A multi-unit light-emitting diode and a manufacturing method thereof

Abstract

The present invention provides a multi-unit light-emitting diode, which includes a substrate and n-unit epitaxial stacks disposed on the same-side surface of the substrate; the epitaxial stack sequentially includes a second semiconductor layer, a light-emitting layer, and a first semiconductor layer from bottom to top; and each unit includes a first platform exposing the surface of the first semiconductor layer and a second platform exposing the surface of the second semiconductor layer; a transparent conductive layer formed on the first platform of each unit; a conductive wiring layer electrically connected to the first semiconductor layer; a protective layer disposed below the conductive wiring layer; the protective layer is formed on the first platform and the second platform of each unit, and at least one or more protective layer through-holes are respectively provided on the transparent conductive layer and the second platform of each unit to expose the transparent conductive layer and the second platform of each unit.

Description

Technical Field

[0001] The present invention relates to a light-emitting device, and more particularly to a light-emitting diode with multiple units and a manufacturing method thereof. Background Art

[0002] With the continuous development of semiconductor technology, LED chips have dominated the lighting and display fields with advantages such as energy conservation, high brightness, high durability, long lifespan, and light weight. High-voltage LED chips solve the reliability problem of polycrystalline packaging and reduce energy loss in voltage conversion. In the chip manufacturing stage of high-voltage (HV) LED chips, the epitaxial layer is divided into a large number of high-voltage LED chips, and each high-voltage LED chip contains several independent die units, which are connected in series to form a high-voltage light-emitting diode. Compared with traditional LEDs, high-voltage LEDs reduce the number of wire bonding times in the packaging stage, and have advantages such as a simple and stable circuit design, high voltage conversion efficiency, and low energy loss. By freely adjusting voltage and current and effectively simplifying the LED drive circuit design and packaging, the light output efficiency is effectively improved.

[0003] Light-emitting diodes have advantages such as long lifespan, small size, low heat generation, and low power consumption; multi-unit light-emitting diodes have the advantages of high power, low packaging cost, and being easily made into extremely small components to meet application requirements, and have been widely used in household appliances and household lighting sources.

[0004] As shown in the Figures 1 to 3 accompanying figure, there is shown an existing multi-unit series-connected diode element; Figure 1 is a photomask diagram of an existing multi-unit light-emitting diode, Figure 2 and a top view structural diagram of an existing multi-unit light-emitting diode, Figure 3 is Figure 2 a side cross-sectional view taken along line A-A: including a transparent substrate 101, multiple light-emitting diode units 11 (including 11a and 11b) extending in a two-dimensional direction and closely arranged on the transparent substrate 101. The epitaxial stack of each light-emitting diode unit includes a buffer layer 111, a second semiconductor layer 112, a light-emitting layer 113, and a first semiconductor layer 114. A second platform is formed by partially etching the epitaxial stacks of multiple light-emitting diode units to the second semiconductor layer 112. Since the substrate 101 is non-conductive, trenches are etched between the epitaxial stacks of multiple light-emitting diode units to expose the substrate 101, so that the light diode units 11a and 11b are insulated from each other. Then, a conductive wiring layer 140 is formed on the second platform 122 and the first platform 124 of adjacent light-emitting diode units respectively, including a first electrode 141, a second electrode 142, and a connection electrode 144 connecting multiple light-emitting diode units 11. As shown in Figure 2As shown, the first electrode 141 and the second electrode 142 each further include a first pad 12a and a first extension bar 12b, and a second pad 13a and a second extension bar 13b, which are respectively formed on the transparent conductive layer 130 and the second platform 122 of adjacent light-emitting diode units to assist the uniform dispersion of current flowing into the epitaxial stack. By connecting the electrode 14, the second platform 122 on the first light-emitting diode unit 11a and the transparent conductive layer 130 on the second light-emitting diode unit 11b are connected, so that a series or parallel circuit connection is formed between the multiple light-emitting diode units 11. An insulating layer 120 is fabricated under the connection electrode structure 14 in the trench 10 to serve as electrical insulation between adjacent light-emitting diode units 11. The insulating layer 120 usually extends outward by 3 to 15 microns in accordance with the shape of the conductive wiring layer 140 to form a discontinuous surface structure on a multi-unit light-emitting diode. This chip manufacturing process generally includes at least six processes: etching the second semiconductor layer 112 (MESA) to expose the second platform 122, etching the insulating trench 10 to expose the substrate 110, fabricating the current blocking layer 120, fabricating the transparent conductive layer 130 (such as ITO), fabricating the conductive wiring layer 140, and fabricating the protective layer 150.

