JP2019192806A - Flexible printed wiring board, manufacturing method of the flexible printed wiring board, and electron member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible printed wiring board capable of suppressing radiation noise. A flexible printed wiring board (1) according to the present invention has a laminated wiring board (100) and a conductive shield layer (51) formed on one surface of an insulating insulation coating layer (52), and has an upper surface and a lower surface of the laminated wiring board (100). The shield film 200 covers the shield layer 51 side and covers at least a part of both end surfaces of the laminated wiring board 100 on the shield layer 51 side. The laminated wiring board 100 includes a conductive layer 11, an insulating layer 21 provided on the conductive layer 11, a signal circuit 30 provided on the insulating layer 21, an insulating layer 21 and insulation provided on the signal circuit 30. The layer 22 and the conductive layer 12 provided on the insulating layer 22 are included. The shield layer 51 is connected to the conductive layer 12. [Selection diagram] Figure 1

Description

  The present invention relates to a flexible printed wiring board, a method for manufacturing a flexible printed wiring board, and an electronic member, and more particularly, to a flexible printed wiring board having a shield film that shields electromagnetic waves, a method for manufacturing a flexible printed wiring board, and an electronic member.

  A flexible printed circuit board (Flexible Printed Circuits: FPC) is a printed circuit board in which a signal circuit or the like is formed on a flexible insulating film. For this reason, the flexible printed wiring board can be bent, and as the OA equipment, communication equipment, mobile phone, etc. in recent years become more high-performance and downsized, the inside of the casing having its narrow and complicated structure is electronic. Often used to incorporate circuits. In recent years, with the high-density mounting of electronic components due to downsizing of electronic devices and the high frequency of signals due to the increase in the amount of communication information, countermeasures against unnecessary radiation noise generated from flexible printed wiring boards have become increasingly important. ing.

  The shield film is affixed so as to be sandwiched from the upper surface and the lower surface of the flexible printed wiring board to reduce radiation noise leaking from the flexible printed wiring board.

JP 2000-269632 A Japanese Patent Application Laid-Open No. 2003-234022

  Patent Document 1 discloses a conventional flexible printed wiring board. As shown in FIG. 10, a conventional flexible printed wiring board 1001 is provided with a signal circuit 1003 and a ground circuit 1004 on an insulating layer 1002. Insulating layers 1005 and 1006 are provided so as to cover the signal circuit 1003 and the ground circuit 1004. Further, a laminated structure in which a shield film 1009 including a conductive layer 1007 and an insulating coating layer 1008 is attached to the upper surface of 1006 and the lower surface of the insulating layer 1002 is formed. The conductive layer 1007 in the shield film 1009 is connected to the ground circuit 1004 through the via 1011 in the through hole 1010 formed in the insulating layers 1005 and 1006.

  In the method of attaching the electromagnetic wave shielding film 1009 as shown in FIG. 10, leakage of radiation noise 1012 occurs from the end faces on both sides of the flexible printed wiring board 1001 particularly when a high frequency signal is passed. Since the radiation noise 1012 leaked to the outside adversely affects peripheral devices, the need to shield the signal circuit 1003 in three dimensions is increasing.

  Patent Document 2 discloses a flexible flat cable covered with an electromagnetic wave absorbing material. As shown in FIG. 11, a flexible flat cable 1021 used in a digital camera is covered with a thin sheet-like electromagnetic wave absorber 1022 of an electrical insulator composed of magnetic metal powder and rubber on both upper and lower surfaces. Yes. The electromagnetic wave absorbing material 1022 covers the flexible flat cable 1021 by using an extremely thin thermosetting adhesive 1023 and adhering from above and below. In Patent Document 2, high-frequency electromagnetic noise directly radiated from the flexible flat cable 1021 is absorbed by a sheet-like electromagnetic wave absorber, and the high-frequency electromagnetic noise is caused to cause heat loss. However, the electromagnetic wave absorbing material 1022 may not sufficiently absorb high frequency electromagnetic noise.

  The present invention has been made to solve such problems, and a flexible printed wiring board capable of suppressing radiation noise even when a high-frequency signal is passed, a method for manufacturing a flexible printed wiring board, and an electronic member I will provide a.

  A flexible printed wiring board according to the present invention is a laminated wiring board extending in one direction and a shield film in which a conductive shield layer is formed on one side of an insulating insulating coating layer, the upper surface of the laminated wiring board. And the lower surface is covered with the shield layer side, and at least a part of both end faces in the other direction perpendicular to the one direction in the plane parallel to the upper surface of the laminated wiring board is covered with the shield layer side. The laminated wiring board is provided with a first conductive layer, a first insulating layer provided on the first conductive layer, and provided on the first insulating layer and extending in the one direction. A signal circuit having a portion, a first insulating layer, a second insulating layer provided on the signal circuit, and a second conductive layer provided on the second insulating layer, and the shield layer Is connected to the second conductive layer

  The method for manufacturing a flexible printed wiring board according to the present invention includes a first conductive layer, a first insulating layer provided on the first conductive layer, and provided on the first insulating layer and extending in one direction. A laminated wiring board including a signal circuit having a portion, a first insulating layer, a second insulating layer provided on the signal circuit, and a second conductive layer provided on the second insulating layer is prepared. Covering the lower surface of the laminated wiring board with the shield layer side of the shield film, the step of preparing, a step of preparing a shield film having a conductive shield layer formed on one side of the insulating insulating coating layer, The upper surface of the laminated wiring board is covered with the shield layer side of the shield film, and at least a part of both end faces in the other direction orthogonal to the one direction in a plane parallel to the upper surface of the laminated wiring board Shield film Serial and a step of covering with a shield layer side, and a step of pressing the shield film covering the laminated wiring board and the laminated wiring board in the vertical direction.

  The electronic member according to the present invention is one in which the flexible printed wiring board is connected.

  ADVANTAGE OF THE INVENTION According to this invention, even when a high frequency signal is sent, the flexible printed wiring board which can suppress radiation noise, the manufacturing method of a flexible printed wiring board, and an electronic member can be provided.

1 is a cross-sectional view illustrating a flexible printed wiring board according to a first embodiment. 3 is a flowchart illustrating a method for manufacturing a flexible printed wiring board according to Embodiment 1. FIG. It is sectional drawing which illustrated the flexible printed wiring board which concerns on a comparative example. FIG. 3 is a cross-sectional view illustrating the main part of the flexible printed wiring board according to the first embodiment. 6 is a cross-sectional view illustrating a flexible printed wiring board according to a second embodiment. FIG. 6 is a cross-sectional view illustrating a flexible printed wiring board according to a third embodiment. FIG. 10 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 1 of Embodiment 3. FIG. 10 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 2 of Embodiment 3. FIG. 10 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 3 of Embodiment 3. FIG. It is sectional drawing which illustrated the flexible printed wiring board. It is the perspective view which illustrated the flexible flat cable covered with the electromagnetic wave absorber. FIG. 6 is a cross-sectional view illustrating a flexible printed wiring board according to a modified example of Embodiment 1. It is the figure which illustrated the kind of shield film. It is the figure which illustrated the composition and measurement result of Examples 1-10. It is the graph which illustrated the measurement result of Examples 1-10, a horizontal axis shows an Example and a vertical axis shows a shield effect.

(Embodiment 1)
A flexible printed wiring board according to Embodiment 1 will be described. First, the configuration of the flexible printed wiring board will be described. FIG. 1 is a cross-sectional view illustrating a flexible printed wiring board according to the first embodiment. As shown in FIG. 1, the flexible printed wiring board 1 includes a laminated wiring board 100, a shield film part 201, a shield film part 202, a cover layer 301, and a cover layer 302. The flexible printed wiring board 1 has flexibility because it includes a film-like member, a thin member, a flexible member, and the like. The flexible printed wiring board 1 extends in one direction in a flat state.

  Here, for convenience of explanation of the flexible printed wiring board 1, an XYZ orthogonal coordinate system is introduced. The direction in which the flexible printed wiring board 1 extends in the state in which the flexible printed wiring board 1 is flattened is defined as the X-axis direction. A direction orthogonal to the upper surface of the flexible printed wiring board 1 is defined as a Z-axis direction. Therefore, the thickness direction of the flexible printed wiring board 1 is the Z-axis direction. Both end surfaces of the flexible printed wiring board 1 are oriented in the Y-axis direction.

