JP3297638B2 - 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]

FIG. 18 is a side view showing a conventional inductance element. In FIG. 18, reference numeral 1 denotes a square 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 layer formed 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, with the above configuration, a high inductance cannot be realized, and the applicable range of the element cannot be widened.
Further, if the number of turns is increased unnecessarily in order to realize a high inductance, disconnection or the like occurs, and the yield is extremely deteriorated.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide an inductance element and a wireless terminal device which can realize a high inductance and can improve a production yield.

[0007]

The present invention mainly comprises alumina.
Surface roughness provided on a base made of material
Conductive film having a thickness of 1 μm or less, and a spa
With an annular groove, length L1, width L2, height L3
L1 = 0.5 to 2.1 mm L2 = 0.2 to 1.5 mm L3 = 0.2 to 1.5 mm
An inductance element having a
A film thickness of 5 to 20 μm and a winding portion of the conductive film
And the winding density of 15 turns / mm to 50 turns / mm
I, The surface roughness of the base is 0.15 μm to 0.5 μm
Was.

[0008]

The invention according to claim 1 includes a base made of a material containing alumina as a main component, a conductive film provided on the base and having a surface roughness of 1 μm or less. A spiral groove provided in the conductive film;
1, width L2 and height L3: L1 = 0.5 to 2.1 mm L2 = 0.2 to 1.5 mm L3 = 0.2 to 1.5 mm, and 55 nH An inductance element having the above inductance, wherein the film thickness of the conductive film is 5 to 20 μm and the winding density of the winding portion of the conductive film is 15 turns / mm to 50 turns / mm. By setting the surface roughness of the base to 0.15 μm to 0.5 μm, it is possible to have a small size, cope with a high frequency and to have a high inductance, and to prevent a trouble such as disconnection from occurring and to mass production. It becomes excellent configuration, yet can be extremely reduced leakage occurrence rate, further or DC resistance is increased, it is possible to prevent the Q value is deteriorated, further
Can improve the adhesion strength between the conductive film and the base.
Can Ru.

[0009]

[0010] According to a second aspect of the present invention, in the first aspect, a protective material for covering the groove is provided, and a difference in unevenness of the protective material is reduced by seven.
By setting the thickness to 0 μm or less, it is possible to prevent a suction error of the nozzle and prevent deterioration of characteristics.

According to a third aspect of the present invention, in the second aspect , a step is provided in the center of the element, the depth of the step is 5 to 50 μm, and a groove and a protective material are provided in the step. by the, the mechanical strength in the weak Kusezu, it is possible to obtain a good protective properties since the protective member can be provided thick enough.

According to a fourth aspect of the present invention, in the first to third aspects, when the width of the conductive film sandwiched between the grooves is P5 and the width of the groove itself is P6, the value of P5 ÷ P6 is 0. .85-1.
By being 1, the DC resistance can be prevented from increasing and the Q value can be prevented from deteriorating.

According to a fifth aspect of the present invention, there is provided a voice signal converting means for converting a voice into a voice signal, an operating means for inputting a telephone number and the like, a display means for displaying an incoming call display and a telephone number and the like, A wireless terminal device comprising: a transmitting unit that demodulates and converts 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 4 as an element for removing noise, a very small element having high inductance, small size, little deterioration of Q value, and Since noise can be removed, the size and weight of the device can be reduced.

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.

Further, the inductance element of the present embodiment preferably has a high inductance of 55 nH or more, and the length L1, width L2, and height L3 of the inductance element are preferably as follows.

L1 = 0.5 to 2.1 mm (preferably 0.6 to 1.8 mm) L2 = 0.2 to 1.5 mm (preferably 0.2 to 1.0 mm)
mm) L3 = 0.2 to 1.5 mm (preferably 0.2 to 1.0 mm)
(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. Further, if L1 exceeds 2.1 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). 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 1.5 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 furthermore, 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 used for an inductance element according to one embodiment of the present invention is formed, and FIG. 4 is a view showing a base used for the inductance element according to one embodiment of the present invention. .

