CN109974599B

CN109974599B - Substrate inspection apparatus and substrate inspection method

Info

Publication number: CN109974599B
Application number: CN201811434729.4A
Authority: CN
Inventors: 洪映周; 洪德和; 金玟奎; 崔桢熏
Original assignee: Gaoying Technology Co ltd
Current assignee: Gaoying Technology Co ltd
Priority date: 2017-11-28
Filing date: 2018-11-28
Publication date: 2021-03-16
Anticipated expiration: 2038-11-28
Also published as: JP2019101038A; JP2019101037A; JP6734352B6; JP2020173269A; KR20190062190A; CN209399935U; CN113324487A; CN113324487B; JP6732858B2; JP6734352B2; JP6732858B6; KR102275556B1; CN109974598A; JP6955305B2; KR20200092905A; CN109974599A; KR102138622B1; CN209399934U; KR20190062189A; CN109974598B

Abstract

The present disclosure provides a substrate inspection apparatus. The substrate inspection apparatus of the present disclosure may include: a light source that irradiates laser light toward a coating film coated on one area on a substrate; an optical sensor that obtains optical interference data caused by interference between reference light generated by the laser light being reflected by the surface of the coating film and measurement light scattered by the laser light passing through the coating film; and a processor that derives 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

Technical Field

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

Background

In the process of processing the substrate, the substrate may be coated in order to protect the elements on the substrate. Such coating may be referred to as conformal coating. In order to confirm whether or not the coating film on the substrate generated by means of coating is uniformly coated to a given thickness, a thickness inspection of the conformal coating film may be performed.

For thickness inspection of the coating film, two-Dimensional (2-Dimensional) fluoroscopic photograph inspection may be performed. However, the two-dimensional image photographing inspection can only perform a qualitative inspection of the thickness of the coating film, and cannot measure an accurate thickness value of the coating film. In addition, two-dimensional image photographing inspection when the coating film is thin (e.g., about 30 μm), thickness measurement may be difficult.

For thickness inspection of the coating film, a method using OCT (Optical Coherence Tomography) may be used. However, when the thickness inspection of the coating film is performed using the OCT, a saturation (saturation) phenomenon of light occurs due to reflection of the reference mirror, and an error occurs in the thickness measurement. Further, it is difficult to miniaturize the OCT due to the components of the OCT, such as the reference mirror, the window glass, and the beam splitter.

Disclosure of Invention

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

As one aspect of the present disclosure, a substrate inspection apparatus may be provided. A substrate inspection apparatus of an aspect of the present disclosure may include: a light source that irradiates laser light toward a coating film coated on one area on a substrate; an optical sensor that obtains optical interference data caused by interference between reference light generated by the laser light being reflected by the surface of the coating film and measurement light scattered by the laser light passing through the coating film; and a processor that derives a thickness of the coating film corresponding to the one region based on the optical interference data.

In one embodiment, the processor may obtain a cross-sectional image showing a cross-section of the coating film in a depth direction based on the optical interference data, and determine the thickness of the coating film based on a boundary line on the cross-sectional image.

In one embodiment, a moving part that moves the light source may be further included.

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

In one embodiment, the light source may irradiate the laser light toward the coating film in a first direction, and the light sensor may capture the reference light and the measurement light traveling in a direction opposite to the first direction to obtain the light interference data.

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

In one embodiment, the reflectivity of the surface of the coating film to the laser light may be determined according to a fluorescent dye mixing ratio of fluorescent dyes mixed in the coating film, and the fluorescent dye mixing ratio may be set to a value such that the reflectivity exceeds a preset reference value.

In one embodiment, the coating film may be formed by means of at least one selected from acrylic, urethane, silicon, epoxy, uv (ultra violet) curing substance and ir (infra red) curing substance.

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

As one aspect of the present disclosure, a substrate inspection method may be proposed. A substrate inspection method of an aspect of the present disclosure may include: a step of irradiating laser toward a coating film coated on one area on a substrate; obtaining optical interference data caused by interference between reference light generated by the laser light being reflected by the surface of the coating film and measurement light scattered by the laser light passing through the coating film; and a step of 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 coated film may comprise: a step of obtaining a cross-sectional image showing a cross section of the coating film 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 one embodiment, the method may further include: a step of deriving a reflectance of the coating film surface based on a light amount of reference light; and moving the light source when the reflectivity is less than a predefined reflectivity.

In one embodiment, the laser may be irradiated toward the one region in a first direction, and the reference light and the measurement light may travel in a direction opposite to the first direction.

In one embodiment, the laser may directly irradiate the surface of the coating film without transmitting a medium other than air.

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

According to various embodiments of the present disclosure, the substrate inspection apparatus does not need a reference mirror or other components, and can measure the thickness of the coating film and reduce measurement errors caused by the saturation phenomenon of light.

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

Drawings

Fig. 1 is a diagram showing an example of an operation process of a substrate inspection apparatus according to an embodiment.

Fig. 2 is a diagram showing one embodiment of the operation process of the substrate inspection apparatus of the present disclosure.

Fig. 3 is a diagram showing a block diagram of the inspection apparatus 10 of various embodiments of the present disclosure.

Fig. 4 is a diagram showing a cross-sectional image and a boundary line displayed on the cross-sectional image according to an embodiment of the present disclosure.

Fig. 5 is a diagram showing a depth direction measurement range of the inspection apparatus 10 according to an embodiment of the present disclosure.

Fig. 6 is a diagram showing a process in which the processor 110 derives the thickness of the coating film based on a plurality of boundary lines according to an embodiment of the present disclosure.

Fig. 7 is a diagram showing a process in which the processor 110 excludes a part of the boundary line according to a predetermined reference according to one embodiment of the present disclosure.

Fig. 8 is a diagram showing an adjustment process of a thickness measurement area based on the reflectance of a coating film according to an embodiment of the present disclosure.

Fig. 9 is a diagram showing a procedure in which the inspection apparatus 10 of one embodiment of the present disclosure samples an area in which thickness measurement based on the OCT portion 170 is to be performed by photographic inspection using a fluorescent dye.

Fig. 10 is a diagram showing a procedure of additionally sampling an area where thickness measurement based on the OCT portion 170 is to be performed, according to the element arrangement, by the inspection apparatus 10 of one embodiment of the present disclosure.

Fig. 11 is a diagram showing a procedure in which the inspection apparatus 10 of one embodiment of the present disclosure additionally samples an area where thickness measurement based on the OCT portion 170 is to be performed, according to a defective area.

Fig. 12 is a diagram showing a procedure in which the inspection apparatus 10 of one embodiment of the present disclosure additionally samples an adjacent region of a region in which thickness measurement based on the OCT portion 170 is to be performed.

Fig. 13 is a diagram showing one embodiment of a substrate inspection method that may be performed by means of the inspection apparatus 10 of the present disclosure.

Detailed Description

The various embodiments described herein are exemplified for the purpose of clearly explaining the technical idea of the present disclosure, and are not limited to specific embodiments. The technical idea of the present disclosure includes various modifications (modifications), equivalents (equivalents), substitutes (alternatives), and embodiments in which all or a part of the embodiments are selectively combined from the embodiments described herein. The scope of the technical idea of the present disclosure is not limited to the various embodiments or the specific description thereof presented below.

Including technical or scientific terms, the terms used herein may have meanings that are generally understood by those of ordinary skill in the art to which the present disclosure belongs, as long as they are not defined differently.

