Anti-crosstalk micro-display light-emitting pixel

Abstract

The utility model discloses an anti-crosstalk micro-display light-emitting pixel, and relates to the technical field of semiconductors. The micro-display light-emitting pixel comprises a driving back plate and a display module arranged on the driving back plate, the display module comprises a first display device layer and a second display device layer arranged on the first display device layer, the first display device layer comprises a light-emitting unit, a first insulating layer and a first groove structure, and the second display device layer comprises a second insulating layer and a second groove structure; the first insulating layer is formed outside the light-emitting unit in a filling manner; the first groove structure penetrates through the first insulating layer and surrounds the light-emitting unit, the first groove structure is filled with a metal material, and the light-emitting unit is an inorganic compound semiconductor; the second insulating layer is formed on the side, away from the driving backboard, of the first display device layer in a filling mode; the second groove structure penetrates through the second insulating layer, the second groove structure is filled with a metal material, and one end of the second groove structure is connected with the first groove structure.

Description

[0001] The present application claims priority to the Chinese Patent Application No. 202311840767.0, filed on December 29, 2023, and entitled "Anti-crosstalk micro display light emitting pixel and manufacturing method thereof, and micro display screen", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The utility model relates to the technical field of semiconductor, especially to a kind of anti-crosstalk micro display light emitting pixels. BACKGROUND

[0003] In the technical field of semiconductor, the crosstalk between micro display light emitting pixels, light emitting distribution has important influence on display quality, the efficiency of coupling into light waveguide, such as the light emitting angle of normal vertical structure Light Emitting Diode (LED) chip is about ±55 °.

[0004] In the related art, black matrix (BM) or micro lens (MicroLens) manufacturing technology is often used to realize the constraint of crosstalk and light emitting distribution between micro display light emitting pixels. In the black matrix scheme, the black matrix is an organic material system, which has insufficient temperature resistance and mechanical strength, and has defects in reliability. In addition, the black matrix absorbs light, which will cause overall brightness loss. In the micro lens scheme, the prepared micro lens belongs to an organic material system, which has insufficient temperature resistance and mechanical strength, and has defects in reliability. In addition, complete optical isolation between pixels cannot be achieved, and when the pixel size continues to shrink, the ±55 ° light emitting angle will appear before entering the micro lens, that is, the problem of adjacent pixel crosstalk will occur.

[0005] Therefore, there is an urgent need to provide a new micro display light emitting pixel preparation scheme that can avoid the above-mentioned defects. SUMMARY

[0006] The utility model aims at providing a kind of anti-crosstalk micro display light emitting pixel, and light emitting constraint is carried out by the through groove structure, and better optical crosstalk isolation is realized.

[0007] To achieve the above-mentioned utility model purposes, the utility model provides the following technical solutions:

[0008] On the one hand, an anti-crosstalk micro display light emitting pixel is provided, which includes a driving backplate and a display module disposed on the driving backplate.

[0009] The display module comprises a first display device layer and a second display device layer arranged above the first display device layer, the first display device layer comprises a light emitting unit, a first insulating layer and a first trench structure, and the second display device layer comprises a second insulating layer and a second trench structure.

[0010] The first insulating layer is filled in an outer part of the light emitting unit;

[0011] The first trench structure penetrates through the first insulating layer and surrounds the light emitting unit, the first trench structure is filled with a metal material, and the light emitting unit is an inorganic compound semiconductor.

[0012] The second insulating layer is filled in a side of the first display device layer away from the driving back plate;

[0013] The second trench structure penetrates through the second insulating layer, the second trench structure is filled with a metal material, and one end of the second trench structure is connected with the first trench structure.

[0014] In a possible implementation, the width of the second trench structure is smaller than the width of the first trench structure.

[0015] In a possible implementation, one end of the first trench structure is connected with a side of the light emitting unit away from the driving back plate, and the other end is connected with the upper surface of the driving back plate.

[0016] In a possible implementation, the side of the light emitting unit away from the driving back plate is an N-type ohmic contact layer, and one end of the first trench structure is connected with the N-type ohmic contact layer.