[0005] Based on the above description, the present invention provides a multi-unit light-emitting diode and its manufacturing method on this basis. Summary of the Invention

[0006] The object of the present invention is to provide a multi-unit light-emitting diode. By fabricating the protective layer before the conductive wiring layer, on the one hand, the protective layer protects the light-emitting diode from damage, and on the other hand, it can directly serve as a current blocking layer for current isolation under the connection bars between units and for suppressing over-injection of current under the extension bars, increasing the current diffusion of the transparent conductive layer; by performing ISO lithography before MESA lithography, MESA and ITO can be lithographed together, achieving high-voltage products with four photolithography steps, greatly reducing production costs and improving production efficiency.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] A multi-unit light-emitting diode includes:

[0009] A substrate, and an epitaxial stack of n units disposed on the same-side surface of the substrate;

[0010] Wherein, n≥2 and n is a positive integer, and the epitaxial stack sequentially includes a second semiconductor layer, a light-emitting layer, and a first semiconductor layer from bottom to top; and each unit includes a first platform exposing the surface of the first semiconductor layer and a second platform exposing the surface of the second semiconductor layer.

[0011] A transparent conductive layer, formed on the first platform of each unit;

[0012] A conductive wiring layer, including a first electrode, a second electrode, and a connecting electrode, electrically connected to the first semiconductor layer;

[0013] A protective layer, disposed under the conductive wiring layer; the protective layer is formed on the first platform and the second platform of each unit, and at least one protective layer through hole is provided on the transparent conductive layer and the second platform of each unit respectively, exposing the transparent conductive layer and the second platform of each unit; and the protective layer covers each unit, is formed on the first platform, the second platform, and the trenches between units of each unit, and is a continuous and uninterrupted film layer.

[0014] Further, the light-emitting diode further includes:

[0015] A first electrode, electrically connected to the first semiconductor layer of the first light-emitting diode unit through the protective layer through hole of the transparent conductive layer of the first light-emitting diode unit;

[0016] A second electrode, electrically connected to the second semiconductor layer of the nth unit through the protective layer through hole of the second platform of the nth unit;

[0017] A connecting electrode, composed of n - 1 connecting bars, each connecting bar electrically connects the second semiconductor layer of the mth unit and the first semiconductor layer of the (m + 1)th unit through the protective layer through hole of the second platform of the mth unit and the protective layer through hole of the transparent conductive layer of the (m + 1)th unit respectively, where n - 1 ≥ m ≥ 1 and m is a positive integer.

[0018] Further, the structure under the first electrode includes, from the self-luminous layer upwards in sequence, a first semiconductor layer, a transparent conductive layer, and a protective layer, where the refractive index n0 of the protective layer is less than the refractive index n1 of the transparent conductive layer.

[0019] Further, both the first electrode and the second electrode have a pad portion and an extension bar.

[0020] Further, the first electrode is composed of a first pad and a first extension bar, the first pad and the first extension bar are electrically connected to the first semiconductor layer through different protective layer through holes respectively, and the first pad and the first extension bar are electrically connected; the second electrode is composed of a second pad and a second extension bar, the second pad and the second extension bar are electrically connected to the second semiconductor layer through different protective layer through holes respectively, and the second pad and the second extension bar are electrically connected.

[0021] Furthermore, the area of the opening of the protective layer below the pad portions of the first electrode and the second electrode is smaller than the areas of the pad portions of the first electrode and the second electrode.

[0022] Furthermore, the material of the substrate includes one or several of sapphire, lithium aluminate, zinc oxide, gallium phosphide, glass, organic polymer sheet, aluminum nitride, gallium arsenide, silicon, silicon carbide, and diamond-like carbon.

