Micro-led chip with Anti-reflective structure, and preparation method therefor

Abstract

The present invention relates to the technical field of semiconductors. Disclosed are a micro-LED chip with an anti-reflective structure, and a preparation method therefor. The surface of the micro-LED chip comprises a light-emitting region, a non-light-emitting region, and an IO region, wherein light-emitting pixels are disposed in the light-emitting region; and an anti-reflective structure is disposed in the non-light-emitting region, the anti-reflective structure and the light-emitting pixels are tiled on the surface of the micro-LED chip, and the anti-reflective structure has an uneven surface. Therefore, the problems of glaring and ghosting on an imaging end of a device are solved by means of the structural characteristics of the anti-reflective structure itself.

Description

Micro display chip with anti-reflection structure and preparation method thereof

[0001] The present application claims priority to the Chinese patent application No. 2024110351046, filed on July 31, 2024, and entitled "Micro display chip with anti-reflection structure and preparation method thereof", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of semiconductor technology, and in particular to a micro display chip with anti-reflection structure and a preparation method thereof. BACKGROUND

[0003] At present, micro display chips (Micro-LED chips) are widely used in the field of wearable devices, but there are problems of glare and ghosting at the imaging end of the device: there are a large number of metal and other high reflectivity structures on the surface of the Micro-LED chip, and the light reflected by the coupling light path is twice reflected by these structures and then enters the coupling light path again, finally causing the problem of peripheral glare and ghosting at the imaging end.

[0004] In related technologies, after the Micro-LED chip is packaged, organic black glue (BM) is set on the packaged device to solve this problem by using organic black glue to absorb light (as shown in FIG. 1), but the absorption of light by organic black glue has an upper limit, and the high-temperature resistance and mechanical properties are limited, which greatly reduces the reliability of the Micro-LED chip.

[0005] Therefore, there is an urgent need for a new technical solution to solve the problem of the light reflected twice on the surface of the Micro-LED chip affecting the imaging effect at the imaging end of the device. SUMMARY

[0006] The purpose of the present application is to provide a micro display chip with anti-reflection structure and a preparation method thereof, which can diffuse the light reflected twice on the surface of the Micro-LED chip by the structural characteristics of the anti-reflection structure itself to avoid affecting the imaging effect at the imaging end of the device.

[0007] To achieve the above-mentioned purpose of the application, the present application proposes the following technical solutions:

[0008] On the one hand, a micro display chip with anti-reflection structure is provided, the surface of the micro display chip comprising: a light emitting area, a non-light emitting area and an IO area;

[0009] The light emitting area is provided with a light emitting pixel;

[0010] The non-light emitting area is provided with an anti-reflection structure, and the anti-reflection structure and the light emitting pixel are arranged in a tiled manner on the surface of the micro display chip.

[0011] The anti-reflection structure has a rough surface.

[0012] In a possible implementation, the anti-reflection structure includes a plurality of anti-reflection units, and the plurality of anti-reflection units are convex in a direction away from the surface of the micro display chip.

[0013] In a possible implementation, the anti-reflection structure is configured to diffuse the reflected light rays, which are formed by reflection of light rays emitted by the light emitting pixels of the light emitting region on the imaging end opposite to the micro display chip.

[0014] In a possible implementation, the anti-reflection structure includes anti-reflection units, and the anti-reflection units are microlens units.

[0015] In a possible implementation, the outer surface of the light emitting pixels on the light emitting region is provided with a microlens structure of the same material or different material as the microlens units.

[0016] Or,

[0017] The top of the light emitting pixels on the light emitting region is provided with a microlens structure of the same material or different material as the microlens units.

[0018] In a possible implementation, the anti-reflection structure adopts an organic material, and the organic material includes any one of the following: SU8, polyimide.

[0019] In a possible implementation, the anti-reflection structure adopts an inorganic material, and the inorganic material includes any one of the following: oxide, nitride, oxynitride.

[0020] In a possible implementation, the anti-reflection units in the anti-reflection structure are roughened compound pixel units, and the compound pixel units and the light emitting pixels adopt the same material.

[0021] In a possible implementation, the compound pixel material adopted by the anti-reflection structure includes any one of the following: gallium nitride, gallium arsenide, aluminum gallium indium phosphorus.

[0022] In a possible implementation, a passivation layer is arranged on the anti-reflection structure.

[0023] In a possible implementation, each anti-reflection unit has a shape of any one of the following: cone, cylinder, hemisphere, half-olive ball, square column, triangular pyramid.

[0024] In a possible implementation, the anti-reflection structure corresponds to a fill ratio greater than 50%, the fill ratio being a ratio of a total area of the anti-reflection structure to a total area of the non-light-emitting region.

[0025] In a possible implementation, a ratio of a height to a diameter of each of the anti-reflection units is greater than or equal to 0.5.

