Laminated inductor

Abstract

The invention provides a laminated inductor capable of suppressing reduction in reliability caused by structural defects such as cracks. This laminated inductor is provided with: a laminated body in which a plurality of insulating layers are laminated in a lamination direction, and which has a coil therein; and first and second external electrodes provided on the outer surface of the laminate and electrically connected to the coil. The coil is configured by electrically connecting a plurality of coil conductor layers stacked in a stacking direction. The plurality of coil conductor layers have M + N layers of first coil conductor layers that are continuous in the lamination direction. The first coil conductor layers each have a first parallel portion. The first parallel portions of the first coil conductor layers adjacent in the stacking direction are connected in parallel with each other via at least two conductive conductors. The M layers in the first coil conductor layers are first lead-out layers having first lead-out conductors, and the N layers are first non-lead-out layers having no first lead-out conductors. M is a natural number greater than 2, and at least one first non-lead-out layer exists between at least one group of first lead-out layers in the stacking direction.

Description

Technical Field

[0001] The present invention relates to a stacked inductor. Background Art

[0002] Patent Document 1 discloses a stacked inductor comprising: a stack composed of a plurality of insulating layers; an external electrode formed on the outside of the stack; and a coil conductor formed in a spiral shape within the stack, the coil conductor having a lead portion electrically connected to the external electrode and a coil body other than the lead portion. The coil conductor comprises a conductor pattern formed on the insulating layer and a via conductor penetrating the insulating layer and electrically connecting the plurality of conductor patterns. The conductor pattern formed on a portion of the insulating layer is a C-shaped pattern including four vertices of a substantially rectangular shape and lacking a portion of one side, and the conductor pattern formed on another portion of the insulating layer is an I-shaped pattern corresponding to a portion of the side lacking in the C-shaped pattern of the substantially rectangular shape. The conductor patterns constituting the coil body are only the C-shaped pattern and the I-shaped pattern. The coil body has a partial structure in which two or more layers of C-shaped patterns are continuously stacked, and the number of C-shaped patterns in the coil body is greater than the number of I-shaped patterns.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-162101

[0004] However, the manufacturing of a stacked inductor may include a step of cutting the stacked block using methods such as press cutting or cutting with a cutter. In the stacked inductor described in Patent Document 1, there is concern that the stress generated when cutting the stacked block could cause structural defects such as cracks in the lead conductors themselves or at the interface between the lead conductors and the insulation layer. If structural defects occur in a stacked inductor, the risk of wire breakage increases during use, thereby reducing the reliability of the stacked inductor. Summary of the Invention

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laminated inductor capable of suppressing a reduction in reliability due to structural defects such as cracks.

[0006] The stacked inductor of the present invention comprises: a stacked body having a plurality of insulating layers stacked in a stacking direction and having a coil inside; and a first external electrode and a second external electrode provided on the outer surface of the stacked body and electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductor layers, wherein the plurality of coil conductor layers are stacked together with the insulating layer in the stacking direction. The plurality of coil conductor layers include M+N layers (M and N are natural numbers) of first coil conductor layers continuous in the stacking direction. The first coil conductor layers each include a first parallel portion. The first parallel portions of the first coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two conducting conductors. The M layer of the first coil conductor layer is a first lead layer having a first lead conductor, and the N layer is a first non-lead layer not having the first lead conductor, wherein the first lead conductor is connected to the first external electrode.

[0007] In the first embodiment, M is a natural number equal to or greater than 2, and at least one first non-leading layer exists between at least one set of the first leading layers in the stacking direction.

[0008] In the second aspect, when viewed in the stacking direction, the portion of the surrounding portion of the first extraction layer that forms the current path has the same orientation and shape as the portion of the surrounding portion of the first non-extraction layer that forms the current path.

[0009] According to the present invention, it is possible to provide a multilayer inductor capable of suppressing a decrease in reliability due to structural defects such as cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a perspective view schematically showing an example of a laminated inductor according to the first embodiment of the present invention.

[0011] Figure 2 It is a perspective representation in the height direction Figure 1 Figure 1 shows a stacked inductor.

[0012] Figure 3 It is schematically represented Figure 1 An exploded top view of an example of the internal structure of a stacked inductor is shown.

[0013] Figure 4 It is a perspective representation in the width direction Figure 1 Figure 1 shows a stacked inductor.

[0014] Figure 5 This is a view showing a laminated inductor of a comparative example in a perspective manner in the height direction.

[0015] Figure 6This is a view showing a laminated inductor according to a comparative example in a perspective manner in the width direction.

[0016] Figure 7 It is along Figure 5 FIG1 is a schematic diagram showing an enlarged view of the first lead conductor in a cross section along line VII-VII in FIG1 .

[0017] Figure 8 This is an exploded plan view schematically showing an example of a laminated inductor according to the second embodiment of the present invention.

[0018] Figure 9 This is an exploded plan view schematically showing an example of a laminated inductor according to the third embodiment of the present invention.

[0019] Figure 10 It is an exploded plan view schematically showing an example of a laminated inductor according to a fourth embodiment of the present invention.

[0020] Figure 11 It is an exploded plan view schematically showing an example of a laminated inductor according to a fifth embodiment of the present invention.

[0021] Description of Reference Numerals

[0022] 1A, 1B, 1C, 1D, 1E, 101A…laminated inductor; 10A…laminated body; 11…first end surface; 12…second end surface; 13…first principal surface; 14…second principal surface; 15…first side surface; 16…second side surface; 21…first external electrode; 22…second external electrode; 30A…coil; 41…first coil conductor layer; 41M…first lead layer; 41N…first non-lead layer; 42…second coil conductor layer; 42K…second lead layer; 42L…second non-lead layer; 51…first lead conductor; 52…second lead conductor; CC, CC1, CC2, CC3, CC4, CC5, CC6, CC7, CC8, CC9…coil conductor layer; IL, IL1, IL2, IL3, IL4, IL5, IL6, IL7, IL8, IL9…insulating layer; V, V 1x 、V 1y 、V 2x 、V 2y 、V 3x 、V 3y 、V 3z 、V 4x 、V 4y 、V 4z 、V 5x 、V 5y 、V 5z 、V 6x 、V 6y 、V 7x 、V 7y 、V8x 、V 8y …conducting conductor; P1, P11, P12, P13, P14…first parallel portion; P2, P25, P26, P27, P28…second parallel portion; CR…crack; L…length direction; T…height direction; W…width direction. DETAILED DESCRIPTION

[0023] The following describes the laminated inductor of the present invention. The present invention is not limited to the following configuration and can be modified appropriately without changing the spirit of the present invention. Furthermore, a configuration combining multiple preferred configurations described below also constitutes the present invention.

[0024] In this specification, terms that indicate the relationship between elements (such as "vertical", "parallel", "orthogonal", etc.) and terms that indicate the shape of an element do not express only strict meanings, but rather mean substantially equivalent ranges, for example, expressions that also include differences of about a few percent.

[0025] The embodiments shown below are merely illustrative. It is naturally possible to partially replace or combine the structures shown in different embodiments. In the second embodiment and beyond, descriptions of matters common to the first embodiment are omitted, and only the differences are described. In particular, the same effects resulting from the same structure are not mentioned sequentially in each embodiment.

[0026] The drawings shown below are schematic diagrams, and their dimensions, aspect ratios, and scales may differ from those of actual products.

[0027] [First embodiment]

[0028] Figure 1 This is a perspective view schematically showing an example of a laminated inductor according to the first embodiment of the present invention.

