Light emitting diode and light emitting device

Abstract

This invention provides a light-emitting diode (LED) comprising an epitaxial structure, a via, a first insulating layer, a connecting electrode, a second insulating layer, and pads. The epitaxial structure includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked sequentially. The first insulating layer includes a first insulating portion and a second insulating portion covering the second semiconductor layer. The first insulating portion extends to the bottom of the via, and the second insulating portion is spaced apart from the first insulating portion by an annular second opening. A first connecting electrode is electrically connected to the first semiconductor layer through the first opening; a second connecting electrode is electrically connected to the second semiconductor layer through the second opening; the second insulating layer is located on the first and second connecting electrodes and has a third opening and a fourth opening; a first pad is electrically connected to the first connecting electrode through the third opening; and a second pad is electrically connected to the second connecting electrode through the fourth opening. This allows the two pads to have the same height, resulting in a highly consistent LED.

Description

[0001] This application is a divisional application of Chinese patent application filed on September 27, 2021 (application number CN202111138111.5, entitled "Light Emitting Diode and Light Emitting Device"). Technical Field

[0002] This invention relates to the field of light-emitting diode (LED) manufacturing technology, and in particular to an LED and light-emitting device with high uniformity. Background Technology

[0003] Light-emitting diodes (LEDs) have advantages such as low cost, high luminous efficiency, and energy saving, and are widely used in lighting, visible light communication, and light-emitting displays. LED chips are divided into three types: upright, flip-chip, and vertical. Compared with traditional upright chips, flip-chip LEDs invert the diode structure, emitting light from the sapphire side, while the electrode side can be fixed on a substrate with better heat dissipation.

[0004] Current flip-chip structures typically involve placing a metal reflective layer or an insulating reflective layer almost entirely on one side of the epitaxial structure. This allows the flip chip to emit light primarily from the top surface and sidewalls of the substrate. Metal reflective layers offer better current diffusion and heat dissipation compared to insulating reflective layers, and are mainly used in large-size, high-current driven LED chips. Flip-chips with metal reflective layers often have vias (e.g., extending from a P-type layer to an N-type layer) in the epitaxial structure. The numerous and thick metal and insulating layers on one side of the epitaxial structure result in low surface height uniformity on the vias covering the pad electrodes, with significant height differences exceeding 4 micrometers. Furthermore, metal layers of different polarities overlap in certain areas along the longitudinal direction. This leads to several problems, such as: after die bonding at the client end, the high void ratio in the electrode areas of the pads with significant height differences results in reduced thrust and weakened heat dissipation. Furthermore, during or after die bonding, the insulating layer is prone to breakage due to its brittleness when subjected to external forces, causing localized short circuits between metal layers of different polarities. Therefore, improving the surface flatness and thickness uniformity of the two pads in the LED chip structure, and preventing interconnection between metal layers of different polarities due to insulating layer breakage, has become a pressing technical challenge for those skilled in the art.

[0005] On the other hand, due to the metallic reactivity of the metal reflective layer, when a large area of ​​the metal reflective layer is placed inside the chip, the performance of the metal reflective layer will be damaged by water vapor erosion, especially under high current driving conditions, the failure rate will be accelerated. Therefore, it is crucial to protect the metal reflective layer from the inside out. Summary of the Invention

[0006] The present invention provides a light-emitting diode, which includes an epitaxial structure, a via, a first insulating layer, a first connecting electrode, a second connecting electrode, a second insulating layer, a first pad, and a second pad.

[0007] The epitaxial structure includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked from bottom to top. A via extends downwards from a portion of the upper surface of the second semiconductor layer through the light-emitting layer to the first semiconductor layer.

[0008] The first insulating layer includes a first insulating portion and a second insulating portion. The first insulating portion is located on a portion of the second semiconductor layer and extends to the bottom of the via, and the first insulating portion forms a first opening at the bottom of the via; the second insulating portion is located only on a portion of the second semiconductor layer, viewed from above the light-emitting diode toward the epitaxial structure, the first insulating portion surrounds the second insulating portion, and the first insulating portion and the second insulating portion are spaced apart by an annular second opening.

[0009] A first connecting electrode is located on the first insulating portion and is electrically connected to the first semiconductor layer through a first opening. A second connecting electrode covers the upper surface and sidewalls of the second insulating portion and is electrically connected to the second semiconductor layer through a second opening.

[0010] A second insulating layer is located on the first and second connecting electrodes and has a third and a fourth opening. A first pad is electrically connected to the first connecting electrode through the third opening. A second pad is electrically connected to the second connecting electrode through the fourth opening.

[0011] In one embodiment, the edges of the first pad and the second pad are both located on the upper surface of the second insulating layer. When viewed from above the light-emitting diode toward the epitaxial structure, there is a third distance between the edge of the first pad and the edge of the third opening, the third distance being between 5 micrometers and 20 micrometers. There is a fourth distance between the edge of the second pad and the edge of the fourth opening, the fourth distance being between 5 micrometers and 20 micrometers.

[0012] In one embodiment, the horizontal projected area of ​​the first pad accounts for more than 100% and less than or equal to 110% of the horizontal projected area of ​​the third opening; the horizontal projected area of ​​the second pad accounts for more than 100% and less than or equal to 110% of the horizontal projected area of ​​the fourth opening.

[0013] In one embodiment, the horizontal projected area of ​​the second insulating portion is greater than or equal to 50% of the horizontal projected area of ​​the second connecting electrode, and less than 100% of the horizontal projected area of ​​the second connecting electrode.

