Light emitting diode for facilitating laser welding and method of manufacturing the same

Abstract

The present disclosure provides a laser-welding-facilitating light-emitting diode and a preparation method thereof, and belongs to the technical field of optoelectronic manufacturing. The light-emitting diode comprises a substrate, a light-emitting structure, a light-transmitting insulating layer, and a welding spot. The light-emitting structure and the light-transmitting insulating layer are both located on a bearing surface of the substrate, the light-transmitting insulating layer is located on a side of the light-emitting structure and connected with a side wall of the light-emitting structure, and the welding spot is located on a surface of the light-transmitting insulating layer away from the substrate and electrically connected with the light-emitting structure. A projection of the welding spot on the bearing surface of the substrate is at least partially located outside a projection of the light-emitting structure on the bearing surface of the substrate. Since the projection of the welding spot on the bearing surface of the substrate is at least partially located outside the projection of the light-emitting structure on the bearing surface of the substrate, when laser welding is adopted, a laser beam can irradiate the welding spot from the back surface of the substrate through the light-transmitting insulating layer, so that damage of the light-emitting structure caused by the laser beam can be avoided, and problems such as current leakage of the light-emitting diode can be avoided.

Description

Technical Field

[0001] This disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light-emitting diode that is conducive to laser welding and a method for its fabrication. Background Technology

[0002] Light-emitting diodes (LEDs) are highly influential new products in the optoelectronics industry. They are characterized by their small size, long lifespan, rich and colorful colors, and low energy consumption, and are widely used in display devices.

[0003] Light-emitting diodes (LEDs) are typically soldered using solder joints, and laser soldering is a common method. For smaller LEDs, such as miniature LEDs, laser soldering is usually performed from the back of the LED (the side furthest from the solder joint). During the soldering process, the laser beam passes through the light-emitting structure and illuminates the solder joint.

[0004] Because laser energy is very high, it may damage the light-emitting structure during the process of the laser penetrating the light-emitting structure, leading to problems such as leakage current in the light-emitting diode. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) that is advantageous for laser welding and its fabrication method, which can prevent the LED from being damaged by the laser during the laser welding process. The technical solution is as follows:

[0006] On one hand, embodiments of this disclosure provide a light-emitting diode, which includes a substrate, a light-emitting structure, a light-transmitting insulating layer, and solder joints;

[0007] Both the light-emitting structure and the light-transmitting insulating layer are located on the bearing surface of the substrate. The light-transmitting insulating layer is located to the side of the light-emitting structure and is connected to the sidewall of the light-emitting structure. The solder joint is located on the surface of the light-transmitting insulating layer away from the substrate and is electrically connected to the light-emitting structure.

[0008] The orthographic projection of the solder joint onto the substrate's bearing surface is at least partially located outside the orthographic projection of the light-emitting structure onto the substrate's bearing surface.

[0009] Optionally, the light-emitting structure includes an epitaxial structure and a reflective structure, wherein the reflective structure is located on the sidewall of the epitaxial structure.

[0010] Optionally, the reflective structure includes a first insulating layer, a metal reflective layer, and a first reflective mirror layer sequentially stacked on the sidewall of the epitaxial structure.

[0011] Optionally, the sidewall of the light-transmitting insulating layer away from the light-emitting structure is roughened.

[0012] Optionally, the roughened surface is covered with a silicon oxide layer.

[0013] On the other hand, this disclosure also provides a method for fabricating a light-emitting diode, the method comprising:

[0014] A light-emitting structure and a light-transmitting insulating layer are formed on the substrate bearing surface. The light-transmitting insulating layer is located on the side of the light-emitting structure and is connected to the sidewall of the light-emitting structure.

[0015] A solder joint is formed on the surface of the light-transmitting insulating layer away from the substrate. The solder joint is electrically connected to the light-emitting structure, and the orthographic projection of the solder joint on the bearing surface of the substrate is at least partially located outside the orthographic projection of the light-emitting structure on the bearing surface of the substrate.

