KR20230006808A - Metal laminated film and manufacturing method thereof - Google Patents

Abstract

A main object is to provide a metal laminated film capable of improving the transmission characteristics of a printed wiring board. A metal layer is laminated on at least one surface of the liquid crystal polymer film, and an orientation degree (F) of the central portion in the thickness direction of the liquid crystal polymer film is 0.31 or more.

Description

Metal laminated film and manufacturing method thereof

The present invention relates to a metal laminated film and a manufacturing method thereof.

BACKGROUND ART [0002] Conventionally, a metal laminated film in which a metal layer such as copper foil is laminated on a rigid substrate such as a paper base material phenol resin or a polymer film such as a liquid crystal polymer film is known as a base material for producing a printed wiring board. Recently, in preparation for the advent of the 5th generation mobile communication system (5G), development of a metal laminated film in which a metal layer such as copper foil is laminated on a liquid crystal polymer film having low dielectric properties is progressing to improve the high frequency characteristics of a printed wiring board. It is becoming.

As a metal laminated film, generally, what is produced using the hot lamination method of heat-pressing the metal foil which roughened the compression surface from the adhesive viewpoint with respect to a polymer film is known. For example, in Patent Document 1, a high-frequency circuit board having a molecular orientation degree (SOR) of a liquid crystal polymer film of 1.3 or less is provided, which is produced by heat-pressing a rolled copper foil to a liquid crystal polymer film using a thermal lamination method. This is disclosed. Further, in Patent Document 2, while continuously supplying a liquid crystal polymer film and a copper foil having a specified surface roughness (Rz) on the crimping surface, the liquid crystal polymer film is heated to a temperature equal to or higher than the melting point using a thermal lamination method to form a copper foil against the liquid crystal polymer film. Disclosed is a laminated board for a flexible printed wiring board produced by heat-pressing.

On the other hand, as a metal laminated film, surface activation bonding is used in which the surface of a laminate is activated by removing oxides, contamination, etc. by a method such as sputter etching, and the surface of the activated laminate is brought into contact with the surface of another laminate to be bonded by rolling. It is also known that it is made by. For example, in Patent Document 3, a metal thin film surface activated by sputter etching in a metal thin film laminate film in which a metal thin film is formed on the surface of a polymer film as a metal laminate film for a flexible circuit board or the like is press-contacted with the metal foil surface A multi-layer metal laminated film produced by doing is disclosed.

Patent Document 1: Japanese Unexamined Patent Publication No. 2000-269616 Patent Document 2: Japanese Patent No. 5411656 Patent Document 3: Japanese Patent No. 4532713

In the case of fabricating a metal laminated film by heating and compressing a metal layer to a liquid crystal polymer film using the thermal lamination method disclosed in Patent Documents 1 and 2, it is necessary to heat the liquid crystal polymer film to a melting point or higher. For this reason, as a result of heating the liquid crystal polymer film to around or above the melting point, there are cases where the film is greatly altered and its orientation is greatly disturbed. This may lead to deterioration of the dielectric properties of the liquid crystal polymer film, thereby deteriorating the transmission characteristics of a printed wiring board made of the metal laminated film.

On the other hand, in the multilayer metal laminate film disclosed in Patent Document 3, which is a metal laminate film produced by surface activation bonding, a liquid crystal polymer film is not used for the polymer film. Therefore, the printed wiring board produced therefrom had low transmission characteristics especially in a high-frequency region (for example, 28 GHz).

Therefore, the main object of the present invention is to provide a metal laminated film capable of improving the transmission characteristics of a printed wiring board and a manufacturing method thereof.

As a result of intensive studies by the inventors of the present invention, when a liquid crystal polymer film is used for a polymer film of a metal laminate film, by bonding a metal layer to the liquid crystal polymer film by surface activation bonding to produce a metal laminate film, the liquid crystal polymer film Disorder of orientation can be suppressed, and it discovered that the said subject could be solved, and this invention was completed. That is, the gist of the present invention is as follows.

(1) A metal laminated film characterized in that a metal layer is laminated on at least one surface of a liquid crystal polymer film, and the orientation degree (F) of the central portion in the thickness direction of the liquid crystal polymer film is 0.31 or more.

(2) A metal layer is laminated on at least one surface of the liquid crystal polymer film, and the orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film is the central portion in the thickness direction of the liquid crystal polymer film before the metal layer is laminated. Metal laminated film, characterized in that 77% or more of the degree of orientation (F) of.

(3) The metal laminated film according to (1) or (2) above, wherein the average degree of orientation (F) in the thickness direction in the liquid crystal polymer film is 0.31 or more.

(4) Any one of (1) to (3) above, wherein the dielectric loss tangent of the liquid crystal polymer film is less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated. The metal laminated film described.

(5) The metal laminated film according to any one of (1) to (4), wherein the bonding strength between the metal layer and the liquid crystal polymer film is 2.0 N/cm or more.

(6) The metal laminated film according to any one of (1) to (5), wherein the metal layer has a metal foil.

(7) The metal laminated film according to (6) above, wherein the metal layer further includes an intermediate layer containing a metal between the liquid crystal polymer film and the metal foil.

(8) The intermediate layer contains any one type of metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver, and gold, or an alloy containing the metal. The metal laminated film according to (7) above, characterized by the above-mentioned.

(9) The metal laminate film according to any one of (6) to (8), wherein the metal foil is copper foil, copper alloy foil, or copper foil with a carrier.

(10) A method for producing a metal laminated film according to (7) above, wherein a step of preparing a liquid crystal polymer film and a metal foil (preparation step), and a step of laminating an intermediate layer containing a metal on at least one surface of the liquid crystal polymer film ( interlayer lamination process), a process of activating the surface of the intermediate layer by sputter etching (activation process), a process of activating the surface of the metal foil by sputter etching (activation process), and the activation of the intermediate layer and the metal foil. A process of rolling bonding the surfaces together at a reduction ratio of 0 to 30% (roll bonding process), the intermediate layer and the metal layer having the metal foil and the liquid crystal polymer film that are roll joined, the liquid crystal polymer A method for producing a metal laminated film comprising a step of performing heat treatment at a temperature of the melting point of the film -100 ° C. or higher and the melting point - 10 ° C. or lower (heat treatment step).

(11) The method for producing a metal laminated film according to (10) above, wherein the degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film after the heat treatment is 0.31 or more.

(12) Characterized in that the degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film after the heat treatment is 77% or more of the degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film before the metal layer is laminated. The method for producing a metal laminated film according to (10) or (11) above.

