LED chip and light emitting device

Abstract

The utility model discloses a kind of LED chip and light-emitting device, the LED chip includes light-emitting structure and light-adjusting structure on light-emitting structure, the light-emitting structure includes at least one light-emitting unit, the light-adjusting structure includes silicon isolation layer and light-adjusting unit, the isolation groove that penetrates silicon isolation layer is equipped in the above of each light-emitting unit, at least part isolation groove is filled with light-adjusting unit, the silicon isolation layer includes first sidewall and second sidewall, the first sidewall is adjacent to the light-emitting structure, the second sidewall is compared with first sidewall away from the light-emitting structure, the first sidewall is formed with particle convex micro-nano structure. The first sidewall of silicon isolation layer in the utility model LED chip can improve the capture ability to light, obtain contrast high, more excellent stability light-emitting device.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor device technology, specifically relating to an LED chip and a light-emitting device. Background Technology

[0002] Light-emitting diodes (LEDs) are one of the mainstream display technologies currently, with broad application prospects in many fields. In existing technologies, silicon wafers are typically used as substrates to fabricate multiple light-emitting units on the substrate. Then, dimming structures are fabricated on the light-emitting surfaces of the light-emitting units. Finally, the entire wafer is cut to obtain multiple LED chips.

[0003] Existing whole-wafer dicing methods include blade dicing, laser full dicing, and hidden dicing. Blade dicing uses a blade rotating at high speed around a spindle to cut through the gap between adjacent LED chips (dicing track), thus dividing the entire wafer. Blade dicing is simple to operate and inexpensive, suitable for large LED chips and thick wafers. However, it has low precision, slow cutting speed, and is prone to blade chipping during the process. It also easily generates stress concentration, microcracks, and edge chipping in the LED chip, negatively impacting the reliability and performance of the LED chip, severely affecting product yield and production efficiency. Laser full dicing uses a high-power laser to irradiate the wafer surface, rapidly melting or igniting the material in the dicing track area. Simultaneously, a high-speed airflow blows away the molten or burning material, cutting through the dicing track and dividing the wafer. Laser dicing offers high precision, high speed, and a small heat-affected zone, suitable for small LED chips and thin wafers. However, the thermal and mechanical stresses generated during laser cutting can damage or degrade the performance of LED chips, and the high temperatures generated during laser cutting can easily cause deformation of the dimming and filtering units in the LED chip. The hidden dicing method involves first using laser energy to cut the interior of the wafer, then applying external pressure to the adhesive tape attached to the back of the wafer to break it, thus obtaining the separated LED chips. The hidden dicing method does not produce wafer material debris and allows for narrower dicing channels, resulting in more LED chips. However, it is prone to causing LED chip warping and uneven dicing lines.

[0004] In summary, existing dicing methods all have significant advantages and disadvantages. Furthermore, the fabrication processes and structures vary depending on the specific LED chip being diced. Therefore, it is necessary to select an appropriate dicing process based on the specific problems encountered to ensure that the resulting individual chips exhibit excellent performance. In addition, with the rapid development of microdisplay devices, LED chip structures in the microdisplay field are far more complex than conventional LED chip structures. Besides the conventional chip electrode structure, they also include dimming and filtering structures, requiring consideration of more factors during fabrication to ensure their performance meets the requirements of the microdisplay field.

[0005] Therefore, in order to address the aforementioned technical problems, it is necessary to provide an LED chip and a light-emitting device. Utility Model Content

[0006] The purpose of this invention is to provide an LED chip and a light-emitting device that can improve the contrast of the LED chip and facilitate the filling of black glue during the manufacturing process of the light-emitting device.

[0007] To achieve the above objectives, the technical solution provided by an embodiment of this utility model is as follows:

[0008] An LED chip includes a light-emitting structure and a dimming structure located on the light-emitting structure. The light-emitting structure includes at least one light-emitting unit. The dimming structure includes a silicon isolation layer and a dimming unit. The silicon isolation layer has an isolation groove penetrating the silicon isolation layer above each light-emitting unit. At least a portion of the isolation groove is filled with a dimming unit. The silicon isolation layer includes a first sidewall and a second sidewall. The first sidewall is adjacent to the light-emitting structure, and the second sidewall is farther away from the light-emitting structure than the first sidewall. A granular protrusion-like micro / nano structure is formed on the first sidewall.

[0009] In one embodiment, the second sidewall has a layered structure.

[0010] In one embodiment, the contact angle between the surface of the first sidewall and the liquid is 0° to 5°.

[0011] In one embodiment, the height of the first sidewall is 10 μm to 50 μm.

