Patent Publication Number: US-11641010-B2

Title: Light-emitting device, manufacturing method thereof and display module using the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a light-emitting device and a method of manufacturing the same, and more particularly to a light-emitting device including a connection structure of a specific structure and a method of manufacturing the same. 
     DESCRIPTION OF BACKGROUND ART 
     Light-Emitting Diode (LED) has low power consumption, low heat generation, long operating lifetime, impact resistance, small size and fast response. It is widely used in various fields where light-emitting elements are required. For example, vehicles, household electric appliances, displays, and lighting fixtures. 
     LEDs are a type of monochromatic light and therefore are well suitable for being pixels in displays. For example, it can be used as a pixel for an outdoor or indoor display. In order to improve the resolution, it is necessary to transfer more LEDs as pixels to the target substrate, and the yield improvement of the electrical connection between the LEDs and the substrate becomes a big challenge. 
     SUMMARY OF THE DISCLOSURE 
     A light-emitting device practiced in accordance with the present disclosure comprises a carrier including a first electrically conductive region and a light-emitting element. The light-emitting includes a first light-emitting layer and a first contact electrode formed under the first light-emitting layer. The first contact electrode is corresponded to the first electrically conductive region. A connection structure includes a first electrical connection portion and a protective portion surrounding the first contact electrode and the first electrical connection portion and the first electrical connection portion is electrically connected with the first electrical portion and the first contact electrode. The first electrical connection portion includes an upper portion, a lower portion and a neck portion located between the upper portion and the lower portion. The lower portion has a width wider than that of the upper portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  shows a cross-sectional view of a light-emitting element in accordance with an embodiment of the present disclosure. 
         FIG.  1 B  shows a cross-sectional view of a light-emitting element in accordance with another embodiment of the present disclosure. 
         FIG.  1 C  shows a cross-sectional view of a light-emitting element in accordance with another embodiment of the present disclosure. 
         FIG.  2 A  shows a cross-sectional view of a light-emitting unit in accordance with an embodiment of the present disclosure. 
         FIG.  2 B  shows a cross-sectional view of a light-emitting unit in accordance with another embodiment of the present disclosure. 
         FIG.  2 C  shows a cross-sectional view of a light-emitting unit in accordance with another embodiment of the present disclosure. 
         FIGS.  3 A to  3 E  show the diagrams of manufacturing process of a light-emitting device in accordance with an embodiment of the present disclosure. 
         FIGS.  3 A to  3 C and  3 F to  3 J  show the diagrams of manufacturing process of a light-emitting device in accordance with another embodiment of the present disclosure. 
         FIGS.  4 A to  4 E  show the diagrams of manufacturing process of a light-emitting device in accordance with another embodiment of the present disclosure. 
         FIGS.  5 A to  5 D  show the partial structural views of a light-emitting device in accordance with an embodiment of the present disclosure. 
         FIG.  6    shows a top view of a light-emitting module in accordance with an embodiment of the present disclosure. 
         FIGS.  7 A to  7 D  show the diagrams of a manufacturing process for repairing a light-emitting module in accordance with an embodiment of the present disclosure. 
         FIGS.  7 A and  7 E to  7 G  show the diagrams of a manufacturing process of repairing a light-emitting module in accordance with another embodiment of the present disclosure. 
         FIGS.  8 A to  8 G  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with an embodiment of the present disclosure. 
         FIGS.  9 A to  9 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  10 A to  10 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  11 A to  11 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIG.  12    shows a transfer device in accordance with an embodiment of the present disclosure. 
         FIGS.  13 A and  13 B  show the schematic views of the connection structure before and after curing in the light-emitting device in accordance with an embodiment of the present disclosure. 
         FIGS.  14 A and  14 B  show the schematic views of the connection structure before and after curing in the light-emitting device in accordance with another embodiment of the present disclosure. 
         FIGS.  15 A to  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  15 A,  15 B,  15 E, and  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  15 A,  15 B,  15 F, and  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  16 A to  16 C  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  16 D,  16 E, and  16 C  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIG.  17 A  shows a bottom view of a light-emitting element in accordance with an embodiment of the present disclosure. 
         FIG.  17 B  shows a bottom view of a light-emitting element covering the connection structure in accordance with an embodiment of the present disclosure. 
         FIG.  17 C  shows a bottom view of a target substrate covering the connection structure in accordance with an embodiment of the present disclosure. 
         FIGS.  18 A to  18 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  18 A,  18 B,  18 E to  18 F  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  18 A,  18 G to  18 I  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. 
         FIGS.  19 A to  19 B  show the schematic views of the connection structure before and after curing in the light-emitting device disclosed in  FIGS.  18 A to  18 D . 
         FIG.  19 C  shows a top view of a light-emitting device disclosed in  FIG.  18 D . 
         FIG.  19 D  shows a top view of a light-emitting device disclosed in  FIG.  18 F . 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE 
       FIG.  1 A  is a cross-sectional view of a light-emitting element  100 A in accordance with an embodiment of the present disclosure.  FIG.  1 B  shows a cross-sectional view of a light-emitting element  100 B in accordance with another embodiment of the present disclosure.  FIG.  1 C  shows a cross-sectional view of a light-emitting element  100 C in accordance with another embodiment of the present disclosure. Referring to  FIG.  1 A , the light-emitting element  100 A includes a light-emitting unit  120  and bumps  142   a  and  144   a . In an embodiment, the light-emitting unit  120  includes a light-emitting stack  122  and contact electrodes  1241 ,  1242 . The bumps  142   a  and  144   a  are respectively electrically connected to the contact electrodes  1241  and  1242 . 
     The light-emitting stack  122  can emit light after being provided with external power (not shown). The bumps  142   a ,  144   a  can serve as a bridge between the light-emitting stack  122  and the external power and can be used as a part of the connection structure for the light-emitting device. In an embodiment, the bump  142   a  is directly formed under the contact electrode  1241  and the width of the upper surface of the bump  142   a  near the contact electrode  1241  is wider than the width of the lower surface of the bump  142   a  away from the contact electrode  1241 . In an embodiment, the width of the bump  142   a  is gradually narrowed from the upper surface to the lower surface so the shape can be a cone shape or a pyramid shape. In an embodiment, the bump  142   a  has a structure such as a needle or a tube near the lower surface. In an embodiment, the material of the bump  142   a  is an electrically conductive material such as metal or electrically conductive polymer. In an embodiment, the metal comprises gold, copper, gold alloy or copper alloy. The shape or material of the bump  144   a  and the bump  142   a  may be the same or similar. 
     Referring to  FIG.  1 B , the light-emitting element  100 B includes a light-emitting unit  120  and bumps  142   b ,  144   b . The difference from the light-emitting element  100 A is in the shape of the bumps  142   b ,  144   b . The shape of the bumps  142   b ,  144   b  may have a flat region on the lower surface, for example, truncated cone shape or truncated pyramid shape. 
     Referring to  FIG.  1 C , the light-emitting element  100 C includes a light-emitting unit  120  and bumps  142   c ,  144   c . The difference from the light-emitting element  100 A is in the bumps  142   c ,  144   c . In an embodiment, the bumps  142   c ,  144   c  are separately formed as a film under the lower surface of the contact electrodes  1241 ,  1242 . In an embodiment, the bumps  142   c ,  144   c  have a thickness T1 about 1 to 12 microns. In another embodiment, the bumps  142   c ,  144   c  have a thickness T1 about 2 to 10 microns. The material of the bumps  142   c ,  144   c  may be metal having a low melting point or alloy having a low liquidus melting point. Moreover, the above-mentioned metal is, for example, tin (Sn) or indium (In), and the above-mentioned alloy is, for example, a gold-tin alloy. In an embodiment, each of the bumps  142   c ,  144   c  has a flat bottom surface and the light-emitting element  100 C can be placed smoothly on the carrier during subsequent bonding process with the carrier. 
