JP2015179790A - Laminate for electromagnetic wave shield, electronic apparatus, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus that has high reliability of electromagnetic wave shielding property and can be reduced in size, a method for manufacturing the electronic apparatus, and a laminate for electromagnetic wave shield.SOLUTION: A laminate 27 for electromagnetic wave shield is used to ground a ground circuit 13 formed on a substrate 11 to an earth part 41 of an electronic apparatus. The laminate 27 comprises stacked layers of at least: a conductive adhesive layer 25 containing a conducive filler and a binder resin that thermally softens, to be converted into an electromagnetic shield layer 21 by thermal press-bonding; and a patterned insulating layer 22. The laminate 27 is adapted to form such a structure that: the electromagnetic wave shield layer 21 and the patterned insulating layer 22 formed by using a photosensitive resin layer are stacked in this order on an insulating protective film 15; the electromagnetic wave shield layer 21 and the ground circuit 13 are electrically connected via an opening 16 provided in the insulating protective film 15; and the electromagnetic wave shield layer 21 and the earth part 41 are electrically connected via an opening pattern 23 provided in the patterned insulating layer 22.

Description

  The present invention relates to an electromagnetic wave shielding laminate. The present invention also relates to an electronic device using the laminate for electromagnetic wave shielding and a method for manufacturing the same.

  Various electronic devices such as portable terminals, PCs, servers, and the like incorporate a substrate such as a flexible printed wiring board. These substrates are usually provided with an electromagnetic shielding structure in order to prevent malfunctions due to external magnetic fields and radio waves and to reduce unnecessary radiation from electrical signals.

  In patent document 1, the structure which provides the shield layer by which the cover film, the metal thin film layer, and the adhesive bond layer were laminated | stacked in this order is disclosed as a shield film used for a shield flexible printed wiring board. One end of this shield film is provided with conductive bumps, protrusions or metal fillers that are pressed against the cover film so as to be electrically connected to the above-mentioned shield layer, and are exposed in the vicinity of the other end. The structure which provides the ground member formed so that connection to the ground part of this is possible is disclosed. Moreover, a window part is provided on the cover film of the shield film by an excimer laser, a ground member is connected to the window part via a conductive adhesive, and the other end of the ground member is connected to a nearby ground part. A structure is disclosed.

  In Patent Document 2, as shown in FIG. 8, a flexible flat cable 110 in which a signal conductor 111 and a ground conductor 112 are formed on a base film 114 and covered with an insulating film 113 is sandwiched between shield films 120, A structure in which one of the shield films 120 is thermocompression bonded to a conductive member 130 connected to an external ground member has been proposed. The conductive member 130 includes a metal layer (not shown) for connection to an external ground member and a conductive adhesive layer 133 including conductive particles 135 in contact. The shield film 120 is composed of a laminate of an adhesive layer 121, an intervening layer 122, an adhesive layer 123, a metal thin film layer 124, and a cover film 125. When the conductive member 130 is thermocompression bonded to the shield film 120, the conductive particles 135 break through the cover film 125, and the conductive member 130 and the shield film 120 are electrically connected. The ground conductor 112 of the flexible flat cable 110 is connected to an external ground member such as a housing of an electronic device to be incorporated, and the ground conductor 112 and the conductive member 130 are at the same ground potential.

Japanese Patent No. 3434021 JP 2011-66329 A

  With the recent increase in signal speed and light and thin devices, the distance between wires has become narrower, and the technology to effectively prevent electromagnetic interference (Electro Magnetic Interference (EMI)) and electromagnetic compatibility (Electromagnetic Compatibility ( EMC)) is required.

  In the shield film of Patent Document 1, since conductive bumps, protrusions, or metal fillers that are pressed against the cover film and penetrate the cover film are provided, the film thickness of the cover film, the size of the metal filler, the bonding conditions, etc. are precise. There was a problem in reliability. In the method using an excimer laser, it is necessary to provide a metal layer so as not to cause defective opening of the window, and the irradiation condition is set so that the metal layer provided in the lower layer and the opening are not formed in the lower layer. It was necessary to control precisely. Also in the shield wiring board of Patent Document 2, it is necessary to make the layer thickness L1 thinner than the average protruding length L2 of the conductive particles 135, the particle size of the conductive particles 35, the thermocompression bonding conditions, the thickness of the cover film 125. Etc. had to be precisely controlled, and there was a problem in reliability. In addition, it is necessary to secure a structure and a region for connecting the ground conductor 112 of the flexible flat cable 110 to the external housing.

  The present invention has been made in view of the above-mentioned background, and its object is to provide an electronic device with high reliability of electromagnetic wave shielding and capable of realizing miniaturization, a method for manufacturing the electronic device, and an electromagnetic wave shielding device. It is to provide a laminate.

  As a result of extensive studies by the present inventors, it has been found that the problems of the present invention can be solved in the following modes, and the present invention has been completed.

  An electromagnetic wave shielding laminate according to the present invention is an electromagnetic wave shielding laminate for grounding a ground circuit formed on a substrate to an earth portion formed in a main body of an electronic device, and includes the ground circuit. A laminated body for electromagnetic wave shielding disposed between the substrate on which a circuit pattern and an insulating protective film for insulating and protecting the circuit pattern are formed, and the grounding part formed on the main body, on the insulating protective film An insulating layer with a pattern formed using an electromagnetic wave shielding layer and a photosensitive resin layer is laminated in this order, and the electromagnetic wave shielding layer and the ground circuit are electrically connected through an opening provided in the insulating protective film; and A bar softened by heat so that the electromagnetic shielding layer and the grounding portion are electrically connected through an opening pattern provided in the patterned insulating layer. A Nda resin containing a conductive filler, a conductive adhesive layer which functions as the electromagnetic wave shielding layer by thermocompression, and the patterned insulating layer is obtained by at least laminated.

