TWI519411B - Composite copper foil and its manufacturing method - Google Patents

Description

Composite copper foil and manufacturing method thereof

The present invention relates to a composite copper foil suitable for forming a circuit by etching and a method of manufacturing the same.

Copper foil for printed circuits is widely used in electronics. In the electrical equipment, the copper foil for a printed circuit is usually laminated on a substrate such as a synthetic resin sheet or a film at a high temperature and high pressure via an adhesive or without using an adhesive to produce a copper clad laminate, and thereafter, in order to form a desired circuit. The circuit is printed by a resist coating and exposure step, and an etching process for removing excess portions of the copper foil is performed, and further various components are soldered to form a printed circuit for an electronic device.

In recent years, the wiring density of printed wiring boards has become high, and the interval between connection terminals of electronic parts has become small. Therefore, it is inevitable to make the thickness of the copper foil of the copper clad laminate thin. Moreover, the multi-layer structure of the laminate is also a trend of the times, and the copper foil requires a composite copper foil such as a thick copper foil/barrier layer/thin copper foil. Of course, the copper foil which is the starting material for the production of the copper clad laminate having such a structure must have an important function.

A copper foil having a three-layer structure of a thick copper foil/nickel layer/thin copper foil is known as a material of a substrate (carrier), and a thick rolled copper foil or an electrolytic copper foil is used for the calendering. A thin nickel film is formed on the copper foil or the electrolytic copper foil, and a thin copper layer is formed on the nickel film (see Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5).

The copper foil with the carrier is formed by etching the thin copper layer As a basic material, the copper layer which is the base of the rolled copper foil or the electrolytic copper foil is finally removed by etching, and the nickel layer is also removed. Moreover, a circuit is formed on the side of the thin copper layer.

In this case, the base copper layer of the rolled copper foil or the electrolytic copper foil serves to facilitate the treatment of the thin copper foil for circuit formation, and the nickel layer functions as an intermediate layer, so that it is removed at the time of circuit formation.

Therefore, in the composite copper foil having a three-layer structure of a thick copper foil/nickel layer/thin copper foil having such a purpose, the adhesion between the nickel layer and the thin copper foil is not to be peeled off during the treatment. Just fine, not very important.

On the other hand, there is also a literature focusing on the adhesion between the copper layer and the nickel layer. Patent Document 6 proposes to improve the peeling resistance by setting the surface roughness of the copper layer in contact with the nickel layer as a specific condition.

An oxide film is slightly formed on the nickel layer. Therefore, when copper is plated on the nickel layer, even if the surface of the nickel layer is roughened by the adhesion of the copper layer formed thereon, This oxide film does not greatly improve the ease of peeling.

Further, it has been proposed to form a copper layer as a adhesion improving layer on a nickel layer, and to bond the copper layer to a thick copper foil (see Patent Document 4).

In addition, a clad material in which copper of nickel is rolled in the middle is proposed (see Patent Document 7 and Patent Document 8). However, when the plating step and the calendering step of different kinds of steps are combined, the manufacturing cost is increased, and such a mechanical method has a problem that it is difficult to obtain a laminated structure of copper having a uniform thickness and being as thin as possible. Also, in order to be calendered The surface of the copper foil which is in contact with the calender roll becomes smooth, and when it is necessary to adhere to the resin, it is necessary to carry out a roughening treatment.

In short, it is considered that the following problems have not been solved: the wiring density of printed wiring boards is now high, and it is required to reduce the interval between the connection terminals of electronic components, and to manufacture them at low cost.

Patent Document 1: Japanese Laid-Open Patent Publication No. SHO 58-108785

Patent Document 2: Japanese Patent No. 3683032

Patent Document 3: Japanese Patent No. 3543348

Patent Document 4: Japanese Laid-Open Patent Publication No. 2005-72425

Patent Document 5: Japanese Patent No. 4191977

Patent Document 6: Japanese Patent Laid-Open No. Hei 8-181432

Patent Document 7: International Publication WO00-05934

Patent Document 8: Japanese Patent No. 4195162

An object of the present invention is to provide a composite copper foil which is capable of improving the bonding strength between nickel and copper when a composite copper foil composed of copper/nickel/copper is formed, and which is suitable for forming an electric circuit by etching, and a method for producing the same.