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 difference in height 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. FIG. 5 shows a side view of the Manhattan phenomenon. FIG.
As shown in FIG. 7, an inductance element is arranged on a substrate 200, and solders 201 and 202 are provided between the terminal portions 15 and 16 and the substrate 200. When the solders 201 and 202 are melted by reflow or the like, Solder 201,
The melted solders 201 and 20 are caused by the difference in the application amount of each of the solders 202 and the difference in the melting point due to the different materials.
The surface tension of 2 differs between the terminal portion 15 and the terminal portion 16, and as a result, as shown in FIG. 5, the terminal device rotates around one terminal portion (the terminal portion 15 in FIG. 5) and the inductance element rises. . The difference in height between Z1 and Z2 is 80 μm
If it exceeds (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, the difference between the heights of Z1 and Z2 is 80 μm.
By forming the base 11 by molding or the like so as to be not more than m (preferably not more than 50 μm), the occurrence of the Manhattan phenomenon could be largely suppressed. Z1 and Z
By setting the difference between the heights 2 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 less than 0.03 mm, 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 Ωm or more (preferably 10 ¹⁴ Ωm or more) Thermal expansion coefficient: 5 × 10 ⁻⁴ / ° C. or less (preferably 2 × 10
⁻⁵ / ° C. or less) [Coefficient of thermal expansion at 20 ° C. to 500 ° C.] Relative permittivity: 12 or less at 1 MHz (preferably 10
Bending strength: 1300 kg / cm ² or more (preferably 20
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 Ωm or less, the conductive material 12 and the base 11 Also, a current starts to flow in a predetermined manner, so that a parallel circuit is formed, and the self-resonant frequency f0 and the Q value decrease, which is not suitable for a high-frequency element.

If the coefficient of thermal expansion is 5 × 10 ⁻⁴ / ° C. or more, cracks may occur in the base 11 due to heat shock or the like. That is, when the thermal expansion coefficient is 5 × 10 ⁻⁴ / ° C. or more, the base 11 is locally heated to a high temperature because a laser beam or a grindstone is used when forming the groove 13 as described above. Although cracks and the like may occur in 11, the occurrence of cracks and the like can be greatly 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, so that the base 11 can be used as a high-frequency element. 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 characteristics, a ceramic material containing alumina as a main component can be used. 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. If the base 11 is made of a magnetic material such as ferrite, an element having a higher inductance 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 and the rate of occurrence of peeling of the base 11 used for the inductance element according to one embodiment of the present invention. FIG. 7 shows the results of an experiment as described below. The base 11 and the conductive film 12 are made of alumina and copper, respectively. Samples with various surface roughnesses of the base 11 are prepared, and the conductive film 1 is formed on each sample under the same conditions.
2 was formed. Each sample was subjected to ultrasonic cleaning, and then the surface of the conductive film 12 was observed.
The presence or absence of peeling was measured. The surface roughness of the base 11 was measured using a surface roughness measuring device (574A, manufactured by Tokyo Seimitsu Surfcom Co., Ltd.) and the tip R was 5 μm. As can be seen from this result, when the average surface roughness is 0.15 μm or less, the occurrence rate of peeling of the conductive film 12 formed on the base 11 is about 5%, and the good base 11 The bonding strength of the 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 device, the occurrence rate is preferably 5% or less from the viewpoint of yield and the like.

FIG. 8 is a graph showing the relationship between the frequency and the Q value with respect to the surface roughness of the base used for the inductance element according to one embodiment of the present invention. FIG. 8 shows the results of the following experiment. First, each sample of the base 11 having a surface roughness of 0.1 μm or less, the base 11 having a surface roughness of 0.2 to 0.3 μm, and the base 11 having a surface roughness of 0.5 μm or more was prepared. Then, a conductive film having the same thickness and the same material (copper) 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, the surface roughness of the base 11 is 0.5 μm.
If it is more than m, 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. Also, the self-resonant frequency f0 (maximum value of each line) has a surface roughness of 0.5
Those of μm are shifted to the lower frequency side. 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-resonance 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 that the surface roughness of the central portion 11a is larger than that of the end portions 11b and 11c because the adhesion strength between the base 11 and the base 11 must be improved. 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. In order to obtain a high inductance of 55 nH or more as the conductive film 12 and prevent deterioration of the self-resonant frequency and the Q value,
Materials and manufacturing methods 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.

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. .

Examples of the method for forming the conductive film 12 include 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.

Next, the thickness of the conductive film 12 will be described with reference to FIG. FIG. 9 is a graph showing a relationship between the film thickness of the conductive film 12 used for the inductance element and the leak rate according to one embodiment of the present invention. The leak rate means that when the groove 13 is formed, burrs are generated in the conductive film 12 at the boundary between the groove 13 and the conductive film 12, and the burrs contact the adjacent conductive film 13 across the groove 13. That is, the degree to which defective products that the adjacent conductive films 13 come into contact with each other are generated. That is, the leak rate 10
% Means that, when 100 inductance elements are manufactured, the above-described leak failure occurs in 10 inductance elements. In particular, when an element having a high inductance is manufactured as in the present embodiment, the width of the groove 13 is necessarily reduced.
It is necessary to increase the number of turns of the conductive film 13, and a defect due to the leakage is remarkably generated. Therefore, it is a problem to reduce the leakage occurrence rate. Here, the relationship between the film thickness of the conductive film 12 and the leak occurrence rate will be described with reference to FIG.
When the film thickness of the conductive film 12 is 27 μm or less, the leak rate becomes 10% or less, and sufficient production efficiency that can withstand practical use can be obtained. The conductive film 12 has a thickness of 20 μm.
If it is less than 5%, the leak occurrence rate becomes 5% or less, and it is understood that there is an extremely excellent effect.

