RGB three-color integrated mini-led chip, manufacturing method thereof and display panel

Abstract

The application discloses a kind of RGB three color integrated Mini-LED chip and its manufacturing method, display panel, the manufacturing method of the RGB three color integrated Mini-LED chip includes etching epitaxial wafer to obtain the epitaxial wafer of respectively containing RGB three color Mini-LED array, prepare P type reflecting electrode layer and first adhesive layer on Mini-LED array, by bonding mode sequentially three colors Mini-LED array is transferred to support substrate, deposition insulating material passivation side wall and evaporation form N type electrode.The application is etched to a certain thickness of silicon substrate, in the bonding transfer process, the silicon substrate of the Mini-LED array of later transfer will not contact the Mini-LED array that has been transferred, realize the accurate transfer of a large number of Mini-LED chip, effectively solve the problem of alignment accuracy and transfer efficiency in bonding transfer process.And in chip manufacturing process, RGB three color Mini-LED chip in single pixel can be integrated, can simplify subsequent packaging process, process is simple, reduce the manufacturing cost of Mini-LED.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light-emitting diodes, in particular to an RGB three-color integrated Mini-LED chip, a manufacturing method thereof and a display panel. BACKGROUND

[0002] Due to the rapid increase in demand for mobile phones, televisions, AR, VR and other devices, the market demand for high-performance display panels has also increased dramatically. Inorganic light-emitting diode (LED) based displays are considered to be one of the most promising center of next-generation display technologies. Like traditional LED chips used for lighting, LED chips used for display inherit the advantages of high efficiency, long life, etc. of traditional LED chips, but their size needs to be reduced to below 200um, so Mini-LED and Micro-LED are also born.

[0003] The chip size of Micro-LED is usually less than 100um, and it still faces technical challenges, so the Mini-LED chip with a size between the traditional LED chip (>200um) and the Micro-LED chip (<100um) is more easily commercialized.

[0004] In order to realize full-color display of RGB three colors, each pixel needs to contain a group of RGB micro-LEDs, but transferring such a large number of three different color micro-LEDs to the same substrate needs to consider both transfer efficiency and transfer precision, which is undoubtedly very difficult. SUMMARY

[0005] The first object of the present application is to provide a manufacturing method of an RGB three-color integrated Mini-LED chip, which can reduce the manufacturing cost of Mini-LED and simplify the subsequent packaging process.

[0006] The second object of the present application is to provide an RGB three-color integrated Mini-LED chip.

[0007] The third object of the present application is to provide a display panel.

[0008] The first object of the present application is achieved in particular as follows:

[0009] The manufacturing method of an RGB three-color integrated Mini-LED chip comprises the following steps:

[0010] S1: growing three color epitaxial layers on three silicon substrates respectively to obtain three color epitaxial wafers;

[0011] S2: performing pattern processing on the three color epitaxial wafers respectively to form three color Mini-LED arrays;

[0012] S3: evaporating to form a P-type reflective electrode layer and a first adhesive layer on the three-color Mini-LED arrays respectively;

[0013] S4: etching the silicon substrate of the non-Mini-LED mesa area of the three-color epitaxial wafers respectively;

[0014] S5: providing a silicon substrate, and evaporating to form a second adhesive layer on the surface of the silicon substrate;

[0015] S6: transferring one-color Mini-LED array to the support substrate by bonding and removing the silicon substrate;

[0016] S7: repeating step S6 twice to transfer the other two-color Mini-LED arrays to the support substrate and remove the silicon substrate respectively;

[0017] S8: etching to remove the epitaxial layer material at the edge of the three-color Mini-LED array;

[0018] S9: depositing an insulating material to form a passivation film;

[0019] S10: evaporating to form an N-type electrode;

[0020] S11: cutting the array to obtain individual RGB Mini-LED chips.

[0021] Further, in step S1, the epitaxial layer material is Al y In x Ga 1-x-y N(0≤x≤1, 0≤y≤1).

[0022] Further, in step S2, the patterned processing of the epitaxial wafer is etching through the epitaxial layer of the non-Mini-LED mesa area.

[0023] Further, in step S4, the thickness of the etched silicon substrate is 0.5-10 μm, and the etching mask is the first adhesive layer.

[0024] Further, the three epitaxial wafers obtained in step S1 are red, green and blue.

[0025] Further, any one-color Mini-LED array has the same alignment bonding mark as the other two-color Mini-LED arrays, and the bonding mark can improve the accuracy of bonding.

[0026] The second object of the application is achieved in particular as follows:

[0027] An RGB Mini-LED chip manufactured according to a manufacturing method of an RGB three-color integrated Mini-LED chip.

[0028] Preferably, the size of the RGB Mini-LED chip is 100-300 mu m.

[0029] The third object of the present application is achieved in particular as follows:

[0030] A display panel comprising the RGB Mini-LED chip provided by the present application.

[0031] Further, the RGB Mini-LED chip is encapsulated on a driving substrate after being sorted, die-bonded and wire-bonded.

