Sintering device and method for metal foil abutted seam interconnection

Abstract

The invention relates to the technical field of metal sintering interconnection, and discloses a sintering device and method for metal foil abutted seam interconnection, and the sintering device comprises a heating platform, a multi-degree-of-freedom direct writing mechanical arm, a shielding gas device and a high-temperature thermal imager. The sintering device can be suitable for metal foil samples of different shapes and sizes, large-area uniform heating is achieved, the sintered samples are heated uniformly, and the interconnection quality of the sintered samples is improved. A multi-layer gradient sintering method is used in the sintering process, and the curing effect of each time of soldering paste coating and the metallurgical bonding strength between different layers can be guaranteed. By means of the gradient sintering method, the service performance of the sintered metal foil can be guaranteed, it is guaranteed that the resistivity of a sintered interconnection area is lower while the sintering interconnection strength is guaranteed, better heat conduction and electric conduction effects are achieved, and meanwhile the interconnection reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal sintering interconnection, and more particularly to a sintering device and method for metal foil seam interconnection. Background Art

[0002] How to prepare high-performance large-area metal foil scattering surfaces for aerospace has become a core issue faced by researchers in the aerospace field. Since larger-area metal foils cannot be manufactured in one go, multiple small-sized metal foils need to be spliced ​​and interconnected. The interconnection quality of the spliced ​​interconnection interface will affect the working and service performance of the interconnected metal foils.

[0003] Currently, welding and sintering are commonly used methods for interconnecting metal foil seams. However, the existing welding and sintering methods are not suitable for the connection size and service effect of the interconnected metal foils, thus affecting the subsequent service performance of the metal foils. Summary of the invention

[0004] In view of the shortcomings of the current sintering interconnection devices and methods, the present invention proposes a sintering device and method for metal foil patchwork interconnection, which can improve the reliability of metal foil sintering interconnection and improve the subsequent service performance of the interconnected metal foil.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A sintering device for interconnecting metal foil seams, comprising:

[0007] The heating platform is composed of a plurality of single-degree-of-freedom ceramic heating sheet mechanisms arranged side by side, wherein the single-degree-of-freedom ceramic heating sheet mechanisms include a vertically arranged telescopic member and a ceramic heating sheet installed at the top end of the telescopic member; the plurality of telescopic members are controlled to move up and down at their respective top ends to deform the corresponding plurality of ceramic heating sheets as a whole into sintering platforms of different shapes, and the flexible metal foil sample is bonded and fixed on the sintering platform; the ceramic heating sheet is controlled to be opened and closed by the heating device;

[0008] A multi-degree-of-freedom direct writing robot arm, with a direct writing needle mechanism installed at the end, can directly write and apply solder paste to the metal foil surface joints on the fixed metal foil sample by setting parameters of the multi-degree-of-freedom direct writing robot arm;

[0009] A protective gas device is installed outside the single-degree-of-freedom ceramic heating plate mechanism and is used to spray sintering protective gas into the joint of the metal foil;

[0010] A high-temperature thermal imager is installed outside the single-degree-of-freedom ceramic heating plate mechanism to observe the heat distribution on the surface of the metal foil sample during the sintering process.

[0011] Preferably, each of the ceramic heating plates is controlled by its own independent power supply; the size of the ceramic heating plates is determined by the metal foil sample. When the surface curvature of the metal foil sample is large, the size of the ceramic heating plates needs to be reduced to form a sintering platform with a larger curvature to match the metal foil sample.

[0012] Preferably, the direct writing needle mechanism includes a needle tube capable of storing sintered solder paste and a needle head capable of flowing out sintered solder paste, and the multi-degree-of-freedom direct writing robot arm needs to control the needle head to apply solder paste to the metal foil seam in a direction perpendicular to the cutting plane of the metal foil seam surface.

[0013] Preferably, the robotic arm on the multi-degree-of-freedom direct-writing robotic arm is a 4-axis robotic arm.