[0023] Furthermore, the materials of the buffer layer, the second semiconductor layer, the light-emitting layer, and the first semiconductor layer include one or several of gallium, aluminum, indium, arsenic, phosphorus, nitrogen, and silicon.

[0024] Furthermore, the material of the protective layer includes one or several of aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, titanium dioxide, and tantalum pentoxide.

[0025] The manufacturing method of such a multi-unit light-emitting diode includes the following steps:

[0026] (1) Form an epitaxial stack on the substrate, which includes a buffer layer, a second semiconductor layer, a light-emitting layer, and a first semiconductor layer in sequence from bottom to top;

[0027] (2) Use photolithography technology to etch and form the exposed area of the second semiconductor layer of each light-emitting diode unit, which is called the second platform;

[0028] (3) Selectively remove part of the epitaxial stack by photolithography technology to expose the underlying substrate, which is called a trench here, so as to form a plurality of separately arranged light-emitting diode units on the substrate, which are electrically insulated from each other;

[0029] (4) Form a transparent conductive layer on the exposed first platform;

[0030] (5) Form a semiconductor protective layer on the transparent conductive layer and form openings at the corresponding positions of the electrodes; the coverage includes: the transparent conductive layer, the first platform, the second platform, the bottom and side walls of the trench, and the side walls of the first platform.

[0031] Furthermore, the steps further include:

[0032] (1) Form an epitaxial stack on the substrate, which includes a buffer layer, a second semiconductor layer, a light-emitting layer, and a first semiconductor layer in sequence from bottom to top;

[0033] (2) Deposit ITO: Deposit indium tin oxide on the second semiconductor layer 112 by sputtering or evaporation.

[0034] (3) Perform MESA photolithography; then use wet etching of ITO to form a transparent conductive layer;

[0035] (4) ICP etching of MESA: ICP etching forms the exposed area of the second semiconductor layer of each light-emitting diode unit, which is called the second platform here and serves as the formation platform for the subsequent conductive wiring layer;

[0036] (5) A semiconductor protective layer is formed on the transparent conductive layer and openings are formed at the corresponding positions of the electrodes; The coverage includes: the transparent conductive layer, the first platform, the second platform, the bottom and side walls of the trench, and the side wall of the first platform.

[0037] The advantages of the present invention are as follows:

[0038] 1. For the multi-unit light-emitting diode provided by the present invention, the protective layer is formed first and then the conductive wiring layer is formed. On the one hand, this protective layer can serve as a composite current blocking layer to suppress the over-injection of current below the conductive wiring layer and increase the current diffusion distance; On the other hand, it can also protect the light-emitting diode from damage, combining the effects of the protective layer;

[0039] 2. For the multi-unit light-emitting diode provided by the present invention, the protective layer is formed first and then the conductive wiring layer is formed, which can reduce the exposed area of the second semiconductor platform, obtain a larger light-emitting layer area, and improve the light emission amount;

[0040] 3. The stacking order of the protective layer and the transparent conductive layer below the electrode is different from the existing light-emitting diode order. From the light-emitting layer upwards in sequence are the first semiconductor layer, the transparent conductive layer, and the protective layer, forming an antireflection structure with a gradually decreasing refractive index upwards, which can effectively reduce the internal light reflection over a large area and increase the light extraction efficiency;

[0041] 4. For the manufacturing method of the multi-unit light-emitting diode provided by the present invention, the insulating layer and the protective layer are combined into one process first, and then the MESA and the TCL layer are combined into one photolithography process, simplifying the process flow and greatly reducing the production cost;

[0042] 5. For the manufacturing method of the multi-unit light-emitting diode provided by the present invention, the formed protective layer is a continuous film layer, improving the problem of over-etching caused by wet etching when defining the protective layer pattern between each unit in the existing process ( Figure 2 15 in it), resulting in poor yield and quality. Description of the Drawings

[0043] The present invention discloses a multi-unit light-emitting diode element structure. In order to make the description of the present invention more detailed and complete, please refer to the following drawings to further understand the present invention, which form a part of the specification and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In addition, the drawing data is a description summary and is not drawn to scale.

