WO2009136557A1

WO2009136557A1 - Polyimide precursor, photosensitive polyimide precursor composition, photosensitive dry film, and flexible printed circuit board using those materials

Info

Publication number: WO2009136557A1
Application number: PCT/JP2009/058159
Authority: WO
Inventors: 久遠宮崎; 隆志早川; 明宏加藤; 秀明高橋
Original assignee: 旭化成イーマテリアルズ株式会社
Priority date: 2008-05-09
Filing date: 2009-04-24
Publication date: 2009-11-12
Also published as: CN102015835A; TWI384015B; TW201006867A; JP5603977B2; JP5417323B2; KR20100125467A; JPWO2009136557A1; KR101308811B1; JP2013241607A

Abstract

Disclosed is a polyimide precursor: which enables the production of such a photosensitive dry film that has no tackiness, causes no cracking in a photosensitive layer thereof when folded after removal of a solvent therefrom, and can achieve good lithography thereon; which can be applied to a FPC that causes less warpage after baking; and which can exhibit flame retardancy without the need of adding any halogen compound thereto. Also disclosed is a photosensitive polyimide precursor composition. Further disclosed is a photosensitive dry film. Still further disclosed is a flexible printed circuit board produced by using any one of the aforementioned materials. The polyimide precursor is characterized by comprising an acid dianhydride represented by general formula (1) [wherein X represents a bivalent organic group having a C_3-30 alkylene group; and R₁ represents a hydrogen atom, a C_1-10 univalent alkyl group, an alkoxy group or a halogen group].

Description

Polyimide precursor, photosensitive polyimide precursor composition, photosensitive dry film, and flexible printed wiring board using them

The present invention relates to a polyimide precursor, a photosensitive polyimide precursor composition, a photosensitive dry film, and a flexible printed wiring board using them.

In recent years, a film-like printed circuit board called a flexible printed circuit board (hereinafter also referred to as “FPC”) has gained popularity. This board has a coverlay made of polyimide film etc. on the processed FCCL (Flexible Copper Clad Laminate) and is mainly used for devices such as mobile phones, laptop computers, digital cameras, etc. It has been. Since FPC maintains its function even when it is bent, it is an indispensable material for reducing the size and weight of equipment. Particularly in recent years, electronic devices represented by notebook computers have been reduced in size and weight, and by adopting FPC for such products, the size and weight of the devices can be reduced, the product cost can be reduced, and the design can be reduced. Contributes to simplification.

The coverlay provided in this FPC is formed by bonding mainly using a polyimide film with an adhesive. However, with the miniaturization and thinning of the FPC, problems have arisen in the positional accuracy of bonding. In view of this, development of a photosensitive cover lay capable of finely processing only necessary portions with high precision by irradiating with an actinic ray such as ultraviolet rays has begun to be carried out energetically. Among them, the dry film type photosensitive coverlay exhibits excellent dimensional accuracy and does not require a solvent drying step. Therefore, in the FPC manufacturing, the process can be simplified and is expected as a material with low environmental load.

Among photosensitive cover lay materials, a photosensitive cover lay using a polyimide precursor is expected as an excellent cover lay from the viewpoint of bending resistance derived from polyimide, heat resistance, and electrical insulation. For example, Patent Document 1 discloses a heat-resistant adhesive using tetracarboxylic dianhydride and diamine. Patent Document 2 discloses a film-forming photosensitive heat-resistant resin composition using a polyimide precursor, and Patent Document 3 discloses a photosensitive cover coat material containing polyamic acid. Patent Document 4 discloses an adhesive film made of a specific acid dianhydride. However, in the case of a photosensitive cover lay using these polyimide precursors, the molecular weight of the polyimide precursor is lowered due to the tackiness problem of the photosensitive dry film and the solvent removal accompanying the formation of the photosensitive dry film, and the resulting photosensitive When the conductive dry film is bent, there may be a problem that the photosensitive layer is broken. Furthermore, when the pattern is formed by lithography due to a decrease in the molecular weight of the polyimide precursor, the development time is not stable in the development using an alkaline aqueous solution, the pattern film thickness becomes thin, and the pattern shape is distorted. Arise. Further, in the step of converting the polyimide precursor to the polyimide, the FPC may be warped due to the stress caused by the solvent removal or the ring closure reaction accompanying the imidization of the polyimide precursor. When warpage occurs in the FPC, problems such as poor adhesion between the FCCL and the coverlay and an increase in driving power of an electronic device equipped with the FPC arise. Therefore, it is required to improve the warpage of the FPC having a coverlay on the copper wiring.

In addition, the coverlay is required to exhibit flame retardancy in a flame retardancy test represented by the UL standard VTM test. For the purpose of expressing flame retardancy, halogen compounds have been originally added to coverlays. However, from the viewpoint of environmental protection and biotoxicity, it is desired that non-halogen and flame retardancy be expressed.

