Micro LED transfer device, manufacturing method thereof, and micro LED transfer method

Abstract

The present invention provides a micro LED transfer device comprising: a substrate; and a hollow structure disposed on the substrate to protrude therefrom, wherein the hollow structure has an empty interior and includes a hollow support part protruding from the substrate and fixed to the substrate, and an adsorption part disposed below the hollow support part and exposed to the outside, and the adsorption part has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

Description

Micro LED transfer device, manufacturing method thereof, and micro LED transfer method

[0001] This invention claims the benefit of Korean Patent Application No. 10-2023-0131716 filed with the Korean Intellectual Property Office on October 04, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a micro LED transfer device, a method for manufacturing the same, and a micro LED transfer method.

[0003]

[0004] Micro LEDs are small LEDs that are typically manufactured in the 10 to 100 μm range and can be applied to various fields such as stretchable substrates and flexible substrates, wearable displays, skin-attached medical devices, semiconductor equipment, autonomous driving sensors, and light sources for big data services.

[0005] Typically, microLEDs are manufactured by epitaxially growing GaN or other materials on sapphire or silicon wafers.

[0006] However, since micro LEDs are small, less than several tens of micrometers in size, they are not suitable for use without removing sapphire or silicon wafers with a thickness of 100 micrometers or more.

[0007] Therefore, it is common to include a process of separating the micro LED from a sapphire or silicon wafer and transferring it to another target substrate.

[0008] That is, transfer is a series of actions to transfer one or more micro LEDs to a target substrate.

[0009] The existing method of transferring a single LED chip was to apply it in the packaging process using pick and place equipment, but as the size of the LED decreased to several micrometers, it was difficult to match the work speed with the existing pick and place and there was a problem of difficulty in precise transfer.

[0010] Meanwhile, another transfer method utilizes an electrostatic head. This method works by applying voltage to a head made of silicon material, which generates an electrical charge, thereby creating a bond between the microLED and the head.

[0011] This method has the advantage of being able to selectively transfer a desired area or a single LED chip, but when static electricity is induced, a charging phenomenon occurs due to the voltage applied to the head, which may cause damage to the micro LED.

[0012] Another method is to apply a transfer head made of an elastic polymer material to transfer micro LEDs on a wafer to a desired substrate.

[0013] Compared to the electrostatic head method, there is no problem with LED damage, but there is a disadvantage in that the adhesive strength of the target substrate must be greater than the adhesive strength of the elastic transfer head during the transfer process to stably transfer the micro LED, and an additional process for electrode formation is required.

[0014] That is, in the case of transfer of micro LEDs, there is a need for research on transfer technology that can freely control adsorption and desorption, and that can perform adsorption and desorption even in a humid environment or in water.

[0015]

[0016] The present invention relates to a micro LED transfer device, a method for manufacturing the same, and a micro LED transfer method.

[0017]

[0018] In order to solve the above-mentioned conventional problem, according to one embodiment of the present invention, a micro LED transfer device is provided, which includes a substrate and a hollow structure protrudingly arranged on the substrate, wherein the hollow structure is a hollow support portion protruding from the substrate and fixed to the substrate, and an adsorption portion disposed below the hollow support portion and exposed to the outside, wherein the adsorption portion has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

[0019] The Young's modulus of the above adsorption portion may be smaller than the Young's modulus of the above hollow support portion.

[0020] The hollow structure may include at least one shape memory polymer selected from the group consisting of polynorbornene, polyurethane, trans-polyisoprene, styrene-butadiene copolymer, poly(ε-caprolactone), polycyclooctene, polyethylene glycol, liquid crystal polyester, liquid crystal elastomer, and polyethylene.

[0021] The above hollow support is characterized in that it is filled with a solid material.

[0022] The height of the above hollow support may be 40% or more and 80% or less of the total height of the above hollow structure.

[0023] The above-mentioned device may have a through hole connected to the hollow support.

[0024] A pressure control unit that is connected to the through hole and can control the pressure inside the structure may be further disposed on the other side of the substrate facing the one side on which the hollow structure is disposed.

[0025] The above pressure control unit may further include a valve that operates by an external signal.

