Transfer substrate assembly and method for manufacturing display device using the same

Abstract

The present invention can be applied to the technical field related to display devices, for example, to a light emitting diode (LED), a transfer substrate assembly, and a method for manufacturing a display device using the same. Disclosed herein is a transfer substrate assembly for transferring a light emitting device, which may include: a transfer substrate including a first surface on which a rough surface is formed; the bonding layer is locally positioned on the first surface of the transfer substrate; and a light emitting device adhered through the adhesive layer.

Description

Technical Field

[0001] This invention is applicable to display device related technical fields, such as micro LEDs (Light Emitting Diodes), transfer substrate assemblies, and methods for manufacturing display devices using the same. Background Technology

[0002] In recent years, the field of display technology has seen the development of display devices with superior characteristics such as thinness and flexibility. In contrast, the main commercially available displays are currently liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs).

[0003] However, LCDs suffer from issues such as slow response time and difficulty in achieving flexibility, while OLEDs suffer from issues such as short lifespan and poor production yield.

[0004] On the other hand, light-emitting diodes (LEDs), known as semiconductor light-emitting devices that convert electric current into light, have been used since the commercialization of red LEDs using GaAsP compound semiconductors in 1962, along with green LEDs of the GaP:N series, as light sources for displaying images in electronic devices, primarily information and communication equipment. Therefore, a solution can be proposed to solve the aforementioned problems by using semiconductor light-emitting devices to implement displays. Compared to filament-based light-emitting devices, these semiconductor light-emitting devices offer a variety of advantages, including longer lifespan, lower power consumption, superior initial drive characteristics, and higher shock resistance.

[0005] To optimize the electrical properties of the n-type electrodes in LEDs, gold-germanium (AuGe) alloys are typically used due to their low reflectivity. In particular, the reflectivity of AuGe alloys decreases to approximately 20% after heat treatment to form ohmic contacts.

[0006] In an effort to improve this, various metal layer structures were tried, but it was difficult to simultaneously satisfy both electrical and optical properties.

[0007] To address this issue, a configuration was proposed where an ohmic contact is partially formed and a reflective film is formed in the remaining portion. However, due to the micrometer-scale dimensions of the light-emitting device chip, this configuration presents structural challenges.

[0008] In addition, a reflective film covering the entire alloy morphology of an n-type semiconductor layer has been proposed, but its reflectivity is lower than that of a single metal.

[0009] In addition, the gold (Au) reflective film, which is mainly used in red light-emitting devices, has a high manufacturing cost and will interdiffusion with aluminum (Al) used as bridge metal in the display device, resulting in the formation of an inhomogeneous intermetallic compound (IMC).

[0010] The rapid diffusion rate at such Al-Au interfaces can lead to the formation of Kirkendall voids in Au-rich regions. These voids not only reduce the area through which current flows, thus increasing resistance, but also, in the long run, can cause reliability issues.

[0011] Therefore, a solution to this problem is needed. Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The technical problem to be solved by the present invention is to provide a transfer substrate assembly and a method for manufacturing a display device using the same, wherein the transfer substrate assembly can increase the adhesive strength of the adhesive layer that bonds the light-emitting device and the transfer substrate.

[0014] In addition, a transfer substrate assembly and a method for manufacturing a display device using the same are provided, wherein the transfer substrate assembly can ensure sufficient alignment allowance even when using ultra-small light-emitting devices.

[0015] In addition, a transfer substrate assembly and a method for manufacturing a display device using the same are provided, wherein the transfer substrate assembly can also reduce the area of ​​the sacrificial layer used for dispersing light-emitting devices.

[0016] In addition, a transfer substrate assembly and a method for manufacturing a display device using the same are provided. The transfer substrate assembly can reduce the dispersion time of light-emitting devices, thereby improving productivity.

[0017] Furthermore, an objective of one embodiment of the present invention is to address various problems not mentioned herein. Those skilled in the art will understand this from the general gist of the specification and drawings.

[0018] Technical solutions to the problem

[0019] As a first point of view for achieving the stated objective, the present invention discloses a transfer substrate assembly for a transfer light-emitting device, the transfer substrate assembly comprising: a transfer substrate including a first surface having a roughened surface; an adhesive layer partially located on the first surface of the transfer substrate; and a light-emitting device adhered thereto by the adhesive layer.

[0020] As an exemplary embodiment, a sacrificial layer may also be included between the adhesive layer and the light-emitting device.

[0021] As an exemplary embodiment, the width or diameter of the sacrificial layer may be greater than the width or diameter of the adhesive layer.

[0022] As an exemplary embodiment, the width or diameter of the sacrificial layer may be equal to or smaller than the width or diameter of the contact surface of the light-emitting device.

[0023] As an exemplary embodiment, the transfer substrate may be a sapphire substrate.

[0024] As an exemplary embodiment, the rough surface may be a surface formed by wet etching of the first surface of the sapphire substrate.

[0025] As an exemplary embodiment, the rough surface may include a concave-convex pattern that increases the surface area of ​​the first surface of the transfer substrate.

[0026] As a second aspect for achieving the stated objective, the present invention discloses a method for manufacturing a display device including a light-emitting device, the method comprising: a step of forming a sacrificial layer on a single light-emitting device separately disposed on a growth substrate; a step of forming an adhesive layer on the sacrificial layer; a step of adhering the adhesive layer to a first surface of a transfer substrate having a roughened surface; and a step of removing the growth substrate.

[0027] As an exemplary embodiment, the method may further include the steps of removing the sacrificial layer and separating the individual light-emitting device from the first side of the transfer substrate.

[0028] As an exemplary embodiment, the process of removing the sacrificial layer may include the steps of etching the sacrificial layer in a fluid and dispersing the individual light-emitting device into the fluid.

[0029] Invention Effects

[0030] According to one embodiment of the present invention, the following effects are achieved.

[0031] First, according to embodiments of the present invention, since the size of the adhesive layer that bonds the light-emitting device and the transfer substrate can be reduced, sufficient alignment allowance can be ensured even when using ultra-small light-emitting devices.

[0032] In addition, the adhesive layer can have sufficient adhesive strength to ensure adhesion between the light-emitting device and the transfer substrate. This reduces the loss of the light-emitting device during manufacturing.

[0033] Furthermore, due to alignment errors, problems may not occur during dispersion. On the other hand, it is also possible to reduce the area of ​​the sacrificial layer used to disperse the light-emitting device.

[0034] Furthermore, according to embodiments of the present invention, the size of the adhesive layer pattern can be reduced, thereby reducing the size and thickness of the sacrificial layer. Therefore, the dispersion time of the light-emitting device can be reduced. This, in turn, improves productivity.

[0035] Furthermore, according to yet another embodiment of the present invention, additional technical effects not mentioned herein are also present. Those skilled in the art will understand this from the general gist of the specification and drawings. Attached Figure Description

[0036] Figure 1 This is a conceptual diagram illustrating an example of a display device utilizing a semiconductor light-emitting device according to the present invention.

[0037] Figure 2 yes Figure 1 A magnified view of part A.

[0038] Figure 3a and Figure 3b It is along Figure 2 A cross-sectional view cut by lines BB and CC.

[0039] Figure 4 This is a conceptual diagram illustrating the flip-chip semiconductor light-emitting device shown in Figure 3.

[0040] Figures 5a to 5c This is a conceptual diagram illustrating various forms of color realization in relation to flip-chip semiconductor light-emitting devices.

[0041] Figure 6 This is a cross-sectional view illustrating an example of a method for manufacturing a display device utilizing a semiconductor light-emitting device according to the present invention.

[0042] Figure 7 This is a perspective view showing another example of a display device utilizing a semiconductor light-emitting device according to the present invention.

[0043] Figure 8 It is along Figure 7 A cross-sectional view cut by line DD.

[0044] Figure 9 It is shown Figure 8 A conceptual diagram of a vertical semiconductor light-emitting device.

