KR102195240B1 - Apparatus for inspecting substrate and method thereof - Google Patents

Abstract

The present disclosure proposes a substrate inspection apparatus. A substrate inspection apparatus according to the present disclosure includes: a light source for irradiating laser light toward a coating film applied to a region on a substrate; A light detector for acquiring optical interference data according to interference between the reference light generated by reflecting the laser light by the surface of the coating layer and the measurement light scattered by the laser light passing through the coating layer; And a processor for deriving a thickness of the coating film corresponding to the one region based on the optical interference data.

Description

Substrate inspection apparatus and substrate inspection method {APPARATUS FOR INSPECTING SUBSTRATE AND METHOD THEREOF}

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

In the processing process of the substrate, a substrate may be coated to protect elements on the substrate. This coating can be referred to as a conformal coating. A thickness test of the conformal coating film may be performed to check whether the coating film formed by the coating is evenly applied to a predetermined thickness.

In order to inspect the thickness of the coating film, a two-dimensional fluorescence photographic inspection may be performed. However, the 2D imaging inspection is only possible to qualitatively check the thickness of the coating film, and it may not be possible to measure the exact thickness value of the coating film. In addition, the 2D imaging inspection may be difficult to measure the thickness when the coating film is thin (eg, about 30 μm).

For inspection of the thickness of the coating film, a method using OCT (Optical Coherence Tomography) may be used. However, when performing a thickness test of the coating film using OCT, saturation of light may occur due to reflection by a reference mirror, which may cause an error in thickness measurement. In addition, due to components such as a reference mirror of the OCT, a window glass, or a beam splitter, miniaturization of the OCT may be difficult.

US Patent Application Publication No. 2008/062429 (2008.03.13.) U.S. Patent No. 6,507,747 (2003.01.14.) US Patent Application Publication No. 2015/226537 (2015.08.13.) International Application Publication No. 2014/192734 (2014.12.04.)

The present disclosure is to solve the above-described problem, and provides a technique for measuring the thickness of a coating film of a substrate.

As an aspect of the present disclosure, a substrate inspection apparatus may be proposed. A substrate inspection apparatus according to an aspect of the present disclosure includes: a light source for irradiating laser light toward a coating film applied to a region on a substrate; A light detector for acquiring optical interference data according to interference between the reference light generated by reflecting the laser light by the surface of the coating layer and the measurement light scattered by the laser light passing through the coating layer; And a processor for deriving a thickness of the coating film corresponding to the one region based on the optical interference data.

In an embodiment, the processor may acquire a cross-sectional image representing a cross section in a depth direction of the coating layer based on the optical interference data, and determine the thickness of the coating layer based on a boundary line on the cross-sectional image.

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

In an embodiment, the processor may derive a reflectance of the surface of the coating layer based on the amount of light of the reference light, and when the reflectance is less than a predefined reflectance, the processor may control the moving unit to move the light source.

In one embodiment, a light source irradiates the laser light toward the coating film along a first direction, and the light detector captures the reference light and measurement light traveling in a direction opposite to the first direction to obtain the optical interference data can do.

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

In one embodiment, the reflectance of the surface of the coating film with respect to the 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 a value such that the reflectance exceeds a preset reference value. Can be set.

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

In one embodiment, the surface of the coating film may be formed in a curved surface.

As an aspect of the present disclosure, a substrate inspection method may be proposed. A method for inspecting a substrate according to an aspect of the present disclosure includes: irradiating a laser light toward a coating film applied to an area on a substrate; Acquiring optical interference data according to interference between the reference light generated by reflecting the laser light by the surface of the coating film and the measurement light scattered by the laser light passing through the coating film; And deriving a thickness of the coating film corresponding to the one region based on the optical interference data.

In one embodiment, the step of deriving the thickness of the coating layer may include: acquiring a cross-sectional image representing a cross section of the coating layer in a depth direction based on the optical interference data; And determining the thickness of the coating film based on the boundary line on the cross-sectional image.

In an embodiment, deriving a reflectance of the surface of the coating film based on the amount of light of the reference light; And moving the light source when the reflectance is less than a predefined reflectance.

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

In one embodiment, laser light may be directly irradiated onto the surface of the coating film without passing through a medium other than air.

In one embodiment, the reflectance of the surface of the coating film with respect to the 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 a value such that the reflectance exceeds a preset reference value. Can be set.

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

In one embodiment, the surface of the coating film may be formed in a curved surface.

According to various embodiments of the present disclosure, the substrate inspection apparatus can accurately measure the thickness even when the coating film is thin to a predetermined thickness (eg, about 30 μm) or less.

According to various embodiments of the present disclosure, the substrate inspection apparatus may reduce a measurement error due to light saturation by measuring the thickness of the coating layer without components such as a reference mirror.

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

1 is a view showing an embodiment of a process of operating a substrate inspection apparatus according to an embodiment.
2 is a diagram illustrating an embodiment of a process of operating the substrate inspection apparatus according to the present disclosure.
3 is a diagram illustrating a block diagram of an inspection apparatus 10 according to various embodiments of the present disclosure.
4 is a diagram illustrating a cross-sectional image and a boundary line appearing on the cross-sectional image according to an embodiment of the present disclosure.
5 is a view showing a depth direction measurement range of the inspection apparatus 10 according to an embodiment of the present disclosure.
6 is a diagram illustrating a process in which the processor 110 derives a thickness of a coating film based on a plurality of boundary lines according to an embodiment of the present disclosure.
7 is a diagram illustrating a process in which the processor 110 excludes some boundary lines according to a predetermined criterion according to an embodiment of the present disclosure.
8 is a diagram illustrating a process of adjusting a thickness measurement area based on a reflectance of a coating film according to an embodiment of the present disclosure.
9 is a diagram illustrating a process of sampling an area to be measured by the OCT part 170 through a photographic inspection using a fluorescent dye according to an exemplary embodiment of the present disclosure.
10 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples a region for thickness measurement by the OCT part 170 according to an element arrangement according to an exemplary embodiment of the present disclosure.
11 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples a region for thickness measurement by the OCT part 170 according to an exemplary embodiment of the present disclosure.
12 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples an area adjacent to an area in which thickness measurement is to be performed by the OCT part 170 according to an embodiment of the present disclosure.
13 is a diagram showing an embodiment of a substrate inspection method that can be performed by the inspection apparatus 10 according to the present disclosure.

The various embodiments described in this document are exemplified for the purpose of clearly describing the technical idea of the present disclosure, and are not intended to be limited to specific embodiments. The technical idea of the present disclosure includes various modifications, equivalents, alternatives, and embodiments selectively combined from all or part of each embodiment described in this document. In addition, the scope of the technical idea of the present disclosure is not limited to various embodiments or detailed descriptions thereof presented below.

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

Expressions such as "include", "may include", "have", "have", "have", "may have", etc. used in this document, are the target features (eg: Function, operation, or component, etc.) is present, and the presence of other additional features is not excluded. That is, such expressions should be understood as open-ended terms that imply the possibility of including other embodiments.

As used herein, expressions of the singular form may include the meaning of the plural unless the context indicates otherwise, and this applies to the expression of the singular form in the claims as well.

