Stacked inductor

Abstract

A laminated inductor (1) includes: a green body (10) formed by laminating a plurality of insulating layers (15) in a lamination direction (T); and an inductor (20) disposed inside the green body. The inductor includes an inductor conductor layer (25) laminated with the insulating layers (15) in the lamination direction (T). When a cross section of the green body and the inductor parallel to the lamination direction (T) and perpendicular to a direction in which the inductor conductor layer extends is observed, in at least one cross section of the inductor conductor layer (25), there is a columnar portion (40) that contacts the insulating layers (15) on both a first main surface (25a) and a second main surface (25b) that are opposite each other in the lamination direction (T), and there are two or more gaps (50) provided between at least the first main surface (25a) of the inductor conductor layer (25) and the insulating layers (15), the gaps being isolated by the columnar portion (40) in a direction along the first main surface (25a).

Description

Technical Field

[0001] This invention relates to multilayer inductors. Background Technology

[0002] Patent Document 1 discloses a stacked coil component comprising: a blank formed by stacking multiple magnetic layers; a coil, which is formed by electrically connecting multiple coil conductors and disposed inside the blank; and multiple terminal electrodes disposed on the outer surface of the blank and electrically connected to the coil. The coil conductors are characterized in that they have: portions that contact the blank surrounding the coil conductors; and portions that are separated from the blank surrounding the coil conductors.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-191904

[0004] In the laminated coil component described in Patent Document 1, gaps are defined in the portion where the coil conductor is separated from the blank. Therefore, even when the coil conductor undergoes thermal expansion at high temperatures, this expansion can be absorbed in the gaps, thus suppressing the generation of internal stress in the blank caused by the expanding coil conductor.

[0005] However, for example, when mounting the laminated coil component described in Patent Document 1 onto a substrate, the coil conductor is subjected to significant stress due to the impact of the mounting machine, which can easily cause the gaps to flatten. As a result, defects such as flattened coil conductors and cracks in the blank may occur.

[0006] Furthermore, the aforementioned problems are not limited to stacked coil components in which a spiral coil, formed by stacking multiple coil conductors, is arranged inside a blank, but are common problems in stacked inductors in which an inductor, formed by stacking multiple inductor conductor layers, is arranged inside a blank. Summary of the Invention

[0007] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a multilayer inductor that provides a low stress on the inductor conductor layer even when there is a gap between the inductor conductor layer and the insulating layer.

[0008] The multilayer inductor of the present invention comprises: a blank formed by stacking a plurality of insulating layers in a stacking direction; and an inductor disposed inside the blank. The inductor includes an inductor conductor layer stacked together with the insulating layers in the stacking direction. When viewing cross-sections of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends, at least one cross-section of the inductor conductor layer contains columnar portions that contact the insulating layer on both a first main surface and a second main surface facing each other in the stacking direction, and at least two gaps separated by the columnar portions in the direction along the first main surface are provided between at least the first main surface of the inductor conductor layer and the insulating layer.

[0009] According to the present invention, a multilayer inductor can be provided in which the stress applied to the inductor conductor layer is relatively small even when a gap is provided between the inductor conductor layer and the insulating layer. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the first embodiment of the present invention.

[0011] Figure 2 This is a perspective view schematically illustrating an example of a stacked inductor according to the first embodiment of the present invention.

[0012] Figure 3 yes Figure 1 An example of a cross-sectional view of a multilayer inductor located at line III-III.

[0013] Figure 4 It's enlarged. Figure 1 A sectional view of the portion shown in IV.

[0014] Figure 5 This is a schematic diagram used to illustrate stress simulation.

[0015] Figure 6 A represents the result of stress simulation in a multilayer inductor where the conductor layer does not have columnar sections. Figure 6 B is the result of stress simulation in a stacked inductor with a columnar portion in the center of the inductor conductor layer.

[0016] Figure 7 This is a cross-sectional view schematically illustrating an example of a stacked inductor according to a second embodiment of the present invention.

[0017] Figure 8 It's enlarged. Figure 7 A sectional view of the portion shown in VIII.

[0018] Figure 9 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to a third embodiment of the present invention.

[0019] Figure 10 yes Figure 9 An example of a cross-sectional view of a stacked inductor located at the position of the XX line.

[0020] Figure 11 It's enlarged. Figure 9 A sectional view of the portion shown in XI.

[0021] Figure 12 This is a schematic diagram showing the baseline used to measure the width of the gap.

[0022] Figure 13 This is a schematic diagram illustrating the method for measuring the linewidth of a gap.

[0023] Figure 14 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 14 B represents the stress simulation result in a multilayer inductor located near the outer periphery of the inductor conductor layer in the columnar section.

[0024] Figure 15 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the fourth embodiment of the present invention.

[0025] Figure 16 yes Figure 15 An example of a cross-sectional view of a stacked inductor located at the position of the XVI-XVI line.

[0026] Figure 17 It's enlarged. Figure 15 A sectional view of the portion shown in XVII.

[0027] Figure 18 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 18 B represents the stress simulation results in a multilayer inductor located near the inner periphery of the inductor conductor layer in the columnar section.

[0028] Figure 19 It is a graph showing the relationship between the gap linewidth ratio on the inner circumference side and the stress applied to the conductor layer of the inductor.

[0029] Figure 20 A, Figure 20 B and Figure 20 C is a schematic diagram used to illustrate the relationship between the position of the columnar portion and the stress applied to the conductor layer of the inductor.

[0030] Figure 21This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the fifth embodiment of the present invention.

[0031] Figure 22 yes Figure 21 An example of a cross-sectional view of a multilayer inductor located at the position of the XXII-XXII line.

[0032] Figure 23 It's enlarged. Figure 21 A sectional view of the portion shown in section XXIII.

[0033] Figure 24 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 24 B represents the stress simulation results in the stacked inductor located near the outer and inner peripheries of the inductor conductor layer, respectively.

[0034] Figure 25 It is a graph showing the relationship between the gap linewidth ratio on the inner circumference side and the stress applied to the conductor layer of the inductor.

[0035] Figure 26 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the sixth embodiment of the present invention.

[0036] Figure 27 It's enlarged. Figure 26 A sectional view of the portion shown in XXVII.

[0037] Figure 28 A and Figure 28 B is the result of stress simulation under the condition that the overall void linewidth ratio of the conductor layer changes in a stacked inductor with a columnar section in the center of the conductor layer.

[0038] Figure 29 It is a graph showing the relationship between the overall void linewidth ratio of the conductor layer in a multilayer inductor with a columnar portion in the center of the conductor layer and the stress applied to the conductor layer.

[0039] Figure 30 It is a graph showing the relationship between the overall void linewidth ratio of the conductor layers in a multilayer inductor with different column positions and the stress applied to the conductor layers of the inductor.

[0040] Figure 31 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the seventh embodiment of the present invention.

[0041] Figure 32 A is the result of stress simulation in a multilayer inductor with two columnar isolation gaps. Figure 32B is the result of stress simulation in a multilayer inductor with three columnar isolation gaps.

[0042] Figure 33 A and Figure 33 B is a schematic diagram representing an example of a printing process.

