Multi-option collaborative matching structure and design method for radio frequency substrate plastic package

Abstract

The application provides a multi-option cooperative matching structure and design method for radio frequency substrate plastic packaging, relates to the technical field of semiconductor packaging, and comprises an organic packaging substrate and a radio frequency chip; the radio frequency chip is attached to the organic packaging substrate, bonding wires are arranged between the pins of the organic packaging substrate and the radio frequency chip, a plurality of candidate bonding pads are arranged on the organic packaging substrate, and the pins of the radio frequency chip are arranged in correspondence with at least two physically separated candidate bonding pads; each candidate bonding pad is connected to a signal network node or a passive matching element through built-in metal traces on the organic packaging substrate. The application has the advantages of great matching precision and flexibility, high performance predictability and consistency, strong universality, adaptation to high-density plastic packaging design, good process compatibility and reduced technical transformation cost.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and more specifically, to a multi-option cooperative matching structure and design method for radio frequency substrate molding. Background Technology

[0002] As wireless communication technology advances towards higher frequencies and greater integration, the performance of radio frequency (RF) chips becomes increasingly reliant on packaging technology. Molded substrate packaging, with its high-density wiring capabilities, excellent signal integrity, and relatively low cost, has become the mainstream packaging form for mid-to-high frequency RF devices. In this type of packaging, the pins of the RF chip are electrically connected to pads on the packaging substrate via bonding wires, and then connected to external solder balls or pins through interconnects within the substrate. Finally, the molding compound provides mechanical protection and environmental isolation. However, the bonding wires introduce a significant amount of parasitic series inductance along the RF signal transmission path. This inductance is a key factor contributing to impedance mismatch, signal reflection, increased insertion loss, and deteriorated noise figure (NF). Therefore, accurate impedance matching of package parasitic parameters, including the gold wire inductance, is a core requirement for ensuring system performance in RF substrate molding design. The industry commonly employs methods such as integrating embedded passive components (IPDs) within the packaging substrate or mounting discrete passive components on the substrate surface to construct a matching network with the gold wire inductance to compensate for impedance mismatch.

[0003] The existing closest technical solutions exhibit increasingly prominent inherent defects in high-performance RF applications: severely insufficient matching freedom and precision. Adjustable variables are limited to gold wire inductors. However, the adjustment range of gold wire inductors is constrained by the height of the molding cavity, the stability of the bonding process (such as curvature consistency and collapse degree), making continuous and precise quantitative control of their values ​​difficult. Simultaneously, the inductance values ​​of the internal metal traces on the substrate, a crucial component of the signal path, are treated as fixed parasitic parameters in existing solutions and are not included in the adjustable design scope. This single, coarse tuning method cannot meet the stringent impedance matching precision requirements of modern multi-band, high-performance RF chips. Furthermore, the inherent advantages of organic substrates are not fully utilized. One of the core advantages of organic packaging substrates lies in their ability to achieve high-precision, highly complex multi-layer wiring through photolithography and etching processes. The inductance values ​​of their internal metal traces can be controlled with extreme precision and stability by designing their length, width, spacing, shape, and even stack-up structure, with batch production dispersion far less than that of bonding wires. This results in a significant waste of substrate wiring design capabilities, limiting further exploration of the performance potential of molding packages. Poor versatility diminishes mass production cost advantages: Due to limited matching capabilities, existing solutions typically require custom-designed packaging substrates for RF chips with different impedance characteristics or operating frequency bands, including pad locations and trace layouts. This results in non-reusable substrate designs and high mold development costs, severely undermining the large-scale, low-cost mass production advantages that molding processes should possess, significantly reducing their economic viability. Summary of the Invention

[0004] The present invention aims to solve the problems of limited freedom of matching of existing radio frequency substrate molding, underutilization of substrate wiring resources, poor versatility and poor massage effect.

