JP2015064651A - Rfid tag and automatic recognition system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an RFID tag capable of ensuring a communication range and heat resistance and achieving cost reduction as compared with a conventional on-chip antenna-based RFID tag and a conventional packaged RFID tag although being small in size, and an automatic recognition system using the RFID tag.SOLUTION: Provided is an RFID tag including: a resin base material; an IC chip arranged in a central portion on this base material; a single-layer or two-layer antenna arranged on an outer peripheral portion of this IC chip, and connected to the IC chip to form an electrically closed circuit; and an encapsulation material encapsulating the IC chip and the antenna, an operating frequency of the IC chip being 13.56 MHz, and a size of the RFID tag being 10 mm or less in length×10 mm or less in breadth×1.0 mm or less in height, and an automatic recognition system using this RFID tag.

Description

  The present invention relates to an RFID (Radio Frequency Identification) tag that can be used in combination with a general-purpose reader or reader / writer and can send and receive information without contact, and an automatic recognition system using the RFID tag.

  For the purpose of product information, identification, management and anti-counterfeiting, many non-contact RFID tags (hereinafter simply referred to as “RFID tags”) equipped with IC chips are used for products, packaging, cards, documents and the like. Yes. Information such as the product name and price is written on the IC chip. When managing, selling, and using the reader, a reader or a reader / writer (hereinafter, the reader and the reader / writer may be collectively referred to as “reader”). )), The information of these IC chips can be read and used wirelessly. Some information such as the date of manufacture, the factory, and the balance can be written later by a reader / writer. In this way, the RFID tag brings great advantages such as improved convenience of product management, improved safety, and elimination of human error.

  RFID tags are strongly demanded to be small and thin due to the nature of being attached to a product or built in a card. In particular, in recent years, it has been attracting attention as a use for things that have been conventionally managed by engraving and entering lot numbers, or where management itself has not been possible. Specifically, glasses, watches, medical samples, semiconductors, etc. (hereinafter referred to as small, multi-product items that have such a complicated shape, or that are small items with a size of vertical: several centimeters x width: several centimeters or less. )), Which helps to manage the product (sample) factory, workers, date of manufacture, materials used, dimensions, characteristics, inventory quantity, etc., reducing the labor of management workers and preventing mistakes. Can do. In order to realize such a convenient management system, it is indispensable to make the RFID tag smaller and thinner.

  As a relatively small and thin RFID tag, an RFID tag 80 in which an antenna 20 is formed on a film substrate 1 and an IC chip 30 is mounted is disclosed as shown in FIG. ). In addition, as a smaller RFID, after mounting an antenna pattern and an IC chip on a substrate, it is sealed and packaged (Patent Document 3), or in order to make it thinner and flat, without providing a substrate, An IC chip is mounted on an independent antenna pattern and then sealed and packaged (Patent Document 4). Further, as shown in FIG. 2, an RFID tag that is miniaturized to an IC chip size and in which an antenna 20 is directly formed on an IC chip 30 (on-chip antenna) is disclosed (Patent Documents 5 and 6).

JP 2006-221211 A JP 2011-103060 A JP 2010-152449 A JP 2001-052137 A International Publication No. 2005/024949 JP 2007-189499 A

  The RFID tags of the cited documents 1 and 2 are relatively small and thin, and even a general-purpose reader or the like has a communication distance of 200 mm or more. However, as the antenna provided on the film base, the vertical or horizontal size is required to be about several centimeters, so the target to which the RFID tag is attached cannot be handled when the above-described small and multi-product is used. There are significant restrictions on the product and installation.