[0026] In a possible implementation, an interval between each of the anti-reflection units ranges from 0.5 to 5 μm.

[0027] In another aspect, a method for manufacturing a micro display chip is also provided, the micro display chip including a surface including a light-emitting region, a non-light-emitting region, and an IO region, the method including:

[0028] manufacturing a light-emitting pixel on the light-emitting region and manufacturing an anti-reflection structure on the non-light-emitting region, the anti-reflection structure being arranged in a tiled manner with the light-emitting pixel on the surface of the micro display chip;

[0029] In a possible implementation, the anti-reflection structure includes a plurality of anti-reflection units, the anti-reflection units being micro-lens units.

[0030] In a possible implementation, the anti-reflection structure includes a plurality of anti-reflection units, the anti-reflection units being micro-lens units.

[0031] The manufacturing of the light-emitting pixel on the light-emitting region and the manufacturing of the anti-reflection structure on the non-light-emitting region include:

[0032] manufacturing the light-emitting pixel on the light-emitting region;

[0033] spin-coating an organic material on the light-emitting region and the non-light-emitting region to form a lens material layer, the lens material layer being arranged on the light-emitting pixel;

[0034] performing photolithography on the lens material layer to form a plurality of lens intermediate structures with a planar surface type on the light-emitting region and the non-light-emitting region;

[0035] performing thermal reflow on the lens intermediate structures to convert the lens intermediate structures to a curved surface type, to obtain a micro-lens structure on the light-emitting pixel and the micro-lens units on the non-light-emitting region.

[0036] In a possible implementation, the anti-reflection structure includes a plurality of anti-reflection units, the anti-reflection units being micro-lens units.

[0037] The manufacturing of the light-emitting pixel on the light-emitting region and the manufacturing of the anti-reflection structure on the non-light-emitting region include:

[0038] preparing the light-emitting pixel on the light-emitting region;

[0039] filling inorganic material on the light-emitting region, the non-light-emitting region to form a lens material layer, the lens material layer is arranged on the light-emitting pixel;

[0040] lithography and plasma etching are performed on the lens material layer to form a plurality of lens intermediate structures with planar surface type on the light-emitting region, the non-light-emitting region;

[0041] The lens intermediate structure is subjected to ion beam etching to convert the lens intermediate structure into a curved surface type, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting region.

[0042] In a possible implementation, the anti-reflection structure includes a plurality of anti-reflection units, and the anti-reflection unit is a microlens unit.

[0043] The preparing the light-emitting pixel on the light-emitting region and the preparing the anti-reflection structure on the non-light-emitting region include:

[0044] preparing the light-emitting pixel on the light-emitting region;

[0045] filling inorganic material on the light-emitting region, the non-light-emitting region to form a lens material layer, the lens material layer is arranged on the light-emitting pixel;

[0046] preparing a photoresist structure on the lens material layer, and performing thermal reflow on the photoresist structure to convert the photoresist structure into a curved surface type;

[0047] Plasma etching is performed on the lens material layer to transfer the curved surface type of the photoresist structure to the lens material layer, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting region.

[0048] In a possible implementation, the anti-reflection structure includes an anti-reflection unit, and the anti-reflection unit is a roughened compound pixel unit.

[0049] The preparing the light-emitting pixel on the light-emitting region and the preparing the anti-reflection structure on the non-light-emitting region include:

[0050] bonding compound pixel material on the light-emitting region, the non-light-emitting region to form a compound pixel material layer;

[0051] pixelating the compound pixel material layer on the light-emitting region to form the light-emitting pixel;

[0052] Coarsen the compound pixel material layer on the light-emitting pixel and the non-light-emitting area to obtain a coarsened light-emitting pixel on the light-emitting area and a coarsened compound pixel unit on the non-light-emitting area.

[0053] In a possible implementation, the method further includes:

[0054] Depositing an insulating medium on the surface of the light-emitting pixel and the surface of the anti-reflection structure to form a passivation layer.

[0055] Compared with the prior art, the present application has the following beneficial effects:

[0056] A micro display chip with an anti-reflection structure is provided, the light-emitting area is provided with a light-emitting pixel, the non-light-emitting area is provided with an anti-reflection structure, the anti-reflection structure and the light-emitting pixel are arranged in a tiled manner on the surface of the micro display chip, the anti-reflection structure has a rough surface, and the anti-reflection structure is used for diffusing the incident reflected light, the light is diffused by the structure itself, compared with the way of absorbing light by using an organic black glue or other light-absorbing material, the anti-reflection performance is ensured, and the high-temperature resistance and mechanical performance are stronger than those of the light-absorbing material.

