JP2009009591A - Manufacturing method of radio ic tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a low cost thin radio IC tag having an antenna circuit excellent in communication characteristics. <P>SOLUTION: The manufacturing method of the radio IC tag is characterized in that after forming the same pattern as that of the antenna circuit using solderable resin containing silver coat nickel powder or silver coat copper powder and having wettability to melted solder on the surface of a base material made of paper, the antenna circuit is formed on the pattern having excellent contact property with the base material using the melted solder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wireless IC tag. More specifically, the present invention relates to a method of manufacturing a wireless IC tag having an antenna circuit with excellent communication characteristics, which is low in cost and thin.

  A wireless IC tag (including a wireless IC card; hereinafter, in principle, referred to as an “IC tag”) generally has an antenna circuit formed on the surface of an insulating substrate such as a resin film. An IC chip is mounted on the substrate on which the IC chip is formed, and the IC chip and the antenna circuit are connected.

  Since the IC tag includes an IC chip, the amount of information that can be recorded is much larger than that of a bar code or an identification tag, and new information can be freely written. In particular, planar IC tags are widely used because they are convenient to carry and attach to articles.

  In order to further use the IC tag, there is a strong demand for an IC tag that has excellent communication characteristics and is cheaper.

Regarding these, for example, Patent Document 1 discloses an IC tag having a circuit pattern made of a metal such as copper or silver or a conductive paste.
As a method for forming a circuit pattern, a method of winding a coated conductor in a coil shape and a method of forming a coil pattern by etching a conductive metal such as copper laminated on a base material are disclosed.

JP 2006-304184 A

  However, in the description of Patent Document 1, metals such as copper and silver are expensive, and it is difficult to reduce the material cost. On the other hand, a circuit pattern made of a conductive paste is inferior in conductivity to a coil pattern made of metal thin film formed by vapor deposition or plating, increases the power consumed by the coil pattern, and has a short communication distance, that is, communication. Characteristics are degraded. In order to eliminate this drawback, it is necessary to increase the line width of the coil pattern. However, there arises a problem that a stray capacitance is newly generated as well as an increase in material cost accompanying the expansion of the line width.

Moreover, the method of winding the coated conductor in a coil shape is complicated, and it is difficult to reduce the manufacturing cost.
And the method of forming a coil pattern by forming a copper thin film on the entire surface of an insulating resin and performing etching is accompanied by not only those operations but also pretreatment and waste treatment. The work is complicated, the manufacturing facilities are complicated and large, and the base materials that can be used are also limited.
In addition to copper, there is a method of using aluminum or silver, but these materials including copper have a drawback that they have a high melting point and are difficult to process.
In addition, copper is susceptible to oxidation and is not suitable for heat treatment, aluminum is disadvantageous in that it has low electrical conductivity, and silver is poor in spreadability and difficult to be made into a foil.

  In view of these problems, it is an object of the present invention to provide an IC tag manufacturing method that has excellent communication characteristics and is less expensive.

  The present invention has been made for the purpose of solving the above problems. The first to eighth techniques related to the present invention will be described below. The present invention claims a technique that combines the sixth technique and the seventh technique.

The first technique related to the present invention is:
A wireless IC tag having an electrically insulating substrate, an antenna circuit provided on the surface of the substrate, and an IC chip connected to the antenna circuit, wherein the antenna circuit is formed of solder The wireless IC tag is characterized in that the IC chip is connected to the antenna circuit via a solder paste containing solder and an adhesive thermosetting resin.

In the first technique, since the antenna circuit of the IC tag is formed of solder that is cheaper than aluminum, copper, and silver, an inexpensive IC tag can be provided.
In addition, since solder is more conductive than a conventional conductive paste, an IC tag excellent in communication characteristics can be provided without extremely increasing the line width of the antenna circuit.
Furthermore, since solder has a low melting point and excellent processability, it has a high degree of freedom in the manufacturing process, there is no need to use complicated manufacturing facilities or large-scale manufacturing facilities, and there is a large degree of freedom in the selection of base materials, resulting in manufacturing costs. The IC tag can be easily provided without causing an increase in the number of the tags.

