JP2015053506A - Laminate inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate inductor with little variation of an L-value, in which core area change can be reduced.SOLUTION: A laminate inductor includes a laminate comprising a plurality of insulator layers A1 to A9, and a coil conductor spirally formed inside the laminate. The coil conductor has conductor patterns B1 to B5 formed on the insulator layer, and via hole conductors C1 to C4 penetrating through the insulator layer and electrically connecting the plurality of conductor patterns. The conductor patterns formed on one part of the insulator layer are C-shaped patterns B2 and B4 including four substantially rectangular peaks and one side partially notched, and the conductor pattern formed on the other part of the insulator layer is an I-shaped pattern B3 corresponding to one part of one side notched in the C-shaped patterns of the substantially rectangular shape. The insulator layer on which the C-shaped patterns are formed, and the insulator layer on which the I-shaped pattern is formed, are adjacent to each other at least at one part of the laminate.

Description

  The present invention relates to a multilayer inductor.

  In recent years, with the downsizing and multibanding of electronic equipment, multilayer inductors are desired to be downsized, have a high Q factor, have a narrow inductance step, and a narrow deviation. Conventionally, a multilayer inductor has formed a coil by combining a plurality of conductor patterns obtained from a plurality of screen masks or a plurality of conductor patterns obtained by shifting the same screen mask. FIG. 4 is a schematic exploded view of an example of a multilayer inductor according to the prior art. Conductor patterns B21 to B26 having predetermined shapes are respectively formed on insulator layers A22 to A27, and these are electrically connected to via hole conductors C21 to C25. Thus, a multilayer inductor including a coil conductor formed in a spiral shape in the multilayer body is configured. Here, depending on the accuracy of the screen mask and the mechanical accuracy, the stacking position of each pattern is displaced, and there is a possibility that the L value center displacement and L value variation of the inductor may occur through the change of the coil core area. there were.

  Patent Document 1 discloses an invention of a multilayer inductor characterized in that a core area formed by a part of a coil conductor is made smaller than a minimum core area formed by a remaining part. As a result, the variation in the L value caused by the laminating deviation of the conductor pattern depends on the number of turns of the coil conductor having a small core area, and the conductor pattern forming the coil conductor having a small core area is included in the entire conductor pattern. In view of the fact that it is only a part of the above, it is said that it is possible to provide a small-sized multilayer inductor having a small L value variation and a large allowable current value.

JP-A-11-340042

  In the configuration of Patent Document 1, it is difficult to provide a small-sized inductor because there is a limit to reducing the formation core area. It is an object of the present invention to provide a multilayer inductor that can reduce a change in core area and has a small L value variation.

As a result of intensive studies by the present inventors, the present invention having the following contents was completed.
The multilayer inductor of the present invention includes a multilayer body composed of a plurality of insulator layers, and a coil conductor formed in a spiral shape inside the multilayer body. The coil conductor has a conductor pattern formed in the insulator layer and a via-hole conductor that penetrates the insulator layer and electrically connects the plurality of conductor patterns. The conductor pattern formed on some of the insulator layers is a C-shaped pattern that includes four substantially rectangular vertices and lacks a part of one side. The conductor pattern formed on the other part of the insulator layer is an I-shaped pattern corresponding to a part of one side lacking in the C-shaped pattern in the substantially rectangular shape. The insulator layer on which the C-shaped pattern is formed and the insulator layer on which the I-shaped pattern is formed are adjacent to each other in at least a part of the laminate.

  Preferably, an external electrode is formed on the outer side of the laminate composed of the insulator layer, and the coil conductor has a lead part electrically connected to the external electrode and a coil body other than the lead part, and the conductor in the coil body The pattern consists only of a combination of the C-shaped pattern and the I-shaped pattern. The length of the I-shaped pattern is preferably 30% or less of the total length of the four sides of the substantially rectangular shape.

