Miniature light emitting diode array device and preparation method thereof

Abstract

The invention discloses a miniature light emitting diode array device and a preparation method thereof. The device comprises a driving circuit layer and a dielectric layer arranged above the driving circuit layer, a plurality of columns of light-emitting array strips are arranged in the dielectric layer, and each column of light-emitting array strip comprises a P-type electrode layer and a plurality of light-emitting units arranged on the P-type electrode layer one by one; each light-emitting unit comprises a light-emitting layer and an N-type electrode layer arranged above the light-emitting layer; the N-type electrode layer is connected with the driving circuit layer through an N-type through hole, and the P-type electrode layer is connected with the driving circuit layer through a P-type through hole. The technical problems that in the prior art, preparation is high in technical difficulty and cost, a semiconductor technological method is not suitable for being adopted, and mass production of devices is difficult to achieve are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of LED chips, and particularly to a micro light-emitting diode array device and a preparation method thereof. Background Art

[0002] Micro light-emitting diodes (LEDs) arrays have advantages such as high color saturation, high contrast, fast response speed, low power consumption, and long service life.

[0003] Currently, there are two structures for micro light-emitting diode arrays, namely vertical and flip-chip types. However, for the vertical structure of the light-emitting diode array, light output needs to be carried out through the bottom or side, which limits the selectivity of the light-emitting direction. Moreover, since light needs to be transmitted through the material interfaces between multiple layers in the vertical structure, it leads to an increase in light loss and reflection, thereby reducing the light extraction efficiency. At the same time, the preparation process of the vertical structure is relatively complex and requires multiple deposition and processing steps between different layers, increasing the technical difficulty and cost of preparation. In the flip-chip structure, the light-emitting diode chips are flip-chip bonded to the heat dissipation substrate, which makes heat management difficult. And due to the lack of direct contact between the optoelectronic chips and the heat dissipation substrate, the heat conduction and dissipation efficiency are limited, easily leading to overheating of the chips and a decline in performance. At the same time, the electrical connection in the flip-chip structure needs to be carried out through gold wires or micro solder joints, which increases the complexity of the manufacturing process and the problems of the vulnerability and reliability of the electrical connection. In addition, the light output in the flip-chip structure is mainly carried out at the bottom of the chip, and the light output direction is limited, making it difficult to achieve multi-directional light output.

[0004] Therefore, there is an urgent need for a micro light-emitting diode array device that can reduce the technical difficulty and cost of preparation and is more suitable for realizing mass production of devices using semiconductor process methods. Summary of the Invention

[0005] The present invention provides a micro light-emitting diode array device and a preparation method thereof to solve the technical problems in the prior art, such as large technical difficulty and cost in preparation, not being suitable for using semiconductor process methods, and being difficult to achieve mass production of devices.

[0006] To solve the above technical problems, an embodiment of the present invention provides a micro light-emitting diode array device, including: a driving circuit layer and a dielectric layer disposed above the driving circuit layer;

[0007] A plurality of columns of light-emitting array bands are disposed in the dielectric layer. Each column of the light-emitting array band includes a P-type electrode layer and a plurality of light-emitting units arranged one by one on the P-type electrode layer; each light-emitting unit includes a light-emitting layer and an N-type electrode layer disposed above the light-emitting layer;

[0008] The N-type electrode layer is connected to the driving circuit layer through an N-type through-hole, and the P-type electrode layer is connected to the driving circuit layer through a P-type through-hole.

[0009] As a preferred solution, the light-emitting array bands are uniformly arrayed and distributed in the dielectric layer.

[0010] As a preferred solution, the P-type electrode layer and the light-emitting layer on the P-type electrode layer are both disposed within the dielectric layer, and the N-type electrode layer is disposed outside the dielectric layer.

[0011] As a preferred solution, there is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

[0012] As a preferred solution, the N-type electrode layer is connected to an N contact pad disposed in the driving circuit layer through the N-type through-hole; each N-type through-hole is connected to a corresponding N contact pad.

[0013] As a preferred solution, the P-type electrode layer is connected to a P contact pad disposed in the driving circuit layer through the P-type through-hole; each P-type through-hole is connected to a corresponding P contact pad, and each light-emitting array band is provided with only one corresponding P-type through-hole and the P contact pad connected thereto.

