JP2005179695A - Wiring substrate and method for forming electric wiring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate provided with electric wiring having adequate adhesiveness to the substrate and low resistance, and to provide a method for forming the electric wiring for simply forming the electric wiring having adequate adhesiveness to an article to have the electric wiring thereon. <P>SOLUTION: The wiring substrate has the electrical wiring with a layered structure obtained by layering the first layer consisting of an electroless nickel-cobalt-phosphor-plated film containing cobalt in a range of 0.1 to 20 wt.%, and the second layer consisting of an electroless copper-plated film from the substrate side in this order. The method for forming the electrical wiring comprises the steps of: forming the electroless nickel-cobalt-phosphor-plated film as the first layer containing cobalt in a range of 0.1 to 20 wt.% into an electrode wiring pattern; heat-treating the electroless nickel-cobalt-phosphor-plated film for increasing the adhesive strength; and forming the electroless copper-plated film as the second layer on the electroless nickel-cobalt-phosphor-plated film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wiring board and a method for forming an electric wiring, and more particularly, to a wiring board used for various flat displays, various electric circuit boards, and the like, and a method for forming an electric wiring that can be used for the electric wiring formation of the wiring board. .

Flat displays such as liquid crystal display devices (LCD), plasma display devices (PDP), electrochromic display devices (ECD), and electroluminescent display devices (FLD) usually have a pair of display materials such as liquid crystal and discharge gas. It is held between the glass substrates, and a voltage is applied to the display material. At this time, electrical wiring is formed of a conductive material on at least one of the substrates. In recent years, with the increase in the size of flat displays, glass substrates used in the manufacturing process have become larger year by year, and electrical wiring can be formed on a large area substrate having a side length of about 1 m and an area of about 1 m ^2. It is requested. Conventionally, electrical wiring has been formed by forming a metal thin film of Ta, Al, Mo, etc. on the entire surface of a glass substrate by a vacuum film formation method such as sputtering or CVD, and providing an etching resist on this to remove unnecessary portions by etching. Was formed.

However, in conventional electrical wiring formation on a large area substrate, it is difficult to make the film thickness and quality of the metal thin film uniform, and enormous capital investment is required to increase the size of the vacuum film forming apparatus. There is a problem that the manufacturing cost increases. Furthermore, the increase in the size of the vacuum film forming apparatus requires a large amount of electric power for driving the vacuum pump, heating the substrate, generating plasma, etc. This also increases the manufacturing cost and increases the energy consumption. Was against the environmental challenge of reducing carbon dioxide emissions to prevent global warming.
In order to solve such a problem, a method of forming an electrical wiring using a wet film forming method has been proposed. For example, Patent Document 1 discloses a method in which a transparent electrode made of indium tin oxide (ITO) or the like is used as a base film, and a metal film such as copper or nickel is formed on the base film by a plating method. . In this electric wiring forming method, since the vacuum film forming apparatus is not used for forming the metal film, the above problems are solved.

  Further, in the above wet film formation method, the formation of the base film such as ITO still uses a vacuum film formation method such as a sputtering method or a vapor deposition method, but as disclosed in Patent Document 2, A method of forming a thin film such as ITO as a base film by a wet film forming method has been found, and a method of forming an electrical wiring in which all are performed by a wet film forming process has been proposed.

On the other hand, the formation of electrical wiring by a vacuum film forming method is widely used in the manufacture of LSIs in addition to flat displays. Conventionally, LSIs consolidate functions on a single chip of several millimeters square, and external wiring is formed on a metal conductive frame or resin substrate from that chip. Recently, however, MCM (Multi Tip Module) and SIP (System In Package) are beginning to appear. As LSIs become more sophisticated, heat generation during operation also increases, and as a substrate for MCM or SIP, instead of a resin-based substrate having a larger thermal expansion coefficient than that of the LSI chip, thermal expansion equivalent to that of the LSI chip is achieved. A silicon-based substrate having a coefficient is preferably used. In recent years, a method for manufacturing an LSI has also adopted the formation of a multilayer structure in which a first layer by electroless nickel plating and a second layer by electroless copper plating are laminated.
JP-A-4-232922 JP 2001-32086 A

However, when the electroless copper plating of the second layer is directly applied when forming the multilayer structure film having the electroless nickel plating as the first layer, the catalytic activity for the electroless copper plating of nickel is not sufficient, There was a problem that precipitation of plating hardly occurred. In addition, depending on the washing conditions, the electroless nickel plating film may be oxidized in water and become an inactive state, which causes a decrease in yield in mass production industrially.
Furthermore, immediately after the electroless nickel plating, the adhesion between the electroless nickel plating film and the ITO or glass substrate is low, and peeling occurs between the ITO or glass substrate and the electroless nickel plating film during the electroless copper plating process. May end up. In order to prevent this peeling, it is necessary to improve the adhesion between the electroless nickel plating film and the ITO or glass substrate by performing a heat treatment at 150 to 250 ° C. for about 30 to 60 minutes after the electroless nickel plating. However, this heat treatment has a problem of simultaneously oxidizing the electroless nickel plating film and degrading the catalytic ability of the electroless copper plating reaction.

