JP2021193709A - Laminated body and manufacturing method thereof - Google Patents

Abstract

To provide a laminated body and a manufacturing method thereof excellent in the adhesiveness of a metal plate to wiring of a printed wiring board and the reinforcing property of the wiring board.SOLUTION: A laminated body according to an embodiment of the present disclosure includes a printed circuit board with a board and wiring placed on the surface of this board, a solder layer placed on the wiring, a first metal plate placed on the solder layer, and a second metal plate placed on the first metal plate, and the wiring and the first metal plate are bonded via the solder layer, the first metal plate and the second metal plate are welded, and welded portions of the first metal plate and the second metal plate have a wavy boundary in cross-sectional view in a direction perpendicular to the substrate.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a laminate and a method for producing the same.

Printed wiring boards are widely used to construct circuits for various electronic devices. In recent years, with the miniaturization of electronic devices, the miniaturization of printed wiring boards and the increase in the wiring density thereof have been remarkable. This printed wiring board has a substrate and wiring arranged on the surface of the substrate.

In order to reinforce such a printed wiring board, it has been proposed to bond a reinforcing metal plate to the wiring by using a conductive adhesive layer (see JP-A-2018-556542).

Japanese Unexamined Patent Publication No. 2018-56542

Adhesion with a conductive adhesive as described above cannot be said to have sufficient adhesive force (adhesiveness) and reinforcing force (reinforcing property) of the metal plate to the wiring.

Therefore, it is an object of the present invention to provide a laminate having excellent adhesiveness of a metal plate to wiring of a printed wiring board and reinforcing property of the wiring board, and a method for manufacturing the same.

The laminate according to one aspect of the present disclosure made to solve the above problems includes a substrate, a printed wiring board having a wiring arranged on the surface of the substrate, a solder layer arranged on the wiring, and the above. A first metal plate arranged on the solder layer and a second metal plate arranged on the first metal plate are provided, and the wiring and the first metal plate are bonded via the solder layer. The first metal plate and the second metal plate are welded, and the welded portions of the first metal plate and the second metal plate have a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate.

A method for manufacturing a laminate according to another aspect of the present disclosure, which has been made to solve the above problems, is a printed wiring board having a substrate and wiring arranged on the surface of the substrate, and solder arranged on the wiring. A layer, a first metal plate arranged on the solder layer, and a second metal plate arranged on the first metal plate are provided, and the wiring and the first metal plate are interposed via the solder layer. The first metal plate and the second metal plate are welded together, and the welded portion of the first metal plate and the second metal plate is a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate. The first laminating step of laminating the solder paste on the wiring of the wiring plate, and after the first laminating step, the first metal plate is laminated on the solder paste. A second laminating step, a reflow step of reflowing the solder paste after the second laminating step, a third laminating step of laminating the second metal plate on the first metal plate after the reflowing step, and the above. After the third laminating step, the first metal plate and the second metal plate are provided with a laser welding step of laser welding by irradiating the first metal plate and the second metal plate while scanning the laser beam.

The laminate according to one aspect of the present disclosure is excellent in the adhesiveness of the metal plate to the wiring of the printed wiring board and the reinforcing property of the wiring board. The method for manufacturing a laminated body according to another aspect of the present disclosure can manufacture a laminated body having excellent adhesiveness of a metal plate to wiring of a printed wiring board and reinforcing property of the wiring board.

FIG. 1 is a schematic plan view showing the laminated body of the first embodiment. FIG. 2 is a schematic end view of the laminated body of FIG. 1 in the direction of arrow AA. FIG. 3 is a schematic end view for explaining a method for manufacturing the laminated body of FIG. 1, and is a schematic end view viewed in the same direction as the AA arrow viewing direction of FIG. FIG. 4 is a schematic end view for explaining the method for manufacturing the laminated body of FIG. 1, and is a schematic end view viewed in the same direction as the AA arrow viewing direction of FIG. FIG. 5 is a schematic end view for explaining the method of manufacturing the laminated body of FIG. 1, and is a schematic end view viewed in the same direction as the direction of arrow AA in FIG. FIG. 6 is a schematic end view for explaining the method of manufacturing the laminated body of FIG. 1, and is a schematic end view viewed in the same direction as the AA arrow viewing direction of FIG. FIG. 7 is a schematic plan view for explaining a method for manufacturing the laminate of FIG. 1. FIG. 8 is a schematic plan view showing the laminated body of the second embodiment. FIG. 9 is a schematic end view of FIG. 8 in the direction of the arrow BB.