Expressions such as "first", "second", or "first" and "second" used in this document distinguish one object from another in referring to a plurality of homogeneous objects unless the context indicates otherwise. It is used to do so, and does not limit the order or importance of the objects.

"A, B, and C", "A, B, or C", "A, B, and/or C" or "at least one of A, B, and C", "A, B" as used herein , Or at least one of C", "at least one of A, B, and/or C" may mean each listed item or all possible combinations of the listed items. For example, "at least one of A or B" may refer to all of (1) at least one A, (2) at least one B, (3) at least one A, and at least one B.

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

The expression "based on" as used in this document is used to describe one or more factors that influence the act or action of a decision or judgment, which is described in the phrase or sentence in which the expression is included, and this expression is It does not exclude additional factors that influence the action or action of a decision or judgment.

As used in this document, the expression that a certain component (eg, a first component) is “connected” or “connected” to another component (eg, a second component) means that the certain component is In addition to being directly connected or connected to another component, it may mean that the device is connected or connected via a new other component (eg, a third component).

The expression "configured to" as used in this document is, depending on the context, "configured to", "having the ability to ...", "modified to", "made to", "to do It may have a meaning such as "can be". The expression is not limited to the meaning of "specially designed for hardware", and for example, a processor configured to perform a specific operation is a generic-purpose processor capable of performing a specific operation by executing software Can mean

In order to describe various embodiments of the present disclosure, a Cartesian coordinate system having an X axis, a Y axis, and a Z axis that are orthogonal to each other may be defined. As used in this document, expressions such as "X-axis direction", "Y-axis direction", and "Z-axis direction" of a Cartesian coordinate system are both sides of the Cartesian coordinate system where each axis extends unless specifically defined otherwise in the description. It can mean direction. In addition, the + sign in front of each axis direction may mean a positive direction, which is one of both directions extending in the corresponding axis direction, and a-sign in front of each axis direction is a sign that extends in the corresponding axis direction. It may mean a negative direction, which is the other of both directions.

In the present disclosure, a substrate is a plate or a container on which a device such as a semiconductor chip is mounted, and may serve as a connection path for electrical signals between the device and the device. The substrate may be used for fabricating an integrated circuit or the like, and may be made of a material such as silicon. For example, the substrate may be a printed circuit board (PCB), and may be referred to as a wafer or the like according to embodiments.

In the present disclosure, the coating film may be a thin film generated on the substrate by coating for protecting the devices on the substrate. If the coating film is thick, the film may be cracked and may affect the operation of the substrate. Therefore, it is necessary to prevent the coating film from being cracked by applying the coating film relatively thinly and evenly. In one embodiment, the coating film may be formed of at least one material selected from acrylic, urethane, polyurethane, silicone, epoxy, UV (Ultra Violet) curing material, and IR (Infra Red) curing material. The coating film formed of the above-described material may have a higher reflectance of the surface of the coating film and/or a back scattering ratio of the coating film, which will be described later, compared to a coating film that does not.

In the present disclosure, OCT (Optical Coherence Tomography) may be an imaging technique for capturing an image in an object by using an interference phenomenon of light. An image representing the interior of the object in the depth direction from the surface of the object may be obtained using OCT. In general, it is based on an interferometer, and the depth direction resolution of the object may vary depending on the wavelength of light to be used. Compared to another optical technology, a confocal microscope, an image can be acquired by penetrating deeper into the object.

Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings and description of the drawings, the same reference numerals may be assigned to identical or substantially equivalent components. In addition, in the following description of various embodiments, overlapping descriptions of the same or corresponding elements may be omitted, but this does not mean that the corresponding elements are not included in the exemplary embodiments.

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 may further include a light source 150, a light detector 160, a reference mirror 172 and/or a beam splitter 171.

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

Specifically, the light source 150 may irradiate laser light. In one embodiment, the light source 150 may directly irradiate the laser light toward the beam splitter 171. In one embodiment, the light source 150 transmits the laser light to the convex lens 173 through the optical fiber 174, and the laser light passing through the convex lens 173 may be transmitted toward the beam splitter 171. have.

The beam splitter 171 adjusts the optical path so as to pass a part of the laser light transmitted from the light source 150 toward the coating film of the substrate 2, and reflects another part of the laser light toward the reference mirror 172. Can be adjusted.

A portion of the laser light whose optical path is adjusted to face the coating film of the substrate 2 may be reflected by the coating film of the substrate 2. This reflected light can be referred to as measurement light. The measurement light travels toward the beam splitter 171 and may be transmitted to the light detector 160 by the beam splitter 171. Another part of the laser light whose optical path is adjusted to face the reference mirror 172 may be reflected by the reference mirror 172. This reflected light can be referred to as a reference light. The reference light may pass through the beam splitter 171 and be transmitted to the light detector 160.

The light detector 160 may acquire optical interference data by capturing interference light formed by interfering with the measurement light and the reference light. In the present disclosure, in the measurement of an object according to the OCT method, the optical interference data is obtained from interference light generated by interfering with the measurement light reflected from the object and the reference light reflected from the reference mirror, etc. It can mean the data that becomes. An interference phenomenon may occur depending on the difference in characteristics (optical path, wavelength, etc.) between the measurement light and the reference light, and the optical detector may capture the interference phenomenon to obtain optical interference data. Also, based on the optical interference data, a cross-sectional image indicating a cross-section in the depth direction of the coating film may be generated. Optical interference data may also be referred to as an interference signal. A substrate inspection apparatus using a reference mirror can derive the thickness of the coating film applied to the substrate 2 by using optical interference data by reference light and measurement light.

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

The inspection apparatus 10 according to various embodiments of the present disclosure may measure the thickness of the coating film of the substrate 2 using OCT. In one embodiment, the inspection apparatus 10 may measure the thickness of the coating layer by using the reflected light on the surface of the coating layer without using the aforementioned reference mirror or a predetermined window glass.

Specifically, the inspection apparatus 10 according to the present disclosure may include a light source 150 and/or a light detector 160 without the reference mirror 172 or the beam splitter 171. The light source 150 of the inspection apparatus 10 may irradiate laser light toward the coating film of the substrate 2. In this case, laser light may be irradiated 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 may be referred to as 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 directly irradiate the laser light, but the laser light may be irradiated through the optical fiber 174 and/or the convex lens 173.

In the present disclosure, the x-axis and y-axis may be axes included in a plane corresponding to the surface of the substrate 2, respectively. The x-axis and y-axis may be orthogonal to each other on the corresponding plane. Further, each of the x-axis and y-axis may be orthogonal to the z-axis described above.

The laser light may be reflected off the surface of the coating film. Specifically, the laser light may be reflected from the illustrated first surface. In addition, the laser light may pass through the coating film and be scattered back. Here, the reflected light reflected from the surface of the coating film may serve as the above-described reference light, and the scattered light may serve as the above-described measurement light. That is, in this case, the reference light may be generated by reflecting the laser light by the surface of the coating layer, and the measurement light may be generated by scattering the laser light through the coating layer. Reflected light (ie, reference light) and scattered light (ie, measurement light) may proceed in a direction opposite to the above-described first direction to form interference light. That is, the irradiated laser light and the above-described interference light (that is, reflected light and scattered light) may proceed coaxially, but may proceed in opposite directions. The light detector may capture interfering light (ie, reflected light and scattered light) traveling in a direction opposite to the first direction. The light detector 160 may acquire optical interference data from the captured interference light. The processor 110 may obtain the optical interference data from the photodetector 160 and generate a cross-sectional image based on the data to derive the thickness of the coating film applied to the corresponding region of the substrate 2.

