JP6426865B1 - Electromagnetic shielding film - Google Patents

Abstract

To provide an electromagnetic wave shielding film in which peeling of a transfer film is easy. An electromagnetic shielding film includes an insulating protection layer, a transfer film provided on the surface of the insulating protection layer, and a conductive adhesive layer provided on the side of the insulating protection layer opposite to the transfer film. And 111 are provided. The surface on the insulating protective layer 112 side of the transfer film 115 has a maximum valley depth (Sv) of 1 μm or more and 6 μm or less and a maximum height (Sz) of 2 μm or more and 10 μm or less. [Selected figure] Figure 1

Description

  The present disclosure relates to an electromagnetic wave shielding film.

  An electromagnetic wave shielding film is used to protect electronic circuits from electromagnetic waves. The electromagnetic wave shielding film has a conductive adhesive layer and an insulating protective layer. The electromagnetic wave shielding film is generally manufactured by sequentially forming an insulating protective layer and a conductive adhesive layer on the surface of a base film. The base film is removed before the reflow process after the electromagnetic shielding film is bonded to the printed wiring board. In this case, the base film functions as a transfer film whose surface state is transferred to the insulating protective layer. Moreover, it functions as a protective film which protects an insulation protective layer until an electromagnetic wave shielding film adheres to a printed wiring board.

  In order to make the surface of the insulating protective layer a matte surface, it is general to provide asperities on the surface of the transfer film. By providing the unevenness, the adhesion between the transfer film and the insulating protective layer is enhanced, and the force required to peel the transfer film is increased. Moreover, when adhering an electromagnetic wave shielding film to a printed wiring board, it is common to apply a pressure of several MPa at a temperature of about 150 ° C. to 200 ° C. When exposed to such temperature and pressure, peeling of the transfer film becomes more difficult, and the transfer film may break.

  In order to prevent breakage at the time of peeling, making the transfer film itself hard to be broken is studied (see, for example, Patent Documents 1 and 2).

JP, 2015-185659, A JP, 2016-97522, A

  However, even if the transfer film itself is difficult to be broken, if a large force is required at the time of peeling, the productivity is lowered. In addition, the side of the insulating protective layer may be damaged. In order to make it easy to peel off the transfer film, it is desirable to control the interaction between the transfer film and the insulating protective layer.

  An object of the present disclosure is to enable realization of an electromagnetic wave shielding film in which peeling of the transfer film is easy.

  One aspect of the electromagnetic wave shielding film of the present disclosure includes an insulating protective layer, a transfer film provided on the surface of the insulating protective layer, and a conductive adhesive layer provided on the opposite side of the transfer protective film to the insulating protective layer. The surface on the insulating protective layer side of the transfer film has a maximum valley depth (Sv) of 1 μm to 6 μm, and a maximum height (Sz) of 2 μm to 10 μm.

  In one aspect of the electromagnetic wave shielding film, the variation coefficient of the maximum valley depth (Sv) and the variation coefficient of the maximum height (Sz) in the surface on the insulating protective layer side of the transfer film can be 0.2 or less.

  According to the electromagnetic wave shielding film of the present disclosure, peeling of the transfer film is facilitated, and productivity can be improved.

It is sectional drawing which shows the electromagnetic wave shield film which concerns on one Embodiment. It is sectional drawing which shows the modification of an electromagnetic wave shielding film. It is sectional drawing which shows the shield printed wiring board using the electromagnetic wave shielding film which concerns on one Embodiment.

  As shown in FIG. 1, the electromagnetic wave shielding film of this embodiment is provided on the side of the insulating protective layer 112, the transfer film 115 provided on the surface of the insulating protective layer 112, and the transfer film 115 of the insulating protective layer 112. And the conductive adhesive layer 111. Note that, as shown in FIG. 2, the shield layer 113 can also be provided between the insulating protection layer 112 and the conductive adhesive layer 111.

  The inventors set the maximum valley depth (Sv) in the surface on the insulating protective layer 112 side of the transfer film 115 to 6 μm or less, preferably 5 μm or less, and the maximum height (Sz) to 10 μm or less, preferably 9 μm or less It turned out that it becomes the transfer film 115 which can peel easily by carrying out.

