An integrated dual-interface tamper-resistant smart card and a method of manufacturing the same

Abstract

The application belongs to the technical field of smart card manufacturing, and particularly relates to an integrated double-interface tamper-resistant smart card and a manufacturing method thereof, which comprises a contact surface and a bottom circuit layer; the contact surface is formed with six independent contacts C1 to C6 through chemical etching; the bottom circuit layer is formed with a circuit pattern through chemical etching; the back surfaces of the contacts C1, C2, C3, C4 and C6 of the contact surface are provided with vertical conduction structures formed through a drilling copper sinking process. The application realizes vertical conduction between upper and lower layers through drilling copper sinking, avoids the problems of virtual welding and broken line that may occur in traditional jumper or pad connection, the ACF conductive adhesive has anisotropic conductive characteristics, improves signal integrity, simplifies the process, is suitable for large-scale production, saves the cumbersome procedures such as traditional welding and tin sheet pasting, reduces manual intervention, improves production consistency and yield, and the gluing process can be completed at low temperature.

Description

Technical Field

[0001] This invention belongs to the field of smart card manufacturing technology, specifically relating to an integrated dual-interface tamper-proof smart card and its manufacturing method. Background Technology

[0002] In existing technologies, dual-interface smart cards commonly employ processes such as wire picking, soldering, or conventional isotropic conductive adhesive to achieve electrical interconnection between contact and contactless circuits. These methods inherently have structural vulnerabilities. For example, the micron-sized metal leads used in the wire picking process are prone to breakage or poor soldering when the card is bent or under thermal stress. However, the soldering process has the risks of easy oxidation of solder joints, cracking after thermal fatigue, and short circuits caused by solder creep. Furthermore, if the alignment accuracy or pressure of ordinary conductive adhesive is insufficient, uneven distribution of conductive particles can easily occur, leading to excessively high contact resistance, signal attenuation, or current interference between adjacent contacts. These inherent defects in the process make the electrical connection of the card unstable for a long time. The reliability of signal transmission depends heavily on the assembly accuracy and the difficult-to-control material interface characteristics. Ultimately, this manifests as the card being prone to communication failure, data read / write errors, or even complete functional failure in complex usage environments such as temperature changes, mechanical vibration, or humid conditions. This severely restricts the application and service life of the product in fields with high reliability requirements such as finance and transportation. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides an integrated dual-interface anti-tamper smart card and its manufacturing method, aiming to solve the technical problems in the prior art where cards are prone to communication failures, data read / write errors, or even complete functional failures in complex usage environments.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an integrated dual-interface tamper-proof smart card and its manufacturing method, comprising a contact surface and a bottom circuit layer; both the contact surface and the bottom circuit layer are composed of copper foil and polyimide composite material; the contact surface forms six independent contacts C1 to C6 through chemical etching, the size and arrangement of which conform to the ISO7816 protocol; the bottom circuit layer forms a circuit pattern through chemical etching and is provided with solder points A1 and A2 for connecting an antenna; the back of contacts C1, C2, C3, C4, and C6 of the contact surface is provided with a vertical conductive structure formed by a drilling and copper plating process; the bottom circuit layer and the contact surface are bonded together with ACF conductive adhesive or anisotropic conductive adhesive to achieve electrical connection; the smart card is encapsulated with a contact PAD and the bottom circuit layer inverted, and the electrical connection cannot be restored after disassembly.

[0005] Furthermore, the bottom circuit layer can be used independently as a contactless communication module, or it can be combined with the contact surface to form a dual-interface module that supports both contact and contactless communication.

[0006] Furthermore, the electrical connection between the contact surface and the bottom circuit layer is achieved using ACF conductive adhesive or anisotropic conductive adhesive.

[0007] Furthermore, the inverted packaging structure ensures that the conductive adhesive connection structure is damaged and cannot be restored when the chip is disassembled without authorization.

[0008] Furthermore, the smart card is compatible with both the ISO7816 contact communication protocol and the contactless radio frequency communication protocol.

