JPH07235752A - Method for removing chlolrine ion from etching solution and wiring board producing methods using this solution - Google Patents

Abstract

PURPOSE:To provide a method for removing chlorine ions from an etching solution of nickel or nickel alloy by a simple method and a wiring board producing method using an etching solution from which chlorine ions wire removed by using the chlorine ion removing method. CONSTITUTION:Copper is contacted to an etching solution of nickel and/or nickel alloy containing an organic acid containing carboxyl group as an additive agent and containing a heterocyclic compound including nitrogen atoms in the form of -NH- or =N- as ring members in an acidic solution having nitric acid and hydrogen peroxide as principal component. And wiring boards are produced by using this method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing chloride ions in a solution for etching nickel or a nickel alloy and a method for using the etching solution.

[0002]

2. Description of the Related Art Printed wiring boards are required to have high wiring density with the development of electronic equipment, and miniaturization of wiring is one of the major technical problems. As a method for manufacturing such a printed wiring board, a copper-clad laminate obtained by bonding a copper foil to an insulating base material is used as a starting material, and a portion of the copper foil that does not become a circuit conductor is removed by etching to form a circuit. In general, the active method, the additive method of forming a circuit by electroless plating to the required circuit shape on the surface of the insulating base material, the partial additive method of forming a part of the circuit conductor such as the inner wall of the through hole by electroless plating, etc. Known to be.

Above all, the subtractive method has been used for a long time, and in order to improve the wiring density, it is usually performed to reduce the thickness of the copper foil of the copper-clad laminate. The reason for this is to form an etching resist in the required circuit shape on the surface of the copper foil, and a phenomenon called so-called side etching in which copper is corroded from the side surface of the unnecessary circuit portion exposed from the etching resist with the etching solution, This is because the thicker the copper foil is, the more copper is removed from the side surface by the side etching, which makes it difficult to form a fine circuit.

As the etching resist of the subtract method, there is a solder stripping method using solder. The solder is removed after the wiring is formed.
Japanese Patent No. 8280 discloses a mixture of nitric acid and hydrogen peroxide containing iron ions and hydroxycarboxylic acid as main components. Further, as a copper foil for a circuit board with a resistor, a copper foil having nickel or a nickel-phosphorus alloy plated on the copper foil is disclosed in US Pat. No. 3,808,576.

Further, a first copper layer 1, an intermediate layer 2 made of a metal having a high corrosion resistance to a solution that corrodes copper, and a second copper layer
Also a copper foil for a printed wiring board having a three-layer structure in which the intermediate layer 2 is sandwiched between the first copper layer 1 and the second copper layer 3 of JP-A-58-108785. It is known from the publication. Nickel, nickel-iron, and nickel-tin alloy are used for the intermediate layer 2, and the stripping method is the same as the method of electrolytic stripping by dipping in an acidic aqueous solution containing sulfuric acid and m-nitrobenzenesulfonic acid. Known from the gazette. When a composite metal foil having a three-layer structure is used for a printed wiring board, an insulating base material is joined to the second copper layer, the first copper layer is selectively removed, and the intermediate layer 2 is further removed to form a copper-clad film. Although it is used as a laminated plate, in order to remove nickel, nickel-iron, and nickel-tin used in the intermediate layer 2 at this time, an acidic aqueous solution containing sulfuric acid and m-nitrobenzenesulfonic acid disclosed in the publication is used. It must be soaked in and electrolytically peeled off, which is troublesome.

Further, commercially available etching solutions for nickel or nickel alloys include alkaline Enstrip NP (trade name, manufactured by Meltex) and Metec SCB.
(McDermid, product name), Top Lip AZ
(Okuno Pharmaceutical Co., Ltd., product name) and the like, and a method of peeling by immersing in a solution, acidic Melstrip N-950 (Meltex company, product name), Melstrip HN-841 (Meltex company, product name) ) Etc. are known and the method of peeling is known.