(13) The dielectric loss tangent of the liquid crystal polymer film after the heat treatment is less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated according to any one of (10) to (12) above. A method for producing a metal laminated film.

This specification includes the disclosure of Japanese Patent Application No. 2020-075910, which is the basis for the priority of this application.

ADVANTAGE OF THE INVENTION According to this invention, the transmission characteristic of a printed wiring board can be improved.

[Fig. 1] A schematic cross-sectional view showing an example of a metal laminated film of an embodiment.
[ Fig. 2A ] A schematic cross-sectional view showing a main part of an example of a method for manufacturing a metal laminated film of an embodiment.
[ Fig. 2B ] A schematic cross-sectional view showing a main part of an example of a method for manufacturing a metal laminated film of an embodiment.
[Fig. 3] It is a schematic diagram showing a measurement region of orientation degree (F) in a slice of a liquid crystal polymer film.
[Fig. 4] is a graph showing the degree of orientation (F) for each position of a measurement area in slices of untreated and liquid crystal polymer films of Example 1 and Comparative Example 2.

Hereinafter, embodiments relating to the metal-laminated film of the present invention and its manufacturing method will be described.

A. Metal Laminated Film

Here, an embodiment of the metal-laminated film of the present invention will be exemplified and described. 1 is a schematic cross-sectional view showing an example of a metal laminated film of an embodiment.

As shown in FIG. 1 , in the metal laminated film 1A of this example, the metal layer 10 is laminated on one surface 20a of the liquid crystal polymer film 20 . The metal layer 10 includes an intermediate layer 14 containing copper laminated on one surface 20a of the liquid crystal polymer film 20 and a surface 14a of the intermediate layer 14 opposite to the liquid crystal polymer film 20 side. It has laminated copper foil (metal foil) 12.

The orientation degree (F) of the center portion in the thickness direction of the liquid crystal polymer film 20 before the metal layer 10 is laminated is 0.4. On the other hand, in the metal laminated film 1A, the orientation degree (F) of the center portion in the thickness direction in the liquid crystal polymer film 20 is 0.31 or more, and in the liquid crystal polymer film 20 before the metal layer 10 is laminated. It is 77% or more of the orientation degree (F) of the central part in the thickness direction of . As a result, the dielectric loss tangent of the liquid crystal polymer film 20 is less than 114% of the dielectric loss tangent of the liquid crystal polymer film 20 before the metal layer 10 is laminated. For this reason, the transmission characteristics of the printed wiring board produced with the metal laminated film 1A can be improved. Also, since the bonding strength between the metal layer 10 and the liquid crystal polymer film 20 is 2.0 N/cm or more, the adhesion between the metal layer 10 and the liquid crystal polymer film 20 is high. For this reason, the reliability of the fine wiring of the printed wiring board produced with the metal laminated film 1A can also be improved.

Therefore, according to the metal-laminated film of the embodiment, the transmission characteristics of the printed wiring board can be improved as in the case of the metal-laminated film 1A of the above example. Further, when the bonding strength between the metal layer and the liquid crystal polymer film is 2.0 N/cm or more, it is possible to achieve both the transmission characteristics of the printed wiring board and the reliability of fine wiring.

Subsequently, each configuration of the metal laminated film of the embodiment will be described in detail.

1. Liquid crystal polymer film

The degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film is 77% or more of the degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film before the metal layer is laminated.

Here, "liquid crystal polymer film" refers to a film made of an aromatic polyester-based resin having parahydroxybenzoic acid or the like as a basic structure that exhibits liquid crystal properties in a dissolved state.

Here, "degree of orientation (F)" means the degree of molecular orientation in MD (stretching direction of the film), and is calculated using the following method. First, by attaching a polarizer for infrared light to a micro-infrared spectrometer (micro-FT-IR device), the infrared transmission spectrum of the polarization direction parallel to the MD of the polymer film (here, the liquid crystal polymer film) and the polarization direction perpendicular to the MD Measure the infrared transmission spectrum. Next, by using the peak at 1601 cm ^-1 of these infrared transmission spectra, the infrared dichroic ratio (D ) (the peak intensity at 1601 cm ^-1 of the infrared transmission spectrum in the polarization direction parallel to MD (A ) and the peak intensity (A⊥) at 1601 cm ⁻¹ of the infrared transmission spectrum in the direction of polarization perpendicular to the MD) is obtained. In addition, the baseline of these peak intensities is set as a straight line connecting 1618.9 cm ^-1 and 1572.4 cm ^-1 of each infrared transmission spectrum. In addition, the peak at 1601 cm ^-1 is attributed to the C=C stretching vibration of the benzene ring and has a transition moment parallel to the molecular chain. Next, the degree of orientation (F) is calculated from the infrared dichroic ratio (D). In addition, the calculation methods of the infrared dichroic ratio (D) and the degree of orientation (F) are Equations (1) and (2), respectively.

[Equation 1]

[Equation 2]

"Orientation degree (F) of the central part in the thickness direction" means, for example, the infrared dichroic ratio (D ), and refers to the degree of orientation (F) calculated from the infrared dichroic ratio (D) measured in the measurement area. In addition, although this measurement area|region is not specifically limited, For example, the rectangular area|region of 100 micrometers x 10 micrometers in length of MD shown in FIG. 3, etc. are mentioned.

The "liquid crystal polymer film before the metal layer is laminated" refers to the liquid crystal polymer film prepared in the preparatory step described in the section of "B. Manufacturing method of metal laminated film 1. Preparatory step" to be described later.

The degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film is not particularly limited as long as it is 77% or more of the degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film before the metal layer is laminated. The closer the degree of orientation (F) of the center portion in the thickness direction in the liquid crystal polymer film is, the more preferable it is, but specifically, for example, it is 0.31 or more, more preferably 0.315 or more, still more preferably 0.32 or more. This is because the transmission characteristics are improved in particular.

The average of the degree of orientation (F) in the thickness direction in the liquid crystal polymer film is not particularly limited, and it is preferable that it is closer to the average degree of orientation (F) in the thickness direction in the liquid crystal polymer film before the metal layer is laminated. It is preferably 79% or more of the average degree of orientation (F) in the thickness direction in the liquid crystal polymer film. This is because the transmission characteristics are improved. Further, the average of the degree of orientation (F) in the thickness direction in the liquid crystal polymer film is, for example, preferably 0.31 or more, and more preferably 0.315 or more. This is because the transmission characteristics are improved in particular.