  The laminated wiring board 100 extends in one direction, that is, in the X-axis direction. The laminated wiring board 100 is, for example, a flexible wiring board. The laminated wiring board 100 includes a conductive layer 11, a conductive layer 12, an insulating layer 21, an insulating layer 22, an insulating layer 23, a signal circuit 30 and a ground circuit 40. The laminated wiring board 100 is laminated in the order of the conductive layer 11, the insulating layer 21, the insulating layer 22, the insulating layer 23, and the conductive layer 12 from below. A signal circuit 30 and a ground circuit 40 are provided between the insulating layer 21 and the insulating layer 22. In the laminated wiring board 100, another conductive layer or insulating layer may be inserted between the layers. In the other direction orthogonal to one direction in the plane parallel to the upper surface 102 of the multilayer wiring board 100, that is, in the Y-axis direction, both end faces face each other.

  The conductive layer 11 is formed over the lower surface 101 of the laminated wiring board 100, for example. The insulating layer 21 is provided on the conductive layer 11. The signal circuit 30 is provided on the insulating layer 21. The signal circuit 30 has a portion extending in the X-axis direction on the insulating layer 21. A plurality of signal circuits 30 may be provided. The signal circuit 30 may include a signal circuit 31 and a signal circuit 32, for example. For example, the signal circuit 31 is disposed on the −Y axis direction side of the signal circuit 32.

  The ground circuit 40 is provided on the insulating layer 21. The ground circuit 40 has a portion extending in the X-axis direction on the insulating layer 21. The ground circuit 40 is provided at a distance from the signal circuit 30. The ground circuit 40 has a portion extending in the X-axis direction along the signal circuit 30. A plurality of ground circuits 40 may be provided. The ground circuit 40 may include a ground circuit 41 and a ground circuit 42, for example. For example, the ground circuit 41 is disposed on the −Y axis direction side of the signal circuit 31. The ground circuit 42 is disposed on the + Y axis direction side of the signal circuit 32. The ground circuit 41 and the ground circuit 42 are provided so as to sandwich the signal circuits 31 and 32 from both sides on the + Y axis direction side and the −Y axis direction side. Therefore, the signal circuit 30 is disposed between the ground circuit 41 and the ground circuit 42.

  The insulating layer 22 is provided on the insulating layer 21, the signal circuit 30, and the ground circuit 40. The insulating layer 22 is provided on the insulating layer 21 so as to cover the signal circuit 30 and the ground circuit 40 from above. The insulating layer 23 is provided on the insulating layer 22. The conductive layer 12 is provided on the insulating layer 23.

  The laminated wiring board 100 may be formed using, for example, a double-sided flexible copper-clad laminate (hereinafter referred to as double-sided FCCL) and a single-sided flexible copper-clad laminate (hereinafter referred to as single-sided FCCL). The double-sided FCCL is formed by forming a copper foil on both sides of a film-like insulating base material layer. Single-sided FCCL is obtained by forming a copper foil on one side of a film-like insulating base material layer.

  The copper foil on one side of the double-sided FCCL is used as the conductive layer 11, and the insulating base material layer is used as the insulating layer 21. The copper foil on the other surface is patterned and used as the signal circuit 30 and the ground circuit 40. Further, the copper foil on one surface of the single-sided FCCL is used as the conductive layer 12, and the insulating base material layer is used as the insulating layer 23. When the double-sided FCCL and single-sided FCCL are used, the laminated wiring board 100 is formed as follows. That is, the signal circuit 30 and the ground circuit 40 are formed by patterning the other surface of the double-sided FCCL. Next, the insulating base layer side of the single-sided FCCL is bonded to the patterned surface of the double-sided FCCL. Thereby, the laminated wiring board 100 is formed. The insulating adhesive used for bonding becomes the insulating layer 22.

  The double-sided and single-sided FCCL insulating substrate layers are preferably polyester, polycarbonate, polyimide, polyphenylene sulfide, and liquid crystal polymer, and more preferably liquid crystal polymer and polyimide. Among these, a liquid crystal polymer having a low relative dielectric constant and dielectric loss tangent is more preferable in consideration of the use of a flexible printed wiring board that transmits a high-frequency signal. By providing such an insulating base material, the flexible printed wiring board 1 has high heat resistance.

  The signal circuit 30 sends an electrical signal to an electronic member connected via the flexible printed wiring board 1. The ground circuit 40 is set to a ground potential for grounding. The material used for the conductive layer 11, the conductive layer 12, the signal circuit 30, and the ground circuit 40 is not limited to copper foil as long as it is conductive. Further, the laminated wiring board 100 is not limited to the one formed using the double-sided FCCL and the single-sided FCCL. For example, the conductive layer 11, the insulating layer 21, the signal circuit 30 and the ground circuit 40, the insulating layer 22, the insulating layer 23, and the conductive layer 12 may be stacked in this order.

  The thicknesses of the conductive layer 11, the conductive layer 12, the signal circuit 30, and the ground circuit 40 are, for example, 18 [μm]. The thickness of the insulating layer 21 and the insulating layer 23 is, for example, 50 [μm]. The thickness of the insulating layer 22 is, for example, 35 [μm]. The thickness of each layer included in the multilayer wiring board 100 is not limited to the above-described thickness as long as the multilayer wiring board 100 is flexible, and may be about 1 to 200 [μm].

  The insulating cover layer 301 is provided below the laminated wiring board 100. The insulating cover layer 302 is provided above the laminated wiring board 100. The cover layers 301 and 302 are insulating materials that cover the laminated wiring board 100 and protect it from the external environment. Since the conductive layers 11 and 12 are exposed over the lower surface 101 and the upper surface 102 of the laminated wiring board 100, the cover layers 301 and 302 cover the conductive layers 11 and 12. The cover layers 301 and 302 include, for example, a cover lay 61 and an insulating adhesive layer 62. The coverlay 61 includes, for example, a resin such as polyimide as a material. The insulating adhesive layer 62 is, for example, an insulating adhesive. Note that the cover layers 301 and 302 are not limited to the structure including the cover lay 61 and the insulating adhesive layer 62, but are a thermosetting or ultraviolet curable solder resist, a photosensitive cover lay film, and a photosensitive property suitable for fine processing. A coverlay film or the like may be used, and a thermosetting adhesive or the like may be used. The thickness of the cover layers 301 and 302 is, for example, 10 to 100 [μm], and preferably, for example, 60 [μm]. The thickness of the coverlay 61 is, for example, 25 [μm], and the thickness of the insulating adhesive layer 62 is, for example, 35 [μm].

  The cover layers 301 and 302 have the insulating adhesive layer 62 side adhered to the laminated wiring board 100. Through holes 63 are formed in the cover layers 301 and 302. The through hole 63 penetrates the cover lay 61 and the insulating adhesive layer 62. An earth via 64 is formed inside the through hole 63. Therefore, the ground via 64 penetrates the cover layers 301 and 302.

  The shield film portions 201 and 202 include an insulating insulating coating layer 52 and a conductive shield layer 51. The shield film portions 201 and 202 are obtained by forming the shield layer 51 on one side of the insulating coating layer 52. The shield film portions 201 and 202 are collectively referred to as a shield film 200. Therefore, the shield film 200 includes a shield film portion 201 that covers the lower surface 101 of the laminated wiring board 100 and a shield film portion 202 that covers the upper surface 102. The shield film 200 shields the laminated wiring board 100.

  For example, the shield layer 51 is obtained by curing the conductive adhesive of the shield film 200. Therefore, the shield film 200 includes the shield layer 51 and the insulating coating layer 52 in the flexible printed wiring board 1, and the conductive adhesive layer and the insulating coating layer in a single unit before becoming a member of the flexible printed wiring board 1. 52. Note that the shield layer 51 of the shield film 200 is not limited to the one in which the conductive adhesive is cured as long as it has conductivity.

  As shown in FIG. 12, the shield film 200 may include a metal layer 53 formed between the insulating coating layer 52 and the shield layer 51. That is, in the flexible printed wiring board 1, the shield film 200 is composed of a shield layer 51 in which a conductive adhesive is cured, an insulating coating layer 52, and a metal layer 53 between the two, and the flexible printed wiring board. As a single unit before becoming one member, a conductive adhesive layer, a metal layer 53 and an insulating coating layer 52 may be laminated. The metal layer 53 is, for example, a copper foil.

