WO2020004338A1

WO2020004338A1 - Resin-attached metal foil

Info

Publication number: WO2020004338A1
Application number: PCT/JP2019/024975
Authority: WO
Inventors: 敦美山邊; 細田　朋也; 渉笠井; 達也寺田
Original assignee: Ａｇｃ株式会社
Priority date: 2018-06-27
Filing date: 2019-06-24
Publication date: 2020-01-02
Also published as: CN112334301A; JPWO2020004338A1; KR20210022533A; TWI809135B; TW202010636A; JP7243724B2

Abstract

The purpose of the present invention is to provide: a resin-attached metal foil which has a non-porous resin layer including a fluoropolymer and which has high peeling strength, is hard to warp, and has excellent electric characteristics; and a method for manufacturing a print wiring board using the resin-attached metal foil. This resin-attached metal foil has: a metal foil with an uneven surface; and a non-porous resin layer which includes a tetra fluoro ethylene-based polymer and which abuts the uneven surface of the metal foil, wherein a void is present in a portion of the interface between the metal foil and the non-porous resin layer.

Description

Metal foil with resin

The present invention relates to a metal foil with resin.

A resin-coated metal foil having an insulating resin layer on the surface of the metal foil is used as a printed wiring board by processing the metal foil by etching or the like.
Printed wiring boards used for transmitting high-frequency signals are required to have excellent transmission characteristics. In order to enhance the transmission characteristics, it is necessary to use a resin having a low relative dielectric constant and a low dielectric loss tangent as the insulating resin layer of the printed wiring board. As a resin having a small relative dielectric constant and a small dielectric loss tangent, a fluoropolymer such as polytetrafluoroethylene (PTFE) is known.

Patent Document 1 discloses a resin-attached metal foil having a fluoropolymer resin layer on the surface of a metal foil treated with a silane coupling agent. Patent Document 2 discloses a resin-attached metal foil having a porous resin layer made of a fluoropolymer on the surface of the metal foil. Patent Document 3 discloses a resin-attached metal foil having a resin layer made of a surface-modified fluoropolymer on the surface of the metal foil.

International Publication No. WO 2014/192718 JP 2016-044333 A JP 2016-225524 A

The resin-coated metal foils described in Patent Literatures 1 to 3 are prepared by adhering a metal foil and a fluoropolymer resin layer in order to suppress transmission loss due to a skin effect when used as a high-frequency printed wiring board. The peel strength of the resin layer is increased. However, a resin-attached metal foil in which a fluoropolymer resin layer having a large linear expansion coefficient is closely attached to a metal foil is likely to be warped due to expansion and contraction of the fluoropolymer. Therefore, when forming a transmission circuit by etching the metal foil of the resin-coated metal foil and processing it into a printed wiring board by soldering by the reflow method, the warpage of the board becomes a problem, and the printed wiring board is manufactured efficiently. Can not. As described above, in the case of a resin-coated metal foil having a fluoropolymer resin layer on the surface of the metal foil, it is difficult to achieve both peel strength of the resin layer and warpage of the resin-coated metal foil when processing the printed wiring board. .

The object of the present invention is to provide a resin-attached metal foil having a non-porous resin layer containing a fluoropolymer, which has a high peel strength, is hardly warped, and has excellent electric properties.

The present invention has the following aspects.
[1] A metal foil having an uneven surface, and a non-porous resin layer containing a tetrafluoroethylene-based polymer in contact with the uneven surface of the metal foil, and an interface between the metal foil and the non-porous resin layer Metallic foil with resin in which voids exist in a part of.
[2] The resin-attached metal foil according to [1], wherein the void exists in a concave portion of the uneven surface of the metal foil.
[3] The resin-attached metal foil according to [1] or [2], wherein a warp rate of the resin-attached metal foil is 5% or less.
[4] The resin-attached metal foil according to any one of [1] to [3], wherein a peel strength between the metal foil and the non-porous resin layer is 5 N / cm or more.
[5] The thickness of the metal foil is 5 to 25 μm, the thickness of the non-porous resin layer is 0.05 to 100 μm, and the thickness of the non-porous resin layer with respect to the thickness of the metal foil The resin-coated metal foil according to any one of [1] to [4], wherein the ratio is 0.1 to 10.0.
[6] The resin-coated metal foil according to any one of [1] to [5], wherein the surface of the uneven surface of the metal foil has a ten-point average roughness of 0.2 to 4 μm.
[7] The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having a temperature range exhibiting a storage elastic modulus of 0.1 to 5.0 MPa at 260 ° C. or lower and a melting point exceeding 260 ° C. [1] ] A metal foil with resin according to any one of [6] to [6].
[8] A polymer in which the tetrafluoroethylene-based polymer includes a unit based on tetrafluoroethylene and a unit based on at least one monomer selected from the group consisting of perfluoro (alkyl vinyl ether), hexafluoropropylene, and fluoroalkylethylene. The metal foil with resin according to any one of [1] to [7].
[9] The tetrafluoroethylene-based polymer is a polymer having at least one functional group selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group, an amide group, an amino group, and an isocyanate group. ] A metal foil with resin according to any one of [8] to [8].
[10] A method for manufacturing a printed wiring board, wherein a transmission circuit is formed by etching a metal foil of the resin-attached metal foil according to any one of [1] to [9] to obtain a printed wiring board.

According to the present invention, it is possible to provide a resin-attached metal foil having a non-porous resin layer containing a fluoropolymer, which has a high peel strength, is hardly warped, and has excellent electric properties.
The resin-attached metal foil of the present invention has a high peel strength of the non-porous resin layer containing the fluoropolymer and is hardly warped, and thus can be suitably used as a material for a high-frequency printed wiring board in which loss due to the skin effect is suppressed.

3 is an SEM image of a cross section of the metal foil with resin of Example 1.

