Chip package structure without a card

Abstract

The application discloses a non-contact card chip packaging structure, comprising: a substrate comprising a first surface and a second surface; a chip mounted on the second surface of the substrate; a first metal layer arranged on the first surface of the substrate; and a second metal layer arranged on a side surface of the chip away from the substrate, wherein the first metal layer is electrically connected with the second metal layer, and a projection of the chip on the second surface of the substrate falls in the first metal layer. The application forms a shielding structure and a current limiting module in the packaging, thereby reducing the influence of the non-contact card in a strong electromagnetic induction environment.

Description

Technical Field

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

[0002] Contactless smart card chips (hereinafter referred to as "contactless chips") are core components in modern convenient payment, identity recognition, access control and other fields. They are widely used in various terminal products such as public transport cards, financial IC cards, campus cards, and NFC payment cards. Their stable operation is directly related to the user's daily experience and information security, and plays a key role in promoting the digitalization and intelligentization of society. With the continuous expansion of application scenarios for contactless chips, the challenges of complex electromagnetic environments they face throughout their entire life cycle are becoming increasingly prominent, becoming a major bottleneck restricting product reliability and service life.

[0003] In the production process of contactless SIM cards, from wafer dicing and chip packaging to module assembly, the operation of equipment and friction of materials in the workshop can easily generate sudden electrostatic fields. During the packaging and transportation stages, chips are usually stored in batches using carrier tapes, trays, etc. During handling and stacking, the accumulation of static electricity between different materials or external electromagnetic interference sources (such as electrical equipment of transportation vehicles) may cause local strong electromagnetic induction. In actual use scenarios, when users carry contactless SIM cards to enter and exit crowded places such as shopping malls and subway stations, electrostatic discharge in the surrounding environment and radiation from high-frequency electronic devices may create instantaneous strong electromagnetic environments.

[0004] When a contactless card chip is exposed to strong electromagnetic induction environments such as sudden electrostatic fields, the internal capacitor structure is the first to be affected. As a key component for storing charge and stabilizing circuit signals within the chip, the capacitor's dielectric layer experiences abnormal electron flow under strong electromagnetic induction. This can lead to minor issues like deterioration of the dielectric layer's insulation, causing capacitance drift and increased leakage current, resulting in decreased signal transmission stability and abnormal power consumption. In severe cases, it can cause direct breakdown of the dielectric layer, leading to capacitor failure and preventing the chip from performing core operations such as data reading / writing and encryption verification, resulting in a functional malfunction where the card "malfunctions."

[0005] More seriously, when the electromagnetic field in space changes drastically, the antenna (a core component for radio frequency signal interaction between the chip and external card readers), which is electrically connected to the contactless card chip, will generate a large coupling current due to electromagnetic induction. This large coupling current is transmitted to the chip's antenna end through the connection path between the antenna and the chip. On the one hand, this will cause a momentary overvoltage at the chip's antenna end, exceeding the withstand voltage threshold of the chip's internal circuitry. On the other hand, the excessive current will cause semiconductor junctions (such as the PN junctions of transistors within the chip) to break down, while simultaneously generating a large number of hot carriers. These hot carriers will not only damage the crystal structure of the semiconductor material but also cause a sudden rise in the local temperature of the chip, further exacerbating circuit performance degradation and even causing permanent chip damage. This significantly shortens the lifespan of the contactless card, causing inconvenience to users and increasing the after-sales maintenance costs and product iteration pressure for card manufacturers.

[0006] Currently, there are still shortcomings in the protection measures for contactless chips in strong electromagnetic induction environments, making it difficult to comprehensively address the electromagnetic damage problems in various scenarios and of various types. There is an urgent need to propose more efficient and reliable protection solutions. Utility Model Content

[0007] In view of the above problems, the purpose of this utility model is to provide a chip packaging structure for contactless cards, which reduces the impact of contactless cards on strong electromagnetic induction environments by forming a shielding structure and a current limiting module in the package.