Expressions such as "comprising", "may include", "have", "may have", etc., used herein mean the existence of the characteristic that is the object (e.g., function, operation, constituent element, etc.), and do not exclude the existence of other additional characteristics. That is, such expressions should be understood as encompassing open-ended terms that would include the possibility of other embodiments.

The use of the singular expression herein may include the plural unless it is different in the language, and the same applies to the singular expression recited in the claims.

As used herein, "first", "second" or "first", "second", etc., are used to distinguish one object from another object, without limiting the order or importance between the respective objects, insofar as the difference is not represented by the language, in referring to the plurality of the same objects.

As used herein, expressions of "A, B and C", "A, B or C", "A, B and/or C" or "A, B and at least one of C", "A, B or at least one of C", "A, B and/or at least one of C", etc., may mean the various listed items or all possible combinations of the listed items. For example, "at least one of a or B" may refer to (1) at least one a, (2) at least one B, (3) at least one a and at least one B, all inclusive.

The expression "part" word as used herein may mean software or a hardware constituent element such as an FPGA (field-programmable gate array) or an ASIC (application specific integrated circuit). However, the "unit" is not limited to hardware or software. The "unit" may be stored in an addressable storage medium, or may be configured to run one or more processors. In one embodiment, a "section" may include components such as software components, object-oriented software components, class components, and task components, as well as processors, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, worksheets, arrays, and variables.

The expression "based on" or "words" used in this document is used to describe one or more factors that affect the behavior or action determined or judged in a sentence or a text including the corresponding expression, and the expression does not exclude additional factors that affect the behavior or action determined or judged accordingly.

As used herein, the expression that a certain component (e.g., a first component) is "connected to" or "connected to" another component (e.g., a second component) means that the certain component is not only directly connected or connected to the another component, but also connected or connected via a new another component (e.g., a third component).

The expression "configured to" used herein may have meanings such as "set to", "have" ability "," changed to "," formed to ", and" allowed to go to ", depending on the theory. The corresponding expression is not limited to the meaning of "specially designed in hardware", and for example, by a processor configured to perform a specific operation, it may mean a general-purpose processor (generic-purpose processor) capable of performing its specific operation by running software.

To illustrate the various embodiments of the present disclosure, a rectangular coordinate system may be defined having X, Y, and Z axes that are orthogonal to each other. The expressions "X-axis direction", "Y-axis direction", "Z-axis direction", and the like of the rectangular coordinate system used herein may mean both side directions in which each axis of the rectangular coordinate system extends, as long as they are not particularly defined differently in the corresponding description. The + sign added to the front of each axial direction may mean a positive direction which is one of the two lateral directions extending in the respective axial directions, and the-sign added to the front of each axial direction may mean a negative direction which is the remaining one of the two lateral directions extending in the respective axial directions.

In the present disclosure, a substrate (substrate) functions as a board or a container for mounting a device such as a semiconductor chip, and can function as a connection path for an electrical signal between the device and the device. The substrate may be used for integrated circuit fabrication, etc., and may be formed of a material such as silicon. The substrate may be, for example, a Printed Circuit Board (PCB), which may be referred to as a wafer (wafer) or the like according to an embodiment.

In the present disclosure, the coating film may be a thin film generated on the substrate by means of coating intended to protect the elements on the substrate. When the coating film is thick, the film may break and also affect the running of the substrate, and thus it is necessary to coat the coating film relatively thin and uniformly so as to prevent the coating film from breaking. In one embodiment, the coating film may be formed by means of at least one selected from acrylic, urethane, silicon, epoxy, uv (ultra violet) curing substance and ir (infra red) curing substance. The coating film formed by the above-mentioned substances can improve the reflectance of the surface of the coating film described later and/or the backscattering ratio of the coating film as compared with other coating films.

In the present disclosure, oct (optical Coherence tomography) may be an imaging technique that captures an image in a subject using an interference phenomenon of light. With OCT, an image of the inside of a display object body from the surface of the object body to the depth direction can be obtained. Generally, an interferometer is used as a base, and the resolving power in the depth direction of an object differs depending on the wavelength of light used. Compared with a confocal microscope (confocal microscope), which is another optical technique, it is possible to penetrate a subject body more deeply and obtain an image.

Various embodiments of the present disclosure are described below with reference to the drawings. In the drawings and the description thereof, the same or substantially the same (substitional equivalent) constituent elements may be given the same reference numerals. In the following description of various embodiments, the same or corresponding components may not be described repeatedly, but this does not mean that the corresponding components are not included in the embodiments.

Fig. 1 is a diagram showing an example of an operation process of a substrate inspection apparatus according to an embodiment. The substrate inspection apparatus of the illustrated embodiment may be of the type using a reference mirror. In the illustrated embodiment, the substrate inspection apparatus may further include a light source 150, a light sensor 160, a reference mirror 172, and/or a beam splitter 171.

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

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

The beam splitter 171 may adjust an optical path so that a part of the laser light received from the light source 150 is transmitted therethrough and directed toward the coating film of the substrate 2, and may adjust an optical path so that another part of the laser light is reflected and directed toward the reference mirror 172.

The optical path is adjusted so that a part of the laser light directed toward the coating film of the substrate 2 can be reflected in the coating film of the substrate 2. This reflected light may be referred to as measurement light. The measurement light proceeds toward the beam splitter 171 and may be transferred to the light sensor 160 by the beam splitter 171. The optical path is adjusted so that another part of the laser light directed toward the reference mirror 172 can be reflected by the reference mirror 172. This reflected light may be referred to as reference light. The reference light may be transmitted to the light sensor 160 through the beam splitter 171.

The optical sensor 160 may capture interference light formed by the measurement light and the reference light interfering with each other, and obtain optical interference data. In the present disclosure, the light interference data may mean data obtained from interference light generated by interference between measurement light of irradiated light reflected from an object and reference light of irradiated light reflected from a reference mirror or the like in measurement of the object based on the OCT method. An interference phenomenon occurs according to a difference in characteristics (optical path, wavelength, etc.) of the measurement light and the reference light, and the optical sensor can capture the interference phenomenon to obtain optical interference data. In addition, a cross-sectional image showing a cross section of the coating film in the depth direction may be generated based on the optical interference data. The optical interference data may also be referred to as an interference signal. The substrate inspection apparatus using the reference mirror can derive the thickness of the coating film applied on the substrate 2 by using the light interference data by the reference light and the measurement light.

Fig. 2 is a diagram showing one embodiment of the operation process of the substrate inspection apparatus of the present disclosure. The substrate inspection apparatus of the present disclosure may be embodied by means of the inspection apparatus 10 of the various embodiments. The substrate inspection apparatus of the present disclosure may be a type of substrate inspection apparatus that does not use the reference mirror as described above.

The inspection apparatus 10 of 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 may measure the thickness of the coating film by using the reflected light of the surface of the coating film, instead of using the aforementioned reference mirror or a predetermined window glass or the like.

Specifically, the inspection apparatus 10 of the present disclosure may include the light source 150 and/or the light sensor 160 without the reference mirror 172 or the beam splitter 171. The light source 150 of the inspection apparatus 10 may irradiate laser toward the coating film of the substrate 2. At this time, the laser may be irradiated in the first direction. The first direction may be a direction corresponding to a straight line inclined at a predetermined angle from a normal direction of the substrate. According to an embodiment, the first direction may also be the same as the normal direction of the substrate. An axis corresponding to a normal direction of the substrate may be referred to as a 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, or may irradiate the laser light through the optical fiber 174 and/or the convex lens 173.