As described above, when the inspection apparatus 10 according to the present disclosure measures the coating film thickness, the above-described reflected light and scattered light may each serve as a reference light and a measurement light of a substrate inspection apparatus using the aforementioned reference mirror. . In other words, the coating film itself of the substrate 2 may serve as the above-described reference mirror 172 according to its reflectivity. In one embodiment, the inspection apparatus 10 may not arrange an additional component such as a window glass on the coating film of the substrate 2. Since the inspection apparatus 10 according to the present disclosure forms interference light by using the reflected light reflected by the surface of the coating film as a reference light, additional elements such as window glass may not be required.

3 is a diagram illustrating a block diagram of an inspection apparatus 10 according to various embodiments of the present disclosure. As described above, the inspection apparatus 10 may include a light source 150 and a light detector 160, and may further include a processor 110 and a memory 120. In one embodiment, at least one of these components of the testing device 10 may be omitted, or another component may be added to the testing device 10. Additionally or alternatively, some components may be integrated and implemented, or may be implemented as singular or plural entities. At least some of the components inside and outside the inspection device 10 are connected to each other through a bus, general purpose input/output (GPIO), serial peripheral interface (SPI), mobile industry processor interface (MIPI), etc. , Data and/or signals can be exchanged.

As described above, the light source 150 may irradiate laser light toward the coating film of the substrate 2. The arrangement of the light source 150 and the position relative to the substrate may be variously configured. In one embodiment, the light source 150 may be disposed on the z-axis described above. In one embodiment, the light source 150 may use a laser capable of varying a wavelength within a short time, and optical interference data corresponding to different wavelengths may be obtained using this. In one embodiment, the inspection device 10 may include a plurality of light sources 150.

The light detector 160 may capture interference light generated from the coating film by laser light. Specifically, the light detector 160 detects the reflected light (i.e., reference light) reflected from the surface of the coating film and the interference light generated by the back-scattered scattered light (i.e., measurement light) after being transmitted to a predetermined depth from the coating film. You can capture it. By using the optical interference data obtained by capturing such interference light, a cross-sectional image based on the surface of the coating layer may be generated. In one embodiment, the light detector 160 may be disposed on the z-axis described above. In one embodiment, the light detector 160 may not be disposed on the z-axis, in which case certain additional components may be adjusted to direct the optical paths of the reflected and scattered light to the light detector 160. In one embodiment, the inspection device 10 may include a plurality of light detectors 160. The light detector 160 may be implemented by a CCD or CMOS. Depending on the embodiment, the light source 150 and the light detector 160 may be collectively referred to as the OCT part 170 of the inspection apparatus 10.

The processor 110 may control at least one component of the test apparatus 10 connected to the processor 110 by driving software (eg, a program). In addition, the processor 110 may perform various operations related to the present disclosure, processing, data generation, and processing. In addition, the processor 110 may load data or the like from the memory 120 or may store the data in the memory 120.

The processor 110 may obtain optical interference data according to the above-described interference light from the optical sensor 160. The processor 110 may derive the thickness of the coating film applied to a region of the substrate 2 to which the laser light has been irradiated, based on one or more optical interference data. The process of deriving the thickness of the coating film from the optical interference data will be described later.

The memory 120 may store various types of data. Data stored in the memory 120 is data acquired, processed, or used by at least one component of the test apparatus 10, and may include software (eg, a program). The memory 120 may include volatile and/or nonvolatile memory. The memory 120 may store one or more optical interference data obtained from the light detector 160. In addition, the memory 120 may store device arrangement information, device 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 various functions are applied so that an operating system, an application, and/or an application for controlling the resources of the testing device 10 can utilize the resources of the testing device 10. It may include middleware and the like provided to.

In one embodiment, the testing device 10 may further include a communication interface (not shown). The communication interface may perform wireless or wired communication between the test device 10 and a server, or between the test device 10 and another external electronic device. For example, the communication interface is LTE (long-term evolution), LTE-A (LTE Advance), CDMA (code division multiple access), WCDMA (wideband CDMA), WiBro (Wireless Broadband), WiFi (wireless fidelity), Bluetooth Wireless communication may be performed according to a method such as (Bluetooth), near field communication (NFC), global positioning system (GPS), or global navigation satellite system (GNSS). For example, the communication interface may perform wired communication according to a method such as universal serial bus (USB), high definition multimedia interface (HDMI), recommended standard 232 (RS-232), or plain old telephone service (POTS).

In one embodiment, the processor 110 may obtain information from the server by controlling the communication interface. Information obtained from the server may be stored in the memory 120. In an embodiment, the information obtained from the server may include device arrangement information, device density information, electrode location information, and the like to be described later.

In one embodiment, the inspection device 10 may further include an additional light source 130 and an additional light detector 140 to be described later. The additional light source 130 and the additional light detector 140 may be used to obtain a two-dimensional image of the coating layer of the substrate 2 and measure the thickness of the coating layer.

In one embodiment, the inspection device 10 may further include a moving unit to be described later. The moving unit may move the light source 150 to the OCT part 170 along the x, y, and z axes described above.

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

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

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

Various embodiments of the inspection apparatus 10 according to the present disclosure may be combined with each other. Each of the embodiments may be combined according to the number of cases, and embodiments of the test apparatus 10 made by combining are also within the scope of the present disclosure. In addition, internal/external components of the inspection apparatus 10 according to the present disclosure described above may be added, changed, replaced or deleted according to embodiments. In addition, internal/external components of the above-described inspection apparatus 10 may be implemented as hardware components.

4 is a diagram illustrating a cross-sectional image and a boundary line appearing on the cross-sectional image according to an embodiment of the present disclosure. As described above, the processor 110 may derive the thickness of the coating film applied to a predetermined area of the substrate 2 from the acquired optical interference data. The processor 110 may generate a cross-sectional image from the optical interference data and derive the thickness of the coating layer by using information on the cross-sectional image.

In the present disclosure, the cross-sectional image may mean that a cross-section in the depth direction of the object (coating film) is represented as a two-dimensional image in measuring an object according to the OCT method. The cross-sectional image may be generated based on the measured optical interference data. The cross-sectional image may have boundary lines (border patterns) corresponding to the interface between the air and the coating film and the coating film and the substrate.

Specifically, the processor 110 may obtain a cross-sectional image as shown through the optical interference data captured by the light sensor 160. The cross-sectional image may be an image showing a cross section of the substrate 2 and the coating film in the -z axis direction, that is, in the depth direction. That is, the cross-sectional image may represent the interior of the coating layer and the substrate, which is transmitted in the depth direction from the surface of the coating layer.

