Semiconductor light emitting diode and preparation method thereof

Abstract

A semiconductor light-emitting diode and a method for manufacturing the same. The semiconductor light-emitting diode comprises a semiconductor light-emitting stack located on a substrate, a transparent conductive layer located on the semiconductor light-emitting stack, and a reflective layer located on the transparent conductive layer. The semiconductor light-emitting diode also comprises an insulating structure located at least partially on the transparent conductive layer, having an oblique side surface that surrounds the edge of the upper surface of the transparent conductive layer, and a side surface of the reflective layer that covers the oblique side surface of the insulating structure. The reflective layer within the semiconductor light-emitting diode is less susceptible to peeling.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor solid-state lighting, and in particular to a semiconductor light emitting diode and a preparation method thereof. Background Art

[0002] Commercial semiconductor light-emitting diode (LED) packaging initially employed a forward-mounted packaging structure, with gold wires connecting the chip's PN junction to the positive and negative terminals of the housing. However, this forward-mounted structure suffered from issues such as significant light decay, light quenching, and heat dissipation, hindering its development. Consequently, industry researchers subsequently developed vertical and flip-chip semiconductor LEDs.

[0003] Compared to upright semiconductor light-emitting diodes, a vertical semiconductor light-emitting diode structure improves heat dissipation efficiency. In a vertical semiconductor light-emitting diode, two electrodes are located on either side of the semiconductor light-emitting diode epitaxial layer. This allows current to flow almost entirely vertically through the semiconductor light-emitting diode epitaxial layer, with minimal current flowing laterally, thus preventing localized high temperatures.

[0004] Compared to upright-mounted semiconductor light-emitting diodes, flip-chip semiconductor light-emitting diodes (LEDs) offer integrated and mass-produced structures, simple manufacturing processes, and superior performance. The flip-chip structure utilizes eutectic bonding of the semiconductor LED's PN junction directly to the positive and negative electrodes on the substrate, eliminating the need for gold wires and minimizing light quenching. This eutectic bonding significantly improves heat dissipation.

[0005] However, both the vertically packaged semiconductor light emitting diode structure and the flip-chip semiconductor light emitting diode structure have the problem of easy peeling of the internal reflective layer, which still needs to be improved. Summary of the Invention

[0006] The problem solved by the present invention is to provide a semiconductor light emitting diode and a preparation method thereof, so that the problem of easy peeling and poor coverage of the internal reflective layer of the semiconductor light emitting diode is improved, and the performance is improved.

[0007] To solve the above problems, the present invention provides a semiconductor light-emitting diode, comprising a semiconductor light-emitting stack located on a substrate, the semiconductor light-emitting stack having a transparent conductive layer thereon, the transparent conductive layer having a reflective layer thereon, and an insulating structure, the insulating structure being at least partially located on the transparent conductive layer, the insulating structure having an oblique side surface, the oblique side surface of the insulating structure surrounding the edge of the upper surface of the transparent conductive layer, and the side surface of the reflective layer covering the oblique side surface of the insulating structure; and further comprising an insulating block connected to the insulating structure, the insulating block having a plurality of through holes, the reflective layer covering the insulating block, and the reflective layer and the insulating block forming an omnidirectional reflector structure on the transparent conductive layer.

[0008] Optionally, the bottom surface of the insulating structure covers a portion of the upper surface of the semiconductor light-emitting stack and a portion of the upper surface of the transparent conductive layer.

[0009] Optionally, the thickness of the insulating block is smaller than the maximum thickness of the insulating structure on the transparent conductive layer, and the thickness of the reflective layer is larger than the thickness of the insulating block.

[0010] Optionally, the thickness of the insulating block is less than half of the maximum thickness of the insulating structure on the transparent conductive layer.

[0011] Optionally, the thickness of the reflective layer is less than or equal to the maximum thickness of the insulating structure on the transparent conductive layer.

[0012] Optionally, a protective layer is provided on the reflective layer, and at least a portion of the side surfaces of the protective layer covers the oblique side surfaces of the insulating structure, so that the angle between the bottom surface and the side surfaces of the protective layer is an obtuse angle.

[0013] Optionally, adjacent semiconductor light-emitting stacks have holes, and the insulating structure also covers the sidewalls and bottom of the holes.

[0014] To solve the above problems, the present invention also provides a method for preparing a semiconductor light-emitting diode, comprising: forming a semiconductor light-emitting stack on a substrate; forming a transparent conductive layer on the semiconductor light-emitting stack; forming an insulating structure and an insulating block connected to the insulating structure, wherein the insulating structure is at least partially formed on the transparent conductive layer, the insulating structure has an oblique side surface, the oblique side surface of the insulating structure surrounds the edge of the upper surface of the transparent conductive layer, the insulating block has a plurality of through holes, the emitting layer covers the insulating block, the reflective layer and the insulating block form an omnidirectional reflector structure on the transparent conductive layer; forming a reflective layer on the transparent conductive layer, the reflective layer is located in the area surrounded by the oblique side surface, and the side surface of the reflective layer covers the oblique side surface of the insulating structure.

[0015] Optionally, the process of forming the insulating structure includes: forming an insulating material layer to cover the semiconductor light-emitting stack and the transparent conductive layer; forming a patterned primary mask structure on the insulating material layer; etching the insulating material layer using the primary mask structure as a mask to form an insulating layer having an opening; using the insulating layer located on both the upper surface of the semiconductor light-emitting stack and the upper surface of the transparent conductive layer as a first insulating layer, and forming a secondary mask structure on the first insulating layer to at least partially expose the upper surface of the first insulating layer, wherein the partially exposed upper surface of the first insulating layer is located above an edge of the upper surface of the transparent conductive layer;

[0016] Using the secondary mask structure as a mask, the first insulating layer is etched, and the remaining first insulating layer is etched into the insulating structure having the oblique side surface; the process of forming the insulating structure also includes: after forming the semiconductor light-emitting stack, forming a hole groove in the semiconductor light-emitting stack; the first insulating layer simultaneously covers the bottom and side wall of the corresponding hole groove; in the top view direction, the oblique side surface of the insulating structure surrounds the hole groove.

