A transfer method of a micro LED packaging structure and a micro LED display device

Abstract

The application relates to a Micro LED packaging structure transfer method and a Micro LED display device, and relates to the technical field of semiconductor display. In the Micro LED packaging structure transfer method, the ratio of the thickness of the packaging layer after planarization treatment to the height of the Micro LED unit is 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 cavities to the thickness of the packaging layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns-3000 microns. Through the above process steps, a large-size magnetic component can be formed, the preparation process of the magnetic component is simplified, and the magnetic attraction of the magnetic component can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor light-emitting technology, in particular to a transfer method of a Micro LED packaging structure and a Micro LED display device. BACKGROUND

[0002] The Micro LED display device is a display technology based on an array of micro semiconductor light-emitting units, the size of a single light-emitting unit is usually below 50 microns, and it can be integrated on a chip at high density. This technology combines the advantages of new display technology and light-emitting diode (LED) technology, and has the characteristics of self-emission, high efficiency, low power consumption, high integration, high stability and all-weather operation. The production process of Micro LED is complex, involving multiple high-precision and high-stability process steps such as epitaxial growth, photolithography, chip manufacturing, batch transfer, etc. How to improve the transfer method, reduce chip transfer errors, surface damage and misplacement, etc. is a technical problem widely concerned in the industry. SUMMARY

[0003] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a transfer method of a Micro LED packaging structure and a Micro LED display device.

[0004] To achieve the above purpose, the present application provides a transfer method of a Micro LED packaging structure, which comprises the following steps:

[0005] A semiconductor light-emitting wafer is provided, and the semiconductor light-emitting wafer is subjected to dicing treatment to form a plurality of Micro LED units, each of which comprises a substrate, a first semiconductor layer, a quantum well light-emitting layer and a second semiconductor layer.

[0006] A carrier substrate is provided, the surface of the carrier substrate has a plurality of first grooves arranged in an array, and a plurality of Micro LED units are arranged in the corresponding first grooves, so that a part of the substrate of each Micro LED unit is embedded in the first groove.

[0007] Then, a packaging layer is formed on the carrier substrate, the packaging layer encapsulates a plurality of Micro LED units, and then the carrier substrate is peeled off and subjected to planarization treatment to expose the first semiconductor layer of each Micro LED unit, and the ratio of the thickness of the planarization-treated packaging layer to the height of the Micro LED unit is greater than 10.

[0008] Then, the encapsulation layer is cut to form a plurality of mutually separated Micro LED encapsulation arrays, each of which comprises N×N arrayed Micro LED units, wherein N≥30.

[0009] Then, four symmetrically distributed cavities are formed in the encapsulation layer of each Micro LED encapsulation array, the ratio of the depth of the cavities to the thickness of the encapsulation layer is 0.3-0.5, and the spacing between adjacent cavities is 800 microns-3000 microns.

[0010] Then, a magnetic member is formed in the cavities, the magnetic member being a resin material containing magnetic filler.

[0011] A transfer substrate is provided, and the Micro LED encapsulation array with the magnetic member formed thereon is arranged on the transfer substrate.

[0012] A driving substrate is provided, and then the Micro LED encapsulation array on the transfer substrate is transferred to the driving substrate.

[0013] As a preferred technical solution, the spacing between adjacent first grooves is the same.

[0014] As a preferred technical solution, the ratio of the thickness of the portion of the substrate of each Micro LED unit embedded into the first groove to the thickness of the substrate is greater than 0.5 and less than 0.8.

[0015] 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.

[0016] As a preferred technical solution, the cavities comprise a first cavity, a second cavity, a third cavity, and a fourth cavity arranged in sequence, a first magnetic member is arranged in the first cavity and the third cavity, and a second magnetic member is arranged in the second cavity and the fourth cavity.

[0017] As a preferred technical solution, the first cavity, the second cavity, the third cavity, and the fourth cavity are the same size.

