Stacked inductor

Abstract

The present invention provides a laminated inductor which has high mechanical strength and is less likely to be deformed or warped. A component body (2) has an end face layer (9, 10) which has high rigidity and a low strength layer (11) which has low rigidity. The end face layer has a first end face layer (9) which constitutes a first end face (3) of the component body (2) and a second end face layer (10) which constitutes a second end face (4). Furthermore, the first end face layer (9) has a thickness which is thicker than a thickness of the second end face layer (10). With a total thickness of the first end face layer (9) and the second end face layer (10) being constant, if the thickness of the first end face layer (9) is made thicker than the thickness of the second end face layer (10), the thickness of the first end face layer (9) itself can be made thicker than in a case where the thicknesses of the first end face layer (9) and the second end face layer (10) are equal to each other. Furthermore, the first end face layer (9) which is thus made thicker can impart high mechanical strength to the component body (2).

Description

[0001] This application is a divisional application of the invention patent application with patent application number 202010817249.7 (application date: August 14, 2020, invention title: "Laminated Inductor"). Technical Field

[0002] The present invention relates to a multilayer inductor having a structure in which coil conductors are arranged inside a component body made of a multilayer structure of non-conductive material, and particularly to improvements for achieving increased strength of the multilayer inductor. Background Technology

[0003] As a technology related to this invention, for example, there is the technology described in Japanese Patent No. 4941585 (Patent Document 1). In Patent Document 1, as a specific embodiment, a multilayer chip capacitor is described instead of a multilayer inductor. However, in this chip capacitor, at both ends of the stacking direction of the cuboid-shaped component body having a multilayer structure, an identification layer with a different color from the other ceramic layers is provided. The identification layer is used to visually determine the arrangement direction of the conductors disposed inside the component body.

[0004] Patent Document 1 describes the following: In order to make the color of the identification layer different from the colors of other ceramic layers, for example, the average particle size of the ceramic particles constituting each layer is different from each other, or the additives contained in each layer are different from each other, or the composition ratio of the ceramic materials constituting each layer is different from each other.

[0005] Patent Document 1: Japanese Patent No. 4941585 Specification

[0006] In Patent Document 1, regarding the identification layer, no function other than the function of visually determining the arrangement direction of conductors disposed inside the main body of the component is described.

[0007] On the other hand, when developing the multilayer inductor, the inventors focused on embodiments where the composition of the identification layer differs from that of the other ceramic layers, and on the possibility of enabling the identification layer to possess functions beyond those described above, such as improving the mechanical strength of the multilayer inductor. That is, since the identification layer is disposed at both ends in the stacking direction of the component body, if the mechanical strength of the identification layer is high, the identification layer can contribute to improving the mechanical strength of the multilayer inductor.

[0008] The mechanical strength of multilayer inductors becomes a problem, for example during reflow soldering or flexural testing. The lower the mechanical strength, the greater the deformation or warping of the multilayer inductor, and sometimes cracks may appear in the multilayer inductor. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a structure of a stacked inductor that, with regard to the function of the aforementioned identification layer, can be expected to further improve mechanical strength.

[0010] This invention relates to a multilayer inductor comprising: a component body made of a non-conductive material, having a cuboid or substantially cuboid shape with a multilayer structure, and having a first end face and a second end face facing each other in the multilayer direction, a first side face and a second side face facing each other connecting the first end face and the second end face, and a top surface and a bottom surface facing each other connecting the first end face and the second end face and the first side face and the second side face, respectively; a coil conductor having a first end face and a second end face facing each other exposed on the outer surface of the component body, and having a surrounding portion disposed inside the component body and extending parallel to the first end face and the second end face; a first terminal electrode configured to include the first end face of the coil conductor; and a second terminal electrode configured to include the second end face of the coil conductor.

[0011] To solve the above-mentioned technical problems, the present invention is characterized in that the main body of the component has a first end face layer providing a first end face, a second end face layer providing a second end face, and a low-strength layer with a lower rigidity than the first end face layer and the second end face layer, wherein the thickness of the first end face layer is greater than the thickness of the second end face layer.

