JP7382447B2 - Double-sided metal-clad laminates and circuit boards - Google Patents

Description

The present invention relates to a metal-clad laminate, an adhesive sheet, an adhesive polyimide resin composition, and a circuit board.

In recent years, as electronic devices have become smaller, lighter, and space-saving, flexible printed circuit boards (FPCs) have become thinner, lighter, more flexible, and have excellent durability even after repeated bending. Demand for circuits is increasing. FPC can be mounted three-dimensionally and with high density even in a limited space, so its use is expanding, for example, for wiring of movable parts of electronic devices such as HDDs, DVDs, and smartphones, and parts such as cables and connectors. It is being done.

In addition to the above-mentioned increase in density, as the performance of equipment has progressed, it is also necessary to support higher frequencies of transmission signals. When transmitting a high frequency signal, if the transmission loss in the transmission path is large, problems such as electric signal loss and signal delay time will occur. Therefore, reducing transmission loss will become important in the future in FPC as well. In order to cope with higher frequencies, FPCs are used in which the dielectric layer is made of liquid crystal polymer, which is characterized by low dielectric constant and low dielectric loss tangent. However, although liquid crystal polymers have excellent dielectric properties, there is room for improvement in heat resistance and adhesion with metal layers.

Metal-clad laminates, which are used as materials for circuit boards such as FPCs, have a metal layer on which wiring is processed and an insulating resin layer bonded together via an adhesive layer made of adhesive resin (three-layer metal-clad laminates). ) is known (for example, Patent Document 1). In order to utilize such a three-layer metal-clad laminate for a circuit board that transmits high-frequency signals, it is considered important to improve the dielectric properties of the adhesive layer.

By the way, as technologies related to adhesive layers containing polyimide as a main component, there are two methods: polyimide made from a diamine compound derived from an aliphatic diamine such as dimer acid, and an amino compound having at least two primary amino groups as functional groups. It has been proposed to apply a crosslinked polyimide resin obtained by reacting , to an adhesive layer of a coverlay film (for example, Patent Document 2). The crosslinked polyimide resin of Patent Document 2 does not generate volatile components made of cyclic siloxane compounds, has excellent soldering heat resistance, and maintains the adhesive strength between the wiring layer and the coverlay film even in environments where it is repeatedly exposed to high temperatures. This has the advantage of not causing any deterioration. However, Patent Document 2 does not consider the possibility of application to high-frequency signal transmission or the application to an adhesive layer in a three-layer metal-clad laminate.

International publication WO2016/031960 Patent No. 5777944

An object of the present invention is to provide a metal-clad laminate and a circuit board that have an adhesive layer that has excellent adhesive properties, has a small dielectric constant and dielectric loss tangent, and is capable of reducing transmission loss even in high-frequency transmission.

As a result of intensive research, the present inventors have found that polyimide is used in the adhesive layer that functions to bond the wiring layer and the insulating resin layer in a circuit board, and the type and amount of the monomer that is the raw material for the polyimide is controlled. The present invention was completed based on the discovery that it is possible to achieve a low dielectric constant and a low dielectric loss tangent while maintaining excellent adhesion.

The metal-clad laminate of the present invention includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. It is something that you have.
The adhesive layer in the metal-clad laminate of the present invention includes polyimide containing a tetracarboxylic acid residue and a diamine residue.
And, the polyimide contains, based on 100 mole parts of the diamine residue,
It is characterized by containing 50 mole parts or more of a diamine residue derived from a dimer acid type diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group.

In the metal-clad laminate of the present invention, the polyimide is made of a tetracarboxylic anhydride represented by the following general formula (1) and/or (2) based on 100 mole parts of the tetracarboxylic acid residue. The resulting tetracarboxylic acid residue may be contained in a total amount of 90 parts by mole or more.

In the general formula (1), X represents a single bond or a divalent group selected from the following formula, and in the general formula (2), the cyclic moiety represented by Y is a 4-membered ring or a 5-membered ring. , represents forming a cyclic saturated hydrocarbon group selected from a 6-membered ring, a 7-membered ring, or an 8-membered ring.

In the above formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-O-C(=O)-CH ₃ )-CH ₂ -, but n is 1 Indicates an integer between ~20.

In the metal-clad laminate of the present invention, the polyimide contains:
The diamine residue derived from the dimer acid type diamine may be contained within the range of 50 mole parts or more and 99 mole parts or less,
Contains a diamine residue derived from at least one diamine compound selected from the diamine compounds represented by the following general formulas (B1) to (B7) in a range of 1 to 50 mole parts. Good too.

In formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents -O-, -S-, -CO- , -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, and n ₁ is independently Indicates an integer from 0 to 4. However, from equation (B3), those that overlap with equation (B2) are excluded, and from equation (B5), those that overlap with equation (B4) are excluded.

In the metal-clad laminate of the present invention, the metal layer may be made of copper foil, and a surface of the copper foil that comes into contact with the adhesive layer may be subjected to anti-rust treatment.

The circuit board of the present invention is formed by processing the metal layer of any of the metal clad laminates described above into wiring.

The adhesive sheet of the present invention includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. This is an adhesive sheet for forming the adhesive layer in a stretched laminate.
The adhesive sheet of the present invention includes polyimide containing a tetracarboxylic acid residue and a diamine residue.
And, the polyimide contains, based on 100 mole parts of the diamine residue,
It is characterized by containing 50 mole parts or more of a diamine residue derived from a dimer acid type diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group.

In the adhesive sheet of the present invention, the polyimide is derived from a tetracarboxylic anhydride represented by the above general formula (1) and/or (2) based on 100 mol parts of the tetracarboxylic acid residue. may contain 90 mole parts or more of tetracarboxylic acid residues in total.

In the adhesive sheet of the present invention, the polyimide contains:
The diamine residue derived from the dimer acid type diamine may be contained within the range of 50 mole parts or more and 99 mole parts or less,
Contains a diamine residue derived from at least one diamine compound selected from the diamine compounds represented by the above general formulas (B1) to (B7) in a range of 1 to 50 mole parts. Good too.

The adhesive polyimide resin composition of the present invention includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. A composition for forming the adhesive layer in a metal-clad laminate having the following.
The adhesive polyimide resin composition of the present invention contains a polyimide containing a tetracarboxylic acid residue and a diamine residue.
And, the polyimide contains, based on 100 mole parts of the diamine residue,
It is characterized by containing 50 mole parts or more of a diamine residue derived from a dimer acid type diamine in which two terminal carboxylic acid groups of a dimer acid are substituted with a primary aminomethyl group or an amino group.

In the adhesive polyimide resin composition of the present invention, the polyimide contains tetracarboxylic acid anhydride represented by the above general formula (1) and/or (2) based on 100 mole parts of the tetracarboxylic acid residue. It may contain a total of 90 mole parts or more of tetracarboxylic acid residues derived from compounds.

In the adhesive polyimide resin composition of the present invention, the polyimide contains:
The diamine residue derived from the dimer acid type diamine may be contained within the range of 50 mole parts or more and 99 mole parts or less,
Contains a diamine residue derived from at least one diamine compound selected from the diamine compounds represented by the above general formulas (B1) to (B7) in a range of 1 to 50 mole parts. Good too.

The metal-clad laminate of the present invention has an adhesive layer formed of polyimide into which specific tetracarboxylic acid residues and diamine residues have been introduced, thereby ensuring adhesive properties and achieving low dielectric constant and dielectric loss tangent. did. By using the metal-clad laminate of the present invention, it is also possible to apply it to, for example, a circuit board that transmits a high frequency signal of 10 GHz or more. Therefore, it is possible to improve the reliability and yield of the circuit board.

Embodiments of the present invention will be described in detail.

[Metal-clad laminate]
The metal-clad laminate of this embodiment includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. It is a so-called three-layer metal-clad laminate. In the three-layer metal-clad laminate, the adhesive layer may be provided on one or both sides of the insulating resin layer, and the metal layer may be provided on one or both sides of the insulating resin layer via the adhesive layer. . That is, the metal-clad laminate of this embodiment may be a single-sided metal-clad laminate or a double-sided metal-clad laminate. A single-sided FPC or a double-sided FPC can be manufactured by processing the wiring circuit by etching the metal layer of the metal-clad laminate of this embodiment.

