Passivation process for Micro LED light-emitting module with vertical structure

Abstract

The invention provides a passivation process for a Micro LED light-emitting module with a vertical structure, and the process comprises the following steps: preparing GaN-based Micro LED units which are arranged in an array on a substrate, and each GaN-based Micro LED unit sequentially comprises a P electrode and a GaN table top from bottom to top; depositing an inorganic passive film, wherein the inorganic passive film covers the GaN table top, the side walls of the GaN-based Micro LED units and the grooves between the GaN-based Micro LED units; preparing an organic matter on the surface of the inorganic passivation film, wherein the organic matter fills and levels up the grooves between the GaN-based Micro LED units, and the surface is flat; etching the organic matter on the whole surface to expose the inorganic passivation film on the GaN table surface; etching the inorganic passivation film to expose the GaN table surface; and preparing a patterned N electrode on the exposed GaN mesa. The inorganic passive film technology and the organic matter planarization technology are combined together, the electric leakage risk of the Micro LED light-emitting module is reduced, and the device yield and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor display devices, and particularly to a passivation process for vertical structure Micro LED light-emitting modules. Background Art

[0002] In recent years, a new display technology using micron-scale LEDs (also known as Micro LEDs or μLEDs) as display units has gradually become a hot spot in the display field. Compared with organic LEDs (OLEDs), Micro LEDs have advantages such as high brightness, wide color gamut, high resolution, high contrast, low energy consumption, and high stability, and can be applied in various fields such as VR / AR / XR displays, visible light communication, and medical treatment.

[0003] In the research of Micro LEDs, Micro LEDs based on GaN-based materials have been widely studied because of their obvious advantages in comprehensive performance compared with other LED materials. Currently, the GaN-based Micro LED light-emitting modules applied to near-eye displays are composed of pixel units arranged in an array, and the pixel size of the pixel units is usually less than 10 μm, among which the vertical structure is one of the mainstream structures. In the vertical structure GaN-based Micro LED pixel unit, its structural feature is that an N electrode and a P electrode are respectively arranged above and below the GaN mesa. In this type of structure, it is crucial to ensure effective electrical isolation between the N electrode and the P electrode.

[0004] However, in the actual process of fabricating GaN-based Micro LED light-emitting modules, due to the small pixel size, the situation where the GaN mesa of some pixel units falls off often occurs (as shown in the attachment). Figure 1 This phenomenon will cause the N electrode above the GaN mesa falling-off part to be directly connected to the P electrode below when fabricating the N electrode subsequently, resulting in the leakage problem of the Micro LED light-emitting module. In addition, due to the certain height of the mesa of the GaN-based pixel unit, relatively deep grooves exist between the pixel units, which has an adverse impact on the subsequent process. Summary of the Invention

[0005] To solve the above problems, the present invention provides a passivation process for vertical structure Micro LED light-emitting modules, which combines the inorganic passivation film technology and the organic planarization technology, effectively reducing the leakage risk of the vertical structure Micro LED light-emitting module and improving the device yield and reliability.

[0006] The technical solution of the present invention is as follows: A passivation process for vertical structure Micro LED light-emitting modules, comprising the following steps: S01. Prepare GaN-based Micro LED units arranged in an array on a substrate. The GaN-based Micro LED units sequentially include a P electrode and a GaN mesa from bottom to top; S02. Deposit an inorganic passivation film, which covers the GaN mesa, the sidewalls of the GaN-based Micro LED units, and the trenches between the GaN-based Micro LED units; S03. Prepare an organic material on the surface of the inorganic passivation film. The organic material fills the trenches between the GaN-based Micro LED units and has a flat surface; S04. Etch the organic material over the entire surface to expose the inorganic passivation film on the GaN mesa; S05. Etch the inorganic passivation film to expose the GaN mesa; S06. Prepare a patterned N electrode on the exposed GaN mesa.

[0007] Optionally, the material of the inorganic passivation film is one or a combination of SiN x , SiO2, and Al2O3, and the thickness range of the inorganic passivation film is 100 nm - 300 nm.

[0008] Optionally, the material of the inorganic passivation film is SiN x / SiO2 stack, the thickness range of SiN x is 20 nm - 50 nm, and the thickness range of SiO2 is 70 nm - 280 nm.