[0009] A method for manufacturing an integrated dual-interface tamper-proof smart card includes the following steps: S1. Connect the wafer pins on the bottom circuit layer with bonding wires and encapsulate them with encapsulating glue to form an 8-pin module. S2. Position the 8PIN module and the antenna together in the card body material, and form an integrated standard card body through a lamination process; S3. Mill a packaging groove on the standard card body that matches the shape of the contact surface; S4. The contact surfaces with etched contacts and drilled copper plating are bonded to the encapsulation groove using ACF conductive adhesive or anisotropic conductive adhesive to complete the assembly of the smart card.

[0010] Furthermore, the encapsulating adhesive described in step S1 covers the wafer and bonding wire areas for mechanical reinforcement and environmental protection.

[0011] Furthermore, in step S2, the lamination process uses a hot-pressing method to ensure that there are no air bubbles inside the card body and that the interlayer bonding is strong.

[0012] Furthermore, the depth of the encapsulation groove in step S3 is adapted to the thickness of the contact surface and the thickness of the adhesive layer to ensure the flatness of the fit and the structural strength.

[0013] Furthermore, step S4 employs an inverted encapsulation process to create an irreversible physical and electrical connection between the contact surface and the bottom circuit layer, thereby achieving tamper-proof functionality.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, a vertical conductive structure is formed on the back of the C1, C2, C3, C4, and C6 contacts on the contact surface using a drilling and copper plating process. Electrical and mechanical connections between the contact surface and the bottom circuit layer are then achieved using ACF conductive adhesive or anisotropic conductive adhesive. The drilling and copper plating process enables vertical conductivity between the upper and lower layers, avoiding issues such as cold solder joints and broken wires that may occur with traditional jumper or pad connections. ACF conductive adhesive, with its anisotropic conductivity, conducts only in the vertical direction while providing lateral insulation, preventing signal crosstalk and improving signal integrity. This simplifies the process, making it suitable for mass production. It eliminates cumbersome processes such as traditional soldering and solder sheet bonding, reducing manual intervention and improving production consistency and yield. Furthermore, the bonding process can be completed at low temperatures, avoiding damage to the PI material and chip from high temperatures. It also eliminates the need for additional vias or metal pillars, resulting in a thinner and lighter structure suitable for standard ISO card thickness designs and high-frequency, high-reliability applications such as financial cards and transportation cards.

[0015] 2. In this invention, the bottom circuit layer can be used independently as a contactless module, or it can be combined with the contact surface to form a dual-interface module. It is compatible with the ISO7816 contact protocol and the contactless radio frequency protocol, allowing users to choose contactless function only or dual-interface function as needed, reducing the number of cards to carry, improving ease of use, and is suitable for multi-scenario integration. Moreover, manufacturers can first mass-produce general contactless modules and then assemble the contact surface as needed, reducing inventory pressure and production costs. The modular design facilitates later function upgrades or repair and replacement.

[0016] 3. In this invention, the contact PAD and the bottom circuit layer are inverted and packaged, combined with ACF bonding process, to achieve an anti-tampering structure that fails upon disassembly. Once the card is illegally disassembled, the adhesive layer and conductive structure are destroyed, and the electrical connection is permanently lost and cannot be restored. This effectively prevents chip copying, data theft, or card counterfeiting. It is suitable for high-security scenarios such as bank cards and ID cards. The inverted packaging makes the internal structure difficult to disassemble without damage, increasing the difficulty of cracking and improving overall security. The bonding process achieves an irreversible connection, eliminating the need for additional anti-tampering sensors or complex circuits, reducing costs, and making it suitable for large-scale standardized production with good consistency in anti-tampering performance. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Please see Figure 1 This embodiment provides the following technical solution: it includes a contact surface and a bottom circuit layer; both the contact surface and the bottom circuit layer are composed of copper foil and polyimide composite material; the contact surface forms six independent contacts C1 to C6 through chemical etching, and their size and arrangement conform to the ISO7816 protocol; the bottom circuit layer forms a circuit pattern through chemical etching and is provided with A1 and A2 solder points for connecting the antenna; the back of the C1, C2, C3, C4, and C6 contacts of the contact surface is provided with a vertical conductive structure formed by a drilling and copper plating process; the bottom circuit layer and the contact surface are bonded together with ACF conductive adhesive or anisotropic conductive adhesive to achieve electrical connection; the smart card adopts an inverted encapsulation of the contact PAD and the bottom circuit layer, and the electrical connection cannot be restored after disassembly.

