JP2005039187A - Laminated coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate coil component which decreases in impedance small when a current is superposed. <P>SOLUTION: The laminate coil 1 comprises a magnetic body ceramic green sheet 13 provided with conductor patterns 9 for a coil, lead-out conductor patterns 11, and via holes 7 for inter-layer connection, a magnetic body ceramic green sheet 15 provided with via holes 7 for inter-layer connection, a magnetic body ceramic green sheet 14 provided with a plurality of conductor patterns 10 for coils, a magnetic body ceramic green sheet 16 for an external layer, etc. Then the conductor patterns 9 for coils and conductor patterns 10 for coils are electrically and alternately connected in series to form a spiral coil L1. The pitch coil P of the spiral coil L1 is set to ≥60 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laminated coil component, and more particularly to a laminated coil component such as a laminated inductor or a laminated impedance element.

  As a conventional multilayer coil component, for example, there is one having a structure as shown in FIG. The laminated coil 101 includes a magnetic ceramic green sheet 106 provided with a coil conductor pattern 105 on the surface and a magnetic ceramic green sheet 109 provided with a lead-out via hole 107. These sheets 106 and 109 are stacked and pressure-bonded to form a laminated body 110 (see FIG. 14), and then fired to form input / output external electrodes 111 and 112.

  The plurality of coil conductor patterns 105 are electrically connected in series via the interlayer connection via holes 104 to form the spiral coil L10 in the multilayer body 110. In this laminated coil 101, the coil axis of the helical coil L10 is parallel to the stacking direction of the laminated body 110, and both ends of the laminated body 110 are electrically connected to both ends of the helical coil L10. This is a so-called “vertically stacked vertically wound type” coil in which output external electrodes 111 and 112 are provided.

  The coil axis of the spiral coil is orthogonal to the stacking direction of the laminate, and input / output external electrodes electrically connected to both ends of the spiral coil are provided on both end faces of the laminate. As a so-called “vertical laminated horizontal winding” coil, there is one described in Patent Document 1.

  By the way, in the conventional laminated coil 101, in order to obtain a high impedance with a small size, the coil pitch P is reduced and the number of turns of the spiral coil L10 is increased. In order to reduce the coil pitch P, it is preferable to reduce the thickness of the sheet 106 and to narrow the interval between the coil conductor patterns 105. Specifically, the thickness of the sheet 106 was 10 to 50 μm.

  However, when the number of turns of the helical coil L10 is increased, there is a problem that the direct current resistance of the helical coil L10 increases and insertion loss increases.

  The laminated coil 101 is connected to a power supply line and used for noise reduction of a power supply line of an electronic device such as a large-capacity video recording device (DVD player), a digital camera, or a video. When a coil is used for noise reduction in the power line of an electronic device, a direct current of about 0.1 A flows through the power line.

However, as is generally known, the impedance of a laminated coil is reduced by current superposition. For example, currently widely used laminated coils (size: 1.6 mm × 0.8 mm × 0.8 mm) have an impedance of a standard value of 600Ω (100 MHz) without current superposition. Impedance drops to 40% or less of the standard value due to 1 A current superposition. In order to obtain a desired noise removal effect, an impedance of about 50% or more of the standard value is required in an actual usage situation (a situation where current is superimposed). Therefore, there has been a problem that a desired noise removal effect cannot be obtained.
JP 2002-252117 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated coil component that has a small impedance drop when current is superimposed.

In order to achieve the above object, a laminated coil component according to the present invention includes:
(A) a laminate formed by stacking a plurality of magnetic layers and a plurality of coil conductors;
(B) a helical coil formed inside the laminate by electrically connecting the coil conductors,
(C) the coil pitch P of the helical coil is 60 μm or more;
It is characterized by.

  The reason why the impedance is lowered due to the current superposition is that the magnetic substance is magnetically saturated. Therefore, the coil pitch P of the helical coil is set to 60 μm or more. As a result, the amount of magnetic material between the coil conductors is increased, and the density of magnetic flux distributed in the laminated body is reduced, so that magnetic saturation is less likely to occur.

