KR20240037761A - Inspection device and inspection method using the same - Google Patents

Abstract

The embodiment includes a stage on which a plurality of micro light emitting devices are arranged; an electron beam irradiation unit that radiates electron beams to the plurality of micro light emitting devices; a light detection unit that measures light emitted from the plurality of micro light emitting devices; and an electron beam guidance unit disposed between the electron beam irradiation unit and the plurality of micro light emitting devices.

Description

Inspection device and inspection method using the same {INSPECTION DEVICE AND INSPECTION METHOD USING THE SAME}

The embodiment relates to an inspection device and an inspection method that can inspect a micro light emitting device for defects in a non-contact manner.

Currently commercialized displays are represented by LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diodes). Recently, development of OLED displays has been active, but OLED displays have the problem of short lifespan and poor mass production yield.

Light Emitting Diode (LED) is one of the light emitting devices that emits light when current is applied. Light-emitting diodes can emit high-efficiency light at low voltage, providing excellent energy savings. Recently, the luminance problem of light emitting diodes has been greatly improved, and they are being applied to various devices such as backlight units of liquid crystal displays, electronic signs, indicators, and home appliances.

Light-emitting diodes containing compounds such as GaN and AlGaN have many advantages, such as having a wide and easily adjustable band gap energy, and can be used in a variety of ways, such as light-emitting devices, light-receiving devices, and various diodes. In particular, it has the advantages of low power consumption, semi-permanent lifespan, fast response speed, safety, and environmental friendliness.

Recently, research is being conducted on technology that uses micro light-emitting devices made of small light-emitting diodes as pixels in displays. Since many light-emitting devices are manufactured on a single wafer, it is important to accurately inspect the light-emitting devices for defects.

However, a non-contact device for inspection by emitting light from a plurality of micro light emitting devices has not yet been commercialized.

The embodiment provides an inspection device that inspects a micro light emitting device by emitting light in a non-contact manner.

The problem to be solved in the embodiment is not limited to this, and it will also include means of solving the problem described below and purposes and effects that can be understood from the embodiment.

An inspection device according to one aspect of the present invention includes a stage on which a plurality of micro light emitting devices are arranged; an electron beam irradiation unit that radiates electron beams to the plurality of micro light emitting devices; a light detection unit that acquires an image of light emitted from the plurality of micro light emitting devices; an electron beam guiding unit disposed between the electron beam irradiation unit and the plurality of micro light emitting devices; and a control unit that determines whether the plurality of micro light emitting devices are defective based on the optical image acquired by the light detection unit.

The electron beam guide may include a plurality of through holes through which the electron beam passes.

The ratio of the first distance between the electron beam irradiation unit and the micro light emitting device and the second distance between the electron beam irradiation unit and the electron beam guide unit (first distance: second distance) may be 1:0.6 to 1:0.99.

The electron beam guide unit may include a first electron beam guide unit disposed between the electron beam irradiation unit and the plurality of micro light emitting devices, and a second electron beam guide portion disposed between the first electron beam guide unit and the plurality of micro light emitting devices.

The electron beam irradiation unit includes an electrode layer, a plurality of emitters formed on the electrode layer to emit electrons toward the plurality of micro light-emitting devices, and a gate electrode spaced apart from the electrode layer, and the emitter includes a carbon nanotube. can do.

The voltage level applied to the electron beam guide may be higher than the voltage level applied to the gate electrode.

The plurality of micro light emitting devices include a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, and the first conductive semiconductor layer. The type semiconductor layer, the active layer, and the second conductivity type semiconductor layer may each emit light when irradiated with an electron beam.

and a filter that partially blocks light incident on the light detector, wherein the filter transmits the first light emitted from the active layer and the second light emitted from the first conductive semiconductor layer or the second conductive semiconductor layer. Light can be blocked.

and a filter array that partially blocks light incident on the light detector, wherein the filter array selectively transmits light in a first wavelength band among the entire wavelength band of first light emitted from the active layer of the plurality of micro light emitting devices. A first filter and a second filter that selectively transmits light in a second wavelength band different from the first wavelength band among the entire wavelength band of the first light, wherein the first light is selected from among blue light, green light, and red light. It could be any one.

The filter array may include a driver that selectively disposes the first filter and the second filter on the light detector.

It may include a vibration unit that applies vibration to the electron beam irradiation unit.

It includes a moving member that moves the stage or the electron beam guide, and as the stage or the electron beam guide moves, the micro light emitting device overlapping with the electron beam guide can be exposed through the through hole of the electron beam guide.

a chamber in which the stage, the electron beam irradiation unit, and the electron beam guidance unit are disposed; And it may include a vacuum pump that creates a vacuum inside the chamber.

a housing accommodating the electron beam irradiation unit and the electron beam guidance unit; and a movement module that moves the housing, wherein the electron beam emitted from the housing may be irradiated only to a portion of the plurality of micro light emitting devices.

The housing may be arranged to be inclined based on an imaginary line perpendicular to the stage.

An inspection method according to one aspect of the present invention includes forming a vacuum inside a chamber; irradiating an electron beam to a plurality of micro light emitting devices disposed inside the chamber; Measuring the light emission intensity of the plurality of micro light emitting devices; and determining whether the plurality of micro light emitting devices are defective, wherein the electron beam is accelerated by an electron beam guider disposed between the electron beam irradiator and the plurality of micro light emitting devices and is injected into the plurality of micro light emitting devices.

According to an embodiment, by providing an inspection device that inspects micro light emitting devices by emitting light in a non-contact manner, the inspection speed of a plurality of micro light emitting devices can be improved and damage to the light emitting devices can be prevented.

The various and beneficial advantages and effects of the present invention are not limited to the above-described content, and may be more easily understood through description of specific embodiments of the present invention.

