JP2004071962A - Laminated inductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated inductor in which a resonance frequency is selectively set and great impedance is obtained. <P>SOLUTION: An insulating film 1 and a conductor pattern 2 is laminated in an appropriate order to form a chip body 3 with an incorporated coil 20 to which the conductor pattern 2 is spirally linked internally. External electrodes 4 and 4 are formed on a counter face 2 along an axial line of the coil 20 to comprise a longitudinal wiring type laminated inductor 10. Packaging may be performed in the attitude of making a coin axis fall down to be parallel to a wafer. Inside the chip body 2, an electrode conductor 5 is provided to be connected to the external electrode 4. The electrode conductor 5 is formed approximately rectangular, located on a layer outside a coil layer and set to be superimposed all over the area of a coil pattern form. The electrode conductor 5 is connected to the external electrode 4 on the opposite side of the connection side of the nearby conductor pattern 2. Thus, electrostatic capacitance occurs in a gap with the coil 20, and the element becomes equivalent with a resonance circuit wherein capacitive loads are connected parallel. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer inductor, and more specifically, to an improvement in a conductor pattern of a multilayer inductor having a coil in which a conductor pattern is spirally connected in a chip body.
[0002]
BACKGROUND OF THE INVENTION
As is well known, electronic components called chip components are miniaturized into small pieces without providing lead terminals for use in surface mounting, and one of them is a laminated inductor which is an inductance element.
[0003]
The laminated inductor forms a rectangular chip body containing a coil in which a conductor pattern is spirally connected by laminating an insulating film and a conductor pattern in an appropriate order, and furthermore, on two opposing surfaces of the chip body. , And external electrodes respectively connected to both ends of the built-in coil are provided.
[0004]
For example, a ceramic material is used for the insulating film, and the chip body is baked at a predetermined temperature after completing the lamination. The external electrode is formed by, for example, dipping. In other words, the chip is formed by immersing the corresponding portion of the chip body in a conductive paste such as silver, so that the external electrodes are formed so that the conductive film covers the four surfaces adjacent to the electrode surfaces in a predetermined manner. It has a form having a peripheral portion that goes around the surface. As a result, any of the four adjacent surfaces can be surface-mounted, and the chip body can be mounted on the substrate even if the mounting surface changes due to the chip body lying down. Can be simplified.
[0005]
As a method of forming a chip body (laminated body), there are a sheet laminating method in which a conductor pattern is formed and stacked on an insulating sheet, and a printing laminating method in which an insulating paste and a conductive paste are alternately applied and laminated. In any case, a spirally connected coil pattern and a drawing pattern thereof are formed inside the laminate.
[0006]
In addition, since the external electrodes are provided on the two opposing surfaces of the chip body, the external electrodes have directivity in relation to the built-in coil. That is, there are a vertical winding type formed on two opposing surfaces along the axis of the built-in coil and a horizontal winding type formed on two opposing surfaces opposite to the coil axis. In the horizontal winding type, the coil axis is oriented horizontally. In the case of the vertical winding type, when the chip body is turned over, the coil axis is also turned down and turned to the side. Therefore, it is necessary to pay attention to mounting where the direction of the magnetic field is restricted on the substrate.
[0007]
By the way, in such a laminated inductor, there is a demand for appropriately changing the resonance frequency. That is, it is desired to selectively set the resonance frequency of the inductance element based on the operating conditions of the circuit to be applied. However, since this resonance frequency takes an eigenvalue by physically forming an element, measures have been required.
[0008]
Further, although the laminated inductor is an inductance element, there is a demand that the element has a large impedance Z due to the operating conditions of a circuit to be applied. Here, in order to increase the impedance Z, there is a method of increasing the inductance L. However, increasing the number of turns to increase the inductance L is difficult to manufacture with a chip component that requires a reduction in size.