JP 2004-269622 A Japanese Patent Laid-Open No. 04-18450 JP 05-158237 A Japanese Patent Laid-Open No. 10-330723

The present invention has been made in view of the above points, and when used for FPC, a polyimide precursor, a photosensitive polyimide precursor composition, and a photosensitive dry film that have less bending of FPC after baking and excellent bendability. And it aims at providing the flexible printed wiring board using them.

The polyimide precursor of this invention is characterized by including the acid dianhydride represented by following General formula (1).

(X is a divalent organic group having an alkylene group having 3 to 30 carbon atoms. R ₁ represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. .)

The polyimide precursor of the present invention preferably contains a diamine represented by the following general formula (2).

(Y is a divalent organic group having an alkylene group having 2 to 20 carbon atoms. R ₂ represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. .)

In the polyimide precursor of this invention, it is preferable that the acid dianhydride represented by following General formula (3) is included.

(A represents an integer of 1 to 20. b represents an integer of 3 to 30. R ₃ represents a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)

In the polyimide precursor of this invention, it is preferable that the diamine represented by following General formula (4) is included.

(Z represents an alkylene group having 2 to 20 carbon atoms. R ₄ represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. C represents 2 to 30 carbon atoms. Represents an integer.)

(A represents an integer of 1 to 15. b represents an integer of 5 to 20. R ₃ represents a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)

In the polyimide precursor of the present invention, the diamine represented by the general formula (4) is preferably 25 mol% to 75 mol% of all diamine components.

The photosensitive polyimide precursor composition of the present invention contains 100 parts by mass of the polyimide precursor and 5 to 30 parts by mass of a photosensitizer.

In the photosensitive polyimide precursor composition of the present invention, the photosensitive agent preferably contains a quinonediazide structure.

The photosensitive polyimide precursor composition of the present invention preferably contains a compound having a phenolic hydroxyl group as a dissolution inhibitor.

The photosensitive dry film of the present invention is characterized in that the above photosensitive polyimide precursor composition is applied to a support film, desolvated, and then a cover film is laminated.

The flexible printed wiring board of the present invention is formed using the photosensitive dry film.

In the polyimide precursor of the present invention, the ratio (Mw2 / Mw1) between the weight average molecular weight (Mw1) in the varnish and the weight average molecular weight (Mw2) after desolvation at 120 ° C. or lower is 0.7 or more. It is characterized by that.

The photosensitive polyimide precursor composition of the present invention uses a polyimide precursor obtained from an acid dianhydride having a specific structure, so that when used for FPC, there is little warping of the FPC after baking and bending. There is an effect that it is excellent in properties.

Hereinafter, the present invention will be specifically described.
(A) Polyimide precursor An acid dianhydride and diamine are used as a monomer of a polyimide precursor. It is known that the molecular weight of the polyimide precursor is reduced by solvent removal with heating. From the viewpoint of reducing the decrease in molecular weight, the acid dianhydride used for the polyimide precursor is represented by the following general formula (1). The acid dianhydride represented is used. Any acid-free dihydrate represented by the structure may be used alone or in combination of two or more. By suppressing the decrease in molecular weight in the solvent removal step, it is possible to prevent cracking during folding when the photosensitive dry film is formed, and to improve the folding property.

Among these, it is preferable to use an acid dianhydride represented by the following general formula (3) from the viewpoint of suppressing a decrease in molecular weight in the solvent removal step.

Among the acid dianhydrides represented by the general formula (3), a is preferably 1 to 15, and b is preferably 5 to 20. Specifically, butanediol-bis-trimellitic anhydride ester, pentanediol-bis-trimellitic anhydride ester, heptanediol-bis-trimellitic anhydride ester, decanediol-bis-trimellitic anhydride ester, Examples thereof include sundiol-bis-trimellitic anhydride ester, polypropylenediol-bis-trimellitic anhydride ester, polytetramethylenediol-bis-trimellitic anhydride ester, and the like. These compounds may be used alone or in combination of two or more.

In addition to the above acid dianhydrides, other acid dianhydrides may be used for the polyimide precursor according to the present invention. Specifically, as the aromatic tetracarboxylic acid, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetra Carboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3 '-Benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1, 1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride , Screw (2,3-di Carboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 3,3′-oxydiphthalic dianhydride, 4,4′-oxydiphthalic dianhydride, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylic acid-1,4-phenylene ester, 4- (2,5-dioxotetrahydrofuran- 3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,2-bis (3 -Dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) phenyl) hexafluoropropane dianhydride, 2,2-bis (4- (3,4) -Dicarboxybenzoyloxy) phenyl) hexafluoropropane dianhydride, 2,2'-bis (trifluoromethyl) -4,4'-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, ethylenediol- And bis-trimellitic anhydride ester.

