A three-dimensional airtight packaging structure and packaging method

Abstract

The present invention relates to the field of microelectronic packaging technology, and specifically to a three-dimensional airtight packaging structure and packaging method, comprising a top packaging substrate and a bottom packaging substrate arranged relative to each other, both of which are provided with chip modules; a combined frame structure for forming an airtight structure, the combined frame structure comprising a limiter and a frame member, the relative mating surfaces of the limiter and the frame member being provided with a matching structure; a micro-column structure arranged between the top packaging substrate and the bottom packaging substrate, comprising a micro-column and a micro-solder ball, the micro-column and the micro-solder ball connecting the top packaging substrate and the bottom packaging substrate. The present invention satisfies the interconnection height requirements of the integrated chips on both the upper and lower surfaces of the package and the airtightness requirements of the package by precisely controlling the height consistency of the frame member and the micro-column structure. The relative mating surface structure between the limiter and the frame member improves the alignment efficiency of the top packaging substrate and the bottom packaging substrate, avoiding tedious high-precision alignment operations.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic packaging, and in particular to a three-dimensional airtight packaging structure and a packaging method. Background Art

[0002] Miniaturization, multifunctionality and high performance are important directions for the development of electronic systems. Three-dimensional integration technology based on system-level packaging (SiP) is an important way to achieve miniaturization and multifunctionality of electronic systems. This technology emphasizes the use of adapter plates and packaging substrates to achieve chip stacking in three dimensions, integrating multiple chips, devices and passive components into a single package, thereby increasing the overall integration density. Among them, ceramic packaged SiP has the characteristics of high integration and airtightness, and is the most widely used high-reliability packaging structure. However, the signal interconnect interfaces of traditional ceramic packaged SiP are concentrated on the bottom surface, which cannot meet the requirements of high-density and low-loss transmission of signals in the vertical direction of the RF array, limiting the improvement of system integration density.

[0003] Chinese patent 202210032539.X proposes a double-sided ceramic package structure with integrated interconnect interfaces. Both the base and cover plates of this package are ceramic package substrates, interconnected via metal micropillars. Both the upper and lower outer surfaces of the package feature BGA interfaces, enabling vertical transmission of electrical signals. A metal frame is welded between the base and cover plates to achieve hermetic sealing of the SiP. The implementation of this package structure is difficult because, to meet the chip mounting requirements on the base and cover plates within the package, the frame and metal micropillars must be at least millimeter-high in height. Furthermore, the multiple metal micropillars must exhibit extremely high height consistency to achieve reliable vertical interconnection and hermetic packaging. However, 202210032539.X proposes to use electroplating technology to process the frame and metal micro-pillars. The high frame / metal micro-pillar needs to be achieved through multiple thick-resist photolithography and then electroplating. On the one hand, the process of multiple thick-resist photolithography is difficult and prone to problems such as overlay deviation; on the other hand, the serious thermal mismatch between the electroplated frame / metal micro-pillar and the ceramic packaging substrate will affect the reliability of the overall structure. Therefore, the height of the frame / metal micro-pillar processed by the electroplating process is limited.

[0004] The prior art has not yet provided a solution to these problems. Therefore, a more reasonable technical solution is needed to solve the technical problems existing in the prior art. Summary of the Invention

[0005] To overcome at least one of the above-mentioned defects, the present invention proposes a three-dimensional airtight packaging structure and packaging method, which improves the coordination between the packaging frame and micro-columns between the packaging substrates, thereby improving the packaging precision and airtightness, and simplifying the packaging process.

[0006] In order to achieve the above objectives, the packaging structure disclosed in the present invention can adopt the following technical solutions:

[0007] A three-dimensional airtight packaging structure, comprising:

[0008] A top packaging substrate and a bottom packaging substrate are arranged opposite to each other, chip modules are arranged on the opposite surfaces of the top packaging substrate and the bottom packaging substrate, and interconnection interfaces are arranged on the opposite back surfaces of the top packaging substrate and the bottom packaging substrate;

[0009] A combined enclosure structure is provided between the top packaging substrate and the bottom packaging substrate to form an airtight structure, the combined enclosure structure comprising a position-limiting member and an enclosure member correspondingly provided on the top packaging substrate and the bottom packaging substrate and mating with each other, and a registration structure is provided on the mating surfaces of the position-limiting member and the enclosure member;

[0010] The micro-column structure arranged between the top packaging substrate and the bottom packaging substrate includes a micro-column and a micro-solder ball that are conductively matched. The micro-column and the micro-solder ball conduct the top packaging substrate and the bottom packaging substrate.

