JP2006270671A - Method of manufacturing antenna pattern, and method of manufacturing rfid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an antenna pattern with which characteristics of the antenna pattern can be accurately measured even if an aluminum layer is residual around the antenna pattern when forming the antenna pattern by means of etching. <P>SOLUTION: The manufacturing method of forming an antenna pattern 30 in a planar coil shape by etching a metal layer disposed on an insulating film includes: making an outer edge metal layer part 26 surrounding the antenna pattern 30 residual at the outer edge of the antenna pattern 30; and forming a dummy capacitor 60 capable of relaxing interference of the outer edge metal layer part 26 to a resonance circuit including the antenna pattern inside the outer edge metal layer part 26 or the antenna pattern 30 while connecting to the antenna pattern 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an antenna pattern, particularly an RFID antenna pattern.

RFID (Radio Frequency Identification) is equipped with a coiled antenna pattern on a base material such as plastic, and this antenna pattern and capacitive element form a resonant circuit to receive and transmit radio waves of a certain frequency. It's being used.
As disclosed in Patent Document 1, this RFID antenna pattern is manufactured by a method in which a resist pattern is formed on an aluminum layer laminated on a substrate and etched.

When manufacturing an antenna pattern, it is desirable to manufacture a plurality of antenna patterns in the same process in order to improve manufacturing efficiency and reduce product cost. For this reason, a method is employed in which etching is performed so that a plurality of antenna patterns are aligned on a large substrate.
Further, when performing the antenna pattern characteristic inspection, a method is employed in which the inspection is performed sequentially or simultaneously with a plurality of antenna patterns formed on the substrate.
JP 2000-132634 A

By the way, in order to further reduce the product cost, it is desirable to reduce the amount of the aluminum layer to be removed and reduce the amount of etching solution used when forming a plurality of antenna patterns by arranging them by etching. . For this reason, the aluminum layer existing between the antenna patterns is left without being removed during etching, and is removed when each antenna pattern is cut (punched) from the base material. Yes.
However, since the aluminum layer is left around the antenna pattern, the characteristics of the antenna pattern cannot be measured accurately. That is, when the measuring device is brought close to the antenna pattern, there is a problem that a characteristic in which the antenna pattern and the surrounding aluminum layer are integrated is detected.
Although it is possible to estimate the characteristic value of the antenna pattern from the characteristic value obtained by integrating the antenna pattern and the surrounding aluminum layer, there is a problem that it cannot always be estimated accurately.

  The present invention has been made in view of the above-described circumstances. When an antenna pattern is formed by etching, the characteristics of the antenna pattern are accurately measured even when an aluminum layer is left around the antenna pattern. An object of the present invention is to provide a method for manufacturing an antenna pattern.

The antenna pattern manufacturing method according to the present invention employs the following means in order to solve the above problems.
1st invention is a manufacturing method which etches the metal layer arrange | positioned on an insulating film, and forms a planar coil-shaped antenna pattern, The outer edge metal layer part surrounding the said antenna pattern is formed in the outer edge of the said antenna pattern. A dummy capacitor that is allowed to remain and that can mitigate interference of the outer edge metal layer portion with respect to a resonance circuit including the antenna pattern is formed inside the outer edge metal layer portion or the antenna pattern so as to be connected to the antenna pattern. I made it.
According to the present invention, when the planar coil-shaped antenna pattern is formed by etching and the outer edge metal layer portion is left so as to surround the outer edge of the antenna pattern, the resonance frequency of the resonance circuit including the antenna pattern is changed to the outer edge metal layer. By forming a dummy capacitor connected to the antenna pattern at the same time as the antenna pattern, it is possible to easily eliminate the inconvenience that the desired resonance frequency cannot be obtained due to interference by the parts without increasing the manufacturing process. It becomes.
As a result, it is not necessary to remove the outer edge metal layer portion by etching, and the manufacturing cost can be reduced. Moreover, even before the antenna pattern is cut out from the insulating film, the resonance frequency of the resonance circuit including the antenna pattern can be accurately measured.

In addition, in the case where a plurality of the antenna patterns are formed so as to be aligned on the insulating film, the manufacturing cost can be particularly reduced.
Further, when the outer edge metal layer portion is formed so as to imperfectly surround the antenna pattern, the shape of the outer edge metal layer portion is reduced so that interference with the resonance frequency of the resonance circuit including the antenna pattern is reduced. By forming, the capacity of the dummy capacitor can be reduced.
Further, in the case of including an insulating step for insulating the dummy capacitor and the antenna pattern, the unnecessary dummy capacitor is insulated from the antenna pattern when the antenna pattern is used. Thus, a desired resonance frequency can be obtained.
In addition, in the case where the insulating step is performed substantially simultaneously with the step of cutting out the antenna pattern from the insulating film, the manufacturing cost can be suppressed by performing the insulating step and the cutting step in substantially the same step.