By performing the above heat treatment in a vacuum furnace, a nitrogen substitution furnace, a reduction furnace that performs heat treatment in a reducing gas atmosphere, etc., it is possible to prevent oxidation of the electroless nickel plating film and deterioration of the catalytic performance of the electroless copper plating reaction. it can. However, these furnaces all increase the manufacturing cost and are ineffective in preventing the electroless nickel plating film from being oxidized in the water washing step before and after the heat treatment.
In addition, as a method for enhancing the reaction activity of the electroless nickel plating film to the electroless copper plating reaction, there is a method in which gold or palladium is substituted and deposited on the electroless nickel plating film. There was a problem of causing a significant increase in
The present invention has been made in view of the above situation, and has good adhesion to a substrate and a wiring substrate provided with electric wiring having low resistance, and good adhesion to an electric wiring formed article. And it aims at providing the formation method of the electrical wiring which can form an electrical wiring simply.

In order to achieve such an object, according to the present invention, there is provided a wiring board having a desired electrical wiring on a substrate, wherein the electrical wiring has an electroless nickel content within a range of 0.1 to 20% by weight of cobalt. -It was set as the structure which was the laminated structure which laminated | stacked the 1st layer which consists of a cobalt- phosphorus plating film | membrane and the 2nd layer which consists of an electroless copper plating film | membrane from the board | substrate side in this order.
As a preferred embodiment of the present invention, the electroless copper plating film has a thickness in the range of 0.1 to 2.0 μm.
As a preferred embodiment of the present invention, a configuration in which an electroless nickel plating film is provided on the electroless copper plating film as the second layer, and a substitution gold plating film is provided on the electroless nickel plating film. The configuration was

As a preferred aspect of the present invention, a configuration is adopted in which a substituted tin plating film is provided on the electroless copper plating film as the second layer.
As a preferred embodiment of the present invention, a configuration is adopted in which a substitution silver plating film is provided on the electroless copper plating film as the second layer.
The present invention relates to a method for forming an electrical wiring by an electroless plating method, wherein an electroless nickel-cobalt-phosphorous plating film having a cobalt content within a range of 0.1 to 20% by weight is formed on an electrical wiring formed object. A step of forming an electrode wiring pattern shape as a first layer, a step of applying a heat treatment for adhesion enhancement to the electroless nickel-cobalt-phosphorous plating film, and electroless formation on the electroless nickel-cobalt-phosphorous plating film And a step of forming a copper plating film as the second layer.
As a preferred embodiment of the present invention, the heat treatment is performed at 150 to 290 ° C. for 20 to 50 minutes.

According to the present invention, the first layer constituting the electrical wiring of the laminated structure on the substrate is an electroless nickel-cobalt-phosphorus plating film having a cobalt content in the range of 0.1 to 20% by weight. Since the adhesion to the substrate is extremely high and the second layer is an electroless copper plating film, the electrical resistance of the electrical wiring is sufficiently low.
In the present invention, since the electroless nickel-cobalt-phosphorous plating film having a cobalt content in the range of 0.1 to 20% by weight is formed as the first layer on the electrical wiring formed article, the post-process In the heat treatment for enhancing adhesion and the water washing step performed in step 1, the first layer is prevented from being oxidized, and the first layer exhibits sufficient catalytic activity to cause an electroless copper plating reaction. An electroless copper plating film can be formed as a second layer in a good state on the layer, and an electric wiring having a laminated structure can be formed.

Next, an optimal embodiment of the present invention will be described.
[Wiring board]
First, the wiring board of the present invention will be described.
FIG. 1 is a cross-sectional view for explaining a configuration example of a wiring board according to the present invention. In FIG. 1, a wiring board 1 is provided with electrical wiring 3 on one surface of a board 2 in a desired pattern. The electrical wiring 3 has a laminated structure in which a first layer made of an electroless nickel-cobalt-phosphorous plating film 4 and a second layer made of an electroless copper plating film 5 are laminated from the substrate 2 side.