[0011] The three-dimensional airtight packaging structure disclosed above precisely aligns the top and bottom packaging substrates through a combined frame structure, improving installation accuracy. Furthermore, the micro-pillar structure provided between the top and bottom packaging substrates enables electrical conduction, and the height of the micro-pillar structure is the same as that of the combined frame structure, facilitating a good contact seal between the top and bottom packaging substrates after alignment. Using this airtight packaging structure disclosed in the present invention, the entire assembly can be welded and sealed simultaneously, avoiding the high dimensional requirements and difficulty in ensuring weld quality associated with precision welding. Heat and welding processes can be performed simultaneously to achieve the formation of the entire airtight packaging structure.

[0012] Furthermore, the present invention places the chip module within the package cavity and performs an anti-interference shielding process. Chip anti-interference can be achieved through a variety of methods, which are not limited here, and one feasible option is optimized as follows: the chip module includes a chip, a chip solder layer for soldering the chip to the top package substrate or the bottom package substrate, and a shielding member that covers the chip to shield interference, with an air gap formed between the shielding member and the chip. When adopting this solution, chips are placed on both the top package substrate and the bottom package substrate, and the chips are connected and fixed by the chip solder layer; and the shielding member is a lid-shaped cover that is fixed to the outside of the chip by solder connection and covers it.

[0013] Furthermore, in the present invention, a registration structure is used to align the frame member and the position limiting member, allowing the frame member to form a closed cavity at the top and bottom packaging substrates. The possible configurations for the registration structure are not limited to a single one. Here, an optimization is provided and one feasible option is presented: the registration structure includes a recessed structure and a raised structure. When the position limiting member and the frame member are aligned and matched, the recessed structure and the raised structure tightly fit together. Furthermore, an airtight connection layer is provided between the recessed structure and the raised structure. When this configuration is used, the recessed structure and the raised structure form a Z-shaped, V-shaped, or zigzag-shaped mating surface. Through the precise mating of these surfaces, the top and bottom packaging substrates can be quickly aligned, ensuring both accurate and efficient connection.

[0014] Furthermore, to achieve a more stable assembly frame structure, the mounting structure is optimized and a feasible option is provided: a connecting via is provided on the bottom package substrate corresponding to the assembly frame structure. With this solution, the connecting via and the assembly frame structure can be sealed with solder.

[0015] Furthermore, the micro-pillars are used to conduct electricity between the top package substrate and the bottom package substrate. The available solutions are not limited to a single one. Here, an optimization is made and one feasible option is given: the micro-pillars extend from the bottom package substrate to the top package substrate, and the micro solder balls are connected and cooperated with the top ends of the micro-pillars.

[0016] Furthermore, the micropillar structure configuration is optimized and a feasible option is proposed: both the top and bottom package substrates are provided with connecting pads, through which the micropillars and micro-solder balls connect the top and bottom package substrates. With this solution, signal conduction is achieved after the micropillars are securely connected to the connecting pads.

[0017] The above content describes the airtight packaging structure. The present invention also discloses a solution for achieving the airtight packaging, which will now be described.

[0018] A three-dimensional airtight packaging method for preparing the airtight packaging structure described above, comprising:

[0019] Connecting conductive seats are correspondingly provided on the top packaging substrate and the bottom packaging substrate;

[0020] A stopper and a frame are respectively provided on the top package substrate and the bottom package substrate, wherein the frame is provided synchronously with the micro-column structure and the end faces are flush, and an airtight solder layer is provided on the relative mating surfaces of the stopper and / or the frame;

[0021] fixing the micro solder balls to the end faces of the micro pillars;

[0022] and at least correspondingly connecting and fixing the chip to the top package substrate and the bottom package substrate;

[0023] Align the relative mating surfaces of the limiting part and the surrounding frame part, heat and pressurize the upper end surface of the top packaging substrate for airtight welding, and simultaneously weld the micro-column structure to connect the top packaging substrate and the bottom packaging substrate. During the welding process, vacuum is drawn inside the packaging cavity.

