Coupling interface, laser chip-based optoelectronic co-packaged system and method of manufacturing the same

Abstract

This application relates to the semiconductor field, providing a coupling interface, a laser chip-based optoelectronic co-packaging system, and a method for fabricating the same. The coupling interface fabrication method includes providing a photosensitive resin composition doped with a metal precursor; coating the photosensitive resin composition doped with the metal precursor onto the surface of a laser chip; forming the coupling interface in a single, integrated process using a femtosecond laser; obtaining a polymer-metal precursor composite structure and processing it such that the reflective surface area of ​​the coupling interface is selectively converted into a continuous metal reflective film, while the emitting end face area of ​​the coupling interface retains an unmetallized or weakly metallized polymer surface; and depositing an antireflection film on the emitting end face. The coupling interface provided by this application enables in-situ, one-time integration of high-precision optical structures and high-reflectivity mirrors, with a simple and reliable process, and direct bonding with the laser chip, resulting in high coupling efficiency and good integration.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to coupling interfaces, laser chip-based optoelectronic co-packaging systems, and their fabrication methods. Background Technology

[0002] Vertical-cavity surface-emitting lasers (VCSELs) have become key light sources in high-speed optical interconnects, sensing, and consumer electronics due to their advantages such as low power consumption, miniaturization, and ease of two-dimensional integration. Efficiently coupling the light emitted by the laser chip into a planar optical waveguide (such as an optical waveguide in a glass substrate) is both fundamental and challenging for realizing high-performance optoelectronic integrated modules (such as co-packaged optical components (CPOs) and on-chip optical interconnects).

[0003] Traditional optical coupling schemes primarily rely on discrete optical components (such as microlenses, prisms, and mirrors) and precise mechanical alignment and assembly. For example, a common method involves placing a 45° micro-mirror in the laser chip's output path to deflect the vertically emitted light by 90° before coupling it into a horizontal waveguide via a separate lens. These schemes suffer from problems such as complex structure, large size, small alignment tolerance, and high assembly costs, making it difficult to meet the requirements of modern optoelectronic integration for high density, low cost, and high reliability. Summary of the Invention

[0004] The purpose of this application is to provide a coupling interface, a laser chip-based optoelectronic co-packaging system and its fabrication method. The coupling interface provided by this application can realize in-situ, one-time integration of high-precision optical structures (lenses) and high-reflectivity mirrors. The process is simple and reliable, and it can be directly bonded to the laser chip, with high coupling efficiency and good integration.

[0005] This application provides a method for preparing a coupling interface, comprising the following steps: S1. A photosensitive resin composition doped with a metal precursor is provided; S2. Clean and activate the surface of the laser chip's light output port, and coat its surface with the photosensitive resin composition doped with the metal precursor. S3. Using femtosecond laser-based two-photon polymerization 3D printing technology, the coupling interface is formed in one step and in one piece on the surface of the laser chip where the light outlet is located. The coupling interface includes a light-incident area, a reflective area and a light-guiding area arranged in sequence. The light-incident area can directly contact the laser chip, the reflective area has a reflective surface with a preset tilt angle, and the light-guiding area has an exit end face. S4. Remove the unpolymerized photosensitive resin composition doped with metal precursor to obtain a polymer-metal precursor composite structure. S5. The polymer-metal precursor composite structure is processed so that the area where the reflective surface is located is selectively transformed into a continuous metal reflective film, while the area where the emission end face is located retains an unmetallized or weakly metallized polymer surface. S6. Deposit an antireflection film on the exit end face.

[0006] In one embodiment, in step S1, the metal precursor includes at least one of metal nanoparticles and organometallic compounds; wherein the metal is aluminum, silver, or gold.

[0007] In one embodiment, the step of processing the polymer-metal precursor composite structure in step S5 is a heat treatment step, specifically including: heating the polymer-metal precursor composite structure to a preset temperature and holding it for a preset time in an inert gas or reducing atmosphere. When the metal precursor is gold nanoparticles or gold organometallic compound, the preset temperature is 240℃-280℃ and the preset time is 45-100 minutes. When the metal precursor is silver nanoparticles or gold organometallic compound, the preset temperature is 200°C to 260°C and the preset time is 25 minutes to 80 minutes. When the metal precursor is aluminum nanoparticles or gold organometallic compound, the preset temperature is 190°C to 250°C and the preset time is 30 minutes to 90 minutes.

[0008] In one embodiment, the metal precursor is aluminum nanoparticles with an organic ligand-modified surface, and the particle size is less than 100 nanometers, to ensure optical transparency and resolution during the two-photon polymerization 3D printing process.

[0009] In one embodiment, the step of processing the polymer-metal precursor composite structure in step S5 is a heat treatment step, specifically including: heating the polymer-metal precursor composite structure to a preset temperature and holding it for a preset time in an inert gas or reducing atmosphere, wherein the preset temperature is 160°C to 200°C and the preset time is 60 minutes to 90 minutes.

[0010] In one embodiment, the step S5 of processing the polymer-metal precursor composite structure is a laser selective irradiation step, specifically including: Using the same femtosecond laser system as the femtosecond laser-based two-photon polymerization 3D printing technology, the laser parameters were switched from polymerization mode to metallization mode: average power of 60mW-75mW, pulse repetition frequency of 100kHz, and scanning speed of 1mm / s. By precisely controlling the laser focus with a computer, only the reflective surface area inside the coupling interface is scanned with dense reciprocating scans at a spacing of 0.5 μm. The photothermal effect is used to sinter and fuse the aluminum nanoparticles in this area to form a continuous metallic aluminum reflective film; while the output end face of the coupling interface and other areas are not scanned.

