Patent ID: 12255008

DETAILED DESCRIPTION

Hereinafter, an inductor component according to an aspect of the present disclosure is described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic drawings, and the actual dimensions and ratios may not be reflected in some cases.

First Embodiment

Structure

FIG.1is a perspective view illustrating a first embodiment of an inductor component.FIG.2is an exploded perspective view of the inductor component.FIG.3Ais a sectional view ofFIG.1taken along line X-X.FIG.4is a sectional view illustrating a state in which the inductor component is mounted on a mounting substrate. As illustrated inFIG.1,FIG.2, andFIG.3A, an inductor component1includes an element body10, a coil20in a spiral shape provided inside the element body10, and a first outer electrode30and a second outer electrode40which are provided to the element body10and electrically connected to the coil20. InFIG.3A, illustration of the coil20is omitted.

As illustrated inFIG.4, the inductor component1(first outer electrode30and second outer electrode40) is electrically connected, with solder52, to a wire51aof a mounting substrate51. The inductor component1is used as, for example, an impedance matching coil (matching coil) in a high frequency circuit, and is used in an electronic device such as a personal computer, a DVD player, a digital camera, a TV, a cellular phone, a car electronics, and a medical/industrial machine. However, the application of the inductor component1is not limited to the above and includes, for example, a tuning circuit, a filter circuit, a rectifying and smoothing circuit, or the like.

The element body10is formed by laminating a plurality of insulating layers11in a lamination direction A. Each insulating layer11is made of, for example, a material containing borosilicate glass as a main component, or a material such as ferrite or resin. Note that, in the element body10, the interface between the plurality of insulating layers11may be not clear due to firing or the like in some cases. The element body10is formed as a substantially rectangular parallelepiped. The surface of the element body10has a first end surface15and a second end surface16opposite to each other in the longitudinal direction of the rectangular parallelepiped, and has a bottom surface17intersecting with the first end surface15and the second end surface16and corresponding to one of the two surfaces opposite to each other in the height direction of the rectangular parallelepiped. The first end surface15and the second end surface16are opposite to each other in a direction orthogonal to the lamination direction A of the insulating layers11. The first end surface15is a surface on which part of the first outer electrode30is provided, and the second end surface16is a surface on which part of the second outer electrode40is provided. The bottom surface17is a surface that faces the mounting substrate51at the time of mounting. The bottom surface17is a surface at which both of the other part of the first outer electrode30and the other part of the second outer electrode40are provided.

The first outer electrode30has an L-shape extending across the first end surface15and the bottom surface17. The second outer electrode40has an L-shape extending across the second end surface16and the bottom surface17. The first outer electrode30includes a plurality of outer electrode conductor layers33embedded in the element body10. The second outer electrode40includes a plurality of outer electrode conductor layers43embedded in the element body10.

Each outer electrode conductor layer33included in the first outer electrode30has an L-shape including a portion extending along the first end surface15and the bottom surface17, and each outer electrode conductor layer43included in the second outer electrode40has an L-shape including a portion extending along the second end surface16and the bottom surface17. With this, since the first outer electrode30and the second outer electrode40are able to be embedded in the element body10, it is possible to reduce the size of the inductor component compared with a configuration in which the outer electrode is externally attached to the element body10. Further, since the coil20, the first outer electrode30, and the second outer electrode40are able to be formed in the same process, variations in the positional relationship among the coil20, the first outer electrode30, and the second outer electrode40may be reduced, and it is thus possible to reduce variations in the electrical characteristics of the inductor component1.

The coil20is formed of, for example, a conductive material similar to the outer electrode conductor layer33of the first outer electrode30and the outer electrode conductor layer43of the second outer electrode40. The coil20is spirally wound along the lamination direction A of the insulating layers11. That is, the axis of the coil20is parallel to the bottom surface17parallel to the lamination direction A, and the coil20has a lateral winding structure when mounted on the mounting substrate51. The axis of the coil20means the central axis of the spiral shape of the coil20. One end of the coil20is in contact with the first outer electrode30, and the other end of the coil20is in contact with the second outer electrode40. Note that, in the present embodiment, the coil20and the first and second outer electrodes30and40are integrated and there is no clear boundary therebetween. However, not being limited to this, a boundary may exist when the coil and the outer electrodes are formed by different kinds of materials or different types of processes.

