JP2020055299A - Metal-clad laminated plate and circuit board - Google Patents

Abstract

To provide a metal-clad laminated plate and a circuit board which can reduce a transmission loss even in high-frequency transmission and are excellent in dimensional stability.SOLUTION: A metal-clad laminated plate includes: a first one-side metal-clad laminated plate having a first metal layer and a first insulating resin layer stacked on at least one surface of the first metal layer; a second one-side metal-clad laminated plate having a second metal layer and a second insulating resin stacked on at least one surface of the second metal layer; and an adhesive layer which is arranged so as to be in contact with the first insulating resin layer and the second insulating resin layer and is stacked between the first one-side metal-clad laminated plate and the second one-side metal-clad laminated plate. The adhesive layer is composed of a thermoplastic resin or a thermosetting resin, and satisfies (i) a storage elastic modulus at 50°C of 1,800 MPa or less; (ii) a maximum value of storage elastic modulus in a temperature region of 180-260°C of 800 MPa or less; and (iii) a glass transition temperature (Tg) of 180°C or lower.SELECTED DRAWING: None

Description

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

  2. Description of the Related Art In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed wiring board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even when repeatedly bent. Circuits) is increasing in demand. Since FPCs can be mounted three-dimensionally and at high density even in a limited space, their applications are expanding to, for example, wiring of movable parts of electronic devices such as HDDs, DVDs and smartphones, and components such as cables and connectors. I am doing it.

  In addition to the above-described high density, as the performance of the device has been improved, it is necessary to cope with a higher frequency of a transmission signal. If a transmission loss in a transmission path is large when transmitting a high-frequency signal, inconveniences such as a loss of an electric signal and a long signal delay time occur. Therefore, reduction of transmission loss will be important in FPCs in the future. In order to cope with high-frequency signal transmission, a material having a dielectric layer of a liquid crystal polymer having a lower dielectric constant and a lower dielectric loss tangent is used instead of polyimide which is widely used as an FPC material. However, although the liquid crystal polymer has excellent dielectric properties, there is room for improvement in heat resistance and adhesion to a metal layer.

  Further, fluororesins are also known as polymers having a low dielectric constant and a low dielectric loss tangent. For example, as an FPC material capable of supporting high-frequency signal transmission and having excellent adhesion, a polyimide adhesive film having a thermoplastic polyimide layer and a high heat-resistant polyimide layer on both surfaces of a fluorine-based resin layer, respectively, is attached. An insulating film has been proposed (Patent Document 1). The insulating film of Patent Document 1 is excellent in dielectric properties because it uses a fluorine-based resin, but has a problem in dimensional stability. Especially when applied to FPC, before and after circuit processing by etching. There is a concern that the dimensional change of the will increase. Therefore, it is difficult to increase the thickness of the fluororesin and to increase the thickness ratio.

  By the way, as a technique relating to an adhesive layer used for an electronic material, application of a resin composition containing an epoxy resin and a phenoxy resin or a resin composition containing a thermoplastic polyimide and a maleimide compound to an adhesive sheet has been proposed (Patent Reference 2, Patent Document 3). The film-like adhesive sheets of Patent Documents 2 and 3 have an advantage of having a low glass transition temperature and exhibiting high adhesiveness to a laminated material. However, Patent Documents 2 and 3 do not discuss the possibility of application to high-frequency signal transmission or the application to an adhesive layer in a metal-clad laminate.

JP 2017-24265 A Japanese Patent No. 6191800 Japanese Patent No. 55553108

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

  Means for Solving the Problems As a result of intensive studies, the present inventors 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 for a metal-clad laminate, and have completed the present invention.

A metal-clad laminate of the present invention includes a first metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one surface of the first metal layer. ,
A second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one surface of the second metal layer;
The first single-sided metal-clad laminate and the second single-sided metal-clad laminate were disposed so as to be in contact with the first insulating resin layer and the second insulating resin layer. And a bonding layer.
In the metal-clad laminate of the present invention, the adhesive layer is made of a thermoplastic resin or a thermosetting resin, and has the following conditions (i) to (iii);
(I) the storage modulus at 50 ° C. is 1800 MPa or less;
(Ii) the maximum value of the storage modulus in a temperature range of 180 ° C. to 260 ° C. is 800 MPa or less;
(Iii) the glass transition temperature (Tg) is 180 ° C. or less;
Meet.

  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 to 500 μm, and The ratio (T2 / T1) of the thickness T2 of the adhesive layer to 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 is a multilayer in which a thermoplastic polyimide layer, a non-thermoplastic polyimide layer, and a thermoplastic polyimide layer are laminated in this order. May have a structure,
The adhesive layer may be provided in contact with the two thermoplastic polyimide layers.

  In the metal-clad laminate of the present invention, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains a tetracarboxylic acid residue and a diamine residue. The content of the diamine residue derived from the diamine compound represented by the formula (1) may be 80 mol parts or more.

  In the formula (1), the linking group Z represents a single bond or —COO—, and Y independently represents a monovalent hydrocarbon having 1 to 3 carbon atoms which may be substituted with a halogen atom or a phenyl group, or Represents an alkoxy group having 1 to 3 or 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, even if the total thermal expansion coefficient of the first insulating resin layer, the adhesive layer, and the second insulating resin layer is in the range of 10 ppm / K or more and 30 ppm / K or less. Good.

  In the metal-clad laminate of the present invention, both the first metal layer and the second metal layer may be made of copper foil.

  The circuit board of the present invention is obtained by processing the first metal layer and / or the second metal layer in any one of the above metal-clad laminates into wiring.

  The metal-clad laminate of the present invention enables the thickness of the insulating resin layer to be increased by a structure in which two single-sided metal-clad laminates are adhered to each other with an adhesive layer having a specific parameter interposed therebetween, and enables dimensional stability. Can be ensured. In addition, when applied to a circuit board or the like that transmits a high-frequency signal of 10 GHz or more, transmission loss can be reduced. Therefore, reliability and yield can be improved in the circuit board.

It is a mimetic diagram showing composition of a metal clad laminate of one embodiment of the present invention. It is a typical sectional view showing the composition of the metal clad laminate of a preferred embodiment of the present invention.

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

[Metal-clad laminate]
FIG. 1 is a schematic diagram illustrating a configuration of a metal-clad laminate according to an embodiment of the present invention. The metal-clad laminate (C) of the present embodiment has a structure in which a pair of single-sided metal-clad laminates are bonded together with 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 a first single-sided metal-clad laminate (C1). An adhesive layer (B) is provided between the second single-sided metal-clad laminates (C2). Here, the first single-sided metal-clad laminate (C1) includes a first metal layer (M1) and a first insulating resin layer laminated on at least one surface of the first metal layer (M1). (P1). The second one-sided metal-clad laminate (C2) includes a second metal layer (M2) and a second insulating resin layer (P2) laminated on at least one surface of the second metal layer (M2). And Then, the adhesive layer (B) is disposed so as to contact the first insulating resin layer (P1) and the second insulating resin layer (P2). That is, the metal-clad laminate (C) is composed of the first metal layer (M1) / first insulating resin layer (P1) / adhesive layer (B) / second insulating resin layer (P2) / second metal It has a structure in which the layer (M2) is stacked in this order. The first metal layer (M1) and the second metal layer (M2) are located on the outermost sides, respectively, and a first insulating resin layer (P1) and a second insulating resin layer (P2) are provided inside the outermost layers. An adhesive layer (B) is interposed 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, a general FPC material can be used, and a commercially available copper-clad laminate or the like may be used. The configuration of the first single-sided metal-clad laminate (C1) and the configuration of the second single-sided metal-clad laminate (C2) may be the same or different.

(Metal layer)
The materials of the first metal layer (M1) and the second metal layer (M2) are not particularly limited, and for example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, Examples include tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof. Among them, copper or a 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 the first metal layer (M1) and the second metal layer (M2).

