Coil device

Abstract

This coil device comprises a first film, first wiring, a first adhesive layer, a second film, and second wiring. The first film has a first main surface. The first wiring has a first coil part disposed on the first main surface and wound in a spiral shape in plan view, and a first land connected to an end part of the first coil part. The first adhesive layer is disposed on the first main surface so as to cover the first wiring. The second film has a second main surface and a third main surface that is the reverse surface with respect to the second main surface, and is disposed on the first adhesive layer so that the second main surface faces the first adhesive layer. The second wiring has a second coil part disposed on the third main surface and wound in a spiral shape in plan view, and a second land connected to an end part of the second coil part. The second land overlaps the first land in plan view and is electrically connected to the first land.

Description

Coil Device

[0001] The present disclosure relates to a coil device. This application claims priority to Japanese Patent Application No. 2024-102109, filed on June 25, 2024. The entire contents of the Japanese Patent Application are incorporated herein by reference.

[0002] Japanese Patent Laid-Open Publication No. 2021-174794 (Patent Document 1) describes a printed wiring board. The printed wiring board described in Patent Document 1 has a base film, a first wiring, and a second wiring. Each of the first wiring and the second wiring has a coil portion that is wound in a spiral shape in a plan view. The first wiring and the second wiring are arranged on a first main surface and a second main surface of the base film, respectively.

[0003] Japanese Patent Application Laid-Open No. 2021-174794

[0004] A coil device according to the present disclosure includes a first film, a first wiring, a first adhesive layer, a second film, and a second wiring. The first film has a first main surface. The first wiring is disposed on the first main surface and has a first coil portion that is spirally wound in a plan view and a first land connected to an end of the first coil portion. The first adhesive layer is disposed on the first main surface so as to cover the first wiring. The second film has a second main surface and a third main surface opposite the second main surface, and is disposed on the first adhesive layer so that the second main surface faces the first adhesive layer. The second wiring is disposed on the third main surface and has a second coil portion that is spirally wound in a plan view and a second land connected to an end of the second coil portion. The second land overlaps the first land in a plan view and is electrically connected to the first land. The thickness of the second land is greater than the average thickness of the second coil portion.

[0005] FIG. 1 is a first plan view of the coil device 100. FIG. 2 is a second plan view of the coil device 100. FIG. 3 is a third plan view of the coil device 100. FIG. 4 is a fourth plan view of the coil device 100. FIG. 5 is a fifth plan view of the coil device 100. FIG. 6 is a cross-sectional view of the coil device 100. FIG. 7 is a manufacturing process diagram of the coil device 100. FIG. 8 is a cross-sectional view illustrating the electroless plating step S2. FIG. 9 is a cross-sectional view illustrating the resist pattern forming step S3. FIG. 10 is a cross-sectional view illustrating the electrolytic plating step S4. FIG. 11 is a cross-sectional view illustrating the resist pattern removing step S5. FIG. 12 is a cross-sectional view illustrating the etching step S6. FIG. 13 is a cross-sectional view illustrating the electrolytic plating step S7. FIG. 14 is a cross-sectional view illustrating the film attaching step S8. FIG. 15 is a cross-sectional view illustrating the wiring forming step S9. FIG. 16 is a cross-sectional view illustrating the film attaching step S10.

[0006] [Problem to be Solved by the Present Disclosure] In order to improve the function of the printed wiring board as a coil device, it is conceivable to increase the number of stacked coil portions in the printed wiring board described in Patent Document 1. More specifically, it is conceivable to arrange an adhesive layer so as to cover the first wiring, arrange another base film on the adhesive layer, and arrange another wiring (third wiring) having a coil portion on the another base film.

[0007] However, in this case, there is room for improvement in the heat dissipation performance of the heat transferred to the third wiring. The present disclosure provides a coil device with improved heat dissipation performance.

[0008] [Effects of the Present Disclosure] According to the coil device according to the present disclosure, heat dissipation is improved.

