Three-dimensional stacking module and preparation method thereof

Abstract

The present invention provides a three-dimensional stacking module and a preparation method thereof, the module comprising: a packaging substrate, embedded with a substrate groove and a plurality of welding grooves, the welding grooves are distributed on the edge of the substrate groove in a stepped shape, a functional circuit formed by at least two layers of circuit substrates is stacked on the substrate groove, the welding groove comprises a first soldering pad for transmitting a high-frequency signal or a low-frequency signal, the first soldering pad is bonded to the bottom layer of the circuit substrate along the stacking direction; an airtight enclosure frame, arranged on the packaging substrate and surrounding the circuit substrates except the bottom layer of the circuit substrate, at least one boss parallel to each layer of the circuit substrate is arranged on the inner side of the airtight enclosure frame, the boss and the circuit substrate are grounded and interconnected, while ensuring the radio frequency performance of the circuit substrate signal transmission, the signal isolation between the multiple layers of the circuit substrate is improved, and the module has high reliability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a three-dimensional stacking module and a preparation method thereof. Background Art

[0002] With the rapid development of the electronics industry, people's functional requirements for electronic products are becoming more and more complex, and their performance requirements are becoming higher and higher, which leads to the increase in their size, the increasing complexity of manufacturing process technology, and the continuous increase in costs. As a result, there is a demand to reduce the volume and weight of electronic products, which has prompted electronic products to develop towards multi-function, high performance, miniaturization and high integration. At present, three-dimensional stacking technology is one of the mainstream technologies for achieving high-performance, high-integration and miniaturized electronic products. It uses stacking technology or other micro-machining technologies such as interconnection to form a three-dimensional stack in the vertical direction of the circuit substrate. However, there is a problem of signal crosstalk between the vertically stacked multi-layer circuit substrates, which will affect the performance of the three-dimensional stacked integrated module, the working stability is low, and even the module cannot work normally, and the reliability is low. Therefore, it is very important to achieve electromagnetic isolation between the circuit substrates.

[0003] In the related art, the isolation between two layers of circuit substrates is mainly increased by planting BAG balls (Ball Grid Array Package) between two layers of stacked circuit substrates. The more balls are planted, the better the isolation between the circuit substrates. However, in practical applications, it is necessary to first determine the circuit layout of the circuit substrate, and then perform BAG ball planting in the remaining area of ​​the circuit substrate. When the circuit occupies a large area, the area provided for ball planting is not sufficient. Due to the insufficient number of balls, it is impossible to provide sufficient isolation for the multi-layer circuit substrate, resulting in serious signal crosstalk, which affects the circuit performance and low reliability. Therefore, how to improve the signal isolation between stacked circuit substrates is a problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a three-dimensional stacking module and a preparation method thereof to solve at least one of the above-mentioned technical problems.

[0005] In a first aspect, the present invention provides a three-dimensional stacking module, comprising: a packaging substrate, embedded with a substrate groove and a plurality of welding grooves, the welding grooves being distributed at the edge of the substrate groove in a stepped shape, a functional circuit formed by at least two layers of circuit substrates being stacked on the substrate groove, the welding groove comprising a first soldering pad for transmitting a high-frequency signal or a low-frequency signal, the first soldering pad being bonded to the bottom layer of the circuit substrate along the stacking direction; an airtight frame, arranged on the packaging substrate and surrounding the circuit substrates except the bottom layer of the circuit substrate, the inner side of the airtight frame being provided with at least one boss parallel to each layer of the circuit substrate, the boss and the grounding of the circuit substrate being interconnected.

[0006] In one embodiment of the present invention, the circuit substrate and the bosses are interconnected and grounded via shielding conductors, and the spacing between the shielding conductors is smaller than the spacing between the bosses.

[0007] In one embodiment of the present invention, a customizable interconnection support structure is provided between any two adjacent layers of the circuit substrate, the height of the interconnection support structure is greater than the height of the integrated devices between the two adjacent layers of the circuit substrate, and the interconnection support structure includes supporting solder balls and / or a dielectric substrate.

[0008] In one embodiment of the present invention, the dielectric substrate is embedded with a cavity, a metal column, and second pads are provided on both sides of the dielectric substrate. The cavity is provided with devices integrated between two adjacent layers of the circuit substrate, and the second pads on both sides of the dielectric substrate are connected by the metal column or the dielectric substrate.

[0009] In one embodiment of the present invention, the dielectric substrate is a metal dielectric, and the metal column running through the metal dielectric is covered with insulating material around it. The metal column is used to connect the second pad for transmitting signals. The second pad for transmitting signals and the second pad for grounding around it form a coaxial structure. The second pad for grounding is connected by the metal dielectric, and the second pad is covered with solder resist material around it.

[0010] In one embodiment of the present invention, the dielectric substrate is an insulating medium, and the metal column running through the insulating medium is used to connect the second pad for grounding and the second pad for transmitting signals, and the second pad for transmitting signals and the surrounding second pad for grounding form a quasi-coaxial structure.

[0011] In one embodiment of the present invention, a cover plate is further included, which cooperates with the airtight frame and is used to airtightly package the functional circuit. A connecting column is provided between the cover plate and the uppermost circuit board in the functional circuit, and the connecting column is used to isolate the various devices integrated on the uppermost circuit substrate.