1 is a conceptual diagram of an inspection device according to a first embodiment of the present invention;
Figure 2 is a diagram showing a state in which a light-emitting device emits light when an electron beam is irradiated;
Figure 3 is a diagram showing the principle by which a light-emitting device emits light by an electron beam;
Figure 4 is a diagram showing a state in which light emitted from a light emitting device is selectively incident by a filter;
Figure 5a is a diagram showing the mesh shape of the electron beam guide part,
Figure 5b is a diagram showing the cross-sectional shape of the electron beam guide part,
Figure 5c is a first modified example of Figure 5a,
Figure 5d is a second modification of Figure 5a,
Figure 6a is a diagram showing the electron beam irradiation unit,
Figure 6b is a modification of Figure 6a,
Figure 7 is a diagram showing the measured luminous intensity of a plurality of micro light-emitting devices;
Figure 8 is a photograph of a plurality of measured micro light emitting devices;
9 is a conceptual diagram of an inspection device according to a second embodiment of the present invention;
10 is a conceptual diagram of an inspection device according to a third embodiment of the present invention;
Figure 11 is a diagram showing the filter array,
Figure 12 is a diagram showing the state in which the filter array rotates,
Figure 13 is a diagram showing the process of selecting wavelengths by a filter,
Figure 14 is a conceptual diagram of an inspection device according to a fourth embodiment of the present invention;
Figure 15 is a diagram showing a plurality of light emitting devices partially connected,
Figure 16 is a modified example of Figure 15,
17 is a conceptual diagram of an inspection device according to a fifth embodiment of the present invention;
Figures 18a and 18b are diagrams showing the process of scanning a line-shaped inspection area;
19 is a conceptual diagram of an inspection device according to a sixth embodiment of the present invention;
Figure 20 is a conceptual diagram of an inspection device according to a seventh embodiment of the present invention;
Figure 21 is a plan view of the electron beam guide section;
Figure 22 is a diagram showing the state in which the electron beam guide is moving;
Figure 23 is a flowchart showing an inspection method according to an embodiment of the present invention;
Figure 24a is a diagram showing a state in which the electron beam measuring unit measures the uniformity of the electron beam;
Figure 24b is a diagram showing a state in which the first electrode layer and the electron beam measuring unit are divided into a plurality of areas.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms containing ordinal numbers, such as second, first, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, the second component may be referred to as the first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as the second component. The term and/or includes any of a plurality of related stated items or a combination of a plurality of related stated items.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Hereinafter, embodiments will be described in detail with reference to the attached drawings, but identical or corresponding components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted.

1 is a conceptual diagram of an inspection device according to a first embodiment of the present invention.

Referring to FIG. 1, the inspection device according to the embodiment includes a stage 530 on which a plurality of micro light-emitting devices 100 are arranged, an electron beam irradiation unit 200 that irradiates an electron beam to the plurality of micro light-emitting devices 100, and an electron beam irradiation unit. It includes an electron beam guiding part 300 disposed between 200 and a plurality of micro light emitting devices 100, and a chamber 500 forming a vacuum therein.

The chamber 500 accommodates the stage 530, the electron beam irradiation unit 200, and the electron beam guidance unit 300, and can prevent the electron beam from scattering by forming a vacuum therein.

The chamber 500 can maintain a vacuum of 10 ^-5 Torr or less, and the continuous use time can be more than 10,000 hours, but it is not necessarily limited to this and can be adjusted to satisfy various conditions for irradiating the electron beam to the micro light emitting device 100. You can. A vacuum pump 520 is disposed in the chamber 500 to control the vacuum pressure within the chamber 500.

The chamber 500 may further include a subchamber (not shown) that accommodates a plurality of wafers and a transfer member (not shown) that seats the wafers on the stage 530 .

A plurality of micro light emitting devices 100 may be placed on the substrate 10 on the stage 530 . The substrate 10 may be a sapphire (Al ₂ O ₃ ) wafer, which is a growth substrate, but is not necessarily limited thereto and may be a variety of substrates on which the micro light emitting device 100 is disposed. For example, the substrate 10 may be a transfer substrate onto which the micro light emitting device 100 is transferred, or it may be a display panel on which the transfer has been completed.

The micro light emitting device 100 may be a light emitting diode or an organic light emitting diode with a size of 1 μm to 200 μm. For example, the size of the micro light emitting device 100 may be 10㎛ to 60㎛, but it is not necessarily limited thereto, and light emitting devices of various sizes may be applied. For example, it may be a mini-sized light emitting device of 200㎛ to 500㎛, or it may be an RGB light emitting device of 1000㎛ or more.

The micro light emitting device 100 may be one of a blue light emitting device, a green light emitting device, and a red light emitting device. Since the micro light emitting device 100 functions as a pixel of a display, it can be designed to have any one of RGB wavelength bands.

The micro light emitting device 100 may have a plurality of light emitting structures separated on a growth substrate, but this is not necessarily limited, and some semiconductor layers may be connected to each other. In other words, the micro light emitting device 100 can be defined as a semiconductor structure in which each active layer is separated and can emit light independently.

The micro light emitting device 100 can be manufactured using Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and Molecular Beam Deposition (PECVD) methods. Epitaxy can be grown on a substrate using methods such as Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and sputtering.

The electron beam irradiation unit 200 may include a first electrode layer 210 and a plurality of emitters 220 formed on the first electrode layer 210 to emit electrons toward the plurality of micro light emitting devices 100. . The emitted electrons can move toward a plurality of micro light emitting devices. Here, an electron is a negatively charged particle, and an electron beam can be defined as a continuous flow of electrons with uniform kinetic energy and direction.

The first electrode layer 210 may include Al, Ag, Cu, Ti, Pt, Ni, Ir, or Rh, but is not necessarily limited thereto. For example, the first electrode layer 210 may be made of a transparent electrode such as ITO.

The emitter 220 may include carbon nanotubes (CNT), but is not necessarily limited thereto, and various materials and structures capable of emitting electrons may be applied.

At least a portion of the plurality of carbon nanotubes constituting the emitter 220 may have a shape extending in a vertical direction from the first electrode layer 210 toward the stage 530. However, it is not necessarily limited to this, and the plurality of carbon nanotubes may have a shape extending in the horizontal direction.