[0029] Figure 1 The laminated inductor 1A shown includes a laminate 10A, a first external electrode 21, and a second external electrode 22. The laminate 10A has, for example, a rectangular parallelepiped or substantially rectangular parallelepiped shape having six faces. Figure 1 Although not shown, the laminate 10A is formed by laminating a plurality of insulating layers in a lamination direction and has a coil therein. The first external electrode 21 and the second external electrode 22 are electrically connected to the coil.

[0030] In the laminated inductor 1A and the laminated body 10A, the longitudinal direction, the height direction, and the width direction are defined as Figure 1 Here, the length direction L, the height direction T, and the width direction W are perpendicular to each other.

[0031] exist Figure 1 In the illustrated example, the laminate 10A has a first end surface 11 and a second end surface 12 facing each other in the longitudinal direction L, a first main surface 13 and a second main surface 14 facing each other in the height direction T, and a first side surface 15 and a second side surface 16 facing each other in the width direction W.

[0032] Although Figure 1 Although not shown, the laminate 10A preferably has rounded corners and ridges. The corners of the laminate 10A are where three faces of the laminate 10A intersect, and the ridges of the laminate 10A are where two faces of the laminate 10A intersect.

[0033] The first external electrode 21 and the second external electrode 22 are provided on the outer surface of the stacked body 10A.

[0034] For example, Figure 1 As shown, the first external electrode 21 covers the entire first end surface 11 of the laminate 10A and extends from the first end surface 11 to cover a portion of the first main surface 13 , a portion of the second main surface 14 , a portion of the first side surface 15 , and a portion of the second side surface 16 .

[0035] For example, Figure 1 As shown, the second external electrode 22 covers the entire second end surface 12 of the laminate 10A and extends from the second end surface 12 to cover a portion of the first main surface 13 , a portion of the second main surface 14 , a portion of the first side surface 15 , and a portion of the second side surface 16 .

[0036] When the multilayer inductor 1A having the first and second external electrodes 21 and 22 arranged as described above is mounted on a substrate, any one of the first principal surface 13 , the second principal surface 14 , the first side surface 15 , and the second side surface 16 of the multilayer body 10A serves as a mounting surface.

[0037] Figure 2 It is a perspective representation in the height direction Figure 1 Figure 1 shows a stacked inductor.

[0038] exist Figure 2 In the illustrated laminated inductor 1A, a laminate 10A includes a coil 30A therein.

[0039] The coil 30A includes a first lead conductor 51 and a second lead conductor 52 , which will be described later. The coil 30A is connected to the first external electrode 21 via the first lead conductor 51 . The coil 30A is connected to the second external electrode 22 via the second lead conductor 52 .

[0040] Figure 3 It is schematically represented Figure 1An exploded top view of an example of the internal structure of a stacked inductor is shown.

[0041] like Figure 3 As shown, the laminate 10A (see Figure 1 ) by passing through the first main surface 13 (refer to Figure 1 ) toward the second main surface 14 (refer to Figure 1 ) is composed of a plurality of insulating layers IL1, IL2, IL3, IL4, IL5, IL6, IL7, and IL8 stacked in a height direction T. Hereinafter, the insulating layers IL1, IL2, IL3, IL4, IL5, IL6, IL7, and IL8 are also collectively referred to as insulating layers IL.

[0042] exist Figure 3 In the embodiment, the insulating layer IL1 is arranged on the upper side (the second main surface 14 side of the stacked body 10A) in the stacking direction (here, the height direction T), the insulating layer IL8 is arranged on the lower side (the first main surface 13 side of the stacked body 10A) in the stacking direction, and the negative side (in the height direction T) of the main surface of each insulating layer IL is arranged on the negative side (in the height direction T) of the main surface of each insulating layer IL. Figure 3 The main surface of the stacking direction is arranged on the lower side, and the positive direction side of the height direction T (in the Figure 3 The main surface (the front side of the paper in the middle) is arranged on the upper side in the stacking direction.

[0043] Examples of the constituent material of each insulating layer IL include magnetic materials such as ferrite materials.

[0044] like Figure 3 As shown, coil conductor layers CC1, CC2, CC3, CC4, CC5, CC6, CC7, and CC8 are provided on insulating layers IL1, IL2, IL3, IL4, IL5, IL6, IL7, and IL8, respectively. Hereinafter, coil conductor layers CC1, CC2, CC3, CC4, CC5, CC6, CC7, and CC8 are also collectively referred to as coil conductor layers CC.

[0045] The coil conductor layers CC1, CC2, CC3, CC4, CC5, CC6, CC7 and CC8 are respectively provided on the main surfaces of the insulating layers IL1, IL2, IL3, IL4, IL5, IL6, IL7 and IL8, and more specifically, are provided on the positive direction side in the height direction T (on the Figure 3 On the main surface (near the front side of the paper).

[0046] The coil 30A is formed by electrically connecting a plurality of coil conductor layers CC stacked together with the insulating layer IL in the stacking direction (here, the height direction T). Figure 2 ).

[0047] The coil conductor layer CC1 of the first layer L1 is composed of the surrounding portion R1 and the first lead conductor 51. The insulating layer IL1 of the first layer L1 is provided with a via conductor V that connects the coil conductor layer CC1 and the coil conductor layer CC2. 1x and V 1y .

[0048] The coil conductor layer CC2 of the second layer L2 is composed of the surrounding portion R2. The insulating layer IL2 of the second layer L2 is provided with a via conductor V connecting the coil conductor layer CC2 and the coil conductor layer CC3. 2x and V 2y .

[0049] The coil conductor layer CC3 of the third layer L3 is composed of the surrounding portion R3. The insulating layer IL3 of the third layer L3 is provided with a via conductor V connecting the coil conductor layer CC3 and the coil conductor layer CC4. 3x and V 3y .

[0050] The coil conductor layer CC4 of the fourth layer L4 is composed of the surrounding portion R4 and the first lead conductor 51. The insulating layer IL4 of the fourth layer L4 is provided with a via conductor V connecting the coil conductor layer CC4 and the coil conductor layer CC5. 4y .

[0051] The coil conductor layer CC5 of the fifth layer L5 is composed of the surrounding portion R5 and the second lead conductor 52. The insulating layer IL5 of the fifth layer L5 is provided with a via conductor V connecting the coil conductor layer CC5 and the coil conductor layer CC6. 5x and V 5y .

[0052] The coil conductor layer CC6 of the sixth layer L6 is composed of the surrounding portion R6. The insulating layer IL6 of the sixth layer L6 is provided with a via conductor V connecting the coil conductor layer CC6 and the coil conductor layer CC7. 6x and V 6y .

[0053] The coil conductor layer CC7 of the seventh layer L7 is composed of the surrounding portion R7. The insulating layer IL7 of the seventh layer L7 is provided with a via conductor V connecting the coil conductor layer CC7 and the coil conductor layer CC8. 7x and V 7y .

[0054] The coil conductor layer CC8 of the eighth layer L8 is composed of a surround portion R8 and a second lead conductor 52 .

[0055] Hereinafter, the surrounding portions R1 , R2 , R3 , R4 , R5 , R6 , R7 , and R8 are also collectively referred to as the surrounding portion R.

[0056] The surrounding portion R constitutes a surrounding part of the coil 30A when viewed from the coil axial direction (here, the height direction T).

[0057] Next, the conductor V 1x 、V 1y 、V 2x 、V 2y 、V 3x 、V 3y 、V 4y 、V 5x 、V 5y 、V 6x 、V 6y 、V 7x and V 7y They are also referred to as via conductors V.

[0058] The via conductor V is provided so as to penetrate the insulating layer IL in the stacking direction (here, the height direction T).

[0059] A pad connected to the via conductor V may be provided on the main surface of the insulating layer IL. In this case, the size of the pad may be slightly larger than the line width of the coil conductor layer CC excluding the pad.

