light generated from the one area is acquired.

  In one embodiment, the processor 110 may derive a region 4 in which the element arrangement is similar to the region 3 derived from the two-dimensional image, and perform thickness measurement using OCT on the region 4. Here, whether or not the element arrangement is similar can be determined based on the element arrangement information for both regions 3 and 4. The processor 110 calculates the similarity of the element arrangement to both areas based on the area occupied by the element in the areas 3 and 4, the arrangement, the type, the form of the element, the electrode position of the element, etc. Whether or not the element arrangements in the regions are similar can be determined.

  In one embodiment, the processor 110 adjusts the aforementioned luminance information according to the arrangement of elements on the substrate 2 and the degree to which the elements are dense, and derives the coating film application amount of the area based on the adjusted luminance information. Can. Specifically, the processor 110 can obtain element arrangement information indicating the arrangement of the elements on the substrate 2 from the memory 120. The processor 110 can derive element density information for each area on the substrate 2 based on the above-described element arrangement information. The processor 110 may adjust the luminance information derived from the two-dimensional image based on the element density information. The application of the fluorescent dye may not be uniform in the region of the substrate 2 where the element density is high. In areas where the element density is high, ie, where the elements are dense, the brightness can be measured high due to the accumulation of the fluorescent dye. The processor 110 can adjust the acquired luminance information in consideration of distortion of luminance due to the element density. Such adjustment may use stored information indicating the relationship between the element density and the luminance, and this information may be databased and stored in the memory 120. The processor 110 can derive the application amount for each of the areas on the substrate 2 based on the adjusted luminance information.

  FIG. 11 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples a region where thickness measurement is performed by the OCT part 170 according to a defect region according to an embodiment of the present disclosure. In one embodiment, the processor 110 derives an area 5 determined to be defective on the substrate 2 based on the element arrangement information and the two-dimensional image, and controls the OCT part 170 to derive a thickness for this area. Can. Portions of the substrate 2 or the coating film where there are predetermined defects, such as cracks, peeling, asperities, bending, etc., may cause errors in the measurement of the amount of application through the two-dimensional photographic inspection. Thereby, the area 5 determined to have a predetermined defect based on the element arrangement information and / or the two-dimensional image may additionally be subjected to the measurement of the thickness of the coating film using the OCT part 170.

  The processor 110 can determine, based on the element arrangement information and / or the two-dimensional image acquired from the memory 120, an area 5 which is determined to have a predetermined defect on the substrate 2. The two-dimensional image may be a picture taken of the form of the actual substrate 2 and the coating film. The element arrangement information can indicate the form of the substrate 2 according to a predetermined specification and the expected application form of the coating film. The processor 110 can compare element arrangement information with a two-dimensional image to determine an area in which the current substrate 2 and the coating film have a feature that deviates from a predetermined standard. That is, processor 110 may determine that the feature is defective. The processor 110 can derive the area 5 in which the defect exists.

  Processor 110 may use OCT part 170 to derive the thickness for derived region 5. The processor 110 can control the light source 150 and the light sensor 160 to obtain optical interference data generated by the laser light reflected from the area 5. The processor 110 can derive a thickness for the coating applied to the area 5 based on the acquired light interference data.

  In one embodiment, the derivation of the additional measurement target area based on the defect area can be performed independently of the derivation of the additional measurement target area based on the two-dimensional image described above.

  Also, in one embodiment, the processor 110 derives an area including the electrode portion based on electrode position information indicating the position of the electrode of the element on the substrate 2 and controls the OCT part 170 to add an area to this area. Thickness measurements can be made. In the present disclosure, the electrode position information can indicate the position of the electrode that the element has on the substrate 2. For example, each of the devices can have an electrode portion for connecting the device and the fine wiring on the substrate. This electrode can also be referred to as the element or the leg of the chip. The electrode position information can indicate where the electrode of the element is located on the substrate 2. In general, in the electrode portion of the device, there may be a phenomenon in which the fluorescent dye may be clumped due to the crowding of the legs of the device, whereby thickness measurement based on a two-dimensional image may not be accurate. As a result, additional thickness measurement using OCT can be performed on the portion where the electrode of the element is located, and the accuracy of the entire thickness measurement process can be enhanced.

  Based on the electrode position information acquired from the memory 120, the processor 110 can know where the electrode of the element is located on the substrate 2. The processor 110 can derive an area on the substrate 2 where the electrodes are located. In one embodiment, the area can be selected in an area (i.e., an area other than the first area) in which the application amount obtained through the two-dimensional image exceeds the set amount.

  Processor 110 may use OCT part 170 to derive a thickness for the derived area. The processor 110 can control the light source 150 and the light sensor 160 to obtain optical interference data generated by the laser light reflected from the area. The processor 110 can derive a thickness for the coating applied to the area based on the acquired optical interference data.

  FIG. 12 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples an adjacent area of the area where the thickness measurement is performed by the OCT part 170 according to an embodiment of the present disclosure. In the area on the substrate 2 derived according to the various embodiments of the present disclosure, ie in the area 7 where additional thickness measurement is performed using OCT, the inspection apparatus 10 also applies to the adjacent area 8 of the area 7 Additional thickness measurements can be made using OCT.

