JPH0918140A - Production of printed wiring board - Google Patents

Abstract

PURPOSE: To produce a printed wiring board having a core of aluminum plate in which the heat dissipation performance and heat shock resistance are enhanced. CONSTITUTION: An aluminum plate 2 having through holes 1 is subjected to electrolytic processing for 8-30sec using an alkaline solution at bath temperature of 40-90 deg.C by applying an AC waveform at an electric quantity of 80-250C/dm<2> . After filling the through hole 1 with a resin 3, a circuit body is laminated on the aluminum plate 2. A through hole 7 is then made at the part of through hole 1 filled with resin 3 and a through hole is made through the aluminum plate 2 at a part other than the through hole 1 before the inner circumference of each through hole 7 is subjected to through hole plating 16a, 16b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board having an aluminum plate as a core.

[0002]

2. Description of the Related Art In recent years,
Printed wiring boards are rapidly becoming multilayered and highly densified as electronic devices have become more functional, lighter, thinner, smaller and smaller. For this reason, there is an increasing need to radiate heat generated from electronic components, and a printed wiring board using an aluminum plate having excellent thermal conductivity as a core is provided.

When an aluminum plate is used as the core of the printed wiring board as described above, it is necessary to ensure insulation between the aluminum plate and the through hole formed in the printed wiring board for circuit conduction. For this purpose, various measures have been taken such as using an aluminum plate having a through hole. That is, as shown in FIG. 8A, the aluminum plate 2 having the through holes 1 is filled with the resin 3 to fill the holes, and in this state, the aluminum plate 2 is inserted through the prepreg 4 as shown in FIG. 8B. The copper foil 5 is overlaid, and this is heat-pressed and molded.
After laminating the copper foil 5 on the aluminum plate 2 via the insulating adhesive layer 6 by the prepreg 4 as shown in FIG. 8C, FIG.
As described above, the through hole 7 is bored in the inner periphery of the through hole 1 at the position of the resin 3, the through hole plating 16a is applied to the inner periphery of the through hole 7, and the copper foil 5 is etched to form the circuit 17. The printed wiring board A as shown in FIG. 8E can be manufactured. The through hole 7 thus formed can ensure the insulation between the aluminum plate 2 and the resin 3 with which the through hole 1 is filled.

However, in this structure, the surface of the aluminum plate 2 is covered with an insulating adhesive layer 6 made of a resin having a low heat conductivity, and the through hole 1 formed in the aluminum plate 2 is used.
Also, the inner circumference of the aluminum plate 2 is covered with the resin 3 for filling holes, so that it is difficult to dissipate heat from the aluminum plate 2. Therefore, although the aluminum plate 2 having excellent thermal conductivity is used as the core, there is a problem that the heat radiation effect cannot be sufficiently obtained.

Further, the adhesion between the inner peripheral surface of the through hole 1 of the aluminum plate 2 and the hole filling resin 3 and the aluminum plate 2
The adhesiveness between the surface of the aluminum plate 2 and the insulating adhesive layer 6 is not sufficient, and the surface of the aluminum plate 2 is insulated from the interface between the through hole 1 of the aluminum plate 2 and the filling resin 3 when a thermal shock is applied by high temperature heating. Micro cracks (fine cracks that cannot be confirmed by normal visual inspection) occur at the interface with the adhesive layer 6,
If the generation of microcracks is severe, it leads to blistering and peeling. Therefore, in order to improve the adhesion between the through hole 1 of the aluminum plate 2 and the hole filling resin 3 and the adhesion between the surface of the aluminum plate 2 and the insulating adhesive layer 6, various types of aluminum plates 2 are treated. Methods are being considered.

For example, the method disclosed in Japanese Patent Laid-Open No. 6-152089 is effective for an aluminum plate. However, in this method, degreasing, water washing, surface etching of aluminum plate (electrolysis or immersion), water washing, activation, water washing, zinc alloy replacement treatment, water washing, nickel plating (electrolytic or electroless), water washing, activation, copper sulfate There is a problem that many steps (22 steps in total) of plating, washing with water, blackening treatment (8 steps), and drying are necessary, and the chemicals used are difficult to handle, such as hydrofluoric acid and nitric acid. However, due to safety and environmental issues, it has not been put to practical use.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to improve heat dissipation performance and thermal shock resistance in a printed wiring board having an aluminum plate as a core. It is a thing.

