JP3392066B2 - Composite copper foil, method for producing the same, copper-clad laminate and printed wiring board using the composite copper foil - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite copper foil for providing an ultrathin copper foil for forming a printed wiring (circuit) substrate and a method for producing the same, more specifically, between a support metal layer and an ultrathin copper foil. TECHNICAL FIELD The present invention relates to a composite copper foil having an organic release layer capable of imparting uniform peel strength to a copper foil and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high density of electronic equipment, the circuit width and circuit spacing of printed wiring boards used have become finer year by year, and the copper used accordingly. Foil thickness is 35 micron, 18 micron to 1
It tends to be thinned to 2 microns. Recently, the demand has become stronger, and trial production of ultra-thin copper foil satisfying such demand has been made. However, thin copper foil with a thickness of 12 microns or less easily causes wrinkles and breaks. Extremely difficult to manufacture and handle. Further, when the ultra-thin copper foil is used for the outer layer of the multilayer printed wiring board, there is a problem that the copper foil is deformed due to the unevenness of the inner layer circuit at the time of stacking, which causes damage or wrinkles. It is strongly desired to develop a method for solving these problems associated with the handling of foil.

In order to meet such a demand, a composite copper foil in which an ultrathin copper foil is detachably supported on a support metal layer has been proposed, and some support metal materials and release layer materials have been proposed. Is illustrated. Further, in the method for manufacturing a printed wiring board using such a composite copper foil,
A 70 μm metal support is electrodeposited with copper of about 1 to 12 μm to produce a composite copper foil, and a prepreg such as glass fiber impregnated epoxy resin is brought into contact with the copper foil surface of the composite copper foil, and then heated. After being pressure-bonded and brought into close contact, the support is peeled off to manufacture a printed wiring board.

By the way, conventionally, when a copper support is used for electrodepositing copper, it has been proposed to use chromium as a release layer (for example, Japanese Patent Publication No. 53-1).
8329).

Also, when an aluminum support is used, a release layer formed from, for example: sulfides or oxides of Cr, Pb, Ni, Ag (eg US Pat. No. 3,998,60).
No. 1); a release layer formed by plating with Ni or Ni alloy after substitution with zinc (for example, US Pat. No. 3,936,54).
No. 8); a release layer having an aluminum oxide film formed again after removing the oxide on the surface (for example, Japanese Patent Publication No. Sho 60-31915 and British Patent No. 1,458, 260); and formed from silicon. Release layers (eg, US Pat. No. 4,
No. 357,395) and the like have been proposed.

However, these conventionally proposed copper foils with a support (composite copper foils) have the following problems.

1) Since the peeling layer cannot be formed uniformly on the entire surface of the support, the peel strength between the support and the ultrathin copper foil is not uniform. Therefore, when the support is peeled off after the obtained composite copper foil is laminated on the substrate, the ultrathin copper foil remains on the support, or the support remains on the ultrathin copper foil to obtain a desired conductor circuit. I can't. If the peel strength is weak, the ultra-thin copper foil partially or entirely floats from the support during manufacturing and use.

2) When an inorganic material such as oxide, sulfide or chromium is used for the peeling layer, the inorganic material remains on the surface of the ultrathin copper foil after peeling the support. Therefore, when it is used for forming a circuit or the like, it is necessary to remove the remaining inorganic substances, and an additional step such as soft etching is required, which is troublesome.

3) When a harmful substance such as chromium is used as the peeling layer, the chromium cannot be reused because the chromium adheres to the surface after peeling the support, and there is a problem in scrap disposal. Further, there is a problem in waste liquid treatment, and there is a problem in manufacturing and environment.

4) When a composite copper foil having the above metal or metal oxide layer as a release layer is laminated on a base material such as an epoxy prepreg at high temperature, the metal of the release layer diffuses into both the support and the ultrathin copper foil. Therefore, it is difficult to peel the support from the base material.

As described above, the conventional composite copper foil is
It has many problems to be solved and is not generalized industrially.

The present invention is a process of examining various problems in the conventional composite copper foil using such a metal and / or a metal compound as a release layer, and is a completely new organic compound for the release layer of the composite copper foil. It was completed by examining.

That is, the present inventors have examined conventional composite copper foils in which a metal and / or a metal compound is used as a peeling layer, and as a result, as described above, the peeling layer is non-uniform, so that If the peel strength becomes non-uniform, or if the peeling layer is heated during lamination, the peeling layer metal is diffused into both the support and the ultra-thin copper foil, so the peel strength of the support from the ultra-thin copper foil is too strong However, I discovered that there are practical problems.

Therefore, the present inventors have studied various organic compounds suitable for the release layer of the composite copper foil used for manufacturing a printed wiring board, and solved the above-mentioned problems by interposing a specific organic compound. The inventors have found that they can do so and have completed the present invention.

By the way, US Pat. No. 3,281,339
No. benzotriazole (BT) as a stripping agent for producing a copper foil or a copper sheet by electrodeposition.
A) is disclosed. In this document, BTA is primarily used to enable continuous production of copper sheets using a rotating drum cathode by continuously separating the copper sheet electrodeposited on the BTA coated surface of the rotating drum cathode. ing. However, this document does not disclose anything about a composite copper foil for producing a printed wiring board and properties and materials suitable for the release layer.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite copper foil and a method for producing the same in which the problems of the prior art described above are solved. Another object of the present invention is to provide a copper clad laminate and a printed wiring board using such a composite copper foil.

[0017]

SUMMARY OF THE INVENTION As described above, the present invention maintains the above properties suitable as a release layer for a composite copper foil even when a certain organic compound is exposed to high temperatures during the production of a printed wiring board. It was made based on the discovery of the inventors of the present invention.

In the present specification, "peel strength (A)"
Represents the force required to peel the support metal layer from the ultrathin copper foil laminated on the substrate. Also, peel strength (B) "
Represents the force required to peel the ultrathin copper foil laminated on the base material from the base material.