[0020] Specifically, this includes the contact surface and the bottom circuit layer; Both the contact surface and the bottom circuit layer use copper foil as the conductive layer and polyimide film as the insulating substrate, which are composited through a lamination process. Six independent electrical contacts, C1, C2, C3, C4, C5, and C6, are formed on the contact surface through a chemical etching process. The size, spacing, and planar arrangement of each contact strictly comply with the ISO7816 international standard protocol. A preset circuit pattern is formed on the bottom circuit layer through a chemical etching process. The pattern is specially designed with two solder points or pads, A1 and A2, for connecting the antenna coil required for contactless communication. On the contact surface, corresponding to the back positions of the five contacts C1, C2, C3, C4 and C6, a process of mechanical drilling followed by chemical copper plating is used to form vertical conductive through holes that penetrate the contact surface material, thereby achieving electrical conduction between the front and back of the contact. At the circuit nodes on the bottom circuit layer corresponding to the contacts C1, C2, C3, C4, and C6 mentioned above, anisotropic conductive adhesive film or anisotropic conductive adhesive is applied and then aligned and bonded to the back of the contact surface under hot pressing conditions, thereby achieving a stable and reliable electrical interconnection between the contact surface and the bottom circuit layer. The overall packaging structure of the smart card adopts a method of aligning and pressing the contact surface pad area and the bottom circuit layer module upside down. Once the packaging is completed, if it is illegally disassembled by external force, the conductive adhesive connection interface will be irreversibly physically damaged, resulting in permanent failure of the electrical connection, thereby achieving the physical anti-tampering function.

[0021] Preferably, by combining the following technical features, namely "the contact surface and the bottom circuit layer are composed of copper foil and polyimide material", "a vertical conductive structure formed by drilling and copper plating process is provided on the back of C1, C2, C3, C4, and C6 contacts", "electrical connection is achieved by ACF conductive adhesive or anisotropic conductive adhesive", and "contact PAD and bottom circuit layer are inverted packaged", the vertical conductive structure formed by drilling and copper plating and the ACF conductive adhesive are combined to achieve stable and reliable electrical interconnection, effectively avoiding the problems of poor soldering, broken wires and signal crosstalk in traditional processes; Secondly, the irreversible connection between the inverted packaging and the conductive adhesive ensures that the connection structure is permanently destroyed when the card is physically disassembled, thus achieving hardware-level anti-tampering functionality. Ultimately, the above structural design not only improved product reliability and safety but also laid the foundation for simplifying the subsequent assembly process.

[0022] The bottom wiring layer can be used independently as a contactless communication module, or it can be combined with the contact surface to form a dual-interface module that supports both contact and contactless communication.

[0023] Specifically, the bottom circuit layer and the chip and antenna connection point integrated on it constitute a complete contactless communication functional module. This module can be independently packaged and applied to smart cards that only require contactless functionality. Meanwhile, the bottom circuit layer module can also be combined and packaged with a contact surface with standard contacts to form a dual-interface smart card module that has both a contact interface and a contactless radio frequency interface, enabling one card to be used for two purposes.

[0024] Preferably, based on the bottom circuit layer structure, it can be used independently as a contactless communication module, or combined with the contact surface to form a dual-interface module, realizing the advantages of modular design. This design allows the same core module to be flexibly configured as a single contactless card or a dual-interface card, enhancing product line flexibility, reducing the types of components, helping to reduce production management and inventory costs, and enabling rapid response to market demands for different functional cards.

[0025] The electrical connection between the contact surface and the bottom circuit layer is achieved using ACF conductive adhesive or anisotropic conductive adhesive.