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

[0010] (1) A coil device includes a first film, a first wiring, a first adhesive layer, a second film, and a second wiring. The first film has a first main surface. The first wiring is disposed on the first main surface and has a first coil portion that is spirally wound in a plan view and a first land connected to an end of the first coil portion. The first adhesive layer is disposed on the first main surface so as to cover the first wiring. The second film has a second main surface and a third main surface opposite the second main surface, and is disposed on the first adhesive layer so that the second main surface faces the first adhesive layer. The second wiring is disposed on the third main surface and has a second coil portion that is spirally wound in a plan view and a second land connected to an end of the second coil portion. The second land overlaps the first land in a plan view and is electrically connected to the first land. The thickness of the second land is greater than the average thickness of the second coil portion. The coil device described in (1) above improves heat dissipation.

[0011] (2) In the coil device of (1) above, the thickness of the second land may be 1.05 times or more the average thickness of the second coil portion.

[0012] (3) In the coil device of (1) or (2), the value obtained by subtracting the average thickness of the second coil portion from the thickness of the second land may be 2.0 μm or more.

[0013] (4) In the coil device according to (1) to (3) above, the width of the second wiring in the second coil portion may be 45 μm or less.

[0014] (5) In the coil device according to (1) to (4), the outer diameter of the second land may be 75 μm or more.

[0015] (6) The coil device according to (1) to (5) above may further include an insulating layer. The insulating layer may be disposed on the third main surface so as to cover the second wiring. The thickness of the insulating layer on the second land may be smaller than the thickness of the insulating layer on the second coil portion. The coil device according to (6) above further improves heat dissipation.

[0016] (7) In the coil device of (6) above, the thickness of the insulating layer on the second land may be 0.8 times or less the thickness of the insulating layer on the second coil portion.

[0017] (8) In the coil device of (6) or (7) above, the value obtained by subtracting the thickness of the insulating layer on the second land from the thickness of the insulating layer on the second coil portion may be 1.0 μm or more.

[0018] (9) In the coil device according to any one of (6) to (8), the insulating layer may include a second adhesive layer and a third film. The second adhesive layer may be disposed on the third main surface so as to cover the second wiring. The third film may be disposed on the second adhesive layer.

[0019] (10) The coil device according to (1) to (9) may further include a third wiring, a third adhesive layer, a fourth film, the fourth wiring, a fourth adhesive layer, a fifth film, and a fifth wiring. The first film may have a fourth main surface opposite the first main surface. The first wiring may have a third land connected to an end of the first coil portion opposite the first land. The third wiring may be disposed on the fourth main surface and include a third coil portion wound spirally in a plan view, and a fourth land and a fifth land connected to both ends of the third coil portion, respectively. The fourth land may overlap the third land in a plan view and be electrically connected to the third land. The third adhesive layer may be disposed on the fourth main surface so as to cover the third wiring. The fourth film may have a fifth main surface and a sixth main surface opposite the fifth main surface, and may be disposed on the third adhesive layer so that the fifth main surface faces the third adhesive layer. The fourth wiring may be disposed on the sixth main surface and may have a fourth coil portion wound in a spiral shape in a plan view, and a sixth land and a seventh land connected to both ends of the fourth coil portion, respectively. The sixth land may overlap the fifth land in a plan view and be electrically connected to the fifth land. The fourth adhesive layer may be disposed on the sixth main surface so as to cover the fourth wiring. The fifth film may have a seventh main surface and an eighth main surface opposite the seventh main surface, and may be disposed on the fourth adhesive layer so that the seventh main surface faces the fourth adhesive layer. The fifth wiring may be disposed on the eighth main surface and may have an eighth land and an external connection terminal. The eighth land may overlap the seventh land in a plan view and be electrically connected to the seventh land. The external connection terminal may overlap the fourth coil portion in a plan view. According to the coil device of (10) above, heat dissipation is further improved.

[0020] [Details of the embodiment of the present disclosure] Next, details of the 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 a coil device 100.

[0021] (Configuration of Coil Device 100) The configuration of the coil device 100 will be described below.

[0022] FIG. 1 is a first plan view of the coil device 100. In FIG. 1, the insulating layer 40 is omitted. FIG. 2 is a second plan view of the coil device 100. In FIG. 2, a plan view of the coil device 100 seen from the opposite direction to FIG. 1 is shown. In FIG. 2, the wiring 33 is indicated by a dotted line. FIG. 3 is a third plan view of the coil device 100. In FIG. 3, the insulating layer 40, the wiring 23, the film 22, and the adhesive layer 21 are omitted. FIG. 4 is a fourth plan view of the coil device 100. In FIG. 4, a plan view of the coil device 100 seen from the same direction as FIG. 2 is shown, and the wiring 53, the film 52, and the adhesive layer 51 are omitted. FIG. 5 is a fifth plan view of the coil device 100. In FIG. 5, a plan view of the coil device 100 seen from the same direction as FIG. 2 is shown, and the wiring 53, the film 52, the adhesive layer 51, the wiring 33, the film 32, and the adhesive layer 31 are omitted. FIG. 6 is a cross-sectional view of the coil device 100.