[0044] Figure 1 It is a mask diagram of an existing multi-unit light-emitting diode;

[0045] Figure 2 Existing top view structure diagram of a multi-unit light-emitting diode;

[0046] Figure 3 For Figure 2 Side sectional view taken along line A-A;

[0047] Figure 4 Photomask diagram of the light-emitting diode according to Embodiment 1 of the present invention;

[0048] Figure 5 Top view structure diagram of the chip in Embodiment 1;

[0049] Figure 6 Is along Figure 5 Side sectional view taken along line A-A;

[0050] Figure 7 Photomask diagram of the light-emitting diode according to Embodiment 2 of the present invention;

[0051] Figure 8 Top view structure diagram of the chip in Embodiment 2;

[0052] Figure 9 Is along Figure 8 Side sectional view taken along line A-A.

[0053] Among them, 101 is the substrate; 111 is the buffer layer; 112 is the second semiconductor layer; 113 is the light-emitting layer; 114 is the first semiconductor layer;

[0054] 10 is the trench; 11 is the light-emitting diode unit; 12a is the first pad; 12b is the first extension bar; 13a is the second pad; 13b is the second extension bar; 120 is the insulating layer; 122 is the second platform; 124 is the first platform; 130 is the transparent conductive layer; 140 is the conductive wiring layer; 141 is the first electrode; 142 is the second electrode; 144 is the connecting electrode; 150 is the protective layer. Detailed implementation manners

[0055] The present invention will be further described below in conjunction with the detailed implementation manners. The following embodiments are intended to illustrate the present invention rather than further limit the present invention. The technical means used in the following embodiments are conventional means well-known to those skilled in the art.

[0056] The present invention provides a multi-unit light-emitting diode, including:

[0057] A substrate, and an epitaxial stack of n units disposed on the same-side surface of the substrate;

[0058] Wherein, n≥2 and n is a positive integer. The epitaxial stack includes a second semiconductor layer, a light-emitting layer, and a first semiconductor layer in sequence from bottom to top. And each unit includes a first platform exposing the surface of the first semiconductor layer and a second platform exposing the surface of the second semiconductor layer.

[0059] A transparent conductive layer is formed on the first platform of each unit.

[0060] A conductive wiring layer includes a first electrode, a second electrode, and a connecting electrode, and is electrically connected to the first semiconductor layer.

[0061] A protective layer is disposed below the conductive wiring layer. The protective layer is formed on the first platform and the second platform of each unit, and at least one protective layer through hole is provided on the transparent conductive layer and the second platform of each unit to expose the transparent conductive layer and the second platform of each unit. And the protective layer covers each unit, is formed on the first platform, the second platform, and the trench between units, and is a continuous and uninterrupted film layer.

[0062] The first electrode is electrically connected to the first semiconductor layer of the first light-emitting diode unit through the protective layer through hole of the transparent conductive layer of the first light-emitting diode unit.

[0063] The second electrode is electrically connected to the second semiconductor layer of the nth unit through the protective layer through hole of the second platform of the nth unit.

[0064] The connecting electrode is composed of n - 1 connecting bars. Each connecting bar electrically connects the second semiconductor layer of the mth unit and the first semiconductor layer of the (m + 1)th unit through the protective layer through hole of the second platform of the mth unit and the protective layer through hole of the transparent conductive layer of the (m + 1)th unit, where n - 1≥m≥1 and m is a positive integer.

[0065] Wherein, the structure below the first electrode includes, in sequence from the light-emitting layer upwards, a first semiconductor layer, a transparent conductive layer, and a protective layer. Among them, the refractive index n0 of the protective layer is less than the refractive index n1 of the transparent conductive layer.

[0066] Both the first electrode and the second electrode have pad portions and extension bars; the first electrode is composed of a first pad and a first extension bar, the first pad and the first extension bar are respectively electrically connected to the first semiconductor layer through different protective layer through holes, and the first pad and the first extension bar are electrically connected; the second electrode is composed of a second pad and a second extension bar, the second pad and the second extension bar are respectively electrically connected to the second semiconductor layer through different protective layer through holes, and the second pad and the second extension bar are electrically connected; the area of the opening of the protective layer under the pad portions of the first electrode and the second electrode is smaller than the area of the pad portions of the first electrode and the second electrode.