Here, the term "average of the degree of orientation (F) in the thickness direction" means, for example, equally dividing a length region of a predetermined MD in a cross section perpendicular to the surface of the liquid crystal polymer film and parallel to the MD (vertical cross section) in the thickness direction. It refers to the average value of a plurality of degrees of orientation (F) calculated from infrared dichroic ratios (D) measured in a plurality of measurement regions (for example, five or more measurement regions). In addition, although it is not specifically limited as a plurality of measurement areas, for example, five rectangular areas shown in FIG. 3 are located at distances in the thickness direction from the surface of 5 μm, 15 μm, 25 μm, 35 μm, and 45 μm, respectively. can

The dielectric loss tangent of the liquid crystal polymer film is not particularly limited, and is preferably closer to the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated. For example, less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated. Preferably, less than 112% of the dielectric loss tangent of the liquid crystal polymer film before the lamination of the metal layer is preferred, and more preferably less than 110%. This is because the transmission characteristics are improved. The dielectric loss tangent of the liquid crystal polymer film is preferably less than 0.0024, for example. This is because the transmission characteristics are improved in particular.

Here, "dielectric loss tangent" refers to the dielectric loss tangent around 28 GHz, for example, by using an open resonance method, the measurement frequency is 28 GHz, and the relative permittivity / dielectric loss tangent measurement system (DPS03 manufactured by Kicom Co., Ltd.) is used to measure. .

The thickness of the liquid crystal polymer film can be appropriately set according to the purpose of the metal laminated film. For example, when used as a flexible printed circuit board, the thickness is preferably 10 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less. In addition, the thickness of the liquid crystal polymer film can be measured with a micrometer or the like, and refers to an average of thicknesses measured at 10 randomly selected points on the surface of the target liquid crystal polymer film. Further, for the liquid crystal polymer film, the deviation from the average of 10 measured values is preferably within 20%, more preferably within 15% for all measured values.

2. Metal layer

The metal layer is not particularly limited as long as it has a metal foil, and like the metal layer 10 in the metal laminated film 1A shown in FIG. 1, an intermediate layer containing a metal is further formed between the liquid crystal polymer film and the metal foil in addition to the metal foil It may have or may be the metal foil, but it is preferable to further have an intermediate layer containing a metal between the liquid crystal polymer film and the metal foil in addition to the metal foil. Hereinafter, the metal foil included in the metal layer and the intermediate layer when the metal layer includes the intermediate layer and the metal foil will be described.

(1) metal foil

The metal foil varies depending on the use of the metal laminated film and is not particularly limited. can be heard As metal foil, copper foil, copper alloy foil, etc. are preferable especially. This is because, for example, a flexible substrate for forming fine wiring can be obtained by rolling bonding these with a liquid crystal polymer film. Further, when producing a flexible substrate for forming finer wiring, it is preferable to use a copper foil with a carrier composed of an ultra-thin copper foil, a release layer, and a carrier layer as the metal foil. When copper foil with a carrier is used, the copper foil with a carrier is laminated in the order of an ultra-thin copper foil, a release layer, and a carrier layer from the liquid crystal polymer film side or the middle layer side. Although it does not specifically limit as copper foil with a carrier layer, MT18FL by Mitsui Metal Mining Co., Ltd., JXUT-III by JX Metal Co., Ltd., etc. are mentioned.

The thickness of the metal foil is not particularly limited depending on the use of the metal laminated film, but is preferably 3 μm or more and 100 μm or less, and among them, 10 μm or more and 35 μm or less are preferable for flexible printed wiring boards, for example. When using copper foil with a carrier layer as the metal foil, the thickness of the ultra-thin copper foil is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less, for example. In addition, the thickness of the release layer is not particularly limited, but is preferably, for example, 1 nm or more and 1 μm or less, and the thickness of the carrier layer is not particularly limited, but is preferably, for example, 10 μm or more and 100 μm or less.

In addition, although not described in FIG. 1 as a metal layer, at least one type of layer, such as a roughened particle layer, a rust prevention layer (rust prevention layer), and a layer treated with a silane coupling agent, on the surface of the liquid crystal polymer film side of the metal foil (Hereafter also referred to as "processing layer") may be further included. As for the treatment layer, any one type of layer may be laminated, or a plurality of types of layers may be laminated. The roughened particle layer may include, for example, any one type of metal selected from the group consisting of Cu, Co, and Ni, or an alloy thereof, but is not limited thereto. Specifically, a cobalt-nickel alloy plating layer, a copper-cobalt-nickel alloy plating layer, etc. are mentioned. In addition, the anti-rust layer may include, for example, any one type of metal selected from the group consisting of Cr, Ni, and Zn, or an alloy thereof, but is not limited thereto. Specifically, chromium oxide film treatment, mixture film treatment of chromium oxide and zinc/zinc oxide, Ni plating layer, and the like are exemplified. Examples of the silane coupling agent include olefin-based silane, epoxy-based silane, acrylic-based silane, amino-based silane, and mercapto-based silane, but are not limited thereto. The application of the silane coupling agent can be carried out using appropriate methods such as spraying by spraying, coating by a coater, and immersion.

(2) middle layer

The intermediate layer is not particularly limited as long as it is a layer containing metal, and may be a layer containing a single layer of metal, or a layer containing two or more layers of metal may be laminated. As the intermediate layer, a layer formed by sputtering or vapor deposition or electroless plating provided on a liquid crystal polymer film may be used.

The intermediate layer is not particularly limited as long as it contains a metal, but is any one selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver, gold, aluminum, palladium, and zirconium. It is preferable to include a metal of or an alloy containing the metal. Further, the intermediate layer may be a laminate of a plurality of metal-containing layers. In particular, when the metal foil is a copper foil or a copper alloy foil, it is preferable that the middle layer also contains a copper alloy such as copper or a copper-nickel alloy, and among these, a metal having the same composition as the metal foil is preferably included. This is because etching becomes easy.

When the intermediate layer is, for example, a Cu-Ni alloy, the ratio of Ni to Cu is preferably 10 to 90% in terms of at%. However, it is not limited thereto. By providing the intermediate layer, it is possible to protect the surface of the metal foil or the liquid crystal polymer film and to improve the adhesion between the metal foil and the liquid crystal polymer film, as well as impart functions specific to the intermediate layer (e.g., etching during etching processing). function as a stopper layer, etc.). The thickness of the intermediate layer may be any thickness capable of exhibiting functions such as improving adhesion, and is not particularly limited.

3. Metal laminated film

The metal laminated film is not particularly limited, but as in the metal laminated film 1A shown in Fig. 1, it is preferable that the bonding strength between the metal layer and the liquid crystal polymer film is 2.0 N/cm or more. It is because the reliability of fine wiring of a printed wiring board can be improved.

