Monolithic integrated large-area multi-color high-resolution display micro-led chip and manufacturing method thereof

Abstract

The application provides a monolithic integrated large-area multi-color high-resolution display Micro-LED chip and a manufacturing method thereof. The Micro-LED chip comprises a first LED chip array and a second LED chip array arranged in layers, the first LED chip array comprises a plurality of first LED chips in a normal structure, and the second LED chip array comprises a plurality of second LED chips in a flip structure; a driving array is arranged between the first LED chip array and the second LED chip array, the driving array comprises a plurality of driving units, the driving units are integrated in pixel positions of the Micro-LED chip, and each first LED chip and each second LED chip are electrically connected to a corresponding driving unit. The application reduces the distance between LED chips by alternating arrangement of normal and flip chips, improves the resolution of the display screen, and thus makes the display effect better and more delicate.

Description

Technical Field

[0001] This invention relates to semiconductor device structures and fabrication methods, such as monolithically integrated multicolor Micro-LED display device structures and fabrication methods. Background Technology

[0002] Active-matrix liquid crystal displays (LCDs) and organic light-emitting diode (OLEDs) displays, combined with thin-film transistor (TFT) technology, are becoming increasingly popular in today's commercial electronic devices. These displays are widely used in laptops, smartphones, and personal digital assistants. Millions of pixels work together to create images on the display. TFTs act as switches to individually turn each pixel on and off, thus brightening or dimming the pixel, allowing for convenient and efficient control of each pixel and the entire display.

[0003] However, conventional LCD displays suffer from low light efficiency, resulting in high power consumption and limited battery life. Organic light-emitting diodes (OLEDs) face problems such as low reliability and screen burn-in.

[0004] Micro-LED displays utilize micrometer-sized (typically less than 50µm) inorganic LED devices as light-emitting pixels to achieve active-matrix display. From a technical perspective, Micro-LED, along with Organic Light-Emitting Diodes (OLEDs) and Quantum Dot Light-Emitting Diodes (QLEDs), belongs to the active-matrix display technology category. However, unlike OLEDs and QLEDs, Micro-LED displays offer superior luminous performance and long lifespan; their industrialization primarily faces challenges related to integration processes and related materials.

[0005] However, integrating thousands or even millions of micro-LEDs with pixel driver circuit arrays is extremely challenging. Various fabrication methods have been proposed. One method involves fabricating control circuitry on one substrate and LEDs on a separate substrate. The LEDs are then transferred to an intermediate substrate, and the original substrate is removed. The LEDs on the intermediate substrate are then picked up, and the control circuitry places them onto the substrate one at a time or several at a time. However, this fabrication process is inefficient and costly. Furthermore, existing manufacturing tools for the large-scale transfer of micro-LEDs do not exist. This invention relates to semiconductor device structures and fabrication methods thereof, providing a solution to the aforementioned problems. Summary of the Invention

[0006] The main objective of this invention is to provide a Micro-LED chip for large-area multi-color high-resolution display with chip integration and its manufacturing method, so as to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] This invention provides a single-chip integrated large-area multi-color high-resolution Micro-LED chip, comprising:

[0009] A first LED chip array and a second LED chip array are stacked together. The first LED chip array includes a plurality of first LED chips with upright structure, and the second LED chip array includes a plurality of second LED chips with flip-chip structure.

[0010] A driving array is disposed between the first LED chip array and the second LED chip array. The driving array includes multiple driving units, which are integrated in the pixel position of the Micro-LED chip. Each first LED chip and each second LED chip are electrically connected to a corresponding driving unit.

[0011] This invention also provides a method for fabricating a single-chip integrated large-area multi-color high-resolution Micro-LED chip, including the steps of fabricating a first LED chip array and fabricating a second LED chip array; and the method further includes:

[0012] A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip.

[0013] A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit.

[0014] A second insulating layer is formed on the surface of the drive array away from the first insulating layer, and a plurality of second windows are provided on the second insulating layer to expose at least one electrode of the plurality of second drive units;

[0015] The side surface of the second LED chip array having electrodes is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

[0016] This invention also provides a method for fabricating a single-chip integrated large-area multi-color high-resolution Micro-LED chip, including the steps of fabricating a first LED chip array and fabricating a second LED chip array; and the method further includes:

[0017] A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip.

[0018] A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit.