[0017] In a possible implementation, the N-type ohmic contact layer comprises a first part and a second part stacked in a direction away from the driving back plate, the surface size of the second part is greater than the surface size of the first part, and one end of the first trench structure is connected with the second part.

[0018] In a possible implementation, the second trench structure penetrates through the second part, so that the second trench structure is connected with the first trench structure.

[0019] In a possible implementation, the side of the light emitting unit close to the driving back plate is a P-type ohmic contact layer, the P-type ohmic contact layer is connected with a through hole, and the light emitting unit is connected with an anode contact in the driving back plate through the through hole filled with a metal material.

[0020] In a possible implementation, the first groove structure and the second groove structure corresponding to the adjacent light emitting units are in communication with each other.

[0021] Or,

[0022] The first groove structure and the second groove structure corresponding to the adjacent light emitting units are isolated from each other by an insulating medium.

[0023] In a possible implementation, the first groove structure and the second groove structure correspond to groove patterns in a top view, and the groove patterns comprise:

[0024] One of a circle, a rectangle, a hexagon, and an octagon.

[0025] In a possible implementation, the display module further comprises a microlens.

[0026] The microlens is disposed on the second insulating layer.

[0027] In a possible implementation, the metal material filled in the first groove structure and the second groove structure comprises:

[0028] Aluminum, nickel vanadium, and copper deposited vertically in sequence.

[0029] Or, deposited aluminum.

[0030] Or, deposited tungsten.

[0031] Compared with the prior art, the utility model has the following beneficial effects:

[0032] By etching groove structures in the display module of the micro display light emitting pixel and filling metal materials in the groove structures, better optical crosstalk isolation is achieved through the through groove structures, the light emitting angle can be constrained by the depth of the groove structures, and the design process of the groove structures is relatively mature, and the yield is guaranteed.

[0033] Further, the light emitting unit and the groove structure in the display module belong to an inorganic material system, have good temperature resistance and mechanical strength, and have guaranteed reliability.

[0034] Further, the back groove structure design idea, the back groove structure design idea, and the front-back groove structure combination design idea are provided, and different schemes can be freely selected according to needs. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of an optical crosstalk phenomenon corresponding to related technologies;

[0036] Figure 2 is a structural schematic diagram of a micro display light emitting pixel provided in the embodiment of the application;

[0037] Figure 3 is a circuit schematic diagram of a driving circuit provided in an embodiment of the present application;

[0038] Figure 4 is a schematic diagram of an optical crosstalk phenomenon corresponding to the embodiment of the present application;

[0039] Figure 5 is a structural schematic diagram of a micro-display light-emitting pixel with a microlens structure provided in an embodiment of the present application;

[0040] Figure 6 is a schematic diagram of a trench pattern provided in an embodiment of the present application;

[0041] Figure 7 is a method flowchart of a preparation method of a micro-display light-emitting pixel provided in an embodiment of the present application;

[0042] Figure 8 is a structural schematic diagram of a driving backplate provided in an embodiment of the present application;

[0043] Figure 9 is a structural schematic diagram of an inorganic compound semiconductor provided in an embodiment of the present application;

[0044] Figure 10 is a structural schematic diagram of an inorganic compound semiconductor after step etching provided in an embodiment of the present application;

[0045] Figure 11 is a structural schematic diagram of an inorganic compound semiconductor after trench structure preparation provided in an embodiment of the present application;

[0046] Figure 12 is a structural schematic diagram of an inorganic compound semiconductor after metal filling provided in an embodiment of the present application;

[0047] Figure 13 is a structural schematic diagram of an inorganic compound semiconductor combined with a driving backplate provided in an embodiment of the present application;

[0048] Figure 14 is a structural schematic diagram of an inorganic compound semiconductor after step etching provided in an embodiment of the present application.

