WO2016052225A1

WO2016052225A1 - Shield film, shield printed wiring board, and methods for manufacturing shield film and shield printed wiring board

Info

Publication number: WO2016052225A1
Application number: PCT/JP2015/076441
Authority: WO
Inventors: 白髪　潤; 村川　昭; 亘冨士川
Original assignee: Dic株式会社
Priority date: 2014-10-03
Filing date: 2015-09-17
Publication date: 2016-04-07
Also published as: JP5975195B1; TW201626865A; JPWO2016052225A1

Abstract

　The present invention provides: a shield film for a printed wiring board in which signal wiring, ground wiring, and a first insulation protection layer are provided on a base insulation substrate, wherein the shield film has an electroconductive adhesive layer laminated on the entire surface of the first insulation protection layer, a copper-plating layer patterned on the electroconductive adhesive layer at a film thickness of 0.5-20 μm and an opening ratio of 40-95%, a layer (A-1) formed on the copper-plating layer using electroconductive ink, a layer (A-2) formed on the inside of the openings in the copper plating layer on the electroconductive adhesive layer by using electroconductive ink, and a second insulation protection layer on the electroconductive adhesive layer, the copper-plating layer, the layer (A-1), and the layer (A-2); and a shield printed wiring board in which the shield film is used. The shield film has high electromagnetic shield performance and a thin profile. In the shield printed wiring board, exceptional reliability of connection with the ground wiring of the printed wiring board is achieved, and a high degree of freedom of design is provided in relation to impedance control.

Description

SHIELD FILM, SHIELD PRINTED WIRING BOARD AND METHOD FOR PRODUCING THEM

The present invention relates to a shield film used for a printed wiring board, a shield printed wiring board using the shield film, and a manufacturing method thereof.

In recent years, in the electronic equipment industry, standards requiring high-speed transmission such as USB 3.0, IEEE 1394, HDMI (registered trademark), etc., have been steadily developed, and high-speed serial communication is often adopted. In addition, LVDS (Low Voltage Differential Signal) transmission, which is one of operation transmissions, is adopted in many devices, and impedance matching of the interface between devices is important. Recently, there has been a demand for higher signal speed, and if the impedance is not matched at the interface between devices, reflection occurs at the end of the transmission path, and waveform distortion occurs due to superposition of the signal wave and the reflected wave. There is a problem that the transmission loss increases. In particular, since the influence of reflected waves due to impedance mismatching increases as the frequency used increases, the impedance of the printed wiring board used at high frequencies is controlled and matched with other boards and components to be connected. It is necessary to use it in the state.

Also, with the miniaturization of electronic devices, there is an increasing demand for thinner printed wiring boards. When the printed wiring board is made thinner, the distance between the signal line and the ground layer becomes closer, the capacitance component of the signal line increases, and in order to maintain the same impedance, the line width (pattern width) of the signal line is reduced. It is necessary to reduce the capacitive component. However, when the pattern width of the signal line becomes narrow, there are problems such as an increase in resistance loss and an increase in DC resistance, and therefore it is required to control the impedance while maintaining a constant pattern width.

On the other hand, with the improvement in performance of electronic devices, noise countermeasures have become important inside the devices. The signal transmission path of the printed wiring board is also considered to be shielded in order to reduce the influence on the other parts due to the noise generated by itself and not to be affected by the noise generated from the other parts. As a method for forming the shield, for example, in a printed wiring board having a signal wiring and a ground wiring on an insulating substrate, a metal thin film layer having a high conductivity and a high electromagnetic wave shielding effect as a shielding material on the signal wiring cover layer And a shielded printed wiring board having a structure in which the ground wiring of the printed wiring board and the metal thin film layer are conducted through a conductive adhesive has been proposed (for example, see Patent Document 1).

However, the above-mentioned shielded printed wiring board can solve the problem of noise countermeasures inside the equipment, but the means for matching the impedance with other equipment to be connected by controlling the impedance of the printed wiring board is a signal wiring pattern. The problem can be solved only by narrowing the width, and the degree of freedom of the pattern of the signal wiring is limited.

Further, as an electromagnetic wave shielding sheet used for a wiring board having signal wiring, it contains a thermosetting resin composition having a glass transition temperature of 0 to 150 ° C., and can flow under conditions of a temperature of 150 ° C. and a pressure of 1 kg / cm ^2. An electromagnetic wave shielding sheet having a bonding layer having insulation and a conductive layer provided on one surface of the bonding layer and having a plurality of openings has been proposed (for example, see Patent Document 2). In this electromagnetic wave shielding sheet, the impedance of the printed wiring board is adjusted by providing an opening in the conductive layer and directly connecting to the ground wiring of the printed wiring board through a through hole provided in the printed wiring board.

However, in the printed wiring board using the electromagnetic wave shielding sheet, the impedance can be adjusted by appropriately setting the shape and the opening ratio of the opening of the electromagnetic wave shielding sheet, but the opening ratio is as high as 40% or more. In such a case, there is a problem that the performance of shielding electromagnetic waves is greatly reduced.

Furthermore, in the printed wiring board using the electromagnetic wave shielding sheet, the conductive layer of the electromagnetic wave shielding sheet and the ground wiring of the printed wiring board are directly connected, so the hardness of the conductive layer, the line width of the pattern, the printed wiring There is a problem that the size of the through hole provided in the plate is limited, and the connection reliability is insufficient. For example, when the line width of the pattern of the conductive layer of the electromagnetic wave shielding sheet is made thicker than the ground wiring of the printed wiring board, it becomes difficult to connect the conductive layer and the ground wiring. Since the adhesion area of the layer becomes very small, there is a problem that connection reliability becomes insufficient. Similarly, when the through hole provided on the ground wiring of the printed wiring board is small, the connection reliability is insufficient. Furthermore, if the insulating protective layer of the printed wiring board is thick, the height of the through hole provided on the ground wiring also increases, and if the conductive layer of the electromagnetic wave shield sheet is not flexible, the conductive layer is disconnected at the step of the through hole. There was also a problem to do.

On the other hand, as an impedance control shield film, an impedance control shield film including an impedance control film having an open metal layer and having a shield layer on the surface opposite to the open metal layer has been proposed (see, for example, Patent Document 3). . In this impedance control shield film, the impedance of the printed wiring board is adjusted by the opening metal layer, and unnecessary radiation that cannot be shielded by the opening metal layer is shielded by the shield layer that is a non-opening metal layer. Can be compatible.

However, the printed wiring board using the impedance control shield film described above requires two layers, an open metal layer and a non-open metal layer (shield layer), and the shield film as a whole becomes thick. There is a problem that it is difficult to meet the demand for thinner printed wiring boards.

Japanese Patent Laid-Open No. 7-122882 JP 2013-168643 A JP 2006-24824 A

The problems to be solved by the present invention can be applied to a printed wiring board, the impedance of the printed wiring board can be controlled without reducing the pattern width of the signal wiring, and the electromagnetic wave shielding property is high as a noise countermeasure. Furthermore, it is to provide a thin shield film capable of reducing the thickness of the printed wiring board. Another object of the present invention is to provide a shielded printed wiring board having excellent connection reliability between the shield film and the ground wiring of the printed wiring board and having a high degree of design freedom in impedance control. Furthermore, it is providing the manufacturing method of the said shield film and a shield printed wiring board.

As a result of diligent research to solve the above problems, the present inventors have established a conductive adhesive layer, a patterned copper plating layer on a printed wiring board provided with a signal wiring, a ground wiring, and an insulating protective layer, By providing a shield film composed of a patterned conductive ink layer and insulating protective layer, the impedance of the printed wiring board can be controlled without reducing the pattern width of the signal wiring, and high electromagnetic waves can be used as a noise countermeasure. A thin shield film that has shielding properties and can reduce the thickness of the printed wiring board is obtained. Excellent connection reliability between the shield film and the ground wiring of the printed wiring board, and freedom of design in impedance control The present invention has been completed by finding that a shield printed wiring board having a high thickness can be obtained.

That is, the present invention is a shield film for a printed wiring board in which signal wiring, ground wiring, and a first insulating protective layer are provided on a base insulating base material,
A conductive adhesive layer laminated on the entire surface of the first insulating protective layer;
A copper plating layer patterned with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95% on the conductive adhesive layer;
A layer (A-1) formed using a conductive ink on the copper plating layer;
A layer (A-2) formed using a conductive ink inside the opening of the copper plating layer on the conductive adhesive layer;
A shield film comprising the conductive adhesive layer, the copper plating layer, the layer (A-1), and a second insulating protective layer on the layer (A-2), and the shield film The present invention relates to a shield printed wiring board. Moreover, it is related with the manufacturing method of the said shield film and a shield printed wiring board.

The shield film and shield printed wiring board of the present invention are related to the impedance control required for a printed wiring board used at a high frequency, and are not controlled only by the pattern width of the signal wiring, but the copper plating layer pattern on the shield film side. By making the aperture ratio one factor of impedance control, impedance matching can be achieved while maintaining the freedom of the line width of the signal wiring. Therefore, for example, it can be suitably used as a shield printed wiring board used inside an electronic device such as a mobile phone, a notebook computer, a smartphone, a tablet terminal, a wearable device, a digital still camera, and a digital video camera.

Furthermore, since the shield film of the present invention can be made thin, it can cope with the thinning of smartphones and tablet terminals that have been progressing in recent years.