The composite copper foil according to the present invention is characterized by having an organic release layer between the support metal layer and the ultrathin copper foil.

In the composite copper foil according to the present invention, the organic release layer generally has the following characteristics. 1. It is easy to form the release layer. 2. The peel strength (A) between the ultrathin copper foil and the support metal layer is uniform, and shows a low value as compared with the peel strength (B) of the ultrathin copper foil after being laminated on the substrate. 3. Since no inorganic material is used, a mechanical polishing step and an acid washing step for removing the inorganic material remaining on the surface of the ultrathin copper foil are not required. Therefore, the formation of the wiring pattern is simplified by reducing the number of processing steps. 4. Although the peel strength (A) is small, it is sufficient to prevent the ultrathin copper foil from separating from the support metal layer during handling of the composite copper foil. 5. The composite copper foil has sufficient peel strength (B) after being laminated on the base material, and the ultra-thin copper foil does not peel off from the base material during processing into a printed wiring board. 6. The support metal layer can be separated from the ultrathin copper foil even after lamination at high temperature. 7. Since it is easy to remove the release layer remaining on the support metal layer, it is easy to reuse the support metal layer.

In the present invention, the organic compound useful for producing the composite copper foil preferably has the following characteristics. 1. These organic compounds can form a chemical bond with copper. 2. Maintaining the ability to separate the support metal layer from the ultra-thin copper foil even when exposed to the temperature used when laminating the copper foil on the insulating substrate, preferably 150 ° C. or higher, particularly 175 to 200 ° C. There is. 3. Form chemical bonds with ultra-thin copper foil and support metal layer,
Moreover, the peel strength (A) of the support copper foil from the ultra-thin copper foil is lower than the peel strength (B) of the ultra-thin copper foil from the insulating base material. By such peel strength (A), it is possible to prevent the ultra-thin copper foil from separating from the support during handling and lamination of the composite copper foil, and to remove the support metal layer after the composite copper foil is laminated. Is possible. 4. The copper foil can be electrodeposited uniformly on the support metal layer.

Examples of preferred organic compounds include nitrogen-containing compounds, sulfur-containing compounds and carboxylic acids. Preferably, the nitrogen-containing compound is a nitrogen-containing compound having a substituent (functional group), for example, a triazole compound having a substituent. Examples of the triazole compound having a substituent include carboxybenzotriazole (CBTA), N ′, N′-bis (benzotriazolylmethyl) urea (BTD-U) and 3-amino-1H-1,2,4. -
Triazole (ATA) may be mentioned. As the sulfur-containing compound, mercaptobenzothiazole (M
Examples thereof include BT), thiocyanuric acid (TCA) and 2-benzimidazole thiol (BIT). The carboxylic acid is preferably a monocarboxylic acid. Examples of monocarboxylic acids include oleic acid, linoleic acid and linoleic acid.

The present invention provides a composite copper foil provided with an organic release layer having the above-mentioned characteristics between a support metal layer and an ultrathin copper foil. In the present invention, the support metal layer may be a foil.

The present invention also provides a composite copper foil comprising a step of forming an organic release layer on a support metal layer, and a step of forming an ultrathin copper foil layer on the organic release layer by electrodeposition. A manufacturing method is provided.

The copper-clad laminate of the present invention is formed of the composite copper foil of the present invention and an insulating base material on which the composite copper foil is laminated. In the copper-clad laminate of the present invention, the support metal layer may be peeled off from the composite copper foil on the base material.

In the printed wiring board according to the present invention, the support metal layer is peeled off from the composite copper foil of the copper-clad laminate to expose the ultrathin copper foil, and a wiring pattern is formed on the exposed ultrathin copper foil. It is characterized by being formed.

The present invention also provides a multilayer printed wiring board using the above-mentioned printed wiring board.

That is, in the multilayer printed wiring board according to the present invention, the above-mentioned composite copper foil is laminated on at least one surface of the inner layer board on which a wiring pattern is formed in advance to form a copper-clad laminate, and the copper-clad laminate is formed. The support metal layer can be peeled off from the plate to expose the ultrathin copper foil, and a wiring pattern can be formed on the ultrathin copper foil to form a multilayer structure. A plurality of such multilayer printed wiring boards may be laminated.

The multilayer printed wiring board according to the present invention can be manufactured by laminating a plurality of printed wiring boards according to the present invention.

[0030]

DETAILED DESCRIPTION OF THE INVENTION The composite copper foil of the present invention will be described in more detail below.

The composite copper foil of the present invention is characterized by having an organic release layer between the support metal layer and the ultrathin copper foil.

FIG. 1 is a schematic sectional view showing an embodiment of the composite copper foil according to the present invention. As shown in the figure, the composite copper foil 1 of this embodiment is obtained by forming the organic release layer 3 and the ultrathin copper foil 4 in this order on the support metal layer 2.

In the present invention, the organic release layer preferably has the above-mentioned characteristics. Such release layers are formed from organic compounds, especially nitrogen-containing compounds, sulfur-containing compounds and carboxylic acids.

As the support metal layer, copper or a copper alloy is preferably used because the organic release layer forms a chemical bond with copper. The organic compound used in the present invention may be applied to a support material other than copper and a copper alloy, for example, copper-plated aluminum. Also,
As the support, other materials can be used as long as the release layer forms a uniform chemical bond as in the case of the ultrathin copper foil. The thickness of the support metal layer is not limited and may be a foil having a thickness of 10 to 18 μm. Since a typical support metal layer is relatively thin, this is sometimes referred to as a foil,
The support metal layer may be thicker than normal foil, for example about 5
Thicker support sheets of mm or less can also be used.

The support metal layer may be an electrodeposited copper foil,
Such an electrodeposited copper foil typically has a rough surface (or matte surface) and a smooth surface (or shiny surface).
The release layer on which the ultrathin copper foil is electrodeposited may be formed on either the matte surface or the glossy surface. An ultrathin copper foil formed by forming a release layer on a glossy surface and electrodepositing copper on it has a small surface roughness and is suitable for forming a fine pitch wiring pattern. On the other hand, when the release layer is formed on the matte surface and electrodeposition is performed, the surface roughness of the ultrathin copper foil formed is increased, and the bonding strength (B) from the insulating base material can be improved.

