JP2003041333A - Copper alloy foil for laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy foil with small surface roughness, high electroconductivity, and high strength, which has adequate adhesiveness to an adhesive containing an epoxy resin without being roughened, and can be laminated to a copper-clad laminate, in a three-layer flexible substrate. SOLUTION: The copper alloy foil for the laminate is characterized by including particular elements, by making the thickness of the rust preventive film to be 3 nm or less from the surface, to impart the surface adequate adhesiveness to the adhesive containing the epoxy resin, by having surface roughness of 2 μm or less according to ten-points average surface roughness (Rz), and by having 180 degree peel strength of 8.0 N/cm or more when bonded to a substrate film with the adhesive containing the epoxy resin, without being roughened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy foil used for a laminated board for a printed wiring board.

[0002]

2. Description of the Related Art Printed wiring boards are often used in electronic circuits of electronic equipment. The printed wiring board is roughly classified into a hard laminated board (rigid board) and a flexible laminated board (flexible board) depending on the type of resin as a base material. The flexible substrate is characterized by its flexibility, and besides being used for the wiring of movable parts, it can also be stored in a bent state in electronic devices, so it is also used as a space-saving wiring material. There is. Since the substrate itself is thin, it is also used as an interposer for semiconductor packages or as an IC tape carrier for liquid crystal displays. A polyimide resin film or a polyester resin film is used as the base material of the flexible substrate, but currently polyimide is often used from the viewpoint of heat resistance. Copper is generally used as the conductive material of the flexible substrate from the viewpoint of conductivity. The printed wiring board is formed by etching the copper foil of the copper clad laminate to form various wiring patterns and connecting electronic components with solder to mount them.

Flexible substrates include two-layer flexible substrates and three-layer flexible substrates due to their structure. The two-layer flexible substrate has a structure in which a resin such as polyimide and copper serving as a conductive material are directly bonded. On the other hand, the three-layer flexible substrate has a structure in which a resin film such as polyimide and a copper foil serving as a conductive material are bonded with an adhesive containing an epoxy resin, an acrylic resin, or the like, but the adhesiveness is good. It is widely used because it is inexpensive. Due to such a difference in structure, the resin bonded to copper in the flexible substrate is the resin contained in the adhesive in the three-layer flexible substrate, whereas the two-layer flexible substrate is polyimide.

Since the adhesive used for the three-layer flexible substrate needs characteristics such as heat resistance, durability and flexibility, various resins are mixed to adjust the strength and the glass transition temperature. However, those containing an epoxy resin as a main component are generally used. The adhesive used for this purpose is a solvent-like or sheet-like adhesive containing an epoxy resin (for example, bisphenol A type glycidyl ether or glycidyl ester type epoxy resin) as a curing agent such as amine, and nitrile rubber or elastomer for imparting flexibility. To be The method for producing a copper-clad laminate is generally a method in which a solvent-like adhesive is applied onto a polyimide film and then a copper foil is laid over it where it is dried, or the adhesive is formed into a sheet between the polyimide film and the copper foil. It is sandwiched between objects and temporarily adhered by a roll press machine or a plane heating press machine, and then heat cured at 100 to 200 ° C. for several tens of minutes to several hours to adhere.

When a printed wiring board is mounted by connecting electronic components with solder, thermal stress is applied due to the difference in thermal expansion coefficient between the copper foil and the resin, so that the adhesiveness between the copper foil and the resin is poor. The problem of peeling occurs. For this reason, the copper foil used in the copper-clad laminate has been subjected to a roughening treatment in which copper particles are formed on the surface of the copper foil by electroplating in order to improve the adhesion with the resin. This is to improve the adhesiveness by a so-called anchor effect, in which unevenness is formed on the surface of the copper foil and the copper foil is made to dig into the resin to obtain mechanical adhesive strength. On the other hand, as electronic devices have become smaller, lighter and more sophisticated in recent years, the demand for high-density mounting on printed wiring boards has increased,
Fine pitches are being made by reducing the wiring width and spacing of electronic circuits. When a copper foil with a large surface roughness or a copper foil that has been roughened by a roughening treatment is used as the conductive material, etching residue may remain in the resin when etching the circuit, or the etching linearity may deteriorate. Then, the circuit width tends to be uneven. Therefore, in order to make the electronic circuit finer, it is preferable that the surface roughness of the copper foil is small. In electronic devices such as personal computers and mobile communications, the frequency of electric signals is high, but the frequency of electric signals is 1G.
When the frequency is higher than Hz, the effect of the skin effect in which the current flows only on the surface of the conductor becomes remarkable, and the effect of changing the transmission path due to the unevenness of the surface cannot be ignored. Therefore, attempts have been made to reduce the surface roughness of the copper foil due to the high frequency characteristics.