[Explanation of Embodiments of the present disclosure]
The laminate according to one aspect of the present disclosure includes a printed wiring board having a substrate and wiring arranged on the surface of the substrate, a solder layer arranged on the wiring, and a first solder layer arranged on the solder layer. A metal plate and a second metal plate arranged on the first metal plate are provided, and the wiring and the first metal plate are bonded to each other via the solder layer, and the first metal plate and the first metal plate are bonded to each other. 2 The metal plate is welded, and the welded portion of the first metal plate and the second metal plate has a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate.

Here, as a result of diligent research by the present inventors, the following findings were obtained. That is, as shown in the above-mentioned patent document, when an attempt was made to bond the metal plate to the wiring of the printed wiring plate with a conductive adhesive, it was found that the adhesive strength between the wiring and the metal plate was insufficient. Moreover, it was found that the reinforcing property was insufficient.

On the other hand, when a metal plate was adhered to the above wiring via a solder layer, it was found that the reinforcing property was insufficient.

On the other hand, when an attempt was made to weld a metal plate to the wiring by laser welding, it was found that the wiring was damaged due to heating by laser irradiation.

Based on the above findings, the present inventors conducted further diligent research and obtained the following findings. That is, first, a first metal plate is adhered to the wiring via a solder layer, and a second metal plate is further laminated on the first metal plate. Next, when the first metal plate and the second metal plate were laser-welded while preventing the energy of the laser beam from being transmitted to the solder layer as much as possible, the first metal plate and the second metal plate were suppressed while suppressing damage to the wiring. Was found to be capable of welding with sufficient adhesive strength. It was also found to be excellent in reinforcing properties.

In addition, when the cross section of the welded portion perpendicular to the substrate was observed, it was found that the welded portion had a waveform boundary caused by irradiation with laser light, and the present invention was completed.

In this way, in the laminated body, the wiring and the first metal plate are adhered by the solder layer, and the first metal plate and the second metal plate have the above-mentioned cross section of the welded portion having the above-mentioned waveform. By being welded so as to have a boundary, the adhesiveness of the metal plate to the wiring and the reinforcing property of the wiring plate are excellent.

It is preferable that the first metal plate is made of stainless steel and the second metal plate is made of stainless steel.

As described above, since the first metal plate and the second metal plate are made of stainless steel, the wiring can be more sufficiently reinforced.

It is preferable that the welded portion and the solder layer are arranged so as to be spaced apart from each other when viewed in a direction perpendicular to the substrate.

In this way, the welded portion and the solder layer are arranged at intervals from each other when viewed in a direction perpendicular to the substrate, so that one of the solder layers is caused by heating when forming the welded portion. It is possible to prevent the portion from protruding to the outside of the first and second metal plates. Therefore, it is possible to suppress a decrease in the adhesive force between the wiring and the first metal plate due to the protrusion of the solder layer forming material. Therefore, the adhesive strength of the laminated body can be improved more reliably.

A method for manufacturing a laminate according to another aspect of the present disclosure is a printed wiring board having a substrate and wiring arranged on the surface of the substrate, a solder layer arranged on the wiring, and arrangement on the solder layer. A first metal plate to be formed and a second metal plate arranged on the first metal plate are provided, and the wiring and the first metal plate are bonded to each other via the solder layer, and the first metal is formed. A method for manufacturing a laminate in which a plate and the second metal plate are welded, and the welded portions of the first metal plate and the second metal plate have a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate. The first laminating step of laminating the solder paste on the wiring of the wiring plate, the second laminating step of laminating the first metal plate on the solder paste after the first laminating step, and the second laminating step. After the laminating step, a reflow step of reflowing the solder paste, a third laminating step of laminating the second metal plate on the first metal plate after the reflow step, and a first laminating step after the third laminating step. It is provided with a laser welding step of laser welding the metal plate and the second metal plate by irradiating the metal plate while scanning the laser beam.

