JP2021160148A - Resin film, metal-clad laminate and circuit board - Google Patents

Abstract

To provide a resin film which can reduce a transmission loss in transfer of a high frequency signal and is excellent in dimensional stability, a metal-clad laminate, and a circuit board.SOLUTION: A resin film A has a liquid crystal polymer layer L, a first adhesive layer B1 laminated on one side of the liquid crystal polymer layer L, and a second adhesive layer B2 laminated opposite to the first adhesive layer B1 of the liquid crystal polymer layer L. The first adhesive layer B1 and the second adhesive layer B2 each independently have storage elastic modulus at 50°C of 1,800 MPa or less and a maximum value of storage elastic modulus at 180-260°C of 800 MPa or less. A dielectric loss tangent at 10 GHz of the whole resin film is preferably 0.005 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to, for example, a resin film useful as a circuit board material, a metal-clad laminate using the resin film, and a circuit board.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed wiring board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even after repeated bending. The demand for Circuits) is increasing. Since FPC can be mounted three-dimensionally and at high density even in a limited space, its use is expanded to, for example, wiring of moving parts of electronic devices such as HDDs, DVDs, and smartphones, and parts such as cables and connectors. I'm doing it.

In addition to higher densities, higher performance of equipment has advanced, so it is also necessary to deal with higher densities of transmission signals. When transmitting a high-frequency signal, if the transmission loss in the transmission path is large, inconveniences such as loss of an electric signal and a long delay time of the signal occur. Therefore, it will be important to reduce transmission loss in FPC in the future. In order to support high-frequency signal transmission, it has been studied to use a liquid crystal polymer having low hygroscopicity, low dielectric constant, and low dielectric loss tangent as a dielectric layer as an FPC material.

Although the liquid crystal polymer has excellent dielectric properties, there is room for improvement in thermal properties and dimensional stability. In order to improve these characteristics, a resin film in which liquid crystal polymer layers are provided on both sides of the polyimide layer has been proposed (for example, Patent Document 1). However, there is room for improvement in the adhesiveness of the liquid crystal polymer layer to the metal foil, and it is necessary to use a metal foil having a large surface roughness in order to obtain sufficient adhesiveness. In this case, there is a concern that the transmission loss will increase. Further, a resin film in which a polyimide layer is provided on a liquid crystal polymer layer (for example, Patent Document 2) has been proposed. However, when adhering the polyimide film and the liquid crystal polymer film, surface roughening by plasma treatment is required, which complicates the manufacturing process and suppresses curling of the resin film. Therefore, the polyimide film has a small difference in coefficient of thermal expansion. It is necessary to select a liquid crystal polymer film, and the problem is that there are restrictions on the applicable materials.

Japanese Unexamined Patent Publication No. 2016-117281 Japanese Unexamined Patent Publication No. 2015-74157

An object of the present invention is to provide a resin film, a metal-clad laminate, and a circuit board, which can reduce transmission loss even in the transmission of high-frequency signals and have excellent dimensional stability.

As a result of diligent research, the present inventors have found that the above problems can be solved by forming a resin film having a sandwich structure in which a liquid crystal polymer layer is sandwiched between adhesive layers having a predetermined storage elastic modulus. completed.

The resin film of the present invention has a liquid crystal polymer layer, a first adhesive layer laminated on one side of the liquid crystal polymer layer, and a second adhesive layer laminated on the opposite side of the liquid crystal polymer layer from the first adhesive layer. It is a resin film provided with an adhesive layer.
In the resin film of the present invention, the storage elastic modulus of the first adhesive layer and the second adhesive layer at 50 ° C. is independently 1800 MPa or less, and the maximum value of the storage elastic modulus at 180 to 260 ° C. is Each is independently characterized by being 800 MPa or less.

The resin film of the present invention may have a dielectric loss tangent of 0.005 or less at 10 GHz for the entire resin film.

In the resin film of the present invention, the glass transition temperature (Tg) of each of the first adhesive layer and the second adhesive layer may be 180 ° C. or lower.

In the resin film of the present invention, the first adhesive layer and the second adhesive layer may contain polyimide as a resin component. In this case, the polyimide contains an acid anhydride residue derived from the tetracarboxylic acid anhydride component and a diamine residue derived from the diamine component, and has two terminal carboxylic acids of dimeric acid for all diamine residues. It may contain 50 mol% or more of a diamine residue derived from a diamine derived from a diamine having an acid group substituted with a primary aminomethyl group or an amino group.

The resin film of the present invention has the following relationship when the thickness of the liquid crystal polymer layer is TL, the thickness of the first adhesive layer is TB1, and the thickness of the second adhesive layer is TB2. May be good.
0.15 ≤ (TB1 + TB2) / (TL + TB1 + TB2) ≤ 0.70

The metal-clad laminate of the present invention includes a first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one surface of the first metal layer.
A second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one surface of the second metal layer.
An intermediate resin layer arranged so as to be in contact with the first insulating resin layer and the second insulating resin layer, and laminated between the first single-sided metal-clad laminate and the second single-sided metal-clad laminate. It is a metal-clad laminate provided with.
The metal-clad laminate of the present invention is characterized in that the intermediate resin layer is made of any of the above resin films.

In the metal-clad laminate of the present invention, the total thickness T1 of the first insulating resin layer, the intermediate resin layer, and the second insulating resin layer may be in the range of 50 to 500 μm, and the total thickness T1 The ratio (T2 / T1) of the thickness T2 of the intermediate resin layer to the ratio of the thickness T2 to the intermediate resin layer may be in the range of 0.50 to 0.90.

In the metal-clad laminate of the present invention, the first insulating resin layer and the second insulating resin layer both have a multilayer structure in which a thermoplastic polyimide layer, a non-thermoplastic polyimide layer, and a thermoplastic polyimide layer are laminated in this order. The intermediate resin layer may be provided in contact with the two thermoplastic polyimide layers.

In the metal-clad laminate of the present invention, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains a tetracarboxylic acid residue and a diamine residue, and is generally described below with respect to 100 mol parts of all diamine residues. The content of the diamine residue derived from the diamine compound represented by the formula (A1) may be 80 mol parts or more.

In the formula (A1), the linking group Z represents a single bond or −COO−, and Y is a monovalent hydrocarbon having 1 to 3 carbon atoms which may be independently substituted with a halogen atom or a phenyl group, or a carbon number of carbon atoms. It represents an alkoxy group of 1 to 3 or a perfluoroalkyl group or an alkenyl group having 1 to 3 carbon atoms, n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4.

The circuit board of the present invention includes a first circuit board having a first wiring layer and a first insulating resin layer laminated on at least one surface of the first wiring layer.
A second circuit board having a second wiring layer and a second insulating resin layer laminated on at least one surface of the second wiring layer.
A circuit board provided with an intermediate resin layer arranged so as to be in contact with the first insulating resin layer and the second insulating resin layer and laminated between the first circuit board and the second circuit board. Is.
The circuit board of the present invention is characterized in that the intermediate resin layer is made of any of the above resin films.

Since the resin film of the present invention has a sandwich structure in which a liquid crystal polymer layer is sandwiched between adhesive layers having a predetermined storage elastic modulus, it is excellent in dielectric properties and dimensional stability. Therefore, in the circuit board using the resin film of the present invention, it is possible to reduce the transmission loss at the time of high frequency signal transmission and to secure the dimensional stability.
Further, since the metal-clad laminate of the present invention has a structure in which two single-sided metal-clad laminates are laminated with the resin film interposed therebetween, the thickness of the insulating resin layer can be increased, and a high-frequency signal can be obtained. It is possible to reduce the transmission loss during transmission, and it is also excellent in dimensional stability.
Therefore, by using the resin film or the metal-clad laminate of the present invention, it is possible to cope with high frequency in the circuit board, and it is possible to improve the reliability and the yield.

It is a schematic diagram which shows the cross-sectional structure of the resin film of one Embodiment of this invention. It is a schematic diagram which shows the structure of the metal-clad laminate of one Embodiment of this invention. It is a schematic cross-sectional view which shows the structure of the metal-clad laminate of the preferable embodiment of this invention. It is explanatory drawing of the target for position measurement used for measuring the dimensional change rate after etching. It is explanatory drawing of the evaluation sample used for measuring the dimensional change rate after etching.

Embodiments of the present invention will be described with reference to the drawings as appropriate.

[Resin film]
FIG. 1 is a schematic view showing the configuration of the resin film A according to the embodiment of the present invention. The resin film A has a liquid crystal polymer layer L, a first adhesive layer B1 laminated on one side of the liquid crystal polymer layer L, and a second adhesive layer B laminated on the opposite side of the liquid crystal polymer layer L from the first adhesive layer B1. It includes an adhesive layer B2. The resin film A has a sandwich structure in which the liquid crystal polymer layer L is sandwiched between the first adhesive layer B1 and the second adhesive layer B2.

[Liquid crystal polymer layer]
The liquid crystal polymer layer L is a layer containing a liquid crystal polymer as a main component of the resin component, preferably 70% by weight or more of the resin component, more preferably 90% by weight or more of the resin component, and most preferably all of the resin components. All you need is. The main component of the resin component means a component contained in an amount of more than 50% by weight based on the total resin component. The liquid crystal polymer has almost no frequency dependence of the dielectric property, has a very excellent dielectric property, and also contributes to improvement of flame retardancy.

In order to improve the dielectric properties of the entire resin film A, the liquid crystal polymer layer L has a relative permittivity at 10 GHz, preferably in the range of 2 to 3.5, more preferably 2.6 to, as a simple substance. It is preferable to use one which is within the range of 3.3 and has a dielectric loss tangent of preferably less than 0.003, more preferably 0.002 or less.

The melting point of the liquid crystal polymer is preferably 280 ° C. or higher, for example. It is more preferably 290 ° C. or higher, and even more preferably 300 ° C. or higher. If the melting point is lower than 280 ° C., it may melt in the manufacturing process of electronic devices and the like, causing a change in characteristics.

The liquid crystal polymer is not particularly limited, and for example, a polyester structure such as a known thermotropic liquid crystal polyester or polyester amide derived from the compounds classified into the following (1) to (4) and their derivatives can be used. It is preferable to have.
(1) Aromatic or aliphatic dihydroxy compounds (2) Aromatic or aliphatic dicarboxylic acids (3) Aromatic hydroxycarboxylic acids (4) Aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids

As a typical example of the liquid crystal polymer obtained from these raw material compounds, it is a copolymer having two or more combinations selected from the structural units represented by the following formulas (a) to (n) and is represented by the formula (a). A copolymer containing either a structural unit or a structural unit represented by the formula (e) is preferable, and a copolymer containing the structural unit represented by the formula (a) and the structural unit represented by the formula (e) is more preferable. .. Further, as the number of aromatic rings in the liquid crystal polymer increases, the effect of improving the dielectric properties and flame retardancy can be expected. Therefore, the compound containing an aromatic dihydroxy compound as the above (1) and the aromatic dicarboxylic acid as the above (2). Is preferable.

The liquid crystal polymer layer L constituting the resin film A contains, as optional components, other resin components such as a plasticizer and an epoxy resin, a curing agent, a curing accelerator, an organic filler, an inorganic filler, a coupling agent, a flame retardant, and the like. It can be contained as appropriate.

As the liquid crystal polymer layer L, a commercially available liquid crystal polymer film can be appropriately selected and used. For example, Kuraray Co., Ltd. (trade name; Vecstar) or the like can be preferably used.

[First adhesive layer and second adhesive layer]
The first adhesive layer B1 and the second adhesive layer B2 each have an independent storage elastic modulus of 1800 MPa or less at 50 ° C., and the maximum storage elastic modulus at 180 to 260 ° C. independently of 800 MPa or less. It is preferably in the range of 500 MPa or less. By setting such a storage elastic modulus, the internal stress during thermocompression bonding is relaxed to maintain the dimensional stability after circuit processing, and warpage is unlikely to occur even after passing through the solder reflow process after circuit processing. Become.
The first adhesive layer B1 and the second adhesive layer B2 may have the same or different configurations such as thickness, physical properties, and material, but the same configuration is preferable.

In order to maintain good dielectric properties of the entire resin film A, the first adhesive layer B1 and the second adhesive layer B2 have a relative permittivity at 10 GHz, preferably in the range of 2 to 3.5, respectively. , More preferably in the range of 2 to 3, and having a dielectric loss tangent of preferably less than 0.003, more preferably 0.0025 or less.

