WO2018147424A1 - プリント配線板 - Google Patents
プリント配線板 Download PDFInfo
- Publication number
- WO2018147424A1 WO2018147424A1 PCT/JP2018/004658 JP2018004658W WO2018147424A1 WO 2018147424 A1 WO2018147424 A1 WO 2018147424A1 JP 2018004658 W JP2018004658 W JP 2018004658W WO 2018147424 A1 WO2018147424 A1 WO 2018147424A1
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- WO
- WIPO (PCT)
- Prior art keywords
- metal layer
- point metal
- melting point
- wiring board
- printed wiring
- Prior art date
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Classifications
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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
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0263—High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board
- H05K1/0265—High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board characterized by the lay-out of or details of the printed conductors, e.g. reinforced conductors, redundant conductors, conductors having different cross-sections
-
- 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
- H05K1/0215—Grounding of printed circuits by connection to external grounding means
-
- 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
- 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
- H05K9/0084—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
-
- 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
-
- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/07—Electric details
- H05K2201/0776—Resistance and impedance
-
- 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
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
- H05K2201/10227—Other objects, e.g. metallic pieces
- H05K2201/10371—Shields or metal cases
-
- 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
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
- H05K3/323—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives by applying an anisotropic conductive adhesive layer over an array of pads
Definitions
- the present invention relates to a printed wiring board.
- the peel value (force required for peeling) of the reinforcing member with respect to the conductive adhesive is lowered in a high temperature and high humidity environment.
- the reinforcing member may be peeled off from the conductive adhesive, the adhesive force between the conductive adhesive and the reinforcing member is reduced, and the shielding performance is reduced due to an increase in the electric resistance value.
- the shielding performance is reduced due to an increase in the electric resistance value.
- the present invention has been made to solve the above problems, and an object of the present invention is to provide a printed wiring board in which the electrical resistance value between the ground circuit and the reinforcing member of the printed wiring board is unlikely to increase. is there.
- the printed wiring board of the present invention is formed on a base film in which a printed circuit including a ground circuit is formed on a base film, an adhesive layer formed on the base film, and an adhesive layer.
- First conductive particles in which the first low-melting-point metal layer is formed second conductive particles in which the first low-melting-point metal layer is conductive, and third conductive in which the first low-melting-point metal layer is formed on the conductive core particles
- a second low-melting-point metal layer is formed between the base film and the adhesive layer, or the base film and the adhesive layer.
- a third low melting point metal layer is formed between the adhesive layer and the reinforcing member, or the adhesive layer and the reinforcing member are in direct contact, and the printed wiring board is
- the ground circuit and the reinforcing member include at least one low melting point metal layer selected from the group consisting of a first low melting point metal layer, the second low melting point metal layer, and the third low melting point metal layer. Is electrically connected via at least one low melting point metal layer selected from the group consisting of the first low melting point metal layer, the second low melting point metal layer, and the third low melting point metal layer. It is characterized by being.
- the printed wiring board of the present invention includes at least one low melting point metal layer selected from the group consisting of a first low melting point metal layer, a second low melting point metal layer, and a third low melting point metal layer, and a ground circuit. And the reinforcing member electrically through at least one low melting point metal layer selected from the group consisting of the first low melting point metal layer, the second low melting point metal layer, and the third low melting point metal layer. It is connected.
- the low melting point metal layer is thus formed, the adhesion between the conductive particles, the adhesion between the base film and the adhesive layer, and the adhesion between the adhesive layer and the reinforcing member are improved. be able to. Therefore, it is possible to suppress an increase in the electric resistance value due to the contact displacement.
- the average particle size of the conductive particles is preferably 1 to 200 ⁇ m.
- the average particle diameter of the conductive particles is less than 1 ⁇ m, the conductive particles are small, so that it is difficult to uniformly disperse them in the adhesive layer.
- the average particle diameter of the conductive particles exceeds 200 ⁇ m, the specific surface area becomes small and the conductive particles are difficult to contact each other. As a result, the electrical resistance value of the adhesive layer is likely to increase.
- the first low melting point metal layer is made of a metal having a melting point of 300 ° C. or lower.
- the first low-melting-point metal layer is formed of a metal having a melting point of 300 ° C. or lower, the first low-melting-point metal layer is easily softened, and the adhesion between the first conductive particles is preferably improved. it can.
- the first low melting point metal layer is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the first low melting point metal layer is 0.1 to 50 ⁇ m.
- the thickness of the first low melting point metal layer is less than 0.1 ⁇ m, the amount of the metal constituting the first low melting point metal layer is small, so that the adhesion between the first conductive particles is difficult to improve.
- the thickness of the first low-melting point metal layer exceeds 50 ⁇ m, the first low-melting point metal layer is thick, so that the shape of the first low-melting point metal layer is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the first low melting point metal layer contains a flux.
- the first low-melting-point metal layer contains the flux, when the metal constituting the first low-melting-point metal layer is softened, the adhesion between the conductive particles is easily improved.
- the second low melting point metal layer is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the second low-melting-point metal layer is formed of a metal having a melting point of 300 ° C. or lower, the second low-melting-point metal layer is easily softened, and the adhesion between the base film and the adhesive layer is preferably improved. Can do.
- the second low melting point metal layer is heated once and softened.
- the second low melting point metal layer is formed of a metal having a melting point exceeding 300 ° C., the heating temperature becomes high. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the second low melting point metal layer is 0.1 to 50 ⁇ m. If the thickness of the second low-melting-point metal layer is less than 0.1 ⁇ m, the amount of metal constituting the second low-melting-point metal layer is small, so that the adhesion between the base film and the adhesive layer is difficult to improve. . When the thickness of the second low-melting point metal layer exceeds 50 ⁇ m, the second low-melting point metal layer is thick, so that the shape of the second low-melting point metal layer is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the second low melting point metal layer contains a flux.
- the second low-melting-point metal layer contains a flux, when the metal constituting the second low-melting-point metal layer is softened, the adhesion between the base film and the adhesive layer is easily improved.
- the third low melting point metal layer is formed of a metal having a melting point of 300 ° C. or less.
- the third low melting point metal layer is easily softened, and the adhesiveness between the adhesive layer and the reinforcing member is preferably improved. Can do.
- the third low melting point metal layer is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the third low melting point metal layer is preferably 0.1 to 50 ⁇ m. If the thickness of the third low-melting-point metal layer is less than 0.1 ⁇ m, the amount of metal constituting the third low-melting-point metal layer is small, so that the adhesion between the adhesive layer and the reinforcing member is difficult to improve. . When the thickness of the third low-melting point metal layer exceeds 50 ⁇ m, the third low-melting point metal layer is thick, so that the shape of the third low-melting point metal layer is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the third low melting point metal layer contains a flux.
- the third low-melting-point metal layer contains the flux, when the metal constituting the third low-melting-point metal layer is softened, the adhesion between the adhesive layer and the reinforcing member is easily improved.
- the conductive particles are first conductive particles in which a first low-melting-point metal layer is formed on core particles that are not conductive, second conductive particles that themselves have conductivity, and , At least one selected from the group consisting of third conductive particles in which a first low melting point metal layer is formed on conductive core particles.
- a second low melting point metal layer is formed between the base film and the adhesive layer, or the base film and the adhesive layer are in direct contact with each other.
- a third low melting point metal layer is formed between the adhesive layer and the reinforcing member, or the adhesive layer and the reinforcing member are in direct contact with each other. is doing.
- the printed wiring board according to the present invention includes at least one low melting point metal layer selected from the group consisting of the first low melting point metal layer, the second low melting point metal layer, and the third low melting point metal layer.
- the ground circuit and the reinforcing member are at least one low melting point metal selected from the group consisting of a first low melting point metal layer, a second low melting point metal layer, and a third low melting point metal layer. It is electrically connected through the layers. Accordingly, the low melting point metal layer can improve the adhesion between the conductive particles, the adhesion between the base film and the adhesive layer, and the adhesion between the adhesive layer and the reinforcing member. Therefore, it is possible to suppress an increase in the electric resistance value due to the contact displacement.
- FIG. 1 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 2 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 3 is a sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 4 is a sectional view schematically showing an example of the printed wiring board of the present invention.
- FIGS. 5A and 5B are diagrams schematically showing an example of the conductive particle preparation step in the method for producing a printed wiring board of the present invention.
- FIG. 6 is a diagram schematically showing an example of the adhesive layer paste manufacturing step in the method for manufacturing a printed wiring board of the present invention.
- FIG. 7A and 7B are diagrams schematically showing an example of an adhesive layer forming step in the method for producing a printed wiring board of the present invention.
