Radio frequency module and method of manufacturing the same

Abstract

The application relates to the field of wireless communication technology and provides a radio frequency module and a preparation method thereof.The radio frequency module comprises a substrate layer, first and second surface mount substrates, a first functional device, a second functional device, a third functional device and a packaging shell;the inner layer of the multilayer substrate layer is integrated with a first inner layer trace;the inner layer of the plurality of first surface mount substrates is integrated with a second inner layer trace and a first embedded inductor;the first functional device and the first embedded inductor are electrically connected with the second inner layer trace respectively;the inner layer of the plurality of second surface mount substrates is integrated with a third inner layer trace and a second embedded inductor;the layer number and thickness of the first surface mount substrate are smaller than those of the second surface mount substrate;the thickness of the first functional device is greater than that of the second functional device, and the thickness of the third functional device is greater than that of the first functional device.The radio frequency module can save the third functional device, surface layer layout and inner layer trace space.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a radio frequency module and its manufacturing method. Background Technology

[0002] Current surface mount technology (SMT) generally employs a planar mounting scheme, where all components are mounted on the same plane of the conventional substrate of the RF module. However, there are significant differences in the height of various components within the module: high-inductance components are relatively tall, while filters, low-inductance, and low-capacitance components are relatively short; even among small-package (Surface Mounted Devices, SMD) inductors, the height difference between different models and manufacturers can exceed 100μm. Due to the limitations of the module packaging structure, the final package height of the module is determined by the tallest component (such as the high-inductance component), which results in a large amount of unused empty space within the module above low-profile components such as filters, low-inductance, and low-capacitance components (e.g., ...). Figure 1 As shown, a common RF module includes a conventional substrate 01, with high-inductance components 02, a filter 03, low-inductance components 04, and low-capacitance components 05 soldered onto the upper surface of the conventional substrate 01, and is packaged through a module packaging shell 06. The conventional substrate 01 contains inner layer traces 07 and embedded inductors 08. These inner layer traces 07 are segmented, and the embedded inductors 08 are connected to the filter 03. The low-inductance components 04 and 05 are connected to other inner layer traces 07, resulting in extremely low internal space utilization within the module, severely restricting the miniaturization and thinning of the module.

[0003] To save surface area on conventional substrates for modules, existing technologies often employ embedded inductors within the substrate's inner layers, trading internal substrate space for surface layout space and reducing the use of surface SMD inductors. However, this approach has significant drawbacks: embedded inductors occupy a large amount of space within the substrate's inner layers, severely limiting routing space as traces must avoid them, significantly increasing wiring difficulty. Furthermore, it affects the substrate's electromagnetic compatibility and structural reliability, increasing the complexity of substrate design and manufacturing.

[0004] Furthermore, some surface-layer RF structures have strict requirements on the placement of inductors and capacitors. A typical example is the LC parallel resonant network, which usually requires the inductor and capacitor to be placed close together, and their relative positions must be strictly fixed. If the relative positions change, the inductor and capacitor values ​​need to be readjusted, significantly increasing the development cycle and cost. In existing technologies, LC parallel resonant networks are mostly composed of two independent SMD devices. Due to the fixed relative positions, their layout flexibility is severely limited, making it difficult to adapt to the compact module layout requirements, further restricting the improvement of module integration.