In the present disclosure, the x-axis and the y-axis may be axes respectively included in planes corresponding to the surfaces of the substrate 2. The x-axis and the y-axis may be orthogonal to each other in the respective planes. Additionally, the x-axis and y-axis may be orthogonal to the aforementioned z-axis, respectively.

The laser light may be reflected at the surface of the coating film. Specifically, the laser light may be reflected at the first surface as shown. In addition, the laser light can be scattered backward through the coating film. The reflected light reflected on the surface of the coating film can function as the reference light, and the scattered light can function as the measurement light. That is, at this time, the reference light may be generated by the reflection of the laser light from the surface of the coating film, and the measurement light may be generated by the transmission and scattering of the laser light through the coating film. The reflected light (i.e., the reference light) and the scattered light (i.e., the measurement light) may travel in a direction opposite to the first direction, thereby generating interference light. That is, the irradiated laser beam and the above-described interference light (i.e., the reflected light and the scattered light) can travel coaxially and in opposite directions to each other. The light sensor may capture interference light (i.e., reflected light and scattered light) traveling in a direction opposite to the first direction. The light sensor 160 may obtain light interference data from the captured interference light. The processor 110 may obtain the optical interference data from the optical sensor 160, generate a cross-sectional image based thereon, and derive the thickness of the coating film applied at the corresponding region of the substrate 2.

As described above, in the aspect of the inspection apparatus 10 of the present disclosure for measuring the thickness of the coating film, the reflected light and the scattered light may perform the functions of the reference light and the measurement light of the substrate inspection apparatus using the reference mirror, respectively. In other words, the coating film of the substrate 2 itself can perform the aforementioned function of the reference mirror 172 according to its reflectance. In one embodiment, the inspection apparatus 10 may not dispose an additional constituent element such as a window glass on the coating film of the substrate 2. The inspection apparatus 10 of the present disclosure forms interference light by using the reflected light reflected by the surface of the coating film as reference light, and thus does not need to add an element such as a window glass.

Fig. 3 is a diagram showing a block diagram of the inspection apparatus 10 of various embodiments of the present disclosure. As described above, the inspection apparatus 10 may include the light source 150 and the light sensor 160, and may additionally include the processor 110 and the memory 120. In one embodiment, at least one of these components of the inspection apparatus 10 may be omitted, or other components may be added to the inspection apparatus 10. Additionally (additively) or alternatively (alternatingly), some of the constituent elements may be embodied in combination or in a plurality of individual units. At least some of the internal and external components of the inspection apparatus 10 may be connected to each other through a bus, a GPIO (general purpose input/output), an SPI (serial peripheral interface), an MIPI (mobile industry processor interface), or the like, and may transmit and receive data and/or signals.

The light source 150 may irradiate laser light toward the coating film of the substrate 2, as described above. The arrangement of the light sources 150, the relative position to the substrate, and the like may be variously configured (configured). In one embodiment, the light source 150 may be configured in the aforementioned z-axis. In one embodiment, the light source 150 may use a laser capable of changing a wavelength in a short time, and thus, light interference data corresponding to respective different wavelengths may be obtained. In one embodiment, the inspection device 10 may also include a plurality of light sources 150.

The light sensor 160 can capture interference light generated from the coating film by means of laser light. Specifically, the optical sensor 160 may capture interference light occurring by means of reflected light (i.e., reference light) reflected at the surface of the coating film by the laser light and scattered light (i.e., measurement light) scattered backward after being transmitted from the coating film to a predetermined depth. By using the light interference data obtained by capturing such interference light, a cross-sectional image with the coated film surface as a reference can be generated. In one embodiment, the light sensor 160 may be configured on the aforementioned z-axis. In one embodiment, the photosensor 160 may not be disposed on the z-axis, and in this case, the predetermined additional component may be adjusted so that the optical paths of the reflected light and the scattered light are directed toward the photosensor 160. In one embodiment, the inspection device 10 may include a plurality of light sensors 160. The light sensor 160 may be embodied by means of a CCD or CMOS. According to an embodiment, the light source 150 and the light sensor 160 may be collectively referred to as an OCT portion 170 of the inspection device 10.

The processor 110 may drive software (e.g., a program) to control at least one component of the inspection apparatus 10 connected to the processor 110. In addition, the processor 110 may perform operations related to the present disclosure, such as various calculations, processes, data generation, and processing. In addition, the processor 110 may load data or the like from the memory 120 or store the data in the memory 120.

The processor 110 may obtain light interference data based on the above-described interference light from the light sensor 160. The processor 110 may derive the thickness of the coating film applied to a region of the substrate 2 on which the laser light was irradiated, based on one or more light 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 data. The data stored in the memory 120 may include software (e.g., a program) as data obtained or processed or used by at least one of the constituent elements of the inspection apparatus 10. The memory 120 may include volatile and/or non-volatile memory. The memory 120 may store one or more optical interference data obtained from the light sensor 160. The memory 120 may store element arrangement information, element density information, and electrode position information, which will be described later.

In the present disclosure, the program may include, as software stored in the memory 120, an operating system for controlling the resources of the inspection apparatus 10, an application program, and/or middleware or the like that provides the application program with diverse functions so that the application program can utilize the resources of the inspection apparatus 10.

In one embodiment, the examination apparatus 10 may further comprise a communication interface (not shown in the figures). The communication interface may perform wireless or wired communication between the inspection apparatus 10 and a server or between the inspection apparatus 10 and other external electronic apparatuses. For example, the communication interface may perform Wireless communication based on LTE (long-term evolution), LTE-a (LTE advanced, long-term evolution advanced), CDMA (code division multiple access), WCDMA (wideband CDMA), WiBro (Wireless Broadband), WiFi (Wireless fidelity), Bluetooth (Bluetooth), NFC (near field communication), GPS (Global Positioning System), or GNSS (Global navigation satellite System), or the like. For example, the communication interface may perform wired communication based on a USB (universal serial bus), an HDMI (high definition multimedia interface), an RS-232 (managed standard232), or a POTS (plain old telephone service).

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

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

In one embodiment, the inspection apparatus 10 may further include a moving portion described later. The moving section can move the light source 150 and the OCT section 170 along the x, y, and z axes.

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

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

In one embodiment, the inspection device 10 may be a multi-modality device. For example, the examination device 10 may be a portable communication device, a computer device, a portable multimedia device, a wearable (wearable) device, or a combination of one or more of the foregoing devices. The inspection apparatus 10 of the present disclosure is not limited to the foregoing apparatus.

The various embodiments of the inspection device 10 of the present disclosure may be combined with each other. The embodiments may be combined according to all possible situations, and the combined embodiments of the inspection apparatus 10 also fall within the scope of the present disclosure. In addition, the internal/external components of the inspection apparatus 10 of the present disclosure may be added, changed, substituted, or deleted according to the embodiment. The internal and external components of the inspection apparatus 10 described above may be implemented as hardware components.

Fig. 4 is a diagram showing a cross-sectional image and a boundary line displayed on the cross-sectional image according to an embodiment of the present disclosure. As described above, the processor 110 can derive the thickness of the coating film applied on the predetermined region of the substrate 2 from the obtained optical interference data. The processor 110 may generate a cross-sectional image from the optical interference data, and derive the thickness of the coating film using information on the cross-sectional image.