[0024] The disclosed packaging method utilizes a combined frame structure of the top and bottom packaging substrates to align and limit the structure. The simultaneous placement of the frame and micropillar structure maintains flush end faces, improving precision during the airtight construction process. The method also achieves this by heating the top and bottom packaging substrates together after assembly, avoiding the stress caused by localized temperature differences associated with point-by-point welding methods like laser welding that could impact the reliability of the packaging structure.

[0025] Furthermore, the present invention simultaneously prepares the frame and micropillars during fabrication and separates them after connection. Specifically, this optimization provides the following feasible approach: a subtractive process is used to process a flat sheet of material to form the integral connection between the frame and micropillars, with a flat surface of the flat sheet serving as the end face of the frame and micropillars. A removable process line structure is provided at the connection between the frame and micropillars. After the frame and micropillars are connected and secured to the top or bottom package substrate, the process line structure is removed to separate the frame and micropillars. Using this approach, the frame and micropillars are processed as a single unit, maintaining a consistent connection height after connection and securing, facilitating connection and securing of the top and bottom package substrates, and maintaining the dimensional precision of the top and bottom package substrates after connection.

[0026] Furthermore, to ensure airtight welding, the surfaces of the frame and micro-pillar structure are processed. Here, we provide an optimization and a feasible option: after processing the frame and micro-pillars, the outer surfaces of the frame and micro-pillars are coated. Furthermore, there is no single restriction on the order in which the chip module is installed. For example, in some solutions, the chip and shielding components can be installed simultaneously, while in others, they can be installed separately. Here, we provide an optimization and a feasible option: after installing the limiter and frame, the shielding component is installed to cover the chip.

[0027] Compared with the prior art, some of the beneficial effects of the technical solution disclosed in the present invention include:

[0028] By jointly fabricating the frame and micro-pillar structure, the present invention allows for more precise dimensional control of both, achieving micron-level consistency. This ensures that both the top and bottom integrated chips meet interconnect height requirements and the package's airtightness. The mating surface structure between the stopper and the frame improves the alignment efficiency of the top and bottom package substrates, avoiding tedious high-precision alignment operations. The package structure provided by the present invention boasts high precision, a simple packaging process, and flexible and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only represent some embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic diagram of the structure at the top packaging substrate.

[0031] Figure 2 It is a schematic diagram of the structure at the bottom packaging substrate.

[0032] Figure 3 This is a structural diagram of the top package substrate and the bottom package substrate when aligned.

[0033] Figure 4 This is a structural diagram after the top package substrate and the bottom package substrate are aligned and welded.

[0034] Figure 5 This is a schematic diagram of the local structure of the basic welding point between the top package substrate and the bottom package.

[0035] Figure 6 Schematic diagram of the packaging process.

[0036] In the above drawings, the meanings of the various reference numerals are as follows:

[0037] 1. Top package substrate; 2. Connecting conductor; 3. Limiting piece; 4. Airtight welding layer; 5. Chip welding layer; 6. Chip; 7. Shielding piece; 8. Bottom package substrate; 9. Frame; 10. Micro pillar; 11. Micro solder ball. DETAILED DESCRIPTION

[0038] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0039] In view of the fact that the high-precision alignment process of chip packaging in the prior art is cumbersome and the packaging effect is not ideal, the following embodiments optimize and overcome the problems existing in the prior art.

[0040] Example 1

[0041] like Figures 1 to 5 As shown, this embodiment provides a three-dimensional hermetic packaging structure, which aims to improve the alignment accuracy of the packaging mechanism, ensure the reliability of the hermetic packaging, and improve the convenience of alignment packaging.

[0042] As the airtight packaging structure provided in this embodiment, one of its structures includes:

[0043] The top packaging substrate 1 and the bottom packaging substrate 8 are arranged opposite to each other, and chip modules are arranged on the opposite surfaces of the top packaging substrate 1 and the bottom packaging substrate 8, and interconnection interfaces are arranged on the opposite back surfaces of the top packaging substrate 1 and the bottom packaging substrate 8.

[0044] Preferably, in this embodiment, the interconnection interface adopts a BGA interface.