[0009]
The present invention has been made in view of the above background, and has as its object to solve the above-described problems, to provide a multilayer inductor that can selectively set a resonance frequency and obtain a large impedance. Is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the multilayer inductor according to the present invention, an insulating film such as a ceramic and a conductor pattern are laminated in an appropriate order, thereby incorporating a coil in which the conductor pattern is spirally connected. It is assumed that the laminated inductor includes a chip body having a shape, and external electrodes respectively connected to ends of the coil are provided on two opposing surfaces of the chip body. Then, an electrode conductor connected to the external electrode is provided in the chip body, and the connection of the electrode conductor is connected to the external electrode on the side opposite to the connection side of the nearby conductor pattern.
[0011]
Further, the electrode conductor may be arranged on a layer outside the pattern layer forming the coil, and may be configured to overlap the entire area of the pattern shape forming the coil or the area partially covering the inner space.
[0012]
Furthermore, the electrode conductor is disposed on a layer outside the pattern layer forming the coil, so as to overlap the pattern shape forming the coil, or disposed near the winding end of the coil, It can also be arranged between layers inside the pattern layer to be formed.
[0013]
Therefore, in the present invention, an electrode conductor connected to the external electrode is provided in the chip body, and this is connected to the external electrode on the side opposite to the connection side of the nearby conductor pattern. Which is a load capacitance connected in parallel with the inductance element. Therefore, the element becomes equivalent to a parallel resonance circuit having an inductance L and a capacitance C, and the value of the capacitance can be adjusted by appropriately setting the area of the electrode conductor.
[0014]
Further, as another solution means, by laminating an insulating film of ceramic or the like and a conductor pattern in an appropriate order, a rectangular chip body including a coil in which the conductor pattern is spirally connected is provided. In the chip body, external electrodes connected to the ends of the coil are provided on two opposing surfaces along the axis of the coil. In a laminated inductor, two opposing surfaces opposing the axis of the coil are provided for displaying directions. It can be configured to provide a directional marker.
[0015]
Then, on the premise of the above another solution, a conductor film for shielding is provided on a layer outside the pattern layer forming the coil, and the conductor film covers the whole or at least the inside of the pattern shape forming the coil. Superimposed on the area covering the airspace. Further, the conductor film can be arranged near a surface layer of the chip body. With such a configuration, both ends of the coil are covered with the electrode conductors, so that the magnetic flux of the coil can be shielded.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a first embodiment of the present invention. In the present embodiment, the laminated inductor 10 has the coil 20 built in the chip body 3 formed in a substantially rectangular shape, and the external electrodes connected to the two opposing surfaces of the chip body 3 and the ends of the built-in coil 20 respectively. The external electrodes 4 and 4 are formed on two opposing surfaces along the axis of the built-in coil 20 and employ a so-called vertical winding type. In the present embodiment, it is assumed that the mounting is rotated 90 degrees horizontally and the coil axis becomes parallel to the substrate, and FIG. 1 shows a posture in which the coil axis is turned sideways.
[0017]
The chip body 3 is formed by laminating an insulating film 1 made of ceramic or the like and the conductor pattern 2 in an appropriate order, thereby forming a coil 20 in which the conductor pattern 2 is spirally connected. Bake hard.
[0018]
The external electrodes 4 and 4 are formed by dipping. In other words, by immersing the corresponding portion of the chip body 3 in a conductive paste such as silver, the external electrodes 4 and 4 are in a state where the conductive film covers the four surfaces adjacent to the original electrode surfaces by a predetermined length. The film is formed, and has a form having a peripheral portion 40 which goes around four adjacent surfaces.
[0019]
In the first and last layers, the conductor pattern 2 forming the coil 20 is formed by extending the lead conductor 6 from the end of the coil pattern to the corresponding edge, and electrically connecting the external electrode 4 via the lead conductor 6. The connection is made.
[0020]
In the present invention, the electrode conductor 5 connected to the external electrode 4 is provided inside the chip main body 3, and the capacitance is generated between the electrode conductor 5 and the coil 20. In other words, the electrode conductor 5 is formed in a substantially rectangular shape, and is arranged on a layer outside the pattern layer forming the coil 20, and as shown in FIG. Set to superimpose. As shown in FIG. 2A, the electrode conductor 5 is connected to the external electrode 4 on the side opposite to the side where the nearby conductor pattern 2 is connected to the external conductor 4.