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

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

(Insulating resin layer)
The first insulating resin layer (P1) and the second insulating resin layer (P2) are not particularly limited as long as they are made of an electrically insulating resin. For example, polyimide, epoxy resin, phenol resin , Polyethylene, polypropylene, polytetrafluoroethylene, silicone, ETFE, etc., and are preferably made of polyimide. Further, the first insulating resin layer (P1) and the second insulating resin layer (P2) are not limited to a single layer, and may be a laminate of a plurality of resin layers. In the present invention, when referred to as polyimide, in addition to polyimide, polyamide imide, polyether imide, polyester imide,
It means a resin made of a polymer having an imide group in its molecular structure, such as polysiloxane imide and polybenzimidazole imide.

<Adhesive layer>
The adhesive layer (B) is made of a thermoplastic resin or a thermosetting resin, and has (i) a storage elastic modulus at 50 ° C. of 1800 MPa or less, and (ii) a maximum storage elastic modulus from 180 ° C. to 260 ° C. And (iii) a glass transition temperature (Tg) of 180 ° C. or less. Examples of such a resin include a polyimide resin, a polyamide resin, an epoxy resin, a phenoxy resin, an acrylic resin, a polyurethane resin, a styrene resin, a polyester resin, a phenol resin, a polysulfone resin, a polyethersulfone resin, a polyphenylene sulfide resin, a polyethylene resin, Polypropylene resin, silicone resin, polyether ketone resin, polyvinyl alcohol resin, polyvinyl butyral resin, styrene-maleimide copolymer, maleimide-vinyl compound copolymer, or (meth) acrylic copolymer, epoxy resin, benzoxazine resin, Resins such as bismaleimide resin and cyanate ester resin, and the like, from which those satisfying the conditions (i) to (iii) are selected or designed to satisfy the conditions (i) to (iii) I And can be used for the adhesive layer (B).

  When the adhesive layer (B) is a thermosetting resin, it may contain an organic peroxide, a curing agent, a curing accelerator, and the like, and if necessary, a curing agent and a curing accelerator, or a catalyst and a cocatalyst. May be used in combination. The amount of the curing agent, the curing accelerator, the catalyst, the cocatalyst, and the addition amount of the organic peroxide and the presence or absence of the addition may be determined as long as the above conditions (i) to (iii) can be secured.

<Layer thickness>
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 of the metal-clad laminate (C) is 70 to 70%. It is within a range of 500 μm, and preferably within a range of 100 to 300 μm. If the total thickness T1 is less than 70 μm, the effect of lowering the transmission loss when forming a circuit board will be insufficient, and if it exceeds 500 μm, the productivity may be reduced.

  Further, the thickness T2 of the adhesive layer (B) is, for example, preferably in the range of 50 to 450 μm, and more preferably in the range of 50 to 250 μm. If the thickness T2 of the adhesive layer (B) is less than the above lower limit, the transmission loss as a high-frequency substrate may increase. On the other hand, when the thickness of the adhesive layer (B) exceeds the above upper limit, problems such as a decrease in dimensional stability may occur.

  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, and may be in the range of 0.5 to 0.7. preferable. If the ratio (T2 / T1) is less than 0.5, it becomes difficult to make T1 70 μm or more, and if it exceeds 0.8, problems such as a decrease in dimensional stability occur.

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

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

The adhesive layer (B) has high thermal expansion but low elasticity and a low glass transition temperature, so that even if the CTE exceeds 30 ppm / K, internal stress generated during lamination can be reduced.
The total thermal expansion coefficient (CTE) of the first insulating resin layer (P1), the adhesive layer (B), and the second insulating resin layer (P2) is preferably 10 ppm / K or more, and more preferably 10 ppm / K. The range is from 30 ppm / K to 30 ppm / K, and more preferably from 15 ppm / K to 25 ppm / K. If the CTE of these resin layers as a whole is less than 10 ppm / K or more than 30 ppm / K, warpage occurs or dimensional stability decreases.

<Glass transition temperature (Tg)>
The adhesive layer (B) has a glass transition temperature (Tg) of 180 ° C. or lower, and preferably 160 ° C. or lower. By setting the glass transition temperature of the adhesive layer (B) to 180 ° C. or lower, thermocompression bonding can be performed at a low temperature, so that internal stress generated at the time of lamination can be relaxed and dimensional change after circuit processing can be suppressed. If the Tg of the adhesive layer (B) exceeds 180 ° C., the temperature at the time of bonding between the first insulating resin layer (P1) and the second insulating resin layer (P2) increases, and the circuit The dimensional stability after processing may be impaired.

<Storage modulus>
The adhesive layer (B) has a storage modulus at 50 ° C. of 1800 MPa or less, and a maximum value of the storage modulus in a temperature range of 180 ° C. to 260 ° C. of 800 MPa or less. Such characteristics of the adhesive layer (B) are considered to be factors that reduce internal stress during thermocompression bonding and maintain dimensional stability after circuit processing. Further, the adhesive layer (B) preferably has a storage elastic modulus at an upper limit temperature (260 ° C.) of the temperature range of 800 MPa or less, and more preferably 500 MPa or less. With such a storage elastic modulus, warping hardly occurs even after passing through a solder reflow step after circuit processing.

<Dielectric loss tangent>
For example, when applied to a circuit board, the first insulating resin layer (P1) and the second insulating resin layer (P2) preferably have a dielectric loss tangent (Tan δ) at 10 GHz in order to suppress deterioration of dielectric loss. Is preferably 0.02 or less, more preferably 0.0005 or more and 0.01 or less, and further preferably 0.001 or more and 0.008 or less. If the dielectric loss tangent at 10 GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds 0.02, when applied to a circuit board, an electric signal of a high-frequency signal is transmitted on a transmission path of a high-frequency signal. Problems such as loss are likely to occur. On the other hand, although the lower limit of the dielectric loss tangent of the first insulating resin layer (P1) and the second insulating resin layer (P2) at 10 GHz is not particularly limited, control of the physical properties of the circuit board as the insulating resin layer is taken into consideration. .

  For example, when applied to a circuit board, the adhesive layer (B) has a dielectric loss tangent (Tan δ) at 10 GHz of preferably 0.015 or less, more preferably 0.01 or less, in order to suppress deterioration of dielectric loss. It is more preferably 0.006 or less. If the dielectric loss tangent at 10 GHz of the adhesive layer (B) exceeds 0.015, when applied to a circuit board, inconveniences such as loss of electric signals on a high-frequency signal transmission path are likely to occur. On the other hand, the lower limit of the dielectric loss tangent of the adhesive layer (B) at 10 GHz is not particularly limited.

<Dielectric constant>
When the first insulating resin layer (P1) and the second insulating resin layer (P2) are applied as, for example, an insulating resin layer of a circuit board, the first insulating resin layer (P1) and the second insulating resin layer (P2) are 10 GHz as a whole in order to ensure impedance matching. Is preferably 4.0 or less. When the dielectric constant at 10 GHz of the first insulating resin layer (P1) and the second insulating resin layer (P2) exceeds 4.0, when applied to a circuit board, the first insulating resin layer (P1) This leads to deterioration of the dielectric loss of the second insulating resin layer (P2), which tends to cause inconvenience such as loss of an electric signal on a high-frequency signal transmission path.

  For example, when applied to a circuit board, the adhesive layer (B) preferably has a dielectric constant of 10 GHz or less at 10 GHz in order to ensure impedance matching. If the dielectric constant of the adhesive layer (B) at 10 GHz exceeds 4.0, when applied to a circuit board, the dielectric loss of the adhesive layer (B) becomes worse, and the loss of an electric signal on the transmission path of a high-frequency signal is reduced. Inconveniences such as are likely to occur.

