TW202225276A - Polyimide film, metal-clad laminate, method for producing same and circuit substrate - Google Patents

Abstract

This invention provides a polyimide film, a metal-clad laminate, a metal-clad laminate manufacturing method, and a circuit substrate. It is able to provide a configuration capable of realizing good adhesion at an interface between a polyimide film or a polyimide insulation layer and a bonding sheet in a polyimide film or a metal-clad laminate without deteriorating the dielectric properties. According to a polyimide film or a polyimide insulation layer as a whole, it satisfies: (i) an oxygen permeation coefficient of 2.0 * 10<SP>-18</SP> mol.m/m2.s.Pa or less; (ii) a thermal expansion coefficient in the range of 10 to 30 ppm/K; (iii) a dielectric loss tangent (Tan[delta]) at 10 GHz of 0.004 or less; and (iv) a layer thickness in the range of 10 [mu]m to 100 [mu]m. In addition, the polyimide (p) constituting the polyimide layer (P) contains an acid anhydride residue derived from tetracarboxylic acid dianhydride and a diamine residue derived from a diamine component, wherein the diamine residue at least 30 mol% of diamine residue derived from 1,3-bis(aminophenoxy)benzene with respect to the total diamine residue.

Description

Polyimide film, metal-clad laminate, method for producing metal-clad laminate, and circuit board

The present invention relates to a polyimide film for forming an electronic material such as a circuit board, a metal-clad laminate, and a circuit board formed by processing the same.

In the manufacture of circuit boards such as flexible circuit boards (Flexible Printed Circuit Boards (FPC)), metal-clad laminates in which metal layers such as copper foil are laminated on one or both sides of a polyimide insulating layer are widely used plate. Such polyimide insulating layers are generally required to exhibit relatively low relative permittivity and dielectric loss tangent for the purpose of improving high-frequency transmission characteristics of circuits.

However, the formation of the polyimide insulating layer of the metal-clad laminate is carried out by a "casting method" in which a polyimide solution is applied on the metal layer, dried, and then subjected to an imidization heat treatment. During the imidization heat treatment, between the metal layer and the polyimide insulating layer, a phenomenon called "swelling" or "peeling" may occur due to the volume expansion of the residual solvent or the generated imidization water. (Hereinafter, it may be referred to as a foaming phenomenon).

Therefore, as a metal-clad laminate in which the foaming phenomenon is suppressed without deteriorating the dielectric properties, a metal-clad laminate containing 40 parts by mole of acid anhydride residues constituting the polyimide insulating layer in total of 100 parts by mole has been proposed. Molar part or more of the tetracarboxylic dianhydride residue having a ketone group as a higher polar group in the molecule, so that the storage elastic modulus of the polyimide insulating layer in contact with the metal layer is a predetermined value or more ( Patent Document 1).

However, as described above, metal-clad laminates are also widely used, in which metal layers are provided on both sides of the polyimide insulating layer. However, metal-clad laminates are usually made of two metal-clad laminates on one side. The polyimide insulating layers of the laminate face each other, and the polyimide insulating layers are bonded to each other by a double-sided adhesive sheet (hereinafter, bonding sheet (BS)) in which a polyimide-based adhesive is formed into a sheet. The imine insulating layers are bonded to each other and produced. In the case where the metal-clad laminate of Patent Document 1 is used as a double-sided metal-clad laminate, it is produced by the same method. [Prior Art Literature] [Patent Literature]

Japanese Patent Laid-Open No. 2020-104340

[The problem to be solved by the invention]

However, in the case of the metal-clad laminate of Patent Document 1, attention is paid to ensuring the adhesiveness of the interface between the metal layer and the adjacent polyimide insulating layer, and the polyimide insulating layer on the opposite side of the metal layer is made of the polyimide insulating layer. Adhesion of the interface between the extremely flat surface of the layer and the bonding sheet has not been sufficiently studied. In addition, since the acid anhydride residue constituting the polyimide contains 40 mole parts or more of a tetracarboxylic dianhydride residue having a ketone group as a relatively polar group in the molecule, there is not only a relative permittivity but also a dielectric Loss tangent is also prone to rising problems. Therefore, according to Patent Document 1, it has not been found that the polyimide insulating layer of the metal-clad laminate can not only suppress the foaming phenomenon without deteriorating its dielectric properties, but also achieve good adhesion at the interface with the bonding sheet. The specific structure of sex.

An object of the present invention is to provide a polyimide film or a metal-clad laminate that can realize the bonding between the polyimide film or the polyimide insulating layer and the bonding sheet without deteriorating the dielectric properties. The specific structure of the good adhesion of the interface. [Means of Solving Problems]

The inventors of the present invention have studied a huge number of specific elements in the polyimide film or the polyimide insulating layer of the metal-clad laminate, and found that by controlling the extremely limited ones shown in the following (a) to (c) The specific elements can achieve the object of the present invention, thereby completing the present invention. (a) using a polyimide film or a polyimide insulating layer as a plurality of polyimide layers, and disposing a specific polyimide layer on the exposed surface side; (b) setting the "oxygen transmission coefficient", "thermal expansion coefficient", "dielectric loss tangent", and "layer thickness" of the polyimide film or the entire polyimide insulating layer within the specified ranges, respectively; and (c) The polyimide constituting the polyimide layer on the exposed surface side of the polyimide film or the polyimide insulating layer is made of 1,3-bis(aminophenoxy) in a predetermined content or more. A benzene-derived diamine residue is used as the diamine residue.

That is, the first aspect of the present invention provides a polyimide film having a plurality of polyimide layers, and the polyimide film is characterized by satisfying the following conditions (i) to (iv): [i] The oxygen permeability coefficient is below 2.0×10-18 mol·m/m2·s·Pa; [ii] The thermal expansion coefficient is in the range of 10 ppm/K to 30 ppm/K; [iii] a dielectric loss tangent (Tanδ) of 0.004 or less at 10 GHz; and [iv] The thickness is in the range of 10 μm to 100 μm; The polyimide film has a polyimide layer (P) on at least one exposed side, The polyimide (p) constituting the polyimide layer (P) contains an acid anhydride residue derived from a tetracarboxylic dianhydride component and a diamine residue derived from a diamine component. The group contains at least 30 mol % of diamine residues derived from a diamine compound represented by the following general formula (1) with respect to all the diamine residues.

[hua 1]

In addition, a second aspect of the present invention provides a metal-clad laminate, comprising a metal layer and a polyimide insulating layer having a plurality of polyimide layers, wherein the metal-clad laminate is characterized in that: (a) the The polyimide insulating layer has a polyimide layer (P) on the exposed surface side opposite to the metal layer, and (b) the polyimide insulating layer as a whole satisfies the following condition (i) ~Condition (iv): (i) The oxygen permeability coefficient is 2.0×10 ^-18 mol·m/m ² ·s·Pa or less; (ii) The thermal expansion coefficient is within the range of 10 ppm/K to 30 ppm/K; ( iii) the dielectric loss tangent (Tanδ) at 10 GHz is 0.004 or less; and (iv) the layer thickness is in the range of 10 μm to 100 μm; (c) the polyimide layer (P) constituting the polyimide layer The imide (p) contains an acid anhydride residue derived from a tetracarboxylic dianhydride component, and a diamine residue derived from a diamine component, and the diamine residue contains at least 30 moles relative to all the diamine residues % of a diamine residue derived from a diamine compound represented by the following general formula (1).

[hua 2]

In addition, a third aspect of the present invention provides a manufacturing method for manufacturing the metal-clad laminate, wherein the manufacturing method of the metal-clad laminate comprises: The step of coating the polyamide acid solution on the metal layer, and drying to form a single-layer or multi-layer first polyamide layer; A step of coating a solution of a polyamic acid that is a precursor of the polyimide (p) on the first polyamic acid layer, and drying to form a second polyamic acid layer; and The polyimide is formed by imidizing the polyamic acid contained in the first polyamic acid layer and the polyamic acid contained in the second polyamic acid layer step of insulating layer.

Further, a fourth aspect of the present invention provides a circuit board in which the metal layer of the metal-clad laminate is processed into wiring. [Effect of invention]

Regarding the polyimide film and the metal-clad laminate of the present invention, the polyimide film or the polyimide insulating layer is constituted by a plurality of polyimide layers, and the entire polyimide film or the polyimide insulating layer is constituted The overall "oxygen transmission coefficient", "thermal expansion coefficient", "dielectric loss tangent", and "layer thickness" are respectively set within predetermined ranges, so that the dimensional stability is excellent and the transmission loss can be reduced. In addition, in the polyimide film and the metal-clad laminate of the present invention, by arranging the specific polyimide layer on the exposed surface side, the polyimide film or the polyimide insulating layer as a whole can be avoided. In the case where the dielectric properties of , for example, are lowered, good adhesion can be achieved at the interface with resin materials such as bonding sheets, for example. Therefore, the metal-clad laminate of the present invention can be processed into a double-sided metal-clad laminate without impairing the good properties of the single-sided metal-clad laminate. In addition, the circuit board formed of the metal-clad laminate of the present invention is excellent in dimensional stability and heat resistance, and can obtain good high-frequency transmission characteristics.

Hereinafter, the polyimide film and the metal-clad laminate of the present invention will be described with reference to the accompanying drawings.