[0019] A second insulating layer is formed on the side surface of the second LED chip array having electrodes, and a plurality of second windows are provided on the second insulating layer to expose the two electrodes of each second LED chip;

[0020] One surface of the driving array away from the first insulating layer is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

[0021] Compared with existing technologies, the Micro-LED chip for monolithic integrated large-area multi-color high-resolution display provided by this invention reduces the spacing between LED chips and improves the resolution of the display screen by alternating upright and flip-chip arrangements, resulting in a more delicate display effect. Furthermore, this Micro-LED chip for monolithic integrated large-area multi-color high-resolution display uses original substrates for different light-emitting materials and introduces quantum dots to achieve wavelength conversion, avoiding stress problems caused by substrate mismatch, improving product reliability, and providing a solution to reduce the technical difficulty of mass transfer during the manufacturing of LED display modules. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of a Micro-LED device for monolithic integrated large-area multi-color high-resolution display provided in one embodiment of the present invention;

[0023] Figure 2 It is along Figure 1 A top view of the cross-sectional structure formed by the dashed lines in the diagram;

[0024] Figure 3 It is along Figure 1 A bottom view of the cross-sectional structure formed by the dashed lines in the image;

[0025] Figure 4 This is a cross-sectional view of a Micro-LED device for monolithic integrated large-area multi-color high-resolution display provided in one embodiment of the present invention;

[0026] Figure 5 It is along Figure 4 A top view of the cross-sectional structure formed by the dashed lines in the diagram;

[0027] Figure 6 It is along Figure 4 A bottom view of the cross-sectional structure formed by the dashed lines in the image;

[0028] Figure 7 This is a cross-sectional view of a Micro-LED device for monolithic integrated large-area multi-color high-resolution display provided in one embodiment of the present invention;

[0029] Figure 8 It is along Figure 7 A top view of the cross-sectional structure formed by the dashed lines in the diagram;

[0030] Figure 9 It is along Figure 7 The bottom view of the cross-sectional structure formed by the dashed lines in the figure. Detailed Implementation

[0031] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0032] The current challenge facing micro-LEDs is the mass transfer of three-color LEDs. This invention adopts a scheme of alternating upright and flip-chip arrangements, which can effectively reduce problems such as misalignment and low yield that may occur during transfer. In addition, the small size of individual microLEDs may cause accuracy problems when using flip-chip configurations, but the wavelength conversion function of quantum dots can be used to adjust the emission wavelength.

[0033] In existing display module solutions that include stacked thin-film transistor arrays and LED arrays, a common approach to achieve tri-color display is to stack blue and green LEDs sequentially. The light generated by the first LED stack passes through the second and third LED stacks and is emitted to the outside. However, the light-emitting materials of blue and green light exhibit light absorption in non-light-emitting wavelengths; for example, green LEDs will absorb blue light. In this invention, by alternating between upright and flip-chip arrangements and cooperating with a thin-film transistor array, along with a wavelength conversion method, light absorption can be reduced, thereby achieving tri-color display.

[0034] Existing stacking solutions may suffer from stress mismatch due to material differences. This invention, by alternating between upright and flip-chip arrangements, improves product reliability in this regard. Furthermore, while control circuits in multilayer LED devices typically use a layer of LEDs and a layer of control circuitry, this invention utilizes thin-film transistors (TFTs) placed between two stacked LED arrays to simultaneously control the light emission of both arrays, reducing manufacturing costs. Compared to other multilayered LEDs, the alternating upright and flip-chip arrangement of LEDs in this invention, viewed from the side, prevents the active layers of different light-emitting regions from being misaligned, as the active layers in this invention are closer together. Additionally, while some existing technologies employ vias, the flip-chip process used in this invention is simpler and saves on manufacturing costs.

[0035] This invention provides a single-chip integrated large-area multi-color high-resolution Micro-LED chip, comprising:

[0036] A first LED chip array and a second LED chip array are stacked together. The first LED chip array includes a plurality of first LED chips with upright structure, and the second LED chip array includes a plurality of second LED chips with flip-chip structure.

[0037] A driving array is disposed between the first LED chip array and the second LED chip array. The driving array includes multiple driving units, which are integrated in the pixel position of the Micro-LED chip. Each first LED chip and each second LED chip are electrically connected to a corresponding driving unit.

[0038] In one specific embodiment, the driving array includes a thin-film transistor array, and each driving unit includes at least one thin-film transistor.

[0039] In one specific embodiment, the Micro-LED chip further includes:

[0040] A first insulating layer is disposed between the thin-film transistor array and the surface of the first LED chip array having electrodes.

