A full-color MicroLED and its preparation method

Abstract

The present invention relates to the technical field of display chips, and discloses a full-color MicroLED and a preparation method thereof. The full-color MicroLED comprises a driving substrate, a first light-emitting layer, a first connection layer, a second light-emitting layer, and a second connection layer. The driving substrate comprises a first P-type semiconductor electrode transition layer, the first light-emitting layer comprises a first light-emitting unit, a second P-type semiconductor electrode transition layer, the first connection layer comprises a first N-type semiconductor electrode transition layer, a first N-electrode grid, and a third P-type semiconductor electrode transition layer. The second light-emitting layer comprises a second light-emitting unit, a fourth P-type semiconductor electrode transition layer, the second connection layer comprises a second N-type semiconductor electrode transition layer, and a second N-electrode grid. A color conversion layer is provided at a portion of the second light-emitting unit corresponding to the second light-emitting unit on the second connection layer. The present invention drives the light-emitting units on the first light-emitting layer and the second light-emitting layer to emit green light and blue light respectively through the driving substrate, and then converts part of the blue light of the second light-emitting unit into red light through the color conversion layer, thereby achieving full-color luminescence.

Description

Technical Field

[0001] The present invention belongs to the technical field of display chips, and specifically relates to a full-color MicroLED and a preparation method thereof. Background Art

[0002] The full name of Micro LED is Micro Light Emitting Diode, which is also called micro-light-emitting diode in Chinese. It can also be written as μLED. It generally refers to the technology of using LED light-emitting units with a size of 1~60μm to form a display array. Its size is equivalent to 1 / 10 of a human hair. It has the characteristics of no need for backlight, high photoelectric conversion efficiency, and response time at the ns level. It is a technology that makes LED thin-film, miniaturized and arrayed, so that its volume is only 1% of the size of mainstream LEDs, and the pixel distance is from millimeters to microns. As an emerging display technology, MicroLED has the advantages of high resolution, low power consumption, high brightness and fast response time. Therefore, it has important application value in the fields of high-resolution display, wearable devices, augmented reality and high-speed visible light communication. In particular, full-color display MicroLED can realize red, green and blue light emission, so it has greater advantages in the field of full-color display with higher requirements for pixel size and pixel spacing.

[0003] Currently, MicroLED needs to achieve full color, but there is no reliable full color technology. Mass transfer technology and quantum dot color conversion technology can be called the fastest growing full color technologies. However, mass transfer technology and quantum dot color conversion technology have their own defects: 1. Mass transfer technology is to make the light-emitting unit independent, while a single light-emitting unit of MicroLED is only 2-20μm. There are hundreds of thousands to millions of light-emitting units on a chip, and hundreds of millions to billions of light-emitting units on a wafer. If all of them are cut off, it will take a long time, and the minimum cutting path can only be 25-35μm. It is easy to damage the light-emitting unit during cutting, which reduces the yield; 2. Quantum dot color conversion technology adds quantum dots to the light-emitting pixels, but the luminous efficiency of color conversion technology is low. Summary of the invention

[0004] In order to solve the deficiencies mentioned in the above-mentioned background technology, the purpose of the present invention is to provide a full-color MicroLED and a preparation method thereof. The light-emitting units on the first light-emitting layer and the second light-emitting layer of the present invention are respectively connected to the electrodes on the driving substrate through the N-type semiconductor electrode transition layer, and the light-emitting units on the first light-emitting layer and the second light-emitting layer are driven by the driving substrate to emit green light and blue light respectively. A color conversion layer is provided at the second light-emitting unit corresponding to the part of the second connecting layer, and part of the blue light is converted into red light through the color conversion layer to achieve full-color luminescence.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A full-color MicroLED includes a driving substrate, a first insulating isolation layer is deposited on the driving substrate, and a first P-type semiconductor electrode transition layer is provided at the first insulating isolation layer corresponding to the driving substrate electrode;

[0007] A first light-emitting layer includes a second insulating isolation layer, a plurality of first light-emitting units arranged in an array are arranged on the second insulating isolation layer, a second P-type semiconductor electrode transition layer is arranged at the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer includes a short P-type semiconductor electrode transition layer and a long P-type semiconductor electrode transition layer, the bottom of the first light-emitting unit is connected to the first P-type semiconductor electrode transition layer through the short P-type semiconductor electrode transition layer, and the long P-type semiconductor electrode transition layer runs through the second insulating isolation layer;