[0008]

A method for manufacturing a printed wiring board according to claim 1 of the present invention is a method for producing an electric quantity of an aluminum plate 2 having a through hole 1 by using an alkaline solution having a bath temperature of 40 to 90 ° C. After electrolytic treatment is performed for 8 to 30 seconds with an AC waveform at 80 to 250 C / dm ² , resin 3 is filled in the through hole 1 to fill the hole, and then the aluminum plate 2 is filled with the circuit body 13
Through holes 7 are formed by laminating the through holes 7 at positions where the resin 3 of the through holes 1 is filled and through the aluminum plate 2 at positions other than the through holes 1.
Is perforated and through-hole plating 16a, 16b is applied to the inner periphery of each through-hole 7, 15.

According to the second aspect of the present invention, the land 1 is formed in the opening of the through hole 15 provided so as to penetrate the aluminum plate 2.
8b is formed. The invention according to claim 3 is characterized in that the inside of the through hole 15 provided so as to penetrate the aluminum plate 2 is filled with the resin 14. Hereinafter, the present invention will be described in detail.

The aluminum plate 2 is not particularly limited, but preferably has a thickness of 0.3 to 2.0 mm. The aluminum plate 2 is preferably pure aluminum, but other elements than Al, such as Mn and M, are used.
The content of g, Zn, Cr, Fe, Si, etc. is 0.8% by weight.
The following are preferable. When the aluminum plate 2 in which the content of the impurity element other than Al exceeds 0.8% by weight is used, it seems that the electrolytic treatment is apparently performed at the time of the electrolytic treatment described later, but locally. Causes unevenness of treatment, and the aluminum plate
There is a risk of causing peeling between the resin and the resin 3.

First, as shown in FIG. 2 (a), a through hole 1 is drilled in a desired portion of the aluminum plate 2.
The through hole 1 is formed at a place where the through hole 7 is provided, and is formed as a hole having a diameter larger than that of the through hole 7. The aluminum plate 2 provided with the through holes 1 in this manner is subjected to electrolytic treatment. This electrolytic treatment can be carried out by a method which is an improvement of the "aluminum plate surface treatment method" provided in JP-A-63-258674. That is, the aluminum plate 2 is electrolyzed for 8 to 30 seconds by an AC waveform with an electric quantity of 80 to 250 C / dm ² using an alkaline solution having a bath temperature of 40 to 90 ° C.

Here, the electrolytic solution used for the electrolytic treatment may be any alkaline solution, and the kind thereof is not particularly limited, but usually an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium phosphate or the like. Alternatively, it is preferable to use a mixed solution of two or more of these, and a surfactant may be contained in order to improve the degreasing property. The pH of the alkaline solution used as this electrolytic solution is preferably 9 to 13. When the pH is less than 9, the degreasing property is poor, and the bath voltage is increased to cause non-uniform electrolysis, which is not preferable. On the other hand, if the pH exceeds 13, the solubility is too strong and an anodic oxide film having a required thickness cannot be obtained, which is not preferable. The bath temperature of the alkaline solution is 4 as above.
It is necessary to be in the range of 0 to 90 ° C, and at a low temperature of less than 40 ° C, the degreasing / cleaning effect cannot be sufficiently obtained.
When it exceeds, the solubility is too strong to obtain an anodized film having a required thickness. Even within the range of 40 to 90 ° C, the range of 60 to 80 ° C is particularly preferable.

As the counter electrode used for the electrolytic treatment, an aluminum plate, an iron plate, a graphite electrode or the like can be used.
Further, the current waveform in the electrolytic treatment needs to be an AC waveform. By using an AC waveform, a strong degreasing and cleaning effect can be obtained by alternating anodic reaction and cathodic reaction, and at the same time, electrolysis can be performed at a high current density for a short time without rough skin, and corrosion resistance. The property can also be made superior to that in the case of direct current electrolysis. The AC waveform need only be a waveform that alternates between the + side and the-side, and does not necessarily have to be a sine wave. The alternating current may be either single-phase or three-phase.