The electroless nickel-cobalt-phosphorus plating film 4 as the first layer is a thin film having a cobalt content in the range of 0.1 to 20% by weight, preferably 0.5 to 10% by weight. On the other hand, it shows high adhesion strength. If the cobalt content is less than 0.1% by weight, formation of the electroless copper plating film 5 as the second layer becomes difficult, which is not preferable. On the other hand, when the cobalt content exceeds 20% by weight, the adhesion strength with the substrate 2 is insufficient, and the electric wiring 3 may be peeled off from the substrate 2 and is not preferable. Such an electroless nickel-cobalt-phosphorus plating film 4 has a thickness of 0.1 to 2.0 μm, preferably about 0.2 to 0.5 μm.
The second layer of electroless copper plating layer 5 constituting the electric wiring has a thickness of 0.1 to 2.0 μm, preferably about 0.2 to 0.5 μm.

The wiring board 1 of the present invention as described above is an electroless nickel-cobalt-phosphorous plating film 4 in which the first layer has extremely high adhesion to the substrate 2 and has catalytic activity for the electroless copper plating reaction. Since the second layer is the electroless copper plating film 5, the electrical resistance of the electrical wiring 3 is sufficiently low, and the adhesion of the electrical wiring 3 to the substrate 2 is good.
The substrate 2 constituting the wiring board may be, for example, a silicon substrate, a glass substrate, a resin substrate, a substrate obtained by patterning a transparent conductive film such as indium tin oxide (ITO) on these substrates, and the thickness thereof. Can be appropriately set according to the use of the wiring board 1.

The wiring board of the present invention is not limited to the above-described embodiment, and may be, for example, a multilayer structure in which another layer is further provided on the electroless copper plating film 5 as the second layer. As such an example, an electroless nickel plating film can be provided for the purpose of preventing oxidation of the electroless copper plating film 5. The electroless nickel plating film can have a thickness of about 0.1 to 0.2 μm. Furthermore, a displacement gold plating film may be provided on the electroless nickel plating film with a thickness of about 0.03 to 0.05 μm for the purpose of improving solder wettability. Further, for the purpose of preventing oxidation of electroless copper plating film 5 and improving solder wettability, a substituted tin plating film may be provided with a thickness of about 0.1 to 1.0 μm, or a substituted silver plating film may be provided. You may provide by the thickness of about 0.1-0.2 micrometer.
The wiring board of the present invention as described above includes, for example, flat displays such as a liquid crystal display (LCD), a plasma display (PDP), an electrochromic display (ECD), an electroluminescent display (FLD), and the like. It can be used for an electric circuit board.

[Method of forming electrical wiring]
Next, the method for forming electrical wiring according to the present invention will be described.
The electrical wiring forming method of the present invention utilizes an electroless plating method, and FIG. 2 is a process diagram showing an example of the present invention.

  In FIG. 2, first, an electroless nickel-cobalt-phosphorous plating film 14 'is formed as a first layer in the shape of an electrode wiring pattern on the electrical wiring forming object 11 (FIG. 2A). The electroless nickel-cobalt-phosphorus plating film 14 'can be formed using hypophosphorous acid, sodium hypophosphite, nickel hypophosphite or the like as a reducing agent. In order to make the electroless nickel-cobalt-phosphorous plating film 14 'into a desired pattern, a resist is formed on the electroless nickel-cobalt-phosphorous plating film 14' in a reverse pattern, and a stripping solution, for example, The exposed electroless nickel-cobalt-phosphorus plating film 14 'is dissolved and removed using a stripping solution for nickel plating film (Meltex MN-958, etc. manufactured by Meltex Co., Ltd.), and then the resist is stripped. The method of doing is mentioned.

  In the electroless nickel-cobalt-phosphorus plating film 14 ′ to be formed, the cobalt content is 0.1 to 20% by weight, preferably 0.5 to 10% by weight, and the thickness is 0.1 to 2%. It can be in the range of 0 μm, preferably 0.2 to 0.5 μm. When the cobalt content is less than 0.1% by weight, the electroless nickel-cobalt-phosphorous plating film 14 'is oxidized in the heat treatment in the next step, and the catalytic ability of the electroless copper plating reaction is reduced. It is not preferable. Moreover, when cobalt content exceeds 20 weight%, the adhesive strength with the electrical wiring formed object 11 board | substrate 2 will be inadequate, and the electroless nickel-cobalt-phosphorus plating film 14 will be mentioned during the electroless copper plating process mentioned later. Swelling may occur, which is not preferable.