[The polyimide film of the present invention and the metal-clad laminate of the present invention] The polyimide film of the present invention has a plurality of polyimide layers. In addition, the metal-clad laminate of the present invention includes a metal layer and a polyimide insulating layer having a plurality of polyimide layers. Here, the polyimide film of the present invention is different from the metal-clad laminate of the present invention in that it does not necessarily contain a metal layer. That is, the polyimide film of the present invention has substantially the same structure as the "polyimide insulating layer" in the metal-clad laminate of the present invention. Hereinafter, in order to avoid redundant description, the structure of the polyimide film of the present invention is also clarified in the process of describing the metal-clad laminate of the present invention in detail. In the following description, the "polyimide insulating layer" in the metal-clad laminate may be replaced by the "polyimide film" unless otherwise noted.

FIG. 1 is a schematic cross-sectional view showing the basic structure of one embodiment of the metal-clad laminate 30 of the present invention. The metal-clad laminate 30 has a structure in which a polyimide insulating layer 20 is provided on one side of the metal layer 10 , and has structures (a), structures (b) (i) to (vi), and structures (c). Hereinafter, each structure will be described in detail. Further, as described above, the polyimide film of the present invention has the same structure as that of the polyimide insulating layer 20 of the metal-clad laminate 30 .

<Structure (a)> (Polyimide insulating layer 20) In the present invention, the polyimide insulating layer 20 includes a polyimide layer 21 including a single or multiple polyimide layers, and a polyimide layer containing a specific polyimide (p) described later. (P) 23, the polyimide layer (P) 23 is provided as a part thereof on the surface side of the polyimide insulating layer 20 on the opposite side to the metal layer 10 . In FIG. 1, the polyimide layer (P) 23 is exposed. Moreover, in the case of the polyimide film of this invention, what is necessary is just to provide a polyimide layer (P) on at least one exposed surface side.

The polyimide layer 21 includes a single or multiple polyimide layers. In order to ensure high heat resistance and high dimensional stability, the main polyimide layer is preferably a non-thermoplastic polyimide containing a non-thermoplastic polyimide. The imine layer may contain a thermoplastic polyimide layer containing thermoplastic polyimide within a range that does not impair the effects of the invention. Here, the total thickness of the main polyimide layers is preferably 50% or more relative to the thickness of the polyimide layer 21 . Moreover, in order to improve the adhesiveness of the polyimide surface of the polyimide insulating layer 20, the polyimide layer (P) 23 is laminated|stacked on the exposed surface side of the polyimide layer 21. The polyimide constituting the polyimide layer (P) 23 is not limited to thermoplastic polyimide or non-thermoplastic polyimide, and is a polyimide that can improve adhesion to other materials.

Both non-thermoplastic polyimide and thermoplastic polyimide are obtained by subjecting a tetracarboxylic dianhydride component and a diamine component to an imidization reaction, and the monomer residues include those derived from the tetracarboxylic dianhydride component. The tetravalent acid anhydride residue of , and the divalent diamine residue derived from the diamine component. These tetracarboxylic dianhydride components and diamine components will be described later in relation to thermoplastic polyimide and non-thermoplastic polyimide.

In the present invention, "non-thermoplastic" of "non-thermoplastic polyimide" means that the storage elastic modulus at 30°C measured using a dynamic viscoelasticity measuring device (dynamic mechanical analysis (DMA)) is 1.0 ×10 ⁹ Pa or more, and the storage elastic modulus in the temperature range within the glass transition temperature+30°C is 1.0 × 10 ⁸ Pa or more. In addition, the "thermoplastic" of "thermoplastic polyimide" means that the storage elastic modulus at 30°C measured by a dynamic viscoelasticity measuring device (DMA) is 1.0×10 ⁹ Pa or more, and the glass transition temperature is +30°C The storage elastic modulus in the temperature range within the range was less than 1.0×10 ⁸ Pa.

In addition, the non-thermoplastic polyimide layer constitutes a low thermal expansion polyimide layer, and the thermoplastic polyimide layer constitutes a high thermal expansion polyimide layer. Here, the "low thermal expansion" of the low thermal expansion polyimide layer means that the coefficient of thermal expansion (CTE) is preferably 1 ppm/K or more and 25 ppm/K or less, and more preferably 3 ppm/K. In the range of K or more and 25 ppm/K or less, on the other hand, the "high thermal expansion" of the high thermal expansion polyimide layer means that the CTE is preferably 35 ppm/K or more and 80 ppm/K or less, more preferably It is in the range of 35 ppm/K or more and 70 ppm/K or less. The thermal expansion of the polyimide layer can be adjusted by appropriately changing the monomer composition of the polyimide, the thickness of the polyimide insulating layer, and the conditions for forming the polyimide layer (coating, drying, curing), etc. .

<Structure (b)> In the metal-clad laminate 30 of the present embodiment, the polyimide insulating layer 20 as a whole satisfies the following conditions (i) to (iv).

(i) The oxygen permeability coefficient is 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa or less. In the present invention, the oxygen permeability coefficient of the polyimide insulating layer 20 is adjusted to be 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa or less. The measurement of the oxygen transmission coefficient can be performed according to the differential pressure method of Japanese Industrial Standards (JIS) K-7126-1. By adjusting the oxygen permeability coefficient to be 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa or less, it is possible to reduce the dielectric by suppressing the movement of the molecules of the polyimide constituting the polyimide insulating layer 20 . loss tangent. In addition, when circuit processing is performed on the metal layer 10 of the metal-clad laminate 30 and the polyimide insulating layer 20 is used as the insulating resin layer of the circuit board, even in the environment of repeated exposure to high temperature, it is possible to It maintains the adhesion with the wiring layer for a long time, and can obtain excellent long-term heat-resistant adhesion. When the oxygen permeability coefficient of the polyimide insulating layer 20 exceeds 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa, the oxygen permeating the polyimide insulating layer 20 promotes oxidation of the wiring layer, thereby promoting oxidation of the wiring layer. As a result, the adhesion between the wiring layer and the polyimide insulating layer 20 may decrease. In addition, the oxygen permeability coefficient of the polyimide insulating layer 20 can be adjusted not only by the thickness or the thickness ratio of the polyimide layer 21 , but also by the polyimide constituting the polyimide layer 21 . Among them, it is preferable to adjust the ratio of residues containing a biphenyl skeleton in the non-thermoplastic polyimide, the presence or absence of aliphatic skeleton residues, and the types of substituents of diamine residues and acid anhydride residues.

(ii) The coefficient of thermal expansion (CTE) is in the range of 10 ppm/K to 30 ppm/K. In the present invention, the coefficient of thermal expansion (CTE) of the entire polyimide insulating layer 20 is adjusted to 10 ppm/K or more and 30 ppm/K or less, preferably 10 ppm/K or more and 25 ppm/K or less, More preferably, it is adjusted to 15 ppm/K or more and 25 ppm/K or less. Thereby, in the metal-clad laminate 30 , the occurrence of warpage and the reduction of dimensional stability can be prevented. When the CTE of the entire polyimide insulating layer 20 exceeds the range of 10 ppm/K to 30 ppm/K, warpage or dimensional stability may be reduced. In addition, regarding the coefficient of thermal expansion (CTE) of the polyimide insulating layer 20 , the main polyimide layer is set as a non-thermoplastic polyimide layer, except that the In addition to adjusting the thickness ratio of the thermoplastic polyimide layer, the non-thermoplastic polyimide layer can also be adjusted by a residue containing a phenyl skeleton or a residue containing a naphthalene skeleton in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer. The ratio of rigid monomer residues such as residues of the biphenyl skeleton, heat treatment conditions in the imidization step, and the like can be adjusted.

(iii) The dielectric loss tangent (Tanδ) at 10 GHz is 0.004 or less. In the present invention, the dielectric loss tangent (Tanδ) at 10 GHz of the entire polyimide insulating layer 20 is adjusted to be 0.004 or less. Accordingly, when the polyimide insulating layer 20 of the metal-clad laminate 30 is used, for example, as an insulating resin layer of a circuit board, the dielectric loss at the time of transmitting a high-frequency signal can be reduced. Here, the dielectric loss tangent can be measured by a split post dielectric resonator (SPDR). Therefore, when the polyimide insulating layer 20 is used, for example, as an insulating resin layer of a high-frequency circuit board, transmission loss can be efficiently reduced. In addition, if the dielectric loss tangent at 10 GHz exceeds 0.004, when the polyimide insulating layer 20 is used as an insulating resin layer of a circuit board, there is a possibility that electrical signals may be generated on the transmission path of high-frequency signals. Defects such as increased loss. The lower limit value of the dielectric loss tangent at 10 GHz is not particularly limited, and can be determined according to required characteristics when the polyimide insulating layer 20 is used as an insulating resin layer of a circuit board. In addition, the dielectric loss tangent (Tanδ) of the polyimide insulating layer 20 can be adjusted not only by the thickness ratio of the polyimide layer 21 , but also by the thickness of the polyimide layer 21 . The ratio of the residues containing a biphenyl skeleton in the imide or the proportion of the imide group is adjusted.

