Micro LED micro display chip and its manufacturing method

Abstract

The present invention discloses a micro LED microdisplay chip and a manufacturing method thereof, the micro LED microdisplay chip comprising: a driving panel; a plurality of LED units arranged on the driving panel; a fence structure having a plurality of grid holes; and a wavelength conversion layer disposed on the fence structure, the plurality of LED units having a plurality of LED mesas corresponding to each other, each of which can be individually driven by the driving panel; the plurality of grid holes surrounding the plurality of LED mesas, each of which has a recessed area formed between the LED mesa and the corresponding grid hole; the wavelength conversion layer including a first wavelength conversion layer having a plurality of first wavelength conversion units filling the corresponding recessed area; the LED units emitting a first color light, and the first wavelength conversion units converting the first color light into a second color light.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS The present invention claims priority to a Chinese patent application filed with the China Patent Office on November 9, 2022, bearing application number 202211400408.9 and entitled "Micro LED microdisplay chip and manufacturing method thereof," the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present invention relates to the field of LED display technology, and more particularly to a micro LED micro display chip and a manufacturing method thereof. [Background technology]

[0003] Modern society is becoming increasingly information-based and is evolving towards smarter technologies. Display is an important element for realizing information exchange and smarter technologies. Among the many display technologies currently available, micro LED display technology is considered a groundbreaking next-generation display technology and is attracting widespread attention. Micro LED display technology is a self-luminous display technology that integrates arrayed micrometer-sized LED units (also called LED light-emitting units) on an active addressing drive panel and outputs display images by individually controlling and lighting them.

[0004] The emergence of microLED microdisplay technology has made it possible to miniaturize and increase the resolution of display devices such as augmented reality (AR) display devices, virtual reality (VR) display devices, near-eye displays (NED), and head-up displays (HUD). Summary of the Invention [Problem to be solved by the invention]

[0005] A micro LED microdisplay chip generally includes multiple LED self-emitting units. However, during operation, the light emitted from the LED units is dispersed or there is a lack of wavelength conversion material, resulting in low wavelength conversion efficiency of the wavelength conversion layer in the micro LED microdisplay chip.

[0006] The present invention provides a micro LED micro display chip and a manufacturing method thereof. Hereinafter, various aspects related to the embodiments of the present invention will be described. [Means for solving the problem]

[0007] As a first aspect, a micro LED microdisplay chip is provided, the micro LED microdisplay chip comprising: a driving panel; a plurality of LED units arranged on the driving panel; a fence structure having a plurality of grid holes; and a wavelength conversion layer disposed on the fence structure. The plurality of LED units have a plurality of LED mesas corresponding to each other, each of which can be individually driven by the driving panel. The plurality of grid holes are arranged to surround the plurality of LED mesas, respectively, and recessed areas are formed between the LED mesas and the corresponding grid holes. The wavelength conversion layer includes a first wavelength conversion layer having a plurality of first wavelength conversion units filling the corresponding recessed areas, the LED units emitting first color light, and the first wavelength conversion units converting the first color light into a second color light.

[0008] In one possible implementation, a first filter layer is provided on top of the first wavelength-converting layer, and the first filter layer blocks other colored light and transmits the second colored light.

[0009] In one possible implementation, the wavelength conversion layer further includes a second wavelength conversion layer, the second wavelength conversion layer having a plurality of second wavelength conversion units, the second wavelength conversion units filling the corresponding recessed areas, and the second wavelength conversion units convert the first color light into a third color light.

[0010] In one possible implementation, a second filter layer is provided on the second wavelength-converting layer, and the second filter layer blocks other colored light and transmits the third colored light.

[0011] In one possible implementation, the wavelength conversion layer further includes a third wavelength conversion layer, the third wavelength conversion layer having a plurality of third wavelength conversion units, the third wavelength conversion units filling the corresponding recessed areas, and the third wavelength conversion units convert the first color light into a fourth color light.

[0012] In one possible implementation, a third filter layer is provided on top of the third wavelength-converting layer, and the third filter layer blocks other colored light and transmits the fourth colored light.

[0013] In one possible implementation, the material of the wavelength-converting layer includes wavelength-converting particles and photoresist, and the wavelength-converting particles are phosphors and / or quantum dots.

[0014] In one possible implementation, the top surface of the wavelength conversion layer is flush with or lower than the top surface of the fence structure.

[0015] In one possible implementation, a reflective layer is provided on the surface of the fence structure, said reflective layer being placed on the side walls of the grid holes and on the top surface of the fence structure.

[0016] In one possible implementation, the size of the LED unit is 0.1 to 10 micrometers.

[0017] In a second aspect, a method for manufacturing a micro LED microdisplay chip is provided, the method including: providing a driving panel; forming a plurality of LED units on the driving panel, the plurality of LED units having a plurality of LED mesas corresponding to each other, each of the LED units being individually drivable by the driving panel; forming a fence structure having a plurality of grid holes, the plurality of grid holes surrounding the plurality of LED mesas respectively, with recessed areas formed between the LED mesas and the corresponding grid holes; and forming a wavelength conversion layer on the fence structure, the wavelength conversion layer including a first wavelength conversion layer having a plurality of first wavelength conversion units filling the corresponding recessed areas, the LED units emitting a first color light, and the first wavelength conversion units being used to convert the first color light into a second color light.

[0018] In one possible implementation, forming a wavelength-converting layer on the fence structure includes forming a first wavelength-converting material layer on the fence structure; and exposing and developing the first wavelength-converting material layer using a patterning mask to form the first wavelength-converting layer.

[0019] In one possible implementation, the method further includes forming a first filter layer on the first wavelength conversion layer, the first filter layer being used to block other color lights and transmit the second color light.

[0020] In one possible implementation, the step of forming a wavelength conversion layer on the fence structure includes: forming a second wavelength conversion material layer on the fence structure; and exposing and developing the second wavelength conversion material layer using a patterning mask to form a second wavelength conversion layer, wherein the second wavelength conversion layer has a plurality of second wavelength conversion units, each filling a corresponding one of the recessed areas, and the second wavelength conversion units are used to convert the first color light into a third color light.

[0021] In one possible implementation, the method further includes forming a second filter layer on the second wavelength conversion layer, the second filter layer being used to block other color lights and transmit the third color light.

[0022] In one possible implementation, the step of forming a wavelength conversion layer on the fence structure includes: forming a third wavelength conversion material layer on the fence structure; and exposing and developing the third wavelength conversion material layer using a patterning mask to form a third wavelength conversion layer, the third wavelength conversion layer having a plurality of third wavelength conversion units, each filling a corresponding one of the recessed areas, and the third wavelength conversion units being used to convert the first color light into a fourth color light.

[0023] In one possible implementation, the method further includes forming a third filter layer on the third wavelength conversion layer, the third filter layer blocking other color lights and transmitting the fourth color light.

[0024] In one possible implementation, before forming a wavelength-converting layer on the fence structure, the method further comprises forming a reflective layer on a fence structure surface of the plurality of grid holes.

[0025] In one possible implementation, forming a reflective layer on the surface of the fence structure includes forming a reflective material layer on the plurality of LED mesas and the fence structure, and etching away the reflective material layer on the plurality of LED mesas to form the reflective layer on the sidewalls of the grid holes and the top surface of the fence structure.