[0012] In one embodiment of the present invention, the module also includes a cover plate, which cooperates with the airtight frame and is used to airtightly package the functional circuit. A connecting column is provided between the cover plate and the topmost circuit substrate in the functional circuit. The connecting column is used to isolate the devices integrated on the topmost circuit substrate. The connecting column includes an elastic conductor column and a slot arranged in an array on the inner side of the cover plate. One end of the elastic conductor column is embedded in the slot, and the other end is close to the topmost circuit substrate.

[0013] In one embodiment of the present invention, the elastic conductive pillars are arranged in different shapes on the uppermost circuit substrate to achieve any one of filtering, coupling and waveguide functions.

[0014] In a second aspect, the present invention also provides a method for preparing a three-dimensional stacked module, comprising: providing a packaging substrate, at least two layers of circuit substrates, a dielectric substrate, a metal column penetrating the dielectric substrate, and a packaging component, wherein if the dielectric substrate is a conductive medium, the metal column is covered with insulating material on all sides, and the packaging component includes an airtight frame, a cover plate, and a connecting column; determining two adjacent layers of the circuit substrate and the bottom layer of the circuit substrate along the stacking direction based on the stacking order of each layer of the circuit substrate; according to the position of the device between any two adjacent layers of the circuit substrate, a hollow cavity is provided in the dielectric substrate, and pads for grounding or signal transmission are provided on the top and bottom surfaces of the dielectric substrate, the metal column is used to connect at least a part of the pads on the top and bottom surfaces of the dielectric substrate, the dielectric substrate and the adjacent two layers of the circuit substrate correspond one to one, and the height of the dielectric substrate is greater than the height of the device; a base groove and a plurality of welding grooves are embedded in the packaging substrate, the welding grooves are distributed on the edge of the base groove in a stepped shape, the bottom layer of the circuit substrate is stacked on the base groove, and a soldering pad for grounding or signal transmission is provided in the soldering groove. The invention relates to a method for manufacturing a circuit substrate of a plurality of circuit substrates, wherein the plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding. The plurality of circuit substrates are connected to each other by bonding.

[0015] In a third aspect, the present invention also provides another method for preparing a three-dimensional stacked module, comprising: providing a packaging substrate, at least two layers of circuit substrates, supporting solder balls and a packaging component, wherein the packaging component comprises an airtight frame, a cover plate and connecting columns; determining two adjacent layers of the circuit substrates and the bottom layer of the circuit substrate along the stacking direction based on the stacking order of each layer of the circuit substrates; embedding a base groove and a plurality of welding grooves in the packaging substrate, wherein the welding grooves are distributed in a stepped manner on the edge of the base groove, stacking the bottom layer of the circuit substrate in the base groove, and providing a welding pad for high-frequency signal or low-frequency signal transmission in the welding groove, and bonding the welding pad in the welding groove to the bottom layer of the circuit substrate; after the bottom layer of the circuit substrate is stacked, using the supporting solder balls to bond the adjacent layers when each layer of the circuit substrate is stacked. The two layers of circuit substrates are interconnected, and the height of the supporting solder balls is greater than the height of the devices between the two adjacent layers of circuit substrates; an airtight frame is provided on the packaging substrate to surround the circuit substrates except the bottom layer of the circuit substrate, and at least one boss parallel to the circuit substrate is provided on the inner side of the airtight frame, and the boss and the circuit substrate are grounded to complete the stacking of one layer of the circuit substrate; until all the circuit substrates are stacked to form a functional circuit, the connecting column is fixed to the inner side of the cover plate according to the position of the device integrated by the top layer of the circuit substrate in the functional circuit, and the cover plate is fixed directly above the airtight frame to isolate the devices integrated on the top layer of the circuit substrate, complete the airtight packaging of the functional circuit, and form a three-dimensional stacking module.

[0016] Beneficial effects of the present invention: The present invention proposes a three-dimensional stacking module and a preparation method thereof, comprising: a packaging substrate, a substrate groove and a plurality of welding grooves are embedded therein, the welding grooves are distributed at the edge of the substrate groove in a stepped shape, a functional circuit formed by at least two layers of circuit substrates is stacked on the substrate groove, the welding groove includes a first pad for transmitting a high-frequency signal or a low-frequency signal, and the first pad is bonded to the bottommost circuit substrate along the stacking direction; an airtight enclosure is arranged on the packaging substrate and surrounds the circuit substrates except the bottommost circuit substrate, and the inner side of the airtight enclosure is provided with at least one boss parallel to each layer of the circuit substrate, and the boss and the circuit substrate are grounded and interconnected. In this way, first, by setting the first pad of the welding groove to connect the high-frequency and low-frequency signals with the bottommost circuit substrate, the radio frequency performance of the circuit substrate signal transmission is improved; second, by the ground connection between the boss and the circuit substrate, not only the signal isolation between the layers of the circuit substrates is improved to avoid signal crosstalk between the layers of the circuit substrates, the module has high reliability, and the working bandwidth of the three-dimensional stacking module can be increased, and the performance is higher; third, the three-dimensional stacking module is simple and easy to manufacture, with low cost and high practicality. In addition, by providing a customizable interconnection support structure between two adjacent layers of circuit substrates, high-pitch multi-layer circuit substrate stacking is achieved while ensuring signal isolation between the two layers of circuit substrates.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0019] Figure 1 is a cross-sectional view of a three-dimensional stacked module shown in an exemplary embodiment of the present invention;

