Display module and manufacturing method thereof

Abstract

A display module and a display module manufacturing method are disclosed. Specifically, the display module according to the present disclosure includes: a circuit driving substrate; a plurality of first electrodes on the driving substrate; a plurality of semiconductor layers; the plurality of second electrodes respectively correspond to the plurality of first electrodes; a plurality of light emitting diodes (LEDs) including a plurality of protruding portions on the plurality of second electrodes and a plurality of metal layers connected to the plurality of second electrodes, respectively, the plurality of LEDs being disposed on the plurality of protruding portions; and the non-conductive film layer is arranged between the driving substrate and the plurality of LEDs, and the plurality of first electrodes and the plurality of second electrodes can be connected through the plurality of metal layers.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a display module and a method of manufacturing the same, and more particularly, to a display module in which a light emitting diode (LED) can be stably connected to a driving substrate and a method of manufacturing the same. Background Art

[0002] Recently, technology for minimizing the size of LEDs used in displays has made significant progress. In particular, recently, there has been an increasing demand for technology that can more efficiently connect the electrodes of an LED chip and the electrodes on a driving substrate while improving the performance of the display module.

[0003] In related art, there is the following technology: An anisotropic conductive film (ACF) is laminated on a driving substrate, an LED chip is transferred, and then heat and pressure are applied to the entire driving substrate to cure the ACF, and conductive balls in the ACF are used to electrically connect the electrodes of the LED chip and the electrodes on the driving substrate.

[0004] However, in related art, since the ACF is laminated on the entire substrate, in addition to the area where the LED chip contacts the driving substrate, the conductive balls are also completely scattered in unnecessary areas, resulting in a problem of increased manufacturing cost. This is because the conductive balls, which account for the largest percentage of the ACF material, are required more than necessary. In addition, in order for an LED chip with a very small size (e.g., a micro LED chip) to stably contact the driving substrate, the conductive balls inside the ACF should be uniformly aligned, so the manufacturing cost of the ACF further increases.

[0005] In addition, according to related art, as the LED chip becomes ultra-fine and has an ultra-fine pitch, the electrodes of the LED chip become very narrow. In this case, when the conductive balls aggregate or connect between the electrodes, this may cause the LED chip to not emit light due to a short circuit defect.

[0006] In addition, according to related art, in order for an LED chip with a very small size to stably contact the driving substrate, the conductive balls inside the ACF need to be uniformly aligned and the density of the conductive balls should be increased, but in this case, the penetration of the lower electrode pattern is interfered by the high density of the conductive balls, and there is a problem of increased difficulty in visual alignment during the transfer of the LED chip. Summary of the Invention

[0007] Solution to the Problem

[0008] Embodiments of the present disclosure solve the above problems and provide a display module in which an LED can be stably connected to a driving substrate and a method of manufacturing the same.

[0009] According to an embodiment of the present disclosure, a display module is provided, which includes: a driving substrate; a plurality of first electrodes on the driving substrate; a plurality of light-emitting diodes (LEDs), including a plurality of semiconductor layers, a plurality of second electrodes respectively corresponding to the plurality of first electrodes, a plurality of protrusions on each of the plurality of second electrodes, and a plurality of metal layers on the plurality of protrusions, each metal layer among the plurality of metal layers being connected to one of the plurality of second electrodes; and a non-conductive film layer between the driving substrate and the plurality of LEDs, wherein the plurality of first electrodes and the plurality of second electrodes are connected through the plurality of metal layers.

[0010] According to one or more embodiments of the present disclosure, the plurality of first electrodes and the plurality of second electrodes are connected by bringing the plurality of first electrodes into contact with the plurality of metal layers through thermocompression bonding of the non-conductive film layer.

[0011] According to one or more embodiments of the present disclosure, the non-conductive film layer is black.

[0012] According to one or more embodiments of the present disclosure, the plurality of protrusions include a polymer having elastic restoring force.

[0013] According to one or more embodiments of the present disclosure, the plurality of protrusions include one of the following shapes: a hemispherical shape, a conical shape, a pyramidal shape, a triangular prism shape in which one cross-section contacts one of the plurality of second electrodes, and a semi-cylindrical shape including a rectangular surface that contacts one of the plurality of second electrodes.

[0014] According to one or more embodiments of the present disclosure, the plurality of LEDs further include a capping layer formed on the plurality of metal layers to prevent oxidation of the plurality of metal layers.

[0015] According to one or more embodiments of the present disclosure, the capping layer includes at least one of indium tin oxide (ITO), indium zinc oxide (IZO), and gold (Au).

[0016] According to one or more embodiments of the present disclosure, the plurality of LEDs are flip-chip type LEDs, and each flip-chip type LED has a horizontal length and a vertical length of not less than 1 μm and not more than 100 μm.

[0017] According to an embodiment of the present disclosure, a method of manufacturing a display module is provided, which includes: forming a plurality of first electrodes on a driving substrate including a circuit; manufacturing a plurality of light-emitting diodes (LEDs), the plurality of LEDs including a plurality of semiconductor layers, a plurality of second electrodes respectively corresponding to the plurality of first electrodes, a plurality of protrusions on each of the plurality of second electrodes, and a plurality of metal layers on the plurality of protrusions, and each metal layer of the plurality of metal layers being connected to one of the plurality of second electrodes; forming a non-conductive film layer on the driving substrate; transferring the plurality of LEDs onto the non-conductive film layer; and performing thermocompression bonding on the non-conductive film layer such that the plurality of first electrodes and the plurality of second electrodes are connected by contacting each other through the plurality of first electrodes and the plurality of metal layers.

