Micro-LED light-emitting module with micro-lens structure and preparation method of Micro-LED light-emitting module

Abstract

The invention provides a Micro-LED light-emitting module with a micro-lens structure and a preparation method thereof, and relates to the field of display chips, and the method comprises the steps: obtaining a light-emitting semiconductor layer pixel array and a bonding metal layer array; filling spacer regions among the pixel arrays of the light-emitting semiconductor layer to form a whole-surface passivation layer, polishing the whole-surface passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer, etching the whole-surface passivation layer to obtain a passivation layer, and evaporating a netted N-type electrode layer on the N-type semiconductor layer; sequentially spin-coating a first layer of spin-coated glass, a second layer of spin-coated glass and a positive photoresist on the N-type electrode layer, the passivation layer and the whole passivation layer to obtain a positive photoresist dot array; and performing hot melting backflow on the positive photoresist dot array to obtain a micro lens template layer, and performing dry etching to inherit the micro lens template layer into the first layer of spin-coated glass and the second layer of spin-coated glass to obtain the double-layer spin-coated glass micro lens array. According to the invention, the uniformity and repeatability of the product preparation process and the bonding wire yield of packaging are improved.

Description

Technical Field

[0001] This invention relates to the field of display chip technology, and in particular to a microlens structure Micro-LED light-emitting module and its fabrication method. Background Technology

[0002] Micro-LED light-emitting modules are typically integrated from Micro-LED chips and a driving substrate (CMOS substrate). With its core advantages such as self-emission, high brightness, high contrast, low power consumption, long lifespan, ultra-high PPI (Pixels Per Inch), and excellent miniaturization capabilities, Micro-LED is widely considered by the industry to be the most promising next-generation display technology. It is seen as a key direction for breaking through the bottlenecks of existing LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode) technologies, and has a particularly promising future in fields pursuing ultimate display effects.

[0003] As the requirements for resolution and miniaturization of display devices increase day by day, the size of Micro-LED micro-display chips continues to shrink. When Micro-LED pixels reach the micrometer scale (≤20μm), the size effect gradually becomes significant. Due to the existence of total internal reflection, its light extraction efficiency drops sharply.

[0004] Meanwhile, the light emission spatial distribution of Micro-LED chips exhibits a Lambertian-like distribution, with a divergence angle reaching 120° or even greater. This large divergence angle not only introduces severe optical crosstalk, leading to decreased color saturation and blurred image edges, but may also cause unwanted "halo" or "fog" effects when displaying dark scenes, severely damaging the purity of the image and the visual experience. The higher the pixel density and the smaller the spacing, the more prominent the crosstalk problem becomes. Moreover, the optical waveguide systems of near-eye display devices such as AR and VR can only collect light within a range of ±5 to ±30° from the near normal to enter the device. The Lambertian-distributed light emission distribution of Micro-LEDs implies extremely low optical coupling efficiency and huge energy loss.

[0005] To improve the light extraction efficiency and collimation of Micro-LED microdisplay chips, microlens array structures are often integrated onto their surfaces. Current microlens array integration processes typically involve spin-coating transparent photoresist or depositing transparent oxide as the microlens material, then fabricating a microlens template on its surface using photoresist, and finally transferring the microlens template into the microlens material using dry etching. This process has the following problems: (1) When photoresist is used as a microlens material, it is prone to aging. Moreover, during spin coating, the working surface is often a composite, non-planar surface composed of metal, passivation layer, semiconductor layer and driving substrate surface, which is not conducive to the uniformity and repeatability of spin coating. Transparent oxide as a microlens material has a more complex preparation process and higher cost. (2) If dry etching is used to integrate microlens arrays, the exposure of pads during or after etching must be considered. Due to the certain load effect of dry etching, and the fact that the pad area is often lower than the pixel area, the amount of dielectric layer deposited or spin-coated is greater than that of the pixel area itself. These factors make it impossible to completely remove the dielectric layer on the surface of the pads after dry etching, which affects the yield of subsequent bonding wires. (3) In order to remove the dielectric layer residue on the surface of the pad, if photoresist is used as the microlens material, the pad can be exposed in advance by photolithography. However, in the dry etching process, excessive etching time will introduce new pad etching damage and affect the subsequent yield. (4) The top layer metal on the electrodes and pads is often an inert metal such as Au. However, the bonding strength between spin-coated glass and inert metal is very low. It is very easy to crack and fall off during the process, which is also not conducive to the stability of the device and makes it prone to failure.

[0006] Therefore, existing methods for fabricating microlens array structures integrated on the surface of Micro-LEDs urgently need to improve the uniformity, repeatability, and bonding yield of the product fabrication process. Summary of the Invention

[0007] Based on this, the purpose of this invention is to provide a microlens structure Micro-LED light-emitting module and its preparation method, which can improve the uniformity, repeatability and bonding yield of current product preparation processes.

[0008] This invention provides a method for fabricating a microlens structure Micro-LED light-emitting module, comprising obtaining a light-emitting semiconductor layer and a driving module, wherein the driving module includes a driving substrate metal layer, the driving substrate metal layer including a positive electrode metal bump array, and the method further comprising: A bonding metal layer is obtained, and the light-emitting semiconductor layer and the positive electrode metal bump array are bonded together through the bonding metal layer to bond and drive the module; the light-emitting semiconductor layer and the bonding metal layer are separated to obtain a light-emitting semiconductor layer pixel array and a bonding metal layer array that correspond one-to-one with the positive electrode metal bump array. A passivation layer is formed by filling the gap between the pixel array of the light-emitting semiconductor layer with spin-coated glass, polishing the passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer, etching the passivation layer to obtain the passivation layer, and evaporating a mesh-like N-type electrode layer in the N-type semiconductor layer. A first spin-coated glass layer, a second spin-coated glass layer, and a positive photoresist are sequentially spin-coated onto the N-type electrode layer, the passivation layer, and the entire passivation layer. After photolithography and development, a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array is obtained. A hot-melt reflow of positive photoresist dots is used to obtain a microlens template layer with a spherical cap morphology. Dry etching is then used to transfer the microlens template layer to the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array.

