WO2020175477A1

WO2020175477A1 - Printed wiring board

Info

Publication number: WO2020175477A1
Application number: PCT/JP2020/007491
Authority: WO
Inventors: 航野口
Original assignee: 住友電工プリントサーキット株式会社
Priority date: 2019-02-27
Filing date: 2020-02-25
Publication date: 2020-09-03
Also published as: JP7409599B2; CN113366591A; JPWO2020175477A1

Abstract

A printed wiring board of the present disclosure comprises: an insulating base film; an electrically conductive pattern which is laminated on at least one surface side of the base film and has a spiral coil pattern; and one or a plurality of thermal vias which are thermally connected to the coil pattern and disposed through the base film in a region in which the electrically conductive pattern is not laminated.

Description

\¥0 2020/175477 1 卩(: 17 2020/007491 Clarification

Title of invention: Printed wiring board

Technical field

[0001] The present disclosure relates to a printed wiring board.

Background technology

[0002] In recent years, there is an increasing demand for miniaturization of electronic devices. A printed wiring board having a spiral coil pattern is widely used in this electronic device.

As this printed wiring board, for example, a plane coil described in Japanese Patent Laid-Open No. 2000-4_3426456 has been proposed.

Prior art documents

Patent literature

[0004] Patent Document 1: Japanese Unexamined Patent Publication No. 20 0 4 — 3 4 2 6 4 5

Summary of the invention

Problems to be Solved by the Invention

[0005] In the above publication, electroplating is performed on a coil-shaped base conductor layer using a plating solution containing copper sulfate, sulfuric acid, or ethylene glycol as a main component to increase the space factor of the plane coil. , It is stated that a narrow planar coil element between lines can be formed.

[0006] However, when the wiring density of the planar coil is increased in this manner, the conductor resistance of the coil is likely to change due to heat generation of the planar coil when an electric current is applied. Further, the change in the conductor resistance of the wiring may affect the coil characteristics.

[0007] The present disclosure has been made under such circumstances, and an object of the present disclosure is to provide a printed wiring board capable of suppressing a change in conductor resistance of a coil pattern.

Means for solving the problem

[0008] A printed wiring board according to the present disclosure made to solve the above problems includes an insulating base film and at least one surface side of the base film. 〇 2020/175477 2 卩 (: 170? 2020 /007491

A conductive pattern including a spiral coil pattern and one that is thermally connected to the coil pattern and penetrates a region of the base film where the conductive pattern is not laminated. With thermal vias. Effect of the invention

[0009] The printed wiring board according to the present disclosure can suppress changes in the conductor resistance of the coil pattern.

Brief description of the drawings

[0010] [FIG. 1] FIG. 1 is a schematic plan view showing a printed wiring board according to an embodiment of the present disclosure.

[Fig. 2] Fig. 2 is an eight-eight line partial end view of the printed wiring board of Fig. 1.

[FIG. 3] FIG. 3 is a schematic plan view showing a printed wiring board according to an embodiment different from the printed wiring board of FIG.

MODE FOR CARRYING OUT THE INVENTION

[001 1] [Description of Embodiments of the Present Disclosure]

First, embodiments of the present disclosure will be listed and described.

[0012] A printed wiring board according to the present disclosure includes an insulating base film, a conductive pattern that is laminated on at least one surface side of the base film, and includes a spiral coil pattern, the coil pattern, and the thermal pattern. And one or a plurality of thermal vias penetrating the region where the conductive/<<turn is not laminated in the base film.

[0013] Since the printed wiring board is provided with one or more thermal vias that are thermally connected to the coil pattern and penetrate the region of the base film where the conductive patterns are not laminated, when the coil pattern generates heat. However, the heat can be released to the opposite surface side of the base film by the above-mentioned one or more thermal vias. As a result, the printed wiring board can suppress changes in the conductor resistance of the coil pattern.

[0014] The one or more thermal vias may be formed on the inner side of the innermost circumference of the coil pattern. In this way, the above-mentioned one or more thermal vias are 〇 2020/175477 3 卩(: 170? 2020/007491

By forming the coil pattern on the inner side of the innermost circumference, it is possible to suppress the change in the conductor resistance of the coil pattern while increasing the wiring density of the coil pattern.

[0015] It is preferable that the coil pattern has ^_ pairs of linear portions facing each other, and the plurality of thermal vias are arranged along the pair of linear portions. Thus, the coil pattern has a linear portion of the ^_ pairs opposite, by a plurality of the thermal vias are arranged along the pair of linear portions, the wiring density of the coil pattern It is possible to easily and surely suppress the change in the conductor resistance of the coil pattern while increasing the value.

