JP2002111166A - Printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed board for soldering a mounting part excellently at low cost when the mounting part is fixed to. SOLUTION: A surrounding hole 4 is provided around a part inserting hole 3 for inserting an inserting part 10 of a mounting part. The surrounding hole 4 is formed as a through-hole, and a resist layer 6 is formed on a metallic layer 5 on the side of a solder flow face 1b. As a result, surface tension of a solder 20 on the solder flow face 1b to the metallic layer 5 can be improved. The solder 20 is prevented from flowing out of the surrounding hole 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board having a component insertion hole and subjected to a solder flow process.

[0002]

2. Description of the Related Art Conventionally, printed circuit boards have been widely used for mounting various electronic components. The printed board has a metal layer formed with a predetermined wiring pattern for connecting various electronic components on a board made of a non-conductive material.

[0003] A printed circuit board is generally subjected to a solder flow treatment in order to improve the "slipping" of the solder and increase the bonding strength. This solder flow process
This is a process of exposing one main surface of the printed circuit board to molten solder and applying solder in advance to a solder joint of the wiring pattern on this surface.

In the case where relatively large and heavy electronic components such as a transformer are mounted on such a printed circuit board, or when a support member or the like is mounted, for example,
There is a possibility that a sufficient joining effect may not be obtained only by soldering. Therefore, in such a case, a component insertion hole is formed in the printed circuit board, and an electronic component or a support member (hereinafter, these are collectively referred to as an attachment component) are inserted into the component insertion hole and then soldered. Is performed, the printed circuit board and the mounting component are joined.

Around these component insertion holes, a surface of the printed circuit board on which various electronic components are mounted (hereinafter, referred to as a component surface) and a surface on which solder flow processing is performed (hereinafter, referred to as a solder flow surface). ), A metal layer printed and formed in the same manner as the wiring pattern is formed. Then, after the attachment component or the like is inserted into the component insertion hole and the attachment component and the metal layer are soldered, the attachment component is joined to the printed circuit board.

At this time, in a conventional printed circuit board, a metal layer is generally formed also on the inner wall of the component insertion hole. As a result, the metal layer is formed continuously on the component surface, the solder flow surface, and the inner wall of the component insertion hole, whereby the strength is improved, and when a relatively large and heavy electronic component or a support member is attached. However, it is possible to prevent them from peeling off from the printed circuit board. The hole in which the metal layer is continuously formed on the component surface, the solder flow surface, and the inner wall of the hole as described above is generally called a through hole.

[0007]

By the way, as described above, the component insertion hole formed as a through-hole, as described above, is closed because the applied solder enters during the solder flow process. Problem.

Therefore, in order to prevent the component insertion hole from being closed by solder due to the solder flow process,
A method of performing masking using a mask material has been proposed. However, such a method of performing masking requires a process of applying a mask material around the component insertion hole, performing a solder flow process, and then removing the mask material. Therefore, not only does the work process become complicated, but also the mask material is thrown away, resulting in a problem of high cost.

In order to prevent the component insertion hole from being closed by solder due to the solder flow process, a technique called a so-called cut land has been proposed.
In the cut land method, a part of a metal layer formed around a component insertion hole on a solder flow surface is cut and formed. Thereby, since the surface tension of the solder can be reduced on the solder flow surface of the metal layer, the solder does not adhere to the solder flow surface during the solder flow process, and the component insertion hole is closed by the solder. Can be prevented.

However, when such a cut land method is used, if the component insertion hole is formed as a through hole, the solder enters the hole and is closed, so that the component insertion hole is formed as a through hole. Can not.
That is, since the metal layer in the component insertion hole cannot be continuously and integrally formed on the component surface and the solder flow surface, the strength of the metal layer is reduced. Therefore, when a relatively large and heavy electronic component or a supporting member is mounted, there is a problem that the metal layer is peeled off from the solder flow surface due to the stress, so that the mounting component is easily removed from the printed circuit board.

On the other hand, as a method for solving the above-mentioned problems when the masking method or the cut land method is used, a method of forming a plurality of peripheral holes as through holes around a component insertion hole has been proposed. I have. Thus, an example of a conventional printed circuit board using such a method will be described below with reference to FIG.