A plurality of emitters 220 may be uniformly arranged on the first electrode layer 210. Accordingly, electrons emitted from the plurality of emitters 220 can be uniformly irradiated to the plurality of micro light emitting devices 100.

The gate electrode 230 may be spaced apart from the plurality of emitters 220 by an insulating layer 240 . The gate electrode 230 may be placed higher than the emitter 220, but is not necessarily limited thereto, and may be placed at various positions that can form an electric field with the first electrode layer 210.

The first power supply unit 410 may apply voltage to the first electrode layer 210 and the gate electrode 230. A negative voltage may be applied to the first electrode layer 210, and a positive voltage may be applied to the first electrode layer 210.

The first power supply unit 410 can pulse-drive a high voltage of 1000V to 3000V at 1KHz or less. When a high voltage pulse is applied, an electric field may be formed between the first electrode layer 210 and the gate electrode 230. Accordingly, electrons emitted from the emitter 220 can move toward the micro light emitting device 100.

The electron beam guiding unit 300 may be disposed between the electron beam irradiating unit 200 and the plurality of micro light emitting devices 100. The electron beam guiding unit 300 may be a second gate electrode that is spaced apart from the first electrode layer 210 of the electron beam irradiating unit 200 and forms an electric field.

The second power supply unit 420 may accelerate the electron beam by applying a positive voltage of 8000V to 12000V to the electron beam guidance unit 300. The electron beam accelerated by the electron beam guide 300 is irradiated to the plurality of micro light-emitting devices 100, thereby causing the plurality of micro light-emitting devices 100 to emit light.

The electron beam irradiation unit 200 may be placed closer to the micro light emitting device 100 than the electron beam irradiation unit 200 .

The ratio of the first distance d1 between the electron beam irradiator 200 and the micro light emitting device 100 and the second distance d2 between the electron beam irradiator 200 and the electron beam guide 300 (first distance: 2 Distance) may be 1:0.6 to 1:0.99. If the distance ratio is less than 1:0.6 (e.g., 1:0.4), the distance between the electron beam guide unit 300 and the micro light-emitting device 100 increases, so that the electron beam has sufficient energy to reach the micro light-emitting device 100. You may not be able to get hired. Additionally, if the distance is greater than 1:0.99, the electron beam guide unit 300 may become too close to the micro light emitting device 100 and the uniformity of the electron beam may deteriorate.

The electron beam guide unit 300 may be formed with a plurality of through holes 310 to allow the electron beam to pass through. By way of example, the electron beam guiding unit 300 may have a mesh shape. However, it is not necessarily limited to this, and the electron beam guide unit 300 may have various structures that allow the electron beam to pass while forming an electric field that can accelerate the electron beam. For example, the electron beam guide unit 300 may be composed of an electrode through which an electron beam passes.

In order to increase uniformity, the electron beam guide 300 or stage 530 may be relatively moved. The moving member (320 in FIG. 5A) moves the electron beam guide unit 300 left and right to expose the hidden micro light emitting device 100 to the electron beam guide unit 300 through the through hole 310 of the electron beam guide unit 300. This can be investigated. However, it is not necessarily limited to this and the stage 530 can be moved left and right.

This electron beam guide unit 300 may have various advantages. According to the embodiment, since the electron beam guiding unit 300 is disposed between the electron beam irradiating unit 200 and the micro light emitting device 100, there is no need to apply voltage to the micro light emitting device 100. The structure of connecting power to the micro light emitting device 100 requires connecting power to each of the plurality of micro light emitting devices 100, so the circuit may become very complicated.

Additionally, a structure in which electrodes are placed on the back of the substrate 10 or on the stage 530 may not generate a strong electric field, so the electron beam may not be sufficiently accelerated. Accordingly, the electron beam may not be sufficiently injected into the light emitting device, so that the light emitting device may not have sufficient light emission intensity even if it is a normal device.

The light detection unit 600 may acquire light images emitted by the plurality of micro light emitting devices 100. The light detection unit 600 may be a camera equipped with a CCD, but is not necessarily limited thereto, and various imaging equipment capable of acquiring a light-emitting image of the micro light-emitting device 100 may be applied without limitation.

The light detector 600 is disposed on the window 510 of the chamber 500 and can measure the light emission intensity of the plurality of micro light emitting devices 100. Light emitted from the plurality of micro light emitting devices 100 may pass through the substrate 10 and be incident on the light detection unit 600.

However, the position of the light detection unit 600 is not limited to this and can be changed in various ways. For example, the light detection unit 600 and the window 510 may be disposed on the side of the chamber 500 or below the electron beam irradiation unit 200. That is, the light detection unit 600 can be placed in various positions to measure the light emission intensity of the micro light emitting device 100.

The light detection unit 600 may convert the collected light emission intensity (spectrum) or wavelength signal into an electrical signal and transmit it to the control unit 700. The control unit 700 may include a main processor that controls the overall inspection device.

The control unit 700 controls the operations of the electron beam irradiation unit 200, the first power supply unit 410, and the second power supply unit 420, and processes the measurement signal from the light detection unit 600 to evaluate the micro light emitting device 100. Map data containing the results can be output and defective devices can be detected.

The control unit 700 includes a memory (not shown) that stores data for an algorithm for controlling the operation of components in the inspection device or a program that reproduces the algorithm, and a processor that performs the above-described operations using the data stored in the memory. It can be implemented as (not shown). At this time, the memory and processor may each be implemented as separate chips, but this is not necessarily limited, and the memory and processor may be implemented as a single chip.

The control unit 700 may be connected to a storage unit (not shown) that stores processed data, and this storage unit may include Read Only Memory (ROM), Programmable ROM (PROM), Erasable Programmable ROM (EPROM), and Electrically Erasable Programmable Memory (EEPROM). Implemented with at least one of a non-volatile memory device such as ROM and flash memory, a volatile memory device such as RAM (Random Access Memory), or a storage medium such as a hard disk drive (HDD) or CD-ROM. It may be possible, but is not necessarily limited to this.

