TWI783049B - Polyimide film and metal-clad laminate - Google Patents

Abstract

The present invention provides a kind of having high dimensional accuracy and dimensional stability, thereby suppressing Produced polyimide films and metal-clad laminates with curls and wrinkles after microfabrication. A kind of polyimide film, comprises the polyimide layer of monolayer or multi-layer, and satisfies: (i) thickness is in the range of 3 μ m～10 μ m; (ii) in thickness direction, with a polyimide film The birefringence (△na) at a point 1.0±0.2 μm in the direction of the central part based on a plane, and the birefringence (△nb ) difference (△na-△nb) is ±0.015 or less; (iii) the sum of birefringence (△nc) at a point of ±0.2 μm based on △na and △nb and the central part in the thickness direction The difference between the average value (Δnv) of (Δna+Δnb+Δnc) is ±0.015 or less in any of Δna and Δnb; (iv) The coefficient of thermal expansion (CTE) is 15 ppm/K or less; (v ) in-plane birefringence (Δn) is 0.01 or less.

Description

Polyimide film and metal-clad laminate

The present invention relates to a polyimide film and a metal-clad laminate, and more particularly to a polyimide film and a metal-clad laminate that can be suitably used for components and auxiliary materials of electronic components.

In recent years, metal-clad laminates composed of polyimide and its composition and metal foil have been used in flexible printed circuit boards (Flexible Printed Circuits, FPC) used in various electronic devices, flexible solar cells, and negative electrodes of lithium-ion batteries. It has been extensively researched in materials, suspensions of hard disk drives, materials of Liquid Crystal Display (LCD), components of organic electroluminescent (EL) displays, auxiliary materials, etc., and is used in various applications. Adoption is expanding.

In addition, with the development of miniaturization, weight reduction, and space saving of electronic equipment, metal-clad laminates are required to be thin and lightweight, or finely patterned with metal foil, in addition to the heat resistance and adhesiveness that are currently required. , micro-processability of polyimide, higher dimensional stability, etc.

On the other hand, polyimide films have excellent characteristics in heat resistance, cold resistance, chemical resistance, electrical insulation, mechanical strength, etc., and thus are widely used in various field. In particular, it is widely used as a base film for manufacturing FPCs, carrier tapes for tape automated bonding (TAB), etc., by utilizing the characteristics of excellent heat resistance and high rigidity. For example, in TAB applications and chip-on-flex (COF) applications, high-density patterning and alignment accuracy when mounting semiconductors are required.

Patent Document 1 proposes a polyimide film in which the degree of surface alignment of the front and back surfaces is controlled in order to suppress the occurrence of curl due to heating.

In addition, high-density wiring and multi-layer FPC have been developed due to progress in mounting technology, and along with this, high bending resistance is also required. Thinning of polyimide has been studied as one of effective means for improving the bending resistance and miniaturization of FPC.

Patent Document 2 proposes a method of thinning a polyimide film and controlling tear propagation resistance, ultrasonic propagation speed, and elongation on one side in order to suppress cracking or wrinkling.

In addition, the present applicant obtained the knowledge that a polyimide film excellent in dimensional stability can be obtained by controlling the in-plane retardation (retardation) of the polyimide film, and filed an application in advance (Japanese Patent Application No. 2016-089514) .

[Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-201632

[Patent Document 2] Japanese Patent Laid-Open No. 2014-196467

The object of the present invention is to provide a polyimide film that has high dimensional accuracy and dimensional stability that cannot be solved in the polyimide films of Patent Document 1 and Patent Document 2, and further suppresses the occurrence of curling or wrinkles after microfabrication. Imide film and metal-clad laminate.

The inventors of the present invention have paid attention to the fact that curling or wrinkles after microfabrication are caused by the poor physical properties of molecules in the thickness direction of the polyimide film, and found that by controlling the polyimide film especially in the thickness direction The distribution of molecular alignment in a specific region can suppress the amount of curling and ensure high dimensional stability, thereby completing the present invention.

That is, the polyimide film of the present invention comprises the polyimide layer of monolayer or multilayer, and described polyimide film is characterized in that satisfying following condition (i)～condition (v):

(i) The thickness is within the range of 3 μm to 10 μm.

(ii) In the thickness direction, the birefringence (Δna) at a point of 1.0±0.2 μm in the direction of the central portion based on one surface of the polyimide film, and the central portion based on the other surface The difference (Δna-Δnb) in the birefringence (Δnb) at a point of 1.0±0.2 μm in the direction is ±0.015 or less.

(iii) The average value of the sum (Δna+Δnb+Δnc) of the birefringence (Δnc) at the point of ±0.2 μm from the central part in the thickness direction of the above-mentioned Δna and the above-mentioned Δnb The difference of (Δnv) is ±0.015 or less in either of the above-mentioned Δna and Δnb.

(iv) Coefficient of Thermal Expansion (CTE) 15ppm/K or less.

(v) In-plane birefringence (Δn) is 0.01 or less.

The polyimide film of the present invention may be that the polyimide layer contains polyimide containing tetracarboxylic acid residues and diamine residues, and contains 50 mol% or more of diamine residues derived from a diamine compound represented by the following general formula (A1).

In the formula (A1), the linking group _X0 represents a single bond, and Y independently represents a monovalent hydrocarbon group with 1 to 3 carbons, or an alkoxy group with 1 to 3 carbons, or a carbon A perfluoroalkyl or alkenyl group having a number of 1 to 3, n ₁ represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4.

The metal-clad laminate of the present invention includes an insulating layer and a metal layer on at least one surface of the insulating layer, and the metal-clad laminate is characterized in that the insulating layer includes the polyimide film.

