CN111836474B - Electronic device and method for manufacturing the same, and printed board and method for manufacturing the same - 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. The electronic device (1) is provided with a printed substrate (5), and the printed substrate (5) is provided with a substrate (9); a copper layer (12) formed on the substrate (9); flash layer (29) formed to cover pad portions (13, 15) of the through hole (11) and an inner wall portion (17) of the through hole (11) in the copper layer (12); and a solder plating layer (39) formed so as to cover the flash plating layer (29).

Description

Electronic equipment and manufacturing method thereof, and printed substrate and manufacturing method thereof

Technical field

The disclosed embodiments relate to electronic devices, methods of manufacturing electronic devices, printed circuit boards, and methods of manufacturing printed circuit boards.

Background technique

Patent Document 1 describes a method of manufacturing a printed wiring board using flash plating.

Prior technical documents

patent documents

Patent Document 1: Japanese Patent Application Publication No. 2009-152483.

Contents of the invention

Problems to be solved by inventions

A substrate subjected to flash plating may not have good environmental resistance, for example, in a corrosive gas environment, and improvement in environmental resistance is required.

The present invention was made in view of such problems, and an object thereof is to provide an electronic device, a manufacturing method of an electronic device, a printed circuit board, and a method of manufacturing a printed circuit board that can improve environmental resistance.

Methods used to solve problems

In order to solve the above problems, according to one aspect of the present invention, an electronic device is provided with a printed circuit board. The printed circuit board has: a substrate; a copper layer formed on the substrate; and a flash plating layer formed to cover the copper layer. a prescribed portion; and a solder plating layer formed to cover the flash plating layer.

In addition, according to another aspect of the present invention, a manufacturing method of an electronic device provided with a printed circuit board is applied, and the manufacturing method includes the following steps: mounting a component on the substrate and covering the substrate with a copper layer and assembling the substrate with the component mounted on the frame into a frame. The step of mounting the component to the substrate includes the step of forming a solder plating layer to cover the flash layer.

In addition, according to another aspect of the present invention, a printed circuit board is used and is mounted on an electronic device. The printed circuit board has: a substrate; a copper layer formed on the substrate; and a flash plating layer formed to cover the copper layer. a prescribed location; and a solder plating layer formed to cover the flash plating layer.

In addition, according to another aspect of the present invention, a method of manufacturing a printed circuit board mounted on an electronic device is applied, the manufacturing method having a step of mounting components to the substrate, and the substrate is covered with a copper layer. A flash plating layer is formed at a predetermined location, 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 equipment and the like of the present invention, environmental resistance can be improved.

Description of drawings

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

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

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

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

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

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

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 of FIG. 4 ;

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

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

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

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

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

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

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

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

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

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

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

Detailed ways

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

<1. General structure of electronic equipment>

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

As shown in FIG. 1 , the electronic device 1 has a housing 3 and a plurality of (for example, five) printed circuit boards 5 . Each printed circuit board 5 is erected in a direction perpendicular to the bottom plate 3 a of the frame 3 via a connector (not shown), and is arranged parallel to each other. In addition, the number of printed circuit boards 5 mounted on the electronic device 1 is not limited to a plurality and may be a single one. In addition, the printed circuit board 5 may be provided parallel 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 equipped with a printed circuit board. For example, it can also be applied to control devices that control drive machinery other than motors, various industrial equipment, computers, and smartphones.

In addition, the "printed circuit board" in this embodiment is not the so-called printed wiring board (PWB: Printed Wiring Board) before mounting electronic components, but refers to the so-called printed circuit 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 the manufacturing process (manufacturing method) of the electronic device according to this embodiment will be described with reference to FIG. 2 .

In step S1, a printed wiring board (PWB), electronic components mounted on the printed wiring board, and the like are prepared. As will be described in detail 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 that are surface mount components, DIP (Dual In line Package) components that are fixed by inserting lead terminals into through holes, and the like. In addition, the process of step S1 may be performed by an operator or may be performed by an automatic working machine such as a robot.