The glass transition temperature (Tg) of each of the first adhesive layer B1 and the second adhesive layer B2 is preferably 180 ° C. or lower, more preferably 160 ° C. or lower. By setting the Tg of the first adhesive layer B1 and the second adhesive layer B2 to 180 ° C. or lower, thermocompression bonding at a low temperature becomes possible, so that the internal stress generated at the time of laminating with a metal-clad laminate or the like is relaxed. However, it is possible to suppress dimensional changes after circuit processing. When the Tg of the first adhesive layer B1 and the second adhesive layer B2 exceeds 180 ° C., the thermocompression bonding temperature when the resin film A is interposed between the metal-clad laminates and the like and bonded becomes high, and circuit processing There is a risk of impairing later dimensional stability.

The first adhesive layer B1 and the second adhesive layer B2 are preferably 70% by weight or more of the resin component, more preferably 90% by weight or more of the resin component, and most preferably all of the resin components as the main components of the resin component. It is preferable that the polyimide layer contains polyimide. The main component of the resin component means a component contained in an amount of more than 50% by weight based on the total resin component.
When the first adhesive layer B1 and the second adhesive layer B2 are polyimide layers, the polyimides constituting them are acid anhydride residues derived from the tetracarboxylic acid anhydride component and diamines derived from the diamine component. A diamine residue derived from a diamine derived from diamine, which contains a residue and has two terminal carboxylic acid groups of dimeric acid substituted with a primary aminomethyl group or an amino group, for all diamine residues. It is preferably a polyimide containing 50 mol% or more. Hereinafter, the polyimide constituting the first adhesive layer B1 and the second adhesive layer B2 may be referred to as "adhesive polyimide". In the present invention, the "tetracarboxylic acid residue" represents a tetravalent group derived from the tetracarboxylic dianhydride, and the "diamine residue" is derived from the diamine compound 2 Represents the basis of valence. When the tetracarboxylic dianhydride and the diamine compound, which are the raw materials, are reacted in approximately equimolar amounts, the types of tetracarboxylic acid residues and diamine residues contained in the polyimide are determined with respect to the type and molar ratio of the raw materials. The molar ratio can be made almost compatible.
The term "polyimide" in the present invention means a resin composed of a polymer having an imide group in its molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxaneimide, and polybenzimidazolimide, in addition to polyimide. ..

(Acid anhydride)
As the adhesive polyimide, tetracarboxylic acid anhydride generally used for thermoplastic polyimide can be used as a raw material without particular limitation, but the following general formula (1) and / or (for all tetracarboxylic acid anhydride components) It is preferable to use a raw material containing 90 mol% or more of the tetracarboxylic acid anhydride represented by 2) in total. In other words, the adhesive polyimide has a tetracarboxylic acid residue derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) with respect to all the tetracarboxylic acid residues. Is preferably contained in an amount of 90 mol% or more in total. A total of 90 mol% or more of tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) is contained in the total tetracarboxylic acid residues. This is preferable because it is easy to achieve both the flexibility and heat resistance of the adhesive polyimide. If the total of the tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) is less than 90 mol%, the solvent solubility of the adhesive polyimide is lowered. It becomes a tendency.

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 portion represented by Y is a 4-membered ring or a 5-membered ring. , 6-membered ring, 7-membered ring or 8-membered ring.

In the above formula, Z is _{-C 6 H 4 -, - (} CH 2) n- or _{-CH 2 -CH (-O-C (} = O) -CH 3) -CH 2 - are illustrated, n represents 1 Indicates an integer of ~ 20.

Examples of the tetracarboxylic acid anhydride represented by the general formula (1) include 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3', 4,4'. -Benzophenone tetracarboxylic acid anhydride (BTDA), 3,3', 4,4'-diphenylsulfone tetracarboxylic acid anhydride (DSDA), 4,4'-oxydiphthalic acid anhydride (ODPA), 4,4 '-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), p-phenylenebis (trimerit) Acid monoesteric anhydride) (TAHQ), ethylene glycol bisamhydrotrimeritate (TMEG) and the like can be mentioned. Of these, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) is particularly preferable. When BTDA is used, the carbonyl group (ketone group) contributes to the adhesiveness, so that the adhesiveness of the adhesive polyimide can be improved. Further, in BTDA, a ketone group existing in the molecular skeleton may react with an amino group of an amino compound for forming a crosslink, which will be described later, to form a C = N bond, and the effect of improving heat resistance is likely to be exhibited. .. From such a viewpoint, it is preferable to contain BTDA-derived tetracarboxylic acid residue in an amount of preferably 50 mol% or more, more preferably 60 mol% or more, based on the total tetracarboxylic acid residue.

Examples of the tetracarboxylic acid anhydride represented by the general formula (2) include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,2,3,4-cyclopentanetetracarboxylic acid. Dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,4,5-cycloheptanetetracarboxylic acid dianhydride, 1,2,5,6-cyclooctanetetracarboxylic acid Bianhydrides and the like can be mentioned.

The adhesive polyimide contains tetracarboxylic acid residues derived from acid anhydrides other than the tetracarboxylic acid anhydrides represented by the general formulas (1) and (2) above, as long as the effects of the invention are not impaired. Can be contained. Such tetracarboxylic acid residues are not particularly limited, but for example, pyromellitic acid dianhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3 , 3'-or 2,3,3', 4'-benzophenone tetracarboxylic acid dianhydride, 2,3', 3,4'-diphenyl ether tetracarboxylic acid dianhydride, bis (2,3-dicarboxyphenyl) ) Ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''-or 2,2'',3,3''-p-terphenyltetracarboxylic Acid dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) methane dianhydride, Bis (2,3- or 3,4-dicarboxyphenyl) sulfonate 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-anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-Dicarboxyphenyl) Tetrafluoropropane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid dianhydride 1,4,5,8-naphthalene tetracarboxylic acid dianhydride 2, 3,6,7-naphthalene tetracarboxylic acid dianhydride 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid 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 acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic Aromatic tetracarboxylic acid dianhydride such as acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride. Examples include tetracarboxylic acid residues derived from the substance.

(Diamine)
As the adhesive polyimide, a diamine compound generally used for thermoplastic polyimide can be used as a raw material without particular limitation, but the two terminal carboxylic acid groups of dimer acid are primary aminomethyl groups or amino groups with respect to the total diamine component. It is preferable to use a raw material containing 50 mol% or more of a diamine derived from dimer acid, which is substituted with. In other words, the adhesive polyimide is a diamine residue derived from a diamine-derived diamine in which the two terminal carboxylic acid groups of dimer acid are replaced with primary aminomethyl groups or amino groups for all diamine residues. It is preferable that the group is contained in an amount of 50 mol% or more. By containing 50 mol% or more of the diamine residue derived from the diamine derived from dimer acid, the adhesive polyimide can have a low dielectric constant and a low dielectric loss tangent, and the adhesiveness can be enhanced.

Since the diamine derived from dimer acid is a mixture containing a trimmer component and a monomer component other than the diamine diamine, it is preferable to purify and use the diamine. Hereinafter, a purified diamine derived from diamine acid may be referred to as a "diamine diamine composition". The diamine diamine composition is a purified product containing the following component (a) as a main component and in which the amounts of the components (b) and (c) are controlled.

(A) Dimer diamine;
In the diamine diamine of the component (a), the two terminal carboxylic acid groups (-COOH) of the dimer acid are replaced with _{a primary aminomethyl group (-CH 2-} NH ₂ ) or an amino group (-NH _2). It means diamine. Dimeric acid is a known dibasic acid obtained by the intermolecular polymerization reaction of unsaturated fatty acids, and its industrial production process is almost standardized in the industry, and unsaturated fatty acids having 11 to 22 carbon atoms are clay-catalyzed. It is obtained by quantifying it with or the like. The industrially obtained dimer acid is mainly composed of a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linolenic acid and linolenic acid. Depending on the degree, it contains an arbitrary amount of monomeric acid (18 carbon atoms), trimeric acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. Further, although the double bond remains after the dimerization reaction, in the present invention, the dimer acid is also included in which the degree of unsaturation is lowered by the hydrogenation reaction. The dimer diamine of the component (a) is prepared by substituting a primary aminomethyl group or an amino group for the terminal carboxylic acid group of the dibasic acid compound in the range of 18 to 54 carbon atoms, preferably 22 to 44 carbon atoms. It can be defined as the resulting diamine compound.

As a characteristic of dimer diamine, it is possible to impart properties derived from the skeleton of dimer acid. That is, since dimer diamine is an aliphatic of macromolecules having a molecular weight of about 560 to 620, the molar volume of the molecule can be increased and the polar groups of polyimide can be relatively reduced. It is considered that such a feature of the dimer diamine contributes to improving the dielectric property by reducing the relative permittivity and the dielectric loss tangent while suppressing the decrease in the heat resistance of the polyimide. Further, since it has two free-moving hydrophobic chains having 7 to 9 carbon atoms and two chain-like aliphatic amino groups having a length close to 18 carbon atoms, it not only gives flexibility to the polyimide, but also gives the polyimide flexibility. Since the polyimide can have an asymmetrical chemical structure or a non-planar chemical structure, it is considered that the polyimide can have a low dielectric constant.

The diamine diamine composition used is such that the diamine diamine content of the component (a) is increased to 96% by weight or more, preferably 97% by weight or more, more preferably 98% by weight or more by a purification method such as molecular distillation. That is good. By setting the diamine diamine content of the component (a) to 96% by weight or more, it is possible to suppress the spread of the molecular weight distribution of polyimide. If technically possible, it is best that all (100% by weight) of the diamine diamine composition is composed of the diamine diamine of the component (a).

(B) A monoamine compound obtained by substituting a terminal carboxylic acid group of a monobasic acid compound having 10 to 40 carbon atoms with a primary aminomethyl group or an amino group;
The monobasic acid compound in the range of 10 to 40 carbon atoms is a monobasic unsaturated fatty acid in the range of 10 to 20 carbon atoms derived from the raw material of dimer acid, and a by-product during the production of dimer acid. It is a mixture of monobasic acid compounds in the range of 21 to 40 carbon atoms. The monoamine compound is obtained by substituting the terminal carboxylic acid group of these monobasic acid compounds with a primary aminomethyl group or an amino group.

The monoamine compound of the component (b) is a component that suppresses an increase in the molecular weight of polyimide. During the polymerization of polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of the polyamic acid or polyimide to seal the terminal acid anhydride group, and the molecular weight of the polyamic acid or polyimide is sealed. Suppress the increase.

(C) An amine compound obtained by substituting a primary aminomethyl group or an amino group for a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms (however, the dimerdiamine). except for);
The polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms is mainly composed of a tribasic acid compound in the range of 41 to 80 carbon atoms, which is a by-product during the production of dimer acid. It is a polybasic acid compound. Further, it may contain a polymerized fatty acid other than dimer acid having 41 to 80 carbon atoms. The amine compound is obtained by substituting the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

The amine compound of the component (c) is a component that promotes an increase in the molecular weight of polyimide. A trifunctional or higher amino group containing a triamine derived from trimeric acid as a main component reacts with a polyamic acid or a terminal acid anhydride group of polyimide to rapidly increase the molecular weight of polyimide. Further, an amine compound derived from a polymerized fatty acid other than dimer acid having 41 to 80 carbon atoms also increases the molecular weight of the polyimide and causes gelation of the polyamic acid or the polyimide.

When quantifying each component by measurement using gel permeation chromatography (GPC), diamine diamine composition is used to facilitate confirmation of peak start, peak top and peak end of each component of the diamine diamine composition. Samples treated with acetic anhydride and pyridine are used and cyclohexanone is used as an internal standard. Using the sample prepared in this way, each component is quantified by the area percentage of the GPC chromatogram. The peak start and peak end of each component are set to the minimum value of each peak curve, and the area percentage of the chromatogram can be calculated based on this.

Further, the diamine diamine composition is preferably an area percentage of the chromatogram obtained by GPC measurement, and the total of the components (b) and (c) is 4% or less, preferably less than 4%. By setting the total of the components (b) and (c) to 4% or less, it is possible to suppress the spread of the molecular weight distribution of the polyimide.