In a conventional printed circuit board, as shown in FIG. 16, a component insertion hole 101 is formed in a substrate 100 formed of a non-conductive material.
Are formed around the periphery. Metal layers 103 are formed on both main surfaces of the substrate 100 around the component insertion hole 101 and each of the peripheral holes 102 and on the inner wall of each of the peripheral holes 102. Also, the substrate 100
A resist layer 104 is formed on both main surfaces in a region where the metal layer 103 is not formed.

Although FIG. 16 shows only the vicinity of the component insertion hole 100 in the conventional printed circuit board, a predetermined wiring pattern is printed and formed on the printed circuit board in the same manner as the metal layer 103. Various electronic components are soldered to this wiring pattern. FIG. 16A is a schematic sectional view of a conventional printed circuit board. FIG. 16B is a plan view of the printed circuit board as viewed from the component surface 100a side of the board 100, and FIG.
6 (c) shows the solder flow surface 100 of the substrate 100.
It is a top view of the printed circuit board seen from b.

Here, the metal layer 103 has a cutout 103a formed in a part of the substrate 100 on the solder flow surface 100b side, and a so-called cut land method is employed. As a result, in the conventional printed circuit board, even when the solder flow process is performed, the solder does not adhere to the metal layer 103 on the solder flow surface 100b side, and the component insertion hole 101 is closed by the solder. It is prevented from being lost.

In a conventional printed circuit board, the component surface 100a, the solder flow surface 100b,
The metal layer 103 is formed continuously on the inner wall of each of the peripheral holes 102, whereby each of the peripheral holes 102 is formed as a through hole. Therefore, the metal layer 10
3 is improved, and even when a relatively large and heavy electronic component or a supporting member is soldered to the metal layer 103 formed on the solder flow surface 100b side, the metal layer 103 peels off. It is possible to prevent that.

However, as described above, the component insertion hole 1
In the case where a method of forming a plurality of peripheral holes 102 as through holes around 01 is adopted, the following problem occurs.

That is, when soldering is performed by inserting the insertion part 110 of the mounting component into the component insertion hole 101 of the above-described conventional printed circuit board, the function of the surface tension of the solder 120 in the peripheral hole 102 is reduced. FIG.
17A to 17D, the solder 120 flows out from the peripheral hole 102. Therefore, a proper fillet cannot be formed, and the bonding strength with the insertion portion 110 is deteriorated, so that there is a possibility that the mounting component may be removed from the printed circuit board. Further, there is a possibility that the solder 120 flowing out from the peripheral hole 102 may cause an electrical short circuit with another electronic component or the like.

Further, if the solder 120 leaks out, it is difficult to adjust the amount of the solder 120, thereby hindering the automation of the work. It is also difficult to remove or correct.

Accordingly, the present invention has been made to solve the above-mentioned problems and to provide a printed circuit board which can be soldered in a good condition and at low cost when fixing a mounting component to the printed circuit board. Aim.

[0020]

According to the present invention, there is provided a printed circuit board having a component insertion hole and a peripheral hole provided around the component insertion hole in order to solve the above-mentioned conventional problems. A metal layer formed on both the main surface of the substrate around the component insertion hole and the peripheral hole, an inner wall of the peripheral hole, and one main surface of the metal layer on a side to be a solder flow surface of the substrate A mask layer formed of a non-conductive material thereon.

In the printed circuit board according to the present invention configured as described above, since the metal layer formed on the solder flow surface side is covered with the mask layer, the function of the surface tension of the solder in the peripheral holes is improved. Can be done. Therefore, the solder does not flow out from the peripheral hole, and an appropriate fillet is formed near the component insertion hole,
The mounting parts can be soldered in a good condition.
In addition, since it is not necessary to peel off the formed mask layer, the operation steps can be simplified and cost reduction can be realized.

Preferably, the mask layer is formed so as to expose the metal layer outward in the vicinity of the end of the component insertion hole. Thereby, the function of the surface tension of the solder in the surrounding hole is further improved,
Solder outflow can be more reliably suppressed.