[0018] According to one or more embodiments of the present disclosure, manufacturing the plurality of LEDs includes: forming a plurality of semiconductor layers on a growth substrate; forming a plurality of second electrodes on the plurality of semiconductor layers; forming an insulating organic film layer on the plurality of second electrodes; forming a plurality of protrusions by patterning the insulating organic film layer; and forming a plurality of metal layers on the plurality of protrusions.

[0019] According to one or more embodiments of the present disclosure, the non-conductive film layer is black.

[0020] According to one or more embodiments of the present disclosure, the plurality of protrusions include a polymer having elastic restoring force.

[0021] According to one or more embodiments of the present disclosure, the plurality of protrusions include one of the following shapes: a hemispherical shape, a conical shape, a pyramidal shape, a triangular prism shape in which one cross-section contacts one of the plurality of second electrodes, and a semi-cylindrical shape in which a rectangular cross-section contacts one of the plurality of second electrodes.

[0022] According to one or more embodiments of the present disclosure, manufacturing the plurality of LEDs includes: forming a capping layer on the plurality of metal layers to prevent oxidation of the plurality of metal layers.

[0023] According to one or more embodiments of the present disclosure, the capping layer includes at least one of indium tin oxide (ITO), indium zinc oxide (IZO), and gold (Au). BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a diagram showing the structure of a display module according to an embodiment of the present disclosure.

[0025] Figure 2 is an enlarged view of a part of the display module according to an embodiment of the present disclosure.

[0026] Figure 3 and Figure 4 show details of the protrusions and the metal layers according to various embodiments of the present disclosure.

[0027] Figure 5 and Figure 6 is a diagram showing an LED and a metal layer formed on a protrusion according to various embodiments of the present disclosure.

[0028] Figure 7 is a flowchart showing a method for manufacturing a display module according to an embodiment of the present disclosure.

[0029] Figures 8 to 11 is a diagram showing steps of a method for manufacturing a display module according to an embodiment of the present disclosure.

[0030] Figure 12 is a flowchart showing a method for manufacturing an LED according to an embodiment of the present disclosure.

[0031] Figures 13 to 15 is a diagram showing steps of a method for manufacturing an LED according to an embodiment of the present disclosure. Detailed Description

[0032] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it is to be understood that the present disclosure is not limited to the exemplary embodiments described below, and also includes various modifications, equivalents, and / or alternatives of these exemplary embodiments. Regarding the description of the drawings, like reference numerals may be used for like components.

[0033] In the following description, when it is determined that a detailed description of the related art may obscure the gist of the present disclosure, such a detailed description may be omitted.

[0034] In addition, the following embodiments may be combined and modified in various different forms, and the scope of the technical spirit of the present disclosure is not limited to the following examples. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the technical spirit to those skilled in the art.

[0035] The terms used herein are for describing certain embodiments and are not intended to limit the scope of the claims. Unless otherwise specified, singular expressions include plural expressions.

[0036] In this specification, expressions such as "having", "may have", "including", "may include", etc. indicate the presence of corresponding features (e.g., components such as numbers, functions, operations, or parts), and do not exclude the presence of additional features.

[0037] In this document, expressions such as "at least one of A and / or B" or "one or more of A and / or B" include all possible combinations of the listed items. For example, "at least one of A and B" or "at least one of A or B" includes any of the following: (1) at least one A, (2) at least one B, or (3) at least one A and at least one B.

[0038] As used herein, the terms "first", "second", etc. may represent various components regardless of their order and / or importance, and may be used to distinguish one component from another without otherwise limiting the components.

[0039] If it is described that a certain element (e.g., the first element) is "operatively or communicatively coupled to" / "operatively or communicatively coupled with" another element (e.g., the second element), or "connected to" / "connected with" another element (e.g., the second element), it should be understood that the certain element may be directly connected to the other element or through other elements (e.g., the third element).

[0040] On the other hand, if it is described that a certain element (e.g., the first element) is "directly coupled to" or "directly connected to" another element (e.g., the second element), it can be understood that there is no element (e.g., the third element) between the certain element and the other element.

[0041] In addition, the expression "configured to" used in the present disclosure may be interchangeably used with other expressions such as "suitable for", "capable of", "designed to", "adapted to", "made to", and "able to" according to the circumstances. At the same time, the term "configured to" does not necessarily mean that the device is "specially designed" in terms of hardware.

[0042] On the contrary, in some cases, the expression "a device configured to..." may mean that the device "is capable of" performing operations together with another device or component. For example, the phrase "a processor configured to perform A, B, and C" may represent a dedicated processor (e.g., an embedded processor) for performing the corresponding operations, or a general-purpose processor (e.g., a central processing unit (CPU) or an application processor) that can perform the corresponding operations by executing one or more software programs stored in a storage device.

[0043] According to an embodiment of the present disclosure, a module or unit performs at least one function or operation, and may be implemented in hardware, or software, or a combination of hardware and software. Additionally, except for "modules" or "units" that need to be implemented in specific hardware, multiple "modules" or multiple "units" may be integrated into at least one module and may be implemented as at least one processor.

[0044] It should be understood that the various elements and regions in the drawings may not be shown to scale. Accordingly, the scope of the present disclosure is not limited by the relative sizes or spacings in the drawings.

[0045] Hereinafter, embodiments will be described in detail with reference to the drawings so that those skilled in the art to which the present disclosure pertains can easily fabricate and use the embodiments.

[0046] Figure 1 is a diagram showing the structure of a display module 100 according to an embodiment of the present disclosure. Figure 2 is an enlarged view of region 1 of the display module 100 according to an embodiment of the present disclosure.

[0047] The display module 100 according to an embodiment of the present disclosure refers to a device capable of displaying an image. In particular, the display module 100 may be included in an electronic device and display an image. When the display module 100 is included in an electronic device, the display module 100 may display an image under the control of a processor included in the electronic device.