[0012] Furthermore, there are cases where the thickness of the first end-face layer is greater than the thickness of the second end-face layer, or where the thickness of the second end-face layer is zero. In this case, the first end-face is provided by the end-face layer, and the second end-face is provided by the low-strength layer.

[0013] In this invention, the end-face layer helps to improve the mechanical strength of the multilayer inductor. Moreover, the thicker the end-face layer, the greater the mechanical strength. However, simply increasing the thickness of the end-face layer leads to a larger multilayer inductor, which is therefore not preferred.

[0014] Therefore, in this invention, instead of simply thickening both the first end face layer providing the first end face and the second end face layer providing the second end face in the component body, only the first end face layer of one side is thickened, while the second end face layer of the other side is thinned by an amount corresponding to the thickening of the first end face layer, or, depending on the situation, it is eliminated. As a result, the large size of the stacked inductor can be avoided.

[0015] Furthermore, while maintaining a constant combined thickness of the first and second end-face layers, making the first end-face layer thicker than the second end-face layer allows for a greater thickness of the first end-face layer itself compared to when the thicknesses of the first and second end-face layers are equal. This increased thickness of the first end-face layer imparts higher mechanical strength to the component body. Therefore, deformation or warping in multilayer inductors can be reduced, for example, during reflow soldering or flexural testing, thus reducing the likelihood of cracking in multilayer inductors. Attached Figure Description

[0016] Figure 1 This is a perspective view showing the appearance of the stacked inductor 1 according to the first embodiment of the present invention.

[0017] Figure 2 It is Figure 1 The exploded perspective view of the multilayer inductor 1 shown is omitted, as the coating formed on the terminal electrodes 27 and 28 is not illustrated.

[0018] Figure 3 It is represented from the first side in five directions. Figure 1 The side view of the stacked inductor 1 shown.

[0019] Figure 4 This is a side view of the stacked inductor 1a according to the second embodiment of the present invention, shown from the first side 5 direction.

[0020] Figure 5 This is a side view of the stacked inductor 1b according to the third embodiment of the present invention, shown from the first side direction 5.

[0021] Explanation of reference numerals in the attached figures

[0022] 1, 1a, 1b…Layered inductor; 2…Component body; 3…First end face; 4…Second end face; 5…First side face; 6…Second side face; 7…Top surface; 8…Bottom surface; 9…First end face layer; 10…Second end face layer; 11…Low strength layer; 11-1…First low strength outer layer; 11-2 to 11-7…Low strength intermediate layer; 11-8, 11-9…First low strength outer layer; 20…Coil conductor; 21…First end; 22…Second end; 23…Wrapping portion; 24…Through-hole conductor; 27…First terminal electrode; 28…Second terminal electrode; 29, 30…Coating; 31, 32…End edge; 33, 34…Interface. Detailed Implementation

[0023] Reference Figures 1-3 The first embodiment of the multilayer inductor 1 of the present invention will be described.

[0024] The multilayer inductor 1 has a main body 2 made of a non-conductive material. For example... Figure 2 As shown, the main body 2 of the component has a layered structure. Here, as a non-conductive material, for example, a material in which ceramic fillers such as ferrite, metallic magnetic fillers, or non-magnetic fillers such as silica are added to a glass such as borosilicate glass can be used. Resin can also be used instead of glass.

[0025] The main body of component 2 has a cuboid shape or a roughly cuboid shape. Here, a roughly cuboid shape means that the main body of component 2 may, for example, have rounded edges and corners, beveled corners, or that at least one of the six faces of the cuboid may not be a rectangle in the strict sense.

[0026] like Figure 1 As shown, the main body 2 of the component has a first end face 3 and a second end face 4 located at the ends in the stacking direction, i.e. the beginning and end in the stacking direction, and opposite to each other; a first side face 5 and a second side face 6 connecting the first end face 3 and the second end face 4 and opposite to each other; and a top face 7 and a bottom face 8 connecting the first end face 3 and the second end face 4 and the first side face 5 and the second side face 6 respectively and opposite to each other.

