JPH08274416A - Printed wiring board and its manufacture - Google Patents

Abstract

PURPOSE: To ensure reliability when a plurality of printed wiring boards are laminated and carried in packed state and to realize good handling property. CONSTITUTION: Land parts 2a, 3a of first and second wiring circuit patterns 2, 3 consisting of copper foil and projection parts 11a, 11b which are higher than through-hole parts 10a, 10b consisting of conductive paste 5 and a protection film 6 laminated thereon are formed at three or more places of each of both sides of an insulation board 1. The projection parts 11a, 11b can be formed by laminating solder resist layers 7a, 7b, symbol ink films 15, 19, conductive paste films 16, 20 and protection films 17, 21 on copper pad parts 14, 18 consisting of a copper foil. One kind among the symbol ink films 15, 19, the conductive paste films 16, 20 and the protection films 17, 21 is not necessarily laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board having through holes formed by connecting conductive circuit patterns respectively formed on different surfaces with a conductive paste, and a method for manufacturing the same. More specifically, a printed wiring board and a printed wiring board which are provided with protrusions that are higher than the height of the through holes on the printed wiring board to prevent the reliability from decreasing due to the decrease in the conductivity of the through holes and to improve the handleability are provided. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in various electronic devices such as a television receiver, a radio receiver, a cassette tape recorder, etc., a printed wiring board on which a predetermined wiring circuit is formed is frequently used for mounting a large number of electronic parts. Has been done.

As the density of wiring circuits has increased, printed wiring boards having wiring circuit patterns formed on both surfaces of an insulating substrate have come to be used. Further, in such a printed wiring board having a wiring circuit pattern on both sides of the insulating substrate, in order to achieve higher density of the wiring circuit, the lands of the wiring circuit patterns formed on both sides of the insulating substrate are opposed to each other. A through hole penetrating the insulating substrate is provided substantially at the center of a connecting portion called a portion, and a metal layer such as copper is formed by plating so as to be laminated from the inner wall surface of the through hole to part of the land portion. A connection hole called a conductive plated through hole is formed to electrically connect the wiring circuit patterns formed on different surfaces.

However, in the printed wiring board having the plated through holes as described above, there are disadvantages that the plating work is complicated and the manufacturing cost is increased due to the increased number of steps.

Therefore, in recent years, for the purpose of cost reduction, there is a printed wiring board in which a through hole which is a conductive connecting hole is formed by filling a through hole with a conductive paste such as silver paste and curing the paste. Proposed.

That is, instead of the plated film of the printed wiring board having the plated through hole, a conductive paste such as silver paste is laminated from the inner wall surface of the through hole to a part of the land portion, and the wiring circuit patterns on the upper and lower surfaces thereof are laminated. Are formed to electrically connect the wiring circuit patterns formed on different surfaces.

The printed wiring board as described above is manufactured, for example, as follows. First, a through hole is formed at a predetermined position of an insulating substrate having copper foils formed on both sides, and the copper foils on both sides of the insulating substrate are patterned to form a wiring circuit pattern having lands. Next, a solder resist layer is formed on the wiring circuit pattern formation surface except for the land portion, and symbol printing is performed. Further, the through hole is filled with a conductive paste, and the conductive paste is laminated on the inner wall surface of the through hole to a part of the land portion to form a through hole. Then, finally, a protective layer is formed on the wiring circuit pattern forming surface, and a protective film is laminated on the conductive paste on the land portion.

[0008]

By the way, when a printed wiring board as described above is delivered to a user, a plurality of printed wiring boards of the same kind are stacked and transported in a packed state.

However, at this time, the highest point in the printed wiring board is a through hole formed of a land portion 151 made of copper foil as shown in FIG. 16, a conductive paste 152 laminated thereon, and a protective film 153. The contact portion between the plurality of printed wiring boards is the through hole portion.

That is, external stress is likely to be applied to the through holes, and cracks 154 may occur in the conductive paste 152 in the through holes. In this way, cracks 15 are formed in the conductive paste 152.
When 4 occurs, the conduction between the lands 151 formed on both surfaces of the insulating substrate 155 is hindered, and the reliability of the printed wiring board is reduced.

Further, as described above, the conductive paste 152
Considering the possibility that cracks 154 may occur inside, the handleability of the printed wiring board is not very good,
The handling is complicated.

Therefore, the present invention has been proposed in view of the conventional state of the art, and even if a plurality of layers are stacked and transported in a packaged state, a land portion made of copper foil and a conductive paste laminated on the land portion are formed. , A stress is not applied to the through-hole portion made of the protective film, a crack is not generated in the conductive paste in the through-hole portion, reliability is ensured, and the handleability of the printed wiring board is good. It is intended to provide a manufacturing method.

[0013]

Means for Solving the Problems As a result of intensive studies made by the present inventors in order to achieve the above object, as a result, a land portion made of the above copper foil in a printed wiring board and a conductive layer laminated thereon are formed. By forming a protrusion that is higher than the height of the through-hole part made of a conductive paste and a protective film, even if a plurality of printed wiring boards are stacked, the contact part between the printed wiring boards becomes the above-mentioned protrusion and stress is applied to the through-hole part. Found that he would never join.

That is, according to the present invention, a through hole penetrating the insulating substrate is provided substantially at the center of the land portion of the wiring circuit pattern made of copper foil formed on both surfaces of the insulating substrate, and the inner wall surface of the through hole is provided. From the conductive paste laminated on a part of the land portion, in a printed wiring board having through holes formed by electrically connecting the wiring circuit patterns on the upper and lower surfaces thereof, on both surfaces of the insulating substrate,
It is characterized in that three or more protrusions higher than the height of the through hole are formed.

