KR20240022671A - 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; and a chamber in which the stage and the electron beam irradiator are accommodated and a vacuum is formed therein.

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 non-contactly inspect whether a micro light emitting device is defective.

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 a large number of these micro light emitting devices are manufactured on a single wafer, it is important to accurately inspect the light emitting devices for defects.

Methods for inspecting a micro light emitting device can be divided into a contact method in which light is emitted by contacting the micro light emitting device, and a non-contact method in which light is emitted without contacting the light emitting device.

A conventional non-contact inspection device places the micro light emitting device 100 and the field plate 11 apart as shown in Figure 1 and applies a voltage to form an electric field, thereby injecting capacitive current into the micro light emitting device 100 to emit light. It is a structure.

However, if the gaps G1 and G2 between the micro light emitting devices 100 and the field plate 11 are not constant, the capacitive current level may vary and only some micro light emitting devices may emit light. Therefore, there is a problem in which accurate testing becomes difficult.

The embodiment provides an inspection device that emits light from a micro light emitting device by irradiating an electron beam.

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; and a chamber in which the stage and the electron beam irradiation unit are accommodated and a vacuum is formed therein.

a light detection unit that detects light emitted from the plurality of micro light emitting devices; and a control unit that determines whether the device is defective using light emission information of the plurality of micro light emitting elements detected by the light detection unit.

The electron beam irradiation unit may include a first electrode layer and a plurality of emitters formed on the first electrode layer to emit electron beams toward the plurality of micro light emitting devices.

The plurality of emitters may include carbon nanotubes.

It may include a voltage regulator that adjusts the voltage applied to the electron beam irradiation unit.

The plurality of micro light emitting devices include a first conductivity type semiconductor layer disposed on a substrate, an active layer disposed on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer. a layer, wherein the active layer and the second conductive semiconductor layer of the plurality of micro light emitting devices are divided into a plurality of layers, the first conductive semiconductor layer of the plurality of micro light emitting devices are connected to each other, and the voltage control The unit may apply voltage to the first electrode layer and the first conductive semiconductor layer.

The voltage regulator may apply a voltage to the first electrode layer and a second electrode layer disposed below the plurality of micro light emitting devices.

It may include an electron beam measurement unit that measures the intensity of the electron beam radiated from the electron beam irradiation unit.

The electron beam irradiation unit includes a plurality of irradiation areas, the electron beam measurement unit includes a plurality of detection areas corresponding to the plurality of irradiation areas, and the control unit determines the intensity of the electron beam detected in some of the detection areas within a predetermined reference range. If it deviates, the electron beam irradiation intensity of the irradiation area corresponding to the partial detection area can be adjusted.

The light detection unit may detect light generated from the plurality of micro light emitting devices and emitted from the bottom of the stage.

The light detection unit may detect light generated from the plurality of micro light emitting devices and emitted to the top of the electron beam irradiation unit.

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.

In the step of irradiating the electron beam, the micro light emitting device may emit light by irradiating the electron beam from an electron beam irradiation unit disposed inside the chamber.

Between forming the vacuum and irradiating the electron beam, measuring electron beam intensity in a plurality of irradiation areas of the electron beam irradiation unit disposed inside the chamber; 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.

According to an embodiment, there is an advantage in that a plurality of micro light emitting devices can be inspected by uniformly emitting light by providing an inspection device that emits light from the micro light emitting devices by irradiating an electron beam.

