Separation system of light emitting diode device and separation method of light emitting diode device

Abstract

Disclosed are a system for separating a light-emitting diode device and a method for separating a light-emitting diode device, which can efficiently separate a light-emitting diode device from a substrate using a high-frequency ultrasonic wave and a light-emitting diode device that is hydrophobically treated using a low-molecular-weight modification compound. The system for separating a light emitting diode device using a hydrophobically modified light emitting diode device according to the present invention comprises: a first housing part for housing a substrate on which a plurality of light emitting diode devices are formed and an organic solvent; the second accommodating part is arranged outside the first accommodating part and is used for accommodating the first accommodating part and the fluid; a plurality of ultrasonic wave generating parts which are arranged at the lower part of the second accommodating part and are used for applying ultrasonic waves to the substrate; and a channel part which is connected to the second housing part and circulates a fluid. The plurality of light-emitting diode devices include, on the surfaces thereof, a compound for modification including a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

Description

Technical Field

[0001] The present invention relates to a light-emitting diode device separation system and a light-emitting diode device separation method that can effectively separate a light-emitting diode device from a substrate by using a light-emitting diode device surface-treated with a low molecular weight modifying compound and high-frequency ultrasonic waves. Background Art

[0002] Light-emitting devices can be manufactured by an epitaxial growth method in which a semiconductor crystal is grown on a wafer substrate.

[0003] After growing a plurality of semiconductor layers on the wafer substrate, a light-emitting device can be manufactured by separating it from the wafer substrate. In this case, the process of separating the light-emitting device can use a method of separating the semiconductor layer grown on the substrate by applying a mechanical force.

[0004] However, the process using mechanical force is achieved by direct manual operation of an operator, so it has problems such as a long required process time, uneven and easily damaged cutting surfaces of the separated light-emitting devices.

[0005] On the other hand, a method of separating a light-emitting device from a substrate using a device called a laser lift-off machine is also used, but it is difficult to capture all the separated light-emitting devices, so it has a disadvantage of low separation yield.

[0006] Therefore, a technology capable of effectively separating a light-emitting device from a substrate is needed. Summary of the Invention

[0007] Technical Problem

[0008] An object of the present invention is to provide a light-emitting diode device separation system that can improve the aggregation phenomenon of light-emitting diode devices that occurs during the separation process.

[0009] Moreover, an object of the present invention is to provide a light-emitting diode device separation system that can improve the yield of light-emitting diode devices separated from a substrate.

[0010] Moreover, an object of the present invention is to provide a light-emitting diode device separation method as follows: separating a light-emitting diode device in which hydrophobic modification is caused by high-frequency ultrasonic waves in an organic solvent, so that there is no external loss, and the uniformity of the length of the light-emitting diode device can also be improved.

[0011] The object of the present invention is not limited to the objects mentioned above, and other objects and advantages of the present invention not mentioned can be understood through the following description and can be more clearly understood through the embodiments of the present invention. And it is obvious that the objects and advantages of the present invention can be achieved by the means shown in the claims of the invention and their combinations.

[0012] Technical solution

[0013] The separation system of a light-emitting diode device using a hydrophobically modified light-emitting diode device according to the first embodiment of the present invention is characterized in that it includes: a first accommodating part for accommodating a substrate formed with a plurality of light-emitting diode devices and an organic solvent; a second accommodating part disposed outside the first accommodating part for accommodating the first accommodating part and a fluid; a plurality of ultrasonic generating parts disposed at the lower part of the second accommodating part for applying ultrasonic waves to the substrate; and a channel part connected to the second accommodating part for circulating the fluid. The plurality of light-emitting diode devices include a modifying compound on their surfaces, and the modifying compound includes a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

[0014] The weight-average molecular weight of the modifying compound may be 500 g / mol or less.

[0015] The hydrophilic functional group of the modifying compound may include phosphonic acid, and the hydrophobic functional group may include an alkyl group having 1 to 18 carbon atoms.

[0016] The organic solvent accommodated in the first accommodating part may be maintained at a temperature of 20 to 30 °C.

[0017] The plurality of ultrasonic generating parts can apply ultrasonic waves in a direction perpendicular to one surface of the substrate and drive simultaneously.

[0018] The system may further include a cooling part located in the channel part.

[0019] According to the second embodiment of the present invention, a method for separating a plurality of light-emitting diode devices from a substrate formed with a plurality of light-emitting diode devices is characterized in that it includes: step (a) of disposing an ultrasonic generating part at the lower part of an accommodating part and putting a substrate formed with a plurality of light-emitting diode devices and an organic solvent in the accommodating part; and step (b) of generating bubbles in the organic solvent by applying ultrasonic waves to the substrate, and allowing the generated bubbles to penetrate between the plurality of light-emitting diode devices to separate the plurality of light-emitting diode devices from the substrate. In step (a), the plurality of light-emitting diode devices formed on the substrate are disposed in the upward direction of the accommodating part.

[0020] According to the third embodiment of the present invention, a method for separating a plurality of light-emitting diode devices from a substrate on which the plurality of light-emitting diode devices are formed is characterized by including: step (a) of disposing an ultrasonic wave generating unit below a housing portion and placing a substrate on which the plurality of light-emitting diode devices are formed and an organic solvent in the housing portion; and step (b) of applying ultrasonic waves to the substrate to generate bubbles in the organic solvent, and causing the generated bubbles to penetrate between the plurality of light-emitting diode devices to separate the plurality of light-emitting diode devices from the substrate. In step (a), the plurality of light-emitting diode devices formed on the substrate are disposed in a direction toward the lower portion of the housing portion, and a surface layer of the plurality of light-emitting diode devices contains a modifying compound, and the modifying compound contains a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

[0021] According to the third embodiment, step (a) may include: step (a1) of disposing a housing portion having an ultrasonic wave generating unit below and placing an organic solvent in the housing portion; step (a2) of attaching a bracket to the other surface of a substrate on which the plurality of light-emitting diode devices are formed and placing the substrate in the housing portion by vertically moving the bracket; step (a3) of measuring the height of the organic solvent and matching the surface of the substrate with the surface of the organic solvent; and step (a4) of matching the interface between the substrate and the light-emitting diode devices with the node position of a standing wave by using the following formulas 1 and 2.

