CN111836474A - Electronic device and its manufacturing method, and printed circuit board and its manufacturing method - Google Patents

Abstract

The invention provides an electronic device and a manufacturing method thereof, and a printed circuit board and a manufacturing method thereof, which can improve environmental resistance. An electronic device (1) is provided with a printed circuit board (5), wherein the printed circuit board (5) is provided with a substrate (9); a copper layer (12) formed on the substrate (9); a flash plating layer (29) formed so as to cover the pad portions (13, 15) of the through-hole (11) in the copper layer (12) and the inner wall portion (17) of the through-hole (11); and a solder plating layer (39) formed so as to cover the flash plating layer (29).

Description

Electronic device and its manufacturing method, and printed circuit board and its manufacturing method

technical field

The disclosed embodiments relate to an electronic device, a method of manufacturing the electronic device, a printed circuit board, and a method of manufacturing the printed circuit board.

Background technique

Patent Document 1 describes a method for producing a printed wiring board subjected to flash plating.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2009-152483.

SUMMARY OF THE INVENTION

The problem to be solved by the invention

For example, in a substrate subjected to flash plating, favorable environmental resistance may not be obtained in an environment of corrosive gas, and improvement in environmental resistance is required.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an electronic device capable of improving environmental resistance, a method for manufacturing the electronic device, a printed circuit board, and a method for manufacturing a printed circuit board.

method used to solve the problem

In order to solve the above-mentioned problems, according to an aspect of the present invention, an electronic device is applied, which includes a printed circuit board including: a substrate; a copper layer formed on the substrate; and a flash plating layer formed to cover the copper layer and a solder plating layer formed to cover the flash plating layer.

In addition, according to another aspect of the present invention, there is applied a method of manufacturing an electronic device including a printed circuit board, the manufacturing method having the steps of: mounting a component on the substrate and covering the substrate with a predetermined copper layer. A flash plating layer is formed on the part; and the step of assembling the board on which the component is mounted is incorporated into a frame, and the step of mounting the component to the substrate includes a step of forming a solder plating layer so as to cover the flash plating layer.

In addition, according to another aspect of the present invention, a printed circuit board including: a substrate; a copper layer formed on the substrate; and a flash plating layer formed so as to cover the copper layer is applied and mounted on an electronic device. a predetermined portion; and a solder plating layer formed to cover the flash plating layer.

In addition, according to another aspect of the present invention, there is applied a method for manufacturing a printed circuit board mounted on an electronic device, the manufacturing method having a step of mounting a component on a substrate, and applying a copper layer-covered substrate on the substrate. A flash plating layer is formed at a predetermined position, and the step of mounting the component on the substrate includes a step of forming a solder plating layer so as to cover the flash plating layer.

Invention effect

According to the electronic device and the like of the present invention, the environmental resistance can be improved.

Description of drawings

FIG. 1 is a perspective view showing an example of a schematic configuration of an electronic device according to the present embodiment;

FIG. 2 is a flowchart showing an example of a method of manufacturing the electronic device according to the present embodiment;

3 is a cross-sectional view illustrating a cross-sectional structure of a through hole portion of a printed wiring board;

4 is a flowchart showing an example of a detailed process of SMD mounting (first surface) performed in step S2 of FIG. 2;

FIG. 5 is a cross-sectional view corresponding to step S21 in FIG. 4 , showing a cross-sectional structure of a through hole portion of the printed wiring board extracted;

FIG. 6 is a cross-sectional view corresponding to step S22 of FIG. 4 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

FIG. 7 is a cross-sectional view corresponding to step S23 of FIG. 4 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

8 is a flowchart showing an example of a detailed process of SMD mounting (second surface) performed in step S3 of FIG. 2;

FIG. 9 is a cross-sectional view corresponding to step S31 of FIG. 8 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

FIG. 10 is a cross-sectional view corresponding to step S32 of FIG. 8 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

FIG. 11 is a cross-sectional view corresponding to step S33 in FIG. 8 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

12 is a flowchart showing an example of a detailed process of DIP mounting (second surface) performed in step S4 of FIG. 2;

FIG. 13 is a cross-sectional view corresponding to step S41 in FIG. 12 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

FIG. 14 is a cross-sectional view corresponding to step S42 in FIG. 12 , showing the cross-sectional structure of the through hole portion of the printed wiring board extracted;

15 is a flowchart showing an example of a detailed process of DIP mounting (first surface) performed in step S5 of FIG. 2;

16 is a cross-sectional view showing an example of a structural member mounted on a printed circuit board in step S6 of FIG. 2 , showing a cross-sectional structure of a through-hole portion of the printed circuit board;

17 is a cross-sectional view showing a cross-sectional structure of a through-hole portion of a printed wiring board, corresponding to step S41 in FIG. 12 , in a modification in which printing of solder paste is performed only on the pad portion on one side;

18 is a cross-sectional view showing a cross-sectional structure of a through-hole portion of a printed wiring board, corresponding to step S42 in FIG. 12 , in the modification example in which the solder paste is printed only on the pad portion on one side.

