JPH07176430A - Laminated inductor and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a highly reliable laminated inductor in which the adhesive strength between a terminal electrode and the lead-out part of an inner coil conductor is excellent. CONSTITUTION:An inner conductor 11 is wound inside a laminated body of an insulator by printing a conductor material consisting mainly of a silver, and a lead-out conductor 12 of its end part is formed by printing a conductor consisting mainly of a silver and paradium on a conductor consisting mainly of a silver. A terminal electrode 13 is formed on the exposed end face with the conductor 12, by baking, etc., thereby obtaining a lmainated inductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor and a method for manufacturing the same, and more particularly to a material for an inner conductor.

[0002]

2. Description of the Related Art In order to meet demands for miniaturization and thinning of electronic components, various inductors without windings have been considered and put into practical use in the field of inductors. It is formed by forming a conductor pattern on a magnetic sheet such as ferrite and laminating it, or by alternately printing and laminating a magnetic paste and a conductor paste. An air-core structure using a non-magnetic material is also used.

The conductor pattern inside the laminated inductor is formed of a conductor material containing silver or silver / palladium as a main component. It is desirable to use silver in terms of conductor resistance, but when silver is used, a phenomenon occurs in which it disappears from the end face during firing, so the firing temperature has an upper limit (900 ° C). . After firing, an external electrode made of silver or the like is connected to the internal electrode as a terminal electrode, and a plating layer or the like is formed on the surface thereof as needed.

[0004]

In the laminated inductor using silver as the internal conductor as described above, the adhesive strength between the lead-out portion at the end of the conductor pattern and the terminal electrode cannot be sufficiently obtained, and the plating is not performed. However, there is a problem in that the plating solution enters inside when applying the heat treatment and causes mechanical destruction (commonly called popping) due to heating during soldering.

The present invention solves such a problem, improves the adhesion strength between the lead-out portion of the internal conductor and the terminal electrode, and increases the heat resistance of the product to obtain a highly reliable laminated inductor. .

[0006]

The present invention solves the above problems by adopting an electrode material containing silver / palladium as a main component instead of silver as the electrode material of the extraction portion.

That is, in a laminated inductor in which a conductor pattern that overlaps and circulates in the lamination direction is provided inside a laminated body of insulators, and both ends of the conductor pattern are drawn out to the side surface of the laminated body and connected to terminal electrodes This is characterized in that the internal conductor pattern is formed of a conductive material containing silver as a main component, and the lead-out portion connected to the external terminal is formed of a conductive material containing silver / palladium as a main component.

In addition, an insulating layer and a conductor pattern are alternately printed and laminated to form a conductor pattern which overlaps and circulates in the laminating direction, and an end portion of the conductor pattern is in contact with a side surface of the laminate to form a drawer. In the method for manufacturing a laminated inductor, the terminal portion of which is connected to an external part and the terminal electrode is formed after firing the laminated body. It is characterized by being formed of a conductive material containing palladium as a main component.

It is also possible to use a sheet laminating method instead of the printing laminating method, or to perform firing and baking of terminal electrodes at the same time after individually dividing a laminate from an unfired one in which a large number of laminated inductors are formed.

[0010]

In the silver / palladium conductor material of the lead portion formed by connecting to the terminal electrode, palladium has a high melting point and does not disappear. By diffusing this palladium into the material of the terminal electrode, the adhesion strength between the lead-out portion of the internal conductor containing palladium and the terminal electrode is improved. In addition, the degree of adhesion between the drawn-out portion and the body of the insulating material is improved, the plating solution is prevented from entering the inside of the element, and mechanical destruction (popping) due to heating during soldering can be prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the present invention. A magnetic or non-magnetic insulating material (10) is laminated, and an internal conductor (11) is formed between the layers. The inner conductor 11 forms a conductor pattern, that is, a coil pattern, which is overlapped in the stacking direction and circulates while the ends are connected between layers. The laminated body of the insulating material 10 can be formed by the sheet laminating method or the print laminating method. In the case of the sheet method, it is common to connect the conductors by through holes, and in the case of the printing method, the ends of the conductors are exposed and the conductors of the next approximately half turn are printed by connecting to the exposed parts. .

Both ends of the inner conductor 11 are drawn out to the end faces of the laminated body made of the insulating material 10. Usually, a wide lead conductor 12 is formed in contact with the facing end faces. In the present invention,
The inner conductor 11 is formed by printing a conductor paste containing silver as a main component, and the lead conductor 12 is formed by printing a conductor paste containing silver / palladium as a main component. In the actual formation, the conductor paste containing silver / palladium as a main component is printed on the end portion of the internal conductor containing silver as a main component.