The polyimide film and the metal-clad laminate of the present invention have excellent dimensional accuracy and dimensional stability, and further suppress the occurrence of curling or wrinkles after microfabrication. Therefore, the polyimide film and metal-clad laminate of the present invention are used, for example, in flexible printed circuit boards (FPC), flexible solar cells, negative electrode materials for lithium-ion batteries, and hard disk drives. It is useful in a wide range of applications such as suspensions of devices, materials of LCDs, components of organic EL displays, and auxiliary materials, and contributes to improving the reliability of electronic equipment and electrical products using these components or materials.

Next, embodiments of the present invention will be described.

Polyimide membrane

The polyimide film according to one embodiment of the present invention is a polyimide film including a polyimide layer of a single layer or a multilayer, and satisfies the following conditions (i) to (v).

(i) The thickness is in the range of 3 μm to 10 μm.

The polyimide film of this embodiment has a thickness in the range of 3 μm to 10 μm, preferably in the range of 3 μm to 7 μm, more preferably 4 μm, for the purpose of low rigidity of the film or formation of microfabrication on the polyimide. The range of ~6μm is suitable. If the thickness of the polyimide film of this embodiment is less than 3 μm, the film may be broken during processing, and if it exceeds 10 μm, CTE control becomes difficult and the film tends to curl.

(ii) In the thickness direction, the birefringence (Δna) at a point of 1.0±0.2 μm in the direction of the central portion based on one surface of the polyimide film, and the central portion based on the other surface The difference (Δna-Δnb) in the birefringence (Δnb) at a point of 1.0±0.2 μm in the direction is ±0.015 or less.

In order to control film curl, the polyimide film according to this embodiment preferably has a birefringence difference (Δna-Δnb) in the thickness direction of ±0.015 or less, preferably ±0.01 or less. like When the birefringence difference (Δna-Δnb) in the thickness direction exceeds ±0.015, the curl of the film becomes large, and handling during processing becomes difficult. In addition, when a metal pattern is formed on a film, a difference in dimensional accuracy tends to occur between the upper surface and the lower surface of the film.

(iii) The average value of the sum (Δna+Δnb+Δnc) of the birefringence (Δnc) at the point of ±0.2 μm from the central part in the thickness direction of the above-mentioned Δna and the above-mentioned Δnb The difference of (Δnv) is ±0.015 or less in either of the above-mentioned Δna and Δnb.

In any one of Δna and Δnb of the polyimide film of this embodiment, the difference from the average value (Δnv) of the sum of the birefringence in the thickness direction (Δna+Δnb+Δnc) is within ±0.015 Less than, preferably less than ±0.01.

In this embodiment, if the difference between any one of Δna and Δnb of the polyimide film and the average value (Δnv) of the total birefringence in the thickness direction (Δna+Δnb+Δnc) exceeds ±0.015, when a through hole (through hole) is formed on the polyimide film, cracks tend to easily occur due to poor alignment.

(iv) The coefficient of thermal expansion (CTE) is 15 ppm/K or less.

The CTE of the polyimide film of this embodiment is preferably 15 ppm/K or less, preferably in the range of -5 ppm/K to 10 ppm/K, more preferably in the range of -3 ppm/K to 5 ppm/K.

When the CTE of the polyimide film of this embodiment exceeds 15 ppm/K, misalignment tends to occur between the electronic component and the metal film formed on the film by applying heat when mounting the electronic component. In addition, when polyimide is formed on a metal with a CTE of 15ppm/K or less, there may be problems due to the difference in CTE between the metal layer and the polyimide layer. Tendency to generate internal stress easily.

(v) In-plane birefringence (Δn) is 0.01 or less.

The in-plane birefringence (Δn) of the polyimide film of this embodiment is preferably 0.01 or less, preferably 0.005 or less, more preferably 0.003 or less.

If the in-plane birefringence (Δn) of the polyimide film of the present embodiment exceeds 0.01, there is a tendency that the length (Machine Direction, MD) direction and the width (lateral direction (Machine Direction, MD)) direction of the polyimide film tend to be different. Transverse Direction, TD)) Dimensional change during heating in the direction tends to be poor, and when forming a metal pattern on polyimide or performing microfabrication of polyimide, the processed pattern is prone to deviation.

<Form of polyimide>

The polyimide film of this embodiment is not particularly limited as long as it satisfies the conditions (i) to (v) as described above, and may be a film (sheet), or may be laminated on copper foil, glass plate, polyimide film, etc. A film in the state of being on a substrate such as a resin sheet such as an imide film, a polyamide film, or a polyester film.

<filler>

The polyimide film of this embodiment may contain an inorganic filler as needed. Specifically, examples thereof include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and the like. These can be used alone or in combination of two or more.

<Polyimide>

The polyimide film of this embodiment has a polyimide layer containing polyimide, and the polyimide constituting the polyimide layer is obtained by reacting tetracarboxylic dianhydride and diamine. It is obtained by imidizing polyamide acid. Therefore, in the polyimide film of the present embodiment, the polyimide constituting the polyimide layer includes a tetracarboxylic acid residue derived from tetracarboxylic dianhydride and a diamine residue derived from diamine. . Moreover, in this invention, a tetracarboxylic-acid residue shows the tetravalent group derived from tetracarboxylic dianhydride, and a diamine residue shows the dimethyl group derived from a diamine compound.

Hereinafter, specific examples of polyimides used in the present embodiment will be understood by describing acid anhydrides and diamines.

