KR20230047000A - Metal-clad laminate, circuit substrate, electronic device and electronic apparatus - Google Patents

Abstract

An objective of the present invention is to suppress wrinkles and achieve compatibility of interfacial adhesion between a heat-pressed metal foil and a polyimide layer when metal foil is heat-pressed onto a single-sided metal-clad laminate at high temperature. The metal-clad laminate (100) includes a first metal layer (101) and an insulating resin layer (110) laminated on the first metal layer (101). The insulating resin layer (110) has a polyimide layer (A) which is in contact with the first metal layer (101), and a polyimide layer (B) which forms a resin surface on the opposite side of the first metal layer (101). Based on the glass transition temperature Tg of the polyimide layer (B), at any temperature within the range from Tg+20℃ to Tg+90℃, when the storage modulus of the polyimide layer (A) is E'(A) and the storage modulus of the polyimide layer (B) is E'(B), the ratio of the storage moduli E'(A)/E'(B) is 2.0 or more.

Description

Metal clad laminate, circuit board, electronic device and electronic device

The present invention relates to a metal-clad laminate, a circuit board obtained by circuit processing thereof, and an electronic device and electronic equipment using the same.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, demand for flexible printed circuits (FPCs) that are thin, lightweight, flexible, and have excellent durability even after repeated bending is increasing. there is. Since the FPC can be mounted in a three-dimensional and high-density manner even in a limited space, its use is expanding to parts such as wires, cables, and connectors of movable parts of electronic devices such as HDDs, DVDs, and smartphones, for example.

The FPC is typically manufactured by etching a metal layer of a metal-clad laminate such as a copper-clad laminate (CCL) serving as a material and subjecting it to wiring processing. Regarding the metal clad laminate, one using polyimide having a high storage elastic modulus for an insulating resin layer in contact with metal foil has been proposed (for example, Patent Literature 1 and Patent Literature 2).

In a single-sided metal-clad laminate having a metal layer on one side of a polyimide layer serving as an insulating resin layer, thermoplastic polyimide is widely used for the polyimide layer in contact with the metal layer. Specifically, in many cases, a laminated structure of a thermoplastic polyimide layer/non-thermoplastic polyimide layer/thermoplastic polyimide layer is employed from the metal layer side of the single-sided metal-clad laminate. When producing a double-sided metal-clad laminate by thermally compressing metal foil to the outermost thermoplastic polyimide layer of the single-sided metal-clad laminate having such a structure, in order to ensure sufficient peel strength between the laminated surface of the outermost thermoplastic polyimide layer and the metal foil. , It is necessary to perform thermal compression bonding at a high temperature of about 200 to 400°C. However, when thermal compression bonding is performed at a high temperature, there has been a problem that the thermoplastic polyimide layer on the side in contact with the metal layer of the single-sided metal-clad laminate is softened, and wrinkles easily enter the adjacent metal layer. The above problem can be solved by lowering the thermocompression bonding temperature and suppressing the softening of the thermoplastic polyimide layer, but in that case, the adhesion between the thermoplastic polyimide layer on the laminate surface side and the metal foil bonded by thermocompression is not sufficient, and the reliability of adhesion after wiring processing. cannot obtain

Japanese Unexamined Patent Publication No. 2020-104340 Japanese Unexamined Patent Publication No. 2006-051800

An object of the present invention is to achieve both suppression of wrinkles when thermally compressing metal foil to a single-sided metal-clad laminate at high temperature, and coexistence of interfacial adhesion between the thermally compressed metal foil and the polyimide layer.

As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by making the storage modulus of the thermoplastic polyimide layer in contact with the metal layer of the single-sided metal-clad laminate higher than the storage modulus of the thermoplastic polyimide layer on the side of the laminated surface. came to complete the invention.

That is, the metal clad laminate of the present invention,

a first metal layer;

A metal clad laminate having an insulating resin layer laminated on the first metal layer,

The insulating resin layer has a polyimide layer (A) in contact with the first metal layer and a polyimide layer (B) forming a resin surface on the opposite side to the first metal layer,

Based on the glass transition temperature Tg of the polyimide layer (B), the storage modulus of the polyimide layer (A) at any temperature within the range from Tg + 20 ° C to Tg + 90 ° C is E' (A) , When the storage modulus of the polyimide layer (B) is taken as E' (B), the ratio E' (A)/E' (B) of the storage modulus is 2.0 or more.

In the metal clad laminate of the present invention, the insulating resin layer may have a polyimide layer (C) laminated between the polyimide layer (A) and the polyimide layer (B).

The metal clad laminate of the present invention,

The thickness of the first metal layer may be in the range of 6 to 18 µm, and the tensile modulus may be in the range of 10 to 100 GPa.

The metal-clad laminate of the present invention may further include a second metal layer laminated in contact with the resin surface of the polyimide layer (B).

In the metal clad laminate of the present invention, the peel strength of the second metal layer and the polyimide layer (B) may be 0.7 kN/m or more.

The circuit board of the present invention is formed by circuit processing either one or both of the first metal layer and the second metal layer in the metal clad laminate.

The circuit board of the present invention is a circuit board formed by circuit processing of the first metal layer in the metal-clad laminate.

The electronic device of the present invention includes the circuit board.

The electronic device of the present invention includes the circuit board.

The metal-clad laminate of the present invention is a ratio E' of the storage modulus E' (A) of the polyimide layer (A) in contact with the first metal layer and the storage modulus E' (B) of the polyimide layer (B) on the side of the laminated surface. (A) When /E'(B) is 2.0 or more, generation|occurrence|production of wrinkles in a 1st metal layer can be prevented even if it thermally compresses metal foil to the lamination surface side at high temperature. Therefore, it becomes possible to achieve both the interfacial adhesion between the metal foil bonded by thermal compression and the polyimide layer and suppression of wrinkles of the first metal layer when the metal foil is thermally compressed to the metal clad laminate at high temperature. Therefore, by using the metal-clad laminate of the present invention as an FPC material, reliability and yield of circuit boards can be improved.

