JPH0556876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a printed wiring board for through-holes and a method for manufacturing the same.

[Background technology]

Through-hole printed wiring boards have through-holes for mounting components and connecting electrical circuits on the front and back sides of the board. Printed wiring boards in which through-holes are formed in this way have conventionally been manufactured as shown in FIGS. 4a to 4c.

That is, as shown in FIG. 4a, a metal plate 1 made of aluminum, iron, etc. is prepared, and holes 2 for through holes are formed in this metal plate 1. Electrodeposition coating is applied to the metal plate 1, and the entire surface of the metal plate 1 including the inner wall surface of the hole 2 is covered with an electrodeposition paint layer 4, as shown in FIG. 4b. Thereafter, as shown in FIG. 4c, a conductor layer 6 is formed on the electrodeposition paint layer in the hole 2 and on both surfaces of the electrodeposition paint layer by a plating method such as a full additive method or a semiadditive method, and the conductor layer 6 is And a printed wiring board in which through holes 7 were formed was obtained.

In the printed wiring board for through-holes obtained as described above, the insulating layer 10 that insulates between the metal plate 1 and the conductor layer 6 was composed only of the electrodeposition paint layer 4. If even a single pinhole appeared in the insulation, it would immediately become an insulation failure. In addition, since the electrodeposition paint has fluidity during curing, the electrodeposition paint layer 4 tends to become thinner at the corner portion (edge portion) 71 of the through hole 7, making it difficult to ensure insulation at that portion. I was getting used to it. As described above, conventional printed wiring boards have low insulation reliability, have a large number of defective products, and cannot be manufactured with a high yield.

In addition, as another conventional technology, Japanese Patent Application Laid-Open No. 54-145966
There is a method disclosed in the publication No. In this known technique, an anodic oxide film is formed on the surface of the metal plate and the inner wall surface of the through hole, and then an electrodeposition paint layer similar to that described above is formed. According to this prior art, by providing an insulating layer consisting of two layers, an anodic oxide film and an electrodeposition paint layer, it is possible to exhibit good insulation properties.

However, the above method has a problem in that cracks occur in the anodic oxide film at the corners of the through holes when a thermal shock is applied to the printed wiring board. This is because the anodic oxide film has the disadvantage of being brittle, so cracks occur when subjected to thermal shock, and when cracks occur in the anodic oxide film, cracks also occur in the thin electrodeposited paint layer that covers it. As a result, the insulation properties will deteriorate.

Furthermore, as another conventional technology, JP-A-51-
There is a method disclosed in Publication No. 22064. According to this known technique, the oxide film can be sealed by covering the surface of the oxide film with an insulating resin as an insulating layer, and as a result, the insulation properties are improved.

However, with this method, the insulating resin layer becomes thinner at the corners of the through holes, so as above,
When thermal shock is applied, cracks occur at the corners of the through-holes, and the insulating properties of the corners covered only with a thin insulating resin layer deteriorate. Furthermore, when the surface of the insulating resin is roughened in order to form electric circuits by plating, there is also the problem that pinholes are generated at the corners of the through-holes where the insulating resin layer is thin, as described above. This is because the insulating resin layer is usually formed by applying liquid insulating resin, so the corners of the through-hole are inevitably thinner than other parts due to the surface tension of the liquid. It is.

[Purpose of the invention]

In view of the above circumstances, the first invention aims to provide a printed wiring board that has high insulation reliability and can be manufactured at a high yield, and the second invention aims to provide a printed wiring board according to the first invention that can be manufactured at a high yield. The purpose is to provide a manufacturing method for obtaining good results.

