Pixel unit and manufacturing method thereof, microdisplay, pixel-level individual element

Abstract

This application discloses a pixel unit, a manufacturing method thereof, a microdisplay, and a pixel-level individual element. The pixel unit includes a backplate and a display unit disposed on the backplate, the display unit including a first element layer and a second element layer stacked vertically in a direction away from the backplate, the first element layer including a first compound light-emitting layer and a second compound light-emitting layer adjacent to the first element layer, the second element layer including a color conversion layer and a third compound light-emitting layer adjacent to the first element layer, the color conversion layer being disposed above the first compound light-emitting layer. In this application, the color conversion layer allows compounds with significantly reduced external quantum efficiency to emit color through color conversion, thereby reducing power consumption and improving performance. Furthermore, the pixel unit occupies a smaller horizontal space, which reduces pixel density limitations compared to horizontally arranged pixel units, thereby effectively reducing the reduction in external quantum efficiency caused by size effects, reducing power consumption, improving performance such as brightness, and effectively improving yield.

Description

[Technical Field]

[0001] The present application relates to the technical field of semiconductor devices, in particular to pixel units and manufacturing methods thereof, microdisplays, and pixel-level discrete elements. [Background technology]

[0002] Micro-LED display technology is widely regarded as the next generation of display technology, and holds great potential in both wearable devices and direct display. Conventional LED red light sources are based on the AlGaInP material system, while green and blue light sources are both based on the InGaN material system. The development of these two material systems has brought about significant advances in applications such as LED lighting and display backlighting. However, when conventional LEDs are directly used as display pixels, the external quantum efficiency decreases due to size effects when the size drops from the millimeter level to the micrometer level, especially below 20 micrometers, resulting in problems with the power consumption and performance of micro-LEDs. The red light performance of AlGaInP-based LEDs is particularly severe.

[0003] More importantly, the yield loss caused by the above defects cannot be ignored, and due to the miniaturization of devices and the scenario of display applications, the industry has very high requirements for the yield of Micro-LED. At the 15μm / 5μm level, the external quantum efficiency (EQE) of Micro-LED (ULED) is found to be much lower than that of conventional size LEDs (45%) and OLEDs (22%), and the lack of brightness and energy loss caused by this efficiency decrease will greatly restrict the development of microdisplays.

[0004] Similarly, when the size of pixel-level individual elements enters the μm level, especially below 20 μm, the reduction in external quantum efficiency caused by size effects poses problems in power consumption and performance of pixel-level individual elements, and this is particularly serious for the red light performance of AlGaInP-based elements.

[0005] Therefore, there is a need to find a semiconductor device that can effectively overcome the above drawbacks. Summary of the Invention

[0006] The object of the present application is to provide a pixel unit and a manufacturing method thereof, a microdisplay, and a pixel-level individual element that can effectively reduce the influence of size effect and effectively deal with yield loss.

[0007] In order to achieve the object of the present application, according to a first aspect of the present application, there is proposed a pixel unit for use in a semiconductor device, the pixel unit including: a back plate; and a display unit provided on the back plate, the display unit including a first element layer and a second element layer stacked vertically in sequence along a direction away from the back plate, the first element layer including a first compound light-emitting layer and a second compound light-emitting layer provided adjacent to each other, the second element layer including a color conversion layer and a third compound light-emitting layer provided adjacent to each other, the color conversion layer being provided above the first compound light-emitting layer.

[0008] In a preferred embodiment, the display device further includes a common cathode arranged in a circumferential direction of the display unit, the common cathode being connected to the first compound light-emitting layer, the second compound light-emitting layer, and the third compound light-emitting layer, respectively, and being connected to an external cathode.

[0009] In a preferred embodiment, the device further includes an enhanced common cathode connected to the common cathode and surrounding a first region and a second region that are isolated from each other together with the common cathode, wherein the first compound light-emitting layer and the color conversion layer are stacked in the first region, and the second compound light-emitting layer and the third compound light-emitting layer are stacked in the second region.

[0010] In a preferred embodiment, the first element layer further includes a first bonding layer made of an insulating material; The first bonding layer is provided on the back plate, and the first compound light-emitting layer and the second compound light-emitting layer are each provided on one side of the first bonding layer spaced apart from the back plate.

[0011] In a preferred embodiment, the first element layer further includes a first anode electrical connection structure and a second anode electrical connection structure, wherein the first anode electrical connection structure has one end connected to the first compound light-emitting layer and the other end extending toward the back plate, and the second anode electrical connection structure has one end connected to the second compound light-emitting layer and the other end extending toward the back plate.

[0012] In a preferred embodiment, the first compound light-emitting layer includes a first P-type ohmic contact layer, a first compound semiconductor layer, and a first N-type ohmic contact layer, which are provided in this order; the first P-type ohmic contact layer is provided in close contact with the first junction layer and has an area larger than that of the first compound semiconductor layer; and the first anode electrical connection structure is provided on a side of the first compound semiconductor layer, with a portion thereof sequentially penetrating the first P-type ohmic contact layer and the first junction layer.

[0013] In a preferred embodiment, the common cathode includes a first cathode electrical connection structure connected to the first N-type ohmic contact layer.

[0014] In a preferred embodiment, the second element layer further includes a second bonding layer made of a transparent insulating material, the second bonding layer being provided on the first element layer, and the color conversion layer and the third compound light-emitting layer being each provided on one side of the second bonding layer spaced apart from the first element layer.

[0015] In a preferred embodiment, the color conversion layer is provided on the second bonding layer, and its projected area on the back plate is larger than the projected area of the first compound light-emitting layer on the back plate.

[0016] In a preferred embodiment, the color conversion layer uses a photochromic material, and the wavelength of the light source for the first compound semiconductor layer is shorter than the wavelength of the light for the color conversion layer.

[0017] In a preferred embodiment, the color conversion layer uses at least one of a red light quantum dot material or a red phosphor material.

[0018] In a preferred embodiment, the second element layer further includes a third anode electrical connection structure provided on a side of the third compound semiconductor layer, and the third anode electrical connection structure has one end connected to the third compound light-emitting layer and the other end extending toward the backplate.

[0019] In a preferred embodiment, the display unit further includes a first insulating coating layer and a second insulating coating layer, both of which are made of a transparent insulating material, wherein the first insulating coating layer covers the first compound light-emitting layer, the second compound light-emitting layer, the first anode electrical connection structure, the second anode electrical connection structure, part of the third anode electrical connection structure, and part of the common cathode, and the second insulating coating layer covers the color conversion layer, the third compound light-emitting layer, part of the third anode electrical connection structure, and part of the common cathode.

[0020] In a preferred embodiment, the back plate is provided with a driving circuit, and the driving circuit is provided with at least one anode including a first anode, a second anode, and a third anode, wherein the first anode electrical connection structure is connected to the first anode, the second anode electrical connection structure is connected to the second anode, and the third anode electrical connection structure is connected to the third anode.

[0021] In a preferred embodiment, the display unit further includes a water vapor barrier layer provided on the surface of the second element layer.

[0022] In a preferred embodiment, the device further includes at least four pads including a cathode pad and at least three anode pads, wherein at least a portion of any one of the at least four pads is embedded in the back plate, the common cathode is connected to the cathode pad, and the first anode electrical connection structure, the second anode electrical connection structure, and the third anode electrical connection structure are each connected to a corresponding anode pad among the at least three anode pads.

[0023] In a preferred embodiment, the element body is provided separately from the back plate, at least four of the pads are provided separately from the back plate, and the pixel-level individual element further includes an insulating support structure covering the element body and connected to the back plate.

[0024] In a preferred embodiment, the blocking and supporting structure includes a covering portion and a fixing portion connected to each other, the covering portion covering the element body, and the fixing portion connected to the back plate.

[0025] According to a second aspect, there is provided a manufacturing method for manufacturing the pixel unit according to the first aspect, the manufacturing method including: preparing a back plate; bonding a first target compound semiconductor, which has been prepared in advance, to the back plate so as to form a first bonding layer; constructing a first compound light-emitting layer and a second compound light-emitting layer adjacent to each other to form a first element layer; and then bonding a second target compound semiconductor, which has been prepared in advance to form a second bonding layer, to one side of the first element layer spaced from the back plate; constructing a third compound light-emitting layer and a color conversion layer adjacent to the third compound light-emitting layer and above the first compound light-emitting layer to form a second element layer.

[0026] In a preferred embodiment, bonding a pre-prepared first target compound semiconductor to the backplate includes: coating an insulating material on the entire surface of the backplate where at least one anode is provided, and forming at least one through-hole corresponding to at least one of the anodes; fabricating a first P-type ohmic contact layer on the surface of the first target compound semiconductor, and coating an insulating material on the entire surface of the first P-type ohmic contact layer; bonding the backplate and the first target compound semiconductor; and removing the substrate of the first target compound semiconductor to expose the N-type ohmic contact layer of the first target compound semiconductor.

[0027] In a preferred embodiment, constructing the first compound light-emitting layer and the second compound light-emitting layer adjacent to each other to form the first device layer includes: dividing the first target compound semiconductor, with the N-type ohmic contact layer exposed, into the first compound light-emitting layer and the second compound light-emitting layer adjacent to each other by patterning etching; covering the entire surfaces of the first compound light-emitting layer and the second compound light-emitting layer to form a first insulating coating layer; patterning etching the first insulating coating layer to form a first anode electrical connection channel, a second anode electrical connection channel, a first cathode electrical connection channel, and a second cathode electrical connection channel, respectively; and applying a metal coating to a surface of the first insulating coating layer to form a first anode electrical connection structure, a second anode electrical connection structure, a first cathode electrical connection structure, and a second cathode electrical connection structure, respectively.

[0028] In a preferred embodiment, constructing a third compound light-emitting layer and filling it to form a color conversion layer adjacent to the third compound light-emitting layer includes: forming a second target compound semiconductor in the third compound light-emitting layer by patterning etching, with an N-type ohmic contact layer exposed; covering the entire surface where the third compound light-emitting layer is located to form a second insulating coating layer; patterning etching the second insulating coating layer, the second bonding layer, the first insulating coating layer, and the first bonding layer to form a third anode electrical connection channel, a third cathode electrical connection channel, and a first slot, respectively; filling the first slot with a color conversion material to form a color conversion layer provided on the second bonding layer; and performing metal coating on the surface where the second insulating coating layer is located to form a third anode electrical connection structure connected to the third anode and a third cathode electrical connection structure connected to the cathode, thereby forming the second element layer.

[0029] In a preferred embodiment, after the construction of the second element layer is completed, the method further includes patterning and etching the second element layer and the first element layer to form an enhanced common cathode channel, a portion of which is located between the third compound light-emitting layer and the color conversion layer and a portion of which is located between the first compound light-emitting layer and the second compound light-emitting layer; and metal coating the surface of the second element layer to form the enhanced common cathode, which is connected to the common cathode and surrounds the first and second regions that are isolated from each other together with the common cathode.