[0009] Optionally, the material of the organic material is one of SU-8, polyimide, benzocyclobutene, SOG glass, and silane compounds, and the thickness range of the organic material is 1.6 μm - 2.0 μm.

[0010] Optionally, the method for etching the organic material over the entire surface in step S04 is ICP etching, and the etching gas is one or several of O2, CF4, and CH4.

[0011] Optionally, the specific steps for etching the inorganic passivation film in step S05 are: S051. Coat a photoresist over the entire surface, perform photolithography on the photoresist to expose the inorganic passivation film on the GaN mesa; S052. Use the remaining photoresist as an etching mask, etch the inorganic passivation film by ICP to expose the GaN mesa, and remove the remaining photoresist.

[0012] Optionally, the etching gas for ICP etching in step S052 is one or several of CF4, CH4, Cl2, and BCl3.

[0013] Optionally, the specific steps for preparing the organic material in step S03 are: S031. Coat an organic material on the surface of the inorganic passivation film. The organic material fills the grooves between GaN-based Micro LED units and has a flat surface. S032. Cure the organic material to complete the preparation of the organic material.

[0014] Optionally, the method for curing the organic material in step S032 is thermal curing, and the curing temperature is 200°C - 280°C.

[0015] Optionally, the material of the N electrode is one or more of Ti, Cr, Pt, Au, Al, Cu, and ITO, and the thickness range of the N electrode is 100 nm - 400 nm.

[0016] Compared with the prior art, the passivation process provided by the present invention combines the inorganic passivation film technology and the organic material planarization technology. It can not only make full use of the inorganic passivation film to effectively passivate the sidewalls of the GaN mesa, but also make full use of the organic material to play a role in local planarization, thus facilitating the subsequent process. More importantly, if the GaN mesa falls off, the organic material can also fill the area where the GaN mesa falls off, effectively preventing the upper N electrode from directly connecting to the lower P electrode, reducing the leakage risk of the Micro LED light-emitting module, and improving the device yield and reliability. Description of the Drawings

[0017] Figure 1 It is a SEM picture when the GaN mesa of some pixel units in the vertical structure Micro LED light-emitting module falls off.

[0018] Figure 2 It is a schematic cross-sectional structure diagram after depositing the inorganic passivation film in the embodiment of the present invention.

[0019] Figure 3 It is a schematic cross-sectional structure diagram after preparing the organic material in the embodiment of the present invention.

[0020] Figure 4 It is a schematic cross-sectional structure diagram after etching the organic material on the whole surface in the embodiment of the present invention.

[0021] Figure 5 It is a schematic cross-sectional structure diagram after lithography to expose the inorganic passivation film on the GaN mesa in the embodiment of the present invention.

[0022] Figure 6 For the embodiment of the present invention to remove Figure 5 The schematic cross-sectional structure diagram of the exposed inorganic passivation film.

[0023] Figure 7 It is a schematic cross-sectional structure diagram after removing the remaining photoresist in the embodiment of the present invention.

[0024] Figure 8Schematic cross-sectional structure diagram after preparing a patterned N electrode in an embodiment of the present invention.

[0025] Figure 9 Schematic cross-sectional structure diagram of an organic matter filling the GaN mesa detachment region when there is GaN mesa detachment in an embodiment of the present invention.

[0026] Figure 10 is Figure 9 Schematic cross-sectional structure diagram after preparing a patterned N electrode in

[0027] Figure 11 Schematic plan view of a vertical structure Micro LED light-emitting module provided in an embodiment of the present invention.

[0028] Figure 12 Schematic cross-sectional structure diagram of a vertical structure Micro LED light-emitting module prepared in a comparative example of the present invention with only an inorganic passivation film deposited. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] An embodiment of the present application provides a passivation process for a vertical structure Micro LED light-emitting module, including the following steps: S01. Prepare GaN-based Micro LED units arranged in an array on a substrate 101. The GaN-based Micro LED units sequentially include a P electrode 102 and a GaN mesa 103 from bottom to top; S02. Deposit an inorganic passivation film 201. The inorganic passivation film 201 covers the GaN mesa 103, the sidewalls of the GaN-based Micro LED units, and the trenches between the GaN-based Micro LED units; S03. Prepare an organic matter 202 on the surface of the inorganic passivation film 201. The organic matter 202 fills the trenches between the GaN-based Micro LED units and has a flat surface; S04. Etch the organic matter 202 over the entire surface to expose the inorganic passivation film on the GaN mesa 103; S05. Etch the inorganic passivation film to expose the GaN mesa 103; S06. Prepare a patterned N electrode 204 on the exposed GaN mesa 103.