[Disclosure of the invention]

In order to achieve the above object, a first invention provides a metal plate in which at least a portion of a metal plate in which a through hole is formed is covered with an insulating layer, and a conductive layer is formed on the insulating layer. In the printed wiring board, the insulating layer includes an insulating chemical conversion coating layer that covers the surface of the metal plate and the inner wall of the through hole, and an electrodeposition coating layer that covers the chemical conversion coating layer;
The gist of the invention is a printed wiring board characterized by being composed of three layers: this electrodeposition paint layer and an insulating resin layer made of an adhesive that covers the electrodeposition paint layer. Further, a second invention provides a printed wiring board in which at least a portion of a metal plate in which a through hole is formed, on which a conductive layer is formed, is covered with an insulating layer, and a conductive layer is formed on the insulating layer. A manufacturing method, which includes the following a to g.
The gist is a method for manufacturing printed wiring boards characterized by including the following steps.

a Step of forming holes for through holes in the metal plate b Step of forming a chemical conversion coating layer on at least the portion where the conductor layer is formed on the metal plate and the through hole portion c An electrodeposition paint layer covering the chemical conversion coating layer Step d: Applying an adhesive on the electrodeposited paint layer and the through holes on one side of the metal plate Step e: Suction is applied from the opposite side of the metal plate, and the adhesive layer is left on the inner wall surface of the through hole hole. step f of removing the adhesive from the opposite side of the metal plate in the same manner as steps d and e above, and step g of forming an insulating layer with adhesive on the insulating layer. Step of Forming a Conductor Layer Below, the first and second inventions will be explained in detail with reference to drawings showing one embodiment of each of the inventions.

First, the first invention will be explained.

FIG. 1 shows an embodiment of a printed wiring board according to the first invention. As shown in the figure,
This printed wiring board includes a metal plate 1 in which holes 2 for through holes are formed. This metal plate 1
The entire surface including the inner wall surface of the hole 2 is covered with an insulating layer 10. A conductor layer 6 (electrical path 6a) is formed on the insulating layer 10 in the hole 2 and on the insulating layer 10 on both sides. The insulating layer 10 is composed of an insulating chemical conversion coating layer 3 covering the metal plate 1, an electrodeposition coating layer 4 covering the chemical conversion coating layer 3, and an insulating resin layer 5 covering the electrodeposition coating layer 4. ing.

As described above, in this printed wiring board, the insulating layer 10 between the metal plate 1 and the conductor layer 6 has three insulating chemical conversion coating layers 3, an electrodeposition paint layer 4, and an insulating resin layer 5. It is composed of layers. Therefore,
Even if a pinhole occurs in one of the layers, insulation can be maintained in the other layers. Therefore, insulation reliability is high and the number of defective products is reduced.
It can be manufactured with good yield.

Moreover, although the insulating chemical conversion coating layer 3 is formed by chemical conversion treatment, it is also formed with a uniform thickness at the corner portion (edge portion) 71 of the through hole 7, so that the layer 3 is electrodeposited at the corner portion 71. Even if the amount of the paint in the paint layer 4 and the resin in the insulating resin layer 5 is reduced, the insulation distance between the metal plate and the conductor layer can be ensured by the insulating chemical conversion coating layer 3. Therefore, the insulation reliability at the corner portion 71 is also high. For the above reasons, the insulating chemical conversion coating layer 3
The thickness of the insulating chemical conversion coating layer 3 is preferably 30 μm or more so that the skeleton of the insulating layer 10 of the corner portion 71 can be formed.
However, the insulating resin layer 5 is formed by applying an adhesive and is indispensable for ensuring close contact of the conductor layer at the corner portions of the through-hole portions. In addition, the chemical conversion coating layer 3, which is the lowest insulating layer, may crack when subjected to thermal shock, and such cracks may cause poor insulation in the insulating layer or poor continuity in the conductive layer. In order to prevent this from occurring, the outermost insulating resin layer 5 is necessary.

Further, the portion of the insulating layer 10 that is in contact with the metal plate 1 is a porous chemical conversion coating layer 3, and the surface of this chemical conversion coating layer 3 is a finely roughened surface, so that the metal plate 1 and the insulating layer The adhesion area with 10 is large, and the adhesion between the two is high. Moreover, the chemical conversion coating layer 3 is covered with the electrodeposition coating layer 4, and the porous chemical conversion coating layer 3 is covered with the electrocoating coating layer 4.
Since the pores are sealed with the paint, no air bubbles are formed in the insulating resin layer 5, and the withstand voltage characteristics are good.

