WO2020090726A1 - Film de blindage électromagnétique, procédé de production de carte de circuit imprimé blindée, et carte de circuit imprimé blindée - Google Patents

Film de blindage électromagnétique, procédé de production de carte de circuit imprimé blindée, et carte de circuit imprimé blindée Download PDF

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Publication number
WO2020090726A1
WO2020090726A1 PCT/JP2019/042153 JP2019042153W WO2020090726A1 WO 2020090726 A1 WO2020090726 A1 WO 2020090726A1 JP 2019042153 W JP2019042153 W JP 2019042153W WO 2020090726 A1 WO2020090726 A1 WO 2020090726A1
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WO
WIPO (PCT)
Prior art keywords
adhesive layer
insulating adhesive
electromagnetic wave
wiring board
printed wiring
Prior art date
Application number
PCT/JP2019/042153
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English (en)
Japanese (ja)
Inventor
晃司 高見
慶彦 青柳
上農　憲治
渡辺　正博
Original Assignee
タツタ電線株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by タツタ電線株式会社 filed Critical タツタ電線株式会社
Priority to CN201980057301.9A priority Critical patent/CN112586103A/zh
Priority to KR1020217015067A priority patent/KR102530878B1/ko
Priority to JP2020553884A priority patent/JP7244534B2/ja
Publication of WO2020090726A1 publication Critical patent/WO2020090726A1/fr

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/0084—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/025—Electric or magnetic properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/28—Applying non-metallic protective coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/28—Applying non-metallic protective coatings
    • H05K3/281—Applying non-metallic protective coatings by means of a preformed insulating foil
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/0088—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a plurality of shielding layers; combining different shielding material structure

Definitions

  • the present invention relates to an electromagnetic wave shield film, a method for manufacturing a shield printed wiring board, and a shield printed wiring board.
  • Flexible printed wiring boards are widely used in electronic devices such as mobile phones, video cameras, and notebook computers, which are rapidly becoming smaller and more sophisticated, in order to incorporate a circuit into a complicated mechanism. Further, by taking advantage of its excellent flexibility, it is also used for connecting a movable part such as a printer head and a control part.
  • electromagnetic wave shielding measures are essential, and even in flexible printed wiring boards used in devices, flexible printed wiring boards that have been subjected to electromagnetic wave shielding measures such as sticking an electromagnetic wave shielding film (hereinafter, (Also referred to as "shield printed wiring board”) has come into use.
  • the electromagnetic wave shielding film includes an outermost insulating layer (protective layer), a shield layer for shielding electromagnetic waves, and an adhesive layer for sticking to a printed wiring board.
  • the electromagnetic shielding film is attached to the flexible printed wiring board so that the adhesive layer of the electromagnetic shielding film contacts the flexible printed wiring board.
  • the ground circuit of the flexible printed wiring board is electrically connected to the external ground of the housing, etc., but the ground circuit of the printed wiring board is connected via the electromagnetic wave shielding film attached to the flexible printed wiring board. It is also practiced to electrically connect this to an external ground.
  • the adhesive layer of the electromagnetic wave shielding film is a conductive adhesive
  • the conductive adhesive is brought into contact with a ground circuit of a flexible printed wiring board, and the adhesive layer is connected to an external ground.
  • the ground circuit of the flexible printed wiring board and the external ground are electrically connected.
  • the conductive adhesive layer of the electromagnetic wave shielding film described in Patent Document 1 is composed of an adhesive resin and a conductive filler, and the conductivity of the conductive adhesive layer is obtained by the conductive filler. That is, electrical contact between the conductive adhesive layer and the ground circuit is obtained by contact between the conductive filler and the ground circuit. On the contact surface between the conductive adhesive and the ground circuit, there is a portion where the conductive filler does not exist. Since there is such a portion, there is a problem that the connection resistance between the conductive adhesive layer and the ground circuit becomes high. Further, since the adhesive resin contains the conductive filler, the relative dielectric constant and dielectric loss tangent of the entire conductive adhesive layer become high. When the relative permittivity and dielectric loss tangent of the conductive adhesive layer increase, there arises a problem that the transmission characteristics deteriorate.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide an electromagnetic wave shield film for producing a shielded printed wiring board in which the connection resistance is sufficiently small, and the transmission characteristics are sufficiently good. Is to provide.
  • the electromagnetic wave shield film of the present invention comprises a protective layer, a shield layer laminated on the protective layer, and an insulating adhesive layer laminated on the shield layer, and the shield layer on the insulating adhesive layer side.