The thickness of the ultrathin copper foil layer formed on such an organic release layer is usually 12 μm or less, but may be thinner, for example, 5 to 7 μm or less. Good. Copper foils having a thickness greater than 12 microns can also be manufactured by conventional manufacturing methods and can be handled without a support metal layer. The ultra-thin copper foil is formed on the support metal layer by electrodeposition, is suitable for forming a circuit pattern, and is a composite copper foil having a support metal layer, an organic release layer, and an ultra-thin copper foil. Then, the appropriate peel strengths (A) and (B) as described above can be obtained.

We have found that certain nitrogen-containing compounds and sulfur-containing compounds, especially heterocyclic compounds,
It has been found to be useful as an organic release layer. As this type of nitrogen-containing compound, a nitrogen-containing compound having a substituent (functional group) is preferable. Among these, triazole compounds having a substituent (functional group), for example, carboxybenzotriazole (CBTA), N ', N'-bis (benzotriazolylmethyl) urea (BTD-U) and 3-
Amino-1H-1,2,4-triazole (ATA) and the like are particularly preferable. Further, as this type of sulfur-containing compound,
Mercaptobenzothiazole (MBT), thiocyanuric acid (TCA) and 2-benzimidazole thiol (B
IT) and the like, of which MBT and TCA are particularly
Is desirable. It has been discovered that with some similar compounds it is not possible to separate the ultra-thin copper foil from the support copper after heating, as shown in the examples below.

Another class of compounds that have been found to be useful as organic release layers are carboxylic acids, such as high molecular weight carboxylic acids. Of such carboxylic acids, monocarboxylic acids, such as fatty acids derived from animal or vegetable fats or oils, are preferred. These may be saturated or unsaturated. However, as shown in the examples below, not all carboxylic acids are useful.

Carboxylic acids which have been found to be useful are fatty acids (high molecular weight monocarboxylic acids), especially unsaturated fatty acids such as oleic acid, linoleic acid and linoleic acid. Other acids lacking the ability to separate the ultra-thin copper foil from the support copper foil are shown in the examples below.

In the composite copper foil of the present invention, the support metal layer can be peeled off from the ultrathin copper foil after being laminated on the insulating base material,
The peel strength (A) of the support metal layer from the ultra-thin copper foil is JI
When measured according to S-C-6482, 0.005
˜0.3 kgf / cm is desirable, and practically 0.005 to 0.1 kgf / cm is particularly desirable.
If it is less than 0.005 kgf / cm, the peeling strength is too weak, and swelling or lifting of the ultra-thin copper foil occurs during manufacturing, lamination, or punching, which is not preferable. Further, if it exceeds 0.3 kgf / cm, when the support is peeled off, US Pat.
Special processing as described in Japanese Patent Publication No. 2 is required.

In the composite copper foil of the present invention, the peel strength (A) of the support metal layer from the ultrathin copper foil has little or no variation. Therefore, the peel strength (A) is uniform over the entire surface of the composite copper foil of each example, and throughout the composite copper foil of all the examples.

Further, after the support metal layer is peeled off, only a thin organic coating is attached to the surface of the ultrathin copper foil, and this organic coating is pickled with a dilute acid solution. It can be easily removed by just Therefore, no harsh pickling or soft etching steps are required.
In addition, the organic coating adhered on the ultrathin copper foil also has a rust preventive effect. Furthermore, the support metal layer can be easily reused after peeling, so that there are no manufacturing or environmental problems.

In the method for producing the composite copper foil of the present invention, the organic release layer is formed on the support metal layer, and the ultrathin copper foil layer is formed on the organic release layer. At this time, prior to the formation of the organic release layer, it is preferable to remove the oxide film on the surface of the support metal layer so that a uniform release strength (A) can be obtained. The oxide film can be removed, for example, by washing the support in a dilute acid solution, for example, dilute sulfuric acid. The organic release layer may be formed by a dipping method or a coating method, or any method that forms a uniform layer on the support.
For example, in the immersion method, the support metal layer is immersed in an aqueous solution of an organic compound such as triazole to form an organic release layer. The concentration of the aqueous solution is preferably 0.01 to 10 g / L, particularly preferably 0.1 to 10 g / L, and the immersion time is 5 to 60.
Seconds are preferred. The effect of the release layer formed by the high concentration and the long immersion time does not diminish, but it is not preferable from the viewpoint of economical efficiency and productivity. After removing the support from the solution, excess deposits are preferably washed with water so that only a very thin organic release layer remains on the support surface. The thickness of the peeling layer after washing is usually 30 to 1
It is considered to be 00Å, particularly preferably 30 to 60Å. The thickness of the organic release layer can be measured by, for example, SIM (scanning ion microscope) or TEM (transmission electron microscope). In the present invention, the thickness of the release layer is not limited to such a value, but if it is too thin, the ultrathin copper foil will be bonded to the support, and if it is too thick, the copper is evenly distributed. It becomes impossible to electrodeposit.

The ultrathin copper foil is electrodeposited on the organic release layer provided on the support metal. Examples of the method for electrodepositing copper include a method using a copper pyrophosphate electrodeposition bath, an acidic copper sulfate electrodeposition bath, and the like. The method using any type of electrodeposition bath can be applied, but a preferable type of electrodeposition bath can be selected according to the purpose.

For example, in order to avoid unwanted pinholes and / or porosity, and for more uniform electrodeposition of copper, a substantially acid-free electrolyte bath, such as a copper cyanide bath or a copper pyrophosphate bath. Is preferably used for the first electrodeposition. Electrodeposition of copper pyrophosphate is recommended in terms of environment and safety. When a two-step copper electrodeposition process is used, primary copper electrodeposition is performed in a copper pyrophosphate bath to 0.5 to 1.0 μm, and then a secondary copper electrodeposition is performed in a copper sulfate electrodeposition bath. It is preferable to electrodeposit up to the ultrathin copper foil thickness of, for example, 12 μm.