[0057] Further, the anti-reflection structure can be formed by using an organic material or an inorganic material, and the micro lens process and the anti-reflection structure can be simultaneously performed, and the compound pixel material and the coarsening process can be simultaneously performed, so that a separate anti-reflection layer processing procedure is not needed, and the process is more simplified. BRIEF DESCRIPTION OF DRAWINGS

[0058] FIG. 1 is a structure diagram of a micro display chip provided with an organic black glue on the surface of the micro display chip according to the related art;

[0059] FIG. 2 is a structure diagram of a micro display chip provided with an anti-reflection structure on the surface of the micro display chip according to an embodiment of the present application;

[0060] FIG. 3 is a structure diagram of an anti-reflection unit in the anti-reflection structure according to an embodiment of the present application;

[0061] FIG. 4 is a diagram of arrangement of the anti-reflection structure according to an embodiment of the present application;

[0062] FIG. 5 is a diagram of reflectivity comparison of different anti-reflection structures according to an embodiment of the present application;

[0063] FIG. 6 is a diagram of reflectivity comparison of different anti-reflection structures according to an embodiment of the present application;

[0064] FIG. 7 is a diagram of reflectivity comparison of different anti-reflection structures according to an embodiment of the present application;

[0065] Fig. 8 is a schematic diagram of reflectivity contrast of different anti-reflective structures according to an embodiment of the present application;

[0066] Fig. 9 is a schematic diagram of an anti-reflective unit as a microlens unit according to an embodiment of the present application;

[0067] Fig. 10 is a schematic diagram of an anti-reflective unit as a roughened compound pixel unit according to an embodiment of the present application;

[0068] Fig. 11 is a flow chart of a method for preparing a micro-display chip according to an embodiment of the present application;

[0069] Fig. 12 is a schematic diagram of a preparation process for preparing an anti-reflective structure on a surface of a micro-display chip according to an embodiment of the present application;

[0070] Fig. 13 is a schematic diagram of a preparation process for preparing an anti-reflective structure on a surface of a micro-display chip according to an embodiment of the present application;

[0071] Fig. 14 is a schematic diagram of a preparation process for preparing an anti-reflective structure on a surface of a micro-display chip according to an embodiment of the present application;

[0072] Fig. 15 is a schematic diagram of a preparation process for preparing an anti-reflective structure on a surface of a micro-display chip according to an embodiment of the present application;

[0073] Fig. 16 is a schematic diagram of an anti-reflective unit as a microlens unit according to an embodiment of the present application.

[0074] Reference signs: 100 - micro-display chip, 10 - anti-reflective structure, 20 - light-emitting pixel, 30 - passivation layer, 40 - high-reflective material. DETAILED DESCRIPTION

[0075] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0076] In the description of the present application, it needs to be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0077] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0078] In order to solve the problem of imaging glare and ghosting caused by the surface reflection of the Micro-LED chip, the related technology provides a solution of setting light-absorbing materials such as organic black glue (BM), which has poor anti-reflection ability, poor mechanical performance and poor reliability.

[0079] In order to avoid the above problems, in the embodiments of the present application, a new anti-reflection structure is proposed, which is prepared on the area of the Micro-LED chip surface that needs anti-reflection, and the light reaching the surface is diffusely reflected, so that it cannot enter the coupling light path, thereby solving the problem of glare and ghosting existing in the imaging end of the device.

[0080] Next, the device structure proposed in the present application is described.

[0081] Firstly, the present application provides a micro display chip 100 with an anti-reflection structure 10, the surface of the micro display chip 100 includes: a light emitting area, a non-light emitting area and an IO area.

[0082] As shown in FIGS. 9 and 10, the light emitting area is provided with a light emitting pixel 20; the non-light emitting area is provided with an anti-reflection structure 10, and the anti-reflection structure 10 and the light emitting pixel 20 are arranged in a tiled manner on the surface of the micro display chip 100.

[0083] The anti-reflection structure 10 has an uneven surface and is used to diffusely reflect incident reflected light. The reflected light is, for example, light emitted by the light-emitting pixel 20 in the light-emitting area and reflected by the imaging end that is positioned opposite to the microdisplay chip 100.

[0084] In this embodiment of the application, as shown in FIG2, the micro display chip 100 includes a high reflective material 40. The high reflective material 40 may specifically include the metal electrodes used in the integrated circuit substrate and the light-emitting pixel 20 in the micro display chip 100. In response to the secondary reflection of emitted light by the high reflective material 40, an anti-reflection structure 10 is provided on the surface of the non-light-emitting area of ​​the micro display chip 100. The anti-reflection structure 10 has an uneven surface and can be a light-transmitting material. Instead of absorbing light, it has a diffuse reflection function based on its structural characteristics. It can diffusely reflect the light that reaches the surface of the non-light-emitting area (i.e., the reflected light formed by the reflection at the imaging end), avoiding the reflected light from entering the coupling optical path after secondary reflection, thereby avoiding the glare and ghosting problems at the imaging end of the device caused by this part of the light.