[0026] In one possible implementation, the step of forming a plurality of LED units on the driving panel includes the steps of: forming an LED epitaxial layer on the driving panel; and etching the LED epitaxial layer according to a MESA pattern designed by a patterning mask to form the plurality of LED units. [Effects of the Invention]

[0027] A micro LED microdisplay chip according to an embodiment of the present invention includes a plurality of LED units, a fence structure with a plurality of grid holes, and a wavelength conversion layer. The plurality of LED units have a plurality of LED mesas corresponding to each other, and a plurality of grid holes are arranged to surround the plurality of LED mesas, respectively, with recessed areas formed between the LED mesas and the corresponding grid holes. A wavelength conversion layer is disposed on the fence structure, and first wavelength conversion units in the wavelength conversion layer can fill the corresponding recessed areas. On the one hand, in this solution, the first wavelength conversion units directly cover the LED units and fill the corresponding recessed areas, so that the wavelength conversion units are closer to the LED units, effectively utilizing both the light emitted from the light-emitting surface and the side of the LED units, and increasing the amount of wavelength conversion material filled, thereby improving the wavelength conversion efficiency. On the other hand, the fence structure is disposed to surround the LED units, preventing light leakage from the side of the LED units and focusing and shaping the light emitted from the LEDs, further improving the wavelength conversion efficiency of the micro LED microdisplay chip. [Brief explanation of the drawings]

[0028] The above and other objects, features, and advantages of the present invention will become more apparent from a more detailed description of the embodiments of the present invention with reference to the accompanying drawings. The drawings are provided for a better understanding of the embodiments of the present invention, constitute a part of the specification, and, together with the embodiments of the present invention, explain the present invention, but do not limit the present invention. In the drawings, the same reference numerals generally represent the same parts or steps. [Figure 1]1 is a schematic diagram illustrating one possible structure of a micro LED micro display chip according to an embodiment of the present invention; FIG. [Figure 2] 2 is a schematic diagram illustrating another possible structure of the micro-LED micro-display chip shown in FIG. 1. [Figure 3] 1 is a flowchart of a method for manufacturing a micro LED microdisplay chip according to one embodiment of the present invention. [Figure 4] 1 is a structural schematic diagram of a substrate and epitaxial layers according to one embodiment of the present invention. [Figure 5] FIG. 5 is a schematic diagram showing a structure in which a bonding layer is provided on the epitaxial layer shown in FIG. [Figure 6] FIG. 3 is a structural schematic diagram of the driving panel shown in FIG. 2. [Figure 7] FIG. 7 is a schematic diagram showing a structure in which a bonding layer is provided on the drive panel shown in FIG. 6. [Figure 8] FIG. 2 is a schematic diagram showing a structure in which a driving panel and an epitaxial layer are bonded together according to one embodiment of the present invention. [Figure 9] FIG. 9 is a schematic diagram illustrating the structure after the epitaxial layer shown in FIG. 8 has been thinned. [Figure 10] FIG. 10 is a schematic diagram showing the structure of an LED unit obtained by etching the epitaxial layer shown in FIG. [Figure 11] 11 is a schematic diagram showing the structure of a first electrode layer obtained by etching the bonding layer shown in FIG. 10. FIG. [Figure 12] FIG. 12 is a schematic diagram showing a structure in which a passivation layer is provided on the outside of the LED unit shown in FIG. [Figure 13] FIG. 13 is a schematic diagram showing a structure in which a second electrode layer is provided on the top of the LED unit shown in FIG. [Figure 14] FIG. 14 is a schematic diagram showing a structure in which an etching stop layer is provided on the top of the plurality of LED units shown in FIG. [Figure 15] 15 is a schematic diagram showing a structure in which a fence material layer is provided on the etch stop layer shown in FIG. 14. FIG. [Figure 16]16 is a schematic diagram showing the construction of a fence structure having a plurality of grid holes obtained by etching the layer of fence material shown in FIG. 15. FIG. [Figure 17] FIG. 17 is a schematic diagram showing a structure in which a reflective layer is provided on the multiple bowl-shaped fence structures shown in FIG. 16. [Figure 18] FIG. 18 is a schematic diagram showing a structure in which a sacrificial layer is provided on the reflective layer shown in FIG. [Figure 19] FIG. 19 is a schematic diagram showing the structure obtained after removing the sacrificial layer above the grid holes shown in FIG. 18. [Figure 20] FIG. 20 is a schematic diagram showing the structure obtained by etching the reflective layer over the grid holes shown in FIG. 19. [Figure 21] FIG. 21 is a schematic diagram showing the structure obtained after removing the sacrificial layer on the multiple fence structures shown in FIG. 20. [Figure 22] 22 is a schematic diagram showing a structure in which a first wavelength conversion layer is formed on the fence structure shown in FIG. 21. FIG. [Figure 23] 23 is a schematic diagram showing a structure in which a mask layer is provided on the first wavelength conversion layer shown in FIG. 22. FIG. [Figure 24] 24 is a schematic diagram showing a structure obtained by exposing and developing the first wavelength conversion layer shown in FIG. 23. FIG. [Figure 25] 25 is a schematic diagram showing a structure obtained by forming a second wavelength converting unit and a third wavelength converting unit based on FIG. 24. FIG. [Figure 26] FIG. 26 is a schematic diagram showing a structure in which a first filter layer is formed on the wavelength conversion layer shown in FIG. 25. [Figure 27] 27 is a schematic diagram showing a structure in which a mask layer is formed on the first filter layer shown in FIG. 26. FIG. [Figure 28] FIG. 28 is a schematic diagram showing a structure obtained by etching the first filter layer shown in FIG. 27. [Figure 29] FIG. 29 is a schematic diagram showing the structure obtained by removing the mask layer shown in FIG. 28. [Figure 30] 30 is a schematic diagram showing a structure obtained by forming a second filter unit and a third filter unit based on FIG. 29. FIG. [Figure 31]FIG. 31 is a schematic diagram showing the structure of the micro-LED micro-display chip shown in FIG. 30, which does not include a reflective layer. [Figure 32] 1 is a schematic diagram showing the structure of a display device according to one embodiment of the present invention. [Figure 33] 1 is a schematic diagram illustrating the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The solutions according to the embodiments of the present invention will be described below clearly and completely with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments.

[0030] In the description of the present invention, the terms "on," "on top of," "on top of," and "above" should be interpreted in the broadest sense, and descriptions including these terms should be interpreted as including cases where a component is placed on another component in a manner that they are in direct contact with each other, and cases where an intermediate component or layer exists between the components.

[0031] Additionally, for ease of description, the present invention may use spatially relative terms such as "below," "downward," "below," "on," "above," "upper," "lower," "top," etc. to describe the relationship of one element or component to another element or component shown in the figures. In addition to the orientation depicted in the figures, the spatially relative terms are intended to encompass different orientations during use or operation of the device. Equipment may be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein will be interpreted accordingly.

[0032] The term "layer" as used herein refers to a region of material having a certain thickness. A layer may extend across the entire underlying or overlying structure, or may extend over a portion of the underlying or overlying structure. Furthermore, a layer is a region of a homogeneous or heterogeneous continuous structure, the thickness of which is less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure, or any pair of horizontal surfaces therebetween. A layer may extend along horizontal, vertical, and / or conical surfaces.

[0033] Modern society has entered the information age and is developing towards smarter society. Display technology is a key element for realizing information exchange and smarter society.

[0034] In recent years, micro LED has been regarded as the "ultimate display technology" that will revolutionize the industry after LCD and OLED due to its features such as low power consumption, fast response, long life, and high light efficiency, and is the trend and development direction for future display technologies. Many technology giants are stepping up their efforts in this field. Although this field is gaining attention continuously, it cannot be denied that as a new technology with "little experience," there are still many challenges and bottlenecks in achieving high brightness, high resolution, and monolithic full color with micro LED.

[0035] Among the many display technologies currently available, micro LED display technology is widely regarded as a revolutionary next-generation display technology and is attracting widespread attention. Micro LED display technology is a self-luminous display technology that integrates arrayed micrometer-sized LED units (also called LED units) on an active addressing drive panel, which can be individually controlled and lit to output display images.

[0036] Micro LED displays have many advantages, including self-luminous, high efficiency, low power consumption, high integration, and high stability. Furthermore, they are small, flexible, and easy to disassemble and assemble, making them applicable to all current display applications, from small to large sizes.

[0037] Micro LEDs, also known as micro light-emitting diodes, are typically several hundred micrometers in size. The emergence of micro LED microdisplay technology has enabled smaller, higher-resolution display devices, such as augmented reality (AR) display devices, virtual reality (VR) display devices, near-eye displays (NED), and head-up displays (HUD). In these application scenarios, the size of micro LEDs is typically 0.1 to 10 micrometers.