Detailed ways

Hereinafter, one embodiment will be described with reference to the drawings.

<1. Schematic structure of electronic equipment>

First, an example of a schematic configuration of an electronic device according to the present embodiment will be described with reference to FIG. 1 .

As shown in FIG. 1 , the electronic device 1 includes a housing 3 and a plurality of (for example, five) printed circuit boards 5 . The respective printed circuit boards 5 are erected in a direction perpendicular to the bottom plate 3 a of the housing 3 via a connector not shown, and are arranged in parallel to each other. In addition, the number of the printed circuit boards 5 mounted on the electronic device 1 is not limited to plural, and may be single. In addition, the printed circuit board 5 may be provided in parallel with respect to the base plate 3a.

The electronic device 1 is, for example, a motor control device that controls a motor. However, the application target of the electronic device 1 is not particularly limited as long as it is a device including a printed circuit board. For example, it can be applied to a control device that controls a drive machine other than a motor, various industrial equipment, or a computer, a smartphone, or the like.

In addition, the “printed board” in the present embodiment is not a so-called printed wiring board (PWB: Printed Wiring Board) before mounting electronic components, but refers to a so-called printed wiring board (PCB: Printed Wiring Board) on which electronic components are mounted and operates as an electronic circuit Circuit Board).

<2. Manufacturing process of electronic equipment>

Next, an example of a manufacturing process (manufacturing method) of the electronic device according to the present embodiment will be described with reference to FIG. 2 .

In step S1, a printed wiring board (PWB) and electronic components and the like mounted on the printed wiring board are prepared. Although the details will be described later, a copper layer such as pattern wiring is formed on a printed wiring board, and a flash plating layer is formed so as to cover a predetermined portion of the copper layer. Electronic components include SMD (Surface Mount Device) components which are surface mount components, DIP (Dual In Line Package) components in which lead terminals are inserted and fixed in through holes, and the like. In addition, the process of step S1 may be performed by a worker, and may be performed by an automatic working machine such as a robot.

In step S2, SMD components are mounted on the first surface of the printed wiring board. In addition, in step S3, the printed wiring board is turned over, and the SMD component is mounted on the second surface of the printed wiring board (the surface opposite to the first surface). Details will be described later. In the process of step S2, the solder plating layer is formed so as to cover the flash plating layer on the first surface of the printed wiring board, and in the process of step S3, the solder plating layer is formed to cover the second surface of the printed wiring board. Solder plating is formed by means of flash plating. In addition, the processes of these steps S2 and S3 are performed by a surface mounter (not shown) including a solder paste printing apparatus, a mounter, a reflow oven, and the like.

In step S4, DIP components are mounted on the second surface of the printed wiring board. In addition, in step S5, the printed wiring board is turned over, and the DIP component is mounted on the first surface of the printed wiring board. In addition, the process of these step S4 and step S5 is performed by the insertion installation machine (illustration omitted) provided with an insertion machine (it is unnecessary in the case of manual installation), a launder and the like.

In addition, in the above-mentioned steps S2 and S3, the SMD components are mounted in the order from the first surface to the second surface, and the DIP components are mounted in the order from the second surface to the first surface in the above-mentioned steps S4 and S5. The process of inverting the printed wiring board is reduced. In addition, the above-mentioned step S2 to step S5 correspond to the process of mounting a component on a board|substrate.

In step S6, the structural components are mounted on the printed circuit board (PCB) on which the SMD components and the DIP components are mounted. The "structural component" is, for example, a component other than an electronic component mounted on a board, such as a screw or a stud. In addition, the process of step S6 may be performed by a worker, and may be performed by an automatic working machine such as a robot.

In step S7 , the printed circuit board on which the structural components are mounted is assembled into the housing 3 of the electronic device 1 . Step S7 corresponds to the step of assembling the substrate into the frame. In addition, the installation of other internal equipment, wiring work, etc. are also performed. In addition, the process of step S7 may be performed by a worker, and may be performed by an automatic working machine such as a robot. In this way, the electronic device 1 is completed.