  Here, the conductive adhesive layer and the insulating coating layer 52 in the shield film 200 will be described.

<< Conductive adhesive layer >>
The conductive adhesive layer can be appropriately selected from an isotropic conductive adhesive layer or an anisotropic conductive adhesive layer. The isotropic conductive adhesive layer has conductivity in the vertical direction and the horizontal direction with the shield film 200 placed horizontally. The anisotropic conductive adhesive layer has conductivity only in the vertical direction with the shield film 200 placed horizontally. The conductive adhesive layer may be either isotropic conductive or anisotropic conductive, and isotropic conductive is preferable because the connection reliability at the ground via 64 is improved. Further, it is also effective in reducing noise leakage from the end faces 103 and 104 of the flexible printed wiring board 1. The conductive adhesive layer can be formed using a conductive adhesive. As the conductive adhesive, a conventionally known adhesive containing a thermosetting resin, a curing agent, and conductive fine particles can be arbitrarily used. Below, a thermosetting resin, a hardening | curing agent, and electroconductive fine particles are demonstrated.

<Thermosetting resin>
A thermosetting resin is a resin having a plurality of functional groups capable of reacting with a curing agent. Functional groups include, for example, hydroxyl group, phenolic hydroxyl group, methoxymethyl group, carboxyl group, amino group, epoxy group, oxetanyl group, oxazoline group, oxazine group, aziridine group, thiol group, isocyanate group, blocked isocyanate group, blocked A carboxyl group, a silanol group, etc. are mentioned. Thermosetting resins include, for example, acrylic resins, maleic resins, polybutadiene resins, polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, polyamideimide resins, phenolic resins. Known resins such as resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluorine resins can be used.

  Thermosetting resins can be used alone or in combination of two or more. Among these, polyurethane resin, polyurethane urea resin, epoxy resin, phenoxy resin, polyimide resin, polyamide resin, and polyamideimide resin are preferable from the viewpoint of flexibility. 1-50 mgKOH / g is preferable and, as for the acid value of a thermosetting resin, 3-30 mgKOH / g is more preferable. The weight average molecular weight of the thermosetting resin is preferably 20,000 to 100,000. The content of the thermosetting resin in the solid content of the conductive adhesive layer is preferably 5 to 99% by weight, more preferably 7 to 80% by weight, and still more preferably 10 to 60% by weight.

<Curing agent>
The curing agent has a plurality of functional groups that can react with the functional groups of the thermosetting resin. Examples of the curing agent include known compounds such as an epoxy compound, an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound, a phenol compound, and an organometallic compound. A hardening | curing agent can be used individually or in combination with 2 or more types. It is preferable that 1-50 weight part of various hardening | curing agents are included with respect to 100 weight part of thermosetting resins, 3-30 weight part is more preferable, and 3-20 weight part is further more preferable.

<Conductive fine particles>
The conductive fine particles have a function of imparting conductivity to the conductive adhesive layer. The conductive fine particles are preferably, for example, conductive metals such as gold, platinum, silver, copper and nickel, and alloys thereof, and conductive polymer fine particles. From the viewpoint of price and conductivity, silver or copper is preferable. More preferred.

  In addition, composite fine particles having a coating layer in which a metal or a resin is used as a core and the surface of the core is covered, are preferable from the viewpoint of cost reduction. Here, the core is preferably selected appropriately from inexpensive nickel, silica, copper and alloys thereof, and resins. The coating layer is preferably a conductive metal or a conductive polymer. Examples of the conductive metal include gold, platinum, silver, nickel, manganese, indium, and alloys thereof. Examples of the conductive polymer include polyaniline and polyacetylene. Among these, silver or copper is preferable from the viewpoints of price and conductivity.

The shape of the conductive fine particles is not limited as long as desired conductivity is obtained. Specifically, for example, a spherical shape, a flake shape, a leaf shape, a dendritic shape, a plate shape, a needle shape, a rod shape, and a grape shape are preferable. Moreover, you may mix two types of electroconductive fine particles of these different shapes.
The conductive fine particles can be used alone or in combination of two or more.

  The average particle diameter of the conductive fine particles is a D50 average particle diameter, and is preferably 2 μm or more, more preferably 5 μm or more, and further preferably 7 μm or more from the viewpoint of sufficiently ensuring conductivity. On the other hand, from the viewpoint of making the conductive adhesive layer thin, 30 μm or less is preferable, 20 μm or less is more preferable, and 15 μm or less is even more preferable. The D50 average particle diameter can be determined by a laser diffraction / scattering particle size distribution measuring apparatus or the like.

  The content of the conductive fine particles in the solid content of the conductive adhesive layer is preferably 1 to 95% by weight, more preferably 20 to 93% by weight, and still more preferably 40 to 90% by weight. It is preferable to mix | blend 10-700 weight part with respect to 100 weight part, and 20-500 weight part is more preferable. When content is 20-500 weight part, it can be set as the shield film 200 with more favorable electromagnetic wave shielding property.

  Conductive adhesives include silane coupling agents, rust inhibitors, reducing agents, antioxidants, pigments, dyes, tackifying resins, plasticizers, UV absorbers, antifoaming agents, leveling regulators as optional components. Fillers and flame retardants can be blended.

  The conductive adhesive can be obtained by mixing and stirring the materials described so far. For the stirring, for example, a known stirring device can be used for a disperse mat, a homogenizer or the like.

  A known method can be used for producing the conductive adhesive layer. For example, a method of forming a conductive layer by applying a conductive adhesive on a peelable sheet and drying, or extruding the conductive adhesive into a sheet using an extruder such as a T-die It can also be formed.

  Coating methods include, for example, gravure coating method, kiss coating method, die coating method, lip coating method, comma coating method, blade method, roll coating method, knife coating method, spray coating method, bar coating method, spin coating method, dip coating. A known coating method such as a method can be used. In coating, it is preferable to perform a drying step. In the drying step, for example, a known drying device such as a hot air dryer or an infrared heater can be used.

  2-100 micrometers is preferable, as for the thickness of a conductive adhesive layer, 4-50 micrometers is more preferable, and 6-30 micrometers is further more preferable. When the thickness is in the range of 2 to 100 μm, it becomes easy to balance the electromagnetic shielding properties and the flexibility.

<< Insulation coating layer >>
The insulating coating layer can be formed using a conventionally known insulating resin composition. The insulating resin composition can contain an optional component as necessary for the thermosetting resin and the curing agent described in the conductive adhesive. The thermosetting resin and the curing agent used for the insulating layer and the conductive adhesive layer may be the same or different. The insulating resin composition can be obtained by the same method as that for the conductive adhesive. The insulating layer may be a film formed of an insulating resin such as polyester, polycarbonate, polyimide, polyphenylene sulfide or the like. The thickness of the insulating layer is usually about 2 to 20 μm.

  The shield film unit 201 covers the lower surface 101 of the laminated wiring board 100 on the shield layer 51 side. Therefore, the surface on the shield layer 51 side faces the lower surface 101 on the laminated wiring board 100 side. The shield film part 201 covers the laminated wiring board 100 and is in contact with the cover layer 301. Therefore, the cover layer 301 is provided between the lower surface 101 of the laminated wiring board 100 and the shield film portion 201 that covers the lower surface 101. The shield film unit 201 covers the lower surface 101 of the laminated wiring board 100 on the shield layer 51 side, and covers at least a part of both end faces of the laminated wiring board 100 in the Y-axis direction on the shield layer 51 side. For example, the shield film unit 201 covers both end surfaces of the conductive layer 11, the insulating layer 21, and the insulating layer 22 of the laminated wiring board 100. Therefore, the shield film part 201 is in contact with both end faces of the conductive layer 11. The shield film part 201 covers both end surfaces of the cover layer 301.

  The shield film part 202 covers the upper surface 102 of the laminated wiring board 100 on the shield layer 51 side. Therefore, the surface on the shield layer 51 side faces the upper surface 102 on the laminated wiring board 100 side. The shield film part 202 covers the laminated wiring board 100 and is in contact with the cover layer 302. Therefore, the cover layer 302 is provided between the upper surface 102 of the laminated wiring board 100 and the shield film portion 202 that covers the upper surface 102. The shield film portion 202 covers the upper surface 102 of the laminated wiring board 100 on the shield layer 51 side, and covers at least a part of both end faces of the laminated wiring board 100 in the Y-axis direction on the shield layer 51 side. For example, the shield film portion 202 covers both end surfaces of the conductive layer 12, the insulating layer 23, and the insulating layer 22 of the laminated wiring board 100. Therefore, the shield film part 202 is in contact with both end surfaces of the conductive layer 12. Further, the shield film portion 202 covers both end faces of the cover layer 302.

  Both end surfaces of the laminated wiring board 100, that is, the end surfaces 103 and 104 are covered with the shield layer 51 from the conductive layer 11 to the conductive layer 12. Both end surfaces of the laminated wiring board 100 are covered with the shield layers 51 of the shield film portion 201 and the shield film portion 202 over the entire surface.

  The boundary where shield film portions 201 and 202 cover both end faces in the Y-axis direction of laminated wiring board 100 is not limited to both end faces of insulating layer 22. For example, the shield film portion 201 covers both end surfaces of the cover layer 301 and the conductive layer 11, and the shield film portion 202 includes both ends of the cover layer 302, the conductive layer 12, the insulating layer 23, the insulating layer 22, and the insulating layer 21. The boundary on both end faces of the shield film portions 201 and 202 may be anywhere on both end faces, such as covering the face.

  The shield layers 51 of the shield film portions 201 and 202 may cover both end surfaces so as to extend in the X-axis direction along the signal circuit 30. The shield layer 51 may cover the entire surface of both end surfaces along the signal circuit 30. The shield layers 51 of the shield film portions 201 and 202 may have portions extending from both end surfaces of the laminated wiring board 100 in the outer Y-axis direction. The shield layer 51 may include a portion extending in the −Y axis direction from the end surface 103 on the −Y axis direction side and a portion extending in the + Y axis direction from the end surface 104 on the + Y axis direction side.

  The ground via 64 that penetrates the cover layers 301 and 302 may include the same material as the conductive material included in the shield layer 51. For example, the earth via 64 may include the same material as the conductive material included in the shield layer 51 by filling a part of the shield layer 51 into the through hole 63. The shield layer 51 is connected to the conductive layer 11 and the conductive layer 12 through the earth via 64. The earth via 64 penetrating the cover layers 301 and 302 may be disposed immediately above the ground circuit 40.

  Next, a method for manufacturing the flexible printed wiring board 1 according to Embodiment 1 will be described. FIG. 2 is a flowchart illustrating the method for manufacturing the flexible printed wiring board 1 according to the first embodiment.

  As shown in step S11 of FIG. 2, first, the laminated wiring board 100 is prepared. The laminated wiring board 100 includes a conductive layer 11, an insulating layer 21 provided on the conductive layer 11, a signal circuit 30 provided on the insulating layer 21 and having a portion extending in the X-axis direction, the insulating layer 21, and Insulating layers 22 and 23 provided on the signal circuit 30 and a conductive layer 12 provided on the insulating layer 23 are included.

  Next, as shown in step S12, the shield film 200 is prepared. Specifically, the shield film parts 201 and 202 in which the conductive shield layer 51 is formed on one surface of the insulating insulating coating layer 52 are prepared. Note that the order of step S11 and step S12 may be reversed or simultaneous.

  Next, as shown in step S <b> 13, the laminated wiring board 100 is covered with the shield film 200. Specifically, the lower surface 101 of the multilayer wiring board 100 is covered with the shield layer 51 side of the shield film part 201 via the insulating cover layer 301, and the upper surface 102 of the multilayer wiring board 100 is covered with the insulating cover layer. Cover the shield film portion 202 on the shield layer 51 side via 302. At the same time, at least a part of both end faces of the multilayer wiring board 100 in the Y-axis direction is covered with the shield layer 51 side of the shield film portions 201 and 202. The cover layer 302 is provided with a through hole 63. Further, it is desirable that the cover layer 301 is also provided with a through hole 63.

  Next, as shown in step S14, pressing is performed. For example, heat pressing is performed by applying heat. Specifically, the shield films 201 and 202 covering the laminated wiring board 100 and the laminated wiring board 100 are pressed in the vertical direction. For example, the hot press preferably has a temperature of about 150 to 190 [° C.], a pressure of about 1 to 3 [MPa], and a time of about 1 to 60 [min]. Thereby, the laminated wiring board 100, the cover layers 301 and 302, and the shield film parts 201 and 202 are pressure-bonded. At this time, the through hole 63 is filled with a part of the shield layer 51. In this way, the flexible printed wiring board 1 can be manufactured.

  Next, a comparative example will be described before describing the effects of the present embodiment. Then, the effect of this embodiment is demonstrated compared with a comparative example. FIG. 3 is a cross-sectional view illustrating a flexible printed wiring board 1110 according to a comparative example. As shown in FIG. 3, in the flexible printed wiring board 1110, both end surfaces of the laminated wiring board 100 are not covered with the shield film 200. Therefore, leakage of radiation noise 1012 from both end faces of the laminated wiring board 100 cannot be suppressed.

  FIG. 4 is a cross-sectional view illustrating the main part of the flexible printed wiring board 1 according to the first embodiment. As shown in FIG. 4, the flexible printed wiring board 1 of this embodiment includes not only the upper surface 102 and the lower surface 101 of the multilayer wiring board 100 but also both end surfaces of the multilayer wiring board 100, that is, the end surface 103 on the −Y axis direction side. And the end surface 104 on the + Y axis direction side is covered with the shield layer 51. Therefore, leakage of radiation noise from both end faces of the laminated wiring board 100 can be suppressed.

  Further, the signal circuit 30 through which the high-frequency signal flows is arranged so as to be sandwiched between the ground circuits 40. Thereby, the shielding property of radiation noise can be improved.

  The conductive layer 11 and the shield layer 51 are disposed below the signal circuit 30, and the conductive layer 12 and the shield layer 51 are disposed above the signal circuit 30. Thus, since it is shielded doubly, the shielding property can be improved.

  Below the signal circuit 30, the conductive layer 11 and the shield layer 51 are connected by an earth via 64. Thereby, the conductive layer 11 and the shield layer 51 can be reliably set to the same potential. In addition, above the signal circuit 30, the conductive layer 12 and the shield layer 51 are connected by a ground via 64. Thereby, the conductive layer 12 and the shield layer 51 can be reliably set to the same potential. Therefore, the shielding property of radiation noise can be improved.

  The earth via 64 penetrates to the conductive layers 11 and 12 and does not penetrate to the ground circuit 40. The ground via 64 is formed in the through hole 63 formed in the cover layers 301 and 302. Therefore, since the earth via 64 does not need to penetrate the conductive layers 11 and 12, the manufacturing can be facilitated and the cost can be reduced. When the conductive layer 11 and the conductive layer 12 are not formed from a conductive adhesive layer but are formed from a metal layer such as FCCL copper foil, the conductive layer 11 and the conductive layer 12 are formed from a conductive adhesive layer. Compared to the above, the shielding property can be improved. This also applies when the metal layer 53 is disposed between the shield layer 51 and the insulating coating layer 52 in the shield film 200 as shown in FIG. That is, the metal layer 53 of the shield film 200 can improve the shielding property.

  Further, the fact that the conductive layers 11 and 12 are metal layers brings about an effect that the transmission characteristics in the high frequency region are excellent in addition to the shielding effect. As a result, it is possible to cope with higher frequency of the signal, and hence higher speed of data processing. Due to such merits, that is, high shielding properties and excellent transmission characteristics, the signal propagating through the flexible printed wiring board 1 (FPC) can be protected from external noise and signal degradation during propagation, It can also be used in places that could not be used in the past.

  Furthermore, since the shield layer 51 of the shield film 200 is formed from a conductive adhesive layer, the adhesion to the laminated wiring board 100 can be improved.

  The earth via 64 is formed immediately above or directly below the ground circuit 40. Therefore, the space potential between the conductive layer 11 and the conductive layer 12, the space potential between the conductive layer 11 and the shield layer 51, and the space potential between the conductive layer 12 and the shield layer 51 are made equal. Can be improved and the shielding property can be improved.