[0067] In addition, the material of the substrate includes, but is not limited to, one or several of sapphire, lithium aluminate, zinc oxide, gallium phosphide, glass, organic polymer sheet, aluminum nitride, gallium arsenide, silicon, silicon carbide, and diamond-like carbon; the materials of the buffer layer, the second semiconductor layer, the light-emitting layer, and the first semiconductor layer include, but are not limited to, one or several of gallium, aluminum, indium, arsenic, phosphorus, nitrogen, and silicon; the material of the protective layer includes, but is not limited to, one or several of aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, titanium dioxide, and tantalum pentoxide.

[0068] The following uses specific embodiments to specifically illustrate the manufacturing method of this multi-unit light-emitting diode:

[0069] Embodiment 1

[0070] Referring to Figures 4 - 6 , it shows a manufacturing method of a multi-unit light-emitting diode according to an embodiment of the present invention. The manufactured multi-unit light-emitting diode has better light output efficiency and a simpler process flow;

[0071] Figure 4 is the photomask diagram of the light-emitting diode of Embodiment 1 of the present invention, Figure 5 is the top view structure diagram of the chip, Figure 6 is along Figure 5 the side cross-sectional view taken along line A-A;

[0072] The light-emitting diode includes: a substrate 101, on which n unit light-emitting epitaxial layers are provided, where n≥2 and n is a positive integer; in the illustration of this embodiment, for the sake of simplifying the illustration, Figure 4 a three-unit light-emitting diode with n = 3 is given in

[0073] The light-emitting epitaxial layer includes, from bottom to top, a buffer layer 111, a second semiconductor layer 112, a light-emitting layer 113, and a first semiconductor layer 114.

[0074] Among them, each unit includes a first platform 124 exposing the surface of the first semiconductor layer 114 and a second platform 122 exposing the surface of the second semiconductor layer 112;

[0075] The manufacturing method of the multi-unit light-emitting diode provided by the present invention includes the following steps:

[0076] First, using the traditional epitaxial growth manufacturing process, an epitaxial stack is formed on a growth substrate 101. The epitaxial layers include a buffer layer 111, a second semiconductor layer 112, a light-emitting layer 113, and a first semiconductor layer 114 from bottom to top. The material of the substrate 101 is sapphire;

[0077] Next, using photolithography technology, the exposed area of the second semiconductor layer 112 of each light-emitting diode unit is etched to form the second platform 122 here, which serves as the formation platform for the subsequent conductive wiring layer.

[0078] After that, part of the epitaxial stack is selectively removed by photolithography technology to expose the underlying substrate, which is called the trench 10 here, to form a plurality of light-emitting diode units arranged separately on the substrate, electrically insulated from each other.

[0079] The transparent conductive layer 130 is formed on the exposed first platform 124 and deposited by techniques such as sputtering and evaporation.

[0080] Then, the protective layer 150 is formed on the transparent conductive layer 130 and openings 121a - f are formed at the corresponding positions of the electrodes. It is deposited by techniques such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and sputtering. The coverage range is as Figure 6 shown; the specific coverage range includes: the transparent conductive layer 130, the first platform 124, the second platform 122, the bottom and side walls of the trench 10, and the side walls of the first platform, that is, covering the entire component, having the protection function for the epitaxial layer and the purpose of electrical insulation between adjacent light-emitting diode units 11;

[0081] At this time, a first pad 12a, a first extension bar 12b, a second pad 13a, and a second extension bar 13b are formed above the openings; among them, the first pad 12a and the first extension bar 12b are in contact with the transparent conductive layer through the annular openings 121a and 121b respectively, and the second pad 13a and the second extension bar 13b are located above the second platform and are in contact with the second platform through the openings 121d and the openings 121c respectively.

[0082] The conductive wiring layer 140 is formed on the protective layer 150 to form a first electrode 141, a second electrode 142, and a connecting electrode 144.

