TWI719955B - Three-layer film, method for forming three-layer film, laminated sheet, and printed circuit board - Google Patents

Abstract

A three-layer film includes a polyimide resin film and liquid crystal polymer layers which include a hydroxycarboxlic acid as a mesogenic group and are laminated on both surfaces of the polyimide resin film. A thickness of the polyimide resin film (T1) and thicknesses of the liquid crystal polymer layers which include the hydroxycarboxlic acid as the mesogenic group (T2) satisfy the following relational expressions (a) and (b), where two T2s are independent from each other and may be the same or different.

(a) 20 μm≦T1≦50 μm

(b)0.3≦T2/T1≦1.5

Description

Three-layer film, manufacturing method of three-layer film, laminated board and printed circuit board

The present invention relates to a three-layer film, a method for manufacturing a three-layer film, a laminate and a printed circuit board.

Printed wiring boards (printed circuit boards, printed circuit boards) used in electronic devices such as mobile phones, personal computers, and digital home appliances are used in laminates with a metal layer on the insulating layer. As such a laminate, for example, a laminate obtained by laminating a layer made of a conductor such as a metal foil and a layer made of a polyimide resin film as an insulating layer is known (for example, Patent Document 1~ 2). In addition, Patent Document 3 describes a laminate in which a copper foil is used as a metal layer and a liquid crystal polyester resin layer is laminated as an insulating layer.

Polyimide resin has water absorption and poor moisture resistance. In addition, since it is a non-thermoplastic resin, it is impossible to directly laminate the metal foil. Therefore, for example, Patent Documents 4 to 5 describe the use of liquid crystal polymer films and polyimide resins. The laminate is used as an insulating layer. As the liquid crystal polymer film, those described in Patent Documents 6 to 9 can be cited. The water absorption of the polyimide resin will have a great impact on the electrical properties of the printed wiring board. Therefore, the method of using the liquid crystal polymer film is important for making the electrical properties of the printed wiring board good.

[Prior technical literature] 〔Patent Literature〕

[Patent Document 1] JP 2006-008976 A

[Patent Document 2] JP 2013-032532 A

[Patent Document 3] JP 2007-106107 A

[Patent Document 4] JP 2008-290424 A

[Patent Document 5] JP 2008-290425 A

[Patent Document 6] JP 2013-189535 A

[Patent Document 7] JP 2004-315678 A

[Patent Document 8] JP 2007-238915 A

[Patent Document 9] JP 2013-001902 A

However, the characteristics required for printed wiring boards are increasing, and there is still room for improvement in laminates used for printed wiring boards.

The present invention has been made in view of the above-mentioned facts, and its subject is to provide a laminate for use in printed wiring boards with excellent dimensional stability and electrical properties The three-layer film and the manufacturing method of the three-layer film.

The first aspect of the present invention is a three-layer film, which is laminated on both sides of a polyimide resin film with a liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen, and the aforementioned polyimide resin The thickness (T1) of the film and the thickness (T2) of the liquid crystal polymer layer with hydroxycarboxylic acid as the mesogen mentioned above satisfy the following relational formulas (a) and (b) (However, the two T2 are independent of each other. It can be the same or different).

(a) 20 μ m≦T1≦50 μ m

(b) 0.3≦T2/T1≦1.5

In the first aspect of the present invention, the liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen group preferably contains structural units derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid.

In the first aspect of the present invention, the liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen group preferably further contains the following structural units (1) and (2).

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

The second aspect of the present invention is a laminate in which the three-layer film of the aforementioned first aspect is used as an insulating layer, and a metal layer is formed on at least one side of the insulating layer.

In the second aspect of the present invention, the maximum height (Rz) of the aforementioned metal layer is preferably formed at 0.5-2.5 μm.

In the second aspect of the present invention, the aforementioned metal layer preferably contains copper.

The third aspect of the present invention is a printed circuit board using the laminate of the aforementioned fifth aspect.

The fourth aspect of the present invention is a method for manufacturing a three-layer film, which includes coating a polyimide resin film with a liquid composition containing a solvent and a liquid crystal polymer, and coating the liquid composition with the liquid composition The method for manufacturing a three-layer film of the liquid composition coating step of the aforementioned polyimide resin film, the solvent removal step of removing the solvent in the aforementioned liquid composition, and the heat treatment step, wherein as the aforementioned liquid crystal polymer, It contains structural units derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2).

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

The fifth aspect of the present invention is a method for manufacturing a three-layer film, which comprises impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer, and coating the polyimide resin film with the liquid composition. The method for producing a three-layer film of the impregnation step of the imine resin film, the solvent removal step of removing the solvent in the aforementioned liquid composition, and the heat treatment step, wherein the liquid crystal polymer contains 2-hydroxybenzoin as the aforementioned liquid crystal polymer The structural unit of acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2).

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

The sixth aspect of the present invention is the manufacture of a three-layer film The method includes the steps of preparing a liquid composition containing a solvent and a liquid crystal polymer, and a polyimide resin liquid composition that is a precursor of the polyimide resin; and sequentially depositing the liquid composition on a support The step of coating the composition, the aforementioned polyamide resin liquid composition, and the aforementioned liquid composition into three layers; the solvent removal step of removing the solvent in the aforementioned three-layer liquid composition; and the three-layer film The method for producing a three-layer film in the forming step, wherein as the aforementioned liquid crystal polymer, it contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2) .

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

According to the present invention, it is possible to provide a three-layer film with excellent dimensional stability and electrical characteristics when used in a laminate for a printed wiring board, and a method for manufacturing the three-layer film.

20‧‧‧Three-layer film

21‧‧‧Polyimide resin film

22a, 22b‧‧‧Liquid crystal polymer layer

30a, 30b‧‧‧Metal layer

3‧‧‧Dipping tank

4‧‧‧Guide roller

5‧‧‧Squeeze roller

5A、5B‧‧‧roller

10‧‧‧Polyimide resin film

11‧‧‧Polyimide resin film just after being impregnated with liquid composition

12‧‧‧Liquid composition impregnated with polyimide resin film

W‧‧‧Liquid composition

G ₁ ‧‧‧Guide roller

[Figure 1] A schematic diagram for explaining the three-layer film of the present invention.

[Figure 2] A schematic diagram for explaining a laminate using the three-layer film of the present invention.

[Fig. 3] A schematic diagram for explaining the manufacturing method of the three-layer film of the third aspect of the present invention.

≪Three-layer film≫

First, the three-layer film of the first aspect of the present invention is explained using FIG. 1.

Fig. 1 shows a three-layer film 20 of the present invention. The three-layer film 20 is on both sides of the polyimide resin film 21, and is laminated with liquid crystal polymer layers 22a and 22b using hydroxycarboxylic acid as the mesogen. In other words, the three-layer film 20 includes liquid crystal polymer layers 22a and 22b with hydroxycarboxylic acid as mesogen, and a polyimide resin film 21 sandwiched between the liquid crystal polymer layers 22a and 22b.

For the three-layer film 20, the thickness (T1) of the polyimide resin film 21 and the respective thickness (T2) of the liquid crystal polymer layers 22a and 22b with hydroxycarboxylic acid as the mesogen, satisfy the following relational formula (a ) And (b), and the two T2s (T2a and T2b in Figure 1) are independent of each other and can be the same, It can also be different.

(a) 20 μ m≦T1≦50 μ m

(b) 0.3≦T2/T1≦1.5

〔Polyimide resin film〕

Polyimide resin is a condensation type polyimide obtained by polycondensation using diamines and tetracarboxylic dianhydride as starting materials. There are no particular restrictions on the diamines, and aromatic diamines, alicyclic diamines, aliphatic diamines, etc., which are generally used in the synthesis of polyimides, can be used. The diamines may be used alone, or two or more of them may be used in combination.

Moreover, as the tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, etc. can be used, and it does not specifically limit. Tetracarboxylic dianhydride may be used alone or in combination of two or more kinds.

In addition, at least any one of the above-mentioned diamines and tetracarboxylic dianhydrides may have one or more selected from the group consisting of fluoro or trifluoromethyl, hydroxyl, carbonyl, heterocyclic, and long-chain alkane. At least one kind of functional group of a group such as a group.