  The derived area 7 is where, in terms of the accuracy of the measurement of the thickness of the coating film, thickness measurement with OCT can be performed in addition to two-dimensional photography inspection. The adjacent area of the area 7 may have similar characteristics to the area 7 in relation to the substrate 2 or the coating film. This allows additional thickness measurements using OCT to be performed on adjacent areas to ensure the accuracy of the overall thickness measurement process.

  Here, the adjacent area can mean an area located adjacent to the area 7 when the substrate 2 is divided into a plurality of areas. In one embodiment, the adjacent area can mean an area having a boundary with the area 7 among a plurality of areas. In one embodiment, the adjacent area can mean an area located within a constant radius with respect to the center of the area 7 among the plurality of areas. In one embodiment, when the axes corresponding to the horizontal direction and the vertical direction of the substrate are x and y axes, respectively, the adjacent area is the + x axis direction, -x axis direction, + y axis direction, and -y axis of the area 7. It may be an area located in a direction and sharing a boundary with the area 7. In one embodiment, the adjacent area may include, among the plurality of areas, an area sharing a vertex with the area 7 and located diagonally.

  In one embodiment, the processor 110 may again perform thickness measurement using OCT based on the application amount derived from the two-dimensional image and the thickness value measured by the OCT part 170. According to the embodiment, the difference value between the qualitative thickness value of the area coating film which can be derived from the application amount and the thickness value measured by OCT is derived, and the difference value is equal to or more than the already defined value. Thickness measurement using OCT can be performed again on the area concerned. Also, according to the embodiment, based on the derived application amount and thickness value, thickness measurement can be performed again if the two values do not meet the predetermined criteria. Here, the predetermined standard is determined that at least one value of the derived coating amount or thickness is erroneously measured when the relationship between the coating amount and the thickness which has already been measured is considered. It can be the standard used to That is, if it is determined that there is an error in the measurement when considering the application amount and the thickness value, the measurement can be performed again. Also, in one embodiment, the processor 110 may apply to the adjacent area of the area based on the application amount of the area derived from the two-dimensional image and the thickness value of the area measured by the OCT part 170, The OCT part 170 can be controlled to remeasure the thickness.

  FIG. 13 is a diagram illustrating an example of a substrate inspection method that may be performed by the inspection apparatus 10 according to the present disclosure. Although each step of the method or algorithm according to the present disclosure is described in sequential order in the illustrated flowchart, each step may be performed according to any order that can be arbitrarily combined according to the present disclosure other than being performed sequentially. it can. The description with respect to this flow chart does not exclude making changes or modifications to the method or algorithm, and does not mean that any step is essential or desirable. In one embodiment, at least some of the steps can be performed in parallel, iteratively or heuristically. In one embodiment, at least some of the steps may be omitted or other steps may be added.

  The inspection apparatus 10 according to the present disclosure may perform a substrate inspection method according to various embodiments of the present disclosure when performing a substrate inspection. A substrate inspection method according to an embodiment of the present disclosure includes irradiating a laser beam toward a coating film applied to a region on a substrate, S100, a reference light and a coating film generated by reflection from the surface of the coating film. Acquiring optical interference data due to interference between measurement light transmitted through and scattering the measurement light, and / or deriving a thickness of the coating film corresponding to the one region based on the optical interference data. be able to.

  In operation S100, the light source 150 of the inspection apparatus 10 may emit laser light toward the coating film applied to a region on the substrate. In step S200, the light sensor 160 acquires optical interference data due to interference between the reference light generated by the laser light reflected by the surface of the coating film and the measurement light scattered by the laser light transmitted through the coating film. can do. In operation S300, the processor 110 may derive the thickness of the coating film corresponding to the above-mentioned area based on the light interference data.

  In one embodiment, the step S300 of deriving the thickness of the coating film is a step of acquiring a cross-sectional image showing the cross-section in the depth direction of the coating film based on the light interference data and / or on the cross-sectional image The step of determining the thickness of the coating film can be included based on the boundaries.

  In one embodiment, the step S300 of deriving the thickness of the coating film comprises: acquiring the plurality of cross-sectional images previously acquired for the one area from the memory; and / or the plurality of cross-sectional images by the processor 110. Determining a reference boundary from the plurality of boundaries, and deriving the thickness of the coating film corresponding to the one area based on the reference boundary.

  In one embodiment, the reference boundary may be a boundary of one of a mean, a median and a mode for the plurality of boundaries.

  In one embodiment, the reference boundary may be a boundary by an average value of boundaries satisfying predetermined criteria among the plurality of boundaries.

  In one embodiment, the substrate inspection method comprises the steps of the photodetector 160 deriving the reflectance of the surface of the coating film based on the light intensity of the reference light and / or the light source if the reflectance is less than the reflectance previously defined. The method may further include moving the This movement can be performed by the moving unit described above.