[0083] These mutually completely separated connecting electrodes 144 are arranged on the second platform 122 of the 11a unit in a single-direction distribution manner at one end, contact the second semiconductor layer 112 through the protective layer opening 121d, and the current passes through the second semiconductor layer 112, the light-emitting layer 113, and the first semiconductor layer 114 to electrically connect the conductive wiring layers 140 to each other;

[0084] These spatially separated conductive wiring layers 140 form connecting electrodes 144 between the units, and the other end continues to extend to the first semiconductor layer 114 platform of another adjacent light-emitting diode unit 11b, and contacts the transparent conductive layer 130 on the first semiconductor layer 114 through the protective layer opening 121f, so that two adjacent light-emitting diode units 11a and 11b are electrically connected in series.

[0085] In this embodiment, the light-emitting epitaxial layer forms a first platform 124, a second platform 122, and a series of through holes 112a penetrating the first semiconductor layer 114 and the light-emitting layer 113, exposing the second platform 122; the protective layer 150 covers the side walls of the through holes 112a, the transparent conductive layer 130, part of the first platform, the side walls of the trenches between the units, the substrate surface and the second platform exposed at the bottom of the trenches, and a reserved opening 121d is provided at the second platform, and the second electrode 142 is fabricated on the surface of the semiconductor protective layer 150, wherein the pad portion 13a of the second electrode contacts the second semiconductor layer 112 through the opening 121d, and the extension strip 13b contacts the second semiconductor layer 112 through the through hole 121c.

[0086] In this embodiment, by making the protective layer before the conductive wiring layer, on the one hand, the protective layer protects the light-emitting diode from damage, and on the other hand, it can directly serve as a current blocking layer for current isolation under the connecting strips between the units and suppressing over-injection of current under the extension strips, and increasing the current diffusion of the transparent conductive layer; the first electrode directly contacts the semiconductor layer in the pad area, effectively increasing the adhesion between the electrode and the epitaxial layer, and reducing the risk of the electrode and the attachment interface falling off during wire bonding.

[0087] Embodiment 2

[0088] Refer to Figures 7 - 9 , which shows a manufacturing method of a multi-unit light-emitting diode according to an embodiment of the present invention. The manufactured multi-unit light-emitting diode has better light output efficiency and a simpler process flow;

[0089] Figure 7 is the photomask diagram of the light-emitting diode of Embodiment 2 of the present invention, Figure 8 is the top view structure diagram of the chip, Figure 9 is Figure 8 a side cross-sectional view taken along line A-A;

[0090] The light-emitting diode includes: a substrate 101, on which an epitaxial light-emitting layer with n units is provided, where n≥2 and n is a positive integer; in the illustration of this embodiment, for the sake of simplifying the illustration, Figure 7 a three-unit light-emitting diode with n = 3 is given in

[0091] The light-emitting epitaxial layer sequentially includes a buffer layer 111, a second semiconductor layer 112, a light-emitting layer 113, and a first semiconductor layer 114 from bottom to top.

[0092] Among them, each unit includes a first platform 124 exposing the surface of the first semiconductor layer 114 and a second platform 122 exposing the surface of the second semiconductor layer 112;

[0093] The manufacturing method of the multi-unit light-emitting diode provided by the present invention includes the steps of:

[0094] First, by using the traditional epitaxial growth manufacturing process, an epitaxial stack is formed on a growth substrate 101. The epitaxial layer sequentially includes a buffer layer 111, a second semiconductor layer 112, a light-emitting layer 113, and a first semiconductor layer 114 from bottom to top, where the material of the substrate 101 is sapphire;

[0095] Next, part of the epitaxial stack is selectively removed by photolithography technology to expose the underlying substrate, which is called a trench 10 here, so as to form a plurality of separately arranged light-emitting diode units on the substrate, which are electrically insulated from each other.

