Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42

Definitions

• JP 2023-000377 A describes a laminate in which a coating film containing a powder of a high melting point adhesive resin is laminated on at least one surface of a substrate film made of polyether ether ketone (PEEK) resin.
• PEEK polyether ether ketone
• WO 2022/163776 describes a polymer film having a layer A and a layer B on at least one surface of the layer A, the layer A containing a polymer having a dielectric tangent of 0.01 or less, the layer B containing an additive, and the layer B having an inflection point in the change in elastic modulus with temperature change or deformation speed change, or the elastic modulus decreases under pressure.
• a copper-clad laminate is manufactured by laminating a copper foil on the surface of a polymer film.
• a wiring board is manufactured by stacking a copper-clad laminate and a wiring substrate so that the polymer film of the copper-clad laminate and the wiring substrate are in contact with each other.
• the polymer film deforms to conform to the steps formed on the surface of the wiring substrate from the viewpoint of adhesion.
• a polymer film having excellent step conformability to a wiring substrate is used for a copper-clad laminate, delamination may occur during the reflow soldering process performed when mounting electronic components. For this reason, there has been a demand for a material that has both step conformability to a wiring substrate and excellent adhesion during reflow soldering (i.e., excellent heat resistance).
• the problem that one embodiment of the present disclosure aims to solve is to provide a polymer film, a laminate, and a method for manufacturing a laminate that are excellent in step conformability and heat resistance.
• Means for solving the above problems include the following aspects. ⁇ 1> A step of disposing a metal substrate on at least one surface of a polymer film including a layer B having a dielectric loss tangent of 0.01 or less and including a material a and a material b having different transition temperatures, and having an elastic modulus of 0.60 MPa or less at 160°C; A step of pressing at a temperature at which the elastic modulus of each of material a and material b is 0.60 MPa or more; a step of heating the material a to a temperature at which the elastic modulus of the material a is less than 0.60 MPa and the elastic modulus of the material b is 0.60 MPa or more, at a pressure where the absolute value of the pressure change rate from the pressure in the pressurizing step is 10% or less; A step of cooling the material a to a temperature at which the elastic modulus of the material a is 0.60 MPa or more; and removing the load, in this order.
• ⁇ 2> The method for producing a laminate according to ⁇ 1>, wherein the pressure in the heating step is 2 MPa to 6 MPa.
• ⁇ 3> The method for producing a laminate according to ⁇ 1> or ⁇ 2>, wherein the heating step is performed at a temperature of 170° C. to 260° C.
• the polymer film further comprises a layer A having an elastic modulus of greater than 0.60 MPa at 160° C.;
• ⁇ 7> The method for producing a laminate according to any one of ⁇ 1> to ⁇ 6>, wherein the material a is at least one selected from the group consisting of a styrene-ethylene-butylene-styrene block copolymer, a styrene-isobutylene-styrene block copolymer, a styrene-ethylene-propylene-styrene copolymer, a styrene-isoprene-styrene block copolymer, and hydrogenated products thereof.
• the material a is at least one selected from the group consisting of a styrene-ethylene-butylene-styrene block copolymer, a styrene-isobutylene-styrene block copolymer, a styrene-ethylene-propylene-styrene copolymer, a styrene
• ⁇ 8> The method for producing a laminate according to any one of ⁇ 1> to ⁇ 7>, wherein the material b is at least one selected from the group consisting of a liquid crystal polymer, a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, and a fluororesin.
• the content of the material b is 10 mass % to 30 mass % based on the total mass of the layer B.
• the layer A has a surface roughness Rc of more than 5 ⁇ m on the side on which the layer B is disposed
• the layer B includes a material a having an elastic modulus of less than 0.10 MPa at 260° C. and a material b having an elastic modulus of 0.10 MPa or more at 260° C., and has an elastic modulus of 0.60 MPa or less at 160° C.;
• ⁇ 12> The polymer film according to ⁇ 10> or ⁇ 11>, wherein the material a is an elastomer containing a structural unit derived from styrene.
• the material a is at least one selected from the group consisting of a styrene-ethylene-butylene-styrene block copolymer, a styrene-isobutylene-styrene block copolymer, a styrene-ethylene-propylene-styrene copolymer, a styrene-isoprene-styrene block copolymer, and hydrogenated products thereof.
• the material b is at least one selected from the group consisting of a liquid crystal polymer, a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, and a fluororesin.
• a liquid crystal polymer a polymer of a compound having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond
• a fluororesin ⁇ 15>
• a laminate comprising the polymer film according to any one of ⁇ 10> to ⁇ 14> and a metal layer or metal wiring disposed on at least one surface of the polymer film.
• the semiconductor device includes, in this order, a layer A, a layer B, and a metal layer or metal wiring, The laminate according to ⁇ 15>, wherein a peel strength between the Layer B and the metal layer or the metal wiring is 0.3 kN/m or more.
• a polymer film, a laminate, and a method for manufacturing a laminate that have excellent step conformability and heat resistance are provided.
• the use of "to" indicating a range of values means that the values before and after it are included as the lower limit and upper limit.
• the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages.
• the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
• an "alkyl group” includes not only an alkyl group that has no substituent (an unsubstituted alkyl group) but also an alkyl group that has a substituent (a substituted alkyl group).
• (meth)acrylic is a term used as a concept including both acrylic and methacrylic
• (meth)acryloyl is a term used as a concept including both acryloyl and methacryloyl.
• the term "process" in this specification includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Furthermore, in the present disclosure, combinations of two or more preferred aspects are more preferred aspects.
• GPC gel permeation chromatography
• the average particle size (e.g., D50) of the particles in this disclosure is measured using a laser diffraction/scattering type particle size distribution analyzer.
• a laser diffraction/scattering type particle size distribution analyzer For example, HORIBA's LA-950V2 is used as the laser diffraction/scattering type particle size distribution analyzer.
• the method for producing a laminate according to the present disclosure includes, in this order, a step of arranging a metal substrate on at least one surface of a polymer film that includes material a and material b having different transition temperatures, layer B having an elastic modulus of 0.60 MPa or less at 160° C., and a dielectric dissipation factor of 0.01 or less (hereinafter also referred to as a “metal substrate arranging step”), a step of applying pressure at a temperature at which the elastic moduli of material a and material b are each 0.60 MPa or more (hereinafter also referred to as a “pressuring step”), a step of heating to a temperature at which the elastic modulus of material a is less than 0.60 MPa and the elastic modulus of material b is 0.60 MPa or more at a pressure where the absolute value of the pressure change rate from the pressure in the pressing step is 10% or less (hereinafter also referred to as a “heating step”), a step of cooling
• thermocompression bonding When manufacturing a multi-layer copper-clad laminate, the copper foil and the polymer film are laminated and then subjected to thermocompression bonding, during which heating causes some of the materials contained in the polymer film to become fluid.
• thermocompression bonding if the surface of the polymer film is not covered and heated in contact with a substance with low surface energy such as air, or heated without pressure, some of the materials that tend to flow easily may move in the polymer film, and the materials that tend to flow after bonding may aggregate.