[0085] Optionally, the anti-reflective structure 10 includes one or more anti-reflective units, which protrude in a direction away from the surface of the microdisplay chip 100, so that the anti-reflective structure 10 has an uneven surface. For example, in the embodiment of FIG10, the anti-reflective structure 10 includes a single anti-reflective unit, and in the embodiment of FIG9, the anti-reflective structure 10 includes multiple anti-reflective units.

[0086] Each anti-reflective unit can be in any of the following shapes: cone, cylinder, hemisphere, semi-oval, square prism, or triangular pyramid. In this embodiment, the anti-reflective units in the anti-reflective structure 10 can protrude from the surface of the non-light-emitting area of ​​the microdisplay chip 100 in various shapes. Furthermore, the anti-reflective units can have the same or different shapes, and this application does not impose any restrictions on this.

[0087] In this design, the height-to-diameter ratio of each anti-reflective unit is greater than or equal to 0.5. For an anti-reflective unit whose projection on the surface of the microdisplay chip 100 is circular, the diameter of the anti-reflective unit refers to the diameter of the projection. For an anti-reflective unit whose projection on the surface of the microdisplay chip 100 is non-circular, the diameter of the anti-reflective unit refers to the distance between the two farthest points in its projection. The height-to-diameter ratio of each anti-reflective unit affects the unevenness of the chip surface, as shown in Figure 3. The height of the anti-reflective unit is denoted as H, and the diameter as D. To ensure the diffuse reflection effect of the anti-reflective structure 10, the ratio of height H to diameter D is greater than or equal to 0.5. Furthermore, the characteristic dimension of H is 0.25-25 μm.

[0088] The spacing between each antireflective unit ranges from 0.5 to 5 μm, specifically referring to the center-to-center distance between two adjacent units. The spacing between each antireflective unit affects the surface roughness of the chip; if it is too small, it becomes difficult to fabricate. As shown in Figure 3, the size of the periodic antireflective unit is denoted as P, where P represents the spacing between the antireflective units. To ensure the diffuse reflection effect of the antireflective structure 10 and facilitate fabrication, the size P of the periodic antireflective unit is set between 0.5 and 5 μm. Furthermore, the diameter D of the antireflective unit must be less than or equal to P, and the characteristic dimension of D is 0.25–5 μm.

[0089] In one possible implementation, the fill ratio of the anti-reflective structure 10 is greater than 50%, and the fill ratio is the ratio of the total projected area of ​​the anti-reflective structure 10 to the total area of ​​the non-light-emitting area.

[0090] In this implementation, by designing the fill ratio to be greater than 50%, it can be ensured that the anti-reflection structure 10 occupies a sufficiently high proportion of the total area of ​​the anti-reflection surface, thereby ensuring the diffuse reflection effect of the anti-reflection structure 10.

[0091] To achieve a fill ratio greater than 50%, the arrangement of the anti-reflective structures 10 can be controlled. For example, referring to Figure 4, in one instance, the anti-reflective structures 10 use a one-dimensional close arrangement. In this arrangement, each anti-reflective unit in the anti-reflective structure 10 is linearly arranged, with each unit lying on two straight lines in a first direction and a second direction, which are perpendicular. The maximum fill ratio is 78.5%. To further improve the fill ratio, the anti-reflective structure 10 can use other arrangements to further reduce reflectivity and improve anti-reflective performance. In a two-dimensional close arrangement, the fill ratio can be increased to a maximum of 90.7%. In this two-dimensional close arrangement, each anti-reflective unit in the anti-reflective structure 10 is hexagonal and arranged in a honeycomb pattern on a plane.

[0092] It can be pointed out that, when P is the same, the larger the fill ratio, the smaller the reflectivity, and the stronger the diffuse reflection effect of the anti-reflection structure 10; when the fill ratio is the same, the smaller P is, the smaller the reflectivity, and the stronger the diffuse reflection effect of the anti-reflection structure 10.

[0093] Figure 5 shows Group A, where P is 2.5 μm. When the diameter D of the anti-reflective structure 10 corresponding to this application is 1.85 μm (marked as A1.85 in the figure) and 2.1 μm (marked as A2.1 in the figure), the reflectivity of the surface of the anti-reflective structure 10 is compared with that of the Au metal surface and the organic black glue (BM) surface. In the field of Micro-LED display, within the wavelength range of blue, green and red light chips of 440nm-640nm, the reflectivity of the anti-reflective structure 10 marked as A2.1 corresponding to this application is lower than that of the organic black glue (BM), and its anti-reflective ability is better than that of the organic black glue (BM).

