JP3283778B2 - Inductance element and wireless terminal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance element and a radio terminal device which are used for electronic equipment such as mobile communication, and particularly suitably used for high frequency circuits and the like.

[0002]

2. Description of the Related Art FIG. 15 is a side view showing a conventional inductance element. In FIG. 15, reference numeral 1 denotes a square-pillar or cylindrical base, 2 denotes a conductive film formed on the base 1, 3 denotes a groove provided in the conductive film 2, and 4 denotes a stacked layer on the conductive film 3 Protected material.

[0003] Such electronic components are adjusted to predetermined characteristics by adjusting the interval between the grooves 3 and the like.

A prior example is disclosed in Japanese Patent Application Laid-Open No. 7-307201.
JP, JP-A-7-297033, JP-A-5-1
JP-A-29133, JP-A-1-238003, JP-A-57-117636, JP-A-5-29925
No. 0, Japanese Unexamined Patent Publication No. 7-297033, and the like.

[0005]

However, in the above configuration, when a high current is applied, the inductance element may generate abnormal heat, and the conductive film 2 may be peeled off, which may cause deterioration of characteristics. Or cause thermal damage to other components, deteriorating the characteristics of the device, so that it cannot be used in a circuit or the like that passes a high current.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an inductance element and a wireless terminal device capable of suppressing deterioration of characteristics and thermal damage of other components.

[0007]

SUMMARY OF THE INVENTION The present invention provides a base and a base.
A conductive film made of copper or a copper alloy
A spiral groove provided in the electrode film, and a length L of the element.
1, when width L2 and height L3, L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm , and a current of 1.2 A was passed. Sometimes the temperature of the conductive film rises
An inductor having a conductive film formed at a temperature of 20 ° C. or less.
A conductive element, such as the width and thickness of the conductive film, and the DC resistance
Was within a predetermined range.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a conductive film made of copper or a copper alloy provided on a base; and a spiral groove provided on the conductive film. Where L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm when the length L1, width L2, and height L3 of the element are defined as: An inductance element in which a conductive film is formed such that the temperature of the conductive film rises to 20 ° C. or less when a current of 1.2 A flows, wherein the width K1 of the groove is 15 μm <K1
<20 μm, the width K2 of the conductive film between the grooves is 100
μm <K2 <200 μm, and the thickness of the conductive film is 50
By setting the thickness to μm or more , the electric resistance of the conductive film can be reduced, and the groove can be formed with high accuracy, and even when the conductive film is formed thick, the groove can be formed reliably. Since the winding part can be formed,
It is possible to prevent deterioration of characteristics due to peeling or fusing of the conductive film due to self-heating, and to suppress thermal damage to other components. Further, since the area for attachment to the substrate can be reduced, the size of the substrate can be reduced, and thus the device can be reduced in size, and further, damage to the elements can be prevented.

According to a second aspect of the present invention, there is provided a base, a conductive film formed on the base, and a screw provided on the conductive film.
A spiral groove, comprising a protective material provided on the groove,
When the length L1, width L2, and height L3 of the element are L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm An inductance element in which a conductive film is formed such that a rise temperature of the conductive film becomes 20 ° C. or less when a current is passed, and the height difference of the unevenness of the protective material is 70%.
μm or less, and the width K2 of the conductive film between the grooves is 10 μm or less.
0 μm <K2 <200 μm, and the thickness of the conductive film is 5
By setting the thickness to 0 μm or more, even if the depth of the groove is increased in order to suppress self-heating, it is possible to suppress the adhesion of an unnecessary substance and the erroneous suction of noise. Further, since the area for attachment to the substrate can be reduced, the size of the substrate can be reduced, and thus the device can be reduced in size, and further, damage to the elements can be prevented.

According to a third aspect of the present invention, there is provided a base, a conductive film formed on the base, and a screw provided on the conductive film.
A spiral groove, and the length L1, width L2, height L3 of the element
L1 = 0.5-1.8 mm L2 = 0.2-1.0 mm L3 = 0.2-1.0 mm When the current is 1.2 A, the temperature of the conductive film rises when An inductance element having a conductive film formed at a temperature of 20 ° C. or lower, wherein the DC resistance of the conductive film is 50 mΩ.
The width K2 of the conductive film between the grooves is set to 100 μm or less.
m <K2 <200 μm, and the thickness of the conductive film is 50 μm.
m or more , self-heating can be reliably suppressed, and the mounting area on the substrate can be reduced.
The size of the substrate can be reduced, and the size of the device can be reduced.
Moreover, breakage of the element and the like can be prevented.

[0011]

According to a fourth aspect of the present invention, in the third aspect, a protective material is provided on the groove provided in the conductive film, and a height difference of the unevenness of the protective material is set to 70 μm or less.
It is possible to suppress the attachment of unnecessary objects and the noise suction error.

[0013]

[0014]

According to a fifth aspect of the present invention, the Q value can be improved by setting the surface roughness of the conductive film to 1.0 μm or less in the first to fourth aspects.

According to a sixth aspect of the present invention, in the first to fifth aspects, the step-down portion is provided in the center of the element, and the depth L4 of the step-down portion is set to 5 μm to 50 μm, so that the protective material is formed. It can be configured to be relatively thick, and can also prevent element breakage and the like.

According to a seventh aspect of the present invention, in the first to sixth aspects, the conductive film is formed by laminating a plurality of conductive films.
The weather resistance and the like of the conductive film can be improved.