According to this method for manufacturing the laminated body, the above-mentioned laminated body can be manufactured. That is, it is possible to manufacture a laminated body having excellent adhesiveness of the metal plate to the wiring of the printed wiring board and reinforcing property of the wiring board.

Here, the "boundary of the welded portion between the first metal plate and the second metal plate" means that the first metal plate and the second metal plate are welded to each other so that the welded portion is once. It is a boundary caused by discoloration due to deterioration due to solidification after melting, and is formed between the welded portion and a portion other than the welded portion in the first metal plate and the second metal plate. It is the boundary of macroscopic observation. The "waveform boundary" means that the cross-sectional shape of the boundary between the welded portion discolored as described above and the portion other than the welded portion is a wave shape.

[Details of Embodiments of the present disclosure]
Hereinafter, embodiments of the laminate and its manufacturing method according to the present disclosure will be described in detail with reference to the drawings. In the present embodiment, the "surface" refers to the surface on the side where the wiring is arranged in the thickness direction of the base film, and the front and back of the present embodiment refer to the front and back of the printed wiring board in the used state. It is not a decision.

[First Embodiment]
[Laminate]
As shown in FIGS. 1 and 2, the laminate 1 of the present embodiment has a printed wiring board 10 having a wiring board 11 arranged on the substrate 3 and the surface of the substrate 3, and solder arranged on the wiring 11. It includes a layer 20, a first metal plate 30 arranged on the solder layer 20, and a second metal plate 40 arranged on the first metal plate 30. The wiring 11 and the first metal plate 30 are adhered to each other via the solder layer 20. The first metal plate 30 and the second metal plate 40 are welded, and the welded portion 50 of the first metal plate 30 and the second metal plate 40 has a wavy shape in a cross-sectional view in a direction perpendicular to the substrate 3. Has boundaries.

<Printed wiring board>
The printed wiring board 10 has a base film 3 having an insulating property as a substrate, and a wiring 11 arranged on the surface of the base film 3.

(Base film)
The base film 3 is a layer made of a synthetic resin having an insulating property. The base film 3 is a base material for forming the wiring 11. The base film 3 may have flexibility. The material for forming the base film 3 is not particularly limited as long as it has an insulating property, and for example, a synthetic resin film having a low dielectric constant formed in a sheet shape can be adopted. Examples of the main component of this synthetic resin film include polyimide, polyethylene terephthalate, liquid crystal polymer, fluororesin and the like. The "main component" is a component having the highest content, and means, for example, a component that occupies 50% by mass or more in the forming material. The base film 3 may contain a resin other than the exemplified resin such as polyimide, an antistatic agent, and the like.

The lower limit of the average thickness of the base film 3 is not particularly limited, but is preferably 3 μm, preferably 5 μm, and more preferably 10 μm. The upper limit of the average thickness of the base film 3 is not particularly limited, but is preferably 200 μm, more preferably 150 μm, and even more preferably 100 μm. If the average thickness of the base film 3 is less than the above lower limit, the dielectric strength and mechanical strength of the base film 3 may be insufficient. On the other hand, when the average thickness of the base film 3 exceeds the above upper limit, the printed wiring board 1 may become unnecessarily thick. Here, the "average thickness" of the base film 3 means the average value of the thickness measured at any ten points.

(wiring)
The wiring 11 is arranged directly on the surface of the base film 3 or via another layer. Examples of the wiring 11 include a signal line for transmitting a signal, a current line for transmitting a current for supplying electric power, a current line for transmitting a current for generating a magnetic field, and the like.

The wiring 11 is formed by, for example, a conductive base layer arranged on the surface of the base film 3 and a plating layer arranged on the conductive base layer.

Examples of the material for forming the conductive base layer include copper (Cu), silver (Ag), gold (Au), nickel (Ni), titanium (Ti), chromium (Cr), alloys thereof, stainless steel and the like. Can be mentioned.

