Lamination coil component

Abstract

To provide a lamination coil component having an excellent high-frequency property.SOLUTION: A lamination coil component comprises: a lamination body having a coil inside; and first and second external electrodes that are electrically connected to the coil. In the coil, a plurality of coil conductors 32 laminated with an insulation layer 31 are connected via a via conductor 33. Each coil conductor 32 contains: a circulation part 34; and a land 35 connected to the via conductor 33. The lamination body includes: first and second end surfaces that face each other in a length direction; first and second main surfaces that face each other in a height direction orthogonal to the length direction; and first and second side surfaces that face each other in a width direction orthogonal to the length direction and the height direction. A coil shaft of the coil is parallel to the first main surface, and in the circulation part 34 of at least the one coil conductor 32, a first gap 51 is provided only between a first surface thereof and the insulation layer 31. Thus, by forming the first gap 51, a floating capacitance between the adjacent coil conductors 32 can be reduced. Therefore, a high-frequency characteristic is further improved.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a multilayer coil component.

Background Art

[0002] Patent Document 1 discloses a multilayer electronic component in which a coil conductor and an insulating layer made of a magnetic or non-magnetic material are laminated to form a coil inside, terminal electrodes are provided at both ends in the lamination direction, and at least one terminal electrode on one end side is connected to the coil end inside the laminate through a conductor-filled through hole provided in one or more insulating layers and a lead-out electrode provided to cover the end of the through hole. The area of the lead-out electrode is set to be 3 times or more the cross-sectional area of the through hole and 1 / 3 or less of the inner area of the coil when the laminate is viewed through in the lamination direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A multilayer coil component (hereinafter also referred to as a horizontally wound multilayer inductor) in which a coil is provided so that the coil axis is parallel to the mounting surface, like the multilayer electronic component described in Patent Document 1, has a structure suitable for high-frequency applications. However, in a conventional horizontally wound multilayer inductor, the insulating layer between coil conductors is formed of ferrite having a dielectric constant of about 15, so the high-frequency characteristics are affected by stray capacitance. In particular, in recent years, further high-frequency characteristics have been demanded, and the stray capacitance between adjacent coil conductors has hindered the improvement of high-frequency characteristics.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a multilayer coil component having excellent high-frequency characteristics.

Means for Solving the Problem

[0006] The laminated coil component of the present invention includes a laminate in which a plurality of insulating layers are laminated and which has a coil inside, a first external electrode and a second external electrode that are electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductors laminated together with the insulating layers through via conductors penetrating the insulating layers. Each coil conductor includes a circumferential portion and a land connected to the via conductor. The laminate has a first end face and a second end face facing each other in the length direction, a first main face and a second main face facing each other in the height direction orthogonal to the length direction, and a first side face and a second side face facing each other in the width direction orthogonal to the length direction and the height direction. The coil axis of the coil is parallel to the first main face. Each coil conductor has a first face facing a first direction parallel to the coil axis and a second face facing the opposite side of the first direction. A first gap is provided only between the circumferential portion of at least one of the coil conductors and the insulating layer.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a laminated coil component having excellent high-frequency characteristics.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the multilayer coil component of the present invention will be described. Note that the present invention is not limited to the following configuration, and may be appropriately changed without departing from the gist of the present invention. In addition, a combination of a plurality of the following individually preferred configurations is also the present invention.

[0010] The drawings shown below are schematic diagrams, and their dimensions, scales of aspect ratios, etc. may be different from those of actual products. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. Also, in each figure, the same elements will be denoted by the same reference numerals and redundant descriptions will be omitted.

[0011] In this specification, terms indicating the relationship between elements (for example, "parallel", "orthogonal", etc.) and terms indicating the shape of elements do not mean only a strictly literal aspect, but also a substantially equivalent range, for example, a range including a difference of about several%.

[0012] Each of the embodiments described below is an example, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only differences will be explained. In particular, for similar operational effects due to similar configurations, they will not be sequentially mentioned for each embodiment.

[0013] FIG. 1 is a perspective view schematically showing an example of a laminated coil component of the present invention. The laminated coil component 1 shown in FIG. 1 includes a laminate (element body) 10, a first external electrode 21 and a second external electrode 22 provided on the outer surface of the laminate 10. The laminate 10 has a rectangular parallelepiped shape having six faces. Although the configuration of the laminate 10 will be described later, a plurality of insulating layers and a plurality of coil conductors are laminated in the lamination direction, and a coil is provided inside. The first external electrode 21 and the second external electrode 22 are each electrically connected to the coil.

[0014] In the laminated coil component and the laminate in this specification, the length direction, the height direction, and the width direction are the L direction, the T direction, and the W direction in FIG. 1. Here, the length direction L, the height direction T, and the width direction W are orthogonal to each other. Here, the length direction L is a direction parallel to the lamination direction.

[0015] As shown in FIG. 1, the laminate 10 has a first end face 11 and a second end face 12 facing each other in the length direction L, a first main face 13 and a second main face 14 facing each other in the height direction T orthogonal to the length direction L, and a first side face 15 and a second side face 16 facing each other in the width direction W orthogonal to the length direction L and the height direction T.

[0016] Although not shown in FIG. 1, it is preferable that the laminate 10 has rounded corners and ridge lines. A corner is a portion where three faces of the laminate intersect, and a ridge line is a portion where two faces of the laminate intersect.