  According to the present invention, it is possible to obtain an inductor having a small core area change and a small variation in L value. Specifically, since the area defined by the substantially rectangular coil conductor is substantially determined by the C-shaped pattern, the area change due to the deviation of the conductor pattern formed on the plurality of insulator layers is reduced, and the L value The variation is reduced. Since the present invention can be applied even when the area of the substantially rectangular shape is small, it can contribute to the miniaturization of the multilayer inductor with small variation in L value.

It is a model exploded view of an example of the multilayer inductor by this invention. 1 is a schematic perspective perspective view of an example of a multilayer inductor according to the present invention. It is a graph which shows a computer simulation result. It is a schematic exploded view of an example of the multilayer inductor by a prior art.

  Hereinafter, the present invention will be described in detail with appropriate reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and in the drawings, the characteristic portions of the invention may be emphasized and expressed, so that the accuracy of the scale is not necessarily guaranteed in each part of the drawings. Not.

  The multilayer inductor of the present invention includes a multilayer body composed of a plurality of insulator layers, and a coil conductor formed in a spiral shape inside the multilayer body. FIG. 1 is a schematic exploded view of an example of a multilayer inductor according to the present invention. Conductor patterns B1 to B5 are formed on the insulator layers A2 to A6. Conductor patterns formed in different insulator layers are electrically connected to each other by via-hole conductors C1 to C4, and these via-hole conductors C1 to C4 pass through at least one insulator layer. In the drawing, the via-hole conductor penetrates the insulator layer at a location represented by a black circle. A coil conductor formed in a spiral shape is constituted by the conductor patterns B1 to B5 and the via-hole conductors C1 to C4.

  FIG. 2 is a schematic perspective perspective view of an example of the multilayer inductor according to the present invention. External electrodes D <b> 1 and D <b> 2 are formed on both ends of the above-described laminated body 12 made of a plurality of insulator layers. The conductor patterns B1 and B5 (not shown in FIG. 2) in FIG. 1 reach the end of the laminate composed of the insulator layers, and are electrically connected to the external electrodes D1 and D2 depicted in FIG. 2, respectively. It is connected. In the present invention, the conductor pattern for electrical connection to these external electrodes is called a lead-out portion. The conductor pattern other than the lead portion and the via-hole conductor are called a coil body. In the embodiment of FIG. 1, the conductor patterns B2 to B4 and the via hole conductors C2 and C3 constitute a coil body.

  According to the present invention, an insulator layer formed with a C-shaped pattern, which will be described later, and an insulator layer formed with an I-shaped pattern are adjacent to each other in at least a part of the laminate. Preferably, the coil body is composed only of a combination of a C-shaped pattern and an I-shaped pattern.

  The C-shaped pattern is a conductor pattern that includes four vertices of a substantially rectangular shape and lacks a part of one side of the substantially rectangular shape. In the embodiment of FIG. 1, the C-shaped pattern is represented by reference numerals B2 and B4. The substantially rectangular shape includes a rectangular shape as shown in FIG. 1 and an elliptical shape such as an elliptical shape. The fact that the C-shaped pattern includes four vertices having a substantially rectangular shape means that when the rectangle is approximated in a case where the four rectangular vertices are included as shown in FIG. 1 or when the substantially rectangular shape does not have a clear vertex. Includes a portion that can be recognized as a vertex. The C-shaped pattern lacks a part of one side of a substantially rectangular shape. Thus, the C-shaped pattern defines the majority of the core area.

  The I-shaped pattern corresponds to a part of one side lacking in the C-shaped pattern in a substantially rectangular shape. In the embodiment of FIG. 1, the I-shaped pattern is represented by reference numeral B3. In conformity with the actual shape of a substantially rectangular shape, the I-shaped pattern may be a straight line as shown in FIG. 1 or may be a curved shape forming a part of an elliptical shape. Preferably, the length of the I-shaped pattern is 30% or less, more preferably 10 to 20% of the total length of the four sides of the substantially rectangular shape. In other words, the length of the I-shaped pattern is preferably 3/7 or less of the length of the C-shaped pattern. As long as the effects of the present invention are not impaired, the length of the I-shaped pattern may be made longer than the length of the portion lacking in the C-shaped pattern to make the electrical connection more reliable.

