KR20190067112A - Reinforcing member for printed wiring board - Google Patents

Abstract

The objective of the present invention is to realize a reinforcing plate (100) for a wiring board in which an increase in a connection resistance after reflow is suppressed. To this end, according to the present invention, the reinforcing plate for a wiring board (100) comprises: a reinforcing plate main body (101); and a first conductive adhesive layer (102) installed on a first surface (101A) of the reinforcing plate main body (101). An aspect ratio of the surface property on the first surface (101A) of the reinforcing plate main body (101) is higher than equal to 0.5.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing plate for a wiring board,

The present disclosure relates to a reinforcing plate for a wiring board.

2. Description of the Related Art As miniaturization of electronic devices has progressed, the use of flexible flexible printed wiring boards (FPCs) has spread. Since the FPC is thin and has high flexibility, a reinforcing plate for a wiring board having a thin plate made of stainless steel or the like is bonded to secure the strength required for mounting.

On the other hand, electronic devices are susceptible to electromagnetic waves, and shielding of electromagnetic waves is an important issue. For this reason, by using a conductive adhesive for bonding the wiring board reinforcing plate and conducting a ground potential or the like of the reinforcing plate for the wiring board and the ground circuit or the housing of the FPC, And so on. As such a reinforcing plate for a wiring board, a metal plate such as stainless steel is used. However, on the surface of a metal plate made of stainless steel or the like, there is a case where a barrier film is formed and the connection stability between the FPC and the reinforcing plate is impaired. In order to solve such a problem, a reinforcing plate for a wiring board in which Ni plating or Au plating is applied to the surface is known (see, for example, Patent Document 1).

International Publication No. 2014/132951

However, if plating is performed on the surface of the reinforcing plate for a wiring board, the cost is increased. On the other hand, in order to suppress the cost, if a reinforcing plate for a wiring board having a sidewall coating film on its surface without being subjected to a plating treatment is to be connected to a ground circuit of the FPC, the connection resistance value is raised after reflow, And the connection stability with the ground potential is lowered.

Such a problem is not limited to stainless steel, but may occur when a metal plate having a passive film is used for a wiring board reinforcing plate.

An object of the present invention is to realize a reinforcing plate for a wiring board in which an increase in connection resistance after reflow is suppressed without performing a plating treatment or the like.

One aspect of the reinforcing plate for a wiring board of the present disclosure includes a reinforcing plate main body and a first conductive adhesive layer provided on the first surface of the reinforcing plate main body and has a surface property on the first surface of the reinforcing plate main body, Is 0.5 or more.

In one aspect of the reinforcing plate for a wiring board, the arithmetic average height on the first surface of the reinforcing plate body may be 0.10 占 퐉 or more.

The reinforcing plate main body may be made of an austenitic stainless steel.

In one embodiment of the reinforcing plate for a wiring board, the first conductive adhesive layer may be in direct contact with the first surface of the reinforcing plate main body.

One aspect of the reinforcing plate for a wiring board may further comprise a conductive adhesive layer and a plating layer provided between the reinforcing plate main body.

In this case, the plating layer may be a nickel-phosphorus plating layer.

One aspect of the reinforcing plate for a wiring board further includes a second conductive adhesive layer provided on the second surface of the reinforcing plate body and the aspect ratio of the surface property on the second surface of the reinforcing plate body is set to 0.5 or more .

One aspect of the reinforcement wiring board of the present disclosure includes a wiring board having a ground circuit and a reinforcing plate for wiring boards of the present disclosure attached to the wiring board so that the ground circuit and the metal plate are made conductive.

According to the reinforcing plate for a wiring board of the present disclosure, the increase in connection resistance after reflow can be suppressed without performing a plating treatment or the like.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view showing a reinforced wiring board using a reinforcing plate for a wiring board according to an embodiment; FIG.
2 is a cross-sectional view showing a modified example of a reinforcing plate for a wiring board.
3 is a cross-sectional view showing a modified example of a reinforcing plate for a wiring board.
4 is a cross-sectional view showing a modified example of a reinforcing plate for a wiring board.