[0009] In addition, the microlens structure Micro-LED light-emitting module fabrication method of the present invention described above may also have the following additional technical features: Further, the steps of sequentially spin-coating a first layer of spin-coated glass, a second layer of spin-coated glass, and positive photoresist onto the N-type electrode layer, the passivation layer, and the entire passivation layer, and obtaining a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array after photolithography and development include: A first layer of spin-coated glass is spin-coated onto the N-type electrode layer, the passivation layer, and the entire passivation layer, and then cured. Then, a second spin-coated glass layer is spin-coated on the first spin-coated glass layer, and photolithography is performed to expose the first spin-coated glass layer above the pad metal layer. The layer is then cured. The second spin-coated glass layer is a photosensitive spin-coated glass. Then, positive photoresist is spin-coated onto the surface of the second spin-coated glass layer. After photolithography and development of the positive photoresist, a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array is obtained. The step of spin-coating a first layer of spin-coated glass onto the N-type electrode layer, the passivation layer, and the entire passivation layer includes the following method for spin-coating the first layer of spin-coated glass onto the N-type electrode layer: A layer of easily oxidizable metal is evaporated on the surface of the N-type electrode layer to oxidize the surface and obtain an adhesive layer. The adhesive layer is used to bond the metal and spin-coated glass to transform the original inert metal-spin-coated glass interface on the surface of the N-type electrode layer into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass. The material of the N-type electrode layer is one or more combinations of Cr, Au, Pt, Ni, Al, and Ti; The top metal material of the N-type electrode layer is one or more combinations of Ti, Cr, Ni, and Al; the method of oxidizing the top metal of the N-type electrode layer is one or more combinations of static natural oxidation, ICP oxygen ion bombardment, and peroxide oxidation.

[0010] Furthermore, in the step of dry etching to inherit the microlens template layer into the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array: ICP dry etching was used with an upper electrode of 330W and a lower electrode of 180W. The etching atmosphere included Cl2 and BCl3, and the etching time was 600s. This yielded a double-layer spin-coated glass microlens array consisting of the first and second spin-coated glass layers after etching.

[0011] Furthermore, the etching selectivity ratios of the first spin-coated glass layer and the second spin-coated glass layer to the positive photoresist are 1, respectively.

[0012] Furthermore, in the step of dry etching to inherit the microlens template layer into the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array: ICP dry etching was used with an upper electrode of 200W and a lower electrode of 35W. The etching atmosphere included CF4 and CH4, and the etching time was 600s. This yielded a double-layer spin-coated glass microlens array consisting of a first layer of spin-coated glass and a second layer of spin-coated glass after etching.

[0013] Furthermore, the etching selectivity ratio of the first spin-coated glass layer to the positive photoresist and the etching selectivity ratio of the second spin-coated glass layer to the positive photoresist both include 1.8.

[0014] Furthermore, the driving module also includes a driving substrate, wherein a metal layer is disposed on the driving substrate, in the step of hot-melt reflow of positive photoresist dot array to obtain a microlens template layer with a spherical cap morphology: The driving substrate is placed on a baking tray and placed in a forced-air oven. It is heated to 165℃-175℃ and maintained for 5min-120min to allow the positive photoresist dot array to reach the glass transition temperature so that it becomes fluid. Under the action of surface tension, a microlens template layer with a spherical cap morphology is formed.

[0015] Furthermore, the driving substrate metal layer further includes a pad metal layer and an annular metal layer, wherein the pad metal layer, the annular metal layer, and the positive electrode metal bump array are stacked sequentially and correspond one-to-one. The steps of polishing the entire passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer, etching the entire passivation layer to obtain the passivation layer, and evaporating a mesh-like N-type electrode layer in the N-type semiconductor layer include: Polish the entire passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer; Etching removes the entire passivation layer on the surface of the pad metal layer and the annular metal layer to obtain the passivation layer; A mesh-like N-type electrode layer is evaporated in the N-type semiconductor layer, the ring metal layer, and the pad metal layer.

[0016] Furthermore, the steps of bonding the light-emitting semiconductor layer and the positive electrode metal bump array together by bonding a bonding metal layer, and separating the light-emitting semiconductor layer and the bonding metal layer to obtain a light-emitting semiconductor layer pixel array and a bonding metal layer array that correspond one-to-one with the positive electrode metal bump array, include: A bonding metal layer is deposited over the entire surface of the light-emitting semiconductor layer on a silicon substrate, and the bonding metal layer is bonded to the positive electrode metal bump array; The silicon substrate is removed to obtain the light-emitting semiconductor layer. The light-emitting semiconductor layer is then divided to form a light-emitting semiconductor layer pixel array. The light-emitting semiconductor layer pixel array corresponds one-to-one with the positive electrode metal bump array. The bonding metal layers are separated to form a bonding metal layer array that corresponds one-to-one with the positive electrode metal bump array.

