JP3409995B2 - Inductance element and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type inductance element used for mobile communication equipment used in a high frequency band such as a mobile phone.

[0002]

2. Description of the Related Art Conventionally, an inductance element has been manufactured by winding an insulating coated wire around a core made of ferrite or the like to form a coil, and forming electrodes on both ends of the coil. However, in such a method, the manufacturing process is complicated, the apparatus becomes large, and the manufacturing cost becomes high. In addition, the workability of the winding process is poor, and it is difficult to reduce the size of the device.

To solve this problem, various inductance elements that do not use windings have been proposed. JP-A-54-140
No. 164 and Japanese Patent Publication No. 62-8924, a conductor film is formed on the surface of a magnetic core made of ferrite, synthetic resin, insulating ceramic or the like by a method such as electroless plating or vapor deposition, and is cut into a spiral shape. A method of obtaining an inductance element by doing is described. Further, Japanese Patent Application Laid-Open No. 6-215950 describes a method of obtaining a coil by forming a conductive layer in a groove of a base having spiral grooves and forming a coil pattern. With such a configuration, the coil conductor and the end electrode can be formed at the same time, and the manufacturing process can be significantly reduced.

By the way, in recent years, with the progress of mobile communication devices used in high frequency bands such as mobile phones, there has been a further demand for miniaturization, weight reduction and higher band of inductance elements used therein. In order to meet this demand, the substrate of the inductance element is required to have a low dielectric property in order to improve excellent high frequency transmission characteristics, and materials are being developed. When a magnetic core with low dielectric properties is used, the distributed capacitance of static electricity is reduced and the self-resonance frequency is increased to extend the frequency characteristics of the Q value,
The loss at high frequencies can be reduced. For this reason,
There is a need for materials that have a low dielectric constant. In the conventional inductance element as described above, an insulating ceramic such as ferrite is used as a substrate, but its dielectric constant is relatively high, usually about 4 to 5, and it is insufficient as high frequency dielectric characteristics. .

As a material having a low dielectric constant, an insulating synthetic resin or the like has been developed in place of the insulating ceramic material. However, it has a low dielectric constant and good electrical characteristics, and further requires heat resistance of the substrate, adhesiveness with the conductor film, workability, etc., which are required when forming the coil conductor and the terminal portion with a thin film or a thick film. An inductance element using a material having all the items has not been proposed so far.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and improves the induction element that does not depend on the winding as described above to realize small size and high performance. It is another object of the present invention to obtain an inductance element that can be manufactured at low cost.

[0007]

The objects of the present invention can be achieved by the following methods (1) to (7).

(1) An inductance element having a base, a coil conductor, and a terminal portion, which is obtained by polymerizing a monomer composition containing at least fumaric acid diester as a monomer. An inductance element comprising a dielectric polymer material, wherein a coil conductor and a terminal portion are formed of a film having conductivity.

(2) The inductance element according to (1), characterized in that the base is prismatic.

(3) The inductance element according to (1) or (2), wherein the coil conductor is made of a material containing copper or silver as a main component.

(4) The thickness of the coil conductor is 0.5 to
The inductance element according to any one of (1) to (3), which has a thickness of 100 μm.

(5) A manufacturing method for producing an inductance element according to any one of (1) to (4), characterized in that the coil conductor is formed by electroless plating.

(6) The coil conductor is formed by electroless plating and electroplating (1) to
A manufacturing method for manufacturing the inductance element according to any one of (4).

(7) A method of manufacturing an inductance element according to any one of (1) to (4), characterized in that the coil conductor is formed by a thick film method.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The inductance element of the present invention is
A low dielectric polymer material obtained by polymerizing a monomer composition containing at least fumaric acid diester as a monomer (hereinafter referred to as fumarate) is provided with a base, a coil conductor, and a terminal portion. (Referred to as resin).

In addition to high-frequency transmission characteristics and low-dielectric characteristics, which are excellent in performance required for a resin substrate used for an inductance element which is inexpensive and has good workability, heat resistance required in a soldering process and coil manufacturing are required. Adhesion to various conductor films and chemical resistance required in the plating process are essential.

Examples of the polymer material having a low dielectric constant include thermoplastic resins such as polyethylene, polypropylene and polycarbonate and acid-curable epoxy resins. However, the former is inferior in adhesiveness to a conductor film and heat resistance and is insufficient for forming a conductor film on the surface of a substrate, and the latter is slightly better in heat resistance than the former, but the present invention Inferior to fumarate resin.