[0045] Figures 10 to 14 This is a cross-sectional view illustrating a portion of the manufacturing process of a display device including a light-emitting device according to an embodiment of the present invention.

[0046] Figure 15 This is a photograph showing a portion of a transfer substrate assembly according to an embodiment of the present invention.

[0047] Figure 16 It is Figure 15 An enlarged photograph of part A.

[0048] Figure 17 This is a cross-sectional view showing the state of individual light-emitting devices dispersed during the manufacturing process of a display device including light-emitting devices according to an embodiment of the present invention.

[0049] Figure 18 This is a diagram illustrating the alignment allowance of the transfer substrate assembly of the comparative example and the transfer substrate assembly of the embodiment of the present invention.

[0050] Figure 19 This is a photograph showing the state in which a light-emitting device is bonded to a transfer substrate in a comparative example.

[0051] Figure 20 This is a photograph showing the state in which a light-emitting device is bonded to a transfer substrate in an embodiment of the present invention.

[0052] Figure 21 and Figure 22 This is a schematic diagram illustrating the manufacturing process of a display device according to an embodiment of the present invention.

[0053] Figure 23 This is a cross-sectional view illustrating a display device according to an embodiment of the present invention. Detailed Implementation

[0054] The embodiments disclosed in this specification will now be described in detail with reference to the accompanying drawings. Regardless of the drawing numbers, the same or similar constituent elements are given the same reference numerals, and repeated descriptions of them are omitted. The suffixes "module" and "part" used for constituent elements in the following description are assigned or used interchangeably for ease of writing and do not inherently have a distinguishing meaning or function. Furthermore, in describing the embodiments disclosed in this invention, detailed descriptions of relevant prior art are omitted when it is determined that a specific description of such prior art would obscure the essence of the disclosed embodiments. Moreover, it should be understood that the accompanying drawings are only for aiding understanding of the embodiments disclosed in this specification and should not be construed as limiting the technical ideas disclosed in this specification to the drawings.

[0055] Furthermore, although the accompanying drawings are described separately for ease of explanation, those skilled in the art can also implement other embodiments by combining at least two or more drawings, which also falls within the scope of the present invention.

[0056] Additionally, it should be understood that when referring to elements such as layers, regions, or substrates as being "on" different constituent elements, it means either directly on top of other elements or that there may be an intermediate element between them.

[0057] The display device described in this specification is a concept encompassing all display devices that display information per unit pixel or set of units pixels. Therefore, it is not limited to finished products but can also apply to components. For example, the panel itself, which is equivalent to a component of a digital TV, is also equivalent to the display device described in this specification. Finished products may include mobile phones, smartphones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation devices, Slate PCs, tablet PCs, Ultrabooks, digital TVs, desktop computers, etc.

[0058] However, it will be apparent to those skilled in the art that the configuration of the embodiments described in this specification can also be applied to displayable devices of new product forms developed in the future.

[0059] The semiconductor light-emitting devices mentioned in this manual include concepts such as LED and micro LED, which can be used interchangeably.

[0060] Figure 1 This is a conceptual diagram illustrating an example of a display device utilizing a semiconductor light-emitting device according to the present invention.

[0061] like Figure 1 As shown, the information processed in the control unit (not shown) of the display device 100 can be displayed using a flexible display.

[0062] Flexible displays include, for example, displays that can be bent, folded, twisted, or rolled up by external force.

[0063] Furthermore, a flexible display can be, for example, a display manufactured on a thin and flexible substrate that can be bent, folded, or rolled up like paper, while retaining the display characteristics of an existing flat panel display.

[0064] In its unbent state (e.g., with an infinitely large radius of curvature, hereinafter referred to as the first state), the display area of ​​a flexible display is planar. When it changes from the first state to a bent state due to external force (e.g., with a finite radius of curvature, hereinafter referred to as the second state), the display area can become a curved surface. Figure 1 As shown, the information displayed in the second state can be visual information output onto the curved surface. This visual information is achieved by independently controlling the emission of unit pixels (sub-pixels) configured in a matrix. Here, a unit pixel refers to, for example, the smallest unit used to implement a color.

[0065] The unit pixel of this flexible display can be realized by a semiconductor light-emitting device. As one type of semiconductor light-emitting device that converts electric current into light, a light-emitting device is described as an example in this invention. A light-emitting diode (LED) can be cited as an example of a light-emitting device. This LED can be formed in a small size, thus enabling it to function as a unit pixel even in the second state.

[0066] The following describes in detail, with reference to the accompanying drawings, a flexible display implemented using such light-emitting diodes.

[0067] Figure 2 yes Figure 1 A magnified view of part A.

[0068] Figure 3a and Figure 3b It is along Figure 2 A cross-sectional view cut by lines BB and CC.

[0069] like Figure 2 , Figure 3a as well as Figure 3b As shown, the display device 100 utilizing semiconductor light-emitting devices exemplifies a display device 100 using a passive matrix (PM) semiconductor light-emitting device. However, the examples described below can also be applied to semiconductor light-emitting devices using an active matrix (AM) method.

[0070] like Figure 2 As shown, the display device 100 includes a substrate 110, a first electrode 120, a conductive adhesive layer 130, a second electrode 140, and at least one semiconductor light-emitting device 150.

[0071] The substrate 110 can be a flexible substrate. For example, to realize a flexible display device, the substrate 110 can contain glass or polyimide (PI). Alternatively, any material with insulating and flexible properties can be used, such as PEN (Polyethylene Naphthalate), PET (Polyethylene Terephthalate), etc. Furthermore, the substrate 110 can be either transparent or opaque.

[0072] The substrate 110 may be a wiring substrate on which the first electrode 120 is disposed, and therefore the first electrode 120 may be located on the substrate 110.

[0073] like Figure 3a As shown, the insulating layer 160 can be disposed on the substrate 110 on which the first electrode 120 is provided, and the auxiliary electrode 170 can be located on the insulating layer 160. In this case, the state in which the insulating layer 160 is stacked on the substrate 110 can become a wiring substrate. More specifically, the insulating layer 160 can be made of an insulating and flexible material, such as polyimide (PI), PET, PEN, etc., and can be integrally formed with the substrate 110 to form a substrate.

[0074] The auxiliary electrode 170, serving as an electrode electrically connecting the first electrode 120 to the semiconductor light-emitting device 150, is located on the insulating layer 160 and configured correspondingly to the position of the first electrode 120. For example, the auxiliary electrode 170 is dot-shaped and can be electrically connected to the first electrode 120 through an electrode hole 171 penetrating the insulating layer 160. The electrode hole 171 can be formed by filling the through-hole with a conductive material.

[0075] like Figure 2 or Figure 3a As shown, although a conductive adhesive layer 130 is formed on one side of the insulating layer 160, the present invention is not necessarily limited to this. For example, a layer performing a specific function may be formed between the insulating layer 160 and the conductive adhesive layer 130, or the conductive adhesive layer 130 may be disposed on the substrate 110 without the insulating layer 160. In the structure where the conductive adhesive layer 130 is disposed on the substrate 110, the conductive adhesive layer 130 can function as an insulating layer.

[0076] The conductive adhesive layer 130 can be a layer that is both adhesive and conductive. Therefore, conductive and adhesive substances can be mixed in the conductive adhesive layer 130. In addition, since the conductive adhesive layer 130 is malleable, flexible functionality can be achieved in the display device.

[0077] As an example, the conductive adhesive layer 130 can be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, etc. The conductive adhesive layer 130 can be configured to allow electrical interconnection in the Z direction throughout its thickness, while being electrically insulating in the horizontal XY direction. Therefore, the conductive adhesive layer 130 can be named a Z-axis conductive layer (however, hereinafter referred to as "conductive adhesive layer").

[0078] The anisotropic conductive film, as a film in the form of an anisotropic conductive medium mixed in an insulating substrate, becomes conductive only in specific portions due to the anisotropic conductive medium when heat and / or pressure are applied. Although the following description assumes heat and / or pressure is applied to the anisotropic conductive film, other methods can be applied to make the anisotropic conductive film locally conductive. For example, other methods described above could include applying only either heat or pressure, or UV curing, etc.