[0014] In one embodiment, the horizontal projected area of ​​the second insulating portion is between 30% and 70% of the horizontal projected area of ​​the first insulating portion.

[0015] In one embodiment, the horizontal projected area of ​​the second pad accounts for more than or equal to 90% and less than or equal to 100% of the horizontal projected area of ​​the second connecting electrode.

[0016] In one embodiment, when viewed from above the light-emitting diode toward the epitaxial structure, there is a first distance between the first insulating portion and the second insulating portion, the first distance being between 5 micrometers and 20 micrometers.

[0017] In one embodiment, viewed from above the light-emitting diode toward the epitaxial structure, there is a second distance between the edge of the second connecting electrode and the edge of the second pad, the second distance being between 15 micrometers and 50 micrometers.

[0018] In one embodiment, when viewed from above the light-emitting diode toward the epitaxial structure, there is a third distance between the first connecting electrode and the second connecting electrode, the third distance being 10 micrometers to 30 micrometers.

[0019] In one embodiment, the thickness of the first insulating portion is 0.8 micrometers to 1.5 micrometers.

[0020] In one embodiment, viewed from above the light-emitting diode toward the epitaxial structure, the via is located outside the first pad and the second pad.

[0021] In one embodiment, the light-emitting diode further includes a reflective layer and a blocking layer. The reflective layer is disposed on the second semiconductor layer, and the blocking layer covers the reflective layer. The first insulating portion and the second insulating portion cover a portion of the blocking layer, and the second opening exposes a portion of the blocking layer. The second connecting electrode is electrically connected to the blocking layer through the second opening.

[0022] In one embodiment, the horizontal projected area of ​​the reflective layer accounts for at least 80% of the horizontal projected area of ​​the second semiconductor layer.

[0023] In one embodiment, the light-emitting diode further includes a transparent conductive layer located between the second semiconductor layer and the reflective layer.

[0024] In one embodiment, viewed from above the light-emitting diode toward the epitaxial structure, the second insulating portion has a plurality of protrusions, each of the protrusions extending toward the first pad, and at least one via is provided between two adjacent protrusions.

[0025] In one embodiment, the second insulating portion has the same shape as the second connecting electrode.

[0026] In one embodiment, the first connection electrode further includes an extended electrode near the edge of the light-emitting diode.

[0027] In one embodiment, the second connecting electrode completely covers the second insulating portion.

[0028] The present invention also provides a light-emitting device that employs any of the light-emitting diodes described above. Furthermore, the light-emitting device can be used for vehicle lighting, backlighting, or general illumination.

[0029] One advantage of this invention is that it provides a light-emitting diode (LED) in which the upper surfaces of the first and second connecting electrodes are at the same height through the arrangement of the first and second insulating portions, resulting in an LED with relatively high height consistency. At the same time, the partial edges of the first and second pads are formed on the second insulating layer, and the first and second pads completely cover the openings of the second insulating layer. This ensures that the height of most of the upper surface area of ​​the first and second pads is as similar as possible, while preventing moisture intrusion and reducing the risk of corrosion or short circuits in the internal metal layers (such as the aluminum metal of the first or second connecting electrodes, or the large-area metal reflective layer such as aluminum or silver below), thereby improving reliability.

[0030] Another advantage of the present invention is that it provides a light-emitting diode that avoids the problem of local short circuit caused by the first insulating layer or the second insulating layer breaking under external force, which would result in the interconnection of metal layers with different polarities, by means that the horizontal projections of the first connecting electrode and the second pad do not overlap, and the horizontal projections of the second connecting electrode and the first pad do not overlap.

[0031] Another advantage of the present invention is that it provides a light-emitting diode in which the area of ​​the third opening is greater than or equal to 80% of the area of ​​the first pad and the area of ​​the fourth opening is greater than or equal to 80% of the area of ​​the second pad, thereby improving the overall heat dissipation capability of the light-emitting diode.

[0032] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained by means of the structures particularly pointed out in the description, claims, etc. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0034] Figure 1 This is a top view schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present invention;

[0035] Figure 2 yes Figure 1 Enlarged view of point C in the middle;

[0036] Figure 3 It is along Figure 1 A schematic diagram of the longitudinal section cut by the intercept line AA;

[0037] Figures 4 to 11 This is a top view structural diagram of a light-emitting diode at various stages of the manufacturing process according to an embodiment of the present invention;

[0038] Figure 12 This is a cross-sectional schematic diagram of a light-emitting diode provided in another embodiment of the present invention.

[0039] Figure label:

[0040] 10, 70 - Light Emitting Diode; 11 - Substrate; 12 - Epitaxial Structure; 121 - First Semiconductor Layer; 122 - Second Semiconductor Layer; 123 - Light Emitting Layer; 13 - Via; 14 - First Insulating Layer; 141 - First Insulating Part; 142 - Second Insulating Part; 143 - First Opening; 144 - Second Opening; 146 - Protrusion; 16 - Second Insulating Layer; 163 - Third Opening; 164 - Fourth Opening; 18 - Transparent Conductive Layer; 19 - Reflective Layer; 20 - Barrier Layer; 21 - First Connecting Electrode; 212 - Extended Electrode; 22 - Second Connecting Electrode; 222 - Protrusion; 31 - First Pad; 32 - Second Pad; D1 - First Distance; D2 - Second Distance; D3 - Third Distance; D4 - Fourth Distance; D5 - Fifth Distance; D6 - Sixth Distance; D7 - Seventh Distance. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0045] Please see Figure 1 , Figure 2 and Figure 3 , Figure 1 This is a top view schematic diagram of the light-emitting diode 10 provided in an embodiment of the present invention. Figure 2 yes Figure 1 Enlarged diagram of point C in the middle. Figure 3 It is along Figure 1 A longitudinal cross-sectional view taken by the intercept line AA. To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a light-emitting diode 10. As shown in the figure, the light-emitting diode 10 includes an epitaxial structure 12, a via 13, a first insulating layer 14, a first connecting electrode 21, a second connecting electrode 22, a second insulating layer 16, a first pad 31, and a second pad 32.

