JP2006041320A - Laminated inductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, high-inductance laminated inductor capable of preventing the mechanical strength and electrical characteristics from deteriorating by means of a simple and inexpensive manufacturing method. <P>SOLUTION: Inside a laminate 1 in which a plurality of insulating layers 2 are laminated, a linear conductive pattern 3 is interposed between the adjacent insulating layers 2-2, and the conductive pattern 3 is electrically connected for forming a coil pattern 11. In this case, both the ends of the conductive pattern 3 are led onto the surface of the laminate 1, and the lead and that of an adjacent conductive pattern 3 are electrically connected on the surface of the laminate 1 via a connection pattern 4, made of a metal-plated film deposited with both the leads as the starting points, thus constituting a laminated inductor 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multilayer inductor.

  FIG. 8 is a cross-sectional view showing a conductor pattern of a conventional multilayer inductor.

  In the figure, a laminated inductor 30 includes a linear conductor pattern 33 interposed between adjacent insulating layers 32 in a laminated body formed by laminating a plurality of insulating layers 32, and these conductor patterns 33 are connected to via holes. The coil pattern 41 is formed by being electrically connected by the conductor 34.

That is, the current input through the via-hole conductor 34a from the outside is the via-hole conductor 34a, the conductor pattern 33a, the via-hole conductor 34b, the conductor pattern 33b, the via-hole conductor 34c, the conductor pattern 33c, the via-hole conductor 34d, the conductor pattern 33d, and the via-hole conductor 34e. In this order, a predetermined inductance is obtained by spirally flowing inside the multilayer body 31 (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-241941

  However, according to the multilayer inductor 30, the conductor pattern 33 is electrically connected by the via-hole conductor 34. That is, since it is necessary to form the through hole in a different position for each layer of the insulating layer 32 and then fill the conductive paste to form the conductor portion 34 to be a via-hole conductor, the process is complicated and the cost increases. It was the cause. In addition, with the filling of the conductive paste, the thickness of the conductive paste varies, particularly in the vicinity of the through-holes. Due to this, the deformation of the laminated body 31 increases during lamination, and internal defects such as delamination during firing and There was a problem of causing a change in product characteristics.

  In addition, when a displacement occurs between the conductor pattern 33 and the conductor portion 34 that becomes the via-hole conductor, there is a problem that the connection state between the conductor pattern 33 and the via-hole conductor 34 is deteriorated and the resistance value is increased.

  Further, in order to reduce the size and increase the inductance of the multilayer inductor 30, it is desirable to reduce the thickness of the insulating layer 2 so as to increase the number of times the current flows spirally in the multilayer body 31, and the conductor pattern. In order to improve the connection state between 33 and the via-hole conductor 34, it is desirable to increase the diameter of the via-hole conductor 34. However, when the diameter of the via-hole conductor 34 is increased and the thickness of the insulating layer 32 is reduced, Since it becomes difficult to hold the conductive paste in the through hole, there is a limit to downsizing and high inductance of the multilayer inductor 30.

  The present invention has been devised in view of the above-mentioned problems, and its object is to realize a reduction in size and increase in inductance by a simple and inexpensive manufacturing method, as well as mechanical strength and electrical characteristics. It is an object of the present invention to provide a multilayer inductor that can prevent a decrease.

  The multilayer inductor according to the present invention includes a linear conductor pattern interposed between adjacent insulating layers in a multilayer body formed by laminating a plurality of insulating layers, and electrically connecting these conductor patterns. A metal plating in which both end portions of the conductor pattern are led out to the surface of the multilayer body and the lead portions of the conductor pattern adjacent to the lead portion are precipitated starting from both lead portions in the coil pattern formed It is characterized in that it is electrically connected on the surface of the laminate through a connection pattern made of a film.

  According to the present invention, both end portions of the conductor pattern are led out to the surface of the multilayer body, and the connection pattern is formed of a metal plating film in which the lead-out portion and the lead-out portion of the adjacent conductor pattern are deposited starting from both lead-out portions. In order to make an electrical connection between the conductor patterns through the surface of the laminate, through holes are formed at different positions for each insulating layer, and a conductive paste is formed in the through holes. Rather than a complicated process of forming a via-hole conductor by filling a plurality of times, a connection pattern made of a metal plating film is formed by a simple process of immersing the laminate in a plating solution for electroless plating for a predetermined time. It is possible to selectively form and deposit at predetermined portions to electrically connect the conductor patterns.