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 a conventional inspection device,
Figure 2 is a conceptual diagram of an inspection device according to the first embodiment of the present invention;
Figure 3 is a diagram showing the process of irradiating an electron beam to a plurality of micro light-emitting devices;
Figure 4 is a diagram showing the principle by which a light-emitting device emits light by an electron beam;
Figure 5 is a first modified example of Figure 3,
Figure 6 is a second modification of Figure 3,
Figures 7a to 7e are diagrams showing various types of emitters;
Figure 8a is a diagram showing a state in which the electron beam measuring unit measures the uniformity of the electron beam;
Figure 8b 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;
Figure 9 is a diagram showing the measured luminous intensity of a plurality of micro light-emitting devices;
Figure 10 is a conceptual diagram of an inspection device according to a second embodiment of the present invention;
11 is a conceptual diagram of an inspection device according to a third embodiment of the present invention;
Figure 12 is a conceptual diagram of another inspection device according to the fourth embodiment of the present invention;
Figure 13 is a diagram showing the state in which the adhesive layer of the pickup device is attached to a plurality of micro light-emitting elements;
Figure 14 is a diagram showing the process of transferring and then inspecting a plurality of micro light-emitting devices with a pickup device;
Figure 15 is a modified example of Figure 14,
Figure 16 is a diagram showing the process of transferring a plurality of micro light-emitting elements transferred to the pickup device to another substrate;
Figure 17 is a flowchart showing an inspection method according to an embodiment of the present invention.

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.

Figure 2 is a conceptual diagram of an inspection device according to the first embodiment of the present invention, Figure 3 is a diagram showing the process of irradiating an electron beam to a plurality of micro light-emitting devices, and Figure 4 is a diagram showing the principle of a light-emitting device emitting light by an electron beam. This is a drawing that shows.

2 and 3, the inspection device according to the embodiment includes a stage 300 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. , and a chamber 500 in which the stage 300 and the electron beam irradiation unit 200 are accommodated and a vacuum is formed therein.

The chamber 500 accommodates the stage 300 and the electron beam irradiation unit 200, 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 thereto and can be adjusted to satisfy various conditions for irradiating an electron beam to a micro light-emitting device.

The micro light emitting device 100 may be a 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 30㎛ to 60㎛, but it is not necessarily limited thereto, and light emitting devices of various sizes may be applied. Additionally, in addition to the micro light emitting device 100, mini light emitting devices of 200㎛ to 500㎛ may also be applied.

The micro light emitting device 100 may be mesa etched (H1) to divide the active layer 130 and the second conductive semiconductor layer 140 into a plurality of layers, but the first conductive semiconductor layer 120 may be connected to each other. there is. However, it is not necessarily limited to this, and the first conductive semiconductor layer 120 may also be completely separated.

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. Epi-growth can be performed on the substrate 110 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 under the first electrode layer 210 to emit electron beams toward the plurality of micro light emitting devices 100. there is.

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 first electrode layer 210 may be a cathode.

The emitter 220 may include, but is not necessarily limited to, carbon nanotubes (CNTs). An electron beam can be generated by an electric field applied to carbon nanotubes.

The plurality of carbon nanotubes constituting the emitter 220 may have a shape extending from the first electrode layer 210 in a first direction (vertical direction) toward the stage 300. However, it is not necessarily limited to this, and the plurality of carbon nanotubes may have a shape extending in a second direction (horizontal direction) perpendicular to the first direction.

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

The voltage regulator 400 may apply a voltage to the first electrode layer 210 and the first conductive semiconductor layer 120 of the micro light emitting device 100. The first electrode layer 210 may serve as a cathode, and the first conductive semiconductor layer 120 may serve as an anode.

The voltage regulator 400 can pulse-drive a high voltage of 3000V to 5000V at 1 KHz or less. When a high voltage pulse is applied, an electric field may be formed between the first electrode layer 210 and the micro light emitting device 100. Accordingly, the electron beam emitted from the emitter 220 can be effectively irradiated to the micro light emitting device 100.

The light detection unit 600 can capture images or videos emitted by the plurality of micro light emitting devices 100. 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 light detection unit 600 may analyze the collected light emission intensity (spectrum) or wavelength, convert it into an electrical signal, and then transmit the electrical signal to the control unit 700.

The control unit 700 is a processor that controls the overall inspection device. The control unit 700 controls the operations of the electron beam irradiation unit 200 and the voltage regulator 400, receives the measurement results of the light detection unit 600, and outputs map data including the evaluation results of the micro light emitting device 100. can do.

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.

Each micro light emitting device 100 may include a first conductivity type semiconductor layer 120, an active layer 130, and a second conductivity type semiconductor layer 140. The first conductivity type semiconductor layer 120 may be implemented with a compound semiconductor such as group III-V or group II-VI, and the first conductivity type semiconductor layer 120 may be doped with a first dopant.