FIG. 1 is a cross-sectional view of a shielded printed wiring board according to the present invention. FIG. 2 is a cross-sectional view of the shield printed wiring board of the present invention, in which a polymer layer is provided between a second insulating protective layer and a layer formed using conductive ink. FIG. 3 is a cross-sectional view of the shield printed wiring board of the present invention, in which a polymer layer is provided between the second insulating protective layer and a layer formed using conductive ink, and the layer is formed using conductive ink. An electroless copper plating layer is provided on the surface opposite to the surface in contact with the polymer layer. FIG. 4 is a plan view of a pattern of a copper plating layer and a pattern of a conductive ink layer or an electroless copper plating layer as viewed from the conductive adhesive layer side of the shield printed wiring board of the present invention. FIG. 5 is a perspective view of a pattern of a copper plating layer and a pattern of a conductive ink layer or an electroless copper plating layer as seen from the conductive adhesive layer side of the shield printed wiring board of the present invention. FIG. 6 is a plan view of a pattern printed with conductive ink when the shield printed wiring board of the present invention was produced in Example 1. FIG.

The shield film of the present invention is a shield film for a printed wiring board in which a signal wiring, a ground wiring, and a first insulating protective layer are provided on a base insulating base material,
A conductive adhesive layer laminated on the entire surface of the first insulating protective layer;
A copper plating layer patterned with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95% on the conductive adhesive layer;
A layer (A-1) formed using a conductive ink on the copper plating layer;
A layer (A-2) formed using a conductive ink inside the opening of the copper plating layer on the conductive adhesive layer;
A second insulating protective layer is provided on the conductive adhesive layer, the copper plating layer, the layer (A-1), and the layer (A-2).

The base insulating base material is a base material for a printed wiring board. Examples of the material of the base insulating base material include, for example, polyester resins such as polyimide, polyamideimide, polyamide, and polyethylene terephthalate, polyethylene naphthalate, polycarbonate, ABS (acrylonitrile-butadiene-styrene) resin, acrylic resin such as polymethyl methacrylate, Fluorine resin such as phenol resin, polyvinylidene fluoride, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene, polypropylene, polyurethane, LCP (liquid crystal polymer), PEEK (polyether ether ketone) resin, PEI (polyether imide) resin , PPS (polyphenylene sulfide) resin, PSF (polysulfone) resin, PES (polyethersulfone) resin, polyarylate resin, PBT ( Ribbylene terephthalate) resin, silicone resin, unsaturated polyester resin, polyacetal, nylon, ceramics, alumina, mullite, steatite, forsterite, zirconia, glass, glass / epoxy resin, glass polyimide, paper phenol, cellulose nanofiber, etc. Can be mentioned.

As the base insulating base material, for example, a base material made of synthetic fibers such as polyester fiber, polyamide fiber, and aramid fiber; natural fibers such as cotton and hemp can be used. The fibers may be processed in advance.

As the base insulating substrate, it is preferable to use a flexible and flexible support when the shield printed wiring board of the present invention to be described later is used for applications that require bending flexibility. Specifically, it is preferable to use a film or sheet-like support.

Examples of the film or sheet-like base insulating base material include a polyethylene terephthalate film, a polyimide film, a polyethylene naphthalate film, and a liquid crystal polymer (LCP) film.

In addition, the base insulating base material improves the adhesion with signal wiring and ground wiring, which will be described later, so that the surface is roughened by sandblasting, solvent treatment, etc. (Corona discharge treatment, atmospheric pressure plasma treatment), chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet ray / electron beam irradiation treatment, oxidation treatment, etc. can be used.

When the shape of the base insulating substrate is a film or sheet, the thickness of the film or sheet support is preferably about 1 to 5,000 μm, and preferably about 1 to 300 μm. It is more preferable that When the conductive pattern of the present invention is used for a flexible printed circuit board or the like that requires flexibility, it is preferable to use a film-like film having a thickness of about 1 to 200 μm as the base insulating base material. .

As the base insulating base material, a commercially available copper-clad base material can be used in order to form signal wiring and ground wiring described later. When using a copper clad base material, after providing a resist material on a copper clad base material and exposing a pattern with a photomask, copper other than a wiring part can be removed by an etching process to form a wiring pattern.

The signal wiring and ground wiring can be made of the above-described copper-based wiring, and may be composed of other conductive materials, for example, by printing conductive ink mainly composed of silver. It is also possible to use the formed wiring pattern. Further, the conductive ink pattern can be made into a wiring by thickening it by copper plating, nickel plating or the like.

The shield printed wiring board of the present invention is provided with a first insulating protective layer on the signal wiring and the ground wiring. Examples of the first insulating protective layer include a polyimide film or the like coated with an adhesive, a photosensitive coverlay film or the like having a photosensitivity and capable of forming a pattern by exposure and development, a liquid coverlay. Alternatively, an insulating protective layer can be formed by applying a liquid material such as a photosensitive liquid coverlay or a solder resist.

Next, the shield film of the present invention comprises a conductive adhesive layer laminated on the entire surface of the first insulating protective layer, a film thickness of 0.5 to 20 μm, and an aperture ratio of 40 to 95 on the conductive adhesive layer. A copper plating layer patterned with%, a layer (A-1) formed using a conductive ink on the copper plating layer, and an opening inside the copper plating layer on the conductive adhesive layer, A shield film comprising a layer (A-2) formed using a conductive ink and a second insulating protective layer.

The conductive adhesive layer is made of an adhesive resin containing a conductive substance. Examples of the conductive substance include metal plating such as copper, silver, nickel, and aluminum, metal whiskers, and silver plating on copper powder. Silver-coated copper powder, silver-coated nickel powder obtained by applying silver plating to nickel powder, gold-coated nickel powder obtained by applying gold plating to nickel powder, fillers obtained by applying metal plating to carbon, resin particles and glass beads, etc. . These conductive materials can be used alone or in combination of two or more.

The adhesive resin includes styrene resin, vinyl acetate resin, polyester resin, polyolefin resin such as polyethylene and polypropylene, amide resin, amideimide resin, styrene-butadiene resin, acrylonitrile-butadiene resin, (meth) acryl-butadiene resin, (meth ) Thermoplastic resins such as acrylic resins and urethane resins; Thermosetting resins such as phenol resins, epoxy resins, melamine resins, and alkyd resins; UV curable resins such as urethane acrylates, epoxy acrylates, and acrylic acrylates. These adhesive resins can be used alone or in combination of two or more.

The shield film of the present invention has a copper plating layer patterned with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95% on the conductive adhesive layer. The pattern of the copper plating layer is not particularly limited, but can be appropriately selected according to required shielding properties, impedance to be controlled, and the like. The specific pattern of the copper plating layer is preferably a mesh pattern, and the shape of the opening is a triangle such as a regular triangle, an isosceles triangle, a right triangle; a square, a rectangle, a rhombus, a parallelogram, a trapezoid, and the like. (Positive) pentagons, (positive) hexagons, (positive) octagons, (positive) dodecagons, etc. (positive) n-gons (n is an integer greater than or equal to 5); circles, ellipses, stars, etc. Examples include geometric figures. It is preferable that the openings are arranged at equal intervals because of excellent shielding properties against electromagnetic waves. Further, the aperture ratio of the pattern is preferably in the range of 40 to 95%. The aperture ratio is an important factor in controlling the impedance of the shield printed wiring board. When the aperture ratio is less than 40%, the impedance can be controlled without adjusting the line width of the signal wiring of the shield printed wiring board. By reducing the range and setting the aperture ratio to 95% or less, the impedance of the signal line of the shield printed wiring board can be set to a desired value, and the capacitance can be reduced to prevent the waveform from being blunted. In addition, the aperture ratio in this invention is an aperture ratio when the part which does not have a copper plating layer in the said copper plating layer is made into an opening part. Further, the layer (A-2) formed using the conductive ink located inside the opening of the copper plating layer is referred to as a non-opening portion inside the opening, and may be referred to as an opening internal pattern.

The film thickness of the copper plating layer is in the range of 0.5 to 20 μm. By setting the thickness of the copper plating layer to 0.2 μm or more, the impedance of the signal line of the shield printed wiring board can be set to a desired value, and the capacitance can be reduced to prevent the waveform from being blunted. When the thickness of the copper plating layer exceeds 20 μm, it becomes difficult to satisfy the requirement of thinning the shield printed wiring board itself, and the flexibility is greatly reduced when used as a flexible printed wiring board. There is. Further, the thickness of the copper plating layer is preferably in the range of 0.5 to 8 μm.

Examples of the method of forming the copper plating layer include a method of removing the pattern of the opening from the copper foil by etching, but this method has a problem that the manufacturing method is complicated and the copper plating layer is difficult to be thinned. . Therefore, in the present invention, the copper plating layer can be easily patterned with a desired aperture ratio, and the degree of freedom in design in controlling the impedance is increased. Therefore, a layer formed using a conductive ink described later. After producing the pattern in (A-1), the copper plating layer is formed thereon.

The conductive ink is used for producing a pattern as a base of a copper plating layer as described above, and is excellent in adhesion to a copper plating layer formed on the copper plating layer and plating deposition at the time of copper plating. Therefore, those containing metal nanoparticles as the conductive substance (a2) are preferable. Furthermore, since the said metal nanoparticle is excellent in adhesiveness with the 2nd insulating protective layer mentioned later, it is preferable that it is the metal nanoparticle disperse | distributed with the polymer dispersing agent.

