Multi-color miniature light emitting diode light emitting structure capable of resisting CMP quenching and preparation method of multi-color miniature light emitting diode light emitting structure

Abstract

The invention relates to the technical field of micro light-emitting diodes, and discloses a CMP quenching resistant multi-color micro light-emitting diode light-emitting structure and a preparation method, the CMP quenching resistant multi-color micro light-emitting diode light-emitting structure comprises a substrate, the substrate is provided with a basic light source pixel unit array and a transparent photoresist pattern layer, and the transparent photoresist pattern layer is arranged on the substrate. The transparent photoresist pattern layer is used for filling a gap area between adjacent basic light source pixel units, and is used for providing a flat supporting surface for subsequent chemical mechanical polishing (CMP) without bearing a shading function. According to the invention, the quantum dots are coated by the inorganic-organic shell layer, so that the influence of a CMP polishing solution and mechanical grinding can be isolated, the light conversion efficiency and stability of multi-color display are ensured, the transparent photoresist focuses on filling gaps and supporting CMP, and the thickness uniformity of the quantum dot filter layer is improved by optimizing the filling structure and thickness and avoiding the collapse of a film layer in the CMP process.

Description

Technical Field

[0001] This invention relates to the field of micro light-emitting diode display technology, specifically to a light-emitting structure and fabrication method of a multicolor micro light-emitting diode resistant to CMP quenching. Background Technology

[0002] MicroLED (micro-light-emitting diode) display technology has become the mainstream direction of next-generation display technology due to its core advantages such as high brightness, high contrast, low power consumption and long life. It is widely used in flexible displays, automotive displays, ultra-large splicing screens and other fields. Among them, red and green dual-color MicroLED can meet the basic color display requirements, while red, blue and green tri-color MicroLED can achieve full-color display. Both rely on quantum dot (red / green) materials to achieve the conversion of light into specific colors. For example, red quantum dots convert green / blue light into red light, and green quantum dots convert blue light into green light.

[0003] However, existing multicolor micro LED light-emitting structures designed to resist CMP quenching still have limitations. First, the quantum dot CMP quenching problem is prominent across various scenarios. Whether it's red quantum dots in a red-green dual-color system or red and green quantum dots in a red-blue-green tri-color system, they are directly exposed to polishing fluid and mechanical abrasion forces during the CMP process. This leads to easy ligand detachment from the quantum dot surface and damage to the crystal structure, resulting in quenching of light-emitting performance and severely impacting light conversion efficiency and display stability. Second, the functional positioning of transparent photoresists is ambiguous, and CMP support is insufficient. In traditional processes, transparent photoresists must both fill gaps and provide light shielding and anti-crosstalk functions. However, their high optical transmittance cannot achieve effective light shielding. Furthermore, because the filling structure has not been optimized for CMP processes, film defects are prone to occur during CMP. Issues such as layer collapse and uneven thickness further affect the uniformity of the quantum dot filter layer. Thirdly, the compatibility of the adhesive is limited and the structural stability is poor: In traditional processes, quantum dots need to be directly dispersed in the adhesive, which must simultaneously consider the dispersion of quantum dots, the compatibility of CMP process, and the tolerance of subsequent coating, resulting in a narrow range of adhesive choices. Moreover, traditional adhesives are prone to structural damage and performance degradation under the pressure of CMP polishing and the ion bombardment of subsequent coating, which cannot meet the long-term stable display requirements of multi-color MicroLEDs. Fourthly, volatile substances accelerate the aging of quantum dots. The volatile components in the adhesive and the volatile substances remaining after CMP cleaning will continuously corrode the red / green quantum dots, accelerate the aging of quantum dots, and shorten the service life of red-green dual-color and red-blue-green tri-color MicroLEDs. Summary of the Invention

[0004] This invention provides a light-emitting structure and fabrication method for a multicolor micro light-emitting diode resistant to CMP quenching, which has the advantages of high light conversion efficiency and stability for multicolor display, high structural stability, and long service life.

[0005] This invention provides the following technical solution: a CMP-resistant multicolor micro-light-emitting diode light-emitting structure and its fabrication method, wherein the CMP-resistant multicolor micro-light-emitting diode light-emitting structure comprises:

[0006] A substrate on which a basic light source pixel unit array is disposed;

[0007] A transparent photoresist pattern layer is used to fill the gap area between adjacent base light source pixel units, providing a flat support surface for subsequent chemical mechanical polishing (CMP) without undertaking a light-shielding function.