[0026] Specifically, the adhesive material used to achieve electrical connection between the contact surface and the bottom circuit layer is selected as anisotropic conductive film or anisotropic conductive adhesive. This material is conductive only in the direction perpendicular to the plane of the film. The conductive particles evenly distributed inside achieve the conduction of the upper and lower circuit nodes under pressure, while it remains insulating in the direction of the film plane, thereby effectively preventing short circuits between adjacent contacts or circuits with different potentials.

[0027] Preferably, the electrical connection between the contact surface and the bottom circuit layer is achieved by using ACF conductive adhesive or anisotropic conductive adhesive. Using ACF or anisotropic conductive adhesive for bonding results in a low process temperature, which can avoid damage to sensitive components caused by high temperature. Moreover, this process is easy to automate, which improves the consistency and reliability of the connection, while simplifying the production steps.

[0028] The inverted packaging structure means that the conductive adhesive connection structure is damaged and cannot be restored when the chip is disassembled without authorization.

[0029] Specifically, when the inverted packaging structure is subjected to unauthorized physical disassembly, the bonding interface of the anisotropic conductive adhesive or the non-isotropic conductive adhesive is mechanically peeled off or destroyed. As a result, the internal microparticle network or pathway used for conduction will break and cannot be restored by simple heavy pressure. This leads to a complete interruption of the electrical connection between the contact surface and the bottom circuit layer, and the card loses its function, thereby achieving the purpose of hardware-level anti-counterfeiting and anti-tampering.

[0030] Preferably, by clarifying the inverted packaging structure, the conductive adhesive connection structure is destroyed and cannot be restored when the chip is disassembled without authorization. The anti-tampering mechanism is embedded in the physical structure. Any illegal disassembly attempt will physically destroy the conductive adhesive layer and its internal electrical path, resulting in permanent functional failure. Thus, a high level of physical security protection can be achieved without relying on additional electronic detection circuits.

[0031] The smart card is compatible with both the ISO7816 contact communication protocol and the contactless radio frequency communication protocol.

[0032] Specifically, the smart card supports contact communication based on the ISO7816 protocol through standard contacts on its contact surface; at the same time, it supports contactless radio frequency communication based on standards such as ISO / IEC14443 through the antenna connected to the bottom circuit layer, thus achieving full compatibility of a single card with two mainstream communication protocols.

[0033] Preferably, by specifying that the smart card is compatible with both the ISO7816 contact communication protocol and the contactless radio frequency communication protocol, it ensures that the card can be seamlessly adapted to existing contact and contactless card reading devices, greatly expanding its application scenarios and providing users with the convenience of using one card for two purposes.

[0034] The manufacturing method of an integrated dual-interface tamper-proof smart card includes the following steps: S1, connecting wafer pins on the bottom circuit layer by wire bonding and encapsulating them with encapsulating adhesive to form an 8-pin module; S2, positioning the 8-pin module and antenna together in the card body material and forming an integrated standard card body through a lamination process; S3, milling an encapsulation groove on the standard card body that matches the shape of the contact surface; S4, bonding the contact surface with etched contacts and drilled copper plating to the encapsulation groove using ACF conductive adhesive or anisotropic conductive adhesive to complete the assembly of the smart card.

[0035] Specifically, on the bottom circuit layer with the completed circuit pattern, the pins of the integrated circuit wafer are connected to the corresponding pads of the circuit layer through wire bonding process. Then, epoxy resin and other encapsulating adhesives are used to encapsulate and protect the wafer, the bonding wires and the connection area, forming an integrated module with 8 external pins. The module made in the above steps and the preset non-contact antenna coil are precisely placed in the middle of the predetermined position of the multi-layer card body material. The layers of material are firmly bonded together by hot pressing lamination process to form a solid card blank that conforms to ISO thickness standards and has the module and antenna embedded inside. On the blank, a recessed encapsulation groove that matches the shape and size of the contact surface is machined using a precision milling machine in the area corresponding to the final installation contact surface. The contact surfaces, which have been pre-etched with contacts through chemical etching and have undergone drilling and copper plating, are coated or bonded with an anisotropic conductive film or apotropic conductive adhesive on their back or at the bottom of the encapsulation tank. They are then precisely aligned and placed into the encapsulation tank processed in the above steps. By applying a certain temperature and pressure, thermoforming is performed to firmly bond the contact surfaces to the tank and achieve electrical interconnection with the bottom circuit layer module, thus completing the assembly of the smart card.