  • Conductive bumps are formed on the first insulating adhesive layer surface on the shield layer side and the second insulating adhesive layer on the opposite side of the first insulating adhesive layer surface.
  • the second insulating adhesive layer surface has a surface roughness (Ra) of 0.5 to 2.0 ⁇ m.
  • the electromagnetic wave shielding film of the present invention includes a base film, a printed circuit including a ground circuit formed on the base film, and a cover lay covering the printed circuit, and the cover lay has an opening for exposing the ground circuit. It will be attached to the formed printed wiring board.
  • the conductive bump penetrates the insulating adhesive layer and comes into contact with the ground circuit.
  • the connection resistance between the ground circuit and the conductive bump can be reduced.
  • the surface roughness (Ra) of the second insulating adhesive layer surface is 0.5 to 2.0 ⁇ m.
  • the surface roughness (Ra) of the surface of the second insulating adhesive layer is in the above range, the conductive bump easily penetrates the insulating adhesive layer. Therefore, the connection resistance between the ground circuit and the conductive bump can be reduced. It is technically difficult to reduce the surface roughness (Ra) of the second insulating adhesive layer surface to less than 0.5 ⁇ m. Where the surface roughness (Ra) of the surface of the second insulating adhesive layer exceeds 2.0 ⁇ m, the conductive bumps are less likely to penetrate the insulating adhesive layer, and the connection resistance between the ground circuit and the conductive bump increases. Is likely to occur.
  • the electromagnetic wave shielding film of the present invention is adhered to the printed wiring board by the insulating adhesive layer. Since the insulating adhesive layer does not contain a conductive substance such as a conductive filler, the relative dielectric constant and the dielectric loss tangent are sufficiently small. Therefore, the shielded printed wiring board manufactured using the electromagnetic wave shielding film of the present invention has good transmission characteristics.
  • the electromagnetic wave shielding film of the present invention it is desirable that a plurality of the conductive bumps be formed. Furthermore, it is desirable that the heights of the plurality of conductive bumps be substantially the same. When the heights of the plurality of conductive bumps are substantially the same, the plurality of conductive bumps evenly penetrate the insulating adhesive layer and easily come into contact with the ground circuit. Therefore, the connection resistance between the ground circuit and the conductive bump can be reduced.
  • the conductive bump may be made of a resin composition and a conductive filler. That is, the conductive bumps may be made of a conductive paste. By using the conductive paste, the conductive bumps can be easily formed at any position in any shape.
  • the distance from the surface of the second insulating adhesive layer to the conductive bumps is preferably 20 ⁇ m or less.
  • the distance from the second insulating adhesive layer surface to the conductive bump is 20 ⁇ m or less, the conductive bump easily penetrates the insulating adhesive layer, and thus the conductive bump easily contacts the ground circuit.
  • the resin constituting the insulating adhesive layer has a relative dielectric constant of 1 to 5 and a dielectric loss tangent of 0.0001 to 0.03 at a frequency of 1 GHz and 23 ° C. desirable. Within such a range, the transmission characteristics of the shield printed wiring board manufactured using the electromagnetic wave shielding film of the present invention can be improved.
  • the method for manufacturing a shielded printed wiring board of the present invention is an electromagnetic wave shield film preparing step of preparing the electromagnetic wave shield film of the present invention, a base film, and a printed circuit including a ground circuit formed on the base film, A cover lay covering the printed circuit, a printed wiring board preparing step of preparing a printed wiring board in which an opening exposing the ground circuit is formed in the cover lay, and a second insulation of the electromagnetic wave shielding film.
  • the printed wiring board Characterized in that it comprises a pressing step of pressing to contact the ground circuit.
  • the method for producing a shield printed wiring board of the present invention is a method for producing a shield printed wiring board using the electromagnetic wave shielding film of the present invention. Therefore, in the obtained shielded printed wiring board, the connection resistance between the ground circuit and the conductive bump is low, and the transmission characteristics are sufficiently good.
  • the shielded printed wiring board of the present invention comprises a base film, a printed circuit including a ground circuit formed on the base film, and a coverlay covering the printed circuit, and the coverlay includes the ground circuit.
  • the conductive bumps of the electromagnetic wave shielding film of the present invention penetrate the insulating adhesive layer and are connected to the ground circuit of the printed wiring board. Therefore, the connection resistance between the ground circuit and the conductive bump is sufficiently low.