Further, it is desirable that the mask layer is formed of a resist material or a silk material. Thereby, the process of forming the mask layer is performed, for example, by forming a resist layer formed of a resist material to cover and insulate the wiring pattern on the printed circuit board, and forming characters indicating the mounting positions of various components on the printed circuit board. Therefore, it can be performed at the same time as the step of forming the silk layer formed of the silk material, and further, the operation steps can be simplified and the cost can be reduced.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. Hereinafter, a printed circuit board 1 as shown in FIG. 1 will be described as a configuration example of a printed circuit board to which the present invention is applied. The printed circuit board 1 is mounted with various electronic components and soldered, and is subjected to a solder flow process in order to improve “slipping” of the solder when performing the soldering. Therefore, hereinafter, the surface of the printed circuit board 1 on which various electronic components and the like are mounted is referred to as a component surface 1a, and the surface on which the solder flow processing is performed is referred to as a solder flow surface 1b.

As shown in the sectional view of FIG. 1, the printed circuit board 1 has a substantially oval component insertion hole 3 formed in a substrate 2 made of a non-conductive material. A plurality of peripheral holes 4 are formed around the component insertion hole 3. Further, a metal layer 5 is formed on both main surfaces of the substrate 2 around the component insertion hole 3 and each of the peripheral holes 4 and an inner wall of each of the peripheral holes 4.

Although FIG. 1 shows only the vicinity of the component insertion hole 3 in the printed circuit board 1, a predetermined wiring pattern is printed on the printed circuit board 1 in the same manner as the metal layer 5. Various electronic components are soldered to this wiring pattern. Also, FIG. 1 (a)
FIG. 1B is a schematic cross-sectional view of the printed circuit board 1, FIG. 1B is a plan view of the printed circuit board 1 as viewed from the component surface 1a side, and FIG. 1C is a view of the printed circuit board 1 as viewed from the solder flow surface 1b side. It is a top view.

The component insertion hole 3 is formed for mounting an electronic component or a support member (hereinafter, referred to as an attachment component) which is larger and heavier than various electronic components soldered to the wiring pattern. It is. That is, in the printed circuit board 1, as described later, the insertion portion of the mounting component is inserted into the component insertion hole 3, and the metal layer 5 in the vicinity of the component insertion hole 3 is soldered. This mounting component is supported and fixed to the substrate 2.

A plurality of peripheral holes 4 are formed around the component insertion hole 3. Then, the component surface 1a, the solder flow surface 1
The peripheral hole 4 is formed as a so-called through-hole because the metal layer 5 is continuously formed on the inner wall of each of the peripheral holes 4.

That is, in the printed circuit board 1, the plurality of peripheral holes 4 formed as through holes are provided around the component insertion hole 3, so that the metal layer 5 is formed between the component surface 1a and the solder flow surface 1b. It is formed integrally across. Thereby, the metal layer 5 has a sufficient strength, and is prevented from peeling off from the substrate 2. Therefore, even when the mounting component is a relatively large and heavy electronic component or a supporting member and a large stress is applied to the mounting portion, the mounting component and the substrate 2 can be reliably supported and fixed.

The peripheral holes 4 formed in the printed circuit board 1
The shape and number are not particularly limited, and may be a shape and number sufficient to secure the strength of the metal layer 5. Also, in FIG. 1, the metal layer 5 has a cutout portion 5a formed on a part of the solder flow surface 1b side, and a state where a so-called cut land method is adopted is illustrated.
In the printed circuit board 1, it is not always necessary to form the notch 5 a in the metal layer 5.

Incidentally, in the printed board 1, a resist layer 6 is formed on both main surfaces of the board 2. The resist layer 6 is formed of a resist material to cover and insulate a wiring pattern on the printed circuit board 1. However, the resist layer 6 exposes the wiring pattern to the outside at positions where various electronic components are to be soldered in the wiring pattern, and electrically connects the terminals of the electronic component that hide the wiring pattern at these positions by soldering. Connection is possible.