[0018] The invention according to claim 8 is a voice signal converting means for converting a voice into a voice signal, an operating means for inputting a telephone number or the like, a display means for displaying an incoming call display, a telephone number or the like, and a voice signal. A wireless terminal device comprising: a transmitting unit that demodulates the signal into a transmission signal; a receiving unit that converts a reception signal into a voice signal; an antenna that transmits and receives the transmission signal and the reception signal; and a control unit that controls each unit. By using the inductance element according to any one of claims 1 to 7 as a filter circuit or a matching circuit constituting a receiving unit and a transmitting unit, or as a part constituting a power module used for a transmitting unit, A large current circuit board or the like can be reduced in size, the size of the device can be reduced, and thermal damage inside the device can be prevented.

Hereinafter, embodiments of the inductance element and the wireless terminal device according to the present invention will be described.

FIGS. 1 and 2 are a perspective view and a side view, respectively, showing an inductance element according to an embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a base which is formed by subjecting an insulating material or the like to press working, extrusion, or the like.
Reference numeral 2 denotes a conductive film provided on the base 11.
2 is formed on the base 11 by an evaporation method such as a plating method or a sputtering method. Reference numeral 13 denotes a groove provided in the base 11 and the conductive film 12. The groove 13 may be formed by irradiating the conductive film 12 with a laser beam or the like.
Is mechanically formed by applying a grindstone or the like to the surface. Reference numeral 14 denotes a protective material applied to a portion of the base 11 and the conductive film 12 where the groove 13 is provided. Reference numerals 15 and 16 denote terminal portions on which terminal electrodes are formed, respectively. A groove 13 and a protection member 14 are provided. In addition, FIG.
FIG. 4 is a diagram in which part of FIG.

The inductance element according to the present embodiment has a practical frequency band corresponding to a high frequency range of 1 to 6 GHz, has a small inductance of 50 nH or less, and has a length L1 and a width L2 of the inductance element. The height L3 is preferably as follows.

L1 = 0.5 to 1.8 mm (preferably 0.6 to 1.6 mm) L2 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
mm) L3 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
(Note that the dimensional error of each of L1, L2, and L3 is 0.3 mm.)
02 mm or less is preferred).

If L1 is less than 0.5 mm, the required inductance cannot be obtained.
It is difficult to form a conductive film (described later) having a thickness of 50 μm or more (preferably 100 μm or more) on the conductive film formed thereon, and it is difficult to reduce the DC resistance of the conductive film to 50 mΩ or less. Is difficult to lower than a predetermined temperature, and good characteristics cannot be obtained. Further, when L1 exceeds 1.8 mm, the element itself becomes large, and it is not possible to reduce the size of a circuit board or the like on which an electronic circuit or the like is formed (hereinafter abbreviated as a circuit board or the like), and as a result, It is not possible to reduce the size of an electronic device or the like on which a circuit board or the like is mounted. If each of L2 and L3 is 0.2 mm or less, the mechanical strength of the element itself becomes too weak, and when mounting on a circuit board or the like with a mounting device,
Element breakage or the like may occur. On the other hand, if L2 and L3 are 1.0 mm or more, the elements become too large, and it is not possible to reduce the size of the circuit board or the like and, consequently, the size of the device. In addition, L4 (depth of step drop) is 5 μm to 50 μm.
μm is preferable, and if it is 5 μm or less, the protective material 14
Must be reduced in thickness, and good protection characteristics cannot be obtained. On the other hand, if L4 exceeds 50 μm, the mechanical strength of the base is weakened, which may also cause element breakage.

With respect to the inductance element configured as described above, each part will be described in detail below. FIG. 3 is a cross-sectional view of a base on which a conductive film is formed, and FIGS. 4A and 4B are a side view and a bottom view of the base, respectively.

First, the shape of the base 11 will be described.
As shown in FIGS. 3 and 4, the base 11 is provided with a central portion 11a having a rectangular cross section and both ends of the central portion 11a so as to be easily mounted on a circuit board or the like. It is constituted by ends 11b and 11c. Although the end portions 11b and 11c and the central portion 11a have a rectangular cross section, they may have a polygonal shape such as a pentagonal shape or a hexagonal shape. The central portion 11a is configured to drop down from the end portions 11b and 11c. In the present embodiment, the end portions 11b, 1
By making the cross-sectional shape of 1c substantially square, the mountability of the inductance element to a circuit board or the like was improved.
Further, in the present embodiment, the groove 13 is provided laterally in the central portion 11a.
Is formed, there is no direction even if it is mounted on a circuit board or the like, so that the handling becomes easy. Further, an element portion (the groove 13 and the protective material 14) is formed in the central portion 11a, and terminal portions 15 and 16 are formed in the end portions 11b and 11c.

In this embodiment, the central portion 11a and the end portions 11b and 11c are both formed in a substantially square shape.
The shape may be a regular polygon such as a regular pentagon. Furthermore, in the present embodiment, the central section 11a and the end sections 11c and 11b have the same cross-sectional shape such as a regular square.
May be different. That is, the cross-sectional shape of the end portions 11b and 11c may be a regular polygonal shape, and the cross-sectional shape of the central portion 11a may be another polygonal shape or a circular shape. Central part 11a
The groove 13 can be formed satisfactorily by making the cross-sectional shape circular.

Further, in the present embodiment, the central portion 11a
By stepping down from the ends 11b and 11c,
When the protective material 14 was applied, contact between the protective material 14 and a circuit board or the like was prevented.
The center part 11a depends on the thickness of the circuit board 4 and the condition of the circuit board or the like to be mounted (a groove is formed in a part where the circuit board or the like is mounted, or an electrode portion of the circuit board or the like is raised).
Need not be dropped. Center 11a to end 11
If the step is not dropped from b and 11c, the structure of the base 11 is simplified, the productivity is improved, and the mechanical strength of the central portion 11a is also improved. Even if you do not let the steps drop like this,
It may be a quadrangular prism having a quadrangular cross section, or a prism having a polygonal cross section.