In the present disclosure, the sectional image may mean a sectional plane in the depth direction of the object (coating film) displayed as a two-dimensional image in the measurement of the object based on the OCT method. The profile image may be generated based on measured light interference data. The sectional image may have boundary lines (boundary stripes) corresponding to interfaces between air and the coating film, and the substrate.

Specifically, the processor 110 may obtain a cross-sectional image as shown in the figure through light 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, that is, in the depth direction, of the substrate 2 and the coating film. That is, the sectional image can display the coating film and the inside of the substrate passing through from the surface of the coating film in the depth direction.

The illustrated cross-sectional image 4010 may be a cross-sectional image that can be obtained by means of a substrate inspection apparatus using the aforementioned reference mirror. The cross-sectional image 4010 may have one or more boundary lines 4050. The boundary line 4050 may be a boundary line corresponding to an interface between air and the coating film, that is, a boundary line corresponding to a surface of the coating film, or a boundary line corresponding to an interface between the coating film and the substrate 2 to the electrode coated by the corresponding coating film, respectively. The substrate inspection apparatus using the reference mirror may derive the thickness of the coating film using the interval between the boundary lines corresponding to the respective interfaces.

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 obtained. The substrate inspection apparatus can determine a boundary line representing an interface between air and the coating film from the illustrated cross-sectional image 4010. In addition, the substrate inspection apparatus can determine the boundary line representing the interface between the coating film and the substrate 2 coated with the corresponding coating film from the cross-sectional image 4010. The substrate inspection apparatus can derive the longitudinal distance between the two boundary lines determined on the cross-sectional image 4010, and determine the longitudinal distance as the thickness of the coating film.

On the other hand, when the substrate inspection apparatus (example: inspection apparatus 10) of the present disclosure is used, a cross-sectional image 4020 with respect to the coating film surface can 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 coated with the corresponding coating film or even the electrode. The processor 110 of the inspection apparatus 10 can derive the thickness of the coating film using the interval between the corresponding boundary line 4040 and the upper edge 4030 of the cross-sectional image 4020.

When it is the inspection apparatus 10 of the present disclosure, the processor 110 may perceive the boundary line 4040 representing the interface between the coating film and the substrate 2 coated with the corresponding coating film. In one embodiment, the processor 110 may determine a boundary line that first appears from the upper side of the cross-sectional image 4020 to the depth direction as the corresponding boundary line 4040. In addition, since the inspection apparatus 10 generates optical interference data by using the reflected light reflected from the surface of the coating film, the cross-sectional image can display a cross section in the-Z axis direction, i.e., in the depth direction from the surface of the coating film with the surface of the coating film as an origin. Therefore, the upper side 4030 of the cross-sectional image 4020 obtained by means of the inspection apparatus 10 may correspond to the surface of the coating film. The processor 110 may derive a longitudinal distance between the sensed boundary 4040 and the upper 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 (scaling factor) in the derived longitudinal distance to determine the derived value as the thickness of the coating film.

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

Fig. 5 is a diagram 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 means of a substrate inspection apparatus using the aforementioned reference mirror. The corresponding cross-sectional image 5010 may have a boundary line representing an interface between air and the coating film and a boundary line representing an interface between the coating film and a substrate (PCB). In addition, the illustrated cross-sectional image 5020 may be a cross-sectional image obtained by means of the substrate inspection apparatus (e.g., the inspection apparatus 10) of the present disclosure. The corresponding cross-sectional image 5020 may have a boundary line representing an interface between the coating film and the substrate (PCB).

In one embodiment, the cross-sectional image 5010 can be larger than the cross-sectional image 5020. That is, the cross-sectional image 5010 may have a larger data amount than the cross-sectional image 5020. This is because, with respect to measurement based on the inspection apparatus 10, unlike the case of using the reference mirror, reflected light reflected from the surface of the coating film is used as reference light, and thus the depth direction (-Z-axis direction) measurement range is limited to starting from the surface of the coating film.

In the illustrated cross-sectional view 5030, in order to obtain a meaningful measurement result, the substrate inspection apparatus using the reference mirror needs to have a measurement range 5040 in which all the height differences due to the components mounted on the substrate 2 are taken into consideration. However, in the case of the thickness measurement of the coating film by the inspection apparatus 10, a meaningful thickness measurement result can be obtained only by the measurement range 5050 corresponding to 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 the measurement of the thickness of the coating film, and can reduce the calculation capacity required for the processing of the measurement results and the memory required for the storage.

In addition, since the reference mirror is not used in the measurement of the thickness of the coating film by the inspection apparatus 10, the possibility of measurement error due to the saturation phenomenon of the reflected light can be reduced. If the light output of the irradiation light exceeds a predetermined amount, the amount of reflected light also increases, and the interference signal is saturated. If the state reaches the saturation state, an interference signal appears regardless of an interference signal generated by the measurement object, which hinders accurate measurement. This saturation phenomenon is more likely to occur when a reference mirror having a high reflectance is used. The inspection apparatus 10 eliminates the use of a reference mirror, so that measurement errors due to a saturation phenomenon can be reduced.

Fig. 6 is a diagram showing a process in which the processor 110 derives the thickness of the coating film based on a plurality of boundary lines according to an embodiment of the present disclosure. In one embodiment, the inspection apparatus 10 may derive the thickness of the coating film corresponding to a predetermined region using a plurality of sectional images stored in a memory, which are obtained in advance for the respective regions. For this purpose, a plurality of sectional images can be obtained by a plurality of measurements and stored in a memory. Therefore, the inspection apparatus 10 can derive the thickness of the coating film while minimizing the influence of noise.

As previously described, processor 110 may obtain a cross-sectional image based on one or more optical interference data. The substrate inspection apparatus may repeat a plurality of measurements to obtain a plurality of sectional images 6010 with respect to a predetermined region of the substrate, and the plurality of sectional images may be stored in the memory. The plurality of sectional images 6010 may respectively display a section in the-z axis, i.e., the depth direction, of the coating film of the substrate 2. The plurality of sectional images 6010 may have boundary lines 6020 representing interfaces between the coating films and the substrate 2, respectively.

The processor 110 may obtain a plurality of boundary lines 6020 from each of the cross-sectional images 6010. The processor 110 may decide a boundary line of one of the plurality of boundary lines 6020 as a boundary line 6030 representing an interface between the coating film and one region of the substrate 2 coated by the corresponding coating film. The processor 110 may derive the thickness of the coating film based on the determined boundary line in the manner described above.

In one embodiment, the processor 110 may derive an average (mean), a median (mean), or a mode (mode) of the plurality of boundary lines 6020, which will be based on the boundary line of the average, median, or mode as the boundary line 6030 representing the interface between the coating film and the substrate 2. The processor can derive the thickness of the coating film corresponding to one region of the corresponding interface based on the decided boundary line 6030.