[0022] Formula 1: Wavelength (λ) of ultrasonic wave = ultrasonic wave velocity (v) of organic solvent / vibration frequency (f) of ultrasonic wave generating unit.

[0023] Formula 2: Standing wave node position (cm) = integer (n) from 1 to 10 × wavelength (λ) of ultrasonic wave / 2.

[0024] Moreover, when the vertical moving distance from the surface of the organic solvent to the substrate to which the bracket is attached is D and the height of the organic solvent is L, formula 3 can be satisfied: D = L - standing wave node position (cm).

[0025] According to the second embodiment or the third embodiment, the size of the bubbles may be smaller than the pitch between one light-emitting diode device and another light-emitting diode device formed on the substrate.

[0026] According to the second embodiment or the third embodiment, in step (b), the vibration frequency of the ultrasonic wave generating unit may be 120 to 200 kHz.

[0027] In this case, the weight average molecular weight of the modifying compound may be 500 g / mol or less. Moreover, the hydrophilic functional group of the modifying compound may contain phosphonic acid, and the hydrophobic functional group may contain an alkyl group having C1 to C18.

[0028] Effects of the Invention

[0029] The separation system of the light-emitting diode device of the present invention separately provides a housing part for housing the light-emitting diode device, thereby improving the separation efficiency of the light-emitting diode device.

[0030] Moreover, a hydrophilic functional group is bonded to the surface of the light-emitting diode device using a modifying compound, and a hydrophobic functional group is bonded to the other surface, thereby improving the phenomenon of agglomeration of the light-emitting diode devices occurring in the organic solvent during separation. Further, the organic solvent inside the housing part is maintained at a specified temperature by circulating through the fluid passage part, thereby minimizing the agglomeration phenomenon of the light-emitting diode devices.

[0031] The separation method of the light-emitting diode device of the present invention causes separation of the light-emitting diode device in the organic solvent using high-frequency ultrasonic waves, thereby having no external loss and also improving the uniformity of the length of the light-emitting diode device.

[0032] The specific effects of the present invention will be described together with the above effects in the description of the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Side view of the separation system of the light-emitting diode device according to the first embodiment of the present invention.

[0034] Figure 2 Top view of the separation system of the light-emitting diode device according to the first embodiment of the present invention.

[0035] Figure 3 Images of agglomerated light-emitting diode devices (part (a)) and images of light-emitting diode devices ensuring dispersibility (part (b)).

[0036] Figure 4 Schematic diagram showing the separation method of the light-emitting diode device according to the second embodiment of the present invention.

[0037] Figure 5 Schematic diagram showing the separation method of the light-emitting diode device according to the third embodiment of the present invention.

[0038] Figure 6 Graph showing the separation yield of the light-emitting diode device based on frequency in the second and third embodiments of the present invention.

[0039] Description of reference numerals:

[0040] The separation system of the light-emitting diode device of the present invention separately provides a housing part for housing the light-emitting diode device, thereby improving the separation efficiency of the light-emitting diode device.

[0041] 20: Second housing part;

[0042] 30, 33, 35: Ultrasonic wave generating part;

[0043] 40: Channel part;

[0044] 50: Cooling part;

[0045] 100, 200: Accommodating part;

[0046] 220, 320: Substrate;

[0047] 230, 330: Microbubble;

[0048] 400: Bracket;

[0049] 500: Z-axis adjustment stage. Detailed implementation manners

[0050] The foregoing objects, features and advantages will be described in detail with reference to the accompanying drawings in the following content. Those of ordinary skill in the technical field to which the present invention pertains can easily implement the technical idea of the present invention based on this. During the description of the present invention, when it is determined that the specific description of the well-known technology related to the present invention may unnecessarily confuse the gist of the present invention, its detailed description will be omitted. Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to represent the same or similar structural elements.

[0051] Hereinafter, when referring to the "upper part (or lower part)" of a structural element or when any structure is provided "above (or below)" a structural element, it not only means the case where any structure is provided in contact with the upper surface (or lower surface) of the said structural element, but also means the case where other structures are interposed between the said structural element and any structure provided above (or below) the said structural element.

[0052] Moreover, when referring to a certain structural element being "connected", "combined" or "coupled" with other structural elements, it not only means that the said structural elements are directly connected or coupled to each other, but it should also be understood that other structural elements may be "interposed" between the respective structural elements or the respective structural elements may be "connected", "combined" or "coupled" through other structural elements.

[0053] Hereinafter, a separation system for light-emitting diode devices and a method for separating light-emitting diode devices according to several embodiments of the present invention will be described.

[0054] According to the first embodiment of the present invention, the present invention relates to a separation system for light-emitting diode devices that effectively separates a plurality of light-emitting diode devices from a substrate in a manner without agglomeration of light-emitting diode devices in an organic solvent by applying ultrasonic waves to a hydrophobic-modified light-emitting diode device.

[0055] The separation system of the light-emitting diode device according to the first embodiment of the present invention is characterized in that it includes: a first accommodating portion 10 for accommodating a substrate formed with a plurality of light-emitting diode devices and an organic solvent; a second accommodating portion 20 disposed outside the first accommodating portion for accommodating the first accommodating portion and a fluid; a plurality of ultrasonic generating portions 30 disposed below the second accommodating portion for applying ultrasonic waves to the substrate; and a channel portion 40 connected to the second accommodating portion to circulate the fluid. In this case, preferably, a plurality of light-emitting diode devices include a modifying compound on their surfaces, and the modifying compound includes a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group. The fact that a plurality of light-emitting diode devices include a modifying compound may mean that the modifying compound is dispersed in the surface layer of the device, or the modifying compound is bonded or dispersed in the insulating layer.