[0048] The display module 100 according to an embodiment of the present disclosure may represent the entire display panel included in an electronic device, or a plurality of display modules 100 may be combined to form one display panel. There is no specific limitation on the type of electronic device to which the display module 100 to which the present disclosure is applied.

[0049] Referring to Figure 1 , the display module 100 may include a driving substrate 110, a plurality of first electrodes 120, a plurality of LEDs 130, and a non-conductive film layer 140.

[0050] The driving substrate 110 refers to a substrate including a driving circuit for driving a plurality of LEDs 130. The driving substrate 110 may also be referred to as a circuit board. Specifically, a plurality of LEDs 130 may be disposed on the driving substrate 110 including the driving circuit to be electrically connected to the driving circuit. The display module 100 may be driven in an active matrix type or a passive matrix type, and the driving circuit may be designed according to the driving method. The driving substrate 110 may be implemented in various types such as glass, flexible printed circuit board (PCB), ceramic, and the like.

[0051] The driving circuit may be connected to the plurality of first electrodes 120 and may include a plurality of circuit elements such as switching elements. The switching element is a semiconductor element capable of controlling the driving of a plurality of LED 130 elements included in the display module 100 and serves as a kind of switch for each pixel of the display device. For example, a thin film transistor (TFT) may be used as the switching element.

[0052] A plurality of first electrodes 120 may be formed on the driving substrate 110 to be connected to a driving circuit included in the driving substrate 110 and may be connected to a plurality of second electrodes 132 (described below) included in the plurality of LEDs 130. That is, the plurality of first electrodes 120 may be used to electrically connect the driving circuit and the plurality of LEDs 130. In the present disclosure, the term “first electrode” is used to distinguish the first electrode 120 from the second electrode 132 (described below) included in the LED 130, and may be replaced with terms such as “first electrode pad”.

[0053] The plurality of LEDs 130 may emit light under the control of the driving substrate 110. In the present disclosure, the term “LED” may represent a plurality of LED chips in a state where a chip-level packaging process for the plurality of LEDs 130 has been completed.

[0054] Specifically, as Figure 1 shown, the plurality of LEDs 130 may be implemented in a flip-chip type, in which the plurality of second electrodes 132 are disposed toward the opposite surface of the light-emitting surface of the LED 130. Additionally, the plurality of LEDs 130 may be implemented with micro-LEDs having both a horizontal length and a vertical length of 1 - 100 μm. However, the type of the plurality of LEDs 130 according to embodiments of the present disclosure is not limited to a specific type.

[0055] Referring to Figure 2 which is an enlarged view of region 1 of Figure 1 , each of the plurality of LEDs 130 according to embodiments of the present disclosure may include a plurality of semiconductor layers 131, a plurality of second electrodes 132, a plurality of protrusions 133, and a plurality of metal layers 134.

[0056] Although not specifically shown, the plurality of semiconductor layers 131 may include an n-type semiconductor layer, a p-type semiconductor layer, and a light-emitting layer.

[0057] The n-type semiconductor layer and the p-type semiconductor layer may be formed of compound semiconductors such as III-V group, II-VI group, etc. The n-type semiconductor layer and the p-type semiconductor layer may be formed of nitride semiconductor layers. For example, the n-type semiconductor layer may be an n-gallium nitride (GaN) semiconductor layer, and the p-type semiconductor layer may be a p-GaN semiconductor layer, but it should be understood that one or more other embodiments are not limited thereto. That is, the n-type semiconductor layer and the p-type semiconductor layer may be made of various materials according to various characteristics required, designed, or used for the LED 130.

[0058] An n-type semiconductor is a semiconductor that uses free electrons as carriers to enable charge migration and can be formed by doping with an n-type dopant (e.g., Si, Ge, Sn, Te, etc.). A p-type semiconductor is a semiconductor that uses holes as carriers to enable charge migration and can be formed by doping with a p-type dopant (e.g., Mg, Zn, Ca, Ba, etc.).

[0059] The light-emitting layer, n-type semiconductor layer, and p-type semiconductor layer can be formed of various semiconductors having a bandgap corresponding to a specific region within the spectrum. For example, a red LED 130 having a light wavelength of 600 - 750 nm can include one or more layers based on an AlInGaP-based semiconductor. At least a portion of the plurality of LEDs 130 can be implemented by a blue LED 130 having a light wavelength of 450 - 490 nm and a green LED having a light wavelength of 500 - 570 nm, and these LEDs can each include one or more layers based on an AlInGaN-based semiconductor.

[0060] Figure 1 The three LEDs 130 shown are a red LED 130-1, a green LED 130-2, and a blue LED 130-3, respectively. The red LED 130-1, green LED 130-2, and blue LED 130-3 can implement one pixel of the display module 100, but according to embodiments of the present disclosure, the number and arrangement method of the LEDs 130 for each pixel are not limited to a specific configuration.

[0061] The light-emitting layer is located between the n-type semiconductor layer and the p-type semiconductor layer and is the layer where electrons (carriers of the n-type semiconductor layer) and holes (carriers of the p-type semiconductor layer) meet. When electrons and holes meet in the light-emitting layer, a potential barrier is formed by the recombination of the electrons and holes. When the electrons and holes transition to a lower energy level outside the potential barrier according to the applied voltage, light of a corresponding wavelength is emitted.

[0062] Here, the light-emitting layer can have a multi-quantum well (MQW) structure, but embodiments of the present disclosure are not limited thereto, and the light-emitting layer can have various structures such as a single quantum well (SQW) structure or a quantum dot (QD) structure. When the light-emitting layer is formed as an MQW structure, the well layer / barrier layer of the light-emitting layer can be formed, for example but not limited to, a structure of InGaN / GaN, InGaN / InGaN, GaAs(InGaGs) / AlGaAs. The number of quantum wells included in the light-emitting layer is not limited to a specific number.