The tetracarboxylic acid residues contained in polyimide are preferably exemplified by: 3,3',4,4'-biphenyl tetracarboxylic dianhydride Tetracarboxylic dianhydride, s-BPDA), 2,2',3,3'-biphenyl tetracarboxylic dianhydride (2,2',3,3'-biphenyl tetracarboxylic dianhydride, i-BPDA), etc. acid residues. Among them, tetracarboxylic acid residues derived from s-BPDA (hereinafter also referred to as s-BPDA residues) tend to form ordered structures, and can reduce the in-plane birefringence (Δn) in high temperature environments. The amount of change is therefore especially preferred. In addition, although the s-BPDA residue can impart self-supporting properties to the gel film of polyamic acid which is a precursor of polyimide, it tends to increase the CTE after imidization. From this point of view, the s-BPDA residue is preferably in the range of 10 mol % to 70 mol %, more preferably 10 mol %, relative to all the tetracarboxylic acid residues contained in polyimide. It is suitable to be within the range of mol%~50 mol%.

Tetracarboxylic acid residues other than the s-BPDA residue contained in polyimide can be preferably enumerated: tetracarboxylic acid residues derived from pyromellitic dianhydride (pyromellitic dianhydride, PMDA) ( Hereinafter also referred to as PMDA residues). The PMDA residue is preferably 30 mol % ~ 90 mol with respect to all tetracarboxylic acid residues contained in polyimide %, more preferably within the range of 50 mol% to 90 mol%. The PMDA residue is optional, but it is a residue that functions to control the thermal expansion coefficient and control the glass transition temperature.

Other tetracarboxylic acid residues include, for example, tetracarboxylic acid residues derived from the following aromatic tetracarboxylic dianhydrides: 3,3',4,4'-diphenylenetetracarboxylic dianhydride, 4, 4'-oxydiphthalic anhydride, 2,3',3,4'-biphenyl tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 2 ,3,3',4'-benzophenone tetracarboxylic dianhydride or 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-di Phenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3",4,4"-p-terphenyl tetracarboxylic dianhydride, 2,3,3", 4"-terphenyltetracarboxylic dianhydride or 2,2",3,3"-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-propane dianhydride or 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride or bis(3,4-dicarboxyphenyl)methane dianhydride , bis(2,3-dicarboxyphenyl) anhydride or bis(3,4-dicarboxyphenyl) anhydride, 1,1-bis(2,3-dicarboxyphenyl)ethanedianhydride Or 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,2,7,8-phenanthrene-tetracarboxylic dianhydride, 1,2,6,7-phenanthrene-tetracarboxylic acid Dianhydride or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl) tetra Fluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2 ,3,6,7-naphthalene tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid di anhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3, 6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride or 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2, 3,8,9-perylene-tetracarboxylic dianhydride, 3,4,9,10-perylene-tetracarboxylic dianhydride, 4,5,10,11-perylene-tetracarboxylic dianhydride or 5,6, 11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine -2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4, 4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, etc.

In the polyimide film of the present embodiment, the diamine residue contained in the polyimide preferably includes, for example, a diamine residue derived from a diamine compound represented by the following general formula (A1). .

In the formula (A1), the linking group _X0 represents a single bond, and Y independently represents a monovalent hydrocarbon group with 1 to 3 carbons, or an alkoxy group with 1 to 3 carbons, which may be substituted by a halogen atom or a phenyl group, or a perfluoroalkyl group or alkenyl group having 1 to 3 carbon atoms, n ₁ 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 formula (A1), a plurality of substituents Y, integer p, and integer q may be the same or different.

Since the diamine residue derived from the diamine compound represented by general formula (A1) has a rigid structure, it can express low CTE. From this point of view, the diamine residue represented by the general formula (A1) is preferably 50 mol % or more, more preferably 60 mol %, relative to all the diamine residues contained in polyimide. mol% or more, more preferably within the range of 60 mol% to 100 mol%.

Moreover, the diamine residue derived from the diamine compound represented by general formula (A1), for example, the diamine residue represented by following general formula (1) is mentioned preferably.

In the formula (1), R ₁ and R ₂ independently represent an alkyl group with 1 to 3 carbons that may be substituted by a halogen atom or a phenyl group, or a perfluoroalkyl group with 1 to 3 carbons, or a perfluoroalkyl group with 1 to 3 carbons. ~3 alkoxy, or alkenyl with 2~3 carbons.

The diamine residue represented by the general formula (1) tends to form an ordered structure, and can advantageously suppress the amount of change in the in-plane birefringence (Δn) especially in a high-temperature environment. From this point of view, the diamine residue represented by the general formula (1) is preferably 50 mol % or more, more preferably 60 mol %, relative to all the diamine residues contained in polyimide. Mole% or more, and more preferably within the range of 60 mol% to 90 mol%.

Preferred specific examples of the diamine residue represented by the general formula (1) include diamine residues derived from the following diamine compounds: 2,2'-dimethyl-4,4'-diamino Biphenyl (2,2'-dimethyl-4,4'-diaminobiphenyl, m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl (2,2'-diethyl-4, 4'-diaminobiphenyl, m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (2,2'-diethoxy-4,4'-diaminobiphenyl, m-EOB), 2 ,2'-dipropoxy-4,4'-diaminobiphenyl (2,2'-dipropoxy-4,4'-diaminobiphenyl, m-POB), 2,2'-n-propyl-4,4 '-Diaminobiphenyl (2,2'-n-propyl-4,4'-diaminobiphenyl, m-NPB), 2,2'-divinyl-4,4'-diaminobiphenyl (2,2 '-divinyl-4,4'-diaminobiphenyl, VAB), 4,4'-diamino Biphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, TFMB) and the like. Among these diamine compounds, especially 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) is easy to form an ordered structure, which can reduce the in-plane birefringence (△ n) is therefore particularly preferred.

In addition, in this specification, regarding a "diamine compound", the hydrogen atoms in the two terminal amino groups may be substituted, for example, -NR ₃ R ₄ (here, R ₃ and R ₄ independently represent any arbitrary group such as an alkyl group). substituent).