[0041] The second insulating layer is disposed between the thin-film transistor array and the side surface of the second LED chip array having electrodes;

[0042] The thin-film transistor array includes:

[0043] Multiple first thin-film transistors that cooperate with the first LED chip array

[0044] Multiple second thin-film transistors that cooperate with the second LED chip array;

[0045] The first insulating layer has a plurality of first windows, and one electrode of each first LED chip is electrically connected to one electrode of a corresponding first thin film transistor through one first window;

[0046] The second insulating layer has multiple second windows, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second thin film transistor through a second window.

[0047] In one specific embodiment, the material of the thin-film transistor can be MoS2, carbon nanotubes, IGZO or other thin-film transistor materials, and the substrate for growing the first LED chip array and the second LED chip array can be sapphire, silicon carbide or other III-V compound substrates, etc.

[0048] In one specific embodiment, the other electrode of each first LED chip is electrically connected to the other electrode of a corresponding second LED chip.

[0049] In one specific embodiment, both electrodes of each first LED chip are exposed from the corresponding first window.

[0050] In one specific embodiment, both electrodes of each second LED chip are exposed from the corresponding second window.

[0051] In one specific embodiment, the first insulating layer covers one side surface of the first LED chip array where electrodes are distributed or the first surface of the thin film transistor array, and the second insulating layer covers one side surface of the second LED chip array where electrodes are distributed or the second surface of the thin film transistor array, with the second surface being disposed opposite to the first surface.

[0052] In one specific embodiment, the P electrode of each first LED chip passes through a corresponding first window and is electrically connected to the drain of the corresponding first thin-film transistor; and

[0053] The P electrode of each second LED chip passes through the corresponding second window and is electrically connected to the drain of the corresponding second thin-film transistor, or the drain of each second thin-film transistor passes through the corresponding second window and is electrically connected to the P electrode of the corresponding second LED chip.

[0054] In one specific embodiment, the gate electrodes of multiple thin-film transistors located in the same row of the thin-film transistor array are also connected to a corresponding gate electrode control line, and the source electrodes of multiple thin-film transistors located in the same column are also connected to a corresponding source electrode control line.

[0055] In one specific embodiment, the first LED chip and the second LED chip have the same light emission direction.

[0056] In one specific embodiment, the first LED chip array further includes a first wavelength conversion layer covering the light-emitting surface of the first LED chip, and the second LED chip array further includes a second wavelength conversion layer covering the light-emitting surface of the second LED chip.

[0057] In one specific embodiment, both the first wavelength conversion layer and the second wavelength conversion layer can be quantum dot material layers. For example, the quantum dot material layer can convert blue light into red light.

[0058] In a specific embodiment, the first LED chip and the second LED chip can be LED chips with different material systems. The material system of the first LED chip and the second LED chip can be one of GaN, InGaN, GaP, GaAsP, GaAs, GaAsInP, and GaAlAs. For example, the first LED chip can be a GaN-based blue LED chip and the second LED chip can be an InGaN-based green LED chip. The quantum dot material layer can be a CdSe / CdTe quantum dot thin film, etc.

[0059] This invention also provides a method for fabricating a single-chip integrated large-area multi-color high-resolution Micro-LED chip, including the steps of fabricating a first LED chip array and fabricating a second LED chip array; and the method further includes:

[0060] A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip.

[0061] A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit.

[0062] A second insulating layer is formed on the surface of the drive array away from the first insulating layer, and a plurality of second windows are provided on the second insulating layer to expose at least one electrode of the plurality of second drive units;

[0063] The side surface of the second LED chip array having electrodes is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

[0064] This invention also provides a method for fabricating a single-chip integrated large-area multi-color high-resolution Micro-LED chip, including the steps of fabricating a first LED chip array and fabricating a second LED chip array; and the method further includes:

[0065] A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip.

[0066] A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit.

[0067] A second insulating layer is formed on the side surface of the second LED chip array having electrodes, and a plurality of second windows are provided on the second insulating layer to expose the two electrodes of each second LED chip;

[0068] One surface of the driving array away from the first insulating layer is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

[0069] The following will further explain the technical solution, its implementation process and principle in conjunction with the accompanying drawings and specific implementation examples. Unless otherwise specified, the semiconductor fabrication processes and equipment used in the embodiments of the present invention are known to those skilled in the art. The specific process parameters involved are not specifically limited. The terms "first" and "second" are only used to distinguish some structures and are not used to limit the structure of the device.