[0026] Another embodiment of the present invention provides a method for manufacturing a micro LED transfer device, comprising the steps of: manufacturing a mold having a groove formed therein for forming a hollow structure; filling a portion of a first material in the groove of the mold; additionally filling a second material in the groove of the mold; attaching and curing a substrate to cover the groove of the mold; and separating the cured structure from the mold in the groove of the mold, wherein the cured first material forms an adsorption portion, the cured second material forms a hollow support portion, and the hollow structure has an internally hollow structure including a hollow support portion protruding from the substrate and fixed to the substrate and an adsorption portion disposed below the hollow support portion and exposed to the outside, wherein the adsorption portion has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

[0027] Another embodiment of the present invention provides a micro-LED transfer method using a micro-LED transfer device, including the steps of forming a micro-LED on a wafer, attaching the micro-LED transfer device to the micro-LED, adsorbing the micro-LED and detaching it from the wafer, transferring the micro-LED adsorbed on the micro-LED transfer device to another substrate, and detaching the micro-LED from the micro-LED transfer device, wherein the step of attaching the micro-LED transfer device to the micro-LED is performed by radially expanding an adsorbing portion of the micro-LED transfer device.

[0028] The step of transferring the micro LED attached to the micro LED transfer device to another substrate can be performed by positioning the micro LED on a solder ball arranged on the other substrate and applying heat.

[0029] The step of detaching the micro LED from the micro LED transfer device can be performed by causing the adsorption portion of the micro LED transfer device to return to its original shape due to the applied heat.

[0030]

[0031] According to one embodiment of the present invention, after attaching a micro LED transfer device to a micro LED, in the process of lifting a hollow structure including an adsorption portion having a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid, an adsorption force can be generated by a pressure difference between the inside and the outside of the hollow structure, so that in the case of transferring a micro LED, adsorption and desorption can be freely controlled.

[0032] In particular, a micro LED transfer device capable of adsorption and desorption even in a humid environment or in water can be provided.

[0033] In addition, the present invention controls absorption and desorption according to the height of the hollow support portion among the hollow structures, filling a solid material inside the support portion of the hollow structure, or the shape of the inlet of the absorption portion, thereby enabling the transfer of micro LEDs by the micro LED transfer device to proceed without error.

[0034] Specifically, according to one embodiment of the present invention, when the height of the support portion in the hollow structure is manufactured to be large, there is an advantage in that it can be easily detached when a shear force is applied.

[0035] In addition, according to one embodiment of the present invention, the planar shape of the adsorption portion in the structure can be transformed into various shapes such as a circle, a triangle, an ellipse, an asymmetrical shape, or a symmetrical shape. In particular, when the planar shape of the adsorption portion in the structure is a triangle, the detachment occurs easily from the pointed side, whereas the detachment is difficult when detached from the opposite side, so there is an effect that the detachment can be controlled depending on the detachment direction.

[0036] In addition, in the above structure, if the plane shape of the adsorption portion is an ellipse with different widths of the long and short axes, detachment occurs easily in the short axis direction, whereas detachment is difficult when detached in the long axis direction, so there is an effect of being able to control detachment depending on the detachment direction.

[0037] In addition, in the present invention, by using a material of the adsorption portion that is sensitive to external stimuli such as heat, light, and pH, the Young's modulus of the adsorption portion can be changed by the external stimuli, so that the stress used for stretching becomes greater than the adsorption force, thereby allowing spontaneous desorption to occur.

[0038] In addition, in a micro LED transfer device according to an embodiment of the present invention, a through hole connected to the hollow support part may be arranged in the substrate, and a pressure control part that is connected to the through hole and can control the pressure inside the hollow structure is further arranged on the other side of the substrate facing the one side where the hollow structure is arranged, so that the micro LED can be quickly absorbed and desorbed by a change in the internal pressure using the means.

[0039] In addition, only the micro LED at the desired location can be absorbed and desorbed through a valve operated by an external signal placed in the pressure control unit.

[0040]

[0041] FIG. 1 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a first embodiment of the present invention.

[0042] FIG. 2 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a second embodiment of the present invention.

[0043] FIG. 3 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a third embodiment of the present invention.

[0044] FIG. 4 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a fourth embodiment of the present invention.