[0008] The first connection layer includes a first N-type semiconductor electrode transition layer, the bottom of the first N-type semiconductor electrode transition layer is connected to the first light-emitting layer, a window is opened in the first N-type semiconductor electrode transition layer corresponding to the long P-type semiconductor electrode transition layer, a first N-electrode grid is provided on the surface of the first N-type semiconductor electrode transition layer away from the driving substrate, a third insulating isolation layer is deposited above the first N-type semiconductor electrode transition layer, and a third P-type semiconductor electrode transition layer is provided through the third insulating isolation layer corresponding to the long P-type semiconductor electrode transition layer;

[0009] The second light-emitting layer includes a fourth insulating isolation layer, a plurality of second light-emitting units arranged in an array are arranged on the fourth insulating isolation layer, a fourth P-type semiconductor electrode transition layer is arranged at a position of the fourth insulating isolation layer corresponding to the third P-type semiconductor electrode transition layer, and the bottom of the second light-emitting unit is connected to the third P-type semiconductor electrode transition layer through the fourth P-type semiconductor electrode transition layer;

[0010] The second connection layer includes a second N-type semiconductor electrode transition layer, the bottom of the second N-type semiconductor electrode transition layer is connected to the second light-emitting layer, the surface of the second N-type semiconductor electrode transition layer is provided with a second N-electrode grid, a fifth insulating isolation layer is deposited above the second N-type semiconductor electrode transition layer, a window is opened at a portion of the fifth insulating isolation layer corresponding to the second light-emitting unit, and a color conversion material is filled in the window of the fifth insulating isolation layer to form a color conversion layer.

[0011] Further preferably, the driving substrate is a silicon-based CMOS backplane.

[0012] Further preferably, the first insulating isolation layer, the second insulating isolation layer, the third insulating isolation layer, the fourth insulating isolation layer and the fifth insulating isolation layer are made of SiO2, Al2O3 or Si3N4 materials.

[0013] Further preferably, the first light-emitting unit includes a first epitaxial layer, a first P-electrode layer is provided at the bottom of the first epitaxial layer, a first passivation layer and a first reflective layer are provided on the sidewalls of the first epitaxial layer in sequence, and the second light-emitting unit has the same structure as the first light-emitting unit.

[0014] Further preferably, the epitaxial layer of the first light-emitting unit is a semiconductor material that excites green light, and the epitaxial layer of the second light-emitting unit is a semiconductor material that excites blue light.

[0015] Further preferably, the projections of the first light-emitting unit, the second light-emitting unit and the color conversion layer on the top surface may be in the shape of a triangle, a circle or a polygon.

[0016] Further preferably, the first P-electrode layer is an ITO thin film.

[0017] Further preferably, the first passivation layer is made of SiO2, Al2O3 or Si3N4 material.

[0018] Further preferably, the first light reflecting layer is a Ti / Al / TiN, Ti / Al / Ag, Ti / A1 / ITO or Ti / Al / SiO2 structure.

[0019] Further preferably, the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer, the third P-type semiconductor electrode transition layer, and the fourth P-type semiconductor electrode transition layer are made of metal materials, and the metal materials are Cu, Al, Sn, Au, Pt, Ti or Cr.

[0020] Further preferably, the first N-type semiconductor electrode transition layer and the second N-type semiconductor electrode transition layer are ITO films.

[0021] Further preferably, the first N-electrode grid and the second N-electrode grid are made of Cr / Pt / Au or Cr / Al / Au / Cu / Ti materials.

[0022] Further preferably, the color conversion material is a quantum dot material, the quantum dot material is a red quantum dot material, and a third light reflecting layer is disposed on the side wall of the color conversion layer.

[0023] Further preferably, an encapsulation layer is further provided on the surface of the second connection layer, and a lens structure is provided on the surface of the encapsulation layer. The lens structure corresponds to a single pixel or a single RGB unit. The single RGB unit includes at least one R, G and B pixel.

[0024] A method for preparing a full-color MicroLED comprises the following steps:

[0025] S1, depositing a layer of SiO2 on the surface of the driving substrate to form a first insulating isolation layer, then opening windows at the corresponding electrodes of the first insulating isolation layer by photolithography-etching, electroplating metal on the surface of the first insulating isolation layer and then chemically mechanically polishing and flattening it to form a first P-type semiconductor electrode transition layer;

[0026] S2, processing the first epitaxial wafer, forming a first light-emitting unit at a corresponding position according to the chip design, then depositing a layer of SiO2 on the light-emitting unit to form a second insulating isolation layer, and then opening a window in the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer by photolithography-etching, electroplating the surface of the second insulating isolation layer with metal, and then chemically and mechanically polishing and flattening it to form a second P-type semiconductor electrode transition layer;

[0027] S3, performing surface activation and pre-alignment on the first epitaxial wafer of step S2 and the chip of step S1, then bonding the first epitaxial wafer and the chip by hybrid bonding, and finally removing the substrate of the first epitaxial wafer;