  The solder used for forming the antenna circuit is not particularly limited. For example, in addition to normal lead and tin alloy solder (melting point is about 183 ° C.), lead-free solder such as Sn—Ag—Cu system, Other solders such as silver solder can be applied.

  In the first technique, since the IC chip and the antenna circuit are connected via a solder paste containing solder and an adhesive thermosetting resin, an extremely expensive anisotropic conductive paste as in the prior art is used. There is no need to connect the IC chip and the antenna circuit by a method using (ACP) (Japanese Patent Laid-Open No. 2006-304184) or a method using ultrasonic melting. Therefore, a cheaper IC tag can be provided.

  The antenna circuit and the IC chip (electrodes) are connected via a solder paste containing solder and an adhesive thermosetting resin. The solder of the solder component of the solder paste is not particularly limited, but in order not to cause damage to the antenna circuit, the melting point of the solder used for forming the antenna circuit, such as Bi-Sn solder having a particularly low melting point among various solders. It is preferable to use a solder having a melting point not exceeding.

  In the first technique, the material of the base material is not limited as long as treatment for forming the antenna circuit and electrical connection of the antenna circuit is possible. Since the antenna circuit is formed of solder having a low melting point, it is possible to use a base material made of paper, synthetic resin, glass, or the like that has insufficient heat resistance. Among these, when glass is used for the substrate, the antenna circuit can be directly formed on the substrate surface by a method such as special flux or ultrasonic soldering.

  In the first technique, the antenna circuit may be transferred to the base material instead of directly forming the antenna circuit on the base material.

A second technique related to the present invention is the above-described wireless IC tag,
The wireless IC tag is characterized in that the substrate is made of paper.

In the second technique, since inexpensive paper is used as the base material, the material cost can be further reduced.
Further, since it is easy to obtain a thin material for paper, it is possible to easily form a thinner IC tag.

Also, unlike the base material made of synthetic resin, the paper base material is a pattern material, even when the surface roughening treatment is not applied when printing the paste pattern material in the circuit pattern formation. Since it does not flow out to the surroundings, it is easy to form an accurate pattern and the workability is excellent. Moreover, since the applied paste-like pattern material is dyed into the paper, the adhesiveness is also good.
Furthermore, paper generally has better heat resistance than resin. For this reason, if the base material is made of paper, the work for forming the antenna circuit using molten solder becomes easier.

In addition, "made of paper" here is not particularly limited, and is not only pure paper (cellulose, resin pulp) but also impregnated with resin, or some surface is processed. Also good.
Of the paper base materials, glassine paper (paraffin paper) is preferably used because a solder antenna circuit can be formed accurately and easily.
The glassine paper here includes smooth heat-resistant paper obtained by applying silicon processing to the surface of the glassine paper.

A third technique related to the present invention is the above-described wireless IC tag,
The wireless IC tag is characterized in that the IC chip is provided on the antenna circuit surface side of the substrate.

  In the third technique, since the IC chip is provided on the antenna circuit surface side of the substrate, the IC tag can be made thinner.

A fourth technology related to the present invention is the above-mentioned wireless IC tag,
The wireless IC tag is characterized in that a sheet made of a high dielectric constant material is attached to the base material.

  In the fourth technology, an IC tag having excellent communication characteristics even when mounted on a metal body while ensuring the thinness of the IC tag with a simple structure of attaching a sheet made of a high dielectric constant material. Can do.

A fifth technique related to the present invention is the above-described wireless IC tag,
The wireless IC tag is characterized in that the substrate is a substrate made of a high dielectric constant material.