- FIG. 8 is a diagram schematically showing an example of a reinforcing member installation step in the method for manufacturing a printed wiring board according to the present invention.
- FIG. 9 is a diagram schematically showing an example of a heating step in the method for producing a printed wiring board of the present invention.
- FIG. 10 is a sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 11 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 12 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 13 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 14 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 15 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 16 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- FIG. 1 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- the printed wiring board 10 is formed on a base film 60 in which a printed circuit 62 including a ground circuit 62 a and an insulating film 63 are sequentially provided on a base film 61, and the base film 60.
- the printed wiring board includes an adhesive layer 70 and a conductive reinforcing member 80 formed on the adhesive layer 70.
- the adhesive layer 70 includes conductive particles 71 and an adhesive resin 72.
- the conductive particles 71 are non-conductive core particles 73 are the first conductive particles 71 a on which the first low melting point metal layer 91 is formed.
- the first conductive particles 71 a are connected to each other through the first low melting point metal layer 91. Therefore, the ground circuit 62a and the reinforcing member 80 are electrically connected via the first low melting point metal layer 91 of the first conductive particles 71a.
- the materials of the base film 61 and the insulating film 63 constituting the base film 60 are not particularly limited, but are preferably made of engineering plastic.
- engineering plastics include resins such as polyethylene terephthalate, polypropylene, crosslinked polyethylene, polyester, polybenzimidazole, polyimide, polyimide amide, polyether imide, and polyphenylene sulfide.
- a polyphenylene sulfide film is desirable when flame retardancy is required, and a polyimide film is desirable when heat resistance is required.
- the thickness of the base film 61 is desirably 10 to 40 ⁇ m
- the thickness of the insulating film 63 is desirably 10 to 30 ⁇ m.
- the insulating film 63 has a hole 63a for exposing a part of the ground circuit 62a.
- the method for forming the hole 63a is not particularly limited, and a conventional method such as laser processing can be employed.
- the thickness of the adhesive layer 70 is not particularly limited, and is desirably determined according to the use of the printed wiring board 10.
- the thickness of the adhesive layer 70 may be, for example, 5 to 50 ⁇ m.
- the adhesive layer 70 of the printed wiring board 10 includes first conductive particles 71 a and an adhesive resin 72.
- the adhesive resin 72 is not particularly limited, but is preferably an acrylic resin, an epoxy resin, a silicon resin, a thermoplastic elastomer resin, a rubber resin, a polyester resin, a urethane resin, or the like.
- the adhesive resin 72 contains tackifiers such as fatty acid hydrocarbon resins, C5 / C9 mixed resins, rosin, rosin derivatives, terpene resins, aromatic hydrocarbon resins, and heat-reactive resins. Also good. When these tackifiers are included, the tackiness of the adhesive resin 72 can be improved.
- the first conductive particle 71a includes the core particle 73 having no conductivity.
- the core particle 73 include an epoxy resin, a phenol resin, a urethane resin, a melamine resin, an alkyd resin, an acrylic resin, A thermosetting resin such as a styrene resin can be used.
- the average particle diameter of the first conductive particles 71a is preferably 1 to 200 ⁇ m.
- the average particle diameter of the first conductive particles 71 a is less than 1 ⁇ m, the first conductive particles 71 a are small, and thus it is difficult to uniformly disperse the adhesive layer 70.
- the average particle diameter of the first conductive particles 71a exceeds 200 ⁇ m, the specific surface area becomes small and the first conductive particles 71a are difficult to contact each other. As a result, the electrical resistance value of the adhesive layer 70 is likely to increase.
- the first low melting point metal layer 91 is formed on the surface of the core particle 73. Therefore, the adhesive layer 70 including the first conductive particles 71a made of the core particles 73 having the first low melting point metal layer 91 formed on the surface can function as a conductive adhesive layer. Further, the low melting point metal layer 91 can improve the adhesion between the first conductive particles 71a. Accordingly, it is possible to suppress an increase in the electrical resistance value due to the contact shift between the first conductive particles 71a.
- the first low melting point metal layer 91 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the first low melting point metal layer 91 is easily softened, and the adhesion between the first conductive particles 71a is preferably improved. Can be made.
- the first low melting point metal layer 91 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board 10 is easily damaged by heat.
- the first low melting point metal layer 91 is not particularly limited, but preferably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the first low melting point metal layer 91.
- the thickness of the first low melting point metal layer 91 is preferably 0.1 to 50 ⁇ m.
- the thickness of the first low melting point metal layer 91 is less than 0.1 ⁇ m, the amount of the metal constituting the first low melting point metal layer 91 is small, so that the adhesion between the first conductive particles 71a is improved. It becomes difficult.
- the thickness of the first low melting point metal layer 91 exceeds 50 ⁇ m, since the first low melting point metal layer 91 is thick, the shape of the first low melting point metal layer 91 is likely to change greatly during heating. Therefore, the shape of the printed wiring board 10 is likely to be distorted.
- the content of the first low melting point metal layer 91 in the first conductive particles 71a is preferably 1 wt% or more, more preferably 5 to 50 wt%, and further preferably 10 to 30 wt%. desirable. If the content of the first low-melting-point metal layer 91 is less than 1 wt%, the amount of metal constituting the first low-melting-point metal layer 91 is small, so that the adhesion between the first conductive particles 71a is difficult to improve. . If the content of the first low melting point metal layer 91 exceeds 50 wt%, the first low melting point metal layer 91 is thick, and thus the shape of the first low melting point metal layer 91 is likely to change greatly during heating. Therefore, the shape of the printed wiring board 10 is likely to be distorted.
- the first low melting point metal layer 91 preferably includes a flux.
- the first low-melting-point metal layer 91 includes a flux, when the metal constituting the first low-melting-point metal layer 91 is softened, the adhesion between the first conductive particles 71a is easily improved.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the weight ratio between the first conductive particles 71a and the adhesive resin 72 is the above ratio, the first conductive particles 71a can easily come into contact with each other. Accordingly, it is possible to suppress an increase in the electrical resistance value due to the contact shift between the first conductive particles 71a.
- the material of the reinforcing member 80 is not particularly limited, but is desirably stainless steel, nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, or an alloy thereof. These materials have strength and conductivity suitable as reinforcing members.
- a nickel layer or a noble metal layer may be formed on the surface of the reinforcing member 80.
- the glossiness of the nickel layer is desirably 500 or less, and more desirably 460 or less.
- the glossiness of the nickel layer is 500 or less, the surface area of the bonding surface between the reinforcing member 80 and the adhesive layer 70 can be increased, and the adhesive force can be kept high. It is further desirable that the nickel layer does not contain a gloss additive and is matte.
- the second low melting point metal layer may be formed between the base film and the adhesive layer, and the third low melting point metal layer is interposed between the adhesive layer and the reinforcing member. May be formed. Such an embodiment is illustrated and described. 2 to 4 are sectional views schematically showing an example of the printed wiring board of the present invention.
- the second low melting point metal layer 92 is formed between the base film 60 and the adhesive layer 70, and the adhesive layer 70 and the reinforcing member 80 are in direct contact with each other. is doing.
- the base film 60 and the adhesive layer 70 are in direct contact, and a third low melting point metal layer 93 is formed between the adhesive layer 70 and the reinforcing member 80. Has been.
- the second low melting point metal layer 92 is formed between the base film 60 and the adhesive layer 70, and the adhesive layer 70 and the reinforcing member 80 are interposed between them.
- a third low melting point metal layer 93 is formed.
- the second low melting point metal layer 92 may cover the entire surface of the base film 60 as shown in FIGS. 3 and 5, or may cover only a part of the ground circuit 62a.
- the third low melting point metal layer 93 may cover the entire surface of the reinforcing member 80 as shown in FIGS. 4 and 5, or may cover only a part of the reinforcing member 80.
- the second low melting point metal layer 92 desirably has the following characteristics.
- the second low melting point metal layer 92 is not particularly limited, but desirably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the second low melting point metal layer 92.
- the second low melting point metal layer 92 is preferably made of a metal having a melting point of 300 ° C. or lower.
- the second low melting point metal layer 92 is formed of a metal having a melting point of 300 ° C. or less, the second low melting point metal layer 92 is easily softened, and the adhesion between the base film 60 and the adhesive layer 70 is preferable. Can be improved.
- the second low melting point metal layer 92 is heated once and softened.
- the second low melting point metal layer 92 is formed of a metal having a melting point exceeding 300 ° C., the heating temperature becomes high. Therefore, the printed wiring board of the present invention is easily damaged by heat.