The polymer dispersant is preferably a polymer having a functional group coordinated to the metal nanoparticles. Examples of the functional group include a carboxyl group, an amino group, a cyano group, an acetoacetoxy group, a phosphorus atom-containing group, a thiol group, a thiocyanato group, and a glycinato group.

Examples of the metal nanoparticles include a transition metal or a compound thereof, and an ionic transition metal is preferable among the transition metals. Examples of the ionic transition metal include metals such as copper, silver, gold, nickel, palladium, platinum, and cobalt, and composites of these metals. These metal nanoparticles can be used alone or in combination of two or more. Among these metal nanoparticles, silver nanoparticles are preferable from the viewpoints of handling problems such as oxidative degradation and cost.

In addition, the conductive substance (a2) contained in the conductive ink can use a plating nucleating agent in place of the metal nanoparticles. In that case, an oxide of the transition metal, a metal whose surface is coated with an organic substance, or the like can be used. These plating nucleating agents can be used alone or in combination of two or more.

The transition metal oxide is usually in an inactive (insulating) state. For example, the metal is exposed by treatment with a reducing agent such as dimethylaminoborane to impart activity (conductivity). be able to.

Further, examples of the metal whose surface is coated with the organic substance include those in which a metal is contained in resin particles (organic substance) formed by an emulsion polymerization method or the like. These are usually in an inactive (insulating) state. However, for example, by removing the organic substance using a laser or the like, the metal can be exposed to impart activity (conductivity).

The conductive substance (a2) is preferably in the form of particles having an average particle diameter of about 1 to 100 nm, preferably having an average particle diameter of 1 to 50 nm. Compared to the case of using a conductive material having an average particle size of 1, a fine conductive pattern can be formed, and the resistance value after firing described later can be further reduced, which is more preferable. In the present invention, the average particle diameter is a volume average value measured by a dynamic light scattering method after diluting the conductive substance (a2) with a dispersion good solvent. For this measurement, “Nanotrack UPA” manufactured by Microtrack Corporation can be used.

The shield film of the present invention has a layer (A-2) formed using a conductive ink inside the opening of the patterned copper plating layer. The layer (A-2) exhibits a function of enhancing the shielding property of electromagnetic waves by filling the opening of the copper plating layer. The pattern of the layer (A-2) is not particularly limited in shape, but can be appropriately selected according to the required electromagnetic shielding effect. In order to enhance the electromagnetic shielding performance, The layer (A-2) is preferably formed in the range of 15 to 95% of the opening area of the copper plating layer, and more preferably in the range of 40 to 95%. The layer (A-2) may be in contact with the copper plating layer, but when the copper plating layer is produced by an electrolytic copper plating method described later, the layer (A-2) is a copper plating layer. Preferably it is not in contact with.

Specific pattern shapes of the layer (A-2) include, for example, triangles such as regular triangles, isosceles triangles, and right triangles; squares such as squares, rectangles, rhombuses, parallelograms, and trapezoids; (positive) pentagons , (Positive) hexagons, (positive) octagons, (positive) n-gons such as dodecagons (n is an integer of 5 or more); geometric shapes such as circles, ellipses, and stars; spirals; Examples of the shape include a ring shape, a coil shape, and a spiral shape.

The film thickness of the layer (A-2) is preferably in the range of 0.02 to 2 μm. When the film thickness of the layer (A-2) is 0.02 μm or more, the electromagnetic wave shielding effect of the shield printed wiring board can be enhanced. By setting the film thickness of the layer (A-2) to less than 2 μm, it is possible to provide a difference in film thickness from the copper plating layer. A thickness smaller than the film thickness is preferable because it becomes easy to adjust the impedance of the shield printed wiring board to a desired value.

The film thickness of the copper plating layer is preferably 3 to 100 times the film thickness of the layer (A-2). That is, by reducing the film thickness of the metal layer inside the opening and increasing the copper plating layer of the opening pattern part, the impedance can be set to a desired value, and the capacitance can be reduced to prevent the waveform from being blunted. Furthermore, electromagnetic wave shielding can be achieved.

As the conductive ink constituting the layer (A-2), the same ink as the layer (A-1) can be used.

The layer (A-2) may be formed of only conductive ink, but a metal plating layer may be formed on the conductive ink. Although there is no restriction | limiting in particular as a metal plating layer, Copper, nickel, gold | metal | money, silver, platinum, palladium, chromium, tin etc. are mentioned. As a method for plating the layer (A-2), an electroless plating method can be used.

In the electroless plating method, for example, the metal contained in the electroless plating solution is deposited by bringing the electroless plating solution into contact with the conductive material constituting the pattern of the layer (A-2). It is the method of forming the electroless-plating layer (coating) which consists of.

Examples of the electroless plating solution include those containing a metal, a reducing agent, and a solvent such as an aqueous medium or an organic solvent.

Examples of the reducing agent include dimethylaminoborane, hypophosphorous acid, sodium hypophosphite, dimethylamine borane, hydrazine, formaldehyde, sodium borohydride, phenol and the like.

In addition, as the electroless plating solution, if necessary, monocarboxylic acids such as acetic acid and formic acid; dicarboxylic acid compounds such as malonic acid, succinic acid, adipic acid, maleic acid, and fumaric acid; malic acid, lactic acid, glycol Hydroxycarboxylic acid compounds such as acid, gluconic acid, citric acid; amino acid compounds such as glycine, alanine, iminodiacetic acid, arginine, aspartic acid, glutamic acid; iminodiacetic acid, nitrilotriacetic acid, ethylenediaminediacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, etc. Organic acids such as aminopolycarboxylic acid compounds or soluble salts of these organic acids (sodium salts, potassium salts, ammonium salts, etc.); complexing agents such as amine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, etc. And the like can be used ones.

The electroless plating solution is preferably used in the range of 20 to 98 ° C.

The layer (A-1) and the layer (A-2) formed using the conductive ink are formed on the second insulating protective layer described later in the manufacturing method of the present invention. In order to further improve the adhesion between the surface of the two insulating protective layers and the layer (A-1) and the layer (A-2), the polymer forming the second insulating protective layer is a reactive functional group described later. Those having the group [Y] are preferred.

Even when the polymer forming the second insulating protective layer described later does not have the reactive functional group [Y] described later, the polymer is applied to the surface of the second insulating protective layer, dried, and dried. After providing the molecular layer (B), the layer (A-1) and the layer (A-2) are formed thereon, whereby the surface of the second insulating protective layer described later and the layer (A-1) are formed. ) And the layer (A-2) can be further improved. The polymer forming the polymer layer (B) preferably has a reactive functional group [Y] described later.

When the polymer layer (B) having a reactive functional group [Y] described later is provided, the conductive ink further improves the adhesion between the copper plating layer and a second insulating protective layer described later. Therefore, what contains the compound (a1) which has reactive functional group [X], and the said electroconductive substance (a2) is preferable.

The reactive functional group [X] possessed by the compound (a1) is involved in binding to the reactive functional group [Y] described later, and specific examples include an amino group, an amide group, and an alkylolamide group. , Carboxyl group, anhydrous carboxyl group, carbonyl group, acetoacetoxy group, epoxy group, alicyclic epoxy group, oxetane ring, vinyl group, allyl group, (meth) acryloyl group, (blocked) isocyanate group, (alkoxy) silyl group Etc., silsesquioxane compounds, and the like.

In particular, the reactive functional group [X] is preferably a basic nitrogen atom-containing group in order to further improve the adhesion to the second insulating protective layer described later.

Examples of the basic nitrogen atom-containing group in the compound having a basic nitrogen atom-containing group include an imino group, a primary amino group, and a secondary amino group.

In addition, by using the compound (a1) having a plurality of basic nitrogen atom-containing groups in one molecule, one of the basic nitrogen atom-containing groups is converted into the layer (A-1) and the layer (A-2). ), The polymer that forms the second insulating protective layer described later, or the reactive functional group [Y] that the polymer that forms the polymer layer (B) has. The other contributes to the interaction with the conductive material (a2) such as silver contained in the layer (A-1) and the layer (A-2), and finally obtains the copper plating layer This is preferable because the adhesion to the second insulating protective layer can be further improved.

Since the compound (a1) having a basic nitrogen atom-containing group can further improve the dispersion stability of the conductive substance (a2) and the adhesion to the second insulating protective layer described later, a polyalkyleneimine, or A polyalkyleneimine having a polyoxyalkylene structure containing an oxyethylene unit is preferred.

The polyalkyleneimine having the above may be a linear bond of polyethyleneimine and polyoxyalkylene, and the polyoxyalkylene is present in the side chain of the main chain composed of polyethyleneimine. May be grafted.

Specific examples of the polyalkyleneimine having the polyoxyalkylene structure include a block copolymer of polyethyleneimine and polyoxyethylene, and an addition reaction of ethylene oxide with a part of imino group present in the main chain of polyethyleneimine. Examples thereof include those obtained by introducing a polyoxyethylene structure, those obtained by reacting an amino group possessed by polyalkyleneimine, a hydroxyl group possessed by polyoxyethylene glycol, and an epoxy group possessed by an epoxy resin.

Examples of commercially available products of the polyalkyleneimine include “PAO2006W”, “PAO306”, “PAO318”, “PAO718” and the like of “Epomin (registered trademark) PAO series” manufactured by Nippon Shokubai Co., Ltd.

The number average molecular weight of the polyalkyleneimine is preferably in the range of 3,000 to 30,000.