• a phenomenon of movement or aggregation was prominent in a polymer film with a low elastic modulus of 0.60 MPa or less at 160°C and excellent step-following ability against the wiring substrate.
• the film In the reflow soldering process performed when mounting electronic components, the film is heated at a high temperature (e.g., 260°C), and at that time, the water present in the polymer film becomes supersaturated and diffuses, and it is thought that bubble nuclei are generated in the aggregated parts of the materials that tend to flow. Conventionally, the growth and foaming of bubble nuclei may cause peeling between the polymer film and the metal layer, or cohesive failure may occur within the polymer film.
• a high temperature e.g., 260°C
• the metal base arrangement step, the pressurizing step, the heating step, the cooling step, and the unloading step are included in this order, so that the movement of the material contained in the polymer film is suppressed, and it is preferable that the pressurizing step is performed in a degassed state. It is considered that the generation and growth of bubble nuclei are suppressed in the reflow soldering step without aggregation of the material that is easy to flow, and as a result, peeling between the polymer film and the metal layer is suppressed. In other words, it has excellent heat resistance.
• JP 2023-000377 A and WO 2022/163776 do not mention the metal substrate placement process, the pressurization process, the heating process, the cooling process, and the unloading process being carried out in this order.
• the metal substrate disposing step includes disposing at least one of a polymer film including a layer B having a modulus of elasticity of 0.60 MPa or less at 160° C. and a dielectric loss tangent of 0.01 or less, the layer B including a material a and a material b having different transition temperatures. A metal substrate is placed on one surface.
• Layer B includes material a and material b having different transition temperatures.
• the difference in transition temperatures between material a and material b can be confirmed by a differential scanning calorimeter.
• the transition temperature may be a phase transition temperature or a glass transition temperature.
• the material a may be a low molecular weight compound or a high molecular weight compound.
• the elastic modulus of the material a at 260° C. is preferably less than 0.10 MPa, and more preferably 0.05 MPa or less.
• the lower limit of the elastic modulus of the material a at 260° C. is not particularly limited, and is, for example, 0.001 MPa.
• thermoplastic elastomers examples include elastomers containing structural units derived from styrene (polystyrene-based elastomers), polyester-based elastomers, polyolefin-based elastomers, polyurethane-based elastomers, polyamide-based elastomers, polyacrylic-based elastomers, silicone-based elastomers, polyimide-based elastomers, etc.
• the thermoplastic elastomer may be a hydrogenated product.
• the content of material a is preferably 40% by mass to 95% by mass, and more preferably 60% by mass to 90% by mass, relative to the total mass of layer B.
• the material a is preferably used as a powder in the production of the polymer film. More preferably, the method of converting the material a into a powder includes a swelling step of swelling the material a with a liquid medium, and a grinding step of grinding the swollen material A.
• the material b may be a low molecular weight compound or a high molecular weight compound.
• the elastic modulus of material b is preferably 0.10 MPa or more, and more preferably 1.0 MPa or more, at 260° C.
• the upper limit of the elastic modulus of material b at 260° C. is not particularly limited, and is, for example, 1000 MPa.
• the elastic modulus of material b at 260° C. is measured by the following method.
• a film cross-section sample was prepared by obliquely cutting with a microtome so that the cross-section had a thickness of 50 ⁇ m.
• the 260°C elastic modulus of the portion of material b is measured as the indentation elastic modulus using a nanoindentation method.
• the indentation elastic modulus is measured by applying a load with a Vickers indenter at a loading rate of 0.28 mN/sec using a microhardness tester (for example, product name "DUH-W201" manufactured by Shimadzu Corporation), holding the maximum load of 10 mN for 10 seconds, and then unloading at a loading rate of 0.28 mN/sec.
• a microhardness tester for example, product name "DUH-W201" manufactured by Shimadzu Corporation
• Examples of material b include liquid crystal polymers, fluororesins, polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, polyphenylene ether and its modified products, aromatic polyether ketone, phenolic resins, epoxy resins, polyimides, cyanate resins, bismaleimide resins, and thermosetting resins such as triazine resins.
• material b contains a liquid crystal polymer.
• the type of liquid crystal polymer is not particularly limited, and any known liquid crystal polymer can be used.
• the liquid crystal polymer may be a thermotropic liquid crystal polymer that exhibits liquid crystallinity in a molten state, or a lyotropic liquid crystal polymer that exhibits liquid crystallinity in a solution state. In the case of a thermotropic liquid crystal, it is preferable that the liquid crystal polymer melts at a temperature of 450° C. or less.
• liquid crystal polymers examples include liquid crystal polyester, liquid crystal polyester amide in which an amide bond has been introduced into liquid crystal polyester, liquid crystal polyester ether in which an ether bond has been introduced into liquid crystal polyester, and liquid crystal polyester carbonate in which a carbonate bond has been introduced into liquid crystal polyester.
• the liquid crystal polymer is preferably a polymer having an aromatic ring, and is more preferably an aromatic polyester or an aromatic polyester amide.
• the liquid crystal polymer may be a polymer in which an isocyanate-derived bond such as an imide bond, a carbodiimide bond, or an isocyanurate bond has been introduced into an aromatic polyester or an aromatic polyester amide.
• an isocyanate-derived bond such as an imide bond, a carbodiimide bond, or an isocyanurate bond has been introduced into an aromatic polyester or an aromatic polyester amide.
• liquid crystal polymer is preferably a fully aromatic liquid crystal polymer made using only aromatic compounds as raw material monomers.
• the melting point of the liquid crystal polymer is preferably greater than 260°C, more preferably greater than 260°C and less than 350°C, and even more preferably greater than 260°C and less than 330°C.
• the melting point is measured using a differential scanning calorimeter.
• a differential scanning calorimeter For example, it is measured using a product called "DSC-60A Plus" (manufactured by Shimadzu Corporation).
• the heating rate in the measurement is 10°C/min.
• the weight average molecular weight of the liquid crystal polymer is preferably 1,000,000 or less, more preferably 3,000 to 300,000, even more preferably 5,000 to 100,000, and particularly preferably 5,000 to 30,000.
• the liquid crystal polymer preferably contains an aromatic polyesteramide from the viewpoint of further reducing the dielectric tangent.
• An aromatic polyesteramide is a resin having at least one aromatic ring and having an ester bond and an amide bond.
• the aromatic polyesteramide is preferably a fully aromatic polyesteramide.
• the aromatic polyester amide is preferably a crystalline polymer.
• the material b preferably contains a crystalline aromatic polyester amide.
• the dielectric loss tangent is further reduced.
• crystalline polymer refers to a polymer that has a clear endothermic peak, not a stepwise change in endothermic amount, in differential scanning calorimetry (DSC). Specifically, for example, it means that the half-width of the endothermic peak is within 10° C. when measured at a heating rate of 10° C./min. Polymers with a half-width exceeding 10° C. and polymers without a clear endothermic peak are classified as amorphous polymers and are distinguished from crystalline polymers.