[0018] As a preferred technical solution, the weight percentage of magnetic filler in the first magnetic member is greater than the weight percentage of magnetic filler in the second magnetic member.

[0019] As a preferred technical solution, the transfer substrate has four third magnetic components, and when the Micro LED packaging array is arranged on the transfer substrate, each first magnetic component and each second magnetic component are respectively adsorbed to the corresponding third magnetic component.

[0020] As a preferred technical solution, after the first semiconductor layer of each Micro LED unit is exposed, a plurality of metal electrodes are formed on the Micro LED packaging array, so that each metal electrode is electrically connected with the first semiconductor layer of each corresponding Micro LED unit.

[0021] The application also provides a Micro LED display device formed by the above transfer method.

[0022] The application has the following advantages:

[0023] In the transfer method of the Micro LED packaging structure, by setting the ratio of the thickness of the packaging layer after planarization 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-3000 microns. Through the above process steps, a large-size magnetic component can be formed, the preparation process of the magnetic component is simplified, and the magnetic attraction of the magnetic component can be improved. Further, 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 arranging the first magnetic component in the first cavity and the third cavity, and arranging the second magnetic component in the second cavity and the fourth cavity, the above arrangement can ensure that the Micro LED packaging array has sufficient magnetic attraction while reducing the amount of magnetic material, thereby reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The structure diagram showing that the light-emitting wafer is subjected to dicing treatment to form a plurality of Micro LED units in the embodiment of the application.

[0025] Figure 2 The structure diagram showing that the plurality of Micro LED units are arranged in the first groove of the carrier substrate in the embodiment of the application.

[0026] Figure 3 The structure diagram showing that the packaging layer is formed and subjected to planarization treatment in the embodiment of the application.

[0027] Figure 4 The diagram shows a structure in an embodiment of the present invention where the encapsulation layer is cut to form multiple mutually separated MicroLED encapsulation arrays.

[0028] Figure 5 The diagram shows a structural schematic of the cavity and the magnetic component formed in an embodiment of the present invention.

[0029] Figure 6 The diagram shown is a schematic representation of a Micro LED packaging array disposed on a transfer substrate in an embodiment of the present invention.

[0030] Figure 7 The diagram shows a schematic of the structure in which the Micro LED packaging array on the transfer substrate is transferred to the driving substrate in an embodiment of the present invention. Detailed Implementation

[0031] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this 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 complete understanding of the disclosure of this application.

[0032] like Figures 1-7 As shown, this embodiment provides a method for transferring a Micro LED package structure, which includes the following steps:

[0033] 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 Micro LED unit 100 includes a substrate 101, a first semiconductor layer 102, a quantum well light-emitting layer 103, and a second semiconductor layer 104.

[0034] In a specific embodiment, the substrate 101 is a sapphire substrate or a gallium nitride substrate. The first semiconductor layer 102, the quantum well light-emitting layer 103, and the second semiconductor layer 104 are formed by metal-organic chemical vapor deposition. The first semiconductor layer 102 and the second semiconductor layer 104 are an n-type gallium nitride layer and a p-type gallium nitride layer, respectively. The quantum well light-emitting layer 103 is an alternating InGaN quantum well layer and a GaN quantum barrier layer.

[0035] like Figure 2As shown, a carrier substrate 200 is provided. 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 disposed in the corresponding first grooves 201, such that a portion of the substrate 101 of each Micro LED unit 100 is embedded in the first groove 201.

[0036] In a specific embodiment, the spacing between adjacent first grooves 201 is the same.

[0037] 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.

[0038] In a specific embodiment, a temporary adhesive material is pre-placed in each groove using a dispensing process or a slot coating process. The temporary adhesive material can lose its adhesiveness under light or heating conditions, thereby using the temporary adhesive material to bond the substrate 101 of each Micro LED unit 100 to the first groove 201.

[0039] In a specific embodiment, the ratio of the thickness of the portion of the substrate 101 embedded in the first groove 201 in each Micro LED unit 100 to the thickness of the substrate 101 is greater than 0.5 and less than 0.8.