Aliphatic tetracarboxylic dianhydrides include cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5,6-cyclohexanetetracarboxylic dianhydride 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene- Examples include 2,3,5,6 tetracarboxylic dianhydride and 1,2,3,4-butanetetracarboxylic dianhydride. These acid dianhydrides are preferably used in the range of 0 mol% to 50 mol% with respect to the total amount of acid dianhydride of the polyimide precursor from the viewpoint of reducing warpage after baking.

The diamine used for the polyimide precursor is represented by the following general formula (2) from the viewpoint of suppressing a decrease in molecular weight in the solvent removal step and from the viewpoint of improving tackiness when a photosensitive dry film is obtained after the solvent removal. It is preferable to use diamines. Any diamine represented by the structure may be used alone or in combination of two or more. In the following general formula (2), R ₂ is preferably a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.

Specifically, dimethylene-bis (2-aminobenzoate), dimethylene-bis (3-aminobenzoate), dimethylene-bis (4-aminobenzoate), trimethylene-bis (2-aminobenzoate), trimethylene-bis (3 -Aminobenzoate), trimethylene-bis (4-aminobenzoate), tetramethylene-bis (2-aminobenzoate), tetramethylene-bis (3-aminobenzoate), tetramethylene-bis (4-aminobenzoate), 3- Methyltetramethylene-bis (2-aminobenzoate), 3-methyltetramethylene-bis (3-aminobenzoate), 3-methyltetramethylene-bis (4-aminobenzoate), pentamethylene-bis (2-aminobenzoate) , Pentamethylene (3-aminobenzoate), pentamethylene-bis (4-aminobenzoate), decamethylene-bis (2-aminobenzoate), decamethylene-bis (3-aminobenzoate), decamethylene-bis (4-aminobenzoate), etc. Can be mentioned. These diamines may be used alone or in combination of two or more.

Furthermore, among them, the viewpoint of using the compound represented by the following general formula (4) to suppress a decrease in molecular weight in the solvent removal step, and the viewpoint of improving tackiness when a photosensitive dry film is obtained after the solvent removal. Therefore, it is preferable.

Specifically, polydimethylene oxide-di-o-aminobenzoate), polydimethylene oxide-di-m-aminobenzoate, polydimethylene oxide-di-p-aminobenzoate, polytrimethylene oxide-di-o-aminobenzoate Polytrimethylene oxide-di-m-aminobenzoate, polytrimethylene oxide-di-p-aminobenzoate, polytetramethylene oxide-di-o-aminobenzoate, polytetramethylene oxide-di-m-aminobenzoate, poly Tetramethylene oxide-di-p-aminobenzoate, poly-3-methyltetramethylene oxide-di-o-aminobenzoate, poly-3-methyltetramethylene oxide-di-m-aminobenzoate, poly-3-methyltetramethyle Oxide-di-p-aminobenzoate, polypentamethylene oxide-di-o-aminobenzoate, polypentamethylene oxide-di-m-aminobenzoate, polypentamethylene oxide-di-p-aminobenzoate, polydecamethylene oxide- Di-o-aminobenzoate, polydecamethylene oxide-di-m-aminobenzoate, polydecamethylene oxide-di-p-aminobenzoate, poly (tetramethylene / 3-methyltetramethylene ether) glycol bis (4-aminobenzoate) ) And the like. These diamines may be used alone or in combination of two or more.

Furthermore, the blending amount of these diamines is such that the diamine represented by the general formula (4) is 25 mol% to 75 mol% in the total diamine components from the viewpoint of reducing warpage after baking. preferable.

In particular, it is preferable to use the compound represented by the general formula (2) and the compound represented by the general formula (4) at the same time. When the compound represented by the general formula (2) and the compound represented by the general formula (4) are used at the same time, reduction of warping, improvement of tackiness when a photosensitive dry film is obtained after solvent removal, and From the viewpoint of good lithography properties, the compounding amount of the compound represented by the general formula (4) is preferably 25 mol% to 75 mol% with respect to the total amount of diamine.

Moreover, it is possible to use the diamine and other diamines simultaneously. Specifically, 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3 , 3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 3, , 7-Diamino-dimethylbenzothiophene-5,5-dioxide, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone, 4,4′-bis (4-aminophenyl) sulfide, 4,4′- Diaminodiphenyl sulfone, 4,4′-diaminobenzanilide, 1, n-bis (4-aminophenoxy) alkane, , 3-bis (4-aminophenoxy) -2,2-dimethylpropane, 1,2-bis [2- (4-aminophenoxy) ethoxy] ethane, 9,9-bis (4-aminophenyl) fluorene, 5 (6) -amino-1- (4-aminomethyl) -1,3,3-trimethylindane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 2,2-bis (4-amino) Phenoxyphenyl) propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- ( -Aminophenoxy) phenyl] hexafluoropropane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 4,6-dihydroxy-1,3-phenylenediamine, 3,3'-dihydroxy-4,4 ' -Diaminobiphenyl, 1,4-bis (4-aminophenoxy) pentane, 1,5-bis (4'-aminophenoxy) pentane, bis (γ-aminopropyl) tetramethyldisiloxane, 1,4-bis (γ -Aminopropyldimethylsilyl) benzene, bis (4-aminobutyl) tetramethyldisiloxane, bis (γ-aminopropyl) tetraphenyldisiloxane, diaminosiloxane compounds represented by the following general formula (5), and the like. These may be used alone or in combination of two or more. These diamines are preferably blended in an amount of 0 to 50 mol% with respect to the total number of moles of diamine, from the viewpoint of reducing warpage after baking.