The electrical wiring formation 11 may be a silicon substrate, a glass substrate, a resin substrate, a substrate obtained by patterning a transparent conductive film such as ITO on these substrates, and the like. It can be determined appropriately according to the use of the formed article 11.
As the next step, the electroless nickel-cobalt-phosphorous plating film 14 ′ is subjected to a heat treatment for improving the adhesion to the electrical wiring formed object 11, so that the electroless nickel-cobalt-phosphorous plating film 14 and (FIG. 2B). In the electroless nickel-cobalt-phosphorus plating film 14 obtained by this heat treatment, the hydrogen eutectoid in the coating during the plating reaction is removed, and the adhesion to the electrical wiring formed object 11 becomes high. The heat treatment can be performed, for example, in the range of 150 to 290 ° C. and 20 to 50 minutes. In this heat treatment, the electroless nickel-cobalt-phosphorous plating film 14 ′ prevents nickel from being oxidized by the action of cobalt contained therein. The

Next, an electroless copper plating film 15 is formed as a second layer on the electroless nickel-cobalt-phosphorus plating film 14 to form an electric wiring 13 having a laminated structure (FIG. 2C). The electroless copper plating film 15 is formed by using nickel of the electroless nickel-cobalt-phosphorous plating film 14 as a catalyst, and as a reducing agent, hypophosphorous acid, sodium hypophosphite, nickel hypophosphite, etc. Can be used. As described above, since the electroless nickel-cobalt-phosphorous plating film 14 'is prevented from being oxidized in the heat treatment step, the electroless nickel-cobalt-phosphorous plating film 14 has sufficient catalytic ability. The thickness of the electroless copper plating layer 15 can be in the range of 0.1 to 2.0 μm, preferably 0.2 to 0.5 μm.
Such a method for forming electrical wiring according to the present invention includes flat displays such as a liquid crystal display (LCD), a plasma display (PDP), an electrochromic display (ECD), and an electroluminescent display (FLD). It can be used for forming electric wiring on an electric circuit board.

Next, an Example is shown and this invention is demonstrated further in detail.
[Example 1]
A soda glass substrate for a liquid crystal display device was subjected to the following pretreatment.
<Degreasing treatment>
It was immersed for 10 minutes in a degreasing solution (liquid temperature 60 ° C.) containing Melg Cleaner ITO-170 manufactured by Meltex Co., Ltd. in pure water at 15 g / L. In addition, ultrasonic cleaning was used in combination.
<Degreasing treatment>
After the degreasing treatment, the glass substrate washed with water was immersed in a degreasing solution (liquid temperature 60 ° C.) containing 75 g / L of potassium hydroxide in pure water for 10 minutes. In this case, ultrasonic cleaning was also used.

<Etching treatment>
Meltex ITO-conditioner 480A manufactured by Meltex Co., Ltd. 20 g / L, Melplate ITO-conditioner 480B manufactured by Meltex Co., Ltd. 200 mL / L, respectively, in an etching solution (liquid temperature 25 ° C.) contained in pure water. The glass substrate subjected to the above degreasing treatment and washed with water was immersed for 10 minutes.
<Conditioning process>
The glass substrate subjected to the above etching treatment and washed with water was immersed for 5 minutes in a solution (solution temperature 25 ° C.) containing Melplate Conditioner 1101 manufactured by Meltex Co., Ltd. in pure water at 10 mL / L.

<Catalyst application>
Melt plate manufactured by Meltex Co., Ltd. Activator 7331 30 mL / L, 0.1 mol / L potassium hydroxide solution 1.5 mL / L, each containing a catalyst application liquid (liquid temperature 25 ° C., pH 6 0.0), the glass substrate subjected to the above conditioning treatment and washed with water was immersed for 5 minutes.
<Post-activator processing>
The glass substrate subjected to the above-mentioned catalyst application and washed with water was immersed for 5 minutes in a solution (liquid temperature 25 ° C.) containing Melplate PA7340 manufactured by Meltex Co., Ltd. in 10 mL / L pure water.