[0056] As Figure 1 and Figure 2 shown, the separation efficiency of the light-emitting diode device can be improved by at least two ultrasonic generating portions located below the second accommodating portion, and the temperature of the organic solvent in the second accommodating portion can be maintained at room temperature by using fluid circulation. This has the effect of preventing the aggregation phenomenon of the light-emitting diode devices caused by the heat generated when applying ultrasonic waves.

[0057] In particular, if the light-emitting diode devices are modified with a modifying compound having a hydrophilic functional group and a hydrophobic functional group before separating a plurality of light-emitting diode devices from the substrate, the hydrophilic functional group is bonded to the surface of the insulating layer of the light-emitting diode device, and the hydrophobic functional group is located on the opposite side of the hydrophilic functional group, so that the insulating layer located on the outermost layer of the light-emitting diode device can be treated with the hydrophobic functional group. Thus, the surface of the light-emitting diode device is subjected to hydrophobic treatment, thereby further preventing the aggregation phenomenon of the light-emitting diode devices in the organic solvent.

[0058] The first accommodating portion 10 is used to accommodate the substrate formed with a plurality of light-emitting diode devices and the organic solvent, and is a space for separating the light-emitting diode devices. The organic solvent contained in the first accommodating portion does not circulate to the outside. Therefore, the separation and acquisition of the light-emitting diode devices can be completely realized inside the first accommodating portion. That is, a separate first accommodating portion is provided inside the accommodating portion, thereby having the effect of further improving the separation efficiency of the light-emitting diode devices.

[0059] The first accommodating portion may be formed of a strong material so as not to be deformed externally by ultrasonic waves. For example, the first accommodating portion may be formed of glass or metal material, but is not limited thereto.

[0060] The length of the bottom surface of the first accommodating portion can be about 1% to 10% relative to the length of the substrate. When the length of the bottom surface of the first accommodating portion is about 1% to 10% relative to the length of the substrate, the movement of the substrate can be minimized. During the separation by ultrasonic waves, since the substrate does not shake significantly, the substrate can be stably fixed within the first accommodating portion, and the light-emitting diode devices can be stably separated from the substrate. On the contrary, if the bottom surface length of the first accommodating portion is greater than 10% relative to the length of the substrate, the empty space inside the first accommodating portion is too large, resulting in significant shaking of the substrate when ultrasonic waves are applied. As a result, agglomeration of the separated light-emitting diode devices occurs due to the friction between the substrate and the bottom surface of the first accommodating portion.

[0061] The organic solvent can include isopropyl alcohol (IPA), acetone, ethanol, methanol, etc.

[0062] The substrate on which a plurality of light-emitting diode devices are formed grows the light-emitting diode devices by epitaxial growth method, and has a structure in which the plurality of light-emitting diode devices are arranged at intervals.

[0063] The substrate can include well-known transparent substrates such as sapphire substrates and glass substrates, but is not limited thereto. The length of the light-emitting diode device can be 3 to 10 μm, and the diameter can be 0.1 to 10 μm. Preferably, the length can be 4 to 6 μm, and the diameter can be 0.5 to 2 μm, but is not limited thereto. Also, the light-emitting diode device can be cylindrical or rod-shaped.

[0064] The light-emitting diode device can include an insulating layer on the outermost layer to wrap the plurality of semiconductor layers and electrode layers. The insulating layer can include silicon oxide (SiO x , 0 < x < 2), silicon nitride (SiN x , 0 < x < 2), silicon oxynitride (SiO x N y , 0 < x, y < 2), aluminum nitride (AlN), etc., but is not limited thereto.

[0065] In order to effectively separate and disperse the plurality of light-emitting diode devices formed on the substrate in the organic solvent, a process of improving the hydrophobicity of the light-emitting diode devices through pretreatment is required.

[0066] In order to minimize the agglomeration phenomenon of the light-emitting diode devices in the organic solvent, the key lies in imparting hydrophobicity to the insulating layer formed on the light-emitting diode devices.

[0067] From such a perspective, the modification reaction of the light-emitting diode devices can be carried out by dipping the substrate on which a plurality of light-emitting diode devices are formed in the modifying compound.

[0068] Preferably, a plurality of light-emitting diode devices contain a compound for modification that constitutes a surface treatment layer. Preferably, the compound for modification contains a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group. When the solubility of any part in water is greater than that of other parts, that part is called hydrophilic. When the solubility of any part in water is lower than that of other parts, that part is called hydrophobic.

[0069] By pre-hydrophobically treating the surfaces of a plurality of light-emitting diode devices formed on a substrate with a compound for modification, the light-emitting diode devices can be effectively separated from the substrate in an organic solvent. Ultrasonic waves can be applied to keep the light-emitting diode devices dispersed in the organic solvent for a specified time.

[0070] The compound for modification can contain hydrophilic functional groups such as phosphonic acid and can contain hydrophobic functional groups such as C1-C18 alkyl groups. Among them, for example, the hydrophobic functional group can contain a methyl group.

[0071] When the compound for modification contains phosphonic acid and a C1-C18 alkyl group, the phosphonic acid can bind to the insulating layer of the light-emitting diode device to sufficiently modify the light-emitting diode device to be hydrophobic. Thereby, the aggregation between the light-emitting diode device particles can be controlled during the separation process of the light-emitting diode devices, thus having the effect of further improving the separation yield of the light-emitting diode devices.

[0072] The weight-average molecular weight of the compound for modification can be 500 g / mol or less. Preferably, it can be 100-400 g / mol. More preferably, it can be 200-350 g / mol.