Examples of the metal material for forming the plating layer include copper, aluminum, silver, gold, nickel, and alloys thereof. Among these, copper or a copper alloy is preferable from the viewpoint of improving the conductivity and reducing the cost.

The average thickness of the conductive base layer and the plating layer can be appropriately set so that, for example, the average thickness of the wiring 11 is in the range described later.

As the lower limit of the average thickness of the wiring 11, for example, 10 μm is preferable, 15 μm is more preferable, 25 μm is further preferable, and 30 μm is particularly preferable. As the upper limit of the average thickness of the wiring 11, for example, 95 μm is preferable, 85 μm is more preferable, 75 μm is further preferable, and 70 μm is particularly preferable. If the average thickness of the wiring 11 is less than the above lower limit, the resistance of the wiring 11 may become excessive as the wiring density increases. On the other hand, if the average thickness of the wiring 11 exceeds the above upper limit, the printed wiring board 10 may become unnecessarily thick. The "average thickness" of the wiring 11 is a value obtained by averaging the maximum height of the wiring 11 in the cross section perpendicular to the longitudinal direction of the wiring 11 in the longitudinal direction of the wiring 11.

As the lower limit of the average line width of the wiring 11, for example, 10 μm is preferable, 15 μm is more preferable, 25 μm is further preferable, and 30 μm is particularly preferable. As the upper limit of the average line width of the wiring 11, for example, 95 μm is preferable, 85 μm is more preferable, 75 μm is further preferable, and 70 μm is particularly preferable. If the average line width of the wiring 11 is less than the above lower limit, it may be difficult to form the wiring 11. On the other hand, if the average line width of the wiring 11 exceeds the above upper limit, the wiring density may not meet the requirement. Here, the "average line width" of the wiring 11 is a value obtained by averaging the maximum width in the cross section perpendicular to the longitudinal direction of the wiring 11 in the longitudinal direction of the wiring 11.

When the printed wiring board 10 has a plurality of wirings 11, the solder layer 20, the first metal plate 30, and the second metal plate 40 are laminated on at least one of the wirings 11. As the upper limit of the average spacing of the wirings 11 adjacent to each other, for example, 10 μm is preferable, 15 μm is more preferable, 25 μm is further preferable, and 30 μm is particularly preferable. As the upper limit of the average spacing of the wiring 11, for example, 95 μm is preferable, 85 μm is more preferable, 75 μm is further preferable, and 70 μm is particularly preferable. If the average spacing of the wirings 11 is less than the lower limit, there is a risk of short-circuiting between the wirings 11 adjacent to each other. On the other hand, if the average spacing of the wiring 11 exceeds the upper limit, the wiring density may not meet the requirement. Here, the "average spacing" of the wiring 11 is a value obtained by averaging the minimum distance between the opposite side edges of the adjacent wiring 11 in the cross section perpendicular to the longitudinal direction of the wiring 11 in the longitudinal direction of the wiring 11.

(Manufacturing method of printed wiring board)
The printed wiring board 10 can be manufactured by a known method such as a subtractive method or a semi-additive method. For example, in the subtractive method, a conductive base layer is formed on the base film 3, a plating layer is formed on the conductive base layer, a resist pattern is formed on the plating layer, and the resist pattern is used as a mask as described above. A printed wiring board can be manufactured by removing the resist pattern after etching the plating layer and the conductive base layer.

On the other hand, for example, in the semi-additive method, a conductive base layer is formed on the base film 3, a resist pattern is formed on the conductive base layer, a plating layer is formed at an opening of the resist pattern, and a resist pattern is formed. After removal, a printed wiring board can be manufactured by etching the non-laminated region of the plating layer in the conductive base layer with the plating layer as a mask.

(Solder layer)
The solder layer 20 is arranged between the wiring 11 and the first metal plate 30, and adheres the wiring 11 and the first metal plate 30. The solder layer 20 contains, for example, tin, copper, or an alloy thereof. The solder layer 20 is formed by laminating a solder paste containing the metal on the wiring 11, laminating the first metal plate 20 on the solder paste, and then performing reflow.