[0043] Figure 34 This is a schematic diagram illustrating an example of a lamination and pressure welding process.

[0044] Figure 35 This is a schematic diagram illustrating an example of the firing process.

[0045] Figure 36 A, Figure 36 B and Figure 36 C is a schematic diagram representing another example of the printing process.

[0046] Figure 37 This is a schematic diagram illustrating another example of the lamination and pressure welding process.

[0047] Figure 38 This is a schematic diagram illustrating another example of the firing process.

[0048] Figure 39 A is a top sectional view schematically illustrating a first modified example of the multilayer inductor of the present invention. Figure 39 B is a side sectional view schematically illustrating a first modified example of the stacked inductor of the present invention.

[0049] Figure 40 A is a top sectional view schematically illustrating a second modified example of the multilayer inductor of the present invention. Figure 40 B is a side sectional view schematically illustrating a second modified example of the stacked inductor of the present invention.

[0050] Explanation of reference numerals in the attached figures

[0051] 1, 2, 3, 4, 5, 6, 7, 8, 9…Laminated inductor; 10…Bulk body; 10a…First main surface; 10b…Second main surface; 10c…First end face; 10d…Second end face; 10e…First side face; 10f…Second side face; 15…Insulating layer; 20…Inductor; 25…Inductor conductor layer; 25a…First main surface; 25b…Second main surface; 31…First external electrode; 32…Second external electrode; 40…Columnar portion; 50…Gap; 55…Covering layer; 110…Laminated body; 115…Ceramic green sheet; 125…Conductive paste layer; 150…Resin paste layer; 155…Insulating paste layer; BL…Base line; CX…Coil shaft; SM…Side edge portion; L…Length direction; W…Width direction; T…Lamination direction Detailed Implementation

[0052] The multilayer inductor of the present invention will now be described. It should be noted that the present invention is not limited to the embodiments described below, and can be appropriately modified without changing the spirit of the invention. Furthermore, structures obtained by combining two or more of the preferred configurations described in the following embodiments are also part of the present invention.

[0053] In the multilayer inductor of the present invention, a feature is that, when viewing a cross-section of the blank parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends, two or more gaps separated by columnar portions in the direction along the first main surface are provided between at least a first main surface of the inductor conductor layer and the insulating layer. Furthermore, the multilayer inductor of the present invention does not need to satisfy the above-described features in all cross-sections parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends; it is sufficient that the above-described features are satisfied in any one cross-section.

[0054] The embodiments shown below are illustrative, and of course, different substitutions or combinations of the components shown in the embodiments are possible. In the second embodiment and thereafter, descriptions of matters common to the first embodiment are omitted, and only the differences are explained. In particular, the same effects based on the same structure will not be mentioned sequentially in each embodiment.

[0055] In the embodiments shown below, in all cross-sections of the inductor conductor layer present in the blank in the above-described direction and in the cross-section of the inductor, two or more gaps separated by columnar portions are provided between the first main surface of the inductor conductor layer and the insulating layer. However, as long as two or more gaps separated by columnar portions are provided between the first main surface of the inductor conductor layer and the insulating layer in at least one cross-section of the inductor conductor layer, there may also be cross-sections of the inductor conductor layer in which no gaps are provided between the first main surface of the inductor conductor layer and the insulating layer, or there may be cross-sections of the inductor conductor layer in which only one gap is provided.

[0056] Furthermore, in the embodiments shown below, no gap is provided between the second main surface of the inductor conductor layer and the insulating layer. However, if in at least one cross-section of the inductor conductor layer, two or more gaps separated by columnar portions are provided between the first main surface of the inductor conductor layer and the insulating layer, a cross-section of the inductor conductor layer in which a gap is provided between the second main surface of the inductor conductor layer and the insulating layer may also exist. In this case, two or more gaps separated by columnar portions along the direction of the second main surface may be provided between the second main surface of the inductor conductor layer and the insulating layer, or only one gap may be provided.

[0057] In the following description, unless otherwise specified, each embodiment will be referred to as "the multilayer inductor of the present invention".

[0058] In this specification, terms indicating the relationship between elements (such as "perpendicular", "parallel", "orthogonal") and terms indicating the shape of elements are not merely expressions of a strict meaning, but rather imply substantially the same range, including expressions of a difference of a few percent.

[0059] The accompanying drawings are schematic diagrams, and their dimensions, aspect ratios, and scales may sometimes differ from the actual product. The same reference numerals are used for identical or equivalent parts in the drawings. Furthermore, the same reference numerals are used for the same elements across different drawings, omitting redundant descriptions.

[0060] [First Implementation Method]

[0061] In the multilayer inductor according to the first embodiment of the present invention, in at least one cross-section of the inductor conductor layer, two gaps separated by columnar portions are provided between the first main surface of the inductor conductor layer and the insulating layer.

[0062] Figure 1 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the first embodiment of the present invention. Figure 2 This is a perspective view schematically illustrating an example of a stacked inductor according to the first embodiment of the present invention. Figure 3 yes Figure 1 An example of a cross-sectional view of a multilayer inductor located at line III-III. Furthermore, Figure 1 Equivalent to Figure 2 as well as Figure 3 A cross-sectional view of the stacked inductor located at line II.

[0063] Figure 1 as well as Figure 2 The stacked inductor 1 shown includes a blank 10 and an inductor 20 disposed inside the blank 10 (see reference). Figure 1 ).exist Figure 2 In the example shown, the multilayer inductor 1 also includes a first external electrode 31 and a second external electrode 32.

[0064] The blank 10 is formed by stacking multiple insulating layers 15 in the stacking direction T (see reference). Figure 1 as well as Figure 3 It is composed of ). In addition, such as Figure 1 As shown, the boundaries between the insulating layers 15 are not actually clearly visible.

[0065] Materials constituting the insulating layer 15 include, for example, magnetic materials such as ferrite.

[0066] exist Figures 1-3In this design, the length direction, width direction, and stacking direction of the multilayer inductor 1 and the blank 10 are respectively represented as the L direction, W direction, and T direction. Preferably, the length direction L, the width direction W, and the stacking direction T are orthogonal to each other. The mounting surface of the multilayer inductor 1 is, for example, a surface parallel to the length direction L and the width direction W (LW surface).

[0067] exist Figure 2 In the example shown, the blank 10 has a cuboid shape. In this case, the blank 10 has: a first main surface 10a and a second main surface 10b opposite each other in the stacking direction T; a first end surface 10c and a second end surface 10d opposite each other in the length direction L orthogonal to the stacking direction T; and a first side surface 10e and a second side surface 10f opposite each other in the width direction W orthogonal to the stacking direction T and the length direction L.

[0068] The blank 10 may also have rounded corners and edges. The corners are the parts where three surfaces of the blank 10 intersect, and the edges are the parts where two surfaces of the blank 10 intersect.

[0069] Inductor 20 includes an inductor conductor layer 25 stacked together with insulating layer 15 in the stacking direction T (see reference). Figure 1 as well as Figure 3 ).