[0012] In one embodiment, the height of the second sidewall is 25 μm to 65 μm.

[0013] In one embodiment, the second sidewall is perpendicular to the side surface of the silicon isolation layer away from the light-emitting structure.

[0014] In one embodiment, the angle between the first sidewall and the side surface of the silicon isolation layer with the light-emitting structure is an obtuse angle.

[0015] In one embodiment, at least one of the dimming units is provided with a filter unit.

[0016] In one embodiment, the light-emitting structure includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit spaced apart. The silicon isolation layer has a first isolation trench, a second isolation trench, and a third isolation trench above the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit, respectively. The first isolation trench, the second isolation trench, and the third isolation trench are filled with a first dimming unit, a second dimming unit, and a third dimming unit. The first dimming unit, the second dimming unit, and the third dimming unit are respectively provided with a first filter unit, a second filter unit, and a third filter unit.

[0017] Another embodiment of this utility model provides the following technical solution:

[0018] A light-emitting device includes a substrate, a plurality of LED chips encapsulated on the substrate, and black adhesive, wherein the black adhesive is filled between adjacent LED chips, and the LED chips are the aforementioned LED chips.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention utilizes a combination of laser cutting and blade cutting processes to achieve whole-wafer cutting, thus fully leveraging the advantages of both processes and effectively avoiding any adverse effects on LED chips.

[0021] This invention utilizes laser cutting technology to form laser-induced micro / nano structures on the sidewalls of a silicon isolation layer. This facilitates the filling of black glue during the subsequent fabrication of light-emitting devices, improves the stability of the light-emitting devices, and reduces the reflectivity of light in the visible to near-infrared band from 35% to 1%~2%, achieving a "super black silicon" effect. This enhances the light-capturing ability, thereby improving the pixel contrast of the light-emitting devices and obtaining light-emitting devices with superior luminous efficacy. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the LED chip structure in Embodiment 1 of this utility model;

[0024] Figure 2 This is an optical microscope characterization image of the first and second sidewalls of the LED chip in Embodiment 1 of this utility model;

[0025] Figures 3a-3f This is a process flow diagram of the LED chip fabrication method in Embodiment 1 of this utility model;

[0026] Figure 4 This is a three-dimensional structural schematic diagram of the light-emitting device in Embodiment 1 of this utility model;

[0027] Figure 5 This is a top view of the LED chip in Embodiment 2 of this utility model;

[0028] Figure 6 is an optical microscope characterization view of the LED chip obtained after laser cutting from the second surface and blade cutting from the first surface in Example 2 of the present utility model;

[0029] Figure 7 is an optical microscope characterization view of the LED chip in Example 2 of the present utility model.

[0030] Brief Description of Main Reference Numerals in the Drawings:

[0031] 1-LED chip, 101-first light-emitting unit, 102-second light-emitting unit, 103-third light-emitting unit, 21-silicon isolation layer, 211-first isolation trench, 212-second isolation trench, 213-third isolation trench, 221-first dimming unit, 222-second dimming unit, 223-third dimming unit, 301-first light filtering unit, 302-second light filtering unit, 303-third light filtering unit, 40-silicon wafer, 501-first white film, 502-second white film, 60-substrate, 70-black glue. Detailed Description of the Preferred Embodiments

[0032] In order to make those skilled in the art better understand the technical solutions in the present disclosure, the following will clearly and completely describe the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

[0033] The present utility model discloses an LED chip, comprising a light-emitting structure and a dimming structure located on the light-emitting structure. The light-emitting structure includes at least one light-emitting unit. The dimming structure includes a silicon isolation layer and a dimming unit. The silicon isolation layer is provided with an isolation trench penetrating through the silicon isolation layer above each light-emitting unit, and at least part of the isolation trenches is filled with the dimming unit. The silicon isolation layer includes a first side wall and a second side wall. The first side wall is adjacent to the light-emitting structure, the second side wall is farther away from the light-emitting structure than the first side wall, and a micro-nano structure in the shape of particle protrusions is formed on the first side wall.

[0034] The present utility model further discloses a light-emitting device, comprising a substrate, a plurality of LED chips packaged on the substrate, and black glue filled between adjacent LED chips. The LED chips are the above-mentioned LED chips or LED chips prepared according to the above-mentioned preparation method.

[0035] The present utility model will be further described below with reference to specific examples.

