JP3359802B2 - Multilayer inductor and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor utilizing an electromagnetic induction effect, and more particularly to a laminated inductor in which coil conductors are formed by lamination, and a method of manufacturing the same.

More specifically, the present invention relates to a chip-type multilayer inductor, and more specifically, to an open-magnetic-path type multilayer chip inductor. It is about improving markers for clarity.

[0003]

2. Description of the Related Art In recent years, very small multilayer inductors, which are formed by laminating coil-shaped conductors, so-called multilayer chip inductors, have been widely known. This multilayer chip inductor has, for example, a chip size of 2.0
× 1.25 (mm), and the number of turns of the coil is 5 turns.

[0004] Among the types of multilayer chip inductors, those having a low inductance value mainly used for high frequency circuits use a material having a magnetic permeability close to 1 as the material of the chip body. Therefore, as shown in FIG. 5B, the low-inductance multilayer chip inductor has an open magnetic path type structure in which the magnetic flux 53 generated by the internal coil conductor 52 leaks out of the chip body 51. Have.

[0005] To add an explanation here, an inductor having a small inductance value is used for the high frequency circuit. For this reason, the number of turns of the coil conductor 52 is reduced, and a smaller inductance value is obtained by using a non-magnetic material instead of a magnetic material for the chip body 51. Therefore, the chip body 5
Since a material having low magnetic permeability is used for the magnetic flux 53, the magnetic flux 53 leaks out of the chip body 51.

Incidentally, FIG. 5A shows that:
This is a closed magnetic circuit type multilayer chip inductor having a structure in which a magnetic flux 55 generated by an internal coil conductor 54 does not leak out of a chip body 56.

As described above, in the open-circuit-type multilayer chip inductor, since the magnetic flux 53 leaks out of the chip body 51, the influence of an object around the chip body 51 is reduced.
You will inevitably receive it.

For this reason, for example, as shown in FIG. 6, when the chip main body 51 is mounted on a circuit board, the direction of circulation of the internal coil conductor 52 with respect to the circuit board 61 is either horizontal or vertical. The influence of the circuit board 61 on the magnetic flux 53 differs depending on the above. In addition, there is a problem that if there is another component 62 around the magnetic flux 53, the magnetic flux 53 is further affected differently.

That is, the influence of the magnetic flux 53 by the circuit board 61 or other components 62 is different depending on the arrangement posture of the chip body 51, and as a result, the influence of the magnetic flux 53 is different, and the chip body 51 is different. There is a problem that the predetermined inductance value changes.

Furthermore, the coil conductor 52 inside the chip is
As shown in FIGS. 7A and 7B, there is an asymmetry between the conductor 71 at the start of winding and the conductor 72 at the end of winding. Leakage becomes asymmetric, and as a result, due to the difference in the influence of the circuit board and other surrounding components,
There is a problem that a difference occurs in the inductance value.

In order to solve the above-mentioned problems, a conventional open-magnetic-path type multilayer chip inductor shown in FIG.
(A), a marker 82 is provided at a predetermined position of a laminated chip inductor 81 as a product. More specifically, a single marker 82 indicating the winding start or end position of the coil conductor 52 is attached to the surface of the multilayer chip inductor 81 so that the conductor 71 at the beginning or end of winding of the coil conductor 52 is clear. Had been.

In other words, when the laminated chip inductor 81 is mounted on the circuit board, the marker 82 is always used to keep the effect of the leaked magnetic flux and the circuit board or other components around the circuit always constant. By mounting them at the same position, the above-mentioned problems were solved.

[0013]

As described above, a conventional open-magnetic-path-type multilayer chip inductor is provided with one marker in order to regulate its mounting posture.

On the other hand, when measuring the electrical characteristics of the multilayer chip inductor only, or when taping and packaging the multilayer chip inductor for mounting, the coil conductor in the multilayer chip inductor may have a fixed direction, such as starting or ending. It had to be aligned. In other words, when examining the electrical characteristics of the multilayer chip inductor itself, the markers need to be aligned in a certain direction. In addition, in order to align and tap the markers in a certain direction, a process of aligning the markers in a certain direction is required.

[0015] The direction regulating step for making the direction of one marker uniform is a very time-consuming step, and even when automated, there is a problem that the number of chip parts processed per time is small and productivity is extremely low. there were.

For example, as is apparent from FIG. 8B, even when the orientation of the multilayer chip inductor 81 is the same, only eight types of markers are used as indicated by a to h depending on the positions of the markers. Attitude will exist.
Therefore, the step of uniformly aligning the direction of one marker includes at least eight types of postures a, b, c, and
.., H, it is necessary to align them in one type of posture a.