[0030] In a preferred embodiment, after the construction of the second element layer is completed, the method further comprises coating a water vapor barrier material on the surface of the second element layer so as to form a water vapor barrier layer.

[0031] According to a third aspect, there is provided a manufacturing method for manufacturing the pixel unit according to the first aspect, the manufacturing method including: preparing a backplate; bonding a first target compound semiconductor that has been prepared in advance to the backplate, and constructing a first compound light-emitting layer and a second compound light-emitting layer that are adjacent to each other to form a first element layer; and then bonding a second target compound semiconductor that has been prepared in advance to one side of the first element layer that is spaced from the backplate, and constructing a third compound light-emitting layer and a color conversion layer that is adjacent to the third compound light-emitting layer and above the first compound light-emitting layer to form a second element layer.

[0032] In a preferred embodiment, preparing a backplate includes etching a previously prepared backplate to form at least four cavities; coating a sacrificial layer on one side of the backplate where the at least four cavities are formed; and constructing at least four pads, including a cathode pad and at least three anode pads, on the one side of the backplate where the sacrificial layer is coated, so that a portion of each pad is embedded in the corresponding cavity.

[0033] In a preferred embodiment, after the construction of the second element layer is completed, the method includes coating a dielectric material on the surface of the element body and extending it to a portion of the surface of the back plate so as to form a blocking support structure; and etching the sacrificial layer on one side of the back plate where the dielectric material is not coated so as to separate at least four of the pads from the back plate, wherein the etching rate ratio between the sacrificial layer and the back plate is greater than 10:1, and the etching rate ratio between the sacrificial layer and the blocking support structure is greater than 10:1.

[0034] According to a fourth aspect, there is provided a microdisplay including: a microdisplay back plate including a driving circuit, an input interface, and an output interface; a display area provided on the microdisplay back plate, the display area including display units included in at least two pixel units according to the first aspect, or display units included in pixel units manufactured by the manufacturing method according to the second aspect, arranged in an array; and a surrounding common cathode electrically connected to the common cathode of each of the display units.

[0035] According to a fifth aspect, there is provided a pixel-level discrete element including: an individual element backplate including at least three anode pads and at least one cathode pad; and an element body provided on the individual element backplate, the element body including at least two display units included in the pixel units described in the first aspect, or display units included in the pixel unit manufactured by the manufacturing method described in the third aspect.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The present application provides a pixel unit, a manufacturing method thereof, a microdisplay, and a pixel-level individual element. The pixel unit includes a backplate and a display unit disposed on the backplate, the pixel unit including a first element layer and a second element layer stacked vertically in a direction away from the backplate, the first element layer including a first compound light-emitting layer and a second compound light-emitting layer adjacent to the first element layer, the second element layer including a color conversion layer and a third compound light-emitting layer adjacent to the first element layer, the color conversion layer being disposed above the first compound light-emitting layer. The color conversion layer allows the compound light-emitting layer, which has a significantly reduced external quantum efficiency, to emit color through color conversion, thereby reducing power consumption and improving performance. The pixel unit also provides a multicolor display by vertically stacking at least two element layers on the backplate. The pixel unit occupies a small horizontal space, minimizing pixel density limitations and effectively reducing the reduction in external quantum efficiency caused by size effects, effectively reducing power consumption, improving performance such as brightness, and effectively improving yield.

[0038] Furthermore, by providing the common cathode of the present application in the circumferential direction of the display unit, the area ratio of the cathode in the display unit can be reduced, the area ratio of the light-emitting region can be increased, and the influence of the size effect can be reduced. At the same time, the number of stacked element layers in the vertical direction can be increased or redundant circuits can be formed, which effectively prevents optical crosstalk between adjacent pixel units and avoids light leakage from the color conversion layer.

[0039] The pixel unit according to the present invention further includes an enhanced common cathode connected to the common cathode and surrounding the first and second regions, the first and second regions being isolated from each other, the first compound light-emitting layer and the color conversion layer being stacked in the first region, and the second and third compound light-emitting layers being stacked in the second region. The enhanced common cathode can effectively enhance electrical reinforcement, prevent optical crosstalk between adjacent compound light-emitting layers, and, more importantly, prevent light overflow from the first compound light-emitting layer.

[0040] Furthermore, since the projected area of the color conversion layer of the present invention on the back plate is larger than the projected area of the first compound light-emitting layer on the back plate, light overflow from the first compound light-emitting layer is prevented.

[0041] Furthermore, the color conversion layer of the present application is made of a red quantum dot material, and the wavelength of the light source of the first compound semiconductor layer is smaller than the wavelength of the red light. This not only achieves red light through color conversion while avoiding the power consumption and performance defects caused by external quantum effects due to the size effect of the AlGaInP red light system, but also effectively solves the environmental protection issues caused by the GaAs red light system, and at the same time, avoids the high activity reliability issues caused by the ultra-large specific surface area of the green and blue quantum dots.

[0042] Furthermore, the pixel unit manufacturing method according to the present application uses a similar damascene process for element manufacturing, cathode electrical connection, and anode electrical connection to passivate and prepare for the next step of bonding. Compared to the conventional method of building an electrical connection structure by etching a metal layer, this method reduces the difficulty of the process of building electrical connections in a stacking method, and improves the feasibility of building an electrical connection structure, especially for metals (such as copper) that are difficult to dry etch.

[0043] It is only necessary for the present application to achieve at least one of the above-mentioned technical effects. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a schematic diagram showing the structure of the pixel unit in a top view angle according to the first embodiment. FIG. [Figure 2] FIG. 2 is a cross-sectional view taken along the line xx in FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view taken along line y1-y1 in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line y2-y2 in FIG. [Figure 5] FIG. 2 is a cross-sectional view taken along line y3-y3 in FIG. [Figure 6] FIG. 2 is a schematic diagram illustrating an exemplary circuit structure of the back plate of Example 1. [Figure 7] 1 is a schematic diagram showing the circuit structure of any one of the element layers in Example 1. FIG. [Figure 8] FIG. 2 is a schematic diagram illustrating an exemplary circuit structure of another back plate of Example 1. [Figure 9] FIG. 10 is a structural diagram in which a top metal is provided on the surface of the back plate in Example 1. [Figure 10] 1 is a structural diagram in which an in-situ reflecting mirror is provided on the surface of the back plate in Example 1. FIG. [Figure 11] 1 is reflectance data in the visible wavelength range for an exemplary in-situ reflector of Example 1. [Figure 12] 1 is a schematic diagram showing the structure of a top view angle of a pixel unit including an enhanced common cathode according to Example 1; FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along the line xx in FIG. 12. [Figure 14] 2 is a cross-sectional view of another pixel unit including an enhanced common cathode of Example 1 taken along the xx cross section. [Figure 15] 2 is a cross-sectional view of another pixel unit of the first embodiment taken along the line xx. [Figure 16] xx cross-sectional view of a pixel unit having an optical reinforcement structure and an enhanced common cathode in Example 1. FIG. [Figure 17] FIG. 1 is a schematic diagram showing an exemplary actual CSP package layout of Example 1. [Figure 18] FIG. 10 is a schematic diagram showing the structure of a microdisplay according to a second embodiment. [Figure 19] 10 is a schematic diagram showing an arrangement of adjacent pixel units in a microdisplay according to a second embodiment. FIG. [Figure 20] FIG. 20 is a cross-sectional view taken along the line AB in FIG. 19. [Figure 21] 10 is a schematic diagram showing another arrangement of adjacent pixel units in the microdisplay of Example 2. FIG. [Figure 22] FIG. 22 is a cross-sectional view taken along the CD cross section of FIG. 21. [Figure 23]FIG. 10 is a cross-sectional view showing a common cathode shared between adjacent pixel units in the second embodiment. [Figure 24] FIG. 10 is a top view of a pixel-level discrete element according to a third embodiment. [Figure 25] 25 is a cross-sectional view taken along the xx direction in FIG. 24. [Figure 26] FIG. 25 is a developed view of the AB cross section of FIG. 24. [Figure 27] FIG. 10 is another cross-sectional view of Example 3 in the xx direction (the sacrificial layer is not removed and there is no blocking support structure). [Figure 28] FIG. 11 is a top view of a back plate on which a pad is provided in Example 3. [Figure 29] FIG. 29 is a cross-sectional view in the CD direction of FIG. 28 (including the sacrificial layer and the solid pad). [Figure 30] FIG. 29 is another cross-sectional view in the CD direction of FIG. 28 (including the sacrificial layer and hollow pads). DETAILED DESCRIPTION OF THE INVENTION

[0045] In order to clarify the purpose, technical means and advantages of the present application, the following will clearly and completely describe the technical means in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and are not all of the embodiments. Based on the embodiments of the present application, all other embodiments that a person skilled in the art can obtain without any creative effort are all within the scope of protection of the present application.

[0046] In this description, orientations or positional relationships indicated by terms such as "upper," "lower," "inner," and "outer" are based on the orientations or positional relationships shown in the drawings and are for the convenience and simplification of explanation. They do not indicate or imply that the referenced devices or elements must have a particular orientation or be constructed or operated in a particular orientation, and therefore cannot be understood as limiting this application. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In this description, unless otherwise specified, "plurality" means two or more.

[0047] In the description of this application, unless otherwise expressly specified or limited, the terms "attached," "connected to each other," and "connection" should be understood in a broad sense. For example, they may be fixedly connected, detachably connected, or integrally connected. They may be mechanically connected or electrically connected. They may be directly connected, indirectly connected via an intermediate medium, or internally communicated between two elements. Those skilled in the art will be able to understand the specific meanings of the above terms in this application on a case-by-case basis.

[0048] Example 1 As shown in Figures 1 to 5, this embodiment provides a pixel unit 100 for use in a semiconductor device. The pixel unit 100 includes a backplane 10, a display unit 20, and a common cathode 30. The pixel unit 100 according to this embodiment is a vertical stack pixel (hereinafter referred to as VSP). The pixel unit 100 can be used in semiconductor devices such as microdisplays and invisible light detectors.

[0049] Note: Figure 1 is a top view of the pixel unit 100, and the dotted line represents its main internal structure, and the same applies below. Figures 2 to 5 are two cross-sectional views of Figure 1 (top view), and the subsequent structural views are all top views or corresponding cross-sectional views of the current structure. The xx cross-sectional view is a cross-sectional view in the horizontal direction of the top view, and the yy cross-sectional view is a cross-sectional view in the vertical direction of the top view.