<Insulating resin layer>
The insulating resin layer is not particularly limited as long as it is made of a resin that has electrical insulation properties, and examples include polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, ETFE, etc. However, it is preferably made of polyimide. The polyimide layer constituting the insulating resin layer may be a single layer or multiple layers, but preferably includes a non-thermoplastic polyimide layer. Here, "non-thermoplastic polyimide" generally refers to polyimide that does not soften or exhibit adhesive properties even when heated, but in the present invention, it was measured using a dynamic viscoelasticity measuring apparatus (DMA). A polyimide having a storage modulus of 1.0×10 ⁹ Pa or more at 30°C and a storage modulus of 3.0×10 ⁸ Pa or more at 300°C.

Polyimide is produced by imidizing a precursor polyamic acid obtained by reacting a specific acid anhydride and a diamine compound. An example is understood (the same applies to the thermoplastic polyimide forming the adhesive layer described below). Note that the polyimide in the present invention includes, in addition to so-called polyimide, those having an imide group in the structure such as polyamideimide, polybenzimidazole, polyimide ester, polyetherimide, and polysiloxane imide.

(acid anhydride)
Examples of acid anhydrides used in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer include 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 1 ,4-phenylenebis(trimellitic acid monoester) dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 2,3', 3,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-, 2,3,3',4'- or 3,3',4,4'-benzophenonetetracarboxylic dianhydride Anhydride, 2,3',3,4'-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3'',4,4''-,2 ,3,3'',4''- or 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3- or 3,4- dicarboxyphenyl)-propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride, 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-anthracenetetracarboxylic 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-naphthalene Tetracarboxylic 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 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 Anhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylenebis(trimellitic) (acid monoester acid anhydride), acid dianhydride such as ethylene glycol bisanhydrotrimellitate.

(Diamine compound)
Examples of the diamine compound used in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer include aromatic diamine compounds and aliphatic diamine compounds. Specific examples thereof include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n- Propyl-4,4'-diaminobiphenyl (m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[ 4-(3-aminophenoxy)phenyl] sulfone, bis[4-(3-aminophenoxy)biphenyl, bis[1-(3-aminophenoxy)]biphenyl, bis[4-(3-aminophenoxy)phenyl]methane , bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]benzophenone, 9,9-bis[4-(3-aminophenoxy)phenyl]fluorene, 2,2- Bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl-4,4'- Diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis(p-aminocyclohexyl)methane, bis(p-β-amino-t-butylphenyl)ether, bis(p-β) -Methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2 ,6-diaminonaphthalene, 2,4-bis(β-amino-t-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m -xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4, 4'-Diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 6-amino-2-(4-aminophenoxy)benzo Examples include diamine compounds such as oxazole, 1,3-bis(3-aminophenoxy)benzene, and dimer acid type diamines in which the two terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups. .

In the non-thermoplastic polyimide, by selecting the types of acid anhydrides and diamine compounds mentioned above, and the molar ratio of two or more acid anhydrides and diamine compounds, the coefficient of thermal expansion, storage modulus, Tensile modulus etc. can be controlled. In addition, when non-thermoplastic polyimide has multiple polyimide structural units, they may exist as blocks or randomly, but from the viewpoint of suppressing in-plane variations, it is preferable that they exist randomly. preferable.

The thickness of the insulating resin layer is, for example, preferably in the range of 1 to 125 μm, more preferably in the range of 5 to 50 μm. If the thickness of the insulating resin layer is less than the above lower limit, problems such as insufficient electrical insulation may occur. On the other hand, if the thickness of the insulating resin layer exceeds the above upper limit, problems such as warping of the metal clad laminate will occur. Further, the ratio of the thickness of the insulating resin layer to the thickness of the adhesive layer (thickness of the insulating resin layer/thickness of the adhesive layer) is preferably within the range of 0.5 to 2.0. By setting such a ratio, warping of the metal-clad laminate can be suppressed.

The non-thermoplastic polyimide layer constituting the insulating resin layer has low thermal expansion, and the coefficient of thermal expansion (CTE) is preferably in the range of 10 ppm/K or more and 30 ppm/K or less, more preferably 10 ppm/K or more and 25 ppm/K or less. is within the range of If the CTE is less than 10 ppm/K or more than 30 ppm/K, warping may occur or dimensional stability may decrease. A polyimide layer having a desired CTE can be obtained by appropriately changing the combination of raw materials used, the thickness, and drying/curing conditions.

For example, when applied to a circuit board, the insulating resin layer has a dielectric loss tangent (Tan δ) of 0.02 or less, more preferably 0.0005 or more and 0.01 or less at 10 GHz, in order to suppress deterioration of dielectric loss. It is preferably within a range of 0.001 or more and 0.008 or less. If the dielectric loss tangent of the insulating resin layer at 10 GHz exceeds 0.02, when used in a circuit board such as an FPC, inconveniences such as electrical signal loss on a high frequency signal transmission path are likely to occur. On the other hand, the lower limit of the dielectric loss tangent of the insulating resin layer at 10 GHz is not particularly limited, but the control of the physical properties of the insulating resin layer of the circuit board is taken into consideration.

When the insulating resin layer is applied, for example, as an insulating layer of a circuit board, in order to ensure impedance matching, it is preferable that the insulating resin layer as a whole has a dielectric constant of 4.0 or less at 10 GHz. If the dielectric constant of the insulating resin layer exceeds 4.0 at 10 GHz, it will lead to worsening of the dielectric loss of the insulating resin layer when used in circuit boards such as FPCs, resulting in electrical signal loss on the high-frequency signal transmission path. Inconveniences are more likely to occur.

The insulating resin layer may contain a filler if necessary. Examples of fillers include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and metal salts of organic phosphinic acids. These can be used alone or in combination of two or more.

<Adhesive layer>
The adhesive layer contains polyimide containing a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride and a diamine residue derived from a diamine compound, and is preferably made of thermoplastic polyimide. Here, "thermoplastic polyimide" generally refers to 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. It refers to a polyimide whose storage elastic modulus at 300° C. is 0×10 ⁸ Pa or more and less than 3.0×10 ⁷ Pa. In the present invention, the term "tetracarboxylic acid residue" refers to a tetravalent group derived from tetracarboxylic dianhydride, and the term "diamine residue" refers to a divalent group derived from a diamine compound. means.

(tetracarboxylic acid residue)
The thermoplastic polyimide forming the adhesive layer is derived from a tetracarboxylic anhydride represented by the following general formula (1) and/or (2) based on 100 mole parts of the tetracarboxylic acid residue. It is preferable to contain a total of 90 parts by mole or more of tetracarboxylic acid residues (hereinafter sometimes referred to as "tetracarboxylic acid residues (1)" and "tetracarboxylic acid residues (2)"). In the present invention, by containing the tetracarboxylic acid residues (1) and/or (2) in a total of 90 mol parts or more based on 100 mol parts of the tetracarboxylic acid residues, the thermoplastic material forming the adhesive layer can be used. It is preferable because it imparts solvent solubility to the polyimide and facilitates achieving both flexibility and heat resistance of the thermoplastic polyimide. If the total amount of tetracarboxylic acid residues (1) and/or (2) is less than 90 parts by mole, the solvent solubility of the thermoplastic polyimide tends to decrease.

In the general formula (1), X represents a single bond or a divalent group selected from the following formula, and in the general formula (2), the cyclic moiety represented by Y is a 4-membered ring or a 5-membered ring. , indicates the formation of a cyclic saturated hydrocarbon group selected from a 6-membered ring, a 7-membered ring, or an 8-membered ring.

In the above formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-O-C(=O)-CH ₃ )-CH ₂ -, but n is 1 Indicates an integer between ~20.

Examples of the tetracarboxylic dianhydride for inducing the tetracarboxylic acid residue (1) include 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride (ODPA), 4, 4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), p-phenylene bis(tri Examples include mellitic acid monoester acid anhydride).

In addition, examples of the tetracarboxylic dianhydride for inducing the tetracarboxylic acid residue (2) include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4- Cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,4,5-cycloheptanetetracarboxylic dianhydride, 1,2,5,6- Examples include cyclooctanetetracarboxylic dianhydride.