The coil20includes a plurality of coil conductor layers21wound on the insulating layers11. Thus, since the coil20is formed of the coil conductor layers21that may be finely processed, it is possible to achieve reduction in size and reduction in height of the inductor component1. The coil conductor layers21adjacent to each other in the lamination direction A are connected to each other through a via conductor extending through the insulating layers11in the thickness direction. That is, one end of the one coil conductor layer21is connected to the other end of other coil conductor layer21. Thus, the plurality of coil conductor layers21constitute a spiral while being connected to each other. Specifically, the coil20has a configuration in which the plurality of coil conductor layers21each of which has the number of turns less than one are connected to each other and are laminated, and the coil20has a helical shape. With this, the parasitic capacitance generated in the coil conductor layer21and the parasitic capacitance generated between the coil conductor layers21may be reduced, and the Q factor of the inductor component1may be improved. Note that the number of turns of the coil conductor layer21may be one or more.

As illustrated inFIG.3A, the first outer electrode30includes an underlying layer31and a coating film32. The underlying layer31corresponds to the outer electrode conductor layers33inFIG.2, and illustration of the coating film32is omitted inFIG.2.

The underlying layer31is embedded in the element body10such that part of the underlying layer31protrudes from the surface of the element body10. That is, part of the underlying layer31(protruding portion31a) protrudes from the bottom surface17of the element body10.

The underlying layer31does not protrude from the first end surface15of the element body10and is exposed. That is, one surface31bof the underlying layer31is positioned on the same plane as the first end surface15of the element body10. In other words, the underlying layer31does not protrude from the surface other than the bottom surface17of the element body10. The exposure of the underlying layer31at the element body10means that the underlying layer31has a portion that is not covered by the element body10, and the portion may be exposed to the outside of the inductor component1or may be exposed to another member.

A thickness T1of the underlying layer31at the bottom surface17is larger than a thickness T2of the underlying layer31at the first end surface15. The thickness T1of the underlying layer31at the bottom surface17is, in the cross-section ofFIG.3A, the thickness of the portion of the underlying layer31positioned at the bottom surface17in a direction orthogonal to the bottom surface17. Similarly, the thickness T2of the underlying layer31at the first end surface15is, in the cross-section ofFIG.3A, the thickness of the portion of the underlying layer31positioned at the first end surface15in a direction orthogonal to the first end surface15. As illustrated in the cross-section ofFIG.3B, the thickness T1of the underlying layer31at the bottom surface17may be equal to the thickness T2of the underlying layer31at the first end surface15. Here, the term “equal” does not mean that it is absolutely the same, and includes, for example, a manufacturing variation and the like.

The coating film32covers the portion of the underlying layer31exposed at the element body10. For example, the coating film32covers all of the protruding portion31aof the underlying layer31and the one surface31bof the underlying layer31. The protrusion amount of the first outer electrode30from the first end surface15is smaller than the protrusion amount of the first outer electrode30from the bottom surface17.

The underlying layer31is formed by, for example, baking a conductive paste including a conductive material such as Ag, Cu, Au, or an alloy containing these as a main component and a glass component. The coating film32is formed on the underlying layer31by a plating process, for example. The coating film32is formed of, for example, two layers of a Ni film and a Sn film. However, the coating film is not limited to including two layers, and may be a single layer, or include three or more layers. The Ni film covers the underlying layer31and prevents dissolution of metallization of the underlying layer31. The Sn film covers the Ni film, and improves the solder wettability of the first outer electrode30. Note that the coating film32may be formed by applying a conductive resin paste, for example, or may be formed by sputtering process instead of plating process.

Similarly to the first outer electrode30, the second outer electrode40includes an underlying layer41and a coating film42. The underlying layer41is embedded in the element body10such that part of the underlying layer41protrudes from the surface of the element body10. That is, part of the underlying layer41(protruding portion41a) protrudes from the bottom surface17of the element body10. Further, one surface41bof the underlying layer41is exposed at the second end surface16of the element body10. The coating film42covers the portion of the underlying layer41exposed at the element body10. The underlying layer41and the coating film42are formed of the same material as those of the first outer electrode30.

According to the inductor component1, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the surface of the element body10and the coating films32and42cover the underlying layers31and41, the area in which the coating films32and42are in contact with the underlying layers31and41may be increased, and the fixing force of the coating films32and42to the underlying layers31and41is improved.