[0023] As shown in Figures 1 to 6, the coil device 100 has a film 10, wiring 11, wiring 12, an adhesive layer 21, a film 22, wiring 23, an adhesive layer 31, a film 32, wiring 33, an insulating layer 40, an adhesive layer 51, a film 52, and wiring 53.

[0024] The 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 film 10 is made of a flexible, electrically insulating material. The film 10 is made of, for example, polyimide.

[0025] The wiring 11 is disposed on the main surface 10a. In a plan view, the wiring 11 has a coil portion 11a and lands 11b and 11c. Note that a plan view refers to a case where the coil device 100 is viewed along the normal direction of the main surface 10a (main surface 10b). The coil portion 11a is formed by winding the wiring 11 in a spiral shape in a plan view. The lands 11b and 11c are connected to both ends of the coil portion 11a, respectively. More specifically, the lands 11b and 11c are connected to the outermost and innermost peripheries of the coil portion 11a, respectively.

[0026] The wiring 12 is disposed on the main surface 10b. In plan view, the wiring 12 has a coil portion 12a and lands 12b and 12c. The coil portion 12a is formed by winding the wiring 12 in a spiral shape in plan view. The lands 12b and 12c are connected to both ends of the coil portion 12a. More specifically, the lands 12b and 12c are connected to the outermost and innermost peripheries of the coil portion 12a, respectively. The land 12b overlaps the land 11b in plan view.

[0027] The adhesive layer 21 is disposed on the main surface 10a so as to cover the wiring 11. The adhesive layer 21 is formed of an adhesive. The film 22 has a main surface 22a and a main surface 22b. The main surface 22b is the surface opposite to the main surface 22a. The film 22 is disposed on the adhesive layer 21 so that the main surface 22a faces the adhesive layer 21. The film 22 is formed of a flexible, electrically insulating material.

[0028] The wiring 23 is disposed on the main surface 22b. In plan view, the wiring 23 has a coil portion 23a and lands 23b and 23c. The coil portion 23a is formed by winding the wiring 23 in a spiral shape in plan view. The lands 23b and 23c are connected to both ends of the coil portion 23a, respectively. More specifically, the lands 23b and 23c are connected to the outermost and innermost peripheries of the coil portion 23a, respectively. The land 23c overlaps the land 11c in plan view.

[0029] The thickness of the land 23c is defined as thickness T1. The thickness of the coil portion 23a is defined as thickness T2. The average value of thickness T2 is obtained by measuring thickness T2 at any three measurement points and dividing the sum of the measured values ​​by the number of measurement points. Thickness T1 is greater than the average value of thickness T2. Thickness T1 is, for example, 1.05 times or more the average value of thickness T2. The value obtained by subtracting the average value of thickness T2 from thickness T1 is, for example, 2.0 μm or more.

[0030] The width of the wiring 23 at the coil portion 23a is defined as width W. The outer diameter of the land 23c is defined as outer diameter D. The outer diameter D is larger than the width W. The width W is, for example, 45 μm or less. The outer diameter D is, for example, 75 μm or more.

[0031] The adhesive layer 31 is disposed on the main surface 10b so as to cover the wiring 12. The adhesive layer 31 is formed of an adhesive. The film 32 has a main surface 32a and a main surface 32b. The main surface 32b is the surface opposite to the main surface 32a. The film 32 is disposed on the adhesive layer 31 so that the main surface 32a faces the adhesive layer 31. The film 32 is formed of a flexible, electrically insulating material.

[0032] The wiring 33 is disposed on the main surface 32b. In plan view, the wiring 33 has a coil portion 33a and lands 33b and 33c. The coil portion 33a is formed by winding the wiring 33 in a spiral shape in plan view. The lands 33b and 33c are connected to both ends of the coil portion 33a. More specifically, the lands 33b and 33c are connected to the outermost and innermost peripheries of the coil portion 33a, respectively. The land 33c overlaps the land 12c in plan view.