[0049] Reference signs:

[0050] 10 - drive backplane, 11 - anode contact, 21 - first display device layer, 22 - second display device layer, 30 - light emitting unit, 311 - P-type ohmic contact layer, 312 - via, 313 - N-type ohmic contact layer, 314 - first portion, 315 - second portion, 316 - substrate, 317 - active quantum well layer, 41 - first trench structure, 42 - second trench structure, 50 - microlens, 61 - first insulating layer, 62 - second insulating layer. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0052] In the description of the present application, it should be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0053] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] The conventional anti-crosstalk design scheme of micro-display light emitting pixels has many defects, such as:

[0055] For the anti-crosstalk design scheme of preparing microlenses, the microlenses prepared by the scheme belong to an organic material system, which has insufficient temperature resistance, mechanical strength, and reliability defects, and cannot achieve complete optical isolation between pixels. When the pixel size continues to be miniaturized, when the light-emitting angle is ±55°, the problem of adjacent pixel crosstalk before entering the microlenses occurs. Figure 1 As an example, taking a 4um pixel size and a 2um light-emitting unit GaN Micro LED vertical structure device as an example, the vertical structure has the smallest light-emitting angle ±55° of a conventional LED device, which is lower than the light-emitting angle ±60-70° of a horizontal structure and a flip-chip structure LED device. When the light-emitting angle is ±55°, the optical crosstalk between adjacent pixels cannot be completely isolated because the light emitted by the active light-emitting area will pass through the entire light-emitting unit and become a multi-faceted out-of-angle. The actual light angle will be smaller than the design value, and the light-emitting angle will be ±50°. Figure 1 More complex, because the light is refracted and reflected multiple times in the light-emitting unit, the optical crosstalk between pixels will be more serious.

[0056] For the anti-crosstalk design scheme using a black matrix, the black matrix is used to block light by the light absorption characteristics of the black matrix material to achieve optical crosstalk isolation between pixels. The black matrix is an organic material system, which has insufficient temperature resistance, mechanical strength, and reliability defects, and the black matrix absorbs light, which will cause overall brightness loss. In some schemes, a trapezoidal structure similar to the black matrix is formed by metal patterning deposition to avoid reliability problems. However, neither the black matrix nor the metal patterning deposition scheme can adapt to very small pixel sizes, such as when the pixel size is reduced to less than 5um, the resolution of the black matrix and the photoresist mask peeling problem of the metal patterning deposition scheme will bring challenges to yield and mass production capacity.

[0057] In order to avoid the above problems, in the embodiments of the present application, a technical scheme is proposed for light emission constraint by a through-type groove structure to achieve better optical crosstalk isolation.

[0058] First, the specific structure of the micro display light-emitting pixel proposed in the present application is described.

[0059] The present application provides a micro display light-emitting pixel (hereinafter referred to as a micro display light-emitting pixel) for anti-crosstalk, as shown in Figure 2 The micro display light-emitting pixel includes:

[0060] The system includes a driving backplate 10 and a display module disposed on the driving backplate 10. The display module includes a first display device layer 21 and a second display device layer 22 disposed on the first display device layer 21. The first display device layer 21 includes a light-emitting unit 30, a first insulating layer 61, and a first trench structure 41. The second display device layer 22 includes a second insulating layer 62 and a second trench structure 42. The first insulating layer 61 is formed outside the light-emitting unit 30. The first trench structure 41 extends through the first insulating layer 61 and surrounds the light-emitting unit 30. The first trench structure 41 is filled with a metallic material. The light-emitting unit 30 is an inorganic compound semiconductor. The second insulating layer 62 is formed on the side of the first display device layer 21 away from the driving backplate 10. The second trench structure 42 extends through the second insulating layer 62. The second trench structure 42 is filled with a metallic material, and one end of the second trench structure 42 is connected to the first trench structure 41.

[0061] The driving backplane 10 is an active driving backplane that combines one or more of the following: thin-film transistor (TFT), low-temperature polysilicon (LTPS), CMOS integrated circuit, and high-mobility transistor (HEMT). Specifically, the driving backplane 10 is provided with a driving circuit, which has at least one anode. An exemplary circuit structure of the driving circuit is as follows: Figure 3 As shown. It should be noted that the driving circuit in this embodiment is an active drive, and the circuit diagram shown in this embodiment is only a simplified schematic diagram. The driving circuit may include active, passive, or semi-passive control circuits. All anodes included in the driving circuit can be linearly arranged or arrayed, and any anode may be located in the middle or at the edge of the driving backplate 10. This embodiment does not impose any restrictions on this.

