RFID chip and RFID chip anti-transfer method
By setting up corrosion-free insulating material capacitors on the RFID chip and identifying chip transfer by changing the capacitance value, the problem of RFID tag being removed and reused is solved, and the security of the anti-counterfeiting tag is improved.
Patent Information
- Application Number
- CN202410045313.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-11
- Publication Date
- 2025-07-11
AI Technical Summary
Existing RFID anti-counterfeiting tags are easily removed and reused, resulting in the inability to identify whether the tag has been transferred, increasing the difficulty of counterfeiting.
A capacitor of insulating material that is easily corrosive is set on the RFID chip. By measuring the change in the capacitance value, it is used to identify whether the chip is transferred, and the characteristics that are difficult to recover after cleaning of the capacitor medium.
Effectively identify whether the chip is transferred, prevent counterfeiters from achieving the purpose of fakes and realism by manufacturing capacitors with the same parameters, and improve the security of RFID anti-counterfeiting tags.
Smart Images
Figure CN120297307A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of RFID (Radio Frequency Identification) anti-counterfeiting, and particularly to an RFID chip and an RFID chip anti-transfer method. Background Art
[0002] RFID anti-counterfeiting tags have been widely used in products such as wines, jewels, and cosmetics. These products have high added value and huge demand, and the counterfeiting problem is very serious. By using the uniqueness of RFID tags to record commodity information, anti-counterfeiting tracking can be realized, and counterfeiters are prevented from imitating for profit-making. For early RFID tags, the substrates of antennas or external wires mostly used fragile materials. When the commodity packaging or wine bottle cap is opened, it is easy to cause antenna damage, resulting in inability to read information; or the external wire is torn off, and the chip recognizes that the tag is damaged, then it is judged that the commodity has been opened. Driven by interests, counterfeiters can, under off-site conditions, remove the genuine tag chip from the genuine commodity and reinstall it on a tag with a complete antenna and external wire. In this case, the chip cannot determine whether the tag has been opened. To increase the difficulty of counterfeiting, RFID anti-counterfeiting tags have added external characteristic devices such as resistors, capacitors, and inductors. When the tag is torn, the external characteristic devices are torn off at the same time. Counterfeiters need to completely transfer the external characteristic devices or manufacture external characteristic devices with the same or similar parameters.
[0003] Currently, there are mainly two solutions in the industry for passive RFID anti-counterfeiting, both of which are for the situation where RFID tags are transferred. One solution is that the chip detects the connection state of the external wire. This wire material generally uses a fragile material. After the fragile material is torn off, the chip detects that the external wire is disconnected and judges that the RFID tag has been transferred; however, counterfeiters can reconnect the external wire when the chip is off-site and out of power, so that the chip cannot recognize that the tag has been transferred. Another solution is that the chip detects external devices such as capacitors, resistors, or inductors. During the transfer of the tag, the parameters of the external devices may change. When the chip detects that these changes exceed a certain range, it judges that the tag has been transferred. This detection solution increases the difficulty of tag transfer to a certain extent, but counterfeiters can still remove the chip and external devices together, or manufacture devices with similar characteristics, and then package them on a new package, so that the chip cannot recognize that the tag has been transferred. Summary of the Invention
[0004] Embodiments of the present invention provide an RFID chip and an RFID chip anti-transfer method for an RFID anti-counterfeiting tag, which can solve the situation where RFID anti-counterfeiting tags are reused from the source and ensure the security of RFID anti-counterfeiting tags in applications.
[0005] To this end, the embodiments of the present invention provide the following technical solutions:
[0006] On the one hand, the embodiments of the present invention provide an RFID chip, the RFID chip includes: a chip body, a capacitor is arranged on the chip body, the capacitor medium is an easily corroded insulating material, and the capacitor is used to prevent the chip from being transferred.
[0007] Optionally, the capacitor is arranged on the passivation layer of the chip body.
[0008] Optionally, the capacitor is an interdigital capacitor, and the capacitor medium is filled in the gap of the interdigital capacitor.
[0009] Optionally, the shape of the interdigital capacitor is a regular shape or an irregular shape.
[0010] Optionally, the layer to which the capacitor medium belongs is the top layer or the sub-top layer of the chip.
[0011] Optionally, the capacitor is a parallel plate capacitor, and the capacitor medium is filled between the upper plate and the lower plate of the parallel plate capacitor.