  According to the present invention, the insulator layer in which the C-shaped pattern is formed is adjacent to the insulator layer in which the I-shaped pattern is formed in at least one place. As a result, a one-turn substantially rectangular coil is formed. At this time, since the C-shaped pattern mainly determines the core area, most of the accuracy of the core area depends on the accuracy of forming the C-shaped pattern (printing accuracy, etc.), and the accuracy of other adjacent patterns. The position accuracy at the time of stacking hardly affects the accuracy of the core area. In the multilayer inductor 10 according to the present invention, a change in inductance value can be reduced. In general, the inductance value L is proportional to (S / l) where l is the coil length and S is the core area. For this reason, in the multilayer inductor 10 in which the variation in the core area S is small, the change in inductance value is small. For this reason, it becomes easy to improve the accuracy of a core area as a whole multilayer inductor, and the variation in inductance can be reduced.

  In the embodiment of FIG. 1, one C-shaped pattern and one I-shaped pattern constitute a one-turn coil conductor, and one C-shaped pattern is further provided. This embodiment is described as “C-I-C”. According to the present invention, one C-shaped pattern and one I-shaped pattern may be laminated as C-C-C-I-, or at least one pattern may be formed. For example, C-C-I-C-C-I-... Or C-I-C-C-I-.

  According to the present invention, the coil body of the coil conductor only needs to have at least one pair of C-I adjacent laminated structures, for example, a partially U-shaped to adjust the value of the inductor. Patterns may be stacked. According to a preferred embodiment, all the coil bodies of the coil conductor are composed only of a combination of a C-shaped pattern and an I-shaped pattern.

  Hereinafter, more specific embodiments will be described, but this description does not limit the present invention. Here, the lamination direction of the multilayer inductor 10 is defined as the z-axis direction, the direction along the short side of the multilayer inductor 10 is defined as the x-axis direction, and the direction along the long side of the multilayer inductor 10 is defined as the y-axis direction. Define. The x axis, the y axis, and the z axis are orthogonal to each other. The multilayer inductor 10 includes a multilayer body 12 and external electrodes D1 and D2. Each of the external electrodes D1 and D2 is electrically connected to the coil conductor, and is provided on the side surface of the multilayer body 12 extending in the z-axis direction and facing each other. In the present embodiment, the external electrodes D1 and D2 are provided so as to cover two side surfaces located at both ends in the y-axis direction. The laminate 12 is configured by laminating insulator layers A1 to A9 in the z-axis direction. Insulator layers A1 to A9 are made of a material mainly composed of glass in this embodiment, and have a rectangular shape. The coil conductor has a spiral shape that rotates in the z-axis direction while turning, and includes conductor patterns B1 to B5 and via-hole conductors C1 to C4. The conductor patterns B1 to B5 are respectively formed on the main surfaces of the insulator layers A2 to A6, and are laminated together with the insulator layers A1 and A7 to A9. Each conductor pattern is made of a conductive material exemplified by Ag. Conductor patterns B1 and B5 are lead portions. The conductor pattern B1 and the coil conductor B5 are connected to the external electrodes D1 and D2, respectively. Conductor patterns B2 and B5 are connected via conductor pattern B3. By connecting the conductor patterns B1 and B2 and the conductor patterns B4 and B5, the external electrodes D1 and D2 are electrically connected. Each conductor pattern is connected by via-hole conductors C1 to C4.

  Here, the insulator layer may be made of a material containing glass as a main component, ferrite, dielectric ceramics, a magnetic material using soft magnetic alloy particles, or a resin mixed with magnetic powder.

  A typical manufacturing method of such a multilayer inductor will be exemplified. The present invention is not limited to this manufacturing method. A plurality of insulating material green sheets which are precursors of the insulating layers A1 to A9 are prepared. The green sheet is formed by applying an insulating material slurry mainly composed of glass or the like onto a film by a doctor blade method or the like. The thickness of the green sheet is not particularly limited, and is preferably 5 to 30 μm, for example 18 μm. Through holes are formed by laser processing or the like at predetermined positions of the insulating material green sheets to be the insulator layers A2 to A5, that is, positions where the via hole conductors C1 to C4 are to be formed. And the conductive paste which is the precursor of conductor pattern B1-B5 is printed with a screen mask etc. in each predetermined position of the insulating material green sheet used as insulator layer A2-A6. Examples of the main component of the conductive paste include metals such as silver and copper.