[0062] The display module incorporates a through-type first trench structure 41 and a second trench structure 42. The first trench structure 41 surrounds the light-emitting unit 30 within the display module and is filled with a metallic material. The second trench structure 42 sits atop the first trench structure 41 and is also filled with a metallic material. The light-emitting unit 30 is an inorganic compound semiconductor, resulting in a purely inorganic structure with high reliability. For example,... Figure 4 As shown, the design of the trench structure 40 (i.e., the TI structure in the figure) can constrain the emission angle, thereby preventing optical crosstalk between adjacent microdisplay emission pixels.

[0063] Furthermore, such as Figure 5As shown, the display module further comprises: a microlens 50; the microlens 50 is arranged on the second insulating layer 62. The top of the display module can be provided with a microlens 50, which first passes through the first groove structure 41 and the second groove structure 42 to constrain the basic light emission, and then uses the microlens 50 to further isolate the optical crosstalk of the light emitted by the light emitting unit 30. The material of the microlens 50 can be a compound semiconductor, and can be a dielectric material such as silicon oxide and silicon nitride deposited subsequently.

[0064] Further, the light emitting unit 30 in the display module is an inorganic compound semiconductor, which is usually a wafer or a region of appropriate size cut from the wafer. Taking the wafer as an example, the wafer refers to a compound formed by two or more elements with a certain atomic ratio, and has certain semiconductor properties such as a certain band gap and energy band structure. Specifically, it can be a crystalline inorganic compound (such as a III-V group or II-VI group compound semiconductor), and then a layer for electrical contact is prepared on the surface of the compound, and the compound can be arbitrarily combined during subsequent stacking. In this embodiment, the light emitting unit 30 involves ultraviolet light, green light, blue light AlGaN, InGaN ternary material system, and its substrate material can be GaN, Si, SiC, sapphire, etc., and long-wave such as red light and infrared. The red light can be a ternary InGaN material system or a quaternary AlGaInP red light compound LED epitaxial on a GaAs substrate, and the infrared mainly includes InP, GaAs, AlGaAs, etc. In addition, this embodiment does not limit the corresponding shape of the light emitting unit 30 from the top, which can be circular or other polygons such as rectangular, hexagonal, octagonal, etc.

[0065] In an embodiment, when the light emitting unit 30 includes a red light compound epitaxial, the red light compound epitaxial can be a quaternary AlGaInP or a ternary InGaN material, which can be based on a GaAs, Si, sapphire, Ga2O3, etc. substrate. The following Table 1 is a brief structure example, in which P-GaAs can be replaced by P-GaP and P-AlGaAs:

[0066] Table 1

[0067] Layer Name Material Layer Name Material P-type Ohmic Contact Layer P-GaAs P-type Ohmic Contact Layer P-GaN Active Quantum Well Layer AIGaInP Active Quantum Well Layer InGaN & GaN N-type Ohmic Contact Layer N-GaAs N-type Ohmic Contact Layer N-GaN Etch Stop Layer N-AIGaInP Etch Stop Layer AIN & GaN Substrate N-GaAs Substrate Si

[0068] In an embodiment, when the light emitting unit 30 includes a blue light and green light compound semiconductor, the blue light and green light compound semiconductor is a ternary InGaN compound, which can be based on a Si, sapphire, Ga2O3, etc. substrate. The structure example is as follows Table 2:

[0069] Table 2

[0070] Layer Name Material Layer Name Material P-type Ohmic Contact Layer P-GaN P-type Ohmic Contact Layer P-GaN Active Quantum Well Layer InGaN & GaN Active Quantum Well Layer InGaN & GaN N-type Ohmic Contact Layer N-GaN N-type Ohmic Contact Layer N-GaN Etch Stop Layer InGaN Etch Stop Layer AIN & GaN Substrate GaN Substrate Si

[0071] In an embodiment, when the light emitting unit 30 comprises a UV compound semiconductor, the UV compound semiconductor is an AlGaN ternary compound, which can be based on Si, Sapphire, SiC, etc. substrates, and the structure thereof is shown in Table 3 below:

[0072] Table 3

[0073] Layer Name Material Layer Name Material P-type Ohmic Contact Layer P-GaN P-type Ohmic Contact Layer P-GaN Active Quantum Well Layer AIGaN & InGaN Active Quantum Well Layer AIGaN & InGaN N-type Ohmic Contact Layer N-GaN N-type Ohmic Contact Layer N-GaN Buffer Layer AIN & AIGaN Buffer Layer AIN & GaN Substrate Si Substrate Sapphire

[0074] In an embodiment, when the light emitting unit 30 comprises an infrared compound semiconductor, the infrared compound semiconductor is an AlGaAs ternary compound, which can be based on GaAs, InP, etc. substrates, and the structure thereof is shown in Table 4 below:

[0075] Table 4

[0076]

[0077]

[0078] As shown in Tables 1 to 4 above, by selecting different compound materials to prepare the device, light emitting components of different wavelengths can be obtained, and according to different compound characteristics, different materials can be selected as P-type and N-type ohmic contact layer materials. For example, the P-type ohmic contact layer can be an ITO transparent conductive film, and the N-type ohmic contact layer can be a metal In+ITO transparent conductive film, which can be used as a general ohmic contact material. In particular, the P-type ohmic contact layer of GaN can be a single layer or a stack of Ni, Au, Ag, Al, etc. metals, and the N-type ohmic contact layer can be a single layer or a stack of Ti, Cr, Ni, Al, etc. metals. The P-type ohmic contact layer of GaAs can be a single layer, an alloy or a stack of Au, Be, Zn, etc. metals, and the N-type ohmic contact layer can be a single layer, an alloy or a stack of Au, Ge, Ni, Pt, In, etc. metals.

[0079] Further, the metal material filled in the first trench structure 41 and the second trench structure 42 comprises: aluminum (Al), nickel vanadium (NiV), and copper (Cu) deposited vertically in sequence; or aluminum deposited; or tungsten (W) deposited. In the above trench structure, the metal material filled therein can be seed layer Al, NiV deposited by plasma vapor deposition, followed by Cu electroplating, wherein Al can be used as a reflective metal to improve brightness, and Al can also be used as the N-type ohmic contact metal of the N-type ohmic contact layer to realize N connection. NiV is used as an adhesion layer and a barrier layer to adhere Al and Cu and to block the migration of Al, and Cu is used for electroplating. Further, NiV can be replaced by any one of Ni, Ti, and TiN; the metal material can also be a metal such as Al or W deposited by plasma vapor deposition at room temperature or thermal deposition. Further, TIN metal deposition can be performed before Al or W deposition.

[0080] Furthermore, the groove patterns corresponding to the first groove structure 41 and the second groove structure 42 when viewed from above include one of the following: circle, rectangle, hexagon, and octagon. When viewed from above, the groove pattern surrounding the light-emitting unit 30 can be circle, rectangle, hexagon, octagon, etc., and this embodiment does not impose any restrictions on this.

[0081] Furthermore, the first trench structure 41 and the second trench structure 42 corresponding to adjacent light-emitting units 30 are interconnected; or, the first trench structure 41 and the second trench structure 42 corresponding to adjacent light-emitting units 30 are isolated from each other by an insulating medium. The above trench structure can achieve the following: Figure 6 The style shown between connected pixels can also achieve the following: Figure 6 The style inside the pixel shown. Figure 6 The following is an example illustration using only circular and rectangular groove shapes.

[0082] Among them, the micro-display light-emitting pixels adopt a front and back trench structure combined design concept. In the corresponding fabrication process of this structure design, the front trench structure design concept is first adopted to fabricate a first trench structure 41 in a display device layer in the display module. Then, the display module is combined with the driving backplate 10. Subsequently, the back trench structure design concept is further adopted. For the combined device, another display device layer is added in the display module to fabricate another second trench structure 42.

[0083] The first insulating layer 61 and the second insulating layer 62 can be single layers or stacked layers of dielectric layers such as silicon oxide, silicon nitride, SiC, SICN, Ti3O5, and Ni2O5. The thickness of the second insulating layer 62 and the depth of the second trench structure 42 are not related to the thickness of the light-emitting unit 30, and the depth of the second trench structure 42 can be freely set.

