JPH08186024A - Multilayer inductor - Google Patents

Abstract

PURPOSE: To provide a multilayer inductor, which can be reduced the loss of a conductor to a minimum without generating a peeling of insulating layers and without increasing the plane area of a substrate. CONSTITUTION: A multilayer inductor is formed into a constitution, wherein a coil formed by connecting a plurality of coil patterns 2A and 2B to each other into a spiral form is arranged in a multilayer board 1 formed by stacking a plurality of insulating layers 1a to 1e. The coil pattern 2A is constituted by parallel-connecting conductor patterns 2b and 2c, which are respectively formed between the layers 1a and 1b adjacent to each other and between the layers 1b and 1c adjacent to each other and are substantially formed into the same form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor capable of reducing the attenuation of current generated by the conductor resistance of a coil pattern (hereinafter referred to as conductor loss).

[0002]

2. Description of the Related Art Generally, multilayer inductors are widely used in electronic equipment and devices by using high frequency, and have a small mounting area,
High performance and low price are required.

The laminated inductor has a structure in which a coil pattern having a predetermined number of turns is arranged between the respective layers of an insulating layer (including a dielectric material and a magnetic material) forming a laminated substrate, and one end of the coil pattern is adjacent to an insulating layer. The coil pattern arranged between the layers is connected to the other end through a via-hole conductor that penetrates the insulating layer in the thickness direction. As a result, a coil composed of a plurality of coil patterns connected by via-hole conductors is formed inside the laminated substrate, both ends of the coil are extended to the outside of the laminated substrate, and terminal electrodes are provided at the extended portions of both ends. Had been formed.

In the above-mentioned laminated inductor, a through hole which becomes a via hole conductor is formed on a green sheet which becomes an insulating layer, and thereafter a conductive film which becomes a coil pattern is formed by printing a conductive paste on the green sheet. To do.
By this printing, the conductor paste is filled in the through holes, and a conductor to be a via hole conductor is formed.

A plurality of green sheets having such a conductor film formed thereon and a green sheet to be a surface layer are heat-pressed and fired to form terminal electrodes.

[0006]

In the above laminated inductor, the conductor film forming the coil pattern is Au, A
Although it is formed of a conductive paste containing g, platinum, copper, etc. as a main component, the conductor resistance of the coil pattern has been reduced. However, if the conductor resistance related to the basic characteristics of the coil is further reduced, the conductive paste is Increase the thickness of the conductor film that becomes the coil pattern formed by
It is necessary to widen the width of the coil pattern.

For example, when the thickness of the conductor film is increased, the difference in thickness between the portion where the conductor film is present and the portion where the conductor film is not present on the green sheet is large, and during the thermocompression bonding in the laminating step or the firing step. There is a high possibility that peeling between the insulating layers will occur during the baking treatment of.

Further, when the width of the coil pattern is widened, the area occupied by the coil pattern on the green sheet is increased and the planar area of the laminated board is increased, so that the mounting area on the printed wiring board is increased. Will increase.

Therefore, the thickness, width, etc. of the coil pattern or the conductor film forming the coil pattern are restricted, and as a result, there is a limit to the reduction of the conductor resistance.

The present invention has been made in view of the above problems, and an object thereof is to propose a laminated inductor capable of effectively reducing the conductor resistance of a coil formed by connecting coil patterns by via-hole conductors. To do.

[0011]

According to the present invention, a coil formed by spirally connecting a plurality of coil patterns via via-hole conductors is arranged in a laminated substrate formed by laminating a plurality of insulating layers. In the laminated inductor described above, the coil pattern is a laminated inductor formed by connecting a plurality of conductor pattern layers of substantially the same shape formed between adjacent insulating layers with a plurality of via hole conductors.

[0012]

As described above, the coil pattern forming the coil in the laminated substrate formed by laminating a plurality of insulating layers has a plurality of via holes formed by conductor pattern layers of substantially the same shape formed between adjacent insulating layers. It is configured by being connected by a conductor.

Therefore, the current flowing in the predetermined coil pattern is shunted to the plurality of conductor pattern layers connected in parallel with each other, so that the current capacity per pattern can be made sufficiently large and the conductor loss can be reduced. Can be greatly reduced.