Figure 2 is a diagram showing a state in which a light-emitting device emits light when an electron beam is irradiated, Figure 3 is a diagram showing the principle of a light-emitting device emitting light by an electron beam, and Figure 4 is a diagram showing the light emitted from the light-emitting device by a filter selectively. This is a drawing showing the state of joining the company.

Referring to FIGS. 2 and 3 , each micro light emitting device 100 may include a first conductivity type semiconductor layer 110, an active layer 120, and a second conductivity type semiconductor layer 130. The first conductivity type semiconductor layer 110 may be implemented as a compound semiconductor such as group IIIV or group IIVI, and the first conductivity type semiconductor layer 110 may be doped with a first dopant.

The first conductive semiconductor layer 110 is a semiconductor material with a composition formula of Al _x In _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), InAlGaN, AlGaAs , may be formed of any one or more of GaP, GaAs, GaAsP, and AlGaInP, but is not limited thereto. When the first dopant is an n-type dopant such as Si, Ge, Sn, Se, Te, etc., the first conductive semiconductor layer 110 may be an n-type nitride semiconductor layer.

The active layer 120 may be disposed on the first conductive semiconductor layer 110. Additionally, the active layer 120 may be disposed between the first conductive semiconductor layer 110 and the second conductive semiconductor layer 130.

The active layer 120 is a layer where electrons (or holes) injected through the first conductive semiconductor layer 110 and holes (or electrons) injected through the second conductive semiconductor layer 130 meet. The active layer 120 transitions to a low energy level as electrons and holes recombine, and can generate light with a corresponding wavelength.

The active layer 120 may have any one of a single well structure, a multi-well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure, and the active layer 120 The structure is not limited to this. The active layer 120 can generate light in the visible wavelength range.

The second conductive semiconductor layer 130 may be disposed on the active layer 120. The second conductive semiconductor layer 130 may be implemented with a compound semiconductor such as group IIIV or group IIVI, and the second conductive semiconductor layer 130 may be doped with a second dopant.

The second conductive semiconductor layer 130 is a semiconductor material with a composition formula of In _x5 Al _y2 Ga _1-x5-y2 N (0≤x5≤1, 0≤y2≤1, 0≤x5+y2≤1) or AlInN. , AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second conductive semiconductor layer 130 doped with the second dopant may be a p-type semiconductor layer.

Referring to FIGS. 2 and 3 , the electron beam passing through the through hole 310 of the electron beam guide unit 300 may be irradiated to each semiconductor layer of the micro light emitting device 100. When an electron beam is irradiated to the micro light emitting device 100, the electron beam may collide in the semiconductor layer to generate an electron-hole pair. The generated electron-hole pairs can emit visible light through recombination.

The intensity of visible light emitted from the micro light emitting device 100 may be proportional to the intensity (or density) of the electron beam. Accordingly, the intensity (or density) of the electron beam can be adjusted so that light emitted from the micro light emitting device 100 can be detected to determine whether it is defective.

The micro light emitting device 100 may be one of a blue light emitting device, a green light emitting device, and a red light emitting device. Accordingly, the micro light emitting device 100 can emit light in the blue, green, or red wavelength range.

The electron beam injected into the micro light emitting device 100 may be injected not only into the active layer 120 but also into the first conductivity type semiconductor layer 110 and the second conductivity type semiconductor layer 130. Accordingly, the first conductive semiconductor layer 110 and the second conductive semiconductor layer 130 can also emit light.

For example, when the micro light emitting device 100 is a blue light emitting device, the first light (L1) in the blue wavelength band emitted from the active layer 120, the first conductive semiconductor layer 110, and the second conductive semiconductor layer 130 ) The second lights (L2, L3) in the yellow wavelength range emitted from ) may be mixed and emitted to the outside.

Referring to FIG. 4 , the filter 800 disposed in front of the light detection unit 600 may transmit only the first light L1 and block the second light L2 and L3. Therefore, since only the intensity of the first light L1 can be measured, it is possible to accurately determine whether the micro light emitting device 100 is defective.

The filter 800 may be a various band-pass filter that passes only the wavelength of the first light L1. For example, the filter 800 may have a plurality of high refractive index layers 801 and a plurality of low refractive index layers 802 alternately stacked so that only light in a specific wavelength range can pass through, but the structure of the filter 800 must be in this manner. It is not limited.

The filter 800 can be selectively applied depending on the inspection method. In the case of an inspection method without a filter, if the inspection target is a blue micro device, the device is judged to be normal if the intensity of blue light and yellow light at the detection wavelength are within a predetermined range, and if the intensity of blue light and yellow light exceeds the predetermined ratio, the device is judged to be normal. It may be judged to be a defective device. For example, if the intensity of blue light is significantly low, the micro light emitting device may be judged to be defective. When determining a defect in this way, the filter may be omitted.

The embodiment is a cathodoluminescence (CL) method in which the micro light-emitting device 100 emits light by irradiating an electron beam, so light emission is possible without damaging the light-emitting device, and a plurality of micro light-emitting devices 100 emit light at once by electron beam irradiation. Testing can be speeded up.

Scanning Electron Beam Microscope (SEM) is a microscope widely used to observe small-sized microstructures and shapes in the solid state. It has a deep depth of focus and makes it easy to observe three-dimensional images, such as complex surface structures and crystal shapes. It is an analysis equipment that can observe three-dimensional shapes at high magnification.

A scanning electron beam microscope uses an electron beam gun to generate and accelerate an electron beam, a focusing lens and objective lens to narrowly focus the electron beam, and a deflection coil to control the path of the electron beam after leaving the filament until it reaches the specimen. It consists of: However, the scanning electron beam microscope is different from the present embodiment, which irradiates the electron beam over a large area, in that it measures the chemical composition by irradiating the electron beam to a local area.