[0060] Examples of the constituent material of each coil conductor layer CC (including pads) and each via conductor V include Ag, Au, Cu, Pd, Ni, Al, and alloys containing at least one of these metals.

[0061] If you will Figure 3 When the insulating layers IL configured as shown are stacked in the height direction T, the coil conductor layers CC are electrically connected via the via conductors V. As a result, Figure 2 As shown, a solenoid-shaped coil 30A having a coil axis extending in the height direction T is formed in the laminate 10A.

[0062] Although Figure 3 Although not shown, the laminate 10A preferably includes one or more insulating layers IL on the first principal surface 13 side that are not provided with the coil conductor layer CC. Similarly, the laminate 10A preferably includes one or more insulating layers IL on the second principal surface 14 side that are not provided with the coil conductor layer CC. This also applies to the following embodiments.

[0063] In the laminated inductor of the present invention, the plurality of coil conductor layers includes M+N first coil conductor layers continuous in the stacking direction (here, the height direction T). M and N are natural numbers. Each of the first coil conductor layers includes a first parallel portion, and the first parallel portions of adjacent first coil conductor layers in the stacking direction are connected in parallel via at least two via conductors.

[0064] exist Figure 3In the multilayer inductor 1A shown in FIG. 1 , four coil conductor layers CC1 , CC2 , CC3 , and CC4 constitute the first coil conductor layer 41 . Figure 3 In the multilayer inductor 1A shown, M+N=4.

[0065] In the multilayer inductor 1A, the coil conductor layers CC1 , CC2 , CC3 , and CC4 respectively include first parallel portions P11 , P12 , P13 , and P14 . Hereinafter, the first parallel portions are also referred to as P1 .

[0066] The first parallel portion P11 of the coil conductor layer CC1 and the first parallel portion P12 of the coil conductor layer CC2 are connected via the via conductor V 1x and V 1y Similarly, the first parallel portion P12 of the coil conductor layer CC2 and the first parallel portion P13 of the coil conductor layer CC3 are connected via the via conductor V 2x and V 2y Furthermore, the first parallel portion P13 of the coil conductor layer CC3 and the first parallel portion P14 of the coil conductor layer CC4 are connected via the via conductor V 3x and V 3y Connect in parallel.

[0067] In the multilayer inductor 1A, the entire surround portion R1 of the coil conductor layer CC1 forms a first parallel portion P11. Similarly, the entire surround portion R2 of the coil conductor layer CC2 forms a first parallel portion P12. Furthermore, the entire surround portion R3 of the coil conductor layer CC3 forms a first parallel portion P13. Furthermore, the entire surround portion R4 of the coil conductor layer CC4 forms a first parallel portion P14.

[0068] In the stacked inductor 1A, only the two ends of the first parallel portion P1 are connected to the adjacent first parallel portion P1 via the conductive via conductors V. However, the first parallel portion P1 may also be connected to the adjacent first parallel portion P1 via the conductive via conductors other than the two ends. In this case, the first parallel portions P1 of adjacent first coil conductor layers 41 are connected to each other via three or more conductive via conductors. In this manner, the first parallel portions P1 of adjacent first coil conductor layers 41 may be connected in parallel via at least two conductive via conductors. As in the stacked inductor 1A, the first parallel portions P1 of adjacent first coil conductor layers 41 may be connected in parallel via two conductive via conductors.

[0069] Figure 4 It is a perspective representation in the width direction Figure 1 Figure 1 shows a stacked inductor.

[0070] The M layer in the first coil conductor layer 41 is a first lead layer 41M having a first lead conductor 51 connected to the first external electrode 21. Figure 3 and Figure 4 As shown, in the multilayer inductor 1A, two layers, namely the coil conductor layer CC1 and the coil conductor layer CC4, constitute the first lead layer 41M. That is, in the multilayer inductor 1A, M=2.

[0071] The N layer in the first coil conductor layer 41 is a first non-lead layer 41N that does not have the first lead conductor 51 connected to the first external electrode 21. Figure 3 and Figure 4 As shown, in the multilayer inductor 1A, two layers, namely the coil conductor layer CC2 and the coil conductor layer CC3, constitute the first non-lead layer 41N. That is, in the multilayer inductor 1A, N=2.

[0072] In addition, if Figure 4 As shown, practically no boundaries are visible between adjacent insulating layers IL.

[0073] Hereinafter, the effects of the first coil conductor layer 41 including the first non-lead layer 41N will be described.

[0074] When manufacturing a stacked inductor, methods such as press cutting and cutting with a cutter may include a step of cutting a stacked body block. Below, the manufacturing process of a stacked inductor 1A is described using an example in which a step of cutting a stacked body block along the height direction T so that the first end face 11 of the stacked body 10A forms a cut surface. When cutting a stacked body block, stress is generated in the direction of entry of the cutter. However, because the first lead conductors 51 contain metal components such as Ag, the first lead conductors 51 have a higher elastic modulus and smaller fracture deformation than the insulating layer IL made of a ferrite material, etc. Therefore, when there are many first lead conductors 51 on the cut surface, the stress generated in the direction of entry of the cutter increases the risk of structural defects such as cracks forming in the first lead conductors 51 themselves or at the interface between the first lead conductors 51 and the insulating layer IL.

[0075] like Figure 3 and Figure 4 As shown, in the laminated inductor 1A, two of the four first coil conductor layers 41 serve as first lead layers 41M, and two serve as first non-lead layers 41N. On the other hand, in the laminated inductor 101A of the comparative example described later, four of the four first coil conductor layers 41 serve as first lead layers 41M. Compared to the laminated inductor 101A of the comparative example, the number of first lead conductors 51 in the direction of the cutting blade's travel in the laminated inductor 1A is smaller. This reduces the risk of structural defects such as cracks in the laminated inductor 1A caused by stress generated in the direction of the cutting blade's entry. Consequently, in the laminated inductor 1A, reliability degradation due to structural defects such as cracks is suppressed.

[0076] Furthermore, in the laminated inductor 1A, compared to the laminated inductor 101A of the comparative example, the provision of the first non-lead layer 41N can reduce the number of overlaps of the first lead conductors 51 in the lamination direction (here, the height direction T), thereby improving the impedance of the laminated inductor 1A.

[0077] In the laminated inductor of the present invention, M is preferably a natural number greater than 2, and at least one first non-lead layer 41N is present between at least one set of first lead layers 41M in the stacking direction. Figure 3 and Figure 4 As shown, in a laminated inductor 1A, M is 2, and coil conductor layers CC2 and CC3, serving as first non-lead layers 41N, are located between coil conductor layers CC1 and CC4, serving as first lead layers 41M. The presence of at least one first non-lead layer 41N between at least one set of first lead layers 41M in the stacking direction allows for the interposition of multiple insulating layers IL, made of, for example, ferrite with a low elastic modulus and a large fracture strain, between the first lead layers 41M. This reduces stress concentration on the first lead conductors 51 during the process of cutting the laminated block, further reducing the risk of structural defects such as cracks in the laminated inductor 1A.

[0078] In the laminated inductor of the present invention, it is preferred that M+N is a natural number greater than or equal to 3, and the first lead layer 41M is not continuous with two or more layers in the lamination direction. Figure 3 and Figure 4 As shown, in the laminated inductor 1A, M+N equals 4, and the coil conductor layers CC1 and CC4, serving as first lead layers 41M, are discontinuous in the stacking direction. If the first lead layers 41M are discontinuous in the stacking direction by two or more layers, first non-lead layers 41N are interposed between the first lead layers 41M. Consequently, multiple insulating layers IL, made of, for example, ferrite with a low elastic modulus and a large fracture deformation, are interposed between the first lead layers 41M. This suppresses stress concentration on the first lead conductors 51 during the process of cutting the laminated block, further reducing the risk of structural defects such as cracks in the laminated inductor 1A.