Conditions for electrodeposition of copper pyrophosphate are not particularly limited. However, the concentration range of copper in the copper pyrophosphate electrodeposition bath is preferably 10 to 50 g / L, and the concentration range of potassium pyrophosphate is preferably 100 to 700 g / L. The pH of the electrolytic solution is preferably 8 to 12, the bath temperature is preferably 30 to 60 ° C., and the current density is preferably 1 to 10 A / dm ² .

On the other hand, from the viewpoint of productivity and economy, electrodeposition using a copper sulfate bath is preferable, and the sulfuric acid barrel bath is effective even if the copper foil layer is not electrodeposited first from the copper pyrophosphate bath. Can be used. The conditions for the acidic copper sulfate plating are not particularly limited. However, the concentration range of copper in the copper sulfate plating bath is preferably 30 to 100 g / L, and the concentration range of sulfuric acid is 50.
~ 200 g / L is preferred. The bath temperature of the electrolyte is 30
-80 degreeC is preferable, and current density is 10-100A / dm.
² is preferred.

In order to improve the adhesion between the ultra-thin copper foil of the composite copper foil and the insulating base material on which the composite copper foil is laminated, a bonding accelerating treatment such as electrodeposition is performed on the surface of the ultra-thin copper foil by a conventionally known method. A roughening treatment (cobbing treatment) for electrodepositing the conductive fine particles on the surface of the foil by adjusting the conditions may be performed. An example of roughening treatment is
For example, it is disclosed in US Pat. No. 3,674,656. In addition, the surface of the ultrathin copper foil may be subjected to a rust preventive treatment in order to prevent the ultrathin copper foil from being oxidized. The anticorrosion treatment may be carried out alone or after the roughening treatment. The anticorrosion treatment is generally performed by electrodeposition of a kind selected from zinc, zinc chromate, nickel, tin, cobalt and chromium on the surface of an ultrathin copper foil. An example of such a method is disclosed in US Pat. No. 3,625,844.

The ultrathin copper foil produced in this manner, that is, the ultrathin copper foil supported on the support metal through the organic release layer, is laminated on the insulating base material under heating and pressure,
A copper-clad laminate formed of the composite copper foil and the insulating base material is obtained.

FIG. 2 is a schematic sectional view showing an embodiment of the copper-clad laminate according to the present invention. As shown in the figure, the copper-clad laminate 5 is prepared by using the composite copper foil 1 as shown in FIG.
It is manufactured by stacking on the substrate 6.

The lamination temperature is typically 150 ° C. or higher, preferably 175 to 200 ° C. As the insulating base material,
Any resin base material generally used for electronic devices can be used without particular limitation. For example, FR-
4 base materials (glass fiber reinforced epoxy), paper-phenol base material, paper-epoxy base material and the like. When the support metal layer is peeled off from this copper-clad laminate, a copper-clad laminate formed of an ultrathin copper foil and an insulating base material is obtained.

Now, referring to FIG. 2, from the ultra-thin copper foil 4 so that the support metal layer 2 can be separated from the ultra-thin copper foil 4 after the composite copper foil 1 is laminated on the insulating substrate 6. The peel strength (A) (indicated by A in FIG. 2) of the support metal 2 is J
When measured according to IS-C-6481, it is smaller than the peel strength (B) (indicated by B in FIG. 2) of the ultrathin copper foil 4 from the base material 6.

At this time, the ultra-thin copper foil has a peel strength (B) of JI
Since it is thin and too weak for direct measurement according to S-C6481, copper is electrodeposited on an ultrathin copper foil to a total thickness of 18 μm, and the peel strength (B) is measured.

Such a copper-clad laminate can be preferably used for manufacturing a printed wiring board.

For example, the printed wiring board according to the present invention is manufactured by peeling the support metal layer from the copper-clad laminate to expose the ultrathin copper foil, and then forming a wiring pattern on the ultrathin copper foil. can do.

FIG. 3 shows a preferred embodiment of the printed wiring board according to the present invention. As shown in the figure, the printed wiring board 7 of this embodiment includes a substrate 6 and a printed wiring pattern 8 formed on the substrate 6.

In the printed wiring board 7 of this embodiment, the ultra-thin copper foil 4 of the copper-clad laminate 7 shown in FIG. 2 is exposed by peeling the support metal 2, and the remaining peeling layer 3 is left as necessary. Then, the wiring pattern 8 is formed on the exposed ultra-thin copper foil 4.
Is manufactured. Further, a multilayer printed wiring board can be easily manufactured by using such a printed wiring board.

For example, in a multilayer printed wiring board according to the present invention, the above-mentioned composite copper foil is laminated on at least one surface of an inner layer board on which a wiring pattern is formed in advance to form a copper clad laminate, and the copper clad laminate is formed. From the above, the ultra-thin copper foil can be exposed by peeling the support metal layer, and a wiring pattern can be formed on the ultra-thin copper foil to form a multilayer structure.

The multilayer printed wiring board can also be manufactured by laminating a plurality of printed wiring boards according to the present invention.

That is, the multilayer printed wiring board is formed by laminating the above-mentioned composite copper foil on at least one surface of the printed wiring board according to the present invention to form a copper-clad laminate, and forming the copper-clad laminate from the support metal. Exposing the ultra-thin copper foil by peeling the layer, and forming a wiring pattern on the ultra-thin copper foil,
It can be manufactured in multiple layers.

FIG. 4 is a schematic cross-sectional view showing one mode of a copper-clad laminate used for manufacturing the multilayer printed wiring board shown in FIG. As shown in FIG. 4, the copper clad laminate 11 of this embodiment is manufactured by laminating the composite copper foil 1 on at least one surface of the inner layer plate 12 on which a wiring pattern is formed in advance.