A field emission display is a display that arranges an array of field emission emitters 220, which are cold cathode electron beam sources, in a matrix form and emits cathode light by irradiating electron beam lines to a phosphor. However, the field emission display is different in that it does not have a structure that emits light from a light emitting diode.

In addition, the PL (Photoluminescence) method is a method in which light is injected into the sample and light is generated by excitation and recombination with the energy, while the cathodoluminescence (CL) method of the embodiment is a method in which the field-emitted electron beam is accelerated by an electric field. The difference is that energy is obtained and then injected into a light emitting diode to generate light.

FIG. 5A is a diagram showing the mesh shape of the electron beam guide, FIG. 5B is a diagram showing the cross-sectional shape of the electron beam guide, FIG. 5C is a first modification of FIG. 5A, and FIG. 5D is a second modification of FIG. 5A. FIG. 6A is a diagram showing an electron beam irradiation unit, and FIG. 6B is a modified example of FIG. 6A.

Referring to FIG. 5A, the electron beam guide unit 300 may have a mesh shape with a plurality of through holes 310 formed on the frame 311. Although the through hole 310 is illustrated as having a square shape, the through hole 310 may have various polygonal shapes or circular shapes.

The area of the plurality of through holes 310 in the electron beam guide unit 300 may be 80% to 95% of the total area. In order for the electron beam to be uniformly irradiated to the micro light emitting device 100, it is desirable that the area of the through hole 310 be increased. However, when the area of the through hole 310 becomes larger than 95%, the area of the electron beam guide 300 becomes smaller, which may reduce the effect of accelerating the electron beam.

Referring to Figure 5b, the electron beam guide unit 300 may have a first surface (300a) facing the electron beam irradiation unit 200 and a second surface (300b) facing the plurality of micro light emitting devices, and the second surface (300b) 300b) may have a curvature. Accordingly, the area of the second surface 300b may be larger than the area of the first surface 300a.

According to this configuration, the electron beam passing through the electron beam guide unit 300 is bent by the attraction force with the second surface 300b and can be more uniformly irradiated to the plurality of micro light emitting devices 100.

Referring to FIG. 5C, the electron beam guide unit 300 may include a plurality of through holes 310 extending long in one direction. That is, it can have various shapes other than the mesh shape. The area of the electron beam guide 300 may have an area corresponding to the plurality of light emitting elements 100, but is not necessarily limited thereto. For example, as shown in FIG. 5D, the electron beam guiding unit 300 may include at least one through hole 310 extending long in one direction. That is, the area of one through hole 310 may be larger than the area of one or more light emitting devices.

According to the embodiment, it may be important that the electron beam is uniformly irradiated to the plurality of micro light emitting devices 100. Accordingly, the emitter 220 may be selected from various structures that emit a uniform electron beam.

Referring to FIG. 6A, the first electrode layer 210 is disposed on the support substrate 10, and the emitter 220 may be formed of a plurality of carbon nanotubes. A plurality of carbon nanotubes may be grown directly on the first electrode layer 210, or the carbon nanotubes may be grown on a separate substrate and then transferred to the first electrode layer 210. If the separate substrate is a conductive substrate, the conductive substrate itself may be laminated on the first electrode layer 210.

A plurality of carbon nanotubes may be partitioned by an insulating layer 240. The gate electrode 230 may be disposed on top of the insulating layer 240, but the location of the gate electrode 230 is not particularly limited.

Referring to FIG. 6B, the emitter 220 may have a structure in which the end is formed to be sharp to facilitate the emission of electrons. In addition, the configuration of the electron beam irradiation unit 200 can be any known emitter configuration for emitting electrons.

FIG. 7 is a diagram showing the measured luminescence intensity of a plurality of micro light-emitting devices, and FIG. 8 is a photograph of a plurality of measured micro light-emitting devices.

Referring to FIGS. 7 and 8 , the control unit may generate map data by collecting the light emission intensity (light image) of the plurality of micro light emitting devices 100 collected by the light detection unit. The control unit may determine that a defective element 101 that has a lower intensity than a predetermined light emission intensity or does not emit light is defective.

During the transfer process, only the normal devices 102 excluding the defective devices 101 can be selectively transferred. Additionally, when inspection is performed after transfer is completed, defective elements determined to be defective can be selectively removed or repaired.

Figure 9 is a conceptual diagram of an inspection device according to a second embodiment of the present invention, Figure 10 is a conceptual diagram of an inspection device according to a third embodiment of the present invention, Figure 11 is a diagram showing a filter array, and Figure 12 is a filter This is a diagram showing the state in which the array is rotating, and Figure 13 is a diagram showing the process of selecting wavelengths by a filter.

Referring to FIG. 9, the inspection device according to the embodiment can effectively accelerate the electron beam by arranging a plurality of electron beam guide units 300 in the vertical direction. At this time, the voltage level applied to the first electron beam guide 301 disposed at the bottom may be different from the voltage level applied to the second electron beam guide 302 disposed at the top. For example, the voltage level applied to the second electron beam guide 302 disposed at the top may be higher.

Additionally, a vibration unit 250 may be disposed in the electron beam irradiation unit 200 to provide vibration to the electron beam irradiation unit 200. Therefore, the direction of the emitted electron beam can be adjusted to improve the uniformity of the electron beam.

To increase uniformity, the electron beam guide 300 or stage 530 may be moved relatively. The moving member (not shown) moves the electron beam guide unit 300 or the stage 530 to the left and right, thereby exposing the hidden micro light emitting device 100 to the through hole of the electron beam guide unit 300 so that the electron beam is transmitted. It can be investigated.

The gate electrode of the electron beam irradiation unit 200 may be omitted. In this case, an electric field is formed between the first electrode layer 210 and the electron beam guide 300, and electrons may be emitted.

