TW201626865A - Shield film, shield printed wiring board, and methods for manufacturing shield film and shield printed wiring board - Google Patents

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 [mu]m 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

Shielding film, shielded printed circuit board, and the like

The present invention relates to a shielding film for a printed circuit board, a shielded printed circuit board using the same, and the like.

[In recent years, regarding the electronic equipment, the high-speed transmission specifications required for USB 3.0, IEEE 1394, and HDMI (registered trademark) are rapidly changing, and high-speed serial communication is often used. Moreover, in most machines, the transmission mode in the machine is also transmitted as one of the active transmissions (LVDS (Low Voltage Differential Signal)), and impedance matching between the interfaces of the machine becomes important. Recently, the industry has demanded higher signal transmission. If the impedance at the interface between the devices is mismatched, there is a problem that reflection occurs at the transmission path, and waveform distortion occurs due to the overlap of the signal wave and the reflected wave, and the signal transmission loss becomes large. In particular, if the frequency used is high, the influence of the reflected wave due to the impedance mismatch becomes large. Therefore, for a printed circuit board used at a high frequency, it is necessary to control the impedance and the other substrate or component to be connected to the impedance. Used in the state of matching.

[Also, with the miniaturization of electronic equipment, the demand for thinning of printed circuit boards has become high. When the printed circuit board is made thinner, the distance between the signal line and the ground layer becomes closer, and the capacity component of the signal line increases. In order to maintain the same impedance, the line width (pattern width) of the signal line must be made thinner to reduce the capacitance component. However, if the pattern width of the signal line is thinned, there is a problem that the resistance loss increases and the DC resistance increases. Therefore, it is required to control the impedance while maintaining a constant pattern width.

On the other hand, with the high performance of electronic devices, the noise countermeasures inside the machine are also Become important. In order to reduce the influence of the signal transmission path of the printed circuit board and the noise generated by itself on other parts, and from the noise generated by other parts, the shielding is studied. As a method of shielding, for example, a shield printed circuit board having a structure in which a conductive circuit having a high conductivity and electromagnetic waves is provided on a cover layer of a signal circuit is provided in a printed circuit board having a signal circuit and a ground circuit on an insulating substrate. The metal thin film layer having a high shielding effect is used as a shielding material, and the grounding circuit of the printed circuit board and the metal thin film layer are electrically connected via a conductive adhesive (see, for example, Patent Document 1).

However, although the above-mentioned shielded printed circuit board can solve the problem of noise countermeasures inside the machine, the method of controlling the impedance of the printed circuit board to match the impedance of other connected devices is only by making the signal circuit Thinning of the pattern width does not solve the problem, and there is a problem that the degree of freedom of the pattern of the signal circuit is limited.

Moreover, as an electromagnetic wave shielding sheet used for a circuit board having a signal circuit, there has been proposed an electromagnetic wave shielding sheet having a bonding layer and a conductive layer containing a thermosetting resin having a glass transition temperature of 0 to 150 ° C. The composition is flowable and insulating under the conditions of a temperature of 150 ° C and a pressure of 1 kg/cm ² , and the conductive layer is provided on one surface of the bonding layer and has a plurality of openings (see, for example, Patent Document 2). In the electromagnetic wave shielding sheet, an opening is provided in the conductive layer, and is directly connected to a ground circuit of the printed circuit board through a through hole provided in the printed circuit board, thereby adjusting the impedance of the printed circuit board.

However, in the printed circuit board using the above-described electromagnetic wave shielding sheet, although the impedance can be adjusted by appropriately setting the shape and the aperture ratio of the opening portion of the electromagnetic wave shielding sheet, when the aperture ratio is set to be higher than 40%, There is a problem that the electromagnetic wave shielding performance is greatly reduced.

Further, in the printed circuit board using the electromagnetic wave shielding sheet, since the conductive layer of the electromagnetic wave shielding sheet is directly connected to the ground circuit of the printed circuit board, the hardness of the conductive layer and the line width of the pattern are made on the printed circuit board. The size of the through holes to be provided is limited, and the connection reliability is insufficient. For example, shielding electromagnetic waves When the line width of the pattern of the conductive layer of the sheet is set to be thicker than the ground circuit of the printed circuit board, the conductive layer and the ground circuit become difficult to connect, even if it is directly connectable, since the bonding area of the thermosetting resin layer is very large. Small and there is a problem that the connection reliability is insufficient. Further, in the case where the through hole provided in the ground circuit of the printed circuit board is small, the connection reliability is also insufficient. Further, if the insulating protective layer of the printed circuit board is thick, the height of the through hole provided on the grounding circuit is also high, and when the conductive layer of the electromagnetic wave shielding sheet lacks flexibility, there is also a difference in the through hole. And the problem that the conductive layer is broken.

On the other hand, as the impedance control shielding film, an impedance control film including an impedance control film having an open metal layer and having a shielding layer on the surface opposite to the opening metal layer has been proposed (for example, see Patent Document 3). In the impedance control shielding film, the impedance of the printed circuit board is adjusted by the opening metal layer, and the unnecessary radiation which cannot be shielded by the opening metal layer is shielded by the shielding layer which is a non-opening metal layer, so that impedance adjustment and electromagnetic wave shielding can be simultaneously achieved.

However, in the printed circuit board using the above-described impedance control shielding film, since the shielding film must be thickened as a whole in the double layer of the open metal layer and the non-opening metal layer (shield layer), it is difficult to cope with the miniaturization of the electronic device. The problem of thin board requirements.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 7-122882

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2013-168643

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2006-24824

The problem to be solved by the present invention is to provide a printed circuit board that can be used even if A thin shielding film which can control the impedance of the printed circuit board without changing the pattern width of the signal circuit, has high electromagnetic wave shielding properties as a countermeasure against noise, and can further reduce the thickness of the printed circuit board. Further, a shield printed circuit board having excellent connection reliability between the above-mentioned shielding film and a ground circuit of a printed circuit board and a high degree of freedom in design of impedance control is provided. Further, a method of manufacturing the above-described shielding film and shield printed circuit board is provided.

In order to solve the above problems, the inventors of the present invention have diligently studied and found that a conductive adhesive layer and a patterned copper plating are provided on a printed circuit board provided with a signal circuit, a ground circuit, and an insulating protective layer. The shielding film composed of the layer, the patterned conductive ink layer, and the insulating protective layer can control the impedance of the printed circuit board without making the pattern width of the signal circuit thin, and has a countermeasure as a noise countermeasure. A thin shielding film which is highly shielded from electromagnetic waves and which can reduce the thickness of a printed circuit board, and can obtain a shield printed circuit board having excellent connection reliability between the shielding film and the ground circuit of the printed circuit board, and having a high degree of freedom in design of impedance control. Thus, the present invention has been completed.

That is, the present invention relates to a shielding film and a shield printed circuit board having the same, the shielding film characterized in that it is provided with a signal circuit, a ground circuit, and a first insulating protective layer printed on the base insulating substrate. The shielding film for a circuit board has a conductive adhesive layer laminated on the entire surface of the first insulating protective layer, and the conductive adhesive layer is patterned by a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95%. a copper plating layer, a layer (A-1) formed of a conductive ink on the copper plating layer, and a layer formed of a conductive ink inside the opening of the copper plating layer on the conductive adhesive layer ( A-2), and the conductive adhesive layer, the copper plating layer, the layer (A-1), and the second insulating protective layer on the layer (A-2). Further, a method of manufacturing the above-described shielding film and shield printed circuit board.

The shielding film and the shield printed circuit board of the present invention are required for the impedance control of the printed circuit board used at a high frequency, not only by the pattern width of the signal circuit, but also by the aperture ratio of the copper plating layer pattern on the shielding film side. As a factor of impedance control, impedance matching can be achieved while maintaining the degree of freedom of the line width of the signal circuit. Therefore, it can be preferably used as a shielded printed circuit board used inside an electronic device such as a mobile phone, a notebook computer, a smart phone, a tablet terminal, a wearable device, a digital still camera, a digital video camera, or the like.

Further, since the shielding film of the present invention can be made thin, it is possible to cope with the thinning of smart phones and tablet terminals that have been advanced in recent years.

1‧‧‧Shielding film

2‧‧‧Second insulation protection layer

2'‧‧‧ polymer layer

3‧‧‧Layer formed using conductive ink

3'‧‧‧ A copper plating layer formed on a layer formed using a conductive ink

4‧‧‧Copper plating with openings

5‧‧‧ Conductive adhesive layer

6‧‧‧First insulation protection layer

7‧‧‧Printed circuit board substrate

8‧‧‧Signal circuit

9‧‧‧ Grounding circuit

10‧‧‧First insulation protective layer removal part (grounding circuit and conduction part of copper plating layer having an opening)

11‧‧‧Printed circuit board

12‧‧‧Shielded printed circuit board

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a shielded printed circuit board of the present invention.

2 is a cross-sectional view showing a shield printed circuit board of the present invention, in which a polymer layer is provided between a second insulating protective layer and a layer formed using a conductive ink.

3 is a cross-sectional view showing a shield printed circuit board of the present invention, in which a polymer layer is provided between a second insulating protective layer and a layer formed using a conductive ink, and a layer formed using a conductive ink is used. The surface opposite to the surface of the polymer layer is provided with an electroless copper plating layer.