When synthesizing the polyimide precursor, if necessary, the end of the polyamide precursor may be sealed with a monofunctional acid anhydride, monofunctional carboxylic acid, or monofunctional amine.

It is also possible to esterify a part of the carboxyl group of the polyimide precursor according to the present invention using known compounds and methods such as alcohol compounds.

The polyimide precursor according to the present invention can be made into a photosensitive polyimide precursor composition by blending (B) a photosensitive agent and (C) an organic solvent.

(B) Photosensitive agent The photosensitive polyimide precursor composition according to the present invention is blended with a compound that generates an acid when irradiated with actinic rays as a photosensitive agent. The photosensitizer is not particularly limited as long as it generates an acid upon irradiation with actinic rays, but is preferably a compound having a quinonediazide structure, such as a benzoquinonediazide compound or a naphthoquinonediazide compound. For example, those described in US Pat. No. 2,797,213 and US Pat. No. 3,669,658 can be used. Among these, ester compounds of a phenol compound and 1,2-naphthoquinone-2-diazide-4-sulfonic acid or 1,2-naphthoquinone-2-diazide-5-sulfonic acid are preferable. These may be used alone or in combination of two or more.

The blending amount of the photosensitizer according to the present invention is preferably 5 to 35 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the polyimide precursor. The blending amount of the photosensitizer is preferably 5 parts by mass or more from the viewpoint of developing photosensitivity and inhibiting dissolution in a developer composed of an alkaline aqueous solution, and 35 parts by mass or less from the viewpoint of developing sensitivity and cover toughness.

(C) Organic solvent Examples of the organic solvent used in the present invention include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, γ-butyrolactone, and dimethyl sulfoxide. Moreover, the solvent whose boiling point is lower than these solvents can be mix | blended as needed. By blending the low boiling point solvent, foaming during drying can be suppressed. Specific examples of the low boiling point solvent include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethyl alcohol, isopropyl alcohol, n-butanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and hexylene glycol. Alcohols, 1,4-dioxane, trioxane, diethyl acetal, 1,2-dioxolane, ethers such as diethylene glycol dimethyl ether, tetrahydrofuran, anisole, triethylene glycol dimethyl ether, ethyl acetate, methyl benzoate, ethylene glycol monomethyl ether acetate, ethylene Glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethyl Glycol diacetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol diacetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diacetate And esters such as n-heptane, n-octane, cyclohexane, benzene, toluene, xylene, ethylbenzene and diethylbenzene. The blending amount of the organic solvent is preferably 25 to 900 parts by mass, more preferably 100 to 400 parts by mass with respect to 100 parts by mass of the polyimide precursor. When the blending amount is more than 900 parts by mass, it becomes difficult to maintain the film thickness after coating, and when it is less than 25 parts by mass, the polyimide precursor is not completely dissolved.

(D) Dissolution inhibitor A dissolution inhibitor can be mix | blended with the photosensitive polyimide precursor composition which concerns on this invention as needed. By mix | blending a dissolution inhibitor, melt | dissolution to the developing solution which consists of an alkaline aqueous solution of a polyimide precursor can be suppressed. The dissolution inhibitor according to the present invention refers to a compound that hydrogen bonds with a carboxyl group or a phenolic hydroxyl group of a polyimide precursor. When the carboxyl group or phenolic hydroxyl group of the polyimide precursor is hydrogen-bonded with the dissolution inhibitor, the polyimide precursor is shielded from the developer, and coupled with the hydrophobicity of the compound, it is possible to inhibit the dissolution of the polyimide precursor.

Examples of the compound having a carboxyl group or a group capable of hydrogen bonding with a phenolic hydroxyl group include a carboxylic acid compound, a carboxylic acid ester compound, an amide compound, and a urea compound. From the viewpoints of the effect of inhibiting dissolution in a developer composed of an alkaline aqueous solution and the storage stability, a compound represented by the following general formula (6) is preferable, and an amide compound and a urea compound are more preferable.

(R ₅ and R ₆ represent an organic group consisting of all or part of a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom. R ₅ and R ₆ may be the same or different.)