When the reactive functional group [X] of the compound (a1) is a carboxyl group, an amino group, a cyano group, an acetoacetoxy group, a phosphorus atom-containing group, a thiol group, a thiocyanato group, a glycinato group, etc. Since the functional group also functions as a functional group that coordinates with the metal nanoparticles, the compound (a1) can also be used as a polymer dispersant for the metal nanoparticles.

The conductive ink preferably has an appropriate viscosity using a solvent in order to impart printability in various printing methods described later. Examples of the solvent include aqueous media such as distilled water, ion-exchanged water, pure water, and ultrapure water; and organic solvents such as alcohol solvents, ether solvents, ketone solvents, and ester solvents.

Examples of the alcohol solvent or ether solvent include methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol. , Tridecanol, tetradecanol, pentadecanol, stearyl alcohol, allyl alcohol, cyclohexanol, terpineol, dihydroterpineol, 2-ethyl-1,3-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol , Dipropylene glycol, 1,2-butanediol, 1,3-butanedio 1,4-butanediol, 2,3-butanediol, glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol Monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol mono Chirueteru, and the like.

Examples of the ketone solvent include acetone, cyclohexanone, methyl ethyl ketone, and the like. Examples of the ester solvent include ethyl acetate, butyl acetate, 3-methoxybutyl acetate, 3-methoxy-3-methyl-butyl acetate and the like. Furthermore, other organic solvents include nonpolar solvents such as cyclohexane, toluene, octane, nonane, decane, dodecane, tridecane, tetradecane, cyclooctane, xylene, mesitylene, ethylbenzene, dodecylbenzene, tetralin, trimethylbenzene, etc. These solvents can be used in combination with the above as necessary. Furthermore, a solvent such as mineral spirit or solvent naphtha, which is a mixed solvent, can be used in combination.

The conductive ink can be produced, for example, by mixing the polymer dispersant, the conductive substance, and, if necessary, the solvent. Specifically, an ion solution of the conductive substance prepared in advance is added to a medium in which a compound having a polyalkyleneimine chain, a hydrophilic segment, and a hydrophobic segment is dispersed, and the metal ions are reduced. Can be manufactured by.

In addition, the conductive ink may contain a surfactant, an erasing agent, or the like, if necessary, in order to improve the dispersion stability of the conductive substance in a solvent such as an aqueous medium or an organic solvent and the wettability to the coated surface. Foaming agents, rheology modifiers, etc. may be added.

In the present invention, the conductive ink is printed on a second insulating protective layer to be described later to form a pattern comprising the layer (A-1) and the layer (A-2). Examples of the printing method include an inkjet printing method, a reverse printing method, a flexographic printing method, a screen printing method, a gravure printing method, and a gravure offset printing method. Among these printing methods, when changing the pattern of the copper plating layer in order to control the impedance of the shield printed wiring board, it is not necessary to prepare a printing plate corresponding to the pattern, and can easily cope with the pattern change. Therefore, the ink jet printing method is preferable.

As the ink jet printing method, what is generally called an ink jet printer can be used. Specific examples include “Konica Minolta EB100, XY100” (manufactured by Konica Minolta IJ Co., Ltd.), “Dimatics Material Printer DMP-3000, DMP-2831” (manufactured by Fuji Film Co., Ltd.), and the like.

In addition, when producing a high-definition metal layer pattern, a reverse printing method that is excellent in fine line printing accuracy is preferable.

As the reversal printing method, a letterpress reversal printing method and an intaglio reversal printing method are known.For example, the conductive ink is applied to the surface of various blankets, and is brought into contact with a plate from which a non-image portion protrudes. The pattern is formed on the surface of the blanket or the like by selectively transferring the conductive ink corresponding to the image area to the surface of the plate, and then the pattern is formed on the second insulating protective layer ( And a method of transferring to the surface).

Further, as described above, the polymer layer (B) is provided for the purpose of further improving the adhesion between the surface of the second insulating protective layer, which will be described later, and the layer (A-1) and the layer (A-2). In this case, examples of the polymer that forms the polymer layer (B) include urethane resin, vinyl resin, urethane-vinyl composite resin, epoxy resin, imide resin, amide resin, melamine resin, phenol resin, polyvinyl alcohol, What contains various resins, such as polyvinylpyrrolidone, and a solvent is mentioned.

Among the resins used as the polymer (B), urethane resin, vinyl resin, and urethane-vinyl composite resin are preferable. Urethane resin having a polyether structure, urethane resin having a polycarbonate structure, urethane resin having a polyester structure, and acrylic resin And one or more resins selected from the group consisting of urethane-acrylic composite resins are more preferable. A urethane-acrylic composite resin is more preferable because a conductive pattern having excellent adhesion and conductivity can be obtained.

When the conductive ink contains the compound (a1) having the reactive functional group [X], the polymer forming the polymer layer (B) is reactive with the reactive functional group [X]. The compound (b1) having a functional group [Y] having Examples of the compound (b1) having the reactive functional group [Y] include an amino group, an amide group, an alkylolamide group, a carboxyl group, an anhydrous carboxyl group, a carbonyl group, an acetoacetoxy group, an epoxy group, and an alicyclic epoxy. Group, oxetane ring, vinyl group, allyl group, (meth) acryloyl group, (blocked) isocyanate group, (alkoxy) silyl group-containing compound, silsesquioxane compound and the like.

In particular, when the compound (a1) having the reactive functional group [X] in the conductive ink is the compound (a1) having the basic nitrogen atom-containing group, the polymer layer (B) is formed. The polymer has a reactive functional group [Y] such as carboxyl group, carbonyl group, acetoacetoxy group, epoxy group, alicyclic epoxy group, alkylolamide group, isocyanate group, vinyl group, (meth) acryloyl group, allyl group. It is preferable that the adhesion between the finally obtained metal layer and the second insulating protective layer can be improved.

Examples of the method for applying the polymer forming the polymer layer (B) to the surface of the second insulating protective layer described later include a gravure method, a coating method, a screen method, a roller method, a rotary method, and a spray method. Can be mentioned.

Further, the surface of the second insulating protective layer to be described later is improved in adhesion with the polymer layer (B), for example, plasma discharge treatment method such as corona discharge treatment method; dry treatment such as ultraviolet treatment method. Method: Surface treatment may be performed by a wet treatment method using water, an acidic or alkaline chemical solution, an organic solvent, or the like.

After applying the polymer forming the polymer layer (B) to the surface of the second insulating protective layer described later, as a method of removing the solvent contained in the coating layer, for example, using a dryer, A method of volatilizing the solvent is common. The drying temperature is preferably set to a temperature within which the solvent can be volatilized and does not adversely affect the support.

The thickness of the polymer (B) layer formed using the polymer (B) is in the range of 5 to 5,000 nm because the adhesion between the second insulating protective layer and the metal layer can be further improved. The range of 10 to 500 nm is more preferable.

Further, the polymer (B) can be used as it is as the second insulating protective layer, and further, the polymer (B) can be mixed and used in the second insulating protective layer. In this case, the polymer (B) needs to be present in a portion of the second insulating protective layer in contact with the conductive ink.

Next, the baking step performed after applying the conductive ink to form a pattern as a plating base with the conductive ink is to adhere and bond the conductive substances contained in the conductive ink. In order to form a plating base pattern having conductivity. The firing is preferably performed at a temperature range of 80 to 300 ° C. for about 1 to 200 minutes. Here, in order to obtain a plating base pattern having excellent adhesion to the second insulating protective layer, it is more preferable that the firing temperature be in the range of 100 to 200 ° C.

Although the firing may be performed in the air, part or all of the firing step may be performed in a reducing atmosphere in order to prevent the conductive material from being oxidized.

The baking step can be performed using, for example, an oven, a hot air drying furnace, an infrared drying furnace, laser irradiation, microwave, light irradiation (flash irradiation apparatus), or the like.

The pattern composed of the layer (A-1) and the layer (A-2) formed using the conductive ink by the method as described above is in the range of 80 to 99.9% by mass in the pattern. The conductive material is preferably contained in a range of 0.1 to 20% by mass.

The film thickness of the layer (A-1) and the layer (A-2) formed using the conductive ink can form a conductive pattern having a low resistance and excellent conductivity. The range of is preferable.

Next, in the shield film and shield printed wiring board of the present invention, the layer (A-1) formed using the conductive ink is used as a main conductive layer on the shield film side as a plating base pattern, and a film is formed thereon. It has a copper plating layer patterned with a thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95%. On the other hand, in Patent Document 2, as a conductive layer, a method of printing conductive ink or conductive paste in a predetermined pattern on a base film, a method of forming an opening by etching a metal foil, It is disclosed that a metal layer having a predetermined pattern is formed by vapor deposition or sputtering, and that a wire mesh is used as such a conductive layer. Patent Document 2 discloses that the material of the conductive layer is preferably a metal such as gold, silver, or copper and an alloy thereof, a conductive filler-containing resin, a conductive polymer, or the like. ing. However, when a conductive filler-containing resin is used as a conductive ink or conductive paste as the conductive layer material, the conductive layer itself is poorly conductive and may deteriorate the transmission loss of signal lines on the printed wiring board. It has been known. Moreover, in the method of forming the opening by etching the metal foil, the manufacturing process becomes complicated, the shield printed wiring board becomes expensive, and the thickness of the conductive layer is arbitrarily adjusted (thinned). It becomes difficult. Further, in the method of forming a metal layer having a predetermined pattern by metal vapor deposition or sputtering, only a thin conductive layer can be formed, and there is also a problem with a method of patterning openings. Further, in the method using a metal wire mesh, it is difficult to make the pattern of the conductive layer thin, and there is a restriction in reducing the area of the opening. In the present invention, as the conductive layer on the shield film side, the layer (A-1) having a pattern formed with the conductive ink is used as a plating base, and a copper plating layer obtained by performing copper plating thereon is used. All the above problems can be solved.