A plurality of dummy wirings adjacent to the outside of the coil pattern may be provided, and at least one dummy wiring may be divided. In this way, by providing a plurality of dummy wirings adjacent to the outside of the coil pattern, the strength of the printed wiring board can be increased. Further, since at least one dummy wiring is divided, it is possible to suppress the diffusion of heat in the plane direction and to more surely release the heat from the one or more thermal vias.

[0017] In the present disclosure, "thermally connected" refers to a state in which heat transfer between the two is possible with a temperature loss of 10% or less (converted to a temperature in Celsius), and the two are not in physical contact with each other. It may be in a bad state. In other words, that the thermal via is thermally connected to the coil pattern means that when a current is applied to the coil pattern, heat is transferred from this coil pattern to the thermal via with a temperature loss of 10% or less. ..

[Details of Embodiments of the Present Disclosure]

Hereinafter, a printed wiring board according to each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0019] [First embodiment]

The printed wiring board 1 in FIGS. 1 and 2 has an insulating base film 2, a conductive pattern 3 including a spiral coil pattern 3 3 laminated on at least one surface side of the base film 2, and a coil pattern. 3 Thermally connected to 3 〇 2020/175477 4 卩 (: 170? 2020 /007491

And a plurality of thermal vias 4 penetrating a region of the base film 2 where the conductive pattern 3 is not laminated. Although not shown, the printed wiring board 1 may include an insulating layer laminated on the base film 2 and the conductive pattern 3. This insulating layer can be formed using, for example, a solder resist or a coverlay.

Since the printed wiring board 1 is provided with a plurality of thermal vias 4 that are thermally connected to the coil pattern 33 and penetrate the region of the base film 2 where the conductive pattern 3 is not laminated, the coil pattern 33 Even if heat is generated, the heat can be released to the opposite surface side of the base film 2 by the plurality of thermal vias 4. That is, the printed wiring board 1 can radiate the heat generated in the coil pattern 33 from the surface side of the base film 2 opposite to the side where the coil pattern 33 is arranged by the plurality of thermal vias 4. .. Thus, the printed wiring board 1 is to prevent the heat from staying in the region where the coil patterns 3 ₃ are formed, as possible out to suppress the change in conductor resistance of the coil pattern 3 3.

[0021] (Base film)

The base film 2 has a synthetic resin as a main component and has electric insulation. The base film 2 is a base material layer for forming the conductive pattern 3. The base film 2 may have flexibility. When the base film 2 has flexibility, the printed wiring board 1 is configured as a flexible printed wiring board. The “main component” means a component having the largest content ratio in terms of mass, for example, a component having a content of 50 mass% or more.

[0022] Examples of the synthetic resin include polyimide, polyethylene terephthalate, liquid crystal polymer, and fluororesin.

When the printed wiring board 1 is a flexible printed wiring board, the lower limit of the average thickness of the base film 2 is preferably 5, and more preferably 10. On the other hand, the upper limit of the average thickness of the base film 2 is preferably 50, and more preferably 40. The average thickness of base film 2 is below the above. 〇 2020/175477 5 卩(: 170? 2020/007491

If it is less than the limit, the insulation strength of the base film 2 may be insufficient. On the contrary, if the average thickness of the base film 2 exceeds the above upper limit, the printed wiring board 1 may be unnecessarily thick and the flexibility may be insufficient. In the present specification, the “average thickness” means the average value of the thicknesses at arbitrary 10 points.

[0024] (Conductive pattern)

The conductive pattern 3 is a layer made of a conductor having conductivity, and includes a spiral coil pattern 33. The conductive pattern 3 also includes a through hole 313 connected to the end of the coil pattern 33.

[0025] á Coil pattern ñ

The coil pattern 38 is, for example, a laminate of a seed layer laminated on the base film 2 and an electroplating layer laminated on the seed layer. Further, the coil pattern 33 may be configured to have a core body composed of the seed layer and the electroplating layer, and a coating layer laminated on the outer surface of the core body by plating. Examples of the main component of the seed layer include copper, nickel, silver and the like. The seed layer is formed by electroless plating, for example. The seed layer may be a sintered body layer of metal particles obtained by applying ink containing metal particles on the surface of the base film 2 and sintering the metal particles. It may be a laminate of plating layers. The electroplated layer is formed by electroplating. Examples of the main component of the electroplated layer include copper, nickel, silver and the like.

