Light emitting diode and method of manufacturing the same, light emitting device

Abstract

The application belongs to the technical field of semiconductor, and particularly relates to a light emitting diode, a manufacturing method thereof and a light emitting device. The light emitting diode comprises a substrate, the side surface of the substrate has a cutting surface; an LED chip is located on the substrate, the LED chip has a long side and a short side, wherein the cutting surface corresponding to the long side of the LED chip is a first cutting surface, and the cutting surface corresponding to the short side of the LED chip is a second cutting surface; in the vertical direction, the height h1 of the first cutting surface is different from the height h2 of the second cutting surface. The application can improve the ability of side reflection, so that more light can be emitted from the front, thereby improving the light emitting efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a light-emitting diode, its manufacturing method, and a light-emitting device. Background Technology

[0002] Currently, light-emitting diodes (LEDs) are widely used in lighting and display fields due to their advantages such as high efficiency, long lifespan, all-solid-state operation, self-emissive nature, and environmental friendliness. Gallium nitride (GaN) LEDs, in particular, have become a key research focus for industry, academia, and research institutions both domestically and internationally due to their bandgap covering various colors of light, and significant progress has been made in epitaxy and chip technology. However, LEDs still suffer from relatively low luminous efficiency, partly due to limitations in the light-emitting area and efficiency of the LEDs. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a light-emitting diode and its manufacturing method and light-emitting device, so as to improve the light emission efficiency of the light-emitting diode.

[0004] To achieve the above objectives, according to a first aspect of the present invention, a light-emitting diode is provided, comprising: a substrate having a cross-section on its side surface; an LED chip located on the substrate, the LED chip having a long side and a short side, wherein the cross-section of the substrate below the long side of the LED chip is a first cross-section, and the cross-section of the substrate below the short side of the LED chip is a second cross-section; in the vertical direction, the height h1 of the first cross-section is different from the height h2 of the second cross-section.

[0005] Preferably, the cut surface is located on the top side of the substrate.

[0006] Preferably, the surfaces of the first and / or second cut surfaces are rough.

[0007] Preferably, the surface of the first and / or second cut surfaces has a plurality of transverse stripes.

[0008] Preferably, the height h1 of the first cut surface is greater than the height h2 of the second cut surface.

[0009] Preferably, the height h1 of the first cut surface is greater than 7 μm, and the height h2 of the second cut surface is 5~7 μm.

[0010] Preferably, the angle between the first tangent and the horizontal direction is θ1, and the angle between the second tangent and the horizontal direction is θ2, wherein 60° < θ1 < 90°, and 60° < θ2 < 90°.

[0011] Preferably, the included angles θ1 and θ2 are the same or different.

[0012] According to a second aspect of the present invention, a light-emitting device is provided, which employs a light-emitting diode as described above.

[0013] According to a third aspect of the present invention, a method for manufacturing a light-emitting diode is provided, characterized by comprising the steps of: S1. Provide a raw substrate and grow an epitaxial layer on the raw substrate; S2. Etch the epitaxial layer to form a plurality of LED chips, and define the long side and short side of the LED chips; S3. The first laser scribing is used to scribing from the long side of the LED chip into the original substrate, creating the first V-groove. S4. A second laser scribing is used to scribing from the short side of the LED chip into the original substrate, creating a second V-groove. The depth of the second V-groove is different from the depth of the first V-groove. S5. Thin the original substrate and separate the LED chip along the V-groove to form an independent light-emitting diode with a substrate. The side of the substrate is formed with a cross-section. The cross-section of the substrate below the long side of the LED chip is the first cross-section, and the cross-section of the substrate below the short side of the LED chip is the second cross-section. In the vertical direction, the height h1 of the first cross-section is different from the height h2 of the second cross-section.

[0014] Preferably, a protective layer is deposited on the surface of the LED chip before each laser scribing.

[0015] Preferably, after each laser scribing, an etching process is first used to remove the slag generated during laser scribing, and then the protective layer on the surface of the LED chip is removed.

[0016] Preferably, the depth of the first V-groove is greater than the depth of the second V-groove.

[0017] Preferably, the depth of the first V-groove is greater than 7 μm, and the depth of the second V-groove is 5~7 μm.

[0018] Preferably, the etching time for the long side of the LED chip is shorter than the etching time for the short side of the LED chip.