Examples of the method for forming the copper plating layer include wet plating methods such as an electrolytic plating method and an electroless plating method, and the copper plating layer may be formed by combining two or more of these plating methods.

Among the plating methods, the adhesion between the pattern of the layer (A-1) and the copper plating layer formed by the plating method is further improved, and a pattern having excellent conductivity can be obtained. A wet plating method such as a plating method or an electroless plating method is preferred, and an electrolytic plating method is more preferred because of excellent productivity and mechanical properties of the resulting metal film. Further, when copper plating is performed only on the layer (A-1) which is a pattern having an opening, it is preferable to carry out by an electrolytic plating method.

In the electrolytic plating method, for example, current is applied in a state where an electrolytic plating solution is in contact with the surface of the metal constituting the layer (A-1) or the electroless plating layer (coating) formed by the electroless treatment. As a result, a metal such as copper contained in the electrolytic plating solution is deposited on the surface of the conductive material constituting the layer (A-1) placed on the cathode to form an electrolytic plating layer (metal coating). It is a method to do.

Examples of the electrolytic plating solution include those containing copper sulfide, sulfuric acid, and an aqueous medium. Specifically, what contains copper sulfate, sulfuric acid, and an aqueous medium is mentioned.

The electrolytic plating solution is preferably used in the range of 20 to 98 ° C.

The electrolytic plating treatment method is preferable because it has good workability without using a highly toxic substance as compared with the electroless plating method. Electrolytic copper plating is preferable because it can shorten the plating time and control the thickness of the plating as compared with electroless copper plating. Furthermore, the copper plating layer obtained by electrolytic copper plating has excellent mechanical properties, is difficult to break even when bent, and has excellent flexibility. It is preferable to use the formed copper plating layer.

The copper plating layer may be formed by laminating another metal plating layer on the copper plating layer. When a nickel plating layer, a gold plating layer, or a tin plating layer is provided, the surface of the copper plating layer is deteriorated by oxidation or corroded. Can be prevented.

The thickness of the copper plating layer formed by the above plating method is preferably in the range of 0.5 to 20 μm because it is excellent in conductivity as a conductive layer and can meet the demand for thinning the shield printed wiring board. In addition, when a copper plating layer is formed by an electrolytic plating method, the thickness of the layer can be adjusted by controlling the processing time, current density, the amount of plating additive used, etc. in the copper plating process. .

In the shielded printed wiring board of the present invention, a second insulating protective layer is provided on the pattern of the copper plating layer, the layer (A-1) and the layer (A-2). The second insulating protective layer comprises an insulating resin sheet or film, or an insulating resin coating layer. Examples of the insulating resin sheet or film include polyester film, polyolefin film, polyimide film, polyamideimide film, polyphenylene sulfide film, polyethylene naphthalate film, liquid crystal polymer (LCP) film, and polycycloolefin film. Insulating resin coating layers include styrene resins, vinyl acetate resins, polyester resins, polyolefin resins such as polyethylene and polypropylene, amide resins, amideimide resins, styrene-butadiene resins, acrylonitrile-butadiene resins, and (meth) acryl-butadiene resins. UV rays composed of thermoplastic resins such as (meth) acrylic resin and urethane resin, thermosetting resins such as phenolic resin, epoxy resin, melamine resin and alkyd resin, urethane-acrylate, epoxy-acrylate, acrylic-acrylate, etc. A curable resin or the like can be used alone or in combination of two or more. Among these, in consideration of harsh thermal conditions (for example, during solder reflow) when manufacturing an electronic device on which a printed wiring board is mounted, a thermosetting resin or an ultraviolet curable resin is preferable, and an epoxy resin, a urethane resin, It is preferable to use a polyester resin, a melamine resin, an acrylic resin, urethane-acrylate, epoxy acrylate, acrylic-acrylate, etc. alone, in combination of two or more, or in combination with a crosslinking agent. Moreover, when using as a flexible shield printed wiring board, it is preferable that urethane resin is included.

As a method for producing the shield film of the present invention, for example, a conductive ink is formed directly on the second insulating protective layer or after the polymer layer (B) is formed on the second insulating protective layer. An opening pattern having an opening ratio of 40 to 95% and an opening inner pattern of 15 to 95% of the opening area are formed in the opening of the opening pattern, and electrolytic copper plating is applied only on the opening pattern. The method of forming a copper plating layer and forming a conductive adhesive layer on it is mentioned.

Further, on the second insulating protective layer or on the polymer layer (B) provided on the second insulating protective layer, an opening pattern having an opening ratio of 40 to 90% and an opening inside the opening pattern are formed with conductive ink. A pattern of 15 to 95% of the opening area is formed, and a copper plating layer is formed by applying electroless plating on the opening pattern and the pattern formed inside the opening, and then electrolytic copper is formed only on the opening pattern. There is also a method of forming a copper plating layer by plating and forming a conductive adhesive layer thereon.

As a method of forming an opening pattern with an opening ratio of 40 to 95% and a pattern with an opening area of 15 to 95% inside the opening of the opening pattern,
(1) After forming an opening pattern using a conductive ink, electrolytic copper plating is applied to the opening pattern to form a copper plating layer, and then the opening pattern is formed with a conductive ink inside the opening pattern. A method of forming a 95% opening internal pattern, (2) a method of simultaneously forming an opening pattern and an opening internal pattern using a conductive ink, and performing electrolytic copper plating only on the opening pattern to form a copper plating layer; In particular, the method (2) of simultaneously forming the opening pattern and the opening inner pattern is preferable because of excellent production efficiency. In the case of the method (2), since it is necessary to apply electrolytic copper plating only to the opening pattern, in order to use only the opening pattern as a conductive layer for electrolytic copper plating, the opening pattern and the opening inner pattern are not contacted. Preferably there is. In the method (2), after forming the opening pattern and the opening inner pattern, after thickening both the opening pattern and the opening inner pattern by an electroless plating method, electrolytic copper plating is applied only to the opening pattern portion. It can also implement by the method of giving and forming a copper plating layer. Even in this case, it is preferable that the opening pattern and the opening inner pattern are non-contact. The formation method of the polymer layer (B), the layer (A-1) and the layer (A-2) is as described above.

As described above, the second insulating protective layer can be an insulating resin sheet or film, or an insulating resin coating layer. However, when the second insulating protective layer is manufactured by coating the insulating resin, it is supported. A release film can be used as the substrate.

As the release film, a plastic film or release paper can be used. Examples of the plastic film include a polyester film, a polyolefin film, a polyimide film, and a film in which a silicone release layer, a fluorine release layer, an olefin release layer, and the like are further provided on these films. It is done. Examples of the release paper include those in which a sealing layer is provided on a paper substrate and then a silicone release layer, a fluorine release layer, and an olefin release layer are provided thereon.

As said 2nd insulation protective layer formed by coating, what coated resin etc. which were illustrated above can be used, for example, an insulating resin is applied to the said peeling film, it is dried, and resin is needed as needed. Can be cured by heat curing and ultraviolet curing to produce the second insulating protective layer.

In the shield film manufacturing method of the present invention, a conductive adhesive layer is formed on the copper plating layer. As the conductive adhesive layer, specifically, those described above can be used. The conductive adhesive layer can be formed by applying the conductive adhesive on the copper plating layer pattern and drying it as necessary. The shield film obtained in this manner can be used as a shield film that is attached to the outermost surface of the shield printed wiring board of the present invention.

The manufacturing method of the shield printed wiring board of the present invention will be described. The printed wiring board constituting the shield printed wiring board of the present invention is formed with signal wiring and ground wiring on a printed wiring board substrate, and a first insulating protective layer is provided thereon, and the first insulating protective layer is A ground wire having a partly exposed via is used. When the shield printed wiring board of the present invention is a flexible printed wiring board (FPC), a single-sided FPC having a printed circuit only on one side of the base film, and a double-sided FPC having a printed circuit on both sides of the base film Multi-layer FPC in which a plurality of such FPCs are laminated, Flexboard (registered trademark) having a multilayer component mounting portion and a cable portion, a flex rigid board having a rigid member constituting the multilayer portion, or a tape carrier A TAB tape or the like for the package can be adopted as appropriate.

On the first insulating protective layer of the printed wiring board, the conductive adhesive layer of the shield film of the present invention is disposed so as to be in contact, and the printed wiring board and the shield film are shielded by pressing in a direction approaching each other. The shield printed wiring board of the present invention can be manufactured by flowing the conductive adhesive layer of the film and connecting it to the ground layer of the printed wiring board. When the printed wiring board and the shield film are pressurized to cause the conductive adhesive layer to flow and join with the ground layer of the printed wiring board, it can be heated, and the conductive adhesive can be thermoset. In the case of containing a resin, the heating conditions can be adjusted according to the curing conditions of the resin. The heating temperature is usually preferably in the range of 50 to 250 ° C.

The shield printed wiring board of the present invention may have a configuration in which a shield film is attached to one side of the printed wiring board or a configuration in which shield films are attached to both sides.

Hereinafter, the present invention will be described in detail by way of examples.