[0070] exist Figure 1 as well as Figure 3 In the example shown, the inductor 20 is formed by stacking multiple inductor conductor layers 25 together with the insulating layer 15 in the stacking direction T (see Figure 15). Figure 1 as well as Figure 3 The inductor 20 is constructed by electrical connection. Adjacent inductor conductor layers 25 in the stacking direction T are electrically connected to each other via through-hole conductors (not shown). Therefore, the inductor 20 can be said to be constructed by electrically connecting multiple inductor conductor layers 25 stacked together with the insulating layer 15 in the stacking direction T via through-hole conductors (not shown). When viewed from the stacking direction T, the inductor conductor layers 25 have a helical shape wound around a coil axis (not shown) parallel to the stacking direction T.

[0071] Materials constituting the conductor layer 25 of the inductor include, for example, conductive materials such as Au, Ag, Pd, Cu, and Ni. Figure 1 In the example shown, the cross-sectional shape of the inductor conductor layer 25 is approximately trapezoidal, but the cross-sectional shape of the inductor conductor layer 25 is not particularly limited. For example, the cross-sectional shape of the inductor conductor layer 25 could also be approximately elliptical.

[0072] The first external electrode 31 and the second external electrode 32 are disposed on the outer surface of the blank 10 and are electrically connected to the inductor 20.

[0073] exist Figure 2 In the example shown, the first external electrode 31 is configured to cover the first end face 10c of the blank 10, extending from the first end face 10c and covering a portion of the first main face 10a, a portion of the second main face 10b, a portion of the first side face 10e, and a portion of the second side face 10f. On the other hand, the second external electrode 32 is configured to cover the second end face 10d of the blank 10, extending from the second end face 10d and covering a portion of the first main face 10a, a portion of the second main face 10b, a portion of the first side face 10e, and a portion of the second side face 10f.

[0074] The inductor 20 is electrically connected to the first external electrode 31 through the first end face 10c of the blank 10, and the inductor 20 is electrically connected to the second external electrode 32 through the second end face 10d of the blank 10.

[0075] Materials used to form the first external electrode 31 and the second external electrode 32 include conductive materials such as Au, Ag, Pd, Cu, and Ni. Furthermore, a plating layer may be provided on the surface of the first external electrode 31 and the second external electrode 32.

[0076] Figure 4 It's enlarged. Figure 1 A sectional view of the portion shown in IV.

[0077] like Figure 1 As shown, in the direction parallel to the stacking direction T and extending along the inductor conductor layer 25 (in Figure 1 When the cross-section of the blank 10 (perpendicular to the length direction L) and the inductor 20 is shown, as... Figure 4 As shown, in the cross-section of the inductor conductor layer 25, there are columnar portions 40 that contact the insulating layer 15 through the first main surface 25a and the second main surface 25b, which are opposite each other in the stacking direction T. Furthermore, a portion 40 is provided between the first main surface 25a and the insulating layer 15 in the direction along the first main surface 25a (in... Figure 4 Two gaps 50 are separated by the columnar portion 40 in the width direction (W). For example... Figure 4 As shown, the first main surface 25a of the inductor conductor layer 25 includes not only the portion 25a1 that contacts the insulating layer 15 (in... Figure 4 In the middle, the part shown by the thick solid line), it also includes the part 25a2 that contacts the gap 50 (in Figure 4 (The part shown by the thick dashed line in the middle). Additionally, although in Figure 4 Although not shown in the diagram, when a gap 50 is provided between the second main surface 25b of the inductor conductor layer 25 and the insulating layer 15, the second main surface 25b of the inductor conductor layer 25 includes not only the portion in contact with the insulating layer 15, but also the portion in contact with the gap 50.

[0078] exist Figure 1 In the example shown, the entire cross-section of the inductor conductor layer 25 satisfies Figure 4 The configuration shown is valid, provided that at least one cross-section of the inductor conductor layer 25 satisfies Figure 4 The configuration shown is sufficient. Furthermore, regarding the method of taking the cross-section, it is not limited to any cross-section that is parallel to the stacking direction T and perpendicular to the direction in which the inductor conductor layer 25 extends. Figure 1 The WT section shown (a section parallel to the width direction W and the stacking direction T) is satisfied as long as at least one section satisfies Figure 4 The configuration shown is sufficient. The same applies to the following implementations.

[0079] In the multilayer inductor 1, even if a gap 50 is provided between the inductor conductor layer 25 and the insulating layer 15, the stress applied to the inductor conductor layer 25 can be reduced by the presence of columnar portions 40 in the inductor conductor layer 25. Therefore, for example, when the multilayer inductor 1 is mounted on a substrate, it is possible to prevent the inductor conductor layer 25 from being flattened due to the impact of the mounting machine (mounting machine) and to prevent cracks from being generated in the blank 10.

[0080] Furthermore, unlike the configuration in Patent Document 1 where a gap 50 is provided throughout the first main surface 25a of the inductor conductor layer 25 (i.e., the first main surface 25a of the inductor conductor layer 25 does not contact the insulating layer 15), the presence of columnar portions 40 in the inductor conductor layer 25 increases heat dissipation from the columnar portions 40, thereby improving the overall heat dissipation of the stacked inductor 1.

[0081] exist Figure 1 as well as Figure 4 In the example shown, a columnar portion 40 is present in the center of the inductor conductor layer 25, and gaps 50 are respectively provided at both ends of the inductor conductor layer 25 between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15. By providing gaps 50 between the inductor conductor layer 25 and the insulating layer 15, the stress generated during firing due to the shrinkage difference between the insulating layer 15 and the inductor conductor layer 25 is mitigated.

[0082] The following describes the results of stress simulation performed to confirm the stress reduction effect caused by the columnar portion 40.

[0083] Figure 5 This is a schematic diagram used to illustrate stress simulation.

[0084] like Figure 5 As shown, for a multilayer inductor with a gap 50 between the inductor conductor layer 25 and the insulating layer 15, simulation software is used to calculate the stress applied to the insulating layer 15 and the inductor conductor layer 25. The specific conditions are shown below.

[0085] • Insulation layer: Ferrite

[0086] • Inductor conductor layer: Ag100% electrode

[0087] • Software used: Femtet (registered trademark), manufactured by Murata Software Co., Ltd.

[0088] • Billet dimensions: 1608 (1.6mm × 0.8mm)

[0089] • Pressure applied: 4 MPa of pressure is applied to the top.

[0090] • Fixing conditions: Fix the bottom edge of the blank (assuming there is a base plate at the bottom of the blank).

[0091] Top and side free analysis

[0092] • Analysis Dimension: Two-dimensional analysis

[0093] • Young's modulus: Ferrite: 142.3 GPa

[0094] Ag: 73.2 GPa

[0095] • Poisson's ratio: Ferrite: 0.33

[0096] Ag: 0.38

[0097] Figure 6 A represents the result of stress simulation in a multilayer inductor where the conductor layer does not have columnar sections. Figure 6 B is the result of stress simulation in a stacked inductor with a columnar portion in the center of the inductor conductor layer.

[0098] according to Figure 6 A and Figure 6 As shown in Figure B, in the configuration where the inductor conductor layer has columnar portions, compared to the configuration where the inductor conductor layer does not have columnar portions, it can be confirmed that the stress applied to the inductor conductor layer is smaller. Furthermore, as... Figure 6 A and Figure 6 As shown in B, the upper surface of the inductor conductor layer ( Figure 4 The center of the linewidth of the second principal surface 25b is used as the stress measurement point.