As shown in FIG. 4A, the heights Z1 and Z2 of the ends of the base 11 preferably satisfy the following conditions.

| Z1-Z2 | ≦ 80 μm (preferably 50 μm) The height difference between Z1 and Z2 is 80 μm (preferably 50 μm).
m or less), when the element is mounted on a circuit board and attached to a circuit board or the like with solder or the like, the element is pulled to one end by surface tension of the solder or the like, and the element stands up. The probability of occurrence is very high. This Manhattan phenomenon is shown in FIG. As shown in FIG. 5, an inductance element is arranged on a substrate 200,
Solder 20 between each of terminal portions 15 and 16 and substrate 200
Although the solders 201 and 202 are provided, when the solders 201 and 202 are melted by reflow or the like, the molten solders 201 and 202 are melted due to a difference in the application amount of each of the solders 201 and 202 and a difference in melting point due to a difference in material. 5 differs between the terminal portion 15 and the terminal portion 16, and as a result, as shown in FIG. 5, one of the terminal portions (the terminal portion 1 in FIG.
5), the inductance element rises. If the difference between the heights of Z1 and Z2 exceeds 80 μm (preferably 50 μm or less), the elements are arranged on the substrate 200 in an inclined state, and the standing of the elements is promoted. In addition, the Manhattan phenomenon occurs remarkably particularly in small and lightweight chip-type electronic components (including a chip-type inductance element), and one of the causes of the Manhattan phenomenon is the difference in height between the terminal portions 15 and 16. It was noted that the device was inclined and was arranged on the substrate 200. As a result, by forming the base 11 by molding or the like so that the difference between the heights of Z1 and Z2 is 80 μm or less (preferably 50 μm or less), the occurrence of the Manhattan phenomenon could be significantly suppressed. . By setting the difference between the heights of Z1 and Z2 to 50 μm or less, the occurrence of the Manhattan phenomenon can be substantially suppressed.

The shape of the base 11 may be cylindrical. The conductive film 12 is formed on the base 11 as described later by making the shape of the base 11 cylindrical.
When a groove is formed in the conductive film 12 by laser processing or the like, the depth and the like of the groove can be accurately formed,
Variations in characteristics can be suppressed. Also, the base 11
When is made cylindrical, it is preferable from the viewpoint of characteristics that the diameter of the central portion of the base 11 be smaller than the diameter of both ends.

Next, the chamfering of the base 11 will be described.
FIG. 6 is a perspective view of a base used for the inductance element according to one embodiment of the present invention. As shown in FIG. 6, each corner 1 of the ends 11 b and 11 c of the base 11 is provided.
The chamfered edges 1e and 11d are preferably formed, and the radius of curvature R1 of the chamfered corners 11e and 11d and the radius of curvature R2 of the corner 11f of the central portion 11a are preferably formed as follows.

0.03 <R1 <0.15 (mm) 0.01 <R2 (mm) If R1 is 0.03 mm or less, the corners 11e and 11d
Since the corners are sharp, the corners 11e and 11d may be chipped due to a slight impact or the like, and the chipping may cause deterioration of characteristics or the like. When R1 is 0.15 mm or more, the corner 11
Since e and 11d are too round, the above-mentioned Manhattan phenomenon is likely to occur, which causes a problem. Furthermore, when R2 is 0.
When the thickness is less than 01 mm, burrs and the like are likely to be generated on the corners 11f, and the thickness of the conductive film 12, which is formed on the central portion 11a and greatly affects the characteristics of the element, differs greatly between the corners 11f and the flat portion. And the variation in element characteristics becomes large.

Next, the constituent materials of the base 11 will be described. It is preferable to satisfy the following characteristics as a constituent material of the base 11.

Volume resistivity: 10 ¹³ or more (preferably 10 ¹⁴ or more) Thermal expansion coefficient: 5 × 10 ⁻⁴ or less (preferably 2 × 10 ⁻⁵ or less) [Coefficient of thermal expansion at 20 ° C. to 500 ° C.] Dielectric constant : 1 or less at 1 MHz (preferably 10 or less) Flexural strength: 1300 kg / cm ² or more (preferably 20
(00 kg / cm ² or more) Density: ^{2 to 5} g / cm ³ (preferably ³ to 4 g / cm ³ ) When the constituent material of the base 11 has a volume resistivity of 10 ¹³ or less, the base 11 together with the conductive film 12 Also, since a current starts to flow in a predetermined manner, a parallel circuit is formed, and the self-resonant frequency f0 and the Q value become low, which is not suitable for a high-frequency element.

If the coefficient of thermal expansion is 5 × 10 ⁻⁴ or more, cracks may occur in the base 11 due to heat shock or the like. In other words, when the thermal expansion coefficient is 5 × 10 ⁻⁴ or more, the laser beam or the grindstone is used when forming the groove 13 as described above. Although cracks and the like may occur, the occurrence of cracks and the like can be largely suppressed by having the above-described coefficient of thermal expansion.

If the dielectric constant is 12 or more at 1 MHz, the self-resonant frequency f0 and the Q value become low, which is not suitable for a high-frequency device.

If the bending strength is 1300 kg / cm ² or less, the element may be broken when mounted on a circuit board or the like by a mounting apparatus.

When the density is 2 g / cm ³ or less, the base 1
1, the water absorption rate is increased, the characteristics of the base 11 are significantly deteriorated, and the characteristics as an element are deteriorated. The density is 5 g / c
If it exceeds m ³ , the weight of the base will be heavy, and there will be a problem in mountability and the like. In particular, when the density is set within the above range, the water absorption rate is small, water hardly enters the base 11, the weight is reduced, and no problem occurs when mounting on a substrate by a chip mounter or the like.

