CN110962410B

CN110962410B - Metal-clad laminate and circuit board

Info

Publication number: CN110962410B
Application number: CN201910885101.4A
Authority: CN
Inventors: 安藤智典; 西山哲平; 实森咏司
Original assignee: Nippon Steel and Sumikin Chemical Co Ltd
Current assignee: Nippon Steel Chemical and Materials Co Ltd
Priority date: 2018-09-28
Filing date: 2019-09-19
Publication date: 2023-09-05
Anticipated expiration: 2039-09-19
Also published as: CN110962410A; TWI814908B; JP7446741B2; JP2020055299A; CN117048152A; KR20200036770A; TW202012167A; CN117067718A; TW202346095A; CN110962410A9; JP2024059887A

Abstract

The invention provides a metal-clad laminate and a circuit board which can reduce transmission loss even in high-frequency transmission and have excellent dimensional stability. The metal-clad laminate includes: a first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one side 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 side of the second metal layer; and an adhesive layer disposed 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. The adhesive layer is made of thermoplastic resin or thermosetting resin, and has a storage elastic modulus of 1800MPa or less at 50 ℃; (ii) The maximum value of the storage elastic modulus in a temperature region of 180-260 ℃ is below 800 MPa; (iii) a glass transition temperature (Tg) of 180 ℃ or lower.

Description

Metal-clad laminate and circuit board

Technical Field

The present invention relates to a metal-clad laminate and a circuit board useful as electronic components.

Background

In recent years, along with the progress of miniaturization, weight saving, and space saving of electronic devices, there has been an increasing demand for flexible printed wiring boards (flexible printed circuits (Flexible Printed Circuits, FPC)) which are thin and lightweight, have flexibility, and have excellent durability even if repeatedly bent. Since the FPC can be mounted in a three-dimensional and high-density manner even in a limited space, its use is expanding in, for example, wiring of movable parts of electronic devices such as Hard Disk Drives (HDD), digital video discs (Digital Video Disc, DVD), smart phones, and parts such as cables and connectors.

In addition to the above-mentioned high density, the high performance of the device is advancing, and thus, a countermeasure against the high frequency of the transmission signal is also required. When a high-frequency signal is transmitted, if the transmission loss in the transmission path is large, there are disadvantages such as loss of the electric signal and a longer delay time of the signal. Therefore, in FPC in the future, reduction of transmission loss is also important. In order to cope with high-frequency signal transmission, an FPC using a liquid crystal polymer having a lower dielectric constant and a low dielectric loss tangent as a dielectric layer is used instead of polyimide which is generally used as an FPC material. However, although the liquid crystal polymer is excellent in dielectric characteristics, there is room for improvement in heat resistance and adhesion to a metal layer.

In addition, fluorine-based resins are also known as polymers having a low dielectric constant and a low dielectric loss tangent. For example, as an FPC material which can cope with high frequency signal transmission and is excellent in adhesion, an insulating film in which a polyimide adhesive film having a thermoplastic polyimide layer and a high heat resistance polyimide layer is laminated on both surfaces of a fluorine-based resin layer has been proposed (patent document 1). The insulating film of patent document 1 is excellent in dielectric characteristics because of using a fluorine-based resin, but has problems in dimensional stability, and particularly when applied to FPC, there is a concern that dimensional change before and after circuit processing due to etching becomes large. Therefore, it is difficult to increase the thickness of the fluorine-based resin and to increase the thickness ratio.

As a technique related to an adhesive layer used for an electronic material, there has been proposed the use of a resin composition containing an epoxy resin and a phenoxy resin or a resin composition containing a thermoplastic polyimide, a maleimide compound, or the like in an adhesive sheet (patent documents 2 and 3). The film-like adhesive sheets of patent document 2 and patent document 3 have the advantage of low glass transition temperature and high adhesion to a laminate. However, patent document 2 and patent document 3 do not investigate the possibility of application to high-frequency signal transmission or application to an adhesive layer of a metal-clad laminate.

[ Prior Art literature ]

[ patent literature ]

Patent document 1 Japanese patent laid-open publication No. 2017-24265

[ patent document 2] Japanese patent No. 6191800 publication

[ patent document 3] Japanese patent publication No. 5553108

Disclosure of Invention

[ problem to be solved by the invention ]

The purpose of the present invention is to provide a metal-clad laminate and a circuit board that can reduce transmission loss even during high-frequency transmission and that have excellent dimensional stability.

[ means for solving the problems ]

The present inventors have made diligent studies and as a result, have found that the above problems can be solved by using an adhesive layer having a low glass transition temperature and a low elastic modulus in a metal-clad laminate, and have completed the present invention.

The metal-clad laminate of the present invention is a metal-clad laminate comprising:

a first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one side 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 side of the second metal layer; and

and an adhesive layer disposed 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.

In the metal-clad laminate of the present invention, the adhesive layer is made of a thermoplastic resin or a thermosetting resin, and the following conditions (i) to (iii) are satisfied:

(i) The storage elastic modulus at 50 ℃ is below 1800 MPa;

(ii) The maximum value of the storage elastic modulus in a temperature region of 180-260 ℃ is below 800 MPa;

(iii) The glass transition temperature (Tg) is 180 ℃ or lower.

In the metal-clad laminate of the present invention, the total thickness T1 of the first insulating resin layer, the adhesive layer, and the second insulating resin layer may be in the range of 70 μm to 500 μm, and the ratio (T2/T1) of the thickness T2 of the adhesive layer to the total thickness T1 may be in the range of 0.5 to 0.8.

In the metal-clad laminate of the present invention, each of the first insulating resin layer and the second insulating resin layer may 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 adhesive layer may be disposed in contact with both of the thermoplastic polyimide layers.

In the metal-clad laminate of the present invention, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains tetracarboxylic acid residues and diamine residues, and the content of diamine residues derived from the diamine compound represented by the following general formula (1) may be 80 parts by mole or more based on 100 parts by mole of the total diamine residues.

[ chemical 1]

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

In the metal-clad laminate of the present invention, the thermal expansion coefficient of the first insulating resin layer, the adhesive layer, and the second insulating resin layer as a whole may be in the range of 10ppm/K to 30 ppm/K.

In the metal-clad laminate of the present invention, the first metal layer and the second metal layer may each include copper foil.

In the circuit board of the present invention, the first metal layer and/or the second metal layer of any one of the metal-clad laminate plates is processed into wiring.

[ Effect of the invention ]

The metal-clad laminate of the present invention has a structure in which two single-sided metal-clad laminates are bonded with an adhesive layer having specific parameters interposed therebetween, whereby the thickness of the insulating resin layer can be increased and dimensional stability can be ensured. In addition, when the invention is applied to a circuit board or the like for transmitting a high-frequency signal of 10GHz or more, transmission loss can be reduced. Therefore, the reliability and yield can be improved in the circuit board.

Drawings

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

Fig. 2 is a schematic cross-sectional view showing the structure of a metal-clad laminate according to a preferred embodiment of the present invention.

[ description of symbols ]

100: a metal clad laminate;

101: a metal layer;

110: a polyimide layer;

111: a non-thermoplastic polyimide layer;

112: a thermoplastic polyimide layer;

120: an adhesive polyimide layer;

130: a single-sided metal clad laminate;

b: an adhesive layer;

c: a metal clad laminate;

c1: a first single-sided metal-clad laminate;

c2: a second single-sided metal clad laminate;

m1: a first metal layer;

m2: a second metal layer;

p1: a first insulating resin layer;

p2: a second insulating resin layer;

t1: aggregate thickness;

t2, T3: thickness.

Detailed Description

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

[ Metal-clad laminate ]

Fig. 1 is a schematic view showing the structure 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 (B). That is, the metal-clad laminate (C) includes a first single-sided metal-clad laminate (C1), a second single-sided metal-clad laminate (C2), and an adhesive layer (B) laminated between the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2). The first single-sided metal-clad laminate (C1) has a first metal layer (M1) and a first insulating resin layer (P1) laminated on at least one side surface of the first metal layer (M1). The second single-sided metal-clad laminate (C2) has a second metal layer (M2), and a second insulating resin layer (P2) laminated on at least one side surface of the second metal layer (M2). The adhesive layer (B) is disposed so as to be in contact with the first insulating resin layer (P1) and the second insulating resin layer (P2). That is, the metal-clad laminate (C) has a structure in which a first metal layer (M1)/a first insulating resin layer (P1)/an adhesive layer (B)/a second insulating resin layer (P2)/a second metal layer (M2) are laminated in this order. The first metal layer (M1) and the second metal layer (M2) are located outermost, the first insulating resin layer (P1) and the second insulating resin layer (P2) are disposed inside the first metal layer and the second metal layer, and the adhesive layer (B) is disposed between the first insulating resin layer (P1) and the second insulating resin layer (P2).

< Single-sided Metal-clad laminate >)

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

(Metal layer)

The material of the first metal layer (M1) and the second metal layer (M2) is not particularly limited, and examples thereof include: copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, alloys thereof, and the like. Among them, copper or copper alloy is 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 thicknesses of the first metal layer (M1) and the second metal layer (M2) are not particularly limited, and for example, in the case of using a metal foil such as a copper foil, the thickness is preferably 35 μm or less, and more preferably in the range of 5 μm to 25 μm. The lower limit of the thickness of the metal foil is preferably set to 5 μm from the viewpoint of production stability and handling properties. In the case of using a copper foil, the copper foil may be a rolled copper foil or an electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

The metal foil may be subjected to surface treatment with, for example, a plate wall, an aluminum alkoxide, an aluminum chelate, a silane coupling agent, or the like for the purpose of, for example, rust prevention treatment or improvement of adhesion.