  On the other hand, it has been found that there is a film which is difficult to peel even if the arithmetic mean height (Sa) is small. This is considered to be due to the fact that if there are deep valleys or high peaks at the pinpoint, even if it is an unevenness having the same level as the average value, the adhesion becomes high in that part and peeling becomes difficult. Therefore, it is important to control Sv and Sz of the transfer film 115. In addition, Sa, Sv, and Sz of the transfer film 115 can be measured by the method demonstrated in the Example.

  From the viewpoint of facilitating peeling, it is preferable that the maximum valley depth on the surface on the insulating protective layer 112 side of the transfer film 115 be small. However, in terms of making the surface of the insulating protective layer 112 a matte surface and a printed wiring board From the viewpoint of preventing the transfer film 115 from peeling off before fixation, Sv is 1 μm or more, preferably 2 μm or more, and Sz is 2 μm or more, preferably 3 μm or more.

  The peel strength of the transfer film 115 is preferably 5.0 N / 50 mm or less, more preferably 1.5 N / 50 mm or less from the viewpoint of easy peeling, and from the viewpoint of preventing the transfer film 115 from peeling before use. Preferably, it is 0.2 N / 50 mm or more, more preferably 0.5 N / 50 mm or more. The peel strength of the transfer film 115 can be measured by the method shown in the examples.

  From the viewpoint of facilitating peeling, the coefficient of variation of Sv and the coefficient of variation (SV) of Sz in the surface on the insulating protective layer 112 side of the transfer film 115 are preferably 0.2 or less, more preferably 0.15 or less. Do. The coefficient of variation as referred to herein is a value determined from the arithmetic mean and standard deviation of 10 points as shown in the examples.

  In addition, from the viewpoint of further facilitating the peeling, it is preferable to control parameters representing surface characteristics other than Sv and Sz. For example, the sharpness (Sku) is preferably 2.0 or more, more preferably 3.0 or more, preferably 8.5 or less, more preferably 7.5 or less. The minimum autocorrelation length (Sal) is preferably 7.5 μm or more, more preferably 8.5 μm or more, preferably 20.0 μm or less, more preferably 15.0 or less. The aspect ratio (Str) of the surface property is preferably 0.55 or more, more preferably 0.60 or more, and preferably 0.75 or less. The protruding valley height (Svk) is preferably 0.20 or more, more preferably 0.25 or more, preferably 0.75 or less, more preferably 0.70 or less. The load area ratio (Smr2) for separating the protruding valley portion and the core portion is preferably 90.0% or more, more preferably 94.0% or more. Parameters representing these surface properties can also be measured by the methods shown in the examples.

  The material of the transfer film 115 is not particularly limited, and polyester, polyolefin, polyimide, polyethylene naphthalate, porphyrinene sulfide or the like can be used. The thickness of the transfer film 115 is not particularly limited, but is preferably 25 μm or more, and preferably 100 μm or less from the viewpoint of facilitating peeling.

  At least one surface of the transfer film 115 may be sandblasted or the like in order to set Sv and Sz to predetermined values. Moreover, Sv and Sz can also be made into a predetermined value by containing microparticles | fine-particles. The fine particles to be added to the transfer film 115 are not particularly limited. For example, amorphous silica (colloidal silica), silica, talc, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, phosphate Inorganic particles such as magnesium, alumina, carbon black, titanium dioxide, kaolin, and synthetic zeolite, and organic particles such as crosslinked polystyrene particles and crosslinked acrylic particles can be used.

  A release agent layer (not shown) can be provided between the transfer film 115 and the insulating protection layer 112. The release agent layer can be formed by applying a silicon-based or non-silicon-based release agent to the surface of the transfer film 115 on the side of the insulating protective layer 112. When forming a release agent layer, the thickness can be about several micrometers-several dozen micrometers.

  In the present embodiment, the insulating protective layer 112 is not particularly limited as long as it has sufficient insulating properties and can protect the conductive adhesive layer 111 and, if necessary, the shield layer 113, for example, thermoplastic resin, thermosetting Can be formed using an organic resin, an active energy ray curable resin, or the like.

  The thermoplastic resin is not particularly limited, but a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, an imide resin, an acrylic resin or the like can be used. The thermosetting resin is not particularly limited, but phenol resins, epoxy resins, urethane resins, melamine resins, polyamide resins, alkyd resins and the like can be used. The active energy ray-curable resin is not particularly limited, but, for example, a polymerizable compound having at least two (meth) acryloyloxy groups in the molecule can be used. The protective layer may be formed of a single material or may be formed of two or more materials.

