Multi-channel multi-beam double-sided lead-out radio frequency micro-module based on DPC packaging substrate

Abstract

The invention discloses a multi-channel multi-beam double-sided lead-out radio frequency micro-module based on a DPC packaging substrate. The multi-channel multi-beam double-sided lead-out radio frequency micro-module comprises a multi-channel multi-beam radio frequency unit, a power management unit and a DPC packaging tube shell, a metal layer is arranged on the side wall of a substrate of the DPC packaging tube shell, and the metal layer and the grounding metal layers on the upper surface and the lower surface jointly form an electromagnetic shielding cavity. An electromagnetic band gap structure is integrated on the surface of the upper substrate; and the lower substrate is connected with a resistance potential-divider network and a power amplifier chip through a gold bump array in an inverted buckling manner. Through the synergistic effect of metallization of the side wall of the substrate, the electromagnetic band gap structure and flip chip connection, a multi-stage electromagnetic isolation barrier is constructed, the problems of signal leakage and insufficient isolation are solved, and the high-density integration and double-sided lead-out functions of the micro module are realized.

Description

Technical Field

[0001] This invention relates to microwave and millimeter-wave microsystems, and more particularly to a multi-channel, multi-beam, double-sided lead-out radio frequency micromodule based on a DPC package substrate. Background Technology

[0002] Satellite communication, as a key component of modern communication networks, plays an irreplaceable role in realizing 6G terrestrial-space integration and the Internet of Things (IoT). Traditional terrestrial communication is limited by geographical conditions, while satellite communication systems, through inter-satellite links and coordination with ground stations, can achieve efficient coverage of blind spots such as oceans and deserts. In recent years, the rise of low-Earth orbit (LEO) satellite constellations has further promoted the development of high-throughput and low-latency satellite communication. Among these, phased array antenna systems, as crucial on-board payloads, are an indispensable core component ensuring satellite communication.

[0003] As satellite communications develop towards low-Earth orbit constellations and high throughput, phased array antenna systems, as core on-board payloads, place stringent requirements on the integration density of front-end modules, signal isolation, and electromagnetic compatibility.

[0004] The invention patent with announcement number CN118943136B discloses a high-reliability, high-power three-dimensional heterogeneous integrated radio frequency antenna microsystem. It uses a DPC substrate and a copper-based three-dimensional structure to realize the vertical transmission and hermetically sealed packaging of radio frequency signals, and realizes a 2.5D×2 stacked architecture through a two-stage SiC adapter board.

[0005] However, this solution still has shortcomings in electromagnetic shielding: First, the sidewalls of its DPC substrate lack metal coverage due to limitations in planar fabrication technology, becoming a weak point in electromagnetic shielding, allowing high-frequency signals to easily couple and leak from the substrate sidewalls; second, the chips on its substrate mainly rely on wire bonding for interconnection, and long leads can easily become radiating antennas at high frequencies, with more leads resulting in more severe crosstalk between channels; third, the substrate surface has difficulty suppressing the propagation of parasitic modes at the radiation field level. These defects are particularly prominent in multi-channel and high-density integration scenarios, limiting its application in phased array antenna arrays and other applications requiring extremely high isolation. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a multi-channel, multi-beam, double-sided lead-out radio frequency micro-module based on a DPC packaging substrate, which has high integration density and excellent electromagnetic shielding performance.

[0007] Technical Solution: The multi-channel, multi-beam, double-sided lead-out RF micro-module based on a DPC package substrate of the present invention includes a multi-channel, multi-beam RF unit, a power management unit, and a DPC package shell. The substrate sidewall of the DPC package shell is provided with a metal layer, and the metal layer on the substrate sidewall is electrically connected to the grounded metal layer on the upper and lower surfaces of the DPC package shell to form an electromagnetic shielding cavity. The upper substrate surface of the DPC package shell integrates an electromagnetic bandgap structure for suppressing signal transmission in the substrate and radiation in space. The lower substrate of the DPC package shell is connected to a resistor voltage divider network and a power amplifier chip by a gold bump array.

