JP2003064431A - Copper alloy foil for laminate sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy foil for a laminate sheet which has excellent adhesion with a liquid crystal polymer in a printed circuit board having a resin substrate of a liquid crystal polymer. SOLUTION: In a copper alloy containing specified elements, by controlling the thicknesses of an oxidized layer as an outermost surface layer and a rust preventive layer, the copper alloy foil for the laminate sheet having excellent strength and electric conductivity, and having >=5.0 N/cm 180 deg. peel strength with a liquid crystal polymer, without undergoing roughening treatment, is provided.

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. A printed wiring board is a rigid laminated board (rigid board) that uses a glass epoxy board and a paper phenol board as constituent materials, depending on the type of resin used as the base material.
And a flexible laminated plate (flexible substrate) including a polyimide substrate and a polyester substrate as constituent materials. Copper foil is mainly used as a conductive material for a printed wiring board, but the copper foil is classified into an electrolytic copper foil and a rolled copper foil depending on the manufacturing method. The electrolytic copper foil is manufactured by electrolytically depositing copper on a titanium or stainless steel drum from a copper sulfate plating bath. Since the rolled copper foil is manufactured by plastic working with a rolling roll, the surface morphology of the rolling roll is transferred to the surface of the foil, and a smooth surface is obtained.
The foil generally means a thin plate having a thickness of 100 μm or less.

A printed wiring board is formed by laminating a resin substrate and a copper foil with an adhesive and then curing the adhesive by heating and pressing. Of the above-mentioned printed wiring boards, conventionally, polyimide resin films and polyester resin films have been mainly used as resin substrates of flexible substrates. A rolled copper foil is mainly used as the copper foil used for the conductive material of the flexible substrate because of its good flexibility.

An adhesive made of a thermosetting resin such as epoxy is used for bonding the copper foil and the resin, and the adhesive is heated and pressed at a temperature of 130 to 170 ° C. for 1 to 2 hours after the bonding. Cure. Next, the copper foil is etched to form various wiring patterns, and electronic components are connected by soldering and mounted. Since the material for the printed wiring board is repeatedly exposed to such a high temperature, heat resistance is required. In recent years, lead-free solder has come to be used due to environmental considerations, but the melting point of the solder has increased, and printed wiring boards are required to have high heat resistance. Polyimide resins, which have better heat resistance than polyester, are used. Widely used.

The flexible substrate is characterized in that it has flexibility, and besides being used for wiring of a movable part, it can be housed in a bent state in an electronic device, so that it can be used as a space-saving wiring material. It is used. 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. In these applications, due to the demand for high-density mounting, fine pitches are being made by reducing the wiring width and wiring interval of electronic circuits. However, polyimide resin, which is widely used for flexible substrates, has hygroscopicity, and if it is not handled dry after laminating copper foil by heating and pressing, it may absorb moisture in the atmosphere and deform. . Therefore, a printed wiring board using a polyimide resin has a problem of dimensional stability in response to the recent demand for finer pitch. Also, electric signals are becoming high frequency in personal computers and mobile communication,
In order to cope with this, a resin substrate having a small relative dielectric constant is required.

In order to meet the demand for resin substrates used for such printed wiring boards, adoption of liquid crystal polymers is being studied. Liquid crystal polymer is one of super engineering plastics, and there are a thermotropic type (heat melting type) and a lyotropic type (solution type). Thermotropic type is used for printed wiring boards. This type of liquid crystal polymer is characterized by having high strength and chemical resistance, lower hygroscopicity than polyimide, and excellent dimensional stability. Further, the liquid crystal polymer has a relative dielectric constant of about 3.0, which is smaller than about 3.5 of polyimide, and is suitable for a resin substrate for high frequency applications. Although the liquid crystal polymer is an aromatic polyester-based thermoplastic resin, it has excellent heat resistance and can be soldered. On the other hand, since the liquid crystal polymer is softened by heating above the melting point, it is possible to bond the copper foil and the liquid crystal polymer, which are conductive materials, by heat and pressure by heat fusion without using an adhesive. is there.