[0005] To address the aforementioned issues, this invention provides a multi-option cooperative matching structure for RF substrate molding, comprising an organic packaging substrate and an RF chip; the RF chip is mounted on the organic packaging substrate, and bonding wires connect the pins of the organic packaging substrate and the RF chip; passive matching elements are integrated inside or on the surface of the organic packaging substrate; the organic packaging substrate has multiple candidate bonding pads, and at least two physically separate candidate bonding pads are correspondingly configured for each pin of the RF chip; each candidate bonding pad is connected to a signal network node or passive matching element via a built-in metal trace on the organic packaging substrate; the inherent inductance values ​​of the metal traces connecting different candidate bonding pads corresponding to the same pin are different; one end of the bonding wire is connected to a pin of the RF chip, and the other end of the bonding wire is connected to a candidate bonding pad on the organic packaging substrate.

[0006] The present invention provides a multi-option cooperative matching structure and design method for RF substrate molding, which, compared with the prior art, has the following beneficial effects, but is not limited to: The organic packaging substrate of this invention serves as the core carrier for packaging. The multilayer wiring capability of the organic substrate enables a three-dimensional layout of traces, further enhancing the flexibility of inductor design. The RF chip is mounted on a predetermined chip area of ​​the organic packaging substrate using die adhesive. Its input / output pins are electrically connected to candidate bonding pads via bonding wires. The mounting gap between the chip and the substrate meets the bonding process requirements. The bonding wires provide bonding wire inductance, which is connected in series with the substrate's built-in trace inductance corresponding to the selected pad, forming the total series inductance of the signal path. Based on the size limitations of the molding compound, the accuracy of inductor adjustment and bonding reliability are ensured.

[0007] This invention represents a significant leap in matching accuracy and flexibility. Leveraging the high-density wiring capabilities of organic substrates, it achieves a two-stage adjustable mechanism: continuous fine-tuning via bonding wire tuning and discrete coarse-tuning via substrate-embedded inductor selection. The matching variable transforms from a single continuous type to a combination of discrete and continuous types, multiplying the design freedom. It allows for both coarse-tuning by selecting different trace inductors and fine-tuning by adjusting gold wire parameters, precisely adapting to complex impedance requirements, and is particularly suitable for mid-to-high frequency radio frequency scenarios.

[0008] This invention offers high predictability and consistency in performance. The inductance of the embedded traces on the substrate is ensured by the photolithography and etching process of the organic substrate, resulting in stable and discrete inductance values. This avoids the impact of process fluctuations caused by simply relying on the adjustment of gold wire length. At the same time, the protective effect of the encapsulant on the internal structure further reduces the impact of environmental factors on the stability of the inductor, significantly improving the consistency of product performance during mass production.

[0009] This invention boasts exceptional versatility and a significant cost advantage. By selecting different bonding pads, the same organic packaging substrate can cover a wider range of chip impedance or operating frequency bands, significantly improving substrate reuse. It eliminates the need for custom-designed substrates for different chips, reducing design cycles and mold investment, fully leveraging the low mass production cost advantage of molding compounding, and lowering overall packaging costs.

[0010] This invention is adapted to high-density molding compound designs: by integrating the key series inductor components inside the substrate, it reduces external space occupation, allows for the use of shorter bonding wires, reduces inductance change rate, and improves stability. It is also compatible with multilayer wiring designs for organic substrates. It enables high-density molding compounds with smaller dimensions and higher frequencies, such as microwave to millimeter-wave low-end frequency bands, optimizing RF signal transmission performance and expanding the application scenarios of substrate molding compounds.

[0011] This invention has good process compatibility and is easy to mass-produce. The pad layout and wiring design are fully compatible with the existing substrate molding bonding, mounting and molding processes. No special equipment or process steps need to be introduced. Mass production can be achieved directly based on existing production lines, which reduces the cost of technology transfer.

[0012] Furthermore, the RF chip has input pins and output pins; the candidate bonding pads connected to the input pins are input candidate bonding pads, and the built-in traces corresponding to the input candidate bonding pads are input path traces; the candidate bonding pads connected to the output pins are output candidate bonding pads, and the built-in traces corresponding to the output candidate bonding pads are output path traces.