[0008] By incorporating a metal layer on the sidewall of the DPC package substrate, and ensuring reliable electrical connection between this metal layer and the grounded metal layers on the upper and lower surfaces of the DPC package, a complete Faraday cage structure—a fully enclosed electromagnetic shielding cavity—is formed. This structure addresses the weak point in electromagnetic shielding caused by the lack of metal coverage on the sidewalls of existing DPC packages. It effectively blocks the path of high-frequency signal coupling and leakage from the substrate sidewalls, completely confining internal electromagnetic signals within the cavity. This achieves broadband suppression of external electromagnetic interference and effective constraint of strong internal signal leakage.

[0009] By integrating an electromagnetic bandgap structure on the surface of the upper substrate, the parasitic transmission path of spatial electromagnetic waves between dielectric layers can be effectively cut off from the radiation field level, suppressing the lateral propagation of signals inside the substrate and suppressing the radiative coupling of signals in space, thus achieving radiation suppression in a wide frequency band and electromagnetic isolation from both conduction and radiation paths.

[0010] On the lower substrate, a resistor divider network and a power amplifier chip are connected inverted via a gold bump array. The gold bump array achieves the shortest physical and electrical transmission path between the chip and the substrate, significantly reducing parasitic inductance and capacitance. Furthermore, reducing leads also reduces crosstalk between channels, ensuring high-fidelity transmission of high-frequency signals. At the same time, the densely distributed gold bump array forms a low-impedance distributed grounding network, effectively suppressing near-field coupling and crosstalk within the chip and between the chip and the substrate, thus improving electromagnetic compatibility from the chip source.

[0011] The above three technical features work together to build a multi-layered and comprehensive electromagnetic protection system from the module shell (sidewall metallization), substrate surface (electromagnetic bandgap structure) to chip interconnect layer (flip-chip gold bumps). They work together on the conduction path and radiation path, solving the signal leakage and crosstalk problems caused by the lack of sidewall shielding, substrate parasitic mode and lead wire parasitic radiation in the prior art. This achieves high isolation and high-density integration of the micro-module and excellent electromagnetic compatibility performance.

[0012] By setting a metal layer on the sidewall of the DPC package substrate, together with the grounded metal layers on the upper and lower surfaces, a complete electromagnetic shielding cavity is formed, solving the signal leakage problem caused by the lack of metal coverage on the sidewalls of existing DPC packages. By integrating an electromagnetic bandgap structure on the surface of the upper substrate, the parasitic transmission path of spatial electromagnetic waves between dielectric layers can be effectively cut off from the radiation field level. By flip-chip connecting the resistor voltage divider network and the power amplifier chip on the lower substrate, and using a gold bump array to achieve the shortest electrical interconnection path between the chip and the substrate, parasitic parameters are significantly reduced and high-frequency performance is improved.

[0013] Preferably, the upper substrate and the lower substrate are respectively integrated with dams and copper pillars below and above them, the upper and lower dams are joined to form an isolation cavity, and the upper and lower copper pillars are joined to form a micro coaxial transmission structure for signal transmission between the upper and lower substrates.

[0014] The upper and lower dams are connected to form an isolation cavity, which realizes physical isolation between different functional units and the blocking of spatial electromagnetic fields; the upper and lower copper pillars are connected to form a micro coaxial transmission structure, which provides a continuous, low-loss, and highly shielded vertical transmission channel for radio frequency signals from the plane to space, realizing the dual-sided signal output function.

[0015] Preferably, the electromagnetic bandgap structure is composed of periodically arranged metal patterns, which form a high-impedance surface within a specific operating frequency band.

[0016] The electromagnetic bandgap structure is composed of periodic metallic patterns. Its design is flexible and the period size can be adjusted according to the operating frequency band to form a precise high-impedance surface, thereby achieving efficient radiation suppression in a specific frequency band.

[0017] Preferably, the upper and lower substrates are internally integrated with a solid copper hole array, which is used to realize signal transmission between the upper and lower layers of the substrate and to form an electromagnetic isolation structure.

[0018] By integrating solid copper via arrays inside the upper and lower substrates, not only is vertical signal transmission between the upper and lower layers of the substrate achieved, but the densely arranged copper via arrays also form an equivalent electromagnetic isolation wall, blocking near-field coupling and energy leakage between adjacent RF channels and between RF channels and power channels.