  • the electromagnetic wave shielding film and the printed wiring board are adhered by the insulating adhesive layer of the electromagnetic wave shielding film. Since the insulating adhesive layer does not contain a conductive substance such as a conductive filler, the relative dielectric constant and the dielectric loss tangent are sufficiently small. Therefore, the shielded printed wiring board of the present invention has good transmission characteristics.
  • the surface roughness (Ra) of the second insulating adhesive layer surface is 0.5 to 2.0 ⁇ m.
  • the surface roughness (Ra) of the surface of the second insulating adhesive layer is in the above range, the conductive bump easily penetrates the insulating adhesive layer. Therefore, the connection resistance between the ground circuit and the conductive bump can be reduced.
  • the electromagnetic wave shielding film of the present invention will be adhered to the printed wiring board by the insulating adhesive layer. Since the insulating adhesive layer does not contain a conductive substance such as a conductive filler, the relative dielectric constant and the dielectric loss tangent are sufficiently small. Therefore, the shielded printed wiring board manufactured using the electromagnetic wave shielding film of the present invention has good transmission characteristics.
  • FIG. 1 is a sectional view schematically showing an example of the electromagnetic wave shielding film of the present invention.
  • FIG. 2 is a sectional view schematically showing an example of a shielded printed wiring board using the electromagnetic wave shielding film of the present invention.
  • FIG. 3A is a process drawing showing an example of the method of manufacturing the shielded printed wiring board of the present invention in process order.
  • FIG. 3B is a process drawing showing an example of the method for manufacturing the shielded printed wiring board of the present invention in process order.
  • FIG. 3C is a process drawing showing an example of the method for manufacturing the shielded printed wiring board of the present invention in process order.
  • FIG. 3D is a process drawing showing an example of the method for manufacturing the shielded printed wiring board of the present invention in the order of processes.
  • FIG. 4 is a schematic diagram schematically showing a method of measuring the resistance value of the electromagnetic wave shielding film in the connection resistance measurement test.
  • the electromagnetic wave shielding film of the present invention will be specifically described.
  • the present invention is not limited to the following embodiments, and can be appropriately modified and applied without departing from the scope of the present invention.
  • the electromagnetic wave shield film of the present invention comprises a protective layer, a shield layer laminated on the protective layer, and an insulating adhesive layer laminated on the shield layer, and the shield layer on the insulating adhesive layer side.
  • Conductive bumps are formed on the first insulating adhesive layer surface on the shield layer side and the second insulating adhesive layer on the opposite side of the first insulating adhesive layer surface.
  • the second insulating adhesive layer surface has an agent layer surface, and the surface roughness (Ra) of the second insulating adhesive layer surface is 0.5 to 2.0 ⁇ m.
  • FIG. 1 is a sectional view schematically showing an example of the electromagnetic wave shielding film of the present invention.
  • FIG. 2 is a sectional view schematically showing an example of a shielded printed wiring board using the electromagnetic wave shielding film of the present invention.
  • the electromagnetic wave shielding film 10 includes a protective layer 11, a shield layer 12 laminated on the protective layer 11, and an insulating adhesive layer 13 laminated on the shield layer 12. Further, a plurality of conductive bumps 14 are formed on the shield layer 12 on the insulating adhesive layer 13 side.
  • the insulating adhesive layer 13 has a first insulating adhesive layer surface 13a on the shield layer 12 side and a second insulating adhesive layer surface 13b on the opposite side to the first insulating adhesive layer surface 13a,
  • the surface roughness (Ra) of the second insulating adhesive layer surface is 0.5 to 2.0 ⁇ m.
  • the electromagnetic wave shielding film 10 includes a base film 21, a printed circuit 22 including a plurality of ground circuits 22 a formed on the base film 21, and a coverlay 23 covering the printed circuit 22.
  • the cover lay 23 is attached to the printed wiring board 20 in which the opening 23a exposing the ground circuit 22a is formed, and is used for manufacturing the shield printed wiring board 30.
  • the material of the protective layer 11 is not particularly limited, but is preferably composed of a thermoplastic resin composition, a thermosetting resin composition, an active energy ray curable composition, or the like.
  • thermoplastic resin composition is not particularly limited, but is a styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition. , Acrylic resin compositions and the like.
  • thermosetting resin composition is not particularly limited, but an epoxy resin composition, a urethane resin composition, a urethane urea resin composition, a styrene resin composition, a phenol resin composition, a melamine resin composition. And at least one resin composition selected from the group consisting of acrylic resin compositions and alkyd resin compositions.