(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 made of a resin having electrical insulation properties, and examples thereof include: polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, tetrafluoroethylene (Ethyl Tetrafluoroethylene, ETFE), etc., but is preferably composed of polyimide. The first insulating resin layer (P1) and the second insulating resin layer (P2) are not limited to a single layer, and may be layers formed by stacking a plurality of resin layers. In the case of polyimide, in the present invention, the term "polyimide" means a resin containing a polymer having an imide group in a molecular structure such as polyamide imide, polyether imide, polyester imide, polysiloxane imide, polybenzimidazole imide, or the like, in addition to polyimide.

< adhesive layer >)

The adhesive layer (B) is composed of a thermoplastic resin or a thermosetting resin, and satisfies (i) a storage elastic modulus at 50 ℃ of 1800MPa or less, (ii) a maximum value of storage elastic modulus at 180-260 ℃ of 800MPa or less, and (iii) a glass transition temperature (Tg) of 180 ℃ or less. Examples of the resin include: polyimide resins, polyamide resins, epoxy resins, phenoxy resins, acrylic resins, polyurethane resins, styrene resins, polyester resins, phenol resins, polysulfone resins, polyethersulfone resins, polyphenylene sulfide resins, polyethylene resins, polypropylene resins, silicone resins, polyetherketone resins, polyvinyl alcohol resins, polyvinyl butyral resins, styrene-maleimide copolymers, maleimide-vinyl compound copolymers or (meth) acrylic acid copolymers, benzoxazine resins, bismaleimide resins, cyanate resins, and the like, among which materials satisfying the conditions (i) to (iii) or resins designed so as to satisfy the conditions (i) to (iii) may be selected for use in the adhesive layer (B).

When the adhesive layer (B) is a thermosetting resin, an organic peroxide, a curing agent, a curing accelerator, etc. may be contained, or a curing agent and a curing accelerator, or a catalyst and a cocatalyst may be used in combination as necessary. The amounts and the presence or absence of the addition of the curing agent, curing accelerator, catalyst, cocatalyst and organic peroxide may be determined within the range where the above conditions (i) to (iii) can be ensured.

< layer thickness >)

In the metal-clad laminate (C), when the total thickness of the first insulating resin layer (P1), the adhesive layer (B) and the second insulating resin layer (P2) is T1, the total thickness T1 is in the range of 70 [ mu ] m to 500 [ mu ] m, preferably in the range of 100 [ mu ] m to 300 [ mu ] m. If the total thickness T1 is less than 70 μm, the effect of reducing the transmission loss in the production of the circuit board is insufficient, and if it exceeds 500 μm, the productivity may be reduced.

The thickness T2 of the adhesive layer (B) is, for example, preferably 50 μm to 450 μm, and more preferably 50 μm to 250 μm. If the thickness T2 of the adhesive layer (B) does not satisfy the lower limit value, the transmission loss may increase as a high-frequency substrate. On the other hand, if the thickness of the adhesive layer (B) exceeds the upper limit value, there may be a problem such as a decrease in dimensional stability.

The ratio (T2/T1) of the thickness T2 of the adhesive layer (B) to the total thickness T1 is in the range of 0.5 to 0.8, preferably in the range of 0.5 to 0.7. If the ratio (T2/T1) is less than 0.5, it is difficult to set T1 to 70 μm or more, and if it exceeds 0.8, there occurs a problem such as a decrease in dimensional stability.

The thickness T3 of each of the first insulating resin layer (P1) and the second insulating resin layer (P2) is preferably in the range of, for example, 12 μm to 100 μm, and more preferably in the range of 12 μm to 50 μm. If the thickness T3 of the first insulating resin layer (P1) and the second insulating resin layer (P2) does not satisfy the lower limit value, there may be a problem such as warpage of the metal-clad laminate (C). If the thickness T3 of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds the upper limit value, defects such as reduced productivity and the like occur. Further, the first insulating resin layer (P1) and the second insulating resin layer (P2) may not necessarily have the same thickness.

< coefficient of thermal expansion >

The coefficient of thermal expansion (Coefficient of Thermal Expansion, CTE) of the first insulating resin layer (P1) and the second insulating resin layer (P2) may be in the range of 10ppm/K or more, preferably 10ppm/K or more and 30ppm/K or less, more preferably 15ppm/K or more and 25ppm/K or less. If the CTE is less than 10ppm/K or exceeds 30ppm/K, warpage or a decrease in dimensional stability occurs. By appropriately changing the combination of the raw materials used, the thickness, and the drying and curing conditions, a polyimide layer having a desired CTE can be produced.

The adhesive layer (B) has a low elasticity and a low glass transition temperature although having a high thermal expansion property, and therefore, even if the CTE exceeds 30ppm/K, the internal stress generated at the time of lamination can be relaxed.

The Coefficient of Thermal Expansion (CTE) of the entire first insulating resin layer (P1), adhesive layer (B) and second insulating resin layer (P2) may be 10ppm/K or more, preferably 10ppm/K or more and 30ppm/K or less, and more preferably 15ppm/K or more and 25ppm/K or less. If the CTE of the whole of these resin layers is less than 10ppm/K or more than 30ppm/K, warpage or a decrease in dimensional stability occurs.

< glass transition temperature (Tg) >)

The glass transition temperature (Tg) of the adhesive layer (B) is 180℃or lower, and may preferably be 160℃or lower. By setting the glass transition temperature of the adhesive layer (B) to 180 ℃ or lower, thermocompression bonding can be performed at a low temperature, and therefore internal stress generated during lamination can be relaxed, and dimensional change after circuit processing can be suppressed. If Tg of the adhesive layer (B) exceeds 180 ℃, temperature at the time of adhesion through the first insulating resin layer (P1) and the second insulating resin layer (P2) may be increased, and dimensional stability after circuit processing may be impaired.

< storage elastic modulus >)

The adhesive layer (B) has a storage elastic modulus at 50 ℃ of 1800MPa or less and a maximum value of storage elastic modulus at a temperature range of 180-260 ℃ of 800MPa or less. The property of the adhesive layer (B) is considered to be a factor of relaxing internal stress at the time of thermocompression bonding and maintaining dimensional stability after circuit processing. The storage elastic modulus of the adhesive layer (B) at the upper limit temperature (260 ℃) of the temperature range is preferably 800MPa or less, more preferably 500MPa or less. By setting the storage elastic modulus as described above, warpage is less likely to occur even after the reflow step after the circuit processing.

Dielectric loss tangent

When the first insulating resin layer (P1) and the second insulating resin layer (P2) are applied to a circuit board, for example, the dielectric loss tangent (Tan δ) at 10GHz may be preferably 0.02 or less, more preferably in the range of 0.0005 or more and 0.01 or less, and still more preferably in the range of 0.001 or more and 0.008 or less, in order to suppress deterioration of dielectric loss. If the dielectric loss factor at 10GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds 0.02, then when applied to a circuit board, defects such as loss of an electrical signal on a transmission path of a high-frequency signal are likely to occur. On the other hand, the lower limit value of the dielectric loss tangent at 10GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) is not particularly limited, but physical property control of the insulating resin layers as the circuit substrate is considered.

When the adhesive layer (B) is applied to a circuit board, for example, the dielectric loss tangent (Tan δ) at 10GHz may be preferably 0.015 or less, more preferably 0.01 or less, and still more preferably 0.006 or less in order to suppress deterioration of dielectric loss. If the dielectric loss tangent of the adhesive layer (B) at 10GHz exceeds 0.015, the dielectric loss factor tends to cause defects such as loss of an electrical signal on a transmission path of a high-frequency signal when applied to a circuit board. On the other hand, the lower limit value of the dielectric loss tangent at 10GHz of the adhesive layer (B) is not particularly limited.

Dielectric constant >, a method of manufacturing a semiconductor device

When the first insulating resin layer (P1) and the second insulating resin layer (P2) are used as insulating resin layers for circuit boards, for example, the dielectric constant at 10GHz is preferably 4.0 or less as the whole insulating resin layer in order to ensure impedance matching. If the dielectric constant at 10GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds 4.0, the dielectric loss of the first insulating resin layer (P1) and the second insulating resin layer (P2) is deteriorated when applied to a circuit board, and the electric signal loss on the transmission path of a high-frequency signal is liable to occur.

When the adhesive layer (B) is applied to a circuit board, for example, the dielectric constant at 10GHz is preferably 4.0 or less in order to ensure impedance matching. If the dielectric constant of the adhesive layer (B) at 10GHz exceeds 4.0, the dielectric loss of the adhesive layer (B) is deteriorated when applied to a circuit board, and there is a possibility that defects such as loss of an electrical signal on a transmission path of a high-frequency signal are generated.

< action >

In the metal-clad laminate (C) of the present embodiment, the thickness of the adhesive layer (B) itself is increased in order to achieve low dielectric loss factor of the entire insulating resin layer and to cope with high frequency transmission. However, in general, a material having a low elastic modulus as in the adhesive layer (B) exhibits a high thermal expansion coefficient, and thus an increase in the layer thickness may cause a decrease in dimensional stability. The dimensional change occurring when the metal-clad laminate (C) is subjected to circuit processing is considered to be mainly caused by the mechanisms of a) to C) described below, and the total amount of b) and C) is represented as the dimensional change after etching.

a) In the production of the metal-clad laminate (C), internal stress is accumulated in the resin layer.

b) During circuit processing, the internal stress accumulated in a) is released by etching the metal layer, and the resin layer expands or contracts.

c) During circuit processing, the exposed resin absorbs moisture and swells by etching the metal layer.

The main causes of the internal stress of a) are 1) the difference in thermal expansion coefficients between the metal layer and the resin layer, and 2) the internal strain of the resin due to filming. Here, the magnitude of the internal stress caused by 1) affects not only the difference in thermal expansion coefficient but also the temperature difference Δt from the temperature at the time of adhesion (heating temperature) to the temperature at which cooling solidifies. That is, since the internal stress increases in proportion to the temperature difference Δt, the adhesion requires a resin having a high temperature even if the difference in thermal expansion coefficient between the metal layer and the resin layer is small, and the internal stress increases. In the metal-clad laminate (C) of the present embodiment, the layer satisfying the above-described conditions (i) to (iii) is used as the adhesive layer (B), and the internal stress is reduced to ensure dimensional stability.