As shown in Fig. 1, the reinforcing plate 100 for a wiring board according to the present embodiment is fixed to a wiring board 200, and a reinforcing wiring board 300 can be formed. The reinforcing plate 100 for a wiring board in the present embodiment has a reinforcing plate main body 101 made of stainless steel or the like and a conductive adhesive layer 102 provided on the first surface 101A of the reinforcing plate main body 101 . In this embodiment, the wiring board 200 is a flexible printed wiring board (FPC), and includes a base member 201 and an insulating film 203 adhered to the base member 201 by an adhesive layer 202 Have. The insulating film 203 is provided with an opening for exposing the ground circuit 205.

Since the conductive adhesive layer 102 is filled in the opening of the insulating film 203 and connected to the ground circuit 205, the ground circuit 205 and the reinforcing plate main body 101 are electrically connected through the conductive adhesive layer 102 do.

The reinforcing plate main body 101 has an aspect ratio Str of the surface property at the first surface 101A in contact with the conductive adhesive layer 102 of 0.5 or more. By setting the Str of the first surface 101A at 0.5 or more, it is possible to keep the connection resistance low even if a metal plate on which a plating treatment or the like is not performed and which has a sidewall coating film on its surface is used as the reinforcing plate main body 101 .

Str is a parameter indicating the direction dependence of the surface property and takes a value of 0 to 1. As the value approaches 1, the direction dependence of the surface property becomes smaller. In the case where linear unevenness is provided in one direction as in hairline processing, Str is almost zero even on a surface having a large arithmetic average height Sa. If the value of Str is small, the connection resistance increases greatly after reflow even if the connection resistance before reflow is low. On the other hand, when the value of Str is 0.5 or more, preferably 0.6 or more, and more preferably 0.7 or more, the connection resistance before reflow can be made low and the connection resistance can be maintained even after reflowing. Respectively. The value of Str is preferably large, and a value close to 1.0 can stabilize the connection resistance, and the value of Str may be set to 1.0 or less. However, the maximum value from the viewpoint of productivity of the wiring board reinforcing plate is less than 1.0, Is less than 0.99. The Str can be measured in accordance with ISO 25178 as described in the embodiment.

The connection resistance after the reflow changes depending on the size of the opening for connection with the ground circuit and the like. When the diameter of the opening is 1.0 mm, the connection resistance is preferably 0.5 Ω / 1 hole or less, more preferably 0.3 Ω / 1 hole or less, more preferably 0.2? / 1 hole or less. The connection resistance can be measured by the method described in the embodiment.

If Str is larger than the predetermined value, the value of Sa is irrelevant, but by setting the value of Sa to 0.10 탆 or more, more preferably 0.15 탆 or more, the connection resistance can be more stabilized. Sa can be measured in accordance with ISO 25178 as described in the embodiment.

As shown in Fig. 2, the reinforcing plate main body 101 may be provided with a plating layer 105 on the surface of the metal plate 101a. By providing the plating layer 105, the connection resistance can be more stabilized. In this case, the value of Str may be set to a predetermined range on the surface of the reinforcing plate main body 101 after the plating layer 105 is provided. The plating layer 105 can be formed by immersing the metal plate 101a in a plating bath. In this case, as shown in Fig. 3, a plating layer 105 may be provided on both surfaces of the metal plate 101a. However, a plating layer 105a may be provided on only one side of the metal plate 101a using a resist film or the like.

As the conductive reinforcing plate 101, the surface of the metal plate subjected to the surface resistance reduction treatment may be used. By performing the surface resistance reducing process, the connection resistance can be further reduced. As the surface resistance lowering treatment, for example, a treatment for containing ions which become carriers such as lithium ions in the passive film can be used. As such a treatment, there is a L-core treatment of Japan Metal Corporation. From the viewpoint of the connection resistance, it is preferable to form the plating layer and the surface resistance reduction treatment, but it is preferable that this treatment is not performed from the viewpoint of cost. In the case of performing the surface resistance reducing treatment, the value of Str on the surface of the reinforcing plate main body 101 after the surface resistance reducing treatment or the like is performed may be set in a predetermined range. The surface resistance reduction treatment may be performed on both sides of the metal plate 101a, or may be performed only on one side.

As the metal plate used for the reinforcing plate main body 101, a material in which a porous membrane is formed on the surface can be used. By setting the value of Str larger than the predetermined value, it is possible to maintain a low connection resistance even when a material that forms a passive film on the surface is used. As a material for forming the electrolyte-containing film on the surface, for example, a conductive material including stainless steel, nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium and zinc can be used.