The lower limit of the average thickness of the solder layer 20 is preferably 20 μm, more preferably 25 μm. The upper limit of the average thickness of the solder layer 20 is preferably 40 μm, more preferably 35 μm. If the average thickness of the solder layer 20 does not reach the above lower limit, the adhesive force between the wiring 11 and the first metal plate 30 may be insufficient. On the other hand, if the average thickness of the solder layer 20 exceeds the above upper limit, when the first metal plate 30 and the second metal plate 40 are welded, the solder layer 20 may be melted by heating and may protrude to the outside.

The length in the longitudinal direction (extending direction of the wiring 11) and the length in the width direction (direction perpendicular to the extending direction of the wiring 11) of the solder layer 20 are between the wiring 11 and the first metal plate 30. It can be appropriately set according to the adhesive strength and the like.

(1st metal plate)
The first metal plate 30 is arranged on the solder layer 20 and is adhered to the wiring 11 via the solder layer 20. In addition, the first metal plate 30 is welded to the second metal plate 40. Such a first metal plate 30 constitutes a base for fixing the second metal plate 40 to the wiring 11.

Examples of the material for forming the first metal plate 30 include stainless steel. Examples of the stainless steel include SUS304 and the like. Since the first metal plate 30 is made of stainless steel, the wiring 11 can be reinforced more sufficiently.

The lower limit of the average thickness of the first metal plate 30 is preferably 10 μm, more preferably 20 μm, and even more preferably 50 μm. The upper limit of the average thickness of the first metal plate 30 is preferably 1000 μm, more preferably 500 μm, and even more preferably 200 μm. If the average thickness of the first metal plate 30 does not meet the above lower limit, the first metal plate 30 may be too light to sufficiently hold the second metal plate 40. On the other hand, if the average thickness of the first metal plate 30 exceeds the above upper limit, the first metal plate 30 may be too heavy for the solder layer 20 to sufficiently hold the first metal plate 30.

The length in the longitudinal direction (extending direction of the wiring 11) and the length in the width direction (direction perpendicular to the extending direction of the wiring 11) of the first metal plate 30 are the lengths of the wiring 11 and the first metal plate 30. It can be appropriately set according to the adhesive force of the solder layer 20 between them, the adhesive force between the first metal plate 30 and the second metal plate 40, and the like.

(2nd metal plate)
The second metal plate 40 is arranged on the first metal plate 30 and is fixed to the wiring 11 via the solder layer 20 and the first metal plate 30. The second metal plate 40 is welded to the first metal plate 30. Such a second metal plate 40 constitutes a reinforcing plate for reinforcing the wiring 11.

Examples of the material for forming the second metal plate 40 include stainless steel. Examples of the stainless steel include SUS304 and the like. Since the second metal plate 40 is made of stainless steel, the wiring 11 can be reinforced more sufficiently. As the forming material of the second metal plate 40, the same kind of forming material as that of the first metal plate 30 is preferable. Since the forming material of the second metal plate 40 is the same as the forming material of the first metal plate 30, the first metal plate 30 and the second metal plate 40 can be easily welded.

The lower limit of the average thickness of the second metal plate 40 is preferably 10 μm, more preferably 20 μm, and even more preferably 50 μm. The upper limit of the average thickness of the second metal plate 40 is preferably 1000 μm, more preferably 500 μm, and even more preferably 200 μm. If the average thickness of the second metal plate 40 does not reach the above lower limit, the second metal plate 40 may be too light to sufficiently fulfill its role as a reinforcing plate. On the other hand, when the average thickness of the second metal plate 40 exceeds the above upper limit, the second metal plate 40 is too heavy, and the first metal plate 30 (and indirectly the solder layer 20) uses the second metal plate 40. It may not be possible to hold it sufficiently.

The length of the second metal plate 40 in the longitudinal direction (extending direction of the wiring 11) and the length in the width direction (direction perpendicular to the extending direction of the wiring 11) are the first metal plate 30 and the second metal plate. It can be appropriately set according to the adhesive force between the 40 and the solder layer 20 between the first metal plate 30 to which the second metal plate 40 is welded and the wiring 11.