In addition, in order to measure the value of the said bonding strength, first, a test piece is made from the metal laminated film, and the metal layer is cut with a width of 1 cm using a knife or the like. Then, after partially peeling the metal layer and the liquid crystal polymer film, the liquid crystal polymer film is fixed to the support and the metal layer is stretched in a direction of 90° with respect to the liquid crystal polymer film at a rate of 50 mm/min. The force required for pulling at that time is referred to as the bonding strength (unit: N/cm). In addition, when the metal layer is thin and brittle, there is a risk of cutting when measuring the bonding strength. In that case, the surface of the metal layer may be subjected to electrolytic plating (eg, copper plating when the metal layer is copper) to increase the thickness of the metal layer to about 5 to 50 μm, and then the bonding strength may be measured. The measuring method of the value of the said joint strength is the measuring method prescribed|regulated by JIS C6471.

In this specification, when the term "bonding strength between the metal layer and the liquid crystal polymer film" means the bonding strength when the metal layer and the liquid crystal polymer film are separated from each other at the interface, the bonding strength when the inside of the metal layer is destroyed and the liquid crystal polymer film is separated, and bonding strength when the inside of the liquid crystal polymer film is broken and peeled off.

The metal laminate film can be used as a metal layer laminate for producing a flexible printed circuit board.

A printed wiring board on which fine wiring is formed can be obtained using the metal laminated film. In the process of forming the wiring, an additional metal layer may be formed only in the wiring portion. Specifically, a printed wiring board can be obtained by appropriately using known methods such as a modified semi-additive method (MSAP method), a semi-additive method (SAP method), or a subtractive method. For example, in the case of using the modified semi-additive method (MSAP method), the non-wiring portion on the metal layer in the metal laminate film is masked, copper plating is performed on the unmasked portion to form an additional metal layer, and the masking is removed, A printed wiring board can be manufactured by removing the metal layer covered by masking by etching. In addition, the "printed wiring board" in the present invention includes not only a laminate in which wiring is formed, but also a board in which electronic components such as ICs are mounted after wiring is formed.

In the metal laminated film 1A shown in FIG. 1, the case where a metal layer is laminated on one surface of the liquid crystal polymer film has been described, but the metal laminated film is not limited thereto. That is, if necessary, metal layers may be provided on both surfaces of the liquid crystal polymer film. By using a metal laminated film in which metal layers are provided on both surfaces of the liquid crystal polymer film, a flexible printed circuit board having wires formed on both surfaces of the liquid crystal polymer film can be obtained.

B. Manufacturing method of metal laminated film

Here, an embodiment relating to the method for manufacturing a metal-laminated film of the present invention will be exemplified and described. 2A and 2B are schematic cross-sectional views showing main parts of an example of a method for manufacturing a metal laminated film according to an embodiment.

In the manufacturing method of the metal laminated film of this example, first, a liquid crystal polymer film and copper foil (metal foil) are prepared. The degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film is 0.4.

Next, as shown in (a) of FIG. 2A, one surface 20a of the liquid crystal polymer film 20 is activated by sputter etching at room temperature using an activation device (not shown). Subsequently, as shown in (b) of FIG. 2A, an intermediate layer 14 including copper is sputtered on the surface 20a of the liquid crystal polymer film 20 activated at room temperature using a sputter device (not shown). .

Next, as shown in (c) of FIG. 2A, the surface 14a of the intermediate layer 14 is activated by sputter etching at room temperature using an activation bonding device (not shown), and the surface of the copper foil 12 (12a) is activated by sputter etching, and the activated surfaces of the intermediate layer 14 and the copper foil 12 are roll-bonded at a reduction ratio of 0 to 30%.

Next, as shown in (d) of FIG. 2B, a heat treatment furnace (not shown) is applied to the metal layer 10 and the liquid crystal polymer film 20 having the intermediate layer 14 and the copper foil 12 that are roll-joined. melting point of the liquid crystal polymer film 20 -100°C or higher in a vacuum atmosphere or in an inert gas atmosphere such as N ₂ , Ar, NH gas (for example, N ₂ +5% H ₂ mixed gas) by using liquid crystal polymer Heat treatment is performed at a temperature below the melting point of the film 20 -10°C. This improves the adhesion between the metal layer 10 and the liquid crystal polymer film 20 . By the above, as shown in (e) of FIG. 2B, the metal laminated film 1A is manufactured.

In the manufacturing method of the metal laminated film of this example, the process of activating the surface 20a of the liquid crystal polymer film 20 by sputter etching, the process of sputtering the middle layer 14, the process of forming the middle layer 14 and the copper foil 12 The treatment of activating the surface by sputter etching and the treatment of roll bonding the activated surfaces of the intermediate layer 14 and the copper foil 12 are performed at room temperature. Thereafter, the melting point of the liquid crystal polymer film 20 is -100°C or more and heat treatment is performed at a temperature of the melting point of the liquid crystal polymer film 20 -10°C or less to improve adhesion between the metal layer 10 and the liquid crystal polymer film 20 . For this reason, unlike the case of producing a metal laminated film using the thermal lamination method, since the liquid crystal polymer film 20 is not heated to a temperature near or exceeding the melting point, the metal layer 10 and the liquid crystal Not only can the adhesion of the polymer film 20 be improved, but also the orientation of the liquid crystal polymer film 20 may be disturbed and deterioration of its dielectric properties can be suppressed, thereby suppressing the deterioration of the surface shape of the liquid crystal polymer film 20. can

Therefore, according to the manufacturing method of the metal-laminated film of the embodiment, as in the manufacturing method of the above example, the adhesion between the metal layer and the liquid crystal polymer film is improved, and the metal-laminated film in which deterioration of dielectric properties is suppressed can be manufactured. Therefore, it is possible to manufacture a metal laminated film capable of achieving both the transmission characteristics of a printed wiring board and the reliability of fine wiring.

Subsequently, each condition of the manufacturing method of the metal laminated film of the embodiment will be described in detail.

1. Preparation process

The liquid crystal polymer film prepared in the preparation step is not particularly limited, but preferably has an orientation degree (F) of 0.4 or more at the central portion in the thickness direction, and among these, Baxter CTQ manufactured by Kuraray Co., Ltd. is preferable. This is because the dielectric loss tangent is low and the dielectric properties are excellent.

About the metal foil prepared in the preparatory process, since it is the same as the metal foil demonstrated in the item of "A. Metal laminated film 2. Metal layer (1) metal foil", description here is abbreviate|omitted.

