Smart card csp module structure and smart card

Abstract

The utility model discloses a kind of intelligent card CSP module structure and intelligent card, the module structure aims at solving the problem of complex, low reliability of traditional intelligent card module structure. The module includes substrate, integrated circuit chip, multi-turn coil, conductive blind hole and external contact pad. Chip is directly bonded on the upper surface of substrate by fan-out and flip-chip bonding process. Coil is integrated on the upper surface of substrate and surrounds chip. The utility model is characterized in that, the second radio frequency solder ball of chip and the second terminal of coil are connected to the same spare external contact pad on the lower surface of substrate through the conductive blind hole inside substrate, thereby simply forming the radio frequency loop of near field communication, and the antenna wire bonding process is saved. The module structure is compact, reliable connection, especially suitable for high thickness and reliability requirements of intelligent card product.

Description

Technical Field

[0001] This utility model relates to the field of chip packaging technology, and in particular to a smart card CSP module structure and a smart card. Background Technology

[0002] In the manufacturing of dual-interface smart cards (supporting both contact and contactless communication), the following process is typically employed: first, the module carrying the chip (small card) is packaged, and then it is electrically connected to the pre-fabricated antenna coil on the card body (large card) conforming to the ISO / IEC 7810 ID-1 standard (approximately 85.6mm x 54mm) via a soldering process. This soldering step increases the complexity and cost of the card manufacturing process, and the solder joints are susceptible to reliability risks such as poor soldering and oxidation. The purpose of this invention is to provide a highly integrated modular structure that incorporates a small-sized antenna coil within the module, which couples with a large-sized card body antenna coil embedded on the card body to form a composite antenna system. This allows the connection between the chip and the antenna to be completed during the module packaging stage, completely eliminating the subsequent step of soldering the smart card module to the antenna coil on the card body, simplifying the overall card manufacturing process, and improving product reliability.

[0003] Furthermore, traditional chip mounting methods limit further miniaturization and thinning of modules. Therefore, there is an urgent need for an integrated smart card module structure that is simpler in structure, more reliable, and thinner. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a smart card CSP module structure and smart card that is compact, requires no wiring, and has high reliability.

[0005] To achieve the first aspect of the above objectives, the present invention adopts the following technical solution: A smart card CSP module structure, comprising: substrate; An integrated circuit chip has a redistribution layer formed on its active surface. The redistribution layer fans out and redistributes the original pads of the chip, and forms solder balls at the fan-out ends. The integrated circuit chip is directly bonded to the upper surface of the substrate by means of the solder balls using a flip-chip bonding method. A multi-turn coil is integrated on the upper surface of the substrate and surrounds the periphery of the integrated circuit chip. The coil has a first terminal located in its central region and a second terminal located in its edge region. Multiple conductive blind vias penetrate the substrate; and Multiple external contact pads are disposed on the lower surface of the substrate in an insulated manner from each other; in, The solder ball includes a first radio frequency solder ball, which is directly electrically connected to the first terminal of the coil via a wire on the substrate. The solder ball also includes a second radio frequency solder ball, which is connected to a first conductive region on the lower surface of the substrate through at least one first conductive blind via. The second terminal of the coil is also connected to the same first conductive region through at least one second conductive blind hole; The multiple input / output signal solder balls in the solder ball are independently connected to other external contact pads on the lower surface of the substrate through corresponding conductive blind holes.

[0006] Multiple external contact pads are disposed on the lower surface of the substrate in an insulated manner, forming a contact surface conforming to the ISO / IEC 7816 standard.

[0007] Furthermore, the first conductive area is a functional spare pad, which is used within the module solely to achieve the electrical connection between the second RF solder ball and the second terminal of the coil.

[0008] Furthermore, the multi-turn coil is a planar helical wire formed by etching or printing.

[0009] Furthermore, an underfill adhesive is filled between the integrated circuit chip and the upper surface of the substrate, and a molding compound is formed on the back of the chip.

[0010] Furthermore, the bottom filler and the encapsulating layer are made of epoxy resin.

[0011] Furthermore, the overall shape of the module is rectangular, and its size matches the layout of the external contact pads, making it suitable for ID-1 type smart cards.