       FIG.  2 A  shows a cross-sectional view of a light-emitting unit  120 A in accordance with an embodiment of the present disclosure.  FIG.  2 B  shows a cross-sectional view of a light-emitting unit  120 B in accordance with another embodiment of the present disclosure.  FIG.  2 C  shows a cross-sectional view of a light-emitting unit  120 C in accordance with another embodiment of the present disclosure. The light-emitting unit  120  shown in  FIGS.  1 A- 1 C  may be one of the light-emitting units  120 A,  120 B or  120 C. Referring to  FIG.  2 A , the light-emitting unit  120 A includes conductive pads  1211 A,  1212 A, a light-emitting stack  122 , an insulating layer  123 A (also referred to as a first insulating layer), contact electrodes  1241 A,  1242 A, and a carrier substrate  126 A. In particular, the light-emitting stack  122  sequentially includes the first semiconductor  1221 , the light emitting layer  1222  and the second semiconductor  1223  from bottom to top, and light-emitting stack  122  is located below the carrier substrate  126 A. The conductive pads  1211 A and  1212 A is respectively electrically connected to the first semiconductor  1221  and the second semiconductor  1223 . The insulating layer  123 A is located below the light-emitting stack  122  and between the two conductive pads  1211 A,  1212 A. The contact electrodes  1241 A and  1242 A are respectively electrically connected to the conductive pads  1211 A and  1212 A. Contact electrodes  1241 A,  1242 A have a larger bottom surface area or width relative to conductive pads  1211 A,  1212 A so that be easier connected to external electrodes (not shown). 
     The light-emitting unit  120 A can be a light-emitting diode die. In an embodiment, the light-emitting unit  120 A is a red light emitting diode die, which can be powered through a power source and emit a light (or referred as first light), and the dominant wavelength or peak wavelength of the light is between 600 nm and 660 nm. In another embodiment, the light-emitting unit  120 A is a green light emitting diode die and emit a light (or referred as first light) that the dominant wavelength or peak wavelength is between 510 nm and 560 nm. In another embodiment, the light-emitting unit  120 A is a blue light emitting diode die and emit a light (or referred as first light) that the dominant wavelength or peak wavelength is between 430 nm and 480 nm. In an embodiment, the carrier substrate  126 A of the light-emitting unit  120 A is a growth substrate for epitaxial growth of the light-emitting stack  122 . The material of the growth substrate, for example, is sapphire. In another embodiment, the carrier substrate  126 A is a transparent ceramic substrate, and is connected to the light-emitting stack  122  through a bonding layer (not shown). The material of the transparent ceramic substrate, for example, is alumina (aluminum oxide). The material of the conductive pads  1211 A,  1212 A may comprise a highly conductive metal such as aluminum. The material of the contact electrodes  124   a ,  124   b  may comprise a highly conductive metal or alloy, such as aluminum, copper, gold or gold-tin alloy. 
     Referring to  FIG.  2 B , the light-emitting unit  120 B includes conductive pads  1211 B,  1212 B, a light-emitting stack  122 , contact electrodes  1241 B,  1242 B, a carrier substrate  126 B and a wavelength conversion layer  128 B. In an embodiment, the light-emitting stack  122  is electrically coupled to the contact electrodes  1241 B and  1242 B. The carrier substrate  126 B is located below the light-emitting stack layer  122  and surrounds the contact electrodes  1241 B,  1242 B. In an embodiment, the growth substrate for epitaxial growing the light-emitting stack  122  is partially or completely removed, thus the carrier substrate  126 B is not a growth substrate. Moreover, the wavelength conversion layer  128 B is located above the light-emitting stack  122 . In an embodiment, the wavelength conversion layer  128 B also covers a portion of the surface of the carrier substrate  126 B. 
     In an embodiment, in the light-emitting unit  120 B, the contact electrodes  1241 B and  1242 B are in the shape of pillar. The material of the carrier substrate  126 B can be resin, such as epoxy resin. In an embodiment, the wavelength conversion layer  128 B includes a binder (not shown, a first binder) and a plurality of wavelength conversion particles (not shown) dispersed in the binder, wherein the wavelength conversion particles can absorb the first light emitted from the light-emitting stack  122  and partially or totally convert the first light into a second light having the wavelength or spectrum different from the first light. In an embodiment, the wavelength conversion particles absorb the first light, such as blue or UV light, and then convert the first light to the second light (green light) having a dominant or peak wavelength between 510 nm and 560 nm. In another embodiment, the wavelength conversion particles absorb the first light, such as blue or UV light, and then convert the first light to the second light (red light) having a dominant or peak wavelength between 600 nm and 660 nm. The material of the wavelength conversion particles can comprise inorganic phosphor, organic fluorescent colorant, semiconductor, or a combination of the above-mentioned materials. The material of semiconductor comprises nano crystal semiconductor material, such as quantum-dot luminescent material. 
     Referring to  FIG.  2 C , the light-emitting unit  120 C includes a light-emitting stack  122 , contact electrodes  1241 C and  1242 C, a light-blocking fence  125 C, a carrier substrate  126 C, and a wavelength conversion layer  128 C. In an embodiment, the light-emitting stack  122  is electrically connected to the contact electrodes  1241 C and  1242 C. The carrier substrate  126 C is located above the light-emitting stack  122 . The wavelength conversion layer  128 C is located above the carrier substrate  126 C. The light-blocking fence  125 C surrounds the light-emitting stack  122 , carrier substrate  126 C and the wavelength conversion layer  128 C. The light-blocking fence  125 C can prevent the first light emitted by the light-emitting stack  122  and/or the second light emitted by the wavelength conversion layer  128 C being emitted from the sides of the light-emitting unit  120 C that may cause crosstalk between the neighboring light-emitting units. 
     The light-blocking fence  125 C can include a binder (not shown, a second binder) and a plurality of light-absorbing particles or light-reflecting particles dispersed in the binder. The material of the light-absorbing particles can be carbon black. The material of the light-reflecting particles can be titanium oxide, zinc oxide, aluminum oxide, barium sulfate, or calcium carbonate. 
       FIGS.  3 A to  3 E  show the diagrams of manufacturing process of a light-emitting device  300 A in accordance with an embodiment of the present disclosure. Referring to  FIG.  3 A , a carrier is provided. The carrier includes an insulating layer  322  (also referred as a second insulating layer) and a plurality of electrically conductive regions  323 ,  324 . In an embodiment, the electrically conductive regions  323 ,  324  are formed on the insulating layer  322 . In one embodiment, each of the electrically conductive regions  323 ,  324  has a pair of electrically conductive pads respectively correspond to the contact electrodes  1241 ,  1242  of the light-emitting unit  120 . In addition, the electrically conductive regions  323 ,  324  may be electrically separated or electrically connected to each other. 
     The material of the insulating layer  322  may be epoxy resin, BT (Bismaleimide Triazine) resin, polyimide resin, composite material of epoxy resin and glass fiber, or composite material of BT resin and glass fiber. The material of the electrically conductive regions  323 ,  324  can be metal such as copper, tin, aluminum, silver, or gold. In an embodiment, when the light-emitting device  300 A is used as a pixel in a display device, a light-absorbing layer (not shown) can be formed on the surface of the insulating layer  322  to increase the contrast, for example, a black coating. 