[0013] Furthermore, the passive matching element is a capacitor or inductor connected in parallel. The passive matching element, together with the total series inductance of the input path trace and the total series inductance of the output path trace, constitutes a π-type or T-type impedance matching network.

[0014] Furthermore, at least one parameter of the length, width, line spacing, planar shape, or stacked structure of the built-in metal traces on the organic packaging substrate is set to be different; wherein, the planar shape includes one or a combination of straight lines, broken lines, and spiral lines.

[0015] Furthermore, the bonding wire is a gold wire, a copper wire, or a silver wire.

[0016] Furthermore, the organic packaging substrate is provided with an radio frequency chip.

[0017] Furthermore, the organic packaging substrate and the radio frequency chip are encapsulated in a plastic encapsulant, and the organic packaging substrate is provided with external interconnect terminals, which are solder ball arrays or pin grid arrays.

[0018] A design method for a multi-option cooperative matching structure for RF substrate molding, the specific steps of which are as follows: S1. Substrate Design and Model Building: Based on the target impedance and frequency band requirements, design the organic packaging substrate, plan at least two candidate bonding pads for each RF chip pin, and design a substrate-embedded metal trace with a specific inductance value for each candidate bonding pad; build a package electrical model that includes all candidate trace inductance options, adjustable range of bonding line inductance, passive component parameter range, and high-frequency characteristic parameters of the substrate and molding compound. S2. Multivariate Collaborative Optimization: Based on the package electrical model in step S1, candidate bonding pad selection, bonding line parameters, and passive component parameters are used as collaborative optimization variables. RF circuit simulation tools are used to traverse and simulate parameter combinations. With the system target impedance and RF performance indicators as optimization targets, the optimal parameter combination scheme is selected. S3. Bonding scheme execution and packaging manufacturing: Based on the optimal parameter combination scheme in step S2, the RF chip is mounted on the manufactured organic packaging substrate, and each pin of the RF chip is connected to the candidate bonding pad specified in the scheme through bonding wires; then molding and external interconnection are performed to complete the packaging.

[0019] Furthermore, in step S1, the geometric parameters of the built-in metal traces of each segment of the machine package substrate 2 are designed and determined using electromagnetic simulation tools, so that the inductance value forms a discrete option set with a preset step.

[0020] Furthermore, the optimization objectives of step S2 include achieving a specified voltage standing wave ratio and insertion loss within the operating frequency band; the optimal parameter combination scheme includes the candidate pad identifiers to be bonded to each pin of the RF chip, the target size parameters of the bonding wires, and the specification parameters of the passive components. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a multi-option cooperative matching structure for RF substrate molding according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a matching network circuit for a multi-option cooperative matching structure of an RF substrate encapsulation according to an embodiment of the present invention. Figure 3 This is a top view of a multi-option cooperative matching structure substrate for radio frequency substrate molding according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Test board; 2. Organic packaging substrate; 3. Surface mount inductor; 4. Bonding wire; 5. RF chip. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings showing multiple embodiments according to this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0024] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," etc., in the description, claims, and accompanying drawings of this application are open-ended terms. Therefore, "comprising," "including," or "having" refers to, for example, a method or apparatus having one or more steps or elements, but is not limited to having only these one or more elements. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] It should be emphasized that when the term "comprising / including" is used in this specification, it is used to explicitly indicate the presence of the stated feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, parts, or groups of features, integers, steps, or parts.

[0028] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0029] See Figures 1-3 An embodiment of the present invention discloses a multi-option cooperative matching structure for RF substrate molding, comprising an organic packaging substrate 2 and an RF chip 5; the RF chip 5 is mounted on the organic packaging substrate 2, and a bonding wire 4 is provided between the pins of the organic packaging substrate 2 and the RF chip 5; a passive matching element is integrated inside or on the surface of the organic packaging substrate 2; the organic packaging substrate 2 is provided with a plurality of candidate bonding pads, and the pins of the RF chip 5 are corresponding to at least two physically separate candidate bonding pads; each candidate bonding pad is connected to a signal network node or a passive matching element through a built-in metal trace on the organic packaging substrate 2; the inherent inductance values ​​of the metal traces connecting different candidate bonding pads corresponding to the same pin are different; one end of the bonding wire 4 is connected to a pin of the RF chip 5, and the other end of the bonding wire 4 is connected to a candidate bonding pad on the organic packaging substrate 2.

