Light engine with high airtightness

Abstract

The high-air-tightness light engine comprises a substrate, a support ring is arranged on the substrate, the middle part of the support ring is hollow, the hollow middle part of the support ring is used as a chip module setting area, and a chip module is arranged in the chip module setting area; a lens upper cover is arranged above the support ring; the support ring is used as a sealing element between the substrate and the lens upper cover; through the sealing effect of the support ring, the chip module setting area forms a high-air-tightness sealing area, the chip module setting is performed in the high-air-tightness sealing area, a three-layer stacking structure of "bottom plate-support ring-lens upper cover" is formed, the air-tight cavity packaging of the optoelectronic chip is realized by using a metal eutectic welding process between the support ring, the substrate and the lens upper cover, a high-reliability, high-performance and wafer-level batch-manufacturable light engine sealing structure is formed; an annular metallization layer is prepared on the outer edge area of the upper surface of the substrate through thin film deposition; and a bonding interface in the bottom layer of the three-layer air-tight structure of "bottom plate-support ring-upper cover" is formed.

Description

Technical Field

[0001] This invention relates to optoelectronic communication technology and its equipment, specifically, a highly airtight optical engine. Background Technology

[0002] With the rapid development of data centers and high-speed communication networks, the requirements for the performance and reliability of optical engines are increasing.

[0003] Traditional optical engine packaging technology mainly suffers from the following technical problems: Insufficient hermeticity: Optical engine packaging typically uses non-hermetic packaging with polymer adhesives, such as COB packaging. Although the cost is low, it has problems such as high moisture permeability, release of organic gases, and poor long-term thermal aging performance. It is easily corroded by moisture and harmful gases, affecting device performance, lifespan, and optical performance stability. This poses a challenge, especially for telecommunications-grade applications and harsh environment applications that require long lifespan.

[0004] Poor heat dissipation performance: The heat dissipation path of the electrical and optical chips is not smooth, which can easily cause heat accumulation when operating at high power, affecting the stability of the device.

[0005] The optical coupling efficiency is low, the optical coupling distance between the optical fiber and the optical chip is large, and there is a lack of precise optical alignment mechanism, resulting in high optical coupling loss.

[0006] Complex metal hermetically sealed packaging: This involves the use of Kovar alloy shells, parallel seam welding, etc., resulting in high costs. Integrating optical components is difficult and makes wafer-level mass production challenging.

[0007] Therefore, it is necessary to provide a highly airtight light engine to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a highly airtight optical engine. By using a modular, layered, and all-solid-state airtight packaging structure, it solves the problem of difficulty in balancing airtightness, high-density integration, long-term reliability, and manufacturing cost in the prior art. Through a three-layer stacked structure of "base plate-support ring-lens cover" and the use of metal eutectic bonding process to achieve airtight cavity packaging of optoelectronic chips, a highly reliable, high-performance optical engine solution suitable for wafer-level mass production is achieved.

[0009] The technical solution is as follows: A high-airtightness optical engine includes a substrate with a support ring on the substrate. The support ring has a hollow center, and the middle part of the hollow center serves as a chip module setting area, within which a chip module is set. A lens cover is positioned above the support ring. The support ring acts as a seal between the substrate and the lens cover. Through the sealing effect of the support ring, the chip module setting area forms a high-airtightness sealed region. Chip modules are set within this high-airtightness sealed region, forming a three-layer stacked structure of "base plate-support ring-lens cover". The support ring, substrate, and lens cover are sealed using a metal eutectic bonding process to achieve airtight cavity encapsulation of the optoelectronic chip, forming a highly reliable, high-performance optical engine sealing structure suitable for wafer-level mass production. On the outer edge of the substrate's upper surface, a continuous, closed annular metallization layer is prepared by thin film deposition, including sputtering Ti / Pt / Au or Cr / Cu / Au and patterning processes. The annular metallization layer, also known as the sealing ring, forms the bonding interface at the bottom layer of the three-layer hermetic structure of "base plate-support ring-top cover" through subsequent eutectic bonding. The annular metallization layer ensures that the solder is fully wetted and forms a pore-free, high-strength, hermetic weld through its uniformity, roughness, and metallurgical compatibility.