[0045] FIG. 5 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a fifth embodiment of the present invention.

[0046] FIG. 6 is a schematic diagram showing a micro LED transfer device having a structure according to a sixth embodiment of the present invention.

[0047] Fig. 7 is a schematic diagram showing a micro LED transfer device having a structure according to the seventh embodiment of the present invention.

[0048] FIG. 8 is a schematic diagram showing a micro LED transfer method using a micro LED transfer device having a structure according to the first embodiment of the present invention.

[0049] FIG. 9 is a schematic diagram showing a micro LED transfer method using a micro LED transfer device having a structure according to the seventh embodiment of the present invention.

[0050] ※ Explanation of symbols

[0051] 1: Micro LED transfer device

[0052] 10: Description 20, 20', 20'': Hollow structure

[0053] 20a, 20a', 20a'': Hollow support 20b, 20b', 20b'': Adsorption part

[0054] 30: Solid material 40: Pressure control unit

[0055] 40a: Chamber 40b: Pressure regulator

[0056] 100: Wafer 200: Micro LED

[0057] 300: Other boards 400: Solder balls

[0058]

[0059] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0060] In this specification, when it is said that a member is located “on” another member, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0061] In this specification, the terms “step of” and “step of” do not mean “step for”.

[0062] In this specification, “adsorption” as used in “adsorption part” means physical adsorption for fixing an object or moving an object using vacuum.

[0063]

[0064] The specific details for implementing the present invention will be described in detail with reference to the attached drawings below.

[0065] FIG. 1 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a first embodiment of the present invention.

[0066] According to a first embodiment of the present invention, a micro LED transfer device (1) is provided, which includes a substrate (10) and a hollow structure (20) protruding and arranged on the substrate (10), wherein the hollow structure (20) has an internally hollow structure including a hollow support (20a) protruding from the substrate (10) and fixed to the substrate, and an adsorption part (20b) arranged on the upper portion of the hollow support part (20a) and exposed to the outside, wherein the adsorption part (20b) has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

[0067] The above-mentioned substrate (10) is not particularly limited and may be, for example, a substrate or a film. Specifically, it may be a glass substrate or a polyethylene terephthalate (PET) film.

[0068] The above hollow support member (20a) has a hollow structure inside and can have any one of the shapes of a cylinder, an elliptical cylinder, and a square cylinder.

[0069] The above-mentioned adsorption part (20b) has a structure with an empty interior, and since the adsorption part (20b) has a shape of one of a truncated cone, an elliptical truncated cone, and a truncated pyramid, it is possible to implement superior adsorption and desorption performance compared to a conventional micro LED transfer device, and in particular, it is possible to provide a micro LED transfer device (1) that is capable of adsorption and desorption even in a humid environment or in water.

[0070] That is, in the case of the present invention, the support part (20a) and the adsorption part (20b) have a structure in which the inside is hollow, and the adsorption part (20b) has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid. Therefore, in the case of the adsorption part (20b) having a structure of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid, the lower part is spread out, so that the adsorption force can be excellent when adsorbing a micro LED.

[0071] The materials of the above hollow support (20a) and the adsorption portion (20b) may be the same material or different materials.

[0072] The Young's modulus of the above adsorption portion (20b) may be smaller than the Young's modulus of the above hollow support portion (20a).

[0073] The Young's modulus of the above adsorption part (20b) is smaller than the Young's modulus of the above hollow support part (20a), and the adsorption part (20b) has one of the shapes of a truncated cone, an elliptical truncated cone, and a truncated pyramid, so that the adsorption force can be excellent when adsorbing a micro LED.

[0074] As an example, the adsorption part (20b) may have a Young's modulus of 10 MPa or less. That is, it may be desirable to implement the adsorption part (20b) with a soft material having a Young's modulus of 10 MPa or less in order to improve the adsorption force when adsorbing micro LEDs. The adsorption part (20b) may be manufactured using a material whose Young's modulus can be adjusted to 10 MPa or less, and for example, the adsorption part (20b) may include a polymer hydrogel.

[0075] The material of the hollow support (20a) is not particularly limited, and may be manufactured from a photocurable composition including, for example, polyurethane acrylate (PUA) and 2-hydroxyethyl methacrylate (HEMA).