Among such polyimides, from the viewpoint of mechanical strength and flexibility when forming the polyimide resin film 21, it is particularly preferable to use aromatic tetracarboxylic dianhydrides as the tetracarboxylic dianhydride.

Regarding the diamines, aromatic diamines, alicyclic diamines, and aliphatic diamines may be used alone, or two or more of them may be used in combination.

In addition, from the viewpoint of mechanical strength and flexibility when forming the polyimide resin film 21, the diamine is preferably an aromatic diamine.

As the polyimide resin film, commercially available polyimide resin (PI) films can be used. Examples include PI films (U-PILEX S, U-PILEX R) manufactured by Ube Industries Co., Ltd., Toray DuPont PI film (Kapton), PI film (IF30, IF70, LV300) manufactured by SKC Kolon PI.

In the present invention, the thickness (T1) of the polyimide resin film satisfies the following formula (a).

(a) 20 μ m≦T1≦50 μ m

Here, the thickness of the polyimide resin film is an average value obtained by measuring the thickness with a contact thickness meter at any 5 locations of the polyimide resin film. In addition, when measuring the thickness of a polyimide resin film, it is difficult to directly apply a contact thickness meter. It is also possible to measure the entirety in the same manner as the above in a state where other layers such as liquid crystal polymer layers 22a and 22b are laminated. The thickness is calculated by taking the difference between the thickness (measured by the same method as the above) of the other layer to be laminated.

In the present invention, from the viewpoint of easy availability, the thickness of the polyimide resin film is preferably 20 μm≦T1≦40 μm, more preferably 20 μm≦T1≦30 μm.

When the thickness of the polyimide resin film is more than the above lower limit, the insulating properties and posture retention function of the three-layer film can be ensured, and when the thickness is below the above upper limit, moderate flexibility can be ensured.

〔Liquid Crystal Polymer〕

Liquid crystal polymerization used in the liquid crystal polymer layer of the three-layer film of the present invention It is a liquid crystal polymer with hydroxycarboxylic acid as the mesogen. As a typical example, it can be exemplified by polymerization of singly or plural kinds of aromatic hydroxycarboxylic acids; singly or plural kinds of aromatic hydroxycarboxylic acids and selected from aromatic dicarboxylic acids, aromatic diols, aromatics Those obtained by polymerizing at least one compound of the group of hydroxylamine and aromatic diamine (polycondensation); and those obtained by polymerizing polyester such as polyethylene terephthalate and aromatic hydroxycarboxylic acid.

The mesogenic group derived from hydroxycarboxylic acid is not particularly limited, and preferably contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid. Here, the mesogen group refers to a molecular chain contained in a liquid crystal molecule that is rod-shaped or plate-shaped and has high rigidity along the long chain of the molecule. The mesogenic group may exist in either or both of the main chain or the side chain of the liquid crystal polymer, but it is preferable to exist in the main chain if high heat resistance is required.

In the present invention, the liquid crystal polymer preferably contains structural units derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid.

The liquid crystal polymer preferably has a repeating unit represented by the following (1) (hereinafter referred to as "repeating unit (1)"), and more preferably has a repeating unit (1), which is represented by the following formula (2) Repeating unit (hereinafter referred to as "repeating unit (2)").

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

The aforementioned halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the aforementioned alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-hexyl, 2-ethyl The hexyl group, n-octyl group and n-decyl group preferably have a carbon number of 1-10.

Examples of the aforementioned aryl group include phenyl, o-tolyl, m-tolyl, p-tolyl, 1-naphthyl, and 2-naphthyl, and the carbon number is preferably 6-20.

When the hydrogen atoms in the aforementioned groups represented by Ar ¹ to Ar ⁴ are substituted by these groups, the number is preferably 2 or less for each of the aforementioned groups represented ^{by Ar 1} to Ar ^4, More preferably, it is one.

Examples of the aforementioned alkylene group include methylene, ethylene, isopropylene, n-butylene, and 2-ethylhexylene, and the number of carbon atoms is preferably 1-10.

The repeating unit (1) is a repeating unit derived from a specific aromatic dicarboxylic acid. As the repeating unit (1), preferably Ar ¹ is p-phenylene (repeating unit derived from terephthalic acid), Ar ¹ is m-phenylene (repeating unit derived from isophthalic acid), Ar ¹ is 2,6-naphthylene (from the repeating unit of 2,6-naphthalenedicarboxylic acid), and Ar ¹ is diphenyl ether-4,4'-diyl (from diphenyl ether- 4,4'-repeating unit of dicarboxylic acid).

The repeating unit (2) is a repeating unit derived from a specific aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (2), preferably Ar ² is p-phenylene (repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ² is 4,4'-linked Phenylene (from the repeating unit of 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl or 4,4'-diaminobiphenyl).

The content of the repeating unit (1) is relative to the total amount of all repeating units (by dividing the mass of each repeating unit constituting the liquid crystal polymer by the formula weight of each repeating unit, the equivalent amount of substance of each repeating unit is obtained (Mole), and the total value) is preferably 40 mol% or less, more preferably 10 mol% or more and 37.5 mol% or less, still more preferably 20 mol% or more, and 37.5 mol% or less, and still more preferably 25 mol% or more and 37.5 mol% or less.

Similarly, the content of the repeating unit (2) relative to the total amount of all repeating units is preferably 40 mol% or less, more preferably 10 mol% or more and 37.5 mol% or less, and still more preferably 20 mol% or more and 37.5 mol% or less, and still more preferably 25 mol% or more and 37.5 mol% or less.

The content of mesogen group derived from hydroxycarboxylic acid is preferably 55 mol% or less, more preferably 20 mol% or more and 50 mol% or less, relative to the total amount of all repeating units. It is preferably 25 mol% or more and 45 mol% or less, and still more preferably 30 mol% or more and 45 mol% or less. In the liquid crystal polymer, when the content of mesogen groups derived from hydroxycarboxylic acid is higher than 55 mol%, the resulting liquid crystal polymer is insoluble The solvent tends to be described later, so it tends to be difficult to obtain a liquid crystal polymer layer.

The ratio of the content of the repeating unit (1) to the content of the repeating unit (2) is expressed by [the content of the repeating unit (1)]/[the content of the repeating unit (2)] (mole/mole), preferably 0.9/1~1/0.9, more preferably 0.95/1~1/0.95, still more preferably 0.98/1~1/0.98.

Furthermore, the liquid crystal polymer may each independently have two or more repeating units (1) to (2). In addition, the liquid crystal polymer may have repeating units other than repeating units (1) to (2), and its content is preferably more than 0 mol% and 10 mol% relative to the total amount of all repeating units. , More preferably, it is more than 0 mol% and 5 mol% or less.

Liquid crystal polymer, if one or both of X and Y are imine groups as the repeating unit (2), that is, it has repeating units derived from a specific aromatic hydroxylamine, and a repeating unit derived from an aromatic diamine When either or both of the repeating units are excellent in solvent solubility, it is preferred. When only one or both of X and Y are imino groups as the repeating unit (2), then Better.

The liquid crystal polymer may be a mesogen group derived from a hydroxycarboxylic acid and a random combination with the repeating units (1) to (2). As long as it exhibits liquid crystallinity, it may also be a block copolymer.

The liquid crystal polymer is preferably produced by melt-polymerizing raw material monomers corresponding to the repeating unit constituting it, and solid-phase polymerization of the resulting polymer (prepolymer). Thereby, high-molecular-weight liquid crystal polymers with high heat resistance or high strength/rigidity can be produced with good operability. Melt polymerization is also possible It is carried out in the presence of a catalyst. Examples of the catalyst include metal compounds such as magnesium acetate, tin (II) acetate, titanium tetrabutoxide, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, or 4- Nitrogen-containing heterocyclic compounds such as (dimethylamino)pyridine and 1-methylimidazole are preferably nitrogen-containing heterocyclic compounds.

The flow initiation temperature of the liquid crystal polymer is preferably 250°C or higher, more preferably 250°C or higher and 350°C or lower, and still more preferably 260°C or higher and 330°C or lower. The higher the flow initiation temperature, the easier it is to improve the heat resistance or strength/rigidity, but when it is too high, the solubility to organic solvents is likely to decrease, or the viscosity of the solution is likely to increase.