[0028] S4, sputtering an ITO film on the surface of the first epitaxial wafer to form a first N-type semiconductor electrode transition layer, then plating a first N-electrode grid on the surface of the first N-type semiconductor electrode transition layer away from the driving substrate through a photolithography-lift off process, opening a window in the first N-type semiconductor electrode transition layer corresponding to the long P-type semiconductor electrode transition layer, then depositing a layer of SiO2 on the first N-type semiconductor electrode transition layer to form a third insulating isolation layer, then opening a window in the third insulating layer corresponding to the long P-type semiconductor electrode transition layer through a photolithography-etching method, finally electroplating metal on the surface of the third insulating isolation layer and then chemically mechanically polishing and flattening it to form a third P-type semiconductor electrode transition layer, thereby completing the preparation of the first connection layer;

[0029] S5, processing the second epitaxial wafer in the same manner as in step S2, completing the preparation of the second light-emitting unit of the second light-emitting layer, the fourth insulating isolation layer and the fourth P-type semiconductor electrode transition layer;

[0030] S6, performing surface activation and pre-alignment on the second epitaxial wafer of step S5 and the chip of step S4, then bonding the second epitaxial wafer and the chip by hybrid bonding, and finally removing the substrate of the second epitaxial wafer;

[0031] S7, sputtering an ITO film on the surface of the second epitaxial wafer to form a second N-type semiconductor electrode transition layer, then plating a second N-electrode grid on the surface of the second N-type semiconductor electrode transition layer by a photolithography-lift-off process, and finally depositing a layer of SiO2 on the second N-type semiconductor electrode transition layer to form a fifth insulating isolation layer, thereby completing the preparation of the second connection layer;

[0032] S8. According to the chip design, a window is opened at the second light-emitting unit corresponding to the fifth insulating isolation layer by photolithography-etching, a composite metal layer is plated on the surface of the fifth insulating isolation layer, and then the composite metal layer in excess is removed by photolithography-etching, leaving only the inner wall of the window of the fifth insulating isolation layer to form a third reflective layer, and finally quantum dot material is filled by photolithography to form a color conversion layer.

[0033] Further preferably, the processing of the first epitaxial wafer in step S2 specifically includes the following steps:

[0034] S201, sputtering an ITO film on the surface of the first epitaxial layer of the first epitaxial wafer, and then etching the ITO film by photolithography-etching to form a first P-electrode layer;

[0035] S202, continue etching the first epitaxial layer by photolithography-etching to pattern it, and form a first light-emitting unit;

[0036] S203, depositing a layer of SiO2 on the surface of the first epitaxial wafer to form a first passivation layer, then plating a composite metal layer on the surface of the first passivation layer to form a first reflective layer, and removing the first passivation layer and the first reflective layer on the top of the first reflective unit by photolithography and etching to expose the first P electrode layer on the top of the first light-emitting unit;

[0037] S204, depositing a layer of SiO2 above the light-emitting unit to form a second insulating isolation layer, and then opening a window in the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer by photolithography-etching;

[0038] S205, electroplating metal on the surface of the second insulating isolation layer and then performing chemical mechanical polishing to flatten it, forming a second P-type semiconductor electrode transition layer, and completing the processing of the first epitaxial wafer.

[0039] Further preferably, the overall processing steps of the second epitaxial wafer in step S5 are the same as those of the first epitaxial wafer, except that in step S204, a window is opened in the fourth insulating isolation layer corresponding to the third P-type semiconductor electrode transition layer.

[0040] Further preferably, the line widths of the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer and the third P-type semiconductor electrode transition layer are 1-2 μm.

[0041] Further preferably, the bonding accuracy of the first epitaxial wafer in step S3 and the second epitaxial wafer in step S6 are both less than or equal to 0.5 μm.

[0042] Beneficial effects of the present invention:

[0043] The light-emitting units on the first light-emitting layer and the second light-emitting layer of the present invention are respectively connected to the electrodes on the driving substrate through the N-type semiconductor electrode transition layer. The light-emitting units on the first light-emitting layer and the second light-emitting layer are driven by the driving substrate to emit green light and blue light respectively. A color conversion layer is provided at the second light-emitting unit corresponding to the second connection layer. The color conversion layer converts part of the blue light into red light to achieve full-color light emission. The present invention breaks the conventional MicroLED pixel arrangement method and adopts hybrid bonding technology. SiO2 plays a supporting role, the P-type semiconductor electrode transition layer is conductive, and one driving substrate is bonded to two epitaxial wafers to achieve simultaneous driving of the G / B epitaxial structure. At the same time, the quantum dot color conversion is superimposed, making color MicroLED easier to achieve, and the pixel arrangement makes the RGB color ratio more operational and selective. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 is a schematic diagram of the structure of the full-color MicroLED of the present invention;