In addition, the adhesive layer (B) is laminated between the first insulating resin layer (P1) and the second insulating resin layer (P2), and thus functions as an intermediate layer, suppressing warpage and dimensional change. Further, in a heating step such as reflow (reflow) at the time of mounting a semiconductor chip, direct heat or contact with oxygen is blocked by the first insulating resin layer (P1) or the second insulating resin layer (P2), and thus, dimensional change is less likely to occur due to the influence of oxidative deterioration. In this way, there is also an advantage brought about by the characteristic of the layer constitution of the first insulating resin layer (P1), the adhesive layer (B) and the second insulating resin layer (P2).

[ production of Metal-clad laminate ]

The metal-clad laminate (C) can be produced by, for example, the following method 1 or method 2.

[ method 1]

And a method in which a resin composition to be an adhesive layer (B) is formed into a sheet shape to form an adhesive sheet, and the adhesive sheet is arranged and bonded between a first insulating resin layer (P1) of a first single-sided metal-clad laminate (C1) and a second insulating resin layer (P2) of a second single-sided metal-clad laminate (C2), and thermal compression bonding is performed.

[ method 2]

And a method in which a solution of a resin composition to be an adhesive layer (B) is applied to either or both of a first insulating resin layer (P1) of a first single-sided metal-clad laminate (C1) and a second insulating resin layer (P2) of a second single-sided metal-clad laminate (C2) at a predetermined thickness, and then dried, and then one side of the applied film is bonded to the film, followed by thermocompression bonding.

The adhesive sheet used in method 1 can be produced, for example, by a method of forming an adhesive sheet by applying a solution of the resin composition to be the adhesive layer (B) on an arbitrary support substrate, drying the solution, and then peeling the dried solution from the support substrate.

In the above description, the method of applying the solution of the resin composition to be the adhesive layer (B) to the support substrate or the insulating resin layers (P1, P2) is not particularly limited, and the application may be performed by, for example, an applicator such as a bevel wheel, a die, a doctor blade, or a die lip.

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

[ preferable construction example of Metal-clad laminate ]

Next, the first insulating resin layer (P1), the second insulating resin layer (P2), the adhesive layer (B), the first metal layer (M1), and the second metal layer (M2) in the metal-clad laminate (C) of the present embodiment will be described in more detail.

Fig. 2 is a schematic cross-sectional view showing the structure of the metal-clad laminate 100 according to the present embodiment. As shown in fig. 2, the metal-clad laminate 100 includes: metal layers 101, 101 as a first metal layer (M1) and a second metal layer (M2); polyimide layers 110, 110 as a first insulating resin layer (P1) and a second insulating resin layer (P2); and an adhesive polyimide layer 120 as an adhesive layer (B). Here, the metal layer 101 and the polyimide layer 110 form a single-sided metal clad laminate 130 as the first single-sided metal clad laminate (C1) or the second single-sided metal clad laminate (C2). In this embodiment, the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) have the same structure.

Each of the polyimide layers 110 and 110 may have a structure in which a plurality of polyimide layers are stacked. For example, in the embodiment shown in fig. 2, a three-layer structure including non-thermoplastic polyimide layers 111 and 111 made of non-thermoplastic polyimide as a base layer and thermoplastic polyimide layers 112 and 112 made of thermoplastic polyimide provided on both sides of the non-thermoplastic polyimide layers 111 and 111, respectively, is formed. Further, the polyimide layers 110, 110 are not limited to a three-layer structure, respectively.

In the metal-clad laminate 100 shown in fig. 2, the outer thermoplastic polyimide layers 112, 112 of the two single-sided metal-clad laminates 130, 130 are bonded to the adhesive polyimide layer 120, respectively, to form the metal-clad laminate 100. The adhesive polyimide layer 120 is an adhesive layer for bonding the two single-sided metal clad laminate plates 130, 130 to the metal clad laminate plate 100, and is a layer for thickening the insulating resin layer of the metal clad laminate plate 100 while securing dimensional stability. The adhesive polyimide layer 120 is as described for the adhesive layer (B).

Next, the non-thermoplastic polyimide layer 111 and the thermoplastic polyimide layer 112 constituting the polyimide layers 110 and 110 will be described. The term "non-thermoplastic polyimide" is usually polyimide which does not exhibit softening and tackiness even when heated, but in the present invention means a polyimide obtained by using a Dynamic viscoelasticity measuring apparatus (Dynamic mechanical analyzer) cal Analysis, DMA)) to a storage elastic modulus at 30℃of 1.0X10 ⁹ Storage elastic modulus at 350 ℃ of Pa or more of 1.0X10 ⁸ Polyimide of Pa or more. The term "thermoplastic polyimide" is usually a polyimide whose glass transition temperature (Tg) can be clearly confirmed, but in the present invention, it means that the storage elastic modulus at 30 ℃ measured using DMA is 1.0x10 ⁹ The storage elastic modulus at 350 ℃ of Pa or more is less than 1.0X10 ⁸ Polyimide of Pa.

Non-thermoplastic polyimide layer:

the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 contains a tetracarboxylic acid residue and a diamine residue. In the present invention, the tetracarboxylic acid residue means a tetravalent group derived from tetracarboxylic dianhydride, and the diamine residue means a divalent group derived from a diamine compound. The polyimide preferably contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic 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 preferably contains, as tetracarboxylic acid residues, tetracarboxylic acid residues derived from at least one of 3,3', 4' -biphenyltetracarboxylic dianhydride (3, 3', 4' -biphenyl tetracarboxylic dianhydride, BPDA) and 1,4-phenylene bis (trimellitic acid monoester) dianhydride (TAHQ), and tetracarboxylic acid residues derived from at least one of pyromellitic dianhydride (pyromellitic dianhydride, PMDA) and 2,3,6,7-naphthalene tetracarboxylic dianhydride (2, 3,6,7-naphthalene tetracarboxylic dianhydride, NTCDA).

Tetracarboxylic acid residues derived from BPDA (hereinafter also referred to as "BPDA residues") and tetracarboxylic acid residues derived from TAHQ (hereinafter also referred to as "TAHQ residues") tend to form ordered structures of polymers, and dielectric loss tangent and hygroscopicity can be reduced by suppressing the movement of molecules. The BPDA residue can impart self-supporting properties to a gel film of polyamic acid as a polyimide precursor, but on the other hand, tends to increase CTE after imidization, lower glass transition temperature, and lower heat resistance.

From the above viewpoint, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 is controlled so that the non-thermoplastic polyimide contains a BPDA residue and a TAHQ residue in a total of preferably 30 to 60 parts by mole, more preferably 40 to 50 parts by mole, based on 100 parts by mole of all the tetracarboxylic acid residues. If the total of the BPDA residues and the TAHQ residues is less than 30 parts by mol, the formation of the ordered structure of the polymer becomes insufficient, the moisture absorption resistance is lowered, or the reduction of the dielectric loss tangent becomes insufficient, and if it exceeds 60 parts by mol, there is a concern that the heat resistance is lowered in addition to the increase in CTE or the increase in the amount of change in-plane Retardation (RO).

Further, since tetracarboxylic acid residues derived from pyromellitic dianhydride (hereinafter, also referred to as "PMDA residues") and tetracarboxylic acid residues derived from 2,3,6, 7-naphthalene tetracarboxylic dianhydride (hereinafter, also referred to as "NTCDA residues") have rigidity, they are residues that have an effect of improving in-plane orientation, suppressing CTE at a low level, and contributing to control of in-plane Retardation (RO), or control of glass transition temperature. On the other hand, PMDA residues have a small molecular weight, and therefore if the amount thereof is too large, the imide group concentration of the polymer increases, the polar group increases, the hygroscopicity increases, and the dielectric loss tangent increases due to the influence of moisture in the molecular chain. In addition, NTCDA residues tend to cause membrane embrittlement due to the naphthalene skeleton having high rigidity and increase the elastic modulus.

Accordingly, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer preferably contains PMDA residues in a total of 40 to 70 parts by mole, more preferably 50 to 60 parts by mole, and still more preferably 50 to 55 parts by mole based on 100 parts by mole of all the tetracarboxylic acid residues. If the total of PMDA residues and NTCDA residues is less than 40 parts by mole, there is a concern that CTE increases or heat resistance decreases, and if it exceeds 70 parts by mole, there is a concern that the imide group concentration of the polymer increases, the polar group increases and low hygroscopicity is impaired, the dielectric loss tangent increases, or the film becomes brittle and self-supporting property of the film decreases.

The total of at least one of the BPDA residue and the TAHQ residue and at least one of the PMDA residue and the NTCDA residue may be 80 parts by mole or more, preferably 90 parts by mole or more, based on 100 parts by mole of all tetracarboxylic acid residues.

The molar ratio of at least one of the BPDA residue and the TAHQ residue to at least one of the PMDA residue+tahq residue)/(PMDA residue+ntcda residue) } may be set to be in the range of 0.4 to 1.5, preferably in the range of 0.6 to 1.3, more preferably in the range of 0.8 to 1.2.

Since PMDA and NTCDA have rigid backbones, they can control the in-plane orientation of molecules in polyimide as compared with other general acid anhydride components, and have the effect of suppressing the Coefficient of Thermal Expansion (CTE) and increasing the glass transition temperature (Tg). Further, since BPDA and TAHQ have a larger molecular weight than PMDA, an increase in the loading ratio lowers the imide group concentration, which has an effect on a decrease in dielectric loss tangent and a decrease in moisture absorption rate. On the other hand, when the loading ratio of BPDA and TAHQ increases, the in-plane orientation of molecules in polyimide decreases, resulting in an increase in CTE. Further, the formation of an ordered structure within the molecule is advanced, and the haze value increases. From the above viewpoint, the total amount of PMDA and NTCDA to be added may be in the range of 40 to 70 parts by mol, preferably in the range of 50 to 60 parts by mol, and more preferably in the range of 50 to 55 parts by mol, based on 100 parts by mol of all acid anhydride components of the raw materials. If the total amount of PMDA and NTCDA to be incorporated is less than 40 parts by mole per 100 parts by mole of all acid anhydride components of the raw material, the in-plane orientation of the molecules is lowered, the CTE is difficult to lower, and the heat resistance and dimensional stability of the film upon heating due to the lowering of Tg are lowered. On the other hand, if the total amount of PMDA and NTCDA to be incorporated exceeds 70 parts by mole, the moisture absorption rate tends to be low or the elastic modulus tends to be high due to an increase in the imide group concentration.