  Subsequently, the insulating material green sheets to be the insulator layers A1 to A15 are stacked in the order shown in FIG. 1, and pressure is applied in the stacking direction to press the insulating material green sheets. And after cut | disconnecting this press-bonded insulating material green sheet | seat in a chip unit, it bakes at predetermined temperature (for example, about 800 to 900 degreeC), and the laminated body 12 is formed. Subsequently, external electrodes D1 and D2 are formed on the laminate 12. Thereby, the electronic component 10 is formed. The external electrodes D1 and D2 are coated with electrode paste mainly composed of silver or copper on both end faces in the longitudinal direction of the laminate 12, and baked at a predetermined temperature (for example, about 680 ° C. to 900 ° C.). Furthermore, it forms by performing electroplating. For this electroplating, Cu, Ni, Sn, or the like can be used. The multilayer inductor 10 is completed through the above steps.

  The results of the computer simulation performed to clarify the effect of the present invention will be described below. Specifically, as a first model (example), a coil body is composed of a C-shaped pattern and an I-shaped pattern. Here, the I-shaped pattern had a length of 14% of one turn (one turn). The second model (comparative example) has a structure in which half-turn coil conductors are connected. The size of the first model and the second model is 0.6 mm × 0.3 mm × 0.3 mm, and the coil conductor is a silver electrode having a line width of 50 μm and a thickness of 8 μm.

  In this computer simulation, each model, the second model, and the second model when the positions of the coil conductor I-shaped pattern of the first model and the first model are moved ± 5 μm in the x direction and +5 μm in the y direction. The inductance values of the first and second models when the frequency of the signal input to the model when the one coil conductor of the model was moved by +5 μm in the x method and ± 5 μm in the y direction were 500 MHz were calculated. The results are shown in FIG. In the figure, the ◯ plot is the result when there is no deviation in the first model, the ♦ plot is the result when +5 μm is moved in the y direction of the first model, and the □ plot is the deviation when the second model is displaced. As a result, the ▲ plot is the result when +2 μm is moved in the y direction of the second model, and the ● plot is the result when −5 μm is moved in the y direction of the second model.

  In the first model (example), the maximum change amount of the inductance value when a signal having a frequency of 500 MHz is input is 0.7%, and in the second model (comparative example), the frequency has a frequency of 500 MHz. The maximum amount of change in the inductance value when a signal is input is 2.2%. It can be seen that the change in the inductance value is smaller in the example. Therefore, it has been found from this simulation that the inductance value change is small in the multilayer inductor having a structure in which the C-shaped pattern and the I-shaped pattern are adjacent to each other.

10 multilayer inductors, A1 to A9 insulator layers, B1 to B5 conductor patterns, C1 to C4 via-hole conductors, D1 and D2 external electrodes.

Claims (2)

A laminate comprising a plurality of insulator layers, and a coil conductor formed in a spiral shape inside the laminate, the coil conductor penetrating through a conductor pattern and an insulator layer formed in the insulator layer. A via hole conductor for electrically connecting the conductor pattern of
The conductor pattern formed on some of the insulator layers is a C-shaped pattern including four vertices of a substantially rectangular shape and lacking a part of one side, and the conductor patterns formed on the other part of the insulator layers are An I-shaped pattern corresponding to a part of one side lacking in the C-shaped pattern in the substantially rectangular shape,
The insulator layer in which the C-shaped pattern is formed and the insulator layer in which the I-shaped pattern is formed are adjacent to each other in at least a part of the laminate.
Multilayer inductor.   An external electrode formed on the outer side of the laminate, the coil conductor having a lead part electrically connected to the external electrode and a coil body other than the lead part, and the conductor pattern in the coil body is the C The multilayer inductor according to claim 1, comprising only a combination of a letter-shaped pattern and the I-shaped pattern.

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