[0016] Optionally, forming the light-emitting structure and the light-transmitting insulating layer on the substrate's bearing surface includes:

[0017] An epitaxial structure is formed on the growth substrate;

[0018] The epitaxial structure is transferred to the bearing surface of the substrate, and the growth substrate is removed;

[0019] A reflective structure is formed on the sidewall of the epitaxial structure to obtain the light-emitting structure;

[0020] The light-transmitting insulating layer is formed on the sidewall of the reflective structure.

[0021] Optionally, the reflective structure is formed on the sidewall of the epitaxial structure, comprising:

[0022] A first insulating layer is formed on the sidewall of the epitaxial structure;

[0023] A metallic reflective layer is formed on the side of the first insulating layer away from the epitaxial structure;

[0024] A first reflective mirror layer is formed on the side of the metal reflective layer away from the first insulating layer to form the reflective structure.

[0025] Optionally, after forming the light-transmitting insulating layer on the sidewall of the reflective structure, the method further includes:

[0026] The sidewall of the light-transmitting insulating layer away from the light-emitting structure is roughened to form a roughened surface.

[0027] Optionally, after roughening the sidewall of the light-transmitting insulating layer away from the light-emitting structure, the method further includes:

[0028] A silicon oxide layer is formed on the roughened surface.

[0029] The beneficial effects of the technical solutions provided in this disclosure include at least the following:

[0030] By setting a light-transmitting insulating layer on the substrate bearing surface, the light-transmitting insulating layer is located on the side of the light-emitting structure and connected to the side wall of the light-emitting structure. The solder joint is set on the light-transmitting insulating layer. Since the orthogonal projection of the solder joint on the substrate bearing surface is at least partially outside the orthogonal projection of the light-emitting structure on the substrate bearing surface, when using laser welding, the laser beam can pass through the light-transmitting insulating layer from the back of the substrate to irradiate the solder joint, avoiding damage to the light-emitting structure by the laser beam, thereby avoiding problems such as leakage of the light-emitting diode. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0033] Figure 2 This is a top view of a light-emitting diode provided in an embodiment of this disclosure;

[0034] Figure 3 This is a schematic diagram of a laser welding method provided in an embodiment of this disclosure;

[0035] Figure 4 This is a flowchart of a method for fabricating a light-emitting diode according to an embodiment of this disclosure;

[0036] Figure 5 This is a flowchart of a method for fabricating a light-emitting diode according to an embodiment of this disclosure;

[0037] Figure 6 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0038] Figure 7 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0039] Figure 8 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0040] Figure 9 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0041] Figure 10This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0042] Figure 11 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure;

[0043] Figure 12 This is a schematic diagram of the fabrication process of a light-emitting diode provided in an embodiment of this disclosure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. For example... Figure 1 As shown, the light-emitting diode includes a substrate 10, a light-emitting structure 20, a light-transmitting insulating layer 30, and solder joints 40.

[0046] Both the light-emitting structure 20 and the light-transmitting insulating layer 30 are located on the bearing surface of the substrate 10. The light-transmitting insulating layer 30 is located to the side of the light-emitting structure 20 and is connected to the sidewall of the light-emitting structure 20. The solder joint 40 is located on the surface of the light-transmitting insulating layer 30 away from the substrate 10 and is electrically connected to the light-emitting structure 20.

[0047] Figure 2 This is a top view of a light-emitting diode provided in an embodiment of this disclosure. Figure 1 and Figure 2 As shown, the orthographic projection of the solder joint 40 onto the bearing surface of the substrate 10 is at least partially located outside the orthographic projection of the light-emitting structure 20 onto the bearing surface of the substrate 10.

[0048] Figure 3 This is a schematic diagram of a laser welding method provided in an embodiment of this disclosure. (As shown...) Figure 3 As shown, by providing a light-transmitting insulating layer 30 on the bearing surface of the substrate 10, the light-transmitting insulating layer 30 is located on the side of the light-emitting structure 20 and connected to the side wall of the light-emitting structure 20. The solder joint 40 is provided on the light-transmitting insulating layer 30. Since the orthographic projection of the solder joint 40 on the bearing surface of the substrate 10 is at least partially located outside the orthographic projection of the light-emitting structure 20 on the bearing surface of the substrate 10, when using laser welding, the laser beam can pass through the light-transmitting insulating layer 30 from the back of the substrate 10 to irradiate the solder joint 40, avoiding damage to the light-emitting structure 20 by the laser beam, thereby avoiding problems such as leakage of the light-emitting diode.