[0040] like Figure 3 As shown, an encapsulation layer 300 is then formed on the carrier substrate 200, the encapsulation layer 300 encapsulating a plurality of Micro LED units 100. Then, the carrier substrate 200 is peeled off and planarized 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 planarization to the height of the Micro LED unit 100 is greater than 10.

[0041] 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.

[0042] In a specific embodiment, the encapsulation layer 300 is an epoxy resin layer, and the encapsulation layer 300 is formed by slot coating or injection molding process.

[0043] In specific embodiments, the carrier substrate 200 is subjected to light treatment or heat treatment, so that the temporary bonding material loses adhesion, and then the carrier substrate 200 is peeled off, and then the substrate 101 and part of the encapsulation layer 300 are removed by a chemical mechanical polishing process to form a planarized surface, thereby exposing the first semiconductor layer 102 of each Micro LED unit 100.

[0044] In specific embodiments, after the first semiconductor layer 102 of each Micro LED unit 100 is exposed, a plurality of metal electrodes 105 are formed on each Micro LED unit 100, so that each metal electrode 105 is electrically connected to the first semiconductor layer 102 of each corresponding Micro LED unit 100. In more specific embodiments, the metal electrode 105 can be a metal copper electrode or a metal silver electrode.

[0045] As shown in FIG. 4, Figure 4 The encapsulation layer 300 is then subjected to a cutting process to form a plurality of mutually separated Micro LED encapsulation arrays 400, Figure 4 As a schematic diagram, only one Micro LED encapsulation array 400 is shown, and each Micro LED encapsulation array 400 includes N×N arrayed Micro LED units, where N≥30. Figure 4 Only part of the Micro LED units are shown schematically, and the actual number of Micro LED units in each Micro LED encapsulation array 400 is as described in the specific embodiments.

[0046] In specific embodiments, a plurality of mutually separated Micro LED encapsulation arrays 400 are formed by laser cutting.

[0047] As shown in FIG. 4, Figure 5 As shown in FIG. 4, Figure 5 is a top view of the Micro LED encapsulation array 400. Four symmetrically distributed cavities are then formed in the encapsulation layer 300 of each Micro LED encapsulation array 400, the ratio of the depth of the cavities to the thickness of the encapsulation layer 300 is 0.3-0.5, and the spacing between adjacent cavities is 800 microns-3000 microns. A magnetic member is then formed in the cavities, which is a resin material containing magnetic filler.

[0048] In a specific embodiment, the cavity includes a first cavity 401, a second cavity 402, a third cavity 403, and a fourth cavity 404 arranged sequentially. A first magnetic component 501 is arranged in the first cavity 401 and the third cavity 403, and a second magnetic component 502 is arranged in the second cavity 402 and the fourth cavity 404.

[0049] In a specific embodiment, a portion of the first magnetic component 501 and a portion of the second magnetic component 502 protrude from the surface of the encapsulation layer 300.

[0050] In a specific embodiment, four symmetrically distributed cavities are formed in the encapsulation layer 300 of each Micro LED encapsulation array 400 by laser ablation or mechanical cutting processes.

[0051] In a specific embodiment, the first cavity 401, the second cavity 402, the third cavity 403, and the fourth cavity 404 have the same size.

[0052] In a specific embodiment, the magnetic filler is iron(III) oxide powder, iron-cobalt powder, or iron-nickel powder, and the resin material is any suitable resin material such as polyethylene, polypropylene, EVA, or PVB. The first magnetic component 501 and the second magnetic component 502 are formed by dispensing, slit coating, or spraying.

[0053] In a specific embodiment, the weight percentage of magnetic filler in the first magnetic component 501 is greater than the weight percentage of magnetic filler in the second magnetic component 502. More specifically, the weight percentage of magnetic filler in the first magnetic component 501 is 2-4 wt%, and the weight percentage of magnetic filler in the second magnetic component 502 is 5-8 wt%.