  In addition, it is not necessary to set the insulating layer to a predetermined thickness or more in order to hold the conductive paste in the through-hole, and by stacking a large number of thin insulating layers, the distance through which the current flows is set to be long. It is possible to easily realize downsizing and high inductance of the type inductor.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an external perspective view showing a multilayer inductor according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the multilayer inductor of FIG. FIG. 3 is a cross-sectional view showing a conductor pattern of the multilayer inductor of FIG.

  In the figure, a multilayer inductor 10 has input / output terminals 5 and 6 formed on a pair of end faces of a multilayer body 1 formed by laminating a plurality of insulating layers 2. At this time, any of the input / output terminals 5 and 6 may be on the input side or the output side, and the laminate 1 is symmetrical with respect to the input / output terminals 5 and 6 in order to completely eliminate the mounting direction. It is desirable to be.

  In the input / output conductors 5 and 6, for example, a Ni plating layer having a thickness of 2 to 3 μm and an Sn plating layer having a thickness of 4 to 5 μm are sequentially formed on the surface of a Cu plating layer having a thickness of 5 to 10 μm.

  The insulating layer 2 is made of a ferromagnetic material such as Cu—Zn ferrite, Mn—Zn ferrite, Ni—Zn ferrite, Mn—Mg—Zn ferrite, Ni—Zn—Cu ferrite, ceramic dielectric material, or insulator such as alumina. Although an organic insulator material such as polypropylene can be used as the material, a ferromagnetic material is desirable from the viewpoint of increasing the inductance. In addition, in order for the metal plating film deposited from the lead-out portion of the adjacent conductor pattern to grow so as to straddle both lead-out portions, the thickness of the insulating layer 2 is desirably 8 μm or less.

  Inside the laminate 1, a linear conductor pattern 3 is interposed between adjacent insulating layers 2. Further, both ends of the conductor pattern 3 are led out to the adjacent surface of the multilayer body 1, and the lead-out part and the lead-out part of the conductor pattern 3 adjacent to each other are connected by a metal plating film deposited from both lead-out parts. The coil pattern 11 is formed by being electrically connected on the surface of the multilayer body 1 through the patterns 4b to 4d.

  In the multilayer body 1, dielectric bodies 2 with input / output patterns 7 and 8 interposed therebetween are stacked on both sides in the stacking direction of the dielectric body 2 with the conductor pattern 3 interposed therebetween. Input / output terminals 5 and 6 are formed so as to straddle the input / output pattern 8 led out to the surface of the multilayer body 1 from the input / output pattern 8 formed on the end face of the multilayer body 1. The input / output patterns 7 and 8 electrically connect the coil pattern 11 to the input / output terminals 5 and 6, and at least a part of the input / output patterns 7 and 8 is exposed so as to correspond to the lead-out portion of the conductor pattern 3 to be connected. ing. Here, when the input / output terminals 5 and 6 are formed of a plated layer, the input / output pattern 8 formed on the end face of the laminate 1 is formed so that the plated layer is formed on the entire end face of the laminate 1. Although it is necessary to form the entire surface, the input / output pattern 8 derived only on the surface of the stacked body 1 may have a non-formed portion other than the derived portion. As a result, the contact area between the dielectric layers 2-2 sandwiching the input / output pattern 8 derived only on the surface of the laminate 1 is increased, and peeling between these dielectric layers 2-2 can be prevented.

  The input / output pattern 7 is led out to the same surface as the leading portion of the outermost conductor pattern 3 in the stacking direction of the multilayer body 1. Then, starting from the input / output pattern 7, a metal plating film is deposited, and connection patterns 4 a and 4 e that electrically connect the input / output terminals 5 and 6 and the lead-out portion of the conductor pattern 3 are formed.

  The conductor pattern 3 and the input / output patterns 7 and 8 are made of Ag, Cu, Ni, Au, Pt, or a low resistance material of these alloys.