On the other hand, when the polyimide insulating layer 20 is used as an insulating resin layer of a circuit board, for example, in order to ensure impedance matching, a split-column dielectric resonator (SPDR) is used as the entire polyimide insulating layer 20 . The relative permittivity measured at 10 GHz is preferably 4.0 or less. The reason for this is that if the relative dielectric constant at 10 GHz exceeds 4.0, when the polyimide insulating layer 20 is used as the insulating resin layer of the circuit board, the dielectric loss may increase, and it is easy to cause high dielectric loss. The loss of the power-on signal increases in the transmission path of the frequency signal, etc. In addition, the reason is that when the layer thickness of the polyimide insulating layer 20 is fixed, the higher the relative permittivity, the narrower the circuit wiring width at the time of impedance matching. Therefore, it is also likely to cause an increase in conductor loss. .

<(iv) The layer thickness is in the range of 10 μm to 100 μm. > In the present invention, the thickness of the entire polyimide insulating layer 20 is set within a range of 10 μm to 100 μm. The reason for this is that when the thickness is too thin, the polyimide insulating layer 20 is likely to be cracked. On the other hand, when the layer thickness is too thick, when the metal-clad laminate 30 is bent, the metal layer may be cracked. 10 has cracks. In addition, within the range of 10 μm to 100 μm, the layer thickness of the entire polyimide insulating layer 20 can be set to an appropriate layer thickness according to the purpose of use of the metal-clad laminate 30 . For example, when the metal-clad laminate 30 is applied to a circuit board, it can be preferably set within a range of 30 μm to 60 μm, more preferably 35 μm to 50 μm.

<Structure (c)> (Polyimide layer (P) 23) In the present invention, the polyimide layer (P) 23 is exposed on the surface of the metal-clad laminate 30 , for example, to form an exposed surface to which the bonding sheet is directly bonded. The polyimide (p) constituting the polyimide layer (P) 23 contains an acid anhydride residue derived from a tetracarboxylic dianhydride component and a diamine residue derived from a diamine component. Contains at least 30 mol %, preferably at least 50 mol % of all diamine residues, derived from a diamine compound (1,3-bis(aminophenoxy)benzene) represented by the following general formula (1) the diamine residue.

[hua 3]

The diamine compound represented by the general formula (1) has two aminophenoxy groups at the meta-position of the central benzene ring. Therefore, the rotational motion caused by the meta-bonding is suppressed, and the molecular weight is larger than that of a general diamine compound such as bis(aminophenyl) ether, so that the increase in the concentration of the imide group can be suppressed, and the polymer The imide insulating layer 20 achieves low dielectric constant and low dielectric loss tangent. Moreover, even if it reacts with the highly polar tetracarboxylic dianhydride which is easy to degrade a dielectric characteristic, it can ensure the adhesiveness with a bonding sheet without deteriorating a dielectric characteristic.

As the diamine compound represented by the general formula (1), 1,3-bis(3-aminophenoxy)benzene (1,3-bis(3-aminophenoxy)benzene, APB), 1,3-bis (4-aminophenoxy)benzene (1,3-bis(4-aminophenoxy)benzene, TPE-R) and the like. In particular, 1,3-bis(4-aminophenoxy)benzene (TPE-R) is preferable in that a favorable rotational motion inhibitory effect by meta-bonding can be expected.

The diamine residue of the polyimide (p) contains at least 30 mol %, preferably at least 50 mol %, and more preferably at least 70 mol % of the compound represented by the general formula (1) with respect to all the diamine residues. A diamine residue derived from a diamine compound. The reason for this is that if the content of the diamine residue derived from the diamine compound represented by the general formula (1) is too small, there is a possibility that the lowering of the dielectric constant and the lowering of the dielectric loss may not be achieved in the polyimide insulating layer 20 . Tangent.

In addition, the diamine residue of the polyimide (p) constituting the polyimide layer (P) 23 may contain a diamine residue derived from a known diamine compound within a range that does not impair the effects of the present invention base. Examples of such known diamine compounds include 1,4-diaminobenzene (p-PDA (para-phenylenediamine); p-phenylenediamine), 4-aminophenyl-4'-aminobenzoate (4-amino phenyl-4'-amino benzoate, APAB), 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide Ether, 3,3'-diaminodiphenyl ether, 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 , 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-aminophenoxy)phenoxy]aniline, 3-[3-(4-aminophenoxy)phenoxy yl]aniline, 4,4'-[2-methyl-(1,3-phenylene)dioxy]dianiline, 4,4'-[4-methyl-(1,3-phenylene) ) bisoxy] bisaniline, 4,4'-[5-methyl-(1,3-phenylene) bisoxy] bisaniline, bis[4,4'-(3-aminophenoxy) ] Benzoaniline, 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy) base)] bisaniline, bis[4-(4-aminophenoxy)phenyl]ether (bis[4-(4-aminophenoxy)phenyl]ether, BAPE), bis[4-(4-aminophenoxy) ) phenyl] sulfone (bis[4-(4-aminophenoxy)phenyl]sulfone, BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (bis[4-(4-aminophenoxy)phenyl] ketone, BAPK), 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (2, 2-bis[4-(4-aminophenoxy)phenyl]propane, BAPP), bis[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl] Methane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]benzophenone, 9,9-bis[4-(3-aminobenzene] oxy)phenyl]fluorene, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)benzene base] hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-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-phenylene bis(1-methyl) ethylene)] bisaniline, 4,4'-[1,3-phenylene bis(1-methylethylene)] bisaniline, bis(p-aminocyclohexyl)methane, bis(p-beta) -Amino-tert-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-tert-butyl)toluene, 2,4 -Diaminotoluene, m-xylylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene diamine, p-xylylene diamine, 2,6-diaminopyridine , 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, oxazine, 2'-methoxy-4,4'-diaminobenzidine, 4, 4'-Diaminobenzidine, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis[2-(4-aminophenyl)-2 -propyl]benzene, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, 6-amino-2-(4-aminophenoxy)benzoxazole, 2,6-Diamino-3,5-diethyltoluene, 2,4-diamino-3,5-diethyltoluene, 2,4-diamino-3,3'-diethyl-5, Aromatic diamine compounds such as 5'-dimethyldiphenylmethane, bis(4-amino-3-ethyl-5-methylphenyl)methane, and two terminal carboxylic acid groups of dimer acids are substituted with Aliphatic diamine compounds such as dimer acid-type diamines formed from primary aminomethyl groups or amino groups, etc.

In addition, as the acid anhydride residue derived from the tetracarboxylic dianhydride component of the polyimide (p), it is possible to adopt a good balance between the low dielectric properties of the polyimide insulating layer 20 and the high density of the bonding sheet. A variety of acid anhydride residues. Among them, the acid anhydride residues in total contain preferably at least 60 mol %, more preferably at least 90 mol % with respect to all acid anhydride residues as follows: 3,3',4,4'- Anhydride residues derived from benzophenone tetracarboxylic dianhydride (3,3',4,4'-benzophenone tetracarboxylic dianhydride, BTDA) and pyromellitic acid with a relatively low molecular weight and therefore a relatively high concentration of imino groups Anhydride residues derived from pyromellitic dianhydride (PMDA). It may contain only BTDA or only PMDA, but in the case of containing both, the preferable range is 50 mol% to 80 mol% of BTDA and 20 mol% to 50 mol% of PMDA with respect to all acid anhydride residues. %.

Further, the acid anhydride residue of the polyimide (p) may contain an acid anhydride residue derived from a known tetracarboxylic dianhydride within a range not impairing the effects of the present invention. As such a known acid dianhydride, 1,4-phenylene bis(trimellitic acid monoester) dianhydride (1,4-phenylene bis(trimellitic acid monoester) dianhydride, TAHQ), 2,3 ,6,7-naphthalene tetracarboxylic dianhydride (2,3,6,7-naphthalene tetracarboxylic dianhydride, NTCDA), 3,3',4,4'-diphenyltetracarboxylic dianhydride, 4,4 '-Oxydiphthalic anhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride or 2,3,3',4'-benzophenone tetracarboxylic dianhydride , 2,3',3,4'-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3'',4,4''-p-triple Benzenetetracarboxylic dianhydride, 2,3,3'',4''-p-terphenyltetracarboxylic dianhydride or 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2 ,2-bis(2,3-dicarboxyphenyl)-propane dianhydride or 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3-dicarboxyphenyl) Methane dianhydride or bis(3,4-dicarboxyphenyl) methane dianhydride, bis(2,3-dicarboxyphenyl) bis(2,3-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) bis(3,4-dicarboxyphenyl) ,1-bis(2,3-dicarboxyphenyl)ethanedianhydride or 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride, 1,2,7,8-phenanthrene-tetra Carboxylic dianhydride, 1,2,6,7-phenanthrene-tetracarboxylic dianhydride or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride Anhydride, 2,2-bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexanedianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Anhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetra Carboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride 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-perylene-tetracarboxylic dianhydride, 3,4,9,10-perylene-tetracarboxylic dianhydride, 4,5,10,11-perylene-tetracarboxylic dianhydride 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 Aromatic tetracarboxylic dianhydrides such as dianhydrides, ethylene glycol bis-trimellitic anhydrides, and the like.

In the polyimide (p), thermal expansion can be controlled by selecting the types of the acid anhydride residues and diamine residues, or the respective molar ratios when two or more acid anhydride residues or diamine residues are used. coefficient, tensile modulus of elasticity, glass transition temperature, etc. In addition, when polyimide (p) has a plurality of structural units of polyimide, it may exist in the form of a block or may exist randomly, but it is preferable to exist randomly. Further, the polyimide (p) preferably contains an aromatic tetracarboxylic anhydride residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine. By making both the acid anhydride residue and the diamine residue contained in the polyimide (p) aromatic groups, the deterioration of the polyimide in the polyimide insulating layer 20 under a high temperature environment can be suppressed.