<Action>
In the metal-clad laminate (C) of the present embodiment, the thickness itself of the adhesive layer (B) is increased in order to reduce the dielectric loss tangent of the entire insulating resin layer and enable high-frequency transmission. . However, since a material having a low elastic modulus such as the adhesive layer (B) generally has a high coefficient of thermal expansion, increasing the layer thickness may cause a decrease in dimensional stability. Here, the dimensional change that occurs when the metal-clad laminate (C) is subjected to circuit processing is mainly caused by the following mechanisms a) to c), and the total amount of b) and c) is It is thought that it appears as a change in dimensional method.
a) When manufacturing the metal-clad laminate (C), internal stress is accumulated in the resin layer.
b) By etching the metal layer during circuit processing, the internal stress accumulated in a) is released, and the resin layer expands or contracts.
c) During the circuit processing, the exposed resin absorbs moisture and expands by etching the metal layer.

  The factors of the internal stress in the above a) are a) a difference in thermal expansion coefficient between the metal layer and the resin layer, and b) a resin internal strain caused by film formation. Here, the magnitude of the internal stress due to a) affects not only the difference in thermal expansion coefficient but also the temperature difference ΔT from the temperature at the time of bonding (heating temperature) to the temperature of cooling and solidification. That is, since the internal stress increases in proportion to the temperature difference ΔT, even if the difference in the coefficient of thermal expansion between the metal layer and the resin layer is small, the internal stress increases as the resin requires a high temperature for bonding. . In the metal-clad laminate (C) of the present embodiment, by using a material that satisfies the above conditions (i) to (iii) as the adhesive layer (B), the internal stress is reduced to secure dimensional stability. doing.

  Further, since the adhesive layer (B) is laminated between the first insulating resin layer (P1) and the second insulating resin layer (P2), it functions as an intermediate layer, and has warpage and dimensional change. Suppress. Further, in a heating step such as solder reflow at the time of mounting a semiconductor chip, for example, the first insulating resin layer (P1) or the second insulating resin layer (P2) blocks direct contact with heat or oxygen. Therefore, it is hardly affected by the oxidative deterioration and the dimensional change hardly occurs. As described above, there is also an advantage due to the features of the layer structure of the first insulating resin layer (P1), the adhesive layer (B), and the second insulating resin layer (P2).

[Manufacture of metal-clad laminates]
The metal-clad laminate (C) can be manufactured, for example, by the following method 1 or method 2.
[Method 1]
The resin composition to be the adhesive layer (B) is formed into a sheet to form an adhesive sheet, and the adhesive sheet is formed from a first insulating resin layer (P1) of a first single-sided metal-clad laminate (C1); A method of arranging and bonding between the second insulating resin layer (P2) of the second single-sided metal-clad laminate (C2) and thermocompression bonding.
[Method 2]
The solution of the resin composition to be the adhesive layer (B) is applied to the first insulating resin layer (P1) of the first single-sided metal-clad laminate (C1) or the second insulating resin layer (C2) of the single-sided metal-clad laminate (C2). A method of applying and drying a predetermined thickness to one or both of the insulating resin layers (P2) of No. 2 and bonding the coated film side and thermocompression bonding.

The adhesive sheet used in the method 1 can be manufactured, for example, by a method in which a solution of the resin composition to be the adhesive layer (B) is applied to an arbitrary supporting substrate, dried, and then peeled off from the supporting substrate to form an adhesive sheet. .
Further, in the above, the method of applying the solution of the resin composition to be the adhesive layer (B) on the supporting base material and the insulating resin layers (P1, P2) is not particularly limited, and examples thereof include commas, dies, knives, and the like. It can be applied with a coater such as a lip.

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

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

  FIG. 2 is a schematic sectional view showing the structure of the metal-clad laminate 100 of 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), a first insulating resin layer (P1), It has polyimide layers 110 and 110 as 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 a first single-sided metal-clad laminate (C1) or a second single-sided metal-clad laminate (C2). In this embodiment, the configurations of the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) are the same.

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

  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. doing. The adhesive polyimide layer 120 is an adhesive layer for bonding the two single-sided metal-clad laminates 130, 130 in the metal-clad laminate 100, and secures the dimensional stability of the metal-clad laminate 100. This is for increasing the thickness of the insulating resin layer. 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, 110 will be described. In addition, “non-thermoplastic polyimide” generally refers to a polyimide that does not soften or exhibit adhesion even when heated, but in the present invention, it is measured using a dynamic viscoelasticity measuring device (DMA). It refers to a polyimide having a storage elastic modulus at 1.0 ° C. of 1.0 × 10 ⁹ Pa or more and a storage elastic modulus at 350 ° C. of 1.0 × 10 ⁸ Pa or more. The term “thermoplastic polyimide” generally refers to a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, the storage elastic modulus at 30 ° C. measured using DMA is 1.0%. X 10 ⁹ Pa or more, and refers to a polyimide having a storage elastic modulus at 350 ° C of less than 1.0 x 10 ⁸ 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. It represents that. 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 has 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 1,4-phenylenebis (tetracarboxylic acid residue) as tetracarboxylic acid residues. A tetracarboxylic acid residue derived from at least one of trimellitic acid monoester) dianhydride (TAHQ) and pyromellitic dianhydride (PMDA) and 2,3,6,7-naphthalenetetracarboxylic dianhydride It preferably contains a tetracarboxylic acid residue derived from at least one product (NTCDA).

  The tetracarboxylic acid residue derived from BPDA (hereinafter, also referred to as “BPDA residue”) and the tetracarboxylic acid residue derived from TAHQ (hereinafter, also referred to as “TAHQ residue”) are ordered in the polymer. The structure can be easily formed, and the dielectric loss tangent and the hygroscopicity can be reduced by suppressing the movement of molecules. The BPDA residue can provide the self-supporting property of the gel film as a polyamic acid of the polyimide precursor, while increasing the CTE after imidation and lowering the glass transition temperature to lower the heat resistance. Become a trend.

  From such a viewpoint, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 preferably has a total of 30 mol parts of BPDA residues and TAHQ residues with respect to 100 mol parts of all tetracarboxylic acid residues. The content is controlled so as to be in the range of not less than 60 mole parts and more preferably in the range of not less than 40 mole parts and not more than 50 mole parts. When the total of the BPDA residue and the TAHQ residue is less than 30 mol parts, the formation of an ordered structure of the polymer becomes insufficient, the moisture absorption resistance is reduced, and the dielectric loss tangent is insufficiently reduced. If it exceeds, the CTE may increase, the amount of change in in-plane retardation (RO) may increase, and the heat resistance may decrease.

Further, tetracarboxylic acid residues derived from pyromellitic dianhydride (hereinafter also referred to as “PMDA residues”) and tetracarboxylic acid residues derived from 2,3,6,7-naphthalenetetracarboxylic dianhydride Carboxylic acid residues (hereinafter also referred to as “NTCDA residues”) have rigidity, so that in-plane orientation is increased, CTE is suppressed, and in-plane retardation (RO) is controlled and glass transition temperature is reduced. Is a residue that plays a role in the regulation of On the other hand, since the molecular weight of the PMDA residue is small, if the amount is too large, the imide group concentration of the polymer will increase, the polar group will increase, and the hygroscopicity will increase. The effect increases the dielectric loss tangent. The NTCDA residue tends to make the film brittle due to the naphthalene skeleton having high rigidity, and tends to increase the elastic modulus.
Therefore, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer, the total of the PMDA residue and NTCDA residue is preferably 40 mol parts or more and 70 mol parts or less with respect to 100 mol parts of all the tetracarboxylic acid residues. , More preferably in the range of 50 to 60 parts by mole, and even more preferably in the range of 50 to 55 parts by mole. If the total of the PMDA residue and the NTCDA residue is less than 40 mol parts, the CTE may increase or the heat resistance may decrease. If the total exceeds 70 mol parts, the imide group concentration of the polymer increases, and the polarity increases. The group may be increased to impair the low hygroscopicity and increase the dielectric loss tangent, or the film may become brittle and the self-supporting property of the film may be reduced.

  In addition, the total of at least one kind of BPDA residue and TAHQ residue and at least one kind of PMDA residue and NTCDA residue is 80 mol parts or more, preferably 90 mol parts to 100 mol parts of all tetracarboxylic acid residues. It is preferable that the amount be at least a molar part.