At this time, in the present invention, the protrusion may be higher than the height of the land portion formed of copper foil, the conductive paste laminated thereon, and the through hole portion formed of the protective film. The total laminated film thickness may be thicker than the total laminated film thickness of the through hole portion.

Therefore, the protrusions are formed by laminating a solder resist film, a symbol ink film, a conductive paste film, and a protective film on a copper pad part made of copper foil, and a copper pad part made of copper foil. A product in which a solder resist film, a symbol ink film, and a protective film are laminated on top, a product in which a solder resist film, a symbol ink film, and a conductive paste film are laminated on a copper pad portion made of copper foil, copper An example thereof is one in which a solder resist film, a conductive paste film, and a protective film are laminated and formed on a copper pad portion made of foil.

The protrusions may be formed anywhere other than the wiring circuit pattern forming portion of the printed wiring board. For example, the protrusions may be formed on a discarded substrate, and the wiring circuit in the finally remaining printed wiring board may be formed. It may be formed on a portion other than the pattern forming portion.

Further, the shape of the supporting portion may be any shape, and examples thereof include a plane circular shape and a plane rectangular shape.

As a method for manufacturing the above-mentioned printed wiring board, there is a manufacturing method according to a general method for manufacturing a printed wiring board. For example, it is provided at a predetermined position on an insulating substrate having copper foils formed on both sides. A step of forming a through hole, a step of patterning copper foil on both surfaces of the insulating substrate to form a wiring circuit pattern having a land portion, and a copper pad portion having a predetermined shape, and the wiring circuit pattern forming surface Forming a solder resist layer except on the land part, and forming a solder resist film on the copper pad part, and performing symbol printing on the wiring circuit pattern forming surface, A step of stacking a symbol ink film on the solder resist film, and filling the through hole with a conductive paste, and filling the conductive paste from the inner wall surface of the through hole to a part of the land portion. A step of forming a through hole by stacking and forming a conductive paste film also on the symbol ink film on the copper pad part, and forming a protective layer on the wiring circuit pattern forming surface, and also forming a copper pad part One having a step of forming a protrusion by laminating a protective film on the above conductive paste film is also exemplified.

The method for manufacturing the above printed wiring board is as follows.
It may be changed as appropriate according to the configuration of the protruding portion. When the protruding portion is formed by laminating a solder resist film, a symbol ink film, and a protective film on a copper pad portion made of copper foil,
In the step of filling the through holes with the conductive paste in the method for manufacturing a printed wiring board described above, the conductive paste film may not be laminated on the symbol ink film on the copper pad portion.

[0021]

In the printed wiring board of the present invention, the protrusions having a height higher than that of the through-hole portion are formed at three or more positions on both sides of the insulating substrate. The contact portion between the plates serves as the above-mentioned protruding portion, and stress is not applied to the through hole portion.

In the method for manufacturing a printed wiring board of the present invention, a copper pad portion having a predetermined shape is formed in the wiring circuit pattern forming step, and solder is also formed on the copper pad portion in the solder resist layer forming step. A layer of resist film is formed, and a symbol ink film is also formed on the solder resist film on the copper pad in the symbol printing process, and is also formed on the symbol ink film on the copper pad in the process of filling the conductive paste. Since the conductive paste film is laminated and formed in the protective layer forming step, the protective film is also laminated on the conductive paste film on the copper pad portion to form the protruding portion. Is fully integrated into the manufacturing process.

Further, the same applies when the protrusion forming step is changed according to the configuration of the protrusions. For example, the solder resist film, the symbol ink film, and the protective film are formed on the copper pad portion where the protrusions are made of copper foil. When the conductive paste film is laminated, the conductive paste film is laminated on the symbol ink film on the copper pad in the step of filling the conductive paste into the through hole in the method for manufacturing a printed wiring board. Since it suffices not to do so, the protrusion forming step is completely incorporated in the manufacturing process of the printed wiring board itself.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

Embodiment 1 In this embodiment, an example of a printed wiring board in which a solder resist film, a symbol ink film, a conductive paste film, and a protective film are laminated and formed on a copper pad portion whose protrusions are made of copper foil I will describe.

In the printed wiring board of this embodiment, as shown in FIG. 1, a first printed circuit pattern 2 having a plurality of lands 2a is formed on one surface of an insulating substrate 1, and a plurality of printed wiring boards are formed on the other surface. The second wired circuit pattern 3 having the land portion 3a is formed. However, here, only one land portion 2a, 3a is shown. In addition,
The first and second wiring circuit patterns 2 and 3 are each made of copper foil.

Further, the land portions 2a and 3 of the first and second wiring circuit patterns 2 and 3 on both surfaces of the insulating substrate 1 which are opposed to each other.
A conductive paste 5 made of copper or silver paste is laminated on the land 2a, 3a from the inner wall surface so as to penetrate the insulating substrate 1 substantially at the center of the first and second wiring circuit patterns 2. A through hole 4 for electrically connecting 3 is formed. Further, a protective film 6 made of epoxy resin or the like is formed on the conductive paste 5 laminated on the lands 2a and 3a to protect the conductive paste 5.

The insulating substrate 1 is exemplified by an insulating material such as paper or glass cloth impregnated with or coated with a phenol resin, a polyester resin, an epoxy resin, or the like.

Further, in the printed wiring board of this embodiment, as shown in FIGS. 1 and 2, a solder resist layer 7a for covering a portion of the wiring circuit pattern for mounting electronic parts and the like which does not require soldering. , 7b are formed on both surfaces of the insulating substrate 1, respectively.

Further, in the printed wiring board of this embodiment, the solder resist layers 7a and 7b on both surfaces of the insulating substrate 1 are used.
A symbol mark such as a character (not shown) is formed by symbol ink.