[0045] The top package substrate 1 and the bottom package substrate 8 may be ceramic package substrates.

[0046] In this embodiment, the chip module is disposed within the package cavity and subjected to anti-interference shielding. Anti-interference protection of the chip can be achieved in a variety of ways, and this embodiment is not intended to be the only one. It optimizes and adopts one feasible option: the chip module includes a chip 6, a chip solder layer 5 for soldering the chip 6 to the top package substrate 1 or the bottom package substrate 8, and a shielding member 7 for covering the chip 6 to shield interference, with an air gap formed between the shielding member 7 and the chip 6. When such a solution is adopted, the chip 6 is disposed on both the top package substrate 1 and the bottom package substrate 8, and the chip 6 is connected and fixed by the chip solder layer 5; and the shielding member 7 is a lid-shaped cover that is fixed to the outside of the chip 6 by solder connection and covers it.

[0047] Preferably, the chip solder layer 5 used in this embodiment includes a structure formed by sintering nanosilver.

[0048] The second structure of the airtight packaging structure provided in this embodiment includes:

[0049] A combined frame structure is arranged between the top packaging substrate 1 and the bottom packaging substrate 8 to form an airtight structure. The combined frame structure includes a limit member 3 and a frame member 9 that are correspondingly arranged on the top packaging substrate 1 and the bottom packaging substrate 8 and relatively matched. The relative matching surfaces of the limit member 3 and the frame member 9 are provided with a matching structure.

[0050] Preferably, the frame member 9 in this embodiment is provided on the bottom package substrate 8, and the position limiting member 3 is provided on the top package substrate 1. The opposing mating surfaces of the position limiting member 3 and the frame member 9 form a step-like structure.

[0051] Preferably, in the present invention, the alignment structure is used to align the enclosure member 9 and the limiting member 3, so that the enclosure member 9 can enclose a closed cavity at the top packaging substrate 1 and the bottom packaging substrate 8. The possible solutions for the alignment structure are not limited to a single solution. This embodiment optimizes and adopts one feasible option: the alignment structure includes a recessed structure and a raised structure. When the limiting member 3 and the enclosure member 9 are aligned and matched, the recessed structure and the raised structure are tightly fitted; and an airtight connection layer is also provided between the recessed structure and the raised structure. When such a solution is adopted, the recessed structure and the raised structure form a Z-shaped, V-shaped, or sawtooth-shaped mating surface. Through the precise mating of the mating surfaces, the top packaging substrate 1 and the bottom packaging substrate 8 can be quickly aligned, ensuring both the accuracy and efficiency of the connection.

[0052] Preferably, in this embodiment, the concave structure and the convex structure are combined to form a step shape, thereby achieving alignment and positioning.

[0053] In this embodiment, the airtight connection layer is a solder layer, and after being heated and pressurized, the mating surfaces are welded and sealed. The airtight connection layer uses Au80Sn20 as the connection solder.

[0054] In this embodiment, to provide a more stable assembly frame structure, the mounting structure is optimized and a feasible option is adopted: a connecting via 2 is provided on the bottom package substrate 8 corresponding to the assembly frame structure. With this solution, the connecting via 2 and the assembly frame structure can be sealed using solder.

[0055] Preferably, the solder connecting the conductive base 2 and the combined frame structure can be made of Au80Sn20 alloy material.

[0056] The third structure of the airtight packaging structure provided in this embodiment includes:

[0057] The micro-column structure disposed between the top package substrate 1 and the bottom package substrate 8 includes a micro-column 10 and a micro-solder ball 11 that are conductively matched. The micro-column 10 and the micro-solder ball 11 are conductively connected to the top package substrate 1 and the bottom package substrate 8 .

[0058] The micro-pillars 10 are used to conduct electricity between the top package substrate 1 and the bottom package substrate 8 . The available solutions are not limited to a single one. This embodiment optimizes and adopts one feasible option: the micro-pillars 10 extend from the bottom package substrate 8 to the top package substrate 1 , and the micro-solder balls 11 are connected to the top ends of the micro-pillars 10 .