In step S2, the SMD component is mounted on the first surface of the printed wiring board. Furthermore, 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, a solder plating layer is formed to cover the flash plating layer on the first surface of the printed wiring board. In the process of step S3, a solder plating layer is formed to cover the second surface of the printed wiring board. Solder coating is formed by flash plating. In addition, these steps S2 and S3 are performed by a surface mount machine (not shown) including a solder paste printing device, a mounting machine, a reflow furnace, and the like.

In step S4, the DIP component is 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, these steps S4 and S5 are performed by an insertion mounting machine (not shown) including an insertion machine (not necessary in the case of manual mounting) and a launder.

In addition, in the above-mentioned steps S2 and step S3, the SMD components are mounted in the order from the first surface to the second surface, and in the above-mentioned steps S4 and step S5, the DIP components are mounted in the order from the second surface to the first surface. Reduce the process of turning over printed wiring boards. In addition, the above-mentioned steps S2 to step S5 correspond to the process of mounting components on the 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. "Structural components" are, for example, components other than electronic components mounted on the substrate such as screws and studs. In addition, the process of step S6 may be performed by an operator or 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 process of assembling the substrate into the frame. In addition, the installation and wiring of other internal equipment are also performed. In addition, the process of step S7 may be performed by an operator or may be performed by an automatic working machine such as a robot. In this way, the electronic device 1 is completed.

In the above description, the printed circuit board is a double-sided circuit board with components mounted on both the front and back surfaces. However, the printed circuit board may be a single-sided circuit board with components mounted on only one side (component side). At this time, in step S2 described above, the SMD is not mounted, and the solder plating layer is formed so as to cover the flash plating layer on the first surface (solder surface). In step S3 described above, the SMD component is mounted on the second surface (component surface), and a solder plating layer is formed so as to cover the flash plating layer on the second surface (component surface). Furthermore, in step S4 described above, 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 step S1 will be described with reference to FIG. 3 . In addition, FIG. 3 is a cross-sectional view showing the cross-sectional structure of the through-hole portion of the printed wiring board.

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 a substrate of a multi-layer structure in which a wiring layer and a plane layer are laminated. On the substrate 9 , the through hole 11 is formed by a drilling machine in the hole drilling process. In addition, the “through hole” in this embodiment refers to a through hole with a large diameter formed to penetrate all layers of the substrate 9 , for example, into which structural components such as screws and studs or lead terminals of DIP components are inserted. Therefore, through-holes (so-called via holes) with a small diameter that are formed through all or only part of the layers of the substrate 9 for the purpose of inter-layer conduction are not included in the “through holes”.

The copper layer 12 is formed on the surface of the substrate 9 in the copper plating process and the pattern forming process. The copper layer 12 has a pad portion 13 on the first surface 7A side and a pad 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 first surface 7A side where electronic components are to be mounted, and pads 21 on the second surface 7B side, such as test pads or preliminary pads on the first surface 7A where electronic components are not mounted. The soldering pads 23 on the second surface 7B and the identification mark 25 formed on the second surface 7B side are used for mounting machines or insertion machines to detect the position or posture of the substrate.

In addition, a solder resist layer 27 for protecting the copper layer 12 is formed on the surface of the substrate 9 during the solder resist process. The solder resist layer 27 is formed to cover except for predetermined portions of the copper layer 12 (for example, the pad portions 13 and 15, the inner wall portions 17 and the bonding pads 19 and 21, etc., where soldering is performed. In addition, the bonding pad 23, the identification mark 25, etc.) Pattern wiring of copper layer 12 (not shown).

On the parts of the copper layer 12 that are exposed from the solder resist layer 27, that is, in the example shown in FIG. In the plating process, the flash plating layer 29 is formed to cover them. Flash plating is a thin gold plating (for example, about 0.01 μm to 0.05 μm) that is performed in a very short time. It has good compatibility with solder and can ensure good wettability.

The printed wiring board 7 is manufactured through processes such as character printing, shape processing, and cleaning after the flash plating process.