Further, thermosetting resins such as polyphenylene oxide and diallyl phthalate resins, which are relatively excellent in heat resistance and adhesion to a conductor film, have a relatively high dielectric constant and are therefore insufficient as a substrate for high frequencies. Is. Since the fumarate resin has a sufficiently low relative dielectric constant of about 1.8 to 3.0, as described in detail in Japanese Patent Application No. 8-042072, it is necessary to reduce the electrostatic capacitance and increase the self-resonant frequency. Can extend the frequency characteristic of the Q value and reduce the loss at high frequencies. Further, it has good adhesiveness to a metal material and excellent chemical resistance. This is an important characteristic when forming a conductor film on a substrate, and prevents a conductor film from peeling off from the substrate when forming a coil by forming a good quality conductor film on the substrate and performing laser trimming or cutting. . Further, the resin of the present invention is 2
It has a decomposition temperature of 90 ° C or higher, and satisfies the heat resistant temperature of 230 to 260 ° C required in the soldering process using a reflow furnace or the like.

Since the substrate of the present invention is a polymeric material, it has good moldability and processability. By laser trimming, it is possible to easily manufacture a coil, or to mold or cut a substrate. That is, it becomes possible to manufacture the base body at a lower cost than the base body made of ceramic or the like.

The fumaric acid diester monomer used as a raw material of the fumarate resin used in the present invention is not particularly limited, but the compound represented by the formula (1) is preferable.

[0021]

[Chemical 1]

(In the formula (1), R ₁ represents an alkyl group or a cycloalkyl group, R ₂ represents an alkyl group, a cycloalkyl group or an aryl group, and R ₁ and R ₂ may be the same or different. ) Further, the fumarate resin used in the present invention has the above formula (1)
The polymer may be obtained by polymerizing only the fumaric acid diester monomer represented by the formula (1) or may be copolymerized with the vinyl-based monomer represented by the formula (2).

[0023]

[Chemical 2]

(In the formula (2), X represents a hydrogen atom or a methyl group, and Y represents a fluorine atom, a chlorine atom, an alkyl group, an alkenyl group, an aryl group, an ether group, an acyl group or an ester group.) A method of manufacturing the inductance element of the present invention will be described.

The fumarate resin is processed into a bobbin shape by a known method such as cutting or extrusion. A conductor film is formed on the entire surface of this bobbin by a known film forming technique such as vapor deposition, plating, or thick film method. A coil is formed by spirally forming a groove on the entire surface of the bobbin excluding the terminal portion by machining such as a cutter or laser trimming. After that, a resin or the like is applied to the trimming portion to form a protective layer, and then an electrode portion is formed by electroplating the end portion of the bobbin to obtain an inductance element.

As described above, according to the present invention, it is possible to easily obtain an inductance element by using an inexpensive resin base and without forming a coil by winding.

The shape of the substrate may be various according to the application, but when it is mounted on a printed circuit board or the like, it is preferably a prismatic shape in order to obtain mounting stability.

Further, as the conductor formed on the substrate, it is preferable to use a metal containing copper or silver as a main component because it has a low electric resistivity and good high frequency characteristics. The lower limit of the conductive film at this time is not particularly limited, but is usually about 0.5 μm. When the thickness of the conductor film is less than 0.5 μm, a good high frequency characteristic cannot be obtained due to defects in the conductor film or an increase in the electric resistance value of the conductor film itself.

The upper limit is about 100 μm in the thick film method, but is preferably 50 μm in the ordinary plating method.
m, and more preferably 30 μm. Conductor thickness is 1
If it exceeds 00 μm, distortion occurs in the conductor film and the adhesion between the conductor and the substrate deteriorates. Further, it requires time for cutting or laser trimming. There is also a problem in that the cost for producing the conductor film is increased.

[0030]

【Example】

Example 1 A fumarate resin represented by the formula (1) (a homopolymer of dicyclohexyl fumarate: HDC)
(H, molecular weight: 800,000) is dissolved in toluene and poured into a rectangular container, and toluene is slowly evaporated so that dust and dirt do not enter to form a resin plate having a thickness of 1 mm. This plate was cut into a prismatic shape as shown in FIG. 1 to obtain a bobbin.

Next, the bobbin was plated with copper by electroless plating, and a copper plating layer of 20 μm was formed on the entire surface of the bobbin by electroplating. The plated outer peripheral surface was helically laser-trimmed to form a coil conductor.

The trimmed portion is coated with the same fumarate resin as the substrate to form a protective layer, and then the end portion is subjected to three-layer plating of copper, nickel and tin by electroplating,
The electrode part was produced. As a result, the inductance element shown in FIG. 2 was obtained. In FIG. 2, 1 is a substrate, 2 is a plated film, 3 is a protective layer, and 4 is an end plated layer.