The following terms have the following meanings:
The “arithmetic average roughness (Ra)” is a value obtained by measuring the surface of the non-porous resin layer in a range of 1 μm ² using an atomic force microscope (AFM).
"Ten-point average roughness (Rz _JIS )" is a value specified in Annex JA of JIS B 0601: 2013.
"The storage elastic modulus of a polymer" is a value measured based on ISO 6721-4: 1994 (JIS K 7244-4: 1999).
"The melting temperature (melting point) of a polymer" is the temperature corresponding to the maximum value of the melting peak of a polymer measured by differential scanning calorimetry (DSC).
“Powder D50” is a 50% volume-based cumulative diameter of the powder determined by a laser diffraction / scattering method. That is, the particle size distribution of the powder is measured by the laser diffraction / scattering method, and the cumulative curve is obtained by setting the total volume of the powder particle population to 100%, and the particle diameter at the point where the cumulative volume becomes 50% on the cumulative curve. is there.
“D90 of the powder” is a 90% diameter based on the volume of the powder obtained in the same manner as in the above D50.
The "warp rate of the metal foil with resin" is obtained by cutting a square test piece of 180 mm square from the metal foil with resin and measuring the test piece according to JIS C 6471: 1995 (corresponding international standard IEC 249-1: 1982). Is a value measured according to
"Relative permittivity" and "Dielectric loss tangent" are each maintained at a temperature of 23 ° C ± 2 ° C and a relative humidity of 50% ± 5% RH by a transformer bridge method based on ASTM D150. It is a value obtained at 20 GHz in the test environment.
The “heat-resistant resin” is a polymer compound having a melting point of 280 ° C. or more, or a polymer compound having a maximum continuous use temperature of 121 ° C. or more specified in JIS C 4003: 2010 (IEC 60085: 2007).
The “unit” in the polymer may be an atomic group formed directly from one molecule of the monomer by the polymerization reaction, and the polymer obtained by the polymerization reaction is treated by a predetermined method to convert a part of the structure. It may be the above atomic group. In addition, a unit based on the monomer A may be represented as a “monomer A unit”.

The reason why the resin-attached metal foil of the present invention has high peel strength and is hardly warped is not necessarily clear, but is considered as follows.
The non-porous resin layer in the present invention is a non-porous dense layer containing a tetrafluoroethylene-based polymer having a large coefficient of linear expansion (hereinafter also referred to as “TFE-based polymer”). The resin-attached metal foil in which the non-porous resin layer is brought into contact with the metal foil is expected to have excellent electrical properties (such as a small relative dielectric constant and a low dielectric loss tangent) and excellent physical properties such as acid resistance (such as etching resistance). On the other hand, it was expected that there was a drawback that it was easily warped.

The present inventors, if a void is present at a part of the interface between the metal foil and the non-porous resin layer of the resin-coated metal foil, the void becomes a buffer for absorbing the expansion and contraction of the TFE-based polymer, We thought that the warpage of the metal foil could be suppressed. On the other hand, when voids were present at a part of the interface, it was expected that the contact area between the metal foil and the non-porous resin layer was reduced, and the peel strength of the non-porous resin layer was also reduced. Then, the present inventors paid attention to the surface shape of the metal foil, and as a result of diligent studies, they found a resin-attached metal foil having excellent physical properties while maintaining the peel strength of the non-porous resin layer. When the metal foil with resin of the present invention is used, a transmission circuit is formed by etching the metal foil, and soldering is performed by reflow method under heating, so that a high-performance printed wiring board can be efficiently manufactured.

The metal foil with resin of the present invention is a non-porous resin containing a metal foil having an uneven surface and a tetrafluoroethylene-based polymer (hereinafter, also referred to as “TFE-based polymer”) in contact with the uneven surface of the metal foil. And a void is present at a part of the interface between the metal foil and the non-porous resin layer. "A gap is present at a part of the interface" means that the metal foil and the non-porous resin layer are in direct contact with each other, and a gap is present at a part of the contact surface.

In the metal foil with resin of the present invention, the metal foil may have an uneven surface on both surfaces, and may have a non-porous resin layer on both surfaces of the metal foil.
The layer structure of the metal foil with resin of the present invention includes metal foil / non-porous resin layer, metal foil / non-porous resin layer / metal foil, non-porous resin layer / metal foil / non-porous resin layer, and the like. No. “Metal foil / non-porous resin layer” indicates that a metal foil and a non-porous resin layer are laminated in this order, and the same applies to other layer configurations.

The peel strength between the metal foil and the non-porous resin layer in the metal foil with resin is preferably 5 N / cm or more, more preferably 7 N / cm or more. The peel strength is preferably 50 N / cm or less.
The warp rate of the resin-attached metal foil of the present invention is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. In this case, the handleability when processing the metal foil with resin into a printed wiring board and the transmission characteristics of the obtained printed wiring board are excellent.

The void in the present invention may be present only at the interface between the metal foil and the non-porous resin layer, or may be present at the interface and the vicinity thereof, or at least at the interface. Is preferred.
When a void is also present near the interface, the distance between the void and the interface is preferably greater than 0 nm and 500 nm or less, more preferably greater than 0 nm and 300 nm or less, and particularly preferably greater than 0 nm and 100 nm or less. preferable. In this case, it is easy to balance physical properties of the TFE-based polymer, which is excellent in electrical properties and acid resistance, with suppression of warpage of the metal foil with resin due to expansion and contraction of the TFE-based polymer. “Distance between void and interface” means the shortest distance between void and interface.

The void is preferably present in the concave portion of the uneven surface of the metal foil in the interface between the metal foil and the non-porous resin layer, from the viewpoint of suppressing the warpage of the metal foil with resin and balancing the electrical characteristics.
It can be said that the resin-attached metal foil of the present invention has a structure in which a nonporous resin layer forms a projection (projection) in contact with a concave portion (dent) of the metal foil. In other words, the void preferably exists at the interface between the depression of the metal foil and the non-porous resin layer in contact with the projection. The existence of such voids can be confirmed by analyzing the cross section of the resin-attached metal foil of the present invention with an SEM image.
The void may be present in each of the convex portion and the concave portion of the uneven surface of the metal foil, but in this case, the number of voids present in the convex portion is smaller than the number of voids present in the concave portion. Is preferred from the viewpoint of maintaining the peel strength between the metal foil and the non-porous resin layer.
Further, from the viewpoint of the peel strength of the non-porous resin layer, it is preferable that the void does not exist in the convex portion of the uneven surface of the metal foil in the interface between the metal foil and the non-porous resin layer.

The metal foil in the present invention has an uneven surface.
The shape of the concave portion and the convex portion of the concave-convex surface is not particularly limited, and may be a column shape, a weight shape, a curved shape, or a constricted shape.
The aspect ratio of the concave portion of the uneven surface of the metal foil is preferably 0.01 or more, more preferably 1.0 or more, particularly preferably 2.0 or more, and preferably 3.0 or more. Most preferred. The upper limit of the aspect ratio is usually 5.0. The aspect ratio of the concave portion is obtained as a ratio of a distance from a lower end of each end of the concave portion to a deepest portion of the concave portion with respect to a distance between both ends forming the concave portion.
The shape of the void can be confirmed by processing a cross section of a metal foil with resin embedded with an epoxy resin by a cross section polisher and observing the cross section with a scanning electron microscope (SEM).