[0011] In one embodiment, before step S5, the method further includes: performing a surface enrichment treatment on the reflective surface by plasma treatment or solvent vapor fumigation, so that the concentration of metal precursor on the surface of the reflective surface is higher than that inside the structure and on the exit end face, so as to promote selective metallization.

[0012] This application also provides a method for fabricating a coupling interface, which forms a coupling interface used to realize optical transmission between a laser chip and a waveguide. The coupling interface is used to transmit the laser emitted by the laser chip to the waveguide in a manner parallel to the waveguide; the coupling interface is an integrated coupling interface based on photosensitive resin; one coupling interface corresponds to one laser chip; The coupling interface includes, in sequence, an incident light area, a reflective area, and a light guiding area; The top of the light-incident area is in direct contact with the surface of the light-out port of the laser chip; The top diameter of the light-incident area is greater than or equal to the light-out port diameter of the laser chip; The reflection area has a reflective surface coated with a metal reflective film; the minimum angle between the reflective surface and the plane where the waveguide is located is the tilt angle of the reflection area, and the tilt angle is set to 10°-80°; The light guide area has an exit end face coated with an antireflective film.

[0013] In one embodiment, the cross-sectional shape of the incident light area is rectangular, circular, or gradually changes from the top towards the reflective area.

[0014] In one embodiment, the exit face of the light guide region is a parabolic or freeform surface used for beam shaping and focusing.

[0015] In one embodiment, the metal reflective film is an aluminum film, and the antireflective film is a non-conductive single-layer dielectric film, wherein the material of the single-layer dielectric film is silicon dioxide, magnesium fluoride, or aluminum oxide.

[0016] This application also provides a photoelectric co-packaging system based on a laser chip, comprising: a coupling interface formed by the coupling interface preparation method described in any of the above embodiments, which is integrated between the laser chip and the waveguide, wherein the coupling interface is used to transmit the laser emitted by the laser chip to the waveguide in a manner parallel to the waveguide; The optoelectronic co-packaging system based on the laser chip further includes: a lens disposed outside the light guide area of ​​the coupling interface; the lens focuses the laser emitted from the laser chip and transmitted through the coupling interface to reduce the divergence angle of the laser, so that the laser is aligned with the waveguide for transmission.

[0017] This application also provides a method for fabricating an optoelectronic co-packaging system based on a laser chip, including: S10, a glass substrate is provided, and at least one waveguide and at least one microgroove are fabricated on the glass substrate; the waveguide is a horizontal waveguide; the microgroove is used to accommodate the coupling interface described in any of the above embodiments; S20, a chip substrate on which a laser chip is formed is provided, and the coupling interface is formed using the coupling interface fabrication method described in any of the above embodiments; S30, the glass substrate with the microgrooves formed in S10 and the chip substrate with the coupling interface formed in S20 are aligned and mounted to form a laser chip-based optoelectronic co-packaging system including the laser chip, the waveguide, and the coupling interface.

[0018] This application has at least the following advantages or beneficial effects: 1. This application provides a novel, highly integrated method for fabricating a coupling interface between a laser chip and a waveguide. The core of this method lies in using a specialized photosensitive resin with a metal-doped precursor to integrally print a complete structure including both reflective and transmissive surfaces in a single step via two-photon polymerization. Then, through post-processing, a metal film is selectively formed only on the internal reflective surface. This method fundamentally avoids the problems of traditional solutions that rely on discrete optical components (such as microlenses, prisms, and mirrors) and precise mechanical alignment and assembly. It achieves in-situ, one-step integration of high-precision optical structures (lenses) and high-reflectivity mirrors. The process is simple and reliable, and it directly bonds to the laser chip, resulting in high coupling efficiency and good integration.

[0019] 2. This application specifies the possible types of metal precursors (nanoparticles, organic compounds), listing aluminum, silver, and gold as preferred metals. This embodiment provides a broad and feasible range of metal precursor materials; aluminum is advantageous for high reflectivity over a wide wavelength range, silver for extremely high reflectivity, and gold for stability and specific wavelength ranges. When fabricating specific coupling interfaces, different optical performance and cost requirements can be flexibly adapted.

[0020] 3. In this application embodiment, surface-modified aluminum nanoparticles are further preferred as the metal precursor. Their particle size of less than 100 nanometers ensures the optical transparency of the resin at the printing wavelength, without affecting the spatial resolution of two-photon polymerization. Since the aluminum nanoparticles are already in a metallic state, post-processing (such as low-temperature heat treatment or laser sintering) mainly removes ligands and promotes particle fusion, making it easier to form high-quality aluminum reflective surfaces at relatively low temperatures, thus avoiding damage to the polymer structure caused by high temperatures.

[0021] 4. This application protects the coupling interface product itself prepared by the aforementioned method. This product is an integrated, miniaturized optical element based on photosensitive resin. Its unique polymer matrix + built-in selective metal reflective film structure gives it the advantages of light weight, high integration with laser chips, and complete optical functions (integration of reflection and transmission). The design of one interface corresponding to one laser chip is very suitable for parallel coupling applications of laser chip arrays. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the method for preparing the coupling interface in an embodiment of this application; Figure 2 This is a schematic diagram of the application structure of a coupling interface in an embodiment of this application; Figure 3 This is a schematic diagram of the application structure of another coupling interface in the embodiments of this application; Figure 4 This is a structural diagram of the coupling interface in the embodiments of this application, and a schematic diagram of its light output; Figure 5 This is a schematic diagram of the integrated optoelectronic co-packaging system based on a laser chip, as described in this application embodiment. Figure 6 This describes the formation process of the waveguide structure in the embodiments of this application; Figure 7 This describes the integration process of the laser chip, coupling interface, and waveguide structure in the embodiments of this application.