The area percentage of the chromatogram of the component (b) is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less. By setting the range to such a range, it is possible to suppress a decrease in the molecular weight of the polyimide, and further expand the range of the molar ratio of the tetracarboxylic dianhydride component and the diamine component to be charged. The component (b) does not have to be contained in the diamine diamine composition.

The area percentage of the chromatogram of the component (c) is 2% or less, preferably 1.8% or less, and more preferably 1.5% or less. Within such a range, a rapid increase in the molecular weight of the polyimide can be suppressed, and an increase in the dielectric loss tangent of the resin film at a wide frequency range can be suppressed. The component (c) does not have to be contained in the diamine diamine composition.

When the area-percentage ratio (b / c) of the chromatograms of the components (b) and (c) is 1 or more, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component / The diamine component) is preferably 0.97 or more and less than 1.0, and such a molar ratio makes it easier to control the molecular weight of the polyimide.

When the area-percentage ratio (b / c) of the components (b) and (c) of the chromatogram is less than 1, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component). The / diamine component) is preferably 0.97 or more and 1.1 or less, and such a molar ratio makes it easier to control the molecular weight of the polyimide.

As the diamine derived from dimer acid, a commercially available product can be used, and it is preferable to purify the diamine for the purpose of reducing the components other than the diamine diamine of the component (a). For example, the component (a) should be 96% by weight or more. Is preferable. The purification method is not particularly limited, but a known method such as a distillation method or precipitation purification is preferable. Examples of commercially available products of diamines derived from dimer acid include PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Croda Japan.

The adhesive polyimide may contain a diamine residue derived from a diamine component other than the above. As such a diamine residue, for example, a diamine residue derived from a diamine compound represented by the general formulas (B1) to (B7) is preferable.

In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents -O-, -S-, and -CO-. , -SO-, -SO _2- , -COO-, -CH _2- , -C (CH ₃ ) _2- , -NH- or -CONH-, indicating a divalent group, n ₁ being independent. Indicates an integer from 0 to 4. However, the formula (B3) that overlaps with the formula (B2) is excluded, and the formula (B5) that overlaps with the formula (B4) is excluded. Here, "independently", in one of the above formulas (B1) ~ (B7), or in two or more, a plurality of linking groups A, a plurality of R ₁ or a plurality of n _1, the same However, it means that it may be different. In the above formulas (B1) to (B7), the hydrogen atom in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ are independent. It may mean any substituent such as an alkyl group).

The diamine represented by the formula (B1) (hereinafter, may be referred to as "diamine (B1)") is an aromatic diamine having two benzene rings. This diamine (B1) has a high degree of flexibility due to an increase in the degree of freedom of the polyimide molecular chain by having an amino group directly linked to at least one benzene ring and a divalent linking group A at the meta position. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B1) enhances the thermoplasticity of the polyimide. Here, as the linking group A, -O-, -CH _2- , -C (CH ₃ ) _2- , -CO-, -SO _2- , -S- are preferable.

Examples of the diamine (B1) include 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, and 3,3'-diamino. Diphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenylsulfide, 3,3'-diaminobenzophenone, (3,3'- Bisamino) diphenylamine and the like can be mentioned.

The diamine represented by the formula (B2) (hereinafter, may be referred to as "diamine (B2)") is an aromatic diamine having three benzene rings. This diamine (B2) has a high degree of flexibility due to an increase in the degree of freedom of the polyimide molecular chain by having an amino group directly linked to at least one benzene ring and a divalent linking group A at the meta position. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B2) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B2) include 1,4-bis (3-aminophenoxy) benzene, 3- [4- (4-aminophenoxy) phenoxy] benzeneamine, and 3- [3- (4-aminophenoxy) phenoxy]. Benzene amine and the like can be mentioned.

The diamine represented by the formula (B3) (hereinafter, may be referred to as "diamine (B3)") is an aromatic diamine having three benzene rings. This diamine (B3) has two divalent linking groups A directly linked to one benzene ring at the meta position of each other, so that the degree of freedom of the polyimide molecular chain is increased and the diamine has high flexibility. Therefore, it is considered that it contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B3) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B3) include 1,3-bis (4-aminophenyloxy) benzene (TPE-R), 1,3-bis (3-aminophenoxy) benzene (APB), and 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) ) Benzene] Bisaniline and the like can be mentioned.

The diamine represented by the formula (B4) (hereinafter, may be referred to as "diamine (B4)") is an aromatic diamine having four benzene rings. This diamine (B4) has high flexibility because the amino group directly linked to at least one benzene ring and the divalent linking group A are in the meta position, which improves the flexibility of the polyimide molecular chain. It is thought to contribute. Therefore, the use of diamine (B4) enhances the thermoplasticity of the 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, and bis. Examples thereof include [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy)] benzophenone, and bis [4,4'-(3-aminophenoxy)] benzanilide.

The diamine represented by the formula (B5) (hereinafter, may be referred to as "diamine (B5)") is an aromatic diamine having four benzene rings. This diamine (B5) has two divalent linking groups A directly linked to at least one benzene ring at the meta position of each other, so that the degree of freedom of the polyimide molecular chain is increased and the diamine has high flexibility. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B5) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

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

The diamine represented by the formula (B6) (hereinafter, may be referred to as "diamine (B6)") is an aromatic diamine having four benzene rings. This diamine (B6) has high flexibility by having at least two ether bonds, and is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B6) enhances the thermoplasticity of the 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). -(4-Aminophenoxy) phenyl] sulfone (BAPS), bis [4- (4-aminophenoxy) phenyl] ketone (BAPK) and the like can be mentioned.

The diamine represented by the formula (B7) (hereinafter, may be referred to as "diamine (B7)") is an aromatic diamine having four benzene rings. Since this diamine (B7) has highly flexible divalent linking groups A on both sides of the diphenyl skeleton, it is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B7) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

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

The adhesive polyimide contains a diamine residue derived from at least one diamine compound selected from diamine (B1) to diamine (B7), preferably 1 mol% or more and 50 mol% or less, based on all diamine residues. It is preferably contained within the range, more preferably within the range of 5 mol% or more and 35 mol% or less. Since diamines (B1) to diamines (B7) have a flexible molecular structure, the flexibility of the polyimide molecular chain is improved by using at least one diamine compound selected from these in an amount within the above range. And can impart thermoplasticity.

The adhesive polyimide can further contain diamine residues other than the above as long as the effects of the invention are not impaired.

The adhesive polyimide can be produced by reacting the above-mentioned acid anhydride component and diamine component in a solvent to generate polyamic acid, and then heat-closing the ring. For example, the acid anhydride component and the diamine component are dissolved in an organic solvent in approximately equimolar amounts, and the mixture is stirred at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours to carry out a polymerization reaction to obtain a polyimide precursor. Polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the precursor produced is in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight. Examples of the organic solvent 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, dimethylsulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglime, triglime, methanol, ethanol, benzyl alcohol, cresol and the like can be mentioned. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can be used in combination. The amount of such an organic solvent used is not particularly limited, but it should be adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight. Is preferable.

The synthesized polyamic acid is usually advantageous to be used as a reaction solvent solution, but can be concentrated, diluted or replaced with another organic solvent if necessary. In addition, polyamic acid is generally excellent in solvent solubility, and is therefore advantageously used. The viscosity of the polyamic acid solution is preferably in the range of 500 mPa · s to 100,000 mPa · s. If it is out of this range, defects such as thickness unevenness and streaks are likely to occur in the film during coating work by a coater or the like.

The method of imidizing the polyamic acid to form the polyimide is not particularly limited, and for example, a heat treatment such as heating in the solvent under a temperature condition in the range of 80 to 400 ° C. for 1 to 24 hours is preferably adopted. Will be done. Further, the temperature may be heated under a constant temperature condition, or the temperature may be changed in the middle of the process.

In the adhesive polyimide, the dielectric properties, the coefficient of thermal expansion, and the coefficient of thermal expansion can be determined by selecting the types of the acid anhydride component and the diamine component and the molar ratio of each when two or more kinds of the acid anhydride component or the diamine component are applied. Physical properties such as tensile elastic modulus and glass transition temperature can be controlled. When the adhesive polyimide has a plurality of structural units, it may exist as a block or randomly, but it is preferable that the adhesive polyimide exists randomly.

The weight average molecular weight of the adhesive polyimide is preferably in the range of 10,000 to 400,000, more preferably in the range of 50,000 to 350,000. If the weight average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased, and defects such as film thickness unevenness and streaks tend to occur during the coating operation.

(Crosslink formation of adhesive polyimide)
When the adhesive polyimide has a ketone group, a crosslinked structure can be formed by reacting the ketone group with a crosslinking agent having a functional group that undergoes a nucleophilic addition reaction. Heat resistance can be improved by forming a crosslinked structure. A polyimide having such a crosslinked structure (hereinafter, may be referred to as “crosslinked polyimide”) is an application example of an adhesive polyimide, and is in a preferable form.

As the cross-linking agent, for example, it is preferable to use an amino compound having at least two primary amino groups as a functional group (hereinafter, may be referred to as “cross-linking amino compound”). A crosslinked structure can be formed by reacting the ketone group of the adhesive polyimide with the amino group of the crosslink-forming amino compound to form a C = N bond. That is, the two primary amino groups in the amino compound function as functional groups that undergo a nucleophilic addition reaction with the ketone group.

Preferred tetracarboxylic acid anhydrides for forming an adhesive polyimide having a ketone group include, for example, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), and diamine compounds include, for example. Aromatic diamines such as 4,4'-bis (3-aminophenoxy) benzophenone (BABP) and 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) can be mentioned. For the purpose of forming a crosslinked structure, particularly, the above-mentioned adhesiveness containing BTDA residue derived from BTDA in an amount of preferably 50 mol% or more, more preferably 60 mol% or more, based on all tetracarboxylic acid residues. It is preferable to allow the crosslink-forming amino compound to act on the polyimide. In the present invention, the "BTDA residue" means a tetravalent group derived from BTDA.

Examples of the crosslink-forming amino compound include (I) a dihydrazide compound, (II) an aromatic diamine, and (III) an aliphatic amine. Among these, a dihydrazide compound is preferable. Aliphatic amines other than dihydrazide compounds tend to form crosslinked structures even at room temperature, and there is a concern about storage stability of varnishes, while aromatic diamines need to be heated to a high temperature in order to form crosslinked structures. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the shortening of the curing time can be achieved at the same time. Examples of the dihydrazide compound include dihydrazide oxalic acid, dihydrazide malonate, dihydrazide succinic acid, dihydrazide glutalide, adipic acid dihydrazide, dihydrazide dihydric acid, dihydrazide dihydranoate, dihydrazide azelaide, dihydrazide sebacic acid, and dihydrazide sevacinate. Dihydrazide, dihydrazide fumarate, diglycolic acid dihydrazide, tartrate dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoediic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4 Dihydrazide compounds such as −naphthoic acid dihydrazide, 2,6-pyridinediic acid dihydrazide, and itaconic acid dihydrazide are preferred. The above dihydrazide compounds may be used alone or in combination of two or more.

Further, the amino compounds such as (I) dihydrazide compound, (II) aromatic diamine, and (III) aliphatic amine are, for example, a combination of (I) and (II), a combination of (I) and (III), and the like. It is also possible to use two or more types in combination across categories, such as the combination of (I), (II) and (III).

Further, from the viewpoint of making the network structure formed by cross-linking with the cross-linking amino compound more dense, the cross-linking amino compound used in the present invention has a molecular weight (when the cross-linking amino compound is an oligomer). The weight average molecular weight) is preferably 5,000 or less, more preferably 90 to 2,000, and even more preferably 100 to 1,500. Among these, an amino compound for cross-linking having a molecular weight of 100 to 1,000 is particularly preferable. When the molecular weight of the cross-linking amino compound is less than 90, only one amino group of the cross-linking amino compound forms a C = N bond with the ketone group of the adhesive polyimide, and the periphery of the remaining amino groups is steric. Since it becomes bulky, the remaining amino groups tend to be difficult to form a C = N bond.