• the aromatic polyester amide preferably contains a constitutional unit represented by the following formula 1, a constitutional unit represented by the following formula 2, and a constitutional unit represented by the following formula 3. -O-Ar 1 -CO- ... Formula 1 -CO-Ar 2 -CO-...Formula 2 —NH—Ar 3 —O— Formula 3
• Ar 1 , Ar 2 and Ar 3 each independently represent a phenylene group, a naphthylene group or a biphenylylene group.
• the structural unit represented by formula 1 will also be referred to as "unit 1", etc.
• the unit 1 can be introduced, for example, by using an aromatic hydroxycarboxylic acid as a raw material.
• the unit 2 can be introduced, for example, by using an aromatic dicarboxylic acid as a raw material.
• Unit 3 can be introduced, for example, by using an aromatic hydroxylamine as a raw material.
• aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, and aromatic hydroxylamine may each be independently replaced with a derivative capable of polycondensation.
• aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid esters and aromatic dicarboxylic acid esters by converting the carboxy group to an alkoxycarbonyl group or an aryloxycarbonyl group.
• Aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid halides and aromatic dicarboxylic acid halides by converting the carboxy groups to haloformyl groups.
• Aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids can be replaced with aromatic hydroxycarboxylic acid anhydrides and aromatic dicarboxylic acid anhydrides by converting the carboxy groups to acyloxycarbonyl groups.
• polycondensable derivatives of compounds having a hydroxy group such as aromatic hydroxycarboxylic acids and aromatic hydroxyamines
• examples of polycondensable derivatives of compounds having a hydroxy group include those obtained by acylation of a hydroxy group into an acyloxy group (acylated products).
• aromatic hydroxycarboxylic acids and aromatic hydroxylamines can be replaced with their acylated counterparts by acylation of the hydroxy group to convert it to an acyloxy group.
• polycondensable derivatives of aromatic hydroxylamines include those obtained by acylation of the amino group to an acylamino group (acylated product).
• aromatic hydroxyamines can be replaced with acylated products by acylation of the amino group to convert them to acylamino groups.
• Ar 1 is preferably a p-phenylene group, a 2,6-naphthylene group, or a 4,4'-biphenylylene group, and more preferably a 2,6-naphthylene group.
• unit 1 is, for example, a constitutional unit derived from p-hydroxybenzoic acid.
• unit 1 is, for example, a constitutional unit derived from 6-hydroxy-2-naphthoic acid.
• Ar 1 is a 4,4'-biphenylylene group
• unit 1 is, for example, a constitutional unit derived from 4'-hydroxy-4-biphenylcarboxylic acid.
• Ar 2 is preferably a p-phenylene group, an m-phenylene group, or a 2,6-naphthylene group, and more preferably an m-phenylene group.
• unit 2 is, for example, a constitutional unit derived from terephthalic acid.
• unit 2 is, for example, a constitutional unit derived from isophthalic acid.
• Ar 2 is a 2,6-naphthylene group
• unit 2 is, for example, a constitutional unit derived from 2,6-naphthalenedicarboxylic acid.
• Ar 3 is preferably a p-phenylene group or a 4,4′-biphenylylene group, and more preferably a p-phenylene group.
• unit 3 is, for example, a constitutional unit derived from p-aminophenol.
• unit 3 is, for example, a constitutional unit derived from 4-amino-4'-hydroxybiphenyl.
• the content of units 1 is preferably 30 mol % or more, the content of units 2 is preferably 35 mol % or less, and the content of units 3 is preferably 35 mol % or less.
• the content of unit 1 is more preferably 30 mol % to 80 mol %, further preferably 30 mol % to 60 mol %, and particularly preferably 30 mol % to 40 mol %, based on the total content of unit 1, unit 2, and unit 3.
• the content of unit 2 is preferably 10 mol % to 35 mol %, more preferably 20 mol % to 35 mol %, and particularly preferably 30 mol % to 35 mol %, based on the total content of unit 1, unit 2, and unit 3.
• the content of unit 3 is preferably 10 mol % to 35 mol %, more preferably 20 mol % to 35 mol %, and particularly preferably 30 mol % to 35 mol %, based on the total content of unit 1, unit 2, and unit 3.
• the total content of each structural unit is the sum of the amounts (moles) of each structural unit, which is calculated by dividing the mass of each structural unit constituting the aromatic polyesteramide by the formula weight of the structural unit.
• the ratio of the content of unit 2 to the content of unit 3, expressed as [content of unit 2]/[content of unit 3] (mol/mol), is preferably 0.9/1 to 1/0.9, more preferably 0.95/1 to 1/0.95, and even more preferably 0.98/1 to 1/0.98.
• the aromatic polyesteramide may have two or more types of units 1 to 3, each of which is independent.
• the aromatic polyesteramide may also have other structural units in addition to units 1 to 3.
• the content of the other structural units is preferably 10 mol % or less, more preferably 5 mol % or less, based on the total content of all structural units.
• Aromatic polyesteramides are preferably produced by melt polymerizing raw material monomers that correspond to the structural units that make up the aromatic polyesteramide.
• the weight average molecular weight of the aromatic polyester amide is preferably 1,000,000 or less, more preferably 3,000 to 300,000, even more preferably 5,000 to 100,000, and particularly preferably 5,000 to 30,000.
• -Fluorine resin- Material b may be a fluororesin from the viewpoints of heat resistance and mechanical strength.
• the type of fluororesin is not particularly limited, and any known fluororesin can be used.
• Fluororesins include homopolymers and copolymers that contain structural units derived from fluorinated ⁇ -olefin monomers, i.e., ⁇ -olefin monomers that contain at least one fluorine atom. Fluororesins also include copolymers that contain structural units derived from fluorinated ⁇ -olefin monomers and structural units derived from non-fluorinated ethylenically unsaturated monomers that are reactive with fluorinated ⁇ -olefin monomers.
• Fluorinated ⁇ -olefin monomers include CF 2 ⁇ CF 2 , CHF ⁇ CF 2 , CH 2 ⁇ CF 2 , CHCl ⁇ CHF, CCIF ⁇ CF 2 , CCl 2 ⁇ CF 2 , CCIF ⁇ CCIF, CHF ⁇ CCl 2 , CH 2 ⁇ CCIF , CCl 2 ⁇ CCIF, CF 3 CF ⁇ CF 2 , CF 3 CF ⁇ CHF , CF 3 CH ⁇ CF 2 , CF 3 CH ⁇ CH 2 , CHF 2 CH ⁇ CHF, CF 3 CF ⁇ CF 2 , and perfluoro ( alkyl having 2 to 8 carbon atoms)vinyl ethers (e.g., perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and perfluorooctyl vinyl ether).
• perfluoro ( alkyl having 2 to 8 carbon atoms)vinyl ethers e.g., perfluoromethyl vinyl ether
• the fluorinated ⁇ -olefin monomer is preferably at least one monomer selected from the group consisting of tetrafluoroethylene (CF 2 ⁇ CF 2 ), chlorotrifluoroethylene (CCIF ⁇ CF 2 ), (perfluorobutyl)ethylene, vinylidene fluoride (CH 2 ⁇ CF 2 ), and hexafluoropropylene (CF 2 ⁇ CFCF 3 ).