Although there is no particular limitation on the method for obtaining the printed wiring board according to the first invention, it is preferable to employ the manufacturing method according to the second invention described below.

Next, the second invention will be explained.

FIGS. 2a to 2k show an embodiment of the method for manufacturing a printed wiring board according to the second invention.

As shown in FIG. 1a, a metal plate 1 is prepared.

Using a drill or the like, a hole 2 for a through hole is formed in the metal plate 1, as shown in FIG. 2b.

Deburr using sandpaper, chemical polishing, electrolytic polishing, etc.

As shown in FIG. 2c, by performing a chemical conversion treatment, an insulating chemical conversion coating layer 3 is formed on the entire surface of the metal plate 1, including the inner wall surface of the hole 2 for the through hole.

As shown in FIG. 2d, an electrodeposition coating layer 4 is deposited on the chemical conversion coating layer 3 by electrodeposition coating. This electrodeposition coating seals the porous chemical conversion coating layer.

As shown in FIG. 2e, an adhesive 5a is applied onto the electrodeposition coating layer 4 on one side 1a by flow coating (curtain coating), and the adhesive is poured into the through-hole holes 2.

By suctioning from the opposite side (non-applied side) 1b, the adhesive inside the through-hole hole 2 is removed so that a layer of adhesive remains on the inner wall surface of the through-hole hole 2, as shown in Fig. 2f. Remove and air dry the remaining adhesive.

As shown in FIG. 2g, on the opposite side 1b, an adhesive 5a is similarly applied on the electrodeposition coating layer 4 by flow coating (curtain coating), and the adhesive is poured into the through-hole holes 2.

Opposite side to the side coated with (the above one side)
By suctioning from 1a, the adhesive inside the through-hole hole 2 is removed so that a layer of adhesive remains on the inner wall surface of the through-hole hole 2, as shown in Fig. 2h, and the remaining adhesive is removed. The insulating resin layer 5 made of adhesive is formed on the electrodeposition coating layer 4 by air drying. Through these steps, an insulating layer 10 consisting of three layers: an insulating chemical conversion coating layer 3, an electrodeposition coating layer 4, and an insulating resin layer 5 is formed on the entire surface of the metal plate 1, including the inner wall surface of the through-hole hole 2. is formed.

While the adhesive of the insulating resin layer 5 is in a semi-cured state, liquid honing or the like is performed to mechanically roughen the surface of the insulating resin layer 5.

As shown in FIG. 2i, an electroless plating layer 61 is formed on the insulating layer 10 (insulating resin layer 5) by performing electroless plating.

As shown in FIG. 2j, the pattern resist 9
After printing, by applying electroplating,
An electroplated layer 62 is formed on a portion that will become an electric path.

Pattern resist 9 is removed.

By etching the entire surface, unnecessary portions of the electroless plating layer 61 are dissolved and removed, leaving only predetermined portions of the conductor layer 6 consisting of the electroless plating layer 61 and the electroplating layer 62, and forming a second layer. Figure k
A printed wiring board having through holes 7 and electric circuits 6a as shown in FIG. 2 is obtained.

As described above, in the manufacturing method of this printed wiring board, the insulating resin layer 5 is made of the adhesive 5a, and its formation is performed on at least the electrodeposition coating layer 4 on one side 1a of the metal plate.
After applying the adhesive 5a thereon, the adhesive 5a inside the hole 2 is applied and suctioned so that a layer of adhesive remains on the inner wall surface of the hole 2 by suctioning from the opposite side 1b. being done. Therefore,
Adhesive can be attached to the inner wall surface of the through-hole hole 2 without clogging the hole. Therefore, printed wiring boards can be obtained with a high yield. In particular, when the inner diameter of the through hole is small, simply applying insulating resin liquid or paste to the surface of the metal plate or immersing the metal plate in the insulating resin liquid will not be able to sufficiently feed the insulating resin into the through hole. Although this may not always be possible, with the method described above, it is possible to reliably suck insulating resin into the through hole and suck out excess insulating resin.