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

Specifically, in the case of a substrate inspection apparatus using a reference mirror, a cross-sectional image 4010 based on a reference mirror surface may be obtained. The substrate inspection apparatus may determine a boundary line representing the interface between the air and the coating film from the illustrated cross-sectional image 4010. In addition, the substrate inspection apparatus may determine a boundary line indicating an interface between the coating layer and the substrate 2 on which the coating layer is applied from the cross-sectional image 4010. The substrate inspection apparatus may derive a vertical distance between the two determined boundary lines on the cross-sectional image 4010 and determine the vertical distance as the thickness of the coating film.

Meanwhile, when the substrate inspection apparatus (eg, the inspection apparatus 10) according to the present disclosure is used, a cross-sectional image 4020 based on the surface of the coating layer may be obtained. The cross-sectional image 4020 may have one or more boundary lines 4040. One of the boundary lines 4040 may be a boundary line corresponding to an interface between the coating film and the substrate 2 to which the coating film is applied to the electrode. The processor 110 of the inspection apparatus 10 may derive the thickness of the coating film by using the gap between the boundary line 4040 and the upper side 4030 of the cross-sectional image 4020.

In the case of the inspection apparatus 10 according to the present disclosure, the processor 110 may detect a boundary line 4040 indicating an interface between the coating film and the substrate 2 on which the coating film is applied. In an embodiment, the processor 110 may determine a boundary line first appearing in the depth direction from the upper side of the cross-sectional image 4020 as the corresponding boundary line 4040. In addition, in the case of the inspection device 10, since optical interference data is generated using the reflected light reflected from the surface of the coating film, the cross-sectional image is from the surface of the coating film as the origin, in the -z-axis direction, that is, in the depth direction. The cross section of can be shown. Accordingly, the upper side 4030 of the cross-sectional image 4020 obtained by the inspection device 10 may correspond to the surface of the coating film. The processor 110 may derive a vertical distance between the detected boundary line 4040 and the upper side 4030 of the cross-sectional image 4020 and determine the vertical distance as the thickness of the coating film. In an embodiment, the processor 110 may determine the derived value as the thickness of the coating layer by applying a predetermined scaling factor to the derived vertical distance.

In one embodiment, in the measurement of the coating film thickness of the substrate 2 using OCT, laser light, reflected light, scattered light and/or interference light may be moved through vacuum or other medium instead of air. That is, the light source 150 may be arranged so that the laser light does not pass through a medium other than air and is directly irradiated to the surface of the coating film.

5 is a view showing a depth direction measurement range 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 obtained by the substrate inspection apparatus using the above-described reference mirror. The cross-sectional image 5010 may have a boundary line indicating an interface between the air and the coating film and a boundary line indicating an interface between the coating film and the substrate PCB. In addition, the illustrated cross-sectional image 5020 may be a cross-sectional image obtained by the substrate inspection apparatus (eg, inspection apparatus 10) according to the present disclosure. The cross-sectional image 5020 may have a boundary line indicating an interface between the coating film and the substrate PCB.

In one embodiment, the cross-sectional image 5010 may be larger than the cross-sectional image 5020. That is, the cross-sectional image 5010 may have a larger amount of data than the cross-sectional image 5020. In the case of measurement by the inspection device 10, unlike the case of using a reference mirror, since 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 from the surface of the coating film. This may be because it is limited to what starts.

In the illustrated cross-sectional view 5030, in the case of a substrate inspection apparatus using a reference mirror, a measurement range 5040 taking into account all height differences due to elements mounted on the substrate 2 may be required in order to obtain a meaningful measurement result. However, in the case of measuring the thickness of the coating film using the inspection device 10, it is possible to obtain a meaningful thickness measurement result only with the measurement range 5050 of the maximum expected thickness of the coating film. In other words, the inspection apparatus 10 can reduce the measurement range in the depth direction required for measuring the thickness of the coating film, thereby reducing the computational capacity required for processing the measurement result and the memory required for storage.

In addition, in the case of measuring the coating film thickness using the inspection device 10, since the reference mirror is not used, the possibility of occurrence of measurement errors due to saturation of 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 may be saturated. When saturation is reached, an interference signal appears irrespective of the interference signal generated by the measurement object, which may interfere with accurate measurement. This saturation phenomenon is more likely to occur when a reference mirror with high reflectivity is used. The inspection apparatus 10 can reduce measurement errors due to saturation by excluding the use of the reference mirror.

6 is a diagram illustrating a process in which the processor 110 derives a thickness of a coating film based on a plurality of boundary lines according to an embodiment of the present disclosure. In an embodiment, the inspection apparatus 10 may derive the thickness of the coating film corresponding to the corresponding region by using a plurality of cross-sectional images previously acquired for a predetermined region stored in the memory. To this end, a plurality of cross-sectional images may be obtained in advance through a plurality of measurements and stored in a memory. Accordingly, the inspection apparatus 10 can derive the thickness of the coating film while minimizing the effect of noise.

As described above, the processor 110 may acquire one cross-sectional image based on 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 may represent a cross section of the coating film of the substrate 2 in the -z axis, that is, in the depth direction. Each of the plurality of cross-sectional images 6010 may have a boundary line 6020 indicating an interface between the coating film and the substrate 2.

The processor 110 may acquire a plurality of boundary lines 6020 from each of the cross-sectional images 6010. The processor 110 may determine one of the plurality of boundary lines 6020 as a boundary line 6030 indicating a boundary between the coating film and a region of the substrate 2 on which the coating film is applied. The processor 110 may derive the thickness of the coating film according to the above-described method based on the determined boundary line.

In one embodiment, the processor 110 derives an average value, a median value, or a mode of the plurality of boundary lines 6020, and calculates a boundary line according to the average value, a median value, or a mode, the coating film and the substrate 2 ) Can be determined as a boundary line 6030 indicating the boundary between the two. Based on the determined boundary line 6030, the processor may derive the thickness of the coating film corresponding to an area of the boundary surface.

In the present disclosure, the average value may be a value obtained by adding the values of all samples and then dividing the total number of samples. In the present disclosure, the median value may mean a value at the center of the values of all samples. The values of the samples can be sorted from a small number to a large number, and when the number of samples is odd, the centered value is the median, and when the number of samples is even, the average value of the two centered values can be used as the median. . In the present disclosure, the mode may mean a value that appears with the highest frequency among values of samples. In particular, in the present disclosure, the average value, the median value, or the mode value of the boundary lines may mean the average value, the median value, or the mode value of the position coordinates of the corresponding boundary lines in the cross-sectional image. That is, when a cross-sectional image is viewed as a plane of x and y axes, each point of a boundary line in the cross-sectional image may have x and y coordinate values. In the plurality of cross-sectional images 6010, the average, median, or mode values of the x and y coordinate values each of the plurality of boundary lines 6020 have can be derived, and the boundary line according to the derived coordinate values is the above-described average value, median value or It may be a boundary line 6030 according to the mode.