  The shield film portion 201 and the shield layer 51 of the shield film portion 202 have portions extending from both end surfaces of the laminated wiring board 100 in the outer Y-axis direction. Thereby, the leakage of the radiation noise from the both end surfaces of the laminated wiring board 100 can be suppressed.

(Embodiment 2)
Next, a flexible printed wiring board according to the second embodiment will be described. FIG. 5 is a cross-sectional view illustrating a flexible printed wiring board according to the second embodiment. As shown in FIG. 5, the flexible printed wiring board 2 is different from the flexible printed wiring board 1 in the configuration of the shield film 200. That is, the flexible printed wiring board 2 includes a single shield film 203 instead of the shield film portions 201 and 202 of the first embodiment. Since the configurations of the multilayer wiring board 100, the cover layer 301, and the cover layer 302 are the same as those in the first embodiment, the description thereof is omitted.

  In the flexible printed wiring board 2, the laminated wiring board 100 is covered with a single shield film 203. For example, the shield film 203 starts to cover the center portion of the lower surface 101 of the laminated wiring board 100. The covering start portion is referred to as a starting point portion 203a. The shield film 203 covers the end surface 103, the upper surface 102, and the end surface 104 of the laminated wiring board 100 in order from the starting point portion 203 a, and overlaps the starting point portion 203 a at the central portion of the lower surface 101 of the laminated wiring board 100. A portion that overlaps the start point portion 203a and finishes winding is referred to as an end point portion 203b.

  In the central portion of the lower surface 101 of the multilayer wiring board 100, the end point 203b overlaps the start point 203a. Therefore, in the overlapped portion, the shield layer 51 of the end point portion 203b overlaps the insulating coating layer 52 of the start point portion 203a. Thus, in the flexible printed wiring board 2, the shield film 203 has a portion in which the insulating coating layer 52 is sandwiched between the shield layer 51 and the shield layer 51 by overlapping.

  Further, the shield layer 51 of the shield film 203 has portions extending in the Y-axis direction on the outer side from both end surfaces of the laminated wiring board 100 in the Y-axis direction. The shield layer 51 has a portion extending in the −Y axis direction from the end surface 103 on the −Y axis direction side, and a portion extending in the + Y axis direction from the end surface 104 on the + Y axis direction side. For example, when the laminated wiring board 100 and the shield film 203 covering the laminated wiring board 100 are hot-pressed in the vertical direction, the shield layer 51 extends from both end surfaces of the laminated wiring board 100 in the Y-axis direction to the outer Y-axis direction. Can be.

  Next, a method for manufacturing the flexible printed wiring board 2 according to Embodiment 2 will be described. The manufacturing method of the flexible printed wiring board 2 of this embodiment differs from the manufacturing method of Embodiment 1 in the process of preparing the shield film 200 and the process of covering the laminated wiring board 100 with the shield film 200.

  In the second embodiment, in the step of preparing the shield film 200, instead of preparing the shield film portions 201 and 202, one shield film 203 is prepared. The shield film 203 is obtained by forming a conductive shield layer 51 on one surface of an insulating insulating coating layer 52.

  Further, in the step of covering the laminated wiring board 100 with the shield film 203, the shielding film 203 is arranged from the lower surface 101 of the laminated wiring board 100 in the order of the end surface 103 on the −Y axis direction side, the upper surface 102, and the end surface 104 on the + Y axis direction side. The multilayer wiring board 100 is covered so as to be wound around. Then, by overlapping the shield film 203, a portion in which the insulating coating layer 52 is sandwiched between the shield layer 51 and the shield layer 51 is provided. In this way, the flexible printed wiring board 2 can be manufactured.

  According to the flexible printed wiring board 2 of the present embodiment, the shield film 203 covers the periphery of the laminated wiring board 100 so as to be wound. Therefore, leakage of radiation noise can be suppressed. Moreover, the start point part 203a and the end point part 203b have overlapped in the junction part of the shield film 203. FIG. Thereby, the leakage of the radiation noise from a junction part can be suppressed. Other configurations and effects are included in the description of the first embodiment.

(Embodiment 3)
Next, the flexible printed wiring board 3 according to Embodiment 3 will be described. FIG. 6 is a cross-sectional view illustrating a flexible printed wiring board according to the third embodiment.

  As shown in FIG. 6, the flexible printed wiring board 3 includes an extended conductive layer 71 extending from the conductive layer 11 in the Y-axis direction, and an extended insulating layer 72 extending from the insulating layer 21 in the Y-axis direction. The extending portion 70 is further provided. Therefore, the extending portion 70 is provided on the −Y axis direction side from the end surface 103 of the multilayer wiring board 100 and on the + Y axis direction side from the end surface 104. The extending portion 70 extends outward in the Y-axis direction from both end surfaces of the insulating layer 22, the insulating layer 23, and the conductive layer 12. In addition, when the conductive layer 11 and the insulating layer 21 are formed using the double-sided FCCL, the extending portion 70 may include a conductive layer remaining after patterning of the signal circuit 30 and the ground circuit 40 on the double-sided FCCL.

  The plurality of connection vias 74 penetrate through the extending portion 70. The plurality of connection vias 74 are arranged along the X-axis direction in the extending portion 70. The plurality of connection vias 74 may include the same material as that included in the shield layer 51. The plurality of connection vias 74 may include a conductive material plated on the inner surface of the through hole 73 that penetrates the extending portion 70.

  The shield film 200 includes a shield film portion 201 that covers the lower surface 101 of the laminated wiring board 100 and a shield film portion 202 that covers the upper surface 102. The shield film part 201 covers both end faces of the cover layer 301 in the Y-axis direction. The shield film part 201 covers the lower surface of the extending part 70. The shield film portion 202 covers both end surfaces of the insulating layer 22, the insulating layer 23, the conductive layer 12, and the cover layer 302 in the Y-axis direction. The shield film part 202 covers the upper surface of the extending part 70. Therefore, the shield layer 51 of the shield film part 201 and the shield film part 202 has a portion extending from the both end surfaces of the laminated wiring board 100 in the Y-axis direction to the outer Y-axis direction. Further, the shield film part 202 is connected to the shield film part 201 via a plurality of connection vias 74 penetrating the extending part 70.

  Next, a method for manufacturing the flexible printed wiring board 3 according to Embodiment 3 will be described. The manufacturing method of this embodiment differs from the manufacturing method of Embodiment 1 in the step of preparing the laminated wiring board 100, the step of covering the laminated wiring board 100 with the shield film 200, and the step of pressing.

  In the manufacturing method of the third embodiment, in the step of preparing the laminated wiring board 100, the extended conductive layer 71 extending from the conductive layer 11 in the Y-axis direction and the extended insulating layer 72 extending from the insulating layer 21 in the Y-axis direction. Are also prepared. A plurality of through holes 73 are formed in the extending portion 70. The inner surfaces of the plurality of through holes 73 may be plated with a conductive material. Further, the inside of the plurality of through holes 73 may be filled with a conductive paste.

  In the step of covering the laminated wiring board 100 with the shield film 200, the lower surface 101 of the laminated wiring board 100 is covered on the shield layer 51 side of the shield film portion 201. At the same time, both end surfaces of the cover layer 301 in the Y-axis direction and the lower surface of the extending portion 70 are covered with the shield layer 51 side of the shield film portion 201. Further, the upper surface 102 of the laminated wiring board 100 is covered with the shield layer 51 side of the shield film portion 202. At the same time, both end surfaces of the insulating layer 22, the insulating layer 23, the conductive layer 12, and the cover layer 302 in the Y-axis direction and the upper surface of the extending portion 70 are covered with the shield layer 51 side of the shield film portion 202.

  In the pressing step, the through hole 73 is filled with a part of the shield layer 51. When the inner surfaces of the plurality of through holes 73 are plated with a conductive material, the through holes 73 do not have to be partially filled with the shield layer 51.

  According to the flexible printed wiring board 3 of this embodiment, since it has the extension part 70, handling can be made easy. Further, the shield films 201 and 202 can be easily attached. Other configurations and effects are included in the descriptions of the first and second embodiments.

(Modification)
Next, a modification of the third embodiment will be described. 7 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 1 of Embodiment 3, and FIG. 8 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 2 of Embodiment 3. FIG. 9 is a cross-sectional view illustrating a flexible printed wiring board according to Modification 3 of Embodiment 3.