  • the active energy ray-curable composition is not particularly limited, and examples thereof include a polymerizable compound having at least two (meth) acryloyloxy groups in the molecule.
  • the protective layer 11 may be composed of one type of material alone, or may be composed of two or more types of materials.
  • the protective layer 11 includes a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling agent, a filler, a flame retardant, and a viscosity adjuster. Agents, antiblocking agents, etc. may be included.
  • the thickness of the protective layer 11 is not particularly limited and may be appropriately set as necessary, but is preferably 1 to 15 ⁇ m, more preferably 3 to 10 ⁇ m. When the thickness of the protective layer is less than 1 ⁇ m, the shield layer and the insulating adhesive layer cannot be sufficiently protected because they are too thin. If the thickness of the protective layer is more than 15 ⁇ m, the protective layer is too thick to bend easily, and the protective layer itself is easily damaged. Therefore, it becomes difficult to apply it to a member that requires bending resistance.
  • the shield layer 12 is not particularly limited as long as it is a conductive material as long as it can shield electromagnetic waves, and may be made of, for example, a metal or a conductive resin.
  • the shield layer 12 is made of a metal
  • examples of the metal include gold, silver, copper, aluminum, nickel, tin, palladium, chromium, titanium and zinc. Of these, copper is preferable. Copper is a suitable material for the first shield layer from the viewpoint of conductivity and economy.
  • the shield layer 12 may be made of an alloy of the above metals.
  • the shield layer 12 may be a metal foil or a metal film formed by a method such as sputtering, electroless plating or electrolytic plating.
  • the shield layer 12 When the shield layer 12 is made of a conductive resin, the shield layer 12 may be made of conductive particles and a resin.
  • the conductive particles are not particularly limited, but may be fine metal particles, carbon nanotubes, carbon fibers, metal fibers and the like.
  • the fine metal particles are not particularly limited, but include silver powder, copper powder, nickel powder, solder powder, aluminum powder, silver-coated copper powder obtained by silver-plating copper powder, and polymer particles. Fine particles obtained by coating glass beads or the like with a metal may also be used. Among these, from the viewpoint of economy, it is desirable to use copper powder or silver-coated copper powder that can be obtained at low cost.
  • the average particle diameter D 50 of the conductive particles is not particularly limited, but is preferably 0.5 to 15.0 ⁇ m. When the average particle diameter of the conductive particles is 0.5 ⁇ m or more, the conductivity of the conductive resin becomes good. When the average particle diameter of the conductive particles is 15.0 ⁇ m or less, the conductive resin can be thinned.
  • the shape of the conductive particles is not particularly limited, but can be appropriately selected from spherical, flat, flaky, dendrite, rod-like, fibrous and the like.
  • the blending amount of the conductive particles is not particularly limited, but is preferably 15 to 80% by mass, and more preferably 15 to 60% by mass.
  • the resin is not particularly limited, but a styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition, an amide resin composition.
  • Thermoplastic resin composition such as acrylic resin composition, thermosetting resin such as phenol resin composition, epoxy resin composition, urethane resin composition, melamine resin composition, alkyd resin composition, etc. A resin composition etc. are mentioned.
  • the conductive bump 14 penetrates the insulating adhesive layer 13 and comes into contact with the ground circuit 22a. By designing the conductive bump 14 so as to surely contact the ground circuit 22a, the connection resistance between the ground circuit 22a and the conductive bump 14 can be reduced.
  • the shape of the conductive bump 14 is not particularly limited, but may be a columnar shape such as a cylinder, a triangular prism, a quadrangular prism, or a cone shape such as a cone, a triangular pyramid, or a quadrangular pyramid.
  • the heights of the plurality of conductive bumps 14 be substantially the same.
  • the plurality of conductive bumps 14 evenly penetrate the insulating adhesive layer 13 and easily come into contact with the ground circuit 22a. Therefore, the connection resistance between the ground circuit 22a and the conductive bump 14 can be reduced.
  • the height of the conductive bumps 14 is preferably 1 to 50 ⁇ m, more preferably 5 to 30 ⁇ m.
  • the volume of the conductive bump 14 is preferably 10,000 to 1,000,000 ⁇ m 3 , and more preferably 30,000 to 500,000 ⁇ m 3 .