[0046] The epitaxial structure 12 is disposed on the substrate 11. The substrate 11 can be a transparent substrate, a non-transparent substrate, or a semi-transparent substrate. The transparent or semi-transparent substrate allows light radiated from the light-emitting layer to pass through the substrate 11 and reach the side of the substrate 11 away from the epitaxial structure 12. For example, the substrate 11 can be any one of a sapphire flat substrate, a sapphire patterned substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, or a glass substrate.

[0047] The epitaxial structure 12 includes, from bottom to top, a first semiconductor layer 121, a light-emitting layer 123, and a second semiconductor layer 122 stacked sequentially.

[0048] The first semiconductor layer 121 is connected to the substrate 11. As a layer grown on the substrate 11, the first semiconductor layer 121 can be a gallium nitride semiconductor layer doped with n-type impurities, such as Si.

[0049] The light-emitting layer 123 can have a single quantum well structure or a multiple quantum well structure. The composition and thickness of the well layers within the light-emitting layer 123 determine the wavelength of the generated light. In particular, by adjusting the composition of the well layers, a light-emitting layer 123 can be provided to generate different colors of light, such as ultraviolet light, blue light, and green light.

[0050] The second semiconductor layer 122 can be a gallium nitride semiconductor layer doped with p-type impurities, such as Mg. While the first semiconductor layer 121 and the second semiconductor layer 122 can each be a single layer, this invention is not limited to this; they can also be multiple layers, and may include a superlattice layer. The first semiconductor layer 121, the light-emitting layer 123, and the second semiconductor layer 122 can be formed on the substrate 11 using methods such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). Furthermore, if the first semiconductor layer 121 is doped with p-type impurities, the second semiconductor layer 122 is doped with n-type impurities. A transition layer or buffer layer (not shown in the figure), such as an aluminum nitride layer or a gallium nitride layer, can also be provided between the first semiconductor layer 121 and the substrate 11, which is beneficial for improving the formation quality of the first semiconductor layer 121, the light-emitting layer 123, and the second semiconductor layer 122 on the substrate.

[0051] The via 13 extends downwards from a portion of the upper surface of the second semiconductor layer 122 through the light-emitting layer 123 to the first semiconductor layer 121, that is, it penetrates from the second semiconductor layer 122 to the first semiconductor layer 121, exposing a portion of the first semiconductor layer 121. The horizontal area of ​​the first semiconductor layer 121 is larger than the horizontal area of ​​the light-emitting layer 123 and also larger than the horizontal area of ​​the second semiconductor layer 122. For example... Figure 1 As shown, the light-emitting diode 10 can be provided with multiple vias 13, and each via 13 is circular in shape. However, this invention is not limited to this. The shape and number of vias 13 are not particularly limited. If multiple vias 13 are provided, the current can be distributed more evenly, resulting in better performance. In addition, the vias 13 can be selected in a uniform or non-uniform spacing distribution form according to actual needs.

[0052] A transparent conductive layer 18 is located on the second semiconductor layer 122 and is in direct contact with the second semiconductor layer 122. The transparent conductive layer 18 avoids the location of the via 13 and is formed on almost the entire surface of the second semiconductor layer 122. The transparent conductive layer 18 is made of a transparent and conductive oxide material, which ensures ohmic contact and lateral current spreading effect.

[0053] A reflective layer 19 is disposed on the second semiconductor layer 122, specifically on the transparent conductive layer 18. The reflective layer 19 is in contact with the transparent conductive layer 18 and is used to reflect light generated from the light-emitting layer 123 and traveling to the upper side towards the substrate 11. The horizontal projected area of ​​the reflective layer 19 accounts for at least 80% of the horizontal projected area of ​​the second semiconductor layer 122. In other words, the coverage area of ​​the reflective layer 19 is at least 80% of the area of ​​the second semiconductor layer 122. The larger the horizontal projected area of ​​the second semiconductor layer 122 occupied by the reflective layer 19, the better. A blocking layer 20 is disposed on the reflective layer 19, and the blocking layer 20 covers the upper surface and edge sidewalls of the reflective layer 19, preventing the reflection layer 19 from diffusing.

[0054] The first insulating layer 14 covers the barrier layer 20 above the epitaxial structure 12 and around the sidewalls of the epitaxial structure 12, and extends to cover the substrate 11 surrounding the epitaxial structure 12. The first insulating layer 14 includes a first insulating portion 141 and a second insulating portion 142. The first insulating portion 141 is located on the barrier layer 20 on a portion of the second semiconductor layer 122 and extends to the bottom of the via 13, and the first insulating portion 141 forms a first opening 143 at the bottom of the via 13, in other words, the first opening 143 of the first insulating portion 141 is located inside the via 13.