The glass substrate subjected to the pretreatment as described above is immersed in an electroless nickel plating solution (solution temperature: 70 ° C., pH 4.5) having the following composition for 5 minutes to form an electroless nickel-cobalt-phosphorus plating film (thickness 0). .3 μm) was formed.
(Composition of electroless nickel plating solution)
・ Nickel sulfate 0.1 mol / L
・ Cobalt sulfate: 0.1 mol / L
・ Sodium hypophosphite: 0.3 mol / L
・ Malic acid: 0.1 mol / L
・ Succinic acid: 0.1 mol / L
・ Lead: 0.5mg / L
・ Sodium thiosulfate: 1mg / L

The composition of the electroless nickel-cobalt-phosphorus plating film was analyzed by an inductively coupled plasma emission spectrometer (ICP-AES). As a result, the cobalt content was 0.8% by weight and the phosphorus content was 10.5% by weight. Met.
Next, the electroless nickel-cobalt-phosphorus plating film on the glass substrate was subjected to heat treatment at 260 ° C. for 30 minutes. About the electroless nickel-cobalt-phosphorus plating film before and after this heat treatment, a tape peeling test after cross-cutting was performed under the following conditions. As a result, all of the plating film was peeled off before the heat treatment, but peeling of the plating film was not observed after the heat treatment, and high adhesion to the glass substrate was imparted to the electroless nickel-cobalt-phosphorous plating film by the heat treatment. It was confirmed.
(Conditions for tape peel test after cross-cutting)
According to JIS K 5400, the clearance interval was set to 2 mm, a grid-like cut was made (number of squares: 25), and evaluation was performed by a grid tape method (8.5.2).

Next, the electroless nickel-cobalt-phosphorous plating film after the heat treatment is immersed in an electroless copper plating solution (Melplate CU-5100 manufactured by Meltex Co., Ltd., liquid temperature 50 ° C.) (10 minutes), and electroless An electroless copper plating film (thickness 0.3 μm) was formed on the nickel-cobalt-phosphorus plating film.
As a result of measuring the specific resistance of the metal film having the two-layer structure formed as described above with a four-point probe resistivity meter (MCP-T350 manufactured by Mitsubishi Chemical Corporation), it is 2.7 μΩcm and the resistance is extremely low. Was confirmed. Further, in the above electroless copper plating step, no peeling of the electroless nickel-cobalt-phosphorous plating film from the glass substrate was observed.

[Example 2]
The electroless nickel plating solution used in Example 1 was the same as in Example 1 except that the electroless nickel plating solution having a composition of 0.2 mol / L of cobalt sulfate was used. The formation of the phosphor plating film was performed. As a result of analyzing the composition of the electroless nickel-cobalt-phosphorous plating film in the same manner as in Example 1, the cobalt content was 2.5% by weight and the phosphorus content was 10.8% by weight.
Next, the electroless nickel-cobalt-phosphorous plating film was subjected to heat treatment under the same conditions as in Example 1, and then electroless copper plating was performed under the same conditions as in Example 1.
The specific resistance of the metal film having a two-layer structure formed as described above was measured in the same manner as in Example 1. As a result, it was 2.5 μΩcm, and it was confirmed that the resistance was extremely low. Further, in the above electroless copper plating step, no peeling of the electroless nickel-cobalt-phosphorous plating film from the glass substrate was observed.

[Example 3]
The electroless nickel plating solution used in Example 1 was the same as Example 1 except that the electroless nickel plating solution having a composition of 0.3 mol / L cobalt sulfate and a bath pH of 6.5 was used. Then, the electroless nickel-cobalt-phosphorus plating film was formed. As a result of analyzing the composition of this electroless nickel-cobalt-phosphorous plating film in the same manner as in Example 1, the cobalt content was 20% by weight and the phosphorus content was 8.5% by weight.
Next, the electroless nickel-cobalt-phosphorous plating film was subjected to heat treatment under the same conditions as in Example 1, and then electroless copper plating was performed under the same conditions as in Example 1.
The specific resistance of the metal film having a two-layer structure formed as described above was measured in the same manner as in Example 1. As a result, it was 2.5 μΩcm, and it was confirmed that the resistance was extremely low. Further, in the above electroless copper plating step, no peeling of the electroless nickel-cobalt-phosphorous plating film from the glass substrate was observed.

[Comparative Example 1]
In the same manner as in Example 1 except that an electroless nickel plating solution having a composition obtained by removing cobalt sulfate from the composition of the electroless nickel plating solution used in Example 1 was used, until the formation of the electroless nickel-phosphorous plating film. Went. As a result of analyzing the composition of this electroless nickel-phosphorous plating film in the same manner as in Example 1, the phosphorus content was 8.0% by weight.
Next, the electroless nickel-phosphorous plating film was subjected to heat treatment under the same conditions as in Example 1, and then electroless copper plating was performed under the same conditions as in Example 1. However, the electroless copper plating reaction did not start on the electroless nickel-phosphorous plating film, and the electroless copper plating film could not be formed.