[0027] like Figure 2 As shown, the main body 2 of the component has a laminated structure consisting of multiple layers, namely end face layers 9 and 10 and a low-strength layer 11 with lower rigidity than the end face layers 9 and 10. Here, the end face layers 9 and 10 are classified as a first end face layer 9 providing the first end face 3 and a second end face layer 10 providing the second end face 4. The multiple low-strength layers 11 are located between the first end face layer 9 and the second end face layer 10.

[0028] To achieve higher rigidity in end-face layers 9 and 10 than in low-strength layer 11, for example, when both contain glass and are composed of a combination of filler and resin, the filler content in end-face layers 9 and 10 is higher than that in low-strength layer 11. Furthermore, when end-face layers 9 and 10 and low-strength layer 11 are composed, for example, of a combination of filler and resin, the filler content in end-face layers 9 and 10 is higher than that in low-strength layer 11. Additionally, to improve mechanical strength, it is also possible to construct the entire area of ​​the component body 2 with a layer comparable to the more rigid end-face layers. However, as will be described later, since the coil conductor 20 is disposed in low-strength layer 11, a composition that prioritizes electrical and magnetic properties compared to end-face layers 9 and 10 is adopted in low-strength layer 11.

[0029] A coil conductor 20 extending in a spiral shape is disposed in the component body 2. The coil conductor 20 has a first end 21 and a second end 22 opposite to each other, and has a plurality of surrounding portions 23 extending along any interface between a plurality of low-strength layers 11 inside the component body 2 and forming part of a ring-shaped track, and a plurality of through-hole conductors 24 penetrating any one of the low-strength layers 11 in the thickness direction to connect the first end 21 and the second end 22. The surrounding portions 23 extend parallel to the first end face 3 and the second end face 4.

[0030] In the coil conductor 20, the aforementioned winding portions 23 and through-hole conductors 24 are alternately connected to form a spiral extension. At each end and specific portion of the plurality of winding portions 23, a large through-hole pad 25 for connection with the through-hole conductor 24 is provided. Figure 2 In the diagram, the through-hole conductor 24 is represented by a single-dot dash to indicate its electrical connection state.

[0031] The first end 21 and the second end 22 of the coil conductor 20 should serve as terminals of the coil conductor 20, and are therefore configured to be embedded inside the component body 2, and exposed on the outer surface of the component body 2. More specifically, as... Figure 2 As shown, the first end 21 and the second end 22 are each L-shaped and are exposed at intervals on the bottom surface 8 of the main body 2, on the first side 5 and the second side 6, respectively. In addition, the first end 21 is connected to the portion exposed on the bottom surface 8 and is exposed on the first side 5, and the second end 22 is connected to the portion exposed on the bottom surface 8 and is exposed on the second side 6.

[0032] As described above, the first end 21 and the second end 22 of the coil conductor 20 are exposed across two adjacent surfaces of the component body 2, respectively, and each exposed portion of the first end 21 and the second end 22 constitutes a first terminal electrode 27 and a second terminal electrode 28. That is, the first terminal electrode 27 is configured to extend across a portion of the first side surface 5 and the bottom surface 8, and the second terminal electrode 28 is configured to extend across a portion of the second side surface 6 and the bottom surface 8. In this way, by providing terminal electrodes 27 and 28, a fillet weld of appropriate shape can be formed when the multilayer inductor 1 is mounted on the mounting substrate, thus achieving a highly reliable mounting state in both electrical connection and mechanical bonding.

[0033] The first terminal electrode 27 may also have a first coating 29 provided in a manner that covers the exposed portion of the first end 21. The second terminal electrode 28 may also have a second coating 30 provided in a manner that covers the exposed portion of the second end 22. The coatings 29 and 30 can, for example, improve the solder wettability of the first end 21 and the second end 22 of the coil conductor 20, which contains silver as a conductive component, and prevent solder corrosion.

[0034] Furthermore, coatings 29 and 30 can effectively form on the desired locations by using the exposed portions of the first end 21 and the second end 22 as a substrate for electroplating. Coatings 29 and 30 are respectively composed, for example, of a nickel plating layer on a substrate and a tin plating layer thereon. According to this structure, coatings 29 and 30 can advantageously perform the aforementioned functions of improving solder wettability and preventing solder corrosion. Furthermore, a copper plating layer can be formed instead of a nickel plating layer, or a copper plating layer can be formed between the nickel plating layer and the tin plating layer.