[0012] To achieve the second aspect of the aforementioned objective, the present invention adopts the following technical solution: A smart card, comprising: The card body contains an embedded first antenna coil; The smart card CSP module structure described above is embedded and fixed in a preset card slot on the card body; The exposed external contact pads of the module structure constitute the metal contacts of the smart card, and the multi-turn coil integrated inside the module structure constitutes the second antenna coil. The first antenna coil and the second antenna coil are placed opposite each other in space and are electromagnetically coupled to form a composite antenna system.

[0013] The beneficial effects of this utility model are as follows: 1. High integration and compact structure: By fabricating the antenna coil directly on the substrate and integrating it with the chip using fan-out and flip-chip bonding, the additional antenna bonding steps are eliminated, which significantly simplifies the module structure and reduces the module thickness.

[0014] 2. High reliability: The use of flip-chip bonding and underfill provides a stronger mechanical connection and better thermal performance than traditional wire bonding, making the module more resistant to bending and physical stress during smart card use.

[0015] 3. Excellent electrical performance: The chip and substrate are directly connected via solder balls, resulting in a short path and low parasitic parameters, which is beneficial for improving the quality of RF signal transmission. The RF loop connection is achieved through a single spare pad, a clever design that saves board space.

[0016] 4. Good process compatibility: This structure makes full use of mature fan-out packaging and surface mount technology, which makes it easy to achieve large-scale and automated production with controllable costs. Attached Figure Description

[0017] Figure 1 This is a top view of the smart card module structure of this utility model (the encapsulation body is omitted). Figure 2 This is a cross-sectional schematic diagram of the smart card module structure of this utility model; Figure 3 This is a schematic diagram of the layout of the lower surface (contact surface) of the substrate of this utility model; Figure 4 This is a schematic diagram of the dual-coil coupling structure of the smart card of this utility model.

[0018] Explanation of the labels in the diagram: 10-Substrate; 11-Upper surface; 12-Lower surface; 20-Integrated circuit chip; 21-Redistribution layer; 22-Solder ball; 221-First RF solder ball; 222-Second RF solder ball; 223-Input / output signal solder ball; 30-Multi-turn coil; 31-First terminal; 32-Second terminal; 40-Conductive blind via; 41-First conductive blind via; 42-Second conductive blind via; 50-External contact pad; 51-Spare external contact pad; 60-Molded encapsulation layer; 100-Card body; 200-Module structure; 300-Card body antenna coil. Detailed Implementation

[0019] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0020] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0021] Example 1 like Figures 1 to 3 As shown, the smart card CSP module structure provided in this embodiment mainly includes a substrate 10, an integrated circuit chip 20, a multi-turn coil 30, a conductive blind hole 40, and an external contact pad 50.

[0022] The substrate 10 can be made of conventional circuit board materials such as FR-4 or polyimide. The upper surface 11 of the substrate 10 is formed with a multi-turn coil 30 and necessary connecting wires through processes such as photolithography and etching. The coil 30 is planar spiral and is arranged in the edge area of ​​the substrate 10, with the first terminal 31 in the middle and the second terminal 32 at the edge.

[0023] The integrated circuit chip 20 is pre-fan-out packaged, with a redistribution layer 21 and solder balls 22 fabricated on its active surface. The chip 20 is mounted in the central region of the upper surface 11 of the substrate 10 using a flip-chip bonding method. The solder balls 22 on the chip are electrically and mechanically connected to the corresponding pads on the upper surface 11 of the substrate 10 via a reflow soldering process. The solder balls 22 include a first RF solder ball 221 and a second RF solder ball 222 for RF signals, and multiple input / output signal solder balls 223 for power, ground, and data.

[0024] The first RF solder ball 221 passes through a metal wire on the upper surface 11 of the substrate 10 (see...). Figure 1The second RF solder ball 222 is directly connected to the first terminal 31 of the coil 30. The second RF solder ball 222 is connected to a spare external contact pad 51 on the lower surface 12 of the substrate 10 through one or more (one in the example) first conductive blind vias 41. Simultaneously, the second terminal 32 of the coil 30 is also connected to the same spare external contact pad 51 through one or more (one in the example) second conductive blind vias 42. Thus, the second RF solder ball 222 and the second terminal 32 of the coil 30 are electrically connected by sharing the spare external contact pad 51, forming a complete NFC antenna loop. Other input / output signal solder balls 223 are connected to corresponding external contact pads 50 (such as VCC, GND, I / O, etc.) on the lower surface 12, conforming to the ISO 7816 standard, through their respective conductive blind vias 40. This spare external contact pad exists as an external contact pad in the module, but its function is not defined internally; it is only used as an internal bridging point between the second RF path and the antenna coil.