In the present disclosure, the average value may be a value obtained by dividing the total number of samples after adding the values of all samples. In the present disclosure, an intermediate value may mean a value located at the center of all sampled values. The sampled values may be arranged from small to large, with the value at the center being the median value when the number of samples is odd, and the average of the two values at the center being the median value when the number of samples is even. In the present disclosure, the mode value may mean a value that occurs most frequently among sampled values. In particular, in the present disclosure, the average value, the median value, or the mode value of the boundary line may mean an average value, a median value, or a mode value of the position coordinates that the corresponding boundary line has in the corresponding cross-sectional image. That is, when the sectional image is regarded as a plane composed of x and y axes, each point of the boundary line in the corresponding sectional image may have x and y coordinate values. In the plurality of cross-sectional images 6010, an average value, an intermediate value, or a mode value of the x and y coordinate values included in each of the plurality of boundary lines 6020 may be derived, and the boundary line determined by the derived coordinate values may be a boundary line 6030 determined by the average value, the intermediate value, or the mode value.

Fig. 7 is a diagram showing a process in which the processor 110 excludes a part of the boundary line according to a predetermined reference according to one embodiment of the present disclosure. In one embodiment, the processor 110 may derive an average value of the plurality of boundary lines 6020, and determine a boundary line that will become a basis for deriving the thickness of the coating film using only the remaining boundary lines after excluding the boundary line that exceeds the derived average value by more than a predetermined ratio. This may be by excluding a considerable number of boundary lines out of the plurality of boundary lines 6020 beyond the established range, in order to perform coating film thickness measurement excluding values resulting from significant measurement errors. More accurate thickness measurements can thereby be achieved.

In particular, the processor 110 may derive a first average value for the plurality of boundary lines 6020. The derivation of the average value of the boundary line may be performed as described above. The processor 110 may exclude boundary lines 7030 that exceed the derived first average established ratio among the plurality of boundary lines 6020. That is, when the range decided by the predetermined ratio of the derived first average value is the region between the illustrated broken lines 7020, the boundary line 7010 included in the corresponding region remains, and the boundary line 7030 beyond the corresponding region may be excluded from later processing. The processor 110 may derive a second average of the remaining boundary lines 7010 excluding boundary lines 7030 that exceed the predefined ratio. The average derivation process for the boundary line may be performed as described previously. The processor 110 may determine the boundary line determined by the derived second average value as a boundary line representing the interface between the coating film and the substrate 2. The processor may derive a thickness of the coating film corresponding to one region of the corresponding interface based on the decided boundary line.

In one embodiment, rather than using the average value, processor 110 may perform the actions described above that exclude predetermined boundary lines using intermediate or mode values. For example, the processor 110 may derive a first intermediate value of the plurality of boundary lines 6020, exclude boundary lines exceeding the first intermediate value by a predetermined ratio, and determine boundary lines determined by a second intermediate value of the remaining boundary lines as boundary lines to be a basis for deriving the coating film thickness. The same is true for the mode values. In one embodiment, the mean, median, mode values may also be used in combination with each other.

Fig. 8 is a diagram showing an adjustment process of 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 coating film surface is a predetermined reference value or more, the inspection apparatus 10 not using the reference mirror may be used. The predetermined reference value may be a minimum reflectance required for the coated film surface to perform the function of the reference mirror 172. In the thickness measurement of the present disclosure without using the reference mirror, the reflectance of the coating film surface may mean a ratio between reflected light (i.e., reference light) generated by reflection from the coating film surface and laser light irradiated to the coating film.

In one embodiment, the inspection apparatus 10 may derive the reflectance of the coated film based on the light amount of reflected light (i.e., reference light) caused by the coated film surface, and based on the reflectance, move the light source 150 and even the OCT part 170, perform thickness measurement. Since the inspection apparatus 10 that does not use the reference mirror obtains the optical interference data based on the reflectance of the coating film, a more meaningful measurement result can be obtained by finely adjusting the measurement target spot according to the reflectance of the coating film.

Specifically, the optical sensor 160 can measure the amount of reference light when capturing interference light caused by the reflected light (i.e., reference light) and the scattered light (i.e., measurement light). The processor 110 may derive the reflectance in the z-axis direction in the corresponding region of the coating film surface based on the measured light amount of the reference light caused by the coating film. The z-axis reflectance may mean a ratio of reflection of the irradiated laser light in the + z-axis direction.

When the derived reflectance is equal to or higher than the predetermined reflectance, the processor 110 determines that one or more pieces of optical interference data formed by the corresponding reference light are effective optical interference data, and can derive the thickness of the coating film using the corresponding optical interference data. The predetermined reflectance may be the above-mentioned predetermined reference value as the minimum reflectance required for the coating film to perform the reference mirror action.

The processor 110 may move the light source 150 and thus the OCT portion 170 so that the laser light is irradiated toward the other area 8020 adjacent to the initial measurement target area 8010 when the derived reflectance is less than the predefined reflectance. In one embodiment, the inspection device 10 may further include a moving part. The moving part may move the light source 150 and thus the OCT part 170 in the x-axis, y-axis, and/or z-axis directions. As described previously, the x-axis and the y-axis, which are axes included in planes respectively corresponding to the surfaces of the substrates 2, may be orthogonal to each other on the respective planes, and the z-axis may be an axis corresponding to the normal direction of the substrates. The x-axis and y-axis may be orthogonal to the aforementioned z-axis, respectively. The processor 110 may control the moving section to move the light source 150 and thus the OCT part 170 in the x-axis and/or y-axis direction so that the laser light is irradiated toward the other area 8020 adjacent to the initial measurement target area 8010.

In one embodiment, the processor 110 can control the moving part to adjust the position of the light source 150, and thus the OCT component 170, in the z-axis based on the obtained resolution of one or more captured interfering lights. That is, the moving section may move the light source 150 and thus the OCT part 170 in the z-axis direction according to the resolution of the captured interference light. Since the interference light is used to capture an interference phenomenon caused by the reflected light (i.e., the reference light) and the scattered light (i.e., the measurement light), whether or not the interference phenomenon is sufficiently generated can be determined by a phase difference determined by a movement path of the laser light, the reflected light, and the scattered light. The processor 110 can control the moving part to adjust the position of the light source 150 and thus the OCT part 170 on the z-axis, thereby performing adjustment of the interference signal aimed at obtaining more definite interference light.

In the illustrated adjustment process 810 of the measurement region, the OCT portion 170 can be moved by means of a moving portion. Therefore, the measurement target region of the OCT part 170 or even the laser-irradiated region 8010 can be moved along the x-axis or the y-axis. This is probably because the reflectance of the coating film in the original region 8010 cannot reach a predetermined reference. The new irradiation region 8020 may be determined such that the measured thickness of the coating film corresponding to the new irradiation region 8020 can be regarded as or approximated to the adjoining region of the thickness of the coating film corresponding to the original region 8010. The adjacent region to one region will be described later. The new irradiation region 8020 may be determined as a region in which the + z-axis direction reflectance of the reference light is equal to or higher than a predetermined reference, unlike the original region 8010. In one embodiment, the new irradiation region 8020 may be determined as a region in which the + z-axis direction reflectance of the reference light is higher than the original region 8010 by a predetermined ratio or more.

When the process is observed in a cross section 820, the light source 150 is moved by the moving portion, and the laser light can be irradiated from the original irradiation region 8010 to the new irradiation region 8020. In the illustrated embodiment, the reflectance of the coating film in the + z-axis direction may be less than the predetermined reference in the original irradiation region 8010. This is probably because the surface of the coating film in the original irradiation region 8010 is not parallel to the normal line of the substrate, but is inclined at a predetermined angle or more. In addition, the moving section may move the light source 150 and even the OCT part 170 in the z-axis direction based on the resolution of the captured interference light.