The amount of electricity in the electrolytic treatment (total amount of electricity from the start to the end of electrolysis) is 80 to 250 as described above.
It must be in the range of C / dm ² . 80 C / d
If it is less than m ² , a sufficient degreasing / cleaning effect cannot be obtained, and an anodized film having a required thickness cannot be obtained.
Even if a large amount of electricity exceeding dm ² is applied, the anodic oxide film does not grow any more and is economically useless. The electrolysis time in the electrolysis treatment is 8 to 30 seconds. Electrolysis time is 8
If it is less than a second, when the quantity of electricity is close to the lower limit of the above range, sufficient degreasing and cleaning effects cannot be obtained, and an anodized film having a required film thickness cannot be obtained. Electrolysis time is 30
Even if it exceeds the second, the anodic oxide film does not grow any more, which is economically wasteful. The current density is determined from the above-mentioned amount of electricity and electrolysis time, but is preferably 5 to 15 A / dm ² . When the current density is less than 5 A / dm ² , the electrolysis time becomes long, and when it exceeds 15 A / dm ² , the surface of the aluminum plate 2 may be partially heated to cause surface roughness.

By performing the electrolytic treatment as described above, an anodized film having a thin film thickness of about 0.01 to 0.05 μm is formed on the surface of the aluminum plate 2 including the inner peripheral surface of the through hole 1. This anodic oxide film is dense and has high corrosion resistance.
The surface of the aluminum plate 2 including the inner peripheral surface can be formed into a rough uneven surface. Here, in performing the electrolytic treatment as described above, the aluminum plate 2
If oil adheres to the surface of the aluminum plate, it is pre-degreased, then washed with water, and then, if the aluminum plate 2 contains an impurity element such as Mg, it is pickled, washed with water, and after the above electrolytic treatment, , Wash with deionized water, and
The process can be completed by hot-air drying at a temperature of 130 ° C., and thus the process can be completed in 7 steps, and the number of steps can be significantly reduced compared to the conventional 22 steps. is there.

After electrolytically treating the aluminum plate 2 having the through holes 1 formed as described above, the through holes 1 are filled with the resin 3 as shown in FIG. 2B. Although a thermosetting resin is used as the resin 3, it is preferable to use an epoxy acrylate-based photocurable resin or an epoxy-based thermosetting resin. It is preferable that the resin 3 be used by blending an inorganic filler. The inorganic filler can be used without particular limitation as long as it has electrical insulating properties such as silica, alumina, mica, calcium sulfate, glass powder, and talc, but the particle size thereof is 3 to 70 μm. Is preferred. The addition amount of the inorganic filler is preferably in the range of 30 to 70% by weight with respect to the resin 3. After filling the through hole 1 with the resin 3 to fill the hole,
The resin 3 is semi-cured or cured.

After the through hole 1 is filled with the resin 3 as described above, the circuit body 13 is superposed on both surfaces of the aluminum plate 2 via the prepreg 4 as shown in FIG. 2 (c). FIG.
In the example of (c), the copper foil 5 is used as the circuit body 13. Then, this is heat-pressed and laminated to form a circuit body 13 on both surfaces of the aluminum plate 2 with an insulating adhesive layer 6 formed of a prepreg 4 interposed therebetween, as shown in FIG.
A laminated board in which (copper foil 5) is laminated can be obtained.

Next, as shown in FIG. 2 (e), a through hole 7 is bored at a position passing through the through hole 1 in the portion of the resin 3 filled with the hole by using an NC drill machine or the like. Then, in the present invention, at this time, in addition to the through hole 7, the through hole 15 is drilled so as to penetrate the aluminum plate 2 at a position other than the through hole 1. Therefore, a part of the aluminum plate 2 is exposed on the inner periphery of the through hole 15.

After that, copper plating or the like is performed on the inner circumferences of the through holes 7 and 15 to form the through holes 16a and 16b.
Then, the copper foil 5 is subjected to etching and the like, so that the circuit 17 and the lands 18a,
18b can be formed to finish the printed wiring board A as shown in FIG. Here, the land 18a produced by connecting to the through hole plating 16a of the through hole 7 provided so as to pass through the through hole 1 is electrically connected to the circuit 17.
The circuits 17 on both sides can be electrically connected by a. The land 18b connected to the through hole plating 16b of the through hole 15 provided so as to penetrate the aluminum plate 2 is not electrically connected to the circuit 17.