1 is a schematic cross-sectional view showing the configuration of a metal clad laminate according to a first embodiment of the present invention.
Fig. 2 is a schematic cross-sectional view showing the configuration of a metal clad laminate according to a second embodiment of the present invention.
3 is an explanatory view showing a method for manufacturing a metal clad laminate according to a second embodiment of the present invention.
4 is an explanatory view showing a method for manufacturing a metal clad laminate according to a third embodiment of the present invention.
5 is a schematic cross-sectional view showing the configuration of a metal clad laminate according to a third embodiment of the present invention.
6 is an explanatory diagram showing a method for manufacturing a metal clad laminate according to a fourth embodiment of the present invention.
Fig. 7 is a schematic cross-sectional view showing the configuration of a metal clad laminate according to a fourth embodiment of the present invention.

Next, embodiments of the present invention will be described with appropriate reference to the drawings.

<First Embodiment and Second Embodiment>

As shown in FIG. 1, a metal clad laminate 100 according to the first embodiment of the present invention includes a first metal layer 101 and an insulating resin layer 110 laminated on the first metal layer 101. are doing The metal-clad laminate 100 is a single-sided metal-clad laminate.

Further, as shown in Fig. 2, the metal clad laminate 200 according to the second embodiment of the present invention includes a first metal layer 101 and an insulating resin layer 110 laminated on the first metal layer 101. and a second metal layer 102 laminated on a surface opposite to the first metal layer 101 of the insulating resin layer 110. The metal-clad laminate 200 is a double-sided metal-clad laminate.

<Insulation resin layer>

The insulating resin layer 110 includes a polyimide layer (A) in contact with the first metal layer 101, a polyimide layer (B) forming a resin surface on the opposite side to the first metal layer 101, and a polyimide layer. It is equipped with the polyimide layer (C) laminated|stacked between (A) and the polyimide layer (B).

The polyimide layer (A) is a thermoplastic polyimide layer obtained by applying and drying a polyamic acid solution to the first metal layer 101 by a casting method and imidating it, and having a cast surface in contact with the first metal layer 101. is the mid layer.

The polyimide layer (B) is a thermoplastic polyimide layer having a laminated surface 110a for thermally compressing a metal foil or the like to be the second metal layer 102 .

The polyimide layer (C) serves as a base resin layer and maintains the mechanical strength of the insulating resin layer 110 . In the present invention, polyimide having different storage elastic moduli is used for the polyimide layer (A) and the polyimide layer (B) forming the insulating resin layer 110 .

Here, the non-thermoplastic polyimide is a polyimide that generally does not soften or exhibit adhesiveness even when heated, but in the present invention, the storage modulus at 30°C measured using a dynamic viscoelasticity measuring device (DMA) is 1.0 × 10 It is ⁹ Pa or more, and refers to a polyimide showing a storage modulus at 320°C of 3.0×10 ⁸ Pa or more. In addition, thermoplastic polyimide is generally a polyimide whose glass transition temperature (Tg) can be clearly confirmed, but in the present invention, the storage modulus at 30 ° C. measured using DMA is 1.0 × 10 ⁹ Pa or more , a polyimide having a storage modulus at 320°C of less than 3.0×10 ⁸ Pa.

Further, the insulating resin layer 110 may include any resin layer other than the polyimide layers (A) to (C) within a range not impairing the effects of the present invention.

The insulating resin layer 110 has a storage modulus of polyimide layer (A) at any temperature within the range from Tg + 20 ° C to Tg + 90 ° C, based on the glass transition temperature Tg of the polyimide layer (B) When the storage modulus of E' (A) and the polyimide layer (B) is set to E' (B), the ratio E' (A) / E' (B) of the storage elastic modulus is 2.0 or more.

When the metal foil to be the second metal layer 102 is bonded by thermal compression to the laminated surface 110a on the side of the polyimide layer (B) at a high temperature, the smaller the storage modulus E' (B) of the polyimide layer (B), the lower the heat resistance. The filling ability of the polyimide to the metal foil fine irregularities at the time of compression becomes good, and adhesion reliability increases. In addition, tension is applied at the time of thermal compression bonding, but the larger the storage elastic modulus E' (A) of the polyimide layer (A), the polyimide layer (A ) becomes difficult to soften, and generation of wrinkles in the first metal layer 101 can be suppressed. Therefore, by setting the ratio E'(A)/E'(B) to 2.0 or more, for example, at a high temperature within the range of 200 to 400°C, particularly within the range of 270 to 400°C, and further within the range of 320 to 400°C. In the case of thermal compression bonding, both the adhesion on the laminated surface 110a and suppression of wrinkles on the first metal layer 101 can be achieved. From this point of view, the ratio E'(A)/E'(B) is preferably 3 to 100, more preferably 5 to 60, and most preferably 10 to 40.

In the present invention, with respect to the glass transition temperature Tg of the polyimide layer (B), the ratio E'(A)/E'(B) satisfies the above stipulations at any temperature within the range from Tg+20°C to Tg+90°C. Any temperature within the range from Tg+20°C to Tg+90°C should satisfy the above requirements. Here, the storage modulus at any temperature within the range from the glass transition temperature Tg+20°C to Tg+90°C of the polyimide layer (B) is compared for the following reasons. That is, since softening of the polyimide layer (B) does not proceed at the glass transition temperature Tg of the polyimide layer (B), the temperature range until sufficiently softened is estimated and Tg+20°C is the lower limit, while the polyimide layer (B) is set as the lower limit. Even when the Tg of the mid layer (B) is slightly low, Tg + 90°C is set as the upper limit so that the practical thermal compression bonding temperature can be covered.

The glass transition temperature Tg of the polyimide layer (A) is not particularly limited as long as the effect of the invention is obtained, but is preferably within the range of 200°C or more and 400°C or less in order to ensure adhesion to the first metal layer 101. , more preferably within the range of 250°C or more and 380°C or less.

The storage elastic modulus E' (A) of the polyimide layer (A) is not particularly limited as long as the effect of the invention is obtained, but a higher one is effective in suppressing wrinkles of the first metal layer 101 at the time of thermal compression bonding. , preferably within the range of 1×10 ⁷ to 1×10 ¹⁰ Pa, more preferably within the range of 1×10 ⁸ to 1×10 ¹⁰ Pa.