The thermoplastic polyimide forming the adhesive layer may be a tetracarboxylic acid derived from an acid anhydride other than the tetracarboxylic anhydride represented by the above general formula (1) or (2), to the extent that the effects of the invention are not impaired. can contain residues. Examples of acid anhydride residues other than tetracarboxylic acid residues (1) or (2) include the acid anhydrides used in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer in the above-mentioned insulating resin layer. The residues of things can be mentioned.

(diamine residue)
The thermoplastic polyimide forming the adhesive layer contains at least 50 moles of dimer acid diamine residues derived from dimer acid diamines, for example from 50 moles to 99 moles, based on 100 moles of diamine residues. It is preferably contained within the range of 80 mol parts or more, for example 80 mol parts or more and 99 mol parts or less. By containing the dimer acid type diamine residue in the above amount, the dielectric properties of the adhesive layer can be improved, and the flexibility required for the adhesive layer can be ensured. If the dimer acid type diamine residue is less than 50 mole parts with respect to 100 mole parts of the diamine residue, sufficient adhesion cannot be obtained as an adhesive layer interposed between the insulating resin layer and the metal layer. Also, the metal-clad laminate may warp.

Here, a dimer acid type diamine is a diamine in which two terminal carboxylic acid groups (-COOH) of a dimer acid are substituted with a primary aminomethyl group (-CH ₂ --NH ₂ ) or an amino group (-NH ₂ ). It means a diamine. Dimer acid is a known dibasic acid obtained by intermolecular polymerization reaction of unsaturated fatty acids, and its industrial manufacturing process is almost standardized in the industry. It can be obtained by dimerization using etc. Industrially obtained dimer acids are mainly composed of dibasic acids with 36 carbon atoms obtained by dimerizing unsaturated fatty acids with 18 carbon atoms such as oleic acid and linoleic acid, but depending on the degree of purification, , any amount of monomer acid (18 carbon atoms), trimer acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. In the present invention, it is preferable to use a dimer acid whose content of dimer acid has been increased to 90% by weight or more by molecular distillation. Further, although double bonds remain after the dimerization reaction, in the present invention, dimer acids also include those whose degree of unsaturation has been reduced by further hydrogenation reaction.

A feature of dimer acid type diamines is that they can impart properties derived from the dimer acid skeleton to polyimide. That is, since the dimer acid type diamine is a large aliphatic molecule with a molecular weight of approximately 560 to 620, it is possible to increase the molar volume of the molecule and relatively reduce the number of polar groups in polyimide. It is thought that such characteristics of the dimer acid type diamine contribute to improving the dielectric properties by reducing the dielectric constant and the dielectric loss tangent while suppressing a decrease in the heat resistance of polyimide. In addition, since it has two freely movable hydrophobic chains with 7 to 9 carbon atoms and two chain-like aliphatic amino groups with a length close to 18 carbon atoms, it not only gives polyimide flexibility, but also Since polyimide can be made to have an asymmetrical chemical structure or a non-planar chemical structure, it is thought that it is possible to lower the dielectric constant and dielectric loss tangent of polyimide.

Dimer acid diamines are commercially available, such as PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), PRIAMINE 1075 (trade name) manufactured by Croda Japan, and Versamine 551 (trade name) manufactured by Cognis Japan. ), Versamine 552 (trade name), etc.

In addition, the thermoplastic polyimide forming the adhesive layer contains diamine residues derived from at least one diamine compound selected from the diamine compounds represented by the following general formulas (B1) to (B7), and the entire diamine component. The total content is preferably in the range of 1 to 50 mole parts, and more preferably in the range of 1 to 20 mole parts, per 100 mole parts. Since the diamine compounds represented by the general formulas (B1) to (B7) have a flexible molecular structure, by using at least one diamine compound selected from these in an amount within the above range, polyimide molecules can be formed. It can improve chain flexibility and impart thermoplasticity. If the total amount of diamines (B1) to diamines (B7) exceeds 50 parts by mole based on 100 parts by mole of all diamine components, the solvent solubility of the polyimide may decrease, and if it is less than 1 part by mole, the polyimide The flexibility may be insufficient and the workability at high temperatures may be reduced.

In formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents -O-, -S-, -CO- , -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, and n ₁ is independently Indicates an integer from 0 to 4. However, from equation (B3), those that overlap with equation (B2) are excluded, and from equation (B5), those that overlap with equation (B4) are excluded.
In addition, in formulas (B1) to (B7), the hydrogen atoms in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (here, R ₂ and R ₃ are independently alkyl (means any substituent such as a group).

The diamine represented by formula (B1) (hereinafter sometimes referred to as "diamine (B1)") is an aromatic diamine having two benzene rings. This diamine (B1) has an amino group directly connected to at least one benzene ring and a divalent linking group A in the meta position, which increases the degree of freedom of the polyimide molecular chain and has high flexibility. It is thought that this contributes to improving the flexibility of polyimide molecular chains. Therefore, the use of diamine (B1) increases the thermoplasticity of polyimide. Here, as the linking group A, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -CO-, -SO ₂ -, -S-, and -COO- are preferable.

Examples of the diamine (B1) include 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, and 3,3-diaminodiphenyl ether. , 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, (3,3'-bisamino ) diphenylamine, etc.

The diamine represented by formula (B2) (hereinafter sometimes referred to as "diamine (B2)") is an aromatic diamine having three benzene rings. This diamine (B2) has an amino group directly connected to at least one benzene ring and a divalent linking group A in the meta position, which increases the degree of freedom of the polyimide molecular chain and has high flexibility. It is thought that this contributes to improving the flexibility of polyimide molecular chains. Therefore, the use of diamine (B2) increases the thermoplasticity of polyimide. Here, the linking group A is preferably -O-.

Examples of the diamine (B2) include 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-aminophenoxy)phenoxy]benzenamine, 3-[3-(4-aminophenoxy)phenoxy] Examples include benzeneamine and the like.

The diamine represented by formula (B3) (hereinafter sometimes referred to as "diamine (B3)") is an aromatic diamine having three benzene rings. This diamine (B3) has two divalent linking groups A that are directly connected to one benzene ring and are located in the meta position of each other, which increases the degree of freedom of the polyimide molecular chain and has high flexibility. It is thought that this contributes to improving the flexibility of polyimide molecular chains. Therefore, the use of diamine (B3) increases the thermoplasticity of polyimide. Here, the linking group A is preferably -O-.

Examples of the diamine (B3) 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 and the like.

The diamine represented by formula (B4) (hereinafter sometimes referred to as "diamine (B4)") is an aromatic diamine having four benzene rings. This diamine (B4) has high flexibility because the amino group directly connected to at least one benzene ring and the divalent linking group A are in the meta position, and it can improve the flexibility of the polyimide molecular chain. It is thought that this contributes. Therefore, the use of diamine (B4) increases the thermoplasticity of polyimide. Here, as the linking group A, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, and -CONH- are preferable.

Diamines (B4) include bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]ether, bis Examples include [4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)]benzophenone, and bis[4,4'-(3-aminophenoxy)]benzanilide.

The diamine represented by formula (B5) (hereinafter sometimes referred to as "diamine (B5)") is an aromatic diamine having four benzene rings. This diamine (B5) has two divalent linking groups A that are directly connected to at least one benzene ring and are located in meta positions, so that the degree of freedom of the polyimide molecular chain increases and it has high flexibility. It is thought that this contributes to improving the flexibility of polyimide molecular chains. Therefore, the use of diamine (B5) increases the thermoplasticity of polyimide. Here, the linking group A is preferably -O-.

Examples of the diamine (B5) include 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, etc. .

The diamine represented by formula (B6) (hereinafter sometimes referred to as "diamine (B6)") is an aromatic diamine having four benzene rings. This diamine (B6) has high flexibility because it has at least two ether bonds, and is thought to contribute to improving the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B6) increases the thermoplasticity of polyimide. Here, as the linking group A, -C(CH ₃ ) ₂ -, -O-, -SO ₂ -, and -CO- are preferable.

Examples of the diamine (B6) include 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), bis[4-(4-aminophenoxy)phenyl]ether (BAPE), and bis[4-aminophenoxy)phenyl]ether (BAPE). Examples include -(4-aminophenoxy)phenyl]sulfone (BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), and the like.