  Furthermore, the laminated coil component according to the present invention is characterized in that the ratio of the gap G between the coil conductors adjacent to the coil axis direction with respect to the coil pitch P of the spiral coil is 45% or less.

  When the coil pitch P of the spiral coil is increased, the gap G between adjacent coil conductors is increased, and the leakage of magnetic flux from the gap G is increased. That is, when the coil pitch P is increased, the magnetic flux leaks from the gap G, so that it does not circulate around the entire spiral coil but circulates locally around the individual coil conductors. Therefore, the magnetic flux density is locally increased and magnetic saturation is likely to occur. Therefore, the ratio of the gap G between adjacent coil conductors to the coil pitch P of the spiral coil is set to 45% or less so that the gap G does not increase even if the coil pitch P increases. Thereby, leakage of magnetic flux from the gap G is suppressed, and local magnetic saturation is less likely to occur.

  In addition, the laminated coil component according to the present invention has a coil coil axis that is perpendicular to the stacking direction of the laminated body and is electrically connected to both ends of the laminated body at the ends of the helical coil. An output external electrode is provided.

  With the above configuration, the laminated coil component has a so-called vertical laminated horizontal winding structure. The coil pitch P of the spiral coil and the gap G between adjacent coil conductors can be arbitrarily and reliably determined by the arrangement of the plurality of coil conductors formed on the magnetic layer.

  In the laminated coil component according to the present invention, the coil axis of the spiral coil is orthogonal to the stacking direction of the laminate, and is electrically connected to the end of the spiral coil on the upper surface in the stacking direction of the laminate. An input / output external electrode is provided, and the input / output external electrode is made of a thin plate-like or foil-like metal bonded to the laminate.

  According to the present invention, since the coil pitch P of the spiral coil is set to 60 μm or more, the amount of magnetic material between the coil conductors is increased, and the magnetic flux density distributed in the laminated body is reduced, so that magnetic saturation hardly occurs. . As a result, it is possible to provide a laminated coil component with a small impedance drop when current is superimposed.

  Further, by setting the ratio of the gap between coil conductors G adjacent in the coil axis direction to 45% or less of the coil pitch P of the spiral coil, the gap G is reduced even if the coil pitch P is increased. . Therefore, leakage of magnetic flux from the gap G can be suppressed, local magnetic saturation is unlikely to occur, and impedance reduction during current superposition can be further suppressed.

  Hereinafter, embodiments of the laminated coil component according to the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the laminated coil 1 is provided with a magnetic ceramic green sheet 13 provided with a plurality of coil conductor patterns 9, lead-out conductor patterns 11, and interlayer connection via holes 7, and interlayer connection via holes 7. A magnetic ceramic green sheet 15, a magnetic ceramic green sheet 14 provided with a plurality of coil conductor patterns 10, an outer layer magnetic ceramic green sheet 16, and the like.

  The magnetic ceramic green sheet is obtained by, for example, mixing a Fe—Ni—Cu ferrite powder together with a binder or the like into a sheet shape by a method such as a doctor blade method. The coil conductor patterns 9 and 10 and the lead conductor pattern 11 are made of Ag, Pd, Cu, Au, alloys thereof, or the like, and are formed by a method such as screen printing. In addition, the via hole 7 for interlayer connection which is a coil conductor is formed by forming a hole in the via hole using a laser beam or the like and filling the hole with a conductive paste such as Ag, Pd, Cu, Au or an alloy thereof. It is formed.

  The coil conductor pattern 9 and the coil conductor pattern 10 are arranged in parallel on the sheets 13 and 14, respectively. The interlayer connection via hole 7 has an axial center arranged in the stacking direction of the sheets 13 to 16 and is connected. Then, the end portions of the coil conductor pattern 9 are electrically connected to the end portions of the coil conductor pattern 10 through the interlayer connection via holes 7, whereby the coil conductor pattern 9 and the coil conductor pattern 10 are alternately arranged. Are connected in series to form a helical coil L1.