[0036] Example 1:

[0037] Ref Figure 1 and combined Figure 2 As shown, the LED chip 1 in this embodiment includes a light-emitting structure and a dimming structure located on the light-emitting structure. The light-emitting structure includes at least one light-emitting unit. The dimming structure includes a silicon isolation layer 21 and a dimming unit. The silicon isolation layer 21 has an isolation groove that penetrates the silicon isolation layer above each light-emitting unit. At least a portion of the isolation groove is filled with a dimming unit. The silicon isolation layer includes a first sidewall S1 and a second sidewall S2. The first sidewall S1 is adjacent to the light-emitting structure, and the second sidewall S2 is farther away from the light-emitting structure than the first sidewall S1. A particle-like protrusion micro-nano structure is formed on the first sidewall S1.

[0038] Specifically, the light-emitting structure in this embodiment includes a first light-emitting unit 101, a second light-emitting unit 102, and a third light-emitting unit 103 spaced apart. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 are all blue light-emitting units that emit blue light toward the dimming structure. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 each include at least a P-type semiconductor layer, an active layer, an N-type semiconductor layer, a P electrode electrically connected to the P-type semiconductor layer, and an N electrode electrically connected to the N-type semiconductor layer.

[0039] Furthermore, combined Figure 3c As shown, the silicon isolation layer 21 has a first isolation trench 211, a second isolation trench 212, and a third isolation trench 213 above the first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103, respectively. The first isolation trench 211, the second isolation trench 212, and the third isolation trench 213 are respectively filled with a first dimming unit 221, a second dimming unit 222, and a third dimming unit 223.

[0040] Specifically, the first dimming unit 221 is used to convert blue light into red light, the second dimming unit 222 is used to convert blue light into green light, and the third dimming unit 223 is a transparent unit that does not perform wavelength conversion on the incident light.

[0041] Preferably, the third dimming unit 223 is a transparent light diffusion unit, including a transparent substrate layer and scattering particles that can scatter blue light dispersed therein, so that the incident light is scattered without changing the wavelength, thereby enhancing the uniformity of light output. The material of the transparent substrate layer is epoxy resin.

[0042] More specifically, the first dimming unit 221 and the second dimming unit 222 each include a transparent substrate layer and any one or more of quantum dot material, inorganic phosphor material or organic phosphor material dispersed in the second transparent substrate layer, wherein the material of the transparent substrate layer is epoxy resin adhesive.

[0043] Furthermore, at least one dimming unit is provided with a filter unit. In this embodiment, the first dimming unit 221, the second dimming unit 222 and the third dimming unit 223 are respectively provided with a first filter unit 301, a second filter unit 302 and a third filter unit 303.

[0044] Specifically, the first filter unit 301 is used to filter blue light in red light, the second filter unit 302 is used to filter blue light in green light, and the third filter unit 303 is used to filter stray light in blue light, making the chromaticity of blue light more standard. The first filter unit 301, the second filter unit 302, and the third filter unit 303 all include a substrate layer and quantum dot material dispersed in the substrate layer, and the material of the substrate layer is an organic material.

[0045] Furthermore, the second sidewall has a layered structure.

[0046] Specifically, the surface of the first sidewall S1 is a laser-cut surface, and the surface of the second sidewall S2 is a blade-cut surface. The particle-protruding micro-nano structure formed on the first sidewall S1 has strong anti-reflection properties, which can reduce the reflectivity of light in the visible to near-infrared band from 35% to 1%~2%, achieve the "super black silicon" effect, improve the light-capturing ability, and thus improve the contrast of the light-emitting device subsequently fabricated.

[0047] In addition, the contact angle between the surface of the first sidewall S1 and the liquid is 0°~5°. When several LED chips are subsequently packaged onto the substrate to form a light-emitting device, it is beneficial for the black glue to fill between two adjacent LED chips, which can effectively avoid the generation of cavities and bubbles.

[0048] Furthermore, the height of the first sidewall S1 is 10μm~50μm, and the height of the second sidewall S2 is 25μm~65μm.

[0049] Preferably, in this embodiment, the height of the silicon isolation layer is 65 μm, the height of the first sidewall S1 is 25 μm, and the height of the second sidewall S2 is 40 μm.

[0050] The method for preparing the LED chip in this embodiment includes the following steps:

[0051] S1, Reference Figure 3a As shown, a silicon wafer 40 is provided, which includes a first surface and a second surface disposed opposite to each other.

[0052] S2, Reference Figure 3b As shown, several light-emitting structures are prepared on the first surface, and each light-emitting structure includes at least one light-emitting unit.

[0053] Specifically, the light-emitting structure in this embodiment includes a first light-emitting unit 101, a second light-emitting unit 102, and a third light-emitting unit 103 spaced apart. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 are all blue light-emitting units, and all emit blue light toward the direction adjacent to the silicon wafer 40. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 each include at least a P-type semiconductor layer, an active layer, an N-type semiconductor layer, a P electrode electrically connected to the P-type semiconductor layer, and an N electrode electrically connected to the N-type semiconductor layer.