In one embodiment, the irradiation angle of the irradiated laser light may be adjusted so that the reflectance of the coating film surface reaches a reference value or more. In one embodiment, laser light may be irradiated to a region of the surface of the coating film parallel to the substrate so that the reflectance of the surface of the coating film reaches a reference value or more.

In one embodiment, the reflectivity of the surface of the coating film may be determined according to the fluorescent dye mixing ratio of the corresponding coating film. In one embodiment, the coated film mixed with the fluorescent dye may have a higher reflectance of the surface of the coated film than that of the other substrate. The higher the mixing ratio of the fluorescent dye of the coating film, the higher the reflectance of the surface of the coating film will be. That is, if the coating film mixed with the fluorescent dye is used, the reflectance of the coating film surface increases, and therefore, the thickness measurement based on the inspection apparatus 10 not using the reference mirror can be easily performed. In one embodiment, the fluorescent dye mixing ratio of the coating film may be set to a value such that the reflectance of the surface of the coating film exceeds a reference value set in advance. According to the embodiment, the reference value may be a minimum reflectance required for the coating film surface to perform the function 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 backscattering ratio of the coating film may also be determined according to the fluorescent dye mixing ratio of the corresponding coating film. In one embodiment, the coated film mixed with the fluorescent dye may have a higher backscattering ratio than the other substrate. In the thickness measurement based on the inspection apparatus 10 of the present disclosure that does not use the reference mirror, the backscattering ratio of the coating film may mean a ratio between the scattered light (i.e., the measurement light) scattered rearward and the laser light irradiated to the coating film. The higher the mixing ratio of the fluorescent dye of the coating film, the higher the rear scattering ratio of the coating film will be. That is, if the coating film mixed with the fluorescent dye is used, the backscattering ratio of the coating film increases, and therefore, the thickness measurement based on the inspection apparatus 10 not using the reference mirror can be easily performed. In one embodiment, the fluorescent dye mixing ratio of the coating film may be set to a value such that the backscattering ratio of the coating film exceeds a reference value set in advance.

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 in 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 a curved surface, the thickness measurement based on the inspection apparatus 10 not using the 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 procedure in which the inspection apparatus 10 of one embodiment of the present disclosure samples an area in which thickness measurement based on the OCT portion 170 is to be performed by photographic inspection using a fluorescent dye. In one embodiment, the inspection apparatus 10 may perform a photo-taking inspection using a fluorescent dye for the entire area of the substrate, derive a specific area from a predetermined reference based on the inspection result, and perform OCT-based coating film thickness measurement for the derived area.

The inspection apparatus 10 may first perform a photo-taking inspection using a fluorescent dye on the substrate 2. The photo taking examination may be a fluoroscopic photo taking examination. For this inspection, a fluorescent dye may be mixed in advance in the coating film applied on the substrate 2. According to one embodiment, the inspection device 10 of the present disclosure may further include a supplemental light source 130 and/or a supplemental light sensor 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 may excite the fluorescent dye mixed in the coating film to generate fluorescence. The additional photosensor 140 of the inspection apparatus 10 can capture the fluorescence to obtain a two-dimensional image about the substrate coating film. The two-dimensional image may be a two-dimensional fluorescence image, according to an embodiment.

The inspection apparatus 10 may derive one or more regions 3 on the substrate 2 based on the result of the photographic inspection based on a predetermined reference. The inspection apparatus 10 can derive the coating amount of the coating film coated on the substrate 2 from the two-dimensional image. The inspection apparatus 10 can obtain luminance (luminance) information on each of the plurality of regions of the substrate 2 from the obtained two-dimensional image. If ultraviolet rays are irradiated, brightness in each region of the coating film differently appears according to the amount of the fluorescent dye. The inspection apparatus 10 can derive the coating amount of the coating film in each region by using the brightness of each region.

Then, the inspection apparatus 10 may derive the established region 3 based on the coating amount. For example, a region where the coating amount is equal to or less than a predetermined reference may be derived as the predetermined region 3. The inspection apparatus 10 can additionally perform the thickness measurement using the OCT portion 170 as described above with respect to the derived region 3. The OCT part 170 of the inspection apparatus 10 can obtain the optical interference data on the derived region 3, and additionally measure the thickness of the coating film coated on the corresponding region 3 on the substrate based on the obtained optical interference data.

In one embodiment, the additional light source 130 may be disposed 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, and the like may be variously configured (configured). In one embodiment, the inspection device 10 may include a plurality of supplemental light sources 130. In one embodiment, the further light sensor 140 may capture fluorescence occurring from the coated film by means of a laser. In one embodiment, the inspection device 10 may include a plurality of additional light sensors 140. The additional photosensor 140 may be implemented by a CCD (charge Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor).

Fig. 10 is a diagram showing a procedure of additionally sampling an area where thickness measurement based on the OCT portion 170 is to be performed, according to the element arrangement, by the inspection apparatus 10 of one embodiment of the present disclosure. In one embodiment, the processor 110 may derive a region 3 in which the coating amount derived from the two-dimensional image is a preset amount or less and a region 4 in which the arrangement of elements is the same or similar, control the OCT portion 170, and derive the thickness with respect to the region 4. In other words, the processor 110 may derive a region in which the arrangement of elements is the same or similar, for which thickness measurement with OCT is performed, based on the element arrangement information. The elements are arranged in the same or similar areas, and the thickness values of the coated films to be coated will be similar. Regions of the element arrangement that are the same as or similar to a region will have similar coating film thicknesses. In the present disclosure, the element arrangement information may be information showing the arrangement of elements arranged on the substrate 2. The element arrangement information may indicate information such as the position, direction, and occupied size of the element mounted on the substrate 2.

First, the processor 110 can derive the region 3 in which the coating amount obtained from the two-dimensional image is equal to or less than the preset amount, as described above. In one embodiment, the processor 110 can measure the thickness for the region 3 using the OCT component 170. The processor 110 may on this basis derive the component arrangement as one area 4 on the same substrate 2 as the derived area 3. The corresponding area 4 may be selected among areas in which the coating amount derived from the two-dimensional image exceeds a preset amount (i.e., areas other than the first area). The processor 110 may derive the corresponding area 4 based on the aforementioned element arrangement information. The processor 110 may derive the thickness of the corresponding region 4 for the additional derivation using the OCT part 170. The processor 110 may control the light source 150 and the light sensor 160 to obtain light interference data generated by means of the laser light reflected from the respective area 4. The processor 110 may output information about the thickness of the coating film applied at the corresponding region 4 based on the obtained optical interference data. In the present disclosure, the processor 110 controlling the light source 150 and the light sensor 160 to obtain the light interference data of one region may mean that the light source 150 irradiates laser light toward the corresponding one region, and the light sensor 160 obtains the light interference data determined by the interference light generated from the corresponding one region.

In one embodiment, the processor 110 may derive a region 4 with an arrangement of elements similar to the region 3 that was derived by means of the two-dimensional image, for which region 4 also thickness measurements with OCT may be performed. Wherein whether the element arrangement is similar or not can be judged based on the element arrangement information on the two areas 3, 4. The processor 110 may calculate the similarity of the element arrangement in the two regions based on the area occupied by the elements in the regions 3 and 4, the arrangement, type, form, electrode position of the elements, and the like, and determine whether the element arrangement in the two regions is similar based on the calculated similarity.