  In addition, the molar ratio of at least one of BPDA residues and TAHQ residues to at least one of PMDA residues and NTCDA residues {(BPDA residue + TAHQ residue) / (PMDA residue + NTCDA residue)} is set to 0.1. The range of 4 to 1.5, preferably 0.6 to 1.3, more preferably 0.8 to 1.2 to control the formation of an ordered structure of CTE and polymer It is better to do.

  Since PMDA and NTCDA have a rigid skeleton, the in-plane orientation of molecules in polyimide can be controlled as compared with other general acid anhydride components, and the coefficient of thermal expansion (CTE) can be suppressed and glass can be suppressed. There is an effect of improving the transition temperature (Tg). Further, since BPDA and TAHQ have a higher molecular weight than PMDA, the imide group concentration is reduced by increasing the charge ratio, which is effective in reducing the dielectric loss tangent and the moisture absorption rate. On the other hand, when the charge ratio of BPDA and TAHQ increases, the in-plane orientation of molecules in the polyimide decreases, leading to an increase in CTE. Further, the formation of an ordered structure in the molecule proceeds, and the haze value increases. From such a viewpoint, the total charged amount of PMDA and NTCDA is in the range of 40 to 70 mol parts, preferably in the range of 50 to 60 mol parts, relative to 100 mol parts of the total acid anhydride component of the raw material. More preferably, the amount is in the range of 50 to 55 mol parts. If the total charged amount of PMDA and NTCDA is less than 40 mol parts with respect to 100 mol parts of the total acid anhydride component of the raw material, the in-plane orientation of the molecule is reduced, making it difficult to reduce the CTE, and The heat resistance and dimensional stability of the film at the time of heating due to a decrease in the temperature decrease. On the other hand, when the total amount of PMDA and NTCDA exceeds 70 mol parts, the moisture absorption rate tends to deteriorate due to an increase in the imide group concentration, and the elastic modulus tends to increase.

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

  The BPDA residue, the TAHQ residue, the PMDA residue, and the tetracarboxylic acid residue other than the NTCDA residue included in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 include, for example, 3,3 ′, 4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3 '-, 2,3,3', 4'- or 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,3', 3,4'-diphenylethertetracarboxylic dianhydride, Bis (2,3-dicarboxyphenyl) ether dianhydride, 3,3 ″, 4,4 ″-, 2,3,3 ″, 4 ″-or 2,2 ″, 3,3 '' -p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4 -Dicarboxyphenyl) methane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane Dianhydride, 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic Acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6 -Tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4, , 8-) Tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10 -, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2, 3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4 Examples include tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydrides such as' -bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride and ethylene glycol bisanhydrotrimellitate.

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

In the formula (1), the linking group Z represents a single bond or —COO—, and Y independently represents a monovalent hydrocarbon having 1 to 3 carbon atoms which may be substituted with a halogen atom or a phenyl group, or Represents an alkoxy group having 1 to 3 or 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, in the above formula (1), the plurality of substituents Y and the integers p and q may be the same or different. In the above formula (1), the hydrogen atoms in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ independently represent an alkyl group or the like. (Meaning any substituent).

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

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

  The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 has a diamine residue derived from diamine (1), preferably at least 80 mol parts, more preferably at least 80 mol parts, based on 100 mol parts of all diamine residues. It is preferable to contain 85 mol parts or more. By using the diamine (1) in an amount within the above range, an ordered structure is easily formed in the entire polymer due to the rigid structure derived from the monomer, the gas permeability is low, the moisture absorption is low, and the dielectric loss tangent is low. A non-thermoplastic polyimide is easily obtained.

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

  Other diamine residues contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 include, for example, 2,2-bis- [4- (3-aminophenoxy) phenyl] propane and bis [4- ( 3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) phenyl] methane, bis [ 4- (3-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [ 4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4'- Tylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3′-dimethoxybenzidine, 3,3 ″ -diamino-p-terphenyl, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4 ′-[1, 3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) Benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2, 4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xy Diamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4,4 ' -Diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, etc. A diamine residue derived from an aromatic diamine compound, derived from an aliphatic diamine compound such as a dimer acid type diamine in which two terminal carboxylic acid groups of dimer acid are substituted with a primary aminomethyl group or an amino group. Diamine residue.

  In the non-thermoplastic polyimide, by selecting the type of the tetracarboxylic acid residue and the diamine residue and the respective molar ratio when applying two or more kinds of tetracarboxylic acid residues or diamine residues, thermal expansion The modulus, storage modulus, tensile modulus and the like can be controlled. When the non-thermoplastic polyimide has a plurality of polyimide structural units, it may be present as a block or may be present at random, but from the viewpoint of suppressing variation in in-plane retardation (RO), Is preferably present.

  In addition, the tetracarboxylic acid residue and the diamine residue contained in the non-thermoplastic polyimide are both made to be aromatic groups, so that the dimensional accuracy of the polyimide film in a high-temperature environment is improved, and in-plane retardation (RO) This is preferable because the amount of change in can be reduced.

The imide group concentration of the non-thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide group (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33%, the molecular weight of the resin itself decreases, and the low hygroscopicity also deteriorates due to an increase in the number of polar groups. By controlling the orientation of the molecules in the non-thermoplastic polyimide by selecting the combination of the acid anhydride and the diamine compound, it is possible to suppress an increase in CTE due to a decrease in the imide group concentration and to ensure low hygroscopicity. ing.

  The weight average molecular weight of the non-thermoplastic polyimide is, for example, preferably in the range of 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. If the weight average molecular weight is less than 10,000, the strength of the film tends to decrease and the film tends to become brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased and defects such as unevenness in 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 or more and 100 μm or less, from the viewpoint of ensuring the function as a base layer, and from the viewpoint of transportability during manufacturing and thermoplastic polyimide coating, and is preferably 9 μm. More preferably, it is in the range of not less than 50 μm. When the thickness of the non-thermoplastic polyimide layer 111 is less than the above lower limit, the electrical insulation and handling properties become insufficient, and when the thickness exceeds the upper limit, productivity decreases.

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

  From the viewpoint of suppressing warpage, the coefficient of thermal expansion of the non-thermoplastic polyimide layer 111 is in the range of 1 pm / K to 30 ppm / K, preferably in the range of 1 ppm / K to 25 ppm / K, more preferably It is preferable that the concentration be in the range of 15 ppm / K or more and 25 ppm / K or less.

  The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 111 has, as optional components, for example, a plasticizer, another cured resin component such as an epoxy resin, a curing agent, a curing accelerator, a coupling agent, a filler, A solvent, a flame retardant and the like can be appropriately compounded. However, some plasticizers contain a large amount of polar groups, which may promote the diffusion of copper from the copper wiring. Therefore, it is preferable that the plasticizer is not used as much as possible.

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

(Tetracarboxylic acid residue)
As the tetracarboxylic acid residue used for the thermoplastic polyimide constituting the thermoplastic polyimide layer 112, the same one as exemplified as the tetracarboxylic acid residue in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is used. be able to.

(Diamine residue)
As the diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112, a diamine residue derived from a diamine compound represented by any of the general formulas (B1) to (B7) is preferable.

In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, and the linking group A independently represents -O-, -S-, -CO-. _{, -SO -, - SO 2 -} , - COO -, - CH 2 -, - C (CH 3) 2 -, - NH- or a divalent group selected from -CONH-, _{n 1} is independently Shows an integer of 0 to 4. However, those overlapping formula (B2) are excluded from formula (B3), and those overlapping formula (B4) from formula (B5) are excluded. Here, “independently” means that in one or two or more of the above formulas (B1) to (B7), a plurality of linking groups A, a plurality of R _1, or a plurality of n ₁ are the same. Or may be different. In the above formulas (B1) to (B7), the hydrogen atoms in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ are independently Any 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. This diamine (B1) has a high flexibility by increasing the degree of freedom of the polyimide molecular chain because the amino group directly bonded to at least one benzene ring and the divalent linking group A are at the meta position. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of the diamine (B1) increases the thermoplasticity of the polyimide. Here, the linking group _{A, -O -, - CH 2} -, - C (CH 3) 2 -, - CO -, - SO 2 -, - S- are preferred.