In the printed circuit board 1, the metal layer 5 formed near the end of the component insertion hole 3 is
1 without being covered by the resist layer 6 on the side
1B. As shown in FIG. 1B, the resist layer 6 is exposed to the outside and is formed on the solder flow surface 1b side by the resist layer 6. FIG.
Covered as shown.

In the printed circuit board 1, the metal layer 5 has the component side 1b.
By being exposed outward on the side, when the mounting component is soldered, the mounting component and the metal layer 5 can be fixed by soldering.

Further, since the metal layer 5 of the printed circuit board 1 is covered with the resist layer 6 on the solder flow surface 1b side, when the solder flow process is performed, the solder enters the component insertion hole 3 and Therefore, it is possible to prevent the component insertion hole 3 from being closed by solder.

Further, since the metal layer 5 of the printed circuit board 1 is covered with the resist layer 6 on the solder flow surface 1b side, the function of the surface tension of the solder in the peripheral hole 4 can be improved. As a result, FIG.
As shown in (a) to (d), when the insertion part 10 of the mounting component is inserted into the component insertion hole 3 and soldering is performed, the solder 20 does not flow out of the surrounding hole 4 and An appropriate fillet can be formed.

In the printed circuit board 1, the resist layer 6 may be formed so as to completely cover the metal layer 6 on the solder flow surface 1b side, but the end portion of the peripheral hole 4 on the solder flow surface 1b side. In the vicinity, it is desirable that the metal layer 5 be formed so as to be exposed to the outside. Thereby, the function of the surface tension of the solder 20 in the peripheral hole 4 can be further improved, and the outflow of the solder 20 can be more reliably suppressed.

Therefore, in the printed circuit board 1,
Cracks can be prevented from occurring in the solder 20 for fixing the metal layer 5 in the component insertion hole 3 and the insertion portion 10 of the attachment component, and durability and joining strength can be improved. For this reason, even when there is a possibility that a large stress may be applied to the joint, such as when the attachment component is a relatively large and heavy electronic component or a support member, the attachment component is attached to the printed circuit board 1. It can be securely attached to this.

Further, since the fillet of the solder 20 at the joint portion is smoothly connected to the insertion portion 10 of the mounting component and the metal layer 5, an increase in the electrical resistance value at the joint portion of the solder 20 can be prevented. There are advantages too. Generally, the component insertion hole 3 is provided for mounting a mounting component, and the solder 20 in the metal layer 5 near the component insertion hole 3 is formed for the purpose of fixing the mounting component. When the solder 20 is required to be electrically connected to the printed circuit board 1 as in the case of grounding, for example, it is possible to prevent an increase in the electric resistance value at the joint portion of the solder 20 and obtain a good connection. Securing the state is particularly effective.

Further, in the printed circuit board 1, since the solder 20 does not flow out from the peripheral hole 4,
At this junction, it is possible to prevent an electrical short circuit with another electronic component or the like. Also,
Since the solder 20 does not flow, it is easy to adjust the amount of the solder 20 required at this joint, and it is easy to automate the soldering operation using a robot or the like.

Even if the solder 20 flows out from the peripheral hole 4, the metal layer 5 in the vicinity of the component insertion hole 3 has a sufficient strength. It is easy to remove or correct by hand. Thereby, the yield can be improved. Also, by sucking out the solder 20,
Since the attachment parts can be easily removed, the attachment parts can be easily recycled.

As described above, the printed circuit board 1 can facilitate the automation of soldering, and can easily remove or correct the solder 20 even if the solder 20 leaks out. From
It is easy to improve the yield, improve the production efficiency and reduce the cost. In addition, since the solder 20 can be formed in a good state, the reliability at the joint can be improved.

In the above description, the shape of the component insertion hole 3 is an ellipse. However, the shape of the component insertion hole 3 is not particularly limited. It can be optional. Specifically, for example, as shown in FIG. 3, the component insertion hole 3 may be formed in a circular shape. FIG. 3A is a plan view of the printed circuit board 1 in this case as viewed from the component surface 1a side, and FIG.
Is a plan view of the printed circuit board 1 in this case, as viewed from the solder flow surface 1b side.