By the way, at present flexible printed wiring
The coefficient of thermal expansion of the polyimide resin widely used for the board is
2.7 x 10^-5/ ° C, the coefficient of thermal expansion of copper 1.6 x
10 ^-5Since it is different from / ° C,
Warpage is likely to occur. On the other hand, the liquid crystal polymer molecules are slender
Although it is a rod shape, the coefficient of thermal expansion differs between the major axis direction and the minor axis direction.
It has the characteristic of becoming. From this property, liquid crystal polymer
By controlling the molecular orientation of the liquid crystal polymer
It is possible to adjust the coefficient of thermal expansion. Liquid crystal polymer
The coefficient of thermal expansion of the same as that of the conductive material copper.
By doing so, it is possible to reduce the difference in dimensional change during heating.
As a result, the printed wiring board is less likely to warp. liquid crystal
It is also possible to bond the polymer and copper foil with an adhesive.
However, liquids with different coefficient of thermal expansion
Between the crystalline polymer and the copper foil impairs dimensional stability.
It will be bad. High dimensional stability of printed wiring boards
To maintain, glue the liquid crystal polymer and copper foil directly
Preferably.

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. In addition, since liquid crystal polymers for printed wiring boards are required to have soldering heat resistance, the melting point is 250 ° C to 3 ° C.
A material as high as 50 ° C is used. In order to bond the copper foil and the liquid crystal polymer to each other by heat fusion, a heat treatment near the melting point of the liquid crystal polymer is required, so that the copper foil is softened and the handling property is deteriorated. Therefore, the copper foil is 30
It is preferable that heat treatment at 0 ° C. for about 1 hour does not cause softening. In addition, as the pitch becomes finer, a material excellent in etching property is required. Copper foil with a large surface roughness or copper foil with irregularities formed by roughening treatment has an etching residue left on the resin when the circuit is formed by etching, or the etching linearity decreases and the circuit width decreases. It tends to be uneven. Therefore, in order to make the electronic circuit fine pitch, it is preferable that the surface roughness of the copper foil is small,
It is desirable to bond a copper foil with a small surface roughness that has not been roughened to a resin film.

Under such circumstances, it has been attempted to bond the liquid crystal polymer as a resin substrate of a laminated plate by heat-sealing copper foil as a conductive material without using an adhesive.
However, the liquid crystal polymer film and the rolled copper foil,
Using a heating press or heating roller, pressurizing while maintaining the temperature above the melting point of the liquid crystal polymer and pasting by heat fusion, the liquid crystal polymer and the rolled copper foil of pure copper have poor adhesion and are easily peeled off. It turns out.

[0010]

In order to put into practical use a laminate for which a liquid crystal polymer and a copper foil are bonded together, it is a subject to improve the adhesiveness and handleability. The handling properties required for the production of laminates vary depending on the production conditions, but the greater the tensile strength of the copper alloy foil, the more preferable it is, but generally strength and conductivity are in a contradictory relationship, and the higher the strength of the material, the lower the conductivity. Tend to do. Although the adhesive strength required for the printed wiring board varies depending on the manufacturing conditions of the electronic equipment and the environment in which it is used, it is generally possible to put it into practical use if the 180 ° peel strength is 5.0 N / cm or more. An object of the present invention is to provide a copper foil for a laminated plate, which has excellent adhesiveness to a liquid crystal polymer and tensile strength.

[0011]