  In the fifth technology, instead of sticking a sheet made of a high dielectric constant material to the base material, the base material itself is made of a high dielectric constant material, so that a thinner IC tag having excellent communication characteristics It can be.

The sixth technique related to the present invention is:
After forming the same pattern as the antenna circuit on the surface of the electrically insulating base material using a solderable resin having wettability to the molten solder, The wireless IC tag manufacturing method is characterized in that the antenna circuit is formed on the pattern having excellent adhesion.

  In the sixth technique, the same pattern as the antenna circuit is formed on the surface of the base material in advance using a material that has wettability with respect to the melted solder. The antenna circuit can be easily formed.

  The material having wettability with the molten solder is not particularly limited, and for example, various metal particles can be used. Among these, nickel particles or copper particles whose surfaces are coated with silver are preferable because of good wettability of molten solder.

  When such metal particles are used, the method for forming the same pattern as the antenna circuit with the metal particles is not particularly limited. For example, a method such as vapor deposition can be applied. Preferably, after forming a coating film made of an adhesive resin by screen printing, the metal particles are sprayed, and extra metal particles are removed by removing the metal particles not attached to the adhesive resin. A method for removing metal particles can be applied. According to this method, the amount of metal particles used can be reduced as much as possible, and a thin pattern can be easily formed.

  The method of forming the antenna circuit made of solder on the pattern made of the metal particles is, for example, when using a normal paper base material that is not water resistant, printing cream solder on the entire surface of the base material. A cream solder reflow method is preferable, in which it is applied and then melted by heating to wet and spread the surface of the conductive base, and the molten solder in a ball shape at other locations is blown off with nitrogen. In addition, if it is paper with water resistance, it is also possible to employ | adopt the flow dip immersed in a molten solder tank.

Furthermore, the solderable resin can easily form a pattern on the substrate by printing such as screen printing. For this reason, in the sixth technique, it is possible to easily form a solder antenna circuit having a predetermined pattern.
In addition, since the solderable resin has excellent adhesion to the base material, the antenna circuit can be more firmly fixed to the base material.

  The solderable resin applied to the sixth technique is not particularly limited, and examples thereof include those containing a metal powder, a resin binder, and an unsaturated fatty acid in an organic solvent. Examples of the metal powder include silver powder, copper powder, nickel powder, aluminum powder, silver-coated copper powder, silver-coated nickel powder, and silver-copper alloy powder. Copper powder or a mixed powder of these powder and silver powder is preferred.

The resin binder may be a thermosetting resin such as an epoxy resin, a melamine resin, a phenol resin, or a polyimide resin, but an epoxy resin or a phenol resin is preferable from the viewpoint of coating properties. Of these, the thermosetting resin is preferably a low-temperature (200 ° C. or lower) curable resin since the influence of heating on the substrate can be suppressed as much as possible.
Furthermore, unsaturated fatty acids such as oleic acid, linoleic acid, and linolenic acid may be dissolved in the solderable resin. Of these, oleic acid is preferred from the viewpoint of preventing oxidation of the metal powder surface and promoting the destruction of the resulting oxide film.

  The organic solvent used for making the solderable resin into a paste suitable for printing is not particularly limited as long as the thermosetting resin is uniformly dispersed in the paste. For example, butyl carbitol, Examples thereof include organic solvents such as methyl carbitol and Solvesso 150.

  Note that the mixing ratio of the metal powder and the resin in the solderable resin is not particularly limited as long as it is appropriately determined so that the solder can be joined. A commercially available product may be used as the conductive resin containing the metal powder and capable of being soldered.

A seventh technique related to the present invention is a method of manufacturing the above-mentioned wireless IC tag,
A method of manufacturing a wireless IC tag, wherein the base material is made of paper.

In the seventh technique, since inexpensive paper is used as the base material, the material cost can be further reduced.
Further, since it is easy to obtain a thin material for paper, it is possible to easily form a thinner IC tag.