[0017] Another aspect of the present invention provides a microlens structure Micro-LED light-emitting module, including a driving module and a light-emitting module. The light-emitting module includes a plurality of light-emitting semiconductor layer pixel units to form a light-emitting semiconductor layer pixel array. The driving module includes a driving substrate metal layer and is connected to the light-emitting semiconductor layer pixel array. The light-emitting module further includes multiple bonding metal layers to form a bonding metal layer array, wherein the bonding metal layer array corresponds one-to-one with the light-emitting semiconductor layer pixel array and connects the driving substrate metal layer and the light-emitting semiconductor layer pixel array; The light-emitting module further includes a first spin-coated glass layer, an N-type electrode layer, and a full-surface passivation layer. The first spin-coated glass layer is disposed above the light-emitting semiconductor layer pixel unit. The N-type electrode layer is disposed between the first spin-coated glass layer and the light-emitting semiconductor layer pixel unit and connects to the light-emitting semiconductor layer pixel unit. The light-emitting module further includes a plurality of second spin-coated glass layers to form a second spin-coated glass array. The second spin-coated glass layers are disposed above the first spin-coated glass layer. The passivation layer is disposed between the driving module and the first spin-coated glass layer to fill the gap between two adjacent light-emitting semiconductor layer pixel units and is flush with the upper surface of the light-emitting semiconductor layer pixel array to form a flat surface. One end of the bonding metal layer is disposed on the flat surface.

[0018] The aforementioned microlens structure Micro-LED light-emitting module and its fabrication method, by adopting a double-layer spin-coated glass microlens structure, offers several advantages. Firstly, compared to simply depositing transparent materials, the process is simpler, which is beneficial for improving the uniformity of the product fabrication process and increasing product yield. Secondly, compared to pure spin-coating photoresist, the silicon dioxide-like material of the spin-coated glass has better stability, improving the bonding wire yield of the encapsulation. Furthermore, the first layer of spin-coated glass serves as the bottom layer for spin-coating the microlens material, spin-coating it onto the N-type electrode layer, passivation layer, and the entire passivation layer to process the complex and non-planar surface into a unified surface composed of only one material, achieving local planarization. This provides a unified surface for spin-coating the second layer of spin-coated glass, which is beneficial for the uniformity and repeatability of spin-coating the second layer of spin-coated glass, and helps improve the product yield for large-scale production. Secondly, a second layer of spin-coated glass is spin-coated onto the surface of the first layer of spin-coated glass. Photolithography is used to expose the pad area so that a dielectric layer film exists on the surface of the pad. This film is thinner than the dielectric layer in the pixel area. This allows the pads to be protected from over-etching at the beginning of the dry etching process. At the end of the dry etching process, the dielectric layer on the surface of the pad can be removed simultaneously. This eliminates the need to photolithographically etch and etch the pads again in subsequent steps for wire bonding, resulting in shorter process steps and more efficient production. Furthermore, this invention involves evaporating an easily oxidizable metal layer onto the surface of the N-type electrode layer. This oxidized metal then serves as the bonding layer between the metal and the spin-coated glass, transforming the original inert metal-spin-coated glass interface into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass. The layers are bonded together by stronger chemical bonds. This structure ensures that the spin-coated glass remains structurally stable during production and use, preventing cracking or peeling from the electrode and pad surfaces. Simultaneously, the process does not require additional photolithography steps. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the silicon substrate light-emitting semiconductor layer in the first embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the metal bonding layer after evaporation, photolithography, and peeling of the silicon substrate light-emitting semiconductor layer in the first embodiment of the present invention; Figure 3 This is a schematic diagram of the structure after the silicon substrate light-emitting semiconductor layer and the driving module are bonded in the first embodiment of the present invention; Figure 4 This is a schematic diagram of the structure after the semiconductor layer and the driving module are bonded together, after the silicon substrate is removed, in the first embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the pixel array of the light-emitting semiconductor layer formed by separating the light-emitting semiconductor layer in the first embodiment of the present invention; Figure 6This is a schematic diagram of the chip bonding metal layer array in the first embodiment of the present invention, which is a one-to-one correspondence between the chip bonding metal layer formation and the positive electrode metal bump array of the driving substrate. Figure 7 This is a schematic diagram of the structure after preparing the entire passivation layer in the first embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of the passivation layer prepared after exposing the annular metal layer and the pad metal layer covered by the entire passivation layer in the first embodiment of the present invention. Figure 9 This is a schematic diagram of the structure after preparing the N-type electrode layer and oxidizing the top metal of the N-type electrode layer in the first embodiment of the present invention; Figure 10 This is a schematic diagram of the structure after the preparation of a first layer of spin-coated glass and a second layer of spin-coated glass in the first embodiment of the present invention, and after photolithography and development of the second layer of spin-coated glass, and then spin-coating positive photoresist and completing photolithography and development. Figure 11 This is a schematic diagram of the structure formed by hot melting and reflowing positive photoresist to create a spherical cap morphology in the first embodiment of the present invention; Figure 12 This is a schematic diagram of a semi-ellipsoidal double-layer spin-coated glass microlens array obtained by using dry etching to transfer a microlens template layer with a spherical morphology to the first and second spin-coated glass layers in the first embodiment of the present invention. Figure 13 This is a schematic diagram showing the positions of the driving substrate pad metal layer, the positive electrode metal bump array, and the annular metal layer in the first embodiment of the present invention. Figure 14 This is a schematic diagram of a hemispherical double-layer spin-coated glass microlens array obtained by using dry etching to transfer the microlens template layer with a spherical morphology to the first and second spin-coated glass layers in the second embodiment of the present invention. Figure 15 This is a schematic diagram of the structure after the passivation layer is prepared in the third embodiment of the present invention; Figure 16 This is a schematic diagram of the structure of the N-type electrode layer after oxidation of the top metal of the N-type electrode layer in the third embodiment of the present invention. Figure 17 This is a schematic diagram of the structure after the preparation of the first spin-coated glass layer and the second spin-coated glass layer in the third embodiment of the present invention, the completion of photolithography and development of the second spin-coated glass layer, and the spin-coating of positive photoresist and the completion of photolithography and development. Figure 18 This is a schematic diagram of the structure of the microlens template layer in the third embodiment of the present invention, which is formed by hot melting and reflowing photoresist to create a spherical cap morphology and corresponds one-to-one with the positive metal bump array of the dot matrix driving substrate. Figure 19This is a schematic diagram of a semi-ellipsoidal double-layer spin-coated glass microlens array that encloses the light-emitting semiconductor layer pixel array, obtained by dry etching of a microlens template layer with a spherical morphology to the first and second spin-coated glass layers in the third embodiment of the present invention. Explanation of key component symbols:

[0020] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] To improve the uniformity, repeatability, and bonding yield of current product fabrication processes, this application provides a microlens-structured Micro-LED light-emitting module and its fabrication method. On one hand, this effectively improves the light extraction efficiency of Micro-LED chips while reducing the beam angle, lowering optical crosstalk, and improving the optical coupling efficiency of AR / VR devices. On the other hand, integrating a double-layer spin-coated glass microlens using the microlens-structured Micro-LED light-emitting module fabrication method provided in this application can further improve the uniformity, repeatability, and bonding yield of the product fabrication process. Specifically: This application employs a microlens structure with a double-layer spin-coated glass. On one hand, compared to simply depositing transparent materials, the process is simpler, which is beneficial for improving the uniformity of the product preparation process and the product yield. On the other hand, compared to pure spin-coating photoresist, the silicon dioxide-like material of the spin-coated glass has better stability, improving the bonding wire yield of the encapsulation. Furthermore, the first layer of spin-coated glass serves as the bottom layer for spin-coating the microlens material, and is spin-coated onto the N-type electrode layer, passivation layer, and the entire passivation layer to process the complex and non-planar surface into a uniform surface composed of only one material, achieving local planarization. This provides a uniform surface for spin-coating the second layer of spin-coated glass, which is beneficial for the uniformity and repeatability of spin-coating the second layer of spin-coated glass, and helps to improve the product yield of large-scale production. Secondly, a second layer of spin-coated glass is spin-coated onto the surface of the first layer of spin-coated glass. Photolithography is used to expose the pad area so that a dielectric layer film exists on the surface of the pad. This film is thinner than the dielectric layer in the pixel area. This allows the pads to be protected from over-etching at the beginning of the dry etching process. At the end of the dry etching process, the dielectric layer on the surface of the pad can be removed simultaneously. This eliminates the need to photolithographically etch and etch the pads again in subsequent steps for wire bonding, resulting in shorter process steps and more efficient production. Furthermore, this invention involves evaporating an easily oxidizable metal layer onto the surface of the N-type electrode layer. This oxidized metal then serves as the bonding layer between the metal and the spin-coated glass, transforming the original inert metal-spin-coated glass interface into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass. The layers are bonded together by stronger chemical bonds. This structure ensures that the spin-coated glass remains structurally stable during production and use, preventing cracking or peeling from the electrode and pad surfaces. Simultaneously, the process does not require additional photolithography steps.

[0024] To facilitate understanding of the present invention, several embodiments are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0025] Example 1 The method for fabricating a microlens structure Micro-LED light-emitting module in the first embodiment of the present invention includes steps S101 to S108: S101. Obtain a silicon substrate light-emitting semiconductor layer, a bonding metal layer and a driving module. The driving module includes a driving substrate metal layer, which includes a positive electrode metal bump array. A bonding metal layer is deposited on the entire surface of the silicon substrate light-emitting semiconductor layer, and the bonding metal layer is bonded to the positive electrode metal bump array.

[0026] like Figure 1 The silicon substrate light-emitting semiconductor layer 100 shown includes a silicon substrate 101, an N-type semiconductor layer 102, an active semiconductor layer 103, and a P-type semiconductor layer 104. A metal layer 105 is directly evaporated and bonded to the surface of the P-type semiconductor layer 104, such as... Figure 2 As shown, the bonding metal layer 105 is a Ni / Au bilayer metal with thicknesses of 0.1 nm and 500 nm, respectively.

[0027] like Figure 3 As shown, the bonding metal layer 105 and the positive electrode metal bump array 205 of the driving substrate metal layer 210 are bonded using a bonding machine. The bonding pressure is 6000 kg, the bonding temperature is 360 °C, and the bonding time is 1800 s. The total thickness of the driving module 200 is approximately 730 μm. Figure 3 As shown, the drive module 200 includes a drive substrate 201, a control unit 202, and a drive substrate metal layer 210, wherein, as Figure 13 As shown, the driving substrate metal layer 210 includes a pad metal layer 203, an annular metal layer 204, and a positive electrode metal bump array 205.

[0028] S102. Remove the silicon substrate of the light-emitting semiconductor layer to obtain the light-emitting semiconductor layer, divide the light-emitting semiconductor layer to form a light-emitting semiconductor layer pixel array, and the light-emitting semiconductor layer pixel array corresponds one-to-one with the positive electrode metal bump array.

[0029] like Figure 4 As shown, the silicon substrate 101 in the silicon substrate light-emitting semiconductor layer 100 structure is removed. The specific steps are as follows: mechanical grinding is used to thin the silicon substrate light-emitting semiconductor layer 100 and the driving module 200 to a total thickness of 800 μm. Then, CMP polishing is used to remove the remaining silicon substrate 101, thereby obtaining a light-emitting semiconductor layer 110 including an N-type semiconductor layer 102, an active semiconductor layer 103, and a P-type semiconductor layer 104.

[0030] S103, Separate bonding metal layers form a bonding metal layer array that corresponds one-to-one with the positive electrode metal bump array.