[0079] Additionally, for example, the anisotropic conductive medium can be conductive spheres or conductive particles. For instance, an anisotropic conductive film, as a film in the form of conductive spheres mixed in an insulating matrix, becomes conductive only in specific portions due to the conductive spheres when heat and / or pressure are applied. Anisotropic conductive films can also be in a state containing a plurality of particles, where the particles are cores of conductive material encapsulated by an insulating film of polymer material. In this case, as the insulating film in the portion subjected to heat and pressure is disrupted, the core becomes conductive. At this point, the core's shape deforms, potentially forming layers that are in contact with each other in the thickness direction of the film. As a more specific example, applying heat and pressure to the entire anisotropic conductive film results in localized electrical connections in the Z-axis direction due to the height difference between the opposing elements bonded by the anisotropic conductive film.

[0080] As another example, an anisotropic conductive film can be in the form of a plurality of particles, which are formed by an insulating core coated with a conductive material. In this case, the conductive material in the portion subjected to heat and pressure deforms (presses and adheres), becoming conductive along the thickness direction of the film. As another example, it can also be shaped such that the conductive material penetrates the insulating substrate along the Z-axis, thus becoming conductive along the thickness direction of the film. In this case, the conductive material can have a pointed tip.

[0081] Anisotropic conductive films can be fixed array anisotropic conductive films (ACFs) formed by inserting conductive spheres into one side of an insulating substrate. More specifically, the insulating substrate is formed of an adhesive material, and the conductive spheres are concentrated at the bottom of the insulating substrate. If heat or pressure is applied to the substrate, the spheres deform together with the conductive spheres and become conductive in the vertical direction.

[0082] However, the present invention is not limited thereto. The anisotropic conductive film may be in the form of conductive spheres randomly mixed in an insulating substrate, or it may be configured as a plurality of layers with conductive spheres arranged in one layer (double-ACF, double-layer ACF), etc.

[0083] Anisotropic conductive pastes, as a combination of paste and conductive spheres, can be pastes in which conductive spheres are mixed into an insulating and adhesive base material. Alternatively, solutions containing conductive particles can be solutions containing conductive particles or nanoparticles.

[0084] Refer again Figure 3a The second electrode 140 is located on the insulating layer 160 in a state separate from the auxiliary electrode 170. That is, the conductive adhesive layer 130 is disposed on the insulating layer 160 where the auxiliary electrode 170 and the second electrode 140 are located.

[0085] With the auxiliary electrode 170 and the second electrode 140 located in the insulating layer 160, after forming the conductive adhesive layer 130, if the semiconductor light-emitting device 150 is connected in a flip-chip configuration by applying heat and pressure, then the semiconductor light-emitting device 150 is electrically connected to the first electrode 120 and the second electrode 140.

[0086] Figure 4 This is a conceptual diagram illustrating the flip-chip semiconductor light-emitting device shown in Figure 3.

[0087] Reference Figure 4 Semiconductor light-emitting devices can be flip-chip type light-emitting devices.

[0088] For example, the semiconductor light-emitting device includes: a p-type electrode 156, a p-type semiconductor layer 155 for forming the p-type electrode 156, an active layer 154 formed on the p-type semiconductor layer 155, an n-type semiconductor layer 153 formed on the active layer 154, and an n-type electrode 152 disposed horizontally on the n-type semiconductor layer 153, separate from the p-type electrode 156. In this case, the p-type electrode 156 can be connected to the conductive adhesive layer 130. Figure 3a and Figure 3b The auxiliary electrode 170 shown is electrically connected, and the n-type electrode 152 can be electrically connected to the second electrode 140.

[0089] Refer again Figure 2 , Figure 3a as well as Figure 3b The auxiliary electrode 170 is formed elongated in one direction, so that one auxiliary electrode can be electrically connected to a plurality of semiconductor light-emitting devices 150. For example, the p-type electrodes of the semiconductor light-emitting devices on the left and right sides centered on the auxiliary electrode can be electrically connected to one auxiliary electrode.

[0090] More specifically, due to heat and pressure, the semiconductor light-emitting device 150 is pressed into the conductive adhesive layer 130. This makes only the portion between the p-type electrode 156 and the auxiliary electrode 170, and the portion between the n-type electrode 152 and the second electrode 140 of the semiconductor light-emitting device 150 conductive. The remaining portions are non-conductive because no semiconductor light-emitting device is pressed into them. Thus, the conductive adhesive layer 130 not only bonds the semiconductor light-emitting device 150 to the auxiliary electrode 170 and to the second electrode 140, but also forms an electrical connection.

[0091] In addition, a plurality of semiconductor light-emitting devices 150 constitute a light-emitting device array, and a phosphor layer 180 is formed on the light-emitting device array.

[0092] The light-emitting device array may include a plurality of semiconductor light-emitting devices with different brightness values. Each semiconductor light-emitting device 150 constitutes a unit pixel and is electrically connected to a first electrode 120. For example, there may be a plurality of first electrodes 120, such as the plurality of semiconductor light-emitting devices may be configured in several columns, and each column of semiconductor light-emitting devices may be electrically connected to any one of the plurality of first electrodes.

[0093] Furthermore, since the plurality of semiconductor light-emitting devices are connected in a flip-chip configuration, it is possible to utilize a plurality of semiconductor light-emitting devices grown on a transparent dielectric substrate. Additionally, the plurality of semiconductor light-emitting devices can be, for example, nitride semiconductor light-emitting devices. Because the semiconductor light-emitting device 150 possesses excellent brightness, even a small size can constitute a single unit pixel.

[0094] like Figure 3a and Figure 3b As shown, partition walls 190 can be provided between the semiconductor light-emitting devices 150. In this case, the partition walls 190 can serve to separate individual unit pixels from each other and can be integrated with the conductive adhesive layer 130. For example, the semiconductor light-emitting devices 150 can be inserted into an anisotropic conductive film, with the substrate of the anisotropic conductive film forming the partition walls.

[0095] In addition, if the substrate of the anisotropic conductive film is black, then even without an additional black insulator, the separator 190 can have reflective properties while increasing contrast.

[0096] As another example, a reflective partition wall may be additionally provided as partition wall 190. In this case, depending on the purpose of the display device, partition wall 190 may include a black or white insulator. When using a partition wall with a white insulator, it can have the effect of improving reflectivity, while when using a partition wall with a black insulator, it can have reflective properties while increasing contrast.

[0097] The phosphor layer 180 may be located on the outer surface of the semiconductor light-emitting device 150. For example, the semiconductor light-emitting device 150 is a blue semiconductor light-emitting device that emits blue B light, and the phosphor layer 180 performs the function of converting the blue B light into the hue of a unit pixel. The phosphor layer 180 may be a red phosphor 181 or a green phosphor 182 constituting a single pixel.

[0098] That is, at the location constituting a red unit pixel, a red phosphor 181 capable of converting blue light into red (R) light can be stacked on a blue semiconductor light-emitting device; at the location constituting a green unit pixel, a green phosphor 182 capable of converting blue light into green (G) light can be stacked on a blue semiconductor light-emitting device. Alternatively, for the portion constituting a blue unit pixel, only a blue semiconductor light-emitting device can be used. In this case, red (R), green (G), and blue (B) unit pixels can constitute one pixel. More specifically, a phosphor of one hue can be stacked along each line of the first electrode 120. Therefore, in the first electrode 120, one line can be an electrode controlling one hue. That is, along the second electrode 140, red (R), green (G), and blue (B) can be sequentially arranged, thereby realizing a unit pixel.

[0099] However, the present invention is not limited thereto, and alternative phosphors can be achieved by combining semiconductor light-emitting devices 150 and quantum dots (QDs) to realize unit pixels of red (R), green (G), and blue (B).