The glass transition temperature Tg of the polyimide layer (B) is not particularly limited as long as the effect of the invention is obtained, but is preferably within the range of 200 ° C. or higher and 400 ° C. or lower to ensure adhesion to the second metal layer 102, It is more preferably within the range of 200°C or more and 350°C or less.

In addition, the storage modulus E' (B) of the polyimide layer (B) is not particularly limited as long as the effect of the invention is obtained, but a lower one is advantageous for improving adhesion, but when it is too low, thermal compression bonding becomes difficult. Therefore, it is preferably within the range of 1×10 ⁵ to 1×10 ⁸ Pa, more preferably within the range of 1×10 ⁶ to 9×10 ⁷ Pa.

In addition, Tg and storage elastic modulus of each polyimide layer are measured using a dynamic viscoelasticity measuring device (DMA).

Next, the resin structure of the polyimide layers (A) to (C) will be described. In the present invention, in order to set the ratio E'(A)/E'(B) to 2.0 or more, the polyimide layer (A) and the polyimide layer (B) forming the insulating resin layer 110 are made of polyimide of a different composition. It is preferable to use mead.

Polyimide is formed by imidizing polyamic acid and contains an acid anhydride residue and a diamine residue. Here, the acid anhydride residue represents a tetravalent group derived from an acid dianhydride, and the diamine residue represents a divalent group derived from a diamine compound. When the acid dianhydride and diamine compound as raw materials are reacted in substantially equal moles, the kinds and molar ratios of the acid dianhydride residues and diamine residues contained in the polyimide can be substantially matched to the kinds and molar ratios of the raw materials.

In the present invention, in the case of "polyimide", in addition to polyimide, polymers having an imide group in the molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxanimide, and polybenzimidazolimide, can be used. means a resin containing

Polyimide layer (A):

The acid dianhydride residue contained in the polyimide constituting the polyimide layer (A) is not particularly limited as long as the storage modulus E' (A) can be controlled, but an acid anhydride derived from pyromellitic dianhydride (PMDA) residue (hereinafter also referred to as "PMDA residue") and/or an acid anhydride residue derived from 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) (hereinafter also referred to as "BTDA residue") ) is preferred. It is preferable to contain PMDA residues and/or BTDA residues in a total amount of preferably 30 mol% or more, more preferably 50 to 100 mol%, relative to all acid anhydride residues. Both the PMDA residue and the BTDA residue are residues having an effect of increasing the storage elastic modulus. Therefore, if the total amount of PMDA residues and/or BTDA residues is less than 30 mol%, the storage modulus E' (A) of the polyimide layer (A) cannot be sufficiently increased, and the wrinkles of the first metal layer 101 are suppressed. effect becomes insufficient.

Examples of other acid dianhydride residues contained in the polyimide constituting the polyimide layer (A) include 4,4'-oxydiphthalic anhydride and 3,3',4,4'-biphenyltetracarboxylic acid. Acid dianhydride, 2,2',3,3'- or 2,3,3',4'-benzophenonetetracarboxylic acid dianhydride, 2,3',3,4'-diphenylethertetracarboxylic acid dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3",4,4"-, 2,3,3",4"- or 2,2",3,3"- p-terphenyltetracarboxylic acid dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3- or 3.4-dicarboxyphenyl)methane dianhydride water, bis(2,3- or 3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl)ethane dianhydride, 1,2,7, 8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracentetracarboxylic dianhydride, 2,2- Bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4, 5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene- 1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic Acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5 -Tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] and acid dianhydride residues derived from aromatic tetracarboxylic acid dianhydrides such as propane dianhydride.

The diamine residue contained in the polyimide constituting the polyimide layer (A) is not particularly limited as long as the storage modulus E' (A) can be controlled, but the backbone to which the aromatic rings constituting the main chain are connected at the para position. A diamine residue derived from a diamine compound of (hereinafter, also referred to as "para-position linked diamine residue") is preferable. With respect to all the diamine residues, it is preferable to contain para-position-linked diamine residues in a total amount of preferably 30% by mole or more, and more preferably within the range of 50 to 100% by mole. Since the para-position-linked diamine residue has molecular linearity, it has an effect of suppressing a decrease in the storage modulus E' (A) of the polyimide layer (A). Therefore, by containing the para-position-linked diamine residue within the above range, the storage modulus of the polyimide layer (A) is sufficiently increased, and softening of the polyimide layer (A) is suppressed even at a high temperature during thermal compression bonding, and the first metal layer of wrinkles can be suppressed. When the content of the para-positionally linked diamine residue is less than 30 mol%, the storage elastic modulus E' (A) of the polyimide layer (A) cannot be sufficiently increased, and the effect of suppressing wrinkles of the first metal layer 101 becomes insufficient. .

Representative examples of para-position linked diamine residues include 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl ( m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy-4,4'-diaminobiphenyl (m-POB ), 2,2'-n-propyl-4,4'-diaminobiphenyl (m-NPB), 2,2'-divinyl-4,4'-diaminobiphenyl (VAB), 4,4 '-diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl (TFMB), 4,4'-bis (4-aminophenoxy) biphenyl (BAPB ), 2,2'-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), bis [4- (4- from diamine compounds such as aminophenoxy)phenyl]sulfone, 1,4-bis(4-aminophenoxy)benzene (TPE-Q), and 4,4'-diaminodiphenyl ether (4,4'-DAPE) diamine moieties derived therefrom.

Among the para-position linked diamine residues, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) and 2, from the viewpoint of achieving both dimensional stability and adhesiveness with the first metal layer 101, Diamine moieties derived from 2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) are particularly preferred.

In addition, in this specification, "diamine compound" may have hydrogen atoms in the terminal two amino groups substituted, for example -NR ₁ R ₂ (where R ₁ and R ₂ are independently alkyl groups or the like meaning an arbitrary substituent).

Polyimide layer (B):

The acid dianhydride residue contained in the polyimide constituting the polyimide layer (B) is not particularly limited as long as the storage modulus E' (B) can be controlled, but PMDA residue and/or 3 The total amount of acid anhydride residues derived from 3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) (hereinafter also referred to as "BPDA residues") is preferably 30 mol% or more, more preferably Preferably, it is contained within the range of 50 to 100 mol%. BPDA residue can control the storage elastic modulus in a high temperature area|region by adjusting content. If the total amount of the PMDA residue and/or the BPDA residue is less than 30 mol%, the second metal layer 102 and chemical adhesion may not be sufficiently obtained.