In the above, the case where the printed circuit board is a double-sided board with components mounted on both the front and the back has been described, but it may be a single-sided board with components mounted on only one side (component side). At this time, in the above-mentioned step S2, the SMD is not mounted, and the solder plating layer is formed so as to cover the flash plating layer of the first surface (solder surface). In the above-mentioned step S3, the SMD component is mounted on the second surface (component surface), and the solder plating layer is formed so as to cover the flash plating layer of the second surface (component surface). Then, in the above-mentioned step S4, the DIP component is mounted on the second surface (component surface). In addition, the above-mentioned step S5 is not required.

<3: Layer structure of printed wiring board>

Next, an example of the layer structure of the printed wiring board prepared in the above-mentioned step S1 will be described with reference to FIG. 3 . In addition, FIG. 3 is a cross-sectional view showing a cross-sectional structure of a through-hole portion of a printed wiring board extracted.

As shown in FIG. 3 , the printed wiring board 7 has a first surface 7A and a second surface 7B. In addition, the printed wiring board 7 has a substrate 9 (also referred to as a base material) made of an insulating material. The substrate 9 may be a substrate of a single-layer structure, or may be, for example, a substrate of a multilayer structure in which a wiring layer and a plane layer are laminated. In the substrate 9, through holes 11 are formed by a drilling machine in the drilling process. In addition, the "through hole" in this embodiment refers to a through hole with a large diameter formed so as to penetrate all layers of the substrate 9, for example, a lead terminal of a structural member such as a screw or a stud or a DIP member is inserted. Therefore, through holes with small diameters (so-called via holes) formed through all or only a part of the layers of the substrate 9 for the purpose of conduction between layers are not included in the "through holes".

On the surface of the board|substrate 9, the copper layer 12 is formed in a copper plating process and a pattern formation process. The copper layer 12 has a land portion 13 on the first surface 7A side and a land portion 15 on the second surface 7B side formed around the opening of the through hole 11 , and an inner wall portion formed on the inner wall of the through hole 11 17. In addition, the copper layer 12 has pads 19 on the side of the first surface 7A on which electronic components are to be surface-mounted, and pads 21 on the side of the second surface 7B, such as test pads or preparatory pads, on the first surface 7A on which no electronic components are mounted. The bonding pads 23 on the side, and the identification marks 25 formed on the side of the second surface 7B used for the placement machine or the interposer to detect the position or posture of the substrate.

Moreover, on the surface of the board|substrate 9, in a soldering resist process, the soldering resist layer 27 for protecting the said copper layer 12 is formed. The solder resist layer 27 is formed so as to cover other than predetermined portions of the copper layer 12 (for example, the pad portions 13 and 15 , the inner wall portion 17 , and the portions where the pads 19 and 21 are soldered. In addition, the pads 23 , the identification marks 25 , etc.) Pattern wiring (not shown) of the copper layer 12 .

The portion of the copper layer 12 exposed from the above-mentioned solder resist layer 27, that is, in the example shown in FIG. In the plating step, the flash plating layer 29 is formed so as to cover them. Flash plating is thin gold plating (for example, about 0.01 μm to 0.05 μm) performed in an extremely short period of time, has good compatibility with solder, and can ensure good wettability.

The printed wiring board 7 is manufactured, for example, through processes such as character printing, outline processing, and cleaning after the flash plating process described above.

<4.Detailed process of SMD installation>

Next, an example of a detailed process of the SMD mounting will be described with reference to FIGS. 4 to 10 .

FIG. 4 is a flowchart showing an example of a detailed process of the SMD mounting (first surface) performed in the above-mentioned step S2. In addition, FIG. 5 is a cross-sectional view showing the cross-sectional structure of the through hole portion of the printed wiring board corresponding to step S21 in FIG. 4 , and FIG. 6 is a cross-sectional view corresponding to step S22 in FIG. FIG. 7 is a cross-sectional view showing the cross-sectional structure of the hole portion, and FIG. 7 is a cross-sectional view showing the cross-sectional structure of the through-hole portion of the printed wiring board corresponding to step S23 in FIG. 4 .

As shown in FIG. 4 , in step S21 , solder paste is printed on the flash plating layer 29 on the first surface 7A side of the printed wiring board 7 by a solder paste printing apparatus using a metal mask. "Solder paste" is a substance obtained by adding a flux (solvent) to a powder of solder to obtain a predetermined viscosity, and is also referred to as a paste solder. For example, as shown in FIG. 5 , openings 35 are formed in the metal mask 31 at positions corresponding to the pads 13 , the pads 19 , and the pads 23 on the first surface 7A side, whereby the pads 13 , the solder paste 33 is printed on the flash plating layer 29 of the solder pad 19 and the solder pad 23 .