Fig. 4 is a plan view showing a pattern of a copper plating layer and a pattern of a conductive ink layer or an electroless copper plating layer observed from the side of the conductive adhesive layer of the shield printed circuit board of the present invention.

Fig. 5 is a perspective view showing 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 side of the conductive adhesive layer of the shield printed circuit board of the present invention.

Fig. 6 is a plan view showing a pattern printed using a conductive ink when the shield printed circuit board of the present invention is produced in the first embodiment.

The shielding film of the invention is provided with a signal circuit and a grounding electricity on the base insulating substrate. The shielding film for the printed circuit board of the first insulating protective layer and the conductive adhesive layer laminated on the entire surface of the first insulating protective layer and the conductive adhesive layer have a film thickness of 0.5 to 20 μm. a copper plating layer having a patterning ratio of 40 to 95%, a layer (A-1) formed of a conductive ink on the copper plating layer, and an opening inside the copper plating layer on the conductive adhesive layer The layer (A-2) formed of the conductive ink, and the conductive adhesive layer, the copper plating layer, the layer (A-1), and the second insulating protective layer on the layer (A-2) are used.

The base insulating substrate is a substrate of a printed circuit board. Examples of the material of the base insulating base material include a polyester resin such as polyimine, polyamidimide, polyamine or polyethylene terephthalate, and polyethylene naphthalate. Acrylic resin such as polycarbonate, ABS (acrylonitrile-butadiene-styrene) resin or polymethyl methacrylate, fluororesin such as phenol resin or polyvinylidene fluoride, polyvinyl chloride or polyvinylidene chloride Ethylene, polyvinyl alcohol, polyethylene, polypropylene, polyurethane, LCP (liquid crystal polymer), PEEK (polyether ether ketone) resin, PEI (polyether sulfimine) resin, PPS (polyphenyl sulphide) Ether) resin, PSF (polyfluorene) resin, PES (polyether oxime) resin, polyarylate resin, PBT (polybutylene terephthalate) resin, polyoxyn epoxide resin, unsaturated polyester resin, polycondensation Aldehyde, nylon, ceramic, alumina, mullite, talc, magnesium silicate, zirconia, glass, glass epoxy, glass polyimide, phenolic paper, cellulose nanofiber, and the like.

Further, as the base insulating base material, for example, a synthetic fiber including a polyester fiber, a polyamide fiber, an aromatic polyamide fiber, or a natural fiber such as cotton or hemp may be used. The above fibers may also be processed in advance.

As the above-mentioned base insulating base material, in the case where the shield printed wiring board of the present invention described below is used for applications requiring flexibility to bend, it is preferable to use a flexible flexible support. Specifically, it is preferred to use a film or a sheet-like support.

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

Moreover, in order to improve the adhesion to the signal circuit or the ground circuit described below, the base insulating substrate may be subjected to surface unevenness treatment or electrical treatment (corona) by a sandblasting method, a solvent treatment method or the like as needed. Treatment by discharge treatment, atmospheric piezoelectric slurry treatment, chromic acid treatment, flame treatment, hot air treatment, ozone-ultraviolet-electron beam irradiation treatment, oxidation treatment, etc.

In the case where the shape of the base insulating substrate is a film or a sheet, the thickness of the film-like or sheet-like support is usually preferably from about 1 to 5,000 μm, more preferably from about 1 to about 300 μm. In the case where the conductive pattern of the present invention is used for a flexible printed circuit board or the like, it is preferable to use a film having a thickness of about 1 to 200 μm as the insulating base material.

As the base insulating base material, a commercially available copper clad base material can be used in order to form a signal circuit or a ground circuit described below. When a copper-clad substrate is used, a resist material may be provided on the copper-clad substrate, and after the pattern is exposed by the photomask, the copper other than the circuit portion is removed by etching to form a circuit pattern.

Further, as the signal circuit or the ground circuit, the above-described circuit mainly composed of copper may be used, and other conductive materials may be used. For example, a circuit pattern formed by printing a conductive ink mainly composed of silver may be used. Further, it is also possible to form a circuit by thickening a pattern of the conductive ink by copper plating or nickel plating.

The shield printed circuit board of the present invention is provided with a first insulating protective layer on the signal circuit and the ground circuit. The first insulating protective layer may be one in which an adhesive is applied to one surface of a polyimide film or the like, or a photosensitive cover film or the like, and may be formed by exposure and development, or may be coated. A liquid material such as a liquid coating layer, a photosensitive liquid liquid coating layer, or a solder resist is formed to form an insulating protective layer.

Secondly, the shielding film of the present invention is characterized by having: laminating on the first insulation protection a conductive adhesive layer on the entire surface of the layer, a copper plating layer patterned on the conductive adhesive layer with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95%, and a conductive ink is used on the copper plating layer. In the layer (A-1) to be formed, a layer (A-2) formed of a conductive ink and a second insulating protective layer are used inside the opening of the copper plating layer on the conductive adhesive layer.

The conductive adhesive layer includes an adhesive resin containing a conductive material, and examples of the conductive material include metal powders such as copper, silver, nickel, and aluminum, and metal whiskers, and silver plating of copper powder. Silver-coated copper powder, silver-coated nickel powder obtained by silver plating nickel powder, gold-coated nickel powder obtained by gold plating nickel powder, carbon, filler obtained by metal plating of resin particles or glass beads, etc. . These conductive materials may be used alone or in combination of two or more.

Examples of the above-mentioned adhesive resin include a styrene resin, a vinyl acetate resin, a polyester resin, a polyolefin resin such as polyethylene or polypropylene, a guanamine resin, an amidoxime resin, and a styrene-butadiene resin. , thermoplastic resins such as acrylonitrile-butadiene resin, (meth)acrylic acid-butadiene resin, (meth)acrylic resin, urethane resin; phenolic resin, epoxy resin, melamine resin, alcohol A thermosetting resin such as an acid resin; an ultraviolet curable resin such as acrylamide, epoxy acrylate or acryl acrylate. These adhesive resins may be used alone or in combination of two or more.

In the shielding film of the present invention, the conductive adhesive layer has a copper plating layer patterned by a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95%. The shape of the copper plating layer is not particularly limited, and may be appropriately selected depending on the required shielding property, the impedance to be controlled, and the like. The specific pattern of the copper plating layer is preferably a mesh pattern, and examples of the shape of the opening include a triangle such as an equilateral triangle, an isosceles triangle, and a right triangle; a square shape such as a square, a rectangle, a diamond, a parallelogram, or a trapezoid; (Positive) pentagon, (positive) hexagonal, (positive) octagonal, (positive) dodecagonal (positive) n-angle (n is an integer of 5 or more); geometric figures such as circles, circles, and stars. The openings are preferably arranged at equal intervals, The reason is that the electromagnetic wave shielding property is excellent. 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 shielded printed circuit board. When the aperture ratio is less than 40%, the impedance control range becomes small without adjusting the line width of the signal circuit of the shielded printed circuit board. By setting the aperture ratio to 95% or less, the impedance of the signal line of the shield printed circuit board can be made to a desired value, and the capacitance can be reduced to prevent waveform passivation. Further, the aperture ratio in the present invention is an aperture ratio in the case where the portion having no copper plating layer is the opening portion in the copper plating layer. Further, the layer (A-2) formed by using the conductive ink 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 film thickness of the copper plating layer to 0.2 μm or more, the impedance of the signal line of the shield printed circuit board can be set to a desired value, and the capacitance can be reduced to prevent waveform passivation. When the film thickness of the copper plating layer exceeds 20 μm, it is difficult to satisfy the requirement that the shield printed wiring board itself is made thinner, and when it is used as a flexible printed circuit board, there is a problem that the flexibility is largely lowered. Further, the film thickness of the copper plating layer is preferably in the range of 0.5 to 8 μm.

The method for forming the copper plating layer is a method in which the pattern of the opening portion is removed by etching treatment from a copper foil. However, this method has a problem that the manufacturing method is complicated or the copper plating layer is difficult to be thinned. Therefore, in the present invention, it is easy to pattern the layer of the copper plating layer according to the required aperture ratio and to increase the degree of freedom in the design of the impedance control, and to use the layer formed using the conductive ink described below (A- 1) After the pattern is formed, the copper plating layer is formed thereon.

As described above, the conductive ink is used as a base of a copper plating layer for patterning, and is excellent in adhesion to a copper plating layer formed thereon or plating deposition property at the time of copper plating. It is preferred that the metal nanoparticles are contained as the conductive material (a2). Further, the metal nanoparticle is preferably a metal nanoparticle dispersed by a polymer dispersant in terms of excellent adhesion to the second insulating protective layer described below.

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 amine group, a cyano group, an ethyl ethoxycarbonyl group, a phosphorus atom-containing group, a thiol group, a thiocyanate group, and a glycine group.

The metal nanoparticles include a transition metal or a compound thereof, and among the transition metals, an ionic transition metal is preferred. Examples of the ionic transition metal include metals such as copper, silver, gold, nickel, palladium, platinum, and cobalt, or a composite of these metals. These metal nanoparticles may be used alone or in combination of two or more. Further, among the metal nanoparticles, in particular, silver nano particles are preferable in terms of operational problems such as oxidative degradation and cost.

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

The oxide of the above transition metal is usually in an inert (insulating) state. However, for example, it can be treated by using a reducing agent such as dimethylamine borane to expose the metal to impart activity (electric conductivity).