  Both ends of the spiral coil L1 are electrically connected to the lead conductor pattern 11. The lead conductor patterns 11 are exposed on the left and right sides of the sheet 13, respectively.

  After the sheets 13 to 16 are stacked and pressure-bonded, they are integrally fired to form a laminated body 21 having a rectangular parallelepiped shape as shown in FIG. Input / output external electrodes 22 and 23 are formed on the left and right end faces of the laminate 21. The external electrodes 22 and 23 are formed by a method such as coating baking, sputtering, or vapor deposition. The lead conductor pattern 11 is connected to the external electrodes 22 and 23, respectively.

  In the laminated coil 1 having the above configuration, a spiral coil L1 whose coil axis is orthogonal to the stacking direction of the laminated body is disposed inside the laminated body 21. The input / output external electrodes 22 and 23 electrically connected to both end portions of the spiral coil L1 are disposed on the left and right end surfaces of the laminated coil 1. Therefore, the laminated coil 1 is a so-called “vertically laminated horizontally wound type” coil. The vertically laminated horizontally wound type coil 1 has a feature that the coil pitch P of the spiral coil L1 and the gap G between adjacent coil conductors can be arbitrarily and reliably determined.

  That is, in the case of the “vertically laminated vertically wound type” coil shown in FIG. 13, the coil pitch P and the gap G between adjacent coil conductors are determined by the thickness of the magnetic ceramic green sheet. However, the thickness of the magnetic ceramic green sheet is limited depending on the processing conditions when the ceramic green sheet is molded or pressed, and may not be set arbitrarily thick.

  On the other hand, in the case of the “vertically laminated horizontal winding type” coil 1, the coil pitch P and the gap G between adjacent coil conductors are the intervals between the coil conductor patterns 9 and 10 formed on the surfaces of the sheets 13 and 14. It is determined by the interval between the via holes 7 formed in the sheet 15. The interval between the coil conductor patterns 9 and 10 and the interval between the via holes 7 are not limited by processing conditions, and can be set arbitrarily wide.

  Here, the laminated coil 1 in which the coil pitch P of the helical coil L1 and the inter-coil gap G for coils adjacent to each other in the coil axial direction were variously changed was experimentally manufactured.

  The size of the laminated coil 1 is 1.6 mm × 0.8 mm × 0.8 mm. Then, as shown in FIG. 3, by changing the arrangement pitch P of the coil conductor patterns 9 and 10, the coil pitch P of the spiral coil L1 is six types of 20 μm, 40 μm, 60 μm, 80 μm, 125 μm, and 250 μm. I made a prototype. In addition, by changing the conductor widths of the coil conductor patterns 9 and 10, three types of coil conductor gaps G of 15 μm, 30 μm, and 45 μm were prototyped.

  The impedance remaining rate at a measurement frequency of 100 MHz was measured while superimposing a direct current of 0.1 A on each of the prototype laminated coils 1. The measurement results are shown in the graph of FIG. From the graph, it can be seen that increasing the coil pitch P increases the residual impedance ratio. This is because when the coil pitch P is increased, the magnetic flux density distributed in the laminated body 21 is reduced, so that magnetic saturation is less likely to occur.

  Then, it can be seen that in order to ensure a practically required impedance residual rate of 50%, the coil pitch P should be 60 μm or more (see the graph in the case where the coil conductor gap G is 15 μm). Thereby, this laminated coil 1 can be incorporated and used as a noise filter in the power supply line of an electronic device. That is, even if a direct current of about 0.1 A flows through the power supply line, the impedance of the laminated coil 1 is not easily lowered, and a desired noise removal effect is maintained.