  • the conductive bumps 14 are preferably made of a resin composition and a conductive filler. That is, the conductive bump 14 may be made of a conductive paste. By using the conductive paste, the conductive bumps 14 can be easily formed in arbitrary positions and in arbitrary shapes. Further, the conductive bump 14 may be formed by screen printing. When the conductive bumps 14 are formed by screen printing using the conductive paste, the conductive bumps 14 can be easily and efficiently formed in arbitrary positions and in arbitrary shapes.
  • the resin composition is not particularly limited, but a styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin.
  • Thermoplastic resin compositions such as compositions, polypropylene resin compositions, imide resin compositions, amide resin compositions, acrylic resin compositions, phenol resin compositions, epoxy resin compositions, urethane resins
  • a thermosetting resin composition such as a composition, a melamine resin composition or an alkyd resin composition can be used.
  • the material of the resin composition may be one type of these alone or a combination of two or more types.
  • the conductive filler is not particularly limited, but may be metal fine particles, carbon nanotubes, carbon fibers, metal fibers or the like.
  • the metal fine particles are not particularly limited, but include silver powder, copper powder, nickel powder, solder powder, aluminum powder, silver-coated copper powder obtained by silver-plating copper powder, and polymer particles. Fine particles obtained by coating glass beads or the like with a metal may also be used. Among these, from the viewpoint of economy, it is desirable to use copper powder or silver-coated copper powder that can be obtained at low cost.
  • the average particle diameter D 50 of the conductive filler is not particularly limited, but is preferably 0.5 to 15.0 ⁇ m.
  • the shape of the conductive filler is not particularly limited, but can be appropriately selected from spherical, flat, flaky, dendrite, rod-shaped, fibrous, and the like.
  • the weight ratio of the conductive filler is preferably 30 to 99%, more preferably 50 to 99%.
  • the conductive bump may be made of metal formed by a plating method, a vapor deposition method or the like.
  • the conductive bumps are preferably made of copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, or an alloy containing any one or more of these. Conventional methods can be used for the plating method and the vapor deposition method.
  • the electromagnetic wave shielding film 10 is adhered to the printed wiring board 20 by the insulating adhesive layer 13. Since the insulating adhesive layer 13 does not contain a conductive substance such as a conductive filler, the relative dielectric constant and the dielectric loss tangent are sufficiently small. Therefore, the shielded printed wiring board 30 manufactured using the electromagnetic wave shielding film 10 has good transmission characteristics.
  • the surface roughness (Ra) of the second insulating adhesive layer surface 13b is 0.5 to 2.0 ⁇ m.
  • the surface roughness (Ra) of the second insulating adhesive layer surface 13b is preferably 0.5 to 1.8 ⁇ m, more preferably 0.5 to 1.5 ⁇ m.
  • the plurality of conductive bumps 14 penetrate the insulating adhesive layer 13 evenly. Therefore, the plurality of conductive bumps 14 evenly contact the plurality of ground circuits 22a. Therefore, the connection resistance between the ground circuit and the conductive bump can be reduced.
  • the surface roughness (Ra) of the second insulating adhesive layer surface 13b can be controlled by, for example, a method of forming the second insulating adhesive layer by laminating or a method of forming by coating.
  • the surface roughness (Ra) of the second insulating adhesive layer surface is measured by using a confocal microscope (Lasertec, OPTELICS HYBRID, objective lens 20 times). After measuring 5 arbitrary points, the data analysis software (LMeye7) was used to measure in accordance with JIS B 0601: 2013. The cutoff wavelength ⁇ c was 0.8 mm.
  • the thickness of the insulating adhesive layer 13 is preferably 5 to 30 ⁇ m, more preferably 8 to 20 ⁇ m. If the thickness of the insulating adhesive layer is less than 5 ⁇ m, the amount of the resin forming the insulating adhesive layer is small, and it is difficult to obtain sufficient adhesive performance. Also, it is easily damaged. When the thickness of the insulating adhesive layer exceeds 30 ⁇ m, the entire thickness becomes thick and the flexibility tends to be lost. Moreover, the conductive bumps are less likely to penetrate the insulating adhesive layer.
  • the distance from the second insulating adhesive layer surface 13b to the conductive bumps 14 is preferably 20 ⁇ m or less, and is 0 to 20 ⁇ m. Is more desirable. Note that the distance from the second insulating adhesive layer surface 13b to the conductive bump 14 being 0 means that the conductive bump 14 is exposed from the second insulating adhesive layer surface 13b. When the distance from the second insulating adhesive layer surface 13b to the conductive bumps 14 is 20 ⁇ m or less, the conductive bumps 14 easily penetrate the insulating adhesive layer 13, so that the conductive bumps 14 contact the ground circuit 22a. Easier to do.