As illustrated inFIG.4, when the inductor component1is mounted on the mounting substrate51, that is, when an electronic component50is manufactured by connecting the inductor component1to the wire51aof the mounting substrate51with the solder52, since the surface area of the coating films32and42increases, the contact area with the solder52may be increased and the fixing force of the inductor component1to the mounting substrate51is improved.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, the surface area of the coating films32and42at the bottom surface17of the element body10may be increased. Thus, when the inductor component1is mounted on the mounting substrate51, the surface area of the coating films32and42facing the mounting substrate51may be increased and the contact area with the solder52may further be increased, and the fixing force of the inductor component1to the mounting substrate51is thus further improved.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, it is possible to adopt a configuration in which the first outer electrode30and the second outer electrode40are shifted toward the bottom surface17of the element body10. With this, the inner diameter of the coil20may be widely formed close to the bottom surface17of the element body10, and it is possible to improve the efficiency of acquiring the L value and the Q factor.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, it is possible to increase the volume of the first outer electrode30and the second outer electrode40protruding from the bottom surface17of the element body10. With this, in a case where the inductor component1is mounted on the mounting substrate51, when the inductor component1receives an impact from the outside, the first outer electrode30and the second outer electrode40may disperse the impact, and it is thus possible to improve the impact resistance. Further, since the bottom surface17and the underlying layers31and41(interface between the underlying layers31and41and the coating films32and42) are not flush with each other, it is possible to suppress the peeling off of the coating films32and42from the interface.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, the bottom surface of the underlying layers31and41may easily be polished by an abrasive before the coating films32and42are formed on the underlying layers31and41. This makes it possible to easily perform the deburring of the underlying layers31and41. Further, since the deburring of the underlying layers31and41are reliably performed, it is possible to improve the uniformity of the plating film thickness of the coating films32and42. In a case where the underlying layer does not protrude from the bottom surface of the element body, there is a risk that the abrasive is in contact with the bottom surface of the element body and the bottom surface of the underlying layer may not be polished.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, the underlying layers31and41easily contact with the medium in the barrel plating (plating process), and the coating films32and42may be easily formed by the plating process.

Further, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the bottom surface17of the element body10, a distance L between the bottom surface17of the element body10and the mounting surface of the mounting substrate51may be made longer. With this, when the inductor component1is resin-sealed, the resin material easily enters the space between the bottom surface17of the element body10and the mounting surface of the mounting substrate51. As described above, the easiness of resin filling is improved, and the reliability is improved. Further, as described above, since the distance L between the bottom surface17of the element body10and the mounting surface of the mounting substrate51may be made longer, it is possible to suppress the blocking of the magnetic flux of the coil20by the mounting substrate51, and the characteristics of the inductor component1are improved.

Further, since the underlying layers31and41do not protrude from the surface other than the bottom surface17of the element body10, it is possible to achieve both the reduction in size and the improvement of the fixing force.

Further, since the underlying layer31does not protrude from the first end surface15of the element body10and is exposed, it is possible to achieve both the reduction in size and the improvement of the fixing force. Note that since the underlying layer41does not protrude from the second end surface16of the element body10and is exposed, the same effect is obtained.

Further, since the protrusion amount of the first outer electrode30from the first end surface15is smaller than the protrusion amount of the first outer electrode30from the bottom surface17, it is possible to achieve both the reduction in size and the improvement of the fixing force. Since the protrusion amount of the second outer electrode40from the second end surface16is smaller than the protrusion amount of the second outer electrode40from the bottom surface17, the same effect is obtained.

Further, since the thickness T1of the underlying layer31at the bottom surface17is larger than the thickness T2of the underlying layer31at the first end surface15, the volume of the first outer electrode30and the second outer electrode40may be increased without increasing the length of the first outer electrode30and the second outer electrode40in the longitudinal direction, and thus it is possible to achieve both the reduction in size and the improvement of impact resistance. Further, the thickness T1of the underlying layer31at the bottom surface17may be the same as the thickness T2of the underlying layer31at the first end surface15, and in this case, the inner diameter of the coil20may widely be formed and it is possible to improve the efficiency of acquiring the L value and the Q factor.

Further, the electronic component50includes the inductor component1and the mounting substrate51on which the inductor component1is mounted. According to the electronic component50, since the surface area of the coating films32and42of the inductor component1increases, when the inductor component1is mounted, with the solder52, on the mounting substrate51, the contact area between the solder52and the coating films32and42may be increased, and the fixing force of the inductor component1to the mounting substrate51is improved.

Note that the bottom surface (coating films32and42) of the first outer electrode30and the second outer electrode40may have a flat surface, or may have unevenness. When the bottom surface of the first outer electrode30and the second outer electrode40have unevenness, the surface area of the bottom surface of the first outer electrode30and the second outer electrode40(coating films32and42) increases. In addition, when the bottom surface of the first outer electrode30and the second outer electrode40has a dent, the solder gathers therein and the posture becomes stable.