- the thickness of the second low melting point metal layer 92 is preferably 0.1 to 50 ⁇ m. If the thickness of the second low melting point metal layer 92 is less than 0.1 ⁇ m, the amount of the metal constituting the second low melting point metal layer 92 is small, so that the adhesion between the base film 60 and the adhesive layer 70 is improved. It becomes difficult to improve. If the thickness of the second low-melting-point metal layer 92 exceeds 50 ⁇ m, the second low-melting-point metal layer 92 is thick, so that the shape of the second low-melting-point metal layer 92 is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the second low melting point metal layer 92 desirably contains a flux.
- the adhesion between the base film 60 and the adhesive layer 70 is easily improved when the metal constituting the second low melting point metal layer 92 is softened.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the 3rd low melting metal layer 93 when the printed wiring board of this invention is equipped with the 3rd low melting metal layer 93, it is desirable for the 3rd low melting metal layer 93 to have the following characteristics.
- the third low-melting-point metal layer 93 is not particularly limited, but desirably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the second low melting point metal layer 93.
- the third low melting point metal layer 93 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the third low melting point metal layer 93 is easily softened, and the adhesiveness between the adhesive layer 70 and the reinforcing member 80 is preferable. Can be improved.
- the third low melting point metal layer 93 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the third low melting point metal layer 93 is preferably 0.1 to 50 ⁇ m.
- the thickness of the third low melting point metal layer 93 is less than 0.1 ⁇ m, the amount of the metal constituting the third low melting point metal layer 93 is small, so that the adhesion between the adhesive layer 70 and the reinforcing member 80 is improved. It becomes difficult to improve.
- the thickness of the third low melting point metal layer 93 exceeds 50 ⁇ m, the third low melting point metal layer 93 is thick, and thus the shape of the third low melting point metal layer 93 is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the third low melting point metal layer 93 desirably contains a flux.
- the third low-melting-point metal layer 93 includes a flux, when the metal constituting the third low-melting-point metal layer 93 is softened, the adhesion between the adhesive layer 70 and the reinforcing member 80 is easily improved.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- FIGS. 5A and 5B are diagrams schematically showing an example of the conductive particle preparation step in the method for producing a printed wiring board of the present invention.
- FIG. 6 is a diagram schematically showing an example of the adhesive layer paste manufacturing step in the method for manufacturing a printed wiring board of the present invention.
- 7A and 7B are diagrams schematically showing an example of an adhesive layer forming step in the method for producing a printed wiring board of the present invention.
- FIG. 8 is a diagram schematically showing an example of a reinforcing member installation step in the method for manufacturing a printed wiring board according to the present invention.
- FIG. 9 is a diagram schematically showing an example of a heating step in the method for producing a printed wiring board of the present invention.
- the manufacturing method of the printed wiring board 10 includes (1) conductive particle preparation step, (2) adhesive layer paste preparation step, (3) adhesive layer formation step, and (4) reinforcing member installation step. And (5) a method including a heating step.
- thermosetting resins such as an epoxy resin, a phenol resin, a urethane resin, a melamine resin, an alkyd resin, an acrylic resin, a styrene resin, can be used.
- a first low-melting-point metal layer 91 is formed on the surface of the core particle 73 having no conductivity.
- a method of forming the first low melting point metal layer 91 on the surface of the core particle 73 having no conductivity for example, a method such as electroless plating, electrolytic plating, or vacuum deposition can be employed. Since the desirable metals for forming the first low melting point metal layer 91 are as described above, description thereof is omitted here.
- the 1st electroconductive particle 71a which is the core particle 73 in which the 1st low melting metal layer 91 was formed in the surface can be prepared.
- the first conductive particles 71 a and the adhesive resin 72 are mixed to produce an adhesive layer paste 75.
- the weight ratio between the first conductive particles 71a and the adhesive resin 72 is the above ratio, the first conductive particles 71a can easily come into contact with each other. Accordingly, it is possible to suppress an increase in the electrical resistance value due to the contact shift between the first conductive particles 71a.
- a base film 60 is prepared in which a printed circuit 62 including a ground circuit 62a and an insulating film 63 are sequentially provided on the base film 61. Then, a hole 63a is formed to expose a part of the ground circuit 62a.
- the method for forming the hole 63a is not particularly limited, and a conventional method such as laser processing can be employed.
- an adhesive layer paste 75 is applied on the insulating layer 63 of the base film 60 to form an adhesive layer 70 as shown in FIG. 7B. To do. At this time, the hole 63 a of the insulating layer 63 is filled with the adhesive layer 70, and the ground circuit 62 a and the adhesive layer 70 come into contact with each other.
- a reinforcing member 80 is installed on the adhesive layer 70. It is desirable to adjust the size and position of the reinforcing member 80 to be installed according to the use of the printed wiring board to be manufactured. In this manner, a printed wiring board including a base film, an adhesive layer formed on the base film, and a conductive reinforcing member formed on the adhesive layer can be produced.
- the heating temperature is not particularly limited as long as it is a temperature at which the first low-melting point metal layer is softened, but it is preferably 100 to 300 ° C.
- a solder reflow process is performed.
- the low melting point metal layer may be softened by heat during reflow in this reflow step. In this case, the heating process and the component mounting are performed simultaneously.
- the printed wiring board 10 can be manufactured through the above steps.
- the second low melting point metal layer 92 is formed between the base film 60 and the adhesive layer 70, as in the printed wiring board 11 to the printed wiring board 13 shown in FIGS.
- the base film 60 is formed when performing the above (3) adhesive layer forming step and (4) reinforcing member installing step.
- the second low melting point metal layer 92 may be formed thereon, or the third low melting point metal layer 93 may be formed on the adhesive layer 70.
- a plating method can be adopted.
- the printed wiring board of the present invention may be provided with an electromagnetic wave shielding film for shielding electromagnetic waves.
- FIG. 10 is a sectional view schematically showing an example of the printed wiring board of the present invention.
- the printed wiring board 110 is formed on a base film 160 in which a printed circuit 162 including a ground circuit 162 a and an insulating film 163 are sequentially provided on a base film 161, and the base film 160.
- the printed wiring board includes an adhesive layer 170 and a conductive reinforcing member 180 formed on the adhesive layer 170.
- the adhesive layer 170 includes conductive particles 171 and an adhesive resin 172, and the conductive particles 171 are second conductive particles 171b that themselves have conductivity.
- a second low melting point metal layer 192 is formed between the base film 160 and the adhesive layer 170. Therefore, the ground circuit 162a and the reinforcing member 180 are electrically connected via the second low melting point metal layer 192.
- the adhesive layer 170 of the printed wiring board 110 will be described.
- the thickness of the adhesive layer 170 is not particularly limited, and is desirably determined according to the use of the printed wiring board 110.
- the thickness of the adhesive layer 170 may be, for example, 5 to 50 ⁇ m.
- the adhesive layer 170 of the printed wiring board 110 includes second conductive particles 171b and an adhesive resin 172.
- the adhesive resin 172 is not particularly limited, but is preferably an acrylic resin, an epoxy resin, a silicon resin, a thermoplastic elastomer resin, a rubber resin, a polyester resin, a urethane resin, or the like.
- the adhesive resin 172 contains tackifiers such as fatty acid hydrocarbon resins, C5 / C9 mixed resins, rosin, rosin derivatives, terpene resins, aromatic hydrocarbon resins, and heat-reactive resins. Also good. When these tackifiers are included, the tackiness of the adhesive resin 172 can be improved.
- the adhesive layer 170 can function as a conductive adhesive layer without providing a low melting point metal layer or the like on the surface of the second conductive particles 171b.
- the second conductive particles 171b include at least one selected from the group consisting of copper, aluminum, silver, nickel, nickel-coated copper, nickel-coated silver, silver-coated copper, and silver-coated resin. Is desirable.
- the average particle diameter of the second conductive particles 171b is preferably 1 to 200 ⁇ m.
- the average particle diameter of the second conductive particles 171b is less than 1 ⁇ m, the second conductive particles 171b are small, so that it is difficult to uniformly disperse in the adhesive layer 170.
- the average particle diameter of the second conductive particles 171b exceeds 200 ⁇ m, the specific surface area becomes small, and the second conductive particles 171b hardly come into contact with each other. As a result, the electrical resistance value of the adhesive layer 170 is likely to increase.
- the second low melting point metal layer 192 of the printed wiring board 110 will be described.
- a second low melting point metal layer 192 is formed between the base film 160 and the adhesive layer 170. Therefore, the adhesion between the base film 160 and the adhesive layer 170 can be improved. Accordingly, it is possible to suppress an increase in the electrical resistance value due to a shift in contact between the base film 160 and the adhesive layer 170.