Furthermore, the flow start temperature, also called flow temperature or flow temperature, is based on a capillary rheometer. ^{Under a load of 9.8MPa (100kgf/cm 2} ), the temperature rises at a rate of 4°C/min while simultaneously increasing The liquid crystal polymer melts, and when extruded from a nozzle with an inner diameter of 1mm and a length of 10mm, it shows 4800Pa. The viscosity temperature of s(48000poise), which is the standard for the molecular weight of liquid crystal polymers (see Koide Naoyi, "Liquid Crystal Polymer-Synthesis, Forming, Application -", CMC Co., Ltd., June 5, 1987 Day, p.95).

In the present invention, the liquid crystal polymer layer can be formed by a liquid composition containing the aforementioned liquid crystal polymer and a solvent. The solvent is preferably an organic solvent. The organic solvent is suitably selected to dissolve the liquid crystal polymer used. Specifically, it can be used at a concentration of 1% by mass or more at 50°C ([Liquid Crystal Polymer]/[Liquid Crystal Polymer]物+Organic solvent]) to dissolve the person.

Examples of organic solvents include dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, o-dichlorobenzene and other halogenated hydrocarbons; p-chlorophenol, Halogenated phenols such as pentachlorophenol and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane, etc.; ketones such as acetone and cyclohexanone; ethyl acetate, γ-butyrolactone, etc. Esters; carbonates such as ethylene carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; N,N-dimethyl Amine-based solvents such as formamide, N,N-dimethylacetamide, and N-methylpyrrolidone (organic solvents with amide bonds in the molecule); urea compounds such as tetramethylurea; nitrate Nitro compounds such as methyl methane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and cyclobutane; and phosphorus compounds such as hexamethyl amide and tri-n-butyl phosphoric acid. In addition, two or more organic solvents among these organic solvents can also be used in combination.

As the organic solvent, in terms of low corrosiveness and easy handling, a solvent mainly composed of aprotic compounds (aprotic solvent) is preferred, especially a solvent mainly composed of aprotic compounds without halogen atoms. Solvent. As the aprotic compound, it is preferable to use N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc., in terms of easily dissolving the liquid crystal polymer. Amide-based solvents. In addition, the proportion of the aprotic compound in the entire organic solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and still more preferably 90% by mass or more And 100% by mass or less.

In addition, as an organic solvent, it is preferable to use a compound having a dipole moment of 3 to 5 (unit: Debye) in terms of easily dissolving the liquid crystal polymer As the main component solvent, it is more preferable to use the above-mentioned aprotic compound with a dipole moment of 3~5.

In addition, the proportion of the compound having a dipole moment of 3 to 5 in the entire organic solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and still more preferably It is 90% by mass or more and 100% by mass or less.

Aprotic compounds and compounds with a dipole moment of 3 to 5, such as dimethyl sulfoxide (dipole moment: 4.1 Debye), N,N-dimethylacetamide (3.7 Debye), N , N-Dimethylformamide (3.9 Debye), N-Methylpyrrolidone (4.1 Debye).

Moreover, as an organic solvent, in terms of easy removal, it is preferably a solvent mainly composed of a compound having a boiling point of 220°C or less at 1 atm, and it is more preferable to use the above-mentioned aprotic compound, and the boiling point at 1 atm is Compounds below 220°C. In addition, the ratio of the compound having a boiling point of 220°C or less at 1 atmosphere in the total organic solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and More preferably, it is 90% by mass or more and 100% by mass or less.

As an aprotic compound, a compound having a boiling point of 220°C or lower at 1 atmosphere pressure can be exemplified by N,N-dimethylacetamide (boiling point: 160°C), N,N-dimethylformamide (boiling point) : 153°C), N-methylpyrrolidone (boiling point: 202°C).

(Liquid composition)

The content of the liquid crystal polymer in the liquid composition, relative to the total amount of the liquid crystal polymer and the organic solvent, is preferably 5 mass% or more and 60 mass% or less, more preferably 10 mass% or more and 50 mass% or less , It is more preferably 15% by mass or more and 45% by mass or less, and it is appropriately adjusted according to the way that a liquid composition of the desired viscosity can be obtained.

In addition, the liquid composition may contain one or more fillers, additives, resins other than the liquid crystal polymer, and other components within a range that does not impair the effects of the three-layer film of the present invention.

Examples of fillers include inorganic fillers such as silica, alumina, titanium oxide, barium titanate, strontium titanate, aluminum hydroxide, calcium carbonate, etc.; and leveling agents, hardened epoxy resins, and cross-linked benzene The content of organic fillers such as guanamine resins and crosslinked acrylic resins is preferably 0 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the liquid crystal polymer.

Examples of additives include leveling agents, defoamers, antioxidants, ultraviolet absorbers, flame retardants, and coloring agents. The content thereof is preferably 0 parts by mass or more relative to 100 parts by mass of the liquid crystal polymer. 5 parts by mass or less.

Examples of resins other than liquid crystal polymers include polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfide, polyphenylene ether and its modifications, and polyether sulfide Thermoplastic resins other than liquid crystal polymers such as amines; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenol resins, epoxy resins, and cyanate resins. Content, relative to 100 parts by mass of liquid crystal polymer, Preferably it is 0 part by mass or more and 20 parts by mass or less.

The liquid composition can be prepared by mixing the liquid crystal polymer, organic solvent, and other components used as needed together or in an appropriate order. When a filler is used as another component, it is preferably prepared by dissolving a liquid crystal polymer in an organic solvent to obtain a liquid composition, and then dispersing the filler in the liquid composition.

In the present invention, the thickness (T2) of the liquid crystal polymer layer satisfies the following formula (b) in relation to the thickness (T1) of the aforementioned polyimide resin film.

(b) 0.3≦T2/T1≦1.5

In the present invention, the "thickness of the liquid crystal polymer layer" means the respective thickness of the liquid crystal polymer layer laminated on both sides of the polyimide resin film. Specifically, T2a and T2b in FIG. 1 each satisfy the above-mentioned formula (b).

Here, the thickness of the liquid crystal polymer layer is an average value obtained by measuring the thickness with a contact thickness meter at any 5 locations of the liquid crystal polymer layer. Furthermore, when measuring the thickness of the liquid crystal polymer layer, it is difficult to directly apply the contact thickness meter. It is also possible to measure the overall thickness in the same manner as above in the state where other layers such as polyimide resin film are laminated. It is calculated by taking the difference between the thickness (measured by the same method as above) of the other layer to be laminated.

In the present invention, the relationship between the thickness (T2) of the liquid crystal polymer layer and the thickness (T1) of the aforementioned polyimide film resin film is preferably in the range of 0.35≦T2/T1≦1.4, particularly preferably 0.4≦T2/ T1≦1.3 range Surrounding.

In the three-layer film of the present invention, for example, when a polyimide resin film with a thickness of 25 μm is used, the thickness of the liquid crystal polymer layer is preferably 7.5 μm-50 μm, more preferably 8 μm-40 μm, particularly preferably 9 μm-35 μm.

In the three-layer film of the present invention, the thickness of the liquid crystal polymer layer (T2a and T2b in FIG. 1) are independent of each other, and may be the same or different. In the present invention, they are preferably the same, but as long as the effects of the present invention are exerted and the three-layer film does not warp in the range, it can be adjusted/changed appropriately.

For example, when the polyimide resin film has a degree of hardness that can prevent warpage, the thickness of the liquid crystal polymer layer (T2a and T2b in FIG. 1) may also be different.

When the thickness of the liquid crystal polymer layer (T2a and T2b in FIG. 1) is different, for example, the difference between the thickness of T2a and the thickness of T2b is preferably within ±10%, more preferably within ±5%, especially preferred Within ±3%.

Liquid crystal polymer has excellent low hygroscopicity, insulation, mechanical strength, etc. Therefore, by laminating the liquid crystal polymer layer on both sides of the polyimide resin film, the hygroscopic polyimide can be made The moisture absorption of the resin film is highly suppressed. Therefore, even when a printed circuit board or the like obtained by laminating a metal on the three-layer film of the present invention is placed in a humid environment or immersed in water, the polyimide resin film can be highly suppressed. The electrical characteristics of the hygroscopicity are deteriorated.