The composite copper foil 1 has a support metal 2, a release layer 3 and an ultrathin copper foil 4 formed on the support metal 2. The inner layer plate 12 includes a substrate 6'and a wiring pattern 8'formed on the substrate 6 '. In this copper-clad laminate 11, the ultra-thin copper foil 4 of the composite copper foil 1 is the substrate 6
It faces the wiring pattern 8 ′ of the inner layer board 11 via.

FIG. 5 is a schematic sectional view showing an embodiment of the multilayer printed wiring board according to the present invention. This printed wiring board can be manufactured from the copper-clad laminate 11 shown in FIG.
Explaining with reference to FIG. 4 and FIG. 5, the multilayer printed wiring board 13 peels off the support metal 1 of the copper-clad laminate 11, removes the remaining peeling layer 3 if necessary, and is then exposed. The wiring pattern 8 can be formed on the ultra-thin copper foil 4 to be manufactured.

In the copper-clad laminate 11 shown in FIG. 4, the inner layer plate 12 may be the printed wiring board 7 as shown in FIG. In such a case, the multilayer laminate 13 shown in FIG. 5 is formed by laminating two printed wiring boards according to the present invention.

[0065]

According to the composite copper foil of the present invention, the peel strength (A) of the support is provided by providing the organic release layer made of a specific organic compound between the support metal layer and the ultrathin copper foil. ) Is uniform and moderate, and an ultrathin copper foil with good handleability and peelability is obtained.

According to the composite copper foil of the present invention, since no metal is used for the release layer, only a thin organic film is attached to the surface of the ultrathin copper foil after the support is peeled off. Prior to manufacturing the substrate, it is only necessary to simply pickle the ultra-thin copper foil, and there is no need for a step such as a soft etching step when metal or metal oxide is used for the release layer. The system coating also has a rust preventive effect. Further, in the composite copper foil according to the present invention, since no metal is used in the release layer, it is possible to reuse the support after peeling,
Waste liquid treatment is easy and no environmental problems occur.

According to the method for producing a composite copper foil of the present invention, a uniform organic release layer can be very easily prepared by immersing in a solution containing a specific organic compound or applying a solution containing a specific organic compound. Can be formed.

[0068]

The present invention will be described in more detail based on the following examples.

[0069]

Example 1 An electrolytic copper foil having a thickness of 35 μm was prepared as a support metal layer. Such an electrolytic copper foil has a rough surface (matte surface) and a smooth (glossy) surface. An organic release layer was formed on the glossy surface side as follows, and then primary copper electrodeposition, secondary copper electrodeposition, roughening treatment and rust prevention treatment were performed. (A) Release Layer Formation A copper foil having a thickness of 35 μm was immersed in a 2 g / L solution of carboxybenzotriazole (CBTA) at 30 ° C. for 30 seconds and then taken out and washed with deionized water to form an organic release layer of CBTA.

The thickness of the obtained organic release layer was measured from an image obtained by SIM (scanning ion microscope).
It was 0Å. (B) Primary Copper Electrodeposition On the surface of the organic release layer formed, a copper pyrophosphate copper electrodeposition bath having a pH of 8.5 containing 17 g / L of copper and 500 g / L of potassium pyrophosphate was used, and the bath temperature was 50. ℃, current density 3A /
Cathodic electrolysis was performed at dm ² to deposit copper having a thickness of 1 μm. (C) The surface of the ultra-thin copper foil formed by secondary copper electrodeposition was washed with water, and a copper sulfate electrodeposition bath containing 80 g / L of copper and 150 g / L of sulfuric acid was used to obtain a bath temperature of 50 ° C. and a current density of 60 A / Cathodic electrolysis at dm ² and 5 μm
Copper was deposited to form an ultrathin copper foil layer having a total thickness of 6 μm. (D) Roughening treatment The surface of the ultrathin copper foil layer thus formed was subjected to a roughening treatment by a conventionally known method. The current density was increased to form conductive copper fine particles on the surface of the ultrathin copper foil. (E) Anticorrosion treatment The surface of the ultrathin copper foil layer that had been roughened was subjected to anticorrosion treatment of zinc chromate by a conventionally known electrodeposition method to obtain a composite copper foil.

The composite copper foil thus obtained was laminated on four commercially available 0.1 mm FR-4 prepregs, and 175
° C., to obtain a molded to the copper-clad laminate by 60 minutes heating and pressing under the conditions of 25 kg / cm ^2. Using this copper-clad laminate, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultra-thin copper foil was measured according to JIS-C-6481, and was 0.015 kgf. It was / cm. Further, the peel strength (A) was moderate and uniform over the entire surface of the sample, so that the support copper foil could be easily peeled from the copper-clad laminate.

[0072]

Example 2 In the release layer formation in the step (A) of Example 1, N, N ′ bis (benzotriazolylmethyl) urea (B) was used instead of carboxybenzotriazole (CBTA).
TD-U) 2 g / L solution was used, and the organic release layer was formed by the same procedure as in Example 1.
A composite copper foil was obtained.

The composite copper foil thus obtained was laminated on four commercially available 0.1 mm FR-4 prepregs, and 140
A copper clad laminate was obtained by molding by heating and pressurizing for 60 minutes under the condition of ° C and 25 kg / cm ² . Using this copper-clad laminate, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultrathin copper foil was measured in accordance with JIS-C-6481, and was found to be 0.025 kgf. It was / cm.
Further, the peel strength (A) was moderate and uniform over the entire surface of the sample, so that the support copper foil could be easily peeled from the copper-clad laminate.

[0074]

Example 3 Except that the organic coating film peeling layer was formed by using 2 g / L solution of benzotriazole (BTA) instead of carboxybenzotriazole (CBTA) in the peeling layer formation in the step (A) of Example 1. A composite copper foil was obtained by the same procedure as in Example 1.