[0014] Correspondingly, the present invention further provides a method for manufacturing a micro light-emitting diode array device for manufacturing the micro light-emitting diode array device as described in any one of the above, including:

[0015] Growing a gallium nitride substrate, a dielectric layer, an N-type gallium nitride, a multi-layer quantum well, and a P-type gallium nitride on a silicon substrate in sequence to obtain a light-emitting diode epitaxial wafer; wherein, the multi-layer quantum well is a light-emitting layer;

[0016] Fabricating a light-emitting array on the light-emitting diode epitaxial wafer and using a silicon-based CMOS wafer as a driving circuit; wherein, P-type contact pads and N-type contact pads are disposed on the silicon-based CMOS wafer, and the light-emitting array includes a plurality of columns of light-emitting array bands;

[0017] In the light-emitting array, the common anode and each cathode of the light-emitting array bands in the same row are independently connected to the driving circuit through corresponding through-holes until all rows of light-emitting array bands are connected to the driving circuit;

[0018] Connecting the light-emitting diode epitaxial wafer and the driving circuit through hybrid bonding, thereby realizing the combination of the P-type through-hole of the common anode and the P contact pad of the driving circuit;

[0019] After wafer bonding, fabricating the N-type through-hole metal of each cathode to be connected to the driving circuit, and fabricating an N-type electrode layer;

[0020] Fill the dielectric layer to complete the fabrication of the micro light-emitting diode array device.

[0021] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0022] The technical solution of the present invention adopts the structure of a micro light-emitting diode array device. By arranging multiple columns of light-emitting array bands in the dielectric layer, each column includes multiple light-emitting units, enabling the device to integrate a large number of light-emitting units in a smaller space, thereby achieving high integration and miniaturization, and being suitable for application scenarios requiring high-density light emission. At the same time, each light-emitting array band adopts a structure of light-emitting units arranged one by one, and adjacent units are isolated by the dielectric layer. The entire column of light-emitting units can be fabricated at one time, thus improving the production efficiency. And through the through-hole connection with the driving circuit layer, the device assembly process can also be simplified, further improving the production efficiency, reducing the technical difficulty and cost of fabrication, and being suitable for mass production of the device using semiconductor process methods.

[0023] Furthermore, each light-emitting unit is composed of an independent light-emitting layer and an N-type electrode layer, and is connected to the driving circuit layer through an N-type through-hole, enabling each light-emitting unit to be independently controlled, realizing precise adjustment of the current and light emission of each unit, providing flexibility. At the same time, the N-type through-hole and the P-type through-hole improve the current injection efficiency, avoid current loss and leakage, and improve the brightness and efficiency of the light-emitting unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : The front cross-sectional view and side cross-sectional view of a micro light-emitting diode array device provided by an embodiment of the present invention;

[0025] Figure 2 : The front cross-sectional view and side cross-sectional view of the through-hole in the micro light-emitting diode array device provided by an embodiment of the present invention;

[0026] Figure 3 : The step flow chart of a method for fabricating a micro light-emitting diode array device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1

[0029] Please refer to Figure 1, a micro - light - emitting diode array device provided by an embodiment of the present invention, includes: a driving circuit layer and a dielectric layer disposed above the driving circuit layer.

[0030] In this embodiment, please refer to Figure 2 , the function of the driving circuit layer in the LED chip is to control the current and voltage of the LED chip, ensure its normal operation and stability, provide reverse - current protection, and have functions such as brightness adjustment and dimming control.

[0031] It should be noted that the dielectric layer, as an electrical isolation and optical isolation layer, is used to achieve electrical isolation between the micro - light - emitting diode arrays and between the electrodes, and also to achieve optical and electrical isolation for each light - emitting layer.

[0032] A plurality of columns of light - emitting array bands are provided in the dielectric layer. Each column of the light - emitting array band includes a P - type electrode layer and a plurality of light - emitting units arranged one by one on the P - type electrode layer; each light - emitting unit includes a light - emitting layer and an N - type electrode layer disposed above the light - emitting layer.

[0033] As a preferred solution of this embodiment, the light - emitting array bands are uniformly array - distributed in the dielectric layer.

[0034] As a preferred solution of this embodiment, the P - type electrode layer and the light - emitting layer on the P - type electrode layer are both disposed within the dielectric layer, and the N - type electrode layer is disposed outside the dielectric layer.