  Examples of the diamine (B1) include 3,3′-diaminodiphenylmethane, 3,3′-diaminodiphenylpropane, 3,3′-diaminodiphenylsulfide, 3,3′-diaminodiphenylsulfone, and 3,3′-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, (3,3'- (Bisamino) 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) has a high flexibility by increasing the degree of freedom of the polyimide molecular chain because the amino group directly bonded to at least one benzene ring and the divalent linking group A are at the meta position. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the thermoplasticity of the polyimide is increased by using the diamine (B2). Here, the connecting group A is preferably -O-.

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

  The diamine represented by the formula (B3) (hereinafter sometimes referred to as “diamine (B3)”) is an aromatic diamine having three benzene rings. This diamine (B3) has high flexibility by increasing the degree of freedom of the polyimide molecular chain because the two divalent linking groups A directly bonded to one benzene ring are at the meta position with each other. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of the diamine (B3) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

  Examples of the diamine (B3) include 1,3-bis (4-aminophenoxy) benzene (TPE-R), 1,3-bis (3-aminophenoxy) benzene (APB), and 4,4 ′-[2- Methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4 '-[4-methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4'-[5-methyl- (1,3-phenylene ) Bisoxy] bisaniline 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. This diamine (B4) has high flexibility by having at least one amino group directly bonded to the benzene ring and the divalent linking group A at the meta position, and is useful for improving the flexibility of the polyimide molecular chain. It is thought to contribute. Therefore, the thermoplasticity of the polyimide is increased by using the diamine (B4). Here, the linking group _{A, -O -, - CH 2} -, - C (CH 3) 2 -, - SO 2 -, - CO -, - CONH- are preferred.

  Examples of the diamine (B4) include bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] ether, [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 ′-(3-aminophenoxy)] benzanilide and the like can be mentioned.

  The diamine represented by the formula (B5) (hereinafter sometimes referred to as “diamine (B5)”) is an aromatic diamine having four benzene rings. This diamine (B5) has high flexibility by increasing the degree of freedom of the polyimide molecular chain by having two divalent linking groups A directly bonded to at least one benzene ring at the meta position. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (B5) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

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

The diamine represented by the formula (B6) (hereinafter sometimes referred to as “diamine (B6)”) is an aromatic diamine having four benzene rings. This diamine (B6) has high flexibility by having at least two ether bonds, and is considered to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, the use of the diamine (B6) increases the thermoplasticity of the polyimide. Here, as the connecting group A, —C (CH ₃ ) ₂ —, —O—, —SO ₂ —, and —CO— are preferable.

  Examples of the diamine (B6) include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), bis [4 -(4-aminophenoxy) phenyl] sulfone (BAPS), 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. Since this diamine (B7) has a highly flexible divalent linking group A on both sides of the diphenyl skeleton, it is considered that the diamine (B7) contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of the diamine (B7) increases the thermoplasticity of the polyimide. Here, the connecting 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 has a diamine residue derived from at least one diamine compound selected from diamines (B1) to diamines (B7) with respect to 100 mol parts of all diamine residues. It may be contained in an amount of 60 mol parts or more, preferably 60 mol parts or more and 99 mol parts or less, more preferably 70 mol parts or more and 95 mol parts or less. Since the diamines (B1) to (B7) have a flexible molecular structure, the flexibility of the polyimide molecular chain is improved by using at least one diamine compound selected from these in an amount within the above range. To impart thermoplasticity. If the total amount of the diamine (B1) to diamine (B7) in the raw material is less than 60 mol parts with respect to 100 mol parts of all diamine components, sufficient thermoplasticity cannot be obtained due to insufficient flexibility of the polyimide resin.

  Further, as the diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 112, a diamine residue derived from a diamine compound represented by the general formula (1) is also preferable. The diamine compound [diamine (1)] represented by the formula (1) is as described in the description of the non-thermoplastic polyimide. Diamine (1) has a rigid structure and an action of imparting an ordered structure to the entire polymer, so that the dielectric loss tangent and hygroscopicity can be reduced by suppressing the movement of molecules. Further, by using as a raw material of a thermoplastic polyimide, a polyimide having low gas permeability and excellent long-term heat resistance can be obtained.

  The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 contains a diamine residue derived from the diamine (1) in a range of preferably 1 to 40 mol parts, more preferably 5 to 30 mol parts. It may be contained within the following range. By using the diamine (1) in an amount within the above range, an ordered structure is formed throughout the polymer due to the rigid structure derived from the monomer. Therefore, while being thermoplastic, gas permeability and hygroscopicity are low, and A polyimide excellent in heat resistance can be obtained.

  The thermoplastic polyimide constituting the thermoplastic polyimide layer 112 can include a diamine residue derived from a diamine compound other than the diamines (1) and (B1) to (B7) as long as the effects of the invention are not impaired. .

  In the thermoplastic polyimide, the coefficient of thermal expansion is selected by selecting the type of the tetracarboxylic acid residue and the diamine residue and the respective molar ratio when two or more tetracarboxylic acid residues or diamine residues are applied. , Tensile modulus, glass transition temperature, etc. can be controlled. When the thermoplastic polyimide has a plurality of polyimide structural units, it may be present as a block or may be present at random, but is preferably present at random.

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

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

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

Since the thermoplastic polyimide constituting the thermoplastic polyimide layer 112 becomes, for example, an adhesive layer in an insulating resin of a circuit board, a completely imidized structure is most preferable to suppress the diffusion of copper. However, a part of the polyimide may be an amic acid. The imidation ratio was measured at about 1015 cm ^-1 by measuring the infrared absorption spectrum of a polyimide thin film by a single reflection ATR method using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). Is calculated from the absorbance of C = O stretching derived from the imide group at 1780 cm ^-1 based on the benzene ring absorber of the formula ( ¹ ).

  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 1 μm or more and 5 μm or less, from the viewpoint of securing the adhesive function. When the thickness of the thermoplastic polyimide layer 112 is less than the above lower limit, the adhesiveness becomes insufficient, and when it exceeds the upper limit, the dimensional stability tends to deteriorate.

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

  In addition, in the resin used for the thermoplastic polyimide layer 112, in addition to polyimide, as an optional component, for example, a plasticizer, another cured resin component such as an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a coupling agent, Fillers, solvents, flame retardants and the like can be appropriately compounded. However, some plasticizers contain a large amount of polar groups, which may promote the diffusion of copper from the copper wiring. Therefore, it is preferable that the plasticizer is not used as much as possible.

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

(Synthesis of polyimide)
The polyimide constituting the polyimide layer 110 can be produced by reacting the above-mentioned acid anhydride and diamine in a solvent to form a precursor resin, and then heat-closing the precursor resin. For example, a polyimide precursor is obtained by dissolving an acid anhydride component and a diamine component in an organic solvent in approximately equimolar amounts and stirring at a temperature within a range of 0 to 100 ° C. for 30 minutes to 24 hours to cause a polymerization reaction. A polyamic acid is obtained. In the reaction, the reaction components are dissolved so that the generated precursor is in the range of 5 to 30% by weight, preferably 10 to 20% by weight in the organic solvent. Examples of the organic solvent used for the polymerization reaction include N, N-dimethylformamide, N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone, 2-butanone, dimethylsulfoxide, dimethyl sulfate, cyclohexanone, and dioxane. , Tetrahydrofuran, diglyme, triglyme and the like. Two or more of these solvents can be used in combination, and further, an aromatic hydrocarbon such as xylene or toluene can be used in combination. The use amount of such an organic solvent is not particularly limited, but may be such that the concentration of the polyamic acid solution (polyimide precursor solution) obtained by the polymerization reaction is about 5 to 30% by weight. It is preferable to use it after adjusting.