  As shown in FIG. 7, in the flexible printed wiring board 3a, the laminated wiring board 100a includes a conductive layer 11, an insulating layer 21a, an insulating layer 22a, and a conductive layer 12. A signal circuit 30 and a ground circuit are provided between the insulating layer 21a and the insulating layer 22a. The insulating layer 21a and the insulating layer 22a contain a liquid crystal polymer as a material.

  The laminated wiring board 100a may be formed using, for example, a double-sided FCCL and a single-sided FCCL. The insulating base material layers of the double-sided FCCL and the single-sided FCCL contain a liquid crystal polymer as a material. The copper foil on one side of the double-sided FCCL is used as the conductive layer 11, and the insulating base material layer is used as the insulating layer 21a. The copper foil on the other surface is patterned and used as the signal circuit 30 and the ground circuit 40. Moreover, the copper foil on one surface of the single-sided FCCL is used as the conductive layer 12, and the insulating base material layer is used as the insulating layer 22a. When the double-sided FCCL and single-sided FCCL are used, the laminated wiring board 100a is formed as follows. That is, the signal circuit 30 and the ground circuit 40 are formed by patterning the other surface of the double-sided FCCL. Next, the insulating base layer side of the single-sided FCCL is bonded to the patterned surface of the double-sided FCCL. Thereby, the laminated wiring board 100a is formed.

  In the flexible printed wiring board 3a, the extending part 70 includes an extending conductive layer 71 and an extending insulating layer 72a. The extended conductive layer 71 and the extended insulating layer 72a contain the same material as that of the conductive layer 11 and the insulating layer 21a. When the conductive layer 11 and the insulating layer 21a are formed using the double-sided FCCL, the extending part 70 may include a conductive layer remaining after patterning of the signal circuit 30 and the ground circuit 40 on the double-sided FCCL.

  Instead of the cover layer 301, a resist layer 303 is formed on the lower surface 101 of the multilayer wiring board 100a. Further, a resist layer 304 is formed on the upper surface 102 of the multilayer wiring board 100a instead of the cover layer 302. A through hole 63 is formed in the resist layer 304. An earth via 64 is formed inside the through hole 63. The shield layer 51 in the shield film portions 201 and 202 covers the laminated wiring board 100a via the resist layers 303 and 304.

  The resist layers 303 and 304 may be omitted as in the flexible printed wiring board 3b shown in FIG. In this case, the shield layer 51 in the shield film portions 201 and 202 directly covers the laminated wiring board 100a without using the cover layers 301 and 302 or the resist layers 303 and 304. Therefore, since the surfaces of the conductive layers 11 and 12 are covered with the shield layer 51 formed from the conductive adhesive layer, the adhesion can be improved. Moreover, since the conductive layers 11 and 12 are formed from a metal layer such as a copper foil of FCCL, as described above, the shielding effect and the transmission characteristic effect can be improved. Other configurations and effects are included in the descriptions of the first to third embodiments.

  Like the flexible printed wiring board 3c shown in FIG. 9, the cover layers 301 and 302 of the flexible printed wiring board 1 according to Embodiment 1 may be omitted. That is, the flexible printed wiring board 3c includes a laminated wiring board 100 extending in the X-axis direction and a shield film 200 in which a conductive shield layer 51 is formed on one surface of an insulating insulating coating layer 52, and includes a laminated wiring board. A shield film 200 that covers the upper surface 102 and the lower surface 101 of the board 100 on the shield layer 51 side, and covers at least a part of both end faces of the laminated wiring board 100 in the Y-axis direction on the shield layer 51 side. . Here, the laminated wiring board 100 is insulated from the conductive layer 11, the insulating layer 21 provided on the conductive layer 11, the signal circuit 30 provided on the insulating layer 21 and having a portion extending in the X-axis direction. The insulating layer 22 provided on the layer 21 and the signal circuit 30 and the conductive layer 12 provided on the insulating layer 22 are included. The shield layer 51 is connected to the conductive layer 11 and the conductive layer 12.

  Even in such a configuration, the surfaces of the conductive layers 11 and 12 are covered with the shield layer 51 formed of the conductive adhesive layer, so that the adhesion can be improved. Further, since the conductive layers 11 and 12 are formed of a metal layer such as a copper foil of FCCL, the shielding property can be improved. Other configurations and effects are included in the descriptions of the first to third embodiments.

<Example>
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. First, a method for producing a measurement sample will be described.

[Measurement sample preparation]
(Example 1)
The laminated wiring board 100 is manufactured using the double-sided FCCL and the single-sided FCCL. The double-sided FCCL is obtained by laminating a rolled copper foil having a thickness of 12 [μm] on both surfaces of a polyimide film having a thickness of 50 [μm]. Signal circuits 31 and 32 and ground circuits 41 and 42 are formed on one rolled copper foil in the double-sided FCCL. The lengths of the signal circuits 31 and 32 and the ground circuits 41 and 42 in the X-axis direction are, for example, 10 [cm]. The ground circuits 41 and 42 are formed outside the both sides of the signal circuits 31 and 32 in parallel with the signal circuits 31 and 32. Note that the circuit appearance and tolerance inspection specifications are the JPCA standard (JPCA-DG02). The other rolled copper foil in the double-sided FCCL becomes the conductive layer 11. The polyimide film in the double-sided FCCL becomes the insulating layer 21.

  Single-sided FCCL is obtained by laminating a rolled copper foil with a thickness of 12 [μm] on one side of a polyimide film with a thickness of 12.5 [μm]. The rolled copper foil in the single-sided FCCL is the conductive layer 12. The polyimide film in the single-sided FCCL is the insulating layer 23.

  Next, the polyimide film side of the single-sided FCCL and the circuit forming surface side of the double-sided FCCL are laminated via an insulating adhesive. Then, pressure bonding is performed under a condition of 30 [min] at a temperature of 150 [° C.] and a pressure of 2.0 [MPa]. The insulating adhesive becomes the insulating layer 22 having a thickness of 35 [μm].

  Then, a through hole having a diameter of 0.1 [mm] (not shown) is provided, and then the electroless plating process is performed, and then the electroplating process is performed to thereby form the conductive layers 11 and 12 and the ground circuits 41 and 42. Ensure continuity.

  Further, cover layers 301 and 302 are attached to the outer surfaces of the conductive layers 11 and 12 so as to cover the conductive layers 11 and 12, and 30 [min] at a temperature of 150 [° C.] and a pressure of 2.0 [MPa]. ] Under the conditions of]. The cover layers 301 and 302 are composed of a polyimide film having a thickness of 12.5 [μm] and an insulating adhesive layer having a thickness of 15 [μm]. The cover layers 301 and 302 are provided with through holes 63. Thereafter, nickel plating (not shown) is performed on the circuit formation surface exposed in the through hole 63 and the conductive layers 11 and 12, and then gold plating (not shown) is performed. Then, cutting is performed at a position of 300 [μm] on the −Y axis direction side from the ground circuit 41 and 300 [μm] on the + Y axis direction side from the ground circuit 42. Thereby, the laminated wiring board 100 is formed.

  Next, two types of shield films 200 shown in FIG. 13 are prepared for type A, and the respective shield layers 51 are arranged on the inner side so as to cover both end surfaces 103 and 104 of the laminated wiring board 100 in the Y-axis direction. Pressure bonding is performed at a temperature of [° C.] and a pressure of 2.0 [MPa] under a condition of 30 [min]. Then, the shield film 200 is cut at a position of 1000 [μm] from both end faces of the laminated wiring board 100 in the + Y axis direction and the −Y axis direction side. Thereby, the part which only the shield film 200 overlapped with the both ends of the Y-axis direction of the shield film 200 is made to have a width of 1000 [μm]. In this way, the flexible printed wiring board 1 is obtained.

  As shown in FIG. 13, in the type A shield film 200, the thickness of the insulating coating layer 52 is 15 [μm], and the thickness of the shield layer 51 made of an insulating adhesive layer is 7 [μm]. μm]. The conductive filler ratio of the insulating adhesive layer is 80 [wt%]. The type A shield film 200 does not include the metal layer 53. On the other hand, in the type B shield film 200, the insulating coating layer 52 has a thickness of 15 μm, and the shield layer 51 includes an insulating adhesive layer and a metal layer 53. The thickness of the insulating adhesive layer is 7 [μm]. The conductive filler ratio of the insulating adhesive layer is 80 [wt%]. The thickness of the metal layer 53 is 3 [μm]. The metal layer 53 includes, for example, electrolytic copper foil.