     Referring to  FIG.  3 B , the glues  340   a ′,  340   b′  containing the resins  341   a ,  341   b  and the electrically conductive particles  342   a ,  342   b  are respectively formed on and around the electrically conductive regions  323 ,  324 . In an embodiment, the way for forming the glues  340   a ′,  340   b′  is by a patterned fixture, wherein the patterned fixture is, for example, a stencil or a screen. 
     In an embodiment, the plurality of electrically conductive particles  342   a  is dispersed in the resin  341   a . It is understood that the plurality of electrically conductive particles  342   b  is dispersed in the resin  341   b . The materials of the resins  341   a  and  341   b  include a thermosetting polymer and a flux. The thermosetting polymer can be epoxy resin. The material of the electrically conductive particles  342   a ,  342   b  may be gold, silver, copper, or tin alloy. In an embodiment, the material of the electrically conductive particles may be metal having a low melting point or alloy having a low liquidus melting point. In an embodiment, the metal having a low melting point or the alloy having a low liquidus melting point has a melting point or liquidus temperature below 210° C. In another embodiment, the metal having a low melting point or the alloy having a low liquidus melting point has a melting point or liquidus temperature below 170° C. The material of the alloy having a low liquidus melting point may be tin indium alloy or tin antimony alloy. 
     Referring to  FIG.  3 C , the resins  341   a ,  341   b  in the glues  340   a ′,  340   b′  are cured to form the protective portions  343   a ,  343   b  in the connection structures  340   a ,  340   b . In this step, the electrically conductive particles  342   a  and  342   b  are melted to form lower portions  3442   a  and  3442   b  of the electrical connection portions in the connection structures  340   a  and  340   b . The curing method can be heating. In an embodiment, during the curing phase, the adhesiveness of the resins  341   a ,  341   b  drops in the beginning and then rises so the electrically conductive particles  342   a ,  342   b  gather around the electrically conductive regions  323 ,  324 . The electrically conductive particles  342   a ,  342   b  are gathered in the melting state. In an embodiment, the curing temperature is above 140° C. 
     Referring to  FIG.  3 D , a light-emitting element  100 A- 1  is provided. In an embodiment, one light-emitting element  100 A- 1  corresponds to one electrically conductive region  323  and one connection structure  340   a . In another embodiment, a plurality of light-emitting elements  100 A- 1 ,  100 A- 2  simultaneously correspond to the plurality of electrically conductive regions  323 ,  324  and the connection structures  340   a ,  340   b.    
     Referring to  FIG.  3 E , the bumps  142   a ,  144   a  of the light-emitting element  100 A- 1  are connected to the electrically conductive portion  323  through the lower portion  3442   a  of the electrical connection portion to constitute the light-emitting device  300 A. In an embodiment, the bumps  142   a ,  144   a  of the light-emitting element  100 A- 1  are moved downward by an external force to penetrate the protective portion  343   a  until the lower portion  3442   a  of the electrical connection portion is in contact with the bumps  142   a ,  144   a , which become the upper portion  3441   a  of the electrical connection portion in the connection structure  340   a . In addition, a neck portion  3443   a  is formed between the upper portion  3441   a  of the electrical connection portion and the lower portion  3442   a  of the electrical connection portion. In an embodiment, the upper portion  3441   a  of the electrical connection portion is different from the lower portion  3442   a  of the electrical connection portion in terms of the material composition. For example, the upper portion  3441   a  of the electrical connection portion contains copper element and the lower portion  3442   a  of the electrical connection portion contains tin element. Similarly, the bumps  142   a ,  144   a  of the light-emitting element  100 A- 2  are connected to the electrically conductive region  324  by the lower portion  3442   b  of the electrical connection portion to constitute another light-emitting device. In an embodiment, the light-emitting element  100 A- 1  or the light-emitting element  100 A- 2  can be individually incorporated in a single light-emitting device  300 A. In another embodiment, the light-emitting element  100 A- 1  and the light-emitting element  100 A- 2  can be incorporated together in a light-emitting device. In an embodiment, the insulating layer  322  can be cut in a subsequent step such that the light-emitting device  300 A is physically separated from the other light-emitting device. In another embodiment, the insulating layer  322  does not need to be cut such that the light-emitting device  300 A and the other light-emitting device share the insulating layer  322 . 
       FIGS.  3 A to  3 C and  3 F to  3 J  show the diagrams of manufacturing process of a light-emitting device  300 B in accordance with another embodiment of the present disclosure. In  FIG.  3 C , after the steps of forming the protective portions  343   a ,  343   b  of the connection structures  340   a ,  340   b  and the lower portions  3442   a ,  3442   b  of the electrical connection portion, the following steps from  FIGS.  3 F to  3 H  show that a plurality of depressed portions  347   a ,  347   b  are formed in the connection structures  340   a ,  340   b  through a jig  360 . In an embodiment, referring to  FIG.  3 F , a jig  360  having a plurality of convex portions  361  is provided. The shape of the convex portion is, for example, pointed. The respective convex portions  361  of the jig  360  are respectively aligned with the lower portions  3442   a ,  3442   b  of the electrical connection portions in the connection structures  340   a ,  340   b . Referring to  FIG.  3 G , a plurality of convex portions in the jig  360  are inserted into the protective portion  343   a  until the lower portions  3442   a ,  3442   b  of the electrical connection portion are in contact with the convex portions. Referring to  FIG.  3 H , the jig  360  is upwardly separated from the connection structures  340   a ,  340   b  to form a plurality of depressed portions  347   a ,  347   b . The plurality of depressed portions  347   a ,  347   b  respectively corresponds to the electrically conductive regions  323 ,  324  and the lower portions  3442   a ,  3442   b  of the electrical connection portion. Referring to  FIG.  3 I , the bumps  142   b ,  144   b  of the light-emitting elements  100 B- 1 ,  100 B- 2  are respectively aligned with the lower portion  3442   a  of the electrical connection portion and the electrically conductive region  323 . Referring to  FIG.  3 J , the bumps  142   b ,  144   b  of the light-emitting element  100 B- 1  are electrically connected to the electrically conductive portion  323  through the lower portion  3442   a  of the electrical connection portion to constitute the light-emitting device  300 B. Similarly, the bumps  142   a  and  144   a  of the light-emitting element  100 B- 2  are connected to the electrically conductive region  324  through the lower portion  3442   b  of the electrical connection portion to constitute another light-emitting device. In an embodiment, the light-emitting element  100 B- 1  and the light-emitting element  100 B- 2  can be incorporated together in a light-emitting device. In another embodiment, the light-emitting element  100 B- 1  or the light-emitting element  100 B- 2  can be individually incorporated in a single light-emitting device. 
       FIGS.  4 A to  4 E  show the diagrams of manufacturing process of a light-emitting device  400 A in accordance with another embodiment of the present disclosure. Referring to  FIG.  4 A , a carrier is provided. The carrier includes an insulating layer  322  and a plurality of electrically conductive regions  323 ,  324 . The structure, function and material of the insulating layer  322  and the plurality of electrically conductive regions  323 ,  324  can be referred to the corresponding paragraphs of  FIG.  3 A . 
     Referring to  FIG.  4 B , the glues  440   a ′,  440   b′  are respectively formed on and around the electrically conductive regions  323 ,  324 . In an embodiment, the way for forming the glues  440   a ′,  440   b′  is by a patterned jig, wherein the patterned jig is, for example, a stencil or a screen. In an embodiment, the glues  440   a ′,  440   b′  contain resins. The material of the resins includes a thermosetting polymer and a flux. The thermosetting polymer can be epoxy resin. In another embodiment, the glues  440   a ′,  440   b′  comprises resins and light-reflecting particles dispersed in the resins. The material of the light-reflecting particles may be titanium oxide, zinc oxide, aluminum oxide, barium sulfate or calcium carbonate. 