The present inventors have obtained the knowledge that the disadvantages of the prior composite copper foil, that is, the insufficient bonding strength of nickel and copper, can be solved by designing the steps of copper plating and nickel plating, whereby the previous problems can be solved.

The present invention provides a basis based on this knowledge insight:

(1) A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or one side of the foil (A), and having a thickness a nickel layer (B) of 0.5 to 3 μm formed in the a copper layer (C) having a thickness of 1 to 12 μm on the nickel layer (B); and an oxide-free layer interposed between the nickel layer (B) and the copper layer (C).

Also, the present invention provides a method:

(2) A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or one side of the foil (A) and having a thickness It is a nickel layer (B) of 0.5 to 3 μm, a copper layer (C) having a thickness of 1 to 12 μm formed on the nickel layer (B), and a peel strength of 0.5 kg/cm or more.

Also, the present invention provides a method:

(3) A composite copper foil composed of copper/nickel/copper according to the above (1), comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed in the foil (A) a nickel layer (B) having a thickness of 0.5 to 3 μm on both sides or a single side, a copper layer (C) having a thickness of 1 to 12 μm formed on the nickel layer (B); and a peel strength of 0.5 kg/ More than cm.

Also, the present invention provides a method:

(4) A method for producing a composite copper foil composed of copper/nickel/copper, formed on both sides or one side of a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm by plating to a thickness of 0.5 to 3 The nickel layer (B) of μm is continuously formed into a copper layer (C) having a thickness of 1 to 12 μm by electroplating immediately after plating the nickel layer (B).

Also, the present invention provides a method:

(5) The method for producing a composite copper foil according to the above (4), wherein a rust-preventing layer having a Cr content of 10 to 50 μg/dm ² is formed on the copper layer (C).

The present invention has the following obvious effects: one can be obtained by manufacturing In the case of a composite copper foil composed of copper/nickel/copper, the bonding strength between nickel and copper can be improved, and it is suitable for a composite copper foil in which an electric circuit is formed by etching and a method for producing the same.

When manufacturing the composite copper foil composed of copper/nickel/copper of the present invention, a zigzag plating apparatus as shown in Fig. 1 can be used. As the copper foil to be used as the starting material, a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm is used. Nickel plating is performed on both sides or one side of the foil (A).

In Fig. 1, the plating layer is introduced from the left side of Fig. 1, and is moved to the right to form a nickel plating layer of a specific thickness, that is, a nickel layer (B) having a thickness of 0.5 to 3 μm. This is because, in this case, if the lower limit of the nickel layer is 0.5 μm, pinholes are likely to occur, and if the upper limit is exceeded, that is, 3 μm, the nickel layer is finally peeled off or dissolved. The burden will become larger and the production efficiency will be worse.

As shown in FIG. 1, immediately after the plating of the nickel layer (B), a copper layer (C) having a thickness of 1 to 12 μm is continuously formed by electroplating. The lower limit of the copper layer (C) is set to 1 μm. The copper layer (C) is a material for forming a circuit, and the lower limit is a thickness necessary to maintain the characteristics of the circuit. Further, the upper limit of the copper layer (C) was set to 12 μm. The reason for this is that when the layer becomes a thickness of more than 12 μm, the adjustment of the film thickness is difficult due to the limitation of the plating method (zigzag plating method), and when a film having unevenness is formed, the circuit is formed. The etchability deteriorates.

Importantly, the copper layer is continuously formed on nickel plating. Previously, there was a concern that if copper plating was continuously performed after nickel plating, the nickel plating liquid adhering to the object to be plated would be mixed with the copper plating liquid, and in the case of such a worries, avoid this. The situation is considered as common sense among the industry. However, in fact, it is known that there is not much pollution.

Further, by further adopting the above-described continuous plating method, it is understood that there is a very remarkable effect that the oxidation of the nickel layer disappears.

When the oxidation of the nickel layer is suppressed, a large effect of improving the adhesion between nickel and copper occurs. Further, the copper layer itself is a material rich in oxidation resistance, and at the stage of forming a copper plating layer, formation of an oxide film is hardly observed.

On the copper layer (C), a rust-preventing layer having a Cr content of 10 to 50 μg/dm ² can be further formed. It is often referred to as a chromium layer or a chromate layer. In Fig. 1, the step of forming the rustproof layer is also illustrated, but this step is not essential. However, it is effective in suppressing the slight oxidation of the copper plating layer or preventing the adhesion of corrosive substances.