[0049] like Figure 3As shown, the light-emitting structure 20 includes an epitaxial structure 21 and an electrode 23. The epitaxial structure 21 may include an N-type layer 211, a multiple quantum well layer 212, and a P-type layer 213 sequentially stacked on the substrate 10. The side of the epitaxial structure 21 away from the substrate 10 has a groove exposing the N-type layer 211.

[0050] As an example, the light-emitting diode can be a red light-emitting diode. The N-type layer 211, the multiple quantum well layer 212, and the P-type layer 213 can all be AlInP-based semiconductor layers. For example, the N-type layer 211 is an N-type AlInP carrier confinement layer, the P-type layer 213 is a P-type AlInP carrier confinement layer, and the multiple quantum well layer 212 is an AlGaInP multiple quantum well layer, wherein the Al content of each layer can be different.

[0051] In addition, in some examples, the epitaxial structure 21 of the light-emitting diode may also include an N-type AlGaInP current spreading layer, a GaP window layer, and other structures. The thickness of each layer can be set according to specific needs. For example, the thickness of the GaP window layer can be set to 3 micrometers.

[0052] Electrode 23 includes a first electrode 231 and a second electrode 232. The first electrode 231 is a P electrode, located on the P-type layer 213 and electrically connected to the P-type layer 213. The second electrode 232 is an N electrode, located in the groove and electrically connected to the N-type layer 211.

[0053] Solder joint 40 may include a first solder joint 41 and a second solder joint 42. The first solder joint 41 is electrically connected to the first electrode 231, and the second solder joint 42 is electrically connected to the second electrode 232.

[0054] Solder joint 40 can be a multilayer structure. For example, solder joint 40 includes a Ti layer, an Al layer, a Ti layer, a Ni layer, and an Au layer stacked sequentially. The thickness of each layer can be from 100 nm to 8000 nm. For example, the thicknesses of the Ti layer, Al layer, Ti layer, Ni layer, and Au layer can be 200 nm, 5000 nm, 200 nm, 3000 nm, and 6000 nm, respectively.

[0055] like Figure 3 As shown, the light-emitting structure 20 also includes a reflective structure 22, which is located on the sidewall of the epitaxial structure 21.

[0056] As an example, Figure 3 In this structure, the reflective structure 22 is located on the sidewall of the N-type layer 211, the multi-quantum well layer 212, and the P-type layer 213 on the same side, so as to minimize the influence of the laser on the multi-quantum well layer 212.

[0057] In other examples, the reflective structure 22 may also be located on the sidewall of the N-type layer 211 near the second electrode 232.

[0058] The reflective structure 22 located on the sidewall of the epitaxial structure 21 can reflect the laser beam. When laser welding is used, the part of the laser beam that changes its propagation direction due to reflection, refraction and other reasons can be reflected by the reflective structure 22, which further prevents the laser beam from entering the epitaxial structure 21 and prevents the epitaxial structure 21 from being damaged.

[0059] like Figure 3 As shown, the reflective structure 22 includes a first insulating layer 221, a metal reflective layer 222, and a first reflective mirror layer 223, which are sequentially stacked on the sidewall of the epitaxial structure 21.

[0060] The first insulating layer 221 separates the metal reflective layer 222 from the epitaxial structure 21, serving as an insulating layer. The metal reflective layer 222 is made of a metal with high reflectivity, which can effectively reflect laser light. The first reflective mirror layer 223 can also reflect light, preventing laser light from entering the epitaxial structure 21.

[0061] For example, the first insulating layer 221 may be a silicon oxide layer. As an example, the thickness of the first insulating layer 221 may be 500 angstroms to 10000 angstroms. For instance, the thickness of the first insulating layer 221 may be 5000 angstroms.

[0062] The metallic reflective layer 222 can be a chromium metal layer. As an example, the thickness of the metallic reflective layer 222 can be 50 angstroms to 1000 angstroms. For example, the thickness of the metallic reflective layer 222 can be 500 angstroms.

[0063] The first reflector layer 223 can be a distributed Bragg reflector. A distributed Bragg reflector is a periodic structure consisting of alternating layers of two materials with different refractive indices. As an example, the number of periods in a distributed Bragg reflector can range from 2 to 10. For instance, a distributed Bragg reflector may have 5 periods.