The imide group concentration of the polyimide (p) is preferably 30% by weight or less. Here, the "imide group concentration" refers to a value obtained by dividing the molecular weight of the imide group (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 30% by weight, the elastic modulus at a temperature equal to or higher than the glass transition temperature is unlikely to decrease, and the low hygroscopicity also deteriorates due to an increase in polar groups.

The weight average molecular weight of the polyimide (p) is, for example, preferably in the range of 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 film decreases and tends to become brittle. On the other hand, when the weight-average molecular weight exceeds 400,000, the viscosity tends to increase excessively, and problems such as uneven film thickness and streaks tend to occur during the coating operation.

In addition, in the polyimide insulating layer 20 of the present invention, by further stacking a metal layer (not shown) on the polyimide layer (P) 23, the polyimide layer (P) 23 can be used as a The adhesive layer functions.

(Polyimide layer 21) In the present invention, it is preferable that the polyimide layer 21 constituting the polyimide insulating layer 20 of the metal-clad laminate 30 includes a single or multiple polyimide layers, and the main polyimide layer contains a non-thermoplastic layer. A polyimide layer, the non-thermoplastic polyimide layer satisfies the following conditions (1) to (3). Each condition is explained below.

(1) The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains 50 mol% or more of monomer residues having a biphenyl skeleton in all monomer residues derived from all monomer components; (2) The thickness is in the range of 7 μm to 70 μm; and (3) The ratio of the thickness of the non-thermoplastic polyimide layer to the layer thickness of the entire polyimide insulating layer 20 is 70% or more.

(Condition (1)) The polyimide insulating layer 20 contains a non-thermoplastic polyimide layer as the main layer of the polyimide layer 21 . The reason is that it is easy to control the oxygen transmission coefficient, CTE and dielectric properties of the polyimide insulating layer 20 . Here, the "main layer" refers to a layer that occupies more than 50% of the entire thickness of the polyimide layer 21, preferably 60% to 100% of the thickness. In addition, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer preferably contains 50 mol % or more, more preferably 50 mol % or more of all monomer residues derived from all monomer components constituting the non-thermoplastic polyimide. 70 mol% or more of monomer residues having a biphenyl skeleton (hereinafter, sometimes referred to as "residues containing a biphenyl skeleton"). Thereby, the content ratio of the residue containing a biphenyl skeleton in the whole polyimide constituting the polyimide insulating layer 20 can be increased, the oxygen transmission coefficient can be reduced, and the dielectric loss tangent can be reduced. On the other hand, in order to maintain the required physical properties of the polyimide insulating layer 20 of the metal-clad laminate 30 used as a circuit board material, the ratio of residues containing a biphenyl skeleton relative to all monomer residues is preferably set to 80 mol% or less. Here, the biphenyl skeleton is a skeleton in which two phenyl groups are single-bonded. Therefore, the biphenyl skeleton-containing residue includes, for example, a biphenyl diyl residue, a biphenyl tetrayl residue, and the like. The aromatic ring contained in these residues may have arbitrary substituents. Typical examples of biphenyldiyl include biphenyl-3,3'-diyl residue and biphenyl-4,4'-diyl residue. As a representative example of a biphenyl tetrayl residue, a biphenyl-3,4,3',4'-tetrayl residue is mentioned.

In addition, in the non-thermoplastic polyimide layer, the ratio of residues containing a biphenyl skeleton relative to each of all diamine residues and all acid anhydride residues is preferably 20 mol % or more, and more preferably 30 mol % or more. , more preferably 40 mol% or more. By including 20 mol% or more of biphenyl skeleton-containing residues with respect to all diamine residues and all acid anhydride residues, the residues containing biphenyl skeletons tend to be present in diamine residues or acid anhydride residues. Compared with either case, the formation of the ordered structure of the entire polymer is further promoted, and the effect of reducing the oxygen transmission coefficient and the dielectric loss tangent is increased.

In addition, the residue containing a biphenyl skeleton is a structure derived from a raw material monomer, and may be derived from a tetracarboxylic dianhydride or a diamine compound.

Representative examples of acid anhydride residues having a biphenyl skeleton include 3,3',4,4'-biphenyl tetracarboxylic dianhydride (3,3',4,4'-biphenyl tetracarboxylic dianhydride, BPDA). , 2,3',3,4'-biphenyltetracarboxylic dianhydride, 4,4'-bisphenol-bis(trimellitic anhydride) and other acid dianhydride-derived residues. Among these, acid anhydride residues (hereinafter, also referred to as "BPDA residues") derived from BPDA are easily formed into an ordered structure of polymers, and can cause dielectric loss tangent or hygroscopicity by inhibiting the movement of molecules The performance is reduced, so it is preferable. In addition, BPDA residues can impart self-supporting properties to the gel film of polyimide, which is a precursor of polyimide.

Further, the acid anhydride residue of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer may contain, in addition to the acid anhydride residue having a biphenyl skeleton, known Anhydride residues derived from tetracarboxylic dianhydride. As such a known acid dianhydride, for example, pyromellitic dianhydride (PMDA), 1,4-phenylene bis(trimellitic acid monoester) dianhydride (TAHQ), 2,3,6 ,7-Naphthalenetetracarboxylic dianhydride (NTCDA), 3,3',4,4'-diphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 2,2 ',3,3'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride or 3,3',4,4'-diphenylmethane Ketone tetracarboxylic dianhydride, 2,3',3,4'-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3'',4, 4''-p-terphenyltetracarboxylic dianhydride, 2,3,3'',4''-p-terphenyltetracarboxylic dianhydride or 2,2'',3,3''-p-terphenyltetra Carboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-propane dianhydride or 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3 -Dicarboxyphenyl)methane dianhydride or bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)stilbene dianhydride or bis(3,4-dicarboxyphenyl) ) bis(2,3-dicarboxyphenyl) ethane dianhydride or 1,1-bis(3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7 ,8-phenanthrene-tetracarboxylic dianhydride, 1,2,6,7-phenanthrene-tetracarboxylic dianhydride or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7 -Anthracene tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6 - Naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2 ,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride or 2,7-dichloronaphthalene-1,4,5,8-tetra Carboxylic dianhydride, 2,3,6,7-(or 1,4,5,8-)tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-)tetracarboxylic acid dianhydride, 2,3,8,9-perylene-tetracarboxylic dianhydride, 3,4,9,10-perylene-tetracarboxylic dianhydride, 4,5,10,11-perylene-tetracarboxylic dianhydride Or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride Anhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy Aromatic tetracarboxylic dianhydrides such as diphenylmethane dianhydride, ethylene glycol bis-trimellitic anhydride, and the like.

On the other hand, as a representative example of the diamine compound which has a biphenyl skeleton, the diamine compound which has only two aromatic rings can be mentioned, and 2,2'-dimethyl-4,4'-diaminodiamino Benzene (2,2'-dimethyl-4,4'-diamino biphenyl, m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl (2,2'-diethyl-4, 4'-diamino biphenyl, m-EB), 2,2'-diethoxy-4,4'-diamino biphenyl (2,2'-diethoxy-4,4'-diamino biphenyl, m-EOB) , 2,2'-dipropoxy-4,4'-diaminobiphenyl (2,2'-dipropoxy-4,4'-diamino biphenyl, m-POB), 2,2'-di-n-propyl -4,4'-Diaminobiphenyl (2,2'-di-n-propyl-4,4'-diamino biphenyl, m-NPB), 2,2'-divinyl-4,4'-diphenyl Aminobiphenyl (2,2'-divinyl-4,4'-diamino biphenyl, VAB), 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl) base) biphenyl (4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, TFMB), etc. Since the residues derived from these diamine compounds have a rigid structure, they have a function of imparting an ordered structure to the entire polymer. By including residues derived from these diamine compounds, a polyimide with a low oxygen permeability coefficient and low hygroscopicity can be obtained, the moisture in the molecular chain can be reduced, and thus the dielectric loss tangent can be reduced. Among them, m-TB is preferable.

Further, the diamine residue of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer may contain, in addition to the above-mentioned diamine compound having a biphenyl skeleton, within a range that does not impair the effects of the present invention. Contains a diamine residue derived from a known diamine compound. As such a known diamine compound, for example, 1,4-diaminobenzene (p-PDA; p-phenylenediamine), 4-aminophenyl-4'-aminobenzoate (APAB), 3 ,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 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, 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-Aminophenoxy)phenoxy]aniline, 3-[3-(4-aminophenoxy)phenoxy]aniline, 1,3-bis(4-aminophenoxy) ) benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB), 4,4'-[2-methyl-(1,3-phenylene)dioxy] Dianiline, 4,4'-[4-methyl-(1,3-phenylene)dioxy]dianiline, 4,4'-[5-methyl-(1,3-phenylene) Dioxy] bisaniline, bis[4,4'-(3-aminophenoxy)]benzidine, 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy base]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]dianiline, bis[4-(4-aminophenoxy)phenyl]ether (BAPE), bis[ 4-(4-Aminophenoxy)phenyl] stilbene (BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), 2,2-bis-[4-(3- Aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), bis[4-(3-aminophenoxy)phenyl]thiane , bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]diphenyl Methanone, 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'-methylenediphenyl -o-Toluidine, 4,4'-methylenebis-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenyl Ethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-diphenylene Phenylbis(1-methylethylene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylene)]bisaniline, bis(p-aminocyclohexyl) Methane, bis(p-β-amino-tert-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-tert-butyl)toluene, 2, 4-Diaminotoluene, m-xylylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene diamine, p-xylylene diamine, 2,6-diamino Pyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, oxazine, 2'-methoxy-4,4'-diaminobenzidine, 4 ,4'-Diaminobenzidine, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis[2-(4-aminophenyl)- 2-propyl]benzene, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, 6-amino-2-(4-aminophenoxy)benzoxazole , 2,6-diamino-3,5-diethyltoluene, 2,4-diamino-3,5-diethyltoluene, 2,4-diamino-3,3'-diethyl-5 , 5'-dimethyldiphenylmethane, bis (4-amino-3-ethyl-5-methylphenyl) methane and other aromatic diamine compounds, dimer acid two terminal carboxylic acid groups are substituted Aliphatic diamine compounds such as dimer acid-type diamines, which are primary aminomethyl groups or amino groups, etc.