[0021]
As described above, the electrode conductor 5 connected to the external electrode 4 is provided in the chip body 3, and this is connected to the external electrode 4 on the opposite side to the connection side of the nearby conductor pattern 2, so that the A capacitance occurs between them. This is a load capacitance connected in parallel to the inductance element. For this reason, the element becomes equivalent to a parallel resonance circuit having an inductance L and a capacitance C. The capacitance value can be adjusted by appropriately setting the area of the electrode conductor 5, and the resonance frequency can be selectively set and appropriately set. Can be lowered. In this case, even if the number of turns of the coil 20 is small, a larger impedance than before can be obtained because of parallel resonance in which the capacitance C is intentionally added to the inductance L.
[0022]
In addition, since both ends of the coil 20 are covered with the electrode conductors 5 and 5, a secondary effect that the magnetic flux of the coil 20 can be shielded and interference with other components on the substrate can be prevented can be obtained.
[0023]
(Measurement result)
In order to confirm the effect of the present invention, the frequency characteristics of the first embodiment were measured. At this time, a comparative example having no electrode conductor 5 was prepared, and Q (Quality factor) was measured under the same conditions. The graph shown in FIG. 3 is a Q-frequency characteristic, and the measured value of the comparative example is indicated by an imaginary line p, and the measured value of the first embodiment is indicated by a solid line r. The number of turns of the coil was 5 turns, and the inductance value was 10 mH.
[0024]
As a result, the resonance frequency was 3700 MHz in the comparative example, and was 2000 MHz in the first embodiment. Then, it was confirmed that the resonance frequency characteristic of 2000 MHz was equivalent to that of the normal configuration of 22 nH.
[0025]
Therefore, it is clear that the value of the capacitance can be adjusted and the resonance frequency can be appropriately lowered, and a large impedance can be obtained by parallel resonance in which the capacitance C is added to the inductance L.
[0026]
The configuration of the electrode conductor 5 is not limited to the above-described first embodiment, and may be configured as shown in each of FIGS. 4 to 7. That is, FIGS. 4A and 4B show a second embodiment of the present invention. In the second embodiment, a configuration is adopted in which the electrode conductor 5 is arranged on a layer outside the pattern layer forming the coil 20 and overlaps a region partially covering the inner space of the pattern shape forming the coil 20. As described above, since the electrode conductor 5 partially covers the inner air space of the coil 20, the shield of the magnetic flux can be appropriately performed by adjusting the covered area. Note that the other configuration and operation and effect are the same as those of the above-described embodiment, and the corresponding members are denoted by the same reference numerals and detailed description thereof will be omitted.
[0027]
FIGS. 5A and 5B show a third embodiment of the present invention. In the third embodiment, a configuration is adopted in which the electrode conductor 5 is arranged on a layer outside the pattern layer forming the coil 20 and is further superimposed on the pattern shape forming the coil 20. In this case, since the electrode conductor 5 follows the coil pattern shape, the inner space of the coil 20 is not covered, so that a capacitance component can be added without shielding magnetic flux. Note that the other configuration and operation and effect are the same as those of the above-described embodiment, and the corresponding members are denoted by the same reference numerals and detailed description thereof will be omitted.
[0028]
FIGS. 6A and 6B show a fourth embodiment of the present invention. In the fourth embodiment, a configuration is adopted in which the electrode conductor 5 is arranged near the winding end of the coil 20. Here, the electrode conductor 5 is set so as not to overlap with the coil 20. However, since the electrode conductor 5 is arranged near the winding end, a capacitance is generated between the two, and the value of the capacitance is appropriately adjusted. Can be set.
[0029]
Since the electrode conductor 5 is provided on the same layer as the layer on which the winding end pattern of the coil 20 is formed, both can be formed in the same step in manufacturing, so that the number of steps is not increased, which is advantageous in terms of cost. Note that the other configuration and operation and effect are the same as those of the above-described embodiment, and the corresponding members are denoted by the same reference numerals and detailed description thereof will be omitted.