[0017] Optionally, it also includes: using the insulating layer located in the non-edge area of ​​the upper surface of the transparent conductive layer as a second insulating layer; while forming the insulating structure, the insulating layer not covering the secondary mask structure is etched to form an insulating block, the insulating block has a through hole, and the insulating block is connected to the insulating structure; when forming the reflective layer, the reflective layer simultaneously covers the insulating block; or, it also includes: after forming the reflective layer, forming a protective layer to cover the reflective layer, and at least part of the side surface of the protective layer covers the oblique side surface of the insulating structure, so that the angle between the bottom surface and the side surface of the protective layer is an obtuse angle.

[0018] Optionally, the secondary mask structure is formed by photoresist.

[0019] To solve the above problems, the present invention also provides another semiconductor light-emitting diode, comprising: a semiconductor light-emitting stack, and a transparent conductive layer located above the semiconductor light-emitting stack, wherein an insulating layer is disposed on the transparent conductive layer, the insulating layer comprising a first region and a second region surrounding the first region, the first region having a first surface, the second region having a second surface, wherein the first surface is lower than the second surface, and a connecting side surface is defined between the first surface and the second surface, and a reflective layer is disposed on the first region of the insulating layer, with an edge of the reflective layer located on the connecting side surface.

[0020] Optionally, the thickness of the insulating layer in the first region is one third to two thirds of the thickness of the insulating layer in the second region.

[0021] Optionally, the thickness of the reflective layer is less than or equal to the thickness of the insulating layer in the second region.

[0022] Optionally, a protective layer is provided on the reflective layer, and at least a portion of the side surfaces of the protective layer covers the connecting side surfaces, so that the angle between the bottom surface and the side surfaces of the protective layer is an obtuse angle.

[0023] In one aspect of the present invention, an insulating structure with sloping side surfaces encloses a spatial region resembling an irregular funnel. When a reflective layer is formed within this spatial region, the perimeter (ends) of the reflective layer are completely surrounded by the insulating structure. The side surfaces of the reflective layer are formed directly on the sloping side surfaces of the insulating structure. This reduces the risk of peeling of the reflective layer, effectively reducing the risk of peeling and improving the reflective layer's coverage.

[0024] Furthermore, the thickness of the reflective layer is set to be smaller than the maximum thickness of the insulating structure on the transparent conductive layer, ensuring that the side surfaces of the reflective layer cover the oblique side surfaces of the insulating structure, thereby better preventing the reflective layer from peeling off and improving the coverage performance of the reflective layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a semiconductor light emitting diode provided by an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 Schematic diagram of the semiconductor light emitting diode structure after electrodes are fabricated;

[0027] Figure 3 yes Figure 2 A perspective schematic diagram of the semiconductor light emitting diode structure shown in the top view direction;

[0028] Figures 4 to 7 For preparation Figure 1 The schematic structural diagram of the semiconductor light emitting diode corresponding to the corresponding steps shown;

[0029] Figure 8 is a schematic structural diagram of a semiconductor light emitting diode provided by another embodiment of the present invention;

[0030] Figure 9 yes Figure 8 Schematic diagram of the semiconductor light emitting diode structure after electrodes are fabricated;

[0031] Figure 10 yes Figure 9 A perspective schematic diagram of the semiconductor light emitting diode structure shown in the top view direction;

[0032] Figures 11 to 12 For preparation Figure 8The schematic structural diagram of the semiconductor light emitting diode corresponding to the corresponding steps shown;

[0033] Figure 13 is a schematic structural diagram of a semiconductor light emitting diode provided by another embodiment of the present invention;

[0034] Figure 14 yes Figure 13 The schematic diagram of the local structure of the semiconductor light emitting diode after the electrodes are made;

[0035] Figure 15 yes Figure 14 A schematic perspective view of a semiconductor light emitting diode structure as viewed from above.

[0036] 100, 300-substrate; 110, 310-first conductive semiconductor layer; 120, 320-quantum well layer; 130, 330-second conductive semiconductor layer; 140, 340-transparent conductive layer; 150a-first insulating layer; 150b-second insulating layer; 151, 153-insulating structure; 152-insulating block; 151s, 153s-oblique side surface; 160-second mask structure; 170, 230, 360-reflective layer; 180, 240, 370-protective layer; 190, 250, 380-passivation layer; 210, 410-first electrode; 220, 420-second electrode; P1-first part; P2-second part; A-first region; B-second region; a-first surface; b-second surface; c-connecting side surface; 351-insulating layer; 352-insulating layer. DETAILED DESCRIPTION

[0037] In existing semiconductor light-emitting diodes, the end of the reflective layer is prone to abnormal curling, leading to peeling problems and poor coverage. To this end, the present invention provides a new semiconductor light-emitting diode and a preparation method thereof to address the corresponding deficiencies.

[0038] For a clearer representation, the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Please refer to Figure 1 An embodiment of the present invention provides a semiconductor light-emitting diode, including a semiconductor light-emitting stack (not labeled) located on a substrate 100. The semiconductor light-emitting stack includes a first-conductivity-type semiconductor layer 110 located on the substrate 100, a quantum well layer 120 located on the first-conductivity-type semiconductor layer 110, and a second-conductivity-type semiconductor layer 130 located on the quantum well layer 120. A transparent conductive layer 140 is located on the semiconductor light-emitting stack, and a reflective layer 170 is located on the transparent conductive layer 140.

[0040] like Figure 1The semiconductor light emitting diode of this embodiment further includes an insulating structure 151, which is at least partially located on the transparent conductive layer 140. The insulating structure 151 has an oblique side surface 151s (marked at Figure 7 , please refer to Figure 7 ), the oblique side surface 151s of the insulating structure 151 surrounds the edge of the upper surface of the transparent conductive layer 140, and the side surface of the reflective layer 170 covers the oblique side surface 151s of the insulating structure 151, so that the angle between the bottom surface and the side surface of the reflective layer 170 is an obtuse angle.