[0019] Preferably, a plurality of transverse stripes are formed on the inner wall of the first V-groove and / or the second V-groove by laser scribing.

[0020] Preferably, the etching process employs wet etching.

[0021] Compared with the prior art, the light-emitting diode, light-emitting device, and method for preparing the light-emitting diode described in this invention have at least the following beneficial effects: This invention is applicable to light-emitting diodes (LEDs) with long and short sides. Structurally, by forming a cross-section on the side of the substrate, the side area of ​​the LED is increased, thereby improving the side reflection capability and allowing more light to be emitted from the front. Specifically, the substrate cross-section below the long side of the LED chip is the first cross-section, and the substrate cross-section below the short side of the LED chip is the second cross-section. Vertically, the heights h1 and h2 of the first and second cross-sections are different, effectively increasing the coverage area of ​​the light emitted from the front, thus improving the light extraction efficiency. In terms of manufacturing process, during the separation into individual LEDs, this invention employs a step-by-step processing method for the long and short sides of the LED chip, rather than the simultaneous processing of the long and short sides in existing technologies. This facilitates better removal of slag and effectively avoids subsequent over-etching defects, ensuring the brightness of the LED.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0023] Figure 1 The diagram shows a cross-sectional view of the original substrate.

[0024] Figure 2 The diagram shows a cross-sectional structure of an epitaxial layer grown on a pristine substrate.

[0025] Figures 3-4 The diagram shows a cross-sectional structure of an LED chip (long and short sides) after the epitaxial layer has been etched.

[0026] Figure 5 The diagram shows the cross-sectional structure after the first laser scribing.

[0027] Figure 6 The image shows a cross-sectional view after the second laser scribing.

[0028] Figure 7 The diagram shows a cross-sectional structure after the deposition of the first protective layer.

[0029] Figure 8 The diagram shows a cross-sectional structure after the deposition of the second protective layer.

[0030] Figures 9-10 The diagram shows a cross-sectional view of the electrode structure after fabrication.

[0031] Figure 11 The diagram shown is a top view of the structure of a light-emitting diode.

[0032] Figures 12-13 The diagram shows a cross-sectional view of a light-emitting diode.

[0033] Figure 14 The diagram shows a cross-section of a light-emitting diode.

[0034] Figure label: 1. Original substrate; 2. Epitaxial layer; 21. First semiconductor layer; 22. Active layer; 23. Second semiconductor layer; 24. Isolation trench; 25. Step structure; 251. Lower step surface; 252. Upper step surface; 3. V-groove; 31. First V-groove; 32. Second V-groove; 4. Protective layer; 41. First protective layer; 42. Second protective layer; 5. Electrode structure; 51. First electrode; 52. Second electrode; 6. Laser scribing machine; 10. Substrate; 101. Cross-section; 1011. First cross-section; 1012. Second cross-section; 20. LED chip; 201. Long side; 202. Short side; 30. Horizontal stripe. Implementation

[0035] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention. Example 1

[0036] This embodiment provides a method for manufacturing a light-emitting diode (LED), the method comprising the following steps: Step S1: Provide a raw substrate 1, and grow an epitaxial layer 2 on the raw substrate 1, such as... Figures 1-2 As shown; Specifically, the original substrate 1 can be an insulating substrate or a conductive substrate. The substrate material is selected from Al2O3, SiC, GaAs, GaN, AlN, GaP, Si, ZnO, MnO, and any combination thereof. In this embodiment, the original substrate 1 is preferably a sapphire (Al2O3) substrate.

[0037] In this embodiment, an epitaxial layer 2 is grown on a pristine substrate 1. The epitaxial layer 2 can be formed on the pristine substrate 1 using methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and epitaxial growth. The epitaxial layer 2 includes at least a first semiconductor layer 21, an active layer 22, and a second semiconductor layer 23 sequentially formed on the upper surface of the pristine substrate 1. The conductivity type of the second semiconductor layer 23 is opposite to that of the first semiconductor layer 21; for example, the first semiconductor layer 21 can be an n-type semiconductor, and the second semiconductor layer 22 can be a p-type semiconductor. The active layer 22 is the quantum well region used for light emission, and the active layer 22 can emit red, green, blue, or other types of light.