[0063] A plurality of second electrodes 132 may be formed on the plurality of semiconductor layers 131 to be connected to the plurality of semiconductor layers 131 and may also be connected to the plurality of first electrodes 120 formed on the driving substrate 110. That is, the plurality of second electrodes 132 may be connected to the corresponding plurality of first electrodes 120 to electrically connect the driving circuit to the plurality of LEDs 130. In the present disclosure, the term "second electrode" is a term used to distinguish from the first electrode 120 formed on the driving substrate 110 and may be replaced with a term such as "second electrode pad".

[0064] The plurality of second electrodes 132 may include an n-type electrode connected to the n-type semiconductor layer and a p-type electrode connected to the p-type semiconductor layer. The n-type electrode and the p-type electrode may also be connected to one of the first electrodes 120. The number of the second electrodes 132 connected to one of the LEDs 130 and the number of the corresponding first electrodes 120 are not limited to a specific configuration.

[0065] The plurality of protrusions 133 may refer to protrusion features formed on each of the plurality of second electrodes 132. The plurality of protrusions 133 may include a polymer having an elastic restoring force. For example, the plurality of protrusions 133 may be made of a material such as polyimide (PI) or epoxy resin, and as long as it is an insulating organic material having an elastic restoring force, it may be the material of the plurality of protrusions 133 according to an embodiment of the present disclosure. The plurality of protrusions 133 may be formed by forming an insulating organic film layer on the plurality of second electrodes 132 and patterning the formed insulating organic film layer.

[0066] The plurality of protrusions 133 may be one of a hemispherical shape, a conical shape, or a pyramid shape. Additionally, the plurality of protrusions may be a triangular prism shape in which one surface contacts one of the second electrodes 132, and a semi-cylindrical shape in which a rectangular surface contacts one of the second electrodes 132. The shape of the plurality of protrusions 133 will be described in detail with reference to Figures 3 to 6 The shape of the plurality of protrusions 133 will be described in detail.

[0067] The plurality of metal layers 134 may be formed on the plurality of protrusions 133 and connected to the plurality of second electrodes 132. Specifically, each of the plurality of metal layers 134 may be formed on the plurality of protrusions 133 and may be connected to one of the second electrodes 132. Additionally, the plurality of metal layers 134 may be connected to one of the first electrodes 120 through a thermocompression bonding process as described below. That is, the plurality of metal layers 134 may be used to electrically connect the plurality of first electrodes 120 and the plurality of second electrodes 132. For example, the plurality of metal layers 134 may be formed of metals such as Ti, Al, Cu, Ni, Au, etc.

[0068] Although Figure 1 and Figure 2Although not shown in the figure, the plurality of LEDs 130 may further include a capping layer formed on the plurality of metal layers 134 to prevent oxidation of the plurality of metal layers 134. For example, the capping layer may be made of indium tin oxide (ITO), indium zinc oxide (IZO), or gold (Au).

[0069] Although Figure 1 and Figure 2 Although not shown in the figure, the plurality of LEDs 130 may further include a reflective layer formed to reflect light emitted from the light-emitting layer in the direction of the light-emitting surface of the LED 130 to improve the light-emitting efficiency of the LED 130. In addition, the plurality of LEDs 130 may further include an insulating layer for stabilizing the device characteristics of the plurality of LEDs 130. In addition, various configurations for improving characteristics such as the light-emitting efficiency of the plurality of LEDs 130 may be included in the plurality of LEDs 130.

[0070] The non-conductive film (NCF) layer 140 may combine the driving substrate 110 and the plurality of LEDs 130. The non-conductive film layer 140 may be formed between the driving substrate 110 and the plurality of LEDs 130. The non-conductive film layer 140 may be in contact with the plurality of first electrodes 120 and the plurality of metal layers 134 while being cured by thermocompression bonding, thereby electrically connecting the plurality of first electrodes 120 and the plurality of second electrodes 132. That is, the plurality of first electrodes 120 and the plurality of second electrodes 132 may be connected through the plurality of metal layers 134. More specifically, as the plurality of first electrodes 120 and the plurality of metal layers 134 are brought into contact by thermocompression bonding of the non-conductive film layer 140, the plurality of first electrodes 120 and the plurality of metal layers 134 may be connected.

[0071] In addition, the non-conductive film layer 140 may mechanically stabilize the plurality of LEDs 130 by filling the gap existing between the driving substrate 110 and the plurality of LEDs 130, and may serve to offset the mismatch in the coefficient of thermal expansion (CTE) between the driving substrate 110 and the plurality of LEDs 130 (i.e., underfill). The material of the non-conductive film may be any thermosetting material capable of performing such underfill.

[0072] The non-conductive film layer 140 according to an embodiment of the present disclosure may be black. The non-conductive film layer 140 may be implemented as a transparent color, but when implemented as black, there is no need to form a black matrix (BM) on the upper portion of the plurality of LEDs 130, and thus, the manufacturing process efficiency of the display module 100 may be improved.

[0073] It has been described that a plurality of protrusions 133 are formed on a plurality of second electrodes 132 included in a plurality of LEDs 130, a plurality of metal layers 134 are formed on the plurality of protrusions 133, and the plurality of first electrodes 120 and the plurality of second electrodes 132 are connected through the plurality of metal layers 134. However, at least a part of the second electrodes 132 and the plurality of metal layers 134 may be integrated into one configuration.

[0074] For example, one of the second electrodes 132 that does not contact the semiconductor layer through a contact hole (via) among the plurality of second electrodes 132 may be implemented as an element integrated with one of the metal layers 134. For example, when the plurality of semiconductor layers 131 include an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer sequentially stacked on a growth substrate, at least one protrusion 133 and at least one metal layer 134 are formed instead of a p-type electrode connected to the p-type semiconductor layer, so that at least one metal layer 134 may serve the role of at least one second electrode 132. When at least some of the plurality of second electrodes 132 are integrated with the plurality of metal layers 134 as described above, the manufacturing process efficiency of the display module 100 can be improved.