[0008] According to one aspect of the present invention, a contactless chip packaging structure is provided, comprising: a substrate, including a first surface and a second surface opposite to each other; a chip, mounted on the second surface of the substrate; a first metal layer disposed on the first surface of the substrate; and a second metal layer disposed on the side surface of the chip away from the substrate, wherein the first metal layer and the second metal layer are electrically connected, and the projection of the chip on the second surface of the substrate falls into the first metal layer.

[0009] Optionally, the first metal layer is a continuous metal layer extending along a first surface of the substrate.

[0010] Optionally, the first metal layer extends into the substrate or penetrates the substrate.

[0011] Optionally, it further includes: two antenna pads extending through the substrate and electrically connected to two antenna pins of the chip via leads; an antenna located on the side surface of the substrate away from the chip, with a first end and a second end of the antenna respectively connected to the two antenna pads.

[0012] Optionally, it further includes a current limiting module, one end of which is connected to an antenna pin of the chip, and the other end of which is connected to an antenna pad.

[0013] Optionally, the current limiting module includes a reset fuse.

[0014] Optionally, it further includes: a molding compound that encapsulates the substrate, the chip, the antenna, the current limiting module, the first metal layer, and the second metal layer.

[0015] In the contactless chip packaging structure provided by this utility model, a chip is mounted on a first surface of a substrate, a first metal layer is formed on a second surface of the substrate corresponding to the chip, and a second metal layer is formed on the side of the chip away from the substrate. The first metal layer and the second metal layer are electrically connected by leads. Thus, when the environment in which the chip packaging structure is located encounters a sudden electrostatic field or other strong electromagnetic induction that causes the sudden strong electromagnetic induction field to pass through the chip, the first metal layer and the second metal layer can form a shielding protection layer to protect the chip and avoid chip failure caused by sudden strong electromagnetic induction.

[0016] Furthermore, the second surface of the substrate also includes two antenna pads. Of the two antenna pins of the chip, one antenna pin is electrically connected to one antenna pad, and the other antenna pin is electrically connected to the other antenna pad via a current limiting module. Thus, when the antenna generates a large coupling current due to a sudden strong electromagnetic induction, the current limiting module can limit the peak current between the antenna and the chip, avoiding instantaneous overvoltage due to the large coupling current of the antenna, thereby avoiding internal structural failure caused by the sudden strong electromagnetic induction. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the present invention with reference to the accompanying drawings, in which:

[0018] Figure 1 A schematic diagram of the chip packaging structure of a contactless card according to an embodiment of the present invention is shown;

[0019] Figure 2 A bottom view of the chip package structure of a contactless card according to a first embodiment of the present invention is shown.

[0020] Figure 3 A bottom view of the chip package structure of a contactless card according to a second embodiment of the present invention is shown. Detailed Implementation

[0021] Various embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0022] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0023] Figure 1 A schematic diagram of the chip packaging structure of a contactless card according to an embodiment of the present invention is shown; Figure 2 A bottom view of the chip package structure of a contactless card according to a first embodiment of the present invention is shown. Figure 3 A bottom view schematic diagram of the chip package structure of a contactless card according to a second embodiment of the present invention is shown. Figure 2 and Figure 3 For example, along Figure 1 The cross-sectional view obtained in the direction indicated by the dashed line AA.

[0024] like Figure 1 As shown, the chip package structure 100 of the contactless card of this application includes: a substrate 110, two antenna pads 111 and a first metal layer 112 located on the second surface of the substrate 110, a chip 120 located on the first surface of the substrate 110, a second metal layer 140 located on the side of the chip 120 away from the substrate 110, an antenna 130, a current limiting module 150 and a molding compound 170.

[0025] The substrate 110 provides mechanical support for the chip 120 and antenna 130 of the contactless card. The substrate 110 is typically made of polymer materials such as polyimide (PI) and epoxy resin, which possess excellent electrical insulation properties, mechanical strength, and thermal stability, meeting the requirements for contactless card use. Depending on the functional and performance requirements of the contactless card, the substrate 110 can be a single-layer, double-layer, or multi-layer structure. A multi-layer substrate 110 can achieve more complex circuit connections and signal transmissions through wiring and vias in the inner layers, improving the integration and performance of the contactless card.