The diamine represented by formula (B7) (hereinafter sometimes referred to as "diamine (B7)") is an aromatic diamine having four benzene rings. Since this diamine (B7) has divalent linking groups A with high flexibility on both sides of the diphenyl skeleton, it is thought that it contributes to improving the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B7) increases the thermoplasticity of polyimide. Here, the linking group A is preferably -O-.

Examples of the diamine (B7) include bis[4-(3-aminophenoxy)]biphenyl, bis[4-(4-aminophenoxy)]biphenyl, and the like.

The thermoplastic polyimide forming the adhesive layer may contain diamine residues derived from diamine compounds other than the dimer acid type diamine and diamines (B1) to (B7), as long as the effects of the invention are not impaired. Diamine residues derived from diamine compounds other than the dimer acid type diamine and diamines (B1) to (B7) are used in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer in the above-mentioned insulating resin layer. Residues of those exemplified as diamine compounds can be mentioned.

In the thermoplastic polyimide forming the adhesive layer, select the types of the above-mentioned tetracarboxylic acid residues and diamine residues, and the respective molar ratios when applying two or more types of tetracarboxylic acid residues or diamine residues. Accordingly, the thermal expansion coefficient, tensile modulus, glass transition temperature, etc. can be controlled. Furthermore, when the thermoplastic polyimide has a plurality of polyimide structural units, they may exist as blocks or randomly, but it is preferable that they exist randomly.

The imide group concentration of the thermoplastic polyimide is preferably 33% by weight or less. Here, "imide group concentration" means the value obtained by dividing the molecular weight of the imide group (-(CO) ₂ -N-) in polyimide by the molecular weight of the entire polyimide structure. When the imide group concentration exceeds 33% by weight, the molecular weight of the resin itself decreases, and the low hygroscopicity also deteriorates due to the increase in polar groups. In this embodiment, by controlling the orientation of molecules in thermoplastic polyimide by selecting a combination of the diamine compounds described above, an increase in CTE due to a decrease in imide group concentration is suppressed, and low hygroscopicity is ensured. are doing. Further, if the hygroscopicity of polyimide becomes high, it becomes a factor of deterioration of the dielectric properties of the polyimide film, so ensuring low hygroscopicity is preferable because it can prevent increases in dielectric constant and dielectric loss tangent.

The weight average molecular weight of the thermoplastic polyimide is, for example, preferably within the range of 10,000 to 400,000, more preferably within the range of 20,000 to 350,000. When the weight average molecular weight is less than 10,000, the strength of the adhesive layer decreases and tends to become brittle. On the other hand, if the weight average molecular weight exceeds 400,000, the viscosity increases excessively and defects such as uneven thickness and streaks of the adhesive layer tend to occur during coating operations.

Since the thermoplastic polyimide forming the adhesive layer is interposed between, for example, an insulating resin layer and a wiring layer of a circuit board, it is most preferable to have a completely imidized structure in order to suppress copper diffusion. . However, a part of the polyimide may be an amic acid. The imidization rate was determined to be around 1015 cm ^-1 by measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method using a Fourier transform infrared spectrophotometer (commercial product: JASCO Corporation FT/IR620). It can be calculated from the absorbance of C=O stretching derived from the imide group at 1780 cm ^-1 using the benzene ring absorber as a reference.

(Crosslink formation)
When the thermoplastic polyimide forming the adhesive layer has a ketone group, the ketone group is reacted with the amino group of an amino compound having at least two primary amino groups as functional groups to form a C=N bond. By doing so, a crosslinked structure can be formed. By forming a crosslinked structure, the heat resistance of the thermoplastic polyimide forming the adhesive layer can be improved. Preferred tetracarboxylic anhydrides for forming a thermoplastic polyimide having a ketone group include, for example, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), and examples of diamine compounds include, for example. , 4,4'-bis(3-aminophenoxy)benzophenone (BABP), and 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene (BABB).

Examples of the amino compounds that can be used to crosslink the thermoplastic polyimide forming the adhesive layer include dihydrazide compounds, aromatic diamines, aliphatic amines, and the like. Among these, dihydrazide compounds are preferred. When a dihydrazide compound is used, the curing time after crosslinking can be shortened compared to when other amino compounds are used. Examples of dihydrazide compounds include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, and maleic acid. Dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoedioic acid dihydrazide, 4,4-bisbenzene dihydrazide, 1,4 -Dihydrazide compounds such as naphthoic acid dihydrazide, 2,6-pyridinedioic acid dihydrazide, and itaconic acid dihydrazide are preferred. The above dihydrazide compounds may be used alone or in combination of two or more.

<Manufacture of adhesive layer>
The thermoplastic polyimide forming the adhesive layer can be produced by reacting the above-mentioned tetracarboxylic dianhydride and a diamine compound in a solvent to generate a polyamic acid, and then ring-closing the polyamic acid by heating. For example, a polyimide precursor can be obtained by dissolving approximately equimolar amounts of tetracarboxylic dianhydride and a diamine compound in an organic solvent, stirring at a temperature within the range of 0 to 100°C for 30 minutes to 24 hours, and causing a polymerization reaction. A polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the amount of the precursor to be produced is within the range of 5 to 50% by weight, preferably within the range of 10 to 40% by weight. Examples of organic solvents used in the polymerization reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2 -butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol and the like. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can also be used in combination. Further, the amount of such an organic solvent to be used is not particularly limited, but it should be adjusted to an amount such that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight. is preferred.

It is usually advantageous to use the synthesized polyamic acid as a reaction solvent solution, but it can be concentrated, diluted, or replaced with another organic solvent if necessary. In addition, polyamic acids generally have excellent solvent solubility, so they are advantageously used. Preferably, the viscosity of the polyamic acid solution is within the range of 500 cps to 100,000 cps. Outside this range, defects such as uneven thickness and streaks are likely to occur in the film during coating operations using a coater or the like.

The method of imidizing polyamic acid to form thermoplastic polyimide is not particularly limited, and for example, heat treatment such as heating in the above solvent at a temperature in the range of 80 to 400 ° C. for 1 to 24 hours is suitable. will be adopted.

When crosslinking the thermoplastic polyimide obtained as described above, the above amino compound is added to a resin solution containing the thermoplastic polyimide having a ketone group, and the ketone group in the thermoplastic polyimide and the amino compound are combined. A condensation reaction is performed with a primary amino group. This condensation reaction causes the resin solution to harden into a cured product. In this case, the amount of the amino compound added is a total of 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, more preferably 0.005 mol to 1.2 mol, and more preferably The amino compound can be added in an amount of 0.03 mole to 0.9 mole, most preferably 0.04 mole to 0.5 mole. If the amount of the amino compound added is such that the total amount of primary amino groups is less than 0.004 mol per 1 mol of ketone groups, crosslinking of the thermoplastic polyimide by the amino compound will not be sufficient. Heat resistance tends to be difficult to develop in the adhesive layer, and if the amount of the amino compound added exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic agent and tends to reduce the heat resistance of the adhesive layer.

Conditions for the condensation reaction for forming crosslinks are not particularly limited as long as the ketone group in the thermoplastic polyimide reacts with the primary amino group of the amino compound to form an imine bond (C=N bond). The temperature of the heating condensation is set to 120° C., for example, in order to release water produced by condensation to the outside of the system, or to simplify the condensation process when performing a heating condensation reaction after synthesizing the thermoplastic polyimide. The temperature range is preferably from 140 to 200°C, more preferably from 140 to 200°C. The reaction time is preferably about 30 minutes to 24 hours, and the end point of the reaction can be determined, for example, by measuring the infrared absorption spectrum using a Fourier transform infrared spectrophotometer (commercial product: JASCO Corporation FT/IR620). This can be confirmed by the decrease or disappearance of the absorption peak derived from the ketone group in the polyimide resin around ⁻¹ and the appearance of the absorption peak derived from the imine group around 1635 cm ⁻¹ .

Thermal condensation of the ketone group of the thermoplastic polyimide and the primary amino group of the amino compound can be carried out by, for example, (a) a method of adding an amino compound and heating subsequent to the synthesis (imidization) of the thermoplastic polyimide; b) A method in which an excess amount of an amino compound is charged in advance as a diamine component, and subsequent to the synthesis (imidization) of the thermoplastic polyimide, the thermoplastic polyimide is heated together with the remaining amino compound that does not participate in the imidization or amidation, or (c) After processing a thermoplastic polyimide composition (adhesive polyimide resin composition described below) to which an amino compound has been added into a predetermined shape (for example, after applying it to an arbitrary base material or forming it into a film) ), etc.