[0075] The display module 100 according to an embodiment of the present disclosure may be included in an electronic device to display an image under the control of a processor included in the electronic device. In particular, the electronic device may include the display module 100, a memory for storing image data, and a processor for controlling the display module 100 to display an image based on the image data. Here, as described above, the display module 100 may include a driving substrate 110 (e.g., a circuit driving substrate) and a plurality of first electrodes 120 formed on the driving substrate 110. The display module 100 may include a plurality of semiconductor layers 131, a plurality of second electrodes 132 corresponding to each of the plurality of first electrodes 120, a plurality of protrusions 133 formed on each of the plurality of second electrodes 132, and a plurality of light-emitting diodes 130 formed on the plurality of protrusions 133 and each including a plurality of metal layers 134 connected to the plurality of second electrodes 132. In addition, the display module 100 may include a non-conductive film layer 140 formed between the driving substrate 110 and the plurality of LEDs 130, and the plurality of first electrodes 120 and the plurality of second electrodes 132 may be connected through the plurality of metal layers 134.

[0076] According to the above various embodiments, in the display module 100, the first electrodes 120 included in the plurality of LEDs 130 are connected to the second electrodes 132 formed on the driving substrate 110 through the protrusions 133 and the metal layers 134 (the metal layers 134 of the protrusion type may be referred to as metal protrusions) included in the plurality of LEDs 130, so that the plurality of LEDs 130 are stably connected to the driving substrate 110, thereby significantly improving the performance stability of the display module 100 and the manufacturing process efficiency of the display module 100.

[0077] In particular, compared with the case of connecting the LED and the driving substrate by using conductive balls as in the comparative example or the case of forming metal protrusions on the electrodes of the driving substrate, when metal protrusions are formed on the electrodes of the LED 130, the manufacturing process efficiency can be significantly improved, and the manufacturing cost can be reduced. This is because metal protrusions capable of contacting a large number (e.g., dozens) of circuit boards can be formed on one wafer for growing a plurality of LEDs 130.

[0078] In addition, compared with the case of forming protrusions 133 on the electrodes of the driving substrate 110, according to an embodiment of the present disclosure, the possibility of damage to the driving substrate 110 and the plurality of LEDs 130 can be significantly reduced during the manufacturing process. Since the materials used in the driving substrate 110 are similar to each other to the materials used in the process of forming the protrusions 133, when metal protrusions are formed on the electrodes of the driving substrate 110, at least a part of the driving substrate 110 and the LEDs 130 may be damaged during the manufacturing process. In contrast, in the wafer for manufacturing a plurality of LEDs 130, an insulating organic material for forming the protrusions 133 is not used, and the possibility of damage is low.

[0079] According to an embodiment of the present disclosure, compared with the related art of connecting the LED and the driving substrate by using conductive balls, when a defect occurs in some of the LEDs 130, it can be conveniently repaired. In particular, according to the related art of forming conductive balls on the driving substrate, there is an additional area that is convenient for repair when an LED is defective. However, since the conductive balls are formed in this area, it is difficult to replace the LED. In contrast, according to an embodiment of the present disclosure, one or more LEDs 130 including the metal layer 134 including protrusions on the flat driving substrate 110 can be easily removed and replaced individually.

[0080] In addition, according to an embodiment of the present disclosure, compared with the case of forming metal protrusions on the electrodes of the driving substrate 110, due to the high adhesion force between the plurality of LEDs 130 and the driving substrate 110, the stability of the process for manufacturing the display module 100 can be significantly improved. This is because when metal protrusions are formed on the electrodes of the driving substrate 110, the coupling between at least one second electrode 132 included in the plurality of LEDs 130 and the non-conductive film layer 140 is performed. In contrast, when metal protrusions are formed on the electrodes of the plurality of LEDs 130 according to an embodiment of the present disclosure, the contact area for performing the coupling with the non-conductive film layer 140 increases according to the metal protrusions. In the transfer process that requires precise transfer of the microchip to the driving substrate 110, the stability of the process may be very effective.

[0081] Since the range of materials that can be used in the wafer - side process for growing multiple LEDs 130 is wider than the range of materials that can be used in the process of the driving substrate 110, the display module 100 according to an embodiment of the present disclosure can exhibit better performance compared to the related art. For example, in the process of the driving substrate 110, the types of metals that can be used to prevent process damage are limited, while according to an embodiment of the present disclosure, when forming the protruding metal layer 134 on the multiple LEDs 130, a metal with higher conductivity (e.g., Au) can be used.

[0082] According to the present disclosure, compared to the related art in which an LED and the driving substrate 110 are connected by using conductive balls, the production cost of the display module 100 can be significantly reduced, and the same advantage of maintaining the coupling between the LED 130 and the driving substrate 110 stable through the elastic recovery of the conductive balls can be retained.

[0083] In addition, according to an embodiment of the present disclosure, compared to the related art in which an LED and a driving substrate are connected by using conductive balls, metal protrusions can be formed between the LED 130 and the driving substrate 110 with higher uniformity and density, and short - circuit defects caused by the phenomenon of conductive balls aggregating or connecting between electrodes can be minimized.

[0084] Figure 3 and Figure 4 show details of the protrusion 133 and the metal layer 134 according to various embodiments of the present disclosure. Figure 5 and Figure 6 is a diagram showing an LED 130 and one of the metal layers 134 formed on the protrusion 133 according to various embodiments of the present disclosure.

[0085] Specifically, Figure 3 and Figure 4 is a cross - sectional view of one of the protrusions 133 and one of the metal layers 134 according to an embodiment of the present disclosure, and Figure 5 and Figure 6 is a plan view (i.e., a top view) showing one of the LEDs 130 and one of the metal layers 134 formed on the protrusion 133.