  The RFID tags of Cited Documents 3 and 4 are as small as several mm square (vertical: several mm × horizontal: several mm; the same applies hereinafter), and can be used for small multi-product types. However, since the RFID tag of the cited document 3 is provided with antennas in multiple layers, the substrate on which the antennas are provided requires a multilayer structure, which is costly and increases the overall thickness. The RFID tag of the cited document 4 uses a lead frame-like member in which a large number of single antennas that are not supported by the base material are connected. Therefore, when the individual RFID tag is cut into individual packages after sealing, the cut surface of the antenna is outside the package. There is concern about the impact on communication characteristics and reliability due to exposure and environmental degradation. Moreover, RFID tags having a size of about several millimeters square as in the cited documents 3 and 4 generally have a communication distance of about several millimeters or less, and cannot be said to be practically sufficient. Although it is possible to increase the communication distance by handling on the side of the reader or the like, there is a problem that usability is poor because a dedicated reader or the like is required and a general-purpose reader or the like cannot be used.

  The RFIDs of the cited documents 5 and 6 have the same size as an IC chip (about several hundred μm square), and can sufficiently cope with small and wide variety products. However, the communication distance is 1 mm or less or as short as the contact level, and there is a problem that work efficiency and flexibility are low in the actual use site. On the other hand, when trying to increase the communication distance, it is necessary to increase the size of the IC chip itself, which increases the cost.

  In the HF band (High Frequency Band) (13.56 MHz band), cards and the like are prevalent, but small RFID tags are not so prevalent. If the RFID tag has a size of about 10 mm square or less and a communication distance of about 20 mm or more, the application range will be greatly expanded, including a small variety of products, a general-purpose reader, NFC ( Since it can be used with Near Field Communication (Smartphone) compatible smartphones, the industrial utility value is very high. In addition, when the applied product is an electronic component such as a semiconductor package or an injection molded product, it is exposed to heat during reflow, molding, or heat generation during use, and thus requires heat resistance of about several seconds at 250 to 300 ° C. There is a problem that such heat resistance is not taken into consideration.

  The present invention has been made in view of the above problems, and can secure a communication distance even if it is small (less than 10 mm square), has heat resistance and environmental resistance, and is a conventional on-chip antenna. It is an object of the present invention to provide an RFID tag capable of reducing cost compared to a packaged one and an automatic recognition system using the RFID tag.

The present invention relates to the following.
1. A resin base material, an IC chip disposed at the center of the base material, and a single layer or two disposed on the outer periphery of the IC chip and connected to the IC chip to form an electrical closed circuit An RFID tag having a layer antenna, the IC chip and a sealing material for sealing the antenna, the IC chip operating frequency is 13.56 MHz, and the RFID tag size is 10 mm or less in length X RFID tag having a width of 10 mm or less and a height of 1.0 mm or less.
2. Item 2. The RFID tag according to item 1, wherein the antenna is a coil antenna.
3. In item 1 or 2, the resonance frequency f _{0 of the} electric circuit formed by including the antenna inductance L and the IC chip capacitance C obtained by the electromagnetic field simulator is at or near the operating frequency of the IC chip. An RFID tag.
4). Item 4. The RFID tag according to any one of Items 1 to 3, wherein the Q value is 11 or more.
5. Item 5. The RFID tag according to any one of Items 1 to 4, wherein the IC chip is directly connected to the end portion of the antenna by wire bonding connection or flip chip connection.
6). Item 6. The RFID tag according to any one of Items 1 to 5, wherein the conductor conductor width / inter-conductor wire distance is 0.05 mm or less / 0.05 mm or less.
7). Item 7. The RFID tag according to any one of Items 1 to 6, wherein the base material has a relative dielectric constant of 3.5 or more.
8). Item 8. The RFID tag according to any one of Items 1 to 7, wherein a polyimide or glass epoxy is used as a base material and a sealing material mainly composed of epoxy, carbon, and silica is used.
9. In any one of Items 1 to 8, an antenna is formed on one or both sides of the base material, and the antenna, the IC chip, and the wire for wire bonding are collectively sealed using a sealing material. The RFID tag in which the antenna, the IC chip, and the wire are not exposed on the surface of the sealing material.
10. Item 10. An automatic recognition system comprising the RFID tag according to any one of items 1 to 9 and a reader or a reader / writer.