[0094] Figure 6 shows Group B, where P is 3.75 μm. The reflection of the anti-reflective structure 10 corresponding to this application is compared with the reflection of Au metal surface and organic black glue (BM) surface when the diameter D is 2.0 μm (labeled B2.0), 2.25 μm (labeled B2.25), 2.75 μm (labeled B2.75), and 3.25 μm (labeled B3.25) respectively. For the same P, the larger the diameter D of the anti-reflective structure 10 corresponding to this application, the larger the fill ratio. It can be seen that the larger the fill ratio of the anti-reflective structure 10 corresponding to this application, the smaller the reflectivity and the stronger the anti-reflective ability.

[0095] Figure 7 shows Group C, where P is 5 μm. The diameter D of the anti-reflective structure 10 corresponding to this application is 1.95 μm (marked as C1.95 in the figure), 2.45 μm (marked as C2.45 in the figure), 2.85 μm (marked as C2.85 in the figure), 3.35 μm (marked as C3.35 in the figure), 3.80 μm (marked as 3.80 in the figure), and 4.30 μm (marked as C4.30 in the figure). The reflectivity of the surface of the anti-reflective structure 10 is compared with that of the Au metal surface and the organic black glue (BM) surface. For the same P, the larger the diameter D of the anti-reflective structure 10 corresponding to this application, the larger the fill ratio. It can be seen that the larger the fill ratio of the anti-reflective structure 10 corresponding to this application, the smaller the reflectivity and the stronger the anti-reflective ability.

[0096] Figure 8 shows a comparison of the reflectivity of the three structural surfaces (A2.1, B3.25, and C4.30) mentioned above with the reflectivity of the Au metal surface and the organic black glue (BM) surface. The filling ratios of these three structures are similar, at 55%, 59%, and 58%, respectively. It can be seen that, at the same filling ratio, the smaller the P value of the anti-reflection structure 10 corresponding to this application, the lower the reflectivity and the stronger the anti-reflection capability.

[0097] In one possible implementation, as shown in Figure 9, the anti-reflection unit in the anti-reflection structure 10 is a microlens unit.

[0098] In this implementation, the anti-reflection structure 10 can be fabricated using the same process as the microlens structure corresponding to the light-emitting pixel 20 in the light-emitting area, and can be fabricated simultaneously. Therefore, the anti-reflection unit in the anti-reflection structure 10 is presented as a microlens unit.

[0099] Optionally, as shown in Figure 9, the outer surface of the light-emitting pixel 20 in the light-emitting area is provided with a microlens structure made of the same material as the microlens unit. It is understood that in other implementations, the anti-reflection structure 10 can be fabricated using different processes and in different steps than the microlens structure corresponding to the light-emitting pixel 20 in the light-emitting area, and the materials of the microlens structure of the anti-reflection structure 10 and the microlens structure on the outer surface of the light-emitting pixel 20 can be the same or different.

[0100] As shown in Figure 16, the light-emitting pixel 20 on the light-emitting area is located in the insulating layer, and a microlens structure made of the same material or a different material as the microlens unit is disposed above the light-emitting pixel 20.

[0101] It is understandable that the relative position between the microlens structure and the light-emitting pixel 20 can be adjusted based on the needs of optical control effect of the light-emitting pixel 20.

[0102] Furthermore, the anti-reflective structure 10 is made of organic materials, including any one of the following: SU8 and polyimide. That is, the anti-reflective structure 10 in the form of a microlens unit can be made of organic materials such as SU8 and polyimide.

[0103] Furthermore, the anti-reflective structure 10 is made of inorganic materials, including any one of the following: oxides, nitrides, and oxynitrides. That is, the anti-reflective structure 10 in the form of a microlens unit can be made of inorganic materials such as oxides, nitrides, and oxynitrides.

[0104] In another possible implementation, as shown in Figure 10, the anti-reflection unit in the anti-reflection structure 10 is a coarsened compound pixel unit, and the compound pixel unit and the light-emitting pixel 20 use the same material.

[0105] In this implementation, the anti-reflection structure 10 can be fabricated simultaneously with the light-emitting pixel 20 in the coarsened light-emitting area using the same process. Therefore, the anti-reflection unit in the anti-reflection structure 10 appears as a coarsened compound pixel unit. It can be understood that the anti-reflection structure 10 can be a single layer, or multiple independent anti-reflection structures 10 can be set on multiple regions in the non-light-emitting area.

[0106] Furthermore, the compound pixel material used in the anti-reflection structure 10 includes any one of the following: gallium nitride, gallium arsenide, and aluminum gallium indium phosphide. That is, the anti-reflection structure 10 in the form of a coarsened compound pixel unit can be fabricated using compound pixel materials such as gallium nitride, gallium arsenide, and aluminum gallium indium phosphide.