  An electronic apparatus according to the present invention is an electronic apparatus in which a substrate with an electromagnetic wave shielding layer is bonded to a main body, and a circuit pattern including a ground circuit and an insulating protective film for insulating and protecting the circuit pattern on the substrate And an electromagnetic wave shielding layer that is laminated on the insulating protective film, is electrically connected to the ground circuit through an opening provided in the insulating protective film, and shields the circuit pattern, and is formed on the electromagnetic wave shielding layer. And a patterned insulating layer formed using a photosensitive resin layer, and a conductive member formed at least in the opening pattern of the patterned insulating layer. The main body is formed with an earth portion that is electrically connected to the conductive member and is grounded to the ground circuit. The electromagnetic wave shielding layer includes a binder resin that is softened by heat, and a conductive filler. It includes at least a layer formed by thermocompression bonding of a conductive adhesive layer containing.

  A method for manufacturing an electronic device according to the present invention is a method for manufacturing an electronic device in which a substrate with an electromagnetic wave shielding layer is bonded to a main body, wherein the circuit pattern is formed on a substrate on which a circuit pattern including a ground circuit is formed. Protecting, forming an insulating protective film having an opening on at least a part of the ground circuit, and forming a photosensitive adhesive composition using a conductive adhesive layer containing a binder resin and a conductive filler, and a photosensitive resin composition At least a resin layer is laminated, an actinic ray is irradiated to a predetermined position of the photosensitive resin layer, and an exposed pattern is formed by removing an exposed portion or an unexposed portion to obtain a patterned insulating layer, An electromagnetic wave shielding laminate comprising the conductive adhesive layer and the patterned insulating layer is obtained, and the conductive adhesive layer is on the lower protective layer so that the conductive adhesive layer is on the lower layer side. After placing, the electromagnetic wave shielding laminate is thermocompression-bonded, a conductive member is provided in the opening pattern, and the substrate is joined to the main body so as to electrically connect the conductive member to the ground portion of the main body. It is.

According to the present invention, the ground connection structure is provided in the thickness direction of the substrate, and the ground connection between the substrate and the main body is realized by the conductive path in the thickness direction of the substrate. In addition, by establishing a ground connection with the main body through a conductive path in the thickness direction of the substrate, the degree of freedom in designing the arrangement of the ground circuit in the substrate can be increased. In addition, a large number of ground circuits can be formed in the substrate, and the electromagnetic wave shielding effect can be improved more effectively.
ADVANTAGE OF THE INVENTION According to this invention, there exists an outstanding effect that the reliability of electromagnetic wave shielding property is high, and the electronic device which implement | achieves size reduction, its manufacturing method, and the laminated body for electromagnetic wave shielding can be provided.

The typical sectional view of the important section of the electronic equipment with an electromagnetic wave shield layer concerning a 1st embodiment. Sectional drawing of the manufacturing process of the laminated body for electromagnetic wave shielding which concerns on 1st Embodiment. The typical sectional view of the layered product for electromagnetic wave shielding concerning a 1st embodiment. Manufacturing process sectional drawing of the electronic device with an electromagnetic wave shield layer which concerns on 1st Embodiment. The typical sectional view of the important section of the electronic equipment with an electromagnetic wave shield layer concerning a 2nd embodiment. Typical sectional drawing of the principal part of the electronic device with an electromagnetic wave shield layer which concerns on 3rd Embodiment. Typical sectional drawing of the principal part of the electronic device with an electromagnetic wave shield layer which concerns on 4th Embodiment. The typical sectional view of the important section of the shield wiring board concerning a conventional example.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. In addition, the size and ratio of each member in the following drawings are for convenience of explanation, and are not limited to this.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view of a main part of the electronic device according to the first embodiment. The electronic device 1 is obtained by bonding a substrate with an electromagnetic wave shielding layer of an electronic device to a main body, and includes a circuit board 10, an electromagnetic wave shielding laminate 20, a main body 40, and the like as shown in FIG.

  The circuit board 10 includes a substrate 11 on which a circuit pattern 14 such as a signal circuit 12 and a ground circuit 13 is formed, and an insulating protective film (coverlay) 15 covering the upper layer of these. The substrate 11 is not particularly limited as long as it conforms to the gist of the present invention, and can be widely applied to a rigid substrate, a flexible substrate, a rigid flexible substrate, and the like. The formation method of the circuit pattern 14 is not specifically limited, A well-known method can be utilized.

  When a flexible printed circuit board is used as the substrate 11, for example, a structure in which an insulating base film having a thickness of about 5 to 100 μm and a circuit pattern 14 having a thickness of about 5 to 100 μm are bonded via an adhesive layer can be used. The material of the insulating base film is not particularly limited, and examples thereof include resins such as polyimide, polyamide, polyamideimide, polyetherimide, polybenzoxazole, polyethylene terephthalate, polyethylene naphthalate, polypropylene, and polyphenylene sulfide. The substrate 11 may be used in a bent state or the like.

  When a rigid substrate is used as the substrate 11, for example, a glass epoxy substrate, a glass composite substrate, a Teflon (registered trademark) substrate, a ceramic substrate, and the like can be given. An electronic element including an active element connected to the signal circuit 12 may be mounted on the substrate 11.

  The material of the circuit pattern 14 is not particularly limited, and examples thereof include metals such as Cu, Al, Au, Ag, Ni, Pd, Sn, Cr, W, Fe, Ti, and SUS materials, and conductive materials such as alloys thereof. The ground circuit 13 may be formed at any location as long as an earth contact can be made with the ground portion 41 provided on the electromagnetic wave shielding layer 21 and the main body 40, and may be inside the substrate or the back surface of the substrate in addition to the surface of the substrate 11. The same applies to the formation position of the signal circuit 12.