[0020] Figure 2 is a cross-sectional view of a packaging substrate shown in an exemplary embodiment of the present invention;

[0021] Figure 3 is a top view of a packaging substrate shown in an exemplary embodiment of the present invention;

[0022] Figure 4 is a top view of an airtight fence shown in an exemplary embodiment of the present invention;

[0023] Figure 5is a schematic structural diagram of a circuit substrate excluding the bottom layer, shown in an exemplary embodiment of the present invention;

[0024] Figure 6 is a schematic structural diagram of the connection between a boss and a circuit substrate shown in an exemplary embodiment of the present invention;

[0025] Figure 7 is a schematic diagram of a simulation of a three-dimensional stacked module without adding a shielding conductor, shown in an exemplary embodiment of the present invention;

[0026] Figure 8 is a schematic diagram of a simulation of a three-dimensional stacked module with added shielding conductors, shown in an exemplary embodiment of the present invention;

[0027] Fig. 9 is a cross-sectional view of another three-dimensional stacked module according to an exemplary embodiment of the present invention;

[0028] Fig.10 is a schematic structural diagram of a dielectric substrate made of a metal medium shown in an exemplary embodiment of the present invention;

[0029] Fig.11 is a schematic structural diagram of a dielectric substrate made of an insulating medium shown in an exemplary embodiment of the present invention;

[0030] Fig.12 is a cross-sectional view of a connecting column shown in an exemplary embodiment of the present invention;

[0031] Fig.13 is a top view of a connecting column shown in an exemplary embodiment of the present invention;

[0032] Fig.14 is a top view of different shapes formed by conductor pillars shown in an exemplary embodiment of the present invention;

[0033] Fig.15 is a top view of a waveguide interface shown in an exemplary embodiment of the present invention;

[0034] Fig.16 is a flow chart of a method for preparing a three-dimensional stacked module shown in an exemplary embodiment of the present invention;

[0035] Fig.17 is a flow chart showing another method for preparing a three-dimensional stacked module according to an exemplary embodiment of the present invention;

[0036] Among them, 1-packaging substrate; 2-circuit substrate; 3-airtight frame; 4-device; 5-cover; 6-elastic conductor column; 7-slot; 8-shielding conductor; 9-dielectric substrate; 10-solder ball for welding the second pad; 11-base groove; 12-welding groove; 13-top surface of packaging substrate; 14-ground circuit; 15-first pad for transmitting low-frequency signal; 16-signal pad surrounded by ground circuit; 17-first pad for transmitting high-frequency signal; 18-metal layer on the top surface of packaging substrate; 19-boss; 20-support solder ball; 21-cavity; 22-metal medium; 23-second pad; 24-metal column; 25-insulating material; 26-solder resist material; 27-coaxial structure; 28-insulating medium; 29-quasi-coaxial structure; 30-arrayed slots; 31-waveguide structure coupling; 32-waveguide structure; 33-multi-stage resonant cavity structure; 34-waveguide interface. DETAILED DESCRIPTION

[0037] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0038] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0039] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0040] See also Figure 1 , is a side view of a three-dimensional stacking module shown in an exemplary embodiment of the present invention. The exemplary embodiment provides a three-dimensional stacking module, which at least includes: Figure 1The package substrate 1 shown is embedded with a base groove 11 and multiple welding grooves 12. The welding grooves 12 are distributed on the edge of the base groove 11 in a stepped shape. The base groove 11 is stacked with functional circuits formed by at least two layers of circuit substrates 2. The welding grooves 12 include a first pad for transmitting high-frequency signals or low-frequency signals. The first pad is bonded to the bottom layer of the circuit substrate along the stacking direction. The airtight frame 3 is arranged on the package substrate 1 and surrounds the circuit substrates except the bottom layer. The inner side of the airtight frame 3 is provided with at least one boss parallel to each layer of the circuit substrate. The boss and the circuit substrate are grounded and interconnected. It should be understood that Figure 1 This is a schematic diagram of stacking two layers of circuit substrates. If another layer of circuit substrate needs to be stacked, it is only necessary to continue stacking a layer of interconnection support structure and a layer of circuit substrate in the stacking direction of the circuit substrates, and add a layer of airtight frame parallel to the newly stacked circuit substrate, and so on.

[0041] In one embodiment of the present invention, taking into account the airtightness of the three-dimensional stacked module, the packaging substrate is made of an airtight material, and there is a multi-layer circuit structure inside the packaging substrate, and its top surface pad (for example, the first pad and the pad on the base groove) is connected to the bottom pad. In addition, the bottom layer of the circuit substrate in the functional circuit is bonded or welded to the packaging substrate. The packaging substrate can be compatible with functional circuits with different functions. The functional circuit is formed by stacking multiple layers of circuit substrates and integrates multiple functions, such as coupling, power divider, balun, antenna or filter functions, which can be adaptively designed according to actual application requirements. In other words, each layer of the circuit substrate can design the circuit according to actual needs and integrate the required devices, such as Figure 1 As shown, the device can be embedded in the circuit substrate or fixed on the top surface of the circuit substrate.