[0010] Furthermore, the chip module includes at least a set of optical chips and electrical chips.

[0011] Furthermore, an RDL layer is provided on the substrate, and advanced semiconductor thin film methods such as sputtering, electroplating, and photolithography are used to fabricate the rewiring layer on the upper surface, lower surface, or both sides of the substrate.

[0012] Furthermore, the RDL layer is composed of alternating stacks of precise metal wires and dielectric layers. The metal wires are made of copper, and the dielectric layers include... Or polyimide; Achieve high-density, fine-width / spacing electrical interconnects that far exceed the wiring capabilities of traditional PCBs or ceramic substrates.

[0013] The RDL termination corresponding to the RDL layer is equipped with a pad array for chip mounting and wire bonding, thereby constructing a complete, high-performance signal transmission network within the substrate plane to meet the requirements of low-loss, low-crosstalk transmission of high-speed, multi-channel electrical signals. Furthermore, the substrate surface is clearly divided into regions according to functional requirements, mainly including optical chip regions and electrical chip regions: In the photonic chip area, a mechanical alignment structure with micron-level precision is prefabricated on the surface of the silicon substrate using high-precision photolithography and anisotropic deep etching. The mechanical alignment structure is a V-groove, a U-groove, or a positioning boss with a vertical stop surface, used to assist in the passive mounting of optical chips.

[0014] Furthermore, a high aspect ratio through-hole array that penetrates or does not penetrate the substrate is prepared by deep reactive ion etching or laser drilling at the location directly below the heat source of the chip on the upper surface of the substrate.

[0015] Furthermore, the high aspect ratio via array is filled with high thermal conductivity pure copper or copper alloy through electroplating to form thermal vias or filled copper pillars. The thermal vias or filled copper pillars efficiently conduct the heat generated by the chip from the front side of the substrate to the back side with the shortest path and lowest thermal resistance, and then dissipate it through the system-level heat dissipation part, fundamentally solving the thermal management problem under high power density integration.

[0016] Furthermore, the support ring is made of silicon, ceramic, or glass, especially silicon, which has a coefficient of thermal expansion that matches that of the base plate material; It is a ring frame with a central through hole. The inner diameter determines the size of the internal cavity of the light engine, ensuring enough space to accommodate the light / electric chip. The height is determined by the optical working distance required from the light chip to the bottom of the lens cover and the arc height of the gold wire bonding line. The upper and lower end faces of the support ring are prepared with continuous and closed metallization layers through thin film deposition and patterning processes, and then eutectic solder is applied. The upper and lower end faces of the support ring serve as the docking interfaces for eutectic bonding with the lens cover and the substrate, respectively. During the bonding process, the solder melts, wets and solidifies to form a high-strength, non-porous alloy weld, thereby consolidating the three-layer structure into a whole and forming a lateral gas-tight wall. The corresponding support components form mechanical supports, establish hermetically sealed sidewalls, and precisely set the optical path distance.

[0017] Furthermore, the lens cover is a cover with an integrated lens, and the material is optical glass or silicon; The lens cover is located on the inner surface facing the chip and / or the outer surface facing the fiber array. It is fabricated using precision micro-nano methods, including hot pressing, grayscale lithography, reactive ion etching, or photoresist thermal reflow, and integrates a microlens array on a single chip. The surface shape of the lens can be customized according to specific optical path design requirements. It can be spherical or aspherical and is used for collimation or focusing of the beam. The edge region of the inner surface of the lens cover is prepared with a continuous and closed metallized ring through thin film deposition and patterning process; the position, width and metal layer are precisely corresponding to and complementary to the solder ring on the upper surface of the support ring below; during the eutectic bonding and encapsulation process, it interacts with the solder to form a strong and airtight alloy weld, thereby achieving the top airtight connection of the entire optical cavity while completing the optical function integration. The upper corresponding part forms an integrated optical function and sealing window, realizes optical conversion, and completes airtight sealing.