[0033] The insulating layer 40 is disposed on the main surface 22b so as to cover the wiring 23. The insulating layer 40 has, for example, an adhesive layer 41 and a film 42. The adhesive layer 41 is formed of an adhesive. The adhesive layer 41 is disposed on the main surface 22b so as to cover the wiring 23. The film 42 is disposed on the adhesive layer 41. The film 42 is formed of a flexible, electrically insulating material. The film 42 is formed of, for example, polyimide.

[0034] The thickness of the insulating layer 40 on the land 23c is defined as thickness T3, and the thickness of the insulating layer 40 on the coil portion 23a is defined as thickness T4. The average value of thickness T4 is obtained by measuring thickness T4 at any three measurement points and dividing the sum of the measured values ​​by the number of measurement points. Thickness T3 is smaller than the average value of thickness T4. Thickness T3 is, for example, 0.8 times or less the average value of thickness T4. The value obtained by subtracting thickness T3 from the average value of thickness T4 is, for example, 1.0 μm or more.

[0035] The adhesive layer 51 is disposed on the main surface 32b so as to cover the wiring 33. The adhesive layer 51 is formed of an adhesive. The film 52 has a main surface 52a and a main surface 52b. The main surface 52b is the surface opposite to the main surface 52a. The film 52 is disposed on the adhesive layer 51 so that the main surface 52a faces the adhesive layer 51. The film 52 is formed of a flexible, electrically insulating material.

[0036] The wiring 53 is disposed on the main surface 52b. In plan view, the wiring 53 has a land 53a and an external connection terminal 53b. In plan view, the land 53a overlaps the land 33b. In plan view, the external connection terminal 53b also overlaps the coil portion 33a.

[0037] The wiring 11 and the wiring 12 have an underlayer 13, an electrolytic plating layer 14, and an electrolytic plating layer 15. The underlayer 13 has, for example, a seed layer 13a and an electroless plating layer 13b. The seed layer 13a of the wiring 11 is disposed on the main surface 10a, and the seed layer 13a of the wiring 12 is disposed on the main surface 10b. The electroless plating layer 13b is disposed on the seed layer 13a. A through hole 16 is formed in the film 10 and the seed layer 13a. The through hole 16 overlaps the land 11b and the land 12b in a plan view. The electroless plating layer 13b is also disposed on the inner wall surface of the through hole 16. This electrically connects the land 11b and the land 12b.

[0038] The electrolytic plated layer 14 is disposed on the base layer 13. The electrolytic plated layer 15 is disposed on the side surfaces of the base layer 13, the side surfaces of the electrolytic plated layer 14, and the top surface of the electrolytic plated layer 14. The seed layer 13a is formed of, for example, a nickel-chromium alloy. The electroless plated layer 13b is a layer formed by electroless plating and is formed of, for example, copper or a copper alloy. The electrolytic plated layer 14 and the electrolytic plated layer 15 are layers formed by electrolytic plating and are formed of, for example, copper or a copper alloy.

[0039] The wiring 23 and the wiring 33 each have an underlayer 61, an electrolytic plating layer 62, and an electrolytic plating layer 63. The underlayer 61 has, for example, a seed layer 61a and an electroless plating layer 61b. The seed layer 61a of the wiring 23 is disposed on the main surface 22b, and the seed layer 61a of the wiring 33 is disposed on the main surface 32b. The electroless plating layer 61b is disposed on the seed layer 61a.

[0040] A through hole 64a is formed in the seed layer 61a of the adhesive layer 21, the film 22, and the wiring 23. The through hole 64a overlaps the land 23c and the land 11c in a plan view. A through hole 64b is formed in the seed layer 61a of the adhesive layer 31, the film 32, and the wiring 33. The through hole 64b overlaps the land 33c and the land 12c in a plan view. The electroless plating layer 61b is also disposed on the inner wall surfaces of the through holes 64a and 64b, on the land 11c exposed from the through holes 64a, and on the land 12c exposed from the through holes 64b. This electrically connects the land 11c to the land 23c, and electrically connects the land 12c to the land 33c.