[0084] Furthermore, the width of the second trench structure 42 is smaller than the width of the first trench structure 41. On the one hand, this allows for the retention of photolithographic alignment deviations and reduces process difficulty; on the other hand, it ensures that the first trench structure 41 is connected to the N-type ohmic contact layer 313 to achieve cathode connectivity. Typically, the second trench structure 42 on the back side has 50% of the size of the first trench structure 41 on the front side.

[0085] Furthermore, one end of the first groove structure 41 is connected to the side of the light-emitting unit 30 away from the driving back plate 10, and the other end is connected to the upper surface of the driving back plate 10.

[0086] Among them, the side of the light-emitting unit 31 away from the driving back plate 10 is an N-type ohmic contact layer 313, and one end of the first trench structure 41 is connected to the N-type ohmic contact layer 313.

[0087] Further, the N-type ohmic contact layer 313 includes a first portion 314 and a second portion 315 stacked in a direction away from the driving backplane 10, a surface size of the second portion 315 is greater than a surface size of the first portion 314, and one end of the first trench structure 41 is connected to the second portion 315. The cathode electrical structure is prepared by thinning the second portion 315.

[0088] Further, the second trench structure 42 penetrates the second portion 315, so that the second trench structure 42 is connected to the first trench structure 41. The second trench structure 42 is connected to the first trench structure 41, so that the overall coherent trench structure is realized to better constrain the light.

[0089] Further, the light emitting unit 30 has a P-type ohmic contact layer 311 on a side close to the driving backplane 10, the P-type ohmic contact layer 311 is connected to a through hole 312, and the light emitting unit 30 is connected to the anode contact in the driving backplane 10 through the through hole 312 filled with a metal material. The surface of the P-type ohmic contact layer 311 of the light emitting unit 30 is prepared with the through hole 312, and the through hole 312 can be connected to the middle region of the surface of the P-type ohmic contact layer 311. The metal material filled in the through hole 312 can be the same as or different from the metal material filled in the first trench structure 41 and the second trench structure 42, such as the same deposited Al, NiV, and Cu.

[0090] In summary, the micro display light emitting pixel provided by the embodiment of the present application can better isolate optical crosstalk by etching a trench structure in the display module of the micro display light emitting pixel and filling the trench structure with a metal material, and can customize the constraint light emitting angle through the depth of the trench structure. The design process of the trench structure is relatively mature, and the yield is guaranteed.

[0091] Further, the light emitting unit and the trench structure in the display module belong to an inorganic material system, which has good temperature resistance, mechanical strength, and reliability.

[0092] Further, the back trench structure design idea, the back trench structure design idea, and the front and back trench structure combination design idea are provided, and different schemes can be freely selected according to needs.

[0093] Next, the preparation method of the micro display light emitting pixel described in the above embodiment will be described. The method is used to prepare the micro display light emitting pixel described in the above embodiment, as shown in FIG. 1, and can include the following steps: Figure 7

[0094] S1: preparing a driving backplane.

[0095] Exemplarily, the cross-sectional structure of the driving backplane single pixel is as shown in FIG. 2.​Figure 8 As shown, the driving backplate 10 includes a through anode contact 11, and an insulating medium is arranged around the anode contact 11.

[0096] S2: a display module is prepared on the driving backplate, the display module includes a light emitting unit and a trench structure, the light emitting unit is in conduction with the anode contact in the driving backplate, the trench structure surrounds the light emitting unit and penetrates the vertical area where the display module is located, the trench structure is filled with a metal material, and the light emitting unit is an inorganic compound semiconductor.

[0097] For example, the cross-sectional structure of the inorganic compound semiconductor is as shown in Figure 9 As shown, the inorganic compound semiconductor includes at least the following layers stacked from bottom to top: a substrate 316, an N-type ohmic contact layer 313, an active quantum well layer 317, and a P-type ohmic contact layer 311.