In step S22 , the SMD component is placed on the solder paste printed on the part where the component is mounted on the first surface 7A side of the printed wiring board 7 by the placement machine. For example, as shown in FIG. 6 , the SMD component 37 is arranged on the solder paste 33 printed on the flash plating layer 29 of the pad 19 .

In step S23, the printed wiring board 7 on which the SMD components 37 are arranged is heated in a reflow oven. Thereby, the printed solder paste 33 is melted by heating to cover the flash plating layer 29, and the SMD components 37 are joined by soldering. For example, as shown in FIG. 7 , the solder paste 33 printed on the flash plating layer 29 of the pad 19 is heated to vaporize the flux, and the powder of the solder is melted and liquefied, and then solidified to form the solder plating layer 39 . Thereby, the SMD component 37 and the flash plating layer 29 of the pad 19 are joined. Likewise, the solder paste 33 printed on the flash plating layer 29 of the pad 23 forms the solder plating layer 39 so as to cover the flash plating layer 29 by melting of the solder powder. In addition, the solder paste 33 printed on the flash plating layer 29 of the pad portion 13 is melted and liquefied, and flows into the through hole 11 . Thereby, the solder plating layer 39 is formed so as to cover a part of the flash plating layer 29 of the inner wall portion 17 (eg, half of the first surface 7A side) together with the flash plating layer 29 of the pad portion 13 .

FIG. 8 is a flowchart showing an example of a detailed process of the SMD mounting (second surface) performed in the above-mentioned step S3, and FIG. 9 is a cross-sectional structure corresponding to step S31 of FIG. 8, with a through hole portion of the printed wiring board extracted On the other hand, as for the sectional views shown, FIG. 10 is a sectional view corresponding to step S32 in FIG. 8 , showing the sectional structure of the through-hole portion of the printed wiring board, and FIG. 11 is a sectional view corresponding to step S33 in FIG. 8 , which is extracted A cross-sectional view showing a cross-sectional structure of a through-hole portion of a printed wiring board.

As shown in FIG. 8 , in step S31 , solder paste is printed on the flash plating layer 29 on the second surface 7B side of the printed wiring board 7 by a solder paste printing apparatus using a metal mask. For example, as shown in FIG. 9 , openings 43 are formed on the metal mask 41 at positions corresponding to the pad portions 15 , the pads 21 , and the identification marks 25 on the second surface 7B side, whereby the pad portions are formed with openings 43 . 15. Solder paste 33 is printed on the flash plating layer 29 of the solder pad 21 and the identification mark 25 .

In step S32 , the SMD component is placed on the solder paste printed on the part where the component is mounted on the second surface 7B side of the printed wiring board 7 by the placement machine. For example, as shown in FIG. 10 , the SMD component 45 is arranged on the solder paste 33 printed on the flash plating layer 29 of the pad 21 .

In step S33, the printed wiring board 7 on which the SMD components 45 are arranged is heated in a reflow oven. Thereby, the printed solder paste 33 is melted by heating to cover the flash plating layer 29, and the SMD components 45 are joined by soldering. For example, as shown in FIG. 11 , the solder paste 33 printed on the flash plating layer 29 of the pad 21 is heated to vaporize the flux, and the powder of the solder is melted and liquefied, and then solidified to form the solder plating layer 39 . Thereby, the SMD component 45 and the flash plating layer 29 of the pad 21 are joined. Similarly, the solder paste 33 printed on the flash plating layer 29 of the identification mark 25 forms the solder plating layer 39 so as to cover the flash plating layer 29 by melting of the solder powder. In addition, the solder paste 33 printed on the flash plating layer 29 of the pad portion 15 is melted and liquefied, and flows into the through hole 11 . Thereby, the solder plating layer 39 is formed so as to cover a part (eg, half of the second surface 7B side) of the flash plating layer 29 of the inner wall portion 17 together with the flash plating layer 29 of the pad portion 15 . In this way, by performing the SMD component mounting process on both the first surface 7A and the second surface 7B of the printed wiring board 7 , the solder plating layer 39 is formed so as to cover the entire flash plating layer 29 of the inner wall portion 17 in the through hole 11 . .