Referring to FIG. 10, the inspection device according to the embodiment can filter only the light in the desired wavelength range among the light emitted from the micro light emitting device 100. For example, if the desired peak wavelength band of the blue micro light emitting device 100 is 423 nm, blue light in other wavelength bands can be blocked using the filter array (PA1). Accordingly, the micro light emitting device 100 having a desired wavelength range can be selected.

Referring to FIGS. 11 and 12, the filter array PA1 is a first filter ( 810), and a second filter 820 that selectively transmits light in a second wavelength band different from the first wavelength band among the entire wavelength band of the first light, and a third filter that selectively transmits light in the third wavelength band. It may include (830). A plurality of filters 810, 820, and 830 may be selectively placed below the light detection unit 600 by the driving unit 840. The first light may be one of blue, green, and red wavelength bands.

Referring to FIG. 13, the blue micro light emitting device may emit light with a peak in the 440nm to 460nm wavelength range. A plurality of blue micro light-emitting devices are grown on one wafer, but the main peaks may be slightly different due to slightly different growth conditions. At this time, the emission wavelength band of each blue micro light emitting device 100 may have a band of approximately 5 nm. That is, the half width of the main peak of blue light emitted from each light emitting device may be very narrow.

For example, if 100 blue micro light emitting devices are manufactured, all of them emit blue light, but 32 may have a wavelength band of 440 nm to 445 nm, 38 may have a wavelength band of 446 nm to 450 nm, and the remaining 30 may have a wavelength band of 451 nm to 455 nm.

Therefore, when the transmission band CA1 of the first filter 810 is manufactured to be 440 nm to 445 nm, only blue micro light-emitting devices having a wavelength of 440 nm to 445 nm can be classified using the first filter 810. That is, a device having a wavelength range of 446 nm to 460 nm actually emits blue light, but since it is blocked by the first filter 810, it may be detected as not emitting light by the light detector 600.

When the transmission band CA2 of the second filter 820 is manufactured to be 446 nm to 450 nm, only the blue micro light emitting device 100 having a wavelength of 446 nm to 450 nm can be classified using the second filter 820.

In addition, if the transmission band (CA3) of the third filter 830 is manufactured to be 451 nm to 455 nm, only the blue micro light emitting devices 100 with a wavelength of 451 nm to 455 nm can be classified and inspected using the third filter 830. there is. However, the number of filters and the range of the transmission wavelength band can be freely modified.

Therefore, among the plurality of blue micro light emitting devices 100 grown on one wafer, devices having a desired blue wavelength can be classified in detail. Since the micro light emitting device 100 is used as a pixel of a display, it may be advantageous in terms of color uniformity to arrange devices with the same peak wavelength among blue wavelengths.

Additionally, after sorting the first to third blue micro light emitting devices 100, they can be evenly mixed and transferred to the panel. In this case, it can be advantageous in terms of color uniformity because the first blue micro light-emitting devices (or the second and third blue micro light-emitting devices) are not crowded in one part.

Above, the blue micro light emitting device was described as an example, but the green micro light emitting device and red micro light emitting device can also be classified in the same way.

Figure 14 is a conceptual diagram of an inspection device according to a fourth embodiment of the present invention, Figure 15 is a diagram showing a plurality of light emitting devices partially connected, and Figure 16 is a modified example of Figure 15.

Referring to Figures 14 and 15, the active layer 120 and the second conductive semiconductor layer 130 of the plurality of micro light emitting devices are separated from each other, but the first conductive semiconductor layer 110 may be connected to each other. This light-emitting structure may be a case where the production of light-emitting diodes has not yet been completed.

In this case, the electron beam passing through the electron beam guide 300 can be further accelerated by applying a positive voltage to the first conductive semiconductor layer 110 using the third power supply unit 430. At this time, if the electric field is sufficiently formed between the first conductive semiconductor layer 110 and the electron beam irradiation unit 200, the electron beam guide unit 300 may be omitted.

Referring to FIG. 16, the plurality of micro light emitting devices 100 may have been transferred to the display panel 20. Even when the transfer process of the plurality of micro light emitting devices 100 is completed, inspection of defective devices may be necessary before panel assembly is completed. The embodiment has the advantage of being able to conduct inspection even after transfer to the panel is completed because the micro light emitting device can emit light in a non-contact manner.

FIG. 17 is a conceptual diagram of an inspection device according to a fifth embodiment of the present invention, and FIGS. 18A and 18B are diagrams showing a process of scanning a line-shaped inspection area.

Referring to FIG. 17, the inspection device can perform inspection using the electron beam irradiation module 910. The electron beam irradiation module 910 may include a housing 930 that accommodates the electron beam irradiation unit 200 and the electron beam guide unit 300. The electron beam irradiation unit 200 and the electron beam guidance unit 300 may be large enough to irradiate the electron beam to only a partial area of the plurality of micro light emitting devices 100.

The housing 930 includes a transmission portion 920 that irradiates an electron beam only to a portion of the light emitting device and can be moved in one direction by the movement module 940. According to this configuration, the area of the electron beam irradiation unit 200 and the electron beam guidance unit 300 can be reduced, and inspection can be possible regardless of the size of the wafer.

Referring to FIGS. 18A and 18B, the electron beam irradiated from the electron beam irradiation module 910 may be irradiated in a line shape, and the irradiation areas SN1 and SN2 move in one direction in a line scan manner and continuously emit micro light emitting devices ( 100) can emit light. However, it is not necessarily limited to this, and the electron beam irradiated from the electron beam irradiation module 910 sequentially irradiates the 1 o'clock area, 5 o'clock area, 7 o'clock area, and 11 o'clock area of the substrate 10 in a clockwise or counterclockwise direction. You can also investigate.

Figure 19 is a conceptual diagram of an inspection device according to a sixth embodiment of the present invention.

Referring to FIG. 19 , the first electron beam irradiation module 910 and the second electron beam irradiation module 910 may be arranged at an angle based on a line perpendicular to the stage 530. The electron beam emitted from the first electron beam irradiation module 910 and the electron beam emitted from the second electron beam irradiation module 910 may be irradiated entirely to the plurality of micro light emitting devices 100. If the plurality of micro light emitting devices 100 can be irradiated as a whole by the first electron beam irradiation module 910, the second electron beam irradiation module 910 may be omitted.