  Similar to the input / output conductors 5 and 6, the connection pattern 4 has, for example, a Ni plating layer having a thickness of 2 to 3 μm and a Sn plating layer having a thickness of 4 to 5 μm on the surface of a Cu plating layer having a thickness of 5 to 10 μm. It is formed sequentially.

  Here, the input / output conductors 5 and 6 may be formed by applying a conductive paste to the surface of the laminate 1 and baking it. In this case, the insulating layer 2 can be formed without interposing the input / output pattern 8.

  As a result, the current is supplied to the input terminal 5, the connection pattern 4a, the conductor pattern 3a, the connection pattern 4b, the conductor pattern 3b, the connection pattern 4c, the conductor pattern 3c, the connection pattern 4d, the conductor pattern 3d, the connection pattern 4e, and the output terminal. In order of 6, the inside of the laminated body 1 flows spirally.

  Hereinafter, a method for manufacturing the multilayer inductor 10 of the present invention will be described. In the figure, each symbol is not distinguished before and after firing.

  First, organic solvent, glass frit, organic binder, etc. suitable for powder of ferromagnetic material such as Cu-Zn ferrite, Mn-Zn ferrite, Ni-Zn ferrite, Mn-Mg-Zn ferrite, Ni-Zn-Cu ferrite, etc. Is added and mixed to produce a slurry-like ceramic slurry, and the obtained ceramic slurry is formed into a ceramic green sheet 2 serving as an insulating layer having a predetermined shape and a predetermined thickness by a conventionally known doctor blade method or the like.

  Next, a conductive paste obtained by adding and mixing an appropriate organic solvent, organic binder, or the like to the conductive powder of Ag, Cu, Ni, Au, Pt, or an alloy thereof on the main surface of the ceramic green sheet 2. The conductive patterns 3a to 3d are formed by applying to a predetermined pattern by conventionally known screen printing or the like. The conductor patterns 3a to 3d may be formed by depositing and transferring a predetermined pattern of plating film.

  Next, a predetermined number of ceramic green sheets 2 on which conductor patterns 3a to 3d are formed are stacked.

  Next, the laminated conductor patterns 3a to 3d and the ceramic green sheet 2 are heated under pressure to obtain a large laminate. Next, the unsintered laminate 1 is obtained by cutting the large laminate with predetermined dimensions.

  Next, the laminated body 1 is obtained by firing the obtained unfired laminated body 1 at a temperature of 1100 ° C. to 1400 ° C., for example. At this time, the input / output pattern 7 and the conductor pattern 3a to 3d lead-out portions are led out on the surface of the multilayer body 1, respectively.

  Next, connection patterns 4a to 4e and input / output terminals 5 and 6 are formed on the pair of end portions of the laminate 1 by electroless plating. Specifically, it is formed by depositing metal on the surface of the multilayer body 1 starting from the lead-out portions of the conductor patterns 3a to 3d and the input / output patterns 7 and 8, and connecting these precipitates to each other. .

  In this way, the multilayer inductor 10 as shown in FIGS.

  Thus, according to the present invention, it is not necessary to use the via-hole conductor 34 to electrically connect the conductor patterns 3, so that the manufacturing method is simple and inexpensive, and the multilayer body 1 is deformed by the deformation of the multilayer body 1. The problem that the mechanical strength and electrical characteristics of the inductor 10 are reduced can be solved.

  Moreover, since the thickness of the insulating layer 2 can be reduced to increase the number of times that the current spirally flows inside the multilayer body 1, the multilayer inductor 10 can be reduced in size and increased in inductance. Furthermore, since the ratio of the area in which the current flows spirally in the multilayer body 1 to the area of the insulating layer 2 can be increased, the size and the inductance of the multilayer inductor 10 can also be reduced.

  Furthermore, since the connection pattern 4 is made of a metal plating film deposited starting from both lead-out portions of the pair of conductor patterns 3, the laminate 1 is simply immersed in a plating solution for electroless plating for a predetermined time. It can be formed by simple processing, and it becomes a simple and inexpensive manufacturing method, and it is selectively deposited on a necessary portion, and unnecessary conduction does not become a problem. In addition, it is preferable to make the thickness of the connection pattern 4 as thin as 10 μm or less so that the suction efficiency is not lowered by the suction nozzle even if the connection pattern 4 is uneven on the surface of the laminate 1.