[0030] The organic packaging substrate 2 of the present invention serves as the core carrier for packaging. It adopts high-frequency adaptable organic substrates such as FR4 and BT resin. The multi-layer wiring capability of the organic substrate can realize the three-dimensional layout of the wiring, further improving the flexibility of inductor design.

[0031] The radio frequency chip 5 of the present invention is mounted on a preset chip area of ​​an organic packaging substrate using adhesive. Its input / output pins are electrically connected to candidate bonding pads via bonding wires. The mounting gap between the chip and the substrate meets the bonding process requirements.

[0032] The bonding wire 4 of the present invention provides a bonding wire inductance, which is connected in series with the substrate built-in trace inductance corresponding to the selected pad to form the total series inductance of the signal path; due to the size limitation of the molding compound, the length of the bonding wire 4 is controlled within the range of 0.8-2mm to ensure the accuracy of inductance adjustment and bonding reliability.

[0033] The present invention connects a chip pin to one selected from at least two candidate bonding pads, such that the total series inductance of the signal path is formed by the inductance of the bonding line and the inductance of the substrate-embedded metal trace corresponding to the selected candidate bonding pad in series.

[0034] This invention represents a significant leap in matching accuracy and flexibility. Leveraging the high-density wiring capabilities of organic substrates, it achieves a two-stage adjustable mechanism: continuous fine-tuning via bonding wire tuning and discrete coarse-tuning via substrate-embedded inductor selection. The matching variable transforms from a single continuous type to a combination of discrete and continuous types, multiplying the design freedom. It allows for both coarse-tuning by selecting different trace inductors and fine-tuning by adjusting gold wire parameters, precisely adapting to complex impedance requirements, and is particularly suitable for mid-to-high frequency radio frequency scenarios.

[0035] This invention offers high predictability and consistency in performance. The inductance of the embedded traces on the substrate is ensured by the photolithography and etching process of the organic substrate, resulting in stable and discrete inductance values. This avoids the impact of process fluctuations caused by simply relying on the adjustment of gold wire length. At the same time, the protective effect of the encapsulant on the internal structure further reduces the impact of environmental factors on the stability of the inductor, significantly improving the consistency of product performance during mass production.

[0036] This invention boasts exceptional versatility and a significant cost advantage. By selecting different bonding pads, the same organic packaging substrate can cover a wider range of chip impedance or operating frequency bands, significantly improving substrate reuse. It eliminates the need for custom-designed substrates for different chips, reducing design cycles and mold investment, fully leveraging the low mass production cost advantage of molding compounding, and lowering overall packaging costs.

[0037] This invention is adapted to high-density molding compound designs: by integrating the key series inductor components inside the substrate, it reduces external space occupation, allows for the use of shorter bonding wires, reduces inductance change rate, and improves stability. It is also compatible with multilayer wiring designs for organic substrates. It enables high-density molding compounds with smaller dimensions and higher frequencies, such as microwave to millimeter-wave low-end frequency bands, optimizing RF signal transmission performance and expanding the application scenarios of substrate molding compounds.

[0038] This invention has good process compatibility and is easy to mass-produce. The pad layout and wiring design are fully compatible with the existing substrate molding bonding, mounting and molding processes. No special equipment or process steps need to be introduced. Mass production can be achieved directly based on existing production lines, which reduces the cost of technology transfer.

[0039] Furthermore, the RF chip 5 has input pins and output pins; the candidate bonding pads connected to the input pins are input candidate bonding pads, and the built-in traces corresponding to the input candidate bonding pads are input path traces; the candidate bonding pads connected to the output pins are output candidate bonding pads, and the built-in traces corresponding to the output candidate bonding pads are output path traces.