[0036] Preferably, through a series of steps such as “forming an 8-pin module”, “laminating to form a standard card body”, “milling out the encapsulation groove”, and “bonding the contact surface with ACF conductive adhesive or anisotropic conductive adhesive”, this method modularizes and standardizes the production process. In particular, the process of laminating, milling grooves and then bonding ensures the overall structural strength and encapsulation accuracy of the card body, making efficient and high-yield mass production possible.

[0037] In step S1, the encapsulating adhesive covers the wafer and bonding wire areas for mechanical reinforcement and environmental protection.

[0038] Specifically, the encapsulating adhesive used completely covers and wraps the integrated circuit wafer and all bonding leads. After curing, it forms a protective layer. This protective layer serves a dual purpose: mechanical reinforcement to prevent lead breakage and environmental protection to prevent moisture and dust corrosion.

[0039] Preferably, by covering the wafer and bonding wire areas with encapsulating adhesive in step S1 for mechanical reinforcement and environmental protection, the reliability advantages in the process are highlighted. This dispensing and encapsulation step effectively protects the fragile wafer and bonding wire structure, enhances the mechanical strength of the module and its resistance to environmental factors such as humidity and dust, thereby improving the durability and long-term reliability of the final product.

[0040] In step S2, the lamination process uses hot pressing to ensure that there are no air bubbles inside the card and that the interlayer bonding is strong.

[0041] Specifically, the lamination process employs a hot-pressing method, performed under specific temperature, pressure, and time parameters to ensure a tight bond between the multi-layer card body materials and between them and the internal modules and antennas, eliminating internal air and forming a bubble-free, delamination-free, and densely structured integrated card body.

[0042] Preferably, the lamination process in step S2 uses hot pressing to ensure that there are no air bubbles inside the card body and that the interlayer bonding is strong. The hot pressing process can ensure that the materials of each layer are tightly and uniformly bonded, eliminate internal defects, and form a card body base with a high degree of integration and stable mechanical properties, which provides a guarantee for subsequent precision processing.

[0043] In step S3, the depth of the encapsulation groove is adapted to the thickness of the contact surface and the thickness of the adhesive layer to ensure the flatness of the fit and the structural strength.

[0044] Specifically, the processing depth of the encapsulation groove is precisely calculated and controlled. Its depth value is equal to the sum of the material thickness of the contact surface and the thickness of the conductive adhesive layer pre-set in step S4, thereby ensuring that the outer surface of the contact surface can remain flat with the surface of the card body after the contact surface is embedded, and that the internal adhesive layer is subjected to uniform pressure, so as to obtain the best bonding strength and electrical connection performance.

[0045] Preferably, by requiring the depth of the encapsulation groove in step S3 to be adapted to the thickness of the contact surface and the thickness of the adhesive layer, precise control of the groove depth is the key to achieving flat embedding of the contact surface and uniform thickness of the adhesive layer. This directly affects the stability of the electrical connection, the aesthetics of the product, and the overall structural strength.

[0046] Step S4 employs an inverted encapsulation process to create an irreversible physical and electrical connection between the contact surface and the bottom circuit layer, thereby achieving tamper-proof functionality.

[0047] Specifically, the hot-pressing process uses an inverted encapsulation method, that is, under pressure, the contact surface with contacts faces the inside of the card body and is directly aligned and pressed with the corresponding circuit area on the bottom circuit layer. This process causes the conductive adhesive to form an irreversible deformation and connection. Once cured, if forcibly separated, the connection interface will be destroyed, thus enabling the smart card manufactured by this method to have physical anti-tampering characteristics.