[0100] In addition, to improve contrast, a black matrix 191 can be arranged between the individual phosphor layers. That is, this black matrix 191 can improve the contrast between light and dark areas.

[0101] However, the present invention is not limited thereto, and other structures for realizing blue, red, and green can also be used.

[0102] Figures 5a to 5cThis is a conceptual diagram illustrating various forms of color realization in relation to flip-chip semiconductor light-emitting devices.

[0103] Reference Figure 5a Each semiconductor light-emitting device 150 can be made into a high-output light-emitting device that emits a variety of colors of light, including blue, by adding indium (In) and / or aluminum (Al) along with gallium nitride (GaN) as the main material.

[0104] In this case, to form a unit pixel (sub-pixel), the semiconductor light-emitting device 150 can be a red (R), green (G), and blue (B) semiconductor light-emitting device, respectively. For example, red R, green G, and blue B semiconductor light-emitting devices are arranged alternately, and a pixel is formed based on the red, green, and blue unit pixels of the red, green, and blue semiconductor light-emitting devices, thereby realizing a full-color display.

[0105] Reference Figure 5b The semiconductor light-emitting device 150a can be provided with a white light-emitting device W in which each element has a yellow phosphor layer. In this case, in order to form a unit pixel, a red phosphor layer 181, a green phosphor layer 182, and a blue phosphor layer 183 can be provided on the white light-emitting device W. In addition, on this white light-emitting device W, repeating red, green, and blue color filters can be used to form a unit pixel.

[0106] Reference Figure 5c The semiconductor light-emitting device 150b may also have a structure in which a red phosphor layer 184, a green phosphor layer 185, and a blue phosphor layer 186 are provided on the ultraviolet light-emitting device UV. As described above, the semiconductor light-emitting device can use visible light to ultraviolet light (UV) throughout the entire area, and can be extended to a form of semiconductor light-emitting device that can use ultraviolet light (UV) as an excitation source for the upper phosphor.

[0107] Referring again to this example, the semiconductor light-emitting device is located on the conductive adhesive layer, forming a unit pixel in the display device. Because semiconductor light-emitting devices have excellent brightness, even small sizes can form a single unit pixel.

[0108] For example, the dimensions of individual semiconductor light-emitting devices 150, 150a, 150b of this type can be, for example, rectangular or quadrilateral elements with a side length of 80 μm or less. If rectangular, the dimensions can be 20 × 80 μm or less.

[0109] Furthermore, even when using regular quadrilateral semiconductor light-emitting devices 150, 150a, and 150b with a single side length of 10 μm as unit pixels, sufficient brightness can be displayed to construct a display device.

[0110] Therefore, taking a rectangular pixel with a unit pixel size of 600μm on one side and 300μm on the other side as an example, the spacing between semiconductor light-emitting devices 150, 150a, and 150b is relatively large.

[0111] Therefore, under these circumstances, it is possible to achieve a flexible display device with high image quality of HD or higher.

[0112] The display device utilizing a semiconductor light-emitting device described above can be manufactured using a novel manufacturing method. Hereinafter, refer to... Figure 6 The manufacturing method is explained.

[0113] Figure 6 This is a cross-sectional view illustrating an example of a method for manufacturing a display device utilizing a semiconductor light-emitting device according to the present invention.

[0114] like Figure 6 As shown, firstly, a conductive adhesive layer 130 is formed on the insulating layer 160 where the auxiliary electrode 170 and the second electrode 140 are located. The insulating layer 160 is then stacked on the first substrate 110 to form a substrate (or wiring substrate), on which the first electrode 120, the auxiliary electrode 170, and the second electrode 140 are disposed. In this case, the first electrode 120 and the second electrode 140 can be arranged in mutually orthogonal directions. Furthermore, to realize a flexible display device, the first substrate 110 and the insulating layer 160 can each comprise glass or polyimide (PI).

[0115] For example, the conductive adhesive layer 130 can be implemented by an anisotropic conductive film, for which an anisotropic conductive film can be coated on the substrate where the insulating layer 160 is located.

[0116] Then, the second substrate 112, on which a plurality of semiconductor light-emitting devices 150, corresponding to the positions of the auxiliary electrode 170 and the second electrode 140 and constituting a single pixel, are located, is configured such that the semiconductor light-emitting devices 150 face the auxiliary electrode 170 and the second electrode 140.

[0117] In this case, the second substrate 112, as the growth substrate for growing the semiconductor light-emitting device 150, can be a sapphire substrate or a silicon substrate.

[0118] When the semiconductor light-emitting device is formed on a wafer basis, it can be effectively used in a display device by having the spacing and size required to form a display device.

[0119] Then, the wiring substrate and the second substrate 112 are hot-pressed. For example, the wiring substrate and the second substrate 112 can be hot-pressed using an ACF indenter. Through hot pressing, the wiring substrate and the second substrate 112 are bonded together. Due to the characteristics of the anisotropic conductive film, only the portions between the semiconductor light-emitting device 150 and the auxiliary electrode 170 and between the semiconductor light-emitting device 150 and the second electrode 140 are conductive, thereby allowing the electrodes and the semiconductor light-emitting device 150 to be electrically connected. At this time, the semiconductor light-emitting device 150 is inserted into the interior of the anisotropic conductive film, thereby forming a partition wall between the semiconductor light-emitting devices 150.

[0120] Then, the second substrate 112 is removed. For example, the second substrate 112 can be removed using laser lift-off (LLO) or chemical lift-off (CLO).

[0121] Finally, the semiconductor light-emitting device 150 is exposed to the outside by removing the second substrate 112. If necessary, a transparent insulating layer (not shown) can be formed by coating silicon oxide (SiOx) or the like on the wiring substrate on which the semiconductor light-emitting device 150 is bonded.

[0122] Additionally, the process may include a step of forming a phosphor layer on one side of the semiconductor light-emitting device 150. For example, if the semiconductor light-emitting device 150 is a blue semiconductor light-emitting device that emits blue B light, a red or green phosphor for converting this blue B light into a hue per unit pixel may be formed on one side of the blue semiconductor light-emitting device.

[0123] The manufacturing method or structure of the display device utilizing semiconductor light-emitting devices described above can be modified in various ways. For example, a vertical semiconductor light-emitting device can also be used in the display device described above.

[0124] Furthermore, in the variations or embodiments described below, the same or similar reference numerals are given to the same or similar configurations as in the foregoing embodiments, and the description of the same or similar configurations follows the foregoing description.

[0125] Figure 7 This is a perspective view illustrating another embodiment of the display device utilizing a semiconductor light-emitting device according to the present invention. Figure 8 It is along Figure 7 A cross-sectional view cut by line DD. Figure 9 It is shown Figure 8 A conceptual diagram of a vertical semiconductor light-emitting device.

[0126] Referring to the above figures, the display device can be a display device using a vertical semiconductor light-emitting device in a passive matrix (PM) manner.

[0127] This display device includes a substrate 210, a first electrode 220, a conductive adhesive layer 230, a second electrode 240, and at least one semiconductor light-emitting device 250.

[0128] The substrate 210, which serves as a wiring substrate with the first electrode 220, may contain polyimide (PI) to achieve a flexible display device. Alternatively, any material with insulating and flexible properties can be used.

[0129] The first electrode 220 is located on the substrate 210 and can be formed as a bar-shaped electrode that extends in one direction. The first electrode 220 can be configured to function as a data electrode.

[0130] A conductive adhesive layer 230 is formed on the substrate 210 where the first electrode 220 is located. Similar to display devices using flip-chip type light-emitting devices, the conductive adhesive layer 230 can be anisotropic conductive film (ACF), anisotropic conductive paste, a solution containing conductive particles, etc. However, in this embodiment, the case where the conductive adhesive layer 230 is implemented using an anisotropic conductive film is also illustrated.

[0131] With the first electrode 220 located on the substrate 210, after the anisotropic conductive film is applied, if the semiconductor light-emitting device 250 is connected by applying heat and pressure, the semiconductor light-emitting device 250 is electrically connected to the first electrode 220. In this case, the semiconductor light-emitting device 250 is preferably configured to be located on the first electrode 220.