[0024] icon: Optoelectronic co-packaging system 100 based on laser chip: Laser chip 10, chip substrate 11; Coupler interface 20, light incident area 21, reflection area 22, light guiding area 23; Waveguide 30, glass substrate 31, microgroove 32; Through hole 41a, electrical connection structure 41, encapsulation structure 42. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] Please refer to the appendix to this application. Figures 1-7 This application employs two-photon polymerization 3D printing technology to form an integrated coupling interface 20 between the laser chip 10 and the waveguide 30. The coupling interface 20 is used to transmit the vertical laser emitted from the laser chip 10 to the waveguide 30 in a manner parallel to the waveguide 30. The laser chip 10 can be a single laser chip or an array of laser chips. Each laser chip 10 corresponds to one coupling interface 20, or each emitted laser beam corresponds to one coupling interface 20. The laser chip 10 in this application can be a VCSEL chip, a DFB chip, an EML chip, a silicon photonics chip, or other chips, etc.

[0032] Please see Figure 1 This application provides a method for fabricating a coupling interface 20, comprising the following steps: S1. A photosensitive resin composition doped with a metal precursor is provided.

[0033] S2. The surface of the laser chip 10 with the light output port is cleaned and activated, and a photosensitive resin composition doped with a metal precursor is coated on its surface.

[0034] S3. Using a femtosecond laser-based two-photon polymerization 3D printing process, a coupling interface 20 is formed in a single, integrated process on the surface of the laser chip 10 where the light outlet is located. For example... Figure 2 , Figure 3 and Figure 4 As shown, the coupling interface 20 includes a light-incident area 21, a reflection area 22, and a light-guiding area 23 arranged sequentially. The light-incident area 21 can directly contact the laser chip, the reflection area 22 has a reflective surface with a preset tilt angle, and the light-guiding area 23 has an exit end face. Figure 2 and Figure 3 These are schematic diagrams of application structures that implement coupling in different directions through coupling interface 20. Figure 4 This is a schematic diagram of the actual structure of the coupling interface 20. Figure 4 The diagram also illustrates the light transmission process of the incoming and outgoing light, as well as the outgoing light spot.

[0035] S4. Remove the unpolymerized photosensitive resin composition doped with metal precursors to obtain a polymer-metal precursor composite structure.

[0036] S5. The polymer-metal precursor composite structure is processed so that the area where the reflective surface is located is selectively transformed into a continuous metal reflective film, while the area where the emission end face is located retains an unmetallized or weakly metallized polymer surface.

[0037] S6. Deposit an antireflection film on the exit end face.

[0038] This embodiment provides a novel, highly integrated method for fabricating the coupling interface 20 between a laser chip and a waveguide. The core of this method lies in using a specialized photosensitive resin with a metal-doped precursor to integrally print a complete structure including both reflective and transmissive surfaces in a single step via two-photon polymerization. Then, through post-processing, a metal film is selectively formed only on the internal reflective surface. This method fundamentally avoids the problems of relying on discrete optical components (such as microlenses, prisms, and mirrors) and precise mechanical alignment and assembly in traditional solutions. It achieves in-situ, one-step integration of a high-precision optical structure (lens) and a high-reflectivity mirror surface. The process is simple and reliable, and it directly bonds to the laser chip 10, resulting in high coupling efficiency and good integration.

[0039] In one embodiment, in step S1, the metal precursor includes at least one of metal nanoparticles and organometallic compounds. The metal is aluminum, silver, or gold.

[0040] In this embodiment, the available types of metal precursors (nanoparticles, organic compounds) are specified, with aluminum, silver, and gold listed as preferred metals. This embodiment provides a broad and feasible range of metal precursor materials to choose from; aluminum is advantageous for high reflectivity over a wide wavelength range, silver for extremely high reflectivity, and gold for stability and specific wavelength ranges. When fabricating the specific coupling interface 20, different optical performance and cost requirements can be flexibly adapted.

[0041] In one embodiment, the metal precursor is aluminum nanoparticles with an organic ligand-modified surface, and the particle size is less than 100 nanometers, to ensure optical transparency and resolution during the two-photon polymerization 3D printing process.

[0042] In this embodiment, surface-modified aluminum nanoparticles are further preferred as the metal precursor. Their particle size of less than 100 nanometers ensures the optical transparency of the resin at the printing wavelength, without affecting the spatial resolution of two-photon polymerization. Since the aluminum nanoparticles are already in a metallic state, post-processing (such as low-temperature heat treatment or laser sintering) mainly removes ligands and promotes particle fusion, making it easier to form high-quality aluminum reflective surfaces at relatively low temperatures and avoiding damage to the polymer structure caused by high temperatures.

[0043] In one embodiment, the photosensitive resin composition doped with a metal precursor comprises, by weight percentage: 50% to 85% photopolymerizable monomers and oligomers, 10% to 40% metal precursor, 1% to 10% dispersant and stabilizer, and 0.1% to 5% rheology modifier and auxiliaries. Specifically, the photopolymerizable monomers and oligomers include acrylate monomers containing carboxyl, amino, or thiol functional groups. The dispersant and stabilizer include silane coupling agents or polymeric block copolymers having anchoring groups and solvating segments. The rheology modifier and auxiliaries include surface-treated fumed silica.