In addition, the thickness (T2) of the liquid crystal polymer layer is in relation to the thickness (T1) of the polyimide resin film, by becoming the above-mentioned specific Below the upper limit, when a metal is laminated on the three-layer film of the present invention, the dimensional stability of the metal laminate can be improved.

Furthermore, the thickness (T2) of the liquid crystal polymer layer, in relation to the thickness (T1) of the polyimide resin film, becomes higher than the above-mentioned specific lower limit, which can highly suppress the polyimide resin film The moisture absorption effect. Therefore, when a metal is laminated on the three-layer film of the present invention, the effect of reducing the transmission loss of the metal laminate can be highly exhibited. The three-layer film of the present invention, when a metal layer is laminated on both sides of the three-layer film, can particularly exhibit a high degree of dimensional stability and transmission loss reduction effects. Therefore, the three-layer film of the present invention is preferably used in a laminate obtained by laminating a metal layer on both sides of the three-layer film.

A laminate of the three-layer film of the present invention can be suitably used. For example, as shown in FIG. 2, a metal layer 30a, 30b is laminated on both sides of the three-layer film 20 of the present invention. That is, the laminated system includes the metal layers 30a and 30b, and the three-layer film 20 sandwiched between the metal layers 30a and 30b.

The metal layer is preferably an alloy containing copper, aluminum, silver, or one or more metals selected from these. Among them, copper or copper alloys are particularly preferred from the viewpoint of having better electrical conductivity. In addition, the metal layer is preferably formed of metal foil, more preferably formed of copper foil, from the viewpoints of easy material handling, simple formation, and excellent economic efficiency. When the metal layers are provided on both sides of the three-layer film, the materials of these metal layers can be the same or different.

The thickness of the metal layer is preferably 1~50μm, more preferably 3~35μm, and More preferably, it is 5-20 μm.

Here, the thickness of the metal layer is an average value obtained by measuring the thickness with a contact thickness meter at any 5 locations of the metal layer. Furthermore, when measuring the thickness of the metal layer, it is difficult to directly apply the contact thickness meter. It is also possible to measure the overall thickness in the same way as the above in a state where other layers such as a liquid crystal polymer layer are laminated, by taking and superimposing the thickness. Calculate the difference between the thicknesses of the other layers (measured by the same method as above).

≪Method of manufacturing three-layer film 1≫

The second aspect of the present invention is the manufacturing method of the three-layer film of the first aspect of the present invention, which includes coating a liquid composition containing a solvent and a liquid crystal polymer on a polyimide resin film, The first aspect of the present invention of the liquid composition coating step of covering the polyimide resin film with the liquid composition, the solvent removal step of removing the solvent in the liquid composition, and the heat treatment step The method for producing a three-layer film, wherein as the aforementioned liquid crystal polymer, it contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) to (2).

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

[Liquid composition coating step]

The method for producing a three-layer film of the present invention includes coating a liquid composition containing a solvent and a liquid crystal polymer on a polyimide resin film, and coating the polyimide resin film with the liquid composition. -Like composition coating step.

The description of the liquid composition containing the solvent and the liquid crystal polymer and the polyimide resin film is the same as the description in the aforementioned three-layer film of the present invention.

The method of coating the aforementioned liquid composition on the polyimide resin film includes, for example, roll coating, dip coating, spray coating, curtain coating, and slit coating. , Screen printing and other methods. The temperature during coating is preferably 10-40°C.

In the present invention, the liquid composition is coated on both sides of the polyimide resin film by the above-mentioned coating method. At this time, the coating amount of the liquid composition is adjusted so that the liquid crystal polymer layer has the aforementioned specific thickness.

[Solvent removal step]

After the aforementioned [liquid composition coating step], the solvent in the aforementioned liquid composition is removed.

Here, the method for removing the solvent is not particularly limited, and it is preferably performed by evaporation of the solvent. The method for evaporating the solvent includes heating, decompression, ventilation, etc. Among them, from the viewpoint of production efficiency and operability, heating and evaporation are particularly preferred, and it is more preferred to heat and evaporate while ventilating.

The heat treatment in the solvent removal step can be appropriately selected according to the solvent used in the solution composition, and heat treatment at 60 to 200°C for 60 to 600 seconds, preferably 120 to 600 seconds. By being above the lower limit, the solvent is sufficiently removed, and the adhesion is suppressed in the obtained three-layer film.

In addition, the solvent removal in the [solvent removal step] does not need to be complete, and the remaining solvent may be removed in the subsequent [heat treatment step]. From the viewpoint of preventing the surface roughness of the liquid crystal polymer layer, it is preferable to remove the solvent first in this [solvent removal step].

〔Steps of heating treatment〕

After the aforementioned [solvent removal step], heat treatment is performed. The heating treatment may be a method of applying heat to the three-layer film under an inert gas environment for heating. The heat treatment conditions may be appropriately adjusted according to the liquid composition to be used, and for example, it may be performed in the range of 250°C to 400°C for 1 minute to 4 hours.

In the method for producing a three-layer film of the second aspect of the present invention, first, a liquid composition is applied to one side of the polyimide resin film, and the solvent in the liquid composition is removed. Then, on the other side also This operation is repeated, and finally the heat treatment is performed, whereby the three-layer film of the first aspect of the present invention can be obtained.

≪Method for manufacturing three-layer film 2≫

The third aspect of the present invention is the manufacturing method of the three-layer film of the first aspect of the present invention, which comprises impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer, as described above The liquid composition is covered with the polyimide resin film impregnation step, the solvent removal step to remove the solvent in the liquid composition, and the heat treatment step. -The structural unit of hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units.

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

〔Steps of impregnation〕

In the impregnation step, it is a liquid composition containing solvent and liquid crystal polymer The material is impregnated with a polyimide resin film. The impregnation time is preferably 30 seconds to 5 minutes. The temperature during impregnation is preferably 10-40°C.

The description of the liquid composition containing the solvent and the liquid crystal polymer and the polyimide resin film is the same as the description in the aforementioned three-layer film of the present invention.

After the impregnation step, the polyimide resin film impregnated with the liquid composition is passed between a pair of rollers whose interval is narrower than its thickness. By this step, the excessive liquid composition adhering to the surface of the polyimide resin film can be removed.

Fig. 3 is a schematic diagram for explaining a method of continuously performing an impregnation step and a roll passing step using a long polyimide resin film. However, what is shown here is an example, and the impregnation step in the present invention is not limited to what is shown here.

After the polyimide resin film 10, guide roller guide roller train is induced to move in the G direction of arrow ₁ and 4, in immersion tank immersed in a liquid composition 3 W, and then, just impregnated liquid composition The polyimide resin film 11 is pulled up from the dipping tank 3 and sent to the squeeze roll 5 provided with a pair of rolls 5A and 5B. A pair of rollers 5A and 5B are arranged oppositely to sandwich the polyimide resin film 11, and these intervals are adjusted to be at least larger than the thickness of the polyimide resin film 11 (including the polyimide resin film 11). The total thickness of the resin film 10 and the liquid composition W impregnated therein is narrower. The aforementioned polyimide resin film 11 is squeezed by passing between such a pair of rollers 5A and 5B to remove excess liquid composition and become a liquid composition that is fully impregnated inside. Polyimide resin film 12.

The pair of rollers 5A and 5B may be self-rotating (self-rotating), or may be rotated following the movement of the polyimide resin film 11 immediately after being impregnated with the liquid composition. When the pair of rollers 5A and 5B are self-rotating, the adhesion amount of the liquid composition in the liquid composition-impregnated polyimide resin film 12 can be easily adjusted, and the target liquid composition is impregnated with polyamide The surface of the imine resin film is also sufficiently smoothed, and the smoothness of the surface is improved.

The film thickness of the liquid crystal polymer layer can be adjusted to a specific film thickness by adjusting the pulling speed from the dipping tank 3 or the interval between the pair of rolls 5A and 5B in the squeeze roll 5 film.

The description of the [solvent removal step] and the [heating step] in the third aspect of the present invention is the same as the description in the aforementioned second aspect of the present invention.

Specifically, as the [solvent removal step], the liquid composition passing between the rolls 5A and 5B is impregnated with a polyimide resin film, and heat-treated at 60 to 200°C for 60 to 600 seconds, preferably 120~600 seconds.