As a result, although the number of laminated boards is increased, the characteristics can be greatly improved without changing the mounting area on the printed wiring board.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The laminated inductor of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an external perspective view of the laminated inductor of the present invention, and FIG. 2 is an exploded perspective view in which each insulating layer is disassembled.

In FIG. 1, the laminated inductor is an insulating layer made of a magnetic material, a dielectric ceramic material or the like (in the present invention, a layer made of a magnetic material, a dielectric ceramic material or the like is called an "insulating layer"). ) 1a to 1e are laminated, and the laminated substrate 1 and terminal electrodes 4 and 5 formed at a pair of opposing end portions of the laminated substrate 1.

The laminated substrate 1 is composed of an insulating layer containing a magnetic material, a dielectric ceramic material and, if necessary, a glass component, and is formed by laminating, for example, five insulating layers 1a to 1e.

Conductor pattern layers 2b to 2e made of a low resistance material such as Au, Ag, Cu and Pt are formed between the insulating layers of the insulating layers 1a to 1e of the laminated substrate 1.

Here, the conductor pattern layers 2b and 2c have substantially the same pattern and are connected to each other in parallel by the first via-hole conductors (hereinafter referred to as parallel via-hole conductors) 21 and 22. Thereby, the insulating layer 1a
And 1b, and between the insulating layers 1b and 1c, that is, between the adjacent layers, the conductor pattern layers 2b and 2c are connected in parallel to form a first coil pattern 2A.

The conductor pattern layers 2d and 2e have substantially the same pattern, and the parallel via-hole conductors 23 and 24 are provided.
Are connected in parallel with each other. This allows
The conductor pattern layers 2d and 2e between the insulating layers 1c and 1d and between the insulating layers 1d and 1e, that is, the adjacent layers are connected in parallel to form a second coil pattern 2B.

The first coil pattern 2A and the second coil pattern 2B thus configured have the insulating layer 1c.
One end of the coil pattern 2A and the other end of the second coil pattern 2B are connected by the second via-hole conductor (hereinafter, referred to as connection via-hole conductor) 3 formed in
As a result, the coil patterns 2A and 2B are spirally connected.

The other end of the first coil pattern 2A is extended to the outside of the laminated substrate 1 by, for example, a via hole conductor 31, and one end of the second coil pattern 2B is formed by, for example, a via hole conductor 32. 1 is extended to the outside.

Terminal electrodes 4 and 5 are formed at opposite ends of the laminated substrate 1 including the extended portions of the via-hole conductors 31 and 32, and a predetermined inductance component is derived between the terminal electrodes 4 and 5. You can

The parallel via-hole conductors 21, 22, 2
3, 24, connection via-hole conductor 3, via-hole conductor 3
Reference numerals 1 and 32 are each made of a conductor made of low resistance material such as Au, Ag, Cu, Pt, and the terminal electrodes 4, 5 are made of a conductor whose main component is a low resistance material such as Ag or Cu. If necessary, Ni plating, solder plating or the like is adhered and formed on the surface.

With the above configuration, for example, the terminal electrode 3
The current flowing between 1 and 32 is the first coil pattern 2
A, when flowing through the second coil pattern 2B, it is divided into two, and the coil patterns 2A, 2B
It is possible to sufficiently reduce the conductor loss generated in the above.

For this reason, since it is not necessary to increase the thickness of the conductor pattern layers 2b to 2e forming the coil pattern, the peeling phenomenon between the insulating layers 1a to 1e does not occur in the manufacturing process, and the coil patterns 2A, Since the width of 2B does not have to be very wide, the planar area of the laminated substrate 1 does not become large, so that the mounting area on the printed wiring board can be kept sufficiently small, and the coil pattern 2A,
It is possible to effectively reduce the conductor loss due to 2B and improve the characteristics.

Such a laminated inductor is formed by the following manufacturing process.

First, a slip material obtained by mixing a predetermined insulating material and an organic vehicle is tape-formed by a doctor blade method and further cut into a predetermined shape to form a green sheet.