  • the relative dielectric constant of the resin forming the insulating adhesive layer 13 at a frequency of 1 GHz and 23 ° C. is preferably 1 to 5, and more preferably 2 to 4.
  • the dielectric loss tangent of the resin forming the insulating adhesive layer 13 at a frequency of 1 GHz and 23 ° C. is preferably 0.0001 to 0.03, more preferably 0.001 to 0.02. Within such a range, the transmission characteristics of the shielded printed wiring board 30 manufactured using the electromagnetic wave shielding film 10 can be improved.
  • the insulating adhesive layer 13 may be made of a thermosetting resin or a thermoplastic resin.
  • thermosetting resins include phenolic resins, epoxy resins, urethane resins, melamine resins, polyamide resins and alkyd resins.
  • thermoplastic resin include styrene resin, vinyl acetate resin, polyester resin, polyethylene resin, polypropylene resin, imide resin, and acrylic resin.
  • the epoxy resin is more preferably an amide-modified epoxy resin. These resins are suitable as the resin forming the insulating adhesive layer.
  • the material of the insulative adhesive layer may be one of these materials alone, or a combination of two or more thereof.
  • the printed wiring board 20 to which the electromagnetic wave shielding film 10 is attached will be described below.
  • the materials of the base film 21 and the cover lay 23 are not particularly limited, but it is preferable that the materials are engineering plastics.
  • engineering plastics include resins such as polyethylene terephthalate, polypropylene, crosslinked polyethylene, polyester, polybenzimidazole, polyimide, polyimideamide, polyetherimide, and polyphenylene sulfide.
  • a polyphenylene sulfide film is preferable when flame retardancy is required, and a polyimide film is preferable when heat resistance is required.
  • the thickness of the base film 21 is preferably 10 to 40 ⁇ m
  • the thickness of the cover lay 23 is preferably 10 to 30 ⁇ m.
  • the size of the opening 23a is not particularly limited, but is preferably 0.1 mm 2 or more, and more preferably 0.3 mm 2 or more.
  • the shape of the opening 23a is not particularly limited, and may be circular, elliptical, quadrangular, triangular, or the like.
  • the material of the printed circuit 22 and the ground circuit 22a is not particularly limited, and may be a copper foil, a cured product of a conductive paste, or the like.
  • the shielded printed wiring board 30 manufactured by attaching the electromagnetic wave shielding film 10 to the printed wiring board 20 is one aspect of the shielded printed wiring board of the present invention.
  • the shielded printed wiring board 30 shown in FIG. 2 includes a base film 21, a printed circuit 22 including a plurality of ground circuits 22a formed on the base film 21, and a coverlay 23 covering the printed circuit 22.
  • the printed wiring board 20 in which an opening exposing the ground circuit 22a is formed in the coverlay 23, the protective layer 11, the shield layer 12 laminated on the protective layer 11, and the insulating property laminated on the shield layer 12.
  • the shield layer 12 on the insulating adhesive layer 13 side is formed of an electromagnetic wave shield film 10 having a plurality of conductive bumps 14, and the plurality of conductive bumps 14 of the electromagnetic wave shield film 10 are formed. Penetrates through the insulating adhesive layer 13 and is connected to the plurality of ground circuits 22a of the printed wiring board 20.
  • the conductive bumps 14 of the electromagnetic wave shielding film 10 penetrate the insulating adhesive layer 13 and are connected to the ground circuits 22 a of the printed wiring board 20.
  • the surface roughness (Ra) of the second insulating adhesive layer surface 13b is 0.5 to 2.0 ⁇ m. Therefore, the conductive bumps 14 easily penetrate the insulating adhesive layer 13 and come into uniform contact with the ground circuit 22a. Therefore, the connection resistance between the ground circuit 22a and the conductive bump 14 is sufficiently low.
  • the electromagnetic wave shielding film 10 and the printed wiring board 20 are adhered to each other by the insulating adhesive layer 13 of the electromagnetic wave shielding film 10. Since the insulating adhesive layer 13 does not contain a conductive substance such as a conductive filler, the relative dielectric constant and the dielectric loss tangent are sufficiently small. Therefore, the shielded printed wiring board 30 has good transmission characteristics.
  • FIG. 3A, FIG. 3B, FIG. 3C and FIG. 3D are process diagrams showing an example of a method for manufacturing a shield printed wiring board of the present invention in the order of processes.