Therefore, the rust preventing step is a preferred form. When the Cr content is less than 10 μg/dm ² , the control of the rust-preventing layer becomes difficult, and therefore it is set to the above. Further, when the Cr content exceeds 50 μg/dm ² , the effect is saturated, and the burden due to the increase in steps becomes large. Therefore, it is preferable to set the upper limit value as described above.

The copper layer (C) is formed by etching to form a copper portion of the circuit and is a thin layer, so the control of its thickness is important. Further, as described above, peeling of the copper layer (C) on the nickel layer (B) was not observed at all. It is a major feature of the invention of the present invention.

Usually, in the composite copper foil, an alkali etching liquid is used for etching. The purpose is to stop the nickel layer etching of the circuit. However, as long as it is an etching liquid which can be etched to the nickel layer, the use of other etching liquids is not inhibited even if it is not an alkali system. Replace the etchant as needed.

The etching method is not directly related to the present invention, but is understood by reference to the surrounding technology. Thereby, the copper circuit can be adjusted to have a width corresponding to the thickness of the copper layer.

The following are examples of representative and preferred plating conditions.

(copper plating: zigzag)

Copper: 10~50 g/l

Sulfuric acid: 50~100 g/l

Temperature: 40~60°C

Current density: 1~5 A/dm ²

(nickel plating)

Nickel sulfate: 250~300 g/L

Nickel chloride: 35~45 g/L

Nickel acetate: 10~20 g/L

Trisodium citrate: 15~30 g/L

Gloss agent: saccharin, butynediol, etc.

Sodium dodecyl sulfate: 30~100 ppm

pH: 4~6

Bath temperature: 50~70°C

(conditions for chromate treatment) (A) impregnated chromate treatment

K ₂ Cr ₂ O ₇ (Na ₂ Cr ₂ O ₇ or CrO ₃ ): 0.1 to 5 g / liter

Ph: 2~13

Temperature: normal temperature ~ 60 ° C

Time: 5~30 seconds

(B) Electrolytic chromate treatment

K ₂ Cr ₂ O ₇ (Na ₂ Cr ₂ O ₇ or CrO ₃ ): 2~10 g/liter

NaOH or KOH: 10~50 g/L

pH: 7~13

Bath temperature: 20~80°C

Current density D _k : 0.05~5 A/dm ²

Time: 5~30 seconds

Anode: Pt-Ti plate, lead plate, etc.

(conditions for alkali etching)

NH ₄ OH: 6 mol / liter

NH ₄ Cl: 5 mol / liter

CuCl ₂ : 2 mol / liter

Liquid temperature: 50 ° C

(Method for analyzing the adhesion amount of nickel etc.)

In order to analyze the nickel-treated surface, the sample is cut into, for example, 5 cm square, and the sample is dissolved by using a nitric acid having a concentration of 30%, and the solution in the beaker is diluted to 5000 times, and nickel is formed by atomic absorption analysis. Quantitative analysis.

(Chromium adhesion analysis method)

In order to analyze the treated surface, the reverse side was pressed with FR-4 resin and masked. The sample was boiled for 3 minutes using hydrochloric acid having a concentration of 10%, and the treated layer was dissolved, and the solution was subjected to quantitative analysis of chromium by atomic absorption analysis.

Making a copper clad laminate using the above composite copper foil, and forming the use In the circuit of the copper clad laminate, a resist pattern for circuit formation is formed on the copper layer (C), the rolled copper foil or the electrolytic copper foil (A), and an alkali etching liquid is used, and the resist pattern portion is attached. The excess portion of the rolled copper foil or the electrolytic copper foil (A) and the copper layer (C) is removed.

Next, photoresist removal is performed, and if necessary, the nickel layer (B) of the remaining portion is further removed by soft etching or the like. The method of performing the copper foil removal from the formation of the resist pattern to the unnecessary one is not necessary, and therefore will not be described.

In the case of using a copper foil, the same can be applied to the roughened surface (M surface) or the shiny surface (S surface) of the electrolytic copper foil, but the surface to be etched is usually the shiny side. In the case of using a rolled copper foil, a high-purity rolled copper foil or a rolled alloy copper foil having improved strength can also be used. The invention of the present invention encompasses all such copper foils.