[0041] The angle between the bottom surface and the side surface of the reflective layer 170 is an obtuse angle. In other words, the oblique side surface 151s of the insulating structure 151 (see the following) Figure 7 ) forms an acute angle with the bottom surface of the insulating structure 151 located on the transparent conductive layer 140. This is due to the structure of the oblique side surface 151s itself. The bottom of the insulating structure 151 has different bottom surface portions due to contact with different structures. The bottom surface located on the transparent conductive layer 140 covers the upper surface of the transparent conductive layer 140, and it is this bottom surface portion that forms an acute angle with the oblique side surface 151s.

[0042] Because the side surface of the reflective layer 170 covers the oblique side surface 151s of the insulating structure 151, the side surface of the reflective layer 170 is also inclined, but the angle of inclination is complementary to that of the oblique side surface 151s. In this embodiment, the side surface of the reflective layer 170 is referred to as the inclined side surface. The inclined side surface means that when the bottom surface of the reflective layer 170 is horizontal, the angle between the bottom surface of the reflective layer 170 and the inclined side surface is an obtuse angle.

[0043] In this embodiment, the insulating structure 151 with the sloping side surfaces 151s encloses a spatial region similar to an irregular funnel. When the reflective layer 170 is formed within this spatial region, the perimeter (ends) of the reflective layer 170 are completely surrounded by the insulating structure 151. The side surfaces of the reflective layer 170 directly cover the sloping side surfaces 151s of the insulating structure 151. This makes it less susceptible to peeling from the sloping side surfaces 151s of the insulating structure 151, effectively reducing the risk of peeling of the reflective layer 170 and improving the coverage of the reflective layer 170.

[0044] The cross-sectional shape of the reflective layer 170 is as follows: Figure 1 As shown, it is specifically an inverted trapezoidal structure, and the inclined side surface of the reflective layer 170 corresponds to the inverted hypotenuse of the inverted trapezoidal structure. It is precisely this shape structure that makes the reflective layer 170 less likely to have abnormal end rolling, peeling problems, and poor coverage problems.

[0045] like Figure 1In this embodiment, the bottom surface of the insulating structure 151 covers both a portion of the upper surface of the semiconductor light-emitting stack and a portion of the upper surface of the transparent conductive layer 140. Thus, the insulating structure 151 surrounds the upper surface of the transparent conductive layer 140, thereby ensuring that the primary upper surface area of ​​the transparent conductive layer 140 is used for forming the reflective layer 170.

[0046] like Figure 1 In this embodiment, the surface of the transparent conductive layer 140 further has an insulating block 152 connected to the insulating structure 151 . Figure 1 The insulating structure 151 and the insulating block 152 have corresponding through-hole (not marked), this is because of the cross-section position. If the cross-section does not pass through the corresponding through hole, the corresponding cross-section will show that the insulating structure 151 and the insulating block 152 are connected together.

[0047] Similarly, the insulating block also has multiple through holes inside. Figure 1 However, the entire insulating block is still partially connected. Meanwhile, the reflective layer 170 covers the insulating block 152 and includes a through hole covering the insulating block 152 , thereby forming an omnidirectional reflector structure on the transparent conductive layer 140 with the reflective layer 170 and the insulating block 152 .

[0048] In this embodiment, the thickness of the insulating block 152 is less than the maximum thickness of the insulating structure 151 on the transparent conductive layer 140. Figure 1 Height corresponding to the middle oblique side 151s (not marked).

[0049] In this embodiment, the thickness of the insulating block 152 may preferably be 200 nm to 1200 nm, and more preferably may be 300 nm to 6000 nm.

[0050] In this embodiment, the width of the through hole (not marked) in the insulating block 152 may preferably be 2 μm to 50 μm, and more preferably may be 6 μm to 20 μm, for example, 6 μm, 10 μm, or 20 μm.

[0051] Meanwhile, in this embodiment, the thickness of the reflective layer 170 is greater than the thickness of the insulating block 152. The thickness of the reflective layer 170 is greater than the thickness of the insulating block 152, ensuring that the reflective layer 170 completely covers the insulating block 152, thereby ensuring the formation of an omnidirectional reflector structure.

[0052] It should be noted that in other embodiments, the thickness of the reflective layer may be smaller than the thickness of the insulating block. In this case, the reflective layer may cover the surface (including the upper surface and the bottom and sidewall surfaces of the through-hole) formed on the insulating block (including its through-hole) along the contour of the insulating block.

[0053] The thickness of the reflective layer 170 is less than the maximum thickness of the insulating structure 151 on the transparent conductive layer 140. This ensures that the sides of the reflective layer 170 are all inclined, thereby better preventing peeling of the reflective layer 170 and improving the coverage performance of the reflective layer 170.

[0054] In other embodiments, the thickness of the insulating block 152 can be less than half the maximum thickness of the insulating structure 151 above the transparent conductive layer 140. This configuration ensures that the insulating structure 151 ensures sufficient space between the reflective layer 170 and the insulating block 152 to form a good omnidirectional reflector structure. The thickness of the insulating block 152 is less than the thickness of the insulating structure 151 above the transparent conductive layer, and the ratio of the thickness of the insulating block 152 can be between 1 / 3 and 2 / 3.

[0055] In other embodiments, the insulating block may not be required.

[0056] It should be noted that, generally, the area of ​​the reflective layer 170 in direct contact with the transparent conductive layer 140 is smaller than the area of ​​the insulating block 152 in direct contact with the transparent conductive layer 140. The area of ​​the transparent conductive layer 140 in direct contact with the reflective layer 170 accounts for 3% to 50% of the chip area (the chip area is substantially equal to the area of ​​the transparent conductive layer 140 in this embodiment), preferably 5% to 20%, and more preferably 10%.

[0057] In this embodiment, adjacent semiconductor light-emitting stacks have a hole (not labeled), and the insulating structure 151 also covers the sidewalls and bottom of the hole. The fact that the insulating structure 151 covers both the sidewalls and bottom of the hole indicates that the insulating material layer used for the insulating structure 151 (see subsequent content) can be formed using a corresponding deposition process.