2. Interlayer lamination process

In the intermediate layer lamination step, a method of laminating an intermediate layer containing a metal on at least one surface of the liquid crystal polymer film is not particularly limited, but for example, after activating at least one surface of the liquid crystal polymer film by sputter etching, the activation A method of sputtering an intermediate layer containing a metal on the surface thereof is preferably formed. Conditions for performing sputter film formation by this method can be appropriately set depending on the type of metal constituting the intermediate layer and the thickness of the intermediate layer. Since the metal species constituting the intermediate layer and the thickness of the intermediate layer are the same as those of the intermediate layer described in the section "A. Metal Laminated Film 2. Metal Layer (2) Intermediate Layer", description thereof is omitted.

3. Activation Process

In the sputter etching treatment in the activation step, for example, a metal foil to be joined or a liquid crystal polymer film having an intermediate layer is prepared as a long coil having a width of 100 mm to 600 mm, and the bonding surface of the metal foil or intermediate layer is grounded as one electrode. , an alternating current of 1 MHz to 50 MHz is applied between the other insulated and supported electrodes to generate glow discharge, and the area of the electrode exposed to the plasma generated by the glow discharge is reduced to 1/3 or less of the area of the other electrode can do. During the sputter etching process, the grounded electrode takes the form of a cooling roll to prevent a rise in the temperature of the conveying material.

In the sputter etching treatment in the activation step, the surface to which the metal foil or the liquid crystal polymer film provided with the intermediate layer is bonded is sputtered with an inert gas under vacuum to completely remove adsorbed substances on the surface and also to remove part or all of the oxide layer on the surface. . The oxide layer of copper is preferably completely removed. As an inert gas, argon, neon, xenon, krypton, etc., and a mixed gas containing at least one of these can be applied. Depending on the type of metal, the adsorbed material on the surface of the metal foil and the intermediate layer can be completely removed with an etching amount of about 1 nm, and in particular, the copper oxide layer can usually be removed at about 5 nm to 12 nm (in terms of SiO ₂ ).

The processing conditions of sputter etching can be appropriately set depending on the type of metal foil and intermediate layer. For example, it can be implemented with a plasma output of 100 W to 10 kW and a line speed of 0.5 m/min to 30 m/min under vacuum. The degree of vacuum at this time is preferably high in order to prevent re-adsorbed substances to the surface, but may be, for example, 1×10 ^-5 Pa to 10 Pa.

In addition, when a roughened particle layer or an antirust layer is provided on the surface of the metal foil, the surface of the roughened particle layer or the antirust layer is activated by sputter etching. At that time, the roughened particle layer and the rust-preventive layer may be completely removed by sputter etching, or may remain without being removed.

In addition, Ni plating, chromate treatment, silane coupling agent treatment, etc. may be applied to the surface of the metal foil or the surface of the intermediate layer before activation by sputter etching, if necessary, to prevent oxidation or improve adhesion. In addition, the surface of the metal foil can be roughened as needed in order to improve adhesion with the intermediate layer.

4. Roll joining process

The pressure welding between the metal foil subjected to sputter etching and the surfaces in which the intermediate layer is activated can be performed by roll pressure welding. The rolling wire load of roll welding is not particularly limited, and can be carried out by setting it in the range of, for example, 0.1 tf/cm to 10 tf/cm. However, when the thickness of the metal foil or the liquid crystal polymer film provided with the intermediate layer is large before bonding, it may be necessary to increase the load of the rolling line in order to secure the pressure during bonding, and the numerical range is not limited thereto. On the other hand, if the rolling line load is too high, since not only the surface layer of the metal foil or the intermediate layer but also the joint interface is easily deformed, there is a fear that the thickness accuracy of each layer in the metal laminated film is lowered. In addition, when the rolling line load is high, there is a possibility that processing strain applied at the time of bonding will increase.

The reduction ratio at the time of rolling joining is set to 0 to 30%. Preferably it is 0 to 15%. Since the method using the surface activation bonding can lower the reduction ratio, it is possible to form a metal layer having excellent thickness accuracy without causing wrinkles or cracks. In addition, since the curvature of the interface between the metal foil and the intermediate layer and the liquid crystal polymer film can be reduced, when pattern etching is performed on the metal layer having the metal foil and the intermediate layer to form wiring, the thickness accuracy is excellent, so precise wiring can be obtained.

Joining by roll welding is carried out in a non-oxidizing atmosphere, for example, in a vacuum atmosphere or in an inert gas atmosphere such as Ar, in order to prevent deterioration in the bonding strength between the two due to re-adsorption of oxygen to the surface of the metal foil or intermediate layer. it is desirable

5. Heat treatment process

The heat treatment temperature is preferably equal to or higher than the melting point of the liquid crystal polymer film -100°C or higher and lower than or equal to -10°C the melting point of the liquid crystal polymer film, and above all, equal to or higher than the melting point of the liquid crystal polymer film -70°C or higher and lower than -20°C the melting point of the liquid crystal polymer film. By setting the heat treatment temperature at or above the lower limit of this range, the bonding strength between the metal layer and the liquid crystal polymer film can be increased to a desired strength, and the shape of the metal laminated film curved during roll bonding can be flattened. By setting the heat treatment temperature below the upper limit of this range, the orientation of the liquid crystal polymer film can be prevented from being disturbed, and the thickness or width of the metal laminated film can be suppressed from being softened and changed. In addition, since the melting point of the liquid crystal polymer film varies depending on the material, the heat treatment temperature can be appropriately set according to the material. For the same reason, it is a temperature of 210°C or more and 300°C or less, and among them, a temperature of 240°C or more and 290°C or less is preferable.

Although the atmosphere for heat treatment is not particularly limited, a vacuum atmosphere or an inert gas atmosphere such as N ₂ , Ar, or NH gas is preferable, and a vacuum atmosphere is particularly preferable. This is because it is possible to prevent the metal layer from being oxidized by the heat treatment and thus reducing the bonding strength between the metal layer and the liquid crystal polymer film.

The time for the heat treatment is not particularly limited as long as the bonding strength between the metal layer and the liquid crystal polymer film can be set to a desired strength and the orientation of the liquid crystal polymer film can be prevented from being disturbed. seconds or less is preferable, and 200 seconds or more and 15000 seconds or less are preferable especially. This is because sufficient adhesion between the metal layer and the liquid crystal polymer film can be ensured by setting it at or above the lower limit of this range, and because it is possible to realize high production efficiency and low cost of the metal laminated film by setting it below the upper limit of this range.