Here, a process of aligning the markers in a certain direction will be schematically described. In this case, a device called a parts feeder (not shown) is generally used as a device for arranging chip components in a line. The parts feeder vibrates the dish-shaped container by putting parts such as chip parts in the dish-shaped container. In the dish-like container, a path through which parts can pass is formed from the bottom of the dish-like container along the peripheral wall of the dish-like container. The road has a wall on the outer peripheral side, but has no wall on the inner side. When the dish is vibrated, the chip components move and follow the path along the dish. At first, it starts to move in various postures, but the chip part in an unstable posture falls down from the road and falls to the bottom of the dish-shaped container because the road is narrow and there is no wall on one side. Only chip components in a stable position continue to progress.

The stable posture described here means that when the chip component is the multilayer chip inductor 81 of FIG.
Only the eight types shown in (B) that progress in the longitudinal direction in the eight types of postures continue to progress to the final stage.

In the final stage, the marker is image-recognized by the CCD camera, and the unsuitable one is dropped off the road by the information from the CCD camera. The only thing that passes here is the one where the markers are aligned in a certain direction.

As described above, the step of uniformly aligning the direction of one marker is a very time-consuming process.
Even in the case of automation, there is a problem that the number of processing of chip components per time is small and productivity is extremely low.
The present invention has been developed to solve this problem.

[0021]

According to the laminated inductor of the present invention, an inner conductor is formed in a coil shape by lamination, and a start end and an end of the inner conductor are formed to form a pair of lead conductors. In a multilayer inductor in which conductors are led out of each other and connected to external electrodes,
Each marker indicating each position of the lead conductor is formed on the surface of the multilayer inductor.

The marker may be formed outside the surface of the multilayer inductor, or may be formed slightly inside the surface of the multilayer inductor so that the marker can be seen from outside.

In the laminated inductor of the present invention, the inner conductor is formed in a coil shape by the green sheet laminating step and the firing step thereof, and the start end and the end of the internal conductor are formed to form a pair of lead conductors. In a laminated inductor where these lead conductors are connected to external electrodes, use a raw sheet that disappears by firing,
A marker indicating the position of the lead conductor is formed on the raw sheet.

[0024] The green sheet that disappears by firing may disappear at the ceramic firing temperature of the laminated inductor.

In the method of manufacturing a laminated inductor according to the present invention, the inner conductor is formed into a coil shape by the green sheet laminating step and the firing step thereof, and each end of the inner conductor is formed to form a pair of lead conductors. In the method for manufacturing a laminated inductor in which the lead conductors extend in opposite directions, a marker indicating the position of the lead conductor is provided with the marker so that the marker is disposed outside the surface of the laminated inductor. The method is characterized by having a step of arranging the sheets.

In the method for manufacturing a laminated inductor according to the present invention, the inner conductor is formed into a coil shape by the step of laminating the raw sheets, and each end of the inner conductor is formed to form a pair of lead conductors. In the method for manufacturing a laminated inductor in which a conductor is connected to an external electrode, a raw sheet having the marker is arranged such that a marker indicating a position of the lead-out conductor is disposed inside a surface of the laminated inductor. Characterized by having a step of

In addition, in the laminated inductor manufacturing method according to the present invention, the inner conductor is formed into a coil shape by the green sheet laminating step and the firing step, and each end of the inner conductor is formed into a pair of lead conductors. And a method of manufacturing a laminated inductor in which these lead conductors are connected to external electrodes, at least a step of forming a marker indicating the position of the lead conductor on a raw sheet that disappears by firing. It is characterized by having.

[0028]

Therefore, according to the present invention, in the laminated inductor, the markers are arranged at two positions of the winding start and end of the coiled internal conductor, respectively. Are located symmetrically, and the symmetry of the entire multilayer inductor is maintained, and as a result, the directionality of the multilayer inductor is reduced by half.

In other words, according to the present invention, the posture of the multilayer inductor can be reduced by half from eight to four, and as a result, the process of aligning the orientation of the markers at a constant level is greatly improved. The number of chip parts processed per time has greatly improved, and the productivity has become extremely high.

[0030]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example with reference to the accompanying drawings, in which: FIG.

FIGS. 1A and 1B are drawings showing one embodiment of the laminated inductor according to the present invention, wherein FIG. 1A is a perspective view of the laminated inductor, and FIG. 1B is a perspective view showing various postures of the laminated inductor. . FIG. 2 is an explanatory view showing one embodiment of the method for manufacturing a laminated inductor according to the present invention, and FIG.
FIG. 4 is an explanatory diagram showing a second embodiment of the method for manufacturing a laminated inductor according to the present invention. FIG. 4 is an explanatory diagram showing a third embodiment of the method for manufacturing a laminated inductor according to the present invention.