Further, when the bottom surface17of the element body10is viewed, the bottom surface of the first outer electrode30and the second outer electrode40has a rectangular shape, but may have a T-shape, or the edge of the bottom surface of the first outer electrode30and the second outer electrode40may have a comb-tooth shape having continuous unevenness.

Manufacturing Method

A manufacturing method for the inductor component1is described with reference toFIG.2.

First, a first insulating layer (corresponding to an insulating layer11inFIG.2) is formed. Specifically, an insulating paste such as glass is applied to a substrate such as a carrier film, and the entire surface of the insulating paste is exposed to ultraviolet rays. The insulating layer11serving as a marker layer may be provided as a lowermost layer or a uppermost layer of the element body10, and the marker layer preferably has a color different from the color of the insulating layers11other than the marker layer so as to detect such as the rollover of the inductor component1at the time of mounting.

Next, the coil conductor layer21is formed on the first insulating layer. Specifically, a photosensitive conductive paste is applied to the first insulating layer by printing, and the coil conductor layer21is formed by a photolithography method. The outer electrode conductor layers33and43are formed at the same time. The number of layers, the thickness, and the number of turns of the coil conductor layer21are set to a desired value according to the L value to be obtained.

Subsequently, a second insulating layer (corresponding to an insulating layer11inFIG.2) is formed on the coil conductor layer21. Specifically, the second insulating layer having a via hole and an outer electrode groove is formed on the coil conductor layer21by the photolithography method or the like. After that, by forming the coil conductor layer21and the outer electrode conductor layers33and43on the second insulating layer again, the via hole and the outer electrode groove are filled with the conductive paste. The coil conductor layers21adjacent to each other in the lamination direction A are connected, and the outer electrode conductor layers33adjacent to each other in the lamination direction A are connected, and the outer electrode conductor layers43adjacent to each other in the lamination direction A are connected. Note that, there may be an insulating layer11where the coil conductor layer21is not provided depending on the setting of the number of layers of the coil conductor layer21. In that case, the via hole is not formed and the outer electrode groove alone is formed in the shape following the shape of the outer electrode.

Further, extended conductor layers are connected to at least the lowermost layer and the uppermost layer of the coil conductor layer21, and are connected to the outer electrode conductor layers33and43which are opposite to each other, respectively. It is preferable that the shape of the coil20have a 180° rotational symmetricity so as not to be affected by the directivity of a product.

The above-described steps are repeated to laminate the plurality of insulating layers11, the plurality of coil conductor layers21, and the plurality of outer electrode conductor layers33and43. Subsequently, the multilayer body is cut with a dicing machine, guillotine shearing machine, or the like, and is divided into individual pieces. The divided multilayer body is fired to be formed in a desired size. Here, by making the shrinkage ratio of the outer electrode conductor layers33and43smaller than the shrinkage ratio of the insulating layer11, the shrinkage ratio of the element body10becomes larger than the shrinkage ratio of the outer electrode conductor layers33and43by firing, and control is performed such that part of the outer electrode conductor layers33and43(underlying layers31and41) protrudes from the bottom surface17of the element body10.

Subsequently, the inductor component1is manufactured such that Ni, Cu, Sn, or the like is plated on the exposed portion of the outer electrode conductor layers33and43at the element body10, and the coating films32and42are formed. Note that although the photolithography method is described in the above, a lamination method, a semi-additive method, or the like may be adopted and the methods are not limited.

Second Embodiment

FIG.5is a bottom view illustrating a second embodiment of the inductor component. The second embodiment is different from the first embodiment in the configuration of the outer electrodes. This different configuration is described below. The other configurations are the same as those in the first embodiment, and the same reference numerals as in the first embodiment are given and description thereof is omitted.

As illustrated inFIG.5, as for an inductor component1A of the second embodiment, in a first outer electrode30A, when viewed from the bottom surface17of the element body10, the interface between the underlying layer31(protruding portion31a) and the element body10is covered by the coating film32. That is, in the first outer electrode30A, the outer peripheral edge of the coating film32is positioned outside the outer peripheral edge of the underlying layer31(protruding portion31a) when viewed from the bottom surface17of the element body10.

Similarly, in a second outer electrode40A, when viewed from the bottom surface17of the element body10, the interface between the underlying layer41(protruding portion41a) and the element body10is covered by the coating film42. That is, in the second outer electrode40A, the outer peripheral edge of the coating film42is positioned outside the outer peripheral edge of the underlying layer41(protruding portion41a) when viewed from the bottom surface17of the element body10.