• Non-fluorinated ethylenically unsaturated monomers include ethylene, propylene, butene, ethylenically unsaturated aromatic monomers (eg, styrene and ⁇ -methylstyrene), and the like.
• the fluorinated ⁇ -olefin monomers may be used alone or in combination of two or more kinds.
• the non-fluorinated ethylenically unsaturated monomers may be used alone or in combination of two or more kinds.
• fluororesins include polychlorotrifluoroethylene (PCTFE), poly(chlorotrifluoroethylene-propylene), poly(ethylene-tetrafluoroethylene) (ETFE), poly(ethylene-chlorotrifluoroethylene) (ECTFE), poly(hexafluoropropylene), poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-ethylene-propylene), poly(tetrafluoroethylene-hexafluoropropylene) (FEP), poly(tetrafluoroethylene-propylene) (FEPM), poly(tetrafluoroethylene-perfluoropropylene vinyl ether), poly(tetrafluoroethylene-perfluoroalkyl vinyl ether) (PFA) (e.g., poly(tetrafluoroethylene-perfluoropropyl vinyl ether)), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), poly((
• the aromatic polyether ketone is preferably polyether ether ketone.
• the layer B may contain other additives in addition to the material a and the material b.
• known additives can be used, such as a curing agent, a leveling agent, a defoaming agent, an antioxidant, an ultraviolet absorbing agent, a flame retardant, and a colorant.
• inorganic foaming agents examples include bicarbonates such as sodium bicarbonate; carbonates; and combinations of bicarbonates and organic acid salts such as sodium citrate.
• Layer A may contain only one type of polymer with a dielectric tangent of 0.01 or less, or may contain two or more types.
• the dielectric tangent of a polymer having a dielectric tangent of 0.01 or less is preferably 0.005 or less, and more preferably greater than 0 and less than 0.003, from the viewpoint of the dielectric tangent of the polymer film.
• polymers with a dielectric tangent of 0.01 or less include liquid crystal polymers, fluororesins, polymers of compounds having a cyclic aliphatic hydrocarbon group and a group having an ethylenically unsaturated bond, thermoplastic resins such as polyether ether ketone, polyolefin, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and modified products thereof, and polyether imide; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenol resins, epoxy resins, polyimides, and cyanate resins.
• thermoplastic resins such as polyether ether ketone, polyolefin, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and modified products thereof, and polyether
• the filler may be particulate or fibrous, and may be inorganic or organic particles. Specific examples of inorganic and organic particles are as described above.
• Layer A may contain additives other than the above-mentioned components. Preferred embodiments of the other additives that may be contained in Layer A are the same as preferred embodiments of the other additives that may be contained in Layer B.
• the layer A may contain, as other additives, resins other than the polymer having a dielectric loss tangent of 0.01 or less.
• resins other than polymers having a dielectric tangent of 0.01 or less include thermoplastic resins other than liquid crystal polyesters, such as polypropylene, polyamide, polyesters other than liquid crystal polyesters, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and modified products thereof, and polyether imide; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenol resins, epoxy resins, polyimide resins, and cyanate resins.
• the total content of other additives in Layer A is preferably 25 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the polymer having a dielectric tangent of 0.01 or less.
• the elastic modulus of layer A at 160° C. is preferably more than 0.60 MPa, and more preferably 10 MPa or more.
• layer A can support layer B and has excellent step conformability.
• the upper limit of the elastic modulus of layer A at 160° C. is not particularly limited, but is 1000 MPa from the viewpoint of suppressing wiring distortion and the like.
• the elastic modulus of Layer A at 160° C. is measured by the following method.
• a film cross-section sample was prepared by obliquely cutting with a microtome so that the cross-section had a thickness of 50 ⁇ m.
• the elastic modulus of layer A is measured as the indentation elastic modulus using a nanoindentation method.
• the indentation elastic modulus is measured by applying a load at a loading rate of 0.28 mN/sec with a Vickers indenter using a microhardness tester (for example, product name "DUH-W201" manufactured by Shimadzu Corporation), holding the maximum load of 10 mN for 10 seconds, and then unloading at a loading rate of 0.28 mN/sec.
• the cross-sectional sample is measured at 20 arbitrary positions at 160°C, and the average value is taken as the elastic modulus.
• the average thickness of layer A is not particularly limited, but from the viewpoint of the dielectric tangent, heat resistance, and suppression of wiring distortion of the laminate, it is preferably 5 ⁇ m to 90 ⁇ m, more preferably 10 ⁇ m to 70 ⁇ m, and particularly preferably 15 ⁇ m to 50 ⁇ m.
• the polymer film preferably further comprises layer C in addition to layer A and layer B, and more preferably comprises layer B, layer A, and layer C in this order.
• Layer C is preferably an adhesive layer, i.e., Layer C is preferably a surface layer (outermost layer).
• layer C contains at least one type of polymer.
• the preferred embodiment of the polymer used in layer C is the same as the preferred embodiment of the polymer used in layer A having a dielectric tangent of 0.01 or less.
• the polymer contained in layer C may be the same as or different from the polymer contained in layer A or layer B, but from the viewpoint of adhesion between layer A and layer C, it is preferable that the polymer is the same as the polymer contained in layer A.
• layer C contains an epoxy resin to bond the metal layer to layer A.
• the epoxy resin is preferably a crosslinked product of a multifunctional epoxy compound.
• a multifunctional epoxy compound is a compound having two or more epoxy groups.
• the number of epoxy groups in a multifunctional epoxy compound is preferably 2 to 4.
• layer C contains an aromatic polyester amide and an epoxy resin.
• the layer C may contain a filler.
• the preferred embodiments of the filler used in Layer C are the same as those of the filler used in Layer A.
• Layer C may contain additives other than those mentioned above. Preferred embodiments of the other additives used in Layer C are the same as those of the other additives used in Layer A, except as described below.
• the average thickness of layer C is preferably thinner than the average thickness of layer A from the viewpoints of the dielectric tangent of the laminate and adhesion to metals.
• T A /T C which is the ratio of the average thickness T A of Layer A to the average thickness T C of Layer C, is preferably greater than 1, more preferably from 2 to 100, even more preferably from 2.5 to 20, and particularly preferably from 3 to 10, from the viewpoints of the dielectric tangent of the laminate and the adhesion to the metal layer.
• T B /T C which is the ratio of the average thickness T B of Layer B to the average thickness T C of Layer C, is preferably greater than 1, more preferably from 2 to 100, even more preferably from 2.5 to 20, and particularly preferably from 3 to 10, from the viewpoints of the dielectric tangent of the laminate and the adhesion to the metal layer.
• the average thickness of layer C is preferably 0.1 ⁇ m to 20 ⁇ m, more preferably 0.5 ⁇ m to 15 ⁇ m, even more preferably 1 ⁇ m to 10 ⁇ m, and particularly preferably 2 ⁇ m to 8 ⁇ m.
• the method for measuring the average thickness of each layer in a polymer film is as follows:
• the polymer film is cut on a plane perpendicular to the surface of the polymer film, the thickness is measured at five or more points on the cross section, and the average of these measurements is taken as the average thickness.