[0038] Micro LED microdisplay chips generally contain multiple LED self-emitting units. However, during operation, the light emitted from the LED units is easily dispersed, or there is a lack of wavelength conversion material, resulting in low wavelength conversion efficiency of the wavelength conversion layer in the micro LED microdisplay chip.

[0039] In view of the above problems, a micro LED microdisplay chip according to an embodiment of the present invention includes a plurality of LED units, a fence structure with a plurality of grid holes, and a wavelength conversion layer. The plurality of LED units respectively have a plurality of corresponding LED mesas, and a plurality of grid holes are arranged to surround the plurality of LED mesas, with recessed areas formed between the LED mesas and the corresponding grid holes. A wavelength conversion layer is disposed on the fence structure, and first wavelength conversion units in the wavelength conversion layer can fill the corresponding recessed areas. On the one hand, in this embodiment, the first wavelength conversion units directly cover the LED units and fill the corresponding recessed areas, so that the wavelength conversion units are closer to the LED units, effectively utilizing both the light emitted from the light-emitting surface and the side surfaces of the LED units. Furthermore, the wavelength conversion efficiency is improved because the wavelength conversion material is increased. On the other hand, the fence structure is disposed to surround the LED units, so that light leakage from the side surfaces of the LED units can be prevented, and the light emitted from the LEDs can be focused and shaped, further improving the wavelength conversion efficiency of the micro LED microdisplay chip.

[0040] 1 is a schematic diagram illustrating one possible cross-sectional structure of a microLED microdisplay chip provided by an embodiment of the present invention. As shown in FIG. 1, the microLED microdisplay chip 100 can include a driving panel 101, a plurality of LED units 102, a fence structure 103 having a plurality of grid holes, and a wavelength conversion layer 116.

[0041] The LED units 102 can be arranged on the driving panel 101 in a regular or irregular pattern and function as pixels of the micro LED microdisplay chip. The LED units 102 can have a number of LED mesas that correspond one-to-one to the LED units 102, and the LED units 102 are also called Micro LED units. The size of the LED units 102 is 0.1 to 10 micrometers, and in a preferred embodiment, the size of the LED units 102 is less than 5 micrometers.

[0042] In some embodiments, the LED unit 102 may be a micro light-emitting diode or a micro organic light-emitting diode, where the micro light-emitting diode is based on an inorganic semiconductor material, such as gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium indium phosphide, etc. The micro organic light-emitting diode is based on an organic material, such as a small molecule, a polymer, a phosphorescent material, etc.

[0043] In some embodiments, the LED unit 102 can emit a first color light, which can include, but is not limited to, any of red light, green light, blue light, yellow light, or ultraviolet light.

[0044] In some embodiments, the LED mesas may have a trapezoidal structure, with inclined sidewalls and an obtuse angle between the sidewalls and the top surface of the LED mesa, thereby improving the light-collecting effect of the LED unit. Alternatively, the LED mesas may have a columnar structure, with a right angle between the sidewalls and the top surface of the LED mesa.

[0045] A fence material layer is further included on top of the plurality of LED units 102. The fence material layer is a fence structure 103 having a plurality of grid holes. The fence structure 103 having a plurality of grid holes includes a plurality of grid holes and the fence structure 103. The plurality of grid holes may be arranged regularly or irregularly. The number of grid holes may be set in a one-to-one correspondence with the plurality of LED units 102. The plurality of grid holes are arranged to surround the plurality of LED mesas, respectively, thereby forming recessed regions between the LED mesas and the corresponding grid holes. The recessed regions may be bowl-shaped or trumpet-shaped. In some embodiments, to improve the light emission uniformity of the LED units 102, the LED units 102 may be arranged at the center positions of the grid holes, thereby allowing the first color light to pass through the grid holes uniformly.

[0046] In some embodiments, the grid holes in the fence material layer may be formed by dry etching, for example, by etching the sidewalls of the grid holes to have inclined surfaces, and the angle between the sidewalls of the grid holes and the top surface of the fence structure may be an obtuse angle. For example, as shown in FIG. 1 , the cross-sectional dimensions of the grid holes may gradually increase along a first direction. Here, the cross-section of the grid holes is a cross-section parallel to the light-emitting surface 106, and generally, this cross-section may be a circular cross-section or a square cross-section, and of course, an irregular cross-section may also be used. The structure of the grid holes may be a bowl-shaped structure or a trumpet-shaped structure, which can align the emitted light of the LEDs.

[0047] In addition, in the embodiment of the present invention, the material of the fence structure 103 having a plurality of grid holes is not particularly limited, and the material of the fence structure 103 having a plurality of grid holes can include, for example, organic resin, organic black matrix photoresist, color filter photoresist, polyimide, etc.

[0048] In some embodiments, the sidewalls of the LED mesa can be slanted to form an obtuse angle between the sidewalls of the LED mesa and the top surface, and the sidewalls of the grid holes can be etched to form an obtuse angle between the sidewalls of the grid holes and the top surface of the fence structure. The combined use of the slanted sidewalls of the LED mesa and the slanted sidewalls of the grid holes as described above allows light to be reflected multiple times on both slanted surfaces, further improving the brightness of the LED unit.

[0049] The wavelength conversion layer 116 is disposed on the fence structure 103. The wavelength conversion layer 116 includes a first wavelength conversion layer 1161, which may include a plurality of first wavelength conversion units 1161a. The first wavelength conversion units 1161a fill corresponding recessed areas. The first wavelength conversion units 1161a may fill at least a portion of the grid holes, or may fill all of the grid holes. The first wavelength conversion units 1161a can convert the first color light emitted from the LED unit 102 into a second color light. Note that the first color light and the second color light are different.

[0050] In some embodiments, the wavelength-converting layers 116 can completely cover the LED units 102. Note that the orthogonal projections of the first wavelength-converting unit 1161a and the LED units 102 may be completely aligned, or the LED units 102 may be located within the orthogonal projection of the first wavelength-converting unit 1161a.

[0051] In some embodiments, having the wavelength conversion layer 116 directly cover the LED unit 102 has several advantages. First, because the wavelength conversion layer 116 surrounds the LED unit 102, the light from both the light-emitting surface and the side surfaces of the LED unit 102 can be effectively utilized, and the light emitted from the LED unit 102 can be more fully utilized. Second, the wavelength conversion layer 116 provides some protection for the LED unit 102 and makes the wavelength conversion layer 116 less likely to fall off, improving yield. Furthermore, the distance between the wavelength conversion layer 116 and the LED unit 102 can be minimized, thereby improving the light conversion efficiency of the micro LED microdisplay chip.

[0052] In some embodiments, the top surface of the wavelength-converting layer 116 may be flush with or lower than the top surface of the fence structure 103. In a preferred embodiment, the top surface of the wavelength-converting layer 116 is flush with the top surface of the fence structure 103, and the flush structure not only effectively prevents optical crosstalk between adjacent LED units 102, but also ensures the flatness and stability of the micro LED microdisplay chip structure, facilitating subsequent manufacturing processes.

[0053] In some embodiments, the size of the LED unit 102 is between 1 and 2 micrometers, and the depth between the top surface of the fence structure 103 and the light-emitting surface of the LED unit 102 is between 2 and 4 micrometers. That is, the depth between the top surface of the fence structure 103 and the light-emitting surface of the LED unit 102 is about 1 to 2 times the size of the LED. This can ensure the light conversion efficiency of the micro LED microdisplay chip and also the light brightness.

[0054] The size of the LED unit 102 refers to the size of the light-emitting surface of the LED unit 102. For example, if the LED unit 102 is a cylinder, the size of the light-emitting surface of the LED unit 102 is the diameter of the cylinder. For another example, if the LED unit 102 is a prism, the size of the light-emitting surface of the LED unit 102 is the length of the side of the prism.

[0055] In some embodiments, the material of the wavelength-converting layer 116 includes wavelength-converting particles and photoresist. The wavelength-converting particles may be, for example, phosphors and / or quantum dots, but embodiments of the present invention are not limited thereto. For example, the quantum dots may be colloidal quantum dots. The wavelength-converting layer 116 can be obtained through an exposure-and-development process, which makes the manufacturing process simpler and easier to control.