The present inventors have found that the adhesion with a liquid crystal polymer is improved by a copper alloy having a small amount of additive element based on pure copper having excellent conductivity. . Specifically, as a result of repeated studies on the influence of various additive elements on the adhesiveness to liquid crystal polymers and the conductivity, the present invention shows that (1) the additive element is contained in a weight ratio of Ag of 0.0
3% by mass to 1.0% by mass, In is 0.01% by mass to 0.
5% by mass of each component, the balance consisting of copper and unavoidable impurities, the thickness of the oxide layer of the outermost layer being 10 nm or less from the surface, and the thickness of the rust preventive film being 5 nm or less from the surface. Therefore, the conductivity is 80% IACS or more,
When liquid crystal polymer is heat-sealed without roughening treatment 1
A copper alloy foil for a laminate, which has an 80 ° peel strength of 5.0 N / cm or more. (2) Ag is 0.0 in the weight ratio of the additive element components.
3% by mass to 1.0% by mass, In is 0.01% by mass to 0.
5% by mass of one or more of each component, Al, B
e, Co, Fe, Mg, Mn, Ni, P, Pb, Si,
The total amount of one or more of the Ti and Zn components is 0.00
5% by mass to 2.5% by mass, the balance consisting of copper and unavoidable impurities, and the thickness of the oxide layer of the outer surface layer is 10 from the surface.
nm or less, and the thickness of the rust preventive film is 5 nm or less from the surface, the tensile strength is 500 N / mm ² or more, the conductivity is 60% IACS or more, and the liquid crystal polymer is heated without roughening treatment. 180 ° peel strength when fused 5.
A copper alloy foil for a laminated board, which is 0 N / cm or more. (3) The temperature at which the tensile strength when heated for 1 hour is intermediate between the tensile strength before heating and the tensile strength when softened is 300 ° C. or higher (1) or The copper alloy foil for laminated plates according to (2). Is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The reason why the alloy composition and the like are limited to the above in the present invention will be described. (1) Ag, In: Ag, In is known to act as a catalyst for promoting polymerization when a resin is produced. Therefore, it has been found that Ag and In are added to copper to form an alloy foil to improve the adhesiveness with the liquid crystal polymer. The reason is considered that Ag and In promoted the bond between the metal and the resin, and the bond at the interface was strengthened.
If the content of these components is too small, they do not act sufficiently as a catalyst, so that the metal and resin are not sufficiently bonded and the effect of improving the adhesiveness is small. In order to provide a 180 ° peel strength of 5.0 N / cm or more, which is necessary for practical use as a printed wiring board, the addition amount of Ag is at least 0.03 mass% by weight, and In is 0.01. It must be at least mass%. Further, Ag and In form a solid solution in copper to improve heat resistance, and the influence of Ag and In on the conductivity is small, and a copper alloy foil containing a small amount of silver is suitable as a conductive material. However, Ag and In added in copper
If the amount of is large, the conductivity decreases and it becomes unsuitable as a conductive material for circuits. Therefore, as a result of studying an appropriate composition as a copper alloy foil for a laminated board of a printed wiring board, Ag is 0.02% by mass to 1.0% by mass, and more preferably 0.04% by mass to 0.1% by mass. 5% by mass, In is 0.01% by mass to 0.5% by mass, and more preferably 0.02% by mass.
It was found to be 0.2% by weight.

(2) 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%.
In the case of IACS or less, it is not preferable as a conductive material for laminated plates. As a condition suitable for a copper alloy foil for a laminated plate having high strength and excellent handleability, a tensile strength is 500 N /
The conductivity was defined as mm ² or more and the electrical conductivity was 60% IACS or more. (3) Al, Be, Co, Fe, Mg, Mn, Ni,
P, Pb, Si, Ti and Zn: Ag, In have the effect of increasing the strength of the copper alloy, but especially when high strength is required from the viewpoint of handleability, the addition of a third element is effective. Target. Al, Be, Co, Fe, M
All of g, Mn, Ni, P, Pb, Si, Ti and Zn have an effect of enhancing the strength of the copper alloy mainly by solid solution strengthening, and one or more kinds thereof are added if necessary. If the total content is less than 0.005% by mass, the desired effect cannot be obtained in the above-mentioned action, while if the total content exceeds 2.5% by mass, the conductivity, solderability,
Remarkably deteriorates workability. Therefore, Al, Be, C
The total content of o, Fe, Mg, Mn, Ni, P, Pb, Si, Ti and Zn is 0.005 mass% to
It was determined to be 2.5% by mass.

(4) Oxidation layer, anticorrosion film: It has been found that the adhesion between the liquid crystal polymer and the copper alloy is improved by controlling the thickness of the oxidation layer and anticorrosion film. Conventionally, an adhesive made of a thermosetting resin such as epoxy as shown in FIG. 2 has been used for pasting a copper foil and a resin. However, adhesion between an epoxy resin and a copper alloy is mainly included in the epoxy resin. The additional element improves the adhesion between the base material and the oxide film because of the hydrogen bond between the hydroxyl group formed and the oxygen atom of the oxide formed on the copper alloy. However, it has been found that in a liquid crystal polymer having a molecular formula as shown in FIG. 1, the effect of improving the adhesiveness with the resin cannot be obtained because the catalytic action of the additional element is obstructed when the oxide layer of the material surface layer becomes thick. In addition, in order to prevent the oxidation of the surface of foil products from progressing, a rust-preventive film is usually formed on the surface layer by applying benzotriazole or the like, but if this thickness is thick, it will prevent the rust-preventing film from being heated and stuck to the resin. Since the rust film is decomposed and the film itself is more easily peeled off from the base material, the adhesiveness with the resin is consequently reduced. As a result of research, the present inventors have found that in order to prevent such a decrease in adhesion with a liquid crystal polymer, an oxide layer formed on the surface layer of the material is 10 nm or less from the surface and an anticorrosive film is 5 nm or less from the surface. It was found that further improvement can be achieved by

The copper alloy foil of the present invention is not limited to a manufacturing method, and can be manufactured by a method such as an electrolytic copper foil by an alloy plating method or a rolled copper foil in which an alloy is melt cast and rolled. The manufacturing method by melt casting will be described below. Add a predetermined amount of alloying elements to the pure copper melt,
Cast into a mold to make 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.