[0070] Example 1

[0071] Please also refer to Figure 1 , Figure 2 and Figure 3 ,in, Figure 1 This is a schematic diagram of the structure of a Micro-LED device provided in a typical embodiment of the present invention. Figure 2 It is along Figure 1 The top view of the cross-sectional structure at the position indicated by the dashed line. Figure 3 It is along Figure 1The image shows a bottom view of the cross-sectional structure at the position indicated by the dashed line. A Micro-LED device includes a first substrate 1, a first LED chip array 2 disposed on the first substrate, a second substrate 3, a second LED chip array 4 disposed on the second substrate 3, and a thin-film transistor array 5 (i.e., the aforementioned driving array, hereinafter the same) disposed between the first LED chip array 2 and the second LED chip array 4. The thin-film transistor array includes a first portion of thin-film transistors (i.e., the aforementioned first thin-film transistors, hereinafter the same) and a second portion of thin-film transistors (i.e., the aforementioned second thin-film transistors, hereinafter the same). The first portion of thin-film transistors is connected to the first LED chip array 2 and used to control the LEDs of the first LED chip array, and the second portion of thin-film transistors is connected to the second LED chip array 4 and used to control the LEDs of the second LED chip array.

[0072] In this embodiment, the first LED chip array is a conventionally mounted LED chip with light emission direction from the side with electrodes, and the second LED chip array is a flip-chip LED chip with light emission direction from the epitaxial substrate side (i.e., the side opposite to the electrodes).

[0073] In this embodiment, the first LED chip array 2 includes a plurality of first LED chips, a first P electrode 22 covering the first surface of the first LED chips, a first insulating layer 23, a first N electrode 24, and a first metal pad 25 disposed on the surface of the first N electrode 24 and the first insulating layer 23, wherein the first metal pad 25 is electrically connected to the first N electrode 24.

[0074] In this embodiment, the second chip array 4 includes a plurality of second LED chips, a second P electrode 42 covering the second surface of the second LED chips, a second insulating layer 43, a second N electrode 44, and a second metal pad 45 disposed on the surface of the second N electrode 44 and the second insulating layer 43.

[0075] In this embodiment, the thin-film transistor array includes a first portion of thin-film transistors, a second portion of thin-film transistors, and gate control lines 53 and source control lines 54. The first portion of thin-film transistors includes a first gate electrode 511, a first source electrode 512, a first drain electrode 513, a first gate insulating layer 514, a first active region 515, and a connecting metal 516 connecting the first drain electrode 513 and the first P electrode 22. The second portion of thin-film transistors includes a second gate electrode 521, a second source electrode 522, a second drain electrode 523, a second gate insulating layer 524, and a second active region 525. The first portion of thin-film transistors and the second portion of thin-film transistors are arranged at intervals.

[0076] In this embodiment, the first metal pad 25 on the first insulating layer 23 of the first LED chip array and the second metal pad 45 on the second insulating layer 43 of the second LED chip array are connected by a first bump solder ball 46; the first P electrode 22 of the first LED chip array and the first drain electrode 513 in the first part of the thin film transistor are connected one-to-one by a connecting metal 516; the second P electrode 42 of the second LED chip array and the second drain electrode 523 in the second part of the thin film transistor are connected by a second bump solder ball.

[0077] In this embodiment, the gate electrodes in the thin-film transistor array are controlled by gate control lines 53. Each row of gate control lines 53 is connected to all gate electrodes in that row of the thin-film transistor array, and the gate control lines 53 are connected to an external control power supply via external pads 531 at their ends. All source electrodes in the thin-film transistor array are controlled by source control lines 54. Each column of source control lines 54 is connected to all source electrodes in that column of the thin-film transistor array, and the source control lines are connected to an external control power supply via external pads 541 at their ends. The external pads 251 are disposed on the first metal pads 213 on the first insulating layer 23, and the LED device is connected to an external driving power supply via the external pads 251.

[0078] In this embodiment, the first LED chip array is a blue LED chip, and the second LED chip array is a red LED chip.

[0079] In this embodiment, both the first P electrode and the second P electrode can be transparent electrodes. The connecting metal, the first bump solder ball, the second bump solder ball, the first metal solder pad, the second metal solder pad, the external solder pad, the active region, the source electrode, the drain electrode, and the gate electrode can all be known to those skilled in the art. Their specific structures, materials, and dimensions can be adjusted according to specific circumstances, and no specific limitations are made here.

[0080] The following details the fabrication method of the Micro-LED device according to Embodiment 1 of the present invention, specifically including the following steps:

[0081] (1) A first LED chip array is fabricated on a sapphire substrate, and a first insulating layer 23, a first metal pad 25, an external pad 251 and a thin film transistor array are formed on the first LED chip array;

[0082] Step S1: The epitaxial structure layer is processed into the first LED chip array through photolithography, etching and other processes;

[0083] Step S2: A first P electrode 22 and a first N electrode 24 are fabricated on the P-electrode surface of the first LED chip array (i.e., the aforementioned first surface, the same below) using sputtering combined with photolithography and etching processes; the material of the first P electrode 22 can be indium tin oxide (ITO) or the like, and the material of the first N electrode 24 can be a combination of metals such as titanium, aluminum, nickel, and gold or others;

[0084] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a first insulating layer 23 is formed by growing a high-temperature silicon dioxide layer under high-temperature conditions. Then, the first insulating layer 23 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the first P electrode 22 and the first N electrode 24.