[0042] See also Figure 2 and Figure 3 , are respectively a cross-sectional view and a top view of a package substrate according to an exemplary embodiment of the present invention. Figure 2 and Figure 3 As shown, the package substrate 1 is embedded with a base groove 11 and a plurality of welding grooves 12 distributed on the upper edge of the base groove 11. The base groove 11 and the welding groove 12 are combined to form a Figure 2As shown in the stepped shape, a large-area grounding circuit 14 and a pad 16 for transmitting signals surrounded by the grounding circuit are arranged at the bottom of the base groove 11. The bottom circuit substrate is stacked on the substrate groove 11, which reduces the volume of the three-dimensional stacking module while making the bottom circuit substrate have a stronger grounding and signal transmission performance; and the bottom of the welding groove 12 is provided with an exposed first pad 17 for transmitting high-frequency signals and a first pad 15 for transmitting low-frequency signals, which further ensures the stable transmission of high-frequency signals and low-frequency signals of the functional circuit, and has high radio frequency performance. In addition, the top surface 13 of the packaging substrate is covered with a metal layer 18 for welding, so as to facilitate welding the airtight frame 3 to the packaging substrate, that is, the edge of the top surface of the packaging substrate, the area with the metal layer 18.

[0043] In one embodiment of the present invention, the width of the welding groove 12, that is, the length of the welding groove 12 perpendicular to the edge of the substrate groove 11, needs to be less than half of the wavelength of the working signal of the functional circuit adjacent to the welding groove 12 to ensure the performance and stability of the functional circuit. Figure 3 As shown, the width a, d, or b+c of the welding groove 12 must be greater than half of the wavelength of the working signal of the functional circuit.

[0044] See also Figures 4 to 6 , is a schematic diagram of an airtight fence and a matching circuit substrate shown in an exemplary embodiment of the present invention. Figures 4 to 6 As shown, the circuit substrate 2 (except the bottom circuit substrate) and the boss 19 are interconnected and grounded through the shielding conductor 8 to increase the signal isolation between the stacked circuit substrates 2, avoid signal crosstalk between different circuit substrates, and improve the stability and reliability of the module. The spacing between the shielding conductors 8 is smaller than the spacing between the bosses 19; the side shape of the circuit substrate 2 matches the shape of the corresponding boss, so as to avoid poor isolation due to the long spacing between the shielding conductors 8, and further improve the isolation of the circuit substrate 2.

[0045] In one embodiment of the present invention, the spacing between the plurality of bosses 19 on the inner side of the airtight enclosure 3 and parallel to each layer of the circuit substrate 2 is greater than half of the wavelength of the working signal of the adjacent functional circuit, so as to further ensure the performance and stability of the functional circuit. Figure 4 As shown, the intervals e, f+g, and h between the plurality of projections 19 need to be greater than half of the wavelength of the working signal of the adjacent functional circuit.

[0046] In one embodiment of the present invention, by adjusting the spacing between shielding conductors and the number of shielding conductors, not only the signal isolation between multi-layer circuit substrates can be improved, but also the working bandwidth and signal transmission performance of the multi-layer circuit substrate can be increased.

[0047] See also Figure 7 and Figure 8 , are schematic diagrams of simulation of a three-dimensional stacked module without and with a shield conductor, respectively, according to an exemplary embodiment of the present invention. Taking the actual simulation test as an example, a three-dimensional stacked module pair with only two layers of circuit substrates stacked is used as a simulation object, such as Figure 7 As shown in the figure, when no shielding conductor is added, the signal isolation between the top circuit substrate and the bottom circuit substrate in the 1 to 25 GHz frequency band (i.e. Figure 7 The simulation results of S(3,1) and S(4,1)) are between 40dB and 80dB, and in the frequency band of 10 to 25GHz, the signal isolation does not reach 60dB. In addition, a resonance point appears at the frequency of 26.5GHz, which affects the working bandwidth, and the signal insertion loss of the three-dimensional stacking model (i.e. Figure 7 The S(2,1) in the frequency band is better than 0.03dB, and the return loss is better than 24dB. Figure 8 As shown in the figure, when adding a shield conductor, the signal isolation between the top circuit substrate and the bottom circuit substrate in the frequency band of 1 to 40 GHz (i.e. Figure 8 The simulation results of S(3,1) and S(4,1) in the figure are all better than 93dB, which is much higher than the simulation results without adding shielded conductors, and no resonance point appears, which greatly increases the working bandwidth of the three-dimensional stacking model, and the signal insertion loss of the three-dimensional stacking model (i.e. Figure 8 The S(2,1) in the figure is better than 0.03dB within its frequency band, especially in the 1-25GHz band, the signal insertion loss is better than 0.016dB and the return loss is better than 27dB, which is still better than the three-dimensional stacked module without adding shielded conductors, improving the signal transmission performance of the circuit substrate.

[0048] In one embodiment of the present invention, the shielding conductor may be made of metal materials such as gold wire or gold tape, which is not limited herein.