[0035] As described above, the main body 2 of the component has a laminated structure, but the interfaces between the multiple layers that realize the laminated structure are almost completely eliminated in the actual product due to the firing or curing process. However, for ease of explanation, it is assumed that a structure with a laminated structure exists, and for each of the end face layers 9 and 10 and each low-strength layer 11, reference is mainly made to... Figure 2 The structure associated with each layer is described.

[0036] Furthermore, in the following description, when it is necessary to describe a specific layer taken from the plurality of low-strength layers 11, reference numerals such as "11-1", "11-2", ... are used to indicate the branch number of "11". Additionally, the same reference numerals are used for each of the plurality of surrounding portions 23, the plurality of through-hole conductors 24, and the plurality of through-hole pads 25 as in the case of the low-strength layers 11 described above.

[0037] exist Figure 2 The diagram illustrates a first end face layer 9, a second end face layer 10, and nine low-strength layers 11-1, 11-2, ..., 11-9. The low-strength layers 11-1, 11-2, ..., 11-9 are stacked in this order from the first end face 3 side toward the second end face 4 side.

[0038] If we consider the respective thicknesses of the first end face layer 9 and the second end face layer 10 located at the very ends, the thickness of the first end face layer 9 is greater than the thickness of the second end face layer 10. High mechanical strength can be imparted by making only one of the first end face layer 9 and the second end face layer 10 thicker, rather than both, for the following reasons.

[0039] Under the same applied external force, the smaller the displacement (warping, deflection), the higher the mechanical strength. Increasing the thickness of end-face layers 9 and 10 decreases the displacement and increases the mechanical strength. The displacement of end-face layers 9 and 10 is determined by the maximum value of their respective thicknesses. Therefore, with a constant total thickness of the two end-face layers 9 and 10, a thicker end-face layer (either 9 or 10) results in greater mechanical strength compared to when the thicknesses of the two end-face layers 9 and 10 are equal.

[0040] Furthermore, thickening both end layers 9 and 10 would lead to an overall increase in product size. To avoid this increase, the internal coil conductors need to be miniaturized, which would have a greater impact on standards and characteristics.

[0041] Preferably, the thickness of the first end face layer 9 is at least 3 μm thicker than the thickness of the second end face layer 10. The current printing thickness deviation is approximately 2.5 μm (3σ), and a value exceeding this of 3 μm is considered a lower limit that represents a significant difference compared to the case where the printing thickness deviation is at its maximum. Furthermore, if the thickness difference between the first end face layer 9 and the second end face layer 10 is 3 μm or more, the aforementioned displacement reduction effect can be reliably achieved.

[0042] Thus, according to this embodiment, the increased mechanical strength resulting from the increased thickness of the first end face layer 9 can be achieved. On the other hand, by thinning the thickness of the second end face layer 10, the large size of the stacked inductor 1 can be avoided.

[0043] Furthermore, when end face layers 9 and 10 are formed by printing, the thickness of each end face layer 9 and 10 can be adjusted by changing the coating thickness during printing. Alternatively, the thickness of each end face layer 9 and 10 can be adjusted by changing the number of layers per unit thickness. Furthermore, the thickness of each end face layer 9 and 10 can also be adjusted by reducing the thickness during cutting in subsequent processes.

[0044] Preferably, the first end face layer 9 and the second end face layer 10 are given a different color from the low-strength layer 11, for example, by adding pigments such as cobalt. Thus, the end face layers 9 and 10 and the low-strength layer 11 have an appearance that allows them to be visually distinguishable from each other. This facilitates detection when the stacked inductor 1 flips during installation.

[0045] The low-strength layers 11-2 to 11-7 in the low-strength layers 11 constitute low-strength intermediate layers for the surrounding portion 23 of the coil conductor 20. Therefore, the reference numerals "11-2" to "11-7" can also be used for low-strength intermediate layers.