     Referring to  FIG.  4 C , light-emitting elements  100 C- 1  and  100 C- 2  are provided. The bumps  142   c - 1 ,  144   c - 1  of the light-emitting element  100 C- 1  are aligned with the electrically conductive region  323  and the bumps  142   c - 2 ,  144   c - 2  of the light-emitting element  100 C- 2  are aligned with the electrically conductive region  324 . Referring to  FIG.  4 D , the bumps  142   c - 1 ,  144   c - 1  of the light-emitting element  100 C- 1  penetrate through the glue  440   a ′ and are in contact with the electrically conductive regions  323 . Similarly, the bumps  142   c - 2 ,  144   c - 2  of the light-emitting element  100 C- 2  penetrate the glue  440   b′  and are in contact with the electrically conductive regions  324 . 
     Referring to  FIG.  4 E , the bumps  142   c - 1 ,  144   c - 1 ,  142   c - 2 ,  144   c - 2  are melted. Therefore, the bumps  142   c - 1 ,  144   c - 1  are connected to the electrically conductive regions  323  to form the electrical connection portions  441 ,  442  in the connection structures  440   a ,  440   b . Similarly, the bumps  142   c - 2 ,  144   c - 2  are connected to the electrically conductive regions  324  to form electrical connection portions  444 ,  445 . In this step, in addition to melting the bumps  142   c - 1 ,  144   c - 1 ,  142   c - 2 ,  144   c - 2 , the glues  440   a ′,  440   b′  are cured to form the protective portions  443   a ,  443   b  in the connection structures  440   a ,  440   b . After melting the bumps  142   c - 1 ,  144   c - 1  of the light-emitting element  100 C- 1  and curing the glue  440   a ′, the light-emitting device  400 A are formed. Similarly, after melting the bumps  142   c - 2 ,  144   c - 2  of the light-emitting element  100 C- 2  and curing the glue  440   a ′, another light-emitting device  400 B are formed. In an embodiment, the connection structures  440   a ,  440   b  further include light-reflecting particles (not shown) dispersed in the protective portions  443   a ,  443   b  so the reflectance of the connection structures  440   a ,  440   b  for the light emitted from the light-emitting elements  100 C- 1 ,  100 C- 2  can be increased. 
       FIG.  5 A  shows a partial structural view of the connection structure  440   b  in the light-emitting device  400 B shown in  FIG.  4 E  in accordance with an embodiment of the present disclosure. An electrical connection portion  444 A is located between the contact electrode  1241 C- 2  of the light-emitting element  100 C- 2  and the electrically conductive region  324  on the insulating layer  322 . In an embodiment, the electrical connection portion  444 A includes an upper portion  4441 A, a neck portion  4443 A and a lower portion  4442 A. The neck portion  4443 A is located between the upper portion  4441 A and the lower portion  4442 A. In an embodiment, the upper portion  4441 A of the electrical connection portion has the same material composition with the lower portion  4442 A of the electrical connection portion, for example, both contain tin. In an embodiment, the width of the neck portion  4443 A is less than the width of the upper portion  4441 A. In an embodiment, the width of the upper portion  4441 A is less than the width of the lower portion  4442 A. In an embodiment, the electrical connection portion  444 A has a thickness T2 less than 5 microns. In another embodiment, the electrical connection portion  444 A has a thickness T2 greater than 3 microns. In another embodiment, the electrical connection portion  444 A has a thickness T2 between 1 micron and 4 microns. In an embodiment, at least a portion of the bottom surface of the upper portion  4441 A is substantially planar. In an embodiment, the distance between the bottom surfaces of the contact electrode  1241 C- 2  to the plane of the bottom surface of the upper portion  4441 A is less than 1 micron. In another embodiment, the distance between the bottom surfaces of the contact electrode  1241 C- 2  to the plane of the bottom surface of the upper portion  4441 A is less than 0.5 micron. In an embodiment, the protective portion  443   b  surrounds the electrical connection portion  444 A. In an embodiment, the protective portion  443   b  covers the contact electrode  1241 C- 2 , the electrical connection portion  444 A and the electrically conductive region  324 . The protective portion  443   b  can protect the contact electrode  1241 C- 2 , the electrical connection portion  444 A, and/or the electrically conductive region  324  so that the moisture or oxygen in the environment can be kept away from the contact electrode  1241 C- 2 , the electrical connection portion  444 A, and/or the electrically conductive region  324 . In addition, the protective portion  443   b  can avoid the problem that the electrical connection portion  444 A is short-circuited or open-circuited due to the connection portion  444 A melted in high temperature environment. 
     Referring to  FIG.  5 A , in an embodiment, all the upper portion  4441 A, the neck portion  4443 A and the lower portion  4442 A contain gold element. In an embodiment, the upper portion  4441 A, the neck portion  4443 A and the lower portion  4442 A contain gold element and tin element. In an embodiment, the content of the gold element in the area A1 of the contact electrode  1241 C- 2  and the upper portion  4441 A is greater than that in the area A2 of the electrically conductive region  324  and the lower portion  4442 A. That means the atomic percentage of the gold element in the area A1 of the contact electrode  1241 C- 2  and the upper portion  4441 A is larger than the atomic percentage of the gold element in the area A2 of the lower portion  4442 A. The above-mentioned elements can be analyzed by Energy-dispersive X-ray spectroscopy (EDX). 
       FIG.  5 B  shows a partial structural view of the connection structure  440   b  in the light-emitting device  400 B shown in  FIG.  4 E  in accordance with an embodiment of the present disclosure. Different from  FIG.  5 A , the electrical connection portion  444 B of the connection structure  440   b  has no neck portion. In an embodiment, the width of the electrical connection portion  444 B is gradually widened from the contact electrode  1241 C- 2  toward the electrically conductive region  324 . The thickness T3 of the electrical connection portion  444 B is between 1 micron and 3 microns. 
       FIG.  5 C  shows a partial structural view of the connection structure  440   b  in the light-emitting device  400 B shown in  FIG.  4 E  in accordance with an embodiment of the present disclosure. Being different from  FIG.  5 A , each of the two edges of the electrical connection portion  444 C respectively has thickness T4 and T5, and the thickness T4 and T5 are different. Besides, the thickness T4 is smaller than the thickness T5. The shape of left side having thickness T5 of the electrical connection portion  444 C is similar to that shown in  FIG.  5 A  and has a neck portion. The shape of right side having thickness T4 of the electrical connection portion  444 C is similar to that shown in  FIG.  5 B  and does not have neck portion. 
       FIG.  5 D  shows a partial structural view of the connection structure  440   b  in the light-emitting device  400 B shown in  FIG.  4 E  in accordance with an embodiment of the present disclosure. There is a hole  444   d  in the electrical connection portion  444 D. The electrical connection portion  444 D can include a single hole or multiple holes  444   d . The shape of the hole  444   d  may be regular or irregular. Regular shape can be round, oval or polygonal. 
       FIG.  6    shows a top view of a light-emitting module  600  in accordance with an embodiment of the present disclosure. In an embodiment, the light-emitting module  600  includes a first pixel  610  and a second pixel  620 . It can be understood that the number of pixels depends on the requirements of the light-emitting module  600 , and only two pixels in the light-emitting module  600  are shown here. The first pixel  610  includes six sub-pixel blocks  611   a ,  611   b ,  612   a ,  612   b ,  613   a ,  613   b . The sub-pixel blocks  611   a ,  611   b ,  612   a ,  612   b ,  613   a ,  613   b  can be individually provided for disposition of the light-emitting elements  614   a ,  614   b ,  615   a ,  615   b ,  616   a ,  616   b . The structure of the light-emitting elements  614   a ,  614   b ,  615   a ,  615   b ,  616   a ,  616   b  may be the above-described light-emitting element  100 A, light-emitting element  100 B, light-emitting element  100 C, or a combination thereof, or any suitable light-emitting element. The sub-pixel block  611   a  and the sub-pixel block  611   b  are first group. The sub-pixel block  612   a  and the sub-pixel block  612   b  are second group. The sub-pixel block  613   a  and the sub-pixel block  613   b  are third group. One group having two sub-pixel blocks provides a backup function. When a sub-pixel block fails to operate during testing or the performance cannot meet the requirements, such as insufficient brightness or color point shift, another sub-pixel block can be provided to another light-emitting element during the subsequent repair step. Therefore, not all of the sub-pixel blocks  611   a ,  611   b ,  612   a ,  612   b ,  613   a , and  613   b  have the light-emitting elements  614   a ,  614   b ,  615   a ,  615   b ,  616   a , and  616   b . In one embodiment, only the light-emitting elements  614   a ,  615   a ,  616   a  are respectively placed in the sub-pixel blocks  611   a ,  612   a ,  613   a  in the beginning. When the test results of the light-emitting elements  614   a ,  615   a ,  616   a  are all normal, the light-emitting elements  614   b ,  615   b ,  616   b  are no longer placed in the sub-pixel blocks  611   b ,  612   b ,  613   b . If the light-emitting element  614   a  is abnormal, the light-emitting element  614   a  will not be turned on, and replaced by the light-emitting element  614   b . The mechanism for light-emitting elements  615   a ,  616   a  is also similar to the condition of the light-emitting element  614   a . Similarly, the second pixel  620  includes six sub-pixel blocks  621   a ,  621   b ,  622   a ,  622   b ,  623   a ,  623   b . The sub-pixel blocks  621   a ,  621   b ,  622   a ,  622   b ,  623   a ,  623   b  can be individually provided for disposition of the light-emitting elements  624   a ,  624   b ,  625   a ,  625   b ,  626   a ,  626   b . The sub-pixel block in the second pixel  620  and the light-emitting element have substantially the same function with the first pixel  610 . 
       FIGS.  7 A to  7 D  show the diagrams of a manufacturing process for repairing a light-emitting module in accordance with an embodiment of the present disclosure. Referring to  FIG.  7 A , a carrier is provided. The carrier includes an insulating layer  722  (a second insulating layer) and a plurality of electrically conductive regions  723 ,  724 . The structure, function and material of the insulating layer  722  and the plurality of electrically conductive regions  723 ,  724  can be referred to the corresponding paragraphs of  FIG.  3 A . A light-emitting element  614   a  is formed on the electrically conductive regions  724  of the carrier. In an embodiment, the light-emitting element  614   a  is electrically connected to the electrically conductive regions  724 , and is electrically connected through solder  742 . In other embodiments, the manufacturing process of the electrical connection between the light-emitting element  614   a  and the electrically conductive regions  724  can be any of the above-mentioned paragraphs of  FIGS.  3 A to  4 E . At this time, the electrically conductive regions  723  are exposed. After testing the light-emitting element  614   a , the light-emitting element  614   a  is considered abnormal. Referring to  FIG.  7 B , a glue  340 ′ containing resin  341  and electrically conductive particles  342  is formed on and around the electrically conductive regions  723 . The structure, function and material of the resin  341 , the electrically conductive particles  342 , and the glue  340 ′ can be referred to the corresponding paragraphs of  FIG.  3 B . 
     Referring to  FIG.  7 C , a light-emitting element  614   b  is provided and the electrodes  614   b - 1 ,  614   b - 2  of the light-emitting element  614   b  are aligned with the electrically conductive regions  723 . The electrodes  614   b - 1 ,  614   b - 2  of the light-emitting element  614   b  may be metal pads, bumps, or any of the bumps of  FIGS.  1 A to  1 C . Referring to  FIG.  7 D , the light-emitting element  614   b  is placed over the electrically conductive regions  723  and the electrically conductive particles  342  are melted to form a connection structure  340 . In this step, the resin  341  in the glue  340 ′ is cured to form the protective portion  343  in the connection structure  340 . The description of the variation of the resin  341 , the electrically conductive particles  342  and the glue  340 ′ in this step can be referred to the corresponding paragraphs of  FIG.  3 C . Then, the function of the abnormal light-emitting element  614   a  is replaced by the light-emitting element  614   b , and the repairing process for the light-emitting module is finished. 
       FIGS.  7 A, and  7 E to  7 G  show the diagrams of a manufacturing process of repairing a light-emitting module in accordance with another embodiment of the present disclosure. After the process disclosed in  FIG.  7 A , the next process is shown in  FIG.  7 E , the glue  440 ′ is formed on and around the electrically conductive regions  723 . The formation, function and material of the glue  440 ′ can be referred to the corresponding paragraphs of  FIG.  4 B . 
     Referring to  FIG.  7 F , a light-emitting element  100 C is provided and the bumps  142   c ,  144   c  of the light-emitting element  100 C are aligned with the electrically conductive regions  723 . The bumps  142   c ,  144   c  of the light-emitting element  100 C can be referred to the corresponding paragraphs of  FIG.  1 C . Referring to  FIG.  7 G , the bumps  142   c ,  144   c  are melted. Therefore, the bumps  142   c ,  144   c  are connected to the electrically conductive regions  723  to form the electrical connection portions  441 ,  442  in the connection structure  440 . In this step, in addition to melting the bumps  142   c ,  144   c , the glue  440 ′ is cured to form the protective portion  443  in the connection structure  440 . Then, the function of the abnormal light-emitting element  614   a  is replaced by the light-emitting element  100 C, and the repairing process for the light-emitting module is finished. 
       FIGS.  8 A to  8 G  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with an embodiment of the present disclosure. Referring to  FIG.  8 A , a transfer device is provided. In an embodiment, the transfer device includes an imprint head  820  and a plurality of pillars  822 . In an embodiment, the plurality of pillars  822  is spaced apart from each other by the same distance. In another embodiment, the plurality of pillars  822  can be spaced apart from each other by a different distance. Besides, adhesive  810 ′ is disposed at each bottom of the plurality of pillars  822 . In an embodiment, the material of the adhesive  810 ′ is a thermal release material. The characteristic of the thermal release material is that the adhesiveness of the material is changed after being heated. In an embodiment, the thermal release material is a thermal release tape that the adhesiveness is reduced after being heated. Reduced adhesiveness means that the adhesive strength after being heated is less than one-twentieth of that before being heated. 
     Referring to  FIG.  8 B , an original substrate  830  is provided and the original substrate  830  includes a plurality of light-emitting elements  860 . The original substrate  830  can be used as a carrier for the light-emitting element  860 . In an embodiment, the material of the original substrate  830  may be plastic, glass or sapphire. In an embodiment, the light-emitting element  860  comprises a semiconductor material. The structure of the plurality of light-emitting elements  860  may be the above-mentioned light-emitting element  100 A, light-emitting element  100 B, light-emitting element  100 C, or a combination thereof, or any suitable light-emitting element. The plurality of light-emitting elements  860  comprises two groups, one group being the selected light-emitting elements  862  and the other group being the unselected light-emitting elements  864 . In an embodiment, the selected light-emitting elements  862  are interspersed with the unselected light-emitting elements  864 . The number of interspersion can be adjusted as needed, for example: 1, 2 or 3. The number of interspersion can be fixed or varied. A plurality of pillars  822  correspond to the selected light-emitting elements  862 . In an embodiment, the adhesive  810 ′ contacts the selected light-emitting elements  862 . 
