JP3035479B2 - Multilayer inductance element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer inductance element which is applied to various electronic devices and functions as an LC filter or a resonator.

[0002]

2. Description of the Related Art In recent years, with the advancement of electronic equipment technology, the frequency band of signals handled in electronic equipment has been extended to the high frequency side, and the band extends from several hundred MHz to several GHz. A resonator used in a circuit for separating or synthesizing signals in such a high frequency band is required to have a high gain (Q) in a target frequency band, and a magnetic layer containing a magnetic powder is required. Laminated inductance elements have been used in which a paste for conductive layer and a paste for conductive layer containing conductive powder are alternately printed and co-fired.

[0003]

Generally, Ni, Zn, C are used as soft magnetic core materials for inductance elements.
Spinel-type ferrite sintered bodies composed of u and Fe have been used. However, when these composition-based inductance elements are used in a high-frequency range (100 MHz), the gain (Q) is remarkably reduced, and the inductance is also sharply reduced. There was a point.

It is an object of the present invention to provide a multilayer inductance element having excellent inductance and Q characteristics in a high frequency band and applicable to a wide frequency band.

[0005]

As a result of various studies, the present inventors have found that the basic composition of the spinel-type soft magnetic ferrite powder is aFe ₂ O ₃ , bNiO, cCuO (mol%).
Consisting of 10 additives, each having a main component of 42 <a <50, 40
<B <48, 4 <c <8, a + b + c = 100 mol%
And a composition in which Bi ₂ O ₃ , MnO, and CoO are each added in an amount of 0 to 0.5 wt% (each element does not include 0 wt%), and magnetic layers and conductor layers are alternately laminated. Then, they have found that it is possible to obtain a multilayer inductance element that can be applied in a wide frequency band by forming a conductor coil inside.

That is, according to the present invention, a soft magnetic ferrite powder and a conductor powder are each formed into a paste using a synthetic resin binder, and these are laminated by a printing method to form a coil-shaped conductor, which is simultaneously fired. In the multilayer inductance element, the soft magnetic ferrite powder contains 42 <a <50, 40 <b <48, and 4 <c as main components, respectively.
<8, aFe ₂ O ₃ and bNi satisfying a + b + c = 100
O, cCuO (mol%), and 0-
This is a multilayer inductance element comprising Bi ₂ O ₃ , MnO, and CoO in an amount of 0.5 wt% (each element does not include 0 wt%).

Here, the evaluation items of the electrical characteristics employed in the present invention as criteria for determining the inductance element will be described.

The characteristics are evaluated by the frequency characteristics of the inductance (L), the frequency characteristics of the gain (Q), and the temperature characteristics of the element.
LT is the resonance frequency.

△ LT indicates the temperature change rate (% / ° C.) of L from 0 to 80 ° C. based on the value of L at 20 ° C. and 100 kHz, and is obtained by the following equation. ΔLT = [(L80−LO) / (L20 × 80)] × 100 (% / ° C.) The resonance frequency is the value of the frequency when the inductance of the element becomes zero.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples.

(Example 1) The chemical composition ratio was aFe ₂ O ₃ , bNiO, cCuO (m
ol%) + Bi ₂ O ₃ : 0.2 wt% · CoO: 0.2
wt%, MnO: 0.2 wt%, a + b + c =
100, a = 41, 42, 43, 44, 45, 46, 4
Each raw material was prepared so that 7, 48, 49, 50, 51, and c = 6, and was wet-mixed with a ball mill for 20 hours. The particle sizes of the raw material powders used here are all 0.5 μm or less.

Next, the mixed powder of these raw materials is
After calcining at 0 ° C. for 2 hours, the mixture was wet-ground with a ball mill for 3 hours to obtain a spinel-type soft magnetic ferrite powder. The average particle size of the powder is about 1 μm.

The powder, the binder, and the solvent were blended in the ratio shown in Table 1, and the blend was kneaded with a three-roll mill to produce a paste for a magnetic layer.

[0014]

The powder for the conductor layer has an average particle size of 05 μm.
Of Ag powder was prepared. This powder was mixed with a binder and a solvent at the ratios shown in Table 2, and the mixture was kneaded with a three-roll mill to prepare a conductor layer paste.

[0016]

In this embodiment, the pastes were prepared with the compounding ratios shown in Tables 1 and 2, but any other compounding ratios may be used as long as a printable paste can be obtained. further,
Although a three-roll mill was used for kneading the mixture, a homogenizer or a sand mill may be used instead.