[0058] Figure 2 It further shows Figure 1 The semiconductor light emitting diode provided in this embodiment can be packaged in a flip-chip packaging structure to become a flip-chip semiconductor light emitting diode. Figure 2The figure shows a protective layer 180 (barrier) formed on the reflective layer 170. Protective layer 180 can be a metal protective layer, specifically a single or multi-layer metal thin film layer composed of one or more metals such as titanium, platinum, nickel (Ni), or gold (Au). Protective layer 180 can further enhance the reflective effect of reflective layer 170.

[0059] Please continue to refer to Figure 2 The semiconductor light emitting diode may further include a passivation layer 190 (passive layer), and further form a first electrode 210 and a second electrode 220. The first electrode 210 penetrates the passivation layer 190 and is located at Hole slot The insulating structure 151 at the bottom is electrically connected to the first conductive semiconductor layer 110. The second electrode 220 penetrates the passivation layer 190 to be electrically connected to the protection layer 180 (metal protection layer).

[0060] It should be noted that, although not shown in the figure, in other embodiments of the present invention, the semiconductor light emitting diode may also adopt a vertical packaging structure, thus becoming a vertically packaged semiconductor light emitting diode. When the vertical packaging structure is adopted, subsequent structures may include electrodes and a thermally conductive substrate.

[0061] Please refer to Figure 3 , showing Figure 2 The schematic diagram of the perspective view of the semiconductor light emitting diode shown is a top view. Figure 3 In the figure, only the insulating structure 151 and the insulating block 152 are marked to match Figure 1 and Figure 2 Shows the overall structure of a semiconductor light emitting diode. Figure 3 It can be seen that the aforementioned through hole, the through hole is Figure 3 It is displayed as small circles. Figure 3 The dotted line frame is shown in FIG. 1 , and the dotted line frame is used to distinguish the insulating structure 151 from the insulating block 152 ( Figure 3 Only two dotted boxes are shown as representatives), the insulating structure 151 is located within the dotted box, and the insulating block 152 is located outside the dotted box, but it is easy to see that they belong to the same insulating layer, but parts with different thicknesses are formed through corresponding steps. You can refer to the embodiment content of the subsequent method part of this specification.

[0062] In this embodiment, the substrate 100 may be sapphire (Al2O3). In other embodiments, the substrate 100 may be silicon (Si), silicon carbide (SiC), or gallium arsenide (GaAs). The first conductive semiconductor layer 110 may be an N-type doped gallium nitride (GaN) layer or a GaAs layer. The quantum well layer 120 may be a narrow-bandgap nitride film (not shown) containing indium (In) or a wide-bandgap nitride film (not shown). The second conductive semiconductor layer 130 may be a P-type doped GaN layer or a GaAs layer. The transparent conductive layer 140 may be indium tin oxide (ITO), zinc oxide (ZnO), or aluminum-doped zinc oxide (AZO).

[0063] In this embodiment, the material of the insulating structure 151 can be common insulating dielectric materials such as silicon, silicon nitride, silicon oxynitride or silicon oxide.

[0064] In this embodiment, the reflective layer 170 may be a single-layer or multi-layer metal thin film layer formed of one or more metals selected from platinum (Pt), titanium tungsten (TiW), or silver (Ag).

[0065] As previously mentioned, reflective layer 170 can be a corresponding metal film. Among various metals, silver has the highest reflectivity, reaching approximately 96%. Therefore, in this embodiment, a specific option is to use silver as reflective layer 170. By providing a silver mirror layer and multiple insulating blocks 152 to form an omnidirectional reflector structure, this embodiment can further improve reflectivity and enhance the overall brightness of the final product.

[0066] An embodiment of the present invention also provides a method for preparing a semiconductor light emitting diode.

[0067] The preparation method can be used to prepare Figure 1 The semiconductor light emitting diode shown in Figures 4 to 7 , and combined with reference Figure 1 .

[0068] The production method comprises:

[0069] like Figure 4 , forming the aforementioned semiconductor light-emitting stack on the substrate 100; the semiconductor light-emitting stack comprises a first conductive type semiconductor layer 110 located on the substrate 100, a quantum well layer 120 located on the first conductive type semiconductor layer 110, and a second conductive type semiconductor layer 130 located on the quantum well layer 120;

[0070] After forming the semiconductor light emitting stack, the corresponding Hole slot (not marked); although not shown in the figure, after the hole groove is formed, steps such as insulating the hole groove sidewalls can be performed;

[0071] Please continue to refer to Figure 4 , forming a transparent conductive layer 140 on the semiconductor light-emitting stack; the transparent conductive layer 140 can be formed by a deposition process, such as first depositing a corresponding transparent conductive material layer, and then performing a temperature treatment, so that the transparent conductive material layer forms an ohmic contact with the second conductive type semiconductor layer 130, and the transparent conductive material layer can be patterned by a yellow light mask process to form the transparent conductive layer 140;

[0072] like Figures 5 to 7 , forming an insulating structure 151, wherein the insulating structure 151 is at least partially formed on the transparent conductive layer 140, and the insulating structure 151 has an oblique side surface 151s, and the oblique side surface 151s of the insulating structure 151 surrounds the edge of the upper surface of the transparent conductive layer 140;

[0073] like Figure 7 , and combined with reference Figure 1 A reflective layer 170 is formed on the transparent conductive layer 140. The reflective layer 170 is located in the area surrounded by the oblique side surface 151s. The side surface of the reflective layer 170 covers the oblique side surface 151s of the insulating structure 151, so that the angle between the bottom surface and the side surface of the reflective layer 170 is an obtuse angle.

[0074] The reflective layer 170 may be a silver mirror layer, which may be formed by chemical vapor deposition (CVD). The reflective layer 170 formed in this case will terminate at the oblique side surface 151s.

[0075] exist Figures 5 to 7 In the process of forming the oblique side surface 151s, this embodiment specifically includes:

[0076] exist Figure 4 An insulating material layer (not shown) is formed on the structure shown to cover the semiconductor light-emitting stack and the transparent conductive layer 140. The insulating material layer can be formed using a corresponding deposition process. The insulating material layer will partially fill the holes and grooves in the semiconductor light-emitting stack (as described above, not labeled).

