A method for preparing a high light efficiency micro-OLED structure

Abstract

This invention discloses a method for fabricating a high-efficiency Micro-OLED structure, belonging to the field of OLED display technology. Addressing the problems of insufficient brightness, severe large-angle scattering light loss, and bottlenecks in improving light extraction efficiency in existing silicon-based Micro-OLEDs, this invention fabricates a silicon dioxide / silicon nitride bilayer dielectric layer on a CMOS substrate. Utilizing the difference in etching rates between the two layers, a parabolic reflective bowl anode is fabricated. The pixel definition layer, organic light-emitting layer, thin-film encapsulation layer, color filter layer, and planarization layer are then fabricated sequentially. Finally, a microlens array coaxial with the reflective bowl is fabricated, forming a synergistic light-gathering system. This invention can significantly reduce internal light loss in the device, significantly improve peak brightness and light extraction efficiency, is compatible with existing mass production processes, and meets the high-brightness application requirements of AR / VR near-eye displays.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of OLED display, more particularly, to a preparation method of a high light efficiency Micro-OLED structure. BACKGROUND

[0002] With the rapid landing of the metaverse industry, augmented reality (AR) and virtual reality (VR) near-eye display devices are experiencing large-scale development. Micro display technology, as the core component of near-eye display terminals, directly determines the imaging quality, power consumption, and overall volume of the product. Among them, silicon-based Micro-OLED technology, with its inherent advantages of ultra-high pixel density (PPI), low power consumption, ultra-small volume, nanosecond-level response speed, wide viewing angle, and self-emission, has become the mainstream solution for mid-to-high-end AR / VR near-eye display devices. It is the core research and development focus in the current semiconductor display field.

[0003] In silicon-based Micro-OLED devices with a top-emitting structure, light efficiency and peak brightness are the core indicators that restrict their large-scale application in AR scenarios. Unlike the closed and dark environment of VR devices, AR devices need to directly cope with outdoor strong light scenarios, which puts extremely high requirements on the peak brightness of display panels. However, the brightness of current commercial full-color silicon-based Micro-OLED products generally cannot meet the outdoor high-brightness usage requirements, which has become a core bottleneck restricting the development of the industry.

[0004] The current mainstream approach to improving Micro-OLED brightness in the industry mainly focuses on optimizing the reflectivity of anode materials and improving the light-emitting efficiency of organic light-emitting layers. Among them, the anode, as the core reflective layer of the top-emitting Micro-OLED device, its reflective performance directly determines the light extraction efficiency. However, after years of technical iteration, the material reflectivity of Ag, Al, and other pure metal anodes has approached the theoretical limit, and the space for improving brightness through material system optimization is very limited, encountering a significant technical bottleneck.

[0005] To further break through the brightness bottleneck, the industry began to try to introduce optical microstructure to improve light efficiency, such as single microlens array, simple concave anode structure and the like. But the existing optical structure scheme has obvious technical defects: first, single microlens array can only focus on small-angle light after emission, and cannot recycle large-angle scattered light emitted by the organic light-emitting layer. A large amount of large-angle light is totally reflected and absorbed by the material inside the device, resulting in serious light loss. Second, the existing simple reflective anode structure is mostly regular arc or planar concave, which cannot realize directional gathering of light, has low light gathering efficiency, and has poor process compatibility with subsequent pixel definition layer and organic light-emitting layer. Third, the existing scheme does not realize the collaborative design of the anode end light gathering structure and the light emitting end microlens array, cannot form the secondary light gathering effect of one-time gathering reflection + secondary focusing emission, and the improvement range of light efficiency is limited, which is always difficult to meet the high brightness use demand of AR equipment. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a high light efficiency Micro-OLED structure to solve the technical problems existing in the background art.