Also, unlike the base material made of synthetic resin, the paper base material is a pattern material, even when the surface roughening treatment is not applied when printing the paste pattern material in the circuit pattern formation. Since it does not flow out to the surroundings, it is easy to form an accurate pattern and the workability is excellent. Moreover, since the applied paste-like pattern material is dyed into the paper, the adhesiveness is also good.
Furthermore, paper generally has better heat resistance than resin. For this reason, if the base material is made of paper, the work for forming the antenna circuit using molten solder becomes easier.

The present invention claims a technique that combines the sixth technique and the seventh technique. That is, the present invention
The same pattern as the antenna circuit was formed on the surface of the paper substrate using a solderable resin containing silver-coated nickel powder or silver-coated copper powder and having wettability to the molten solder. Thereafter, the antenna circuit is formed on the pattern having excellent adhesion to a base material using molten solder.

  The present invention has the effects described in the sixth technique and the seventh technique. In particular, silver-coated nickel powder and silver-coated copper powder are excellent in solderability as described above.

The eighth technique related to the present invention is:
Providing an antenna circuit formed of a material having wettability to molten solder on an electrically insulating substrate;
A step of providing an IC chip on the antenna circuit via a solder paste containing solder and an adhesive thermosetting resin;
Heating and melting the solder paste at a temperature equal to or higher than the melting point of the solder component;
A method of manufacturing a wireless IC tag comprising the step of connecting the IC chip to the antenna circuit by thermosetting the adhesive thermosetting resin of the solder paste at a temperature below the melting point of the solder component It is.

  In the eighth technique, when an IC chip is provided on an antenna circuit formed of a material having wettability with respect to molten solder, a solder paste containing solder and an adhesive thermosetting resin is applied, and then the solder paste Is heated and melted at a temperature equal to or higher than the melting point of the solder component and then the adhesive thermosetting resin of the solder paste is thermally cured at a temperature equal to or lower than the melting point of the solder component. It can be firmly bonded to the substrate.

  In the solder paste heated and melted at a temperature equal to or higher than the melting point of the solder component, the inventor found that while the adhesive thermosetting resin component contained in the solder paste was uncured, the molten solder component was the electrode portion of the IC chip. In this case, a portion rich in solder components and a portion rich in adhesive thermosetting resin are produced, and this phenomenon occurs even when the IC chip is not accurately mounted to the position of the joint portion of the antenna circuit. Has found that it can move itself to an appropriate position, leading to the eighth technique. In other words, the IC chip is bonded to the antenna circuit in the portion where the solder component is rich, and the IC chip is firmly fixed to the base material in the portion where the adhesive thermosetting resin is rich. Play a role of self-movement.

  In the eighth technique, the adhesive thermosetting resin is not particularly limited, and for example, thermosetting resins such as the epoxy resin, melamine resin, phenol resin, and polyimide resin can be applied. Note that it is preferable to use a low-temperature curable resin because it can be easily cured without damaging the antenna circuit and the base material.

  Further, the solder of the solder component is not particularly limited, but in order not to cause damage to the antenna circuit, for example, In-Sn solder (melting point 118 ° C.) or Bi—Sn solder (melting point 132 ° C.). Such a low melting point solder is preferable, and Bi-Sn solder is particularly preferable because it is inexpensive.

  As described above, as a means for fixing the IC chip to the antenna circuit, conventionally, a method using an extremely expensive anisotropic conductive paste (ACP) or a method using ultrasonic melting is used. In addition, since the electrode interval is very fine, very high-precision positioning is required when mounting the IC chip. On the other hand, in the eighth technique, since the IC chip can be fixed using inexpensive materials and means, the IC tag can be provided at a lower cost.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in communication characteristics, the manufacturing method of a cheaper IC tag can be provided.