The second invention includes a step of forming a planar coil antenna pattern, a step of connecting an IC chip to the antenna pattern, a step of inspecting a resonance frequency of a resonance circuit including the antenna pattern and the IC chip, In the manufacturing of the RFID including the antenna pattern, the manufacturing method of the first invention is used as the antenna pattern forming step.
According to this invention,
Even when an IC chip is connected to the antenna pattern and the resonance frequency of the resonance circuit including the antenna pattern and the IC chip is inspected before the antenna pattern is cut out from the insulating film, it remains so as to surround the outer edge of the antenna pattern. Since the outer edge metal layer portion that has been made is mitigated from interfering with the resonance frequency of the resonance circuit including the antenna pattern and the IC chip, the inspection of the resonance frequency can be performed accurately, and the manufacturing efficiency can be improved. it can. This makes it possible to manufacture a low-cost RFID.

Hereinafter, an embodiment of an antenna pattern manufacturing method of the present invention will be described with reference to the drawings. The number of turns of the antenna pattern shown in each figure is, for example, about 5 to 8, but the number of turns of the coil is simplified in the figures.
FIG. 1 is a schematic diagram showing the configuration of the RFID 10.
The RFID 10 is formed by superposing protective films 14 and 16 such as plastic on an inlet 12 having a planar coil antenna pattern 30 and an IC chip (integrated circuit) 40.
The inlet 12 is obtained by forming a coiled antenna pattern 30 capable of transmitting and receiving electromagnetic waves of a constant frequency on a film such as polyethylene terephthalate (PET). And it arrange | positions so that IC chip 40 may be connected with respect to this antenna pattern 30. FIG.
The IC chip 40 includes a CPU, a ROM, a RAM, a memory, and the like that perform various calculations. Further, a capacitor 42 (see FIG. 4) is provided in the IC chip 40, and constitutes a resonance circuit K together with the antenna pattern 30.

  The protective films 14 and 16 attached to both surfaces of the inlet 12 are colored or colorless and transparent plastics such as polyvinyl carbonate (PVC), heat resistant PVC, amorphous polyester resin (PET-G), polyethylene terephthalate (PET), and the like. Is used. The protective films 14 and 16 may be provided with functions such as antireflection, moisture proofing, and scratch resistance.

Next, a method for manufacturing the RFID 10, particularly a method for manufacturing the antenna pattern 30, will be described with reference to the drawings.
FIG. 2 is a perspective view showing the substrate 20 on which a plurality of antenna patterns 30 are formed. FIG. 3 is a diagram showing the antenna pattern 30. FIG. 4 is a circuit diagram of the resonance circuit K.

First, as shown in FIG. 2, the base material 20 having aluminum (aluminum layer 24) vapor-deposited on both surfaces of an insulating film 22 such as polyethylene terephthalate (PET) is etched to form a plurality of coil-like shapes. An antenna pattern 30 and the like are formed.
Note that a plurality of antenna patterns 30 and the like are formed on the base material 20 in order to improve the production efficiency of the RFID 10.

The antenna pattern 30 is formed on the surface of the substrate 20 as shown in FIG. A terminal portion 30 a to which the IC chip 40 is connected is formed at one end disposed inside the antenna pattern 30. A terminal portion 30b connected to a bridge portion 34 to be described later is formed at the other end disposed outside the antenna pattern 30.
Further, a wiring portion 32 having a terminal portion 32a to which the IC chip 40 is connected and a terminal portion 32b to be connected to the bridge portion 34 is formed in the vicinity of the terminal portion 30a. In addition, the wiring part 32 and the antenna pattern 30 are insulated and formed.

  As shown in FIG. 3B, on the back surface of the base material 20, the terminal portion 34 a disposed at a position facing the terminal portion 30 a and the terminal portion 32 b formed on the front surface through the insulating film 22. And the bridge part 34 which has the terminal part 34b is formed.

Further, as shown in FIGS. 3A and 3B, a dummy capacitor 60 connected to the antenna pattern 30 is formed inside the antenna pattern 30. The dummy capacitor 60 is formed by providing opposing electrodes 60 a and 60 b that are opposed to each other with the insulating film 22 interposed between the front surface and the back surface of the base material 20. The electrodes 60a and 60b are connected to the terminal portion 30a and the terminal portion 34b, respectively.
The capacity of the dummy capacitor 60 is defined by the size of the electrodes 60a and 60b.

  Next, the terminal part 32a and the terminal part 34b, and the terminal part 30b and the terminal part 34a are physically connected by caulking. Thereby, the antenna pattern 30, the bridge part 34, and the wiring part 32 will be in a conductive state.