[0055] The second insulating portion 142 is located only on a portion of the second semiconductor layer 122, viewed from above the light-emitting diode 10 towards the epitaxial structure 12, i.e., as shown in the image. Figure 1 As shown, the first insulating portion 141 surrounds the second insulating portion 142, and the first insulating portion 141 and the second insulating portion 142 are spaced apart by an annular second opening 144. The second opening 144 is located above the second semiconductor layer 122.

[0056] Specifically, the first insulating part 141 and the second insulating part 142 cover the barrier layer 20. The first opening 143 of the first insulating part 141 is located inside the through hole 13, and the second opening 144 exposes part of the barrier layer 20. The second connecting electrode 22 is electrically connected to the barrier layer 20 through the second opening 144.

[0057] The first insulating layer 14 has different functions depending on the location involved. For example, the portion covering the sidewall of the epitaxial structure 12 is to prevent the conductive material from leaking electrical connections between the first semiconductor layer 121 and the second semiconductor layer 122, and to reduce short-circuit abnormalities of the light-emitting diode 10 chip. However, the embodiments disclosed herein are not limited thereto.

[0058] The first connecting electrode 21 is located on the first insulating portion 141 and extends to the bottom of the first opening 143, electrically connecting to the first semiconductor layer 121. The second connecting electrode 22 covers the upper surface and sidewalls of the second insulating portion 142, that is, the second connecting electrode 22 completely covers the entire second insulating portion 142, and the edge of the second connecting electrode 22 extends into the second opening 144, electrically connecting to the second semiconductor layer 122. Most of the second connecting electrode 22 is supported by the second insulating portion 142, and the second connecting electrode 22 contacts the barrier layer 20 from the periphery of the second insulating portion 142. Preferably, the second connecting electrode 22 completely covers the second insulating portion 142, that is, the second connecting electrode 22 covers the upper surface and sidewalls of the second insulating portion 142. Preferably, the edge of the second connecting electrode 22 is located in the annular second opening 144.

[0059] The second insulating layer 16 is located on the first connecting electrode 21 and the second connecting electrode 22, and has a third opening 163 and a fourth opening 164. The third opening 163 is located above the first connecting electrode 21, and the fourth opening 164 is located above the second connecting electrode 22. The second insulating layer 16 also covers the sidewalls of the epitaxial structure 12.

[0060] Both the first pad 31 and the second pad 32 are located on the second insulating layer 16. The first pad 31 is electrically connected to the first connecting electrode 21 through the third opening 163. The second pad 32 is electrically connected to the second connecting electrode 22 through the fourth opening 164. The first pad 31 and the second pad 32 can be formed together in the same process using the same material, and therefore can have the same layer structure. The first pad 31 and the second pad 32 can be comb-shaped metal layers; as an example, the first pad 31 can be an N-pad, and the second pad 32 can be a P-pad.

[0061] The light-emitting diode 10 provided in this embodiment supports the first connecting electrode 21 through the first insulating part 141 and the second connecting electrode 22 through the second insulating part 142, so that the upper surfaces of the first connecting electrode 21 and the second connecting electrode 22 are at the same height, thereby ensuring that the upper surfaces of the first pad 31 on the first connecting electrode 21 and the second pad 32 on the second connecting electrode 22 are as similar as possible, resulting in a light-emitting diode 10 with high height consistency.

[0062] For flip-chip LEDs that rely on a metal reflective layer to enhance brightness, especially for large-size chips driven by high current, and applied in fields requiring high luminous efficiency and high reliability, such as automotive lighting, in addition to ensuring high chip consistency, protection against short circuits and water vapor erosion are also crucial reliability requirements. Based on this, this patent proposes forming partial edges of the first pad 31 and the second pad 32 on the second insulating layer 16. The first pad 31 and the second pad 32 completely cover the openings of the second insulating layer 16 (including but not limited to the third opening 163 and the fourth opening 164). This ensures that the height of most of the upper surface area of ​​the first pad 31 and the second pad 32 is as similar as possible, while also preventing the existence of pathways for water vapor to penetrate the interior, such as from around the pads. This reduces the risk of corrosion or short circuits in the internal metal layers (e.g., the aluminum of the first connecting electrode 21 or the second connecting electrode 22); simultaneously, it avoids the risk of water flowing directionally under the influence of an electric field, connecting metals of different polarities and causing short circuits.

[0063] In one embodiment, the thickness of the first insulating portion 141 can be 0.8 micrometers to 1.5 micrometers. The relatively thick first insulating portion 141 provides good insulation and isolation between the large-area first connecting electrode 21 and the barrier layer 20 below it.

[0064] The third opening 163 is located on the first connecting electrode 21, and the fourth opening 164 is located on the second connecting electrode 22. Preferably, both the third opening 163 and the fourth opening 164 are designed to avoid the via 13, and the third opening 163 and the fourth opening 164 have the same shape and similar area, and the first pad 31 and the second pad 32 have the same shape and similar area. Preferably, the area ratio of the first pad 31 to the area ratio of the second pad 32 is more than 80%.

[0065] Furthermore, when the second pad 32 is subjected to external force, causing the second insulating portion 142 below it to break, since the second insulating portion 142 and the first insulating portion 141 are separated by the annular second opening 144, the broken second insulating portion 142 will not cause the first insulating portion 141 to also break due to the internal stress transmitted to the first insulating portion 141, or prevent the crack from being transmitted to the first insulating portion 141 and causing the first insulating portion 141 to also crack. To a certain extent, this avoids the problem of local short circuit caused by the interconnection between the first connecting electrode 21 and the lower barrier layer 20.