When cross-linking a ketone group in an adhesive polyimide and an amino compound for forming a bridge, the above amino compound for cross-linking is added to a resin solution containing the adhesive polyimide to form a cross-linking with the ketone group in the adhesive polyimide. Condensation reaction with the primary amino group of the amino compound for use. By this condensation reaction, the resin solution is cured to become a cured product. In this case, the amount of the amino compound for forming a bridge is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, in total of the primary amino group with respect to 1 mol of the ketone group. It can be more preferably 0.03 mol to 0.9 mol, and most preferably 0.04 mol to 0.6 mol. If the amount of the cross-linking amino compound added so that the total number of primary amino groups is less than 0.004 mol with respect to 1 mol of the ketone group, the cross-linking by the cross-linking amino compound is not sufficient, and therefore after curing. Heat resistance tends to be difficult to develop, and when the amount of the cross-linking amino compound added exceeds 1.5 mol, the unreacted cross-linking amino compound acts as a thermoplastic agent, and the heat resistance as the adhesive layer is lowered. Tends to let.

The ketone group in the adhesive polyimide and the functional group of the cross-linking agent are subjected to a nucleophilic addition reaction to form a cross-link, and the cross-linked polyimide is obtained as a cured product. The conditions of the nucleophilic addition reaction for cross-linking are not particularly limited and can be selected according to the type of cross-linking agent. For example, when the primary amino group of the cross-linking amino compound is reacted with the ketone group in the adhesive polyimide, an imine bond (C = N bond) is formed by a condensation reaction by heating to form a cross-linked structure. The conditions of the condensation reaction for crosslink formation are not particularly limited as long as the ketone group in the adhesive polyimide and the primary amino group of the crosslink forming amino compound form an imine bond (C = N bond). .. The temperature of the heat condensation is, for example, 120 for the purpose of releasing the water generated by the condensation to the outside of the system, or for simplifying the condensation step when the heat condensation reaction is subsequently carried out after the synthesis of the adhesive polyimide. The range of about 220 ° C. is preferable, and the range of 140 to 200 ° C. is more preferable. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction is the absorption derived from the ketone group in the polyimide resin near ^{1670 cm-1} by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by JASCO Corporation). It can be confirmed by the decrease or disappearance of the peak and the appearance of the absorption peak derived from the imine group near ^{1635 cm-1.}

The thermal condensation of the ketone group of the adhesive polyimide and the primary amino group of the above-mentioned cross-linking amino compound is, for example,
(1) A method of adding an amino compound for cross-linking and heating following the synthesis (imidization) of adhesive polyimide.
(2) An excess amount of an amino compound is charged in advance as a diamine component, and following the synthesis (imidization) of the adhesive polyimide, the remaining amino compound that is not involved in imidization or amidization is used as an amino compound for cross-linking formation. And heating with adhesive polyimide,
Or
(3) A method of heating an adhesive polyimide composition to which the above-mentioned crosslink-forming amino compound is added after processing it into a predetermined shape (for example, after applying it to an arbitrary substrate or forming it into a film).
It can be done by such as.

In order to impart heat resistance to the adhesive polyimide, an example of a crosslinked polyimide having a crosslinked structure by forming an imine bond has been described, but the present invention is not limited to this, and examples of the polyimide curing method include epoxy resin and epoxy. It is also possible to blend and cure a compound having an unsaturated bond such as a resin curing agent, maleimide, an activated ester resin, or a resin having a styrene skeleton.

The first adhesive layer B1 and the second adhesive layer B2 constituting the resin film A have optional components such as other resin components such as a plasticizer and an epoxy resin, a curing agent, a curing accelerator, and an organic filler. An inorganic filler, a coupling agent, a flame retardant, and the like can be appropriately contained.

When the resin film A is applied to a circuit board, for example, the dielectric loss tangent (Tanδ) at 10 GHz is preferably 0.005 or less, more preferably 0.0035 or less, still more preferably 0.0035 or less, in order to suppress deterioration of dielectric loss. Should be 0.0025 or less. If the dielectric loss tangent of the resin film A at 10 GHz exceeds 0.005, inconveniences such as loss of electric signals are likely to occur on the transmission path of high frequency signals when applied to a circuit board. On the other hand, the lower limit of the dielectric loss tangent of the resin film A at 10 GHz is not particularly limited.

When the resin film A is applied to a circuit board, for example, the relative permittivity at 10 GHz is preferably 4.0 or less, more preferably 3.5 or less, in order to ensure impedance matching. It is more preferably 3.0 or less. If the relative permittivity of the resin film A at 10 GHz exceeds 4.0, it leads to deterioration of the dielectric loss of the resin film A when applied to a circuit board, resulting in inconvenience such as loss of an electric signal on the transmission path of a high frequency signal. Is likely to occur.

The resin film A preferably has the following relationship when the thickness of the liquid crystal polymer layer L is TL, the thickness of the first adhesive layer B1 is TB1, and the thickness of the second adhesive layer B2 is TB2.
0.15 ≤ (TB1 + TB2) / (TL + TB1 + TB2) ≤ 0.70
If the ratio of the total thickness of the first adhesive layer B1 and the second adhesive layer B2 to the total thickness of the resin film A is less than 0.15, the dimensional change rate after heating becomes large and the dimensional stability is impaired. If it is larger than 0.70, it becomes difficult to obtain the effect of improving the dielectric properties of the entire resin film A by the liquid crystal polymer.
Here, the thickness TL of the liquid crystal polymer layer L is not particularly limited, but is preferably in the range of, for example, 25 to 250 μm, and more preferably in the range of 50 to 100 μm. The thickness TB1 of the first adhesive layer B1 and the thickness TB2 of the second adhesive layer B2 are not particularly limited, but are preferably in the range of, for example, 1 to 100 μm, and are preferably in the range of 5 to 50 μm, respectively. Is more preferable.

The resin film A may be a film (sheet) composed of a liquid crystal polymer layer L, a first adhesive layer B1 and a second adhesive layer B2, and may be a base material of an inorganic material such as a copper foil or a glass plate. Alternatively, it may be in a state of being laminated on a resin base material such as a polyimide film, a polyamide film, or a polyester film.

The method for producing the resin film A of the present embodiment is not particularly limited, but for example, when the first adhesive layer B1 and the second adhesive layer B2 are polyimide layers made of adhesive polyimide, the following [ The methods 1] to [3] can be mentioned.
[1] An adhesive polyimide is applied to one side of a liquid crystal polymer film in a solution state (for example, in the state of a polyimide composition) to form a coating film, which is dried at a temperature of, for example, 80 to 180 ° C. A method in which a coating film made of adhesive polyimide is similarly formed on the other side surface, and the resin film A is formed by heating and drying.
[2] A solution of polyamic acid, which is a precursor of adhesive polyimide, is applied to an arbitrary base material, dried, imidized to form a film, and then peeled off from the base material. A method of forming a resin film A by sandwiching a liquid crystal polymer film between two polyimide films thus obtained and thermocompression bonding.
[3] A solution of polyamic acid, which is a precursor of adhesive polyimide, is applied to and dried on an arbitrary base material, and then the polyamic acid gel film is peeled off from the base material. A method in which a liquid crystal polymer film is sandwiched between two gel films thus obtained and thermocompression bonded to form a resin film A at the same time as imidization.
The method of applying the adhesive polyimide solution (or polyamic acid solution) on the substrate is not particularly limited, and for example, it can be applied with a coater such as a comma, a die, a knife, or a lip.

The resin film A obtained as described above has a sandwich structure in which the liquid crystal polymer layer L is sandwiched between the first adhesive layer B1 and the second adhesive layer B2 having a predetermined storage elastic modulus. Excellent dimensional stability. Therefore, the resin film A can be preferably applied as, for example, an adhesive film (bonding sheet), an adhesive layer forming a part of an insulating resin layer of a circuit board, or the like. By applying the resin film A, it is possible to reduce the transmission loss at the time of high-frequency signal transmission in the circuit board, and it is possible to secure the dimensional stability.

[Metal-clad laminate]
FIG. 2 is a schematic view showing the configuration of a metal-clad laminate according to an embodiment of the present invention. The metal-clad laminate (C) of the present embodiment has a structure in which a pair of single-sided metal-clad laminates are bonded by an adhesive layer (A').
That is, the metal-clad laminate (C) includes a first single-sided metal-clad laminate (C1), a second single-sided metal-clad laminate (C2), these first single-sided metal-clad laminate (C1), and the like. An adhesive layer (A') laminated between the second single-sided metal-clad laminates (C2) is provided. Here, the adhesive layer (A') is made of the resin film A.

Further, the first single-sided metal-clad laminate (C1) includes a first metal layer (M1) and a first insulating resin layer (M1) laminated on at least one surface of the first metal layer (M1). P1) and. The second single-sided metal-clad laminate (C2) is a second metal layer (M2) and a second insulating resin layer (P2) laminated on at least one surface of the second metal layer (M2). And have. The adhesive layer (A') is arranged so as to abut the first insulating resin layer (P1) and the second insulating resin layer (P2). That is, the metal-clad laminate (C) is the first metal layer (M1) / first insulating resin layer (P1) / adhesive layer (A') / second insulating resin layer (P2) / second. It has a structure in which metal layers (M2) are laminated in this order. The first metal layer (M1) and the second metal layer (M2) are located on the outermost side, respectively, and the first insulating resin layer (P1) and the second insulating resin layer (P2) are located inside them. An adhesive layer (A') is interposed between the first insulating resin layer (P1) and the second insulating resin layer (P2).

The configuration of the pair of single-sided metal-clad laminates (C1, C2) is not particularly limited, and a general FPC material can be used, and a commercially available copper-clad laminate may be used. The configurations of the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) may be the same or different.

(Metal layer)
The materials of the first metal layer (M1) and the second metal layer (M2) are not particularly limited, but for example, copper, stainless steel, iron, nickel, berylium, aluminum, zinc, indium, silver, gold, and the like. Examples thereof include tin, zirconium, tantalum, titanium, lead, magnesium, manganese and alloys thereof. Of these, copper or copper alloys are particularly preferable. The material of the wiring layer in the circuit board of the present embodiment described later is also the same as that of the first metal layer (M1) and the second metal layer (M2).

The thickness of the first metal layer (M1) and the second metal layer (M2) is not particularly limited, but when a metal foil such as a copper foil is used, it is preferably 35 μm or less, more preferably. The range of 5 to 25 μm is preferable. From the viewpoint of production stability and handleability, the lower limit of the thickness of the metal foil is preferably 5 μm. When a copper foil is used, it may be a rolled copper foil or an electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

Further, the metal foil may be subjected to surface treatment with, for example, siding, aluminum alcoholate, aluminum chelate, silane coupling agent or the like for the purpose of rust prevention treatment or improvement of adhesive strength.

(Insulating resin layer)
The first insulating resin layer (P1) and the second insulating resin layer (P2) are not particularly limited as long as they are composed of a resin having electrical insulating properties, and are, for example, polyimide, epoxy resin, and phenol resin. , Polyethylene, Polyethylene, Polytetrafluoroethylene, Silicone, ETFE and the like, but it is preferably composed of polyimide. Further, the first insulating resin layer (P1) and the second insulating resin layer (P2) are not limited to a single layer, and may be a stack of a plurality of resin layers. When the term polyimide is used in the present invention, in addition to polyimide, polyamideimide, polyetherimide, polyesterimide, etc.
It means a resin composed of a polymer having an imide group in its molecular structure, such as polysiloxaneimide and polybenzimidazoleimide.

<Layer thickness>
The metal-clad laminate (C) has a total thickness T1 of 50, where T1 is the total thickness of the first insulating resin layer (P1), the adhesive layer (A'), and the second insulating resin layer (P2). It is in the range of ~ 500 μm, and preferably in the range of 100 to 300 μm. If the total thickness T1 is less than 50 μm, the effect of reducing the transmission loss when the circuit board is used is insufficient, and if it exceeds 500 μm, the flexibility of the circuit board and the productivity may be lowered.

Further, the thickness T2 of the adhesive layer (A') (that is, TL + TB1 + TB2 in the resin film A) is preferably in the range of 26 to 350 μm, more preferably in the range of 30 to 250 μm. If the thickness T2 of the adhesive layer (A') does not reach the above lower limit value, the transmission loss may increase as a high frequency substrate. On the other hand, if the thickness of the adhesive layer (A') exceeds the above upper limit value, problems such as deterioration of dimensional stability may occur.