[0032] The present application realizes precise transfer of a large number of Mini-LED chips by etching a certain thickness of silicon substrate, so that the silicon substrate of the Mini-LED array transferred later does not contact the Mini-LED array transferred already, effectively solving the problems of alignment accuracy and transfer efficiency in the bonding transfer process. In the manufacturing process of the Mini-LED chip, the Mini-LED array is formed by etching, and the three-color Mini-LED arrays are transferred to the support substrate in sequence by bonding. This method is simple to operate and can realize precise transfer of a large number of Mini-LED chips. In the manufacturing process of the Mini-LED chip, the integration of RGB three-color Mini-LED chips in a single pixel is realized, which simplifies the subsequent packaging process, reduces the manufacturing cost of the Mini-LED, and improves the packaging efficiency when the Mini-LED chip is encapsulated on the driving substrate after being sorted, die-bonded and wire-bonded. The distance between the single pixels R / G / B in the same chip is very small, which can realize high-density pixel display. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 An epitaxial structure of the RGB three-color integrated Mini-LED chip of the present application;

[0034] Figure 2 A schematic diagram of the RGB three-color integrated Mini-LED chip after the pattern processing to form the Mini-LED array according to an embodiment of the present application;

[0035] Figure 3 A schematic diagram of the RGB three-color integrated Mini-LED chip after evaporating the P-type emission electrode layer and the first adhesive layer according to an embodiment of the present application;

[0036] Figure 4A schematic view of etching a silicon substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0037] Figure 5 A schematic view of transferring a Mini-LED array of a first color to a support substrate and removing the substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0038] Figure 6 A top view of transferring a Mini-LED array of a first color to a support substrate and removing the substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0039] Figure 7 A schematic view of transferring a Mini-LED array of a second color to a support substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0040] Figure 8 A top view of transferring a Mini-LED array of a second color to a support substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0041] Figure 9 A schematic view of transferring a Mini-LED array of a third color to a support substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0042] Figure 10 A top view of transferring a Mini-LED array of a third color to a support substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0043] Figure 11 A schematic view of etching a silicon substrate after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0044] Figure 12 A schematic view of depositing an insulating material to form a passivation layer after an RGB three-color integrated Mini-LED chip of an embodiment of the present application.

[0045] Figure 13 A schematic view of evaporating an N-type electrode after an RGB three-color integrated Mini-LED chip of an embodiment of the present application;

[0046] Figure 14 A top view of the obtained Mini-LED chip array;

[0047] In the figure: 101-silicon substrate, 102-N-type semiconductor layer, 103-quantum well light-emitting semiconductor layer, 104-P-type semiconductor layer, 105-Mini-LED array, 106-non-Mini-LED mesa area, 201-first color epitaxial layer, 202-second color epitaxial layer, 203-third color epitaxial layer, 301-P-type reflective electrode layer, 401-first adhesive layer, 402-second adhesive layer, 501-silicon substrate, 601-insulating material, 701-N-type electrode. DETAILED DESCRIPTION

[0048] The application will be described in detail below with reference to the embodiments and with reference to the accompanying drawings.

[0049] Embodiment:

[0050] An RGB monolithic integrated Mini-LED chip, comprising the following steps:

[0051] (1) Growth of epitaxial layer: first, grow a first color epitaxial layer 201, a second color epitaxial layer 202, and a third color epitaxial layer 203 by MOCVD, provide a silicon substrate 101, and epitaxially grow an N-type semiconductor layer 102, a quantum well light-emitting semiconductor layer 103, and a P-type semiconductor layer 104 on the silicon substrate 101 in sequence, and the semiconductor layer material is Al y In x Ga 1-x-y N(0≤x≤1, 0≤y≤1), as shown in the figure; in this embodiment, a silicon substrate is selected, and no complex technology such as laser stripping needs to be used when etching and removing the silicon substrate later, so as to protect the light-emitting unit from being damaged; Figure 1

[0052] (2) Epitaxial wafer patterning: spin-coat photoresist on the surface of the first color epitaxial layer 201, the second color epitaxial layer 202, and the third color epitaxial layer 203, and perform exposure and development to expose the pattern of the Mini-LED array; etch the photoetched epitaxial wafer from the P-type semiconductor layer 104 side, and etch through the P-type semiconductor layer 104, the quantum well light-emitting semiconductor layer 103, and the N-type semiconductor layer 102 outside the non-Mini-LED array area from top to bottom; remove the photoresist by development to form a Mini-LED array 105 and a non-Mini-LED mesa area 106, as shown in the figure; Figure 2

[0053] (3) Evaporation of P-type reflective electrode layer and first adhesive layer: using the method of electron beam evaporation, evaporate the P-type reflective electrode layer 301 and the first adhesive layer 401 on the three-color Mini-LED array, as shown in the figure; Figure 3