(Examples 2 to 9, Comparative Examples 1 and 2)
FIG. 14 is a diagram illustrating the configuration and measurement results of Examples 1 to 10. As shown in FIG. 14, except for changing the width of the overlapping portion of only the shield film determined by the configuration of the flexible wiring board (FPC) of Example 1, the type of the shield film, and the cutting position after the shield film 200 is attached. The same sample preparation as Example 1 is performed, and the flexible printed wiring boards of Examples 2-9 and Comparative Examples 1 and 2 are obtained.

  Example 2 differs from Example 1 in the cutting position of the shield film 200 in the Y-axis direction, and is cut at 5000 [μm] from both end faces of the laminated wiring board 100. Therefore, the feature of Example 2 is that the width of the portion where only the shield films 200 extending from both end faces of the laminated wiring board 100 overlap is 5000 [μm]. Other configurations are the same as those in the first embodiment.

  Example 3 differs from Example 1 in the cutting position of the shield film 200 in the Y-axis direction, and is cut at 200 [μm] from both end faces of the laminated wiring board 100. Therefore, the feature of Example 3 is that the width of the portion where only the shield films 200 extending from both end faces of the laminated wiring board 100 overlap is 200 [μm]. Other configurations are the same as those in the first embodiment.

  Example 4 differs from Example 1 in the cutting position of the shield film 200 in the Y-axis direction, and is cut at 100 [μm] from both end faces of the laminated wiring board 100. Therefore, the feature of Example 4 is that the width of the portion where only the shield films 200 extending from both end faces of the laminated wiring board 100 overlap is 100 [μm]. Other configurations are the same as those in the first embodiment.

  Example 5 differs from Example 1 in the type of shield film 200, and type B shield film 200 is used. Therefore, the feature of Example 5 is that the type B shield film 200 is used. Other configurations are the same as those in the first embodiment.

  The sixth embodiment is different from the first embodiment in that an extending portion 70 is provided on the multilayer wiring board 100 as shown in FIG. Therefore, the characteristic of Example 6 is the extension part 70 shown in FIG. Other configurations are the same as those in the first embodiment.

  Example 7 is different from Example 6 in that the insulating layer 21a and the insulating layer 22a contain a liquid crystal polymer as a material, as shown in FIG. Another difference is that resist layers 303 and 304 are used instead of the cover layers 301 and 302. Therefore, the features of Example 7 are the insulating layers 21a and 22a and the resist layers 303 and 304 shown in FIG. The other configuration is the same as that of the sixth embodiment.

  Example 8 is different from Example 7 in that resist layers 303 and 304 are omitted as shown in FIG. Therefore, the characteristic of Example 8 is the structure of FIG. The other configuration is the same as that of the seventh embodiment.

  Example 9 is different from Example 1 in that the cover layers 301 and 302 of the flexible wiring board 1 are omitted as shown in FIG. Therefore, the feature of the ninth embodiment is the configuration of FIG. Other configurations are the same as those in the first embodiment.

  In Comparative Example 1, the width of the overlapping portion of only the shield film that covers the flexible printed wiring board 1001 shown in FIG. 10 is 0 [μm], that is, the shield film and the laminated wiring board have the same cross section in the Y-axis direction.

  Comparative Example 2 is a case of the flexible printed wiring board shown in FIG. 3 and is not covered with a shield film.

(Example 10)
One shield film 203 is covered so as to wrap around the laminated wiring board 100, and the start point 203 a and the end point 203 b of the shield film 203 overlap each other. When the shield film 203 and the laminated wiring board 100 are hot-pressed in the vertical direction, the width of the portion where only the shield film 203 overlaps both end faces of the laminated wiring board 100 is set to 1000 [μm].

  The tenth embodiment is characterized by having a start point portion 203a and an end point portion 203b as shown in FIG. Other configurations are the same as those in the first embodiment.

[Evaluation of radiation noise]
A signal in the range of 1 MHz to 20 GHz is sent to the obtained flexible printed wiring board using a network analyzer, and radiation noise via the near magnetic field probe is measured. As for the probe position at the time of measurement, the X-axis direction is a position +20 [mm] from the connection point with the high-frequency measuring device on the flexible printed wiring board, the Y-axis direction is a cross-sectional portion obtained by cutting the shield film, and the Z-axis direction. The direction is a position of +100 [μm] from the upper part of the flexible printed wiring board. In Examples 1 to 10 and Comparative Examples 1 and 2, the width of the signal circuits 31 and 32 is 70 [μm], the interval between the signal circuits 31 and 32 is 100 [μm], and the ground circuits 41 and 42 The width is 100 [μm], and the distance between the ground circuit 41 and the signal circuit 31 is 400 [μm].

  Shields how much the output signal from the high frequency measuring instrument to the flexible printed wiring board and how much the signal is radiated from the flexible printed wiring board and input to the high frequency measuring instrument via the near-field probe is attenuated. Measured as effect [dB]. The larger this attenuation, that is, the shielding effect [dB], means that the radiation noise can be shielded. Therefore, the larger the shielding effect [dB], the better the shielding property, and the closer to 0 [dB], the more the radiation noise and the lower the shielding property of the flexible printed wiring board. In addition, the radiation noise measurement is performed in a frequency range of 300 kHz to 20 GHz in an atmosphere having a temperature of 25 ° C. and a relative humidity of 50%.

  As shown in FIG. 14, in Example 1, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 93 [dB], 84 [dB], and 78 [dB], respectively. In Example 2, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 93 [dB], 84 [dB], and 78 [dB], respectively. In Example 3, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 93 [dB], 84 [dB], and 78 [dB], respectively.

  In Example 4, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 88 [dB], 81 [dB], and 76 [dB], respectively. In Example 5, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 96 [dB], 89 [dB], and 87 [dB], respectively. In Example 6, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 84 [dB], 77 [dB], and 73 [dB], respectively.

  In Example 7, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 83 [dB], 77 [dB], and 73 [dB], respectively. In Example 8, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 83 [dB], 77 [dB], and 73 [dB], respectively. In Example 9, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 83 [dB], 77 [dB], and 73 [dB], respectively.

  In Example 10, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 94 [dB], 85 [dB], and 78 [dB], respectively. In Comparative Example 1, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 73 [dB], 69 [dB], and 66 [dB], respectively. In Comparative Example 2, the shielding effects at 1 [GHz], 2 [Ghz], and 3 [GHz] are 73 [dB], 70 [dB], and 76 [dB], respectively.

  FIG. 15 is a graph illustrating the measurement results of Examples 1 to 10, in which the horizontal axis indicates the example and the vertical axis indicates the shielding effect. As shown in FIG.14 and FIG.15, compared with the comparative examples 1 and 2 of Examples 1-10, radiation noise is reduced. Hereinafter, the viewpoint of the structure of the FPC, the type of the shield film, and the width where only the shield films overlap will be described.

<Configuration of FPC>
As shown in FIGS. 14 and 15, the laminated wiring board 100 in the flexible wiring board has a greater shielding effect when it does not have the extending portion 70. However, even if it has the extension part 70, a shield effect is larger than a comparative example. In the case of Example 10 wound with one shield film 203, the shielding effect is larger in the range of 1 to 2 [GHz] than when two shield sheets 200 are used.

<Types of shield film>
As shown in Example 1 and Example 5, the shielding effect when the type B shield film is used is larger than that when the type A shield film is used. Further, when the type B shield film is used, the shielding effect is large over a range of 1 to 3 [GHz].

<Width where only shield films overlap>
When the width of the part where only the shield films overlap is 200 [μm] or more, the shielding effect is larger than the case of 100 [μm]. When the width of the part where only the shield films overlap is 200 to 1000 [μm], there is no significant difference in the shielding effect in the range of 1 to 3 [GHz].

[Handling evaluation]
The obtained flexible printed wiring board was cut to a length of about 30 mm to prepare a sample piece, and then the sample piece was sealed in 10 containers, and the stroke was 40 [mm] and the speed was 120 [times / min. ] To evaluate the resistance of the flexible printed wiring board when shaken for 10 [min]. Excellent (◎) indicates no damage or damage, and scratches are observed, but no damage is indicated (Good), and 10 out of 10 damages are good (△) Show.