[0018] Furthermore, the lens cover is connected to an array of glass waveguides or fiber arrays via a waveguide / fiber coupling interface. The coupling end of the waveguide or fiber is precision polished into a 40°-50° bevel. The 40°-50° bevel causes the vertical optical path from / to the lens cover to undergo total internal reflection or specular reflection at the end face, achieving a 90° optical path reversal. Its MT end face can be processed to 8° to reduce back reflection. Arrayed glass waveguides are planar optical waveguide arrays fabricated on glass substrates by ion exchange or photolithography etching processes, and have mode field dimensions that match those of optical fibers. The arrayed glass waveguide or fiber array is fixed to the outer surface of the lens cover by UV-curing adhesive, laser welding or mechanical clamps.

[0019] Compared with existing technologies, this invention solves the problem of balancing airtightness, high-density integration, long-term reliability, and manufacturing cost in existing technologies through a modular, layered, and all-solid-state hermetically sealed packaging structure. It achieves a highly reliable, high-performance optical engine solution suitable for wafer-level mass production by using a three-layer stacked structure of "base plate-support ring-lens cover" and employing a metal eutectic bonding process to achieve hermetically sealed cavity packaging of the optoelectronic chip. Specifically: High airtightness and high reliability: All inorganic materials (silicon / glass / ceramics) + metal eutectic bonding achieve airtight packaging, completely isolating moisture and contaminants, and improving the lifespan of sensitive chips such as lasers; High integration: High-density electrical interconnection is achieved through RDL technology, supporting the integration of multi-channel optical engines to meet the needs of high-speed and high-capacity data transmission; High precision: By using semiconductor microfabrication processes (photolithography, etching, thin film deposition) to manufacture each layer of structure at the wafer level, the lens position, cavity height, and alignment marks can all be predefined with micron-level precision, achieving high-precision passive alignment between the chip and the lens, which is suitable for multi-channel array integration; Excellent thermal management and electrical performance: The silicon / ceramic substrate has good thermal conductivity, and the bottom surface is filled with copper thermal vias. The RDL can realize high-density electrical interconnection with low parasitic parameters to meet the requirements of high-speed electrical signal transmission. Suitable for mass production and with controllable costs: It can be manufactured and packaged in batches using wafer-level processes, which significantly reduces the packaging cost and time of a single device and has excellent potential for large-scale production. Modularity and flexibility: The three-layer structure can be designed and optimized independently. The support ring height is adjustable to accommodate different optical designs; the lens surface shape can be flexibly designed to optimize the beam pattern; the fiber optic coupling interface can be installed as an independent module, improving the overall adaptability of the solution. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the present invention.

[0021] Figure 2 This is an exploded view of the present invention.

[0022] Figure 3 This is a schematic diagram of application example 1 of the present invention.

[0023] Figure 4 This is a schematic diagram of application example 2 of the present invention.

[0024] Figure 5 This is a schematic diagram of application example 3 of the present invention.

[0025] Figure 6 This is a schematic diagram of application example 4 of the present invention.

[0026] Figure 7 This is a schematic diagram of application example 5 of the present invention. Detailed Implementation

[0027] Example:

[0028] Please see Figure 1-2 This embodiment demonstrates a high-airtightness optical engine, including a substrate 1, a support ring 2 disposed on the substrate 1, the middle of the support ring 2 being hollowed out, the middle of the hollowed-out support ring being used as a chip module setting area, and a chip module 3 being disposed within the chip module setting area; a lens cover 4 is disposed above the support ring 2; the support ring 2 is used as a seal between the substrate and the lens cover, and through the sealing effect of the support ring, the chip module setting area forms a high-airtightness sealed area, and the chip module is set within the high-airtightness sealed area, forming a three-layer stacked structure of "base plate-support ring-lens cover"; the support ring 2, substrate 1, and lens cover 4 are used to achieve airtight cavity encapsulation of the optoelectronic chip using a metal eutectic bonding process, forming a highly reliable, high-performance optical engine sealing structure suitable for wafer-level mass production; On the outer edge region of the upper surface of substrate 1, a continuous and closed annular metallization layer 10 is prepared by thin film deposition, including sputtering Ti / Pt / Au or Cr / Cu / Au and patterning process. The annular metallization layer, i.e. the sealing ring, forms the bonding interface of the bottom layer in the three-layer hermetic structure of "base plate-support ring-top cover" with subsequent eutectic bonding. The annular metallization layer ensures that the solder is fully wetted and forms a pore-free, high-strength, hermetic weld by ensuring uniformity, roughness and metallurgical compatibility.

[0029] The chip module 3 includes at least a set of optical chips 31 and electrical chips 32.

[0030] An RDL layer is provided on the substrate 1, which is formed by advanced semiconductor thin film methods such as sputtering, electroplating, and photolithography on the upper surface, lower surface, or both sides of the substrate.

[0031] The RDL layer is composed of alternating stacks of precise metal wires and dielectric layers. The metal wires are made of copper, and the dielectric layers include... Or polyimide; Achieve high-density, fine-width / spacing electrical interconnects that far exceed the wiring capabilities of traditional PCBs or ceramic substrates.

[0032] The RDL termination corresponding to the RDL layer is equipped with a pad array for chip mounting and wire bonding, thereby constructing a complete, high-performance signal transmission network within the substrate plane to meet the requirements of low-loss, low-crosstalk transmission of high-speed, multi-channel electrical signals. The surface of substrate 1 is clearly divided into regions according to functional requirements, mainly including the optical chip region and the electrical chip region: In the photonic chip area, a mechanical alignment structure with micron-level precision is prefabricated on the surface of the silicon substrate using high-precision photolithography and anisotropic deep etching. The mechanical alignment structure is a V-groove, a U-groove, or a positioning boss with a vertical stop surface, used to assist in the passive mounting of optical chips.

[0033] A high aspect ratio through-hole array 5 is prepared by deep reactive ion etching or laser drilling at the position directly below the heat source of the chip on the upper surface of substrate 1. It can penetrate or not penetrate the substrate.

[0034] The high aspect ratio through-hole array 5 is filled with high thermal conductivity pure copper or copper alloy through electroplating to form thermal through-holes or filled copper pillars. The thermal through-holes or filled copper pillars efficiently conduct the heat generated by the chip from the front side of the substrate to the back side with the shortest path and the lowest thermal resistance, and then dissipate it through the system-level heat dissipation part, fundamentally solving the thermal management problem under high power density integration.

[0035] The support ring 2 is made of silicon, ceramic or glass, especially silicon, which has a coefficient of thermal expansion that matches the base plate material. The support ring 2 is a ring frame with a central through hole. Its inner diameter determines the size of the internal cavity of the light engine, ensuring sufficient space to accommodate the light / electric chip. Its height is determined by the optical working distance required from the light chip to the bottom of the lens cover and the arc height of the gold wire bonding line. The upper and lower end faces of the support ring 2 are prepared with continuous and closed metallization layers through thin film deposition and patterning processes, and eutectic solder is then applied. The upper and lower end faces of the support ring 2 serve as the docking interfaces for eutectic bonding with the lens cover and the substrate, respectively. During the bonding process, the solder melts, wets and solidifies to form a high-strength, non-porous alloy weld, thereby consolidating the three-layer structure into a whole and forming a lateral gas-tight wall. The corresponding support components form mechanical supports, establish hermetically sealed sidewalls, and precisely set the optical path distance.