[0076] When the above adsorption part (20b) is made of a material including a polymer hydrogel, the adsorption part (20b) has a soft characteristic, whereas the hollow support part (20a) may have a different characteristic from the adsorption part (20b) because it is made of a photocurable composition including polyurethane acrylate (PUA) and 2-hydroxyethyl methacrylate (HEMA).

[0077] According to one embodiment of the present invention, when the adsorption part (20b) is made of a material including a polymer hydrogel, the adsorption part (20b) may further include a pH-sensitive material, or the adsorption part (20b) may further include a temperature-sensitive material.

[0078] The above pH-sensitive material is not particularly limited, and any material whose Young's modulus changes when the pH is changed by adding acid dropwise can be used, and an example of this is acrylic acid.

[0079] The above temperature-sensitive material is not particularly limited, and any material whose Young's modulus changes when the temperature increases by heating can be used, and for example, it can be NIPAAm (poly N-isopropylacrylamide).

[0080] When the above adsorption part (20b) further contains acrylic acid, as a pH-sensitive hydrogel, acid is added dropwise during desorption after micro LED adsorption, thereby changing the pH and increasing the Young's modulus of the adsorption part (20b), thereby inducing spontaneous desorption.

[0081] When the above adsorption part (20b) further includes NIPAAm (poly N-isopropylacrylamide), poly(N-isopropylacrylamide) (NIPAAm) that swells at low temperatures and shrinks at high temperatures is added, and when the adsorption part (20b) is heated during desorption after micro LED adsorption, the Young's modulus of the adsorption part (20b) increases, thereby inducing spontaneous desorption.

[0082] The structure (20) including the hollow support (20a) and the adsorption portion (20b) may include at least one shape memory polymer selected from the group consisting of polynorbornene, polyurethane, trans-polyisoprene, styrene-butadiene copolymer, poly(ε-caprolactone), polycyclooctene, polyethylene glycol, liquid crystal polyester, liquid crystal elastomer, and polyethylene.

[0083] In particular, according to one embodiment of the present invention, when the structure (20) is manufactured from a shape memory polymer material, the adsorption portion (20b) of the micro LED transfer device (1) adsorbs the micro LED in a radially expanded state, and after transfer, the adsorption portion (20b) is returned to its original shape by heating, thereby allowing spontaneous detachment to occur.

[0084] In addition, according to one embodiment of the present invention, in the process of lifting a hollow structure (20) including an adsorption portion (20b) having a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid after attaching a micro LED transfer device (1) to the micro LED, an adsorption force can be generated by a pressure difference between the inside and the outside of the hollow structure, so that adsorption and desorption of the micro LED can be freely controlled.

[0085] In particular, a micro LED transfer device (1) capable of adsorption and desorption even in a humid environment or in water can be provided.

[0086]

[0087] FIG. 2 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a second embodiment of the present invention.

[0088] Referring to FIG. 2, in a micro LED transfer device (1) having a structure according to the second embodiment of the present invention, a solid material (30) can be filled in the hollow support (20a).

[0089] As described above, in the process of pressurizing to adsorb the micro LED, which is the object to be adsorbed, there may be a problem of the hollow support (20a) buckling, and to prevent this, the hollow support (20a) may be filled with a solid material (30).

[0090] The solid material (30) filled in the above hollow support (20a) is not particularly limited, and the same material as the material of the support (20a) may be used to prevent buckling.

[0091] When the solid material is filled into the hollow support (20a) as described above, the structure (20) having an internally hollow structure does not have the problem of buckling during the process of absorbing the micro LED, so the micro LED can be stably transferred to the target substrate.

[0092]

[0093] FIG. 3 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a third embodiment of the present invention.

[0094] Referring to FIG. 3, in a micro LED transfer device (1) having a structure according to the third embodiment of the present invention, the height of the hollow support (20a) may be 40% or more and 80% or less of the total height of the hollow structure (20).

[0095] When the height of the hollow support member (20a) satisfies a range of 40% to 80% of the total height of the hollow structure (20), the adsorption and desorption of the micro LED can be freely controlled in the transfer process of the micro LED using the micro LED transfer device (1).