In addition, in order to improve elongation and bending resistance when made into a polyimide film, it is preferable that the polyimide contains a compound selected from the following general formula (2) to general formula (4). At least one diamine residue in the group consisting of the indicated diamine residues.

In the formula ( ₂ ), _R5 and R6 independently represent a halogen atom, or an alkyl or alkoxy group or an alkenyl group with 1 to 4 carbon atoms that may be substituted by a halogen atom, and X independently represents a group selected from -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CO-, -COO-, -SO ₂ -, -NH- or -NHCO- In the divalent group, m and n independently represent an integer of 0-4.

[chemical 5]

In the formula (3), R ₅ , R ₆ and R ₇ independently represent a halogen atom, or an alkyl or alkoxy group or an alkenyl group with 1 to 4 carbon atoms that may be substituted by a halogen atom, and X independently means selected from -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CO-, -COO-, -SO ₂ -, -NH- or In the divalent group in -NHCO-, m, n, and o independently represent an integer of 0-4.

In the formula (4), R ₅ , R ₆ , R ₇ and R ₈ each independently represent a halogen atom, or an alkyl or alkoxy group with 1 to 4 carbons that may be substituted by a halogen atom, or an alkenyl group, X ₁ and X ₂ each independently represent a single bond selected from -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CO-, -COO Divalent groups in -, -SO ₂ -, -NH- or -NHCO-, except when both X ₁ and X ₂ are single bonds, m, n, o and p independently represent 0~4 integer.

In addition, the so-called "independently" means that in one of the formulas (2) to (4), or in the formulas (2) to (4), a plurality of linking groups X, linking groups X ₁ , Linking group X ₂ , multiple substituents R ₅ , substituent R ₆ , substituent R ₇ , substituent R ₈ , and integer m, integer n, integer o, and integer p may be the same or different.

The diamine residues represented by general formula (2)~general formula (4) have curved Because of this, it is possible to impart flexibility to the polyimide film. Here, since the diamine residues represented by the general formula (3) and the general formula (4) have three or four benzene rings, in order to suppress an increase in the coefficient of thermal expansion (CTE), it is preferable to bind to The terminal group of the benzene ring is at the para position. In addition, from the viewpoint of imparting flexibility to the polyimide film and suppressing an increase in the coefficient of thermal expansion (CTE), the total amount of diamine residues represented by general formula (2) to general formula (4) is relatively All the diamine residues contained in the polyimide are preferably in the range of 10 mol % to 50 mol %, more preferably in the range of 10 mol % to 30 mol %. When the total amount of the diamine residues represented by general formula (2) to general formula (4) is less than 10 mol %, the elongation in the case of forming a film decreases, resulting in a decrease in bending resistance and the like. On the other hand, if it exceeds 50 mol%, the alignment of molecules will decrease, making it difficult to lower the CTE.

In the general _formula ( ₂ ), preferred examples of the base R and the base R can include: a hydrogen atom or an alkyl group with 1 to 4 carbons that can be substituted by a halogen atom, or an alkoxy group with 1 to 3 carbons , or alkenyl. In addition, in the general formula (2), preferred examples of the linking group X include -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -SO ₂ -, or -CO-. Preferred specific examples of the diamine residue represented by the general formula (2) include diamine residues derived from the following diamine compounds: 4,4'-diaminodiphenyl ether (4,4' -diamino diphenyl ether, 4,4'-DAPE), 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3 ,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 3,4 '-Diaminodiphenylpropane, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4, 4'-diaminodiphenylphenone, 3,3'-diaminodiphenylphenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3' - Diaminobenzophenone and the like.

In the general formula (3), preferred examples of the base R ₅ , the base R ₆ and the base R ₇ include: a hydrogen atom or an alkyl group with 1 to 4 carbons that may be substituted by a halogen atom, or an alkyl group with 1 to 3 carbons Alkoxy, or alkenyl. In addition, in the general formula (3), preferred examples of the linking group X include -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, -SO ₂ -, or -CO-. Preferred specific examples of the diamine residue represented by the general formula (3) include diamine residues derived from the following diamine compounds: 1,3-bis(4-aminophenoxy)benzene (1 ,3-bis(4-aminophenoxy)benzene, TPE-R), 1,4-bis(4-aminophenoxy)benzene (1,4-bis(4-aminophenoxy)benzene, TPE-Q), bis( 4-aminophenoxy)-2,5-di-tert-butylbenzene (bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, DTBAB), 4,4-bis(4-amino Phenoxy)benzophenone (4,4-bis(4-aminophenoxy)benzophenone, BAPK), 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4 - bis[2-(4-aminophenyl)-2-propyl]benzene and the like.

In the general formula (4), preferred examples of the group R ₅ , R ₆ , R ₇ and R ₈ include: a hydrogen atom or an alkyl group with 1 to 4 carbons that may be substituted by a halogen atom, or a carbon Alkoxy or alkenyl with a number of 1 to 3. In addition, in the general formula (4), preferred examples of the linking group X ₁ and the linking group X ₂ include: single bond, -O-, -S-, -CH ₂ -, -CH(CH ₃ )-, _-SO2- or -CO-. However, the case where _both the linking group X1 and the linking group X2 are single bonds is excluded from the viewpoint of imparting _a bending site. Preferred specific examples of the diamine residue represented by the general formula (4) include diamine residues derived from the following diamine compounds: 4,4'-bis(4-aminophenoxy)biphenyl (4,4'-bis(4-aminophenoxy)biphenyl, BAPB), 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis[4 -(4-aminophenoxy)phenyl]ether (2,2'-bis[4-(4-aminophenoxy)phenyl]ether, BAPE), bis[4-(4-aminophenoxy)phenyl] Qi and so on.