[0044] In one embodiment, the step of processing the polymer-metal precursor composite structure in step S5 is a heat treatment step, specifically including: heating the polymer-metal precursor composite structure to a preset temperature and holding it for a preset time in an inert gas or reducing atmosphere.

[0045] When setting the preset temperature, it must meet the following conditions: sufficient to decompose or reduce the metal precursor enriched in the reflective surface area to form a metal mirror, while being lower than the temperature at which the polymer structure undergoes significant deformation or degradation. In one embodiment, when the metal precursor is gold nanoparticles or an organogold compound, the preset temperature is 240℃-280℃, and the preset time is 45-100 minutes. In one embodiment, when the metal precursor is silver nanoparticles or an organogold compound, the preset temperature is 200°C to 260°C and the preset time is 25 minutes to 80 minutes. In one embodiment, when the metal precursor is aluminum nanoparticles or an organometallic gold compound, the preset temperature is 190°C to 250°C, and the preset time is 30 minutes to 90 minutes.

[0046] In one embodiment, when the metal precursor is aluminum nanoparticles with surface-modified organic ligands and a particle size of 80 nm, the preset temperature is 160°C to 200°C and the preset time is 60 minutes to 90 minutes.

[0047] This embodiment provides a specific and mature selective metallization route using heat treatment. An optimized process window with preset temperature and time under a protective atmosphere is defined. These conditions are sufficient to effectively decompose or reduce the metal precursor in the reflective surface region into a continuous metal film, while ensuring that the polymer matrix does not undergo significant deformation or degradation. The process offers good controllability and is suitable for batch processing. Specific Implementation

[0048] S1 comprises a photosensitive resin composition doped with a metal precursor, which, by mass percentage, includes: 55% acrylate monomers containing carboxyl groups, 80 nm aluminum nanoparticles, 6% silane coupling agent, and 4% surface-treated fumed silica. S2-S4 follow the steps described in the above embodiments.

[0049] In step S5, the printed polymer-metal precursor composite structure is placed in a tube furnace and an argon-hydrogen mixture (Ar:H2 = 95:5) is introduced. The temperature is increased to 240°C at a rate of 5°C / min, held for 30 minutes, and then allowed to cool naturally. Under these conditions, a continuous aluminum film forms on the reflective surface, exhibiting a reflectivity of over 85% for 850nm laser light, and no visible deformation is observed in the coupling interface 20 structure. Step S6 further deposits an antireflection film on the exit end face. Specific Implementation

[0050] S1 comprises a photosensitive resin composition doped with a metal precursor, which, by mass percentage, includes: 60% acrylate monomers containing carboxyl groups, 30% aluminum nanoparticles with a particle size of 80 nm and surface-modified with organic ligands, 6% silane coupling agent, and 4% surface-treated fumed silica. S2-S4 follow the steps described in the above embodiments.

[0051] In step S5, the printed polymer-metal precursor composite structure is placed in a tube furnace and an argon-hydrogen mixture (Ar:H2 = 95:5) is introduced. The temperature is increased to 180°C at a rate of 5°C / min, held for 60 minutes, and then allowed to cool naturally. Since the nanoparticles are already in a metallic state, the heat treatment primarily aims to remove surface ligands and promote particle sintering and fusion. Therefore, a continuous aluminum film can be formed on the reflective surface after treatment at temperatures below 200°C for 60 minutes. This temperature (below 200°C) is far below the temperature at which the substrate softens significantly. No visible deformation is observed in the coupling interface 20 structure. Step S6 further deposits an antireflective film on the exit face.

[0052] Figure 4 The gray coupling interface 20 on the left is a schematic diagram of the actual structure of the coupling interface 20 prepared by the method in the above-described specific embodiment 1 of this application. Figure 4 The blue light inside the coupling interface 20 is a schematic diagram of the transmission process of the incoming and outgoing light rays. Figure 4 The emitted light beam hitting the gray background is illustrated in the enlarged image in the upper right corner. Figure 4 It can be seen that the emitted light spot has a regular shape, clear edges, and concentrated energy, indicating that the light guide area 23 of the coupling interface 20 has a good shaping and focusing effect on the light beam.

[0053] In one embodiment, the step S5 of processing the polymer-metal precursor composite structure is a laser selective irradiation step, specifically including: Using the same femtosecond laser system (center wavelength 780nm, pulse width 100fs) as the femtosecond laser-based two-photon polymerization 3D printing technology, the laser parameters were switched from polymerization mode to metallization mode: average power of 60mW-75mW, pulse repetition frequency of 100kHz, and scanning speed of 1mm / s.

[0054] By precisely controlling the laser focus using a computer, only the reflective surface region inside the coupling interface is scanned with dense reciprocating scans at intervals of 0.5 μm. The photothermal effect causes the aluminum nanoparticles in this region to sinter and fuse, forming a continuous metallic aluminum reflective film (reflectivity >90%). The exit face and other areas of the coupling interface are not scanned. The aluminum nanoparticles on the exit face and other areas of the coupling interface remain uniformly dispersed in the polymer matrix, maintaining light transmission. Subsequently, an antireflective film is deposited on the exit face or a transmission mirror is installed to complete the fabrication of the coupling interface.