[0019] Preferably, the multi-channel multi-beam RF unit includes a transmission structure on the lower substrate for RF signal input, a heterogeneous amplitude-phase multifunctional chip, a power amplifier chip, and a transmission structure on the upper substrate for RF signal output; the heterogeneous amplitude-phase multifunctional chip includes a Si-based multi-beam multifunctional amplitude-phase chip and a first SiC adapter board, and the Si-based multi-beam multifunctional amplitude-phase chip is connected to the first SiC adapter board by a gold bump array.

[0020] The heterogeneous amplitude-phase multifunctional chip adopts a gold bump flip-chip structure, which realizes a high-strength mechanical connection and low parasitic electrical interconnection between the Si-based multi-beam multifunctional amplitude-phase chip and the first SiC adapter board. At the same time, the gold bump array forms a distributed grounding shielding network, which effectively suppresses electromagnetic coupling between different circuits inside the chip.

[0021] Preferably, the power management unit includes a heterogeneous power chip and a resistor divider network, with the heterogeneous power chip vertically stacked on the back of the heterogeneous amplitude-phase multifunctional chip; the heterogeneous power chip includes a second SiC adapter board and a Si-based gate regulator chip, a Si-based low-dropout linear regulator chip, and a Si-based power modulation chip connected thereon by a gold bump array.

[0022] The power management unit is vertically stacked on the back of the heterogeneous amplitude-phase multi-functional chip, which makes great use of the vertical space and reduces the planar area of ​​the micro-module. The heterogeneous power chip integrates power chips with different functions through gold bump flip-chip, realizing high-density integration and physical isolation of power functions.

[0023] Preferably, BGA solder balls for interconnecting with an antenna and interconnecting with a PCB are integrated above the upper substrate and below the lower substrate, respectively.

[0024] By integrating BGA solder balls on the upper and lower substrates, the dual-sided lead-out function of the micro-module is realized. The BGA solder balls on the lower substrate are used for interconnection with the PCB substrate, while the BGA solder balls on the upper substrate can be directly interconnected with the antenna radiating unit, forming an integrated antenna-micro-module unit, which improves the system's integration density and scalability.

[0025] Preferably, the upper substrate, lower substrate, dam, and metal layer on the sidewall of the substrate together form a sealed cavity, realizing the hermetically sealed packaging and fully enclosed electromagnetic shielding of the micro-module.

[0026] The upper substrate, lower substrate, surrounding dam, and metal layer on the side wall of the substrate together form a sealed cavity. This cavity has the dual functions of hermetic sealing and electromagnetic shielding, providing an isolated environment for the internal chip and forming a fully enclosed electromagnetic protection.

[0027] Preferably, the radio frequency micro-module includes a multi-level electromagnetic isolation barrier, wherein the gold bump array inside the chip constitutes the first-level isolation barrier, the electromagnetic bandgap structure constitutes the second-level isolation barrier, the isolation cavity formed by the dam constitutes the third-level isolation barrier, and the sealed cavity formed by the metallization layer on the sidewall of the substrate constitutes the fourth-level isolation barrier.

[0028] A collaborative protection system with four levels of electromagnetic isolation barriers was constructed, progressing layer by layer from the inside of the chip, the surface of the substrate, the isolation cavity to the outer shell of the module, covering the entire path of conduction and radiation, and providing sufficient electromagnetic compatibility margin for high isolation and high density integrated multi-channel multi-beam micro-modules.

[0029] Preferably, the first SiC adapter board of the heterogeneous phase-multifunctional chip is bonded to the lower substrate with conductive adhesive and electrically interconnected with the lower substrate by wire bonding.

[0030] Beneficial effects: By introducing substrate sidewall metallization, upper substrate electromagnetic bandgap structure and chip flip-chip interconnect technology, this invention constructs a multi-level electromagnetic shielding system based on the existing DPC three-dimensional heterogeneous integration architecture, solving the problems of signal leakage and insufficient isolation in the prior art. At the same time, it realizes high-density integration and double-sided lead-out function of micro-modules, significantly improving the reliability and engineering practicality of the product. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view of the radio frequency micro-module of the present invention;

[0032] Figure 2 This is a top view of the radio frequency micro-module of the present invention;

[0033] Figure 3 This is a bottom view of the radio frequency micro-module of the present invention;

[0034] Figure 4 This is a bottom view of the upper substrate of the radio frequency micro-module of the present invention;

[0035] Figure 5 This is a top view of the lower substrate of the radio frequency micro-module of the present invention.