[0008] An encapsulated quantum dot filter layer, comprising a quantum dot core, a protective shell, and an anti-CMP adhesive, is applied to the surface of a MicroLED pixel unit and the surface of a transparent photoresist pattern layer.

[0009] This invention also provides a method for fabricating a multicolor micro light-emitting diode light-emitting structure resistant to CMP quenching, comprising the following steps:

[0010] S1. Fabricate a basic light source pixel unit array on the substrate, and select green MicroLED or blue MicroLED according to the target structure;

[0011] S2. Spin-coat transparent photoresist onto the basic light source pixel unit array and the substrate surface, and form a transparent photoresist pattern layer that only fills the pixel gaps through a patterning process.

[0012] S3. Prepare coated quantum dots and mix them with anti-CMP adhesive to obtain coated quantum dot anti-CMP adhesive;

[0013] S4. The encapsulated quantum dot anti-CMP adhesive is applied to the surface of the basic light source pixel unit to form an initial film layer;

[0014] S5. Using the surface of the transparent photoresist pattern layer as the endpoint detection benchmark, perform chemical mechanical polishing (CMP) treatment to make the surface of the encapsulated quantum dot filter layer and the transparent photoresist pattern layer have the same height.

[0015] S6. Dry the structure to remove glue and volatile substances introduced during the cleaning process;

[0016] S7. Perform final curing to obtain a complete multicolor micro light-emitting diode light-emitting structure.

[0017] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro-light-emitting diode light-emitting structure described in this invention, it further includes:

[0018] A transparent photoresist is coated on the surface of the substrate and the pixel unit of the base light source using a spin coating method. The spin coating speed and spin coating time are controlled to ensure that the transparent photoresist completely fills the gap area between adjacent pixel units, forming a photoresist film with a thickness of 1-3 micrometers.

[0019] If SU-8 photoresist is used, pre-baking, exposure, post-baking, and development are required.

[0020] If the photoresist is polyimide transparent, it is directly cured at high temperature to form a dense transparent photoresist pattern layer that fills only the pixel gaps, providing stable support for subsequent CMP.

[0021] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure of the present invention, wherein: S3 further includes:

[0022] Quantum dot cores are dispersed in a solvent, a shell precursor is added, and after stirring and reaction, densely coated quantum dots are obtained by centrifugation.

[0023] The quantum dot core is placed in an atomic layer deposition reaction chamber, and a shell precursor and a reaction gas are introduced. Deposition is carried out at 80-150℃ for 50-500 cycles, and the shell thickness is controlled to be 5-50nm to obtain a highly dense coated quantum dot.

[0024] The coated quantum dots are mixed with the main resin, dispersant, and curing agent of the anti-CMP adhesive in a certain mass ratio, stirred under inert gas protection, and then ultrasonically dispersed, filtered through a filter membrane to remove agglomerated particles, to obtain a uniformly dispersed coated quantum dot anti-CMP adhesive.

[0025] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro-light-emitting diode light-emitting structure described in this invention, it further includes:

[0026] Red pixel area filling: The first mask spin coating is used to precisely fill the pre-set red quantum dot anti-CMP adhesive into the preset red pixel area. The mask opening is perfectly matched with the red pixel area. The spin coating speed and time are controlled to form the initial film layer of red quantum dot adhesive.

[0027] After filling the initial film layer with red quantum dot adhesive, place it in an oven for pre-curing to enhance film adhesion.

[0028] Fill the green pixel area, change the mask, and fill the preset green pixel area with the encapsulated green quantum dot anti-CMP adhesive. The spin coating parameters and pre-curing conditions are the same as those for the red pixel area.

[0029] The blue pixel area is reserved to ensure that the blue MicroLED light source can emit light directly.

[0030] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro-light-emitting diode light-emitting structure described in this invention, it further includes:

[0031] Using the surface of the transparent photoresist pattern layer as a reference, the red and green quantum dot adhesive film layers are subjected to overall CMP treatment, with polishing parameters consistent with the red and green dual-color structure.

[0032] During the polishing process, the thickness of the film layer in the red and green pixel areas is monitored to ensure that both are highly consistent with the transparent photoresist pattern layer. At the same time, any residual adhesive in the blue pixel area is removed to ensure pure light emission from the blue light source.