This inductance element is used as an impedance analyzer (HP41
The Q value was measured using (94A) (frequency 100 MHz). Moreover, the self-resonant frequency was measured using a network analyzer (HP8753C) manufactured by Hewlett-Packard Company. After dipping this element in a solder bath at 260 ° C. for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

Example 2 A fumarate resin represented by the formula (1) (a homopolymer of dicyclohexyl fumarate, abbreviated as HDCH, molecular weight: 800,000) was dissolved in toluene and poured into a rectangular container to remove dust and dirt. To avoid this, toluene is slowly evaporated to form a resin plate having a thickness of 1 mm. This plate was cut into a prismatic shape as shown in FIG. 1 to obtain a bobbin.

Next, the electroless plating method and the electroplating method were used together to form a silver plating layer of 10 μm on the entire surface of this bobbin. The plated outer peripheral surface was helically laser-trimmed to form a coil conductor.

The trimmed portion is coated with the same fumarate resin as that of the substrate to form a protective layer, and then the end portion is subjected to three-layer plating of silver, nickel and tin by electroplating,
The electrode part was produced. As a result, an inductance element having the same structure as in Example 1 was obtained.

This inductance element is used as an impedance analyzer (HP41
The Q value was measured using (94A) (frequency 100 MHz). Moreover, the self-resonant frequency was measured using a network analyzer (HP8753C) manufactured by Hewlett-Packard Company. After dipping this element in a solder bath at 260 ° C. for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

Example 3 A fumarate resin represented by the formula (1) (copolymer of dicyclohexyl fumarate and diisopyropyr fumarate: abbreviated name: CDIP, molecular weight: 13)
(0,000) is dissolved in toluene and poured into a rectangular container, and toluene is slowly evaporated to prevent dust and dirt from entering to form a resin plate having a thickness of 1 mm. This plate was cut into a prismatic shape as shown in FIG. 1 to obtain a bobbin.

Next, an electroless plating method and an electroplating method were used together to form a copper plating film of 50 μm on the entire surface of this bobbin. The plated outer peripheral surface was helically laser-trimmed to form a coil conductor.

The trimmed portion is coated with the same fumarate resin as that of the substrate to form a protective layer, and then the end portion is plated with three layers of copper, nickel and tin by electroplating.
The electrode part was produced. As a result, an inductance element having the same structure as in Example 1 was obtained.

This inductance element is used as an impedance analyzer (HP41
The Q value was measured using (94A) (frequency 100 MHz). Moreover, the self-resonant frequency was measured using a network analyzer (HP8753C) manufactured by Hewlett-Packard Company. The results are shown in Table 1.

Example 4 Fumarate resin represented by the formula (1) (copolymer of dicyclohexyl fumarate and diisopyropyr fumarate: abbreviated name: CDIP, molecular weight: 13)
(0,000) is dissolved in toluene and poured into a rectangular container, and toluene is slowly evaporated to prevent dust and dirt from entering to form a resin plate having a thickness of 1 mm. This plate was cut into a prismatic shape as shown in FIG. 1 to obtain a bobbin.

Next, a silver paint was applied to the entire surface of this bobbin by a thick film method to form a conductive coating film of 100 μm. The outer peripheral surface of this coating film was spirally laser-trimmed to form a coil conductor.

The trimmed portion is coated with the same fumarate resin as that of the substrate to form a protective layer, and then the end portion is plated with three layers of copper, nickel and tin by electroplating.
The electrode part was produced. As a result, an inductance element having the same structure as in Example 1 was obtained.

This inductance element is used as an impedance analyzer (HP41
The Q value was measured using (94A) (frequency 100 MHz). Moreover, the self-resonant frequency was measured using a network analyzer (HP8753C) manufactured by Hewlett-Packard Company. After dipping this element in a solder bath at 260 ° C. for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

Comparative Example 1 An inductance element was prepared in the same manner as in Example 1 except that the fumarate resin of Example 1 was replaced with an acid-curable epoxy resin (THPA curing) manufactured by Sumitomo Bakelite Co., Ltd. .

The relative permittivity and Q value of these inductance elements were measured using an impedance analyzer (frequency 100 MHz). The self-resonant frequency was measured using a network analyzer. After dipping this element in a solder bath at 260 ° C. for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

[Comparative Example 2] Instead of the fumarate resin of Example 1, polyphenylene oxide (PP) manufactured by Matsushita Electric Works, Ltd.
O) was used to manufacture an inductance element in the same manner as in Example 1 except for the above.