[0050] Specifically, the back plate 10 is provided with a driving circuit. The driving circuit 10 is provided with at least one anode. Exemplarily, a circuit diagram of the driving circuit is shown in FIG. 6. Note that the circuit diagrams in this embodiment are simplified schematic diagrams and are all active driving. The internal circuit of the pixel unit 100 may include active, passive, or semi-passive control circuits. Exemplarily, FIG. 7 is a circuit diagram of any one of the element layers. In this embodiment, the anodes may be arranged in a collinear arrangement, a rectangular arrangement, or an array arrangement. Any of the anodes may be located in the middle or at the edge of the back plate 10, but this embodiment is not limited thereto.

[0051] 1 to 5, the display unit 20 is provided on one surface of the back plate 10 on which at least one anode is provided. The display unit 20 includes a first element layer 40 and a second element layer 50 that are stacked vertically along a direction away from the back plate 10. The first element layer 40 includes a first compound light-emitting layer 41 and a second compound light-emitting layer 42 that are provided adjacent to each other. The second element layer 50 includes a color conversion layer 51 and a third compound light-emitting layer 52 that are provided adjacent to each other. The color conversion layer 51 is provided above the first compound light-emitting layer 41.

[0052] It should be noted that any of the element layers in this embodiment may have a general shape such as a square, a hexagon, an octagon, a circle, or a combination of shapes, and this embodiment does not further limit this.

[0053] Of course, in this embodiment, the materials of each compound light-emitting layer used in the display unit 20 may be the same or different. Exemplary combinations may be as follows: The color conversion layer 51 is made of a red quantum dot material, and the first compound light-emitting layer 41, the second compound light-emitting layer 42, and the third compound light-emitting layer 52 are made of the same or different light sources other than red light, preferably one of ultraviolet light, blue light, and green light. Here, the wavelength of the light source of the first compound semiconductor layer 412 is shorter than the wavelength of the red light. Note that the compound semiconductor layers in this embodiment all refer to quantum well compound semiconductor layers.

[0054] Furthermore, the number of element layers stacked vertically in the display unit 20 includes, but is not limited to, two layers, and may be three, four, or more layers, as long as all of them are transparent layers in the vertical direction of the color conversion layer 51 and do not block the light of the color conversion layer 51 or cause significant light loss.

[0055] For example, when the compounds of each compound light-emitting layer are different, a multicolor display such as a full-color display can be realized, and when the same compound is used for two or more compound light-emitting layers in the vertical direction, the light irradiation intensity can be enhanced or a redundant structure can be formed. Of course, the two embodiments can coexist in the same display unit 20, and this embodiment is not limited thereto.

[0056] Furthermore, to realize a multicolor display, the first compound light-emitting layer 41, the second compound light-emitting layer 42, and the third compound light-emitting layer 52 are connected to different anodes to realize individual control of light sources of different colors, and the circuit structure is shown in Figure 6. To realize enhanced light irradiation intensity, for example, the same compound light-emitting layers are connected to the same anode, and the connection form can be in series or parallel, and the circuit structure is shown in Figure 8.

[0057] For convenience of explanation, this embodiment will be described in more detail using two element layers as an example. The first compound light emitting layer 41 and the second compound light emitting layer 42 are made of blue-light InGaN compound epitaxy, the third compound light emitting layer 52 is made of green-light InGaN compound epitaxy, and the color conversion layer 51 is made of red-light quantum dot material, thereby realizing RGB full-color display.

[0058] The backplate 10 of this embodiment may be an active backplate that combines one or more of thin film transistors (TFTs), low temperature polysilicon (LTPS), CMOS integrated circuits, high mobility transistors (HEMTs), and the like.

[0059] In this embodiment, a CMOS integrated circuit backplate is selected. The backplate 10 includes at least one top metal 11 covering at least one anode (FIG. 9). Alternatively, the backplate 10 may include an in-situ reflector 12 disposed on its upper surface, covering or exposing at least one anode (FIG. 10). The in-situ reflector 12 may be a metal such as aluminum, gold, or silver. It may also be a Bragg reflector layer made of two or more thin films with different refractive indices, such as a silicon oxide / titanium oxide stack, a silicon oxide / alumina stack, or a silicon oxide / silicon nitride stack. It may also be an ODR total reflector made of a metal and a dielectric stack, such as at least one combination of silver / silicon oxide, aluminum / alumina, or gold / silicon oxide. For example, reflectance data in the visible light wavelength range for a stack of metal aluminum 250 nm and silicon oxide 150 nm (target wavelength 620 nm, 1 / 4 is 150 nm) is shown in FIG. 11.

[0060] The in-situ reflector 12 may be a polygonal structure such as a circle, triangle, square, pentagon, hexagon, or octagon, or may be a combined polygon that avoids the anode contact. The polygon may be inscribed in the pixel boundary or may be reduced from the boundary by a certain length.

[0061] In this embodiment, the common cathode 30 is provided in the circumferential direction of the display unit 20. The common cathode 30 is connected to each of the first compound light-emitting layer 41, the second compound light-emitting layer 42, and the third compound light-emitting layer 52, and is also connected to an external cathode (not shown). The material of the common cathode 30 is a metal such as Cu or Al.

[0062] Specifically, the common cathode 30 is a metal surrounding frame arranged in the circumferential direction 20 of the display unit, and includes a first cathode electrical connection structure 31 connected to the first compound light-emitting layer 41, a second cathode electrical connection structure 32 connected to the second compound light-emitting layer 42, and a third cathode electrical connection structure 33 connected to the third compound light-emitting layer 52.

[0063] 12 to 14, the pixel unit 100 further includes an enhanced common cathode 60 connected to the common cathode 30 and surrounding the first region 61 and the second region 62 that are isolated from each other together with the common cathode 30. A portion of the enhanced common cathode 60 is provided between the third compound light-emitting layer 52 and the color conversion layer 51, and a portion of the enhanced common cathode 60 is provided between the first compound light-emitting layer 41 and the second compound light-emitting layer 42.

[0064] The first compound light-emitting layer 41 and the color conversion layer 51 are stacked in a first region 61, and the second compound light-emitting layer 42 and the third compound light-emitting layer 52 are stacked in a second region 62. The material of the enhanced common cathode 60 is a metal such as Cu or Al.

[0065] The first element layer 40 further includes a first bonding layer 43, a first anode electrical connection structure 44, a second anode electrical connection structure 45, and a first insulating coating layer 46. The first bonding layer 43 is provided on the back plate 10, and the first compound light-emitting layer 41 and the second compound light-emitting layer 42 are each provided on one side of the first bonding layer 43, spaced from the back plate 10. The first anode electrical connection structure 44 has one end connected to the corresponding first anode 13, and the other end connected to the first compound light-emitting layer 41. The second anode electrical connection structure 45 has one end connected to the corresponding second anode 14, and the other end connected to the second compound light-emitting layer 42.

[0066] The first insulating coating layer 46 also covers the first compound light-emitting layer 41, the second compound light-emitting layer 42, the first anode electrical connection structure 44, the second anode electrical connection structure 45, and part of the common cathode 30. The part of the common cathode 30 includes, but is not limited to, the first cathode electrical connection structure 31 and the second cathode electrical connection structure 32.

[0067] The first bonding layer 43 is made of an insulating material, including a dielectric material such as SiO2, Si3N4, Al2O3, or AlN, and may also be a semiconductor material such as Si, or an organic material such as SU8 or BCB. The first insulating coating layer 46 is made of a transparent insulating material such as SiO2. All anode and cathode electrical contact structures are made of corresponding metals such as Cu and Al.

[0068] Furthermore, the first compound light-emitting layer 41 includes a first P-type ohmic contact layer 411, a first compound semiconductor layer 412, and a first N-type ohmic contact layer (not shown), which are provided in this order. The first P-type ohmic contact layer 411 is provided in close contact with the first bonding layer 43, and its area is larger than that of the first compound semiconductor layer 412. The first anode electrical connection structure 44 is provided on the side of the first compound semiconductor layer 412, and a portion of the first anode electrical connection structure 44 sequentially passes through the first P-type ohmic contact layer 411 and the first bonding layer 43 to be connected to the corresponding first anode 13. Therefore, the first compound light-emitting layer 41 is connected to the first anode 13 via the first anode electrical connection structure 44. Specifically, one end of the first anode electrical connection structure 44 is connected to the first P-type ohmic contact layer 411, and the other end is connected to the first anode 13. Furthermore, the first compound light-emitting layer 41 is connected to the common cathode 30 by connecting the first N-type ohmic contact layer and the first cathode electrical connection structure 31 .

[0069] The material of the first p-type ohmic contact layer 411 may be a transparent conductive material such as ITO, or may be a laminate or alloy of metal materials such as Au, Ni, Ag, and Mg. The first p-type ohmic contact layer 411 is formed by coating the first compound semiconductor layer 412 with ITO by vapor deposition, sputtering, or the like. It is preferable that the ITO film thickness is 500 nm, and the ohmic contact is formed by high-temperature annealing at 500°C in an N2 environment.

[0070] Furthermore, the second compound light-emitting layer 42 includes a second P-type ohmic contact layer 421, a second compound semiconductor layer 422, and a second N-type ohmic contact layer (not shown), which are provided in this order. The second P-type ohmic contact layer 421 is provided in close contact with the first bonding layer 43, and has a larger area than the second compound semiconductor layer 422. The second anode electrical connection structure 45 is provided on a side of the second compound semiconductor layer 422, and a portion of the second anode electrical connection structure 45 sequentially passes through the second P-type ohmic contact layer 421 and the first bonding layer 43 to be connected to the corresponding second anode 14. Therefore, the second compound light-emitting layer 42 is similarly connected to the second anode 14 via the second anode electrical connection structure 45. Specifically, one end of the second anode electrical connection structure 45 is connected to the second P-type ohmic contact layer 421, and the other end is connected to the second anode 14. Furthermore, the second compound light-emitting layer 42 is connected to the common cathode 30 by connecting the second N-type ohmic contact layer and the second cathode electrical connection structure 32 .

[0071] The second element layer 50 further includes a second bonding layer 53, a third anode electrical connection structure 54, and a second insulating coating layer 55. The second bonding layer 53 is provided in close contact with the first element layer 40. The color conversion layer 51 and the third compound light-emitting layer 52 are each provided on one side of the second bonding layer 53, spaced from the first element layer 40. The projected area of the color conversion layer 51 on the back plate 10 is preferably larger than the projected area of the first compound light-emitting layer 41 on the back plate 10.

[0072] The color conversion layer 51 used in this embodiment is used to obtain a target color light source. Specifically, the target color light source is formed by converting the light emitted from the first compound light-emitting layer 41 into a target color when the light passes through the color conversion layer 51. The color conversion layer 51 uses a photochromic material, preferably at least one of a quantum dot material and a phosphor material. Since the color conversion layer 51 in this embodiment is used to form a red light source, the color conversion layer 51 preferably uses a red quantum dot material or a red phosphor material. Here, the red quantum dot material may be a perovskite red quantum dot (the quantum dot material may be at least one of a CsPdI3 material, an InP material, a CdSe material, or a CdS material). Based on this, the wavelength of the light source of the first compound semiconductor layer 412 is shorter than the wavelength of red light so as to transmit the light of the first compound semiconductor layer 412.