  • the electromagnetic wave shielding film 10 is prepared. Since the desirable configuration of the electromagnetic wave shielding film 10 has already been described, the description thereof is omitted here.
  • the electromagnetic shielding film 10 is arranged on the printed wiring board 20 so that the second insulating adhesive layer surface 13b of the electromagnetic shielding film 10 contacts the cover lay 23 of the printed wiring board 20. To do. At this time, the conductive bumps 14 are positioned on the ground circuit 22a.
  • the pressurizing conditions include, for example, 1 to 5 Pa and 1 to 60 min.
  • the insulating adhesive layer 13 of the electromagnetic wave shielding film 10 may be cured by heating after or simultaneously with the pressing step.
  • the shield printed wiring board 30 can be manufactured.
  • Example 1 First, as a first release film, a polyethylene terephthalate film having one surface subjected to a release treatment was prepared.
  • an epoxy resin was applied to the release-treated surface of the first release film and heated at 100 ° C. for 2 minutes using an electric oven to form a protective layer having a thickness of 7 ⁇ m. Then, a 2 ⁇ m copper layer was formed on the protective layer by electroless plating. The copper layer becomes a shield layer.
  • a mixture of a cresol novolac type epoxy resin and an isocyanate was mixed with 90 parts by weight of a conductive filler (spherical silver-coated copper powder having an average particle diameter of 5 ⁇ m) to prepare a conductive paste.
  • conductive paste was screen-printed on the copper layer to form conductive bumps.
  • the conductive bump had a conical shape and had a height of 23 ⁇ m and a volume of 100,000 ⁇ m 3 .
  • the shape, height, and volume of the conductive bumps were measured at arbitrary 5 points on the surface of the shield layer on which the bumps were formed, using a confocal microscope (Lasertec, OPTELICS HYBRID, objective lens 20 times). After that, analysis was performed using data analysis software (LMeye7).
  • the binarization parameter is height
  • the automatic threshold algorithm is the Kittler method.
  • a polyethylene terephthalate film having one surface subjected to a release treatment was prepared. Then, the composition for an insulating adhesive layer was applied to the release-treated surface of the second release film and heated at 100 ° C. for 2 minutes using an electric oven to prepare an insulating adhesive layer having a thickness of 9 ⁇ m.
  • the protective layer formed on the first release film and the insulating adhesive layer formed on the second release film are bonded together, and the second release film is peeled off to thereby form the electromagnetic wave shielding film according to Example 1.
  • the second release film is peeled off to thereby form the electromagnetic wave shielding film according to Example 1.
  • the surface roughness (Ra) of the second insulating adhesive layer surface of the electromagnetic wave shielding film according to Example 1 was 0.72 ⁇ m.
  • Example 2 The electromagnetic wave shielding film according to Example 2 was prepared in the same manner as in Example 1 except that the thickness of the insulating adhesive layer was 16 ⁇ m and the surface roughness (Ra) of the second insulating adhesive layer surface was 0.76 ⁇ m. It was made.
  • an epoxy resin was applied to the release-treated surface of the first release film and heated at 100 ° C. for 2 minutes using an electric oven to form a protective layer having a thickness of 7 ⁇ m. Then, a 2 ⁇ m copper layer was formed on the protective layer by electroless plating. The copper layer becomes a shield layer.
  • a mixture of a cresol novolac type epoxy resin and an isocyanate was mixed with 90 parts by weight of a conductive filler (spherical silver-coated copper powder having an average particle diameter of 5 ⁇ m) to prepare a conductive paste.
  • conductive paste was screen-printed on the copper layer to form conductive bumps.
  • the conductive bump had a conical shape and had a height of 23 ⁇ m and a volume of 100,000 ⁇ m 3 .
  • the shape, height, and volume of the conductive bumps were measured at arbitrary 5 points on the surface of the shield layer on which the bumps were formed, using a confocal microscope (Lasertec, OPTELICS HYBRID, objective lens 20 times). After that, analysis was performed using data analysis software (LMeye7).
  • the binarization parameter is height
  • the automatic threshold algorithm is the Kittler method.
  • composition for an insulating adhesive layer was applied onto the copper layer by a bar coater and heated at 100 ° C. for 2 minutes using an electric oven to form an insulating adhesive layer having a thickness of 13 ⁇ m.
  • an electromagnetic wave shielding film according to Comparative Example 1 was produced.
  • the surface roughness (Ra) of the second insulating adhesive layer surface of the electromagnetic wave shielding film according to Comparative Example 1 was 2.59 ⁇ m.