[0014] A sintering method for metal foil patchwork interconnection, using one of the above-mentioned sintering devices for metal foil patchwork interconnection, comprises the following steps:

[0015] S1. Adjust the height of each ceramic heating plate in the heating platform so that the composed sintering platform is adapted to the size of the flexible metal foil sample;

[0016] S2, fixing the metal foil sample onto the sintering platform;

[0017] S3, adjusting the parameters of the multi-degree-of-freedom direct writing robot arm, applying the sintered solder paste on the surface of the metal foil joint, and the coating amount of the first layer of solder paste is such that the metal foil joint area is not completely filled;

[0018] S4. Using a layered gradient coating and sintering method, after applying solder paste to the metal foil joints once, first open the protective gas device and the heating device in the heating platform to sinter the applied solder paste to remove organic components; then close the protective gas device and the heating device in the heating platform, and apply the sintered solder paste to the surface of the metal foil joints again to form contact with the previous layer of applied solder paste; open the protective gas device and the heating device in the heating platform again to sinter the newly applied solder paste to remove organic components, and solidify the previous layer of applied solder paste;

[0019] S5. Cycle coating and sintering to form a gradient layered sintering structure.

[0020] Preferably, the sintered solder paste in step S3 is a nano-metal solder paste, which is composed of nano-metal and an organic dispersed adhesive.

[0021] Preferably, the parameters of the multi-degree-of-freedom direct writing robot arm include moving path, direct writing pressure and moving speed; wherein the moving path is determined by the geometric position of the seam on the metal foil surface, and the robot arm can perform path planning along the seam path through programming of the path function; the direct writing pressure is the air pressure in the needle tube, which is used to determine the amount of solder paste extruded per unit time; the moving speed is the moving speed of the needle head;

[0022] In step S3, the parameters of the multi-degree-of-freedom direct writing robot arm are directly adjusted based on the size of the metal foil seam. If the depth-to-width ratio of the metal foil sample is relatively small, the direct writing pressure needs to be increased and the direct writing speed needs to be reduced to ensure the extrusion of the solder paste; if the depth-to-width ratio of the metal foil sample is relatively large, the direct writing pressure needs to be reduced and the direct writing speed needs to be increased to ensure the flow of the solder paste.

[0023] Preferably, the number of cycles of the gradient sintering process is determined by the size of the metal foil.

[0024] Preferably, the heating and sintering time of each layer of applied solder paste is at least 10 minutes.

[0025] Preferably, the protective gas device is linked with the heating device in the heating platform; before each heating process starts, the protective gas device should work in advance for 3 to 5 seconds, and after each heating process ends, the protective gas device should continue to work for 15 to 20 seconds.

[0026] Compared with the prior art, the sintering device and sintering method of the present invention have the following advantages:

[0027] The invention discloses a sintering device for interconnecting metal foil seams, wherein the heating platform can make the ceramic heating plate adapt to the metal foil sintering sample by controlling each telescopic component, thereby ensuring a more uniform temperature distribution and improving the heating efficiency.

[0028] The device of the present invention realizes large-area uniform heating of metal foil samples of different sizes and shapes, can realize large-area metal foil interconnection, makes the sintered samples heated evenly, improves the connection strength and reliability of the interconnected metal foil sintering, improves the interconnection quality of the sintered samples, and has the characteristics of wide applicability, high sintering efficiency, and good sintering interconnection effect.

[0029] At the same time, compared with the currently used welding sintering method, the present invention uses nano metal as sintering brazing material, and through the small size effect of nano metal, the sintering interconnection temperature is greatly reduced, ensuring the integrity of the sintered substrate and the metal foil. That is, the present invention uses nano metal materials as brazing materials to achieve low-temperature connection, which not only protects the substrate and metal foil materials, but also ensures the excellent performance of sintering interconnection, and finally can form a low-resistance and high-reliability metal foil patchwork interconnection.

[0030] In addition, the present invention uses a layered gradient coating and sintering method during the sintering process, which ensures that the organic matter in the sintered solder paste is completely volatilized and that there are no organic components in the interconnected sintering interface, thereby ensuring the curing effect of each solder paste coating and the metallurgical bonding strength between different layers, thereby improving the performance of the interconnected sintering interface.

[0031] The present invention can ensure the service performance of the sintered metal foil through the gradient sintering method, ensure the sintered interconnection strength while ensuring lower resistivity in the sintered interconnection area, achieve better heat conduction and electrical conduction effects, and also improve interconnection reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0033] Figure 1 It is a schematic structural diagram of a heating platform adapted to a curved surface in a sintering device of the present invention.

[0034] Figure 2 This is a schematic diagram of the external structure of a single-degree-of-freedom ceramic heating plate mechanism.

[0035] Figure 3 This is a schematic diagram of the internal structure of a single-degree-of-freedom ceramic heating plate mechanism.

[0036] Figures 4-a, 4-b, and 4-c are schematic diagrams of three types of metal foil samples to which the present invention can be applied.