Examples of the amide compound include N, N-diethylacetamide, N, N-diisopropylformamide, N, N-dimethylbutyramide, N, N-dibutylacetamide, N, N-dipropylacetamide, N, N-dibutylformamide N, N-diethylpropionamide, N, N-dimethylpropionamide, N, N′-dimethoxy-N, N′-dimethyloxamide, N-methyl-ε-caprolactam, 4-hydroxyphenylbenzamide, salicylamide, And salicylanilide, acetanilide, 2′-hydroxyacetanilide, 3′-hydroxyacetanilide, 4′-hydroxyacetanilide.

Among them, it has a phenolic hydroxyl group from the viewpoint of lowering the glass transition point of the photosensitive layer and the film obtained by baking the photosensitive layer, controlling the solubility in a developer composed of an alkaline aqueous solution, and increasing the residual film ratio. A compound is preferable, and an amide compound having a phenolic hydroxyl group is more preferable. Specific examples include 4-hydroxyphenylbenzamide, 2'-hydroxyacetanilide, 3'-hydroxyacetanilide, and 4'-hydroxyacetanilide. These may be used alone or in combination of two or more.

Examples of the urea compound include 1,3-dimethylurea, tetramethylurea, tetraethylurea, 1,3-diphenylurea, and 3-hydroxyphenylurea. Among them, it contains phenolic hydroxyl groups from the viewpoint of controlling the solubility in a developer composed of an aqueous alkali solution, increasing the residual film ratio, and lowering the glass transition point of the photosensitive layer and the film obtained by baking the photosensitive layer. More preferred are urea compounds. Specific examples include 3-hydroxyphenylurea. These may be used alone or in combination of two or more.

In the case of using an amide compound, the dissolution inhibitor according to the present invention may be blended in an amount of 0.1 mol to 2.0 mol with respect to 1 mol of the carboxyl group and phenolic hydroxyl group of the polyimide precursor from the viewpoint of expression of the dissolution inhibitory effect. Preferably, 0.15 mol to 1.5 mol is blended.

In the case of using a urea compound, the dissolution inhibitor according to the present invention is preferably from 0.1 mol to 2.0 mol with respect to 1 mol of the carboxyl group and the phenolic hydroxyl group of the polyimide precursor from the viewpoint of expression of the dissolution inhibitory effect. From the viewpoint of the dissolution inhibiting effect and the toughness of the resin obtained by baking, it is more preferable to add 0.15 mol to 1.5 mol.

Further, when both an amide compound and a urea compound are used, the total amount of the amide compound and the urea compound is from 0.1 mol to 1 mol of the carboxyl group and the phenolic hydroxyl group of the polyimide precursor from the viewpoint of the dissolution inhibiting effect. A range of 1.5 mol is preferred.

(E) Phenol compound A phenol compound can be mix | blended with the photosensitive polyimide precursor composition of this invention as needed. The phenol compound includes a compound represented by the following general formula (7) and a structure represented by the following general formula (8) from the viewpoint of reducing warpage of the sheet composed of the film and the substrate after baking and controlling the solubility in an alkaline aqueous solution. It is a phenol compound (assuming that it does not fall under the dissolution inhibitor of the present application).

(R ₇ and R ₈ each independently represents an organic group having 1 to 50 hydrogen atoms or carbon atoms and 0 to 10 oxygen atoms. X is independently a hydrogen atom, hydroxyl group or carbon number 1 to 20; Represents an organic group.)

(R ₉ and R ₁₁ each independently represents an organic group having 1 to 6 carbon atoms, and R ₁₀ represents a bonding group or an organic group having 1 to 20 carbon atoms.)

Specifically, dihydroxydiphenylmethane, 4,4′-oxydiphenol, 1,4-bis- (3-hydroxyphenoxy) -benzene, 1,3-bis- (4-hydroxyphenoxy) -benzene, 1,5 -Binuclear compounds such as bis- (o-hydroxyphenoxy) -3-oxapentane, α, α'-bis- (4-hydroxyphenyl) -1,4-diisopropylbenzene, tris (hydroxyphenyl) methane, tris ( Trinuclear compounds such as hydroxyphenyl) ethane, 4- {4- [1,1-bis (4-hydroxyphenyl) ethyl] -α, α-dimethylbenzyl} phenol, polynuclear compounds represented by the following structural formula group (a) Examples include the body. These phenol compounds may be used alone or in combination of two or more.

The compounding amount of the phenol compound according to the present invention is preferably 1 part by mass to 30 parts by mass, and more preferably 5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the polyimide precursor. When the blending amount is less than 1 part by mass, it becomes difficult to suppress the solubility in a developer composed of an alkaline aqueous solution, and when it exceeds 30 parts by mass, the photosensitive dry film obtained after the solvent removal step The photosensitive layer becomes brittle.

(F) Plasticizer In the photosensitive polyimide precursor composition according to the present invention, a compound represented by the following general formula (9) can also be suitably used as a plasticizer.

(R ₁₂ to R ₁₄ are organic groups containing an ethylene glycol chain and / or a propylene glycol chain, and may be the same or different.)