In the printed wiring board of the present embodiment, particularly, as shown in FIG. 3, the outer peripheral portion (so-called discarded substrate portion) of the finally remaining printed wiring board 9 shown by the broken line in the drawing of the printed wiring board 8 is shown. ) On both sides (only one side is shown in FIG. 3) formed by the land portions 2a and 3a as shown in FIG. 1 and the conductive paste 5 and the protective film 6 laminated thereon. Through hole part 10
Three projecting portions 11, 12, and 13 having a plane circular shape having a height higher than a and 10b are formed so as to be disposed on three sides of the discarded substrate.

At this time, the protrusions 11, 12, 13
As shown in FIG. 1 (only the protrusion 11 is shown in FIG. 1), the protrusions 11a and 11b are formed at positions facing each other with the insulating substrate 1 interposed therebetween. In the following, the first
The protrusion 11 arranged on the wiring circuit pattern 2 side is referred to as a protrusion 11a, and the protrusion 11 arranged on the second wiring circuit pattern 3 side is referred to as a protrusion 11b.

In this embodiment, the protrusion 11a is formed by sequentially laminating the solder resist layer 7a, the symbol ink film 15, the conductive paste film 16 and the protective film 17 on the copper pad 14 made of copper foil. And the protrusion 11
Similarly, b is formed by sequentially laminating the solder resist layer 7b, the symbol ink film 19, the conductive paste film 20, and the protective film 21 on the copper pad portion 18 made of copper foil. For example, when the protruding portion 11a is viewed from above, the copper pad portion 14 is completely covered with the solder resist layer 7a as shown in FIG. 2, and the conductive layer is covered with the symbol ink film 15 and the protective film 17 thereon. The paste film 16 will be formed.

That is, in the printed wiring board of the present embodiment, as shown in FIG.
Through hole portion 10a composed of conductive paste 5 and protective film 6, copper pad portion 14, solder resist layer 7
Comparing the heights of the protrusions 11a composed of a, the symbol ink film 15, the conductive paste film 16, and the protective film 17, the height of the solder resist layer 7a and the symbol ink film 15 is indicated by D ₁ in the drawing. There will be a difference.
This is the same even if the heights of the through hole portion 10b and the protruding portion 11b are compared.

Therefore, in the printed wiring board of the present embodiment, as shown in FIG. 4, two printed wiring boards 8a and 8a are provided.
When b is overlapped, these contact portions are not the through holes 10b ₁ and 10a ₂ but the protrusions 11b ₁ and 11a.
a _2, and the through holes 10a _1, 10b _1, 10
No stress is applied to a ₂ and 10 b ₂ . Moreover, since the protrusions 11, 12, and 13 are formed as three protrusions, the entire printed wiring board can be supported by the protrusions 11, 12, and 13.

Therefore, in the printed wiring board of this embodiment, the through hole portions 10a ₁ , 10b ₁ , 10 are formed.
No cracks are generated in the conductive pastes a ₂ and 10 b ₂ and the continuity of the first and second wiring circuit patterns 2 and 3 on both surfaces of the insulating substrate 1 is not hindered, and reliability is ensured. It Further, since the crack does not occur in the conductive paste, the handleability becomes good.

Although FIG. 4 shows an example in which two printed wiring boards are stacked, the same effect can be obtained by stacking more printed wiring boards. Further, in this embodiment, the example in which the protrusion is provided on the substrate part is described, but the protrusion may be formed anywhere other than the wiring circuit pattern forming part, and the final print remaining. You may form in a wiring board. Furthermore, in the present embodiment, the protrusions have a circular shape in a plane, but the protrusions may have, for example, a rectangular shape in a plane or a triangle as long as the protrusions can be in stable contact with each other.

Next, a method for manufacturing the printed wiring board of this embodiment will be described. That is, first, an insulating substrate 131 having copper foils 22 and 23 formed on both surfaces as shown in FIG. 5 is prepared. In this example, a paper phenol substrate having a thickness of 1.2 mm and a copper foil having a thickness of 30 μm formed on both sides was used.

Next, as shown in FIG. 6, the insulating substrate 131
A plurality of circular through holes 24, which are through holes that penetrate the copper foil 22, the insulating substrate 131, and the copper foil 23 and form through holes, are formed at predetermined positions. The through hole 24 is NC
It suffices to form it by a drill with (numerical) control, and the processing position and the hole diameter size are controlled with high accuracy. Here, the through holes 24 having a diameter of 0.5 mm are continuously formed at a pitch of 1.5 mm.

Subsequently, the copper foils 22 and 23 are patterned into a predetermined shape by the subtractive method, and as shown in FIG. 7, a circular land portion 2 serving as a connecting portion is provided at a predetermined position.
A first wiring circuit pattern 25 on which 5a is formed and a second wiring circuit pattern 26 on which a circular land portion 26a that is a connecting portion is formed at a predetermined position are formed. At this time, one opening 24a of the through hole 24 faces the center of the land portion 25a of the first wiring circuit pattern 25, and the other opening 24b faces the center of the land portion 26a of the second wiring circuit pattern 26. It is done like this. Here, the diameter of the land portions 25a and 26a is 1.2 mm.

At this time, in this embodiment,
Copper pad portions 27 and 28 facing each other are also formed on the three sides of the discarded substrate portion of the printed wiring board. However, only one place is shown here. The copper pad 2
7, 28 are formed as a plane circle having a diameter of 1.2 mm.