[0086] As Figure 3 shown, the protrusion 133 according to an embodiment of the present disclosure can have a hemispherical shape, and one of the metal layers 134 can be formed on the surface of the protrusion 133 and one of the second electrodes 132 (see Figure 2 ). As Figure 4 shown, the protrusion 133 according to an embodiment of the present disclosure can have a pyramid shape, and one of the metal layers 134 can be formed on the surface of the protrusion 133 and one of the second electrodes 132 (see Figure 2 ).

[0087] Figure 3 One of the hemispherical protrusions 133 and one of the metal layers 134 shown in Figure 5 are shown in a top view. That is, a plurality of protrusions 133 having a hemispherical shape are provided on one of the second electrodes 132 (see Figure 2 ), and one of the metal layers 134 can be formed on the surfaces of the plurality of protrusions 133 and one of the second electrodes 132 (see Figure 2 ).

[0088] As Figure 6 shown, as a non-limiting example, in the red LED 130-1’, a plurality of protrusions 133 (see Figure 2 ) according to an embodiment of the present disclosure can be linearly provided on one of the second electrodes 132, and each protrusion 133 can have the form of a lying semi-cylindrical column. In addition, one of the metal layers 134 can be formed on the surfaces of the plurality of linearly arranged protrusions 133 and one of the second electrodes 132.

[0089] A plurality of protrusions 133 according to an embodiment of the present disclosure can have a so-called tapered structure, the width of which gradually narrows from bottom to top. For example, when the width of the protrusion 133 gradually decreases upward, a metal layer 134 can be easily formed on the entire surface of one of the second electrodes 132 including the regions where the plurality of protrusions 133 are provided and not provided.

[0090] According to an embodiment of the present disclosure, it may be more advantageous when the region where one of the metal layers 134 formed on the plurality of protrusions 133 is in contact with one of the first electrodes 120 is narrower and the number is larger. In particular, when the region where one of the metal layers 134 formed on the plurality of protrusions 133 is in contact with one of the first electrodes 120 has a wide shape such as a line or an edge, compared with the case where the region where one of the metal layers 134 formed on the plurality of protrusions 133 is in contact with one of the first electrodes 120 is narrower and the number is larger, the contact between one of the metal layers 134 and one of the first electrodes 120 is less likely to be formed uniformly. Therefore, the brightness and other performance aspects of each of the plurality of LEDs 130 may not be uniform. In addition, when the region where one of the metal layers 134 formed on the plurality of protrusions 133 is in contact with one of the first electrodes 120 is wide, even if dust or the like enters a part of the region, the distance between one of the metal layers 134 and one of the first electrodes 120 may become wide.

[0091] Accordingly, according to an embodiment of the present disclosure, the protrusion 133 and one of the metal layers 134 formed on the protrusion 133 can have a hemispherical shape as shown in Figure 3 and Figure 5 shown or as shown in Figure 4The pyramid shape shown allows the region where one of the metal layers 134 is in contact with one of the first electrodes 120 to have a dot shape, as opposed to the case where the region where one of the metal layers 134 is in contact with one of the first electrodes 120 has a linear shape, as Figure 6 shown.

[0092] The shape of the protrusions 133 and the metal layers 134 formed on the protrusions 133 according to an embodiment of the present disclosure is not limited to a specific shape, and the shape and size of the protrusions 133 and the metal layers 134 according to an embodiment of the present disclosure can be implemented in various shapes and sizes according to the size and structure of the LED 130.

[0093] Figure 7 is a flowchart showing a method for manufacturing the display module 100 according to an embodiment of the present disclosure. Figures 8 to 11 is a diagram showing the steps of a method for manufacturing the display module 100 according to an embodiment of the present disclosure. In the following drawings, some reference numerals of elements are omitted, and these reference numerals are only used to clearly indicate the steps indicated by the corresponding drawings, and based on the previous drawings of the present application, the omitted reference numerals can be easily understood.

[0094] The method for manufacturing the display module 100 according to an embodiment of the present disclosure may include: an operation of forming a plurality of first electrodes 120 on the driving substrate 110 (operation S710). As Figure 8 shown, a plurality of electrodes may be formed in a pre-specified region on the driving substrate 110.

[0095] The method for manufacturing the display module 100 according to an embodiment of the present disclosure may include: an operation of manufacturing a plurality of LEDs 130 (operation S720), the plurality of LEDs 130 including a plurality of semiconductor layers 131, a plurality of second electrodes 132 respectively corresponding to the plurality of first electrodes 120, a plurality of protrusions 133 formed on each of the plurality of second electrodes 132, and a plurality of metal layers 134 formed on the plurality of protrusions 133 and connected to the plurality of second electrodes 132. The order between the operation of forming the plurality of first electrodes 120 on the driving substrate 110 in operation S710 and the operation of manufacturing the plurality of LEDs 130 in step S720 may be reversed.

[0096] The operation of manufacturing the plurality of LEDs 130 may include: forming a plurality of semiconductor layers 131, a plurality of second electrodes 132, a plurality of protrusions 133, and a plurality of metal layers 134 on a growth substrate (wafer), and further including a chip-level packaging step. Refer to Figures 12 to 15 for a more detailed description of the respective operations for manufacturing the plurality of LEDs 130.

[0097] A method for manufacturing a display module 100 according to an embodiment of the present disclosure may include: an operation of forming a non-conductive film layer 140 on a substrate (S730). As Figure 9 shown, the non-conductive film layer 140 may be formed on the surface of the driving substrate 110 where a plurality of first electrodes 120 are not formed and on the surfaces of the plurality of first electrodes 120.