[0005] Therefore, the existing SMT packaging structure of RF modules has core problems such as low space utilization, limited substrate wiring, and poor RF layout flexibility, which cannot meet the current development requirements of communication equipment for miniaturization, high integration, and high reliability of RF modules. There is an urgent need for a new RF module packaging structure and process to solve the above technical pain points. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention proposes a radio frequency (RF) module to solve the problems of low space utilization and limited substrate layout in existing RF modules, thereby reducing the use of conventional substrate surface SMD inductors or inner layer embedded inductors, saving surface layout space and inner layer routing space.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a radio frequency (RF) module, the RF module comprising: a multilayer substrate layer; a multilayer first surface mount substrate and a second surface mount substrate respectively welded and fixed to the upper surface of the substrate layer; a first functional device welded to the upper surface of the first surface mount substrate; a second functional device welded to the upper surface of the second surface mount substrate; a third functional device welded to the upper surface of the substrate layer; and an encapsulation housing that simultaneously encloses the first surface mount substrate, the second surface mount substrate, the first functional device, the second functional device, and the third functional device on the upper surface of the substrate layer; wherein the first surface mount substrate and the second surface mount substrate are spaced apart from each other. The inner layer of the substrate layer integrates a first inner layer trace, and the inner layer of the first surface mount substrate integrates a second inner layer trace and a first embedded inductor. The first functional device and the first embedded inductor are respectively electrically connected to the second inner layer trace. The inner layer of the second surface mount substrate integrates a third inner layer trace and a second embedded inductor. The second functional device and the second embedded inductor are respectively electrically connected to the third inner layer trace. The number of layers and the thickness of the first surface mount substrate are both less than those of the second surface mount substrate; the thickness of the first functional device is greater than the thickness of the second functional device, and the thickness of the third functional device is greater than the thickness of the first functional device. Preferably, the first functional device is a filter device, the second functional device is a capacitor device, and the third functional device is an inductor device.

[0009] Preferably, the substrate layer comprises at least three layers, and the first inner layer trace is formed on the second layer of the substrate layer.

[0010] Preferably, the upper surfaces of the first functional device, the second functional device, and the third functional device are located on the same horizontal plane.

[0011] Preferably, the third inner layer trace is formed in the first layer of the second surface mount substrate near the substrate layer, and the second embedded inductor includes two, with the two second embedded inductors respectively connected to the opposite ends of the third inner layer trace.

[0012] Preferably, the first embedded inductor extends along the thickness direction of the first surface mount substrate, and the second embedded inductor extends along the thickness direction of the second surface mount substrate.

[0013] Preferably, the first surface mount substrate and the second surface mount substrate are soldered to the upper surface of the substrate layer using high-temperature tin solder at 250°C to 300°C.

[0014] Preferably, the first functional device is soldered to the upper surface of the first surface mount substrate at a low temperature of 170°C to 210°C; the second functional device is soldered to the upper surface of the second surface mount substrate at a low temperature of 170°C to 210°C.

[0015] Preferably, both the first surface mount substrate and the second surface mount substrate are manufactured using a surface mount process.

[0016] Secondly, embodiments of the present invention provide a method for fabricating a radio frequency module as described above, the method comprising the following steps: A multilayer stacked substrate layer is provided, and a first inner layer trace is integrated in the inner layer of the substrate layer; A first surface mount substrate and a second surface mount substrate with a multilayer structure are welded and stacked on the upper surface of the substrate layer. A first embedded inductor and a second inner layer trace are provided in the first surface mount substrate, and a second embedded inductor and a third inner layer trace are provided in the second surface mount substrate. The third functional device is soldered onto the upper surface of the substrate layer, and the first functional device and the second functional device are respectively soldered onto the upper surfaces of the first surface mount substrate and the second surface mount substrate. The radio frequency module is obtained by sealing the components by covering the substrate layer with a package housing.

[0017] Compared with related technologies, in the embodiments of the present invention, a multilayer structure of a first surface mount substrate, a second surface mount substrate, and an inductor is soldered to the upper surface of a substrate layer; a filter is soldered to the upper surface of the first surface mount substrate; a capacitor is soldered to the upper surface of the second surface mount substrate; an inductor is soldered to the upper surface of the substrate layer; and an encapsulation shell is covered and fixed to the upper surface of the substrate layer. The first surface mount substrate and the second surface mount substrate are spaced apart from each other. A first inner layer trace is integrated in the inner layer of the multilayer substrate layer; a second inner layer trace and a first embedded inductor are integrated in the inner layers of multiple first surface mount substrates; the filter and the first embedded inductor are electrically connected to the second inner layer trace, respectively. A third inner layer trace and a second embedded inductor are integrated in the inner layers of multiple second surface mount substrates; the capacitor and the second embedded inductor are electrically connected to the third inner layer trace, respectively. The upper surfaces of the inductor, filter, and capacitor are located on the same horizontal plane, which can reduce the use of conventional substrate surface SMD inductors or inner layer embedded inductors, saving surface layout space and inner layer trace space. Attached Figure Description