Next, the green sheet to be the insulating layer 1a is connected to the through hole to be the via hole conductor 31, the green sheet to be the insulating layer 1b is connected to the through holes to be the parallel via hole conductors 21 and 22, and the green sheet to be the insulating layer 1c is connected. A through hole to be the via hole conductor 3, a through hole to be the parallel via hole conductors 23 and 24 in the green sheet to be the insulating layer 1d, and a through hole to be the via hole conductor 32 in the green sheet to be the insulating layer 1e are formed by punching. In addition, it is desirable that the through hole is made large enough to prevent the conductor from being omitted after the conductive paste is filled.

Next, a conductor film to be the conductor pattern layers 2b and 2c is formed on the green sheet to be the insulating layers 1b and 1c.
For example, it is formed by printing and drying a conductive paste containing Ag as a main component. At this time, the through holes formed in each green sheet are filled with the conductive paste during printing.

Next, a conductor film to be the conductor pattern layers 2d and 2e is formed on the green sheets to be the insulating layers 1d and 1e.
For example, it is formed by printing and drying a conductive paste containing Ag as a main component.

Here, what is important is that the conductor film patterns of the conductor pattern layers 2b and 2c which become the first coil pattern 2A and the conductor pattern layers 2d and 2e which become the second coil pattern 2B are substantially the same. Therefore, it suffices to prepare a screen plate for each type, and the work efficiency is improved.

Next, the green sheets to be the insulating layers 1a to 1e are thermocompression-bonded in consideration of the order of lamination to be laminated and integrated.

The unfired laminate thus obtained is cut into a predetermined size and subjected to firing treatment.

A conductive paste is dipped and applied to the end portion of the fired laminated substrate 1, baked and then plated if necessary to form the terminal electrodes 4 and 5.

Various changes can be made to the method of forming the terminal electrodes 4 and 5.

In the above-mentioned embodiment, the laminated inductor in which the coil having the simplest structure is formed has been described. However, it is possible to form two coils in the laminated substrate 1 and use it as a transformer component.

Also, one coil pattern, for example, the first
The two conductor pattern layers 2b and 2c constituting the coil pattern 2A are connected at one end and the other end, but a plurality of parallel via-hole conductors may be formed between the two ends. Further, the first coil pattern 2A is formed between two insulating layers that are adjacent to each other, but conductor pattern layers having substantially the same shape may be formed between three or more continuous insulating layers that are adjacent to each other. Absent.

Further, the coil is the first coil pattern 2
Connects A and the second coil pattern 2B Via-hole conductor 3
Therefore, the coil patterns are connected in a spiral shape, but the number of coil patterns may be three or more.

[0041]

As described above, according to the present invention, since the coil pattern forming the coil is formed by connecting the plurality of conductor pattern layers arranged in the adjacent insulating layers in parallel, the coil pattern is formed. It is possible to shunt the current flowing therethrough and substantially reduce the conductor resistance of the coil pattern to 1 / n, so that the deterioration of the characteristics can be effectively suppressed.

Moreover, peeling between the insulating layers and planar spreading of the laminated substrate can be effectively suppressed. Since the conductor pattern layers forming the coil pattern have substantially the same pattern, the conductor film serving as the conductor pattern layer is formed. Can be formed in common, and the manufacturing process is not complicated.

[Brief description of drawings]

FIG. 1 is an external perspective view of a laminated inductor of the present invention.

FIG. 2 is an exploded perspective view of the laminated inductor of the present invention.

[Explanation of symbols]

 1 ... Multilayer substrate 1a to 1e ... Insulating layer 2A ... First coil pattern 2b, 2c ... Conductor pattern layer 21, 22 ... Parallel via-hole conductor 2B ... 2 coil patterns 2d, 2e ... Conductor pattern layers 23, 24 ... Parallel via hole conductors 3 ... Connection via hole conductors 31, 32 ... Via hole conductors 4, 5 ... Terminal electrode

Claims (1)

[Claims] 1. A laminated inductor in which a coil formed by spirally connecting a plurality of coil patterns through a via-hole conductor is arranged in a laminated substrate formed by laminating a plurality of insulating layers, wherein the coil pattern is A multilayer inductor characterized by being formed by connecting a plurality of conductor pattern layers of substantially the same shape formed between adjacent insulating layers with a plurality of via-hole conductors.