[0046] Furthermore, low-strength layers 11-1, 11-8, and 11-9 constitute a first low-strength outer layer and a second low-strength outer layer. These first and second low-strength outer layers are located adjacent to the first end face layer 9 and the second end face 10, respectively, and sandwich the aforementioned low-strength intermediate layers 11-2 to 11-7. Therefore, the reference numeral "11-1" is also used for the first low-strength outer layer, and reference numerals "11-8" and "11-9" are also used for the second low-strength outer layer.

[0047] Hereinafter, the formation of each of the winding portions 23, etc. constituting the coil conductor 20 will be described in order from the low-strength layer 11-1 toward the low-strength layers 11-9.

[0048] <1> No conductor is provided in the first low-strength outer layer 11-1 adjacent to the first end face layer 9.

[0049] <2> In the low-strength intermediate layer 11-2, a first end conductor sheet 21-1 is provided, which is part of the first end 21 of the coil conductor 20 that provides the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-2 in the thickness direction, i.e. the stacking direction.

[0050] Although not shown, in the low-strength intermediate layer 11-2, a second end conductor sheet is also provided at a position symmetrical to the first end conductor sheet 21-1, which becomes part of the second end 22 of the coil conductor 20 that provides the second terminal electrode 28.

[0051] <3> In the low-strength intermediate layer 11-3, a first end conductor sheet 21-2 is provided to be part of the first end 21 that provides the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-3 in the thickness direction.

[0052] Additionally, in the low-strength intermediate layer 11-3, a second end conductor sheet 22-2 is provided, which serves as part of the second end 22 of the second terminal electrode 28, extending through the low-strength intermediate layer 11-3 in the thickness direction.

[0053] At the interface between the low-strength intermediate layers 11-2 and 11-3, a surrounding portion 23-1 is provided, one end of which is connected to the second end conductor piece 22-2, and a through-hole pad 25-1 is provided at the other end of the surrounding portion 23-1. Although the actual form is not shown, a through-hole conductor 24-1 is provided, extending through the low-strength intermediate layer 11-3 in the thickness direction, in a manner connected to the through-hole pad 25-1.

[0054] <4> In the low-strength intermediate layer 11-4, a first end conductor sheet 21-3 is provided to be part of the first end 21 that provides the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-4 in the thickness direction.

[0055] Additionally, a second end conductor sheet 22-3 is provided in the low-strength intermediate layer 11-4, which is part of the second end 22 that provides the second terminal electrode 28, in a state that extends through the low-strength intermediate layer 11-4 in the thickness direction.

[0056] A surrounding portion 23-2 is provided at the interface between the low-strength intermediate layers 11-3 and 11-4, and through-hole pads 25-2 and 25-3 are provided at both ends of the surrounding portion 23-2. The through-hole pad 25-2 is connected to the aforementioned through-hole conductor 24-1. On the other hand, a through-hole conductor 24-2 is provided that penetrates the low-strength intermediate layer 11-4 in the thickness direction, in a manner connected to the through-hole pad 25-3.

[0057] <5> In the low-strength intermediate layer 11-5, a first end conductor sheet 21-4 is provided to be part of the first end 21 that provides the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-5 in the thickness direction.

[0058] Additionally, a second end conductor sheet 22-4, which serves as part of the second end 22 of the second terminal electrode 28, is provided in the low-strength intermediate layer 11-5, extending through the low-strength intermediate layer 11-5 in the thickness direction.

[0059] A surrounding portion 23-3 is provided at the interface between the low-strength intermediate layers 11-4 and 11-5, and through-hole pads 25-4 and 25-5 are provided at both ends of the surrounding portion 23-3. The through-hole pad 25-4 is connected to the aforementioned through-hole conductor 24-2. On the other hand, a through-hole conductor 24-3 is provided that penetrates the low-strength intermediate layer 11-5 in the thickness direction, in a manner connected to the through-hole pad 25-5.

[0060] <6> In the low-strength intermediate layer 11-6, a first end conductor sheet 21-5 is provided to be part of the first end 21 of the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-6 in the thickness direction.

[0061] Additionally, a second end conductor sheet 22-5 is provided in the low-strength intermediate layer 11-6, which is in a state that penetrates the low-strength intermediate layer 11-6 in the thickness direction, and becomes part of the second end 22 of the second terminal electrode 28.