In the above, the case where the entire inner wall portion 17 is covered with the solder paste 33 of the pad portion 13 and the pad portion 15 at the same ratio has been described. For example, only the pad portion 13 or the pad portion 15 may be used. Either one of the solder pastes 33 may cover the entire inner wall portion 17 , and the entire inner wall portion 17 may be covered with the solder pastes 33 of the pad portion 13 and the pad portion 15 at an appropriate ratio. In this case, for example, the thickness of the metal masks 31 and 41 and the size of the openings 35 and 43 are adjusted, and the amount of the solder paste 33 printed on the pad portion 13 or the pad portion 15 is adjusted to an appropriate amount, that is, Can.

In addition, the above-mentioned step S21 and step S31 correspond to the process of printing solder paste and the process of printing solder paste on the flash plating layer of the pad portion. In addition, the above-mentioned step S23 and step S33 correspond to the step of covering the flash plating layer and the step of covering the flash plating layer of the pad portion and the inner wall portion. In addition, the above-mentioned step S21 and step S31, step S23 and step S33 correspond to the process of forming a solder plating layer.

<5.Detailed process of DIP installation>

Next, an example of a detailed process of the DIP mounting will be described with reference to FIGS. 12 to 15 .

FIG. 12 is a flowchart showing an example of a detailed process of the DIP mounting (second surface) performed in the above-mentioned step S4, and FIG. 13 is a cross-sectional structure corresponding to step S41 in FIG. 12, in which the through-hole portion of the printed wiring board is extracted On the other hand, among the cross-sectional views shown, FIG. 14 is a cross-sectional view corresponding to step S42 in FIG. 12 , which extracts the cross-sectional structure of the through-hole portion of the printed wiring board and shows it.

As shown in FIG. 12 , in step S41 , the DIP components are arranged on the part where the components are mounted on the second surface 7B side of the printed wiring board 7 by the insertion machine or the manual work of the operator. For example, as shown in FIG. 13 , the DIP member 47 is arranged on the second surface 7B side by inserting the lead terminal 49 into the through hole 51 . In addition, the through hole 51 covers the land portion 53 by performing the SMD component mounting process (step S2 and step S3 ) on both the first surface 7A and the second surface 7B of the printed wiring board 7 as in the above-described through hole 11 . , 55 , and the entire flash plating layer 29 of the inner wall portion 57 is formed with a solder plating layer 39 .

In step S42, flow soldering is performed on the printed wiring board 7 on which the DIP components 47 are arranged using a flow cell. Thereby, the lead terminal 49 of the DIP member 47 is joined to the through hole 51 by soldering. For example, as shown in FIG. 14 , a jet of solder is sprayed from the runner to the first surface 7A side of the printed wiring board 7 on which the DIP components 47 are arranged on the second surface 7B side, the solder fills the through holes 51, and forms Solder foot 59.

In step S43 , the operator manually welds the portion that has not been welded by the flow welding, or performs repair of the portion where a defect (for example, a short circuit or the like) occurs by the flow welding. In addition, the process of step S43 may be performed by an automatic working machine such as a robot.

FIG. 15 is a flowchart showing an example of a detailed process of the DIP mounting (first surface) performed in the above-mentioned step S5. In addition, the cross-sectional structure of the printed wiring board in this step is the same as that shown in FIGS. 13 and 14 (the printed wiring board is turned upside down, and the positional relationship in the vertical direction of the first surface and the second surface is reversed), so the cross-sectional structure is omitted. Show.

As shown in FIG. 15, in step S51, the lead terminal of the DIP member is inserted into the through hole by the insertion machine or the manual operation of the operator, and the DIP member is arranged on the side of the first surface 7A.

In step S52, a jet of solder is sprayed from the runner to the second surface 7B side of the printed wiring board 7 on which the DIP components are arranged on the first surface 7A side, the solder fills the through holes, and fillets are formed.

In step S53 , the operator manually welds the portion that has not been welded by the flow welding, or repairs the portion where a defect (for example, a short circuit or the like) occurs by the flow welding. In addition, the process of step S53 may be performed by an automatic working machine such as a robot. Thereby, the mounting of the components on the printed wiring board 7 is completed, and the printed circuit board 5 is obtained.

As described above, on the land portions 53 and 55 and the inner wall portion 57 of the through hole 51 in which the DIP component 47 is mounted, the solder plating layer 39 is formed in advance so as to cover the flash plating layer 29 in the preceding process (the SMD component mounting process). . Thereby, flash plating can also be prevented on the land portion 55 (the land portion 55 on the side where the DIP member 47 is arranged) and the portion of the inner wall portion 57 where the solder does not reach the side opposite to the side where the flow soldering is performed. 29 exposed.

<6. Structural parts mounted on the printed circuit board>

Next, an example of the component mounted on the printed circuit board in the above-mentioned step S6 will be described with reference to FIG. 16 .