[0098] In a possible implementation, after S2, the following step is further included: a microlens is prepared on the light emitting unit and the trench structure. The microlens can be prepared by etching, and the microlens material can be a compound semiconductor or a dielectric material such as silicon oxide and silicon nitride deposited subsequently.

[0099] For the front and back trench structure combination design idea in the above embodiment, S2 can specifically include the following steps:

[0100] S211: step etching is performed on the inorganic compound semiconductor to prepare a first light emitting unit.

[0101] Specifically, as shown in Figure 10 The inorganic compound semiconductor is step etched using a patterned etching scheme such as plasma dry etching, and the etching is performed to the N-type ohmic contact layer 313 to prepare the light emitting unit 30.

[0102] S212: the light emitting unit is step filled with an insulating material to form a first insulating layer.

[0103] Specifically, the light emitting unit is step filled to form the first insulating layer using a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, and Ni2O5.

[0104] S213: the first insulating layer is etched to form a through hole connected with the P-type ohmic contact layer in the light emitting unit and a first trench structure surrounding the light emitting unit.

[0105] Specifically, as shown in Figure 11As shown, the first insulating layer 61 is etched using patterned etching methods such as plasma dry etching to realize the via area of ​​the P-type ohmic contact layer 311 and the trench isolation around the light-emitting unit 30.

[0106] S214: The through hole and the first trench structure are filled with metal material, and the light-emitting unit, the first insulating layer, and the first trench structure are combined to form the first display device layer.

[0107] Specifically, such as Figure 12 As shown, the through-hole 312 and the first trench structure 41 are filled with metal material through a metal backfill process. For example, Al, NiV, and Cu are deposited sequentially in the through-hole 312 and the first trench structure 41; or Al is deposited in the through-hole 312 and the first trench structure 41; or W is deposited in the through-hole 312 and the first trench structure 41. Furthermore, after filling, chemical mechanical planarization (CMP) can be used to remove excess metal and planarize the surface of the filled metal material.

[0108] S215: The first display device layer is bonded to the driving backplane through a hybrid bonding process. During bonding, the light-emitting unit is connected to the anode contact in the driving backplane through a through hole filled with metal material.

[0109] like Figure 13 As shown, when combined, the through hole 312 in the first display device layer 21 is connected to the anode contact 11 of the drive back plate 10, and the cathode of the first display device layer 21 is connected to the common cathode of the drive back plate through the first trench structure 41.

[0110] In one possible implementation, after S215, the following steps are also included: removing the compound substrate from the light-emitting unit; and roughening the surface of the first light-emitting unit after removing the substrate.

[0111] The compound substrate of the combined light-emitting unit is removed. By removing the substrate and thinning the compound, N-contact conduction is achieved while the cathode is thinned, reducing optical crosstalk between pixels. Furthermore, the surface of the light-emitting unit after substrate removal is roughened to enhance light extraction efficiency.

[0112] It is understandable that in steps S211 to S215 above, subsequent fabrication is based on step etching to the N-type ohmic contact layer. In another design, this step etching can be as follows: Figure 14 The inorganic compound semiconductor, except for the substrate 316, is completely etched through. Correspondingly, a process step is added to extend the N-type ohmic contact layer and connect it to the first trench structure, so as to connect the cathode of the first display device layer to the common cathode of the drive backplane through the first trench structure.

[0113] S216: filling the first display device layer with an insulating material to form a second insulating layer.

[0114] Specifically, the first display device layer is filled with a single layer or a stack of layers of a medium layer such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. to form the second insulating layer.

[0115] S217: etching the second insulating layer to form a second trench structure connected to the first trench structure at one end.

[0116] Specifically, the second insulating layer is etched using a patterned etching scheme such as plasma dry etching to achieve trench isolation around the light emitting unit in the second insulating layer, which is the second trench structure.

[0117] S218: filling the second trench structure with a metal material, and the second insulating layer and the second trench structure combined to form a second display device layer.

[0118] Specifically, the second trench structure is filled with a metal material through a metal backfilling process, such as depositing metal Al, NiV, and Cu in the second trench structure in sequence, or depositing metal Al in the second trench structure, or depositing metal W in the second trench structure. Further, after filling is completed, CMP can be used to remove excess metal on the surface of the filled metal material and perform planarization treatment.