Further, BPDA and TAHQ have effects of lowering the dielectric loss factor and lowering the moisture absorption rate due to the suppression of molecular movement and the lowering of the imide group concentration, but increase CTE as a polyimide film after imidization. From the above viewpoint, the total amount of the BPDA and TAHQ to be added may be in the range of 30 to 60 parts by mol, preferably in the range of 40 to 50 parts by mol, and more preferably in the range of 40 to 45 parts by mol, based on 100 parts by mol of all acid anhydride components of the raw material.

Examples of the tetracarboxylic acid residues other than the BPDA residue, TAHQ residue, PMDA residue, and NTCDA residue contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 include 3,3',4' -diphenyl sulfone tetracarboxylic dianhydride, 4' -oxydiphthalic anhydride, 2,3',3,4' -biphenyl tetracarboxylic dianhydride, 2',3,3' -benzophenone tetracarboxylic dianhydride, 2,3', 4' -benzophenone tetracarboxylic dianhydride or 3,3',4' -benzophenone tetracarboxylic dianhydride, 2,3',3,4' -diphenyl ether tetracarboxylic dianhydride, bis (2, 3-dicarboxyphenyl) ether dianhydride, 3',4' -p-terphenyl tetracarboxylic dianhydride, 2,3', 4' -p-terphenyl tetracarboxylic dianhydride or 2,2',3,3' -p-terphenyltetracarboxylic dianhydride, 2-bis (2, 3-dicarboxyphenyl) -propane dianhydride or 2, 2-bis (3, 4-dicarboxyphenyl) -propane dianhydride, bis (2, 3-dicarboxyphenyl) -methane dianhydride or bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) sulfone dianhydride or bis (3, 4-dicarboxyphenyl) sulfone dianhydride, 1-bis (2, 3-dicarboxyphenyl) ethane dianhydride or 1, 1-bis (3, 4-dicarboxyphenyl) ethane dianhydride, 1,2,7, 8-phenanthrene-tetracarboxylic dianhydride, 1,2,6, 7-phenanthrene-tetracarboxylic dianhydride or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6, 7-anthracene-tetracarboxylic dianhydride, 2-bis (3, 4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5, 6-cyclohexane dianhydride, 1,2,5, 6-naphthalene tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 4, 8-dimethyl-1, 2,3,5,6, 7-hexahydronaphthalene-1, 2,5, 6-tetracarboxylic dianhydride, 2, 6-dichloro-naphthalene-1, 4,5, 8-tetracarboxylic dianhydride or 2, 7-dichloro-naphthalene-1, 4,5, 8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5, 8-) tetrachloronaphthalene-1, 4,5,8- (or 2,3,6, 7-) tetracarboxylic dianhydride, 2,3,8, 9-perylene-tetracarboxylic dianhydride, 3,4,9, 10-perylene-tetracarboxylic dianhydride, 4,5, 11-perylene-tetracarboxylic dianhydride or 5,6,11, 12-perylene-tetracarboxylic dianhydride, cyclopentane-1, 3, 4-tetracarboxylic dianhydride, 3' -bis-4, 3' -diphenyl-tetracarboxylic dianhydride, 4, 3' -bis-phenylene dicarboxylic anhydride, 4, 3' -bis-4-diphenyl-tetracarboxylic dianhydride, 4' -bis-phenylene dicarboxylic anhydride, 4, 3' -bis-4, 5 ' -tetracarboxylic dianhydride, 4-bis-phenylene dicarboxylic anhydride, and the like.

(diamine residue)

The diamine residue contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 is preferably a diamine residue derived from a diamine compound represented by the general formula (1).

[ chemical 2]

In the formula (1), the linking group Z represents a single bond or-COO-, Y independently represents a halogen atom or a monovalent hydrocarbon having 1 to 3 carbon atoms which may be substituted with a phenyl group, an alkoxy group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, or an alkenyl group, n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4. Here, "independently" means that the plurality of substituents Y in the formula (1), and further, the integers p and q may be the same or different. Furthermore, in the formula (1), the hydrogen atoms in the terminal two amino groups may be substituted, for example, -NR ₂ R ₃ (here, R ₂ 、R ₃ Independently represents an optional substituent such as an alkyl group).

The diamine compound represented by the general formula (1) (hereinafter, sometimes referred to as "diamine (1)") is an aromatic diamine having 1 to 3 benzene rings. The diamine (1) has a rigid structure and thus has an effect of imparting an ordered structure to the polymer as a whole. Therefore, polyimide having low air permeability and low hygroscopicity can be obtained, and the moisture in the molecular chain can be reduced, so that the dielectric loss tangent can be reduced. Here, the linking group Z is preferably a single bond.

Examples of the diamine (1) include: 1, 4-diaminobenzene (p-phenylene diamine, p-PDA)), 2' -dimethyl-4, 4' -diaminobiphenyl (m-TB), 2' -n-propyl-4,4' -diaminobiphenyl (2, 2' -n-propyl-4,4' -diaminobiphen, m-NPB), 4-aminophenyl-4 ' -aminobenzoate (APAB), and the like.

The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 may contain diamine residues derived from the diamine (1) preferably 80 parts by mole or more, more preferably 85 parts by mole or more, with respect to 100 parts by mole of all diamine residues. By using the diamine (1) in an amount within the above range, the polymer as a whole is easily formed into an ordered structure by the rigid structure derived from the monomer, and a non-thermoplastic polyimide having low air permeability, low hygroscopicity and low dielectric loss factor is easily obtained.

In addition, in the case where the diamine residue derived from the diamine (1) is in the range of 80 to 85 parts by mole based on 100 parts by mole of all the diamine residues in the non-thermoplastic polyimide, 1, 4-diaminobenzene is preferably used as the diamine (1) in terms of a structure that is more rigid and excellent in-plane orientation.

As other diamine residues contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111, examples thereof include 2, 2-bis- [4- (3-aminophenoxy) phenyl ] propane, bis [4- (3-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) biphenyl ], bis [1- (3-aminophenoxy) biphenyl ], bis [4- (3-aminophenoxy) phenyl ] methane, bis [4- (3-aminophenoxy) phenyl ] ether, bis [4- (3-aminophenoxy) benzophenone, 9-bis [4- (3-aminophenoxy) phenyl ] fluorene, 2-bis- [4- (4-aminophenoxy) phenyl ] hexafluoropropane 2, 2-bis- [4- (3-aminophenoxy) phenyl ] hexafluoropropane, 3' -dimethyl-4, 4' -diaminobiphenyl, 4' -methylenedi-o-toluidine, 4' -methylenedi-2, 6-dimethylaniline, 4' -methylene-2, 6-diethylaniline 3,3' -diaminodiphenylethane, 3' -diaminobiphenyl, 3' -dimethoxybenzidine, 3' -diamino-p-terphenyl, 4' - [1, 4-phenylenebis (1-methylethylene) ] diphenylamine, 4' - [1, 3-phenylenebis (1-methylethylene) ] diphenylamine, aromatic diamine-substituted diamine-terminated aromatic diamine-substituted amino acid residues such as bis (p-aminocyclohexyl) methane, bis (p- β -amino-tert-butylphenyl) ether, bis (p- β -methyl- δ -aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1, 1-dimethyl-5-aminopentyl) benzene, 1, 5-diaminonaphthalene, 2, 6-diaminonaphthalene, 2, 4-bis (β -amino-tert-butyl) toluene, 2, 4-diaminotoluene, m-xylene-2, 5-diamine, p-xylene-2, 5-diamine, m-xylylenediamine, p-xylylenediamine, 2, 6-diaminopyridine, 2, 5-diamino-1, 3, 4-oxadiazole, piperazine, 2 '-methoxy-4, 4' -diaminobenzanilide, 1, 3-bis [2- (4-aminophenyl) -2-propyl ] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole and the like are diamine-terminated aliphatic diamine derivatives, such as dimer amino acid residues.

In the non-thermoplastic polyimide, the thermal expansion coefficient, storage elastic modulus, tensile elastic modulus, and the like can be controlled by selecting the types of the tetracarboxylic acid residue and the diamine residue, or by using the molar ratio of two or more types of the tetracarboxylic acid residue or the diamine residue. In addition, in the case of a non-thermoplastic polyimide having a plurality of structural units of polyimide, the structural units may exist in the form of blocks or may exist randomly, but from the viewpoint of suppressing the variation in-plane Retardation (RO), the structural units are preferably randomly present.

Further, it is preferable to use aromatic groups for both the tetracarboxylic acid residue and the diamine residue contained in the non-thermoplastic polyimide, because the dimensional accuracy of the polyimide film in a high-temperature environment can be improved and the amount of variation in-plane Retardation (RO) can be reduced.

The imide group concentration of the non-thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, "imide group concentration" means the imide group (- (CO) in the polyimide ₂ -N-) divided by the molecular weight of the structural whole of the polyimide. If the imide group concentration exceeds 33%, the molecular weight of the resin itself decreases, and the low hygroscopicity also deteriorates due to the increase of the polar groups. The combination of the acid anhydride and the diamine compound is selected to control the orientation of molecules in the non-thermoplastic polyimide, thereby suppressing an increase in CTE with a decrease in the imide group concentration and ensuring low hygroscopicity.