[0132] As described above, this type of electrical connection is generated because if heat and pressure are applied to the anisotropic conductive film, it will partially become conductive in the thickness direction. Therefore, the anisotropic conductive film is divided into conductive and non-conductive portions in the thickness direction.

[0133] In addition, since the anisotropic conductive film contains adhesive components, the conductive adhesive layer 230 not only realizes the electrical connection between the semiconductor light-emitting device 250 and the first electrode 220, but also realizes the mechanical bonding.

[0134] Thus, the semiconductor light-emitting device 250 is located on the conductive adhesive layer 230, thereby forming a single pixel in the display device. Because the semiconductor light-emitting device 250 has excellent brightness, even a small size can constitute a single unit pixel. For example, the size of such a single semiconductor light-emitting device 250 can be less than 80 μm in length on one side, and it can be a rectangular or square element. If it is rectangular, for example, it can be less than 20 × 80 μm.

[0135] This semiconductor light-emitting device 250 can be a vertical structure.

[0136] A plurality of second electrodes 240 are disposed between vertical semiconductor light-emitting devices. The second electrodes 240 are arranged in a direction that intersects the length direction of the first electrode 220 and are electrically connected to the vertical semiconductor light-emitting device 250.

[0137] Reference Figure 9 This vertical semiconductor light-emitting device includes: a p-type electrode 256, a p-type semiconductor layer 255 formed on the p-type electrode 256, an active layer 254 formed on the p-type semiconductor layer 255, an n-type semiconductor layer 253 formed on the active layer 254, and an n-type electrode 252 formed on the n-type semiconductor layer 253. In this case, the lower p-type electrode 256 can be electrically connected to the first electrode 220 through a conductive adhesive layer 230, and the upper n-type electrode 252 can be electrically connected to the second electrode 240 (described later). This vertical semiconductor light-emitting device 250 allows the electrodes to be positioned at the top and bottom, thus offering the significant advantage of reducing chip size.

[0138] Refer again Figure 8 A phosphor layer 280 may be formed on one side of the semiconductor light-emitting device 250. For example, if the semiconductor light-emitting device 250 is a blue semiconductor light-emitting device 251 that emits blue B light, a phosphor layer 280 for converting this blue B light into the hue of a unit pixel may be provided. In this case, the phosphor layer 280 may be a red phosphor 281 and a green phosphor 282 constituting a single pixel.

[0139] That is, at the location constituting a red unit pixel, a red phosphor 281 capable of converting blue light into red (R) light can be stacked on top of a blue semiconductor light-emitting device; at the location constituting a green unit pixel, a green phosphor 282 capable of converting blue light into green (G) light can be stacked on top of a blue semiconductor light-emitting device. Alternatively, a blue semiconductor light-emitting device can be used alone for the portion constituting a blue unit pixel. In this case, the red (R), green (G), and blue (B) unit pixels can form a single pixel.

[0140] However, the present invention is not limited thereto. As described in the display device using a flip-chip type light-emitting device, other structures for realizing blue, red, and green can be used.

[0141] Referring again to this embodiment, the second electrode 240 is located between the semiconductor light-emitting devices 250 and is electrically connected to the semiconductor light-emitting devices 250. For example, the semiconductor light-emitting devices 250 can be configured as a plurality of columns, and the second electrode 240 is located between the columns of the semiconductor light-emitting devices 250.

[0142] Since the distance between the semiconductor light-emitting devices 250 that constitute a single pixel is large enough, the second electrode 240 can be located between the semiconductor light-emitting devices 250.

[0143] The second electrode 240 can be formed as a long bar-shaped electrode that extends in one direction and can be arranged in a direction perpendicular to the first electrode.

[0144] Furthermore, the second electrode 240 and the semiconductor light-emitting device 250 can be electrically connected via a connection electrode protruding from the second electrode 240. More specifically, the connection electrode can be an n-type electrode of the semiconductor light-emitting device 250. For example, the n-type electrode is formed as an ohmic electrode for ohmic contact, and the second electrode 240 covers at least a portion of the ohmic electrode by printing or vapor deposition. Thus, the second electrode 240 and the n-type electrode of the semiconductor light-emitting device 250 can be electrically connected.

[0145] Refer again Figure 8 The second electrode 240 may be located on the conductive adhesive layer 230. Depending on the situation, a transparent insulating layer (not shown) containing silicon oxide (SiOx) or the like may be formed on the substrate 210 on which the semiconductor light-emitting device 250 is formed. If the second electrode 240 is to be provided after the transparent insulating layer is formed, the second electrode 240 will be located on the transparent insulating layer. Alternatively, the second electrode 240 may be formed separately from the conductive adhesive layer 230 or the transparent insulating layer.

[0146] If a transparent electrode such as indium tin oxide (ITO) is used to mount the second electrode 240 onto the semiconductor light-emitting device 250, there is a problem of poor adhesion between the ITO material and the n-type semiconductor layer. Therefore, in this invention, the second electrode 240 is mounted between the semiconductor light-emitting devices 250, thus eliminating the need for a transparent electrode such as ITO. Therefore, the choice of transparent material is not limited, and a conductive material with good adhesion to the n-type semiconductor layer can be used as a horizontal electrode, thereby improving light extraction efficiency.

[0147] Refer again Figure 8 The partition wall 290 can be located between the semiconductor light-emitting devices 250. That is, in order to separate the semiconductor light-emitting devices 250 that constitute a single pixel, a partition wall 290 can be arranged between the vertical semiconductor light-emitting devices 250. In this case, the partition wall 290 can serve to separate the individual unit pixels from each other and can be formed integrally with the conductive adhesive layer 230. For example, the partition wall can be formed by inserting the semiconductor light-emitting devices 250 into an anisotropic conductive film, and the substrate of the anisotropic conductive film can be formed.

[0148] In addition, if the substrate of the anisotropic conductive film is black, the partition wall 290 can increase the contrast while having reflective properties, even without an additional black insulator.

[0149] As another example, additional reflective partitions may be provided as partition 290. Depending on the purpose of the display device, partition 290 may include a black or white insulator.

[0150] If the second electrode 240 is located precisely on the conductive adhesive layer 230 between the semiconductor light-emitting devices 250, the partition wall 290 can be located between the vertical semiconductor light-emitting devices 250 and the second electrode 240. Therefore, individual unit pixels can be constructed with small sizes using the semiconductor light-emitting devices 250. Since the spacing between the semiconductor light-emitting devices 250 is relatively wide, the second electrode 240 can be located between the semiconductor light-emitting devices 250, achieving the effect of a flexible display device with HD image quality.

[0151] In addition, such as Figure 8 As shown, in order to improve contrast, a black matrix 291 can be arranged between each phosphor. That is, this black matrix 291 can improve the contrast between light and dark areas.

[0152] In the display device of the present invention described above that utilizes a semiconductor light-emitting device, the semiconductor light-emitting device is a flip-chip type, disposed on a wiring substrate and used as a single pixel.

[0153] Figures 10 to 14 This is a cross-sectional view illustrating a portion of the manufacturing process of a display device including a light-emitting device according to an embodiment of the present invention.

[0154] Reference Figure 10 In one embodiment of the present invention, the light-emitting device 330 can be provided in a state where it is formed on the growth substrate 600 and divided into individual unit light-emitting devices 330.

[0155] This single light-emitting device 330 may include a semiconductor layer comprising a first conductive semiconductor layer 331, a second conductive semiconductor layer 332, and an active layer 333 located between the first conductive semiconductor layer 331 and the second conductive semiconductor layer 332. The horizontal cross-sectional shape of this semiconductor layer may be any one of a circle, an ellipse, or a polygon.