(Welding of the first metal plate and the second metal plate)
The first metal plate 30 and the second metal plate 40 are welded together, and the welded portion 50 of the first metal plate 30 and the second metal plate 40 has a cross section in a direction perpendicular to the base film 3 as shown in FIG. It has a wavy boundary 51 visually. Such a wave-shaped welded portion 50 is formed by laminating a second metal plate 40 on a first metal plate 30 and irradiating the upper surface of the second metal plate 40 while scanning a laser beam. Specifically, as will be described later, the boundary between the laser irradiation mark (hereinafter, also referred to as “laser mark”) and the portion not irradiated with the laser is formed in the above wave shape. In the present embodiment, the welded portion 50 is formed in a shape smaller than the solder layer 20 (, the wiring 11, the first metal plate 30 and the second metal plate 40) in a plan view.

[Manufacturing method of laminated body]
Next, a method for manufacturing the laminated body of the present embodiment will be described.

In the laminated body of the present embodiment, the first metal plate 30 is placed on the solder paste 21 after the first laminating step of laminating the solder paste 21 on the wiring 11 of the printed wiring board 10 and the first laminating step. A third laminating step of laminating the second metal plate 40 on the first metal plate 30 after the second laminating step, the reflow step of reflowing the solder paste 21 after the second laminating step, and the reflow step. A laminating step and a laser welding step of laser welding the first metal plate 30 and the second metal plate 40 by irradiating the first metal plate 30 and the second metal plate 40 while scanning the laser beam after the third laminating step are provided.

(First laminating process)
In this step, as shown in FIG. 3, the solder paste 21 is laminated on the wiring 11 of the printed wiring board 10.

(Second laminating process)
In this step, as shown in FIGS. 3 and 4, after the first laminating step, the first metal plate 30 is laminated on the solder paste 21.

(Reflow process)
In this step, the solder paste 21 is reflowed after the second laminating step. By this reflow, as shown in FIG. 4, a solder layer 20 is formed between the wiring 11 and the first metal plate 30. The first metal plate 30 is adhered to the wiring 11 by the solder layer 20.

(Third laminating process)
In this step, as shown in FIG. 5, after the reflow step, the second metal plate 40 is laminated on the first metal plate 30.

(Welding process)
In this step, as shown in FIGS. 6 and 7, after the third laminating step, the first metal plate 30 and the second metal plate 40 are laser-welded by irradiating the first metal plate 30 and the second metal plate 40 while scanning the laser beam R. For example, as shown in FIGS. 6 and 7, a laser beam R is irradiated to a predetermined position from above the second metal plate 40 toward the second metal plate 40, centered on the predetermined position, and the center thereof. The laser beam R is emitted so as to draw a spiral from the outside.

As shown in FIG. 6, when the laser beam R is irradiated to the center, the energy of the laser beam R reaches the inside of the first metal plate 30 via the second metal plate 40. At this time, if the energy of the laser beam R does not reach the inside of the first metal plate 30, or if the depth reached by the laser beam R even if it reaches the inside is too small, the first metal plate 30 and the second metal plate 30 and the second. It becomes difficult to sufficiently weld the metal plate 40. On the other hand, if the reach depth of the energy of the laser beam R is too large, the solder layer 20 may be melted due to this energy. Therefore, in consideration of these, the depth at which the energy of the laser beam R reaches inside the first metal plate 30 is such that the adhesive force between the first metal plate 30 and the second metal plate 40 is sufficient and the solder layer is formed. It can be appropriately set to the extent that melting of 20 does not occur.

When the reachable depth of the energy of the laser beam R is set to a desired depth and the laser beam R is irradiated to a predetermined position on the second metal plate 40 in this way, as shown in FIG. 6, the first The region affected by the energy in the metal plate 30 and the second metal plate 40 is once melted and then solidified again to become a welded portion 50 (see FIG. 2). After being melted once in this way, the welded portion 50 is discolored due to solidification. Due to the discoloration of the welded portion 50, the boundary 51 is visually observed between the welded portion 50 and the other portions. The boundary 51 is a boundary between a region affected by the laser beam R and a region not affected by the laser beam R. The boundary 51 has a curved shape so as to project from the fourth metal plate 40 toward the first metal plate 30.