[0099] [Second Implementation]

[0100] In the stacked inductor according to the second embodiment of the present invention, a covering layer containing insulating material is provided on at least a portion of the surface of the inductor conductor layer between the inductor conductor layer and the gap.

[0101] Figure 7This is a cross-sectional view schematically illustrating an example of a stacked inductor according to a second embodiment of the present invention. Figure 8 It's enlarged. Figure 7 A sectional view of the portion shown in VIII.

[0102] exist Figure 7 In the stacked inductor 2 shown, it is also related to Figure 1 The stacked inductor 1 shown is the same, observed in a direction parallel to the stacking direction T and extending along the conductor layer 25 of the inductor (in... Figure 7 When considering the cross-section of the blank 10 perpendicular to the length direction L and the inductor 20, in the cross-section of the inductor conductor layer 25, as shown... Figure 8 As shown, there are columnar portions 40 on both the first main surface 25a and the second main surface 25b, which are opposite each other in the stacking direction T, and which are in contact with the insulating layer 15. Furthermore, a portion 40 is provided between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15 in the direction along the first main surface 25a (in... Figure 8 The two gaps 50 are separated by the columnar part 40 in the width direction (W).

[0103] Furthermore, in the multilayer inductor 2, a covering layer 55 containing insulating material is provided on at least a portion of the surface of the inductor conductor layer 25 between the inductor conductor layer 25 and the gap 50.

[0104] exist Figure 7 In the example shown, the entire cross-section of the inductor conductor layer 25 satisfies Figure 8 The configuration shown is valid, provided that at least one cross-section of the inductor conductor layer 25 satisfies Figure 8 The configuration shown is sufficient.

[0105] The covering layer 55 can be disposed entirely on the surface of the inductor conductor layer 25 between the inductor conductor layer 25 and the gap 50, or it can be disposed on a portion thereof. Additionally, in Figure 8 In the example shown, a cladding layer 55 is provided on the surface of the inductor conductor layer 25 between the inductor conductor layer 25 and the gap 50 at both ends. However, the cladding layer 55 may only be provided on the surface of the inductor conductor layer 25 on either side of the gap 50.

[0106] By providing a covering layer 55 containing insulating material on the surface of the inductor conductor layer 25, the heat dissipation of the multilayer inductor 2 is improved compared to the multilayer inductor 1. Generally, insulating materials have higher thermal conductivity than air. Therefore, the greater the contact area between the inductor conductor layer 25 and the covering layer 55, the better the heat dissipation.

[0107] Preferably, the insulating material contained in the cladding layer 55 includes magnetic materials such as ferrite. By including magnetic materials in the cladding layer 55, the impedance of the stacked inductor 2 is increased.

[0108] Preferably, the insulating material included in the covering layer 55 comprises a material with the same composition as the insulating layer 15, and more preferably, it comprises a magnetic material with the same composition as the insulating layer 15. For example, it is preferable that the covering layer 55 comprises ferrite with the same composition as the insulating layer 15. By using the same material as the insulating layer 15 as the insulating material included in the covering layer 55, manufacturing difficulties can be reduced.

[0109] In this specification, "same composition" means that the materials contain the same types of elements. However, the content of elements can differ even if the types of elements are the same.

[0110] The thickness of the cladding layer 55 is not particularly limited; it can be thinner than the gap 50, thicker than the gap 50, or the same as the gap 50. Furthermore, the cladding layer 55 may not cover the entire surface of the inductor conductor layer 25 in its entire cross-section; it only needs to cover at least a portion of the inductor conductor layer 25.

[0111] [Third Implementation Method]

[0112] In the stacked inductor according to the third embodiment of the present invention, when observing the cross-section of the blank parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers sandwiching the coil shaft located in the same layer, the columnar portions present in each inductor conductor layer are close to the outer periphery of the inductor conductor layer.

[0113] Figure 9 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to a third embodiment of the present invention. Figure 10 yes Figure 9 An example of a cross-sectional view of a multilayer inductor located at the position of the XX line. Furthermore, Figure 9 Equivalent to Figure 10 A cross-sectional view of the stacked inductor located at the IX-IX line.

[0114] exist Figure 9 In the stacked inductor 3 shown, it is also related to Figure 1 The stacked inductor 1 shown is the same as that shown, such as Figure 10 As shown, when viewed from the stacking direction T, the inductor conductor layer 25 has a spiral shape wound around a coil axis (not shown) parallel to the stacking direction T.

[0115] Figure 11 It's enlarged. Figure 9 A sectional view of the portion shown in XI.

[0116] like Figure 9As shown, in the direction parallel to the stacking direction T and extending along the inductor conductor layer 25 (in Figure 9 When considering the cross-section of the blank 10 perpendicular to the length direction L and the inductor 20, in the cross-section of the inductor conductor layer 25, as shown... Figure 11 As shown, there are columnar portions 40 on both the first main surface 25a and the second main surface 25b, which are opposite each other in the stacking direction T, and which are in contact with the insulating layer 15. Furthermore, a portion 40 is provided between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15 in the direction along the first main surface 25a (in... Figure 11 The two gaps 50 are separated by the columnar part 40 in the width direction (W).

[0117] And, as Figure 11 As shown, in the cross-section of the inductor conductor layer 25 located on the same layer as the coil shaft CX, the columnar portions 40 present in each inductor conductor layer 25 are close to the outer periphery of the inductor conductor layer 25.

[0118] If the columnar portion 40 is close to the outer periphery of the inductor conductor layer 25, then as Figure 9 As shown, the gap 50 near the side of the blank 10 becomes smaller, thus suppressing the gap at the side edge of the blank 10 (in Figure 9 The cracks (shown in SM) are generated. As a result, the reliability of the multilayer inductor 3 is improved.

[0119] exist Figure 9 In the example shown, the coil shaft CX is clamped (refer to...) Figure 11 The entire cross-section of the inductor conductor layer 25 located on the same layer satisfies Figure 11 The configuration shown is acceptable, but only if at least one set of cross-sections of the inductor conductor layer 25 located on the same layer as the coil shaft CX satisfies the condition. Figure 11 The configuration shown is sufficient. Furthermore, there are no particular limitations regarding the method of taking the cross-section, as long as it passes through the coil axis CX, as long as at least one cross-section satisfies... Figure 11 The configuration shown is sufficient. The same applies to the following implementations.

[0120] like Figure 11 As shown, in the cross-section of the inductor conductor layer 25 near the outer periphery of the columnar portion 40, when the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25 is set as A, and the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25 is set as B, the gap linewidth ratio represented by A / (A+B) on the inner periphery is greater than 0.50, for example, it can be 0.55 or more, or it can be 0.60 or more. On the other hand, the gap linewidth ratio represented by A / (A+B) on the inner periphery is less than 1.0, for example, it can be 0.95 or less, or it can be 0.90 or less.

[0121] The following is a reference. Figure 12 as well as Figure 13 The method for measuring the line width of the gap 50 is explained.