[0098] Specifically, the non-conductive film layer 140 may be formed on the driving substrate 110 according to a so-called lamination process. The lamination process refers to a process of covering a target object (driving substrate 110) with a layer (non-conductive film layer 140) by applying temperature and pressure. The lamination process can be used to protect the surface of the target object and improve strength and stability, and in particular, the non-conductive film layer 140 according to an embodiment of the present disclosure can be used to bring the plurality of first electrodes 120 into contact with the plurality of metal layers 134, as described below.

[0099] A method for manufacturing a display module 100 according to an embodiment of the present disclosure may include: in operation S740, transferring a plurality of LEDs 130 onto the non-conductive film layer 140. Specifically, the plurality of LEDs 130 may be transferred onto the non-conductive film layer 140 by visually aligning the plurality of first electrodes 120 formed on the driving substrate 110 with the second electrodes 132 included in the plurality of LEDs 130.

[0100] Specifically, when the steps of manufacturing the plurality of LEDs 130 and forming the non-conductive film layer 140 on the driving substrate 110 are completed, a process of transferring the plurality of LEDs 130 onto the non-conductive film layer 140 formed on the driving substrate 110 may be performed. The transfer process according to an embodiment of the present disclosure may be performed by various methods, such as an electrostatic method, an imprint method, a printing method, a metal bonding method, etc., and there is no specific limitation on the method.

[0101] As Figure 10 shown, according to the transfer process, the plurality of second electrodes 132 included in the plurality of LEDs 130 may be disposed on the corresponding plurality of first electrodes 120 in a form embedded in the non-conductive film layer 140. In a state where the transfer step is completed, the plurality of metal layers 134 formed on the plurality of protrusions 133 and the plurality of first electrodes 120 formed on the driving substrate 110 do not contact each other. Figure 10 The three LEDs 130 shown are a red LED 130-1, a green LED 130-2, and a blue LED 130-3, respectively, but according to an embodiment of the present disclosure, the number and arrangement method of the LEDs 130 for each pixel are not limited to a specific configuration.

[0102] A method of manufacturing a display module 100 according to an embodiment may include: in operation S750, performing thermocompression bonding on a non-conductive film layer 140 such that as a plurality of first electrodes 120 and a plurality of metal layers 134 are combined, the plurality of first electrodes 120 and the plurality of second electrodes 132 are connected.

[0103] Specifically, when the step of transferring a plurality of LEDs 130 onto the non-conductive film layer 140 is completed, heat and pressure are applied to the display module 100, particularly the non-conductive film layer 140, and thus, the plurality of metal layers 134 formed on the plurality of protrusions 133 and the plurality of first electrodes 120 formed on the driving substrate 110 come into contact with each other.

[0104] Then, when the non-conductive film layer 140 made of a thermosetting material is cured, the contact between the plurality of metal layers 134 formed on the plurality of protrusions 133 and the plurality of first electrodes 120 formed on the driving substrate 110 is maintained. In this case, since the plurality of protrusions 133 have an elastic restoring force to return to their original shape in a state deformed due to heat and pressure, the plurality of metal layers 134 and the plurality of first electrodes 120 can be in contact more stably.

[0105] Figure 12 is a flowchart showing a method of manufacturing an LED 130 according to an embodiment of the present disclosure. Figures 13 to 15 is a diagram showing steps of a method of manufacturing an LED 130 according to an embodiment of the present disclosure.

[0106] A method of manufacturing an LED 130 according to an embodiment may include: in operation S1210, forming a plurality of semiconductor layers 131 on a growth substrate.

[0107] Specifically, when a growth substrate is provided, a plurality of semiconductor layers 131 (e.g., an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer) may be formed on the growth substrate. The process of forming the plurality of semiconductor layers 131 may be performed by techniques such as metalorganic chemical vapor deposition (MOCVD), metalorganic chemical vapor epitaxy (MOVPE), molecular beam epitaxy (MBE), etc.

[0108] A method of manufacturing an LED 130 according to an embodiment of the present disclosure may include: in operation S1220, forming a plurality of second electrodes 132 on the plurality of semiconductor layers 131.

[0109] Specifically, although Figure 13Although not shown in detail, before forming a plurality of second electrodes 132 on the plurality of semiconductor layers 131, patterning may be performed on the regions to be etched by a photoresist, and a step of patterning the regions for forming the plurality of second electrodes 132 may be performed. Etching may be performed using wet etching or dry etching techniques or the like. Dry etching techniques such as reactive ion etching (RIE), electron cyclotron resonance (ECR), inductively coupled plasma reactive ion etching (ICP-RIE), chemically assisted ion beam etching (CAIBE), etc. may be used to perform the etching.

[0110] When the operation S1210 of forming the plurality of semiconductor layers 131 and the operation S1220 of forming the plurality of second electrodes 132 are completed, as Figure 13 shown, a basic structure of a plurality of LEDs 130 may be formed on the growth substrate. At the same time, after forming the plurality of semiconductor layers 131, the growth substrate may be removed.

[0111] A method of manufacturing a plurality of LEDs 130 according to an embodiment may include: in operation S1230, forming an insulating organic film layer on the plurality of second electrodes 132; and in operation S1240, forming a plurality of protrusions 133 by patterning the insulating organic film layer.

[0112] More specifically, a material having elastic restoring force (e.g., polyimide (PI) or epoxy resin) may be used as the material of the insulating organic film layer, and patterning of the insulating organic film layer represents a process of making the insulating organic film layer have one of various forms of the protrusions 133 as described above.

[0113] When a plurality of protrusions 133 are formed, a structure as Figure 14 shown is formed. When shown in a top view, Figure 14 one of the plurality of LEDs 130 shown in Figure 5 may be represented by the top view shown in

[0114] A method of manufacturing an LED 130 according to an embodiment of the present disclosure may include: in operation S1250, a step of forming a plurality of metal layers 134 on the plurality of protrusions 133.