7 is a diagram illustrating a process in which the processor 110 excludes some boundary lines according to a predetermined criterion according to an embodiment of the present disclosure. In one embodiment, the processor 110 derives an average value of the plurality of boundary lines 6020 described above, excludes a boundary line deviating from the derived average value by a predetermined ratio or more, and then determines a boundary line that will be the basis for deriving the coating film thickness only with the remaining boundary lines. You can decide. This may be for performing a coating film thickness measurement excluding a value due to an obvious measurement error by excluding a boundary line significantly out of a certain range among the plurality of boundary lines 6020. Through this, more accurate thickness measurement may be possible.

Specifically, the processor 110 may derive a first average value for the plurality of boundary lines 6020. The process of deriving the average value of the boundary lines may be performed as described above. The processor 110 may exclude the boundary line 7030 in which the derived first average value is deviated by more than a predefined ratio among the plurality of boundary lines 6020. That is, when the range according to the predetermined ratio of the derived first average value is an area between the illustrated dotted lines 7020, the boundary lines 7010 included in the area are maintained, and boundary lines 7030 outside the area are maintained. ) May be excluded from further processing. The processor 110 may derive a second average value of the remaining boundary lines 7010 excluding the boundary line 7030 deviating from a predetermined ratio or more. The process of deriving the average value of the boundary lines may be performed as described above. The processor 110 may determine a boundary line according to the derived second average value as a boundary line indicating a boundary surface between the coating film and the substrate 2. Based on the determined boundary line, the processor may derive the thickness of the coating film corresponding to a region of the boundary surface.

In one embodiment, the processor 110 may perform an operation of excluding a predetermined boundary line, as described above, using a median value or a mode value other than an average value. For example, the processor 110 derives a first median value of the plurality of border lines 6020, excludes a border line that deviates from the first median value by a predetermined ratio, and calculates a border line according to the second median value of the remaining border lines, based on derivation of the coating film thickness. Can be determined by the boundary line. The same is true for the mode. In one embodiment, an average value, a median value, and a mode value may be used in combination with each other.

8 is a diagram illustrating a process of adjusting a thickness measurement area based on a 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 greater than or equal to a predetermined reference value, the inspection apparatus 10 that does not use a reference mirror may be used. The predetermined reference value may be a minimum reflectance required for the surface of the coating film to perform 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 may mean a ratio between the reflected light generated by reflection from the surface of the coating film (ie, reference light) and laser light irradiated to the coating film.

In one embodiment, the inspection apparatus 10 derives the reflectance of the coating film based on the amount of reflected light (ie, reference light) by the surface of the coating film, and moves the light source 150 to the OCT part 170 according to the reflectance. Thickness measurement can be performed. Since the inspection apparatus 10 that does not use a reference mirror acquires optical interference data based on the reflectance of the coating film, it is possible to obtain a more meaningful measurement result by finely adjusting the measurement target point according to the reflectance of the coating film.

Specifically, the light detector 160 may measure the amount of light of the reference light when capturing interference light due to the above-described reflected light (ie, reference light) and scattered light (ie, measurement light). The processor 110 may derive a reflectance in the z-axis direction in a corresponding region of the surface of the coating layer based on the measured amount of reference light by the coating layer. The reflectance in the z-axis direction may mean a ratio in which the irradiated laser light is reflected in the +z-axis direction.

When the derived reflectance is greater than or equal to a predefined reflectance, the processor 110 determines that one or more optical interference data formed by the reference light is valid optical interference data, and derives the thickness of the coating layer using the optical interference data. can do. The predefined reflectance is a minimum reflectance required for the coating film to function as a reference mirror, and may be a predetermined reference value described above.

When the derived reflectance is less than a predefined reflectance, the processor 110 may configure the light source 150 to the OCT part 170 so that the laser light is irradiated toward another area 8020 adjacent to the initial measurement target area 8010. Can be moved. In one embodiment, the inspection device 10 may further include a moving unit. The moving unit may 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 axes included in a plane corresponding to the surface of the substrate 2, respectively, may be perpendicular to each other on the plane, and the z-axis may be an axis corresponding to a normal direction of the substrate. Each of the x-axis and y-axis may be orthogonal to the z-axis described above. The processor 110 controls the moving unit so that the laser light is irradiated toward the other area 8020 adjacent to the initial measurement target area 8010, so that the light source 150 to the OCT part 170 are x-axis and/or y It can be moved in the axial direction.

In an embodiment, the processor 110 may adjust the position of the light source 150 to the OCT part 170 on the z-axis by controlling the moving unit based on the obtained resolution of one or more captured interfering lights. That is, the moving unit may move the light source 150 to 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 caused by the above-described reflected light (i.e., reference light) and scattered light (i.e., measurement light), whether or not the interference occurs easily will be determined according to the phase difference according to the moving path of laser light, reflected light, and scattered light I can. The processor 110 may control the moving unit to adjust the positions of the light source 150 to the OCT part 170 on the z-axis, thereby performing adjustment to obtain an interference signal of more clear interference light.

In the illustrated measurement area adjustment process 810, the OCT part 170 may be moved by the moving unit. Accordingly, the area to be measured by the OCT part 170 or the area 8010 to which the laser light is irradiated may be moved in the x-axis or y-axis. This may be due to the fact that the reflectance of the coating film in the existing region 8010 did not meet a predetermined standard. The new irradiation area 8020 may be determined as an adjacent area in which the measured thickness of the coating film corresponding to the new irradiation area 8020 may be considered or approximated as the thickness of the coating film corresponding to the existing area 8010. A region adjacent to one region will be described later. In addition, unlike the existing area 8010, the new irradiation area 8020 may be determined as an area in which the +z-axis reflectance of the reference light is greater than or equal to a predetermined reference. In an embodiment, the new irradiation area 8020 may be determined as an area having a +z-axis reflectance of the reference light higher than that of the existing area 8010 by a certain ratio or more.

When this process is viewed from a cross section (820), the light source 150 is moved by the moving part, so that the 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 may have a reflectance of the coating film in the +z-axis direction less than a predetermined reference. This may be because the surface of the coating film of the conventional irradiation area 8010 is not parallel to the normal line of the substrate, but is inclined at a certain angle or more. Further, based on the resolution of the captured interference light, the moving unit may move the light source 150 to the OCT part 170 in the z-axis direction.

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

In one embodiment, the reflectance of the surface of the coating layer may be determined by the mixing ratio of the fluorescent dye of the coating layer. In one embodiment, the coating layer in which the fluorescent dye is mixed may have a higher reflectance of the surface of the coating layer compared to a substrate that does not. The higher the mixing ratio of the fluorescent dye of the coating film is, the higher the reflectivity of the surface of the coating film may be. That is, when a coating film in which a fluorescent dye is mixed is used, the reflectance of the surface of the coating film is increased, and accordingly, thickness measurement by the inspection apparatus 10 not using a reference mirror can be easily performed. In an embodiment, the mixing ratio of the fluorescent dye of the coating film may be set to a value such that the reflectance of the surface of the coating film exceeds a preset reference value. Depending on the embodiment, this reference value may be a minimum reflectance required for the surface of the coating film to perform the role of the reference mirror 172, or may be a value arbitrarily set according to the intention of the practitioner.