The composite copper foil thus obtained was laminated on four commercially available 0.1 mm FR-4 prepregs, and 140
A copper-clad laminate was obtained by heating and pressurizing for 60 minutes under the conditions of ° C and 25 kg / cm ² . Using this copper-clad laminate, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultrathin copper foil was measured according to JIS-C-6481 and found to be 0.043 kgf. It was / cm. Further, the peel strength (A) was moderate and uniform over the entire surface of the sample, so that the support copper foil could be easily peeled from the copper-clad laminate. Furthermore, this copper-clad laminate is used for 17
After heating at 5 ° C. for 60 minutes, it was cured.

[0076]

Example 4 In the peeling layer formation in the step (A) of Example 1, a mixed solution of 2 g / L of carboxybenzotriazole and 0.5 g / L of benzotriazole (BTA) was used instead of carboxybenzotriazole (CBTA). A composite copper foil was obtained by the same procedure as in Example 1 except that the organic release layer was formed by using the same procedure.

The composite copper foil thus obtained was placed on two commercially available 0.1 mm polyimide prepregs at 216 ° C. and 25 ° C.
A copper-clad laminate was obtained by molding by heating and pressurizing for 270 minutes under the condition of kg / cm ² . Using this copper-clad laminate, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultra-thin copper foil was measured according to JIS-C-6481, and was found to be 0.009 kgf. It was / cm. Also,
The peel strength (A) was moderate and uniform over the entire surface of the sample, and therefore the support copper foil could be easily peeled from the copper-clad laminate.

[0078]

[Embodiment 5] Inner layer material (copper foil thickness 3
The composite copper foil prepared in Example 1 was laminated on both sides of the (5 micron) via a commercial 0.18 mm FR-4 prepreg by pressing. The press conditions at this time are 175 ° C. and 25
It was kg / cm ² and 60 minutes. After cooling, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultra-thin copper foil was measured according to JIS-C6481 and was 0.015 kgf / cm. The support copper foil could be easily peeled off from the copper-clad laminate, and the adhesive strength was appropriate.

[0079]

Example 6 After using the copper clad laminate prepared in Example 1 to perform a drilling process with a diameter of 0.3 mm, a conventionally known desmear treatment using a potassium permanganate solution was performed to remove the epoxy. , Then panel plating (plating thickness 15μ
m) was performed. Furthermore, line width / line spacing = 50 microns / 5
A circuit of 0 micron was formed to obtain a printed wiring board.
At this time, the circuit formability was good. When two printed wiring boards were laminated by heating and compressing them through a FR-4 prepreg of 0.18 mm to obtain a multilayer printed wiring board having four conductor layers, there was no problem. The ultra-thin copper foil did not break or wrinkle. Therefore, in each of Examples 5 and 6, a good multilayer printed wiring board having minute 50 μm circuit wiring and spacing was obtained.

[0080]

Example 7 The ultrathin copper foil of the copper-clad laminates obtained in Examples 1-5 was plated with copper to a thickness of 18 μm. The peel strength (B) when peeling this from the substrate is JIS-
It was measured according to C-6481.

The peel strength (B) of the ultra-thin copper foil is JIS-C.
Since it is too thin for direct measurement according to −6481, additional electrodeposition was applied to the ultrathin copper foil to a thickness of 18 μm in this way.

A circuit was formed by the etching method using the copper-clad laminate. Line width / line spacing = 50 microns / 50 microns. The results obtained are shown in Table 1.
Shown in.

[0083]

[Table 1]

The above results fully satisfy the performance as a copper-clad laminate for electronic equipment. Moreover, it was very excellent in forming fine circuits. It can be concluded that the peel strength (B) of the ultra-thin copper foil is comparable to conventional thickness copper foil and is greater than the peel strength (A) measured between the ultra-thin copper foil and the support metal layer. . Further, these laminated bodies can provide a very excellent wiring pattern free from breakage and short circuit in the wiring width and spacing of 50 μm.

[0085]

Example 8 An electrolytic copper foil having a thickness of 35 μm was prepared as a support metal layer. On the glossy side, do the following:
An organic release layer was formed, and then copper electrodeposition was performed. The copper foil of (A) a release layer formed 35 [mu] m, and washed <br/> purification in aqueous solution of sulfuric acid (150g / L), and then removed the acid remaining was washed with distilled water. Then, the washed copper foil was immersed in a carboxybenzotriazole (CBTA) 5 g / L solution at 40 ° C. for 30 seconds, then taken out, washed with deionized water and washed with CBTA.
The organic release layer of No. 1 was formed. (B) Copper Electrodeposition A copper sulfate electrodeposition bath containing 250 g / L of copper sulfate and 70 g / L of sulfuric acid was used on the formed organic release layer, and the bath temperature was 4
Cathodic electrolysis was performed at 0 ° C. and a current density of 5 A / dm ² to deposit 3 μm of copper. The obtained composite copper foil was heated before and 15
The support peeling ability was evaluated by the following method both after heating at 5 ° C. for 15 minutes. Evaluation method A scotch tape was attached to an ultrathin copper foil of the composite copper foil. Then, the adhered Scotch tape was peeled off from the composite copper foil, and whether the ultra-thin copper foil adhered to the Scotch tape and separated from the copper support metal layer (whether the peeling state was acceptable).
Was observed.

The obtained results are shown in Table 2.

[0087]

Examples 9 to 12 and Reference Examples 1 and 2 Example 9
.About.12, and in Reference Examples 1 and 2, composited in the same manner as in Example 8 except that the organic layer was formed by an aqueous solution (5 g / L) of a nitrogen-containing compound or a sulfur-containing compound other than CBTA shown in Table 2. Copper foil was manufactured.

The resulting composite copper foil was evaluated in the same manner as in Example 8.

The obtained results are shown in Table 2.

[0090]

Comparative Examples 1 to 3 In each of Comparative Examples 1 to 3, Example 8 except that the organic layer was formed by an aqueous solution (5 g / L) of a nitrogen-containing compound or a sulfur-containing compound other than CBTA shown in Table 2. A composite copper foil was manufactured in the same manner as in.