  The present invention has been made in view of the above problems, and even with a small size (10 mm square), a communication distance can be secured, heat resistance and environmental resistance, and a conventional on-chip antenna or It is possible to provide an RFID tag and an automatic recognition system using the RFID tag that can reduce costs as compared with a packaged one.

It is the schematic of the conventional RFID tag. It is the schematic of the conventional RFID tag. It is a figure which shows the shape of the antenna of the RFID tag of this embodiment. It is the schematic of the RFID tag of this embodiment. It is a figure which shows the electrical equivalent circuit of the coil antenna which connected IC chip. It is an electrical equivalent circuit of the coil antenna of this embodiment. It is a figure which shows the shape of the antenna of the RFID tag of this embodiment.

  The base material in the present invention supports an antenna and an IC chip. As the substrate, a resin is used. As a resin base material, it has heat resistance and mechanical strength of about several seconds at 250 to 300 ° C., which are necessary when exposed to heat during reflow or molding, or heat generated during use, and has a low coefficient of thermal expansion. Materials are preferred, and as such, glass epoxy, phenol, polyimide, etc. can be used. In order to form an antenna at low cost and without variation, it is effective to form an antenna by etching using a base material with a metal foil in which a metal foil is bonded to one side of the base material. Furthermore, it is effective to use a thin base material of about 10 to 50 μm for making the RFID tag thinner. As a base material, a glass epoxy base material with a copper foil in which a copper foil is bonded to one side or both sides of a glass epoxy base material (for example, product name: MCL-E-67 manufactured by Hitachi Chemical Co., Ltd., glass epoxy thickness 0.2 mm, copper A foil thickness of 9 μm) can be used. The relative permittivity is about 4.6 to 7.0 for paper phenol, about 4.4 to 5.2 for glass epoxy, and about 3.5 for polyimide, and all of these base materials can be used. If the relative dielectric constant is high, the inductance increases, and the antenna can be downsized. Glass epoxy substrates are advantageous in that they are inexpensive, heat resistant, and have high physical strength.

  The antenna of the present invention receives power by electromagnetically coupling with a reader or the like, transmits it to the IC chip, and operates the IC chip. The antenna may be a single layer or two layers, and is preferably formed by etching a glass epoxy substrate with copper foil at low cost and without variation.

  As shown in FIG. 3, the IC chip 30 is arranged at the center of the resin base material 1, and the antenna 20 is arranged on one side or both sides of the base material 1 on the outer periphery of the IC chip 30. Since the antenna 20 is arranged in a region where the length of the outer peripheral portion of the substrate 1 can be taken, the degree of freedom of the antenna shape is expanded and formed including the inductance L of the antenna 20 and the electrostatic capacitance C of the IC chip 30. It is easy to adjust the resonance frequency of the electric circuit (hereinafter also referred to as “LC resonance circuit”). In addition, since the antenna 20 is provided on the outer peripheral portion of the IC chip 30, in the case of a coil antenna, the diameter of the coil increases and the inductance increases, which is advantageous for securing a communication distance and reducing the size. The antenna 20 is connected to the IC chip 30 to form an electrical closed circuit so as not to have an open end. Specific examples of the antenna that is connected to the IC chip 30 to form an electrically closed circuit and does not have an open end include the loop antenna B of FIG. 3 (4) and the coil antenna of FIG. 3 (5). Therefore, even if the RFID tag is small in size, the antenna 20 can be easily designed as an LC circuit, and an inductance can be obtained efficiently in a small area, so it is advantageous to secure a communication distance.

  As shown in FIG. 4, when the antenna 20 is formed on both surfaces of the substrate 1, through-holes are formed so that the front antenna end as shown in FIG. 4 (a) and the back side as shown in FIG. 4 (b) are formed. By connecting the antenna ends, one antenna can be obtained. 4 (a) and 4 (b) are perspective views when viewed from the front side.

  A typical example of the shape of the antenna is shown in FIGS. The shape of the antenna 20 is such that the resonance frequency of the electric circuit (LC resonance circuit) formed including the inductance of the antenna 20 and the capacitance of the IC chip 30 is at or near the operating frequency of the IC chip 30. design. The shape of the antenna 20 includes a meander line antenna (FIG. 3 (2)), a loop antenna (FIGS. 3 (1) and (4)), a coil antenna (FIG. 3 (5)), and a vortex antenna (FIG. 3 (3)). And the like widely used as antennas can be used. Among these, the coil antenna (FIG. 3 (5)) and the loop antenna B (FIG. 3 (4)) that are connected to the IC chip 30 to form an electrical closed circuit are easily designed as LC resonance circuits. In addition, since it is possible to obtain inductance efficiently in a small area, it is desirable in that it can be downsized, and a coil antenna (FIG. 3 (5)) is particularly desirable. A design method of the antenna 20 will be described later. In the case of a coil antenna, it is possible to mount the winding coil with an adhesive or the like, but the coil produced by etching is more stable in performance than the winding coil, and the conductor width / between the conductors Since it is possible to form a fine wiring having a distance of about 0.2 mm / 0.2 mm to 0.05 mm / 0.05 mm, it is advantageous for downsizing and is excellent in mass productivity. Industrially effective.

  FIG. 3 also shows the IC chip 30 and the wire 40 bonded by wire bonding. When the antenna 20 is formed by etching the copper foil of the glass epoxy substrate with copper foil, the copper foil of the portion on which the IC chip 30 is mounted is also left and a die pad (not shown) is formed. When the IC chip 30 is connected by wire bonding or the like, the rigidity is maintained and the yield is improved. A die-bonding film (not shown) is disposed on the copper foil where the IC chip 30 is mounted, and the IC chip 30 is fixed thereon. Although the IC chip 30 may be read-only, it is preferable that information can be written because work history and the like can be written at any time. Thereafter, the IC chip 30 and the antenna 20 are directly connected by wire bonding. In the coil antenna 20 of FIG. 3 (5), two antenna end portions are located with the antenna 20 in between, and the antenna 20 located between them is straddled by wire bonding wires 40, and the antenna end portions are located. By directly connecting the IC chip 30 and the IC chip 30, it is not necessary to provide a jumper wire, so that the cost can be reduced.

  Almost all antennas can be directly connected to each other by flip chip connection by adjusting the wiring location. If multilayer wiring is performed using a double-sided copper foil base material or the like, flip-chip connection is possible in all antennas. By multilayer wiring using a double-sided copper foil base material or the like, especially in a coil antenna, the diameter of the coil can be reduced, so that the vertical and horizontal dimensions of the RFID tag can be reduced, and downsizing can be realized.

  FIG. 5 is a cross-sectional view showing the RFID tag 80 after sealing. The IC chip 30, the antenna 20, and the wire 40 mounted on the die pad 90 on the base material 1 are collectively sealed using the sealing material 10 to protect them. When antennas are formed on both surfaces of the substrate 1, the antenna 20 is protected by forming a solder resist or the like on the entire back surface (the surface on which the IC chip 30 is not mounted). By using a thin substrate 1, the thickness after sealing can be set to, for example, about 0.2 to 1.0 mm. After sealing, all the metal wiring parts such as the IC chip 30, the antenna 20, and the wire 40 are sealed, so that the structure cannot be touched at all from the outside of the sealing material 10. Safety and reliability are also improved from the viewpoint.

As a sealing material, the sealing material normally used with the semiconductor can be used, and a dielectric constant is about 2.6-4.5. If the relative dielectric constant is high, the inductance increases, and the antenna can be downsized.

  The RFID tag manufactured in this manner has a base material with a heat resistance of 180 ° C. or higher, a sealing material with a heat resistance of 150 ° C. or higher, and uses wire bonding. Therefore, an antenna is formed on conventional PET or the like. It has higher heat resistance than RFID tags, and operates normally even at high temperatures. For this reason, when the applied product is an electronic component such as a semiconductor package or an injection molded product, it is exposed to heat during reflow, molding, or heat generation during use, and therefore requires heat resistance of about several seconds at 250 to 300 ° C. However, it can also be used for such applications.

Hereinafter, an antenna design method will be described.
The antenna design uses the resonance frequency determined by the shape of the antenna line, the thickness of the line, the length of the line, etc. as an index. By bringing this resonance frequency close to the operating frequency of the IC chip to be used, the antenna receives the power from the reader / writer and transmits it to the IC chip to operate the IC chip.

It is generally difficult to analytically derive the resonance frequency from the antenna drawing. In practice, a method is often employed in which an antenna is prototyped and experimentally measured. However, since the RFID tag of the present invention is small, it is impossible to accurately prototype the antenna manually. On the other hand, it takes time and cost to fabricate the antenna from etching mask fabrication to etching. End up. For this reason, in the present invention, antenna design is performed using an electromagnetic field simulator (simulator software product name: HFSS manufactured by Ansys Japan Co., Ltd.), thereby reducing time and cost. The resonance frequency is obtained from the simulation result by inputting the shape and material of the antenna, the capacitance of the IC chip, and the like to the electromagnetic field simulator. Then, the resonance frequency f _{0 of the} electric circuit formed by including the antenna inductance L and the IC chip capacitance C obtained by the electromagnetic field simulator is at or near the operating frequency of the IC chip. Design the antenna. Note that the resonance frequency in this case is a frequency at which the imaginary part of the impedance of the electrical closed circuit when the IC chip is connected to both ends of the antenna becomes zero.

It is easy to understand the design principle by considering an electric closed circuit when an IC chip is connected to both ends of a coil antenna, and can be considered as a simple LC resonance circuit. FIG. 6 shows an electrical equivalent circuit of the coil antenna shown in FIG. The resonance frequency f _{0 in} this case is expressed by the following equation (1) using the inductance L of the coil 50 that is an equivalent circuit of the coil antenna and the capacitance C of the capacitor 60 that is an equivalent circuit of the IC chip 30. The

Ｃは使用するＩＣチップ３０の選定によって変えられ、Ｌはコイルアンテナの形状（特にコイルアンテナの直径と巻数）によって調整することができ、その結果、目的の共振周波数ｆ_０を実現することができる。特にＬの調整は有効で、コイルアンテナの直径を大きくしたり、巻数を増やすことでＬが増加し、その結果ｆ_０は減少する。

C is changed by the selection of the IC chip 30 to be used, L is can be adjusted by the shape of the coil antenna (particularly the coil antenna diameter and number of turns), as a result, it is possible to realize a resonance frequency f ₀ of the object . Adjustment of L is particularly effective, and L is increased by increasing the diameter of the coil antenna or increasing the number of turns. As a result, f ₀ is decreased.

  The resonance frequency (operating frequency) of the RFID tag (IC chip) is preferably in the range of 13.56 MHz to 2.45 GHz, which is particularly commercially useful in radio law. In the case of RFID near the operating frequency of 0.86 to 0.96 GHz in the UHF band (Ultra High Frequency Band), the wavelength of the radio wave is about 30 cm. On the other hand, the size of the IC chip for the UHF band is usually 0. Since it is 6 mm square or less, it is difficult to form an antenna on which the IC chip operates normally on the IC chip in the on-chip antenna system. Further, even with an RFID tag having a size of about several mm square, an antenna using a conventional design method can only obtain a communication distance of about several mm. However, according to the RFID tag of the present invention based on the design method using the electromagnetic field simulator described above, the communication distance for the operation of the RFID tag can be achieved even with a several mm square antenna without using a conventional several cm square antenna. There is an excellent feature that can be greatly expanded.

  As shown in the following formula (2), the communication distance can be increased by designing the antenna Q value to be particularly high.

ここで、（２）式中の各記号は、以下を示す。
ω_０ ： 共振周波数
ω_２−ω_１ ： 共振周波数の半値幅
Ｌ ： アンテナのインダクタンス
Ｒ ： アンテナの直列抵抗
本発明では、Ｒを低くし、Ｌを高くするために、図７（ａ）よりは図７（ｂ）のように、ＲＦＩＤタグの外周に近い位置にアンテナが集中するように設計した。

Here, each symbol in the formula (2) indicates the following.
ω ₀ : Resonance frequency ω ₂ −ω ₁ : Half width of resonance frequency L: Antenna inductance R: Antenna series resistance In the present invention, in order to reduce R and increase L, in FIG. As shown in FIG. 7B, the antenna is designed to concentrate at a position close to the outer periphery of the RFID tag.

  The RFID tag of the present invention can be used by being embedded in a semiconductor device or the like. Further, it can be used for management etc. by being attached to a product or sample like a label with a double-sided tape or the like, and can be easily removed when the product is sold. Furthermore, by combining the RFID tag of the present invention with a reader, etc., automatic recognition with a long communication distance and good workability is possible even for small and multi-product items such as glasses, watches, medical samples, semiconductors, etc. The system can be configured. In this case, since the RFID tag of the present invention has a long communication distance, an automatic recognition system can be configured in combination with a general-purpose reader or the like.

Example 1
As a resin substrate, a glass epoxy substrate with a single-sided copper foil (MCL-E-67, manufactured by Hitachi Chemical Co., Ltd., glass epoxy thickness 0.2 mm, copper foil thickness 9 μm, bonded to one side of a glass epoxy substrate) ) Was prepared. By etching the copper foil of the glass epoxy substrate with copper foil, the coil antenna as shown in FIG. 3 (5) is within the range of 10 mm square, and the conductor wire width / interconductor wire width is 0.05 mm / 0.00 mm. It was formed at 05 mm. At the same time, a die pad (not shown) for mounting an IC chip was formed.

  Next, an IC chip having a size of about 0.7 mm × 0.7 mm × 0.1 mm, a capacitance of 50 pF, and an operating frequency of 13.56 MHz was used. This IC chip was mounted on a die pad using a die bonding material, and the antenna and the IC chip were directly connected by wire bonding. Next, the antenna, IC chip, and wire for wire bonding on one side of the substrate were sealed with a sealing material. Finally, the RFID tag was manufactured by dicing to a required size.

(Example 2)
By etching the copper foil of the glass epoxy substrate with a single-sided copper foil, a coil antenna as shown in FIG. 3 (5) was formed within a range of 9.5 mm square. Otherwise, an RFID tag was produced in the same manner as in Example 1.

(Example 3)
By etching the copper foil of the glass epoxy substrate with single-sided copper foil, a coil antenna as shown in FIG. 3 (5) was formed within a 7 mm square. Otherwise, an RFID tag was produced in the same manner as in Example 1.

Example 4
As a resin base material, a glass epoxy base material with a double-sided copper foil in which a copper foil was bonded to both sides of a glass epoxy base material was prepared. By etching the copper foil of the glass epoxy substrate with double-sided copper foil, the coil antenna as shown in FIG. 3 (5) is within a range of 10 mm square, and the conductor wire width / interconductor wire width is 0.05 mm / 0. It was formed on both sides with a thickness of 0.05 mm and connected with through holes to form a single coil antenna. Otherwise, an RFID tag was produced in the same manner as in Example 1.

(Example 5)
By etching the copper foil of the glass epoxy substrate with double-sided copper foil, a coil antenna as shown in FIG. 3 (5) was formed in a 7.4 mm square range. Otherwise, an RFID tag was produced in the same manner as in Example 1.