<4. Detailed process of SMD installation>

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

FIG. 4 is a flowchart showing an example of the detailed process of SMD mounting (first surface) performed in 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 extracted corresponding to step S21 of FIG. 4 , and FIG. 6 is corresponding to step S22 of FIG. 4 . 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 of 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 using a metal mask using a solder paste printing device. "Solder paste" is a substance obtained by adding flux (solvent) to solder powder to obtain a predetermined viscosity. It is also called paste solder. For example, as shown in FIG. 5 , openings 35 are formed in the metal mask 31 at positions corresponding to the pad portion 13 , the pads 19 , and the pads 23 on the first surface 7A side, so that the pad portion 13 , 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 component mounting portion on the first surface 7A side of the printed wiring board 7 using a mounting machine. For example, as shown in FIG. 6 , the SMD component 37 is arranged on the solder paste 33 printed on the flash layer 29 of the bonding pad 19 .

In step S23, the printed wiring board 7 on which the SMD component 37 is arranged is heated in a reflow oven. Thereby, the printed solder paste 33 is melted by heating, covers the flash layer 29 , and the SMD component 37 is joined by soldering. For example, as shown in FIG. 7 , the solder paste 33 printed on the flash plating layer 29 of the bonding pad 19 is heated to vaporize the flux, and the solder powder melts and liquefies, and then solidifies to form the solder plating layer 39 . Thereby, the SMD component 37 and the flash layer 29 of the bonding pad 19 are bonded. Similarly, the solder paste 33 printed on the flash plating layer 29 of the bonding pad 23 forms a solder plating layer 39 by melting the solder powder so as to cover the flash plating layer 29 . In addition, the solder paste 33 printed on the flash plating layer 29 of the pad portion 13 melts and liquefies, and flows into the through hole 11 . Thus, 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 (for example, 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 the detailed process of SMD mounting (second surface) performed in step S3. FIG. 9 is a cross-sectional structure corresponding to step S31 of FIG. 8 and extracting the through-hole portion of the printed wiring board. As for the cross-sectional views shown, FIG. 10 is a cross-sectional view corresponding to step S32 of FIG. 8 , showing the extracted cross-sectional structure of the through-hole portion of the printed wiring board, and FIG. 11 is a cross-sectional view corresponding to step S33 of FIG. 8 . A cross-sectional view showing the cross-sectional structure of the through-hole portion of the 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 using a metal mask using a solder paste printing device. For example, as shown in FIG. 9 , openings 43 are formed in the metal mask 41 at positions corresponding to the pad portion 15 , the bonding pad 21 and the identification mark 25 on the second surface 7B side, whereby the pad portion 15. Print solder paste 33 on the flash plating layer 29 of the soldering pad 21 and the identification mark 25 .

In step S32, the SMD component is placed on the solder paste printed on the component mounting portion on the second surface 7B side of the printed wiring board 7 using a mounting machine. For example, as shown in FIG. 10 , the SMD component 45 is arranged on the solder paste 33 printed on the flash layer 29 of the bonding pad 21 .

In step S33, the printed wiring board 7 on which the SMD component 45 is arranged is heated in a reflow oven. Thereby, the printed solder paste 33 is melted by heating, covers the flash layer 29 , and the SMD component 45 is joined by soldering. For example, as shown in FIG. 11 , the solder paste 33 printed on the flash plating layer 29 of the bonding pad 21 is heated to vaporize the flux, and the solder powder melts and liquefies, and then solidifies to form the solder plating layer 39 . Thereby, the SMD component 45 and the flash plating layer 29 of the bonding pad 21 are bonded. Similarly, the solder paste 33 printed on the flash plating layer 29 of the identification mark 25 forms a solder plating layer 39 by melting the solder powder so as to cover the flash plating layer 29 . In addition, the solder paste 33 printed on the flash layer 29 of the pad portion 15 melts and liquefies, and flows into the through hole 11 . Thus, 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 (for example, half of the second surface 7B side) 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 addition, in the above description, 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, but for example, only the pad portion 13 or the pad portion 15 may be used. Any one of the solder pastes 33 covers the entire inner wall portion 17 , or the entire inner wall portion 17 may be covered with the solder paste 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 or the size of the openings 35 and 43 is adjusted to adjust the amount of the solder paste 33 printed on the pad portion 13 or the pad portion 15 to an appropriate amount. Can.