     Referring to  FIG.  8 C , the selected light-emitting elements  862  are separated from the original substrate  830 . In an embodiment, the bonding force of the adhesive  810 ′ through the plurality of pillars  822  is greater than the bonding force between the selected light-emitting elements  862  and the original substrate  830 , such that the plurality of pillars  822  can grab up the selected light-emitting elements  862 . 
     Referring to  FIG.  8 D , a target substrate  850  is provided. The upper surface of the target substrate  850  has a plurality of conductive pads  852 . A glue (or referred as self-assembly glue)  840 ′ is formed on and around the conductive pads  852 . The selected light-emitting elements  862  on the imprint head  820  are corresponded to the conductive pad  852 . The target substrate  850  can be a circuit substrate. The structure, function and material of the glue (or referred as self-assembly glue)  840 ′ can be referred to the corresponding paragraphs of  FIGS.  3 B and  7 B . 
     Referring to  FIG.  8 E , the selected light-emitting elements  862  are in contact with the glue  840 ′ on the conductive pads  852 . In an embodiment, the light-emitting elements  862  are forced downward such that a contact electrode (not shown) on the light-emitting elements  862  are in contact with or in close proximity to the conductive pads  852 . At this time, a portion of the bottom of the light-emitting element  862  is covered by the glue  840 ′. 
     Referring to  FIG.  8 F , the selected light-emitting elements  862  are placed over the conductive pads  852  and then an energy E 1  is provided to melt the electrically conductive particles (not shown) in the glue  840 ′ and to cure the resin (not shown) in the glue  840 ′ to form a cured glue layer (or referred as connection structure)  840 . The related description of the resin, electrically conductive particles, and glue  840 ′ of this step can be referred to the corresponding paragraphs of  FIG.  3 C . In an embodiment, the energy E 1  is provided by a thermal energy, the electrically conductive particles are melted and the resin is cured by heating, and the adhesiveness of the adhesive  810 ′ is lowered to form the adhesive  810 . As such, the bonding force of the cured adhesive layer (or referred as connection structure)  840  to the light-emitting elements  862  is greater than that to the adhesive  810 . 
     Referring to  FIG.  8 G , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. Since the bonding force of the cured adhesive layer  840  to the light-emitting elements  862  is greater than the bonding force of the adhesive  810  to the light-emitting elements  862  in the previous step, when the imprint head  820  of the transfer device moves upward, the selected light-emitting elements  862  can be fixed on the target substrate  850  and separated from the imprint head  820  of the transfer device. In this step, the light-emitting elements  862  are also electrically connected to the conductive pads  852  of the target substrate  850 . 
       FIGS.  9 A to  9 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. The steps before the  FIG.  9 A  can be referred to the corresponding paragraphs of  FIGS.  8 A to  8 E . In this embodiment, the adhesive  810 ′ is a photodissociation material. The characteristic of a photodissociation material or a photocurable material is that the adhesiveness of the material is changed after being illuminated. In an embodiment, the photodissociation material is a UV release tape that the adhesiveness is reduced after exposure to ultraviolet light. Referring to  FIG.  9 A , the selected light-emitting elements  862  are placed over the conductive pads  852  and provides energy E 1  to melt the electrically conductive particles (not shown) in the glue  840 ′ and to cure the resin in the glue  840 ′. A cured adhesive layer (or referred as connection structure)  840  is formed after the curing. In addition, energy E 2  is provided to the adhesive  810 ′ to convert the adhesive  810 ′ into a lower adhesiveness adhesive  810 . In an embodiment, the energy E 1  is provided by a thermal energy, the energy E 2  is provided by ultraviolet light, and the adhesive  810 ′ is an UV release tape. The description of the variation of the glue  840 ′ at this step can be referred to the corresponding paragraphs of  FIG.  3 C . 
     Referring to  FIG.  9 B , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. This step can be referred to the corresponding paragraphs of  FIG.  8 G . 
       FIGS.  10 A to  10 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. The steps before the  FIG.  10 A  can be referred to the corresponding paragraphs of  FIGS.  8 A to  8 E . In this embodiment, the adhesive  810 ′ is a thermal release material and solder is formed on the conductive pads  852 . In an embodiment, solder having eutectic property is formed on the conductive pads  852 . Referring to  FIG.  10 A , the selected light-emitting elements  862  are placed over the conductive pads  852  and energy E 1  is provided to melt the solder to form the connection structures  1040 . In addition, energy E 3  is simultaneously provided such that the light-emitting elements  862  can be in close contact with the conductive pads  852 . In an embodiment, the energy E 1  is provided by a thermal energy and the energy E 3  is provided by a pressure. 
     Referring to  FIG.  10 B , after the connection structures  1040  are formed under the selected light-emitting elements  862 , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. This step can be referred to the corresponding paragraphs of  FIG.  8 G . 
       FIGS.  11 A to  11 B  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. The steps before the  FIG.  11 A  can be referred to the corresponding paragraphs of  FIGS.  8 A to  8 E . In this embodiment, the adhesive  810 ′ is a thermal release material and the glue  1140 ′ formed on the conductive pads  852  is Anisotropic Conductive Paste (ACP). Referring to  FIG.  11 A , the selected light-emitting elements  862  are placed over the conductive pads  852  and energy E 1  is provided to cure the resin (not shown) in the glue  1140 ′ to form a cured adhesive layer (or referred as connection structure)  1140 . In addition, energy E 3  is simultaneously provided so that the light-emitting element  862  and the conductive pad  852  can be closely adjacent to each other, and the light-emitting element  862  and the conductive pad  852  are electrically connected through the electrically conductive particles in the glue  1140 ′. In an embodiment, the energy E 1  is provided by a thermal energy and the energy E 3  is provided by a pressure. 
     Referring to  FIG.  11 B , after the connection structures  1140  are formed under the selected light-emitting elements  862 , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. This step can be referred to the corresponding paragraphs of  FIG.  8 G . 
       FIG.  12    shows a transfer device  1200  in accordance with an embodiment of the present disclosure. The transfer device  1200  includes an imprint head  1220  and a plurality of pillars  1222 . The structure of the pillar  1222  is viewed from a cross-sectional view. The width of the bottom of the pillar  1222  is greater than the width of the upper portion of the pillar  1222 . A groove is formed between the pillars  1222 , and the width of the groove is gradually narrowed from the side close to the imprint head  1220  to the side far away the imprint head  1220 , so that when a part of the adhesive  1210 ′ is filled into the groove, the grabbing force of the transfer device  1200  to the adhesive  1210 ′ can be increased to avoid the adhesive  1210 ′ falling from the transfer device  1200 . The transfer device  1200  can be used in any of the above-mentioned embodiments in  FIGS.  8 A to  11 B  or any embodiment suitable for transferring light-emitting elements. 
       FIGS.  13 A and  13 B  show the schematic views of the connection structure before and after curing in the light-emitting device in accordance with an embodiment of the present disclosure. Referring to  FIG.  13 A , the upper surface of the target substrate  850  has a plurality of conductive pads  852 . Before curing, a glue (or referred as self-assembly glue)  340 ′ is formed on and around the conductive pads  852 , and the light-emitting elements  862  are formed on the conductive pads  852  and partially embedded in the glue  340 ′. In detail, the glue  340 ′ includes resin  341  and electrically conductive particles  342  dispersed in the resin  341 . A connection region  1301  is above the conductive pad  852  and below the light-emitting element  862 , and non-connection region  1302  is between the conductive pads  852  and between the light-emitting elements  862 . The structure, function and material of the glue  340 ′, the resin  341  and the electrically conductive particles  342  can be referred to the corresponding paragraphs of  FIG.  3 B . 