[0073] Here, the second bonding layer 53 is made of a transparent insulating material such as SiO2. The second insulating coating layer 55 is made of a transparent insulating material such as SiO2. All anode and cathode electrical connection structures are made of corresponding metals such as Cu and Al.

[0074] The third compound light-emitting layer 52 includes a third P-type ohmic contact layer 521, a third compound semiconductor layer 522, and a third N-type ohmic contact layer (not shown). The third P-type ohmic contact layer 521 is provided in close contact with the second bonding layer 53, and has a larger area than the third compound semiconductor layer 522. The third anode electrical connection structure 54 is provided on a side of the third compound semiconductor layer 522, and a portion of the third anode electrical connection structure 54 sequentially passes through the third P-type ohmic contact layer 521, the second bonding layer 53, and the first bonding layer 43 to be connected to the corresponding third anode 15. Therefore, one end of the third anode electrical connection structure 54 is connected to the third P-type ohmic contact layer 521, and the other end is connected to the third anode 15, thereby realizing connection between the third compound light-emitting layer 52 and the third anode 15. The third cathode electrical connection structure 33 and the third N-type ohmic contact layer are connected to each other, thereby realizing connection between the third compound light-emitting layer 52 and the common cathode 30.

[0075] The second insulating coating layer 55 also covers the color conversion layer 51, the third compound light-emitting layer 52, the third anode electrical connection structure 54, and part of the common cathode 30. The part of the common cathode 30 here includes, but is not limited to, the third cathode electrical connection structure 33.

[0076] Preferably, as shown in FIG. 14 , in order to reduce the absorption and loss of light emitted from the second compound light emitting layer 42 by the third compound light emitting layer 52, the projected area of the third compound light emitting layer 52 on the backplate 10 is smaller than that of the second compound light emitting layer 42, and the size of each light emitting layer can be adjusted according to the mixing ratio of different colors.

[0077] For example, as shown in FIG. 15, a typical microdisplay element has a pixel size of 2 μm, taking a monochrome pixel size of 4 μm as an example. When the RGB elements are stacked horizontally, the pixel size is 4*12 μm, and when stacked in a rectangular shape, the pixel size is 8*8 μm. Here, the brightness of the red AlGaInP element is 200,000 nits (approximately 20 mW), the brightness of the green InGaN element is 3 million nits (approximately 120 mW), and the brightness of the blue InGaN element is 500,000 nits (approximately 120 mW). The required white light is composed of three colors: red, green, and blue, with the proportions being 35% red, 50% green, and 15% blue. The combined brightness of the white light is significantly affected by the red and blue elements, with the brightness of the red light being particularly lacking. In one embodiment, the first compound light-emitting layer 41 (backlight source) and the second compound light-emitting layer 42 emit blue light, and the third compound light-emitting layer 52 emits green light. By adjusting and combining the pixel sizes (areas), the sizes of the first compound light-emitting layer 41 and the second compound light-emitting layer 42 are increased, while the size of the sub-pixel elements of the third compound light-emitting layer 52 is decreased, thereby achieving a better blending ratio. The quantum dot material used is perovskite red quantum dots (the quantum dot material may be a CsPdI3 material, an InP material, a CdSe material, or a CdS material), and the conversion efficiency of the CsPdI3 material exceeds 80%. The pixel size is 5 × 5 μm, the pixel size of the blue light as the backlight source is 2.5 × 4 μm, the size of the sub-pixel as the blue primary color is 1.5 × 4 μm, and the size of the sub-pixel as the green primary color is 1 × 4 μm. The brightness after color conversion is 1.2 million nits (approximately 240MW) for red light, 3 million nits (approximately 120MW) for green light, and 750,000 nits (approximately 180MW) for blue light, achieving a significant improvement in brightness while reducing the pixel size.

[0078] By separating the first compound light-emitting layer 41 and the color conversion layer 51 by a certain distance, thermal isolation is achieved and a decrease in thermal stability due to direct contact between the photochromic material of the color conversion layer 51 and the backlight source is avoided. The distance can be determined based on the thickness of the second bonding layer 53 and the thickness of the color conversion layer 51, and is not specifically limited in this embodiment. The distance is preferably 0.1 to 5 μm. Of course, components that achieve the thermal isolation effect include, but are not limited to, the first insulating coating layer 46 and the second bonding layer 53.

[0079] The display unit 20 further includes a water vapor blocking layer 70 disposed on the surface of the second element layer 50. Specifically, the water vapor blocking layer 70 is made of a transparent dielectric material. The transparent dielectric material may be a single layer or multiple layers of an inorganic dielectric material such as silicon oxide, silicon nitride, alumina, titanium oxide, or diamond, or may be an organic dielectric material such as SU8 or polyimide, or a polycrystalline material such as glass or soda. Preferably, the water vapor blocking layer 70 is a Bragg reflector layer formed by laminating silicon oxide and titanium oxide, and the water vapor blocking layer 70 on the surface of the third compound light-emitting layer 52 is removed by etching. The water vapor blocking layer 70 can act as a light filter, transmitting only light in the red wavelength range.

[0080] The pixel unit 100 further includes an optical reinforcement structure 80. Specifically, as shown in Fig. 16, the optical reinforcement structure 80 is laminated on the surface of the water vapor barrier layer 70. The optical reinforcement structure 80 may be a polarizer, a lens, etc. The lens may be an organic material such as SU8 or polyimide, or an inorganic material such as silicon oxide or alumina.

[0081] Corresponding to the above pixel unit 100, this embodiment further provides a method for manufacturing a pixel unit used in a semiconductor device. The method includes:

[0082] In S1, a backboard is prepared.

[0083] Specifically, the backplate may be one or more active backplates such as thin film transistors (TFTs), low temperature polysilicon (LTPS), CMOS integrated circuits, high mobility transistors (HEMTs), etc. A CMOS integrated circuit backplate including at least one anode is selected. Of course, the surface of the backplate is provided with at least one top metal covering the anode, or an in-situ reflector provided on the surface of the backplate. In this embodiment, it is preferable to provide a top metal.

[0084] In S2, a display unit is manufactured by bonding a first target compound semiconductor prepared in advance to a back plate so as to form a first bonding layer, constructing a first compound light-emitting layer and a second compound light-emitting layer adjacent to each other so as to form a first element layer, and then bonding a second target compound semiconductor prepared in advance to one side of the first element layer spaced from the back plate so as to form a second bonding layer, constructing a third compound light-emitting layer and a color conversion layer adjacent to the third compound light-emitting layer and above the first compound light-emitting layer so as to form a second element layer.

[0085] Specifically, step S2 includes:

[0086] In S21, a first target compound semiconductor prepared in advance is bonded to a back plate, and includes:

[0087] In S211, an insulating material (bonding material) is coated on the entire surface of the back plate on which at least one anode is provided, and at least one through-hole corresponding to the at least one anode is formed.

[0088] In S212, a first p-type ohmic contact layer is formed on the surface of the first target compound semiconductor, and the entire surface of the first p-type ohmic contact layer is coated with an insulating material (bonding material).

[0089] Preferably, the first target compound semiconductor is an InGaN ternary compound, and its structure may be any one of blue light, green light, etc. wavelength compound structures as shown in the following Table 1 or Table 2. The first target semiconductor compound in this embodiment is preferably a blue light compound.

[0090] [Table 1]

[0091] [Table 2]

[0092] The quantum well compound semiconductor layer is the compound semiconductor layer of this embodiment. The etching cutoff layer has a certain height ratio with respect to the substrate. The etching cutoff layer is used to protect the remaining compound when removing the substrate.

[0093] Therefore, before step S212, the manufacturing method further requires preparing a first target compound semiconductor in advance, and specifically includes:

[0094] Select blue light InGaN ternary compound whose substrate is material such as Si, sapphire, Ga2O3.

[0095] A P-type ohmic contact thin film is formed on the P contact surface. The P-type contact material may be a transparent conductive material such as ITO or ZnO, or a laminate or alloy of metal materials such as Ni, Au, or Ag. For example, ITO is coated by vapor deposition or sputtering to a thickness of 500 nm, and a first P-type ohmic contact layer is formed by high-temperature annealing at 500°C in an N2 environment. Of course, the thickness of the first P-type ohmic contact layer and the conditions for forming the contact layer can be adjusted and changed as needed.

[0096] An insulating material is coated over the entire surface of one side of the first p-type ohmic contact layer of the first target compound semiconductor.

[0097] In S213, the back plate and the first target compound semiconductor are bonded together. Specifically, the surface of the back plate on which the insulating material is provided is bonded to the surface of the first target compound semiconductor on which the insulating material is provided, so as to form a first bonding layer.

[0098] Preferably, the surface of the insulating material is planarized by CMP (chemical mechanical planarization) (surface roughness after CMP planarization is ≦10 nm), and the surface of the insulating material is activated by plasma to make it hydrophilic (plasma activation is performed in an Ar plasma atmosphere with a power of 200 W for 3 minutes), and then the first layer compound is vertically stacked at low temperature, and the first target compound semiconductor is bonded to the backplate for integration.

[0099] For example, in an actual manufacturing process, as shown in Figure 17, a compound wafer is cut, and a compound semi-finished product that is slightly larger (≥ 10 μm) than the display pixel area (display unit) of the backplate is bonded and integrated into a chip-size package. The chip-size package may be a one-chip package as shown in a, a two-chip package as shown in b, a four-chip package as shown in c, or a nine-chip package as shown in d. In a specific implementation, after completing the P-type ohmic contact and bonding layer using a compound wafer, area screening is performed through testing, and the non-defective area is screened and cut to obtain a chip-size package semi-finished product, which is then bonded and integrated through rough alignment bonding.

[0100] In S214, the substrate of the first target compound semiconductor is removed so that the N-type ohmic contact layer of the first target compound semiconductor is exposed.

[0101] Specifically, after the bonding is completed, the blue light compound substrate (Si substrate) is thinned by polishing, and the compound Si substrate is completely removed by SF6 polishing or etching (dry etching or wet etching) to expose the N-type ohmic contact layer (GaN compound).

[0102] In S22, a first compound light-emitting layer and a second compound light-emitting layer are constructed adjacent to each other to form a first device layer, the first compound light-emitting layer including:

[0103] In S221, the first target compound semiconductor, with the N-type ohmic contact layer exposed, is divided into a first compound light-emitting layer and a second compound light-emitting layer that are provided adjacent to each other by patterning etching, and a portion of the first compound light-emitting layer is etched into a first P-type ohmic contact layer and a portion of the second compound light-emitting layer is etched into a second P-type ohmic contact layer.

[0104] In S222, the first compound light-emitting layer and the second compound light-emitting layer are entirely coated with SiO by atomic layer deposition (ALD) to form a first insulating coating layer.