[0031] The embodiments of the present application not only effectively passivate the sidewalls of the GaN mesa using an inorganic passivation film, but also can make full use of the organic matter to play a role in local planarization, thus facilitating the subsequent processes. More importantly, the organic matter is etched over the entire surface. In this way, if some GaN mesa falls off, the organic matter can fill these fallen-off areas during the etching of the entire surface, as Figure 9 shown. After the N electrode is subsequently prepared, it will not cause a short circuit between the N electrode and the P electrode, as Figure 10 shown. In addition, the organic matter fills the trenches between the GaN-based MicroLED units, and the etching of the organic matter over the entire surface can also reduce the height difference between the bottom of the N electrode and the upper surface of the GaN mesa, which is beneficial to the subsequent processes.

[0032] In some embodiments, the material of the inorganic passivation film 201 is one or a combination of SiN x , SiO2, and Al2O3. Exemplarily, it is SiN x , Al2O3, SiN x / SiO2, Al2O3 / SiO2, Al2O3, SiN x / SiO2 / SiN x , but not limited thereto; the thickness range of the inorganic passivation film 201 is 100 nm - 300 nm. Exemplarily, it is 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, but not limited thereto. The three materials SiN x , SiO2, and Al2O3 can all passivate the GaN sidewall defects to a certain extent, and at the same time can coat the light-emitting quantum well layer to avoid leakage. In addition, their total thickness must be within the range of 100 nm - 300 nm. If it is too thin, holes are likely to appear, causing the GaN sidewall to be in direct contact with the external environment. If it is too thick, the removal difficulty will increase, and stress problems will also arise.

[0033] In some embodiments, the material of the inorganic passivation film 201 is a SiN x / SiO2 stack. The thickness range of SiN x is 20 nm - 50 nm. Exemplarily, it is 20 nm, 30 nm, 40 nm, 45 nm, 50 nm, but not limited thereto; the thickness range of SiO2 is 100 nm - 280 nm. Exemplarily, it is 100 nm, 150 nm, 200 nm, 250 nm, 280 nm, but not limited thereto. Among them, SiN x has good adhesion to both GaN and metal, so it is used as the inner layer to coat the surface and has a relatively thin thickness because its light transmittance in the visible light range is not high enough; while the main body of the stack is SiO2 because its light transmittance in the visible light range is relatively high, which is more beneficial for light emission.

[0034] In some embodiments, the material of the organic matter 202 is one of SU-8, polyimide, benzocyclobutene, SOG glass, and silane compounds. The thickness range of the organic matter 202 is 1.6 μm - 2.0 μm, and exemplary values are 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, but not limited thereto. The organic matter 202 must be higher than the light-emitting quantum well layer in the GaN mesa by a certain thickness to prevent short-circuiting between the N electrode 204 and the P electrode 102 after the subsequent preparation of the N electrode 204.

[0035] In some embodiments, the method of etching the organic matter 202 over the entire surface in step S04 is ICP etching, and the etching gas is one or more of O2, CF4, and CH4, and exemplary ones are O2, CF4, and CF4 / CH4, but not limited thereto. O2, CF4, and CH4 have no selectivity for etching the organic matter 202, and the etching rate of the organic matter over the entire surface can be adjusted according to the gas flow rate and etching power. Therefore, while exposing the inorganic passivation film on the GaN mesa 103 during the over-the-whole-surface etching, it can also ensure that there is still organic matter in the trench.

[0036] In some embodiments, the specific steps of etching the inorganic passivation film 201 in step S05 are as follows: S051: Coating photoresist over the entire surface, performing photolithography on the photoresist to expose the inorganic passivation film on the GaN mesa; S052: Using the remaining photoresist 203 as an etching mask, etching the inorganic passivation film through ICP to expose the GaN mesa 103, and removing the remaining photoresist. This step is mainly to completely remove the inorganic passivation film on the upper surface of GaN so that the N electrode can form an electrical connection with GaN. At the same time, the photoresist 203 can be used as a mask in step S052 to ensure that the inorganic passivation film and organic matter at other positions are not affected by the ICP etching.