  The insulating protective layer 112 is not limited to the coloring agent, but if necessary, a curing accelerator, a tackifier, an antioxidant, a plasticizer, an ultraviolet absorber, an antifoamer, a leveling agent, a filler, a flame retardant, viscosity One or more of modifiers, antiblocking agents, etc. may be included.

  The insulating and protective layer 112 may be a laminate of two or more layers having different materials or physical properties such as hardness or elastic modulus. For example, if a laminate of an outer layer with low hardness and an inner layer with high hardness is used, the pressure applied to the shield layer 113 in the process of heating and pressing the electromagnetic wave shield film 101 against the printed wiring board 102 It can be relaxed. For this reason, it can suppress that the shield layer 113 is destroyed by the level | step difference provided in the printed wiring board 102. FIG.

  The insulating and protective layer 112 can be formed by applying the composition for insulating and protective layer on the surface of the transfer film 115. The composition for the insulating protective layer may be prepared, for example, by adding an appropriate amount of solvent to the resin for the insulating protective layer.

  The thickness of the insulating protective layer 112 is not particularly limited and can be set as appropriate, but is preferably 1 μm or more, more preferably 4 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, and further Preferably, it can be 5 μm or less. By setting the thickness of the insulating protective layer 112 to 1 μm or more, the conductive adhesive layer 111 and the shield layer 113 can be sufficiently protected. By setting the thickness of the insulating protective layer 112 to 20 μm or less, it is easy to set the elastic modulus and the breaking elongation of the electromagnetic wave shielding film 101 to predetermined values.

  When the shield layer 113 is provided, the shield layer 113 can be formed of a metal foil, a vapor deposition film, a conductive filler, or the like.

  The metal foil is not particularly limited, and can be a foil made of an alloy containing any of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc and the like, or two or more.

  The thickness of the metal foil is not particularly limited, but is preferably 0.5 μm or more, and more preferably 1.0 μm or more. When the thickness of the metal foil is 0.5 μm or more, when the high frequency signal of 10 MHz to 100 GHz is transmitted to the shield printed wiring board, the attenuation amount of the high frequency signal can be suppressed. Moreover, 12 micrometers or less are preferable, as for the thickness of metal foil, 10 micrometers or less are more preferable, and 7 micrometers or less are more preferable. While being able to hold down raw material cost as the thickness of a metal layer is 12 micrometers or less, judgment extension of a shield film becomes good.

  The deposited film is not particularly limited, and can be formed by depositing nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc and the like. For deposition, electrolytic plating, electroless plating, sputtering, electron beam evaporation, vacuum evaporation, chemical vapor deposition (CVD), metal organic deposition (MOCVD), or the like can be used.

  Although the thickness of a vapor deposition film is not specifically limited, 0.05 micrometer or more is preferable, and 0.1 micrometer or more is more preferable. When the thickness of the metal deposition film is 0.05 μm or more, the electromagnetic wave shielding film in the shield printed wiring board is excellent in the characteristic of shielding the electromagnetic wave. In addition, the thickness of the deposited metal film is preferably less than 0.5 μm, and more preferably less than 0.3 μm. When the thickness of the metal deposition film is less than 0.5 μm, the bending resistance of the electromagnetic wave shielding film is excellent, and it is possible to suppress the destruction of the shielding layer due to the level difference provided on the printed wiring board.

  In the case of the conductive filler, the shield layer 113 can be formed by applying a solvent containing the conductive filler on the surface of the insulating protective layer 112 and drying. As the conductive filler, metal fillers, metal-coated resin fillers, carbon fillers and mixtures thereof can be used. As the metal filler, copper powder, silver powder, nickel powder, silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, gold-coated nickel powder, etc. can be used. These metal powders can be prepared by an electrolysis method, an atomization method, or a reduction method. The shape of the metal powder may, for example, be spherical, flake, fibrous, dendritic or the like.

  In the present embodiment, the thickness of the shield layer 113 may be appropriately selected according to the required electromagnetic shielding effect and repeated bending / sliding resistance, but in the case of a metal foil, it is 12 μm from the viewpoint of securing breaking elongation. It is preferable to set it as the following.