  Hereinafter, the present invention will be described based on the best mode. Note that the present invention is not limited to the following embodiments. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

(First embodiment)
(Configuration of IC tag)
The present embodiment will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of an IC tag according to the present embodiment.
In FIG. 1, 1 is an IC tag, and 2 is a base material (glassine paper manufactured by Lintec). The antenna circuit is composed of 3 to 6, and 4 and 6 are both end portions of the antenna circuit. Reference numeral 7 denotes an IC chip (I-CODE SLI manufactured by PHILIPS). Two electrodes (not shown) of the IC chip 7 are connected by antenna circuits 3 and 5, respectively. Terminals 4 and 6 of the antenna circuit are connected by jumper wires 8 (polyurethane wires having a diameter of 0.05 mm, film thickness of 5 μm or more, manufactured by Riken Electric Wire Co., Ltd.)
Finally, the IC tag shown in FIG. 1 is laminated with a PET film (commercial product: not shown) using a commercially available laminating apparatus (110 ° C. setting), so that the IC tag as a product is obtained. Complete.
This will be described in more detail below with reference to FIGS.

(Formation of antenna circuit)
FIG. 2 is a diagram showing a pattern of an antenna circuit in the IC tag shown in FIG.
The antenna circuits 3 and 5 are formed of Sn-Ag-Cu solder (Sn-3.5Ag-0.5Cu). The antenna circuits 3 and 5 are formed by the following procedure.
Glassine paper (Glasin F133 kg) is fixed using static electricity to form a substrate. Furthermore, the pattern shown in FIG. 2 was screen printed (printing conditions: ST325 mesh + emulsion thickness 10 μm) using a solderable resin (A-5050, manufactured by Nippon Paint Co., Ltd.), and then at 160 ° C. for 30 minutes. The resin was cured by heating. The pattern was adjusted so that the line width was 0.75 mm and the line interval was 0.25 mm.

On the obtained pattern, φ0.6 mm flux-containing yarn solder (Sn—Ag—Cu series) was coated using a soldering iron (set temperature: 325 ° C.). After removing the solder on the place other than the pattern, both ends of the jumper wire were soldered to the ends 4 and 6 of the antenna circuits 3 and 5, respectively.
Thereafter, the flux was washed and dried to form antenna circuits 3 and 5.

(IC chip mounting)
Next, an IC chip 7 was mounted. FIG. 3 is a diagram conceptually illustrating a state in which the IC chip 7 is mounted on the base material 2, and proceeds from (a) to (c) in order. As shown in FIG. 3A, a solder paste containing solder and an adhesive thermosetting resin using a dispenser (TYCAP-5401-11, manufactured by Tamura Chemical Co., Ltd., Sn-) between the antenna circuits 3 and 5 is used. A predetermined amount of Bi-based solder paste) 11 is applied. Thereafter, as shown in FIG. 3B, the two electrodes 12 and 13 of the IC chip 7 are temporarily placed on the substrate so as to contact the antenna circuits 3 and 5, respectively.

  Heat at 160 ° C. for 10 seconds to melt the solder component contained in the solder paste. Thereafter, the temperature is lowered to 130 ° C. and held for 30 minutes to thermally cure the adhesive thermosetting resin.

  At this time, while the adhesive thermosetting resin component is uncured, the molten solder component is in the vicinity of the surfaces of the antenna circuits 3 and 5 including the electrodes 12 and 13 and the solder layer having good wettability to the solder component. As a result, a solder-rich portion 14 is generated. On the other hand, an adhesive thermosetting resin component rich portion 15 is generated between the electrode 12 and the electrode 13.

  At this time, since the IC chip was temporarily placed by hand, the solder-rich portion 14 and the adhesive thermosetting were not attached to the predetermined position even though the IC chip was not mounted at an accurate position. It was confirmed that the balance of the force generated by the generation of the part 15 rich in the functional resin component self-moves the IC chip to an appropriate position.