In addition, the steps S21 and S31 described above 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 steps S23 and S33 described above correspond to the process of covering the flash plating layer and the process of covering the flash plating layer of the pad portion and the inner wall portion. In addition, the above-described steps S21, S31, S23, and S33 correspond to the process of forming a solder plating layer.

<5.Detailed procedures for DIP installation>

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

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

As shown in FIG. 12 , in step S41 , the DIP component is arranged on the component mounting portion on the second surface 7B side of the printed wiring board 7 through an insertion machine or manual work by an operator. For example, as shown in FIG. 13 , the DIP component 47 is arranged on the second surface 7B side by inserting the lead terminal 49 into the through hole 51 . In addition, like the above-described through hole 11 , the through hole 51 covers the pad 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 . , 55 and the flash plating layer 29 of the inner wall portion 57 are integrally formed with a solder plating layer 39 .

In step S42, flow soldering is performed on the printed wiring board 7 on which the DIP component 47 is arranged using a launder. Thereby, the lead terminal 49 of the DIP component 47 is joined to the through hole 51 by soldering. For example, as shown in FIG. 14 , a jet stream of solder is ejected from the launder to the first surface 7A side of the printed wiring board 7 on which the DIP component 47 is arranged on the second surface 7B side. The solder is filled into the through hole 51 and forms Welding feet 59.

In step S43, the operator performs manual welding on the portions that have not been soldered by the flow soldering, or performs repair of portions where defects (such as short circuits, etc.) have occurred by the flow soldering. In addition, the process of step S43 may also be performed by an automatic working machine such as a robot.

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

As shown in FIG. 15 , in step S51 , the lead terminals of the DIP component are inserted into the through holes using an insertion machine or manual work by an operator, and the DIP component is arranged on the first surface 7A side.

In step S52, a jet stream of solder is ejected from the launder to the second surface 7B side of the printed wiring board 7 on which the DIP component is arranged on the first surface 7A side, and the solder is filled into the through hole to form a solder fillet.

In step S53, the operator manually welds the portions that have not been soldered by the flow soldering, or repairs the portions that have caused defects (eg, short circuits, etc.) by the flow soldering. In addition, the process of step S53 may also be performed by an automatic working machine such as a robot. Thereby, the mounting of the component to the printed wiring board 7 is completed, and it becomes the printed circuit board 5.

As described above, the solder plating layer 39 is formed in advance on the pad portions 53 and 55 and the inner wall portion 57 of the through hole 51 on which the DIP component 47 is mounted to cover the flash plating layer 29 in the previous step (SMD component mounting step). . Accordingly, it is possible to prevent the flash plating layer from forming on the pad portion 55 on the side opposite to the side where the flow soldering is performed (the pad portion 55 on the side where the DIP component 47 is disposed) and the portion of the inner wall portion 57 where the solder does not reach it. 29 exposed.

<6. Structural components mounted on printed circuit boards>

Next, an example of the structural components mounted on the printed circuit board in 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 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, like the above-mentioned through holes 11 and 51 , the through hole 61 covers the pad 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 63, 65 and the flash plating layer 29 of the inner wall portion 67 are integrally formed with a solder plating layer 39. The screw 62 and the stud 64, which are made of conductive material, are electrically connected by being fastened to each other. In addition, the screw 62 is in contact with the solder plating 39 via the washer 69 and is electrically connected to the pad portion 63 , and the stud 64 is in contact with the solder plating 39 and is electrically connected to the pad portion 65 .

Such a structure achieves the following effects. For example, as a method of suppressing corrosion of the flash plating layer 29 , it is conceivable to apply a coating material (acrylic-based, polyurethane-based, silicon-based, etc.) to the surface of the flash plating layer 29 . However, in this case, since the coating material is made of an insulating material, the insulating material is interposed between the above-mentioned screws 62 or studs 64 and the pad portions 63 and 65, and the conduction in the through hole 61 may become Unstable. In this embodiment, since the solder plating 39 as a conductive material is formed, good conduction between the screws 62 and studs 64 and the pad portions 63 and 65 can be ensured, and the stability of the conduction of the through hole 61 can be improved. sex.