The weight average molecular weight of the non-thermoplastic polyimide is, for example, preferably in the range of 10,000 ～ 400,000, more preferably in the range of 50,000 ～ 350,000. If the weight average molecular weight is less than 10,000, the strength of the film tends to be lowered and the film tends to be fragile. On the other hand, if the weight average molecular weight exceeds 400,000, the viscosity tends to excessively increase, and defects such as uneven film thickness 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 to 100 μm, more preferably in the range of 9 μm to 50 μm, from the viewpoint of securing the function as a base layer and the handling properties at the time of manufacturing and at the time of thermoplastic polyimide coating. If the thickness of the non-thermoplastic polyimide layer 111 is less than the lower limit, electrical insulation and handleability become insufficient, and if the upper limit is exceeded, productivity is lowered.

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

In addition, from the viewpoint of suppressing warpage, the thermal expansion coefficient of the non-thermoplastic polyimide layer 111 may be in the range of 1ppm/K or more and 30ppm/K or less, preferably in the range of 1ppm/K or more and 25ppm/K or less, and more preferably in the range of 15ppm/K or more and 25ppm/K or less.

In addition, for example, other curing resin components such as plasticizers and epoxy resins, curing agents, curing accelerators, coupling agents, fillers, solvents, flame retardants, and the like may be suitably blended as optional components to the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111. However, since plasticizers contain a large amount of polar groups, which promote the diffusion of copper from copper wiring, it is preferable to use as little plasticizer as possible.

Thermoplastic polyimide layer:

the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 preferably contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine.

(tetracarboxylic acid residue)

The tetracarboxylic acid residue used in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 may be the same as that exemplified as the tetracarboxylic acid residue in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer.

(diamine residue)

The diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is preferably a diamine residue derived from a diamine compound represented by the general formulae (B1) to (B7).

[ chemical 3]

In the formulae (B1) to (B7), R ₁ Independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, the linking groups A independently represent a member selected from the group consisting of-O-; -S-, -CO-, -SO ₂ -、-COO-、-CH ₂ -、-C(CH ₃ ) ₂ Divalent radical in-NH-or-CONH-, n ₁ Independently represents an integer of 0 to 4. Wherein the repeating of the formula (B2) is removed from the formula (B3), and the repeating of the formula (B4) is removed from the formula (B5). Here, the term "independently" means one or more of the formulae (B1) to (B7) in which a plurality of linking groups A and a plurality of R are present ₁ Or a plurality of n ₁ May be the same or different. In the formulae (B1) to (B7), the hydrogen atom in the terminal two amino groups may be substituted, and may be-NR ₂ R ₃ (here, R ₂ 、R ₃ Independently represents an optional substituent such as an alkyl group).

The diamine represented by the formula (B1) (hereinafter, sometimes referred to as "diamine (B1)") is an aromatic diamine having two benzene rings. The diamine (B1) is considered to have an increased degree of freedom and high flexibility in the polyimide molecular chain, which contributes to an improvement in flexibility of the polyimide molecular chain, by having an amino group directly bonded to at least one benzene ring and a divalent linking group a in the meta position. Thus, byThe use of diamine (B1) improves the thermoplasticity of the polyimide. Here, the linking group A is preferably-O-, -CH ₂ -、-C(CH ₃ ) ₂ -、-CO-、-SO ₂ -、-S-。

Examples of the diamine (B1) include: 3,3' -diaminodiphenylmethane, 3' -diaminodiphenylpropane, 3' -diaminodiphenylsulfide, 3' -diaminodiphenylsulfone, 3' -diaminodiphenylether, 3,4' -diaminodiphenylether 3,4' -diaminodiphenylmethane, 3,4' -diaminodiphenylpropane, 3,4' -diaminodiphenylsulfide, 3' -diaminobenzophenone, (3, 3' -diamino) diphenylamine, and the like.

The diamine represented by the formula (B2) (hereinafter, sometimes referred to as "diamine (B2)") is an aromatic diamine having three benzene rings. The diamine (B2) is considered to have an increased degree of freedom and high flexibility in the polyimide molecular chain, which contributes to an improvement in flexibility of the polyimide molecular chain, by having an amino group directly bonded to at least one benzene ring and a divalent linking group a in the meta position. Therefore, by using the diamine (B2), the thermoplastic properties of the polyimide are improved. Here, the linking group A is preferably-O-.

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

The diamine represented by the formula (B3) (hereinafter, sometimes referred to as "diamine (B3)") is an aromatic diamine having three benzene rings. The diamine (B3) is considered to have a high flexibility and an increased degree of freedom in the polyimide molecular chain by the two divalent linking groups a directly bonded to one benzene ring being in the meta position with respect to each other, and contributes to an improvement in the flexibility of the polyimide molecular chain. Therefore, by using the diamine (B3), the thermoplastic properties of the polyimide are improved. Here, the linking group A is preferably-O-.

Examples of the diamine (B3) include: 1,3-Bis (4-aminophenoxy) benzene (1, 3-Bis (4-aminophenoxy) benzene, TPE-R), 1,3-Bis (3-aminophenoxy) benzene (1, 3-Bis (3-aminophenoxy) benzene, APB), 4' - [ 2-methyl- (1, 3-phenylene) dioxy ] diphenylamine, 4' - [ 4-methyl- (1, 3-phenylene) dioxy ] diphenylamine, 4' - [ 5-methyl- (1, 3-phenylene) dioxy ] diphenylamine, and the like.

The diamine represented by the formula (B4) (hereinafter, sometimes referred to as "diamine (B4)") is an aromatic diamine having four benzene rings. The diamine (B4) is considered to have high flexibility by having an amino group directly bonded to at least one benzene ring and a divalent linking group a in a meta position, and contributes to improvement of flexibility of a polyimide molecular chain. Therefore, by using the diamine (B4), the thermoplastic properties of the polyimide are improved. Here, the linking group A is preferably-O-, -CH ₂ -、-C(CH ₃ ) ₂ -、-SO ₂ -、-CO-、-CONH-。

The diamine (B4) includes: bis [4- (3-aminophenoxy) phenyl ] methane, bis [4- (3-aminophenoxy) phenyl ] propane, bis [4- (3-aminophenoxy) phenyl ] ether, bis [4- (3-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) ] benzophenone, bis [4,4' - (3-aminophenoxy) ] benzanilide, and the like.

The diamine represented by the formula (B5) (hereinafter, sometimes referred to as "diamine (B5)") is an aromatic diamine having four benzene rings. The diamine (B5) is considered to have an increased degree of freedom and a high flexibility in the polyimide molecular chain by the two divalent linking groups a directly bonded to at least one benzene ring being in the meta position with respect to each other, contributing to the improvement of the flexibility of the polyimide molecular chain. Therefore, by using the diamine (B5), the thermoplastic properties of the polyimide are improved. Here, the linking group A is preferably-O-.

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

The diamine represented by the formula (B6) (hereinafter, sometimes referred to as "diamine (B6)") is an aromatic diamine having four benzene rings. The diamine (B6) is considered to have high flexibility by having at least two ether bonds, which contributes to the improvement of flexibility of the polyimide molecular chain. Therefore, by using the diamine (B6), the thermoplastic properties of the polyimide are improved. Here, as the linking group A, it is preferably-C (CH) ₃ ) ₂ -、-O-、-SO ₂ -、-CO-。

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

The diamine represented by the formula (B7) (hereinafter, sometimes referred to as "diamine (B7)") is an aromatic diamine having four benzene rings. The diamine (B7) has a divalent linking group a having high flexibility on both sides of the diphenyl skeleton, and thus is considered to contribute to the improvement of flexibility of the polyimide molecular chain. Therefore, by using the diamine (B7), the thermoplastic properties of the polyimide are improved. Here, the linking group A is preferably-O-.

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

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 may contain a diamine residue derived from at least one diamine compound selected from the diamines (B1) to (B7) in a range of 60 parts by mol or more and preferably 60 parts by mol or more and 99 parts by mol or less, more preferably 70 parts by mol or more and 95 parts by mol or less, based on 100 parts by mol of all diamine residues. Since the diamines (B1) to (B7) have a molecular structure having flexibility, the use of at least one diamine compound selected from these compounds in an amount within the above range can improve the flexibility of polyimide molecular chains and impart thermoplasticity. If the total amount of the diamines (B1) to (B7) in the raw material is less than 60 parts by mole based on 100 parts by mole of all diamine components, the polyimide resin is insufficient in flexibility and sufficient thermoplasticity cannot be obtained.

The diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is preferably a diamine residue derived from a diamine compound represented by the general formula (1). The diamine compound [ diamine (1) ] represented by the formula (1) is as described in the description of the non-thermoplastic polyimide. The diamine (1) has a rigid structure and has an effect of imparting an ordered structure to the whole polymer, and therefore can reduce the dielectric loss tangent or hygroscopicity by suppressing the movement of molecules. Further, when the polyimide is used as a raw material for a thermoplastic polyimide, a polyimide having low air permeability and excellent heat-resistant adhesion over a long period of time can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 may contain a diamine residue derived from the diamine (1) in a range of preferably 1 to 40 parts by mole, more preferably 5 to 30 parts by mole. By using the diamine (1) in an amount within the above range, the polymer as a whole forms an ordered structure by the rigid structure derived from the monomer, and thus a polyimide which is thermoplastic, low in air permeability and hygroscopicity, and excellent in heat-resistant adhesion over a long period of time can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 may contain a diamine residue derived from a diamine compound other than the diamine (1) and the diamines (B1) to (B7) within a range that does not impair the effects of the invention.

In the thermoplastic polyimide, the thermal expansion coefficient, tensile elastic modulus, glass transition temperature, and the like can be controlled by selecting the types of the tetracarboxylic acid residue and the diamine residue, or by using the molar ratio of two or more types of the tetracarboxylic acid residue or the diamine residue. In addition, in the case of a thermoplastic polyimide having a plurality of structural units of polyimide, the structural units may exist in the form of blocks or may exist randomly, but preferably exist randomly.