Further, in carrying out the invention of the present invention, any well-known technique described above can be utilized as long as it does not contradict the invention of the present invention.

Example

Next, examples and comparative examples of the present invention will be described. Furthermore, the present embodiment is intended to facilitate understanding and is not limited to the above examples. That is, the present invention includes all aspects or modifications other than the above-described embodiments of the invention within the scope of the technical idea described in the present specification.

(Example 1)

As the base foil, a 70 μm thick electrolytic copper foil (A) was used. The electrolytic copper foil was subjected to nickel plating (B) of 0.7 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Secondly, on the nickel plating layer (B), A 10 μm plated copper layer (C) was continuously formed. Thereby, a composite copper foil composed of copper/nickel/copper was produced.

With respect to the adhesion of the composite copper foil produced in this manner, the substrate was laminated on the side of the thin copper foil at 150 ° C or higher, and the peel strength was measured. It is set to "x" when peeling is possible and peeling strength is less than 0.5 kg/cm. When it is not peeled off or the peeling strength is 0.5 kg/cm or more, it is set to "○".

In order to confirm the barrier effect of the nickel layer, a resin is applied as a copper-clad laminate on the surface of the ultra-thin copper foil, and then printed on the surface of the rolled copper foil or the electrolytic copper foil by a resist coating and exposure step. The strip circuit uses an etching solution for copper to remove excess portions of the copper foil to confirm the barrier effect.

The case where the etching to the nickel layer is stopped is set to "○", and when it is etched to the copper layer (C), it is set to "x". Further, when etching is performed until the nickel layer is stopped, the nickel layer is removed by an etching solution for nickel, thereby confirming the removability of the nickel layer. The case where the bottom can be removed is set to "○", and the case where the bottom is not removed is set to "x".

As a result of the above, the adhesion, the barrier property of the nickel layer, and the removability were good. The results are also shown in Table 1.

(Example 2)

As the base foil, a rolled copper foil (A) having a thickness of 12 μm was used. The rolled copper foil was subjected to nickel plating (B) of 0.6 μm using the plating apparatus shown in Fig. 1 and using the above plating conditions. Next, on the nickel plating layer (B), a 5 μm plated copper layer (C) was continuously formed.

Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion, the barrier property of the nickel layer, and the removability were good. The results are also shown in Table 1.

(Example 3)

As the base foil, an electrolytic copper foil (A) having a thickness of 18 μm was used. The electrolytic copper foil was subjected to nickel plating (B) of 1 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, on the nickel plating layer (B), a 10 μm plated copper layer (C) was continuously formed.

Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion, the barrier property of the nickel layer, and the removability were good. The results are also shown in Table 1.

(Example 4)

As the base foil, a rolled copper foil (A) having a thickness of 35 μm was used. The rolled copper foil was subjected to nickel plating (B) of 3 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, on the nickel plating layer (B), a 20 μm plated copper layer (C) was continuously formed. Further, chromate treatment was carried out using the above immersion conditions.

Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion, the barrier property of the nickel layer, and the removability were good. The results are also shown in Table 1.

(Example 5)

As the base foil, a rolled copper foil (A) having a thickness of 18 μm was used. The rolled copper foil was subjected to nickel plating (B) of 1 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, on the nickel plating layer (B), a 10 μm plated copper layer (C) was continuously formed. Further, chromate treatment was carried out using the above immersion conditions.

Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion, the barrier property of the nickel layer, and the removability were good. The results are also shown in Table 1.

(Comparative Example 1)

As the base foil, an electrolytic copper foil (A) having a thickness of 18 μm was used. The electrolytic copper foil was subjected to nickel plating (B) of 1 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, the plating was temporarily interrupted, and a 10 μm plated copper layer was formed on the layer (B) using a sawtooth plating apparatus as shown in FIG. Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the nickel layer was excellent in barrier properties and removability, but the strength was less than 0.5 kg/cm, and peeling occurred between the nickel layer and the thin copper foil. The results are also shown in Table 1.

When the plating is temporarily interrupted and copper plating is performed, the plating is interrupted between the nickel plating and the copper plating, and the possibility that the oxide film is formed on the nickel layer is high, and this case is considered to have an influence on the adhesion.