[0040] This invention leverages the inherently different designs of the input / output terminals of radio frequency circuits, and provides a robust physical and logical framework for efficient optimization algorithms, modular design, flexible adaptation, and convenient testing. This limitation ensures that the technical solution of this invention is not only innovative in principle, but also possesses strong operability and significant performance advantages in engineering practice.

[0041] Furthermore, the passive matching element is a capacitor or inductor connected in parallel. The passive matching element, together with the total series inductance of the input path trace and the total series inductance of the output path trace, constitutes a π-type or T-type impedance matching network.

[0042] Limiting passive matching components to parallel capacitors or inductors and specifying that they, together with the series inductors of the input / output paths, form a π-type or T-type network is not an arbitrary circuit choice, but a necessary design to achieve the highest matching efficiency, the best performance trade-off, and the optimal process compatibility within a limited plastic package space.

[0043] Furthermore, at least one parameter of the length, width, line spacing, planar shape, or stacked structure of the 2 built-in metal traces on the organic packaging substrate is set to be different; wherein, the planar shape includes one or a combination of straight lines, broken lines, and spiral lines.

[0044] Different intrinsic inductance values ​​can be set by changing at least one of the parameters: length, width, line spacing, planar shape, or stacked structure.

[0045] Each output candidate bonding pad is connected to an external interconnect ball via a specially designed metal trace. The metal traces corresponding to different candidate bonding pads along the same signal path are designed with different lengths, widths, spacings, or shapes to have different inherent inductance values. The trace design fully utilizes the etching precision of the organic substrate to ensure accurate and controllable inductance values.

[0046] Furthermore, the bonding wire 4 is a gold wire, copper wire, or silver wire.

[0047] By using gold, copper, or silver bonding wires and substrate-embedded traces as synergistically adjustable dual variables, the inherent defects of single gold wire tuning are resolved, ensuring additional process flexibility, cost control, and performance optimization potential.

[0048] Furthermore, the organic packaging substrate 2 is provided with a surface mount inductor 3.

[0049] This invention achieves a high Q value, i.e., a high quality factor, improves RF performance, provides precise, stable, and discrete inductor value selection, perfectly adapts to molding processes, ensures reliability and mass production, provides key design flexibility and debugging margin, and achieves a balance between high performance, manufacturability, and low cost.

[0050] Furthermore, the organic encapsulation substrate 2 and the radio frequency chip 5 are encapsulated with a plastic encapsulating agent on their entire exterior.

[0051] Low dielectric loss epoxy resin molding compound is used to encapsulate the chip, bonding wire and passive components on the substrate surface through transfer molding process, forming a dense protective structure to prevent moisture and mechanical damage.

[0052] Furthermore, the organic packaging substrate 2 is provided with external interconnect terminals, which are solder ball arrays or pin grid arrays.

[0053] External interconnect solder balls in BGA form are set on the bottom of the organic package substrate, and the array layout is adapted to the surface mount process to realize the electrical connection between the package and the external circuit.

[0054] A design method for a multi-option cooperative matching structure for RF substrate molding, the specific steps of which are as follows: S1. Substrate Design and Model Establishment: Based on the target impedance and frequency band requirements, design the organic packaging substrate, plan at least two candidate bonding pads for each RF chip 5 pin, and design a substrate-embedded metal trace with a specific inductance value for each candidate bonding pad; establish a package electrical model that includes all candidate trace inductance options, adjustable range of bonding line inductance, passive component parameter range, and high-frequency characteristic parameters of the substrate and molding compound. S2. Multivariate Collaborative Optimization: Based on the package electrical model in step S1, candidate bonding pad selection, bonding line parameters, and passive component parameters are used as collaborative optimization variables. RF circuit simulation tools are used to traverse and simulate parameter combinations. With the system target impedance and RF performance indicators as optimization targets, the optimal parameter combination scheme is selected. S3. Bonding scheme execution and packaging manufacturing: According to the optimal parameter combination scheme in step S2, the RF chip 3 is mounted on the manufactured organic packaging substrate 2, and each pin of the RF chip 5 is connected to the candidate bonding pad specified in the scheme through bonding wires; then molding and external interconnection are performed to complete the packaging.