[0033] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro-light-emitting diode light-emitting structure described in this invention, it further includes:

[0034] The drying process includes vacuum drying or freeze drying;

[0035] The vacuum drying process includes placing the substrate in a vacuum drying chamber and accelerating the volatilization of volatile substances through a vacuum environment.

[0036] The freeze-drying process includes first placing the substrate in a freezer to allow volatile substances to condense into a solid state;

[0037] Then, it is transferred to a freeze dryer for sublimation drying to avoid secondary erosion of the quantum dots by liquid volatiles.

[0038] As an optional embodiment of the method for fabricating the CMP-resistant multicolor micro-light-emitting diode light-emitting structure described in this invention, it further includes:

[0039] In the red-green dual-color structure, step S4 uses spin coating to cover the surface of all green MicroLED pixel units with the encapsulated red quantum dot anti-CMP adhesive.

[0040] In the red, blue and green three-color structure, step S4 uses mask spin coating or inkjet printing to selectively fill the corresponding red and green quantum dot anti-CMP adhesive into the corresponding red and green pixel areas, while the blue pixel areas remain exposed.

[0041] The present invention has the following beneficial effects:

[0042] 1. The light-emitting structure of this multicolor micro LED, which resists CMP quenching, uses an inorganic or organic shell to coat quantum dots, which can isolate the effects of CMP polishing fluid and mechanical grinding, thus ensuring the light conversion efficiency and stability of the multicolor display.

[0043] 2. The light-emitting structure of this multicolor micro LED that resists CMP quenching uses transparent photoresist to fill gaps and support CMP. By optimizing the filling structure and thickness, film collapse during CMP is avoided, thus improving the uniformity of quantum dot filter layer thickness.

[0044] 3. The light-emitting structure of this multicolor micro LED with anti-CMP quenching eliminates the dependence of the adhesive on the dispersion of quantum dots, and allows the selection of high-hardness anti-CMP adhesive, making the quantum dot filter layer less prone to damage during the CMP process and less prone to degradation under subsequent ion bombardment during coating, thereby achieving structural stability.

[0045] 4. The light-emitting structure of this multi-color micro LED, which is resistant to CMP quenching, can completely remove volatile substances through vacuum / freeze-drying process, avoiding long-term corrosion of quantum dots. This extends the lifespan of red-green dual-color MicroLEDs and red-blue-green tri-color MicroLEDs, and effectively avoids color drift problems.

[0046] 5. The light-emitting structure of this CMP-resistant multicolor micro LED can be flexibly switched between red-green dual-color and red-blue-green tri-color structures by adjusting the quantum dot type and filling area, without the need for additional complex equipment; the process is based on traditional spin-coating CMP and is easily compatible with existing MicroLED production lines, meeting the needs of large-scale production. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the overall architecture of the present invention.

[0048] Figure 2 This is a schematic diagram of the overall preparation process of the present invention.

[0049] Figure 3 This is a schematic diagram of the overall structure of the present invention.

[0050] Figure 4 This is a structural diagram of the quantum dot coating of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] Please see Figures 1-4 Furthermore, a multicolor micro light-emitting diode light-emitting structure resistant to CMP quenching is disclosed, comprising:

[0054] A substrate on which a basic light source pixel unit array is disposed;

[0055] A transparent photoresist pattern layer is used to fill the gap area between adjacent base light source pixel units, providing a flat support surface for subsequent chemical mechanical polishing (CMP) without serving a light-shielding function.

[0056] The encapsulated quantum dot filter layer includes a quantum dot core, a protective shell, and an anti-CMP adhesive. The encapsulated quantum dot filter layer is applied to the surface of the MicroLED pixel unit and the surface of the transparent photoresist pattern layer.

[0057] The substrate is made of sapphire or glass, with a thickness of 0.3-1mm and an optical transmittance of ≥90%, and is used to provide stable support for each functional layer and ensure the flatness of the overall structure.

[0058] Basic light source pixel unit:

[0059] Red and green dual-color, green MicroLED (wavelength 520-535nm);

[0060] Red, blue and green colors, blue MicroLED (wavelength 445-455nm), pixel pitch 5-20 micrometers;

[0061] The transparent photoresist pattern layer uses SU-8 transparent photoresist or polyimide transparent photoresist, with a thickness of 1-3 micrometers and a transmittance of ≥95% in the 400-700nm wavelength band. It fills the gaps between adjacent basic light source pixel units to fill the pixel gaps, providing a flat and stable support surface for the CMP process and preventing film collapse; it does not perform the function of light shielding, but only focuses on structural support.

