JP2003037014A - Laminated inductor mounted structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated inductor mounted structure which can obtain stable characteristics even when a component carrying direction is changed by the form and the position of a terminal electrode. SOLUTION: A pair of terminal electrodes 3 are provided at an end part in the longitudinal direction of a chip 1 which constitutes the laminated inductor, and as a round center line Y of a coil 2 embedded in the chip 1 is in parallel with a direction (the longitudinal direction of the chip) of connecting with the terminal electrode 3, even if the carrying direction is changed, the direction of the round central line Y of the coil 2 with respect to a substrate plane is not changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor mounting structure including a laminated inductor in which a coil is embedded in a chip having a laminated structure and a substrate on which the laminated inductor is mounted.

[0002]

2. Description of the Related Art FIG. 6 is a schematic sectional view of a conventional laminated inductor.

In the figure, 11 is a rectangular parallelepiped chip made of a magnetic material, 12 is a spiral coil embedded in the chip 11, 13 is a pair of terminal electrodes provided at the ends of the chip 11 in the longitudinal direction. Is. The winding center line Y of the coil 12 is orthogonal to the direction in which the terminal electrodes 13 are connected (the chip longitudinal direction), and the end of the coil 12 is led out to the chip end surface and connected to each terminal electrode 13.

In this laminated inductor, a plurality of magnetic green sheets having U-shaped, L-shaped, etc. coil conductors formed by a method such as screen printing are stacked in a predetermined order together with non-conductor-formed sheets and pressure-bonded. It is manufactured by firing a conductor paste for a terminal electrode and baking it after firing. The coil conductors that are adjacent to each other via the sheet are connected to each other through a through-hole portion formed in the sheet before forming the conductor to form the spiral coil 12. The uppermost and lowermost coil conductors have lead portions extending to the sheet ends, and the lead ends exposed at both ends of the chip are connected to the terminal electrodes 13.

[0005]

By the way, in the above-mentioned conventional laminated inductor, the four surfaces of the terminal electrode 13 can be used as the mounting surfaces, respectively. Therefore, when mounting this on the conductor pattern Za of the substrate Z, as shown in FIG. Two directions shown in FIG. 8, that is, a direction in which the winding centerline Y of the coil 12 is perpendicular to the substrate surface (see FIG. 7) and a direction in which the winding centerline Y of the coil 12 is parallel to the substrate surface (see FIG. 8) ) And occur.

In the mounting direction of FIG. 7 and the mounting direction of FIG. 8, a difference in the magnetic resistance with respect to the magnetic flux outside the chip occurs due to the difference in the positional relationship between the coil 12 and the substrate Z, and this causes a difference in the inductance. Will appear. In particular,
In a laminated inductor using a chip material having a low relative magnetic permeability, a large difference occurs in the magnetic resistance depending on the mounting direction, and a considerable difference appears in the inductance.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laminated inductor capable of obtaining stable characteristics even when the mounting direction of components changes depending on the shape and position of the terminal electrode. It is to provide a mounting structure.

[0008]

In order to achieve the above object, the present invention provides a laminated inductor mounting structure including a laminated inductor in which a coil is embedded in a chip having a laminated structure and a substrate on which the laminated inductor is mounted. The laminated inductor includes a rectangular parallelepiped chip, a coil embedded in the chip, a pair of terminal electrodes provided at both ends in the longitudinal direction of the chip, and a pair connecting the coil end and each terminal electrode. The chip has a lead-out conductor overlapping with the through-hole by printing a conductor paste on one surface of the green sheet in which the through-hole is formed at a predetermined position so as to partially fill the through-hole. The upper layer sheet, the lower layer sheet, and the green sheet on which the through holes are formed are partially filled with the conductive paste on one surface of the green sheet. The coil layer sheet on which a conductor for a coil whose end portion is overlapped with the through hole is formed is printed in the order of a plurality of lower layer sheets, a plurality of coil layer sheets corresponding to the number of coil turns, and a plurality of upper layer sheets. Is formed by firing a laminated body obtained by stacking and crimping, and each terminal electrode is formed by applying a conductor paste on both ends of the chip in the laminating direction and baking, and each terminal electrode is a portion that wraps around the side surface of the chip. And a coil having a predetermined number of turns by connecting a plurality of coil conductors of a plurality of coil layer sheets through conductor-filling through holes. The winding center line of the coil is parallel to the direction of connecting the terminal electrodes, and one lead portion connecting one end of the coil and one terminal electrode is A plurality of lower-layer sheets have a plurality of lead conductors stacked and connected through conductor-filling through-holes, and the lead-out portion has a portion exposed at one end surface of the lead-out conductor chip on one terminal electrode. The other lead-out portion that is connected and connects the other end of the coil to the other terminal electrode is configured by connecting a plurality of lead-out conductors included in a plurality of upper-layer sheets by stacking them through conductor-filling through holes, In the lead-out portion, a portion of the lead-out conductor exposed at the other end surface of the chip is connected to the other terminal electrode, while the substrate is a conductor on which one surface of the wrap-around portion of both terminal electrodes in the laminated inductor can be mounted. The laminated inductor is provided with a pattern, and the laminated inductor is mounted on the substrate such that one surface of a wraparound portion of both terminal electrodes faces the conductor pattern. To collect.