     Referring to  FIG.  13 B , the connection structure  340  is formed after curing, and the electrically conductive particles  342  are melted and collected in the connection region  1301  and become the electrical connection portion  344 . In addition, after the resin  341  is cured, it becomes the protective portion  343 . In an embodiment, a small portion of the electrically conductive particles  342  are dispersed in the non-connection region  1302 . The electrically conductive particles  342  in the non-connection region  1302  are partially separated from each other so that the problem of short circuit can be avoided. 
       FIGS.  14 A and  14 B  show the schematic views of the connection structure before and after curing in the light-emitting device in accordance with another embodiment of the present disclosure. Referring to  FIG.  14 A , unlike  FIG.  13 A , the resins  341  are respectively formed under and around the two light-emitting elements  862  before curing so the resin  341  are separated from each other. Similarly, the non-connection region  1402  has two regions respectively corresponding to one of the light-emitting elements  862 , and the two regions are separated from each other. The portion of the connection region  1401  is the same with that of  FIG.  13 A . After curing, referring to  FIG.  14 B , the structure, function and material of the connection structure  340 , the protective portion  343 , and the electrical connection portion  344  can be referred to the corresponding paragraphs of  FIG.  13 B . 
       FIGS.  15 A to  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. Referring to  FIG.  15 A , an original substrate  1530  is provided, and a plurality of light-emitting elements  860  are included on the original substrate  1530 . In addition, a target substrate  850  is provided, and the upper surface of the target substrate  850  has a plurality of conductive pads  852 . In an embodiment, the original substrate  1530  includes a carrier  1532  and a releasable glue  1534 . The releasable glue  1534  temporarily fixes the plurality of light-emitting elements  860  on the carrier  1532 . The plurality of light-emitting elements  860  comprise two groups, one group being the selected light-emitting elements  862  and the other group being the unselected light-emitting elements  864 . In an embodiment, each of the selected light-emitting elements  862  includes two contact electrodes  862   a . The structure, function and material of the original substrate  1530 , the light-emitting element  860 , the selected light-emitting element  862 , the unselected light-emitting element  864 , the target substrate  850  and the conductive pad  852  can be referred to the corresponding paragraphs of  FIGS.  8 B and  8 D . 
     Referring to  FIG.  15 B , the glue  340 ′ is respectively formed on and around the conductive pads  852  and the selected light-emitting elements  862  are aligned with the conductive pads  852  having the glue  340 ′. The structure, function and material of the glue  340 ′ can be referred to the corresponding paragraphs of  FIG.  3 B . 
     Referring to  FIG.  15 C , the selected light-emitting elements  862  are placed over the conductive pads  852  and energy E 1  is provided to melt the electrically conductive particles (not shown) in the glue  340 ′ and to cure the resin (not shown) in the glue  340 ′. The description of the energy E 1 , the resin, the electrically conductive particles, and the glue  340 ′ of this step can be referred to the corresponding paragraphs of  FIG.  3 C ,  FIG.  8 F , and  FIGS.  13 A to  14 B . 
     Referring to  FIG.  15 D , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. After the energy E 1  radiates, the adhesiveness of the releasable glue  1534  is lowered, the glue  340 ′ is converted into the connection structure  340 , and the protective portion  343  and the electrical connection portion  344  are formed. The connection force of the connection structure  340  to the selected light-emitting element  862  is greater than the connection force of the releasable glue  1534  to the selected light-emitting element  862 . 
       FIGS.  15 A,  15 B,  15 E, and  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. After the process disclosed in  FIG.  15 B , the next process is shown in  FIG.  15 E . The difference between the process shown in  FIG.  15 E  and the process shown in  FIG.  15 C  is that the position at which the energy E 1  radiates is the original substrate  1530 . After the process disclosed in  FIG.  15 E , the subsequent process is shown in  FIG.  15 D . 
       FIGS.  15 A,  15 B,  15 F, and  15 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. After the process disclosed in  FIG.  15 B , the next process is shown in  FIG.  15 F . The difference between the process shown in  FIG.  15 F  and the process shown in  FIG.  15 C  is that the local areas are provided with the energy E 4 . In an embodiment, the energy E 4  is provided by a laser so that heat can be provided in a local area, such as a connection area. After the process disclosed in  FIG.  15 F , the subsequent process is shown in  FIG.  15 D . 
       FIGS.  16 A to  16 C  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. Referring to  FIG.  16 A , an original substrate  1530  is provided, and a plurality of light-emitting elements  860  is disposed on the original substrate  1530 . In addition, the lower surfaces of the plurality of light-emitting elements  860  are covered by the glue  340 ′. Furthermore, a target substrate  850  is provided, and the upper surface of the target substrate  850  has a plurality of conductive pads  852 . The structure, function, and material of the original substrate  1530 , the light-emitting element  860 , the target substrate  850 , and the conductive pad  852  can be referred to the corresponding paragraphs of  FIGS.  8 B,  8 D, and  15 A . 
     Referring to  FIG.  16 B , the selected light-emitting elements  862  are placed on the conductive pads  852  and then an energy E 1  is provided to melt the electrically conductive particles (not shown) in the glue  340 ′ and to cure the resin (not shown) in the glue  340 ′. The related descriptions of the energy E 1 , the resin, the electrically conductive particles, and the glue  340 ′ of this step can be referred to the corresponding paragraphs of  FIG.  3 C ,  FIG.  8 F , and  FIGS.  13 A to  14 B . 
     Referring to  FIG.  16 C , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. The related descriptions of this step can be referred to the corresponding paragraphs of  FIG.  15 D . 
       FIGS.  16 D,  16 E, and  16 C  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. Referring to  FIG.  16 D , an original substrate  1530  is provided and a plurality of light-emitting elements  860  is disposed on the original substrate  1530 . The lower surfaces of the plurality of light-emitting elements  860  are covered by the glue  340 ′. Furthermore, a target substrate  850  is provided and a plurality of conductive pads  852  is formed on the upper surface of the target substrate. The structure, function, and material of the original substrate  1530 , the light-emitting element  860 , the target substrate  850 , and the conductive pad  852  can be referred to the corresponding paragraphs of  FIGS.  8 B,  8 D, and  15 A . 
     Referring to  FIG.  16 E , energy E 4  is provided in a local area to melt the electrically conductive particles (not shown) in the glue  340 ′ and to cure the resin (not shown) in the glue  340 ′. In an embodiment, the energy E 4  can be provided by a laser. The descriptions of the energy E 4 , the resin, the electrically conductive particle, and the glue  340 ′ of this step can be referred to the corresponding paragraphs of  FIGS.  3 C,  8 F,  13 A to  14 B, and  15 F . After the process shown in  FIG.  16 E  is performed, the subsequent process is shown in  FIG.  16 C . 
       FIG.  17 A  shows a bottom view of a light-emitting element in accordance with an embodiment of the present disclosure.  FIG.  17 B  shows a bottom view of a light-emitting element covering the connection structure in accordance with an embodiment of the present disclosure.  FIG.  17 C  shows a bottom view of a target substrate on which the connection structure is formed in accordance with an embodiment of the present disclosure.  FIGS.  17 A to  17 C  can be referred to the relationships between the light-emitting element, the connection structure, and the target substrate in any of the embodiments disclosed in the present disclosure. 