  The insulating protective film 15 is not particularly limited as long as it has a role of protecting the circuit pattern 14, has an insulating property, and can withstand a thermocompression bonding process described later. Preferable examples include inorganic material films such as silicon oxide, silicon nitride, and nitrogen-containing silicon oxide, or organic material films such as polyimide resin and polybenzoxazole resin. A photosensitive resin composition containing a resin such as a polyimide precursor or a polybenzoxazole precursor, a photopolymerizable compound, a photopolymerization initiator, or the like may be used. The insulating protective film 15 may be a single layer, or a plurality of the same or different layers may be laminated. The insulating protective film 15 is provided with an opening 16 as an opening pattern in an upper layer of the ground circuit 13.

  The electromagnetic wave shielding laminate 20 is composed of a layer in which an electromagnetic wave shielding layer 21 and a patterned insulating layer 22 are at least laminated. The electromagnetic wave shielding laminate 20 is obtained by thermocompression bonding after laminating an electromagnetic wave shielding laminate 27 (see FIG. 3) described later on the insulating protective film 15. Between the electromagnetic wave shielding layer 21 and the patterned insulating layer 22, a single conductive layer or a plurality of conductive layers such as a metal foil may be laminated. In this case, the conductive adhesive layer may use an anisotropic conductive adhesive that exhibits conductivity anisotropically in the Z-axis direction. The electromagnetic wave shielding layer 21 of the first embodiment is composed of a layer obtained by thermocompression bonding of a conductive adhesive layer formed by thermocompression bonding with a binder resin softened by heat and a conductive adhesive layer containing a conductive filler.

  The electromagnetic wave shielding layer 21 serves to prevent electromagnetic waves generated from the circuit pattern 14 from leaking to the outside and to shield electromagnetic waves (noise) from the outside to the circuit. The electromagnetic wave shielding layer 21 is electrically connected to the ground circuit 13 through the opening 16 of the insulating protective film 15.

  The electromagnetic wave shielding layer 21 according to the first embodiment is made of a layer obtained by thermocompression bonding of a conductive adhesive layer having a shielding effect. By thermocompression bonding, the electromagnetic wave shielding layer 21 can be bonded to the ground circuit 13 and the insulating protective film 15, and the ground circuit 13 and the electromagnetic wave shielding layer 21 can be made conductive. The formation position of the electromagnetic wave shielding layer 21 is preferably disposed opposite the formation area of the circuit pattern 14 from the viewpoint of effectively exhibiting the shielding characteristics. From the viewpoint of preventing radiation and intrusion of electromagnetic waves from the end direction of the circuit pattern 14, it is more preferable to form the electromagnetic wave shielding layer 21 in a range wider than the formation area of the circuit pattern 14. However, the electromagnetic wave shielding layer 21 may not be disposed so as to face the entire formation region of the circuit pattern 14 depending on the application.

  The patterned insulating layer 22 is a layer formed using a photosensitive resin layer and has an opening pattern 23. By providing the patterned insulating layer 22 between the electromagnetic wave shielding layer 21 and the ground portion 41, the electromagnetic wave shielding layer can be insulated and protected from being short-circuited when in contact with other conductive members. The shape of the opening pattern 23 in a top view is not particularly limited, and examples thereof include a square shape, a rectangular shape, and a circular shape with each side of 1 μm to 15 mm.

  The conductive member 33 is not particularly limited as long as a conductor is formed so that the electromagnetic wave shielding layer 21 and the ground portion 41 are electrically connected. In the example of FIG. 1, the plating layer 31 covering the opening pattern 23 and the conductive tape 32 in contact with the plating layer 31 are configured, but the present invention is not limited to this. The conductive member 33 may be formed only by the conductive tape 32 or may be filled with a conductive paste. In addition, bumps fixed to the ground portion 41 can be brought into contact with the electromagnetic wave shielding layer 21. In addition, a conductive sheet having at least a binder resin that is softened by heat and a conductive adhesive layer containing a conductive filler is disposed over, for example, the entire surface of the opening pattern 23 or the patterned insulating layer 22, and is opened by thermocompression bonding. You may join by making it flow in the pattern 23. FIG. If there is no problem in the heat resistance of the main body 40, a conductive adhesive layer may be disposed on the patterned insulating layer 22, and the main body and the patterned insulating layer may be joined by thermocompression bonding. In this case, the conductive sheet not only functions as an adhesive, but also functions as the conductive member 33 of the opening pattern 23, and can also play a role as a ground portion provided in the main body 40.

  The main body 40 is a member that constitutes the electronic apparatus 1 and may be any member that is at least larger than the circuit board 10 and can be attached to the board. As a suitable example, a member such as a housing, a board constituting a main body arranged inside, a lid configured to be detachable can be exemplified.

  The earth part 41 formed in the main body 40 of the electronic device is a conductor part for grounding the ground circuit 13 to the main body 40 and has a ground potential. The ground portion 41 can be a conductive layer or a conductor having a predetermined shape. If the main body 40 itself is conductive, the main body itself can be used as the ground portion 41. The area where the ground portion 41 is formed preferably has a large area from the viewpoint of ensuring EMI countermeasures and design flexibility of the wiring circuit. In the first embodiment, the ground portion 41 is formed in a region wider than the region where the electromagnetic wave shielding layer is formed. The structure of the ground portion 41 can be exemplified by a structure embedded in the main body 40 and a method of forming a conductive layer in the Z-axis direction, in addition to an embodiment in which a conductive layer is formed at a position facing the electromagnetic wave shield layer 21.

Next, an example of the manufacturing method of the electronic device with an electromagnetic wave shielding layer according to the first embodiment will be described.
First, an insulating protective film 15 having an opening 16 disposed on the ground circuit 13 is formed on the substrate 11 on which the circuit pattern 14 including the ground circuit 13 is formed (step 1). . The opening 16 can be formed by, for example, a photolithography method. As another method, an insulating protective film in which the opening 16 is previously formed may be laminated.