[0064] In the first reflective mirror layer 223, the thickness of each layer can be set according to the wavelength of the laser used during laser welding. For example, if a laser with a wavelength of 1024nm is used for welding, the thickness of each layer can be 200nm to 300nm, such as 256nm.

[0065] Optionally, the light-transmitting insulating layer 30 can be made of inorganic insulating materials, such as silicon oxide or silicon nitride, which have good light transmittance, in order to reduce the absorption of laser light and avoid affecting the welding process.

[0066] In some examples, the sidewall of the light-transmitting insulating layer 30 away from the light-emitting structure 20 is roughened.

[0067] After the sidewalls of the light-transmitting insulating layer 30 are roughened, they can absorb light, thereby preventing laser from escaping from the sidewalls of the light-transmitting insulating layer 30.

[0068] like Figure 3 As shown, a silicon oxide layer 31 is also covered on the roughened surface of the light-transmitting insulating layer 30. The sidewalls of the light-transmitting insulating layer 30 are roughened and uneven, which makes the surface of the formed silicon oxide layer 31 also uneven, enabling it to absorb laser light and reduce laser transmission.

[0069] The light-emitting diode may also include a second reflector layer 50, which may be a distributed Bragg reflector. The second reflector layer 50 is located on the surface of the light-emitting structure 20 away from the substrate 10.

[0070] The surface of the second reflective mirror layer 50 away from the substrate 10 and the surface of the light-transmitting insulating layer 30 away from the substrate 10 can be coplanar. The second reflective mirror layer 50 and the light-transmitting insulating layer 30 can be connected. The first solder joint 41 is connected to the first electrode 231 through a via on the second reflective mirror layer 50 or the light-transmitting insulating layer 30, and the second solder joint 42 is connected to the second electrode 232 through a via on the second reflective mirror layer 50 or the light-transmitting insulating layer 30.

[0071] The second reflective mirror layer 50 can reflect the light emitted by the light-emitting diode, allowing more light to escape from the substrate 10 and improving the brightness of the light-emitting diode.

[0072] The light-emitting diode may also include a passivation layer 60, which at least covers the surface of the light-transmitting insulating layer 30 and the second reflective layer 50. The first solder joint 41 and the second solder joint 42 are at least partially exposed outside the passivation layer 60 so that they can be soldered.

[0073] Figure 4 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. This method is used to manufacture... Figures 1-3 The light-emitting diode shown. For example... Figure 4 As shown, the preparation method includes:

[0074] S11: A light-emitting structure 20 and a light-transmitting insulating layer 30 are formed on the bearing surface of the substrate 10.

[0075] The light-transmitting insulating layer 30 is located on the side of the light-emitting structure 20 and is connected to the side wall of the light-emitting structure 20.

[0076] S12: Solder joints 40 are formed on the surface of the light-transmitting insulating layer 30 away from the substrate 10.

[0077] The solder joint 40 is electrically connected to the light-emitting structure 20, and the orthographic projection of the solder joint 40 on the bearing surface of the substrate 10 is at least partially located outside the orthographic projection of the light-emitting structure 20 on the bearing surface of the substrate 10.

[0078] By providing a light-transmitting insulating layer 30 on the bearing surface of the substrate 10, the light-transmitting insulating layer 30 is located on the side of the light-emitting structure 20 and connected to the side wall of the light-emitting structure 20. The solder joint 40 is provided on the light-transmitting insulating layer 30. Since the orthographic projection of the solder joint 40 on the bearing surface of the substrate 10 is at least partially located outside the orthographic projection of the light-emitting structure 20 on the bearing surface of the substrate 10, when using laser welding, the laser beam can pass through the light-transmitting insulating layer 30 from the back of the substrate 10 to irradiate the solder joint 40, avoiding damage to the light-emitting structure 20 by the laser beam, thereby avoiding problems such as leakage of the light-emitting diode.

[0079] Figure 5 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. This method is used to manufacture... Figures 1-3 The light-emitting diode shown below. (The following is in conjunction with...) Figures 6-12 right Figure 5 The provided preparation method is described in detail, such as... Figure 5 As shown, the preparation method includes:

[0080] S21: Provide a growth substrate 11.