The ratio (T2 / T1) of the thickness T2 of the adhesive layer (A') to the total thickness T1 is in the range of 0.50 to 0.90 and in the range of 0.5 to 0.8. Is preferable. If the ratio (T2 / T1) is less than 0.5, it becomes difficult to set T1 to 50 μm or more, and the effect of reducing the transmission loss when used as a circuit board becomes insufficient. If the ratio exceeds 0.90, the dimensions are stable. Problems such as reduced sexuality occur.

The thickness T3 of the first insulating resin layer (P1) and the second insulating resin layer (P2) is preferably in the range of, for example, 12 to 100 μm, and more preferably in the range of 12 to 50 μm. If the thickness T3 of the first insulating resin layer (P1) and the second insulating resin layer (P2) does not reach the above lower limit value, problems such as warpage of the metal-clad laminate (C) may occur. If the thickness T3 of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds the above upper limit value, problems such as a decrease in productivity occur. The first insulating resin layer (P1) and the second insulating resin layer (P2) do not necessarily have to have the same thickness.

<Coefficient of thermal expansion>
The first insulating resin layer (P1) and the second insulating resin layer (P2) preferably have a coefficient of thermal expansion (CTE) of 10 ppm / K or more, preferably 10 ppm / K or more and 30 ppm / K or less. It is preferably in the range of 15 ppm / K or more and 25 ppm / K or less. If the CTE is less than 10 ppm / K or more than 30 ppm / K, warpage will occur and dimensional stability will decrease. A polyimide layer having a desired CTE can be obtained by appropriately changing the combination of raw materials used, the thickness, and the drying / curing conditions.

Since the first adhesive layer B1 and the second adhesive layer B2 have low elasticity and a low glass transition temperature, even if the CTE of the entire adhesive layer (A') exceeds 30 ppm / K, the internal stress generated during lamination is generated. Can be alleviated. The overall coefficient of thermal expansion (CTE) of the first insulating resin layer (P1), the adhesive layer (A') and the second insulating resin layer (P2) is preferably 10 ppm / K or more, preferably 10 ppm / K. It is in the range of K or more and 30 ppm / K or less, more preferably in the range of 15 ppm / K or more and 25 ppm / K or less. If the CTE of the entire resin layer is less than 10 ppm / K or more than 30 ppm / K, warpage occurs or dimensional stability is lowered.

<Dissipation factor>
The first insulating resin layer (P1) and the second insulating resin layer (P2) each have a dielectric loss tangent (Tan δ) at 10 GHz in order to suppress deterioration of dielectric loss when applied to a circuit board, for example. , Preferably 0.02 or less, more preferably 0.01 or less, still more preferably 0.008 or less. When the dielectric loss tangent of the first insulating resin layer (P1) and the second insulating resin layer (P2) at 10 GHz exceeds 0.02, when applied to a circuit board, the electric signal is transmitted on the transmission path of the high frequency signal. Inconveniences such as loss are likely to occur. On the other hand, the lower limit of the dielectric loss tangent at 10 GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) is not particularly limited, but the physical property control as the insulating resin layer of the circuit board is taken into consideration. ..

<Relative permittivity>
When the first insulating resin layer (P1) and the second insulating resin layer (P2) are applied as, for example, an insulating resin layer of a circuit board, the insulating resin layer as a whole is 10 GHz in order to ensure impedance matching. The relative permittivity in is preferably 4.0 or less. When the relative dielectric constant of the first insulating resin layer (P1) and the second insulating resin layer (P2) at 10 GHz exceeds 4.0, the first insulating resin layer (P1) is applied to a circuit board. Further, it leads to deterioration of the dielectric loss of the second insulating resin layer (P2), and inconvenience such as loss of an electric signal is likely to occur on the transmission path of the high frequency signal.

<Action>
In the metal-clad laminate (C), a liquid crystal polymer layer L is provided on the adhesive layer (A') in order to reduce the dielectric loss tangent of the entire insulating resin layer and to support high-frequency signal transmission. However, since the liquid crystal polymer layer L has a large dimensional change rate before and after heating, the dimensional stability may decrease as the layer thickness of the liquid crystal polymer layer L increases.

Therefore, in the metal-clad laminate (C) of the present embodiment, the liquid crystal polymer layer L is sandwiched between the first adhesive layer B1 and the second adhesive layer B2 having a low storage elastic modulus as the adhesive layer (A'). The sandwich structure relaxes the internal stress caused by heating and ensures dimensional stability. In particular, as the material of the first adhesive layer B1 and the second adhesive layer B2, it is derived from a diamine derived from diamine in which two terminal carboxylic acid groups of dimer acid are replaced with a primary aminomethyl group or an amino group. When a polyimide containing 50 mol% or more of the diamine residue is used, the dimensional stability can be improved without increasing the relative permittivity and the dielectric tangent of the entire adhesive layer (A').

Further, since the adhesive layer (A') is laminated between the first insulating resin layer (P1) and the second insulating resin layer (P2), it functions as an intermediate layer, and has warpage and dimensions. Suppress change. Further, even in a heating process such as solder reflow during mounting of a semiconductor chip, direct contact with heat or oxygen is blocked by the first insulating resin layer (P1) or the second insulating resin layer (P2). Therefore, the adhesive layer (A') is not easily affected by oxidative deterioration and the dimensional change is unlikely to occur. As described above, it also has an advantage due to the characteristics of the layer structure of the first insulating resin layer (P1), the adhesive layer (A'), and the second insulating resin layer (P2).

[Manufacturing of metal-clad laminates]
The metal-clad laminate (C) includes, for example, a resin film A to be an adhesive layer (A'), a first insulating resin layer (P1) of the first single-sided metal-clad laminate (C1), and a second single-sided. It can be manufactured by a method of arranging and bonding the metal-clad laminate (C2) with the second insulating resin layer (P2) and thermocompression bonding.

The metal-clad laminate (C) of the present embodiment obtained as described above is subjected to wiring circuit processing by etching the first metal layer (M1) and / or the second metal layer (M2). Thereby, a circuit board such as a single-sided FPC or a double-sided FPC can be manufactured.

[Preferable configuration example of metal-clad laminate]
Next, the first insulating resin layer (P1), the second insulating resin layer (P2), the adhesive layer (A'), and the first metal layer (M1) in the metal-clad laminate (C) of the present embodiment. ) And the second metal layer (M2) will be described more specifically.

FIG. 3 is a schematic cross-sectional view showing the structure of the metal-clad laminate 100 of the present embodiment. As shown in FIG. 3, the metal-clad laminate 100 includes metal layers 101 and 101 as a first metal layer (M1) and a second metal layer (M2), a first insulating resin layer (P1), and a metal-clad laminate 100. The polyimide layers 110 and 110 as the second insulating resin layer (P2) and the adhesive layer 120 as the adhesive layer (A') are provided. Here, the metal layer 101 and the polyimide layer 110 form a single-sided metal-clad laminate 130 as a first single-sided metal-clad laminate (C1) or a second single-sided metal-clad laminate (C2). In this embodiment, the configuration of the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) are the same.

Each of the polyimide layers 110 and 110 may have a structure in which a plurality of polyimide layers are laminated. For example, in the embodiment shown in FIG. 3, the base layer is composed of non-thermoplastic polyimide layers 111 and 111 made of non-thermoplastic polyimide and thermoplastic polyimides provided on both sides of the non-thermoplastic polyimide layers 111 and 111, respectively. It has a three-layer structure including thermoplastic polyimide layers 112 and 112. The polyimide layers 110 and 110 are not limited to the three-layer structure, respectively.

In the metal-clad laminate 100 shown in FIG. 3, the outer thermoplastic polyimide layers 112 and 112 of the two single-sided metal-clad laminates 130 and 130 are respectively bonded to the adhesive layer 120 to form the metal-clad laminate 100. There is. The adhesive layer 120 is an adhesive layer for bonding two single-sided metal-clad laminates 130 and 130 in the metal-clad laminate 100, and is an insulating resin of the metal-clad laminate 100 while ensuring dimensional stability. It is for thickening the layer. The adhesive layer 120 is as described above for the adhesive layer (A').

Next, the non-thermoplastic polyimide layer 111 and the thermoplastic polyimide layer 112 constituting the polyimide layers 110 and 110 will be described. The "non-thermoplastic polyimide" is generally a polyimide that does not soften or show adhesiveness even when heated, but in the present invention, it was measured using a dynamic viscoelasticity measuring device (DMA). A polyimide having a storage elastic modulus of 1.0 × 10 ⁹ Pa or more at ° C. and a storage elastic modulus of 1.0 × 10 ⁸ Pa or more at 350 ° C. Further, the "thermoplastic polyimide" is generally a polyimide in which the glass transition temperature (Tg) can be clearly confirmed, but in the present invention, the storage elastic modulus at 30 ° C. measured using DMA is 1.0. A polyimide having a storage elastic modulus of × 10 ⁹ Pa or more and a storage elastic modulus of ^{less than 1.0 × 10 8 Pa at 350 ° C.}

Non-thermoplastic polyimide layer:
The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 contains a tetracarboxylic acid residue and a diamine residue. The non-thermoplastic polyimide preferably contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic acid dianhydride and an aromatic diamine residue derived from an aromatic diamine.

(Tetracarboxylic acid residue)
The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 has 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA) and 1,4-phenylenebis (BPDA) as tetracarboxylic acid residues. Tetracarboxylic acid residue derived from at least one of trimellitic acid monoester) dianhydride (TAHQ) and pyromellitic acid dianhydride (PMDA) and 2,3,6,7-naphthalenetetracarboxylic acid dianhydride It preferably contains a tetracarboxylic acid residue derived from at least one of the substances (NTCDA).

The tetracarboxylic acid residue derived from BPDA (hereinafter, also referred to as “BPDA residue”) and the tetracarboxylic acid residue derived from TAHQ (hereinafter, also referred to as “TAHQ residue”) are in the order of the polymer. It is easy to form a structure, and the dielectric positivity and hygroscopicity can be reduced by suppressing the movement of molecules. The BPDA residue can impart the self-supporting property of the gel film as the polyamic acid of the polyimide precursor, but on the other hand, it increases the CTE after imidization and lowers the glass transition temperature to lower the heat resistance. It becomes a tendency.

From this point of view, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 preferably contains 30 mol parts of the total of BPDA residues and TAHQ residues with respect to 100 mol parts of all tetracarboxylic acid residues. The content is controlled to be contained in the range of 60 mol parts or more, more preferably 40 mol parts or more and 50 mol parts or less. If the total of BPDA residues and TAHQ residues is less than 30 mol parts, the formation of the ordered structure of the polymer is insufficient, the moisture absorption resistance is lowered, and the reduction of dielectric loss tangent is insufficient, and 60 mol parts is used. If it exceeds the limit, the CTE may increase, the amount of change in the in-plane retardation (RO) may increase, and the heat resistance may decrease.

Further, a tetracarboxylic acid residue derived from pyromellitic dianhydride (hereinafter, also referred to as “PMDA residue”) and a tetra derived from 2,3,6,7-naphthalenetetracarboxylic dianhydride. Since the carboxylic acid residue (hereinafter, also referred to as "NTCDA residue") has rigidity, it enhances in-plane orientation, suppresses CTE to a low level, controls in-plane retardation (RO), and controls the glass transition temperature. It is a residue that plays a role in controlling. On the other hand, since PMDA residues have a small molecular weight, if the amount is too large, the imide group concentration of the polymer will increase, the polar groups will increase, and the hygroscopicity will increase, and the water content inside the molecular chain will increase. The dielectric positive contact increases due to the influence. In addition, the NTCDA residue tends to make the film brittle due to the highly rigid naphthalene skeleton, and tends to increase the elastic modulus.
Therefore, in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer, the total of PMDA residues and NTCDA residues is preferably 40 mol parts or more and 70 mol parts or less with respect to 100 mol parts of all tetracarboxylic acid residues. It is contained in the range of 50 mol parts or more and 60 mol parts or less, more preferably 50 to 55 mol parts or less. If the total of PMDA residues and NTCDA residues is less than 40 mol parts, CTE may increase or heat resistance may decrease, and if it exceeds 70 mol parts, the imide group concentration of the polymer becomes high and the polarity There is a risk that the number of groups will increase and the low moisture absorption property will be impaired, the dielectric positive contact will increase, and the film will become brittle and the self-supporting property of the film will decrease.