• the polymer film has a dielectric loss tangent of 0.01 or less, preferably 0.005 or less, and more preferably 0.003 or less.
• the lower limit of the dielectric loss tangent is not particularly limited, but is, for example, 0.0005.
• the dielectric loss tangent is measured by the following method.
• the dielectric loss tangent is measured by a resonance perturbation method at a frequency of 10 GHz.
• a 10 GHz cavity resonator (Kanto Electronics Application Development Co., Ltd.'s "CP531") is connected to a network analyzer (Agilent Technology's "E8363B”), a polymer film is inserted into the cavity resonator, and the dielectric loss tangent is measured from the change in resonance frequency before and after insertion for 96 hours under an environment of 25°C temperature and 60% RH.
• the average thickness of the polymer film is not particularly limited, but from the viewpoint of dielectric tangent and step conformability, it is preferably 5 ⁇ m to 90 ⁇ m, more preferably 10 ⁇ m to 70 ⁇ m, and particularly preferably 15 ⁇ m to 50 ⁇ m.
• the average thickness of the polymer film is measured at any five points using an adhesive film thickness meter, such as an electronic micrometer (product name "KG3001A", manufactured by Anritsu Corporation), and the average value is calculated.
• an adhesive film thickness meter such as an electronic micrometer (product name "KG3001A", manufactured by Anritsu Corporation)
• the method for producing a laminate according to the present disclosure preferably further includes a step of producing a polymer film including layer A and layer B disposed on at least one surface of layer A (hereinafter also referred to as a "polymer film production step").
• the polymer film may also include layer C.
• Suitable film-forming methods include, for example, co-casting, multi-layer coating, and co-extrusion. Among these, the co-casting method is preferred.
• the diameter of the beads used in the bead mill is preferably larger than the average particle diameter of the particles used in preparing the solution for forming layer A.
• the diameter of the beads is, for example, 0.1 mm to 5 mm.
• organic solvent examples include carbonates such as propylene carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, and urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphoramide and tri-n-butylphosphoric acid, and two or more of these may be used.
• carbonates such as propylene carbonate and propylene carbonate
• amines such as triethylamine
• nitrogen-containing heterocyclic aromatic compounds such as pyridine
• nitriles such as acetonitrile and succinon
• the solvent is preferably a solvent mainly composed of an aprotic compound, particularly an aprotic compound without halogen atoms, because it is less corrosive and easier to handle, and the proportion of the aprotic compound in the entire solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and particularly preferably 90% by mass to 100% by mass.
• amides such as N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, and N-methylpyrrolidone, or esters such as ⁇ -butyrolactone, because they easily dissolve liquid crystal polymers, and N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone are more preferable.
• a solvent mainly composed of a compound having a dipole moment of 3 to 5 is preferred because it easily dissolves the liquid crystal polymer, and the proportion of the compound having a dipole moment of 3 to 5 in the entire solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and particularly preferably 90% by mass to 100% by mass.
• the aprotic compound it is preferable to use a compound having a dipole moment of 3 to 5.
• the solvent is preferably a solvent mainly composed of a compound having a boiling point of 220° C. or lower at 1 atmospheric pressure, because it is easy to remove.
• the proportion of the compound having a boiling point of 220° C. or lower at 1 atmospheric pressure in the entire solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and particularly preferably 90% by mass to 100% by mass.
• the aprotic compound it is preferable to use a compound having a boiling point of 220° C. or lower at 1 atmospheric pressure.
• a support in the manufacturing process of the polymer film, when manufacturing by the above-mentioned co-casting method, multi-layer coating method, co-extrusion method, etc., a support may be used.
• the support examples include a metal drum, a metal band, a glass plate, a resin film, and a metal foil.
• the support is preferably a metal drum, a metal band, or a resin film.
• the support may have a surface treatment layer formed on its surface so that it can be easily peeled off.
• the surface treatment layer may be made of hard chrome plating, fluororesin, or the like.
• the average thickness of the support is not particularly limited, but is preferably from 25 to 75 ⁇ m, and more preferably from 50 to 75 ⁇ m.
• stretching In the manufacturing process of the polymer film, stretching can be appropriately combined from the viewpoint of controlling molecular orientation and adjusting the thermal expansion coefficient and mechanical properties.
• the stretching method is not particularly limited, and known methods can be referred to. It may be performed in a state containing a solvent or in a dry film state. Stretching in a state containing a solvent may be performed by gripping and stretching the laminate, or may be performed by utilizing autogenous shrinkage due to drying without stretching. Stretching is particularly effective for the purpose of improving the breaking elongation and breaking strength when the brittleness of the film is reduced by the addition of inorganic fillers, etc.
• the metal substrate used in the metal substrate arranging step is, for example, a rolled metal foil formed by a rolling method, or an electrolytic metal foil formed by an electrolytic method.
• the metal substrate may be made of a conventionally known material, and is preferably made of silver or copper, and more preferably made of copper.
• the metal substrates may be disposed on both sides of the polymer film.
• the two metal substrates may be metal substrates of the same material, thickness and shape, or metal substrates of different materials, thicknesses and shapes. From the viewpoint of characteristic impedance adjustment, the two metal substrates may be metal substrates of different materials and thicknesses.
• the average thickness of the metal substrate is not particularly limited, but is preferably 2 ⁇ m to 20 ⁇ m, more preferably 3 ⁇ m to 18 ⁇ m, and even more preferably 5 ⁇ m to 12 ⁇ m.
• the pressurizing step is a step of applying pressure to at least one surface of the polymer film with a metal substrate disposed thereon at a temperature at which the elastic modulus of each of materials a and b is 0.60 MPa or more.
• the pressurizing step is preferably performed in a degassed state in advance so that air is mixed into the laminate and the movement or aggregation of some of the materials that tend to flow is suppressed.
• the temperature at which the elastic modulus of material a and material b is 0.60 MPa or more is, for example, -10°C to 150°C.
• the elastic modulus of material a and material b is 0.60 MPa or more, and preferably 1.0 MPa or more.
• the upper limit of the elastic modulus of material a and material b in the pressurizing process is not particularly limited, and is, for example, 100 MPa.
• the pressure in the pressurizing step is preferably 1 MPa to 15 MPa, more preferably 2 MPa to 10 MPa, and even more preferably 2 MPa to 6 MPa.
• the holding time at the temperature at which the elastic modulus of material a and material b is 0.60 MPa or more is, for example, 0.001 to 10 minutes.
• the method of applying pressure in the pressure step is not particularly limited, and may be performed using a laminator, for example.
• the heating step is a step of heating to a temperature at which the elastic modulus of material a is less than 0.60 MPa and the elastic modulus of material b is 0.60 MPa or more, at a pressure where the absolute value of the pressure change rate from the pressure in the pressurizing step is 10% or less.
• the absolute value of the rate of change in pressure from the pressure in the pressurizing step is 10% or less
• Pressure change rate (%) ⁇ (pressure in pressurizing step) ⁇ (pressure in heating step)/(pressure in pressurizing step) ⁇ 100
• the pressure in the heating step is preferably 1 MPa to 15 MPa, more preferably 2 MPa to 10 MPa, and even more preferably 2 MPa to 6 MPa.