[0081] For example, the growth substrate 11 can be a GaAs substrate.

[0082] S22: An epitaxial structure 21 is formed on the growth substrate 11.

[0083] For example, such as Figure 6 As shown, the epitaxial structure 21 includes an N-type layer 211, a multi-quantum-well layer 212, and a P-type layer 213.

[0084] An epitaxial structure 21 is formed by epitaxial growth on the growth substrate 11. During the epitaxial growth, an etching stop layer, an N-type AlGaInP current spreading layer, an N-type AlInP carrier confinement layer, an AlGaInP multiple quantum well layer, a P-type AlInP carrier confinement layer, and a GaP window layer are formed on the growth substrate 11.

[0085] The epitaxial structure 21 will vary for different light-emitting diodes; the above structure will be used as an example for explanation only.

[0086] In specific implementation, embodiments of this disclosure may use high-purity H2 and / or N2 as carrier gas, NH3 as N source, TEGa or TMGa as Ga source, TMIn as In source, SiH4 as n-type dopant, and TMAl as aluminum source.

[0087] S23: Transfer the epitaxial structure 21 to the bearing surface of the substrate 10 and remove the growth substrate 11.

[0088] like Figure 7 As shown, the epitaxial structure 21 is transferred to the substrate 10.

[0089] The substrate 10 can be a transparent substrate, such as a sapphire substrate. Sapphire substrates have high light transmittance and are hard and chemically stable.

[0090] During the transfer process, the GaP window layer can be roughened before forming a bonding layer. For example, the bonding layer can be a silicon oxide layer. The thickness of the bonding layer can be 2 micrometers. After forming the bonding layer, it can also be polished.

[0091] When transferring the epitaxial structure 21 to the bearing surface of the substrate 10, a suitable temperature is selected for bonding, for example, the bonding temperature can be 300℃. When removing the growth substrate 11, it can be removed by solution etching. After removing the growth substrate 11, the epitaxial structure 21 and the substrate 10 can be bonded again.

[0092] S24: An electrode 23 is formed on the epitaxial structure 21.

[0093] like Figure 8 As shown, electrode 23 includes a first electrode 231 and a second electrode 232, wherein the first electrode 231 is a P electrode and the second electrode 232 is an N electrode.

[0094] The epitaxial structure 21 has a groove formed on the side away from the substrate 10 by etching, exposing the N-type layer 211. The first electrode 231 is located on the P-type layer 213 and is electrically connected to the P-type layer 213, and the second electrode 232 is located in the groove and is electrically connected to the N-type layer 211.

[0095] The first electrode 231 can be made of metal gold or beryllium by vapor deposition. After the first electrode 231 is formed, it can be annealed.

[0096] The second electrode 232 can be made of metal gold or germanium by vapor deposition. After the second electrode 232 is formed, it can be annealed.

[0097] During electrode deposition, the evaporation power and time are controlled to avoid excessive alloy composition; for example, the evaporation time is less than or equal to 5 seconds.

[0098] S25: A reflective structure 22 is formed on the sidewall of the extensional structure 21.

[0099] like Figure 9 As shown, in some examples, the reflective structure 22 can be formed in the following manner.

[0100] A first insulating layer 221 is formed on the sidewall of the epitaxial structure 21.

[0101] A metal reflective layer 222 is formed on the side of the first insulating layer 221 away from the epitaxial structure 21.

[0102] A first reflective mirror layer 223 is formed on the side of the metal reflective layer 222 away from the first insulating layer 221 to form a reflective structure 22.

[0103] The first insulating layer 221 separates the metal reflective layer 222 from the epitaxial structure 21, serving as an insulating layer. The metal reflective layer 222 is made of a metal with high reflectivity, which can effectively reflect laser light. The first reflective mirror layer 223 also serves to reflect light, preventing laser light from entering the epitaxial structure 21.

[0104] For example, the first insulating layer 221 may be a silicon oxide layer. As an example, the thickness of the first insulating layer 221 may be 500 angstroms to 10000 angstroms. For instance, the thickness of the first insulating layer 221 may be 5000 angstroms.