The heat treatment method is, for example, a batch type heat treatment furnace in a desired atmosphere (for example, in a vacuum atmosphere or in an inert gas atmosphere such as N ₂ , Ar, or NH gas) to heat the metal layer and the liquid crystal polymer film in the desired condition. and a method of maintaining the heat treatment temperature for a desired period of time. Further, depending on the heat treatment temperature or atmosphere, heat treatment may be performed in a roll-to-roll manner using a continuous heat treatment furnace. In this case, at least the heating section or the cooling section in the continuous heat treatment furnace is set to a desired atmosphere (for example, a vacuum atmosphere or an inert gas atmosphere such as N ₂ , Ar, or NH gas) and maintained at a desired temperature, and then the metal layer and the liquid crystal polymer film are A method of maintaining the metal layer and the liquid crystal polymer film at a desired heat treatment temperature for a desired time by passing a heating unit or a cooling unit at a desired rate, and the like.

6. Manufacturing method of metal laminated film

In the manufacturing method of the metal laminated film of the embodiment, the degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film after heat treatment is 77 of the degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film before the metal layer is laminated. % or more is preferred. The degree of orientation (F) of the central portion in the thickness direction of the liquid crystal polymer film after heat treatment is preferably 0.31 or more. In addition, the dielectric loss tangent of the liquid crystal polymer film after heat treatment is preferably less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated, and among them, it is preferably less than 112% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated. and more preferably less than 110%.

Bonding and/or heat treatment under high pressure when producing a metal laminated film significantly changes the structure of each layer of the metal laminated film before and after bonding and/or before and after heat treatment, and may impair the characteristics of the metal laminated film. It is desirable to select bonding and heat treatment conditions that can prevent such structural changes.

Example

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)

First, a liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-50) with a thickness of 50 μm was prepared, and two rolled copper foils with a thickness of 16 μm were prepared as metal foil. Next, both surfaces of the liquid crystal polymer film were activated one by one by sputter etching, and then an intermediate layer (copper layer) containing copper (40 nm in thickness) was formed by sputtering on both surfaces of the activated liquid crystal polymer film. Next, the surface of one intermediate layer and the surface of one rolled copper foil are activated by sputter etching, and the activated surface of the rolled copper foil is brought into contact with the activated surface of the intermediate layer, and then a line load of 1.5 tf/cm is applied. The intermediate layer and the activated surfaces of the rolled copper foil were roll bonded to each other. In addition, the surface of the middle layer on the side where the rolled copper foil is not laminated is activated by sputter etching, and the surface of the other rolled copper foil is activated by sputter etching, and the activated surface of the rolled copper foil is activated with respect to the activated surface of the middle layer. After contacting, the activated surfaces of the intermediate layer and the rolled copper foil were roll-joined with a line load of 1.5 tf/cm. The reduction ratio was 2.4%. Next, the metal layer and the liquid crystal polymer film having the intermediate layer and the rolled copper foil were subjected to heat treatment at 250 DEG C for 10800 seconds in a vacuum atmosphere. Thus, a metal laminated film (layer configuration: rolled copper foil/intermediate layer (copper layer)/liquid crystal polymer film/intermediate layer (copper layer)/rolled copper foil) was produced.

(Example 2)

First, a liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-25) having a thickness of 25 μm was prepared, and a rolled copper foil having a thickness of 16 μm was prepared as a metal foil. Next, after one surface of the liquid crystal polymer film was activated by sputter etching, an intermediate layer (copper layer) containing copper (thickness of 40 nm) was formed by sputtering on the activated surface. Next, the surface of the intermediate layer and the surface of the rolled copper foil are activated by sputter etching, and the activated surface of the rolled copper foil is in contact with the activated surface of the intermediate layer, and then the intermediate layer and the rolled copper foil are subjected to a preload of 1.5 tf/cm. The activated surfaces were roll bonded to each other. The reduction ratio was 2.4%. Next, the metal layer and the liquid crystal polymer film having the intermediate layer and the rolled copper foil were subjected to heat treatment at 280 DEG C for 10800 seconds in a vacuum atmosphere. Thus, a metal laminated film (layer configuration: rolled copper foil/intermediate layer (copper layer)/liquid crystal polymer film) was produced.

(Example 3)

A metal laminated film (layer configuration: rolled copper foil/intermediate layer (copper layer)/liquid crystal polymer film) was produced in the same manner as in Example 2 except that the heat treatment after rolling bonding was performed in an N ₂ atmosphere.

(Example 4)

Except for the fact that a first intermediate layer (nickel layer) containing nickel (thickness: 40 nm) and a second intermediate layer (copper layer) containing copper (thickness: 40 nm) were formed by sputtering in this order on one surface of the liquid crystal polymer film. A metal laminated film (layer structure: rolled copper foil/second intermediate layer (copper layer)/first intermediate layer (nickel layer)/liquid crystal polymer film) was produced in the same manner as in Example 3.

(Example 5)

First, a liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-25) with a thickness of 25 μm was prepared, and an ultra-thin copper layer with a thickness of 1.5 μm was applied to a carrier layer containing copper with a thickness of 18 μm as a metal foil and a release layer (organic release layer) interposed therebetween. A copper foil with a carrier layer (MT18FL manufactured by Mitsui Mining and Mining Co., Ltd.) in which a roughened particle layer and an anticorrosive layer were provided on the surface of the ultrathin copper layer was prepared. Next, after one surface of the liquid crystal polymer film was activated by sputter etching, an intermediate layer (copper layer) containing copper (thickness of 40 nm) was formed by sputtering on the activated surface. Next, the surface of the intermediate layer and the surface of the rolled copper foil are activated by sputter etching, and the activated surface of the rolled copper foil is in contact with the activated surface of the intermediate layer, and then the intermediate layer and the rolled copper foil are The activated surfaces were roll bonded to each other. The reduction ratio was 2.4%. Next, the metal layer and the liquid crystal polymer film having the copper foil with the intermediate layer and the carrier layer were subjected to heat treatment at 250 DEG C for 10800 seconds in a vacuum atmosphere. Thus, a metal laminated film (layer configuration: copper foil with a carrier layer/intermediate layer (copper layer)/liquid crystal polymer film) was produced.

(Example 6)

The use of copper foil with a carrier layer as metal foil, in which an ultra-thin copper layer with a thickness of 5.0 μm is provided on a carrier layer containing copper with a thickness of 18 μm through a peeling layer (organic peeling layer), and only a rust-proof layer is provided on the surface of the ultra-thin copper layer. A metal laminated film (layer structure: copper foil with carrier layer/intermediate layer (copper layer)/liquid crystal polymer film) was produced in the same manner as in Example 5, except that heat treatment after roll bonding was performed at 270°C.