As other acid dianhydride residues contained in the polyimide constituting the polyimide layer (B), those similar to those listed for the above polyimide layer (A) can be used.

The diamine residue contained in the polyimide constituting the polyimide layer (B) is not particularly limited as long as the storage modulus E' (B) can be controlled. The total amount of residues (hereinafter also referred to as "flexible diamine residues") is preferably 50 mol% or more, more preferably 80 to 100 mol%. Here, the flexible diamine compound means a diamine compound in which an aromatic ring constituting the main chain has a linking group having high flexibility such as -O- or -CH ₂ -, and more preferably contains a meta-position linking group. By containing the flexible diamine residue, the storage elastic modulus at a temperature higher than Tg can be lowered, and the thermocompression bonding property and adhesiveness with the second metal layer 102 can be improved. When the total amount of flexible diamine residues is less than 50 mol%, the storage elastic modulus of the polyimide layer (B) becomes too high, and the thermocompression bonding property and adhesiveness with the second metal layer 102 sometimes decrease.

Preferred specific examples of the flexible diamine residue include 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB), 4,4'-[ 2-methyl-(1,3-phenylene)bisoxy]bisaniline, 4,4'-[4-methyl-(1,3-phenylene)bisoxy]bisaniline, 4,4'-[5- Methyl-(1,3-phenylene)bisoxy]bisaniline, 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-dia Minodiphenylpropane, 3,4'-diaminodiphenylsulfide, 3,3'-diaminobenzophenone, (3,3'-bisamino)diphenylamine, 1,4-bis(3-aminophenone) cy)benzene, 3-[4-(4-aminophenoxy)phenoxy]benzenamine, 3-[3-(4-aminophenoxy)phenoxy]benzenamine, bis[4-(3-aminophenoxy) ) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] sulfone, Bis[4-(3-aminophenoxy)]benzophenone, Bis[4,4'-(3-aminophenoxy)]benzanilide, 4-[3-[4-(4-aminophenoxy)phenoxy ]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), etc. diamine residues derived from diamine compounds of Among these, diamine residues derived from 1,3-bis(4-aminophenoxy)benzene (TPE-R) and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) are , Since it has excellent flexibility, it is possible to lower the storage elastic modulus of the polyimide layer (B) and impart flexibility, which is most preferable.

As other diamine residues contained in the polyimide constituting the polyimide layer (B), those similar to those listed for the polyimide layer (A) can be used.

In the polyimide constituting the polyimide layers (A) and (B), the types of the acid dianhydride residues and the diamine residues, or the respective molar ratios in the case of applying two or more types of acid dianhydride residues or diamine residues, are selected. By doing so, it is possible to control the coefficient of thermal expansion, storage modulus, tensile modulus and the like. In addition, in the polyimide constituting the polyimide layers (A) and (B), when having a plurality of polyimide structural units, they may exist as blocks or may exist randomly, but it is preferable that they exist randomly. .

Polyimide layer (C):

There are no particular restrictions on the resin composition and storage elastic modulus of the polyimide constituting the polyimide layer (C), and known structures can be used.

In addition, the coefficient of thermal expansion (CTE) of the polyimide layer (C) is preferably 30 ppm/K or less in order to ensure the dimensional stability of the entire insulation resin layer 110, and the low expansion number within the range of -5 to 25 ppm/K. It is more preferable that it is a stratum.

The polyimide constituting the polyimide layers (A) to (C) is an optional component, for example, a plasticizer, another cured resin component such as an epoxy resin, a curing agent, a curing accelerator, an organic filler, an inorganic filler, a coupling agent, a flame retardant etc. can be suitably blended.

(Synthesis of polyimide)

In general, polyimide can be produced by reacting tetracarboxylic dianhydride and a diamine compound in a solvent to produce polyamic acid, followed by heating and cyclization. For example, polyamic acid, which is a precursor of polyimide, is obtained by dissolving tetracarboxylic dianhydride and a diamine compound in an almost equimolar amount in an organic solvent and stirring them at a temperature in the range of 0 to 100° C. for 30 minutes to 24 hours to cause a polymerization reaction. is obtained During the reaction, the reaction components are dissolved so that the resulting precursor is within the range of 5 to 30% by weight, preferably within the range of 10 to 20% by weight, in the organic solvent. As an organic solvent used for a polymerization reaction, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-p Rolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme , Cresol, etc. are mentioned. Two or more of these solvents may be used in combination, and also aromatic hydrocarbons such as xylene and toluene may be used in combination. The amount of the organic solvent used is not particularly limited, but it is preferable to adjust the amount used such that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 30% by weight.

Although it is usually advantageous to use the synthesized polyamic acid as a reaction solvent solution, it can be concentrated, diluted, or substituted with another organic solvent if necessary. In addition, polyamic acids are advantageously used because they generally have good solvent solubility. The solution viscosity of the polyamic acid is preferably in the range of 500 cP to 100,000 cP. Outside of this range, defects such as uneven thickness and streaks tend to occur in the film during coating work by a coater or the like. The method of imidizing the polyamic acid is not particularly limited, and, for example, heat treatment in which the polyamic acid is heated in the above solvent at a temperature in the range of 80 to 400°C for 1 to 24 hours is suitably employed.

The weight average molecular weight of the polyamic acid, which is a polyimide precursor constituting the polyimide layers (A) to (C), is preferably in the range of, for example, 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. . When the weight average molecular weight is less than 10,000, the strength of the insulating resin layer 110 decreases, and it tends to become brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity of the polyamic acid solution increases, and defects such as uneven thickness and streaks tend to occur during the coating operation.

<Thickness of each layer and its ratio>

The thickness of the polyimide layer (A) and the polyimide layer (B) is not particularly limited, and is preferably 1 μm or more, more preferably in the range of 2 to 10 μm, in order to ensure adhesion to the metal foil.