Further, by setting 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 the amount of variation in-plane Retardation (RO) can be suppressed.

The imide group concentration of the thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, "imide group concentration" means the imide group (- (CO) in the polyimide ₂ -N-) divided by the molecular weight of the structural whole of the polyimide. If the concentration of the imide groups exceeds When the amount is 33%, the molecular weight of the resin itself decreases, and the low hygroscopicity also deteriorates due to the increase of the polar groups. The diamine compound is selected in combination to control the molecular orientation of the thermoplastic polyimide, thereby suppressing an increase in CTE associated with a decrease in the imide group concentration and ensuring low hygroscopicity.

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

The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 is, for example, an adhesive layer in an insulating resin of a circuit board, and therefore, is most preferably a structure that is completely imidized in order to suppress copper diffusion. Among them, a part of polyimide may be amic acid. The imidization ratio was determined by measuring the infrared absorption spectrum of a polyimide film by the primary reflection attenuated total reflection (Attenuated Total Reflectance, ATR) method using a Fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by Japanese Spectroscopy), thereby measuring 1015cm ^-1 The benzene ring absorber in the vicinity is based on 1780cm ^-1 C=o of imide group of (C) is calculated.

From the viewpoint of securing adhesion performance, the thickness of the thermoplastic polyimide layer 112 is preferably in the range of 1 μm or more and 10 μm or less, more preferably in the range of 1 μm or more and 5 μm or less. When the thickness of the thermoplastic polyimide layer 112 is less than the lower limit, the adhesiveness is insufficient, and when the upper limit is exceeded, the dimensional stability tends to be deteriorated.

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

In addition, in addition to polyimide, other curing resin components such as plasticizers and epoxy resins, curing agents, curing accelerators, inorganic fillers, coupling agents, fillers, solvents, flame retardants, and the like may be suitably blended as optional components in the resin used for the thermoplastic polyimide layer 112. However, since plasticizers contain a large amount of polar groups, which promote the diffusion of copper from copper wiring, it is preferable to use as little plasticizer as possible.

In the metal-clad laminate 100, the thermal expansion coefficient of the entire of the two polyimide layers 110 and the adhesive polyimide layer 120 may be 10ppm/K or more, preferably 10ppm/K or more and 30ppm/K or less, and more preferably 15ppm/K or more and 25ppm/K or less, in order to secure dimensional stability after circuit processing.

In the metal-clad laminate 100, the total thickness T1 of the two polyimide layers 110 and the adhesive polyimide layer 120, the thickness T2 of the adhesive polyimide layer 120, and the ratio (T2/T1) of the thickness T2 of the adhesive polyimide layer 120 to the total thickness T1 are as described with reference to fig. 1.

(Synthesis of polyimide)

The polyimide constituting the polyimide layer 110 can be produced by reacting the acid anhydride with a diamine in a solvent and then heating to ring-close the reaction product after the precursor resin is produced. For example, a polyamide acid as a polyimide precursor can be obtained by dissolving an acid anhydride component and a diamine component in an organic solvent in substantially equal molar amounts, and stirring the mixture at a temperature in the range of 0 to 100 ℃ for 30 minutes to 24 hours to carry out polymerization. In the reaction, the reaction components are dissolved so that the amount of the precursor to be formed is in the range of 5 to 30 wt%, preferably 10 to 20 wt%, in the organic solvent. Examples of the organic solvent used in the polymerization reaction include: n, N-dimethylformamide, N-dimethylacetamide (N, N-dimethyl acetamide, DMAc), N-methyl-2-pyrrolidone, 2-butanone, dimethyl sulfoxide, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme (diglyme), triglyme, and the like. These solvents may be used in combination of two or more kinds, and further, aromatic hydrocarbons such as xylene and toluene may be used in combination. The amount of the organic solvent used is not particularly limited, but is preferably adjusted so that the concentration of the polyamic acid solution (polyimide precursor solution) obtained by polymerization is about 5 to 30% by weight.

In the synthesis of polyimide, only one of the acid anhydride and the diamine may be used, or two or more of them may be used in combination. The thermal expansion, the adhesiveness, the glass transition temperature, and the like can be controlled by selecting the types of the acid anhydride and the diamine, or by using the molar ratio of the two or more acid anhydrides or diamines.

The synthesized precursors are generally advantageously used as reaction solvent solutions, but may be concentrated, diluted or replaced with other organic solvents as desired. In addition, the precursor is generally excellent in solvent solubility, and thus can be advantageously used. The method of imidizing the precursor is not particularly limited, and for example, the following heat treatment can be preferably employed: heating in the solvent at 80-400 deg.c for 1-24 hr.

[ Circuit Board ]

The metal-clad laminate 100 is mainly useful as a circuit board material such as FPC, rigid, and flexible circuit board. That is, by patterning one or both of the two metal layers 101 of the metal-clad laminate 100 by a conventional method to form a wiring layer, a circuit board such as an FPC, which is an embodiment of the present invention, can be manufactured. Although not shown, the circuit board includes a resin laminate in which a first insulating resin layer (P1), an adhesive layer (B), and a second insulating resin layer (P2) are laminated in this order, and a wiring layer provided on one or both surfaces of the resin laminate.

Examples (example)

The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, various measurements and evaluations were as follows.

[ measurement of dielectric constant and dielectric loss tangent ]

The dielectric constant (Dk) and dielectric loss tangent (Df) of the polyimide film at 10GHz were measured using a vector network analyzer (manufactured by Agilent, inc., trade name E8363C) and a separation medium resonator (split post dielectric resonator, SPDR). Further, the materials used in the measurement are at the temperature: the material is placed for 24 hours under the conditions of 24-26 ℃ and humidity of 45-55%RH.

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

Regarding the storage modulus of elasticity of the adhesive layer, the adhesive layer (thickness 50 m) was peeled off from the base film and cut into 5mm×20mm, and heated in an oven at 120 ℃ for 2 hours and at 170 ℃ for 3 hours. The obtained sample was subjected to stepwise heating at a heating rate of 4℃per minute from 30℃to 400℃using a dynamic viscoelasticity measuring apparatus (DMA: manufactured by UBM Co., ltd.; trade name: E4000F), and measured at a frequency of 1 Hz. The maximum temperature at which the Tan δ value in the measurement was maximum was defined as Tg.

[ measurement of dimensional Change Rate ]

The dimensional change rate was measured in the following manner. First, a dry film resist was exposed to light and developed at 100mm intervals using a 150mm square test piece, thereby forming a target for position measurement. After measuring the size before etching (normal state) in an atmosphere having a temperature of 23.+ -. 2 ℃ and a relative humidity of 50.+ -. 5%, copper other than the target of the test piece was removed by etching (liquid temperature of 40 ℃ C. Or less and time of 10 minutes or less). After standing at 23.+ -. 2 ℃ in an atmosphere having a relative humidity of 50.+ -. 5% for 24.+ -. 4 hours, the etched dimensions were measured. The dimensional change rate with respect to the normal state was calculated for each of the MD direction (longitudinal direction) and the TD direction (width direction), and the average value of each was used as the dimensional change rate after etching. The post-etching dimensional change rate is calculated by the following equation.

Post-etching dimensional change ratio (%) = (B-ase:Sub>A)/a×100

A: inter-target distance before etching

B: inter-target distance after etching

Next, the test piece was heat-treated in an oven at 250℃for 1 hour, and the distance between the position targets after that was measured. The dimensional change rate after etching was calculated for each of 3 points in the MD direction (longitudinal direction) and the TD direction (width direction), and the average value of each was used as the dimensional change rate after heat treatment. The dimensional change rate after heating was calculated by the following equation.

Dimensional change after heating (%) = (C-B)/b×100

B: inter-target distance after etching

C: distance between targets after heating

The abbreviations used in this example represent the following compounds.

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

PMDA: pyromellitic dianhydride

BTDA:3,3', 4' -benzophenone tetracarboxylic dianhydride

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

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

bis-aniline-M: 1, 3-bis [2- (4-aminophenyl) -2-propyl ] benzene

DDA: manufactured by the company GmbH (Croda Japan) Inc. (trade name: pu Li An (PRIAMINE) 1075)

N-12: dodecanedioic acid dihydrazide

DMAc: n, N-dimethylacetamide

R710: ( Trade name, p Lin Taike (Printec) (strand), bisphenol type epoxy resin, epoxy equivalent: 170. liquid state at normal temperature, weight average molecular weight: about 340 of )

VG3101L: ( Trade name, p Lin Taike (Printec) (strand), multifunctional epoxy, epoxy equivalent: 210. softening point: 39-46 DEG C )

SR35K: ( Trade name, manufactured by p Lin Taike (Printec) stock, epoxy resin, epoxy equivalent: 930-940, softening point: 86-98 deg.C )

YDCN-700-10: (trade name, manufactured by Nippon Ten Chemie Co., ltd., cresol novolak type epoxy resin, epoxy equivalent 210, softening point 75 ℃ -85 ℃ C.)