The obtained composite copper foil was evaluated in the same manner as in Example 8.

The results obtained are shown in Table 2.

[0093]

Examples 13 to 15 In each of Examples 13 to 15, the organic layer was an aqueous solution of a carboxylic acid shown in Table 2 (5 g / L).
A composite copper foil was produced in the same manner as in Example 8 except that the copper foil was formed in.

The resulting composite copper foil was heated before and 180 °
The evaluation was performed in the same manner as in Example 8 except that the heating was performed at 15 ° C. for 15 minutes and then both were evaluated.

The obtained results are shown in Table 2.

[0096]

Comparative Examples 4 and 5 In each of Comparative Examples 4 to 5, a composite copper foil was produced in the same manner as in Example 8 except that the organic layer was formed from the aqueous solution of the carboxylic acid shown in Table 2 (5 g / L). did.

The support separation ability of the obtained composite copper foil was evaluated in the same manner as in Example 8 except that it was evaluated both immediately after production and after exposure to 180 ° C. for 15 minutes.

The results obtained are shown in Table 2.

[0099]

[Table 2]

[0100]

Example 16 As a support metal layer, an electrolytic copper foil having a thickness of 35 μm was prepared. An organic release layer was formed on the mat surface side in the following manner, and then copper electrodeposition, roughening treatment and rust prevention treatment were performed. The copper foil of (A) a release layer formed 35 [mu] m, and washed <br/> purification in aqueous solution of sulfuric acid (150g / L), and then removed the acid remaining was washed with distilled water. Then, the washed copper foil is immersed in a 2 g / L solution of carboxybenzotriazole (CBTA) at 30 ° C. for 30 seconds, then taken out, washed with deionized water and washed with CBTA.
The organic release layer of No. 1 was formed. (B) Copper Electrodeposition A copper sulfate electrodeposition bath containing 250 g / L of copper sulfate and 70 g / L of sulfuric acid was used on the formed organic release layer, and the bath temperature was 4
Cathodic electrolysis was performed at 0 ° C. and a current density of 5 A / dm ² to deposit 3 μm of copper. (C) Roughening treatment The surface of the ultrathin copper foil layer thus formed was subjected to a roughening treatment by a conventionally known method. The current density was increased to form conductive copper fine particles on the surface of the ultrathin copper foil. (D) Anticorrosion treatment The surface of the roughened ultrathin copper foil layer was subjected to anticorrosion treatment with zinc chromate by a conventionally known electrodeposition method to obtain a composite copper foil.

The composite copper foil thus obtained was laminated on a commercially available 0.1 mm FR-4 prepreg, and 175 ° C., 2
The copper-clad laminate was obtained by molding under heat and pressure for 60 minutes under the condition of 5 kg / cm ² .

Using this copper-clad laminate, the peel strength (A) when peeling the copper foil used as the support metal layer from the ultrathin copper foil was measured according to JIS-C-6481. It was 0.03 kgf / cm. Therefore, the copper foil of the support could be easily peeled from the copper-clad laminate, and the adhesive strength was appropriate and uniform.

Further, after peeling off the support metal layer,
The ultrathin copper foil of the copper-clad laminate was plated with copper to a thickness of 18 μm. The peel strength (B) when peeling this from the substrate was measured according to JIS-C-6481 and was 1.6 kgf / cm.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a composite copper foil according to the present invention.

FIG. 2 is a schematic cross-sectional view showing one embodiment of the composite copper foil according to the present invention.

FIG. 3 is a schematic cross-sectional view showing one embodiment of the composite copper foil according to the present invention.

FIG. 4 is a schematic cross-sectional view showing one embodiment of the composite copper foil according to the present invention.

FIG. 5 is a schematic cross-sectional view showing one embodiment of the composite copper foil according to the present invention.

[Explanation of symbols]

1 ... Composite copper foil 2 ... Support metal 3 ... Organic release layer 4 ... Ultra-thin copper foil 5 ... Copper clad laminate 6,6 '... Substrate 7 ... Printed wiring board 8, 8 '... Wiring pattern 11 ... Copper-clad laminate ..Multilayer printed wiring boards

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification FI C25D 3/38 102 C25D 3/38 102 7/06 7/06 A H05K 3/00 H05K 3/00 R (72) Inventor Cedar Akiko Oka 4-9-24-212 Suzutani, Yono City, Saitama Prefecture (72) Inventor Atsushi Yoshi Oka 3-4-148, Kashiwaza, Ageo City, Saitama 2-814 Park Ageo (56) Reference Japanese Patent Laid-Open No. 5- 138807 (JP, A) JP-A-8-1859 (JP, A) JP-A-50-86431 (JP, A) JP-A-7-231161 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05K 1/09 H05K 1/16 H05K 3/00 H05K 3/38 H05K 3/46 C25D 5/00-7/12 B32B 15/08

Claims (31)