[0007] The technical scheme of the present application provides a preparation method of a high light efficiency Micro-OLED structure, which takes a wafer with a CMOS structure as a substrate, prepares a parabolic curved surface reflecting bowl anode structure through etching rate difference, and realizes light gathering and brightness enhancement in combination with a microlens array structure. The preparation steps are as follows:

[0008] S1, substrate dielectric layer preparation: SiO2 film layer and SiN film layer are sequentially deposited on the surface of the CMOS substrate by chemical vapor deposition process to form a double-layer dielectric layer;

[0009] S2, reflecting bowl morphology forming and metal anode preparation: the double-layer dielectric layer is subjected to photoetching and dry etching, and a parabolic curved surface bowl-shaped morphology is formed by utilizing the etching rate difference between SiN and SiO2; then, an Ag / Al metal layer is deposited by evaporation or magnetron sputtering, and a reflecting bowl metal anode is formed by photoetching and dry etching patterning.

[0010] S3, anode insulation filling and transparent electrode forming: SiO2 film layer is deposited on the substrate and etched to only leave SiO2 insulation filling layer inside the reflecting bowl; then, ITO film layer is deposited and patterned to form a transparent anode matched with the inner wall of the reflecting bowl, and the preparation of the bowl-shaped anode reflecting structure is completed;

[0011] S4, pixel definition, light-emitting layer and encapsulation layer preparation: pixel definition layer is prepared on the anode structure by film forming, top-emitting organic light-emitting layer is prepared by evaporation, and thin film encapsulation layer is prepared by chemical vapor deposition and atomic layer deposition composite process;

[0012] S5, Color filter and planarization precursor preparation: A CF color filter layer is prepared on the thin film encapsulation layer by photolithography and development; then a TopOC planarization layer is prepared on the CF layer, and ReflowPR photoresist is simultaneously spin-coated to form a LENS microlens precursor layer.

[0013] S6, Microlens Array Forming and Device Completion: The ReflowPR layer is thermally reflow shaped and then dry-etched to transfer the pattern, forming a MicroLens microlens array that matches the reflective bowl below, thus completing the device fabrication.

[0014] In a preferred embodiment, in S1, the SiO2 film thickness is 0.5μm-2μm, and the SiN film thickness is 0.5μm-2μm.

[0015] In a preferred embodiment, in S2, the parabolic bowl-shaped morphology is formed by adjusting the etching gas ratio, etching rate, and etching time; the Ag / Al metal layer deposition thickness is 50nm-200nm.

[0016] In a preferred embodiment, in step S3, the ITO film layer has a deposition thickness of 20nm-200nm, and the patterned ITO layer completely covers the SiO2 insulating filling layer inside the reflective bowl, perfectly fitting the curved contour.

[0017] In a preferred embodiment, in step S4, the thin film encapsulation layer is a stacked structure of Al2O3 and SiN, wherein the thickness of the Al2O3 layer is 0.1 μm and the thickness of the SiN layer is 1.9 μm.

[0018] In a preferred embodiment, the etching processes in S2, S3, and S6 are all dry etching processes, and all photolithography patterning processes use spin-coated photoresist, followed by pre-baking, development, and post-baking to complete the pattern definition.

[0019] In a preferred embodiment, in step S6, the MicroLens microlens is made of any one of SiO2, SiN, or PI, and its curvature parameters are adapted to the curvature of the parabolic reflector bowl below.

[0020] In a preferred embodiment, in step S6, the MicroLens microlens array is arranged in a regular pattern, and the geometric center of each microlens is coaxially aligned with the geometric center of the corresponding reflector bowl below.

[0021] In a preferred embodiment, in step S4, the light-emitting surface of the organic light-emitting layer faces the thin film encapsulation layer and the subsequent optical layer. The large-angle scattered light emitted by the organic light-emitting layer is focused into small-angle emitted light by the parabolic reflector bowl, and then vertically emitted after being focused twice by the microlens array above.

[0022] In a preferred embodiment, the fabricated Micro-OLED structure comprises, from bottom to top: a CMOS substrate, a SiO2 / SiN bilayer dielectric layer, a parabolic reflective bowl anode structure, a pixel definition layer, an organic light-emitting layer, an Al2O3 / SiN stacked encapsulation layer, a CF color filter layer, a TopOC planarization layer, and a MicroLens microlens array. The parabolic reflective bowl anode structure and the MicroLens microlens array work together to achieve secondary light focusing, reduce light scattering loss, and improve the device's light extraction efficiency and peak brightness.

