Micro LED packaging structure transfer method and Micro LED display device

Abstract

The invention relates to a transfer method of a Micro LED packaging structure and a Micro LED display device, and relates to the technical field of semiconductor display. According to the transfer method of the Micro LED packaging structure, the ratio of the thickness of a packaging layer subjected to planarization processing to the height of a Micro LED unit is set to be larger than 10, then four symmetrically-distributed concave cavities are formed in the packaging layer of each Micro LED packaging array, the ratio of the depth of the concave cavities to the thickness of the packaging layer is 0.3-0.5, and the ratio of the depth of the concave cavities to the thickness of the packaging layer is 0.3-0.5. The distance between every two adjacent concave cavities is 800-3000 microns, through the process steps, the large-size magnetic component can be formed, the preparation process of the magnetic component is simplified, and the magnetic attraction force of the magnetic component can be improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor light emitting technology, and in particular to a method for transferring a Micro LED packaging structure and a Micro LED display device. Background Art

[0002] Micro LED displays are a type of display technology based on arrays of micron-sized semiconductor light-emitting units. Individual units are typically under 50 microns in size and can be densely integrated on a chip. Combining the advantages of new display technologies with light-emitting diode (LED) technology, they offer self-luminescence, high efficiency, low power consumption, high integration, high stability, and 24 / 7 operation. However, the production process for Micro LEDs is complex, involving multiple high-precision and high-stability steps, such as epitaxial growth, photolithography, chip fabrication, and batch transfer. Improving transfer methods to minimize chip transfer errors, surface damage, and misalignment is a technical issue of widespread concern in the industry. Summary of the Invention

[0003] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a method for transferring a Micro LED packaging structure and a Micro LED display device.

[0004] To achieve the above objectives, the present invention proposes a method for transferring a Micro LED package structure, which includes the following steps: A semiconductor light-emitting wafer is provided, and the semiconductor light-emitting wafer is diced to form a plurality of MicroLED units. Each of the MicroLED units includes a substrate, a first semiconductor layer, a quantum well light-emitting layer, and a second semiconductor layer.

[0005] A carrier substrate is provided, wherein a surface of the carrier substrate has a plurality of first grooves arranged in an array, and a plurality of Micro LED units are respectively disposed in the corresponding first grooves, so that a portion of the substrate of each Micro LED unit is embedded in the first groove.

[0006] Then, an encapsulation layer is formed on the carrier substrate, and the encapsulation layer encapsulates the multiple Micro LED units. The carrier substrate is then peeled off and flattened to expose the first semiconductor layer of each Micro LED unit, and the ratio of the thickness of the encapsulation layer after the flattening process to the height of the Micro LED unit is greater than 10.

[0007] The encapsulation layer is then cut to form a plurality of mutually separated Micro LED encapsulation arrays, each of which includes N×N array-arranged Micro LED units, where N≥30.

[0008] Then, four symmetrically distributed cavities are formed in the packaging layer of each Micro LED packaging array, the ratio of the depth of the cavity to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns.

[0009] Then, a magnetic member is formed in the cavity. The magnetic member is a resin material containing magnetic fillers.

[0010] A transfer substrate is provided, and the Micro LED package array formed with the magnetic component is disposed on the transfer substrate.

[0011] A driving substrate is provided, and then the Micro LED package array on the transfer substrate is transferred to the driving substrate.

[0012] As a preferred technical solution, the distances between adjacent first grooves are the same.

[0013] As a preferred technical solution, the ratio of the thickness of the portion of the substrate embedded in the first groove in the substrate of each Micro LED unit to the thickness of the substrate is greater than 0.5 and less than 0.8.

[0014] As a preferred technical solution, the ratio of the thickness of the encapsulation layer after planarization to the height of the Micro LED unit is less than 20.

[0015] As a preferred technical solution, the concave cavity includes a first concave cavity, a second concave cavity, a third concave cavity and a fourth concave cavity arranged in sequence, a first magnetic component is arranged in the first concave cavity and the third concave cavity, and a second magnetic component is arranged in the second concave cavity and the fourth concave cavity.

[0016] As a preferred technical solution, the first cavity, the second cavity, the third cavity and the fourth cavity have the same size.

[0017] As a preferred technical solution, the weight percentage of the magnetic filler in the first magnetic component is greater than the weight percentage of the magnetic filler in the second magnetic component.

[0018] As a preferred technical solution, the transfer substrate has four third magnetic components. When the Micro LED package array is set on the transfer substrate, each first magnetic component and each second magnetic component are respectively adsorbed onto the corresponding third magnetic component.