However, when the liquid Enstrip NP (manufactured by Meltex, trade name) which is chemically removed is used, an altered layer called smut, which is an undissolved residue of the intermediate layer, is formed, and this smut Is difficult to remove.
When Metec SCB (trade name, manufactured by McDermid, Inc.) is used, the copper layer of the substrate may be dissolved, and if the copper layer is to be left completely, part of the nickel alloy remains.
In the former case, the copper layer becomes discontinuous, and in the latter case, the adhesiveness deteriorates. Furthermore, when Top Lip AZ (trade name, manufactured by Okuno Seiyaku Co., Ltd.) was used, the dissolution rate was very slow and not practical. Melstrip N-950
(Meltex, product name) and Melstrip HN-
When 841 (trade name, manufactured by Meltex Co.) was used, there was a drawback that a black film was formed when the nickel-phosphorus alloy was peeled off and copper was excessively etched.

In order to solve such a problem, the present inventors have added an acidic solution containing nitric acid and hydrogen peroxide as main components to an organic acid containing a carboxyl group as an additive and -NH as a ring member. An etching solution containing a heterocyclic compound containing a nitrogen atom in the form of-or = N- has been developed.

[0009]

By the way, this etching solution has a new problem that the etching property of nickel or nickel alloy is deteriorated and nickel or nickel alloy residue is generated. As a result of diligent studies by the present inventors, this decrease in etching property was caused by chlorine ions of 30 pp.
It was discovered that this occurs due to mixing of m or more.

The present invention provides a method for removing chlorine ions from a nickel or nickel alloy etching solution by a simple method and a method for producing a wiring board using the etching solution from which chlorine ions have been removed by using this method. The purpose is.

[0011]

The method for removing chlorine ions in an etching solution of the present invention comprises: an acidic solution containing nitric acid and hydrogen peroxide as main components; and an organic acid containing a carboxyl group as an additive, A heterocyclic compound containing a nitrogen atom in the form of -NH- or = N- as a ring member,
It is characterized in that copper is brought into contact with an etching solution of nickel and / or a nickel alloy.

Here, nitric acid is used to maintain the acidity necessary for stripping nickel, and the amount used is 100 to 100.
It is 300 g / l. The concentration of nitric acid is 100-300g /
When the amount is less than 100 g / l, the peeling action is weak, and when the amount is more than 300 g / l, the acidity is too strong and excessive etching may occur when the copper layer is used as the substrate.

Further, hydrogen peroxide acts as an oxidant,
It oxidizes nickel to promote the exfoliation of nickel, and the amount used is preferably 5 to 20 ml / l. The reason is that if it is less than 5 ml / l, the effect as an oxidant is not sufficient, and if it exceeds 20 ml / l, the oxidizing effect is too strong, and the copper layer of the substrate may be excessively etched.

The organic acid having a carboxyl group as the first additive component in the present invention has an acid strength Ka of 10
^-3 to 10 ^-5 are preferable, and examples thereof include formic acid, acetic acid, propionic acid, butyric acid, succinic acid, glutaric acid, lactic acid, malic acid, citric acid, tartaric acid, and derivatives thereof. Such an organic acid is preferably used in an amount effective to sufficiently suppress the dissolution of the copper substrate when the nickel alloy layer is peeled off. This organic acid is preferably 10 to 200 g / l in the stripping solution. Organic acid concentration of 10
The reason for setting it to 200 g / l is that if it is less than 10 g / l, the corrosion inhibiting effect on the copper layer of the substrate is small, and if it exceeds 200 g / l, no further effect can be expected and it is uneconomical in practice. . Therefore, the concentration of the organic acid is 10 to 20.
0 g / l is preferred.

The second additive component of the present invention is a heterocyclic compound containing a nitrogen atom in the form of -NH- or = N- as a ring member, which is soluble in an acidic solution. And include triazoles and their derivatives. The addition amount of triazole or its derivative is 1 to 10 g.
/ L is preferred. The amount of triazole or its derivative added is set to 1 to 10 g / l because the effect of inhibiting the corrosion of the copper layer of the substrate is small when the amount is less than 1 g / l, and the effect is expected to be higher when the amount exceeds 10 g / l. This is because it cannot be done and it is uneconomical in practice. Therefore, the addition amount of triazole or its derivative is preferably 1 to 10 g / l.