(thickness of adhesive layer)
The thickness of the adhesive layer is, for example, preferably in the range of 0.1 to 100 μm, more preferably in the range of 0.3 to 50 μm. In the three-layer metal-clad laminate of this embodiment, if the thickness of the adhesive layer is less than the above-mentioned lower limit, problems may occur, such as insufficient adhesion. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit, problems such as decreased dimensional stability will occur. Further, from the viewpoint of lowering the dielectric constant and dielectric loss tangent of the entire insulating layer, which is a laminate of the insulating resin layer and the adhesive layer, the thickness of the adhesive layer is preferably 3 μm or more.

(CTE of adhesive layer)
The thermoplastic polyimide forming the adhesive layer has high thermal expansion, and has a CTE of preferably 35 ppm/K or more, more preferably 35 ppm/K or more and 80 ppm/K or less, and even more preferably 35 ppm/K or more and 70 ppm/K. It is within the range of K or less. A polyimide layer having a desired CTE can be obtained by appropriately changing the combination of raw materials used, the thickness, and drying/curing conditions.

(Dielectric loss tangent of adhesive layer)
When the adhesive layer is applied to a circuit board, for example, in order to suppress deterioration of dielectric loss, the dielectric loss tangent (Tan δ) at 10 GHz is 0.004 or less, more preferably in the range of 0.001 or more and 0.004 or less. More preferably, it is in the range of 0.002 or more and 0.003 or less. If the dielectric loss tangent of the adhesive layer exceeds 0.004 at 10 GHz, problems such as electrical signal loss on the high frequency signal transmission path are likely to occur when used in circuit boards such as FPCs. On the other hand, the lower limit of the dielectric loss tangent of the adhesive layer at 10 GHz is not particularly limited.

(Permittivity of adhesive layer)
In order to ensure impedance matching when the adhesive layer is applied as an insulating layer of a circuit board, for example, it is preferable that the dielectric constant at 10 GHz is 4.0 or less. If the dielectric constant of the adhesive layer exceeds 4.0 at 10 GHz, the dielectric loss of the adhesive layer will deteriorate when used on circuit boards such as FPCs, resulting in inconveniences such as electrical signal loss on the high-frequency signal transmission path. becomes more likely to occur.

(filler)
The adhesive layer may contain a filler, if necessary. Examples of fillers include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and metal salts of organic phosphinic acids. These can be used alone or in combination of two or more.

<Metal layer>
The material of the metal layer in the metal-clad laminate of this embodiment is not particularly limited, but examples include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, and tantalum. , titanium, lead, magnesium, manganese, and alloys thereof. Among these, copper or copper alloy is particularly preferred. Note that the material of the wiring layer in the circuit board of this embodiment, which will be described later, is also the same as that of the metal layer.

The thickness of the metal layer is not particularly limited, but for example, when copper foil is used as the metal layer, it is preferably 35 μm or less, more preferably within the range of 5 to 25 μm. From the viewpoint of production stability and handling properties, the lower limit of the thickness of the copper foil is preferably 5 μm. In addition, when using copper foil, rolled copper foil or electrolytic copper foil may be used. Moreover, as the copper foil, commercially available copper foil can be used.

(rust prevention treatment)
When copper foil is used as the metal layer in this embodiment, the copper foil is formed on the base copper foil and the surface of the base copper foil on the side where the adhesive layer (or insulating resin layer) is formed. It is preferable to include a rust-proofing layer. The rust prevention treatment can suppress a decrease in the adhesive strength between the copper foil and the adhesive layer during wiring processing of the metal-clad laminate, and suppress a decrease in resistance to chemicals caused by etching. The base material copper foil may be either an electrolytic copper foil or a rolled copper foil. The thickness of such base material copper foil is not particularly limited as long as it is within the thickness range of copper foil used for general copper-clad laminates, but from the viewpoint of flexibility of copper-clad laminates, it is recommended that the thickness be 70 μm or less. It is preferable that there be. If the thickness exceeds 70 μm, it is not preferable because the uses of the resulting copper-clad laminate will be limited. Further, when the copper-clad laminate is used as a flexible copper-clad laminate, the thickness of the base copper foil is preferably in the range of 5 to 35 μm. If the thickness of the base material copper foil is less than 5 μm, wrinkles etc. tend to occur during manufacturing, making it expensive to manufacture a thin copper foil. On the other hand, if the thickness exceeds 35 μm, the resulting copper-clad laminate When used, there is a tendency for IC mounting boards, etc. that drive liquid crystal displays, which are the display units of personal computers, mobile phones, and personal digital assistants (PDAs), to be insufficiently made thinner and smaller.

From the viewpoint of improving the adhesive strength (peel strength) and chemical resistance between the base material copper foil and the copper foil and the adhesive layer, it is preferable to use one whose surface has been roughened. The ten-point average roughness (Rz) of the base material copper foil is preferably 1.5 μm or less, for example, from the above viewpoint and from the viewpoint of flexibility and conductor loss reduction of the resulting copper-clad laminate; More preferably, the thickness is in the range of .1 to 1.0 μm.

The antirust treatment layer according to the present invention is a layer having antirust properties that is formed on the surface of the base material copper foil on the side where the adhesive layer is formed. In the present invention, by forming such a rust prevention treatment layer on the base copper foil, sufficient rust prevention properties are imparted to the base copper foil, and the adhesive strength between the adhesive layer and the copper foil is improved. It becomes possible to improve the The thickness of such a rust-proofing layer is preferably in the range of, for example, 10 to 50 nm. If the thickness is less than the above lower limit, the surface of the base copper foil will not be uniformly covered and it will be difficult to obtain a sufficient rust prevention effect.On the other hand, if the thickness exceeds the above upper limit, the rust prevention treatment layer will not dissolve in the copper etching solution. The properties (etchability) tend to be insufficient.

Preferably, the anticorrosive layer includes a zinc-containing plating layer and a chromate layer. Such a treatment layer can be formed by plating the surface of the base material copper foil using a plating solution containing a zinc compound to form a zinc plating treatment layer, and further providing a chromate treatment layer to provide protection. The rust effect and adhesion to the adhesive layer can be further improved. The chromate treatment layer can be formed by subjecting the surface of the rust prevention treatment layer to immersion or electrolytic chromate treatment using a chromate treatment agent containing chromium oxide or the like.

Further, it is preferable that the zinc content in the anticorrosive layer is 0.01 mg/dm ² or more. If the zinc content is less than the above-mentioned lower limit, the solubility (etchability) of the rust-preventing layer in the copper etching solution will be insufficient, and the rust-preventing layer will deteriorate due to thermal deterioration during the production of the copper-clad laminate, causing the adhesive layer to deteriorate. The adhesive strength with copper foil tends to be insufficient. In addition, from the viewpoint of further improving the etching properties of the rust prevention treatment layer and the adhesive strength between the adhesive layer and the copper foil, the zinc content is preferably in the range of 0.01 to 1.5 mg/ ^dm2 . More preferred.

Furthermore, the antirust treatment layer may contain a metal other than zinc. Examples of metals other than zinc include nickel, cobalt, molybdenum, and the like. For example, it is preferable that the nickel content in the anticorrosive layer is 0.1 mg/dm ² or more. If the nickel content is less than the lower limit, the rust prevention effect on the surface of the copper foil will not be sufficient, and the surface of the copper foil will tend to discolor after heating or in a high temperature or high humidity environment. Further, from the viewpoint of sufficiently preventing copper from diffusing from the base copper foil into the rust prevention treatment layer and adhesive layer, it is more preferable that the nickel content is in the range of 0.1 to 3 mg/ ^dm2 . .

Nickel is either completely solid with respect to copper and can create an alloy state, or nickel easily diffuses into copper and can easily create an alloy state. In such a state, the electrical resistance is higher than that of copper alone, or in other words, the electrical conductivity is lower. For this reason, if a large amount of nickel is contained in the anti-rust layer, the resistance of copper alloyed with nickel will increase. As a result, loss during signal transmission increases due to increased resistance of the signal wiring due to the skin effect. From this point of view, when the copper-clad laminate of this embodiment is used in a process such as a circuit board that performs high frequency transmission of 10 GHz, it is preferable to suppress the amount of nickel to 0.01 mg/dm ² or less. .