[0019] As a preferred technical solution, after exposing the first semiconductor layer of each of the Micro LED units, a plurality of metal electrodes are formed on the Micro LED package array, so that each metal electrode is electrically connected to the first semiconductor layer of each corresponding Micro LED unit.

[0020] The present invention further provides a Micro LED display device, which is formed using the above-mentioned transfer method.

[0021] The beneficial effects of the present invention are: In the transfer method of the Micro LED packaging structure of the present invention, by setting the ratio of the thickness of the flattened packaging layer to the height of the Micro LED unit to be greater than 10, four symmetrically distributed cavities are formed in the packaging layer of each Micro LED packaging array, the ratio of the depth of the cavity to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns. Through the above process steps, large-scale magnetic components can be formed, simplifying the preparation process of the magnetic components and improving the magnetic attraction of the magnetic components. Furthermore, by adjusting the weight percentage of the magnetic filler in the first magnetic component to be greater than the weight percentage of the magnetic filler in the second magnetic component, and by setting the first magnetic component in the first cavity and the third cavity, and setting the second magnetic component in the second cavity and the fourth cavity, the above arrangement ensures that the Micro LED packaging array has sufficient magnetic attraction while reducing the amount of magnetic material used, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It shows a schematic diagram of the structure of scribing a light-emitting wafer to form multiple Micro LED units in an embodiment of the present invention.

[0023] Figure 2 It is a schematic structural diagram showing a plurality of Micro LED units disposed in first grooves of a carrier substrate in an embodiment of the present invention.

[0024] Figure 3 It is a schematic structural diagram of forming an encapsulation layer and performing a planarization process in an embodiment of the present invention.

[0025] Figure 4It is a schematic structural diagram showing a method of cutting the packaging layer to form a plurality of separated MicroLED packaging arrays in an embodiment of the present invention.

[0026] Figure 5 It is a schematic structural diagram of forming a cavity and forming a magnetic component in an embodiment of the present invention.

[0027] Figure 6 It shows a schematic structural diagram of disposing a Micro LED package array on a transfer substrate in an embodiment of the present invention.

[0028] Figure 7 It shows a schematic diagram of the structure of transferring the Micro LED package array on the transfer substrate to the driving substrate in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0030] like Figures 1 to 7 As shown, this embodiment provides a method for transferring a Micro LED package structure, and the method for transferring a Micro LED package structure includes the following steps: like Figure 1 As shown, a semiconductor light-emitting wafer is provided, and the semiconductor light-emitting wafer is diced to form a plurality of Micro LED units 100 . Each of the Micro LED units 100 includes a substrate 101 , a first semiconductor layer 102 , a quantum well light-emitting layer 103 , and a second semiconductor layer 104 .

[0031] In a specific embodiment, the substrate 101 is a sapphire substrate or a gallium nitride substrate, and the first semiconductor layer 102, the quantum well light-emitting layer 103 and the second semiconductor layer 104 are prepared by organic metal chemical vapor deposition, wherein the first semiconductor layer 102 and the second semiconductor layer 104 are n-type gallium nitride layers and p-type gallium nitride layers, respectively, and the quantum well light-emitting layer 103 is an alternately grown InGaN quantum well layer and GaN quantum barrier layer.

[0032] like Figure 2As shown, a carrier substrate 200 is provided, and the surface of the carrier substrate 200 has a plurality of first grooves 201 arranged in an array. A plurality of Micro LED units 100 are respectively arranged in the corresponding first grooves 201, so that a portion of the substrate 101 of each Micro LED unit 100 is embedded in the first groove 201.

[0033] In a specific embodiment, the distances between adjacent first grooves 201 are the same.

[0034] In a specific embodiment, the carrier substrate 200 is one of a ceramic substrate, a glass substrate, a metal substrate and a semiconductor substrate, and the first groove 201 is formed by a wet etching process or a dry etching process.

[0035] In a specific embodiment, a temporary adhesive material is pre-placed in each groove through a dispensing process or a slit coating process. The temporary adhesive material can lose its viscosity under light or heating conditions, and then the substrate 101 of each Micro LED unit 100 is bonded to the first groove 201 using the temporary adhesive material.

[0036] In a specific embodiment, a ratio of the thickness of the portion of the substrate 101 embedded in the first groove 201 of the substrate 101 of each Micro LED unit 100 to the thickness of the substrate 101 is greater than 0.5 and less than 0.8.