By defining the volume resistivity, the coefficient of thermal expansion, the dielectric constant, the bending strength, and the density of the base 11 as described above, the self-resonant frequency f0 and Q do not decrease. It is possible to suppress the occurrence of cracks or the like in the base 11 due to heat shock or the like, so that the defective rate can be reduced, and furthermore, the mechanical strength can be improved. Since it can be mounted on a circuit board or the like, excellent effects such as improvement in productivity can be obtained.

As a material for obtaining the above-mentioned various properties, there is a ceramic material containing alumina as a main component. However, simply using a ceramic material mainly composed of alumina cannot obtain the above-mentioned characteristics. That is,
Since the above-mentioned various characteristics vary depending on the pressing pressure, the sintering temperature, and the additives at the time of producing the base 11, the production conditions and the like must be appropriately adjusted. Specific manufacturing conditions include a pressing pressure of 2 to 5 tons when processing the base 11, a firing temperature of 1500 to 1600 ° C., and a firing time of 1 to 3 hours. Specific examples of the alumina material include Al ₂ O ₃ of 92 wt% or more, SiO ₂ of 6 wt% or less, MgO of 1.5 wt% or less, and Fe ₂ O ₃ of 0.1 wt% or less.
% Or less, and Na ₂ O of 0.3% by weight or less.

The base 11 may be made of a magnetic material such as ferrite. When the base 11 is made of a magnetic material such as ferrite, an element having high inductance (about 18 nH to 50 nH) can be formed.

Next, the surface roughness of the base 11 will be described. The surface roughness described below means the average roughness of the center line, and the roughness described in the description of the conductive film 12 is also the average roughness of the center line.

The surface roughness of the base 11 is 0.15 to 0.5 μm
m, preferably about 0.2 to 0.3 μm. FIG. 7 is a graph showing the surface roughness of the base 11 and the rate of occurrence of peeling. FIG. 7 shows the results of an experiment as described below. The base 11 and the conductive film 12 were made of alumina and copper, respectively, and samples with various surface roughnesses of the base 11 were prepared, and the conductive film 12 was formed on each sample under the same conditions. Each sample was subjected to ultrasonic cleaning, and thereafter, the surface of the conductive film 12 was observed to determine whether or not the conductive film 12 was peeled. The surface roughness of the base 11 was measured using a surface roughness measuring device (574A, manufactured by Tokyo Seimitsu Surfcom).
The one having a tip R of 5 μm was used. As can be seen from this result, if the average surface roughness is 0.15 μm or less,
The rate of occurrence of peeling of the conductive film 12 formed thereon is about 5%, and good bonding strength between the base 11 and the conductive film 12 can be obtained. Further, if the surface roughness is 0.2 μm or more, peeling of the conductive film 12 hardly occurs. Therefore, if possible, the surface roughness of the base 11 is preferably 0.2 μm or more. Since the peeling of the conductive film 12 is a major factor in deterioration of the characteristics of the element, the rate of occurrence is 5% in terms of yield and the like.
The following is preferred.

FIG. 8 shows the frequency and Q with respect to the surface roughness of the base.
It is a graph which shows the relationship of a value. FIG. 8 shows the results of the following experiment. First, a base 11 having a surface roughness of 0.1 μm or less, a base 11 having a surface roughness of 0.2 to 0.3 μm,
Each sample of the base 11 having a surface roughness of 0.5 μm or more was prepared, and a conductive film of the same material (copper) and the same thickness was formed on each sample. Then, in each sample, the Q value at a predetermined frequency F was measured. As can be seen from FIG. 8, when the surface roughness of the base 11 is 0.5 μm or more, a decrease in the Q value, which is considered to be caused by the deterioration of the film structure of the conductive film 12, is observed. Particularly in the high frequency region, the Q value is significantly deteriorated. The self-resonant frequency f0 (the maximum value of each line) is shifted to the lower frequency side when the surface roughness of the base 11 is 0.5 μm. Therefore, the surface roughness of the base 11 is preferably 0.5 μm or less from the viewpoint of the Q value and the surface of the self-resonant frequency f0.

As described above, judging from the results of both the adhesion strength between the conductive film 12 and the base 11, the Q value of the conductive film, and the self-resonant frequency f0, the surface roughness of the base 11 is 0.15.
μm to 0.5 μm, more preferably 0.2 μm
０．３0.3 μm is good.

It is preferable that the end portions 11b and 11c and the center portion 11a have different average surface roughnesses. That is, the average surface roughness of the end portions 11b and 11c is set in the central portion 1 within the range of 0.15 to 0.5 μm.
It is preferable to make the average surface roughness smaller than 1a.
Since the terminal portions 15 and 16 are formed by laminating the conductive films 12 on the end portions 11b and 11c as described above, the surface roughness of the end portions 11b and 11c is made smaller than that of the central portion 11a, so that the end portions 11b and 11c are formed. Since the surface roughness of the conductive film 12 formed on 11b and 11c can be reduced, the adhesion to electrodes such as a circuit board can be improved, and the inductance element can be securely bonded to the circuit board and the like. it can. Further, a conductive film 12 is laminated on the central portion 11a to form a groove 13
Is formed, so that the conductive film 12 does not come off from the base 11 when the groove 13 is formed by a laser or the like.
Therefore, it is preferable to increase the surface roughness of the central portion 11a rather than the end portions 11b and 11c. In particular, when the groove 13 is formed by laser, the temperature of the portion irradiated with the laser rises more rapidly than other portions, and the conductive film 12 may peel off due to heat shock or the like. Therefore, when the grooves 13 are formed by laser, it is necessary to increase the bonding density between the conductive film 12 and the base 11 as compared with other portions.