[0025] To enhance reliability, an epoxy resin underfill (not shown) is filled between the chip 20 and the substrate 10. Finally, the entire upper surface of the substrate 10 and the back of the chip 20 are encapsulated with epoxy molding compound to form an encapsulation layer 60, completing the module manufacturing process.

[0026] The module is typically rectangular in shape, and its dimensions are designed to meet the specifications of the ID-1 type smart card module so that it can be embedded in a standard-sized smart card body. Those skilled in the art will understand that the ID-1 type module is a standard component used on cards conforming to the ISO / IEC 7810 standard and measuring 85.60mm × 53.98mm (such as bank cards and ID cards).

[0027] Example 2 See Figure 4 This embodiment presents a high-performance or compatible smart card conforming to the ISO / IEC 7810 standard. The smart card includes a card body 100 and a module structure 200 (the smart card CSP module structure of Embodiment 1). A large-sized card body antenna coil 300 (first antenna coil) is embedded within the card body 100 during manufacturing. When the module structure 200, which integrates the built-in coil 30 (second antenna coil), is embedded in the card body, the two coils overlap or are placed adjacent to each other in space. Due to electromagnetic induction, the coil 30 built into the module electromagnetically couples with the card body antenna coil 300, together forming a composite antenna system with a larger effective area or superior performance. This design can be compatible with traditional card manufacturing processes that rely on card body antennas, or improve the distance and stability of contactless communication by utilizing a larger card body antenna.

[0028] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A smart card CSP module structure, characterized in that, include: substrate; An integrated circuit chip has a redistribution layer formed on its active surface. The redistribution layer fans out and redistributes the original pads of the chip, and forms solder balls at the fan-out ends. The integrated circuit chip is directly bonded to the upper surface of the substrate by the solder balls using a flip-chip bonding method. A multi-turn coil is integrated on the upper surface of the substrate and surrounds the periphery of the integrated circuit chip. The coil has a first terminal located in its central region and a second terminal located in its edge region. Multiple conductive blind vias penetrate the substrate; as well as Multiple external contact pads are disposed on the lower surface of the substrate in an insulated manner from each other; in, The solder ball includes a first radio frequency solder ball, which is directly electrically connected to the first terminal of the coil via a wire on the substrate. The solder ball also includes a second radio frequency solder ball, which is connected to a first conductive region on the lower surface of the substrate through at least one first conductive blind via. The second terminal of the coil is also connected to the same first conductive region through at least one second conductive blind hole; The multiple input / output signal solder balls in the solder ball are independently connected to other external contact pads on the lower surface of the substrate through corresponding conductive blind holes.

2. The smart card CSP module structure according to claim 1, characterized in that, The first conductive area is a functional spare pad, which is used within the module only to realize the electrical connection between the second RF solder ball and the second terminal of the coil.

3. The smart card CSP module structure according to claim 1, characterized in that, The multi-turn coil is a planar helical wire formed by etching or printing.

4. The smart card CSP module structure according to claim 1, characterized in that, An underfill adhesive is filled between the integrated circuit chip and the upper surface of the substrate, and a plastic encapsulation layer is formed on the back of the chip.

5. The smart card CSP module structure according to claim 4, characterized in that, The bottom filler and encapsulation layer are made of epoxy resin.

6. The smart card CSP module structure according to claim 1, characterized in that, The module has a rectangular shape, and its size matches the layout of the external contact pads, making it suitable for ID-1 type smart cards.

7. The smart card CSP module structure according to claim 1, characterized in that, The substrate is a circuit board made of FR-4 or polyimide material.

8. A smart card, characterized in that, include: Card body, wherein a first antenna coil is embedded in the card body; The smart card CSP module structure as described in any one of claims 1 to 7, wherein the module structure is embedded and fixed in a preset card slot on the card body; The exposed external contact pads of the module structure constitute the metal contacts of the smart card, and the multi-turn coil integrated inside the module structure constitutes the second antenna coil. The first antenna coil and the second antenna coil are placed opposite each other in space and are electromagnetically coupled to form a composite antenna system.

Images