[0012] Optionally, one or more holes are arranged on the upper plate.
[0013] Optionally, the capacitor medium is filled during the wafer processing.
[0014] Optionally, a layered wire board is arranged on the surface of the chip, one end of the capacitor is connected to the wire board, and the other end of the capacitor is a pin or an internal node of the chip.
[0015] On the other hand, the embodiments of the present invention further provide an RFID chip anti-transfer method, the RFID chip includes an RFID chip; the method includes:
[0016] During the working process of the RFID chip, measure the capacitance in the RFID chip to obtain a measurement value;
[0017] Obtain the nominal value of the capacitor pre-stored, and the nominal value is measured after the RFID chip is manufactured;
[0018] Calculate the difference between the measurement value and the nominal value;
[0019] If the difference is less than a set error threshold, determine that the RFID chip is normal; otherwise, determine that the RFID chip has been transferred.
[0020] The RFID chip provided by the embodiment of the present invention is provided with a capacitor on the chip body to prevent the chip from being transferred, and the capacitor dielectric is made of an easily corroded insulating material. When a forger peels the chip from the RFID tag and washes the chip surface with a reagent, the capacitor dielectric is easily removed, resulting in a change in the capacitance value of the capacitor, and thus it is very easy to identify that the RFID tag has been transferred.
[0021] Furthermore, since the capacitor dielectric is filled in during the wafer processing stage and new dielectric cannot be filled in after cutting into chips, it has the characteristic of being irreparable. According to the change in the capacitance value, it is convenient to determine that the chip has been transferred.
[0022] Furthermore, one end of the capacitor on the passivation layer of the chip body is inside the chip or a pin without bumps, which can prevent forgers from achieving the purpose of passing off the fake as genuine by manufacturing capacitors with the same capacitance value after transferring the chip.
[0023] Furthermore, during the process of chip transfer, the conductive adhesive and capacitor dielectric on the chip surface are easily washed off by the reagent. Since the gap of the interdigital capacitor is very small, when re-coating the conductive adhesive for inverted installation, conductive particles are easily generated during the pressing process of the conductive adhesive, causing a short circuit between both ends of the interdigital capacitor, and thus it can also be identified that the chip has been transferred.
[0024] The RFID chip anti-transfer method provided by the embodiment of the present invention utilizes the structural characteristics of the above RFID chip. After the RFID chip is manufactured, the nominal value of the capacitor on the RFID chip is measured. Correspondingly, during the operation of the RFID chip, the capacitor on the RFID chip is measured to obtain a measured value; according to the measured value, the nominal value, and the set error threshold, it is convenient to determine whether the RFID chip has been transferred. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 is a schematic structural diagram of the RFID chip provided by the embodiment of the present invention;
[0026] Figure 2 is a schematic structural diagram of the interdigital capacitor in the RFID chip provided by the embodiment of the present invention;
[0027] Figure 3 is Figure 2 a longitudinal sectional view of the interdigital capacitor in
[0028] Figure 4 is a schematic structural diagram of the RFID chip provided by the embodiment of the present invention;
[0029] Figure 5 is Figure 4 a longitudinal sectional view of the planar structure capacitor in
[0030] Figure 6 It is a schematic structural diagram of a planar capacitor in the RFID chip module provided by an embodiment of the present invention;
[0031] Figure 7 It is a flowchart of a method for preventing RFID chip transfer provided by an embodiment of the present invention;
[0032] Figure 8 It is a schematic diagram of the principle of capacitance measurement. Specific embodiments
[0033] The principles and spirit of the present invention will be described below with reference to the exemplary embodiments shown in the accompanying drawings. It should be understood that the description of these embodiments is only for enabling those skilled in the art to better understand and then implement the present invention, rather than limiting the scope of the present invention in any way.
[0034] Aiming at the problems existing in the solutions for preventing RFID tags from being transferred in the prior art, an embodiment of the present invention provides an RFID chip, which is used for an RFID tag. As Figure 1 shown, the RFID chip includes a chip body 10, and a capacitor 11 is arranged on the chip body 10. The capacitor medium is an easily corroded insulating material, and the capacitor 11 is used to prevent the chip from being transferred.