  In the synthesis of polyimide, each of the above-mentioned acid anhydrides and diamines may be used alone or in combination of two or more. By selecting the types of the acid anhydride and the diamine and the respective molar ratios when using two or more acid anhydrides or diamines, it is possible to control the thermal expansion property, the adhesive property, the glass transition temperature, and the like. .

  Usually, the synthesized precursor is advantageously used as a reaction solvent solution, but can be concentrated, diluted, or replaced with another organic solvent if necessary. Further, the precursor is generally used because it is excellent in solvent solubility. The method of imidizing the precursor is not particularly limited. For example, a heat treatment in which the precursor is heated in the solvent under a temperature condition of 80 to 400 ° C. for 1 to 24 hours is suitably employed.

[Circuit board]
The metal-clad laminate 100 is mainly useful as a circuit board material such as an FPC and a rigid / flex circuit board. That is, by processing one or both of the two metal layers 101 of the metal-clad laminate 100 into a pattern by a conventional method to form a wiring layer, a circuit board such as an FPC according to an embodiment of the present invention is formed. 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.

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

[Measurement of dielectric constant and dissipation factor]
The dielectric constant (Dk) and the dielectric loss tangent (Df) of the polyimide film at 10 GHz were measured using a vector network analyzer (manufactured by Agilent, trade name: E8363C) and an SPDR resonator. The materials used for the measurement were left for 24 hours under the conditions of a temperature of 24 to 26 ° C. and a humidity of 45 ° C. to 55% RH.

[Measurement of storage modulus and glass transition temperature (Tg)]
The storage elastic modulus of the adhesive layer was determined by peeling and removing the adhesive layer (thickness: 50 m) from the base material film, cutting it into 5 mm × 20 mm, and heating it in a 120 ° C. oven for 2 hours and 170 ° C. for 3 hours. The obtained sample was heated stepwise from 30 ° C to 400 ° C at a heating rate of 4 ° C / min using a dynamic viscoelasticity device (DMA: trade name; E4000F, manufactured by UBM Corporation), The measurement was performed at a frequency of 11 Hz. Further, the maximum temperature at which the value of Tan δ during measurement was maximum was defined as Tg.

[Measurement of dimensional change rate]
The measurement of the dimensional change rate was performed in the following procedure. First, a target for position measurement is formed by exposing and developing a dry film resist at intervals of 100 mm using a 150 mm square test piece. After measuring dimensions before etching (normal state) in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, copper other than the target of the test piece is etched (liquid temperature 40 ° C. or less, time 10 minutes or less). To remove. After standing in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5% for 24 ± 4 hours, the dimensions after etching are measured. The dimensional change rate with respect to the normal state at each of the three locations in the MD direction (longitudinal direction) and the TD direction (width direction) is calculated, and the average value of each is defined as the dimensional change rate after etching. The dimensional change after etching was calculated by the following equation.

Dimensional change after etching (%) = (BA) / A × 100
A: distance between targets before etching B: distance between targets after etching

  Next, this test piece is heat-treated in an oven at 250 ° C. for 1 hour, and then the distance between the position targets is measured. The dimensional change rates after etching at three locations in each of the MD direction (longitudinal direction) and the TD direction (width direction) are calculated, and the average value of each is defined as the dimensional change rate after heat treatment. The heating dimensional change rate was calculated by the following equation.

Dimensional change after heating (%) = (CB) / B × 100
B: distance between targets after etching C: distance between targets after heating

The abbreviations used in this example indicate the following compounds.
BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride PMDA: pyromellitic dianhydride BTDA: 3,3', 4,4'-benzophenonetetracarboxylic dianhydride m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-bis (4-aminophenoxy) benzenebisaniline-M: 1,3-bis [2- (4-aminophenyl)- 2-propyl] benzene DDA: manufactured by Croda Japan Co., Ltd. (trade name: PRIAMINE 1075)
N-12: dodecane diacid dihydrazide DMAc: N, N-dimethylacetamide R710: (trade name, manufactured by Printec Co., Ltd., bisphenol type epoxy resin, epoxy equivalent: 170, liquid at ordinary temperature, weight average molecular weight: about 340)
VG3101L: (trade name, manufactured by Printec Co., Ltd., polyfunctional epoxy resin, epoxy equivalent: 210, softening point: 39 to 46 ° C.)
SR35K: (trade name, manufactured by PRINTECH, epoxy resin, epoxy equivalent: 930-940, softening point: 86-98 ° C)
YDCN-700-10: (trade name, Nippon Steel & Sumikin Chemical Co., Ltd., cresol novolak type epoxy resin, epoxy equivalent 210, softening point 75-85 ° C)
Millex XLC-LL: (trade name, manufactured by Mitsui Chemicals, Inc., phenolic resin, hydroxyl equivalent: 175, softening point: 77 ° C, water absorption: 1% by mass, heating mass decrease: 4% by mass)
HE200C-10: (trade name, manufactured by Air Water Co., Ltd., phenolic resin, hydroxyl equivalent: 200, softening point: 65 to 76 ° C., water absorption: 1% by mass, heating mass reduction: 4% by mass)
HE910-10: (trade name, manufactured by Air Water Co., Ltd., phenolic resin, hydroxyl equivalent: 101, softening point: 83 ° C, water absorption: 1% by mass, heating mass reduction: 3% by mass)
SC1030-HJA: (trade name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size: 0.25 μm)
Aerosil R972: (trade name, manufactured by Nippon Aerosil Co., Ltd., silica, average particle diameter: 0.016 μm)
Acrylic rubber HTR-860P-30B-CHN: (sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight: 230,000, glycidyl functional group monomer ratio: 8%, Tg: -7 ° C)
Acrylic rubber HTR-860P-3CSP: (sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight: 800,000, glycidyl functional group monomer ratio: 3%, Tg: -7 ° C)
A-1160: (trade name, manufactured by GE Toshiba Corporation, γ-ureidopropyltriethoxysilane)
A-189: (trade name, manufactured by GE Toshiba Corporation, γ-mercaptopropyltrimethoxysilane)
Cureazole 2PZ-CN: (trade name, 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Chemical Industry Co., Ltd.)
RE-810NM: (trade name, manufactured by Nippon Kayaku Co., Ltd., diallyl bisphenol A diglycidyl ether, property: liquid)
Foret SCS: (trade name, manufactured by Soken Chemical Co., Ltd., styryl group-containing acrylic polymer, Tg: 70 ° C., weight average molecular weight: 15000)
BMI-1: (trade name, manufactured by Tokyo Chemical Industry Co., Ltd., 4,4'-bismaleimidodiphenylmethane)
TPPK: (trade name, manufactured by Tokyo Chemical Industry Co., Ltd., tetraphenylphosphonium tetraphenylborate)
HP-P1: (trade name, manufactured by Mizushima Alloy Iron Co., Ltd., boron nitride filler)
NMP: (N-methyl-2-pyrrolidone, manufactured by Kanto Chemical Co., Ltd.)

(Synthesis example 1)
<Preparation of resin solution A for adhesive layer>
Cyclohexanone was added to a composition comprising (a) an epoxy resin and a phenolic resin as a thermosetting resin and (c) an inorganic filler having the product name and the composition ratio (unit: parts by mass) shown in Table 1, and stirred and mixed. To this, (b) an acrylic rubber as a high molecular weight component shown in Table 1 was added and stirred, and (e) a coupling agent and (d) a curing accelerator shown in Table 1 were further added to make each component uniform. The mixture was stirred until the solution was obtained to obtain a resin solution A for the adhesive layer.

(Synthesis example 2)
<Synthesis of polyimide resin (PI-1) and preparation of resin solution B for adhesive layer>
1,3-bis (3-aminopropyl) tetramethyldisiloxane (trade name: LP-7100, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 300 mL flask equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen inlet pipe. 15.53 g, 28.13 g of polyoxypropylene diamine (manufactured by BASF Corporation, trade name: D400, molecular weight: 450), and 100.0 g of NMP were charged and stirred to prepare a reaction solution. After the diamine was dissolved, 32.30 g of 4,4'-oxydiphthalic dianhydride, which had been previously purified by recrystallization from acetic anhydride, was added to the reaction solution little by little while cooling the flask in an ice bath. After reacting at room temperature (25 ° C.) for 8 hours, 67.0 g of xylene was added, and the mixture was heated at 180 ° C. while blowing in nitrogen gas to azeotropically remove xylene 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). When the molecular weight of the obtained polyimide resin (PI-1) was measured by GPC, the number average molecular weight Mn was 22,400 and the weight average molecular weight Mw was 70,200 in terms of polystyrene.
Using the polyimide resin (PI-1) obtained above, 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.