[0055] This embodiment provides a highly spatially selective, non-contact alternative metallization path—laser selective irradiation—achieving in-situ selective metallization of reflective and transmissive surfaces within the same structure. This avoids the thermal stress problems associated with overall heat treatment, offering a flexible and highly precise process. By precisely controlling the laser beam to scan only the reflective surface, local conversion is achieved using photothermal or photochemical effects, completely avoiding the overall thermal stress problems that may arise from heat treatment methods. This approach is particularly suitable for heat-sensitive structures or applications requiring precise local control, offering exceptional flexibility.

[0056] In one embodiment, in the polymerization printing mode, the femtosecond laser parameters are set as follows: average power of 110% to 130% of the polymerization threshold, pulse repetition frequency of 80 MHz, vector scanning based on 3D model slices, and scanning speed of 10 mm / s to 1000 mm / s. The polymerization threshold is the lowest average laser power density (or critical power density) capable of initiating a two-photon polymerization reaction and causing the photosensitive resin to crosslink and cure. The polymerization threshold varies depending on the formulation of the photosensitive resin.

[0057] For the photosensitive resin composition doped with a metal precursor described in Specific Example 1, the polymerization threshold is determined by using a femtosecond laser system with a center wavelength of 780 nm and a pulse width of 100 fs. The average laser power corresponding to this polymerization threshold is typically in the range of 10 mW to 50 mW (this value corresponds to the power at the focal point). Therefore, in the polymerization printing mode, the average power of the femtosecond laser is set between 11 mW and 65 mW to ensure stable polymerization while avoiding damage to the material.

[0058] For the photosensitive resin composition doped with a metal precursor described in Specific Example 2, a femtosecond laser system with a center wavelength of 780 nm and a pulse width of 100 fs is also used. The average laser power corresponding to the polymerization threshold is typically in the range of 12 mW to 60 mW (this value corresponds to the power at the focal point). Therefore, in the polymerization printing mode, the average power of the femtosecond laser is set between 13.2 mW and 78 mW to ensure stable polymerization while avoiding damage to the material. Therefore, in the polymerization printing mode, the average power of the femtosecond laser can be set in the range of 10 mW to 80 mW.

[0059] After switching to the metallization mode, the femtosecond laser parameters are adjusted as follows: the average power is greater than the average power in the polymer printing mode, the pulse repetition frequency is adjusted to 1kHz-200kHz, and a uniform surface scan is performed on the reflective surface area at a scanning speed of 0.1mm / s-10mm / s.

[0060] In one embodiment, the scanning strategy of the metallization processing mode is to make the laser focus perform multiple reciprocating scans in the reflective surface area, and the spacing between adjacent scanning paths is equal to or slightly smaller than the diameter of the laser focus.

[0061] In one embodiment, during the metallization process, the laser power or the number of scans is controlled in real time by monitoring changes in the online optical reflectivity or scattered light intensity of the reflective surface region until a signal indicates that a continuous metal film has been formed.

[0062] In one embodiment, before step S5, the method further includes: performing a surface enrichment treatment on the reflective surface, which involves plasma treatment or solvent vapor fumigation to make the concentration of metal precursors on the surface of the reflective surface higher than that inside the structure and at the exit end face, so as to promote selective metallization.

[0063] In this embodiment, adding a surface enrichment step (plasma treatment or solvent fumigation) before metallization can actively increase the concentration of metal precursors on the reflective surface. This is like laying a more easily ignited fuse for the selective metallization reaction, significantly promoting the selective and uniform formation of the metal film in the target area, improving the success rate and repeatability of the process, and ensuring the high quality of the final reflective mirror.

[0064] Please see Figure 2 and Figure 3This application also provides a coupling interface 20 formed using the coupling interface fabrication method described in any of the above embodiments. The coupling interface 20 is an integrated laser chip-waveguide coupling interface structure. The coupling interface 20 is used to realize optical transmission between the laser chip 10 and the waveguide 30. In one embodiment, the coupling interface 20 is used to transmit the laser emitted by the laser chip 10 to the waveguide 30 in a manner parallel to the waveguide 30. The coupling interface 20 is an integrated coupling interface 20 based on photosensitive resin. The coupling interface 20 includes: a light-incident area 21, a reflection area 22, and a light-guiding area 23 arranged sequentially. The top end of the light-incident area 21 is in direct contact with the surface where the light-emitting port of the laser chip 10 is located. One coupling interface 20 corresponds to one laser chip 10. The diameter of the top end of the light-incident area 21 is greater than or equal to the diameter of the light-emitting port of the laser chip 10. The light-incident area 21 can be set as a cube (cube, cuboid), cylinder, cone, or other shapes.

[0065] The reflecting region 22 has a reflective surface coated with a metal reflective film. The minimum angle between the reflective surface and the plane containing the waveguide 30 is the tilt angle of the reflecting region 22, which is set between 10° and 80°. The specific tilt angle can be set to any angle between 10° and 80°, with a preferred tilt angle of 45° for easier focusing. Setting the tilt angle of the reflecting region 22 to 45° allows the vertical laser emitted by the laser chip 10 to be converted into a horizontal laser that can enter the horizontally placed waveguide 30.

[0066] The light guide region 23 has an exit face coated with an antireflection film. The light guide region 23 is positioned corresponding to the core layer (the layer with the highest refractive index) of the waveguide 30 (light emitted from the light guide region 23 is transmitted to the core layer of the waveguide 30. The center of the light guide region 23 and the center of the core layer of the waveguide 30 are on the same straight line). That is, the light guided by the light guide region 23 of the integrated laser chip-waveguide coupling interface structure converges to the core layer of the waveguide 30 of the optical waveguide. The integrated laser chip-waveguide coupling interface structure is an integrated structure of a mirror and a lens. The integrated laser chip-waveguide coupling interface structure is formed using two-photon polymerization (TPP) technology. TPP is a high-precision micro / nano 3D printing technology based on the interaction between a femtosecond laser and photosensitive resin.