Other diamine residues include, for example, diamine residues derived from the following aromatic diamine compounds: 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[4- (3-aminophenoxy)phenyl]biphenyl, 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] terpene, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4 -(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4 ,4'-methylenedi-2,6-xylaniline, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3, 3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3"-diamino-p-terphenyl, 4,4'-[1,4-phenylene bis(1-methyl ethylene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylene)]bisaniline, bis(p-aminocyclohexyl)methane, bis(p-β- Amino-tert-butylphenyl) ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1- Dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis(β-amino-tert-butyl)toluene, 2,4-bis Aminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-di Aminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, etc.

In polyimide, by selecting the types of the tetracarboxylic acid residues and diamine residues, or the respective molar ratios when two or more kinds of tetracarboxylic acid residues or diamine residues are used, it is possible to Control thermal expansion coefficient, storage elastic coefficient, tensile elastic coefficient, etc. In addition, in the case of non-thermoplastic polyimide having a plurality of structural units of polyimide, it can exist in the form of blocks or randomly, from suppressing the in-plane birefringence (Δn) From the viewpoint of deviation, it is preferable to exist randomly.

<Manufacturing method of polyimide film>

The mode of the manufacturing method of the polyimide film of this embodiment includes, for example: [1] Coating and drying a solution of polyamic acid on a support substrate, followed by imidization to manufacture a polyimide film Method; [2] After coating a solution of polyamic acid on a support substrate and drying it, the gel film of polyamic acid is peeled off from the support substrate, and imidized to manufacture a polyimide film method. In addition, since the polyimide film of the present embodiment is a polyimide film comprising a multilayer polyimide layer, examples of its production method include: A method (casting method) of applying and drying a solution of amine acid, and performing imidization; The method of imidization (multi-layer extrusion method), etc.

The method [1] may include, for example, the following steps 1a to 1c: (1a) coating a solution of polyamide acid on a support substrate and drying it; (1b) applying a solution of polyamide acid to a support substrate A step of heat-treating amine acid to imidize, thereby forming a polyimide layer; and (1c) separating the support substrate from the polyimide layer, thereby obtaining a polyimide membrane.

The method [2] may include, for example, the following steps 2a to 2c: (2a) a step of coating a solution of polyamic acid on a support substrate and drying it; (2b) a step of separating the support substrate from the gel film of polyamide acid; A step of obtaining a polyimide film by heat-treating the acid gel film to imidize it.

The method [3] is to repeat step 1a or step 2a multiple times in the method [1] or method [2] to form a laminated structure of polyamic acid on the supporting substrate. In addition, it can be It is carried out in the same manner as the above-mentioned method [1] or method [2].

In the method [4], in the step 1a of the method [1] or the step 2a of the method [2], the polyamic acid laminated structure is simultaneously coated and dried by multilayer extrusion, and It can be carried out in the same manner as the above [1] method or [2] method.

The polyimide film produced in the present invention preferably completes imidization of polyamic acid on a support substrate. Since the imidization is performed with the polyamic acid resin layer fixed on the supporting substrate, the stretching and contraction of the polyimide layer during imidization can be suppressed and the polyimide can be maintained. Film thickness or dimensional accuracy.

In addition, the in-plane birefringence (Δn) can also be controlled by separating the gel film of polyamic acid on the support substrate, stretching the gel film of polyamide acid uniaxially or biaxially Elongation, imidization is carried out simultaneously or sequentially. At this time, in order to control Δn more precisely, it is preferable to appropriately adjust conditions such as the temperature rise rate during the stretching operation and imidization, the completion temperature of imidization, and the load.

<Synthesis of polyimide>

Generally, polyimides can be produced by combining tetracarboxylic dianhydride with diamine The compound reacts in a solvent to generate polyamic acid, and then heats up to close the ring. For example, a tetracarboxylic dianhydride and a diamine compound are dissolved in an organic solvent in an approximately equimolar manner, stirred at a temperature in the range of 0° C. to 100° C. for 30 minutes to 24 hours to perform a polymerization reaction, thereby obtaining the Polyamide acid, the precursor of polyimide. During the reaction, the reaction components are dissolved so that the produced precursor is within the range of 5% by weight to 30% by weight, preferably within the range of 10% by weight to 20% by weight, in the organic solvent. Examples of organic solvents used in the polymerization reaction include: N,N-dimethylformamide (N,N-dimethyl formamide, DMF), N,N-dimethylacetamide (N,N-dimethyl acetamide , DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP), 2-butanone, dimethylsulfoxide (DMSO ), hexamethylphosphamide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triethylene glycol dimethyl Ether (triglyme), cresol, etc. These solvents can also be used in combination of two or more kinds, and further aromatic hydrocarbons such as xylene and toluene can also be used in combination. In addition, the usage amount of such an organic solvent is not particularly limited, and it is preferable to adjust the usage amount so that the concentration of the polyamic acid solution obtained by the polymerization reaction becomes about 5% by weight to 30% by weight.

The synthesized polyamic acid is usually advantageously used in the form of a reaction solvent solution, and can be concentrated, diluted or replaced with other organic solvents as necessary. In addition, polyamic acid is generally excellent in solvent solubility, and thus can be advantageously used. The viscosity of the solution of polyamide acid is preferably in the range of 500 cps to 100,000 cps. If it deviates from the above range, when the coating operation is performed with a coater or the like, uneven thickness is likely to occur in the film, Defects such as stripes. The method of imidizing polyamic acid is not particularly limited, and for example, heat treatment such as heating in the solvent at a temperature in the range of 80° C. to 400° C. for 1 hour to 24 hours is suitably used. In addition, it is preferable to perform the heat treatment at a temperature in the range of 120° C. to 160° C. for more than 30 seconds, and it is more preferable to perform the heat treatment for more than 30 seconds to 10 minutes or less. When the heat treatment time at a temperature in the range of 120° C. to 160° C. is 30 seconds or less, poor alignment in the thickness direction tends to occur, and it becomes difficult to lower the CTE.