Copper foil which is a conductive material of a printed wiring board is classified into electrolytic copper foil and rolled copper foil depending on the manufacturing method. Electrolytic copper foil is generally manufactured by electrolytically depositing copper from a sulfuric acid-acidified copper sulfate plating bath on a titanium or stainless steel drum. When electrolytically depositing, irregularities are formed on the copper foil and the surface roughness increases. Recently, adding additives to the plating bath,
A copper foil, a so-called low profile foil, whose surface roughness is reduced by adjusting electrolytic deposition conditions has come to be manufactured. Since the rolled copper foil is manufactured by plastic working with a rolling roll, a smooth surface in which the surface morphology of the rolling roll is transferred to the surface of the foil can be obtained. The foil is generally 100μ.
A thin plate having a thickness of m or less.

As described above, the copper foil currently used in the copper-clad laminate is currently subjected to a roughening treatment in order to improve the adhesiveness with the resin. For the above reasons, the roughening treatment is performed. It is desirable to bond a copper foil having a small surface roughness that is not applied to the resin film, and it is necessary to secure adhesive strength without performing a roughening treatment. Further, in a three-layer flexible substrate, an attempt has been made to apply a silane coupling agent or the like to the copper foil in order to improve the adhesive strength between the copper foil that is a metal and the adhesive that is an organic substance, but sufficient adhesiveness is not obtained. Has not been done.

The material of the copper foil used as the conductive material is
Pure copper or a copper alloy containing a small amount of additional elements is used. Copper foil, which is a conductor, has become thinner and the circuit width has become narrower as the pitch of electronic circuits has become finer. ing. Copper is a material with excellent conductivity,
In the above fields where conductivity is important, pure copper having a purity of 99.9% or more is generally used. However, since the strength of copper decreases as the purity increases, the handling property deteriorates when the copper foil becomes thin. Therefore, the strength of the copper foil is preferably high.

Under these circumstances, an attempt was made to bond the polyimide film to the polyimide film using an adhesive containing an epoxy resin, without subjecting the copper foil as a conductive material to roughening treatment. However, it has been found that the polyimide film and the rolled copper foil of pure copper are easily separated, and the interface between the adhesive containing the epoxy resin and the copper is easily separated. For this reason, using a copper foil as a conductive material without subjecting it to roughening treatment tends to cause peeling of the copper foil from the epoxy resin, which is the main component of the adhesive, resulting in a problem such as disconnection. , Has not been put to practical use.

[0010]

To improve the adhesiveness when a three-layer printed wiring board is manufactured by bonding a polyimide resin film as a base material and a copper foil as a conductive material with an adhesive containing an epoxy resin. A copper alloy for a laminated plate, which can obtain a surface roughness of a copper foil of 2 μm or less in Rz and a bonding strength of 8.0 N / cm or more in a 180 ° peel strength without performing a special treatment such as a roughening treatment. Is to provide foil.

[0011]