[0037] In some embodiments, the material of the photoresist in step S051 is 5312 positive photoresist or 2106 negative photoresist. Both 5312 positive photoresist and 2106 negative photoresist are a kind of photosensitive photoresist produced by Suzhou Ruihong Electronic Chemicals Co., Ltd., but not limited thereto.

[0038] In some embodiments, the etching gas for ICP etching in step S052 is one or more of CF4, CH4, Cl2, and BCl3, and exemplary ones are CF4, CH4, Cl2, BCl3, CF4 / CH4, Cl2 / BCl3, etc., but not limited thereto. These etching gases can react with the inorganic passivation film to expose the upper surface of GaN.

[0039] In some embodiments, the specific steps of preparing the organic matter 202 in step S03 are as follows: S031. Coating an organic material on the surface of the inorganic passivation film, where the organic material fills the trenches between GaN-based Micro LED units and the surface is flat; S032. Curing the organic material to complete the preparation of the organic material 202. Curing can remove the solvent in the organic material and also promote the cross-linking reaction of the organic material monomers, thereby reducing the fluidity of the organic material and making the organic material firmly adhere to the surface of the inorganic passivation film.

[0040] In some embodiments, the method of curing the organic material in step S032 is thermal curing, and the curing temperature is 200°C - 280°C, for example, 200 o °C, 230 o °C, 260 o °C, 280 o °C, but not limited thereto. The curing equipment is a hot stage, an oven, a vacuum drying oven, etc. The thermal curing of the organic material can significantly improve the mechanical strength of the organic material, and at the same time, the tolerance of the cured organic material to various solutions, high humidity and high temperature environments will also be significantly improved.

[0041] In some embodiments, the material of the N electrode 204 is one or more of Ti, Cr, Pt, Au, Al, Cu, ITO (indium tin oxide), for example, TiCr, Pt, Au, Al, Cu, ITO, Ti / Al, Cr / Au, Cr / PtAu, ITO / Au, ITO / Al, etc., but not limited thereto; the thickness range of the N electrode 204 is 100nm - 400nm, for example, 100nm, 200nm, 300nm, 400nm, but not limited thereto. Among them, metal materials such as Ti, Cr, Pt, Au, Al, Cu have good electrical conductivity, and ITO is a conductive high-transparency thin film. They can all be used as the N electrode to connect with the GaN upper surface, so as to form an electrical connection. In addition, the thickness range of the N electrode 204 should be ensured to be within 100nm - 400nm. If the N electrode is too thin, it is easy to break, and if it is too thick, the cost will increase and the light transmittance will decrease. Example 1

[0042] This example provides a passivation process for a vertical structure Micro LED light-emitting module, and the specific steps are as follows: Step S01. Preparing GaN-based Micro LED units arranged in an array on the substrate 101, and the GaN-based Micro LED units sequentially include a P electrode 102 and a GaN mesa 103 from bottom to top.

[0043] Step S02. Using PECVD to deposit an inorganic passivation film 201 on the periphery and top of the GaN-based Micro LED units, and on the trenches between the GaN-based Micro LED units. The inorganic passivation film 201 is SiNx / SiO2 stack, SiN x The thickness of is 30 nm, and the thickness of SiO2 is 100 nm. The structure after depositing the inorganic passivation film 201 is as Figure 2 shown.

[0044] Step S03: Coating a layer of 2-μm-thick SU-8 glue on the surface of the inorganic passivation film 201. The SU-8 glue fills the trenches between the GaN-based Micro LED units and keeps the surface flat. Cure the SU-8 glue to complete the preparation of the organic matter 202, as Figure 3 shown. Among them, the rotation speed of coating the SU-8 glue is 4500 revolutions, the curing temperature of the SU-8 glue is 230 o °C, and the curing time is 30 minutes.

[0045] Step S04: Use an ICP etcher to etch the inorganic passivation film 201 across the whole surface, removing part of the organic matter 201 until the inorganic passivation film 201 on the GaN mesa 103 is exposed, as Figure 4 shown. The etching gas used is O2.

[0046] Step S05: Coat a layer of 5312 positive photoresist on the surface of the sample after completing Step S04, and use photolithography technology to expose the area of the inorganic passivation film above the GaN mesa array 103, as Figure 5 shown.

[0047] Then use the remaining photoresist 203 as an etching mask layer, and use an ICP etcher to remove the inorganic passivation film 201 above the GaN mesa 103, as Figure 6 shown. Among them, part of the remaining photoresist 203 will also be etched. The etching gas used is a mixed gas of CF4 and CH4.