  In the present embodiment, the conductive adhesive layer 111 contains a resin component such as a thermoplastic resin and a thermosetting resin, and a conductive filler.

  When the conductive adhesive layer 111 contains a thermoplastic resin, for example, a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, an imide resin, and an acrylic resin as a thermoplastic resin It can be used. These resins may be used alone or in combination of two or more.

  When the conductive adhesive layer 111 contains a thermosetting resin, for example, a phenolic resin, an epoxy resin, a urethane resin, a melamine resin, a polyamide resin, an alkyd resin, etc. can be used as the thermosetting resin. . The active energy ray-curable composition is not particularly limited. For example, a polymerizable compound having at least two (meth) acryloyloxy groups in the molecule can be used. These compositions may be used alone or in combination of two or more.

  The thermosetting resin includes, for example, a first resin component having a reactive first functional group, and a second resin component that reacts with the first functional group. The first functional group can be, for example, an epoxy group, an amido group, or a hydroxyl group. The second functional group may be selected according to the first functional group. For example, when the first functional group is an epoxy group, it may be a hydroxyl group, a carboxyl group, an epoxy group, an amino group or the like. Specifically, for example, when the first resin component is an epoxy resin, an epoxy group modified polyester resin, an epoxy group modified polyamide resin, an epoxy group modified acrylic resin, an epoxy group modified polyurethane polyurea resin, and a carboxyl group as the second resin component. A group modified polyester resin, a carboxyl group modified polyamide resin, a carboxyl group modified acrylic resin, a carboxyl group modified polyurethane polyurea resin, and a urethane modified polyester resin can be used. Among these, carboxyl group modified polyester resin, carboxyl group modified polyamide resin, carboxyl group modified polyurethane polyurea resin, and urethane modified polyester resin are preferable. When the first resin component is a hydroxyl group, an epoxy group modified polyester resin, an epoxy group modified polyamide resin, an epoxy group modified acrylic resin, an epoxy group modified polyurethane polyurea resin, a carboxyl group modified polyester resin as the second resin component, A carboxyl group modified polyamide resin, a carboxyl group modified acrylic resin, a carboxyl group modified polyurethane polyurea resin, a urethane modified polyester resin, etc. can be used. Among these, carboxyl group modified polyester resin, carboxyl group modified polyamide resin, carboxyl group modified polyurethane polyurea resin, and urethane modified polyester resin are preferable.

  The thermosetting resin may contain a curing agent that accelerates the thermosetting reaction. When the thermosetting resin has the first functional group and the second functional group, the curing agent can be appropriately selected according to the types of the first functional group and the second functional group. When the first functional group is an epoxy group and the second functional group is a hydroxyl group, an imidazole-based curing agent, a phenol-based curing agent, a cationic curing agent, or the like can be used. One of these may be used alone, or two or more may be used in combination. In addition, as an optional component, an antifoamer, an antioxidant, a viscosity modifier, a diluent, an antisettling agent, a leveling agent, a coupling agent, a coloring agent, a flame retardant and the like may be contained.

  The conductive filler is not particularly limited, and, for example, metal fillers, metal-coated resin fillers, carbon fillers and mixtures thereof can be used. Examples of the metal filler include copper powder, silver powder, nickel powder, silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, and gold-coated nickel powder. These metal powders can be produced by an electrolysis method, an atomization method, a reduction method or the like. Among them, silver powder, silver-coated copper powder and copper powder are preferable.

  The conductive filler preferably has an average particle diameter of 1 μm or more, more preferably 3 μm or more, preferably 50 μm or less, more preferably 40 μm or less, from the viewpoint of contact between the fillers. The shape of the conductive filler is not particularly limited, and may be spherical, flake-like, dendritic or fibrous.

  The content of the conductive filler can be appropriately selected according to the application, but it is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 95% by mass or less, in the total solid content. It is 90 mass% or less. From the viewpoint of embeddability, it is preferably 70% by mass or less, more preferably 60% by mass or less. Moreover, when realizing anisotropic conductivity, it is preferably 40% by mass or less, more preferably 35% by mass or less.

  The conductive adhesive layer 111 can be formed, for example, by applying a composition for a conductive adhesive layer on the insulating protective layer 112 or the shield layer 113 formed on the insulating protective layer 112. The composition for the conductive adhesive layer may be prepared by adding an appropriate amount of solvent to the resin and the filler for the conductive adhesive layer.