By this heat treatment, the solvent of the liquid composition impregnated with the polyimide resin film in the liquid composition is evaporated and removed, and the desired three-layer film can be obtained.

As for the [heating step], for example, the heat treatment may be performed in the range of 250°C to 400°C for 1 minute to 4 hours. By setting the temperature and time of the heat treatment in this way, a three-layer film with reduced porosity can be stably obtained.

≪Method for manufacturing three-layer film 3≫

The fourth aspect of the present invention is the manufacturing method of the three-layer film of the first aspect of the present invention, which includes preparing a liquid composition containing a solvent and a liquid crystal polymer, and a polyimide resin precursor The step of polyamide acid resin liquid composition; the step of sequentially coating the aforementioned liquid composition, the aforementioned polyamide acid resin liquid composition, and the aforementioned liquid composition into three layers on the support; The solvent removal step of removing the solvent in the aforementioned three-layer liquid composition; and the manufacturing method of the heat treatment step, wherein as the aforementioned liquid crystal polymer, it contains 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid The structural unit and the following structural units.

(1)-CO-Ar ¹ -CO-

(2)-X-Ar ² -Y-

(In the formula, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imine The hydrogen atom in the aforementioned group represented by Ar ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group).

(3)-Ar ³ -Z-Ar ^4-

(Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group).

〔Polyamide resin liquid composition〕

Polyimide resin is obtained by dehydration conversion reaction from polyimide precursor, namely polyimide acid. The method of carrying out this conversion reaction has been Two methods are known: the thermal hardening method using only heat, and the chemical hardening method using a chemical dehydrating agent.

Polyamide acid can be obtained by polymerizing tetracarboxylic dianhydride and diamine as raw materials as described in Patent Document 1, for example. By heating the polyamide acid at 200°C or higher (thermal curing method) or chemical ring-closing agent (chemical curing method), dehydration/cyclization reaction can be carried out to obtain polyimide resin.

[Steps of sequentially coating the liquid composition containing the solvent and the liquid crystal polymer, the polyamide resin liquid composition, and the liquid composition containing the solvent and the liquid crystal polymer on the support into three layers]

In this step, as a support, glass or the like is usually used, but a conductor may also be used. Examples of the conductor include metal plates or metal foils such as gold, silver, copper, aluminum, nickel, and stainless steel.

The method of casting a liquid composition containing a solvent and a liquid crystal polymer and a polyamide resin liquid composition on a support is to cast the aforementioned liquid composition containing a solvent and a liquid crystal polymer or polyamide resin The liquid composition is filtered with a filter or the like as needed, and the liquid composition containing the solvent and the liquid crystal polymer and the foreign matter contained in the polyamide resin liquid composition are removed, and then applied to the support by roller coating Various methods such as cloth method, dip coating method, spray coating method, spin coating method, curtain coating method, slit coating method, screen printing method, etc., the surface is smoothly and uniformly cast, and then, It can be obtained by removing the solvent.

On the support, the liquid composition containing solvent and liquid crystal polymer The compound, the polyamide resin liquid composition, and the liquid composition containing the solvent and the liquid crystal polymer are coated in this order into three layers. At this time, the coating amount of the liquid composition containing the solvent and the liquid crystal polymer is adjusted so that the liquid crystal polymer layer has the aforementioned specific thickness.

The description of the [solvent removal step] in the fourth aspect of the present invention is the same as the description in the aforementioned second aspect of the present invention.

〔Steps of forming three-layer thin film〕

Then heat treatment, the support is peeled off, and a three-layer film can be obtained. Here, it is also possible to treat with a chemical ring-closing agent instead of the heat treatment. At this time, the chemical ring-closing agent can be used to obtain polyimine from polyamide acid. For example, pyridine, acetic anhydride, benzoic acid, etc. can be used. During the heat treatment, the temperature range of 250~400℃ is sufficient in a nitrogen environment.

In the method for manufacturing a three-layer film of the fourth aspect of the present invention, a liquid composition containing a solvent and a liquid crystal polymer is first coated on the support, and the solvent in the liquid composition is removed. Next, the polyamide resin liquid composition is applied, and the solvent of the polyamide resin liquid composition is removed. Further, a liquid composition containing a solvent and a liquid crystal polymer is applied, and the solvent in the liquid composition is removed. Finally, heat treatment or chemical ring-closing agent is used to peel off the support, thereby obtaining a three-layer film.

In addition, in the method for producing a three-layer film of the fourth aspect of the present invention, a liquid composition containing a solvent and a liquid crystal polymer, a polyamide resin liquid composition, and a liquid composition containing a solvent and a liquid crystal polymer are sequentially coated on the support. Solvent and liquid crystal polymer Liquid composition, and remove the solvent in the aforementioned liquid composition. Finally, heat treatment or chemical ring-closing agent is used to peel off the support, thereby obtaining a three-layer film.

≪Laminates≫

The fifth aspect of the present invention uses the three-layer film obtained from the second to fourth aspects as an insulating layer, and a laminate with a metal layer formed on at least one side of the insulating layer.

The laminate of the present invention only needs to have a metal layer formed on at least one side of the aforementioned three-layer film, but it is preferable to laminate a metal layer on both sides. That is, the laminate preferably includes the first and second metal layers, and a three-layer thin film sandwiched between the first and second metal layers. As a laminate with metal layers laminated on both sides of the aforementioned three-layer film, more specifically, it is the laminate shown in FIG. 2, and 30a and 30b in FIG. 2 are laminates with metal layers.

The metal layer laminated on the above three-layer film is described.

The metal layer in the laminate of the present invention is a copper foil with a tensile elastic modulus of 60 GPa or less and a breaking point stress of 150 MPa or less after heat treatment at 300°C. Regarding the lower limit of the tensile modulus, the practical range is 10 GPa or more, preferably 20 GPa or more. Regarding the lower limit of the breaking point stress, the practical range is preferably 20 MPa or more, particularly preferably 30 MPa or more. The type of metal layer used in the present invention can be a layer formed by electrolysis or a layer formed by rolling. As an example of a metal layer with the above characteristics, in order to obtain copper foil, it can be known as High Temperature Elongation (high temperature and high elongation copper foil, hereinafter referred to as "HTE copper foil") or rolled copper foil commercially available, select the tensile modulus of elasticity and breaking point stress using the method specified in JIS C2151.

The thickness of the metal layer used in the laminate of the present invention is preferably in the range of more than 5 μm and 35 μm or less. Particularly preferred is the range of 9-28μm. When the thickness of the metal layer is in the above range, the tension of the metal layer is easy to adjust during the manufacture of the laminate, and the flexibility of the obtained laminate is improved, which is preferable.

Here, the thickness of the metal layer is an average value obtained by measuring the thickness with a contact thickness meter at any 5 locations of the metal layer. In addition, when measuring the thickness of the metal layer, it is difficult to directly apply the contact thickness meter. It is also possible to measure the overall thickness in the same way as the above in the state where three layers of films are superimposed. It is calculated by the difference of the thickness of the layer (measured by the same method as above).

In addition, the maximum height (Rz) of the metal layer in the laminate is preferably in the range of 0.5 to 2.5 μm, more preferably in the range of 0.6 to 2.4 μm, particularly preferably in the range of 0.6 to 2.2 μm.

Specifically exemplified as the preferred metal layer to which the present invention is applied, copper foil is preferred. Among them, as HTE copper foil, SQ-HTE copper foil (manufactured by Mitsui Mining & Mining Co., Ltd.), 3EC-M3S-HTE copper Foil (manufactured by Mitsui Metal Mining Co., Ltd.), NS-HTE copper foil (manufactured by Mitsui Metal Mining Co., Ltd.), 3EC-HTE copper foil (manufactured by Mitsui Mining Co., Ltd.), F2-WS copper foil (manufactured by Furukawa Electric Co., Ltd.), HLB (Japan) Electrolysis company), CF-T4X-DS-SVR (Fukuda Metal Foil Powder Co., Ltd.), etc.; as rolled copper foil, for example, RCF-T5B-HPC (Fukuda Metal Foil Powder Co., Ltd.), BHY-22B-T (manufactured by JX Nippon Oil & Metal Co., Ltd.), BHY-22B-HA (manufactured by JX Nippon Oil & Metal Co., Ltd.), BHYA-T (manufactured by JX Nippon Oil & Metal Co., Ltd.), BHYA-HA ( JX Nippon Steel Co., Ltd.), etc. These copper foils are easily available on the market.