Examples of the metal plate used in the first and second inventions include an aluminum plate, a titanium plate, and an iron plate. The chemical conversion coating layer is limited to one having insulating properties; for example, when the metal plate is an aluminum plate, it becomes an alumite layer, and when the metal plate is an iron plate, it becomes a phosphate layer. As the paint for the electrodeposition paint layer, for example, acrylic melamine, epoxy electrodeposition paint, etc. are used. As the adhesive for the insulating resin layer, the following is disclosed in JP-A-58-81369:
A silicone-modified epoxy resin and NBR (butadiene acrylonitrile rubber) as the main ingredients and a curing agent are mixed therein, and a silicone-modified epoxy resin and NBR as the main ingredients and a curing agent as shown in JP-A-59-81368. Formulated with boron fluoride amine complex, JP-A-59-81370
The silicon-modified epoxy resin shown in the publication
It is preferable to use a material containing NBR as a main ingredient and an aromatic polyamine and a curing accelerator as a curing agent. The reason for this is that with other adhesives, when a conductor layer is formed using an additive method, in order to ensure adhesion between the conductor layer and the insulating resin layer (adhesive layer), chrome It is necessary to roughen the surface of the insulating resin layer with acid, which is not desirable in terms of safety and pollution.However, with the above adhesive, mechanical surface roughening such as liquid honing is required in the semi-cured state. By doing this, it is possible to ensure high adhesion between the conductor layer and the insulating resin layer, especially in the through-holes, so printed wiring boards can be produced safely and without causing pollution. This is because the soldering heat resistance can also be improved.

Copper, nickel, aluminum, gold, or the like is used as the material for the conductor layer. The conductor layer may serve as an electric path, or may be in a state before an electric path is formed. In the above example, the electrical circuit was formed by a so-called semi-additive method using electroless plating and electroplating, but it was performed by a so-called full additive method using only electroless plating. It's okay to be hurt. Alternatively, conductive paste may be used to print on the insulating layer, or a so-called subtractive method may be used, in which a metal foil is placed on the insulating layer and unnecessary parts of the metal foil are removed by etching. It may be done by. As described above, although there are no particular limitations on the method for forming the electric path, if a plating method such as a full additive method or a semi-additive method is used, it is possible to simultaneously form a conductor layer in the through-hole portion and a conductor layer (pattern) on both sides. Moreover, it is preferable to use the plating method because it can omit work steps such as tenting (filling of holes for through holes) that are required in the subtractive method. Furthermore, the plating method has the advantage that the resistance of the through-hole portion is low and electrical performance can be improved. In the above embodiment, the insulating layer covered the entire surface of the metal plate, including the inner wall surface of the through-hole hole, but at least the insulating layer covered the entire surface of the metal plate, including the inner wall surface of the through-hole hole, through the corner, and the surface of the metal plate. It suffices if it covers the area where the layer is to be formed. However, if the entire surface is covered, the metal plate will not be exposed, and the metal of the metal plate will not be dissolved in the treatment liquid during the plating process for forming the conductor layer, which is preferable.
In the first invention, the insulating resin layer is not limited to a layer made only of adhesive, but may also contain prepreg or the like.

Next, examples of the printed wiring board and the manufacturing method thereof according to the present invention will be shown in more detail.

(Example) An aluminum plate with a thickness of 1 mm was prepared.

Diameter 0.6mm on aluminum plate by drilling,
Three types of through holes of 0.8 mm and 1.0 mm were formed.

Deburring was performed using sandpaper.