[0023] The beneficial effects of the technical solution of this invention are:

[0024] This invention addresses the industry bottlenecks of existing silicon-based top-emission Micro-OLEDs, including insufficient brightness, low light extraction efficiency, and severe light loss due to large-angle scattering. It utilizes the difference in etching rates between silicon nitride and silicon dioxide to fabricate a parabolic reflective bowl anode, paired with a microlens array coaxial with the reflective bowl, forming a synergistic light-gathering system of "primary focused reflection + secondary focused emission." This significantly recovers large-angle scattered light, reduces internal light loss, and achieves a leap forward in peak brightness and external quantum efficiency. Attached Figure Description

[0025] Figure 1 This is a cross-sectional schematic diagram of the double-layer dielectric substrate fabricated on the surface of a CMOS substrate according to the present invention;

[0026] Figure 2 This is a cross-sectional schematic diagram of the double-layer dielectric layer after etching to form a parabolic bowl-shaped morphology according to the present invention;

[0027] Figure 3 This is a schematic cross-sectional view of the substrate after the metal anode layer has been deposited on the entire surface of the substrate according to the present invention;

[0028] Figure 4 This is a cross-sectional schematic diagram of the metal anode layer patterning process of the present invention to form a reflective bowl metal anode structure that fits the parabolic surface;

[0029] Figure 5 This is a schematic cross-sectional view of the substrate after a silicon dioxide film has been deposited on the entire surface of the substrate according to the present invention;

[0030] Figure 6 This is a schematic diagram of the cross-section after etching the silicon dioxide film layer in this invention, leaving only the insulating filling layer inside the reflector bowl.

[0031] Figure 7 This is a cross-sectional schematic diagram of the substrate after the indium tin oxide transparent anode layer is deposited on the entire surface of the substrate according to the present invention;

[0032] Figure 8This is a cross-sectional schematic diagram of the bowl-shaped anode reflective structure after the transparent anode layer has been patterned according to the present invention.

[0033] Figure 9 This is a cross-sectional schematic diagram of the pixel definition layer after it has been fabricated on the substrate surface according to the present invention;

[0034] Figure 10 This is a cross-sectional schematic diagram of the organic light-emitting layer and the thin film encapsulation layer after they have been sequentially prepared according to the present invention;

[0035] Figure 11 This is a cross-sectional schematic diagram of the present invention after a color filter layer is fabricated on the surface of the thin film encapsulation layer;

[0036] Figure 12 This is a cross-sectional schematic diagram showing the preparation of a top flattened layer on the surface of a color filter layer and the simultaneous preparation of a microlens precursor layer, as per the present invention.

[0037] Figure 13 This is a cross-sectional schematic diagram of the microlens precursor layer after undergoing thermal reflow treatment to form a spherical lens morphology precursor pattern according to the present invention.

[0038] Figure 14 This is a cross-sectional schematic diagram of the Micro-OLED device fabricated after the etching and transfer pattern is formed to create a microlens array.

[0039] Figure 15 This is a detailed enlarged schematic diagram of the parabolic surface reflective bowl anode structure, which is the core of this invention.

[0040] Figure 16 This is a schematic diagram of the MicroLens microlens array arrangement structure of the present invention. Detailed Implementation

[0041] The present invention will now be described in further detail. The embodiments of the invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0042] The core of the preparation method disclosed in this invention is to prepare a parabolic reflective bowl anode structure by using the difference in etching rates between silicon nitride and silicon dioxide, and to combine it with a microlens array at the light-emitting end to form a secondary light-concentrating system of primary convergence reflection + secondary focusing emission, thereby improving the light-emitting efficiency and peak brightness of silicon-based top-emitting Micro-OLED.