Further, the total of at least one BPDA residue and TAHQ residue and at least one PMDA residue and NTCDA residue is 80 mol parts or more, preferably 90 parts or more, based on 100 mol parts of all tetracarboxylic acid residues. It is preferably a molar portion or more.

Further, the molar ratio of at least one BPDA residue and TAHQ residue to at least one PMDA residue and NTCDA residue {(BPDA residue + TAHQ residue) / (PMDA residue + NTCDA residue)} is 0. The formation of the ordered structure of CTE and polymer is controlled by setting it in the range of 4 or more and 1.5 or less, preferably in the range of 0.6 or more and 1.3 or less, more preferably in the range of 0.8 or more and 1.2 or less. It is good to do.

Since PMDA and NTCDA have a rigid skeleton, it is possible to control the in-plane orientation of molecules in polyimide as compared with other general acid anhydride components, and suppress the coefficient of thermal expansion (CTE) and glass. It has the effect of improving the transition temperature (Tg). Further, since BPDA and TAHQ have a larger molecular weight than PMDA, the imide group concentration decreases as the charging ratio increases, which is effective in reducing the dielectric loss tangent and the hygroscopicity. On the other hand, when the charging ratio of BPDA and TAHQ increases, the in-plane orientation of the molecules in the polyimide decreases, which leads to an increase in CTE. Furthermore, the formation of an ordered structure in the molecule progresses, and the haze value increases. From this point of view, the total amount of PMDA and NTCDA charged is in the range of 40 to 70 mol parts, preferably in the range of 50 to 60 mol parts, with respect to 100 mol parts of the total acid anhydride component of the raw material. More preferably, it is in the range of 50 to 55 mol parts. If the total amount of PMDA and NTCDA charged is less than 40 mol parts with respect to 100 mol parts of the total acid anhydride component of the raw material, the in-plane orientation of the molecule is lowered, it becomes difficult to reduce the CTE, and Tg. The heat resistance and dimensional stability of the film during heating are reduced due to the decrease in heat resistance. On the other hand, when the total amount of PMDA and NTCDA charged exceeds 70 mol parts, the hygroscopicity tends to deteriorate or the elastic modulus tends to increase due to the increase in the imide group concentration.

Further, BPDA and TAHQ are effective in suppressing molecular motion, lowering the dielectric loss tangent by lowering the imide group concentration, and lowering the moisture absorption rate, but increase the CTE as a polyimide film after imidization. From this point of view, the total amount of BPDA and TAHQ charged is in the range of 30 to 60 mol parts, preferably in the range of 40 to 50 mol parts, with respect to 100 mol parts of the total acid anhydride component of the raw material. More preferably, it is in the range of 40 to 45 mol parts.

Examples of the tetracarboxylic acid residue other than the BPDA residue, TAHQ residue, PMDA residue, and NTCDA residue contained in the non-thermal polyimide constituting the non-thermal polyimide layer 111 include 3,3',. 4,4'-Diphenylsulfone tetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3,3 '-, 2,3,3', 4'-or 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 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) sulfonate dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethanedi Anhydride 1,2,7,8-,1,2,6,7-or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride 2,3,6,7-anthracene tetracarboxylic acid Dianhydride 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride 2,3,5,6-cyclohexane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid Dianhydride 1,4,5,8-Naphthalenetetracarboxylic dianhydride 4,8-Dimethyl-1,2,3,5,6,7-Hexahydronaphthalene-1,2,5,6- Tetracarboxylic acid dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid 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 acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride, 4,4' -Bis (2,3 -Dicarboxyphenoxy) Examples thereof include tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydrides such as diphenylmethane dianhydride and ethylene glycol bisamhydrotrimeritate.

(Diamine residue)
As the diamine residue contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111, a diamine residue derived from the diamine compound represented by the general formula (A1) is preferable.

In the formula (A1), the linking group Z represents a single bond or −COO−, and Y is a monovalent hydrocarbon having 1 to 3 carbon atoms which may be independently substituted with a halogen atom or a phenyl group, or a carbon number of carbon atoms. It represents an alkoxy group of 1 to 3 or a perfluoroalkyl group or an alkenyl group having 1 to 3 carbon atoms, n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4. Here, "independently" means that, in the above formula (A1), a plurality of substituents Y and further integers p and q may be the same or different. In the above formula (A1), the hydrogen atom in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ are independently alkyl groups and the like. It may mean any substituent).

The diamine compound represented by the general formula (A1) (hereinafter, may be referred to as “diamine (A1)”) is an aromatic diamine having 1 to 3 benzene rings. Since the diamine (A1) has a rigid structure, it has an action of imparting an ordered structure to the entire polymer. Therefore, a polyimide having low gas permeability and low hygroscopicity can be obtained, and the water content inside the molecular chain can be reduced, so that the dielectric loss tangent can be lowered. Here, as the linking group Z, a single bond is preferable.

Examples of the diamine (A1) include 1,4-diaminobenzene (p-PDA; para-phenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-. Examples thereof include n-propyl-4,4'-diaminobiphenyl (m-NPB) and 4-aminophenyl-4'-aminobenzoate (APAB).

The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 contains a diamine residue derived from diamine (A1) in an amount of preferably 80 mol parts or more, more preferably 80 mol parts or more, based on 100 mol parts of all diamine residues. It is preferable to contain 85 mol parts or more. By using the diamine (A1) in an amount within the above range, the rigid structure derived from the monomer facilitates the formation of an ordered structure throughout the polymer, resulting in low gas permeability, low hygroscopicity, and low dielectric loss tangent. Non-thermoplastic polyimide can be easily obtained.

Further, when the diamine residue derived from diamine (A1) is in the range of 80 mol parts or more and 85 mol parts or less with respect to 100 mol parts of all diamine residues in the non-thermoplastic polyimide, it is more rigid. It is preferable to use 1,4-diaminobenzene as the diamine (A1) from the viewpoint of the structure having excellent in-plane orientation.

Examples of other diamine residues contained in the non-thermal polyimide constituting the non-thermal polyimide layer 111 include 2,2-bis- [4- (3-aminophenoxy) phenyl] propane and 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-xylylene Amin, p-xylylene diamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazin, 2'-methoxy-4,4'- Diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, etc. Is it an aromatic diamine compound? Diamine residue derived from diamine residue, diamine residue derived from an aliphatic diamine compound such as diamine derived from dimer acid in which the two terminal carboxylic acid groups of dimer acid are replaced with a primary aminomethyl group or an amino group. Can be mentioned.

Thermal expansion in non-thermoplastic polyimide by selecting the types of the tetracarboxylic acid residue and diamine residue and the molar ratio of each when two or more types of tetracarboxylic acid residue or diamine residue are applied. The coefficient, storage elasticity, tensile elasticity, etc. can be controlled. Further, in the non-thermoplastic polyimide, when a plurality of structural units of polyimide are present, they may exist as blocks or randomly, but they are random from the viewpoint of suppressing variation in in-plane retardation (RO). It is preferable to be present in.

By using both the tetracarboxylic acid residue and the diamine residue contained in the non-thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide film in a high temperature environment is improved, and in-plane retardation (RO) is performed. It is preferable because the amount of change in is small.

The imide group concentration of the non-thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33%, the molecular weight of the resin itself becomes small, and the decrease in hygroscopicity deteriorates due to the increase in polar groups. By selecting the combination of the acid anhydride and the diamine compound, the orientation of the molecules in the non-thermoplastic polyimide is controlled, thereby suppressing the increase in CTE due to the decrease in the imide group concentration and ensuring low moisture absorption. ing.

The weight average molecular weight of the non-thermoplastic polyimide is preferably in the range of, for example, 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. If the weight average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased, and defects such as film thickness unevenness and streaks tend to occur during the coating operation.

The thickness of the non-thermoplastic polyimide layer 111 is preferably in the range of 6 μm or more and 100 μm or less, preferably 9 μm, from the viewpoint of ensuring the function as a base layer and transportability during manufacturing and coating with the thermoplastic polyimide. It is more preferably in the range of 50 μm or more. If the thickness of the non-thermoplastic polyimide layer 111 is less than the above lower limit value, the electrical insulation and handleability are insufficient, and if it exceeds the upper limit value, the productivity is lowered.

From the viewpoint of heat resistance, the non-thermoplastic polyimide layer 111 preferably has a glass transition temperature (Tg) of 280 ° C. or higher.

Further, from the viewpoint of suppressing warpage, the coefficient of thermal expansion of the non-thermoplastic polyimide layer 111 is in the range of 1 pm / K or more and 30 ppm / K or less, preferably in the range of 1 ppm / K or more and 25 ppm / K or less, more preferably. It is preferably in the range of 10 ppm / K or more and 20 ppm / K or less.

Further, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 includes, as optional components, other curing resin components such as a plasticizer and an epoxy resin, a curing agent, a curing accelerator, a coupling agent, a filler, and the like. A solvent, a flame retardant, etc. can be appropriately blended. However, some plasticizers contain a large amount of polar groups, which may promote the diffusion of copper from the copper wiring. Therefore, it is preferable not to use the plasticizer as much as possible.

Thermoplastic polyimide layer:
The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 contains a tetracarboxylic acid residue and a diamine residue, and the aromatic tetracarboxylic acid residue and the aromatic are derived from the aromatic tetracarboxylic acid dianhydride. It preferably contains an aromatic diamine residue derived from diamine.

(Tetracarboxylic acid residue)
The tetracarboxylic acid residue used in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is the same as that exemplified as the tetracarboxylic acid residue in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111. Can be used.

(Diamine residue)
The diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is a diamine residue derived from the diamine compounds represented by the general formulas (B1) to (B7) described for the adhesive polyimide described above. Is preferable.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 contains diamine residues derived from at least one diamine compound selected from diamines (B1) to diamines (B7) with respect to 100 mol parts of all diamine residues. It may be contained in a range of 60 mol parts or more, preferably 60 mol parts or more and 99 mol parts or less, and more preferably 70 mol parts or more and 95 mol parts or less. Since diamines (B1) to diamines (B7) have a flexible molecular structure, the flexibility of the polyimide molecular chain is improved by using at least one diamine compound selected from these in an amount within the above range. And can impart thermoplasticity. If the total amount of diamine (B1) to diamine (B7) in the raw material is less than 60 mol parts with respect to 100 mol parts of the total diamine component, sufficient thermoplasticity cannot be obtained due to insufficient flexibility of the polyimide resin.

Further, as the diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112, a diamine residue derived from the diamine compound represented by the general formula (A1) is also preferable. The diamine compound [diamine (A1)] represented by the formula (A1) is as described in the description of the non-thermoplastic polyimide. Since the diamine (A1) has a rigid structure and has an action of imparting an ordered structure to the entire polymer, it is possible to reduce dielectric loss tangent and hygroscopicity by suppressing the movement of molecules. Further, by using it as a raw material for thermoplastic polyimide, a polyimide having low gas permeability and excellent long-term heat-resistant adhesiveness can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 contains the diamine residue derived from the diamine (A1) in an amount of preferably 1 mol part or more and 40 mol parts or less, more preferably 5 mol parts or more and 30 mol parts or more. It may be contained within the following range. By using the diamine (A1) in an amount within the above range, an ordered structure is formed in the entire polymer due to the rigid structure derived from the monomer. A polyimide having excellent heat-resistant adhesiveness can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 can contain diamine residues derived from diamine compounds other than diamines (A1) and (B1) to (B7) as long as the effects of the invention are not impaired. ..

Thermal expansion coefficient by selecting the types of the tetracarboxylic acid residue and diamine residue and the molar ratio of each when two or more types of tetracarboxylic acid residue or diamine residue are applied to the thermoplastic polyimide. , Tensile elasticity, glass transition temperature, etc. can be controlled. Further, in the thermoplastic polyimide, when a plurality of structural units of polyimide are present, it may exist as a block or randomly, but it is preferable that it exists randomly.

By using both the tetracarboxylic acid residue and the diamine residue contained in the thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide film in a high temperature environment can be improved, and in-plane retardation (RO) can be used. The amount of change can be suppressed.