[0055] In step S3, for the same type of organic packaging substrate, when it is necessary to adapt to another RF chip with different impedance characteristics, step S2 is re-executed to generate an optimal parameter combination scheme for the other chip, and the new scheme is executed in the bonding stage without redesigning or manufacturing the organic packaging substrate.

[0056] The substrate design stage of this invention includes: ① Defining the impedance range, operating frequency band (e.g., 1-10GHz), and molded package size limitations of the target chip; ② Designing multiple sets of internal metal trace patterns with different inductance values ​​based on the preset matching range and the wiring rules of the organic substrate (e.g., minimum line width 0.1mm, minimum line spacing 0.1mm); ③ Terminating each set of traces to the corresponding candidate bonding pads to ensure that the difference in inductance value of traces corresponding to different pads under the same signal path is ≥0.1nH to meet the fine tuning requirements; ④ Determining the integration method based on the type of passive component. If it is embedded, a position is reserved between substrate layers; if it is surface mount, pads are designed on the surface, and the connection method between them and the traces is defined. The difference in trace inductance can be achieved in the following ways: ① Change the trace length. The longer the trace, the greater the inductance. For example, a 1mm straight trace corresponds to an inductance of about 0.3nH. ② Change the trace width. The narrower the trace width, the greater the inductance. For example, a 0.1mm trace width has about 20% higher inductance than a 0.2mm trace width. ③ Change the trace spacing. For multiple parallel traces, the smaller the spacing, the greater the coupling inductance. ④ Use different shaped trace patterns, such as straight wires, spiral wires, and zigzag wires. Spiral wires can achieve high inductance values ​​in a limited space.

[0057] The model building stage of this invention involves establishing a complete electrical model of the package structure. The model must incorporate the dielectric properties of the organic substrate, such as the dielectric constant εr = 3.8-4.5, and the high-frequency loss parameters of the molding compound, such as the loss tangent tanδ ≤ 0.005 at 10GHz. Specifically, this includes: ① different internal trace inductance options corresponding to each candidate bonding pad; ② adjustable range of bonding wire inductance, based on the variation of bonding wire length (0.8-2mm) and diameter (25-50μm), such as approximately 0.5nH inductance per mm of 25μm diameter gold wire; ③ adjustable range of integrated passive component parameters; ④ parasitic parameters of the package, such as pad parasitic capacitance and trace parasitic resistance. This ensures that the model accurately reflects the electrical characteristics of the actual substrate molding.

[0058] Simulation analysis and optimization verification of this invention: 1. Simulation Objective: Taking the system target impedance, such as the standard impedance of 50Ω, as the core optimization direction, verify the effect of the two-variable combination of "in-slab built-in trace inductance + gold wire inductance" on impedance matching, and screen the optimal parameter combination that meets the RF performance indicators, such as VSWR≤1.2 and insertion lossIL≤0.5dB.

[0059] 2. Simulation Input Parameters: Based on the electrical model of the package structure, the key input parameters include: ① Substrate parameters: dielectric constant of organic substrate εr=3.8-4.5, loss tangent tanδ≤0.005@10GHz; ② Molding material parameters such as dielectric constant and high-frequency loss characteristics; ③ Inductance options for candidate pads and corresponding traces; ④ Adjustable range of gold wire inductors; ⑤ Parameter range of integrated passive components; ⑥ Package parasitic parameters such as pad parasitic capacitance and trace parasitic resistance.

[0060] 3. Simulation Core Process: ① Variable Library Construction: Incorporate bonding pad selection, gold wire bonding parameters, and passive component parameters into a unified variable library; ② Parameter Combination Traversal: Use RF circuit simulation tools to perform co-simulation on all parameter combinations in the variable library, simulating signal transmission characteristics under different combinations; ③ Performance Index Analysis: Focus on monitoring core indicators such as VSWR, insertion loss, and isolation, and mark parameter combinations that meet design requirements; ④ Optimal Solution Screening: From qualified combinations, consider mass production process compatibility, such as the difficulty of gold wire bonding and the convenience of component procurement, to determine the final optimal parameter combination, including input / output candidate pad numbers, gold wire size parameters, and passive component specifications.