Next, as shown in FIG.
a and 26a and the first wiring circuit pattern 2
5. Solder resist layers 29a and 29b are formed on the portions of the second wiring circuit pattern 26 where solder adhesion should be avoided. At this time, solder resist layers 29a and 29b are also formed on the copper pad portions 27 and 28, respectively. In this embodiment, the solder resist layers 29a and 29b have a thickness of 20 μm.

Subsequently, symbol marks such as characters (not shown) are printed with symbol ink on the solder resist layers 29a and 29b on both surfaces of the insulating substrate 131. At this time, in the present embodiment, as shown in FIG. 9, the symbol ink is also printed on the positions corresponding to the copper pad portions 27, 28 on the solder resist layers 29a, 29b to form the symbol ink films 30, 31. Each is laminated.

Next, the through hole 24 is filled with a conductive paste such as silver paste or copper paste by screen printing. That is, as shown in FIG. 10, a screen 32 having an opening 32a is arranged on the first wiring circuit pattern 25 side in accordance with the position where the through hole 24 is formed. Then, the conductive paste 33 is placed on the screen 32, and the squeegee 34 is run in the direction indicated by an arrow M in the figure to scratch the conductive paste 33.

Then, the conductive paste 33 is extruded into the through hole 24 through the opening 32a and screen-printed, and the conductive paste 33 is laminated on a part of the land portion 25a of the first wiring circuit pattern 25. At the same time, it is filled in the through hole 24, wraps around, and is also laminated on a part of the land portion 26a of the second wiring circuit pattern 26.

In this embodiment, the land portion 25
The coating diameter of the conductive paste 33 on the surfaces a and 26a was 0.8 mm. Further, as the conductive paste 33, a copper paste TH1259 (trade name) manufactured by Tatsuta Electric Cable Co., Ltd. was used.

At this time, in this embodiment, the conductive paste 33 is filled in the through holes 24 and also printed on the symbol ink film 30 formed at the position corresponding to the copper pad portion 27. , Conductive paste film 3
5 is laminated. That is, the opening 32b is also formed at a position corresponding to the symbol ink film 30 on the screen 32, and screen printing is performed. The conductive paste film 35 was formed into a plane circular shape having a diameter of 0.5 mm.

Further, in this embodiment, the insulating substrate 1
Similarly, screen printing is also performed on the symbol ink film 31 formed at a position corresponding to the copper pad portion 28 disposed on the opposite side with the 31 sandwiched therebetween to form a conductive paste film 36 as shown in FIG. .

Subsequently, the through hole 2 as shown in FIG.
The conductive paste 33 filled in 4 is dried and hardened by heat. Then, the solvent or the like in the conductive paste 33 volatilizes and the conductive paste 33 shrinks and hardens, and the filled conductive paste 33 as shown in FIG. 11 electrically connects the lands 25a and 26a. Through holes 37, which are connection holes, are formed.

That is, the first and second wiring circuit patterns 25, 2 are formed on both surfaces of the insulating substrate 131 by the above steps.
6 is formed, and the first and second wiring circuit patterns 25,
A printed wiring board in which the land portions 25a and 26a, which are the connection portions of 26, are electrically connected by the through holes 37 is manufactured.

Next, as shown in FIG. 12, the conductive paste 33 in the through holes 37 is protected on the conductive paste 33 in the through holes 37 as a protective layer called an overcoat for protecting the conductive paste 33 from the heat from the solder. The film 38 is formed. In this embodiment, the protective film 38 is made of epoxy resin having a thickness of 20 μm.

In the present embodiment, the protective film 38 is formed, and at the same time, the conductive paste films 35 and 36 formed at the positions corresponding to the copper pad portions 27 and 28 are formed on the conductive paste films 35 and 36 in the same manner as the protective film 38. The protective films 39 and 40 are formed respectively, and the protrusions 41a and 41b are completed. The protective films 39 and 40 were formed in a plane circular shape having a diameter of 1.0 mm. Finally, press working is applied to finish the outer shape to obtain the printed wiring board of the present embodiment.

Therefore, in the printed wiring board manufactured by the method for manufacturing a printed wiring board of this embodiment, for example, the land portion having a thickness of 30 μm, the conductive paste having a thickness of 30 μm, and the protective film having a thickness of 20 μm are used. The height of the through hole is 80 μm, the copper pad is 30 μm thick, the solder resist layer is 20 μm thick, and the thickness is 15 μm.
m of the symbol ink film, the thickness of the conductive paste film of 30 μm, and the thickness of the protection film of 20 μm, the height of the projection is 115 μm. Equivalent to 35 μm
Will result in a difference of.

In the method of manufacturing the printed wiring board of this embodiment, the step of forming the protrusion is completely incorporated in the manufacturing process of the printed wiring board itself, which is a major change from the conventional method of manufacturing the printed wiring board. It is possible to manufacture the printed wiring board of the present embodiment without causing any adverse effect on the manufacturing cost, and its industrial value is very high.

Embodiment 2 In this embodiment, an example of a printed wiring board in which a solder resist film, a symbol ink film, and a protective film are laminated and formed on a copper pad portion whose protrusions are made of copper foil will be described.

The printed wiring board of this embodiment has substantially the same structure as the printed wiring board of the first embodiment. As shown in FIG. 13, a plurality of land portions 52a are formed on one surface of the insulating substrate 51. A first wired circuit pattern 52 having a plurality of land portions 53a is formed on the other surface.
The wiring circuit pattern 53 is formed.
However, here, only one land portion 52a, 53a is shown.

As in the printed wiring board according to the first embodiment, the land portions 52a, 53a facing each other are electrically connected by the conductive paste 55, and the first and second wiring circuit patterns 52,
Through holes 54 for electrically connecting 53 are formed. Further, a protective film 56 made of epoxy resin or the like is formed on the conductive paste 55 laminated on the land portions 52a and 53a to protect the conductive paste 55.