[0079] like Figure 3 and Figure 4 As shown, in the laminated inductor 1A, M=2 and N=2, and two first non-lead layers 41N are continuously provided in the lamination direction between two first lead layers 41M.

[0080] like Figure 3 As in the illustrated laminated inductor 1A, when viewed in the stacking direction, the orientation and shape of the portion forming the current path in the surrounding portion R of the first lead layer 41M are preferably the same as the orientation and shape of the portion forming the current path in the surrounding portion R of the first non-lead layer 41N.

[0081] When viewed from the stacking direction, if the orientation and shape of the portion of the current path in the surrounding portion R of the first lead layer 41M is the same as the orientation and shape of the portion of the current path in the surrounding portion R of the first non-lead layer 41N, the magnetic flux of the coil can be prevented from being blocked, thereby most effectively improving the impedance. If the orientation or shape of the portion of the current path in the surrounding portion R of the first lead layer 41M is different from the orientation or shape of the portion of the current path in the surrounding portion R of the first non-lead layer 41N, there is a concern that the magnetic flux of the coil will be blocked or canceled out in the portions of the surrounding portions R that have different shapes or orientations. Therefore, there is a concern that the impedance of the stacked inductor will be reduced.

[0082] Furthermore, when viewed from the stacking direction, if the orientation and shape of the portion forming the current path in the surrounding portion R of the first lead layer 41M is identical to the orientation and shape of the portion forming the current path in the surrounding portion R of the first non-lead layer 41N, differences in current density in the conductors of each first parallel portion P1 can be avoided, thereby suppressing degradation of the laminated inductor 1A over long-term use. If the orientation or shape of the portion forming the current path in the surrounding portion R of the first lead layer 41M differs from the orientation or shape of the portion forming the current path in the surrounding portion R of the first non-lead layer 41N, the ease of current flow in each first parallel portion P1 may differ. In this case, a large amount of current selectively flows in the first parallel portion P1, which is the path most likely to flow current. This accelerates degradation of the path most likely to flow current, potentially leading to degradation of the laminated inductor.

[0083] The portion of the surrounding portion R of the first extraction layer 41M that constitutes the current path means the portion of the surrounding portion R of the first extraction layer 41M excluding the dummy electrodes where current does not flow. Similarly, the portion of the surrounding portion R of the first non-extraction layer 41N that constitutes the current path means the portion of the surrounding portion R of the first non-extraction layer 41N excluding the dummy electrodes where current does not flow. Figure 3 As shown, since the laminated inductor 1A does not have a dummy electrode where current does not flow, the entire surrounding portion R of the first lead layer 41M and the entire surrounding portion R of the first non-lead layer 41N constitute a current path.

[0084] In the laminated inductor 1A, the orientation and shape of the surrounding portion R of the first lead layer 41M are identical to those of the surrounding portion R of the first non-lead layer 41N when viewed in the stacking direction. In the laminated inductor 1A, the entire surrounding portion R of the first lead layer 41M overlaps the entire surrounding portion R of the first non-lead layer 41N when viewed in the stacking direction.

[0085] Preferably, in at least one layer of the first lead layer 41M, the width of the portion of the first lead conductor 51 that contacts the first external electrode 21 is larger than the width of the first parallel portion P1. Figure 3 As shown, in the multilayer inductor 1A, in the coil conductor layer CC1 serving as the first lead layer 41M, the width A1 of the portion of the first lead conductor 51 in contact with the first external electrode 21 is greater than the width B1 of the first parallel portion P11. Furthermore, in the coil conductor layer CC4 serving as the first lead layer 41M, the width A4 of the portion of the first lead conductor 51 in contact with the first external electrode 21 is greater than the width B4 of the first parallel portion P14. As in the multilayer inductor 1A, it is preferable that the width of the portion of the first lead conductor 51 in contact with the first external electrode 21 is greater than the width of the first parallel portion P1 in all first lead layers 41M.

[0086] If the width of the portion of the first lead conductor 51 that contacts the first external electrode 21 is greater than the width of the first parallel portion P1, for example, when the laminate block is cut along the height direction T so that the first end face 11 of the laminate 10A forms the cut surface, the area of ​​the first lead conductor 51 can be increased in a direction perpendicular to the direction of entry of the cutter. This reduces stress concentration in the first lead conductor 51, further reducing the risk of structural defects such as cracks in the laminated inductor 1A.

[0087] On the other hand, in the laminated inductor 1A, the number of first lead layers 41M is reduced compared to a structure without the first non-lead layer 41N. Therefore, the resistance of the first lead conductor 51 increases by the amount of the first lead layer 41M. Therefore, by making the width of the portion of the first lead conductor 51 that contacts the first external electrode 21 larger than the width of the first parallel portion P1, the increase in resistance of the first lead conductor 51 can be suppressed.

[0088] It is preferable that the total width of the portion of the first lead conductor 51 in the first lead layer 41M that contacts the first external electrode 21 is equal to or greater than the total width of the first parallel portion P1 in the first lead layer 41M and the first non-lead layer 41N. Figure 3As shown, in the multilayer inductor 1A, the sum of the widths A1 of the portion of the first lead conductor 51 in coil conductor layer CC1 that contacts the first external electrode 21 and A4 of the portion of the first lead conductor 51 in coil conductor layer CC4 that contacts the first external electrode 21 equals the sum of the widths of the portion of the first lead conductor 51 in the first lead layer 41M that contacts the first external electrode 21. Furthermore, the sum of the widths B1 to B4 of the first parallel portions P11, P12, P13, and P14 of the coil conductor layers CC1, CC2, CC3, and CC4 equals the sum of the widths of the first parallel portion P1 in the first lead layer 41M and the first non-lead layer 41N. In the multilayer inductor 1A, the sum of the widths of the portion of the first lead conductor 51 in the first lead layer 41M that contacts the first external electrode 21 is greater than the sum of the widths of the first parallel portion P1 in the first lead layer 41M and the first non-lead layer 41N. The total width of the portion of the first lead conductor 51 in the first lead layer 41M that contacts the first external electrode 21 may be equal to the total width of the first parallel portion P1 in the first lead layer 41M and the first non-lead layer 41N.

[0089] If the total width of the portion of the first lead conductor 51 in the first lead layer 41M that contacts the first external electrode 21 is equal to or greater than the total width of the first parallel portion P1 in the first lead layer 41M and the first non-lead layer 41N, it is possible to suppress the current density in the first lead conductor 51 from becoming higher than the current density in the surrounding portion R. Therefore, the occurrence of electromigration in the first lead conductor 51 can be suppressed.

[0090] In the multilayer inductor 1A, the width of the first lead conductor 51 is larger at the portion in contact with the first external electrode 21 than at the portion in contact with the surrounding portion R1. The width of the first lead conductor 51 may be constant.

[0091] In the first lead layer 41M, the first lead conductor 51 and the first parallel portion P1 may also be directly connected. Figure 3 As shown, in the multilayer inductor 1A, the first lead conductor 51 is directly connected to the first parallel portion P11 in the coil conductor layer CC1 serving as the first lead layer 41M. Similarly, the first lead conductor 51 is directly connected to the first parallel portion P14 in the coil conductor layer CC4 serving as the first lead layer 41M.

[0092] In the first lead layer 41M, the portion of the first lead conductor 51 connecting the first external electrode 21 and the conducting conductor V located at a position where the path length to the first external electrode 21 is shortest may be formed of a linear shape except for the portion of the first lead conductor 51 in contact with the first external electrode 21.