The thickness ratio of the polyimide layer (A) to the total thickness of the insulating resin layer 110 is in the range of 3 to 45% in order to suppress wrinkles in the first metal layer 101 at the time of thermal compression bonding. It is preferable, and it is more preferable that it exists in the range of 4 to 20%. If the thickness ratio is less than 3%, the effect of suppressing the occurrence of wrinkles in the first metal layer 101 may not be sufficiently obtained during thermal compression bonding, and if it exceeds 45%, the low expansion number in the insulating resin layer 110 may not be obtained. The dimensional stability of the insulating resin layer 110 tends to deteriorate at the point where the ratio of the stratum is reduced.

In addition, the thickness ratio of the polyimide layer (B) to the total thickness of the insulating resin layer 110 is preferably in the range of 3 to 45% in order to ensure adhesion to the second metal layer 102, It is more preferably within the range of 4 to 20%. If the thickness ratio is less than 3%, the adhesiveness by thermal compression may be insufficient, and if it exceeds 45%, the ratio of the low-expansion resin layer in the insulating resin layer 110 decreases, so the insulating resin layer 110 dimensional stability tends to deteriorate.

The thickness of the polyimide layer (C) is not particularly limited and can be appropriately set according to the purpose of use, but is preferably within a range of 3 to 75 µm, and more preferably within a range of 8 to 50 µm, for example. Further, in order to secure the dimensional stability of the insulating resin layer 110, the thickness ratio of the polyimide layer (C) to the thickness of the entire insulating resin layer 110 is preferably 30% or more, and is in the range of 60 to 92%. It is more preferable to be mine.

Insulation resin layer 110, in order to reduce dielectric loss at the time of transmission of a high-frequency signal, the dielectric loss tangent (Df) at 10 GHz when measured by a split post dielectric resonator (SPDR) as a whole of the insulation resin layer ) is preferably 0.004 or less. In order to improve the transmission loss of the circuit board, it is particularly important to control the dielectric loss tangent of the insulating resin layer, and by setting the dielectric loss tangent within the above range, the effect of lowering the transmission loss is increased. Therefore, when the metal clad laminate of the present invention is applied as a material for a circuit board for high frequency applications, transmission loss can be effectively reduced. If the dielectric loss tangent at 10 GHz exceeds 0.004, problems such as increased electrical signal loss on the transmission path of the high-frequency signal tend to occur. Although the lower limit of the dielectric loss tangent at 10 GHz is not particularly limited, it is necessary to consider controlling the physical properties of the insulating resin layer 110 .

<First metal layer and second metal layer>

The metal constituting the first metal layer 101 and the second metal layer 102 is not particularly limited as long as it can be used as a material for the FPC wiring layer, but examples include copper, aluminum, stainless steel, iron, silver, palladium, nickel, and metals selected from chromium, molybdenum, tungsten, zirconium, gold, cobalt, titanium, tantalum, zinc, lead, tin, silicon, bismuth, indium, alloys thereof, and the like. It is preferable to use metal foil for the first metal layer 101 and the second metal layer 102 from an adhesive viewpoint. In terms of conductivity, copper foil is particularly preferred. In addition, in the case of continuously producing the metal clad laminates 100 and 200, as the metal foil, a long metal foil having a predetermined thickness wound up in a roll shape is used.

The thickness of the first metal layer 101 is not particularly limited, but is preferably in the range of 6 to 18 μm, and more preferably in the range of 9 to 12 μm in the application as an FPC material. The tensile modulus of elasticity of the first metal layer 101 is not particularly limited, but is preferably in the range of 10 to 100 GPa, and more preferably in the range of 15 to 70 GPa for use as an FPC material. In addition, when the thickness and tensile modulus of the first metal layer 101 are smaller than the above ranges, mechanical strength may be insufficient during roll-to-roll conveyance, resulting in reduced handling properties. On the other hand, when the thickness and tensile modulus of the first metal layer 101 are larger than the above ranges, the handling property becomes good, but on the other hand, not only the flexibility is lowered, but also the first metal layer 101 at the time of thermal compression in the first place. Wrinkles rarely occur. However, in order to achieve both the mechanical strength and flexibility required for use as an FPC material, when the thickness and tensile modulus of the first metal layer 101 are within the above ranges, wrinkles do not occur during thermal compression bonding at a high temperature. Because it becomes easier, the effect of the present invention is remarkably expressed.

The thickness of the second metal layer 102 is not particularly limited, but is preferably within a range of 6 to 18 µm, and more preferably within a range of 9 to 12 µm for use as an FPC material. The tensile modulus of elasticity of the second metal layer 102 is not particularly limited, but is preferably in the range of 10 to 100 GPa, and more preferably in the range of 15 to 70 GPa for use as an FPC material.

<Method for Manufacturing Metal-clad Laminate>

As an aspect of the method for manufacturing the metal clad laminate 100, for example

[1] A method of applying and drying a solution of polyamic acid to the metal foil to be the first metal layer 101, followed by imidization (hereinafter, a casting method);

[2] A method in which a solution of polyamic acid is simultaneously laminated in multiple layers by multi-layer extrusion on the metal foil to be the first metal layer 101, applied and dried, and then imidated (hereinafter referred to as multi-layer extrusion method).

etc. can be mentioned.

The method of [1] above is, for example, the following steps;

(1a) a step of applying a solution of polyamic acid to the metal foil to be the first metal layer 101 and drying it;

(1b) A polyimide layer is formed on the first metal layer 101 by repeating steps (1a) and (1b), including a step of forming a polyimide layer by heat-treating and imidating polyamic acid on a metal foil. (A), the polyimide layer (C), and the polyimide layer (B) can be sequentially laminated. Moreover, after repeating a process (1a), you may imidize a plurality of layers collectively in a process (1b).

The method of [2] is the same as the method of [1] above, except that in step (1a) of the method of [1] above, a multi-layer extrusion is used to simultaneously coat and dry the laminated structure of polyamic acid. It can be done likewise.

In this embodiment, it is preferable to complete imidation of the polyamic acid on the first metal layer 101. Since the polyamic acid resin layer is imidized while being fixed to the first metal layer 101, the change in expansion and contraction of each polyimide layer in the imidation process can be suppressed, and thickness and dimensional accuracy can be maintained.