[Preparation of conductive ink (1)]
By dispersing silver particles having an average particle diameter of 20 nm in a mixed solvent of 35 parts by mass of ethylene glycol and 65 parts by mass of ion-exchanged water, using a compound in which polyoxyethylene is added to polyethyleneimine as a dispersant, metal nanoparticles are dispersed. A metal nanoparticle dispersion containing particles and a polymer dispersant having a basic nitrogen atom-containing group as a reactive functional group was prepared. Next, ion-exchanged water and a surfactant were added to the obtained metal nanoparticle dispersion, and the viscosity was adjusted to 11 mPa · s to prepare a conductive ink (1) for inkjet printing.

[Manufacture of resin for second insulating protective layer]
100 parts by mass of polyester polyol (polyester obtained by reacting 1,4-cyclohexanedimethanol, neopentyl glycol and adipic acid in a nitrogen-substituted container equipped with a thermometer, nitrogen gas inlet tube and stirrer Polyol, a hydroxyl group equivalent of 1,000 g / equivalent), 17.4 parts by mass of 2,2-dimethylolpropionic acid, 21.7 parts by mass of 1,4-cyclohexanedimethanol, and 106.2 parts by mass of dicyclohexylmethane diisocyanate. By mixing and reacting in 178 parts by mass, an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular end was obtained.

Next, 13.3 parts by mass of triethylamine was added to the organic solvent solution of the urethane prepolymer obtained above to neutralize part or all of the carboxyl groups of the urethane resin, and 277 parts by mass of water was further added. By sufficiently stirring, an aqueous dispersion of urethane resin having a carboxyl group was obtained.

By adding 8 parts by mass of a 25% by mass ethylenediamine aqueous solution to the aqueous dispersion of the urethane resin obtained above and stirring, the urethane resin is chain-extended, and then aging / desolvent to obtain a solid content of 30% by mass. % Aqueous dispersion of urethane resin was obtained. Next, 30 parts by mass of sorbitol polyglycidyl ether (epoxy equivalent 170) was added to 333 parts by mass of the obtained aqueous dispersion of urethane resin and mixed to obtain a resin solution for the second insulating protective layer.

[Manufacture of polymer layer (B-1) resin]
Into a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping the monomer mixture and dropping funnel for dropping the polymerization catalyst, 180 parts by mass of ethyl acetate was added and the temperature was increased to 80 ° C. while blowing nitrogen. The temperature rose. In a reaction vessel heated to 80 ° C., with stirring, a vinyl monomer mixture containing 60 parts by mass of methyl methacrylate, 10 parts by mass of n-butyl acrylate and 30 parts by mass of glycidyl methacrylate, and azoisobutyro A polymerization initiator solution containing 1 part by mass of nitrile and 20 parts by mass of ethyl acetate was dropped and polymerized from another dropping funnel over 240 minutes while maintaining the temperature in the reaction vessel at 80 ± 1 ° C. After completion of the dropwise addition, the mixture was stirred at the same temperature for 120 minutes, and then the temperature in the reaction vessel was cooled to 30 ° C., and then ethyl acetate was added so that the nonvolatile content was 10% by mass to obtain a reactive functional group. A resin for the polymer layer (B-1) containing an epoxy group was obtained.

[Manufacture of resin for polymer layer (B-2)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, polycarbonate polyol (polycarbonate diol having an acid group equivalent of 1000 g / equivalent obtained by reacting 1,4-cyclohexanedimethanol and carbonate ester) is added. 100 parts by weight, 9.7 parts by weight of 2,2-dimethylolpropionic acid, 5.5 parts by weight of 1,4-cyclohexanedimethanol, and 51.4 parts by weight of dicyclohexylmethane diisocyanate in a mixed solvent of 111 parts by weight of methyl ethyl ketone By making it react, the organic solvent solution of the urethane prepolymer which has an isocyanate group in the molecular terminal was obtained.

Next, 7.3 parts by mass of triethylamine is added to the organic solvent solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and 355 parts by mass of water is further added and sufficiently stirred. Thus, an aqueous dispersion of urethane resin was obtained.

Next, 4.3 parts by mass of a 25% by mass ethylenediamine aqueous solution is added to the aqueous dispersion, and the particulate polyurethane resin is chain-extended by stirring, followed by aging / desolving, so that the solid content concentration is 30. An aqueous dispersion of mass% urethane resin was obtained.

140 parts by mass of deionized water in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping the monomer mixture, dropping funnel for dropping the polymerization catalyst, water dispersion of the urethane resin obtained above 100 parts by mass of the liquid was added, and the temperature was raised to 80 ° C. while blowing nitrogen. In a reaction vessel heated to 80 ° C., a monomer mixture containing 60 parts by mass of methyl methacrylate, 30 parts by mass of n-butyl acrylate, and 10 parts by mass of Nn-butoxymethylacrylamide with stirring was added. 20 parts by mass of an aqueous ammonium sulfate solution (concentration: 0.5% by mass) was dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization.

After completion of the dropwise addition, the mixture was stirred for 60 minutes at the same temperature, then the temperature in the reaction vessel was cooled to 40 ° C., and deionized water was added so that the nonvolatile content was 20% by mass, and then 200 mesh. By filtering with a filter cloth, a polymer layer (B-2) resin containing a carboxyl group and an Nn-butoxymethylacrylamide group as a reactive functional group was obtained.

[Manufacture of resin for conductive adhesive]
100 parts by mass of polyester polyol (polyester obtained by reacting 1,4-cyclohexanedimethanol, neopentyl glycol and adipic acid in a nitrogen-substituted container equipped with a thermometer, nitrogen gas inlet tube and stirrer Polyol, hydroxyl group equivalent 1000 g / equivalent), 17.4 parts by mass of 2,2-dimethylolpropionic acid, 21.7 parts by mass of 1,4-cyclohexanedimethanol and 106.2 parts by mass of dicyclohexylmethane diisocyanate, and 178 parts by mass of methyl ethyl ketone. By mixing and reacting in the part, a urethane resin having an isocyanate group at the molecular end was obtained. Subsequently, methyl ethyl ketone was added to the obtained urethane resin to obtain an organic solvent solution of a urethane resin having a solid content of 50% by mass.

[Preparation of conductive adhesive]
To 200 parts by mass of the organic resin solution of urethane resin obtained above, 20 parts by mass of bisphenol A type epoxy resin (epoxy equivalent 180) is added and mixed, and further, a silver filler (“S— 201 ") 80 parts by mass was added and mixed to prepare a conductive adhesive.

(Example 1)
As a printed wiring board, a wiring composed of a copper wiring pattern for ground having a copper thickness of 12 μm and a line width of 500 μm and a signal copper wiring pattern having a copper thickness of 12 μm and a line width of 150 μm is formed on a polyimide base film. The first insulating protective layer having a film thickness of 27.5 μm is formed of an adhesive layer having a film thickness of 15 μm and a polyimide film layer having a film thickness of 12.5 μm. A printed wiring board having a 400 μm square opening in the ground wiring portion was used.

As a shield film, on the release-treated polyester film, the second insulating protective layer resin produced above is applied so that the film thickness after drying is 5 μm, and dried to form a second insulating protective layer. Formed. Next, the polymer layer (B-1) resin produced above was applied so that the film thickness after drying was 0.2 μm, and dried to form a polymer layer (B-1).

Next, the conductive ink (1) obtained above is applied onto the second insulating protective layer on which the polymer layer (B-1) formed by the above method is laminated, by an inkjet printer (inkjet manufactured by Konica Minolta Co., Ltd.). Using a test machine “EB100”, an evaluation printer head KM512L, and a discharge amount of 14 pL), a lattice pattern having a line width of 90 μm and an aperture ratio of 82% is formed in the opening so that the characteristic impedance of the shield printed wiring board is 80Ω. A square non-opening portion having an area of 68% with respect to the area of the opening portion was printed so as not to contact the lattice pattern portion. A plan view of the printed pattern is shown in FIG. Next, by baking at 120 ° C. for 20 minutes, a layer (film thickness 0.2 μm) made of a conductive ink (1) having a lattice pattern with an aperture ratio of 82% and a square non-opening inside the opening is formed. did.

Next, the lattice pattern portion of the layer made of the conductive ink (1) obtained above is set as the cathode, the phosphorous copper is set as the anode, and the current density is 2 A using an electrolytic plating solution containing copper sulfate. By performing electrolytic copper plating at / dm ² for 10 minutes, a copper plating layer having a thickness of 5 μm was laminated only on the lattice pattern portion on the surface of the layer made of conductive ink. As the copper electroplating solution, 70 g / liter of copper sulfate, 200 g / liter of sulfuric acid, 50 mg / liter of chloride ions, and 5 ml / liter of additives (“Top Lucina SF-M” manufactured by Okuno Pharmaceutical Co., Ltd.) were used. The line width of the lattice pattern portion after electrolytic copper plating was 100 μm, the aperture ratio was 80%, and the area of the layer made of conductive ink (opening internal pattern) inside the opening was 71% of the opening area.

Next, on the entire surface including the copper plating layer of the lattice pattern with an aperture ratio of 80% formed on the second insulating protective layer obtained above and the conductive ink pattern of the non-opening portion inside the opening, the above-mentioned The conductive adhesive produced in (1) was applied to a film thickness of 5 μm after drying, and dried to produce a shield film.