(Example 7)

First, a liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-25) with a thickness of 25 μm was prepared, and an ultra-thin copper layer with a thickness of 2.0 μm was applied to a carrier layer containing copper with a thickness of 18 μm as a metal foil and a release layer (inorganic release layer) interposed therebetween. was provided, and a copper foil with a carrier layer was prepared in which only an antirust layer was provided on the surface of the ultrathin copper layer. Next, after one surface of the liquid crystal polymer film was activated by sputter etching, an intermediate layer (copper layer) containing copper (thickness of 40 nm) was formed by sputtering on the activated surface. Next, the surface of the middle layer and the surface of the ultra-thin copper layer are activated by sputter etching, and the activated surface of the rolled copper foil is brought into contact with the activated surface of the middle layer, and then the middle layer and the ultra-thin copper layer are applied with a line load of 1.5 tf/cm. The activated surfaces of the layers were roll bonded to each other. The reduction ratio was 2.4%. Next, the metal layer and the liquid crystal polymer film having the copper foil with the intermediate layer and the carrier layer were subjected to heat treatment in an N ₂ atmosphere at 280° C. for 10800 seconds. Thus, a metal laminated film (layer structure: copper foil with carrier layer/intermediate layer (copper layer)/liquid crystal polymer film) was produced.

(Example 8)

Except for the fact that a first intermediate layer (nickel layer) containing nickel (thickness: 40 nm) and a second intermediate layer (copper layer) containing copper (thickness: 40 nm) were formed by sputtering in this order on one surface of the liquid crystal polymer film. A metal laminated film (layer configuration: copper foil with a carrier layer/second intermediate layer (copper layer)/first intermediate layer (nickel layer)/liquid crystal polymer film) was produced in the same manner as in Example 7.

(Comparative Example 1)

By the thermal lamination method, on both surfaces of a 50 μm thick liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-50), a rolled copper foil with a thickness of 12 μm having a treatment layer made of a roughened particle layer or the like on one side was thermally compressed one by one. By doing so, a metal laminated film (layer configuration: rolled copper foil/liquid crystal polymer film/rolled copper foil) was produced. The metal laminated film is formed by sandwiching the liquid crystal polymer film between two rolled copper foils so that the treated layer surfaces of the two rolled copper foils are in contact with both surfaces of the liquid crystal polymer film, and heating the liquid crystal polymer film to a temperature of 310 ° C. or higher. The surfaces of the liquid crystal polymer film and the rolled copper foil are bonded together by hot-pressing the polymer film and the rolled copper foil.

(Comparative Example 2)

By the thermal lamination method, on both surfaces of a 50 μm thick liquid crystal polymer film (Kuraray Co., Ltd. Baxter CTQ-50), one sheet of 12 μm thick electrolytic copper foil having a treatment layer made of a roughened particle layer or the like is thermally compressed on one side. By doing so, a metal laminated film (layer structure: electrodeposited copper foil/liquid crystal polymer film/electrolytic copper foil) was produced. The metal laminated film is formed by sandwiching the liquid crystal polymer film between two sheets of electrodeposited copper foil so that the surfaces of the treated layers of the two sheets of electrodeposited copper foil are in contact with each other on both surfaces of the liquid crystal polymer film, and heating the liquid crystal polymer film to a temperature of 310 ° C. or higher. The surfaces of the liquid crystal polymer film and the electrodeposited copper foil are bonded together by hot-pressing the polymer film and the electrodeposited copper foil.

[Orientation Degree (F) of Liquid Crystal Polymer Film]

The copper layer and the electrodeposited copper foil were chemically etched away from the metal laminated films of Example 1 and Comparative Example 2 with a ferric chloride solution or the like, and a slice of about 4 μm in size was cut in the width direction from the liquid crystal polymer film after removing them. and the degree of orientation (F) of each region in the thickness direction of each slice was measured. Further, for comparison, slices of about 4 μm in dimension in the width direction were cut out from the same untreated liquid crystal polymer films used in the preparation of the metal laminated films of Examples 1 and 2, and each area in the thickness direction of the slices was cut out. Orientation (F) of was measured. Fig. 3 is a schematic diagram showing a measurement area of the degree of orientation (F) in a section of a liquid crystal polymer film.

In the measurement of the degree of orientation (F), as shown in FIG. 3, in a cross section (vertical cross section) perpendicular to the cut surface of the liquid crystal polymer film and parallel to the MD, the thickness direction distances from the surface were 5 μm, 15 μm, 25 μm, and 35 μm. , and each rectangular region located at 45 μm as an aperture, measuring the infrared dichroic ratio (D) by micro-infrared spectroscopic analysis in each measurement region, and measuring the degree of orientation (F) from the infrared dichroic ratio (D) was calculated. The used measuring device, measuring method, and polarizer, and measuring conditions are as follows.

Measuring device: Cary670/620 by Agilent Technology Co., Ltd.

Measurement method: polarized light microscopic FT-IR analysis/transmission method

Aperture size: MD length 100 μm × thickness direction length 10 μm

Polarizer: Substrate KRS-5

Resolution: 4 cm ^-1

The multiplication (integration) number of times: 128 times

The infrared dichroic ratio (D) was determined from the intensity of a peak at 1601 cm ^-1 that is attributed to the C=C stretching vibration of the benzene ring and has a transition moment parallel to the molecular chain. Specifically, the peak intensity (A||) of the infrared transmission spectrum measured in the polarization direction parallel to the MD and the peak intensity (A⊥) of the infrared transmission spectrum measured in the polarization direction perpendicular to the MD were 1601 cm ^-1 A straight line connecting the 1618.9 cm ^{−1 and 1572.4 cm −1 points} of the spectrum was measured as a baseline using the peak as a quantification peak, and then the infrared dichroic ratio (D) was obtained by Equation (1). Further, the orientation degree (F) to MD was calculated by Formula (2).

[Equation 3]

[Equation 4]

Peak intensity ( ^A⊥ ) and intensity (A⊥), infrared dichroic ratio (D), and Table 1 shows the average value of the degree of orientation (F) and the degree of orientation (F) in the thickness direction for each slice. Also, FIG. 4 is a graph showing the degree of orientation (F) for each position of a measurement area in slices of untreated and liquid crystal polymer films of Example and Comparative Example 2.