As described above, the inner conductor 11 and the lead conductor 12
The laminated body in which a large number of are formed is divided into chips and fired.
After firing, the terminal electrode material is applied to the drawn end surface of the lead conductor and baked to form the terminal electrode 13. The formation of this terminal electrode 13 can be performed simultaneously with the firing of the chip. The terminal electrode 13 is generally made of nickel or solder plated on a silver or copper base.

FIG. 2 is a plan view showing a method for forming a lead conductor according to the present invention. An example of the lead conductor formed last is shown, but the same applies to the case where it is formed first. A conductor pattern 21b extending linearly is formed on the side surface of the laminated body 20 by connecting to the conductor pattern 21a of the last approximately half turn. The conductor pattern 21b is formed wide near the end face so that the first lead conductor layer 22a is simultaneously formed. This conductor pattern 21
The portions a, 21b and 22a are formed by printing a conductive material containing silver as a main component.

The conductor pattern 22b overlaps the conductor pattern 22a containing silver as a main component and is exposed on the side surface of the laminate 20.
Is formed. The conductor pattern 22b is formed by printing a conductor material containing silver / palladium as a main component. Although not shown, a predetermined number of insulating layers are formed on this and baked.

[0017]

According to the present invention, the lead conductor containing silver / palladium as a main component is diffused in the terminal electrode material and alloyed to improve the adhesion strength between the internal electrode and the terminal electrode.

Further, the degree of adhesion between the element body and the drawn-out portion is improved, the invasion of the plating solution can be prevented, and the destruction due to the heat at the time of soldering can be prevented, so that the mechanical strength is secured and the reliability is improved. In addition, it becomes easy to maintain the electrical characteristics.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment (structure) of the present invention.

FIG. 2 is a plan view showing an embodiment (method) of the present invention.

[Explanation of symbols]

 11, 21: Inner conductor 12, 22: Lead-out conductor 13: Terminal electrode

Claims (5)

[Claims] 1. A laminated inductor in which a conductor pattern that overlaps and circulates in the laminating direction is provided inside an insulator laminate, and both ends of the conductor pattern are drawn out to the side surface of the laminate to connect to a terminal electrode. A multilayer inductor, wherein the inner conductor pattern is formed of a conductor material containing silver as a main component, and the lead-out portion connected to the external terminal is formed of a conductor material containing silver / palladium as a main component. 2. A drawer formed by alternately printing and laminating an insulating layer and a conductor pattern to form a conductor pattern which is superposed in the laminating direction and circulates, and an end portion of the conductor pattern is in contact with a side surface of the laminate. In a method for manufacturing a laminated inductor, in which a terminal electrode is formed after firing the laminated body after firing the laminated body, the circulating conductor pattern is formed of a conductor material containing silver as a main component,
A method of manufacturing a laminated inductor, characterized in that a lead-out portion connected to an external terminal is formed of a conductive material containing silver / palladium as a main component. 3. A drawer formed by alternately printing and laminating an insulating layer and a conductor pattern to form a conductor pattern that overlaps and circulates in the laminating direction, the end of the conductor pattern being in contact with the side surface of the laminate. In the method for manufacturing a laminated inductor in which a terminal electrode is formed at the same time when the laminated body is connected to an external part and the laminated body is fired, a circulating conductor pattern is formed of a conductive material containing silver as a main component, and a lead portion connected to an external terminal is formed of silver. / A method for manufacturing a laminated inductor, characterized in that the laminated inductor is formed of a conductive material containing palladium as a main component. 4. An insulating sheet is laminated and conductor patterns formed on the surface of the insulating sheet are connected to form a conductor pattern which is superposed in the laminating direction and circulates, and an end portion of the conductor pattern is in contact with a side surface of the laminate. In the method for manufacturing a laminated inductor, in which the laminated body is connected to the drawn-out portion and the laminated body is fired to form the terminal electrode, the circling conductor pattern is formed of a conductor material containing silver as a main component and is connected to an external terminal. A method of manufacturing a laminated inductor, characterized in that the lead-out portion is formed of a conductive material containing silver / palladium as a main component. 5. An insulating sheet is laminated and conductor patterns formed on the surface thereof are connected to each other to form a conductor pattern which overlaps and circulates in the laminating direction, and an end portion of the conductor pattern is in contact with a side surface of the laminate. In the method for manufacturing a laminated inductor in which a terminal electrode is formed at the same time when the laminated body is connected to the lead portion formed by The method of manufacturing a laminated inductor, wherein the lead-out portion is formed of a conductor material containing silver / palladium as a main component.