[0038] Next, step S2 is performed to etch the epitaxial layer 2, forming a plurality of LED chips 20, defining the long side 201 and short side 202 of the LED chip 20, as follows: Figures 3-4 As shown; According to actual production needs, isolation trenches 24 and step structures 25 are formed by etching the epitaxial layer 2. The isolation trenches 24 isolate the epitaxial layer 2 to form a plurality of independent LED chips 20. The LED chip 20 (light-emitting diode) finally obtained in this embodiment has long and short sides. The long side 201 and short side 202 of the LED chip 20 are defined by comparing the side lengths of the LED chip 20.

[0039] Specifically, each LED chip 20 includes at least an epitaxial layer 2 with a stepped structure 25, also known as MESA, which is a common structure in light-emitting diodes. Its function is to facilitate the subsequent fabrication of the electrode structure 5. The stepped structure 25 includes a lower stepped surface 251 and an upper stepped surface 252. The lower stepped surface 252 is the upper surface of the first semiconductor layer 21 exposed by etching, and the upper stepped surface 252 is the upper surface of the second semiconductor layer 23.

[0040] Next, step S3 is performed, using a first laser scribing technique to scribe the LED chip 20 from its long side 201 into the original substrate 1, creating a first V-groove 31, as shown below. Figure 5 As shown; Specifically, in the isolation trench 24 between adjacent LED chips 20, a laser scribing machine 6 performs a first laser scribing along the long side 201 of the LED chip 20. The first laser scribing extends from the upper surface of the original substrate 1 into the interior of the substrate to form a first V-groove 31. The depth of this first laser scribing is the depth of the first V-groove 31. It should be noted that the inner wall of the first V-groove 31 will become a cross-section 101 of the substrate after the subsequent separation of the light-emitting diodes.

[0041] Regarding laser scribing, a laser scribing machine 6 emits laser pulses of a specific power, wavelength, and focal length at a specific frequency onto the original substrate 1, forming a V-groove 3 by focusing the laser onto the original substrate 1. The frequency and power of the laser are not limited during the laser scribing process and are determined based on the actual situation. In this embodiment, the laser processing speed is kept constant; when creating deeper V-grooves 3, this can be achieved by increasing the laser processing power.

[0042] Because laser scribing can easily damage the LED chip 20, and also generates debris and slag in the scribing area of ​​the original substrate 1, the slag can absorb the light emitted by the LED chip 20, thus affecting the light emission efficiency of the light-emitting diode. To avoid damage to the LED chip 20, this embodiment further includes depositing a first protective layer 41 on the surface of the LED chip 20 before the first laser scribing, such as... Figure 7 As shown. The first protective layer 41 effectively protects the LED chip 20 to prevent damage to the LED chip 20 during subsequent operations. The specific material can be selected from silicon dioxide or silicon nitride. Due to the setting of the first protective layer 41, the first laser scribing will extend from the first protective layer 41 into the interior of the original substrate 1. At this time, the scribing depth of the first laser scribing is greater than the depth of the first V-groove 31. It should be noted that the depth of all V-grooves 3 mentioned in this invention refers to the distance from the bottom of the V-groove 3 to the upper surface of the original substrate 1.

[0043] To improve the light absorption defect of molten slag, this embodiment further includes: after the first laser scribing, a first etching process is used to remove the molten slag generated during the first laser scribing. The first etching process may include dry etching, wet etching, or a combination of both. Wet etching is preferred; specifically, a mixed solution of phosphoric acid and sulfuric acid is used for wet etching. The first etching process effectively removes the molten slag, exposing the inner wall of the first V-groove 31, allowing light incident on this area to be effectively emitted, thereby increasing the light emission range and improving the light extraction efficiency. After the first etching process, the remaining first protective layer 41 on the surface of the LED chip 20 needs to be removed. With the removal of the first protective layer 41, residual debris and molten slag carried on its surface are also removed, further preventing impurities from absorbing light and improving the light extraction efficiency. Specifically, a solution containing hydrogen fluoride is preferably used to remove the first protective layer 41.

[0044] Next, in step S4, a second laser scribing is performed to scribe the LED chip 20 from its short side 202 into the original substrate 1, creating a second V-groove 32. The depth of the second V-groove 32 is different from the depth of the first V-groove 31. Figure 6 As shown; Specifically, in the isolation trench 24 between adjacent LED chips 20, a laser scribing machine 6 performs a second laser scribing along the short side 202 of the LED chip 20. This second laser scribing also extends from the upper surface of the original substrate 1 into the interior of the substrate, forming a second V-groove 32. The depth of this second laser scribing is the depth of the second V-groove 32. It should be noted that the inner wall of the second V-groove 32 will become another cut surface 101 of the substrate 10 after the subsequent separation of the light-emitting diodes.