Also in the printed wiring board of the present embodiment, as shown in FIG. 13, solder resist layers 57a and 57b for covering the portions of the wiring circuit pattern for mounting electronic parts and the like that do not require soldering. Are formed on both surfaces of the insulating substrate 51, respectively.

Further, also in the printed wiring board of this embodiment, the solder resist layers 57a on both surfaces of the insulating substrate 51,
Symbol marks such as characters (not shown) are formed on the 57b with symbol ink.

Also in the printed wiring board of this embodiment, the land portions 5 as shown in FIG. 13 are formed on both sides of the discarded substrate portion, as in the printed wiring board of the first embodiment.
2a, 53a and conductive paste 5 laminated thereon
5, through hole portion 60 formed by the protective film 56
It is formed so that three projecting portions of a plane circular shape having a height higher than a and 60b are disposed on three sides of the discarded substrate.

At this time, in the printed wiring board of the present embodiment, the projection 61a arranged on the first wiring circuit pattern 52 side has the solder resist layer 57a and the symbol ink on the copper pad portion 64 made of copper foil. Film 65 and protective film 67
Are sequentially laminated. Similarly, the protrusion 61b arranged on the side of the second wiring circuit pattern 53 is also provided with the solder resist layer 57 on the copper pad 68 made of copper foil.
b, the symbol ink film 69 and the protective film 71 are sequentially laminated.

Therefore, when the printed wiring board of this embodiment is formed in the same manner as in Embodiment 1, for example, the height of the through hole portion 60a constituted by the land portion 52a, the conductive paste 55, and the protective film 56 becomes 80 μm. , Copper pad 6
4, solder resist layer 57a, symbol ink film 65,
The height of the protrusion 61a formed by the protective film 67 is 85.
μm, and comparing these, the solder resist layer 5
7a, a difference of 5 μm, which is the thickness of the symbol ink film 65 minus the thickness of the conductive paste 55, is generated.

That is, also in the printed wiring board of the present embodiment, as in the printed wiring board of the first embodiment, these contact portions when a plurality of printed wiring boards are stacked are not the through holes but the protrusions. No stress is applied to the through hole. Further, since the three protruding portions are formed as the protruding portions, it is possible to support the entire printed wiring board by the protruding portions.

As a result, even in the printed wiring board of this embodiment, no cracks are generated in the conductive paste in the through holes, and the first and second surfaces of the insulating substrate are both formed.
The reliability is assured without the conduction of the wiring circuit pattern being disturbed. Further, since the crack does not occur in the conductive paste, the handleability becomes good.

Also in this embodiment, the protrusions may be formed anywhere other than the wiring circuit pattern forming portion, or may be formed in the finally remaining printed wiring board. Furthermore, also in the present embodiment, the protrusions may have any shape as long as the protrusions can contact each other in a stable manner, and the protrusions may have, for example, a rectangular shape in a plane or a triangle.

In order to manufacture the printed wiring board of this embodiment, the manufacturing method described in Embodiment 1 may be used, and the conductive paste may be formed in the through holes in the manufacturing method described in Embodiment 1. In the step of filling, the conductive paste film may not be laminated on the symbol ink film on the copper pad portion.

Also, in the method of manufacturing a printed wiring board of this embodiment, the step of forming the protrusion is completely incorporated in the manufacturing process of the printed wiring board itself, which greatly changes the conventional method of manufacturing a printed wiring board. It is possible to manufacture the printed wiring board of the present embodiment without causing any adverse effect on the manufacturing cost, and its industrial value is very high.

Embodiment 3 In this embodiment, an example of a printed wiring board in which a solder resist film, a symbol ink film, and a conductive paste film are laminated and formed on a copper pad portion whose protrusions are made of copper foil will be described.

The printed wiring board according to the present embodiment has substantially the same structure as the printed wiring board according to the first embodiment. As shown in FIG. 14, a plurality of land portions 72a are formed on one surface of the insulating substrate 141. Is formed, and the second wiring circuit pattern 73 having a plurality of lands 73a is formed on the other surface. However, here, one land portion 72a, 73a
Only shall be indicated.

As in the printed wiring board of the first embodiment, the land portions 72a and 73a facing each other are electrically connected by the conductive paste 75, and the first and second wiring circuit patterns 72,
Through holes 74 are formed to electrically connect 73 to each other. Further, a protective film 76 made of epoxy resin or the like is formed on the conductive paste 75 laminated on the land portions 72a and 73a to protect the conductive paste 75.

Also in the printed wiring board of the present embodiment, as shown in FIG. 14, solder resist layers 77a, 77b for covering the portions of the wiring circuit pattern for mounting electronic parts and the like which do not require soldering. Are formed on both surfaces of the insulating substrate 141, respectively.

Further, also in the printed wiring board of this embodiment, the solder resist layers 77 on both surfaces of the insulating substrate 141 are used.
Symbol marks such as characters (not shown) are formed on the a and 77b with symbol ink.

Also, in the printed wiring board of this embodiment, as in the printed wiring board of the first embodiment, land portions 7 as shown in FIG.
2a, 73a and conductive paste 7 laminated thereon
5. Through hole portion 80 formed by the protective film 76
It is formed so that three protrusions of a plane circular shape having a height higher than a and 80b are disposed on three sides of the discarded substrate.

At this time, in the printed wiring board of this embodiment, the projection 91a arranged on the first wiring circuit pattern 72 side has the solder resist layer 77a and the symbol ink on the copper pad portion 84 made of copper foil. The film 85 and the conductive paste film 86 are sequentially laminated and formed. Protrusions 91 arranged on one side of the second wiring circuit pattern 73
Similarly, b is also formed by sequentially stacking a solder resist layer 77b, a symbol ink film 89, and a conductive paste film 90 on a copper pad portion 88 made of a copper foil.