[0018] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and more readily understood through the detailed description following the accompanying drawings. In the drawings: Figure 1 A schematic diagram of the structure of an RF module provided for related technologies; Figure 2 This is a schematic diagram of the structure of the radio frequency module provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of different surface mount substrates assembled on the surface of the substrate layer in the radio frequency module provided in Embodiment 1 of the present invention; Figure 4 exist Figure 3 Based on this, a schematic diagram of the structure after different functional devices are assembled on the substrate layer and different surface mount substrates; Figure 5 This is a flowchart of the method for preparing the radio frequency module provided in Embodiment 2 of the present invention.

[0019] In the figure, 100 is the radio frequency module, 1 is the substrate layer, 11 is the first inner layer trace, 2 is the first surface mount substrate, 21 is the second inner layer trace, 22 is the first embedded inductor, 3 is the second surface mount substrate, 31 is the third inner layer trace, 32 is the second embedded inductor, 4 is the first functional device, 5 is the second functional device, 6 is the third functional device, and 7 is the package housing. Detailed Implementation

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 Please see Figures 2-4 As shown, this embodiment of the invention provides a radio frequency (RF) module 100, which includes: a multilayer substrate layer 1; a multilayer first surface mount substrate 2 and a second surface mount substrate 3 respectively welded and fixed to the upper surface of the substrate layer 1; a first functional device 4 welded to the upper surface of the first surface mount substrate 2; a second functional device 5 welded to the upper surface of the second surface mount substrate 3; a third functional device 6 welded to the upper surface of the substrate layer 1; and an encapsulation shell 7 that simultaneously encloses the first surface mount substrate 2, the second surface mount substrate 3, the first functional device 4, the second functional device 5, and the third functional device 6 on the upper surface of the substrate layer 1; the first surface mount substrate 2 and the second surface mount substrate 3 are spaced apart from each other. The substrate layer 1 is used to support and mount the third functional device 6, the first surface mount substrate 2, and the second surface mount substrate 3, and the encapsulation shell 7 is used to achieve sealed encapsulation of the internal devices, providing good protection.

[0024] The inner layer of the substrate layer 1 integrates a first inner layer trace 11. The inner layers of multiple first surface mount substrates 2 integrate a second inner layer trace 21 and a first embedded inductor 22. The first functional device 4 and the first embedded inductor 22 are electrically connected to the second inner layer trace 21, respectively. The inner layers of multiple second surface mount substrates 3 integrate a third inner layer trace 31 and a second embedded inductor 32. The second functional device 5 and the second embedded inductor 32 are electrically connected to the third inner layer trace 31, respectively. The number of layers and the thickness of the first surface mount substrate are both less than those of the second surface mount substrate. The thickness of the first functional device is greater than that of the second functional device, and the thickness of the third functional device is greater than that of the first functional device. The first embedded inductor 22 cooperates with the first functional device 4 to complete the impedance matching of the radio frequency signal, replacing the SMD inductor that originally needed to be mounted on the substrate layer 1, saving surface layout space. The second embedded inductor 32 and the second functional device 5 on the second surface mount substrate 3 are connected through the third inner layer trace 31 to form an LC parallel resonant network. This fixes the relative positions of the second embedded inductor 32 and the second functional device 5 within the small substrate, eliminating the need for adjustment and avoiding the routing avoidance and wiring limitations caused by embedded inductors in conventional substrates. By using the second inner layer trace 21 and the third inner layer trace 31 as the redistribution layer (RDL) of 3D packaging, the routing that originally needed to be completed in the inner layer of substrate layer 1 is transferred to the first surface mount substrate 2 and the second surface mount substrate 3. This frees up the inner layer routing space of conventional substrates, reduces routing difficulty, optimizes the RF signal transmission path, reduces signal loss, and improves high-frequency performance.