- the second low melting point metal layer 192 may cover the entire surface of the base film 160 as shown in FIG. 10, or may cover only a part of the ground circuit 162a.
- the second low melting point metal layer 192 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the second low melting point metal layer 192 is easily softened, and the adhesion between the base film 160 and the adhesive layer 170 is preferably improved. Can be improved.
- the second low melting point metal layer 192 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board 110 is easily damaged by heat.
- the second low-melting-point metal layer 192 is not particularly limited, but desirably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the second low melting point metal layer 192.
- the thickness of the second low melting point metal layer 192 is preferably 0.1 to 50 ⁇ m. If the thickness of the second low-melting-point metal layer 192 is less than 0.1 ⁇ m, the amount of metal constituting the second low-melting-point metal layer 192 is small, so that the adhesion between the base film 160 and the adhesive layer 170 is reduced. It becomes difficult to improve. If the thickness of the second low-melting-point metal layer 192 exceeds 50 ⁇ m, the second low-melting-point metal layer 192 is thick, so that the shape of the second low-melting-point metal layer 192 is easily changed during heating. Therefore, the shape of the printed wiring board 110 is likely to be distorted.
- the second low melting point metal layer 192 includes a flux.
- the second low-melting-point metal layer 192 contains a flux, when the metal constituting the second low-melting-point metal layer 192 is softened, the adhesion between the base film 160 and the adhesive layer 170 is easily improved.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the weight ratio between the second conductive particles 171b and the adhesive resin 172 is the above ratio, the second conductive particles 171b can easily come into contact with each other. Accordingly, it is possible to suppress an increase in the electric resistance value due to the contact shift between the second conductive particles 171b.
- desirable configurations of the base film 160 and the reinforcing member 180 are the same as desirable configurations of the base film 60 and the reinforcing member 80 of the printed wiring board 10.
- the conductive particles 171 are second conductive particles 171 b that are conductive, and the base film 160 and the adhesive layer 170 are in direct contact with each other.
- a third low melting point metal layer 193 is formed between the agent layer 170 and the reinforcing member 180. Note that the third low melting point metal layer 193 may cover the entire surface of the reinforcing member 180 as shown in FIG. 11 or may cover only a part of the reinforcing member 180.
- the conductive particles 171 are second conductive particles 171 b having conductivity, and the second low melting point metal is interposed between the base film 160 and the adhesive layer 170.
- a layer 192 is formed, and a third low melting point metal layer 193 is formed between the adhesive layer 170 and the reinforcing member 180.
- the printed wiring board of this invention is provided with the 3rd low melting metal layer 193, it is desirable for the 3rd low melting metal layer 193 to have the following characteristics.
- the third low melting point metal layer 193 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the third low melting point metal layer 193 is easily softened, and the adhesiveness between the adhesive layer 170 and the reinforcing member 180 is preferable. Can be improved.
- the third low melting point metal layer 193 is heated once and softened.
- the heating temperature is increased. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the third low melting point metal layer 193 is preferably 0.1 to 50 ⁇ m. If the thickness of the third low-melting-point metal layer 193 is less than 0.1 ⁇ m, the amount of metal constituting the third low-melting-point metal layer 193 is small, so that the adhesion between the adhesive layer 170 and the reinforcing member 180 is improved. It becomes difficult to improve. If the thickness of the third low-melting-point metal layer 193 exceeds 50 ⁇ m, the third low-melting-point metal layer 193 is thick, so that the shape of the third low-melting-point metal layer 193 is easily changed during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the third low melting point metal layer 193 preferably contains a flux.
- the third low-melting-point metal layer 193 includes a flux, when the metal constituting the third low-melting-point metal layer 193 is softened, the adhesion between the adhesive layer 170 and the reinforcing member 180 is easily improved.
- the second conductive material is used instead of the first conductive particle.
- the second low-melting-point metal layer is formed on the base film when performing the “(3) adhesive layer forming step” or the “(4) reinforcing member installation step”
- a third low melting point metal layer may be formed on the layer.
- a method of forming these low melting point metal layers for example, a plating method can be adopted.
- FIG. 13 is a cross-sectional view schematically showing an example of the printed wiring board of the present invention.
- the printed wiring board 210 is formed on a base film 260 in which a printed circuit 262 including a ground circuit 262 a and an insulating film 263 are sequentially provided on a base film 261, and the base film 260.
- the printed wiring board includes an adhesive layer 270 and a conductive reinforcing member 280 formed on the adhesive layer 270.
- the adhesive layer 270 includes conductive particles 271 and an adhesive resin 272.
- the conductive particles 271 include a first low melting point metal layer 291 formed on the core particles 273 having conductivity. 3 conductive particles 271c.
- the third conductive particles 271c are connected to each other through the first low melting point metal layer 291. Therefore, the ground circuit 262a and the reinforcing member 280 are electrically connected via the first low melting point metal layer 291 of the third conductive particles 271c.
- the adhesive layer 270 of the printed wiring board 210 will be described.
- the thickness of the adhesive layer 270 is not particularly limited, and is desirably determined according to the use of the printed wiring board 210.
- the thickness of the adhesive layer 270 may be, for example, 5 to 50 ⁇ m.
- the adhesive layer 270 of the printed wiring board 210 includes third conductive particles 271c and an adhesive resin 272.
- the adhesive resin 272 is not particularly limited, but is preferably an acrylic resin, an epoxy resin, a silicon resin, a thermoplastic elastomer resin, a rubber resin, a polyester resin, a urethane resin, or the like.
- the adhesive resin 272 contains a tackifier such as a fatty acid hydrocarbon resin, a C5 / C9 mixed resin, a rosin, a rosin derivative, a terpene resin, an aromatic hydrocarbon resin, and a thermally reactive resin. Also good. When these tackifiers are contained, the tackiness of the adhesive resin 272 can be improved.
- a first low melting point metal layer 291 is formed on the surface of the conductive core particles 273. Therefore, the adhesive layer 270 including the third conductive particles 271c made of the core particles 273 having the first low melting point metal layer 291 formed on the surface can function as a conductive adhesive layer.
- the core particle 273 since the core particle 273 has conductivity, the core particle 273 is exposed, and even if the third conductive particles 271c come into contact with each other at that location, a current flows between the third conductive particles 271c. . Therefore, even if the core particles 273 are exposed due to friction or the like, conductivity can be ensured.
- the third conductive particles 271c include at least one selected from the group consisting of copper, aluminum, silver, nickel, nickel-coated copper, nickel-coated silver, silver-coated copper, and silver-coated resin. Is desirable.
- the average particle diameter of the third conductive particles 271c is preferably 1 to 200 ⁇ m.
- the average particle diameter of the third conductive particles 271c is less than 1 ⁇ m, the third conductive particles 271c are small, so that it is difficult to uniformly disperse in the adhesive layer 270.
- the average particle diameter of the third conductive particles 271c exceeds 200 ⁇ m, the specific surface area becomes small, and the third conductive particles 271c are difficult to contact each other. As a result, the electrical resistance value of the adhesive layer 270 is likely to increase.
- the first low melting point metal layer 291 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the first low melting point metal layer 291 is easily softened, and the adhesion between the third conductive particles 271c is preferably improved. Can be made.
- the first low melting point metal layer 291 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board 210 is easily damaged by heat.
- the first low-melting-point metal layer 291 is not particularly limited, but preferably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the first low melting point metal layer 291.
- the first low melting point metal layer 291 When the first low melting point metal layer 291 is made of tin, the first low melting point metal layer 291 and the metal constituting the core particle 273 may form an alloy. Therefore, it is desirable that a nickel layer be formed between the core particle 273 and the first low melting point metal layer 291. When a nickel layer is formed between the core particle 273 and the first low melting point metal layer 291, it is possible to prevent such an alloy from being formed. As a result, the third conductive particles 271c can be efficiently adhered to each other. Therefore, the amount of tin used for the first low melting point metal layer 291 can be reduced.
- the thickness of the first low melting point metal layer 291 is preferably 0.1 to 50 ⁇ m. If the thickness of the first low melting point metal layer 291 is less than 0.1 ⁇ m, the amount of the metal constituting the first low melting point metal layer 291 is small, so that the adhesion between the third conductive particles 271c is improved. It becomes difficult. When the thickness of the first low melting point metal layer 291 exceeds 50 ⁇ m, the first low melting point metal layer 291 is thick, so that the shape of the first low melting point metal layer 291 is likely to change greatly during heating. For this reason, the shape of the printed wiring board 210 is likely to be distorted.