In one embodiment, the processor 110 may adjust the brightness information according to the component arrangement and the component density on the substrate 2, and derive the coating amount of the coating film in the corresponding region based on the adjusted brightness information. Specifically, the processor 110 may obtain element arrangement information representing the arrangement of elements on the substrate 2 from the memory 120. The processor 110 may derive element density information about each area on the substrate 2 based on the aforementioned element arrangement information. The processor 110 may adjust the luminance information derived from the two-dimensional image based on the element density information. In areas of the substrate 2 where the density of components is high, the application of the fluorescent dye may not be uniform enough. In a region where the density of elements is high, that is, a region where the elements are dense, the luminance is measured to be high due to the accumulation of the fluorescent dye. The processor 110 may adjust the obtained luminance information in consideration of the luminance distortion caused by the component density. In such an adjustment, information representing the accumulation of the relationship between element density and brightness may be used, which may be databased and stored in the memory 120. The processor 110 may derive coating amounts with respect to respective areas on the substrate 2 based on the adjusted brightness information.

Fig. 11 is a diagram showing a procedure in which the inspection apparatus 10 of one embodiment of the present disclosure additionally samples an area where thickness measurement based on the OCT portion 170 is to be performed, according to a defective area. In one embodiment, the processor 110 may derive a region 5 determined to be defective on the substrate 2 based on the element arrangement information and the two-dimensional image, control the OCT portion 170, and derive a thickness for the region. Predetermined defects of the substrate 2 or the coating film, such as portions having cracks (crack), peeling, unevenness, bending, etc., may have errors in the measurement of the coating amount through two-dimensional photographic inspection. Therefore, the coating film thickness measurement can be additionally performed by the OCT portion 170 based on the region 5 determined to have the predetermined defect based on the element arrangement information and/or the two-dimensional image.

The processor 110 may determine the region 5 on the substrate 2 determined to have the predetermined defect based on the element arrangement information and/or the two-dimensional image obtained from the memory 120. The two-dimensional image may be a photograph of the actual substrate 2 and the form of the coating film. The element array information can indicate the form of the substrate 2 and the expected coating form of the coating film according to a predetermined specification (specification). The processor 110 may compare the element arrangement information and the two-dimensional image to determine an area where the substrate 2 and the coating film now have features exceeding a predetermined specification. That is, the processor 110 may determine the corresponding feature as a defect. The processor 110 may derive the area 5 where the defect exists.

The processor 110 may derive a thickness for the derived region 5 using the OCT component 170. The processor 110 may control the light source 150 and the light sensor 160 to obtain light interference data generated by means of the laser light reflected from the respective area 5. The processor 110 may output information about the thickness of the coating film applied at the corresponding region 5 based on the obtained optical interference data.

In one embodiment, the derivation of the additional measurement target region based on the defective region may be performed independently of the derivation of the additional measurement target region based on the two-dimensional image.

In addition, in one embodiment, the processor 110 may derive a region including the electrode portion based on electrode position information representing a position of an electrode that the element has on the substrate 2, control the OCT portion 170, and perform additional thickness measurement on the region. In the present disclosure, the electrode position information may show the position of the electrode that the element has on the substrate 2. For example, the elements may have electrode portions for connecting the elements and fine wiring on the substrate, respectively. The electrodes may also be referred to as the component or the leads of the chip. The electrode position information may represent at which portion of the substrate 2 the electrode of the element is located. In general, the electrode portion of the element may have a coagulation phenomenon of the fluorescent dye with the density of the element pins, and thus, the thickness measurement based on the two-dimensional image may not be accurate enough. Therefore, the additional thickness measurement using OCT is performed at the portion of the element where the electrode is located, and the accuracy of the entire thickness measurement process can be improved.

The processor 110 can know where the electrodes of the elements on the substrate 2 are located based on the electrode position information obtained from the memory 120. The processor 110 may derive the area on the substrate 2 where the electrodes are located. In one embodiment, the corresponding region may be selected in a region where the coating amount obtained by the two-dimensional image exceeds a preset amount (i.e., a region other than the first region).

The processor 110 may derive a thickness for the derived region using the OCT component 170. The processor 110 may control the light source 150 and the light sensor 160 to obtain light interference data generated by means of the laser light reflected from the respective areas. The processor 110 may output information about the thickness of the coating film applied at the corresponding region based on the obtained optical interference data.

Fig. 12 is a diagram showing a procedure in which the inspection apparatus 10 of one embodiment of the present disclosure additionally samples an adjacent region of a region in which thickness measurement based on the OCT portion 170 is to be performed. In a region on the substrate 2 derived according to various embodiments of the present disclosure, that is, in the region 7 where the thickness measurement is additionally performed by the OCT, the inspection apparatus 10 may also perform the additional thickness measurement by the OCT with respect to the adjacent region 8 of the region 7.

The derived corresponding region 7 is where the thickness measurement with OCT can be additionally performed following the two-dimensional photographic examination in terms of the accuracy of the coating film thickness measurement. The adjoining areas of the respective areas 7 may be associated with the substrate 2 or the coating film, having similar characteristics as the respective areas 7. Therefore, to ensure the accuracy of the overall thickness measurement process, additional thickness measurements using OCT may be performed for the adjacent regions.

Here, the adjacent region may mean a region disposed adjacent to the corresponding region 7 when the substrate 2 is divided into a plurality of regions. In one embodiment, the adjacent region may mean a region among the plurality of regions that meets a boundary line of the corresponding region 7. In one embodiment, the adjacent area may mean an area located within a predetermined radius from the center of the corresponding area 7 among the plurality of areas. In one embodiment, when axes corresponding to the lateral and longitudinal directions of the substrate are referred to as X-axis and Y-axis, respectively, the adjacent regions may be regions located in the + X-axis direction, -X-axis direction, + Y-axis direction, -Y-axis direction of the corresponding region 7 and sharing a boundary line with the corresponding region 7. In one embodiment, the adjoining region may include a region of the plurality of regions that shares a vertex with the corresponding region 7 and is located on a diagonal line.

In one embodiment, the processor 110 may again perform thickness measurement with OCT based on the coating amount derived by means of the two-dimensional image and the thickness value measured by means of the OCT portion 170. According to the embodiment, a difference value between a qualitative thickness value of the coating film of the corresponding region derivable from the coating amount and a thickness value measured by means of the OCT may be derived, and when the difference value is a predefined value or more, the thickness measurement using the OCT may be performed again for the corresponding region. In addition, according to an embodiment, based on the derived coating amount and thickness value, when both values do not satisfy a predetermined reference, the thickness measurement may be performed again. Wherein the predetermined reference may be a reference used when it is determined that at least one value of the derived coating amount or thickness is measured erroneously, in view of the relationship between the measured coating amount and the thickness. That is, when the coating amount and the thickness value are considered, if it is determined that the measurement is erroneous, the measurement may be performed again. In addition, in one embodiment, the processor 110 may control the OCT portion 170 to measure the thickness again for the adjoining region of the respective region based on the coating amount of one region derived by means of the two-dimensional image and the thickness value of the region measured by means of the OCT portion 170.