  The reading evaluation method and experimental results will be described below. As a reader / writer, product name: FM07-B / PK05 (output: 10 mW) manufactured by GL Sciences Inc. was used. The reading evaluation of the RFID tag 80 was performed in a state where there is no obstacle in a 25 cm square around the reading part of the reader / writer. The maximum distance from the reader / writer reading unit to the RFID tag 80 when the RFID could be read by the reader / writer was measured.

  The simulation results and reading evaluation results of Examples 1 to 3 are shown in Table 1. From Table 1, in the coil antenna connected to the IC chip to form an electrical closed circuit, the resonance frequency by the electromagnetic simulator is 13.1 to 13.6 MHz, and the operating frequency of the IC chip is generally 13. It is close to about 56MHz. With a size of 10 mm square or less, a reading distance more than twice the size of one side can be realized. The Q value was 11 or more in all samples.

  The simulation results and reading evaluation results of Examples 4 and 5 are shown in Table 2. With a size of 10 mm or less, a reading distance of 1 to 2 times or more of one side of the size can be realized. When the Q value was 11 or more, the reading distance was twice or more.

  As an evaluation of heat resistance, 20 RFID tags of Example 2 were immersed in a solder bath of 260 ° C. and 288 ° C., and the reading distance was measured before and after that. The average value of the results is shown in Table 3. There was no sample that could not be read after immersion for 10 minutes, and the reading distance was 20% or less of the change rate compared to the initial value.

  For evaluation of heat resistance, 20 RFID tags of Example 2 were stored in a high-temperature bath at 125 ° C., and the reading distance was measured before and after that. The average value of the results is shown in Table 4. There was no sample that could not be read after 1000 hours, and the reading distance was 20% or less of the change rate compared to the initial value.

  The RFID tag of the present invention is a product, packaging, card, document, glasses, watch (especially a small watch or the like), semiconductor, medical use (sample collected from a patient, etc.), identification, information presentation, It can be used for information recording and anti-counterfeiting purposes.

DESCRIPTION OF SYMBOLS 1 Base material 10 Sealing material 20 Antenna 30 IC chip 40 Wire 50 of wire bonding Coil (antenna)
60 Capacitor (IC chip)
70 Port 80 input during simulation RFID tag 90 Die pad 100 Through hole

Claims (10)

A resin base material, an IC chip disposed at the center of the base material, and a single layer or two disposed on the outer periphery of the IC chip and connected to the IC chip to form an electrical closed circuit An RFID tag having a layer antenna and a sealing material for sealing the IC chip and the antenna,
The operating frequency of the IC chip is 13.56 MHz,
An RFID tag in which the size of the RFID tag is 10 mm or less × 10 mm or less × 1.0 mm or less in height.   The RFID tag according to claim 1, wherein the antenna is a coil antenna. According to claim 1 or 2, obtained by the electromagnetic field simulator, the resonant frequency f ₀ of the electrical circuit formed including the capacitance C of the inductance L and the IC chip of the antenna, IC chip operating frequency or near the RFID tag.   4. The RFID tag according to claim 1, wherein the Q value is 11 or more.   The RFID tag according to any one of claims 1 to 4, wherein the IC chip is directly connected to the end portion of the antenna by wire bonding connection or flip chip connection.   6. The RFID tag according to claim 1, wherein the conductor wire width / inter-conductor wire distance of the antenna is 0.05 mm or less / 0.05 mm or less.   7. The RFID tag according to claim 1, wherein the base material has a relative dielectric constant of 3.5 or more.   The RFID tag according to any one of claims 1 to 7, wherein a polyimide or glass epoxy is used as a base material and a sealing material mainly composed of epoxy, carbon, and silica is used.   9. The antenna according to claim 1, wherein an antenna is formed on one side or both sides of the base material, and the antenna, the IC chip, and the wire for wire bonding are collectively sealed using a sealing material. In the RFID tag, the antenna, the IC chip, and the wire are not exposed on the surface of the sealing material.   An automatic recognition system comprising the RFID tag according to claim 1 and a reader or a reader / writer.

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