[0036] Lens cover 4 is a cover with an integrated lens, made of optical glass or silicon; The lens cover is located on the inner surface facing the chip and / or the outer surface facing the fiber array. It is fabricated using precision micro-nano methods, including hot pressing, grayscale lithography, reactive ion etching, or photoresist thermal reflow, and integrates a microlens array on a single chip. The surface shape of the lens can be customized according to specific optical path design requirements. It can be spherical or aspherical and is used for collimation or focusing of the beam. The edge region of the inner surface of the lens cover is prepared with a continuous and closed metallized ring 40 through thin film deposition and patterning process; the position, width and metal layer are precisely corresponding to and complementary to the solder ring on the upper surface of the support ring below; during the eutectic bonding packaging process, it interacts with the solder to form a strong and airtight alloy weld, thereby achieving the top airtight connection of the entire optical cavity while completing the optical function integration. The upper corresponding part forms an integrated optical function and sealing window, realizes optical conversion, and completes airtight sealing.

[0037] The lens cover 4 is connected to an arrayed glass waveguide 7 or a fiber array 8 with a standard MT interface via a waveguide / fiber coupling interface 6. The coupling end of the waveguide or fiber is precision polished into a 40°-50° bevel. The 40°-50° bevel causes the vertical light path from / to the lens cover to undergo total internal reflection or specular reflection at the end face, achieving a 90° light path reversal. Its MT end face can be processed into an 8° angle to reduce back reflection. Arrayed glass waveguides are planar optical waveguide arrays fabricated on glass substrates by ion exchange or photolithography etching processes, and have mode field dimensions that match those of optical fibers. The arrayed glass waveguide or fiber array is fixed to the outer surface of the lens cover by UV-curing adhesive, laser welding or mechanical clamps.

[0038] in: Key process feature: hermetically sealed connection Sealed bonding method: The three-layer structure of substrate-support ring-lens cover is bonded in one step or in succession by eutectic welding or reflow soldering through the metal solder system (such as AuSn eutectic solder, SnAgCu solder) prepared on its surface.

[0039] Sealing ring design: The metallization pattern on each layer is a closed ring. After the solder melts, it forms a continuous, non-porous metal sealing ring, thereby achieving full hermetic seal of the entire optical cavity. The water vapor permeability meets the MIL-STD-883 standard.

[0040] Overview of packaging process methods: Step 1 (Wafer-level front-end process): Process RDL, alignment marks, and metallization rings (which may contain eutectic solder) on silicon / ceramic substrate / glass substrate wafers respectively, and process thermally conductive vias filled with copper on the bottom surface; etch vias on the support ring wafer and metallize the upper and lower surfaces (which may contain eutectic solder); fabricate the lens array on the lens cover wafer by hot pressing, photoresist reflow, or etching, and then metallize it (which may contain eutectic solder).

[0041] Step 2 (Chip Mounting and Bonding): Divide the individual substrate or mount the optical and electrical chips directly onto the substrate wafer, and then perform gold wire bonding.

[0042] Step 3 (Stacked Eutectic Bonding): Align and stack the support ring and lens cap sequentially on the substrate (visual alignment or mechanical positioning can be used). In an inert gas (e.g., In a vacuum environment, by applying a certain temperature and pressure, the solder rings between each layer are melted, reflowed, and solidified simultaneously or sequentially to complete a one-time hermetically sealed assembly, forming a sealed unit containing a complete optical cavity.

[0043] Step 4 (Post-coupling): Align, couple, and fix the packaged optical engine unit with the glass waveguide / fiber array assembly.

[0044] In practical applications: Application Example 1: The airtight cavity adopts a three-layer discrete structure: See Figure 3 This application example uses a classic modular layered design.

[0045] Structural composition: The airtight cavity is composed of three discrete components stacked sequentially: substrate 1 (with RDL and chip), independent support ring 2 (frame), and independent lens cover 4 with integrated lens.

[0046] Assembly relationship: The support ring 2 is an independent mechanical spacer. Its upper and lower surfaces are bonded to the upper surface sealing ring of the base plate and the lower surface sealing ring of the lens cover through eutectic solder rings, respectively.