(57) [Claims] 1. A replacement is provided between the support metal layer and the ultrathin copper foil.
Group-containing triazole compounds, mercaptobenzothia
Zole, thiocyanuric acid and 2-benzimidazole
Sulfur-containing compounds selected from thiols, as well as mono
A composite copper foil for forming a printed wiring board, which has an organic release layer made of a compound selected from the group consisting of carboxylic acids . 2. The organic release layer is formed of an organic compound that can be chemically bonded to the support metal layer and the ultrathin copper foil, and can evenly electrodeposit the ultrathin copper foil on the support. And the composite copper foil from the ultra-thin copper foil side 15
When laminated on a substrate at a temperature of 0 ° C. or higher, the peel strength (A) of the support metal layer from the ultrathin copper foil is greater than the peel strength (B) of the ultrathin copper foil from the substrate. The composite copper foil for forming a printed wiring board according to claim 1, wherein the support metal layer can be peeled off from the composite copper foil after lamination. 3. The triazole compound having a substituent is carboxybenzotriazole, N ′, N′-bis (benzotriazolylmethyl) urea or 3-amino-1H-1,2,
The composite copper foil for forming a printed wiring board according to claim 1, which is selected from the group consisting of 4-triazole. Wherein said monocarboxylic acid is oleic acid, the printed wiring board for forming a composite copper foil according to claim 1 or 2, characterized in that it is selected from the group consisting of linoleic acid and linolenic acid. Wherein said peel strength (A) is 0.005
3. It is within the range of 0.3 kgf / cm.
5. A composite copper foil for forming a printed wiring board according to any one of items 4 to 4. Wherein said support metal layer, the printed wiring board for forming a composite foil according to any one of claims 1 to 5, wherein the copper or copper alloy. Wherein said support metal layer, the printed wiring board for forming a composite foil according to any one of claims 1 to 5, wherein the copper-coated aluminum. Wherein said ultra-thin copper foil, printed circuit board for forming a composite copper foil as claimed in any one of claims 1-7, characterized in that a thickness of less than 12 [mu] m. 9. The composite copper foil for forming a printed wiring board according to claim 1, wherein the support metal layer has a thickness of 5 mm or less. Wherein said support metal layer, 18～70Myuemu
The composite copper foil for forming a printed wiring board according to claim 9, wherein the composite copper foil has the following thickness. 11. The surface of the ultrathin copper foil is subjected to a roughening treatment in order to improve the peel strength (B), according to any one of claims 2 to 10. Composite copper foil for printed wiring board formation. 12. The surface of the ultra-thin copper foil, in order to prevent oxidation, for a printed wiring board formed according to any one of claims 1 to 11, characterized in that it is rust Composite copper foil. 13. A copper-clad laminate, wherein the composite copper foil for forming a printed wiring board according to any one of claims 1 to 12 is laminated on an insulating base material. 14. The copper-clad laminate according to claim 13, wherein the support metal layer is separated from the composite copper foil of the copper-clad laminate. 15. A printed wiring board having a wiring pattern formed on the ultrathin copper foil of the copper-clad laminate according to claim 14. 16. A copper-clad laminate is formed by laminating the composite copper foil according to claim 1 on at least one surface of an inner layer plate on which a wiring pattern is formed in advance, and forming the copper-clad laminate. A multilayer printed wiring characterized in that the support metal layer is peeled off from the laminate to expose the ultra-thin copper foil, and a wiring pattern is formed on the ultra-thin copper foil to produce a multi-layer printed wiring. Board. 17. A multilayer printed wiring board formed by stacking a plurality of the printed wiring boards according to claim 15 or 16. 18. The support metal layer has a substituent.
Triazole compound, mercaptobenzothiazole, thiazole
Ocyanuric acid and 2-benzimidazole thiol
Sulfur-containing compounds selected from monocarboxylic acids
A printed wiring comprising a step of uniformly forming an organic release layer made of a compound selected from the group consisting of, and a step of electrodepositing an ultrathin copper foil layer on the organic release layer. Manufacturing method of composite copper foil for substrate formation. 19. The organic release layer is formed of an organic compound capable of being chemically bonded to the support metal layer and the ultrathin copper foil, and capable of uniformly electrodepositing the ultrathin copper foil on the support. And the composite copper foil from the ultra-thin copper foil side by 150
When laminated on a substrate at a temperature of ℃ or more, the peel strength (A) of the support metal layer from the ultrathin copper foil is higher than the peel strength (B) of the ultrathin copper foil from the substrate. 19. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, wherein the composite metal foil is small, and the support metal layer can be peeled from the composite copper foil after lamination. 20. The organic release layer is obtained by immersing the support metal layer in an aqueous solution of the organic compound to form a thin layer of the organic compound bonded to the support metal layer. 20. The method for producing a composite copper foil for forming a printed wiring board according to claim 18 or 19. 21. The triazole compound having a substituent is carboxybenzotriazole, N ′, N′-bis (benzotriazolylmethyl) urea or 3-amino-1H-1,
21. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, wherein the method is selected from the group consisting of 2,4-triazole. 22. The monocarboxylic acid is oleic acid,
21. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, wherein the method is selected from the group consisting of linoleic acid and linoleic acid. 23. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, wherein an electrolytic solution bath containing substantially no acid is used in the electrodeposition. . 24. The method for producing a composite copper foil for forming a printed wiring board according to claim 23, wherein the electrolytic solution bath contains copper cyanide or copper pyrophosphate. 25. The ultrathin copper foil has a thickness of at least 0.
It is 5 micrometers, The manufacturing method of the composite copper foil for printed wiring board formation in any one of Claims 18-24 characterized by the above-mentioned. 26. The first layer is formed by electrodepositing copper on the organic release layer formed on the support by using a primary electrolytic solution bath containing copper cyanide or copper pyrophosphate in the electrodeposition. An ultrathin copper foil is formed by forming a second layer by electrolytically depositing copper on the first layer using a secondary electrolyte bath containing copper sulfate and sulfuric acid. The method for producing a composite copper foil for forming a printed wiring board according to claim 24 or 25. 27. The first layer is at least 0.5 μm thick, and the total thickness of the first and second layers is 12.
27. The method for producing a composite copper foil for forming a printed wiring board according to claim 26, wherein the method is not more than μm. 28. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, wherein an electrolytic solution bath containing copper sulfate and sulfuric acid is used in the electrodeposition. 29. The method for producing a composite copper foil for forming a printed wiring board according to claim 18, further comprising a step of roughening the surface of the ultrathin copper foil. . 30. The method for producing a composite copper foil for forming a printed wiring board according to claim 29, further comprising a step of subjecting the surface of said ultrathin copper foil to rust prevention treatment. 31. The method according to claim 30, wherein the anticorrosion treatment includes a step of electrodepositing at least one selected from the group consisting of zinc, zinc chromate, nickel, tin, cobalt and chromium. A method for manufacturing a composite copper foil for forming a printed wiring board.