[0105] In S223, the first insulating coating layer is patterned and etched to respectively form a first anode electrical connection channel, a second anode electrical connection channel, a first cathode electrical connection channel, and a second cathode electrical connection channel.

[0106] In S224, a metal coating is applied to the surface of the first insulating coating layer to form a first anode electrical connection structure, a second anode electrical connection structure, a first cathode electrical connection structure, and a second cathode electrical connection structure, respectively, where the first anode electrical connection structure is connected to the first anode, the second anode electrical connection structure is connected to the second anode, and the first cathode electrical connection structure and the second cathode electrical connection structure are respectively connected to the cathode.

[0107] In this embodiment, the pseudo-damascene process is used to passivate and prepare for the next step of bonding during the fabrication of the device and the construction of the cathode and anode electrical connection structures. In a specific implementation, the pseudo-damascene process involves fabricating the device layer through patterned etching, then introducing an insulating coating layer, and finally fabricating the first anode electrical connection structure, the second anode electrical connection structure, the first cathode electrical connection structure, and the second cathode electrical connection structure through patterned deposition or patterned etching.

[0108] In S23, a second target compound semiconductor, which has been prepared in advance to form a second bonding layer, is bonded to one side of the first device layer spaced apart from the back plate, and includes:

[0109] In step S22, after the construction of the first element layer is completed, the construction of the second element layer is performed. As described in step S21, a second target compound semiconductor for forming the third target compound layer must first be prepared. In this embodiment, the second target compound semiconductor is a green-light-emitting semiconductor with the structure described above. The bonding process in this step is similar to that in step S21 and is therefore not repeated here. The second bonding layer may be made of a transparent insulating material such as a transparent dielectric material such as SiO2, Si3N4, Al2O3, or AlN. It may also be a light-transmitting semiconductor material such as ultrathin Si, or a transparent organic material such as SU8 or BCB. For example, the second target compound semiconductor is a Si-based green-light-emitting compound epitaxy.

[0110] In S24, a third compound light-emitting layer is constructed and filled to form a color conversion layer adjacent to the third compound light-emitting layer, and includes:

[0111] In S241, the second target compound semiconductor with the N-type ohmic contact layer exposed is formed into a third compound light-emitting layer by patterning etching, and a part of the third compound light-emitting layer is etched into a third P-type ohmic contact layer.

[0112] In S242, the surface on which the third compound light-emitting layer is located is entirely coated so as to form a second insulating coating layer.

[0113] In S243, the second insulating coating layer, the second bonding layer, the first insulating coating layer and the first bonding layer are patterned and etched to form a third anode electrical connection channel, a third cathode electrical connection channel and a first slot, respectively.

[0114] In S244, the first slot is filled with a color conversion material to form a color conversion layer on the second bonding layer.

[0115] Specifically, the color conversion material is filled into the first slot by spray printing, spin coating, graphics, engraving, or the like, and then the color conversion material is planarized by CMP planarization or scraping with a scraper.

[0116] In S245, a metal coating is applied to the surface on which the second insulating coating layer is located, so as to form a second element layer, thereby forming a third anode electrical connection structure connected to the third anode and a third cathode electrical connection structure connected to the cathode.

[0117] Similarly, in step 24, a similar damascene process completes the construction of the cathode and anode electrical connection structures.

[0118] At S3, an enhanced common cathode is constructed and includes:

[0119] In S31, the second element layer and the first element layer are patterned and etched to form an enhanced common cathode channel, a portion of which is disposed between the third compound light-emitting layer and the color conversion layer and a portion of which is disposed between the first compound light-emitting layer and the second compound light-emitting layer.

[0120] In S32, a metal coating is applied to the surface of the second device layer to form an enhanced common cathode that is connected to the common cathode and surrounds the first and second regions that are isolated from each other together with the common cathode.

[0121] In step S4, a water vapor barrier material is coated on the surface of the second element layer to form a water vapor barrier layer, specifically, Al2O3 is coated on the surface of the second element layer by the ALD process to form a water vapor barrier layer, which isolates water vapor and enhances the stability of the color conversion material.

[0122] Of course, after step S4, structures such as a black matrix (BM), polarizer, or lens can be added to the surface of the water vapor barrier layer to further control light output. Here, the BM can be a metal or a special black colloid. Polarization can be achieved by a Bragg reflector layer. The lens can be an inorganic dielectric layer or an organic colloid. In one embodiment, a hemispherical lens structure made of SU8 is added for light extraction.

[0123] In summary, the pixel unit used in the semiconductor device according to this embodiment achieves multicolor display by vertically stacking at least two device layers on a backplane. Compared to a pixel structure in which the pixel units are horizontally stacked to achieve full color, the pixel units in this embodiment occupy less horizontal space, effectively reducing the reduction in external quantum efficiency caused by size effects, and effectively reducing power consumption and improving performance such as brightness. Furthermore, by stacking multiple layers vertically, yield can be effectively improved. Furthermore, by providing a color conversion layer, the compound light-emitting layer, which has a significant reduction in external quantum efficiency, can achieve color emission through color conversion, thereby reducing power consumption and improving performance.

[0124] Furthermore, by providing the common cathode in this embodiment in the circumferential direction of the display unit, the area ratio of the cathode in the display unit can be reduced, the area ratio of the light-emitting region can be increased, and the influence of size effects can be reduced. At the same time, the number of stacked element layers in the vertical direction can be increased or redundant circuits can be formed, which effectively prevents optical crosstalk between adjacent pixel units and avoids light leakage from the color conversion layer.

[0125] The pixel unit of this embodiment further includes an enhanced common cathode connected to the common cathode and surrounding the first and second regions, which are isolated from each other, the first compound light-emitting layer and the color conversion layer being stacked in the first region, and the second compound light-emitting layer and the third compound light-emitting layer being stacked in the second region. The enhanced common cathode can effectively enhance electrical reinforcement, prevent optical crosstalk between adjacent compound light-emitting layers, and more importantly, prevent light overflow from the first compound light-emitting layer.

[0126] Furthermore, since the projected area of the color conversion layer on the back plate of this embodiment is larger than the projected area of the first compound light-emitting layer on the back plate, light overflow from the first compound light-emitting layer is prevented.

[0127] In addition, the color conversion layer of this embodiment is made of a red quantum dot material, and the wavelength of the light source of the first compound semiconductor layer is smaller than the wavelength of the red light. Therefore, red light is realized through color conversion so as to avoid the power consumption and performance defects caused by the external quantum effect due to the size effect of the AlGaInP red light system, and the environmental protection issue caused by the GaAs red light system is effectively resolved, while at the same time avoiding the high activity reliability issue due to the ultra-large specific surface area of the green and blue quantum dots.

[0128] Furthermore, the manufacturing method of the pixel unit used in the semiconductor device according to this embodiment uses a similar damascene process in the manufacturing of the device, the cathode electrical connection, and the anode electrical connection to perform passivation and prepare for the next step of bonding. Compared to the conventional method of building an electrical connection structure by etching a metal layer, this method reduces the difficulty of the process of building electrical connections in a stacking method, and improves the feasibility of electrical connection structures, especially for metals (such as copper) that are difficult to dry etch.

[0129] It is sufficient for this embodiment to achieve at least one of the above technical effects.

[0130] Example 2 According to this embodiment, a microdisplay is provided. As shown in Figure 18, the microdisplay 200 includes a driver backplate 300 including at least two driver circuits, an input interface, and an output interface; A display area 400 provided on the driving back plate 300, the display area 400 including at least two display units 20 according to the first embodiment and corresponding common cathodes 30 arranged in an array; and a peripheral common cathode 500 electrically connected to the common cathode 30 of each display unit 20 so that the entire microdisplay 200 is a common cathode. The peripheral common cathode 500 is a metal surrounding frame structure provided around the periphery of the display area 400.

[0131] The external IO interface 600 is located at any position on the drive backplate 300 .

[0132] Furthermore, this embodiment does not limit the orientation of the arrangement of the pixel units 100 adjacent to each other in an array in the microdisplay 200. In one embodiment, an arrangement of four pixel units 100 is shown in Figures 19 and 20, where Figure 20 is a cross-sectional view taken along the AB section of Figure 19. In another embodiment, an arrangement of four pixel units 100 is shown in Figures 21 and 22, where Figure 22 is a cross-sectional view taken along the CD section of Figure 21. By adjusting the orientation of the arrangement of the pixel units 100, jagged edges of the display can be improved, or the display can be enhanced by borrowing neighboring pixels.

[0133] Furthermore, the common cathode 30 of adjacent pixel units 100 may be combined and shared to further increase the size of the pixel unit 100. Exemplarily, a cross-sectional view of two adjacent pixel units 100 is shown in the following FIG.

[0134] For the specific structure and corresponding technical effects of the micro display of this embodiment, please refer to the relevant description in the first embodiment, and further detailed description will be omitted in this embodiment.

[0135] Example 3 As shown in FIGS. 24 to 30 , another pixel unit 100′ is provided according to this embodiment. The pixel unit 100′ includes a back plate 10′, at least four pads, a display unit 20′, a common cathode 30′, an enhanced common cathode 60′, and a blocking support structure 70′. Here, the display unit 20′ is located above the back plate 10′. The common cathode 30′ is disposed in the circumferential direction of the display unit 20′ and connected to any compound light-emitting layer in any device layer of the display unit 20′. At least four pads are connected to the display unit 20′ and are disposed on the back plate 10′ such that at least a portion of each pad is embedded. The display unit 20′ is disposed separately from the back plate 10′. The blocking support structure 70′ covers the display unit 20′ and is connected to the back plate 10′. Note that the structure of the display unit 20' in this embodiment is the same as the structure of the display unit 20 in embodiment 1, and the remaining description of the display unit 20' in this embodiment refers to the description of the display unit 20 in this embodiment and will not be repeated in this embodiment.

[0136] The pixel unit 100' will be described in more detail below with reference to the drawings.

[0137] The material of the back plate 10' can be one of passive substrates such as silicon, PCB, sapphire or glass, or can be an SOI CMOS substrate to complete a single pixel circuit control switch. In this embodiment, a silicon-based back plate is taken as an example for more detailed explanation.

[0138] Since the pads are used to correspond to the preset electrical connection interfaces of downstream packaging products, in this embodiment, the pad structure is not limited, and it is preferable that all pad structures are the same in order to simplify the structure and reduce the difficulty of the process. The pads can be solid or hollow, as shown in Figures 28 to 30.