[0096] In particular, a micro LED transfer device (1) capable of adsorption and desorption even in a humid environment or in water can be provided.

[0097] When the height of the hollow support member (20a) is less than 40% of the total height of the hollow structure (20), the height of the adsorption member (20b) becomes 60% or more of the total height of the structure (20), and thus the adsorption member (20b) may not be adsorbed due to buckling.

[0098] On the other hand, if the hollow support (20a) exceeds 80% of the total height of the hollow structure (20), the height of the adsorption part (20b) is too low to adsorb the micro LED with sufficient adsorption force.

[0099] Specifically, according to the third embodiment of the present invention, when the height of the hollow support member (20a) is manufactured to be large within the above range in a structure (20) having the shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid, there is an advantage in that it can be easily detached when a shear force is applied.

[0100]

[0101] FIG. 4 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a fourth embodiment of the present invention.

[0102] Referring to Fig. 4, in a micro LED transfer device (1) including a hollow structure (20') having a hollow support (20a') and an adsorption part (20b') with an interior that is empty, the adsorption part (20b') may have a triangular pyramidal structure and may have a triangular planar shape. That is, when the planar shape of the adsorption part (20b') is triangular, the adsorption and desorption of the micro LED transfer device (1) can be controlled.

[0103] In particular, when the plane shape of the above-mentioned adsorption part (20b') is triangular, detachment occurs easily from the pointed side, whereas detachment is difficult when detached from the opposite side, so there is an effect that detachment can be controlled depending on the detachment direction.

[0104]

[0105] FIG. 5 is a schematic diagram (a) and a cross-sectional view (b) showing a micro LED transfer device having a structure according to a fifth embodiment of the present invention.

[0106] Referring to Fig. 5, in a micro LED transfer device (1) including a hollow structure (20'') having a hollow support (20a'') and an adsorption part (20b'') with an interior that is empty, the adsorption part (20b'') has an elliptical cone structure and may have an elliptical plane shape. When the plane shape of the adsorption part (20b'') is elliptical, the adsorption and desorption of the micro LED transfer device (1) can be controlled.

[0107] In particular, when the plane shape of the above-mentioned adsorption part (20b'') is oval, since the widths of the long and short axes are different, there is an effect that allows for control of the detachment depending on the direction. That is, if detachment is performed first in the direction of the short axis where the width is small, detachment occurs easily, whereas if detachment is performed in the direction of the long axis where the width is large, detachment is difficult, so an effect that allows for control of the detachment depending on the detachment direction can be obtained.

[0108]

[0109] According to one embodiment of the present invention, adsorption and desorption are controlled by adjusting the height of a hollow support in a structure, filling a solid material inside the support of a hollow structure, or depending on the shape of an adsorption portion inlet, thereby enabling transfer of micro LEDs by a micro LED transfer device to proceed without error.

[0110]

[0111] FIG. 6 is a schematic diagram showing a micro LED transfer device having a structure according to a sixth embodiment of the present invention.

[0112] Referring to FIG. 6, in a micro LED transfer device (1) having a structure according to the sixth embodiment of the present invention, a through hole (c) connected to the hollow support (20a) may be arranged in the substrate (10).

[0113] In addition, according to the sixth embodiment of the present invention, a pressure control unit (40) that is connected to the through hole (c) and can control the pressure inside the hollow structure (20) may be further arranged on the other side facing the one side of the substrate (10) on which the hollow structure (20) is arranged.

[0114] The pressure control unit (40) capable of controlling the pressure inside the hollow structure (20) is not particularly limited, and any device or means capable of pressurizing or depressurizing may be used without limitation. For example, as in the sixth embodiment of the present invention, the pressure control unit (40) may include a chamber (40a) arranged on the other side of the substrate (10) through which a fluid such as air or water, which can be used to pressurize or depressurize the inside of the hollow structure (20), can move, and a pressure regulator (40b) connected to the chamber (40a) to provide a fluid such as air or water to and from the inside and outside of the hollow structure (20) from the outside.

[0115] The above pressure regulator (40b) is not particularly limited as long as it can provide a fluid such as air or water, and for example, an air compressor or pump may be used.

[0116] A method of depressurizing or pressurizing using the above pressure regulator (40b) can be applied to a generally known depressurizing or pressurizing process.