[0107] Furthermore, a passivation layer 30 (not shown in Figure 10) is disposed on the anti-reflection structure 10. The passivation layer 30 provides insulation protection for the anti-reflection structure 10 formed in the form of coarsened compound pixel units. The passivation layer 30 can be a single layer or a stack of insulating dielectric layers such as aluminum oxide, silicon nitride, or silicon oxide.

[0108] Understandably, compared to light-absorbing materials such as organic black glue, the high-temperature resistant transparent materials such as SU8 and polyimide, as well as various inorganic transparent materials mentioned above, have higher reliability and stronger anti-reflection capabilities.

[0109] In summary, this application provides a microdisplay chip with an anti-reflective structure. The light-emitting area has light-emitting pixels, and the non-light-emitting area has an anti-reflective structure. The anti-reflective structure and the light-emitting pixels are laid flat on the surface of the microdisplay chip. The anti-reflective structure has an uneven surface and is used to diffusely reflect incident reflected light. By diffusely reflecting light through the structure itself, compared to absorbing light with light-absorbing materials such as organic black glue, it ensures a certain level of anti-reflective performance while also exhibiting superior high-temperature resistance and mechanical properties compared to light-absorbing materials.

[0110] Furthermore, the formation of the anti-reflective structure can be achieved using organic or inorganic materials, simultaneously with the microlens process. Alternatively, compound pixel materials can be used in conjunction with the roughening process, eliminating the need for a separate anti-reflective layer processing step and simplifying the process.

[0111] The fabrication method of the microdisplay chip corresponding to the structure in the above embodiments will be described below. As shown in Figure 11, the fabrication method of the microdisplay chip may include the following steps:

[0112] Step S1: Prepare light-emitting pixels on the light-emitting area and prepare an anti-reflective structure on the non-light-emitting area. The anti-reflective structure and the light-emitting pixels are laid flat on the surface of the microdisplay chip; wherein, the anti-reflective structure has an uneven surface.

[0113] The anti-reflection structure is used to diffusely reflect incident reflected light. The reflected light is, for example, light emitted by the light-emitting pixels in the light-emitting area and reflected by the imaging end that is positioned opposite to the microdisplay chip.

[0114] Among them, anti-reflective structures can be made of organic materials, such as SU8, polyimide and other high-temperature resistant materials (≥200℃), through processes such as photolithography, photoresist melting, laser direct writing and nanoimprinting. They can also be made of inorganic materials through processes such as plasma etching and ion beam etching. Alternatively, the surface of compound pixel materials such as gallium nitride (GaN) and aluminum gallium indium phosphide (AlGaInP) can be roughened to form an anti-reflective structure.

[0115] In one embodiment, referring to FIG12, the anti-reflection structure includes multiple anti-reflection units, which are microlens units. While fabricating the organic microlens structure in the light-emitting area, the anti-reflection structure 10 is fabricated in the non-light-emitting area. Accordingly, step S1 may specifically include:

[0116] (1) Prepare light-emitting pixels on the light-emitting area.

[0117] (2) Organic material is spin-coated on the light-emitting area and the non-light-emitting area to form a lens material layer, which is then applied over the light-emitting pixel.

[0118] Among them, organic materials can be high-temperature resistant materials (≥200℃) such as SU8 and polyimide.

[0119] (3) Photolithography is performed on the lens material layer to form multiple intermediate lens structures with planar surface shapes on the light-emitting area and the non-light-emitting area.

[0120] (4) Perform thermal reflow on the lens intermediate structure to transform the lens intermediate structure into a curved surface, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

[0121] In one embodiment, referring to FIG13, the anti-reflection structure includes multiple anti-reflection units, which are microlens units. While an inorganic microlens structure is fabricated in the light-emitting area, an anti-reflection structure 10 is fabricated in the non-light-emitting area. Accordingly, step S1 may specifically include:

[0122] (1) Prepare light-emitting pixels on the light-emitting area.

[0123] (2) Inorganic materials are filled into the light-emitting area and the non-light-emitting area to form a lens material layer, which is then placed on the light-emitting pixel.

[0124] Among them, inorganic materials can be inorganic silicon oxide, silicon nitride, aluminum oxide, etc., including inorganic silicon oxide or nitrogen oxides prepared by PSG (phosphate glass), BPSG (borophosphosilicate glass) process or by deposition sources such as TEOS (tetraethoxysilane) and TEPO (triethyl phosphate).

[0125] (3) Photolithography and plasma etching are performed on the lens material layer to form multiple intermediate lens structures with planar surface shapes in the light-emitting area and the non-light-emitting area.

[0126] (4) Ion beam etching is performed on the intermediate structure of the lens to transform the intermediate structure of the lens into a curved surface, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

[0127] In one embodiment, referring to FIG14, the anti-reflection structure includes multiple anti-reflection units, which are microlens units. While an inorganic microlens structure is fabricated in the light-emitting area, an anti-reflection structure 10 is fabricated in the non-light-emitting area. Accordingly, step S1 may specifically include:

[0128] (1) Prepare light-emitting pixels on the light-emitting area.