  As shown in FIG. 14, the flexible wiring boards of Examples 6 to 9 have excellent handling properties. On the other hand, the flexible wiring board of Example 2 has good handling properties and is good. Other than that, it is good.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, you may mutually combine each member which comprises the flexible printed wiring board of Embodiment 1-3 and the modifications 1-2.

  Moreover, you may connect the flexible printed wiring board of Embodiment 1-3 and the modifications 1-2 to an electronic member. The electronic member includes a member used for communication equipment. The electronic member to which the flexible printed wiring boards of Embodiments 1 to 3 and Modifications 1 and 2 are connected effectively suppresses high frequency noise radiated from the flexible printed wiring board, and simultaneously shields high frequency noise from the outside. be able to. Moreover, the influence of the high frequency noise radiated | emitted from the flexible printed wiring board is reduced in the communication apparatus to which the flexible printed wiring board of Embodiment 1-3 and the modification 1-2 was connected.

  The conductive layer 11 and the conductive layer 12 are also referred to as a first conductive layer and a second conductive layer. The insulating layer 21 is referred to as a first insulating layer, and either the insulating layer 22 or the insulating layer 23 is also referred to as a second insulating layer. The cover layer 301 and the cover layer 302 are also referred to as a first cover layer and a second cover layer. The shield film part 201 and the shield film part 202 are also referred to as a first shield film part and a second shield film part.

1, 2, 3, 3a, 3b Flexible printed wiring board 11, 12 Conductive layer 21, 22, 23 Insulating layer 30, 31, 32 Signal circuit 40, 41, 42 Ground circuit 51 Shield layer 52 Insulating coating layer 53 Metal layer 61 Coverlay 62 Insulating adhesive layer 63 Through-hole 64 Ground via 70 Extension portion 71 Extension conductive layer 72, 72a Extension insulation layer 73 Through-hole 74 Connection via 100, 100a, 100b Multilayer wiring board 101 Lower surface 102 Upper surface 103, 104 End face 200, 203 Shield film 201, 202 Shield film part 203a Start point part 203b End point part 301, 302 Cover layer 303, 304 Resist layer 1001 Flexible printed wiring board 1002 Insulating layer 1003 Signal circuit 1004 Ground circuit 1005, 1006 Insulating layer 1007 Conductive layer 1008 insulation Covering layer 1009 Shield film 1010 Through hole 1011 Via 1012 Radiation noise 1021 Flexible flat cable 1022 Electromagnetic wave absorber 1023 Thermosetting adhesive 1110 Flexible printed wiring board

Claims (18)

A laminated wiring board extending in one direction;
A shield film in which a conductive shield layer is formed on one side of an insulating insulating coating layer, the upper surface and the lower surface of the laminated wiring board being covered with the shield layer side, and the upper surface of the laminated wiring board The shield film covering at least a part of both end faces in the other direction perpendicular to the one direction in a plane parallel to the shield layer side;
With
The laminated wiring board is
A first conductive layer;
A first insulating layer provided on the first conductive layer;
A signal circuit provided on the first insulating layer and having a portion extending in the one direction;
A second insulating layer provided on the first insulating layer and the signal circuit;
A second conductive layer provided on the second insulating layer;
Including
The shield layer is connected to the second conductive layer;
Flexible printed wiring board. An insulating first cover layer provided between the lower surface and the shield layer covering the lower surface;
An insulating second cover layer provided between the upper surface and the shield layer covering the upper surface;
The shield layer is connected to the second conductive layer via an earth via that penetrates the second cover layer, and is connected to the first conductive layer via the earth via that penetrates the first cover layer. Was
The flexible printed wiring board according to claim 1. The both end faces are covered with the shield layer from the first conductive layer to the second conductive layer,
The flexible printed wiring board of Claim 1 or 2. The shield film is
A first shield film portion covering the lower surface;
A second shield film portion covering the upper surface;
Including
The shield layers of the first shield film part and the second shield film part have portions extending in the other direction outside from the both end faces,
The flexible printed wiring board as described in any one of Claims 1-3. The shield film has a portion in which the insulating coating layer is sandwiched between the shield layer and the shield layer by overlapping,
The flexible printed wiring board as described in any one of Claims 1-3. The shield layer has a portion extending in the other direction outside from the both end faces,
The flexible printed wiring board according to claim 5. An extended portion including: an extended conductive layer extending from the first conductive layer in the other direction; and an extended insulating layer extending from the first insulating layer in the other direction;
The shield film is
A first shield film portion covering the lower surface;
A second shield film portion covering the upper surface;
Including
The shield layers of the first shield film part and the second shield film part have portions extending in the other direction outside from the both end faces,
The second shield film part is connected to the first shield film part via a plurality of connection vias penetrating the extending part.
The flexible printed wiring board according to claim 1. The plurality of connection vias include the same material as that included in the shield layer.
The flexible printed wiring board according to claim 7. The plurality of connection vias include a conductive material plated on an inner surface of a through hole penetrating the extending portion or a conductive material filled in the through hole.
The flexible printed wiring board according to claim 7. The laminated wiring board is
A first ground circuit and a second ground circuit provided on the first insulating layer and having a portion extending in the one direction;
The second insulating layer is provided on the first ground circuit and the second ground circuit,
The signal circuit is disposed between the first ground circuit and the second ground circuit;
The flexible printed wiring board as described in any one of Claims 1-9. An earth via penetrating the insulating second cover layer provided between the upper surface and the shield layer covering the upper surface is disposed immediately above the second ground circuit.
The flexible printed wiring board according to claim 10.   The flexible printed wiring board according to claim 1, wherein the shield film includes a metal layer formed between the insulating coating layer and the shield layer. A first conductive layer;
A first insulating layer provided on the first conductive layer;
A signal circuit provided on the first insulating layer and having a portion extending in one direction;
A second insulating layer provided on the first insulating layer and the signal circuit;
A second conductive layer provided on the second insulating layer;
Preparing a laminated wiring board including:
Preparing a shield film in which a conductive shield layer is formed on one side of an insulating insulating coating layer; and
The lower surface of the laminated wiring board is covered with the shield layer side of the shield film, the upper surface of the laminated wiring board is covered with the shield layer side of the shield film, and parallel to the upper surface of the laminated wiring board. Covering at least a part of both end faces in the other direction orthogonal to the one direction in the plane on the shield layer side of the shield film;
Pressing the shield film covering the laminated wiring board and the laminated wiring board in the vertical direction;
The manufacturing method of the flexible printed wiring board provided with. The shield film is
A first shield film portion covering the lower surface;
A second shield film portion covering the upper surface;
Including
In the step of covering on the shield layer side,
The lower surface is covered with the first shield film part, and the upper surface is covered with the second shield film part,
The manufacturing method of the flexible printed wiring board of Claim 13. In the step of covering on the shield layer side,
Cover the shield film so that the lower surface, one end surface of the both end surfaces, the upper surface, and the other end surface of the both end surfaces are wound in this order.
By overlapping the shield film, so as to have a portion where the insulating coating layer is sandwiched between the shield layer and the shield layer,
The manufacturing method of the flexible printed wiring board of Claim 13. The shield film is
A first shield film portion covering the lower surface;
A second shield film portion covering the upper surface;
Including
In the step of preparing the laminated wiring board,
An extended portion including an extended conductive layer extending in the other direction from the first conductive layer and an extended insulating layer extending in the other direction from the first insulating layer is also prepared,
In the step of covering on the shield layer side,
Covering the lower surface of the lower surface and the extended portion with the first shield film portion, and covering the upper surface and the upper surface of the extended portion with the second shield film portion,
The manufacturing method of the flexible printed wiring board of Claim 13. In the step of covering on the shield layer side,
The lower surface of the multilayer wiring board is covered with the shield layer side of the shield film through an insulating first cover layer, and the upper surface of the multilayer wiring board is covered with an insulating second cover in which a through hole is formed. Cover the shield film on the shield layer side through a layer,
In the pressing step,
Filling the through hole with a part of the shield layer;
The manufacturing method of the flexible printed wiring board as described in any one of Claims 13-16.   The electronic member to which the said flexible printed wiring board as described in any one of the said Claims 1-12 was connected.

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