[0035] As a preferred solution of this embodiment, there is a gap between the P - type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

[0036] In this embodiment, the light - emitting array bands are uniformly array - distributed in the dielectric layer, which can achieve a more uniform light output, so that the brightness uniformity of the LED device can be improved, and the light output is more balanced and consistent. And each column of the light - emitting array band is composed of a plurality of light - emitting units arranged one by one, and each light - emitting unit includes a light - emitting layer and an N - type electrode layer. Through a highly integrated design, more light - emitting units can be realized, and the brightness output of the LED device can be improved.

[0037] Furthermore, the P - type electrode layer and the light - emitting layer are disposed inside the dielectric layer, while the N - type electrode layer is disposed outside the dielectric layer, so as to achieve electrical isolation, prevent current from generating a short - circuit inside the device, and improve the stability and reliability of the device. And there is a gap between the P - type electrode layer and the driving circuit layer, and this gap is filled with the dielectric layer, which can simplify the manufacturing process, reduce the manufacturing steps and material usage, and reduce the manufacturing cost.

[0038] In this embodiment, the light-emitting unit is designed such that the light-emitting layer is located above the N-type electrode layer. This design can effectively improve the light transmission efficiency and transmittance performance. By optimizing the optical performance, the brightness and light output effect of the LED device can be improved.

[0039] In this embodiment, the thickness parameters between the layers belong to specific process parameters and can be adjusted according to the size and requirements of different LED array devices.

[0040] The N-type electrode layer is connected to the drive circuit layer through an N-type through hole, and the P-type electrode layer is connected to the drive circuit layer through a P-type through hole.

[0041] As a preferred solution of this embodiment, the N-type electrode layer is connected to the N contact pad disposed in the drive circuit layer through the N-type through hole; each N-type through hole is connected to a corresponding N contact pad.

[0042] As a preferred solution of this embodiment, the P-type electrode layer is connected to the P contact pad disposed in the drive circuit layer through the P-type through hole; each P-type through hole is connected to a corresponding P contact pad, and only one corresponding P-type through hole and its connected P contact pad are provided for each light-emitting array strip.

[0043] In this embodiment, the N electrode is a transparent electrode and uses indium tin oxide (ITO) material; the P-type electrode can use metal electrode materials such as ITO, nickel, gold, indium, and copper.

[0044] In this embodiment, different electrodes are connected to the corresponding contact pads through their corresponding through holes, thereby realizing the connection of the P-type electrode layer and / or the N-type electrode layer to the drive circuit layer, ensuring that the drive circuit layer can control the P-type electrode layer and / or the N-type electrode layer, and further realizing functions such as brightness adjustment and dimming control of the light-emitting layer.

[0045] It can be understood that the micro light-emitting diode array device in this embodiment adopts a compact structural design, tightly combines the drive circuit layer, the dielectric layer, and the light-emitting array strip, can realize the light weight and miniaturization of the device, and make it suitable for various miniaturized applications. At the same time, the light-emitting array strip is composed of several columns of light-emitting units, each light-emitting unit includes a P-type electrode layer and an N-type electrode layer, and by arranging the light-emitting units one by one, a high integration degree of multiple light-emitting units can be achieved in a limited space, improving the light-emitting density and function of the device.

[0046] By connecting the N-type electrode layer and the P-type electrode layer to the driving circuit layer through N-type vias and P-type vias, effective current transmission can be achieved, ensuring that the current can accurately flow into the light-emitting unit, improving the current injection efficiency and stability of the device. And each light-emitting unit includes a light-emitting layer and an N-type electrode layer disposed above it, so that efficient light transmission and low light loss can be achieved. At the same time, the setting of the dielectric layer can provide optical isolation, prevent light reflection and transmission, and improve the light output efficiency and brightness of the device. The preparation of the driving circuit layer, the dielectric layer and the light-emitting array strip is relatively independent, and different process parameters and material selections can be used for preparation. This flexibility can be optimized and designed according to specific requirements, improving the performance and adaptability of the device.