  On the other hand, in order to form the electromagnetic wave shielding layer 21 and the patterned insulating layer 22 on the insulating protective film 15, an electromagnetic wave shielding laminate is formed. Although the formation method of the laminated body for electromagnetic wave shields is not specifically limited, The following method can be mentioned as a preferable method.

  In FIG. 2, the manufacturing process sectional drawing for manufacturing the laminated body for electromagnetic wave shields which concerns on 1st Embodiment is shown. First, a conductive adhesive layer 25 is formed on the release film 24 by coating a composition containing a binder resin that is softened by heat and a conductive filler. The conductive adhesive layer 25 may be a single layer or a plurality of layers. In the case of forming with a plurality of layers, the outermost layer on the release film 24 side is preferably composed of a layer having higher fluidity. Next, an insulating layer made of the photosensitive resin layer 26 is formed in order to obtain the patterned insulating layer 22. The material of the release film 24 is not particularly limited as long as it has releasability. For example, a PET film coated with silicone can be used.

The conductive adhesive layer 25 preferably has a flow amount of 0.005 mm or more and 2 mm or less when thermocompression bonding is performed at 150 ° C. and a pressure of 20 kg / cm ² for 30 minutes, and 0.05 mm or more and 1 mm or less. More preferably, it is 0.05 mm or more and 0.5 mm or less. By setting it in the range of 0.005 mm or more and 2 mm or less, moderate fluidity is obtained to fill the opening 16. The flow amount refers to a length that protrudes from the side surface with respect to the original size of the conductive adhesive layer 25 when the conductive adhesive layer 25 is pressure-bonded under the above conditions. The temperature and pressure in the thermocompression bonding process of this manufacturing process do not need to be performed under the conditions of 150 ° C., 20 kg / cm ² , 30 minutes, depending on the heat resistance of components such as circuits, manufacturing equipment or needs, In the range which can ensure the coating | covering property of an electromagnetic wave shield layer, it can set arbitrarily independently, respectively. It is preferable to set the temperature and pressure conditions so that a flow amount of 0.005 mm or more and 2 mm or less is obtained. The pressure range, the flow amount but is not limited, it is preferably a pressure to be obtained, preferably about 1 to 50 kg / cm ^2, about 5~30kg / cm ² is more preferable. The crimping time is preferably not limited to the time for obtaining the flow amount, but is preferably about 1 to 30 minutes. What is necessary is just to use the electroconductive sheet of the thickness from which the said flow amount is obtained as an electroconductive sheet.

  The thickness of the conductive adhesive layer 25 is set such that the opening 16 can be filled with the conductive adhesive layer 25 and can also be covered on the insulating protective film 15 in a thermocompression bonding process described later. Although it may vary depending on the fluidity of the binder resin used and the size of the opening 16, the thickness of the conductive adhesive layer 25 is usually preferably about 1 to 100 μm, more preferably about 3 to 50 μm, and about 5 to 20 μm. Further preferred. As a result, it is possible to effectively exhibit electromagnetic wave shielding properties and achieve thinning while improving the covering property to the insulating protective film 15.

  The Tg of the binder resin constituting the conductive adhesive layer 25 is preferably −20 ° C. or higher and 100 ° C. or lower, and more preferably −10 ° C. or higher and 80 ° C. or lower. One type of binder resin may be used or a plurality of types may be used in combination. In the case of using a plurality of types, it is preferable that the main component is Tg before mixing included in the above range. The material of the conductive adhesive layer 25 is not particularly limited as long as it has a flowability that softens during thermocompression bonding and follows the surface of the opening 16 and has a conductive property that can exhibit electromagnetic wave shielding properties.

  Although it does not specifically limit as binder resin in the composition which forms the electroconductive contact bonding layer 25 in the range which does not deviate from the meaning of this invention, A thermosetting resin is preferable. In applications where there is no heating step such as a reflow step in the subsequent step, a thermoplastic resin is preferred. As the thermosetting resin, a self-crosslinking type and a curing agent reaction type can be used. As the curing agent reaction type binder resin, a thermosetting resin to which a reactive functional group capable of reacting with the curing agent is bonded is preferable.

  The thermosetting resin is preferably epoxy, acrylic, urethane, polystyrene, polycarbonate, polyamide, polyamideimide, polyesteramide, polyetherester, urethane urea, polyimide, or the like. The thermosetting resin usually has a functional group capable of self-crosslinking or a functional group capable of reacting with a curing agent. Among these, in consideration of harsh conditions when manufacturing an electronic device including the electronic device 1 with an electromagnetic wave shielding layer (for example, during reflow), the thermosetting resin is an epoxy, epoxy ester, urethane, urethane urea, and It preferably contains at least one of the polyamides. Moreover, if it is the range which can endure a heating process, a thermosetting resin and a thermoplastic resin can be used together.

  The curing agent has a plurality of functional groups capable of reacting with the curable functional group. The curing agent is preferably an epoxy compound, an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound such as dicyandiamide, an aromatic diamine, or a phenol compound such as a phenol novolac resin. It is preferable that 1-50 mass parts is contained with respect to 100 mass parts of thermosetting resins, 3-30 mass parts is more preferable, and 3-20 mass parts is further more preferable.

  The thermoplastic resin is preferably polyester, acrylic, polyether, urethane, styrene elastomer, polycarbonate, butadiene, polyamide, ester amide, isoprene, cellulose, or the like. Binder resins can be used alone or in combination.

  The conductive filler in the composition forming the conductive adhesive layer is not particularly limited as long as it has conductive characteristics and can exhibit electromagnetic wave shielding properties, but metals such as gold, silver, copper, aluminum, nickel, solder, and alloys thereof Examples thereof include conductive polymers and carbon. Also suitable are silver-coated silver-coated copper fillers, particles obtained by subjecting resin particles or the like to metal plating, and the like. The conductive filler can be used alone or in combination. The shape of the conductive filler is not particularly limited, and examples thereof include a spherical shape, a flake shape, and a dendritic shape.