[0037] Figure 5 Schematic diagram of the process of direct writing solder paste coating on metal foil seams by a multi-degree-of-freedom direct writing robot arm.

[0038] Figures 6-a, 6-b, and 6-c are schematic diagrams of coating paths for the three metal foil seams in Figures 4-a, 4-b, and 4-c, respectively.

[0039] Figure 7 Schematic diagram of the process of layered gradient coating sintering.

[0040] In the figure: 1-heating platform, 2-multi-degree-of-freedom direct writing robot arm, 3-telescopic component, 4-ceramic heating plate, 5-needle tube, 6-needle head, 7-metal foil sample, 8-metal foil seam. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] Example:

[0045] See also Figure 1-7 The present embodiment provides a sintering device and method for metal foil patchwork interconnection, which can not only be applicable to metal foil samples of different shapes and sizes, realize large-area uniform heating, make the sintered samples heated evenly, and improve the interconnection quality of the sintered samples, but also ensure the curing effect of each application of solder paste and the metallurgical bonding strength between different layers, ensure the service performance of the sintered metal foil, ensure the sintered interconnection strength while ensuring the lower resistivity of the sintered interconnection area, achieve better heat conduction and electrical conduction effects, and also improve the interconnection reliability.

[0046] Specifically, the present invention provides a sintering device for interconnecting metal foil seams, comprising a heating platform 1, a multi-degree-of-freedom direct writing robot arm 2, a protective gas device and a high-temperature thermal imager.

[0047] Among them, Figure 1-3As shown, the heating platform 1 is composed of a plurality of single-degree-of-freedom ceramic heating plate mechanisms arranged side by side, and the single-degree-of-freedom ceramic heating plate mechanisms include a vertically arranged telescopic member 3 and a ceramic heating plate 4 installed at the top end of the telescopic member 3; the plurality of telescopic members 3 control the up and down movement of their respective top ends to deform the corresponding plurality of ceramic heating plates 4 as a whole into sintering platforms of different shapes, so that flexible metal foil samples of different shapes and sizes can be attached and fixed on the sintering platform; the ceramic heating plate 4 is controlled to be opened and closed by the heating device.

[0048] In a further specific embodiment, the telescopic member 3 is a single-degree-of-freedom metal rod, such as an electric cylinder or a pneumatic cylinder. The metal rod serving as a piston in the cylinder can move in a vertical direction. The length of the metal rod is determined by the size of the metal foil sample. The shape of the end ceramic heating plate 4 is combined through the up and down movement of each metal rod, which can be suitable for fixing metal foil samples 7 of different shapes and sizes.

[0049] In a further specific embodiment, each ceramic heating plate 4 is controlled by its own independent power supply, that is, each ceramic heating plate 4 can work independently, and the effect of heating along the seam path can be achieved by selectively turning on and off the corresponding power supply of the ceramic heating plate 4, and the remaining ceramic heating plates 4 form a support, adapting to the shape of the metal foil sample, and heating the ceramic plates to heat and sinter the solder paste.

[0050] The size of the ceramic heating plate 4 is determined by the metal foil sample 7. When the surface curvature of the metal foil sample is large, the size of the ceramic heating plate 4 needs to be reduced to form a sintering platform with a larger curvature to match the metal foil sample 7, so that the fitting area between the heating platform 1 and the sintered sample is larger, thereby obtaining a better heating effect.

[0051] like Figure 5 As shown, a direct writing needle mechanism is installed at the end of the multi-degree-of-freedom direct writing robot arm 2. By setting parameters of the multi-degree-of-freedom direct writing robot arm 2, solder paste can be directly applied to the metal foil surface seam on the fixed metal foil sample 7.

[0052] In a further specific embodiment, the direct writing needle mechanism includes a needle tube 5 capable of storing sintered solder paste and a needle head 6 capable of flowing out the sintered solder paste. In order to ensure the coating effect of the solder paste, the multi-degree-of-freedom direct writing robot arm 2 needs to control the needle head 6 to apply the solder paste to the metal foil seam 8 perpendicular to the cutting plane direction of the metal foil seam surface. This direct writing method from a 90° direction can ensure the filling effect of the solder paste on the metal foil seam 8.

[0053] In addition, the robot arm on the multi-degree-of-freedom direct writing robot arm 2 is a 4-axis robot arm, which is used to directly write solder paste to the fixed metal foil joint 8. Through path planning and parameter setting, it can be suitable for the coating of metal foil sintering solder paste of different shapes and sizes.