As the metal plate 101 used for the reinforcing plate main body 101, a non-magnetic (austenitic) stainless steel or the like can be used. The reinforcing plate main body 101 using non-magnetic austenitic stainless steel or the like can reduce the influence of the wiring board reinforcing plate 100 on the motor. Various motors are used in electronic devices such as lens control of a camera, vibration function of a smart phone, pickup control of a disk drive, and the like. Since the motor and the control circuit are arranged close to each other due to the miniaturization of the electronic apparatus, there arises a problem that the motor malfunctions due to the magnetic reinforcing plate.

When the metal plate 101 is a non-magnetic austenitic stainless steel, the metal plate 101 itself can be hard to magnetize. However, in order to reduce the connection resistance, when the plating layer 105 made of a magnetic material such as nickel is provided on the surface of the metal plate 101, the reinforcing plate 100 for the wiring board is magnetized by the plating layer 105.

By using an austenitic stainless steel plate having a large Str value on the surface as the metal plate 101, it is possible to maintain a low connection resistance without forming the plating layer 105, and therefore, The reinforcing plate 100 for a wiring board can be realized.

However, in applications in which magnetism is a problem, a plating layer 105 made of a non-magnetic material can be formed. As the non-magnetic plated layer 105, for example, a nickel-phosphorus (Ni-P) plated layer and a noble metal plated layer may be used. It is also possible to perform surface resistance reduction processing.

As the austenitic stainless steel, SUS304, SUS316, SUS316L, etc. having permeability of 1.02 or less can be used. From the viewpoint of magnetism, SUS316 which is difficult to increase the permeability at the time of processing is preferable, and SUS316L having a low carbon content is more preferable.

The thickness of the metal plate 101 is not particularly limited, but is preferably 0.05 mm or more, more preferably 0.1 mm or more, preferably 1.0 mm or less, and more preferably 0.6 mm or less from the viewpoint of reinforcement.

Str of the metal plate 101 can be adjusted by performing surface roughening treatment in at least two directions. In the case of hair-line processing of a roll-to-roll normally performed, it is difficult to increase Str even if Sa can be increased as one-directional roughening. On the other hand, for example, it is possible to enlarge Str by using both the roll provided with the concavo-convex extending in the first direction and the roll provided with the concavo-convex extending in the second direction intersecting the first direction.

The conductive adhesive layer 102 may contain a binder resin and a conductive filler. The binder resin is not particularly limited and various resins used for the conductive adhesive can be used. Examples of such resins include thermoplastic resins such as polystyrene type, vinyl acetate type, polyester type, polyethylene type, polypropylene type, polyamide type, rubber type and acrylic type; phenol type, epoxy type, urethane type, melamine type , And alkyd-based thermosetting resins.

The binder resin may contain, as optional components, a defoaming agent, an antioxidant, a viscosity adjusting agent, a diluent, an anti-settling agent, a leveling agent, a coupling agent, a colorant, and a flame retardant.

The conductive adhesive of the present embodiment can be applied to a base layer (base layer) such as a release film to form a conductive adhesive layer. Further, it is also possible to prepare a conductive adhesive containing a solvent, apply it, and heat dry it to remove the solvent. The solvent may be, for example, toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol, and dimethylformamide. The ratio of the solvent in the conductive adhesive may be appropriately set depending on the thickness of the conductive adhesive layer and the like.

The conductive filler is not particularly limited, and for example, a metal filler, a metal-coated resin filler, a carbon filler, and a mixture 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 electrolytic method, an atomization method, a reduction method, or the like. Among them, any one of silver powder, silver-coated copper powder and copper powder is preferable.

The conductive filler has an average particle diameter of preferably 1 mu m or more, more preferably 3 mu m or more, preferably 50 mu m or less, and more preferably 40 mu m or less, from the viewpoint of contact between the fillers. The shape of the conductive filler is not particularly limited and may be a spherical shape, a flake shape, a resin (dendrite) shape, a fiber shape, or the like. From the viewpoint of reducing the connection resistance with the reinforcing plate main body 101, it is preferable that the dendrite type is used.

The content of the conductive filler is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 95% by mass or less, further preferably 90% by mass or less, Or less. From the viewpoint of the filling property, it is preferably not more than 70% by mass, more preferably not more than 60% by mass. In the case of realizing anisotropic conductivity, it is preferably 40 mass% or less, more preferably 35 mass% or less.