[0048] Preferably, by clearly defining step S4 and adopting the inverted encapsulation process, an irreversible physical and electrical connection is formed between the contact surface and the bottom circuit layer, thus solidifying the anti-tampering advantage at the method level. This process step ensures that an irreversible connection interface is built during the production process, making the anti-counterfeiting function an inherent attribute of the product.

[0049] Example 2: Please see Figure 1 In this embodiment, the staff used the technology disclosed in this invention in a city's public transportation system upgrade project; The project client requested the production of a dual-interface smart card that can be used for both contactless card swiping on subways and buses, and for contactless IC card top-up and transaction inquiries at designated convenience stores. Therefore, the card manufacturer adopted the integrated dual-interface tamper-proof smart card structure and manufacturing method described in this invention for production.

[0050] First, the manufacturer selects a 0.075 mm thick polyimide film as the substrate, and laminates 0.018 mm thick electrolytic copper foil onto its top and bottom surfaces to form the initial composite board. The contact surface uses a dedicated smart card chip from NXP, whose contact interface conforms to the ISO7816 standard. Six standard contact patterns, C1 to C6, are formed on the composite board using a precision chemical etching process. The etching solution is ferric chloride, and the linewidth accuracy is controlled within ±0.02 mm after etching. Subsequently, holes are drilled on the back of five critical contacts: C1 power contact, C2 reset contact, C3 clock contact, C4 programming power contact, and C6 ground contact, using a 0.15 mm diameter micro-drill. Then, a chemical copper plating process is performed inside the holes to deposit a dense copper layer approximately 0.025 mm thick, forming a reliable vertical through-hole.

[0051] The bottom circuit layer is manufactured using copper foil polyimide composite material of the same specifications. The precision circuit pattern connecting the chip pins and the non-contact antenna is formed through photolithography and etching processes. Two rectangular pads, A1 and A2, are designed at specific locations for soldering the 0.12 mm diameter enameled copper wire antenna. The antenna coil is wound into a 4-turn square structure that meets the requirements of ISO14443 Type A standard, with an inductance of approximately 3.5 microhenries.

[0052] On the bottom circuit layer, using K&S's automated wire bonding machine, the eight key pins of the NXP SmartMX2P60 series security chip are bonded to the corresponding eight pads on the bottom circuit layer with gold wires with a diameter of 0.025 mm. Then, Henkel's LOCTITEABLESTIK brand epoxy resin C810 is applied and cured at 150 degrees Celsius for 30 minutes to form a mechanically robust 8-pin module with environmental sealing protection.

[0053] Next, the module and the pre-wound antenna coil are precisely placed in the middle layer of multi-layer white PVC card material and sent into a laminator of model MSP300 from German company Müsa for hot pressing. The process parameters are set to 160 degrees Celsius, 15 MPa, and 30 minutes to obtain an integrated standard card blank with a thickness of 0.84 mm and a dense internal structure.

[0054] Then, using a precision CNC milling machine from Brother Industries of Japan, a rectangular encapsulation groove with a depth of 0.30 mm and dimensions precisely matching the contact surface is milled at a designated position on the front of the blank. In the final critical assembly stage, a layer of anisotropic conductive adhesive film, model ANISOLMAS040, manufactured by Sony Chemical Corporation, is pre-attached to the bottom of the groove. This film is 0.05 mm thick and contains uniformly dispersed gold-plated plastic conductive particles with a diameter of 5 micrometers. The contact surface, which has undergone drilling and copper plating, is placed face down, precisely aligned, and placed into the encapsulation groove. It is then sent to a thermopressor for final bonding under the following conditions: 180 degrees Celsius, 20 MPa pressure, and a holding time of 15 seconds.

[0055] Under these temperature and pressure conditions, the conductive particles in the ACF film are deformed by pressure, establishing an electrical path in the vertical direction from the bottom of the contact surface via to the corresponding pad of the bottom circuit layer. At the same time, the thermosetting resin cures to form a strong mechanical bond.

[0056] At this point, a complete dual-interface smart card has been manufactured. In actual use, when taking the subway, citizens only need to bring the card close to the card reader area of ​​the turnstile. The built-in antenna coil of the card senses energy and completes wireless communication with the contactless reader inside the turnstile at a frequency of 13.56MHz, enabling fast payment.