[0077] forming a patterned primary mask structure (not shown) on the insulating material layer;

[0078] Using the primary mask structure as a mask, the insulating material layer is etched to form an insulating layer (not marked) having an opening (not marked), such as Figure 5 ; Etching the insulating material layer includes steps such as using a yellow light mask to form a certain through-hole ( Figure 5In this embodiment, the through-hole area of ​​the insulating material layer can account for 3% to 50% of the area of ​​the insulating material layer (the area of ​​the insulating material layer is basically equal to the chip area), preferably 5% to 20%, and more preferably 10%.

[0079] like Figure 5 The insulating layer located on both the upper surface of the semiconductor light emitting stack and the upper surface of the transparent conductive layer 140 is used as the first insulating layer 150a (the first insulating layer 150a covers the bottom and sidewalls of the hole), as shown in FIG. Figure 6 , forming a secondary mask structure 160 on the first insulating layer 150 a to at least partially expose the upper surface of the first insulating layer 150 a , wherein the partially exposed upper surface of the first insulating layer 150 a is located above an edge of the upper surface of the transparent conductive layer 140 ; Figure 6 , a first portion P1 and a second portion P2 corresponding to one of the semiconductor light-emitting stacks are marked. The first portion P1 and the second portion P2 surround the first insulating layer 150a, the upper surface of which is partially covered by the secondary mask structure 160, to highlight that the secondary mask structure 160 also fills the hole groove; the secondary mask structure 160 can be made of a photoresist, that is, after forming a photoresist layer and performing processes such as exposure and development, patterning to form the secondary mask structure 160;

[0080] The first insulating layer 150a covers the bottom and sidewalls of the corresponding holes.

[0081] It should be noted that Figure 6 It is shown that the insulating layer located in the non-edge area of ​​the upper surface of the transparent conductive layer 140 is used as the second insulating layer 150b; the upper surface of the second insulating layer 150b without the secondary mask structure 160 is completely exposed;

[0082] The second mask structure 160 is used as a mask to etch the first insulating layer 150a. The remaining first insulating layer is etched into the insulating structure 151 having the oblique side surface 151s. Figure 7 In this embodiment, when the second mask structure 160 is used as a mask to etch the first insulating layer 150a, the etching method used may be a buffered oxide etchant (BOE) etching;

[0083] Figures 6 and 7 During the etching process, the first insulating layer 150a with the upper surface partially exposed is subjected to a certain amount of lateral etching, thereby forming an undercut structure of a certain distance, so that the side surface of this portion of the remaining insulating layer has a certain slope, that is, at this time, this portion of the first insulating layer 150a becomes the insulating structure 151;

[0084] At the same time, it can be seen from the above process that for the insulating structure 151 with inclined side surfaces that is finally formed, its inclined side surfaces 151s surround the hole groove in the top view direction (although the hole groove has been filled with the secondary mask structure 160 at this time, the position of the hole groove can still be identified in the top view direction).

[0085] From the above process, the second insulating layer 150b on the upper surface of which the secondary mask structure 160 is not formed is also etched at the same time. Therefore, it can be seen that when the insulating structure 151 is formed, the second insulating layer 150b not covering the secondary mask structure 160 is etched to form an insulating block 152. Figures 6 and 7 As shown. After the formation, there is a through hole between the insulating block 152 and the insulating structure 151, and there is also a through hole inside the insulating block 152. The insulating block 152 is the second insulating layer 150b that is not covered by the secondary mask structure 160, and is obtained by etching to a certain thickness. When the reflective layer 170 is subsequently formed, the reflective layer 170 also covers the insulating block 152. You can return to the reference Figure 1 .

[0086] It should be noted that, in this embodiment, the process of forming the reflective layer 170, in addition to the aforementioned deposition process, may also include evaporation after the completion of the above-mentioned buffered oxide etching solution etching. In this process, the metallic silver formed by the initial deposition can be mostly removed, and only the metallic silver in the desired area is retained to form the final reflective layer 170. This method of first retaining the deposited silver in the desired light-emitting area, and then evaporating to form a reflective silver mirror, and cooperating with the insulating block 152 and the transparent conductive layer 140 to form Omnidirectional reflection Semiconductor light-emitting diodes with a mirror structure can greatly improve the brightness of the final chip product.

[0087] It should be noted that after forming the insulating structure 151 and the insulating block 152 , the process of forming the reflective layer 170 may further include removing the secondary mask structure 160 .

[0088] As can be seen from the above, the process of forming the oblique side surface 151s in this embodiment utilizes the method of forming an undercut structure during the mask etching process. In other embodiments, other methods and principles can also be used to form an insulating structure with an oblique side surface.

[0089] Although not shown in the figure, Figure 1 After the structure shown, this embodiment can further continue to form structures such as a protective layer and other insulating layers, form structures such as an N electrode and a P electrode, and perform steps such as flip-chip packaging or vertical packaging.

[0090] The preparation method provided in this embodiment can be stably used in the process of manufacturing an omnidirectional reflective mirror structure, and can solve the abnormal curling of the end of the reflective layer 170, prevent the reflective layer 170 from peeling off and poor coverage, and is suitable for large-scale production.

[0091] The preparation method provided in this embodiment is simple in process, can achieve cost reduction, and has stable process and reliable and stable product quality. In addition, the final product structure fluctuation is small when different wafer sources (substrates) are made.

[0092] The semiconductor light emitting diode prepared in this embodiment was tested, and the results are shown in Table 1 below.

[0093] Product Code △LOP △VF S-45 +4.07% +0.017 S-55 +3.34% -0.013 S-60 +3.05% -0.016

[0094] Table 1

[0095] Table 1 shows that the light output power changes (ΔLOP) of the semiconductor light-emitting diodes prepared in this example are all positive values, proving that the reflectivity of the corresponding reflective layer is further improved by adopting the corresponding preparation method, thereby improving the optical performance; while the forward voltage change (ΔVF) remains basically unchanged, indicating stable electrical performance.