The reinforcing plate 100 for a wiring board can be manufactured, for example, as follows. First, a conductive adhesive agent is coated on a release substrate (separate film) to form a conductive adhesive layer 102. Next, the conductive adhesive layer 102 and the metal plate 101 are pressed and brought into close contact with each other. The release substrate may be peeled off before use.

As the release substrate, a silicone or non-silicone release agent coated on the surface of the side where the conductive adhesive layer 102 is formed may be used on a base film such as polyethylene terephthalate, polyethylene naphthalate or the like. The thickness of the peeling base material is not particularly limited, and can be appropriately determined in consideration of ease of use.

The thickness of the conductive adhesive layer 102 is preferably 15 m to 100 m. When the thickness is 15 mu m or more, sufficient filling property is realized and sufficient connection with the ground circuit is obtained. When the thickness is 100 占 퐉 or less, it is possible to meet the demand for thinning, and it is advantageous in terms of cost.

The base member 201 of the wiring board 200 may be made of, for example, a resin film or the like. Specifically, a base member 201 of the wiring board 200 may be formed of a material such as polypropylene, crosslinked polyethylene, polyester, polybenzimidazole, polyimide, A film made of a resin such as polyetherimide, polyphenylene sulfide, or the like.

Although the insulating film 203 is not particularly limited, it may be made of a material such as polyethylene terephthalate, polypropylene, crosslinked polyethylene, polyester, polybenzimidazole, polyimide, polyimideamide, polyetherimide, And can be formed by a resin. The thickness of the insulating film 203 is not particularly limited, but may be about 10 mu m to 30 mu m.

The printed circuit including the ground circuit 205 may be a copper wiring pattern formed on the base member 201, for example. On the surface of the ground circuit 205, a surface layer may be provided if necessary. The surface layer may be a plating layer made of, for example, gold, copper, nickel, silver, tin, or the like. In applications in which magnetism is a problem, it is preferable that the surface layer is made of a non-magnetic material.

The bonding of the wiring board reinforcing plate 100 to the wiring board 200 can be performed, for example, as follows. First, the reinforcing plate 100 for a wiring board is disposed on the wiring board 200 so that the conductive adhesive layer 102 is located above the opening. Then, the reinforcing plate 100 for a wiring board and the wiring board 200 are sandwiched from the top and bottom by two heating plates heated at a predetermined temperature (for example, 120 DEG C) , 0.5 MPa) for a short time (for example, 5 seconds). As a result, the reinforcing plate 100 for a wiring board is temporarily fixed to the wiring board 200.

Subsequently, the temperature of the two heating plates is set to a predetermined temperature (for example, 170 占 폚) higher than the fixed period of time and a predetermined time (for example, 30 Min). The reinforcing plate 100 for the wiring board is fixed to the wiring board 200 and the reinforcing wiring board 300 is formed with the conductive adhesive layer 102 filled in the opening.

Thereafter, a solder reflow process for component mounting is performed. In the reflow process, the wiring board 200 to which the reinforcing plate 100 for a wiring board is fixed is exposed to a high temperature of about 260 占 폚. The reflow process differs depending on the mounting form of the component, but is usually performed two to three times. The reinforcing plate 100 for a wiring board according to the present embodiment has a small change in connection resistance before and after the reflow process and can stably maintain a low connection resistance. The component to be mounted is not particularly limited, and examples thereof include a chip component such as a resistor and a capacitor in addition to a connector and an integrated circuit.

In the present embodiment, the conductive adhesive layer 102 is provided on one side of the gusset plate main body 101. However, as shown in Fig. 4, on both sides of the gusset plate main body 101, An adhesive layer 102 may be provided. In this case, Str may be set to 0.5 or more, preferably 0.6 or more, and more preferably 0.7 or more, on both sides of the reinforcing plate main body 101. By providing the conductive adhesive layer 102 on both sides, for example, one of the conductive adhesive layers 102 can be bonded to the wiring substrate, and the other conductive adhesive layer 102 can be bonded to the housing.

[Example]

Hereinafter, the reinforcing plate for a wiring board of the present disclosure will be described in more detail with reference to examples. The following examples are illustrative and are not intended to limit the invention.