(Synthesis example 3)
<Preparation of polyamic acid solution for insulating resin layer>
Under a nitrogen stream, 64.20 g of m-TB (0.302 mol) and 5.48 g of bisaniline-M (0.016 mol) and an amount such that the solid content concentration after polymerization was 15% by weight were added to the reaction vessel. Was added and stirred at room temperature to dissolve. Next, after adding 34.20 g of PMDA (0.157 mol) and 46.13 g of BPDA (0.157 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours, and the polyamic acid solution 1 (viscosity ; 26,500 cps).

(Synthesis example 4)
<Preparation of polyamic acid solution for insulating resin layer>
69.56 g of m-TB (0.328 mol), 542.75 g of TPE-R (1.857 mol), DMAc in an amount to give a solid content concentration of 12% by weight after polymerization, 194.39 g of PMDA ( Polyamic acid solution 2 (viscosity: 2,650 cps) was prepared in the same manner as in Synthesis Example 3 except that the raw material compositions were 0.891 mol) and 393.31 g of BPDA (1.337 mol).

(Production Example 1)
<Preparation of resin sheet A for adhesive layer>
After drying the resin solution A for the adhesive layer on the silicone-treated surface of the release substrate (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness becomes 50 μm after drying, the resin solution A is heated at 80 ° C. for 15 minutes. After drying by heating and further drying at 120 ° C. for 15 minutes, the resin sheet A was prepared by peeling off from the release substrate. The resin sheet A was heated in an oven at 120 ° C. for 2 hours and at 170 ° C. for 3 hours in order to evaluate physical properties after curing. At that time, the cured resin sheet A had a Tg of 95 ° C., a storage elastic modulus at 50 ° C. of 960 MPa, and a maximum storage elastic modulus at 180 ° C. to 260 ° C. of 7 MPa.

(Production Example 2)
<Preparation of resin sheet B for adhesive layer>
After coating the resin solution B for the adhesive layer on the silicone-treated surface of the release substrate (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness becomes 50 μm after drying, the resin solution B is heated at 80 ° C. for 15 minutes. After drying by heating and further drying at 120 ° C. for 15 minutes, the resin sheet B was prepared by peeling off from the release substrate. The resin sheet B was heated in an oven at 120 ° C. for 2 hours and at 170 ° C. for 3 hours in order to evaluate physical properties after curing. At that time, the cured resin sheet B had a Tg of 100 ° C. or less, a storage modulus at 50 ° C. of 1800 MPa or less, and a maximum value of storage modulus at 180 ° C. to 260 ° C. of 70 MPa.

(Production Example 3)
<Preparation of single-sided metal-clad laminate>
The polyamic acid solution 2 is uniformly coated on 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 is about 2 to 3 μm. After the application, it was dried by heating at 120 ° C. to remove the solvent. Next, the polyamic acid solution 1 was uniformly applied thereon so as to have a cured thickness of about 21 μm, and dried by heating at 120 ° C. to remove the solvent. Further, the polyamic acid solution 2 was uniformly applied thereon so as to have a thickness of about 2-3 μm after curing, and then heated and dried at 120 ° C. to remove the solvent. Furthermore, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete the imidization, and a single-sided metal-clad laminate 1 was prepared. The dimensional change rate of the single-sided metal-clad laminate 1 is as follows.
Dimensional change after etching in MD direction (longitudinal direction): 0.01%
Dimensional change after etching in TD direction (width direction); -0.04%
Dimensional change after heating in MD direction (longitudinal direction): -0.03%
Dimensional change after heating in TD direction (width direction): -0.01%

<Preparation of polyimide film>
The copper foil 1 of the single-sided metal-clad laminate 1 is removed by etching using an aqueous ferric chloride solution to obtain a polyimide film 1 (thickness: 25 μm, CTE: 20 ppm / K, Dk: 3.40, Df: 0.0029). Prepared.

[Example 1]
Two single-sided metal-clad laminates 1 are prepared, the respective surfaces on the insulating resin layer side are overlaid on both surfaces of the resin sheet A, and pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa to obtain a metal. Clad laminate 1 was prepared. The evaluation results of the metal-clad laminate 1 are as follows.
Dimensional change after etching in MD direction: -0.02%
Dimensional change after etching in the TD direction: -0.03%
Dimensional change after heating in MD direction: -0.02%
Dimensional change after heating in TD direction: -0.02%
The metal-clad laminate 1 had no warpage and no dimensional change. The CTE of the resin laminate 1 (thickness: 100 μm) prepared by etching the copper foil 1 of the metal-clad laminate 1 was 24.1 ppm / K.

[Example 2]
Two single-sided metal-clad laminates 1 are prepared, their respective surfaces facing the insulating resin layer are superimposed on both surfaces of the resin sheet B, and pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa to form a metal plate. Clad laminate 2 was prepared. The evaluation results of the metal-clad laminate 2 are as follows.
Dimensional change after etching in MD direction: -0.05%
Dimensional change after etching in TD direction: -0.05%
Dimensional change after heating in MD direction: -0.03%
Dimensional change after heating in TD direction: -0.04%
The metal-clad laminate 2 had no warpage and no dimensional change. The CTE of the resin laminate 2 (thickness: 100 μm) prepared by etching the copper foil 1 of the metal-clad laminate 2 was 23.3 ppm / K.

(Comparative Example 1)
2. In place of the resin sheet A, a fluororesin sheet (trade name; manufactured by Asahi Glass Co., Ltd .; trade name; adhesive perfluororesin EA-2000, thickness: 50 μm, Tm: 303 ° C., Tg; none) was used at 320 ° C. for 5 minutes. A metal-clad laminate 3 was prepared in the same manner as in Example 1, except that pressure was applied under a pressure of 5 MPa.
The evaluation results of the metal-clad laminate 3 are as follows.
Dimensional change after etching in MD direction: -0.11%
Dimensional change after etching in TD direction: -0.13%
Dimensional change after heating in MD direction: -0.19%
Dimensional change after heating in TD direction: -0.20%
The metal-clad laminate 3 had no warpage and no dimensional change. The CTE of the resin laminate 3 (thickness: 100 μm) prepared by etching and removing the copper foil 1 from the metal-clad laminate 3 was 27.6 ppm / K.

(Reference Example 1)
A copper foil 1, a resin sheet A, a polyimide film 1, a resin sheet A and a copper foil 1 were laminated in this order, and pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa to prepare a metal-clad laminate 4. .
The evaluation results of the metal-clad laminate 4 are as follows.
Dimensional change after etching in MD direction: -0.04%
Dimensional change after etching in TD direction: -0.05%
Dimensional change after heating in MD direction: -0.12%
Dimensional change after heating in TD direction: -0.14%
The metal-clad laminate 4 had no warpage and no dimensional change. The CTE of the resin laminate 4 (thickness: 100 μm) prepared by etching and removing the copper foil 1 in the metal-clad laminate 4 was 23.9 ppm / K.

  Examples 1 and 2 also show that the dimensional change after etching and the dimensional change after heating are low even when compared with Comparative Example 1 and Reference Example 1, respectively. In Comparative Example 1, lamination was performed by thermocompression bonding at 320 ° C., and there was no problem in adhesion. However, the same thermocompression bonding conditions (temperature: 180 ° C., time: 2 hours, pressure) as in Examples 1 and 2 were used. A sufficient adhesion could not be obtained by thermocompression bonding at 3.5 MPa). Reference Example 1 was performed to verify the position configuration of the resin sheet A.