[0059] Preferably, this embodiment optimizes the arrangement of the micropillar structure and adopts one feasible option: both the top package substrate 1 and the bottom package substrate 8 are provided with connecting conductive blocks 2. The micropillars 10 and micro solder balls 11 connect the top package substrate 1 and the bottom package substrate 8 via the connecting conductive blocks 2. With this solution, signal conduction is achieved after the micropillars 10 are fixedly connected to the connecting conductive blocks 2.

[0060] Preferably, in this embodiment, the frame 9 and the micro-columns 10 are both made of metal material, and have a height of 1 mm to 2 mm. The flatness error of the end faces of the frame 9 and the micro-columns 10 is less than 5 μm.

[0061] Preferably, in this embodiment, the diameter of the micro-solder ball 11 is greater than or equal to the diameter of the micro-column 10. The matching requirements of the diameter of the micro-solder ball 11 and the stopper 3 (including the solder layer) are as follows: after the micro-solder ball 11 is pre-placed on the upper surface of the micro-column 10, the distance between the top surface of the micro-solder ball 11 and the upper surface of the micro-column 10 is H1, the thickness of the conductive connection seat on the top packaging substrate 1 is H2, the maximum distance between all step surfaces of the stopper 3 and the first welding surface is D1, and the minimum distance is D2, then D1>H1+H2>D2.

[0062] The three-dimensional airtight packaging structure disclosed above precisely aligns the top packaging substrate 1 and the bottom packaging substrate 8 through a combined frame structure, improving installation accuracy. Furthermore, the micro-pillar structure provided between the top packaging substrate 1 and the bottom packaging substrate 8 enables electrical conduction, and the height of the micro-pillar structure is the same as that of the combined frame structure, facilitating a good contact seal between the top packaging substrate 1 and the bottom packaging substrate 8 after alignment. The airtight packaging structure disclosed in this embodiment allows for simultaneous welding and sealing after overall assembly, avoiding the high dimensional requirements and difficulty in ensuring welding quality associated with precision welding. Heat and welding processes can be performed simultaneously to achieve the formation of the entire airtight packaging structure.

[0063] Example 2

[0064] The above embodiment describes the airtight packaging structure. This embodiment also discloses a solution for achieving the airtight packaging, which will now be described.

[0065] like Figure 6 As shown, a three-dimensional airtight packaging method for preparing the airtight packaging structure described above includes the following steps:

[0066] S01 : Connecting vias 2 are correspondingly provided on the top packaging substrate 1 and the bottom packaging substrate 8 .

[0067] S02: A limiter 3 and a frame member 9 are respectively arranged on the top packaging substrate 1 and the bottom packaging substrate 8, wherein the frame member 9 is synchronously arranged with the micro-column structure and the end faces are flush, and an airtight solder layer is arranged on the relative mating surfaces of the limiter 3 and / or the frame member 9.

[0068] Specifically, the following steps are used when setting the limiter 3:

[0069] S021: Setting a limiter 3 along the periphery of the welding surface of the top package substrate 1 by thick resist photolithography combined with electroplating.

[0070] S022: Au80Sn20 solder is provided on the relative mating surfaces of the limiting member 3 by micro-seam welding, electroplating or evaporation to serve as an airtight connection layer, wherein the thickness of the airtight connection layer is 5 μm to 20 μm.

[0071] S03 : Fixing the micro solder balls 11 to the end surfaces of the micro pillars 10 .

[0072] Preferably, micro solder balls 11 are pre-placed on the upper surfaces of all micro pillars 10 using a laser ball implantation process.

[0073] S04: Connect and fix the chip 6 to the top package substrate 1 and the bottom package substrate 8 accordingly.

[0074] There is no single limitation on the order of setting the chip module. For example, in some schemes, the chip 6 and the shielding member 7 can be set at the same time, and in some schemes, they can be set separately. This embodiment is optimized and adopts one of the feasible options: after setting the limit member 3 and the frame member 9, the shielding member 7 is set to cover the chip 6.

[0075] Preferably, the chip and the shielding frame are mounted by nano-silver sintering.

[0076] After the chip 6 is mounted, the shielding member 7 is mounted by a nano-silver sintering process. The shielding member 7 is constructed in a cover shape to cover the chip 6 .

[0077] S05: Align the relative mating surfaces of the limiting member 3 and the surrounding frame member 9, heat and pressurize the upper end surface of the top packaging substrate 1 to perform airtight welding, and simultaneously weld the micro-column structure to connect the top packaging substrate 1 and the bottom packaging substrate 8, and evacuate the packaging cavity during the welding process.