The first conductive semiconductor layer 120 is a semiconductor material, InAlGaN, with a composition formula of Al _x In _y Ga _(1-xy) N (0≤x≤1, 0≤y≤1, 0≤x+y≤1) , AlGaAs, GaP, GaAs, GaAsP, or 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 120 may be an n-type nitride semiconductor layer.

The active layer 130 may be disposed on the first conductive semiconductor layer 120. Additionally, the active layer 130 may be disposed between the first conductive semiconductor layer 120 and the second conductive semiconductor layer 140.

The active layer 130 is a layer where electrons (or holes) injected through the first conductive semiconductor layer 120 and holes (or electrons) injected through the second conductive semiconductor layer 140 meet. The active layer 130 transitions to a low energy level as electrons and holes recombine, and can generate light with a corresponding wavelength.

The active layer 130 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. The structure is not limited to this. The active layer 130 can generate light in the visible light wavelength range.

The second conductive semiconductor layer 140 may be disposed on the active layer 130. The second conductivity type semiconductor layer 140 may be implemented with a compound semiconductor such as group III-V or group II-VI, and the second conductivity type semiconductor layer 140 may be doped with a second dopant.

The second conductive semiconductor layer 140 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 may be formed of a selected material. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second conductive semiconductor layer 140 doped with the second dopant may be a p-type semiconductor layer.

Referring to FIG. 4, when an electron beam (E) is irradiated to a micro light emitting device, the electron beam collides 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. Bound electrons and holes can emit visible light through recombination.

The intensity of visible light emitted from a micro light emitting device 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 can be detected to determine whether it is defective.

The micro light emitting device may include a blue light emitting device, a green light emitting device, and a red light emitting device. Therefore, the micro light emitting device can emit light in blue, green, or red wavelength ranges. Additionally, in the case of a micro light emitting device that has been transferred to a panel substrate, light in blue, green, and red wavelength bands may be detected simultaneously.

According to the embodiment, since it is a cathodoluminescence (CL) method in which micro light emitting devices emit light by irradiating an electron beam, there is an advantage in that a plurality of micro light emitting devices 100 can emit light uniformly compared to other non-contact light emitting methods.

Scanning Electron 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, allowing for complex surface structures and crystal appearances. It is an analysis equipment that can observe three-dimensional shapes at high magnification.

A scanning electron microscope consists of an electron gun that generates and accelerates an electron beam, a focusing lens and objective lens that narrowly collects the electron beam, and a deflection coil that controls the path of the electron beam until the electrons that leave the filament reach the specimen. Consists of.

However, the scanning electron 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 a field emission emitter array, which is a cold cathode electron source, in a matrix form and emits cathodic light by irradiating electron beams to a phosphor. However, the emitter of the field emission display is generally made of ultra-small electronic tips (Micro tips) and is different from the present embodiment in that it is not made of carbon nanotubes. Additionally, the required electron beam uniformity is lower than that of this embodiment.

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 field-emitted electrons are accelerated by an electric field. The difference is that energy is obtained and then injected into the LED to generate light.

FIG. 5 is a first modified example of FIG. 3, and FIG. 6 is a second modified example of FIG. 3.

Referring to FIG. 5, the light emitting structure may be isolated to manufacture a plurality of micro light emitting devices 100 and then inspected for defects. According to the embodiment, the first conductive semiconductor layer 120 of each micro light emitting device 100 is also completely separated by mesa etching (H2), so the voltage regulator 400 is separated from the first electrode layer 210 and a plurality of micro It may be connected to a separate second electrode layer (not shown) disposed below the light emitting device 100.

If the stage 300 is made of a conductive material, the voltage regulator 400 may be connected to the first electrode layer 210 and the stage 300 to form an electric field.

The first light detection unit 610 disposed on top of the electron beam irradiation unit 200 can detect light emitted from the top of the active layer 130 and passing through the electron beam irradiation unit 200. If the first electrode layer 210 is made of a light-transmitting electrode such as ITO and the electron beam irradiation unit 200 has sufficient light transparency, the first photodetector 610 can effectively measure the light emission intensity of the micro light-emitting device 100. .