[0057] When citizens need to make large top-ups or check transaction details at convenience stores, they can insert their cards into the contact IC card reader / writer provided at the counter. The reader's six probes precisely contact the C1 to C6 contacts on the card. The electrical signal is reliably transmitted to the SmartMX2 chip at the bottom for processing through the vertical channels formed by drilling and copper plating and the Z-axis conductive path of the ACF adhesive, completing the secure transaction. More importantly, if criminals attempt to steal the card chip information, they can dissolve the card body material with chemical solvents or physically pry open the contact surface. The inverted packaging structure will force the ACF adhesive interface to undergo irreversible peeling and destruction, causing all vertical conductive paths to break instantly and permanently, and the chip's electrical connection to completely fail. This effectively prevents information theft and card counterfeiting, ensuring the security of citizens' card use and the financial security of the system. The entire embodiment demonstrates the entire process from raw material selection, precision processing, modular assembly to final functional implementation, verifying the comprehensive advantages of this invention in improving production efficiency, ensuring connection reliability, and enhancing physical security.

[0058] The working principle of this invention is as follows: Step 1: When a smart card is inserted into a contact card reader, the reader's probes make physical contact with the C1 to C6 electrical contacts on the card's contact surface, which conform to the ISO7816 standard. Electrical signals, such as power supply VCC, reset RST, clock CLK, and data I / O, are transmitted from the card reader through the corresponding contacts.

[0059] For contacts C1, C2, C3, C4, and C6 that need to connect to internal chips, the signal does not stop at the surface of the contact surface. Vertical conductive vias formed by drilling and copper plating on the back of these contacts guide the signal vertically downward from the contact surface, penetrating the contact substrate.

[0060] After the signal reaches the back of the contact surface through the through hole, it is immediately captured by the connection interface established below it by ACF, anisotropic conductive adhesive or non-isotropic conductive adhesive.

[0061] The conductive microparticles within the ACF adhesive form a conductive chain along the Z-axis, transmitting signals losslessly to the corresponding circuit nodes on the precisely aligned bottom wiring layer. Ultimately, the signals are transmitted via pre-etched precision lines on the bottom wiring layer to the corresponding pins of the core integrated circuit (chip) soldered or packaged at the bottom layer, completing the interaction between instructions and data.

[0062] Step 2: When the smart card enters the radio frequency field range of the contactless card reader, the electromagnetic waves emitted by the reader's antenna will couple to the antenna coil integrated inside the card.

[0063] The two ends of the antenna coil are soldered to dedicated A1 and A2 solder points on the bottom circuit layer. The induced AC signal and energy enter the circuit network of the bottom circuit layer directly through these two solder points. This circuit network is not only responsible for signal transmission, but its design also typically includes matching circuitry to optimize impedance matching between the antenna and the chip, maximizing energy transfer efficiency and communication distance.

[0064] The signal is then directed to the RF front-end pin of the same core chip. The chip demodulates the signal to obtain the instruction, processes it, and then sends the response signal back to the antenna coil through the circuit network. The antenna then transmits the modulated electromagnetic wave, which is received by the card reader, thus completing a contactless communication.

[0065] Step 3: The innovative structure of this smart card allows the bottom circuit layer, including the chip and antenna interface, to operate independently as a complete contactless communication module. This means that even without assembling the upper contact surface, the module itself already possesses complete contactless functionality.

[0066] When dual-interface functionality is required, the contact surface module and the bottom circuit layer module are physically and electrically integrated using the connection methods described in steps one and two above.

[0067] The chip automatically identifies the communication interface through its internal logic: when a contact is activated, it prioritizes or enables the contact communication protocol. When a radio frequency field is sensed, a contactless communication protocol is activated. Both share the same chip and storage area, achieving a high degree of functional integration and unified data management.