In the example shown in FIG. 16 , screws 62 are inserted into the through holes 61 of the printed circuit board 5 on which the components have been mounted from the first surface 7A side to the second surface 7B side, and are screwed into the studs 64 . In addition, the through hole 61 covers the land portion by performing the SMD component mounting process (step S2 and step S3 ) on both the first surface 7A and the second surface 7B of the printed wiring board 7 as in the above-mentioned through holes 11 and 51 . The solder plating layer 39 is formed integrally with the flash plating layer 29 of the inner wall portion 67 , 63 , 65 . The screw 62 and the stud 64 made of conductive material are connected by being fastened to each other. In addition, the screw 62 is in contact with the solder plating layer 39 via the washer 69 to be in conduction with the land portion 63 , and the stud 64 is in contact with the solder plating layer 39 to be in conduction with the land portion 65 .

With such a configuration, the following effects are achieved. For example, as a method of suppressing the corrosion of the flash plating layer 29, it is possible to apply a coating material (acrylic, urethane, silicon, etc.) to the surface of the flash plating layer 29, for example. However, in this case, since the coating material is made of an insulating material, the insulating material is interposed between the screw 62 or the stud 64 and the land portions 63 and 65, and there is a possibility that the conduction in the through hole 61 may become unstable. In the present embodiment, since the solder plating layer 39 which is a conductive material is formed, good conduction between the screw 62 , the stud 64 and the pad parts 63 and 65 can be ensured, and the stability of conduction of the through hole 61 can be improved. sex.

<7. Effects of Embodiment>

As described above, the electronic device 1 of the present embodiment includes the printed circuit board 5 including: the substrate 9; the copper layer 12 formed on the substrate 9; the flash plating layer 29 formed to cover a predetermined portion of the copper layer 12; and solder The plating layer 39 is formed to cover the flash plating layer 29 .

By employing flash plating as the surface treatment of the copper layer 12 , compared to the case where the surface of the copper layer 12 is covered with solder (solder leveler), for example, it is possible to mount an extremely small chip component, a narrow pitch BGA (package), and the like, and it is possible to realize Densification or miniaturization of the printed circuit board 5 . On the other hand, since the flash plating layer 29 is formed very thin, it tends to corrode easily in an environment of corrosive gas such as hydrogen sulfide gas compared with a solder leveler, and good environmental resistance may not be obtained.

Therefore, in this embodiment, the solder plating layer 39 is formed so as to cover the flash plating layer 29 . Thereby, since the corrosion resistance of the solder to corrosive gases is high, the environmental resistance of the flash plating layer 29 can be improved. Therefore, it is possible to realize the printed circuit board 5 having high density and miniaturization and high environmental resistance.

In addition, as a method of suppressing the corrosion of the flash plating layer 29, for example, applying a coating material (acrylic, urethane, silicon, etc.) can be considered. However, since such a coating material is composed of an insulating material, there is a possibility of forming a flash plating layer. There is a possibility that the conduction of the part 29 becomes unstable. In the present embodiment, since the solder plating layer 39 made of a conductive material is formed, good conduction can be ensured.

In the present embodiment, in particular, the copper layer 12 includes the pad portions 13 and 15 formed around the openings of the through holes 11 and the like (including the through holes 51 and 61 . The same applies hereinafter) formed in the substrate 9 . (including land parts 53, 55, land parts 63, 65; the same below) and the inner wall part 17 (including the inner wall parts 57, 67; the same below) formed on the inner wall of the through hole 11 and the like, the flash plating layer 29 is formed The solder plating layer 39 is formed to cover the flash plating layer 29 formed on the pad portions 13 , 15 , etc. and the inner wall portion 17 , etc. in order to cover the pad portions 13 , 15 , etc., and the inner wall portion 17 , etc.

The through-holes 11 and the like formed in the substrate are inserted through, for example, screws 62 or studs 64 for fixing components or as terminals of the substrate, or through the lead terminals 49 of the DIP components 47 for mounting the components. Assuming that the solder plating layer 39 is not formed, the former through holes (for example, the through hole 61 ) are generally not coated, so the flash plating layer 29 is exposed at the pad portions 63 and 65 or the inner wall portion 67 or the like. In the latter through holes (for example, through holes 51 ), molten solder is sprayed from the surface side opposite to the surface on which the DIP components 47 are arranged in the solder flow process to mount the DIP components 47 . The flash plated layer 29 may be exposed at the portion of the land portion 55 and the inner wall portion 57 on the surface side where the solder does not reach. Therefore, it is easily affected by corrosive gas.