[0043] Example 1

[0044] like Figure 1 As shown, an 8-inch silicon wafer with a CMOS driving circuit structure was selected as the substrate. Plasma-enhanced chemical vapor deposition was used to sequentially deposit a silicon dioxide film and a silicon nitride film on the substrate surface. The silicon dioxide film was deposited with a thickness of 1 μm, and the deposition process parameters were: a silane to nitrous oxide flow rate ratio of 1:10, a deposition temperature of 300℃, a chamber pressure of 5 Torr, and an RF power of 150W. The silicon nitride film was deposited with a thickness of 1 μm, and the deposition process parameters were: a silane to ammonia flow rate ratio of 1:5, a deposition temperature of 300℃, a chamber pressure of 3 Torr, and an RF power of 200W, forming a bilayer dielectric substrate prepared by an anode.

[0045] like Figure 2 As shown, a positive photoresist (AZ5214) was spin-coated onto the silicon nitride film surface at a spin speed of 4000 rpm for 30 seconds. After pre-baking at 100°C for 90 seconds, the film was exposed and developed using a photomask to form a reflective bowl-shaped photoresist mask. Inductively coupled plasma dry etching was used to etch the double dielectric layer. The etching gas was a mixture of sulfur hexafluoride and oxygen at a flow ratio of 8:1, with a chamber pressure of 10 mTorr and an RF power of 300 W. By adjusting the etching parameters, the silicon nitride to silicon dioxide etching selectivity ratio was controlled to 3:1. Utilizing the difference in their etching rates, the etching time was 120 seconds, resulting in a continuous parabolic bowl-shaped morphology with an opening diameter of 5 μm, a depth of 1 μm, and a radius of curvature of 3 μm.

[0046] like Figure 3 As shown, after removing the photoresist mask, an electron beam thermal evaporation process is used to deposit a silver metal layer as the metal anode layer on the entire surface of the substrate. The deposition thickness is 100 nm, and the vacuum degree of the deposition chamber is ≤5×10⁻⁻⁻⁶. 4 Pa, deposition rate 0.5 nm / s.

[0047] like Figure 4 As shown, the photoresist pattern is spin-coated again, and the silver metal layer outside the reflector bowl area is removed by inductively coupled plasma dry etching, leaving the silver metal anode that is completely attached to the parabolic surface, forming the reflector bowl metal anode structure. The etching gas is a mixture of boron trichloride and chlorine, and the etching time is 60s.

[0048] like Figure 5 As shown, a silicon dioxide film with a thickness of 1 μm was deposited on the entire surface of the substrate using plasma-enhanced chemical vapor deposition (PECVD). Figure 6 As shown, after spin-coating photoresist for patterning, the silicon dioxide film layer outside the reflector bowl area is removed by inductively coupled plasma dry etching, leaving only the silicon dioxide insulating filling layer inside the reflector bowl. The etching ratio of silicon dioxide to photoresist is 15:1, and the etching time is 80 seconds.Figure 7 As shown, an indium tin oxide film was deposited as a transparent anode layer on the entire surface of the substrate using magnetron sputtering, with a deposition thickness of 100 nm, a sputtering power of 100 W, an argon flow rate of 20 sccm, and a chamber temperature of 25 °C. Figure 8 As shown, after spin-coating photoresist for patterning, the indium tin oxide film layer outside the reflective bowl region is removed by inductively coupled plasma dry etching to form a transparent anode that perfectly matches the inner wall of the parabolic reflective bowl, thus completing the fabrication of the bowl-shaped anode reflective structure. Details of the core stacked structure of the parabolic reflective bowl anode are shown in [link to details]. Figure 15 .

[0049] like Figure 9 As shown, a pixel definition layer is prepared on the substrate surface using a spin coating process. The material is negative photoresist with a thickness of 1.5 μm. After photolithography and development, an opening pattern corresponding to the anode pixel is formed, and the layer is cured at 230°C for 2 hours.