[0031] like Figure 5 As shown, 5312 positive photoresist is spin-coated. After photolithography and development, the 5312 positive photoresist dots are aligned one-to-one with the positive electrode metal bump array 205. Hot phosphoric acid is used at 150°C for 8 minutes for etching. Then, ICP dry etching is used to remove the 5312 positive photoresist by oxygen ion bombardment. This separates the light-emitting semiconductor layer 110 to form the light-emitting semiconductor layer pixel array 120. The light-emitting semiconductor layer pixel array 120 is aligned one-to-one with the positive electrode metal bump array 205. The diameter of a single pixel in the light-emitting semiconductor layer pixel array 120 is 1.5μm-2.5μm.

[0032] like Figure 6 As shown, the bonding metal layer 105 is etched using a BOE solution (i.e., a buffered oxide etching solution, which is a mixture of hydrofluoric acid and ammonium fluoride, wherein the volume ratio of 49% hydrofluoric acid aqueous solution to 40% ammonium fluoride aqueous solution is 1:6) to separate the bonding metal layer 105 and form a bonding metal layer array 115 corresponding one-to-one with the driving substrate metal layer 210.

[0033] S104. The space between the pixel array of the light-emitting semiconductor layer is filled by spin-coating glass to form a passivation layer on the whole surface. The passivation layer on the whole surface is polished to expose the N-type semiconductor layer in the light-emitting semiconductor layer. The passivation layer on the surface of the pad metal layer and the ring metal layer is etched away to obtain the passivation layer.

[0034] like Figure 7 As shown, firstly, a SiNx layer with a thickness of 200 nm is deposited on the surface of the driving module 200 using PECVD. Then, spin-coated glass is used to fill the spacing region 106 between the light-emitting semiconductor layer pixel array. Finally, CMP is used to polish the spin-coated glass to expose the N-type semiconductor layer 102, resulting in an insulating, full-surface passivation layer 116. In some optional embodiments, the full-surface passivation layer 116 is one or more combinations of SiNx, SiO2, and spin-coated glass.

[0035] like Figure 8 As shown, firstly, 5312 positive photoresist is spin-coated. After photolithography and development, 5312 positive photoresist is used to protect the area except for the annular metal layer 204 and the pad metal layer 203. Then, ICP dry etching is used to etch away the entire passivation layer 116 on the surface of the pad metal layer 203 and the annular metal layer 204 to obtain the passivation layer 126.

[0036] S105. An N-type electrode layer in the form of a mesh is evaporated in the N-type semiconductor layer, the ring metal layer and the pad metal layer by a stripping photolithography process.

[0037] like Figure 9 As shown, using a lift-off photolithography process, a mesh-like N-type electrode layer 107 is evaporated onto the N-type semiconductor layer 102 and the annular metal layer 204 to form an electrical connection with a shared N-electrode structure. This enables a control method where the illumination is controlled by the positive electrode metal bump array 205. Simultaneously, the N-type electrode layer 107 is also evaporated onto the pad metal layer 203. The N-type electrode layer 107 is a multilayer metal structure. Starting from the layer directly in contact with the N-type semiconductor layer 102, each layer has an Al / Ti / Au / Ti structure with thicknesses of 10nm / 50nm / 200nm / 5nm. Then, ICP dry etching is used to bombard the Ti metal surface with oxygen ions to form a layer of titanium oxide. It should be further noted that the material of the N-type electrode layer 107 is one or more combinations of Cr, Au, Pt, Ni, Al, and Ti. The top metal material of the N-type electrode layer 107 is one or more combinations of Ti, Cr, Ni, and Al. Furthermore, the method for oxidizing the top metal of the N-type electrode layer is one or a combination of static natural oxidation, ICP oxygen ion bombardment, and peroxide oxidation.

[0038] S106. A first spin-coated glass layer, a second spin-coated glass layer, and a positive photoresist are sequentially spin-coated onto the N-type electrode layer, the passivation layer, and the entire passivation layer. After photolithography and development, a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array is obtained.

[0039] like Figure 10As shown, firstly, a first layer of spin-coated glass 401 is spin-coated onto the N-type electrode layer 107, the passivation layer 126, and the entire passivation layer 116, and then cured. Specifically, a layer of easily oxidizable metal is evaporated on the surface of the N-type electrode layer to oxidize the surface and obtain an adhesive layer. The adhesive layer is used to bond the metal and the spin-coated glass, so as to transform the original inert metal-spin-coated glass interface on the surface of the N-type electrode layer into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass.

[0040] Then, a second photosensitive spin-coated glass layer 402 is spin-coated, and photolithography and development are performed to expose the first spin-coated glass layer 401 above the pad metal layer 203, followed by curing. Next, 5312 positive photoresist is spin-coated onto the surface of the second spin-coated glass layer. After photolithography and development, a 5312 positive photoresist dot array 403 is obtained, corresponding one-to-one with the positive electrode metal bump array 205 of the driving substrate. The size of a single dot in the 5312 positive photoresist dot array 403 is 2.8μm-3.2μm, and the shape is square. The use of photosensitive spin-coated glass as the second spin-coated glass facilitates the opening of the pads on the second spin-coated glass.

[0041] It should be further explained that the thickness of the first and second spin-coated glass layers is designed to ensure that, with the expected total thickness of the spin-coated glass, the first spin-coated glass layer on top of the pad metal layer can protect the pads for a period of time during the initial dry etching process, and only ensures that the first spin-coated glass layer on top of the pad metal layer can be completely removed before the final etching is completed.

[0042] This invention involves evaporating a layer of easily oxidizable metal onto the surface of the N-type electrode layer and the pad metal layer. After oxidation, this surface serves as a bonding layer between the metal and the spin-coated glass, transforming the original inert metal-spin-coated glass interface into a multi-layered structure of inert metal-active metal-metal oxide-spin-coated glass. The layers are bonded together by stronger chemical bonds. This structure ensures that the spin-coated glass remains structurally stable during production and use, preventing cracking or peeling from the electrode and pad surfaces. Furthermore, the process does not require additional photolithography steps.