[0066] In one embodiment, such as Figure 1As shown, viewed from above the LED 10 towards the epitaxial structure 12, the second insulating portion 142 is spaced apart from the first insulating portion 141. The second insulating portion 142 and the annular second opening 144 can be comb-shaped. Specifically, the second insulating portion 142 has multiple protrusions 146, each protruding horizontally towards the first pad 31. At least one through-hole 13 is provided between two adjacent protrusions 146, which not only improves the support for the second connecting electrode 22 but also avoids the through-hole 13 to ensure the surface of the second connecting electrode 22 is flat and ensures the film layer of the second connecting electrode 22 is dense and continuous. The spacing between two adjacent protrusions 146 can be equal. Preferably, the shape of the second connecting electrode 22 can be the same as the shape of the second insulating portion 142; in other words, the second connecting electrode 22 can also have multiple protrusions 222 with the same shape as the multiple protrusions 146 of the second insulating portion 142. Each protrusion 222 completely covers the protrusion 146 to enhance current spreading performance, and at least one through hole 13 is provided between two adjacent protrusions 222. Each protrusion 222 avoids the through hole 13 to ensure that the first pad 31 and the second pad 32 are on the same horizontal plane.

[0067] In one embodiment, such as Figure 1 As shown, to ensure that the upper surfaces of the first connecting electrode 21 and the second connecting electrode 22 are at the same height, the first pad 31 and the second pad 32 above the first connecting electrode 21 and the second connecting electrode 22 are at the same height. When the second insulating portion 142 has multiple protrusions 146, the first connecting electrode 21 and the second connecting electrode 22 are almost entirely located on the first insulating layer 14. The large areas formed on the first insulating portion 141 and the second insulating portion 142 ensure that the upper surfaces of the first connecting electrode 21 and the second connecting electrode 22 are as equal in height as possible. Specifically, the horizontal projected area of ​​the second insulating portion 142 is greater than or equal to 50% of the horizontal projected area of ​​the second connecting electrode 22. Preferably, the higher the ratio of the horizontal projected area of ​​the second insulating portion 142 to the horizontal projected area of ​​the second connecting electrode 22, the better; ideally, the ratio should be 80% or higher, for example, 80% or 90%.

[0068] To further explain, the horizontal projected area refers to the projected area of ​​each component (such as the fourth opening 164, the first connecting electrode 21, etc.) onto the horizontal surface when the light-emitting diode 10 is placed upright on the horizontal surface and the direction from the epitaxial structure 12 to the pad is a vertical direction perpendicular to the horizontal surface.

[0069] In one embodiment, viewed from above the light-emitting diode 10 toward the epitaxial structure 12, i.e., as shown... Figure 1 , Figure 2 As shown, when the second insulating portion 142 has multiple protrusions 146, the horizontal projected area of ​​the second insulating portion 142 is less than 100% of the horizontal projected area of ​​the second connecting electrode 22, and there is a first distance D1 between the edge of the first insulating portion 141 and the edge of the second insulating portion 142. This first distance D1 is also the opening width of the annular second opening 144. The first distance D1 is between 5 micrometers and 20 micrometers to leave sufficient width for the second connecting electrode 22 to be electrically connected to the barrier layer 20 through the annular second opening 144, so as to be further electrically connected to the second semiconductor layer 122. At the same time, the design of the annular second opening 144 is conducive to the current transmission between the second connecting electrode 22 and the barrier layer 20 through the annular second opening 144, and the current is rapidly extended horizontally to all sides from below the second connecting electrode 22 through the barrier 20, thereby improving the brightness uniformity and absolute brightness value of the entire light-emitting diode 10.

[0070] In one embodiment, such as Figure 1 As shown, while ensuring the insulation effect of the first insulating layer 14 on the epitaxial structure 12, the horizontal projected area of ​​the second insulating part 142 can be between 30% and 70% of the horizontal projected area of ​​the first insulating part 141, depending on the area requirement of the second connecting electrode 22.

[0071] In one embodiment, viewed from above the light-emitting diode 10 toward the epitaxial structure 12, i.e., as shown... Figure 1 , Figure 2 As shown, when the second insulating portion 142 has multiple protrusions 146 and the annular second opening 144 is comb-shaped, there is a third distance D3 between the edge of the first connecting electrode 21 and the edge of the second connecting electrode 22, and the third distance D3 is 10 micrometers to 30 micrometers.

[0072] The third opening 163 of the second insulating layer 16 is located above the first insulating portion 141, and the fourth opening 164 of the second insulating layer 16 is located above the second insulating portion 141.

[0073] In order to achieve the same height for the first pad 31 and the second pad 32, the third opening 163 is formed on the surface of the first connecting electrode 21 with the largest possible area, and the fourth opening 164 is formed on the surface of the second connecting electrode 22 with the largest possible area. The first pad 31 can be filled into the third opening 163 with the largest possible area, and the second pad 32 can be filled into the fourth opening 164 with the largest possible area. This can also improve the overall heat dissipation capacity of the light-emitting diode 10.

[0074] In one embodiment, such as Figure 1 , Figure 2As shown, the horizontal projected area of ​​the first pad 31 is greater than 100% and less than or equal to 110% of the horizontal projected area of ​​the third opening 163 of the second insulating layer 16; the horizontal projected area of ​​the second pad 32 is greater than 100% and less than or equal to 110% of the horizontal projected area of ​​the fourth opening 164. Exceeding this area ratio will affect the performance of making the first pad and the second pad as equal in height as possible.