The relative permittivity and Q value of these inductance elements were measured using an impedance analyzer (frequency 100 MHz). The resonance frequency was measured using a network analyzer. In addition, this element is
After soaking in a solder bath at 0 ° C for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

[Comparative Example 3] An inductance element was prepared in the same manner as in Example 1 except that polycarbonate (PC) manufactured by Mitsubishi Gas Chemical Company was used instead of the fumarate resin of Example 1.

The relative permittivity and Q value of these inductance elements were measured using an impedance analyzer (frequency 100 MHz). The resonance frequency was measured using a network analyzer. In addition, this element is
After soaking in a solder bath at 0 ° C for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1.

Comparative Example 4 An inductance element was prepared in the same manner as in Example 1 except that diallyl phthalate (DAP) made by Asahi Organic Material was used instead of the fumarate resin of Example 1.

The relative permittivity and Q value of these inductance elements were measured using an impedance analyzer (frequency 100 MHz). The resonance frequency was measured using a network analyzer. In addition, this element is
After soaking in a solder bath at 0 ° C for 2 minutes, blisters and discoloration of the appearance were visually observed to evaluate heat resistance. The results are shown in Table 1. The materials listed as comparative examples in Table 1 are materials that are generally used in the past.

[0054]

[Table 1]

In Table 1, a sample having a relative dielectric constant and a Q value of the substrate characteristics of 1 mm square and a length of 120 mm was prepared.
It is a value measured at a frequency of 1 GHz by a dielectric property measuring device (commonly known as a perturbation method) of Japanese Patent Application No. 8-127996.
Also, the self-resonant frequency and Q value of the device are 100MHz.
It is the value measured at the frequency.

The solder heat resistance is evaluated by setting the coil at 260 ° C.
It is soaked in the solder bath of No. 2 for 2 minutes, and blister and discoloration of the appearance are visually judged. O indicates an inductance element in which no abnormality is observed, and X indicates an inductance element in which abnormality is observed.

The device characteristics of Examples 1 and 3 in Table 1 show high self-resonant frequency and Q value of the device regardless of the type of fumarate resin used for the substrate and the thickness of the conductor. On the other hand, although the self-resonance frequency of Comparative Example 1 is almost the same as that of the example, the Q value is inferior, and it is insufficient as a high frequency element. Further, Comparative Examples 2 to 4 using a resin generally used for electronic parts are inferior in self-resonance frequency and Q value, and are not suitable.

Examples 2 and 4 are examples in which the material and thickness of the conductor and the number of turns of the coil are different, and the characteristics as a high-performance inductance element are sufficiently satisfied.

All of the examples are good in terms of soldering heat resistance, while the comparative example is incapable of soldering.
Appropriate processing other than soldering is required. This means that the present invention makes it possible to manufacture a high-efficiency inductance element, which has never been obtained, by a simple method. That is, the present invention has remarkable effects in terms of both improvement of characteristics and cost reduction.

[0060]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the substrate of the inductor having the substrate, the coil conductor, and the terminal portion is obtained by polymerizing the monomer composition containing the fumaric acid diester as a monomer. Industrialized device that is made of dielectric polymer material and that satisfies the requirements of downsizing, high performance, and cost reduction of devices mounted in mobile communication devices by forming coil conductors and terminals with conductive films. It can be produced statically and supplied to the market.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a substrate used for an inductance element of the present invention.

FIG. 2 is a sectional view showing a form of an example of an inductance element of the present invention.

[Explanation of symbols]

1 Inductance element substrate 2 Conductor layer (plating film) 3 protective layer 4 Edge plating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 2-10704 (JP, A) JP-A 3-37257 (JP, A) JP-A 7-297033 (JP, A) JP-A 7- 57936 (JP, A) JP 9-208627 (JP, A) JP 10-189344 (JP, A) JP 8-181019 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 17/00 H01F 27/29

Claims (7)

(57) [Claims] 1. An inductance element comprising a substrate, a coil conductor, and a terminal portion, wherein the substrate has a low dielectric constant obtained by polymerizing a monomer composition containing at least fumaric acid diester as a monomer. An inductance element comprising a conductive polymer material, wherein the coil conductor and the terminal portion are formed of a conductive film. 2. The inductance element according to claim 1, wherein the base has a prismatic shape. 3. The inductance element according to claim 1, wherein the coil conductor is made of a material containing copper or silver as a main component. 4. The coil conductor has a thickness of 0.5 to 100.
μm, any one of claims 1 to 3 characterized in that
Inductance element according to the paragraph. 5. The method for producing an inductance element according to claim 1, wherein the coil conductor is formed by electroless plating. 6. The method for producing an inductance element according to claim 1, wherein the coil conductor is formed by electroless plating and electroplating. 7. The manufacturing method for producing an inductance element according to claim 1, wherein the coil conductor is formed by a thick film method.