Mi Laisi (milex) XLC-LL: ( Trade name, three-well chemical (strand) manufacture, phenolic resin, hydroxyl equivalent: 175. softening point: 77 ℃, water absorption: 1 mass%, heating mass reduction rate: 4 mass% )

HE200C-10: ( Trade name, air water (strand) manufacture, phenolic resin, hydroxyl equivalent: 200. softening point: 65-76 ℃ and water absorption rate: 1 mass%, heating mass reduction rate: 4 mass% )

HE910-10: ( Trade name, air water (strand) manufacture, phenolic resin, hydroxyl equivalent: 101. softening point: 83 ℃, water absorption: 1 mass%, heating mass reduction rate: 3 mass% )

SC1030-HJA: ( Trade name, manufactured by Admatechs (strands), silica filler dispersion, average particle size: 0.25 μm )

Ai Luoxi mol (Aerosil) R972: ( Trade name, manufactured by japan Ai Luoxi mol (Aerosil) (strand), silica, average particle size: 0.016 μm )

Acrylic rubber HTR-860P-30B-CHN: ( Sample name, empire chemical industry (strand) manufacture, weight average molecular weight: 23 ten thousand, glycidyl functional monomer ratio: 8%, tg: -7 DEG C )

Acrylic rubber HTR-860P-3CSP: ( Sample name, empire chemical industry (strand) manufacture, weight average molecular weight: 80 ten thousand, glycidyl functional monomer ratio: 3%, tg: -7 DEG C )

A-1160: (trade name, manufactured by GE Toshiba (Strand) gamma-ureidopropyltriethoxysilane)

A-189: (trade name, manufactured by GE Toshiba (Strand)), gamma-mercaptopropyl trimethoxysilane

Kularrol (Curezol) 2PZ-CN: (trade name, manufactured by four chemical industries (Stra)), 1-cyanoethyl-2-phenylimidazole

RE-810NM: ( Trade name, diallyl bisphenol a diglycidyl ether manufactured by japan chemical Co., ltd., properties: liquid form )

Fullett (PHORET) SCS: ( Trade name, acrylic polymer containing styrene group, tg manufactured by holly research chemical Co., ltd.: weight average molecular weight at 70 ℃): 15000 )

BMI-1: (trade name, manufactured by Tokyo chemical Co., ltd., 4' -bismaleimide diphenylmethane)

TPPK: (trade name, manufactured by Tokyo chemical Co., ltd., tetraphenylphosphonium tetraphenylborate)

HP-P1: (trade name, manufactured by Water island alloy iron Co., ltd., boron nitride filler)

NMP: (N-methyl-2-pyrrolidone manufactured by Kandong chemical Co., ltd.)

Synthesis example 1

Preparation of resin solution A for adhesive layer

Cyclohexanone was added to a composition containing (a) an epoxy resin and a phenol resin as thermosetting resins and (c) an inorganic filler in the composition names and composition ratios (unit: parts by mass) shown in Table 1, and the mixture was stirred and mixed. To this, an acrylic rubber as a high molecular weight component (b) shown in Table 1 was added and stirred, and further a coupling agent (e) and a hardening accelerator (d) shown in Table 1 were added and stirred until each component was uniform, to obtain a resin solution A for an adhesive layer.

TABLE 1

Synthesis example 2

Synthesis of polyimide resin (PI-1) and preparation of resin solution B for adhesive layer

A300 mL flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen inlet tube was charged with 15.53g of 1, 3-bis (3-aminopropyl) tetramethyldisiloxane (trade name: LP-7100, manufactured by Xinyue chemical industry Co., ltd.), 28.13g of polyoxypropylene diamine (trade name: D400, molecular weight: 450, manufactured by Basf Co., ltd.), and 100.0g of NMP, and stirred to prepare a reaction solution. After the diamine was dissolved, 32.30g of 4,4' -oxydiphthalic anhydride purified by recrystallization from acetic anhydride was added little by little to the reaction solution while the flask was cooled in an ice bath. After the reaction was carried out at normal temperature (25 ℃) for 8 hours, 67.0g of xylene was added, and the mixture was heated at 180℃while blowing nitrogen gas, whereby xylene was azeotropically removed together with water. The reaction solution was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain a polyimide resin (PI-1). The molecular weight of the obtained polyimide resin (PI-1) was measured by gel permeation chromatography (Gel Permeation Chromatography, GPC), and as a result, the number average molecular weight mn=22400 and the weight average molecular weight mw= 70200 were counted in terms of polystyrene.

Using the polyimide resin (PI-1) thus obtained, each component was blended at a composition ratio (unit: parts by mass) shown in Table 2 to obtain a resin solution B for an adhesive layer.

TABLE 2

Differentiation of	Name of the name	Synthesis example 2
			Thermoplastic resin	PI-1	100
Reactive plasticizers	RE-810NM	40
			Compounds having styryl groups	Fullett (PHORET) SCS	40
Compounds having maleimide groups	BMI-1	40
			Hardening accelerator	TPPK	0.2
Inorganic filler	HP-P1	22
			Solvent(s)	NMP	270

Synthesis example 3

Preparation of polyamic acid solution for insulating resin layer

Under a nitrogen stream, 64.20g of M-TB (0.302 mol) and 5.48g of bisaniline-M (0.016 mol) and DMAc in an amount of 15% by weight of the solid content concentration after the polymerization were charged into the reaction vessel, and dissolved by stirring at room temperature. Next, after 34.20g of PMDA (0.157 mol) and 46.13g of BPDA (0.157 mol) were added, the polymerization was continued with stirring at room temperature for 3 hours to prepare a polyamic acid solution 1 (viscosity: 26,500 cps).

Synthesis example 4

Preparation of polyamic acid solution for insulating resin layer

A polyamic acid solution 2 (viscosity: 2,650 cps) was produced in the same manner as in Synthesis example 3, except that 69.56g of m-TB (0.328 mol), 542.75g of TPE-R (1.857 mol), DMAc in an amount of 12% by weight in terms of solid content concentration after polymerization, 194.39g of PMDA (0.891 mol) and 393.31g of BPDA (1.337 mol) were each composed as a raw material.

Production example 1

Preparation of adhesive layer resin sheet A

The adhesive layer resin solution a was applied to a silicone-treated surface of a release substrate (vertical×horizontal×thickness=320 mm×240mm×25 μm) so as to have a thickness of 50 μm after drying, and then heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 15 minutes, and then peeled off from the release substrate, whereby a resin sheet a was produced. In addition, in order to evaluate the physical properties of the resin sheet a after curing, the resin sheet a was heated in an oven at 120 ℃ for 2 hours and at 170 ℃ for 3 hours. After that, the Tg of the cured resin sheet A was 95℃and the storage elastic modulus at 50℃was 960MPa, and the maximum value of the storage elastic modulus at 180℃to 260℃was 7MPa.

Production example 2

Preparation of adhesive layer resin sheet B

The adhesive layer resin solution B was applied to a silicone-treated surface of a release substrate (vertical×horizontal×thickness=320 mm×240mm×25 μm) so as to have a thickness of 50 μm after drying, and then heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 15 minutes, and then peeled off from the release substrate, whereby a resin sheet B was produced. In addition, in order to evaluate the physical properties of the resin sheet B after curing, the resin sheet B was heated in an oven at 120 ℃ for 2 hours and at 170 ℃ for 3 hours. After that, the Tg of the cured resin sheet B is 100 ℃ or less, the storage elastic modulus at 50 ℃ is 1800MPa or less, and the maximum value of the storage elastic modulus at 180-260 ℃ is 70MPa.

Production example 3

Preparation of single-sided metal-clad laminate

The polyamic acid solution 2 was uniformly applied to the copper foil 1 (electrolytic copper foil, thickness: 12 μm, surface roughness Rz on the resin layer side: 0.6 μm) so that the thickness after curing became about 2 μm to 3 μm, and then dried by heating at 120℃to remove the solvent. Next, the polyamic acid solution 1 was uniformly applied so that the thickness after curing became about 21 μm, and the solution was dried by heating at 120 ℃. Further, the polyamic acid solution 2 was uniformly applied so that the thickness after curing became about 2 μm to 3 μm, and then dried by heating at 120℃to remove the solvent. Further, a stepwise heat treatment was performed from 120 ℃ to 360 ℃ to complete imidization, thereby producing a single-sided metal-clad laminate 1. The dimensional change rate of the single-sided metal-clad laminate 1 is as follows.

Post-etching dimensional change ratio in MD direction (long side direction): 0.01%

Post-etching dimensional change ratio in TD direction (width direction): -0.04%

Dimensional change after heating in MD direction (long side direction): -0.03%

Dimensional change ratio after heating in TD direction (width direction): -0.01%

Preparation of polyimide film

Copper foil 1 of single-sided metal clad laminate 1 was etched away using an aqueous solution of ferric chloride to prepare polyimide film 1 (thickness: 25 μm, CTE:20ppm/K, dk:3.40, df: 00029).

Example 1

2 single-sided metal clad laminate plates 1 were prepared, and the respective insulating resin layer side surfaces were overlapped with both surfaces of the resin sheet a, and pressure was applied at 180 ℃ for 2 hours under 3.5MPa to perform pressure bonding, thereby preparing metal clad laminate plates 1. The evaluation results of the metal-clad laminate 1 are as follows.

Post-etch dimensional change rate in MD: -0.02%

Post-etch dimensional change rate in TD direction: -0.03%

Dimensional change after heating in MD: -0.02%

Dimensional change rate after heating in TD direction: -0.02%

The metal-clad laminate 1 is free from warpage and dimensional change. The CTE of the resin laminate 1 (thickness: 100 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 1 was 24.1ppm/K.

Example 2

2 single-sided metal clad laminate plates 1 were prepared, and the respective insulating resin layer side surfaces were overlapped with the two surfaces of the resin sheet B, and pressure was applied at 180 ℃ for 2 hours under 3.5MPa to perform pressure bonding, thereby preparing metal clad laminate plates 2. The evaluation results of the metal-clad laminate 2 are as follows.

Post-etch dimensional change rate in MD: -0.05%

Post-etch dimensional change rate in TD direction: -0.05%

Dimensional change after heating in MD: -0.03%

Dimensional change rate after heating in TD direction: -0.04%

The metal-clad laminate 2 is free from warpage and dimensional change. The CTE of the resin laminate 2 (thickness: 100 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 2 was 23.3ppm/K.

Comparative example 1

A metal-clad laminate 3 was produced in the same manner as in example 1, except that a fluororesin sheet (trade name: adhesive perfluoro resin EA-2000, thickness: 50 μm, tm:303 ℃ C., tg: none) was used instead of the resin sheet A, and the laminate was pressure-bonded at 320 ℃ C. For 5 minutes under a pressure of 3.5 MPa.

The evaluation results of the metal-clad laminate 3 are as follows.