The imide group concentration of the thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33%, the molecular weight of the resin itself becomes small, and the decrease in hygroscopicity deteriorates due to the increase in polar groups. By controlling the orientation of the molecules in the thermoplastic polyimide by selecting the combination of the above diamine compounds, the increase in CTE accompanying the decrease in the imide group concentration is suppressed, and low hygroscopicity is ensured.

The weight average molecular weight of the thermoplastic polyimide is preferably in the range of 10,000 to 400,000, more preferably in the range of 50,000 to 350,000, for example. If the weight average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased, and defects such as film thickness unevenness and streaks tend to occur during the coating operation.

Since the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is, for example, an adhesive layer in the insulating resin layer of the circuit board, a completely imidized structure is most preferable in order to suppress the diffusion of copper. However, a part of the polyimide may be amic acid. ^{The imidization rate is 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 (commercially available: FT / IR620 manufactured by JASCO Corporation). It is calculated from the absorbance of C = O expansion and contraction derived from the imide group of ^{1780 cm -1} based on the benzene ring absorber of.

The thickness of the thermoplastic polyimide layer 112 is preferably in the range of 1 μm or more and 10 μm or less, and more preferably in the range of 1 μm or more and 5 μm or less, from the viewpoint of ensuring the adhesive function. If the thickness of the thermoplastic polyimide layer 112 is less than the above lower limit value, the adhesiveness becomes insufficient, and if it exceeds the upper limit value, the dimensional stability tends to deteriorate.

From the viewpoint of suppressing warpage, the thermoplastic polyimide layer 112 has a coefficient of thermal expansion of 30 ppm / K or more, preferably in the range of 30 ppm / K or more and 100 ppm / K or less, and more preferably 30 ppm / K or more and 80 ppm / K or less. It should be within range.

In addition to polyimide, the resin used for the thermoplastic polyimide layer 112 includes optional components such as plasticizers, other curing resin components such as epoxy resins, curing agents, curing accelerators, inorganic fillers, and coupling agents. A filler, a solvent, a flame retardant and the like can be appropriately blended. However, some plasticizers contain a large amount of polar groups, which may promote the diffusion of copper from the copper wiring. Therefore, it is preferable not to use the plasticizer as much as possible.

In the metal-clad laminate 100, the coefficient of thermal expansion of the two polyimide layers 110 and the adhesive layer 120 as a whole is preferably 10 ppm / K or more, preferably 10 ppm / K or more and 30 ppm in order to ensure dimensional stability after circuit processing. It is preferably in the range of / K or less, more preferably in the range of 15 ppm / K or more and 25 ppm / K.
In the metal-clad laminate 100, the total thickness T1 of the two polyimide layers 110 and the adhesive layer 120, the thickness T2 of the adhesive layer 120, and the ratio (T2 / T1) of the thickness T2 of the adhesive layer 120 to the total thickness T1. Is as described with reference to FIG.

(Synthesis of polyimide)
The polyimide constituting the polyimide layer 110 can be produced by reacting the acid anhydride and diamine in a solvent to produce a precursor resin and then heating and closing the ring. The method for synthesizing the polyimide can be carried out according to the method described for the adhesive polyimide.

[Circuit board]
The metal-clad laminate 100 is mainly useful as a circuit board material for FPCs, rigid flex circuit boards, and the like. That is, a circuit board such as an FPC, which is an embodiment of the present invention, is formed by processing one or both of the two metal layers 101 of the metal-clad laminate 100 into a pattern by a conventional method to form a wiring layer. Can be manufactured. Although not shown, this circuit board is a resin laminate in which a first insulating resin layer (P1), an adhesive layer (A'), and a second insulating resin layer (P2) are laminated in this order. , A wiring layer provided on one side or both side surfaces of this resin laminate.

Examples will be shown below, and the features of the present invention will be described in more detail. However, the scope of the present invention is not limited to the examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of viscosity]
The viscosity was measured using an E-type viscometer (manufactured by Brookfield, trade name; DV-II + Pro) at 25 ° C. The rotation speed was set so that the torque was 10% to 90%, and 2 minutes after the start of the measurement, the value when the viscosity became stable was read.

[Measurement of storage elastic modulus and glass transition temperature (Tg)]
A resin sheet having a size of 5 mm × 20 mm was heated from 30 ° C. to 400 ° C. at a heating rate of 4 ° C./min using a dynamic viscoelasticity measuring device (DMA: manufactured by UBM Co., Ltd., trade name; E4000F). The measurement was performed at a frequency of 11 Hz. In addition, the temperature at which the value of the elastic modulus change (Tanδ) during measurement is maximized is defined as Tg.

[Measurement of relative permittivity and dielectric loss tangent]
The relative permittivity and dielectric loss tangent of the resin sheet at 10 GHz were measured using a vector network analyzer (manufactured by Agilent, trade name; E8633C) and an SPDR resonator. The material used for the measurement was left for 24 hours under the conditions of temperature; 24 to 26 ° C. and humidity of 45 ° C. to 55% RH.

[Measurement of coefficient of thermal expansion (CTE)]
A polyimide film having a size of 3 mm × 20 mm was heated from 30 ° C. to 265 ° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Bruker, trade name; 4000SA). Further, after holding at that temperature for 10 minutes, the mixture was cooled at a rate of 5 ° C./min, and the average coefficient of thermal expansion (coefficient of thermal expansion) in the longitudinal direction (MD) from 250 ° C. to 100 ° C. was determined.

[Measurement of dimensional change rate]
A metal-clad laminate having a size of 80 mm × 80 mm was prepared. After providing a dry film resist on the metal layer of this laminated plate, it is exposed and developed, and as shown in FIG. 4, 5 points are formed at intervals of 50 mm in the vertical direction (MD) and the horizontal direction (TD), respectively. Sixteen resist patterns having a diameter of 1 mm were formed so as to be measurable, and a position measurement target was prepared.
After measuring the distance between the targets of the resist pattern in the position measurement target in an atmosphere of temperature; 23 ± 2 ° C. and relative humidity: 50 ± 5%, the exposed portion of the metal layer of the resist pattern opening is etched. It was removed by (etching liquid temperature; 40 ° C. or lower, etching time; within 10 minutes), and as shown in FIG. 5, an evaluation sample having 16 metal layer residual points was prepared. This evaluation sample was allowed to stand in an atmosphere of temperature; 23 ± 2 ° C. and relative humidity: 50 ± 5% for 24 ± 4 hours, and then the distance between the residual points of the metal layer was measured. The dimensional change rate for each of the five normal conditions in the vertical direction and the horizontal direction is calculated, and the average value of each is used as the dimensional change rate after etching.
Next, the evaluation sample was heat-treated in an oven at 120 ° C. for 1 hour, and the distance between the remaining metal layer points was measured thereafter. The dimensional change rate after heating at each of the five locations in the vertical direction and the horizontal direction is calculated, and the average value of each is used as the dimensional change rate after heating.
Each dimensional change rate was calculated by the following formula.
Dimensional change rate after etching (%) = (BA) / A x 100
A; Distance between targets after resist development B; Distance between remaining metal layer points after metal layer etching Dimensional change rate after heating (%) = (CB) / B x 100
B; Distance between metal layer residual points after metal layer etching C; Distance between metal layer residual points after heating

[Measurement of surface roughness of copper foil]
Measurement of 10-point average roughness (Rz) Measurement of Force; 100 μN, Speed; 20 μm, Range; 800 μm using a stylus type surface roughness meter (manufactured by Kosaka Laboratory Co., Ltd., trade name: Surfcoder ET-3000) Obtained according to the conditions. The surface roughness was calculated by a method based on JIS-B0601: 1994.

The abbreviations used in the synthesis examples indicate the following compounds.
BTDA: 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride PMDA: pyromellitic acid dianhydride BPDA: 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride DAPE: 4, 4'-Diaminodiphenyl ether m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-bis (4-aminophenoxy) benzene DDA: aliphatic diamine with 36 carbon atoms (Croder) Made by Japan Co., Ltd., trade name: PRIAMINE1074, amine value: 205 mgKOH / g, mixture of cyclic and chain diamine diamines, content of dimer components; 95% by weight or more)
OP935: Aluminum phosphinic acid salt (manufactured by Clariant Japan, trade name; Exolit OP935)
N-12: Dodecanedioic acid dihydrazide DMAc: N, N-dimethylacetamide NMP: N-methyl-2-pyrrolidone

(Synthesis Example 1)
312 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 14.67 g of DAPE (0.073 mol) was dissolved in this reaction vessel with stirring in the vessel. Next, 23.13 g of BTDA (0.072 mol) was added. Then, stirring was continued for 3 hours to prepare a resin solution a of polyamic acid having a solution viscosity of 2,960 mPa · s.

(Synthesis Example 2)
200 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 1.335 g of m-TB (0.0063 mol) and 10.414 g of TPE-R (0.0356 mol) were dissolved in this reaction vessel with stirring in the vessel. Next, 0.932 g of PMDA (0.0043 mol) and 11.319 g of BPDA (0.0385 mol) were added. Then, stirring was continued for 2 hours to prepare a resin solution b of polyamic acid having a solution viscosity of 1,420 mPa · s.

(Synthesis Example 3)
250 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 12.323 g of m-TB (0.0580 mol) and 1.886 g of TPE-R (0.0064 mol) were dissolved in this reaction vessel with stirring in the vessel. Next, 8.314 g of PMDA (0.0381 mol) and 7.477 g of BPDA (0.0254 mol) were added. Then, stirring was continued for 3 hours to prepare a resin solution c of polyamic acid having a solution viscosity of 31,500 mPa · s.

(Synthesis Example 4)
44.92 g of BTDA (0.139 mol), 75.08 g of DDA (0.141 mol), in a 500 mL 4-neck flask with a nitrogen inlet tube, stirrer, thermocouple, Dean-Stark trap, and condenser. 168 g of NMP and 112 g of xylene were charged and mixed at 40 ° C. for 30 minutes to prepare a polyamic acid solution. The temperature of this polyamic acid solution was raised to 190 ° C., and the mixture was heated and stirred for 4 hours to remove distilled water and xylene from the system. Then, the mixture was cooled to 100 ° C., 112 g of xylene was added and stirred, and further cooled to 30 ° C. to complete imidization to obtain a polyimide resin solution d (solid content; 29.5% by weight).

(Production Example 1)
<Preparation of polyimide film 1>
Add 1.8 g of N-12 (0.0036 mol) and 12.5 g of OP935 to 169.49 g (50 g of solid content) of the resin solution d, and add 6.485 g of NMP and 19.345 g of xylene. Diluted to prepare polyimide varnish 1.

After drying, the polyimide varnish 1 is applied to the silicone-treated surface of the release base material so that the thickness becomes about 25 μm, dried by heating at 80 ° C., and peeled off from the release base material to prepare the polyimide film 1. bottom. The Tg of the polyimide film 1 was 53 ° C., the storage elastic modulus at 50 ° C. was 800 MPa, and the maximum value of the storage elastic modulus at 180 ° C. to 260 ° C. was 10 MPa.

(Production Example 2)
<Preparation of polyimide film 2>
The surface of one side of the electrolytic copper foil 1 (thickness 12 μm, Rz; 2.1 μm) is coated with a polyamic acid resin solution b so that the cured thickness is about 25 μm, and then heated and dried at 120 ° C. The solvent was removed. Further, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete imidization. The copper foil was etched and removed using an aqueous ferric chloride solution to prepare a polyimide film 2. The Tg of the polyimide film 2 was 250 ° C., the storage elastic modulus at 50 ° C. was 5000 MPa, and the maximum value of the storage elastic modulus at 180 ° C. to 260 ° C. was 3600 MPa.

(Production Example 3)
<Preparation of resin film 1>
The polyimide varnish 1 is coated on the surface of LCP film 1 (50 μm thickness, CTE; 29 ppm / ° C., manufactured by Kuraray Co., Ltd., trade name; Vecstar) so that the thickness after drying is about 5 μm, and then at 80 ° C. Heat dried. Next, the surface on the opposite side of the LCP film 1 was also coated with the polyimide varnish 1 so that the thickness after drying was about 5 μm, and then heat-dried at 80 ° C. to prepare a resin film 1. The relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin film 1 were 2.9 and 0.0021, respectively.