[0041] The electrolytic plated layer 62 is disposed on the base layer 61. The electrolytic plated layer 63 is disposed on the side surfaces of the base layer 61, the side surfaces of the electrolytic plated layer 62, and the top surface of the electrolytic plated layer 62. The seed layer 61a is formed of, for example, a nickel-chromium alloy. The electroless plated layer 61b is a layer formed by electroless plating and is formed of, for example, copper or a copper alloy. The electrolytic plated layer 62 and the electrolytic plated layer 63 are layers formed by electrolytic plating and are formed of, for example, copper or a copper alloy.

[0042] The wiring 53 includes an underlayer 65, an electrolytic plated layer 66, and an electrolytic plated layer 67. The underlayer 65 includes, for example, a seed layer 65a and an electroless plated layer 65b. The seed layer 65a is disposed on the main surface 52b. The electroless plated layer 65b is disposed on the seed layer 65a.

[0043] A through hole 68 is formed in the adhesive layer 51, the film 52, and the seed layer 65a. In a plan view, the through hole 68 overlaps the land 33b and the land 53a. The electroless plating layer 65b is also disposed on the inner wall surface of the through hole 68 and on the land 33b exposed from the through hole 68. This electrically connects the land 33b and the land 53a.

[0044] The electrolytic plated layer 66 is disposed on the base layer 65. The electrolytic plated layer 67 is disposed on the side surfaces of the base layer 65, the side surfaces of the electrolytic plated layer 66, and the top surface of the electrolytic plated layer 66. The seed layer 65a is formed of, for example, a nickel-chromium alloy. The electroless plated layer 65b is a layer formed by electroless plating and is formed of, for example, copper or a copper alloy. The electrolytic plated layer 66 and the electrolytic plated layer 67 are layers formed by electrolytic plating and are formed of, for example, copper or a copper alloy.

[0045] (Method of Manufacturing Coil Device 100) A method of manufacturing the coil device 100 will be described below.

[0046] 7 is a manufacturing process diagram of the coil device 100. As shown in FIG. 7, the manufacturing method of the coil device 100 includes a preparation step S1, an electroless plating step S2, a resist pattern forming step S3, an electrolytic plating step S4, a resist pattern removing step S5, an etching step S6, and an electrolytic plating step S7. The manufacturing method of the coil device 100 further includes a film attaching step S8, a wiring forming step S9, a film attaching step S10, and a wiring forming step S11.

[0047] In the preparation step S1, a film 10 is prepared. In the film 10 prepared in the preparation step S1, seed layers 13a are disposed on the main surfaces 10a and 10b. Furthermore, the film 10 prepared in the preparation step S1 is subjected to a drilling process to form through holes 16. The drilling process is, for example, drilling or laser processing.

[0048] FIG. 8 is a cross-sectional view illustrating the electroless plating step S2. As shown in FIG. 8, in the electroless plating step S2, electroless plating is performed to form an electroless plated layer 13b on the seed layer 13a. At this time, the electroless plated layer 13b is also formed on the inner wall surfaces of the through holes 16. FIG. 9 is a cross-sectional view illustrating the resist pattern forming step S3. As shown in FIG. 9, in the resist pattern forming step S3, a dry film resist is applied to the electroless plated layer 13b, and the dry film resist is exposed and developed to form a resist pattern 70. The resist pattern 70 has openings 70a.

[0049] Fig. 10 is a cross-sectional view illustrating the electrolytic plating step S4. As shown in Fig. 10, in the electrolytic plating step S4, electrolytic plating is performed to form an electrolytic plated layer 14 on the electroless plated layer 13b exposed from the opening 70a. Fig. 11 is a cross-sectional view illustrating the resist pattern removing step S5. As shown in Fig. 11, in the resist pattern removing step S5, the resist pattern 70 is removed.

[0050] FIG. 12 is a cross-sectional view illustrating the etching step S6. As shown in FIG. 12, in the etching step S6, the base layer 13 that was located under the resist pattern 70 is removed by etching. FIG. 13 is a cross-sectional view illustrating the electrolytic plating step S7. As shown in FIG. 13, in the electrolytic plating step S7, electrolytic plating is performed to form an electrolytic plated layer 15 so as to cover the side surfaces of the base layer 13, the side surfaces of the electrolytic plated layer 14, and the top surface of the electrolytic plated layer 14. In this manner, the wiring 11 and the wiring 12 are formed by, for example, a semi-additive method.