The inventors of the present invention have investigated the adhesiveness when a polyimide resin film and a copper foil of a conductive material are bonded together with an adhesive containing an epoxy resin, and as a result, the adhesiveness is conductive. It has been found that the improvement is achieved by a copper alloy with a small amount of additional elements based on pure copper having excellent properties, and that it is reduced as the rustproof coating of the copper alloy foil becomes thicker.
Specifically, as a result of repeated studies on the influence of various additive elements on the adhesiveness with an adhesive containing an epoxy resin and the relationship between the thickness of the rust-preventive coating and the adhesiveness, the present invention was The content of Ag is 0.02% by mass to 1.0% by mass, In is 0.01% by mass to 0.5% by mass, and one or more of the respective components are included, and the balance is copper and unavoidable. The surface roughness is 10-point average surface roughness (R
z) 2 μm or less, conductivity 80% IACS or more, no roughening treatment required, and 180 ° peel between the adhesive containing epoxy resin and the copper alloy foil when bonded to the substrate resin with the adhesive containing epoxy resin. A copper alloy foil for a laminate, which has a strength of 8.0 N / cm or more. (2) Ag containing 0.02% by mass to 1.0% by mass and In containing 0.01% by mass to 0.5% by mass of the components of the additional element, and at least one of these components, Furthermore, Al, Be,
Co, Fe, Mg, Mn, Ni, P, Pb, Si, Ti
And 0.001 to 2.5 mass% of one or more of the respective components of Zn and Zn in total, and the balance consisting of copper and unavoidable impurities, and the thickness of the rust preventive film being 3 nm or less from the surface The surface roughness is 10 μm or less in terms of ten-point average surface roughness (Rz), the tensile strength is 500 N / mm ² or more, the electrical conductivity is 60% IACS or more, and the roughening treatment is unnecessary, and the epoxy resin is contained. A copper alloy foil for laminates, wherein the 180 ° peel strength between the adhesive containing the epoxy resin and the copper alloy foil is 8.0 N / cm or more when bonded to the substrate resin with the adhesive.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The reason why the surface condition and alloy composition are limited to the above in the present invention will be described. (1) Anticorrosion coating: To prevent discoloration of pure copper and copper alloys, it is widely used to form a chelate with copper on the surface by using an organic substance containing nitrogen such as benzotriazole or imidazole to form an anticorrosion coating. It is being appreciated. On the other hand, these rust-proof coatings have water repellency and have an effect of impairing the bonding of the epoxy resin to deteriorate the adhesiveness. Therefore, by limiting the thickness of the rust-preventive coating to 3 nm or less from the surface, it becomes possible to firmly bond the copper alloy foil and the polyimide film using an adhesive containing an epoxy resin. In order to reduce the thickness of the rust preventive film, for example, there is a method of reducing the concentration of the rust preventive agent. When benzotriazole is used as the rust preventive agent, the concentration is preferably 3000 ppm or less. The thickness of the anticorrosion coating from the surface can be quantified by measuring by Auger electron spectroscopy.
That is, by Auger electron spectroscopy analysis, analysis is performed in the depth direction, and the depth from the surface until the detected intensity of nitrogen, which is an element constituting the rust preventive agent, becomes the same as the background, is measured in terms of SiO _2. Required by

(2) Ag, In: It is known that Ag and In act as a catalyst for promoting polymerization when a resin is produced. Therefore, it is considered that by adding Ag and In to copper to form an alloy foil, the bonding between the metal and the epoxy resin which is the main component of the adhesive is promoted and the bonding at the interface is strengthened. However, if the added amounts of Ag and In are too small, they do not sufficiently act as a catalyst, so that the metal and the resin are not sufficiently bonded and the effect of improving the adhesiveness is small. Practical use as a printed wiring board 1
It is necessary to impart a strength of 8.0 N / cm or more, which is a 80 ° peel strength. To obtain this characteristic, Ag,
The added amount of In is 0.02% by mass or more in weight ratio, and 0.1.
It was found to be 01 mass% or more. Also, Ag, I
n is a solid solution in copper to improve heat resistance, Ag, In
The copper alloy foil containing a small amount of silver is suitable as a conductive material because it has a small effect on conductivity. However, A added to copper
If the amounts of g and In increase, the conductivity decreases and it becomes unsuitable as a conductive material for circuits. Therefore, as a result of studying a suitable composition as a copper alloy foil for a laminated board of a printed wiring board, as a result, Ag is 0.02 to 1.0% by mass, more preferably 0.04 to 0.5% by mass, and In is In. Is 0.0
It has been found to be 1 to 0.5% by weight, more preferably 0.02 to 0.3% by weight.

(3) Tensile strength and electroconductivity: In general, strength and electroconductivity are in a contradictory relationship, and the higher the strength of the material, the lower the electroconductivity tends to be. Therefore, for those requiring high electrical conductivity, high electrical conductivity is required even if the strength is poor, so the electrical conductivity was defined as 80% IACS.
On the other hand, if the tensile strength is less than 500 N / mm ² , wrinkles are likely to occur during handling such as handling, so if the tensile strength is high, the electrical conductivity will be low and 60% IAC
In the case of S or less, it is not preferable as a conductive material for laminated plates. Tensile strength is 500 N / mm ² as a condition suitable for a copper alloy foil for a laminated plate having high strength and excellent handleability.
As described above, the conductivity is determined to be 60% IACS or more. (4) Al, Be, Co, Fe, Mg, Mn, Ni,
P, Pb, Si, Ti and Zn are all mainly
It has the effect of increasing the strength of the copper alloy, and if necessary, one or more kinds of additives are added. The total content is 0.
If the amount is less than 005% by mass, the desired effect cannot be obtained, while if the total amount exceeds 2.5% by mass, the conductivity, solderability and workability are significantly deteriorated. Therefore, Al, Be, Co, Fe, Mg, Mn, Ni,
The total content of P, Pb, Si, Ti and Zn was set to 0.005 to 2.5 mass%.