In the present embodiment, the solder plating layer 39 is formed to cover the flash plating layer 29 formed on the pad portions 13 and 15 and the like and the inner wall portion 17 and the like of the copper layer 12 . Thereby, the exposed portion of the flash plating layer 29 can be eliminated in the through holes of the above two types, and the environmental resistance can be improved.

In addition, in the case of applying, for example, a coating material to the exposed portion of the flash plating layer 29 in the through hole 11 or the like, since the coating material is composed of an insulating material, the insulating material is interposed between the screws 62 and the studs 64 inserted therein. , or between the lead terminal 49 of the DIP member 47 and the copper layer 12, there is a possibility that the conduction of the through hole 11 or the like may become unstable. On the other hand, in this embodiment, a solder plated layer as a conductive material is formed. 39, the stability of conduction of the through hole 11 and the like can be improved.

Moreover, in the manufacturing method of the electronic device 1 provided with the printed circuit board 5 of the present embodiment, there are steps S2 to S5 in which the printed wiring board 7 on which the flash plating layer 29 is formed so as to cover a predetermined portion of the copper layer 12 The process of mounting the components; and the step S7, which is a process of assembling the printed circuit board 5 on which the components are mounted into the frame 3, and the steps S2 to S5 as the process of mounting the components to the printed wiring board 7 include steps S2 to S5 as a process to cover the flash plating layer 29 Step S21 and Step S31 and Step S23 and Step S33 of the process of forming the solder plating layer 39 in the same manner.

Thereby, the process of forming the solder plating layer 39 can be incorporated into the process of the mounting member which is a conventional manufacturing process. Therefore, it is possible to manufacture the electronic device 1 including the printed circuit board 5 which can be increased in density and size and has high environmental resistance without adding a new manufacturing process.

In addition, in this embodiment, in particular, the steps S21 and S31, and the steps S23 and S33, which are the steps of forming the solder plating layer 39, include steps S21 and S31, in which the metal masks 31 and 41 are used in the flash plating layer 29. The process of printing the solder paste 33 on top; and steps S23 and S33 are processes of melting the printed solder paste 33 by heating and covering the flash plating layer 29 .

Usually, the steps of mounting the SMD components 37 and 45 include: even if the solder plating layer 39 is not formed, the steps of printing solder paste on a predetermined part of the substrate using a metal mask (corresponding to steps S21 and S31 ); Steps of arranging components on the printed solder paste (corresponding to steps S22 and S32 ); steps of melting the printed solder paste by heating and fixing the components with solder (corresponding to steps S23 and S33 ). Therefore, according to the present embodiment, it is possible to form solder on the flash plated layer 29 in the process of mounting the SMD components 37 and 45 by simply providing the opening of the portion where the solder plated layer 39 is to be formed in the opening shape of the existing metal mask. Plating 39.

In the present embodiment, in particular, Step S21 and Step S31, which are processes of printing the solder paste 33, include a process of printing the solder paste 33 on the flash plating layers 29 of the pad portions 13, 15, etc., as the process of covering the flash plating layers 29. Steps S23 and S33 of the process include a step of melting the solder paste 33 printed on the flash plating layer 29 of the pad parts 13 and 15 and the like by heating to cover the flash plating layer 29 of the pad parts 13 and 15 and the like and the inner wall part 17 and the like. .

In this way, the solder paste 33 printed on the pad portions 13, 15, etc. is melted, and the liquid solder flows into the inside of the through-hole 11, etc., so that not only the pad portions 13, 15, etc., but also the inner wall portion 17, etc. flicker. Plating 29 may also be covered with solder plating 39 .

<8. Modifications>

In addition, the disclosed embodiment is not limited to the content mentioned above, Various deformation|transformation is possible in the range which does not deviate from the summary and technical idea.

In the above-described embodiment, the solder paste 33 is printed on both the land portions 53 and 55 of the through hole 51 and heated by a reflow oven so as to cover the entire flash plating layer 29 of the land portions 53 and 55 and the inner wall portion 57 . The solder plating layer 39 is formed in the manner of, but not limited to. For example, as shown in FIG. 17 , only the pad portion 55 of the through hole 51 may be printed with the solder paste 33 and heated in a reflow oven so as to cover the flash plating of the inner wall portion 57 together with the flash plating layer 29 of the pad portion 55 . The solder plating layer 39 is formed so as to be part of the plating layer 29 (eg, half of the second surface 7B side). Furthermore, as shown in FIG. 18 , a jet of solder may be sprayed from the runner to the first surface 7A side of the printed wiring board 7 on which the DIP member 47 is arranged on the second surface 7B side, and the through hole 51 may be filled with the solder. At the same time, the solder fillet 59 is formed to cover the pad portion 53 and the remaining portion of the inner wall portion 57 (eg, half of the first surface 7A side) of the flash plating layer 29 .