[0050] like Figure 10 As shown, the substrate is fed into a vacuum evaporation machine, and a top-emitting organic light-emitting layer is sequentially deposited within the pixel opening. The vacuum degree of the evaporation chamber is ≤3×10⁻ 5 Pa, the organic light-emitting layer consists of, from bottom to top: hole injection layer HAT-CN, hole transport layer TAPC, red-green-blue tri-color light-emitting layer EML, electron transport layer TPBi, and electron injection layer LiF. After the organic light-emitting layer is prepared, an aluminum oxide film with a thickness of 0.1 μm is prepared by atomic layer deposition at a deposition temperature of 80 °C. Then, a silicon nitride film with a thickness of 1.9 μm is prepared by plasma-enhanced chemical vapor deposition to form a thin film encapsulation layer of aluminum oxide / silicon nitride stack, completing the water and oxygen barrier encapsulation of the device.

[0051] like Figure 11 As shown, colored photoresist is spin-coated onto the surface of the thin film encapsulation layer, and then red, green and blue color filter layers are prepared sequentially through photolithography and development. The thickness of the single color block is 1.5μm, and it is precisely aligned with the light-emitting pixels below to complete the colorization preparation.

[0052] like Figure 12 As shown, an organic planarization material, model JSROC6000, was spin-coated onto the surface of the color filter layer at a spin speed of 3000 rpm and a thickness of 2 μm. After photolithography development and curing at 200℃ for 1 hour, a top planarization layer was formed, filling the surface steps and undulations of the color filter layer. Simultaneously, a reflow photoresist with a thickness of 3 μm was spin-coated onto the surface of the top planarization layer to form a microlens precursor layer.

[0053] like Figure 13 As shown, the substrate is subjected to thermal reflow treatment at a reflow temperature of 160°C and a reflow time of 90s, so that the reflowed photoresist forms a precursor pattern with a spherical lens shape under the action of surface tension.

[0054] like Figure 14 As shown, an inductively coupled plasma dry etching process was employed, controlling the etching selectivity ratio of photoresist to top planarization layer to be 1:1. The reflowed spherical pattern was transferred to the planarization layer, with an etching time of 150 s, forming a microlens array coaxially corresponding to the lower reflective bowl. The radius of curvature of each microlens is 5 μm, and the array pitch is consistent with the pixel pitch, thus completing the fabrication of a high-efficiency silicon-based top-emission Micro-OLED structure. The overall array arrangement structure of the MicroLens microlenses is detailed in [the diagram]. Figure 16 .

[0055] Example 2

[0056] The difference between this embodiment and the preferred embodiment described above lies only in the adjustment of the core process parameters; the remaining process steps and parameters are completely identical. The adjustments include: the deposition thickness of both the silicon dioxide and silicon nitride films is 0.5 μm; the metal anode layer is an aluminum metal layer with a deposition thickness of 50 nm; the parabolic reflector bowl has an opening diameter of 3 μm, a depth of 0.5 μm, and a radius of curvature of 2 μm; the indium tin oxide film has a deposition thickness of 20 nm; the microlens array is fabricated using silicon dioxide, shaped by plasma-enhanced chemical vapor deposition followed by etching, with a radius of curvature of 2 μm for each microlens.

[0057] Comparison

[0058] To accurately verify the necessity and technical effect of each core technical feature of the present invention, five sets of control examples were set up. Except for the single variable difference that was clearly marked, all other substrate selection, process parameters, material system and preparation environment of the control examples were completely consistent with the above preferred embodiments, strictly following the single variable principle to ensure that the test results can be directly attributed to the variable difference.

[0059] Comparative Example 1: Existing Planar Anode Scheme

[0060] This comparative example uses a common industry-standard solution. Instead of fabricating a parabolic reflective bowl anode structure, a planar silver anode structure is directly used. All other process steps and parameters are consistent with the preferred embodiment.

[0061] Comparative Example 2: No Co-concentration Scheme

[0062] This comparative example only fabricates a parabolic reflective bowl anode structure and does not fabricate a top microlens array, thus failing to achieve the synergistic brightening effect of "reflective focusing + lens focusing". The remaining process steps and parameters are consistent with the preferred embodiment.