[0105] The metallic reflective layer 222 can be a chromium metal layer. As an example, the thickness of the metallic reflective layer 222 can be 50 angstroms to 1000 angstroms. For example, the thickness of the metallic reflective layer 222 can be 500 angstroms.

[0106] The first reflector layer 223 can be a distributed Bragg reflector. A distributed Bragg reflector is a periodic structure consisting of alternating layers of two materials with different refractive indices. As an example, the number of periods in a distributed Bragg reflector can range from 2 to 10. For instance, a distributed Bragg reflector may have 5 periods.

[0107] S26: A light-transmitting insulating layer 30 is formed on the sidewall of the reflective structure 22.

[0108] Optionally, the light-transmitting insulating layer 30 can be formed by deposition of inorganic insulating materials, such as silicon oxide, silicon nitride, etc. Inorganic insulating materials with good light transmittance are used to reduce the absorption of laser light and avoid affecting the welding process.

[0109] like Figure 10 As shown, in step S26, a second reflective mirror layer 50 may also be formed on the surface of the light-emitting structure 20 away from the substrate 10. The second reflective mirror layer 50 may also be a distributed Bragg reflector.

[0110] The light-transmitting insulating layer 30 can be fabricated before or after the second reflective mirror layer 50.

[0111] S27: Roughen the sidewall of the light-transmitting insulating layer 30 away from the light-emitting structure 20 to form a roughened surface.

[0112] Specifically, a roughened surface can be formed by treating the sidewall of the light-transmitting insulating layer 30 away from the light-emitting structure 20 with a roughening liquid. The roughened surface can absorb light, thereby preventing the laser from escaping from the sidewall of the light-transmitting insulating layer 30.

[0113] S28: A silicon oxide layer 31 is formed on the roughened surface.

[0114] like Figure 11 As shown, a silicon oxide layer 31 is formed on the roughened surface.

[0115] The silicon oxide layer 31 can be formed on the roughened surface by deposition. The sidewalls of the light-transmitting insulating layer 30 are roughened and uneven, so that the surface of the formed silicon oxide layer 31 is also uneven, which can absorb the laser and reduce the transmission of the laser.

[0116] S29: Solder joints 40 are formed on the surface of the light-transmitting insulating layer 30 away from the substrate 10.

[0117] like Figure 12 As shown, several vias can be formed on the light-transmitting insulating layer 30 or the second reflective mirror layer 50. The vias are connected to the first electrode 231 or the second electrode 232, and then solder joints 40 are formed on the light-transmitting insulating layer 30. Solder joints 40 include a first solder joint 41 and a second solder joint 42. The first solder joint 41 is electrically connected to the first electrode 231 through the via, and the second solder joint 42 is electrically connected to the second electrode 232 through the via.

[0118] Solder joint 40 can be formed by vapor deposition. Solder joint 40 can be a multilayer structure, for example, including a Ti layer, an Al layer, a Ti layer, a Ni layer, and an Au layer stacked sequentially. The thickness of each layer can be from 100nm to 8000nm, for example, the thicknesses of the Ti layer, Al layer, Ti layer, Ni layer, and Au layer can be 200nm, 5000nm, 200nm, 3000nm, and 6000nm, respectively.

[0119] The orthographic projections of the first solder joint 41 and the second solder joint 42 onto the bearing surface of the substrate 10 are at least partially located outside the orthographic projection of the light-emitting structure 20 onto the bearing surface of the substrate 10.

[0120] S30: Formation of passivation layer 60.

[0121] The structure after the passivation layer 60 is formed can be referred to Figure 1 or Figure 3 As shown. The passivation layer 60 covers at least the surfaces of the light-transmitting insulating layer 30 and the second reflective mirror layer 50. The passivation layer 60 has through holes exposing the first solder joint 41 and the second solder joint 42.

[0122] After the passivation layer 60 is formed, the substrate 10 can be thinned, for example, to 80 micrometers.

[0123] After thinning, processes such as cutting, dicing, and dicing can be performed to obtain multiple light-emitting diodes (LEDs). During cutting, for example, a 1024nm laser can be used for stealth cutting to reduce the impact of photon degeneracy on the material. Using stealth cutting for dicing can also reduce the impact on the brightness of the LEDs.