[0096] In addition to the results shown in Table 1 above, the test results also show the following three advantages:

[0097] 1) There is no abnormality in the peeling of the reflective layer, the yellow light process is stable, and the cost increase is small;

[0098] 2) The reflective layer has good cross-sectional coverage;

[0099] 3) The brightness of the product series has increased significantly (positively correlated with the light output power).

[0100] Another embodiment of the present invention provides another semiconductor light emitting diode, please refer to Figure 8 .

[0101] The semiconductor light emitting diode includes a semiconductor light emitting stack (not labeled) located on a substrate 100. The semiconductor light emitting stack includes a first conductive type semiconductor layer 110 located on the substrate 100, a quantum well layer 120 located on the first conductive type semiconductor layer 110, and a second conductive type semiconductor layer 130 located on the quantum well layer 120. A transparent conductive layer 140 is provided on the semiconductor light emitting stack, and a reflective layer 230 is provided on the transparent conductive layer 140. The semiconductor light emitting diode also includes an insulating structure 153, which is at least partially located on the transparent conductive layer 140. The insulating structure 153 has an oblique side surface 153s (labeled at Figure 11 and Figure 12 , please refer to Figure 11 and Figure 12), the oblique side surface 153s of the insulating structure 153 surrounds the edge of the upper surface of the transparent conductive layer 140, and the side surface of the reflective layer 230 covers the oblique side surface 153s of the insulating structure 153, so that the angle between the bottom surface and the side surface of the reflective layer 230 is an obtuse angle.

[0102] The above structure is the same as that of the aforementioned embodiment, and reference may be made to the corresponding contents of the aforementioned embodiment.

[0103] In this embodiment, a protective layer 240 is provided on the reflective layer 230. Therefore, the reflective layer 230 may be thinner than the reflective layer 170 in the previous embodiment.

[0104] In this embodiment, at least a portion of the side surface of the protective layer 240 covers the oblique side surface 153s of the insulating structure 153, so that the angle between the bottom surface and the side surface of the protective layer 240 is an obtuse angle. Specifically, in this embodiment, the protective layer 240 also covers a portion of the upper surface of the insulating structure 153. In this case, the side surface of the protective layer 240 has two parts. Only the side surface of the protective layer 240 that is directly connected to the bottom surface forms an obtuse angle with the bottom surface of the protective layer 240. The other side surface is located above the upper surface of the insulating structure 153 and is not directly connected to the bottom surface. Therefore, this side surface does not form an angle with the bottom surface.

[0105] In this embodiment, the protective layer 240 may be a metal protective layer, specifically a single-layer or multi-layer metal thin film layer composed of one or more metals selected from titanium, platinum, nickel (Ni) or gold (Au).

[0106] In this embodiment, the thickness of the reflective layer 230 is less than or equal to the maximum thickness of the insulating structure 153 on the transparent conductive layer 140. As previously described, the maximum thickness of the insulating structure 153 on the transparent conductive layer 140 is the height of the oblique side surface 153s. The thickness of the reflective layer 230 being less than or equal to the maximum thickness of the insulating structure 153 on the transparent conductive layer 140 ensures that all side surfaces of the reflective layer 230 are oblique, thereby better preventing the reflective layer 230 from curling up at the ends, i.e., preventing the side surfaces from peeling, and improving the coverage of the reflective layer 230.

[0107] At the same time, in this embodiment, the protective layer 240 is further formed on the reflective layer 230, and at least part of the side surface of the protective layer 240 also becomes an inclined side surface, covering the inclined side surface 153s of the insulating structure 153. At this time, the protective layer 240 further suppresses the peeling of the reflective layer 230, and the protective layer 240 itself and the insulating structure 153 can also achieve better coverage performance.

[0108] Figure 9 It further shows Figure 8More structures of the semiconductor light-emitting diode shown. The semiconductor light-emitting diode provided in this embodiment adopts a flip-chip packaging structure, resulting in a flip-chip semiconductor light-emitting diode. A passivation layer 250 may be further provided on the protective layer 240, and a first electrode 260 and a second electrode 270 may be further formed. The first electrode 260 penetrates the passivation layer 250 and the insulating structure 153 at the bottom of the hole to electrically connect to the first conductive type semiconductor layer 110. The second electrode 270 penetrates the passivation layer 250 to electrically connect to the protective layer 240 (metal protective layer).

[0109] It should be noted that, although not shown in the figures, in other embodiments of the present invention, the semiconductor light-emitting diode may also adopt a vertical packaging structure, resulting in a vertically packaged semiconductor light-emitting diode. In the case of a flip-chip structure, subsequent structures include a passivation layer and electrodes. In the case of a vertical packaging structure, subsequent structures may include electrodes and a thermally conductive substrate.

[0110] Please refer to Figure 10 , showing Figure 9 The schematic diagram of the perspective view of the semiconductor light emitting diode shown is a top view. Figure 10 In the figure, only the insulating structure 153 is marked to match Figure 8 and Figure 9 Shows the overall structure of a semiconductor light emitting diode. Figure 10 It can be seen that the dotted box in the figure is used to distinguish the area where the insulation structure 153 is located, and reference can be made to the embodiment content in the subsequent method part of this specification.

[0111] Another embodiment of the present invention provides another method for manufacturing a semiconductor light emitting diode.

[0112] The preparation method can be used to prepare Figure 8 The semiconductor light emitting diode shown in Figures 11 to 12 , and combined with reference Figure 8 , you can also refer to Figures 4 to 6 Corresponding content.

[0113] Specifically, the preparation method includes:

[0114] like Figure 11 , and combined with reference Figures 4 to 6 , forming the aforementioned semiconductor light-emitting stack on a substrate 100; the semiconductor light-emitting stack comprises a first conductive type semiconductor layer 110 located on the substrate 100, a quantum well layer 120 located on the first conductive type semiconductor layer 110, and a second conductive type semiconductor layer 130 located on the quantum well layer 120; forming a transparent conductive layer 140 on the semiconductor light-emitting stack;

[0115] like Figure 11 , and combined with reference Figures 4 to 6, forming an insulating structure 153 , wherein the insulating structure 153 is at least partially formed on the transparent conductive layer 140 , and the insulating structure 153 has an oblique side surface 153 s , and the oblique side surface 153 s of the insulating structure 153 surrounds the edge of the upper surface of the transparent conductive layer 140 .