[0122] Figure 12 This is a schematic diagram showing the baseline used to measure the width of the gap.

[0123] First, such as Figure 12 As shown, the baseline BL is determined along the bottom edge of the outer shape of the blank 10.

[0124] Figure 13 This is a schematic diagram illustrating a method for measuring the linewidth of the void. Furthermore, Figure 13 yes Figure 12 An enlarged view of the portion shown in XIII.

[0125] Next, as Figure 13 As shown, for each gap 50, the maximum length projected onto the baseline BL is defined as the linewidth of the gap 50. Figure 13 In the figure, A represents the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25, and B represents the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25.

[0126] Furthermore, when the gap 50 is exposed from the inductor conductor layer 25, the length of the portion exposed from the inductor conductor layer 25 is not included in the linewidth of the gap 50.

[0127] Figure 14 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 14 B represents the stress simulation result in a multilayer inductor located near the outer periphery of the inductor conductor layer in the columnar section.

[0128] according to Figure 14 A and Figure 14 As shown in Figure B, in the configuration where the columnar portion is near the outer periphery of the inductor conductor layer, although the stress applied to the inductor conductor layer is slightly greater compared to the configuration where the columnar portion is in the center of the inductor conductor layer, it is still greater than the configuration where the columnar portion is not present in the inductor conductor layer. Figure 6 Compared to the configuration shown in A, the stress applied to the inductor conductor layer is smaller.

[0129] [Fourth Implementation Method]

[0130] In the stacked inductor according to the fourth embodiment of the present invention, when observing the cross-section of the blank parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers sandwiching the coil shaft located in the same layer, the columnar portions present in each inductor conductor layer are close to the inner periphery of the inductor conductor layer.

[0131] Figure 15 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the fourth embodiment of the present invention. Figure 16 yes Figure 15 An example of a cross-sectional view of a multilayer inductor located at the XVI-XVI line. Furthermore, Figure 15 Equivalent to Figure 16 A cross-sectional view of the stacked inductors at the location of the XV-XV line.

[0132] exist Figure 15 In the stacked inductor 4 shown, it is also related to Figure 1 The stacked inductor 1 shown is the same as that shown, such as Figure 16 As shown, when viewed from the stacking direction T, the inductor conductor layer 25 has a spiral shape wound around a coil axis (not shown) parallel to the stacking direction T.

[0133] Figure 17 It's enlarged. Figure 15 A sectional view of the portion shown in XVII.

[0134] like Figure 15 As shown, in the direction parallel to the stacking direction T and extending along the inductor conductor layer 25 (in Figure 15 When considering the cross-section of the blank 10 perpendicular to the length direction L and the inductor 20, in the cross-section of the inductor conductor layer 25, as shown... Figure 17 As shown, there are columnar portions 40 on both the first main surface 25a and the second main surface 25b, which are opposite each other in the stacking direction T, and which are in contact with the insulating layer 15. Furthermore, a portion 40 is provided between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15 in the direction along the first main surface 25a (in... Figure 17 The two gaps 50 are separated by the columnar part 40 in the width direction (W).

[0135] And, as Figure 17 As shown, in the cross-section of the inductor conductor layer 25 located on the same layer as the coil shaft CX, the columnar portions 40 present in each inductor conductor layer 25 are close to the inner periphery of the inductor conductor layer 25.

[0136] Current flows through the inner periphery of the inductor conductor layer 25. Therefore, if the columnar portion 40 is close to the inner periphery of the inductor conductor layer 25, the area through which the current passes increases. As a result, heat generation caused by the current can be suppressed.

[0137] exist Figure 15 In the example shown, the coil shaft CX is clamped (refer to...) Figure 17 The entire cross-section of the inductor conductor layer 25 located on the same layer satisfies Figure 17 The configuration shown is acceptable, but only if at least one set of cross-sections of the inductor conductor layer 25 located on the same layer as the coil shaft CX satisfies the condition. Figure 17 The configuration shown is sufficient.

[0138] like Figure 17 As shown, in the cross-section of the inductor conductor layer 25 near the inner periphery of the columnar portion 40, when the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25 is set as A, and the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25 is set as B, the gap linewidth ratio represented by A / (A+B) on the inner periphery is less than 0.50, for example, it can be less than or equal to 0.45, or less than or equal to 0.40. On the other hand, the gap linewidth ratio represented by A / (A+B) on the inner periphery is greater than 0, for example, it can be greater than or equal to 0.05, or greater than or equal to 0.10.

[0139] Figure 18 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 18 B represents the stress simulation results in a multilayer inductor located near the inner periphery of the inductor conductor layer in the columnar section.

[0140] according to Figure 18 A and Figure 18 As shown in Figure B, in the configuration where the columnar portion is near the inner periphery of the inductor conductor layer, although the stress applied to the inductor conductor layer is slightly greater compared to the configuration where the columnar portion is present in the center of the inductor conductor layer, it is still greater than the configuration where the columnar portion is absent from the inductor conductor layer. Figure 6 Compared to the configuration shown in A, the stress applied to the inductor conductor layer is reduced.

[0141] Figure 19 It is a graph showing the relationship between the gap linewidth ratio on the inner circumference side and the stress applied to the conductor layer of the inductor.

[0142] from Figure 19 It can be seen that at stress measurement point 1, where the center of the linewidth on the upper surface of the inductor conductor layer is set as the stress measurement point regardless of the position of the columnar portion, the stress applied to the inductor conductor layer can be reduced by setting the gap linewidth ratio on the inner circumference side, represented by A / (A+B), to be 0.44 or higher and 0.63 or lower. On the other hand, at stress measurement point 2, where the center of the columnar portion is set as the stress measurement point according to the position of the columnar portion, the stress applied to the inductor conductor layer is stable when the gap linewidth ratio on the inner circumference side, represented by A / (A+B), is 0.44 or higher and 0.63 or lower.

[0143] Based on the above reasons, in at least one cross-section of the inductor conductor layer 25 where the columnar portion 40 is located in the center, or at least one cross-section of the inductor conductor layer 25 near the outer periphery of the columnar portion 40, or at least one cross-section of the inductor conductor layer 25 near the inner periphery of the columnar portion 40, when the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25 is set as A, and the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25 is set as B, it is preferable that the gap linewidth ratio represented by A / (A+B) on the inner periphery side is 0.44 or more and 0.63 or less. In this case, the stress applied to the inductor conductor layer 25 can be further reduced. As a result, cracks caused by the gaps 50 in the blank 10 can be reduced.

[0144] The reason why the magnitude of the stress applied to the inductor conductor layer varies depending on the position of the column is unclear, but it is speculated as follows.

[0145] Figure 20 A, Figure 20 B and Figure 20 C is a schematic diagram used to illustrate the relationship between the position of the columnar portion and the stress applied to the conductor layer of the inductor.

[0146] exist Figure 20 A, Figure 20 B and Figure 20 As shown by the dashed line in C, since the center of the inductor 20 is the column of the larger blank 10, it is inherently difficult to deform under pressure from above.