The second light detection unit 620 disposed below the stage 300 may detect light emitted from the bottom of the active layer 130 and passing through the stage 300. When the stage 300 is made of a light-transmitting material, the second light detector 620 can effectively measure the light emission intensity of the micro light-emitting device 100.

In the embodiment, it is illustrated that the first light detection unit 610 and the second light detection unit 620 are provided at the same time, but this is not necessarily limited, and only one of the first light detection unit 610 or the second light detection unit 620 is used. It may also be provided.

Referring to FIG. 6, inspection may be performed even before the light emitting structure is separated into a plurality of micro light emitting devices. Even if a non-emission area (T1) is formed due to a defect in a part of the light emitting structure, the remaining area can be tested for light emission.

That is, according to the embodiment, only a portion of the light emitting structure is mesa-etched (see FIG. 3), a plurality of light emitting devices are manufactured by isolation (see FIG. 5), or the light emitting structure is not separated (see FIG. 6). (Reference) can also be inspected. In addition, inspection is possible even after the micro light emitting device is separated from the substrate and transferred.

Figures 7A to 7E are diagrams showing various types of emitters.

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

Referring to FIG. 7A, the first electrode layer 210 is disposed on the substrate 230, and the emitter 220 has a sharp end so that it can easily emit electrons. At this time, only the end portion of the emitter 220 may be exposed to the outside by the insulating layer 241 and the gate 242. Referring to FIG. 7B, the emitter 220 may have an area that becomes sharper toward the top.

Referring to FIG. 7C, the emitter 220 may be arranged in the horizontal direction to emit electrons. At this time, the emitted electrons may be bent and emitted in a vertical direction. Referring to FIG. 7D, when voltage is applied to the 1-1 electrode layer 210a and the 1-2 electrode layer 210b, light is emitted from the first emitter 220-1 formed in the 1-1 electrode layer 210a. It may be irradiated and reflected by the second emitter 220-2. Referring to FIG. 7E, electrons emitted from the emitter 220 may be emitted laterally and collide with the block 243, thereby changing the direction of travel.

FIG. 8A is a diagram showing a state in which the electron beam measuring unit measures the uniformity of the electron beam, and FIG. 8B 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.

Referring to FIGS. 8A and 8B , the electron beam measuring unit 910 is disposed between the electron beam irradiating unit 200 and the stage 300 to measure the uniformity of the electron beam. As described above, uniform light emission can be achieved only when a uniform electron beam is irradiated to the plurality of micro light emitting devices 100. If the intensity of the electron beam is weakened in some areas, there is a problem that it may be judged to be defective even though it is a normal light emitting device.

Since the method of inspecting by irradiating an electron beam is an indirect measurement method, the intensity of light emission may be relatively weak compared to the method of emitting light by directly applying current. Therefore, if the intensity of the electron beam is not uniform, it may be determined that some light emitting devices do not emit light. Therefore, accurate testing may become difficult.

According to the embodiment, the electron beam irradiation unit 200 may be divided into a plurality of irradiation areas (S1 to S24). The voltage level of each irradiation area may be individually adjusted by the voltage adjustment unit 400. The number of irradiation areas (S1 to S24) is shown to be 24, but this is not necessarily limited, and the number of irradiation areas can be adjusted in various ways.

The electron beam measuring unit 910 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). When the plurality of irradiation areas (S1 to S24) are divided into 24, the plurality of sensing areas (P1 to P24) may also be divided into the same number.

According to one embodiment, before irradiating an electron beam to the micro light emitting device 100, the electron beam measuring unit 910 first measures the uniformity of the electron beam, detects a point where the electron beam intensity is relatively uneven, and detects the electron beam intensity in the corresponding area. (or density) can be adjusted to match a predetermined reference range (or average intensity).

The electron beam measuring unit 910 is placed at the lower part of the electron beam irradiating unit 200 during measurement by a driving unit (not shown), and can be removed from the lower part of the electron beam irradiating unit 200 when measurement is completed.