By using the copper foil with the above-mentioned characteristics in the laminate of the present invention, a laminate with excellent adhesion between the metal layer and the resin layer, flexibility and folding resistance can be realized.

As a method of integrating the aforementioned three-layer film and the metal layer, a method of thermally pressing the metal layer and the three-layer film can be suitably used. For example, a commonly used pressing machine can be used for heat pressing at 200-350°C and a pressure of 3-10 MPa and holding for 10 minutes to 60 minutes.

The liquid crystal polymer laminate of the present invention obtained in this way, due to its excellent characteristics such as dimensional stability, low moisture absorption, etc., can be suitably used for semiconductor packages or motherboards obtained by the build-up method that has attracted attention in recent years. Multilayer printed circuit boards, flexible printed circuit boards, tape-automated bonding films, etc. are used.

<Printed Circuit Board>

The sixth aspect of the present invention is a printed circuit board using the aforementioned three-layer film as an insulating layer. The printed circuit board of the present invention may have the same structure as a known printed circuit board, except that the aforementioned three-layer film is used as an insulating layer, and can be manufactured in the same way. That is, the printed circuit board includes an insulating layer containing three-layer films and a circuit pattern on the three-layer film. In other words, the printed circuit board contains at least one three An insulating layer of a thin film and a circuit pattern formed on at least one of the first surface and the second surface of the insulating layer. The insulating layer can be composed of one three-layer film, or a plurality of three-layer films can be laminated. The circuit pattern may be located only on the first surface, or the first circuit pattern may be located on the first surface and the second circuit pattern may be located on the second surface.

The printed circuit board of the present invention can be fabricated by, for example, a metal layer provided on one or both sides of an insulating layer formed by one of the foregoing three-layer films, or an insulating layer formed by laminating a plurality of the foregoing three-layer films. The laminate is formed by etching the metal layer of the laminate to form a specific circuit pattern, and is directly manufactured with the laminate with the circuit pattern formed, or by laminating two or more sheets as required. The printed circuit board of the present invention preferably has a metal layer laminated on both sides of a three-layer film. In other words, the printed circuit board preferably includes a three-layer film, a first circuit pattern on the first surface of the three-layer film, and a second circuit pattern on the second surface of the three-layer film.

In the case of laminating a plurality of insulating layers of the aforementioned three-layer film, the plurality of three-layer films may be all the same, only a part may be the same, or all of them may be different. In addition, the number of pieces is not particularly limited as long as it is two or more pieces. Such an insulating layer can be integrated by, for example, stacking a plurality of three-layer films in the thickness direction, heating and pressing them to fuse them together.

The material of the metal layer is preferably an alloy containing copper, aluminum, silver, or one or more metals selected from these. Among them, copper or copper alloys are particularly preferred from the viewpoint of having better electrical conductivity. In addition, the metal layer is preferably formed of metal foil, and more preferably formed of copper foil, from the viewpoints of easy material handling, simple formation, and excellent economic efficiency. will When the metal layers are provided on both sides of the insulating layer, the materials of these metal layers can be the same or different.

The thickness of the metal layer is preferably 1 to 50 μm, more preferably 3 to 35 μm, and still more preferably 5 to 20 μm.

Here, the thickness of the metal layer is an average value obtained by measuring the thickness with a contact thickness meter at any 5 locations of the metal layer. In addition, when measuring the thickness of the metal layer, it is difficult to directly apply the contact thickness meter. It is also possible to measure the overall thickness in the same way as the above in the state where three layers of films are superimposed. It is calculated by the difference of the thickness of the layer (measured by the same method as above).

The method of providing the metal layer can exemplify the method of fusing the metal foil to the surface of the insulating layer, the method of bonding the metal foil to the surface of the insulating layer with an adhesive, and the method of plating the surface of the insulating layer by plating, screen printing or sputtering. Method, the method of coating with metal powder or metal particles.

When the insulating layer is formed by laminating a plurality of the aforementioned three-layer films, these three-layer films can be arranged overlapping in the thickness direction on the surface of the three-layer film located on one or both of the outermost sides, and further Overlap the metal foils, and heat and press these metal foils and a plurality of three-layer films, and when forming the insulating layer, a metal layer is also provided on one or both sides of the insulating layer at the same time.

The circuit pattern is formed by patterning the metal layer. As a method of forming a circuit pattern, etching or the like can be exemplified. The etching (processing) will be briefly described. First, perform the shielding of the metal layer in such a way that the metal layer becomes a specific circuit pattern. The part of the metal layer that is not shielded can be implemented by removing the latter part of the metal layer by an etching process called a wet method (medicament treatment). The agent used in the etching process includes, for example, an aqueous solution of iron (III) chloride. In addition, as the mask, it is sufficient to use a commercially available etching resist or dry film.

Then, from the masked metal layer part, the etching resist or dry film is removed with acetone or sodium hydroxide aqueous solution. By patterning the metal layer in this way, a specific circuit pattern (wiring) can be formed.

[Example]

Hereinafter, examples are used to describe the present invention more specifically, but the present invention is not limited by the examples.

<Manufacturing Example 1>

In a reactor equipped with a stirring device, a torque meter, a nitrogen introduction tube, a thermometer, and a reflux cooler, 677.4 g (3.6 mol) of 2-hydroxy-6-naphthoic acid (hereinafter referred to as "HNA"), 4- Hydroxyacetaniline (hereinafter referred to as "APAP") 332.6 g (2.2 mol), isophthalic acid (hereinafter referred to as "IPA") 99.7 g (0.6 mol), diphenyl ether-4,4'- 413.2 g (1.6 mol) of dicarboxylic acid (hereinafter referred to as "DEDA") and 673.8 g (6.6 mol) of acetic anhydride.

After fully replacing the inside of the reactor with nitrogen, the temperature was raised to 150°C in 15 minutes under a nitrogen stream, and the temperature was kept at reflux for 3 hours.

After that, while distilling out by-product acetic acid and unreacted acetic anhydride It was distilled off, and the temperature was raised to 320° C. in 170 minutes. The time when the torque increase was observed was regarded as the end of the reaction, and the contents were taken out. The obtained solid content was cooled to room temperature, pulverized with a coarse pulverizer, and observed with a polarizing microscope (ECLIPSE LV100POV manufactured by NIKON) to confirm that the schlieren pattern specific to the liquid crystal phase was displayed at 230°C. Further, the powdered liquid crystal polymer was maintained at 250° C. for 3 hours in a nitrogen environment, and the polymerization reaction was carried out in the solid phase. 100 g of the obtained liquid crystal polymer powder was added to 900 g of N-methyl-2-pyrrolidone, and heated to 120° C. for complete dissolution to obtain a brown transparent liquid crystal polymer solution composition (1).

<Manufacturing Example 2>

In a reactor equipped with a stirring device, a torque meter, a nitrogen inlet pipe, a thermometer, and a reflux cooler, 332.6 g (2.2 mol) of 4-hydroxyacetaniline (hereinafter referred to as "APAP"), isophthalic acid are fed (Hereinafter referred to as "IPA") 99.7g (0.6 mol), diphenyl ether-4,4'-dicarboxylic acid (hereinafter referred to as "DEDA") 413.2g (1.6 mol), and acetic anhydride 269.5 (2.6 Mol). After fully replacing the inside of the reactor with nitrogen, the temperature was raised to 150°C in 15 minutes under a nitrogen stream, and the temperature was kept at reflux for 3 hours.

After that, while distilling off the distilled byproduct acetic acid and unreacted acetic anhydride, the temperature was raised to 320°C in 170 minutes. The time when the torque increase was observed was regarded as the end of the reaction, and the contents were taken out. The solid content obtained was cooled to room temperature, and after being pulverized with a coarse pulverizer, the temperature was raised from room temperature to 400°C and observation with a polarizing microscope, but the schlieren pattern peculiar to the liquid crystal phase could not be observed.