[0056] In some embodiments, because the fence structure 103 encases the wavelength conversion layer 116, the wavelength conversion layer 116 does not need to be completely solidified to the bottom (the bottom refers to the bottom closest to the LED units 102) during the exposure process, and the concentration of wavelength conversion particles at the bottom can be increased to improve wavelength conversion efficiency. For example, compared to the prior art solution in which the concentration of wavelength conversion particles is up to 150 mg / ml (about 40%), the concentration of wavelength conversion particles in the present invention can be increased to 300 mg / ml (about 80%), significantly improving the wavelength conversion efficiency of the micro LED microdisplay chip.

[0057] The photoresist in the embodiment of the present invention includes, but is not limited to, overcoat photoresist, SU8 (near-ultraviolet negative photoresist), benzocyclobutene (BCB), etc., and may also be SiO2, Al2O3, Si3N4, etc.

[0058] The phosphor may be yttrium aluminum garnet, cerium phosphor, (oxy)nitride phosphor, silicate phosphor, Mn4+ activated fluoride phosphor, etc. The quantum dots may include one or more combinations of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP, perovskite quantum dots, etc., but are not limited thereto.

[0059] In some embodiments, the first wavelength-converting units 1161a of the wavelength-converting layer 116 are filled into the grid holes, so that the fence structure 103 supports the wavelength-converting layer 116, allowing the wavelength-converting layer 116 to be formed thicker. This can significantly improve the light conversion efficiency. Furthermore, a portion of the side of the wavelength-converting layer 116 is also enclosed by the fence structure 103, increasing the contact area and improving adhesion, thereby improving yield and widening the process window.

[0060] In some embodiments, the wavelength-converting layer 116 may include a first wavelength-converting layer 1161 and a second wavelength-converting layer 1162. The second wavelength-converting layer 1162 may include a plurality of second wavelength-converting units 1162a, each of which fills a different grid hole. That is, the first wavelength-converting unit 1161a fills a corresponding recessed area, which includes some of the grid holes. The second wavelength-converting unit 1162a may fill the remaining corresponding recessed area, which may be all or a portion of the remaining grid holes. The second wavelength-converting unit 1162a may convert the first color light into a third color light.

[0061] In some embodiments, the wavelength-converting layer 116 further includes a third wavelength-converting layer 1163. The third wavelength-converting layer 1163 includes a plurality of third wavelength-converting units 1163a. ​​The first wavelength-converting units 1161a, the second wavelength-converting units 1162a, and the third wavelength-converting units 1163a fill corresponding recessed areas, i.e., fill different grid holes. That is, the first wavelength-converting units 1161a fill some of the grid holes, the second wavelength-converting units 1162a fill some of the remaining grid holes, and the third wavelength-converting units 1163a fill some or all of the remaining grid holes. The third wavelength-converting units 1163a can convert the first color light into a fourth color light.

[0062] The shape, structure, and dimensions of the grid holes of the second wavelength conversion unit 1162a and the third wavelength conversion unit 1163a are similar to those of the first wavelength conversion unit 1161a, and the beneficial effects brought about by the structure are also similar to those of the first wavelength conversion unit 1161a, so they will not be described here again.

[0063] In some embodiments, the material of the first wavelength-converting unit 1161a includes photoresist, quantum dots, and / or phosphors, the material of the second wavelength-converting unit 1162a includes photoresist, quantum dots, and / or phosphors, and the material of the third wavelength-converting unit 1163a includes photoresist, quantum dots, and / or phosphors.

[0064] The first color light, the second color light, the third color light, and the fourth color light are different from each other.

[0065] The wavelengths of the second, third, and fourth colored lights are longer than the wavelength of the first colored light.

[0066] If the first color light is light of a specific wavelength required for the microdisplay to be realized, the wavelength conversion layer corresponding to the light of that wavelength may be omitted. Hereinafter, an example will be described in which the first wavelength conversion layer 1161 is a red wavelength conversion layer, the second wavelength conversion layer 1162 is a green wavelength conversion layer, and the third wavelength conversion layer 1163 is a blue wavelength conversion layer.

[0067] For example, if the first color light emitted by the LED unit 102 is blue light, the first wavelength-converting layer 1161 is a red wavelength-converting layer and the second wavelength-converting layer 1162 is a green wavelength-converting layer, and therefore a corresponding blue wavelength-converting layer is not required.

[0068] As another example, when the first colored light emitted by the LED unit 102 is ultraviolet light, the first wavelength conversion layer 1161 is a red wavelength conversion layer, the second wavelength conversion layer 1162 is a green wavelength conversion layer, and the third wavelength conversion layer 1163 is a blue wavelength conversion layer. Note that, corresponding to the above wavelength conversion layers, the first wavelength conversion unit 1161a is red, the second wavelength conversion unit 1162a is green, and the third wavelength conversion unit 1163a is blue.

[0069] In some embodiments, the first wavelength-converting layer 1161, the second wavelength-converting layer 1162, and the third wavelength-converting layer 1163 each correspond to one of RGB (red, green, blue).

[0070] In some embodiments, a filter layer 117 can further be provided on the wavelength converting layer 116 .

[0071] In some embodiments, materials forming filter layer 117 include, but are not limited to, organic color filter photoresists, Bragg scattering reflectors, and the like.

[0072] In some embodiments, the filter layer 117 can be patterned by any method, including, for example, etching, transfer printing, and the like.

[0073] In some embodiments, the filter layer 117 includes a first filter layer 1171 having a plurality of first filter units 1171b, each of which corresponds to one of the first wavelength-converting units 1161a, and which filters out other colored light and allows the second colored light to pass through.

[0074] In some embodiments, the filter layer 117 may further include a second filter layer 1172, which includes a plurality of second filter units 1172b, each of which corresponds to one second wavelength-converting unit 1162a, and which filters out other colored light and passes a third colored light.

[0075] In some embodiments, the filter layer 117 includes a third filter layer 1173, which includes a plurality of third filter units 1173b, each of which corresponds to one of the third wavelength-converting units 1163a, and which filters out other color lights and passes the fourth color light.

[0076] In some embodiments, each wavelength conversion unit in the wavelength conversion layer 116 can be fabricated sequentially, and then each filter unit in the filter layer 117 can be fabricated. Compared with the prior art method of fabricating wavelength conversion units and filter units alternately, the present invention can ensure the flatness of the structure and is advantageous for the subsequent fabrication of other wavelength conversion units.

[0077] In some embodiments, an etching stop layer 107 may be further provided on the sidewalls and top surface of the LED mesa. The etching stop layer 107 covers the LED units 102 to prevent damage to the LED mesa or the second electrode layer 109 due to etching. The etching stop layer 107 may also transmit light emitted from the LED units 102, so in this case, the etching stop layer 107 must have sufficient transparency. Generally, materials such as silicon dioxide, silicon nitride, and aluminum oxide can be used.

[0078] 1, the etching stop layer 107 has a continuous layer structure, which is located under the fence material layer and over the LED unit, and includes an etching stop layer on the LED mesa and an etching stop layer on the second electrode layer 109.

[0079] In some embodiments, the thickness of the etch stop layer 107 may be, for example, 300-800 nm, but it should be understood that the thickness of the etch stop layer 107 may be selected according to specific circumstances.

[0080] In some embodiments, the etching stop layer 107 may include, for example, an adhesive layer, a blocking layer, etc. The adhesive layer may be made of a metal material with good adhesion, such as chromium Cr, which can improve the adhesion of the etching stop layer 107 and prevent the etching stop layer 107 from peeling off. The blocking layer may be made of a material with stable properties, such as platinum Pt, which does not react with the etching gas, and protects the LED unit 102 from being etched.