(5) Surface roughness: When the surface roughness of the copper foil increases, the impedance increases due to the skin effect in which the current flows only on the surface of the conductor when the frequency of the electric signal is 1 GHz or more, and the high frequency signal is transmitted. Affect. Therefore, it is necessary to reduce the surface roughness in the use of conductive materials for high-frequency circuits.As a result of studying the relationship between surface roughness and high-frequency characteristics, the surface roughness of copper alloy foil for laminated boards of printed wiring boards It was found that the ten-point average surface roughness (Rz) should be 2 μm or less. As a method for reducing the surface roughness, there are methods such as optimizing the manufacturing conditions of rolled copper foil and electrolytic copper foil, and chemically polishing or electrolytic polishing the surface of the copper foil. In general, rolled copper foil can easily reduce the surface roughness, and it is possible to reduce the surface roughness of the work roll of the rolling mill to reduce the profile of the work roll transferred to the copper foil. it can. (6) 180 ° peel strength: When the 180 ° peel strength is small, peeling may occur from the laminated plate.
An adhesive strength of 0 N / cm or more is required.

The copper alloy foil of the present invention is not limited to a manufacturing method, and can be manufactured by a method such as electrolytic copper foil by an alloy plating method or a rolled copper foil in which an alloy is melt cast and rolled. The rolling method will be described below as an example. A predetermined amount of alloying element is added to molten pure copper and cast in a mold to form an ingot. The melting and casting of the copper alloy is preferably performed in a vacuum or in an inert gas atmosphere in order to suppress the formation of oxides and the like. It is desirable to use electrolytic copper or oxygen-free copper having a low oxygen content as the raw material. The ingot is thinned to a certain thickness by hot rolling, then cut, then repeatedly cold-rolled and annealed, and finally cold-rolled to obtain a foil. Rolling oil adheres to the material after rolling, so
Degrease with acetone or petroleum solvent.

If an oxide layer is formed by annealing, it will interfere with the subsequent steps. Therefore, it is necessary to perform the annealing in vacuum or in an inert gas atmosphere, or to remove the oxide layer after annealing.
For example, in order to remove the oxide layer by pickling, it is preferable to use sulfuric acid + hydrogen peroxide, nitric acid + hydrogen peroxide, or sulfuric acid + hydrogen peroxide + fluoride.

[0018]

EXAMPLES Examples of the present invention will be described below. A copper alloy was prepared by melting oxygen-free copper as a main material in a high-purity graphite crucible in an Ar atmosphere using a high-frequency vacuum induction melting furnace, and then using silver, indium, aluminum, or copper beryllium as auxiliary materials. Mother alloy, cobalt, copper iron mother alloy,
Magnesium, manganese, nickel, copper phosphorus master alloy,
After adding an additive element selected from lead, copper-silicon master alloy, titanium and zinc, it was cast in a cast iron mold. With this method, thickness 30mm, width 50mm, length 150mm,
A copper alloy ingot weighing about 2 kg was obtained. This ingot is heated to 900 ° C and hot rolled to a thickness of 8 mm.
After removing the oxide scale by rolling up to 80 ° C., cold rolling and heat treatment were repeated to obtain a rolled copper alloy foil with a thickness of 35 μm.

Since the rolling oil adhered to the copper alloy foil having a thickness of 35 μm obtained by the above method, it was immersed in acetone to remove the oil. This was immersed in an aqueous solution containing 10% by weight of sulfuric acid and 1% by weight of hydrogen peroxide to remove the oxide layer and the rust preventive film on the surface. For the purpose of investigating the influence of the thickness of the rust preventive film, the film was immersed in an aqueous solution in which the concentration of benzotriazole was adjusted and immediately dried. Other than this, no special surface treatment such as roughening treatment or silane coupling treatment for improving adhesiveness is carried out. The copper alloy foil thus prepared was bonded to a polyimide film with an adhesive containing an epoxy resin to prepare a copper clad laminate. The copper-clad laminate is prepared by coating a solvent-type adhesive, which is a mixture of an epoxy resin and a curing agent, on a polyimide film having a thickness of 25 μm with an applicator having a gap amount of 100 μm, and the temperature is 130 ° C. in a dryer. After drying for 4 minutes, the above-mentioned copper alloy foils were overlaid and held for 30 minutes under the conditions of a temperature of 170 ° C. and a pressure of 30 kgf / cm ² using a flat heating press to obtain a copper-clad laminate. Here, the thickness of the adhesive after drying is 20 μm.
Met.