[0017] The first external electrode 21 covers, for example, as shown in FIG. 1, the entire first end face 11 of the laminate 10 and extends from the first end face 11 to cover a part of the first main face 13, a part of the second main face 14, a part of the first side face 15, and a part of the second side face 16.

[0018] The second external electrode 22 covers, for example, as shown in FIG. 1, the entire second end face 12 of the laminate 10 and extends from the second end face 12 to cover a part of the first main face 13, a part of the second main face 14, a part of the first side face 15, and a part of the second side face 16.

[0019] When mounting the laminated coil component 1 in which the first external electrode 21 and the second external electrode 22 are arranged as described above on a substrate, any one of the first main face 13, the second main face 14, the first side face 15, and the second side face 16 of the laminate 10 serves as the mounting face.

[0020] However, the first external electrode 21 only needs to extend from at least a part of the first end face 11 of the laminate 10 to the mounting face of the laminate 10.

[0021] Similarly, the second external electrode 22 only needs to extend from at least a part of the second end face 12 of the laminate 10 to the mounting face of the laminate 10.

[0022] The first external electrode 21 and the second external electrode 22 may each have a single-layer structure or a multi-layer structure.

[0023] When the first external electrode 21 and the second external electrode 22 each have a single-layer structure, examples of the constituent material of each external electrode include Ag, Au, Cu, Pd, Ni, Al, alloys containing at least one of these metals, and the like.

[0024] When the first external electrode 21 and the second external electrode 22 each have a multi-layer structure, each external electrode may have, for example, a base electrode layer containing Ag, a Ni film, and a Sn film in this order from the surface side of the laminate 10.

[0025] The size of the laminated coil component of the present invention is not particularly limited, but it is preferably 1608 size, 0603 size, 0402 size or 1005 size.

[0026] FIG. 2 is an exploded perspective view schematically showing an example of a laminate constituting the laminated coil component shown in FIG. 1.

[0027] As shown in FIG. 2, the laminate 10 is configured by laminating a plurality of insulating layers 31a, 31b, 31c, 31d, 31e and 31f from the first end face 11 side to the second end face 12 side of the laminate 10 in the lamination direction (here, the length direction L). Hereinafter, the insulating layers 31a, 31b, 31c, 31d, 31e and 31f will also be collectively referred to as the insulating layer 31.

[0028] In this specification, the direction in which a plurality of insulating layers constituting the laminate are stacked is referred to as the lamination direction.

[0029] In FIG. 2, the insulating layer 31e is disposed on the lower side in the lamination direction (the first end face 11 side of the laminate 10), and the insulating layer 31f is disposed on the upper side in the lamination direction (the second end face 12 side of the laminate 10).

[0030] Examples of the constituent material of each insulating layer 31 include magnetic materials such as ferrite materials.

[0031] The insulating layers 31a, 31b, 31c and 31d are each provided with a coil conductor 32a, 32b, 32c and 32d and via conductors 33a, 33b, 33c and 33d. The insulating layer 31e is provided with a via conductor 33e and a land 35e. The insulating layer 31f is provided with a via conductor 33f and a land 35f. The insulating layer 31e may be one layer or two or more layers. Similarly, the insulating layer 31f may be one layer or two or more layers. Hereinafter, the coil conductors 32a, 32b, 32c and 32d will also be collectively referred to as the coil conductor 32.

[0032] The coil conductors 32a, 32b, 32c, and 32d are respectively provided on the main surfaces of the insulating layers 31a, 31b, 31c, and 31d, and are laminated together with the insulating layers 31a, 31b, 31c, 31d, 31e, and 31f. In FIG. 2, each coil conductor 32 has a 3 / 4 turn shape, and four insulating layers 31 arranged in the order of the insulating layers 31a, 31b, 31c, and 31d are repeatedly laminated as one unit (for 3 turns).

[0033] Further, the coil conductors 32a, 32b, 32c, and 32d each include an annular circumferential portion 34a, 34b, 34c, and 34d with one part missing and partially having a gap, and lands 35a, 35b, 35c, and 35d. Lands 35a, 35b, 35c, 35d are provided at both ends of each circumferential portion 34a, 34b, 34c, 34d. Hereinafter, the circumferential portions 34a, 34b, 34c, and 34d are also collectively referred to as the circumferential portion 34.

[0034] The via conductors 33a, 33b, 33c, 33d, 33e, and 33f are respectively provided so as to penetrate the insulating layers 31a, 31b, 31c, 31d, 31e, and 31f in the lamination direction. Hereinafter, the via conductors 33a, 33b, 33c, 33d, 33e, and 33f are also collectively referred to as the via conductor 33.

[0035] Lands 35e and 35f are respectively provided immediately above the via conductors 33e and 33f. The lands 35a, 35b, 35c, 35d, 35e, and 35f are preferably slightly larger than the line widths of the circumferential portions 34a, 34b, 34c, and 34d. Hereinafter, the lands 35a, 35b, 35c, 35d, 35e, and 35f are also collectively referred to as the land 35. The land 35 is larger than the adjacent via conductor 33, and when viewed from the lamination direction (length direction L), the via conductor 33 adjacent to the land 35 is within the region of the land 35.

[0036] Examples of the constituent materials of each coil conductor 32 including the circumferential portion 34 and the land 35 and each via conductor 33 include Ag, Au, Cu, Pd, Ni, Al, alloys containing at least one of these metals, and the like.

[0037] The plurality of insulating layers 31a, 31b, 31c, 31d, 31e, and 31f configured as described above are laminated in the stacking direction. As a result, the laminate 10 is formed, and the plurality of coil conductors 32a, 32b, 32c, and 32d are electrically connected via the via conductors 33a, 33b, 33c, and 33d. As a result, a solenoid-shaped coil having a coil axis parallel to the stacking direction is formed within the laminate 10.

[0038] Also, the via conductor 33e and the land 35e serve as a first lead conductor within the laminate 10 and are exposed on the first end face 11 of the laminate 10. That is, the first lead conductor includes the via conductor 33e and the land 35e. As will be described later, the first lead conductor connects between the first external electrode 21 and the coil conductor 32a facing it within the laminate 10.

[0039] The via conductor 33f and the land 35f serve as a second lead conductor within the laminate 10 and are exposed on the second end face 12 of the laminate 10. That is, the second lead conductor includes the via conductor 33f and the land 35f. As will be described later, the second lead conductor connects between the second external electrode 22 and the coil conductor 32d facing it within the laminate 10.

[0040] When viewed from the stacking direction (length direction L), it is preferable that the coil conductors 32 overlap each other. Also, when viewed from the stacking direction, the coil may have a shape composed of straight portions (e.g., a polygonal shape such as a rectangle) as shown in FIG. 2, a shape composed of curved portions (e.g., a circular shape), or a shape composed of straight portions and curved portions.

[0041] FIG. 3 is a side view schematically showing a perspective view of an example of the internal structure of the laminate constituting the laminated coil component shown in FIG. 1.

[0042] As shown in FIG. 3, in the multilayer coil component 1, since a plurality of insulating layers 31 are laminated in the length direction L, the length direction L is the lamination direction. Further, the lamination direction of the laminate 10 and the coil axis A of the coil 30 are parallel to any one of the first main surface 13, the second main surface 14, the first side surface 15, or the second side surface 16, which is the mounting surface, for example, the first main surface 13. That is, the multilayer coil component 1 is a horizontally wound multilayer inductor in which the coil 30 is provided such that the coil axis A is parallel to the mounting surface.

[0043] As shown in FIG. 3, actually, no boundary is visible between adjacent insulating layers 31.

[0044] The first lead conductor 41 extends in the lamination direction within the laminate 10 and linearly connects between the first external electrode 21 provided on the first end surface 11 and the coil conductor 32a facing the first external electrode 21. Similarly, the second lead conductor 42 extends in the lamination direction within the laminate 10 and linearly connects between the second external electrode 22 provided on the second end surface 12 and the coil conductor 32d facing the second external electrode 22.

[0045] When viewed from the lamination direction (length direction L), it is preferable that the via conductors constituting the lead conductors overlap each other, but the via conductors constituting the lead conductors do not have to be strictly linearly aligned.

[0046] Also, in FIGS. 2 and 3, the case where the number of laminations of the coil conductors 32 for forming three turns of the coil 30 is 4, that is, the repeating shape is a 3 / 4 turn shape is illustrated, but the number of laminations of the coil conductors 32 for forming one turn of the coil 30 is not particularly limited. For example, the number of laminations of the coil conductors 32 for forming one turn of the coil 30 may be 2, that is, the repeating shape may be a 1 / 2 turn shape.

[0047] Also, the number of laminations of the coil conductors 32, that is, the total number of coil conductors 32 included in the laminate 10 is not particularly limited, but may be 8 or more and 32 or less.

[0048] FIG. 4 is a cross-sectional view schematically showing an example of a cross-section along line segment A1-A1 of the laminated coil component shown in FIG. 1. Note that FIG. 4 shows a cross-section of the circumferential portion 34 of the coil conductor 32.

[0049] As shown in FIG. 4, when looking at a cross-section in a direction perpendicular to the direction in which the coil conductor 32 extends, the cross-sectional shape of the coil conductor 32 is a flat shape (longitudinal shape), and its longitudinal direction is orthogonal to the lamination direction (length direction L). In the example shown in FIG. 4, the cross-sectional shape of the coil conductor 32 is an ellipse whose major axis is orthogonal to the lamination direction, but the cross-sectional shape of the coil conductor 32 is not particularly limited. For example, it may be a rectangular shape in which the lengths of a pair of opposite sides in the lamination direction are the same, or a trapezoidal shape in which the lengths of a pair of opposite sides in the lamination direction are different.

[0050] Also, as shown in FIG. 4, each of the coil conductors 32 has a first surface 36 facing a first direction parallel to the coil axis A and a second surface 37 facing the side opposite to the first direction. Both the first surface 36 and the second surface 37 extend in a direction orthogonal to the lamination direction.

[0051] And, in the circumferential portion 34 of each coil conductor 32, a first gap 51 is provided only between its first surface 36 and the insulating layer 31. By forming the first gap 51 in this way, the stray capacitance between adjacent coil conductors 32 can be reduced. Generally, a horizontally wound laminated inductor has a lower stray capacitance compared to a laminated coil component in which the coil is provided such that the coil axis is perpendicular to the mounting surface. However, by providing air having a lower dielectric constant than the insulating layer 31 (for example, a ferrite material) in the laminate 10 as in the present embodiment, the stray capacitance can be further reduced. Therefore, the high-frequency characteristics are further improved. Therefore, according to the present embodiment, the high-frequency characteristics of the laminated coil component 1 which is a horizontally wound laminated inductor can be further improved. Note that it is preferable from the viewpoint of improving the high-frequency characteristics that a gap is provided on one side of the circumferential portion 34 of all the coil conductors 32, but it is sufficient that a gap is provided on one side of the circumferential portion 34 of at least one coil conductor 32. Also, the gap may be interrupted in the middle, but it is preferable from the viewpoint of improving the high-frequency characteristics that it is provided over the entire one side (the entire area of one side) of the coil conductor 32.

[0052] Also, if gaps are provided on both sides of the first surface 36 and the second surface 37 of each coil conductor 32, the flexural strength when the laminated coil component 1 is mounted will decrease, and it will become vulnerable to impact. Further, when manufacturing such a laminated coil component by the manufacturing method described later, it becomes necessary to print a resin paste after printing the conductor pattern for the coil conductor, and there is a possibility that it may not be easy to manufacture. On the other hand, in the laminated coil component 1, in the circumferential portion 34 of each coil conductor 32, a first gap 51 is provided only between its first surface 36 and the insulating layer 31, and no gap is provided between the second surface 37 and the insulating layer 31 or between the side surfaces of the circumferential portion 34 (the inner peripheral side surface and the outer peripheral side surface of the circumferential portion 34) and the insulating layer 31. Therefore, a decrease in the flexural strength when the laminated coil component 1 is mounted can be suppressed. Also, the laminated coil component 1 can be easily manufactured by the manufacturing method described later.

[0053] Note that the gap only needs to be provided only on one side of the circumferential portion 34 of the coil conductor 32, that is, only between the first surface 36 or the second surface 37 and the insulating layer 31. Among the coil conductors 32 with a gap provided in the circumferential portion 34, for some coil conductors 32, the first gap 51 may be provided only between the first surface 36 of the circumferential portion 34 and the insulating layer 31, and for the remaining coil conductors 32, the first gap 51 may be provided only between the second surface 37 of the circumferential portion 34 and the insulating layer 31.

[0054] Also, in this specification, the inner peripheral side and the outer peripheral side of the coil conductor (circumferential portion) respectively mean the coil axis side of the coil and the opposite side (outside of the coil).

[0055] Here, the results of simulating the electrical characteristics of the multilayer coil component 1 according to this embodiment will be described. Here, as Example 1 of the multilayer coil component 1 according to this embodiment, a model corresponding to a 1608-size multilayer coil component was used. The dimensions of the laminate of the model in the length direction L, width direction W, and height direction T were 1.555 mm, 0.759 mm, and 0.759 mm, respectively. Also, the thickness of each first gap was 5 μm, and the thickness of each coil conductor was 33 μm. Also, as Comparative Example 1 for the multilayer coil component 1 according to this embodiment, a model that was the same except that the first gap was not provided was used.

[0056] As a result, while the stray capacitance of Example 1 was 0.32 pF, the stray capacitance of Comparative Example 1 was 0.48 pF, indicating that the stray capacitance can be further reduced according to this embodiment.

[0057] FIG. 5 is a graph showing the frequency characteristics of the impedance of Example 1 and Comparative Example 1.

[0058] As shown in FIG. 5, the peak value of the impedance in Example 1 was 210 Ω at a frequency of 1000 MHz (= 1 GHz), whereas the peak value of the impedance in Comparative Example 1 was 180 Ω at a frequency of 700 MHz. That is, Example 1 was compatible with a higher frequency than Comparative Example 1. Also, in Example 1, a high impedance was maintained even after a frequency of 1000 MHz. Therefore, according to the present embodiment, it is possible to correspond to a higher frequency.

[0059] FIG. 6 is a cross-sectional view schematically showing an enlarged view of the vicinity of the coil conductor in FIG. 4.

[0060] As shown in FIG. 6, it is preferable that the width w1 of the first gap 51 is smaller than the width (line width) W1 of the circumferential portion 34. In this way, by providing the first gap 51 only inside the coil conductor 32, it is difficult for the insulating layer 31 (for example, ferrite) to crack, and a highly reliable structure is obtained. Specifically, the width w1 of the first gap 51 may be in the range of 60% to 90% with respect to the width W1 of the circumferential portion 34. Here, the width w1 of the first gap 51 and the width W1 of the circumferential portion 34 compared with each other are the dimensions in the height direction T of the first gap 51 and the circumferential portion 34 when viewed from the LT cross-section passing through the coil axis. The LT cross-section passing through the coil axis is a plane parallel to the length direction L and the height direction T of the laminate 10 and cut so as to pass through the coil axis. The cross-section cut so as to pass through the coil axis means a cross-section in which the coil axis and the cut surface exist on the same plane.

[0061] Also, as shown in FIG. 6, the thickness T1 of the circumferential portion 34 may be 5 μm or more and 45 μm or less, and the thickness t1 of the first gap 51 may be 1 μm or more and 15 μm or less, or may be 2 μm or more and 5 μm or less. If the first gap 51 is made too large, the thickness of the circumferential portion 34 will be restricted, and as a result, there is a possibility that a low-resistance laminated coil component cannot be realized. Therefore, by keeping the thickness t1 of the first gap 51 thin within the above range, a laminated coil component with excellent high-frequency characteristics and low resistance can be realized. Specifically, by setting the thickness t1 of the first gap 51 to 1 μm or more, the high-frequency characteristics of the laminated coil component 1 can be more reliably improved, and by setting it to 2 μm or more, it can be further improved. Also, by setting the thickness t1 of the first gap 51 to 15 μm or less, the resistance of the laminated coil component 1 can be reduced, and by setting it to 5 μm or less, it can be further reduced.

[0062] Note that the thicknesses t1 and T1 compared with each other here are both measured at the central portion in the line width direction of the circumferential portion 34 when viewing the LT cross section passing through the coil axis.

[0063] FIG. 7 is a diagram schematically showing a perspective view of an example of the internal structure of the laminate constituting the laminated coil component shown in FIG. 1, and is a view seen from the second end face side of the laminate. FIG. 8 is a cross-sectional view schematically showing an example of a cross section along the line segment A1 - A1 of the laminated coil component shown in FIG. 7.

[0064] As shown in FIG. 7, it is preferable that the width W2 of the land 35 is larger than the width W1 of the circumferential portion 34. Note that the width W2 of the land 35 is the dimension in the line width direction of the circumferential portion 34. Further, as shown in FIG. 8, in the land 35 of the coil conductor 32 provided with the first gap 51, a second gap 52 is provided between the surface on the side to which the via conductor 33 is not connected and the insulating layer 31, and the second gap 52 is preferably thicker than the first gap 51 (that is, the thickness t2 of the second gap 52 > the thickness t1 of the first gap 51). Here, the thickness t1 of the first gap 51 to be compared with the thickness t2 of the second gap 52 is to be measured at the central portion in the line width direction of the circumferential portion 34 when viewing the LT cross section passing through the coil axis. Also, the thickness t2 of the second gap 52 to be compared with the thickness t1 of the first gap 51 is to be measured at the central portion in the line width direction of the land 35 when viewing the LT cross section passing through the center of the land 35. By providing a thicker gap in this way, the parasitic capacitance can be further reduced, so that the high-frequency characteristics of the multilayer coil component 1 can be further improved. Further, since the width W2 of the land 35 is larger than the line W1 of the circumferential portion 34, the surface area of the land 35 can be increased. As a result, the second gap 52 thicker than the first gap 51 can be easily manufactured.

[0065] As shown in FIGS. 2 and 7, the first gap 51 may be provided between the first surface of the entire circumferential portion 34 and the insulating layer 31.

[0066] Here, with reference to FIG. 7, the generation of cracks starting from the first gap inside the element of the multilayer coil component 1 mounted on the substrate will be described.

[0067] As shown in FIG. 7, the interval in the height direction between the coil 30 and the first main surface 13 is defined as the side gap G1, and the interval in the height direction between the coil 30 and the second main surface 14 is defined as the side gap G2. Here, the first main surface 13 is the mounting surface.

[0068] When the substrate on which the multilayer coil component is mounted is bent, stress is particularly applied in the region near the end of the external electrode extending on the mounting surface inside the body of the multilayer coil component. When the side gap G1 becomes small, the distance between the first main surface 13 which is the mounting surface and the coil conductor 32 becomes close, and the distance to the first gap 51 provided on the coil conductor 32 also becomes close. And when the side gap G1 becomes too small, the first gap 51 approaches the region where the above-mentioned stress is particularly applied, and cracks may occur inside the body starting from the first gap 51.

[0069] Therefore, from the viewpoint of suppressing the generation of cracks due to the bending of the substrate, it is preferable that the side gap G1 is ensured to a certain extent. Specifically, it is preferably 43 μm or more, more preferably 44 μm or more, and still more preferably 46 μm or more. By setting the lower limit of the side gap G1 in this way, it is possible to prevent cracks from occurring due to the bending of the substrate. The upper limit of the side gap G1 is not particularly limited, but it may be 150 μm or less. Also, the side gap G2 is not particularly limited, but like the side gap G1, it may be 43 μm or more and 150 μm or less.

[0070] When the size of the multilayer coil component becomes small, the lower limit of the required side gap G1 also becomes small. Therefore, in the multilayer coil component 1 that satisfies the above side gap G1, the generation of cracks due to the bending of the substrate can be more effectively prevented. From such a viewpoint, the size of the multilayer coil component 1 is preferably 1608 size or less, and more preferably, for example, 1608 size, 1005 size, 0603 size or 0402 size.

[0071] In a horizontally wound multilayer inductor, generally, there is a lot of conductive paste such as Ag paste at the location where the land is formed, and during manufacturing, a higher pressure is applied than the circumferential portion of the same layer, and the distance to the adjacent coil conductor tends to be closer than the circumferential portion of the same layer.

[0072] Therefore, also in this embodiment, as shown in FIG. 8, in adjacent coil conductors 32, the distance D1 between the opposing lands 35 and the circumferential portion 34 may be smaller than the distance D2 between the two opposing circumferential portions 34. Here, the distance D1 between the opposing land 35 and the circumferential portion 34 to be compared with the distance D2 is to be measured at the central portion in the line width direction of the land 35 when looking at the LT cross-section passing through the center of the land 35. Further, the distance D2 between the two opposing circumferential portions 34 to be compared with the distance D1 is to be measured at the central portion in the line width direction of the circumferential portion 34 when looking at the LT cross-section passing through the coil axis. And in this case, it is preferable that a second gap 52 is provided between the surfaces of the two opposing lands 35 on the side where the via conductor 33 is not connected and the insulating layer 31. In this way, by providing the second gap 52 on both surfaces of the two lands 35 close to the adjacent coil conductor 32 on the side where the via conductor 33 is not connected, the parasitic capacitance can be more effectively reduced.

[0073] FIG. 9 is an exploded perspective view schematically showing another example of the laminate constituting the laminated coil component shown in FIG. 1.

[0074] As shown in FIG. 9, the first gap 51 may be provided between the first surface of only a part of the circumferential portion 34 and the insulating layer 31. Thereby, it is possible to achieve both the effect of reducing the parasitic capacitance by the first gap 51 and enhancing the high-frequency characteristics, and the effect of increasing the inductance by bringing the coil conductor 32 as close as possible to the insulating layer 31 (here, preferably a magnetic material) in the region where the first gap 51 does not exist. Further, by partially providing the first gap 51, the body strength can be increased as compared with the case where it is provided on the entire one surface of the circumferential portion 34 (see FIGS. 2 and 7).

[0075] As shown in FIG. 9, the first gap 51 may extend from near one land 35 to the middle portion of the circumferential portion 34.

[0076] Hereinafter, an example of the manufacturing method of the laminated coil component of the present invention will be described.

[0077] <Manufacturing Process of Magnetic Material> First, weigh Fe2O3, ZnO, CuO, and NiO so that they are in a predetermined ratio.

[0078] Next, put these weighed substances, pure water, etc. into a ball mill together with PSZ (partially stabilized zirconia) media, mix them, and then grind them. The mixing and grinding time is, for example, 4 hours or more and 8 hours or less.

[0079] Then, after drying the obtained ground material, pre-calcine it. The pre-calcination temperature is, for example, 700°C or more and 800°C or less. The pre-calcination time is, for example, 2 hours or more and 5 hours or less.

[0080] In this way, a powdery magnetic material, more specifically, a powdery magnetic ferrite material is produced.

[0081] The ferrite material is preferably a Ni-Cu-Zn-based ferrite material.

[0082] When the total amount of the Ni-Cu-Zn-based ferrite material is 100 mol%, it preferably contains Fe in terms of Fe2O3 conversion of 40 mol% or more and 49.5 mol% or less, Zn in terms of ZnO conversion of 2 mol% or more and 35 mol% or less, Cu in terms of CuO conversion of 6 mol% or more and 13 mol% or less, and Ni in terms of NiO conversion of 10 mol% or more and 45 mol% or less.

[0083] The Ni-Cu-Zn-based ferrite material may further contain additives such as Co, Bi, Sn, and Mn.

[0084] The Ni-Cu-Zn-based ferrite material may further contain unavoidable impurities.

[0085] <Manufacturing Process of Green Sheet> First, a magnetic material, an organic binder such as polyvinyl butyral resin, an organic solvent such as ethanol and toluene, and a plasticizer, etc. are put into a ball mill together with PSZ media and mixed, and then pulverized to produce a slurry.

[0086] Next, the slurry is formed into a sheet of a predetermined thickness by the doctor blade method or the like, and then punched into a predetermined shape to produce a green sheet. Regarding the thickness of the green sheet, for example, it is set to 20 μm or more and 30 μm or less. Regarding the shape of the green sheet, for example, it is rectangular.

[0087] As the material of the green sheet, instead of the magnetic material, a non-magnetic material such as a borosilicate glass material may be used, or a mixed material of a magnetic material and a non-magnetic material may be used.

[0088] <Conductor Pattern Formation Step> First, via holes are formed by performing laser irradiation on a predetermined portion of the green sheet.

[0089] Next, after applying the resin paste onto the surface of the green sheet by means of screen printing or the like, a conductive paste such as Ag paste is applied onto the surface of the green sheet while filling the via holes by means of screen printing or the like. The resin paste is obtained by containing a resin (such as an acrylic resin) that burns out during firing in a solvent (such as isophorone), and is applied to the location where the formation of voids is planned. Thereby, while forming a conductor pattern for via conductor in the via holes with respect to the green sheet, a conductor pattern for coil conductor connected to the conductor pattern for via conductor is formed on the surface of the green sheet via a resin pattern for void formation. Thereafter, a resin paste may be applied onto the conductor pattern for coil conductor to further form a resin pattern for void formation. In this way, a coil sheet on which a conductor pattern for coil conductor, a conductor pattern for via conductor, and a resin pattern for void formation are formed on the green sheet is produced. On the coil sheet, a conductor pattern for coil conductor corresponding to the coil conductor 32 shown in FIG. 2 and a conductor pattern for via conductor corresponding to the via conductor 33 (excluding the via conductors 33e and 33f) shown in FIG. 2 are formed. The resin pattern for void formation is made substantially the same as the conductor pattern for coil conductor, and it is preferable that the line width of the resin pattern for void formation is slightly smaller than the line width of the conductor pattern for coil conductor.

[0090] Note that the resin paste does not necessarily need to be applied to the location where the formation of the second void 52 to be formed in the land portion is planned. Even in that case, there is a lot of conductive paste at that location, and the second void 52 can be formed due to the shrinkage of the conductive paste.

[0091] Also, separately from the coil sheet, a via sheet on which a conductor pattern for via conductor corresponding to the via conductors 33e and 33f shown in FIG. 2 and a conductor pattern for land corresponding to the lands 35e and 35f shown in FIG. 2 are formed is produced.

[0092] <Manufacturing process of the laminate block> After laminating the coil sheet and the via sheet in the stacking direction (length direction L) in the order corresponding to FIG. 2, a laminate block is produced by thermocompression bonding.

[0093] <Manufacturing Process of Laminated Body and Coil> First, a laminated body block is cut into a predetermined size using a dicing saw or the like to produce fragmented chips.

[0094] Next, the fragmented chips are fired. The firing temperature is, for example, 900°C or higher and 920°C or lower. The firing time is, for example, 2 hours or longer and 4 hours or shorter.

[0095] When the fragmented chips are fired, the green sheets of the coil sheet and via sheet become insulating layers.

[0096] Also, when the fragmented chips are fired, the conductor patterns for coil conductors, via conductors, and lands become coil conductors, via conductors, and lands, respectively. As a result, a coil in which a plurality of coil conductors laminated in the stacking direction are electrically connected via via conductors is produced. Also, the resin pattern for void formation burns out and the conductor pattern shrinks more than the green sheet, forming voids.

[0097] As described above, a laminated body in which a plurality of insulating layers are laminated in the stacking direction and a coil is incorporated inside is produced.

[0098] For the laminated body, for example, barrel polishing may be performed to round the corners and ridges.

[0099] <Formation Process of External Electrodes> First, a conductive paste layer is formed by applying a conductive paste such as a paste containing Ag and glass frit to the first end face and the second end face from which the coil is drawn out among the outer surfaces of the laminated body.

[0100] Next, the conductive paste layer is baked to form a base electrode of the external electrode. The baking temperature is, for example, 800°C or higher and 820°C or lower. The thickness of the base electrode is, for example, 5 μm.

[0101] Then, on the surface of the base electrode, an Ni-plated electrode and an Sn-plated electrode are sequentially formed by electrolytic plating or the like. Thereby, an external electrode having a base electrode, an Ni-plated electrode, and an Sn-plated electrode in this order is formed.

[0102] As described above, the laminated coil component is manufactured.

[0103] Hereinafter, regarding the laminated coil component according to the present embodiment, the results of verifying the side gap amount that does not cause cracks inside the element body will be described.

[0104] As samples, 15 laminated coil components were produced by the above-described manufacturing method, in which the amounts of side gaps G1 and G2 were different only between the first surface and the insulating layer in the circumferential portions of all the coil conductors. All the laminated coil components had a size of 1608. When the dimensions of the 15 samples were measured and the average values were obtained, the dimensions of the laminated coil component including the external electrode in the length direction L, width direction W, and height direction T were 1.530 mm, 0.822 mm, and 0.822 mm, respectively, and the dimensions of the laminate excluding the external electrode in the length direction L, width direction W, and height direction T were 1.372 mm, 0.783 mm, and 0.783 mm, respectively.

[0105] FIG. 10 is a schematic diagram showing a test method in the verification of the side gap amount.

[0106] As shown in FIG. 10, first, the laminated coil component 81 as a sample was mounted on the substrate 82 with the first main surface as the mounting surface, and the substrate 82 was supported at the support portions 83a and 83b located 45 mm in the length direction from the center of the laminated coil component 81 so that the laminated coil component 81 was on the lower side. Then, stress was applied to the central portion of the laminated coil component 81 from the back surface of the substrate 82 on which the laminated coil component 81 was not mounted until the deflection amount of the substrate 82 reached 3 mm, and it was confirmed whether or not cracks occurred inside the element body of the laminated coil component 81. Note that a deflection amount of 2 mm is sufficient for practical use, but here the test was performed with a margin of 3 mm. The results are shown in Table 1 below.

[0107]

Table 1

[0108] From this result, it can be seen that the side gap G1 is preferably 43 μm or more, more preferably 44 μm or more, and even more preferably 46 μm or more.

[0109] The following content is disclosed in this specification.

[0110] <1> A laminate in which a plurality of insulating layers are laminated and which has a coil inside, a first external electrode and a second external electrode electrically connected to the coil, The coil is formed by electrically connecting a plurality of coil conductors laminated together with the insulating layer through via conductors penetrating the insulating layer, The coil conductor includes a circumferential portion and a land connected to the via conductor, The laminate has a first end face and a second end face opposite to each other in the length direction, a first main face and a second main face opposite to each other in the height direction orthogonal to the length direction, and a first side face and a second side face opposite to each other in the width direction orthogonal to the length direction and the height direction, The coil axis of the coil is parallel to the first main face, Each of the coil conductors has a first surface facing a first direction parallel to the coil axis and a second surface facing the opposite side of the first direction, A laminated coil component in which a first gap is provided only between the circumferential portion of at least one of the coil conductors and the insulating layer.

[0111] <2> The laminated coil component according to <1>, wherein a first gap is provided only between the circumferential portion of all the coil conductors and the insulating layer.

[0112] <3> The first gap is provided only between the circumferential portion of at least one of the coil conductors and the insulating layer on either the first surface or the second surface thereof. For some of the coil conductors, the first gap is provided only between the first surface of the circumferential portion and the insulating layer. For the remaining coil conductors, the first gap is provided only between the second surface of the circumferential portion and the insulating layer. The multilayer coil component according to <1>.

[0113] <4> The first gap is provided only between the circumferential portion of all of the coil conductors and the insulating layer on either the first surface or the second surface thereof. For some of the coil conductors, the first gap is provided only between the first surface of the circumferential portion and the insulating layer. For all of the remaining coil conductors, the first gap is provided only between the second surface of the circumferential portion and the insulating layer. The multilayer coil component according to <3>.

[0114] <5> The width of the first gap is smaller than the width of the circumferential portion. The multilayer coil component according to any one of <1> to <4>.

[0115] <6> The width of the land is larger than the width of the circumferential portion. A second gap is provided between the surface of the land of the coil conductor provided with the first gap and the insulating layer on the side where the via conductor is not connected. The second gap is thicker than the first gap. The multilayer coil component according to any one of <1> to <5>.

[0116] <7> The first gap is provided only between the insulating layer and a part of the first surface of the circumferential portion. The multilayer coil component according to any one of <1> to <6>.

[0117] <8> In the adjacent coil conductors, the distance between the opposing lands and the circumferential portions is smaller than the distance between two opposing circumferential portions. In the laminated coil component according to any one of <1> to <7>, in the two opposing lands via the via conductor, a second gap is provided between the surface on the side where the via conductor is not connected and the insulating layer.

[0118] <9> In the laminated coil component according to any one of <1> to <8>, the thickness of the first gap is 1 μm or more and 15 μm or less.

[0119] <10> The first main surface is a mounting surface. In the laminated coil component according to any one of <1> to <9>, the distance in the height direction between the coil and the first main surface is 43 μm or more.

Explanation of reference numerals

[0120] 1, 81 Laminated coil component 10 Laminate 11 First end face 12 Second end face 13 First main surface 14 Second main surface 15 First side face 16 Second side face 21 First external electrode 22 Second external electrode 30 Coil 31, 31a, 31b, 31c, 31d, 31e, 31f Insulating layer 32, 32a, 32b, 32c, 32d Coil conductor 33, 33a, 33b, 33c, 33d, 33e, 33f Via conductor 34, 34a, 34b, 34c, 34d Circumferential portion 35, 35a, 35b, 35c, 35d, 35e, 35f Land 36 First surface 37 Second surface 41 First lead-out conductor 42 Second lead conductor 51 First gap 52 Second gap 82 Substrate 83a, 83b Support portions A Coil axis of the coil G1 Distance in the height direction between the coil and the first main surface G2 Distance in the height direction between the coil and the second main surface

Claims

1. A laminate in which a plurality of insulating layers are laminated and which has a coil inside, a first external electrode and a second external electrode electrically connected to the coil, wherein the coil is formed by electrically connecting a plurality of coil conductors laminated together with the insulating layer via via conductors penetrating the insulating layer, each of the coil conductors includes a circumferential portion and a land connected to the via conductor, the laminate has a first end face and a second end face facing each other in the length direction, a first main face and a second main face facing each other in the height direction orthogonal to the length direction, and a first side face and a second side face facing each other in the width direction orthogonal to the length direction and the height direction, the coil axis of the coil is parallel to the first main face, each of the coil conductors has a first face facing a first direction parallel to the coil axis and a second face facing the side opposite to the first direction, a laminated coil component in which a first gap is provided only between the circumferential portion of at least one of the coil conductors and the insulating layer.

2. The laminated coil component according to claim 1, wherein the first gap is provided only between the circumferential portion of all of the coil conductors and the insulating layer.

3. A first gap is provided only between the circumferential portion of at least one of the coil conductors and the insulating layer, a first gap is provided only between the circumferential portion of some of the coil conductors and the insulating layer, a first gap is provided only between the circumferential portion of the remaining coil conductors and the insulating layer. The laminated coil component according to claim 1.

4. A first gap is provided only between the circumferential portion of all of the coil conductors and the insulating layer, a first gap is provided only between the circumferential portion of some of the coil conductors and the insulating layer, a first gap is provided only between the circumferential portion of all of the remaining coil conductors and the insulating layer. The laminated coil component according to claim 3.

5. The laminated coil component according to any one of claims 1 to 4, wherein the width of the first gap is smaller than the width of the circumferential portion.

6. The width of the land is larger than the width of the circumferential portion, The land of the coil conductor provided with the first gap has a second gap provided between the surface on the side where the via conductor is not connected and the insulating layer. The second gap is thicker than the first gap. The multilayer coil component according to any one of claims 1 to 4. **Claim 7** The first gap is provided between the first surface of only a part of the circumferential portion and the insulating layer. The multilayer coil component according to any one of claims 1 to 4. **Claim 8** In the adjacent coil conductors, the distance between the opposing lands and the circumferential portion is smaller than the distance between the two opposing circumferential portions. Both of the two opposing lands via the via conductor have a second gap provided between the surface on the side where the via conductor is not connected and the insulating layer. The multilayer coil component according to any one of claims 1 to 4. **Claim 9** The thickness of the first gap is 1 μm or more and 15 μm or less. The multilayer coil component according to any one of claims 1 to 4. **Claim 10** The first main surface is a mounting surface. The interval in the height direction between the coil and the first main surface is 43 μm or more. The multilayer coil component according to any one of claims 1 to 4.

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