[0049] Specifically, if two adjacent layers of circuit substrates are interconnected by ball planting, the height spacing between the two layers of circuit substrates will be limited by the diameter of ordinary solder balls, and high spacing stacking between the circuit substrates cannot be achieved. Therefore, a customizable interconnection support structure is provided between any two adjacent layers of circuit substrates. The height of the interconnection support structure is greater than the height of the integrated devices between the two adjacent layers of circuit substrates. The interconnection support structure includes supporting solder balls 20 and / or dielectric substrates 9. In this way, through the customizable interconnection support structure, while improving the isolation between the two adjacent layers of circuit substrates and reducing signal crosstalk, the spacing between the circuit substrates can also be controlled according to actual needs to achieve high spacing multi-layer circuit substrate stacking.

[0050] See also Fig. 9, is a cross-sectional view of another three-dimensional stacked module according to an exemplary embodiment of the present invention. Figure 1 The dielectric substrate 9 shown in the figure can also be interconnected by only using Fig. 9 The supporting solder balls 20 shown are interconnected, or the dielectric substrate 9 and the supporting solder balls 20 are combined to connect two adjacent layers of circuit substrates.

[0051] Specifically, the dielectric substrate 9 is embedded with a cavity 21, a metal column 24, and second pads 23 on both sides of the dielectric substrate 9. The device 4 integrated between two adjacent layers of circuit substrates is arranged in the cavity 21. The second pads 23 on both sides of the dielectric substrate 9 are connected by the metal column 24 or the dielectric substrate 9.

[0052] In one embodiment of the present invention, a cavity 21 is provided in the dielectric substrate 9, and the devices 4 integrated between two adjacent layers of circuit substrates are isolated by the dielectric substrate, thereby further improving the isolation between the circuit substrates and avoiding electromagnetic interference.

[0053] See also Fig.10 , is a schematic structural diagram of a dielectric substrate made of a metal medium according to an exemplary embodiment of the present invention.

[0054] like Fig.10 As shown, the dielectric substrate 9 is a metal dielectric 22, and an insulating material 25 is covered around a metal column 24 that runs through the metal dielectric 22. The metal column 24 is used to connect to a second pad 23 for transmitting signals. The second pad 23 for transmitting signals and the surrounding grounded second pad 23 form a coaxial structure 27. The grounded second pad 23 is connected by the metal dielectric 22, and the second pad 23 is covered with a solder resist material 26.

[0055] In one embodiment of the present invention, since the metal medium 22 is conductive, the connected second pads 23 located on both sides of the metal medium 22 will cause signal crosstalk between the second pads 23, and will also cause the grounded second pads 23 to short-circuit. Therefore, a solder resist material 26 is arranged around each second pad 23, and the metal column 24 used to transmit the signal is wrapped with an insulating material 25, so that the second pads 23 for transmitting signals connected by the metal column 24 can transmit signals independently, while multiple grounded signals are connected by the metal medium 22. In this way, not only the performance of signal transmission and grounding between the two layers of circuit substrates is ensured, but also the second pads 23 for transmitting signals and the surrounding grounded second pads 23 form a coaxial structure 27, which further improves the ability of radio frequency signal transmission.

[0056] See also Fig.11 , is a schematic diagram of a dielectric substrate made of an insulating medium according to an exemplary embodiment of the present invention. Fig.11As shown, the dielectric substrate 9 is an insulating medium 28, and the metal column 24 running through the insulating medium 28 is used to connect the second grounded pad 23 and the second pad 23 for transmitting signals. The second pad 23 for transmitting signals and the surrounding grounded second pad 23 form a quasi-coaxial structure 29.

[0057] In one embodiment of the present invention, the second pads 23 constituting the quasi-coaxial structure 29 are connected, that is, the metal pillars 24 included in the quasi-coaxial structure 29 are connected, so that Fig.11 For example, the number of second pads 23 on both sides of the insulating medium in the quasi-coaxial structure 29 is 14, all of which are connected, or large-sized second pads 23 are directly used on both sides of the insulating medium to cover the area where the quasi-coaxial structure is located, and the area where 29 is located is connected by 7 metal pillars 24. In this way, while the isolation of the circuit substrates on the adjacent two sides is improved through the insulating medium, the ability of the circuit substrate to transmit RF signals is ensured.

[0058] Specifically, the three-dimensional stacking module also includes a cover plate 5, which cooperates with the airtight frame 3 to hermetically seal the functional circuit. A connecting column is provided between the cover plate 5 and the uppermost circuit substrate in the functional circuit, and the connecting column is used to isolate the components 4 integrated on the uppermost circuit substrate. Under airtight conditions, the cover plate 5 is an airtight cover plate.

[0059] Through the above method, the packaging substrate, airtight frame and cover plate made of airtight materials are used to ensure the airtightness of the three-dimensional stacked module while improving the overall electromagnetic shielding capability of the three-dimensional stacked module, thereby avoiding the impact of high water vapor content inside the module on the performance, life and reliability of the module.