[0081] 2 , in some embodiments, a reflective layer 104 may be further provided on the surface of the fence structure 103 having a plurality of grid holes. This reflective layer 104 can not only effectively block light leakage from the sides of the LED units 102, but also reflect the light emitted from the LED units 102. Furthermore, the fence structure 103 provided with the reflective layer 104 can further focus and align the light reflected by the reflective layer 104 and the light emitted from the LED units 102. This can further improve the wavelength conversion efficiency of the wavelength conversion layer 116.

[0082] In some embodiments, the reflective layer 104 can be formed based on the fence structure 103, which can avoid processing at the small spacing between the LED units 102 of the micro LED micro display chip, thereby significantly reducing processing difficulties, widening the process window, and improving processing yield, and is applicable to high resolution and high pixel density products.

[0083] In embodiments of the present invention, the material of the reflective layer 104 is not particularly limited. In some embodiments, the reflective layer 104 can be made of an organic material, and selectable organic materials include, but are not limited to, highly reflective organic paints. The reflective layer 104 can also be made of an inorganic material, and selectable inorganic materials include, but are not limited to, metallic materials such as Al, Cu, and Ag.

[0084] In some embodiments, the reflective layer 104 can be deposited on the surface of the fence structure 103 by methods such as atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, and the like.

[0085] In some embodiments, the reflective layer 104 can be formed by dry etching. Examples of dry etching include, but are not limited to, ion beam etching (IBE) and inductively coupled plasma (ICP) etching. In some embodiments, the reflective layer 104 can be deposited and then blanket-etched using the dry etching method, thereby completely etching and removing the reflective layer 104 from the LED units 102. During the etching process, a plasma redeposition effect occurs on the reflective layer 104, thickening the reflective layer 104 on the sidewalls and enhancing the reflective effect, thereby improving the stability of the fence structure 103 and the overall structure. This further simplifies the manufacturing process and eliminates the need for an additional exposure step to create an etching mask. Furthermore, during the etching process of the reflective layer 104 in the grid holes, the etch stop layer 107 can reduce damage to the LED mesa and second electrode layer 109 caused by the etching process.

[0086] In some embodiments, the surface of the reflective layer 104 can be roughened to form a rough surface. The roughened reflective layer 104 can have improved light reflecting capabilities.

[0087] In the embodiment of the present invention, the method for roughening the reflective layer 104 is not particularly limited, and for example, the reflective layer 104 can be roughened by corrosion. For example, when the reflective layer 104 is made of Al, the reflective layer 104 can be roughened by corrosion using, for example, hydrochloric acid (hydrogen chloride solution).

[0088] In the present embodiment, the surface structure of the reflective layer 104 after roughening is not particularly limited, and the roughened surface of the reflective layer 104 may have an irregular or regular roughness structure. As an example, the roughened surface of the reflective layer 104 may have a polygonal roughness, such as a trapezoidal sawtooth or sawtooth shape. As another example, the roughened surface of the reflective layer 104 may have a curved roughness, such as a wave shape.

[0089] In some embodiments, a passivation layer 105 can be deposited on the sidewalls of the LED unit 102. The material of the passivation layer 105 can include inorganic or organic materials, where the inorganic materials include one or more combinations of SiO2, Al2O3, ZrO2, TiO2, Si3N4, and HfO2. The organic materials can include one or more combinations of black matrix photoresist, color filter photoresist, polyimide, bank photoresist, overcoat photoresist, near-ultraviolet negative photoresist, and benzocyclobutene.

[0090] In some embodiments, the driving panel 101 may include a substrate, a driving circuit, and a plurality of contacts connected to the driving circuit, and the LED units 102 are electrically connected to the plurality of contacts. The driving panel 101 may further include a circuit layer including complementary metal oxide semiconductor (CMOS) elements or TFT elements. These CMOS elements or TFT elements may form the driving circuit. The substrate may be made of a semiconductor material such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, or indium phosphide, or may be made of a non-conductive material such as glass, plastic, or a sapphire wafer.

[0091] In some embodiments, the plurality of contacts include first electrode contacts 110 and second electrode contacts 111, where each of the first electrode contacts 110 can be electrically connected to one LED unit, and the second electrode contacts 111 can be electrically connected to multiple LED units. In this way, any one of the multiple LED units 102 can be individually driven to emit light.

[0092] The first electrode contact 110 may be an anode metal contact, and the second electrode contact 111 may be a cathode metal contact. The first electrode contact 110 is electrically connected to the first electrode layer 108, and the second electrode contact 111 is electrically connected to the second electrode layer 109. The second electrode contact 111 may be a shared electrode contact for multiple LED units 102. The first electrode contact 110 may be independently connected to each LED unit 102. In this embodiment, anode voltages can be applied to the LED units 102 individually through the first electrode contact 110, providing individual driving signals, thereby individually controlling each LED unit to emit light.

[0093] In some embodiments, the connection structure of the LED units 102 may be a shared cathode, a shared anode, or an independent structure. For example, a shared cathode structure may be realized by connecting continuous cathode semiconductor layers. For another example, a shared anode structure or an independent structure may be adopted, as long as the LED units 102 can be individually lit to emit light.

[0094] In some embodiments, there may be another layer, such as an adhesive layer, between the LED unit 102 and the driving panel 101. The LED unit 102 may be glued or bonded to the surface of the driving panel 101 via the adhesive layer.

[0095] In some embodiments, the LED unit 102 includes a first semiconductor layer 1021, a light emitting layer 1022, and a second semiconductor layer 1023, which are sequentially stacked on the driving panel 101. Here, the light emitting layer 1022 and the second semiconductor layer 1023 may be disposed discontinuously, but the bonding layer and the first semiconductor layer 1021 of the plurality of LED units 102 may be disposed continuously, thereby improving the adhesion between the epitaxial structure layer and the driving panel 101 and preventing the epitaxial structure layer from peeling off from the driving panel 101. Of course, the present invention is not limited thereto, and in other embodiments, the bonding layer and the first semiconductor layer 1021 of the plurality of LED units 102 may be disposed discontinuously, which will not be described again here.

[0096] Here, the second semiconductor layer 1023 is an n-type semiconductor layer, and correspondingly, the first semiconductor layer 1021 is a p-type semiconductor layer. The second electrode layer 109 is an n-electrode metal layer, and correspondingly, the first electrode layer 108 is a p-electrode metal layer. The first electrode contact 110 is an anode metal contact, i.e., an anode voltage is applied to the first semiconductor layer 1021. The second electrode contact 111 is a cathode metal contact, i.e., a cathode voltage is applied to the second semiconductor layer 1023. In this way, the light-emitting layer 1022 of the LED unit 102 can be driven to emit light.

[0097] The material of the first electrode layer 108 and the second electrode layer 109 may be indium tin oxide, Cr, Ti, Pt, Au, Al, Cu, Ge, Ni, or the like.

[0098] The first semiconductor layer 1021 may be a p-type semiconductor layer, which may be formed by doping, ion implantation, or other methods. For example, it may be a p-type GaN or InGaN layer, and the first semiconductor layer 1021 may have a multilayer structure. The second semiconductor layer 1023 is an n-type semiconductor layer, which may be formed by doping, ion implantation, or other methods. For example, it may be an n-type GaN or InGaN layer, and the second semiconductor layer 1023 may have a multilayer structure. The light-emitting layer 1022 is a layer in which holes provided by the first semiconductor layer 1021 and electrons provided by the second semiconductor layer 1023 recombine to output light of a specific wavelength. The light-emitting layer 1022 may have a single quantum well structure, a multiple quantum well (MQW) structure, or a structure in which well layers and barrier layers are alternately stacked. The implanted ions may be H+, He+, N+, O+, F+, Mg+, Ar+, or other ions.

[0099] In some embodiments, the first electrode layer 108 may be part of a bonding layer, for example, and the material of the bonding layer may be a conductive material, such as a metal material or a metal alloy material, specifically including Au, Sn, In, Cu, Ti, etc. Of course, the material of the bonding layer may also be a non-conductive material, such as polyimide, polydimethylsiloxane, or SU-8 photoresist, etc. Note that if the material of the bonding layer is a non-conductive material, the bonding layer does not function as an anode together with the first semiconductor layer 1021, and in this case, the first electrode layer 108 can be provided separately.