[0073] When the weight-average molecular weight of the compound for modification satisfies 500 g / mol or less, it has the effect of ensuring dispersibility by inducing independent alignment of the light-emitting diode devices. The above-mentioned compound for modification can contain the compounds shown in Table 1 below.

[0074] Table 1

[0075]

[0076] The organic solvent contained in the first accommodating portion can maintain a temperature of 20-30°C. Preferably, it can maintain a temperature of 23-28°C. More preferably, it can maintain a temperature of 24-26°C.

[0077] The fact that the organic solvent maintains a temperature of 20-30°C is achieved by the cooling portion 50 located in the channel portion. As the fluid moving along the channel portion is cooled by the cooling portion, the temperature of the organic solvent in the first accommodating portion is reduced.

[0078] Conventionally, light-emitting diode devices have been separated from a substrate in a volatile solvent such as an alcohol solvent. However, when ultrasonic waves are applied, the temperature inside the housing portion increases due to the generated heat, resulting in agglomeration of the light-emitting diode devices caused by the evaporation of the solvent.

[0079] To solve the above-mentioned conventional problems, the separation system of the present invention is provided with a channel portion and a cooling portion, and the composition of the compound for modification is a low-molecular-weight phosphonic acid, thereby having the effect of significantly improving the agglomeration phenomenon of the light-emitting diode devices.

[0080] Therefore, preferably, a cooling portion is provided at any position of the channel portion to lower the temperature of the organic solvent.

[0081] The second housing portion 20 serves to store and protect the first housing portion. A fluid can be stored in the second housing portion, and the heat generated by the ultrasonic waves is circulated through the fluid. The second housing portion can be formed of a metal material, but is not limited thereto.

[0082] In order to apply uniform ultrasonic waves to the entire area of the substrate, a plurality of ultrasonic wave generating portions can apply ultrasonic waves in a direction perpendicular to one side of the substrate, and a plurality of ultrasonic wave generating portions can be driven simultaneously.

[0083] The ultrasonic wave generating portion 30 can have a probe type shape. The probe type ultrasonic wave generating portion does not apply ultrasonic waves while moving in a stamping manner, but stably applies ultrasonic waves at a fixed position, and only applies ultrasonic waves to the relevant position where the ultrasonic wave generating portion is provided, so that the light-emitting diode devices at the relevant position can be stably and effectively separated.

[0084] For example, when two ultrasonic wave generating portions are respectively provided at positions A and B, ultrasonic waves can be applied in the upper direction of position A and the upper direction of position B.

[0085] The ultrasonic wave generating portion can apply a voltage for generating ultrasonic waves by being connected to an external device, and can be an ultrasonic transducer that converts electrical energy into mechanical vibration.

[0086] In particular, in the present invention, at least two ultrasonic wave generating portions are provided in direct contact with the lower portion of the second housing portion. Therefore, the distance between the substrate and the ultrasonic wave generating portion can be reduced, and the ultrasonic wave generation effect is high, so that the light-emitting diode devices can be smoothly separated. Moreover, since two or more ultrasonic wave generating portions are driven simultaneously, the separation efficiency of the light-emitting diode devices can be further improved by applying ultrasonic waves of uniform magnitude in a specified direction.

[0087] The channel portion 40 is a channel for the fluid to circulate in one direction, connected to the second accommodating portion, connecting one side and the other side of the second accommodating portion. Moreover, the channel portion can be located between multiple ultrasonic generating portions while being located below the second accommodating portion.

[0088] The fluid can be distilled water or an antifreeze formed by mixing water and ethylene glycol. The fluid can move along the channel portion in the form of a pipe after being discharged from the cooling portion, flow into the cooling portion through the lower part of the second accommodating portion. The temperature of the fluid discharged from the cooling portion is relatively low, so it has the advantage of further reducing the temperature of the organic solvent in the first accommodating portion.

[0089] The cooling portion 50 can be arranged adjacent to the second accommodating portion or on the opposite side of the second accommodating portion. Preferably, by being arranged on the opposite side of the second accommodating portion, the amount and speed of the fluid cooled by the cooling portion and the fluid flowing into the cooling portion can be evenly adjusted.

[0090] A structure capable of reducing the temperature of the fluid can be used without limitation.

[0091] In this way, the separation system of the light-emitting diode device according to the first embodiment of the present invention uses a light-emitting diode device surface-treated with a low-molecular-weight modifying compound, a first accommodating portion as a special container, a second accommodating portion for accommodating a fluid, multiple ultrasonic generating portions, and a channel portion for circulating the fluid, and has the effect of effectively separating multiple light-emitting diode devices from the substrate in an organic solvent without the agglomeration phenomenon of the light-emitting diode devices occurring.

[0092] The separation method of the light-emitting diode device using the separation system of the light-emitting diode device according to the first embodiment is as follows.

[0093] After preparing the first accommodating portion and the second accommodating portion, the first accommodating portion is arranged inside the second accommodating portion. The first accommodating portion can be used to accommodate a substrate formed with multiple light-emitting diode devices and an organic solvent, and the second accommodating portion can accommodate a fluid.

[0094] Ultrasonic waves are applied to the substrate by using multiple ultrasonic generating portions, and ultrasonic waves are applied in a direction perpendicular to one surface of the substrate, and the separation and dispersion operations of the light-emitting diode devices can be performed by simultaneously driving multiple ultrasonic generating portions.

[0095] In this case, by using the channel portion connected to the second accommodating portion and the cooling portion located in the channel portion to circulate the fluid inside the channel portion, the temperature of the organic solvent accommodated in the first accommodating portion can be maintained at 20 - 30 °C.

[0096] When separating the light-emitting diode device completely from the substrate in an organic solvent, the power supply of the cooling unit and the ultrasonic generating unit can be interrupted, and the light-emitting diode device can be effectively obtained in a short time by filtering the substrate and the light-emitting diode device contained in the organic solvent. Moreover, since separation occurs in the solution by using ultrasonic waves, there is no loss to the outside, thus having the advantage of improving the uniformity of the length of the light-emitting diode device.