[0045] This embodiment requires that the depth of the second V-groove 32 be different from the depth of the first V-groove 31, thereby effectively improving the light emission coverage and increasing luminous efficiency. Experiments have verified that when the depth of the first V-groove 31 is greater than the depth of the second V-groove 32, the light-emitting diode with this structure exhibits higher light emission efficiency. The depth of the second V-groove 32 can be a conventional depth, typically not exceeding 7 μm, preferably 5~7 μm, while the first V-groove 31 has a deeper depth, exceeding 7 μm. By limiting the depths of the first V-groove 31 and the second V-groove 32, a better light emission effect and increased luminous brightness can be achieved.

[0046] By deepening the first V-groove 31, the area of ​​its inner wall can be effectively increased, thereby improving the light reflection effect of the light-emitting diode. In addition, it also facilitates the formation of a rough surface on the inner wall of the first V-groove 31, further improving the light extraction efficiency of the light-emitting diode. In the prior art, the laser scribing depth is relatively shallow, and sufficient oxygen is provided during scribing, resulting in high scribing efficiency and fast melting speed, leading to a smooth inner wall of the final V-groove 3. However, this embodiment deepens the first laser scribing without providing additional oxygen, resulting in lower laser scribing efficiency and slower melting speed. This makes it easier to form disordered transverse stripes 30 on the inner wall of the first V-groove 31, giving it high roughness, which is beneficial for improving light extraction efficiency. Regarding the inner wall of the second V-groove 32, a rough surface can also be formed, creating disordered transverse stripes 30. For example, this can be achieved by controlling and reducing the processing power and speed of the laser scribing machine 6, and extending the laser scribing operation time, but the methods are not limited to this. The method in this embodiment does not require additional process steps; it can be achieved by adjusting the process parameters of the relevant processes. Therefore, it does not increase costs and is beneficial for mass production.

[0047] Similarly, to avoid damage to the LED chip 20 and the residue of molten slag, this embodiment further includes: depositing a second protective layer 42 on the surface of the LED chip 20 before performing the second laser scribing, such as... Figure 8As shown. The material of the second protective layer 42 can be the same as or different from the material of the first protective layer 41. Due to the provision of the second protective layer 42, the second laser scribing will extend from the second protective layer 42 into the interior of the original substrate 1. At this time, the scribing depth of the second laser scribing is greater than the depth of the second V-groove 32. It should be noted that the depth of all V-grooves 3 mentioned in this invention refers to the distance from the bottom of the V-groove 3 to the upper surface of the original substrate 1.

[0048] This embodiment also includes: after the second laser scribing, a second etching process is used to remove the slag generated during the second laser scribing. The second etching process can be the same as or different from the first etching process, and preferably a wet etching process the same as the first etching process is used. Taking the depth of the first V-groove 31 as an example that is greater than the depth of the second V-groove 32, the etching time for the first etching process (etching the long side 201) of the LED chip 20 should be shorter than the etching time for the second etching process (etching the short side 202) of the LED chip 20, thereby avoiding over-etching abnormalities on the long side of the LED chip 20. In addition, after the second etching process is completed, the remaining second protective layer 42 on the surface of the LED chip 20 needs to be removed. The removal method of the second protective layer 42 can refer to the removal method of the first protective layer 41.

[0049] This embodiment employs a step-by-step processing method for the long and short sides of the LED chip 20, rather than the simultaneous processing method used in the prior art. Because the depth of the second V-groove 32 differs from the depth of the first V-groove 31, an etching process is required after each laser scribing operation to correct over-etching on one side. Since the depths of the first V-groove 31 and the second V-groove 32 differ, the amount of slag adhering to their inner walls also differs, requiring different etching times to remove the slag. While using two consecutive etching processes (effectively extending the etching time) can better remove slag, it easily leads to over-etching defects on either the long side 201 or the short side 202, thus affecting the brightness of the LED.