According to the inductor component1A, since the interface between the underlying layers31and41and the element body10is covered by the coating films32and42, the surface area of the coating films32and42may be increased, and the strength against bending of the element body10may be improved. In addition, it is possible to prevent moisture from entering between the underlying layers31and41and the element body10from the outside of the element body10. Further, the contact area with the solder52may be further increased and the fixing force of the inductor component1A to the mounting substrate51may be further improved.

Third Embodiment

FIG.6is a sectional view illustrating a third embodiment of the inductor component. The third embodiment is different from the first embodiment in the configuration of the outer electrodes. This different configuration is described below. The other configurations are the same as those in the first embodiment, and the same reference numerals as in the first embodiment are given and description thereof is omitted.

As illustrated inFIG.6, as for an inductor component1B of the third embodiment, in a first outer electrode30B, part of the underlying layer31(protruding portion31aof underlying layer31) protruding from the bottom surface17of the element body10includes an overhanging portion31cthat overhangs on the bottom surface17of the element body10and covers the bottom surface17of the element body10. The overhanging portion31cprotrudes toward a second outer electrode40B. The overhanging portion31cmay be provided to the underlying layer31in the entire length along the axial direction of the coil20(along the direction from front to back of the paper), or may be provided to the underlying layer31in part of the entire length. Similarly, in the second outer electrode40B, the protruding portion41aof the underlying layer41includes an overhanging portion41cthat overhangs on the bottom surface17of the element body10and covers the bottom surface17of the element body10.

According to the inductor component1B, since the protruding portions31aand41aof the underlying layers31and41include the overhanging portions31cand41c, the volume of the portion of the outer electrodes30B and40B protruding from the element body10may be increased, and the strength of the inductor component1B against bending may further be improved.

Fourth Embodiment

FIG.7is an exploded perspective view illustrating a fourth embodiment of the inductor component. The fourth embodiment is different from the first embodiment in the configuration of the element body, the outer electrode, and the coil. This different configuration is described below. The other configurations are the same as those in the first embodiment, and the same reference numerals as in the first embodiment are given and description thereof is omitted.

As illustrated inFIG.7, in an inductor component1C of the fourth embodiment, an element body10C includes the plurality of insulating layers11laminated in the lamination direction A, and the uppermost insulating layer11inFIG.7constitutes the bottom surface17of the element body10C. The coil conductor layer21constituting a coil20C, the outer electrode conductor layer33constituting a first outer electrode30C, and the outer electrode conductor layer43constituting a second outer electrode40C are provided on a predetermined insulating layer11.

With this, the axis of the coil20C is orthogonal to the bottom surface17of the element body10C, and the coil20C has a longitudinal winding structure. The protruding portion31aof the underlying layer31of the first outer electrode30C is formed on the uppermost insulating layer11, and protrudes from the bottom surface17of the element body10C. The protruding portion41aof the underlying layer41of the second outer electrode40C is formed on the uppermost insulating layer11, and protrudes from the bottom surface17of the element body10C.

At this time, as a method for forming the protruding portions31aand41a, a region where the protruding portions31aand41aare not formed may be masked with a sheet or the like. Alternatively, a seed layer is formed in a region where the protruding portions31aand41aare to be formed, and the protruding portions31aand41amay be formed by plating deposition. The methods of forming the protruding portions31aand41aare not limited to the above, and other methods may be employed.

According to the inductor component1C, as in the first embodiment, since part of the underlying layers31and41(protruding portions31aand41a) protrudes from the surface of the element body10and the coating films32and42cover the protruding underlying layers31and41, the area in which the coating films32and42are in contact with the underlying layers31and41may be increased, and the fixing force of the coating films32and42to the underlying layers31and41is improved.

It should be noted that the present disclosure is not limited to the above-described embodiments, and design changes may be made without departing from the gist of the present disclosure. For example, the features of the first to fourth embodiments may be variously combined with each other.

In the embodiments, the underlying layer of the outer electrode protrudes from the bottom surface of the element body. However, the underlying layer may protrude from the end surface of the element body instead of the bottom surface of the element body, or may protrude from the bottom surface and the end surface of the element body.

In the embodiments, when viewed from the bottom surface of the element body, the outer peripheral edge of the coating film is positioned on the outer peripheral edge of the underlying layer or outside the outer peripheral edge of the underlying layer. However, at least part of the outer peripheral edge of the coating film may be positioned inside the outer peripheral edge of the underlying layer, thereby ensuring a sufficient distance between the adjacent outer electrodes.

While preferred embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.