[0047] Implementing the above embodiments has the following effects:

[0048] The technical solution of the present invention adopts a micro light-emitting diode array device structure. By arranging multiple columns of light-emitting array strips in the dielectric layer, each column includes multiple light-emitting units, so that the device can integrate a large number of light-emitting units in a small space, thus achieving high integration and miniaturization, and is suitable for application scenarios that require high-density light emission. At the same time, each light-emitting array strip adopts a structure of light-emitting units arranged one by one, and adjacent units are isolated by the dielectric layer. The entire column of light-emitting units can be prepared at one time, thereby improving the production efficiency. And through the via connection with the driving circuit layer, the assembly process of the device can also be simplified, further improving the production efficiency, reducing the technical difficulty and cost of preparation, and is suitable for mass production of the device using semiconductor process methods.

[0049] Embodiment 2

[0050] Please refer to Figure 3 , which is a preparation method of a micro light-emitting diode array device provided by the present invention, used to prepare the micro light-emitting diode array device as described in Embodiment 1 above, and includes the following steps S101-S106:

[0051] S101: Grow a gallium nitride substrate, a dielectric layer, N-type gallium nitride, multiple quantum wells and P-type gallium nitride on a silicon substrate in sequence to obtain a light-emitting diode epitaxial wafer; wherein, the multiple quantum wells are light-emitting layers.

[0052] In this embodiment, a three-dimensional via connection method is adopted to connect the light-emitting diode array to the driving circuit. A light-emitting diode epitaxial wafer obtained by growing a gallium nitride substrate, a buffer layer, N-type gallium nitride, multiple quantum wells, and P-type gallium nitride on a silicon substrate in sequence, and a light-emitting array is fabricated on the epitaxial wafer.

[0053] S102: Fabricate a light-emitting array on the light-emitting diode epitaxial wafer, and use a silicon-based CMOS wafer as the driving circuit; wherein, a P-type contact pad and an N-type contact pad are provided on the silicon-based CMOS wafer, and the light-emitting array includes a plurality of columns of light-emitting array bands.

[0054] In this embodiment, a silicon-based CMOS wafer is used as the driving circuit, and P-type and N-type contact pads are fabricated on this wafer.

[0055] S103: In the light-emitting array, connect the common anode and each cathode of the light-emitting array bands in the same row to the driving circuit independently through corresponding vias until all the light-emitting array bands in all rows are connected to the driving circuit.

[0056] In this embodiment, the common anode (P) and each cathode (N) of the light-emitting diode unit array in the same row are independently connected to the driving circuit through corresponding vias.

[0057] S104: Connect the light-emitting diode epitaxial wafer and the driving circuit through hybrid bonding, so as to realize the combination of the P-type via of the common anode and the P-contact pad of the driving circuit.

[0058] In this embodiment, the combination of the light-emitting diode wafer and the driving circuit wafer is realized through hybrid bonding, and at the same time, the combination of the P-type via of the common anode and the P-contact pad of the driving circuit is realized.

[0059] S105: After wafer bonding, fabricate the N-type via metal of each cathode to be connected to the driving circuit, and fabricate an N-type electrode layer.

[0060] In this embodiment, after wafer bonding, fabricate the N-type via metal to be connected to the driving circuit, and fabricate an N-type transparent electrode.

[0061] S106: Fill the dielectric layer, thereby completing the preparation of the micro light-emitting diode array device.

[0062] In this embodiment, the dielectric layer serves as an electrical isolation and optical isolation layer, which is used to achieve electrical isolation between micro light-emitting diode arrays and between each electrode, and also to achieve optical and electrical isolation for each light-emitting layer.

[0063] It can be understood that in this embodiment, a gallium nitride substrate, a buffer layer, an N-type gallium nitride, multiple quantum wells, and a P-type gallium nitride are grown on a silicon substrate, and then a light-emitting array is fabricated, which can achieve a high-quality light-emitting diode structure, improve the performance and efficiency of the device. At the same time, a silicon-based CMOS wafer is used as the substrate of the driving circuit to fabricate P-type and N-type contact pads. This method can realize the integration of the driving circuit and the light-emitting diode on the same wafer, simplify the preparation process, and reduce the manufacturing cost. And in the light-emitting diode unit array, the units in the same row share a common anode (P-type), and each cathode (N-type) is independently connected to the driving circuit through a via hole, which can reduce the complexity of the device, save space, and improve the preparation efficiency. At the same time, the light-emitting diode wafer and the driving circuit wafer are combined by means of hybrid bonding to realize the combination of the P-type via hole of the common anode and the N contact pad of the driving circuit, and reliable device connection and good current transmission can be achieved, improving the reliability and performance of the device. After wafer bonding, an N-type via metal is fabricated to connect to the driving circuit, and an N-type transparent electrode is fabricated, which can achieve good current distribution and light transmission, improving the efficiency and brightness of the device. Finally, a dielectric layer is used as the electrical isolation and optical isolation layer, which can prevent the mutual interference of current and light, improving the performance and reliability of the device.