For example, the tenth irradiation area S10 disposed in the center may have relatively strong intensity due to the addition of a portion of the electron beam irradiated from the neighboring irradiation areas S4, S9, S16, and S11. In contrast, since the first sensing area S1 disposed at the edge has fewer adjacent irradiation areas S2 and S7, the amount of added electron beam is small, so the intensity may be relatively weak. Accordingly, the intensity of the electron beam measured in the first detection area P1 may be weaker than the intensity of the electron beam measured in the tenth detection area P10.

In this case, the controller may control the voltage regulator 400 to increase the voltage level of the first irradiation area S1 compared to the 10th irradiation area S10. Therefore, the intensity of the electron beam in the central area and the intensity of the electron beam in the edge area can be uniformly controlled.

Alternatively, if the test result determines that the intensity of the ninth detection area (P9) is stronger than the predetermined reference range (or average intensity), the voltage level of the ninth irradiation area (S9) is lowered to the predetermined reference range (or average intensity). It can also be adjusted closely. Additionally, if the intensity of the tenth sensing area (P10) is determined to be weak, the voltage level of the tenth irradiation area (S10) may be increased to adjust it to be close to a predetermined reference range (or average intensity). Through this adjustment, the uniformity of the electron beam irradiated from the electron beam irradiation unit 200 can be adjusted to a constant level.

Figure 9 is a diagram showing the measured light emission intensity of a plurality of micro light emitting devices.

Referring to FIG. 9, the control unit may generate map data by collecting the light emission intensity of the plurality of micro light emitting devices 100 collected by the camera. The control unit may determine that the micro light emitting device 101 has a lower intensity than a predetermined light emission intensity or does not emit light as defective.

During the transfer process, only the normal micro light emitting devices 100, excluding the micro light emitting devices 101 determined to be defective, can be selectively transferred. Additionally, when inspected after the transfer is completed, the micro light emitting device 101 determined to be defective can be selectively removed.

FIG. 10 is a conceptual diagram of an inspection device according to a second embodiment of the present invention, and FIG. 11 is a conceptual diagram of an inspection device according to a third embodiment of the present invention.

Referring to FIG. 10, the chamber 500 includes a first door 510 through which the micro light emitting device 100 can enter, a second door 520 through which the tested micro light emitting device 100 can be discharged, and a vacuum pump 530 that creates a vacuum. According to this configuration, the micro light emitting device 100 can be continuously introduced and discharged by the robot arm or conveyor belt, thereby enabling continuous inspection.

In addition to the first electrode layer 210 and the emitter 220, the electron beam irradiation unit 200 further includes a body 250 on which the first electrode layer 210 is disposed, and a first driving unit 260 that raises and lowers the body 250. can do. According to this configuration, when the micro light emitting device 100 is seated on the stage 300, the electron beam irradiation unit 200 can descend.

Since the distance between the stage 300 and the electron beam irradiation unit 200 is optimally adjusted, there is an advantage in that the electron beam can be irradiated uniformly. However, it is not necessarily limited to this, and a second driving unit 310 that raises and lowers the stage 300 may be disposed.

That is, the electron beam irradiation unit 200 may be raised and lowered by the first driving unit 260, and the stage 300 may be raised and lowered by the second driving unit 310. Additionally, the electron beam irradiation unit 200 and the stage 300 may be raised and lowered together by the first driving unit 260 and the second driving unit 310.

The first light detection unit 610 may be disposed inside the body 250 of the electron beam irradiation unit 200. If the first electrode layer 210 and the emitter 220 are sufficiently transparent, the first light detector 610 can effectively detect light emitted upward from the micro light emitting device 100.

The second light detection unit 620 may be disposed below the stage 300. If the stage 300 is sufficiently transparent, the second light detection unit 620 can effectively detect light emitted downward from the micro light emitting device 100.

In the embodiment, it is illustrated that the first light detection unit 610 and the second light detection unit 620 are provided at the same time, but this is not necessarily limited, and only one of the first light detection unit 610 or the second light detection unit 620 is used. It may also be provided.