In order to reduce the thickness of the oxide layer, it is necessary to remove the oxide layer produced by 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. Further, 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 thereof should be 5000 ppm or less. preferable.

[0017]

EXAMPLES Examples of the present invention will be described below. The copper alloy was prepared by melting oxygen-free copper, which is the main raw material, in a high-purity graphite crucible in an Ar atmosphere using a high-frequency vacuum induction melting furnace, and using silver, indium, aluminum, copper beryllium After adding an additive element selected from an alloy, cobalt, a copper iron master alloy, magnesium, manganese, nickel, a copper phosphorous master alloy, lead, a copper silicon master alloy, titanium and zinc, it was cast in a cast iron mold. By this method, a copper alloy ingot having a thickness of 30 mm, a width of 50 mm, a length of 150 mm and a weight of about 2 kg was obtained. This ingot was heated to 900 ° C. and rolled by hot rolling to a thickness of 8 mm to remove oxide scale, and then cold rolling and heat treatment were repeated to obtain a rolled copper alloy foil having 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 mass of sulfuric acid and 1% by mass of hydrogen peroxide to remove the oxide layer and the rust preventive film on the surface. This copper alloy foil was overlaid with a liquid crystal polymer without being subjected to a roughening treatment, and heat-bonded by using a plane heating press maintained at a temperature of 345 ° C. The liquid crystal polymer used here has the molecular formula shown in FIG.

The “tensile strength” of the copper alloy foil thus obtained
"Strength", "Conductivity", "Heat resistance", "Oxidation layer and anticorrosion film"
"Thickness" and "adhesion strength" with liquid crystal polymer
It evaluated by the method. (1) Tensile strength: Tensile strength is measured by a tensile test at room temperature.
Tensile strength was measured. The measurement sample is processed to a thickness of 35 μm
Width 12.7m using a precision cutter
m and 150 mm in length were cut into strips. Score this
The distance was 50 mm and the tensile speed was 50 mm / min. (2) Conductivity: Conductivity is the electrical resistance at 20 ℃
It was obtained by the DC four-terminal method using a Le bridge. The measurement sample is
Cut copper foil processed to a thickness of 35 μm into a width of 12.7 mm
I refused. Measure the electrical resistance of 50mm length during measurement
Then, the conductivity was obtained. (3) Heat resistance: Heat resistance is the room when heated for 1 hour
Tensile strength was measured at temperature, and the tensile strength before heating and softening
The heating temperature that is in the middle of the tensile strength of
And evaluated. (4) Thickness of oxide layer and rust preventive film: Auger electron spectroscopy
The depth of the oxide is analyzed and the "oxidation layer thickness" is
Is the surface until the detected intensity becomes the same as the background?
The depth of the rust preventive film is the thickness of the rust preventive agent.
The detected intensity of elementary nitrogen is the same as the background.
The depth from the surface until _TwoMeasured by conversion
did. (5) Adhesive strength: Adhesive strength is 180 ° peel strength JI
Performed in accordance with the method described in S C 5016.
It was The measurement was performed with the peeling conductor width set to 5.0 mm and the liquid crystal
The polymer is fixed on the tensile tester side, and the conductor is a copper alloy.
The foil was bent 180 ° and peeled off.

An embodiment relating to claims 1 and 3 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. No. of the embodiment. 1-No. 9 is an example of the copper alloy foil according to claim 1 and claim 3 of the present invention. As shown in Table 2, the copper alloy foil of the present invention has an electrical conductivity of 80% IACS or more, a 180 ° peel strength of 5.0 N / cm or more when a liquid crystal polymer is heat-sealed, and high conductivity. It can be seen that it has a high adhesive strength.

[0021]

[Table 1]

[0022]

[Table 2]

Next, examples of claims 2 and 3 of the present invention will be described. Table 3 shows the composition of the copper alloy foil and Table 4
Is the characteristic evaluation result. No. of the embodiment. 10-N
o. 14 is an example of the copper alloy foil according to claims 2 and 3 of the present invention. As shown in Table 4, the copper alloy foil of the present invention has an electric conductivity of 60% IACS or more, a tensile strength of 500 N / mm ² or more, and a 180 ° peel strength of 5 when the liquid crystal polymer is heat-sealed. It is 0 N / cm or more, and it can be seen that it has high strength and high adhesive strength.