[0064] Implementing the above embodiments has the following effects:

[0065] The technical solution of the present invention adopts a micro light-emitting diode array device structure. By arranging multiple columns of light-emitting array bands in the dielectric layer, each column includes multiple light-emitting units, enabling the device to integrate a large number of light-emitting units in a smaller space, thereby achieving high integration and miniaturization, and being suitable for application scenarios requiring high-density light emission. At the same time, each light-emitting array band adopts a light-emitting unit structure arranged one by one, and adjacent units are isolated by the dielectric layer. The entire column of light-emitting units can be fabricated at one time, thus improving the production efficiency. And through the via connection with the driving circuit layer, the device assembly process can also be simplified, further improving the production efficiency, reducing the technical difficulty and cost of preparation, and being suitable for mass production of the device using semiconductor process methods.

[0066] The above specific embodiments have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A micro light-emitting diode array device, characterized in that, comprising: a driving circuit layer and a dielectric layer disposed above the driving circuit layer; a plurality of columns of light-emitting array bands are disposed in the dielectric layer, and each column of the light-emitting array bands includes a P-type electrode layer and a plurality of light-emitting units arranged one by one on the P-type electrode layer; each light-emitting unit includes a light-emitting layer and an N-type electrode layer disposed above the light-emitting layer; the N-type electrode layer is connected to the driving circuit layer through an N-type through hole, and the P-type electrode layer is connected to the driving circuit layer through a P-type through hole.

2. A micro light-emitting diode array device according to claim 1, characterized in that, the light-emitting array bands are uniformly arrayed and distributed in the dielectric layer.

3. A micro light-emitting diode array device according to claim 1, characterized in that, the P-type electrode layer and the light-emitting layer on the P-type electrode layer are both disposed within the dielectric layer, and the N-type electrode layer is disposed outside the dielectric layer.

4. A micro light-emitting diode array device according to claim 3, characterized in that, there is a gap between the P-type electrode layer and the driving circuit layer, and the gap is filled with the dielectric layer.

5. A micro light-emitting diode array device according to any one of claims 1-4, characterized in that, the N-type electrode layer is connected to an N contact pad disposed in the driving circuit layer through the N-type through hole; each N-type through hole is connected to a corresponding N contact pad.

6. A micro light-emitting diode array device according to any one of claims 1-4, characterized in that, the P-type electrode layer is connected to a P contact pad disposed in the driving circuit layer through the P-type through hole; each P-type through hole is connected to a corresponding P contact pad, and each light-emitting array band is provided with only one corresponding P-type through hole and the P contact pad connected thereto.

7. A method for manufacturing a micro light-emitting diode array device, characterized in that, for manufacturing the micro light-emitting diode array device according to any one of claims 1-6, comprising: growing a gallium nitride substrate, a dielectric layer, an N-type gallium nitride, a multi-layer quantum well and a P-type gallium nitride on a silicon substrate in sequence to obtain a light-emitting diode epitaxial wafer; wherein, the multi-layer quantum well is a light-emitting layer; fabricating a light-emitting array on the light-emitting diode epitaxial wafer and using a silicon-based CMOS wafer as a driving circuit; wherein, a P-type contact pad and an N-type contact pad are disposed on the silicon-based CMOS wafer, and the light-emitting array includes a plurality of columns of light-emitting array bands; in the light-emitting array, connecting the common anode and each cathode of the light-emitting array bands in the same row to the driving circuit independently through corresponding through holes until all rows of the light-emitting array bands are connected to the driving circuit; connecting the light-emitting diode epitaxial wafer to the driving circuit through hybrid bonding, thereby realizing the combination of the P-type through hole of the common anode and the P contact pad of the driving circuit; after wafer bonding, fabricating the N-type through hole metal of each cathode to be connected to the driving circuit and fabricating the N-type electrode layer; filling the dielectric layer, thereby completing the manufacturing of the micro light-emitting diode array device.

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