- the content of the first low melting point metal layer 291 in the first conductive particles 271a is desirably 1 wt% or more, more desirably 5 to 50 wt%, and desirably 10 to 30 wt%. More desirable. If the content of the first low melting point metal layer 291 is less than 1 wt%, the amount of metal constituting the first low melting point metal layer 291 is small, and therefore the adhesion between the first conductive particles 271a is difficult to improve. . If the content of the first low melting point metal layer 291 exceeds 50 wt%, the first low melting point metal layer 291 is thick, and thus the shape of the first low melting point metal layer 291 is likely to change greatly during heating. For this reason, the shape of the printed wiring board 210 is likely to be distorted.
- the first low melting point metal layer 291 preferably includes a flux.
- the first low-melting-point metal layer 291 includes a flux, when the metal constituting the first low-melting-point metal layer 291 is softened, the adhesion between the third conductive particles 271c is easily improved.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the third conductive particles 271a can easily come into contact with each other. Accordingly, it is possible to suppress an increase in the electrical resistance value due to the displacement of the contact between the third conductive particles 271a.
- desirable configurations and the like of the base film 260 and the reinforcing member 280 are the same as the desirable configurations of the base film 60 and the reinforcing member 80 of the printed wiring board 10.
- the second low melting point metal layer may be formed between the base film and the adhesive layer, and the third low melting point metal layer is interposed between the adhesive layer and the reinforcing member. May be formed. Such an embodiment is illustrated and described. Such an embodiment is illustrated and described. 14 to 16 are cross-sectional views schematically showing an example of the printed wiring board of the present invention.
- the first low melting point metal layer 291 is formed around the third conductive particles 271c, and the second low melting point metal layer 291 is interposed between the base film 260 and the adhesive layer 270.
- a melting point metal layer 292 is formed, and the adhesive layer 270 and the reinforcing member 280 are in direct contact with each other.
- the first low melting point metal layer 291 is formed around the third conductive particles 271c, and the base film 260 and the adhesive layer 270 are in direct contact with each other.
- a third low melting point metal layer 293 is formed between the adhesive layer 270 and the reinforcing member 280.
- the first low melting point metal layer 291 is formed around the third conductive particles 271c, and between the base film 260 and the adhesive layer 270.
- a second low melting point metal layer 292 is formed, and a third low melting point metal layer 293 is formed between the adhesive layer 270 and the reinforcing member 280.
- the second low melting point metal layer 292 may cover the entire surface of the base film 260 as shown in FIGS. 14 and 16, or may cover only a part of the ground circuit 262a. Further, the third low melting point metal layer 293 may cover the entire surface of the reinforcing member 280 as shown in FIGS. 15 and 16, or may cover only a part of the reinforcing member 280.
- the second low-melting point metal layer 292 desirably has the following characteristics.
- the second low-melting-point metal layer 292 is not particularly limited, but preferably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the second low melting point metal layer 292.
- the second low melting point metal layer 292 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the second low melting point metal layer 292 is easily softened, and the adhesion between the base film 260 and the adhesive layer 270 is preferable. Can be improved.
- the second low melting point metal layer 292 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board of the present invention is easily damaged by heat.
- the thickness of the second low melting point metal layer 292 is preferably 0.1 to 50 ⁇ m. If the thickness of the second low melting point metal layer 292 is less than 0.1 ⁇ m, the amount of the metal constituting the second low melting point metal layer 292 is small, so that the adhesion between the base film 260 and the adhesive layer 270 is improved. It becomes difficult to improve. If the thickness of the second low-melting-point metal layer 292 exceeds 50 ⁇ m, the second low-melting-point metal layer 292 is thick, so that the shape of the second low-melting-point metal layer 292 is likely to change greatly during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the second low melting point metal layer 292 desirably contains a flux.
- the adhesion between the base film 260 and the adhesive layer 270 is easily improved when the metal constituting the second low-melting-point metal layer 292 is softened.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the printed wiring board of this invention is equipped with the 3rd low melting metal layer 293, it is desirable for the 3rd low melting metal layer 293 to have the following characteristics.
- the third low-melting-point metal layer 293 is not particularly limited, but desirably includes at least one selected from the group consisting of indium, tin, lead, and bismuth. These metals have a melting point and conductivity suitable for forming the third low melting point metal layer 292.
- the third low melting point metal layer 293 is preferably formed of a metal having a melting point of 300 ° C. or lower.
- the third low melting point metal layer 293 is easily softened, and the adhesiveness between the adhesive layer 270 and the reinforcing member 280 is preferable. Can be improved.
- the third low melting point metal layer 293 is heated once and softened.
- the heating temperature becomes high. Therefore, the printed wiring board is easily damaged by heat.
- the thickness of the third low melting point metal layer 293 is preferably 0.1 to 50 ⁇ m. If the thickness of the third low melting point metal layer 293 is less than 0.1 ⁇ m, the amount of the metal constituting the third low melting point metal layer 293 is small, so that the adhesiveness between the adhesive layer 270 and the reinforcing member 280 is It becomes difficult to improve. If the thickness of the third low-melting-point metal layer 293 exceeds 50 ⁇ m, the third low-melting-point metal layer 293 is thick, so that the shape of the third low-melting-point metal layer 293 is easily changed during heating. Therefore, the shape of the printed wiring board is likely to be distorted.
- the third low melting point metal layer 293 preferably includes a flux.
- the third low-melting-point metal layer 293 includes a flux, when the metal constituting the third low-melting-point metal layer 293 is softened, the adhesion between the adhesive layer 270 and the reinforcing member 280 is easily improved.
- the flux is not particularly limited, and known ones such as polyvalent carboxylic acid, lactic acid, citric acid, oleic acid, stearic acid, glutamic acid, benzoic acid, glycerin, rosin can be used.
- the third conductive material is used instead of the first conductive particle.
- the second low-melting-point metal layer is formed on the base film when performing the “(3) adhesive layer forming step” or the “(4) reinforcing member installation step”
- a third low melting point metal layer may be formed on the layer.
- a method of forming these low melting point metal layers for example, a plating method can be adopted.