[0048] Finally, use an ICP etcher to remove the residual photoresist 203. The etching gas used is O2, as Figure 7 shown.

[0049] Step S06: Prepare a patterned N electrode 204 on the exposed GaN mesa 103, as Figure 8 shown. Part of the N electrode 204 extends into the upper surface of the GaN mesa 103. The material of the N electrode 204 is a stack of Cr / Pt / Au, and the thicknesses of Cr / Pt / Au are 30 nm, 100 nm, and 200 nm respectively.

[0050] In this embodiment, if part of the GaN mesa 103 falls off, the organic matter 202 can fill these fallen-off areas during the whole-surface etching, as Figure 9As shown in the figure. After the subsequent preparation of the N electrode 204, it will not cause a short circuit between the N electrode 204 and the P electrode 102. The organic matter 202 fills the trenches between the GaN-based Micro LED units, and the whole surface etching of the organic matter can also reduce the height difference between the bottom of the N electrode 204 and the upper surface of the GaN mesa 103, making the N electrode 204 not easily break, as Figure 10 shown. The organic matter 202 also plays a role in local planarization, and the surface of the prepared vertical structure Micro LED light-emitting module is flat, as Figure 11 shown, which is conducive to the subsequent process. Example 2

[0051] This embodiment provides a passivation process for a vertical structure Micro LED light-emitting module, and the specific steps are as follows: Step S01: Prepare GaN-based Micro LED units arranged in an array on the substrate 101. The GaN-based Micro LED units sequentially include a P electrode 102 and a GaN mesa 103 from bottom to top.

[0052] Step S02: Use PECVD to deposit an inorganic passivation film 201 on the periphery and top of the GaN-based Micro LED units, and on the trenches between the GaN-based Micro LED units. The inorganic passivation film 201 is a SiN x / SiO2 stack. The thickness of SiN x is 50 nm, and the thickness of SiO2 is 250 nm. The structure after depositing the inorganic passivation film 201 is as Figure 2 shown.

[0053] Step S03: Coat a layer of 1.5 μm thick PI glue on the surface of the inorganic passivation film 201. The PI glue fills the trenches between the GaN-based Micro LED units and keeps the surface flat. Imidize the PI glue to complete the preparation of the organic matter 202, as Figure 3 shown. Among them, the rotation speed of coating the SU-8 glue is 4500 revolutions, the imidization temperature is 260 o °C, and the time is 8 hours, and it is carried out under vacuum conditions.

[0054] Step S04: Use an ICP etching machine to etch the inorganic passivation film 201 on the whole surface, and remove part of the organic matter 201 until the inorganic passivation film 201 on the GaN mesa 103 is exposed, as Figure 4 shown, and the etching gas used is O2.

[0055] Step S05: Coat a layer of 5312 positive glue on the surface of the sample after completing Step S04, and use lithography technology to expose the area of the inorganic passivation film above the GaN mesa array 103, as Figure 5As shown. Then, the remaining photoresist 203 is used as an etching mask layer, and an ICP etching machine is used to remove the inorganic passivation film 201 above the GaN mesa 103, as Figure 6 shown. Among them, a part of the remaining photoresist 203 will also be etched, and the etching gas used is a mixed gas of CF4 and CH4. Finally, an ICP etching machine is used to remove the residual photoresist 203, and the etching gas used is O2, as Figure 7 shown.

[0056] Step S06: Prepare a patterned N electrode 204 on the exposed GaN mesa 103, as Figure 8 shown. Part of the N electrode 204 extends into the upper surface of the GaN mesa 103. The material of the N electrode 204 is a Cr / Au stack, and the thicknesses of Cr / Au are 30 nm and 200 nm respectively.