Therefore, as an inductance element having a high inductance, the thickness of the conductive film 12 is 20
It can be seen that μm or less is best. Considering that the DC resistance is not so large and the Q value is not deteriorated, the thickness of the conductive film 12 is preferably 5 μm or more. That is, the thickness of the conductive film 12 of the inductance element having a high inductance is 5 μm to 2 μm.
It is preferable to set it to 0 μm.

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 and the Q value of the conductive film 12 used for the inductance element according to one embodiment of the present invention. FIG.
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, when the surface roughness of the conductive film 12 is 1 μm or more, the Q value in the high frequency region is low. Further, the surface roughness of the conductive film 12 is set to 0.
It can be seen that the Q value particularly in the high frequency region is extremely high when the thickness is 2 μm or less.

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 protection member 14 has a length Z1 between the corner 13a of the groove 13 and the surface of the protection 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 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. By devising a method of applying the protective material 14 in this way, for example, the thickness of the conductive film 12 is increased,
Is formed deeply, the unevenness having a large step (K3 is 70 μm or less) is not 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 of the inductance element according to one embodiment of the present invention. FIG.
5, a conductive layer 12 is formed on an end 11b of a base 11, and a protective layer 300 made of a weather-resistant material such as nickel or titanium is formed on the conductive layer 12.
Is formed, and a bonding layer 301 made of solder or the like is formed on the protective layer 300. Protective layer 30
0 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 solder is used as a constituent material of the bonding layer 301. The thickness of the protective layer 300 (nickel) is preferably from 2 to 7 μm, and if it is less than 2 μm, the weather resistance is deteriorated. The thickness of the bonding layer 301 (solder) is 5 μm.
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 very low. become worse.

Next, the width of the groove 13 and the width of the conductive film 12 sandwiched between the grooves 13 will be described. FIG. 15 is a partially enlarged view showing an inductance element according to one embodiment of the present invention. In FIG. 15, P4 is the conductive film 12 as described above.
And P4 is preferably 5 μm to 20 μm. P5 is the width of the groove 13 and the width of the conductive film sandwiched between the grooves 13, and P6 is the width of the groove 13 itself. Where C = (P5 ÷
P6) is defined.

FIG. 16 is a graph showing the relationship between C and DC resistance of the inductance element according to the embodiment of the present invention. As can be seen from FIG. 16, when C is 0.85 or more,
It can be seen that the DC resistance sharply decreases, and that C is preferably 0.85 or more. FIG. 17 is a graph showing the relationship between the C value and the Q value of the inductance element according to the embodiment of the present invention. As can be seen from FIG. 17, when C is 1.1 or more, the Q value is suddenly deteriorated, and the element is inefficient. Therefore, it is understood that C is preferably set to 0.85 to 1.1 in terms of DC resistance and Q value.

The conductive film 1 sandwiched between the grooves 13
The winding density of the winding part 2 is preferably 15 turns / mm to 50 turns / mm. If the winding density is 15 turns / mm or less, high inductance cannot be obtained. If the winding density is 50 turns / mm or more, disconnection or the like will occur and the manufacturing cost will be reduced. With such a configuration, an inductance element having a high inductance of 55 nH or more can be obtained.

In particular, the length L of the inductance element
1, when the width L2 and the height L3, L1 = 1.5 to 1.7 mm L2 = 0.7 to 0.9 mm L3 = 0.7 to 0.9 mm In
The winding density is preferably 18 turns / mm to 50 turns / mm. With such a structure, an element having a high inductance of 120 nH or more can be realized, and furthermore, disconnection and the like can be prevented.

When the length L1, width L2, and height L3 of the inductance element are L1 = 0.9 to 1.1 mm L2 = 0.4 to 0.6 mm L3 = 0.4 to 0.6 mm In the case of an inductance element having a size such that
The winding density is preferably 15 turns / mm to 30 turns / mm. With such a configuration, an element having a high inductance of 55 nH or more can be realized, and furthermore, disconnection and the like can be prevented.