[0097] Figure 3 Images of agglomerated light-emitting diode devices ((a) part) and light-emitting diode devices ensuring dispersibility ((b) part).

[0098] In Figure 3 , in the (a) part, after preparing the first accommodating part for accommodating a plurality of light-emitting diode devices that have not been subjected to hydrophobic treatment, a plurality of probe-type ultrasounds are applied in the vertical direction with respect to one surface of the substrate, and the temperature of the organic solvent is controlled to be 30 °C by controlling the fluid circulation.

[0099] Figure 3 In the (b) part of , using the separation system of the first embodiment, after preparing the first accommodating part for accommodating a plurality of light-emitting diode devices modified with a modifying compound (ODPA: 500 g / mol, mixed with IPA), a plurality of probe-type ultrasounds are applied in the vertical direction with respect to one surface of the substrate, and the temperature of the organic solvent is maintained at 20 - 23 °C by fluid circulation.

[0100] Figure 3 The measurement method is to set the objective lens of the optical microscope to 50x and the eyepiece to 0.5x. Considering the sample position deviation, after measuring the separation yield at positions where there are 10 - 20 light-emitting diode devices, the agglomerated image ((a) part) is compared with the dispersed image ((b) part) based on the average value.

[0101] In Figure 3 In the (a) part of , since the surface of the light-emitting diode device has not been subjected to hydrophobic treatment, the light-emitting diode devices agglomerate immediately after being separated from the light-emitting diode substrate and agglomerate rapidly due to the temperature rise of the organic solvent.

[0102] On the contrary, in Figure 3 In the (b) part of , light-emitting diode devices pretreated with hydrophobicity using ODPA are used, and the temperature of the organic solvent is maintained below 25 °C by fluid circulation, thereby improving the dispersibility among the light-emitting diode devices in the organic solvent, and it is confirmed that they can be stored and used for a long time.

[0103] According to a second embodiment of the present invention, the present invention relates to a method for separating light-emitting diode devices as follows: A plurality of light-emitting diode devices formed on a substrate are arranged in an upward direction, so that the plurality of light-emitting diode devices can be effectively separated from the substrate by using microbubbles generated when high-frequency ultrasonic waves are applied.

[0104] Furthermore, according to a third embodiment, the present invention relates to a method for separating light-emitting diode devices as follows: A plurality of light-emitting diode devices formed on a substrate are arranged in a downward direction, so that the plurality of light-emitting diode devices can be effectively separated from the substrate by using high-frequency ultrasonic waves and wave energy (shock waves).

[0105] According to the second and third embodiments, a plurality of light-emitting diode devices can be surface-treated with a modifying compound including a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group, and the light-emitting diode devices can be separated by microbubbles in an organic solvent. Therefore, there is no loss to the outside, and thus the effect of improving the uniformity of the length of the light-emitting diode devices is achieved.

[0106] According to a second embodiment of the present invention, a method for separating a plurality of light-emitting diode devices from a substrate on which the plurality of light-emitting diode devices are formed is characterized by including: a step of disposing an ultrasonic wave generating unit at a lower part of a receiving portion and placing the substrate on which the plurality of light-emitting diode devices are formed and an organic solvent in the receiving portion; and a step of separating the plurality of light-emitting diode devices from the substrate by generating bubbles in the organic solvent by applying ultrasonic waves to the substrate and causing the generated bubbles to penetrate between the plurality of light-emitting diode devices.

[0107] In this case, in the placing step, preferably, the plurality of light-emitting diode devices formed on the substrate are arranged in an upward direction of the receiving portion.

[0108] Figure 4 A schematic diagram showing the method for separating light-emitting diode devices according to a second embodiment of the present invention.

[0109] As Figure 4 shown, a plurality of light-emitting diode devices can be separated from a substrate 220 by using a receiving portion 100 provided with an ultrasonic wave generating unit 33 at a lower part.

[0110] The receiving portion 100 is used to receive the substrate on which the plurality of light-emitting diode devices are formed and the organic solvent, and is a space for separating the light-emitting diode devices. The organic solvent contained in the first receiving portion does not circulate to the outside. Therefore, the separation and acquisition of the light-emitting diode devices can be completely realized inside the first receiving portion. The receiving portion can be formed of a strong material so as not to be externally deformed by ultrasonic waves. For example, the receiving portion can be formed of a glass or metal material, but is not limited thereto.

[0111] In order to apply uniform ultrasonic waves to the entire area of the substrate, the ultrasonic wave generating unit 33 can apply ultrasonic waves in a direction perpendicular to one side of the substrate, and multiple ultrasonic wave generating units can be driven simultaneously. The ultrasonic wave generating unit can include multiple probe-type shapes. Instead of applying ultrasonic waves while moving in a stamping manner, ultrasonic waves are stably applied at fixed positions, and ultrasonic waves are only applied to the relevant positions where the ultrasonic wave generating unit is provided, so that the light-emitting diode devices at the relevant positions can be stably and effectively separated. In particular, multiple ultrasonic wave generating units can be arranged in direct contact with the lower surface of the accommodating part. The ultrasonic wave generating unit can apply a voltage for generating ultrasonic waves by connecting to an external device, and can be an ultrasonic transducer that converts electrical energy into mechanical vibration.

[0112] The accommodating part can simultaneously place the substrate formed with multiple light-emitting diode devices and the organic solvent, or place the substrate and the organic solvent in sequence, or place the organic solvent and the substrate in sequence. However, in order to minimize damage to the light-emitting diode devices, preferably, the substrate is placed after the organic solvent is placed. Also, when placing the organic solvent, the amount of the organic solvent can be adjusted so that the substrate is fully immersed in the organic solvent.