In addition, in one embodiment, the back scattering rate of the coating layer may also be determined by the fluorescent dye mixing rate of the coating layer. In one embodiment, the coating layer mixed with the fluorescent dye may have a higher back scattering rate of the coating layer than the substrate without the fluorescent dye. In the thickness measurement by the inspection apparatus 10 that does not use the reference mirror of the present disclosure, the back scattering rate of the coating film is the ratio between the above-described scattered light (i.e., measurement light) back-scattered and the laser light irradiated to the coating film. It can mean. The higher the mixing ratio of the fluorescent dye in the coating film, the higher the backscattering ratio of the coating film may be. That is, when a coating film in which a fluorescent dye is mixed is used, the back scattering rate of the coating film is increased, and accordingly, thickness measurement by the inspection device 10 not using a reference mirror can be easily performed. In one embodiment, the mixing ratio of the fluorescent dye of the coating film may be set to a value such that the back scattering ratio of the coating film exceeds a preset reference value.

In one embodiment, the surface of the coating film may be formed in a curved surface. In one embodiment, the surface of the coating film may be formed as a convex curved surface, a concave curved surface, or a curved surface having an arbitrary shape with respect to the substrate. In one embodiment, when the surface of the coating film is curved, the thickness measurement by the inspection apparatus 10 that does not use a reference mirror can be easily performed compared to when the surface of the coating film is flat.

9 is a diagram illustrating a process of sampling an area to be measured by the OCT part 170 through a photographic inspection using a fluorescent dye according to an exemplary 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 criterion based on the inspection result, and uses the OCT for the derived area. Measurement of the thickness of the coating film can be performed.

First, the inspection apparatus 10 may perform a photographic inspection using a fluorescent dye on the substrate 2. The photographic examination may be a fluorescence photographic examination. For this inspection, a fluorescent dye may be mixed in advance in the coating film applied on the substrate 2. According to an embodiment, the inspection apparatus 10 according to the present disclosure may further include an additional light source 130 and/or an additional light detector 140. The additional light source 130 of the inspection apparatus 10 may irradiate ultraviolet rays toward the coating film of the substrate. The irradiated ultraviolet rays can generate fluorescence by exciting a fluorescent dye mixed in the coating film. The additional light detector 140 of the inspection apparatus 10 may capture the fluorescence to obtain a two-dimensional image of the coating film of the substrate. The 2D image may be a 2D fluorescence image according to an embodiment.

The inspection apparatus 10 may derive one or more areas 3 on the substrate 2 according to a predetermined criterion based on the result of the photographic inspection. The inspection device 10 may derive the amount of coating applied to the substrate 2 from the two-dimensional image. The inspection apparatus 10 may obtain luminance information for each of a plurality of regions of the substrate 2 from the obtained two-dimensional image. When ultraviolet rays are irradiated, the luminance in each region of the coating film may be different depending on the amount of fluorescent dye. The inspection apparatus 10 may derive the amount of coating of the coating film in each region by using the luminance of each region.

After that, the inspection apparatus 10 can derive a certain area 3 based on the applied amount. For example, an area in which the application amount is less than a certain standard may be derived as a certain area 3. The inspection apparatus 10 may additionally perform a thickness measurement using the OCT part 170 as described above with respect to the derived region 3. The OCT part 170 of the inspection apparatus 10 acquires optical interference data for the derived region 3, and based on the obtained optical interference data, the thickness of the coating film applied to the corresponding region 3 on the substrate Can be measured.

In one embodiment, the additional light source 130 may be arranged to irradiate ultraviolet rays toward the substrate, and the relative position of the additional light source 130 with respect to the substrate, the irradiation angle of the ultraviolet rays, the brightness of the ultraviolet rays, etc. (configured) can In one embodiment, the inspection device 10 may include a plurality of additional light sources 130. In one embodiment, the additional light detector 140 may capture fluorescence generated from the coating film by ultraviolet rays. In one embodiment, the inspection device 10 may include a plurality of additional light detectors 140. The additional light detector 140 may be implemented by a Charged Coupled Device (CCD) or a Complementary Metal-Oxide-Semiconductor (CMOS).

10 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples a region for thickness measurement by the OCT part 170 according to an element arrangement according to an exemplary embodiment of the present disclosure. In one embodiment, the processor 110 derives a region 3 in which the amount of application derived through a two-dimensional image is less than or equal to a preset amount and a region 4 in which the arrangement of elements is the same or similar, and controls the OCT part 170 Thus, the thickness for this area 4 can be derived. In other words, the processor 110 may derive a region having the same or similar arrangement of devices based on the device arrangement information 1000 and perform thickness measurement using OCT on the region. Regions having the same or similar device arrangement may have similar thickness values of the applied coating films. A region having the same or similar device arrangement to any one region may have a similar coating thickness. In the present disclosure, the device arrangement information 1000 may be information indicating an arrangement of devices disposed on the substrate 2. The device arrangement information 1000 may indicate information such as positions, directions, and occupied sizes of devices mounted on the substrate 2 on the substrate 2.

First, as described above, the processor 110 may derive the area 3 in which the amount of application obtained through the two-dimensional image is less than or equal to a preset amount. In one embodiment, the processor 110 may measure the thickness for this area 3 using the OCT part 170. In addition, the processor 110 may derive a region 4 on the substrate 2 in which the derived region 3 and the device arrangement are the same. The corresponding region 4 may be selected from regions (ie, regions other than the first region) in which the amount of application derived through the two-dimensional image exceeds a preset amount. The processor 110 may derive the corresponding region 4 based on the device arrangement information 1000 described above. The processor 110 may use the OCT part 170 to derive the additionally derived thickness for the corresponding region 4. The processor 110 may control the light source 150 and the light detector 160 to obtain optical interference data generated by the laser light reflected from the corresponding region 4. The processor 110 may derive the thickness of the coating film applied to the region 4 based on the acquired optical interference data. In the present disclosure, that the processor 110 controls the light source 150 and the light sensor 160 to obtain optical interference data of a region means that the light source 150 irradiates a laser light toward a corresponding region, and It may mean that the detector 160 acquires optical interference data according to the interfering light generated from a corresponding one area.

In one embodiment, the processor 110 may derive a region 4 having a similar element arrangement to the region 3 derived by the two-dimensional image, and perform thickness measurement using OCT on the region 4 have. Whether the device arrangements are similar may be determined based on the device arrangement information 1000 for the two regions 3 and 4. The processor 110 calculates the similarity of the arrangement of the elements for the two regions based on the area occupied by the elements in the regions 3 and 4, the arrangement, type, shape, and electrode positions of the elements, and the calculated similarity It can be determined whether the arrangement of the devices in the two regions is similar according to this.

In one embodiment, the processor 110 may adjust the above-described luminance information according to the arrangement of elements on the substrate 2 and the degree of concentration of the elements, and derive the coating amount of the coating film in the corresponding region based on the adjusted luminance information. have. Specifically, the processor 110 may obtain device arrangement information 1000 indicating an arrangement of devices on the substrate 2 from the memory 120. The processor 110 may derive device density information 2000 for each region on the substrate 2 based on the device arrangement information 1000 described above. The processor 110 may adjust luminance information derived from a 2D image based on the device density information 2000. In a region of the substrate 2 with high device density, the application of the fluorescent dye may be uneven. In a region in which the device density is high, that is, the device is dense, due to the accumulation of the fluorescent dye, the luminance may be measured high. The processor 110 may adjust the obtained luminance information in consideration of the distortion of luminance according to the device density. Accumulated information indicating a relationship between device density and luminance may be used for this adjustment, and this information may be converted into a database and stored in the memory 120. The processor 110 may derive a coating amount for each region on the substrate 2 based on the adjusted luminance information.