[0030]
FIGS. 7A and 7B show a fifth embodiment of the present invention. In the fifth embodiment, a configuration is adopted in which the electrode conductor 5 is disposed between layers inside the pattern layer forming the coil 20. As described above, the electrode conductor 5 may be arranged inside the coil 20, and the capacitance can be obtained even between the coil patterns. Note that the other configuration and operation and effect are the same as those of the above-described embodiment, and the corresponding members are denoted by the same reference numerals and detailed description thereof will be omitted.
[0031]
FIG. 8 shows another example. In this example, a configuration is provided in which a directional marker for displaying a direction is provided. That is, as in the first embodiment shown in FIG. 1, the laminated inductor 10 incorporates the coil 20 in the chip body 3 formed in a substantially rectangular shape, and also incorporates the coil 20 in two opposing surfaces of the chip body 3. A configuration is provided in which external electrodes 4 and 4 that are respectively connected to the ends of the coil 20 are provided. The external electrodes 4 and 4 are formed on two opposing surfaces along the axis of the built-in coil 20 and employ a so-called vertical winding type. The mounting is rotated 90 degrees horizontally so that the coil axis is parallel to the substrate. Therefore, directional markers 7, 7 for displaying directions are provided on two opposing surfaces opposing the axis of the coil 20.
[0032]
Next, a manufacturing method of this embodiment will be described. The chip body 3 which is a laminate is formed by stacking a conductor pattern on an insulating sheet made of a ceramic material (dielectric material) by a sheet lamination method, and a conductor paste is formed by forming a conductor pattern. Perform screen printing. In the production of chip components, a work laminate having a size corresponding to a plurality of chip components is manufactured from the viewpoint of productivity, and after sufficiently drying the work laminate, the work laminate is cut into individual pieces and fired. Note that the laminate may be formed by a print lamination method in which an insulating paste and a conductor paste are alternately applied.
[0033]
Specifically, the process procedure shown in FIG. 9 is adopted, first, the directional marker 7 is formed (FIG. 9A), and an insulating sheet is stacked thereon to form a dummy layer (insulating film 1) (FIG. 9A). FIG. 9 (b).
[0034]
Next, a conductor paste is applied using a coil pattern plate having an extension extending to one edge to form the lead conductor 6 and the coil pattern 26 (FIG. 9C). Then, an insulating layer (insulating film 1) is formed by stacking the insulating sheets, a first through hole 81 is provided at a predetermined position overlapping the tip of the lower coil pattern (FIG. 9D), and a conductive paste is applied to the layer. Thus, a first pattern 21 is formed, which has a substantially U-shape extending from the through hole 81 and bending at two corners (FIG. 9E).
[0035]
Further, an insulating layer (insulating film 1) is formed by stacking insulating sheets, and a third through hole 83 is provided at a predetermined position overlapping with the lower end of the coil pattern (FIG. 9 (f)), and a conductive paste is applied to the layer. Thus, a third pattern 23 is formed, which has a substantially U-shape extending from the third through hole 83 and bending at two corners (FIG. 9G).
[0036]
Then, an insulating sheet (insulating film 1) is formed by stacking insulating sheets, a second through-hole 82 is provided at a predetermined position overlapping the tip of the lower coil pattern (FIG. 9 (h)), and a conductive paste is applied to the layer. Thus, a second pattern 22 is formed, which has a substantially L-shape extending from the second through hole 82 and bending at one corner (FIG. 9 (i)).
[0037]
Further, returning to the step (d), these steps (d) to (i) are repeated to obtain the coil 20 extended to a predetermined winding turn.
[0038]
Then, each layer is similarly formed on the opposite side of the coil 20, that is, after forming the second through hole 82 (FIG. 9 (h)), a coil pattern plate having an extension extending to the other edge is used. Then, a conductor paste is applied to form the lead conductor 6 and the coil pattern 26 (FIG. 9 (j)). Further, an insulating sheet is stacked to form a dummy layer (insulating film 1) (FIG. 9 (k)), and a directional marker 7 is formed thereon (FIG. 9 (l)).