[0050] Next, step S5 is performed: the original substrate 1 is thinned and the LED chip 20 is separated along the V-groove 3 to form an independent light-emitting diode with substrate 10, as shown below. Figure 6 As shown; Because the original substrate 1 is relatively thick, it is not conducive to separating it into individual light-emitting diodes. Therefore, it is usually necessary to use thinning processes such as grinding to thin the original substrate 1, and then use the V-groove 3 to separate them through a dicing process. In this embodiment, the dicing process can be achieved by splitting, for example, by back-splitting. The specific process of back-splitting is well known to those skilled in the art and will not be described in detail here. In other embodiments, the substrate 10 can also be split along the position of the V-groove 3 by film expansion to form multiple light-emitting diodes.

[0051] More specifically, multiple light-emitting diodes with substrate 10 are formed by separating along the first V-groove 31 and the second V-groove 32. Due to the separation of the V-groove 3, the inner wall of the V-groove 3 is formed as a cross-section 101 of the side surface of the substrate 10. Among them, the cross-section 101 of the substrate 10 below the long side 201 of the LED chip 20 is the first cross-section 1011, and the cross-section 101 of the substrate 10 below the short side 202 of the LED chip 20 is the second cross-section 1012. Since the depth of the first V-groove 31 is different from the depth of the second V-groove 32, the height h1 of the first cross-section 1011 and the height h2 of the second cross-section 1012 are also different in the vertical direction.

[0052] Before being separated into individual light-emitting diodes, each LED chip 20 further includes an electrode structure 5, which can be formed by vapor deposition. In this embodiment, the electrode structure 5 includes a first electrode 51 and a second electrode 52, wherein the first electrode 51 is formed on the lower step surface 251 and electrically connected to the first semiconductor layer 21, and the second electrode 52 is formed on the upper step surface 252 and electrically connected to the second semiconductor layer 23, as shown below. Figures 9-10 As shown. Example 2

[0053] This embodiment provides a light-emitting diode, such as Figures 11-13 As shown, the light-emitting diode can be manufactured by the method in Embodiment 1 above, but is not limited to the method in Embodiment 1. The light-emitting diode specifically includes: a substrate 10 and an LED chip 20 located on the substrate 10, wherein the side of the substrate 10 has a cross-section 101, and the LED chip 20 has a long side 201 and a short side 202.

[0054] Specifically, the substrate 10 has a cross-section 101 on each of its four sides, while the LED chip 20 has two long sides 201 and two short sides 202. The cross-section of the substrate 10 below the long side 201 of the LED chip 20 is the first cross-section 1011, and the cross-section of the substrate 10 below the short side 202 of the LED chip 20 is the second cross-section 1012. In other embodiments, the surface area, height, and slope of the two first cross-sections 1011 may be different, and the surface area, height, and slope of the two second cross-sections 1012 may also be different.

[0055] The cut surface 101 is located on the top side of the substrate 10. It is an outwardly sloping surface formed by the inner wall of the V-groove 3 after separation. Since the depths of the first V-groove 31 and the second V-groove 32 are different, the height h1 of the first cut surface 1011 and the height h2 of the second cut surface 1012 are different in the vertical direction.

[0056] Preferably, in the vertical direction, the height h1 of the first cut surface 1011 is greater than the height h2 of the second cut surface 1012. More preferably, the height h1 of the first cut surface 1011 is greater than 7 μm, and the height h2 of the second cut surface 1012 is 5~7 μm. By increasing the side surface area of ​​the light-emitting diode, the side reflection is improved, the refracted light is reduced, and more light can be emitted from the front of the light-emitting diode, thereby improving the light extraction efficiency of the light-emitting diode.

[0057] More preferably, the surfaces of the first cut surface 1011 and / or the second cut surface 1012 are roughened, which can further improve the light reflection capability of the sides. Preferably, the surfaces of the first cut surface 1011 and / or the second cut surface 1012 have a plurality of transverse stripes 30, which cover all areas of the cut surface 101, such as... Figure 14 As shown. The transverse stripe 30 can be produced without the need for other processes, and can be achieved by controlling the laser scribing process, which shortens the process and saves costs. Of course, it is not excluded that other processes can achieve the above structure, and this application does not make any special limitations.

[0058] More specifically, the angle between the first cut surface 1011 and the horizontal direction is θ1, and the angle between the second cut surface 1012 and the horizontal direction is θ2, wherein 0° < θ1 < 90°, 0° < θ2 < 90°. For example, the angles θ1 and θ2 can be 10°, 20°, 30°, 40°, 50°, 60°, 70°, or 80°, but are not limited to the angles mentioned above. More preferably, 60° < θ1 < 90°, 60° < θ2 < 90°. In embodiments of the present invention, the angles θ1 and θ2 may be the same or different. At the same angle, the greater the height of the vertical cut surface 101, the larger the substrate cross-sectional area of ​​the light-emitting diode, which improves the reflectivity of the cut surface 101 and the higher the light extraction efficiency of the light-emitting diode. At the same height, the smaller the angle between the cut surface 101 and the horizontal plane, the more inclined the sidewall of the substrate 10 becomes, resulting in a larger substrate cut surface area for the light-emitting diode, which further enhances the reflectivity of the cut surface 101 and increases the light extraction efficiency of the light-emitting diode. In other embodiments, the angles formed by the two first cut surfaces 1011 in the horizontal direction may be different, or the angles formed by the two second cut surfaces 1012 with the horizontal direction may also be different.

[0059] The LED chip 20 is obtained by separating the initial epitaxial layer 2 and the original substrate 1. The LED chip 20 includes at least the epitaxial layer 2 and the electrode structure 5 located on the epitaxial layer 2. The epitaxial layer 2 includes at least a first semiconductor layer 21, an active layer 22, and a second semiconductor layer 23 sequentially formed on the upper surface of the substrate 10. In other embodiments, the epitaxial layer 2 may also include other layer materials, such as a buffer layer, a current blocking layer, a transparent conductive layer, or an ohmic contact layer, which can be configured according to actual conditions. The above-mentioned layer structures are well known to those skilled in the art and will not be described in detail here.

[0060] The electrode structure 5 includes a first electrode 51 and a second electrode 52, wherein the first electrode 51 is located on the lower step surface 251 and electrically connected to the first semiconductor layer 21, and the second electrode 52 is located on the upper step surface 252 and electrically connected to the second semiconductor layer 23.

[0061] Specifically, both the first electrode 51 and the second electrode 52 are metallic electrodes. The materials of the second electrode 52 and the first electrode 51 are selected from one or more combinations of a group consisting of nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), gold (Au), titanium (Ti), silver (Ag), aluminum (Al), germanium (Ge), tungsten (W), tungsten silicide (SiW), tantalum (Ta), gold-zinc alloy (AuZn), gold-beryllium alloy (AuBe), gold-germanium alloy (AuGe), and gold-germanium-nickel alloy (AuGeNi). Typically, the first electrode 51 and the second electrode 52 are formed by depositing layers of multiple metallic materials.

[0062] Comparative experiments between existing technologies and the light-emitting diodes of this invention revealed that the light-emitting diode of this invention has a significantly improved light extraction efficiency, as detailed below:

[0063] Table 1. Spot test data of LEDs

[0064] Table 2. Light-emitting diode lamp packing data Referring to Tables 1 and 2, under the same test conditions, the present invention improves the brightness by 1.87% under spot testing compared to the prior art, while reducing the brightness by 0.85% under full-coverage testing. Overall, the luminous efficiency of the light-emitting diode of the present invention is improved by 1.02% compared to the prior art. Example 3

[0065] This embodiment also provides a light-emitting device, including the light-emitting diode provided in the above embodiments. The light-emitting device can be, for example, a white light illumination device, a backlight display device, a vehicle headlight, a flashlight, a projection lamp, a stage light, etc. This light-emitting device features higher light extraction efficiency and luminous brightness.

[0066] Compared with the prior art, the light-emitting diode, light-emitting device, and method for preparing the light-emitting diode described in this invention have at least the following beneficial effects: This invention is applicable to light-emitting diodes (LEDs) with long and short sides. Structurally, a cross-section 101 is formed on the side of the substrate 10 to increase the side area of ​​the LED, thereby improving the side reflection capability and allowing more light to be emitted from the front. Specifically, the substrate cross-section below the long side 201 of the LED chip 20 is the first cross-section 1011, and the substrate cross-section below the short side 202 of the LED chip 20 is the second cross-section 1012. Vertically, the height h1 of the first cross-section 1011 differs from the height h2 of the second cross-section 1012, effectively increasing the coverage area of ​​the light emitted from the front and thus improving the light extraction efficiency. In terms of manufacturing process, during the separation into independent LEDs, this invention employs a step-by-step processing method for the long and short sides of the LED chip 20, rather than the simultaneous processing of the long and short sides in the prior art. This facilitates better removal of slag and effectively avoids subsequent over-etching defects, ensuring the brightness of the LED.