[0054] S3, Reference Figure 3c As shown, the silicon wafer 40 is etched from the second surface to form an isolation trench that penetrates the silicon wafer 40 above each light-emitting unit.

[0055] Specifically, before etching the silicon wafer 40, it is necessary to thin the silicon wafer 40 to obtain a silicon isolation layer 21 with a thickness that meets the requirements, and then etch the thinned silicon wafer 40.

[0056] More specifically, in this embodiment, the silicon isolation layer 21 is etched to form a first isolation trench 211, a second isolation trench 212, and a third isolation trench 213 above the first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103, respectively.

[0057] S4, Reference Figure 3d As shown, a dimming unit is fabricated in at least a portion of the isolation trough.

[0058] Specifically, in this embodiment, the first dimming unit 221, the second dimming unit 222, and the third dimming unit 223 are respectively filled in the first isolation groove 211, the second isolation groove 212, and the third isolation groove 213.

[0059] More specifically, the first dimming unit 221 is used to convert blue light into red light, the second dimming unit 222 is used to convert blue light into green light, and the third dimming unit 223 is a transparent unit that does not perform wavelength conversion on the incident light.

[0060] In addition, after the dimming unit is prepared, this embodiment also includes preparing a first filter unit 301, a second filter unit 302 and a third filter unit 303 above the first dimming unit 221, the second dimming unit 222 and the third dimming unit 223 respectively.

[0061] S5, Participant Figure 3e As shown, a first cutting process is used to cut a portion of the silicon wafer adjacent to the light-emitting structure from the first surface along the interval region between adjacent light-emitting structures. The first cutting process is a laser cutting process.

[0062] Specifically, before cutting, the second surface of the whole wafer, which is prepared with the first filter unit 301, the second filter unit 302 and the third filter unit 303, needs to be attached to the first white film 501.

[0063] In this embodiment, the thickness of the thinned silicon wafer is 65μm. A cutting groove with a depth of 25μm is formed on the first surface using a laser cutting process. Due to the influence of the laser cutting process, the cutting groove is V-shaped, that is, the angle between the first sidewall and the side surface of the silicon isolation layer with the light-emitting structure is an obtuse angle, and a particle-shaped micro-nano structure is formed on the first sidewall whose surface is the laser-cut surface.

[0064] More specifically, the laser power is 0.5W~1W and the laser frequency is 120Hz~150Hz. By using a high-frequency, low-power laser and controlling the cutting depth to a shallow depth of 20μm~30μm, the line width of the cutting area is improved, which can keep the hot, accumulated slag away from the light-emitting structure.

[0065] Furthermore, after cutting silicon wafers using laser cutting technology, the content of Si-OH bonds on the laser-cut surface is significantly increased by more than 20% compared to silicon that has not undergone laser ablation. This reduces the contact angle between the laser-cut surface and the liquid to 0°~5°, resulting in the formation of a superhydrophilic layer on the first sidewall. This is beneficial for the filling of black glue when LED chips are subsequently packaged onto the substrate to form light-emitting devices.

[0066] In addition, since the transparent substrate layer of the dimming unit is epoxy resin and the substrate layer of the filter unit is organic material, the silicon wafer can only be cut from the first surface using laser cutting technology. At the same time, the depth of laser cutting should not be too deep to avoid damaging the dimming unit and the filter unit on the second surface.

[0067] S6, Participant Figure 3f As shown, a second cutting process is used to cut a portion of the silicon wafer away from the light-emitting structure from the second surface along the interval region between adjacent light-emitting structures.

[0068] Specifically, the whole wafer structure with laser cutting grooves is first removed from the first white film 501 and flipped over. The first surface with the light-emitting structure is then attached to the second white film 502, and the whole wafer is then cut using the second cutting process.

[0069] More specifically, the second cutting process is a blade cutting process. In the second cutting process, the rotational speed of the blade is 30000 rpm to 40000 rpm, the height of the blade is 90 μm to 100 μm, and an overcut of about 10 μm is required during blade cutting, that is, the blade needs to extend into the cutting groove formed by laser cutting to ensure that the silicon wafer is cut through and the separation of LED chips is realized. The blade cutting process is used to cut the silicon wafer from the second surface to form a second side wall whose surface is a blade-cut surface. During cutting, the blade and the silicon wafer form an R-shape, so that irregular micro-cracks generated during blade cutting diffuse from the second surface and will not affect the performance of the light-emitting structure on the first surface. After the cutting is completed, a layered stripe structure is formed on the second side wall.

[0070] See Figure 4 as shown, the light-emitting device in this embodiment includes a substrate 60, a plurality of LED chips 1 packaged on the substrate, and black glue 70, and the black glue 70 is filled between adjacent LED chips 1. Since the surface of the first side wall is a laser-cut surface on which a super-hydrophilic layer is formed, after a plurality of LED chips are packaged on the substrate, the black glue can more easily enter the gaps between adjacent LED chips during black glue filling, which can effectively avoid the generation of cavities and bubbles and improve the overall stability.

[0071] Embodiment 2:

[0072] The LED chip, its preparation method, and the light-emitting device in this embodiment are substantially the same as those in Embodiment 1, except that in this embodiment, the first light filtering unit 301, the second light filtering unit 302, and the third light filtering unit 303 are arranged non-parallel, for example Figure 5 as shown in the figure.

[0073] See Figure 6 as shown, if the silicon wafer is cut from the second surface by using the laser cutting process, the base material layer of the light filtering unit will be melted, causing the light filtering unit to deform, and the silicon on the second surface will turn white, which reduces the contrast of the LED chip.

[0074] See Figure 7 as shown, compared with Figure 6 the case where the silicon wafer is cut from the second surface by the laser cutting process, cutting the silicon wafer from the first surface by the laser cutting process and cutting the silicon wafer from the second surface by the blade cutting process can obtain LED chips with excellent quality.

[0075] It can be seen from the above technical solutions that the present utility model has the following beneficial effects:

[0076] In the present utility model, the laser cutting process combined with the blade cutting process is used to realize the cutting of the whole wafer, so that the advantages of both the laser cutting process and the blade cutting process are fully utilized, and the adverse effects of the laser cutting process and the blade cutting process on the LED chip can be effectively avoided;

[0077] This invention utilizes laser cutting technology to form laser-induced micro / nano structures on the sidewalls of a silicon isolation layer. This facilitates the filling of black glue during the subsequent fabrication of light-emitting devices, improves the stability of the light-emitting devices, and reduces the reflectivity of light in the visible to near-infrared band from 35% to 1%~2%, achieving a "super black silicon" effect. This enhances the light-capturing ability, thereby improving the pixel contrast of the light-emitting devices and obtaining light-emitting devices with superior luminous efficacy.

[0078] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An LED chip, characterized in that, The LED chip includes a light-emitting structure and a dimming structure located on the light-emitting structure. The light-emitting structure includes at least one light-emitting unit. The dimming structure includes a silicon isolation layer and a dimming unit. The silicon isolation layer has an isolation groove penetrating the silicon isolation layer above each light-emitting unit. At least a portion of the isolation groove is filled with a dimming unit. The silicon isolation layer includes a first sidewall and a second sidewall. The first sidewall is adjacent to the light-emitting structure, and the second sidewall is farther away from the light-emitting structure than the first sidewall. A granular protrusion-like micro / nano structure is formed on the first sidewall.

2. The LED chip according to claim 1, characterized in that, The second sidewall has a layered structure.

3. The LED chip according to claim 2, characterized in that, The contact angle between the surface of the first sidewall and the liquid is 0° to 5°.

4. The LED chip according to claim 2, characterized in that, The height of the first sidewall is 10μm~50μm.

5. The LED chip according to claim 2, characterized in that, The height of the second sidewall is 25μm~65μm.

6. The LED chip according to claim 2, characterized in that, The second sidewall is perpendicular to the side surface of the silicon isolation layer away from the light-emitting structure.

7. The LED chip according to claim 1, characterized in that, The angle between the first sidewall and the side surface of the silicon isolation layer with the light-emitting structure is an obtuse angle.

8. The LED chip according to claim 1, characterized in that, At least one of the dimming units is provided with a filter unit.

9. The LED chip according to claim 6, characterized in that, The light-emitting structure includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit distributed at intervals. The silicon isolation layer has a first isolation trench, a second isolation trench, and a third isolation trench above the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit, respectively. The first isolation trench, the second isolation trench, and the third isolation trench are filled with a first dimming unit, a second dimming unit, and a third dimming unit, respectively. The first dimming unit, the second dimming unit, and the third dimming unit are provided with a first filter unit, a second filter unit, and a third filter unit, respectively.

10. A light-emitting device, characterized in that, The light-emitting device includes a substrate, a plurality of LED chips encapsulated on the substrate, and black glue, wherein the black glue is filled between adjacent LED chips, and the LED chips are the LED chips according to any one of claims 1 to 9.

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