(Condition (2)) In the present invention, the thickness of the non-thermoplastic polyimide layer is preferably within a range of 7 μm to 70 μm. The thickness of the non-thermoplastic polyimide layer can be appropriately set in the range of 7 μm to 70 μm according to the purpose of use, but is more preferably in the range of 25 μm to 49 μm, and even more preferably in the range of 30 μm to 49 μm. If the thickness of the non-thermoplastic polyimide layer is within the range, the effect of improving the dielectric properties of the polyimide insulating layer 20 can be expected, and the increase in the oxygen permeability coefficient can be suppressed even under repeated exposure to high temperatures The lowering of the adhesiveness between the wiring layer and the insulating resin layer can also be suppressed.

(Condition (3)) In the present invention, the ratio of the thickness of the non-thermoplastic polyimide layer to the thickness of the entire polyimide insulating layer 20 is preferably 70% or more. Therefore, the excessive increase in the oxygen permeability coefficient of the polyimide insulating layer 20 can be suppressed, and the CTE control can also be facilitated. In addition, the polyimide layer (P) 23 that can be used in consideration of the reduction of the dielectric loss tangent The degree of freedom of choice increases, so it becomes easy to control the rate of dimensional change or adapt to high-speed transmission, for example when used for circuit boards. In addition, the larger the ratio, the easier it is to achieve the control of the oxygen permeability coefficient and the dimensional change rate, and the reduction of the dielectric loss tangent.

In non-thermoplastic polyimide, oxygen permeation can be controlled by selecting the types of the acid anhydride residues and diamine residues, or the respective molar ratios when two or more acid anhydride residues or diamine residues are used. coefficient, dielectric properties, thermal expansion coefficient, storage elastic modulus, tensile elastic modulus, etc. In addition, in the case where the non-thermoplastic polyimide has a plurality of structural units of the polyimide, it may be present in the form of a block or may be present at random, but it is preferably present at random. Further, the non-thermoplastic polyimide preferably contains an aromatic tetracarboxylic anhydride residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine. By setting both the acid anhydride residue and the diamine residue contained in the non-thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide insulating layer 20 in a high temperature environment can be improved.

The imide group concentration of the non-thermoplastic polyimide is preferably 33% by weight or less. Here, the "imide group concentration" refers to a value obtained by dividing the molecular weight of the imide group (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33% by weight, the hygroscopicity increases due to the increase in polar groups. In addition, by selecting the combination of the acid dianhydride and the diamine compound, the orientation of the molecules in the non-thermoplastic polyimide can be controlled, thereby suppressing the increase in CTE accompanying the decrease in the concentration of the imide group, thereby ensuring that the Low hygroscopicity.

The weight average molecular weight of the non-thermoplastic polyimide is, for example, preferably in the range of 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 film decreases and tends to become brittle. On the other hand, when the weight-average molecular weight exceeds 400,000, the viscosity tends to increase excessively, and problems such as uneven film thickness and streaks tend to occur during the coating operation.

The polyimide insulating layer 20 of the present embodiment may contain an inorganic filler or an organic filler in the polyimide layer 21 or the polyimide layer (P) 23 as needed. Specifically, for example, inorganic fillers such as silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, and calcium fluoride, or fluorine-based polymer particles or Organic fillers such as liquid crystal polymer particles. These can be used alone or in combination of two or more.

In addition, in the present invention, the polyimide layer 21 of the polyimide insulating layer 20 may be directly laminated on the metal layer 10 as a single-layer non-thermoplastic polyimide layer.

<Metal layer> The material of the metal layer 10 is not particularly limited, and examples thereof include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese and alloys of these, etc. Among them, copper or a copper alloy is particularly preferable. In addition, the material of the wiring layer in the circuit board described later is also the same as that of the metal layer 10 .

The thickness of the metal layer 10 is not particularly limited. For example, when a metal foil represented by copper foil is used, the upper limit of the thickness is preferably 35 μm or less, and more preferably in the range of 5 μm to 25 μm. From the viewpoint of production stability and handleability, the lower limit of the thickness of the metal foil is preferably 5 μm. Moreover, as a copper foil used as the metal layer 10, a rolled copper foil may be sufficient, and an electrolytic copper foil may be sufficient as it. Moreover, as copper foil, a commercially available copper foil can be used.

In addition, the ten-point average roughness (Rzjis) of the surface of the metal layer 10 in contact with the polyimide layer 21 is preferably 1.2 μm or less, and more preferably 1.0 μm or less. When the metal layer 10 is made of metal foil, by setting the surface roughness Rzjis to 1.2 μm or less, fine wiring processing corresponding to high-density mounting can be performed, and conductor loss during high-frequency signal transmission can be reduced. Therefore, it can be applied to a circuit board for high-frequency signal transmission. When the surface roughness Rzjis exceeds 1.2 μm, the wiring shape at the time of fine wiring processing deteriorates and processing becomes difficult, and the conductor loss increases, which is not suitable for high-frequency signal transmission.

In addition, the metal layer 10 may be subjected to, for example, rust-preventive treatment in advance, or surface treatment with, for example, siding, aluminum alkoxide, aluminum chelate, silane coupling agent, etc. for the purpose of improving the adhesive force. .

[Manufacturing method of metal-clad laminate] The metal-clad laminate 30 of the present invention can be manufactured by a manufacturing method having the following steps (A), (B), and (C).

<Step (A)> On the metal foil to be the metal layer 10 , a solution of polyamic acid, which is a precursor of polyimide, is applied and dried to form a single-layer or multi-layer first polyamic acid layer. There are no particular limitations on the method of applying the polyamide solution to the metal layer 10, and for example, it can be applied using a coater such as a cutout wheel, a die, a knife, or a die lip. Moreover, when the 1st polyamic acid layer is made into multiple layers, for example, the method of repeatedly applying a polyamic acid solution to the metal foil and drying it, or by extruding multiple layers can be used. A method of coating and drying the metal foil in a state where polyamic acid is laminated in multiple layers at the same time.

The solution of polyamic acid is obtained by dissolving the acid dianhydride component and the diamine component in approximately equimolar amounts in organic compounds such as N,N-dimethylformamide (N,N-dimethylformamide, DMF). In the solvent, the polymerization reaction is carried out by stirring at a temperature in the range of 0°C to 100°C for 30 minutes to 24 hours. Usually, it is preferable to adjust the polyamic acid concentration of the polyamic acid solution to a usage amount of about 5 to 30 wt %, and to set the viscosity to 500 cps to 100,000 cps.

<Step (B)> Next, on the first polyamic acid layer, by the same operation as in step (A), a solution of polyamic acid, which is a precursor of polyimide (p), is applied and dried to form a second polyamic acid solution. Dimer layer. In addition, the first polyamic acid layer and the second polyamic acid layer may be simultaneously formed by multi-layer extrusion in the same manner as described above.

<Step (C)> Next, the polyamic acid contained in the first polyamic acid layer and the polyamic acid contained in the second polyamic acid layer are imidized to change into polyamic acid The amine layer 21 and the polyimide layer (P) 23 form the polyimide insulating layer 20 . The method of imidizing the polyamide is not particularly limited, and for example, a heat treatment such as heating under temperature conditions in the range of 80° C. to 400° C. for 1 hour to 24 hours can be preferably employed. Thus, the metal-clad laminate 30 of FIG. 1 is obtained.

In addition, regarding the polyimide film of the present invention, in the method of manufacturing the metal-clad laminate 30, the metal layer 10 is removed by etching or the like after the metal-clad laminate 30 is manufactured, or a peelable substrate is used. (Including a peelable metal foil) In place of the metal foil, the metal-clad laminate 30 is manufactured and the metal layer 10 and the polyimide insulating layer 20 are peeled off to manufacture.

[circuit board] The metal-clad laminate 30 of the present invention is effectively used as a circuit board material such as FPC, and a circuit board produced by processing the metal-clad laminate 30 of the present invention is also an aspect of the present invention. The circuit substrate is formed by processing the metal layer 10 of the metal clad laminate 30 of the present invention into wiring by conventional methods, and its structural features inherit the structural features of the metal clad laminate 30 of the present invention. Therefore, this circuit board can obtain stable and good high-frequency transmission characteristics. [Example]

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

[Measurement of viscosity] The viscosities at 25°C of the polyamide acid solutions of Synthesis Examples 1 to 16 and A to C were measured using an E-type viscometer (manufactured by Brookfield, trade name: DV-II+Pro). Determination. The rotational speed was set so that the torque was 10% to 90%, and the value when the viscosity was stable was read after 2 minutes had elapsed from the start of the measurement.