[Example 1]

A film applicator (coating thickness 100μm) was used to apply the liquid crystal polymer solution composition (1) on one side of a commercially available polyimide resin film with a film thickness of 25μm Kapton H (manufactured by Toray DuPont), Heat with a hot air dryer at 100°C to remove the solvent, repeat the operation on the other side, heat treatment with a high temperature hot air dryer at 300°C to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=10μm /25μm/10μm).

The three-layer film obtained above was used as an insulating layer, and copper foil (“BHY-22B-T” (thickness 18μm, Rz=0.7μm) manufactured by JX Nippon Oil & Metal Co., Ltd. was laminated on both sides of the film. It is integrated with a high-temperature vacuum press machine ("KVHC-PRESS" manufactured by Kitagawa Seiki Co., Ltd., 300mm in length and 300mm in width) at a temperature of 340°C and a pressure of 5MPa for 20 minutes. Obtain a copper-clad laminate on both sides.

The double-sided copper-clad laminate obtained above was measured by TDR, and a printed circuit board was fabricated so as to become 50Ω. As a result, a circuit pattern with a wiring layer with a ground layer having a wiring width of 110 μm and a length of 100 mm was formed.

<Measurement of Transmission Loss>

For printed circuit patterns formed with circuit patterns, use the measuring probe "E8363B" manufactured by Agilent Technologies to measure transmission Loss (S21 parameter). Before and after immersion in water at 23°C for 48 hours, the transmission loss at frequencies of 5 GHz, 10 GHz, 20 GHz, and 40 GHz was measured.

The transmission losses at 5 GHz, 10 GHz, 20 GHz, and 40 GHz before immersion in water are shown in Tables 3 and 4. In addition, the rate of change of transmission loss (frequency 5GHz) before and after immersion at 23°C×48h is shown in Tables 3 and 4.

<Dimensional stability evaluation>

Using iron (III) chloride solution (manufactured by Kida Co., 40°Bome), the copper foil is completely removed from the double-sided copper-clad laminate. According to JIS C6481 "Testing methods for copper-clad laminates for printed wiring boards", thermomechanical is used An analysis device ("Thermo plus TMA8310" manufactured by Rigaku Corporation), while applying a load of 2.5 g to a test piece (insulating layer) of 20 mm × 50 mm, and measuring the inside surface when the temperature is raised to 250°C at 5°C/min under a nitrogen flow The coefficient of thermal expansion (temperature range 50~250℃: 1St scan). The results are shown in Tables 1 and 2.

[Example 2]

Except that the coating thickness of the film applicator was changed to 200μm in Example 1 to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=20μm/25μm/20μm), the same operation was performed. Production of copper clad laminates. The obtained copper clad laminate was measured by TDR, and a printed circuit board was produced so as to be 50 Ω. As a result, the wiring width was 142 μm and the length was 100 mm.

[Example 3]

Except for using a commercially available polyimide resin film with a film thickness of 25 μm U-PILEX S (manufactured by Ube Industries Co., Ltd.) in Example 1, the same operation was performed to produce a copper-clad laminate. The obtained copper clad laminate was measured by TDR, and a printed circuit board was produced so as to become 50 Ω. As a result, the wiring width was 110 μm and the length was 100 mm.

[Example 4]

Except for laminating copper foil ("F2-WS" (thickness 18 μm, Rz=2.1 μm) manufactured by Furukawa Electric Co., Ltd.) in Example 1, the same operation was performed to produce a copper-clad laminate. The obtained copper clad laminate was measured by TDR, and a printed circuit board was produced so as to be 50 Ω. As a result, the wiring width was 110 μm and the length was 100 mm.

[Example 5]

Except that the coating thickness of the film applicator was changed to 250μm in Example 1 to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=25μm/25μm/25μm), the same operation was performed. Production of copper clad laminates.

[Example 6]

Except that in Example 1, the coating thickness of the film applicator was changed to 335μm to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer Except for the object = 33.5μm/25μm/33.5μm), the same operation was performed to produce a copper-clad laminate.

[Comparative Example 1]

Except that the coating thickness of the film applicator was changed to 50μm in Example 1 to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=5μm/25μm/5μm), the same operation was performed, Production of copper clad laminates. The obtained copper-clad laminate was measured by TDR and a printed circuit board was produced so as to be 50 Ω. As a result, the wiring width was 95 μm and the length was 100 mm. It is known that the change in transmission loss before and after water immersion is as large as 23%.

[Comparative Example 2]

TDR measurement was performed using a copper-clad laminate Espanex-MB (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., polyimide film thickness: 50μm) using a commercially available polyimide resin film, and a printed circuit board was produced so that it became 50Ω As a result, the wiring width became 110 μm and the length became 100 mm.

Next, for the model sample, the measurement probe "E8363B" manufactured by Agilent Technologies was used to measure the transmission loss of the printed circuit board (S21 parameter).

It is known that the change in transmission loss before and after water immersion is as large as 35%.

[Comparative Example 3]

In the copper foil (JX Nippon Steel Nippon Steel Co., Ltd.) production of ``BHY-22B- T" (thickness 18μm, Rz=0.7μm)) was used to coat the liquid crystal polymer solution composition (1) on one side with a film applicator (coat thickness 500μm), and heated at 100°C using a hot air dryer to remove the solvent. The high-temperature hot-air dryer heat-processed at 300°C to obtain a single-sided copper-clad laminate (50 μm).

A copper foil is further laminated on the liquid crystal polymer of the single-sided copper clad laminate obtained above ("BHY-22B-T" (thickness 18μm, Rz=0.7μm) manufactured by JX Nippon Oil & Metal Co., Ltd.) , By using a high-temperature vacuum press machine ("KVHC-PRESS" manufactured by Kitagawa Seiki Co., Ltd., 300mm in length and 300mm in width), it is integrated by hot pressing at a temperature of 340℃ and a pressure of 5MPa for 20 minutes to obtain Copper clad laminate on both sides.

Using iron (III) chloride solution (manufactured by Kida Co., 40° Bomei), the copper foil is completely removed from the double-sided copper-clad laminate. According to JIS C6481 "Testing methods for copper-clad laminates for printed wiring", thermomechanical analysis is used Device ("Thermo plus TMA8310" manufactured by Rigaku Corporation), while applying a load of 2.5 g to a test piece (insulating layer) of 20 mm × 50 mm, and measuring the in-plane temperature at 5°C/min when heated to 250°C under a nitrogen stream Coefficient of thermal expansion (temperature range 50~250℃, 1St scan). Compared with the three-layer film, it can be seen that it expands greatly and the size changes greatly.

[Comparative Example 4]

A commercially available liquid crystal polymer film (Bextor 50μm manufactured by Kuraray) was used as an insulating layer, and copper foil (“BHY-22B-T” (thickness 18μm, 18μm, thickness 18μm, manufactured by JX Nippon Oil & Metal Co., Ltd.) was laminated on both sides of the copper foil. Rz=0.7μm)). It is integrated with a high-temperature vacuum press machine ("KVHC-PRESS" manufactured by Kitagawa Seiki Co., Ltd., 300mm in length and 300mm in width) at a temperature of 340°C and a pressure of 5MPa for 20 minutes. Obtain a copper-clad laminate on both sides.

Using iron (III) chloride solution (manufactured by Kida Co., 40° Bomei), the copper foil is completely removed from the double-sided copper-clad laminate. According to JIS C6481 "Testing methods for copper-clad laminates for printed wiring", thermomechanical analysis is used Device ("Thermo plus TMA8310" manufactured by Rigaku Corporation), while applying a load of 2.5 g to a test piece (insulating layer) of 20 mm × 50 mm, and measuring the in-plane temperature at a temperature of 5 °C/min to 250 °C under a nitrogen flow Coefficient of thermal expansion (temperature range 50~250℃, 1St scan). Compared with the three-layer film, it can be seen that the shrinkage is large and the size change is large.

As shown in the above results, the double-sided copper-clad laminates of Examples 1 to 4 using the three-layer film of the present invention are compared with the double-sided copper-clad laminates of Comparative Example 1. The change in transmission loss before and after water immersion The rate is low, and the dimensional stability is also good.

Moreover, even when the liquid crystal polymer layer is made thick as in Examples 5 to 6, the ruler Inch stability is also good. In the three-layer film of Examples 5-6, the liquid crystal polymer layer is thick. Therefore, when the three-layer film of Examples 5-6 is used to make a printed circuit board, the change rate of the transmission loss of the printed circuit board can be fully utilized, and Examples 1 to 4 have the same or lower effect than the modification.