[0054] The protective gas device is installed outside the single-degree-of-freedom ceramic heating plate mechanism to spray sintering protective gas into the metal foil joint 8.

[0055] The protective gas device in the present invention is preferably a cylinder that can spray argon protective gas. Since sintering in an air environment will cause oxidation of the sintered sample, the present invention uses argon gas as the sintering protective gas for the metal foil sintering interconnection of high-temperature easily oxidized metals to prevent the metal foil from oxidizing during the sintering process, thereby improving the joint sintering interconnection effect.

[0056] The high-temperature thermal imager is generally a thermal imaging camera installed on the outside of the single-degree-of-freedom ceramic heating plate mechanism to observe the heat distribution on the surface of the metal foil sample during the sintering process, determine the temperature distribution of the sintering, and thus evaluate the heating effect to ensure that the heating area is the area where the metal foil seam 8 is located, thereby improving the sintering interconnection efficiency and improving the sintering reliability.

[0057] The present invention provides a sintering method for interconnecting metal foil seams, using the above-mentioned sintering device for interconnecting metal foil seams, and comprising the following steps:

[0058] S1, adjusting the height of each ceramic heating plate 4 in the heating platform 1 so that the formed sintering platform is adapted to the size of the flexible metal foil sample;

[0059] S2, fixing the metal foil sample 7 onto the sintering platform;

[0060] S3, adjusting the parameters of the multi-degree-of-freedom direct writing robot 2, applying the sintered solder paste on the surface of the metal foil joint 8, and the coating amount of the first layer of solder paste is not enough to completely fill the metal foil joint area;

[0061] S4, using a layered gradient coating and sintering method, after applying solder paste to the metal foil joint 8 once, first open the protective gas device and the heating device in the heating platform 1, sinter the applied solder paste to remove organic components; then close the protective gas device and the heating device in the heating platform 1, and apply the sintered solder paste to the surface of the metal foil joint again to form contact with the previous layer of applied solder paste; open the protective gas device and the heating device in the heating platform 1 again, sinter the newly applied solder paste to remove organic components, and solidify the previous layer of applied solder paste;

[0062] S5. Cycle coating and sintering to form a gradient layered sintering structure, ensure that the organic matter in each layer of solder paste is completely volatilized, and solidify under high temperature to improve the connection strength of the sintered layer.

[0063] More specifically, in the above step S1, by controlling the movement of the metal rod corresponding to each ceramic heating plate 4, the ceramic heating plate 4 at the top end can be adjusted to form a shape suitable for the metal foil sintered sample as a whole, so that it can fit the flexible metal foil sintered sample, ensuring good heating effect within a small size, thereby obtaining a better heating effect.

[0064] The metal foil in the present invention can be a foil of metal or alloy materials such as silver, copper, aluminum, nickel, and steel.

[0065] In the above step S2, after the heating platform 1 is adjusted, the metal foil sample 7 needs to be fixed on the heating platform 1 to ensure that the metal foil sample 7 does not move, so as to avoid sample movement during solder paste coating and resulting in poor coating effect. For example, the sample can be fixed using devices such as pins.

[0066] The main parameters of the multi-degree-of-freedom direct writing robot 2 include moving path, direct writing pressure and moving speed; wherein, the moving path is determined by the geometric position of the joint on the metal foil surface, and the robot can plan the path along the joint path through the programming of the path function; the direct writing pressure is the air pressure in the needle tube 5, which is used to determine the amount of solder paste extruded per unit time; the moving speed is the moving speed of the needle 6. The three parameters are configured and programmed together to ensure the reliability and integrity of the sintering solder paste coating.

[0067] In the above step S3, the parameters of the multi-degree-of-freedom direct writing robot 2 are directly adjusted based on the size of the metal foil seam. If the depth-to-width ratio of the metal foil sample 7 is relatively small, the direct writing pressure needs to be increased and the direct writing speed needs to be reduced to ensure the extrusion of the solder paste; if the depth-to-width ratio of the metal foil sample 7 is relatively large, the direct writing pressure needs to be reduced and the direct writing speed needs to be increased to ensure the flow of the solder paste and improve the filling effect of the solder paste on the metal foil seam 8.

[0068] In the above step S3, after the parameters of the multi-degree-of-freedom direct writing robot 2 are adjusted, the path of the direct writing robot should match the path and distribution of the metal foil surface to achieve path overlap, thereby achieving a better coating effect.