The ten-point average roughness (Rz _JIS ) of the surface of the uneven surface of the metal foil is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 0.2 μm or more. The ten-point average roughness is preferably 4 μm or less, more preferably 1.5 μm or less, and particularly preferably 0.5 μm or less. A preferred embodiment of the ten-point average roughness is 0.2 to 4 μm, a more preferred embodiment is 0.3 to 3.4 μm, and a still more preferred embodiment is 0.7 to 1.5 μm. Can be When the surface Rz _JIS is equal to or more than the lower limit of the above range, the adhesiveness with the non-porous resin layer becomes good. When the Rz _JIS of the surface of the metal foil is equal to or less than the upper limit of the above range, the electric transmission loss caused by the roughness of the metal foil can be reduced.
The thickness of the metal foil is not particularly limited as long as a sufficient function can be exhibited in the application of the resin-attached metal foil, and is preferably 1 to 30 μm, more preferably 5 to 25 μm, and more preferably 8 to 20 μm. It is particularly preferred that there is.

The uneven surface of the metal foil is preferably treated with a silane coupling agent.
The fact that the uneven surface of the metal foil is treated with the silane coupling agent means that the uneven surface of the metal foil is analyzed by X-ray fluorescence spectroscopy (XRF), and the silicon atom and the atom specific to the functional group of the silane coupling agent are used. (Nitrogen atom, sulfur atom, etc.). The detection amounts of silicon atoms and the above atoms may be at least the detection limit, and are preferably detected at 0.01% by mass or more, respectively.
The silane coupling agent treatment of the uneven surface of the metal foil may be performed on the entire uneven surface of the metal foil, or may be performed on a part of the uneven surface of the metal foil. From the viewpoint of the adhesiveness between the metal foil and the non-porous resin layer, it is preferable that the metal foil be part of the uneven surface of the metal foil.

As an aspect in which a part of the uneven surface of the metal foil is treated with the silane coupling agent, without distinction between the concave portion and the convex portion of the uneven surface of the metal foil, a part thereof is treated with the silane coupling agent. Or a mode in which the convex portion of the uneven surface of the metal foil is treated with a silane coupling agent. In the aspect of the silane coupling agent treatment of the uneven surface of the metal foil, the cross section of the metal foil is subjected to elemental analysis by an energy dispersive X-ray spectrometer (EDS), and a silicon atom and an atom (nitrogen specific to a functional group of the silane coupling agent) are analyzed. Atoms, sulfur atoms, etc.).

The metal foil in which a part of the uneven surface is treated with the silane coupling agent is obtained, for example, by spray-drying the silane coupling agent on the uneven surface of the metal foil. Examples of the spray drying method include the treatment methods described in WO-A-2015 / 40988, [0061] to [0064].
As a specific spray-drying method, a treatment solution containing a silane coupling agent and a solvent (alcohol, toluene, hexane, etc.) and the concentration of the silane coupling agent is adjusted to 0.5 to 1.5% by mass. Is sprayed onto the uneven surface of the metal foil and heated at 100 to 130 ° C. for 1 to 10 minutes.

The silane coupling agent is an organic compound having a hydrolyzable silyl group and a reactive group other than the hydrolyzable silyl group (hereinafter, also referred to as “reactive group”). Silanol groups (Si—OH) formed by hydrolysis of hydrolyzable silyl groups interact with the surface of the metal foil to fix the silane coupling agent on the surface of the metal foil, and the reactive group is formed of a non-porous resin. Interaction with the layer surface improves the adhesion between the metal foil and the non-porous resin layer.

As the hydrolyzable silyl group, an alkoxysilyl group is preferable, a trialkoxysilyl group is more preferable, and a trimethoxysilyl group or a triethoxysilyl group is particularly preferable.
As the reactive functional group, hydroxyl group, carboxy group, carbonyl group, amino group, amide group, sulfide group, sulfonyl group, sulfo group, sulfonyldioxy group, epoxy group, acrylic group, methacryl group, mercapto group, isocyanate group, An isocyanurate group and an ureido group are mentioned, a mercapto group, an amino group, an isocyanate group, an isocyanurate group and an ureido group are preferred, a mercapto group and an amino group are more preferred, and a mercapto group is particularly preferred.

Examples of the organic compound having an alkoxysilyl group and an amino group include aminoalkoxysilane, and specific examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N-phenyl-3-amino Propyltrimethoxysilane and the like. As derivatives of aminoalkoxysilanes, ketimines (such as 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine) and salts of aminoalkoxysilanes (N-vinylbenzyl-2-aminoethyl-3) -Aminopropyltrimethoxysilane acetate).
Examples of the organic compound having an alkoxysilyl group and a mercapto group include mercaptoalkoxysilane, and specific examples thereof include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyl (dimethoxy) methylsilane. And the like.

Examples of the material of the metal foil include copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, and titanium alloy.
As the metal foil, a copper foil is preferable. Specific examples of the copper foil include a rolled copper foil and an electrolytic copper foil.
The metal foil is preferably a metal foil having a metal foil main body and a rustproofing layer provided on the non-porous resin layer side of the metal foil main body. When the metal foil has a rust-proofing layer, the surface of the rust-proofing layer is treated with a silane coupling agent.

The rust-proofing layer is selected from the group consisting of nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, and tantalum. A layer containing one or more elements. The rust preventive layer may include the element as a metal or an alloy, or may include the element as an oxide, a nitride, or a silicide.
As the rust-preventive treatment layer, a layer containing cobalt oxide, nickel oxide or metallic zinc, from the viewpoint of suppressing the oxidation of the metal foil for a long time and suppressing the increase in the relative dielectric constant and the dielectric loss tangent of the non-porous resin layer Are preferred, and a layer of metallic zinc is particularly preferred.
A heat-resistant layer may be formed on the metal foil. Examples of the heat-resistant layer include a layer containing the same element as the rust-proofing layer.

The non-porous resin layer in the present invention has substantially no voids except for voids existing in the vicinity of the interface. As the non-porous resin layer which is such a dense resin layer, a resin layer containing a molten resin is preferable, and a resin layer made of a molten resin is preferable.
The thickness of the non-porous resin layer is preferably 0.05 μm or more, more preferably 1 μm or more, and particularly preferably 2 μm or more. The thickness is preferably 100 μm or less, more preferably 10 μm or less, and particularly preferably 7 μm or less. A preferred embodiment of the thickness is 0.05 to 100 μm, and a more preferred embodiment is 6 to 60 μm. Within this range, it is easy to balance the transmission characteristics of the printed wiring board and the suppression of warpage of the metal foil with resin.
When the resin-attached metal foil has a non-porous resin layer on both sides of the metal foil, the composition and thickness of each non-porous resin layer are the same from the viewpoint of suppressing the warpage of the resin-attached metal foil. Is preferred.

Since the metal foil with resin of the present invention is not easily warped, the thickness of the non-porous resin layer can be set to be larger than the thickness of the metal foil.
The ratio of the thickness of the non-porous resin layer to the thickness of the metal foil is preferably from 0.01 to 10.0, more preferably from 0.05 to 7.5, and particularly preferably from 0.2 to 5.0. When the ratio of the thickness of the non-porous resin layer to the thickness of the metal foil is equal to or more than the lower limit of the above range, the electrical characteristics of the TFE-based polymer can be easily sufficiently exhibited. If the ratio of the thickness of the non-porous resin layer to the thickness of the metal foil is equal to or less than the upper limit of the above range, it is more difficult to warp.