[0093] For example, in the coil conductor layer CC1 serving as the first lead layer 41M, the via conductor V 1x The via conductor V is located at the position where the path length to the first external electrode 21 is the shortest. In the coil conductor layer CC1, the width of the portion of the first lead conductor 51 that contacts the first external electrode 21 is widened. In this case, the first external electrode 21 and the via conductor V 1x In the part between Figure 3 The portion of width indicated by B1 in the coil conductor layer CC1 is also formed of a straight line. Therefore, in the coil conductor layer CC1, it can be said that the first external electrode 21 and the via conductor V 1x The portion between them is formed into a linear shape except for the portion in contact with the first external electrode 21 .

[0094] The portion of the surrounding portion R of the first non-lead layer 41N that constitutes the current path may be constituted only by the first parallel portion P1. Alternatively, the entire surrounding portion R of the first non-lead layer 41N may be constituted only by the first parallel portion P1. Figure 3 As shown, in the laminated inductor 1A, in the coil conductor layer CC2, which is the first non-lead layer 41N, the entire surrounding portion R2 is composed solely of the first parallel portion P12. Similarly, in the coil conductor layer CC3, which is the first non-lead layer 41N, the entire surrounding portion R3 is composed solely of the first parallel portion P13.

[0095] In the laminated inductor of the present invention, the plurality of coil conductor layers may have K+L layers in the lamination direction (in the lamination direction). Figure 3 (in the height direction T) represents a second coil conductor layer continuous in the height direction. K and L are natural numbers. Each second coil conductor layer has a second parallel portion, and the second parallel portions of adjacent second coil conductor layers in the stacking direction are connected in parallel via at least two via conductors.

[0096] exist Figure 3 In the multilayer inductor 1A shown in FIG. 1 , the four coil conductor layers CC5 , CC6 , CC7 , and CC8 constitute the second coil conductor layer 42 . Figure 3 In the multilayer inductor 1A shown, K+L=4.

[0097] In the multilayer inductor 1A, the coil conductor layers CC5, CC6, CC7, and CC8 include second parallel portions P25, P26, P27, and P28, respectively. Hereinafter, the second parallel portions are also referred to as P2.

[0098] The second parallel portion P25 of the coil conductor layer CC5 and the second parallel portion P26 of the coil conductor layer CC6 are connected via the via conductor V 5x and the conducting conductor V 5ySimilarly, the second parallel portion P26 of the coil conductor layer CC6 and the second parallel portion P27 of the coil conductor layer CC7 are connected via the via conductor V 6x and the conducting conductor V 6y Furthermore, the second parallel portion P27 of the coil conductor layer CC7 and the second parallel portion P28 of the coil conductor layer CC8 are connected via the via conductor V 7x and the conducting conductor V 7y Connect in parallel.

[0099] In the multilayer inductor 1A, the entire surround portion R5 of the coil conductor layer CC5 forms the second parallel portion P25. Similarly, the entire surround portion R6 of the coil conductor layer CC6 forms the second parallel portion P26. Furthermore, the entire surround portion R7 of the coil conductor layer CC7 forms the second parallel portion P27. Furthermore, the entire surround portion R8 of the coil conductor layer CC8 forms the second parallel portion P28.

[0100] In the stacked inductor 1A, only the two ends of the second parallel portion P2 are connected to the adjacent second parallel portion P2 via the via conductors V. However, the second parallel portion P2 may also be connected to the adjacent second parallel portion P2 via the via conductors except for the two ends. In this case, the second parallel portions P2 of adjacent second coil conductor layers 42 are connected to each other via three or more via conductors. In this way, the second parallel portions P2 of adjacent second coil conductor layers 42 may be connected in parallel via at least two via conductors. As in the stacked inductor 1A, the second parallel portions P2 of adjacent second coil conductor layers 42 may also be connected in parallel via two via conductors.

[0101] The K layer in the second coil conductor layer 42 is a second lead layer 42K having a second lead conductor 52 connected to the second external electrode 22. Figure 3 and Figure 4 As shown, in the multilayer inductor 1A, two layers, the coil conductor layer CC5 and the coil conductor layer CC8, constitute the second lead layer 42K. That is, in the multilayer inductor 1A, K=2.

[0102] The L layer in the second coil conductor layer 42 is a second non-lead layer 42L that does not have the second lead conductor 52 connected to the second external electrode 22. Figure 3 and Figure 4 As shown, in the multilayer inductor 1A, two layers, namely the coil conductor layer CC6 and the coil conductor layer CC7, constitute the second non-lead layer 42L. That is, in the multilayer inductor 1A, L=2.

[0103] If the second coil conductor layer 42 has a second non-lead layer 42L, then in the process of manufacturing the stacked inductor 1A, for example, in the case of a process including cutting the stacked body block along the height direction T so that the second end face 12 of the stacked body 10A becomes a cut surface, the risk of structural defects such as cracks in the stacked inductor 1A can be reduced.

[0104] In the multilayer inductor 1A, the four coil conductor layers CC from the second principal surface 14 side of the multilayer body 10A constitute the first coil conductor layer 41, and the four coil conductor layers CC from the first principal surface 13 side of the multilayer body 10A constitute the second coil conductor layer 42. The second coil conductor layer 42 is provided on the principal surface opposite to the first coil conductor layer 41 and has the same structure as the first coil conductor layer 41, except that the lead conductor is connected to the second external electrode 22.

[0105] The following, Figures 1 to 4 An example of a method for manufacturing the laminated inductor 1A shown in FIG.

[0106] <Magnetic Material Production Process>

[0107] First, Fe 2 O 3 , ZnO, CuO, and NiO are weighed so as to achieve a predetermined ratio.

[0108] Next, these weighed materials, pure water, and PSZ (partially stabilized zirconia) media are placed in a ball mill, mixed, and then pulverized. The mixing and pulverization time is, for example, 4 hours to 8 hours.

[0109] The obtained pulverized product is then dried and then calcined. The calcination temperature is, for example, 700° C. to 800° C. The calcination time is, for example, 2 hours to 5 hours.

[0110] In this manner, a powdered magnetic material, more specifically, a powdered magnetic ferrite material is produced.

[0111] As the ferrite material, for example, a Ni—Cu—Zn-based ferrite material is used.

[0112] For example, when the total amount is set to 100 mol%, the Ni-Cu-Zn ferrite material includes: Fe calculated as Fe2O3 in an amount of 40 mol% or more and 49.5 mol% or less, Zn calculated as ZnO in an amount of 2 mol% or more and 35 mol% or less, Cu calculated as CuO in an amount of 6 mol% or more and 13 mol% or less, and Ni calculated as NiO in an amount of 10 mol% or more and 45 mol% or less.

[0113] Ni-Cu-Zn based ferrite materials may further contain additives such as Co, Bi, Sn, and Mn.

[0114] The Ni—Cu—Zn-based ferrite material may further contain unavoidable impurities.

[0115] Green Sheet Production Process

[0116] First, a magnetic material, an organic binder such as a polyvinyl butyral resin, an organic solvent such as ethanol or toluene, and a plasticizer are placed in a ball mill together with a PSZ medium, mixed, and then pulverized to prepare a slurry.

[0117] Next, the slurry is formed into a sheet of a predetermined thickness using a doctor blade method or the like, and then punched into a predetermined shape to produce a green sheet. The thickness of the green sheet is, for example, 20 μm to 30 μm inclusive, and the shape of the green sheet is, for example, rectangular.

[0118] As the material of the green sheet, a non-magnetic material such as a borosilicate glass material may be used instead of a magnetic material, or a mixed material of a magnetic material and a non-magnetic material may be used.