[0069] Meanwhile, the sintered solder paste in step S3 is a nano-metal solder paste, which can be directly purchased on the market, such as silver, copper or composite metal solder paste, etc. The type of solder paste used must match the metal foil to be sintered, so as to obtain a better metallurgical bonding connection.

[0070] Furthermore, nano-metal solder paste is composed of nano-metal and organic dispersed adhesive. Nano-metal lowers the melting point of metal solder, thereby achieving low-temperature sintering interconnection, which not only protects the substrate and metal foil materials, but also ensures the excellent performance of sintered interconnection, and ultimately forms low-resistance and high-reliability metal foil patchwork interconnection.

[0071] In step S3, the coating amount of the first layer of solder paste is not enough to completely fill the metal foil seam area. That is, during the first coating, the solder paste should not 100% fill the metal foil seam area. The metal foil seam area needs to go through at least two coating processes before it is completely filled. Therefore, the number of cyclic coating and sintering is at least two times.

[0072] Furthermore, since there are organic substances as dispersants and binders in the sintered solder paste, the sintered solder paste needs to be preheated to remove the organic components. The sintering of the solder paste requires a curing and sintering process. Therefore, the present invention uses a layered gradient coating sintering method in step S4 to improve the quality of sintered interconnection.

[0073] In a specific embodiment, the layered gradient coating and sintering method of step S4 is: first, the metal foil joint 8 is coated with solder paste once, and the heating platform 1 is used to perform a solder paste dispersant removal and sintering process for 3-5 minutes on the first-coated solder paste; then, a second solder paste coating is performed, and the heating platform 1 is used again to perform a sintering process on the metal foil for 3-5 minutes, and the first-coated solder paste is cured and the dispersant organic matter in the second-coated solder paste is removed; the metal foil is subjected to a solder paste coating process three times, and heated again for 3-5 minutes, the first-coated solder paste is sintered, the second-coated solder paste is cured, and the organic component of the third-coated solder paste is removed, and this process is repeated to realize the gradient sintering process of different layers of solder paste.

[0074] In step S4, the number of cycles of the gradient sintering process is determined by the size of the metal foil. By increasing the number of cyclic coating and sintering times, the sintering effect of the solder paste can be improved. After the dispersant organic matter in each layer of the solder paste is volatilized, the sintering effect of the solder paste can be better guaranteed. After the two-stage heating of curing and sintering, the sintering interconnection strength can be improved.

[0075] During the gradient coating and sintering process of the present invention, the sintering time of the previous coating of the solder paste is inevitably longer than the sintering time of the subsequent coating of the solder paste, but this does not affect the sintering effect of the solder paste. On the contrary, the continuous high-temperature heating process is a continuous sintering effect on the solder paste, which can further reduce the porosity inside the sintered solder paste and improve the connection strength of the sintered solder paste.

[0076] In the present invention, the heating and sintering time of each layer of solder paste coating is at least 10 minutes to ensure the sintering effect.

[0077] In the present invention, the protective gas device needs to be turned on in each heating process, and the oxidation of the solder paste can be prevented by the protection of the argon environment; before each heating process starts, the protective gas device should work in advance for 3 to 5 seconds, and after each heating process ends, the protective gas device should continue to work for 15 to 20 seconds to ensure that the sintering environment is still an argon environment under the effect of residual temperature, thereby improving the performance and strength of the sintered interconnect material. The protective gas device is linked with the heating device in the heating platform 1 to avoid gas waste.

[0078] During the gradient coating and sintering process of the present invention, the fluidity of the sintered solder paste ensures the filling effect for the metal foil joint 8 and improves the filling density. For the subsequent secondary, tertiary... solder paste coating process, there is no need to consider the previously coated solder paste. Under the action of heating, after the dispersant in the solder paste is removed, the already coated solder paste will not flow.

[0079] The present invention uses a layered gradient coating sintering method, such as Figure 7 As shown, the strength and reliability of metal foil patchwork interconnection can be improved by stacking and repeating multiple steps.