[0067] An integrated laser chip-waveguide coupling interface structure is mounted on the surface of the laser chip 10's light-emitting port, enabling light transmission between the optical waveguide 30 in the glass substrate 31 and the laser chip 10. The laser chip 10 emits light, which is refracted by the integrated laser chip-waveguide coupling interface structure and transmitted to the optical waveguide 30. The body of the integrated laser chip-waveguide coupling interface structure is photosensitive resin. The integrated laser chip-waveguide coupling interface structure has a light-incident area 21, a reflection area 22, and a light-guiding area 23 arranged sequentially. The top of the light-incident area 21 is in direct contact with the surface of the laser chip 10's light-emitting port. The diameter of the top of the light-incident area 21 is greater than or equal to the diameter of the laser chip 10's light-emitting port. The light-guiding area 23 is correspondingly positioned to the waveguide 30 core layer (the film layer with the highest refractive index) of the optical waveguide 30 (light emitted from the light-guiding area 23 is transmitted to the waveguide 30 core layer of the optical waveguide 30. The center of the light-guiding area 23 and the center of the waveguide 30 core layer are on the same straight line). That is, the light guided by the light-guiding area 23 of the integrated laser chip-waveguide coupling interface structure is converged to the core layer of the waveguide 30. The integrated laser chip-waveguide coupling interface structure is an integrated structure of a mirror and a lens. The integrated laser chip-waveguide coupling interface structure is formed using two-photon polymerization technology. Two-photon polymerization (TPP) is a high-precision micro-nano 3D printing technology based on the interaction between a femtosecond laser and photosensitive resin.

[0068] In this embodiment, the coupling interface product itself, prepared by the aforementioned method, is protected. This product is an integrated, miniaturized optical element based on photosensitive resin. Its unique polymer matrix and built-in selective metal reflective film structure give it the advantages of light weight, high integration with laser chips, and complete optical functions (integration of reflection and transmission). The design of one interface corresponding to one laser chip is ideal for parallel coupling applications of laser chip arrays.

[0069] In one embodiment, the cross-sectional shape of the incident light area 21 is rectangular, circular, or gradually changes from the top towards the reflective area 22.

[0070] In this embodiment, the specific shape (rectangular, circular, or gradient) of the cross-section of the light-receiving region 21 is defined. Different shapes can better match laser chips with different emission modes (such as single-mode and multi-mode), optimize light reception efficiency, reduce interface reflection loss, and improve overall coupling efficiency.

[0071] In one embodiment, the exit end face of the light guide region 23 is a parabolic or freeform surface used for beam shaping and focusing.

[0072] In this embodiment, the exit surface of the light guide region is specified as a parabolic or freeform surface. This aspherical design can efficiently shape and converge the light beam, compensate for aberrations, and couple the light spot more precisely into the waveguide core layer, thereby maximizing coupling efficiency. This is a key optical design for achieving high-performance coupling.

[0073] In one embodiment, the metal reflective film is an aluminum film, and the antireflective film is a non-conductive single-layer dielectric film, the material of which is silicon dioxide, magnesium fluoride, or aluminum oxide.

[0074] In this embodiment, the metal film is specifically defined as a highly reflective aluminum film, and the antireflection film is a non-conductive single-layer dielectric film (such as SiO2, MgF2, Al2O3). The aluminum film ensures a wide wavelength range and high reflectivity from ultraviolet to infrared; the non-conductive antireflection film avoids the introduction of additional electrical interference and minimizes Fresnel reflection loss at the exit surface, allowing more light energy to enter the waveguide.

[0075] Please see Figure 5 This application also provides an integrated optoelectronic co-packaging system 100 based on a laser chip. A two-photon polymerization 3D printing technology is used to form an integrated coupling interface 20 between the laser chip 10 and the waveguide 30 (which is a horizontal waveguide). The coupling interface 20 is used to transmit the laser emitted by the laser chip 10 to the waveguide 30 in a manner parallel to the waveguide 30.

[0076] Figure 5 The illustrated optoelectronic co-packaging system 100 based on laser chips includes two laser chips 10, two horizontal waveguides 30, and two integrated coupling interfaces 20. The two laser chips 10 are spaced apart on a chip substrate 11. The two parallel waveguides 30 are spaced apart on a glass substrate 31. Two microgrooves 32 are formed in the glass substrate 31. The two microgrooves 32 have different depths. The spacing between the two microgrooves 32, and the specific dimensions of each microgroove 32, must be matched to the spacing of the two laser chips 10 and the specific dimensions of the coupling interfaces 20. An electrical connection structure 41 is also provided in the glass substrate 31 for electrically connecting the two laser chips 10 to external devices. The optoelectronic co-packaging system 100 based on laser chips also includes a packaging structure 42 disposed on the glass substrate 31 away from the laser chips. In one embodiment, a positioning structure is also formed on the bottom surface of the chip substrate 11 for alignment and mounting with the microgrooves 32 on the glass substrate 31.

[0077] In this embodiment, the laser chip-based optoelectronic co-packaging system 100, which includes the integrated coupling interface, is protected at the system level. Due to the aforementioned innovative interface structure and fabrication method, the laser chip-based optoelectronic co-packaging system 100 has significant advantages, including ultra-small size, large coupling alignment tolerance, simple fabrication process, and suitability for mass production. It provides a core solution for realizing high-density, low-cost, and high-performance optoelectronic integrated modules (such as CPOs).