[0117] By changing the pressure inside the hollow structure (20) using the pressure control unit (40), the adsorption unit (20b) can be adsorbed and desorbed. Specifically, by reducing the pressure in the pressure control unit (40) as in suction, the micro LED can be adsorbed more quickly. In addition, by applying pressure in the pressure control unit (40), the micro LED can be desorbed more quickly.

[0118]

[0119] Fig. 7 is a schematic diagram showing a micro LED transfer device having a structure according to the seventh embodiment of the present invention.

[0120] Referring to FIG. 7, a micro LED transfer device (1) having a structure according to the seventh embodiment of the present invention is characterized in that a valve (v) that operates by an external signal is further arranged in a pressure control unit (40) that adsorbs and desorbs the adsorption unit (20b) in the micro LED transfer device (1) according to the sixth embodiment.

[0121] The micro LED transfer device (1) having a structure according to the seventh embodiment of the present invention has a valve (v) that operates by an external signal further disposed within the chamber (40a) among the pressure control units (40) that adsorb and desorb the adsorption unit (20b), so that the through hole (c) at a desired position can be opened or closed by an external signal.

[0122] As described above, the process of opening or closing the through hole (c) at a desired location by an external signal can be performed by sending a signal to the valve (v) from a control unit (not shown) connected to the valve (v), and the method of operating the valve (v) through the control unit can follow a generally applied operating method.

[0123] As an example, when the valve (v) is closed, the micro LED transfer device (1) adsorbs the micro LED, and when the valve (v) is opened, pressure is applied to discharge a fluid such as air or water in the direction of the structure through the through hole (c) from the micro LED transfer device (1), thereby detaching the micro LED.

[0124]

[0125] According to another embodiment of the present invention, a method for manufacturing a micro LED transfer device is provided, comprising: manufacturing a mold having a groove formed for forming a hollow structure; filling a first material to a certain extent in the groove of the mold; additionally filling a second material in the groove of the mold; attaching and curing a substrate to cover the groove of the mold; and separating the cured structure in the groove of the mold from the mold, wherein the cured first material forms an adsorption portion, the cured second material forms a hollow support portion, and the hollow structure has an internally hollow structure including a hollow support portion protruding from the substrate and fixed to the substrate and an adsorption portion disposed below the hollow support portion and exposed to the outside, wherein the adsorption portion has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

[0126]

[0127] A method for manufacturing a micro LED transfer device according to another embodiment of the present invention first includes a step of manufacturing a mold in which a groove for forming a hollow structure is formed.

[0128] The step of manufacturing a mold with grooves formed for forming the above-mentioned hollow structure is to manufacture a mold with grooves formed for replicating the hollow structure using a material such as polydimethylsiloxane (PDMS) or Ecoflex.

[0129] Next, a step of filling a certain portion of the groove of the mold with a first material and a step of additionally filling the groove of the mold with a second material are performed.

[0130] The first material and the second material may be the same material or different materials.

[0131] When the first material and the second material are different materials, partial curing can be performed in the step of filling a certain portion of the groove of the mold with the first material as described above, and then a step of additionally filling the groove of the mold with the second material is performed.

[0132] Meanwhile, if the first material and the second material are the same material, the first and second materials may be shape memory polymer materials.

[0133] When the first and second materials are shape memory polymer materials, the step is performed as a process of filling the grooves of the mold with the shape memory polymer material.

[0134] The shape memory polymer material may be at least one selected from the group consisting of polynorbornene, polyurethane, trans-polyisoprene, styrene-butadiene copolymer, poly(ε-caprolactone), polycyclooctene, polyethylene glycol, liquid crystal polyester, liquid crystal elastomer, and polyethylene, but is not necessarily limited thereto.

[0135] The groove of the mold filling the first material may have any one of a truncated cone, an elliptical truncated cone, and a prism, and the groove of the mold filling the second material may have any one of a cylindrical shape, an elliptical cylindrical shape, and a prism, and the hardened first material forms an adsorption portion, and the hardened second material forms a hollow support portion.

[0136] Next, a step of attaching and curing a substrate to cover the groove of the mold and a step of separating the substrate and the structure protrudingly arranged on the substrate from the mold are performed, thereby manufacturing a micro LED transfer device.