[0139] The at least four pads include one cathode pad 91 and at least three anode pads. Specifically, taking the cathode pad 91 as an example, as shown in FIG. 26 , the cathode pad 91 includes a first connection portion 911 and a pinhole portion 912 that are connected to each other. Here, the first connection portion 911 is provided on the outside of the back plate 10′ to connect to the display unit 20′, and the pinhole portion 912 is provided inside the back plate 10′. The pinhole portion 912 may have a vertebral structure, a step structure, a cylindrical structure, a rectangular parallelepiped structure, etc. The pads may also be made of alloys or laminates of one or more of gold, titanium, tungsten, aluminum, and platinum. Of course, corresponding to the one cathode pad 91 and at least three anode pads, at least four corresponding grooves are formed in the back plate 10′, and the groove structures formed in the back plate 10′ correspond to the corresponding pad structures. In this embodiment, the back plate 10' and any of the pads are provided separately, that is, the back plate 10' is not in contact with any of the pads.

[0140] 24 to 26, the display unit 20′ includes a first element layer 40′ and a second element layer 50′ stacked vertically along a direction away from the backboard 10′. The first element layer 40′ further includes a first compound light-emitting layer 41′ and a second compound light-emitting layer 42′ disposed adjacent to each other. The second element layer 50′ includes a color conversion layer 51′ and a third compound light-emitting layer 52′ disposed adjacent to each other. The color conversion layer 51′ is disposed above the first compound light-emitting layer 41′. In this manner, the first element layer 40′ serves as a backlight source for the color conversion layer 81. The light source rays of the first compound light-emitting layer 41′ pass through the color conversion layer 51′ and are converted into target light source rays by the color conversion material of the color conversion layer 51′. This reduces the power consumption of the target light source rays and improves brightness.

[0141] Furthermore, the at least three anode pads include a first anode pad 92, a second anode pad 93, and a third anode pad 94. Of course, the number N of anode pads is equal to or greater than the number of compound light-emitting layers in the device layer. The common cathode 30 is connected to the cathode pad 91, the first compound light-emitting layer 41′, the second compound light-emitting layer 42′, and the third compound light-emitting layer 52′, respectively, thereby realizing connection between each compound light-emitting layer and the cathode pad 91.

[0142] The first element layer 40' further includes a first bonding layer 43', a first anode electrical connection structure 44', a second anode electrical connection structure 45', and a first insulating coating layer 46', where the first bonding layer 43' is made of an insulating material. The first compound light-emitting layer 41' and the second compound light-emitting layer 42' are respectively provided on one side of the first bonding layer 43', spaced apart from the backplate 10'. The first anode electrical connection structure 44' has one end connected to the corresponding first anode pad 92 and the other end connected to the first compound light-emitting layer 41'. The second anode electrical connection structure 45' has one end connected to the corresponding second anode pad 93 and the other end connected to the second compound light-emitting layer 42'.

[0143] The first compound light-emitting layer 41′ includes a first P-type ohmic contact layer 411′, a first compound semiconductor layer 412′, and a first N-type ohmic contact layer (not shown). The compound semiconductor layers in this embodiment all refer to quantum well compound semiconductor layers. The first P-type ohmic contact layer 411′ is provided on the first bonding layer 43′, and has a larger area than the first compound semiconductor layer 412′. Preferably, the first anode electrical connection structure 44′ is provided on a side of the first compound semiconductor layer 412′, and a portion of the first anode electrical connection structure 44′ passes through the first P-type ohmic contact layer 411′ and the first bonding layer 43′ in sequence to be connected to the first anode pad 92. The material of the first P-type ohmic contact layer 411′ may be a transparent conductive material such as ITO, or a laminate or alloy of metal materials such as Au, Ni, Ag, or Mg. The first p-type ohmic contact layer 411' is formed by coating the first compound semiconductor layer 412' with ITO by vapor deposition, sputtering, etc. It is preferable that the ITO film thickness is 500 nm, and the ohmic contact is formed by high-temperature annealing at 500°C in an N2 environment.

[0144] The common cathode 30′ includes a first cathode electrical connection structure 31′. The first cathode electrical connection structure 31′ is connected to the first N-type ohmic contact layer, thereby realizing connection between the first compound light-emitting layer 41 and the cathode pad 91.

[0145] Similarly, the second compound light-emitting layer 42' includes a second P-type ohmic contact layer 421', a second compound semiconductor layer 422', and a second N-type ohmic contact layer (not shown). The second P-type ohmic contact layer 421' is provided on the first bonding layer 43', and its area is larger than that of the second compound semiconductor layer 422'. The second anode electrical connection structure 45' is provided on a side of the second compound semiconductor layer 422', and a portion of it sequentially passes through the second P-type ohmic contact layer 421' and the first bonding layer 43' to be connected to the corresponding second anode pad 93.

[0146] In this embodiment, the second anode electrical connection structure 45' is provided on the side of the second compound semiconductor layer 422', and the first anode electrical connection structure 44' is provided on the side of the first compound semiconductor layer 412', thereby preventing the electrical connection structures (the first anode electrical connection structure 44' and the second anode electrical connection structure 45') from blocking the light-emitting surface.

[0147] Moreover, the common cathode 30' further includes a second cathode electrical connection structure 32' connected to the second N-type ohmic contact layer, thereby realizing connection between the second compound light-emitting layer 42' and the cathode pad 91.

[0148] Furthermore, the first insulating coating layer 46' is made of a transparent insulating material such as SiO2. The first insulating coating layer 46' covers the first compound light-emitting layer 41', the second compound light-emitting layer 42', the first anode electrical connection structure 44', the second anode electrical connection structure 45', and a portion of the common cathode 30'. The portion of the common cathode 30' includes, but is not limited to, the first cathode electrical connection structure 31' and the second cathode electrical connection structure 32'.

[0149] The second element layer 50' further includes a second bonding layer 53', a third anode electrical connection structure 54', and a second insulating coating layer 55'. The second bonding layer 53' is made of a transparent insulating material such as SiO2. The second bonding layer 53' is provided on the first element layer 40'. The color conversion layer 51' and the third compound light-emitting layer 52' are each provided on one side of the second bonding layer 53' spaced apart from the first element layer 40'. The projected area of the color conversion layer 51' on the back plate 10' is larger than the projected area of the first compound light-emitting layer 41' on the back plate 10', thereby effectively preventing overflow of light from the first compound light-emitting layer 41'.

[0150] Specifically, the second bonding layer 53' is made of silicon nitride, which is a transparent insulating material. The third compound light-emitting layer 52' includes a third P-type ohmic contact layer 521', a third compound semiconductor layer 522', and a third N-type ohmic contact layer (not shown). The third P-type ohmic contact layer 521' is provided on the second bonding layer 53', and its area is larger than that of the third compound semiconductor layer 522'. The third anode electrical connection structure 54' is provided on a side of the third compound semiconductor layer 522', and a portion of it sequentially penetrates the third P-type ohmic contact layer 521', the second bonding layer 53', and the first bonding layer 43' to be connected to the corresponding third anode pad 94. Similarly, the common cathode 30' includes a third cathode electrical connection structure 33', a third cathode electrical connection structure 33', and a third N-type ohmic contact layer, thereby realizing connection between the third compound light-emitting layer 52' and the cathode pad 91. The second insulating coating layer 55' covers the color conversion layer 51', the third compound light-emitting layer 52', the third anode electrical connection structure 54', and a portion of the common cathode 30'. The portion of the common cathode 30' includes, but is not limited to, the third cathode electrical connection structure 33'. The second insulating coating layer 55' is made of a transparent insulating material such as SiO2.

[0151] All the electrical connection structures of the anodes and the common cathode 30' are made of metallic materials such as Cu, Al, etc.

[0152] The enhanced common cathode 60' is connected to the common cathode 30' and surrounds at least two regions that are isolated from each other, together with the common cathode 30'. Each region includes at least one compound light-emitting layer or color conversion layer 51'. The enhanced common cathode 60' is made of a metal such as Cu or Al, which is a good conductor. In this embodiment, the enhanced common cathode 60' is connected to the common cathode 30' and surrounds a first region 61' and a second region 62' that are isolated from each other, together with the common cathode 30'. A portion of the enhanced common cathode 60' is disposed between the third compound light-emitting layer 52' and the color conversion layer 51', and a portion of the enhanced common cathode 60' is disposed between the first compound light-emitting layer 41' and the second compound light-emitting layer 42'. The first compound light-emitting layer 41' and the color conversion layer 51' are stacked in a first region 61', and the second compound light-emitting layer 42' and the third compound light-emitting layer 52' are stacked in a second region 62'.

[0153] 24 to 26, the blocking support structure 70' includes a covering portion 71' and a fixing portion 72' that are connected to each other. The covering portion 71' covers the display unit 20', and the fixing portion 72' is connected to the back panel 10'. The blocking support structure 70' forms a tether structure to fix and connect the display unit 20' to the back panel 10'.

[0154] Specifically, the coating 71' covers the display unit 20' and is primarily used to provide a water vapor barrier to prevent the color conversion layer 51' from being corroded by water vapor and affecting its performance and lifespan. The coating 71' is made of a transparent dielectric material. Transparent dielectric materials include single or multilayered inorganic dielectric materials such as silicon oxide, silicon nitride, alumina, titanium oxide, and diamond. They may also be organic dielectric materials such as SU8 and polyimide, or polycrystalline materials such as glass and soda. Preferably, the coating 71' is a Bragg reflector layer formed by laminating silicon oxide and titanium oxide. The coating 71' on the surface of the third compound light-emitting layer 52' is removed by etching. The coating 71' can act as an optical filter, transmitting only light in the red wavelength range.

[0155] 27, the display unit 20' is provided separately from the back plate 10', and the at least four pads are provided separately from the back plate 10'. This separation can be achieved by providing a sacrificial layer between the back plate and the at least four pads in advance during the manufacturing process, and then removing the sacrificial layer by etching or other methods after the stacking of elements is completed and the blocking support structure 70' is formed. Therefore, when the pixel unit 100' is moved, it only needs to break the covering portion 71' and the fixing portion 72' by an external force, which is convenient to access. In addition, in this structure, the back plate 10' can be reused, thereby reducing costs.

[0156] In an exemplary structure, the portion of the blocking support structure 70' that is attached to the back plate 10' is completely in contact with the back plate 10', and the edges may be either flush with, exceed, or recessed from the corresponding edges of the back plate 10', although this embodiment is not limited thereto.

[0157] Corresponding to the above-mentioned pixel unit 100', according to this embodiment, there is further provided a method for manufacturing a pixel unit, which includes the following steps.

[0158] In S1', a back plate is prepared.

[0159] Specifically, step S1' includes:

[0160] In S11', a pre-prepared backplate is etched to form at least four cavities.

[0161] In step S12', a sacrificial layer is coated on one side of the back plate where at least four cavities are formed, and the sacrificial layer is formed on the surface of the back plate by coating, thermal oxidation, wet oxidation, etc. using silicon oxynitride.

[0162] In S13', at least four pads are constructed on one side of the backplate coated with the sacrificial layer, including a cathode pad and at least three anode pads, each of which is provided in a corresponding cavity so that a portion of each pad is embedded.