An aluminum plate was alumite-treated in 15% dilute sulfuric acid at a liquid temperature of 19°C to form an alumite layer with a thickness of 0.5 μm on the entire surface of the aluminum plate, including the inner wall surface of the hole for the through hole.

Acrylic melamine (Electron NO3500R manufactured by Kansai Paint Co., Ltd.) was used as the electrodeposition paint.
After electrodeposition was applied under the conditions of DC 180V and liquid temperature of 22°C, the paint was cured at 180°C for 30 minutes to form an electrodeposition paint layer with a thickness of 20 μm on the alumite layer.

Apply an adhesive of the following composition (viscosity 500 to 600 cps) to a thickness of approximately 100 μm on the electrodeposition coating layer on one side of the metal plate using flow coat (curtain coat).
Adhesive was poured into the hole for the through hole.

[Adhesive composition] Silicone deformed epoxy resin 100g NBR 50g Alumina 150g Curing agent Appropriate amount Solvent Appropriate amount Within 1 minute, apply adhesive onto the inner wall surface of the through-hole hole by suctioning from the opposite side (non-applied side) of the metal plate. The excess adhesive inside the through-hole hole was removed so that a layer of was left behind, and the remaining adhesive was air-dried.

On the other side, the above adhesive was similarly applied to the electrodeposited layer to a thickness of about 100 μm by flow coating (curtain coating), and the adhesive was poured into the through holes.

Within 1 minute, remove the excess adhesive inside the through-hole hole by applying suction from the opposite side to the side where it was applied, leaving a layer of adhesive on the inner wall surface of the through-hole hole, and then air-dry the remaining adhesive. did. Thereafter, the adhesive was cured at 150°C to a semi-cured state.

Liquid honing (A) when the adhesive is semi-hardened
#600 and a pressure of 4 kg/cm ² ) to roughen the surface of the adhesive layer.

By applying electroless copper plating, an electroless copper plating layer with a thickness of about 1 μm was deposited on the adhesive layer.

After printing the pattern resist, electrolytic copper plating is applied to the area that will become the electrical circuit to a thickness of approx.
A 35 μm electrolytic copper plating layer was deposited.

The pattern resist was removed.

By etching the entire surface, unnecessary portions of the electroless copper plating layer were dissolved and removed, leaving only predetermined portions of the conductor layer consisting of the electroless copper plating layer and the electrolytic copper plating layer. Glue layer to 160℃
This was completely cured to obtain a printed wiring board in which through holes and electric circuits were formed. The thickness of the adhesive layer after curing was approximately 15 to 20 μm.

Regarding the printed wiring board obtained as described above, the peel strength (peel strength) at room temperature and in oil at 150°C, the soldering heat resistance for soldering at 260°C, and the through-hole conductor layer and aluminum The withstand voltage between the plate and the insulation resistance between the through-hole conductor layer and the aluminum plate were measured.

As a result, the peel strength at room temperature is 1.5 to 2.5 kg/
cm, peel strength in oil at 150℃ is 0.3~0.3
Kg/cm, soldering heat resistance is 30 seconds or more, insulation resistance between through-hole conductor layer and aluminum plate is diameter
In each through hole part of 0.6mm, 0.8mm, 1.0mm
10 ¹⁰ Ω or more, and the withstand voltage between the conductor layer of the through hole and the aluminum plate was 1000 V or more in each of the through hole portions with diameters of 0.6 mm, 0.8 mm, and 1.0 mm.

As seen from the above results, a printed wiring board with good peel strength, soldering heat resistance, withstand voltage between the through-hole conductor layer and the aluminum plate, and insulation resistance between the through-hole conductor layer and the aluminum plate was obtained. It was done.

In addition, the cross-sectional shape of this printed wiring board is
As shown in the figure, the A dimension was 85 to 90 μm, the B dimension was about 80 μm, and the C dimension was 100 to 120 μm. As can be seen from this result, a sufficient insulation distance can be secured even at the corner portion 71 of the through hole.