Next, the magnetic layer paste thus produced was laminated to a predetermined thickness (0.5 mm) by a printing method. Printing and lamination were performed thereon so as to form a laminate winding of 5.5 turns of the conductor using the conductor layer paste and the magnetic layer paste. At this time, the thickness of one layer was about 30 μm for the magnetic layer and about 15 μm for the conductor layer.

On top of this, a magnetic layer paste was laminated to a predetermined thickness (0.5 mm) by a printing method. The overall stack thickness is about 1.3 mm.

In this embodiment, the laminated winding of the conductor is 5.5
Although the winding is used, other windings may be used, and the winding may be adjusted so as to obtain necessary characteristics.

The above-prepared laminate is reduced to a predetermined size by 3
mm x 1.5 mm. After removing the binder from the laminated and cut laminates, simultaneous firing was performed at 850 ° C. In the present embodiment, the sintering was performed at 850 ° C., but any temperature may be used as long as it is a temperature at which sintering of the laminate is completed and the internal electrodes are not disconnected.

Further, the size of one laminated element is 3 mm ×
Although 1.5 mm was used, other sizes may be used. In such a case, the size of the laminated conductor winding may be adjusted.

In the fired laminated inductance element,
A conductor layer paste containing Ag as a main component is applied to a surface of the conductor laminated winding where the leads are exposed, and is applied at about 300 ° C.
Was performed to form external electrodes.

FIG. 1 shows the configuration of the multilayer inductor. FIG. 1A is a plan view from the lamination surface, and FIG. 1B is a sectional view.

As shown in FIG. 1, a conductor 2 is laminated and wound in a magnetic body 1. Reference numeral 3 denotes an external electrode formed after firing.

In this embodiment, a conductor layer paste containing Ag as a main component is used as the external electrode. However, a conductor layer paste containing carbon, Cu, Ni, or the like as a main component may be used. .

The maximum value (hereinafter referred to as Q _MAX ) of the gain (Q) of the laminated inductance element manufactured as described above is 1
The inductance value at 00 kHz (hereinafter, L100 kHz
z), the temperature characteristic of the inductance and the resonance frequency are determined by a YHP impedance analyzer HP4191A.
Was evaluated using Table 3 shows the results.

[0028]

[Table 3]

According to Table 3, when a is smaller than 42, Q _MAX
Significantly decreases, and when a exceeds 50, the resonance frequency, △
LT significantly decreases. Therefore, a = 42 to 50 is a useful composition range.

Example 2 The chemical composition ratio was aFe ₂ O ₃ , bNiO, cCuO (m
ol%) + Bi ₂ O ₃ : 0.2 wt% · CoO: 0.2
wt% · MnO: 0.2 wt%, where a + b
+ C = 100, b = 39, 40, 41, 42, 43, 4
Each raw material was prepared so that 4, 45, 46, 47, 48, 49, and c = 4, and a multilayer inductance element was manufactured in the same manner as in Example 1. The produced device was evaluated in the same manner as in Example 1. Table 4 shows the results.

[0031]

[Table 4]

Table 4 shows that ΔLT significantly increases when b exceeds the range of 40 to 48. Therefore, the range of b = 40 to 48 is a useful composition range.

Example 3 The chemical composition ratio was aFe ₂ O ₃ , bNi _O , cCuO (m
ol%) + Bi ₂ O ₃ : 0.2 wt% · CoO: 0.2
wt% · MnO: 0.2 wt%, where a + b
+ C = 100, b = 46, c = 3, 4, 5, 6, 7,
Each raw material was prepared so as to obtain 8, 9 and a multilayer inductance element was produced in the same manner as in Example 1. The produced device was evaluated in the same manner as in Example 1. Table 5 shows the results.

[0034]

As shown in Table 5, when c exceeds the range of 4 to 8, △
This indicates that LT is significantly increased. Furthermore, c
At> 8, the resonance frequency decreases. Therefore, c = 4-8
Is a useful composition range.

Example 4 The chemical composition ratio was aFe ₂ O ₃ , bNiO, cCuO (m
ol%) + dBi ₂ O ₃ .CoO: 0.2 wt% · Mn
O: expressed by 0.2 wt%, provided that a + b + c = 10
0, a = 48, b = 46, c = 6, d = 0, 0.01,
0.05, 0.1, 0.2, 0.3, 0.4, 0.5,
Each raw material was prepared so as to be 0.6 wt%, and a multilayer inductance element was produced in the same manner as in Example 1. The produced device was evaluated in the same manner as in Example 1. Table 6 shows the results.
Shown in

[0037]

[Table 6]

From Table 6, when d = 0, Q _MAX and ΔLT are low. When d> 0, Q _MAX is improved.
ΔLT also improves, but if d exceeds 0.5, the resonance frequency decreases. Therefore, d = 0 to 0.5 (0 is not included)
Is a useful composition range.