As shown in FIG. 3, the metal-clad laminate 200 is a metal foil 102A serving as the second metal layer 102 on the laminated surface 110a of the insulating resin layer 110 of the metal-clad laminate 100. It can be manufactured by thermal compression bonding. As the temperature conditions for the thermal compression bonding, it is preferable to perform within the range of Tg+20°C to Tg+90°C with respect to the glass transition temperature Tg of the polyimide layer (B).

In the metal-clad laminate 200 having the above structure, the peel strength of the second metal layer 102 and the polyimide layer (B) is 0.7 kN/m in order to ensure reliability after being processed into a circuit board such as FPC. It is preferably greater than or equal to 1.0 kN/m, more preferably equal to or greater than 1.0 kN/m.

<Third Embodiment>

A third embodiment, which is an application example of the present invention, will be described with reference to FIGS. 4 and 5 . 4 and 5, two metal-clad laminates 100 are arranged so that the polyimide layers (B) are opposed to each other, and the laminated surfaces 110a are thermally compressed to form a metal-clad laminate 300. ) can be produced. The metal clad laminate 300 of the present embodiment includes the first metal layer 101 / polyimide layer (A) / polyimide layer (C) / polyimide layer (B) / polyimide layer (B) / polyimide layer ( It is a double-sided metal-clad laminated board having a structure in which C) / polyimide layer (A) / first metal layer 101 are laminated in this order.

<Fourth Embodiment>

A fourth embodiment, which is an application example of the present invention, will be described with reference to FIGS. 6 and 7 . As shown in FIGS. 6 and 7 , two metal-clad laminates 100 are disposed so that the polyimide layers (B) face each other, and a bonding sheet BS is formed between these two metal-clad laminates 100. You may manufacture the metal clad laminated board 400 by inserting|inserting and bonding the bonding sheet BS and the two lamination surfaces 110a together by thermal compression. The metal clad laminate 400 is a first metal layer 101 / polyimide layer (A) / polyimide layer (C) / polyimide layer (B) / bonding sheet (BS) / polyimide layer (B) / polyimide A double-sided metal-clad laminate having a structure in which layer (C) / polyimide layer (A) / first metal layer 101 are laminated in this order.

<circuit board>

The metal-clad laminates 100, 200, 300, and 400 of the above embodiment are mainly useful as materials for circuit boards such as FPCs. That is, one embodiment of the present invention is formed by processing the first metal layer 101 and/or the second metal layer 102 of the metal-clad laminates 100, 200, 300, and 400 into a pattern by a conventional method to form a wiring layer. Circuit boards such as phosphorus FPCs can be manufactured. Although not shown, in the circuit board of the preferred embodiment, in the metal clad laminate (100, 200, 300, 400), either one or both of the first metal layer 101 and the second metal layer 102, or two One or both of the first metal layers 101 have a configuration in which wiring layers are substituted.

<Electronic devices/electronic devices>

The electronic device and electronic equipment of this embodiment are equipped with the said circuit board. Examples of the electronic device of the present embodiment include display devices such as liquid crystal displays, organic EL displays, and electronic paper, organic EL lights, solar cells, touch panels, camera modules, inverters, converters, and constituent members thereof. . Moreover, as an electronic device, HDD, DVD, a mobile phone, a smart phone, a tablet terminal, an electronic control unit (ECU) of a vehicle, a power control unit (PCU), etc. are mentioned, for example. In these electronic devices and electronic equipment, the circuit board is suitably used, for example, as components such as wiring of movable parts, cables, and connectors.

[Example]

An Example is shown below, and the characteristic of this invention is demonstrated more concretely. However, the scope of the present invention is not limited to the examples. In addition, in the following examples, unless otherwise specified, various measurements and evaluations are based on the following.

[Measurement of viscosity]

The viscosity in 25 degreeC was measured using the E-type viscometer (made by Brookfield, brand name; DV-II+Pro). The number of rotations was set so that the torque was 10% to 90%, and the value when the viscosity was stable was read 2 minutes after the start of the measurement.

[Measurement of Weight Average Molecular Weight]

It was measured by gel permeation chromatography (trade name; manufactured by Tosoh Corporation; HLC-8420GPC). Polystyrene was used as a standard material, and N,N-dimethylacetamide was used as an eluent.

[Measurement of Coefficient of Thermal Expansion (CTE)]

A polyimide film having a size of 3 mm × 20 mm was heated from 30 ° C. to 270 ° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Hitachi High-Tech Science Co., Ltd., trade name: TMA6100). After holding at that temperature for 10 minutes, it was cooled at a rate of 5°C/min, and the average coefficient of thermal expansion (coefficient of thermal expansion) from 250°C to 100°C was determined.

[Measurement of glass transition temperature (Tg) and storage modulus]

A polyimide film having a size of 5 mm × 20 mm was measured at a heating rate from 30 ° C. to 400 ° C. at a rate of 5 ° C./min and a frequency of 1 Hz using a dynamic viscoelasticity measuring device (DMA: manufactured by TA Instruments, product; RSA3) did The glass transition temperature was determined from the temperature of the maximum value of tanδ based on the main dispersion.

[Measurement of Peel Strength]

A sample obtained by circuit processing the copper foil (second copper foil layer) of the single-sided copper-clad laminate obtained by etching away the copper foil (first copper foil layer) on the coated surface side of the flexible copper-clad laminate to a width of 1.0 mm was prepared, and a polyimide layer was formed. The surface of was fixed to an aluminum plate with double-sided tape, and measured using a Tensilon tester (manufactured by Toyo Seiki Seisakusho, trade name: Strograph VE-1D). The copper foil was pulled at a rate of 50 mm/min in the direction of 180 degrees, and the median strength when peeling 10 mm was determined. "◎" for peeling strength of 1.3 kN/m or more, "○" for 1.0 kN/m or more and less than 1.3 kN/m, "△" for 0.7 kN/m or more and less than 1.0 kN/m, 0.7 kN/m A case of less than that was judged as "x".

[Evaluation of appearance shape]

The external appearance evaluation of the copper foil (1st copper foil layer) of the coated surface side in a flexible copper clad laminated board was performed. The sample after lamination was cut into a sheet of 350 mm × 250 mm in size and observed visually, and the case where the external shape was good and no wrinkles occurred was "◎", and the case where wrinkles at a level that did not affect circuit processing occurred in part "○", a case where wrinkles at a level that did not affect circuit processing occurred on the entire surface was judged as "Δ", and a case where wrinkles on a level that affected circuit processing occurred on the entire surface was judged as "×".