[0129] (2) Inorganic materials are filled into the light-emitting area and the non-light-emitting area to form a lens material layer, which is then placed on the light-emitting pixel.

[0130] Among them, inorganic materials can be inorganic silicon oxide, silicon nitride, aluminum oxide, etc., including inorganic silicon oxide or nitrogen oxides prepared by PSG (phosphate glass), BPSG (borophosphosilicate glass) process or by deposition sources such as TEOS (tetraethoxysilane) and TEPO (triethyl phosphate).

[0131] (3) A photoresist structure is prepared on the lens material layer, and the photoresist structure is subjected to thermal reflow to transform the photoresist structure into a curved surface.

[0132] (4) Plasma etching is performed on the lens material layer to transfer the curved surface of the photoresist structure to the lens material layer, resulting in the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

[0133] In one embodiment, referring to FIG15, the anti-reflection structure includes an anti-reflection unit, which is a roughened compound pixel unit. While the surface of the light-emitting pixel is roughened, an anti-reflection structure 10 is fabricated in the non-light-emitting area; correspondingly, step S1 may specifically include:

[0134] (1) Bond compound pixel materials to the light-emitting region and the non-light-emitting region to form a compound pixel material layer.

[0135] (2) Pixelate the compound pixel material layer on the light-emitting area to form a light-emitting pixel.

[0136] (3) Roughen the compound pixel material layer on the light-emitting pixel and the non-light-emitting area to obtain the roughened light-emitting pixel on the light-emitting area and the roughened compound pixel unit on the non-light-emitting area.

[0137] Furthermore, as shown in Figure 15, after the roughening process is completed, an insulating dielectric can be deposited on the surface of the light-emitting pixel and the surface of the anti-reflection structure to form a passivation layer 30. In addition, a common cathode layer and microlenses can be further fabricated on the light-emitting pixel 20 in the light-emitting region.

[0138] In summary, the microdisplay chip fabrication method provided in this application embodiment involves setting light-emitting pixels on the light-emitting area and setting an anti-reflection structure on the non-light-emitting area. The anti-reflection structure and the light-emitting pixels are laid flat on the surface of the microdisplay chip. The anti-reflection structure has an uneven surface and is used to diffusely reflect incident reflected light. By diffusely reflecting light through the structure itself, compared with the method of absorbing light through light-absorbing materials such as organic black glue, it not only ensures a certain anti-reflection performance, but also has stronger high temperature resistance and mechanical properties than light-absorbing materials.

[0139] Furthermore, the formation of the anti-reflective structure can be achieved using organic or inorganic materials, simultaneously with the microlens process. Alternatively, compound pixel materials can be used in conjunction with the roughening process, eliminating the need for a separate anti-reflective layer processing step and simplifying the process.

[0140] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention. That is, any number of embodiments can be combined to meet the needs of different application scenarios. All of these are within the protection scope of this application and will not be described in detail here.

[0141] It should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A microdisplay chip with an anti-reflective structure, characterized in that, The surface of the microdisplay chip includes: a light-emitting area, a non-light-emitting area, and an I / O area; The light-emitting area is provided with light-emitting pixels; An anti-reflective structure is provided on the non-light-emitting area, and the anti-reflective structure and the light-emitting pixels are laid flat on the surface of the microdisplay chip. The anti-reflective structure has an uneven surface.

2. The microdisplay chip according to claim 1, characterized in that, The anti-reflection structure includes multiple anti-reflection units, which protrude in a direction away from the surface of the microdisplay chip.

3. The microdisplay chip according to claim 1, characterized in that, The anti-reflection structure is used to diffusely reflect the incident reflected light, which is the light emitted by the light-emitting pixels of the light-emitting area and reflected by the imaging end that is positioned opposite to the microdisplay chip.

4. The microdisplay chip according to claim 2, characterized in that, The anti-reflection unit in the anti-reflection structure is a microlens unit.

5. The microdisplay chip according to claim 4, characterized in that, The outer surface of the light-emitting pixel in the light-emitting area is provided with a microlens structure made of the same material or a different material than the microlens unit; or, Above the light-emitting pixels in the light-emitting area, a microlens structure made of the same material or a different material from the microlens unit is disposed.

6. The microdisplay chip according to claim 4, characterized in that, The anti-reflective structure is made of organic materials, including any one of the following: SU8, polyimide.

7. The microdisplay chip according to claim 4, characterized in that, The anti-reflective structure is made of inorganic materials, which include any one of the following: oxides, nitrides, and nitrogen oxides.