[0113] In this case, the direction of the substrate formed with multiple light-emitting diode devices can be set. After the substrate is arranged adjacent to the ultrasonic wave generating unit in a manner parallel to the lower surface of the accommodating part and perpendicular to the light-emitting diode devices, the dispersion step can be performed. If the substrate is arranged in this way, during the application of ultrasonic waves, microbubbles generated can infiltrate between the light-emitting diode devices in a uniform amount, stably separating the light-emitting diode devices and storing them in the organic solvent.

[0114] The substrate formed with multiple light-emitting diode devices and the organic solvent are the same as those described in the first embodiment, and the description thereof is omitted here.

[0115] When ultrasonic waves are applied to the substrate, microbubbles like cavities are generated in the organic solvent as pressure is generated. During the generation of microbubbles, cavitation energy is transmitted, so that the separation of the light-emitting diode devices can be achieved by applying a force between the substrate and the light-emitting diode devices.

[0116] That is, the bubbles generated by ultrasonic waves in the organic solvent infiltrate between multiple light-emitting diode devices, so that multiple light-emitting diode devices can be separated from the substrate.

[0117] The commonly used ultrasonic frequency is low frequency, and the size of the bubbles is very large. If the size of the bubbles is too large, the bubbles cannot infiltrate between multiple light-emitting diode devices, so there is a problem that the transfer efficiency of the bubbles drops sharply.

[0118] To solve such a problem, as Figure 4As shown, in the present invention, the high frequency of ultrasonic waves is utilized to control the size of the bubbles, thereby significantly improving the separation efficiency of light-emitting diode devices.

[0119] In order to apply high-frequency ultrasonic waves, preferably, the vibration frequency of the ultrasonic wave generating unit is 120 - 200 kHz, more preferably, 120 - 180 kHz, and even more preferably, 125 - 160 kHz.

[0120] When the vibration frequency satisfies 120 - 200 kHz, it is beneficial to generate microbubbles in the organic solvent, and it has the effect of effectively separating multiple light-emitting diode devices formed on the substrate within a short time. In particular, within the range of the vibration frequency of 120 - 200 kHz, a separation yield of more than 60% of the light-emitting diode devices can be shown, and preferably, a separation yield of more than 70% of the light-emitting diode devices can be shown. The separation yield can be calculated by the following method: [1 - (the area occupied by the light-emitting diode devices on the substrate after separation / the area occupied by the light-emitting diode devices on the substrate before separation)] × 100%.

[0121] In order to improve the separation efficiency of the light-emitting diode devices, the size of the bubbles in the organic solvent can be smaller than the distance between one light-emitting diode device and another light-emitting diode device formed on the substrate. Moreover, the bubbles generated by ultrasonic waves tend to become smaller as the frequency increases. Therefore, the key lies in controlling the size of the bubbles by considering the frequency and the distance between the light-emitting diode devices. For example, the length of the light-emitting diode device can be 3 - 10 μm, the diameter can be 0.1 - 10 μm, and the size of the bubbles can be 1 - 10 μm, preferably, 2 - 5 μm.

[0122] In this way, the method for separating light-emitting diode devices according to the second embodiment of the present invention utilizes high-frequency ultrasonic waves in a state where the direction of the light-emitting diode devices formed on the substrate faces upward, and has the effect of separating multiple light-emitting diode devices in a uniform manner with the length and cutting surface of the light-emitting diode devices by microbubbles.

[0123] According to the third embodiment of the present invention, a method for separating multiple light-emitting diode devices from a substrate on which multiple light-emitting diode devices are formed is characterized by including: a step of disposing an ultrasonic wave generating unit below a receiving portion and placing the substrate on which multiple light-emitting diode devices are formed and an organic solvent in the receiving portion; and a step of generating bubbles in the organic solvent by applying ultrasonic waves to the substrate, and separating multiple light-emitting diode devices from the substrate by allowing the generated bubbles to penetrate between the multiple light-emitting diode devices.

[0124] In this case, in the step of placing the substrate on which a plurality of light-emitting diode devices are formed and the organic solvent, preferably, the plurality of light-emitting diode devices formed on the substrate are arranged in a direction toward the lower part of the accommodating portion. The reason for arranging the substrate in this way is to make the interface between the substrate and the light-emitting diode devices located at the position where the amplitude of the standing wave is the largest after simultaneously applying high-frequency ultrasonic waves and fluctuating energy, thereby maximizing the separation efficiency of the light-emitting diode devices.

[0125] Figure 5 A schematic diagram showing a method for separating a light-emitting diode device according to a third embodiment of the present invention.

[0126] As Figure 5 shown, by vertically moving the substrate 230 in the organic solvent, the interface between the substrate and the light-emitting diode devices is matched with the node position of the standing wave, thereby having the effect of maximizing the separation efficiency of the light-emitting diode devices. Figure 5 The size of the bubbles shown is only one embodiment, and the present invention is not limited thereto.

[0127] The accommodating portion 200 provided with the ultrasonic wave generating portion 35 at the lower part is the same as the accommodating portion 100 provided with the ultrasonic wave generating portion 33 in the second embodiment, and the description thereof is omitted herein.

[0128] The method for separating the light-emitting diode device is a device in which a bracket 400 is provided (connected) on a z-axis adjustment stage 500, and the substrate 230 can be moved vertically in the organic solvent.

[0129] Specifically, the step of placing the substrate and the organic solvent may include: setting an accommodating portion provided with an ultrasonic wave generating portion at the lower part, and the step of placing the organic solvent into the accommodating portion; after attaching the bracket to the other side of the substrate on which a plurality of light-emitting diode devices are formed, the step of placing the substrate into the accommodating portion by vertically moving the bracket; the step of measuring the height of the organic solvent and matching the surface of the substrate with the surface of the organic solvent; and the step of matching the interface between the substrate and the light-emitting diode devices with the node position of the standing wave by using the following formulas 1 and 2.