[0096] Next, indium tin oxide is deposited on the second semiconductor layer 112 by sputtering; that is, ITO is deposited before MESA lithography; in other embodiments, sputtering can also be replaced by evaporation;

[0097] Next, MESA lithography is performed, and lithography is carried out by using the Figure 7 second mask in

[0098] Next, ICP etches the MESA, and the exposed area of the second semiconductor layer 112 of each light-emitting diode unit is formed by ICP etching, which is called the second platform 122 here, as the formation platform for the subsequent conductive wiring layer;

[0099] Next, a semiconductor protective layer 150 is formed on the transparent conductive layer 130 and openings 121a - f are formed at the corresponding positions of the electrodes, and are deposited by techniques such as chemical vapor deposition (CVD), physical vapor deposition (PVD), sputtering, etc., and the coverage range is as Figure 9As shown; the specific coverage includes: the transparent conductive layer 130, the first platform 124, the second platform 122, the bottom and side walls of the trench 10, and the side wall of the first platform, that is, it basically covers the entire component, and has the functions of protecting the epitaxial layer and electrical insulation between adjacent light-emitting diode units 11;

[0100] At this time, a first pad 12a, a first extension bar 12b, a second pad 13a, and a second extension bar 13b are formed above its opening; among them, the first pad 12a and the first extension bar 12b are in contact with the transparent conductive layer through the annular openings 121a and 121b respectively, and the second pad 13a and the second extension bar 13b are located above the second platform and are in contact with the second platform through the annular openings 121d and the openings 121c respectively.

[0101] The conductive wiring layer 140 is formed on the protective layer 150 and constitutes the first electrode 141, the second electrode 142, and the connection electrode 144.

[0102] These completely separated connection electrodes 144 are arranged on the second platform 122 of the 11a unit in a single-direction distribution manner at one end, and are in contact with the second semiconductor layer 112 through the protective layer opening 121d. The current passes through the second semiconductor layer 112, the light-emitting layer 113, and the first semiconductor layer 114 to electrically connect the conductive wiring layers 140 to each other; these spatially separated conductive wiring layers 140 form connection electrodes 144 between the units, and the other end continues to extend to the first semiconductor layer 114 platform of another adjacent light-emitting diode unit 11b and is in contact with the transparent conductive layer 130 on the first semiconductor layer 114 through the protective layer opening 121f, so that two adjacent light-emitting diode units 11a and 11b are electrically connected in series.

[0103] In this embodiment, the light-emitting epitaxial layer forms a first platform, a second platform, and a series of through holes 112a penetrating the first semiconductor layer 114 and the light-emitting layer 113, exposing the second platform; the protective layer 150 covers the side walls of the through holes 112a, the transparent conductive layer 130, part of the first platform, the side walls of the trenches between the units, the substrate surface exposed at the bottom of the trenches, and the second platform, and a ring-shaped opening 121d is reserved at the second platform. The second electrode 142 is made on the surface of the semiconductor protective layer 150, where the pad portion 13a of the second electrode is in contact with the second semiconductor layer 112 through the opening 121d, and the extension bar 13b is in contact with the second semiconductor layer 112 through the through hole 121c.

[0104] In this embodiment, on the one hand, the protective layer of the above-mentioned light-emitting diode protects the light-emitting diode from being damaged, and on the other hand, it can directly serve as a current blocking layer for current isolation under the connection bars between the units and suppressing over-injection of current under the extension bars, and increasing the current diffusion of the transparent conductive layer;

[0105] In this example, by performing ISO lithography before MESA lithography, MESA and ITO can be lithographed together, achieving high-voltage products with four lithography processes, that is, using Figure 7 the second mask in [[]] to complete the lithography of MESA and ITO in one lithography process, greatly simplifying the process flow and reducing production costs;

[0106] In this embodiment, the second electrode is in direct contact with the semiconductor layer in the pad area, effectively increasing the adhesion between the electrode and the epitaxial layer, and reducing the risk of the electrode detaching from the attachment interface during wire bonding.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced; and all technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered by the scope of the claims of the present invention.

Claims

1. A multi-unit light-emitting diode, characterized in that, Comprising: a substrate, and an epitaxial stack of n units disposed on the same-side surface of the substrate; wherein, n≥2 and n is a positive integer, the epitaxial stack sequentially includes a second semiconductor layer, a light-emitting layer, and a first semiconductor layer from bottom to top; and each unit includes a first platform exposing the surface of the first semiconductor layer and a second platform exposing the surface of the second semiconductor layer; a transparent conductive layer formed on the first platform of each unit; a conductive wiring layer including a first electrode, a second electrode, and a connection electrode, electrically connected to the first semiconductor layer; a protective layer disposed below the conductive wiring layer; the protective layer is formed on the first platform and the second platform of each unit, and at least one protective layer via hole is provided on the transparent conductive layer and the second platform of each unit to expose the transparent conductive layer and the second platform of each unit; and the protective layer covers each unit, is formed on the first platform, the second platform, and the inter-unit trench of each unit, and is a continuous and uninterrupted film layer; the protective layer via hole is used to realize the conductive connection between the transparent conductive layer and the second platform.