[0063] Comparative Example 3: Ordinary Arc-shaped Surface Reflective Bowl Scheme

[0064] This comparative example replaces the parabolic surface reflector bowl with a common circular arc surface reflector bowl used in the industry. The radius of curvature of the circular arc is consistent with the curvature of the vertex of the parabolic surface in the preferred embodiment. The remaining structure, process steps and parameters are consistent with the preferred embodiment.

[0065] Comparative Example 4: Color Filter and Planarization Layer Order Reversed

[0066] This comparative example reverses the preparation order of the color filter layer and the top planarization layer. First, the top planarization layer is prepared on the surface of the thin film encapsulation layer, and then the color filter layer is prepared on the surface of the planarization layer. The remaining structure, process steps and parameters are consistent with the preferred embodiment.

[0067] Comparative Example 5: Insulation Filling Layer Scheme for the Internal Part of the Reflective Bowl

[0068] This comparative example omits the silicon dioxide insulating filling layer inside the reflector bowl and directly deposits an indium tin oxide transparent anode layer on the surface of the metal anode layer. The remaining structure, process steps, and parameters are consistent with the preferred embodiment.

[0069] Performance testing and effect verification

[0070] Using a spectroradiometer, external quantum efficiency testing system, semiconductor parameter analyzer, and accelerated aging test chamber, comprehensive performance tests were conducted on the devices prepared in the above-mentioned preferred embodiment, parameter adjustment embodiment, and five comparative examples under standard atmospheric conditions at room temperature (25℃), rated driving voltage (3.3V). The test results are shown in the table below:

[0071] Peak luminance (cd / m2) External quantum efficiency (EQE) Light ray scattering loss rate Operating leakage current (nA) 1000 hour luminance retention rate Luminance improvement amplitude (relative to Comparative Example 1) Example 1 12800 18.2% 12.5% 1.2 92.3% 156% Example 2 11200 16.7% 15.3% 1.8 90.1% 124% Comparative Example 1 5000 7.8% 48.2% 2.5 85.6% 0% Comparative Example 2 7600 11.5% 29.7% 1.3 91.7% 52% Comparative Example 3 9100 13.4% 22.6% 1.4 91.2% 82% Comparative Example 4 6800 10.1% 35.9% 1.3 90.8% 36% Comparative Example 5 8300 12.2% 26.4% 8.7 72.5% 66%

[0072] As shown in the table above, the peak brightness of Embodiment 1 of the present invention is 156% higher than that of the conventional planar anode solution in the industry, the external quantum efficiency is increased by more than 130%, the light scattering loss rate is reduced from 48.2% to 12.5%, while maintaining extremely low leakage current and excellent long-term working stability, achieving a leapfrog improvement in core performance.

[0073] Comparison of Examples 1, 2, and 3 verifies that a single reflector bowl structure, a single microlens structure, and a conventional circular arc reflector bowl cannot achieve the optimal light-gathering effect. Only the synergistic design of the parabolic surface reflector bowl and coaxial microlens array of this invention can realize a complete light-gathering system of "first-time focusing reflection + second-time focusing emission", maximizing the recovery of large-angle scattered light.

[0074] Comparative Example 4 verifies that the process sequence of first preparing the color filter layer and then preparing the top planarization layer can fill the surface undulations of the color filter with the planarization layer, providing a flat substrate for microlens fabrication and significantly reducing light loss caused by lens morphology distortion. However, when the sequence is reversed, the planarization layer completely loses its function, the microlens forming quality decreases, and the device brightness and light extraction efficiency are greatly reduced.

[0075] Comparative Example 5 verifies that the silica insulating filling layer inside the reflector bowl can effectively avoid the risk of leakage between the metal anode and the transparent anode, while providing a uniform film substrate for the transparent anode, greatly improving the working stability and service life of the device; omitting this structure increases the leakage current of the device by more than 7 times, and the brightness decay is significantly accelerated over long-term operation.