The water contact angle on the surface of the non-porous resin layer is preferably from 70 to 100 °, particularly preferably from 70 to 90 °. When the above range is equal to or less than the upper limit, the adhesiveness between the non-porous resin layer and another substrate is more excellent. When the above range is equal to or more than the lower limit, the electrical characteristics (low dielectric loss and low dielectric constant) of the non-porous resin layer are more excellent.
The water contact angle is an angle formed between a water droplet and the surface of the non-porous resin layer when pure water (about 2 μL) is placed on the surface of the non-porous resin layer of the metal foil with resin at 25 ° C.

The relative permittivity of the non-porous resin layer is preferably from 2.0 to 3.5, and more preferably from 2.0 to 3.0. In this case, both the electrical properties and adhesiveness of the non-porous resin layer are excellent, and a resin-attached metal foil can be suitably used for a printed wiring board or the like that requires a low dielectric constant.
Ra on the surface of the non-porous resin layer is less than the thickness of the non-porous resin layer, and preferably 1 to 10 nm. Within this range, it is easy to balance the adhesiveness and workability of another substrate.

The non-porous resin layer in the present invention contains a TFE-based polymer. The TFE-based polymer is preferably a hot-melt TFE-based polymer.
The melting point of the TFE polymer is preferably higher than 260 ° C., more preferably higher than 260 ° C. and 320 ° C. or less, and particularly preferably 275 to 320 ° C. When the melting point of the TFE-based polymer is within the above range, the TFE-based polymer is baked while maintaining the adhesiveness based on its elasticity, so that a dense non-porous resin layer is more easily formed.

The TFE-based polymer preferably has a temperature region exhibiting a storage modulus of 0.1 to 5.0 MPa at 260 ° C. or lower. The storage elastic modulus of the TFE-based polymer is preferably from 0.2 to 4.4 MPa, particularly preferably from 0.5 to 3.0 MPa. Further, the temperature range in which the TFE-based polymer exhibits such storage modulus is preferably from 180 to 260 ° C., particularly preferably from 200 to 260 ° C. In the temperature range, the TFE-based polymer tends to effectively exhibit adhesiveness based on its elasticity.

The TFE-based polymer is a polymer having TFE units. The TFE-based polymer may be a homopolymer of TFE or a copolymer of TFE and another monomer copolymerizable with TFE (hereinafter also referred to as a comonomer). The TFE-based polymer preferably has 75 to 100 mol% of TFE units and 0 to 25 mol% of units based on a comonomer, based on all units constituting the polymer.
Examples of the comonomer include perfluoro (alkyl vinyl ether) (hereinafter also referred to as “PAVE”), fluoroalkylethylene (hereinafter also referred to as “FAE”), hexafluoropropylene (hereinafter also referred to as “HFP”), olefin, and the like. Is mentioned.

Examples of the TFE-based polymer include polytetrafluoroethylene, a copolymer of TFE and ethylene, a copolymer of TFE and propylene, a copolymer of TFE and PAVE, a copolymer of TFE and HFP, a copolymer of TFE and FAE, and a copolymer of TFE and chlorotrifluoroethylene. And copolymers.
PAVE includes CF ₂ = CFOCF ₃ , CF ₂ = CFOCF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₃ (PPVE), CF ₂ = CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ = CFO (CF ₂ ) ₈ F.
As FAE, CH ₂ ＣＨCH (CF ₂ ) ₂ F, CH ₂ ＣＨCH (CF ₂ ) ₃ F, CH ₂ ＣＨCH (CF ₂ ) ₄ F, CH ₂ ＣＦCF (CF ₂ ) ₃ H, CH ₂ ＣＦCF (CF ₂ ) ₄ H.

As a preferable embodiment of the TFE-based polymer, a polymer containing a TFE unit and a unit based on at least one monomer selected from the group consisting of PAVE, HFP and FAE (hereinafter also referred to as “comonomer unit F”) is also exemplified. Can be
The polymer preferably has 90 to 99 mol% of TFE units and 1 to 10 mol% of comonomer units F based on all units constituting the polymer. The polymer may be composed of only the TFE unit and the comonomer unit F, and may further contain other units.

As a preferred embodiment of the TFE-based polymer, from the viewpoint of the adhesiveness between the non-porous resin layer and the metal foil, selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group, an amide group, an amino group and an isocyanate group. And a polymer having TFE units (hereinafter, also referred to as “polymer F ¹ ”) having at least one type of functional group (hereinafter, also referred to as “functional group”).
Functional groups may be contained in the units in the TFE-based polymers may be contained in the end groups of the main chain of the polymer F ^1. Examples of the latter polymer include a polymer having a functional group as a terminal group derived from a polymerization initiator, a chain transfer agent, or the like.
The polymer F ^1, a polymer having the units and TFE units having a functional group are preferred. The polymer F ¹ in this case, further preferably has other units, particularly preferably has a comonomer unit F.
The functional group is preferably a carbonyl group-containing group from the viewpoint of adhesion between the non-porous resin layer and the metal foil. Examples of the carbonyl group-containing group include a carbonate group, a carboxy group, a haloformyl group, an alkoxycarbonyl group, an acid anhydride residue (—C (O) OC (O) —), and a fatty acid residue. Anhydride residues are preferred.

The unit having a functional group is preferably a unit based on a monomer having a functional group, and is a unit based on a monomer having a carbonyl group, a unit based on a monomer having a hydroxy group, a unit based on a monomer having an epoxy group, and an isocyanate group. A unit based on a monomer having a carbonyl group is more preferable, and a unit based on a monomer having a carbonyl group-containing group is particularly preferable.
As the monomer having a carbonyl group-containing group, a cyclic monomer having an acid anhydride residue, a monomer having a carboxy group, a vinyl ester and a (meth) acrylate are preferable, and a cyclic monomer having an acid anhydride residue is particularly preferable.
As the cyclic monomer, itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride (also called hymic anhydride; hereinafter also referred to as “NAH”) and maleic anhydride are preferable.

The polymer ^{F 1,} and the units and TFE units having a functional group, polymers comprising the PAVE units or HFP unit preferable. Specific examples of such polymers ^{F 1,} are polymers described in WO 2018/16644 (X) can be mentioned.
The proportion of TFE units in the polymer ^{F 1} is the total units constituting the polymer ^{F 1,} is preferably 90 to 99 mol%.
Proportion of PAVE units in the polymer ^{F 1} is the total units constituting the polymer ^{F 1,} is preferably 0.5 to 9.97 mol%.
The proportion of units having functional groups in the polymer F ¹ is the total units constituting the polymer F ^1, is preferably 0.01 to 3 mol%.