11 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples a region for thickness measurement by the OCT part 170 according to an exemplary embodiment of the present disclosure. In one embodiment, the processor 110 derives a region 5 determined to have a defect on the substrate 2 based on the device arrangement information 1000 and the 2D image, and controls the OCT part 170 You can derive the thickness for this area. A portion of the substrate 2 or the coating film with predetermined defects, for example, cracks, peeling, irregularities, and bends, may have errors in measuring the amount of application through a two-dimensional photographic inspection. Accordingly, the area 5 determined to have a predetermined defect based on the device arrangement information 1000 and/or the 2D image may be additionally measured for the thickness of the coating layer using the OCT part 170.

The processor 110 may determine the region 5 on the substrate 2 that is determined to have a predetermined defect based on the device arrangement information 1000 and/or the 2D image obtained from the memory 120. The two-dimensional image may be a photograph of the actual substrate 2 and the shape of the coating film. The device arrangement information 1000 may indicate a shape of the substrate 2 and an expected coating type of a coating film according to a predetermined specification. The processor 110 may compare the device arrangement information 1000 and the 2D image to determine a region in which the current substrate 2 and the coating film have characteristics out of a predetermined standard. That is, the processor 110 may determine that the corresponding feature is a defect. The processor 110 can derive the region 5 in which the defect exists.

The processor 110 may derive the thickness of the derived region 5 by using the OCT part 170. The processor 110 may control the light source 150 and the light detector 160 to obtain optical interference data generated by the laser light reflected from the corresponding region 5. The processor 110 may derive the thickness of the coating layer applied to the corresponding region 5 based on the acquired optical interference data.

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

In addition, in one embodiment, the processor 110 derives a region including the electrode portion, based on the electrode position information 3000 indicating the position of the electrode of the elements on the substrate 2, and selects the OCT part 170. Control to perform additional thickness measurements for this area. In the present disclosure, the electrode position information 3000 may indicate a position of an electrode of devices on the substrate 2. For example, each of the devices may have an electrode portion for connecting the device and fine wiring on the substrate. This electrode can also be called the leg of a device or chip. The electrode position information 3000 may indicate where the electrodes of the device are located on the substrate 2. In general, the electrode portion of the device may have agglomeration of fluorescent dyes depending on the density of the device legs, and thus, thickness measurement based on a two-dimensional image may not be accurate. Accordingly, an additional thickness measurement using OCT is performed on a portion where the electrode of the device is located, thereby increasing the accuracy of the entire thickness measurement process.

The processor 110 may know where the electrodes of the elements are located on the substrate 2 based on the electrode position information 3000 obtained from the memory 120. The processor 110 may derive a region on the substrate 2 where the electrode is located. In one embodiment, the corresponding region may be selected from regions (ie, regions other than the first region) in which the amount of application obtained through the 2D image exceeds a preset amount.

The processor 110 may derive the thickness of the derived region using the OCT part 170. The processor 110 may control the light source 150 and the light detector 160 to obtain optical interference data generated by laser light reflected from a corresponding region. The processor 110 may derive the thickness of the coating film applied to the corresponding region based on the acquired optical interference data.

12 is a diagram illustrating a process in which the inspection apparatus 10 additionally samples an area adjacent to an area in which thickness measurement is to be performed by the OCT part 170 according to an embodiment of the present disclosure. In regions on the substrate 2 derived according to various embodiments of the present disclosure, that is, regions 7 in which thickness measurement is additionally performed using an OCT, the inspection apparatus 10 Further thickness measurements can also be carried out using OCT for the adjacent region 8.

The derived regions 7 are places where thickness measurement using OCT can be performed in addition to the 2D photographic inspection in terms of the accuracy of the coating film thickness measurement. Regions adjacent to the regions 7 may have characteristics similar to those of the region 7 in relation to the substrate 2 or the coating film. Accordingly, in order to ensure the accuracy of the entire thickness measurement process, additional thickness measurement using OCT may be performed on the adjacent area.

Here, when the substrate 2 is divided into a plurality of regions, the adjacent regions may refer to regions positioned adjacent to the corresponding region 7. In an embodiment, the adjacent area may mean an area facing a boundary line with the area 7 among a plurality of areas. In an embodiment, the adjacent area may mean an area located within a predetermined radius with respect to the center of the corresponding area 7 among a plurality of areas. In one embodiment, when the axes corresponding to the horizontal direction and the vertical direction of the substrate are respectively referred to as x-axis and y-axis, the adjacent regions are in the +x-axis direction, -x-axis direction, +y-axis direction, and It may be an area located in the y-axis direction and sharing a boundary line with the corresponding area 7. In one embodiment, the adjacent region may include a region that shares a vertex with the region 7 among a plurality of regions and is located diagonally.

In one embodiment, the processor 110 may re-perform the thickness measurement using the OCT based on the coating amount derived from the 2D image and the thickness value measured by the OCT part 170. According to an embodiment, a difference value between the qualitative thickness value of the coating film in the area that can be derived from the coating amount and the thickness value measured by OCT is derived, and when the difference value is greater than or equal to a predefined value, for the area Thickness measurement using OCT can be re-performed. In addition, according to an embodiment, based on the derived coating amount and thickness value, if the two values do not satisfy a predetermined criterion, the thickness measurement may be performed again. Here, the predetermined criterion may be a criterion used to determine that at least one of the derived coating amount or thickness is measured incorrectly, based on the relationship between the predetermined coating amount and the thickness. That is, when considering the application amount and thickness value, if it is determined that there is an error in the measurement, the measurement may be performed again. In addition, in one embodiment, the processor 110 is based on the coating amount of one area derived by the two-dimensional image and the thickness value of the area measured by the OCT part 170, for the adjacent area of the corresponding area. , It is possible to measure the thickness again by controlling the OCT part 170.

13 is a view showing an embodiment of a substrate inspection method, which can 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 a sequential order in the illustrated flowchart, each step may be performed in an order that may be arbitrarily combined by the present disclosure in addition to being performed sequentially. The description in accordance with this flowchart does not exclude making changes or modifications to the method or algorithm, and does not imply that any step is essential or desirable. In one embodiment, at least some of the steps may be performed in parallel, repetitively or heuristically. In one embodiment, at least some of the steps may be omitted or other steps may be added.

In performing a substrate inspection, the inspection apparatus 10 according to the present disclosure may perform a substrate inspection method according to various embodiments of the present disclosure. A substrate inspection method according to an embodiment of the present disclosure includes the step of irradiating a laser light toward a coating film applied to a region on a substrate (S100), a reference light generated by being reflected by the surface of the coating film, and the scattered by passing through the coating film. Acquiring optical interference data according to interference between measurement lights (S200), and/or deriving a thickness of the coating film corresponding to the one region based on the optical interference data (S300). .