[0037] like Figure 3 As shown, an encapsulation layer 300 is then formed on the carrier substrate 200, and the encapsulation layer 300 encapsulates the multiple Micro LED units 100. The carrier substrate 200 is then peeled off and flattened to expose the first semiconductor layer 102 of each Micro LED unit 100, and the ratio of the thickness of the encapsulation layer 300 after the flattening process to the height of the Micro LED unit 100 is greater than 10.

[0038] In a specific embodiment, the ratio of the thickness of the planarized encapsulation layer 300 to the height of the Micro LED unit 100 is less than 20.

[0039] In a specific embodiment, the encapsulation layer 300 is an epoxy resin layer, and the encapsulation layer 300 is formed by a slit coating or injection molding process.

[0040] In a specific embodiment, the carrier substrate 200 is subjected to light treatment or heat treatment to make the temporary adhesive material lose its viscosity, thereby peeling off the carrier substrate 200, and then removing the substrate 101 and part of the encapsulation layer 300 by a chemical mechanical polishing process to form a flattened surface, thereby exposing the first semiconductor layer 102 of each Micro LED unit 100.

[0041] In a specific embodiment, after the first semiconductor layer 102 of each of the Micro LED units 100 is exposed, a plurality of metal electrodes 105 are respectively formed on the plurality of Micro LED units 100, so that each metal electrode 105 is electrically connected to the first semiconductor layer 102 of each corresponding Micro LED unit 100. In a more specific embodiment, the metal electrode 105 can be a metal copper electrode or a metal silver electrode.

[0042] like Figure 4 As shown, the encapsulation layer 300 is then cut to form a plurality of mutually separated MicroLED encapsulation arrays 400. Figure 4 As a schematic diagram, only one Micro LED package array 400 is shown, and each Micro LED package array 400 includes N×N array-arranged Micro LED units, where N≥30. Figure 4 Only some Micro LED units are shown schematically, and the actual number of Micro LED units in each Micro LED unit packaging module 400 shall be subject to the written description of the specific embodiment.

[0043] In a specific embodiment, a plurality of mutually separated Micro LED package arrays 400 are formed by laser cutting.

[0044] like Figure 5 As shown, Figure 5 This is a top view of the Micro LED package array 400. Four symmetrically distributed cavities are then formed in the package layer 300 of each Micro LED package array 400. The ratio of the depth of the cavity to the thickness of the package layer 300 is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns. Magnetic components are then formed in the cavities. The magnetic components are made of a resin material containing magnetic fillers.

[0045] In a specific embodiment, the concave cavity includes a first concave cavity 401, a second concave cavity 402, a third concave cavity 403 and a fourth concave cavity 404 arranged in sequence, a first magnetic component 501 is arranged in the first concave cavity 401 and the third concave cavity 403, and a second magnetic component 502 is arranged in the second concave cavity 402 and the fourth concave cavity 404.

[0046] In a specific embodiment, a portion of the first magnetic member 501 and a portion of the second magnetic member 502 protrude from the surface of the packaging layer 300 .

[0047] In a specific embodiment, four symmetrically distributed cavities are formed in the packaging layer 300 of each Micro LED package array 400 by laser ablation or mechanical cutting process.

[0048] In a specific embodiment, the first concave cavity 401 , the second concave cavity 402 , the third concave cavity 403 and the fourth concave cavity 404 have the same size.

[0049] In a specific embodiment, the magnetic filler is ferroferric oxide powder, iron-cobalt powder or iron-nickel powder, the resin material is any suitable resin material such as polyethylene, polypropylene, EVA, PVB, etc., and the first magnetic component 501 and the second magnetic component 502 are formed by a dispensing process, a slit coating process or a spraying process.

[0050] In a specific embodiment, the weight percentage of the magnetic filler in the first magnetic component 501 is greater than the weight percentage of the magnetic filler in the second magnetic component 502. More specifically, the weight percentage of the magnetic filler in the first magnetic component 501 is 2-4 wt%, and the weight percentage of the magnetic filler in the second magnetic component 502 is 5-8 wt%.

[0051] like Figure 6 As shown, a transfer substrate 600 is provided, and the Micro LED package array 400 formed with magnetic components is placed on the transfer substrate 600 .

[0052] In a specific embodiment, the transfer substrate 600 has four third magnetic components 601 . When the MicroLED package array 400 is set on the transfer substrate 600 , each first magnetic component 501 and each second magnetic component 502 are respectively adsorbed onto the corresponding third magnetic component 601 .

[0053] In a specific embodiment, four grooves are formed in a predetermined area of ​​the transfer substrate 600, and a third magnetic member 601 is formed in each of the four grooves, and the third magnetic member 601 does not fill the grooves. When the Micro LED package array 400 is set on the transfer substrate 600, a portion of the first magnetic member 501 and a portion of the second magnetic member 502 are respectively embedded in the grooves, thereby achieving magnetic adsorption.