[0054] ​​​(4) Silicon substrate etching: ICP etching method is adopted, the first adhesive layer 401 is used as a mask, the silicon substrate 101 of the non-mini LED mesa area 106 on the three-color epitaxial wafer is etched, and the etching depth is 0.5-10 μm, as shown in Figure 4 ;

[0055] (5) Bonding and removing silicon substrate: metal bonding method is adopted, the epitaxial wafer containing three-color Mini-LED array is bonded with the second adhesive layer 402 and the silicon substrate 501 in turn, and the silicon substrate 101 is removed. The method for removing the silicon substrate can be wet etching. After the first transfer, as shown in Figure 5 , Figure 6 , after the second transfer, as shown in Figure 7 , Figure 8 , and after the third transfer, as shown in Figure 9 Figure 10 . Since the silicon substrate is etched by 0.5-10 μm in step (4), the silicon substrate 101 of the Mini-LED array of the second color will not contact the transferred Mini-LED array of the first color during the second transfer. During the third transfer, the silicon substrate 101 of the Mini-LED array of the third color will not contact the transferred Mini-LED array of the first and second colors. The silicon substrates of the three-color epitaxial wafers are etched to the same depth, and the three-color Mini-LED array formed after the third transfer is isometric, which is convenient for subsequent preparation process. The silicon substrate 501 and the substrate 101 are made of the same material, and there is no thermal mismatch during bonding and transfer, which improves the precision of bonding;

[0056] (6) Edge etching: through photolithography and etching process, the epitaxial layer at the edge of the Mini-LED array is removed, the width is 10 μm, and the etching liquid can be phosphoric acid, as shown in Figure 11 ;

[0057] (7) Deposition of insulating material: insulating material is deposited on the sidewall and surface of the Mini-LED array to form a passivation film 601, and the insulating material can be SiO2, as shown in Figure 12 ;

[0058] (8) N-type electrode evaporation: electron beam evaporation method is adopted to evaporate N-type electrode 701 on the surface of N-type semiconductor layer 102 of the Mini-LED array, and the electrode material can be Cr / Pt / Au, as shown in Figure 13 ;

[0059] (9) As shown in Figure 14 , the Mini-LED chip array is cut to obtain independent RGB Mini-LED chips, and the size of the RGB Mini-LED chip is 100-300 μm.

[0060] Thus, the RGB monolithic integrated Mini-LED chip is obtained.

[0061] The embodiment also provides a display panel including the RGB Mini-LED chip prepared above. Since the Mini-LED chip has realized three-color integration in a single chip, the packaging efficiency is greatly improved after sorting, die bonding and wire bonding and packaging on a driving substrate. Moreover, the distance between single pixels R / G / B in the same chip is small, and high-density pixel display can be realized.

[0062] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing an RGB three-color integrated Mini-LED chip, characterized by: The method comprises the following steps: S1: growing three colors of epitaxial layers on three silicon substrates respectively to obtain three colors of epitaxial wafers; S2: performing patterning treatment on the three colors of epitaxial wafers respectively to form three colors of Mini-LED arrays; there are the same alignment bonding marks in any color of Mini-LED array and the other two colors of Mini-LED arrays; S3: evaporating to form a P-type reflective electrode layer and a first adhesive layer on the three colors of Mini-LED arrays respectively; S4: taking the first adhesive layer as an etching mask to etch the silicon substrate of the non-Mini-LED mesa area of the three colors of epitaxial wafers respectively; S5: providing a silicon substrate, and evaporating to form a second adhesive layer on the surface of the silicon substrate; S6: transferring one color of Mini-LED array to the support substrate by bonding and removing the silicon substrate; S7: repeating step S6 twice to transfer the other two colors of Mini-LED arrays to the support substrate and remove the silicon substrate respectively; S8: etching to remove the epitaxial layer material at the edge of the three colors of Mini-LED arrays; S9: depositing an insulating material to form a passivation film; S10: evaporating to form an N-type electrode; S11: cutting the array to obtain independent RGB Mini-LED chips. 2.The method of claim 1, wherein: In step S1, the epitaxial layer material is Al y In x Ga 1-x-y N(0≤x≤1, 0≤y≤1). 3.The method of claim 1, wherein: The colors of the three epitaxial wafers obtained in step S1 are red, green and blue. 4.The method of claim 1, wherein: In step S2, the patterning treatment on the epitaxial wafer is etching through the epitaxial layer of the non-Mini-LED mesa area. 5.The method of claim 1, wherein: In step S4, the thickness of the etched silicon substrate is 0.5-10 μm.

6. An RGB Mini-LED chip manufactured by the manufacturing method according to any one of claims 1-5.

7. The RGB Mini-LED chip of claim 6, wherein: The size of the RGB Mini-LED chip is 100-300 μm.

8. A display panel, characterized by: The RGB Mini-LED chip according to claim 7.

9. The display panel of claim 8, wherein: The RGB Mini-LED chip is packaged on a driving substrate after being sorted, die bonded and wire bonded.

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