[0047] Process and Advantages: This structure features a clear division of labor in its manufacturing process, allowing each layer to be independently manufactured and tested at the wafer level, facilitating quality control. The height of the support ring can be flexibly changed to adapt to different optical working distance requirements, providing maximum design modularity and flexibility.

[0048] Application Example 2: Integrated structure of substrate and support ring + glass cover to create an airtight cavity: See Figure 4 This application example simplifies the number of components and assembly process through structural integration.

[0049] Structural Composition: The function of the support ring 2 is integrated with the substrate 1 in a unified design and fabrication. Specifically, on the substrate wafer, a raised wall with a specific height is directly fabricated around the optical chip area using deep silicon etching (DRIE) or ceramic precision machining. This wall serves as the support ring. Other areas of the substrate (including RDL, pads, and sealing ring) remain planar.

[0050] Assembly relationship: The lens cover 4 with lens is directly bonded to the sealing ring at the top of the integrated enclosure on the substrate by eutectic bonding, thus eliminating the need for a separate support ring component.

[0051] Process and Advantages: This solution reduces a single component and a single bonding interface, simplifying the supply chain and assembly process. The one-piece molding eliminates alignment errors between the support ring and the base plate, improving overall structural integrity. It is particularly suitable for large-scale, standardized products with strict limitations on package height and part number.

[0052] Application Example 3: Integrated structure of lens cover and support ring + substrate to construct airtight cavity: See Figure 5 This application example integrates the support function into the optical components, optimizing the top structure.

[0053] Structural Composition: The function of the support ring 2 is integrated with the lens cover 4 in a single design and manufacturing process. Specifically, a downwardly protruding annular or frame-shaped structure is fabricated on the back side (facing the chip side) of the glass or silicon-based lens cover wafer through precision molding, glass welding, or silicon etching. This structure not only integrates the lens in its central planar region, but its outer protruding portion itself provides the required support height.

[0054] Assembly Relationship: The lower surface (a flat annular surface) of the raised structure of the integrated top cover is directly bonded to the sealing ring on the upper surface of the substrate 1 via eutectic bonding. The inner space of the raised structure naturally forms an optical cavity.

[0055] Process and Advantages: This solution also reduces the number of components and bonding interfaces. It integrates optical components with mechanical supports, potentially reducing the overall package thickness. (Bump junction) Application Example 4: Hermetic Transceiver Assembly with Integrated Glass Waveguide: See Figure 6 This application example expands the optical path integration and functionality outside the airtight cavity.

[0056] Structural Composition: A glass waveguide component 7 is further integrated onto the standard hermetically sealed optical engine constructed using applications 1, 2, or 3. This component is not a simple fiber array, but a planar optical waveguide (PLC) fabricated on a glass substrate using ion exchange or photolithography etching processes. This PLC can integrate passive devices such as beam splitters, multiplexers, optical switches, and attenuators.

[0057] Coupling method: The glass waveguide assembly is fixed to the outside of the lens cover using high-precision clamps or adhesive bonding. The waveguide's input / output ports are precisely aligned with the lens array on the cover. The optical path is: chip inside the hermetically sealed cavity → lens on the cover → glass waveguide → external optical fiber.

[0058] Advantages: This solution maintains the core's airtightness while achieving monolithic integration of the chip with complex passive optical paths, greatly enhancing the signal processing capabilities of the optical engine (such as wavelength division multiplexing / demultiplexing), making it suitable for more complex system applications.

[0059] Application Example 5: Compact Module for Directly Coupled Fiber Arrays: See Figure 7 Structural composition: On the standard airtight optical engine constructed in Embodiments 1, 2 or 3, a fiber array 8 (FA) with a standard MT interface is used as the final output / input interface.

[0060] Coupling and Fixing: The end faces of the fiber array are aligned actively or passively to directly couple each channel to the lens array on the lens cover. Fixing methods include low-shrinkage UV adhesive bonding or local laser welding (when the FA has a metal sleeve and the edge of the cover has a corresponding metallized area).