8. The microdisplay chip according to claim 1, characterized in that, The anti-reflection structure includes an anti-reflection unit, which is a coarsened compound pixel unit, and the compound pixel unit and the light-emitting pixel are made of the same material.

9. The microdisplay chip according to claim 8, characterized in that, The anti-reflection structure uses compound pixel materials including any one of the following: gallium nitride, gallium arsenide, and aluminum gallium indium phosphide.

10. The microdisplay chip according to claim 8, characterized in that, A passivation layer is provided on the anti-reflection structure.

11. The microdisplay chip according to claim 1, characterized in that, Each of the anti-reflective units can be in the shape of any of the following: cone, cylinder, hemisphere, semi-oval, square prism, or triangular pyramid.

12. The microdisplay chip according to claim 1, characterized in that, The fill ratio corresponding to the anti-reflective structure is greater than 50%, and the fill ratio is the ratio of the total projected area of ​​the anti-reflective structure to the total area of ​​the non-light-emitting area.

13. The microdisplay chip according to claim 1, characterized in that, The height-to-diameter ratio of each anti-reflective unit is greater than or equal to 0.

5.

14. The microdisplay chip according to claim 1, characterized in that, The phase spacing between each of the antireflective units ranges from 0.5 to 5 μm.

15. A method for fabricating a microdisplay chip, characterized in that, The method is used to prepare a microdisplay chip as described in any one of claims 1 to 14, wherein the surface of the microdisplay chip includes: a light-emitting region, a non-light-emitting region, and an I / O region, and the method includes: Light-emitting pixels are fabricated on the light-emitting area, and an anti-reflective structure is fabricated on the non-light-emitting area. The anti-reflective structure and the light-emitting pixels are arranged in a flat manner on the surface of the microdisplay chip. The anti-reflective structure has an uneven surface.

16. The method according to claim 15, characterized in that, The anti-reflection structure includes multiple anti-reflection units, and each anti-reflection unit is a microlens unit. The step of fabricating light-emitting pixels on the light-emitting area and fabricating an anti-reflection structure on the non-light-emitting area includes: The light-emitting pixel is prepared on the light-emitting area; Organic material is spin-coated onto the light-emitting area and the non-light-emitting area to form a lens material layer, which is then deposited over the light-emitting pixel. Photolithography is performed on the lens material layer to form multiple intermediate lens structures with planar surface shapes on the light-emitting area and the non-light-emitting area; The intermediate structure of the lens is subjected to thermal reflow to transform it into a curved surface, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

17. The method according to claim 15, characterized in that, The anti-reflection structure includes multiple anti-reflection units, and each anti-reflection unit is a microlens unit. The step of fabricating light-emitting pixels on the light-emitting area and fabricating an anti-reflection structure on the non-light-emitting area includes: The light-emitting pixel is prepared on the light-emitting area; Inorganic material is filled into the light-emitting area and the non-light-emitting area to form a lens material layer, and the lens material layer is applied over the light-emitting pixel; Photolithography and plasma etching are performed on the lens material layer to form multiple intermediate lens structures with planar surface shapes on the light-emitting area and the non-light-emitting area; The intermediate structure of the lens is etched by an ion beam to transform it into a curved surface, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

18. The method according to claim 15, characterized in that, The anti-reflection structure includes multiple anti-reflection units, and each anti-reflection unit is a microlens unit. The step of fabricating light-emitting pixels on the light-emitting area and fabricating an anti-reflection structure on the non-light-emitting area includes: The light-emitting pixel is prepared on the light-emitting area; Inorganic material is filled into the light-emitting area and the non-light-emitting area to form a lens material layer, and the lens material layer is applied over the light-emitting pixel; A photoresist structure is fabricated on the lens material layer, and the photoresist structure is subjected to thermal reflow to transform the photoresist structure into a curved surface. Plasma etching is performed on the lens material layer to transfer the curved surface of the photoresist structure to the lens material layer, thereby obtaining the microlens structure on the light-emitting pixel and the microlens unit on the non-light-emitting area.

19. The method according to claim 14, characterized in that, The anti-reflection structure includes an anti-reflection unit, which is a coarsened compound pixel unit; The step of fabricating light-emitting pixels on the light-emitting area and fabricating an anti-reflection structure on the non-light-emitting area includes: A compound pixel material is bonded to the light-emitting region and the non-light-emitting region to form a compound pixel material layer; The compound pixel material layer on the light-emitting region is pixelated to form the light-emitting pixel; The light-emitting pixel and the compound pixel material layer on the non-light-emitting area are roughened to obtain the roughened light-emitting pixel on the light-emitting area and the roughened compound pixel unit on the non-light-emitting area.

20. The method according to claim 19, characterized in that, The method further includes: An insulating medium is deposited on the surface of the light-emitting pixel and the surface of the anti-reflective structure to form a passivation layer.

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