[0116] Specifically, from Figures 4 to 6 , and then from Figure 6 Directly to Figure 11 The process includes:

[0117] An insulating material layer (not shown) is formed to cover Figure 4 The semiconductor light emitting stack and the transparent conductive layer 140 are shown; a patterned primary mask structure (not shown) is formed on the insulating material layer; the insulating material layer is etched using the primary mask structure as a mask to form an insulating layer, the insulating layer including a first insulating layer 150a and a second insulating layer 150b, as shown Figure 5 ;

[0118] like Figure 6 A secondary mask structure 160 is formed on the first insulating layer 150a located on both the upper surface of the semiconductor light-emitting stack and the upper surface of the transparent conductive layer 140, at least partially exposing the upper surface of the first insulating layer 150a. The partially exposed upper surface of the first insulating layer 150a is located above the edge of the upper surface of the transparent conductive layer 140. In addition, the upper surface of the second insulating layer 150b, on which the secondary mask structure 160 is not formed, is completely exposed.

[0119] Continue to refer Figure 6 , using the secondary mask structure 160 as a mask, etching all the insulating layers (all the insulating layers include the first insulating layer 150a with the secondary mask structure 160 formed on the upper surface and the second insulating layer 150b without the secondary mask structure 160 formed on the upper surface) to form a remaining insulating layer (not distinguished by labeling), wherein the remaining insulating layer covered by the secondary mask structure 160 is etched into an insulating structure 153 having an oblique side surface 153s, as shown in FIG. Figure 11 shown.

[0120] In this embodiment, the first insulating layer 150a whose upper surface is partially exposed is also subjected to a certain degree of lateral etching to form a bottom cut structure of a certain distance, so that the side surface of this remaining insulating layer has a certain slope. This remaining insulating layer becomes the insulating structure 153, and the second insulating layer 150b whose upper surface does not have a secondary mask structure 160 is completely etched away.

[0121] Figures 11 to 12, showing that in this embodiment, the secondary mask structure 160 is subsequently removed, and then a reflective layer 230 is formed on the transparent conductive layer 140. The reflective layer 230 is located in the area surrounded by the oblique side surface 153s. The side surface of the reflective layer 230 covers the oblique side surface 153s of the insulating structure 153, so that the angle between the bottom surface and the side surface of the reflective layer 230 is an obtuse angle.

[0122] Please refer back to Figure 8 , showing that the preparation method of this embodiment also includes: after forming the reflective layer 230, forming a protective layer 240 to cover the reflective layer 230, and at least part of the side surface of the protective layer 240 covers the inclined side surface 153s of the insulating structure 153, so that the angle between the bottom surface and the side surface of the protective layer 240 is an obtuse angle.

[0123] The preparation method provided in this embodiment can use a silver mirror as the reflective layer 230 to solve the problem of poor coverage or easy peeling of the end of the reflective layer.

[0124] The preparation method provided in this embodiment can be further followed by a vertical packaging step, and a substrate with high thermal conductivity can be used as the packaging substrate, such as a silicon substrate and a germanium substrate.

[0125] The preparation method provided in this embodiment can be further followed by a flip-chip packaging step to avoid wire bonding and improve light efficiency and heat dissipation.

[0126] Another embodiment of the present invention provides another semiconductor light emitting diode, please refer to Figures 13 to 15 .

[0127] like Figure 13 The semiconductor light-emitting diode includes a semiconductor light-emitting stack (not labeled) on a substrate 300 and a transparent conductive layer 340 on the semiconductor light-emitting stack. The semiconductor light-emitting stack includes a first-conductivity-type semiconductor layer 310, a quantum well layer 320 on the first-conductivity-type semiconductor layer 310, and a second-conductivity-type semiconductor layer 330 on the quantum well layer 320.

[0128] An insulating layer (including different parts located in different regions) is disposed on the transparent conductive layer 340. The insulating layer includes a first region A and a second region B surrounding the first region A. Figure 13 In FIG. 3 , the insulating layer in the first region A is labeled as insulating layer 351 , and the insulating layer in the second region B is labeled as insulating layer 352 .

[0129] Please continue to refer to Figure 13The first region A has a first surface a (i.e., the insulating layer 351 has a first surface a), and the second region B has a second surface b (i.e., the insulating layer 352 has a second surface b), wherein the first surface a is lower than the second surface b, and there is a connecting side surface c between the first surface a and the second surface b, and a reflective layer 360 is arranged on the first region of the insulating layer, and the edge of the reflective layer 360 is located on the connecting side surface c.

[0130] like Figure 13 In this embodiment, the thickness of the insulating layer in the first region A (ie, the thickness of the insulating layer 351 ) is one third to two thirds of the thickness in the second region B (ie, the thickness of the insulating layer 352 ).

[0131] like Figure 13 In this embodiment, the thickness of the reflective layer 360 is less than or equal to the thickness of the insulating layer in the second region B (ie, the thickness of the insulating layer 352 ).

[0132] Please refer to Figure 14 , further showing that in this embodiment, Figure 13 The schematic diagram of the partial structure of the semiconductor light-emitting diode after the electrode is fabricated is shown, wherein a protective layer 370 is provided on the reflective layer 360, and at least a portion of the side surface of the protective layer 370 covers the connecting side surface c, so that the angle between the bottom surface of the protective layer 370 and the side surface (in this case, a portion of the side surface) is an obtuse angle.

[0133] Please refer to further Figure 14 The protective layer 370 may further have a passivation layer 380 thereon, and the passivation layer 380 may have a thermal conductive layer 390 thereon.

[0134] Please refer to further Figure 14 , Figure 14 Compared to Figure 13 The substrate 300 is removed, and the first electrode 410 is formed to connect to the first conductive semiconductor layer 310. The second electrode 420 is provided on the thermal conductive layer 390. This forms a vertical package structure. In other embodiments, the semiconductor light emitting diode provided in this embodiment can also have a flip-package structure.