As described above, the central portion 11a and the end portions 11b, 11
By making the surface roughness different from that of c, it is possible to prevent the conductive film 12 from peeling off at the time of forming the groove 13 and the adhesion to a circuit board or the like.

In the present embodiment, the bonding strength between the conductive film 12 and the base 11 is improved by adjusting the surface roughness of the base 11.
2 to improve the adhesion strength between the conductive film 12 and the base 11 without adjusting the surface roughness by providing an intermediate layer composed of Cr alone or an alloy of Cr and another metal. Can be. Of course, when the surface roughness of the base 11 is adjusted and the intermediate layer and the conductive film 12 are laminated on the base 11, it is possible to obtain a stronger adhesion strength between the conductive film 12 and the base 11. it can.

Next, the conductive film 12 will be described. The conductive film 12 has a small inductance of 50 nH or less, a Q value of 30 or more for a high frequency signal of 800 MHz or more, and a self-resonant frequency of 1 to 6 GHz.
Those having about z are preferable. In order to obtain the conductive film 12 having such characteristics, a material, a manufacturing method, and the like must be selected.

Hereinafter, the conductive film 12 will be specifically described. Examples of a constituent material of the conductive film 12 include conductive materials such as copper, silver, gold, and nickel. A predetermined element may be added to the material such as copper, silver, gold, and nickel to improve weather resistance and the like. Alternatively, an alloy such as a conductive material and a nonmetallic material may be used. Copper and its alloys are often used as constituent materials in terms of cost, corrosion resistance, and ease of fabrication. When copper or the like is used as the material of the conductive film 12, first, a base film is formed on the base 11 by electroless plating, and a predetermined copper film is formed on the base film by electrolytic plating. The conductive film 12 is formed. Further, when the conductive film 12 is formed of an alloy or the like, it is preferable to form the conductive film 12 by a sputtering method or a vapor deposition method.

Further, in the present embodiment, currents of 1.2 A, 1.6 A, and 2.0 A are supplied to the conductive film 12 so that the temperature rise due to self-heating becomes 20 ° C. or less. The reason why the conductive film 12 is formed in such a manner is that, when the temperature rise exceeds 20 ° C., the conductive film 12 is peeled or melted, and the characteristics of the element are deteriorated. , Width L2, height L3, L1 = 0.5 to 1.8 mm (preferably 0.6 to 1.6 mm)
mm) L2 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
mm) L3 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
(Note that the dimensional error of each of L1, L2, and L3 is 0.3 mm.)
It is preferably equal to or less than 02 mm. Since the inductance element having the size of (2) is generally mounted on a very small substrate (such as a power module) and is used in a circuit for flowing a large current, other electronic components are arranged near the inductance element. This is because it has been found that the heat generated in the inductance element may cause thermal damage to other electronic components, which may cause the characteristics and deterioration of the device. Groove 1
3 is the temperature of the portion of the conductive film 12 forming 3. This rising temperature is measured by a resistance method or a non-contact infrared temperature measuring device.

In the resistance method, for example, the inductance element is left at room temperature (20 ° C.), and a predetermined current is passed through the inductance element for 10 to 15 minutes. At this time, it is preferable to take care that the airflow or the like does not hit the element as much as possible so as not to lower the element temperature. After a current is passed through the inductance element for a predetermined time, the resistance value of the inductance element is measured. In general, when a predetermined metal and a film thickness of the metal are specified, the relationship between the resistance value of the conductive film 12 of the inductance element and the temperature of the conductive film 12 has a predetermined relationship. By measuring, the temperature due to self-heating of the conductive film can be measured.

When an infrared temperature measuring device is used, the inductance element is left at room temperature (20 ° C.), for example, and a predetermined current is passed through the inductance element for 10 to 15 minutes in the same manner as described above. At this time, it is preferable to take care that the airflow or the like does not hit the element as much as possible so as not to lower the element temperature. After a current is passed through the inductance element for a predetermined time, infrared rays generated from the element surface (the surface of the protective material 14) are sensed by an infrared temperature measuring device,
Temperature can be measured. When the infrared temperature measuring device is used, since the surface of the protective material 14 is not measured, it is assumed that the temperature is almost the same as that of the conductive film 12 although some errors occur.

As described above, 1.2A, 1.
As a method of forming a current of 6 A or 2.0 A so that the temperature rise due to self-heating becomes 20 ° C. or less, for example, copper, an alloy of copper, and a trace amount of impurities are mixed in copper as the conductive film 12. When a conductive material is used,
Is preferably 50 μm or more. At this time, since the characteristics of the conductive film 12 to be formed may be different depending on the conditions for forming the conductive film 12, the components of the constituent materials, and the like, it is preferable to make some adjustments.

Further, as another example, a film may be formed from a material containing copper alone or a material containing copper as a main component, and a film made of gold or the like having a lower electric resistance may be further stacked close to the film.

In the above embodiment, by forming the DC resistance of the conductive film 12 to be 50 mΩ or more, self-heating can be surely suppressed and a rise in temperature can be reduced.

Further, as in the present embodiment, when the conductive film 12 is made of, for example, copper or the like and its thickness is increased to suppress self-heating (see FIG. 9), the groove formed in the conductive film 12 is formed. 1
3 and the width K2 of the conductive film 12 between the grooves 13
Preferably have the following relationship:

20 μm>K1> 15 μm 200 μm>K2> 100 μm In particular, as described above, the length L1, width L2, and height L3 are L1 = 0.5 to 1.8 mm (preferably 0.6 to 1.6 mm).
mm) L2 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
mm) L3 = 0.2 to 1.0 mm (preferably 0.3 to 0.8)
(Note that the dimensional error of each of L1, L2, and L3 is 0.3 mm.)
It is preferably equal to or less than 02 mm. In the case of the inductance element described in (1), by setting the above K1 and K2 within the above ranges, the electric resistance can be reduced and the groove 13 formed in the conductive film 12 can be formed with high accuracy. In addition, when the thickness of the conductive film 12 is further increased, the groove 13 can be surely formed.