Next, an example in which a mounting component is mounted in the component insertion hole 3 on the printed circuit board 1 will be described with reference to FIG. Here, a case where a common choke coil 30 as shown in FIG. 4 and FIGS. 5 is a perspective view of the common choke coil 30, FIG. 6 is a front view of the common choke coil 30, FIG. 7 is a rear view of the common choke coil 30, and FIG. 8 is a common choke coil. 9 is a bottom view of the common choke coil 30, FIG. 10 is a right side view of the common choke coil 30, and FIG. 11 is a left side view of the common choke coil 30. . This common choke coil 30 has a height of about 2
cm to 5cm, and the width when viewed from the front is 1
cm, and the width when viewed from the side is about 1.5 cm.

In the common choke coil 30, as shown in FIG. 4, a first winding 32 made of a conductive material is wound around one side of a core material 31 formed in a substantially annular shape by a magnetic material. Both ends of the first winding 32 are led out in the same direction. On one side of the core material 31 opposite to the side on which the first winding 32 is wound, a second winding 33 made of a conductive material is formed in the same manner as the first winding 32. It is wound. This second winding 33 is also connected to the first
As in the case of the winding 32, both ends thereof are led out in the same direction.

When the common choke coil 30 configured as described above is mounted on the printed circuit board 1, for example, the first winding 32 derived from the core material 31 is used.
Is inserted into the component insertion hole 3 and the component surface 1 is inserted.
The first winding 32 is soldered to the metal layer 5 formed on the side a using the solder 20. Thereby, the common choke coil 30 is fixed to the printed circuit board 1.

Next, a specific method for manufacturing the above-described printed circuit board 1 will be described below.

When manufacturing the printed circuit board 1, first,
As shown in FIG. 12, a metal layer 5 is formed on both main surfaces of the substrate 2 by plating using a conductive material such as Cu. Next, after a mask is formed in a predetermined pattern using a resist material, etching is performed, and then the resist material is removed, thereby forming a metal layer 5 in a predetermined pattern as shown in FIG.

Next, as shown in FIG.
And a position where the peripheral hole 4 is to be formed. Next, a conductive material such as Cu is again used at a position where the peripheral hole 4 is to be formed, and a conductive material is filled into the hole thus formed by plating or the like. Next, the peripheral hole 4 is formed as a through hole as shown in FIG. 15 by re-drilling the hole filled with the conductive material with a diameter slightly smaller than the hole originally drilled. . That is, this allows the peripheral hole 4
The metal layer 5 is formed on the component surface 1a, the solder flow surface 1b, and the inner wall. Next, a resist layer 6 is formed in a predetermined pattern on both main surfaces of the substrate 2 so that the printed substrate 1 as shown in FIG.
Is completed.

In the printed circuit board 1, the resist layer 6
Function as a mask layer for covering the metal layer 5 on the solder flow surface 1b side. Such a resist layer 6 may be formed alone by performing a predetermined patterning. However, by forming the resist layer 6 with the same process using the same material as the resist layer for covering the wiring pattern, the working process can be simplified. Thus, cost reduction can be promoted. In the printed circuit board 1, the metal layer 5
On the solder flow surface 1b side as a mask layer,
It is not limited to using the resist layer 6,
For example, a silk layer formed of a silk material may be used to form characters indicating the mounting positions of various components on the printed circuit board 1, and the process may be performed simultaneously with the step of forming the silk layer. Also in this case, the resist layer 6
As in the case where is used, the working process can be simplified and the cost can be reduced.

[0050]

In the printed circuit board according to the present invention, since the metal layer formed on the solder flow surface side is covered with the mask layer, the surface tension of the solder does not greatly work in the peripheral holes. Accordingly, the solder does not flow out from the peripheral hole, an appropriate fillet is formed near the component insertion hole, and the mounting component can be soldered in a good state. In addition, since it is not necessary to peel off the formed mask layer, the operation steps can be simplified and cost reduction can be realized.

Therefore, the printed circuit board according to the present invention can secure a good bonding strength in the component insertion hole, and can securely attach a relatively large and heavy electronic component or a supporting member. Further, it is possible to prevent an electric short circuit from occurring.
Further, since the solder in the component insertion hole can be formed in a favorable state, it is easy to automate the operation and further reduce the cost. Furthermore,
Even if the solder flows out, since the metal layer has sufficient strength, it is easy to manually remove or correct the solder.