<Metal-clad laminate>

The material of the metal layer in the metal-clad laminate of this embodiment is not particularly limited, and examples thereof include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, and titanium. , lead, magnesium, manganese, and their alloys. Among these, aluminum, iron, nickel, stainless steel, and alloys thereof are preferable from the viewpoint of low thermal expansion.

The thickness of the metal layer is not particularly limited. For example, when aluminum is used as the metal layer, it is preferably 100 μm or less, more preferably within a range of 10 μm to 50 μm. From the viewpoint of production stability and operability, it is preferable to set the lower limit of the thickness of the metal layer to 5 μm.

In the metal-clad laminate according to this embodiment, in order to improve the adhesiveness between the polyimide film and the metal layer, the surface of the polyimide film may be subjected to a modification treatment such as plasma treatment, for example. In addition, for the layer in contact with the metal layer in the polyimide film, for example, a thermoplastic polyimide layer may be laminated. The metal-clad laminate of this embodiment may be a single-sided metal-clad laminate or a double-sided metal-clad laminate.

Regarding the metal-clad laminate of this embodiment, for example, a resin film including the polyimide film of this embodiment may be prepared, and a seed layer may be formed by sputtering metal thereon, and then, for example, copper plating may be performed. to form a copper layer.

In addition, the metal-clad laminate can also be produced by preparing a resin film including the polyimide film of the present embodiment and laminating a metal foil thereon by thermocompression bonding or the like.

Example

Examples are shown below to describe the features of the present invention more specifically. However, the scope of the present invention is not limited to the Examples. In addition, in the following examples, unless otherwise specified, various measurements and evaluations were performed by the following methods.

Determination of viscosity

Regarding the measurement of the viscosity, the viscosity at 25° C. was measured using an E-type viscometer (trade name: DV-II+Pro manufactured by Brookfield). Set the rotation speed so that the torque (torque) becomes 10% to 90%, and read the value when the viscosity is stable after 2 minutes from the start of the measurement.

Determination of Warpage

After conditioning the polyimide film with a size of 50 mm×50 mm at 23° C. and 50% relative humidity (RH) for 24 hours, the direction of curling was defined as the upper surface, and set on a smooth table. The curl amount at this time was measured using a vernier caliper. At this time, the case where the film curled toward the substrate etching side was described as plus (plus), and the case where the film curled toward the opposite side was described as minus (minus), and the average value of the measured values at the four corners of the film was defined as the amount of curl.

Measurement of in-plane retardation (RO) and in-plane birefringence (△n)

Using a birefringence meter (trade name: wide range birefringence evaluation system WPA-100 manufactured by Photonic-Lattice, measurement area: MD: 200 mm × TD: 150 mm), a predetermined sample is determined The retardation in the in-plane direction of . In addition, the incident angle was 0°, and the measurement wavelength was 543 nm.

In addition, the value obtained by dividing the measured value of in-plane retardation (RO) by the thickness of the sample for evaluation was referred to as "in-plane birefringence (Δn)".

Retardation in thickness direction and measurement of birefringence

For the polyimide layer, thin film slices with a thickness of 0.5 μm were produced by the ultramicrotomy method, and retardation in the thickness direction was measured. At this time, a birefringence meter (trade name: Birefringence Distribution Observation Camera for Microscope Mounting PI-Micro, manufactured by Photonic-Lattice Co., Ltd.) was used. In addition, the measurement wavelength was 520 nm, and the incident angle was 0°.

ReA is the value of the retardation at a point of 1.0±0.2 μm in the direction of the center based on one surface of the polyimide layer (film).

ReB is the value of the retardation at a point of 1.0±0.2 μm in the direction of the central portion based on the other surface of the polyimide layer (film).

Rev is the sum (ReA+ReB+ReC) of ReA, ReB, and the retardation value (ReC) at a point of ±0.2 μm based on the central part of the polyimide layer (film) in the thickness direction. average value.

In addition, the value obtained by dividing ReA by the thickness (0.5 μm) of the film slice was defined as “birefringence (Δna)”, and the value obtained by dividing ReB by the thickness (0.5 μm) of the film slice was The obtained value was referred to as "birefringence (Δnb)", and the value obtained by dividing ReC by the thickness (0.5 μm) of the film slice was referred to as "birefringence (Δnc)".

Δnv is the average value of the total (Δna+Δnb+Δnc) of Δna, Δnb, and Δnc.

Determination of Coefficient of Thermal Expansion (CTE)

Using a thermomechanical analyzer (Thermal Mechanical Analyzer, TMA: device name TMA/SS6100) device, a 5.0g load is applied to a polyimide layer with a size of 3mm×15mm on one side, and a certain heating rate (10°C/min) is applied on one side. Tensile tests were performed by heating and cooling in the temperature range from 30°C to 280°C, and the coefficient of thermal expansion (ppm/ K).

Calculation of imide group concentration

The imide group concentration refers to the molecular weight of the imide group (-(CO) ₂ -N-) in the polyimide obtained by heat-treating and imidizing polyamide acid divided by the molecular weight of the polyamide The value obtained from the molecular weight of the imine structure as a whole.

Determination of Peel Strength

Using a Tensilon tester (trade name: Strograph VE-1D manufactured by Toyo Seiki Seisakusho Co., Ltd.), the resin side of the measurement sample was fixed on an aluminum plate with double-sided tape, and the metal foil faced The 90° direction was peeled at a speed of 50 mm/min, and the median strength when the metal foil was peeled from the resin layer by 10 mm was obtained.