[0067] However, the above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art to which this invention pertains can make modifications and variations to the above embodiments without departing from the technical principles and spirit of the present invention. Therefore, the scope of protection of this invention should be as set forth in the appended claims.

Claims

1. A light-emitting diode, characterized in that, include: A substrate, wherein the side surface of the substrate has a cross-section; An LED chip is located on the substrate, and the LED chip has a long side and a short side, wherein... The substrate cross-section below the long side of the LED chip is the first cross-section, and the substrate cross-section below the short side of the LED chip is the second cross-section. In the vertical direction, the height h1 of the first cross-section is different from the height h2 of the second cross-section. The height h1 of the first cross-section is greater than the height h2 of the second cross-section, and the height h1 of the first cross-section is greater than 7μm.

2. The light-emitting diode according to claim 1, characterized in that, The first cut surface and / or the second cut surface are located on the top side of the substrate.

3. The light-emitting diode according to claim 1 or 2, characterized in that, The surfaces of the first and / or second cut surfaces are rough.

4. The light-emitting diode according to claim 3, characterized in that, The surface of the first and / or second cut surfaces has a plurality of transverse stripes.

5. The light-emitting diode according to claim 1, characterized in that, The height h2 of the second cut surface is 5~7μm.

6. The light-emitting diode according to claim 1, characterized in that, The first tangent plane makes an angle of θ1 with the horizontal direction, and the second tangent plane makes an angle of θ2 with the horizontal direction, wherein 60° < θ1 < 90° and 60° < θ2 < 90°.

7. The light-emitting diode according to claim 6, characterized in that, The included angles θ1 and θ2 may be the same or different.

8. A light-emitting device, characterized in that: The light-emitting diode described in any one of claims 1 to 7 is used.

9. A method for manufacturing a light-emitting diode, characterized in that, Including the following steps: S1. Provide a raw substrate and grow an epitaxial layer on the raw substrate; S2. Etch the epitaxial layer to form a plurality of LED chips, and define the long side and short side of the LED chips; S3. The first laser scribing is used to scribble from the long side of the LED chip into the original substrate, creating the first V-groove. S4. A second laser scribing is used to scribing from the short side of the LED chip into the original substrate, creating a second V-groove. The depth of the second V-groove is different from the depth of the first V-groove. S5. Thin the original substrate and separate the LED chip along the V-groove to form an independent light-emitting diode with a substrate. The side of the substrate is formed with a cross-section. The cross-section of the substrate below the long side of the LED chip is the first cross-section, and the cross-section of the substrate below the short side of the LED chip is the second cross-section. In the vertical direction, the height h1 of the first cross-section is different from the height h2 of the second cross-section. The height h1 of the first cross-section is greater than the height h2 of the second cross-section. The height h1 of the first cross-section is greater than 7 μm.

10. The method for manufacturing a light-emitting diode according to claim 9, characterized in that, Before each laser scribing, a protective layer is deposited on the surface of the LED chip.

11. The method for manufacturing a light-emitting diode according to claim 9, characterized in that, After each laser scribing, an etching process is first used to remove the slag generated during laser scribing, and then the protective layer on the surface of the LED chip is removed.

12. The method for manufacturing a light-emitting diode according to claim 9, characterized in that, The depth of the first V-groove is greater than the depth of the second V-groove.

13. The method for manufacturing a light-emitting diode according to claim 9 or 12, characterized in that, The depth of the first V-groove is greater than 7 μm, and the depth of the second V-groove is 5~7 μm.

14. The method for manufacturing a light-emitting diode according to claim 11, characterized in that, The etching time for the long side of the LED chip is shorter than the etching time for the short side of the LED chip.

15. The method for manufacturing a light-emitting diode according to claim 9, characterized in that, Multiple transverse stripes are formed on the inner wall of the first V-groove and / or the second V-groove using a laser scribing process.

16. The method for manufacturing a light-emitting diode according to claim 11, characterized in that, The etching process employs wet etching.

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