  The thickness of the conductive adhesive layer 111 is preferably 1 μm to 50 μm from the viewpoint of controlling the embeddability.

  In addition, you may bond the film for protection which can be peeled on the surface of the conductive adhesive layer 111 as needed.

  The electromagnetic wave shielding film 101 of the present embodiment can be combined with the printed wiring board 102 as shown in FIG. The electromagnetic wave shielding film 101 may have the shielding layer 113.

  The printed wiring board 102 has, for example, a printed circuit including a base member 122 and a ground circuit 125 provided on the base member 122. An insulating film 121 is adhered on the base member 122 by an adhesive layer 123. The insulating film 121 is provided with an opening for exposing the ground circuit 125. The exposed portion of the ground circuit 125 may be provided with a surface layer such as a gold plating layer. The printed wiring board 102 may be a flexible board or a rigid board.

  When the electromagnetic wave shielding film 101 is adhered to the printed wiring board 102, the electromagnetic shielding film 101 is disposed on the printed wiring board 102 so that the conductive adhesive layer 111 is positioned above the opening. Then, the electromagnetic wave shield film 101 and the printed wiring board 102 are vertically sandwiched by two heating plates (not shown) heated to a predetermined temperature (for example, 120 ° C.) and a predetermined pressure (for example, 0.5 MPa) ) For a short time (for example 5 seconds). The electromagnetic wave shielding film 101 is temporarily fixed to the printed wiring board 102 by this.

  Subsequently, the temperature of the two heating plates is set to a predetermined temperature (eg, 170 ° C.) higher than that at the time of the temporary fixing, and is pressurized at a predetermined pressure (eg, 3 MPa) for a predetermined time (eg, 30 minutes). By this, the electromagnetic wave shielding film 101 can be fixed to the printed wiring board 102. When the pressure is applied, the conductive adhesive layer 111 is sufficiently embedded in the opening, so that the strength and conductivity required for the electromagnetic shielding film 101 can be realized.

  After fixing the electromagnetic wave shielding film 101 to the printed wiring board 102, the transfer film 115 is peeled off. After this, solder reflow for component mounting is performed. The electromagnetic wave shielding film 101 of the present embodiment can easily peel off the transfer film 115 after fixing the electromagnetic wave shielding film 101 to the printed wiring board 102, and therefore, the production efficiency can be improved and competed.

  Hereinafter, the electromagnetic wave shielding film of the present disclosure will be described in more detail using examples. The following examples are illustrative and are not intended to limit the present invention.

<Preparation of electromagnetic wave shield film>
A release agent was applied to the surface of a predetermined transfer film. The composition for an insulating protective layer was applied to the surface of the transfer film coated with a release agent using a wire bar, and dried by heating to form an insulating protective layer. Next, after apply | coating the composition for electroconductive adhesive layers with a wire bar on an insulation protective layer, 100 degreeC * 3 minutes drying was performed and the electromagnetic shielding film was produced.

  The composition for the insulating protective layer had a two-layer structure of a hard coat layer of a polyester-based transparent resin having a thickness of 2 μm and a soft coat layer of a carbon black-containing epoxy-based black resin having a thickness of 3 μm. The composition for a conductive adhesive layer was prepared by adding a dendritic silver-coated copper powder having an average particle diameter of 5 μm as a conductive fine particle to a phosphorus-based flame retardant-containing epoxy resin. The thickness of the conductive adhesive layer was 15 μm.

<Measurement of surface properties>
The parameters relating to the surface properties were measured according to ISO 25178 using a laser microscope (VK-X210, manufactured by KEYENCE CO., LTD., Lens magnification 50 times). The measurement was performed on the surface of the unused transfer film cut out to 5.0 cm × 5.0 cm to form the insulating protective layer. The measurement was performed on any ten places in the plane, and the arithmetic mean value was adopted as the measurement value. In addition, standard deviation (SD) and coefficient of variation (CV) were calculated.

<Measurement of peel strength>
The electromagnetic wave shield film was pressed using a press under the conditions of temperature: 170 ° C., time: 30 minutes, pressure: 2 to 3 MPa. After the electromagnetic wave shielding film returned to normal temperature, the peeling strength of the transfer film was measured using a peeling strength tester (manufactured by Palmec Co., Ltd., PFT50S) for the peeling film on the surface. The measurement was conducted at normal temperature, under conditions of a tensile speed of 1000 mm / min and a peeling angle of 170 °. The measurement was performed ten times, and the minimum value, the maximum value and the average value were determined.