Post-etch dimensional change rate in MD: -0.11%

Post-etch dimensional change rate in TD direction: -0.13%

Dimensional change after heating in MD: -0.19%

Dimensional change rate after heating in TD direction: -0.20%

The metal-clad laminate 3 is free from warpage and dimensional change. The CTE of the resin laminate 3 (thickness: 100 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 3 was 27.6ppm/K.

Reference example 1

The copper foil 1, the resin sheet a, the polyimide film 1, the resin sheet a and the copper foil 1 were stacked in this order, and pressure was applied at 180 ℃ for 2 hours under 3.5MPa to prepare a metal-clad laminate 4.

The evaluation results of the metal-clad laminate 4 are as follows.

Post-etch dimensional change rate in MD: -0.04%

Post-etch dimensional change rate in TD direction: -0.05%

Dimensional change after heating in MD: -0.12%

Dimensional change rate after heating in TD direction: -0.14%

The metal-clad laminate 4 is free from warpage and dimensional change. The CTE of the resin laminate 4 (thickness: 100 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 4 was 23.9ppm/K.

It is understood that the dimensional change rate after etching and the dimensional change rate after heating were low in example 1 and example 2, respectively, compared with comparative example 1 and reference example 1. In comparative example 1, lamination by thermocompression bonding at 320℃was performed without any problem in the adhesion, but sufficient adhesion could not be obtained by thermocompression bonding under the same thermocompression bonding conditions (temperature: 180℃for 2 hours, and pressure: 3.5 MPa) as in examples 1 and 2. Reference example 1 was also performed for verification of the position configuration of the resin sheet a.

Example 3

A single-sided metal clad laminate 1 was prepared, and after the adhesive layer resin solution a was applied to the surface of the insulating resin layer side so that the thickness thereof was 50 μm after drying, the adhesive layer was heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 15 minutes, to prepare a single-sided metal clad laminate 1 with an adhesive layer.

Next, the adhesive layer surface of the single-sided metal-clad laminate 1 with the adhesive layer was overlapped with the insulating resin layer side surface of the other single-sided metal-clad laminate 1, and then, a pressure of 3.5MPa was applied at 180 ℃ for 2 hours to perform pressure bonding, thereby preparing a metal-clad laminate 1'.

The evaluation results of the metal-clad laminate 1' are as follows.

Post-etch dimensional change rate in MD: -0.03%

Post-etch dimensional change rate in TD direction: -0.03%

Dimensional change after heating in MD: -0.02%

Dimensional change rate after heating in TD direction: -0.02%

The metal-clad laminate 1' is free from warpage and dimensional change. The CTE of the resin laminate 1 '(thickness: 100 μm) prepared by etching and removing the copper foil 1 in the metal-clad laminate 1' was 23.1ppm/K.

Example 4

2 single-sided metal clad laminate plates 1 with adhesive layers were prepared, the adhesive layers were stacked on each other, and then, a pressure of 3.5MPa was applied at 180 ℃ for 2 hours to perform pressure bonding, thereby preparing metal clad laminate plates 5.

The evaluation results of the metal-clad laminate 5 are as follows.

Post-etch dimensional change rate in MD: -0.03%

Post-etch dimensional change rate in TD direction: -0.03%

Dimensional change after heating in MD: -0.03%

Dimensional change rate after heating in TD direction: -0.03%

The metal-clad laminate 5 is free from warpage and dimensional change. The CTE of the resin laminate 5 (thickness: 150 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 5 was 23.8ppm/K.

Example 5

A single-sided metal clad laminate 1 was prepared, and an adhesive layer resin solution a was applied to the surface of the insulating resin layer side so that the thickness thereof was 75 μm after drying, and then heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 25 minutes, to prepare a single-sided metal clad laminate 2 with an adhesive layer.

2 single-sided metal clad laminate plates 2 with adhesive layers were prepared, the adhesive layers were stacked on each other, and then, a pressure of 3.5MPa was applied at 180 ℃ for 2 hours to perform pressure bonding, thereby preparing metal clad laminate plates 6.

The evaluation results of the metal-clad laminate 6 are as follows.

Post-etch dimensional change rate in MD: -0.01%

Post-etch dimensional change rate in TD direction: -0.01%

Dimensional change after heating in MD: 0.01%

Dimensional change rate after heating in TD direction: 0.02%

The metal-clad laminate 6 is free from warpage and dimensional change. The CTE of the resin laminate 6 (thickness: 200 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 6 was 22.8ppm/K.

Synthesis example 5

A500 ml separable flask was charged with 44.98g of BTDA (0.139 mol), 75.02g of DDA (0.140 mol), 168g of NMP and 112g of xylene under a nitrogen stream, and the mixture was thoroughly mixed at 40℃for 30 minutes to prepare a polyamic acid solution. The polyamic acid solution was heated to 190℃and stirred with heating for 4.5 hours, and 112g of xylene was added to prepare an imidized polyimide adhesive solution 1. The solid content in the obtained polyimide adhesive solution 1 was 29.1% by weight, and the viscosity was 7,800cps. The polyimide had a weight average molecular weight (Mw) of 87,700.

Synthesis example 6

The polyimide adhesive solution 1 obtained in Synthesis example 5 was prepared by mixing 34.4g (solid content: 10 g) with 1.25g of N-12 and 2.5g of Exolit OP935 (manufactured by Clariant Japan Co., ltd.), and diluting with 1.297g of NMP and 3.869g of xylene to prepare an adhesive layer resin solution C.

Preparation of adhesive layer resin sheet C

The adhesive layer resin solution C was applied to the silicone-treated surface of the release substrate (vertical×horizontal×thickness=320 mm×240mm×25 μm) so as to have a thickness of 50 μm after drying, and then heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 15 minutes, and then peeled off from the release substrate, whereby a resin sheet C was produced. In addition, in order to evaluate the physical properties of the resin sheet C after curing, the resin sheet D after curing was prepared by heating in an oven at 120 ℃ for 2 hours and at 170 ℃ for 3 hours. The Tg of the cured resin sheet D was 95℃and the storage elastic modulus at 50℃was 1220MPa, and the maximum value of the storage elastic modulus at 180℃to 260℃was 26MPa.

Example 6

A single-sided metal clad laminate 1 was prepared, and an adhesive layer resin solution C was applied to the surface of the insulating resin layer side so that the thickness thereof was 50 μm after drying, and then heated and dried at 80 ℃ for 15 minutes, and further dried at 120 ℃ for 15 minutes, to prepare a single-sided metal clad laminate 3 with an adhesive layer.

Next, the adhesive layer surface of the single-sided metal-clad laminate 3 with the adhesive layer was overlapped with the insulating resin layer side surface of the single-sided metal-clad laminate 1, and then, a pressure of 3.5MPa was applied at 180 ℃ for 2 hours to perform pressure bonding, thereby preparing a metal-clad laminate 7.

The evaluation results of the metal-clad laminate 7 are as follows.

Post-etch dimensional change rate in MD: -0.02%

Post-etch dimensional change rate in TD direction: -0.02%

Dimensional change after heating in MD: -0.03%

Dimensional change rate after heating in TD direction: -0.03%

The metal-clad laminate 7 is free from warpage and dimensional change. The CTE of the resin laminate 7 (thickness: 100 μm) produced by etching and removing the copper foil 1 in the metal-clad laminate 7 was 23.4ppm/K.

The single-sided metal-clad laminate with an adhesive layer described in the embodiment can also be applied to the production of a multilayer circuit board. In this case, the thickness of the adhesive layer is preferably 100 μm or less, and the thickness ratio of the adhesive layer in the insulating resin layer is preferably 80% or less.

The embodiments of the present invention have been described in detail for the purpose of illustration, but the present invention is not limited to the embodiments and various modifications are possible.

Claims

1. A metal clad laminate comprising:

an adhesive layer disposed 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, wherein the metal-clad laminate is characterized in that:

the total thickness T1 of the first insulating resin layer, the adhesive layer and the second insulating resin layer is in the range of 70 [ mu ] m to 500 [ mu ] m, and the ratio (T2/T1) of the thickness T2 of the adhesive layer to the total thickness T1 is in the range of 0.5 to 0.8,

the adhesive layer is composed of a thermoplastic resin or a thermosetting resin, and satisfies the following conditions (i) to (iii):

(i) The storage elastic modulus at 50 ℃ is below 1800 MPa;

(iii) The glass transition temperature is 180 ℃ or lower.

2. The metal-clad laminate according to claim 1, wherein the first insulating resin layer and the second insulating resin layer each 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 adhesive layer is disposed in contact with two of the thermoplastic polyimide layers, wherein

The non-thermoplastic polyimide in the non-thermoplastic polyimide layer means that the storage elastic modulus at 30 ℃ measured using a dynamic mechanical analyzer is 1.0X10 ⁹ Storage elastic modulus at 350 ℃ of Pa or more of 1.0X10 ⁸ Polyimide of Pa or more;

the thermoplastic polyimide in the thermoplastic polyimide layer means that the storage elastic modulus at 30 ℃ measured by using a dynamic mechanical analyzer is 1.0X10 ⁹ The storage elastic modulus at 350 ℃ of Pa or more is less than 1.0X10 ⁸ Polyimide of Pa.

3. The metal-clad laminate according to claim 2, wherein the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains tetracarboxylic acid residues and diamine residues, and the content of diamine residues derived from a diamine compound represented by the following general formula (1) is 80 parts by mole or more based on 100 parts by mole of all diamine residues:

4. The metal-clad laminate according to any one of claims 1 to 3, wherein a thermal expansion coefficient of the entirety of the first insulating resin layer, the adhesive layer, and the second insulating resin layer is in a range of 10ppm/K or more and 30ppm/K or less.

5. A metal clad laminate according to any one of claims 1 to 3, wherein the first metal layer and the second metal layer each comprise copper foil.

6. The metal-clad laminate of claim 4 wherein the first metal layer and the second metal layer each comprise copper foil.

7. A circuit board obtained by processing the first metal layer and/or the second metal layer of the metal-clad laminate according to any one of claims 1 to 6 into wiring.