In addition, as the metal whose surface is coated with an organic material, a resin particle (organic material) formed by an emulsion polymerization method or the like may be contained in the metal. These are generally in an inert (insulating) state. For example, the organic substance may be removed by using a laser or the like to expose the metal to impart activity (electrical conductivity).

As the conductive material (a2), those having a particle diameter of about 1 to 100 nm are preferably used. When an average particle diameter of 1 to 50 nm is used, conductivity with a micron-sized average particle diameter is used. In comparison with the case of a substance, a fine conductive pattern can be formed, and the resistance value after baking as described below can be further reduced, and thus it is more preferable. Further, in the present invention, the average particle diameter is a volume average value measured by a dynamic light scattering method by diluting the above-mentioned conductive substance (a2) with a dispersion good solvent. This measurement can be made by Microtrac. "Nanotrac UPA".

In the shielding film of the present invention, a layer (A-2) formed using a conductive ink is provided inside the opening of the patterned copper plating layer. The layer (A-2) is embedded in the opening of the copper plating layer and functions to improve the shielding property of electromagnetic waves. The shape of the layer (A-2) is not particularly limited, and may be appropriately selected according to the required electromagnetic wave shielding effect. In order to improve the shielding performance of the electromagnetic wave, it is preferable that the opening area of the copper plating layer is 15 The above layer (A-2) is formed in a range of ~95%, more preferably in the range of 40 to 95%. The layer (A-2) may be in contact with the copper plating layer. However, when the copper plating layer is produced by the following electrolytic copper plating method, the layer (A-2) is preferably not in contact with the copper plating layer.

Examples of the specific pattern shape of the layer (A-2) include a triangle such as an equilateral triangle, an isosceles triangle, and a right triangle; a square shape such as a square, a rectangle, a rhombus, a parallelogram, and a trapezoid; (positive) pentagon, (positive) Hexagon, (positive) octagon, (positive) dodecagonal (positive) n-angle (n is an integer of 5 or more); geometric figures such as circles, circles, stars, etc.; swirl, ring, coil, Spiral and other shapes.

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 circuit board can be improved. By setting the film thickness of the layer (A-2) to less than 2 μm, a difference in film thickness can be formed with the copper plating layer, and if the film thickness of the layer (A-2) is thinner than the copper plating described above Since the film thickness of the layer is easy to adjust the impedance of the shield printed circuit board to a desired value, it is preferable.

The film thickness of the copper plating layer is preferably set to be 3 to 100 times the film thickness of the layer (A-2). That is, by making the thickness of the metal layer inside the opening thin, and making the copper plating layer of the opening pattern portion thick, the impedance can be made to a desired value, and the capacitance can be reduced to prevent the waveform from being passivated. It can also shield electromagnetic waves.

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

The above layer (A-2) may be formed only of a conductive ink or may be formed on a conductive ink. Formed as a metal plating layer. The metal plating layer is not particularly limited, and examples thereof include copper, nickel, gold, silver, platinum, palladium, chromium, and tin. The method of performing plating on the layer (A-2) can be carried out by electroless plating.

The electroless plating method is a method in which, for example, a conductive material constituting the pattern of the layer (A-2) is brought into contact with an electroless plating solution to precipitate a metal contained in the electroless plating solution. An electroless plating layer (film) containing a metal film.

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

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

Further, as the electroless plating solution, a dye containing a compounding agent such as acetic acid or formic acid; malonic acid, succinic acid, adipic acid, maleic acid, or the like may be used as needed. a dicarboxylic acid compound such as butenedioic acid; a hydroxycarboxylic acid compound such as malic acid, lactic acid, glycolic acid, gluconic acid or citric acid; glycine acid, alanine, iminodiacetic acid, arginine, aspartic acid An amino acid compound such as glutamic acid; an amine-based polycarboxylic acid compound such as iminodiacetic acid, nitrogen triacetic acid, ethylenediamine diacetic acid, ethylenediaminetetraacetic acid or diamethylenetriaminepentaacetic acid; An acid, or a soluble salt of such an organic acid (sodium salt, potassium salt, ammonium salt, etc.); an amine compound such as ethylenediamine, di-ethyltriamine or tri-ethyltetramine.

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

The layer (A-1) and the layer (A-2) formed by using the conductive ink are formed on the second insulating protective layer described below in the production method of the present invention, in order to further improve the following The surface of the second insulating protective layer is in close contact with the layer (A-1) and the layer (A-2), and the polymer forming the second insulating protective layer preferably has the following reactive functional group [Y] .

Further, even when the polymer forming the second insulating protective layer described below does not have the following reactive functional group [Y], the surface of the second insulating protective layer is coated with a polymer. After the polymer layer (B) is dried and the polymer layer (B) is formed thereon, the layer (A-1) and the layer (A-2) are formed thereon, and the surface of the second insulating protective layer described below and the layer may be further improved ( A-1) and the adhesion of the above layer (A-2). Further, the polymer forming the polymer layer (B) preferably has the following reactive functional group [Y].

In the case where the polymer layer (B) having the following reactive functional group [Y] is provided, it is preferred to use the conductive ink as the conductive ink to further improve the adhesion between the copper plating layer and the second insulating protective layer described below. It is a compound (a1) containing a reactive functional group [X] and the above-mentioned electrically conductive substance (a2).

The reactive functional group [X] of the above compound (a1) is bonded to the following reactive functional group [Y], and specific examples thereof include an amine group, a guanamine group, and a hydroxyalkylguanamine. Base, carboxyl group, acid anhydride group, carbonyl group, acetamethylene oxide, epoxy group, alicyclic epoxy group, oxetane ring, vinyl group, allyl group, (meth) acrylonitrile group, A compound such as an isocyanate group or an (alkoxy)decyl group, a sesquioxane compound or the like is used.

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

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

Further, by using a compound (a1) having a plurality of basic nitrogen-containing groups in one molecule, one of the basic nitrogen-containing groups is formed in the above layer (A-1) and the above layer (A-) 2) the pattern, the reactive functional group [Y] of the polymer forming the second insulating protective layer described below or the polymer forming the polymer layer (B) is involved in bonding, and the others contribute Interacting with the conductive material (a2) such as silver contained in the layer (A-1) and the layer (A-2), the adhesion between the copper plating layer and the second insulating protective layer finally obtained can be further improved. Sex, so it is better.

The compound (a1) having the above-mentioned basic nitrogen atom-containing group can further improve the dispersion stability of the above-mentioned conductive material (a2) and the adhesion to the second insulating protective layer described below. In the surface, it is preferably a polyalkyleneimine or a polyalkyleneimine having a polyoxyalkylene structure containing an oxyalkyl group.

As the polyalkyleneimine having the above structure, the polyethylenimine and the polyoxyalkylene group may be linearly bonded, or may be the same as the above-mentioned polyethylenimine. The main chain is grafted with the above polyoxyalkylene group on its side chain.

Specific examples of the polyalkyleneimine having a polyoxyalkylene group structure include a block copolymer of a polyethylenimine and a polyoxyethylene, and a main chain of the polyethylenimine. a part of an imine group present in an addition reaction with ethylene oxide to introduce a polyoxyethylene structure, and an amine group having a polyalkylene glycol and a hydroxyl group and a ring of polyoxyethylene glycol The epoxy group obtained by the oxygen resin is obtained by a reaction or the like.

As a commercial item of the above-mentioned polyalkyleneimine, "PAO2006W", "PAO306", "PAO318", "PAO718", etc. of "EPOMIN (registered trademark) PAO series manufactured by Nippon Shokubai Co., Ltd." .

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

The reactive functional group [X] possessed by the above compound (a1) is a carboxyl group, an amine group, a cyano group, an ethyl ethoxy group, a phosphorus atom-containing group, a thiol group, a thiocyanate group, or a glycine acid. In the case of a base or the like, since these functional groups also function as a functional group for coordination with the metal nanoparticles, the above compound (a1) can also be used as a polymer dispersant for metal nanoparticles.

In order to impart printing suitability to the above-described various types of printing methods, it is preferred to use a solvent to obtain a suitable viscosity. Examples of the solvent include an aqueous medium such as distilled water, ion-exchanged water, pure water, and ultrapure water; and an organic solvent such as an alcohol solvent, an ether solvent, a ketone solvent, or an ester solvent.

Examples of the above alcohol solvent or ether solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, heptanol, and hexanol. Octanol, decyl alcohol, decyl alcohol, undecyl alcohol, dodecanol, tridecyl alcohol, tetradecanol, pentadecyl alcohol, 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-butanediol, 1,4-butanediol, 2,3-butanediol, glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Alcohol 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 monobutyl ether, and the like.

Examples of the ketone solvent include acetone, cyclohexanone, and methyl ethyl ketone. Further, examples of the ester solvent include ethyl acetate, butyl acetate, 3-methoxybutyl acetate, and 3-methoxy-3-methylbutyl acetate. Further, examples of the other organic solvent include cyclohexane, toluene, octane, decane, decane, dodecane, tridecane, tetradecane, cyclooctane, xylene, mesitylene, and ethyl. Non-polar solvents such as benzene, dodecylbenzene, tetralin, and trimethylbenzene may be used in combination with other solvents as needed. Further, a solvent such as mineral spirits or solvent naphtha as a mixed solvent may be used in combination.