The printed wiring board and the manufacturing method thereof according to the present invention are not limited to the above embodiments.

〔Effect of the invention〕

As seen above, in the printed wiring board for through-holes according to the first invention, at least the portion on which the conductor layer is formed on the metal plate in which the holes for the through-holes are formed are covered with an insulating layer, and the insulating layer In the printed wiring board on which a conductor layer is formed, the insulating layer includes an insulating chemical conversion coating layer that covers the surface of the metal plate and the inner wall of the through hole, and an electrodeposition coating layer that covers this chemical conversion coating layer. It is characterized by being composed of three layers, including the electrodeposition paint layer and an insulating resin layer covering the electrodeposition paint layer. Therefore, it has high insulation reliability and can be manufactured with high yield.

In particular, the chemical conversion coating layer, due to its formation principle,
The thickness of the insulating layer is uniform even at the corners of the through-hole, so unlike the conventional insulating layer consisting of only an electrodeposition paint layer or only an insulating resin layer, the thickness of the insulating layer at the corner of the through-hole is This solves the problem that the insulation becomes thinner, making it impossible to secure a sufficient insulation distance and resulting in poor insulation.

However, since the chemical conversion coating layer is porous,
A chemical conversion coating layer alone cannot provide sufficient insulation. In addition, as mentioned above, the fact that the chemical conversion coating layer is formed with a uniform thickness even at the corners of the through hole means that the surface of the chemical conversion coating layer also has sharp edges, and the insulating resin layer is directly applied on top of this. If this is applied, the thickness of the insulating resin layer will become thinner at the corners of the through holes.
Furthermore, by simply applying an insulating resin layer on the chemical conversion coating layer, the insulating resin liquid cannot enter into the fine voids in the chemical conversion coating layer, and the voids remain. This results in a decrease in electrical performance such as insulation or voltage resistance.

Therefore, in this invention, an electrodeposition paint layer is formed on the porous chemical conversion coating layer, and because of its film-forming action, the electrodeposition paint can be applied well to the fine voids in the chemical conversion coating layer. In addition to being able to penetrate and seal the pores, when the electrodeposition paint forms a film, a roundness is formed on the surface even at the corners of the through hole due to the action of surface tension. If an insulating resin layer is formed on the rounded electrodeposition paint layer in this way, a sufficient thickness of the insulating resin layer will also adhere to the corner parts, which will solve the problem of the insulating resin layer becoming thinner at the corner parts. can be resolved.

However, as mentioned above, the fact that the surface of the electrodeposited paint layer is rounded at the corners of the through holes means that the thickness of the electrodeposition paint layer becomes thinner at these parts. Unless an insulating resin layer is formed in advance, the electrodeposition paint layer alone cannot exhibit sufficient insulation at the corners of the through holes. In addition, since the insulating resin layer can be easily formed into a relatively thick film, the overall insulation properties can be further improved compared to an insulating layer consisting only of a chemical conversion coating layer and an electrodeposition coating layer. .

As described above, in this invention, as an insulating layer,
By combining three layers with different properties: a chemical conversion coating layer, an electrocoated paint layer, and an insulating resin layer, it is possible to compensate for each other's shortcomings and take advantage of their strengths. By improving the insulation properties of the through-hole parts, especially the corner parts, which are prone to forming, it becomes possible to exhibit extremely excellent insulation performance as a printed wiring board.

Furthermore, the method for producing a printed wiring board according to the second invention includes performing the steps a to g above to obtain the printed wiring board according to the first invention.
The insulating resin layer can be formed in the through hole without clogging the hole, and the yield can be improved.

In particular, in the process of forming the insulating resin layer, liquid or paste adhesive applied to one side of the metal plate is sucked from the opposite side to form an adhesive layer on the inner wall surface of the through-hole hole. Accordingly, it is possible to reliably form an insulating resin layer of sufficient thickness from the surface of the metal plate to the inner wall surface of the through hole.