Therefore, when the printed wiring board of this embodiment is formed in the same manner as in Embodiment 1, for example, the height of the through hole portion 80a constituted by the land portion 72a, the conductive paste 75, and the protective film 76 becomes 80 μm. , Copper pad 8
4, solder resist layer 77a, symbol ink film 85,
The height of the projection 91a formed by the conductive paste film 86 is 95 μm. By comparing these, the thickness of the solder resist layer 77a and the symbol ink film 85 minus the thickness of the protective film 86 is 15 μm. There will be a difference.

That is, also in the printed wiring board of the present embodiment, like the printed wiring board of the first embodiment, these contact portions when a plurality of printed wiring boards are stacked are not the through holes but the projections. No stress is applied to the through hole. Further, since the three protruding portions are formed as the protruding portions, it is possible to support the entire printed wiring board by the protruding portions.

As a result, even in the printed wiring board of this embodiment, no cracks are generated in the conductive paste in the through holes, and the first and second surfaces on both sides of the insulating substrate are prevented.
The reliability is assured without the conduction of the wiring circuit pattern being disturbed. Further, since the crack does not occur in the conductive paste, the handleability becomes good.

In the present embodiment as well, the protrusion may be formed anywhere as long as it is a portion other than the wiring circuit pattern forming portion, or may be formed in the finally remaining printed wiring board. Furthermore, also in the present embodiment, the protrusions may have any shape as long as the protrusions can contact each other in a stable manner, and the protrusions may have, for example, a rectangular shape in a plane or a triangle.

In order to manufacture the above-mentioned printed wiring board of the present embodiment, the manufacturing method described in the first embodiment may be performed. On the wiring circuit pattern forming surface in the manufacturing method described in the first embodiment. In the step of forming the protective layer, the protective film may not be laminated on the conductive paste film on the copper pad portion.

Also in the method of manufacturing a printed wiring board of this embodiment, the step of forming the protrusion is completely incorporated into the manufacturing process of the printed wiring board itself, which is a major change from the conventional method of manufacturing a printed wiring board. It is possible to manufacture the printed wiring board of the present embodiment without causing any adverse effect on the manufacturing cost, and its industrial value is very high.

Embodiment 4 In this embodiment, an example of a printed wiring board in which a solder resist film, a conductive paste film and a protective film are laminated and formed on a copper pad portion whose protrusions are made of copper foil will be described.

The printed wiring board of this embodiment has substantially the same structure as the printed wiring board of Embodiment 1. As shown in FIG. 15, a plurality of land portions 102a are formed on one surface of the insulating substrate 101. First wired circuit pattern 10 having
2 is formed, and the second wiring circuit pattern 103 having a plurality of lands 103a is formed on the other surface. However, here, one land portion 102
Only a and 103a are shown.

Further, similar to the printed wiring board of the first embodiment, the land portions 102a and 103a facing each other are electrically connected by the conductive paste 105, and the first and second wiring circuit patterns 102 and 103 are electrically connected. Through hole 10
4 are formed. Further, the land portion 102a,
On the conductive paste 105 laminated on 103a, a protective film 10 made of an epoxy resin or the like for protecting the conductive paste 105 is formed.
6 is formed.

Also in the printed wiring board of the present embodiment, as shown in FIG. 15, solder resist layers 107a and 107b for covering the portions of the wiring circuit pattern for mounting electronic parts etc. that do not require soldering. Is an insulating substrate 101
Are formed on both sides of each.

Further, also in the printed wiring board of this embodiment, the solder resist layers 107 on both surfaces of the insulating substrate 101 are used.
Symbol marks such as characters (not shown) are formed on the a and 107b with symbol ink.

Also in the printed wiring board of the present embodiment, as in the printed wiring board of the first embodiment, the land portion 1 as shown in FIG.
02a, 103a, conductive paste 105 laminated thereon, and protective film 106 are formed on the three sides of the substrate. Is formed.

At this time, in the printed wiring board of the present embodiment, the projections 111a arranged on the first wiring circuit pattern 102 side are electrically conductive with the solder resist layer 107a on the copper pad portion 114 made of copper foil. The paste film 116 and the protective film 117 are sequentially laminated. Similarly, the protrusion 111b arranged on the side of the second wiring circuit pattern 103 is also one in which the solder resist layer 107b, the conductive paste film 120, and the protective film 121 are sequentially laminated on the copper pad 118 made of copper foil. It is said that.

Therefore, when the printed wiring board of this embodiment is formed in the same manner as in Embodiment 1, for example, the land portion 102a,
The height of the through-hole portion 110a formed by the conductive paste 105 and the protective film 106 is 80 μm, and the projection 1 formed by the copper pad portion 114, the solder resist layer 107a, the conductive paste film 116, and the protective film 117.
The height of 11a is 100 μm, and when these are compared, 20 μ, which corresponds to the thickness of the solder resist layer 107a, is obtained.
There will be a difference of m.

That is, also in the printed wiring board of the present embodiment, like the printed wiring board of the first embodiment, these contact portions when a plurality of printed wiring boards are stacked are not the through holes but the projections. No stress is applied to the through hole. Further, since the three protruding portions are formed as the protruding portions, it is possible to support the entire printed wiring board by the protruding portions.

As a result, even in the printed wiring board of this example, no cracks were generated in the conductive paste in the through holes, and the first and second surfaces of the insulating substrate were both formed.
The reliability is assured without the conduction of the wiring circuit pattern being disturbed. Further, since the crack does not occur in the conductive paste, the handleability becomes good.