The conductive ink can be produced, for example, by mixing the polymer dispersant, the conductive material, and optionally the solvent. Specifically, it can be produced by adding an ion solution of the above-mentioned conductive substance prepared in advance to a medium in which a compound having a polyalkyleneimine chain, a hydrophilic segment and a hydrophobic segment is dispersed. The metal ion is reduced.

Further, in the conductive ink, in order to improve the dispersion stability of the conductive material in a solvent such as an aqueous medium or an organic solvent, and the wettability to the surface to be coated, a surfactant or an antifoaming agent may be added as needed. , rheology modifiers, etc.

In the present invention, the conductive ink is printed on the second insulating protective layer to form a pattern including the layer (A-1) and the layer (A-2), and as a method of printing the conductive ink, for example, List: inkjet printing, reverse printing, soft printing, screen Printing method, gravure printing method, gravure offset printing method, and the like. Among these printing methods, the ink jet printing method is preferred because when the pattern of the copper plating layer is changed in order to control the impedance of the shield printed circuit board, it is not necessary to produce a corresponding printing plate according to the pattern, thereby The pattern change can be easily dealt with.

As the above inkjet printing method, a person called an inkjet printer can be generally used. Specifically, "Konica Minolta EB100, XY100" (manufactured by Konica Minolta IJ Co., Ltd.), "Dimatix Materials Printer DMP-3000, DMP-2831" (manufactured by Fuji Film Co., Ltd.), and the like are exemplified.

Further, in the case of producing a high-definition metal layer pattern, it is preferable to use a reverse printing method in which the printing precision of fine lines is excellent.

As a reverse printing method, a letterpress reverse printing method and a gravure reverse printing method are known, and for example, a method in which the conductive ink is applied to the surface of each of the printing cloths to be in contact with a non-drawing portion is disclosed. And selectively transferring the conductive ink corresponding to the non-line portion to the surface of the plate, thereby forming the pattern on the surface of the printing cloth or the like, and then transferring the pattern to the second insulation protection On the layer (surface).

Further, in the case where the polymer layer (B) is provided in order to further improve the adhesion between the surface of the second insulating protective layer and the layer (A-1) and the layer (A-2) as described above, Examples of the polymer forming the polymer layer (B) include a urethane resin, a vinyl resin, a urethane-vinyl composite resin, an epoxy resin, a quinone imine resin, and a guanamine. Various resins and solvents such as resins, melamine resins, phenol resins, polyvinyl alcohol, and polyvinylpyrrolidone.

Among the resins used as the polymer (B), a urethane resin, a vinyl resin, a urethane-vinyl composite resin is preferred, and an amine group having a polyether structure is more preferably selected. a group consisting of a formate resin, a urethane resin having a polycarbonate structure, a urethane resin having a polyester structure, an acrylic resin, and a urethane-acrylic composite resin More than one type of resin. Further, a urethane-acrylic composite tree The grease is more preferable because it can obtain a conductive pattern having excellent adhesion and conductivity.

When the conductive ink contains the compound (a1) having the reactive functional group [X], the polymer forming the polymer layer (B) preferably has a reaction with the reactive functional group [X]. Compound (b1) of functional group [Y]. The compound (b1) having a reactive functional group [Y] may, for example, be an amine group, a guanamine group, a hydroxyalkylguanamine group, a carboxyl group, an acid anhydride group, a carbonyl group, an ethyl acetoxy group, or an epoxy group. a compound such as an alicyclic epoxy group, an oxetane ring, a vinyl group, an allyl group, a (meth) acrylonitrile group, a (blocked) isocyanate group, or an (alkoxy) decyl group, Semi-oxane compounds and the like.

Particularly, in the case where the compound (a1) having the reactive functional group [X] in the conductive ink is the compound (a1) having the above-mentioned basic nitrogen atom-containing group, the polymer layer (B) is formed. The reactive functional group [Y] in the polymer is preferably a carboxyl group, a carbonyl group, an ethyl oxime oxime group, an epoxy group, an alicyclic epoxy group, a hydroxyalkyl guanylamino group, an isocyanate group, a vinyl group, (a) The reason is that the acrylonitrile group and the allyl group are improved in adhesion between the metal layer finally obtained and the second insulating protective layer.

The method of applying the polymer of the polymer layer (B) to the surface of the second insulating protective layer described below may, for example, be a gravure printing method, a coating method, a screen printing method, a roll coating method, or the like. Rotary coating method, spray method, etc.

Further, in order to further improve the adhesion to the polymer layer (B), the surface of the second insulating protective layer described below may be subjected to a dry discharge treatment such as a corona discharge treatment method or a dry treatment such as an ultraviolet treatment method. The surface treatment is carried out by a wet treatment method using water, an acidic or alkaline chemical solution, an organic solvent or the like.

The method of applying the polymer of the polymer layer (B) to the surface of the second insulating protective layer and removing the solvent contained in the coating layer, and the usual method is, for example, drying using a dryer to make the above The solvent evaporates. The drying temperature is preferably set to a temperature within a range in which the solvent can be volatilized without adversely affecting the support.

Regarding the thickness of the polymer (B) layer formed by using the above polymer (B), it is possible to further The step of improving the adhesion between the second insulating protective layer and the metal layer is preferably in the range of 5 to 5,000 nm, more preferably in the range of 10 to 500 nm.

Further, the polymer (B) may be used as the second insulating protective layer as it is, or the polymer (B) may be used in combination with the second insulating protective layer. In this case, the polymer (B) It must be present in the portion of the second insulating protective layer that is in contact with the conductive ink.

Next, in order to form a pattern as a plating base by using the conductive ink, a baking step is performed after applying the conductive ink, and the baking step is performed by causing conductive substances contained in the conductive ink to be mutually The plating substrate pattern having conductivity is formed by bonding and bonding. The calcination is preferably carried out in a temperature range of 80 to 300 ° C for about 1 to 200 minutes. Here, in order to obtain a plating base pattern excellent in adhesion to the second insulating protective layer, it is more preferable to set the baking temperature to a range of 100 to 200 °C.

The calcination can be carried out in the atmosphere, but in order to prevent oxidation of the electroconductive substance, part or all of the calcination step can be carried out under a reducing atmosphere.

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

The pattern comprising the layer (A-1) and the layer (A-2) formed by using the conductive ink as described above is preferably a conductive layer having a range of 80 to 99.9% by mass in the pattern. A substance, a polymer dispersant containing 0.1 to 20% by mass.

The film thickness of the layer (A-1) and the layer (A-2) formed by using the conductive ink can be preferably 0.05 in terms of forming a conductive pattern having low electrical resistance and excellent electrical conductivity. ~1μm range.

Next, in the shielding film and the shield printed circuit board of the present invention, the main conductive layer on the side of the shielding film is formed by using the layer (A-1) formed of the conductive ink as a plating base pattern thereon. Pattern with a film thickness of 0.5 to 20 μm and an aperture ratio of 40 to 95% Copper plated layer. On the other hand, in the above-mentioned Patent Document 2, as a conductive layer, a method of forming a conductive portion by etching a metal foil by a method of printing a conductive ink or a conductive paste on a substrate film in a specific pattern is disclosed. In the method, a method of forming a metal layer of a specific pattern by vapor deposition or sputtering of a metal, and further, as the conductive layer, a metal wire mesh is disclosed. Moreover, in the above-mentioned Patent Document 2, as a material of the conductive layer, a metal such as gold, silver or copper or an alloy thereof, a resin containing a conductive filler, a conductive polymer or the like is preferably used. However, it is known that when a resin containing a conductive filler is used as a material of a conductive layer or as a conductive ink or a conductive paste, the conductive layer itself lacks conductivity, and the transmission loss of a signal line of a printed circuit board is intensified. Moreover, if the opening is formed by etching the metal foil, the manufacturing process is complicated, the price of the shielded printed circuit board is high, or it is difficult to arbitrarily adjust the thickness of the conductive layer (thin film). Further, in the case of a method of forming a metal layer of a specific pattern by vapor deposition or sputtering of a metal, only a conductive layer having a small thickness can be formed, and further, there is a problem in a method of forming an opening pattern. Further, in the case of using a metal wire mesh, it is difficult to achieve thinning of the conductive layer pattern, and it is restricted in terms of reducing the area of the opening. In the present invention, the layer (A-1) formed by patterning using the conductive ink is used as a plating substrate, and copper plating is performed thereon to obtain a copper plating layer, and the copper plating layer is used as a shielding film side. The conductive layer can solve all the above problems.

Examples of the method for forming the copper plating layer include a wet plating method such as an electrolytic plating method and an electroless plating method, and two or more of these plating methods may be combined to form the copper plating layer.

In the plating method, the adhesion between the pattern of the layer (A-1) and the copper plating layer formed by the plating method is further improved, and in terms of obtaining a pattern having excellent conductivity, The wet plating method such as electrolytic plating or electroless plating is more preferably an electrolytic plating method in terms of productivity or excellent mechanical properties of the obtained metal film. Further, when copper plating is performed on the layer (A-1) which is a pattern having an opening portion, It is preferably carried out by electrolytic plating.

The electrolytic plating method is a method of, for example, contacting a surface of the metal constituting the layer (A-1) or the surface of the electroless plating layer (film) formed by the electroless treatment with an electrolytic plating solution. In the state of being energized, 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) provided on the cathode to form an electrolytic plating layer (metal film).