[0039]
Thereafter, the dried work laminate is cut into individual chips, degreased, and fired to remove burrs. Then, dipping is performed on the end surface of the fired chip body 3 to form a film in such a manner that the conductive film covers the adjacent four surfaces in a predetermined manner, and Ni plating and Su plating are sequentially performed to form the external electrodes 4. , 4 to obtain a multilayer inductor 10.
[0040]
As described above, since the directional markers 7, 7 for displaying the direction are provided on the two opposing surfaces opposing the axis of the coil 20, the posture in which the surface without the directional markers 7, 7 is vertical is the normal mounting posture. In a directional alignment process such as a product inspection process, there is a high possibility that the postures that can be taken are one in two and naturally aligned. As a result, labor can be saved.
[0041]
In addition, the alignment of the elements can be facilitated by directing the surface without the directional markers 7 and 7 to the top and bottom, so that the directional markers 7 and 7 are attached to the corresponding surface (side surface) of the chip body 3 at this time. It just needs to exist, and its position, size, etc. do not require precision. Therefore, it can be easily formed and has an advantage in cost.
[0042]
Further, as a modified example of the example shown in FIG. 7, it can be configured as shown in FIGS. First, as shown in FIGS. 10A and 10B, conductive films 9 for shielding are provided on layers outside the pattern layer forming the coil 20, respectively. As shown in FIG. 10B, the conductor films 9 and 9 have a configuration in which the conductor films 9 and 9 are superimposed over the entire area of the pattern shape forming the coil 20.
[0043]
Since the conductor films 9 and 9 are disposed at both ends of the coil 20 as described above, it is possible to prevent the magnetic flux from leaking to the outside and to perform a magnetic shield. Therefore, the influence from the periphery and the influence on the periphery can be suppressed on the board on which this is mounted. Of course, the shape of the conductor films 9 and 9 may be appropriately set, but from the surface of the magnetic shield, it is preferable that the shape is superimposed on at least a region covering the inner space of the pattern shape forming the coil 20.
[0044]
FIG. 11 shows another modification. In this example, a configuration is adopted in which the conductor films 9 and 9 are arranged near the surface layer of the chip body 3. In this case, since the conductor films 9 and 9 for magnetic shielding are arranged near the surface layer of the chip body 3, it is possible to perform magnetic shielding while suppressing interference and interruption of the magnetic field of the coil 20, thereby reducing the Q value. Deterioration can be suppressed.
[0045]
Further, the shape and color of the conductor films 9 and 9 arranged near the surface layer of the chip body 3 become visible from the outside, so that the conductor films 9 and 9 can be used as directional markers. There is no need to provide the directional marker, which is advantageous in terms of cost.
[0046]
As described above, by providing the directional markers for indicating the directions on the two opposing surfaces opposing the axis of the coil, the posture in which the surface without the directional markers is upside down becomes the normal mounting posture, and the product inspection process is performed. The possible orientations in the directional alignment process become one in two, and the probability of natural alignment increases. In addition, the alignment of the elements can be facilitated by directing the surface without the directional marker to the top and bottom, and the directional marker only needs to be present on the corresponding surface (side surface). Does not need precision. Therefore, it can be easily formed and has an advantage in cost. As a result, labor can be saved.
[0047]
Furthermore, by providing a conductor film for shielding on the outer layer of the coil pattern layer, magnetic flux can be prevented from leaking to the outside, and magnetic shielding can be performed. The influence on the surroundings can be suppressed.
[0048]
Further, by arranging the conductor film for the magnetic shield near the surface layer of the chip body, the magnetic shield can be performed while suppressing the interference and interruption of the magnetic field of the coil, so that the deterioration of the Q value can be suppressed. .
[0049]
In addition, the shape and color of the conductive film placed near the surface layer of the chip body can be seen from the outside, so that these conductive films can be used as directional markers, without providing a dedicated directional marker. This is advantageous in terms of cost.