[0054] In a specific embodiment, the third magnetic component 601 is a resin material containing magnetic filler, the magnetic filler is ferroferric oxide powder, iron cobalt powder or iron nickel powder, the resin material is any suitable resin material such as polyethylene, polypropylene, EVA, PVB, etc., and the third magnetic component 601 is formed by a dispensing process, a slit coating process or a spraying process. The weight percentage of the magnetic filler in the third magnetic component 601 is 10-15 wt%.

[0055] like Figure 7 As shown, a driving substrate 700 is provided, and then the Micro LED package array 400 on the transfer substrate 600 is moved to the driving substrate 700 .

[0056] In a specific embodiment, the metal electrode 105 is electrically connected to a corresponding pixel electrode (not shown) in the driving substrate 700 .

[0057] In a specific embodiment, after the Micro LED package array 400 on the transfer substrate 600 is moved to the driving substrate 700, the transfer substrate 600 is removed, and then an organic protective layer 800 is formed. The encapsulation layer 300 and the organic protective layer 800 are then ground to expose the second semiconductor layer 104 of each Micro LED unit 100, and then a common electrode 900 is formed.

[0058] like Figure 7 As shown, the present invention further provides a Micro LED display device, which is formed by the above-mentioned transfer method.

[0059] In another preferred technical solution, the present invention provides a method for transferring a Micro LED package structure, which includes the following steps: A semiconductor light-emitting wafer is provided, and the semiconductor light-emitting wafer is diced to form a plurality of MicroLED units. Each of the MicroLED units includes a substrate, a first semiconductor layer, a quantum well light-emitting layer, and a second semiconductor layer.

[0060] A carrier substrate is provided, wherein a surface of the carrier substrate has a plurality of first grooves arranged in an array, and a plurality of Micro LED units are respectively disposed in the corresponding first grooves, so that a portion of the substrate of each Micro LED unit is embedded in the first groove.

[0061] Then, an encapsulation layer is formed on the carrier substrate, and the encapsulation layer encapsulates the multiple Micro LED units. The carrier substrate is then peeled off and flattened to expose the first semiconductor layer of each Micro LED unit, and the ratio of the thickness of the encapsulation layer after the flattening process to the height of the Micro LED unit is greater than 10.

[0062] The encapsulation layer is then cut to form a plurality of mutually separated Micro LED encapsulation arrays, each of which includes N×N array-arranged Micro LED units, where N≥30.

[0063] Then, four symmetrically distributed cavities are formed in the packaging layer of each Micro LED packaging array, the ratio of the depth of the cavity to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns.

[0064] Then, a magnetic member is formed in the cavity. The magnetic member is a resin material containing magnetic fillers.

[0065] A transfer substrate is provided, and the Micro LED package array formed with the magnetic component is disposed on the transfer substrate.

[0066] A driving substrate is provided, and then the Micro LED package array on the transfer substrate is transferred to the driving substrate.

[0067] In other preferred technical solutions, the distances between adjacent first grooves are the same.

[0068] In other preferred technical solutions, the ratio of the thickness of the portion of the substrate embedded in the first groove in the substrate of each Micro LED unit to the thickness of the substrate is greater than 0.5 and less than 0.8.

[0069] In other preferred technical solutions, the ratio of the thickness of the encapsulation layer after planarization to the height of the Micro LED unit is less than 20.

[0070] In other preferred technical solutions, the concave cavity includes a first concave cavity, a second concave cavity, a third concave cavity and a fourth concave cavity arranged in sequence, a first magnetic component is arranged in the first concave cavity and the third concave cavity, and a second magnetic component is arranged in the second concave cavity and the fourth concave cavity.

[0071] In other preferred technical solutions, the first cavity, the second cavity, the third cavity and the fourth cavity have the same size.

[0072] In other preferred technical solutions, the weight percentage of the magnetic filler in the first magnetic component is greater than the weight percentage of the magnetic filler in the second magnetic component.

[0073] In other preferred technical solutions, the transfer substrate has four third magnetic components. When the MicroLED package array is set on the transfer substrate, each first magnetic component and each second magnetic component are respectively adsorbed onto the corresponding third magnetic component.

[0074] In other preferred technical solutions, after the first semiconductor layer of each Micro LED unit is exposed, a plurality of metal electrodes are formed on the Micro LED package array, so that each metal electrode is electrically connected to the first semiconductor layer of each corresponding Micro LED unit.