Next, when the laser light R is scanned so as to draw a spiral outward with the predetermined position as the center, the region affected by the energy of the laser light R increases accordingly, and the boundary 51 is bent. It becomes a wave shape in which the formed shapes are continuously connected.

The scanning path (moving locus) of the laser beam R can be appropriately set so that the welded portion 50 having the wave-shaped boundary as described above is formed. As shown in FIG. 7, such a scanning path includes, for example, a path in which the laser beam R is scanned so as to draw a spiral from the center to a predetermined position in a plan view. Examples of the traveling path include a path in which a predetermined position is set as an outer end in a plan view and the laser beam R is scanned so as to draw a spiral inward from the outer end. As the traveling route, for example, after scanning in an arbitrary first direction starting from a predetermined position, the first direction is adjacent to the scanning in the second direction perpendicular to the first direction. A method of scanning in the opposite direction and repeating these scans can be mentioned.

Examples of the laser beam R include a YAG laser having a wavelength of 1064 nm. Examples of the YAG laser include a YAG pulse laser. Examples of the laser device capable of emitting such a laser beam R include a conventionally known laser device. For example, when the laser light R is the YAG pulse laser, the laser conditions can be set as follows.
First metal plate 30: Stainless steel (SUS304) plate with an average thickness of 100 μm Second metal plate 40: Stainless steel (SUS304) plate with an average thickness of 100 μm Laser light output: 20 to 30 W
Laser light spot diameter (D): 40 to 50 μm,
Laser light scanning speed: 140-160 mm / sec
Laser light pulse frequency: 700-900KHz,
Laser light pulse width: 5-10 μm
Spiral outer diameter: 0.6 mm to 0.8 mm
Spiral pitch: 0.05 to 0.15 mm
Laser height (distance between the light source and the second metal plate 40): 160-170 mm

The laminated body 1 can be manufactured by welding the first metal plate 30 and the second metal plate 40 while scanning the laser beam R as described above.

<Advantage>
In the laminated body 1, the wiring 11 and the first metal plate 30 are bonded by the solder layer 20, and the first metal plate 30 and the second metal plate 40 have a corrugated boundary as described above in the cross section of the welded portion 50. By being welded so as to have the above, the adhesiveness of the first metal plate 30 and the second metal plate 40 to the wiring 11 and the reinforcing property of the printed wiring plate 10 are excellent. According to the method for manufacturing the laminated body, the laminated body 1 can be manufactured. That is, it is possible to manufacture the laminated body 1 having excellent adhesiveness between the first metal plate 30 and the second metal plate 40 to the wiring 11 of the printed wiring board 10 and the reinforcing property of the wiring board 10.

[Second Embodiment]
As shown in FIGS. 8 and 9, the laminated body 1a of the present embodiment includes a plurality of (here, 2) solder layers 20 on the wiring 11, and the welded portion 50 and the plurality of solder layers 20 are base films. They are arranged so as to be spaced apart from each other when viewed in a direction perpendicular to 3 (viewed in a direction perpendicular to the paper surface of FIG. 9, that is, in a plan view). Since the other configurations are exactly the same as those of the first embodiment, only the configurations different from those of the first embodiment will be described, and the other configurations of the laminated body 1a will be described with the same reference numerals as those of the first embodiment. Omit.

In the present embodiment, the solder layer 20 of 2 is formed in a shape smaller than that of the first metal layer 30 (, the wiring 11, the second metal plate 40) in a plan view, respectively. These two solder layers 20 are arranged at intervals from each other in a plan view. The solder layer 20 of 2 is arranged at a position sandwiching the welded portion 50 in a plan view with a gap from the welded portion 50, respectively. In addition, the solder layer 20 of the above 2 is arranged at a position spaced apart from each end edge of the wiring 11 and the first metal plate 30, respectively. In a plan view, the dimensions of each solder layer 20 are the distance between each solder layer 20 and the welded portion 50 as described above, the distance between each solder layer 20 and the wiring 11, and the distance from each end edge of the first metal plate 30 and the like. It can be set as appropriate according to the situation.