Examples of the electrolytic plating solution include a sulfide containing copper, sulfuric acid, and an aqueous medium. Specific examples include those containing copper sulfate, sulfuric acid, and an aqueous medium.

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

Compared with the electroless plating method, the electrolytic plating treatment method is preferred because it does not use a highly toxic substance and is excellent in workability. Further, electrolytic copper plating is preferable to electroless copper plating because it can shorten the plating time and easily control the thickness of the plating film. Further, the copper plating layer obtained by electrolytic copper plating is excellent in mechanical properties, is not easily broken even when bent, and has excellent flexibility. Therefore, when it is used for a flexible printed circuit board, it is preferably used. A copper plating layer formed by electrolytic copper plating.

In the copper plating layer, a plating layer of another metal may be laminated on the copper plating layer. If a nickel plating layer, a gold plating layer, or a tin plating layer is provided, oxidative degradation or corrosion of the surface of the copper plating layer 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 as long as the conductive layer is excellent in electrical conductivity and can be used for the film formation of the shield printed wiring board. Further, in the case where the copper plating layer is formed by electrolytic plating, the thickness of the layer can be adjusted by controlling the processing time in the copper plating treatment step, the current density, the amount of the additive for plating, and the like.

In the shield printed wiring board of the present invention, a second insulating protective layer is provided on the copper plating layer, the layer (A-1), and the layer (A-2). As the second insulating protective layer, a sheet or film of an insulating resin or a coating layer of an insulating resin is contained. Sheet as insulating resin The material or film may, for example, be a polyester film, a polyolefin film, a polyimide film, a polyimide film, a polyphenylene sulfide film, a polyethylene naphthalate film, or a liquid crystal polymer (LCP). Membrane, polycycloolefin film, and the like. As the coating layer of the insulating resin, a polyolefin resin such as a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene or a polypropylene, a guanamine resin or an amidoxime may be used singly or in combination of two or more kinds. a thermoplastic resin such as an imide resin, a styrene-butadiene resin, an acrylonitrile-butadiene resin, a (meth)acrylic-butadiene resin, a (meth)acrylic resin, or a urethane resin, or A thermosetting resin such as a phenol resin, an epoxy resin, a melamine resin or an alkyd resin, or an ultraviolet curable resin such as a urethane-acrylate, an epoxy-acrylate or an acrylic acrylate. Among these, it is preferable to use a thermosetting resin or an ultraviolet curable resin, preferably an epoxy resin, in consideration of the severe thermal conditions (for example, during reflow) of an electronic device on which a printed circuit board is mounted. a urethane resin, a polyester resin, a melamine resin, an acrylic resin, a urethane-acrylate, an epoxy acrylate, an acryl methacrylate, or the like, alone or in combination of two or more kinds, Or used in combination with a crosslinking agent or the like. Further, in the case of being used as a flexible shield printed circuit board, it is preferred to contain a urethane resin.

The method for producing a barrier film of the present invention includes, for example, a method in which the polymer layer (B) is formed directly on the second insulating protective layer or on the second insulating protective layer, and then formed of a conductive ink. An opening pattern having an opening ratio of 40 to 95%, forming an opening internal pattern of 15 to 95% of an opening area inside the opening of the opening pattern, and performing electrolytic copper plating on the opening pattern to form a copper plating layer, and forming a copper plating layer thereon A conductive adhesive layer.

Moreover, a method of forming an opening pattern having an aperture ratio of 40 to 90% by using a conductive ink on the second insulating protective layer or the polymer layer (B) provided on the second insulating protective layer may be mentioned. a pattern of 15 to 95% of the opening area is formed inside the opening of the opening pattern, and electroless plating is performed on the opening pattern and the pattern formed inside the opening to form a copper plating layer, and then only the opening pattern is implemented Electroplating copper to form plating A copper layer on which a conductive adhesive layer is formed.

As a method of forming an opening pattern having an opening ratio of 40 to 95% and forming a pattern of 15 to 95% of an opening area inside the opening of the opening pattern, the method (1): forming an opening pattern by using a conductive ink, and opening the opening The pattern is subjected to electrolytic copper plating to form a copper plating layer, and then an open internal pattern of 15 to 95% of the opening area is formed by the conductive ink inside the opening pattern; and the method (2): using the conductive ink to simultaneously form the opening pattern and In the internal pattern of the opening, electrolytic copper plating is performed only on the opening pattern to form a copper plating layer; in particular, the method of forming the opening pattern and the internal pattern of the opening at the same time as (2) is excellent in productivity, and thus is preferable. In the case of the method of the above (2), since it is necessary to perform electrolytic copper plating only on the opening pattern, in order to use only the opening pattern as the conductive layer of electrolytic copper plating, it is preferable that the opening pattern is not in contact with the internal pattern of the opening. Moreover, the method of the above (2) may be carried out by forming an opening pattern and an internal pattern of the opening, and then thickening both the opening pattern and the internal pattern of the opening by electroless plating, and only the opening pattern portion Electrolytic copper plating is performed to form a copper plating layer. In this case, it is also preferred that the opening pattern is not in contact with the internal pattern of the opening. Further, the method for forming the polymer layer (B), the layer (A-1), and the layer (A-2) described above is as described above.

As described above, the second insulating protective layer may be a sheet or a film of an insulating resin or a coating layer of an insulating resin. When a second insulating protective layer is formed by applying an insulating resin, a release film may be used as a supporting base. material.

As the release film, a plastic film or a release paper can be used. Examples of the plastic film include a polyester film, a polyolefin film, and a polyimide film. The film may be further provided with a polyfluorene-based release layer, a fluorine-based release layer, and an olefin. It is a film of a release layer or the like. For example, the release paper is provided with a caulking layer on a paper substrate, and a polyfluorene-based release layer, a fluorine-based release layer, and an olefin-based release layer are provided thereon.

As the second insulating protective layer formed by coating, for example, a resin such as the above-exemplified resin may be applied, and an insulating resin may be applied to the release film to be dried. Drying, if necessary, the resin is cured by heat hardening or ultraviolet curing, and a second insulating protective layer can be produced.

In the method for producing a shielding film of the present invention, a conductive adhesive layer is formed on the copper plating layer. Specifically, as the conductive adhesive layer, the above-mentioned one can be used, and a conductive adhesive can be applied to the copper plating layer pattern and dried as necessary. The shielding film thus obtained can be used as a shielding film attached to the outermost surface of the shielded printed circuit board of the present invention.

A method of manufacturing the shield printed circuit board of the present invention will be described. For the printed circuit board constituting the shield printed circuit board of the present invention, a signal circuit and a ground circuit are formed on the printed circuit board substrate, and a first insulating protective layer is disposed thereon, and the first insulating protective layer is used to have the grounding A part of the circuit is exposed through the hole. Further, in the case where the shield printed circuit board of the present invention is formed into a flexible printed circuit board (FPC), a single-sided FPC having a printed circuit on only one side of the base film and a printed circuit on both sides of the base film can be suitably used. A two-face type FPC, a multi-layer FPC in which a plurality of layers of the FPC are laminated, a Flex Board (registered trademark) having a multi-layer component mounting portion and a cable portion, and a hard-soft combination of a member constituting the multi-layer portion (Flex- Rigid) substrate, or TAB tape for tape carrier package, etc.

Arranging on the first insulating protective layer of the printed circuit board in contact with the conductive adhesive layer of the shielding film of the present invention, by pressing the printed circuit board and the shielding film in a direction close to each other, The conductive adhesive layer of the shielding film is flowed to be connected to the ground layer of the printed circuit board, whereby the shield printed circuit board of the present invention can be manufactured. The printed circuit board and the shielding film are pressed to flow the conductive adhesive layer, and may be heated when bonding to the ground layer of the printed circuit board, and the conductive adhesive contains a resin capable of thermally hardening. At the time, the heating conditions can be adjusted according to the curing conditions of the resin. The temperature at the time of heating is usually preferably in the range of 50 to 250 °C.

Furthermore, the shield printed circuit board of the present invention may have a configuration in which a shielding film is attached to one surface of the printed circuit board, or a shielding film is attached to both surfaces.

[Examples]

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

[Preparation of Conductive Ink (1)]

In a mixed solvent of 35 parts by mass of ethylene glycol and 65 parts by mass of ion-exchanged water, a silver compound having an average particle diameter of 20 nm is dispersed by using a compound obtained by adding polyoxyethylene to polyethylenimine as a dispersing agent. Thus, a metal nanoparticle dispersion liquid containing metal nanoparticles and a polymer dispersant having a basic nitrogen atom-containing group as a reactive functional group was prepared. Then, the ion exchange water and the surfactant were added to the obtained metal nanoparticle dispersion to adjust the viscosity to 11 mPa. s, thereby preparing a conductive ink (1) for inkjet printing.

[Manufacture of resin for second insulating protective layer]

100 parts by mass of a polyester polyol (reaction of 1,4-cyclohexanedimethanol, neopentyl glycol, and adipic acid) in a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer Polyester polyol, hydroxyl equivalent weight: 1,000 g/eq), 17.2 parts by weight of 2,2-dimethylolpropionic acid, 21.7 parts by mass of 1,4-cyclohexanedimethanol, and 106.2 parts by mass of dicyclohexylmethane diisocyanate The mixture was mixed with 178 parts by mass of methyl ethyl ketone to cause a reaction, thereby obtaining an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal.