This is because simply applying liquid insulating resin to the surface of the metal plate makes it difficult for the insulating resin to penetrate into the small through-holes, resulting in poor insulation within the through-holes. Further, there is a problem that the through-holes cause so-called hole clogging. If the concentration of the insulating resin is reduced or its viscosity is lowered, it will be easier to penetrate into the through-hole and the hole will become less likely to become clogged, but this will reduce the thickness of the insulating tree layer that is formed, and in particular, Only a thin film is formed at the corners of the through holes, resulting in poor insulation. Therefore, in order to form as thick an insulating resin layer as possible at the corners of the through-hole where the thickness of the insulating resin layer tends to be thin, even if a highly viscous insulating resin is used, it is necessary and sufficient to reach the inside of the through-hole. A method that can form an insulating resin layer with a certain thickness is required.

Therefore, in this invention, by performing suction as described above, even highly viscous insulating resin can be reliably drawn into the through-hole hole, and excess insulating resin can be suctioned and removed from the through-hole hole. This makes it possible to reliably form an insulating resin layer with a necessary and sufficient thickness on the inner wall surface of the through-hole.

In particular, even when the present invention is applied to a through-hole with a small inner diameter, it is possible to reliably form an insulating resin layer with a necessary and flexible thickness on the inner wall surface of the through-hole, which is not possible with conventional ordinary insulating layer forming means. It also becomes possible to manufacture printed wiring boards with small-diameter through holes, which would otherwise be impossible.

Next, in the method for manufacturing a printed wiring board for through-holes as described above, if the conductor film is formed by at least one of the full additive method and the semi-additive method, the conductor film formation step can be improved. It becomes easier, and the electrical resistance in the through-hole part decreases,
It becomes possible to manufacture printed wiring boards with excellent electrical performance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the printed wiring board according to the first invention, and FIGS.
FIG. 3 is a cross-sectional view of the through-hole portion of the printed wiring board obtained by the embodiment of the second invention, and FIG. 4 is a conventional FIG. 2 is an explanatory diagram showing a method for manufacturing a printed wiring board. 1...Metal plate 1a...One side of metal plate 1b...
...Opposite side of metal plate 2 ... Hole for through hole 3
...Chemical conversion coating layer 4...Electrodeposition paint layer 5...
Insulating resin layer 5a...Adhesive 6...Conductor layer 6
a...Electric circuit 7...Through hole 10...Insulating layer.

Claims (1)

[Claims] 1. A printed wiring board for through-holes, in which at least a portion of a metal plate in which holes for through-holes are formed is covered with an insulating layer, and a conductor layer is formed on the insulating layer. The insulating layer comprises an insulating chemical conversion coating layer covering the metal plate and the inner wall surface of the through hole, an electrodeposition coating layer covering the chemical conversion coating layer, and an adhesive covering the electrodeposition coating layer. A printed wiring board for through-holes characterized by being composed of three layers including an insulating resin layer. 2. A method for manufacturing a printed wiring board for through-holes, in which at least the part on which a conductor layer is formed on a metal plate in which holes for through-holes are formed is covered with an insulating layer, and a conductor layer is formed on the insulating layer. A method for producing a printed wiring board for through-holes, the method comprising the following steps a to g. a Step of forming holes for through holes in the metal plate b Step of forming a chemical conversion coating layer on at least the portion where the conductor layer is formed on the metal plate and the through hole portion c An electrodeposition paint layer covering the chemical conversion coating layer Step d: Applying an adhesive on the electrodeposited paint layer on one side of the metal plate and the through-holes Step e: Applying adhesive from the opposite side of the metal plate, leaving an adhesive layer on the inner wall surface of the through-hole hole, step f of removing the adhesive from the opposite side of the metal plate in the same manner as steps d and e above, and step g of forming an insulating layer with adhesive on the insulating layer. Step 3 of forming a conductor layer on
A method for manufacturing a printed wiring board for through-holes according to claim 2, which is carried out by a different method.