[0061] Advantages: This solution constitutes a complete "plug-and-play" optical transceiver submodule. It provides a complete solution from electrical interfaces to standard fiber optic interfaces, with the highest level of integration, facilitating direct integration by clients. It is the ideal form of internal optical engine for current high-speed optical modules in data centers (such as QSFP-DD, OSFP).

[0062] Compared with existing technologies, this invention solves the problem of balancing airtightness, high-density integration, long-term reliability, and manufacturing cost in existing technologies through a modular, layered, and all-solid-state hermetically sealed packaging structure. It achieves a highly reliable, high-performance optical engine solution suitable for wafer-level mass production by using a three-layer stacked structure of "base plate-support ring-lens cover" and employing a metal eutectic bonding process to achieve hermetically sealed cavity packaging of the optoelectronic chip. Specifically: High airtightness and high reliability: All inorganic materials (silicon / glass / ceramics) + metal eutectic bonding achieve airtight packaging, completely isolating moisture and contaminants, and improving the lifespan of sensitive chips such as lasers; High integration: High-density electrical interconnection is achieved through RDL technology, supporting the integration of multi-channel optical engines to meet the needs of high-speed and high-capacity data transmission; High precision: By using semiconductor microfabrication processes (photolithography, etching, thin film deposition) to manufacture each layer of structure at the wafer level, the lens position, cavity height, and alignment marks can all be predefined with micron-level precision, achieving high-precision passive alignment between the chip and the lens, which is suitable for multi-channel array integration; Excellent thermal management and electrical performance: The silicon / ceramic substrate has good thermal conductivity, and the bottom surface is filled with copper thermal vias. The RDL can realize high-density electrical interconnection with low parasitic parameters to meet the requirements of high-speed electrical signal transmission. Suitable for mass production and with controllable costs: It can be manufactured and packaged in batches using wafer-level processes, which significantly reduces the packaging cost and time of a single device and has excellent potential for large-scale production. Modularity and flexibility: The three-layer structure can be designed and optimized independently. The support ring height is adjustable to accommodate different optical designs; the lens surface shape can be flexibly designed to optimize the beam pattern; the fiber optic coupling interface can be installed as an independent module, improving the overall adaptability of the solution.

[0063] For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A high-airtightness light engine, characterized in that: The system includes a substrate with a support ring on it. The support ring has a hollow center, and the middle part of the hollow center serves as a chip module setting area, within which a chip module is installed. A lens cover is located above the support ring. The support ring acts as a seal between the substrate and the lens cover. Through the sealing effect of the support ring, the chip module setting area forms a highly airtight sealed area. Chip modules are installed within this highly airtight sealed area, forming a three-layer stacked structure of "base plate-support ring-lens cover". The support ring, substrate, and lens cover are bonded together using a metal eutectic bonding process to achieve airtight cavity encapsulation of the optoelectronic chip, forming a highly reliable, high-performance optical engine sealing structure suitable for wafer-level mass production. On the outer edge of the substrate's upper surface, a continuous, closed annular metallization layer is prepared by thin film deposition, including sputtering Ti / Pt / Au or Cr / Cu / Au and patterning processes. The annular metallization layer, also known as the sealing ring, forms the bonding interface at the bottom layer of the three-layer hermetic structure of "base plate-support ring-top cover" through subsequent eutectic bonding. The annular metallization layer ensures that the solder is fully wetted and forms a pore-free, high-strength, hermetic weld through its uniformity, roughness, and metallurgical compatibility.

2. The high airtightness light engine according to claim 1, characterized in that: The chip module includes at least a set of optical chips and electrical chips.

3. A high-airtightness light engine according to claim 1 or 2, characterized in that: An RDL layer is provided on the substrate, which is formed by advanced semiconductor thin film methods such as sputtering, electroplating, and photolithography on the upper surface, lower surface, or both sides of the substrate.