[0075] In other preferred technical solutions, the present invention further proposes a Micro LED display device, which is formed using the above-mentioned transfer method.

[0076] In the transfer method of the Micro LED packaging structure of the present invention, by setting the ratio of the thickness of the flattened packaging layer to the height of the Micro LED unit to be greater than 10, four symmetrically distributed cavities are formed in the packaging layer of each Micro LED packaging array, the ratio of the depth of the cavity to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns. Through the above process steps, large-scale magnetic components can be formed, simplifying the preparation process of the magnetic components and improving the magnetic attraction of the magnetic components. Furthermore, by adjusting the weight percentage of the magnetic filler in the first magnetic component to be greater than the weight percentage of the magnetic filler in the second magnetic component, and by setting the first magnetic component in the first cavity and the third cavity, and setting the second magnetic component in the second cavity and the fourth cavity, the above arrangement ensures that the Micro LED packaging array has sufficient magnetic attraction while reducing the amount of magnetic material used, thereby reducing costs.

[0077] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for transferring a Micro LED package structure, characterized by: The method for transferring the Micro LED package structure comprises the following steps: Providing a semiconductor light-emitting wafer, and scribing the semiconductor light-emitting wafer to form a plurality of Micro LED units, each of the Micro LED units including a substrate, a first semiconductor layer, a quantum well light-emitting layer, and a second semiconductor layer; Providing a carrier substrate having a plurality of first grooves arranged in an array on a surface of the carrier substrate, and disposing a plurality of MicroLED units in corresponding first grooves, such that a portion of the substrate of each MicroLED unit is embedded in the first groove; Next, an encapsulation layer is formed on the carrier substrate, where the encapsulation layer encapsulates the plurality of Micro LED units. The carrier substrate is then peeled off and planarized to expose the first semiconductor layer of each Micro LED unit, with the ratio of the thickness of the encapsulation layer after the planarization process to the height of the Micro LED unit being greater than 10. Then, the encapsulation layer is cut to form a plurality of mutually separated Micro LED encapsulation arrays, each of which includes N×N array-arranged Micro LED units, where N is greater than or equal to 30. Then, four symmetrically distributed cavities are formed in the packaging layer of each Micro LED packaging array, wherein the ratio of the depth of the cavities to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns to 3000 microns; Then, a magnetic member is formed in the cavity, wherein the magnetic member is a resin material containing a magnetic filler; Providing a transfer substrate, placing the Micro LED package array formed with magnetic components on the transfer substrate, A driving substrate is provided, and then the Micro LED package array on the transfer substrate is transferred to the driving substrate.

2. The method for transferring a Micro LED package structure according to claim 1, wherein: The distances between adjacent first grooves are the same.

3. The method for transferring a Micro LED package structure according to claim 1, wherein: A ratio of a thickness of a portion of the substrate of each MicroLED unit embedded in the first groove to a thickness of the substrate is greater than 0.5 and less than 0.

8.

4. The method for transferring a Micro LED package structure according to claim 1, wherein: The ratio of the thickness of the encapsulation layer after the planarization treatment to the height of the Micro LED unit is less than 20.

5. The method for transferring a Micro LED package structure according to claim 1, wherein: The concave cavity includes a first concave cavity, a second concave cavity, a third concave cavity and a fourth concave cavity arranged in sequence, a first magnetic component is arranged in the first concave cavity and the third concave cavity, and a second magnetic component is arranged in the second concave cavity and the fourth concave cavity.

6. The method for transferring a Micro LED package structure according to claim 5, wherein: The first cavity, the second cavity, the third cavity, and the fourth cavity have the same size.

7. The method for transferring a Micro LED package structure according to claim 6, wherein: The weight percentage of the magnetic filler in the first magnetic member is greater than the weight percentage of the magnetic filler in the second magnetic member.

8. The method for transferring a Micro LED package structure according to claim 5, wherein: The transfer substrate has four third magnetic components. When the Micro LED package array is placed on the transfer substrate, each of the first magnetic components and each of the second magnetic components are respectively adsorbed onto the corresponding third magnetic components.

9. The method for transferring a Micro LED package structure according to claim 1, wherein: After exposing the first semiconductor layer of each of the Micro LED units, a plurality of metal electrodes are formed on the Micro LED package array, such that each metal electrode is electrically connected to the first semiconductor layer of each corresponding Micro LED unit.

10. A Micro LED display device, characterized in that: The Micro LED display device is formed by using the transfer method of the Micro LED packaging structure according to any one of claims 1 to 9.

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