[0115] Specifically, for example, the plurality of metal layers 134 may be formed of metals such as Ti, Al, Cu, Ni, Au, etc., and may be formed by a process such as physical vapor deposition (PVD).

[0116] As Figure 15 shown, when a plurality of protrusions 133 and a plurality of metal layers 134 are formed on the plurality of second electrodes 132 included in the plurality of LEDs 130, a chip-level packaging step for the plurality of LEDs 130 is performed, and then the above reference may be performed asFigure 7 and Figure 10 the transfer steps described above.

[0117] Although Figure 15 not shown in [reference], after forming the plurality of metal layers 134 in operation S1250, a step of forming a capping layer made of an oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or gold (Au) on the plurality of metal layers 134 may additionally be performed.

[0118] According to the various embodiments described above, the display module 100 connects the first electrodes 120 included in the plurality of LEDs 130 to the second electrodes 132 formed on the driving substrate 110 through the protrusions 133 and the metal layers 134 included in the plurality of LEDs 130, so that the plurality of LEDs 130 are stably connected to the driving substrate 110, and the performance stability of the display module 100 and the manufacturing process efficiency of the display module 100 can be significantly improved.

[0119] Each component (e.g., module or program) according to one or more embodiments may consist of one or more objects, and some of the above sub-components may be omitted, or other sub-components may also be included in the embodiments. Alternatively or additionally, some components (e.g., modules or programs) may be integrated into one entity to perform the same or similar functions as each corresponding component performed before integration. Furthermore, various features from different embodiments may be combined.

[0120] According to an embodiment, the operations performed by a module, program, or other component may be executed sequentially, in parallel, repeatedly, or in a heuristic manner, or at least some operations may be executed in a different order, some operations may be omitted, or other operations may be added.

[0121] Although the non-limiting exemplary embodiments of the present disclosure have been shown and described above with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and details may be made thereto without departing from the spirit and scope of the present disclosure.

Claims

1. A display module, comprising: A driving substrate; A plurality of first electrodes on the driving substrate; A plurality of light emitting diodes LED, comprising: A plurality of semiconductor layers, A plurality of second electrodes respectively corresponding to the plurality of first electrodes, A plurality of protrusions on each of the plurality of second electrodes, and A plurality of metal layers on the plurality of protrusions, each metal layer in the plurality of metal layers being connected to one of the plurality of second electrodes; and A non-conductive film layer between the driving substrate and the plurality of LEDs, Wherein, the plurality of first electrodes and the plurality of second electrodes are connected through the plurality of metal layers.

2. The display module according to claim 1, wherein, By thermocompression bonding to the non-conductive film layer to bring the plurality of first electrodes into contact with the plurality of metal layers, the plurality of first electrodes and the plurality of second electrodes are connected.

3. The display module according to claim 1, wherein, The non-conductive film layer is black.

4. The display module according to claim 1, wherein, The plurality of protrusions include a polymer having elastic restoring force.

5. The display module according to claim 1, wherein, The plurality of protrusions include one of the following shapes: hemispherical shape, conical shape, pyramid shape, triangular prism shape with a cross-section in contact with one of the plurality of second electrodes, and semi-cylindrical shape including a rectangular surface in contact with one of the plurality of second electrodes.

6. The display module according to claim 1, wherein, The plurality of LEDs further include a capping layer formed on the plurality of metal layers to prevent oxidation of the plurality of metal layers.

7. The display module according to claim 6, wherein, The capping layer includes at least one of indium tin oxide ITO, indium zinc oxide IZO, and gold Au.

8. The display module according to claim 1, wherein, The plurality of LEDs are flip-chip type LEDs, and each flip-chip type LED has a horizontal length and a vertical length of not less than 1 μm and not more than 100 μm.

9. A method of manufacturing a display module, the method comprising: Forming a plurality of first electrodes on a driving substrate including a circuit; Manufacturing a plurality of light emitting diodes LED, wherein the plurality of LEDs include a plurality of semiconductor layers, a plurality of second electrodes respectively corresponding to the plurality of first electrodes, a plurality of protrusions on each of the plurality of second electrodes, and a plurality of metal layers on the plurality of protrusions, and each metal layer in the plurality of metal layers is connected to one of the plurality of second electrodes; Forming a non-conductive film layer on the driving substrate; Transferring the plurality of LEDs onto the non-conductive film layer; And Performing thermocompression bonding on the non-conductive film layer such that the plurality of first electrodes and the plurality of second electrodes are connected by bringing the plurality of first electrodes and the plurality of metal layers into contact with each other.

10. The method according to claim 9, wherein, Manufacturing the plurality of LEDs includes: Forming the plurality of semiconductor layers on a growth substrate; Forming the plurality of second electrodes on the plurality of semiconductor layers; Forming an insulating organic film layer on the plurality of second electrodes; Forming the plurality of protrusions by patterning the insulating organic film layer; and Forming the plurality of metal layers on the plurality of protrusions.

11. The method according to claim 9, wherein The non-conductive film layer is black.

12. The method according to claim 9, wherein The plurality of protrusions include a polymer having elastic restoring force.

13. The method according to claim 9, wherein The plurality of protrusions include one of the following shapes: hemispherical shape, conical shape, pyramid shape, triangular prism shape with a cross-section in contact with one of the plurality of second electrodes, and semi-cylindrical shape with a rectangular cross-section in contact with one of the plurality of second electrodes.

14. The method according to claim 10, wherein, Fabricating the plurality of LEDs includes: forming a capping layer on the plurality of metal layers to prevent oxidation of the plurality of metal layers.

15. The method according to claim 14, wherein The capping layer includes at least one of indium tin oxide (ITO), indium zinc oxide (IZO), and gold (Au).

Images