Specific examples include compounds represented by the following structural formulas (i) and (j), but are not limited thereto. These compounds may be used alone or in combination of two or more.

(D is an integer greater than 0, e is an integer greater than 0)

The compounding amount of the plasticizer according to the present invention is preferably 1 part by mass to 30 parts by mass, and more preferably 1 part by mass to 10 parts by mass with respect to 100 parts by mass of the polyimide precursor. When the blending amount is 1 part by mass or more, a warp reduction effect is exhibited, and when it is 30 parts by mass or less, a desired pattern is obtained without adversely affecting developability.

(G) Crosslinking agent In this invention, a crosslinking agent can be mix | blended in order to improve the toughness of the film after baking. As the crosslinking agent, a tetracarboxylic acid compound or a tetracarboxylic acid ester compound represented by the following general formula (10), a polyimide precursor or a carboxyl group-containing polyimide precursor ester compound represented by the following general formula (11) is preferable.

(R ₁₅ is a tetravalent organic group, R ₁₆ to R ₁₉ are hydrogen or a monovalent organic group having 1 to 20 carbon atoms, which may be the same or different.)

(R ₂₀ , R ₂₂ and R ₂₄ are tetravalent organic groups which may be the same or different. R ₂₁ and R ₂₃ are divalent organic groups which may be the same or different. R ₂₅ to R ₃₂ are hydrogen or a monovalent organic group having 1 to 20 carbon atoms, and may be the same or different, and g is an integer of 0 to 100.)

The amount of the crosslinking agent according to the present invention is preferably from 0.1 mol to 1.5 mol, preferably from 0.5 mol to 1.1 mol, from the viewpoint of expression of the crosslinking effect, relative to the number of moles of the remaining amino groups of the polyimide precursor. Is more preferable. The amount of residual amino groups can be calculated using high performance liquid chromatography.

(H) Thermal base generator The photosensitive polyimide precursor composition which concerns on this invention can contain a thermal base generator as needed. A thermal base generator is a compound that generates a base by heating. For example, it can be obtained by forming a salt structure with an amino group of a basic compound such as amine and an acid such as sulfonic acid, protecting with a dicarbonate compound, or protecting with an acid chloride compound. Thereby, it is stable without exhibiting basicity at room temperature, and can be a thermal base generator that generates a base by deprotection by heating. Moreover, it becomes possible to make the polyimide precursor baking temperature relatively low by blending the thermal base generator.

Specific examples of the thermal base generator include U-CAT (registered trademark) SA810, U-CAT SA831, U-CAT SA841, U-CAT SA851 (above, trade name: San Apro), N- (isopropoxycarbonyl) -2,6-dimethylpiperidine, N- (tert-butoxycarbonyl) -2,6-dimethylpiperidine, N- (benzyloxycarbonyl) -2,6-dimethylpiperidine, amino group of aromatic diamine with dibutyl dicarbonate Examples include protected compounds. Of these, N- (isopropoxycarbonyl) -2,6-dimethylpiperidine, N-, from the viewpoints of storage stability of the photosensitive polyimide precursor composition, molecular weight stability by solvent removal, alkali solubility, and ion migration properties. (Tert-butoxycarbonyl) -2,6-dimethylpiperidine, N- (benzyloxycarbonyl) -2,6-dimethylpiperidine, a compound in which the amino group of 4,4-diaminodiphenyl ether is protected with dibutyl dicarbonate, 3, 4 A compound in which the amino group of '-diaminodiphenyl ether is protected with dibutyl dicarbonate, a compound in which the amino group of 1,3-bis (3-aminophenoxy) benzene is protected with dibutyl dicarbonate, 1,3-bis (4-aminophenoxy) ) A compound in which the amino group of benzene is protected with dibutyl dicarbonate, trimethylene Bis compound protected dicarbonate dibutyl amino group of (4-aminobenzoate), 1,4-bis (4-aminophenoxy) compounds in which amino groups of pentane was protected by two-dibutyl carbonate are preferred. Such compounds are described in, for example, Chemistry Letters Vol. 34, no. 10 (2005).

The blending amount of the thermal base generator according to the present invention is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the polyimide precursor, from the viewpoint of acceleration of imidization and development performance, and 0.5 parts by mass. To 20 parts by mass is more preferable.

(I) Phosphate ester compound A phosphate ester compound can be mix | blended with the photosensitive polyimide precursor composition concerning this invention as needed. These compounds act as a flame retardant, a dissolution aid, and a plasticizer for the photosensitive polyimide precursor composition.

As the phosphoric ester compound, at least one compound selected from the group consisting of compounds represented by the following general formula (12), the following general formula (13) or the following general formula (14) is used.

(R ₃₅ from R ₃₃ represents a number 1 or more organic groups carbon, it may be the same or different, respectively.)