The copper used in the present invention may be any metallic copper, such as copper plate, copper particles, copper powder, copper filter, MCL, etc., and chlorine ions are removed by bringing them into contact with an etching solution. Any method may be used as the contacting method as long as chlorine ions can be removed, such as immersion and spraying.

A wiring board can be manufactured by the following steps using such a method of removing chlorine ions from the etching solution. A. Step of forming plating resist on copper surface of copper-clad laminate in which copper foil is laminated on insulating substrate surface B. Step of plating nickel or nickel alloy on the exposed portion, removing the plating resist, and etching away only the exposed copper foil C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing nickel or nickel alloy by bringing the substrate into contact with the etching solution from which the chlorine ions have been removed

The following steps can also be performed. A. Make a hole in the copper-clad laminate, which is a copper foil laminated to the surface of the insulating substrate, and perform electroless copper plating on the inner wall of the hole and the copper foil surface.
Step of forming plating resist on the copper surface B. Step of plating nickel or nickel alloy on the exposed portion, removing the plating resist, and etching away only the exposed copper foil C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. A step of etching and removing only nickel or nickel alloy by bringing the substrate into contact with the etching solution from which the chlorine ions have been removed

Further, the following steps can be performed. A. On the surface of the insulating substrate, the first copper layer and 0.04 ~ 1.5μ
m. Nickel or nickel alloy layer and the metal foil having the second copper layer are laminated and integrated by heating and pressing so that the first copper layer is in contact with the insulating substrate. Step of etching away only the second copper layer of the laminate C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing only nickel or nickel alloy by bringing the laminate into contact with the etching solution from which chlorine ions have been removed E. Step of making a hole in the laminated plate and performing electroless plating on the inner wall of the hole and the entire exposed copper surface, and further performing electrolytic plating if necessary to secure a necessary thickness as a circuit conductor F. Form the etching resist into the required circuit shape,
Process to remove exposed copper by etching

Furthermore, the following steps can be carried out. A. On the surface of the insulating substrate, the first copper layer and 0.04 ~ 1.5μ
m. Nickel or nickel alloy layer and the metal foil having the second copper layer are laminated and integrated by heating and pressing so that the first copper layer is in contact with the insulating substrate. Step of etching and punching only the second copper layer of the laminate C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing only nickel or a nickel alloy by bringing the substrate into contact with the etching solution from which chlorine ions have been removed. Step of performing electroless plating on the inner wall of the hole and the entire exposed copper surface, and further electrolytic plating if necessary to secure a necessary thickness as a circuit conductor F. Form the etching resist into the required circuit shape,
Process to remove exposed copper by etching

[0021]

The main components of the etching solution used in the present invention are nitric acid and hydrogen peroxide, and it is considered that the dissolution of nickel proceeds by the following reaction. Ni + H ₂ O ₂ → NiO + H ₂ O (1) NiO + 2HNO ₃ → Ni (NO ₃ ) ₂ + H ₂ O (2) It is also believed that copper reacts and dissolves in the same manner. Cu + H ₂ O ₂ → CuO + H ₂ O (3) CuO + 2HNO ₃ → Cu (NO ₃ ) ₂ + H ₂ O (4) Here, when chlorine ions are present in the etching solution,
It is considered that the reaction of the following formula (5) occurs, and since cuprous chloride has a low solubility, it is considered that the dissolution of nickel is hindered by being attached to the nickel surface. Cu + Cu (NO ₃ ) ₂ + 2Cl ⁻ → 2CuCl + 2NO ₃ ⁻ (5) The chlorine ion removal method used in the present invention is carried out by adding an organic acid containing a carboxyl group as an additive to an acidic solution containing nitric acid and hydrogen peroxide as main components. And a heterocyclic compound containing a nitrogen atom in the form of -NH- or = N- as a ring member, the copper is brought into contact with an etching solution of nickel and / or a nickel alloy. It is considered that it is possible to generate cuprous chloride having a low solubility on the surface and remove chlorine ions.