According to this laminated inductor mounting structure, since the coil center line is parallel to the direction connecting the terminal electrodes, a plurality of mounting directions are possible, or the shape and position of the terminal electrodes are changed and the mounting direction is changed. Even if the angle changes, the direction of the coil center line with respect to the substrate surface does not change.

[0010]

1 is a schematic sectional view of a laminated inductor according to the present invention.

In the figure, 1 is a rectangular parallelepiped chip made of a magnetic material or a non-magnetic material (insulating material), 2 is a spiral coil embedded in the chip 1, and 3 is a chip 1.
Is a pair of terminal electrodes provided on the longitudinal ends of the. The winding center line Y of the coil 2 is parallel to the direction (the chip longitudinal direction) connecting the terminal electrodes 3, and the end portion of the coil 2 is led out to the chip end surface and connected to each terminal electrode 3.

Even in the above laminated inductor, the four of the terminal electrodes 3
Since each of the surfaces can be used as a mounting surface, when mounting on the conductor pattern Za of the substrate Z, a direction different from the direction shown in FIG. 2 by 90 degrees occurs. But,
Since the winding centerline Y of the coil 2 is parallel to the direction connecting the terminal electrodes 3 (chip longitudinal direction), the direction of the winding centerline Y of the coil 2 with respect to the substrate surface does not change even if the mounting direction changes.

Therefore, the positional relationship between the coil 2 and the substrate Z can be maintained constant regardless of the mounting direction, a difference in magnetic resistance with respect to a magnetic flux outside the chip can be prevented, and a stable inductance can be obtained. You can

Now, a method of manufacturing the laminated inductor shown in FIG. 1 will be described with reference to FIGS.

In the production, first, the upper layer sheet A, the coil layer sheets B1 to B4, and the lower layer sheet C are prepared (see FIG. 3). Although the drawing shows one corresponding to one component, each actual sheet has a size capable of being taken in large numbers, and is cut into the component size after lamination and pressure bonding.

The upper layer sheet A is made of Fe ₂ O ₃ , NiO, Z.
It is prepared by forming a through hole h having a predetermined diameter at a predetermined position of a ferrite green sheet containing nO or CuO as a main component, and then forming a rectangular lead conductor Pa so as to overlap the through hole h. There is.

In the coil layer sheets B1 to B4, four types of U-shaped coils are formed so that the through holes h are formed at predetermined positions of the same ferrite green sheet as described above, and the ends thereof overlap the through holes h. It is created by forming the respective conductors Pb1 to Pb4. As the shape of the coil conductors Pb1 to Pb4, various non-circular conductors such as L-shape can be adopted in addition to the U-shape.

Similar to the upper layer sheet A, the lower layer sheet C has a through hole h having a predetermined diameter formed at a predetermined position of the ferrite green sheet, and then has a rectangular lead conductor Pc so as to overlap the through hole h. It is created by forming.

The through holes h are formed by laser light irradiation when the ferrite green sheet is supported by the film, and by die punching when the ferrite green sheet is not supported by the film. Also, the conductor P
a, Pb1 to Pb4, Pc are formed by thick film printing of a conductive paste containing a metal powder such as Ag by a method such as screen printing, and the through holes h are filled with a part of the printing paste at the time of printing. .

Next, each of the prepared sheets A, B1 to B
If C and C are attached to the film, remove them and
The layers are laminated in the order shown in, and they are pressure-bonded at a pressure of about 500 kg / cm ² . By the way, the upper and lower layer sheets A and C have the same number of sheets as the layer thickness, and the coil layer sheets B1 to B.
As for 4, the number corresponding to the number of coil turns is used.

Next, the laminated body of the respective sheets A, B1 to B4, C (see FIG. 4) is fired at a temperature corresponding to the metal component contained in the conductor, for example, in the case of Ag, a temperature of about 900.degree. As a result, the adjacent conductors Pa, Pb1 to Pb4, and Pc are connected to each other through the sheets A, B1 to B4, and C through the through-hole filling portion to form the spiral coil 2 in the stacking direction.

Next, the same conductor paste P as described above is applied to the end portion in the stacking direction of the chip 1 after firing (see FIG. 5), and this is baked at a temperature lower than the baking temperature to form the terminal. The electrode 3 is formed, and if necessary, it is plated with Sn—Pb or the like. Since the end portions (lead-out conductors Pa, Pc) of the coil 2 are led out to the chip end surface and exposed, the exposed portions are connected to the terminal electrodes 3.