Then, by adding 13.3 parts by mass of triethylamine to the organic solvent solution of the urethane prepolymer obtained above, part or all of the carboxyl group of the above urethane resin is partially or completely neutralized. Further, 277 parts by mass of water was added and stirred sufficiently to obtain an aqueous dispersion of a urethane resin having a carboxyl group.

By adding 8 parts by mass of a 25% by mass aqueous solution of ethylenediamine to the aqueous dispersion of the urethane resin obtained above and stirring, the urethane resin chain is elongated, followed by aging and solvent removal. Thus, an aqueous dispersion of a urethane resin having a solid content of 30% by mass was obtained. Then, the quality of the aqueous dispersion 333 of the obtained urethane resin To the mixture, 30 parts by mass of sorbitol polyglycidyl ether (epoxy equivalent 170) was added and mixed to obtain a resin solution for a second insulating protective layer.

[Manufacture of Resin for Polymer Layer (B-1)]

180 parts by mass of ethyl acetate was added to a reaction vessel equipped with a mixer, a reflux cooling tube, a nitrogen gas introduction tube, a thermometer, a monomer mixture, a dropping funnel, and a dropping funnel for dropping a polymerization catalyst, and the temperature was raised to 80 while blowing nitrogen gas. °C. In a reaction vessel heated to 80 ° C, while maintaining the temperature in the reaction vessel at 80 ± 1 ° C while stirring, 60 parts by mass of methyl methacrylate and acrylic acid were dropped from different dropping funnels over 240 minutes. The mixture of 10 parts by mass of n-butyl ester and 30 parts by mass of glycidyl methacrylate was polymerized with a polymerization initiator solution containing 1 part by mass of azoisobutyronitrile and 20 parts by mass of ethyl acetate. After the 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. Then, ethyl acetate was added so that the nonvolatile content was 10% by mass, and an epoxy group was obtained as a reaction. A resin for the polymer layer (B-1) having a functional group.

[Manufacture of Resin for Polymer Layer (B-2)]

In a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, the polycarbonate polyol (the acid group equivalent obtained by reacting 1,4-cyclohexanedimethanol with a carbonate is 1000 g/eq. 100 parts by mass of polycarbonate diol), 9.7 parts by mass of 2,2-dimethylolpropionic acid, 5.5 parts by mass of 1,4-cyclohexanedimethanol, and 51.4 parts by mass of dicyclohexylmethane diisocyanate in methyl ethyl The reaction is carried out in 111 parts by mass of a ketone in a mixed solvent, whereby an organic solvent solution of a urethane prepolymer having an isocyanate group at a molecular terminal is obtained.

Then, by adding 7.3 parts by mass of triethylamine to the organic solvent solution of the urethane resin, one or all of the carboxyl groups of the urethane resin are partially or completely neutralized, and 355 parts by mass of water is further added. Stir well, thereby obtaining an aqueous dispersion of the urethane resin.

Then, by adding 4.3 parts by mass of a 25% by mass aqueous solution of ethylenediamine to the aqueous dispersion and stirring, the particulate polyurethane resin chain is elongated, followed by aging and solvent removal, thereby obtaining An aqueous dispersion of a urethane resin having a solid content concentration of 30% by mass.

140 parts by mass of deionized water was added to a reaction vessel equipped with a mixer, a reflux cooling tube, a nitrogen gas introduction tube, a thermometer, a monomer mixture, a dropping funnel, and a dropping funnel for dropping a polymerization catalyst, and the obtained amine group A was obtained. 100 parts by mass of the aqueous dispersion of the acid ester resin was heated to 80 ° C while blowing nitrogen gas. In a reaction vessel heated to 80 ° C, while maintaining the temperature in the reaction vessel at 80 ± 2 ° C while stirring, 60 parts by mass of methyl methacrylate and acrylic acid were dropped from different dropping funnels over a period of 120 minutes. The monomer mixture of 30 parts by mass of n-butyl ester and 10 parts by mass of N-n-butoxymethyl acrylamide was polymerized with 20 parts by mass of an aqueous solution of ammonium persulfate (concentration: 0.5% by mass).

After the completion of the dropwise addition, the mixture was stirred at the same temperature for 60 minutes, and then the temperature in the reaction vessel was cooled to 40 ° C. Then, deionized water was added so that the nonvolatile content became 20% by mass, and then 200 mesh filter cloth was used. Filtration was carried out to obtain a resin for a polymer layer (B-2) containing a carboxyl group and an N-n-butoxymethyl acrylamide group as a reactive functional group.

[Manufacture of Resin for Conductive Adhesive]

100 parts by mass of a polyester polyol (reaction of 1,4-cyclohexanedimethanol, neopentyl glycol, and adipic acid) in a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer a polyester polyol having a hydroxyl group equivalent of 1000 g/eq.), 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. The 178 parts by mass of methyl ethyl ketone was mixed and reacted, whereby a urethane resin having an isocyanate group at the molecular terminal was obtained. Then, 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 solvent solution of the urethane resin obtained above, 20 parts by mass of a bisphenol A type epoxy resin (epoxy equivalent weight 180) is added and mixed, and then a silver filler is added (Dayan Chemical Industry Co., Ltd.) 80 parts by mass of "S-201" manufactured by the company was mixed to prepare a conductive adhesive.

(Example 1)

A printed circuit board is used in which a copper circuit pattern having a thickness of 12 μm and a line width of 500 μm and a copper circuit pattern having a thickness of 12 μm and a line width of 150 μm are formed on a base film made of a polyimide substrate. In the circuit, the line spacing between the signal circuit and the ground circuit is set to 100 μm, the circuit length is set to 100 mm, and the film thickness of the adhesive layer of 15 μm and the film thickness of 12.5 μm is formed into a film thickness of 27.5. The first insulating protective layer of μm is provided with an opening of 400 μm square in the grounding circuit portion.

As the shielding film, the resin for the second insulating protective layer produced as described above was applied onto the polyester film which had been subjected to the release treatment so as to have a film thickness of 5 μm after drying, and dried to form a second insulating protective layer. Then, the resin for the polymer layer (B-1) produced as described above was applied so as to have a film thickness after drying of 0.2 μm, and dried to form a polymer layer (B-1).

Then, on the second insulating protective layer in which the polymer layer (B-1) was laminated by the above method, an ink jet printer ("100100" manufactured by Konica Minolta Co., Ltd.) was used for evaluation. With the print head KM512L, the discharge amount is 14 pL), the conductive ink (1) obtained above is printed in such a manner that the characteristic impedance of the shield printed circuit board is 80 Ω, that is, the print line width is 90 μm and the aperture ratio is 82%. In the lattice pattern, a non-opening portion having a square shape of 68% with respect to the opening portion area is printed in the opening without contacting the lattice pattern portion. A top view of the printed pattern is shown in FIG. Then, baking was performed at 120 ° C for 20 minutes to form a layer containing a conductive ink (1) having a square pattern having an opening ratio of 82% and having a square-shaped non-opening inside the opening (film thickness: 0.2 μm) .

Then, the lattice pattern portion of the layer containing the conductive ink (1) obtained above was set as a cathode, phosphorus-containing copper was set as an anode, and an electrolytic plating solution containing copper sulfate was used at a current density of 2 A/dm ² . Electrolytic copper plating was carried out for 10 minutes to form a copper plating layer having a thickness of 5 μm in a lattice pattern only portion of the surface of the layer containing the conductive ink. As the electrolytic copper plating solution, 70 g/L of copper sulfate, 200 g/L of sulfuric acid, 50 mg/L of chloride ion, and 5 ml/L of an additive ("Top Lucina SF-M" manufactured by Okuno Pharmaceutical Co., Ltd.) were used. The grid pattern portion after electrolytic copper plating had a line width of 100 μm and an aperture ratio of 80%, and the area of the layer containing the conductive ink (opening inner pattern) inside the opening was 71% of the opening area.

Then, the film thickness after drying is included on the entire surface of the conductive ink pattern including the copper plating layer of the lattice pattern of 80% of the opening ratio formed on the second insulating protective layer and the non-opening portion inside the opening. The conductive adhesive prepared above was applied to a thickness of 5 μm, and dried to prepare a shielding film.

Then, the printed circuit board provided with the opening portion of the ground circuit portion and the obtained shielding film are disposed so as to contact the conductive adhesive layer of the shielding film over the insulating protective layer of the printed circuit board. And pressing the printed circuit board and the shielding film in a direction in which they are close to each other (pressure: 1.96 MPa, heating temperature: 150 ° C, processing time: 30 minutes), and crimping the conductive adhesive layer of the shielding film And connected to the ground plane of the printed circuit board to make a shield printed circuit board.

(Examples 2 to 4)

Instead of the printed circuit board used in the embodiment 1, the pattern width of the copper circuit for signal shown in Table 1 was used. In addition, in place of the shielding film used in the first embodiment, the resin for the polymer layer (B) shown in Table 1 is used, and in order to make the characteristic impedance of the shield printed wiring board 80 Ω, the aperture ratio of the copper plating layer is A shield printed circuit board was produced in the same manner as in Example 1 except that the area ratio of the conductive ink layer (opening internal pattern) inside the opening of the opening area of the copper plating layer was as shown in Table 1. .