FIG. 1A is a perspective view showing the entire laminated inductor 11 according to one embodiment of the present invention. As shown, the laminated inductor 11 is formed in a rectangular shape. Reference numeral 12 denotes a coil-shaped internal conductor.
Is formed at the center inside the multilayer inductor 11. 1
Reference numerals 3 and 14 denote lead conductors and lead conductors 13 and 14
Are connected to each end of the internal conductor 12, respectively. In other words, the lead conductors 13 and 14 start and end the winding of the coil-shaped inner conductor 12, and extend in the opposite directions. External electrodes 15 and 16 for external terminals are formed on both outer sides of the laminated inductor 11, respectively. The external electrode 15 is connected to the lead conductor 13, and the external electrode 16 is connected to the lead conductor 14.

A marker 17 is formed on the upper outside of the multilayer inductor 11. The marker 17 indicates the position of the lead conductor 13. A marker 18 is formed at a lower portion of the outside of the multilayer inductor 11.
The marker 18 indicates the position of the lead conductor 14.

In the present embodiment as described above, the inner conductor 12 of the laminated inductor 11 appears to have no symmetry at first glance, but is symmetric with respect to one axis 19 passing through the center of the coil pattern of the inner conductor 12. It is understood that there is a property. In consideration of this, when the positions of the markers 17 and 18 are set to two positions of the winding start and the winding end of the internal conductor 12,
The two markers 17 and 18 are positioned symmetrically with respect to the axis 19, and as a result, it is possible to reduce the directionality while maintaining the overall symmetry.

That is, the inner conductor 12, the lead conductor 1
By making the positions of the markers 17 and 18 at two positions by utilizing the symmetry of 3 and 14, the postures a and b in FIG.
As shown by b, c, and d, the directionality could be reduced to four, and the productivity of the above-described direction regulation step could be increased.

Here, a manufacturing process of the laminated inductor 11 described with reference to FIG. 1 will be described with reference to FIG. The chip size of the multilayer inductor 11 is, for example,
2.0 × 1.25 (mm), and the number of turns of the coil is 5 turns.

In FIG. 2, first, the raw sheet 21 on which the marker 18 has been printed is placed upside down.
The raw sheet 22 without printing is laminated on the raw sheet 22. Then, the raw sheet 23 with the lead conductor 14 is laminated on the raw sheet 22, and the raw sheet 24 having a part of the internal conductor 12 is laminated on the raw sheet 23. Further, another raw sheet 25 having a part of the internal conductor 12 is laminated on the raw sheet 24, and as shown, the raw sheets 24 and 25 are repeatedly laminated, and as shown in FIG. The raw sheet 26 with the lead conductor 13 is laminated, and the raw sheet 26
The raw sheet 27 without printing is laminated on the raw sheet 27. Finally, the raw sheet 28 on which the marker 17 is printed is laminated.
The laminated inductor 11 was manufactured by pressure bonding and firing.

In the case of FIG. 2, for example, the marker 1
The printed raw sheets 21 and 28 of 8, 17 are 30 μm.
m, the thickness of the raw sheets 21, 27 to be superimposed on the raw sheets 21, 28 with the markers was 200 μm, the other raw sheets 23, 24, 25, 26 were 150 μm, and the number of layers was 12 layers. .

FIG. 3 is an explanatory view showing a method of manufacturing another laminated inductor, but it is needless to say that a manufacturing process substantially similar to that of FIG. 2 is provided. First, a raw sheet 31 on which the marker 18 is printed is placed, a raw sheet 32 without printing is laminated on the raw sheet 31, and then a raw sheet 33 with a lead conductor 14 is laminated on the raw sheet 32. A raw sheet 34 having a part of the internal conductor 12 is laminated on the sheet 33, and another raw sheet 35 having a part of the internal conductor 12 is laminated on the raw sheet 34 as shown in the drawing. Then, the raw sheets 34 and 35 are repeatedly laminated, and a raw sheet 36 with the lead conductor 13 is laminated on the last raw sheet 35, and a raw sheet 37 on which the marker 17 is printed is laminated. Raw sheet 37
The raw sheet 38 without printing is laminated on the
After firing, a laminated inductor is manufactured.

In this case, since the raw sheets 31 and 38 are thin, for example, 30 μm in thickness, the marker 1
7, 18 can be seen through and fully visible. An advantage of this embodiment that the marker can be recognized through the ceramic sheet is that the markers 18 and 17 do not disappear due to abrasion or the like.