[0051] FIG. 14 is a cross-sectional view illustrating the film attachment step S8. As shown in FIG. 14, in the film attachment step S8, the films 22 and 32 are attached. In the film attachment step S8, first, the films 22 and 32 are prepared. At this stage, the uncured adhesive layers 21 and 31 are disposed on the main surfaces 22a and 32a, respectively, and the seed layers 61a are disposed on the main surfaces 22b and 32b. Second, the film 22 is disposed so that the adhesive layer 21 faces the main surface 10a, and the film 32 is disposed so that the adhesive layer 31 faces the main surface 10b. Third, the films 22 and 32 are heated while being pressed toward the main surfaces 10a and 10b, respectively. This results in the attachment of the films 22 and 32. After the films 22 and 32 are attached, a through hole 64a is formed in the seed layer 61a, the film 22, and the adhesive layer 21, and a through hole 64b is formed in the seed layer 61a, the film 32, and the adhesive layer 31.

[0052] FIG. 15 is a cross-sectional view illustrating the wiring formation step S9. As shown in FIG. 15, in the wiring formation step S9, the wiring 23 and the wiring 33 are formed by a semi-additive process. That is, in the wiring formation step S9, the same processes as the electroless plating step S2, the resist pattern formation step S3, the electrolytic plating step S4, the resist pattern removal step S5, the etching step S6, and the electrolytic plating step S7 are performed. As described above, the outer diameter D of the wiring 23 is larger than the width W. Therefore, when electrolytic plating is performed to form the electrolytic plated layer 62 in the wiring formation step S9, the opening of the resist pattern is larger at the position where the land 23c is formed than at the position where the coil portion 23a is formed. As a result, ions for forming the electrolytic plated layer 62 are more easily supplied at the position where the land 23c is formed, and the thickness T1 is larger than the average value of the thickness T2.

[0053] FIG. 16 is a cross-sectional view illustrating the film bonding step S10. As shown in FIG. 16, in the film bonding step S10, the same steps as in the film bonding step S8 are performed to bond the films 42 and 52. After the film 52 is bonded, through holes 68 are formed in the seed layer 65a, the film 52, and the adhesive layer 51. In the wiring formation step S11, wiring 53 is formed by a semi-additive method. That is, in the wiring formation step S11, steps similar to the electroless plating step S2, the resist pattern formation step S3, the electrolytic plating step S4, the resist pattern removal step S5, the etching step S6, and the electrolytic plating step S7 are performed. As a result, the structure of the coil device 100 shown in FIGS. 1 to 6 is formed.

[0054] (Effects of the Coil Device 100) The effects of the coil device 100 will be described below.

[0055] In the coil device 100, the thickness T1 is greater than the average value of the thickness T2, so that heat transferred from the wiring 11 to the land 23c is more easily dissipated from the land 23c. Also, in the coil device 100, the thickness T3 is smaller than the average value of the thickness T4, that is, the thickness of the insulating layer 40 on the land 23c, which prevents heat dissipation, is reduced, so that heat generated in the wiring 11 and transferred to the land 23c is more easily dissipated from the land 23c.

[0056] Furthermore, in the coil device 100, since the external connection terminal 53b overlaps the coil portion 33a, heat transferred from the wiring 33 through the adhesive layer 51 and the film 52 to the external connection terminal 53b is easily dissipated from the external connection terminal 53b.

[0057] 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, not by the above-described embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0058] REFERENCE SIGNS LIST 10 film, 10a, 10b main surface, 11 wiring, 11a coil portion, 11b land, 11c land, 12 wiring, 12a coil portion, 12b, 12c land, 13 underlayer, 13a seed layer, 13b electroless plating layer, 14, 15 electrolytic plating layer, 16 through hole, 21 adhesive layer, 22 film, 22a, 22b main surface, 23 wiring, 23a coil portion, 23b land, 23c land, 31 adhesive layer, 32 film, 32a, 32b main surface, 33 wiring, 33a coil portion, 33b, 33c land, 40 insulating layer, 41 adhesive layer, 42 film, 51 adhesive layer, 52 film, 52a, 52b main surface, 53 wiring, 53a land, 53b External connection terminal, 61 underlayer, 61a seed layer, 61b electroless plating layer, 62, 63 electrolytic plating layer, 64 through hole, 65 underlayer, 65a seed layer, 65b electroless plating layer, 66, 67 electrolytic plating layer, 68 through hole, 70 resist pattern, 70a opening, 100 coil device, D outer diameter, S1 preparation step, S2 electroless plating step, S3 resist pattern forming step, S4 electrolytic plating step, S5 resist pattern removing step, S6 etching step, S7 electrolytic plating step, S8 film bonding step, S9 wiring forming step, S10 film bonding step, S11 wiring forming step, T1, T2, T3, T4 thickness, W width.