[0156] As an example, the first conductivity type can be n-type. Therefore, the second conductivity type can be p-type. Hereinafter, embodiments of the present invention will be described focusing on an example where the first conductivity type is n-type and the second conductivity type is p-type. As an example, the first conductivity semiconductor layer 331 can be an n-type semiconductor layer, and the second conductivity semiconductor layer 332 can be a p-type semiconductor layer. However, embodiments of the present invention are not limited to this. That is, as another example, the first conductivity semiconductor layer 331 can be a p-type semiconductor layer, and the second conductivity semiconductor layer 332 can be an n-type semiconductor layer.

[0157] As an example, the light-emitting device 330 may include a passivation layer 334 for protecting the outer surface from electrical shocks. This passivation layer 334 may be partially removed during the assembly process or wiring connection process.

[0158] A sacrificial layer 420 may be formed on the top surface of the light-emitting device 330. As an example, this sacrificial layer 420 may include a metal thin film such as aluminum (Al). As an example, the sacrificial layer 420 may be formed as an aluminum thin film.

[0159] Reference Figure 10 The sacrificial layer 420 can be located on the top surface of the light-emitting device 330. As an example, the width or diameter of the sacrificial layer 420 can be equal to or smaller than the width or diameter of the top surface of the light-emitting device 330.

[0160] As an example, when the light-emitting device 330 is cylindrical, the diameter of the sacrificial layer 420 can be equal to or smaller than the diameter of the top surface of the light-emitting device 330.

[0161] This sacrificial layer 420 can contact the passivation layer 334 located on the top surface of the light-emitting device 330 and the second conductive semiconductor layer 332 exposed on the top surface of the light-emitting device 330. This sacrificial layer 420 can be formed in a stepped shape at the portion that contacts the second conductive semiconductor layer 332.

[0162] Reference Figure 11 An adhesive layer 410 may be formed on the sacrificial layer 420. This adhesive layer 410 may include an adhesive resin material. As an example, the adhesive layer 410 may include a photoresist material.

[0163] As an example, the width or diameter of the sacrificial layer 420 may be greater than the width or diameter of the adhesive layer 410. As an example, the adhesive layer 410 may contact and form with the stepped portion of the sacrificial layer 420.

[0164] Reference Figure 12 The adhesive layer 410 can be adhered to the transfer substrate 400.

[0165] As an exemplary embodiment, the transfer substrate 400 may be a sapphire substrate. A rough surface may be formed on the first surface 401 of such a transfer substrate 400. As an example, this rough surface may be formed by wet etching of the first surface 401 of the sapphire substrate. Through this etching, fine patterns in the shape of hexagonal cones to cones may be formed on the first surface 401 of the sapphire substrate.

[0166] As an exemplary embodiment, the rough surface may include an uneven pattern that increases the surface area of ​​the first surface 401 of the transfer substrate 400. This uneven pattern can enhance the adhesive force of the adhesive layer 410 by increasing the surface area of ​​the first surface 401 on the transfer substrate 400 to which the adhesive layer 410 is adhered.

[0167] Such fine patterns or raised patterns can be formed on the entire first surface 401. Therefore, the fine patterns or raised patterns and the first surface 401 can be described using the same reference numerals.

[0168] Figure 13 This illustrates a state where the light-emitting device 330 is adhered to a fine pattern or embossed pattern 401 formed on the first surface 401 of the transfer substrate 400 via an adhesive layer 410. As described above, the sacrificial layer 420 may be located between the adhesive layer 410 and the light-emitting device 330.

[0169] As described above, the width or diameter of the sacrificial layer 420 can be equal to or smaller than the width or diameter b of the top surface of the light-emitting device 330.

[0170] In addition, the width or diameter a of the adhesive layer 410 may be equal to or less than the width or diameter b of the top surface of the light-emitting device 330.

[0171] As described above, the adhesive layer 410 can be bonded to the adhesive portion 402, which forms a local area on the first surface 401 of the transfer substrate 400.

[0172] Since the light-emitting device 330 is adhered to the fine pattern or embossed pattern 401 formed on the first surface 401 of the transfer substrate 400 and its surface area increased by the adhesive layer 410, sufficient adhesion can be ensured even if the adhesive portion 402 of the adhesive layer 410 becomes smaller. Therefore, it is easier to ensure the alignment margin between the adhesive layer 410 and the light-emitting device 330. This will be explained later.

[0173] After that, as Figure 14 As shown, if the growth substrate 600 is removed from the light-emitting device 330, a transfer substrate assembly 10 is formed (see reference). Figure 18 On the other hand, depending on the situation, the growth substrate 600 was not removed. Figure 13 The state shown can also be referred to as a transfer substrate assembly.

[0174] Figure 15 This is a photograph showing a portion of a transfer substrate assembly according to an embodiment of the present invention. Figure 16 It is Figure 15 An enlarged photograph of part A.

[0175] Figure 15 This is a scanning electron microscope (SEM) image showing the state in which each light-emitting device 330 is stably adhered to the first surface 401 of the transfer substrate 400. (Refer to...) Figure 15 This illustrates a state where fine patterns or embossed patterns 401 in the shape of a cone or hexagonal cone are distributed on a transfer substrate 400 to form a rough surface, and individual light-emitting devices 330 are adhered to this rough surface.

[0176] Reference Figure 16 , Figure 16 The image is enlarged to show the state in which the light-emitting device 330 is bonded to the adhesive portion 402 by a fine pattern or embossed pattern 401, such that the direction of the first conductive semiconductor layer 331 is toward the fine pattern or embossed pattern 401.

[0177] Figure 17 This is a cross-sectional view showing the state of individual light-emitting devices dispersed during the manufacturing process of a display device including a light-emitting device according to an embodiment of the present invention.

[0178] As an exemplary embodiment, the light-emitting device 330 of one embodiment of the present invention may have electrodes formed on the surface where the growth substrate 600 is removed. Such electrodes may include a magnetic layer (not shown). Alternatively, the magnetic layer may be formed separately from the electrodes.

[0179] For use as a sub-pixel in a display device, the light-emitting device 330 can be magnetically assembled onto the wiring substrate 310 (see reference). Figure 23Alternatively, an additional assembly substrate (not shown) may be used. As an example, the light-emitting device 330 can be assembled in the fluid using magnetic force after being dispersed into the fluid. Therefore, the magnetic layer facilitates the process of assembling the light-emitting device 330 using magnetic force.

[0180] As an example, the sacrificial layer 420 can be removed after the transfer substrate assembly 10 is placed in a fluid, thereby dispersing the light-emitting device 330 into the fluid. As another example, the fluid may include a liquid capable of etching the metal used as the sacrificial layer 420, thereby removing the sacrificial layer 420. As described above, since the size of the sacrificial layer 420 is reduced, the time required to remove the sacrificial layer 420 is also reduced. Therefore, the process time can be shortened.

[0181] Figure 18 This is a diagram illustrating the alignment allowance of the transfer substrate assembly of the comparative example and the transfer substrate assembly of the embodiment of the present invention.

[0182] Reference Figure 18 As a comparative example, a transfer substrate assembly 1 that uses a conventional transfer substrate 40 without a rough surface to transfer the light-emitting device 330 will be compared and explained with the transfer substrate assembly 10 of the embodiment of the present invention.

[0183] From a manufacturing process perspective, the characteristics of the transfer substrate assembly can be considered using two benchmarks.

[0184] First, considering the production volume of light-emitting devices (chips), in order to improve the productivity of the dispersion process of light-emitting devices 330 bonded to the transfer substrate 400 (donor substrate), the area of ​​the sacrificial layer 420 and the area of ​​the adhesive portion 402 can be reduced, thereby reducing the time required to remove the sacrificial layer 420 and disperse the light-emitting device 330 into the fluid.

[0185] To reduce the dispersion time of the light-emitting device 330, it is necessary to reduce the thickness and size of the sacrificial layer 420 and the size of the adhesive layer 410. Compared with the comparative example, according to the embodiment of the present invention, the thickness of the sacrificial layer 420 can be reduced. The width (diameter) of the sacrificial layer 420 can be reduced. In addition, the width (diameter) of the adhesive layer 410 can be reduced.