[0062] The encapsulated quantum dot filter layer has a thickness of 0.5-2 micrometers and is at the same height as the transparent photoresist pattern layer (height difference ≤ ±0.1 micrometers). It is composed of a quantum dot core, a protective shell, and anti-CMP adhesive.

[0063] Red-green dual-color: Red quantum dots convert green light into red light;

[0064] Red, blue, and green: Red and green quantum dots convert blue light into red and green light respectively to achieve the target color display.

[0065] Specifically, the encapsulated quantum dot filter layer:

[0066] The quantum dot core uses CdSe / ZnS or InP / ZnS for red quantum dots (particle size 3-8nm, red light wavelength 620-635nm, quantum yield ≥90%), and CdZnSe / ZnS or InGaP / ZnS for green quantum dots (particle size 2-5nm, green light wavelength 520-535nm, quantum yield ≥90%), adapting to the light conversion needs of different scenarios.

[0067] The protective shell is made of inorganic oxides (Al2O3, SiO2, TiO2, thickness 5-50nm) or organic polymers (polymethyl methacrylate, polysiloxane, thickness 10-100nm), with a shell density of ≥95%, which can effectively isolate the quantum dot core from the erosion of CMP polishing slurry and mechanical grinding.

[0068] This CMP-resistant adhesive is composed of main resins (epoxy resin, polyurethane resin, polyimide resin), dispersants (BYK-163, Tego Dispers 750W), and curing agents (diaminodiphenylmethane, isocyanate). It has a Shore hardness of D60-D85 and a glass transition temperature (Tg) ≥150℃. It has resistance to mechanical abrasion and ion bombardment, and does not require excessive consideration of quantum dot dispersibility, thus broadening the range of adhesive choices.

[0069] Transparent photoresist pattern layer:

[0070] It fills only the gaps between adjacent base light source pixel units, forming a regular pixel-gap-pixel structure. Its thickness matches the endpoint detection benchmark of the subsequent CMP process, ensuring the uniformity of the height of the coated quantum dot filter layer after CMP.

[0071] Example 2

[0072] This invention also provides a method for fabricating a multicolor micro light-emitting diode light-emitting structure resistant to CMP quenching, comprising the following steps:

[0073] Includes the following steps:

[0074] S1. Fabricate a basic light source pixel unit array;

[0075] The type of basic light source is selected based on the target structure, specifically:

[0076] Red-green dual-color structure: Select sapphire / glass substrate, use metal-organic chemical vapor deposition (MOCVD) process to grow gallium nitride-based epitaxial layer (doped with indium gallium nitride to achieve green light emission), photolithography etching (forming pixel pattern, pixel pitch 5-20 micrometers) and electrode fabrication (evaporation of Cr / Au or ITO electrodes) to obtain matrix-arranged green MicroLED pixel units.

[0077] Red, blue and green three-color structure: Select sapphire / glass substrate, use MOCVD process to grow gallium nitride-based epitaxial layer (undoped or low doped indium to achieve blue light emission), and after photolithography etching and electrode preparation, obtain matrix-arranged blue MicroLED pixel units (pixel pitch 5-20 micrometers).

[0078] S2. Coat a transparent photoresist layer and form a transparent photoresist pattern layer;

[0079] Spin coating: A transparent photoresist (SU-8 or polyimide) is coated onto the substrate and the surface of the base light source pixel unit using a spin coating method. The spin coating speed is controlled at 2000-5000 rpm and the time is 30-60 seconds to ensure that the transparent photoresist completely fills the gap area between adjacent pixel units, forming a photoresist film with a thickness of 1-3 micrometers.

[0080] Patterning and curing: If using SU-8 photoresist, pre-baking (95℃, 30 minutes), exposure (for gap-filling areas, exposure dose 80-120mJ / cm²), post-baking (120℃, 20 minutes), and development (removing excess photoresist from the pixel unit surface) are required; if using polyimide transparent photoresist, high-temperature curing (200-250℃, 1 hour) is performed directly, ultimately forming a dense transparent photoresist pattern layer that only fills the pixel gaps, providing stable support for subsequent CMP.