[Comparative Example 2]
The electroless nickel plating solution used in Example 1 was the same as in Example 1 except that the electroless nickel plating solution having a composition of 0.003 mol / L of cobalt sulfate was used. The formation of the phosphor plating film was performed. As a result of analyzing the composition of this electroless nickel-cobalt-phosphorus plating film in the same manner as in Example 1, the cobalt content was 0.05% by weight and the phosphorus content was 10.4% by weight.
Next, the electroless nickel-cobalt-phosphorous plating film was subjected to heat treatment under the same conditions as in Example 1, and then electroless copper plating was performed under the same conditions as in Example 1. However, the electroless copper plating reaction did not start on the electroless nickel-cobalt-phosphorous plating film, and the electroless copper plating film could not be formed.

[Comparative Example 3]
The electroless nickel plating solution used in Example 1 was the same as in Example 1 except that the electroless nickel plating solution having a composition of 0.3 mol / L cobalt sulfate and a bath pH of 7.0 was used. Then, the electroless nickel-cobalt-phosphorus plating film was formed. As a result of analyzing the composition of the electroless nickel-cobalt-phosphorus plating film in the same manner as in Example 1, the cobalt content was 25% by weight and the phosphorus content was 8.2% by weight.
Next, the electroless nickel-cobalt-phosphorous plating film was subjected to heat treatment under the same conditions as in Example 1, and then electroless copper plating was performed under the same conditions as in Example 1. However, in the electroless copper plating process, peeling of the electroless nickel-cobalt-phosphorous plating film from the glass substrate occurs, and an electroless copper plating film may be formed on the electroless nickel-cobalt-phosphorous plating film. could not.

[Comparative Example 4]
In the same manner as in Example 1, the electroless nickel-cobalt-phosphorus plating film was formed.
Next, electroless copper plating was performed under the same conditions as in Example 1 without subjecting the electroless nickel-cobalt-phosphorous plating film to heat treatment. However, in the electroless copper plating process, peeling of the electroless nickel-cobalt-phosphorous plating film from the glass substrate occurs, and an electroless copper plating film may be formed on the electroless nickel-cobalt-phosphorous plating film. could not.

  It is useful for manufacturing various flat displays, various electric circuit boards, electronic devices and the like.

It is sectional drawing for demonstrating the structural example of the wiring board of this invention. It is process drawing which shows an example of the formation method of the electrical wiring of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 2 ... Board 3 ... Electric wiring 4 ... Electroless nickel-cobalt-phosphorus plating film (first layer)
5. Electroless copper plating film (second layer)
DESCRIPTION OF SYMBOLS 11 ... Electric wiring formation 13 ... Electric wiring 14 ... Electroless nickel-cobalt-phosphorus plating film (1st layer)
14 '... electroless nickel-cobalt-phosphorus plating film before heat treatment 15 ... electroless copper plating film (second layer)

Claims (8)

In a wiring board having desired electrical wiring on the board,
The electrical wiring includes a first layer made of an electroless nickel-cobalt-phosphorous plating film having a cobalt content in the range of 0.1 to 20% by weight, and a second layer made of an electroless copper plating film. A wiring board having a laminated structure in which the substrates are laminated in order.   The wiring board according to claim 1, wherein the electroless copper plating film as the second layer has a thickness in a range of 0.1 to 2.0 μm.   The wiring board according to claim 1, further comprising an electroless nickel plating film on the electroless copper plating film as the second layer.   The wiring board according to claim 3, further comprising a displacement gold plating film on the electroless nickel plating film.   The wiring board according to claim 1, further comprising a substitution tin plating film on the electroless copper plating film as the second layer.   The wiring board according to claim 1, further comprising a substitution silver plating film on the electroless copper plating film as the second layer. In the method of forming electrical wiring by electroless plating,
Forming an electroless nickel-cobalt-phosphorous plating film having a cobalt content in the range of 0.1 to 20% by weight as an electrode wiring pattern shape as a first layer on the electrical wiring formation;
Applying a heat treatment for adhesion enhancement to the electroless nickel-cobalt-phosphorus plating film;
Forming an electroless copper plating film as a second layer on the electroless nickel-cobalt-phosphorous plating film.   The said heat processing is performed in 150-290 degreeC and the range for 20-50 minutes, The formation method of the electrical wiring of Claim 7 characterized by the above-mentioned.

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