In step S100, the light source 150 of the inspection apparatus 10 may irradiate laser light toward the coating film applied to a region on the substrate. In step S200, the light detector 160 may obtain optical interference data according to interference between the reference light generated by reflecting the laser light by the surface of the coating layer and the measurement light scattered by transmitting the laser light through the coating layer. In step S300, the processor 110 may derive the thickness of the coating film corresponding to the above-described region based on the optical interference data.

In one embodiment, the step of deriving the thickness of the coating film (S300), the processor 110, based on the optical interference data, obtaining a cross-sectional image representing the cross-section in the depth direction of the coating film and/or the cross-sectional image It may include determining the thickness of the coating film based on the boundary line of the image.

In one embodiment, the step of deriving the thickness of the coating film (S300) is a step in which the processor 110 obtains a plurality of cross-sectional images previously acquired for the one region from the memory and/or the processor 110 It may include determining a reference boundary line from a plurality of boundary lines on the cross-sectional image, and deriving a thickness of the coating film corresponding to the above-described area based on the reference boundary line.

In an embodiment, the reference boundary line may be a boundary line according to one of a mean value, a median value, and a mode of the plurality of boundary lines.

In an embodiment, the reference boundary line may be a boundary line according to an average value of boundary lines satisfying a preset criterion among the plurality of boundary lines.

In one embodiment, the substrate inspection method further includes, by the light detector 160, deriving a reflectance of the surface of the coating film based on the amount of light of the reference light and/or moving the light source when the reflectance is less than a predefined reflectance. I can. This movement can be performed by the moving part described above.

In one embodiment, the laser light is irradiated toward the above-described area along the first direction, and the reference light and the measurement light travel in the reverse direction of the first direction, and may be captured by the light detector. In one embodiment, the laser light may be directly irradiated onto the surface of the coating film without passing through a medium other than air.

Various embodiments of the present disclosure may be implemented as software in a machine-readable storage medium. The software may be software for implementing various embodiments of the present disclosure. The software may be inferred from various embodiments of the present disclosure by programmers in the art to which this disclosure belongs. For example, software may be a program including instructions (eg, code or code segment) that the device can read. The device is a device capable of operating according to a command called from a storage medium, and may be, for example, a computer. In one embodiment, the device may be the inspection device 10 according to embodiments of the present disclosure. In one embodiment, the processor of the device may execute a called command and cause components of the device to perform a function corresponding to the command. In one embodiment, the processor may be the processor 110 according to embodiments of the present disclosure. The storage medium may mean any type of recording medium in which data is stored, which can be read by a device. The storage medium may include, for example, ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like. In one embodiment, the storage medium may be the memory 120. In one embodiment, the storage medium may be implemented as a distributed form such as a computer system connected through a network. The software can be distributed and stored and executed in a computer system or the like. The storage medium may be a non-transitory storage medium. The non-transitory storage medium refers to a tangible medium regardless of whether data is semi-permanently or temporarily stored, and does not include a signal propagating in a transient manner.

Although the technical idea of the present disclosure has been described above by various embodiments, the technical idea of the present disclosure includes various substitutions, modifications, and changes that can be made within a range that can be understood by those of ordinary skill in the art to which the present disclosure belongs. Include. In addition, it is to be understood that such substitutions, modifications and changes may be included within the scope of the appended claims.

Claims (17)

A light source for irradiating laser light toward a region on the surface of the coating film applied on the substrate;
A light detector for acquiring optical interference data according to interference between the reference light generated by reflecting the laser light by the one region and the measurement light scattered by the laser light passing through the coating film;
A moving unit for moving the light source along two axial directions orthogonal to each other on a plane corresponding to the substrate; And
Deriving the reflectance of the one region of the coating film based on the amount of light of the reference light,
Determining whether the reflectance is less than a predefined reflectance,
According to the determination that the reflectance is equal to or greater than the predefined reflectance, the thickness of the coating film corresponding to the one region is derived based on the optical interference data,
And a processor configured to move the light source to irradiate laser light toward another area on the surface of the coating film by controlling the moving unit according to a determination that the reflectance is less than the predefined reflectance.
The method of claim 1,
The processor,
Acquiring a cross-sectional image representing a cross section in the depth direction of the coating film based on the optical interference data,
The substrate inspection apparatus for determining the thickness of the coating film based on the boundary line on the cross-sectional image.
delete delete The method of claim 1,
The light source irradiates the laser light toward the coating film along a first direction that is a normal direction to the plane corresponding to the substrate,
The optical detector captures the reference light and the measurement light traveling in a direction opposite to the first direction to obtain the optical interference data.
The method of claim 1,
The light source is disposed such that the laser light is directly irradiated to the coating film without passing through a medium other than air.
The method of claim 1,
The reflectance of the surface of the coating film with respect to the laser light is determined by a fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film,
The fluorescent dye mixing ratio is set to a value such that the reflectance exceeds a preset reference value.
The method of claim 1,
The coating film is formed of at least one material selected from acrylic, urethane, polyurethane, silicone, epoxy, UV (Ultra Violet) curing material and IR (Infra Red) curing material.
The method of claim 1,
The surface of the coating film is formed in a curved surface, substrate inspection apparatus.
Irradiating a laser light toward a region on the surface of the coating film applied on the substrate by the light source;
Acquiring optical interference data according to interference between the reference light generated by reflecting the laser light by the one area and the measurement light scattered by the laser light passing through the coating film;
Deriving a reflectance of the one region of the coating film based on the amount of light of the reference light;
Determining whether the reflectance is less than a predefined reflectance;
Deriving a thickness of the coating film corresponding to the one region based on the optical interference data according to a determination that the reflectance is equal to or greater than the predetermined reflectance; And
In accordance with a determination that the reflectance is less than the predefined reflectance, moving the light source along two axial directions perpendicular to each other on a plane corresponding to the substrate so that laser light is irradiated toward another area on the surface of the coating film Including a substrate inspection method.
The method of claim 10, wherein the step of deriving the thickness of the coating film:
Obtaining a cross-sectional image representing a cross-section of the coating film in a depth direction based on the optical interference data; And
And determining the thickness of the coating film based on the boundary line on the cross-sectional image.
delete The method of claim 10,
The laser light is irradiated toward the one region along a first direction that is a normal direction to the plane corresponding to the substrate, and the reference light and the measurement light proceed in a direction opposite to the first direction.
The method of claim 10,
The laser light is irradiated directly to the coating film without passing through a medium other than air.
The method of claim 10,
The reflectance of the surface of the coating film with respect to the laser light is determined by a fluorescent dye mixing ratio of the fluorescent dye mixed in the coating film,
The fluorescent dye mixing ratio is set to a value such that the reflectance exceeds a preset reference value.
The method of claim 10,
The coating film is formed of at least one material selected from acrylic, urethane, polyurethane, silicone, epoxy, UV (Ultra Violet) curing material and IR (Infra Red) curing material.
The method of claim 10,
The surface of the coating film is formed in a curved surface, the substrate inspection method.

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