Incidentally, FIG. 3 shows another embodiment of the production of the laminated board. In the example of FIG. 3 (a), after the circuit 17 is formed on the surface of the aluminum plate 2 (the circuit 17 is formed as described above). It can be performed in the same manner as the above), but the copper foil 5 is laminated as the circuit body 13 on both sides of the prepreg 4 via the prepreg 4. Further, in the example of FIG. 3B, the circuit board 1 produced by forming the circuit 17 on the inner surface and sticking the copper foil 5 on the outer surface.
The circuit body 9 is laminated on both surfaces of the aluminum plate 2 via the prepreg 4. This figure 3
With (a) and (b), a multilayer printed wiring board having a four-layer circuit structure can be manufactured.

Further, as described above, the through holes 7, 15
In general, electroless plating such as chemical copper plating is often performed when the through holes 16a and 16b are applied to the inner circumference of the through hole 15. However, in the case of electroless plating, a strong acid or a strong alkali is used. There is a risk that the aluminum plate 2 exposed on the inner periphery of the will be corroded. Therefore, at this time, a weak alkaline solution in which fine particles of a conductive substance such as carbon black or graphite are dispersed with a surface active agent is used, and the laminated plate having the through holes 7 and 15 processed is dipped in the weak alkaline solution, or The weak alkaline solution is sprayed onto the laminated plate having the through holes 7 and 15 processed so that the conductive fine particles are attached to the inner periphery of the through holes 7 and 15, and thereafter, a plating bath such as an electrolytic copper plating bath is applied. By immersing the laminated plate and energizing the layer of conductive fine particles, the inner periphery of the through holes 7, 15 is simultaneously plated with the through holes 16a, 16a by electroplating.
16b may be applied. The process of using a weak alkaline solution in which carbon black fine particles are dispersed with a surfactant is provided as "Black hole process" of Japan MacDermid Co., Ltd. Also, a weak alkaline solution in which graphite fine particles are dispersed with a surfactant is used. The process is provided as "S process" of MEC.

In the printed wiring board A manufactured as shown in FIG. 1, however, the through hole 7 provided so as to pass through the through hole 1 has the resin 3 filled in the through hole 1 between the aluminum plate 2 and the through hole 7. Due to the interposition, it is possible to ensure electrical insulation between the through hole plating 16a formed in the through hole 7 and the aluminum plate 2. Further, since a part of the aluminum plate 2 is exposed in the through hole 15 provided so as to penetrate the aluminum plate 2, the aluminum plate 2
Is radiated satisfactorily from the through hole 15. Moreover, since the through hole plating 16b provided on the inner circumference of the through hole 15 is in contact with the aluminum plate 2, the heat of the aluminum plate 2 is applied to the through hole plating 16b.
The heat is further dissipated through the heat transfer, and the heat dissipation can be further improved.

When a land 18a connected to the through hole plating 16b is provided in the opening of the through hole 15, a heat generating component 20 such as an electronic component such as an IC chip is brought into contact with the land 18a as shown in FIG. When the heat-generating component 20 is mounted on the printed wiring board A in this manner, the heat generated from the heat-generating component 20 becomes through-hole plating 16b.
The aluminum plate 2 is electrically heated through the through hole 15 and is radiated from the through hole 15, so that the heat radiation effect from the heat generating component 20 can be improved. In addition, this land 1 is installed in the casing that incorporates the printed wiring board A.
By contacting 8a, heat can be transferred from the aluminum plate 2 through the through-hole plating 16b to the casing for heat dissipation. It is preferable that the land 18a has a diameter of 3 mm or more when it is circular, and has a side of 3 mm or more when it is quadrangular.