The abbreviations used in Examples and Comparative Examples represent the following compounds.

PMDA: pyromellitic dianhydride

s-BPDA: 3,3',4,4'-Biphenyltetracarboxylic dianhydride

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

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

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

DMAc: N,N-Dimethylacetamide

(Synthesis Example 1)

Under nitrogen flow, 30.390 g of m-TB (0.1432 moles) and 5.978 g of TPE-R (0.0205 moles) and DMAc in an amount of 15% by weight after polymerization were charged into the reaction tank, and Stir at room temperature to dissolve. Then, after adding 24.480g of PMDA (0.1122 mol) and 14.152g of s-BPDA (0.0481 mol), continue to stir at room temperature for 3 hours and carry out polymerization reaction, prepare polyamic acid solution 1 (imide base concentration of 32.8% by weight). The solution viscosity of polyamide acid solution 1 is 18,400 cps.

(Synthesis Example 2)

Under nitrogen flow, 38.979 g of BAPP (0.0950 mol) and DMAc in an amount to have a solid concentration after polymerization of 12% by weight were charged into the reaction tank, and stirred and dissolved at room temperature. Next, after adding 21.022 g of PMDA (0.0964 mol), stirring was continued at room temperature for 3 hours to perform a polymerization reaction to prepare a polyamic acid solution 2 (imide group concentration: 23.6% by weight). The solution viscosity of polyamide acid solution 2 is 28,500 cps.

Example 1

On one side of an Invar foil with a thickness of 100 μm, the cured thickness After the polyamic acid solution 1 was uniformly applied so that the thickness became about 6 μm, it was heated and dried at 120° C. to remove the solvent. Furthermore, a heat treatment from 120°C to 160°C was performed for 60 minutes, and further, a stepwise heat treatment was performed from 160°C to 360°C within 60 minutes to complete the imidization, and the metal-clad laminate 1 was prepared.

For the prepared metal-clad laminate 1 , the invar foil was etched away using an aqueous solution of ferric chloride to prepare a polyimide film 1 (thickness: 6.3 μm). The physical properties of the polyimide film 1 are as follows.

CTE: -1.1ppm/K, curl amount: no occurrence (0mm), peel strength: >1.0kN/m, |ReA-ReB|: 0.6nm, |Rev-ReA|: 0.3nm, |Rev-ReB|: 0.1nm, in-plane retardation: 6nm, |△na-△nb|: 1.2×10 ^-3 , |△nv-△na|: 0.6×10 ^-3 , |△nv-△nb|: 0.2×10 ^-3 , In-plane birefringence: 0.95×10 ^-3 .

Example 2

A metal-clad laminate 2 was produced in the same manner as in Example 1, except that the heat treatment was performed from 120° C. to 160° C. for 10 minutes.

The prepared metal-clad laminate 2 was etched and removed using an aqueous ferric chloride solution in the same manner as in Example 1 to prepare a polyimide film 2 (thickness: 6.1 μm). The physical properties of the polyimide film 2 are as follows.

CTE: 2.0ppm/K, curl amount: 0.9mm, peel strength: >1.0kN/m, |ReA-ReB|: 3.6nm, |Rev-ReA|: 3.4nm, |Rev-ReB|: 0.2nm, surface Internal retardation: 8nm, |△na-△nb｜: 7.2×10 ^-3 , |△nv-△na｜: 6.8×10 ^-3 , |△nv-△nb｜: 0.4×10 ^-3 , in-plane double Refractive index: 1.31×10 ^-3 .

<Preparation of Circuit Board>

A dry film is laminated on the surface of the Invar foil of the metal-clad laminate 2, a dry film resist is patterned, and the Invar foil is etched along the pattern to form an Invar circuit to prepare a circuit Substrate 2'.

A Ni—Cr alloy (Cr: 20% by weight) was formed to a thickness of 20 nm on the surface of the circuit board 2 ′ opposite to the circuit formation side using a sputtering device, and a copper thin film layer with a thickness of 200 nm was formed on the surface. Then, a photoresist layer was formed on the copper thin film layer, and selective exposure and development were performed on the photoresist layer to obtain a wiring pattern with a pitch of 20 μm. Using this as a plating mask, form copper wiring with a thickness of 12 μm on the seed layer by electroplating, remove the photoresist layer, and remove the copper thin film layer and Ni-Cr alloy layer with a flush etching solution , whereby the circuit substrate 2 is prepared.

<Integrated Circuit (IC) Chip Mounting>

At 400° C., the IC chip was mounted on the copper wiring side of the circuit board 2 by the bonding process for 0.5 seconds, and there was no misalignment between the copper wiring and the IC chip, and no defect occurred.

Example 3

A metal-clad laminate 3 was prepared in the same manner as in Example 1 except that heat treatment was performed from 120° C. to 160° C. for 1 minute and 30 seconds.

The prepared metal-clad laminate 3 was etched and removed in the same manner as in Example 1 using an aqueous ferric chloride solution to prepare a polyimide film 3 (thickness: 6.4 μm). The physical properties of the polyimide film 3 are as follows.

CTE: 2.3ppm/K, curl amount: .2.3mm, peel strength: >1.0kN/m, |ReA-ReB|: 4.5nm, |Rev-ReA|: 0.6nm, |Rev-ReB|: 3.9nm, In-plane retardation: 9nm, |△na-△nb|: 9×10 ^-3 , |△nv-△na|: 1.2×10 ^-3 , |△nv-△nb|: 7.8×10 ^-3 , in-plane Birefringence: 1.41×10 ^-3 .