Also in this embodiment, the protrusion may be formed anywhere other than the portion where the wiring circuit pattern is formed, or may be formed in the finally remaining printed wiring board. Furthermore, also in the present embodiment, the protrusions may have any shape as long as the protrusions can contact each other in a stable manner, and the protrusions may have, for example, a rectangular shape in a plane or a triangle.

To manufacture the printed wiring board of the present embodiment, the manufacturing method described in the first embodiment may be carried out, and the step of printing the symbol mark in the manufacturing method described in the first embodiment. In the above, the symbol ink film may not be laminated on the solder resist film on the copper pad portion.

Also in the printed wiring board manufacturing method of this embodiment, the projection forming step is completely incorporated into the manufacturing step of the printed wiring board itself, which greatly changes the conventional printed wiring board manufacturing method. It is possible to manufacture the printed wiring board of the present embodiment without causing any adverse effect on the manufacturing cost, and its industrial value is very high.

[0094]

As is apparent from the above description, in the printed wiring board of the present invention, the protrusions having a height higher than that of the through hole are formed at three or more places on each side of the insulating substrate. Even if a plurality of printed wiring boards are laminated, the contact portions between the printed wiring boards serve as the protrusions, so that no stress is applied to the through holes. Further, since the protrusions are formed at three or more places, the entire printed wiring board can be supported by the protrusions.

Therefore, in the printed wiring board of the present invention, no cracks are generated in the conductive paste in the through holes, and the conduction of the first and second wiring circuit patterns on both surfaces of the insulating substrate is prevented. The reliability is ensured without being affected. Further, since the crack does not occur in the conductive paste, the handleability becomes good.

In the method for manufacturing a printed wiring board according to the present invention, a copper pad portion having a predetermined shape is formed in the wiring circuit pattern forming step, and solder is also formed on the copper pad portion in the solder resist layer forming step. A layer of resist film is formed, and a symbol ink film is also formed on the solder resist film on the copper pad in the symbol printing process, and is also formed on the symbol ink film on the copper pad in the process of filling the conductive paste. Since the conductive paste film is laminated and formed in the protective layer forming step, the protective film is also laminated on the conductive paste film on the copper pad portion to form the protruding portion. Is fully integrated into the manufacturing process. Therefore, the printed wiring board of the present invention can be manufactured without significantly changing the conventional method for manufacturing a printed wiring board, the manufacturing cost is little affected, and the industrial value thereof is very high.

Further, the same applies when the protrusion forming step is changed according to the configuration of the protrusions. For example, the solder resist film, the symbol ink film, and the protective film are formed on the copper pad portion where the protrusions are made of copper foil. When the conductive paste film is laminated, the conductive paste film is laminated on the symbol ink film on the copper pad in the step of filling the conductive paste into the through hole in the method for manufacturing a printed wiring board. Since it is not necessary to do so, the protrusion forming step is completely incorporated into the manufacturing process of the printed wiring board itself, and it is possible to manufacture without significantly changing the conventional manufacturing method of the printed wiring board. However, it has little impact on the manufacturing cost and its industrial value is very high.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an essential part showing an embodiment of a printed wiring board to which the present invention is applied.

FIG. 2 is a main part schematic plan view showing an embodiment of a printed wiring board to which the present invention is applied.

FIG. 3 is a plan view schematically showing an embodiment of a printed wiring board to which the present invention is applied.

FIG. 4 is a schematic cross-sectional view of an essential part showing a state in which two printed wiring boards to which the present invention is applied are stacked in an embodiment.

FIG. 5 shows an embodiment of a method for manufacturing a printed wiring board to which the present invention is applied, in order of steps, and is a schematic cross-sectional view of a main part showing a step of preparing an insulating substrate.

FIG. 6 shows one embodiment of a method for manufacturing a printed wiring board to which the present invention is applied in the order of steps, and is a schematic cross-sectional view of a main part showing a step of forming a through hole.

FIG. 7 shows an embodiment of a method for manufacturing a printed wiring board to which the present invention is applied in the order of steps, and is a schematic cross-sectional view of a main part showing a step of forming a wiring circuit pattern.

FIG. 8 shows an embodiment of a method for manufacturing a printed wiring board to which the present invention is applied, in order of steps, and is a schematic cross-sectional view of a main part showing a step of forming a solder resist layer.

FIG. 9 is a schematic cross-sectional view of a main part showing an embodiment of the method for manufacturing a printed wiring board to which the present invention is applied, in the order of steps, and showing a step of printing with symbol ink.

FIG. 10 shows one embodiment of a method for manufacturing a printed wiring board to which the present invention is applied, in order of steps, and is a schematic sectional view of a main part showing a step of screen-printing a conductive paste.

FIG. 11 is a schematic cross-sectional view of a main part showing an embodiment of the method for manufacturing a printed wiring board to which the present invention is applied, in the order of steps, and showing a step of drying and curing the conductive paste.

FIG. 12 shows one embodiment of a method for manufacturing a printed wiring board to which the present invention is applied, in order of steps, and is a schematic cross-sectional view of a main part showing a step of forming a protective film.

FIG. 13 is a schematic sectional view of an essential part showing another embodiment of the printed wiring board to which the present invention is applied.

FIG. 14 is a schematic cross-sectional view of a main part showing still another embodiment of a printed wiring board to which the present invention is applied.

FIG. 15 is a schematic cross-sectional view of a main part showing still another embodiment of a printed wiring board to which the present invention is applied.

FIG. 16 is a schematic cross-sectional view of an essential part showing a state in which a plurality of conventional printed wiring boards are stacked.