• the temperature at which the elastic modulus of material a is less than 0.60 MPa and the elastic modulus of material b is 0.60 MPa or more is, for example, 160°C to 260°C, and from the viewpoint of suppressing the flow of material a, 170°C to 260°C is preferable.
• the elastic modulus of material a is less than 0.60 MPa, and preferably 0.30 MPa or less. There is no particular limit to the lower limit of the elastic modulus of material a in the heating process, and it is, for example, 0.01 MPa.
• the elastic modulus of material b is 0.60 MPa or more, and preferably 1.0 MPa or more. There is no particular upper limit to the elastic modulus of material b in the heating process, and it is, for example, 1000 MPa.
• the holding time at the temperature at which the elastic modulus of material a is less than 0.60 MPa and the elastic modulus of material b is 0.60 MPa or more is, for example, 1 minute to 200 minutes.
• the cooling step is a step of cooling the material a to a temperature at which the elastic modulus of the material a is 0.60 MPa or more.
• the temperature at which the elastic modulus of material a is 0.60 MPa or more is, for example, -10°C to 150°C.
• the elastic modulus of material a after cooling is 0.60 MPa or more, and preferably 1.0 MPa or more. There is no particular upper limit to the elastic modulus of material a after cooling, and it is, for example, 1000 MPa.
• the cooling method used in the cooling process is not particularly limited, and examples include air cooling, water cooling, etc.
• the pressure in the cooling process is preferably 1 MPa to 15 MPa, more preferably 2 MPa to 10 MPa, and even more preferably 2 MPa to 6 MPa.
• the unloading step is a step of releasing the pressure applied to at least one surface of the polymer film with the metal substrate disposed thereon, specifically, a step of setting the pressure to 0 MPa.
• the polymer film according to the present disclosure includes a layer A and a layer B disposed on at least one surface of the layer A, the layer A having a surface roughness Rc of more than 5 ⁇ m on the side on which the layer B is disposed, and the layer B includes a material a having an elastic modulus of less than 0.10 MPa at 260° C. and a material b having an elastic modulus of 0.10 MPa or more at 260° C., and has an elastic modulus of 0.60 MPa or less at 160° C.
• the polymer film according to the present disclosure also has a dielectric loss tangent of 0.01 or less.
• Layer A and Layer B are as described above in the manufacturing method of the laminate.
• the surface roughness Rc of layer A on the side where layer B is disposed is preferably more than 5 ⁇ m, and from the viewpoint of adhesion, is preferably 6 ⁇ m or more. Better adhesion also tends to improve heat resistance. Furthermore, from the viewpoint of improving the heat resistance of layers A and B, the surface roughness Rc is preferably 25 ⁇ m or less, and more preferably 10 ⁇ m or less.
• the polymer film according to the present disclosure can achieve both step conformability and heat resistance by applying the manufacturing method for the laminate according to the present disclosure as described above.
• layer A When layer B is disposed on one side of layer A, layer A only needs to have a surface roughness Rc of more than 5 ⁇ m on the side on which layer B is disposed, and there is no particular limitation on the surface roughness Rc of the side opposite to the side on which layer B is disposed.
• layer A When layer B is disposed on both sides of layer A, layer A has a surface roughness Rc of more than 5 ⁇ m on both sides.
• the surface roughness Rc is measured by the following method.
• a laminate of layers A and B is obliquely cut with a microtome to expose a cross section.
• the average height Rc of the interface of layer A on the layer B side is measured in accordance with JIS B0601:2013 (ISO4287:1997).
• the evaluation length is 500 ⁇ m.
• a laminate according to the present disclosure includes a polymer film according to the present disclosure and a metal layer or metal wiring disposed on at least one surface of the polymer film according to the present disclosure.
• the layer configuration of the laminate according to the present disclosure may be in the following form.
• Aspect 1 Metal Layer/Polymer Film (Layer A/Layer B)
• Aspect 2 Metal Layer/Polymer Film (Layer C/Layer A/Layer B)
• Aspect 3 Metal layer (also referred to as second metal layer)/polymer film (Layer A/Layer B)/metal layer
• Aspect 4 Metal layer (also referred to as second metal layer)/polymer film (Layer C/Layer A/Layer B)/metal layer
• the metal layer may be replaced with a metal wiring.
• the laminate according to the present disclosure preferably includes Layer B, Layer A, and a metal layer in this order. Specific examples include the above-mentioned aspects 1 and 2.
• the laminate according to the present disclosure preferably further includes a second metal layer, and includes the second metal layer, layer A, layer B, and a metal layer or metal wiring in this order.
• Specific examples include the above-mentioned aspects 3 and 4.
• the metal layer or metal wiring may be made of a conventionally known material, and is preferably made of silver or copper, and more preferably made of copper.
• Metal layers or metal wiring may be disposed on both sides of the polymer film.
• the two metal layers or metal wiring may be metal layers or metal wiring of the same material, thickness and shape, or metal layers or metal wiring of different materials, thickness and shape. From the viewpoint of characteristic impedance adjustment, the two metal layers or metal wiring may be metal layers or metal wiring of different materials and thicknesses.
• the metal layer is a rolled metal foil formed by a rolling method, or an electrolytic metal foil formed by an electrolytic method.
• the laminate according to the present disclosure includes, in this order, Layer A, Layer B, and a metal layer or metal wiring, and the peel strength between Layer B and the metal layer or metal wiring is preferably 0.3 kN/m or more, more preferably 0.5 kN/m or more, and even more preferably 0.7 kN/m to 5 kN/m.
• the peel strength between Layer B and a metal layer or metal wiring is measured by the following method.
• a peel test piece having a width of 1.0 cm is prepared from a laminate (laminate with metal) of a polymer film and a metal layer or metal wiring, and the peel test piece is fixed to a flat plate with double-sided adhesive tape.
• the strength (kN/m) is measured when the peel test piece is peeled at a rate of 50 mm/min by the 90° method in accordance with JIS C 5016 (1994).
• the average thickness of the metal layer is not particularly limited, but is preferably 2 ⁇ m to 20 ⁇ m, more preferably 3 ⁇ m to 18 ⁇ m, and even more preferably 5 ⁇ m to 12 ⁇ m.
• the copper foil may be a carrier-attached copper foil that is formed releasably on a support (carrier).
• the carrier may be a known one.
• the average thickness of the carrier is not particularly limited, but is preferably 10 ⁇ m to 100 ⁇ m, and more preferably 18 ⁇ m to 50 ⁇ m.
• the metal layer may be a metal layer having a circuit pattern. It is also preferable to process the metal layer into a desired circuit pattern, for example, by etching, to form a flexible printed circuit board. There are no particular limitations on the etching method, and any known etching method can be used.