[0036] The following are the labels in the figure: 1. Upper substrate, 2. Lower substrate, 3. Resistor voltage divider network, 4. Power amplifier chip, 5. Dam, 6. Copper pillar, 7. Solid copper hole, 8. Si-based multi-beam multi-function amplitude and phase chip, 9. First SiC adapter board, 10. Second SiC adapter board, 11. Si-based gate regulator chip, 12. Si-based low dropout linear regulator chip, 13. Si-based power modulation chip, 14. BGA solder ball, 15. Wire bonding. Detailed Implementation

[0037] As shown in the figure, the multi-channel, multi-beam, double-sided lead-out RF micro-module based on a DPC package substrate of the present invention includes a multi-channel, multi-beam RF unit, a power management unit, and a DPC package shell. The substrate sidewall of the DPC package shell is provided with a metal layer, and the metal layer on the substrate sidewall is electrically connected to the grounded metal layer on the upper and lower surfaces of the DPC package shell to form an electromagnetic shielding cavity. The surface of the upper substrate 1 of the DPC package shell is integrated with an electromagnetic bandgap structure for suppressing signal transmission in the substrate and radiation in space. The lower substrate 2 of the DPC package shell is connected to a resistor voltage divider network 3 and a power amplifier chip 4 by a gold bump array.

[0038] The DPC package employs a unibody molded ceramic package structure, comprising a lower shell and an upper shell, which are vertically stacked to form a sealed cavity. The multi-channel, multi-beam RF unit and power management unit are both integrated within this sealed cavity.

[0039] The upper substrate 1 and the lower substrate 2 have dams 5 and copper pillars 6 integrated below and above them, respectively. After the upper substrate 1 and the lower substrate 2 are connected, the upper and lower dams 5 are connected to form an isolation cavity, which physically separates the different functional units inside the micro-module and effectively blocks the propagation path of the spatial electromagnetic field; the upper and lower copper pillars 6 are connected to form a micro coaxial transmission structure, realizing low-loss and high-shield transmission of radio frequency signals in the vertical direction.

[0040] An electromagnetic bandgap structure is integrated on the surface of the upper substrate 1. This electromagnetic bandgap structure consists of periodically arranged metal patterns, such as metal patches or metal meshes, which form a high-impedance surface within a specific operating frequency band, effectively blocking the lateral conduction of signals through the substrate and suppressing radiative coupling of signals in space. The electromagnetic bandgap structure is existing technology, and the arrangement of the metal patterns can be customized to achieve different suppression effects according to actual needs.

[0041] The DPC package's substrate sidewalls are equipped with metal layers, including upper and lower substrate sidewall metal layers. These metal layers are electrically connected to the grounded metal layers on the upper and lower surfaces of the DPC package, together forming a complete Faraday cage structure, i.e., a complete electromagnetic shielding cavity. This cavity not only achieves hermetically sealed packaging of the micromodule but also completely confines the internal electromagnetic signals within the cavity, eliminating the possibility of signal leakage from the sidewalls. Because individual substrates are relatively thin, sidewall metallization is not feasible. This is essentially due to the manufacturing process; the substrate is fabricated as a large wafer, and all process steps are performed on the front and back sides. The sides, due to their irregular shape and thinness, lack the foundation for processing. However, after the upper and lower packages achieve hermetically sealed packaging using gold-solder bonding, the entire RF micromodule forms a single unit with sufficient thickness for processing, allowing the formation of metal layers on the substrate sidewalls.