2. The multi-unit light-emitting diode according to claim 1, characterized in that, The light-emitting diode further includes: a first electrode electrically connected to the first semiconductor layer of the first light-emitting diode unit through the protective layer via hole of the transparent conductive layer of the first light-emitting diode unit; a second electrode electrically connected to the second semiconductor layer of the nth unit through the protective layer via hole of the second platform of the nth unit; a connection electrode composed of n - 1 connection bars, each connection bar electrically connects the second semiconductor layer of the mth unit and the first semiconductor layer of the m + 1th unit through the protective layer via hole of the second platform of the mth unit and the protective layer via hole of the transparent conductive layer of the m + 1th unit, where n - 1≥m≥1 and m is a positive integer.

3. The multi-unit light-emitting diode according to claim 2, wherein The structure below the first electrode includes, from the light-emitting layer upwards in sequence, a first semiconductor layer, a transparent conductive layer, and a protective layer, wherein the refractive index n0 of the protective layer is less than the refractive index n1 of the transparent conductive layer.

4. The multi-unit light-emitting diode according to claim 2, wherein, Both the first electrode and the second electrode have a pad portion and an extension bar.

5. The multi-unit light-emitting diode according to claim 4, characterized in that, The first electrode is composed of a first pad and a first extension bar, the first pad and the first extension bar are electrically connected to the first semiconductor layer through different protective layer via holes respectively, and the first pad and the first extension bar are electrically connected.

6. The multi-unit light-emitting diode according to claim 4, wherein, The second electrode is composed of a second pad and a second extension bar, the second pad and the second extension bar are electrically connected to the second semiconductor layer through different protective layer via holes respectively, and the second pad and the second extension bar are electrically connected.

7. The multi-unit light-emitting diode according to claim 4, characterized in that, The area of the opening of the protective layer below the pad portions of the first electrode and the second electrode is smaller than the area of the pad portions of the first electrode and the second electrode.

8. A manufacturing method of a multi-unit light-emitting diode according to any one of claims 1-7, characterized in that the steps Comprising: (1) forming an epitaxial stack on the substrate, sequentially including a buffer layer, a second semiconductor layer, a light-emitting layer, and a first semiconductor layer from bottom to top; (2) etching to form the exposed area of the second semiconductor layer of each light-emitting diode unit by photolithography technology, referred to as the second platform; (3) Selectively remove part of the epitaxial stack by lithography technology to expose the underlying substrate, which is called a trench here, so as to form a plurality of separately arranged light-emitting diode units on the substrate, which are electrically insulated from each other; (4) A transparent conductive layer is formed on the exposed first platform; (5) A semiconductor protective layer is formed on the transparent conductive layer and openings are formed at the corresponding positions of the electrodes; The coverage includes: the transparent conductive layer, the first platform, the second platform, the bottom and side walls of the trench, and the side wall of the first platform.

9. The manufacturing method of the multi-unit light-emitting diode according to claim 8, wherein, The steps also include: (1) Form an epitaxial stack on the substrate, which sequentially includes a buffer layer, a second semiconductor layer, a light-emitting layer, and a first semiconductor layer from bottom to top; (2) Deposit ITO: Deposit indium tin oxide on the second semiconductor layer by sputtering or evaporation; (3) Perform MESA lithography; then form a transparent conductive layer by wet etching of ITO; (4) ICP etch MESA: ICP etch to form the exposed area of the second semiconductor layer of each light-emitting diode unit, which is called the second platform here, as the formation platform for the subsequent conductive wiring layer; A semiconductor protective layer is formed on the transparent conductive layer and openings are formed at the corresponding positions of the electrodes; The coverage includes: the transparent conductive layer, the first platform, the second platform, the bottom and side walls of the trench, and the side wall of the first platform.

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