[0025] Specifically, by using a first surface mount substrate 2 and a second surface mount substrate 3 of different thicknesses / layers, low-profile devices such as the first functional device 4 and the second functional device 5 are precisely raised. The third functional device 6, which is of sufficient height, is directly mounted on the substrate layer 1. Ultimately, the upper surfaces of all devices are on the same horizontal plane, transforming the originally idle space inside the module into usable three-dimensional mounting space. Without increasing the total height of the module package, a 3D three-dimensional layout is achieved, significantly improving space utilization.

[0026] In this embodiment, the first embedded inductor 22 and the second embedded inductor 32 can be mass-produced for high-frequency applications, with corresponding first surface mount substrate 2 and second surface mount substrate 3 (such as a 01005 packaged 2-port substrate, less than 100µm thick, with an embedded inductance value of 0.2nH~1nH), thus reducing production costs. The 01005 package refers to an ultra-miniature component with a length of 0.25mm and a width of 0.125mm, a key device specification for miniaturizing high-end RF modules.

[0027] In this embodiment, the first functional device 4 is a filter device, the second functional device 5 is a capacitor device, and the third functional device 6 is an inductor device. By using this combination of device types, and considering the thickness differences among the three components in relation to the number and thickness of the corresponding surface mount substrate layers, it can be ensured that the upper surfaces of the filter device, capacitor device, and inductor device are precisely on the same horizontal plane. On the one hand, this can more efficiently save substrate surface layout space and inner layer routing space, avoiding signal interference caused by congested routing. On the other hand, the inductor device is directly soldered to substrate layer 1, the filter device cooperates with the first embedded inductor 22, and the capacitor device cooperates with the second embedded inductor 32. This optimizes the electrical connection paths of the three types of devices, reduces signal transmission loss, improves the filtering accuracy of the filter device, the energy storage stability of the capacitor device, and the accuracy of the inductance value of the inductor device, thereby improving the signal transmission performance and operational reliability of the entire RF module 100. Simultaneously, it simplifies the assembly process of the RF module 100 and improves production efficiency.

[0028] In this embodiment, the substrate layer 1 comprises at least three layers, with the first inner layer trace 11 formed on the second layer of the substrate layer 1. The first layer (surface layer) of the substrate layer 1 is entirely reserved as a surface mount area, specifically for soldering the first surface mount substrate 2, the second surface mount substrate 3, and the third functional device 6, without routing core circuit traces, thus avoiding interference between traces and mounting pads and devices. The second layer of the substrate layer 1 serves as a dedicated inner layer wiring layer, centrally routing the first inner layer trace 11, and undertaking the main signal transmission function of the RF module. The routing plan is not constrained by the surface mount layout. The third layer and below of the substrate layer 1 can serve as a ground layer, shielding layer, or auxiliary wiring layer, forming a vertical electromagnetic isolation structure with the second layer traces. At the same time, the stacking of multiple substrates can improve the overall mechanical strength, withstand the stress during high-temperature soldering, and prevent substrate warping and deformation. By incorporating the first inner layer trace 11 into the second layer, the surface layer wiring is not required, allowing it to be entirely used for mounting small surface mount substrates and RF devices. Combined with the integrated design of the small substrate, this further alleviates the problem of crowded surface layer layout and frees up surface layer mounting space. It also optimizes RF signal transmission performance, avoids space conflicts with inner layer traces, and improves substrate structure and soldering reliability.

[0029] In this embodiment, the upper surfaces of the first functional device 4, the second functional device 5, and the third functional device 6 are located on the same horizontal plane. Devices of different thicknesses can be mounted on different mounting substrates, ensuring that the upper surfaces of different devices are essentially on the same horizontal plane. This makes the upper surfaces of all devices essentially at the same height, fully utilizing the space above the originally low-profile devices without increasing the thickness of the RF module 100 package. This reduces the use of conventional substrate surface SMD inductors or inner layer embedded inductors, saving surface layout space and inner layer routing space. Simultaneously, by placing the upper surfaces of all devices on the same horizontal plane, the originally unused space within the module is transformed into usable three-dimensional mounting space, achieving a 3D layout without increasing the overall height of the module package, significantly improving space utilization.