[0147] However, as Figure 20 A or Figure 20 As shown in Figure C, in the configuration of the columnar portion 40 near the inner or outer periphery of the inductor conductor layer, it is presumed that the stress balance is easily disrupted.

[0148] On the other hand, such as Figure 20 As shown in Figure B, the more centrally the columnar portion 40 is positioned in the inductor conductor layer, the more evenly the stress relief caused by the gaps 50 located at both ends of the inductor conductor layer becomes, thus facilitating stress reduction. Furthermore, the more centrally the columnar portion 40 is positioned in the inductor conductor layer, the better the balance of the magnetic flux generated from the columnar portion 40 becomes, thus improving performance.

[0149] [Fifth Implementation]

[0150] In the stacked inductor according to the fifth embodiment of the present invention, when observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers that sandwich the coil shaft located in the same layer, the columnar portion present in one inductor conductor layer is close to the outer peripheral side of the inductor conductor layer, and the columnar portion present in another inductor conductor layer is close to the inner peripheral side of the inductor conductor layer.

[0151] Figure 21 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the fifth embodiment of the present invention. Figure 22 yes Figure 21 An example of a cross-sectional view of a multilayer inductor located at the position of line XXII-XXII. Furthermore, Figure 21 Equivalent to Figure 22 A cross-sectional view of the stacked inductor located at the position of the XXI-XXI line.

[0152] exist Figure 21 In the stacked inductor 5 shown, it is also related to Figure 1 The stacked inductor 1 shown is the same as that shown, such as Figure 22 As shown, when viewed from the stacking direction T, the inductor conductor layer 25 has a spiral shape wound around a coil axis (not shown) parallel to the stacking direction T.

[0153] Figure 23 It's enlarged. Figure 21 A sectional view of the portion shown in section XXIII.

[0154] like Figure 21 As shown, in the direction parallel to the stacking direction T and extending along the inductor conductor layer 25 (in Figure 21 When considering the cross-section of the blank 10 perpendicular to the length direction L and the inductor 20, in the cross-section of the inductor conductor layer 25, as shown... Figure 23 As shown, there are columnar portions 40 on both the first main surface 25a and the second main surface 25b, which are opposite each other in the stacking direction T, and which are in contact with the insulating layer 15. Furthermore, a portion 40 is provided between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15 in the direction along the first main surface 25a (in... Figure 23 The two gaps 50 are separated by the columnar part 40 in the width direction (W).

[0155] And, as Figure 23 As shown, in the cross-section of the inductor conductor layer 25 located on the same layer as the coil shaft CX, one columnar portion 40 in the inductor conductor layer 25 is close to the outer periphery of the inductor conductor layer 25, and the other columnar portion 40 in the inductor conductor layer 25 is close to the inner periphery of the inductor conductor layer 25.

[0156] exist Figure 21 In the example shown, the coil shaft CX is clamped (refer to...) Figure 23 The entire cross-section of the inductor conductor layer 25 located on the same layer satisfies Figure 23 The configuration shown is acceptable, but only if at least one set of cross-sections of the inductor conductor layer 25 located on the same layer as the coil shaft CX satisfies the condition. Figure 23 The configuration shown is sufficient.

[0157] Figure 24 A represents the stress simulation results in a stacked inductor with a columnar portion in the center of the inductor conductor layer. Figure 24 B represents the stress simulation results in the stacked inductor located near the outer and inner peripheries of the inductor conductor layer, respectively.

[0158] according to Figure 24 A and Figure 24 As shown in Figure B, in configurations where the columnar portions are located near the outer and inner peripheries of the inductor conductor layer, the stress applied to the inductor conductor layer is slightly greater compared to configurations where the columnar portions are located in the center of the inductor conductor layer, but still greater than configurations where the columnar portions are not located in the inductor conductor layer. Figure 6 Compared to the configuration shown in A, the stress applied to the inductor conductor layer is reduced.

[0159] Figure 25 It is a graph showing the relationship between the gap linewidth ratio on the inner circumference side and the stress applied to the conductor layer of the inductor.

[0160] exist Figure 25 In, such as Figure 23 As shown, in the cross-section of the inductor conductor layer 25 near the outer periphery of the columnar portion 40, when the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25 is set as A and the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25 is set as B, the relationship between the gap linewidth ratio represented by A / (A+B) and the stress applied to the inductor conductor layer 25 is expressed.

[0161] from Figure 25 It can be seen that, with Figure 24 A and Figure 24 The results shown in B are the same. In the configuration where the columnar portion is located near the outer and inner periphery of the inductor conductor layer, the stress applied to the inductor conductor layer is slightly greater than in the configuration where the columnar portion is located in the center of the inductor conductor layer.

[0162] [Sixth Implementation Method]

[0163] In the stacked inductor according to the sixth embodiment of the present invention, when observing the cross-section of the blank parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in at least one cross-section of the inductor conductor layer, when the total linewidth of the gaps provided on the first main surface side of the inductor conductor layer is set as X and the linewidth of the inductor conductor layer is set as Y, the gap linewidth ratio of the conductor layer as represented by X / Y is 0.16 or more and 0.96 or less.

[0164] Figure 26 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the sixth embodiment of the present invention.

[0165] exist Figure 26 In the stacked inductor 6 shown, with Figure 1 Similar to the stacked inductor 1 shown, a columnar portion 40 is present in the center of the inductor conductor layer 25, and gaps 50 are respectively provided at both ends of the inductor conductor layer 25 between the first main surface 25a of the inductor conductor layer 25 and the insulating layer 15.

[0166] Figure 27 It's enlarged. Figure 26 A sectional view of the portion shown in XXVII.

[0167] like Figure 26 As shown, in the direction parallel to the stacking direction T and extending along the inductor conductor layer 25 (in Figure 26 When considering the cross-section of the blank 10 perpendicular to the length direction L and the inductor 20, in the cross-section of the inductor conductor layer 25, as shown... Figure 27 As shown, when the total linewidth of the gaps 50 provided on the first main surface 25a side of the inductor conductor layer 25 is set as X, and the linewidth of the inductor conductor layer 25 is set as Y, it is preferable that the gap linewidth ratio of the conductor layer as represented by X / Y is 0.16 or more and 0.96 or less.

[0168] exist Figure 26 as well as Figure 27 In the example shown, X = X1 + X2. Here, X1 is the linewidth of the gap 50 located on the inner periphery of the inductor conductor layer 25, and X2 is the linewidth of the gap 50 located on the outer periphery of the inductor conductor layer 25.

[0169] The line width of each 50mm gap is projected onto the baseline BL (refer to...). Figure 13 The maximum length when the inductor conductor layer 25 is projected onto the baseline BL (refer to...). Figure 13 The maximum length when ).

[0170] Figure 28 A and Figure 28B is the result of stress simulation under the condition that the overall void linewidth ratio of the conductor layer changes in a stacked inductor with a columnar section in the center of the conductor layer.

[0171] according to Figure 28 A and Figure 28 The result shown in B, even when the overall gap linewidth ratio of the conductor layer is changed, is still the same as when there are no columnar portions in the inductor conductor layer. Figure 6 Compared to the configuration shown in A, the stress applied to the inductor conductor layer can be reduced.