[0050]
【The invention's effect】
As described above, in the laminated inductor according to the present invention, the electrode conductor connected to the external electrode is provided in the chip body, and this is connected to the external electrode on the opposite side to the connection side of the nearby conductor pattern. A capacitance is generated between the coil and the coil, which becomes a load capacitance connected in parallel with the inductance element. Therefore, the element becomes equivalent to a parallel resonance circuit having an inductance L and a capacitance C, and the value of the capacitance can be adjusted by appropriately setting the area of the electrode conductor. Therefore, the resonance frequency can be selectively set, and can be appropriately reduced. In this case, even if the number of windings of the coil is small, a larger impedance than before can be obtained because of the parallel resonance in which the capacitance C is intentionally added to the inductance L.
[0051]
Further, since both ends of the coil are covered with the electrode conductors, the magnetic flux of the coil can be shielded, and interference with other components on the substrate can be prevented.
[0052]
Furthermore, if a configuration is adopted in which the inner air space of the coil pattern shape is partially covered by the electrode conductor, the shielding of the magnetic flux can be appropriately performed by adjusting the covered area. In addition, when a configuration in which the electrode conductor is superimposed on the coil pattern shape is employed, a capacitance component can be added without shielding magnetic flux. Furthermore, by arranging the electrode conductor near the winding end of the coil, a capacitance is generated between the winding end and the coil end. Therefore, the value can be set appropriately and the pattern can be formed in the same step. Further, by arranging an electrode conductor between layers inside the coil pattern layer, capacitance can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view of a multilayer inductor according to a first embodiment.
FIG. 2A is a cross-sectional view of the multilayer inductor shown in FIG.
(B) is a plan view of the electrode conductor.
FIG. 3 is a graph showing frequency characteristics.
FIG. 4A is a cross-sectional view of a multilayer inductor according to a second embodiment.
(B) is a plan view of the electrode conductor.
FIG. 5A is a cross-sectional view of a multilayer inductor according to a third embodiment.
(B) is a plan view of the electrode conductor.
FIG. 6A is a cross-sectional view of a multilayer inductor according to a fourth embodiment.
(B) is a plan view of the electrode conductor.
FIG. 7A is a cross-sectional view of a multilayer inductor according to a fifth embodiment.
(B) is a plan view of the electrode conductor.
FIG. 8 is a perspective view illustrating an example of a multilayer inductor.
FIG. 9 is a plan view showing steps of manufacturing the laminated inductor of FIG. 8 in order.
FIG. 10A is a cross-sectional view illustrating another example of the multilayer inductor.
(B) is a plan view of the shield conductor.
FIG. 11 is a sectional view showing still another example of the multilayer inductor.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 insulating film 2 conductor pattern 3 chip body 4 external electrode 5 electrode conductor 6 lead conductor 7 directional marker 9 conductor film 10 laminated inductor 20 built-in coil 21 first pattern 22 second pattern 23 third pattern 26 coil pattern 40 peripheral part 81 First through hole 82 Second through hole 83 Third through hole

Claims (5)

By laminating an insulating film such as a ceramic and a conductor pattern in an appropriate order, a rectangular chip body containing a coil in which the conductor pattern is spirally connected is provided therein, and the opposing two surfaces of the chip body are In a laminated inductor provided with external electrodes respectively connected to the ends of the coil,
An electrode conductor connected to the external electrode is provided in the chip body, and the connection of the electrode conductor is connected to an external electrode on a side opposite to a connection side of a nearby conductor pattern. The electrode conductor is disposed on a layer outside a pattern layer forming the coil,
2. The multilayer inductor according to claim 1, wherein the multilayer inductor overlaps an entire area of the pattern shape forming the coil or an area partially covering the inner space. 3. The electrode conductor is disposed on a layer outside a pattern layer forming the coil,
The multilayer inductor according to claim 1, wherein the multilayer inductor is superimposed on a pattern shape forming the coil. The multilayer inductor according to claim 1, wherein the electrode conductor is disposed near a winding end of the coil. The multilayer inductor according to claim 1, wherein the electrode conductor is disposed between layers inside the pattern layer forming the coil.

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