Further, it is preferable that the inner periphery of the through hole 15 is filled with resin 14 as shown in FIG. If the inside of the through hole 15 is hollow, the heat radiation effect by the air flow can be expected, but in reality, the effect by the air flow cannot be expected because the diameter of the through hole 15 is small. On the other hand, if the inner periphery of the through hole 15 is filled with the resin 14, the heat capacity in the through hole 15 increases, so that the heat conduction from each part of the printed wiring board A concentrates on this part, and the heat dissipation is improved. is there. Further, by filling the through hole 15 with the resin 14 and filling the hole as described above, it is possible to prevent the heat generating component 20 from being corroded through the cavity of the through hole 15. As a specific example of the resin 14 that fills the through hole 15, an epoxy acrylate resin (“OPSR580 manufactured by Tokyo Ohka Kogyo Co., Ltd.”) is used.
0 ”) and 100 parts by weight of alumina filler added with 120 parts by weight. The resin 14 is filled in the through hole 15 and then cured by ultraviolet rays with a light amount of 1 J, and further heated at 150 ° C. for 15 minutes to be cured. Moreover, the thing which added 150 weight part of silica to 100 weight part of epoxy resins ("Epicoat Ep828" by Yuka Shell Co., Ltd.) can also be mentioned. This resin 14
After being filled in the through hole 15, it is heated at 150 ° C. for 40 minutes to be cured.

Since the aluminum plate 2 has been subjected to the electrolytic treatment as described above, the surface of the aluminum body 2 has an anodized film formed on the inner periphery of the through hole 1.
This anodized film enhances the adhesion between the inner periphery of the through hole 1 and the resin 3 for filling the hole, and the aluminum plate 2
The adhesion between the surface of the and the resin of the insulating adhesive layer 6 is increased,
It is possible to prevent the generation of microcracks at these interfaces. Therefore, the printed wiring board A has high heat resistance.

[0026]

EXAMPLES The present invention will now be illustrated by way of examples. (Example 1) A through hole 1 having a diameter of 1.5 mm was formed in an aluminum plate 2 having a thickness of 0.8 mm. Then, an electrolytic solution containing 1% by weight of sodium pyrophosphate, 1% by weight of sodium hydroxide, and 1% by volume of a nonionic surfactant (pH 11,
Al ³⁺ ions in the liquid <0.3 g / liter) were adjusted to a bath temperature of 50 ° C., the aluminum plate 2 was immersed in this electrolytic solution, and a graphite electrode was used as a counter electrode to form a single-phase alternating current (50 Hz sine wave). The current density is 8 A / dm ² , and the quantity of electricity is 24
It was electrolyzed for 30 seconds under the condition of 0 C / dm ² , washed with water and dried.

On the other hand, an epoxy resin varnish was prepared with a compounding composition of 100 parts by weight of tetrabromobisphenol A type epoxy resin (epoxy equivalent of 500 g / eq), 1.2 parts by weight of dicyandiamide, and 0.1 parts by weight of 2 ethyl 4-methylimidazole. Mica having an average particle size of 3 μm was added to this resin varnish as an inorganic filler in an amount of 30% by weight of the resin content to prepare a resin 3 for filling holes. Then, this resin 3 is put through hole 1
And was held at 130 ° C. for 15 minutes to semi-harden the resin 3 (FIG. 2 (b)).

Next, two 0.1 mm thick epoxy resin prepregs ("R-1661J" manufactured by Matsushita Electric Works, Ltd.) were stacked on each of the upper and lower surfaces of the hole-filled aluminum plate 2, and copper having a thickness of 18 μm was further provided on the outside thereof. Stack foil 5
A double-sided copper-clad laminate was obtained by heat-press molding under conditions of a temperature of 170 ° C., a pressure of 20 kg / cm ² , and a time of 90 minutes (FIG. 2 (d)).

Next, with respect to the double-sided copper-clad laminate, a through hole 7 having a diameter of 0.35 mm is punched at the center of the through hole 1 and the aluminum plate 2 having a diameter of 3. 5mm through hole 1
5 was perforated (FIG. 2 (e)). Then, on the inner periphery of the through holes 7 and 15, copper through hole plating 16a,
16b, and the copper foil 5 is further etched to form lands 18a with a diameter of 3 mm around the through holes 7 and 15,
18b was formed. Then, a solder resist was applied on the surface to obtain a printed wiring board A (FIG. 1).

Example 2 With respect to the printed wiring board A before applying the solder resist obtained in the same manner as in Example 1, the resin 14 was filled in the inner periphery of the through hole 15 (see FIG. 5). As the resin 14, an epoxy acrylate resin (“OPSR5800” manufactured by Tokyo Ohka Kogyo) 1
Using 100 parts by weight of alumina filler added to 120 parts by weight, the resin 14 is applied by printing into the through-holes 15 and then cured by UV with a light amount of 1 J and
It was cured by heating at 50 ° C. for 30 minutes. Then, a solder resist was applied on the surface to obtain a printed wiring board A.