Example 4

After the polyamic acid solution 2 was uniformly coated on one side of an invar foil having a thickness of 100 μm so that the thickness after curing was about 0.5 μm, it was heated and dried at 120° C. to remove the solvent. Next, the polyamic acid solution 1 was uniformly applied thereon so that the thickness after curing was about 5.5 μm, and the solvent was removed by heating and drying at 120° C. Furthermore, a heat treatment from 120°C to 160°C was performed for 60 minutes, and further, a stepwise heat treatment was performed from 160°C to 360°C within 60 minutes to complete the imidization and prepare the metal-clad laminate 4 .

The prepared metal-clad laminate 4 was etched and removed using an aqueous solution of ferric chloride to prepare a polyimide film 4 (thickness: 6.2 μm). The physical properties of the polyimide film 4 are as follows.

CTE: 3.6ppm/K, curl amount: 4.9mm, peel strength: >1.0kN/m, |ReA-ReB|: 0.8nm, |Rev-ReA|: 0.2nm, |Rev-ReB|: 0.2nm, surface Internal retardation: 8nm, |△na-△nb｜: 1.6×10 ^-3 , |△nv-△na｜: 0.4×10 ^-3 , |△nv-△nb｜: 0.4×10 ^-3 , in-plane double Refractive index: 1.29×10 ^-3 .

(comparative example 1)

A metal-clad laminate 5 was produced in the same manner as in Example 1 except that heat treatment was performed from 120° C. to 160° C. for 30 seconds.

For the prepared metal-clad laminate 5, the Invar foil was etched and removed using an aqueous solution of ferric chloride in the same manner as in Example 1 to prepare a polyimide film 5 (thickness: 6.1 μm). The physical properties of the polyimide film 5 are as follows.

CTE: 3.1ppm/K, curl amount: 4.6mm, |ReA-ReB|: 8.4nm, |Rev-ReA|: 2.4nm, |Rev-ReB|: 6.0nm, in-plane retardation: 7nm, |△na- △nb|: 16.8×10 ^-3 , |△nv-△na|: 4.8×10 ^-3 , |△nv-△nb|: 12×10 ^-3 , in-plane birefringence: 1.15×10 ^-3 .

(comparative example 2)

For metal-clad laminate 5, a circuit board was prepared in the same manner as in "Preparation of circuit board" in Example 2, and an IC chip was mounted on the copper wiring side of the prepared circuit board by bonding at 400°C for 0.5 seconds. , as a result, an offset occurs between the copper wiring and the IC wafer.

Table 1 shows the measured locations for the measurement of retardation in the thickness direction of the polyimide layer in Examples 1 to 4 and Comparative Example 1.

As mentioned above, although the embodiment of this invention was described in detail for the purpose of illustration, this invention is not limited by the said embodiment.

Claims (3)

A kind of polyimide film, it is characterized in that, comprises the polyimide layer of monolayer or multilayer, and satisfies following condition i ~ condition v: condition i: thickness is in the scope of 3 μ m ~ 10 μ m; condition ii: in thickness In the direction, the birefringence Δna at a point of 1.0±0.2 μm in the direction of the central part based on one surface of the polyimide film, and the birefringence Δna in the direction of 1.0±0.2 μm in the direction of the central part based on the other surface The difference of birefringence Δnb in the dots, that is, Δna-Δnb is ±0.015 or less; condition iii: any one of the above-mentioned Δna and Δnb and the above-mentioned Δna and the above-mentioned Δnb and Δnc The difference between the average value Δnv of the sum of Δna+Δnb+Δnc, where Δnc is the birefringence index at a point of ±0.2 μm based on the central part in the thickness direction, is ±0.015 or less; condition iv: coefficient of thermal expansion CTE is 15ppm/K or less; condition v: the in-plane birefringence △n is 0.01 or less, and the method of measuring the in-plane birefringence △n is as follows: use a birefringence meter to obtain the in-plane direction of a given sample Retardation, where the incident angle is 0°, the measurement wavelength is 543nm, and the value obtained by dividing the measured value of the in-plane retardation by the thickness of the sample for evaluation is the in-plane birefringence Δn, the birefringence Δna, The measurement methods of Δnb and Δnc are as follows: For the polyimide layer, a film slice with a thickness of 0.5 μm is prepared by the ultrathin section method, and the retardation in the thickness direction is measured. At this time, a birefringence meter is used, and , the measuring wavelength is 520nm, the incident angle is 0°, Among them, ReA is the value of the retardation at a point of 1.0±0.2 μm in the direction of the central portion based on one surface of the polyimide film, and ReB is the direction of the central portion based on the other surface of the polyimide film The value of the retardation at the point of 1.0±0.2 μm above, ReC is the value of the retardation at the point of ±0.2 μm based on the central part of the thickness direction of the polyimide film, and then, ReA is divided by the The value obtained at a thickness of 0.5 μm was taken as the birefringence Δna, the value obtained by dividing ReB by the thickness of the film slice of 0.5 μm was taken as the birefringence Δnb, and the value obtained by dividing ReC by the thickness of the film section of 0.5 μm was given as Birefringence Δnc. The polyimide film as described in item 1 of the scope of application for patents, wherein the polyimide layer comprises polyimide containing tetracarboxylic acid residues and diamine residues, and relative to the diamine The total amount of residues contains more than 50 mol% of diamine residues derived from diamine compounds represented by the following general formula A1,

In formula A1, the linking group _X0 represents a single bond, and Y independently represents a monovalent hydrocarbon group with 1 to 3 carbons, an alkoxy group with 1 to 3 carbons, an alkoxy group with 1 to 3 carbons, perfluoroalkyl or alkenyl, n ₁ represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4. A metal-clad laminate, comprising an insulating layer and a metal layer on at least one surface of the insulating layer, and the metal-clad laminate is characterized in that: the insulating layer includes the first or second item of the scope of the patent application The polyimide membrane described in item.