4. A high-airtightness light engine according to claim 3, characterized in that: The substrate surface is clearly divided into regions according to functional requirements, mainly including the optical chip region and the electrical chip region: In the photonic chip area, a mechanical alignment structure with micron-level precision is prefabricated on the surface of the silicon substrate using high-precision photolithography and anisotropic deep etching. The mechanical alignment structure is a V-groove, a U-groove, or a positioning boss with a vertical stop surface, used to assist in the passive mounting of optical chips.

5. A high-airtightness light engine according to claim 4, characterized in that: A high aspect ratio through-hole array is prepared by deep reactive ion etching or laser drilling at the position directly below the heat source of the chip on the upper surface of the substrate. It can penetrate or not penetrate the substrate.

6. A high-airtightness light engine according to claim 5, characterized in that: The high aspect ratio through-hole array is filled with high thermal conductivity pure copper or copper alloy through electroplating to form thermal through-holes or filled copper pillars. The thermal through-holes or filled copper pillars efficiently conduct the heat generated by the chip from the front side of the substrate to the back side with the shortest path and the lowest thermal resistance, and then dissipate it through the system-level heat dissipation part, fundamentally solving the thermal management problem under high power density integration.

7. A high-airtightness light engine according to claim 6, characterized in that: The support ring is made of silicon, ceramic, or glass, especially silicon, whose coefficient of thermal expansion matches that of the base plate material. The support ring is a ring frame with a central through hole. The inner diameter determines the size of the internal cavity of the light engine, ensuring sufficient space to accommodate the light / electric chip. The height is determined by the optical working distance required from the light chip to the bottom of the lens cover and the arc height of the gold wire bonding line. The upper and lower end faces of the support ring are prepared with continuous and closed metallization layers through thin film deposition and patterning processes, and then eutectic solder is applied. The upper and lower end faces of the support ring serve as the docking interfaces for eutectic bonding with the lens cover and the substrate, respectively. During the bonding process, the solder melts, wets and solidifies to form a high-strength, non-porous alloy weld, thereby consolidating the three-layer structure into a whole and forming a lateral gas-tight wall. The corresponding support components form mechanical supports, establish hermetically sealed sidewalls, and precisely set the optical path distance.

8. A high-airtightness light engine according to claim 7, characterized in that: The lens cover is a cover with an integrated lens, and the material is optical glass or silicon; The lens cover is located on the inner surface facing the chip and / or the outer surface facing the fiber array. It integrates a microlens array monolithically through precision micro-nano fabrication methods, including hot pressing, grayscale lithography, reactive ion etching, or photoresist thermal reflow. The surface shape of the lens can be customized according to specific optical path design requirements, and can be spherical or aspherical, for collimation or focusing of the beam.

9. A high-airtightness light engine according to claim 8, characterized in that: The inner surface edge region of the lens cover is fabricated with a continuous, closed metallized ring through thin film deposition and patterning processes; the position, width, and metal layer of the metal ring precisely correspond to and complement the solder ring on the upper surface of the support ring below. During the eutectic bonding process, it interacts with the solder to form a strong and hermetic alloy weld, thereby achieving hermetic sealing of the top of the entire optical cavity while completing the integration of optical functions. The upper corresponding part forms an integrated optical function and sealing window, realizes optical conversion, and completes airtight sealing.

10. A high-airtightness light engine according to claim 9, characterized in that: The lens cover is connected to an array of glass waveguides or fiber arrays via a waveguide / fiber coupling interface. The coupling end of the waveguide or fiber is precision polished into a 40°-50° bevel. The 40°-50° bevel causes the vertical light path from / to the lens cover to undergo total internal reflection or specular reflection at the end face, achieving a 90° light path reversal. Its MT end face can be processed to 8° to reduce back reflection. Arrayed glass waveguides are planar optical waveguide arrays fabricated on glass substrates by ion exchange or photolithography etching processes, and have mode field dimensions that match those of optical fibers. The arrayed glass waveguide or fiber array is fixed to the outer surface of the lens cover by UV-curing adhesive, laser welding or mechanical clamps.

Images