(Example 5)

Instead of the printed circuit board used in Example 1, the signal copper shown in Table 1 was used. The pattern width of the circuit. As the shielding film, the resin for the second insulating protective layer produced as described above was applied onto the polyester film which had been subjected to the release treatment so as to have a film thickness of 5 μm after drying, and dried to form a second insulating protective layer. Then, on the second insulating protective layer formed by the above method, using the same apparatus as in the first embodiment, the conductive ink (1) is printed in such a manner that the characteristic impedance of the shield printed circuit board is 80 Ω, that is, A grid pattern having a line width of 90 μm and an aperture ratio of 58% was printed, and a non-opening portion having a quadrangular shape with an area of 40% with respect to the area of the opening was printed so as not to be in contact with the lattice pattern portion. Then, baking was performed at 120 ° C for 20 minutes to form a layer containing a conductive ink (1) having a square pattern having an opening ratio of 58% and having a square-shaped non-opening inside the opening (film thickness: 0.2 μm) .

Then, the lattice pattern portion of the layer containing the conductive ink (1) obtained above was set as a cathode, and phosphorus-containing copper was set as an anode, and the surface of the layer containing the conductive ink was applied in the same manner as in Example 1. Only the lattice pattern portion was laminated with a copper plating layer having a thickness of 5 μm. The grid pattern portion after electrolytic copper plating had a line width of 100 μm and an aperture ratio of 56%, and the area of the layer containing the conductive ink (opening inner pattern) inside the opening was 43% of the opening area.

Then, the film thickness after drying is included on the entire surface of the conductive ink pattern including the copper plating layer of the lattice pattern having the opening ratio of 56% formed on the second insulating protective layer and the non-opening portion inside the opening. The conductive adhesive prepared above was applied to a thickness of 5 μm, and dried to prepare a shielding film.

Then, the printed circuit board provided with the opening portion in the ground circuit portion and the obtained shielding film are crimped onto the insulating protective layer of the printed circuit board in the same manner as in the first embodiment, so that the conductivity of the shielding film is made. The layer is then flowed and connected to the ground plane of the printed circuit board to form a shield printed circuit board.

(Example 6)

Instead of the printed circuit board used in the embodiment 1, the pattern width of the copper circuit for signal shown in Table 1 was used. Further, instead of the shielding film used in Example 1, Table 1 was used. A resin for the polymer layer (B) is shown. Then, on the second insulating protective layer in which the polymer layer (B-1) was laminated by the above method, the same apparatus as in Example 1 was used, and the characteristic impedance of the shield printed wiring board was 80 Ω as follows. The printed conductive ink (1), that is, a grid pattern having a line width of 90 μm and an aperture ratio of 74%, and a square shape in which the printing area is 69% with respect to the opening area without contacting the lattice pattern portion. Non-opening. Then, baking was performed at 120 ° C for 20 minutes to form a layer containing a conductive ink (1) having a lattice pattern having an opening ratio of 74% and having a square-shaped non-opening inside the opening (film thickness: 0.05 μm) .

Then, electroless copper plating was performed on the layer (thickness: 0.05 μm) containing the conductive ink (1) having a square pattern and having a non-opening portion having a square shape inside the opening, and the thickness was 0.2 μm. Electroless copper plating film. Further, electroless copper plating is carried out by using ARG (arginine, arginine) copper (manufactured by Okuno Pharmaceutical Co., Ltd.) under standard recommended conditions (ARG copper 1:30 ml/L, ARG copper 2: 15 ml/L, ARG copper 3: 200 ml/L) was bathed, the bath temperature was maintained at 45 ° C, and the plated material (conductive ink layer) was immersed therein for 15 minutes to precipitate a copper plating film.

Then, the lattice pattern portion in which the electroless copper plating film was formed on the layer containing the conductive ink (1) was set as a cathode, and the phosphorus-containing copper was set as an anode, and the same manner as in Example 1 was carried out. A copper plating film having a lattice pattern layer thickness of only 3 μm on the surface of the layer of the electroless copper plating film. The grid pattern portion after electrolytic copper plating has a line width of 97 μm and an aperture ratio of 72%. The area of the layer containing the electroless copper plating film (opening internal pattern) inside the opening is 70% of the opening area, and the film thickness is 0.2 μm. .

Then, the copper plating layer including the lattice pattern of 72% of the aperture ratio formed on the second insulating protective layer obtained above and the non-opening portion of the interior of the opening including the layer of the electroless copper plating film are The conductive adhesive prepared above was applied so as to have a film thickness of 5 μm after drying, and dried to prepare a barrier film.

Then, the printed circuit board provided with the opening portion in the ground circuit portion and the above obtained The obtained shielding film is pressure-bonded to the insulating protective layer of the printed circuit board in the same manner as in the first embodiment, and the conductive adhesive layer of the shielding film is flowed to be connected to the ground layer of the printed circuit board to form a shield printed circuit board. .

(Comparative Example 1)

Instead of the printed circuit board used in the first embodiment, a printed circuit board in which the line width of the signal copper circuit pattern is set to the line width described in Table 1 is used. Further, in place of the shielding film used in Example 1, the second insulating protective layer obtained was applied to the rolled copper foil having a thickness of 5 μm so as to have a film thickness after drying of 5 μm in order to have an aperture ratio of 0%. The second insulating protective layer is formed by drying with a resin. Then, the conductive adhesive obtained above was applied to the surface of the rolled copper foil opposite to the surface on which the second insulating protective layer was formed so as to have a film thickness after drying of 5 μm, and dried to have an aperture ratio of 0. Shielding film of % copper layer.

Then, a printed circuit board having a line width of a signal copper circuit pattern described in Table 1 and having an opening portion of 400 μm square in the ground circuit portion, and the above-obtained shielding film for insulation protection of the printed circuit board are provided. The layer is placed on the layer in contact with the conductive adhesive layer of the shielding film, and the printed circuit board and the shielding film are pressed in a direction close to each other (pressure: 1.96 MPa, heating temperature: 150 ° C, processing time: 30 minutes) The pressure-sensitive adhesive layer is connected to the ground layer of the printed circuit board to form a shield printed circuit board.

(Comparative Example 2)

An aperture ratio of 0% was produced in the same manner as in Comparative Example 1, except that the printed circuit board used in Comparative Example 1 was set to have the line width of the copper circuit pattern for the signal as shown in Table 1. Compare shielded printed circuit boards.

[Manufacture of Resin for Conductive Ink (R1) for Comparison]

Adding adipic acid, terephthalic acid and 3-methyl-1,5-pentanediol to a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dropping device and a nitrogen inlet tube 414 parts by mass of a diol having a number average molecular weight of 1006, 8 parts by mass of dimethylolbutanoic acid, 145 parts by mass of isophorone diisocyanate, and 40 parts by mass of toluene, and reacted at 90 ° C for 3 hours in a nitrogen atmosphere. . Then, 300 parts by mass of toluene was further added to the reaction solution to obtain a solution of a urethane prepolymer having an isocyanate group at the end.

Then, in the mixture obtained by mixing 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, the amine group obtained above is added. A solution of the formate prepolymer of 816 parts by mass was reacted at 70 ° C for 3 hours to obtain a solution of a polyurethane urethane resin. 144 parts by mass of toluene and 72 parts by mass of 2-propanol were added thereto to obtain a resin solution for a conductive ink (R1) for comparison of 30% by mass of the solid content of the polyurethane urethane resin.

[Preparation of Conductive Ink (R1) for Comparison]

333 parts by mass of the resin solution for the conductive ink for comparison and 20 parts by mass of the bisphenol A type epoxy resin ("JER828" manufactured by Mitsubishi Chemical Corporation) were stirred and mixed to obtain a resin composition solution. . 180 parts by mass of a conductive filler ("AgXF-301" manufactured by Fukuda Metal Foil Co., Ltd.) was added to 353 parts by mass of the resin composition solution, and the mixture was stirred and mixed to obtain a polyurea resin with respect to the polyurethane. A conductive ink (R1) for comparison of 100 parts by mass of the conductive filler in an amount of 100 parts by mass based on the total amount of the epoxy resin.

[Manufacture of resin for bonding layer]

20 parts by mass of a bisphenol A type epoxy resin was added to 333 parts by mass of a polyurethane urea resin solution prepared in the same manner as the above-mentioned conductive ink (R1) resin to obtain a resin for a bonding layer. .

(Comparative Example 3)

Regarding the production of the shielding film, the above-mentioned comparative conductivity is obtained by screen printing on a polyester film which has been subjected to release treatment to form a lattice pattern having a line width of 100 μm, an aperture ratio of 65%, and a film thickness of 5 μm after drying. The ink (R1) is dried to form a conductive layer. Then, The resin for the bonding layer obtained above was applied to the polyester film which had been subjected to the release treatment so that the film thickness after drying was 15 μm, and dried. Then, the conductive layer formed on the release film and the bonding layer formed on the release film were bonded to each other to form a shielding film.

Then, in place of the printed circuit board used in the first embodiment, a printed circuit board having a line width of a signal copper circuit pattern of 100 μm and an opening portion of 400 μm square in the ground circuit portion thereof, and the shield obtained as described above were used. The film is disposed in such a manner as to contact the conductive layer of the shielding film over the insulating protective layer of the printed circuit board, and pressurizes the printed circuit board and the shielding film in a direction close to each other (pressure: 1.96 MPa, heating temperature: 150 ° C) The treatment time: 30 minutes) was pressure-bonded, and the bonding layer of the shielding film was flowed to be connected to the ground layer of the printed circuit board, and a comparative shield printed circuit board having no conductive adhesive layer was produced.