[0035] When a forger uses a reagent (such as an acidic or alkaline solution for removing conductive glue) to clean the conductive glue on the surface of the chip, the capacitor medium is easily washed away, causing the capacitance value of the detected capacitor to change. Therefore, it is very easy to identify that the RFID tag has been transferred.
[0036] In specific applications, the capacitor 11 can have various structures and implementation methods, such as interdigital capacitors or planar capacitors. Examples are given below.
[0037] As Figure 2 shown, it is a schematic structural diagram of an interdigital capacitor in the RFID chip provided by an embodiment of the present invention. Figure 3 It is Figure 2 a longitudinal sectional view of the interdigital capacitor in
[0038] At the same time, referring to Figure 2 and Figure 3 , in this embodiment, the capacitor 11 is an interdigital capacitor arranged on the passivation layer of the chip body. The gap of the interdigital capacitor is filled with an insulating medium 1, and the insulating medium 1 is the capacitor medium. The layer to which the capacitor medium belongs can be the top layer or the sub-top layer of the chip. For example, an insulating layer made of other easily corroded materials can be coated on the layer to which the capacitor medium belongs. The insulating medium 1 can be, for example, but not limited to, materials such as polyimide.
[0039] The two terminals of the interdigital capacitor are CAPP and CAPN respectively. During the wafer processing, the insulating medium 1 can be filled into the gap of the interdigital capacitor.
[0040] The calculation formula of the capacitance value of the capacitor is as follows:
[0041]
[0042] Among them, A is the area of the capacitor, ε s is the relative dielectric constant of the capacitor medium, ε0 is the relative dielectric constant of vacuum, and d is the distance between the two plates of the capacitor.
[0043] The distance between adjacent fingers of the interdigital capacitor is d1, and the distance between the finger tip of one finger and the common end of another finger is d2. The capacitance value of the interdigital capacitor is mainly determined by the following two aspects: 1) the electric field contribution of region ①; 2) the capacitance value of the sidewall capacitor generated in region ②.
[0044] Since the distance in region ① is very small, only the insulating medium 1 can be filled during the wafer processing. After the chip is cut into chips, the capacitance value of the interdigital capacitor has been determined. Once the forger removes the insulating medium 1 on the chip surface and reinstalls it upside down on the forged product, on the one hand, the insulating material in region ① is removed and becomes air. Even if the forger reapplies a similar insulating material on the chip surface, region ① cannot be filled, so the capacitance value of the interdigital capacitor will change, and it is easy to detect that the chip has been transferred; on the other hand, when the chip is transferred and reinstalled upside down with conductive adhesive, due to the very small gap between adjacent fingers of the interdigital capacitor, conductive particles are easily generated during the pressing process of the conductive adhesive, causing a short circuit between the two ends of the interdigital capacitor, so that the transfer of the chip can also be identified.
[0045] In a specific application, the shape of the interdigital capacitor can be a regular shape, such as but not limited to: ring shape, straight shape, curved shape, etc.; it can also be an irregular arbitrary shape, and the embodiments of the present invention do not make any limitations in this regard.
[0046] Generally, after the forger removes the chip, it can be directly coated with conductive adhesive and reinstalled upside down. In view of this situation, in another non-limiting embodiment, a wire board can also be covered on the chip surface and connected to one end of one finger of the interdigital capacitor, so as to form a flat structure capacitor with another finger. Correspondingly, the other end of the interdigital capacitor is a pin or an internal node of the chip, and the embodiments of the present invention do not make any limitations in this regard.
[0047] As Figure 4 shown, it is another schematic structural diagram of the wire board in the RFID chip provided by the embodiment of the present invention, Figure 5 showing Figure 4 the longitudinal sectional schematic diagram of the flat structure capacitor in
[0048] Referring to Figure 4 and Figure 5 as well, in this embodiment, one end of the interdigital capacitor is connected to the laminated wire board 12. As Figure 4 shown, the wire board 12 is connected to the CAPN end of the interdigital capacitor, and the metal connected to CAPP on the chip forms a planar structure capacitor.
[0049] In specific applications, as Figure 5 shown, the wire board 12 can be arranged in the RFID tag, and a medium 2 is filled between the medium 1 and the wire board 12, where the medium 1 is a capacitive gap insulating material and the medium 2 is a conductive adhesive material.
[0050] When a forger removes the RFID chip and directly coats the surface of the chip with a conductive adhesive and installs it on a new tag, the thickness of the medium 2 increases, the distance d3 of the planar structure capacitor changes, and the capacitance value changes, so it can be determined that the chip has been transferred.