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Laminated Bodies (AREA)
- Manufacturing Of Printed Wiring (AREA)
- Structure Of Printed Boards (AREA)
- Parts Printed On Printed Circuit Boards (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Conductive Materials (AREA)
Abstract
Description
また、電気抵抗値の上昇の抑制には改善の余地があった。
このように低融点金属層が形成されていると、導電性粒子同士の密着性、基体フィルムと接着剤層との間の密着性、接着剤層と補強部材との間の密着性を向上させることができる。
そのため、接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
導電性粒子の平均粒子径が1μm未満であると、導電性粒子が小さいため、接着剤層に均一に分散させにくくなる。
導電性粒子の平均粒子径が200μmを超えると、比表面積が小さくなり、導電性粒子同士が接触しにくくなる。その結果、接着剤層の電気抵抗値が上昇しやすくなる。
第1低融点金属層が、融点が300℃以下の金属により形成されていると、容易に第1低融点金属層が軟化し、第1導電性粒子同士の密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第1低融点金属層は一度加熱されて軟化することになる。第1低融点金属層が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第1低融点金属層の厚さが、0.1μm未満であると、第1低融点金属層を構成する金属の量が少ないので、第1導電性粒子同士の密着性が向上しにくくなる。
第1低融点金属層の厚さが、50μmを超えると、第1低融点金属層が厚いため、加熱時に第1低融点金属層の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第1低融点金属層がフラックスを含むことにより、第1低融点金属層を構成する金属が軟化する際に、導電性粒子同士の密着性が向上しやすくなる。
第2低融点金属層が、融点が300℃以下の金属により形成されていると、容易に第2低融点金属層が軟化し、基体フィルムと接着剤層との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第2低融点金属層は一度加熱されて軟化することになる。第2低融点金属層が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第2低融点金属層の厚さが、0.1μm未満であると、第2低融点金属層を構成する金属の量が少ないので、基体フィルムと接着剤層との密着性が向上しにくくなる。
第2低融点金属層の厚さが、50μmを超えると、第2低融点金属層が厚いため、加熱時に第2低融点金属層の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第2低融点金属層がフラックスを含むことにより、第2低融点金属層を構成する金属が軟化する際に、基体フィルムと接着剤層との密着性が向上しやすくなる。
第3低融点金属層が、融点が300℃以下の金属により形成されていると、容易に第3低融点金属層が軟化し、接着剤層と補強部材との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第3低融点金属層は一度加熱されて軟化することになる。第3低融点金属層が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第3低融点金属層の厚さが、0.1μm未満であると、第3低融点金属層を構成する金属の量が少ないので、接着剤層と補強部材との密着性が向上しにくくなる。
第3低融点金属層の厚さが、50μmを超えると、第3低融点金属層が厚いため、加熱時に第3低融点金属層の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第3低融点金属層がフラックスを含むことにより、第3低融点金属層を構成する金属が軟化する際に、接着剤層と補強部材との密着性が向上しやすくなる。
また、本発明のプリント配線板では、上記基体フィルムと上記接着剤層との間には第2低融点金属層が形成されている、又は、上記基体フィルムと上記接着剤層とは直接接触している。
また、本発明のプリント配線板では、上記接着剤層と上記補強部材との間には、第3低融点金属層が形成されている、又は、上記接着剤層と上記補強部材とは直接接触している。
そして、本発明のプリント配線板は、上記第1低融点金属層、上記第2低融点金属層、及び、上記第3低融点金属層からなる群から選択される少なくとも1種の低融点金属層を備え、上記グランド回路と、上記補強部材とは、第1低融点金属層、第2低融点金属層、及び、第3低融点金属層からなる群から選択される少なくとも1種の低融点金属層を介して電気的に接続されている。
従って、低融点金属層により、導電性粒子同士の間の密着性、基体フィルムと接着剤層との間の密着性、接着剤層と補強部材との間の密着性を向上させることができる。
そのため、接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
図1は、本発明のプリント配線板の一例を模式的に示す断面図である。
また、接着剤層70は、導電性粒子71と、接着性樹脂72とを含んでいる。
また、そして、導電性粒子71は、導電性を有しないコア粒子73は第1低融点金属層91が形成された第1導電性粒子71aである。
また、第1導電性粒子71a同士は、第1低融点金属層91を介して互いに接続している。
そのため、グランド回路62aと、補強部材80とは、第1導電性粒子71aの第1低融点金属層91を介して電気的に接続されていることになる。
基体フィルム60を構成するベースフィルム61及び絶縁フィルム63の材料は、特に限定されないが、エンジニアリングプラスチックからなることが望ましい。このようなエンジニアリングプラスチックとしては、例えば、ポリエチレンテレフタレート、ポリプロピレン、架橋ポリエチレン、ポリエステル、ポリベンズイミダゾール、ポリイミド、ポリイミドアミド、ポリエーテルイミド、ポリフェニレンサルファイドなどの樹脂が挙げられる。
また、これらのエンジニアリングプラスチックの内、難燃性が要求される場合には、ポリフェニレンサルファイドフィルムが望ましく、耐熱性が要求される場合にはポリイミドフィルムが望ましい。なお、ベースフィルム61の厚みは、10~40μmであることが望ましく、絶縁フィルム63の厚みは、10~30μmであることが望ましい。
穴部63aの形成方法は特に限定されず、レーザー加工等の従来の方法を採用することができる。
接着剤層70の厚さは、特に限定されず、プリント配線板10の用途に合わせて決定することが望ましい。接着剤層70の厚さは、例えば、5~50μmであってもよい。
また、接着性樹脂72には、脂肪酸炭化水素樹脂、C5/C9混合樹脂、ロジン、ロジン誘導体、テルペン樹脂、芳香族系炭化水素樹脂、熱反応性樹脂等の粘着性付与剤が含まれていてもよい。これら粘着性付与剤が含まれていると、接着性樹脂72の粘着性を向上させることができる。
第1導電性粒子71aの平均粒子径が1μm未満であると、第1導電性粒子71aが小さいため、接着剤層70に均一に分散させにくくなる。
第1導電性粒子71aの平均粒子径が200μmを超えると、比表面積が小さくなり、第1導電性粒子71a同士が接触しにくくなる。その結果、接着剤層70の電気抵抗値が上昇しやすくなる。
そのため、第1低融点金属層91が表面に形成されたコア粒子73からなる第1導電性粒子71aを含む接着剤層70は、導電性接着剤層として機能することができる。
また、低融点金属層91は、第1導電性粒子71a同士の間の密着性を向上させることができる。
従って、第1導電性粒子71a同士の接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
第1低融点金属層91が、融点が300℃以下の金属により形成されていると、容易に第1低融点金属層91が軟化し、第1導電性粒子71a同士の密着性を好適に向上させることができる。
なお、プリント配線板10を製造する場合、第1低融点金属層91は一度加熱されて軟化することになる。第1低融点金属層91が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板10が熱によるダメージを受けやすくなる。
これらの金属は、第1低融点金属層91を形成する上で、適した融点及び導電性を備える。
第1低融点金属層91の厚さが、0.1μm未満であると、第1低融点金属層91を構成する金属の量が少ないので、第1導電性粒子71a同士の密着性が向上しにくくなる。
第1低融点金属層91の厚さが、50μmを超えると、第1低融点金属層91が厚いため、加熱時に第1低融点金属層91の形状が大きく変化しやすくなる。そのため、プリント配線板10の形状に歪みが生じやすくなる。
第1低融点金属層91の含有率が1wt%未満であると、第1低融点金属層91を構成する金属の量が少ないので、第1導電性粒子71a同士の密着性が向上しにくくなる。
第1低融点金属層91の含有率が、50wt%を超えると、第1低融点金属層91が厚いため、加熱時に第1低融点金属層91の形状が大きく変化しやすくなる。そのため、プリント配線板10の形状に歪みが生じやすくなる。
第1低融点金属層91がフラックスを含むことにより、第1低融点金属層91を構成する金属が軟化する際に、第1導電性粒子71a同士の密着性が向上しやすくなる。
第1導電性粒子71aと、接着性樹脂72との重量比が上記割合であると、第1導電性粒子71a同士が接触しやすくなる。
従って、第1導電性粒子71a同士の接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
補強部材80の材料は、特に限定されないが、ステンレス鋼、ニッケル、銅、銀、錫、金、パラジウム、アルミニウム、クロム、チタン、亜鉛、またはこれらの合金等であることが望ましい。
これら材料は、補強部材として適した強度と導電性を有する。
補強部材80の表面にニッケル層が形成されている場合、ニッケル層の光沢度は、500以下であることが望ましく、460以下であることがより望ましい。
ニッケル層の光沢度が500以下であると、補強部材80と、接着剤層70との接着面の表面積を広くすることができ、接着力を高く保つことができる。また、ニッケル層は、光沢添加剤を含まず、無光沢であることがさらに望ましい。
このような態様を図示して説明する。
図2~図4は、本発明のプリント配線板の一例を模式的に示す断面図である。
また、第3低融点金属層93は、図4及び図5に示すように補強部材80の全面を覆っていてもよく、補強部材80の一部のみを覆っていてもよい。
これらの金属は、第2低融点金属層92を形成する上で、適した融点及び導電性を備える。