[0022]

【Example】

Example 1 Table 1 shows the results of measuring the chlorine ion concentration and examining the selective etching property after performing a chlorine ion removal treatment using a liquid having the following composition as an etching liquid for nickel and / or a nickel alloy. . (Composition and conditions) Nitric acid 200 g / l Hydrogen peroxide water 10 ml / l Acetic acid 100 g / l Benzotriazole 5 g / l Chloride concentration 50 ppm Treatment temperature 50 ° C. Copper plate treatment amount 100 dm ² / l Treatment time 10 minutes

Example 2 As a nickel and / or nickel alloy etching solution, a solution having the following composition was used to remove chlorine ions, and then the results of measuring the chlorine ion concentration and examining the selective etching property are shown. Shown in 1. (Composition) Nitric acid 200 g / l Hydrogen peroxide water 10 ml / l Malic acid 100 g / l Bendtriazole 5 g / l Chloride ion concentration 100 ppm Treatment temperature 50 ° C. Copper particle treatment amount 100 dm ² / l Treatment time 10 minutes

Example 3 As a nickel and / or nickel alloy etching solution, a solution having the following composition was used to remove chlorine ions, and then the results of measuring the chlorine ion concentration and examining the selective etching property are shown. Shown in 1. (Composition) Nitric acid 200 g / l Hydrogen peroxide water 10 ml / l Citric acid 100 g / l Bendtriazole 5 g / l Chloride ion concentration 50 ppm Treatment temperature 50 ° C. Copper filter treatment amount 100 dm ² / l Treatment time 10 minutes

COMPARATIVE EXAMPLE 1 As a nickel and / or nickel alloy etching solution, a solution having the following composition was used to remove chlorine ions, and then the chlorine ion concentration was measured and the selective etching property was investigated. Shown in 1. (Composition) Nitric acid 200 g / l Hydrogen peroxide water 10 ml / l Acetic acid 100 g / l Bend triazole 5 g / l Chloride concentration 50 ppm Treatment temperature 50 ° C.

COMPARATIVE EXAMPLE 2 As a nickel and / or nickel alloy etching solution, a solution having the following composition was used to remove chlorine ions, and then the chlorine ion concentration was measured and the selective etching property was investigated. Shown in 1. (Composition) Nitric acid 200 g / l Hydrogen peroxide water 10 ml / l Malic acid 100 g / l Bend triazole 5 g / l Chloride ion concentration 100 ppm Treatment temperature 50 ° C.

(Test) (1) Adjustment of Material As a sample having nickel and nickel-phosphorus alloy layers, about 0 × 50 mm of epoxy copper-clad laminate board was coated with the following nickel-phosphorus alloy plating solution and conditions. .2μ
m of nickel-phosphorus alloy was plated. The film thickness of nickel and nickel-phosphorus alloy is fluorescent X
Linear film thickness meter SFT-8000 (manufactured by Seiko Instruments Inc.,
(Trade name) was used for measurement. (Composition of nickel plating solution) Nickel sulfate 240 g / l Nickel chloride 45 g / l Boric acid 30 g / l (Plating conditions) Temperature 35 ° C Current density 1.5 A / dm ² hours 4 minutes (Composition of nickel-phosphorus plating solution) Nickel sulfate 240 g / l Nickel chloride 45 g / l Boric acid 30 g / l Phosphorous acid 5 g / l (plating conditions) Temperature 35 ° C. Current density 1.5 A / dm ² hours 4 minutes

(2) Selective Etching Property Test The above MCL was dipped in an etching solution with and without chlorine ion removal treatment to etch the nickel-phosphorus alloy of each sample and to reduce the thickness of the base copper foil. I checked.
The fluorescent X-ray film thickness meter was used to measure the film thickness. The case where the nickel-phosphorus alloy could be selectively etched was evaluated as ◯, and the case where the etching residue was generated was evaluated as x.

[0029]

[Table 1]

Example 4 A plating resist was formed on the copper foil surface of MCL-E-67 (Hitachi Chemical Co., Ltd., trade name), which is a copper-clad laminate obtained by laminating a copper foil on the surface of an epoxy resin insulating substrate. ,
Nickel plating is performed on the exposed portion to remove the plating resist, and then only the exposed copper foil is removed by etching with an alkaline etchant, and the etching solution used in Example 1 is contacted to remove only nickel. However, it was a single-sided circuit board.