(Comparative Example 2)

As the base foil, a 35 μm thick electrolytic copper foil (A) was used. The electrolytic copper foil was subjected to nickel plating (B) of 10 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, a 7 μm plated copper layer was formed on the layer (B) using a sawtooth plating apparatus as shown in FIG. Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion and the barrier property of the nickel layer were good. However, since the nickel layer was thick, it was not removed in the etching of the nickel removal. The results are also shown in Table 1.

(Comparative Example 3)

As the base foil, a rolled copper foil (A) having a thickness of 70 μm was used. The rolled copper foil was subjected to nickel plating (B) of 0.3 μm using the plating apparatus shown in Fig. 1 and using the plating conditions described above. Next, a 10 μm plated copper layer was formed on the layer (B) using a sawtooth plating apparatus as shown in FIG. Thereby, a composite copper foil composed of copper/nickel/copper was produced. The other test conditions were the same as in Example 1.

As a result of the above, the adhesion was good. However, since the nickel layer was thin, nickel was removed during the removal of the copper foil, and the copper layer (C) was etched. The results are also shown in Table 1.

The present invention has the following obvious effects: one can be obtained by manufacturing In the case of a composite copper foil composed of copper/nickel/copper, the bonding strength between nickel and copper can be improved, and it is suitable for a composite copper foil in which an electric circuit is formed by etching and a method for producing the same.

Fig. 1 is a view showing an example of a meander type plating apparatus used in the production of a composite copper foil composed of copper/nickel/copper.

Claims (25)