[0043] S107. Hot melt reflow of positive photoresist dot array to obtain a microlens template layer with a spherical cap morphology.

[0044] like Figure 11 As shown, using a forced-air oven, the drive module 200 is placed on a baking tray and placed in the forced-air oven, heated to 167°C and maintained for 120 minutes, so that the 5312 positive photoresist dot array 403 reaches the glass transition temperature to have a certain fluidity. Under the action of surface tension, a microlens template layer with a spherical cap morphology is formed. In this embodiment, a hemispherical microlens template layer 404 is formed.

[0045] S108. Dry etching inherits the microlens template layer into the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array.

[0046] like Figure 12 As shown, ICP dry etching was used with an upper electrode of 200W and a lower electrode of 35W. The etching atmosphere was 30 sccm of CF4 and 1 sccm of CH4, and the etching time was 600s. This resulted in a double-layer spin-coated glass microlens array 400, consisting of the first layer of spin-coated glass 411 and the second layer of spin-coated glass 412 after etching. Since the etching selectivity ratio of the spin-coated glass to the 5312 positive photoresist under these etching conditions was 1.8, the resulting microlenses exhibited a semi-ellipsoidal structure with a large aspect ratio. At the same time, the first layer of spin-coated glass 401 above the pad metal layer 203 was completely removed at the end of the etching process, exposing the Au layer and ensuring the yield of subsequent bonding wires. The remaining spin-coated glass 421 is the first layer of glass remaining on the surface of the annular metal layer 204.

[0047] It should be further noted that, as a specific example, the etching scheme and etching selectivity are not fixed. In this embodiment, a combination of CF4 and CH4 or Cl2 and BCl3 is selected. In some alternative embodiments, O2, CHF3, C4H8, SF6, etc. can also be selected to obtain different etching selectivity and conformity. The specific selection can be made according to the actual scheme.

[0048] Example 2 The second embodiment of the present invention provides a method for fabricating a microlens structure Micro-LED light-emitting module. The difference between the microlens structure Micro-LED light-emitting module in this embodiment and the microlens structure Micro-LED light-emitting module in the first embodiment lies in step S108, specifically: like Figure 14 As shown, ICP dry etching was used with an upper electrode of 330W and a lower electrode of 180W. The etching atmosphere was Cl2 at 40 sccm and BCl3 at 40 sccm, and the etching time was 600s. This resulted in a double-layer spin-coated glass microlens array 400, consisting of the first layer spin-coated glass 411 and the second layer spin-coated glass 412 after etching. Since the etching selectivity ratio of the spin-coated glass to the 5312 positive photoresist under these etching conditions is approximately 1, the resulting microlenses exhibit a hemispherical structure with a small aspect ratio. At the same time, the first layer spin-coated glass 401 above the pad metal layer 203 was completely removed at the end of the etching process, exposing the Au layer and ensuring the yield of subsequent bonding wires. The remaining spin-coated glass 421 is the first layer spin-coated glass that separates the double-layer spin-coated glass microlens array 400 from the N-type semiconductor layer 102.

[0049] Example 3 The third embodiment of the present invention provides a method for fabricating a microlens structure Micro-LED light-emitting module. The difference between the microlens structure Micro-LED light-emitting module in this embodiment and the microlens structure Micro-LED light-emitting module in the first embodiment lies in steps S104 and S108, wherein, in step S104: like Figure 15 As shown, SiN was first deposited from top to bottom on the surface of the driving substrate 200 using PECVD. x / SiO2, SiN x The SiNx / SiO2 layer with a thickness of 200 / 2000nm is filled in the spacing region 106 between the light-emitting semiconductor layer pixel array. Then, photolithography, development, and ICP etching are performed to remove the SiNx / SiO2 on the surface of the N-type semiconductor layer 102, the pad metal layer 203, and the ring metal layer 204 to obtain an insulating passivation layer 126.

[0050] Further, in step S108: like Figure 19 As shown, ICP dry etching was used with an upper electrode of 200W and a lower electrode of 35W. The etching atmosphere was 30 sccm of CF4 and 1 sccm of CH4, and the etching time was 600s. This resulted in a double-layer spin-coated glass microlens array 400, consisting of the first layer of spin-coated glass 411 and the second layer of spin-coated glass 412 after etching. Since the etching selectivity ratio of the spin-coated glass to the 5312 positive photoresist under these etching conditions was 1.8, the resulting microlenses exhibited a semi-ellipsoidal structure with a large aspect ratio. Moreover, due to the different front-end processes, the double-layer spin-coated glass microlens array 400 could completely cover the light-emitting semiconductor layer pixel array 120. At the same time, at the end of the etching, the first layer of spin-coated glass 401 above the pad metal layer 203 was also completely removed, exposing the Au layer and ensuring the yield of subsequent bonding wires. The remaining spin-coated glass 421 is the first layer of spin-coated glass that separates the double-layer spin-coated glass microlens array 400 from the N-type semiconductor layer 102.

[0051] Example 4 The fourth embodiment of the present invention provides a microlens structure Micro-LED light-emitting module, including a driving module and a light-emitting module. The light-emitting module includes a plurality of light-emitting semiconductor layer pixel units to form a light-emitting semiconductor layer pixel array. The driving module includes a driving substrate metal layer and is connected to the light-emitting semiconductor layer pixel array.

[0052] In this embodiment, the light-emitting module further includes multiple bonding metal layers 105 to form a bonding metal layer array 115. The bonding metal layer array 115 corresponds one-to-one with the light-emitting semiconductor layer pixel array 120 and connects the driving substrate metal layer 210 and the light-emitting semiconductor layer pixel array 120. Specifically, the driving substrate metal layer 210 includes a pad metal layer 203, an annular metal layer 204, and a positive electrode metal bump array 205. The pad metal layer 203, the annular metal layer 204, and the positive electrode metal bump array 205 are stacked sequentially and correspond one-to-one. The light-emitting semiconductor layer pixel array 120 and the positive electrode metal bump array 205 are respectively configured to correspond one-to-one.