[Measurement of Glass Transition Temperature and Storage Elastic Modulus] A polyimide film was cut into a size of 5 mm×70 mm, and a dynamic viscoelasticity measuring device (DMA: manufactured by TA Instruments, trade name: TA Instruments) was used. RSA G2), the glass transition temperature and the storage elastic modulus were measured from 30°C to 400°C at a heating rate of 4°C/min and a frequency of 10 Hz. The temperature at which the elastic modulus change (tan δ) becomes the maximum is defined as the glass transition temperature. From these measurement results, the "non-thermoplasticity" of the polyimide film was judged. The case where the storage elastic modulus at 30°C is 1.0×10 ⁹ Pa or more, and the storage elastic modulus at the temperature range within the glass transition temperature+30°C is 1.0×10 ⁸ Pa or more is defined as “non-thermoplastic” .

[Measurement of Coefficient of Thermal Expansion (CTE)] The polyimide films obtained by removing the copper foil of the single-sided copper-clad laminates of Examples 1 to 30 and Comparative Examples 1 to 4 were cut into a size of 3 mm×20 mm, and a thermomechanical analyzer was used. (manufactured by Hitachi High-Tech Science (formerly Seiko Instruments), trade name: TMA/SS6100), while applying a load of 5.0 g, the temperature was increased from 30°C to 260°C, and then kept at this temperature for 10 minutes, then cooled at a rate of 5°C/min, and obtained as an average thermal expansion coefficient (thermal expansion coefficient) from 250°C to 100°C. In practical applications, the thermal expansion coefficient is expected to be in the range of 10 ppm/K to 30 ppm/K.

[Measurement of peel strength] Two polyimide films obtained by removing the copper foil of the single-sided copper-clad laminates of Examples 1 to 30 and Comparative Examples 1 to 4 and a bonding sheet (polyimide series, Nippon Steel Chemicals) & material (manufactured by Nippon Steel Chemical & Material, trade name: NB25A-M, thickness: 25 μm) so that the opposite surface of the polyimide film contacting the copper foil may be in contact with the bonding sheet, and used The vacuum press was heated and crimped for 60 minutes at a temperature of 160° C. and a surface pressure of 3.5 MPa. The obtained laminate was cut into a width of 5 mm, and the obtained laminate was cut into a width of 50 mm in the 180° direction using a Tensilon Tester (trade name: Strograph VE-1D, manufactured by Toyo Seiki Co., Ltd.). One of the polyimide films was stretched at a speed of /min, and the peel strength was obtained from the median strength when peeled at 20 mm. The peel strength is expected to be 0.7 kN/m or more in practical use.

[Determination of relative permittivity and dielectric loss tangent] For the polyimide films obtained by removing the copper foil of the single-sided copper-clad laminates of Examples 1 to 30 and Comparative Examples 1 to 4, a vector network analyzer (manufactured by Agilent) was used. Trade name: E8363C) and a split column dielectric resonator (SPDR resonator) to measure the relative permittivity and dielectric loss tangent of a polyimide film at a frequency of 10 GHz. In addition, the material used for the measurement was left to stand for 24 hours under the conditions of temperature: 24° C. to 26° C. and humidity: 45% to 55%. In practical applications, the relative permittivity is desirably 3.5 or less, and the dielectric loss tangent is 0.004 or less.

[Measurement of Oxygen Permeability Coefficient] For the polyimide films obtained by removing the copper foil of the single-sided copper-clad laminates of Examples 1 to 30 and Comparative Examples 1 to 4, the temperature was 23° C.±2° C. , Under the condition of 65% relative humidity (RH) ±5% RH, the oxygen transmission coefficient is measured according to the differential pressure method of JIS K7126-1. In addition, as a vapor transmission rate measuring apparatus, GTR-30XAD2 manufactured by GTR Technology (TEC) and G2700T·F manufactured by Yanaco Technical Science were used. In practical use, the oxygen permeability coefficient is desirably 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa or less.

The abbreviations used in the following synthesis examples, examples, and comparative examples represent the following compounds. PMDA: pyromellitic dianhydride BTDA: 3,3',4,4'-benzophenone tetracarboxylic dianhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-bis(4-aminophenoxy)benzene TPE-Q: 1,4-bis(4-aminophenoxy)benzene APB: 1,3-bis(3-aminophenoxy)benzene BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane BAPB: 4,4'-bis(4-aminophenoxy)biphenyl 4,4'-DAPE: 4,4'-diaminodiphenyl ether Dianiline-P: 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (manufactured by Mitsui Fine Chemicals Co., Ltd., trade name: Dianiline-P) DMAc: N,N-dimethylacetamide)

(Synthesis Example 1) In a 500 ml separable flask, 20.670 g of TPE-R (0.0707 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 15.330 g of PMDA (0.0703 mol), stirring was continued at room temperature for 3 hours, and a polymerization reaction was performed to obtain a polyamic acid solution 1 of the composition of Table 1. The solution viscosity of Polyamide Solution 1 was 4,600 cps.

(Synthesis example 2) In a 500 ml separable flask, 19.862 g of TPE-R (0.0680 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were put into a 500 ml separable flask under a nitrogen gas stream, and they were dissolved by stirring at room temperature. . Next, after adding 11.785 g of PMDA (0.0540 mol) and 4.353 g of BTDA (0.0135 mol), stirring was continued at room temperature for 3 hours to perform a polymerization reaction, thereby obtaining a polyamic acid solution 2. The solution viscosity of the polyamic acid solution 2 of the composition of Table 1 was 4,300 cps.

(Synthesis Example 3) In a 500 ml separable flask, 19.482 g of TPE-R (0.0666 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 10.114 g of PMDA (0.0464 mol) and 6.404 g of BTDA (0.0199 mol), stirring was continued at room temperature for 3 hours, and a polymerization reaction was performed to obtain a polyamic acid solution 3. The solution viscosity of the polyamic acid solution 3 of the composition of Table 1 was 4,000 cps.

(Synthesis Example 4) In a 500 ml separable flask, 19.116 g of TPE-R (0.0654 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 8.506 g of PMDA (0.0390 mol) and 8.378 g of BTDA (0.0260 mol), stirring was continued at room temperature for 3 hours, and a polymerization reaction was performed to obtain a polyamic acid solution 4. The solution viscosity of the polyamic acid solution 4 of the composition of Table 1 was 4,300 cps.

(Synthesis Example 5) In a 500 ml separable flask, 18.763 g of TPE-R (0.0642 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were put in a nitrogen gas stream, and they were dissolved by stirring at room temperature. . Next, after adding 6.958 g of PMDA (0.0319 mol) and 10.279 g of BTDA (0.0319 mol), stirring was continued at room temperature for 3 hours to carry out the polymerization reaction, thereby obtaining a polyamic acid solution 5. The solution viscosity of the polyamic acid solution 5 of the composition of Table 1 was 4,400 cps.

(Synthesis Example 6) In a 500 ml separable flask, 18.095 g of TPE-R (0.0619 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 4.026 g of PMDA (0.0185 mol) and 13.879 g of BTDA (0.0431 mol), stirring was continued at room temperature for 3 hours to perform a polymerization reaction, whereby a polyamic acid solution 6 was obtained. The solution viscosity of the polyamic acid solution 6 of the composition of Table 1 was 3,700 cps.

(Synthesis Example 7) In a 500 ml separable flask, 17.779 g of TPE-R (0.0608 mol) and DMAc so that the solid content concentration after polymerization was 12 wt% were put into a 500 ml separable flask under nitrogen gas flow, and were dissolved by stirring at room temperature. . Next, after adding 2.637 g of PMDA (0.0121 mol) and 15.584 g of BTDA (0.0484 mol), stirring was continued at room temperature for 3 hours, and a polymerization reaction was performed to obtain a polyamic acid solution 7. The solution viscosity of the polyamic acid solution 7 of the composition of Table 1 was 3,400 cps.

(Synthesis Example 8) In a 500 ml separable flask, 17.178 g of TPE-R (0.0588 mol) and DMAc so that the solid content concentration after polymerization was 12 wt % were put into a 500 ml separable flask under nitrogen flow, and the mixture was stirred and dissolved at room temperature. . Next, after adding 18.822 g of BTDA (0.0584 mol), stirring was continued at room temperature for 3 hours, and a polymerization reaction was performed to obtain a polyamic acid solution 8 of the composition of Table 1. The solution viscosity of Polyamide Solution 8 was 3,800 cps.

(Synthesis Example 9) In a 500 ml separable flask, 18.182 g of TPE-R (0.0622 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 4.046 g of PMDA (0.0185 mol), 11.953 g of BTDA (0.0371 mol), and 1.819 g of BPDA (0.0062 mol), stirring was continued at room temperature for 3 hours and polymerization reaction was performed, thereby obtaining Table 1 The composition of the polyamide solution 9. The solution viscosity of Polyamide Solution 9 was 4,100 cps.