[0046] Figure 2 is a schematic diagram of the pixel arrangement of the full-color MicroLED of the present invention;

[0047] Figure 3 is a schematic structural diagram of another embodiment of the full-color MicroLED of the present invention;

[0048] Figure 4 It is a process flow diagram of step S1 of the present invention;

[0049] Figure 5 It is a schematic diagram of the process flow of step S2 of the present invention;

[0050] Figure 6 It is a process flow diagram of step S3 of the present invention;

[0051] Figure 7 is a schematic diagram of the process flow of step S4 of the present invention;

[0052] Figure 8 is a schematic diagram of the process flow of step S5 of the present invention;

[0053] Fig. 9 It is a process flow diagram of step S6 of the present invention;

[0054] Fig.10 is a schematic diagram of the process flow of step S7 of the present invention;

[0055] Fig.11 It is a schematic diagram of the process flow of step S8 of the present invention.

[0056] In the figure: 100-driving substrate, 101-first insulating isolation layer, 102-first P-type semiconductor electrode transition layer, 200-first light-emitting layer, 201-first substrate, 202-first epitaxial layer, 203-first P-electrode layer, 204-first passivation layer, 205-first reflective layer, 206-second insulating isolation layer, 207-second P-type semiconductor electrode transition layer, 2071-short P-type semiconductor electrode transition layer, 2072-long P-type semiconductor electrode transition layer, 300-first connection layer, 301-first N-type semiconductor electrode transition layer, 302-first N-electrode grid, 3 03-third insulating isolation layer, 304-third P-type semiconductor electrode transition layer, 400-second light-emitting layer, 401-second substrate, 402-second epitaxial layer, 403-second P-electrode layer, 404-second passivation layer, 405-second reflective layer, 406-fourth insulating isolation layer, 407-fourth P-type semiconductor electrode transition layer, 500-second connecting layer, 501-second N-type semiconductor electrode transition layer, 502-second N-electrode grid, 503-fifth insulating isolation layer, 600-color conversion layer, 601-third reflective layer, 700-encapsulation layer, 701-lens structure. DETAILED DESCRIPTION

[0057] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] like Figure 1 As shown, the present invention provides a full-color MicroLED, including a driving substrate 100, a first insulating isolation layer 101 is deposited on the driving substrate 100, and a first P-type semiconductor electrode transition layer 102 is provided at the first insulating isolation layer 101 corresponding to the driving substrate electrode;

[0059] The first light-emitting layer 200 includes a second insulating isolation layer 206, on which a plurality of first light-emitting units arranged in an array are arranged, the first light-emitting units include a first epitaxial layer 202, a first P-electrode layer 203 is arranged at the bottom of the first epitaxial layer 202, a first passivation layer 204 and a first light-reflecting layer 205 are arranged in sequence on the sidewalls of the first epitaxial layer 202, a second P-type semiconductor electrode transition layer 207 is arranged at the second insulating isolation layer 206 corresponding to the first P-type semiconductor electrode transition layer 102, the second P-type semiconductor electrode transition layer 207 includes a short P-type semiconductor electrode transition layer 2071 and a long P-type semiconductor electrode transition layer 2072, the bottom of the first light-emitting unit is connected to the first P-type semiconductor electrode transition layer 102 via the short P-type semiconductor electrode transition layer 2071, and the long P-type semiconductor electrode transition layer 2072 runs through the second insulating isolation layer 206;

[0060] The first connection layer 300 includes a first N-type semiconductor electrode transition layer 301, the bottom of the first N-type semiconductor electrode transition layer 301 is bonded to the first light-emitting layer 200, a window is opened in the first N-type semiconductor electrode transition layer 301 corresponding to the long P-type semiconductor electrode transition layer 2072, a first N-electrode grid 302 is provided on the surface of the first N-type semiconductor electrode transition layer 301 away from the driving substrate 100, a third insulating isolation layer 303 is deposited above the first N-type semiconductor electrode transition layer 301, and a third P-type semiconductor electrode transition layer 304 is penetrated by the third insulating isolation layer 303 corresponding to the long P-type semiconductor electrode transition layer 2072;

[0061] The second light-emitting layer 400 includes a fourth insulating isolation layer 406, on which a plurality of second light-emitting units arranged in an array are disposed, the second light-emitting units include a second epitaxial layer 402, a second P-electrode layer 403 is disposed at the bottom of the second epitaxial layer 402, a second passivation layer 404 and a second light-reflecting layer 405 are sequentially disposed on the sidewalls of the second epitaxial layer 402, a fourth P-type semiconductor electrode transition layer 407 is disposed at the fourth insulating isolation layer 406 corresponding to the third P-type semiconductor electrode transition layer 303, and the bottom of the second light-emitting unit is connected to the third P-type semiconductor electrode transition layer 304 via the fourth P-type semiconductor electrode transition layer 407;