[0100] It should be noted that the micro LED micro-display chip in this embodiment may further include an encapsulation layer, which may be disposed on the side of the reflective layer 104 that faces away from the driving panel 101 (not shown). In this embodiment, the reflective layer 104 covers the surface of the luminous fence structure 103, and the surface of the reflective layer 104 is uneven according to the fence structure 103. The encapsulation layer can be used to planarize the micro LED micro-display chip, facilitating subsequent processing.

[0101] An embodiment of the device according to the present invention has been described in detail above with reference to Figures 1 and 2. An embodiment of the method according to the present invention will now be described in detail with reference to Figure 3. Note that the description of the embodiment of the method corresponds to the description of the embodiment of the device, so reference can be made to the above-mentioned embodiment of the device for parts not described in detail.

[0102] 3 is a flowchart of a method for manufacturing a micro LED micro-display chip according to one embodiment of the present invention. As shown in FIG. 3, the method for manufacturing a micro LED micro-display chip 300 includes steps S310 to S340.

[0103] In step S310, a driving panel is provided.

[0104] In step S320, a plurality of LED units are formed on the driving panel, each having a plurality of LED mesas in one-to-one correspondence, and each LED unit can be individually driven by the driving panel.

[0105] It should be noted that a substrate may be provided in addition to providing a driving panel, and an LED epitaxial layer may be formed on the substrate.

[0106] In some embodiments, after providing the driving panel, a bonding layer can be formed on the driving panel. The bonding layer is configured to bond the driving panel to the LED epitaxial layer on the substrate. The LED epitaxial layer on the driving panel can then be etched to form multiple LED units. The manufacturing process for multiple LED units will be described in detail later with reference to FIGS. 4 to 31, and therefore will not be described in detail here.

[0107] In step S330, a fence structure is formed having a plurality of grid holes, each of which surrounds a corresponding one of the LED mesas, such that recessed areas are formed between the corresponding grid holes. That is, the LED mesas and the fence structure can jointly form a plurality of recessed areas that correspond one-to-one to the positions of the LED mesas.

[0108] In step S340, a wavelength-converting layer is formed on the fence structure, the wavelength-converting layer including a first wavelength-converting layer having a plurality of first wavelength-converting units filling corresponding recessed areas, the LED units emitting first color light, and the first wavelength-converting units converting the first color light into second color light.

[0109] To better understand the manufacturing method 300 of a micro LED microdisplay chip according to an embodiment of the present invention, the manufacturing method 300 of a micro LED microdisplay chip will be described in detail below with reference to FIGS. 4 to 31.

[0110] 4 to 31 are schematic diagrams illustrating the structure of a micro LED micro-display chip 400 at different stages during the manufacturing process. The micro LED micro-display chip 400 corresponds to the micro LED micro-display chip 100 described above. For details not described in detail in this section, please refer to the description of the micro LED micro-display chip 100.

[0111] In some embodiments, referring to FIG. 4, a substrate 421 may be first provided and an epitaxial layer 422 may be grown on the substrate 421 .

[0112] 5, a bonding layer 424 can be formed on the epitaxial structure layer 422. The bonding layer 424 can be used to bond the LED epitaxial layer 422 on the substrate 421 to the driving panel 401, which will be described later.

[0113] 6, in step S310, a driving panel 401 is provided. The driving panel 401 may include a circuit layer composed of complementary metal-oxide semiconductor (CMOS) elements or thin film transistor (TFT) elements, etc. These CMOS elements or TFT elements form a driving circuit in the driving panel 401. The driving panel 401 may further include a plurality of contacts connected to the driving circuit, and the plurality of LED units 402 are electrically connected to the plurality of contacts. Note that in this embodiment of the present invention, there is no particular limitation on the order in which the substrate 421 and the driving panel 401 are provided.

[0114] In some embodiments, the plurality of contacts include first electrode contacts 410 and second electrode contacts 411, the first electrode contacts 410 are electrically connected to the respective LED units, and the second electrode contacts 411 are electrically connected to the plurality of LED units, so that any one of the plurality of LED units can be individually driven to emit light.

[0115] 7, in some embodiments, a bonding layer 423 can be formed on the driving panel 401. The bonding layer 423 can be used to bond the driving panel 401 and the LED epitaxial layer 422 on the substrate 421.

[0116] In some embodiments, bonding layer 423 and bonding layer 424 can be formed by a deposition method.

[0117] 8 , the LED epitaxial layer 422 on the substrate 421 is inverted, and the bonding layer 423 and the bonding layer 424 are fused together to form the bonding layer 425. This allows the epitaxial layer 422 to be bonded onto the driving panel 401. Then, the substrate 421 is peeled off from the LED epitaxial layer 422. In this manner, the LED epitaxial layer 422 can be formed on the driving panel 401.

[0118] In some embodiments, methods for removing the substrate 421 include, but are not limited to, laser removal, dry etching, wet etching, mechanical polishing, and the like.

[0119] 9, in some embodiments, the inverted LED epitaxial layers 422 may undergo further thinning operations, including dry etching, wet etching, or mechanical polishing.

[0120] 10 , in some embodiments, the LED epitaxial layer 422 can be etched according to a MESA pattern designed by a patterning mask to form an LED unit 402 having a plurality of LED mesas. The LED unit 402 has a functionalized staircase structure, and includes a first semiconductor layer 4021, a light emitting layer 4022, and a second semiconductor layer 4023. The etching can be performed by a dry or wet method.

[0121] In some embodiments, the first semiconductor layer 4021 may be a p-type semiconductor layer, which may be formed by methods such as doping or ion implantation. For example, it may be a p-type GaN or InGaN layer, and the first semiconductor layer 4021 may have a multi-layer structure. The second semiconductor layer 4023 is an n-type semiconductor layer, which may be formed by methods such as doping or ion implantation. For example, it may be an n-type GaN or InGaN layer, and the second semiconductor layer 4023 may have a multi-layer structure. The light emitting layer 4022 is a layer in which holes provided from the first semiconductor layer 4021 and electrons provided from the second semiconductor layer 4023 recombine to output light of a specific wavelength. The light emitting layer 4022 may have a single quantum well structure or a multiple quantum well (MQW) structure, or a structure in which well layers and barrier layers are alternately stacked.

[0122] In some embodiments, the bonding method in the embodiments of the present invention is metal bonding. Referring to Figure 11, the bonding layer 425 can be etched to form a plurality of first electrode layers 408. The plurality of first electrode layers 408 are arranged in one-to-one correspondence with the plurality of LED units 402, and adjacent LED units 402 are not electrically connected through the first electrode layers 408. The first electrode layers 408 are electrically connected to first electrode contacts 410, and a driving circuit in the driving panel 401 can apply anode voltages to the LED units 402 individually through the first electrode contacts 410 to provide individual driving signals. This achieves the purpose of individually controlling the light emission of each LED unit 402.

[0123] In some embodiments, the LED unit 402 can emit a first color light, which can include, but is not limited to, any of red light, green light, blue light, yellow light, or ultraviolet light.

[0124] 12, a passivation layer 405 can be deposited on the sidewall surface of the LED unit 402. The material of the passivation layer 405 can include inorganic or organic materials.

[0125] 13 , in some embodiments, a second electrode layer 409 can be installed between the LED units 402. The second electrode layer 409 is located on the top of the driving panel 401 and is outside the passivation layer 405. The second electrode layer 409 can connect the first semiconductor layers of the multiple LED units 402, and the second electrode layer 409 is a shared cathode electrode layer of the micro LED microdisplay chip. The second electrode contact 411 can be connected to the second electrode layer 409 to form a conductive circuit with the first electrode contact 410, thereby driving the LED unit 402 to emit light.

[0126] The second semiconductor layer 4023 is an n-type semiconductor layer, and the first semiconductor layer 4021 is a p-type semiconductor layer correspondingly. The second electrode layer 409 is an N-pole metal layer, and the first electrode layer 408 is a P-pole metal layer correspondingly.