[0085] Step S4: Back gate electrodes 511 and 521 (i.e., the aforementioned first gate electrode 511 and second gate electrode 521) and gate control line 53 are grown on the first insulating layer 23 by sputtering and photolithography etching. A gate insulating layer 514 and 524 (i.e., the aforementioned first gate insulating layer 514 and second gate insulating layer 524, the same below) are grown on the back gate electrode. Molybdenum disulfide is transferred as an active region to the corresponding position corresponding to the back gate electrode (i.e., the aforementioned gate electrode or the first and second gate electrodes, the same below) 511 and 521 by a transfer method. Finally, source and drain electrodes that cooperate with the active region are grown by sputtering and photolithography etching. The first P electrode of the first LED chip array is connected to the drain electrode of the first part of the thin film transistor by connecting metal 516. The source electrodes of the thin film transistor array located in the same column are connected by source control line 54, and the gate control line 53 is connected through the gate electrodes of the thin film transistor array located in the same row.

[0086] Step S5: Using sputtering combined with photolithography and lift-off processes, a first metal pad 213 is formed on the first N electrode 24 and part of the first insulating layer 23. The material of the first metal pad 213 can be aluminum or other metals.

[0087] Step S6: Using electron beam evaporation combined with photolithography and lift-off processes, an external bonding pad 251 is simultaneously fabricated on the first metal bonding pad 25, and external bonding pads 531 and 541 are fabricated at the ends of the gate control line and the source control line.

[0088] (2) A second LED chip array is fabricated on a sapphire substrate, and a second insulating layer 43, a second metal pad 45, and a bump solder ball are formed on the P-electrode surface (i.e., the aforementioned second surface) of the second LED chip array:

[0089] Step S1: The epitaxial structure layer is processed into a second LED chip array through photolithography, etching and other processes;

[0090] Step S2: A second P electrode 42 and a second N electrode 44 are prepared on the P-electrode surface of the second LED chip array using sputtering combined with photolithography and etching processes. The material of the second P electrode 42 can be indium tin oxide (ITO) or the same, and the material of the second N electrode 44 can be titanium, aluminum, nickel, gold, or others.

[0091] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a high-temperature silicon dioxide layer grown under high-temperature conditions is used to form a second insulating layer 43. Then, the second insulating layer 43 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the second P electrode 42 and the second N electrode 44.

[0092] Step S4: Using sputtering combined with photolithography and lift-off processes, a second metal pad 45 is formed on the second N electrode 44 and part of the second insulating layer 43. The material of the second metal pad 45 can be aluminum or other metals.

[0093] Step S5: Apply protruding solder balls to the upper surface of the second metal pad 45 and the second P electrode 42 using photolithography and electroplating processes.

[0094] (3) The second LED chip array is flip-chip connected to the first LED chip array, so that the first metal pad 25 and the second metal pad 45, the drain electrode of the second part of the thin film transistor array and the bumped solder ball are connected, and the flip-chip connection can be achieved by bonding by pressure heating and then ultrasonic bonding.

[0095] Example 2:

[0096] The structure of the Micro-LED device in this embodiment is basically the same as that in Embodiment 1. The first LED chip array in this embodiment is a blue LED chip, and the second LED chip array is a green LED chip. The difference between this embodiment and Embodiment 1 is that a quantum dot material layer 26 is deposited on the P electrode of some blue LEDs. The quantum dot material layer 26 can realize wavelength conversion, so that the region emits red light, thereby obtaining an LED device that emits three colors of light (red, green, and blue).

[0097] A method for fabricating a Micro-LED device specifically includes the following steps:

[0098] (1) A first LED chip array is fabricated on a sapphire substrate 1, and a first insulating layer 23, a first metal pad 25, an external pad 251 and a thin film transistor array are formed on the first LED chip array.

[0099] Step S1: The epitaxial structure layer is processed into the first LED chip array through photolithography, etching and other processes;

[0100] Step S2: A first P electrode 22 and a first N electrode 24 are prepared on the P-electrode surface of the first LED chip array (i.e., the aforementioned first surface, the same below). A CdSe / CdTe quantum dot material layer 26 for color conversion is deposited on the first P electrode 22 of the first LED chip array. The CdSe / CdTe quantum dot material layer 26 can realize emission wavelength conversion. The CdSe / CdTe quantum dot material layer 26 covers a portion of the first P electrode 22.