Next, the IC chip 40 is disposed on the substrate 20. The IC chip 40 is connected to the terminal portion 30a and the terminal portion 32a. As described above, the antenna pattern 30 and the IC chip 40 are connected to form a resonance circuit K including the capacitor 42 and the antenna pattern 30 provided inside the IC chip 40 as shown in FIG. .
The resonance circuit K defines a communication frequency when the RFID 10 performs non-contact communication with an external reader (not shown). Examples of the communication frequency include 13.56 MHz (ISO / IEC18000-3) and 135 KHz (ISO / IEC18000-2).

Next, it is inspected whether or not the resonance circuit K formed of the antenna pattern 30 and the IC chip 40 formed on the base material 20 has substantially the same frequency as the communication frequency described above.
Specifically, a detection head (not shown) capable of measuring a resonance frequency is brought close to the antenna pattern 30 formed on the substrate 20, and the resonance circuit K including the antenna pattern 30 and the IC chip 40 is formed. To detect.
The reason for making the detection heads close is to prevent the adjacent antenna patterns 30 from reacting to the detection head and resonating when there are a plurality of antenna patterns 30. In addition, when there are a plurality of antenna patterns 30, either a method of sequentially bringing the detection heads close to the respective antenna patterns 30 or a method of preparing a plurality of detection heads and bringing them close to the plurality of antenna patterns 30 simultaneously. It may be used.
In this way, the resonance frequency of the resonance circuit K composed of the antenna pattern 30 and the IC chip 40 formed on the substrate 20 is detected.

Incidentally, in order to improve the production efficiency of the RFID 10, a plurality of antenna patterns 30 and the like are usually formed on the base material 20. Furthermore, in order to reduce the manufacturing cost, the aluminum layer 24 other than the antenna pattern 30 is often left without being removed by etching so as to minimize the etching amount of the aluminum layer 24. .
That is, only the aluminum layer 24 in the contour portion such as the antenna pattern 30 is removed by etching. For this reason, the aluminum layer 24 insulated from the antenna pattern 30 and the like remains inside and outside the antenna pattern 30.
The aluminum layer 24 remaining outside the antenna pattern 30 has an annular portion (hereinafter referred to as an outer edge metal layer portion 26) surrounding the antenna pattern 30. Since the outer edge metal layer portion 26 is close to the antenna pattern 30, when the resonance circuit K composed of the antenna pattern 30 and the IC chip 40 resonates, the outer edge metal layer portion 26 resonates integrally with the antenna pattern 30. That is, the outer edge metal layer portion 26 changes (interferes) the resonance frequency of the resonance circuit K including the antenna pattern 30 and the IC chip 40 on the base material 20.
For this reason, even if the detection head is brought close to the resonance circuit K formed of the antenna pattern 30 and the IC chip 40 formed on the base material 20, the accuracy of the resonance circuit K formed of the antenna pattern 30 and the IC chip 40 is correct. It is not possible to detect a resonance frequency.

However, since the dummy capacitor 60 is connected to the antenna pattern 30, it is possible to mitigate (reduce) interference of the outer edge metal layer portion 26 with respect to the resonance circuit K composed of the antenna pattern 30 and the IC chip 40. It has become.
That is, the resonance frequency f of the resonance circuit K composed of the antenna pattern 30 and the IC chip 40 is expressed as follows, assuming that the inductance of the antenna pattern 30 is L and the capacitance of the capacitor 42 in the IC chip 40 is C.
f = 1 / (2π√ (LC)) [Hz]
It is expressed. For this reason, it is possible to obtain a desired resonance frequency by adjusting the C component of the resonance circuit K.
Since the dummy capacitor 60 is arranged in parallel with the capacitor 42 in the IC chip 40, the C component of the above equation can be changed.
That is, by adjusting the capacitance of the dummy capacitor 60, the resonance frequency changed by the interference of the outer metal layer 26 with the resonance circuit K composed of the antenna pattern 30 and the IC chip 40 is changed to the original resonance frequency. It is possible to return. That is, even in the case where the outer edge metal layer portion 26 exists, the antenna pattern 30 can be obtained by bringing the detection head close to the resonance circuit K formed of the antenna pattern 30 and the IC chip 40 formed on the substrate 20. It is possible to detect the resonance frequency of the resonance circuit K including the IC chip 40.

FIG. 5 is a diagram illustrating an experimental result of measuring the resonance frequency of the resonance circuit K. In this case, the design value of the resonance frequency of the resonance circuit K is 14.6 MHz.
As shown in FIG. 5, in the resonance circuit (conventional example) that does not have the dummy capacitor 60, a resonance frequency of about 16 Hz was measured. Thus, the reason why the resonance frequency is larger than the design value is that it is influenced by the outer edge metal layer portion 26 as described above.
On the other hand, in the resonance circuit K, the resonance frequency substantially as designed was measured. Thus, by providing the dummy capacitor 60 in the resonance circuit K, the influence of the outer edge metal layer portion 26 can be suppressed. Therefore, the resonance frequency of the resonance circuit K can be measured substantially accurately.