The conductive film 12 may be composed of a single layer, but may have a multilayer structure. That is, a plurality of conductive films having different constituent materials may be stacked. For example, first, a copper film is formed on the base 11, and then a metal film having good weather resistance (such as nickel) is laminated thereon, so that corrosion of copper, which is somewhat problematic in weather resistance, can be prevented. .

The method for forming the conductive film 12 includes a plating method (such as an electrolytic plating method and an electroless plating method), a sputtering method, and a vapor deposition method. Among these forming methods,
A plating method with good mass productivity and small variations in film thickness is often used.

The surface roughness of the conductive film 12 is preferably 1 μm or less, more preferably 0.2 μm or less. When the surface roughness of the conductive film 12 exceeds 1 μm, the Q value at high frequencies decreases due to the skin effect. FIG. 10 is a graph showing the relationship between the frequency of the conductive film 12 and the Q value. FIG. 10 was derived through the following experiment. First, a conductive film 12 made of copper is formed on a base 11 having the same size and the same material with the same surface roughness while changing the surface roughness. Was measured.
As can be seen from FIG. 10, the surface roughness of the conductive film 12 is 1 μm.
Above this, it can be seen that the Q value in the high frequency region is low. Further, it can be seen that when the surface roughness of the conductive film 12 is 0.2 μm or less, the Q value particularly in a high frequency region is extremely high.

As described above, the surface roughness of the conductive film 12 is 1.
The thickness is preferably 0 μm or less, and more preferably 0.2 μm or less, the skin effect of the conductive film 12 can be reduced, and the Q value particularly at high frequencies can be improved.

Further, the adhesion strength between the conductive film 12 and the base 11 is as follows:
After leaving the base 11 on which the conductive film 12 is formed at a temperature of 400 ° C. for a few seconds, it is preferable that the conductive film 12 be separated from the base 11 by a degree or more. When the element is mounted on a substrate or the like, a temperature of 200 ° C. or more may be applied to the element due to self-heating or heat from other members. Therefore, the conductive film 12 from the base 11 at 400 ° C.
If the adhesion strength is such that no peeling occurs, even if heat is applied to the element, the characteristics of the element do not deteriorate.

Next, the protective member 14 will be described. As the protective material 14, an organic material having excellent weather resistance, for example, an insulating material such as an epoxy resin is used. Further, it is preferable that the protective material 14 has a transparency such that the condition of the groove 13 can be observed. Further, it is preferable that the protective material 14 has a predetermined color while having transparency. The protective material 14 is made of a conductive film 12 such as red, blue, or green, or a terminal 1.
By coloring different colors such as 5, 16 and the like, it is possible to distinguish each element part, and to easily inspect each element part. In addition, by changing the color of the protective material 14 depending on the size, characteristics, product number, and the like of the element, it is possible to reduce errors such as mounting an element having a different characteristic, product number, and the like on an erroneous portion.

As shown in FIG. 11, the protective member 14 has a length Z1 between the corner 13a of the groove 13 and the surface of the protective member 14.
Is preferably 5 μm or more. Z
When 1 is smaller than 5 μm, it is conceivable that characteristic deterioration, discharge, and the like are likely to occur, and the characteristics of the element are significantly deteriorated.
In addition, the corner 13a of the groove 13 is a portion where discharge or the like is particularly likely to occur, and it is highly preferable that a protective material 14 having a thickness of 5 μm or more is formed on the corner 13a. In some cases, after the protective material 14 is formed, plating is performed again to form an electrode film or the like. However, if the protective material 14 having a thickness of 5 μm or more is not formed on the corners 13a, the electrode film or the like may adhere. Thus, an electrode film or the like is formed on the protective material 14 in which the characteristics are deteriorated, and the characteristics are deteriorated.

When the conductive film 12 is formed thick as in this embodiment to suppress self-heating and the like, the groove 13
May become very deep, and irregularities may be formed on the protective material 14. For example, as described above, when the conductive film 12 is made of a material such as copper and the film thickness is 50 μm or more,
The depth of the groove 13 reaches about 80 μm to 100 μm,
At this time, if the protection member 14 is formed on the groove 13, a large step may be generated in the protection member 14. As a result of studying this phenomenon in detail, if the unevenness is very large, unnecessary objects will accumulate in the unevenness, and the unnecessary objects will fall on the board due to the impact when mounting on a board etc. Or
Similarly, when mounting on a substrate or the like, the protective material 14 is sucked by the nozzle, but if the unevenness is extremely large as described above, the nozzle may not be able to be sucked, and the reliability of mounting may not be obtained. I understood. Thus, it has been found that if the step K3 of the unevenness shown in FIG. 9 is set to 70 μm or less (preferably 50 μm or less), it is possible to suppress the adhesion of unnecessary substances and the suction error of the nozzle with a considerable probability. As a method of reducing the unevenness having a large step, for example, there is a method of applying a protective material twice. In this method, first, a protective material 14 is applied thinly, the protective material 14 is embedded in the groove 13, and then the protective material 14 is applied again on the applied protective material 14. In this way, even if the thickness of the conductive film 12 is increased and the groove 13 is formed deep by devising a method of applying the protective material 14 or the like, a large step (K3 of 7
(0 μm or less) No irregularities are formed on the protective material 14.

Next, the terminals 15 and 16 will be described.
Although the terminal portions 15 and 16 function satisfactorily even with the conductive film 12 alone, it is preferable that the terminal portions 15 and 16 have a multilayer structure in order to adapt to various environmental conditions and the like.