[0030] In this embodiment, the first surface mount substrate 2 and the second surface mount substrate 3 have different numbers of layers and thicknesses. This flexibility in the number of layers and thicknesses of the first surface mount substrate 2 and the second surface mount substrate 3 allows for full utilization of the height difference between devices without increasing the package thickness.

[0031] In this embodiment, the third inner layer trace 31 is formed in the first layer of the second surface mount substrate 3 near the substrate layer 1. Two second embedded inductors 32 are connected to opposite ends of the third inner layer trace 31. By arranging the third inner layer trace 31 in the bottom inner layer of the second surface mount substrate 3 close to the substrate layer 1, and connecting the two second embedded inductors 32 to opposite ends of the trace, an integrated structure is formed with the trace. Combined with the second functional device 5 soldered to the top surface of the small substrate, a complete LC RF matching / resonance network is constituted. The trace is located in the inner layer of the small substrate closest to the soldering surface, and the signal transmission path is directly close to the electrical nodes of the main substrate. The two second embedded inductors 32 are symmetrically arranged along both ends of the trace, perpendicular to the second surface mount substrate 3, utilizing the thickness space without occupying planar area, to complete the impedance matching and resonant filtering functions required by the RF circuit.

[0032] In this embodiment, the first embedded inductor 22 extends along the thickness direction perpendicular to the first surface mount substrate 2, and the second embedded inductor 32 extends along the thickness direction perpendicular to the second surface mount substrate 3. The first embedded inductor 22 is perpendicular to the first surface mount substrate 2 and electrically connected to the second inner layer trace 21 to provide matching inductance for the first functional device 4. The two second embedded inductors 32 are perpendicular to the second surface mount substrate 3 and respectively connected to the two ends of the third inner layer trace 31. The third trace is located in the first layer of the second surface mount substrate 3 near the substrate layer 1, optimizing the connection path of the LC network.

[0033] In this embodiment, the first surface mount substrate 2 and the second surface mount substrate 3 are soldered to the upper surface of the substrate layer 1 using high-temperature tin solder at 250°C to 300°C.

[0034] In this embodiment, the first functional device 4 is soldered to the upper surface of the first surface mount substrate 2 using low-temperature solder at 170℃~210℃; the second functional device 5 is soldered to the upper surface of the second surface mount substrate 3 using low-temperature solder at 170℃~210℃. By adopting a stepped soldering logic of high-temperature soldering followed by low-temperature soldering, it is fully compatible with existing SMT processes. The first round of high-temperature soldering (250℃~300℃): high-melting-point solder is used to fix the small SMD substrate, and the solder joints are heat-resistant; the second round of low-temperature soldering (170℃~210℃): low-melting-point solder is used to solder the surface layer devices. The temperature is lower than the melting point of the high-temperature solder, ensuring that the solder joints of the small substrate do not remelt or shift, without the need for additional process protection.

[0035] Specifically, several small substrates with different numbers of layers and different thicknesses are stacked above substrate layer 1. These small substrates, serving as the first batch of SMD devices (first surface mount substrate 2 and second surface mount substrate 3), are connected to substrate layer 1 with high-temperature solder in the first round of soldering. These small SMD substrates contain inner layer traces and embedded inductors. Therefore, soldering one small SMD substrate is equivalent to soldering one or more SMD inductors. In addition, the second inner layer trace 21 and the third inner layer trace 31 can function as RDLs in 3D packaging technology. In the second round of soldering, devices such as low-capacitors and filters of different heights are soldered with low-temperature solder onto the second surface mount substrate 3 and the first surface mount substrate 2 of corresponding heights. The tallest third functional device 6 is directly soldered to substrate layer 1. After the second round of soldering, the upper surfaces of all devices are basically at the same height, making full use of the space above the originally low-profile devices without increasing the thickness of the module after packaging. Furthermore, these devices utilize the first embedded inductor 22 and the second embedded inductor 32 of the small first surface mount substrate 2 and the second surface mount substrate 3 to achieve impedance matching, thereby reducing the use of surface SMD inductors on the conventional substrate of the module and reducing the use of embedded inductors inside the conventional substrate of the module.