FIG. 4 is an explanatory view showing the third manufacturing method. In this case also, there are steps substantially similar to those in FIG.
The characteristic feature is that the raw sheet 41 disappears by firing.
The raw sheet 41 with the marker 18 is printed on the raw sheet 41, two raw sheets 42 without printing are laminated on the raw sheet 41, and then the raw sheet 42 with the conductor 14 drawn out is placed on the raw sheet 42. 43, a raw sheet 46 with the lead conductor 13 is laminated, a raw sheet 47 without printing is laminated on the raw sheet 46, and finally, a raw sheet 48 on which the marker 17 is printed.
The other steps are the same as in FIGS. 2 and 3 and are omitted.

The raw sheet 41 which disappears at the temperature at which the ceramic is fired was formed of, for example, a polyvinyl butyral film, an acrylic resin film or the like.

Specifically, the disappearing raw sheet 41 is formed by forming a solution prepared by dissolving 100 g of polyvinyl butyral powder in 600 g of toluene on a PET film, and Marker 18 was printed with cobalt oxide ink.

[0044]

According to the present invention as described above, a marker having a simple structure is formed on the surface of a laminated inductor, in which each marker indicating the position of a pair of lead conductors formed inside the laminated inductor is formed. As a result, the number of stacked conductor positions can be reduced by half, and the productivity of the process of aligning the stacked inductors in the same position can be dramatically improved. In addition, the production cost of the multilayer chip inductor can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a laminated inductor according to the present invention, in which (A) is a perspective view of the laminated inductor, and (B) is a perspective view showing various postures of the laminated inductor.

FIG. 2 is an explanatory view showing one embodiment of a method for manufacturing a laminated inductor according to the present invention.

FIG. 3 is an explanatory view showing a second embodiment of the method for manufacturing a laminated inductor according to the present invention.

FIG. 4 is an explanatory view showing a third embodiment of the method for manufacturing a laminated inductor according to the present invention.

FIG. 5 is a schematic cross-sectional view for explaining types of a multilayer inductor.

FIG. 6 is a schematic sectional view for explaining a mounting example of a multilayer inductor.

FIG. 7 is a schematic cross-sectional view for explaining a change in magnetic flux of the multilayer inductor.

FIG. 8 is a drawing showing a conventional laminated inductor, and FIG.
1 is a perspective view showing a conventional laminated inductor, and FIG. 2B is a perspective view showing various postures of the laminated inductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Multilayer inductor 12 Inner conductor 13, 14 Leader conductor 15, 16 External electrode 17, 18 Marker 19 Axis

Continuation of the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 17/00 H01F 27/00 H01F 41/02 H01G 13/00 331

Claims (6)

(57) [Claims] An internal conductor is formed in a coil shape by lamination, and a start end and an end of the internal conductor are formed to form a pair of lead conductors, and these lead conductors are led out from each other and connected to an external electrode. Wherein each marker indicating a position of each of the lead conductors is formed on a surface of the multilayer inductor. 2. An inner conductor is formed in a coil shape by a raw sheet laminating step and a firing step thereof, and a start end and an end of the inner conductor are formed to form a pair of lead conductors. A laminated inductor connected to an external electrode, wherein a raw sheet that disappears by firing is used, and a marker indicating the position of the lead conductor is formed on the raw sheet to form a marker on the chip surface. A multilayer inductor characterized by the following. 3. An inner conductor is formed in a coil shape by a raw sheet laminating step and a firing step thereof, and a start end and an end of the inner conductor become lead conductors, and these lead conductors are connected to external electrodes. The method of manufacturing a laminated inductor according to claim 1, wherein the raw sheet having the marker is arranged such that the marker indicating the position of the lead conductor is disposed outside the surface of the laminated inductor near or far from each lead conductor. A method for manufacturing a multilayer inductor, comprising the steps of: 4. An inner conductor is formed in a coil shape by a raw sheet laminating step and a firing step thereof, and a start end and an end of the inner conductor are formed to form a pair of lead conductors. A method of manufacturing a laminated inductor connected to an external electrode, wherein the marker indicating the position of the lead conductor is disposed inside the surface of the laminated inductor at a position near or far from each lead conductor. A method for manufacturing a laminated inductor, comprising a step of arranging a raw sheet having 5. An inner conductor is formed in a coil shape by a green sheet laminating step and a firing step, and a start end and an end of the inner conductor are formed to form a pair of lead conductors,
And a method for manufacturing a laminated inductor in which these lead conductors extend in directions opposite to each other, including a step of forming a marker indicating the position of the lead conductor on a raw sheet that disappears at a temperature at which ceramic is fired. A method for manufacturing a multilayer inductor, comprising: 6. The method according to claim 5, wherein the sheet that disappears at the temperature at which the ceramic is fired is a sheet selected from the group consisting of a polyvinyl butyral film and an acrylic resin film.