[0076] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A method for fabricating a high light-output efficiency Micro-OLED structure, characterized in that, Using a CMOS-structured wafer as a substrate, a parabolic reflective bowl anode structure is fabricated through differential etching rates, and combined with a microlens array structure to achieve focused light enhancement. The fabrication steps are as follows: S1, Substrate dielectric layer preparation: SiO2 film and SiN film are sequentially deposited on the surface of CMOS substrate by chemical vapor deposition process to form a double dielectric layer; S2, Reflective Bowl Morphology Formation and Metal Anode Fabrication: The double dielectric layer is etched by photolithography and dry etching. Taking advantage of the difference in etching rates between SiN and SiO2, a parabolic curved bowl morphology is formed by etching. Then, Ag / Al metal layer is deposited by vapor deposition or magnetron sputtering. The layer is then patterned by photolithography and dry etching to form a reflective bowl metal anode that fits the curved surface. S3, Anode Insulation Filling and Transparent Electrode Forming: A SiO2 film is deposited and etched on the substrate, leaving only the SiO2 insulation filling layer inside the reflective bowl; an ITO film is then deposited and patterned to form a transparent anode that fits the inner wall of the reflective bowl, thus completing the fabrication of the bowl-shaped anode reflective structure; S4, Pixel definition, light-emitting layer and encapsulation layer preparation: A pixel definition layer is prepared by film deposition on the anode structure, a top-emitting organic light-emitting layer is prepared by evaporation, and a thin film encapsulation layer is prepared by a composite process of chemical vapor deposition and atomic layer deposition. S5, Color filter and planarization precursor preparation: A CF color filter layer is prepared on the thin film encapsulation layer by photolithography and development; then a TopOC planarization layer is prepared on the CF layer, and ReflowPR photoresist is simultaneously spin-coated to form a LENS microlens precursor layer. S6, Microlens Array Forming and Device Completion: The ReflowPR layer is thermally reflow shaped and then dry-etched to transfer the pattern, forming a MicroLens microlens array that matches the reflective bowl below, thus completing the device fabrication.

2. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S1, the thickness of the SiO2 film is 0.5μm-2μm, and the thickness of the SiN film is 0.5μm-2μm.

3. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S2, the parabolic bowl-shaped morphology is formed by adjusting the etching gas ratio, etching rate and etching time; the Ag / Al metal layer deposition thickness is 50nm-200nm.

4. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S3, the ITO film layer has a deposition thickness of 20nm-200nm. The patterned ITO layer completely covers the SiO2 insulating filling layer inside the reflective bowl and fits perfectly with the curved surface contour.

5. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S4, the thin film encapsulation layer is a stacked structure of Al2O3 and SiN, wherein the thickness of the Al2O3 layer is 0.1 μm and the thickness of the SiN layer is 1.9 μm.

6. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, The etching processes in S2, S3, and S6 are all dry etching processes, and all photolithography patterning processes use spin-coated photoresist, followed by pre-baking, development, and post-baking to complete the pattern definition.

7. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S6, the MicroLens microlens is made of any one of SiO2, SiN or PI, and its curvature parameters are adapted to the curvature of the parabolic reflector bowl below.

8. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S6, the MicroLens microlens array is arranged in a regular pattern, and the geometric center of each microlens is coaxially aligned with the geometric center of the corresponding reflector bowl below.

9. The method for fabricating a high light-output efficiency Micro-OLED structure according to claim 1, characterized in that, In S4, the light-emitting surface of the organic light-emitting layer faces the thin film encapsulation layer and the subsequent optical layer. The large-angle scattered light emitted by it is focused into small-angle emitted light by the parabolic reflector bowl, and then vertically emitted after being focused twice by the microlens array above.

10. The method for fabricating a high light-output efficiency Micro-OLED structure according to any one of claims 1-9, characterized in that, The fabricated Micro-OLED structure, from bottom to top, consists of: a CMOS substrate, a SiO2 / SiN bilayer dielectric layer, a parabolic reflective bowl anode structure, a pixel definition layer, an organic light-emitting layer, an Al2O3 / SiN stacked encapsulation layer, a CF color filter layer, a TopOC planarization layer, and a MicroLens microlens array. The parabolic reflective bowl anode structure and the MicroLens microlens array work together to achieve secondary light focusing, reduce light scattering loss, and improve the device's light extraction efficiency and peak brightness.

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