[0163] The pads in this embodiment are metal pads, and may be one or more alloys or laminates of gold, titanium, tungsten, aluminum, and platinum. The manufacturing methods include thermal evaporation, sputtering, electroplating, and chemical plating, and the pads may be solid or hollow.

[0164] In S2', a first target compound semiconductor prepared in advance is bonded to a back plate so as to form a first bonding layer, and a first compound light-emitting layer and a second compound light-emitting layer are constructed adjacent to each other so as to form a first element layer. Thereafter, a second target compound semiconductor prepared in advance is bonded to one side of the first element layer spaced from the back plate, and a third compound light-emitting layer and a color conversion layer provided adjacent to the third compound light-emitting layer and above the first compound light-emitting layer are constructed so as to form a second element layer.

[0165] The at least four pads include a first anode pad, a second anode pad and a third anode pad.

[0166] Specifically, step S2' includes:

[0167] In S21', a first target compound semiconductor prepared in advance is bonded to a back plate, and a first compound light-emitting layer and a second compound light-emitting layer are constructed adjacent to each other to form a first device layer.

[0168] In step S211', an insulating material is coated on the entire surface of the back plate on which at least four pads are provided, and at least one through hole corresponding to any one of the pads is formed.

[0169] In S212', a first p-type ohmic contact layer is formed on the surface of the first target compound semiconductor, and an insulating material is coated on the entire surface of the first p-type ohmic contact layer.

[0170] The first target compound semiconductor is preferably an InGaN ternary compound, and therefore, before step S212′, the manufacturing method requires that the first target compound semiconductor be manufactured in advance. For details, see the description in Example 1.

[0171] In S213', the back plate and the first target compound semiconductor are bonded together.

[0172] In S214', the substrate of the first target compound semiconductor is removed so that the N-type ohmic contact layer of the first target compound semiconductor is exposed.

[0173] In S215', the first target compound semiconductor with the exposed N-type ohmic contact layer is divided into adjacent first and second compound light-emitting layers by patterning etching, and a portion of the first compound light-emitting layer is etched into a first P-type ohmic contact layer, and a portion of the second compound light-emitting layer is etched into a second P-type ohmic contact layer. In this manner, adjacent first and second compound light-emitting layers are formed. The first compound light-emitting layer includes a first P-type ohmic contact layer, a first compound semiconductor layer, and a first N-type ohmic contact layer, which are sequentially and closely arranged, and the second compound light-emitting layer includes a second P-type ohmic contact layer, a second compound semiconductor layer, and a second N-type ohmic contact layer, which are sequentially and closely arranged.

[0174] In S216', the first compound light-emitting layer and the second compound light-emitting layer are entirely coated with SiO to form a first insulating coating layer. For example, the first compound light-emitting layer and the second compound light-emitting layer are coated with SiO by an atomic layer deposition (ALD) process to form the first insulating coating layer.

[0175] In S217', the first insulating coating layer is patterned and etched to respectively form a first anode electrical connection channel, a second anode electrical connection channel, a first cathode electrical connection channel, and a second cathode electrical connection channel.

[0176] In S218', a metal coating is applied to the surface of the first insulating coating layer, so as to respectively form a first anode electrical connection structure, a second anode electrical connection structure, a first cathode electrical connection structure, and a second cathode electrical connection structure.

[0177] In S22', a third compound light-emitting layer is constructed and filled to form a color conversion layer adjacent to the third compound light-emitting layer.

[0178] In S221', the second target compound semiconductor with the N-type ohmic contact layer exposed is patterned and etched to form a third compound light-emitting layer, and a portion of the third compound light-emitting layer is etched to form a third P-type ohmic contact layer. The second target compound semiconductor in this example is a silicon-based green light-emitting compound epitaxy, and its structure is described in S212. In this manner, a third compound light-emitting layer is formed. The third compound light-emitting layer includes a third P-type ohmic contact layer, a third compound semiconductor layer, and a third N-type ohmic contact layer, which are sequentially and closely arranged.

[0179] In S222', the surface on which the third compound light-emitting layer is located is entirely coated so as to form a second insulating coating layer.

[0180] In S223', the second insulating coating layer, the second bonding layer, the first insulating coating layer and the first bonding layer are patterned and etched to respectively form a third anode electrical connection channel, a third cathode electrical connection channel and a first slot.

[0181] In step S224', a color conversion material is filled into the first slot to form a color conversion layer on the second bonding layer. Specifically, the color conversion material is filled into the first slot by spray printing, spin coating, patterning, embossing, or the like, and then planarized by CMP planarization or scraping.

[0182] In S225', a metal coating is applied to the surface on which the second insulating coating layer is located, so as to form a second element layer, thereby forming a third anode electrical connection structure connected to the third anode and a third cathode electrical connection structure connected to the cathode.

[0183] In a preferred embodiment, after completing step S2', the method further includes step S3' of constructing an enhanced common cathode, including:

[0184] In S31', the second element layer and the first element layer are patterned and etched to form an enhanced common cathode channel, a portion of which is disposed between the third compound light-emitting layer and the color conversion layer and a portion of which is disposed between the first compound light-emitting layer and the second compound light-emitting layer.

[0185] In S32', a metal coating is applied to the surface of the second device layer to form an enhanced common cathode that is connected to the common cathode and surrounds the first and second regions that are isolated from each other together with the common cathode.

[0186] After completing step S2' or S3', the manufacturing method further includes step S4' of forming an isolation support structure, which includes:

[0187] In step S41', a water vapor barrier material is coated on the surface of the second element layer to form a water vapor barrier layer. The barrier support structure includes a covering portion and a fixing portion connected to each other. The covering portion covers the display unit, and the fixing portion is connected to the back plate.

[0188] Specifically, the ALD process is used to coat the surface of the second element layer and part of the backplate with Al2O3, forming a covering that isolates water vapor, enhances the stability of the color conversion material, and simultaneously completes the fixed connection between the display unit and the backplate.

[0189] In step S42', the sacrificial layer is etched from one surface of the back plate that is not coated with the dielectric material, such that at least four pads are separated from the back plate. The etching rate ratio between the sacrificial layer and the back plate is greater than 10:1, and the etching rate ratio between the sacrificial layer and the blocking support structure is greater than 10:1. Preferably, the gap between the etched back plate and the display unit is 100 nm to 1000 nm, and preferably 300 nm to 500 nm.

[0190] In summary, this embodiment provides at least two vertically stacked device layers on a backplate, thereby reducing the size and number of pixel-level individual devices in the horizontal direction, thereby avoiding loss of pixel density, and reducing the number of chip movements during mass transfer, thereby improving precision and yield, while reducing the number of mass transfers, thereby reducing costs. Furthermore, by providing a color conversion layer, the compound luminescent layer, which has a significantly reduced external quantum efficiency, can emit color through color conversion, thereby reducing power consumption and improving performance, thereby achieving full-color display.

[0191] Furthermore, in this embodiment, by providing a common cathode, the area ratio of the cathode in the display unit is reduced, the area ratio of the light-emitting region is increased, and the influence of the size effect is reduced. At the same time, the number of stacked element layers in the vertical direction can be increased or a redundant circuit can be formed, which effectively prevents optical crosstalk between adjacent pixel units and avoids light leakage from the color conversion layer.

[0192] In addition, the pixel unit of this embodiment is connected to an external circuit based on at least four pads, and by sealing the individual elements to the target backplate and making electrical connections through the pads, the process can be simplified and metal welding such as eutectic can be avoided to avoid affecting the performance of the pixel-level individual elements themselves.

[0193] In this embodiment, the display unit is separated from the back plate, and the at least four pads are separated from the back plate. The pixel-level discrete elements further include a shielding support structure covering the display unit and a portion of the back plate. The shielding support structure protects the pixel-level discrete elements from color conversion and prevents performance from being affected by water vapor corrosion. Separating the display unit from the back plate improves structural stability and facilitates access for future use. This structure allows the back plate to be reused, thereby reducing costs.

[0194] The pixel unit of this embodiment further includes an enhanced common cathode connected to the common cathode and surrounding the first and second regions, which are isolated from each other, the first compound light-emitting layer and the color conversion layer being stacked in the first region, and the second compound light-emitting layer and the third compound light-emitting layer being stacked in the second region. The enhanced common cathode can effectively enhance electrical reinforcement, prevent optical crosstalk between adjacent compound light-emitting layers, and more importantly, prevent light overflow from the first compound light-emitting layer.

[0195] Furthermore, the color conversion layer of this embodiment is made of red quantum dot material, and the wavelength of the light source of the first compound semiconductor layer is smaller than the wavelength of the red light. Therefore, red light can be achieved through color conversion, avoiding the power consumption and performance defects caused by external quantum effects due to the size effect of the AlGaInP red light system, while also effectively resolving the environmental protection issues caused by the GaAs red light system, and at the same time avoiding the high activity reliability issues caused by the ultra-large specific surface area of the green and blue quantum dots.

[0196] It is sufficient for this embodiment to achieve at least one of the above technical effects.

[0197] Example 4 According to this embodiment, a pixel level discrete element is provided, the pixel level discrete element comprising: an individual element backplate including at least three anode pads and at least one cathode pad; An element body provided on an individual element backplate, the element body including a display unit included in at least two pixel units described in Example 3, or a display unit included in a pixel unit manufactured by the manufacturing method described in Example 3.

[0198] Any of the above-mentioned technical aspects can be arbitrarily combined to form any embodiment of the present application, i.e., any combination of multiple embodiments can be combined to meet the needs of different application scenarios, all of which are within the scope of protection of the present application and will not be repeated here.

[0199] It should be noted that the above is merely a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. [Explanation of symbols]

[0200] 100,100', pixel unit 10,10', backboard 11. Top Metal 12, In-situ reflector 13. First anode 14. Second anode 15. Third anode 20. Display unit 30,30', common cathode 31, 31', first cathode electrical connection structure 32, 32', second cathode electrical connection structure 33, 33', third cathode electrical connection structure 40, 40', first element layer 41, 41', first compound light-emitting layer 411, 411', first p-type ohmic contact layer 412, 412', first compound semiconductor layer 42, 42', second compound light-emitting layer 421, 421', second P-type ohmic contact layer 422, 422', second compound semiconductor layer 43,43', 1st bonding layer 44, 44', first anode electrical connection structure 45, 45', second anode electrical connection structure 46, 46', first insulating coating layer 50, 50', second element layer 51, 51', color conversion layer 52, 52', third compound light-emitting layer 521, 521', third P-type ohmic contact layer 522, 522', third compound semiconductor layer 53,53', 2nd bonding layer 54, 54', third anode electrical connection structure 55, 55', second insulating coating layer 60,60', reinforced common cathode 61,61', 1st area 62,62', second area 70. Water vapor barrier layer 70', Isolation support structure 71', coating part 72', fixed part 80, Optical reinforcement structure 80', sacrificial layer 200, Microdisplay 300, drive back plate 400, display area 500, ambient common cathode 600, external IO interface

Claims

1. A pixel unit used in a semiconductor device, The backboard and a display unit provided on the back plate, the display unit including a first element layer and a second element layer stacked vertically in sequence along a direction away from the back plate, the first element layer including a first compound light-emitting layer and a second compound light-emitting layer provided adjacent to each other, the second element layer including a color conversion layer and a third compound light-emitting layer provided adjacent to each other, the color conversion layer being provided above the first compound light-emitting layer; A pixel unit characterized by:

2. The display unit further includes a common cathode disposed in a circumferential direction thereof, the common cathode is connected to the first compound light-emitting layer, the second compound light-emitting layer, and the third compound light-emitting layer, and is also connected to an external cathode; The pixel unit according to claim 1 .