[0060] In one embodiment of the present invention, multiple shielding cavities can be formed between the cover plate and the uppermost circuit substrate in the functional circuit by connecting the pillars, for example Figure 1 The space on both sides of the connecting column is used to isolate the components and effectively suppress the signal crosstalk of the top circuit substrate. In addition, the frame and the airtight fence are made of metal materials with a solderable coating on the surface.

[0061] See also Fig.12 and Fig.13 , are respectively a cross-sectional view and a top view of a connection column shown in an exemplary embodiment of the present invention. The connection column comprises an elastic conductor column 6 and slots 7 arranged in an array on the inner side of the cover plate, one end of the elastic conductor column 6 is embedded in the slot 7, and the other end is close to the topmost circuit substrate.

[0062] In practical applications, the slots 7 on the inner side of the cover can be distributed and customized according to the positions of the components integrated in the topmost circuit substrate to effectively isolate the components. According to requirements, one component can be isolated separately, or multiple components can be isolated together.

[0063] In one embodiment, elastic conductor columns are formed into different shapes on the uppermost circuit substrate to achieve any one of the functions of filtering, coupling and waveguide.

[0064] See also Fig.14 , is a top view of different shapes formed by elastic conductor pillars according to an exemplary embodiment of the present invention. Fig.14 As shown, a multi-stage resonant cavity structure 33 is arranged on the uppermost circuit substrate by elastic conductor columns, and electromagnetic coupling is achieved between each resonant cavity through a wider gap. A filter structure is formed by connecting the multi-stage resonant cavities 33 in series or in parallel to achieve a filtering function; a rectangular waveguide structure 31 is formed by multiple elastic conductor columns, and a microstrip-waveguide conversion structure arranged on the uppermost circuit substrate is provided in the waveguide structure to achieve a waveguide function, so that microwave signals can be transmitted with high performance in the upper space of the functional circuit; two rectangular waveguide structures 32 are formed by elastic conductor columns, and coupling is achieved between the two waveguide structures through a gap, thereby achieving the function of a coupler.

[0065] See also Fig.15 , is a top view of a waveguide interface according to an exemplary embodiment of the present invention. Fig.15 As shown, under non-airtight conditions, a groove can be made on the cover at a position corresponding to the waveguide structure surrounded by the elastic conductor column, so that the groove 34 and the elastic conductor column can form a waveguide interface, and a radio frequency connector can be connected to the groove 34 of the cover to achieve interconnection with other modules, or the antenna can be directly connected to realize the AIP (Antenna in package) structure.

[0066] See also Fig.16 , is a flow chart of a method for preparing a three-dimensional stacked module according to an exemplary embodiment of the present invention. Fig.16 As shown, in an exemplary embodiment, the method for preparing a three-dimensional stacked module includes at least steps S1601 to S1607, which are described in detail as follows:

[0067] Step S1601, providing a packaging substrate, at least two layers of circuit substrates, a dielectric substrate, a metal column penetrating the dielectric substrate, and a packaging component, wherein if the dielectric substrate is a conductive medium, the metal column is covered with insulating material around it, and the packaging component includes an airtight frame, a cover plate, and a connecting column;

[0068] Step S1602, determining two adjacent layers of circuit substrates and the bottom layer of circuit substrates along the stacking direction based on the stacking order of each layer of circuit substrates;

[0069] Step S1603, according to the position of the device between any two adjacent layers of circuit substrates, a hollow cavity is provided in the dielectric substrate, and pads for grounding or signal transmission are provided on the top and bottom surfaces of the dielectric substrate, and at least a portion of the pads on the top and bottom surfaces of the dielectric substrate are connected by metal pillars, the dielectric substrate and the two adjacent layers of circuit substrates correspond one to one, and the height of the dielectric substrate is greater than the height of the device;

[0070] Step S1604, embedding a base groove and a plurality of welding grooves in the packaging substrate, wherein the welding grooves are distributed at the edge of the base groove in a stepped shape, stacking the bottom circuit substrate in the base groove, and arranging welding pads for high-frequency signal or low-frequency signal transmission in the welding groove, and bonding the welding pads in the welding groove to the bottom circuit substrate;

[0071] Step S1605, after the bottom layer of circuit substrates is stacked, each time a layer of circuit substrates is stacked, the devices between two adjacent layers of circuit substrates are placed in the cavities of the corresponding dielectric substrates, and the two adjacent layers of circuit substrates are interconnected using pads on the bottom and top surfaces of the dielectric substrates;

[0072] Step S1606, a layer of airtight enclosure is provided on the packaging substrate to surround the circuit substrates except the bottom circuit substrate, at least one boss parallel to the circuit substrate is provided inside the airtight enclosure, and the boss and the circuit substrate are grounded to complete the stacking of a layer of circuit substrates;

[0073] Step S1607, until all circuit substrates are stacked to form a functional circuit, the connecting pillars are fixed to the inner side of the cover according to the positions of the devices integrated in the topmost circuit substrate in the functional circuit, and the cover is fixed directly above the airtight frame to isolate the devices integrated in the topmost circuit substrate, thereby completing the airtight packaging of the functional circuit and forming a three-dimensional stacked module.