The method for producing a resin-attached metal foil according to the present invention includes a powder dispersion containing a powder containing a TFE-based polymer (hereinafter also referred to as “F powder”) and a liquid medium on the uneven surface of the metal foil having an uneven surface. Is applied, the liquid medium is removed by heating the powder dispersion on the uneven surface of the metal foil, and then the F powder is baked to obtain the resin-attached metal foil of the present invention. By adjusting the conditions of the method using such a powder dispersion, the state of the void existing at the interface between the metal foil and the non-porous resin layer can be easily adjusted. For example, when the temperature or the time during firing of the F powder is lowered, the number of voids at the interface between the metal foil and the non-porous resin layer tends to increase.

The liquid medium is a dispersion medium, which is a liquid medium that is inert at 25 ° C. and does not react with the F powder, has a lower boiling point than components other than the liquid medium contained in the powder dispersion, and is volatilized by heating or the like. Liquid media that can be removed are preferred.
Examples of the liquid medium include water, alcohols (methanol, ethanol, isopropanol, etc.), nitrogen-containing compounds (N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc.), sulfur-containing compounds (dimethyl Sulfoxides), ethers (diethyl ether, dioxane, etc.), esters (ethyl lactate, ethyl acetate, etc.), ketones (methyl ethyl ketone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, etc.), glycol ethers (ethylene glycol monoisopropyl ether, etc.), Cellosolve (methyl cellosolve, ethyl cellosolve, etc.) and the like. Two or more liquid media may be used in combination.

As the liquid medium, a liquid medium that does not volatilize instantaneously is preferable, a liquid medium having a boiling point of 80 to 275 ° C is preferable, and a liquid medium having a boiling point of 125 to 250 ° C is particularly preferable. Within this range, the stability of the wet film formed from the powder dispersion applied to the surface of the metal foil is high.
As the liquid medium, organic compounds are preferable, and cyclohexane (boiling point: 81 ° C.), 2-propanol (boiling point: 82 ° C.), 1-propanol (boiling point: 97 ° C.), 1-butanol (boiling point: 117 ° C.), 1-butanol Methoxy-2-propanol (boiling point: 119 ° C), N-methylpyrrolidone (boiling point: 202 ° C), γ-butyrolactone (boiling point: 204 ° C), cyclohexanone (boiling point: 156 ° C) and cyclopentanone (boiling point: 131 ° C) Are more preferable, and N-methylpyrrolidone, γ-butyrolactone, cyclohexanone and cyclopentanone are particularly preferable.

The ΔF powder may contain components other than the TFE-based polymer as long as the effects of the present invention are not impaired, but it is preferable that the F-powder be mainly composed of the TFE-based polymer. The content of the TFE-based polymer in the F powder is preferably 80% by mass or more, and particularly preferably 100% by mass.

The D50 of the F powder is preferably from 0.05 to 6.0 μm, more preferably from 0.1 to 3.0 μm, and particularly preferably from 0.2 to 3.0 μm. Within this range, the fluidity and dispersibility of the F powder are good, and the electrical properties (such as a low dielectric constant) and the heat resistance of the non-porous resin layer are most easily exhibited.
The D90 of the F powder is preferably 8 μm or less, more preferably 6 μm or less, and particularly preferably 5 μm or less. The D90 of the powder is preferably at least 0.3 μm, particularly preferably at least 0.8 μm. Within this range, the fluidity and dispersibility of the F powder are good, and the electrical properties (such as a low dielectric constant) and the heat resistance of the non-porous resin layer are most easily exhibited.
The method for producing the F powder is not particularly limited, and the methods described in [0065] to [0069] of WO 2016/017801 can be employed. As the F powder, if desired powder is commercially available, it may be used.

The proportion of the F powder in the powder dispersion is preferably 5 to 60% by mass, particularly preferably 35 to 50% by mass. Within this range, the relative dielectric constant and dielectric loss tangent of the non-porous resin layer can be easily controlled to be low. Further, the powder dispersion has high uniform dispersibility, and the non-porous resin layer has excellent mechanical strength.
The proportion of the liquid medium in the powder dispersion is preferably from 15 to 65% by mass, particularly preferably from 25 to 50% by mass. Within this range, the applicability of the powder dispersion is excellent, and poor appearance of the non-porous resin layer is unlikely to occur.

The powder dispersion may contain other materials as long as the effects of the present invention are not impaired. Other materials may or may not dissolve in the powder dispersion.
The other material may be a non-curable resin or a curable resin.
Examples of the non-curable resin include a heat-meltable resin and a non-meltable resin. Examples of the heat-fusible resin include thermoplastic polyimide. Examples of the non-fusible resin include a cured product of a curable resin.
Examples of the curable resin include a polymer having a reactive group, an oligomer having a reactive group, a low molecular compound, and a low molecular compound having a reactive group. Examples of the reactive group include a carbonyl group-containing group, a hydroxy group, an amino group, and an epoxy group.

As the curable resin, epoxy resin, thermosetting polyimide, polyamic acid as a polyimide precursor, thermosetting acrylic resin, phenol resin, thermosetting polyester resin, thermosetting polyolefin resin, modified polyphenylene ether resin, polyfunctional Examples include a cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, a vinyl ester resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, and a melamine-urea cocondensation resin. Among them, thermosetting polyimide, polyimide precursor, epoxy resin, acrylic resin, bismaleimide resin and polyphenylene ether resin are preferable as thermosetting resin from the viewpoint of being useful for printed wiring board applications, and epoxy resin and polyphenylene ether are preferable. Resins are particularly preferred.

Specific examples of the epoxy resin include naphthalene type epoxy resin, cresol novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, Cresol novolak type epoxy resin, phenol novolak type epoxy resin, alkylphenol novolak type epoxy resin, aralkyl type epoxy resin, biphenol type epoxy resin, dicyclopentadiene type epoxy resin, trishydroxyphenylmethane type epoxy compound, having phenol and phenolic hydroxyl group Epoxidized condensate with aromatic aldehyde, diglycidyl ether of bisphenol, diglycidyl ether of naphthalene diol, phenol Glycidyl ethers, diglycidyl ethers of alcohols, triglycidyl isocyanurate.

As the bismaleimide resin, a resin composition (BT resin) in which a bisphenol A-type cyanate ester resin and a bismaleimide compound are used in combination, which is described in JP-A-7-70315, described in WO2013 / 008667 And the background art.
Polyamic acid typically has a reactive group capable of reacting with the functional groups of the polymer F ^1.
Examples of the diamine and polycarboxylic acid dianhydride forming a polyamic acid include [0020] of Japanese Patent No. 5766125, [0019] of Japanese Patent No. 5766125, and [0055] of Japanese Patent Application Laid-Open No. 2012-145676. , [0057] and the like. Among them, aromatic diamines such as 4,4'-diaminodiphenyl ether and 2,2-bis [4- (4-aminophenoxy) phenyl] propane, and pyromellitic dianhydride, 3,3 ', 4,4 Polyamic acids comprising a combination with an aromatic polycarboxylic dianhydride such as '-biphenyltetracarboxylic dianhydride and 3,3', 4,4'-benzophenonetetracarboxylic dianhydride are preferred.