Referring to FIG. 11, the inspection device may include a structure for scanning the micro light emitting device 100. The electron beam irradiation unit 200 irradiates an electron beam to a partial area of the micro light emitting device 100, and the light detection unit 600 can detect the light emission intensity of the micro light emitting device 100 in the corresponding area. Additionally, the electron beam irradiation unit 200 and the light detection unit 600 may inspect a plurality of micro light emitting devices 100 while moving in one direction D1.

According to this structure, the size of the electron beam irradiation unit can be manufactured small, and inspection is possible regardless of the size of the micro light emitting device.

Figure 12 is a conceptual diagram of another inspection device according to the fourth embodiment of the present invention, Figure 13 is a diagram showing the state in which the adhesive layer of the pickup device is attached to a plurality of micro light-emitting devices, and Figure 14 is a diagram showing a state in which the adhesive layer of the pickup device is attached to a plurality of micro light-emitting devices. This is a diagram showing the process of inspecting a light emitting device after transferring it. FIG. 15 is a modified example of FIG. 14, and FIG. 16 is a diagram showing the process of transferring a plurality of micro light emitting devices transferred to a pickup device to another substrate.

Referring to FIG. 12, a process of transferring the micro light emitting device 100 to the panel substrate is essential. The transfer process can be defined as the operation of separating the micro light emitting device 100 from the growth substrate 110 and transferring it to the panel substrate.

The transfer technology may include a transfer technology using static electricity, a transfer technology using LLO (Laser-Lift-Off), and a transfer technology using adhesive tape.

As an example, a technique using an adhesive tape may separate the micro light emitting device 100 from the growth substrate 110 using the adhesive layer 820 formed on the header 800.

Referring to FIG. 13, the header 800 is lowered so that the adhesive layer 820 can be attached to the micro light emitting device 100. Thereafter, when the header 800 is raised by the lifting unit 830 as shown in FIG. 14, the micro light emitting device 100 may be separated from the substrate 110 and transferred to the adhesive layer 820.

At this time, the bonding force between the substrate 110 and the micro light emitting device 100 can be adjusted to be weaker than the bonding force between the adhesive layer 820 and the micro light emitting device 100. For example, the substrate 110 may be etched to partially remove the contact surface between the substrate 110 and the micro light emitting device 100, thereby reducing the bonding force between the substrate 110 and the micro light emitting device 100.

An electron beam irradiation unit 200 and a light detection unit 600 may be disposed in the header 800. If the transfer process is carried out in a vacuum, the electron beam emitted from the electron beam irradiation unit 200 may pass through the adhesive layer 820 and be irradiated to the plurality of micro light emitting devices 100. Additionally, if the adhesive layer 820 and the electron beam irradiation unit 200 are sufficiently transparent, the light detection unit 600 can detect light emitted from the plurality of micro light emitting devices 100.

According to this configuration, inspection may be possible in the process of transferring the micro light emitting device 100 without being equipped with a separate inspection device. This inspection system may be more effective in the case of the electrostatic method or LLO method that can selectively transfer the micro light emitting device 100. For example, the header 800 may be placed on the micro light emitting device 100 to inspect for defects using the above inspection method, and then only normal light emitting devices may be selectively transferred.

Referring to FIG. 15 , the light detection unit 600 may be placed below the header 800. Therefore, when the micro light emitting device 100 emits light by the electron beam irradiation unit 200 disposed within the header 800, the light detection unit 600 disposed below the header 800 can effectively measure the light emission intensity. there is.

Referring to FIG. 16, the header 800 can be moved to the transfer substrate 920 to transfer a plurality of micro light emitting devices 100. For example, if UV or heat is applied to the adhesive layer 830 of the header 800, the adhesive layer 830 may lose its viscosity. Accordingly, the plurality of micro light emitting devices 820 can be transferred to the transfer substrate 920. The transfer substrate 920 may be a display panel substrate or a separate adhesive substrate.

Figure 17 is a flowchart showing an inspection method according to an embodiment of the present invention.

Referring to Figures 2 and 17, 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.

The step (S20) of irradiating an electron beam to the micro light emitting device 100 disposed inside the chamber 500 is performed by pulse driving a high voltage of 3000V to 5000V at 1 KHz or less between the electron beam irradiation unit 200 and the micro light emitting device 100. can do.