[0127] Referring to FIG. 14 , in some embodiments, an etch-stop layer 407 can be formed on the sidewalls and top surface of the LED mesa. The etch-stop layer 407 covers the multiple LED units 402 and the second electrode layer 409. As can be seen, the etch-stop layer 407 has a continuous layer structure, including an etch-stop layer on the top of the LED mesa and an etch-stop layer on the top of the second electrode layer 409. The etch-stop layer can prevent etching damage to the LED mesa or the second electrode layer 409. Furthermore, the etch-stop layer 407 may transmit light emitted from the LED units 402. In this case, the etch-stop layer 407 must have sufficient transparency. Commonly, materials such as silicon dioxide, silicon nitride, and aluminum oxide can be used.

[0128] 15, a fence material layer 426 can be formed on top of the plurality of LED units 402. The material of the fence material layer 426 can include organic resin, organic black matrix photoresist, color filter photoresist, polyimide, etc.

[0129] 16 , the fence material layer 426 can be etched to form a fence structure 403 having a plurality of grid holes, each surrounding a corresponding one of the LED mesas, with a recessed area formed between the corresponding grid hole and the corresponding LED mesa. The grid holes are also arranged in one-to-one correspondence with the LED units 402, allowing light emitted from the LED units 402 to pass through the grid holes.

[0130] In some embodiments, the fence material layer 426 is disposed on the etch stop layer 407, and the grid holes of the fence structure 403 can be formed by dry etching, exposing the etch stop layer 407. The etch stop layer 407 covers the top of the LED mesa and the top of the second electrode layer 409, thereby preventing damage to the LED mesa and the second electrode layer 409 during the etching of the grid holes.

[0131] In some embodiments, the sidewalls of the grid holes can be etched to be beveled, and the angle between the sidewalls of the grid holes and the top surface of the fence structure can be an obtuse angle. For example, the cross-sectional dimensions of the grid holes gradually increase along the direction away from the LED unit 402 (the first direction in FIG. 1 ). Here, the cross-section of the grid holes is a cross-section parallel to the light-emitting surface 406, and generally may be a circular cross-section or a square cross-section, although irregular cross-sections are also possible. The shape of the grid holes can be a bowl-shaped structure or a trumpet-shaped structure.

[0132] 17, a reflective material layer may be formed on the LED mesas and the fence structure 403 to improve the reflection effect of the light beams emitted from the LED units 402. The reflective material layer may include a reflective layer 404 on the surface of the fence structure 403 and a reflective layer 412 exposed from the grid holes.

[0133] In some embodiments, a reflective material layer can be deposited on top of the plurality of LED mesas and fence structure 403 by methods such as atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, etc., where the reflective material layer is located on top of the etch stop layer 407.

[0134] In some embodiments, the layer of reflective material on the plurality of LED mesas can be etched away to form a reflective layer 404 on the sidewalls of the grid holes and on the top surface of the fence structure.

[0135] 18 , in some embodiments, before etching away the reflective material layer over the plurality of LED mesas, a sacrificial layer can be further formed on the reflective material layer, including sacrificial layer 413 on top of fence structure 403 and sacrificial layer 414 exposed from top of the grid holes.

[0136] 19, the sacrificial layer 414 exposed from the top of the grid holes may be first removed, temporarily leaving the sacrificial layer 413 on the top of the fence structure 403. The sacrificial layer 413 is provided to protect the reflective layer 404 on the surface of the fence structure 403 of the plurality of grid holes, and prevents the reflective layer 404 on the surface of the fence structure 403 of the plurality of grid holes from being destroyed when etching the reflective layer 412 on the top of the grid holes.

[0137] 20, the reflective layer 412 on the top of the LED mesas can be removed to form the reflective layer 404 by etching the reflective layer 412 on the LED mesas. During the etching of the reflective layer 412, the aforementioned etching stop layer 407 can prevent damage to the LED mesas and the second electrode layer 409 due to etching.

[0138] In some embodiments, dry etching can be used to form the reflective layer 404. Examples of dry etching include, but are not limited to, ion beam etching (IBE), inductively coupled plasma (ICP) etching, etc. In some embodiments, the reflective layer 404 can be blanket-etched after deposition using the dry etching method described above, thereby completely etching the reflective layer 412 on the top of the LED units 402, and also generating a plasma redeposition effect on the reflective layer 404 during the etching process, thickening the reflective layer 404 on the sidewalls, thereby enhancing the reflective effect and improving the stability of the fence structure 403 and the overall structure. This further simplifies the manufacturing process and eliminates the need for an additional exposure step to create an etching mask.

[0139] Referring to Figure 21, after forming the reflective layer 404 on the surface of the fence structure, the remaining sacrificial layer 413 on the fence structure 403 may be removed.

[0140] In some embodiments, forming the wavelength conversion layer 416 on the fence structure 403 includes forming a first wavelength conversion layer 4161, and forming the first wavelength conversion layer 4161 includes forming a first wavelength conversion unit 4161a.

[0141] 22, first, a first wavelength conversion layer 4161 is formed on the fence structure 403. For example, the first wavelength conversion layer 4161 can be formed by spin coating and drying. The material of the first wavelength conversion layer 4161 includes wavelength conversion particles and photoresist, and the wavelength conversion particles may be phosphors and / or quantum dots, etc.

[0142] 23, the region where the first wavelength conversion unit is to be formed is irradiated with light. For example, this can be achieved by shielding other regions using a mask layer 427. For example, ultraviolet light can be used for irradiation under a yellow light environment.

[0143] The mask layer 427 is then removed, and the first wavelength conversion layer 4161 is developed using a developer. Because only the regions of the first wavelength conversion units are solidified by light irradiation, the developer removes the other portions, thereby forming a plurality of first wavelength conversion units 4161a. As shown in FIG. 24 , the first wavelength conversion units 4161a fill at least some or all of the grid holes.

[0144] Similarly, as shown in Fig. 25, multiple second wavelength conversion units 4162a and multiple third wavelength conversion units 4163a can be formed on the fence structure. Note that the first wavelength conversion unit 4161a, the second wavelength conversion unit 4162a, and the third wavelength conversion unit 4163a fill corresponding recessed areas, i.e., fill different grid holes. That is, the first wavelength conversion unit 4161a fills some of the grid holes, the second wavelength conversion unit 4162a fills some of the remaining grid holes, and the third wavelength conversion unit 4163a fills some or all of the remaining grid holes.

[0145] The first wavelength conversion unit 4161a can convert the first color light into the second color light, the second wavelength conversion unit 4162a can convert the first color light into the third color light, and the third wavelength conversion unit 4163a can convert the first color light into the fourth color light.

[0146] In some embodiments, forming the filter layer 417 on the wavelength-converting layer 416 includes forming a first filter unit 4171b.

[0147] 26, a first filter layer 4171 can be formed on the wavelength conversion layer 416. Materials for the first filter layer 4171 include, but are not limited to, organic color filter photoresist, Bragg scattering reflector, and the like.

[0148] 27, a mask layer 428 can be disposed on the first filter layer 4171. Note that the covering area of ​​the mask layer 428 corresponds to the area of ​​the first wavelength conversion unit 4161a.

[0149] 28, the first filter layer 4171 can be etched to remove the filter layer area other than the area covered by the mask layer 428. For example, dry etching or wet etching can be employed.

[0150] 29, the mask layer 428 is removed to form the first filter units 4171b. The first filter units 4171b block other colored light and allow the second colored light to pass. One first filter unit 4171b is disposed corresponding to one first wavelength conversion unit 4161a.

[0151] Similarly, a plurality of second filter units 4172b and a plurality of third filter units 4173b can further be formed.

[0152] In some embodiments, when the reflective layer 404 is installed, the surface of the reflective layer 404 can be further roughened to form a rough surface before the wavelength conversion layer 416 is installed, and the roughened reflective layer 404 can improve its light reflecting ability.