  In this state, the solder paste 11 is solidified, and the electrodes 12 and 13 and the antenna circuits 3 and 5 are joined by the solder-rich portion 14. At this time, the antenna circuit 3 and the antenna circuit 5 were not short-circuited, and the main body of the IC chip 7 was firmly bonded to the substrate 2 by the portion 15 rich in the adhesive thermosetting resin component.

(IC tag operation check)
Next, the operation of the produced IC tag was confirmed. Specifically, in addition to the impedance measurement, a communication distance measurement using a reader / writer (Welcat, EFG-310-01), a Dip meter (Mita Radio Laboratory, DMC-230S2) was used. The resonance frequency before and after the surface lamination was measured.

(Operation check result)
The operation confirmation result of the IC tag in the first embodiment was as follows.
(I) Impedance: 13-15Ω
(B) Resonance frequency (before lamination): 14.20 to 14.30 MHz
Resonance frequency (after lamination): 13.90 to 14.10 MHz
(C) Communication distance (after lamination, in the air): 60 to 65 mm

(Second Embodiment)
(Configuration of IC tag)
IC is used in the same manner as in the first embodiment except that glassine paper (glassine W87.5 kg) is used as the base material and one of the two-chip patterns shown in FIG. 4 is used as the antenna circuit pattern. A tag was fabricated and operation was confirmed.

(Operation check result)
The operation confirmation result of the IC tag in the second embodiment is as follows.
(I) Impedance: 12-17Ω
(B) Resonance frequency (before lamination): 13.80 to 13.90 MHz
Resonance frequency (after lamination): 13.40 to 13.60 MHz
(C) Communication distance (after lamination, in the air): 40 to 45 mm

(Third embodiment)
Except that the antenna circuit pattern was changed to the pattern shown in FIG. 5, an IC tag was manufactured and the operation was confirmed in the same manner as in the first embodiment.

(Operation check result)
The operation confirmation result of the IC tag in the third embodiment was as follows.
(I) Impedance: 14-16Ω
(B) Resonance frequency (before lamination): 14.50-14.60 MHz
Resonance frequency (after lamination): 14.10 to 14.30 MHz
(C) Communication distance (after lamination, in the air): 35 to 40 mm

  From the above operation confirmation results, the IC tags according to the first to third embodiments have good antenna circuit formation and good connection between the IC chip and the antenna circuit, and a sufficiently small impedance is achieved. As a result, good characteristics were obtained in the communication distance. It was also confirmed that the IC chip was firmly fixed to the substrate.

(Production of IC tag with a sheet of high dielectric constant material)
However, when the IC tag according to the first to third embodiments was mounted on a metal body, it was found that communication was extremely difficult. Therefore, when a sheet made of a high dielectric constant material (a ferrite sheet having a thickness of 150 μm and an initial dielectric constant of 30) was pasted on the back surface of the IC tag (the surface opposite to the antenna circuit forming surface), the operation was confirmed. An IC tag operable even when mounted on a metal body could be obtained.

1 is a conceptual diagram of an IC tag according to a first embodiment of the present invention. It is a figure which shows the pattern of the antenna circuit concerning the 1st Embodiment of this invention. It is a figure which shows notionally the mode of mounting of the IC chip in this invention. It is a figure which shows the pattern of the antenna circuit concerning the 2nd Embodiment of this invention. It is a figure which shows the pattern of the antenna circuit concerning the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 IC tag 2 Base material 3, 5 Antenna circuit 4, 6 End of antenna circuit 7 IC chip 8 Jumper wire 11 Solder paste 12, 13 Electrode 14 Solder rich portion 15 Adhesive thermosetting resin component rich portion

Claims (1)

  The same pattern as the antenna circuit was formed on the surface of the paper substrate using a solderable resin containing silver-coated nickel powder or silver-coated copper powder and having wettability to the molten solder. Thereafter, the antenna circuit is formed on the pattern having excellent adhesion to the base material by using molten solder, and a method of manufacturing a wireless IC tag, wherein the antenna circuit is formed.

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