[0130] Formula 1: Wavelength (λ) of ultrasonic wave = ultrasonic wave velocity (v) of organic solvent / vibration frequency (f) of ultrasonic wave generating portion.

[0131] Formula 2: Node position (cm) of standing wave = integer (n) from 1 to 10 × wavelength (λ) of ultrasonic wave / 2

[0132] After calculating the wavelength (λ) of the ultrasonic wave using Equation 1, the node position (cm) of the standing wave can be calculated using Equation 2. The interface between the substrate and the light-emitting diode device can be matched with the node position of the standing wave by vertically moving the standing wave in the z-axis direction (perpendicular to the bottom surface of the housing) within the possible water depths. Among them, the standing wave is confined within a space where the wave motion is restricted, showing a form of in-situ vibration, and is a wave with a fixed node position.

[0133] Matching the shown interface with the node position of the standing wave can be carried out by vertically moving the substrate with the attached bracket from the surface of the organic solvent.

[0134] Therefore, when the distance that the substrate with the attached bracket moves vertically from the surface of the organic solvent is D and the height of the organic solvent is L, Equation 3 can be satisfied: D = L - the node position (cm) of the standing wave.

[0135] For example, prepare a housing with an ultrasonic generating part provided at the lower part, and put an organic solvent into the housing. Then, after attaching a bracket to the other side of the substrate on which a plurality of light-emitting diode devices are formed, the substrate is put into the housing by vertically moving the bracket.

[0136] Next, match the surface of the substrate with the surface of the organic solvent.

[0137] When using Equation 1 (wavelength (λ) of the ultrasonic wave = ultrasonic velocity (v) of the organic solvent / vibration frequency (f) of the ultrasonic generating part), when the vibration frequency (f) of the ultrasonic generating part is 132 kHz and the ultrasonic velocity in the organic solvent is 1125 m / s, the wavelength (λ) of the ultrasonic wave = (1.13×10 3 m / s) / (1.32×10 5 / s) = 0.86 cm.

[0138] When setting n = 3 in Equation 2 (node position (cm) of the standing wave = integer (n) from 1 to 10 × wavelength (λ) of the ultrasonic wave / 2), the node position (cm) of the standing wave = 3λ / 2 = 1.29 cm.

[0139] That is to say, when the height L of the organic solvent = 5 and λ = 4.3 cm, if using Equation 3 (distance D that the substrate with the attached bracket moves vertically from the surface of the organic solvent = height L of the organic solvent - node position (cm) of the standing wave), then D = 4.3 cm - 1.29 cm = 3.01 cm.

[0140] In order to maximize the generation of high-frequency bubbles and the impact of wave energy (shock waves), the substrate with the stent attached can be moved 3.01 cm in the downward direction (z-axis direction) from the surface of the organic solvent so that the interface between the substrate and the light-emitting diode device matches the position of 1.29 cm, which is the node position of the standing wave.

[0141] Then, ultrasonic waves are applied to the substrate to generate bubbles in the organic solvent, and the generated bubbles penetrate between multiple light-emitting diode devices, so that multiple light-emitting diode devices can be separated from the substrate.

[0142] If pressure is generated in the organic solvent by high-frequency ultrasonic waves, microbubbles are generated, and the size of the bubbles can be smaller than the spacing between one light-emitting diode device and another light-emitting diode device formed on the substrate. The size of the bubbles is the same as that described in the second embodiment, and the description thereof is omitted here.

[0143] Moreover, preferably, the vibration frequency of the ultrasonic wave generating unit is 120 to 200 kHz, and within this range, there is an effect of maximizing both the wave energy and the separation efficiency of the light-emitting diode device.

[0144] Matters related to the vibration frequency are the same as those described in the second embodiment, and the description thereof is omitted here.

[0145] In this way, the method for separating the light-emitting diode device according to the third embodiment of the present invention utilizes high-frequency ultrasonic waves and wave energy in a state where the direction of the light-emitting diode device formed on the substrate faces downward, and has the effect of further improving the separation yield through physical impact force.

[0146] Figure 6 It is a graph showing the separation yield of the light-emitting diode device based on frequency in the second and third embodiments of the present invention.

[0147] In the second embodiment (Embodiment 2) and the third embodiment (Embodiment 3), during the experiment on the separation yield of the light-emitting diode device based on frequency, it was confirmed that the size of the microbubbles generated by the ultrasonic waves decreases in inverse proportion to the frequency. When the ultrasonic wave frequency is greater than or equal to 40 kHz and less than 80 kHz, the size of the microbubbles is shown to be greater than 10 μm and less than or equal to 50 μm, and when the ultrasonic wave frequency is 120 to 200 kHz, the size of the microbubbles is shown to be 1 to 10 μm.

[0148] Refer to Figure 6 the graphs of Embodiment 2 and Embodiment 3 in, when the ultrasonic wave frequency approaches 40 kHz, the separation efficiency is below 20%, because the size of the microbubbles is too large to penetrate between the light-emitting diode devices. It is considered that this is because the energy for cutting the interface between the light-emitting diode devices is too small, resulting in low separation efficiency.

[0149] When the ultrasonic frequency is greater than or equal to 80 kHz and less than or equal to 170 kHz, the size of the microbubbles is similar to the spacing between the light-emitting diode devices. Therefore, energy is effectively transferred. As a result, a separation efficiency of more than 70% is shown.

[0150] When the ultrasonic frequency is greater than 170 kHz, although it penetrates well between the light-emitting diode devices due to the reduced size of the microbubbles, the size of the microbubbles is too small, and the generated energy is also small, resulting in the disadvantage that it is difficult to effectively separate the light-emitting diode devices.

[0151] In particular, observing the graph of Example 3 using the node position of the microbubbles and the standing wave, it can be seen that energy is well transferred to the interface between the substrate and the light-emitting diode devices, thereby further improving the separation yield of the light-emitting diode devices. This indicates that the separation efficiency can be improved by using physical impact force.