According to this configuration, there is an advantage that the light detection unit 600 can directly capture light emitted by a plurality of light emitting devices. This structure may be suitable when the thickness of the substrate 10 is too thick and the intensity of light emitted from the light emitting device is low, or when the substrate 10 does not transmit light well, such as a display panel substrate or a GaAs substrate.

The first electron beam irradiation module 910 and/or the second electron beam irradiation module 910 may irradiate the electron beam only to some areas of the plurality of micro light emitting devices. At this time, the stage 530 can move in the horizontal direction. Accordingly, a plurality of micro light emitting devices 100 may sequentially emit light. Accordingly, the control unit 700 can sequentially detect defective devices by analyzing the optical image acquired by the photodetector 600. Alternatively, defective elements may be detected after overall scanning is completed.

FIG. 20 is a conceptual diagram of an inspection device according to a seventh embodiment of the present invention, FIG. 21 is a plan view of the electron beam guide unit, and FIG. 22 is a diagram showing a state in which the electron beam guide unit is moving.

20 and 21, the inspection device according to the embodiment includes a stage 530 on which a plurality of micro light-emitting devices 100 are arranged, and an electron beam irradiation unit 200 that irradiates an electron beam to the plurality of micro light-emitting devices 100. ), an electron beam guide unit 300 disposed in a partial area between the electron beam irradiation unit 200 and the plurality of micro light emitting devices 100, and a chamber 500 that forms a vacuum therein.

The electron beam guide unit 300 may include at least one through hole 310. In the embodiment, two rectangular-shaped through-holes 310 are illustrated, but the number of through-holes 310 may be one or three or more. Additionally, the shape of the through hole may be of various shapes (circle, polygon) rather than a rectangular shape.

The electron beam guiding unit 300 is disposed in a partial area between the electron beam irradiating unit 200 and the plurality of micro light emitting devices 100 and can be moved in one direction by the moving member 320.

Referring to FIG. 22, the electron beam guide unit 300 may be sequentially accelerated while moving in one direction by the moving member 320. According to this configuration, the electron beam can be relatively accelerated at a point where the electron beam guide unit 300 moves while the electron beam is emitted as a whole by the electron beam irradiation unit 200.

That is, since the electron beam irradiation unit 200 emits electron beams as a whole, some normal light emitting devices 100 can emit light. However, because the electron beam is not sufficiently accelerated, the luminescent image may be relatively dark. Alternatively, some normal light emitting devices 100 may not emit light because the electron beam is not effectively incident on them. These optical images may be treated as invalid.

At the point where the electron beam guide unit 300 is located, the electron beam is sufficiently accelerated and a relatively large number of electron beams are incident on the light emitting device, so that a relatively bright optical image can be detected. Accordingly, the electron beam guidance unit 300 moves and sequentially accelerates the electron beam, and a normal element can be detected by sequentially acquiring light emission images in the area where the electron beam is accelerated.

Figure 23 is a flowchart showing an inspection method according to an embodiment of the present invention, Figure 21a is a diagram showing a state in which the electron beam measurement unit measures the uniformity of the electron beam, and Figure 22b is a diagram showing the first electrode layer and the electron beam measurement unit being divided into a plurality of areas. This is a drawing showing the divided state.

Referring to Figures 1 and 23, the inspection method according to an embodiment of the present invention includes forming a vacuum inside the chamber 500 (S10), and micro light emitting device 100 disposed inside the chamber 500. irradiating an electron beam to (S20); Measuring the light emission intensity of the micro light emitting device 100 (S30); And it may include a step (S40) of determining whether the micro light emitting device 100 is defective.

In the step (S10) of forming a vacuum inside the chamber 500, when the micro light emitting device 100 is placed in the chamber 500, the vacuum pump is operated to control the vacuum inside the chamber 500 to 10 ^-5 Torr or less. You can. By adjusting the vacuum in the chamber 500 to 10 ^-5 Torr or less, scattering of the electron beam can be prevented from forming plasma.

In the step (S20) of irradiating an electron beam to the micro light-emitting device 100 disposed inside the chamber 500, a high voltage of 3000V to 5000V is pulse driven at 1 KHz or less in the electron beam irradiation unit 200, and the electron beam guidance unit 300 is pulsed. The electron beam can be accelerated by applying a positive voltage of 8000V to 12000V.

When an electron beam is irradiated to the micro light emitting device 100, the electron beam may collide in the active layer to generate an electron-hole pair. The generated electron-hole pairs may be confined to the well layer by the barrier layer of the active layer. The confined electrons and holes can emit visible light through recombination.

The intensity of visible light emitted from the micro light emitting device 100 may be proportional to the intensity (or density) of the electron beam. Accordingly, the intensity (or density) of the electron beam can be adjusted so that light emitted from the micro light emitting device 100 can be detected to determine whether it is defective.

In the step S30 of measuring the light emission intensity of the micro light emitting device 100, the light detector 600 may acquire an image in which the plurality of micro light emitting devices 100 emit light. The light detection unit 600 may be a camera, but is not necessarily limited thereto, and various detection equipment capable of detecting whether the micro light emitting device 100 emits light may be applied without limitation.

The optical detector 600 may convert the collected optical images into electrical signals and then transmit them to the control unit 700.

At this time, the filter 800 may be used to selectively transmit only light in a partial wavelength range among the first light emitted from the light emitting device. For detailed explanation of this, the contents described in FIGS. 10 to 13 may be applied as is.

The step (S40) of determining whether the micro light emitting device 100 is defective involves detecting light emitted from each micro light emitting device 100 and detecting the micro light emitting device 100 that emits light below a predetermined standard intensity as defective. It can be judged as follows.