[0026] Chip 120 is the core component of the contactless card, used for data storage, data processing, encryption operations, and communication functions. Chip 120 is fixedly connected to the first surface of substrate 110. Specifically, chip 120 and substrate 110 can be connected via an adhesive layer, and electrical connection between chip 120 and substrate 110 can be achieved via lead 160; alternatively, chip 120 and substrate 110 can be connected via a solder layer, in which case chip 120 is connected to substrate 110 in a flip-chip manner, and the solder layer achieves electrical connection between chip 120 and substrate 110. Chip 120 includes at least two antenna pins.

[0027] Antenna 130 can convert the electrical signals generated by chip 120 into electromagnetic waves for radiation, and can also receive electromagnetic waves from the reader / writer and convert them into electrical signals for transmission to chip 120. Antenna 130 is disposed on the second surface of substrate 110. Antenna 130 is typically made of multiple turns of fine metal wire. For example, some NFC antennas use a structure where fine metal wire is wound around a ferrite core to improve antenna performance. Some coil antennas also use etching processes to form metal coil patterns on materials such as polymer substrates. In this embodiment, antenna 130 is, for example, made of metal wire.

[0028] On the second surface of the substrate 110, two antenna pads 111 are provided. One antenna pad 111a is connected to one end of the antenna 130, and the other antenna pad 111b is connected to the other end of the antenna 130. Figure 2 or Figure 3 As shown. The antenna pad 111 extends a predetermined area along the second surface of the substrate 110, while also extending along the thickness direction of the substrate 110 (e.g., in the direction of thickness). Figure 1 On the third-party Z), the antenna pad 111 has a predetermined thickness or penetrates the substrate 110. In one embodiment, the antenna pad 111 penetrates the substrate 110, thereby exposing the cladding surface on a first surface of the substrate 110, so that the two antenna pads 111 can be electrically connected to the two antenna pins of the chip 120 respectively via leads.

[0029] Furthermore, a first metal layer 112 is disposed on the second surface of the substrate 110. The first metal layer 112 extends continuously along the second surface of the substrate 110, and has a predetermined thickness or penetrates the substrate 110 in the thickness direction of the substrate 110. Additionally, the projection of the chip 120 disposed on the first surface of the substrate 110 onto the second surface of the substrate 110 falls into the first metal layer 112. In one embodiment, if the first metal layer 112 penetrates the substrate 110, the chip 120 is fixed to the first metal layer 112 exposed on the first surface of the substrate 110 by an insulating adhesive layer.

[0030] A second metal layer 140 is formed on the surface of chip 120 away from substrate 110. The second metal layer 140 is formed, for example, by spraying. The second metal layer 140 is electrically connected to the first metal layer 112 via leads, so that when a sudden strong electromagnetic induction field passes through chip 120, the second metal layer 140 and the first metal layer 112 on the surface of chip 120 are connected by leads to form a shielding structure, which provides shielding protection for chip 120.

[0031] In addition, the package structure also includes a current limiting module 150, which limits the current between the antenna 130 and the chip 120. One end of the current limiting module 150 is electrically connected to an antenna pad 111 via a lead 160, and the other end is electrically connected to an antenna pin of the chip 120 via a lead 160. When the antenna 130 couples with a sudden strong electromagnetic induction, generating a large current, the current limiting module 150 limits the large current, thus protecting the chip 120 from damage by the large current. Specifically, those skilled in the art can adjust the peak current limited by the current limiting module 150 according to the specific type of the contactless card. In one embodiment, the current limiting module 150 includes a resettable fuse.

[0032] The molding compound 170 encapsulates the substrate 110, two antenna pads 111, a first metal layer 112, a chip 120, a second metal layer 140, an antenna 130, and a current limiting module 150, so that there are no exposed metal contacts on the surface of the package structure 100, while protecting the chip 120, antenna 130, etc. from physical damage, contamination, and corrosion.