Example 5 The chemical composition ratio was aFe ₂ O ₃ , bNiO, cCuO (m
ol%) + Bi ₂ O ₃ : 0.2 wt% · eCoO · Mn
O: expressed by 0.2 wt%, provided that a + b + c = 10
0, a = 48, b = 46, c = 6, e = 0, 0.01,
0.05, 0.1, 0.2, 0.3, 04, 0.5,
Each raw material was prepared so as to be 0.6 wt%, and a multilayer inductance element was produced in the same manner as in Example 1. The produced device was evaluated in the same manner as in Example 1. Table 7 shows the results.
Shown in

[0040]

[Table 7]

As shown in Table 7, when e = 0, Q _MAX is low. When e> O, Q _MAX is improved, and the resonance frequency is further improved up to the high frequency band.
LT significantly decreases. Therefore, the range of e = 0 to 0.5 (excluding 0) is a useful composition range.

Example 6 The chemical composition ratio was aFe ₂ O ₃ , bNiO, cCuO (m
ol%) + Bi ₂ O ₃ : 02 wt% · CoO: 0.2 w
t% · fMnO, where a + b + c = 100,
a = 48, b = 46, c = 6, f = 0, 0.01, 0.
05, 01, 0.2, 0.3, 0.4, 0.5, 0.6
Each raw material was prepared so as to be wt%, and a multilayer inductance element was produced in the same manner as in Example 1. The produced device was evaluated in the same manner as in Example 1. Table 8 shows the results.

[0043]

[Table 8]

[0044] From Table 8, it improves the _{Q MAX} at f> 0, the amount is exceeds f = 0.5, _{conversely, Q MAX} is decreased. Therefore, the range of f = 0 to 0.5 (excluding 0) is a useful composition range.

Example 7 The chemical composition ratio of the main component was 48Fe ₂ O ₃ -46Ni-6.
CuO, and Bi ₂ O ₃ : 0.1 wt.
% · CoO: 0.3 wt% · MnO: 0.2 wt% Each of the powders to which powder was added was used to fabricate a multilayer inductance element in the same manner as in Example 1.

FIG. 2 shows the relationship between the frequency and L and Q of the manufactured laminated inductance element, and Table 9 shows the resonance frequency. 2 and Table 9 show, as a comparative example, the relationship between the frequency, the L and Q, and the resonance frequency of the laminated inductance element manufactured using the same spinel-type Ni-Cu-Zn ferrite as the magnetic material as the example. Show.

[0047]

As can be seen from FIG. 2, the use of the magnetic layer paste having the composition range shown in the present embodiment slightly lowers the effective magnetic permeability and hence the inductance L.
Up to 00 MHz, L shows a flat characteristic.
Frequency band shows a peak has also reached more than 100 MHz, furthermore, Q _MAX even higher than conventional laminated inductance element, therefore, was found to be laminated inductance element that can be applied in a wide frequency band. Table 9
As can be seen from the figure, it was found that the resonance frequency was also in a high frequency range.

[0049]

As described above, according to the present invention,
A multilayer inductance element having excellent inductance and Q characteristics in a high frequency band and applicable in a wide frequency band can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a laminated inductor of the present embodiment. FIG. 1A is a plan view. FIG. 1B is a sectional view.

FIG. 2 is a diagram showing the relationship between the frequency, L, and Q of a multilayer inductance element of Example 7 and a multilayer inductance element of a comparative example. FIG. 2A is a diagram illustrating a relationship between frequency and Q. FIG. 2B is a diagram illustrating a relationship between frequency and L.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic body 2 Conductor 3 External electrode A Example 7 B Comparative example

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 17/00 H01F 1/34

Claims (1)

(57) [Claims] 1. A paste of a soft magnetic ferrite powder and a conductor powder using a synthetic resin binder, respectively.
These are laminated by a printing method to form a coil-shaped conductor, and in the laminated inductance element co-fired, the soft magnetic ferrite powder contains 42 <a <50, 40 <b <48, 4 <c <8, a + b
AFe ₂ O ₃ , bNiO, cCuO where + c = 100
(Mol%) and 0 to 0.5 wt% as sub-components, respectively.
Bi ₂ O ₃ , which does not contain 0 wt% for each element,
A multilayer inductance element comprising MnO and CoO.