[0051] In another non-limiting embodiment, the capacitor can also be a planar capacitor arranged on the chip body. During the wafer processing, an insulating medium, i.e., a capacitive medium, is filled between the upper electrode plate and the lower electrode plate of the planar capacitor.
[0052] Furthermore, one or more holes can be arranged on the upper electrode plate of the planar capacitor, as Figure 6 shown. In this way, the capacitive medium of the planar capacitor can be easily washed away by the reagent, so that the capacitance value of the planar capacitor changes, and it can be determined that the chip has been transferred.
[0053] It should be noted that in the above embodiments, the capacitor electrode plates can be made of a metal material, such as copper or aluminum, etc. The reagent can be, for example, an acidic or alkaline solution used to remove the conductive adhesive.
[0054] Correspondingly, the embodiment of the present invention also provides an RFID chip anti-transfer method. Based on the structural characteristics of the above RFID chips, it is possible to simply and conveniently identify whether the RFID chip has been transferred.
[0055] As Figure 7 shown, it is a flowchart of an RFID chip anti-transfer method provided by the embodiment of the present invention, including the following steps:
[0056] Step 701, during the operation of the RFID chip, measure the capacitance in the RFID chip to obtain a measured value.
[0057] Step 702, obtain the nominal value of the capacitance pre-saved, and the nominal value is measured after the RFID chip is manufactured.
[0058] Among them, the nominal value can be stored in the RFID chip or in the server, and the embodiments of the present invention do not limit this.
[0059] Step 703: Calculate the difference between the measured value and the nominal value.
[0060] Step 704: If the difference is less than the set error threshold, determine that the RFID chip is normal; otherwise, determine that the RFID chip has been transferred.
[0061] The basic principle of capacitance measurement is as Figure 8 shown. Before the measurement starts, reset the upper plate of the capacitor to the voltage Vref1. When the measurement starts, denoted as time t1, charge the capacitor to be measured with a constant current, and start the timer. After charging to Vref2, denoted as time t2, stop the timer. Record the charging time difference t2 - t1 of the capacitor to be measured, and then the capacitance value of the capacitor to be measured can be obtained.
[0062]
[0063] Applying the solution of the present invention to the RFID anti-counterfeiting label can fundamentally solve the situation where the RFID anti-counterfeiting label is reused, and ensure the security of the RFID anti-counterfeiting label in application.
[0064] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.
Claims
1. An RFID chip, characterized in that, The RFID chip includes: a chip body, on which a capacitor is provided, and the capacitor dielectric is an easily corroded insulating material, and the capacitor is used to prevent the chip from being transferred.
2. The RFID chip according to claim 1, characterized in that, The capacitor is provided on the passivation layer of the chip body.
3. The RFID chip according to claim 2, wherein, The capacitor is an interdigital capacitor, and the capacitor dielectric is filled in the gaps of the interdigital capacitor.
4. The RFID chip according to claim 3, wherein The shape of the interdigital capacitor is a regular shape or an irregular shape.
5. The RFID chip according to claim 3, wherein, The layer to which the capacitor dielectric belongs is the top layer or the sub-top layer of the chip.
6. The RFID chip according to claim 1, wherein The capacitor is a parallel plate capacitor, and the capacitor dielectric is filled between the upper plate and the lower plate of the parallel plate capacitor.
7. The RFID chip according to claim 6, wherein, One or more holes are provided on the upper plate.
8. The RFID chip according to claim 3 or 6, characterized in that, The capacitor dielectric is filled during the wafer processing.
9. The RFID chip according to any one of claims 1 to 4, characterized in that, One end of the capacitor is connected to a wire board, and the other end of the capacitor is a pin or an internal node of the chip.
10. A method for preventing the transfer of an RFID chip, characterized in that, The RFID chip includes the RFID chip according to any one of claims 1 to 9; the method includes: During the operation of the RFID chip, measuring the capacitor in the RFID chip to obtain a measured value; Obtaining a nominal value of the capacitor that is pre-saved, and the nominal value is measured after the RFID chip is manufactured; Calculating the difference between the measured value and the nominal value; If the difference is less than a set error threshold, it is determined that the RFID chip is normal; otherwise, it is determined that the RFID chip has been transferred.