[0137] The above structure has an internally hollow structure including a hollow support portion protruding from the substrate and fixed to the substrate and an adsorption portion positioned below the hollow support portion and exposed to the outside, wherein the adsorption portion has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid.

[0138]

[0139] FIG. 8 is a schematic diagram showing a micro LED transfer method using a micro LED transfer device having a structure according to the first embodiment of the present invention.

[0140] Referring to FIG. 8, another embodiment of the present invention provides a micro-LED transfer method using a micro-LED transfer device, including the steps of forming a micro-LED (200) on a wafer (100), attaching the micro-LED transfer device (1) to the micro-LED (200), adsorbing the micro-LED (200) and detaching it from the wafer (100), transferring the micro-LED (200) adsorbed on the micro-LED transfer device to another substrate (300), and detaching the micro-LED (200) from the micro-LED transfer device, wherein the step of attaching the micro-LED transfer device (1) to the micro-LED (200) is performed by radially expanding the adsorption portion (20b) of the micro-LED transfer device (1).

[0141] A micro LED transfer method using a micro LED transfer device according to one embodiment of the present invention first forms a micro LED (200) on a wafer (100), and then a step of placing the micro LED transfer device (1) on the wafer (100) and applying heat to attach it to the micro LED (200) is performed.

[0142] When the above micro LED transfer device (1) is placed on the wafer (100) and pressurized, the adsorption portion (20b) of the structure (20) expands radially on the surface of the micro LED (200) and attaches, so strong adsorption occurs thereafter.

[0143] The micro LED transfer device (1) according to one embodiment of the present invention has the advantage of being able to adsorb micro LED (200) even in a state where moisture is present.

[0144] Next, a step of adsorbing the micro LED (200) and removing it from the wafer (100) is performed.

[0145] According to one embodiment of the present invention, when the micro LED (200) is removed from the wafer (100), even if there is moisture, the suction force between the micro LED transfer device (1) and the micro LED (200) can be maintained.

[0146] Finally, a step of transferring the micro LED (200) attached to the micro LED transfer device (1) to another substrate (300) and a step of detaching the micro LED (200) from the micro LED transfer device (1) are performed.

[0147] The step of transferring the micro LED (200) attached to the micro LED transfer device (1) to another substrate (300) can be performed by positioning the micro LED (200) on a solder ball (400) placed on the other substrate (300) and applying heat to bond them.

[0148] The step of detaching the micro LED (200) from the micro LED transfer device (1) can be performed by causing the adsorption portion (20b) of the micro LED transfer device (1) to return to its original shape by heat applied to bond the micro LED (200) to the other substrate (300).

[0149] That is, according to one embodiment of the present invention, when the hollow structure (20) is made of a shape memory polymer material as described above, the adsorption portion (20b) of the hollow structure (20) expands radially and adsorbs the micro LED (200), so that the adsorption portion (20b) of the micro LED transfer device (1) returns to its original shape due to the heat applied during the desorption process, thereby causing desorption.

[0150]

[0151] FIG. 9 is a schematic diagram showing a micro LED transfer method using a micro LED transfer device having a structure according to the seventh embodiment of the present invention.

[0152] Referring to FIG. 9, in a micro LED transfer method using a micro LED transfer device (1) having a structure according to the seventh embodiment of the present invention, a pressure control unit (40) connected to the through hole (c) of the micro LED transfer device (1) can change the pressure inside a hollow structure (20) to adsorb and desorb the micro LED (200).

[0153] In addition, when the valve (v) is closed, the micro LED transfer device (1) absorbs the micro LED (200), and when the valve (v) is opened, the micro LED (200) can be detached from the micro LED transfer device (1).

[0154] That is, only the micro LED (200) at the desired location can be adsorbed and desorbed through the valve (v) operated by an external signal located within the chamber (40a) among the pressure control units (40) that adsorb and desorb the adsorption unit (20b).

[0155]

[0156] According to one embodiment of the present invention, in the process of lifting a hollow structure including an adsorption portion having a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid, an adsorption force can be generated by a pressure difference between the inside and the outside of the hollow structure, so that the adsorption and desorption of the micro LED can be freely controlled in the transfer process of the micro LED.