[0152] Therefore, it can be confirmed that when the ultrasonic frequency of the present invention is 80 - 180 kHz, the separation efficiency of the light-emitting diode devices is excellent, and when the ultrasonic frequency is 120 - 170 kHz, the separation efficiency of the light-emitting diode devices is even more excellent.

[0153] As described above, the present invention has been illustrated with reference to the example figures. However, the present invention is not limited to the embodiments and drawings disclosed in this specification. Obviously, various modifications can be made by those of ordinary skill in the technical field to which the present invention pertains within the scope of the technical idea of the present invention. At the same time, during the description of the embodiments of the present invention, even if the effects of the structure of the present invention are not explicitly described, the effects that can be predicted by the relevant structure should also be recognized.

Claims

1. A separation system for light-emitting diode devices, using hydrophobic modified light-emitting diode devices, characterized in that it includes: A first accommodating part for accommodating a substrate formed with a plurality of light-emitting diode devices and an organic solvent; A second accommodating part arranged outside the first accommodating part for accommodating the first accommodating part and a fluid; A plurality of ultrasonic generating parts arranged at the lower part of the second accommodating part for applying ultrasonic waves to the substrate; and A channel part connected to the second accommodating part for circulating the fluid, The plurality of light-emitting diode devices contain a modifying compound on their surfaces, The modifying compound includes a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

2. The separation system of the light-emitting diode device according to claim 1, characterized in that, The weight-average molecular weight of the modifying compound is 500 g / mol or less.

3. The separation system of the light-emitting diode device according to claim 1, characterized in that, The hydrophilic functional group of the modifying compound includes phosphonic acid, and the hydrophobic functional group includes an alkyl group of C1-C18.

4. The separation system of the light-emitting diode device according to claim 1, wherein, The organic solvent accommodated in the first accommodating part maintains a temperature of 20-30°C.

5. The separation system of the light-emitting diode device according to claim 1, wherein The plurality of ultrasonic generating parts apply ultrasonic waves in a direction perpendicular to one surface of the substrate and drive simultaneously.

6. The separation system of the light-emitting diode device according to claim 1, characterized in that, It further includes a cooling part located in the channel part.

7. A method for separating light-emitting diode devices, which is a method for separating a plurality of light-emitting diode devices from a substrate formed with a plurality of light-emitting diode devices, characterized in that it includes: Step (a), arranging an ultrasonic generating part at the lower part of the accommodating part, and placing a substrate formed with a plurality of light-emitting diode devices and an organic solvent in the accommodating part; and Step (b), generating bubbles in the organic solvent by applying ultrasonic waves to the substrate, and allowing the generated bubbles to penetrate between the plurality of light-emitting diode devices to separate the plurality of light-emitting diode devices from the substrate, In the step (a), the plurality of light-emitting diode devices formed on the substrate are arranged in the upward direction of the accommodating part, The plurality of light-emitting diode devices contain a modifying compound on their surfaces, The modifying compound includes a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

8. A method for separating light-emitting diode devices, which is a method for separating a plurality of light-emitting diode devices from a substrate formed with a plurality of light-emitting diode devices, characterized in that it includes: Step (a), arranging an ultrasonic generating part at the lower part of the accommodating part, and placing a substrate formed with a plurality of light-emitting diode devices and an organic solvent in the accommodating part; and Step (b), generating bubbles in the organic solvent by applying ultrasonic waves to the substrate, and allowing the generated bubbles to penetrate between the plurality of light-emitting diode devices to separate the plurality of light-emitting diode devices from the substrate, In the step (a), the plurality of light-emitting diode devices formed on the substrate are arranged in the downward direction of the accommodating part, The plurality of light-emitting diode devices contain a modifying compound on their surfaces, The modifying compound includes a hydrophilic functional group located on the surface of the light-emitting diode device and a hydrophobic functional group located on the opposite side of the hydrophilic functional group.

9. According to the method for separating light-emitting diode devices according to claim 8, characterized in that The said step (a) includes: Step (a1), providing a housing with an ultrasonic generating part at the lower part, and putting an organic solvent into the housing; Step (a2), after attaching a bracket to the opposite surface of a substrate formed with a plurality of light emitting diode devices, putting the substrate into the housing by vertically moving the bracket; Step (a3), measuring the height of the organic solvent and making the surface of the substrate match the surface of the organic solvent; and Step (a4), making the interface between the substrate and the light emitting diode device match the node position of the standing wave by using the following Formula 1 and Formula 2, Formula 1: Wavelength of ultrasonic wave (λ) = ultrasonic velocity (v) of the organic solvent / vibration frequency (f) of the ultrasonic generating part, Formula 2: Node position of standing wave (cm) = integer (n) from 1 to 10 × wavelength of ultrasonic wave (λ) / 2.

10. The separation method of the light-emitting diode device according to claim 9, characterized in that, When the vertical moving distance from the surface of the organic solvent to the substrate with the attached bracket is D and the height of the organic solvent is L, the following Formula 3 is satisfied, Formula 3: D = L - node position of standing wave (cm).

11. The separation method of the light-emitting diode device according to claim 7 or 8, characterized in that, The size of the said bubbles is smaller than the spacing between one light emitting diode device and another light emitting diode device formed on the substrate.

12. The separation method of the light-emitting diode device according to claim 7 or 8, characterized in that, In the said step (b), the vibration frequency of the ultrasonic generating part is 120 - 200 kHz.

13. The separation method of the light-emitting diode device according to claim 7 or 8, characterized in that, The weight average molecular weight of the said compound for modification is 500 g / mol or less.

14. The separation method of the light-emitting diode device according to claim 7 or 8, characterized in that, The hydrophilic functional group of the said compound for modification contains phosphonic acid, and the hydrophobic functional group contains an alkyl group of C1 - C18.

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