FIG. 12 is a sectional view of the terminal portion 15. FIG.
2, a conductive layer 12 is formed on the end 11b of the base 11, and a protective layer 30 made of a weather-resistant material such as nickel or titanium is formed on the conductive layer 12.
0 is formed, and a bonding layer 301 made of solder or the like is formed on the protective layer 300. Protective layer 3
00 can improve the bonding strength between the bonding layer and the conductive film 12 and the weather resistance of the conductive film. In the present embodiment, at least one of nickel and a nickel alloy is used as a constituent material of the protective layer 300, and the bonding layer 301 is used.
Was used as a constituent material. The thickness of the protective layer 300 (nickel) is preferably 2 to 7 μm, and if the thickness is less than 2 μm, the weather resistance is deteriorated.
The electrical resistance of (nickel) itself increases, and the element characteristics deteriorate significantly. The thickness of the bonding layer 301 (solder) is 5
When the thickness is less than 5 μm, a solder erosion phenomenon occurs, and good bonding between the element and a circuit board cannot be expected. When the thickness exceeds 10 μm, the Manhattan phenomenon easily occurs, and the mountability is extremely low. Worse.

The inductance element constructed as described above has no characteristic deterioration and has very good mountability and productivity.

A method of manufacturing the inductance element having the above-described configuration will be described below.

First, the base 11 is manufactured by press molding or extrusion of an insulating material such as alumina. Next, a conductive film 12 is formed on the entire base 11 by a plating method, a sputtering method, or the like. Next, a spiral groove 13 is formed in the base 11 on which the conductive film 12 is formed. The groove 13 is formed by laser processing or cutting. Since the laser processing has very high productivity, the laser processing will be described below. First, the base 11 is mounted on a rotating device, the base 11 is rotated, and a laser is applied to the central portion 11a of the base 11 to remove both the conductive film 12 and the base 11, thereby forming a spiral groove. I do. As the laser at this time, a YAG laser, an excimer laser, a carbon dioxide laser, or the like can be used. The laser beam is focused on the central portion 11a of the base 11 by narrowing the laser beam with a lens or the like.
Further, the depth and the like of the groove 13 can be adjusted by adjusting the power of the laser, and the width and the like of the groove 13 can be adjusted by exchanging a lens when narrowing down the laser beam. Further, since the laser absorptance varies depending on the constituent material of the conductive film 12 and the like, the type of laser (wavelength of the laser) depends on the constituent material of the conductive film 12.
It is preferable to select an appropriate one.

After the groove 13 is formed, the protective material 14 is applied to the portion where the groove 13 is formed (the central portion 11) and dried.

At this point, the product is completed, but a nickel layer or a solder layer may be laminated particularly on the terminal portions 15 and 16 to improve the weather resistance and the joining property. The nickel layer and the solder layer are formed on a semi-finished product on which the protective material 14 is formed by a plating method or the like.

In this embodiment, the inductance element has been described. However, the same effect can be obtained with an electronic component in which a conductive film is formed on a base made of an insulating material.

FIGS. 13 and 14 are a perspective view and a block diagram, respectively, showing a wireless terminal device according to an embodiment of the present invention. 13 and 14, reference numeral 29 denotes a microphone for converting a voice into a voice signal, 30 denotes a speaker for converting a voice signal into a voice, 31 denotes an operation unit including dial buttons and the like, and 32 denotes a display unit for displaying an incoming call and the like. Reference numeral 33 denotes an antenna, and reference numeral 34 denotes a transmission unit for demodulating an audio signal from the microphone 29 and converting it into a transmission signal. The transmission signal produced by the transmission unit 34 is emitted to the outside through the antenna. A receiving unit 35 converts a received signal received by the antenna into an audio signal.
Is converted to voice. 36 is a transmitting unit 34 and a receiving unit 3
5, a control unit for controlling the operation unit 31 and the display unit 32;

Hereinafter, an example of the operation will be described. First, when there is an incoming call, the receiving unit 35 sends the
The control unit 36 displays a predetermined character or the like on the display unit 32 based on the incoming signal,
Further, when a button or the like for receiving an incoming call is pressed from the operation unit 31, a signal is sent to the control unit 36, and the control unit 36
Set each part to the incoming call mode. That is, the signal received by the antenna 33 is converted into an audio signal by the receiving unit 35, and the audio signal is output from the speaker 30 as audio.
The voice input from the microphone 29 is converted into a voice signal, and is transmitted to the outside via the transmitting unit 34 and the antenna 33.

Next, the case of making a call will be described. First, when transmitting a signal, a signal indicating that the signal is transmitted from the operation unit 31 is input to the control unit 36. Subsequently, when a signal corresponding to the telephone number is transmitted from the operation unit 31 to the control unit 36, the control unit 36 transmits a signal corresponding to the telephone number from the antenna 33 via the transmission unit 34. When communication with the other party is established by the transmission signal, a signal to that effect is sent to the control unit 36 through the reception unit 35 via the antenna 33, and the control unit 36 sets each unit to the transmission mode. That is, the signal received by the antenna 33 is converted into an audio signal by the receiving unit 35, the audio signal is output as audio from the speaker 30, and the audio input from the microphone 29 is converted into an audio signal, Through the antenna 33 to the outside.

The inductance element described above (FIG. 1)
12 to FIG. 12) are used for a high-current power module used for a filter circuit, a matching circuit, a power supply, and the like in the transmission unit 34 and the reception unit 35, and the number thereof is one wireless terminal. About several to forty devices are used in the apparatus. By using the inductance element as described above, a substrate or the like used in the device and constituting a circuit or the like through which a large current flows can be reduced in size, so that thermal damage to other portions can be reduced, Stable characteristics of the device can be obtained. Further, the size of the apparatus can be reduced.