[0062] At the interface between the low-strength intermediate layers 11-5 and 11-6, a surrounding portion 23-4 is provided, and through-hole pads 25-6 and 25-7 are provided at both ends of the surrounding portion 23-4. The through-hole pad 25-6 is connected to the aforementioned through-hole conductor 24-3. On the other hand, a through-hole conductor 24-4 is provided, extending through the low-strength intermediate layer 11-6 in the thickness direction, in a manner connected to the through-hole pad 25-7.

[0063] <7> In the low-strength intermediate layer 11-7, a first end conductor sheet 21-6 is provided to be part of the first end 21 of the first terminal electrode 27, in a state that extends through the low-strength intermediate layer 11-7 in the thickness direction.

[0064] Additionally, in the low-strength intermediate layer 11-7, a second end conductor sheet 22-6 is provided, which serves as part of the second end 22 of the second terminal electrode 28, extending through the low-strength intermediate layer 11-7 in the thickness direction.

[0065] At the interface between the low-strength intermediate layers 11-6 and 11-7, a surrounding portion 23-5 connected to the first end conductor sheet 21-6 is provided, and a through-hole pad 25-8 is provided at the end of the surrounding portion 23-5. The through-hole pad 25-8 is connected to the aforementioned through-hole conductor 24-4.

[0066] <8> No conductors are provided in the second low-strength outer layers 11-8 and 11-9. The second end face layer 10 is configured adjacent to the second low-strength outer layer 11-9.

[0067] In the patterning of the various parts of the coil conductor 20 and the low-strength intermediate layers 11-2 to 11-7, for example, photolithography, semi-additive method, screen printing, transfer method, etc.

[0068] In the actual manufacturing process, a master laminate capable of being cut to remove multiple component bodies 2 is fabricated. By cutting this master laminate, laminate sheets that become the component bodies 2 for each multilayer inductor 1 are obtained. Furthermore, if the end face layers 9 and 10 and the low-strength layer 11 contain glass, the laminate sheets are then fired. If the end face layers 9 and 10 and the low-strength layer 11 are primarily composed of resin, a process for curing the resin is then performed. The component bodies 2 thus obtained are then subjected to tumbling grinding as needed, followed by the formation of coatings 29 and 30, thus completing the multilayer inductor 1.

[0069] The stacked inductor 1 according to the first embodiment described above also has the following features.

[0070] The coil axis provided by the coil conductor 20 extends in a direction orthogonal to the first end face 3 and the second end face 4 of the component body 2. Therefore, when the multilayer inductor 1 is mounted on the mounting substrate, the direction of the magnetic flux generated by the coil conductor 20 is parallel to the mounting surface.

[0071] In this way, if the direction of the magnetic flux is parallel to the mounting surface, the mounting substrate will not block the magnetic flux, thus allowing the electrical characteristics to approach ideal values. Moreover, when the magnetic flux is blocked, the reverse current flows only through the amount of blocked magnetic flux, increasing the resistance and decreasing the Q value.

[0072] Additionally, if referring to Figure 3To explain, it is preferable that the total thickness (T1+T2) of the first end face layer 9 and the first low strength outer layer 11-1 and the total thickness (T3+T4) of the second end face layer 10 and the second low strength outer layers 11-8 and 11-9 are equal to each other, but even if they are different, the difference is preferably less than 3 μm.

[0073] In this embodiment, to improve mechanical strength, the first end face layer 9 and the first low-strength outer layer 11-1, and the second end face layer 10 and the second low-strength outer layers 11-8 and 11-9 in the component body 2 are arranged in an asymmetrical configuration. However, as described above, by making (T1+T2) = (T3+T4), the coil conductor 20 in the component body 2 is located at the center of the entire multilayer inductor 1 and can be configured in a point-symmetric manner. Therefore, the magnetic flux emitted from the multilayer inductor 1 can be made symmetrical. Moreover, if the coil conductor is configured asymmetrically within the component body, the magnetic flux emitted from the multilayer inductor also becomes asymmetrical, and even if undesirable, the influence on other electronic components also becomes asymmetrical.