[Explanation of symbols]

1, 51, 101, 131, 141 Insulating substrate 2, 25, 52, 72, 102 First wiring circuit pattern 2a, 3a, 25a, 26a, 52a, 53a, 72
a, 73a, 102a, 103a Land portion 3, 26, 53, 73, 103 Second wiring circuit pattern 4, 37, 54, 74, 104 Through hole 5, 33, 55, 75, 105 Conductive paste 6, 17 , 21, 38, 39, 40, 56, 67, 7
1, 76, 106, 117, 121 Protective film 7a, 7b, 29a, 29b, 57a, 57b, 77
a, 77b, 107a, 107b Solder resist layers 10a, 10b, 60a, 60b, 80a, 80b, 1
10a, 110b Through hole part 11, 11a, 11b, 12, 13, 41a, 41b,
61a, 61b, 91a, 91b, 111a, 111b
Protrusions 14, 18, 27, 28, 64, 68, 84, 88, 1
14,118 Copper pad part 15,19,30,31,65,69,85,89 Symbol ink film 16,20,35,36,86,90,116,120
Conductive paste film 22,23 Copper foil 24 Through hole

Claims (9)

[Claims] 1. A through hole penetrating the insulating substrate is provided substantially at the center of a land portion of a wiring circuit pattern made of copper foil formed on both surfaces of the insulating substrate, and the inner wall surface of the through hole extends from the inner wall surface of the land portion. In a printed wiring board that has through holes formed by electrically connecting the wiring circuit patterns on the upper and lower surfaces of the conductive paste that is partially laminated, the height of the through holes on each side of the insulating substrate. A printed wiring board having three or more protrusions that are higher than the height. 2. A solder resist film, a symbol ink film, a conductive paste film, and a protective film are laminated and formed on a copper pad portion whose protrusion is made of copper foil. Printed wiring board. 3. The printed wiring board according to claim 1, wherein a solder resist film, a symbol ink film, and a protective film are laminated and formed on a copper pad portion whose protrusion is made of copper foil. 4. The printed wiring according to claim 1, wherein the protrusion is formed by laminating a solder resist film, a symbol ink film, and a conductive paste film on a copper pad part made of copper foil. Board. 5. The printed wiring board according to claim 1, wherein a solder resist film, a conductive paste film, and a protective film are laminated and formed on a copper pad portion whose protrusion is made of copper foil. . 6. A step of forming through-holes at predetermined positions of an insulating substrate having copper foils formed on both sides, and patterning the copper foils on both sides of the insulating substrate to form a wiring circuit pattern having lands. A step of forming a copper pad portion having a predetermined shape, and a step of forming a solder resist layer on the wiring circuit pattern formation surface except on the land portion and forming a solder resist film on the copper pad portion And, perform symbol printing on the wiring circuit pattern formation surface,
A step of stacking a symbol ink film on the solder resist film on the copper pad part, and filling the through hole with a conductive paste, and stacking the conductive paste from the inner wall surface of the through hole to a part of the land part. To form a through hole and to form a conductive paste film on the symbol ink film on the copper pad part, and to form a protective layer on the wiring circuit pattern forming surface, and also on the copper pad part. 2. A method for manufacturing a printed wiring board, comprising the step of forming a protrusion by forming a protective film on the conductive paste film. 7. A step of forming through holes at predetermined positions of an insulating substrate having copper foils formed on both sides, and patterning the copper foils on both sides of the insulating substrate to form a wiring circuit pattern having lands. A step of forming a copper pad portion having a predetermined shape, and a step of forming a solder resist layer on the wiring circuit pattern formation surface except on the land portion and forming a solder resist film on the copper pad portion And, perform symbol printing on the wiring circuit pattern formation surface,
A step of stacking a symbol ink film on the solder resist film on the copper pad part, and filling the through hole with a conductive paste, and stacking the conductive paste from the inner wall surface of the through hole to a part of the land part. And the step of forming a through hole, and the step of forming a protective layer on the wiring circuit pattern formation surface and forming a protective film on the symbol ink film on the copper pad to form a protrusion. A method of manufacturing a printed wiring board having the same. 8. A step of forming through holes at predetermined positions on an insulating substrate having copper foils formed on both sides, and patterning the copper foils on both sides of the insulating substrate to form a wiring circuit pattern having lands. A step of forming a copper pad portion having a predetermined shape, and a step of forming a solder resist layer on the wiring circuit pattern formation surface except for the land portion, and forming a solder resist film on the copper pad portion And, perform symbol printing on the wiring circuit pattern formation surface,
A step of stacking a symbol ink film on the solder resist film on the copper pad part, and filling the through hole with a conductive paste, and stacking the conductive paste from the inner wall surface of the through hole to a part of the land part. And forming a through hole, and forming a protrusion by forming a conductive paste film on the symbol ink film on the copper pad, and forming a protective layer on the wiring circuit pattern formation surface. A method for manufacturing a printed wiring board having steps. 9. A step of forming a through hole at a predetermined position of an insulating substrate having copper foils formed on both sides, and patterning the copper foils on both sides of the insulating substrate to form a wiring circuit pattern having lands. A step of forming a copper pad portion having a predetermined shape, and a step of forming a solder resist layer on the wiring circuit pattern formation surface except on the land portion and forming a solder resist film on the copper pad portion And a step of performing symbol printing on the wiring circuit pattern forming surface, filling the through hole with a conductive paste, and laminating the conductive paste from the inner wall surface of the through hole to a part of the land portion to form the through hole. And forming a conductive paste film on the solder resist film on the copper pad portion, and forming a protective layer on the wiring circuit pattern forming surface, and Method for manufacturing a printed wiring board in the conductive paste films on de portion having a step of forming a projecting portion by laminating a protective film.