[0081] S3. Preparation of coated quantum dot anti-CMP adhesive;

[0082] Based on the target structural requirements, red or red / green coated quantum dots are prepared and then composited with CMP-resistant adhesive. Specific steps are as follows:

[0083] Quantum dot coating (wet coating / ALD method):

[0084] Wet coating: The quantum dot cores (red / green) are dispersed in a solvent (toluene, chloroform), and a shell precursor (trimethylaluminum for Al2O3, tetraethyl orthosilicate for SiO2) is added. The mixture is stirred at 50-100℃ for 2-8 hours, centrifuged (8000-10000 rpm, 10 minutes), washed three times with ethanol, and vacuum dried (60-80℃, 2 hours) to obtain densely coated quantum dots.

[0085] ALD method: The quantum dot core is placed in the atomic layer deposition (ALD) reaction chamber, and the shell precursor and reaction gas (such as water and oxygen) are introduced. 50-500 cycles are deposited at 80-150℃ (0.1-0.2 nm shell is grown in each cycle). The shell thickness is controlled to be 5-50 nm to obtain highly dense coated quantum dots.

[0086] Adhesive lamination: The coated quantum dots (red / green) are mixed with the main resin, dispersant, and curing agent of the anti-CMP adhesive at a mass ratio of 10-30:50-80:1-5:2-8. The mixture is stirred for 2-4 hours (500-800 rpm) under inert gas (nitrogen, argon) protection. After ultrasonic dispersion (300-500W, 30-60 minutes) and filtration through a 0.22μm filter membrane, agglomerated particles are removed to obtain a uniformly dispersed coated quantum dot anti-CMP adhesive (red / green).

[0087] The red-green bicolor structure includes S4-S5:

[0088] S4. Preparation of coated red quantum dot filter layer by spin coating combined with CMP

[0089] Spin coating and filling: The encapsulated red quantum dot anti-CMP adhesive is uniformly coated onto the surface of the green MicroLED pixel unit and the surface of the transparent photoresist pattern layer using a spin coating device. The spin coating speed is controlled at 3000-5000 rpm and the time is 30-60 seconds to form an initial film layer (1-4 micrometers thicker than the transparent photoresist pattern layer), ensuring that the adhesive completely covers the green pixel unit without gaps.

[0090] Pre-curing: Place the spin-coated substrate in an oven and pre-cur it at 80-120℃ for 30-60 minutes to allow the adhesive to initially cure, enhance the mechanical strength of the film layer, and prevent the adhesive from peeling off during the subsequent CMP process.

[0091] CMP Processing: The surface of the transparent photoresist pattern layer is used as the endpoint for inspection, and polishing is performed using chemical mechanical polishing (CMP) equipment. Polishing parameters are controlled as follows: polishing pressure 10-30 kPa, polishing speed 50-100 rpm, and a neutral silica polishing solution (pH=6.5-7.5, to avoid corroding the quantum dot coating layer) is used. The film thickness is monitored in real time using a laser interferometer to ensure that the height of the coated red quantum dot filter layer and the transparent photoresist pattern layer is consistent after polishing (height difference ≤ ±0.1 micrometers).

[0092] The red, blue, and green tricolor structure includes S4'-S5':

[0093] S4', Spin-on coating type red / green quantum dot adhesive;

[0094] Red pixel area filling: Using a mask spin coating or inkjet printing method, the encapsulated red quantum dot anti-CMP adhesive is precisely filled into the preset red pixel area (the surface of the blue MicroLED pixel unit). The mask opening is perfectly matched with the red pixel area. The spin coating speed is controlled at 3000-4000 rpm for 30 seconds to form the initial red quantum dot adhesive film layer (1-2 micrometers thicker than the transparent photoresist pattern layer). After filling, it is placed in an 80-100℃ oven for pre-curing for 30 minutes to enhance the adhesion of the film layer.

[0095] Green pixel area filling: Replace the mask (with the opening matching the green pixel area), and use the same process to fill the pre-set green pixel area (the surface of the blue MicroLED pixel unit) with the encapsulated green quantum dot anti-CMP adhesive. The spin coating parameters and pre-curing conditions are the same as those for the red pixel area. The blue pixel area is reserved (without any quantum dot adhesive) to ensure that the blue MicroLED light source can emit light directly.