(R ₃₆ to R ₃₉ each represents an organic group having 1 or more carbon atoms, and may be the same or different.)

(In the formula, R ₄₀ is hydrogen or a monovalent organic group.)

In consideration of improving the flame retardancy and plasticity of the photosensitive polyimide precursor composition, R ₃₃ to R ₃₅ in the general formula (12) or R ₃₆ to R ₃₉ in the general formula (13) are methyl. An organic group selected from a group, an ethyl group, a butyl group, a 2-ethylhexyl group, a butoxyethyl group, a phenyl group, a cresyl group, a xylenyl group, and an aminophenyl group is preferable.

Similarly, when considering the thermal stability and the effect of improving the warp of the photosensitive dry film, R ₄₀ in the general formula (14) is hydrogen, dihydroxyphenyl group, dibutylhydroxybenzyl group, (meth) acrylate-containing organic group. It is preferable that it is an organic group chosen from these. Further, in consideration of the compatibility with the resin varnish and the effect of improving the warp when the photosensitive dry film is formed, R ₄₀ is preferably hydrogen.

These phosphate ester compounds can be used alone or in combination of two or more. The blending amount of these phosphate ester compounds is preferably 1 part by mass to 30 parts by mass, and more preferably 1 part by mass to 20 parts by mass. When the blending amount is 1 part by mass or more, plasticity is expressed. When the blending amount is 30 parts by mass or less, the portion of the photosensitive polyimide precursor composition that is not irradiated with actinic rays is less likely to be eroded by the developer composed of an alkaline aqueous solution. A good line image can be obtained.

(J) Organophosphorus Compound An organophosphorus compound represented by the following general formula (15) can be blended with the photosensitive polyimide precursor composition according to the present invention. By mix | blending the said organophosphorus compound, a flame retardance can be provided to the resin pattern obtained by baking.

(R ₄₁ represents an organic group. H represents an integer of 1 to 50.)

The compounding amount of these organic phosphorus compounds is preferably 1 part by mass to 30 parts by mass, and more preferably 3 parts by mass to 25 parts by mass. If the blending amount is 1 part by mass or more, flame retardancy is exhibited, and if it is 30 parts by mass or less, the resin pattern obtained after baking becomes tough.

(K) Other components An imidazole compound, a triazole compound, a tetrazole compound, and a sulfide compound can be mix | blended with the photosensitive polyimide precursor composition concerning this invention as needed. By blending these compounds, the adhesion to the copper substrate can be improved.

The compounding amount of these compounds is preferably 0.1 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass. When the blending amount is 0.1 parts by mass or more, an effect of improving adhesiveness is exhibited, and when it is 10 parts by mass or less, a good line image can be obtained without adversely affecting developability.

In the photosensitive polyimide precursor composition according to the present invention, for the purpose of improving the wettability with the support film, alcohols such as ethanol, 2-propanol and ethylene glycol, ethyl lactate, methyl benzoate, Esters such as ethylene glycol monopropyl ether acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethers such as n-butyl ether, tetrahydrofuran and dioxane, glycol ethers such as ethylene glycol monoethyl ether and propylene glycol monoethyl ether Can be blended.

The photosensitive polyimide precursor composition of the present invention can be used as a coverlay. A coverlay refers to a protective film that protects wiring formed on a silicon wafer, a copper clad laminate, an FPC, or the like.

(Preparation of photosensitive polyimide precursor composition)
The photosensitive polyimide precursor composition according to the present invention is prepared by mixing the polyimide precursor and various compounds in a suitable container, and is completely dissolved in a three-rotor motor equipped with a mix rotor, non-bubbling kneader, and stirring blades. It is obtained by stirring until

(Manufacture of resin patterns)
In this invention, a photosensitive dry film can be produced using the photosensitive polyimide precursor composition, and a resin pattern can be formed. The resin pattern can be formed by the following steps.

(1) A process of applying a photosensitive polyimide precursor composition to a film substrate and then removing the solvent to produce a photosensitive dry film

The photosensitive dry film is obtained by applying a photosensitive polyimide precursor composition to a support film (film substrate) and drying the solvent to form a photosensitive layer. As the support film, low density polyethylene, high density polyethylene, polypropylene, polyester, polycarbonate, polyarylate, polyacrylonitrile, ethylene / cyclodecene copolymer, and the like can be used. These support films can be subjected to surface treatment for the purpose of controlling the wettability of the photosensitive polyimide precursor composition and the peelability of the photosensitive layer obtained from the photosensitive polyimide precursor composition. . Examples of the surface treatment method include corona treatment, flame treatment, plasma treatment, surface modification using silicone, alkyd resin, olefin resin, and the like. The thickness of the carrier film is usually 15 μm to 100 μm, preferably 15 μm to 75 μm, in consideration of coating properties, adhesion, rollability, toughness, cost, and the like.

The photosensitive polyimide precursor composition can be applied to the above support film using a known method such as a reverse roll coater, a gravure roll coater, a comma coater, a lip coater, or a slot die coater.