In this way, in a plan view, the solder layers 20 of the welded portion 50 and 2 are arranged at intervals from each other, so that a part of each solder layer 20 is caused by heating when the welded portion 50 is formed. Can be prevented from protruding to the outside of the wiring 11 and the first metal plate 30. Therefore, it is possible to suppress a decrease in the adhesive force between the wiring 11 and the first metal plate 30 due to the protrusion of each solder layer 20. Therefore, the adhesive strength of the laminated body 1a can be improved more reliably.

The distance between each solder layer 20 and the welded portion 50 in a plan view can be appropriately set so that a part of each solder layer 20 does not protrude from between the wiring 11 and the first metal plate 30. The distance between each solder layer 20 and each end edge of the wiring 11 and the first metal plate 30 in a plan view is also such that a part of each solder layer 20 does not protrude from the wiring 11 and the first metal plate 30. Can be set as appropriate.

<Advantage>
Similar to the first embodiment, the laminated body 1a is excellent in the adhesiveness of the first metal plate 30 and the second metal plate 40 to the wiring 11 of the printed wiring board 10 and the reinforcing property of the wiring board 10. In addition, in the present embodiment, as described above, the plurality of solder layers 20 and the welded portions 50 are arranged at intervals from each other in a plan view, so that the adhesive strength of the laminated body 1a is further increased as described above. It can be definitely improved.

[Other embodiments]
It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is not limited to the configuration of the above embodiment, but is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. To.

In each of the above embodiments, the case where the laminate includes a single base film and a printed wiring board having wiring arranged on one surface of the base film has been described, but the laminate is a single. It may be provided with a printed wiring board having wiring on both surfaces of the base film. In this case, the solder layer, the first metal plate, and the second metal plate may be laminated on each wiring on both surfaces of the base film, respectively.

In the second embodiment, the case where the laminated body includes two solder layers has been described, but the number of solder layers may be 1 or more, and is not particularly limited, for example, the wiring 11 and the first metal plate 30. It can be appropriately set according to the adhesive force between the solders.

The laminate according to the embodiment of the present disclosure is excellent in the adhesiveness of the metal plate to the wiring of the printed wiring board and the reinforcing property of the wiring board, so that it can be suitably used for a small electronic device or the like.

1, 1a Laminated plate 10 Printed wiring plate 3 Base film 11 Wiring 20 Solder layer 21 Solder paste 30 First metal plate 40 Second metal plate 50 Welded part 51 Boundary R Laser light

Claims (4)

A printed circuit board with a board and wiring placed on the surface of this board,
The solder layer placed on the above wiring and
The first metal plate arranged on the solder layer and
With a second metal plate arranged on the first metal plate,
The wiring and the first metal plate are adhered to each other via the solder layer.
The first metal plate and the second metal plate are welded together.
A laminate in which the welded portion of the first metal plate and the second metal plate has a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate. The first metal plate is made of stainless steel.
The laminate according to claim 1, wherein the second metal plate is made of stainless steel. The laminate according to claim 1 or 2, wherein the welded portion and the solder layer are arranged at intervals from each other when viewed in a direction perpendicular to the substrate. A printed circuit board with a board and wiring placed on the surface of this board,
The solder layer placed on the above wiring and
The first metal plate arranged on the solder layer and
With a second metal plate arranged on the first metal plate,
The wiring and the first metal plate are adhered to each other via the solder layer.
The first metal plate and the second metal plate are welded together.
A method for manufacturing a laminate in which the welded portion of the first metal plate and the second metal plate has a wavy boundary in a cross-sectional view in a direction perpendicular to the substrate.
The first laminating step of laminating the solder paste on the wiring of the wiring board, and
After the first laminating step, a second laminating step of laminating the first metal plate on the solder paste, and a second laminating step.
After the second laminating step, a reflow step of reflowing the solder paste and a reflow step of reflowing the solder paste,
After the reflow step, a third laminating step of laminating the second metal plate on the first metal plate, and a third laminating step.
A method for manufacturing a laminated body, comprising a laser welding step of irradiating the first metal plate and the second metal plate with a laser beam while scanning the laser beam after the third laminating step.

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