[0057] In this embodiment, if part of the GaN mesa 103 falls off, the organic matter 202 can fill these falling-off areas during the whole-surface etching, as Figure 9 shown. After the subsequent preparation of the N electrode 204, it will not cause a short circuit between the N electrode 204 and the P electrode 102. The organic matter 202 fills the trenches between the GaN-based Micro LED units, and the whole-surface etching of the organic matter can also reduce the height difference between the bottom of the N electrode 204 and the upper surface of the GaN mesa 103, making the N electrode 204 not easily break, as Figure 10 shown. The organic matter 202 also plays a role in local planarization, and the surface of the prepared vertical structure Micro LED light-emitting module is flat, as Figure 11 shown, which is conducive to the subsequent process. Comparative Example 1

[0058] This comparative example provides a conventional passivation process for a vertical structure Micro LED light-emitting module, and the specific steps are as follows: Step S01: Prepare an array of GaN-based Micro LED units on the substrate 101. The GaN-based Micro LED units include a P electrode 102 and a GaN mesa 103 from bottom to top in sequence. [[ID=:27]]

[0059] S02: Deposit an inorganic passivation film 201. The inorganic passivation film covers the GaN mesa 103, the side walls of the GaN-based Micro LED units, and the trenches between the GaN-based Micro LED units, as Figure 2 shown.

[0060] S05: Etch the inorganic passivation film 201 to expose the GaN mesa 103.

[0061] S06: Prepare a patterned N electrode 204 on the exposed GaN mesa 103, asFigure 12 as shown

[0062] In this comparative example, if some of the GaN mesa 103 falls off, a short circuit between the N electrode 204 and the P electrode 102 will occur after the N electrode 204 is fabricated subsequently. Moreover, the height difference between the bottom of the N electrode 204 and the upper surface of the GaN mesa 103 is relatively large, making the N electrode 204 prone to breakage, as Figure 12 shown

[0063] The above embodiments are only used to illustrate the design concept and features of the present invention, aiming to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design concepts disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A passivation process for a vertical structure Micro LED light-emitting module, characterized in that, It includes the following steps: S01. Prepare GaN-based Micro LED units arranged in an array on a substrate. The GaN-based Micro LED units sequentially include a P electrode and a GaN mesa from bottom to top; S02. Deposit an inorganic passivation film, which covers the GaN mesa, the sidewalls of the GaN-based Micro LED units, and the trenches between the GaN-based Micro LED units; S03. Prepare an organic material on the surface of the inorganic passivation film. The organic material fills the trenches between the GaN-based Micro LED units and has a flat surface; S04. Etch the organic material across the whole surface to expose the inorganic passivation film on the GaN mesa; S05. Etch the inorganic passivation film to expose the GaN mesa; S06. Prepare a patterned N electrode on the exposed GaN mesa.

2. The passivation process according to claim 1, characterized in that: The material of the inorganic passivation film is one or a combination of SiN x , SiO2 and Al2O3, and the thickness range of the inorganic passivation film is 100nm - 300nm.

3. The passivation process according to claim 1, characterized in that: The material of the inorganic passivation film is SiN x / SiO2 stack, the thickness of SiN x ranges from 20 nm to 50 nm, and the thickness of SiO2 ranges from 70 nm to 280 nm.

4. The passivation process according to claim 1, wherein: The material of the organic material is one of SU-8, polyimide, benzocyclobutene, SOG glass, and silane compounds. The thickness range of the organic material is 1.6 μm - 2.0 μm.

5. The passivation process according to claim 3, characterized in that: Step S In step S04, the method of etching the organic material across the whole surface is ICP etching, and the etching gas is one or several of O2, CF4, and CH4.

6. The passivation process according to claim 1, characterized in that, The specific steps of etching the inorganic passivation film in step S05 are as follows: S051. Coat a photoresist across the whole surface, perform photolithography on the photoresist to expose the inorganic passivation film on the GaN mesa; S052. Use the remaining photoresist as an etching mask, etch the inorganic passivation film by ICP to expose the GaN mesa, and remove the remaining photoresist.

7. The passivation process according to claim 6, characterized in that: The etching gas for ICP etching in step S052 is one or several of CF4, CH4, Cl2, and BCl3.

8. The passivation process according to claim 1, wherein, The specific steps of preparing the organic material in step S03 are as follows: S031. Coat a layer of organic material on the surface of the inorganic passivation film. The organic material fills the trenches between the GaN-based Micro LED units and has a flat surface; S032. Cure the organic material to complete the preparation of the organic material.

9. The passivation process according to claim 8, characterized in that: The method of curing the organic material in step S032 is thermal curing, and the curing temperature is 200°C - 280°C.

10. The passivation process according to claim 1, characterized in that: The material of the N electrode is one or several of Ti, Cr, Pt, Au, Al, Cu, and ITO. The thickness range of the N electrode is 100 nm - 400 nm.

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