Claims

1. A coil device comprising: a first film; a first wiring; a first adhesive layer; a second film; and a second wiring, wherein the first film has a first main surface; the first wiring is disposed on the first main surface and has a first coil portion that is spirally wound in a planar view and a first land connected to an end of the first coil portion; the first adhesive layer is disposed on the first main surface so as to cover the first wiring; the second film has a second main surface and a third main surface that is the opposite side of the second main surface, and is disposed on the first adhesive layer so that the second main surface faces the first adhesive layer; the second wiring is disposed on the third main surface and has a second coil portion that is spirally wound in a planar view and a second land connected to an end of the second coil portion, the second land overlapping the first land in a planar view and being electrically connected to the first land; and the thickness of the second land is greater than the average thickness of the second coil portion.

2. A coil device as described in claim 1, wherein the thickness of the second land is 1.05 times or more the average thickness of the second coil portion.

3. A coil device as described in claim 1 or claim 2, wherein the value obtained by subtracting the average thickness of the second coil portion from the thickness of the second land is 2.0 μm or more.

4. A coil device according to any one of claims 1 to 3, wherein the width of the second wiring in the second coil section is 45 μm or less.

5. A coil device according to any one of claims 1 to 4, wherein the outer diameter of the second land is 75 μm or more.

6. A coil device as described in any one of claims 1 to 5, further comprising an insulating layer, the insulating layer being arranged on the third main surface so as to cover the second wiring, and the thickness of the insulating layer on the second land being smaller than the thickness of the insulating layer on the second coil portion.

7. A coil device according to claim 6, wherein the thickness of the insulating layer on the second land is 0.8 times or less the thickness of the insulating layer on the second coil portion.

8. A coil device according to claim 6, wherein the value obtained by subtracting the thickness of the insulating layer on the second land from the thickness of the insulating layer on the second coil portion is 1.0 μm or more.

9. The coil device according to claim 6, wherein the insulating layer comprises a second adhesive layer and a third film, the second adhesive layer is disposed on the third main surface so as to cover the second wiring, and the third film is disposed on the second adhesive layer.

10. A semiconductor device further comprising a third wiring, a third adhesive layer, a fourth film, a fourth wiring, a fourth adhesive layer, a fifth film, and a fifth wiring, wherein the first film has a fourth main surface opposite to the first main surface, the first wiring has a third land connected to an end of the first coil portion opposite to the first land, the third wiring is disposed on the fourth main surface and has a third coil portion wound in a spiral shape in a plan view, and a fourth land and a fifth land respectively connected to both ends of the third coil portion, the fourth land overlaps the third land in a plan view and is electrically connected to the third land, the third adhesive layer is disposed on the fourth main surface so as to cover the third wiring, the fourth film has a fifth main surface and a sixth main surface opposite to the fifth main surface, and is disposed on the third adhesive layer so that the fifth main surface faces the third adhesive layer, 10. The coil device according to claim 1, wherein the fourth wiring is arranged on the sixth main surface and has a fourth coil portion that is spirally wound in a planar view and a sixth land and a seventh land that are respectively connected to both ends of the fourth coil portion, the sixth land overlapping the fifth land in a planar view and being electrically connected to the fifth land, the fourth adhesive layer being arranged on the sixth main surface so as to cover the fourth wiring, the fifth film having a seventh main surface and an eighth main surface that is the opposite surface to the seventh main surface, and being arranged on the fourth adhesive layer so that the seventh main surface faces the fourth adhesive layer, the fifth wiring is arranged on the eighth main surface and has an eighth land and an external connection terminal, the eighth land overlapping the seventh land in a planar view and being electrically connected to the seventh land, and the external connection terminal overlapping the fourth coil portion in a planar view.

Images