According to the embodiment, between the step of forming a vacuum (S10) and the step of irradiating the electron beam (S20), measuring the electron beam intensity in a plurality of irradiation areas of the electron beam irradiation unit 200 disposed inside the chamber 500 ; And it may include adjusting the electron beam intensity of a radiation area that is outside a predetermined intensity range among the plurality of radiation areas.

Referring to FIGS. 24A and 24B , in the step of measuring the electron beam intensity, the electron beam measuring unit 30 may first measure the uniformity of the electron beam before irradiating the electron beam to the micro light emitting device 100. The electron beam measuring unit 30 is placed between the electron beam irradiating unit 200 and the stage 530 during measurement by a driving unit (not shown), and can be separated between the electron beam irradiating unit 200 and the stage 530 when the measurement is completed. You can.

The electron beam measuring unit 30 may be divided into a plurality of detection areas (P1 to P24). The plurality of sensing areas (P1 to P24) may be arranged to match the plurality of irradiation areas (S1 to S24). Therefore, it is possible to determine in which irradiation area the electron beam is non-uniform using the values measured in the plurality of detection areas (P1 to P24).

In the step of adjusting the electron beam intensity, a point where the electron beam intensity is relatively uneven can be detected and the electron beam intensity in the corresponding area can be adjusted to match a predetermined reference range (or average intensity).

For example, a point where the electron beam intensity is weak can increase the voltage level of the irradiation area, and a point where the electron beam intensity is strong can lower the voltage level of the irradiation area.

Although the above description focuses on the examples, this is only an example and does not limit the present invention, and those skilled in the art will be able to You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

Claims (20)

A stage on which a plurality of micro light emitting devices are arranged;
an electron beam irradiation unit that radiates electron beams to the plurality of micro light emitting devices;
a light detection unit that acquires an image of light emitted from the plurality of micro light emitting devices;
an electron beam guiding unit disposed between the electron beam irradiation unit and the plurality of micro light emitting devices; and
An inspection device comprising a control unit that determines whether the plurality of micro light emitting devices are defective based on the optical image acquired by the light detection unit. According to paragraph 1,
The electron beam guide part includes at least one through hole through which the electron beam passes. According to paragraph 2,
An inspection device wherein the electron beam guide part has a mesh shape. According to paragraph 2,
An inspection device in which at least one through hole of the electron beam guide part extends long. According to paragraph 2,
The electron beam guide has an area corresponding to a partial area of the stage,
An inspection device in which the electron beam guidance unit moves in one direction between the stage and the electron beam irradiation unit. According to paragraph 1,
The ratio of the first distance between the electron beam irradiation unit and the micro light emitting element and the second distance between the electron beam irradiation unit and the electron beam guide unit (first distance: second distance) is 1: 0.6 to 1: 0.99, the inspection device . According to paragraph 1,
The electron beam guide unit,
A first electron beam guiding unit disposed between the electron beam irradiation unit and a plurality of micro light emitting elements, and
An inspection device comprising a second electron beam guide disposed between the first electron beam guide and the plurality of micro light emitting devices. According to paragraph 1,
The electron beam irradiation unit includes an electrode layer, a plurality of emitters formed on the electrode layer to emit electrons toward the plurality of micro light-emitting devices, and a gate electrode spaced apart from the electrode layer,
The emitter is an inspection device including a carbon nanotube. According to clause 8,
An inspection device wherein the voltage level applied to the electron beam guide is higher than the voltage level applied to the gate electrode. According to paragraph 1,
The plurality of micro light emitting devices include a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer,
The first conductivity type semiconductor layer, the active layer, and the second conductivity type semiconductor layer each emit light when irradiated with an electron beam. According to clause 10,
It includes a filter that partially blocks light incident on the light detection unit,
The filter transmits the first light emitted from the active layer and blocks the second light emitted from the first conductivity type semiconductor layer or the second conductivity type semiconductor layer. According to clause 10,
It includes a filter array that partially blocks light incident on the light detection unit,
The filter array includes a first filter that selectively transmits light in a first wavelength band among the entire wavelength band of the first light emitted from the active layer of the plurality of micro light emitting devices, and a first filter that selectively transmits light in a first wavelength band among the entire wavelength band of the first light. It includes a second filter that selectively transmits light in a second wavelength band different from the band,
The first light is one of blue light, green light, and red light. According to clause 12,
The filter array includes a driving unit that selectively disposes the first filter and the second filter on the light detection unit. According to paragraph 1,
An inspection device comprising a vibration unit that applies vibration to the electron beam irradiation unit. According to paragraph 2,
An inspection device in which the stage or the electron beam guide moves in one direction, so that the micro light emitting device overlapping with the electron beam guide is exposed through a through hole of the electron beam guide. According to paragraph 1,
a chamber in which the stage, the electron beam irradiation unit, and the electron beam guidance unit are disposed; and
An inspection device comprising a vacuum pump that creates a vacuum inside the chamber. According to paragraph 1,
a housing accommodating the electron beam irradiation unit and the electron beam guidance unit; and
It includes a movement module that moves the housing,
An inspection device wherein the electron beam emitted from the housing is irradiated only to a portion of the plurality of micro light-emitting devices, and the irradiation area of the electron beam is moved in one direction by the movement module. According to clause 17,
The housing is disposed at an angle based on an imaginary line perpendicular to the stage. forming a vacuum inside the chamber;
irradiating an electron beam to a plurality of micro light emitting devices disposed inside the chamber;
Measuring the light emission intensity of the plurality of micro light emitting devices; and
Comprising the step of determining whether the plurality of micro light emitting devices are defective,
An inspection method in which the electron beam is accelerated by an electron beam guider disposed between the electron beam irradiation unit and the plurality of micro light-emitting devices and is injected into the plurality of micro light-emitting devices. According to clause 19,
The step of measuring the luminescence intensity is,
An inspection method for selectively transmitting light in a partial wavelength band among the entire wavelength band of the first light emitted from the active layer of the plurality of micro light emitting devices.