第2低融点金属層92が、融点が300℃以下の金属により形成されていると、容易に第2低融点金属層92が軟化し、基体フィルム60と接着剤層70との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第2低融点金属層92は一度加熱されて軟化することになる。第2低融点金属層92が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、本発明のプリント配線板が熱によるダメージを受けやすくなる。
第2低融点金属層92の厚さが、0.1μm未満であると、第2低融点金属層92を構成する金属の量が少ないので、基体フィルム60と接着剤層70との密着性が向上しにくくなる。
第2低融点金属層92の厚さが、50μmを超えると、第2低融点金属層92が厚いため、加熱時に第2低融点金属層92の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第2低融点金属層92がフラックスを含むことにより、第2低融点金属層92を構成する金属が軟化する際に、基体フィルム60と接着剤層70との密着性が向上しやすくなる。
これらの金属は、第2低融点金属層93を形成する上で、適した融点及び導電性を備える。
第3低融点金属層93が、融点が300℃以下の金属により形成されていると、容易に第3低融点金属層93が軟化し、接着剤層70と補強部材80との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第3低融点金属層93は一度加熱されて軟化することになる。第3低融点金属層93が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第3低融点金属層93の厚さが、0.1μm未満であると、第3低融点金属層93を構成する金属の量が少ないので、接着剤層70と補強部材80との密着性が向上しにくくなる。
第3低融点金属層93の厚さが、50μmを超えると、第3低融点金属層93が厚いため、加熱時に第3低融点金属層93の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第3低融点金属層93がフラックスを含むことにより、第3低融点金属層93を構成する金属が軟化する際に、接着剤層70と補強部材80との密着性が向上しやすくなる。
また、フラックスとしては、特に限定されないが、多価カルボン酸、乳酸、クエン酸、オレイン酸、ステアリン酸、グルタミン酸、安息香酸、グリセリン、ロジン等公知のものを用いることができる。
図5(a)及び(b)は、本発明のプリント配線板の製造方法における導電性粒子準備工程の一例を模式的に示す図である。
図6は、本発明のプリント配線板の製造方法における接着剤層用ペースト作製工程の一例を模式的に示す図である。
図7(a)及び(b)は、本発明のプリント配線板の製造方法における接着剤層形成工程の一例を模式的に示す図である。
図8は、本発明のプリント配線板の製造方法における補強部材設置工程の一例を模式的に示す図である。
図9は、本発明のプリント配線板の製造方法における加熱工程の一例を模式的に示す図である。
まず、図5(a)に示すように、導電性を有さないコア粒子73を準備する。
また、導電性を有さないコア粒子73としては、エポキシ樹脂、フェノール樹脂、ウレタン樹脂、メラミン樹脂、アルキッド樹脂、アクリル樹脂、スチレン樹脂等の熱硬化性樹脂を使用することができる。
第1低融点金属層91を形成する金属として望ましいものは上記の通りであるので、ここでの説明は省略する。
このようにして、第1低融点金属層91が表面に形成されたコア粒子73である第1導電性粒子71aを準備することができる。
次に、図6に示すように、第1導電性粒子71aと、接着性樹脂72とを混合し、接着剤層用ペースト75を作製する。
第1導電性粒子71aと、接着性樹脂72との重量比は、第1導電性粒子:接着性樹脂=30:70~70:30であることが望ましい。
第1導電性粒子71aと、接着性樹脂72との重量比が上記割合であると、第1導電性粒子71a同士が接触しやすくなる。
従って、第1導電性粒子71a同士の接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
次に、ベースフィルム61上にグランド回路62aを含むプリント回路62と絶縁フィルム63とを順次設けてなる基体フィルム60を準備する。そして、グランド回路62aの一部を露出させるために穴部63aを形成する。穴部63aの形成方法は特に限定されず、レーザー加工等の従来の方法を採用することができる。
次に、図7(a)に示すように、基体フィルム60の絶縁層63の上に、接着剤層用ペースト75を塗布し、図7(b)に示すように、接着剤層70を形成する。この際、絶縁層63の穴部63aを接着剤層70が埋め、グランド回路62aと接着剤層70とは接触することになる。
次に、図8に示すように、接着剤層70の上に補強部材80を設置する。設置する補強部材80の大きさや、位置は、製造されるプリント配線板の用途等に応じ調節することが望ましい。
このようにして、基体フィルムと、基体フィルムの上に形成された接着剤層と、接着剤層の上に形成された導電性を有する補強部材とを含むプリント配線板を作製することができる。
次に、図9に示すように、作製されたプリント配線板を加熱することにより、第1低融点金属層を軟化させる。これにより第1導電性粒子同士を接続することにより、第1導電性粒子同士の密着性を向上させる。
これら低融点金属層を形成する方法は、例えば、めっき法を採用することができる。
図10は、本発明のプリント配線板の一例を模式的に示す断面図である。
また、接着剤層170は、導電性粒子171と、接着性樹脂172とを含んでおり、導電性粒子171は、自身が導電性を有する第2導電性粒子171bである。
また、基体フィルム160と接着剤層170との間には、第2低融点金属層192が形成されている。
そのため、グランド回路162aと、補強部材180とは、第2低融点金属層192を介して電気的に接続されていることになる。
接着剤層170の厚さは、特に限定されず、プリント配線板110の用途に合わせて決定することが望ましい。接着剤層170の厚さは、例えば、5~50μmであってもよい。
また、接着性樹脂172には、脂肪酸炭化水素樹脂、C5/C9混合樹脂、ロジン、ロジン誘導体、テルペン樹脂、芳香族系炭化水素樹脂、熱反応性樹脂等の粘着性付与剤が含まれていてもよい。これら粘着性付与剤が含まれていると、接着性樹脂172の粘着性を向上させることができる。
第2導電性粒子171bの平均粒子径が1μm未満であると、第2導電性粒子171bが小さいため、接着剤層170に均一に分散させにくくなる。
第2導電性粒子171bの平均粒子径が200μmを超えると、比表面積が小さくなり、第2導電性粒子171b同士が接触しにくくなる。その結果、接着剤層170の電気抵抗値が上昇しやすくなる。
プリント配線板110では、基体フィルム160と接着剤層170との間には、第2低融点金属層192が形成されている。
そのため、基体フィルム160と接着剤層170との密着性を向上させることができる。
従って、基体フィルム160と接着剤層170との接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
なお、第2低融点金属層192は、図10に示すように基体フィルム160の全面を覆っていてもよく、グランド回路162aの一部のみを覆っていてもよい。
第2低融点金属層192が、融点が300℃以下の金属により形成されていると、容易に第2低融点金属層が軟化し、基体フィルム160と接着剤層170との密着性を好適に向上させることができる。
なお、プリント配線板110を製造する場合、第2低融点金属層192は一度加熱されて軟化することになる。第2低融点金属層192が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板110が熱によるダメージを受けやすくなる。
これらの金属は、第2低融点金属層192を形成する上で、適した融点及び導電性を備える。
第2低融点金属層192の厚さが、0.1μm未満であると、第2低融点金属層192を構成する金属の量が少ないので、基体フィルム160と接着剤層170との密着性が向上しにくくなる。
第2低融点金属層192の厚さが、50μmを超えると、第2低融点金属層192が厚いため、加熱時に第2低融点金属層192の形状が大きく変化しやすくなる。そのため、プリント配線板110の形状に歪みが生じやすくなる。
第2低融点金属層192がフラックスを含むことにより、第2低融点金属層192を構成する金属が軟化する際に、基体フィルム160と接着剤層170との密着性が向上しやすくなる。
第2導電性粒子171bと、接着性樹脂172との重量比が上記割合であると、第2導電性粒子171b同士が接触しやすくなる。
従って、第2導電性粒子同士171b同士の接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
このようなプリント配線板の別の態様について図示して説明する。
図11及び図12は、本発明のプリント配線板の一例を模式的に示す断面図である。
なお、第3低融点金属層193は、図11に示すように補強部材180の全面を覆っていてもよく、補強部材180の一部のみを覆っていてもよい。
第3低融点金属層193が、融点が300℃以下の金属により形成されていると、容易に第3低融点金属層193が軟化し、接着剤層170と補強部材180との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第3低融点金属層193は一度加熱されて軟化することになる。第3低融点金属層193が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第3低融点金属層193の厚さが、0.1μm未満であると、第3低融点金属層193を構成する金属の量が少ないので、接着剤層170と補強部材180との密着性が向上しにくくなる。
第3低融点金属層193の厚さが、50μmを超えると、第3低融点金属層193が厚いため、加熱時に第3低融点金属層193の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第3低融点金属層193がフラックスを含むことにより、第3低融点金属層193を構成する金属が軟化する際に、接着剤層170と補強部材180との密着性が向上しやすくなる。
これら低融点金属層を形成する方法は、例えば、めっき法を採用することができる。
図13は、本発明のプリント配線板の一例を模式的に示す断面図である。
また、接着剤層270は、導電性粒子271と、接着性樹脂272とを含んでおり、導電性粒子271は、導電性を有するコア粒子273に第1低融点金属層291が形成された第3導電性粒子271cである。
また、第3導電性粒子271c同士は、第1低融点金属層291を介して互いに接続している。
そのため、グランド回路262aと、補強部材280とは、第3導電性粒子271cの第1低融点金属層291を介して電気的に接続されていることになる。