When suppressing the amount of nickel in the rust preventive layer to 0.01 mg/dm ² or less, it is preferable that the rust preventive layer contains at least cobalt and molybdenum. Such a rust prevention treatment layer contains nickel of 0.01 mg/dm ² or less, cobalt of 0.01 to 0.5 mg/dm ² , and molybdenum of 0.01 to 0.5 mg/dm ² . It is preferable that the total amount of cobalt element and molybdenum element (Co+Mo) be within the range of 0.1 to 0.7 mg/dm ² . By keeping it within this range, it is possible to suppress the etching residue on the resin part between the wirings during wiring processing of the copper-clad laminate, suppress the decrease in resistance to chemicals caused by etching, and improve the adhesive strength and strength between the copper foil and the resin. The decline in long-term reliability can be suppressed.

In addition to the above-mentioned anti-rust treatment, the copper foil used in the copper-clad laminate of this embodiment is treated with siding, aluminum alcoholate, aluminum chelate, silane, etc. on the surface of the copper foil for the purpose of improving adhesive strength. Surface treatment with a coupling agent or the like may be performed.

<Method for manufacturing metal-clad laminates>
Metal-clad laminates are produced by, for example, preparing a resin film in which an adhesive layer and an insulating resin layer are laminated, sputtering metal to form a seed layer on the adhesive layer side, and then forming a metal layer by, for example, plating. It may be prepared by:

Metal-clad laminates are prepared by preparing a resin film in which an adhesive layer and an insulating resin layer are laminated, and then laminating a metal foil such as copper foil on the adhesive layer side using a method such as thermocompression bonding. It's okay.

Furthermore, metal-clad laminates are produced by casting a coating solution to form an adhesive layer on metal foil such as copper foil, drying it to form a coating film, and forming an insulating resin layer on top of the coating film. It may also be prepared by casting a coating liquid for coating, drying it to form a coating film, and then heat-treating the film all at once. In this case, as a coating liquid for forming the adhesive layer, an adhesive polyimide resin composition (described later) or a polyamic acid solution which is a precursor of thermoplastic polyimide forming the adhesive layer can be used. Further, the thermoplastic polyimide forming the adhesive layer may be crosslinked by the above method.

[Circuit board]
The metal-clad laminate of this embodiment is mainly useful as a material for circuit boards such as FPCs and rigid-flex circuit boards. That is, an FPC according to an embodiment of the present invention can be manufactured by processing the metal layer of the metal-clad laminate according to the present embodiment into a pattern by a conventional method to form a wiring layer.

[Adhesive sheet]
The adhesive sheet of this embodiment includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. This is an adhesive sheet for forming the adhesive layer in a metal-clad laminate having the following. This adhesive sheet is made by forming the thermoplastic polyimide that forms the adhesive layer described above into a sheet shape. That is, the thermoplastic polyimide forming the adhesive sheet contains a predetermined amount of tetracarboxylic acid residue and diamine residue, similar to the adhesive layer described above.

The adhesive sheet may be laminated on any base material such as a copper foil, a glass plate, a polyimide film, a polyamide film, or a polyester film. The thickness, thermal expansion coefficient, dielectric loss tangent, dielectric constant, etc. of the adhesive sheet are similar to those of the adhesive layer described above. Further, the adhesive sheet can contain optional components such as fillers.

As an aspect of the manufacturing method of the adhesive sheet of this embodiment, for example, [1] A solution of polyamic acid is applied to a supporting base material, dried, heat-treated to imidize, and then peeled off from the supporting base material to form an adhesive sheet. [2] A method of manufacturing an adhesive sheet by coating and drying a polyamic acid solution on a supporting base material, peeling off a polyamic acid gel film from the supporting base material, and heat-treating it to imidize it. 3] A method of manufacturing an adhesive sheet by applying a solution of an adhesive polyimide resin composition (described later) to a supporting base material, drying it, and then peeling it off from the supporting base material. Note that the thermoplastic polyimide constituting the adhesive sheet may be crosslinked by the above method.

The method for applying the polyimide solution (or polyamic acid solution) onto the support substrate is not particularly limited, and can be applied using a comma, die, knife, lip, or other coater. The adhesive sheet to be manufactured is preferably formed by applying a polyimide solution that has been imidized in a polyamic acid solution onto a supporting base material and drying it. Since the polyimide of this embodiment is solvent-soluble, it is advantageous that the polyamic acid can be imidized in a solution state and used as it is as a polyimide coating solution.

The adhesive sheet obtained in the above manner has excellent flexibility and dielectric properties (low dielectric constant and low dielectric loss tangent) when used to form an adhesive layer for a circuit board, such as FPC, It has desirable properties as an adhesive layer for rigid-flex circuit boards and the like.

[Adhesive polyimide resin composition]
The adhesive polyimide resin composition of the present embodiment includes an insulating resin layer, an adhesive layer laminated on at least one side of the insulating resin layer, and a metal layer laminated on the insulating resin layer via the adhesive layer. This is for forming the adhesive layer in a metal-clad laminate having a layer. The adhesive polyimide resin composition contains a polyimide containing a tetracarboxylic acid residue and a diamine residue, and the two terminal carboxylic acid groups of the dimer acid account for 1 part by mole of the diamine residue. 50 mole parts or more, for example, 50 mole parts or more and 99 mole parts or less, preferably 80 mole parts or more, of a diamine residue derived from a dimer acid type diamine substituted with an aminomethyl group or an amino group of For example, the tetracarboxylic anhydride represented by the general formula (1) and/or (2) is contained within the range of 80 mole parts or more and 99 mole parts or less, and per 100 mole parts of the tetracarboxylic acid residue. Contains 90 mole parts or more of tetracarboxylic acid residues derived from compounds.

In addition, the adhesive polyimide resin composition contains 1 mol part or more and 50 mol parts or more of diamine residues derived from at least one diamine compound selected from the diamine compounds represented by the above general formulas (B1) to (B7). The content is preferably within the following range.

The adhesive polyimide resin composition of this embodiment is solvent soluble and can contain an organic solvent as an optional component. Preferred organic solvents include, for example, N,N-dimethylformamide, N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethylsulfoxide, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, Examples include diglyme, triglyme, etc. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can also be used in combination.

The adhesive polyimide resin composition of the present embodiment includes, as further optional components, an amino compound having at least two primary amino groups as functional groups used for the above-mentioned crosslinking, an inorganic filler, a plasticizer, and an epoxy resin composition. Other resin components such as resins, curing accelerators, coupling agents, fillers, pigments, solvents, flame retardants, etc. can be blended as appropriate.

The adhesive polyimide resin composition obtained as described above has excellent flexibility and dielectric properties (low dielectric constant and low dielectric loss tangent) when used to form an adhesive layer or adhesive sheet. For example, it can be preferably applied as a material for forming an adhesive layer of FPC, rigid/flex circuit boards, etc.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, in the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of coefficient of thermal expansion (CTE)]
A polyimide film with a size of 3 mm x 20 mm was heated from 30° C. to 300° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Bruker, trade name: 4000SA). After further 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 surface roughness of copper foil]
The surface roughness of the copper foil was measured using AFM (manufactured by Bruker AXS, trade name: Dimension Icon type SPM), probe (manufactured by Bruker AXS, trade name: TESPA (NCHV), tip radius of curvature 10 nm, Using a spring constant of 42 N/m), measurement was performed in a tapping mode on an area of 80 μm x 80 μm on the surface of the copper foil, and the ten-point average roughness (Rzjis) was determined.

[Measurement of metallic elements on the surface of copper foil treated with metal deposition]
After masking the back side of the analysis surface of the copper foil, dissolve the analysis surface with 1N nitric acid, adjust the volume to 100 mL, and then measure using PerkinElmer's inductively coupled plasma emission spectrometer (ICP-AES) Optima 4300. did.

[Warpage evaluation method]
The warpage was evaluated using the following method. A 10 cm x 10 cm film was placed, and the average height of the four corners of the film was measured. If it was 10 mm or less, it was rated "good" and if it exceeded 10 mm, it was rated "unsatisfactory."