[0074] See also Fig.17 , is a flow chart of another method for preparing a three-dimensional stacked module according to an exemplary embodiment of the present invention. Fig.17 As shown, in another exemplary embodiment, the method for preparing a three-dimensional stacked module includes at least steps S1701 to S1706, which are described in detail as follows:

[0075] Step S1701, providing a packaging substrate, at least two layers of circuit substrates, supporting solder balls and packaging components, the packaging components including an airtight frame, a cover plate and connecting pillars;

[0076] Step S1702, determining two adjacent layers of circuit substrates and the bottom layer of circuit substrates along the stacking direction based on the stacking order of each layer of circuit substrates;

[0077] Step S1703, embedding a base groove and a plurality of welding grooves in the packaging substrate, wherein the welding grooves are distributed at the edge of the base groove in a stepped shape, stacking the bottom circuit substrate in the base groove, and arranging welding pads for high-frequency signal or low-frequency signal transmission in the welding groove, and bonding the welding pads in the welding groove to the bottom circuit substrate;

[0078] Step S1704, after the bottom layer of circuit substrates is stacked, when each layer of circuit substrates is stacked, two adjacent layers of circuit substrates are interconnected using supporting solder balls, and the height of the supporting solder balls is greater than the height of the devices between the two adjacent layers of circuit substrates;

[0079] Step S1705, a layer of airtight enclosure frame is provided on the packaging substrate to surround the circuit substrates except the bottom circuit substrate, at least one boss parallel to the circuit substrate is provided inside the airtight enclosure frame, and the boss and the circuit substrate are grounded to complete the stacking of a layer of circuit substrates;

[0080] Step S1706, until all circuit substrates are stacked to form a functional circuit, the connecting pillars are fixed to the inner side of the cover according to the positions of the devices integrated in the topmost circuit substrate in the functional circuit, and the cover is fixed directly above the airtight frame to isolate the devices integrated in the topmost circuit substrate, thereby completing the airtight packaging of the functional circuit and forming a three-dimensional stacked module.

[0081] The above preparation method steps are merely illustrative and are not intended to be specific limitations of the present application.

[0082] Based on the above embodiments, firstly, by providing the first soldering pad of the soldering groove to connect the signal with the bottom layer of the circuit substrate, the radio frequency capability of the circuit substrate signal transmission is improved.

[0083] Second, through the grounding connection between the boss and the circuit substrate, not only the signal isolation between the layers of circuit substrates is improved to avoid signal crosstalk between the layers of circuit substrates, the module operation reliability is high, but also the working bandwidth of the three-dimensional stacked module can be increased, and the performance is higher.

[0084] Third, the three-dimensional stacking module is simple and easy to manufacture, with low cost and high practicality.

[0085] Fourth, by setting a customizable interconnection support structure between two adjacent layers of circuit substrates, high-pitch multi-layer circuit substrate stacking is achieved while ensuring signal isolation and RF signal transmission capability between the two layers of circuit substrates.

[0086] Fifth, multiple shielding cavities are formed between the cover plate and the top circuit substrate through connecting columns to isolate the devices, effectively suppressing the signal crosstalk of the top circuit substrate and further improving the overall electromagnetic interference performance of the three-dimensional stacked module.

[0087] Sixth, the packaging substrate, airtight frame and cover made of airtight materials ensure the airtightness of the three-dimensional stacked module while improving the overall electromagnetic shielding capability of the three-dimensional stacked module, thereby avoiding the impact of high water vapor content inside the module on the performance, life and reliability of the module.

[0088] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A three-dimensional stacking module, characterized in that: include: A packaging substrate, embedded with a base groove and a plurality of welding grooves, wherein the welding grooves are distributed at the edge of the base groove in a stepped shape, a functional circuit formed by at least two layers of circuit substrates is stacked on the base groove, and the welding groove includes a first pad for transmitting a high-frequency signal or a low-frequency signal, and the first pad is bonded to the bottom layer of the circuit substrate along the stacking direction; An airtight frame is provided on the packaging substrate and surrounds the circuit substrates except the bottom circuit substrate. The inner side of the airtight frame is provided with at least one boss parallel to each layer of the circuit substrate. The boss is interconnected with the ground of the circuit substrate.

2. The three-dimensional stacking module according to claim 1, characterized in that: The circuit substrate and the bosses are interconnected and grounded via shielding conductors, and the spacing between the shielding conductors is smaller than the spacing between the bosses.

3. The three-dimensional stacking module according to claim 1, characterized in that: A customizable interconnection support structure is provided between any two adjacent layers of the circuit substrates. The height of the interconnection support structure is greater than the height of the integrated devices between the two adjacent layers of the circuit substrates. The interconnection support structure includes supporting solder balls and / or a dielectric substrate.

4. The three-dimensional stacking module according to claim 3, characterized in that: The dielectric substrate is embedded with a cavity, a metal column and second pads on both sides of the dielectric substrate. The cavity is provided with integrated devices between two adjacent layers of the circuit substrate. The second pads on both sides of the dielectric substrate are connected by the metal column or the dielectric substrate.

5. The three-dimensional stacking module according to claim 4, characterized in that: The dielectric substrate is a metal dielectric, and insulating material is covered around the metal column that runs through the metal dielectric. The metal column is used to connect the second pad that transmits the signal. The second pad that transmits the signal and the second pad that is grounded around it form a coaxial structure. The grounded second pad is connected by the metal dielectric, and the second pad is covered with solder resist material.