Comparative Example 1 A 1.6 mm thick double-sided copper-clad epoxy resin laminated plate (“R-1705SX” manufactured by Matsushita Electric Works, Ltd.) without an aluminum plate as a core was used, and the diameter was 0.3.
A 5 mm through hole was drilled in the same manner as in Example 1, through hole plating was performed in the same manner as in Example 1, land was formed in the same manner as in Example 1, and a solder resist was applied to the surface. Then, a printed wiring board was obtained.

(Comparative Example 2) Except that the through hole 15 penetrating the aluminum plate 2 is not provided (thus, the through hole plating 16b and the land 18b are not provided).
A printed wiring board A was obtained in the same manner as in Example 1 (FIG. 8).
(E)). (Comparative Example 3) A printed wiring board A was obtained in the same manner as in Example 1 except that the aluminum plate 2 which was not subjected to the electrolytic treatment according to Example 1 was used (without filling the through holes 15).

(Comparative Example 4) A printed wiring board A was obtained in the same manner as in Example 2 except that the aluminum plate 2 which was not subjected to the electrolytic treatment according to Example 1 was used (the through hole 15 was filled). ). FIG. 6A shows 70 mm × 70 manufactured from the printed wiring boards obtained in Example 1 and Example 2.
₁ shows a test piece A ₁ having a size of mm, a copper foil 5 having a size of 21 mm × 18 mm is left on only one surface, and a through hole 1
There are 16 through-holes 7 passing through and two through-holes 15 penetrating the aluminum plate 2, and a mounting hole 21 (without through-hole plating) having a diameter of 3.5 mm is provided in the copper foil 5. is there. Further, FIG. 6B shows a test piece A ₂ produced from the printed wiring boards obtained in Comparative Example 1 and Comparative Example 2, except that the through hole 15 penetrating the aluminum plate 2 is not provided. Same as a). Then, a bipolar power transistor (package type TO-3P, allowable collector loss Pc = 50 W as a heat generating component 20 is provided on the copper foil 5 of each of the test pieces A ₁ and A _2.
(Tc = 25 ° C)) and put the screw 2 through the mounting hole 21.
2. The temperature of the screw 22 is fixed by the ΔV _BE method (using the temperature characteristic of the base-emitter voltage of the transistor,
The temperature rise is measured by the voltage difference before and after energization of the transistor). The measurement uses a thermal resistance measuring device ("TH-155A" manufactured by Kuwabara Electric Co., Ltd.) as a measuring device.
The application conditions were V _CB = 10 (V) and IE = 0.3 (A). Then, the measured temperature rise was compared between Examples 1 and 2 and Comparative Examples 1 and 2, and the heat dissipation was evaluated as Comparative Example 100. The results are shown in Table 1.

Further, the printed wiring boards obtained in Examples 1 and 2 and Comparative Examples 1 to 4 were cut into 30 mm × 30 mm to prepare test pieces, which were placed in a solder bath at 260 ° C.
A thermal shock resistance test is conducted by immersing it twice for 2 seconds each, followed by boiling for 2 hours, and then a thermal shock resistance test is conducted by immersing it in a solder bath at 260 ° C twice for 10 seconds each time. Micro cracks between the aluminum plate and resin The state of occurrence of peeling and peeling was observed. Each test is performed on 5 test pieces,
No abnormality was evaluated as “◯”, occurrence of microcracks was evaluated as “Δ”, and occurrence of large cracks or occurrence of peeling was evaluated as “x”.
The results are shown in Table 1.

[0035]

[Table 1]

As can be seen from the results shown in Table 1, it is confirmed that the heat dissipation properties of Examples 1 and 2 having through holes penetrating the aluminum plate are high. It is also confirmed that the electrolytic treatment of the aluminum plate improves the heat resistance as in Examples 1 and 2.