[0036] In this embodiment, both the first surface mount substrate 2 and the second surface mount substrate 3 are manufactured using surface mount technology (SMT). The first SMT substrate 2 and the second SMT substrate 3 are designed and manufactured entirely according to the standard surface mount device (SMD) process standards. The external dimensions, pad layout, and thickness tolerances of the first SMT substrate 2 and the second SMT substrate 3 are adapted to the nozzle, visual positioning, and placement requirements of the SMT pick-and-place machine, allowing for direct gripping and precise placement by the machine. By utilizing the same SMT process flow with conventional components such as filters, capacitors, and inductors on small substrates, no additional specialized processing equipment, tooling fixtures, or extra processes are required. This directly adapts to existing RF module production lines, significantly reducing the difficulty of process modification and production control. Relying on the high-precision placement characteristics of the SMT process, the precise placement position and high soldering flatness of the small substrate can be guaranteed, providing a reliable foundation for subsequent soldering of filters and the second functional device 5 on its top surface and achieving overall height alignment, avoiding device height deviations caused by placement offset or tilting. Therefore, small substrates can be manufactured using SMT processes just like other devices, without adding any additional process steps or processing equipment.

[0037] Example 2 like Figure 5 As shown, this embodiment of the invention provides a method for fabricating a radio frequency module as described above, the method comprising the following steps: S1. A multilayer stacked substrate layer 1 is provided, and a first inner layer trace 11 is integrated in the inner layer of the substrate layer 1. By providing the stacked substrate layer 1 and integrating the first inner layer trace 11 in the second inner layer, the main circuit wiring is completed.

[0038] S2. A first surface mount substrate 2 and a second surface mount substrate 3, with a multilayer structure, are soldered and stacked on the upper surface of the substrate layer 1. A first embedded inductor 22 and a second inner layer trace 21 are provided in the first surface mount substrate 2, and a second embedded inductor 32 and a third inner layer trace 31 are provided in the second surface mount substrate 3. The first surface mount substrate 2 and the second surface mount substrate 3 are soldered onto the substrate layer 1 using high-temperature solder at 250°C to 300°C. Simultaneously, the embedded inductor and inner layer trace are integrated within the substrate to realize the construction of a three-dimensional surface mount base layer.

[0039] S3. The third functional device 6 is soldered onto the upper surface of the substrate layer 1, and the first functional device 4 and the second functional device 5 are soldered onto the upper surfaces of the first surface mount substrate 2 and the second surface mount substrate 3, respectively. By using low-temperature solder (170℃~210℃), the third functional device 6 is soldered onto the substrate layer 1, the first functional device 4 is soldered onto the first surface mount substrate 2, and the second functional device 5 is soldered onto the second surface mount substrate 3. The substrate thickness is adjusted to make the upper surfaces of the three components flush, thus completing the functional device mounting and achieving height compensation.

[0040] S4. The components are sealed by covering the substrate layer 1 with the encapsulation shell 7, thus obtaining the radio frequency module 100. By covering the components with the encapsulation shell 7, all components are sealed, completing the module fabrication and achieving protection and final shaping.

[0041] In practice, the first surface mount substrate 2 and the second surface mount substrate 3 are first fixed by high-temperature soldering to form a three-dimensional mounting base layer. The high-temperature resistance of the high-melting-point solder ensures that subsequent low-temperature soldering will not cause remelting of the base layer solder joints. Then, surface layer devices are soldered by low-temperature soldering, fully compatible with existing SMT production lines, requiring no additional process modifications, and achieving layered three-dimensional soldering. In step S2, the first surface mount substrate 2 and the second surface mount substrate 3 are pre-customized according to the height of different devices, corresponding to their thickness / number of layers. After the devices are soldered in step S3, all device surfaces are automatically flush, eliminating the need for additional padding or grinding processes, fully utilizing the empty space within the module, and not increasing the total package thickness. During the mass production stage of the first surface mount substrate 2 and the second surface mount substrate 3, embedded inductors and inner layer traces are pre-integrated. The inductor mounting and wiring processes, which originally needed to be completed in the module SMT process, are transferred to the pre-production of the small substrate, simplifying the module SMT process, improving production efficiency, and ensuring the accuracy of inductor placement.