[0054] like Figure 6 As shown, a transfer substrate 600 is provided, on which the Micro LED package array 400 with magnetic components is disposed.

[0055] In a specific embodiment, the transfer substrate 600 has four third magnetic components 601. When the MicroLED packaging array 400 is disposed on the transfer substrate 600, each of the first magnetic components 501 and each of the second magnetic components 502 are respectively attracted to the corresponding third magnetic component 601.

[0056] In a specific embodiment, four trenches are formed in a predetermined area of ​​the transfer substrate 600, and a third magnetic member 601 is formed in each of the four trenches, such that the third magnetic member 601 does not fill the trenches. When the Micro LED packaging array 400 is disposed 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 trenches, thereby achieving magnetic adsorption.

[0057] In a specific embodiment, the third magnetic component 601 is a resin material containing magnetic filler, wherein the magnetic filler is iron oxide powder, iron-cobalt powder, or iron-nickel powder, and the resin material is any suitable resin material such as polyethylene, polypropylene, EVA, or PVB. The third magnetic component 601 is formed by dispensing, slot coating, or spraying, and the weight percentage of the magnetic filler in the third magnetic component 601 is 10-15 wt%.

[0058] 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.

[0059] In a specific embodiment, the metal electrode 105 is electrically connected to the corresponding pixel electrode (not shown) in the driving substrate 700.

[0060] 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. Next, the package layer 300 and the organic protective layer 800 are polished to expose the second semiconductor layer 104 of each Micro LED unit 100, and then a common electrode 900 is formed.

[0061] like Figure 7 As shown, the present invention also proposes a Micro LED display device, which is formed using the above-described transfer method.

[0062] In other preferred technical solutions, the present invention proposes a method for transferring a Micro LED packaging structure, the method comprising the following steps:

[0063] 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 including a substrate, a first semiconductor layer, a quantum well light-emitting layer and a second semiconductor layer.

[0064] A carrier substrate is provided, and a plurality of first grooves arranged in an array are formed on a surface of the carrier substrate. A plurality of Micro LED units are arranged in the corresponding first grooves, so that a part of the substrate of each Micro LED unit is embedded in the first groove.

[0065] Then, a packaging layer is formed on the carrier substrate, the packaging layer encapsulates a plurality of Micro LED units, and then the carrier substrate is peeled off and planarized to expose the first semiconductor layer of each Micro LED unit, and the ratio of the thickness of the packaging layer after planarization to the height of the Micro LED unit is greater than 10.

[0066] Then, the packaging layer is cut to form a plurality of mutually separated Micro LED packaging arrays, each of which includes N×N arrayed Micro LED units, where N≥30.

[0067] 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 800-3000 microns.

[0068] Then, a magnetic member is formed in the cavity, and the magnetic member is a resin material containing magnetic filler.

[0069] A transfer substrate is provided, and the Micro LED packaging array with the magnetic member formed thereon is arranged on the transfer substrate.

[0070] A driving substrate is provided, and then the Micro LED packaging array on the transfer substrate is transferred to the driving substrate.

[0071] In other preferred technical solutions, the spacing between adjacent first grooves is the same.

[0072] In other preferred technical solutions, the ratio of the thickness of the part of the substrate embedded in the first groove to the thickness of the substrate of each Micro LED unit is greater than 0.5 and less than 0.8.

[0073] In other preferred technical solutions, the ratio of the thickness of the packaging layer after planarization to the height of the Micro LED unit is less than 20.

[0074] In other preferable technical solutions, the cavities include a first cavity, a second cavity, a third cavity and a fourth cavity arranged in sequence, the first magnetic member is arranged in the first cavity and the third cavity, and the second magnetic member is arranged in the second cavity and the fourth cavity.

[0075] In other preferable technical solutions, the first cavity, the second cavity, the third cavity and the fourth cavity have the same size.

[0076] In other preferable technical solutions, 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.

[0077] In other preferable technical solutions, the transfer substrate has four third magnetic members, and when the Micro LED packaging array is arranged on the transfer substrate, each first magnetic member and each second magnetic member is respectively adsorbed to the corresponding third magnetic member.