[0119] <Conductor Pattern Formation Process>

[0120] First, via holes are formed by irradiating predetermined portions of a green sheet with laser light.

[0121] Next, a conductive paste such as Ag paste is filled into the via holes and applied to the surface of the green sheet by screen printing or the like. Thus, a conductive pattern for a via conductor is formed in the via hole of the green sheet, and a conductor pattern for a coil conductor connected to the conductor pattern for the via conductor is formed on the surface. In this way, a coil sheet having a conductor pattern for a coil conductor and a conductor pattern for a via conductor formed on the green sheet is produced. Figure 3 The coil conductor layer CC (including the first lead conductors 51 and 52) shown in FIG. Figure 3 The via conductor V shown is a conductor pattern.

[0122] <Laminated Block Production Process>

[0123] By pressing the coil sheet into Figure 3 After stacking in the stacking direction (here, from the negative direction to the positive direction of the height direction T) in the order of, heat pressing is performed to produce a stacked body block.

[0124] <Laminate and Coil Production Process>

[0125] First, the laminated body block is cut into predetermined sizes by press cutting, dicing, or the like, thereby producing individual chips.

[0126] Next, the singulated chips are fired at a temperature of, for example, 900° C. to 920° C., and for a time of, for example, 2 hours to 4 hours.

[0127] When the individual chips are fired, the green sheets of the coil sheets serve as insulating layers.

[0128] When the singulated chips are fired, the coil conductor pattern and the via conductor pattern become coil conductors and via conductors, respectively. As a result, a coil is produced in which a plurality of coil conductors stacked together with the insulating layer are electrically connected via the via conductors.

[0129] As described above, a laminated body is produced in which a plurality of insulating layers are laminated in the lamination direction and the coil is provided therein.

[0130] Corners and ridges may be rounded by, for example, barrel polishing the laminate.

[0131] External Electrode Formation Process

[0132] First, a conductive paste such as a paste containing Ag and glass frit is applied to the end surface of the outer surface of the laminate where the coil is led out, thereby forming a conductive paste layer.

[0133] Next, the conductive paste layer is fired to form a base electrode of the external electrode. The firing temperature is, for example, 800° C. to 820° C. The thickness of the base electrode is, for example, 5 μm.

[0134] Then, a Ni-plated electrode and a Sn-plated electrode are sequentially formed on the surface of the base electrode by electrolytic plating, etc. Thus, an external electrode including the base electrode, the Ni-plated electrode, and the Sn-plated electrode in this order is formed.

[0135] Through the above process, the multilayer inductor 1A is manufactured.

[0136] The dimensions of the multilayer inductor 1A are, for example, 2.0 mm in the longitudinal direction L, 1.25 mm in the width direction W, and 1.25 mm in the height direction T.

[0137] Figure 5 This is a view showing a laminated inductor of a comparative example in a perspective manner in the height direction.

[0138] Figure 6 This is a view showing a laminated inductor of a comparative example in a perspective manner in the width direction.

[0139] like Figure 5 As shown, in a laminated inductor 101A of the comparative example, a laminate 10A includes a coil 30A therein.

[0140] The coil 30A includes a first lead conductor 51 and a second lead conductor 52. The coil 30A is connected to the first external electrode 21 via the first lead conductor 51. The coil 30A is connected to the second external electrode 22 via the second lead conductor 52.

[0141] like Figure 6 As shown, in the multilayer inductor 101A of the comparative example, the coil conductor layers CC1, CC2, CC3, and CC4 are all first lead layers 41M having first lead conductors 51. Furthermore, the coil conductor layers CC5, CC6, CC7, and CC8 are all second lead layers 42K having second lead conductors 52. The multilayer inductor 101A of the comparative example has the same structure as the multilayer inductor 1A, except that the number of first lead conductors 51 and the number of second lead conductors 52 in the coil 30A are different.

[0142] In the comparative example laminated inductor 101A, four layers of first lead conductors 51 are continuously stacked on the first end surface 11 of the laminate 10A. The manufacturing method of the comparative example laminated inductor 101A may include a step of cutting the laminate block along the height direction T so that the first end surface 11 of the laminate 10A forms the cut surface. In this case, the comparative example laminated inductor 101A contains more metal components, such as Ag, in the material of the first lead conductors 51 in the direction of cutting than the laminated inductor 1A. Metal components such as Ag have a higher elastic modulus and smaller fracture deformation than the ferrite material constituting the insulating layer IL. Therefore, in the laminated inductor 101A whose cut surface contains a high amount of metal components, such as Ag, there is a higher risk of structural defects such as cracks due to stress generated in the direction of the cutting blade.

[0143] Figure 7 It is along Figure 5 FIG1 is a schematic diagram showing an enlarged view of the first lead conductor in a cross section along line VII-VII in FIG1 .

[0144] exist Figure 7 In the example shown, a crack CR is generated which passes through the interface between the first lead conductor 51 and the insulating layer IL. In addition, in the laminated inductor 101A, there is also a case where not only cracks Figure 7 Cracks CR such as those that pass through the interface between the first lead conductor 51 and the insulating layer IL may also cause the first lead conductor 51 itself to break. If structural defects such as cracks CR occur in the laminated inductor 101A, the risk of wire breakage increases during use of the laminated inductor 101A, thereby reducing the reliability of the laminated inductor 101A.

[0145] [Second embodiment]

[0146] In the laminated inductor according to the second embodiment of the present invention, the first lead layers and the first non-lead layers are alternately provided in the stacking direction.

[0147] Figure 8 This is an exploded plan view schematically showing an example of a laminated inductor according to the second embodiment of the present invention.

[0148] Figure 8 The illustrated multilayer inductor 1B has a structure in which the coil conductor layer CC3 of the third layer L3 and the coil conductor layer CC4 of the fourth layer L4 are replaced, and the coil conductor layer CC5 of the fifth layer L5 and the coil conductor layer CC6 of the sixth layer L6 are replaced. Except for the above-mentioned points, the multilayer inductor 1B has the same structure as the multilayer inductor 1A.

[0149] exist Figure 8 In the multilayer inductor 1B shown in FIG. 1 , the four coil conductor layers CC1 , CC2 , CC3 , and CC4 constitute the first coil conductor layer 41 . Figure 8 In the multilayer inductor 1B shown, M+N=4.

[0150] exist Figure 8 In the multilayer inductor 1B shown, two layers, the coil conductor layer CC1 and the coil conductor layer CC3, constitute the first lead layer 41M. That is, in the multilayer inductor 1B, M=2.

[0151] exist Figure 8 In the multilayer inductor 1B shown, two layers, the coil conductor layer CC2 and the coil conductor layer CC4, constitute the first non-lead layer 41N. That is, in the multilayer inductor 1B, N=2.

[0152] exist Figure 8 In the illustrated laminated inductor 1B, first lead layers 41M and first non-lead layers 41N are arranged alternately in the stacking direction (here, the height direction T). Alternating the first lead layers 41M and first non-lead layers 41N in the stacking direction prevents the first lead layers 41M from being continuous in the stacking direction. This further reduces the risk of structural defects such as cracks in the laminated inductor 1B.

[0153] When the first lead layers 41M and the first non-lead layers 41N are alternately arranged in the stacking direction, M+N is a natural number greater than or equal to 3. Although not shown in the figure, when M+N is 3, one first non-lead layer 41N may be provided between a set of first lead layers 41M, or one first lead layer 41M may be provided between a set of first non-lead layers 41N.