• A1 Hydrogenated styrene-isobutylene-styrene block copolymer (product name "SIBSTAR103T-UL", manufactured by Kaneka Corporation) swollen with N-methylpyrrolidone, frozen and ground, average particle size 5.0 ⁇ m (D50)
• A2 Hydrogenated styrene-ethylene-butylene-styrene block copolymer (product name "Tuftec M1913", manufactured by Asahi Kasei Chemicals Corporation) jet milled product, average particle size 5.0 ⁇ m (D50)
• the aromatic polyesteramide P1a was heated in a nitrogen atmosphere from room temperature to 160°C over 2 hours and 20 minutes, then heated from 160°C to 180°C over 3 hours and 20 minutes, and held at 180°C for 5 hours to carry out solid-state polymerization, and then cooled.
• the aromatic polyesteramide P1b was then pulverized in a pulverizer to obtain a powdered aromatic polyesteramide P1b.
• the flow-initiation temperature of the aromatic polyesteramide P1b was 220°C.
• the aromatic polyester amide P1b was heated in a nitrogen atmosphere from room temperature to 180°C over 1 hour 25 minutes, then heated from 180°C to 255°C over 6 hours 40 minutes, and held at 255°C for 5 hours to carry out solid-state polymerization, and then cooled to obtain a powdered aromatic polyester amide P1.
• the flow initiation temperature of the aromatic polyesteramide P1 was 302° C.
• the melting point of the aromatic polyesteramide P1 was measured using a differential scanning calorimeter and found to be 311° C.
• the dielectric tangent of the aromatic polyesteramide P1 was 0.003.
• acetic anhydride (1.08 molar equivalent relative to the hydroxyl group) was further added. Under a nitrogen gas stream, the temperature was raised from room temperature to 150°C over 15 minutes while stirring, and refluxed at 150°C for 2 hours. Next, while distilling off the by-produced acetic acid and unreacted acetic anhydride, the temperature was raised from 150° C. to 310° C. over 5 hours, and the polymer was taken out and cooled to room temperature. The obtained polymer was heated from room temperature to 295° C. over 14 hours, and solid-state polymerized at 295° C. for 1 hour. After the solid-state polymerization, the mixture was cooled to room temperature over 5 hours.
• the obtained liquid crystal polyester was pulverized using a jet mill ("KJ-200" manufactured by Kurimoto Iron Works, Ltd.) to obtain liquid crystal polymer particles F1.
• the liquid crystal polymer particles F1 had a median diameter (D50) of 7 ⁇ m, a dielectric loss tangent of 0.0007, and a melting point of 334° C.
• ⁇ Copper foil> M1 Product name "CF-T9DA-SV-18", manufactured by Fukuda Metal Foil & Powder Co., Ltd., copper foil having a layer C of 3 ⁇ m in thickness formed on the treated surface with an average thickness of 18 ⁇ m by the following method - Formation of Layer C - 8 parts by mass of aromatic polyesteramide P1 was added to 92 parts by mass of N-methylpyrrolidone and stirred at 140° C. for 4 hours in a nitrogen atmosphere to obtain a solution of aromatic polyesteramide P1 (solid content concentration: 8% by mass). A solution was prepared by mixing 9.96 parts by mass of the aromatic polyesteramide P1 solution with 0.04 parts by mass of an aminophenol-type epoxy resin (product name "jER630", manufactured by Mitsubishi Chemical Corporation).
• Examples 1 to 14, Comparative Examples 1 to 5 A laminate was manufactured by the method described below.
• steps 1 to 4 in Table 3 below correspond to a pressurizing step, a heating step, a cooling step, and an unloading step, respectively.
• a solution for forming layer A and a solution for forming layer B were prepared.
• a solution for forming Layer A was prepared by Mixing Method A or Mixing Method B.
• (1) Mixing Method A The polymers and fillers shown in Table 1 were mixed in the contents (mass%) shown in Table 1, N-methylpyrrolidone was added to adjust the solids concentration to 25 mass%, and the mixture was stirred with a magnetic stirrer for 10 hours to obtain a solution for forming Layer A.
• (2) Mixed Method B The polymers and fillers shown in Table 1 were mixed in the contents (mass %) shown in Table 1, and N-methylpyrrolidone was added to adjust the solids concentration to 25 mass %.
• a fluororesin film (product name "Nitoflon #900UL", manufactured by Nitto Denko Corporation, average thickness 50 ⁇ m) was used as the support.
• the surfaces of the Layer A side of each of the obtained Films A1 and A2 were overlapped with the surface of the Layer B side of Film B, and a lamination process was performed for 1 minute using a laminator (product name "Vacuum Laminator V-130", manufactured by Nikko Materials Co., Ltd.) at 140°C and a lamination pressure of 0.4 MPa, to obtain a laminate in which the copper foil, Layer A, Layer B, and support were laminated in this order.
• the support on the Layer B side was peeled off, and a laminate (single-sided copper-clad laminate) in which the copper foil, Layer A, and Layer B were laminated in this order was obtained.
• an LCP film product name "Vexstar CTQ", manufactured by Kuraray Co., Ltd., average thickness 50 ⁇ m
• the treated surface of copper foil M3 was laminated at 300° C. using a thermocompression bonding machine to obtain a laminate (film A3) in which layer A was formed on the copper foil.
• Each of the surfaces of the layer A side of film A3 and the surface of the layer B side of film B were overlapped, and a lamination process was performed for 1 minute using a laminator (product name "Vacuum Laminator V-130", manufactured by Nikko Materials Co., Ltd.) at 140°C and a lamination pressure of 0.4 MPa, to obtain a laminate in which the copper foil, layer A, layer B, and support were laminated in this order.
• the support on the layer B side was peeled off, and a laminate (single-sided copper-clad laminate) in which the copper foil, layer A, and layer B were laminated in this order was obtained.
• the obtained layer A forming solution and layer B forming solution were fed to a slot die coater equipped with a slide coater, and applied to the treated surface of the support shown in Table 1 by adjusting the flow rate so as to obtain the film thickness shown in Table 1.
• the solvent was removed from the coating film by drying at 40°C for 4 hours.
• the temperature was then raised from room temperature (25°C) to 300°C at a rate of 1°C/min under a nitrogen atmosphere.
• a heat treatment was performed at 300°C for 2 hours to obtain a laminate (single-sided copper-clad laminate) in which the copper foil, layer A, and layer B were laminated in this order.
• thermocompression bonding machine product name "MP-SNL", manufactured by Toyo Seiki Seisakusho Co., Ltd.
• Example 14 a four-layer copper-clad laminate was produced by thermocompression bonding in a degassed state using a vacuum press (product name: "Vacuum Press for High-Temperature PCB Molding” manufactured by Kitagawa Seiki Co., Ltd.) instead of a thermocompression bonding machine.
• a vacuum press product name: "Vacuum Press for High-Temperature PCB Molding” manufactured by Kitagawa Seiki Co., Ltd.
• thermocompression bonding machine product name "MP-SNL", manufactured by Toyo Seiki Seisakusho Co., Ltd.
• a vacuum press product name: "Vacuum press for high temperature PCB molding", manufactured by Kitagawa Seiki Co., Ltd.
• thermocompression bonding machine was used instead of a thermocompression bonding machine to produce a double-sided copper-clad laminate by thermocompression bonding in a degassed state.