[Brief description of the drawings]

FIG. 1 is a view showing a printed circuit board as one configuration example of the present invention, and FIG. 1 (a) is a schematic sectional view of the printed circuit board;
(B) is a plan view of the printed circuit board as viewed from the component side, and (c) is a plan view of the printed circuit board as viewed from the solder flow side.

FIG. 2 is a schematic view showing a case where a mounting component is fixed to a component insertion hole in the printed circuit board by soldering.

3A and 3B are diagrams showing a printed circuit board as another configuration example of the present invention, wherein FIG. 3A is a plan view of the printed circuit board as viewed from the component side, and FIG. FIG.

FIG. 4 is a schematic diagram showing a case where a transformer as an example of a mounting component is fixed to a component insertion hole in the printed circuit board.

FIG. 5 is a perspective view showing an external configuration of a common choke coil.

FIG. 6 is a front view showing an external configuration of a common choke coil.

FIG. 7 is a rear view showing an external configuration of the common choke coil.

FIG. 8 is a plan view showing an external configuration of a common choke coil.

FIG. 9 is a bottom view showing an external configuration of the common choke coil.

FIG. 10 is a right side view illustrating an external configuration of a common choke coil.

FIG. 11 is a left side view showing an external configuration of a common choke coil.

FIG. 12 is a diagram for explaining the method for manufacturing the printed board, and is a schematic cross-sectional view showing a state where a metal layer is formed on the board.

FIG. 13 is a diagram for explaining a method of manufacturing the printed circuit board, and is a schematic cross-sectional view illustrating a state where a metal layer formed on the substrate is shaped into a predetermined shape.

FIG. 14 is a diagram for explaining a method of manufacturing the printed circuit board, and is a schematic cross-sectional view showing a state where a metal layer formed on the substrate is perforated at positions of a component insertion hole and a peripheral hole.

FIG. 15 is a diagram for explaining the method of manufacturing the printed circuit board, and is a schematic cross-sectional view showing a state where a metal layer in a peripheral hole is formed as a through hole.

FIG. 16 is a view showing a conventional printed circuit board, and FIG.
1 is a schematic cross-sectional view of a conventional printed circuit board, and FIG. 2B is a plan view of the conventional printed circuit board as viewed from the component side;
(C) is a plan view of a conventional printed circuit board viewed from a solder flow surface side.

FIG. 17 is a schematic view showing a case where a mounting component is fixed to a component insertion hole of a conventional printed circuit board by soldering.

[Explanation of symbols]

Reference Signs List 1 printed circuit board, 1a component surface, 1b solder flow surface, 2 substrate, 3 component insertion hole, 4 peripheral holes, 5 metal layer, 6 resist layer, 10 insertion part (for mounting parts), 2
0 Solder

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshinori Asayama 5-24-15 Minamidai, Nakano-ku, Tokyo Inside Calso Nick Kansei Corporation (72) Inventor Adult Sano 5-24-15 Minamidai, Nakano-ku, Tokyo Calso F term in Nick Kansei Corporation (reference) 5E319 AA02 AB01 AC12 CC23 CD57 GG03 5E336 AA01 AA04 BB01 BC34 CC07 CC08 CC51 EE03 GG06 5E338 AA02 BB02 BB04 BB13 BB16 BB25 BB75 CC01 CD33 EE51

Claims (3)

[Claims] 1. A board comprising: a component insertion hole; a peripheral hole provided around the component insertion hole; two main surfaces of the substrate around the component insertion hole and the peripheral hole; A printed circuit board comprising: a metal layer formed on an inner wall; and a mask layer formed of a non-conductive material on one principal surface of the metal layer on a side to be a solder flow surface of the substrate. 2. The printed circuit board according to claim 1, wherein the mask layer is formed near the end of the component insertion hole so as to expose the metal layer outward. 3. The printed circuit board according to claim 1, wherein the mask layer is formed of a resist material or a silk material.