[0075] In one embodiment, such as Figure 1 As shown, in order to ensure that the surfaces of the first pad 31 and the second pad 32 are flat and to ensure a low die-bonding void ratio when the client is installed and used, when viewed from above the LED 10 toward the epitaxial structure 12, the first pad 31 and the second pad 32 are arranged to avoid the via 13 when the second insulating portion 142 has multiple protrusions 146.

[0076] The second pad 32 fills the fourth opening 164, and optionally, the edge of the second pad 32 may extend with a small width over the second insulating layer 16 surrounding the fourth opening 164. Preferably, viewed from above the LED 10 toward the epitaxial structure 12, when the second insulating portion 142 has a plurality of protrusions 146, the edge of the second pad 32 extends over the second insulating layer 16, and there is a fifth distance D5 between the edge of the second pad 32 and the edge of the fourth opening 164, the fifth distance D5 being between 5 micrometers and 20 micrometers. Similarly, optionally, the edge of the first pad 31 may extend with a small width over the second insulating layer 16, i.e., there is a fourth distance D4 between the edge of the first pad 31 and the edge of the third opening 163, the fourth distance D4 being between 5 micrometers and 20 micrometers.

[0077] In one embodiment, viewed from above the light-emitting diode 10 toward the epitaxial structure 12, i.e., as shown... Figure 1 , Figure 2 As shown, when the second insulating portion 142 has a plurality of protrusions 146 and the annular second opening 144 is comb-shaped, a seventh distance D7 may be provided between the edge of the fourth opening 164 and the edge of the second connecting electrode 22. The seventh distance D7 ranges from 20 micrometers to 40 micrometers.

[0078] In one embodiment, viewed from above the light-emitting diode 10 toward the epitaxial structure 12, i.e., as shown... Figure 1 , Figure 2 As shown, when the second insulating portion 142 has a plurality of protrusions 146 and the annular second opening 144 is comb-shaped, the annular second opening 144 has a sixth distance D6 between the edge of the first insulating portion 141 and the first connecting electrode 21, and the sixth distance D6 ranges from 10 micrometers to 20 micrometers.

[0079] In one embodiment, such as Figure 1 As shown, to avoid localized short circuits caused by the interconnection of pads with different polarities with the connecting electrode due to the breakage of the first insulating layer 14 or the second insulating layer 16, as an alternative implementation, viewed from above the LED 10 towards the epitaxial structure 12, the first connecting electrode 21 is located around the second pad 32, the second pad 32 does not overlap with the first connecting electrode 21, the first pad 31 does not overlap with the second connecting electrode 22, the second pad 32 is only located on the second connecting electrode 22, and the horizontal projected area of ​​the second pad 32 accounts for more than or equal to 90% and less than or equal to 100% of the horizontal projected area of ​​the second connecting electrode 22. Furthermore, the first pad 31 is only located on the first connecting electrode 21 to form a second pad 32 with the largest possible area on the second connecting electrode 22.

[0080] More preferably, based on the precision control requirements of the process, the horizontal projected area of ​​the second pad 32 is prevented from exceeding the horizontal projected area of ​​the second connecting electrode 22, wherein the horizontal projected area of ​​the second pad 32 is smaller than the horizontal projected area of ​​the second connecting electrode 22.

[0081] Viewed from above the light-emitting diode 10 towards the epitaxial structure 12, i.e. Figure 1 , Figure 2 As shown, when the second insulating portion 142 has multiple protrusions 146, the second pad 32 does not extend beyond the area where the second connecting electrode 22 is located, and there may be a second distance D2 between the edge of the second connecting electrode 22 and the edge of the second pad 32, the second distance D2 being between 15 micrometers and 50 micrometers.

[0082] In some embodiments, the transparent conductive layer 18 may be made of a transparent conductive material. By using the transparent conductive layer 18 of a conductive oxide, ohmic contact and lateral current spreading effects can be ensured. As examples, the transparent conductive material may include indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium-doped zinc oxide (GZO), tungsten-doped indium oxide (IWO), or zinc oxide (ZnO), but the embodiments disclosed herein are not limited thereto. The thickness of the optional transparent conductive layer 140 is selected from 10 to 150 nm, more preferably from 30 to 120 nm.

[0083] Both the reflective layer 19 and the blocking layer 20 are made of metal. The reflective layer 19 is preferably formed by a combination of one or more metals such as silver, aluminum, titanium, tungsten, titanium-tungsten, and nickel. The blocking layer 20 can be formed by a combination of one or more metals such as Cr, Ti, Ni, Au, Al, or Pt.

[0084] The reflective layer 19 is preferably made of silver. When current passes through the reflective layer 19, the silver will migrate due to factors such as heat or electrical current. Therefore, the reflective layer 19 needs to be protected to prevent its own material migration. When the material of the reflective layer 19 migrates, silver or aluminum metal ions will diffuse into the chip interior in a disordered or ordered state, causing local leakage and chip failure. The silver reflective layer is also susceptible to moisture corrosion, and the corrosion will be more severe under the influence of an applied electric field. Therefore, protection from the inside out is very important.

[0085] In one embodiment, the materials of the first insulating layer 14 and the second insulating layer 16 comprise non-conductive materials. The non-conductive materials are preferably inorganic or dielectric materials. Inorganic materials include silicone or glass. Dielectric materials include electrically insulating materials such as alumina (AlO), silicon nitride (SiNx), silicon oxide (SiOx), titanium oxide (TiOx), or magnesium fluoride (MgF2). For example, the first insulating layer 14 can be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or combinations thereof, such as a Bragg reflector (DBR) formed by repeatedly stacking two materials. The materials and structures of the first insulating layer 14 and the second insulating layer 16 can be the same or different.