[0033] In such Figure 2 In one embodiment shown, the projection of the antenna 130 onto the second surface of the substrate 110 is, for example, circling along the edge of the substrate 110. The first metal layer 112 and the two antenna pads 111 are located within the region of the antenna 130, and the projection of the antenna 130 onto the second surface of the substrate 110 does not overlap with the first metal layer 112 and the two antenna pads 111, except for the terminals connected to the two antenna pads 111. At least, the projection of the antenna 130 onto the second surface of the substrate 110 does not coincide with the first metal layer 111, thereby reducing the interference of the first metal layer 111 on the antenna 130 and improving the performance stability of the antenna.

[0034] In such Figure 3 In another embodiment shown, the second surface of the substrate 110 is divided into two regions. The projection of the antenna 130 onto the second surface of the substrate 110 falls into one region, while the other region contains the first metal layer 112 and two antenna pads 111. In this embodiment, the projection of the antenna 130 onto the second surface of the substrate 110 does not overlap with the first metal layer 112 and the two antenna pads 111, except for the terminals connected to the two antenna pads 111.

[0035] In other embodiments, in order to reduce the space occupied by the package structure 100, the projection of the antenna 130 on the second surface of the substrate 110 may be partially overlapped with the first metal layer 112 and the two antenna pads 111, but this will increase the risk of interference from the first metal layer 112 to the antenna.

[0036] In the contactless chip packaging structure provided by this utility model, a chip is mounted on a first surface of a substrate, a first metal layer is formed on a second surface of the substrate corresponding to the chip, and a second metal layer is formed on the side of the chip away from the substrate. The first metal layer and the second metal layer are electrically connected by leads. Thus, when the environment in which the chip packaging structure is located encounters a sudden electrostatic field or other strong electromagnetic induction that causes the sudden strong electromagnetic induction field to pass through the chip, the first metal layer and the second metal layer can form a shielding protection layer to protect the chip and avoid chip failure caused by sudden strong electromagnetic induction.

[0037] Furthermore, the second surface of the substrate also includes two antenna pads. Of the two antenna pins of the chip, one antenna pin is electrically connected to one antenna pad, and the other antenna pin is electrically connected to the other antenna pad via a current limiting module. Thus, when the antenna generates a large coupling current due to a sudden strong electromagnetic induction, the current limiting module can limit the peak current between the antenna and the chip, avoiding instantaneous overvoltage due to the large coupling current of the antenna, thereby avoiding internal structural failure caused by the sudden strong electromagnetic induction.

[0038] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to effectively utilize the present invention and its modifications. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A chip packaging structure for a contactless card, characterized in that, include: The substrate includes opposing first and second surfaces; The chip is mounted on the second surface of the substrate; A first metal layer is disposed on the first surface of the substrate; A second metal layer is disposed on the surface of the chip away from the substrate. The first metal layer is electrically connected to the second metal layer, and the projection of the chip onto the second surface of the substrate falls into the first metal layer.

2. The chip packaging structure according to claim 1, characterized in that, The first metal layer is a continuous metal layer extending along the first surface of the substrate.

3. The chip packaging structure according to claim 2, characterized in that, The first metal layer extends into the substrate or penetrates the substrate.

4. The chip packaging structure according to claim 1, characterized in that, Also includes: Two antenna pads extend through the substrate and are electrically connected to the two antenna pins of the chip via leads; An antenna is located on the side of the substrate away from the chip, and the first and second ends of the antenna are respectively connected to the two antenna pads.

5. The chip packaging structure according to claim 4, characterized in that, Also includes: A current limiting module, one end of which is connected to an antenna pin of the chip, and the other end of which is connected to an antenna pad.

6. The chip packaging structure according to claim 5, characterized in that, The current limiting module includes a reset fuse.

7. The chip packaging structure according to claim 5, characterized in that, Also includes: A molding compound that encapsulates the substrate, the chip, the antenna, the current limiting module, the first metal layer, and the second metal layer.

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