[0096] S5', Overall CMP Processing;

[0097] Using the surface of the transparent photoresist pattern layer as a reference, the red / green quantum dot adhesive film layer was subjected to overall CMP treatment, with polishing parameters consistent with the red-green dual-color structure (polishing pressure 10-30 kPa, rotation speed 50-100 rpm, neutral polishing slurry). During the polishing process, the film thickness in the red and green pixel areas was closely monitored to ensure that both were highly consistent with the transparent photoresist pattern layer. At the same time, any residual adhesive in the blue pixel areas was removed to ensure pure light emission from the blue light source.

[0098] S6 / S6', drying process to remove volatile substances;

[0099] Vacuum drying or freeze drying methods are used to thoroughly remove volatile components inherent in the adhesive and residual volatiles introduced during the CMP cleaning process. Specific process details are as follows:

[0100] Vacuum drying: Place the substrate in a vacuum drying oven, set the vacuum level to ≤10Pa, the temperature to 60-100℃, and the drying time to 2-6 hours. The vacuum environment accelerates the volatilization of volatile substances.

[0101] Freeze-drying: First, place the substrate in a freezer at -40 to -20°C for 1-2 hours to allow volatile substances to condense into a solid state; then transfer it to a freeze dryer, set the vacuum degree to ≤10Pa, and the temperature to 20-40°C for sublimation drying for 4-8 hours to avoid secondary erosion of the quantum dots by liquid volatile substances.

[0102] S7 / S7', final curing;

[0103] The dried substrate is placed in a curing oven and cured at 150-200℃ for 1-3 hours (180℃ / 2 hours for epoxy resin, 200℃ / 1.5 hours for polyimide) to fully cure the encapsulated quantum dot anti-CMP adhesive, forming a quantum dot filter layer with stable structure and excellent optical performance, and finally obtaining a red-green dual-color / red-blue-green tri-color micro light-emitting diode light-emitting structure.

[0104] Example 3

[0105] This embodiment is an improvement on embodiment 2. Specifically, the red-green dual-color structure includes:

[0106] The substrate is made of sapphire, with a thickness of 0.5 mm and an optical transmittance of 92%.

[0107] The base light source uses green MicroLED pixel units with a wavelength of 525nm and a pixel pitch of 10 micrometers;

[0108] The transparent photoresist pattern layer is made of SU-8 photoresist, with a thickness of 2 micrometers and a transmittance of 96% in the 400-700nm wavelength band;

[0109] The encapsulated red quantum dot filter layer is 1.5 micrometers thick, with a quantum dot core of InP / ZnS (particle size 5nm, wavelength 625nm), a protective shell of Al2O3 (thickness 20nm), and an anti-CMP adhesive of epoxy resin (Shore hardness D75, Tg=160℃).

[0110] The preparation steps include:

[0111] A1. A gallium nitride-based green epitaxial layer is grown on a sapphire substrate using MOCVD technology. Pixel patterns are formed by photolithography and etching, and Cr / Au electrodes are deposited by vapor deposition to obtain a green MicroLED array.

[0112] A2. Spin-coat SU-8 photoresist (3000 rpm, 45 seconds), pre-baking (95℃ / 30 minutes), exposure (100 mJ / cm²), post-baking (120℃ / 20 minutes), and development to form a transparent photoresist pattern layer filling the pixel gaps.

[0113] A3. Al2O3-coated InP / ZnS quantum dots were prepared by ALD method. They were mixed with epoxy resin, BYK-163 and diaminodiphenylmethane at a mass ratio of 20:65:3:5. The mixture was stirred for 3 hours under inert gas protection, ultrasonically dispersed for 45 minutes, and filtered to obtain red quantum dot adhesive.

[0114] A4. Spin-coat red quantum dot adhesive (4000 rpm, 40 seconds, initial thickness 5 micrometers), pre-cur at 100℃ for 45 minutes; using the transparent photoresist pattern layer as a reference, perform CMP treatment (20 kPa pressure, 80 rpm rotation speed, neutral polishing fluid) until highly uniform.

[0115] A5. Vacuum drying (5Pa, 80℃, 4 hours) to remove volatile substances.

[0116] A6, cured at 180℃ for 2 hours, yielded a red-green dual-color structure.

[0117] Example 4

[0118] This embodiment is an improvement on embodiment 2. Specifically, the red, blue, and green tricolor structure includes:

[0119] The substrate is made of glass, with a thickness of 0.7 mm and an optical transmittance of 91%.