[Measurement of electromagnetic wave shielding (transmission attenuation rate)]

With respect to the shield printed circuit board obtained in the above embodiments and comparative examples, according to ASTM D4935, the shielding effect measurement system of the coaxial tube type of KEYCOM is used to perform electromagnetic wave irradiation at 100 MHz to 6 GHz, and the electromagnetic wave is attenuated by the shielding film. The amount of attenuation was evaluated based on the following criteria. Furthermore, the measured value of the attenuation amount is expressed in decibels (in dB). Further, in general, it is good if the electromagnetic wave shielding property is 40 dB or more (99% or more of electromagnetic waves are cut off).

A: When the electromagnetic wave of 6 GHz in the microwave region is irradiated, it is displayed at 45 dB or more.

B: When an electromagnetic wave of 6 GHz is irradiated, it is displayed at 40 dB or more and less than 45 dB.

C: When an electromagnetic wave of 6 GHz is irradiated, it is displayed at 35 dB or more and less than 40 dB.

D: When the electromagnetic wave of 6 GHz is irradiated, the display is less than 35 dB.

[Measurement of characteristic impedance]

With respect to the shield printed circuit board obtained in the above examples and comparative examples, the characteristic impedance was measured using a network analyzer E5071C (manufactured by Agilent Technologies, Inc.).

[Evaluation of connection reliability of shielding film and grounding circuit of printed circuit board]

With respect to the shield printed circuit boards obtained in the above embodiments and comparative examples, it is assumed that the reflow soldering step is performed when the parts are connected: the reflow oven is passed at 240 ° C for 25 seconds, and then the shield printed circuit board is cooled to 25 °C, the reflow operation was repeated five times, and the volume resistance value between the shielding film before and after the shielding film and the ground circuit of the printed circuit board was measured, and the rate of change of the volume resistance value was calculated using the following formula, and the shielding film was evaluated based on the following criteria. Reliability of connection to ground circuits of printed circuit boards.

[evaluation benchmark]

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 rate of change of the volume resistance value is 50% or more and less than 80%.

D: The rate of change of the volume resistance value is 80% or more.

The above evaluation results are shown together in Table 1.

According to the results shown in the above Table 1, it was confirmed that the shield printed circuit boards of Examples 1 to 5 using the shielding film of the present invention were changed even when the pattern width of the signal copper circuit for the printed circuit board was changed between 50 and 150 μm. At the same time, the characteristic impedance of the shield printed circuit board can be controlled to 80 Ω by adjusting the aperture ratio of the metal layer (copper plating layer) of the shielding film. Further, the electromagnetic wave shielding property is also 45 dB or more, and the electromagnetic wave shielding property is also excellent.

Further, the shielding film of the present invention, that is, the film thickness of the shielding film portions of Examples 1 to 6, the total thickness of the second insulating layer, the copper plating layer, and the conductive adhesive layer is 13 to 16 μm and is thin, and the patent The film thickness of the shielding film is further reduced as compared with the shielding film which requires two layers of the opening metal layer and the non-opening metal layer (shielding layer) described in Document 3.

On the other hand, in the shield printed circuit board of Comparative Example 1, the pattern width of the signal copper circuit for the printed circuit board was set to 150 μm, and the aperture ratio of the metal layer (copper plating layer) of the shielding film was set to 0% (full plating) An example of a copper layer). The shielded printed circuit board has a characteristic impedance of 20 Ω and cannot be controlled to 80 Ω.

In the same manner as in Comparative Example 1, the shield printed circuit board of Comparative Example 2 was such that the opening ratio of the metal layer (copper plating layer) of the shielding film was 0% (total copper plating layer), and the signal for the printed circuit board was made of copper circuit. The pattern width was set to 20 μm, and even in this case, the characteristic impedance was 50 Ω. Further, since the shield printed circuit board has a pattern width of the copper circuit for signal of the printed circuit board to 20 μm, the transmission loss increases as the communication speed becomes faster as compared with the shield printed circuit board of the embodiment. problem.

According to the above results, it can be confirmed that the shield printed circuit board of the present invention can adjust the characteristic impedance by adjusting the aperture ratio of the metal layer of the shielding film even when the pattern width of the signal copper circuit of the printed circuit board is changed. Required and electromagnetic shielding is high.

Further, the shield printed circuit board of Comparative Example 3 is an example in which the conductive adhesive layer necessary for the shield printed circuit board of the present invention is not provided. The shielded printed circuit board has insufficient electromagnetic wave shielding properties, and further, there is a problem in connection reliability between the conductive layer on the shield film side and the ground circuit on the printed circuit side.

1‧‧‧Shielding film

2‧‧‧Second insulation protection layer

3‧‧‧Layer formed using conductive ink

4‧‧‧Copper plating with openings

5‧‧‧ Conductive adhesive layer

6‧‧‧First insulation protection layer

7‧‧‧Printed circuit board substrate

8‧‧‧Signal circuit

9‧‧‧ Grounding circuit

10‧‧‧First insulation protective layer removal part (grounding circuit and conduction part of copper plating layer having an opening)

11‧‧‧Printed circuit board

12‧‧‧Shielded printed circuit board

Claims (15)

A shielding film for shielding a printed circuit board provided with a signal circuit, a grounding circuit and a first insulating protective layer on a base insulating substrate, and having a laminated layer on the entire surface of the first insulating protective layer a conductive adhesive layer on the conductive adhesive layer, a copper plating layer patterned by a film thickness of 0.5 to 20 μm, an aperture ratio of 40 to 95%, and a conductive ink formed on the copper plating layer. a layer (A-1) and a layer (A-2) formed of a conductive ink on the opening of the copper plating layer on the conductive adhesive layer, and the conductive adhesive layer and the copper plating layer. a second insulating protective layer on the layer (A-1) and the layer (A-2). The shielding film of claim 1, further comprising a copper plating layer between the conductive adhesive layer and the layer (A-2). The shielding film of claim 1 or 2, 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 shielding film according to any one of claims 1 to 3, wherein the conductive ink is an ink containing, as a main component, metal nanoparticles as the conductive material (a2). The shielding film of claim 4, wherein the metal nanoparticle is dispersed by a polymer dispersant. The shielding film according to any one of claims 1 to 5, wherein the second insulating protective layer has a polymer between the layer (A-1) and the layer (A-2) formed by using the conductive ink. Layer (B). The shielding film of claim 6, wherein the conductive ink contains the compound (a1) and the conductive substance (a2), the compound (a1) having a reactive functional group [X], and The polymer layer (B) includes a layer containing a polymer of the compound (b1), and the compound (b1) has a reactive functional group [Y], and the compound (a1) contained in the conductive ink is used. The reactive functional group [X] having a reactivity with the reactive functional group [Y] of the above compound (b1) contained in the polymer layer (B) forms a bond. The shielding film according to claim 7, wherein the conductive ink contains the compound (a1) and the conductive substance (a2), and the compound (a1) has a group containing a basic nitrogen atom as a reactive functional group [X]. The shielding film of claim 8, wherein the compound (a1) having a basic nitrogen atom-containing group is a polyalkyleneimine or a polyalkylene having a polyoxyalkylene group having an oxy-ethyl group Imine. The shielding film according to any one of claims 7 to 9, wherein the above reactive functional group [Y] is selected from the group consisting of a ketone group, an epoxy group, a carboxyl group, an N-hydroxyalkyl group, an isocyanate group, a vinyl group, (methyl group) One or more of the group consisting of an acryloyl group and an allyl group. A shield printed circuit board characterized by having the shielding film according to any one of claims 1 to 10. A method for manufacturing a shielding film, characterized in that an opening pattern having an opening ratio of 40 to 90% is formed on a second insulating protective layer or a polymer layer (B) provided on a second insulating protective layer by using a conductive ink. And forming a pattern of 15 to 95% of the opening area inside the opening of the opening pattern, performing electrolytic copper plating on the opening pattern to form a copper plating layer, and forming a conductive adhesive layer thereon. A method for manufacturing a shielding film, characterized in that an opening pattern having an opening ratio of 40 to 90% is formed on a second insulating protective layer or a polymer layer (B) provided on a second insulating protective layer by using a conductive ink. And forming a pattern of 15 to 95% of the opening area inside the opening of the opening pattern, Electroless plating is performed on the opening pattern and the pattern formed inside the opening to form a copper plating layer, and then copper plating is performed on the opening pattern to form a copper plating layer, and a conductive adhesive is formed thereon. Floor. The method for producing a shielding film according to claim 12 or 13, wherein an ink having metal nanoparticles as a main component is used as the conductive ink (A), and an opening pattern having an aperture ratio of 40 to 90% is formed by inkjet printing. A pattern of 15 to 95% of the opening area is formed inside the opening of the opening pattern. A manufacturing method of a shielded printed circuit board, characterized in that: a signal circuit, a grounding circuit and an insulating protective layer are provided, and the insulating protective layer has a through hole in which a part of the grounding circuit is exposed, in the printed circuit board The shielding film of any one of claims 1 to 10 is disposed on the insulating protective layer of the board with the conductive adhesive layer contacting the insulating protective layer of the printed circuit board, and the printed circuit board and the shielding film are mutually Pressurization is performed in the approach direction, whereby the conductive adhesive layer of the shielding film flows to be connected to the ground layer of the printed circuit board.