  The conductive filler preferably has a shape that has a particle size smaller than the thickness of the electromagnetic wave shielding layer 21 and does not easily enter the insulating protective film 15 so as not to enter the insulating protective film 15 in a thermocompression bonding process described later. For example, a spherical shape, a flake shape, a crushed elliptical shape, or the like is preferable. The average particle diameter of the conductive filler is preferably designed as appropriate according to the thickness of the electromagnetic wave shielding layer 21. Preferably, a conductive filler having an average particle diameter of 0.05 to 2 times the thickness of the electromagnetic wave shielding layer 21 is preferably used. In addition, an average particle diameter is a numerical value which averaged about 10-20 from the enlarged image (for example, 1000 times-10,000 times) of the scanning electron microscope. When the length of the conductive filler is greatly different between the length direction and the lateral direction (when the aspect ratio is 1.5 or more), the average particle diameter is calculated in the length direction.

  The content of the conductive filler is only required to ensure the conductivity of the electromagnetic wave shielding layer 21 and may vary depending on the shape and type of the conductive filler used. However, the content of the conductive filler is 30 to 100% by mass with respect to 100 parts by mass of the binder resin. Is preferable, and 40 to 90 mass% is more preferable. By setting it as this range, the effect that it becomes easy to make electromagnetic shielding property and flow property compatible is acquired.

Furthermore, the composition constituting the conductive adhesive layer may contain a colorant, a flame retardant, an inorganic additive, a lubricant, an antiblocking agent, and the like.
Examples of the colorant include organic pigments, carbon black, ultramarine blue, petals, zinc white, titanium oxide, and graphite.
Examples of the flame retardant include a halogen-containing flame retardant, a phosphorus-containing flame retardant, a nitrogen-containing flame retardant, and an inorganic flame retardant.
Examples of the inorganic additive include glass fiber, silica, talc, and ceramic.
Examples of the lubricant include fatty acid esters, hydrocarbon resins, paraffin, higher fatty acids, fatty acid amides, aliphatic alcohols, metal soaps, and modified silicones.
Examples of the anti-blocking agent include calcium carbonate, silica, polymethylsilsesquiosan, aluminum silicate salt and the like.

  The photosensitive resin layer is a layer formed using a photosensitive resin composition. The photosensitive resin layer composition is not particularly limited as long as it can form a desired opening pattern 23 and can withstand a thermocompression bonding process described later. The photosensitive resin composition usually contains a photosensitive resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent. The photosensitive resin composition appropriately contains a binder resin, a pigment, an antifoaming agent, a flame retardant, a stabilizer, an adhesion imparting agent, a leveling agent, an antioxidant, and the like as long as not departing from the spirit of the present invention. be able to. From the viewpoint of enhancing photosensitivity, heat resistance and impact resistance, it is preferable to contain 30 to 80% by mass of the resin component with respect to the total amount of solids.

  Photosensitive resins include (meth) acryloyl group-containing acrylic resins, urethane acrylate resins, polyester acrylate resins, polyimide precursors (polyamic acid, polyamic acid ester, polyamic acid amide, etc.), polybenzoxazole precursors (polyhydroxyamide) ) And polysiloxane precursors. Among these, a polyimide precursor and a polybenzoxazole precursor are preferable because they can be thermoset without using a thermosetting agent and are excellent in heat resistance because they are imidized and oxazolated by heat treatment. By using the photosensitive resin, a cured film having excellent heat resistance, heat and humidity resistance, adhesion, mechanical properties, and the like can be obtained. The photosensitive resin can be used alone or in combination.

  The photopolymerizable compound and photopolymerization initiator are not particularly limited, but as the photopolymerizable compound, a compound having an ethylenically unsaturated group (also referred to as a (meth) acryloyl group) in the molecule is preferable.

  The photosensitive resin composition may be either a positive type or a negative type, but a negative type photosensitive resin composition is preferable from the viewpoint of many product choices. For removing the exposed or unexposed area, a method of removing the exposed area or the unexposed area using a developer such as an alkali developer or solvent development is simple. In order to impart alkali solubility, the polymer may have a functional group such as a carboxyl group, a sulfonic acid group, or a phenolic hydroxyl group.

  The thickness of the photosensitive resin layer 26 can be appropriately designed depending on the application, but from the viewpoint of insulation and thinning, the range of 1 to 50 μm is preferable, the range of 2 to 30 μm is more preferable, and the range of 3 to 20 μm is more preferable. preferable.

  A photosensitive resin composition is laminated on the conductive adhesive layer 25, and an exposed portion is formed by irradiating a predetermined position of the obtained photosensitive resin layer 26 with an actinic ray, and an exposed portion or an unexposed portion is removed. Thus, an opening pattern is formed. Then, it is preferable to perform a curing process by a thermosetting process. A thermosetting process can be performed by heat-processing for 1 minute-10 hours, for example in the temperature range of 100-250 degreeC. Thereby, the cured film with high heat resistance and heat-and-moisture resistance can be obtained. In addition, after laminating the photosensitive resin layer 26 on the conductive adhesive layer 25, when the exposure / development process is not performed immediately, after the photosensitive resin layer 26 is dried, actinic rays are irradiated on the photosensitive resin layer 26. It is preferable to laminate a light-shielding film so as not to irradiate or store in a dark place.

  After obtaining the patterned insulating layer 22 having the opening pattern 23, a release film (not shown) may be formed on the patterned insulating layer 22 from the viewpoint of easy handling at the time of thermocompression bonding described later. Through these steps, the electromagnetic wave shielding laminate 27 is obtained.