A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or a single side of the foil (A) and having a thickness of 0.5 to 3 μm. a nickel layer (B), a copper layer (C) formed on the nickel layer (B) and having a thickness of 1 to 12 μm; and an oxide-free layer interposed between the nickel layer (B) and the copper layer (C) At least a part of the rolled copper foil or the electrolytic copper foil (A) is used as an electric circuit. A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or a single side of the foil (A) and having a thickness of 0.5 to 3 μm. a nickel layer (B), a copper layer (C) formed on the nickel layer (B) and having a thickness of 1 to 12 μm; and an oxide-free layer interposed between the nickel layer (B) and the copper layer (C) At least a part of the rolled copper foil or the electrolytic copper foil (A) and at least a part of the copper layer (C) are used as an electric circuit. A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or a single side of the foil (A) and having a thickness of 0.5 to 3 μm. a nickel layer (B), a copper layer (C) formed on the nickel layer (B) and having a thickness of 5 to 20 μm; and an oxide-free layer interposed between the nickel layer (B) and the copper layer (C) . A composite copper foil composed of copper/nickel/copper according to any one of claims 1 to 3, wherein the peel strength between the nickel layer (B) and the copper layer (C) is 0.5 kg/cm. the above. A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed in the foil (A) a nickel layer (B) having a thickness of 0.5 to 3 μm on both sides or a single side, a composite copper foil formed on the nickel layer (B) and having a copper layer (C) having a thickness of 1 to 12 μm; and the nickel layer (B) The peeling strength with the copper layer (C) is 0.5 kg/cm or more. A composite copper foil composed of copper/nickel/copper, comprising: a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm, formed on both sides or a single side of the foil (A) and having a thickness of 0.5 to 3 μm. a nickel layer (B), a composite copper foil formed on the nickel layer (B) and having a copper layer (C) having a thickness of 5 to 20 μm; and a peeling between the nickel layer (B) and the copper layer (C) The strength is 0.5 kg/cm or more. A composite copper foil comprising copper/nickel/copper according to the fifth or sixth aspect of the patent application, wherein at least a part of the rolled copper foil or the electrolytic copper foil (A) is used as an electric circuit. A composite copper foil comprising copper/nickel/copper according to claim 5 or 6, wherein at least a portion of the rolled copper foil or the electrolytic copper foil (A) and at least a portion of the copper layer (C) are used as Circuit. A copper-clad laminate produced by using the composite copper foil of any one of claims 1 to 8. A printed wiring board produced by using the composite copper foil of any one of claims 1 to 8. An electronic ‧ electrical device using a printed wiring board of claim 10 A method for manufacturing a composite copper foil composed of copper/nickel/copper, on both sides or single sheets of rolled copper foil or electrolytic copper foil (A) having a thickness of 10 to 150 μm a nickel layer (B) having a thickness of 0.5 to 3 μm is formed by electroplating, and immediately after plating the nickel layer (B), a copper layer (C) having a thickness of 1 to 12 μm is continuously formed by electroplating; the composite copper The foil is used for the purpose of using at least a part of the rolled copper foil or the electrolytic copper foil (A) as a circuit. A method for manufacturing a composite copper foil composed of copper/nickel/copper, forming a nickel layer having a thickness of 0.5 to 3 μm by electroplating on both sides or one side of a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm. (B), immediately after plating the nickel layer (B), a copper layer (C) having a thickness of 1 to 12 μm is continuously formed by electroplating; the composite copper foil is used for the rolled copper foil or the electrolytic copper foil At least a portion of (A) and at least a portion of the copper layer (C) are used for circuit purposes. A method for manufacturing a composite copper foil composed of copper/nickel/copper, forming a nickel layer having a thickness of 0.5 to 3 μm by electroplating on both sides or one side of a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm. (B) Immediately after plating the nickel layer (B), a copper layer (C) having a thickness of 5 to 20 μm is continuously formed by electroplating. A method for manufacturing a composite copper foil composed of copper/nickel/copper, forming a nickel layer having a thickness of 0.5 to 3 μm by electroplating on both sides or one side of a rolled copper foil or an electrolytic copper foil (A) having a thickness of 10 to 150 μm. (B), immediately after plating the nickel layer (B), a copper layer (C) having a thickness of 1 to 12 μm is continuously formed by electroplating, and between the nickel layer (B) and the copper layer (C) The peel strength is 0.5 kg/cm or more. A method for manufacturing a composite copper foil composed of copper/nickel/copper, on both sides or single sheets of rolled copper foil or electrolytic copper foil (A) having a thickness of 10 to 150 μm a nickel layer (B) having a thickness of 0.5 to 3 μm is formed by electroplating, and immediately after plating the nickel layer (B), a copper layer (C) having a thickness of 5 to 20 μm is continuously formed by electroplating, the nickel layer The peel strength between (B) and the copper layer (C) is 0.5 kg/cm or more. The method for producing a composite copper foil according to any one of claims 14 to 16, wherein the composite copper foil is used for the use of at least a part of the rolled copper foil or the electrolytic copper foil (A) as a circuit. . The method for producing a composite copper foil according to any one of claims 14 to 16, wherein the composite copper foil is used for at least a part of the rolled copper foil or the electrolytic copper foil (A) and the copper layer ( At least a portion of C) is used for the purpose of the circuit. The method for producing a composite copper foil according to any one of claims 12 to 16, wherein a rust-preventing layer having a Cr content of 10 to 50 μg/dm ² is formed on the copper layer (C). The method for producing a composite copper foil according to claim 17, wherein a rust-preventing layer having a Cr content of 10 to 50 μg/dm ² is formed on the copper layer (C). The method for producing a composite copper foil according to claim 18, wherein a rust-preventing layer having a Cr content of 10 to 50 μg/dm ² is formed on the copper layer (C). A manufacturing method of a printed wiring board, comprising the steps of: preparing a composite copper foil according to any one of claims 1 to 8, and the copper layer (C) and the rolled copper of the composite copper foil Foil or electrolytic copper foil (A) The step of forming a circuit. A method of producing a printed wiring board according to claim 22, comprising the step of producing a copper clad laminate using the prepared composite copper foil. A method for manufacturing a printed wiring board, comprising the steps of: preparing a composite copper foil composed of copper/nickel/copper, the composite copper foil composed of copper/nickel/copper having a rolled copper foil or electrolysis having a thickness of 10 to 150 μm a copper foil (A), a nickel layer (B) formed on both sides or a single side of the foil (A) and having a thickness of 0.5 to 3 μm, and a copper layer formed on the nickel layer (B) and having a thickness of 1 to 20 μm ( C), and the oxide-free layer is between the nickel layer (B) and the copper layer (C), or the peel strength between the nickel layer (B) and the copper layer (C) is 0.5 kg/cm And the step of forming a circuit on the copper layer (C) of the composite copper foil and the rolled copper foil or the electrolytic copper foil (A). A method of producing a printed wiring board according to claim 24, comprising the step of producing a copper clad laminate using the composite copper foil made of the copper/nickel/copper.