Examples of the heat-fusible resin include a thermoplastic resin such as thermoplastic polyimide, and a heat-fusible cured product of a curable resin.
As the thermoplastic resin, polyester resin, polyolefin resin, styrene resin, polycarbonate, thermoplastic polyimide, polyarylate, polysulfone, polyarylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyaryletherketone, Polyamide imide, liquid crystalline polyester, polyphenylene ether and the like are mentioned, and thermoplastic polyimide, liquid crystalline polyester and polyphenylene ether are preferable.

Further, other materials that may be contained in the powder dispersion include a dispersant, a binder, a thixotropy-imparting agent, an antifoaming agent, an inorganic filler, a reactive alkoxysilane, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, and heat. Stabilizers, lubricants, antistatic agents, brighteners, coloring agents, conductive agents, release agents, surface treatment agents, viscosity modifiers, flame retardants and the like are also included.

The method of applying the powder dispersion to the uneven surface of the metal foil may be any method that forms a stable wet film made of the powder dispersion on the uneven surface of the metal foil after application, such as a spray method, a roll coating method, and a spin coating method. Coating method, gravure coating method, microgravure coating method, gravure offset method, knife coating method, kiss coating method, bar coating method, die coating method, fountain Meyer bar method, slot die coating method and the like.

After the powder dispersion is applied to the uneven surface of the metal foil, the TFE-based polymer has a storage elastic modulus of 0.1 to 5.0 MPa at a temperature within a temperature range (hereinafter, also referred to as “holding temperature”). It is preferable to hold the metal foil. The holding temperature indicates the temperature of the atmosphere.
In addition, before providing the metal foil in the temperature range, the state of the wet film may be adjusted by heating the metal foil at a temperature lower than the temperature range. The adjustment of the state of the wet film is performed to such an extent that the liquid medium does not completely volatilize, and is usually performed to the extent that 50% by mass or less of the liquid medium is volatilized.

The holding after the application of the powder dispersion may be performed in one stage, or may be performed in multiple stages at different temperatures.
Examples of the holding method include a method using an oven, a method using a ventilation drying oven, and a method of irradiating heat rays such as infrared rays.
The atmosphere in the holding may be under normal pressure or reduced pressure. The holding atmosphere may be any of an oxidizing gas atmosphere such as an oxygen gas atmosphere, a reducing gas atmosphere such as a hydrogen gas atmosphere, and an inert gas atmosphere such as a helium gas, a neon gas, an argon gas, and a nitrogen gas.
As an atmosphere for the holding, an atmosphere containing an oxygen gas is preferable from the viewpoint of improving the adhesiveness of the non-porous resin layer.
The oxygen gas concentration (by volume) in an atmosphere containing oxygen gas is preferably from 1 × 10 ² to 3 × 10 ⁵ ppm, particularly preferably from 0.5 × 10 ³ to 1 × 10 ⁴ ppm. Within this range, it is easy to balance the adhesiveness of the non-porous resin layer and the suppression of oxidation of the metal foil.

The holding temperature is preferably from 150 to 260 ° C, particularly preferably from 200 to 260 ° C.
The holding time at the holding temperature is preferably from 0.1 to 10 minutes, particularly preferably from 0.5 to 5 minutes.
When holding, after holding, the TFE-based polymer is fired to form a non-porous resin layer on the surface of the metal foil. The firing temperature indicates the temperature of the atmosphere during firing of the TFE-based polymer. In the present invention, the fusion of the TFE-based polymer proceeds in a state where the F powder is densely packed, so that a non-porous resin layer having excellent homogeneity is formed, and the resin-attached metal foil is not easily warped. If the powder dispersion contains a thermofusible resin, a non-porous resin layer composed of a mixture of a TFE-based polymer and a heat-fusible resin is formed. If the powder dispersion contains a thermosetting resin, a TFE-based polymer is formed. A non-porous resin layer composed of a cured product of the thermosetting resin is formed.

Examples of the heating method include a method using an oven, a method using a ventilation drying oven, and a method of irradiating heat rays such as infrared rays. In order to increase the smoothness of the surface of the non-porous resin layer, pressure may be applied with a heating plate, a heating roll, or the like. As a heating method, a method of irradiating far-infrared rays is preferable because it can be fired in a short time and the far-infrared ray furnace is relatively compact. The heating method may be a combination of infrared heating and hot air heating.
The effective wavelength band of the far infrared ray is preferably 2 to 20 μm, more preferably 3 to 7 μm, from the viewpoint of promoting uniform fusion of the TFE-based polymer.

The atmosphere in the firing may be under normal pressure or under reduced pressure. The atmosphere in the firing may be any of an oxidizing gas atmosphere such as an oxygen gas, a reducing gas atmosphere such as a hydrogen gas, and an inert gas atmosphere such as a helium gas, a neon gas, an argon gas, and a nitrogen gas. From the viewpoint of suppressing the oxidative deterioration of the metal foil and the non-porous resin layer to be formed, the atmosphere is preferably a reducing gas atmosphere or an inert gas atmosphere.
As the atmosphere for firing, a gas atmosphere composed of an inert gas and having a low oxygen gas concentration is preferable, and a gas atmosphere composed of nitrogen gas and having an oxygen gas concentration (by volume) of less than 500 ppm is preferable. The oxygen gas concentration (by volume) is particularly preferably 300 ppm or less. Further, the oxygen gas concentration (based on volume) is usually 1 ppm or more.
The firing temperature is preferably higher than 320 ° C., particularly preferably 330 to 380 ° C. In this case, the TFE-based polymer more easily forms a dense non-porous resin layer.
The holding time at the firing temperature is preferably from 30 seconds to 5 minutes, and particularly preferably from 1 to 2 minutes.

(4) When the resin layer of the resin-attached metal foil is a conventional insulating material (a cured product of a thermosetting resin such as polyimide), long-time heating is required to cure the thermosetting resin. On the other hand, in the present invention, the non-porous resin layer can be formed by heating for a short time by fusing the TFE-based polymer. When the powder dispersion contains a thermosetting resin, the firing temperature can be lowered. As described above, the resin-attached metal foil of the present invention has a small heat load on the metal foil when the non-porous resin layer is formed at the time of manufacturing, and has a small damage to the metal foil.