     Referring to  FIG.  17 A , a bottom view of the selected light-emitting element  862  includes two contact electrodes  862   a  and a boundary  862   b . The area enclosed by the boundary  862   b  is A3. 
     Referring to  FIG.  17 B , the connection structure  340  covers a portion of the bottom surface of the selected light-emitting element  862 . In addition, the area of the selected light-emitting element  862  covered by the connection structure  340  is A4. In an embodiment, the ratio of area A4 to area A3 is between 60% to 80%. If the ratio of the area A4 to the area A3 is greater than 80%, while the connection structure  340  is in uncured state, the connection structure (glue)  340  may stick to the adjacent unselected light-emitting element  864  and cause the unselected light-emitting element  864  be transferred to the target substrate during the transferring process disclosed in aforementioned embodiments. 
     Referring to  FIG.  17 C , the connection structure  340  covers a portion of the bottom surface of the conductive pad  852 . The area that the connection structure  340  covers the selected conductive pad  852  is A5. In an embodiment, the ratio of area A5 to area A3 is between 60% to 80%. If the ratio of the area A5 to the area A3 is greater than 80%, while the connection structure  340  is in uncured state, the connection structure (glue)  340  may stick to the adjacent unselected light-emitting element  864  and cause the unselected light-emitting element  864  be transferred to the target substrate during the transferring process disclosed in aforementioned embodiments. 
       FIGS.  18 A to  18 D  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. Referring to  FIG.  18 A , the difference from  FIG.  15 A  is that interval pieces  1811  and  1812  exist between the original substrate  1530  and the target substrate  850 . In an embodiment, the interval pieces  1811 ,  1812  are on the target substrate  850  and at the edge of the target substrate  850 , for example, four corners. In another embodiment, the interval pieces  1811 ,  1812  can be in other areas on the target substrate  850 , for example, an intermediate area. In an embodiment, the interval pieces  1811 ,  1812  are in the shape of sphere. In other embodiments, the interval pieces  1811 ,  1812  may be in the shape of pillar, cuboid or cone. The number of interval pieces  1811 ,  1812  can be adjusted as needed. The description of other features in  FIG.  18 A  can be referred to the corresponding paragraphs of  FIG.  15 A . 
     Referring to  FIG.  18 B , the glues  1840 ′- 1  are respectively formed on and around the conductive pads  852  and the selected light-emitting elements  862  are aligned with the conductive pads  852  having the glue  1840 ′- 1 . For the structure, function and material of the glue  1840 ′- 1  can be referred to the corresponding paragraphs of  FIG.  3 B . 
     Referring to  FIG.  18 C , the selected light-emitting elements  862  are placed over the conductive pad  852  and an energy E 1  is provided to melt the electrically conductive particles (not shown) in the glue  1840 ′- 1  and to cure the resin (not shown) in the glue  1840 ′- 1 . The interval between the original substrate  1530  and the target substrate  850  is limited by the diameter R of the interval pieces  1811 ,  1812 . Therefore, the introduction of the interval pieces  1811 ,  1812  can provide a more uniform interval between the original substrate  1530  and the target substrate  850 . In other words, the thickness Y of the selected light-emitting element  862  is fixed, therefore the distance h between the light-emitting element  862  and the target substrate  850  can be fixed because R=Y+h. The related description of the energy E 1 , the resin, the electrically conductive particles, and the glue  1840 ′- 1  of this step can be referred to the corresponding paragraphs of  FIG.  3 C ,  FIG.  8 F , and  FIGS.  13 A to  14 B . 
     Referring to  FIG.  18 D , the selected light-emitting elements  862  are formed on the target substrate  850  and separated from the transfer device. The related description of this step can be referred to the corresponding paragraphs of  FIG.  15 D . 
       FIGS.  18 A,  18 B,  18 E to  18 F  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure.  FIG.  18 E  is followed after  FIG.  18 B ,  FIG.  18 E  is similar to  FIG.  18 C , and  FIG.  18 F  is similar to  FIG.  18 D . Referring to  FIG.  18 E , in an embodiment, the glue  1840 ′- 2  is formed on and around the conductive pad  852 , and the width of the glue  1840 ′- 2  is greater than the width W of the light-emitting element  860  and smaller than the width W of the light-emitting element  860  plus the distance d between the light-emitting elements  860 . Referring to  FIG.  18 F , after melting the electrically conductive particles (not shown) in the glue  1840 ′- 2  and curing the resin (not shown) in the glue  1840 ′- 2 , the width of the connection structure  1840 - 2  is smaller than the width W of the light-emitting element  860  plus the distance d between the light-emitting elements  860 . Therefore it can avoid the connection structure (glue)  1840 - 2  may stick to the adjacent unselected light-emitting element  864  in the uncured state and cause the unselected light-emitting element  864  be transferred to the target substrate during the transferring process disclosed in aforementioned embodiments. 
       FIGS.  18 A,  18 G to  18 I  show the diagrams of a manufacturing process of transferring a plurality of light-emitting elements to a target substrate in accordance with another embodiment of the present disclosure. The process shown in  FIG.  18 G  is followed after the process disclosed in  FIG.  18 A . Referring to  FIG.  18 G , the difference between  FIG.  18 G  and  FIG.  18 B  is that the glue  1840 ′- 3  is first formed on the selected light-emitting element  862 . After that, the process shown in  FIG.  18 H  is similar to the process shown in  FIG.  18 C , and the process shown in  FIG.  18 F  is similar to the process shown in  FIG.  18 D . 
       FIGS.  19 A to  19 B  show the schematic views of the connection structure before and after curing in the light-emitting device disclosed in  FIGS.  18 A to  18 D .  FIG.  19 A  shows that glue (or referred as self-assembly glue)  1840 ′- 1  is formed on and around the conductive pad  852  before curing (low temperature), and the bottom surface portion of the light-emitting element  862  is embedded in the glue  1840 ′- 1 . Since no downward pressing force is provided, the glue  1840 ′- 1  only covers the bottom surface of the light-emitting element  862  and does not cover the side surface of the light-emitting element  862 . Besides, the electrically conductive particles  1842 - 1  are substantially uniformly dispersed in the resin  1841 - 1 . A connection region  1901  is above the conductive pad  852  and below the light-emitting element  862 , and non-connection region  1902  is between the conductive pads  852  and between the light-emitting elements  862 . The density of the electrically conductive particles  1842 - 1  in the connection region  1901  and the non-connection region  1902  are substantially the same. 
       FIG.  19 B  shows that the glue  1840 ′- 1  forms a connection structure  1840 - 1  after curing (at a high temperature). Similarly, the connection structure  1840 - 1  only covers the bottom surface of the light-emitting element  862  and does not cover the side surface of the light-emitting element  862 . However, the density of the electrically conductive particles  1842 - 1  in the connection region  1901  is greater than the density in the non-connection region  1902 . 
       FIG.  19 C  shows a top view of a light-emitting device disclosed in  FIG.  18 D . In an embodiment, the area A(P) of the connection structure  1840 - 1  is smaller than the area A(C) of the light-emitting element  862  on the target substrate  850 . In an embodiment, the area A(S) of the electrical connection portion  1844 - 1  is larger than the area A(E) of the contact electrode  862   a.    
       FIG.  19 D  shows a top view of a light-emitting device disclosed in  FIG.  18 F . In an embodiment, the area A(P) of the connection structure  1840 - 2  is larger than the area A(C) of the light-emitting element  862  on the target substrate  850 . 
     The embodiments described above are merely illustrative of the technical spirit and the features of the present disclosure, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present disclosure cannot be limited thereto. That is, the equivalent changes or modifications made by the spirit of the present disclosure should still be covered by the patent of the present disclosure.