[0062] The second connection layer 500 includes a second N-type semiconductor electrode transition layer 501, the bottom of the second N-type semiconductor electrode transition layer 501 is bonded to the second light-emitting layer 400, a second N-electrode grid 502 is provided on the surface of the second N-type semiconductor electrode transition layer 501, a fifth insulating isolation layer 503 is deposited above the second N-type semiconductor electrode transition layer 501, a window is opened in the fifth insulating isolation layer 503 corresponding to the second light-emitting unit, a color conversion material is filled in the window of the fifth insulating isolation layer 503 to form a color conversion layer 600, and a third reflective layer 601 is provided on the side wall of the color conversion layer 600.

[0063] Among them, the driving substrate 100 is a silicon-based CMOS backplane, the first epitaxial layer 202 is a semiconductor material that excites green light, the second light-emitting unit 402 epitaxial layer is a semiconductor material that excites blue light, and the color conversion material is a quantum dot material, preferably a red quantum dot material, which can convert the blue light emitted by the second light-emitting unit into red light.

[0064] The three color pixel arrangement modes and the light-emitting area shapes can be selected in different distribution modes and shapes according to the needs. The projection area ratio of the first light-emitting unit, the second light-emitting unit and the color conversion layer on the top surface is 3:5~6:2~1. The projection of the first light-emitting unit, the second light-emitting unit and the color conversion layer on the top surface can be a triangle, a circle or a polygon. Figure 2 Five possible pixel arrangement modes and shapes are given. The dimensions of the light-emitting units are not necessarily the same and will be adjusted according to the brightness requirements. Those skilled in the art should understand that the present invention is not subject to the above Figure 2 Limitations of pixel arrangement in .

[0065] The first insulating isolation layer 101, the second insulating isolation layer 206, the third insulating isolation layer 303, the fourth insulating isolation layer 406, the fifth insulating isolation layer 503, the first passivation layer 204, and the second passivation layer 404 are transparent, non-conductive, and have a certain strength, such as SiO2, Al2O3, or Si3N4. The first P-electrode layer 203 and the second P-electrode layer 404 are ITO films. The first reflective layer 205, the second reflective layer 405, and the third reflective layer 601 are Ti / Al / TiN, Ti / Al / Ag, Ti / Al / ITO, or Ti / Al / SiO2 structures, preferably Ti / Al / TiN, wherein the thickness of the Ti layer is 5-10 nm, the thickness of the Al layer is 140-160 nm, and the thickness of the TiN layer is 10-15 nm.

[0066] The first P-type semiconductor electrode transition layer 102, the second P-type semiconductor electrode transition layer 207, the third P-type semiconductor electrode transition layer 304, and the fourth P-type semiconductor electrode transition layer 407 are made of metal materials, and the metal materials are Cu, Al, Sn, Au, Pt, Ti, or Cr. The first N-type semiconductor electrode transition layer 301 and the second N-type semiconductor electrode transition layer 501 are ITO films. The first N-electrode grid 302 and the second N-electrode grid 502 are materials with suitable stress / good conductivity / adhesion, and can be Cr / Pt / Au or Cr / Al / Au / Cu / Ti materials.

[0067] like Figure 3As shown, as another embodiment of the present invention, a packaging layer 700 is further provided on the surface of the second connection layer 500, and a lens structure 701 is provided on the surface of the packaging layer 700. The lens structure 701 corresponds to a single pixel or a single RGB unit, and a single RGB unit includes at least one R, G and B pixel. The packaging layer 700 is a transparent, non-conductive material, which can be SiO2, Al2O3 or Si3N4 material. The lens structure 701 is obtained by etching the packaging layer 700, and the shape can be hemispherical.

[0068] like Figures 4 to 11 As shown, the preparation method of the full-color MicroLED includes the following steps:

[0069] S1, a layer of SiO2 is deposited on the surface of the driving substrate 100 to form a first insulating isolation layer 101, and then windows are opened at the corresponding electrodes of the first insulating isolation layer 101 by photolithography-etching, and the surface of the first insulating isolation layer 101 is electroplated with metal and then chemically mechanically polished and flattened to form a first P-type semiconductor electrode transition layer 102;

[0070] S2. Processing the first epitaxial wafer, wherein the first epitaxial wafer includes a first substrate 201 and a first epitaxial layer 202. The processing of the first epitaxial wafer specifically includes:

[0071] S201, sputtering an ITO film on the surface of the first epitaxial layer 202 of the first epitaxial wafer, and then etching the ITO film by photolithography-etching to form a first P-electrode layer 203;

[0072] S202, continue etching the first epitaxial layer 202 by photolithography-etching to pattern it and form a first light-emitting unit;

[0073] S203, depositing a layer of SiO2 on the surface of the first epitaxial wafer to form a first passivation layer 204, then plating a composite metal layer on the surface of the first passivation layer 204 to form a first reflective layer 205, and removing the first passivation layer 204 and the first reflective layer 205 on the top of the first reflective unit by photolithography and etching to expose the first P electrode layer 203 on the top of the first light-emitting unit;

[0074] S204, depositing a layer of SiO2 above the light-emitting unit to form a second insulating isolation layer 206, and then opening a window in the second insulating isolation layer 206 corresponding to the first P-type semiconductor electrode transition layer by photolithography-etching;

[0075] S205, electroplating metal on the surface of the second insulating isolation layer 206 and then performing chemical mechanical polishing and flattening to form a second P-type semiconductor electrode transition layer 207, thereby completing the processing of the first epitaxial wafer;

[0076] S3, performing surface activation and pre-alignment on the first epitaxial wafer of step S2 and the chip of step S1, and then bonding the first epitaxial wafer and the chip by hybrid bonding, with the bonding accuracy being less than or equal to 0.5 μm, and finally removing the first substrate of the first epitaxial wafer;

[0077] S4, sputtering an ITO film on the surface of the first epitaxial wafer to form a first N-type semiconductor electrode transition layer 301, then plating a first N-electrode grid 302 on the surface of the first N-type semiconductor electrode transition layer 301 away from the drive substrate 100 through a photolithography-lift off process, opening a window in the first N-type semiconductor electrode transition layer 301 corresponding to the long P-type semiconductor electrode transition layer 2072, then depositing a layer of SiO2 on the first N-type semiconductor electrode transition layer 301 to form a third insulating isolation layer 303, then opening a window in the third insulating layer corresponding to the long P-type semiconductor electrode transition layer 2072 through a photolithography-etching method, finally electroplating metal on the surface of the third insulating isolation layer 303 and then chemically mechanically polishing and flattening it to form a third P-type semiconductor electrode transition layer 304, and completing the preparation of the first connection layer;

[0078] S5, processing the second epitaxial wafer in the same manner as in step S2, the second epitaxial wafer comprising a second substrate 401 and a second epitaxial layer 402, completing the preparation of a second light-emitting unit of a second light-emitting layer, a fourth insulating isolation layer 406 and a fourth P-type semiconductor electrode transition layer 407;

[0079] S6, the second epitaxial wafer of step S5 and the chip of step S4 are surface activated and pre-aligned, and then the second epitaxial wafer and the chip are bonded by hybrid bonding, and the bonding accuracy is less than or equal to 0.5 μm, and finally the second substrate 401 of the second epitaxial wafer is removed;

[0080] S7, sputtering an ITO film on the surface of the second epitaxial wafer to form a second N-type semiconductor electrode transition layer 501, then plating a second N-electrode grid 502 on the surface of the second N-type semiconductor electrode transition layer by a photolithography-lift-off process, and finally depositing a layer of SiO2 on the second N-type semiconductor electrode transition layer 501 to form a fifth insulating isolation layer 503, thereby completing the preparation of the second connection layer;

[0081] S8. According to the chip design, a window is opened in the fifth insulating isolation layer 503 corresponding to the second light-emitting unit by photolithography-etching, a composite metal layer is plated on the surface of the fifth insulating isolation layer 503, and then the composite metal layer in excess is removed by photolithography-etching, leaving only the inner wall position of the window of the fifth insulating isolation layer 503 to form a third reflective layer 601, and finally quantum dot material is filled by photolithography to form a color conversion layer 600.

[0082] Wherein, the line widths of the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer and the third P-type semiconductor electrode transition layer are 1-2 μm.