[0042] It should be noted that the various embodiments described above with reference to the accompanying drawings are merely illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be included within the scope of the present invention. Furthermore, unless the context otherwise requires, words appearing in the singular include those in the plural, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.

Claims

1. A radio frequency module, characterized in that, The radio frequency module includes: a multilayer substrate layer; a first surface mount substrate and a second surface mount substrate, which are respectively welded and fixed to the upper surface of the substrate layer; a first functional device welded to the upper surface of the first surface mount substrate; a second functional device welded to the upper surface of the second surface mount substrate; a third functional device welded to the upper surface of the substrate layer; and an encapsulation housing that simultaneously encloses the first surface mount substrate, the second surface mount substrate, the first functional device, the second functional device, and the third functional device on the upper surface of the substrate layer; the first surface mount substrate and the second surface mount substrate are spaced apart from each other. The inner layer of the substrate layer integrates a first inner layer trace, and the inner layer of the first surface mount substrate integrates a second inner layer trace and a first embedded inductor. The first functional device and the first embedded inductor are respectively electrically connected to the second inner layer trace. The inner layer of the second surface mount substrate integrates a third inner layer trace and a second embedded inductor. The second functional device and the second embedded inductor are respectively electrically connected to the third inner layer trace. The number of layers and the thickness of the first surface mount substrate are both less than the number of layers and the thickness of the second surface mount substrate; the thickness of the first functional device is greater than the thickness of the second functional device, and the thickness of the third functional device is greater than the thickness of the first functional device.

2. The radio frequency module as described in claim 1, characterized in that, The first functional device is a filter device, the second functional device is a capacitor device, and the third functional device is an inductor device.

3. The radio frequency module as described in claim 1, characterized in that, The substrate layer comprises at least three layers, and the first inner layer trace is formed on the second layer of the substrate layer.

4. The radio frequency module as described in claim 1, characterized in that, The upper surfaces of the first functional device, the second functional device, and the third functional device are located on the same horizontal plane.

5. The radio frequency module as described in claim 1, characterized in that, The third inner layer trace is formed in the first layer of the second surface mount substrate near the substrate layer. The second embedded inductor includes two inductors, which are respectively connected to the opposite ends of the third inner layer trace.

6. The radio frequency module as described in claim 1, characterized in that, The first embedded inductor extends along the thickness direction of the first surface mount substrate, and the second embedded inductor extends along the thickness direction of the second surface mount substrate.

7. The radio frequency module as described in claim 2, characterized in that, The first surface mount substrate and the second surface mount substrate are soldered to the upper surface of the substrate layer using high-temperature tin solder at 250°C to 300°C.

8. The radio frequency module as described in claim 7, characterized in that, The first functional device is soldered to the upper surface of the first surface mount substrate at a low temperature of 170℃~210℃; the second functional device is soldered to the upper surface of the second surface mount substrate at a low temperature of 170℃~210℃.

9. The radio frequency module as described in claim 1, characterized in that, Both the first surface mount substrate and the second surface mount substrate are manufactured using surface mount technology.

10. A method for manufacturing a radio frequency module as described in any one of claims 1-9, characterized in that, The preparation method includes the following steps: A multilayer stacked substrate layer is provided, and a first inner layer trace is integrated in the inner layer of the substrate layer; A first surface mount substrate and a second surface mount substrate with a multilayer structure are welded and stacked on the upper surface of the substrate layer. A first embedded inductor and a second inner layer trace are provided in the first surface mount substrate, and a second embedded inductor and a third inner layer trace are provided in the second surface mount substrate. The third functional device is soldered onto the upper surface of the substrate layer, and the first functional device and the second functional device are respectively soldered onto the upper surfaces of the first surface mount substrate and the second surface mount substrate. The radio frequency module is obtained by sealing the components by covering the substrate layer with a package housing.

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