[0026] The coil pattern 33 has a pair of opposing straight line portions 30. A pair of straight lines

The distance between the circles 30, that is, the distance between the inner peripheral edges of the pair of conductors arranged on the innermost periphery of the pair of straight portions 30 can be, for example, 200 or more and 300 or less ..

[0027] — The area between the pair of linear portions 30 is a heat radiation for releasing the heat generated in the coil pattern 33 to the surface opposite to the surface where the coil pattern 38 of the base film 2 is laminated. Configured as Region 8. The heat dissipation area 8 is composed of a pair of straight lines 30. 〇 2020/175477 6 卩 (: 170? 2020 /007491

It is an elongated shape whose longitudinal direction is the extending direction. As will be described later, a plurality of thermal vias 4 are arranged in this heat dissipation area 8.

[0028] Except for the above-described heat dissipation region [], the intervals between the adjacent conductors of the coil pattern 33 are preferably uniform. As the lower limit of the average spacing between the adjacent conductors, 5 is preferable, and 10 is more preferable. On the other hand, the upper limit of the average interval is preferably 50, and more preferably 30. If the average interval is less than the lower limit, it may be difficult to form the coil pattern 33. On the contrary, if the average interval exceeds the upper limit, there is a possibility that a desired wiring density cannot be obtained. Incidentally, the case where the average spacing is small, the conductor resistance of the coils pattern 3 ₃ is likely to change due to heat generation. However, since the printed wiring board 1 can intensively radiate heat by the plurality of thermal vias 4, it is possible to sufficiently suppress the change in conductor resistance even when the average interval is set to the upper limit or less. The "average interval" means the average value of the intervals of arbitrary 10 points.

[0029] The width of the conductors forming the coil pattern 33 is preferably uniform. As the lower limit of the average width of the above conductor, 5 is preferable, and 10 is more preferable. On the other hand, the upper limit of the average width of the conductor is preferably 50, and more preferably 30. If the average width is less than the lower limit, it may be difficult to form the coil pattern 33. On the contrary, when the average width exceeds the upper limit, the plane area of the coil pattern 33 becomes large, which may violate the demand for miniaturization of the printed wiring board 1. The "average width" is the average value of the width of any 10 points.

[0030] As the lower limit of the average thickness of the conductor forming the coil pattern 38, 5 is preferable, and 10 is more preferable. On the other hand, as the upper limit of the average thickness,

90 is preferable, and 70 is more preferable. If the average thickness is less than the above lower limit, the conductor resistance may increase. On the other hand, if the average thickness exceeds the upper limit described above, there is a fear that the demand for thinning the printed wiring board 1 is violated. 〇 2020/175 477 7 卩 (: 170? 2020 /007491

[0031] (Thermal via)

As shown in FIG. 2, a plurality of thermal vias 4 penetrates in the thickness direction of the base film 2. The plurality of thermal vias 4 are formed inside the innermost circumference of the coil pattern 33. Specifically, the plurality of thermal vias 4 are formed in the heat dissipation area 8 described above. In this heat dissipation area 8, the surfaces of the plurality of thermal vias 4, preferably both surfaces, are exposed to the outside (that is, the surfaces of the plurality of thermal vias 4 are not covered with another member such as an insulating layer). .. In the printed wiring board 1, the plurality of thermal vias 4 are formed inside the innermost circumference of the coil pattern 33, so that the wiring density of the coil pattern 33 is increased and the conductor of the coil pattern 33 is increased. The change in resistance can be suppressed.

The plurality of thermal vias 4 are arranged along the pair of straight line portions 30. By arranging the plurality of thermal vias 4 along the pair of straight line portions 30, the thermal connection between the coil pattern 33 and the plurality of thermal vias 4 becomes easy and reliable. Further, according to this configuration, heat is likely to be uniformly transferred from the entire area of the coil pattern 33 to the plurality of thermal vias 4. Therefore, it is possible to easily and reliably suppress the change in the conductor resistance of the coil pattern 33 while increasing the wiring density of the coil pattern 33.

[0033] The plurality of thermal vias 4 form, for example, a through hole penetrating in the thickness direction of the base film 2, and a metal is formed on the inner peripheral surface of the through hole and both surfaces of the base film 2 continuous from the inner peripheral surface. It is formed by plating. Copper is preferable as the metal. In addition, examples of the metal plating include electroless plating. Further, after this electroless plating, electroplating may be further performed.