Furthermore, in Comparative Examples 3 to 4, compared with the three-layer film of the present invention, the dimensional change is large, so the transmission loss measurement was not performed.

As described above, in the examples of this specification, a three-layer film is produced by coating a liquid composition containing a solvent and a liquid crystal polymer on a polyimide resin film. In addition to this method, the three-layer film can also be manufactured in the following <Method for manufacturing three-layer film by impregnation> or <Method for manufacturing three-layer film by sequential coating>. The three-layer film manufactured by this method is The three-layer film produced in the above-mentioned embodiment exerts the same effect.

<Method of manufacturing three-layer film by impregnation>

A commercially available polyimide resin film Kapton 200H (manufactured by Toray DuPont; 50μm) was immersed in the liquid crystal polymer solution composition (1) at room temperature for 1 minute and then pulled up to remove excessive liquid crystals attached to the surface After the polymer passes through a pair of rollers, the solvent is evaporated by a hot air dryer, and further, a high temperature hot air dryer is used for heat treatment to produce a three-layer film.

At this time, the film thickness of the liquid crystal polymer can also be adjusted by adjusting the pulling up speed.

<Method of manufacturing three-layer film by sequential coating>

As a support, a liquid crystal polymer solution composition (1), a polyamide resin liquid composition, and a liquid crystal polymer solution composition (1) were sequentially coated on a SUS foil, and heated at 100°C using a hot air dryer The solvent is removed, followed by heat treatment at 330°C, and a three-layer film can be produced by peeling from the support.

〔Industrial availability〕

According to the present invention, it is possible to provide a three-layer film with excellent dimensional stability and electrical characteristics when used in a laminate for a printed wiring board, and a method for manufacturing the three-layer film.

20‧‧‧Three-layer film

21‧‧‧Polyimide resin film

22a, 22b‧‧‧Liquid crystal polymer layer

Claims (14)

A three-layer film, which is on both sides of a polyimide resin film, is laminated with a liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen, and the thickness (T1) of the polyimide resin film is the same as the above The thickness (T2) of the liquid crystal polymer layer in which the hydroxycarboxylic acid is the mesogenic group satisfies the following relational formulas (a) and (b) (However, the two T2 systems are independent of each other and can be the same or different ), (a) 20 μ m≦T1≦50 μ m (b) 0.3≦T2/T1≦0.8. The three-layer film of claim 1, wherein the aforementioned liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen group contains structural units derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid. The three-layer film of claim 1 or 2, wherein, further, the liquid crystal polymer layer using hydroxycarboxylic acid as the mesogen group contains the following structural units (1) and (2), (1)-CO-Ar ¹ -CO- (2)-X-Ar ² -Y- (wherein Ar ¹ and Ar ² are independently represented by phenylene, naphthylene, biphenylene or represented by the following formula (3) Group; X and Y each independently represent an oxygen atom or an imino group; ^{the hydrogen atom in the aforementioned group represented by Ar 1} or Ar ² may be independently substituted with a halogen atom, an alkyl group, or an aryl group); 3) -Ar ³ -Z-Ar ^4- (Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group; Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group). A laminated board using a three-layer film as in any one of claims 1 to 3 as an insulating layer, and a metal layer is formed on at least one side of the insulating layer. Such as the laminate of claim 4, wherein the maximum height (Rz) of the aforementioned metal layer is 0.5~2.5μm. The laminate of claim 4, wherein the aforementioned metal layer contains copper. The laminate of claim 5, wherein the aforementioned metal layer contains copper. A printed circuit board using a laminate as claimed in claim 4. A printed circuit board using a laminate as claimed in claim 5. A printed circuit board using a laminate as claimed in claim 6. A printed circuit board using a laminate as claimed in claim 7. A method for manufacturing a three-layer film, which includes coating a liquid composition containing a solvent and a liquid crystal polymer on both sides of a polyimide resin film, and coating the polyimide resin film with the liquid composition A method for producing a three-layer film including the coating step of the liquid composition on both sides, the solvent removal step of removing the solvent in the liquid composition, and the heat treatment step. The liquid crystal polymer contains 2-hydroxyl The structural unit of benzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units, (1)-CO-Ar ¹ -CO- (2)-X-Ar ² -Y- (where, Ar ¹ and Ar ² is each independently a phenylene, naphthylene, biphenylene or a group represented by the following formula (3); X and Y are each independently an oxygen atom or an imino group; Ar ¹ , or Ar ^{The hydrogen atom in the aforementioned group represented by 2} may be independently substituted by a halogen atom, an alkyl group or an aryl group); (3)-Ar ³ -Z-Ar ^4- (Ar ³ and Ar ⁴ are each independently represented Phenylene or naphthylene; Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group), and in the liquid composition coating step, the coating amount of the liquid composition is adjusted , So that the thickness of the polyimide resin film (T1) and the thickness of the liquid crystal polymer layer (T2) satisfy the following relational expressions (a) and (b), (a) 20 μm ≦T1≦50 μm (b) 0.3≦T2/T1≦0.8 (However, the two T2 systems are independent of each other and can be the same or different). A method for manufacturing a three-layer film, which comprises impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer, and impregnating both sides of the polyimide resin film with the liquid composition Step, the solvent removal step of removing the solvent in the liquid composition, and the heat treatment step of the three-layer film manufacturing method, wherein the liquid crystal polymer contains 2-hydroxybenzoic acid or 2-hydroxy-6 -The structural unit of naphthoic acid, and the following structural units (1) and (2), (1)-CO-Ar ¹ -CO- (2)-X-Ar ² -Y- (where, Ar ¹ and Ar ² series each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (3); X and Y each independently represent an oxygen atom or an imino group; Ar ¹ , or Ar ² The hydrogen atoms in the aforementioned groups may be independently substituted by halogen atoms, alkyl groups or aryl groups); (3)-Ar ³ -Z-Ar ^4- (Ar ³ and Ar ⁴ are each independently representing a Phenyl or naphthylene; Z represents an oxygen atom, sulfur atom, carbonyl group, sulfonyl group or alkylene group), and in the impregnation step, the liquid composition in the polyimide resin film is adjusted The adhesion amount is such that the thickness (T1) of the aforementioned polyimide resin film and the thickness (T2) of the liquid crystal polymer layer satisfy the following relational expressions (a) and (b), (a) 20 μm ≦T1≦50 μ m (b) 0.3≦T2/T1≦0.8 (However, the two T2 systems are independent of each other and can be the same or different). A method for manufacturing a three-layer film, which includes the steps of preparing a liquid composition containing a solvent and a liquid crystal polymer, and a polyimide resin liquid composition that is a precursor of the polyimide resin; on a support The step of sequentially coating the aforementioned liquid composition, the aforementioned polyamide resin liquid composition, and the aforementioned liquid composition into three layers; the solvent removal step of removing the solvent in the aforementioned three-layer liquid composition ; A method of manufacturing a three-layer film with a three-layer film forming step, wherein as the aforementioned liquid crystal polymer, the system contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural unit (1 ) And (2), (1)-CO-Ar ¹ -CO- (2)-X-Ar ² -Y- (where Ar ¹ and Ar ² are independently phenylene, naphthylene, Biphenylene or a group represented by the following formula (3); X and Y each independently represent an oxygen atom or an imino group; the hydrogen atom in the aforementioned group represented by ^{Ar 1} or Ar ^{2 may also be independently} Substituted by a halogen atom, an alkyl group or an aryl group); (3)-Ar ³ -Z-Ar ^4- (Ar ³ and Ar ⁴ each independently represent a phenylene group or a naphthylene group; Z represents an oxygen atom, sulfur Atom, carbonyl group, sulfonyl group or alkylene group), and in the aforementioned coating step, the coating amount of the aforementioned liquid composition containing the solvent and the liquid crystal polymer is adjusted so that the thickness of the aforementioned polyimide resin film ( T1) and the thickness of the liquid crystal polymer layer (T2) satisfy the following relational expressions (a) and (b), (a) 20 μ m≦T1≦50 μ m (b) 0.3≦T2/T1≦0.8 (but , The two T2 systems are independent of each other and can be the same or different).

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