[Measurement of tensile modulus]

After the copper foil was cut out to a width of 12.7 mm, it was annealed at 380°C for 15 minutes, and then measured using a tensile compression tester (manufactured by Toyo Seiki Seisakusho, trade name: Strograph R-1). The tension was performed at a distance between chucks of 101.6 mm and a sweep speed of 10 mm/min, and the tensile modulus of elasticity was calculated from the slope of the obtained stress-displacement curve at a displacement of 0.2%.

[Measurement of dielectric loss tangent]

The dielectric loss tangent of the polyimide film at a frequency of 10 GHz was measured using a vector network analyzer (manufactured by Agilent, trade name; E8363C) and a split post dielectric resonator (SPDR resonator). In addition, the material used for the measurement is a polyimide film prepared by etching away the copper foil layer of the flexible copper-clad laminate; 24-26°C, humidity; It is left to stand on 45 to 55% conditions for 24 hours.

The abbreviations used in Examples and Comparative Examples represent the following compounds.

PMDA: pyromellitic dianhydride

BTDA: 3,3',4,4'-benzophenonetetracarboxylic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

TPE-R: 1,3-bis(4-aminophenoxy)benzene

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

DMAc: N,N-dimethylacetamide

Copper foil 1: rolled copper foil, thickness; 9 μm, tensile modulus after annealing; 36GPa

Copper foil 2: rolled copper foil, thickness; 12 μm, tensile modulus after annealing; 36GPa

Copper foil 3: rolled copper foil, thickness; 18 μm, tensile modulus after annealing; 36GPa

Copper foil 4: rolled copper foil, thickness; 18 μm, tensile modulus after annealing; 18GPa

(Synthesis Example 1)

21.43 parts by weight of m-TB (100.92 parts by mole) was added to 255.0 parts by weight of DMAc, stirred at room temperature for 30 minutes or longer, and completely dissolved. Subsequently, 16.26 parts by weight of PMDA (74.56 parts by mole) and 7.31 parts by weight of BPDA (24.85 parts by mole) were added, and stirring was performed at room temperature for 4 hours to obtain a polyamic acid solution 1 having a viscosity of 27,400 cP and a weight average molecular weight of 117,000.

On the substrate, polyamic acid solution 1 was uniformly applied to a cured thickness of about 25 μm, and then heated and dried at 140° C. or lower to remove the solvent. Further, a polyimide film 1 obtained by heat treatment was performed by raising the temperature stepwise from 140°C to 360°C, and imidation was completed to prepare a polyimide film 1. The obtained polyimide film 1 had a CTE of 23 ppm/K and was non-thermoplastic.

(Synthesis Example 2)

To 264.0 parts by weight of DMAc, 10.55 parts by weight of TPE-R (36.10 parts by mole) and 7.66 parts by weight of m-TB (33.10 parts by mole) were added, stirred at room temperature for 30 minutes or longer, and completely dissolved. Subsequently, 10.89 parts by weight of PMDA (49.93 parts by mole) and 6.90 parts by weight of BTDA (21.40 parts by mole) were added, and stirring was performed at room temperature for 4 hours to obtain a polyamic acid solution 2 having a viscosity of 3,800 cP and a weight average molecular weight of 180,000.

Polyimide film 2 prepared in the same manner as in Synthesis Example 1 had a Tg of 300°C and a storage modulus of 1.2×10 ⁹ Pa (270° C.), 1.2×10 ⁹ Pa (275° C.), and 2.0×10 ⁸ Pa (350° C.). and 1.3×10 ⁸ Pa (400° C.).

(Synthesis Example 3)

23.20 parts by weight of BAPP (56.53 parts by mole) was added to 264.0 parts by weight of DMAc, stirred at room temperature for 30 minutes or more, and completely dissolved. Subsequently, 11.95 parts by weight of PMDA (54.77 parts by mole) and 0.85 parts by weight of BPDA (2.88 parts by mole) were added, and stirring was performed at room temperature for 4 hours to obtain a polyamic acid solution 3 having a viscosity of 1,700 cP and a weight average molecular weight of 200,000.

Polyimide film 3 prepared in the same manner as in Synthesis Example 1 had a Tg of 320°C and a storage modulus of 1.5×10 ⁹ Pa (270° C.), 1.0×10 ⁸ Pa (275° C.), and 6.3×10 ⁷ Pa (350° C.). and 1.9×10 ⁷ Pa (400° C.).

(Synthesis Example 4)

To 264.0 parts by weight of DMAc, 17.94 parts by weight of TPE-R (61.36 parts by mole) and 0.69 parts by weight of m-TB (3.23 parts by mole) were added, stirred at room temperature for 30 minutes or longer, and completely dissolved. Next, 11.63 parts by weight of BPDA (39.53 parts by mole) and 5.75 parts by weight of PMDA (26.35 parts by mole) were added, and stirring was performed at room temperature for 4 hours to obtain a polyamic acid solution 4 having a viscosity of 2,500 cP and a weight average molecular weight of 121,000.

Polyimide film 4 produced in the same manner as in Synthesis Example 1 had a Tg of 225°C and a storage modulus of 1.0×10 ⁸ Pa (275°C).

(Synthesis Example 5)

To 264.0 parts by weight of DMAc, 15.33 parts by weight of TPE-R (52.43 parts by mole) and 2.78 parts by weight of m-TB (13.11 parts by mole) were added and stirred at room temperature for 30 minutes or more to dissolve completely. Subsequently, 12.79 parts by weight of BPDA (43.45 parts by mole) and 5.10 parts by weight of PMDA (23.40 parts by mole) were added, and stirring was performed at room temperature for 4 hours to obtain a polyamic acid solution 5 having a viscosity of 2,300 cP and a weight average molecular weight of 118,000.

The polyimide film 5 produced in the same manner as in Synthesis Example 1 had a Tg of 220°C and a storage modulus of 4.4×10 ⁷ Pa (270°C).