[Table 1]

As shown in Table 1 and FIG. 4, in the liquid crystal polymer film slices of Example 1 and Comparative Example 2, the degree of orientation (F) in the entire thickness direction was lower than that of the untreated liquid crystal polymer film slices. Comparing the slices of the liquid crystal polymer films of Example 1 and Comparative Example 2, the degree of orientation (F) of the slices of the liquid crystal polymer film of Example 1 was higher in the entire thickness direction than that of the liquid crystal polymer film of Comparative Example 2. In addition, in the slice of the untreated liquid crystal polymer film of Example 1, unlike the slice of the liquid crystal polymer film of Comparative Example 2, the measurement area located at the center side in the thickness direction (distance in the thickness direction from the surface of the slice: 15 μm, 25 μm and 35 μm) tended to be higher than the orientation degree of the measurement area located on the surface side in the thickness direction (distance in the thickness direction from the surface of the section: 5 μm and 45 μm).

[Dielectric properties of liquid crystal polymer film]

Example 1, Comparative Example 1, and Comparative Example 2 were chemically etched away from the metal laminated films of Example 1, Comparative Example 1, and Comparative Example 2 by chemically etching the copper layer, the rolled copper foil, and the electrodeposited copper foil, respectively, with a ferric chloride solution or the like. A liquid crystal polymer film for measuring dielectric properties of Example 2 was prepared. and untreated liquid crystal polymer films identical to those used in the fabrication of the metal laminated films of Example 1, Comparative Example 1, and Comparative Example 2, and the liquid crystal polymer for measuring dielectric properties of Example 1, Comparative Example 1, and Comparative Example 2. For the film, the thickness and relative permittivity and dielectric loss tangent were measured. The relative permittivity and dielectric loss tangent were measured using an open resonance method at a measurement frequency of 28 GHz and using a relative permittivity/dissipation tangent measurement system (DPS03 manufactured by Kicom Corporation). Table 2 shows these measurement results.

[Table 2]

As shown in Table 2, the increase in dielectric loss tangent of the liquid crystal polymer films of Comparative Examples 1 and 2 relative to the untreated liquid crystal polymer film exceeded 14%, whereas that of Example 1 relative to the untreated liquid crystal polymer film The increase in the dielectric loss tangent of the liquid crystal polymer film was less than 5%.

[Bond strength between metal layer and liquid crystal polymer film]

For the metal laminated films of Examples 1 to 8 and Comparative Examples 1 and 2, the bonding strength between the metal layer and the liquid crystal polymer film was measured by the measurement method described in the section "A. Metal laminated film 3. Metal laminated film". In addition, for the metal laminated films of Examples 5 to 8, the carrier layer and peeling layer of the copper foil with a carrier layer were removed to expose the ultrathin copper layer, and then the metal layer described in the section "A. Metal laminated film 3. Metal laminated film". Similar to the method of electrolytic plating on the surface, electrolytic copper plating was applied to the surface of the ultra-thin copper layer to prevent cutting of the thin and fragile ultra-thin copper layer, and after increasing the thickness of the ultra-thin copper layer, the bonding strength between the metal layer and the liquid crystal polymer film was measured. . Table 3 shows these measurement results.

[Table 3]

As shown in Table 3, all of the metal laminated films of Examples 1 to 8 had a bonding strength of 2.0 N/cm or more between the metal layer and the liquid crystal polymer film. In addition, in the metal laminated films of Examples 1 to 8, the bonding strength tended to increase as the heat treatment temperature increased.

1A metal laminated film
10 metal layer
12 copper foil (metal foil)
12a Copper foil surface
14 middle layer
14a surface opposite to the liquid crystal polymer film side of the intermediate layer
20 liquid crystal polymer film
One surface of the 20a liquid crystal polymer film
All publications, patents and patent applications cited in this specification are incorporated herein by reference as is.

Claims (13)

A metal layer is laminated on at least one surface of the liquid crystal polymer film,
The metal laminate film, characterized in that the degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film is 0.31 or more. A metal layer is laminated on at least one surface of the liquid crystal polymer film,
The degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film is 77% or more of the degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film before the metal layer is laminated. Metal laminated film, characterized in that. According to claim 1 or 2,
The metal laminate film, characterized in that the average of the degree of orientation (F) in the thickness direction in the liquid crystal polymer film is 0.31 or more. According to any one of claims 1 to 3,
A metal laminated film, characterized in that the dielectric loss tangent of the liquid crystal polymer film is less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated. According to any one of claims 1 to 4,
The metal laminated film, characterized in that the bonding strength between the metal layer and the liquid crystal polymer film is 2.0 N / cm or more. According to any one of claims 1 to 5,
The metal laminate film characterized in that the metal layer has a metal foil. The method of claim 6,
The metal laminated film, characterized in that the metal layer further comprises an intermediate layer containing a metal between the liquid crystal polymer film and the metal foil. The method of claim 7,
Characterized in that the intermediate layer includes any one type of metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver, and gold, or an alloy containing the metal metal laminated film. According to any one of claims 6 to 8,
The metal laminate film characterized in that the said metal foil is copper foil, copper alloy foil, or copper foil with a carrier. As a manufacturing method of the metal laminated film according to claim 7,
A step of preparing a liquid crystal polymer film and a metal foil;
laminating an intermediate layer containing a metal on at least one surface of the liquid crystal polymer film;
activating the surface of the intermediate layer by sputter etching;
A step of activating the surface of the metal foil by sputter etching;
A step of rolling bonding the activated surfaces of the intermediate layer and the metal foil to each other at a reduction ratio of 0 to 30%;
A metal-laminated film having a step of heat-treating the intermediate layer, the metal layer having the metal foil, and the liquid crystal polymer film bonded by roll at a temperature equal to or higher than the melting point of the liquid crystal polymer film -100°C and equal to or lower than the melting point -10°C. manufacturing method. The method of claim 10,
The method of manufacturing a metal laminate film, characterized in that the degree of orientation (F) of the central portion in the thickness direction in the liquid crystal polymer film after the heat treatment is 0.31 or more. According to claim 10 or 11,
The orientation degree (F) of the central portion in the thickness direction of the liquid crystal polymer film after the heat treatment is 77% or more of the orientation degree (F) of the central portion in the thickness direction of the liquid crystal polymer film before the metal layer is laminated. A method for producing a laminated film. According to any one of claims 10 to 12,
The method of manufacturing a metal laminate film, characterized in that the dielectric loss tangent of the liquid crystal polymer film after the heat treatment is less than 114% of the dielectric loss tangent of the liquid crystal polymer film before the metal layer is laminated.

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