In the metal foil with resin of the present invention, in order to control the linear expansion coefficient of the non-porous resin layer or to further improve the adhesiveness of the non-porous resin layer, the surface of the non-porous resin layer Processing may be performed.
Surface treatment methods for the surface of the non-porous resin layer include annealing treatment, corona discharge treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, UV ozone treatment, excimer treatment, chemical etching, silane coupling agent treatment, and fine rough surface. And the like.
The temperature in the annealing treatment is preferably from 80 to 190 ° C., particularly preferably from 120 to 180 ° C.
The pressure in the annealing treatment is preferably 0.001 to 0.030 MPa, particularly preferably 0.005 to 0.015 MPa.
The annealing time is preferably from 10 to 300 minutes, particularly preferably from 30 to 120 minutes.

Examples of the plasma irradiation apparatus in the plasma processing include a high-frequency induction method, a capacitive coupling electrode method, a corona discharge electrode-plasma jet method, a parallel plate type, a remote plasma type, an atmospheric pressure plasma type, an ICP type high density plasma type, and the like. .
Examples of a gas used for the plasma treatment include an oxygen gas, a nitrogen gas, a rare gas (eg, argon), a hydrogen gas, and an ammonia gas, and a rare gas and a nitrogen gas are preferable. Specific examples of the gas used for the plasma treatment include argon gas, a mixed gas of hydrogen gas and nitrogen gas, and a mixed gas of hydrogen gas, nitrogen gas, and argon gas.
The atmosphere in the plasma treatment is preferably an atmosphere having a volume fraction of a rare gas or a nitrogen gas of 70% by volume or more, and particularly preferably an atmosphere having a volume fraction of 100% by volume. Within this range, it is easy to form fine irregularities on the surface of the non-porous resin layer.

The metal foil with resin of the present invention described above has a high peel strength of the non-porous resin layer and is hardly warped. Therefore, it can be easily laminated with another substrate.
Other substrates include a heat-resistant resin film, a prepreg that is a precursor of a fiber-reinforced resin plate, a laminate having a heat-resistant resin film layer, a laminate having a prepreg layer, and the like.
The prepreg is a sheet-like substrate in which a thermosetting resin or a thermoplastic resin is impregnated into a base material (tow, woven fabric, or the like) of a reinforcing fiber (glass fiber, carbon fiber, or the like).
The heat-resistant resin film is a film containing at least one kind of heat-resistant resin, and may be a single-layer film or a multilayer film.

Examples of the heat-resistant resin include polyimide, polyarylate, polysulfone, polyallylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallyletherketone, polyamideimide, and liquid crystalline polyester.

As a method of laminating another base material on the surface of the non-porous resin layer of the metal foil with resin of the present invention, a method of hot pressing the metal foil with resin and another substrate is exemplified.
When the other substrate is a prepreg, the pressing temperature is preferably equal to or lower than the melting point of the TFE-based polymer, more preferably from 120 to 300 ° C, and particularly preferably from 160 to 220 ° C. Within this range, the non-porous resin layer and the prepreg can be firmly bonded while suppressing thermal deterioration of the prepreg.
When the substrate is a heat-resistant resin film, the pressing temperature is preferably from 310 to 400 ° C. Within this range, the non-porous resin layer and the heat-resistant resin film can be firmly bonded while suppressing the thermal deterioration of the heat-resistant resin film.

The hot pressing is preferably performed under a reduced pressure atmosphere, and particularly preferably performed at a degree of vacuum of 20 kPa or less. Within this range, the incorporation of bubbles into the interface between the non-porous resin layer and the substrate in the laminate can be suppressed, and deterioration due to oxidation can be suppressed.
In the case of hot pressing, it is preferable to raise the temperature after reaching the above-mentioned degree of vacuum. If the temperature is raised before reaching the degree of vacuum, the non-porous resin layer is pressed in a softened state, that is, in a state having a certain degree of fluidity and adhesion, causing bubbles.
The pressure in the hot press is preferably 0.2 MPa or more. Further, the upper limit of the pressure is preferably 10 MPa or less. Within this range, the non-porous resin layer and the substrate can be firmly adhered while suppressing damage to the substrate.

樹脂 The resin-attached metal foil and the laminate thereof of the present invention can be used as a flexible copper-clad laminate or a rigid copper-clad laminate for the production of printed wiring boards. Since the metal foil with resin of the present invention has a high peel strength of the non-porous resin layer and is hard to be warped, it can be suitably used as a material for a high-frequency printed wiring board in which loss due to a skin effect is suppressed.

For example, a method of processing the metal foil of the resin-coated metal foil of the present invention into a transmission circuit (pattern circuit) having a predetermined pattern by an etching process or the like, or a method of electroplating the resin-coated metal foil of the present invention (semi-additive method (SAP)) ), A modified semi-additive method (MSAP method), etc.), a printed wiring board can be manufactured from the resin-attached metal foil of the present invention.

In manufacturing a printed wiring board, after forming a transmission circuit, an interlayer insulating film may be formed over the transmission circuit, and the transmission circuit may be further formed over the interlayer insulating film. The interlayer insulating film can be formed by, for example, the powder dispersion described above.
In manufacturing a printed wiring board, a solder resist may be laminated on a transmission circuit. The solder resist can be formed by, for example, the powder dispersion described above.
In manufacturing a printed wiring board, a coverlay film may be laminated on a transmission circuit. The cover lay film can be formed by, for example, the powder dispersion described above.

Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited by the following description.
Various evaluations were performed by the following methods.
(Storage modulus of polymer)
Using a dynamic viscoelasticity measurement device (DMS6100, manufactured by SII Nano Technology), the TFE polymer was heated at a rate of 2 ° C./min at a frequency of 10 Hz, a static force of 0.98 N, and a dynamic displacement of 0.035%. And the storage elastic modulus at 260 ° C. was measured.
(Melting point of polymer)
Using a differential scanning calorimeter (DSC-7020, manufactured by Seiko Instruments Inc.), the TFE polymer was heated at a rate of 10 ° C./min and measured.
(Powder D50 and D90)
The powder was dispersed in water and measured using a laser diffraction / scattering type particle size distribution analyzer (LA-920 measuring device manufactured by Horiba, Ltd.).

(Ra on the surface of the non-porous resin layer)
Using an atomic force microscope (manufactured by Oxford Instruments), the probe was set to AC160TS-C3 (tip R <7 nm, spring constant 26 N / m), the measurement mode was set to AC-Air, and the scan rate was set to 1 Hz. Measured.
(Relative permittivity (20 GHz) and dielectric loss tangent (20 GHz))
In a test environment where the temperature is kept within a range of 23 ° C. ± 2 ° C. and the relative humidity is kept within a range of 50% ± 5% RH by a transformer bridge method based on ASTM D150, a dielectric breakdown test apparatus (YSY-243) is used. The relative dielectric constant and the dielectric loss tangent at 20 GHz were determined using -100 RHO (manufactured by Yamayo Testing Machine Co., Ltd.).
(Warpage rate)
A test piece was cut out from the metal foil with resin and measured. As the warpage ratio is smaller, lamination failure when laminating the metal foil with resin with another material can be suppressed, and a composite flat body (printed wiring board or the like) with suppressed warpage and high flatness can be obtained.
(Peel strength)
A position of 50 mm from one end in the length direction of a single-sided copper-clad laminate cut out into a rectangular shape (length 100 mm, width 10 mm) is fixed, and a pull-up speed of 50 mm / min is applied to a single-sided copper-clad laminate from one end in the length direction. The maximum load applied when the metal foil and the non-porous resin layer were peeled off at 90 ° was defined as the peel strength (N / cm).