[0120] The base light source uses blue MicroLED pixel units with a wavelength of 450nm and a pixel pitch of 8 micrometers.

[0121] The transparent photoresist pattern layer is made of polyimide transparent photoresist, with a thickness of 1.5 micrometers and a transmittance of 95% in the 400-700nm wavelength band;

[0122] The encapsulated quantum dot filter layer uses a red filter layer (CdSe / ZnS core, SiO2 shell, 1.2 μm thickness, 630 nm wavelength); a green filter layer (CdZnSe / ZnS core, polysiloxane shell, 1.2 μm thickness, 530 nm wavelength); and the anti-CMP adhesive is polyimide (Shore hardness D80, Tg=180℃).

[0123] B1. A gallium nitride-based blue epitaxial layer is grown on a glass substrate using MOCVD technology. After photolithography etching and ITO electrode deposition, a blue MicroLED array is obtained.

[0124] B2. Spin-coat polyimide transparent photoresist (4000 rpm, 30 seconds), cure at 220°C for 1 hour to form a transparent photoresist pattern layer filling the pixel gaps.

[0125] B3. SiO2-coated CdSe / ZnS quantum dots and polysiloxane-coated CdZnSe / ZnS quantum dots were prepared by wet coating and mixed with polyimide adhesive at a mass ratio of 25:60:3:6 to obtain red / green quantum dot adhesive.

[0126] B4. Spin-coat the mask with red adhesive to the red pixel area (3500 rpm, 30 seconds) and green adhesive to the green pixel area (same parameters as red). Pre-cure at 90°C for 30 minutes.

[0127] B5. Using the transparent photoresist pattern layer as a reference, perform CMP treatment (pressure 15kPa, rotation speed 70rpm, neutral polishing fluid) until the red / green filter layer height is consistent, and remove residual adhesive in the blue pixel area.

[0128] B6. Freeze-drying (freeze at -30℃ for 1.5 hours, 5 Pa, sublimate at 30℃ for 6 hours).

[0129] B7. After final curing at 200℃ for 1.5 hours, a red, blue and green tricolor structure is obtained.

[0130] This specification also provides a computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the multiple steps described in the above embodiments. If the constituent modules of the above-described electronic device are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0131] This specification also provides a computer program product, including a computer program that, when executed by a processor, implements the multiple steps described in the above embodiments.

[0132] Where there is no conflict, the technical features in this embodiment and implementation scheme can be combined arbitrarily.

[0133] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes multiple computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating multiple available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital versatile discs (DVDs)), or semiconductor media (e.g., solid state disks (SSDs)).

[0134] When implemented through hardware or firmware, the aforementioned method flow is programmed into the hardware circuit to obtain the corresponding hardware circuit structure and achieve the corresponding function. For example, a Programmable Logic Device (PLD) (such as a Field Programmable Gate Array (FPGA)) is such an integrated circuit, whose logic function is determined by the user programming the device. Designers can program a digital system onto a PLD themselves, eliminating the need for chip manufacturers to design and fabricate dedicated integrated circuit chips. Furthermore, nowadays, instead of manually fabricating integrated circuit chips, this programming is mostly implemented using "logic compiler" software, similar to the software compiler used in program development. The original code before compilation must also be written in a specific programming language, called a Hardware Description Language (HDL). There is not just one HDL, but many. Those skilled in the art should understand that by simply performing some logic programming on the method flow using one of the aforementioned hardware description languages ​​and programming it into an integrated circuit, the hardware circuit implementing the logical method flow can be easily obtained.

[0135] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0136] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A light-emitting structure for a multicolor micro light-emitting diode resistant to CMP quenching, characterized in that, include: A substrate on which a basic light source pixel unit array is disposed; A transparent photoresist pattern layer is used to fill the gap area between adjacent base light source pixel units, providing a flat support surface for subsequent chemical mechanical polishing (CMP) without undertaking a light-shielding function. An encapsulated quantum dot filter layer, comprising a quantum dot core, a protective shell, and an anti-CMP adhesive, is applied to the surface of a MicroLED pixel unit and the surface of a transparent photoresist pattern layer.

2. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 1, characterized in that, Includes the following steps: S1. Fabricate a basic light source pixel unit array on the substrate, and select green MicroLED or blue MicroLED according to the target structure; S2. Spin-coat transparent photoresist onto the basic light source pixel unit array and the substrate surface, and form a transparent photoresist pattern layer that only fills the pixel gaps through a patterning process. S3. Prepare coated quantum dots and mix them with anti-CMP adhesive to obtain coated quantum dot anti-CMP adhesive; S4. The encapsulated quantum dot anti-CMP adhesive is applied to the surface of the basic light source pixel unit to form an initial film layer; S5. Using the surface of the transparent photoresist pattern layer as the endpoint detection benchmark, perform chemical mechanical polishing (CMP) treatment to make the surface of the encapsulated quantum dot filter layer and the transparent photoresist pattern layer have the same height. S6. Dry the structure to remove glue and volatile substances introduced during the cleaning process; S7. Perform final curing to obtain a complete multicolor micro light-emitting diode light-emitting structure.

3. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 2, characterized in that, S2 also includes: A transparent photoresist is coated on the surface of the substrate and the pixel unit of the base light source using a spin coating method. The spin coating speed and spin coating time are controlled to ensure that the transparent photoresist completely fills the gap area between adjacent pixel units, forming a photoresist film with a thickness of 1-3 micrometers. If SU-8 photoresist is used, pre-baking, exposure, post-baking, and development are required. If the photoresist is polyimide transparent, it is directly cured at high temperature to form a dense transparent photoresist pattern layer that fills only the pixel gaps, providing stable support for subsequent CMP.

4. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 3, characterized in that, S3 further includes: Quantum dot cores are dispersed in a solvent, a shell precursor is added, and after stirring and reaction, densely coated quantum dots are obtained by centrifugation. The quantum dot core is placed in an atomic layer deposition reaction chamber, and a shell precursor and a reaction gas are introduced. Deposition is carried out at 80-150℃ for 50-500 cycles, and the shell thickness is controlled to be 5-50nm to obtain a highly dense coated quantum dot. The coated quantum dots are mixed with the main resin, dispersant, and curing agent of the anti-CMP adhesive in a certain mass ratio, stirred under inert gas protection, and then ultrasonically dispersed, filtered through a filter membrane to remove agglomerated particles, to obtain a uniformly dispersed coated quantum dot anti-CMP adhesive.

5. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 4, characterized in that, S4 further includes: Red pixel area filling: The first mask spin coating is used to precisely fill the pre-set red quantum dot anti-CMP adhesive into the preset red pixel area. The mask opening is perfectly matched with the red pixel area. The spin coating speed and time are controlled to form the initial film layer of red quantum dot adhesive. After filling the initial film layer with red quantum dot adhesive, place it in an oven for pre-curing to enhance film adhesion. Fill the green pixel area, change the mask, and fill the preset green pixel area with the encapsulated green quantum dot anti-CMP adhesive. The spin coating parameters and pre-curing conditions are the same as those for the red pixel area. The blue pixel area is reserved to ensure that the blue MicroLED light source can emit light directly.

6. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 5, characterized in that, The S5 also includes: Using the surface of the transparent photoresist pattern layer as a reference, the red and green quantum dot adhesive film layers are subjected to overall CMP treatment, with polishing parameters consistent with the red and green dual-color structure. During the polishing process, the thickness of the film layer in the red and green pixel areas is monitored to ensure that both are highly consistent with the transparent photoresist pattern layer. At the same time, any residual adhesive in the blue pixel area is removed to ensure pure light emission from the blue light source.

7. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 6, characterized in that, S6 further includes: The drying process includes vacuum drying or freeze drying; The vacuum drying process includes placing the substrate in a vacuum drying chamber and accelerating the volatilization of volatile substances through a vacuum environment. The freeze-drying process includes first placing the substrate in a freezer to allow volatile substances to condense into a solid state; Then, it is transferred to a freeze dryer for sublimation drying to avoid secondary erosion of the quantum dots by liquid volatiles.

8. The method for fabricating the CMP-resistant multicolor micro light-emitting diode light-emitting structure according to claim 7, characterized in that, Also includes: In the red-green dual-color structure, step S4 uses spin coating to cover the surface of all green MicroLED pixel units with the encapsulated red quantum dot anti-CMP adhesive. In the red, blue and green three-color structure, step S4 uses mask spin coating or inkjet printing to selectively fill the corresponding red and green quantum dot anti-CMP adhesive into the corresponding red and green pixel areas, while the blue pixel areas remain exposed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 2-8.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 2-8.

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