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

First, the base 11 is manufactured by pressing or extruding 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, a 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 in particular, a nickel layer or a solder layer may be laminated 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.

Although the present embodiment has been described with respect to an inductance element, 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 33. 3
Reference numeral 5 denotes a receiving unit that converts a received signal received by the antenna 33 into an audio signal. The audio signal created by the receiving unit 35 is converted into audio by the speaker 30. A control unit 36 controls the transmission unit 34, the reception unit 35, 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, a case of transmitting 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 filter circuit and a matching circuit in the IF section of the wireless terminal device,
It is used as a filter for removing noise. As described above, the size of the device can be reduced by mounting an inductor having a high inductance, a small size, and little deterioration of the Q value. Also, by using an inductance element having a very high inductance as described above,
Since the filter can be used as a filter for removing noise and the filter can be made very small, the size of the device itself can be reduced.

[0072]

According to the present invention, a conductive film provided on a base made of a material containing alumina as a main component and having a surface roughness of 1 μm or less, and a spiral groove provided in the conductive film are provided. L1 = 0.5-2.1 mm L2 = 0.2-1.5 mm L3 = 0.2-1.5 mm when length L1, width L2, height L3 And an inductance element having an inductance of 55 nH or more, wherein the thickness of the conductive film is 5 to 20 μm and the winding density of the winding portion of the conductive film is 15 turns / mm to 50 turns / mm. By setting the surface roughness of the base to 0.15 μm to 0.5 μm, it is possible to have a small size, cope with a high frequency and to have a high inductance, and to prevent troubles such as disconnection. , It has an excellent configuration for mass production, Can be extremely reduced leakage occurrence rate, further or DC resistance is increased, it is possible to prevent the Q value is deteriorated, further
Can improve the adhesion strength between the conductive film and the base.
Can Ru.

Also, voice signal conversion means for converting voice into voice signals, operation means for inputting telephone numbers and the like, display means for displaying incoming calls and telephone numbers, and the like, and demodulation of voice signals into transmission signals A wireless terminal device comprising: 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 control unit for controlling each unit. By using the inductance element according to any one of claims 1 to 5 as the element, it is possible to have a high inductance, to be small in size, to reduce the deterioration of the Q value, and to perform noise reduction with a very small element. Therefore, the size and weight of the device can be reduced.

[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 graph showing the relationship between the thickness of a conductive film used for an inductance element and the leak rate according to an 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 partially enlarged view showing an inductance element according to an embodiment of the present invention.

FIG. 16 is a graph showing the relationship between C and DC resistance of the inductance element according to the embodiment of the present invention.

FIG. 17 is a graph showing a relationship between C and Q values of the inductance element according to the embodiment of the present invention.

FIG. 18 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

Continuing from the front page (72) Inventor Yoshihiro Inoue 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 56) References JP-A-6-204042 (JP, A) JP-A-5-299250 (JP, A) JP-A-9-219318 (JP, A) JP-A-6-314622 (JP, A) JP-A-8-88123 (JP, A) JP-A-5-267085 (JP, A) JP-A-1-238003 (JP, A) Japanese Utility Model Application Showa 60-114426 (JP, U)

Claims (5)

(57) [Claims] 1. A base made of a material mainly composed of alumina, a conductive film provided on the base and having a surface roughness of 1 μm or less, and a spiral groove provided in the conductive film. L1 = 0.5-2.1 mm L2 = 0.2-1.5 mm L3 = 0.2-1.5 mm when length L1, width L2, and height L3 are provided. And an inductance element having an inductance of 55 nH or more, wherein the thickness of the conductive film is 5 to 20 μm and the winding density of the winding portion of the conductive film is 15 turns / mm to 50 turns / mm. The base element has a surface roughness of 0.15 μm to 0.5 μm . 2. The inductance element according to claim 1, wherein a protective material is provided to cover the groove, and a difference between the irregularities of the protective material is set to 70 μm or less. A step portion is provided in a central portion of 3. A device, the depth of the stepped portion and 5 to 50 [mu] m, according to claim 2, characterized in that provided a groove and the protective material in the step portion Inductance element. 4. When the width of a conductive film sandwiched between grooves is P5 and the width of the groove itself is P6, the value of P5 ÷ P6 is 0.85.
Claim, characterized in that it is to 1.1 1-3 or 1
The inductance element described. 5. 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 and a telephone number, etc. A wireless terminal device comprising: 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 control unit for controlling each unit. as the device, the radio terminal device characterized by using an inductance element as claimed in any one claims 1-4.