The TFE polymer and metal foil used are shown below.
Polymer (1): a copolymer containing 97.9 mol%, 0.1 mol%, and 2.0 mol% of a unit based on TFE, a unit based on NAH and a unit based on PPVE in this order, and has a storage elasticity at 260 ° C. A polymer having a rate of 1.0 MPa and a melting point of 300 ° C.
Copper foil (1): a copper foil having an uneven surface, a ten-point surface roughness of the uneven surface being 1.1 μm, and the uneven surface being treated with a silane coupling agent (thickness 18 μm, silicon atomic weight on the foil surface) 0.05 mass%, sulfur atomic weight 0.01 mass%.)

[Example 1]
120 g of a powder (D50: 2.6 μm, D90: 7.1 μm) composed of the polymer (1), 12 g of a nonionic fluorinated surfactant (manufactured by Neos, Phantagent 710FL), and 234 g of methyl ethyl ketone The solution is applied to the surface of the copper foil (1) treated with the silane coupling agent, dried under a nitrogen atmosphere at 100 ° C. for 15 minutes, further heated at 350 ° C. for 15 minutes, gradually cooled, and cooled from the polymer (1). A non-porous resin layer (thickness: 7 μm) and a copper foil (1) were directly laminated to obtain a resin-attached metal foil.
Hereinafter, the physical properties of the obtained resin-attached metal foil were measured, and a copper-clad laminate was manufactured using the same.

(4) After embedding the resin-attached metal foil in the epoxy resin, a cross section was processed by a cross section polisher, and the cross section was observed with an SEM (Hitachi High-Tech Co., SU8230, acceleration voltage 0.7 kV). FIG. 1 shows an SEM image of the cross section. As shown in FIG. 1, it was confirmed that voids existed at the interface between the copper foil and the non-porous resin layer, and the voids existed in the concave portions of the uneven surface of the metal foil. The aspect ratio of the concave portion was 1.0 or more, and the warp ratio of the metal foil with resin was 3%. In addition, the location of the void was clearly concentrated in the concave portion.

Also, using a plasma processing apparatus (AP-1000, manufactured by NORDSON MARCH), RF output: 300 W, gap between electrodes: 2 inches, introduced gas: argon gas, introduced gas amount: 50 cm ³ / min, pressure: 13 Pa, processing Time: The non-porous resin layer side of the metal foil with resin was subjected to plasma treatment under the condition of 1 minute. Ra on the surface of the non-porous resin layer after the plasma treatment was 8 nm.

Next, on the surface of the non-porous resin layer of the metal foil with resin, an FR-4 sheet (prepared by Hitachi Chemical Co., Ltd., reinforcing fiber: glass fiber, matrix resin: epoxy resin, product name: CEA-67N 0.2 t) (HAN), thickness: 0.2 mm), and heat-pressed under vacuum (temperature: 185 ° C., pressure: 3.0 MPa, time: 60 minutes) to form a cured prepreg layer, a non-porous resin A single-sided copper-clad laminate in which the layer and the copper foil (1) were laminated in this order was obtained.
A single-sided copper-clad laminate was placed on each side of the FR-4 sheet so that a copper foil (1) was formed as the outermost layer. A press temperature: 185 ° C., a press pressure: 3.0 MPa, and a press Time: Vacuum hot pressing under the condition of 60 minutes to obtain a double-sided copper-clad laminate.
The peel strength between the copper foil (1) and the non-porous resin layer in the obtained single-sided copper-clad laminate was 14 N / cm. Swelling and warpage of the non-porous resin layer were suppressed. The electrical characteristics of the printed wiring board formed by forming a transmission circuit on the obtained double-sided copper-clad laminate were 4.5 or less in relative dielectric constant and 0.015 or less in dielectric loss tangent.
The single-sided copper-clad laminate in which no void exists at the interface between the metal foil and the non-porous resin layer retains the peel strength, but swells in a solder reflow test and has a large curl due to warpage.
In addition, the entire contents of the specification, claims, abstract and drawings of Japanese Patent Application No. 2018-122106 filed on June 27, 2018 are cited herein, and the disclosure of the specification of the present invention is as follows. Incorporate.

Claims

A metal foil having an uneven surface, and a non-porous resin layer containing a tetrafluoroethylene-based polymer in contact with the uneven surface of the metal foil, a part of the interface between the metal foil and the non-porous resin layer Metal foil with resin, which has voids.
樹脂 The resin-attached metal foil according to claim 1, wherein the void exists in a concave portion of the uneven surface of the metal foil.
The resin-coated metal foil according to claim 1 or 2, wherein the resin-coated metal foil has a warpage of 5% or less.
The metal foil with resin according to any one of claims 1 to 3, wherein the peel strength between the metal foil and the non-porous resin layer is 5 N / cm or more.
The thickness of the metal foil is 5 to 25 μm, the thickness of the non-porous resin layer is 0.05 to 100 μm, and the ratio of the thickness of the non-porous resin layer to the thickness of the metal foil is The metal foil with resin according to any one of claims 1 to 4, which is 0.01 to 10.0.
The metal foil with resin according to any one of claims 1 to 5, wherein the ten-point average roughness of the uneven surface of the metal foil is 0.2 to 4 μm.
7. The tetrafluoroethylene-based polymer having a temperature range exhibiting a storage elastic modulus of 0.1 to 5.0 MPa at 260 ° C. or lower and a melting point exceeding 260 ° C. The metal foil with resin according to any one of the above.
The tetrafluoroethylene-based polymer is a polymer including a unit based on tetrafluoroethylene and a unit based on at least one monomer selected from the group consisting of perfluoro (alkyl vinyl ether), hexafluoropropylene and fluoroalkylethylene. The metal foil with resin according to any one of claims 1 to 7.
9. The polymer according to claim 1, wherein the tetrafluoroethylene-based polymer is a polymer having at least one functional group selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group, an amide group, an amino group, and an isocyanate group. The metal foil with resin according to any one of the above.
(10) A method for manufacturing a printed wiring board, wherein a transmission circuit is formed by etching the metal foil of the resin-attached metal foil according to any one of (1) to (9) to obtain a printed wiring board.