(Synthesis Example 10) In a 500 ml separable flask, 18.270 g of TPE-R (0.0625 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were put in a nitrogen gas stream, and they were dissolved by stirring at room temperature. . Next, after adding 4.065 g of PMDA (0.0186 mol), 10.009 g of BTDA (0.0311 mol), and 3.656 g of BPDA (0.0124 mol), stirring was continued at room temperature for 3 hours and polymerization reaction was performed, thereby obtaining Table 1 The composition of the polyamide solution 10. The solution viscosity of Polyamide Solution 10 was 3,800 cps.

(Synthesis Example 11) In a 500 ml separable flask, 18.359 g of TPE-R (0.0628 mol) and DMAc with a solid content concentration after polymerization of 12 wt % were charged under nitrogen flow, and the mixture was stirred at room temperature to dissolve it. . Next, after adding 4.085 g of PMDA (0.0187 mol), 8.046 g of BTDA (0.0250 mol), and 5.510 g of BPDA (0.0187 mol), stirring was continued at room temperature for 3 hours and polymerization reaction was performed, thereby obtaining Table 1 The composition of the polyamide solution 11. The solution viscosity of the polyamide solution 11 was 4,300 cps.

(Synthesis Example 12) In a 500 ml separable flask, 14.476 g of TPE-R (0.0495 mol), 3.619 g of APB (0.0124 mol), and DMAc in such an amount that the solid content concentration after polymerization was 12 wt % were charged under nitrogen gas flow. It was dissolved by stirring at room temperature. Next, after adding 4.026 g of PMDA (0.0185 mol) and 13.879 g of BTDA (0.0431 mol), stirring was continued at room temperature for 3 hours, and the polymerization reaction was carried out to obtain a polyamic acid solution 12 having the composition of Table 1. . The solution viscosity of the polyamide solution 12 was 3,100 cps.

(Synthesis Example 13) In a 500 ml separable flask, 8.348 g of TPE-R (0.0286 mol), 11.723 g of BAPP (0.0286 mol), and DMAc in such an amount that the solid content concentration after polymerization was 12 wt % were charged under nitrogen flow. It was dissolved by stirring at room temperature. Next, after adding 4.953 g of PMDA (0.0227 mol) and 10.976 g of BTDA (0.0341 mol), the polymerization reaction was continued at room temperature for 3 hours while stirring to obtain a polyamic acid solution 13 having the composition of Table 1. . The solution viscosity of the polyamide solution 13 was 4,200 cps.

(Synthesis Example 14) In a 500 ml separable flask, 6.940 g of TPE-R (0.0237 mol), 13.120 g of BAPB (0.0356 mol), and DMAc in such an amount that the solid content concentration after polymerization was 12 wt % were charged under nitrogen flow. It was dissolved by stirring at room temperature. Next, after adding 6.434 g of PMDA (0.0295 mol) and 9.505 g of BTDA (0.0295 mol), stirring was continued at room temperature for 3 hours, and the polymerization reaction was performed to obtain a polyamic acid solution 14 having the composition of Table 1. . The solution viscosity of the polyamide solution 14 was 3,700 cps.

(Synthesis Example 15) In a 500 ml separable flask, 15.417 g of TPE-R (0.0527 mol), 2.799 g of m-TB (0.0132 mol), and 12 wt% of solid content after polymerization were charged under nitrogen flow. DMAc was dissolved by stirring at room temperature. Next, after adding 4.288 g of PMDA (0.0197 mol) and 13.496 g of BPDA (0.0459 mol), stirring was continued at room temperature for 3 hours, and the polymerization reaction was performed to obtain a polyamic acid solution 15 having the composition of Table 1. . The solution viscosity of Polyamide Solution 15 was 3,500 cps.

(Synthesis Example 16) In a 500 ml separable flask, 13.848 g of 4,4'-DAPE (0.0692 mol) and DMAc in such an amount that the solid content concentration after polymerization was 12 wt % were put into a 500 ml separable flask, and the mixture was stirred at room temperature. to dissolve. Next, after adding 22.152 g of BTDA (0.0687 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction, thereby obtaining a polyamic acid solution 16 of the composition of Table 1. The solution viscosity of Polyamide Solution 16 was 3,300 cps.

(Synthesis Example A) Under nitrogen flow, 120.612 g of m-TB (0.5681 mol), 9.227 g of TPE-Q (0.0316 mol), and 10.873 g of bisaniline-P (0.0316 mol) were put into a 3000 ml separable flask, and polymerized The resulting solid content concentration was DMAc in an amount of 15 wt %, which was dissolved by stirring at room temperature. Next, after adding 67.814 g of PMDA (0.3109 mol) and 91.474 g of BPDA (0.3109 mol), the polymerization reaction was continued at room temperature for 3 hours while stirring to obtain a polyamic acid solution A of the composition of Table 1. . The solution viscosity of Polyamide Solution A was 28,300 cps.

The polyamic acid solution A was uniformly applied on the base material so that the thickness after curing was about 25 μm, and then the solvent was removed by heating and drying at 120°C. Furthermore, the polyimide film obtained by performing stepwise heat treatment from 120° C. to 360° C. within 10 minutes to complete the imidization is non-thermoplastic.

(Synthesis Example B) In a 3000 ml separable flask, 127.501 g of m-TB (0.6006 mol), 12.976 g of BAPP (0.0316 mol), and DMAc in such an amount that the solid content concentration after polymerization was 15 wt% were charged under nitrogen gas flow. It was dissolved by stirring at room temperature. Next, after adding 67.914 g of PMDA (0.3114 mol) and 91.609 g of BPDA (0.3114 mol), stirring was continued at room temperature for 3 hours to carry out the polymerization reaction, thereby obtaining a polyamic acid solution B of the composition of Table 1. . The solution viscosity of Polyamide Solution B was 25,600 cps.

After the polyamic acid solution B was uniformly applied on the base material so that the thickness after curing was about 25 μm, the solution was heated and dried at 120° C. to remove the solvent. Furthermore, the polyimide film obtained by performing stepwise heat treatment from 120° C. to 360° C. within 10 minutes to complete the imidization is non-thermoplastic.

(Synthesis example C) In a 3000 ml separable flask, 114.972 g of m-TB (0.5416 mol), 39.580 g of TPE-R (0.1354 mol), and an amount of 15 wt % of solid content after polymerization were charged under nitrogen flow. DMAc was dissolved by stirring at room temperature. Next, after adding 145.447 g of PMDA (0.6668 mol), stirring was continued at room temperature for 3 hours to carry out a polymerization reaction, whereby a polyamic acid solution C of the composition of Table 1 was obtained. The solution viscosity of Polyamide Solution C was 27,200 cps.

The polyamic acid solution C was uniformly applied on the base material so that the thickness after curing was about 25 μm, and then the solvent was removed by heating and drying at 120°C. Furthermore, the polyimide film obtained by performing stepwise heat treatment from 120° C. to 360° C. within 10 minutes to complete the imidization is non-thermoplastic.

[Table 1] Polyamide solution Acid dianhydride [mol%] Diamine [mol%] PMDA BTDA BPDA TPE-R APB BAPP BAPB m-TB 4,4'-DAPE TPE-Q Dianiline-P 1 100 0 0 100 0 0 0 0 0 0 0 2 80 20 0 100 0 0 0 0 0 0 0 3 70 30 0 100 0 0 0 0 0 0 0 4 60 40 0 100 0 0 0 0 0 0 0 5 50 50 0 100 0 0 0 0 0 0 0 6 30 70 0 100 0 0 0 0 0 0 0 7 20 80 0 100 0 0 0 0 0 0 0 8 0 100 0 100 0 0 0 0 0 0 0 9 30 60 10 100 0 0 0 0 0 0 0 10 30 50 20 100 0 0 0 0 0 0 0 11 30 40 30 100 0 0 0 0 0 0 0 12 30 70 0 80 20 0 0 0 0 0 0 13 40 60 0 50 0 50 0 0 0 0 0 14 50 50 0 40 0 0 60 0 0 0 0 15 30 0 70 80 0 0 0 20 0 0 0 16 0 100 0 0 0 0 0 0 100 0 0 A 50 0 50 0 0 0 0 90 0 5 5 B 50 0 50 0 0 5 0 95 0 0 0 C 100 0 0 20 0 0 0 80 0 0 0

[Example 1] The polyamide solution A, which is the first layer in contact with the copper foil, was uniformly applied on the copper foil so that the thickness after curing was 23 μm, and then the solvent was removed by heating and drying at 120° C. for 2 minutes. The polyamic acid solution 1 as the second layer was uniformly coated on the first layer so that the thickness after curing was 2 μm, and then the solvent was removed by heating and drying at 130° C. for 30 seconds. Next, the imidization was completed by stepwise heat treatment at 140°C to 360°C, and a copper-clad laminate was produced. Then, the copper foil was removed by etching using an aqueous ferric chloride solution to obtain a polyimide film. The physical properties of the obtained polyimide film are shown in Table 2.

[Example 2] to [Example 15] and [Comparative Example 1] to [Comparative Example 2] As shown in Table 2, a polyimide film was obtained in the same manner as in Example 1, except that the polyimide solutions of the first layer and the second layer were changed.