[0172] Figure 29 It is a graph showing the relationship between the overall void linewidth ratio of the conductor layer in a multilayer inductor with a columnar portion in the center of the conductor layer and the stress applied to the conductor layer.

[0173] according to Figure 29 In a stacked inductor with a columnar portion in the center of the inductor conductor layer, by setting the overall gap linewidth ratio of the conductor layer represented by X / Y to 0.16 or more and 0.96 or less, the stress applied to the inductor conductor layer can be reduced.

[0174] Figure 30 It is a graph showing the relationship between the overall void linewidth ratio of the conductor layers in a multilayer inductor with different column positions and the stress applied to the conductor layers of the inductor.

[0175] according to Figure 30 By setting the overall void linewidth ratio of the conductor layer represented by X / Y to 0.16 or more and 0.96 or less, regardless of the position of the columnar portion, the stress applied to the conductor layer of the inductor can be reduced.

[0176] [Seventh Implementation Method]

[0177] In the stacked inductor according to the seventh embodiment of the present invention, in at least one cross-section of the inductor conductor layer, three or more gaps separated by columnar portions are provided between the first main surface of the inductor conductor layer and the insulating layer.

[0178] Figure 31 This is a cross-sectional view schematically illustrating an example of a multilayer inductor according to the seventh embodiment of the present invention.

[0179] exist Figure 31 In the stacked inductor 7 shown, in the direction of observation that is parallel to the stacking direction T and extends with the inductor conductor layer 25 (in... Figure 31 When the cross-section is perpendicular to the length direction L, in the cross-section of the inductor conductor layer 25, a section is provided between the first main surface of the inductor conductor layer 25 and the insulating layer 15 in the direction along the first main surface (in the direction of the first main surface). Figure 31The three gaps 50 are separated by the columnar part 40 in the width direction (W).

[0180] exist Figure 31 In the example shown, three gaps 50 are provided in one cross section of the inductor conductor layer 25. However, as long as more than three gaps 50 are provided in at least one cross section of the inductor conductor layer 25, the number of gaps 50 provided in other cross sections is not particularly limited.

[0181] Figure 32 A is the result of stress simulation in a multilayer inductor with two columnar isolation gaps. Figure 32 B is the result of stress simulation in a multilayer inductor with three columnar isolation gaps.

[0182] according to Figure 32 A and Figure 32 As shown in B, even with variations in the number of gaps isolated by columnar sections, the results are the same as in the case where columnar sections are not present in the inductor conductor layer. Figure 6 Compared to the configuration shown in A, it is also possible to reduce the stress applied to the inductor conductor layer.

[0183] Hereinafter, an example of a method for manufacturing the multilayer inductor of the present invention will be described.

[0184] In the following examples, a method for manufacturing a multilayer inductor is described, in which an insulating sheet, which should be an insulating layer, is stacked to form an inductor conductor layer pattern. Furthermore, the method for manufacturing the multilayer inductor of the present invention is not particularly limited; for example, a multilayer inductor can also be manufactured by a printing stacking method that repeatedly prints insulating paste and conductive paste to sequentially form an insulating layer and an inductor conductor layer pattern.

[0185] First, as in the first embodiment of the present invention, while referring to Figures 33-35 An example of a manufacturing method for a multilayer inductor in which no cladding layer is provided on the surface of the inductor conductor layer will be described.

[0186] Figure 33 A and Figure 33 B is a schematic diagram representing an example of a printing process.

[0187] like Figure 33 As shown in Figure A, a resin paste layer 150 is formed by coating a ceramic green sheet 115 with a resin paste. Figure 33 In the example shown in A, in the conductive paste layer 125 (see reference 125), which is equivalent to the conductive paste layer described later. Figure 33 B) A resin paste layer 150 is formed at both ends, but no resin paste layer 150 is formed in the center.

[0188] like Figure 33 As shown in Figure B, a conductive paste layer 125 is formed to cover the resin paste layer 150 by coating a conductive paste such as Ag paste onto the resin paste layer 150. This forms an inductor conductor layer pattern.

[0189] Through with Figure 33 A and Figure 33 Using the same method as B, prepare a ceramic green sheet with multiple inductor conductor layer patterns.

[0190] Figure 34 This is a schematic diagram illustrating an example of a lamination and pressure welding process.

[0191] like Figure 34 As shown, ceramic green sheets with multiple inductor conductor layer patterns are laminated and bonded. Subsequently, they are monolithically formed into individual laminates 110.

[0192] Figure 35 This is a schematic diagram illustrating an example of the firing process.

[0193] like Figure 35 As shown, through firing Figure 34 The laminate 110 shown forms such that the ceramic green sheet 115 becomes the insulating layer 15, and the conductive paste layer 125 becomes the inductor conductor layer 25. Furthermore, voids 50 are formed in portions of the resin paste layer 150 by burning away the resin paste layer 150. Figure 35 In the example shown, gaps 50 are provided at both ends of the inductor conductor layer 25. Based on the above, a blank 10 with an inductor 20 disposed inside is obtained.

[0194] After firing, an external electrode is formed on the outer surface of the blank 10. Furthermore, a plating layer may also be formed on the surface of the external electrode.

[0195] After the above processes, a multilayer inductor is obtained.

[0196] Next, as in the second embodiment of the present invention, while referring to Figures 36-38 An example of a manufacturing method for a multilayer inductor in which a cladding layer is provided on the surface of the inductor conductor layer will be described.

[0197] Figure 36 A, Figure 36 B and Figure 36 C is a schematic diagram representing another example of the printing process.

[0198] like Figure 36 As shown in Figure A, a resin paste layer 150 is formed by coating a ceramic green sheet 115 with a resin paste. Figure 36 In the example shown in A, in the conductive paste layer 125 (see reference 125), which is equivalent to the conductive paste layer described later. Figure 36 C) A resin paste layer 150 is formed at both ends, but no resin paste layer 150 is formed in the center.

[0199] like Figure 36 As shown in B, an insulating paste layer 155 is formed by coating an insulating paste such as a ferrite paste onto the resin paste layer 150.

[0200] like Figure 36 As shown in Figure C, a conductive paste layer 125 is formed by coating a conductive paste such as Ag paste onto the resin paste layer 150 and the insulating paste layer 155, thereby covering the resin paste layer 150 and the insulating paste layer 155. This forms an inductor conductor layer pattern.

[0201] Through with Figure 36 A, Figure 36 B and Figure 36 Using the same method as C, prepare a ceramic green sheet with multiple inductor conductor layer patterns.

[0202] Figure 37 This is a schematic diagram illustrating another example of the lamination and pressure welding process.

[0203] like Figure 37 As shown, ceramic green sheets with multiple inductor conductor layer patterns are laminated and bonded. Subsequently, the green sheets are monolithically converted into individual laminates 110.

[0204] Figure 38 This is a schematic diagram illustrating another example of the firing process.

[0205] like Figure 38 As shown, through firing Figure 37 The laminate 110 shown here forms a ceramic green sheet 115 as an insulating layer 15, a conductive paste layer 125 as an inductor conductor layer 25, and an insulating paste layer 155 as a coating layer 55. Furthermore, voids 50 are formed in portions of the resin paste layer 150 by burning away the resin paste layer 150. Figure 38 In the example shown, gaps 50 are provided at both ends of the inductor conductor layer 25. Based on the above, a blank 10 with an inductor 20 disposed inside is obtained.