<7. Effects of implementation>

As described above, the electronic device 1 of this embodiment is provided with the printed circuit board 5 . The printed circuit board 5 includes 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 using flash plating as the surface treatment of the copper layer 12, it is possible to mount extremely small chip components or narrow-pitch BGA (package), etc., compared to a case where the surface of the copper layer 12 is covered with solder (solder leveler). High density 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 gases such as hydrogen sulfide gas compared to 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 . As a result, the solder has high corrosion resistance to corrosive gases, so the environmental resistance of the flash layer 29 can be improved. Therefore, it is possible to realize a printed circuit board 5 that is denser and smaller and has high environmental resistance.

In addition, as a method of suppressing the corrosion of the flash plating layer 29, it is also possible to apply a coating material (acrylic type, polyurethane type, silicon type, etc.). However, since such a coating material is composed of an insulating material, there is a problem in forming the flash plating layer. 29, the conduction may become unstable. In this embodiment, since the solder plating layer 39 made of a conductive material is formed, good conduction can be ensured.

In addition, in this embodiment, in particular, the copper layer 12 has 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 below) formed on the substrate 9 (Including pad portions 53 and 55 and pad portions 63 and 65. The same applies below) and the inner wall portion 17 formed on the inner wall of the through hole 11 and the like (including the inner wall portions 57 and 67. The same applies below), and 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 and 15 and the like and the inner wall portion 17 and the like.

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

In this embodiment, the solder plating layer 39 is formed as the flash plating layer 29 covering 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 two through holes, 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 layer 29 in the through hole 11 etc., since the coating material is composed of an insulating material, the insulating material is interposed between the screws 62 and studs 64 inserted inside. , or the conduction between the lead terminal 49 of the DIP component 47 and the copper layer 12 may become unstable through the through hole 11 or the like. In contrast, in this embodiment, the solder plating layer as a conductive material is formed. 39, it is possible to improve the conduction stability of the through hole 11 and the like.

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

Thereby, the process of forming the solder plating layer 39 can be integrated into the component mounting process which is an existing manufacturing process. Therefore, it is possible to manufacture the electronic device 1 including the printed circuit board 5 that is capable of high density and miniaturization and has high environmental resistance without adding a new manufacturing process.

In addition, in this embodiment, in particular, steps S21 and S31 and steps S23 and S33, which are steps of forming the solder plating layer 39, include: steps S21 and S31. The metal masks 31 and 41 are used to form the flash plating layer 29. The steps of printing the solder paste 33 and steps S23 and S33 are steps of melting the printed solder paste 33 by heating to cover the flash plating layer 29 .

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

In addition, in this embodiment, in particular, steps S21 and S31 which are steps of printing the solder paste 33 include a step of printing the solder paste 33 on the flash plating layer 29 of the pad portions 13, 15 and the like. As a step of covering the flash plating layer 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 portions 13 and 15 and the like by heating to cover the flash plating layer 29 of the pad portions 13 and 15 and the inner wall portion 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 through hole 11, etc., thereby causing flashing of not only the pad portions 13, 15, etc., but also the inner wall portion 17, etc. The plating 29 can also be covered with a solder plating 39 .

<8.Modification>

In addition, the disclosed embodiment is not limited to the above content, and various modifications can be made without departing from the gist and technical idea thereof.

In the above-described embodiment, the solder paste 33 is printed and heated in a reflow oven on both the pad portions 53 and 55 of the through hole 51 so that the entire flash plating layer 29 covers the pad portions 53 and 55 and the inner wall portion 57 . The solder plating layer 39 is formed in this way, but is not limited to this. 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 to cover the flash plating layer 29 of the pad portion 55 with the flash plating layer 29 of the inner wall portion 57 . The solder plating layer 39 is formed such that a part of the plating layer 29 (for example, half of the second surface 7B side) is formed. Furthermore, as shown in FIG. 18 , a jet stream of solder may be ejected from the launder to the first surface 7A side of the printed wiring board 7 on which the DIP component 47 is disposed on the second surface 7B side, and the solder may be filled into the through hole 51 . At the same time, the solder fillet 59 is formed, and the flash plating layer 29 covers the remaining portion of the pad portion 53 and the inner wall portion 57 (for example, half of the first surface 7A side).