[0061] 4. Simulation output results: ① Optimal parameter combination list, clearly defining the selected pads, gold wires, and component parameters; ② Performance comparison report: including VSWR-frequency curves and insertion loss-frequency curves of this scheme and existing single-pad schemes, intuitively demonstrating the performance advantages of dual-variable adjustment; ③ Simulation conclusions: illustrating the impedance matching accuracy and stability of the optimal combination in the target frequency band, providing direct technical basis for subsequent bonding processes.

[0062] 5. Value of simulation verification: Simulation can avoid parameter matching conflicts in advance and reduce the number of physical sample trials; the output performance comparison data can be directly used as evidence of the technical superiority of this solution.

[0063] The packaging manufacturing and bonding scheme of this invention is implemented in the following stages: ① Substrate fabrication: The organic packaging substrate is manufactured according to the design, including lamination, drilling, electroplating, etching, and passive component embedding / mounting; ② Chip mounting: The RF chip is mounted on the chip area of ​​the substrate using conductive or insulating adhesive, and then cured; ③ Bonding execution: According to the optimal parameter combination determined by the simulation file, each input / output pin of the chip is bonded to the designated candidate pad according to the defined bonding scheme, and the total series inductance of the signal path is determined at one time; ④ Molding: Using transfer molding process, epoxy resin molding compound is injected into the mold to encapsulate the chip, gold wire, and passive components. The curing temperature is 150-180℃, and the curing time is 60-120s, ensuring that the molding compound is free of bubbles and cracks; ⑤ External interconnect fabrication: A solder ball array is fabricated on the bottom of the substrate, and the solder ball placement and reflow are completed to form a complete package.

[0064] The performance testing and verification stage of this invention involves: performing radio frequency performance testing on the finished package, measuring indicators such as VSWR, insertion loss, and isolation using a network analyzer to verify whether it meets the design requirements; if it needs to be adapted to a new chip, only the selected candidate pads need to be replaced during the bonding stage, without having to re-fabricate the substrate, thus achieving rapid adaptation.

[0065] Furthermore, in step S1, the geometric parameters of the built-in metal traces of each segment of the machine package substrate 2 are designed and determined using electromagnetic simulation tools, so that the inductance value forms a discrete option set with a preset step.

[0066] Transforming "continuous physical possibilities" into "controllable, discrete engineering options" lays a quantitative foundation for system-level collaborative optimization, enabling a leap from "intuitive cognition" to "precise design," creating a systematic "inductance value menu," defining tuning capability boundaries, and providing an efficient search space for subsequent "multivariate collaborative optimization," i.e., step S2.

[0067] Furthermore, the optimization objectives of step S2 include achieving a specified voltage standing wave ratio and insertion loss within the operating frequency band; the optimal parameter combination scheme includes the candidate pad identifiers to be bonded to each pin of the RF chip 5, the target size parameters of the bonding wires, and the specification parameters of the passive components.

[0068] The key to realizing the "engineering closed loop" of this invention lies in optimizing VSWR and IL as the optimization targets and outputting the optimal combination of specific production parameters. Its function is to seamlessly transform the mathematically optimal solution into executable and verifiable manufacturing commands.

[0069] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A multi-option cooperative matching structure for RF substrate molding, characterized in that, The package includes an organic packaging substrate (2) and an RF chip (5); the RF chip (5) is mounted on the organic packaging substrate (2), and a bonding wire (4) is provided between the pins of the organic packaging substrate (2) and the RF chip (5). A passive matching element is integrated inside or on the surface of the organic packaging substrate (2); multiple candidate bonding pads are provided on the organic packaging substrate (2), and the pins of the RF chip (5) are corresponding to at least two physically separate candidate bonding pads; each candidate bonding pad is connected to a signal network node or a passive matching element through a built-in metal trace on the organic packaging substrate (2); the inherent inductance values ​​of the metal traces connecting different candidate bonding pads corresponding to the same pin are different; one end of the bonding wire (4) is connected to the pin of the RF chip (5), and the other end of the bonding wire (4) is connected to a candidate bonding pad on the organic packaging substrate (2).