接着剤層270の厚さは、特に限定されず、プリント配線板210の用途に合わせて決定することが望ましい。接着剤層270の厚さは、例えば、5~50μmであってもよい。
また、接着性樹脂272には、脂肪酸炭化水素樹脂、C5/C9混合樹脂、ロジン、ロジン誘導体、テルペン樹脂、芳香族系炭化水素樹脂、熱反応性樹脂等の粘着性付与剤が含まれていてもよい。これら粘着性付与剤が含まれていると、接着性樹脂272の粘着性を向上させることができる。
そのため、第1低融点金属層291が表面に形成されたコア粒子273からなる第3導電性粒子271cを含む接着剤層270は、導電性接着剤層として機能することができる。
また、コア粒子273は、導電性を有するので、コア粒子273が剥き出しになり、その箇所で第3導電性粒子271c同士が接触したとしても第3導電性粒子271c同士の間には電流が流れる。従って、摩擦等によりコア粒子273が剥き出しになったとしても、導電性を確保することができる。
第3導電性粒子271cの平均粒子径が1μm未満であると、第3導電性粒子271cが小さいため、接着剤層270に均一に分散させにくくなる。
第3導電性粒子271cの平均粒子径が200μmを超えると、比表面積が小さくなり、第3導電性粒子271c同士が接触しにくくなる。その結果、接着剤層270の電気抵抗値が上昇しやすくなる。
第1低融点金属層291が、融点が300℃以下の金属により形成されていると、容易に第1低融点金属層291が軟化し、第3導電性粒子271c同士の密着性を好適に向上させることができる。
なお、プリント配線板210を製造する場合、第1低融点金属層291は一度加熱されて軟化することになる。第1低融点金属層291が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板210が熱によるダメージを受けやすくなる。
これらの金属は、第1低融点金属層291を形成する上で、適した融点及び導電性を備える。
コア粒子273と、第1低融点金属層291との間にニッケル層が形成されていると、このような合金が形成されることを防ぐことができる。その結果、第3導電性粒子271c同士が効率よく密着することができる。そのため、第1低融点金属層291に用いる錫の量を少なくすることができる。
第1低融点金属層291の厚さが、0.1μm未満であると、第1低融点金属層291を構成する金属の量が少ないので、第3導電性粒子271c同士の密着性が向上しにくくなる。
第1低融点金属層291の厚さが、50μmを超えると、第1低融点金属層291が厚いため、加熱時に第1低融点金属層291の形状が大きく変化しやすくなる。そのため、プリント配線板210の形状に歪みが生じやすくなる。
第1低融点金属層291の含有率が1wt%未満であると、第1低融点金属層291を構成する金属の量が少ないので、第1導電性粒子271a同士の密着性が向上しにくくなる。
第1低融点金属層291の含有率が、50wt%を超えると、第1低融点金属層291が厚いため、加熱時に第1低融点金属層291の形状が大きく変化しやすくなる。そのため、プリント配線板210の形状に歪みが生じやすくなる。
第1低融点金属層291がフラックスを含むことにより、第1低融点金属層291を構成する金属が軟化する際に、第3導電性粒子271c同士の密着性が向上しやすくなる。
第3導電性粒子271aと、接着性樹脂272との重量比が上記割合であると、第3導電性粒子271a同士が接触しやすくなる。
従って、第3導電性粒子同士271a同士の接触のずれが生じることによる電気抵抗値の上昇を抑制することができる。
このような態様を図示して説明する。このような態様を図示して説明する。
図14~図16は、本発明のプリント配線板の一例を模式的に示す断面図である。
また、第3低融点金属層293は、図15及び図16に示すように補強部材280の全面を覆っていてもよく、補強部材280の一部のみを覆っていてもよい。
これらの金属は、第2低融点金属層292を形成する上で、適した融点及び導電性を備える。
第2低融点金属層292が、融点が300℃以下の金属により形成されていると、容易に第2低融点金属層292が軟化し、基体フィルム260と接着剤層270との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第2低融点金属層292は一度加熱されて軟化することになる。第2低融点金属層292が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、本発明のプリント配線板が熱によるダメージを受けやすくなる。
第2低融点金属層292の厚さが、0.1μm未満であると、第2低融点金属層292を構成する金属の量が少ないので、基体フィルム260と接着剤層270との密着性が向上しにくくなる。
第2低融点金属層292の厚さが、50μmを超えると、第2低融点金属層292が厚いため、加熱時に第2低融点金属層292の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第2低融点金属層292がフラックスを含むことにより、第2低融点金属層292を構成する金属が軟化する際に、基体フィルム260と接着剤層270との密着性が向上しやすくなる。
これらの金属は、第3低融点金属層292を形成する上で、適した融点及び導電性を備える。
第3低融点金属層293が、融点が300℃以下の金属により形成されていると、容易に第3低融点金属層293が軟化し、接着剤層270と補強部材280との密着性を好適に向上させることができる。
本発明のプリント配線板を製造する場合、第3低融点金属層293は一度加熱されて軟化することになる。第3低融点金属層293が、融点が300℃を超える金属により形成されていると、この加熱温度が高くなる。そのため、プリント配線板が熱によるダメージを受けやすくなる。
第3低融点金属層293の厚さが、0.1μm未満であると、第3低融点金属層293を構成する金属の量が少ないので、接着剤層270と補強部材280との密着性が向上しにくくなる。
第3低融点金属層293の厚さが、50μmを超えると、第3低融点金属層293が厚いため、加熱時に第3低融点金属層293の形状が大きく変化しやすくなる。そのため、プリント配線板の形状に歪みが生じやすくなる。
第3低融点金属層293がフラックスを含むことにより、第3低融点金属層293を構成する金属が軟化する際に、接着剤層270と補強部材280との密着性が向上しやすくなる。
また、フラックスとしては、特に限定されないが、多価カルボン酸、乳酸、クエン酸、オレイン酸、ステアリン酸、グルタミン酸、安息香酸、グリセリン、ロジン等公知のものを用いることができる。
これら低融点金属層を形成する方法は、例えば、めっき法を採用することができる。
60、160、260 基体フィルム
61、161、261 ベースフィルム
62、162、262 プリント回路
62a、162a、262a グランド回路
63、163、263 絶縁層
63a 穴部
70、170、270 接着剤層
71、171、271 導電性粒子
71a 第1導電性粒子
72、172、272 接着性樹脂
80、180、280 補強部材
91、291 第1低融点金属層
92、192、292 第2低融点金属層
93、293、293 第3低融点金属層
171b 第2導電性粒子
271c 第3導電性粒子
Claims (11)
- ベースフィルム上にグランド回路を含むプリント回路が形成された基体フィルムと、
前記基体フィルムの上に形成された接着剤層と、
前記接着剤層の上に形成された導電性を有する補強部材とを含むプリント配線板であって、
前記接着剤層は、導電性粒子と、接着性樹脂とを含み、
前記導電性粒子は、導電性を有しないコア粒子に第1低融点金属層が形成された第1導電性粒子、自身が導電性を有する第2導電性粒子、及び、導電性を有するコア粒子に第1低融点金属層が形成された第3導電性粒子からなる群から選択される少なくとも1種であり、
前記基体フィルムと前記接着剤層との間には第2低融点金属層が形成されている、又は、前記基体フィルムと前記接着剤層とは直接接触しており、
前記接着剤層と前記補強部材との間には、第3低融点金属層が形成されている、又は、前記接着剤層と前記補強部材とは直接接触しており、
前記プリント配線板は、前記第1低融点金属層、前記第2低融点金属層、及び、前記第3低融点金属層からなる群から選択される少なくとも1種の低融点金属層を備え、
前記グランド回路と、前記補強部材とは、前記第1低融点金属層、前記第2低融点金属層、及び、前記第3低融点金属層からなる群から選択される少なくとも1種の低融点金属層を介して電気的に接続されていることを特徴とするプリント配線板。 - 前記導電性粒子の平均粒子径は、1~200μmである請求項1に記載のプリント配線板。
- 前記第1低融点金属層は、融点が300℃以下の金属により形成されている請求項1又は2に記載のプリント配線板。
- 前記第1低融点金属層の厚さは、0.1~50μmである請求項1~3のいずれかに記載のプリント配線板。
- 前記第1低融点金属層は、フラックスを含む請求項1~4のいずれかに記載のプリント配線板。
- 前記第2低融点金属層は、融点が300℃以下の金属により形成されている請求項1~5のいずれかに記載のプリント配線板。
- 前記第2低融点金属層の厚さは、0.1~50μmである請求項1~6のいずれかに記載のプリント配線板。
- 前記第2低融点金属層は、フラックスを含む請求項1~7のいずれかに記載のプリント配線板。
- 前記第3低融点金属層は、融点が300℃以下の金属により形成されている請求項1~8のいずれかに記載のプリント配線板。
- 前記第3低融点金属層の厚さは、0.1~50μmである請求項1~9のいずれかに記載のプリント配線板。
- 前記第3低融点金属層は、フラックスを含む請求項1~10のいずれかに記載のプリント配線板。
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CN201880010111.7A CN110235530A (zh) | 2017-02-13 | 2018-02-09 | 印制线路板 |
JP2018567515A JPWO2018147424A1 (ja) | 2017-02-13 | 2018-02-09 | プリント配線板 |
US16/480,247 US20190373716A1 (en) | 2017-02-13 | 2018-02-09 | Printed Wiring Board |
KR1020197025284A KR20190115020A (ko) | 2017-02-13 | 2018-02-09 | 프린트 배선판 |
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US17/106,438 Continuation US20210084751A1 (en) | 2017-02-13 | 2020-11-30 | Printed Wiring Board |
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