[0083] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0084] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A full-color MicroLED, characterized in that: It includes a driving substrate, a first insulating isolation layer is deposited on the driving substrate, and a first P-type semiconductor electrode transition layer is provided at the first insulating isolation layer corresponding to the driving substrate electrode; A first light-emitting layer includes a second insulating isolation layer, a plurality of first light-emitting units arranged in an array are arranged on the second insulating isolation layer, a second P-type semiconductor electrode transition layer is arranged at the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer includes a short P-type semiconductor electrode transition layer and a long P-type semiconductor electrode transition layer, the bottom of the first light-emitting unit is connected to the first P-type semiconductor electrode transition layer through the short P-type semiconductor electrode transition layer, and the long P-type semiconductor electrode transition layer runs through the second insulating isolation layer; The first connection layer includes a first N-type semiconductor electrode transition layer, the bottom of the first N-type semiconductor electrode transition layer is connected to the first light-emitting layer, a window is opened in the first N-type semiconductor electrode transition layer corresponding to the long P-type semiconductor electrode transition layer, a first N-electrode grid is provided on the surface of the first N-type semiconductor electrode transition layer away from the driving substrate, a third insulating isolation layer is deposited above the first N-type semiconductor electrode transition layer, and a third P-type semiconductor electrode transition layer is provided through the third insulating isolation layer corresponding to the long P-type semiconductor electrode transition layer; The second light-emitting layer includes a fourth insulating isolation layer, a plurality of second light-emitting units arranged in an array are arranged on the fourth insulating isolation layer, a fourth P-type semiconductor electrode transition layer is arranged at a position of the fourth insulating isolation layer corresponding to the third P-type semiconductor electrode transition layer, and the bottom of the second light-emitting unit is connected to the third P-type semiconductor electrode transition layer through the fourth P-type semiconductor electrode transition layer; The second connection layer includes a second N-type semiconductor electrode transition layer, the bottom of the second N-type semiconductor electrode transition layer is connected to the second light-emitting layer, the surface of the second N-type semiconductor electrode transition layer is provided with a second N-electrode grid, a fifth insulating isolation layer is deposited above the second N-type semiconductor electrode transition layer, a window is opened at a portion of the fifth insulating isolation layer corresponding to the second light-emitting unit, and a color conversion material is filled in the window of the fifth insulating isolation layer to form a color conversion layer.

2. The full-color MicroLED according to claim 1, characterized in that: The driving substrate is a silicon-based CMOS backplane.

3. The full-color MicroLED according to claim 1, characterized in that: The first insulating isolation layer, the second insulating isolation layer, the third insulating isolation layer, the fourth insulating isolation layer and the fifth insulating isolation layer are made of SiO2, Al2O3 or Si3N4 materials.

4. The full-color MicroLED according to claim 1, characterized in that: The first light-emitting unit includes a first epitaxial layer, a first P-electrode layer is disposed at the bottom of the first epitaxial layer, a first passivation layer and a first reflective layer are disposed on the sidewall of the first epitaxial layer in sequence, and the second light-emitting unit has the same structure as the first light-emitting unit.

5. The full-color MicroLED according to claim 4, characterized in that: The epitaxial layer of the first light-emitting unit is a semiconductor material that excites green light, and the epitaxial layer of the second light-emitting unit is a semiconductor material that excites blue light.

6. The full-color MicroLED according to claim 4, characterized in that: The projections of the first light-emitting unit, the second light-emitting unit and the color conversion layer on the top surface may be triangular, circular or polygonal.

7. The full-color MicroLED according to claim 4, characterized in that: The first P-electrode layer is an ITO thin film.

8. The full-color MicroLED according to claim 4, characterized in that: The first passivation layer is made of SiO2, Al2O3 or Si3N4 material.

9. The full-color MicroLED according to claim 4, characterized in that: The first light reflecting layer is a Ti / Al / TiN, Ti / Al / Ag, Ti / A1 / ITO or Ti / Al / SiO2 structure.

10. The full-color MicroLED according to claim 1, characterized in that: The first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer, the third P-type semiconductor electrode transition layer, and the fourth P-type semiconductor electrode transition layer are made of metal materials, and the metal materials are Cu, Al, Sn, Au, Pt, Ti or Cr.

11. The full-color MicroLED according to claim 1, characterized in that: The first N-type semiconductor electrode transition layer and the second N-type semiconductor electrode transition layer are ITO films.

12. The full-color MicroLED according to claim 1, characterized in that: The first N-electrode grid and the second N-electrode grid are made of Cr / Pt / Au or Cr / Al / Au / Cu / Ti materials.

13. The full-color MicroLED according to claim 1, characterized in that: The color conversion material is a quantum dot material, the quantum dot material is a red quantum dot material, and a third light reflecting layer is disposed on the side wall of the color conversion layer.

14. The method for preparing a full-color MicroLED according to claim 1, characterized in that: An encapsulation layer is also provided on the surface of the second connection layer. A lens structure is provided on the surface of the encapsulation layer. The lens structure corresponds to a single pixel or a single RGB unit. The single RGB unit includes at least one R, G and B pixel.