  In one embodiment, the laser light is emitted along the first direction toward the aforementioned area, and the reference light and the measurement light travel in the opposite direction of the first direction and are captured by the light sensor it can. In one embodiment, the laser light can be irradiated directly on the surface of the coating film without transmitting the medium other than air.

  Various embodiments of the present disclosure may be embodied in software in a machine-readable storage medium readable by a machine. The software may be software for implementing various embodiments of the present disclosure. Software may be inferred from various embodiments of the present disclosure by programmers in the technical field to which the present disclosure belongs. For example, the software may be a program that includes instructions (eg, code or code segments) readable by the device. The device is a device operable by an instruction word called from a storage medium, and may be, for example, a computer. In one embodiment, the device may be an inspection apparatus 10 according to an embodiment of the present disclosure. In one embodiment, the processor of the device may execute the called command to cause the component of the device to perform the function corresponding to the command. In one embodiment, the processor may be processor 110 according to an embodiment of the present disclosure. Storage medium can mean any kind of recording medium on which data can be stored, which can be read by a device. The storage medium may include, for example, a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy (registered trademark) disk, an optical data storage device, and the like. In one embodiment, the storage medium may be memory 120. In one embodiment, the storage medium may be embodied in a distributed form in a computer system or the like connected to a network. The software can be distributed stored in a computer system or the like and executed. The storage medium may be a non-transitory storage medium. A non-transitory storage medium means a tangible medium regardless of whether the data is stored semipermanently or temporarily, and does not include a signal propagated to the transitory.

  Although the technical idea of the present disclosure has been described above by various embodiments, the technical idea of the present disclosure can be various substitutions that can be made as long as those of ordinary skill in the technical field to which the present disclosure belongs can be understood. , Including transformations and modifications. Also, such substitutions, changes and modifications are to be understood as being within the scope of the appended claims.

110 processor 150 light source 160 light sensor

Claims (17)

A light source for irradiating a laser beam toward a coating film applied to a region on the substrate;
A light sensor for acquiring optical interference data due to interference between a reference light generated when the laser light is reflected by the surface of the coating film and a measurement light scattered by the laser light through the coating film;
A processor for deriving the thickness of the coating film corresponding to the one area based on the light interference data. The processor is
Acquiring a cross-sectional image showing a cross-section in the depth direction of the coating film based on the light interference data;
The substrate inspection apparatus according to claim 1, wherein the thickness of the coating film is determined based on boundaries on the cross-sectional image.   The substrate inspection apparatus according to claim 1, further comprising a moving unit that moves the light source. The processor is
The reflectance of the surface of the coating film is derived based on the light amount of the reference light,
The substrate inspection apparatus according to claim 3, wherein the light source is moved by controlling the moving unit when the reflectance is less than the already defined reflectance. The light source emits the laser light toward the coating film along a first direction,
The substrate inspection apparatus according to claim 1, wherein the light sensor captures the reference light and measurement light traveling in a direction opposite to the first direction to acquire the light interference data.   The substrate inspection apparatus according to claim 1, wherein the light source is disposed such that the laser light is directly irradiated to the surface of the coating film without transmitting a medium other than air. The reflectance of the surface of the coating film to the laser light is determined by the fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film,
The substrate inspection apparatus according to claim 1, wherein the fluorescent dye mixture ratio is set to a value that causes the reflectance to exceed a preset reference value.   The coating film is formed of at least one material selected from acrylic, urethane, polyurethane, silicon, epoxy, UV (Ultra Violet) cured material and IR (Infra Red) cured material. The substrate inspection apparatus according to Item 1.   The substrate inspection apparatus according to claim 1, wherein a surface of the coating film is formed in a curved surface. Irradiating a laser beam toward a coating film applied to a region on the substrate;
Obtaining optical interference data due to interference between a reference light generated by the laser light reflecting off the surface of the coating film and a measurement light scattered by the laser light transmitting through the coating film;
Deriving the thickness of the coating film corresponding to the one area based on the light interference data;
Board inspection method including: The step of deriving the thickness of the coating film is
Acquiring a cross-sectional image showing a cross-section in the depth direction of the coating film based on the light interference data;
The substrate inspection method according to claim 10, further comprising: determining the thickness of the coating film based on boundaries on the cross-sectional image. Deriving the reflectance of the surface of the coating film based on the light amount of the reference light;
The substrate inspection method according to claim 10, further comprising: moving the light source if the reflectance is less than the previously defined reflectance.   The substrate inspection according to claim 10, wherein the laser light is irradiated toward the one region along a first direction, and the reference light and the measurement light travel in a direction opposite to the first direction. Method.   The substrate inspection method according to claim 10, wherein the laser light is directly irradiated to the surface of the coating film without transmitting a medium other than air. The reflectance of the surface of the coating film to the laser light is determined by the fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film,
The substrate inspection method according to claim 10, wherein the fluorescent dye mixture ratio is set to a value that causes the reflectance to exceed a preset reference value.   The substrate inspection method according to claim 10, wherein the coating film is formed of at least one material selected from acrylic, urethane, polyurethane, silicon, epoxy, UV curing material and IR curing material. . The substrate inspection method according to claim 10, wherein the surface of the coating film is formed in a curved surface.