The "tensile strength", "electrical conductivity", "thickness of rust preventive film", "surface roughness", "high frequency characteristics" and "adhesive strength" of the copper alloy foil thus obtained are as follows. It evaluated by the method. (1) Tensile strength: Tensile strength was measured by measuring the tensile strength at room temperature by a tensile test. The measurement sample is a copper foil processed to a thickness of 35 μm, and a width of 12.7 m using a precision cutter.
m and 150 mm in length were cut into strips. This was measured at a distance between scores of 50 mm and a tensile speed of 50 mm / min. (2) Conductivity: The conductivity was obtained by measuring the electric resistance at 20 ° C. by a DC four-terminal method using a double bridge. As the measurement sample, a copper foil processed into a foil having a thickness of 35 μm was cut into a width of 12.7 mm. The electrical resistance was measured by measuring the electrical resistance of this for a measurement length of 50 mm. (3) Thickness of rust preventive film: As described above, the depth direction analysis of Auger electron spectroscopic analysis was performed, and from the surface until the detected intensity of nitrogen, which is an element that constitutes the rust preventive agent, became the same as the background. Was measured in terms of SiO ₂ . (4) Surface roughness: The surface roughness was measured in the direction perpendicular to the rolling direction using a stylus type surface roughness meter. Measurement conditions are JI
The ten-point average surface roughness (Rz) was evaluated according to the method described in S B 0601. (5) High frequency characteristics: The high frequency characteristics were evaluated by the impedance when a high frequency current was applied. For impedance, copper foil processed to a thickness of 35 μm was processed to a width of 1 mm, and 1
The voltage drop when a high frequency current of 0 MHz and 20 mA was applied was measured for a length of 100 mm. (6) Adhesive strength: Adhesive strength is 180 ° peel strength JI
It was carried out according to the method described in S C 5016. The width of the peeling conductor is 5.0 mm, the polyimide film side is fixed to the tensile tester side, the copper alloy foil that is the conductor is bent in the 180 ° direction, and the pulling speed is 50 mm.
It was peeled off at the speed of / min.

An embodiment according to claim 1 of the present invention will be shown.
Table 1 shows the composition of the copper alloy foil, and Table 2 shows the results of its characteristic evaluation. In addition, the part shown by "-" in the table indicates that the measurement is not performed. No. of the embodiment. 1-No.
9 is an example of the copper alloy foil according to claim 1 of the present invention. The electrical conductivity of the copper alloy foil of the present invention is 80% IACS or more, and the 180 ° peel strength when the copper alloy foil is bonded to a polyimide film with an adhesive containing an epoxy resin is 8.0 N / cm or more. . It can be seen that it has excellent conductivity and high adhesive strength.

[0022]

[Table 1]

[0023]

[Table 2]

Next, an embodiment according to claim 2 of the present invention will be described. Table 3 shows the composition of the copper alloy foil, and Table 4 shows the characteristic evaluation results. No. of the embodiment. 10-No. 14 is an example of the copper alloy foil according to claim 2 of the present invention. As shown in Table 4, the copper alloy foil of the present invention has a conductivity of 60% IAC.
The tensile strength is S or more, the tensile strength is 500 N / mm ² or more, and the 180 ° peel strength is 8.0 N / cm when a copper alloy foil is bonded to a polyimide film with an adhesive containing an epoxy resin.
That was all. It can be seen that it has excellent conductivity and handleability, and also has high adhesive strength.

[0025]

[Table 3]

[0026]

[Table 4]

Table 5 shows the composition of the copper alloy foil of Comparative Example and Table 6
Is the characteristic evaluation result. No. 15 to 19 are comparative examples relating to claim 1 of the present invention. No. Reference numeral 15 is a rolled copper foil to which the alloy component of the present invention is not added. An ingot obtained by melting and casting oxygen-free copper in an Ar atmosphere was processed into a foil, and the foil was bonded under the same conditions as the polyimide film using the same adhesive as in the example. Since the material is pure copper, it has high conductivity, but its 180 ° peel strength is as small as 7.5 N / cm and sufficient adhesive strength is not obtained, so peeling may occur when it is used as a printed wiring board.