[0078] In the process of S05 , the limiting member 3 and the surrounding frame member 9 are stacked and welded to form a three-dimensional airtight packaging structure.

[0079] Preferably, in this embodiment, the frame member 9 and micropillars 10 are fabricated simultaneously during fabrication and separated after connection. Specifically, this optimization employs the following feasible method: a subtractive method is used to process a flat sheet of material to form the integral connection between the frame member 9 and micropillars 10, with a flat surface of the flat sheet serving as the end face of the frame member 9 and micropillars 10. A removable process line structure is provided at the connection between the frame member 9 and micropillars 10. After the frame member 9 and micropillars 10 are connected and secured to the top package substrate 1 or the bottom package substrate 8, the process line structure is removed to separate the frame member 9 and micropillars 10. With this solution, the frame member 9 and micropillars 10 are processed as a single unit, maintaining a consistent connection height after connection and securing, facilitating connection and securing of the top package substrate 1 and the bottom package substrate 8, and maintaining the dimensional precision of the top package substrate 1 and the bottom package substrate 8 after connection.

[0080] The preparation of the frame 9 and the micro-columns 10 specifically includes the following steps:

[0081] S051: providing a metal plate that has been ground and polished for processing the frame 9 and the micro-columns 10 . The thickness of the metal plate is 1-2 mm, which is equal to the height of the frame 9 and the micro-columns 10 .

[0082] S052: Using a water-guided laser cutting method, the excess material between the frame member 9 and the micro-columns 10 is removed from the upper surface of the metal plate until the thickness of the process line is 0.3 mm from the bottom surface. The process line connects the frame member 9 and all the micro-columns 10 on the lower surface of the metal plate.

[0083] S053: Processing the frame member 9 from the lower surface of the metal plate by using a water-guided laser cutting method.

[0084] S054: a 4-8 μm Ni plating layer and a 1-2 μm Au plating layer are sequentially provided on the outer surface of the composite structure of the frame member 9 and the micro-columns 10 .

[0085] Preferably, solder is provided on the soldering surface of the bottom package substrate 8 by a method of screen printing or evaporation as a gas-tight connection layer. The solder is Au80Sn20 alloy and is used to connect the surrounding frame 9 and the microcolumns 10 .

[0086] Preferably, vacuum eutectic welding or vacuum reflow welding is used to weld the composite structure of the frame 9 and the micro-columns 10 to the welding surface of the bottom packaging substrate 8. During the welding process, a flat-plate-structured pressing block is placed on the surface of the frame 9 and the micro-columns 10. The process line also plays a role in uniform stress, ensuring the high consistency of the frame and the metal micro-columns after welding.

[0087] Preferably, after the surrounding frame 9 and the micro-columns 10 are connected and fixed, a water-guided laser cutting method is used to remove the process lines.

[0088] The packaging method disclosed above uses a combined frame structure of the top and bottom packaging substrates 1 and 8 to align and limit the components. The simultaneous placement of the frame member 9 and the micropillar structure maintains flush end faces, facilitating precision during the airtight construction process. The packaging method also achieves this by heating the top and bottom packaging substrates 1 and 8 after they are joined, avoiding the impact of localized temperature differences on the reliability of the packaging structure caused by point-by-point welding.

[0089] The above are the implementation methods listed in this embodiment, but this embodiment is not limited to the above optional implementation methods. Those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods. Anyone can derive other various implementation methods based on the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the scope of protection of this embodiment. The scope of protection of this embodiment should be based on the definition in the claims.