Fig. 13 is a diagram showing one embodiment of a substrate inspection method that can be performed by means of the inspection apparatus 10 of the present disclosure. In the illustrated flowcharts, the steps of the method or algorithm of the present disclosure are described in sequence, but the steps may be performed in any combination of sequences in accordance with the present disclosure, in addition to being performed in sequence. The description based on the present flowchart does not exclude the case of applying variations or modifications to the method or algorithm, and does not imply that any step is necessary or preferred. In one embodiment, at least a portion of the steps may be performed in parallel, iteratively, or heuristically. In one embodiment, at least a portion of the steps may be omitted, or other steps may be added.

The inspection apparatus 10 of the present disclosure can perform the substrate inspection methods of the various embodiments of the present disclosure in performing substrate inspection. The substrate inspection method of one embodiment of the present disclosure may include: a step S100 of irradiating laser toward the coating film coated on one area on the substrate; a step S200 of obtaining optical interference data caused by interference between reference light generated by reflection of laser light on the surface of the coating film and measurement light scattered by transmission through the coating film; and/or a step S300 of deriving a thickness of the coating film corresponding to the one region based on the optical interference data.

In step S100, the light source 150 of the inspection apparatus 10 may irradiate laser toward the coating film coated on one area on the substrate. In step S200, the optical sensor 160 may obtain optical interference data caused by interference between reference light generated by reflection of the laser light by the surface of the coating film and measurement light scattered by the laser light passing through the coating film. In step S300, the processor 110 may derive the thickness of the coating film corresponding to the one region based on the optical interference data.

In one embodiment, the step S300 of deriving the thickness of the coating film may include: a step in which the processor 110 obtains a cross-sectional image showing a cross section in the depth direction of the coating film based on the optical interference data; and/or a step of determining the thickness of the coating film on the basis of the boundary line on the cross-sectional image.

In one embodiment, the step S300 of deriving the thickness of the coating film may include: a step in which the processor 110 obtains a plurality of sectional images obtained in advance for the one region from the memory; and/or the processor 110 determines a reference boundary line from a plurality of boundary lines on the plurality of cross-sectional images, and derives the thickness of the coating film corresponding to the one region based on the reference boundary line.

In one embodiment, the reference boundary line may be a boundary line determined by one of an average value (mean), a median value (mean), and a mode value (mode) with respect to the plurality of boundary lines.

In one embodiment, the reference boundary line may be a boundary line determined by an average value of boundary lines satisfying a preset reference among the plurality of boundary lines.

In one embodiment, the substrate inspection method may further include: a step in which the optical sensor 160 derives the reflectance of the coating film surface based on the amount of light of the reference light; and/or moving the light source when the reflectivity is less than a predefined reflectivity. The movement may be performed by means of the moving portion described above.

In one embodiment, the laser may be irradiated toward the one region in a first direction, and the reference light and the measurement light may travel in a direction opposite to the first direction and may be captured by the optical sensor. In one embodiment, the laser light may be directly irradiated to the surface of the coating film without passing through a medium other than air.

Various embodiments of the present disclosure may be embodied in software in a machine-readable storage medium. The software may be software for embodying various embodiments of the present disclosure. Software may be inferred from the various embodiments of the disclosure by programmers skilled in the art to which the disclosure pertains. For example, the software may be a program including machine-readable instructions (e.g., code or code segments). The machine may be a computer, for example, as a device that operates according to a command read from a storage medium. In one embodiment, the machine may be an inspection device 10 of an embodiment of the present disclosure. In one embodiment, a processor of the machine may execute the read command, and a constituent element of the machine may perform a function corresponding to the corresponding command. In one embodiment, the processor may be the processor 110 of an embodiment of the present disclosure. The storage medium may mean all kinds of recording media (recording media) that machine-readable stores data. The storage medium may include, for example, a ROM (read only memory), a RAM (random access memory), a CD-ROM (compact disc read only drive), a magnetic tape, a floppy 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 also be embodied in a form distributed through computer systems or the like connected via a network. The software may be distributed stored and executed in a computer system or the like. The storage medium may be a non-transitory (non-transitory) storage medium. By non-transitory storage medium is meant a medium (transitory medium) that is physically present regardless of whether data is stored semi-permanently or temporarily, and does not include a transitory (transitive) propagated signal (signal).

The technical ideas of the present disclosure are described above according to various embodiments, and include various substitutions, modifications, and alterations that can be achieved within a range that can be understood by a person having ordinary skill in the art to which the present disclosure pertains. It is to be understood that such substitutions, alterations and modifications are intended to be included in the appended claims.

Claims

1. A substrate inspection apparatus, comprising:

a light source that irradiates laser light toward a coating film coated on one area on a substrate;

an optical sensor that obtains optical interference data caused by interference between reference light generated by the laser light being reflected by the surface of the coating film and measurement light scattered by the laser light passing through the coating film;

a moving unit that moves the light source; and

and a processor configured to derive a reflectance of the surface of the coating film based on a light amount of the reference light, to derive a thickness of the coating film corresponding to the one region based on the light interference data when the reflectance is equal to or greater than a predefined reflectance, and to control the moving unit to move the light source to irradiate the laser light toward another region on the surface of the coating film adjacent to the one region when the reflectance is less than the predefined reflectance.

2. The substrate inspection apparatus according to claim 1,

the processor obtains a cross-sectional image showing a cross section in a depth direction of the coating film based on the optical interference data,

the thickness of the coating film is determined based on the boundary line on the cross-sectional image.

3. The substrate inspection apparatus according to claim 1,

the light source irradiates the laser light toward the coating film in a first direction,

the optical sensor captures the reference light and the measurement light traveling in the direction opposite to the first direction, and the optical interference data is obtained.

4. The substrate inspection apparatus according to claim 1,

the light source is disposed so that the laser light is directly irradiated to the surface of the coating film without transmitting a medium other than air.

5. The substrate inspection apparatus according to claim 1,

the reflectivity of the surface of the coating film to the laser is determined according to the 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.

6. The substrate inspection apparatus according to claim 1,

the coating film is formed by means of at least one selected from acrylic, urethane, silicone, epoxy, uv (ultra violet) curing substance and ir (infra red) curing substance.

7. The substrate inspection apparatus according to claim 1,

the surface of the coating film is formed in a curved surface.

8. A method of inspecting a substrate, comprising:

a step of irradiating laser toward a coating film coated on one area on a substrate;

obtaining optical interference data caused by interference between reference light generated by the laser light being reflected by the surface of the coating film and measurement light scattered by the laser light passing through the coating film;

a step of deriving a reflectance of the coating film surface based on the light amount of the reference light;

deriving a thickness of the coating film corresponding to the one region based on the optical interference data when the reflectance is equal to or greater than a predefined reflectance;

and a step of controlling the moving section to move the light source so that the laser beam is irradiated toward another region on the surface of the coating film adjacent to the one region, when the reflectance is less than a predetermined reflectance.

9. The substrate inspection method according to claim 8,

the step of deriving the thickness of the coated film includes:

a step of obtaining a cross-sectional image showing 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.

10. The substrate inspection method according to claim 8,

the laser beam is irradiated toward the one region in a first direction, and the reference light and the measurement light travel in a direction opposite to the first direction.

11. The substrate inspection method according to claim 8,

the laser light directly irradiates the surface of the coating film without transmitting a medium other than air.

12. The substrate inspection method according to claim 8,

13. The substrate inspection method according to claim 8,

14. The substrate inspection method according to claim 8,

the surface of the coating film is formed in a curved surface.