[0028]

[Table 5]

[0029]

[Table 6]

No. 16-No. No. 19 was processed into a foil by adding Ag or In in the same manner as in the example.
No. No. 16, which has a high Ag concentration, has a large electric conductivity, but the effect of improving heat resistance and adhesiveness is not sufficient.
The 180 ° peel strength is low and there is a risk of peeling when processed into a laminated plate. On the other hand, No. No. 17 was added because the concentration of Ag was more than 1.0% by mass in weight ratio.
Although it has a high 80 ° peel strength, it has a low conductivity of less than 80% IACS and is not suitable as a conductive material for a printed wiring board which requires high conductivity. Similarly, No. Since No. 18 has a low In concentration, it has a high conductivity, but the effect of improving heat resistance and adhesiveness is not sufficient. No. 19 was added because the concentration of In exceeds 0.5 mass% by weight,
The electrical conductivity is as low as less than 80% IACS, which is not suitable as a conductive material for a printed wiring board that requires high electrical conductivity.

No. 20 and 21 are comparative examples relating to claim 2 of the present invention. No. No. 20 contains Ni and P in addition to Ag, and No. 20. No. 21 was processed into a foil by adding Ti in addition to In and by the same method as in the example. However, the addition amount of P or Ti increases the tensile strength and improves heat resistance and adhesiveness, but if the addition amount of P or Ti exceeds 2.5 mass% by weight, the conductive property is increased. Rate is 60
It is much lower than% IACS, and is not suitable as a conductive material for a printed wiring board.

No. 22 is N of the embodiment shown in Table 1.
o. The alloy foil of No. 3 was used to lightly scrape the surface with emery paper to roughen the surface. As a result, when the surface roughness becomes large, the impedance increases due to the skin effect when energized at a high frequency, which is not suitable as a conductive material for a high frequency circuit.

No. of the comparative example. No. 23 of the embodiment shown in Table 1 Using the alloy foil of No. 3, it was immersed in an aqueous solution in which the concentration of benzotriazole as a rust preventive was adjusted to 0.5% (5000 ppm). Due to the high concentration of the rust preventive agent, the thickness of the rust preventive film becomes as thick as 5 nm
The 80 ° peel strength is as low as 4.5 N / cm.

[0034]

When the copper alloy foil of the present invention is used for a printed wiring board laminate by adhering it to a polyimide resin film using an adhesive containing an epoxy resin, it has excellent adhesion to the resin even if the surface roughness is small. And has high conductivity and strength. This makes it suitable for use as a conductive material for electronic circuits that require fine wiring.

Claims (2)

[Claims] 1. Ag is 0.02% by mass to 1.0% by mass and In is 0.01% by mass in terms of the weight ratio of the additive element components.
.About.0.5% by mass of each component, the balance consisting of copper and unavoidable impurities, and the thickness of the rust preventive film being 3 nm or less from the surface, the surface roughness is 10-point average surface. Roughness (Rz) is 2 μm or less, conductivity is 80% IACS
As described above, the roughening treatment is not necessary, and the 180 ° peel strength between the adhesive containing the epoxy resin and the copper alloy foil is 8.0 N / cm or more when the substrate resin is joined with the adhesive containing the epoxy resin. Characteristic, copper alloy foil for laminated boards. 2. Ag is 0.02% by mass to 1.0% by mass and In is 0.01% by mass in terms of the weight ratio of the additive element components.
.About.0.5% by mass of each component, and further includes A
l, Be, Co, Fe, Mg, Mn, Ni, P, Pb,
It contains 0.005 mass% to 2.5 mass% of one or more of the respective components of Si, Ti and Zn in the total amount, and the balance consists of copper and unavoidable impurities, and the thickness of the rust preventive film is 3 from the surface.
When the surface roughness is 10 nm or less, the ten-point average surface roughness (Rz) is 2 μm or less, and the tensile strength is 500 N / mm ^2.
As described above, the electrical conductivity is 60% IACS or more, the roughening treatment is not necessary, and when the adhesive containing the epoxy resin is bonded to the substrate resin, the adhesive containing the epoxy resin and the copper alloy foil 18
A copper alloy foil for a laminate, which has a 0 ° peel strength of 8.0 N / cm or more.