  In addition, when the coil pitch P reaches 250 μm, the impedance remaining ratio of all the laminated coils 1 becomes about 70%. A laminated coil (ferrite bead) in which a linear conductor was provided in a magnetic ceramic was prepared, and the impedance residual ratio when a direct current of 0.1 A was superimposed was measured to be about 70%. Since this ferrite bead can be considered to have an infinite coil pitch P, it can be seen that even if the coil pitch P is 250 μm or more, the impedance remaining rate cannot be further improved.

  Furthermore, it can be seen from the graph that the impedance residual ratio increases by reducing the gap G between the coil conductors. This is because when the gap G between the coil conductors becomes small, the leakage of the magnetic flux from the gap G decreases, and the magnetic flux circulates around the entire spiral coil L1, and magnetic saturation is less likely to occur. That is, it is preferable to design the coil pitch P to be large and the coil conductor gap G to be small. Thereby, the impedance remaining ratio of the laminated coil 1 can be further increased.

  Furthermore, if the gap between coil conductors G is reduced, the inductance remaining rate when a direct current is passed through the laminated coil 1 can also be increased. Then, next, the laminated coil 1 which made various changes in the gap G between the coil conductors adjacent to the spiral coil L1 in the coil axis direction was manufactured.

  The coil pitch P of the spiral coil L1 is 290 μm, the number of turns is 9.5 turns, and the gap G between the coil conductors is 0 μm, 65 μm (ratio of the gap G to the coil pitch P: 22.4%), 105 μm (ratio: 36.2%), 125 μm (ratio: 43.1%), 140 μm (ratio: 48.3%), and 225 μm (ratio: 77.6%) were prototyped.

  Here, in setting the gap between coil conductors G, the gap G1 between the coil conductor patterns 9 and between the coil conductor patterns 10 and the gap G2 between the interlayer connection via holes 7 are basically equal. . The cross-sectional shape of the via hole 7 may be an ellipse or a circle. However, the elliptical shape can increase the inner diameter of the spiral coil L1 and increase the inductance of the laminated coil 1.

  Further, the laminated coil 1 having a coil conductor gap G of 0 μm, as shown in FIGS. 5 and 6, is formed by forming the coil conductor patterns 9 and 10 adjacent to each other in the horizontal direction in a plan view. The upper gap G1 is 0 μm. In this case, the gap G2 between the interlayer connection via holes 7 was set to 65 μm. A direct current was passed through each of the prototype laminated coils 1 to measure the residual inductance rate. The measurement result is displayed by a solid line 31 in FIG. In the graph of FIG. 7, the horizontal axis is the ratio of the gap G to the coil pitch P, and the vertical axis is the current value (= rated current) at which the residual inductance ratio is 70%.

  From the graph, it can be seen that when the ratio of the gap G is 45% or less, the rated current is high and the inductance remaining rate is high. By reducing the gap G, leakage of magnetic flux from the gap G is suppressed, and the magnetic flux density in the spiral coil L1 is made uniform. This is because the laminated coil 1 is less likely to be magnetically saturated and the inductance is less likely to decrease.

  Further, it was examined how the rated current changes when the gap G1 between the coil conductor patterns 9 and 10 is fixed and the gap G2 between the interlayer connection via holes 7 is changed. The coil conductor patterns 9 and 10 have a stepped structure and a gap G1 of 0 μm. Then, the cross-sectional shape of the interlayer connection via hole 7 is changed to an ellipse and the length in the longitudinal direction is changed, and the gap G2 is 65 μm (ratio 22.4%), 105 μm (ratio: 36.2%), 125 μm (ratio: 43). 0.1%), 140 μm (ratio: 48.3%), and 225 μm (ratio: 77.6%), 5 types of laminated coils 1 were made on a trial basis.

  A direct current was passed through each of the prototype laminated coils 1 to measure the residual inductance rate. The measurement result is displayed by a solid line 32 in FIG. It can be seen that when the ratio of the gap G2 to the coil pitch P is 45% or less, the rated current is high and the inductance remaining rate is high.