• the surfaces of the copper foils on both sides of the double-sided copper-clad laminate were roughened, and a dry film resist was attached.
• the substrate was exposed to light so that the wiring pattern remained, developed, etched, and the dry film was removed to produce a substrate A with a wiring pattern having a line/space of 100 ⁇ m/100 ⁇ m including a ground line and three pairs of signal lines on both sides of the substrate.
• the length of the signal line was 50 mm, and the width was set so that the characteristic impedance was 50 ⁇ .
• a copper foil (product name "MT18FL", average thickness 1.5 ⁇ m, with carrier copper foil (thickness 18 ⁇ m), manufactured by Mitsui Mining & Smelting Co., Ltd.) and a liquid crystal polymer film (product name "CTQ-50", average thickness 50 ⁇ m, manufactured by Kuraray Co., Ltd.) were prepared as a substrate.
• the copper foil and the substrate were stacked in this order so that the treated surface of the copper foil was in contact with the substrate.
• a laminator product name "Vacuum Laminator V-130", manufactured by Nikko Materials Co., Ltd.
• thermocompression bonding machine product name "MP-SNL", manufactured by Toyo Seiki Seisakusho Co., Ltd.
• a vacuum press product name: "Vacuum press for high temperature PCB molding", manufactured by Kitagawa Seiki Co., Ltd.
• thermocompression bonding machine was used instead of a thermocompression bonding machine to produce a single-sided copper-clad laminate by thermocompression bonding in a degassed state.
• the carrier copper foil on the opposite side of the substrate of the single-sided copper-clad laminate was peeled off, and the surface of the exposed 1.5 ⁇ m copper foil was roughened and a dry film resist was attached. After pattern exposure and development, plating was performed on the area where the resist pattern was not arranged. Furthermore, the dry film resist was peeled off, and the copper exposed by the peeling process was removed by flash etching to produce a substrate B with a wiring pattern having a line/space of 20 ⁇ m/20 ⁇ m.
• the prepared substrate having a wiring pattern was superimposed on the layer B side of the prepared single-sided copper-clad laminate, and hot pressed at 160° C. and 4 MPa for 1 hour to obtain a wiring board.
• the obtained wiring board had a wiring pattern (ground line and signal line) embedded therein, and when substrate A with a wiring pattern was used, the thickness of the wiring pattern was 18 ⁇ m, and when substrate B with a wiring pattern was used, the thickness of the wiring pattern was 12 ⁇ m.
• the cross section of the double-sided copper-clad laminate was exposed using a cryomicrotome.
• layers A and B were identified, and the modulus of elasticity of layers A and B at 160°C was measured as the indentation modulus using a nanoindentation method.
• the indentation modulus was measured by applying a load at a loading rate of 0.28 mN/sec with a Vickers indenter using a microhardness tester (product name "DUH-W201", manufactured by Shimadzu Corporation), holding the maximum load of 10 mN for 10 seconds, and then unloading at a loading rate of 0.28 mN/sec.
• the cross section sample was measured at 20 arbitrary positions at 160°C, and the average value was taken as the modulus of elasticity.
• Table 2 shows the elastic modulus of material a and material b at 25°C, 40°C, 100°C, 160°C, 230°C, and 260°C.
• ⁇ 0.6 means that the elastic modulus is 0.6 MPa or more.
• ⁇ 0.6 means that the elastic modulus is less than 0.6 MPa.
• the surface roughness Rc of the side of Layer A on which Layer B was disposed was measured by exposing a cross section of the double-sided copper-clad laminate with a cryomicrotome, extracting the interface of Layer A on the Layer B side with an optical microscope, and measuring the average height Rc in accordance with JIS B0601 2001.
• the evaluation length was 500 ⁇ m.
• the copper foil of the double-sided copper-clad laminate was removed with an aqueous solution of ferric chloride, washed with pure water, and dried to obtain a polymer film, which was then used for the measurement.
• the dielectric loss tangent was measured at a frequency of 10 GHz by a resonance perturbation method.
• a 10 GHz cavity resonator (Kanto Electronics Application Development Co., Ltd., "CP531") was connected to a network analyzer (Agilent Technology, Inc., "E8363B”), and the polymer film was inserted into the cavity resonator.
• the dielectric loss tangent of the polymer film was measured from the change in resonance frequency before and after insertion for 96 hours under an environment of 25°C temperature and 60% RH.
• the metal layer of the prepared double-sided copper-clad laminate was electrolytically plated to a thickness of 50 ⁇ m.
• the support side was fixed to a flat plate with double-sided adhesive tape, and the metal layer was peeled from the double-sided copper-clad laminate at a speed of 50 mm/min in an environment of 25° C. and 50% relative humidity by the 90° method according to JIS C 5016 (1994), and the peel strength (N/cm) between Layer B and the metal layer was measured.
• the four-layer copper-clad laminate was cut into a size of 30 mm x 30 mm to prepare an evaluation sample.
• the evaluation sample was treated for 168 hours in a thermohygrostat at a temperature of 85°C and a relative humidity of 85%.
• the evaluation sample was then placed in an oven set at 260°C and heated for 15 minutes.
• the evaluation sample after heating was cut with a razor, and the cross section was observed with an optical microscope, and the peeling state was visually evaluated.
• B Peeling was observed between Layer B and the copper foil with a width of 0.5 mm or less.
• C Peeling was observed between layer B and the copper foil with a width of more than 0.5 mm and 1 mm or less.
• D Peeling was observed between layer B and the copper foil with a width of more than 1 mm.
• the elastic modulus of material a and material b is 0.60 MPa or more. It can be seen that at 160° C. or higher, the elastic modulus of material a is less than 0.60 MPa, and the elastic modulus of material b is 0.60 MPa or higher.
• Examples 1 to 14 include a metal substrate placement process, a pressure process, a heating process, a cooling process, and a load-removing process in this order, and therefore have excellent step conformability and heat resistance.
• Comparative Example 1 the step of pressing at a temperature at which the elastic modulus of each of material a and material b becomes 0.60 MPa or more was not performed, and it was found that the heat resistance was poor.
• Comparative Example 2 the absolute value of the pressure change rate from Step 1 in Step 2 exceeded 10%, indicating poor heat resistance.
• the heating temperature in step 2 was a temperature at which the elastic modulus of material a was 0.60 MPa or more, and it was found that the material had poor heat resistance.
• Comparative Example 4 the load was removed before cooling, and it was found that the heat resistance was poor.
• Comparative Example 5 the elastic modulus of Layer B of the polymer film at 160° C. was more than 0.60 MPa, and it was found that the film was poor in conformity to unevenness and heat resistance.
• Example 5 the pressure in step 2 (heating process) was 2 MPa to 6 MPa, and it was found to have superior heat resistance compared to Example 6.
• Example 4 the heating temperature in step 2 (heating process) was 170°C to 260°C, and it was found to have superior heat resistance compared to Example 7.
• Example 4 the content of material b was 10% by mass to 30% by mass relative to the total mass of layer B, and it was found to have superior heat resistance compared to Example 13.

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