[0101] The first P electrode 22 and the first N electrode 24 can be prepared by sputtering combined with photolithography and etching processes, etc. The material of the first P electrode 22 can be indium tin oxide (ITO), etc., and the material of the first N electrode 24 can be a combination of metals such as titanium, aluminum, nickel, and gold, or others.

[0102] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a first insulating layer 23 is formed by growing a high-temperature silicon dioxide layer under high-temperature conditions. Then, the first insulating layer 23 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the first P electrode 22, the first N electrode 24, and the CdSe / CdTe quantum dot material layer 26.

[0103] Step S4: Back gate electrodes 511, 521 and gate control lines 53 are grown on the first insulating layer 23 by sputtering combined with photolithography and etching. A gate insulating layer 514, 524 is grown on the back gate electrodes. Molybdenum disulfide is transferred as an active region to the position corresponding to the back gate electrodes 511, 521 by a transfer method. Finally, source and drain electrodes that cooperate with the active regions are grown by sputtering and photolithography. The first P electrode of the first LED chip array is connected to the drain electrode of the first part of the thin film transistor by connecting metal 516. The source electrodes of the thin film transistor array located in the same column are connected by source control lines 54, and the gate control lines 53 are connected through the gate electrodes of the thin film transistor array located in the same row.

[0104] Step S5: Using sputtering combined with photolithography and lift-off processes, a first metal pad 213 is formed on the first N electrode 24 and part of the first insulating layer 23. The material of the first metal pad 213 is aluminum or other metal.

[0105] Step S6: Using electron beam evaporation combined with photolithography and lift-off processes, an external bonding pad 251 is simultaneously fabricated on the first metal bonding pad 25, and external bonding pads 531 and 541 are fabricated at the ends of the gate control line and the source control line.

[0106] (2) A second LED chip array is fabricated on a sapphire substrate, and a second insulating layer 43, a second metal pad 45, and a bump solder ball are formed on the P-electrode surface (i.e., the aforementioned second surface) of the second LED chip array:

[0107] Step S1: The epitaxial structure layer is processed into a second LED chip array through photolithography, etching and other processes;

[0108] Step S2: A second P electrode 42 and a second N electrode 44 are prepared on the P-electrode surface of the second LED chip array using sputtering combined with photolithography and etching processes. The material of the second P electrode 42 can be indium tin oxide (ITO) or the same, and the material of the second N electrode 44 can be titanium, aluminum, nickel, gold, or others.

[0109] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a high-temperature silicon dioxide layer grown under high-temperature conditions is used to form a second insulating layer 43. Then, the second insulating layer 43 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the second P electrode 42 and the second N electrode 44.

[0110] Step S4: Using sputtering combined with photolithography and lift-off processes, a second metal pad 45 is formed on the second N electrode 44 and part of the second insulating layer 43. The material of the second metal pad 45 can be aluminum or other metals.

[0111] Step S5: Apply protruding solder balls to the upper surface of the second metal pad 45 and the second P electrode 42 using photolithography and electroplating processes.

[0112] (3) The second LED chip array is flip-chip connected to the first LED chip array, so that the first metal pad 25 and the second metal pad 45, the drain electrode of the second part of the thin film transistor array and the bumped solder ball are connected, and the flip-chip connection can be achieved by bonding by pressure heating and then ultrasonic bonding.

[0113] Example 3:

[0114] Please see Figures 7-9 The structure of the Micro-LED device in this embodiment is basically the same as that in Embodiment 1. The first LED chip array is a blue LED chip and the second LED chip array is a green LED chip. In this embodiment, a quantum dot material layer 26 is also provided on the surface of the second LED chip array facing the first LED chip array. The quantum dot material layer 26 can realize wavelength conversion, thereby enabling the LED device to emit tricolor light.

[0115] A method for fabricating a Micro-LED device specifically includes the following steps:

[0116] (1) A first LED chip array is fabricated on a sapphire substrate, and a first insulating layer, a first metal pad 25, an external pad 251 and a thin film transistor array are formed on the first LED chip array;

[0117] Step S1: The epitaxial structure layer is processed into the first LED chip array through photolithography, etching and other processes;

[0118] Step S2: A first P electrode 22 and a first N electrode 24 are fabricated on the P-electrode surface of the first LED chip array (i.e., the aforementioned first surface, the same below) using sputtering combined with photolithography and etching processes; the material of the first P electrode 22 can be indium tin oxide (ITO) or the like, and the material of the first N electrode 24 can be a combination of metals such as titanium, aluminum, nickel, and gold or others;

[0119] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a first insulating layer 23 is formed by growing a high-temperature silicon dioxide layer under high-temperature conditions. Then, the first insulating layer 23 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the first P electrode 22 and the first N electrode 24.