[0078] In one embodiment, the optoelectronic co-packaging system 100 based on a laser chip further includes a lens disposed outside the light guide area of ​​the coupling interface; the lens focuses the laser emitted from the laser chip 10 and transmitted through the coupling interface 20 to reduce the laser divergence angle, thereby aligning the laser with the waveguide 30 for transmission. In this embodiment, the addition of an outer lens goes beyond a simple focusing concept. It represents a system-level performance enhancement and engineering robustness assurance strategy. It not only directly enhances system performance by improving coupling efficiency but also significantly improves manufacturing yield and long-term reliability by relaxing alignment tolerances and compensating for process errors. Furthermore, it provides greater flexibility in optical design to address more complex application scenarios.

[0079] Please see Figure 6 and Figure 7 This application also provides a method for fabricating an optoelectronic co-packaging system based on a laser chip, comprising: S10, a glass substrate 31 is provided, and at least one waveguide 30 is fabricated, the waveguide 30 being a horizontal waveguide; the glass substrate 31 has at least one microgroove 32 for accommodating the coupling interface 20; like Figure 6 As shown, the fabrication process of the horizontal waveguide 30 includes: A glass substrate 31 is provided.

[0080] Laser direct writing is performed on glass substrate 31 to form at least one waveguide 30. Figure 6 The laser only has two parallel horizontal waveguides (30).

[0081] A wet etching process is used to form a through-hole 41a (the through-hole is a TGV glass through-hole).

[0082] The surface of the glass substrate 31 is patterned and the through-holes 41a are plated with copper to form an electrical connection structure 41.

[0083] An encapsulation structure 42 is fabricated on the bottom surface of the glass substrate 31 (this step includes fabricating a protective layer / encapsulation structure layer and surface nickel plating).

[0084] Microgrooves 32 are fabricated on the top surface of the glass substrate 31. The microgrooves 32 are used to accommodate the integrated laser chip-waveguide coupling interface structure. The number of microgrooves 32 is the same as the number of optical waveguides 30.

[0085] S20, a chip substrate 11 on which the laser chip 10 is formed is provided, and the coupling interface 20 is formed using the method for preparing the coupling interface in any of the above embodiments, or using the coupling interface 20 described in any of the above embodiments. Figure 7 The chip substrate 11 shown includes two laser chips 10.

[0086] In step S30, the glass substrate 31 with microgrooves 32 formed in step S10 and the chip substrate 11 with coupling interface 20 formed in step S20 are aligned and mounted to form a laser chip-based optoelectronic co-packaging system 100 including laser chip 10, optical waveguide 30 and coupling interface 20.

[0087] This embodiment provides a complete and highly integrated method for fabricating a laser chip-based optoelectronic co-packaging system 100. The core of this method is to integrate the aforementioned integrally formed coupling interface 20 with a built-in high-reflectivity mirror into a three-dimensional heterogeneous structure with a glass substrate that has both optical waveguide and electrical interconnect functions and a laser chip through a clever microgroove alignment architecture.

[0088] This embodiment successfully integrates three distinct materials and functional components—a laser chip light source based on III-V semiconductors, a customized micro-optical coupling interface based on polymer materials, and a glass-based planar optical waveguide and electrical interconnect adapter board—in a compact vertical direction. This three-dimensional stacked architecture significantly saves lateral area, achieving ultra-high-density system-level integration and providing an ideal solution for space-sensitive applications such as consumer electronics and high-speed data center optical interconnects.

[0089] This microgroove serves as a precise mechanical positioning reference, enabling the laser chip with a coupling interface to be accurately placed above the input end of the optical waveguide through passive alignment. This ingeniously transforms the difficult optical calibration problem into a relatively easy mechanical assembly problem, significantly reducing the alignment accuracy requirements and packaging complexity. Simultaneously, the TGV vias and surface circuits on the glass substrate achieve vertical electrical interconnection, naturally integrating with the horizontal optical interconnection (waveguide), forming an advanced packaging form that enables coordinated transmission of optical and electrical signals and highly efficient and reliable interlayer interconnection.

[0090] This embodiment not only demonstrates a method for constructing a high-performance optoelectronic co-packaging system based on a laser chip, but also provides an advanced packaging paradigm that efficiently integrates optical, electronic, and mechanical functions in three-dimensional space. It comprehensively addresses key challenges such as high-performance coupling, high-precision alignment, high-density integration, and mass production capability, possessing significant industrial application value.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for fabricating a coupling interface, characterized in that, Includes the following steps: S1. A photosensitive resin composition doped with a metal precursor is provided; S2. Clean and activate the surface of the laser chip's light output port, and coat its surface with the photosensitive resin composition doped with the metal precursor. S3. Using femtosecond laser-based two-photon polymerization 3D printing technology, the coupling interface is formed in one step and in one piece on the surface of the laser chip where the light outlet is located. The coupling interface includes a light-incident area, a reflective area and a light-guiding area arranged in sequence. The light-incident area can directly contact the laser chip, the reflective area has a reflective surface with a preset tilt angle, and the light-guiding area has an exit end face. S4. Remove the unpolymerized photosensitive resin composition doped with metal precursor to obtain a polymer-metal precursor composite structure. S5. The polymer-metal precursor composite structure is processed so that the area where the reflective surface is located is selectively transformed into a continuous metal reflective film, while the area where the emission end face is located retains an unmetallized or weakly metallized polymer surface. S6. Deposit an antireflection film on the exit end face.