[0053] Furthermore, the light-emitting module also includes a first spin-coated glass layer 401 and an N-type electrode layer 107. The first spin-coated glass layer 401 is disposed above the light-emitting semiconductor layer pixel unit, and the N-type electrode layer 107 is disposed between the first spin-coated glass layer 401 and the light-emitting semiconductor layer pixel unit and connects the light-emitting semiconductor layer pixel unit. The light-emitting module also includes a plurality of second spin-coated glass layers 402 to form a second spin-coated glass array. The second spin-coated glass layers 402 are disposed above the first spin-coated glass layers 401. Furthermore, the outer surface of the second spin-coated glass layers 402 is an arc-shaped curved surface to form a microlens structure. As a specific example, the outer surface of the second spin-coated glass layers is hemispherical or semi-ellipsoidal.

[0054] The light-emitting module also includes a passivation layer 126 and a full-surface passivation layer 116. The passivation layer 126 is disposed between the pad metal layer 203 and the annular metal layer 204. The full-surface passivation layer 116 is disposed between the driving module 200 and the first spin-coated glass layer 401 to fill the spacing region 106 between two adjacent light-emitting semiconductor layer pixel units and is flush with the upper surface of the light-emitting semiconductor layer pixel array 120 to form a flat surface. One end of the bonding metal layer 105 is disposed on the flat surface. The first spin-coated glass layer 401 is disposed above the passivation layer 126 and the full-surface passivation layer 116.

[0055] In summary, the microlens structure Micro-LED light-emitting module and its fabrication method in this embodiment, by adopting a double-layer spin-coated glass microlens structure, offers several advantages. Firstly, compared to simply depositing transparent materials, the process is simpler, which is beneficial for improving the uniformity of the product fabrication process and the product yield. Secondly, compared to pure spin-coating photoresist, the silicon dioxide-like material of the spin-coated glass has better stability, improving the bonding wire yield of the encapsulation. Furthermore, the first layer of spin-coated glass serves as the bottom layer for spin-coating the microlens material, spin-coating it onto the N-type electrode layer, passivation layer, and the entire passivation layer to process the composite and non-planar surface into a unified surface composed of only one material, achieving local planarization. This provides a unified surface for spin-coating the second layer of spin-coated glass, which is beneficial for the uniformity and repeatability of spin-coating the second layer of spin-coated glass, and helps improve the product yield for large-scale production. Secondly, a second layer of spin-coated glass is spin-coated onto the surface of the first layer of spin-coated glass. Photolithography is used to expose the pad area so that a dielectric layer film exists on the surface of the pad. This film is thinner than the dielectric layer in the pixel area. This allows the pads to be protected from over-etching at the beginning of the dry etching process. At the end of the dry etching process, the dielectric layer on the surface of the pad can be removed simultaneously. This eliminates the need to photolithographically etch and etch the pads again in subsequent steps for wire bonding, resulting in shorter process steps and more efficient production. Furthermore, this invention involves evaporating an easily oxidizable metal layer onto the surface of the N-type electrode layer. This oxidized metal then serves as the bonding layer between the metal and the spin-coated glass, transforming the original inert metal-spin-coated glass interface into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass. The layers are bonded together by stronger chemical bonds. This structure ensures that the spin-coated glass remains structurally stable during production and use, preventing cracking or peeling from the electrode and pad surfaces. Simultaneously, the process does not require additional photolithography steps.

[0056] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for fabricating a microlens structure Micro-LED light-emitting module, comprising obtaining a light-emitting semiconductor layer and a driving module, wherein the driving module includes a driving substrate metal layer, and the driving substrate metal layer includes a positive electrode metal bump array, characterized in that, The method further includes: A bonding metal layer is obtained, and the light-emitting semiconductor layer and the positive electrode metal bump array are bonded together through the bonding metal layer to bond and drive the module; the light-emitting semiconductor layer and the bonding metal layer are separated to obtain a light-emitting semiconductor layer pixel array and a bonding metal layer array that correspond one-to-one with the positive electrode metal bump array. A passivation layer is formed by filling the gap between the pixel array of the light-emitting semiconductor layer with spin-coated glass, polishing the passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer, etching the passivation layer to obtain the passivation layer, and evaporating a mesh-like N-type electrode layer in the N-type semiconductor layer. A first spin-coated glass layer, a second spin-coated glass layer, and a positive photoresist are sequentially spin-coated onto the N-type electrode layer, the passivation layer, and the entire passivation layer. After photolithography and development, a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array is obtained. A hot-melt reflow of positive photoresist dots is used to obtain a microlens template layer with a spherical cap morphology. Dry etching is then used to transfer the microlens template layer to the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array.

2. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, characterized in that, The steps of sequentially spin-coating a first layer of spin-coated glass, a second layer of spin-coated glass, and positive photoresist onto an N-type electrode layer, a passivation layer, and a full-surface passivation layer, followed by photolithography and development, to obtain a positive photoresist dot array that corresponds one-to-one with the positive electrode metal bump array include: A first layer of spin-coated glass is spin-coated onto the N-type electrode layer, the passivation layer, and the entire passivation layer, and then cured. Then, a second spin-coated glass layer is spin-coated on the first spin-coated glass layer, and photolithography is performed to expose the first spin-coated glass layer above the pad metal layer. The layer is then cured. The second spin-coated glass layer is a photosensitive spin-coated glass. Then, positive photoresist is spin-coated onto the surface of the second spin-coated glass layer. After photolithography and development of the positive photoresist, a positive photoresist dot array corresponding one-to-one with the positive electrode metal bump array is obtained. The step of spin-coating a first layer of spin-coated glass onto the N-type electrode layer, the passivation layer, and the entire passivation layer includes the following method for spin-coating the first layer of spin-coated glass onto the N-type electrode layer: A layer of easily oxidizable metal is evaporated on the surface of the N-type electrode layer to oxidize the surface and obtain an adhesive layer. The adhesive layer is used to bond the metal and spin-coated glass to transform the original inert metal-spin-coated glass interface on the surface of the N-type electrode layer into a multilayer structure of inert metal-active metal-metal oxide-spin-coated glass. The material of the N-type electrode layer is one or more combinations of Cr, Au, Pt, Ni, Al, and Ti; The top metal material of the N-type electrode layer is one or more combinations of Ti, Cr, Ni, and Al; the method of oxidizing the top metal of the N-type electrode layer is one or more combinations of static natural oxidation, ICP oxygen ion bombardment, and peroxide oxidation.

3. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, characterized in that, In the step of dry etching to inherit the microlens template layer to the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array: ICP dry etching was used with an upper electrode of 330W and a lower electrode of 180W. The etching atmosphere included Cl2 and BCl3, and the etching time was 600s. This yielded a double-layer spin-coated glass microlens array consisting of the first and second spin-coated glass layers after etching.

4. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 3, characterized in that, The etching selectivity ratios of the first and second spin-coated glass layers to the positive photoresist are 1, respectively.

5. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, characterized in that, In the step of dry etching to inherit the microlens template layer to the first and second spin-coated glass layers to obtain a double-layer spin-coated glass microlens array: ICP dry etching was used with an upper electrode of 200W and a lower electrode of 35W. The etching atmosphere included CF4 and CH4, and the etching time was 600s. This yielded a double-layer spin-coated glass microlens array consisting of a first layer of spin-coated glass and a second layer of spin-coated glass after etching.

6. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 5, characterized in that, The etching selectivity ratios of the first spin-coated glass layer to the positive photoresist and the second spin-coated glass layer to the positive photoresist both include 1.

8.

7. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, wherein the driving module further includes a driving substrate, and a metal layer of the driving substrate is disposed on the driving substrate, characterized in that, In the step of hot-melt reflow of positive photoresist dot array to obtain a microlens template layer with a spherical cap morphology: The driving substrate is placed on a baking tray and placed in a forced-air oven. It is heated to 165℃-175℃ and maintained for 5min-120min to allow the positive photoresist dot array to reach the glass transition temperature so that it becomes fluid. Under the action of surface tension, a microlens template layer with a spherical cap morphology is formed.

8. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, wherein the driving substrate metal layer further includes a pad metal layer and an annular metal layer, the pad metal layer, the annular metal layer, and the positive electrode metal bump array are stacked sequentially and correspond one-to-one, characterized in that: The steps of polishing the entire passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer, etching the entire passivation layer to obtain the passivation layer, and evaporating a mesh-like N-type electrode layer in the N-type semiconductor layer include: Polish the entire passivation layer to expose the N-type semiconductor layer in the light-emitting semiconductor layer; Etching removes the entire passivation layer on the surface of the pad metal layer and the annular metal layer to obtain the passivation layer; A mesh-like N-type electrode layer is evaporated in the N-type semiconductor layer, the ring metal layer, and the pad metal layer.

9. The method for fabricating a Micro-LED light-emitting module with a microlens structure according to claim 1, characterized in that, The steps of bonding the light-emitting semiconductor layer and the positive electrode metal bump array with a bonding metal layer to separate the light-emitting semiconductor layer and the bonding metal layer to obtain a light-emitting semiconductor layer pixel array and a bonding metal layer array that correspond one-to-one with the positive electrode metal bump array include: A bonding metal layer is deposited over the entire surface of the light-emitting semiconductor layer on a silicon substrate, and the bonding metal layer is bonded to the positive electrode metal bump array; The silicon substrate is removed to obtain the light-emitting semiconductor layer. The light-emitting semiconductor layer is then divided to form a light-emitting semiconductor layer pixel array. The light-emitting semiconductor layer pixel array corresponds one-to-one with the positive electrode metal bump array. The bonding metal layers are separated to form a bonding metal layer array that corresponds one-to-one with the positive electrode metal bump array.

10. A microlens structure Micro-LED light-emitting module, comprising a driving module and a light-emitting module, wherein the light-emitting module comprises a plurality of light-emitting semiconductor layer pixel units to form a light-emitting semiconductor layer pixel array, and the driving module comprises a driving substrate metal layer and is connected to the light-emitting semiconductor layer pixel array, characterized in that: The light-emitting module further includes multiple bonding metal layers to form a bonding metal layer array, wherein the bonding metal layer array corresponds one-to-one with the light-emitting semiconductor layer pixel array and connects the driving substrate metal layer and the light-emitting semiconductor layer pixel array; The light-emitting module further includes a first spin-coated glass layer, an N-type electrode layer, and a full-surface passivation layer. The first spin-coated glass layer is disposed above the light-emitting semiconductor layer pixel unit. The N-type electrode layer is disposed between the first spin-coated glass layer and the light-emitting semiconductor layer pixel unit and connects to the light-emitting semiconductor layer pixel unit. The light-emitting module further includes a plurality of second spin-coated glass layers to form a second spin-coated glass array. The second spin-coated glass layers are disposed above the first spin-coated glass layer. The passivation layer is disposed between the driving module and the first spin-coated glass layer to fill the gap between two adjacent light-emitting semiconductor layer pixel units and is flush with the upper surface of the light-emitting semiconductor layer pixel array to form a flat surface. One end of the bonding metal layer is disposed on the flat surface.

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