[Example 1]

On the copper foil 1, the polyamic acid solution 2 was applied to a cured thickness of 2 μm, followed by heating and drying at 140° C. or lower to remove the solvent. After applying the polyamic acid solution 1 thereon to a cured thickness of 21 μm, it was heated and dried at 140° C. or lower, and the solvent was removed. Further, polyamic acid solution 3 was applied thereon to a cured thickness of 2 μm, and then heated and dried at 140° C. or less to remove the solvent. Thereafter, the temperature was raised stepwise from 140°C to 360°C to imidize, thereby preparing a single-sided copper-clad laminate 1. Copper foil 2 was placed on the polyimide layer side of the obtained single-sided copper-clad laminate 1, and using a hot roll lamination machine, thermal lamination was continuously performed under the conditions of a lamination pressure of 1 kN/cm ² and a lamination temperature of 350°C to obtain a flexible copper-clad laminate 1. . Table 1 shows the evaluation results of flexible copper-clad laminate 1.

[Example 2]

Except having used copper foil 2 instead of copper foil 1, it carried out similarly to Example 1, and obtained flexible copper clad laminated board 2. Table 1 shows the evaluation results of flexible copper-clad laminate 2.

[Example 3]

Except having used copper foil 3 instead of copper foil 1, it carried out similarly to Example 1, and obtained flexible copper clad laminated board 3. Table 1 shows the evaluation results of the flexible copper-clad laminate 3.

[Example 4]

Except having used copper foil 4 instead of copper foil 1, it carried out similarly to Example 1, and obtained flexible copper clad laminated board 4. Table 1 shows the evaluation results of flexible copper-clad laminate 4.

[Example 5]

A flexible copper clad laminated board 5 was obtained in the same manner as in Example 1, except that copper foil 3 was used instead of copper foil 1 and the lamination temperature was 400°C. Table 1 shows the evaluation results of flexible copper-clad laminate 5.

[Example 6]

Flexible copper clad laminate 6 in the same manner as in Example 1, except that copper foil 2 was used instead of copper foil 1, and polyamic acid solution 4 was used instead of polyamic acid solution 3, and the lamination temperature was 275 ° C. got Table 1 shows the evaluation results of flexible copper-clad laminate 6.

[Example 7]

Flexible copper-clad laminate 7 in the same manner as in Example 1, except that copper foil 2 was used instead of copper foil 1, and polyamic acid solution 5 was used instead of polyamic acid solution 3, and the lamination temperature was 270 ° C. got Table 1 shows the evaluation results of flexible copper-clad laminate 7.

[Example 8]

Copper foil 2 was used instead of copper foil 1, polyamic acid solution 3 was used instead of polyamic acid solution 2, polyamic acid solution 5 was used instead of polyamic acid solution 3, and the lamination temperature was 270 ° C. Except having set it as, it carried out similarly to Example 1, and obtained the flexible copper clad laminated board 8. Table 1 shows the evaluation results of the flexible copper-clad laminate 8.

Comparative Example 1

Flexible copper-clad laminate 9 was obtained in the same manner as in Example 1, except that copper foil 2 was used instead of copper foil 1 and polyamic acid solution 2 was used instead of polyamic acid solution 3. Table 1 shows the evaluation results of the flexible copper-clad laminate 9.

Comparative Example 2

Copper foil 2 was used instead of copper foil 1, polyamic acid solution 5 was used instead of polyamic acid solution 2, polyamic acid solution 5 was used instead of polyamic acid solution 3, and the lamination temperature was 270 ° C. Except having set it as, it carried out similarly to Example 1, and obtained the flexible copper clad laminated board 10. Table 1 shows the evaluation results of the flexible copper-clad laminate 10.

In addition, "layer (A)" and "layer (B)" in Table 1 mean "polyimide layer (A)" and "polyimide layer (B)", respectively. In addition, both E'(A) and E'(B) in Table 1 mean the storage modulus at the lamination temperature.

The dielectric loss tangent (Df) at a frequency of 10 GHz of the polyimide films 1 to 10 prepared by etching away the copper foil layers of the flexible copper-clad laminates 1 to 10 obtained in Examples 1 to 8 and Comparative Examples 1 to 2 are shown in Table 2.

As mentioned above, although the embodiment of the present invention has been described in detail for the purpose of exemplifying, the present invention is not limited to the above embodiment, and various modifications are possible.

100, 200, 300, 400: metal clad laminate
101: first metal layer
102: second metal layer
102A: metal foil
110: insulating resin layer
110a: laminate side
(A): Polyimide layer (A)
(B): Polyimide layer (B)
(C): Polyimide layer (C)
BS: bonding sheet

Claims (9)

a first metal layer;
A metal clad laminate having an insulating resin layer laminated on the first metal layer,
The insulating resin layer has a polyimide layer (A) in contact with the first metal layer and a polyimide layer (B) forming a resin surface on the opposite side to the first metal layer,
Based on the glass transition temperature Tg of the polyimide layer (B), the storage modulus of the polyimide layer (A) at any temperature within the range from Tg + 20 ° C to Tg + 90 ° C is E' (A) , When the storage modulus of the polyimide layer (B) is taken as E' (B), the metal-clad laminate characterized in that the ratio E' (A) / E' (B) of the storage modulus is 2.0 or more. The metal-clad laminate according to claim 1, wherein the insulating resin layer has a polyimide layer (C) laminated between the polyimide layer (A) and the polyimide layer (B). The metal-clad laminate according to claim 1 or 2, wherein the first metal layer has a thickness in the range of 6 to 18 µm and a tensile modulus in the range of 10 to 100 GPa. The metal-clad laminate according to claim 1, further comprising a second metal layer laminated in contact with the resin surface of the polyimide layer (B). The metal-clad laminate according to claim 4, wherein the peel strength of the second metal layer and the polyimide layer (B) is 0.7 kN/m or more. A circuit board obtained by circuit processing of one or both of the first metal layer and the second metal layer in the metal clad laminate according to claim 4. A circuit board formed by circuit processing of the first metal layer in the metal-clad laminate according to claim 1. An electronic device comprising the circuit board according to claim 6 or 7. An electronic device comprising the circuit board according to claim 6 or 7.

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