  Further, it was examined how the rated current changes when the gap G2 between the interlayer connection via holes 7 is fixed and the gap G1 between the coil conductor patterns 9 and 10 is changed. The gap G2 between the interlayer connection via holes 7 was 225 μm. The gaps G1 between the coil conductor patterns 9 and the coil conductor patterns 10 are 0 μm, 65 μm (ratio 22.4%), 105 μm (ratio: 36.2%), 125 μm (ratio: 43.1%), Six types of laminated coils 1 having a size of 140 μm (ratio: 48.3%) and 225 μm (ratio: 77.6%) were produced as prototypes.

  A direct current was passed through each of the prototype laminated coils 1 to measure the residual inductance rate. The measurement result is displayed by a solid line 33 in FIG. It can be seen that when the ratio of the gap G1 to the coil pitch P is 45% or less, the rated current is high and the inductance remaining rate is high.

  Furthermore, as shown in FIG. 8, by arranging the interlayer connection via holes 7 in a staggered manner, the gap G1 between the coil conductor patterns 9 and the coil conductor patterns 10 and the gap G2 between the interlayer connection via holes 7 are arranged. And apparently 0 μm. In this case, the rated current of the laminated coil 1 was 390 mA, which was the highest.

  Further, as shown in FIG. 9, instead of providing the lead conductor pattern 11, a lead-out via hole 42 is provided in the outer layer sheet 16, and both ends of the spiral coil L <b> 1 are provided on one surface of the multilayer body 21 via the lead-out via hole 42. You may make it pull out to.

  After the sheets 13 to 16 are stacked and pressure-bonded, they are integrally fired to form a laminate 21 having a rectangular parallelepiped shape as shown in FIG. Input / output external electrodes 45 and 46 are formed on the left and right sides of one surface of the laminate 21. The external electrodes 45 and 46 are adhered to one surface of the laminate 21 using a conductive adhesive or the like, and the lead-out via holes 42 are connected to the external electrodes 45 and 46, respectively.

  As shown in FIG. 11, the laminated coil 1 is mounted on a circuit board 51 provided with conductor lands 52 and 53 by wire bonding. That is, the laminated coil 1 is placed on the circuit board 51 with the external electrodes 45 and 46 facing upward, and the external electrodes 45 and 46 and the conductor lands 52 and 53 are electrically connected by the bonding wires 54. In this case, the external electrodes 45 and 46 are thin Cu (Ag or Au) plates or Cu foils (for example, those having a thickness of about 20 μm) plated with Au, or thin Cu plates or Cu foils. It consists of what gave Ni-Au plating.

  Alternatively, as shown in FIG. 12, the laminated coil 1 is mounted on a circuit board 61 provided with conductor lands 62 and 63 with solder or a conductive adhesive. That is, the laminated coil 1 is placed on the circuit board 61 with the external electrodes 45 and 46 facing down, and the external electrodes 45 and 46 and the conductor lands 62 and 63 are electrically connected by solder or a conductive adhesive 64. The In this case, the external electrodes 45 and 46 are made of a thin Cu plate or Cu foil subjected to Ni—Sn plating, or a thin Cu plate or Cu foil subjected to Ni—Au plating.

  The laminated coil 1 having the above configuration can be formed by wire bonding external electrodes 45 and 46 obtained by applying Au plating to an inexpensive Cu plate or Cu foil. Furthermore, when a Cu plate is used, the Cu plate suppresses unevenness on the surface of the laminated body 21, so that the wire bonding connectivity is improved. Moreover, since the external electrodes 45 and 46 are formed only on one side of the multilayer body 21, the height of the multilayer coil 1 can be reduced.

  In addition, this invention is not limited to the said embodiment, It can change variously within the range of the summary. Examples of the laminated coil component include a laminated impedance element, a laminated LC filter, and a laminated transformer in addition to the laminated inductor.