2. The multi-option cooperative matching structure for RF substrate molding according to claim 1, characterized in that, The RF chip (5) has input pins and output pins; the candidate bonding pads connected to the input pins are input candidate bonding pads, and the built-in traces corresponding to the input candidate bonding pads are input path traces. The candidate bonding pads that connect to the output pins are called output candidate bonding pads, and the built-in traces corresponding to the output candidate bonding pads are called output path traces.

3. The multi-option cooperative matching structure for RF substrate molding according to claim 2, characterized in that, The passive matching element is a capacitor or inductor connected in parallel. The passive matching element, together with the total series inductance of the input path trace and the total series inductance of the output path trace, constitutes a π-type or T-type impedance matching network.

4. The multi-option cooperative matching structure for RF substrate molding according to claim 3, characterized in that, The length, width, line spacing, planar shape, or stacked structure of the built-in metal traces on the organic packaging substrate (2) are set to be different; wherein, the planar shape includes one or a combination of straight lines, broken lines, and spiral lines.

5. The multi-option cooperative matching structure for RF substrate molding according to claim 4, characterized in that, The bonding wire (4) is a gold wire, a copper wire, or a silver wire.

6. The multi-option cooperative matching structure for RF substrate molding according to claim 5, characterized in that, The organic packaging substrate (2) is provided with a radio frequency chip (3).

7. The multi-option cooperative matching structure for RF substrate molding according to claim 6, characterized in that, The organic packaging substrate (2) and the radio frequency chip (5) are encapsulated with a plastic encapsulant. The organic packaging substrate (2) is provided with external interconnect terminals, which are solder ball arrays or pin grid arrays.

8. The design method of a multi-option cooperative matching structure for RF substrate molding as described in any one of claims 1-7, characterized in that, The specific steps are as follows: S1. Substrate design and model establishment: Based on the target impedance and frequency band requirements, design an organic packaging substrate, plan at least two candidate bonding pads for each RF chip (5) pin, and design a substrate built-in metal trace with a specific inductance value for each candidate bonding pad. Establish a package electrical model that includes all candidate trace inductance options, bond wire inductance adjustable range, passive component parameter range, and high-frequency characteristic parameters of the substrate and molding compound. S2. Multivariate Collaborative Optimization: Based on the package electrical model in step S1, candidate bonding pad selection, bonding line parameters, and passive component parameters are used as collaborative optimization variables. RF circuit simulation tools are used to traverse and simulate parameter combinations. With the system target impedance and RF performance indicators as optimization targets, the optimal parameter combination scheme is selected. S3. Bonding scheme execution and packaging manufacturing: According to the optimal parameter combination scheme in step S2, the radio frequency chip (3) is mounted on the manufactured organic packaging substrate (2), and each pin of the radio frequency chip (5) is connected to the candidate bonding pad specified in the scheme through bonding wire; then molding and external interconnection are carried out to complete the packaging.

9. The design method of a multi-option cooperative matching structure for RF substrate molding according to claim 8, characterized in that, In step S1, the geometric parameters of the built-in metal traces of each segment of the machine package substrate (2) are designed and determined by electromagnetic simulation tools, so that the inductance value forms a discrete option set with a preset step.

10. The design method of a multi-option cooperative matching structure for RF substrate molding according to claim 9, characterized in that, The optimization objectives of step S2 include achieving the specified voltage standing wave ratio and insertion loss within the operating frequency band; the optimal parameter combination scheme includes the candidate pad identifiers to be bonded to each pin of the RF chip (5), the target size parameters of the bonding wires, and the specification parameters of the passive components.

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