Example 5 MCL-E-67 (Hitachi Chemical Co., Ltd., trade name), which is a copper-clad laminate in which a copper foil is laminated on the surface of an epoxy resin insulating substrate, is drilled to form an inner wall of the hole and copper. Electroless plating is performed on the foil surface, a plating resist is formed on the copper surface, the nickel-phosphorus alloy plating is performed, and after removing the plating resist, only the exposed copper foil is removed by etching with an alkaline etchant. Only nickel-phosphorus was removed by etching by bringing it into contact with the etching solution of No. 2 to obtain a double-sided circuit board.

Example 6 A copper-clad laminate MCL-E-67 (Hitachi Chemical Co., Ltd., trade name) in which a copper foil is laminated on the surface of an epoxy resin insulating substrate is processed into an inner layer circuit, and prepreg E
-67 (Hitachi Chemical Co., Ltd., trade name), 35 μm
After making a hole in the laminated plate laminated with a copper foil of thickness, electroless plating is performed on the inner wall of the hole and the surface of the copper foil, a plating resist is formed on the copper surface, the nickel plating is performed, and after removing the plating resist Then, only the exposed copper foil was removed by etching with an alkaline etchant, and by contacting it with the etching solution of Example 3, only nickel was removed by etching to obtain a multilayer circuit board.

Example 7 Insulating substrate prepreg E-67 (Hitachi Chemical Co., Ltd.,
0.04 to 1.5 μm nickel on the surface of the product name)
A metal foil having a phosphorus alloy layer and a copper layer having a thickness of 5 μm is superposed so that the copper layer contacts the insulating base material, heated and pressed to be laminated and integrated, and a hole is made in the laminated plate to bring it into contact with the etching solution of Example 1. By doing so, only the nickel-phosphorus alloy layer is removed by etching, electroless plating is performed on the entire inner wall of the hole and the exposed copper surface of the laminated plate by 20 μm to form an etching resist in a required circuit shape, and the exposed copper is etched. It was removed to obtain a double-sided circuit board.

Example 8 Insulating substrate prepreg E-67 (Hitachi Chemical Co., Ltd.,
The first copper layer of 1 to 15 μm and 0.0
A metal foil having a nickel-phosphorus alloy layer of 4 to 1.5 μm and a second copper layer is stacked so that the first copper layer is in contact with the insulating base material, and heated and pressed to be laminated and integrated to form a second copper layer. Only the layer is removed by etching with an alkaline etchant, and the nickel-phosphorus alloy layer is removed by etching by contacting it with the etching solution of Example 2, and a hole is made in the laminated plate and the inner wall of the hole of the laminated plate and the exposed copper. Electroless plating is performed on the entire surface, and further electrolytic plating is performed to secure 35 μm required as a circuit conductor, an etching resist is formed in a required circuit shape, and exposed copper is removed by etching.
It was a wiring board.

Example 9 MCL-E-67 (Hitachi Chemical Co., Ltd., trade name), which is a copper-clad laminate in which a copper foil is laminated on the surface of an epoxy resin insulating substrate, is processed into an inner layer circuit, and prepreg E
-67 (Hitachi Chemical Co., Ltd., trade name), 1-15
μm first copper layer and 0.04 to 1.5 μm nickel-
A metal foil having a phosphorus alloy layer and a second copper layer is stacked so that the first copper layer is in contact with the insulating base material, heated and pressed to be laminated and integrated, and only the second copper layer is removed by etching with an alkaline etchant. Then, only the nickel-phosphorus alloy layer is removed by etching by bringing it into contact with the etching solution of Example 3, and a hole is made in the laminated plate to perform electroless plating on the inner wall of the hole of the laminated plate and the entire exposed copper surface. Further, electrolytic plating was performed to secure 35 μm required as a circuit conductor, an etching resist was formed into a required circuit shape, and exposed copper was removed by etching to obtain a multilayer wiring board.