  Further, as shown in FIGS. 13 and 14, the laminated coil component is configured such that the coil axis of the helical coil L <b> 10 is parallel to the stacking direction of the laminated body 110, and the helical coil is formed on both end faces of the laminated body 110. A so-called “vertically stacked vertically wound type” in which input / output external electrodes 111 and 112 electrically connected to both ends of L10 may be provided. Alternatively, it may be a so-called “horizontal laminated horizontal winding type” in which input / output external electrodes 111 and 112 are provided on the upper and lower surfaces of the laminated body 110 having the structure shown in FIG. .

  Moreover, although the said embodiment demonstrated by the example of the individual product, it cannot be overemphasized that in the case of mass production, you may manufacture in the state of the mother laminated block containing several laminated coil components. Furthermore, although the embodiment has been described by taking a laminated coil having a component size of 1.6 mm × 0.8 mm × 0.8 mm as an example, the same effect can be obtained for coil components having other component sizes.

  Moreover, when manufacturing a laminated coil component, it is not necessarily limited to the method of integrally baking after laminating | stacking the magnetic body ceramic sheet | seat provided with the conductor pattern for coils and a via hole. A magnetic ceramic sheet that has been fired in advance may be used. Moreover, you may manufacture a laminated coil component with the construction method demonstrated below. That is, after applying a paste-like magnetic ceramic material by printing or the like to form a magnetic layer, a paste-like conductive material is applied on the magnetic layer to form a coil conductor pattern or via hole. Form. Further, a paste-like magnetic ceramic material is applied from above to form a magnetic layer. By successively applying in this manner, a coil component having a laminated structure can be obtained.

1 is an exploded perspective view showing an embodiment of a laminated coil component according to the present invention. FIG. 2 is an external perspective view of the multilayer coil component shown in FIG. 1. The plane perspective view of laminated coil components. The graph which shows the impedance remaining rate of laminated coil components. The disassembled perspective view which shows the modification of laminated coil components. Sectional drawing of the laminated coil component shown in FIG. The graph which shows the rated current from which the inductance remaining rate of laminated coil components will be 70%. The disassembled perspective view which shows another modification of a laminated coil component. The disassembled perspective view which shows another modification of laminated coil components. FIG. 10 is an external perspective view of the multilayer coil component shown in FIG. 9. The front view which shows the state which mounted the laminated coil components shown in FIG. 10 on the circuit board. The front view which shows the state which mounted the multilayer coil component shown in FIG. 10 on another circuit board. The exploded perspective view which shows the conventional laminated coil components. FIG. 14 is an external perspective view of the multilayer coil component shown in FIG. 13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated coil 7 ... Via hole for interlayer connection 9, 10 ... Conductor pattern for coil 13-16 ... Magnetic ceramic green sheet 21 ... Laminated body 22, 23, 45, 46 ... External electrode for input / output 42 ... Via hole for extraction L1 ... Helix coil P ... Coil pitch G ... Gap between conductors for coil

Claims (4)

A laminate formed by stacking a plurality of magnetic layers and a plurality of coil conductors;
A spiral coil formed in the laminated body by electrically connecting the coil conductor;
The coil pitch P of the spiral coil is 60 μm or more,
A laminated coil component characterized by   2. The laminated coil component according to claim 1, wherein the ratio of the gap G between the coil conductors adjacent in the coil axis direction to the coil pitch P of the spiral coil is 45% or less.   The coil axis of the spiral coil is orthogonal to the stacking direction of the multilayer body, and external electrodes for input / output are provided on both end faces of the multilayer body and electrically connected to the end portions of the spiral coil. The multilayer coil component according to claim 1 or 2, wherein the multilayer coil component is provided.   An input / output external electrode electrically connected to an end of the spiral coil is provided on the upper surface of the stack in the stack direction of the stack, and the coil axis of the spiral coil is orthogonal to the stack direction of the stack. 3. The multilayer coil component according to claim 1, wherein the external electrode for input / output is made of a thin plate-like or foil-like metal bonded to the laminate.

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