Next, the printed wiring board obtained by opening the ground wiring part obtained above and the shielding film obtained above are formed on the insulating protective layer of the printed wiring board, and the conductive adhesive layer of the shielding film. The printed wiring board and the shield film are pressed in a direction approaching each other (pressure: 1.96 MPa, heating temperature: 150 ° C., treatment time: 30 minutes), and the shield film is conductive. The conductive adhesive layer was allowed to flow and connected to the ground layer of the printed wiring board to produce a shield printed wiring board.

(Examples 2 to 4)
Instead of the printed wiring board used in Example 1, the signal copper wiring pattern width shown in Table 1 was used. Further, in place of the shield film used in Example 1, the polymer layer (B) resin shown in Table 1 was used, and the copper shown in Table 1 so that the characteristic impedance of the shield printed wiring board was 80Ω. A shield printed wiring board was produced in the same manner as in Example 1 except that the aperture ratio of the plating layer and the area ratio of the conductive ink layer (opening internal pattern) inside the opening to the opening area of the copper plating layer.

(Example 5)
Instead of the printed wiring board used in Example 1, the signal copper wiring pattern width shown in Table 1 was used. As a shield film, on the release-treated polyester film, the second insulating protective layer resin produced above is applied so that the film thickness after drying is 5 μm, and dried to form a second insulating protective layer. Formed. Next, on the second insulating protective layer formed by the above method, the conductive ink (1) is used in the same manner as in Example 1, and the line width is adjusted so that the characteristic impedance of the shield printed wiring board is 80Ω. A grid pattern having a size of 90 μm and an aperture ratio of 58% and a rectangular non-opening with an area of 40% with respect to the area of the opening inside the opening were printed so as not to contact the grid pattern. Next, by baking at 120 ° C. for 20 minutes, a layer (film thickness 0.2 μm) made of a conductive ink (1) having a lattice pattern with an aperture ratio of 58% and a square non-opening inside the opening is formed. did.

Next, the lattice pattern portion of the layer made of the conductive ink (1) obtained above was set as the cathode, the phosphorous copper was set as the anode, and the layer made of the conductive ink was set in the same manner as in Example 1. On the surface, a copper plating layer having a thickness of 5 μm was laminated only on the lattice pattern portion. The line width of the lattice pattern portion after electrolytic copper plating was 100 μm, the aperture ratio was 56%, and the area of the layer made of conductive ink (opening internal pattern) inside the opening was 43% of the opening area.

Next, on the entire surface including the copper plating layer with a lattice pattern of 56% opening ratio formed on the second insulating protective layer obtained above and the conductive ink pattern of the non-opening portion inside the opening, the above-mentioned The conductive adhesive produced in (1) was applied to a film thickness of 5 μm after drying, and dried to produce a shield film.

Next, the printed wiring board provided with an opening in the ground wiring portion and the shield film obtained above were pressure-bonded onto the insulating protective layer of the printed wiring board in the same manner as in Example 1, The conductive adhesive layer was allowed to flow and connected to the ground layer of the printed wiring board to produce a shield printed wiring board.

(Example 6)
Instead of the printed wiring board used in Example 1, the signal copper wiring pattern width shown in Table 1 was used. Further, in place of the shield film used in Example 1, the polymer layer (B) resin shown in Table 1 was used. Next, on the second insulating protective layer on which the polymer layer (B-1) formed by the above method is laminated, the conductive ink (1) is used in the same apparatus as in Example 1, and the shield printed wiring board is used. A lattice pattern having a line width of 90 μm and an aperture ratio of 74%, and a square non-opening with an area of 69% of the area of the opening inside the opening, Printed out of contact. Next, by baking at 120 ° C. for 20 minutes, a layer (film thickness 0.05 μm) made of a conductive ink (1) having a lattice pattern with an aperture ratio of 74% and a square non-opening inside the opening is formed. did.

Next, electroless copper plating is performed on the layer (thickness 0.05 μm) made of the conductive ink (1) having a rectangular non-opening inside the lattice pattern obtained above, and the thickness An electroless copper plating film having a thickness of 0.2 μm was formed. For electroless copper plating, ARG Copper (Okuno Pharmaceutical Co., Ltd.) is built under standard recommended conditions (ARG Copper 1:30 ml / L, ARG Copper 2: 15 ml / L, ARG Copper 3: 200 ml / L). This was performed by bathing and holding at a bath temperature of 45 ° C., and immersing the object to be plated (conductive ink layer) in this for 15 minutes to precipitate a copper plating film.

Next, the lattice pattern part in which the electroless copper plating film was formed on the layer made of the conductive ink (1) obtained above was set as the cathode, and phosphorous copper was set as the anode. A copper plating film having a thickness of 3 μm was laminated only on the lattice pattern portion on the surface of the layer made of the electroless copper plating film. The line width of the lattice pattern portion after electrolytic copper plating is 97 μm, the aperture ratio is 72%, the area of the layer made of electroless copper plating film inside the opening (opening internal pattern) is 70% of the opening area, and the film thickness is It was 0.2 μm.

Next, the entire surface including the copper plating layer having a lattice pattern of 72% formed on the second insulating protective layer obtained as described above and the electroless copper plating film in the non-opening portion inside the opening. On top, the conductive adhesive produced above was applied so as to have a film thickness of 5 μm after drying, and dried to produce a shield film.

(Comparative Example 1)
Instead of the printed wiring board used in Example 1, a printed wiring board having a line width of the signal copper wiring pattern described in Table 1 was used. In addition, instead of the shield film used in Example 1, the film thickness after drying the resin for the second insulating protective layer obtained above on a rolled copper foil having a film thickness of 5 μm so that the aperture ratio becomes 0%. Was applied to a thickness of 5 μm and dried to form a second insulating protective layer. Next, the surface of the rolled copper foil opposite to the surface on which the second insulating protective layer is formed is coated with the conductive adhesive obtained above so as to have a film thickness after drying of 5 μm, and dried to obtain an aperture ratio. A shield film having a 0% copper layer was prepared.

Next, the line width of the signal copper wiring pattern described in Table 1 is used, and the printed wiring board having a 400 μm square opening in the ground wiring part and the shield film obtained above are insulated from the printed wiring board. It arrange | positions so that the conductive adhesive layer of a shield film may contact | connect on a protective layer, and a printed wiring board and a shield film are pressurized in the direction which mutually approaches (pressure: 1.96 MPa, heating temperature: 150 degreeC, process (Time: 30 minutes) and pressure-bonded, and the conductive adhesive layer of the shield film was flowed to be connected to the ground layer of the printed wiring board to produce a shield printed wiring board.

(Comparative Example 2)
Instead of the printed wiring board used in Comparative Example 1, the line width of the signal copper wiring pattern was changed to the line width described in Table 1, and the comparative example with an aperture ratio of 0% was made in the same manner as in Comparative Example 1. A shield printed wiring board was produced.

[Manufacture of Resin for Conductive Ink (R1) for Comparison]
The number average molecular weight obtained from adipic acid, terephthalic acid, and 3-methyl-1,5-pentanediol is 1006 in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube. A diol (414 parts by mass), dimethylolbutanoic acid (8 parts by mass), isophorone diisocyanate (145 parts by mass) and toluene (40 parts by mass) were charged and reacted at 90 ° C. for 3 hours in a nitrogen atmosphere. Next, 300 parts by mass of toluene was further added to the reaction solution to obtain a urethane prepolymer solution having an isocyanate group at the terminal.

Next, 816 parts by mass of the urethane prepolymer solution obtained above was added to a mixture of 27 parts by mass of isophoronediamine, 3 parts by mass of di-n-butylamine, 342 parts by mass of 2-propanol and 576 parts by mass of toluene. And reacted at 70 ° C. for 3 hours to obtain a polyurethane polyurea resin solution. To this, 144 parts by mass of toluene and 72 parts by mass of 2-propanol were added to obtain a resin solution for a conductive ink (R1) for comparison having a solid content of 30% by mass of the polyurethane polyurea resin.

[Preparation of Comparative Conductive Ink (R1)]
333 parts by mass of the resin solution for conductive ink for comparison obtained above and 20 parts by mass of bisphenol A type epoxy resin (“JER828” manufactured by Mitsubishi Chemical Corporation) were stirred and mixed to obtain a resin composition solution. To 353 parts by mass of this resin composition solution, 180 parts by mass of a conductive filler (“AgXF-301” manufactured by Fukuda Metal Foil Powder Co., Ltd.) is added and mixed by stirring to a total of 100 parts by mass of the polyurethane polyurea resin and the epoxy resin. In contrast, a comparative conductive ink (R1) containing 300 parts by mass of a conductive filler was obtained.

[Manufacture of resin for bonding layers]
20 parts by mass of a bisphenol A type epoxy resin was added to 333 parts by mass of the polyurethane polyurea resin solution produced in the same manner as the resin for the conductive ink (R1) to obtain a resin for a bonding layer.

(Comparative Example 3)
As a shield film, a comparative conductive ink (R1) obtained as described above is formed on a release-treated polyester film by using a grid having a line width of 100 μm, an aperture ratio of 65%, and a film thickness after drying of 5 μm. It screen-printed so that it might become a pattern, and it dried and formed the conductive layer. Next, the resin for bonding layer obtained above was applied on the release-treated polyester film so that the film thickness after drying was 15 μm and dried. Next, the conductive layer formed on the releasable film and the bonding layer formed on the releasable film were bonded together to produce a shield film.