3. The cathode further includes an enhanced common cathode connected to the common cathode and surrounding the first and second regions, the first and second regions being isolated from each other together with the common cathode; the first compound light-emitting layer and the color conversion layer are stacked in the first region, the second compound light-emitting layer and the third compound light-emitting layer are stacked on the second region; The pixel unit according to claim 2 .

4. the first element layer further includes a first bonding layer made of an insulating material; the first bonding layer is provided on the back plate, the first compound light-emitting layer and the second compound light-emitting layer are each provided on one side of the first bonding layer spaced from the back plate; The pixel unit according to claim 2 .

5. the first device layer further includes a first anode electrical connection structure and a second anode electrical connection structure; the first anode electrical connection structure has one end connected to the first compound light-emitting layer and the other end extending toward the back plate; the second anode electrical connection structure has one end connected to the second compound light-emitting layer and the other end extending toward the back plate; 5. The pixel unit according to claim 4.

6. the first compound light emitting layer includes a first P-type ohmic contact layer, a first compound semiconductor layer, and a first N-type ohmic contact layer, which are sequentially provided; the first P-type ohmic contact layer is provided in close contact with the first junction layer and has an area larger than an area of the first compound semiconductor layer; the first anode electrical connection structure is provided on a side of the first compound semiconductor layer, and a portion thereof sequentially penetrates the first P-type ohmic contact layer and the first bonding layer; 6. The pixel unit according to claim 5.

7. the common cathode includes a first cathode electrical connection structure connected to the first N-type ohmic contact layer; The pixel unit according to claim 6 .

8. the second element layer further includes a second bonding layer made of a transparent insulating material; the second bonding layer is provided on the first element layer; the color conversion layer and the third compound light-emitting layer are each provided on one side of the second bonding layer spaced apart from the first element layer; 6. The pixel unit according to claim 5.

9. the color conversion layer is provided on the second bonding layer, and a projected area of the color conversion layer on the back plate is larger than a projected area of the first compound light-emitting layer on the back plate; The pixel unit according to claim 8 .

10. The color conversion layer uses a photochromic material, the wavelength of the light source for the first compound semiconductor layer is shorter than the wavelength of the light for the color conversion layer; The pixel unit according to claim 9 .

11. The color conversion layer uses at least one of a red light quantum dot material or a red phosphor material. The pixel unit according to claim 10 .

12. the second device layer further includes a third anode electrical connection structure disposed laterally on the third compound semiconductor layer; the third anode electrical connection structure has one end connected to the third compound light-emitting layer and the other end extending toward the back plate; The pixel unit according to claim 8 .

13. the display unit further includes a first insulating coating layer and a second insulating coating layer, both of which are made of a transparent insulating material; the first insulating coating layer covers the first compound light-emitting layer, the second compound light-emitting layer, the first anode electrical connection structure, the second anode electrical connection structure, a portion of the third anode electrical connection structure, and a portion of the common cathode; the second insulating coating layer covers the color conversion layer, the third compound light-emitting layer, a portion of the third anode electrical connection structure, and a portion of the common cathode; 13. The pixel unit according to claim 12.

14. A drive circuit is provided on the back plate, the driving circuit is provided with at least one anode including a first anode, a second anode, and a third anode; the first anode electrical connection structure is connected to the first anode; the second anode electrical connection structure is connected to the second anode; the third anode electrical connection structure is connected to the third anode; 14. The pixel unit according to claim 12 or 13.

15. the display unit further includes a water vapor barrier layer provided on a surface of the second element layer; 15. The pixel unit according to claim 1, wherein the pixel unit is a pixel unit having a first surface and a second surface.

16. further comprising at least four pads including a cathode pad and at least three anode pads; At least a portion of any one of the at least four pads is provided in the back plate so as to be embedded therein; the common cathode is connected to the cathode pad; the first anode electrical connection structure, the second anode electrical connection structure, and the third anode electrical connection structure are respectively connected to corresponding anode pads among the at least three anode pads; 14. The pixel unit according to claim 12 or 13.

17. the element body is provided separately from the back plate, At least four of the pads are provided separately from the back plate; the pixel level individual element further includes an insulating support structure covering the element body and connected to the backplate; 17. The pixel unit according to claim 16.

18. the blocking support structure includes a covering portion and a fixing portion connected to each other; the covering portion covers the element body, The fixing portion is connected to the back plate.

17. The pixel unit according to claim 16.

19. A manufacturing method for manufacturing the pixel unit according to any one of claims 1 to 15, comprising: Preparing the backboard, manufacturing a display unit by bonding a first target compound semiconductor, which has been prepared in advance, to the back plate so as to form a first bonding layer, constructing a first compound light-emitting layer and a second compound light-emitting layer adjacent to each other to form a first element layer, and then bonding a second target compound semiconductor, which has been prepared in advance to form a second bonding layer, to one side of the first element layer spaced from the back plate, and constructing a third compound light-emitting layer and a color conversion layer adjacent to the third compound light-emitting layer and above the first compound light-emitting layer to form a second element layer, A manufacturing method characterized by:

20. Bonding a first target compound semiconductor prepared in advance to the back plate includes: Coating the entire surface of the back plate on which at least one anode is provided with an insulating material, and forming at least one through hole corresponding to at least one of the anodes; forming a first P-type ohmic contact layer on the surface of the first target compound semiconductor, and coating an insulating material on the entire surface of the first P-type ohmic contact layer; bonding the backplate and the first target compound semiconductor; removing the substrate of the first target compound semiconductor so that an N-type ohmic contact layer of the first target compound semiconductor is exposed; 20. The method of claim 19.

21. Constructing a first compound light-emitting layer and a second compound light-emitting layer adjacent to each other to form a first device layer includes: Dividing the first target compound semiconductor, with the N-type ohmic contact layer exposed, into a first compound light-emitting layer and a second compound light-emitting layer provided adjacent to each other by patterning etching; coating the entire surfaces of the first compound light-emitting layer and the second compound light-emitting layer so as to form a first insulating coating layer; patterning and etching the first insulating coating layer to form a first anode electrical connection channel, a second anode electrical connection channel, a first cathode electrical connection channel, and a second cathode electrical connection channel, respectively; and applying a metal coating to the surface of the first insulating coating layer to form a first anode electrical connection structure, a second anode electrical connection structure, a first cathode electrical connection structure, and a second cathode electrical connection structure, respectively.

21. The method of claim 20.

22. Constructing a third compound light-emitting layer and filling it to form a color conversion layer adjacent to the third compound light-emitting layer, forming a second target compound semiconductor, with an N-type ohmic contact layer exposed, as a third compound light-emitting layer by patterning etching; covering the entire surface on which the third compound light-emitting layer is located so as to form a second insulating coating layer; patterning and etching the second insulating coating layer, the second bonding layer, the first insulating coating layer, and the first bonding layer to respectively form a third anode electrical connection channel, a third cathode electrical connection channel, and a first slot; Filling the first slot with a color conversion material to form a color conversion layer on the second bonding layer; forming a third anode electrical connection structure connected to a third anode and a third cathode electrical connection structure connected to a cathode by performing metal coating on the surface where the second insulating cover layer is located so that the second device layer is formed; 24. The method of claim 23.

23. After the construction of the second layer of devices is completed, patterning and etching the second device layer and the first device layer to form an enhanced common cathode channel, a portion of which is disposed between the third compound light-emitting layer and the color conversion layer and a portion of which is disposed between the first compound light-emitting layer and the second compound light-emitting layer; and performing a metal coating on a surface of the second device layer to form the enhanced common cathode, the enhanced common cathode being connected to the common cathode and surrounding the first and second regions that are isolated from each other together with the common cathode. The method according to any one of claims 19 to 22.

24. After the construction of the second layer of devices is completed, further comprising coating a surface of the second element layer with a water vapor barrier material to form a water vapor barrier layer.

24. The method of claim 23.

25. A manufacturing method for manufacturing the pixel unit according to any one of claims 1 to 12 and 16 to 18, comprising: Preparing the backboard, bonding a first target compound semiconductor prepared in advance to the back plate, constructing a first compound light-emitting layer and a second compound light-emitting layer adjacent to each other to form a first element layer, and then bonding a second target compound semiconductor prepared in advance to one side of the first element layer spaced from the back plate, constructing a third compound light-emitting layer and a color conversion layer adjacent to the third compound light-emitting layer and above the first compound light-emitting layer to form a second element layer. A manufacturing method characterized by:

26. Preparing the backboard Etching a pre-prepared backplate to form at least four cavities; coating a sacrificial layer on one side of the backplate where the at least four cavities are formed; and constructing at least four pads, including a cathode pad and at least three anode pads, on one side of the backplate coated with the sacrificial layer, each pad being provided in a corresponding cavity such that a portion of each pad is embedded.

26. The method of claim 25.

27. After the construction of the second layer of devices is completed, coating a surface of the element body with a dielectric material extending over a portion of the surface of the backplate to form an insulating support structure; etching the sacrificial layer on one surface of the backplate that is not coated with the dielectric material so that at least four of the pads are separated from the backplate; an etching rate ratio between the sacrificial layer and the backplate is greater than 10:1, and an etching rate ratio between the sacrificial layer and the blocking support structure is greater than 10:1; 26. The method of claim 25.

28. a microdisplay backplate including a driving circuit, an input interface, and an output interface; a display area provided on the microdisplay back plate, the display area including at least two display units included in the pixel unit according to any one of claims 1 to 15, which are arranged in an array, or display units included in the pixel unit manufactured by the manufacturing method according to any one of claims 19 to 24; a surrounding common cathode electrically connected to the common cathode of each of the display units, A microdisplay characterized by:

29. an individual element backplate including at least three anode pads and at least one cathode pad; An element body provided on the individual element backplate, the element body including a display unit included in at least two pixel units according to any one of claims 1 to 12 and 16 to 18, or a display unit included in a pixel unit manufactured by the manufacturing method according to any one of claims 25 to 27, 1. A pixel-level discrete element comprising:

Images