≪ Formation of reinforcing plate for wiring board >

Followed by mixing and stirring using a star-type stirring / defoaming device to prepare a paste-like conductive adhesive composition. Thereafter, the conductive adhesive composition thus prepared was hand-coated on a polyethylene terephthalate film (separate film) subjected to releasing treatment using a plate-type applicator (doctor blade) and dried at 100 ° C for 3 minutes To prepare a conductive adhesive layer.

35 parts by mass of a polyurethane polyurea resin having an acid value of 2 mg KOH / g, 45 parts by mass of a polyurethane polyurea resin having an acid value of 26 mgKOH / g, 20 parts by mass of a phenoxy type epoxy resin (trade name: jER4275, manufactured by Mitsubishi Chemical Corporation) , 20 parts by mass of a phenol novolac epoxy resin (trade name: jER152, manufactured by Mitsubishi Chemical Corporation) and 5 parts by mass of a rubber-modified epoxy resin (trade name: ERP-4030 available from Asahi Denka Co., Ltd.) Used. As the block isocyanate curing agent, Duranate 17B-60PX (manufactured by Asahi Kasei Chemical Co., Ltd.) was used, and as the imidazole-based curing accelerator, 2MA-OK (manufactured by Shikoku Kasei Co., ) Were used. As the conductive filler, a dendritic silver-coated copper alloy (average particle diameter: 15 mu m) was used. The content of the conductive filler was set to 150 parts by mass with respect to 100 parts by mass of the binder resin.

Next, the obtained conductive adhesive layer was disposed on the surface of a predetermined metal plate and heated and pressed under the conditions of a temperature of 120 DEG C, a time of 5 seconds and a pressure of 0.5 MPa using a press machine to produce a reinforcing plate for a wiring board .

≪ Formation of reinforced wiring board >

After separating the separable film on the conductive adhesive film, the reinforcing plate for the wiring board was hot-pressed onto the wiring board under the conditions of a temperature of 120 DEG C, a time of 5 seconds, and a pressure of 0.5 MPa. Thereafter, a reinforced wiring board was prepared by adhering under the conditions of a temperature of 170 DEG C, a time of 3 minutes and a pressure of 2 to 3 MPa in a press machine.

1, a copper foil pattern 205 in which a ground circuit is similar is formed on a base member 201 made of a polyimide film, and an insulating adhesive layer 202 is formed thereon. And a coverlay (insulating film) 203 made of a polyimide film were formed on a flexible printed wiring board. On the surface of the copper foil pattern 205, a plating layer was provided as a surface layer. Then, an opening portion simulating a ground connection portion having a diameter of 0.5 mm was formed in the cover rail 203.

≪ Measurement of surface property &

Str and Sa on the surface of the metal plate were measured using a confocal microscope (OPTELICS HYBRID, manufactured by Lasertec), and then subjected to surface inclination correction using data analysis software (LMeye7) Str and Sa were obtained. The measurement was carried out at arbitrary three points on the surface of the insulating layer of the electromagnetic wave shielding film and the average thereof was determined.

≪ Measurement of connection resistance >

The electrical resistance value between the copper foil pattern 205 and the metal plate 101 was measured by an ohmmeter with respect to the prepared reinforcing wiring board to obtain an initial connection resistance (connection resistance before reflow).

Next, after the produced reinforcing wiring board was passed through the hot air reflow apparatus three times, the connection resistance after the reflow was measured by the above-described method. The conditions of the reflow were set by assuming a lead free solder (Pb free solder) so that the coverlay on the reinforced wiring board was exposed to 265 ° C for 5 seconds.

(Example 1)

As the metal plate, a surface roughened SUS 304 plate having a thickness of 0.2 mm was used. Str was 0.79 and Sa was 1.83 mu m.

The initial connection resistance before reflow was 0.08? / 1, and the connection resistance after three reflows was 0.21? / 1.

(Example 2)

As the metal plate, a surface roughing-treated SUS304 plate having a thickness of 0.3 mm was used. Str was 0.83, and Sa was 0.88 탆.

The initial connection resistance before reflow was 0.07? / 1, and the connection resistance after three reflows was 0.18? / 1.

(Example 3)

As the metal plate, a surface roughing-treated SUS304 plate having a thickness of 0.3 mm was used. Str was 0.78, and Sa was 0.41 mu m.

The initial connection resistance before reflow was 0.05 Ω / hole, and the connection resistance after three reflow was 0.08 Ω / hole.