  And since the laminated body 1 has a rectangular parallelepiped shape, a simple and inexpensive manufacturing method is possible without changing the normal manufacturing method of the multilayer electronic component, and solder or the like is provided on the wiring board. Therefore, stable mounting is possible, and solder can be prevented from adhering to unnecessary portions of the connection pattern on the surface of the laminate 1.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

  FIG. 4 is a cross-sectional view showing a conductor pattern of a multilayer inductor according to another embodiment of the present invention. According to the figure, since the conductor pattern 3 is formed along the four sides of each insulating layer 2 of the laminate 1, the conductor pattern 3 per layer can be made longer, and more effective. In particular, it is possible to achieve downsizing and high inductance.

  FIG. 5 is a cross-sectional view showing a conductor pattern of a multilayer inductor according to still another embodiment of the present invention. According to the figure, the conductor pattern is formed so as to be along the outer periphery of the multilayer body 1 or has a curved shape, whereby the conductor patterns 3a to 3d per each layer can be lengthened. The multilayer inductor 10 can be more effectively reduced in size and increased in inductance.

  FIG. 6 is a cross-sectional view showing a conductor pattern of a multilayer inductor according to still another embodiment of the present invention. According to the figure, since the conductor patterns 3b to 3g are interposed between the connection patterns 4a-4i that are in the same position in the stacking direction but are not electrically connected, the interval between the connection patterns 4a-4i is increased. Since it is not necessary to increase the thickness of the insulating layer 2 in order to increase the size, this also makes it possible to more effectively reduce the size and increase the inductance.

  FIG. 7 is a cross-sectional view showing a conductor pattern of a multilayer inductor according to still another embodiment of the present invention. According to the figure, the conductor pattern 3 is not led out at all on one surface of the multilayer body 1. As a result, it is possible to prevent unnecessary conduction due to adhesion of solder or the like when solder mounted on a wiring board. For example, when solder mounting is performed on the wiring board so that the surface from which the conductor pattern 3 is not led out becomes the mounting surface, the wiring pattern can be disposed below the multilayer body 1 on the wiring board. The range of circuit design choices increases.

  In the present invention, the surface of the laminate 1 except for the input / output terminals 5 and 6 may be covered with an insulating layer. Also by this, unnecessary conduction due to solder or the like adhering to the connection pattern 4 can be prevented, and unevenness due to the connection pattern on the surface of the laminate 1 can be eliminated, so that the adsorption efficiency by the adsorption nozzle is improved. Can be made. At this time, the insulating layer may be made of glass, insulating resin, or the like, but glass is desirable for improving the moisture resistance and reliability of the multilayer inductor 10.

1 is an external perspective view showing a multilayer inductor according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the multilayer inductor of FIG. 1. It is sectional drawing which shows the conductor pattern of the multilayer inductor of FIG. It is sectional drawing which shows the conductor pattern of the multilayer inductor which concerns on other embodiment of this invention. It is sectional drawing which shows the conductor pattern of the multilayer inductor which concerns on further another embodiment of this invention. It is sectional drawing which shows the conductor pattern of the multilayer inductor which concerns on further another embodiment of this invention. It is sectional drawing which shows the conductor pattern of the multilayer inductor which concerns on further another embodiment of this invention. It is sectional drawing which shows the conductor pattern of the conventional multilayer inductor.

Explanation of symbols

10... Multilayer Inductor 1... Laminated Body 2. Insulating Layer 3... Conductor Pattern 4... Connection Pattern 11. ... Input / output terminals 7, 8 ... Input / output patterns

Claims (1)

A multilayer inductor in which a linear conductor pattern is interposed between adjacent insulating layers in a laminate formed by laminating a plurality of insulating layers, and a coil pattern is formed by electrically connecting these conductor patterns. In
Both ends of the conductor pattern are led out to the surface of the multilayer body, and the lead-out part of the conductor pattern adjacent to the lead-out part is connected via a connection pattern made of a metal plating film precipitated from both lead-out parts. A multilayer inductor characterized by being electrically connected on the surface of the multilayer body.

Images