[0119] It can be understood that if the above front and back trench structure combination design idea is adopted, the advantage is that N-type ohmic contact can be directly formed with the first light emitting unit, and the depth of the second trench structure can be very flexibly customized on the back surface.

[0120] In summary, the preparation method of the micro display light emitting pixel provided by the embodiments of the present application etches a trench structure in the display module of the micro display light emitting pixel and fills the trench structure with a metal material. Through the through-type trench structure, better optical crosstalk isolation is achieved, the light emitting angle can be constrained by the depth of the trench structure, and the design process of the trench structure is relatively mature, and the yield is guaranteed.

[0121] Further, the preparation method uses a semiconductor process, which can be compatible to nanoscale work, and is more suitable for the preparation of micro pixel size.

[0122] All the optional technical solutions described above can be combined to form optional embodiments of the present application, that is, any number of embodiments can be combined to meet the needs of different application scenarios, which are all within the protection scope of the present application and will not be described one by one here.

[0123] It should be noted that the above only the preferred embodiments of the present application, and not to limit the present application, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included in the scope of protection of the present application.

Claims

1. A microdisplay light emitting pixel that is immune to cross-talk, characterized by, The micro display light emitting pixel comprises a driving backboard and a display module arranged on the driving backboard. The display module comprises a first display device layer and a second display device layer arranged on the first display device layer. The first display device layer comprises a light emitting unit, a first insulating layer and a first trench structure. The second display device layer comprises a second insulating layer and a second trench structure. The first insulating layer is filled in the outside of the light emitting unit. The first trench structure penetrates through the first insulating layer and surrounds the light emitting unit. The first trench structure is filled with a metal material. The light emitting unit is an inorganic compound semiconductor. The second insulating layer is filled on the side of the first display device layer away from the driving backboard. The second trench structure penetrates through the second insulating layer. The second trench structure is filled with a metal material. One end of the second trench structure is connected with the first trench structure.

2. The micro display light emitting pixel of claim 1, wherein a width of the second trench structure is smaller than a width of the first trench structure.

3. The micro display light emitting pixel of claim 1, wherein one end of the first trench structure is connected with a side of the light emitting unit away from the driving backboard, and the other end is connected with an upper surface of the driving backboard.

4. The micro display light emitting pixel of claim 3, wherein the side of the light emitting unit away from the driving backboard is an N-type ohmic contact layer, and one end of the first trench structure is connected with the N-type ohmic contact layer.

5. The micro display light emitting pixel of claim 4, wherein the N-type ohmic contact layer comprises a first part and a second part stacked in a direction away from the driving backboard.

6. The micro display light emitting pixel of claim 5, wherein the second trench structure penetrates through the second part, so that the second trench structure is connected with the first trench structure.

7. The micro display light emitting pixel of claim 1, wherein a side of the light emitting unit close to the driving backboard is a P-type ohmic contact layer.

8. The micro display light emitting pixel of claim 1, wherein the first trench structure and the second trench structure corresponding to adjacent light emitting units are connected with each other.

9. The micro display light emitting pixel of claim 1, wherein the first trench structure and the second trench structure corresponding to adjacent light emitting units are isolated from each other by an insulating medium.

10. The micro display light emitting pixel of claim 1, wherein the first trench structure and the second trench structure correspond to a trench pattern in a top view, and the trench pattern comprises one of a circle, a rectangle, a hexagon and an octagon.

11. The micro display light emitting pixel of claim 1, wherein the display module further comprises a microlens.

9. The microdisplay light emitting pixel of claim 1, wherein, 12. The micro display light emitting pixel of claim 11, wherein the microlens is arranged on the second insulating layer.

13. The micro display light emitting pixel of claim 1, wherein the metal material filled in the first trench structure and the second trench structure comprises one of gold, silver, copper and aluminum.

10. The microdisplay light emitting pixel of claim 1, wherein, ​ ​ 11. The microdisplay light emitting pixel of claim 1, wherein, ​ Aluminum, nickel vanadium, copper deposited vertically in sequence; Or, aluminum deposited; Or, tungsten deposited.

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