Example 1
A 50 μm thick PET film was used as a transfer film. The surface of the insulating protective layer after peeling off the transfer film was a matte surface. Sv in the insulation protective layer formation surface of a transfer film was 3.1 micrometers, Sz was 8.0 micrometers, and Sa was 0.69 micrometers. The variation coefficient of Sv was 0.15, and the change coefficient of Sz was 0.02. The minimum value of peel strength was 0.51 N / 50 mm, the maximum value was 0.75 N / 50 mm, and the average value was 0.63 N / 50 mm.

(Example 2)
A 50 μm thick PET film was used as a transfer film. The surface of the insulating protective layer after peeling off the transfer film was a matte surface. In the insulation protective layer formation surface of a transfer film, Sv was 2.5 micrometers, Sz was 6.6 micrometers, and Sa was 0.41 micrometer. The variation coefficient of Sv was 0.12, and the change coefficient of Sz was 0.08. The minimum value of the peel strength was 0.60 N / 50 mm, the maximum value was 0.76 N / 50 mm, and the average value was 0.68 N / 50 mm.

( Reference example )
A 50 μm thick PET film was used as a transfer film. The surface of the insulating protective layer after peeling off the transfer film was a matte surface. Sv was 5.9 μm, Sz was 9.6 μm, and Sa was 0.69 μm on the surface on which the insulating protective layer is formed of the transfer film. The variation coefficient of Sv was 0.07, and the change coefficient of Sz was 0.09. The minimum value of peeling strength was 0.98 N / 50 mm, the maximum value was 1.50 N / 50 mm, and the average value was 1.25 N / 50 mm.

(Comparative example 1)
A 50 μm thick PET film was used as a transfer film. The surface of the insulating protective layer after peeling off the transfer film was a matte surface. In the insulation protection layer formation surface of a transfer film, Sv was 6.8 micrometers, Sz was 11.4 micrometers, and Sa was 0.48 micrometers. The variation coefficient of Sv was 0.43, and the change coefficient of Sz was 0.40. The minimum value of peel strength was 7.0 N / 50 mm, and the maximum value exceeded 10 N / 50 mm, and could not be measured.

(Comparative example 2)
A 50 μm thick PET film was used as a transfer film. The surface of the insulating protective layer after peeling off the transfer film was a glossy surface. Sv on the insulation protective layer formation surface of the transfer film was 0.8 μm, Sz was 1.3 μm, and Sa was 0.06 μm. The variation coefficient of Sv was 0.23, and the change coefficient of Sz was 0.13. The minimum value of peel strength was 0.08 N / 50 mm, the maximum value was 0.15 N / 50 mm, and the average value was 0.10 N / 50 mm.

  Table 1 summarizes the results of each example and comparative example. In addition to Sv and Sz, sharpness (Sku), minimum autocorrelation length (Sal), aspect ratio of surface quality (Str), height of protruding valley (Svk) and load for separating protruding valley and core Data are also described for the area ratio (Smr2).

  The electromagnetic wave shielding film of the present disclosure can easily peel off the transfer film, and can improve the productivity.

101 electromagnetic wave shield film 102 printed wiring board 103 shield wiring board 111 conductive adhesive layer 112 insulation protection layer 113 shield layer 115 transfer film 121 insulation film 122 base member 123 adhesive layer 125 ground circuit

Claims (2)

An insulating protective layer,
A transfer film releasably provided on the surface of the insulating and protective layer;
And a conductive adhesive layer provided on the side opposite to the transfer film of the insulating protective layer,
The surface on the insulating protective layer side of the transfer film has a maximum valley depth (Sv) of 1 μm or more and 5 μm or less, and a maximum height (Sz) of 2 μm or more and 9 μm or less , a minimum autocorrelation length (Sal) Is an electromagnetic wave shielding film of not less than 8.5 μm and not more than 20 μm . The electromagnetic wave shielding film according to claim 1, wherein the variation coefficient of the maximum valley depth (Sv) and the variation coefficient of the maximum height (Sz) in the surface on the insulating protective layer side of the transfer film are 0.2 or less. .

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