  • FIG. 4 is a schematic diagram schematically showing a method of measuring the resistance value of the electromagnetic wave shielding film in the connection resistance measurement test.
  • the electromagnetic wave shielding film 110 in FIG. 4 schematically shows the electromagnetic wave shielding film according to each example and comparative example.
  • the electromagnetic wave shield film 110 includes a protective layer 111, a shield layer 112 laminated on the protective layer 111, and an insulating adhesive layer 113 laminated on the shield layer 112.
  • the shield layer on the insulating adhesive layer 113 side A plurality of conductive bumps 114 are formed on 112.
  • connection resistance measurement test a base film 121, a plurality of measurement printed circuits 125 formed on the base film 121, and a cover lay 123 that covers the measurement printed circuits 125 are provided.
  • a model board 120 having an opening 123a exposing the measurement printed circuit 125 is prepared.
  • the opening 123a has a circular shape with a diameter of 1 mm.
  • the electromagnetic wave shielding film 110 is arranged on the model substrate 120 so that the conductive bumps of the electromagnetic wave shielding film 110 come into contact with the measurement printed circuit 125, and 170 ° C., 3 MPa, 3 MPa.
  • the electromagnetic wave shielding film 110 was attached to the model substrate 120 by pressurizing and heating at 150 ° C. for 1 hour and then after-curing for 1 hour.
  • the resistance value between the measurement printed circuits 125 of the model substrate 120 to which the electromagnetic wave shielding film 110 was attached after standing at 60 ° C. for 3 days was measured by the resistance meter 150.
  • the reflow resistance of the model substrate 120 to which the electromagnetic wave shielding film 110 was attached after standing at 60 ° C. for 3 days was evaluated.
  • lead-free solder was assumed, and a temperature profile was set such that the shield film in the shielded printed wiring board was exposed to 265 ° C. for 10 seconds.
  • the resistance value between the measurement printed circuits 125 after the reflow process was performed 5 times under these conditions was measured by the resistance meter 150.
  • the heating cycle process imitates a reflow process of mounting an electronic component after attaching the electromagnetic wave shielding film to the printed wiring board.
  • Table 1 shows the resistance values of the electromagnetic wave shielding films according to Examples 1 and 2 and Comparative Example 1 measured by the above method.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
  • Laminated Bodies (AREA)
  • Non-Metallic Protective Coatings For Printed Circuits (AREA)
  • Structure Of Printed Boards (AREA)

Abstract

La présente invention concerne un film de blindage électromagnétique pour la production d'une carte de circuit imprimé blindée qui présente une résistance de connexion suffisamment faible et des caractéristiques de transmission suffisamment bonnes. Un film de blindage électromagnétique selon la présente invention est caractérisé en ce qu'il est composé d'une couche de protection, d'une couche de blindage qui est superposée sur la couche de protection, et une couche adhésive isolante qui est superposée sur la couche de blindage, et est également caractérisé en ce que : la couche de blindage est pourvue d'une bosse conductrice sur le côté couche adhésive isolante ; la couche adhésive isolante a une première surface de couche adhésive isolante sur le côté couche de blindage et une seconde surface de couche adhésive isolante sur le côté inverse de la première surface de couche adhésive isolante ; et la rugosité de surface (Ra) de la seconde surface de couche adhésive isolante est de 0,5 à 2,0 µm.
PCT/JP2019/042153 2018-10-29 2019-10-28 Film de blindage électromagnétique, procédé de production de carte de circuit imprimé blindée, et carte de circuit imprimé blindée WO2020090726A1 (fr)

Priority Applications (3)

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CN201980057301.9A CN112586103A (zh) 2018-10-29 2019-10-28 电磁波屏蔽膜、屏蔽印制线路板的制造方法及屏蔽印制线路板
KR1020217015067A KR102530878B1 (ko) 2018-10-29 2019-10-28 전자파 차폐 필름, 차폐 프린트 배선판의 제조 방법, 및 차폐 프린트 배선판
JP2020553884A JP7244534B2 (ja) 2018-10-29 2019-10-28 電磁波シールドフィルム、シールドプリント配線板の製造方法、及び、シールドプリント配線板

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JP2018202932 2018-10-29

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KR (1) KR102530878B1 (fr)
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TW202017463A (zh) 2020-05-01
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KR102530878B1 (ko) 2023-05-09
JP7244534B2 (ja) 2023-03-22
CN112586103A (zh) 2021-03-30
JPWO2020090726A1 (ja) 2021-11-11

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