[0186] On the other hand, based on the dispersion process, the adhesive layer 410 can be adhered to the transfer substrate 400 with a rough surface, thereby reducing the size of the adhesive layer 410 and thus further ensuring the alignment margin.

[0187] When the size of the light-emitting device 330 becomes very small, the size of the adhesive layer 410 needs to be reduced to ensure process margin. Typically, the adhesive force of the adhesive layer 410 might be reduced. However, according to an embodiment of the present invention, due to the uneven pattern 401 of the transfer substrate 400, the adhesive area increases, so the adhesive force of the adhesive layer 410 does not decrease, but rather increases.

[0188] In the comparative example of the transfer substrate assembly 1, if the thickness of the sacrificial layer 42 is thinner, the possibility of a short circuit (C) of the sacrificial layer 42 occurring in the edge region of the MESA structure (mesa structure) of the second conductive semiconductor layer 332 of the light-emitting device 330 will increase.

[0189] On the other hand, the adhesive layer 41 should be aligned and adhered to the transfer substrate 40 along the alignment line D. However, if the alignment of the adhesive layer 41 is moved to the portion marked E, the adhesive layer 41 may bond with the sacrificial layer 42 in the area where the sacrificial layer 42 is short-circuited (C). As a result, the possibility that the light-emitting device 330 is not dispersed as expected increases. As an example, in the structure of the comparative example, the contact area is reduced due to the alignment error.

[0190] As an example, in order to reduce dispersion time, if the thickness of the sacrificial layer 42 is reduced in the assembly structure such as the comparative example, the adhesive layer 41 may locally come into direct contact with the light-emitting device 330 chip due to the coverage problem of the deposition equipment at the edge of the MESA region, and the light-emitting device 330 will not be dispersed even if the sacrificial layer 42 is removed.

[0191] However, according to embodiments of the present invention, the problems described above can be solved.

[0192] As the size of the light-emitting device 330 becomes smaller, the size of the MESA (Mesh Adhesive Interface) also decreases, thus reducing the alignment allowance of the adhesive layer 410. However, according to embodiments of the present invention, the size of the adhesive layer 410 can be reduced, thereby ensuring sufficient alignment allowance.

[0193] As an example, even when the alignment lines are misaligned (D->E), the bonding area may remain unchanged. Therefore, the adhesive layer 410 can bond the light-emitting device 330 to the transfer substrate 400 with sufficient adhesive strength. Furthermore, due to this alignment error, no problems arise during dispersion. On the other hand, the area of ​​the sacrificial layer 420 can also be reduced.

[0194] According to embodiments of the present invention, the size of the pattern in the adhesive layer 410 can be reduced, thereby reducing the size and thickness of the sacrificial layer 420. Consequently, the time required to etch the sacrificial layer 420 is reduced, thereby reducing the dispersion time of the light-emitting device 330. This improves productivity.

[0195] Figure 19 This is a photograph showing the state of the light-emitting device of the comparative example bonded to the transfer substrate. Figure 20 This is a photograph showing the state in which the light-emitting device of an embodiment of the present invention is bonded to the transfer substrate.

[0196] In the comparative example process, chip loss occurs due to insufficient adhesion between the transfer substrate 40 and the light-emitting device 330 chip, as shown in the photograph.

[0197] That is, if a growth substrate on which the light-emitting device 330 is formed is bonded to a transfer substrate 40 with a flat surface, chip loss will occur due to insufficient bonding force.

[0198] Figure 19 The image shows a region where the light-emitting device chip is not bonded to the transfer substrate and has been removed. This leads to the loss of light-emitting devices and reduced yield.

[0199] On the other hand, according to embodiments of the present invention, such as Figure 20 As shown, if the light-emitting device 330 adheres to the transfer substrate 400 with sufficient adhesive force, chip loss will not occur.

[0200] As described above, typically, in order to disperse the light-emitting device 330 chip using microLEDs into individual chips in a fluid, the growth substrate 600 is bonded to the transfer substrate 400 (donor substrate) and then a dispersion process is performed.

[0201] At this point, during the bonding process between the growth substrate 600 and the transfer substrate 400, an appropriate level of adhesion is required to prevent chip loss after the dispersion and assembly processes.

[0202] According to an embodiment of the present invention, during the bonding process between the growth substrate 600 and the transfer substrate 400, chip loss can be reduced or prevented by increasing the adhesion force.

[0203] To increase the adhesion between the growth substrate 600 and the transfer substrate 400, the bonding strength of the photoresist material used in the adhesive layer 410 is crucial. Factors that increase the bonding strength of this photoresist material include improving the material properties of the photoresist and increasing the bonding area.

[0204] In terms of increasing the bonding area, if a typical transfer substrate with a flat surface is used, the adhesion between the growth substrate 600 and the transfer substrate 400 will be limited.

[0205] According to an embodiment of the present invention, by applying a concave-convex pattern 401 to the transfer substrate 400 to reduce the stress caused by pressure during the process, the light-emitting device chip can be stably bonded to the transfer substrate due to the increase in the bonding process area.

[0206] Figure 21 and Figure 22 This is a schematic diagram illustrating the manufacturing process of a display device according to an embodiment of the present invention.

[0207] Hereinafter, as an exemplary embodiment, the process of assembling the light-emitting device 330 onto the wiring substrate 310 after it is dispersed in a fluid will be briefly described.

[0208] Reference Figure 21 Light-emitting devices 330a, 330b, and 330c can be assembled on the assembly substrate 500.

[0209] In the assembly substrate 500, the assembly electrodes 530 (531, 532) can be disposed on the substrate 510 together with the insulating layer 520. As an example, a partition wall 540 can be disposed on the insulating layer 520, the partition wall 540 forming an assembly space for assembling the light-emitting devices 330a, 330b, 330c.

[0210] As described above, light-emitting devices 330a, 330b, and 330c can be assembled onto the assembly substrate 500 using magnet 700. In this case, as described above, light-emitting devices 330a, 330b, and 330c may include a magnetic layer. This assembly process of light-emitting devices 330a, 330b, and 330c can be performed in a fluid environment.

[0211] As described above, it is advantageous for the lower contact area to be larger than the upper contact area in order to impart up / down selectivity to the light-emitting devices 330a, 330b, and 330c. For this purpose, as an example, the contact area can be adjusted by patterning and / or etching the passivation layer of the light-emitting devices 330a, 330b, and 330c. Alternatively, as another example, the upper second conductive semiconductor layer 332 can be partially etched, thereby creating a difference in the upper / lower contact area.

[0212] Here, the light-emitting devices 330a, 330b, and 330c may include a red light-emitting device 330a, a green light-emitting device 330b, and a blue light-emitting device 330c. Figure 21 The following figures show three light-emitting devices, but more light-emitting devices 330a, 330b, and 330c can be assembled using magnet 500.

[0213] The light-emitting devices 330a, 330b, and 330c assembled on the assembly substrate 500 using magnets 700 can be fixed by dielectrophoresis (DEP) force when an electric field is applied to the assembly electrode 530.

[0214] Reference Figure 22The light-emitting devices 330a, 330b, and 330c assembled on the assembly substrate 500 can be transferred to the wiring substrate 310.

[0215] As an exemplary embodiment, the light-emitting devices 330a, 330b, and 330c assembled on the assembly substrate 500 can be transferred to a temporary substrate and then transferred to the wiring substrate 310.

[0216] The wiring substrate 310 may include a first electrode 312 arranged on the substrate 311. The first electrode 312 may be covered by an insulating layer 301.

[0217] The mounting layer 320 may be located on the insulating layer 301. This mounting layer 320 may have adhesive force, which fixes the light-emitting device 330 in the assembly process of the light-emitting device 330, and then cures and supports the light-emitting devices 330a, 330b, and 330c.

[0218] Figure 23 This is a cross-sectional view of a display device according to an embodiment of the present invention.