  Next, the release film 24 is peeled off, placed so that the conductive adhesive layer 25 side is in contact with the insulating protective film 15, and thermocompression bonding is performed. The thermocompression bonding can be performed by, for example, applying pressure while heating the electromagnetic shielding laminate 27 using a press machine. By performing thermocompression bonding, as shown in FIG. 4, an electromagnetic wave shielding layer 21 that covers the insulating protective film 15 is formed. The conductive adhesive layer 25 is softened by heating, and the inside of the opening 16 is filled by pressurization. By controlling the thickness, pressure, temperature, and thermocompression bonding time of the conductive adhesive layer 25, the electromagnetic wave shielding layer 21 can have a desired thickness.

The temperature and pressure at the time of thermocompression bonding can vary depending on the characteristics of the conductive adhesive layer 25 used, but the heating temperature is 100 ° C. from the viewpoint of ensuring sufficient bonding between the opening 16 and the electromagnetic wave shielding layer 21. It is preferable that it is above, More preferably, it is 110 degreeC or more, More preferably, it is 120 degreeC or more. Moreover, although it depends on the heat resistance of the circuit board 10, as an upper limit, it is preferable that it is 220 degrees C or less, It is more preferable that it is 200 degrees C or less, It is still more preferable that it is 180 degrees C or less. From the viewpoint of smoothness and production efficiency, the pressure range is preferably 1 kg / cm ² or more, more preferably 3 kg / cm ² or more, and still more preferably 5 kg / cm ² or more. Further, the upper limit value is preferably 100 kg / cm ² or less, more preferably 80 kg / cm ² or less, and 50 kg / cm ² or less from the viewpoint of pressure resistance of the circuit pattern 14 and the substrate 11. More preferably.
The thermocompression bonding time can be set according to the heat resistance of the electronic component, the binder resin used for the conductive sheet, the production process, and the like. When a thermosetting resin is used as the binder resin, a range of about 1 minute to 2 hours is preferable. The thermocompression bonding time is more preferably about 1 minute to 1 hour. The thermosetting resin is cured by this thermocompression bonding. However, the thermosetting resin may be cured before thermocompression bonding as long as it can flow.

  The thickness of the electromagnetic wave shielding layer 21 can be appropriately designed depending on the application. In the case of applications where thinning is required, for example, about 1 to 10 μm is preferable, and about 1 to 8 μm is more preferable. In addition, when shielding high-frequency noise with high accuracy, it is possible to use a thick film of, for example, 50 to 1000 μm, but it is usually about 5 to 200 μm. In addition, although an isotropic conductivity and anisotropic conductivity can be selected suitably for an electromagnetic wave shield layer, when an electromagnetic wave shield layer is comprised only from a conductive adhesive layer, what shows isotropic conductivity is preferable.

  Next, a conductive member 33 is formed in the opening pattern 23 of the patterned insulating layer 22. In the first embodiment, as the conductive member 33, first, the plating layer 31 is formed on the opening pattern 23, and then the conductive tape 32 on both sides is attached. The conductive member 33 is not limited to the above-described configuration, and various members can be used. For example, it can be provided on the entire surface of the joint portion between the opening pattern 23 and the patterned insulating layer 22 using a conductive adhesive layer.

  On the other hand, a ground portion 41 is provided at least at a joint portion of the substrate 30 with an electromagnetic wave shielding layer of a main body of an electronic device (for example, a casing of a mobile phone, a board, a lid portion of a battery, etc.) with the electromagnetic wave shielding layer. The form of the earth portion 41 is not limited as long as the ground potential can be grounded. For example, it can form with respect to the main body 40 by coating, printing, etc. of a plating layer, a metal vapor deposition film, a conductive composition. In addition, when the main body 40 itself that serves as a joint portion with the conductive member 33 functions as a ground portion, it is not necessary to provide a separate ground portion 41 in the main body 40.

  Thereafter, a substrate with an electromagnetic wave shield layer (hereinafter referred to as “substrate with a shield layer”) 30 is attached so that the conductive member 33 is connected to the ground portion 41 of the main body 40. When the conductive member 33 is provided at the position of the opening pattern 23, an adhesive layer or a pressure-sensitive adhesive layer can be laminated and bonded between the electromagnetic wave shield laminate 20 and the ground portion 41 as necessary.

  When an excimer laser is used as a method for forming an opening in an insulating layer, it is necessary to form a metal layer so that the opening is not formed below the insulating layer. Furthermore, it is necessary to precisely control the irradiation conditions of the excimer laser so as not to cause an opening defect and not to open the formed lower metal layer. For this reason, it is difficult to reduce the film thickness, and it cannot be said that the degree of freedom in design is high. In the case of a structure in which conductive fillers or metal bumps are pierced into the insulating layer without providing an opening pattern in the insulating layer to achieve conduction with the electromagnetic wave shielding layer, the thickness of the insulating layer, the size and shape of the conductive filler, etc. Therefore, it is necessary to precisely control the pressing pressure, and there is a problem in the reliability of the product. Moreover, when connecting a housing | casing by a board | substrate edge part, it was necessary to ensure the area | region of a board | substrate edge part, and had prevented the miniaturization.

  According to the first embodiment, since the circuit board and the main body are joined using the electromagnetic wave shielding laminate in which a pattern is formed in advance, the ground portion of the main body and the ground circuit are bonded via the electromagnetic shielding layer. High and reliable conduction can be achieved. The manufacturing yield of the electronic device and the circuit board can be increased as compared with the case where an opening is provided in the insulating protective film using an excimer laser or the conventional method of piercing a metal bump or the like into the insulating protective film. Therefore, a highly reliable electromagnetic wave shielding layer can be provided.

  In addition, according to the electronic apparatus with an electromagnetic wave shielding layer according to the first embodiment, since a route for allowing the ground potential to escape in the thickness direction of the substrate is adopted, an area for grounding the ground is not secured at the end of the substrate. Both can be grounded, and downsizing can be realized. It should be noted that the ground circuit is not intended to eliminate the structure of conducting at the edge of the substrate, but can be used in combination with the present invention. By using in combination with a structure in which a ground connection structure is provided at the end of the substrate, the electromagnetic wave shielding effect can be realized more effectively.