[0206] After firing, an external electrode is formed on the outer surface of the blank 10. Furthermore, a plating layer may also be formed on the surface of the external electrode.

[0207] After the above processes, a multilayer inductor is obtained.

[0208] [Other implementation methods]

[0209] The multilayer inductor of the present invention is not limited to the above embodiments. Various applications and modifications can be applied to the blank and the structure and manufacturing conditions of the inductor within the scope of the present invention.

[0210] For example, the material, shape, and size of the insulating layer can be appropriately selected according to the application. Similarly, the material, shape, and size of the inductor conductor layer can also be appropriately selected according to the application, within the scope of this invention. There is no particular limitation on the number of layers stacked in the inductor conductor layer.

[0211] In the multilayer inductor of the present invention, the number of voids in the cross-section of each inductor conductor layer can be different. Furthermore, even within the same inductor conductor layer, the number of voids in each cross-section can be different. That is, columnar portions can be formed or absent in the same inductor conductor layer. For example, even within the same inductor conductor layer, depending on the observed cross-section, it can be a cross-section with one columnar portion, a cross-section without any columnar portions, or a cross-section with two or more columnar portions, etc.

[0212] In the multilayer inductor of the present invention, the columnar portion may also be partially isolated from the insulating layer. For example, minute peeling, known as delamination, may occur between the columnar portion and the insulating layer, and minute bubbles may also be generated. Thus, in the multilayer inductor of the present invention, partial non-contact between the columnar portion and the insulating layer is allowed at an unavoidable level in the manufacturing process.

[0213] In the multilayer inductor of the present invention, the inductor may not have a coil axis parallel to the stacking direction. For example, the inductor may be constructed by stacking a linear inductor conductor layer together with an insulating layer in the stacking direction when viewed from above. In this case, the number of inductor conductor layers may be one or more.

[0214] Figure 39 A is a top sectional view schematically illustrating a first modified example of the multilayer inductor of the present invention. Figure 39 B is a side sectional view schematically illustrating a first modified example of the stacked inductor of the present invention.

[0215] exist Figure 39 A and Figure 39 In the multilayer inductor 8 shown in B, the inductor 20 is formed by stacking an inductor conductor layer 25 (e.g., a straight line parallel to the length direction L) together with an insulating layer 15 in the stacking direction T when viewed from above. The number of stacked inductor conductor layers 25 can be one or multiple layers.

[0216] Figure 40 A is a top sectional view schematically illustrating a second modified example of the multilayer inductor of the present invention. Figure 40 B is a side sectional view schematically illustrating a second modified example of the stacked inductor of the present invention.

[0217] exist Figure 40 A and Figure 40 In the multilayer inductor 9 shown in B, the inductor 20 is formed by stacking an inductor conductor layer 25 (which is curved in top view, for example, a zigzag curve) together with an insulating layer 15 in the stacking direction T. The number of stacked inductor conductor layers 25 can be one or multiple layers.

Claims

1. A multilayer inductor, wherein, have: The blank is formed by stacking multiple insulating layers in the stacking direction; and The inductor is disposed inside the aforementioned blank. The aforementioned inductor includes an inductor conductor layer, which is stacked together with the aforementioned insulating layer in the aforementioned stacking direction. When observing the cross-section of the blank and the inductor, which are parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends, a columnar portion exists in at least one cross-section of the inductor conductor layer. Both the first main surface and the second main surface of the columnar portion, which are opposite each other in the stacking direction, are in contact with the insulating layer. Furthermore, two or more gaps are provided between at least the first main surface of the inductor conductor layer and the insulating layer. These gaps are separated by the columnar portion in the direction along the first main surface.

2. The multilayer inductor according to claim 1, wherein, Between the inductor conductor layer and the gap, at least a portion of the surface of the inductor conductor layer is provided with a covering layer containing insulating material.

3. The multilayer inductor according to claim 2, wherein, The insulating material contained in the aforementioned covering layer includes magnetic material.

4. The multilayer inductor according to claim 2 or 3, wherein, The insulating material contained in the aforementioned covering layer contains materials with the same composition as the aforementioned insulating layer.

5. The multilayer inductor according to any one of claims 1 to 4, wherein, The aforementioned inductor is constructed by electrically connecting multiple inductor conductor layers that are stacked together with the aforementioned insulating layer in the aforementioned stacking direction. When the inductor is viewed from the stacking direction, the conductor layer of the inductor has a helical shape that is wound around a coil axis parallel to the stacking direction.

6. The multilayer inductor according to claim 5, wherein, When observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers located in the same layer as the coil shaft, the columnar portions present in each of the inductor conductor layers are present in the center of the inductor conductor layer.

7. The multilayer inductor according to claim 5, wherein, When observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers located in the same layer as the coil shaft, the columnar portions present in each of the inductor conductor layers are close to the outer periphery of the inductor conductor layer.

8. The multilayer inductor according to claim 5, wherein, When observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers located in the same layer as the coil shaft, the columnar portions present in each of the inductor conductor layers are close to the inner periphery of the inductor conductor layer.

9. The multilayer inductor according to any one of claims 6 to 8, wherein, In at least one cross-section of the inductor conductor layer in which the columnar portion is located at the center of the inductor conductor layer, or at least one cross-section of the inductor conductor layer in which the columnar portion is located near the outer periphery of the inductor conductor layer, or at least one cross-section of the inductor conductor layer in which the columnar portion is located near the inner periphery of the inductor conductor layer, when the linewidth of the gap located on the inner periphery of the inductor conductor layer is A and the linewidth of the gap located on the outer periphery of the inductor conductor layer is B, the ratio of the gap linewidth on the inner periphery represented by A / (A+B) is 0.44 or more and 0.63 or less.

10. The multilayer inductor according to claim 5, wherein, When observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction of extension of the inductor conductor layer, in the cross-section of at least one group of inductor conductor layers that are located in the same layer as the coil shaft, the columnar portion present in one of the inductor conductor layers is close to the outer peripheral side of the inductor conductor layer, and the columnar portion present in another of the inductor conductor layers is close to the inner peripheral side of the inductor conductor layer.

11. The multilayer inductor according to any one of claims 1 to 10, wherein, When observing the cross-section of the blank and the inductor that are parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends, in at least one cross-section of the inductor conductor layer, when the total linewidth of the gaps provided on the first main surface side of the inductor conductor layer is X and the linewidth of the inductor conductor layer is Y, the gap linewidth ratio of the conductor layer as represented by X / Y is 0.16 or more and 0.96 or less.

12. The multilayer inductor according to any one of claims 1 to 11, wherein, When observing a cross-section parallel to the stacking direction and perpendicular to the direction in which the inductor conductor layer extends, in at least one cross-section of the inductor conductor layer, at least three or more gaps separated by the columnar portion are provided between at least the first main surface of the inductor conductor layer and the insulating layer in the direction along the first main surface.

Images