[0135] Please refer to Figure 15 , showing Figure 14 The schematic diagram of the perspective view of the semiconductor light emitting diode shown is a top view. Figure 15 In the figure, only insulation layer 352 and insulation layer 351 are marked to match Figure 13 and Figure 14 Shows the overall structure of a semiconductor light emitting diode. Figure 15 It can be seen that the insulating layer 351 has corresponding through holes (refer to the through holes in the previous embodiment). Figure 15 It is displayed as small circles. Figure 15 Multiple dotted boxes are shown in the figure. The multiple dotted boxes are used to distinguish the insulating layer 352 from the insulating layer 351. The insulating layer 352 is inside the dotted box (belonging to the second area B), and the insulating layer 351 is outside the dotted box (belonging to the first area A). Please refer to Figure 13 As mentioned above, they belong to the same insulating layer, but are formed into parts with different thicknesses through corresponding steps. Please refer to the embodiment content in the subsequent method part of this specification.

[0136] For more information on the structure, properties and advantages of the semiconductor light emitting diode provided in this embodiment, please refer to the corresponding contents of the aforementioned embodiments.

[0137] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A semiconductor light emitting diode comprising a semiconductor light emitting stack and an insulating layer located above the semiconductor light emitting stack, characterized in that: The insulating layer includes a first region and a second region connected to the first region, the first region has a first surface, the second region has a second surface, wherein the first surface is lower than the second surface, and a connecting side surface is provided between the first surface and the second surface, a reflective layer is provided on the first region of the insulating layer, and an edge of the reflective layer is located on the connecting side surface; the connecting side surface is an oblique side surface; and the edges of the reflective layer are all surrounded by the insulating layer having the oblique side surface.

2. The semiconductor light emitting diode according to claim 1, wherein: The invention also includes a transparent conductive layer, which is located between the semiconductor light-emitting stack and the insulating layer.

3. The semiconductor light emitting diode according to claim 2, wherein: The insulating layer has a bottom surface, which covers a portion of the upper surface of the semiconductor light-emitting stack and a portion of the upper surface of the transparent conductive layer.

4. The semiconductor light emitting diode according to claim 2, wherein: The portion of the insulating layer located in the first region has a plurality of through holes, and the reflective layer contacts the transparent conductive layer through the plurality of through holes.

5. The semiconductor light emitting diode according to claim 4, wherein: The contact area between the reflective layer and the transparent conductive layer is smaller than the area of ​​the insulating layer located in the first region.

6. The semiconductor light emitting diode according to claim 1, wherein: The invention also includes a protective layer, which covers the reflective layer and the oblique side surface and at least partially covers the second surface of the second area of ​​the insulating layer.

7. The semiconductor light emitting diode according to claim 1, wherein: The thickness of the reflective layer is less than or equal to the thickness of the insulating layer in the first region.

8. The semiconductor light emitting diode according to claim 1, wherein: The thickness of the insulating layer in the first region is 200-1200 nm.

9. The semiconductor light emitting diode according to claim 1, wherein: The thickness of the insulating layer in the first region is one third to two thirds of the thickness of the insulating layer in the second region.

10. The semiconductor light emitting diode according to claim 1, wherein: It also includes a passivation layer, a first electrode and a second electrode. The semiconductor light-emitting stack includes a first conductive semiconductor layer, a second conductive semiconductor layer and a quantum well layer located therebetween. The passivation layer is formed on the reflective layer. The first electrode and the second electrode are located on the passivation layer. The first electrode penetrates the passivation layer and the insulating layer to be electrically connected to the first conductive semiconductor layer. The second electrode penetrates the passivation layer to be electrically connected to the second conductive semiconductor layer.

11. A semiconductor light emitting diode, characterized in that: include: A semiconductor light emitting stack having a first surface and a peripheral surface connected to the first surface; an insulating structure, at least partially located on a peripheral surface of the semiconductor light-emitting stack, having an obtuse angle between the oblique side surface and the bottom surface of the space region, wherein the oblique side surface forms a space region above the first surface of the semiconductor light-emitting stack; a reflective layer, located on the first surface of the semiconductor light-emitting stack, wherein an edge of the reflective layer is located on the oblique side surface; The transparent conductive layer is located on the semiconductor light emitting stack; the oblique side surfaces of the insulating structure surround the upper surface edge of the transparent conductive layer.

12. The semiconductor light emitting diode according to claim 11, characterized in that: The invention also includes a protection layer, which is formed on the reflection layer and covers the oblique side surfaces of the insulation structure.

13. The semiconductor light emitting diode according to claim 11, wherein: It also includes a passivation layer, a first electrode and a second electrode. The semiconductor light-emitting stack includes a first conductive semiconductor layer, a second conductive semiconductor layer and a quantum well layer located therebetween. The passivation layer is formed on the reflective layer. The first electrode and the second electrode are located on the passivation layer. The first electrode penetrates the passivation layer and the insulating structure to be electrically connected to the first conductive semiconductor layer. The second electrode penetrates the passivation layer to be electrically connected to the second conductive semiconductor layer.

14. The semiconductor light emitting diode according to claim 11, wherein: The bottom surface of the insulating structure covers a portion of the upper surface of the semiconductor light-emitting stack and a portion of the upper surface of the transparent conductive layer.

15. The semiconductor light emitting diode according to claim 11, wherein: It also includes an insulating block connected to the insulating structure, the insulating block has a plurality of through holes, the reflective layer covers the insulating block, and the reflective layer and the insulating block form an omnidirectional reflector structure.

16. The semiconductor light emitting diode according to claim 15, characterized in that: The thickness of the insulating block is smaller than the maximum thickness of the insulating structure.

17. The semiconductor light emitting diode according to claim 15, wherein: The thickness of the insulating block is less than two-thirds of the maximum thickness of the insulating structure.

18. The semiconductor light emitting diode according to claim 15, wherein: The thickness of the reflective layer is less than or equal to the maximum thickness of the insulating structure.

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