Inductor component and electronic component

Abstract

The present invention provides an inductor component capable of increasing the Q value. The inductor component includes a base body and a coil disposed within the base body and wound in an axial direction. The inner diameter of the coil is larger at both ends of the coil in the axial direction than at the center of the coil in the axial direction.

Description

Technical Field

[0001] The present invention relates to an inductor component and an electronic component. Background Art

[0002] Conventionally, an inductor component is described in Japanese Patent Application Laid-Open No. 2015-015297 (Patent Document 1). This inductor component includes a base body and a coil provided in the base body and wound in the axial direction.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-015297

[0004] However, it is known that the Q value of conventional inductor components could be increased. Specifically, in these inductor components, the inner diameter of the coil is constant in the axial direction. Consequently, the magnetic flux density around the axial ends of the coil is lower than that around the axial center of the coil, resulting in a decrease in inductance. As a result, current is concentrated at the coil ends, increasing power loss and thus reducing the Q value. Summary of the Invention

[0005] Therefore, the present disclosure is to provide an inductor component and an electronic component capable of increasing the Q value.

[0006] In order to solve the above-mentioned technical problems, an inductor component according to one embodiment of the present disclosure includes:

[0007] green body; and

[0008] The coil is arranged in the above-mentioned blank and wound along the axial direction.

[0009] Regarding the inner diameter of the coil, the inner diameters of both end portions of the coil in the axial direction are larger than the inner diameter of the central portion of the coil in the axial direction.

[0010] Here, the "inner diameter of the coil" refers to the inner diameter of the coil as measured on a cross-section perpendicular to the coil axis. If the coil is wound in an elliptical or polygonal pattern, the "inner diameter of the coil" varies within each turn. In this case, for example, the inner diameters of the coil's two ends and the center can be compared using the maximum value of the "inner diameter of the coil" within each turn.

[0011] According to the above embodiment, the inner diameter of the coil is larger at the axial ends than at the axial center. This prevents a decrease in magnetic flux density around the coil's ends, thus reducing the inductance. As a result, current is less likely to concentrate at the coil's ends, minimizing power loss. This improves L value acquisition efficiency and increases Q.

[0012] Additionally, in one embodiment of the inductor component,

[0013] The inner diameter of the coil continuously increases from the central portion of the coil toward both end portions of the coil.

[0014] According to the above embodiment, by forming the inner peripheral surface of the coil into a shape along the flow of magnetic flux, the flow of magnetic flux is less likely to be obstructed, and a decrease in magnetic flux density around both end portions of the coil can be further suppressed.

[0015] Preferably, in one embodiment of the inductor component,

[0016] The inner diameter of the coil increases in a step-like manner from the central portion of the coil toward the both ends of the coil.

[0017] According to the above embodiment, since the inner diameter of the coil can be changed in a step-like manner in the axial direction, the coil can be easily manufactured and the L value can be easily adjusted.

[0018] Preferably, in one embodiment of the inductor component,

[0019] The first external electrode and the second external electrode are provided on the base body and are electrically connected to the coil.

[0020] The blank is in the shape of a rectangular parallelepiped having a length, a width, and a height, wherein the length is greater than the width and the length is greater than the height. The blank comprises a first end face and a second end face located at both ends of the length direction, a first side face and a second side face located at both ends of the width direction, and a bottom face and a top face located at both ends of the height direction.

[0021] The axis of the coil is parallel to the width direction.

[0022] The first external electrode is provided only on the first end surface, and the second external electrode is provided only on the second end surface.

[0023] According to the above embodiment, external electrodes are placed only on the end faces of the base body. This eliminates the need for external electrodes on the top and bottom surfaces of the base body, preventing the flow of magnetic flux from being obstructed by the external electrodes. Furthermore, the absence of external electrodes on the top and bottom surfaces allows the inner diameter of the coil to be increased accordingly.

[0024] Preferably, in one embodiment of the inductor component,

[0025] The first end surface and the second end surface each have a recessed portion.

[0026] The recessed portion opens at the bottom surface.

[0027] The first external electrode is provided in the recessed portion of the first end surface.

[0028] The second external electrode is provided in the recessed portion of the second end surface.

[0029] According to the above embodiment, when the inductor component is mounted on a mounting substrate, a solder fillet is formed, and the mounting substrate's pads and the inductor component's external electrodes are electrically connected. Since the external electrodes are located in the recesses, a solder fillet corresponding to the recesses can be formed inside the blank. This formation of the solder fillet within the recesses of the external electrodes increases the size of the inductor component relative to the mounting area.

[0030] Preferably, in one embodiment of the inductor component,

[0031] The depth of the recessed portion along the longitudinal direction increases toward the center of the recessed portion in the width direction.

[0032] According to the above embodiment, the depth of the recess along the longitudinal direction increases toward the center of the recess in the width direction. Therefore, when the inductor component is mounted on a mounting substrate, the contact area (fixed area) with the solder increases compared to an inductor component with a planar end face, and the proportion of the fixed area to the solder surface area increases. Consequently, a joint with high fixing strength can be formed using a small amount of solder.

[0033] Preferably, in one embodiment of the inductor component,

[0034] The depth of the recessed portion along the longitudinal direction increases in a step-like manner toward the center of the recessed portion in the width direction.

[0035] When the inductor component of the above embodiment is formed layer by layer and stacked for production, the coil and the recessed portion can be formed simultaneously, thereby improving workability, reducing the number of steps, and reducing costs.

[0036] Preferably, in one embodiment of the inductor component,

[0037] The coil includes a winding portion wound in a spiral shape that overlaps each other when viewed from the axial direction, a first lead portion separated from the winding portion and connected to the first external electrode, and a second lead portion separated from the winding portion and connected to the second external electrode.

[0038] When viewed from the height direction, the inner surface of the recessed portion follows the outer shape of the wound portion.

[0039] Here, the “outer shape of the wound portion” refers to the outer edge of the wound portion in a direction perpendicular to the axial direction.

[0040] According to the above embodiment, the recessed portion can be enlarged to the maximum extent possible along the outer shape of the winding portion, and the solder fillet can be reliably accommodated in the recessed portion.

[0041] Preferably, in one embodiment of the inductor component,

[0042] When viewed in the height direction, the inner surface of the recess is symmetrical with respect to the center of the recess in the width direction.

[0043] According to the above embodiment, since the shape of the green body is symmetrical, the green body has no directionality, thereby reducing deviations in the mounting arrangement of the inductor component when mounting the inductor component.

[0044] Preferably, in one embodiment of the inductor component,

[0045] The coil includes a winding portion wound in a spiral shape that overlaps each other when viewed from the axial direction, a first lead portion separated from the winding portion and connected to the first external electrode, and a second lead portion separated from the winding portion and connected to the second external electrode.

[0046] The shortest distance between the first external electrode and the outer shape of the winding portion is greater than 10 μm.

[0047] The shortest distance between the second external electrode and the outer shape of the winding portion is 10 μm or more.

[0048] According to the above embodiment, the shortest distance between the external electrode and the outer shape of the winding portion is at least 10 μm. Therefore, the external electrode is arranged at a predetermined distance from the winding portion. Even when the external electrode is placed in a recessed portion, short circuits between the external electrode and the winding portion caused by production variations can be reduced, thereby improving yield.

[0049] An electronic component as one embodiment of the present disclosure includes:

[0050] The inductor component described above; and

[0051] A mounting substrate is provided with a first pad and a second pad on a main surface of the mounting substrate.

[0052] The first external electrode of the inductor component is electrically connected to the first pad via solder, and the second external electrode is electrically connected to the second pad via solder.

[0053] In a direction perpendicular to the main surface of the mounting substrate, the first pad, the second pad, and the solder are not present between the coil and the main surface.

[0054] According to the above embodiment, no conductive material, such as pads or solder, exists between the coil and the main surface of the mounting substrate. Since there is no conductive material between the coil (which represents the external magnetic circuit) and the main surface of the mounting substrate, magnetic flux is less likely to be shielded. Consequently, the inductor component's L value acquisition efficiency and Q value can be further increased.

[0055] Preferably, in one embodiment of the electronic component, the electronic component comprises:

[0056] The inductor component described above; and

[0057] A mounting substrate is provided with a first pad and a second pad on a main surface of the mounting substrate.

[0058] The first external electrode of the inductor component is electrically connected to the first pad via solder, and the second external electrode is electrically connected to the second pad via solder.

[0059] When viewed from the axial direction, the first pad has a first outer end surface located on the opposite side of the second pad, and the second pad has a second outer end surface located on the opposite side of the first pad.

[0060] The length of the blank is greater than or equal to the distance between the first outer end surface and the second outer end surface.

[0061] According to the above embodiment, since the length of the base body is equal to or longer than the distance between the outer end surfaces of the two pads, the size of the inductor component can be increased relative to the mounting area.

[0062] According to the inductor component and the electronic component which are one embodiment of the present disclosure, the Q value can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a transparent perspective view showing a first embodiment of the inductor component.

[0064] Figure 2 This is an exploded perspective view of the inductor components.

[0065] Figure 3A is a cross-sectional view of the inductor component.

[0066] Figure 3B It is a cross-sectional view showing another embodiment of the inductor component.

[0067] Figure 3C It is a cross-sectional view showing another embodiment of the inductor component.

[0068] Figure 4 yes Figure 3A Magnified image of .

[0069] Figure 5A It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0070] Figure 5B It is an explanatory diagram for explaining a method of manufacturing an inductor component.

[0071] Figure 5C It is an explanatory diagram for explaining a method of manufacturing an inductor component.

[0072] Figure 5D It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0073] Figure 5E It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0074] Figure 5F It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0075] Figure 5G It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0076] Figure 5H It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0077] Figure 5I It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0078] Figure 5J It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0079] Figure 5K It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0080] Figure 5L It is an explanatory diagram for explaining a method for manufacturing an inductor component.

[0081] Figure 6 It is a cross-sectional view showing an electronic component on which an inductor component is mounted.

[0082] Figure 7A It is a plan view from the top surface showing another form of the recessed portion of the blank.

[0083] Figure 7B It is a plan view from the top surface showing another form of the recessed portion of the blank.

[0084] Figure 7C It is a plan view from the top surface showing another form of the recessed portion of the blank.

[0085] Figure 7D It is a plan view from the top surface showing another form of the recessed portion of the blank.

[0086] Description of Reference Numerals

[0087] 1…Inductor component; 7…Electronic component; 10, 10A to 10D…Body; 11…Insulating layer; 13…First side surface; 14…Second side surface; 15…First end surface; 16…Second end surface; 17…Bottom surface; 18…Top surface; 20…Coil; 20a…Axis; 21…First lead portion; 22…Second lead portion; 23…Wound portion; 23b…Outer shape; 24…Coil wiring; 241…First coil wiring; 242…Second coil wiring; 243…Third coil wiring; 244…Fourth coil wiring; 245…Fifth coil wiring; 25…Coil conductor Layer; 26…through-hole wiring; 30…first external electrode; 40…second external electrode; 50, 50A~50D…first recess; 50a…inner surface; 60, 60A~60D…second recess; 72…mounting substrate; 72a…main surface; 73…first solder pad; 731…first outer end surface; 74…second solder pad; 741…second outer end surface; 76…solder; D1~D5…depth of recess; dr…shortest distance between the external electrode and the outer shape of the winding portion; L…length of the blank; Lr…distance between the first outer end surface and the second outer end surface; r1~r5…inner diameter. DETAILED DESCRIPTION

[0088] Hereinafter, an inductor component and an electronic component as one embodiment of the present disclosure will be described in detail with reference to the illustrated embodiments. However, some drawings are schematic and may not reflect actual dimensions or proportions.

[0089] (First embodiment)

[0090] <Inductor Component Structure>

[0091] Figure 1 It is a transparent perspective view showing a first embodiment of the inductor component. Figure 2 This is an exploded perspective view of the inductor components. Figure 1 and Figure 2 As shown, the inductor component 1 includes: a base body 10, a coil 20 provided in the base body 10 and wound in a spiral shape along an axis, and a first external electrode 30 and a second external electrode 40 provided in the base body 10 and electrically connected to the coil 20. Figure 1 In the figure, the blank 10 is depicted as transparent to facilitate understanding of the structure, but it may also be translucent or opaque.

[0092] Inductor component 1 is electrically connected to wiring on a mounting substrate (not shown) via first and second external electrodes 30 and 40. Inductor component 1 is used, for example, as an impedance matching coil (matching coil) in high-frequency circuits and is used in electronic devices such as personal computers, DVD players, digital cameras, TVs, mobile phones, automotive electronics, and medical and industrial equipment. However, the applications of inductor component 1 are not limited to these; for example, it can also be used in tuning circuits, filter circuits, and rectifier and smoothing circuits.

[0093] The blank 10 is a rectangular parallelepiped having a length, a width, and a height, with the length being greater than the width and vice versa. As shown in the figure, the X direction is the length direction of the blank 10, the Y direction is the width direction of the blank 10, and the Z direction is the height direction of the blank 10. The X, Y, and Z directions are mutually orthogonal. The surface of the blank 10 includes a first end face 15 and a second end face 16 located at both ends of the length direction, a first side face 13 and a second side face 14 located at both ends of the width direction, and a bottom face 17 and a top face 18 located at both ends of the height direction.

[0094] The blank 10 is composed of a plurality of stacked insulating layers 11. The insulating layer 11 is composed of, for example, a material having borosilicate glass as a main component, ferrite, resin and other materials. The stacking direction of the insulating layer 11 is a direction (Y direction) parallel to the first end face 15, the second end face 16 and the bottom face 17 of the blank 10. That is, the insulating layer 11 is a layer extending along the XZ plane. The "parallel" in this application is not limited to a strict parallel relationship, and also includes a substantial parallel relationship taking into account the range of actual deviations. Among them, the blank 10 has a situation where the interfaces between the plurality of insulating layers 11 are unclear due to firing, etc.

[0095] The coil 20 is made of a conductive material such as Ag, Cu, Au, or an alloy primarily composed of these. The coil 20 is wound helically along the stacking direction of the insulating layer 11. A first end of the coil 20 is connected to the first external electrode 30, and a second end of the coil 20 is connected to the second external electrode 40. In this embodiment, the coil 20 is integrated with the first and second external electrodes 30 and 40, with no clear boundary. However, this is not limiting; boundaries may exist due to the coil and external electrodes being formed using different materials or methods.

[0096] The coil 20 is wound along an axis parallel to the width direction of the base body 10. That is, the axis of the coil 20 coincides with the stacking direction (Y direction) of the insulating layer 11. The axis of the coil 20 is the central axis of the spiral shape of the coil 20.

[0097] The coil 20 includes a winding portion 23, a first lead portion 21 connected between a first end of the winding portion 23 and a first external electrode 30, and a second lead portion 22 connected between a second end of the winding portion 23 and a second external electrode 40. In this embodiment, the winding portion 23 is integrated with the first and second lead portions 21 and 22 without a clear boundary. However, this is not limiting; a boundary may exist due to the winding portion and lead portions being formed using different materials or methods.

[0098] The winding portion 23 is wound in a spiral shape along the axis. Specifically, the winding portion 23 refers to the portion wound in a spiral shape that overlaps when viewed axially. The first lead portion 21 and the second lead portion 22 refer to the portions separated from the overlapping portion (the winding portion 23). While the winding portion 23 is formed into a generally rectangular shape when viewed axially, this shape is not limited to this. The winding portion 23 may also have a circular, elliptical, or other polygonal shape, for example.

[0099] The coil 20 includes a plurality of coil wirings 24 stacked along the axis, and a through-hole wiring 26 extending along the axis and connecting axially adjacent coil wirings 24. The plurality of coil wirings 24 are wound along a plane, electrically connected in series, and form a spiral.

[0100] The coil wiring 24 is formed by winding on the main surface (XZ plane) of the insulating layer 11 that is orthogonal to the axial direction. The winding amount of the coil wiring 24 is less than 1 turn, but it can also be more than 1 turn. The through-hole wiring 26 penetrates the insulating layer 11 in the thickness direction (Y direction). In addition, the coil wirings 24 adjacent to each other in the stacking direction are electrically connected in series via the through-hole wiring 26. In this way, the multiple coil wirings 24 are electrically connected in series to form a spiral. The coil wiring 24 is composed of a layer of coil conductor layer 25. In addition, the coil wiring 24 can also be composed of multiple coil conductor layers 25 that are in surface contact with each other.

[0101] The first external electrode 30 and the second external electrode 40 are made of, for example, the same conductive material as the coil 20. The first external electrode 30 is provided only on the first end surface 15. The first external electrode 30 is embedded in the base body 10 so as to be exposed from the first end surface 15. The second external electrode 40 is provided only on the second end surface 16. The second external electrode 40 is embedded in the base body 10 so as to be exposed from the second end surface 16.

[0102] As described above, since the external electrodes 30 and 40 are not provided on the top surface 18 and the bottom surface 17 of the base body, the flow of magnetic flux is not obstructed by the external electrodes 30 and 40. In addition, since the external electrodes 30 and 40 are not provided on the top surface 18 and the bottom surface 17, the inner diameter of the coil 20 can be increased accordingly on the top surface 18 side and the bottom surface 17 side.

[0103] In addition, “the external electrodes 30 and 40 are respectively provided only on the first end surface 15 and only on the second end surface 16” include the following Figure 2 The case where the lower ends of the external electrodes 30 and 40 are exposed at the bottom surface 17 as shown in the figure also includes the case where the upper ends of the external electrodes 30 and 40 are exposed at the top surface 18. However, in such a case, the external electrodes 30 and 40 do not have portions extending from the lower ends and the upper ends along the bottom surface 17 and the top surface 18, respectively.

[0104] The first external electrode 30 and the second external electrode 40 are constructed by stacking a plurality of first and second external electrode conductor layers 33 and 43 embedded in the base body 10 (insulating layer 11). The external electrode conductor layers 33 extend along the first end face 15, and the external electrode conductor layers 43 extend along the second end face 16. This allows the external electrodes 30 and 40 to be embedded within the base body 10, thereby reducing the size of the inductor component compared to a structure in which the external electrodes are attached to the base body 10. Furthermore, the coil 20 and the external electrodes 30 and 40 can be formed in the same process. This reduces variations in the positional relationship between the coil 20 and the external electrodes 30 and 40, thereby reducing variations in the electrical characteristics of the inductor component 1.

[0105] Figure 3A is a cross-sectional view of the inductor component. Figure 3A It is a cross-sectional view taken on an XY plane that includes the axis 20 a of the coil 20 and intersects the first external electrode 30 and the second external electrode 40 .

[0106] like Figure 3A As shown, the coil 20 has five layers of coil wiring 241 to 245. Specifically, the first coil wiring 241, the second coil wiring 242, the third coil wiring 243, the fourth coil wiring 244, and the fifth coil wiring 245 are arranged in sequence along the Y direction. That is, the third coil wiring 243 is located in the center portion of the coil 20 in the direction of the axis 20a. The first coil wiring 241 and the fifth coil wiring 245 are located at the two end portions of the coil 20 in the direction of the axis 20a. The second coil wiring 242 is located between the first coil wiring 241 and the third coil wiring 243. The fourth coil wiring 244 is located between the third coil wiring 243 and the fifth coil wiring 245.

[0107] like Figure 3A As shown, the inner diameter of the coil 20 is larger at both end portions in the direction of the axis 20a of the coil 20 than at the center portion in the direction of the axis 20a of the coil 20. The inner diameter of the coil 20 refers to the diameter of the inner side of the coil 20 in a cross section perpendicular to the axis 20a of the coil 20, and more specifically, the inner diameter of the winding portion 23 of the coil 20. In this embodiment, the coil 20 is formed into a substantially rectangular shape. Figure 3AIn the example, since the coil 20 is cut at the portion with the largest inner diameter, the inner diameters of the two end portions of the coil 20 are compared with the inner diameter of the central portion of the coil 20 based on the maximum inner diameter of the coil 20. Furthermore, although the comparison is based on the "maximum value" of the inner diameter of the coil 20, the comparison may also be based on the "minimum value" or "average value" so that the two end portions of the coil 20 are larger than the central portion of the coil 20.

[0108] Specifically, the inner diameter r1 of the first coil wiring 241 and the inner diameter r5 of the fifth coil wiring 245 are each larger than the inner diameter r3 of the third coil wiring 243. The inner diameter r1 of the first coil wiring 241 and the inner diameter r5 of the fifth coil wiring 245 are the same. Alternatively, the inner diameter r1 of the first coil wiring 241 and the inner diameter r5 of the fifth coil wiring 245 may be different.

[0109] The inner diameter r2 of the second coil wiring 242 and the inner diameter r4 of the fourth coil wiring 244 are respectively larger than the inner diameter r3 of the third coil wiring 243, and smaller than the inner diameter r1 of the first coil wiring 241 and the inner diameter r5 of the fifth coil wiring 245. The inner diameter r2 of the second coil wiring 242 and the inner diameter r4 of the fourth coil wiring 244 are the same. Alternatively, the inner diameter r2 of the second coil wiring 242 and the inner diameter r4 of the fourth coil wiring 244 may be different.

[0110] According to this embodiment, the inner diameter of the coil 20 is greater at both end portions in the direction of the axis 20a of the coil 20 than at the center portion in the direction of the axis 20a of the coil 20. Therefore, the coil 20 is configured to form a shape along which the magnetic flux diffuses outward from near the inner diameter of both end portions in the direction of the axis 20a of the coil 20. This can suppress the decrease in magnetic flux density around both end portions of the coil 20 (particularly, the area S1 axially outside the coil 20), thereby suppressing the decrease in inductance. Figure 3A , the magnetic flux lines are shown by dotted lines. As a result, current is less likely to concentrate at both ends of the coil 20, thus suppressing power loss. Thus, the inductor component 1 can improve the efficiency of obtaining the L value and increase the Q value.

[0111] exist Figure 3A In the example, since the number of coil wirings 241 to 245 is an odd number (five), the coil wiring located in the center portion of the coil 20 in the direction of the axis 20a is the third coil wiring 243. This allows the relationship between the inner diameter r3 of the central third coil wiring 243 and the inner diameter r1 of the first coil wiring 241 and the inner diameter r5 of the fifth coil wiring 245 at the ends to be determined.

[0112] On the other hand, when the number of coil wirings is even, the coil wiring located in the axial center of the coil constitutes two coil wirings. Therefore, the inner diameter of the coil wiring located at both ends of the coil in the axial direction need not be larger than the inner diameter of at least one of the two coil wirings located in the axial center of the coil.

[0113] like Figure 3A As shown, the inner diameter of the coil 20 increases continuously from the center of the coil 20 toward the ends of the coil 20. Specifically, the inner diameters of the multiple coil wirings 241 to 245 that comprise the coil 20 increase continuously from the central coil wiring 243 toward the end coil wirings 241 and 245. Specifically, the inner diameter r3 of the third coil wiring 243, the inner diameter r2 of the second coil wiring 242, and the inner diameter r1 of the first coil wiring 241 increase in that order. The inner diameter r3 of the third coil wiring 243, the inner diameter r4 of the fourth coil wiring 244, and the inner diameter r5 of the fifth coil wiring 245 increase in that order.

[0114] According to the above configuration, the inner peripheral surface of the coil 20 is shaped along the flow of magnetic flux, so that the flow of magnetic flux is less likely to be obstructed, and a decrease in magnetic flux density around both end portions of the coil 20 can be further suppressed.

[0115] In addition, the inner diameter of the coil 20 may also increase in a step-like manner from the center portion of the coil 20 toward the two end portions of the coil 20. That is, the inner diameters of the plurality of coil wirings 241 to 245 constituting the coil 20 may also increase in a step-like manner from the coil wiring 243 located in the center portion toward the coil wirings 241 and 245 located at the two end portions. For example, Figure 3B As shown, the inner diameter r3 of the third coil wiring 243 in the center is the same as the inner diameter r2 of the second coil wiring 242, and the inner diameter r1 of the first coil wiring 241 at the end is larger than the inner diameter r2 of the second coil wiring 242 and the inner diameter r3 of the third coil wiring 243. Alternatively, Figure 3C As shown, the inner diameter r1 of the first coil wiring 241 at the end is the same as the inner diameter r2 of the second coil wiring 242 , and the inner diameter r1 of the first coil wiring 241 and the inner diameter r2 of the second coil wiring 242 are larger than the inner diameter r3 of the third coil wiring 243 at the center.

[0116] According to the above configuration, since the inner diameter of the coil 20 changes in a stepwise manner along the axis 20 a direction, the coil 20 can be easily manufactured and the L value can be easily adjusted.

[0117] like Figure 1 and Figure 3AAs shown, the first end surface 15 of the blank 10 has a first recess 50, and the second end surface 16 of the blank 10 has a second recess 60. The first recess 50 and the second recess 60 are open at the bottom surface 17 and the top surface 18, respectively. The first recess 50 and the second recess 60 may also be open only at the bottom surface 17 and not at the top surface 18. The first external electrode 30 is provided in the first recess 50 of the first end surface 15. The second external electrode 40 is provided in the second recess 60 of the second end surface 16.

[0118] According to the above structure, Figure 6 As shown, when the inductor component 1 is mounted on a mounting substrate 72 having a first solder pad 73 and a second solder pad 74 arranged on its main surface 72a, solder 76 forms a solder fillet, electrically connecting the first solder pad 73 of the mounting substrate 72 to the first external electrode 30 of the inductor component 1, and the second solder pad 74 of the mounting substrate 72 to the second external electrode 40 of the inductor component 1. In this case, since the external electrodes 30 and 40 are located in the recesses 50 and 60, a solder fillet corresponding to the recesses 50 and 60 can be formed inside the base body 10. Forming the solder fillet to fit within the recesses 50 and 60 of the external electrodes 30 and 40 allows the size of the inductor component 1 to be increased relative to the mounting area. Here, the mounting area refers to the area of the smallest rectangle on the main surface 72a of the mounting substrate 72, including the first solder pad 73 and the second solder pad 74.

[0119] Furthermore, the above configuration allows the size of the inductor component 1 to be increased relative to the mounting area, thereby increasing the inner diameter of the coil 20 and thereby increasing the L value. Furthermore, by arranging the coil 20 at a distance from the external electrodes 30 and 40, parasitic capacitance can be reduced. This allows for a design that improves the Q value.

[0120] Figure 4 yes Figure 3A The first external electrode 30 and the first recess 50 are enlarged. Figure 4 The structure of the first recessed portion 50 will be described. Since the structure of the second recessed portion 60 is the same as that of the first recessed portion 50 , the description of the second recessed portion 60 will be omitted.

[0121] like Figure 4 As shown, the depths D1 to D5 of the first recess 50 along the X-direction preferably increase toward the center (center line C) of the first recess 50 in the Y-direction. Specifically, the first recess 50 includes a first portion 51, a second portion 52, a third portion 53, a fourth portion 54, and a fifth portion 55 arranged in sequence along the Y-direction. The third portion 53 is located in the center of the first recess 50 in the Y-direction. The first portion 51 and the fifth portion 55 are located at both ends of the first recess 50 in the Y-direction.

[0122] The first portion 51 is opposite to the first coil wiring 241 in the X direction. The second portion 52 is opposite to the second coil wiring 242 in the X direction. The third portion 53 is opposite to the third coil wiring 243 in the X direction. The fourth portion 54 is opposite to the fourth coil wiring 244 in the X direction. The fifth portion 55 is opposite to the fifth coil wiring 245 in the X direction.

[0123] The depth D1 of the first portion 51 and the depth D5 of the fifth portion 55 are respectively less than the depth D3 of the third portion 53. The depth D1 of the first portion 51 and the depth D5 of the fifth portion 55 are the same. Alternatively, the depth D1 of the first portion 51 and the depth D5 of the fifth portion 55 may be different.

[0124] The depth D2 of the second portion 52 and the depth D4 of the fourth portion 54 are each less than the depth D3 of the third portion 53, and greater than the depth D1 of the first portion 51 and the depth D5 of the fifth portion 55. The depth D2 of the second portion 52 and the depth D4 of the fourth portion 54 are the same. Alternatively, the depth D2 of the second portion 52 and the depth D4 of the fourth portion 54 may be different.

[0125] According to this embodiment, the depths D1 to D5 of the first recess 50 along the X direction increase toward the center of the first recess 50 in the Y direction. Therefore, when the inductor component 1 is mounted on a mounting substrate, the contact area (fixed area) with the solder increases compared to inductor components with planar end faces, and the proportion of the fixed area to the solder surface area increases. Consequently, a joint with high fixing strength can be formed using a small amount of solder.

[0126] like Figure 4 As shown, the depths D1 to D5 of the first recess 50 along the X-direction preferably increase in a stepped manner toward the center of the first recess 50 in the Y-direction. Specifically, the first portion 51 to the fifth portion 55 each have a constant depth D1 to D5 along the Y-direction. In other words, the inner surface 50a of the first recess 50 is formed in a stepped shape.

[0127] With the above configuration, when the inductor component 1 is formed layer by layer and stacked for manufacturing, the coil 20 and the first recess 50 can be formed simultaneously, thereby improving workability, reducing the number of steps, and lowering costs.

[0128] like Figure 4 As shown, preferably, when viewed from the Z direction, the inner surface 50a of the first recess 50 is along the outer shape 23b of the winding portion 23 of the coil 20. The outer shape 23b of the winding portion 23 is the direction perpendicular to the axial direction of the coil 20 ( Figure 4The inner surface 50a being along the outer shape 23b not only means that the inner surface 50a is completely consistent with the outer shape 23b, but also includes the case where the inner surface 50a is almost consistent with the outer shape 23b.

[0129] According to the above configuration, the first recess 50 can be enlarged to the maximum extent along the outer shape 23 b of the winding portion 23 , and the solder fillet can be reliably accommodated in the first recess 50 .

[0130] like Figure 4 As shown, preferably, when viewed from the Z direction, the inner surface 50a of the first recess 50 is symmetrical with respect to the center (center line C) of the first recess 50 in the Y direction. That is, the first portion 51 and the fifth portion 55 have the same shape, the second portion 52 and the fourth portion 54 have the same shape, and the shape of the third portion 53 is symmetrical with respect to the center line C.

[0131] According to the above configuration, since the shape of the green body 10 is symmetrical, the green body 10 has no directionality. Therefore, when the inductor component 1 is mounted, deviations in the mounting arrangement of the inductor component 1 can be reduced.

[0132] like Figure 4 As shown, the shortest distance dr between the first external electrode 30 and the outer shape 23b of the wound portion 23 is preferably 10 μm or greater. With this configuration, since the first external electrode 30 is spaced at least a predetermined distance from the wound portion 23, even when the first external electrode 30 is positioned in the first recess 50, short circuits between the first external electrode 30 and the wound portion 23 caused by production variations can be reduced, thereby improving yield. Although not shown, the shortest distance between the second external electrode 40 and the outer shape 23b of the wound portion 23 is also preferably 10 μm or greater.

[0133] <Method for Manufacturing Inductor Components>

[0134] Next, use Figures 5A to 5L A method for manufacturing the inductor component 1 will be described. Hereinafter, a method for manufacturing the recessed portions 50 and 60 and the external electrodes 30 and 40 of the base body 10 will be described in particular, and a method for manufacturing the coil 20 (coil wiring 24) will be omitted.

[0135] like Figure 5AAs shown, a temporary filling layer 102, a marking layer 100, a first unfired insulating layer 111 and a second unfired insulating layer 112 are stacked on an alumina substrate 104. The temporary filling layer 102 is made of a material that disappears when fired, for example, the main component of which is an organic resin. The unfired insulating layers 111 and 112 are the state of the insulating layer 11 before firing, for example, they are made of a material with borosilicate glass as the main component. In addition to the same material as the unfired insulating layer 111, the marking layer 100 also contains a pigment material. The marking layer 100 is not a necessary structure and can be omitted. In addition, Figures 1 to 4 In the inductor component 1 described in , the marking layer 100 is omitted.

[0136] like Figure 5B As shown, the second unfired insulating layer 112 is exposed and developed to form a groove pattern in the second unfired insulating layer 112. At this time, the X-direction dimension of the second unfired insulating layer 112 is formed to be smaller than the X-direction dimension of the first unfired insulating layer 111.

[0137] like Figure 5C As shown, a metal film 106 is printed to fill the groove. Metal film 106 is the pre-firing state of external electrodes 30 and 40 and is composed, for example, of a conductive material primarily composed of Ag. Although not illustrated, coil 20 is formed simultaneously with external electrodes 30 and 40 using metal film 106.

[0138] like Figure 5D As shown, the metal film 106 is exposed and developed to form a desired shape. Figure 5E As shown, a temporary filling layer 102 is printed, as shown Figure 5F As shown, the temporary filling layer 102 is exposed and developed to form a desired shape, so that the second unfired insulating layer 112 and the metal film 106 are exposed.

[0139] like Figure 5G As shown, the third unfired insulating layer 113 is printed, as shown in FIG. Figure 5H As shown, the third unfired insulating layer 113 is exposed and developed to form a desired shape to expose the metal film 106. At this time, the X-direction dimension of the third unfired insulating layer 113 is formed to be smaller than the X-direction dimension of the second unfired insulating layer 112.

[0140] like Figure 5I As shown, a metal film 106 is further printed to fill the groove. Figure 5J As shown, the metal film 106 is exposed and developed to expose the third unfired insulating layer 113 and the temporary filling layer 102 .

[0141] Repeat these steps, such as Figure 5KAs shown, a fourth unfired insulating layer 114, a fifth unfired insulating layer 115, a sixth unfired insulating layer 116, and a seventh unfired insulating layer 117 are formed to form a mother laminate.

[0142] At this time, the fourth unfired insulating layer 114 is formed to have a smaller dimension in the X direction than the third unfired insulating layer 113, the fifth unfired insulating layer 115 is formed to have a larger dimension in the X direction than the fourth unfired insulating layer 114, the sixth unfired insulating layer 116 is formed to have a larger dimension in the X direction than the fifth unfired insulating layer 115, and the seventh unfired insulating layer 117 is formed to have a larger dimension in the X direction than the sixth unfired insulating layer 116. In this way, the recesses 50 and 60 are formed by utilizing the deviation between the first to seventh unfired insulating layers 111 to 117. The metal film 106 is then formed in these recesses 50 and 60.

[0143] Then, the mother laminate is cut into a plurality of unfired laminates by cutting or the like, and the plurality of unfired laminates are fired, such as Figure 5L As shown, a plurality of inductor components 1 are obtained, each including the green body 10 and the external electrodes 30 , 40 . The temporary filling layer 102 is burned away by firing, and the external electrodes 30 , 40 are provided in the recesses 50 , 60 .

[0144] <Structure of electronic components>

[0145] Figure 6 is a cross-sectional view of an electronic component. Figure 6 As shown, the electronic component 7 includes the inductor component 1 and a mounting substrate 72. The mounting substrate 72 has a main surface 72a thereof on which first pads 73 and second pads 74 are arranged.

[0146] The first external electrode 30 of the inductor component 1 is electrically connected to the first pad 73 via the solder 76 . The second external electrode 40 of the inductor component 1 is electrically connected to the second pad 74 via the solder 76 .

[0147] In a direction perpendicular to the main surface 72a of the mounting substrate 72, the first solder pad 73, the second solder pad 74, and the solder 76 are not present between the coil 20 (coil wiring 24) and the main surface 72a. Specifically, the main surface 72a is parallel to the XY plane, and the first solder pad 73, the second solder pad 74, and the solder 76 are not present between the coil 20 and the main surface 72a in the Z direction.

[0148] With the above configuration, no conductive material, such as pads 73 and 74 or solder 76, exists between coil 20 and main surface 72a. This eliminates the need for conductive material between coil 20, which corresponds to the external magnetic path, and main surface 72a, making it less likely that magnetic flux will be blocked. This further increases the efficiency of obtaining the L value and the Q value of inductor component 1.

[0149] like Figure 6 As shown, when viewed from the axis 20a of the coil 20, the first solder pad 73 has a first outer end face 731 located on the opposite side of the second solder pad 74, and the second solder pad 74 has a second outer end face 741 located on the opposite side of the first solder pad 73, and the length L of the blank 10 is greater than the distance Lr between the first outer end face 731 and the second outer end face 741.

[0150] According to the above configuration, since the length L of the base body 10 is equal to or greater than the distance Lr between the outer end surfaces 731 and 741 of the two pads 73 and 74 , the size of the inductor component 1 can be increased relative to the mounting area.

[0151] In addition, in the electronic component 7 of this embodiment, there is a first structure in which "the first solder pad 73, the second solder pad 74 and the solder 76 do not exist between the coil 20 and the main surface 72a" and a second structure in which "the length L of the blank 10 is greater than the distance Lr between the outer end surfaces 731 and 741 of the two solder pads 73 and 74", but it is sufficient to have at least one of the first structure and the second structure.

[0152] (Second embodiment)

[0153] Figures 7A to 7D This is a top view showing another embodiment of the recessed portion of the blank. The second embodiment differs from the first embodiment in the shape of the recessed portion of the blank. This difference is described below. The remaining structures are identical to those of the first embodiment and are denoted by the same reference numerals as those of the first embodiment, and their descriptions are omitted.

[0154] like Figure 7A As shown, in the first recess 50A of the blank 10A, the depth of the first recess 50A in the X direction continuously increases toward the center of the first recess 50A in the Y direction. Specifically, the inner surface 50a of the first recess 50A is formed into a V shape when viewed from the Z direction.

[0155] According to the above structure, when forming the first recess 50A, the first recess 50A can be easily formed by forming the rectangular blank 10A and then cutting the flat first end surface 15 into a V shape by cutting or the like.

[0156] like Figure 7B As shown, in the first recess 50B of the blank 10B, the depth of the first recess 50B in the X direction continuously increases toward the center of the first recess 50B in the Y direction. Specifically, the inner surface 50a of the first recess 50B is formed in a semicircular shape when viewed from the Z direction.

[0157] According to the above structure, when forming the first recess 50B, the first recess 50B can be easily formed by utilizing the shrinkage caused by firing during the firing process of the blank 10B. The same structure applies to the second recess 60B.

[0158] like Figure 7C As shown, in the first recess 50C of the blank 10C, the depth of the first recess 50C in the X direction is constant in the Y direction. Specifically, the inner surface 50a of the first recess 50C is formed in a rectangular shape when viewed from the Z direction.

[0159] According to the above configuration, since the shape of the first recess 50C is simple, the first recess 50C can be easily formed. The configuration of the second recess 60C is also the same.

[0160] like Figure 7D As shown, in the first recess 50D of the blank 10D, the depth of the first recess 50D in the X direction continuously increases toward the center of the first recess 50B in the Y direction and then becomes constant. Specifically, the inner surface 50a of the first recess 50D is formed into a trapezoidal shape when viewed from the Z direction.

[0161] According to the above structure, since the volume of the first recess 50D can be reduced, the volume of the base body 10D can be increased, and the reduction in inductance can be suppressed. The structure of the second recess 60D is also the same.

[0162] In addition, the present disclosure is not limited to the above-mentioned embodiments, and design changes can be made within the scope of the main purpose of the present disclosure. For example, various combinations of the various features of the first embodiment and the second embodiment can be made. Specifically, the number of coils and the number of external electrodes can be increased, and the number of coil wirings constituting the coil can be increased or decreased. In addition, the shapes of the first recess and the second recess are the same, but can also be different, and can also be any shape. In addition, only one of the first recess and the second recess can be provided, or both the first recess and the second recess can be omitted.

[0163] In the above embodiment, the axis of the coil is perpendicular to the side surface of the blank, but may be perpendicular to the end surface of the blank or may be perpendicular to the bottom surface of the blank.

[0164] In the above embodiment, the external electrode is provided only in the concave portion of the end surface, but may be provided continuously in the concave portion of the end surface and the bottom surface, or may be provided continuously in the concave portion of the end surface, the bottom surface, and the top surface.

[0165] (Example)

[0166] Hereinafter, an embodiment of a method for manufacturing the inductor component 1 will be described.

[0167] First, an insulating paste primarily composed of borosilicate glass is repeatedly applied to a base material, such as a carrier film, through screen printing to form an insulating layer. This insulating layer serves as an outer insulating layer, located outside the coil conductor layer. Furthermore, the base material can be removed from the insulating layer at any stage, leaving no residue in the inductor component.

[0168] Then, a photosensitive conductive paste layer is applied on the insulating layer, and a coil conductor layer and an external electrode conductor layer are formed through a photolithography process. Specifically, a photosensitive conductive paste containing Ag as the main metal component is applied to the insulating layer by screen printing to form the photosensitive conductive paste layer. Furthermore, the photosensitive conductive paste layer is irradiated with ultraviolet light or the like through a photomask and developed with an alkaline solution or the like. Thus, a coil conductor layer and an external electrode conductor layer are formed on the insulating layer. At this point, the coil conductor layer and the external electrode conductor layer can be traced into the desired pattern using a photomask.

[0169] Next, a photosensitive insulating paste layer is applied to the insulating layer, and a photolithography process is performed to form the insulating layer with openings and through-holes. Specifically, the photosensitive insulating paste is applied to the insulating layer by screen printing to form the photosensitive insulating paste layer. Furthermore, the photosensitive insulating paste layer is irradiated with ultraviolet light, etc., through a photomask and developed with an alkaline solution, etc. At this point, the photosensitive insulating paste layer is patterned using the photomask to provide openings above the external electrode conductor layer and through-holes at the ends of the coil conductor layer.

[0170] Then, a photosensitive conductive paste layer is applied on the insulating layer provided with openings and through-holes, and a coil conductor layer and an external electrode conductor layer are formed by a photolithography process. Specifically, a photosensitive conductive paste having Ag as the main metal component is applied to the insulating layer by screen printing to fill the openings and through-holes, thereby forming a photosensitive conductive paste layer. Furthermore, the photosensitive conductive paste layer is irradiated with ultraviolet light or the like through a photomask and developed with an alkaline solution or the like. Thus, an external electrode conductor layer connected to the external electrode conductor layer on the lower layer side via the opening and a coil conductor layer connected to the coil conductor layer on the lower layer side via the through-hole are formed on the insulating layer.

[0171] By repeatedly performing the steps of forming an insulating layer, a coil conductor layer, and an external electrode conductor layer as described above, a coil composed of a coil conductor layer formed on a plurality of insulating layers and an external electrode composed of an external electrode conductor layer formed on a plurality of insulating layers are formed. Furthermore, on the insulating layer on which the coil and the external electrode are formed, an insulating layer is formed by repeatedly applying an insulating paste by screen printing. This insulating layer becomes an outer insulating layer located on the outside of the coil conductor layer. By changing the width dimensions of the plurality of insulating layers and providing a step difference in the plurality of insulating layers, a stepped recess is formed on the end face of the blank composed of the plurality of insulating layers. The external electrode is provided in the recess. In addition, if the group of coils and external electrodes is formed in a matrix on the insulating layer in the above steps, a mother laminate can be obtained.

[0172] The mother laminate is then cut into a plurality of unfired laminates by dicing or other means. During the mother laminate cutting step, the external electrodes are exposed from the mother laminate at the cut surfaces formed by the cutting. If a certain amount of cutting deviation occurs during this process, the outer periphery of the coil conductor layer formed in the above step may appear on the end surface or bottom surface.

[0173] The unfired laminate is then fired under specified conditions to obtain a green body containing the coil and external electrodes. This green body is then barrel-polished to the desired dimensions. The exposed portions of the external electrodes are then plated with Ni to a thickness of 2 to 10 μm and Sn to a thickness of 2 to 10 μm. This completes the inductor component, measuring 0.4 mm x 0.2 mm x 0.2 mm.

[0174] Furthermore, the method for forming a conductor pattern is not limited to the above-described method. For example, a method of printing and laminating a conductor paste using a screen with openings in the shape of the conductor pattern may also be employed. Alternatively, a method of patterning a conductor film formed by sputtering, vapor deposition, or foil crimping may be employed. Alternatively, a method of removing unnecessary portions after forming a negative pattern and forming a conductor pattern by plating, as in a semi-additive method, may be employed. Furthermore, achieving a high aspect ratio by forming a conductor pattern in multiple stages can reduce losses caused by resistance at high frequencies. More specifically, the above-described conductor pattern formation may be repeated, or a process may be employed in which wiring formed by a semi-additive process is repeatedly overlapped, or a process may be employed in which a portion of the stack is formed by a semi-additive process and the remaining portion is formed by etching a film grown by plating, or a process may be employed in which wiring formed by a semi-additive process is further grown by plating to achieve a high aspect ratio.

[0175] Furthermore, the conductive material is not limited to the Ag paste described above; any good conductor such as Ag, Cu, or Au formed by sputtering, vapor deposition, foil crimping, plating, etc., can be used. Furthermore, the method for forming the insulating layer and the openings and through-holes is not limited to the above methods; alternative methods include crimping, spin coating, or spraying an insulating material sheet followed by laser or drilling to create the openings.

[0176] In addition, the insulating material is not limited to the glass and ceramic materials mentioned above, and may be an organic material such as epoxy resin, fluororesin, or polymer resin, or a composite material such as glass epoxy resin. However, a material with a small dielectric constant and dielectric loss is preferred.

[0177] The dimensions of the inductor components are not limited to the above dimensions. Furthermore, the method for forming the external electrodes is not limited to plating the external conductors exposed by cutting. A method may also be employed in which, after cutting, the external electrodes are further formed by dipping or sputtering a conductive paste, and then plating is performed on the external electrodes.

Claims

1. An inductor component comprising: green body; a coil, disposed in the blank and wound along the axial direction; and a first external electrode and a second external electrode, the first external electrode and the second external electrode being provided on the base body and electrically connected to the coil; Regarding the inner diameter of the coil, the inner diameters of the two end portions of the coil in the axial direction are larger than the inner diameter of the central portion of the coil in the axial direction. The blank is in the shape of a rectangular parallelepiped having a length, a width, and a height, wherein the length is greater than the width and the length is greater than the height. The blank comprises a first end face and a second end face located at both ends of the length direction, a first side face and a second side face located at both ends of the width direction, and a bottom face and a top face located at both ends of the height direction. The axis of the coil is parallel to the width direction. The first external electrode is only provided on the first end surface, and the second external electrode is only provided on the second end surface. The first end surface and the second end surface each have a recessed portion. The recessed portion opens at the bottom surface. The first external electrode is provided in the recessed portion of the first end surface. The second external electrode is provided in the recessed portion of the second end surface.

2. The inductor component according to claim 1, wherein The inner diameter of the coil continuously increases from the central portion of the coil toward both end portions of the coil.

3. The inductor component according to claim 1, wherein The inner diameter of the coil increases in a step-like manner from the central portion of the coil toward both end portions of the coil.

4. The inductor component according to any one of claims 1 to 3, wherein The depth of the recessed portion along the longitudinal direction increases toward the center of the recessed portion in the width direction.

5. The inductor component according to claim 4, wherein The depth of the recessed portion along the longitudinal direction increases in a step-like manner toward the center of the recessed portion in the width direction.

6. The inductor component according to any one of claims 1 to 3, wherein The coil includes a winding portion wound in a spiral shape that overlaps each other when viewed from the axial direction, a first lead portion separated from the winding portion and connected to the first external electrode, and a second lead portion separated from the winding portion and connected to the second external electrode. When viewed from the height direction, the inner surface of the recessed portion follows the outer shape of the wound portion.

7. The inductor component according to any one of claims 1 to 3, wherein When viewed in the height direction, the inner surface of the recess is symmetrical with respect to the center of the recess in the width direction.

8. The inductor component according to any one of claims 1 to 3, wherein The coil includes a winding portion wound in a spiral shape that overlaps each other when viewed from the axial direction, a first lead portion separated from the winding portion and connected to the first external electrode, and a second lead portion separated from the winding portion and connected to the second external electrode. The shortest distance between the first external electrode and the outer shape of the winding portion is greater than 10 μm. The shortest distance between the second external electrode and the outer shape of the winding portion is 10 μm or more.

9. An electronic component comprising: The inductor component according to any one of claims 1 to 3; and A mounting substrate is provided with a first pad and a second pad on a main surface of the mounting substrate. The first external electrode of the inductor component is electrically connected to the first pad via solder, and the second external electrode is electrically connected to the second pad via solder. In a direction perpendicular to the main surface of the mounting substrate, the first pad, the second pad, and the solder are not present between the coil and the main surface.

10. An electronic component comprising: The inductor component according to any one of claims 1 to 3; and A mounting substrate is provided with a first pad and a second pad on a main surface of the mounting substrate. The first external electrode of the inductor component is electrically connected to the first pad via solder, and the second external electrode is electrically connected to the second pad via solder. When viewed from the axial direction, the first pad has a first outer end surface located on the opposite side of the second pad, and the second pad has a second outer end surface located on the opposite side of the first pad. The length of the blank is greater than or equal to the distance between the first outer end surface and the second outer end surface.

Images