[0080] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0081] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sintering device for interconnecting metal foil seams, characterized in that: include: The heating platform is composed of a plurality of single-degree-of-freedom ceramic heating sheet mechanisms arranged side by side, wherein the single-degree-of-freedom ceramic heating sheet mechanisms include a vertically arranged telescopic member and a ceramic heating sheet installed at the top end of the telescopic member; the plurality of telescopic members are controlled to move up and down at their respective top ends to deform the corresponding plurality of ceramic heating sheets as a whole into sintering platforms of different shapes, and the flexible metal foil sample is bonded and fixed on the sintering platform; the ceramic heating sheet is controlled to be opened and closed by the heating device; A multi-degree-of-freedom direct writing robot arm, with a direct writing needle mechanism installed at the end, can directly write and apply solder paste to the metal foil surface joints on the fixed metal foil sample by setting parameters of the multi-degree-of-freedom direct writing robot arm; A protective gas device is installed outside the single-degree-of-freedom ceramic heating plate mechanism and is used to spray sintering protective gas into the joint of the metal foil; A high-temperature thermal imager is installed outside the single-degree-of-freedom ceramic heating plate mechanism to observe the heat distribution on the surface of the metal foil sample during the sintering process.

2. A sintering device for interconnecting metal foil seams according to claim 1, characterized in that: Each of the ceramic heating plates is controlled by its own independent power supply; the size of the ceramic heating plates is determined by the metal foil sample. When the surface curvature of the metal foil sample is large, the size of the ceramic heating plates needs to be reduced to form a sintering platform with a larger curvature to match the metal foil sample.

3. A sintering device for interconnecting metal foil seams according to claim 1, characterized in that: The direct writing needle mechanism includes a needle tube capable of storing sintered solder paste and a needle head capable of flowing out sintered solder paste. The multi-degree-of-freedom direct writing robot arm needs to control the needle head to apply solder paste to the metal foil seam in a direction perpendicular to the tangent plane of the metal foil seam surface.

4. A sintering device for interconnecting metal foil seams according to claim 3, characterized in that: The robotic arm on the multi-degree-of-freedom direct-writing robotic arm is a 4-axis robotic arm.

5. A sintering method for metal foil patchwork interconnection, characterized in that: A sintering device for interconnecting metal foil seams according to any one of claims 1 to 4 is used, comprising the following steps: S1. Adjust the height of each ceramic heating plate in the heating platform so that the composed sintering platform is adapted to the size of the flexible metal foil sample; S2, fixing the metal foil sample onto the sintering platform; S3, adjusting the parameters of the multi-degree-of-freedom direct writing robot arm, applying the sintered solder paste on the surface of the metal foil joint, and the coating amount of the first layer of solder paste is such that the metal foil joint area is not completely filled; S4. Using a layered gradient coating and sintering method, after applying solder paste to the metal foil joints once, first open the protective gas device and the heating device in the heating platform to sinter the applied solder paste to remove organic components; then close the protective gas device and the heating device in the heating platform, and apply the sintered solder paste to the surface of the metal foil joints again to form contact with the previous layer of applied solder paste; open the protective gas device and the heating device in the heating platform again to sinter the newly applied solder paste to remove organic components, and solidify the previous layer of applied solder paste; S5. Cycle coating and sintering to form a gradient layered sintering structure.

6. A sintering method for metal foil seam interconnection according to claim 5, characterized in that: The sintered solder paste in step S3 is a nano-metal solder paste, which is composed of nano-metal and an organic dispersed adhesive.

7. A sintering method for metal foil seam interconnection according to claim 5, characterized in that: The parameters of the multi-degree-of-freedom direct writing robot arm include moving path, direct writing pressure and moving speed; wherein the moving path is determined by the geometric position of the seam on the metal foil surface, and the robot arm can perform path planning along the seam path through the programming of the path function; the direct writing pressure is the air pressure in the needle tube, which is used to determine the amount of solder paste extruded per unit time; the moving speed is the moving speed of the needle head; In step S3, the parameters of the multi-degree-of-freedom direct writing robot arm are directly adjusted based on the size of the metal foil seam. If the depth-to-width ratio of the metal foil sample is relatively small, the direct writing pressure needs to be increased and the direct writing speed needs to be reduced to ensure the extrusion of the solder paste; if the depth-to-width ratio of the metal foil sample is relatively large, the direct writing pressure needs to be reduced and the direct writing speed needs to be increased to ensure the flow of the solder paste.

8. A sintering method for metal foil seam interconnection according to claim 5, characterized in that: The number of cycles of the gradient sintering process is determined by the size of the metal foil.

9. A sintering method for metal foil seam interconnection according to claim 5, characterized in that: The heating and sintering time for each layer of solder paste is at least 10 minutes.

10. A sintering method for metal foil seam interconnection according to claim 5, characterized in that: The protective gas device is linked with the heating device in the heating platform; before each heating process starts, the protective gas device should work 3 to 5 seconds in advance, and after each heating process ends, the protective gas device should continue to work for 15 to 20 seconds.

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