In addition, in the case of this modification, in the above-mentioned step S21 shown in FIG. 4 , the printing of the solder paste 33 is not performed on the pad portion 53 on the side of the first surface 7A, and in the above-mentioned step S31 shown in FIG. 8 , The solder paste 33 may be printed on the pad portion 55 on the second surface 7B side. According to this modification, the pad portion 55 (the pad portion 55 on the side where the DIP member 47 is arranged) and the portion of the inner wall portion 57 that is difficult for solder to reach (for example, the second surface) 7B side), the flash plating layer 29 can also be prevented from being exposed.

In addition, in the above description, when there are descriptions such as "perpendicular", "parallel", "planar", etc., the description does not mean strictly. That is, these "perpendicular", "parallel", and "plane" allow tolerances and errors in manufacturing in design, and refer to "substantially perpendicular", "substantially parallel", and "substantially plane".

In addition, in the above description, when there are descriptions such as "same (same)", "equal", "different", etc. in terms of dimensions, size, shape, and position in appearance, the description does not mean strictly. That is, these "same (same)", "equal" and "different" allow tolerances and errors in design and manufacture, and refer to "substantially the same (same)", "substantially equal" and "substantially different" .

In addition to the methods already described above, the methods of the above-described embodiment or each modification example may be appropriately combined and utilized. In addition, although not illustrated one by one, the said embodiment and each modification can be implemented by adding various changes in the range which does not deviate from the summary.

1 Electronic equipment

3 Frames

5 Printed substrate

7 Printed wiring board (substrate)

9 Substrate

11 Through hole

12 copper layers

13 Land part

15 Pad part

17 Inner wall

29 Flash Plating

31 Metal mask

33 Solder Paste

39 Solder Plating

41 Metal mask

51 through hole

53 Pad part

55 Pad part

57 Inner wall

61 through hole

63 Pad part

65 Pad part

67 Inner wall

Claims (7)

1. An electronic device comprising a printed circuit board, wherein the electronic device is characterized in that: The printed substrate has: substrate; a copper layer formed on the substrate; a flash plating layer formed to cover a predetermined portion of the copper layer; and A solder plating layer is formed to cover the flash plating layer. 2. The electronic device according to claim 1, characterized in that, The copper layer has: a pad portion formed around an opening portion of a through hole formed in the substrate; and an inner wall portion formed on the inner wall of the through hole, The flash plating layer is formed to cover the pad portion and the inner wall portion, The solder plating layer is formed to cover the flash plating layer, and the flash plating layer is formed on the pad portion and the inner wall portion. 3. A method of manufacturing an electronic device comprising a printed circuit board, the manufacturing method comprising the following steps: mounting the component on a substrate on which a flash plating layer is formed so as to cover a predetermined portion of the copper layer; and assembling the board with the components mounted in the frame, The step of mounting the component on the substrate includes a step of forming a solder plating layer so as to cover the flash plating layer. 4. The method for manufacturing an electronic device according to claim 3, wherein the step of forming the solder plating layer comprises the following steps: printing solder paste on the flash layer using a metal mask; and The printed solder paste is heated and melted to cover the flash coating. 5. The manufacturing method of an electronic device according to claim 4, wherein, The copper layer has: a pad portion formed around an opening portion of a through hole formed in the substrate; and an inner wall portion formed on the inner wall of the through hole, The flash plating layer is formed to cover the pad portion and the inner wall portion, The step of printing the solder paste includes the step of printing the solder paste on the flash plating layer of the pad portion, The step of covering the flash plating layer includes a step of heating and melting the solder paste printed on the flash plating layer of the pad portion to cover the flash plating layer of the pad portion and the inner wall portion. 6. A printed circuit board, characterized in that the printed circuit board has: substrate; a copper layer formed on the substrate; a flash plating layer formed to cover a predetermined portion of the copper layer; and A solder plating layer is formed to cover the flash plating layer. 7. A method of manufacturing a printed circuit board, the manufacturing method characterized by: having a step of mounting components on a substrate on which a flash plating layer is formed so as to cover a predetermined portion of the copper layer, The step of mounting the component on the substrate includes a step of forming a solder plating layer so as to cover the flash plating layer.

Images