[0024]

[Table 3]

[0025]

[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 and claim 3 of the present invention.
No. of the comparative example. 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 heat-bonded to a liquid crystal polymer. Since the material is pure copper, it has high conductivity,
Since the 180 ° peel strength is as small as 4.0 N / cm, the handling property is poor and peeling may occur when the printed wiring board is formed, which is not suitable for practical use.

[0027]

[Table 5]

[0028]

[Table 6]

No. of the comparative example. 16 and No. 17 is
Ag was added and processed into a foil 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 has a high heat resistance and a 180 ° peel strength, but has an electric conductivity of 80% I because the Ag concentration is more than 1.0% by mass.
It is less than ACS, which is low and is not suitable as a conductive material for a printed wiring board that requires high conductivity. No. of the comparative example. 18 and No. No. 19 was processed into a foil by adding In in the same manner as in the example. No. Since No. 18 has a low In concentration, it has high 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, N
o. No. 19 has a high heat resistance and a 180 ° peel strength because the In concentration is more than 1.0% by mass, but the electrical conductivity is low at less than 80% IACS, and the printed wiring that requires high electrical conductivity. Not suitable as a conductive material for plates.

No. 20 and No. 20. Reference numeral 21 is a comparative example relating to claims 2 and 3 of the present invention. No. of the comparative example. No. 20 contains P and Ni in addition to Ag, and No. 20. Two
In No. 1, Ti was added in addition to In to form a foil in the same manner as in the example. However, when P or Ti was added, the tensile strength increased and the heat resistance and adhesiveness were improved, but the addition amount of P or Ti was 2.5 mass% by weight.
If added in excess of 1, the conductivity will be lower than 60% IACS, which is not suitable as a conductive material for a printed wiring board.

No. of the comparative example. No. 23 of the example. The alloy foil of No. 2 was used to adjust the concentration of benzotriazole to 7,000.
It was immersed in an aqueous solution adjusted to ppm. When the peel strength of this was evaluated, the rust-preventive film was 7
The 180 ° peel strength is 1.4N due to the increase in thickness of nm
It was as small as / cm. No. of the comparative example. No. 24 of the example. The thickness of the oxide layer was adjusted to 12 nm by heat-treating the alloy foil of No. 2 in the atmosphere. When the peel strength was evaluated for this, the 180 ° peel strength was as small as 4.1 N / cm.

[0032]

EFFECT OF THE INVENTION A copper alloy foil used for a laminate of a printed wiring board having a liquid crystal polymer as a base material of the present invention has high conductivity and tensile strength, and is used as a base resin by a roughening treatment. It has excellent adhesiveness. This makes it easy to handle and is suitable for use as a conductive material for electronic circuits with fine wiring.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a molecular formula of a liquid crystal polymer used in Examples and Comparative Examples.

FIG. 2 is an explanatory diagram of a bisphenol A type epoxy resin which is an example of an epoxy resin.

Claims (3)

[Claims] 1. Ag is 0.03% by mass to 1.0% by mass and In is 0.01% by mass, in terms of a weight ratio of the additive element components.
~ 0.5% by mass of each component, the balance consisting of copper and unavoidable impurities, the thickness of the oxide layer of the outermost surface layer is 10 nm or less from the surface, and the thickness of the rust preventive film is 5 nm from the surface.
By having the following, the electrical conductivity is 80% IACS or more, and the 180 ° peel strength is 5.0 N / cm or more when the liquid crystal polymer is heat-sealed without roughening treatment. , Copper alloy foil for laminated boards. 2. Ag is 0.03% by mass to 1.0% by mass and In is 0.01% by mass, in terms of a weight ratio of the additive element components.
~ 0.5% by mass of each component, and further A
l, Be, Co, Fe, Mg, Mn, Ni, P, Pb,
The total amount of one or more of Si, Ti, and Zn components is 0.005 to 2.5% by mass, and the balance is copper and unavoidable impurities. By setting the thickness of the anticorrosion film to 10 nm or less and the thickness of the rust preventive film to 5 nm or less from the surface, the tensile strength is 500 N / mm ² or more, the conductivity is 60% IACS or more, and the liquid crystal polymer is heated without roughening treatment. A copper alloy foil for a laminate, which has a 180 ° peel strength of 5.0 N / cm or more when fused. 3. The temperature at which the tensile strength when heated for 1 hour is intermediate between the tensile strength before heating and the tensile strength when softened is 300 ° C. or higher. The copper alloy foil for laminated plates according to 1 or 2.