[0023]

As described in detail above, according to the present invention,
Since the coil center line is parallel to the direction connecting the terminal electrodes (the chip longitudinal direction), the coil center line orientation with respect to the substrate surface does not change even if the mounting direction changes. Therefore, the positional relationship between the coil and the substrate can be maintained constant regardless of the mounting direction, and a stable inductance can be obtained by preventing a difference in magnetic resistance with respect to the magnetic flux outside the chip.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a laminated inductor according to the present invention.

FIG. 2 is a schematic perspective view of a laminated inductor according to the present invention.

FIG. 3 is a diagram showing a method of manufacturing the laminated inductor shown in FIG.

FIG. 4 is a perspective view showing a laminating and crimping process.

FIG. 5 is a perspective view showing a step of forming a terminal electrode.

FIG. 6 is a schematic sectional view of a conventional laminated inductor.

FIG. 7 is a diagram showing an example of mounting a conventional laminated inductor.

FIG. 8 is a diagram showing an example of mounting a conventional laminated inductor.

[Explanation of symbols]

1 ... Chip, 2 ... Coil, 3 ... Terminal electrode, Y ... Coil center line, A ... Upper layer sheet, Pa ... Lead-out conductor, B
1 to B4 ... Coil layer sheet, Pb1 to Pb4 ... Coil conductor, C ... Lower layer sheet, Pc ... Lead-out conductor.

Claims (5)

[Claims] 1. A laminated inductor mounting structure including a laminated inductor in which a coil is embedded in a chip having a laminated structure and a substrate on which the laminated inductor is mounted, wherein the laminated inductor is a rectangular parallelepiped chip and a chip. The chip has a coil embedded inside, a pair of terminal electrodes provided at both ends in the longitudinal direction of the chip, and a pair of lead portions connecting the coil end and each terminal electrode, and the chip has a through hole at a predetermined position. An upper layer sheet and a lower layer sheet on which a conductor paste is printed on one surface of the formed green sheet so that a part of the conductor paste is filled in the through hole to form a lead conductor overlapping the through hole,
A plurality of coil layer sheets each having a conductor for a coil formed by printing a conductor paste on one surface of the green sheet having the through holes so that a part of the conductor paste is filled in the through holes and forming coil conductors whose end portions overlap the through holes are formed. Lower layer sheet,
It is formed by stacking a plurality of coil layer sheets corresponding to the number of coil turns and a plurality of upper layer sheets in this order, and then pressing the resulting laminate to form a laminate. Each terminal electrode is a conductor on both ends of the chip in the stacking direction. The terminal electrodes are formed by applying and baking a paste, and each terminal electrode has a portion that wraps around the side surface of the chip and its four surfaces can be used as a mounting surface. The coil conductor is connected through the conductor-filled through hole to form a spiral having a predetermined number of turns, and the center line of the turn of the coil is parallel to the direction connecting the terminal electrodes. One of the lead-out portions for connecting with the terminal electrode is formed by connecting a plurality of lead-out conductors included in a plurality of lower-layer sheets in an overlapping manner through conductor-filling through holes. In the lead-out portion, the exposed portion of the lead-out conductor at one end surface of the chip is connected to one terminal electrode, and the other lead-out portion connecting the other end of the coil and the other terminal electrode is formed by a plurality of upper layer sheets. A plurality of lead-out conductors that are connected to each other through the conductor-filled through-holes, and the lead-out portion has a portion exposed at the other end surface of the lead-out conductor that is connected to the other terminal electrode. The substrate includes a conductor pattern on which one surface of the wraparound portions of both terminal electrodes in the laminated inductor can be mounted, and the laminated inductor has the substrate such that one surface of the wraparound portion of both terminal electrodes faces the conductor pattern. The multilayer inductor mounting structure is characterized by being installed in. 2. The upper layer sheet and the lower layer sheet of the laminated inductor have a through-hole partially filled with a conductor paste on one surface of a green sheet having a through hole of a predetermined diameter formed at a predetermined position. Is formed by forming a drawing conductor having a predetermined thickness that overlaps with the through hole by printing as shown in FIG.
A conductor paste is printed on one surface of a green sheet of a predetermined thickness having a through hole so that a part of the conductor paste is filled in the through hole to form a coil conductor of a predetermined thickness whose end overlaps with the through hole. The laminated inductor mounting structure according to claim 1, wherein the laminated inductor mounting structure is formed by: 3. A plurality of lead-out conductors forming each lead-out portion in the multilayer inductor have a size large enough to fill a part of the printing paste into the through holes when the conductor paste is printed, The laminated inductor mounting structure according to claim 1 or 2, wherein the conductor is connected by contact between the surface of the lead conductor and the end face of the conductor-filled through hole. 4. A lead-out portion formed of a plurality of lead-out conductors in the laminated inductor has a predetermined length, and each lead-out portion is parallel to the coil center line. The laminated inductor mounting structure according to any one of 1 to 3. 5. A lead-out portion formed of a plurality of lead-out conductors in the laminated inductor has a predetermined length, and a wrap-around portion of each terminal electrode faces a part of the corresponding lead-out portion. The laminated inductor mounting structure according to any one of claims 1 to 4, wherein: