printed wiring board

Abstract

A coil device with improved inductance characteristics is provided. [Solution] The coil device includes a base film, a first wiring, and a second wiring. The base film has a first main surface and a second main surface. The first wiring has a first winding portion disposed on the first main surface and wound spirally in a plan view, and a second winding portion disposed on the second main surface and wound spirally in a plan view. The second wiring has a third winding portion disposed on the first main surface and wound spirally in a plan view, and a fourth winding portion disposed on the second main surface and wound spirally in a plan view.

Description

[Technical Field]

[0001] The present disclosure relates to printed wiring boards. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2021-68828 (Patent Document 1) describes a coil device. The coil device described in Patent Document 1 has a substrate, a first winding portion, a second winding portion, a third winding portion, and a fourth winding portion.

[0003] The substrate has a first main surface and a second main surface opposite the first main surface. The first winding portion and the second winding portion are disposed on the first main surface. The third winding portion and the fourth winding portion are disposed on the second main surface. In the first winding portion, the second winding portion, the third winding portion, and the third winding portion, wiring is wound in a spiral shape in a plan view. The wiring forming the first winding portion is alternately arranged with the wiring forming the second winding portion in a direction from the inner circumference toward the outer circumference of the first winding portion. The wiring forming the third winding portion is alternately arranged with the wiring forming the fourth winding portion in a direction from the inner circumference toward the outer circumference of the third winding portion. The innermost circumference of the first winding portion is electrically connected to the innermost circumference of the third winding portion, and the innermost circumference of the second winding portion is electrically connected to the innermost circumference of the fourth winding portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-68828 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is room for improvement in the inductance characteristics of the coil device described in Patent Document 1. The present disclosure provides a coil device with improved inductance characteristics. [Means for solving the problem]

[0006] The coil device of the present disclosure includes a base film, a first wiring, and a second wiring. The base film has a first main surface and a second main surface. The first wiring has a first winding portion disposed on the first main surface and wound spirally in a plan view, and a second winding portion disposed on the second main surface and wound spirally in a plan view. The second wiring has a third winding portion disposed on the first main surface and wound spirally in a plan view, and a fourth winding portion disposed on the second main surface and wound spirally in a plan view. The portion of the first wiring in the first winding portion is alternately arranged with the portion of the second wiring in the third winding portion in a direction from the inner periphery to the outer periphery of the first winding portion, and overlaps with the portion of the second wiring in the fourth winding portion in a plan view. The portion of the first wiring in the second winding portion is arranged alternately with the portion of the second wiring in the fourth winding portion in the direction from the inner circumference to the outer circumference of the second winding portion, and overlaps with the portion of the second wiring in the third winding portion in a planar view. [Effects of the Invention]

[0007] According to the coil device of the present disclosure, the inductance characteristics are improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a first plan view of the coil device 100. FIG. [Figure 2] FIG. 2 is a second plan view of the coil device 100 as seen from the opposite side to that of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a manufacturing process diagram of the coil device 100. [Figure 5] FIG. 5 is an explanatory diagram of the preparation step S1. [Figure 6] FIG. 6 is an explanatory diagram of the electroless plating step S3. [Figure 7] FIG. 7 is an explanatory diagram of the resist pattern forming step S4. [Figure 8] FIG. 8 is an explanatory diagram of the electrolytic plating step S5. [Figure 9] FIG. 9 is an explanatory diagram of the resist pattern removing step S6. [Figure 10] FIG. 10 is a first plan view of the coil device 200. As shown in FIG. [Figure 11] FIG. 11 is a second plan view of the coil device 200 as seen from the opposite side to that of FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 13 is a first plan view of the coil device 300. As shown in FIG. [Figure 14] FIG. 14 is a second plan view of the coil device 300 as seen from the opposite side to that of FIG. [Figure 15] FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. [Figure 16] FIG. 16 is a graph showing the relationship between the transmission loss and frequency in the differential mode in the coil device 100 and the coil device 300. In FIG. [Figure 17] FIG. 17 is a graph showing the relationship between the transmission loss in the common mode and the frequency in the coil device 100 and the coil device 300. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A coil device according to an embodiment includes a base film, a first wiring, and a second wiring. The base film has a first main surface and a second main surface. The first wiring has a first winding portion disposed on the first main surface and wound spirally in a plan view, and a second winding portion disposed on the second main surface and wound spirally in a plan view. The second wiring has a third winding portion disposed on the first main surface and wound spirally in a plan view, and a fourth winding portion disposed on the second main surface and wound spirally in a plan view. A portion of the first wiring in the first winding portion is alternately arranged with a portion of the second wiring in the third winding portion in a direction from the inner periphery to the outer periphery of the first winding portion, and overlaps with a portion of the second wiring in the fourth winding portion in a plan view. The portions of the first wiring in the second winding portion are alternately arranged with the portions of the second wiring in the fourth winding portion in the direction from the inner circumference toward the outer circumference of the second winding portion, and overlap with the portions of the second wiring in the third winding portion in a plan view. According to the coil device of (1) above, the inductance characteristics are improved.

[0011] (2) In the coil device of (1) above, the first wiring may have a first external connection terminal and a first land arranged on the first main surface, and a second external connection terminal and a second land arranged on the second main surface. The first external connection terminal and the first land may be connected to the outermost and innermost peripheries of the first winding portion, respectively. The second external connection terminal and the second land may be connected to the outermost and innermost peripheries of the second winding portion, respectively. The first land and the second land may overlap in a plan view. The second wiring may have a third external connection terminal and a third land arranged on the first main surface, and a fourth external connection terminal and a fourth land arranged on the second main surface. The third external connection terminal and the third land may be connected to the outermost and innermost peripheries of the third winding portion, respectively. The fourth external connection terminal and the fourth land may be connected to the outermost and innermost peripheries of the fourth winding portion, respectively. The third land and the fourth land may overlap in a plan view. The coil device of (2) above can be made low-profile.

[0012] (3) In the coil device of (1) or (2) above, the distance between the portion of the first wiring in the first winding section and the portion of the second wiring in the third winding section that are adjacent to each other may be 20 μm or less, and the distance between the portion of the first wiring in the second winding section and the portion of the second wiring in the fourth winding section that are adjacent to each other may be 20 μm or less.

[0013] (4) In the coil device of (1) to (3) above, the width of the portion of the first wiring in the first winding portion and the width of the portion of the first wiring in the second winding portion may be 20 μm or less. The width of the portion of the second wiring in the third winding portion and the width of the portion of the second wiring in the fourth winding portion may be 20 μm or less.

[0014] [Details of the embodiments of the present disclosure] Next, details of an embodiment of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and redundant description will not be repeated. The coil device according to the embodiment is referred to as coil device 100.

[0015] (Configuration of coil device 100) The configuration of the coil device 100 will be described below.

[0016] FIG. 1 is a first plan view of the coil device 100. FIG. 2 is a second plan view of the coil device 100 as viewed from the opposite side to that of FIG. 1. In FIGS. 1 and 2, the wiring 20 is cross-hatched to clearly distinguish between the wiring 20 and the wiring 30. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. As shown in FIGS. 1, 2, and 3, the coil device 100 has a base film 10, wiring 20, and wiring 30.

[0017] The base film 10 has a main surface 10a and a main surface 10b. The main surface 10b is the surface opposite to the main surface 10a. The main surfaces 10a and 10b are end surfaces of the base film 10 in the thickness direction. The base film 10 is formed, for example, from a flexible, electrically insulating material. A specific example of a constituent material of the base film 10 is polyimide.

[0018] The wiring 20 has a first winding portion 21 and a second winding portion 22. The first winding portion 21 is disposed on the main surface 10a. The second winding portion 22 is disposed on the main surface 10b. In the first winding portion 21, the wiring 20 is wound in a spiral shape in a planar view. In the second winding portion 22, the wiring 20 is wound in a spiral shape in a planar view. Note that a planar view refers to a case where the coil device 100 is viewed along the normal direction to the main surface 10a or the normal direction to the main surface 10b.

[0019] The wiring 20 further has a first external connection terminal 23, a first land 24, a second land 25, and a second external connection terminal 26. The first external connection terminal 23 is arranged on the main surface 10a and is connected to the outermost periphery of the first winding portion 21. The first land 24 is arranged on the main surface 10a and is connected to the innermost periphery of the first winding portion 21. The second land 25 is arranged on the main surface 10b and is arranged at the innermost periphery of the second winding portion 22. The second external connection terminal 26 is arranged on the main surface 10b and is arranged at the outermost periphery of the second winding portion 22. The first land 24 and the second land 25 overlap in a plan view.

[0020] The wiring 30 has a third winding portion 31 and a fourth winding portion 32. The third winding portion 31 is disposed on the main surface 10a. The fourth winding portion 32 is disposed on the main surface 10b. In the third winding portion 31, the wiring 30 is wound in a spiral shape in a plan view. In the fourth winding portion 32, the wiring 30 is wound in a spiral shape in a plan view.

[0021] The wiring 30 further has a third external connection terminal 33, a third land 34, a fourth land 35, and a fourth external connection terminal 36. The third external connection terminal 33 is disposed on the main surface 10a and is connected to the outermost periphery of the third winding portion 31. The third land 34 is disposed on the main surface 10a and is connected to the innermost periphery of the third winding portion 31. The fourth land 35 is disposed on the main surface 10b and is disposed at the innermost periphery of the fourth winding portion 32. The fourth external connection terminal 36 is disposed on the main surface 10b and is disposed at the outermost periphery of the fourth winding portion 32. The third land 34 and the fourth land 35 overlap in a plan view.

[0022] The portions of wiring 20 in first winding portion 21 are arranged alternately with the portions of wiring 30 in third winding portion 31 in the direction from the inside to the outside of first winding portion 21. The direction from the inside to the outside of first winding portion 21 is a direction perpendicular to the direction in which the portions of wiring 20 in first winding portion 21 extend in a planar view. Note that when the portions of wiring 20 in first winding portion 21 extend in a curved shape in a planar view, the extension direction of the portions of wiring 20 in first winding portion 21 is defined as the tangent direction of the curved shape.

[0023] The portions of the wiring 20 in the second winding portion 22 are alternately arranged with the portions of the wiring 30 in the fourth winding portion 32 in the direction from the inside to the outside of the second winding portion 22. The direction from the inside to the outside of the second winding portion 22 is a direction perpendicular to the direction in which the portions of the wiring 20 in the second winding portion 22 extend in a planar view. Note that when the portions of the wiring 20 in the second winding portion 22 extend in a curved shape in a planar view, the extension direction of the portions of the wiring 20 in the second winding portion 22 is defined as the tangent direction of the curved shape.

[0024] In plan view, the portion of wiring 20 in first winding portion 21 overlaps with the portion of wiring 30 in fourth winding portion 32. In plan view, the portion of wiring 20 in second winding portion 22 overlaps with the portion of wiring 30 in third winding portion 31. From another perspective, in the portion where wiring 20 is wound in a spiral shape, wiring 20 is disposed opposite wiring 30, not wiring 20, with base film 10 interposed therebetween. Note that this overlapping relationship between wiring 20 and wiring 30 only needs to be established in at least the portions where wiring 20 and wiring 30 extend linearly in plan view.

[0025] The width of the portion of the wiring 20 in the first winding portion 21 is defined as width W1. The width of the portion of the wiring 20 in the second winding portion 22 is defined as width W2. The width of the portion of the wiring 30 in the third winding portion 31 is defined as width W3. The width of the portion of the wiring 30 in the fourth winding portion 32 is defined as width W4. Widths W1 and W3 are measured in a direction from the inside to the outside of the first winding portion 21. Widths W2 and W4 are measured in a direction from the inside to the outside of the second winding portion 22. Widths W1 to W4 are measured at any 10 measurement points, and the average of the measured values ​​at each of the 10 points is calculated.

[0026] The distance between adjacent portions of wiring 20 in the first winding portion 21 and wiring 30 in the third winding portion 31 is defined as distance SP1. The distance between adjacent portions of wiring 20 in the second winding portion 22 and wiring 30 in the fourth winding portion 32 is defined as distance SP2. Distance SP1 is measured in a direction from the inside to the outside of the first winding portion 21, and distance SP2 is measured in a direction from the inside to the outside of the second winding portion 22. Distances SP1 and SP2 are measured at any 10 measurement points and calculated as the average of the measurements at each of the 10 points.

[0027] The height of wiring 20 is defined as height H1. The height of wiring 30 is defined as height H2. Height H1 is the distance between the main surface of base film 10 and the top surface of wiring 20, and height H2 is the distance between the main surface of base film 10 and the top surface of wiring 30. Heights H1 and H2 are measured at any 10 measurement points and calculated as the average of the measured values ​​at each of the 10 points.

[0028] The widths W1 to W4 are, for example, 4 μm or more and 20 μm or less. The intervals SP1 and SP2 are, for example, 4 μm or more and 20 μm or less. The heights H1 and H2 are, for example, 4 μm or more and 50 μm or less.

[0029] Each of the wiring 20 and the wiring 30 includes, for example, a seed layer 41, an electroless plated layer 42, and an electrolytic plated layer 43.

[0030] The seed layer 41 is disposed on the main surfaces (main surface 10a, main surface 10b) of the base film 10. The constituent material of the seed layer 41 is, for example, a nickel-chromium alloy. However, the constituent material of the seed layer 41 is not limited to this.

[0031] The electroless plated layer 42 is a layer formed by electroless plating. The electroless plated layer 42 is disposed on the seed layer 41. Although not shown, a first through hole and a second through hole are formed in the base film 10 and the seed layer 41. The first through hole overlaps the first land 24 and the second land 25 in a plan view. The second through hole overlaps the third land 34 and the fourth land 35 in a plan view. The electroless plated layer 42 is also formed on the inner wall surfaces of the first through hole and the second through hole. This electrically connects the first land 24 and the second land 25, and electrically connects the third land 34 and the fourth land 35. The constituent material of the electroless plated layer 42 is, for example, copper or a copper alloy. However, the constituent material of the electroless plated layer 42 is not limited thereto.

[0032] The electrolytic plated layer 43 is a layer formed by electrolytic plating. The electrolytic plated layer 43 is disposed on the electroless plated layer 42. The constituent material of the electrolytic plated layer 43 is, for example, copper or a copper alloy. However, the constituent material of the electrolytic plated layer 43 is not limited to this.

[0033] (Manufacturing method of coil device 100) A method for manufacturing the coil device 100 will be described below.

[0034] Fig. 4 is a manufacturing process diagram of the coil device 100. As shown in Fig. 4, the manufacturing method of the coil device 100 includes a preparation step S1, a hole drilling step S2, an electroless plating step S3, a resist pattern forming step S4, an electrolytic plating step S5, a resist pattern removing step S6, and an etching step S7.

[0035] Fig. 5 is an explanatory diagram of the preparation step S1. As shown in Fig. 5, in the preparation step S1, a base film 10 is prepared. A seed layer 41 is formed in advance on the main surface 10a and the main surface 10b of the base film 10 prepared in the preparation step S1. After the preparation step S1, a hole-making step S2 is performed.

[0036] In the drilling process S2, first through holes and second through holes are formed in the base film 10 and the seed layer 41. The first through holes and second through holes are formed by, for example, laser processing or drilling. After the drilling process S2, an electroless plating process S3 is performed.

[0037] 6 is an explanatory diagram of the electroless plating step S3. As shown in FIG. 6, in the electroless plating step S3, an electroless plated layer 42 is formed on a seed layer 41 by electroless plating. Although not shown, the electroless plated layer 42 is also formed on the inner wall surfaces of the first through hole and the second through hole at this time. After the electroless plating step S3, a resist pattern forming step S4 is performed.

[0038] 7 is an explanatory diagram of the resist pattern forming step S4. As shown in FIG. 7, in the resist pattern forming step S4, a resist pattern 50 is formed on the electroless plated layer 42. The resist pattern 50 has openings 51. The electroless plated layer 42 is exposed through the openings 51. The resist pattern 50 is formed, for example, by applying a dry film resist to the electroless plated layer 42 and then exposing and developing the applied dry film resist. After the resist pattern forming step S4, the electrolytic plating step S5 is performed.

[0039] Fig. 8 is an explanatory diagram of the electrolytic plating step S5. As shown in Fig. 8, in the electrolytic plating step S5, an electrolytic plating layer 43 is formed by electrolytic plating on the portion of the electroless plated layer 42 exposed from the opening 51. After the electrolytic plating step S5, a resist pattern removal step S6 is performed.

[0040] 9 is an explanatory diagram of the resist pattern removal step S6. As shown in Fig. 9, in the resist pattern removal step S6, the resist pattern 50 is removed from the electroless plating layer 42. After the resist pattern removal step S6, an etching step S7 is performed.

[0041] In the etching step S7, the portions of the electroless plating layer 42 and the seed layer 41 that were under the resist pattern 50 before removal are removed by etching. In this way, in the manufacturing method of the coil device 100, the wiring 20 and the wiring 30 are formed by a semi-additive method. Note that the method for forming the wiring 20 and the wiring 30 is not limited to this, and they may be formed by, for example, a subtractive method. In this way, the structure of the coil device 100 shown in Figures 1 to 3 is formed.

[0042] (Effects of the coil device 100) The effects of the coil device 100 will be described below in comparison with coil devices according to comparative examples. The coil device 100 according to comparative example 1 is referred to as coil device 200. The coil device according to comparative example 2 is referred to as coil device 300.

[0043] FIG. 10 is a first plan view of the coil device 200. FIG. 11 is a second plan view of the coil device 200 as viewed from the opposite side to that of FIG. 10. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 10. As shown in FIGS. 10, 11, and 12, the coil device 200 has a base film 10, wiring 20, and wiring 30. In this respect, the configuration of the coil device 200 is common to the configuration of the coil device 100.

[0044] In the coil device 200, the wiring 20 has a fifth winding portion 27, a fifth external connection terminal 28, and a sixth external connection terminal 29. The fifth winding portion 27, the fifth external connection terminal 28, and the sixth external connection terminal 29 are arranged on the main surface 10a. In the fifth winding portion 27, the wiring 20 is wound in a spiral shape in a plan view. The fifth external connection terminal 28 and the sixth external connection terminal 29 are connected to the outermost and innermost circumferences of the fifth winding portion 27, respectively. The number of turns of the wiring 20 in the fifth winding portion 27 is greater than the number of turns of the wiring 20 in the first winding portion 21.

[0045] In the coil device 200, the wiring 30 has a sixth winding portion 37, a seventh external connection terminal 38, and an eighth external connection terminal 39. The sixth winding portion 37, the seventh external connection terminal 38, and the eighth external connection terminal 39 are arranged on the main surface 10b. In the sixth winding portion 37, the wiring 30 is wound in a spiral shape in a plan view. The seventh external connection terminal 38 and the eighth external connection terminal 39 are connected to the outermost and innermost circumferences of the sixth winding portion 37. The number of turns of the wiring 30 in the sixth winding portion 37 is greater than the number of turns of the wiring 30 in the third winding portion 31.

[0046] In coil device 200, the portion of wiring 20 in fifth winding portion 27 overlaps with the portion of wiring 30 in sixth winding portion 37 in plan view. From another perspective, in coil device 200, the portion of wiring 20 in fifth winding portion 27 faces the portion of wiring 30 in sixth winding portion 37 with base film 10 interposed therebetween. In these respects, the configuration of coil device 200 differs from the configuration of coil device 100.

[0047] In the coil device 200, the number of turns of the wiring 20 and the number of turns of the wiring 30 can be realized equivalent to that of the coil device 100 with the same number of layers as the coil device 100. However, in the coil device 200, it is unavoidable that one of the external connection terminals on the main surface 10a (the sixth external connection terminal 29) and one of the external connection terminals on the main surface 10b (the eighth external connection terminal 39) are disposed inside the winding portion.

[0048] Therefore, in the coil device 200, an adhesive layer is placed on the main surface 10a (main surface 10b) so as to cover the wiring 20 (wiring 30), and a base film different from the base film 10 is placed on the adhesive layer, and an external connection terminal electrically connected to the sixth external connection terminal 29 (eighth external connection terminal 39) is placed on the base film. As a result, the height of the coil device 200 becomes large.

[0049] On the other hand, in the coil device 100, the first external connection terminal 23, the second external connection terminal 26, the third external connection terminal 33, and the fourth external connection terminal 36 can be arranged outside the winding portion, so that, unlike the coil device 200, the coil device 100 can be made low-profile.

[0050] FIG. 13 is a first plan view of the coil device 300. FIG. 14 is a second plan view of the coil device 300 as viewed from the opposite side to that of FIG. 13. In FIGS. 13 and 14, the wiring 20 is cross-hatched to clearly distinguish between the wiring 20 and the wiring 30. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 13. As shown in FIGS. 13, 14, and 15, the coil device 300 has a base film 10, wiring 20, and wiring 30. In this respect, the configuration of the coil device 200 is common to the configuration of the coil device 100.

[0051] In the coil device 300, a portion of the wiring 20 in the first winding portion 21 overlaps a portion of the wiring 20 in the second winding portion 22 in a plan view, and a portion of the wiring 30 in the third winding portion 31 overlaps a portion of the wiring 30 in the fourth winding portion 32 in a plan view. In this respect, the configuration of the coil device 300 differs from the configuration of the coil device 100.

[0052] Fig. 16 is a graph showing the relationship between differential mode transmission loss and frequency in the coil device 100 and the coil device 300. Fig. 17 is a graph showing the relationship between common mode transmission loss and frequency in the coil device 100 and the coil device 300. Note that the differential mode transmission loss is the transmission loss when AC signals of opposite phases flow through the wiring 20 and the wiring 30, and the common mode transmission loss is the transmission loss when AC signals of the same phase flow through the wiring 20 and the wiring 30.

[0053] 16 and 17, the differential mode transmission loss in coil device 100 was smaller than the differential mode transmission loss in coil device 300. Furthermore, the common mode transmission loss in coil device 100 and the common mode transmission loss in coil device 300 both increased sharply at a specific frequency, but the common mode transmission loss in coil device 100 changed more sharply. From these comparisons, it can be seen that the impedance characteristics are improved according to coil device 100, namely, because the portion of wiring 20 in first winding portion 21 overlaps the portion of wiring 30 in fourth winding portion 32 in plan view, and the portion of wiring 20 in second winding portion 22 overlaps the portion of wiring 30 in third winding portion 31 in plan view.

[0054] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above embodiments, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 10 Base film 10a,10b main surface 20 Wiring 21 Volume 1 22 Volume 2 23 First external connection terminal 24 Land 1 25 Land 2 26 Second external connection terminal 27 Volume 5 28 5th external connection terminal 29 6th external connection terminal 30 Wiring 31 Volume 3 32 Volume 4 33 Third external connection terminal 34 Third Land 35 4th Land 36 4th external connection terminal 37 Volume 6 38 7th external connection terminal 39 8th external connection terminal 41 Seed Layer 42 Electroless plating layer 43 Electroplated layer 50 Resist Pattern 51 Aperture 100, 200, 300 coil device H1, H2 height S1 Preparation process S2 Drilling process S3 Electroless plating process S4 Resist pattern formation process S5 Electrolytic plating process S6 Resist pattern removal process S7 Etching process SP1,SP2 interval W1, W2, W3, W4 width

Claims

1. A base film; A first wiring; a second wiring; the base film has a first major surface and a second major surface; the first wiring has a first winding portion that is disposed on the first main surface and that is spirally wound in a plan view, and a second winding portion that is disposed on the second main surface and that is spirally wound in a plan view, the second wiring has a third winding portion that is disposed on the first main surface and that is spirally wound in a plan view, and a fourth winding portion that is disposed on the second main surface and that is spirally wound in a plan view, a portion of the first wiring in the first winding portion is arranged alternately with a portion of the second wiring in the third winding portion in a direction from the inner periphery toward the outer periphery of the first winding portion, and overlaps with a portion of the second wiring in the fourth winding portion in a plan view, a coil device in which the portion of the first wiring in the second winding portion is arranged alternately with the portion of the second wiring in the fourth winding portion in a direction from the inner circumference toward the outer circumference of the second winding portion, and overlaps with the portion of the second wiring in the third winding portion in a planar view.

2. the first wiring has a first external connection terminal and a first land arranged on the first main surface, and a second external connection terminal and a second land arranged on the second main surface; the first external connection terminal and the first land are connected to the outermost and innermost peripheries of the first winding portion, respectively; the second external connection terminal and the second land are connected to the outermost and innermost peripheries of the second winding portion, respectively; the first land and the second land overlap each other in a plan view, the second wiring has a third external connection terminal and a third land disposed on the first main surface, and a fourth external connection terminal and a fourth land disposed on the second main surface, the third external connection terminal and the third land are connected to the outermost and innermost peripheries of the third winding portion, respectively; the fourth external connection terminal and the fourth land are connected to the outermost and innermost peripheries of the fourth winding portion, respectively; The coil device according to claim 1 , wherein the third land and the fourth land overlap each other in a plan view.

3. a distance between a portion of the first wiring in the first winding portion and a portion of the second wiring in the third winding portion that are adjacent to each other is 20 μm or less; The coil device according to claim 1 , wherein the distance between the portion of the first wiring in the second winding portion and the portion of the second wiring in the fourth winding portion that are adjacent to each other is 20 μm or less.

4. a width of a portion of the first wiring in the first winding portion and a width of a portion of the first wiring in the second winding portion are 20 μm or less; The coil device according to claim 1 , wherein a width of the portion of the second wiring in the third winding portion and a width of the portion of the second wiring in the fourth winding portion are 20 μm or less.

Images