[Example 3]
A single-sided metal-clad laminate 1 is prepared, and a resin solution A for an adhesive layer is applied on the surface on the side of the insulating resin layer so as to have a thickness of 50 μm after being dried. Drying was performed at 15 ° C. 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 is overlapped with the surface of the other single-sided metal-clad laminate 1 on the insulating resin layer side, and then pressure-bonded at 180 ° C. for 2 hours at 3.5 MPa. Thus, a metal-clad laminate 1 ′ was prepared.
The evaluation results of the metal-clad laminate 1 'are as follows.
Dimensional change after etching in MD direction: -0.03%
Dimensional change after etching in the TD direction: -0.03%
Dimensional change after heating in MD direction: -0.02%
Dimensional change after heating in TD direction: -0.02%
The metal-clad laminate 1 ′ did not warp and had no problem in dimensional change. The CTE of the resin laminate 1 ′ (thickness: 100 μm) prepared by etching and removing the copper foil 1 from the metal-clad laminate 1 ′ was 23.1 ppm / K.

[Example 4]
Two single-sided metal-clad laminates 1 with an adhesive layer were prepared, and the surfaces of the adhesive layers were overlapped with each other, and then pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa to prepare a metal-clad laminate 5.
The evaluation results of the metal-clad laminate 5 are as follows.
Dimensional change after etching in MD direction: -0.03%
Dimensional change after etching in the TD direction: -0.03%
Dimensional change after heating in MD direction: -0.03%
Dimensional change after heating in TD direction: -0.03%
The metal-clad laminate 5 was not warped and had no problem in dimensional change. The CTE of the resin laminate 5 (thickness: 150 μm) prepared by etching and removing the copper foil 1 in the metal-clad laminate 5 is 23.8. ppm / K.

[Example 5]
A single-sided metal-clad laminate 1 is prepared, and a resin solution A for an adhesive layer is applied on the surface on the side of the insulating resin layer so as to have a thickness of 75 μm after being dried. Drying was performed at 25 ° C. for 25 minutes to prepare a single-sided metal-clad laminate 2 with an adhesive layer.
Two single-sided metal-clad laminates 2 with an adhesive layer were prepared, and the surfaces of the adhesive layers were overlapped with each other, and then pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa to prepare a metal-clad laminate 6.
The evaluation results of the metal-clad laminate 6 are as follows.
Dimensional change after etching in the MD direction: -0.01%
Dimensional change after etching in TD direction: -0.01%
Dimensional change after heating in MD direction: 0.01%
Dimensional change after heating in TD direction: 0.02%
The metal-clad laminate 6 did not warp and had no problem in dimensional change. The CTE of the resin laminate 6 (thickness: 200 μm) prepared by etching and removing the copper foil 1 in the metal-clad laminate 6 is 22.8. ppm / K.

(Synthesis example 5)
Under a stream of nitrogen, a 500 ml separable flask was charged with 44.98 g of BTDA (0.139 mol), 75.02 g of DDA (0.140 mol), 168 g of NMP and 112 g of xylene. For 30 minutes to prepare a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 4.5 hours, and 112 g of xylene was added to prepare a polyimide adhesive solution 1 in which imidization was completed. The solid content in the obtained polyimide adhesive solution 1 was 29.1% by weight, and the viscosity was 7,800 cps. The weight average molecular weight (Mw) of the polyimide was 87,700.

(Synthesis example 6)
34.4 g (10 g as a solid content) of the polyimide adhesive solution 1 obtained in Synthesis Example 5, 1.25 g of N-12 and 2.5 g of Exolit OP935 (manufactured by Clariant Japan KK) were blended. 297 g of NMP and 3.869 g of xylene were added and diluted to prepare a resin solution C for an adhesive layer.

<Preparation of resin sheet C for adhesive layer>
After drying the resin solution C for the adhesive layer on the silicone-treated surface of the release substrate (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness becomes 50 μm after drying, the resin solution C is heated at 80 ° C. for 15 minutes. After drying by heating and further drying at 120 ° C. for 15 minutes, the resin sheet C was prepared by peeling off from the release substrate. The resin sheet C was heated in an oven at 120 ° C. for 2 hours and at 170 ° C. for 3 hours in order to evaluate physical properties after curing, thereby preparing a cured resin sheet D. The cured resin sheet D had a Tg of 95 ° C., a storage modulus at 50 ° C. of 1220 MPa, and a maximum value of storage modulus at 180 ° C. to 260 ° C. of 26 MPa.

[Example 6]
A single-sided metal-clad laminate 1 is prepared, and a resin solution C for an adhesive layer is applied to the surface on the side of the insulating resin layer so as to have a thickness of 50 μm after being dried. Drying was performed at 15 ° C. 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 surface of the single-sided metal-clad laminate 1 on the insulating resin layer side, and then pressed at 180 ° C. for 2 hours under a pressure of 3.5 MPa. A metal-clad laminate 7 was prepared.
The evaluation results of the metal-clad laminate 7 are as follows.
Dimensional change after etching in MD direction: -0.02%
Dimensional change after etching in TD direction: -0.02%
Dimensional change after heating in MD direction: -0.03%
Dimensional change after heating in TD direction: -0.03%
The metal-clad laminate 7 had no warpage and no dimensional change. The CTE of the resin laminate 7 (thickness: 100 μm) prepared by etching and removing the copper foil 1 from the metal-clad laminate 7 was 23.4 ppm / K.

  Further, any one-sided metal-clad laminate with an adhesive layer described in the examples can 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.

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

100: metal-clad laminate, 101: metal layer, 110: polyimide layer, 111: non-thermoplastic polyimide layer, 112: thermoplastic polyimide layer, 120: adhesive polyimide layer, 130: single-sided metal-clad laminate

Claims (7)

A first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one surface of the first metal layer;
A second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one surface of the second metal layer;
The first single-sided metal-clad laminate and the second single-sided metal-clad laminate were disposed so as to be in contact with the first insulating resin layer and the second insulating resin layer. An adhesive layer, and a metal-clad laminate comprising:
The adhesive layer is made of a thermoplastic resin or a thermosetting resin, and has the following conditions (i) to (iii);
(I) the storage modulus at 50 ° C. is 1800 MPa or less;
(Ii) the maximum value of the storage modulus in a temperature range of 180 ° C. to 260 ° C. is 800 MPa or less;
(Iii) the glass transition temperature (Tg) is 180 ° C. or less;
A metal-clad laminate characterized by satisfying the following.   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 to 500 μm, and the ratio of the thickness T2 of the adhesive layer to the total thickness T1 (T2 The metal-clad laminate according to claim 1, wherein (/ T1) is in the range of 0.5 to 0.8. Both the first insulating resin layer and the second insulating resin layer have a multilayer structure in which a thermoplastic polyimide layer, a non-thermoplastic polyimide layer, and a thermoplastic polyimide layer are laminated in this order,
The metal-clad laminate according to claim 1, wherein the adhesive layer is provided in contact with the two thermoplastic polyimide layers. The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains a tetracarboxylic acid residue and a diamine residue, and a diamine represented by the following general formula (1) with respect to 100 mol parts of all diamine residues. The metal-clad laminate according to claim 3, wherein the content of the diamine residue derived from the compound is 80 mol parts or more.

[In the formula (1), the linking group Z represents a single bond or -COO-, and Y independently represents a monovalent hydrocarbon having 1 to 3 carbon atoms which may be substituted with a halogen atom or a phenyl group, or carbon. It represents 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. ]   The thermal expansion coefficient of the first insulating resin layer, the adhesive layer, and the second insulating resin layer as a whole is in a range of 10 ppm / K or more and 30 ppm / K or less. The metal-clad laminate as described.   The metal-clad laminate according to any one of claims 1 to 5, wherein both the first metal layer and the second metal layer are made of copper foil. A circuit board obtained by processing the first metal layer and / or the second metal layer in the metal-clad laminate according to any one of claims 1 to 6 into wiring.

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