[0037]

As described above, according to the present invention, after the resin is filled in the through holes to fill the holes, the circuit board is laminated on the aluminum plate, and the through holes are drilled at the portions of the through holes filled with the resin. At the same time, the through holes that penetrate the aluminum plate are drilled at locations other than the through holes, and the through holes are plated on the inner circumference of each through hole. The heat of the aluminum plate can be radiated through the through-hole plating, and the heat radiation performance of the printed wiring board having the aluminum plate as the core can be improved. 8 ~ by AC waveform with electricity of 80 ~ 250 C / dm ² using alkaline solution at ~ 90 ° C
Since the electrolysis treatment is performed for 30 seconds, the electrolysis treatment can improve the adhesion between the aluminum plate and the resin with a reduced number of treatment steps and enhance the thermal shock resistance.

Further, since the land is formed in the opening of the through hole provided so as to penetrate the aluminum plate, the heat generated by the heat generating component can be released to the aluminum plate by bringing the heat generating component into contact with this land. Therefore, the temperature rise of the heat generating component can be effectively prevented. Furthermore, since the through hole provided so as to penetrate the aluminum plate is filled with resin,
The heat dissipation can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a printed wiring board according to an embodiment of the present invention.

FIG. 2 shows an embodiment of the present invention,
(A)-(e) is sectional drawing of each process of manufacture, respectively.

FIG. 3 illustrates another aspect of the practice of the invention,
(A), (b) is a sectional view, respectively.

FIG. 4 is a partial enlarged cross-sectional view showing another embodiment of the present invention.

FIG. 5 is a partial enlarged cross-sectional view showing another embodiment of the present invention.

FIG. 6 shows a test piece, and (a) and (b) are plan views, respectively.

FIG. 7 is a cross-sectional view showing a test.

FIG. 8 shows a conventional example, and FIGS. 8A to 8E are cross-sectional views of respective manufacturing steps.

[Explanation of symbols]

 1 Through Hole 2 Aluminum Plate 3 Resin 7 Through Hole 13 Circuit Body 14 Resin 15 Through Hole 16a Through Hole Plating 16b Through Hole Plating

[Procedure amendment]

[Submission date] October 9, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

First, as shown in FIG. 2 (a), a through hole 1 is drilled in a desired portion of the aluminum plate 2.
The through hole 1 is formed at a place where the through hole 7 is provided, and is formed as a hole having a diameter larger than that of the through hole 7. The aluminum plate 2 provided with the through holes 1 in this manner is subjected to electrolytic treatment. The electrolytic treatment is next
It can be carried out in a way. That is, the bath temperature is 40 to 9
Electricity of 80-250C using 0 ° C alkaline solution
Aluminum plate 2 8-3 by AC waveform at / dm ²
The electrolytic treatment is performed for 0 seconds.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Further, if provided with lands 18 b to be connected to the through-hole plating 16b to the opening of the through hole 15, the electronic components such as heat-generating components 20 such as an IC chip on this land 18 b as shown in FIG. 4 When the heat-generating component 20 is mounted on the printed wiring board A so as to be in contact with each other, the heat generated from the heat-generating component 20 is through-hole plated 16b.
The aluminum plate 2 is electrically heated through the through hole 15 and is radiated from the through hole 15, so that the heat radiation effect from the heat generating component 20 can be improved. In addition, this land 1 is installed in the casing that incorporates the printed wiring board A.
By contacting 8b , heat can be transferred from the aluminum plate 2 to the casing through the through-hole plating 16b to radiate heat. The land 18 b is a circular diameter of 3mm or more, in the case of a square preferably formed to a size of more than one side 3mm.

Claims (3)

[Claims] 1. An aluminum plate having a through hole is charged with an electric quantity of 80 to 2 by using an alkaline solution having a bath temperature of 40 to 90 ° C.
Electrolytic treatment for 8 to 30 seconds with an alternating current waveform at 50 C / dm ² , after filling the through holes with resin and filling the holes, the circuit board is laminated on this aluminum plate, and the portions of the through holes filled with the resin In the method of manufacturing a printed wiring board, the through hole is drilled, the through hole penetrating the aluminum plate at a position other than the through hole is drilled, and the through hole is plated on the inner circumference of each through hole. 2. The method for manufacturing a printed wiring board according to claim 1, wherein a land is formed in an opening of a through hole provided so as to penetrate the aluminum plate. 3. The method for manufacturing a printed wiring board according to claim 1, wherein the through hole provided so as to penetrate the aluminum plate is filled with resin.