[0078] In other preferable 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 packaging array, so that each metal electrode is electrically connected to the first semiconductor layer of each corresponding Micro LED unit.

[0079] In other preferable technical solutions, the application further provides a Micro LED display device formed by the above transfer method.

[0080] In the transfer method of the Micro LED packaging structure of the application, by setting the ratio of the thickness of the packaging layer after planarization 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 800-3000 microns. Through the above process steps, a large-size magnetic member can be formed, the preparation process of the magnetic member is simplified, and the magnetic attraction force of the magnetic member can be improved. Further, by adjusting the weight percentage of the magnetic filler in the first magnetic member to be greater than the weight percentage of the magnetic filler in the second magnetic member, and by arranging the first magnetic member in the first cavity and the third cavity and the second magnetic member in the second cavity and the fourth cavity, the above arrangement can ensure that the Micro LED packaging array has sufficient magnetic attraction while reducing the amount of magnetic material, thereby reducing the cost.

[0081] The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. A method for transferring a Micro LED packaging structure, characterized in that: The method for transferring the Micro LED packaging structure includes the following steps: A semiconductor light-emitting wafer is provided, and the semiconductor light-emitting wafer is diced 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; A carrier substrate is provided, the surface of which has a plurality of first grooves arranged in an array, and a plurality of MicroLED units are respectively disposed in the 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, the encapsulation layer encapsulating a plurality of Micro LED units. Then, the carrier substrate is peeled off and planarized to expose the first semiconductor layer of each Micro LED unit, and the ratio of the thickness of the encapsulation layer after planarization to the height of the Micro LED unit is greater than 10. Next, the encapsulation layer is cut to form multiple mutually separated Micro LED encapsulation arrays. Each Micro LED encapsulation array includes N×N Micro LED units arranged in an array, where N≥30. Next, four symmetrically distributed cavities are formed in the encapsulation layer of each Micro LED encapsulation array. The ratio of the depth of the cavity to the thickness of the encapsulation layer is 0.3-0.5, and the spacing between adjacent cavities is 800 micrometers-3000 micrometers. Next, a magnetic component is formed in the cavity, the magnetic component being a resin material containing magnetic filler; A transfer substrate is provided on which the Micro LED package array, on which magnetic components are formed, is disposed. 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 the Micro LED packaging structure according to claim 1, characterized in that: The spacing between adjacent first grooves is the same.

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

8.

4. The method for transferring the Micro LED packaging structure according to claim 1, characterized in that: The ratio of the thickness of the encapsulation layer after planarization to the height of the Micro LED unit is less than 20.

5. The method for transferring the Micro LED packaging structure according to claim 1, characterized in that: The cavity includes a first cavity, a second cavity, a third cavity, and a fourth cavity arranged sequentially. A first magnetic component is arranged in the first cavity and the third cavity, and a second magnetic component is arranged in the second cavity and the fourth cavity.

6. The method for transferring the Micro LED packaging structure according to claim 5, characterized in that: The first cavity, the second cavity, the third cavity, and the fourth cavity have the same size.

7. The method for transferring the Micro LED packaging structure according to claim 6, characterized in that: The weight percentage of magnetic filler in the first magnetic component is greater than the weight percentage of magnetic filler in the second magnetic component.

8. The method for transferring the Micro LED packaging structure according to claim 5, characterized in that: The transfer substrate has four third magnetic components. When the Micro LED packaging array is disposed on the transfer substrate, each of the first magnetic components and each of the second magnetic components is attracted to the corresponding third magnetic component.

9. The method for transferring the Micro LED packaging structure according to claim 1, characterized in that: After exposing the first semiconductor layer of each Micro LED unit, 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 the corresponding Micro LED unit.

10. A Micro LED display device, characterized in that, The Micro LED display device is formed using the transfer method of the Micro LED packaging structure as described in any one of claims 1-9.

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