  In addition, according to the electronic device with an electromagnetic wave shielding layer according to the first embodiment, the circuit pattern, the electromagnetic wave shielding layer, and the conductive layer constituting the ground portion have a structure in which they are arranged to face each other, and a ground potential is provided. Therefore, EMI can be more effectively suppressed and EMC can be improved more effectively.

[Second Embodiment]
Next, an example of an electronic device with an electromagnetic wave shielding layer different from the first embodiment will be described. The electronic device with an electromagnetic wave shielding layer according to the second embodiment has the same basic structure and manufacturing method as the first embodiment except for the following points. That is, the electromagnetic wave shielding laminate of the second embodiment has a conductive adhesive layer obtained by thermocompression bonding in that the conductive adhesive layer is a layer of a metal layer and a metal layer laminate. This is different from the first embodiment in which only the layer is used as the electromagnetic wave shielding layer. In the following drawings, the same element members are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In FIG. 5, the typical sectional drawing of the principal part of the electronic device with an electromagnetic wave shield layer which concerns on 2nd Embodiment is shown. As for the electromagnetic wave shield laminated body 20a used for the electronic device 2, the 2nd electromagnetic wave shield layer 21Y which consists of a metal layer is formed between the 1st electromagnetic wave shield layer 21X and the insulating layer 22 with a pattern. The second electromagnetic wave shielding layer 21Y can appropriately select the material and thickness of the metal layer according to the required shielding characteristics. For example, it can be formed with a thickness of about 0.1 to 40 μm using a material such as aluminum, copper, silver, or gold. From the viewpoint of bending resistance, it is preferably in the range of 0.1 to 20 μm, and more preferably in the range of 0.1 to 10. Although the formation method of the 2nd electromagnetic wave shield layer 21Y is not specifically limited, It can form by vacuum evaporation, sputtering, CVD method, and a plating process.

  According to the electronic device with an electromagnetic wave shielding layer according to the second embodiment, since the electromagnetic wave shielding layer is laminated using the laminated body for electromagnetic wave shielding, the same effect as that of the first embodiment can be obtained. Further, by providing the second electromagnetic wave shielding layer 21Y made of a metal layer, the shielding effect can be more effectively exhibited. Moreover, since an impedance countermeasure can be exhibited more effectively, it is particularly suitable for high frequency applications.

[Third Embodiment]
Next, an example of an electronic device with an electromagnetic wave shielding layer different from the first embodiment will be described. The electronic apparatus with an electromagnetic wave shielding layer according to the third embodiment has the same basic structure and manufacturing method as those of the first embodiment except for the following points. That is, the third embodiment is different from the first embodiment in which the electromagnetic shielding laminate is bonded to both surfaces of the circuit board 10b, and the electromagnetic shielding laminate is bonded to only one surface.

  FIG. 6 is a schematic cross-sectional view of a main part of an electronic apparatus with an electromagnetic wave shielding layer according to the third embodiment. As for the board | substrate 30b with an electromagnetic wave shield layer used for the electronic device 3, the electromagnetic wave shield layer 21 and the insulating layer 22 with a pattern are laminated | stacked on both surfaces of the circuit board 10b. One conductive member 33 is connected to the ground portion 41 of the main body 40, and the other conductive member 33 is connected to the ground member 42.

  According to the electronic device with an electromagnetic wave shielding layer according to the third embodiment, since the electromagnetic wave shielding layer is laminated using the laminated body for electromagnetic wave shielding, the same effect as that of the first embodiment can be obtained. Moreover, by laminating electromagnetic wave shielding layers on both surfaces of the substrate, EMI can be more effectively suppressed and EMC can be improved more effectively.

[Fourth Embodiment]
The electronic device with an electromagnetic wave shielding layer according to the fourth embodiment has the same basic structure and manufacturing method as the first embodiment except for the following points. That is, in the fourth embodiment, a metal thin film that prevents the conductive filler contained in the electromagnetic wave shielding layer 21 from entering the insulating protective film 15 is provided on the upper surface of the circuit board 10 b, that is, on the insulating protective film 15. However, the present embodiment is different from the first embodiment in which the metal thin film is not provided.

  In FIG. 7, the typical sectional drawing of the principal part of the electronic device with an electromagnetic wave shield layer which concerns on 4th Embodiment is shown. As for the board | substrate 30c with an electromagnetic wave shield layer used for the electronic device 4, the metal thin film 18 is laminated | stacked on the uppermost surface of the circuit board 10c. The metal thin film 18 can effectively prevent the conductive filler contained in the electromagnetic wave shielding layer 21 from entering the insulating protective film 15. The metal thin film 18 can be formed on the uppermost surface of the circuit board 10c by, for example, vacuum deposition, sputtering, CVD, or plating. A metal thin film is formed before the opening 16 is formed, and the metal thin film 18 can be formed on the uppermost surface of the circuit board 10b as shown in FIG. It is also possible to form a metal thin film after forming the opening 16 and form a thin film in the uppermost surface of the circuit board 10 c and the opening 16.

  According to the electronic device with an electromagnetic wave shielding layer according to the fourth embodiment, since the electromagnetic wave shielding layer is laminated using the laminated body for electromagnetic wave shielding, the same effect as that of the first embodiment can be obtained. In addition, by providing the metal thin film 18, the metal thin film 18 can be provided with an electromagnetic wave shielding function, and the conductive filler contained in the electromagnetic wave shielding layer 21 can be effectively prevented from entering the insulating protective film 15. . As a result, it is possible to reduce the thickness of the insulating protective film 15. Moreover, it has the merit that the choice of a conductive filler can be increased. For this reason, it is also possible to use a conductive filler that is easier to obtain conductive characteristics.