[0042] A resistor divider network 3 and a power amplifier chip 4 are connected to the lower substrate 2 via a gold bump array. The power amplifier chip 4 and the resistor divider network 3 are flipped onto the lower substrate 2 via the gold bump array, achieving the shortest physical and electrical transmission path between the chip and the substrate. This significantly reduces parasitic inductance and capacitance, ensuring high-fidelity transmission of high-frequency signals. The resistor divider network 3 and the power amplifier chip 4 are compound chips. For compound chips, the application challenges lie in grounding reliability and the suppression of high-frequency parasitic signals. The ground plane of a compound chip is usually located on the back side of the chip. In traditional mounting processes, the chip is directly bonded to the casing using conductive adhesive or eutectic bonding. The back metal ground plane forms a tight physical contact with the substrate ground layer, creating a low-impedance and low-inductance RF return path. With this mounting method, the ground potential is stable, and signal energy is transmitted efficiently. However, with the continuous improvement of system integration, flip-chip technology is becoming increasingly popular due to its shorter interconnect paths and smaller parasitic effects. But in flip-chip packaging, the chip is flipped so that the back side faces upwards, and the back metal ground plane becomes suspended. This suspended metal plane can generate unnecessary capacitive coupling at high frequencies, causing serious signal integrity problems.

[0043] This invention utilizes chip modeling technology to construct a model of an RF micro-module. Through repeated simulations and optimizations, the optimal selection of key dimensions such as cavity depth and bonding finger height at the package fabrication level is confirmed, creating predictable electromagnetic boundary conditions for flip-chip development. This allows for precise quantification of the distance between the back metal plane and the bottom of the package after flip-chip fabrication, thereby converting the equivalent capacitance into controllable circuit parameters. Simultaneously, during chip simulation modeling, precise electromagnetic models are established for the chip's metal layer and dielectric layer structures. The optimal placement and quantity of gold bumps (gold balls) are confirmed through simulation optimization using these electromagnetic models, ensuring the best grounding effect within the target frequency band and avoiding the introduction of additional parasitic effects. Grounding of gold bumps at key locations achieves a good connection of the ground plane, allowing compound chips to maintain the inherent advantages of low parasitics and high density in flip-chip applications.

[0044] The multi-channel multi-beam RF unit includes a transmission structure for RF signal input on the lower substrate 2, a heterogeneous amplitude-phase multifunctional chip, a power amplifier chip 4, and a transmission structure for RF signal output on the upper substrate 1. The heterogeneous amplitude-phase multifunctional chip includes a Si-based multi-beam multifunctional amplitude-phase chip 8 and a first SiC adapter board 9. The Si-based multi-beam multifunctional amplitude-phase chip 8 is invertedly connected to the first SiC adapter board 9 via a gold bump array. The first SiC adapter board 9 is bonded to the lower substrate 2 with conductive adhesive and electrically interconnected with the lower substrate 2 via wire bonding 15.

[0045] The power management unit includes a heterogeneous power chip and a resistor divider network 3. The heterogeneous power chips are vertically stacked on the back of the heterogeneous amplitude-phase multifunctional chip and fixed by conductive adhesive. The heterogeneous power chips include a second SiC adapter board 10 and a Si-based gate regulator chip 11, a Si-based low-dropout linear regulator chip 12, and a Si-based power modulation chip 13 connected to it by an array of gold bumps, achieving high-density integration and physical isolation of power functions.

[0046] The upper substrate 1 and the lower substrate 2 have an integrated array of solid copper vias 7. The array of solid copper vias 7 is used to realize signal transmission between the upper and lower layers of the substrate. At the same time, the dense arrangement forms an equivalent electromagnetic isolation wall, which effectively blocks near-field coupling and energy leakage between adjacent RF channels and between RF channels and power channels.

[0047] BGA solder balls 14 are integrated on the upper substrate 1 and the lower substrate 2 respectively. The BGA solder balls 14 on the upper substrate 1 are used to interconnect with the antenna radiating unit, and the BGA solder balls 14 on the lower substrate 2 are used to interconnect with the external PCB, thereby forming an integrated antenna-micro-module unit and realizing the double-sided lead-out function of the micro-module.

[0048] Based on the above structure, this embodiment constructs a four-level electromagnetic isolation barrier: the first level is the gold bump array inside the chip, which blocks near-field coupling and crosstalk within the chip; the second level is the electromagnetic bandgap structure on the surface of the upper substrate, which suppresses parasitic transmission of the radiated field; the third level is the isolation cavity formed by the docking of the upper and lower dams, which blocks the near-field coupling path of the spatial electromagnetic field; the fourth level is a sealed cavity composed of the metal layer on the sidewall of the substrate and the grounding layers on the upper and lower surfaces, which forms a complete Faraday cage, achieving broadband suppression of electromagnetic interference from the external environment and constraint of strong signals inside. The four levels work synergistically to construct an electromagnetic protection scheme covering the entire conduction and radiation path, providing sufficient electromagnetic compatibility margin for high-isolation and high-density integrated multi-channel multi-beam micro-modules.

Claims

1. A multi-channel, multi-beam, double-sided lead-out RF micro-module based on a DPC package substrate, comprising a multi-channel, multi-beam RF unit, a power management unit, and a DPC package, characterized in that: The substrate sidewall of the DPC package shell is provided with a metal layer, and the metal layer of the substrate sidewall is electrically connected with the grounded metal layer on the upper and lower surfaces of the DPC package shell to form an electromagnetic shielding cavity; the surface of the upper substrate (1) of the DPC package shell is integrated with an electromagnetic bandgap structure for suppressing signal transmission in the substrate and radiation in space; the lower substrate (2) of the DPC package shell is connected to a resistor voltage divider network (3) and a power amplifier chip (4) by a gold bump array.

2. The radio frequency micro-module according to claim 1, characterized in that: The upper substrate (1) and the lower substrate (2) are respectively equipped with a dam (5) and a copper pillar (6) below and above them. The upper and lower dams (5) are joined to form an isolation cavity, and the upper and lower copper pillars (6) are joined to form a micro coaxial transmission structure for signal transmission between the upper and lower substrates.

3. The radio frequency micro-module according to claim 1, characterized in that: The electromagnetic bandgap structure is composed of periodically arranged metal patterns, which form a high-impedance surface within a specific operating frequency band.

4. The radio frequency micro-module according to claim 1, characterized in that: The upper substrate (1) and the lower substrate (2) are internally integrated with a solid copper hole (7) array. The solid copper hole (7) array is used to realize signal transmission between the upper and lower layers of the substrate and to form an electromagnetic isolation structure.

5. The radio frequency micro-module according to claim 1, characterized in that: The multi-channel multi-beam radio frequency unit includes a transmission structure for radio frequency signal input on the lower substrate (2), a heterogeneous amplitude and phase multifunctional chip, a power amplifier chip (4), and a transmission structure for radio frequency signal output on the upper substrate (1). The heterogeneous amplitude and phase multifunctional chip includes a Si-based multi-beam multifunctional amplitude and phase chip (8) and a first SiC adapter board (9). The Si-based multi-beam multifunctional amplitude and phase chip (8) is connected to the first SiC adapter board (9) by a gold bump array.

6. The radio frequency micro-module according to claim 5, characterized in that: The power management unit includes a heterogeneous power chip and a resistor divider network (3). The heterogeneous power chip is vertically stacked on the back of the heterogeneous amplitude-phase multifunctional chip. The heterogeneous power chip includes a second SiC adapter board (10) and a Si-based gate regulator chip (11), a Si-based low-dropout linear regulator chip (12), and a Si-based power modulation chip (13) connected to it by a gold bump array.

7. The radio frequency micro-module according to claim 1, characterized in that: BGA solder balls (14) for interconnecting with the antenna and interconnecting with the PCB are integrated above the upper substrate (1) and below the lower substrate (2), respectively.

8. The radio frequency micro-module according to claim 2, characterized in that: The upper substrate (1), lower substrate (2), dam (5) and metal layer on the sidewall of the substrate together form a sealed cavity, realizing the hermetically sealed packaging and fully enclosed electromagnetic shielding of the micro-module.

9. The radio frequency micro-module according to claim 2, characterized in that: The radio frequency micro-module includes multiple levels of electromagnetic isolation barriers. The gold bump array inside the chip constitutes the first level of isolation barrier, the electromagnetic bandgap structure constitutes the second level of isolation barrier, the isolation cavity formed by the dam constitutes the third level of isolation barrier, and the sealed cavity formed by the metallization layer on the sidewall of the substrate constitutes the fourth level of isolation barrier.

10. The radio frequency micro-module according to claim 5, characterized in that: The first SiC adapter board (9) of the heterogeneous phase-multifunctional chip is bonded to the lower substrate (2) with conductive adhesive and electrically interconnected with the lower substrate (2) by wire bonding (15).

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