[0074] Additionally, if referring to Figure 3 To explain, it is preferable to compare at the same position in the direction connecting the top surface 7 and the bottom surface 8, from the first terminal electrode 27 and the second terminal electrode 28 (refer to...) Figure 1 The distance L1 from the edge 31 on the first end face 3 side of each of the first terminal electrodes 27 and 28 to the first end face 3 is equal to the distance L2 from the edge 32 on the second end face 4 side of each of the first terminal electrodes 27 and 28 to the second end face 4.

[0075] According to the above structure, the coil conductor 20 inside the main body 2 is located at the center of the entire multilayer inductor 1 and can be configured in a point-symmetric manner. Therefore, the magnetic flux emitted from the multilayer inductor 1 can be made to have a symmetrical shape.

[0076] Additionally, if referring to Figure 3 To illustrate, in this embodiment, when comparing the same position in the direction connecting the top surface 7 and the bottom surface 8, the distance T1 from the interface between the first end face layer 9 and the first low-strength outer layer 11-1 to the first end face 3 is longer than the distance T2 from the interface between the first end face layer 9 and the first low-strength outer layer 11-1 to the edge of the first end face 3 side of the first terminal electrode 27 and the second terminal electrode 28, respectively. The distance T3 from the interface between the second end face layer 10 and the second low-strength outer layer 11-9 to the second end face 4 is shorter than the distance T4 from the interface between the second end face layer 10 and the second low-strength outer layer 11-9 to the edge of the second end face 4 side of the first terminal electrode 27 and the second terminal electrode 28, respectively.

[0077] As a result of the structure described above, the coil conductor 20 within the main body 2 can be located at the center of the entire stacked inductor 1 and can be configured in a point-symmetric manner.

[0078] Next, refer to Figure 4 and Figure 5 The form of a multilayer inductor that is easily produced during the actual manufacture of a multilayer inductor possessing the features of the present invention will be described. Figure 4 and Figure 5 In the middle, to and Figure 3 Elements shown that correspond to each other are labeled with the same reference numerals, and repeated descriptions are omitted. Furthermore, in Figure 4 and Figure 5 The text exaggerates the features it intends to illustrate.

[0079] Figure 4 This is a side view showing the stacked inductor 1a according to the second embodiment of the present invention from the first side direction 5. Figure 4 In the stacked inductor 1a shown, when viewed from a direction orthogonal to the first side surface 5 or the second side surface 6, the intervals A1 and A2 between the interface 33 of the first end face layer 9 and the low strength layer 11 and the interface 34 of the second end face layer 10 and the low strength layer 11 gradually shorten (A1 > A2) as it moves from the bottom surface 8 toward the top surface 7. This configuration helps stabilize the stacked inductor 1a during installation.

[0080] Figure 4 The shape shown arises from the location of the terminal electrodes 27 and 28 in the component body 2. Specifically, the terminal electrodes 27 and 28 are located biased towards the bottom surface 8 of the component body 2. Therefore, if pressure is applied to the component body 2 along the stacking direction, the portion without the terminal electrodes 27 and 28 is compressed more significantly compared to the portion where the terminal electrodes 27 and 28 are present. As a result, [the desired shape is achieved]. Figure 4 The shape shown.

[0081] Figure 5 This is a side view showing the stacked inductor 1b of the third embodiment of the present invention from the first side direction 5. Figure 5 In the stacked inductor 1b shown, when viewed from a direction orthogonal to the first side surface 5 or the second side surface 6, the length L3 of the first end face layer 9 in the extension direction of the first end face 3 is shorter than the length L4 of the second end face layer 10 in the extension direction of the second end face 4.

[0082] Figure 5The shape shown originates from the manufacturing process described below. As described above, in the actual manufacturing process of the multilayer inductor 1b, a master laminate capable of removing multiple component bodies 2 by cutting is produced. By cutting this master laminate, laminate sheets that become the component bodies 2 for each multilayer inductor 1 are obtained. When cutting the master laminate, to prevent product breakage, a cutting blade is inserted from the thicker first end face layer 9 side. Since the cutting blade has a tapered cross-sectional shape, the first end face layer 9 side contacted by the root of the cutting blade is... Figure 5 The vertical direction within is compressed more strongly. Due to these processing conditions, the desired result is achieved. Figure 5 The shape shown.