[Measurement of dielectric constant (Dk) and dielectric loss tangent (Df)]
The permittivity and dielectric loss tangent were measured using a cavity resonator perturbation method permittivity evaluation device (manufactured by Agilent, trade name: Vector Network Analyzer E8363C) and a split post dielectric resonator (SPDR resonator), using a resin sheet at a frequency of 10 GHz. (or an insulating layer in which a resin sheet is laminated on an insulating resin layer), the dielectric constant and dielectric loss tangent were measured. The resin sheet (or the insulating layer in which the resin sheet is laminated on the insulating resin layer) used in the measurement was left for 24 hours at a temperature of 24 to 26°C and a humidity of 45 to 55%.

[Laser processability evaluation method]
Laser processability was evaluated using the following method. UV-YAG, 3rd harmonic 355nm laser light is irradiated with a frequency of 60kHz and an intensity of 1.0W to process the via with a bottom, and if there is no gouging or undercut in the adhesive layer, it is judged as "Acceptable". Those in which gouges or undercuts occurred in the agent layer were rated as "unacceptable."

[Measurement of peel strength]
Peel strength was measured using the following method. Using a tensile tester (Strograph VE, manufactured by Toyo Seiki Seisakusho), the peel strength was measured when an insulating resin layer with a test piece width of 5 mm was pulled in the 90° direction of the adhesive layer at a speed of 50 mm/min. In addition, a peel strength of 0.9 kN/m or more is considered "good", a peel strength of 0.4 kN/m or more and less than 0.9 kN/m is "acceptable", and a peel strength of less than 0.4 kN/m is "unacceptable". evaluated.

The abbreviations used in this example represent the following compounds.
BTDA: 3,3',4,4'-benzophenonetetracarboxylic dianhydride BPDA: 3,3',4,4'-diphenyltetracarboxylic dianhydride 6FDA: 4,4'-(hexafluoroisopropylidene ) diphthalic anhydride BPADA: 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride PMDA: pyromellitic dianhydride APB: 1,3-bis(3-aminophenoxy) ) Benzene BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane DDA: Aliphatic diamine with 36 carbon atoms (manufactured by Croda Japan Co., Ltd., trade name: PRIAMINE 1074, amine value: 210 mgKOH/g, cyclic mixture of dimer diamines with structure and chain structure, content of dimer component: 95% by weight or more)
m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl ODPA: 4,4'-oxydiphthalic anhydride (also known as 5,5'-oxybis-1,3-isobenzofurandione)
N-12: Dodecanedioic acid dihydrazide NMP: N-methyl-2-pyrrolidone DMAc: N,N-dimethylacetamide

(Synthesis example 1)
<Preparation of resin solution for adhesive layer>
A 1000 ml separable flask was charged with 56.18 g of BTDA (0.174 mol), 93.82 g of DDA (0.176 mol), 210 g of NMP, and 140 g of xylene, and mixed well at 40°C for 1 hour. A polyamic acid solution was prepared. Polyimide solution 1 (solid content: 30% by weight, viscosity: 5,100 cps, weight average molecular weight ;66,100) was prepared.

(Synthesis examples 2 to 10)
<Preparation of resin solution for adhesive layer>
Polyimide solutions 2 to 10 were prepared in the same manner as in Synthesis Example 1, except that the raw material compositions shown in Table 1 were used.

(Synthesis example 11)
<Preparation of resin solution for adhesive layer>
1.1 g of N-12 (0.004 mol) was blended with 100 g (30 g as solid content) of polyimide solution 1 prepared in Synthesis Example 1, and diluted by adding 0.1 g of NMP and 10 g of xylene. Polyimide solution 11 was prepared by further stirring for 1 hour.

(Synthesis Examples 12 to 17)
<Preparation of resin solution for adhesive layer>
Polyimide solutions 12 to 17 were prepared in the same manner as in Synthesis Example 11, except that polyimide solutions 5 to 10 shown in Table 2 were used.

(Synthesis example 18)
<Preparation of polyimide film for insulating resin layer>
Under a nitrogen stream, 2.196 g of DDA (0.0041 mol), 16.367 g of m-TB (0.0771 mol) and 212.5 g of DMAc were placed in a 300 ml separable flask and stirred at room temperature. and dissolved. Next, after adding 4.776 g of BPDA (0.0162 mol) and 14.161 g of PMDA (0.0649 mol), a polymerization reaction was carried out by continuing stirring at room temperature for 3 hours. ;26,000 cps) was prepared.

Polyamic acid solution P was uniformly applied to a copper foil (surface roughness Rz: 2.1 μm) so that the thickness after curing would be about 25 μm, and then heated and dried at 120° C. to remove the solvent. Furthermore, stepwise heat treatment was performed from 120° C. to 360° C. to complete imidization, and a metal clad laminate P was prepared. Regarding the metal-clad laminate P, the copper foil was etched away using a ferric chloride aqueous solution to prepare a polyimide film P (CTE: 20 ppm/K, Dk: 2.95, Df: 0.0041).

(Preparation example 1)
<Preparation of resin sheet for adhesive layer>
A resin sheet 1a (thickness: 25 μm) was prepared by applying polyimide solution 1 to one side of a release-treated PET film, drying it at 80° C. for 15 minutes, and then peeling it off. Table 3 shows the dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet 1a.

(Preparation examples 2 to 7)
<Preparation of resin sheet for adhesive layer>
Using polyimide solution 1, resin sheets 1b to 1g were prepared in the same manner as in Preparation Example 1, with different thicknesses of the resin sheets. Table 3 shows the dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheets 1b to 1g.

(Preparation examples 8 to 16)
<Preparation of resin sheet for adhesive layer>
Resin sheets 2a to 10a having a thickness of 25 μm were prepared in the same manner as in Preparation Example 1, except that the polyimide solutions shown in Table 4 were used. Table 4 shows the dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheets 2a to 10a.

(Preparation example 17)
<Preparation of copper foil with anti-rust treatment>
An electrolytic copper foil (thickness: 12 μm, surface roughness Rz in MD direction (Machine Direction; flow direction of the long copper foil) on the resin layer side: 0.3 μm) was prepared. After roughening the surface of this copper foil, it is plated with a predetermined amount of cobalt and molybdenum (metal deposition treatment), and then sequentially subjected to zinc plating and chromate treatment. 01 mg/dm ² or less, Co: 0.23 mg/dm ² , Mo: 0.36 mg/dm ² , Zn: 0.11 mg/dm ² , Cr: 0.14 mg/dm ² ).

[Example 1]
Resin sheet 1a (thickness: 25 μm, Dk: 2.4, Df: 0.0020) is placed on copper foil 1 (surface roughness Rz: 0.3 μm), and polyimide film 1 (Toray manufactured by DuPont, product name: Kapton EN-S, thickness: 25 μm, CTE: 16 ppm/K, Dk: 3.79, Df: 0.0126) at a temperature of 170°C and a pressure of 0.85 MPa. Copper-clad laminate 1 was prepared by vacuum laminating for 1 minute and then heating in an oven at 160° C. for 1 hour. Table 5 shows the evaluation results of the copper-clad laminate 1.

[Example 2]
Copper-clad laminate 2 was prepared in the same manner as in Example 1, except that 1 g of resin sheet (thickness: 50 μm, Dk: 2.4, Df: 0.0020) was used in place of resin sheet 1a. Table 5 shows the evaluation results of the copper-clad laminate 2.

[Example 3]
1 g of resin sheet was used instead of resin sheet 1a, and liquid crystal polymer film 3 (manufactured by Kuraray Co., Ltd., trade name: CT-Z, thickness: 50 μm, CTE: 18 ppm/K, Dk; Copper-clad laminate 3 was prepared in the same manner as in Example 1, except that 3.40, Df: 0.0022) was used. Table 5 shows the evaluation results of the copper-clad laminate 3.

The results of Examples 1 to 3 are summarized in Table 5.

[Example 4]
Polyimide solution 1 was applied to one side of polyimide film P prepared in Synthesis Example 18, and dried at 80° C. for 15 minutes to prepare insulating film 4 (adhesive layer thickness: 3 μm). With the adhesive layer side of the insulating film 4 superimposed on the rust-prevention treated side of the copper foil 1, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then in an oven at a temperature of 160°C. The copper clad laminate 4 was prepared by heating for 1 hour. Table 6 shows the evaluation results of the copper-clad laminate 4.