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. Bound electrons and holes can emit visible light through recombination.

The intensity of visible light emitted from a micro light emitting device 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 can be detected to determine whether it is defective.

In the step S30 of measuring the light emission intensity of the micro light emitting devices 100, the light detector 600 may capture images or videos 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 light detection unit 600 may analyze the collected light emission intensity or wavelength, convert it into an electrical signal, and then transmit the electrical signal to the control unit 700.

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 an embodiment, between the step of forming a vacuum (S10) and the step of irradiating an electron beam (S20), measuring the electron beam intensity in a plurality of irradiation areas of the electron beam irradiation unit disposed inside the chamber; 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. 8A and 8B , in the step of measuring the electron beam intensity, the electron beam measuring unit 910 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 910 is placed at the lower part of the electron beam irradiating unit 200 during measurement by a driving unit (not shown), and can be removed from the lower part of the electron beam irradiating unit 200 when measurement is completed.

The electron beam measuring unit 910 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 may increase the voltage level of the irradiation area, and a point where the electron beam intensity is strong may 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 (14)

A stage on which a plurality of micro light-emitting devices are arranged;
An electron beam irradiation unit that irradiates electron beams to the plurality of micro light emitting devices; and
An inspection device comprising a chamber that accommodates the stage and the electron beam irradiation unit and forms a vacuum therein.
According to paragraph 1,
a light detection unit that detects light emitted from the plurality of micro light emitting devices; and
An inspection device including a control unit that determines whether a defect exists using light emission information of the plurality of micro light-emitting devices detected by the light detection unit.
According to paragraph 2,
The electron beam irradiation unit includes a first electrode layer and a plurality of emitters formed on the first electrode layer to emit electron beams toward the plurality of micro light-emitting devices.
According to paragraph 3,
An inspection device wherein the plurality of emitters include carbon nanotubes.
According to paragraph 3,
An inspection device including a voltage regulator that adjusts the voltage applied to the electron beam irradiation unit.
According to clause 5,
The plurality of micro light emitting devices include a first conductivity type semiconductor layer disposed on a substrate, an active layer disposed on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer. Contains layers,
The active layer and the second conductivity type semiconductor layer of the plurality of micro light emitting devices are divided into a plurality, and the first conductivity type semiconductor layers of the plurality of micro light emitting devices are connected to each other,
The voltage regulator is an inspection device that applies a voltage to the first electrode layer and the first conductive semiconductor layer.
According to clause 5,
The voltage regulator is an inspection device that applies voltage to the first electrode layer and the second electrode layer disposed below the plurality of micro light emitting devices.
According to clause 5,
An inspection device including an electron beam measurement unit that measures the intensity of the electron beam radiated from the electron beam irradiation unit.
According to clause 8,
The electron beam irradiation unit includes a plurality of irradiation areas,
The electron beam measuring unit includes a plurality of detection areas corresponding to the plurality of irradiation areas,
The control unit is an inspection device that adjusts the electron beam irradiation intensity of the irradiation area corresponding to the partial detection area when the intensity of the electron beam detected in the partial detection area deviates from a predetermined reference range.
According to paragraph 2,
An inspection device wherein the light detection unit detects light generated from the plurality of micro light emitting devices and emitted from the bottom of the stage.
According to paragraph 2,
An inspection device wherein the light detection unit detects light generated from the plurality of micro light-emitting devices and emitted from an upper portion of the electron beam irradiation unit.
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
An inspection method comprising determining whether the plurality of micro light emitting devices are defective.
According to clause 12,
The step of irradiating the electron beam is,
An inspection method in which the micro light emitting device emits light by irradiating an electron beam from an electron beam irradiation unit disposed inside the chamber.
According to clause 12,
Between forming the vacuum and irradiating the electron beam,
Measuring the electron beam intensity in a plurality of irradiation areas of the electron beam irradiation unit disposed inside the chamber; and
An inspection method comprising adjusting the electron beam intensity of an irradiation area that is outside a predetermined intensity range among the plurality of irradiation areas.