The present invention relates to a base, and a copper or metal plate provided on the base.
Or a conductive film formed of a copper alloy and
A spiral groove, and the element has a length L1, a width L2, and a height L
3, L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm , and the temperature rise of the conductive film when a current of 1.2 A flows.
An inductor having a conductive film formed at a temperature of 20 ° C. or less.
A conductive element, such as the width and thickness of the conductive film, and the DC resistance
By was within a predetermined range, even if a large current flows,
The deterioration of the characteristics of the element can be prevented, and thermal damage to other components can be suppressed.

Further, in the wireless terminal device, by mounting the above-described inductance element, the size of the substrate and the like used inside the device can be reduced, so that the device can be reduced in size, and the thermal characteristics of other components can be reduced. As a result, it is possible to suppress deterioration of performance and characteristics of the apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an inductance element according to an embodiment of the present invention.

FIG. 2 is a side view showing the inductance element according to the embodiment of the present invention;

FIG. 3 is a cross-sectional view of a base on which a conductive film used for an inductance element according to an embodiment of the present invention is formed.

FIG. 4 is a diagram showing a base used for an inductance element according to one embodiment of the present invention;

FIG. 5 is a side view showing the Manhattan phenomenon.

FIG. 6 is a perspective view of a base used for the inductance element according to the embodiment of the present invention.

FIG. 7 is a graph showing the surface roughness and the rate of occurrence of peeling of a base used for an inductance element according to an embodiment of the present invention.

FIG. 8 is a graph showing a relationship between a frequency and a Q value with respect to a surface roughness of a base used for an inductance element according to an embodiment of the present invention.

FIG. 9 is a partially enlarged view showing an inductance element according to one embodiment of the present invention.

FIG. 10 is a graph showing a relationship between frequency and Q value with respect to surface roughness of a conductive film used for an inductance element according to one embodiment of the present invention.

FIG. 11 is a side view of a portion provided with a protective material for an inductance element according to an embodiment of the present invention.

FIG. 12 is a sectional view of a terminal portion of the inductance element according to the embodiment of the present invention;

FIG. 13 is a perspective view showing a wireless terminal device according to one embodiment of the present invention;

FIG. 14 is a block diagram showing a wireless terminal device according to an embodiment of the present invention;

FIG. 15 is a side view showing a conventional inductance element.

[Explanation of symbols]

 Reference Signs List 11 base 11a central part 11b, 11c end part 11d, 11e, 11f corner part 12 conductive film 13 groove 14 protective material 15, 16 terminal part 30 speaker 31 operation part 32 display part 33 antenna 34 transmission part 35 reception part 36 control part

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Noriya Sato 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 88123 (JP, A) JP-A-8-181012 (JP, A)

Claims (8)

(57) [Claims] 1. A base, and copper or copper provided on the base.
A conductive film formed of an alloy ; and a spiral groove provided in the conductive film.
L1 = 0.5-1.8 mm L2 = 0.2-1.0 mm L3 = 0.2-1.0 mm When the current is 1.2 A, the temperature of the conductive film rises when An inductance element having a conductive film formed at a temperature of 20 ° C. or less, wherein the width K1 of the groove is set to 15 μm <K1
<20 μm, the width K2 of the conductive film between the grooves is 100
μm <K2 <200 μm, and the thickness of the conductive film is 50
An inductance element having a thickness of at least μm . 2. A device comprising: a base; a conductive film formed on the base; a spiral groove provided in the conductive film; and a protective material provided on the groove. Length L1, width L
2. When the height is L3, L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm, and is conductive when a current of 1.2 A flows. An inductance element in which a conductive film is formed such that the temperature of the film becomes 20 ° C. or less, and the height difference between the unevenness of the protective material is 70%.
μm or less, and the width K2 of the conductive film between the grooves is 10 μm or less.
0 μm <K2 <200 μm, and the thickness of the conductive film is 5
An inductance element having a thickness of 0 μm or more . 3. A device comprising: a base; a conductive film formed on the base; and a spiral groove provided in the conductive film. When L1 = 0.5 to 1.8 mm L2 = 0.2 to 1.0 mm L3 = 0.2 to 1.0 mm, the temperature rise of the conductive film is 20 ° C. when a current of 1.2 A is passed. An inductance element having a conductive film formed as described below, wherein the DC resistance of the conductive film is 50 mΩ.
The width K2 of the conductive film between the grooves is set to 100 μm or less.
m <K2 <200 μm, and the thickness of the conductive film is 50 μm.
m or more . 4. The inductance element according to claim 3, wherein a protective material is provided on the groove provided in the conductive film, and a height difference of the unevenness of the protective material is set to 70 μm or less. 5. A method according to claim 1-4 inductance element as claimed in any one, characterized in that the surface roughness of the conductive film was 1.0μm or less. 6. The inductance element according to claim 1, wherein a stepped portion is provided at a central portion of the element, and a depth L4 of the stepped portion is set to 5 μm to 50 μm. 7. The inductance element as claimed in any one claims 1 to 6 for the conductive film, characterized by being configured by stacking a plurality. 8. A voice signal conversion means for converting voice into a voice signal, an operation means for inputting a telephone number and the like, a display means for displaying an incoming call display, a telephone number and the like, and a demodulation of a voice signal into a transmission signal. A transmitting unit for converting, a receiving unit for converting a received signal into an audio signal, an antenna for transmitting and receiving the transmitted signal and the received signal, and a wireless terminal device including a control unit for controlling each unit; A wireless terminal device using the inductance element according to any one of claims 1 to 7 as a component constituting a filter circuit or a matching circuit constituting a transmitting unit, or a power module used in the transmitting unit.