[0086] Preferably, the first connecting electrode 21 and the second connecting electrode 22 may comprise a layer formed by at least one element of metal such as titanium, aluminum, gold, platinum, chromium, and nickel, or a multilayer formed by a combination of multiple elements; the first pad 31 and the second pad 32 may comprise a combination of at least one layer of aluminum, titanium, nickel, gold, or gold-tin.

[0087] Please see Figures 4 to 11 , Figures 4 to 11 This is a top view schematic diagram of the light-emitting diode 10 provided in an embodiment of the present invention at various stages of the manufacturing process. It should be noted that the shaded areas in each figure represent the additional structures in the current process compared to the previous process.

[0088] First, refer to Figure 4 An epitaxial structure 12, comprising a first semiconductor layer 121, a light-emitting layer 123, and a second semiconductor layer 122, is grown on the substrate 11. Then, etching is performed starting from the second semiconductor layer 122 and continuing until the first semiconductor layer 121 is reached, forming a plurality of vias 13. Furthermore, the edge portions of the epitaxial structure 12 can be selectively removed to further expose the substrate 11, facilitating subsequent processes such as dicing.

[0089] Reference Figure 5 A transparent conductive layer 18 is formed on the second semiconductor layer 122 to enhance conductivity. The transparent conductive layer 18 has an opening on the outside of each via 13 to expose the first semiconductor layer 121.

[0090] Referring to Figure 6, a reflective layer 19 is formed on the transparent conductive layer 18 to reflect light out through the substrate 11. The reflective layer 19 is a metallic reflective layer, which can be formed using a lift-off technique. The reflective layer 19 can be formed as a single layer or a multilayer structure, and the layer structure can be formed using electron beam evaporation or magnetron sputtering. In one embodiment, this reflective layer 19 does not cover the via 13 and the edges of the substrate 11.

[0091] Reference Figure 7 A barrier layer 20 is formed on the reflective layer 19 to prevent material migration of the reflective layer 19. The barrier layer 20 is formed of a metallic material. Preferably, the barrier layer 20 can cover the sides of the reflective layer 19 to completely enclose the reflective layer 19.

[0092] Referring to Figure 8, a first insulating layer 14 is formed on the barrier layer 20. The first insulating layer 14 may cover a portion of the first semiconductor layer 121, the light-emitting layer 123, the second semiconductor layer 122, and a portion of the barrier layer 20. The first insulating layer 14 has a first opening 143 and a second opening 144 on the barrier layer 20. The first opening 143 is located within the via 13 and is used to expose the first semiconductor layer 121. The second opening 144 is located on the barrier layer 20 and is used to expose the barrier layer 20.

[0093] Reference Figure 9 A first connecting electrode 21 and a second connecting electrode 22 are formed on the first insulating layer 14. The first connecting electrode 21 and the second connecting electrode 22 are disposed on the first insulating layer 14 at a predetermined distance to isolate electrical properties. The predetermined distance refers to the width of the blank portion between the two shaded structures in the figure, i.e. Figure 3 The lateral spacing between the first connecting electrode 21 and the second connecting electrode 22 is preferably between 5 and 50 micrometers. Except for the area providing the spacing, the first connecting electrode 21 and the second connecting electrode 22 can almost completely cover the epitaxial structure 12.

[0094] The first connecting electrode 21 covers the via 13 and the first opening 143, and is electrically connected to the first semiconductor layer 121 through the first opening 143; the second connecting electrode 22 covers at least part of the second opening 144, and is electrically connected to the second semiconductor layer 122 through the second opening 144. The via 13 and the second connecting electrode 22 do not overlap.

[0095] Reference Figure 10 A second insulating layer 16 is formed on the first connecting electrode 21 and the second connecting electrode 22. Specifically, the second insulating layer 16 covers the first connecting electrode 21 and the second connecting electrode 22, and covers the first insulating layer 14 and the substrate 11. The second insulating layer 16 has a third opening 163 and a fourth opening 164. The third opening 163 is located above the first connecting electrode 21, and the fourth opening 164 is located above the second connecting electrode 22. In one embodiment, the shape of the fourth opening 164 is the same as or similar to the shape of the second connecting electrode 22, so as to ensure that the opening of the fourth opening 164 can fit as close as possible to the edge of the second connecting electrode 22.

[0096] Reference Figure 11A first pad 31 and a second pad 32 are formed on the second insulating layer 16. The first pad 31 and the second pad 32 are disposed on the second insulating layer 16 at a certain distance. The first pad 31 is electrically connected to the first connecting electrode 21 through a third opening 163, and the second pad 32 is electrically connected to the second connecting electrode 22 through a fourth opening 164. The first pad 31 and the second pad 32 can completely cover the third opening 163 and the fourth opening 164, respectively.

[0097] In one embodiment, such as Figure 12 As shown, compared to Figure 1 , Figure 3 Regarding the light-emitting diode 10 shown, Figure 12 The illustrated light-emitting diode 70 further includes an extended electrode 212. The epitaxial structure 12 has a mesa exposing a portion of the first semiconductor layer. This extended electrode 212 is disposed near the edge of the epitaxial structure 12, that is, a surrounding extended electrode 212 is disposed at the edge of the epitaxial structure 12. The extended electrode 212 extends downward from a portion of the upper surface of the first insulating portion 141 to cover the first semiconductor layer 121 at the mesa, thereby achieving a current spreading effect and improving the light emission performance of the light-emitting diode 70. The extended electrode 212 may be formed by extending the first connecting electrode 21 to increase current spreading.