[0083] The present invention has been described above in connection with the illustrated embodiments, but various other modifications are possible within the scope of the present invention. For example, in the illustrated embodiment, the thickness of the first end face layer 9 is greater than the thickness of the second end face layer 10, provided that both the first end face layer 9 and the second end face layer 10 are present, but the thickness of the second end face layer 10 may also be 0, that is, there may be no second end face layer.

[0084] Furthermore, the embodiments described in this specification are illustrative, and structural substitutions or combinations can be made between different embodiments.

Claims

1. A multilayer inductor, wherein, have: The main body of the component is made of non-conductive material and has a cuboid or approximately cuboid shape with a stacked structure. It has a first end face and a second end face that are opposite each other at the ends in the stacking direction, a first side face and a second side face that connect the first end face and the second end face and are opposite each other, and a top surface and a bottom surface that connect the first end face and the second end face and the first side face and the second side face respectively and are opposite each other. The coil conductor has a first end and a second end exposed on the outer surface of the component body, which are opposite to each other, and has a surrounding portion disposed inside the component body and extending parallel to the first end face and the second end face; The first terminal electrode is configured to include the first end of the coil conductor; and The second terminal electrode is configured to include the second end of the coil conductor. The main body of the component has a first end face layer providing the first end face, a second end face layer providing the second end face, and a low-strength layer with lower rigidity than the first end face layer and the second end face layer. The low-strength layer has a low-strength intermediate layer for the surrounding portion where the coil conductor is disposed, a first low-strength outer layer adjacent to the first end face layer, and a second low-strength outer layer adjacent to the second end face layer, wherein the first low-strength outer layer and the second low-strength outer layer are located sandwiching the low-strength intermediate layer. The thickness of the first end face layer is greater than the thickness of the second end face layer. When comparing the same positions in the direction connecting the top surface and the bottom surface, the distance from the edge of the first end face of each of the first terminal electrode and the second terminal electrode to the first end face is equal to the distance from the edge of the second end face of each of the first terminal electrode and the second terminal electrode to the second end face. The combined thickness of the first end face layer and the first low-strength outer layer is equal to the combined thickness of the second end face layer and the second low-strength outer layer.

2. The multilayer inductor according to claim 1, wherein, The first end face layer and the second end face layer have an appearance that allows them to be visually distinguished from each other, as do the low strength layer.

3. The multilayer inductor according to claim 1 or 2, wherein, The first end face layer is more than 3 μm thicker than the second end face layer.

4. The multilayer inductor according to any one of claims 1 to 3, wherein, The first terminal electrode extends across a portion of the first side surface and the bottom surface, and the second terminal electrode extends across a portion of the second side surface and the bottom surface.

5. The multilayer inductor according to claim 1 or 4, wherein, When comparing the same position in the direction connecting the top surface and the bottom surface, the distance from the interface between the first end face layer and the first low-strength outer layer to the first end face is longer than the distance from the interface between the first end face layer and the first low-strength outer layer to the respective first end face edge of the first terminal electrode and the second terminal electrode, and the distance from the interface between the second end face layer and the second low-strength outer layer to the second end face is shorter than the distance from the interface between the second end face layer and the second low-strength outer layer to the respective second end face edge of the first terminal electrode and the second terminal electrode.

6. The multilayer inductor according to any one of claims 1 to 5, wherein, When viewed from a direction orthogonal to the first or second side, the interval between the interface of the first end face layer and the low strength layer and the interface of the second end face layer and the low strength layer gradually shortens as one moves from the bottom surface toward the top surface.

7. The multilayer inductor according to any one of claims 1 to 6, wherein, When viewed from a direction orthogonal to the first side or the second side, the length of the first end face layer in the extension direction of the first end face is shorter than the length of the second end face layer in the extension direction of the second end face.

8. The multilayer inductor according to any one of claims 1 to 7, wherein, The coil axis provided by the coil conductor extends in a direction orthogonal to the first end face and the second end face.

9. The multilayer inductor according to any one of claims 1 to 8, wherein, The first terminal electrode has a first coating formed to cover the first end, and the second terminal electrode has a second coating formed to cover the second end.

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