[Fifth Embodiment]
The basic structure and manufacturing method of the electronic device with an electromagnetic wave shielding layer according to the fifth embodiment are the same as those of the first embodiment except for the following points. That is, in the fifth embodiment, the electromagnetic wave shielding laminate is used in that the electromagnetic shielding layer and the patterned insulating layer are formed independently on the circuit board without using the electromagnetic shielding laminate shown in FIG. This is different from the first embodiment.

  The electronic device with an electromagnetic wave shielding layer according to the fifth embodiment performs thermocompression bonding by laminating the conductive adhesive layer 25 on the upper layer of the circuit board 10, that is, the insulating protective film 15. Thereby, the electromagnetic wave shielding layer 21 is obtained. Next, if necessary, a second electromagnetic wave shielding layer made of a metal layer may be formed on the upper layer. Thereafter, a photosensitive resin layer is coated on the electromagnetic wave shielding layer, an exposure / development process is performed, and a patterned insulating layer 22 is obtained through a heat curing process as necessary. The subsequent steps are the same as those in the first embodiment.

  According to the method for manufacturing an electronic device with an electromagnetic wave shielding layer according to the fifth embodiment, the same effects as those of the first embodiment can be obtained. Moreover, it has the merit that a pattern formation and joining to a circuit board can be performed continuously from the coating film of the photosensitive resin layer.

  It goes without saying that other embodiments may belong to the category of the present invention as long as they match the gist of the present invention. Moreover, the said embodiment is mutually combined suitably.

1-4 Electronic equipment 10 Circuit board 11 Board 12 Signal circuit 13 Ground circuit 14 Circuit pattern 15 Insulating protective film (cover lay)
DESCRIPTION OF SYMBOLS 16 Opening part 17 Via 18 Metal thin film 20 Electromagnetic wave shielding laminated body 21 Electromagnetic wave shielding layer 22 Insulating layer 23 Opening pattern 24 Release film 25 Conductive adhesive layer 26 Photosensitive resin layer 27 Laminated body 30 for electromagnetic wave shielding layer 31 with electromagnetic wave shielding layer Plating layer 32 Conductive tape 33 Conductive member 40 Main body 41 Ground portion 42 Ground member

Claims (8)

An electromagnetic wave shielding laminate for grounding a ground circuit formed on a substrate to an earth part formed on a main body of an electronic device,
A laminated body for electromagnetic wave shielding arranged between the circuit pattern including the ground circuit and the substrate on which the insulating protective film for insulating and protecting the circuit pattern is formed, and the earth portion formed on the main body,
A patterned insulating layer formed using an electromagnetic wave shielding layer and a photosensitive resin layer is laminated in this order on the insulating protective film, and the electromagnetic wave shielding layer and the ground are disposed through an opening provided in the insulating protective film. The circuit is conductive, and the electromagnetic shielding layer and the grounding part are electrically connected through an opening pattern provided in the patterned insulating layer.
A laminate for electromagnetic wave shielding, comprising a binder resin that is softened by heat, a conductive filler, and a conductive adhesive layer that functions as the electromagnetic wave shielding layer by thermocompression bonding, and the patterned insulating layer.   The laminate for electromagnetic wave shielding according to claim 1, wherein the electromagnetic wave shielding layer is further laminated with a metal layer on the conductive adhesive layer. An electronic device in which a substrate with an electromagnetic wave shielding layer is bonded to the main body,
On the substrate,
A circuit pattern including a ground circuit;
An insulating protective film for insulating and protecting the circuit pattern;
An electromagnetic wave shielding layer that is laminated on the insulating protective film, is electrically connected to the ground circuit via an opening provided in the insulating protective film, and shields the circuit pattern;
A patterned insulating layer formed on the electromagnetic shielding layer and formed using a photosensitive resin layer;
A conductive member formed at least in an opening pattern of the patterned insulating layer;
The body is electrically connected by being joined to the conductive member, and an earth portion for grounding the ground circuit is formed,
The electromagnetic wave shielding layer is an electronic device including at least a layer formed by thermocompression bonding of a binder resin that is softened by heat and a conductive adhesive layer containing a conductive filler.   The electronic device according to claim 3, wherein the electromagnetic wave shielding layer further includes a metal layer laminated on an upper layer formed by thermocompression bonding the conductive adhesive layer. A method of manufacturing an electronic device in which a substrate with an electromagnetic wave shielding layer is bonded to a main body,
On the substrate on which a circuit pattern including a ground circuit is formed, the circuit pattern is protected, and an insulating protective film having an opening is formed on at least a part of the ground circuit,
At least a conductive adhesive layer containing a binder resin and a conductive filler and a photosensitive resin layer formed using the photosensitive resin composition are laminated, and an actinic ray is irradiated to a predetermined position of the photosensitive resin layer. Then, an exposed layer or an unexposed portion is removed to form an opening pattern to obtain a patterned insulating layer, and to obtain an electromagnetic wave shielding laminate comprising at least the conductive adhesive layer and the patterned insulating layer,
After placing on the insulating protective film so that the conductive adhesive layer is on the lower layer side, the electromagnetic shielding laminate is thermocompression bonded,
A conductive member is provided in the opening pattern,
The manufacturing method of the electronic device which joins the said board | substrate to the said main body so that the said electrically-conductive member may be electrically connected to the earth | ground part of the said main body.   The method for manufacturing an electronic device according to claim 5, wherein the opening pattern of the patterned insulating layer is plated.   The method of manufacturing an electronic device according to claim 5, wherein a conductive tape is disposed in the opening pattern of the patterned insulating layer.   The manufacturing method of the electronic device of any one of Claims 5-7 which laminates | stacks a metal layer on the upper layer of the said electroconductive contact bonding layer, and forms a photosensitive resin layer after that.

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