[0098] The length or width of the light-emitting diodes 10 and 70 is between 500 micrometers and 2000 micrometers, and the ratio of the length to the width is between 1:1 and 2:1.

[0099] This embodiment provides a light-emitting module, which uses the light-emitting diodes 10 and 70 provided in any of the above embodiments. The specific structure and technical effects will not be described in detail.

[0100] This embodiment provides a light-emitting device that uses the light-emitting diodes 10 and 70 provided in any of the above embodiments; their specific structure and technical effects will not be described in detail here. This light-emitting device can be used for all types of lighting.

[0101] In addition to the application scenarios described in the embodiments above, the light-emitting diodes 10 and 70 provided by the present invention can also be used in fields including but not limited to general indoor lighting and automotive applications. The reliability requirements for light-emitting diodes are particularly high in the field of automotive lighting.

[0102] In summary, the present invention provides a light-emitting diode 10, which, through the provision of a first insulating portion 141 and a second insulating portion 142, makes the upper surfaces of the first connecting electrode 21 and the second connecting electrode 22 flush, thereby ensuring that the upper surfaces of the first pad 31 and the second pad 32 are at the same height, resulting in a light-emitting diode 10 with high height consistency.

[0103] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: The epitaxial structure includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked from bottom to top; A via extends downward from a portion of the upper surface of the second semiconductor layer, through the light-emitting layer, to the first semiconductor layer; A first insulating layer covers the epitaxial structure above and around the sidewalls of the epitaxial structure; the first insulating layer includes a second insulating portion located only on a portion of the second semiconductor layer; The first connecting electrode and the second connecting electrode are located on the first insulating layer and are electrically connected to the first semiconductor layer and the second semiconductor layer, respectively. A second insulating layer is located on the first connecting electrode and the second connecting electrode, and has a third opening and a fourth opening; The first pad, located on the second insulating layer, contacts the first connecting electrode through the third opening; The second pad, located on the second insulating layer, contacts the second connection electrode through the fourth opening; The first and second pads are also located on the first insulating layer; The second insulating portion has a plurality of protrusions that protrude toward the first pad; the second connecting electrode has a protrusion with the same shape as the protrusions of the second insulating portion that completely covers the protrusions.

2. The light-emitting diode according to claim 1, characterized in that: The edges of the first pad and the second pad are both located on the upper surface of the second insulating layer. When viewed from above the light-emitting diode toward the epitaxial structure, there is a fourth distance between the edge of the first pad and the edge of the third opening, which is between 5 and 20 micrometers. There is a fifth distance between the edge of the second pad and the edge of the fourth opening, which is between 5 and 20 micrometers.

3. The light-emitting diode according to claim 1, characterized in that: The horizontal projected area of ​​the second pad is greater than 100% and less than or equal to 110% of the horizontal projected area of ​​the fourth opening; the horizontal projected area of ​​the first pad is greater than 100% and less than or equal to 110% of the horizontal projected area of ​​the third opening.

4. The light-emitting diode according to claim 1, characterized in that: The thickness of the first insulating layer is 0.8 micrometers to 1.5 micrometers.

5. The light-emitting diode according to claim 1, characterized in that: Viewed from above the light-emitting diode toward the epitaxial structure, the first connecting electrode extends to the bottom of the via and connects to the first semiconductor layer, while the second connecting electrode and the second pad both avoid the via.

6. The light-emitting diode according to claim 1, characterized in that: The horizontal projected area of ​​the second pad accounts for more than 90% and less than or equal to 100% of the horizontal projected area of ​​the second connecting electrode.

7. The light-emitting diode according to claim 1, characterized in that: Viewed from above the light-emitting diode toward the epitaxial structure, there is a second distance between the edge of the second connecting electrode and the edge of the second pad, the second distance being between 15 and 50 micrometers.

8. The light-emitting diode according to claim 1, characterized in that: Viewed from above the light-emitting diode toward the epitaxial structure, there is a third distance between the first connecting electrode and the second connecting electrode, the third distance being 10 to 30 micrometers.

9. The light-emitting diode according to claim 1, characterized in that: The light-emitting diode further includes a reflective layer and a blocking layer. The reflective layer is disposed on the second semiconductor layer, and the blocking layer covers the reflective layer. The horizontal projected area of ​​the reflective layer accounts for at least 80% of the horizontal projected area of ​​the second semiconductor layer.

10. The light-emitting diode according to claim 1, characterized in that: The first insulating layer includes a second opening, through which the second connecting electrode is electrically connected to the second semiconductor layer.

11. The light-emitting diode according to claim 10, characterized in that: Viewed from above the light-emitting diode toward the epitaxial structure, the fourth opening of the second insulating layer does not overlap with the second opening of the first insulating layer.

12. The light-emitting diode according to claim 10, characterized in that: Viewed from above the light-emitting diode toward the epitaxial structure, the second pad does not overlap with the second opening of the first insulating layer.

13. The light-emitting diode according to claim 1, characterized in that: The length or width of the light-emitting diode is between 500 micrometers and 2000 micrometers, and the length-to-width ratio of the light-emitting diode is between 1:1 and 2:

1.

14. A light-emitting device, characterized in that, The light-emitting diode used is as described in any one of claims 1 to 13.

15. The light-emitting device according to claim 14, characterized in that: The light-emitting device is a light-emitting device used for illumination.

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