2. The method for preparing the coupling interface according to claim 1, characterized in that, In step S1, the metal precursor includes at least one of metal nanoparticles and organometallic compounds; wherein the metal is aluminum, silver or gold.

3. The method for preparing the coupling interface according to claim 2, characterized in that, The step of processing the polymer-metal precursor composite structure in step S5 is a heat treatment step, which specifically includes: heating the polymer-metal precursor composite structure to a preset temperature and holding it for a preset time in an inert gas or reducing atmosphere. When the metal precursor is gold nanoparticles or gold organometallic compound, the preset temperature is 240℃-280℃ and the preset time is 45-100 minutes. When the metal precursor is silver nanoparticles or gold organometallic compound, the preset temperature is 200°C to 260°C and the preset time is 25 minutes to 80 minutes. When the metal precursor is aluminum nanoparticles or gold organometallic compound, the preset temperature is 190°C to 250°C and the preset time is 30 minutes to 90 minutes.

4. The method for preparing the coupling interface according to claim 1, characterized in that, The metal precursor is aluminum nanoparticles with organic ligands modified on the surface, and its particle size is less than 100 nanometers, to ensure optical transparency and resolution during the two-photon polymerization 3D printing process.

5. The method for preparing the coupling interface according to claim 4, characterized in that, The step of processing the polymer-metal precursor composite structure in step S5 is a heat treatment step, which specifically includes: heating the polymer-metal precursor composite structure to a preset temperature and holding it for a preset time in an inert gas or reducing atmosphere, wherein the preset temperature is 160°C to 200°C and the preset time is 60 minutes to 90 minutes.

6. The method for preparing the coupling interface according to claim 1, characterized in that, Step S5, which involves processing the polymer-metal precursor composite structure, is a laser selective irradiation step, specifically including: Using the same femtosecond laser system as the femtosecond laser-based two-photon polymerization 3D printing technology, the laser parameters were switched from polymerization mode to metallization mode: average power of 60mW-75mW, pulse repetition frequency of 100kHz, and scanning speed of 1mm / s. By precisely controlling the laser focus with a computer, only the reflective surface area inside the coupling interface is scanned with dense reciprocating scans at a spacing of 0.5 μm. The photothermal effect is used to sinter and fuse the aluminum nanoparticles in this area to form a continuous metallic aluminum reflective film; while the output end face of the coupling interface and other areas are not scanned.

7. The method for preparing the coupling interface according to claim 1, characterized in that, Before step S5, the method further includes: performing a surface enrichment treatment on the reflective surface, which involves plasma treatment or solvent vapor fumigation to make the concentration of metal precursors on the surface of the reflective surface higher than that inside the structure and on the exit end face, so as to promote selective metallization.

8. A coupling interface formed using the method for fabricating a coupling interface according to any one of claims 1 to 7, the coupling interface being used to realize optical transmission between a laser chip and a waveguide, characterized in that, The coupling interface is used to transmit the laser emitted by the laser chip to the waveguide in a manner parallel to the waveguide; The coupling interface is an integrated coupling interface based on photosensitive resin; One of the coupling interfaces corresponds to one of the laser chips; The coupling interface includes, in sequence, an incident light area, a reflective area, and a light guiding area; The top of the light-incident area is in direct contact with the surface of the light-out port of the laser chip; The top diameter of the light-incident area is greater than or equal to the light-out port diameter of the laser chip; The reflective area has a reflective surface coated with a metal reflective film; The minimum angle between the reflecting surface and the plane where the waveguide is located is the tilt angle of the reflecting area, and the tilt angle is set to 10°-80°. The light guide area has an exit end face coated with an antireflective film.

9. The coupling interface according to claim 8, characterized in that, The cross-sectional shape of the incident light area is rectangular, circular, or gradually changes from the top towards the reflective area.

10. The coupling interface according to claim 8, characterized in that, The exit face of the light guide area is a parabolic or freeform surface used for beam shaping and focusing.

11. The coupling interface according to claim 8, characterized in that, The metal reflective film is an aluminum film, and the antireflective film is a non-conductive single-layer dielectric film. The material of the single-layer dielectric film is silicon dioxide, magnesium fluoride, or aluminum oxide.

12. A photoelectric co-packaging system based on a laser chip, characterized in that, include: The coupling interface formed by the method of any one of claims 1 to 7 is integrated between the laser chip and the waveguide, and the coupling interface is used to transmit the laser emitted by the laser chip to the waveguide in a manner parallel to the waveguide; The optoelectronic co-packaging system based on the laser chip further includes: a lens disposed outside the light guide area of ​​the coupling interface; the lens focuses the laser emitted from the laser chip and transmitted through the coupling interface to reduce the divergence angle of the laser, so that the laser is aligned with the waveguide for transmission.

13. A method for fabricating an optoelectronic co-packaging system based on a laser chip, characterized in that, include: S10, providing a glass substrate, and fabricating at least one waveguide and at least one microgroove on the glass substrate; The waveguide is a horizontal waveguide; the microgroove is used to accommodate the coupling interface as described in any one of claims 8-11; S20, a chip substrate on which a laser chip is formed is provided, and the coupling interface is formed using the method for preparing the coupling interface according to any one of claims 1-7; S30, the glass substrate with the microgrooves formed in S10 and the chip substrate with the coupling interface formed in S20 are aligned and mounted to form a laser chip-based optoelectronic co-packaging system including the laser chip, the waveguide, and the coupling interface.

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