[Example 5]
A copper-clad laminate 5 was prepared in the same manner as in Example 4 except that the thickness of the adhesive layer was 1 μm. Table 6 shows the evaluation results of the copper-clad laminate 5.

[Example 6]
A copper-clad laminate 6 was prepared in the same manner as in Example 4 except that the thickness of the adhesive layer was 0.3 μm. Table 6 shows the evaluation results of the copper-clad laminate 6.

The results of Examples 4 to 6 are summarized in Table 6.

[Example 7]
Polyimide solution 1 was applied to the polyimide film surface of the copper-clad laminate 4 prepared in Example 4, and dried at 80°C for 15 minutes to make the adhesive layer 3 μm thick. With the treated surface stacked on the adhesive layer surface, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then heated in an oven at a temperature of 160°C for a time of 1 hour to form a copper clad layer. Laminated board 7 was prepared. Table 7 shows the evaluation results for copper-clad laminate 7.

[Example 8]
A copper-clad laminate 8 was prepared in the same manner as in Example 7 except that the thickness of the adhesive layer was 1 μm. Table 7 shows the evaluation results of the copper-clad laminate 8.

[Example 9]
A copper-clad laminate 9 was prepared in the same manner as in Example 7 except that the thickness of the adhesive layer was 0.3 μm. Table 7 shows the evaluation results of the copper-clad laminate 9.

The results of Examples 7 to 9 are summarized in Table 7.

[Example 10]
Polyimide solution 1 was applied to one side of polyimide film 1 and dried at 80° C. for 15 minutes to prepare insulating film 5 (adhesive layer thickness: 12 μm). With the adhesive layer side of the insulating film 5 superimposed on the anti-corrosion treated side of the copper foil 1, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then in an oven at a temperature of 160°C. The copper clad laminate 10 was prepared by heating for 1 hour. Table 8 shows the evaluation results of the copper-clad laminate 10.

[Example 11]
Polyimide solution 1 was applied to the antirust-treated side of copper foil 1 and dried at 80° C. for 15 minutes to prepare copper foil-coated film 6 (adhesive layer thickness: 5 μm). The adhesive layer surface of the copper foil-coated film 6 and the polyimide film 2 (manufactured by DuPont-Toray Co., Ltd., product name: Kapton EN, thickness: 5 μm, CTE: 16 ppm/K, Dk: 3.70, Df: 0.0076) were overlapped. In this state, the copper-clad laminate 11 was prepared by vacuum laminating at a temperature of 170° C., a pressure of 0.85 MPa, and a time of 1 minute, and then heating in an oven at a temperature of 160° C. for a time of 1 hour. Table 8 shows the evaluation results of the copper-clad laminate 11.

[Example 12]
A polyimide solution 13 was applied to the polyimide film surface of the copper-clad laminate 4 prepared in Example 4, and dried at 80° C. for 15 minutes to make the adhesive layer 25 μm thick. With the treated surface stacked on the adhesive layer surface, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then heated in an oven at a temperature of 160°C for a time of 1 hour to form a copper clad layer. A laminate 12 was prepared. Table 8 shows the evaluation results of the copper-clad laminate 12.

[Example 13]
A polyimide solution 16 was applied to the polyimide film surface of the copper-clad laminate 4 prepared in Example 4, and dried at 80° C. for 15 minutes to make the adhesive layer 25 μm thick. With the treated surface stacked on the adhesive layer surface, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then heated in an oven at a temperature of 160°C for a time of 1 hour to form a copper clad layer. A laminate 13 was prepared. Table 8 shows the evaluation results of the copper-clad laminate 13.

(Synthesis Examples 19-21)
<Preparation of resin solution for adhesive layer>
Polyimide solutions 19 to 21 were prepared in the same manner as in Synthesis Example 1, except that the raw material compositions shown in Table 9 were used.

(Preparation examples 18 to 20)
<Preparation of resin sheet for adhesive layer>
Resin sheets 18a to 20a having a thickness of 25 μm were prepared in the same manner as in Production Example 1, except that the polyimide solutions shown in Table 10 were used. Table 10 shows the dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheets 18a to 20a.

(Comparative example 1)
Polyimide solution 19 was applied to one side of polyimide film 1 and dried at 80° C. for 15 minutes to prepare insulating film 7 (adhesive layer thickness: 12 μm). With the adhesive layer side of the insulating film 7 superimposed on the anti-corrosion treated side of the copper foil 1, vacuum lamination was performed at a temperature of 170°C, a pressure of 0.85 MPa, and a time of 1 minute, and then in an oven at a temperature of 160°C. The copper clad laminate 18 was prepared by heating for 1 hour. Table 11 shows the evaluation results of the copper-clad laminate 18.

(Comparative example 2)
A copper-clad laminate 19 was prepared in the same manner as in Comparative Example 1 except that the polyimide solution 20 was used. Table 11 shows the evaluation results of the copper-clad laminate 19.

(Comparative example 3)
A copper-clad laminate 20 was prepared in the same manner as in Comparative Example 1 except that the polyimide solution 21 was used. Table 11 shows the evaluation results of the copper-clad laminate 20.

Although the embodiments of the present invention have been described above in detail for the purpose of illustration, the present invention is not limited to the above embodiments and can be modified in various ways.

Claims (6)

A double-sided metal-clad laminate comprising an insulating resin layer, an adhesive layer laminated on both sides of the insulating resin layer, and a metal layer laminated on both sides of the insulating resin layer via the adhesive layer. hand,
The adhesive layer is a thermoplastic polyimide layer containing thermoplastic polyimide containing a tetracarboxylic acid residue and a diamine residue as a resin component,
The thermoplastic polyimide has a weight average molecular weight within the range of 59,600 to 400,000, and two terminal carboxylic acid groups of the dimer acid are primary aminomethyl based on 100 mole parts of the diamine residue. 1. A double-sided metal-clad laminate containing 50 mole parts or more of a diamine residue derived from a dimer acid type diamine substituted with a group or an amino group. The thermoplastic polyimide contains, based on 100 mole parts of the tetracarboxylic acid residue,
Claim 1, characterized in that it contains a total of 90 mole parts or more of tetracarboxylic acid residues derived from tetracarboxylic acid anhydrides represented by the following general formulas (1) and/or (2). Double-sided metal clad laminate.

[In general formula (1), X represents a single bond or a divalent group selected from the following formula, and in general formula (2), the cyclic moiety represented by Y is a 4-membered ring, a 5-membered ring, It represents forming a cyclic saturated hydrocarbon group selected from a ring, a 6-membered ring, a 7-membered ring, or an 8-membered ring. ]

[In the above formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-O-C(=O)-CH ₃ )-CH ₂ -, but n is Indicates an integer from 1 to 20. ] The thermoplastic polyimide contains, based on 100 mole parts of the diamine residue,
Containing a diamine residue derived from the dimer acid type diamine in a range of 50 mole parts or more and 99 mole parts or less,
A claim containing a diamine residue derived from at least one diamine compound selected from diamine compounds represented by the following general formulas (B1) to (B7) in a range of 1 to 50 mole parts. 2. The double-sided metal-clad laminate according to 1 or 2.

[In formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents -O-, -S-, -CO -, -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, where n ₁ is independent indicates an integer from 0 to 4. However, from equation (B3), those that overlap with equation (B2) are excluded, and from equation (B5), those that overlap with equation (B4) are excluded. ] 3. The double-sided metal-clad laminate according to claim 1, wherein each of the metal layers is made of copper foil, and a surface of the copper foil that comes into contact with the adhesive layer is anticorrosive treated. The surface of the copper foil in contact with the adhesive layer has a rust prevention treatment layer including a zinc-containing plating layer and a chromate treatment layer formed by rust prevention treatment, and the nickel content in the rust prevention treatment layer is 0.01mg/dm ² Below, the cobalt content is 0.01 to 0.5 mg/dm ² Molybdenum content is within the range of 0.01 to 0.5 mg/dm ² and the total amount of cobalt element and molybdenum element (Co+Mo) is 0.1 to 0.7 mg/dm ² The double-sided metal-clad laminate according to claim 4, which is within the range of. A circuit board formed by processing at least one of the metal layers of the double-sided metal-clad laminate according to claim 1 or 2 into wiring.