[0154] You can also Figure 8As in the laminated inductor 1B shown in FIG. , multiple first lead layers 41M are provided, with first lead layers 41M and first non-lead layers 41N arranged alternately in the stacking direction. In this case, first non-lead layers 41N are interposed between each of the multiple first lead layers 41M. Consequently, multiple insulating layers IL composed of, for example, ferrite, which has a low elastic modulus and a large fracture deformation, are sandwiched between the first lead layers 41M. This suppresses stress concentration on the first lead conductors 51 during the process of cutting the laminated block, further reducing the risk of structural defects such as cracks in the laminated inductor 1B.

[0155] exist Figure 8 In the illustrated laminated inductor 1B, second lead layers 42K and second non-lead layers 42L are alternately arranged in the stacking direction. By alternating the second lead layers 42K and the second non-lead layers 42L in the stacking direction, the second lead layers 42K are no longer continuous in the stacking direction. This further reduces the risk of structural defects such as cracks in the laminated inductor 1B.

[0156] [Third embodiment]

[0157] In the laminated inductor according to the third embodiment of the present invention, there is one first lead layer and one first non-lead layer.

[0158] Figure 9 This is an exploded plan view schematically showing an example of a laminated inductor according to the third embodiment of the present invention.

[0159] Figure 9 The illustrated multilayer inductor 1C is constructed by removing the coil conductor layer CC3 of the third layer L3, the coil conductor layer CC4 of the fourth layer L4, the coil conductor layer CC5 of the fifth layer L5, and the coil conductor layer CC6 of the sixth layer L6 from the multilayer inductor 1A. Except for the above-mentioned points, the multilayer inductor 1C has the same structure as the multilayer inductor 1A.

[0160] exist Figure 9 In the multilayer inductor 1C shown, the two layers of coil conductor layer CC1 and coil conductor layer CC2 constitute the first coil conductor layer 41. Figure 9 In the illustrated laminated inductor 1C, M+N=2.

[0161] exist Figure 9 In the multilayer inductor 1C shown, the coil conductor layer CC1 serves as the first lead layer 41M. That is, in the multilayer inductor 1C, M=1.

[0162] exist Figure 9 In the illustrated multilayer inductor 1C, the coil conductor layer CC2 serves as the first non-lead layer 41N. That is, in the multilayer inductor 1C, N=1.

[0163] exist Figure 9 In the multilayer inductor 1C shown, the coil conductor layer CC3 and the coil conductor layer CC4 constitute the second coil conductor layer 42. Figure 9 In the stacked inductor 1C shown, K+L=2.

[0164] exist Figure 9 In the multilayer inductor 1C shown, the coil conductor layer CC4 serves as the second lead layer 42K. That is, in the multilayer inductor 1C, K=1.

[0165] exist Figure 9 In the multilayer inductor 1C shown, the coil conductor layer CC3 serves as the second non-lead layer 42L. That is, in the multilayer inductor 1C, L=1.

[0166] [Fourth embodiment]

[0167] In the multilayer inductor according to the fourth embodiment of the present invention, parts of the coil conductor layers present between the first coil conductor layer and the second coil conductor layer are connected in parallel.

[0168] Figure 10 It is an exploded plan view schematically showing an example of a laminated inductor according to a fourth embodiment of the present invention.

[0169] exist Figure 10 In the multilayer inductor 1D shown, the coil conductor layers CC1, CC2, CC3, CC4, CC5, CC6, CC7, and CC8 are connected via the via conductors V 1x 、V 1y 、V 2x 、V 2y 、V 3x 、V 3y 、V 3z 、V 4x 、V 4y 、V 4z 、V 5x 、V 5y 、V 5z 、V 6x 、V 6y 、V 7x and V 7y Electrical connection.

[0170] exist Figure 10 In the multilayer inductor 1D shown, the coil conductor layer CC4 of the fourth layer L4 is located between the first coil conductor layer and the second coil conductor layer. A portion of the coil conductor layer CC4 is connected in parallel to the coil conductor layer adjacent to the layer stacking direction.

[0171] A portion of the coil conductor layer CC4 is connected via the via conductor V 3x 、V 3y and V 3z It is connected in parallel with a part of the coil conductor layer CC3 of the third layer L3. In addition, a part of the coil conductor layer CC4 is connected via the via conductor V 4x 、V 4y and V 4z It is connected in parallel with a part of the coil conductor layer CC5 of the fifth layer L5.

[0172] In the laminated inductor 1D, the coil conductor layers between the first and second coil conductor layers are connected in parallel, thereby reducing DC resistance. Furthermore, since only a portion of the coil conductor layers between the first and second coil conductor layers are connected in parallel, the number of via conductors that overlap in the stacking direction is reduced. Consequently, cracks that may form during firing of the laminated inductor 1D due to the overlapping of multiple via conductors in the stacking direction are suppressed.

[0173] [Fifth embodiment]

[0174] In the multilayer inductor according to the fifth embodiment of the present invention, the coil conductor layers between the first coil conductor layer and the second coil conductor layer are connected in series.

[0175] Figure 11 It is an exploded plan view schematically showing an example of a laminated inductor according to a fifth embodiment of the present invention.

[0176] exist Figure 11 In the multilayer inductor 1E shown, the coil conductor layers CC1, CC2, CC3, CC4, CC5, CC6, CC7, CC8, and CC9 are connected via the via conductors V 1x 、V 1y 、V 2x 、V 2y 、V 3x 、V 4x 、V 5x 、V 6x 、V 7x 、V 7y 、V 8x and V 8y Electrical connection.

[0177] exist Figure 11 In the multilayer inductor 1E shown, coil conductor layer CC4 of fourth layer L4, coil conductor layer CC5 of fifth layer L5, and coil conductor layer CC6 of sixth layer L6 are located between the first and second coil conductor layers. Coil conductor layers CC4, CC5, and CC6 are connected in series.

[0178] exist Figure 11 In the illustrated stacked inductor 1E, the first coil conductor layer has a parallel portion, which reduces current concentration in the first coil conductor layer. Furthermore, the first coil conductor layer includes a first non-lead layer, which reduces stress concentration on the first lead conductor 51 during the process of cutting the stacked body block. Stacked inductor 1E is an example of a stacked inductor that achieves the above-mentioned effects and connects the coil conductor layers between the first and second coil conductor layers in series.

[0179] The laminated inductor of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made to the structure, manufacturing conditions, etc. of the laminated inductor within the scope of the present invention.

[0180] In the multilayer inductor of the present invention, M and N may be the same or different.

[0181] When the laminated inductor of the present invention includes a second coil conductor layer, K and L may be the same or different. Furthermore, M and K may be the same or different. Similarly, N and L may be the same or different.

[0182] When the laminated inductor of the present invention includes a second coil conductor layer, there may be no other coil conductor layer between the first and second coil conductor layers, as in the first to third embodiments, or there may be another coil conductor layer between the first and second coil conductor layers, as in the fourth and fifth embodiments. For example, when the third coil conductor layer is present between the first and second coil conductor layers, the structure of the third coil conductor layer is not particularly limited.

[0183] The following contents are disclosed in this specification.

[0184] <1> A laminated inductor comprising:

[0185] a laminated body having a plurality of insulating layers laminated in a lamination direction and having a coil therein; and

[0186] The first external electrode and the second external electrode are provided on the outer surface of the stack and are electrically connected to the coil.

[0187] The coil is formed by electrically connecting a plurality of coil conductor layers, wherein the plurality of coil conductor layers are stacked together with the insulating layer in the stacking direction.

[0188] The plurality of coil conductor layers include M+N layers of first coil conductor layers continuous in the stacking direction, where M and N are natural numbers.

[0189] The first coil conductor layers each have a first parallel portion.

[0190] The first parallel portions of the first coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors.