Claims

1. A three-dimensional airtight packaging structure, characterized in that: include: A top packaging substrate (1) and a bottom packaging substrate (8) are arranged opposite to each other, chip modules are arranged on opposite surfaces of the top packaging substrate (1) and the bottom packaging substrate (8), and interconnection interfaces are arranged on opposite back surfaces of the top packaging substrate (1) and the bottom packaging substrate (8); A combined frame structure is provided between a top packaging substrate (1) and a bottom packaging substrate (8) to form an airtight structure, the combined frame structure comprising a limiting member (3) and a frame member (9) which are correspondingly provided on the top packaging substrate (1) and the bottom packaging substrate (8) and are relatively matched, and a matching structure is provided on the relative matching surfaces of the limiting member (3) and the frame member (9); The alignment structure includes a recessed structure and a raised structure. When the limiting member (3) and the surrounding frame member (9) are aligned and matched, the recessed structure and the raised structure are tightly fitted together. An airtight connection layer is also provided between the recessed structure and the raised structure. A micro-column structure disposed between a top package substrate (1) and a bottom package substrate (8), comprising a plurality of conductively matched micro-columns (10) and micro-solder balls (11), wherein the micro-columns (10) and micro-solder balls (11) are conductively connected between the top package substrate (1) and the bottom package substrate (8); After the micro solder ball (11) is pre-placed on the upper surface of the micro column (10), the distance between the top surface of the micro solder ball (11) and the upper surface of the micro column (10) is H1, the thickness of the conductive connection seat on the top packaging substrate (1) is H2, the maximum distance between all step surfaces of the limiter (3) and the first welding surface is D1, and the minimum distance is D2, then D1>H1+H2>D2.

2. The three-dimensional airtight packaging structure according to claim 1, characterized in that: The chip module comprises a chip (6), a chip soldering layer (5) for soldering the chip (6) to a top package substrate (1) or a bottom package substrate (8), and a shielding member (7) for covering the chip (6) to shield interference, wherein an air gap is formed between the shielding member (7) and the chip (6).

3. The three-dimensional airtight packaging structure according to claim 1, characterized in that: A connecting conductive seat (2) is provided on the bottom packaging substrate (8) corresponding to the combined frame structure.

4. The three-dimensional airtight packaging structure according to claim 1, characterized in that: The micro-column (10) extends from the bottom packaging substrate (8) to the top packaging substrate (1), and the micro solder ball (11) is connected and matched with the top end of the micro-column (10).

5. The three-dimensional airtight packaging structure according to claim 1 or 4, characterized in that: The top package substrate (1) and the bottom package substrate (8) are both provided with a connecting conductive seat (2), and the micro-columns (10) and the micro-solder balls (11) conduct electricity between the top package substrate (1) and the bottom package substrate (8) through the connecting conductive seat (2).

6. A three-dimensional airtight packaging method for preparing the airtight packaging structure according to any one of claims 1 to 5, characterized in that: include: Connecting conductive seats (2) are correspondingly provided on the top packaging substrate (1) and the bottom packaging substrate (8); A limiting member (3) and a surrounding frame member (9) are respectively provided on the top packaging substrate (1) and the bottom packaging substrate (8), wherein the surrounding frame member (9) is provided synchronously with the micro-column structure and the end faces are flush, and an airtight solder layer is provided on the relative mating surfaces of the limiting member (3) and / or the surrounding frame member (9); Fixing the micro solder balls (11) to the end faces of the micro pillars (10); Connecting and fixing the chip (6) to the top packaging substrate (1) and the bottom packaging substrate (8) accordingly; The relative mating surfaces of the limiting member (3) and the surrounding frame member (9) are aligned and joined, and airtight welding is performed by heating and pressurizing the upper end surface of the top packaging substrate (1). The micro-column structure is simultaneously welded to connect the top packaging substrate (1) and the bottom packaging substrate (8), and the packaging cavity is vacuumed during the welding process.

7. The three-dimensional airtight packaging method according to claim 6, characterized in that: A subtractive method is used to process a flat plate material to obtain a connected integral body of the frame member (9) and the microcolumn (10), wherein a plane of the flat plate material serves as the end face of the frame member (9) and the microcolumn (10); a removable process line structure is provided at the connection between the frame member (9) and the microcolumn (10); after the frame member (9) and the microcolumn (10) are connected and fixed to the top package substrate (1) or the bottom package substrate (8), the process line structure is removed to separate the frame member (9) from the microcolumn (10).

8. The three-dimensional airtight packaging method according to claim 7, characterized in that: After the frame member (9) and the micro-columns (10) are processed, coatings are provided on the outer surfaces of the frame member (9) and the micro-columns (10).

9. The three-dimensional airtight packaging method according to claim 6 or 7, characterized in that: After the limiting member (3) and the surrounding frame member (9) are set, the shielding member (7) is set to cover the chip (6).

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