[0068] Step 4: The anti-tampering function is not implemented by software, but is embedded in the physical structure of the hardware. The inverted packaging method ensures that after final assembly, the ACF conductive adhesive connection interface between the contact surface and the bottom circuit layer is inside the card body and locked by the mechanical structure.

[0069] Any attempt to illegally disassemble the device, such as prying open the contact surface to directly access the chip or circuitry, will apply peeling or shear stress to the ACF adhesive layer. Since the curing bonding of the ACF adhesive and the formation of its internal conductive microparticle network are irreversible, this external force will cause the adhesive layer to tear and the conductive pathways to permanently break physically. As a result, even if the card is re-aligned and re-attached, the electrical connection cannot be restored, and the card immediately becomes unusable. This makes the physical intrusion itself the direct cause of functional failure, thus forming a robust hardware anti-counterfeiting and anti-tampering barrier.

[0070] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated dual-interface anti-tamper smart card, characterized in that, The device includes a contact surface and a bottom circuit layer. Both the contact surface and the bottom circuit layer are composed of a composite of copper foil and polyimide material. The contact surface is formed with six independent contacts, C1 to C6, through chemical etching, and their size and arrangement conform to the ISO7816 protocol. The bottom circuit layer is formed with circuit patterns through chemical etching and has A1 and A2 solder points for connecting the antenna. The back of the C1, C2, C3, C4, and C6 contacts on the contact surface has a vertical conductive structure formed by a copper plating process through drilling. The bottom circuit layer and the contact surface are bonded together with ACF conductive adhesive or anisotropic conductive adhesive to achieve electrical connection. The smart card is encapsulated with the contact PAD and the bottom circuit layer in an upside-down manner, and the electrical connection cannot be restored after disassembly.

2. The integrated dual-interface anti-tamper smart card according to claim 1, characterized in that: The bottom line layer can be used independently as a contactless communication module, or it can be combined with the contact surface to form a dual-interface module that supports both contact and contactless communication.

3. The integrated dual-interface anti-tamper smart card according to claim 1, characterized in that: The electrical connection between the contact surface and the bottom circuit layer is achieved using ACF conductive adhesive or anisotropic conductive adhesive.

4. The integrated dual-interface anti-tamper smart card according to claim 1, characterized in that: The inverted encapsulation structure ensures that the conductive adhesive connection structure is damaged and cannot be restored when the chip is disassembled without authorization.

5. The integrated dual-interface anti-tamper smart card according to claim 1, characterized in that: The smart card is compatible with both the ISO7816 contact communication protocol and the contactless radio frequency communication protocol.

6. A method for manufacturing an integrated dual-interface tamper-proof smart card, characterized in that, Includes the following steps: S1. Connect the wafer pins on the bottom circuit layer with bonding wires and encapsulate them with encapsulating glue to form an 8-pin module. S2. Position the 8PIN module and the antenna together in the card body material, and form an integrated standard card body through a lamination process; S3. Mill a packaging groove on the standard card body that matches the shape of the contact surface; S4. The contact surfaces with etched contacts and drilled copper plating are bonded to the encapsulation groove using ACF conductive adhesive or anisotropic conductive adhesive to complete the assembly of the smart card.

7. The manufacturing method of an integrated dual-interface anti-tamper smart card according to claim 6, characterized in that: In step S1, the encapsulating adhesive covers the wafer and bonding wire areas for mechanical reinforcement and environmental protection.

8. The manufacturing method of an integrated dual-interface anti-tamper smart card according to claim 6, characterized in that: In step S2, the lamination process uses hot pressing to ensure that there are no air bubbles inside the card body and that the interlayer bonding is strong.

9. The manufacturing method of an integrated dual-interface anti-tamper smart card according to claim 6, characterized in that: In step S3, the depth of the encapsulation groove is adapted to the thickness of the contact surface and the thickness of the adhesive layer to ensure the flatness of the fit and the structural strength.

10. A method for manufacturing an integrated dual-interface anti-tamper smart card according to claim 6, characterized in that: Step S4 employs an inverted encapsulation process to create an irreversible physical and electrical connection between the contact surface and the bottom circuit layer, thereby achieving tamper-proof functionality.

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