[0191] The M layer of the first coil conductor layer is a first lead layer having a first lead conductor, and the N layer is a first non-lead layer not having the first lead conductor, wherein the first lead conductor is connected to the first external electrode.

[0192] M is a natural number greater than 2,

[0193] At least one first non-leading layer exists between at least one group of the first leading layers in the stacking direction.

[0194] <2> A laminated inductor comprising:

[0195] a laminated body having a plurality of insulating layers laminated in a lamination direction and having a coil therein; and

[0196] The first external electrode and the second external electrode are provided on the outer surface of the stack and are electrically connected to the coil.

[0197] The coil is formed by electrically connecting a plurality of coil conductor layers, wherein the plurality of coil conductor layers are stacked together with the insulating layer in the stacking direction.

[0198] The plurality of coil conductor layers include M+N layers of first coil conductor layers continuous in the stacking direction, where M and N are natural numbers.

[0199] The first coil conductor layers each have a first parallel portion.

[0200] The first parallel portions of the first coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors.

[0201] The M layer of the first coil conductor layer is a first lead layer having a first lead conductor, and the N layer is a first non-lead layer not having the first lead conductor, wherein the first lead conductor is connected to the first external electrode.

[0202] When viewed in the stacking direction, the orientation and shape of a portion constituting a current path in the surrounding portion of the first extraction layer are identical to the orientation and shape of a portion constituting a current path in the surrounding portion of the first non-extraction layer.

[0203] <3> The laminated inductor according to <2>, wherein:

[0204] In the first extraction layer, a portion connecting the first external electrode and the via conductor located at a position where the path length to the first external electrode is shortest is formed in a linear shape except for a portion in contact with the first external electrode.

[0205] <4> The laminated inductor according to <2> or <3>, wherein:

[0206] M is a natural number greater than 2,

[0207] At least one first non-leading layer exists between at least one group of the first leading layers in the stacking direction.

[0208] <5> The laminated inductor according to any one of <1> to <4>, wherein

[0209] In at least one layer of the first lead layer, a portion of the first lead conductor in contact with the first external electrode has a width greater than a width of the first parallel portion.

[0210] <6> The laminated inductor according to any one of <1> to <5>, wherein

[0211] The total width of a portion of the first lead conductor in the first lead layer that contacts the first external electrode is equal to or greater than the total width of the first parallel portion in the first lead layer and the first non-lead layer.

[0212] <7> The laminated inductor according to any one of <1> to <6>, wherein

[0213] M+N is a natural number greater than 3,

[0214] The first extraction layer is not continuous with two or more layers in the stacking direction.

[0215] <8> The laminated inductor according to <7>, wherein:

[0216] M+N is a natural number greater than 3,

[0217] The first extraction layers and the first non-extraction layers are alternately arranged in the stacking direction.

[0218] <9> The laminated inductor according to <7>, wherein:

[0219] M=2 and N=2,

[0220] Between the two first lead layers, two first non-lead layers are continuously provided in the stacking direction.

[0221] <10> The laminated inductor according to any one of <1> to <9>, wherein

[0222] In the first lead layer, the first lead conductor and the first parallel portion are directly connected.

[0223] <11> The laminated inductor according to any one of <1> to <10>, wherein

[0224] The portion constituting the current path in the surrounding portion of the first non-extraction layer is constituted by only the parallel portion.

[0225] <12> The laminated inductor according to any one of <1> to <11>, wherein

[0226] The plurality of coil conductor layers include a second coil conductor layer of K+L layers continuous in the stacking direction, wherein K and L are natural numbers.

[0227] The second coil conductor layers each have a second parallel portion.

[0228] The second parallel portions of the second coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors.

[0229] The K layer of the second coil conductor layer is a second lead layer having a second lead conductor connected to the second external electrode, and the L layer is a second non-lead layer not having the second lead conductor.

Claims

1. A stacked inductor comprising: a laminated body having a plurality of insulating layers laminated in a lamination direction and having a coil therein; and The first external electrode and the second external electrode are provided on the outer surface of the stack and are electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductor layers, wherein: The plurality of coil conductor layers are stacked together with the insulating layer in the stacking direction. The plurality of coil conductor layers include M+N layers of first coil conductor layers continuous in the stacking direction, where M and N are natural numbers. The first coil conductor layers each have a first parallel portion. The first parallel portions of the first coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors. The M layer of the first coil conductor layer is a first lead layer having a first lead conductor, and the N layer is a first non-lead layer not having the first lead conductor, wherein the first lead conductor is connected to the first external electrode. M is a natural number greater than 2, At least one first non-leading layer exists between at least one group of the first leading layers in the stacking direction.

2. A stacked inductor comprising: a laminated body having a plurality of insulating layers laminated in a lamination direction and having a coil therein; and The first external electrode and the second external electrode are provided on the outer surface of the stack and are electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductor layers, wherein: The plurality of coil conductor layers are stacked together with the insulating layer in the stacking direction. The plurality of coil conductor layers include M+N layers of first coil conductor layers continuous in the stacking direction, where M and N are natural numbers. The first coil conductor layers each have a first parallel portion. The first parallel portions of the first coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors. The M layer of the first coil conductor layer is a first lead layer having a first lead conductor, and the N layer is a first non-lead layer not having the first lead conductor, wherein the first lead conductor is connected to the first external electrode. When viewed in the stacking direction, the orientation and shape of a portion constituting a current path in the surrounding portion of the first extraction layer are identical to the orientation and shape of a portion constituting a current path in the surrounding portion of the first non-extraction layer.

3. The laminated inductor according to claim 2, wherein: In the first lead layer, a portion of the first lead conductor connecting the first external electrode and the via conductor located at a position where the path length to the first external electrode is shortest is formed in a straight line except for a portion of the first lead conductor in contact with the first external electrode.

4. The laminated inductor according to claim 2 or 3, wherein: M is a natural number greater than 2, At least one first non-leading layer exists between at least one group of the first leading layers in the stacking direction.

5. The laminated inductor according to any one of claims 1 to 4, wherein In at least one layer of the first lead layer, a portion of the first lead conductor in contact with the first external electrode has a width greater than a width of the first parallel portion.

6. The laminated inductor according to any one of claims 1 to 5, wherein The total width of a portion of the first lead conductor in the first lead layer that contacts the first external electrode is equal to or greater than the total width of the first parallel portion in the first lead layer and the first non-lead layer.

7. The laminated inductor according to any one of claims 1 to 6, wherein M+N is a natural number greater than 3, The first extraction layer is not continuous with two or more layers in the stacking direction.

8. The laminated inductor according to claim 7, wherein M+N is a natural number greater than 3, The first extraction layers and the first non-extraction layers are alternately arranged in the stacking direction.

9. The laminated inductor according to claim 7, wherein M=2 and N=2, Between the two first lead layers, two first non-lead layers are continuously provided in the stacking direction.

10. The laminated inductor according to any one of claims 1 to 9, wherein In the first lead layer, the first lead conductor and the first parallel portion are directly connected.

11. The laminated inductor according to any one of claims 1 to 10, wherein The portion constituting the current path in the surrounding portion of the first non-extraction layer is constituted by only the parallel portion.

12. The laminated inductor according to any one of claims 1 to 11, wherein The plurality of coil conductor layers include a second coil conductor layer of K+L layers continuous in the stacking direction, wherein K and L are natural numbers. The second coil conductor layers each have a second parallel portion. The second parallel portions of the second coil conductor layers adjacent to each other in the stacking direction are connected in parallel via at least two via conductors. The K layer of the second coil conductor layer is a second lead layer having a second lead conductor connected to the second external electrode, and the L layer is a second non-lead layer not having the second lead conductor.

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