[0153] In the embodiment of the present invention, the method for roughening the reflective layer 404 is not particularly limited, and for example, the reflective layer 404 can be roughened by corrosion. For example, when the reflective layer 404 is made of Al, the reflective layer 404 can be roughened by corrosion using hydrochloric acid (hydrogen chloride solution).

[0154] In some embodiments, the micro LED microdisplay chip may not be provided with a reflective layer 404. That is, after forming the fence structure 403 with a plurality of grid holes, as shown in Figure 31, the first wavelength-converting unit 4161a, the second wavelength-converting unit 4162a and the third wavelength-converting unit 4163a fill the corresponding recessed areas, and then the first filter unit 4171b, the second filter unit 4172b and the third filter unit 4173b are disposed on the first wavelength-converting unit 4161a, the second wavelength-converting unit 4162a and the third wavelength-converting unit 4163a correspondingly to form a new micro LED microdisplay chip structure.

[0155] It should be noted that in the embodiment of the present invention, the order of steps in the method for manufacturing the micro LED micro display chip described above is not particularly limited.

[0156] It should be noted that the embodiments of the manufacturing method of the present invention only describe the manufacturing flow or steps, and for device structures, shapes, materials, etc. that are not described, reference can be made to the above-mentioned embodiments of the micro LED microdisplay chip, and no redundant description will be given here.

[0157] As another possible implementation of the disclosed subject matter, an embodiment of the present invention further provides a display device 3200, as shown in Fig. 32. The display device 3200 includes a micro LED microdisplay chip 3210, which may be the micro LED microdisplay chip according to any of the above-described embodiments. The display device 3200 may be, for example, a component or device including the micro LED microdisplay chip 3210, and may be, for example, a micro LED microdisplay chip device including an encapsulation layer.

[0158] As another possible implementation form of the disclosed subject matter, an embodiment of the present invention further provides an electronic device 3300, as shown in Fig. 33. Note that dashed frames in Fig. 33 indicate that the corresponding units or modules are optional. The electronic device 3300 may include, for example, a micro LED microdisplay chip 3310 or a display device 3200. Here, the micro LED microdisplay chip 3310 is a micro LED microdisplay chip according to any of the above-described embodiments.

[0159] The electronic device 3300 in the present embodiment includes, but is not limited to, display devices such as an augmented reality (AR) display device, a virtual reality (VR) display device, a near-eye display (NED) device, and a head-up display (HUD) device.

[0160] Although specific embodiments of the present invention have been described above, the scope of protection of the present invention is not limited thereto. Any modifications or alternatives that can be easily conceived by those skilled in the art within the disclosed technical scope of the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A micro LED micro display chip, comprising: a drive panel; a plurality of LED units arranged on the drive panel; a fence structure having a plurality of grid holes; and a wavelength conversion layer disposed on the fence structure; The plurality of LED units have a plurality of LED mesas in one-to-one correspondence, and each of the LED units can be individually driven by the driving panel; the plurality of grid holes are provided so as to surround the plurality of LED mesas, respectively, and recessed regions are formed between the LED mesas and the corresponding grid holes; The wavelength-converting layer includes a first wavelength-converting layer having a plurality of first wavelength-converting units, the first wavelength-converting units filling the corresponding recessed areas, the LED units emitting first color light, and the first wavelength-converting units converting the first color light into second color light. A micro LED micro display chip characterized by:

2. a first filter layer provided on the first wavelength conversion layer, the first filter layer blocking other colored light and transmitting the second colored light; 2. The micro LED micro display chip according to claim 1.

3. The wavelength-converting layer further includes a second wavelength-converting layer, the second wavelength-converting layer having a plurality of second wavelength-converting units, the second wavelength-converting units filling the corresponding recessed regions, and the second wavelength-converting units convert the first color light into a third color light.

2. The micro LED micro display chip according to claim 1.

4. A second filter layer is provided on the second wavelength conversion layer, and the second filter layer blocks other colored light and transmits the third colored light.

4. The micro LED micro display chip according to claim 3.

5. The wavelength-converting layer further includes a third wavelength-converting layer, the third wavelength-converting layer having a plurality of third wavelength-converting units, the third wavelength-converting units filling the corresponding recessed regions, and the third wavelength-converting units convert the first color light into a fourth color light.

4. The micro LED micro display chip according to claim 3.

6. a third filter layer is provided on the third wavelength conversion layer, the third filter layer blocking other colored light and transmitting the fourth colored light; 6. The micro LED micro display chip according to claim 5.

7. The material of the wavelength-converting layer includes wavelength-converting particles and photoresist, and the wavelength-converting particles are phosphors and / or quantum dots.

2. The micro LED micro display chip according to claim 1.

8. The top surface of the wavelength-converting layer is flush with or lower than the top surface of the fence structure.

2. The micro LED micro display chip according to claim 1.

9. A reflective layer is provided on the surface of the fence structure, and the reflective layer is disposed on the sidewalls of the grid holes and on the top surface of the fence structure.

2. The micro LED micro display chip according to claim 1.

10. The size of the LED unit is 0.1 to 10 micrometers.

2. The micro LED micro display chip according to claim 1.

11. 1. A method for manufacturing a micro LED microdisplay chip, comprising: providing a drive panel; forming a plurality of LED units on the driving panel, the plurality of LED units having a plurality of LED mesas in one-to-one correspondence, each of the LED units being individually drivable by the driving panel; forming a fence structure having a plurality of grid holes, the plurality of grid holes being disposed to surround the plurality of LED mesas, respectively, and a recessed region being formed between the LED mesa and a corresponding one of the grid holes; forming a wavelength-converting layer on the fence structure, the wavelength-converting layer including a first wavelength-converting layer having a plurality of first wavelength-converting units, the first wavelength-converting units filling the corresponding recessed areas, the LED units emitting first color light, and the first wavelength-converting units used to convert the first color light into a second color light; A method for manufacturing a micro LED micro display chip, comprising:

12. forming a wavelength-converting layer on the fence structure; forming a first wavelength-converting material layer on the fence structure; exposing and developing the first wavelength converting material layer using a patterning mask to form the first wavelength converting layer. The method of claim 11 .

13. The manufacturing method includes: forming a first filter layer on the first wavelength conversion layer; The first filter layer is used to block other colored light and transmit the second colored light. The method of claim 11 .

14. forming a wavelength-converting layer on the fence structure; forming a second wavelength-converting material layer on the fence structure; exposing and developing the second wavelength-converting material layer using a patterning mask to form a second wavelength-converting layer; The second wavelength-converting layer has a plurality of second wavelength-converting units, each of which fills a corresponding one of the recessed regions, and each of the second wavelength-converting units is used to convert the first color light into a third color light. The method of claim 11 .

15. The manufacturing method includes: further comprising forming a second filter layer on the second wavelength conversion layer; The second filter layer is used to block other colored light and transmit the third colored light. The method of claim 14 .

16. forming a wavelength-converting layer on the fence structure; forming a third wavelength-converting material layer on the fence structure; exposing and developing the third wavelength converting material layer using a patterning mask to form a third wavelength converting layer; The third wavelength-converting layer has a plurality of third wavelength-converting units, each of which fills a corresponding one of the recessed regions, and each of the third wavelength-converting units is used to convert the first color light into a fourth color light. The method of claim 14 .

17. The manufacturing method further comprising forming a third filter layer on the third wavelength conversion layer; The third filter layer blocks other colored light and transmits the fourth colored light. The method of claim 16 .

18. Before forming a wavelength-converting layer on the fence structure, the manufacturing method further comprises: forming a reflective layer on the fence structure surface of the plurality of grid holes. The method of claim 11 .

19. Forming a reflective layer on the surface of the fence structure includes: forming a reflective material layer over the plurality of LED mesas and the fence structure; and etching away the reflective material layer on the plurality of LED mesas to form the reflective layer on the sidewalls of the grid holes and on the top surface of the fence structure.

20. The method of claim 18.

20. forming a plurality of LED units on the driving panel, forming an LED epitaxial layer on the driving panel; Etching the LED epitaxial layer according to a MESA pattern designed by a patterning mask to form the plurality of LED units. The method of claim 11 .

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