[0120] Step S4: Back gate electrodes 511 and 521 (i.e., the aforementioned first gate electrode 511 and second gate electrode 521) and gate control line 53 are grown on the first insulating layer 23 by sputtering combined with photolithography and etching processes. A gate insulating layer 514 and 524 (i.e., the aforementioned first gate insulating layer 514 and second gate insulating layer 524) are grown on the back gate electrodes. Molybdenum disulfide is transferred as an active region to the corresponding position corresponding to the back gate electrodes 511 and 521 by a transfer method. Finally, source and drain electrodes that cooperate with the active region are grown by sputtering and photolithography. The first P electrode of the first LED chip array is connected to the drain electrode of the first part of the thin film transistor by metal. The source electrodes of the thin film transistor array located in the same column are connected by the source control line 54, and the gate control line 53 is connected through the gate electrodes of the thin film transistor array located in the same row.

[0121] Step S5: Using sputtering combined with photolithography and lift-off processes, a first metal pad 213 is formed on the first N electrode 24 and part of the first insulating layer 23. The material of the first metal pad 213 can be aluminum or other metals.

[0122] Step S6: Using electron beam evaporation combined with photolithography and lift-off processes, an external bonding pad 251 is simultaneously fabricated on the first metal bonding pad 25, and external bonding pads 531 and 541 are fabricated at the ends of the gate control line and the source control line.

[0123] (2) A second LED chip array is fabricated on a sapphire substrate, and a second insulating layer 43, a second metal pad 45, a bump solder ball, and a quantum dot material layer 26 are formed on the P-polar surface (i.e., the aforementioned second surface) formed on the second LED chip array:

[0124] Step S1: The epitaxial structure layer is processed into a second LED chip array through photolithography, etching and other processes;

[0125] Step S2: A second P electrode 42 and a second N electrode 44 are prepared on the P-electrode surface of the second LED chip array using sputtering combined with photolithography and etching processes. The material of the second P electrode 42 can be indium tin oxide (ITO) or the same, and the material of the second N electrode 44 can be titanium, aluminum, nickel, gold, or others.

[0126] Step S3: Using equipment such as a chemical vapor deposition tube furnace, a second insulating layer 43 is formed by growing a high-temperature silicon dioxide layer under high-temperature conditions. Then, the second insulating layer 43 is fabricated into a preset pattern by photolithography and etching processes to expose at least a portion of the second P electrode 42 and the second N electrode 44. A color conversion CdSe / CdTe quantum dot material layer 26 is deposited at selected locations on the second insulating layer 43, so that some LEDs in the flip-chip first LED chip array can achieve emission wavelength conversion.

[0127] Step S4: Using sputtering combined with photolithography and lift-off processes, a second metal pad 45 is formed on the second N electrode 44 and part of the second insulating layer 43. The material of the second metal pad 45 can be aluminum or other metals.

[0128] Step S5: Apply protruding solder balls to the upper surface of the second metal pad 45 and the second P electrode 42 using photolithography and electroplating processes.

[0129] (3) The second LED chip array is flip-chip connected to the first LED chip array, so that the first metal pad 25 and the second metal pad 45, the drain electrode of the second part of the thin film transistor array and the bumped solder ball are connected, and the flip-chip connection can be achieved by bonding by pressure heating and then ultrasonic bonding.

[0130] It should be noted that the above embodiments are merely exemplary and are mainly used to explain and illustrate the structure and fabrication process of a Micro-LED device in the embodiments of the present invention. It should be understood that the first insulating layer, the second insulating layer, and the thin-film transistor in the present invention can of course be fabricated in other ways known to those skilled in the art, which will not be described in detail here.

[0131] This invention provides a monolithically integrated large-area multi-color high-resolution Micro-LED chip. By alternating between upright and flip-chip arrangements, the spacing between LED chips is reduced, increasing the resolution of the display screen and resulting in a more delicate display effect. Furthermore, this invention utilizes original substrates for different luminescent materials and introduces quantum dots to achieve wavelength conversion, avoiding stress problems caused by substrate mismatch and improving product reliability. It also provides a solution to reduce the technical difficulty of mass transfer during the manufacturing of LED display modules.