Next, instead of the printed wiring board used in Example 1, the wiring width of the signal copper wiring pattern is set to 100 μm, and a 400 μm square opening is provided in the ground wiring portion. The shield film was placed on the insulating protective layer of the printed wiring board so that the conductive layer of the shield film was in contact, and the printed wiring board and the shield film were pressurized in a direction approaching each other (pressure: 1.96 MPa). , Heating temperature: 150 ° C., processing time: 30 minutes), and the shielded printed wiring board for comparison without the conductive adhesive layer, which is bonded to the ground layer of the printed wiring board by flowing the bonding layer of the shield film and flowing. Was made.

[Measurement of electromagnetic shielding properties (transmission attenuation rate)]
The shielded printed wiring boards obtained in the above examples and comparative examples are irradiated with electromagnetic waves under the conditions of 100 MHz to 6 GHz using a coaxial tube type shield effect measuring system in accordance with ASTM D4935 and subjected to electromagnetic waves. Was measured by the shielding film, and the electromagnetic shielding properties were evaluated according to the following criteria. Note that the measured value of attenuation is expressed in decibels (unit dB). In general, the electromagnetic wave shielding property is good as long as it is 40 dB (or more than 99% of electromagnetic waves are blocked).
A: 45 dB or more when irradiated with 6 GHz electromagnetic waves in the microwave region.
B: 40 dB or more and less than 45 dB when irradiated with 6 GHz electromagnetic waves.
C: 35 dB or more and less than 40 dB when irradiated with 6 GHz electromagnetic waves.
D: Less than 35 dB when irradiated with 6 GHz electromagnetic waves.

[Measurement of characteristic impedance]
About the shield printed wiring board obtained by said Example and comparative example, characteristic impedance was measured using network analyzer E5071C (made by Agilent Technologies).

[Evaluation of connection reliability between shield film and printed circuit board ground wiring]
For the shield printed wiring boards obtained in the above examples and comparative examples, a solder reflow process at the time of component connection is assumed, and the shield printed wiring board is cooled to 25 ° C. after passing through a reflow furnace at 240 ° C. for 25 seconds. Repeat the reflow operation 5 times, measure the volume resistance value between the shield film before and after that and the ground wiring of the printed wiring board, calculate the rate of change of the volume resistance value using the following formula, and shield film and printed wiring The connection reliability of the plate with the ground wiring was evaluated according to the following criteria.
[Evaluation criteria]
A: The rate of change of the volume resistance value is less than 20%.
B: The rate of change of the volume resistance value is 20% or more and less than 50%.
C: The change rate of the volume resistance value is 50% or more and less than 80%.
D: The change rate of the volume resistance value is 80% or more.

Table 1 summarizes the results evaluated above.

From the results shown in Table 1 above, in the shield printed wiring boards of Examples 1 to 5 using the shield film of the present invention, the pattern width of the signal copper wiring of the printed wiring board was changed to 50 to 150 μm. The characteristic impedance of the shield printed wiring board could be controlled to 80Ω by adjusting the aperture ratio of the metal layer (copper plating layer) of the shield film. Further, the electromagnetic wave shielding property was 45 dB or more, and it was confirmed that the electromagnetic wave shielding property was also excellent.

In addition, the film thickness of the shield film portions of Examples 1 to 6 which are the shield films of the present invention is as thin as 13 to 16 μm in total thickness of the second insulating layer, the copper plating layer, and the conductive adhesive layer. Compared to a shield film that requires two layers of an open metal layer and a non-open metal layer (shield layer) described in Document 3, the shield film has a feature that the film thickness of the shield film can be further reduced.

On the other hand, in the shield printed wiring board of Comparative Example 1, the pattern width of the signal copper wiring of the printed wiring board is 150 μm, and the aperture ratio of the metal layer (copper plating layer) of the shield film is 0% (entire copper plating layer). This is an example. The characteristic impedance of this shield printed wiring board was 20Ω and could not be controlled to 80Ω.

In the shield printed wiring board of Comparative Example 2, the aperture ratio of the metal layer (copper plating layer) of the shield film was set to 0% (entire copper plating layer) as in Comparative Example 1, and the pattern of the signal copper wiring on the printed wiring board Even when the width was 20 μm, the characteristic impedance was 50Ω. Furthermore, this shielded printed wiring board has a transmission loss that increases as the communication speed becomes higher compared to the shielded printed wiring board of the embodiment, by reducing the pattern width of the signal copper wiring of the printed wiring board to 20 μm. There was an increasing problem.

From the above results, the shield printed wiring board of the present invention has the desired characteristics by adjusting the opening ratio of the metal layer of the shield film even when the pattern width of the signal copper wiring of the printed wiring board is changed. It was possible to adjust the impedance, and it was confirmed that the electromagnetic wave shielding property was high.

Further, the shield printed wiring board of Comparative Example 3 is an example in which there is no essential conductive adhesive layer in the shield printed wiring board of the present invention. This shielded printed wiring board has insufficient electromagnetic wave shielding properties, and has a problem in connection reliability between the conductive layer on the shield film side and the ground wiring on the printed wiring side.

DESCRIPTION OF SYMBOLS 1 .... Shield film 2 .... 2nd insulation protective layer 2 '... Polymer layer 3 .... Layer formed using conductive ink 3' ... Using conductive ink Copper plating layer formed on the formed layer 4... Copper plating layer having openings 5... Conductive adhesive layer 6... First insulation protective layer 7. Plate base material 8... Signal wiring 9... Ground wiring 10... First insulation protective layer removal portion (conduction portion between ground wiring and copper plating layer having opening)
11 ... Printed wiring board 12 ... Shield printed wiring board

Claims

A shield film for a printed wiring board in which a signal wiring, a ground wiring, and a first insulating protective layer are provided on a base insulating base material,
A conductive adhesive layer laminated on the entire surface of the first insulating protective layer;
A copper plating layer patterned with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95% on the conductive adhesive layer;
A layer (A-1) formed using a conductive ink on the copper plating layer;
A layer (A-2) formed using a conductive ink inside the opening of the copper plating layer on the conductive adhesive layer;
A shielding film comprising a second insulating protective layer on the conductive adhesive layer, the copper plating layer, the layer (A-1) and the layer (A-2).
The shield film according to claim 1, further comprising a copper plating layer between the conductive adhesive layer and the layer (A-2).
3. The shield film according to claim 1, wherein the area of the layer (A-2) is 15 to 95% of the opening area of the copper plating layer and the film thickness is 0.02 to 2 μm.
The shield film according to any one of claims 1 to 3, wherein the conductive ink is an ink mainly composed of metal nanoparticles as a conductive substance (a2).
The shield film according to claim 4, wherein the metal nanoparticles are dispersed by a polymer dispersant.
The polymer layer (B) is provided between the second insulating protective layer and the layer (A-1) and the layer (A-2) formed using the conductive ink. The shield film of any one of Claims.
The conductive ink is a conductive ink containing a compound (a1) having a reactive functional group [X] and a conductive substance (a2),
And the polymer layer (B) is a layer composed of a polymer containing the compound (b1) having a reactive functional group [Y],
The reactive functional group [X] of the compound (a1) contained in the conductive ink reacts with the reactive functional group [Y] of the compound (b1) contained in the polymer layer (B). The shield film according to claim 6, wherein a bond is formed by forming the bond.
The shield film according to claim 7, wherein the conductive ink is a conductive ink containing a compound (a1) having a basic nitrogen atom-containing group as a reactive functional group [X] and a conductive substance (a2).
The shield film according to claim 8, wherein the compound (a1) having a basic nitrogen atom-containing group is a polyalkyleneimine or a polyalkyleneimine having a polyoxyalkylene structure containing an oxyethylene unit.
The reactive functional group [Y] is at least one selected from the group consisting of a keto group, an epoxy group, a carboxyl group, an N-alkylol group, an isocyanate group, a vinyl group, a (meth) acryloyl group, and an allyl group. The shield film according to any one of claims 7 to 9.
A shield printed wiring board comprising the shield film according to any one of claims 1 to 10.
On the second insulating protective layer or the polymer layer (B) provided on the second insulating protective layer,
An opening pattern having an opening ratio of 40 to 90% and a pattern of 15 to 95% of the opening area are formed inside the opening of the opening pattern with conductive ink,
Electrolytic copper plating is performed on the opening pattern to form a copper plating layer,
A method for producing a shield film, comprising forming a conductive adhesive layer thereon.
On the second insulating protective layer or the polymer layer (B) provided on the second insulating protective layer,
An opening pattern having an opening ratio of 40 to 90% and a pattern of 15 to 95% of the opening area are formed inside the opening of the opening pattern with conductive ink,
Electroless plating is performed on the opening pattern and the pattern formed inside the opening to form a copper plating layer,
Next, electrolytic copper plating is performed only on the opening pattern to form a copper plating layer,
A method for producing a shield film, comprising forming a conductive adhesive layer thereon.
As the conductive ink (A), an ink mainly composed of metal nanoparticles is used, and an opening pattern with an opening ratio of 40 to 90% by ink jet printing and a pattern with an opening area of 15 to 95% inside the opening of the opening pattern. The manufacturing method of the shield film of Claim 12 or 13 which forms.
A signal wiring, a ground wiring and an insulating protective layer are provided, and the insulating protective layer is a printed wiring board having a via in which a part of the ground wiring is exposed,
A shield film according to any one of claims 1 to 10 is disposed on an insulating protective layer of a printed wiring board so that a conductive adhesive layer is in contact with the insulating protective layer of the printed wiring board. A method for producing a shielded printed wiring board, wherein the conductive adhesive layer of the shield film is caused to flow by pressurizing the board and the shield film toward each other to be connected to the ground layer of the printed wiring board.