[0219] Reference Figure 23 According to one embodiment of the present invention, the display device may be configured such that a light-emitting device 330 forming a unit sub-pixel is disposed on a wiring substrate 310 on which first electrodes 312 are arranged. The wiring substrate 310 may include the first electrodes 312 arranged on a substrate 311.

[0220] A plurality of first electrodes 312 may be disposed on the substrate 311 of the wiring substrate 310. These first electrodes 312 can be used as wiring electrodes. The first electrodes 312 can be separated and located on the substrate 311. Here, the wiring electrodes can be used as data electrodes (pixel electrodes) or scan electrodes (common electrodes).

[0221] Although Figure 23 The diagram shows a single light-emitting device 330, but a single light-emitting device 330 forming three unit sub-pixels can constitute a single pixel. In this case, the light-emitting device 330 may include a red light-emitting device that emits red light, a green light-emitting device that emits green light, and a blue light-emitting device that emits blue light. Such unit pixels can be repeatedly disposed on the wiring substrate 310.

[0222] Although not illustrated, the first electrode 312 arranged on the wiring substrate 310 can be connected to a TFT layer on which a thin-film transistor (TFT) is disposed. Data electrodes (pixel electrodes) can be connected to this TFT layer. Detailed description of this is omitted.

[0223] A partition wall 320 for forming an assembly hole for the light-emitting device can be provided between the wiring substrate 310 and the light-emitting device 330.

[0224] As an exemplary embodiment, at least one of the top and bottom surfaces of the light-emitting device 330 may be circular. As an example, the light-emitting device 330 may be cylindrical or frustum conical.

[0225] When assembling the light-emitting device 330, in order to provide selectivity between the upper and lower parts, the lower area of ​​the light-emitting device 330 can be larger than the upper area.

[0226] Additionally, the display device 300 may include a first connecting electrode 340 that electrically connects the first electrode 312 and one side of the light-emitting device 330. This first connecting electrode 340 may be made of a metal with high electrical conductivity, such as Al (aluminum), Mo (molybdenum), Cu (silver), Ag (silver), or Pt (platinum).

[0227] As an exemplary embodiment, one side of the light-emitting device 330 connected to the first connection electrode 340 may be the side surface of the light-emitting layer 333 of the light-emitting device 330. As an example, the first connection electrode 340 may be connected in the lateral direction to the surface formed by the light-emitting layer 333 of the light-emitting device 330. This first connection electrode 340 may extend along the side surface of the first conductive semiconductor layer 331 of the light-emitting device 330 and form a side surface portion 342, thereby being electrically connected to the first conductive semiconductor layer 331.

[0228] As described above, the first connecting electrode 340 may include a side portion 342 located on the side of the light-emitting device 330 and a bottom portion 343 located on the top surface of the mounting layer 320.

[0229] Reference Figure 23 The first connecting electrode 340 can be disposed on both sides of the light-emitting device 330. Depending on the situation, the first connecting electrode 340 can also be disposed to cover the side of the light-emitting device 330.

[0230] A passivation layer 334 may be provided on the outer side of the portion of the light-emitting device 330 connected to the first connecting electrode 340. As described above, a passivation layer 334 may be provided on the outer side of the light-emitting device 330, and the first connecting electrode 340 may be located below the passivation layer 334. This passivation layer 334 can protect the outer surface of the light-emitting device 330.

[0231] A planarization layer 350 may be provided on the side of the first connecting electrode 340 and the light-emitting device 330. The planarization layer 350 may cover the first connecting electrode 340 and the light-emitting device 330. The planarization layer 350 may have a height equivalent to the upper side of the light-emitting device 330, or it may be configured to have a higher height.

[0232] At this time, the second conductive semiconductor layer 332 on the upper side of the light-emitting device 330 can be exposed. As an example, even when the planarization layer 350 has a height higher than the upper side of the light-emitting device 330, the second conductive semiconductor layer 332 of the light-emitting device 330 can still be exposed.

[0233] Alternatively, a second connection electrode 361 may be provided on the planarization layer 350 and electrically connected to the other side of the light-emitting device 330. As an example, this second connection electrode 361 may include a transparent electrode such as ITO. Therefore, light emitted from the light-emitting device 330 can pass through the second connection electrode 361 and be projected to the outside.

[0234] As described above, the first electrode 312 and the second electrode 360 ​​can be used as wiring electrodes. As an example, the first electrode 312 can be used as a data electrode (pixel electrode), and the second electrode 360 ​​can be used as a scan electrode (common electrode).

[0235] Reference Figure 23 The second connecting electrode 361 may be partially located on the light-emitting device 330. Depending on the situation, these second connecting electrodes 361 can be connected to each other via the second electrode 360.

[0236] The above description is merely an example of the technical concept of the present invention. Those skilled in the art can make various modifications and variations without departing from the essential characteristics of the present invention.

[0237] Therefore, the embodiments disclosed in this invention are not intended to limit the technical concept of the invention, but are used to illustrate the technical concept, and the scope of the technical concept of the invention is not limited by these embodiments.

[0238] The scope of protection of this invention should be interpreted by the appended claims, and all technical ideas within the equivalent scope should be interpreted as being included within the scope of this invention.

[0239] Industrial applicability

[0240] According to the present invention, a semiconductor light-emitting device such as a microLED, a transfer substrate assembly using the semiconductor light-emitting device, and a display device can be provided.

Claims

1. A transfer substrate assembly for transferring light-emitting devices, characterized in that, include: A transfer substrate, including a first surface having a roughened surface; An adhesive layer, partially located on a first surface of the transfer substrate; and The light-emitting device is adhered by the adhesive layer.

2. The transfer substrate assembly according to claim 1, characterized in that, It also includes a sacrificial layer located between the adhesive layer and the light-emitting device.

3. The transfer substrate assembly according to claim 2, characterized in that, The width or diameter of the sacrificial layer is greater than the width or diameter of the adhesive layer.

4. The transfer substrate assembly according to claim 2, characterized in that, The width or diameter of the sacrificial layer is equal to or smaller than the width or diameter of the contact surface of the light-emitting device.

5. The transfer substrate assembly according to claim 1, characterized in that, The transfer substrate is a sapphire substrate.

6. The transfer substrate assembly according to claim 5, characterized in that, The rough surface is formed by wet etching the first surface of the sapphire substrate.

7. The transfer substrate assembly according to claim 1, characterized in that, The rough surface includes a raised or recessed pattern that increases the surface area of ​​the first surface of the transfer substrate.

8. A method for manufacturing a display device, the display device comprising a light-emitting device, characterized in that, The method for manufacturing the display device includes: The step of forming a sacrificial layer on a single light-emitting device that is separately disposed on a growth substrate; The step of forming an adhesive layer on the sacrificial layer; The step of adhering the adhesive layer to the first surface of the transfer substrate having a roughened surface; and The step of removing the growth substrate.

9. The method for manufacturing a display device according to claim 8, characterized in that, It also includes the steps of removing the sacrificial layer and separating the individual light-emitting device from the first side of the transfer substrate.

10. The method for manufacturing a display device according to claim 9, characterized in that, The process of removing the sacrificial layer includes the steps of etching the sacrificial layer in a fluid and dispersing the individual light-emitting device into the fluid.

11. The method for manufacturing a display device according to claim 8, characterized in that, The width or diameter of the sacrificial layer is greater than the width or diameter of the adhesive layer.

12. The method for manufacturing a display device according to claim 8, characterized in that, The width or diameter of the sacrificial layer is equal to or smaller than the width or diameter of the contact surface of the light-emitting device.

13. The method for manufacturing a display device according to claim 8, characterized in that, The transfer substrate is a sapphire substrate.

14. The method for manufacturing a display device according to claim 13, characterized in that, The rough surface is formed by wet etching the first surface of the sapphire substrate.

15. The method for manufacturing a display device according to claim 8, characterized in that, The rough surface includes a raised or recessed pattern that increases the surface area of ​​the first surface of the transfer substrate.

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