[0157] In particular, a micro LED transfer device capable of adsorption and desorption even in a humid environment or in water can be provided.

[0158] In addition, the present invention controls the height of a hollow support in a hollow structure, fills a solid material inside the support of the hollow structure, or controls adsorption and desorption according to the shape of the inlet of the adsorption portion, thereby enabling transfer of micro LEDs by a micro LED transfer device to proceed without error.

[0159]

[0160] The present invention described above is not limited to the above-described embodiments, as various substitutions and changes can be made within the scope of the technical idea of ​​the present invention by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. Description; and A hollow structure protruding and arranged on the above-mentioned substrate; The above hollow structure is, A hollow support member protruding from the above-mentioned substrate and fixed to the substrate; and It is a hollow structure having an interior including an adsorption portion exposed to the outside and placed at the bottom of the hollow support portion; A micro LED transfer device in which the above adsorption part has a shape of any one of a truncated cone, an elliptical truncated cone, and a square truncated cone.

2. In paragraph 1, A micro LED transfer device in which the Young's modulus of the above adsorption portion is smaller than the Young's modulus of the above hollow support portion.

3. In paragraph 1, The hollow structure is a micro LED transfer device comprising at least one shape memory polymer selected from the group consisting of polynorbornene, polyurethane, trans-polyisoprene, styrene-butadiene copolymer, poly(ε-caprolactone), polycyclooctene, polyethylene glycol, liquid crystal polyester, liquid crystal elastomer, and polyethylene.

4. In paragraph 1, A micro LED transfer device in which a solid material is filled in the hollow support portion above.

5. In paragraph 1, A micro LED transfer device in which the height of the hollow support is 40% or more and 80% or less of the total height of the hollow structure.

6. In paragraph 1, A micro LED transfer device having a through hole connected to the hollow support part as described above.

7. In paragraph 6, A micro LED transfer device having a pressure control unit further disposed on one side of the substrate opposite to the one side on which the hollow structure is disposed, and connected to the through hole, and capable of controlling the pressure inside the hollow structure.

8. In paragraph 7, A micro LED transfer device further comprising a valve that is operated by an external signal in the above pressure control unit.

9. A step of manufacturing a mold having a groove formed to form a hollow structure; A step of filling a certain portion of the first material into the groove of the mold; A step of additionally filling a second material into the groove of the above mold; A step of attaching and curing a substrate to cover the groove of the mold; and A step of separating the hardened hollow structure from the mold in the groove of the mold; The above-mentioned hardened first material forms an adsorption portion, and the above-mentioned hardened second material forms a hollow support portion, The above hollow structure is, A hollow support portion protruding from the above-mentioned substrate and fixed to the substrate, and an internally hollow structure including an adsorption portion exposed to the outside and disposed below the hollow support portion, wherein the adsorption portion has a shape of any one of a truncated cone, an elliptical truncated cone, and a truncated pyramid. A method for manufacturing a micro LED transfer device.

10. In paragraph 9, A method for manufacturing a micro LED transfer device further comprising a step of partially filling a first material into a groove of the mold and then partially curing the first material.

11. A step of forming a micro LED on a wafer and attaching a micro LED transfer device of any one of claims 1 to 8 to the micro LED; A step of adsorbing the above micro LED and removing it from the wafer; A step of transferring the micro LED absorbed by the micro LED transfer device to another substrate; and A micro LED transfer method using a micro LED transfer device, comprising: a step of detaching the micro LED from the micro LED transfer device; and a step of attaching the micro LED transfer device to the micro LED, wherein the step of attaching the micro LED transfer device to the micro LED is performed by radially expanding the adsorption portion of the micro LED transfer device.

12. In paragraph 11, A micro LED transfer method using a micro LED transfer device, wherein the step of transferring the micro LED attached to the micro LED transfer device to another substrate is performed by positioning the micro LED on a solder ball placed on the other substrate and applying heat to bond the micro LED.

13. In paragraph 12, A micro LED transfer method using a micro LED transfer device, wherein the step of detaching the micro LED from the micro LED transfer device is performed by causing the adsorption portion of the micro LED transfer device to return to its original shape due to the applied heat.

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