Next, the antenna pattern 30 is cut out together with the IC chip 40 from the base material 20 to form the inlet 12 of the RFID 10.
In this cutting process, the connection (conduction) between the antenna pattern 30 and the dummy capacitor 60 is disconnected simultaneously with the cutting of the inlet 12.
Specifically, the wiring part between the antenna pattern 30 and the dummy capacitor 60 is punched out from the inlet 12. Alternatively, the dummy capacitor 60 itself is punched from the inlet 12. As a result, a resonance circuit K insulated from the dummy capacitor 60 or without the dummy capacitor 60 is formed in the inlet 12.

Finally, the protective films 14 and 16 are attached to both surfaces of the inlet 12 to complete the RFID 10.
Thus, according to the antenna pattern manufacturing method of the present invention, when the antenna pattern 30 is formed on the substrate 20, even when the outer edge metal layer portion 26 is left on the outer edge of the antenna pattern 30, By providing the dummy capacitor 60 connected to the antenna pattern 30, the interference of the outer edge metal layer portion 26 with respect to the resonance circuit K including the antenna pattern 30 can be reduced.
As a result, the outer edge metal layer portion 26 does not necessarily have to be removed by etching, and the manufacturing cost can be reduced. Even before the antenna pattern 30 is cut out from the base material 20, the resonance frequency of the resonance circuit K including the antenna pattern 30 can be accurately measured.

In the above-described embodiment, the dummy capacitor 60 is formed in the region inside the antenna pattern 30. However, the dummy capacitor 60 may be formed in the outer edge of the antenna pattern 30, that is, in the outer edge metal layer portion 26.
Further, the capacity of the dummy capacitor 60 may be set such that the influence of the outer edge metal layer portion 26 is obtained by experiments in advance in a resonance circuit without the dummy capacitor 60 so that this influence can be counteracted. .

Moreover, although the case where the outer edge metal layer portion 26 is formed so as to completely surround the antenna pattern 30 has been described, it is preferable to reduce the interference of the outer edge metal layer portion 26 with respect to the resonance circuit K including the antenna pattern 30 in advance. . This is because the size (capacitance) of the dummy capacitor 60 can also be reduced.
Specifically, as shown in FIG. 5, the outer edge metal layer portion 26 may be formed so as to surround the antenna pattern 30 incompletely.

It is a schematic diagram which shows the structure of RFID10 of this embodiment. It is a perspective view showing substrate 20 in which a plurality of antenna patterns 30 of this embodiment were formed. It is a figure which shows the antenna pattern 30 of this embodiment. It is a circuit diagram of the resonance circuit K of this embodiment. It is a figure which shows the experimental result which measured the resonant frequency of the resonant circuit K of this embodiment. It is a figure which shows the modification of the outer edge metal layer part.

Explanation of symbols

10 ... RFID, 22 ... insulating film, 24 ... aluminum layer (metal layer), 26 ... outer metal layer, 30 ... antenna pattern, 40 ... IC chip, 60 ... dummy capacitor, K ... resonant circuit

Claims (6)

In the manufacturing method of forming the planar coil-shaped antenna pattern by etching the metal layer disposed on the insulating film,
At the outer edge of the antenna pattern, the outer edge metal layer surrounding the antenna pattern remains, and
A dummy capacitor capable of mitigating interference of the outer edge metal layer portion with respect to a resonance circuit including the antenna pattern is formed inside the outer edge metal layer portion or the antenna pattern, connected to the antenna pattern. Manufacturing method of antenna pattern.   The method for manufacturing an antenna pattern according to claim 1, wherein a plurality of the antenna patterns are formed in an aligned manner on the insulating film.   The method of manufacturing an antenna pattern according to claim 1, wherein the outer edge metal layer portion is formed so as to surround the antenna pattern incompletely.   The method for manufacturing an antenna pattern according to any one of claims 1 to 3, further comprising an insulating step of insulating the dummy capacitor and the antenna pattern.   The method for manufacturing an antenna pattern according to claim 4, wherein the insulating step is performed substantially simultaneously with a step of cutting out the antenna pattern from the insulating film. Forming a planar coil antenna pattern;
Connecting an IC chip to the antenna pattern;
Inspecting a resonance frequency of a resonance circuit including the antenna pattern and the IC chip;
In the manufacture of RFID including
An RFID manufacturing method using the manufacturing method according to claim 1 as the antenna pattern forming step.

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