In addition, in the case of this modification, in step S21 shown in FIG. 4 , the solder paste 33 is not printed on the pad portion 53 on the first surface 7A side, and in step S31 shown in FIG. 8 , The solder paste 33 only needs to be printed on the pad portion 55 on the second surface 7B side. According to this modification, the solder is difficult to reach the portion of the pad portion 55 on the side opposite to the side where the flow soldering is performed (the pad portion 55 on the side where the DIP component 47 is disposed) and the inner wall portion 57 (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., this description does not mean strictly. That is, these "perpendicular", "parallel" and "plane" are designed to allow manufacturing tolerances and errors, and refer to "substantially perpendicular", "substantially parallel" and "substantially plane".

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

In addition, in addition to the methods already described above, the methods of the above-described embodiments or modifications may be appropriately combined and utilized. Although not illustrated one by one, the above-described embodiments and modifications can be implemented with various modifications without departing from the gist of the embodiments.

1 electronic equipment

3 frame

5 Printed substrate

7 Printed wiring board (substrate)

9 substrate

11 through hole

12 copper layers

13 pad part

15 pad part

17 Inner wall part

29 flash coating

31 metal mask

33 solder paste

39 solder plating

41 metal mask

51 through hole

53 pad part

55 pad section

57 inner wall

61 through holes

63 pad part

65 pad part

67 inner wall part

Claims (6)

1. A method of manufacturing an electronic device, the electronic device being provided with a printed circuit board, the manufacturing method being characterized by having 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 Assemble the substrate with the components installed into the frame, The process of mounting the component to the substrate includes the following processes: mounting a surface mount component on the first surface of the substrate; Turn over the substrate and install other surface mounting components on the second surface opposite to the first surface; Mounting a DIP component with lead terminals inserted and fixed on the second surface of the substrate; flipping over the base plate and mounting the other DIP components on the first surface of the base plate, In the process of mounting the surface mount component on the first surface of the substrate and the process of mounting the other surface mount component on the second surface of the substrate, A process of forming a solder plating layer is performed to cover the flash plating layer formed on the pad portion on the first surface side, the pad portion on the second surface side, and the inner wall portion of the through hole into which the lead terminal is inserted. . 2. The manufacturing method of electronic equipment according to claim 1, characterized in that: The process of forming the solder plating includes the following processes: Printing solder paste on the flash layer using a metal mask; and The printed solder paste is heated and melted to cover the flash plating layer. 3. The manufacturing method of electronic equipment according to claim 2, characterized in that: The copper layer has: The pad portion is formed around an opening of the through hole formed in the substrate; and The inner wall portion is 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 a step of printing the solder paste on the flash plating layer of the pad portion, The step of covering the flash plating layer includes 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. 4. A method of manufacturing a printed circuit board, the manufacturing method is characterized by: having a step of mounting a component on a substrate on which a flash plating layer is formed to cover a predetermined portion of the copper layer, The process of mounting the component to the substrate includes: mounting a surface mount component on the first surface of the substrate; Turn over the substrate and install other surface mounting components on the second surface opposite to the first surface; Mounting a DIP component with lead terminals inserted and fixed on the second surface of the substrate; flipping over the base plate and mounting the other DIP components on the first surface of the base plate, In the process of mounting the surface mount component on the first surface of the substrate and the process of mounting the other surface mount component on the second surface of the substrate, A process of forming a solder plating layer is performed to cover the flash plating layer formed on the pad portion on the first surface side, the pad portion on the second surface side, and the inner wall portion of the through hole into which the lead terminal is inserted. . 5. The method for manufacturing a printed circuit board according to claim 4, characterized in that: The process of forming the solder plating includes the following processes: Printing solder paste on the flash layer using a metal mask; and The printed solder paste is heated and melted to cover the flash plating layer. 6. The method for manufacturing a printed circuit board according to claim 5, characterized in that: The copper layer has: The pad portion is formed around an opening of the through hole formed in the substrate; and The inner wall portion is 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 a step of printing the solder paste on the flash plating layer of the pad portion, The step of covering the flash plating layer includes 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.