[0124] The obtained light-emitting diodes can also be tested, such as photoelectric testing, to obtain photoelectric parameters.

[0125] After passing the test, the obtained LEDs can be soldered to circuit boards or other applications. Laser soldering can be used. For example, the laser beam length and width are 50 micrometers and 20 micrometers, respectively. A smaller beam area results in more concentrated energy and also helps to further prevent the laser beam from entering the light-emitting structure and causing adverse effects.

[0126] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light emitting diode, characterized by, It includes a substrate (10), a light-emitting structure (20), a light-transmitting insulating layer (30), and solder joints (40); The light-emitting structure (20) and the light-transmitting insulating layer (30) are both located on the bearing surface of the substrate (10). The light-transmitting insulating layer (30) is located on the side of the light-emitting structure (20) and is connected to the sidewall of the light-emitting structure (20). The solder joint (40) is located on the surface of the light-transmitting insulating layer (30) away from the substrate (10) and is electrically connected to the light-emitting structure (20). The light-transmitting insulating layer (30) is used to allow the laser beam to pass through from the back of the substrate (10) and irradiate the solder joint (40). The solder joint (40) is at least partially located outside the orthogonal projection of the light-emitting structure (20) onto the bearing surface of the substrate (10).

2. The light emitting diode of claim 1, wherein, The light-emitting structure (20) includes an epitaxial structure (21) and a reflective structure (22), wherein the reflective structure (22) is located on the sidewall of the epitaxial structure (21).

3. The light emitting diode of claim 2, wherein, The reflective structure (22) includes a first insulating layer (221), a metal reflective layer (222), and a first reflective mirror layer (223) that are sequentially stacked on the sidewall of the epitaxial structure (21).

4. The light emitting diode of claim 1, wherein, The sidewall of the light-transmitting insulating layer (30) away from the light-emitting structure (20) is roughened.

5. The light emitting diode of claim 4, wherein, The roughened surface is covered with a silicon oxide layer (31).

6. A method for fabricating a light-emitting diode, characterized in that, The method includes: A light-emitting structure (20) and a light-transmitting insulating layer (30) are formed on the bearing surface of the substrate (10). The light-transmitting insulating layer (30) is located on the side of the light-emitting structure (20) and is connected to the sidewall of the light-emitting structure (20). A solder joint (40) is formed on the surface of the light-transmitting insulating layer (30) away from the substrate (10). The light-transmitting insulating layer (30) is used to allow a laser beam to pass through from the back of the substrate (10) and irradiate the solder joint (40). The solder joint (40) is electrically connected to the light-emitting structure (20), and the orthographic projection of the solder joint (40) on the bearing surface of the substrate (10) is at least partially located outside the orthographic projection of the light-emitting structure (20) on the bearing surface of the substrate (10).

7. The preparation method according to claim 6, characterized in that, The formation of a light-emitting structure (20) and a light-transmitting insulating layer (30) on the bearing surface of the substrate (10) includes: An epitaxial structure (21) is formed on the growth substrate (11); The epitaxial structure (21) is transferred to the bearing surface of the substrate (10), and the growth substrate (11) is removed. A reflective structure (22) is formed on the sidewall of the extensional structure (21); The light-transmitting insulating layer (30) is formed on the sidewall of the reflective structure (22).

8. The preparation method according to claim 7, characterized in that, The reflective structure (22) is formed on the sidewall of the epitaxial structure (21), comprising: A first insulating layer (221) is formed on the sidewall of the epitaxial structure (21). A metal reflective layer (222) is formed on the side of the first insulating layer (221) away from the epitaxial structure (21). A first reflective mirror layer (223) is formed on the side of the metal reflective layer (222) away from the first insulating layer (221) to form the reflective structure (22).

9. The preparation method according to claim 7, characterized in that, After forming the light-transmitting insulating layer (30) on the sidewall of the reflective structure (22), the method further includes: The sidewall of the light-transmitting insulating layer (30) away from the light-emitting structure (20) is roughened to form a roughened surface.

10. The preparation method according to claim 9, characterized in that, After roughening the sidewall of the light-transmitting insulating layer (30) away from the light-emitting structure (20), the method further includes: A silicon oxide layer is formed on the roughened surface.

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