[Table 2] Polyimide layer structure peel strength Dielectric properties oxygen transmission coefficient Thermal expansion coefficient level one Second floor [kN/m] Relative permittivity dielectric loss tangent [mol m/m ² s Pa] [ppm/K] Example 1 A 1 0.86 3.39 0.0037 1.32E-18 23.0 Example 2 A 2 0.85 3.39 0.0039 1.57E-18 23.2 Example 3 A 3 0.76 3.38 0.0038 1.25E-18 23.4 Example 4 A 4 0.99 3.39 0.0037 1.28E-18 23.6 Example 5 A 5 0.87 3.38 0.0037 1.42E-18 23.5 Example 6 A 6 0.95 3.36 0.0037 1.42E-18 23.8 Example 7 A 7 1.34 3.37 0.0037 1.53E-18 23.6 Example 8 A 8 1.36 3.36 0.0036 1.48E-18 23.9 Example 9 A 9 1.01 3.37 0.0038 1.57E-18 24.0 Example 10 A 10 0.87 3.36 0.0038 1.52E-18 23.7 Example 11 A 11 0.85 3.36 0.0037 1.39E-18 23.9 Example 12 A 12 1.14 3.36 0.0038 1.27E-18 24.0 Example 13 A 13 0.98 3.38 0.0038 1.28E-18 23.8 Example 14 A 14 0.83 3.37 0.0039 1.33E-18 23.8 Example 15 B 6 1.04 3.37 0.0038 1.18E-18 22.1 Comparative Example 1 A 16 1.41 3.4 0.0044 1.60E-18 23.7 Comparative Example 2 C 6 1.06 3.51 0.0071 2.48E-18 23.9

[Example 16] The polyamide solution A, which is the first layer in contact with the copper foil, was uniformly coated on the copper foil so that the thickness after curing was 47 μm, and then the solvent was removed by heating and drying at 120° C. for 4 minutes. The polyamic acid solution 1 as the second layer was uniformly applied on the first layer so that the thickness after curing was 3 μm, and then the solvent was removed by heating and drying at 130° C. for 1 minute. Next, the imidization was completed by stepwise heat treatment at 140°C to 360°C, and a copper-clad laminate was produced. Then, the copper foil was removed by etching using an aqueous ferric chloride solution to obtain a polyimide film. The physical properties of the obtained polyimide film are shown in Table 3.

[Example 17] to [Example 30] and [Comparative Example 3] to [Comparative Example 4] As shown in Table 3, a polyimide film was obtained in the same manner as in Example 16 except that the polyimide solutions of the first layer and the second layer were changed.

[table 3] Polyimide layer structure peel strength Dielectric properties oxygen transmission coefficient Thermal expansion coefficient level one Second floor [kN/m] Relative permittivity dielectric loss tangent [mol m/m ² s Pa] [ppm/K] Example 16 A 1 1.06 3.39 0.0037 1.20E-18 24.6 Example 17 A 2 1.08 3.39 0.0036 1.19E-18 24.6 Example 18 A 3 1.32 3.38 0.0038 1.34E-18 25.0 Example 19 A 4 1.18 3.38 0.0037 1.31E-18 24.9 Example 20 A 5 1.5 3.4 0.0036 1.30E-18 25.1 Example 21 A 6 1.57 3.37 0.0038 1.46E-18 24.9 Example 22 A 7 1.77 3.38 0.0036 1.51E-18 25.1 Example 23 A 8 1.9 3.37 0.0038 1.35E-18 25.5 Example 24 A 9 1.38 3.38 0.0036 1.19E-18 25.2 Example 25 A 10 1.2 3.36 0.0038 1.30E-18 25.3 Example 26 A 11 1.15 3.37 0.0038 1.35E-18 25.4 Example 27 A 12 1.61 3.37 0.0036 1.52E-18 25.5 Example 28 A 13 1.42 3.37 0.0037 1.59E-18 25.0 Example 29 A 14 1.29 3.36 0.0038 1.47E-18 25.3 Example 30 B 6 1.52 3.38 0.0036 1.16E-18 22.8 Comparative Example 3 A 16 1.93 3.38 0.0042 1.32E-18 24.8 Comparative Example 4 C 6 1.55 3.51 0.007 2.44E-18 25.0

In the polyimide films produced from the copper-clad laminates of Examples 1 to 30, 30 mol % or more of the diamine residues in the polyimide layer of the second layer is 1,3-bis(aminobenzene) oxy) benzene residue, and the (i) oxygen permeability coefficient of the polyimide insulating layer formed by laminating the first layer and the second layer is 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa or less , (ii) the thermal expansion coefficient is in the range of 10 ppm/K to 30 ppm/K, (iii) the dielectric loss tangent (Tanδ) at 10 GHz is below 0.004, and the layer thickness is in the range of 10 μm to 100 μm Therefore, the peel strength becomes 0.7 kN/m or more without deteriorating the dielectric properties. Therefore, it can be processed into a double-sided copper-clad laminate without impairing the good properties of the single-sided copper-clad laminate. In addition, the circuit board formed of the copper-clad laminate of the present invention can obtain stable and good high-frequency transmission characteristics.

On the other hand, from the results of Comparative Example 1 and Comparative Example 3, even if the first layer has low dielectric properties, if the second layer does not contain 1,3-bis(aminophenoxy)benzene residues, the damage the original low dielectric properties.

In addition, in the polyimide films made of the copper-clad laminates of Comparative Examples 2 and 4, the diamine residues of the second polyimide layer contained only 1,3-bis(aminophenoxy) ) benzene residues, so the peel strength is satisfactory, but due to the influence of the first layer, the oxygen permeability coefficient exceeds 2.0×10 ⁻¹⁸ mol·m/m ² ·s·Pa, and the dielectric loss tangent exceeds 0.004. Furthermore, in the case of Comparative Example 4, the thickness was twice that of the polyimide film in Comparative Example 2, but no improvement in dielectric loss tangent was observed.

From the above results, it was found that by adopting the structure of the example, a copper-clad laminate excellent in adhesion to the bonding sheet while maintaining low dielectric properties was obtained.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, it cannot be overemphasized that this invention is not limited by the said embodiment, Various deformation|transformation is possible.

10: Metal layer 20: Polyimide insulating layer 21: Polyimide layer 23: Polyimide layer (P) 30: Metal clad laminate

FIG. 1 is a schematic cross-sectional view showing the structure of a metal-clad laminate according to an embodiment of the present invention.

10: Metal layer

20: Polyimide insulating layer

21: Polyimide layer

23: Polyimide layer (P)

30: Metal clad laminate

Claims (9)

A polyimide film having a plurality of polyimide layers, wherein the polyimide film is characterized in that the following conditions (i) to (iv) are satisfied: (i) The oxygen permeability coefficient is 2.0× 10 ^-18 mol·m/m ² ·s·Pa or less; (ii) the thermal expansion coefficient is in the range of 10 ppm/K to 30 ppm/K; (iii) the dielectric loss tangent (Tanδ) at 10 GHz is 0.004 or less; and (iv) a thickness in the range of 10 μm to 100 μm; the polyimide film has a polyimide layer (P) on at least one exposed surface side, constituting the polyimide layer ( The polyimide (p) of P) contains an acid anhydride residue derived from a tetracarboxylic dianhydride component and a diamine residue derived from a diamine component, and the diamine residue contains all the diamine residues is at least 30 mol% of a diamine residue derived from a diamine compound represented by the following general formula (1),

. The polyimide film according to claim 1, wherein the diamine compound represented by the general formula (1) is 1,3-bis(4-aminophenoxy)benzene. The polyimide film according to claim 2, which contains at least 60 mol % of acid anhydride residues derived from pyromellitic dianhydride in total relative to all acid anhydride residues in the polyimide (p) and acid anhydride residues derived from 3,3',4,4'-benzophenone tetracarboxylic dianhydride. The polyimide film according to claim 1, wherein the plurality of polyimide layers comprise non-thermoplastic polyimide layers, and the non-thermoplastic polyimide layers satisfy the following conditions (1) to Condition (3): (1) The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains 50 mol% or more of monomer residues having a biphenyl skeleton in all monomer residues derived from all monomer components; (2) The thickness is in the range of 7 μm to 70 μm; and (3) The ratio of the thickness to the thickness of the entire polyimide film is 70% or more. The polyimide film according to claim 4, wherein in the non-thermoplastic polyimide layer, a diamine residue derived from a diamine component constituting the non-thermoplastic polyimide contains a content relative to all The diamine residues are 20 mol% or more of diamine residues having a biphenyl skeleton, and the acid anhydride residues derived from the tetracarboxylic dianhydride component contain 20 mol% or more of diamine residues having a biphenyl skeleton with respect to all acid anhydride residues. anhydride residues. The polyimide film according to claim 4 or 5, wherein the monomer residue having a biphenyl skeleton is a diamino residue derived from 2,2'-dimethyl-4,4'-diaminobiphenyl group and acid anhydride residue derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride. A metal-clad laminate has a metal layer and a polyimide insulating layer. In the metal-clad laminate, the polyimide insulating layer includes the polyimide film according to claim 1. A method for manufacturing a metal-clad laminate, the metal-clad laminate as claimed in claim 7, the method for manufacturing the metal-clad laminate comprising: The step of coating the polyamide acid solution on the metal layer and drying to form a single-layer or multi-layer first polyamide layer; A step of coating a solution of a polyamic acid that is a precursor of the polyimide (p) on the first polyamic acid layer, and drying to form a second polyamic acid layer; and The polyimide insulating layer is formed by imidizing the polyamic acid contained in the first polyamic acid layer and the polyamic acid contained in the second polyamic acid layer A step of. A circuit board in which the metal layer of the metal-clad laminate according to claim 7 is processed into wiring.

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