6. The three-dimensional stacking module according to claim 4, characterized in that: The dielectric substrate is an insulating medium. The metal column running through the insulating medium is used to connect the second grounded pad and the second signal transmission pad. The second signal transmission pad and the surrounding grounded second pad form a quasi-coaxial structure.

7. The three-dimensional stacking module according to any one of claims 1 to 6, characterized in that: It also includes a cover plate, which cooperates with the airtight frame and is used to airtightly package the functional circuit. A connecting column is provided between the cover plate and the uppermost circuit substrate in the functional circuit. The connecting column is used to isolate the components integrated on the uppermost circuit substrate. The connecting column includes an elastic conductor column and slots arranged in an array on the inner side of the cover plate. One end of the elastic conductor column is embedded in the slot, and the other end is in close contact with the uppermost circuit substrate.

8. The three-dimensional stacking module according to claim 7, characterized in that: The elastic conductor columns are formed into different shapes on the uppermost circuit substrate to realize any function of filtering, coupling and waveguide.

9. A method for preparing a three-dimensional stacked module, characterized in that: The method comprises: Providing a packaging substrate, at least two layers of circuit substrates, a dielectric substrate, a metal column penetrating the dielectric substrate, and a packaging component, wherein if the dielectric substrate is a conductive medium, the metal column is covered with insulating material around it, and the packaging component includes an airtight frame, a cover plate, and a connecting column; Determine two adjacent layers of the circuit substrates and the bottom layer of the circuit substrate along the stacking direction based on the stacking order of each layer of the circuit substrates; According to the position of the device between any two adjacent layers of circuit substrates, a hollow cavity is provided in the dielectric substrate, and pads for grounding or signal transmission are provided on the top and bottom surfaces of the dielectric substrate, and the metal pillars are used to connect at least a part of the pads on the top and bottom surfaces of the dielectric substrate, the dielectric substrate corresponds to the two adjacent layers of circuit substrates one by one, and the height of the dielectric substrate is greater than the height of the device; A base groove and a plurality of welding grooves are embedded in the packaging substrate, the welding grooves are distributed at the edge of the base groove in a stepped shape, the bottom layer of the circuit substrate is stacked on the base groove, and a welding pad for high-frequency signal or low-frequency signal transmission is arranged in the welding groove, and the welding pad in the welding groove is bonded to the bottom layer of the circuit substrate; After the bottom layer of the circuit substrate is stacked, each time a layer of the circuit substrate is stacked, the device between two adjacent layers of the circuit substrate is placed in the cavity corresponding to the dielectric substrate, and the two adjacent layers of the circuit substrate are interconnected by using the pads on the bottom and top surfaces of the dielectric substrate; A layer of the airtight enclosure frame surrounding the circuit substrates except the bottom circuit substrate is arranged on the packaging substrate, at least one boss parallel to the circuit substrate is arranged inside the airtight enclosure frame, and the boss and the circuit substrate are grounded to complete the stacking of a layer of the circuit substrate; Until all the circuit substrates are stacked to form a functional circuit, the connecting pillars are fixed to the inner side of the cover according to the positions of the devices integrated in the topmost circuit substrate in the functional circuit, and the cover is fixed directly above the airtight frame to isolate the devices integrated in the topmost circuit substrate, thereby completing the airtight packaging of the functional circuit and forming a three-dimensional stacked module.

10. A method for preparing a three-dimensional stacked module, characterized in that: The method comprises: Providing a packaging substrate, at least two layers of circuit substrates, supporting solder balls and a packaging component, wherein the packaging component includes an airtight surrounding frame, a cover plate and connecting pillars; Determine two adjacent layers of the circuit substrates and the bottom layer of the circuit substrate along the stacking direction based on the stacking order of each layer of the circuit substrates; A base groove and a plurality of welding grooves are embedded in the packaging substrate, the welding grooves are distributed at the edge of the base groove in a stepped shape, the bottom layer of the circuit substrate is stacked on the base groove, and a welding pad for high-frequency signal or low-frequency signal transmission is arranged in the welding groove, and the welding pad in the welding groove is bonded to the bottom layer of the circuit substrate; After the bottom layer of the circuit substrate is stacked, when each layer of the circuit substrate is stacked, the two adjacent layers of the circuit substrate are interconnected by using the supporting solder balls, and the height of the supporting solder balls is greater than the height of the devices between the two adjacent layers of the circuit substrate; A layer of the airtight enclosure frame surrounding the circuit substrates except the bottom circuit substrate is arranged on the packaging substrate, at least one boss parallel to the circuit substrate is arranged inside the airtight enclosure frame, and the boss and the circuit substrate are grounded to complete the stacking of a layer of the circuit substrate; Until all the circuit substrates are stacked to form a functional circuit, the connecting pillars are fixed to the inner side of the cover according to the positions of the devices integrated in the topmost circuit substrate in the functional circuit, and the cover is fixed directly above the airtight frame to isolate the devices integrated in the topmost circuit substrate, thereby completing the airtight packaging of the functional circuit and forming a three-dimensional stacked module.

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