(Example 4)

As the metal plate, a surface roughened SUS 304 plate having a thickness of 0.2 mm was used. Str was 0.70, and Sa was 0.96 mu m.

The initial connection resistance before reflow was 0.04? / 1, and the connection resistance after three reflows was 0.07? / 1.

(Example 5)

As the metal plate, a surface roughened SUS 304 plate having a thickness of 0.5 mm was used. Str was 0.82, and Sa was 0.12 占 퐉.

The initial connection resistance before reflow was 0.11? / 1, and the connection resistance after 3 reflows was 0.20? / 1.

(Example 6)

As the metal plate, a surface roughened SUS304 plate having a thickness of 0.4 mm was used. Str was 0.86, and Sa was 0.14 mu m.

The initial connection resistance before reflow was 0.10? / 1, and the connection resistance after three reflows was 0.14? / 1.

(Example 7)

As the metal plate, a surface roughing treatment SUS304 plate having a thickness of 0.2 mm was subjected to surface resistance reduction treatment by lithium ion. Str was 0.82, and Sa was 2.02 mu m.

The initial connection resistance before reflow was 0.06? / 1, and the connection resistance after three reflows was 0.06? / 1.

(Example 8)

As the metal plate, a SUS304 plate having a surface roughness of 0.1 mm was subjected to atmospheric annealing and rinsing with acid, and then subjected to surface resistance reduction treatment with lithium ions. Str was 0.72, and Sa was 1.33 占 퐉.

The initial connection resistance before reflow was 0.05 Ω / hole, and the connection resistance after three reflow was 0.08 Ω / hole.

(Example 9)

As the metal plate, a SUS304 plate having a surface roughness of 0.1 mm and subjected to a surface resistance reduction treatment by lithium ion was used. Str was 0.89, and Sa was 0.65 占 퐉.

The initial connection resistance before reflow was 0.06? / 1, and the connection resistance after three reflows was 0.13? / 1.

(Comparative Example 1)

As the metal plate, a surface roughing-treated SUS304 plate having a thickness of 0.3 mm was used. Str was 0.42, and Sa was 0.03 mu m.

The initial connection resistance before reflow was 0.23? / 1, and the connection resistance after reflow three times was 0.77? / 1.

(Comparative Example 2)

As the metal plate, a surface roughing-treated SUS304 plate having a thickness of 0.3 mm was used. Str was 0.48, and Sa was 0.14 mu m.

The initial connection resistance before reflow was 0.32? / 1, and the connection resistance after three reflows was 1.0? / 1.

For each of the examples and comparative examples, the characteristics and measured values are summarized in Table 1.

[Table 1]

The reinforcing plate for a wiring board of the present disclosure can suppress an increase in connection resistance after reflow and is useful as a reinforcing and shielding of a flexible printed wiring board or the like.

100: reinforcing plate for wiring board
101: metal plate
101A: first side
102: Conductive adhesive layer
105: Plating layer
200: wiring board
201: base member
202: adhesive layer
203: insulating film
205: Ground circuit
210: Resistance meter
300: reinforced wiring board

Claims (8)

The reinforcing plate main body and
And a first conductive adhesive layer provided on a first surface of the reinforcing plate body,
Wherein an aspect ratio of a surface property of the reinforcing plate main body on the first surface is 0.5 or more. The method according to claim 1,
Wherein the reinforcing plate main body has an arithmetic average height on the first surface of 0.10 탆 or more. 3. The method according to claim 1 or 2,
Wherein the reinforcing plate main body is made of austenitic stainless steel. 4. The method according to any one of claims 1 to 3,
Wherein the first conductive adhesive layer is in direct contact with the first surface of the reinforcing plate main body. 4. The method according to any one of claims 1 to 3,
And a plating layer provided between the first conductive adhesive layer and the reinforcing plate main body. 6. The method of claim 5,
Wherein the plating layer is a nickel-phosphorus plating layer. 7. The method according to any one of claims 1 to 6,
And a second conductive adhesive layer provided on a second surface of the reinforcing plate main body,
And the aspect ratio of the surface property of the reinforcing plate main body on the second surface is 0.5 or more. A wiring board having a ground circuit and
The reinforced wiring board according to any one of claims 1 to 7, which is bonded to the wiring board so that the ground circuit and the reinforcing plate body are electrically connected to each other.

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