In this embodiment, each thermal via 4 has a cylindrical shape. Each thermal via 4 has lands on both sides in the axial direction. In the printed wiring board 1, it is preferable that the average diameter of the plurality of thermal vias 4 be relatively small and the number of these thermal vias 4 be relatively large. As a result, the thermal vias 4 having a constant thermal conductivity can be densely arranged in the plane direction, and the coil pattern 3 〇 2020/175 477 8 卩 (: 170? 2020 /007491

It is easy to dissipate heat evenly from all areas of 3.

[0035] As the lower limit of the average diameter of the plurality of thermal vias 4 (the average inner diameter of the above-mentioned through holes), 10 is preferable, and 25 is more preferable. On the other hand, the upper limit of the average diameter is preferably 300, more preferably 100. If the average diameter is less than the lower limit, the metal plating connection may be uncertain. On the other hand, if the average diameter exceeds the upper limit, it becomes difficult to arrange a large number of thermal vias 4 densely, and the heat dissipation to the entire coil pattern 33 may become insufficient. The term "diameter" means the diameter when converted into a true circle of equal area. The “average diameter of the thermal via” means the average value of the diameters at the end openings on both sides of the through hole formed in the base film.

[0036] The plurality of thermal vias 4 are linearly arranged along the longitudinal direction of the heat dissipation area. As a lower limit of the number of the plurality of thermal vias 4 arranged in this heat dissipation region, 3 is preferable, and 4 is more preferable. On the other hand, the upper limit of the number is preferably 8 and more preferably 6. If the number is less than the lower limit, the heat radiation property to the entire coil pattern 33 may be insufficient. On the other hand, if the number exceeds the upper limit, the heat dissipation area [unnecessarily increases, which may violate the demand for miniaturization of the printed wiring board 1.

[0037] As the lower limit of the average interval 0 1 of the adjacent thermal vias 4, 10 is preferable, and 25 is more preferable. On the other hand, as the upper limit of the average interval mouth 1,

300 is preferable, and 100 is more preferable. If the average gap opening 1 is less than the above lower limit, it may be difficult to form a plurality of thermal vias 4 or the strength of the base film 2 may be reduced. On the other hand, if the average gap opening 1 exceeds the upper limit, the heat radiation property to the entire coil pattern 33 may be insufficient, or the heat radiation area may become unnecessarily large, and the printed wiring board 1 may be downsized. May violate the requirements of. The interval between adjacent thermal vias means the minimum distance between adjacent thermal vias.

[0038] [Second Embodiment]

The printed wiring board 11 shown in Fig. 3 has an insulating base film and 〇 2020/175 477 9 卩 (: 170? 2020 /007491

— Conductive pattern 13 laminated on at least one surface side of the base film and thermally connected to the conductive pattern 13 including the spiral coil pattern 1 3 3 and the conductive pattern 1 3 3 in the above base film. And a plurality of thermal vias (4) penetrating the area where the layers (3) are not stacked. Although not shown, the printed wiring board 11 may include an insulating layer laminated on the base film and the conductive pattern 13. This insulating layer can be formed using, for example, a solder resist or a coverlay. The above-mentioned base film of the printed wiring board 11 can have the same structure as the base film 2 of the printed wiring board 1 in FIG. Further, since the thermal via 4 of the printed wiring board 11 is the same as the thermal via 4 of the printed wiring board 1 of FIG. 1, the same reference numerals are given and the description thereof is omitted.

The printed wiring board 11 is provided with a plurality of dummy wirings 15 adjacent to the outside of the coil pattern 1 3 ₃ . Also, at least one dummy wiring 15 is divided. The printed wiring board 11 is provided with a plurality of dummy wirings 15 adjacent to the coil patterns 133, so that the strength of the printed wiring board can be increased. In addition, since at least one dummy wiring 15 is divided, the printed wiring board 11 suppresses the diffusion of heat from the area where the coil patterns 1 3 3 are formed to the outer side in the plane direction, and a plurality of thermal vias are provided. The heat can be more reliably dissipated from the 4.

[0040] (Conductive pattern)

The conductive pattern 13 is a layer made of a conductive conductor and includes a spiral coil pattern 1 33. In addition, the conductive pattern 13 includes a through hole 1 3 13 connected to an end of the coil pattern 1 3 3.

[0041] á Coil pattern ñ

The coil pattern 1 3 3 may be a laminate of a seed layer laminated on the base film and an electroplating layer laminated on the seed layer, like the coil pattern 33 of the printed wiring board 1 in FIG. it can. The coil pattern 133 is composed of a core body composed of the seed layer and the electroplating layer, and 〇 2020/175477 10 卩(: 170? 2020/007491

May have a coating layer laminated on the outer surface by plating.

[0042] The coil pattern 133 has a pair of opposing straight line portions (first straight line portion 130). The distance between the pair of first straight line portions 130 facing each other of the coil pattern 13.8 can be the same as the distance between the pair of straight line portions 30 of the printed wiring board 1 in FIG. The coil pattern 133 has one or a plurality of second straight portions 1 3 on one side or both sides in the extending direction of the pair of first straight portions 130.

[0043] - between the first linear portion 1 3_Rei pair region, on the side where the heat generated in the coil Bataan 1 3 3 Koirupata ^_ down 1 3 8 of the base ^_ scan film are stacked face opposite It is configured as a heat dissipation area 8 to escape to the surface side. The heat dissipation area 8 is an elongated shape whose longitudinal direction is the extending direction of the pair of first straight portions 130. In this heat radiation area, a plurality of thermal vias 4 are arranged in the same manner as the printed wiring board 1 in FIG.

[0044] Except for the heat radiation area [¾, they are preferred spacing between adjacent conductors of the coil pattern 1 3 ₃ is uniform. The average spacing between the adjacent conductors can be the same as that of the printed wiring board 1 in FIG. Further, it is preferable that the width of the conductors forming the coil pattern 1333 is uniform. The average width of the conductor can be the same as that of the printed wiring board 1 in FIG.

[0045] (Dummy wiring)

The plurality of dummy wirings 15 are arranged so as to be electrically insulated from the conductive pattern 13. The plurality of dummy wirings 15 may be a laminate of a seed layer laminated on the base film and an electrical plating layer laminated on the seed layer, like the coil pattern 1 33, for example. The core body may be composed of the seed layer and the electroplating layer, and a coating layer may be laminated on the outer surface of the core body by plating.

The plurality of dummy wirings 15 are arranged adjacent to the coil pattern 133, that is, without interposing other wirings or the like. The printed wiring board 11 may include one or a plurality of dummy wirings 15 that are not adjacent to the coil pattern 1 33 in a part of the plurality of dummy wirings 15. Adjacent to the coil pattern 1 3 3 〇 2020/175 477 1 1 卩(: 170? 2020/007491

Examples of the dummy wirings 15 that do not exist include dummy wirings 15 that are arranged in parallel with the coil patterns 1 3 3 with another dummy wiring 15 interposed therebetween.

At least a part of the dummy wirings 15 among the plurality of dummy wirings 15 is arranged in a direction intersecting with the extending direction of the adjacent coil patterns 1 33. In the present embodiment, the plurality of dummy wirings 15 include a plurality of first dummy wirings 15 3 that intersect the second straight line portions 13. The plurality of first dummy wirings 15 3 are arranged so as to be orthogonal to the second straight line portion 1 3.

[0048] As a lower limit of the average interval 0 2 between the plurality of first dummy wirings 1 5 3 and the coil patterns 1 3 3, 5 is preferable. On the other hand, the upper limit of the average spacing port 2 is preferably 50, and more preferably 30. If the average gap opening 2 is less than the lower limit, the plurality of first dummy wirings 15 3 and the coil patterns 1 3 3 may be short-circuited. On the other hand, when the average gap opening 2 exceeds the upper limit, the effect of improving the strength by the plurality of first dummy wirings 15 3 may be insufficient.

[0049] The plurality of first dummy wirings 15 3 are arranged in parallel. In addition, the plurality of first dummy wirings 153 are divided at a part in the longitudinal direction. As described above, since the plurality of first dummy wirings 1 5 3 are divided in a part in the longitudinal direction, the heat generated in the coil pattern 1 3 3 diffuses to the outside of the formation region of the coil pattern 1 3 3. This can be easily suppressed.

[0050] It is preferable that the dividing positions of the plurality of first dummy wirings 153 are random. In other words, it is preferable that the dividing positions of the plurality of first dummy wirings 153 are not linearly arranged. As described above, since the dividing positions of the plurality of first dummy wirings 1 53 are random, it is possible to suppress the reduction in strength due to the dividing of the plurality of first dummy wirings 1 5 3.