[0132] This invention is not limited to the above-described embodiments. If any modifications or variations to this invention do not depart from the spirit and scope of this invention, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this invention, then this invention also intends to include such modifications and variations.

Claims

1. A Micro-LED chip for monolithic integrated large-area multi-color high-resolution display, characterized in that, include: A first LED chip array and a second LED chip array are stacked together. The first LED chip array includes a plurality of first LED chips with upright structure, and the second LED chip array includes a plurality of second LED chips with flip-chip structure. A driving array is disposed between the first LED chip array and the second LED chip array. The driving array includes multiple driving units, which are integrated in the pixel position of the Micro-LED chip. Each first LED chip and each second LED chip are electrically connected to a corresponding driving unit. The driving array includes a thin-film transistor array, and each driving unit includes at least one thin-film transistor. A first insulating layer is disposed between the thin-film transistor array and the surface of the first LED chip array having electrodes. The second insulating layer is disposed between the thin-film transistor array and the side surface of the second LED chip array having electrodes; The thin-film transistor array includes: Multiple first thin-film transistors that cooperate with the first LED chip array Multiple second thin-film transistors that cooperate with the second LED chip array; The first insulating layer has a plurality of first windows, and one electrode of each first LED chip is electrically connected to one electrode of a corresponding first thin film transistor through one first window; The second insulating layer has multiple second windows, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second thin film transistor through a second window.

2. The Micro-LED chip according to claim 1, characterized in that: The other electrode of each first LED chip is electrically connected to the other electrode of a corresponding second LED chip; and / or, both electrodes of each first LED chip are exposed from the corresponding first window; and / or, both electrodes of each second LED chip are exposed from the corresponding second window.

3. The Micro-LED chip according to claim 1, characterized in that: The first insulating layer covers one side surface of the first LED chip array where electrodes are distributed or the first surface of the thin film transistor array, and the second insulating layer covers one side surface of the second LED chip array where electrodes are distributed or the second surface of the thin film transistor array, with the second surface being disposed opposite to the first surface.

4. The Micro-LED chip according to claim 1, characterized in that: The P electrode of each first LED chip passes through a corresponding first window and is electrically connected to the drain of the corresponding first thin-film transistor; as well as The P electrode of each second LED chip passes through the corresponding second window and is electrically connected to the drain of the corresponding second thin-film transistor, or the drain of each second thin-film transistor passes through the corresponding second window and is electrically connected to the P electrode of the corresponding second LED chip.

5. The Micro-LED chip according to claim 1, characterized in that: The gate electrodes of multiple thin-film transistors located in the same row of the thin-film transistor array are also connected to a corresponding gate electrode control line, and the source electrodes of multiple thin-film transistors located in the same column are also connected to a corresponding source electrode control line.

6. The Micro-LED chip according to claim 1, characterized in that: The first LED chip and the second LED chip have the same light emission direction.

7. The Micro-LED chip according to claim 1, characterized in that: The first LED chip array further includes a first wavelength conversion layer covering the light-emitting surface of the first LED chip, and the second LED chip array further includes a second wavelength conversion layer covering the light-emitting surface of the second LED chip.

8. A method for fabricating a monolithically integrated large-area multi-color high-resolution Micro-LED chip as described in any one of claims 1-7, comprising the steps of fabricating a first LED chip array and fabricating a second LED chip array; characterized in that, The manufacturing method further includes: A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip. A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit. A second insulating layer is formed on the surface of the drive array away from the first insulating layer, and a plurality of second windows are provided on the second insulating layer to expose at least one electrode of the plurality of second drive units; The side surface of the second LED chip array having electrodes is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

9. A method for fabricating a monolithically integrated large-area multi-color high-resolution Micro-LED chip as described in any one of claims 1-7, comprising the steps of fabricating a first LED chip array and fabricating a second LED chip array; characterized in that, The manufacturing method further includes: A first insulating layer is formed on one side surface of the first LED chip array having electrodes, and a plurality of first windows are provided on the first insulating layer to expose two electrodes of each first LED chip. A driving array is disposed on a first insulating layer. The driving array includes a plurality of first driving units and a plurality of second driving units, and an electrode of each first LED chip is electrically connected to an electrode of a corresponding first driving unit. A second insulating layer is formed on the side surface of the second LED chip array having electrodes, and a plurality of second windows are provided on the second insulating layer to expose the two electrodes of each second LED chip; One surface of the driving array away from the first insulating layer is attached to the second insulating layer, and one electrode of each second LED chip is electrically connected to one electrode of a corresponding second driving unit.

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