[0036]

According to the present invention, by contacting copper with an etching solution, chlorine ions contained in the etching solution can be removed and the etching property of nickel or nickel alloy can be improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location H05K 3/42 B 7511-4E (72) Inventor Nobuyuki Minami 1500 Ogawa Ogawa, Shimodate-shi, Ibaraki Hitachi Chemical Shimodate Factory of Industrial Co., Ltd.

Claims (7)

[Claims] 1. An acidic solution containing nitric acid and hydrogen peroxide as main components, which contains an organic acid containing a carboxyl group as an additive and a nitrogen atom in the form of —NH— or = N— as a ring member. The method for removing chlorine ions in an etching solution, which comprises contacting copper with an etching solution of nickel and / or a nickel alloy containing the heterocyclic compound. 2. The etching according to claim 1, wherein the heterocyclic compound containing a nitrogen atom in the form of —NH— or ═N— as a ring member is triazole or a derivative thereof. A method of removing chlorine ions in a liquid using copper. 3. The composition ratio of the etching liquid of nickel and / or nickel alloy is 10 to 30% by weight of nitric acid, 5 to 20 ml / l of 30% hydrogen peroxide solution, and 1 to 20 of organic acid containing a carboxyl group. % Of triazole or its derivative is 0.1 to 1% by weight, and a method for removing chlorine ions in an etching solution, characterized in that 4. A method for manufacturing a wiring board, comprising the following steps. A. Step of forming plating resist on copper surface of copper-clad laminate in which copper foil is laminated on insulating substrate surface B. Step of plating nickel or nickel alloy on the exposed portion, removing the plating resist, and etching away only the exposed copper foil C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing nickel or nickel alloy by bringing the substrate into contact with the etching solution from which the chlorine ions have been removed 5. A method of manufacturing a wiring board, comprising the following steps. A. Make a hole in the copper-clad laminate, which is a copper foil laminated to the surface of the insulating substrate, and perform electroless copper plating on the inner wall of the hole and the copper foil surface.
Step of forming plating resist on the copper surface B. Step of plating nickel or nickel alloy on the exposed portion, removing the plating resist, and etching away only the exposed copper foil C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. A step of etching and removing only nickel or nickel alloy by bringing the substrate into contact with the etching solution from which the chlorine ions have been removed 6. A method of manufacturing a wiring board, comprising the following steps. A. On the surface of the insulating substrate, the first copper layer and 0.04 ~ 1.5μ
m. Nickel or nickel alloy layer and the metal foil having the second copper layer are laminated and integrated by heating and pressing so that the first copper layer is in contact with the insulating substrate. Step of etching away only the second copper layer of the laminate C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing only nickel or nickel alloy by bringing the laminate into contact with the etching solution from which chlorine ions have been removed E. Step of making a hole in the laminated plate and performing electroless plating on the inner wall of the hole and the entire exposed copper surface, and further performing electrolytic plating if necessary to secure a necessary thickness as a circuit conductor F. Form the etching resist into the required circuit shape,
Process to remove exposed copper by etching 7. A method for manufacturing a wiring board, comprising the following steps. A. On the surface of the insulating substrate, the first copper layer and 0.04 ~ 1.5μ
m. Nickel or nickel alloy layer and the metal foil having the second copper layer are laminated and integrated by heating and pressing so that the first copper layer is in contact with the insulating substrate. Step of etching and punching only the second copper layer of the laminate C. A heterocyclic compound containing an acidic solution containing nitric acid and hydrogen peroxide as main components, an organic acid containing a carboxyl group as an additive, and a nitrogen atom in the form of -NH- or = N- as a ring member. Step of contacting copper with an etching solution containing and removing chlorine ions D. Step of etching and removing only nickel or a nickel alloy by bringing the substrate into contact with the etching solution from which chlorine ions have been removed. Step of performing electroless plating on the inner wall of the hole and the entire exposed copper surface, and further electrolytic plating if necessary to secure a necessary thickness as a circuit conductor F. Form the etching resist into the required circuit shape,
Process to remove exposed copper by etching