15. The method for preparing a full-color MicroLED according to any one of claims 1 to 13, characterized in that: The following steps are involved: S1, depositing a layer of SiO2 on the surface of the driving substrate to form a first insulating isolation layer, then opening windows at the corresponding electrodes of the first insulating isolation layer by photolithography-etching, electroplating metal on the surface of the first insulating isolation layer and then chemically mechanically polishing and flattening it to form a first P-type semiconductor electrode transition layer; S2, processing the first epitaxial wafer, forming a first light-emitting unit at a corresponding position according to the chip design, then depositing a layer of SiO2 on the light-emitting unit to form a second insulating isolation layer, and then opening a window in the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer by photolithography-etching, electroplating the surface of the second insulating isolation layer with metal, and then chemically and mechanically polishing and flattening it to form a second P-type semiconductor electrode transition layer; S3, performing surface activation and pre-alignment on the first epitaxial wafer of step S2 and the chip of step S1, then bonding the first epitaxial wafer and the chip by hybrid bonding, and finally removing the substrate of the first epitaxial wafer; S4, sputtering an ITO film on the surface of the first epitaxial wafer to form a first N-type semiconductor electrode transition layer, then plating a first N-electrode grid on the surface of the first N-type semiconductor electrode transition layer away from the driving substrate through a photolithography-lift off process, opening a window in the first N-type semiconductor electrode transition layer corresponding to the long P-type semiconductor electrode transition layer, then depositing a layer of SiO2 on the first N-type semiconductor electrode transition layer to form a third insulating isolation layer, then opening a window in the third insulating layer corresponding to the long P-type semiconductor electrode transition layer through a photolithography-etching method, finally electroplating metal on the surface of the third insulating isolation layer and then chemically mechanically polishing and flattening it to form a third P-type semiconductor electrode transition layer, thereby completing the preparation of the first connection layer; S5, processing the second epitaxial wafer in the same manner as in step S2, completing the preparation of the second light-emitting unit of the second light-emitting layer, the fourth insulating isolation layer and the fourth P-type semiconductor electrode transition layer; S6, performing surface activation and pre-alignment on the second epitaxial wafer of step S5 and the chip of step S4, then bonding the second epitaxial wafer and the chip by hybrid bonding, and finally removing the substrate of the second epitaxial wafer; S7, sputtering an ITO film on the surface of the second epitaxial wafer to form a second N-type semiconductor electrode transition layer, then plating a second N-electrode grid on the surface of the second N-type semiconductor electrode transition layer by a photolithography-lift-off process, and finally depositing a layer of SiO2 on the second N-type semiconductor electrode transition layer to form a fifth insulating isolation layer, thereby completing the preparation of the second connection layer; S8. According to the chip design, a window is opened at the second light-emitting unit corresponding to the fifth insulating isolation layer by photolithography-etching, a composite metal layer is plated on the surface of the fifth insulating isolation layer, and then the composite metal layer in excess is removed by photolithography-etching, leaving only the inner wall of the window of the fifth insulating isolation layer to form a third reflective layer, and finally quantum dot material is filled by photolithography to form a color conversion layer.

16. The method for preparing a full-color MicroLED according to claim 15, characterized in that: The processing of the first epitaxial wafer in step S2 specifically includes the following steps: S201, sputtering an ITO film on the surface of the first epitaxial layer of the first epitaxial wafer, and then etching the ITO film by photolithography-etching to form a first P-electrode layer; S202, continue etching the first epitaxial layer by photolithography-etching to pattern it, and form a first light-emitting unit; S203, depositing a layer of SiO2 on the surface of the first epitaxial wafer to form a first passivation layer, then plating a composite metal layer on the surface of the first passivation layer to form a first reflective layer, and removing the first passivation layer and the first reflective layer on the top of the first reflective unit by photolithography and etching to expose the first P electrode layer on the top of the first light-emitting unit; S204, depositing a layer of SiO2 on the light-emitting unit to form a second insulating isolation layer, and then opening a window in the second insulating isolation layer corresponding to the first P-type semiconductor electrode transition layer by photolithography-etching; S205, electroplating metal on the surface of the second insulating isolation layer and then performing chemical mechanical polishing to flatten it, forming a second P-type semiconductor electrode transition layer, and completing the processing of the first epitaxial wafer.

17. The method for preparing a full-color MicroLED according to claim 16, characterized in that: The overall processing steps of the second epitaxial wafer in step S5 are the same as those of the first epitaxial wafer, except that in step S204, a window is opened in the fourth insulating isolation layer corresponding to the third P-type semiconductor electrode transition layer.

18. The method for preparing a full-color MicroLED according to claim 15, characterized in that: The line widths of the first P-type semiconductor electrode transition layer, the second P-type semiconductor electrode transition layer and the third P-type semiconductor electrode transition layer are 1-2 μm.

19. The method for preparing a full-color MicroLED according to claim 15, characterized in that: The bonding accuracy of the first epitaxial wafer in step S3 and the second epitaxial wafer in step S6 are both less than or equal to 0.5 μm.

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