(Production Example 4)
<Preparation of resin film 2>

The resin solution b was applied to the surface of the LCP film 1 so that the thickness after curing was about 5 μm, and then heat-dried at 120 ° C. Next, the surface of the LCP film 1 on the opposite side was also coated with the resin solution b so that the thickness after curing was about 5 μm, and then heat-dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed from 120 ° C. to 260 ° C. to complete imidization, and the resin film 2 was prepared. The relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin film 2 were 3.1 and 0.0021, respectively.

(Production Example 5)
<Preparation of resin film 3>
A resin film 3 was prepared in the same manner as in Production Example 3 except that the thickness of the polyimide varnish 1 after drying was about 12.5 μm. The relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin film 3 were 2.8 and 0.0021, respectively.

(Production Example 6)
<Preparation of resin film 4>
A resin film 4 was prepared in the same manner as in Production Example 3 except that the thickness of the polyimide varnish 1 after drying was about 25 μm. The relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin film 4 were 2.8 and 0.0022, respectively.

(Production Example 7)
<Manufacturing of single-sided metal-clad laminate 1>
The resin solution b was uniformly applied to the surface of one side of the electrolytic copper foil 1 so that the thickness after curing was about 2 μm, and then heat-dried at 120 ° C. to remove the solvent. Next, the resin solution c was uniformly applied onto the resin solution c so as to have a thickness of about 21 μm after curing, and then heat-dried at 90 to 120 ° C. to remove the solvent. Further, the resin solution a was uniformly applied thereto so as to have a thickness of about 2 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed at 120 ° C. to 360 ° C. to complete imidization, and a single-sided metal-clad laminate 1 was produced. The CTE of the polyimide film 3 prepared by etching and removing the copper foil layer of the single-sided metal-clad laminate 1 with an aqueous ferric chloride solution was 23 ppm / ° C.

(Production Example 8)
<Manufacturing of single-sided metal-clad laminate 2>
The resin solution b was uniformly applied to the surface of one side of the electrolytic copper foil 1 so that the thickness after curing was about 2 μm, and then heat-dried at 120 ° C. to remove the solvent. Next, the resin solution c was uniformly applied onto the resin solution c so as to have a thickness of about 21 μm after curing, and then heat-dried at 90 to 120 ° C. to remove the solvent. Further, the resin solution b was uniformly applied onto the resin solution b so as to have a thickness of about 2 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed at 120 ° C. to 360 ° C. to complete imidization, and a single-sided metal-clad laminate 2 was produced. The CTE of the polyimide film 4 prepared by etching and removing the copper foil layer of the single-sided metal-clad laminate 2 with an aqueous ferric chloride solution was 22 ppm / ° C.

(Production Example 9)
<Manufacturing of single-sided metal-clad laminate 3>
After laminating the electrolytic copper foil 1 on the resin surface side of the single-sided metal-clad laminate 2, the double-sided metal-clad laminate 1 was produced by thermocompression bonding at 320 ° C. and 7 MPa for 30 minutes. The copper foil layer on one side of the double-sided copper-clad laminate 1 was removed by etching with an aqueous ferric chloride solution to prepare a single-sided metal-clad laminate 3 in which the roughened shape of the copper foil was transferred to the resin surface. .. The CTE of the polyimide film 5 prepared by etching and removing the copper foil layer of the single-sided metal-clad laminate 3 with an aqueous ferric chloride solution was 22 ppm / ° C.

[Example 1]
Two single-sided metal-clad laminates 1 and one resin film 1 are prepared and laminated in the order of single-sided metal-clad laminate 1 / resin film 1 / single-sided metal-clad laminate 1 and then at 180 ° C. and 3.5 MPa. Under the conditions, the double-sided metal-clad laminate 2 was prepared by heat-pressing for 60 minutes. The evaluation results of the double-sided metal-clad laminate 2 are as follows.
Dimensional change rate after etching in the MD direction; -0.04%
Dimensional change rate after etching in the TD direction; -0.03%
Dimensional change rate after heating in MD direction; + 0.02%
Dimensional change rate after heating in the TD direction; + 0.01%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 1 (thickness; 110 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 2 are 3.1, respectively. It was 0.0031.

[Example 2]
Two single-sided metal-clad laminates 2 and one resin film 1 are prepared and laminated in the order of single-sided metal-clad laminate 2 / resin film 1 / single-sided metal-clad laminate 2, and then at 180 ° C. and 3.5 MPa. Under the conditions, the double-sided metal-clad laminate 3 was prepared by heat-pressing for 60 minutes. The evaluation results of the double-sided metal-clad laminate 3 are as follows.
Dimensional change rate after etching in the MD direction; -0.05%
Dimensional change rate after etching in the TD direction; -0.03%
Dimensional change rate after heating in MD direction; -0.03%
Dimensional change rate after heating in the TD direction; ± 0.00%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 2 (thickness; 110 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 3 are 3.1, respectively. It was 0.0026.

[Comparative Example 1]
Two single-sided metal-clad laminates 1 and one resin film 2 are prepared, laminated in the order of single-sided metal-clad laminate 1 / resin film 2 / single-sided metal-clad laminate 1, and then at 320 ° C. and 7 MPa. , The double-sided metal-clad laminate 4 was prepared by heat-pressing for 30 minutes. The evaluation results of the double-sided metal-clad laminate 4 are as follows.
Dimensional change rate after etching in the MD direction; -0.03%
Dimensional change rate after etching in the TD direction; -0.01%
Dimensional change rate after heating in MD direction; -0.11%
Dimensional change rate after heating in the TD direction; -0.10%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 3 (thickness; 110 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 4 are 3.2, respectively. It was 0.0031.

[Example 3]
Two single-sided metal-clad laminates 2 and one resin film 3 are prepared and laminated in the order of single-sided metal-clad laminate 2 / resin film 3 / single-sided metal-clad laminate 2, and then at 180 ° C. and 3.5 MPa. Under the conditions, the double-sided metal-clad laminate 5 was prepared by heat-pressing for 60 minutes. The evaluation results of the double-sided metal-clad laminate 5 are as follows.
Dimensional change rate after etching in the MD direction; -0.06%
Dimensional change rate after etching in the TD direction; -0.05%
Dimensional change rate after heating in MD direction; + 0.04%
Dimensional change rate after heating in the TD direction; + 0.02%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 4 (thickness; 125 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 5 are 3.0, respectively. It was 0.0026.

[Example 4]
Two single-sided metal-clad laminates 2 and one resin film 4 are prepared and laminated in the order of single-sided metal-clad laminate 2 / resin film 4 / single-sided metal-clad laminate 2, and then at 180 ° C. and 3.5 MPa. Under the conditions, the double-sided metal-clad laminate 6 was prepared by heat-pressing for 60 minutes. The evaluation results of the double-sided metal-clad laminate 6 are as follows.
Dimensional change rate after etching in the MD direction; -0.05%
Dimensional change rate after etching in the TD direction; -0.04%
Dimensional change rate after heating in MD direction; + 0.01%
Dimensional change rate after heating in the TD direction; + 0.01%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 5 (thickness; 150 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 6 are 3.0, respectively. It was 0.0026.

[Comparative Example 2]
Two single-sided metal-clad laminates 2 and one LCP film 1 are prepared and laminated in the order of single-sided metal-clad laminate 2 / LCP film 1 / single-sided metal-clad laminate 2, and then at 305 ° C. and 7 MPa. Although thermocompression bonding was performed for 30 minutes, the adhesion between the resin surface of the single-sided metal-clad laminate 2 and the surface of the LCP film 1 was not sufficient, and a double-sided metal-clad laminate could not be obtained.

[Comparative Example 3]
Two single-sided metal-clad laminates 3 and one LCP film 1 are prepared, laminated in the order of single-sided metal-clad laminate 3 / LCP film 1 / single-sided metal-clad laminate 3, and then at 305 ° C. and 7 MPa. , The double-sided metal-clad laminate 7 was prepared by thermocompression bonding for 30 minutes. The evaluation results of the double-sided metal-clad laminate 7 are as follows.
Dimensional change rate after etching in the MD direction; -0.04%
Dimensional change rate after etching in the TD direction; -0.03%
Dimensional change rate after heating in MD direction; -0.12%
Dimensional change rate after heating in the TD direction; -0.12%
Further, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the resin laminate 6 (thickness; 100 μm) prepared by etching and removing the copper foil layers on both sides of the double-sided metal-clad laminate 7 are 3.2, respectively. It was 0.0027.

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

100 ... Metal-clad laminate, 101 ... Metal layer, 110 ... Polyimide layer, 111 ... Non-thermoplastic polyimide layer, 112 ... Thermoplastic polyimide layer, 120 ... Adhesive layer, 130 ... Single-sided metal-clad laminate

Claims (10)

Liquid crystal polymer layer and
A first adhesive layer laminated on one side of the liquid crystal polymer layer and
A second adhesive layer laminated on the opposite side of the liquid crystal polymer layer from the first adhesive layer,
It is a resin film with
The storage elastic modulus of the first adhesive layer and the second adhesive layer at 50 ° C. is independently 1800 MPa or less, and the maximum value of the storage elastic modulus at 180 to 260 ° C. is 800 MPa or less independently. A resin film characterized by this. The resin film according to claim 1, wherein the dielectric loss tangent of the entire resin film at 10 GHz is 0.005 or less. The resin film according to claim 1, wherein the first adhesive layer and the second adhesive layer each have a glass transition temperature (Tg) of 180 ° C. or lower. The first adhesive layer and the second adhesive layer contain polyimide as a resin component, and the first adhesive layer and the second adhesive layer contain polyimide as a resin component.
The polyimide contains an acid anhydride residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component, and two terminal carboxylic acid groups of dimer acid are added to all diamine residues. The resin film according to claim 1, wherein the resin film contains 50 mol% or more of a primary aminomethyl group or a diamine residue derived from a diamine derived from a dimer acid substituted with an amino group. The resin film according to claim 1, wherein the thickness of the liquid crystal polymer layer is TL, the thickness of the first adhesive layer is TB1, and the thickness of the second adhesive layer is TB2.
0.15 ≤ (TB1 + TB2) / (TL + TB1 + TB2) ≤ 0.70 A first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one surface of the first metal layer.
A second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one surface of the second metal layer.
An intermediate resin layer arranged so as to be in contact with the first insulating resin layer and the second insulating resin layer, and laminated between the first single-sided metal-clad laminate and the second single-sided metal-clad laminate. A metal-clad laminate with,
A metal-clad laminate characterized in that the intermediate resin layer is made of the resin film according to any one of claims 1 to 5. The total thickness T1 of the first insulating resin layer, the intermediate resin layer, and the second insulating resin layer is in the range of 50 to 500 μm, and the ratio of the thickness T2 of the intermediate resin layer to the total thickness T1 (T2). The metal-clad laminate according to claim 6, wherein / T1) is in the range of 0.50 to 0.90. Both the first insulating resin layer and the second insulating resin layer have a multilayer structure in which a thermoplastic polyimide layer, a non-thermoplastic polyimide layer, and a thermoplastic polyimide layer are laminated in this order.
The metal-clad laminate according to claim 6, wherein the intermediate resin layer is provided in contact with the two thermoplastic polyimide layers. The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains a tetracarboxylic acid residue and a diamine residue, and is a diamine represented by the following general formula (A1) with respect to 100 mol parts of all diamine residues. The metal-clad laminate according to claim 6, wherein the content of the diamine residue derived from the compound is 80 mol parts or more.

[In the formula (A1), the linking group Z represents a single bond or −COO−, and Y is a monovalent hydrocarbon or carbon having 1 to 3 carbon atoms which may be independently substituted with a halogen atom or a phenyl group. An alkoxy group having a number of 1 to 3 or a perfluoroalkyl group having a carbon number of 1 to 3 or an alkenyl group is indicated, n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4. ] A first circuit board having a first wiring layer and a first insulating resin layer laminated on at least one surface of the first wiring layer.
A second circuit board having a second wiring layer and a second insulating resin layer laminated on at least one surface of the second wiring layer.
A circuit board provided with an intermediate resin layer arranged so as to be in contact with the first insulating resin layer and the second insulating resin layer and laminated between the first circuit board and the second circuit board. And
A circuit board characterized in that the intermediate resin layer is made of the resin film according to any one of claims 1 to 5.

Images