It is preferable that the dividing positions of the plurality of first dummy wirings 1 53 are close to the coil pattern 1 33. Since the dividing position of the multiple first dummy wirings 1 5 3 is close to the coil pattern 1 3 3, it is easy to diffuse the heat generated in the coil pattern 1 3 3 out of the formation area of the coil pattern 1 3 3. And surely restrain 〇 2020/175 477 12 boxes (: 170? 2020 /007491

You can The average distance between the divided regions of the plurality of first dummy wirings 1 53 and the coil pattern 1 3 3 can be, for example, 100 or more and 150 0 or less.

[0052] plurality of first dummy wiring 1 5 ₃ of the average length of the separated region! -Is preferably larger than the average interval 0 2 between the plurality of first dummy wirings 1 5 3 and the coil pattern 1 3 3. In this printed wiring board 11, the plurality of first dummy wirings 1 5 3 and the coil patterns 1 3 3 are arranged separately. However, since the gaps between the plurality of first damascene wirings 15 3 and the coil patterns 1 3 3 are arranged in a straight line, increasing the distance between them makes the effect of improving the strength of the printed wiring board 11 insufficient. .. On the other hand, since the dividing positions of the plurality of first dummy wirings 153 can be formed at random, even if the length of the dividing region is relatively large, the strength improving effect is unlikely to be insufficient. Further, by making the length of the divided region relatively large, it is possible to reliably suppress the diffusion of heat.

[0053] The average length of the divided regions of the plurality of first dummy wirings 1 53! The lower limit of-is preferably 10 and more preferably 30. On the other hand, the above average length! As the upper limit of -, 500 is preferable, and 100 is more preferable. If the above average length !- is less than the above lower limit, it may not be possible to sufficiently suppress the diffusion of heat in this divided region. On the contrary, the above average length! If-exceeds the above upper limit, the above dividing area becomes unnecessarily large, and the strength improving effect of the plurality of first dummy wirings 15 3 on the printed wiring board 1 may be insufficient.

[0054] [Other Embodiments]

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present disclosure is not limited to the configurations of the above-described embodiments, but is indicated by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope. It

[0055] For example, in the above embodiment, the configuration including a plurality of thermal vias has been described, but the printed wiring board may include only one thermal via. Also, one or more thermal vias increase the wiring density of the coil pattern. 〇 2020/175 477 13 卩 (: 170? 2020 /007491

It is preferable that the coil pattern is formed on the inner side of the innermost circumference of the coil pattern from the viewpoint that it can be formed. Or may be formed outside the coil pattern.

The printed wiring board may be provided with a conductive pattern only on one side of the base film, or may be provided with conductive patterns on both sides of the base film. Further, the shape of the coil pattern on the printed wiring board is not limited to the shape of the above-described embodiment, and for example, the pair of linear portions facing each other may not be provided.

When the printed wiring board has a plurality of dummy wirings, the specific layout of these dummy wirings is not limited to the layout described in the above embodiment. Further, the printed wiring board has one or a plurality of dummy wirings arranged in parallel with the extending direction of the coil pattern, and the one or a plurality of dummy wirings may be divided.

Industrial availability

[0058] As described above, the printed wiring board according to the embodiment of the present disclosure can suppress the change in the conductor resistance of the coil pattern, and thus is preferably used for various electronic devices.

Explanation of symbols

[0059] 1, 1 1 Printed wiring board

2 base film

3, 1 3 Conductive pattern

3, 1 3 3 coil pattern

1 3 sack through hole

30 Straight part

4 Thermal via

1 3 ○ 1st straight line part

1 3 2nd straight section \¥0 2020/175 477 14 卩 (: 17 2020 /007491

1 5 Dummy wiring

1 5 8 1st dummy wiring

Heat dissipation area

Claims

\¥0 2020/175 477 15 卩(: 17 2020/007491 Claims

[Claim 1] An insulating base film,

A conductive pattern laminated on at least one surface side of the base film and including a spiral coil pattern;

One or a plurality of thermal vias that are thermally connected to the coil pattern and penetrate the region of the base film where the conductive pattern is not laminated.

A printed wiring board equipped with.

[Claim 2] The printed wiring board according to claim 1, wherein the one or more thermal vias are formed inside the innermost periphery of the coil pattern.

[Claim 3] The coil pattern has a pair of linear portions facing each other,

The printed wiring board according to claim 2, wherein the plurality of thermal vias are arranged along the pair of linear portions.

4. The printed wiring board according to claim 1, claim 2 or claim 3, comprising a plurality of dummy wirings adjacent to the outside of the coil pattern, wherein at least one dummy wiring is divided.