Solvent removal can be performed by drying the solvent (drying using hot air, far infrared rays, or near infrared rays). The drying temperature is preferably from 50 ° C. to 120 ° C. from the viewpoint of suppressing the decrease in molecular weight, and more preferably from 50 ° C. to 110 ° C. from the viewpoint of the stability of the photosensitive agent. The film thickness of the photosensitive layer obtained by solvent removal is preferably 5 μm to 100 μm, more preferably 5 μm to 50 μm. The film thickness is preferably 5 μm or more from the viewpoint of insulation reliability, and preferably 100 μm or less from the viewpoint of obtaining a good line image. Here, if the ratio (Mw2 / Mw1) between the weight average molecular weight (Mw1) in the polyimide precursor varnish and the weight average molecular weight (Mw2) after solvent removal at 120 ° C. or lower is 0.7 or more, Even if the photosensitive dry film after solvent removal is folded, the photosensitive layer is not cracked.

Moreover, a cover film can be laminated on a photosensitive dry film to form a photosensitive laminated film. By laminating the cover film, adhesion of the photosensitive layer to the support film can be prevented. As the cover film, low density polyethylene, high density polyethylene, polypropylene, polyester, polycarbonate, polyarylate, polyacrylonitrile, ethylene / cyclodecene copolymer can be used.

(2) A process of forming a photosensitive layer by pressure-bonding a photosensitive dry film on a substrate on which a pattern is arranged. A photosensitive dry film is superimposed on a surface on which a circuit such as an FPC is formed (on a substrate on which a pattern is arranged) The photosensitive layer is laminated (press-bonded) at a pressure of 0.2 MPa to 5 MPa while being heated at 40 ° C. to 130 ° C., preferably 60 ° C. to 120 ° C., by a known method such as laminating, roll laminating or vacuum pressing. Can be stacked.

At this time, if the photosensitive dry film is a photosensitive laminated film in which a cover film is laminated, the cover film is peeled off before lamination. By setting the laminating temperature to 40 ° C. or higher, it is possible to eliminate troublesome work by tacking at the time of alignment before lamination, and by setting it to 130 ° C. or lower, it is possible to laminate without decomposing the photosensitive agent. Note that the temperature at which lamination is possible is that there is no problem such as remaining bubbles, and the pattern can be sufficiently embedded in the pattern, and at the same time, the photosensitive layer has a viscosity at which the photosensitive polyimide precursor composition does not flow out of the pattern. It means the temperature that can be controlled.

Further, by making the glass transition point (hereinafter referred to as Tg) of the photosensitive layer lower than the laminating temperature, the photosensitive dry film can be suitably laminated. After lamination of the photosensitive layer, the support film may or may not be peeled off. If the support film is not peeled after lamination, it is peeled off after the exposure step.

(3) Step of irradiating the photosensitive layer with actinic rays The photosensitive layer is exposed through a photomask on which an arbitrary pattern is drawn in order to form fine holes and fine width lines. Exposure varies depending on the composition of the photosensitive polyimide precursor composition is usually ^{100mJ / cm 2 ~ 3,000mJ / cm} 2. Examples of actinic rays used at this time include X-rays, electron beams, ultraviolet rays, and visible rays. As the active light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a halogen lamp, or the like can be used. In the present invention, it is preferable to use i-line (365 nm), h-line (405 nm), and g-line (436 nm) of a mercury lamp. As a method of irradiating with actinic rays, either contact exposure or projection exposure may be used.

(4) Step of developing with aqueous alkali solution After exposure, a developing solution is used, and development is performed by a known method such as an immersion method or a spray method to obtain a line image. As the developer, an aqueous alkali solution such as an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous sodium carbonate solution, an aqueous potassium carbonate solution, or an aqueous tetramethylammonium hydroxide solution can be used. In this step, it is preferable to perform development while heating the developer. By managing the development temperature, the development time can be controlled and the shape of the obtained line image can be maintained. From these viewpoints, the temperature of the developer is preferably 20 ° C. to 60 ° C., more preferably 25 ° C. to 50 ° C.

(5) Step of rinsing with at least one solvent selected from the group consisting of water and acidic aqueous solution After development, washing is performed by a known method such as an immersion method or a spray method. As the rinsing liquid, water or a solution obtained by adding an organic solvent to water can be used. In this step, it is preferable to maintain the rinse liquid at an appropriate temperature. Thereby, it is possible to remove residues on the substrate and the resin after development. The temperature of the rinsing liquid is preferably 15 ° C. to 60 ° C., more preferably 20 ° C. to 50 ° C. from the viewpoint of residue removal. After washing with a rinsing liquid, washing may be performed with an inorganic acid aqueous solution or an organic acid aqueous solution. Specific examples of the inorganic acid aqueous solution include a hydrochloric acid aqueous solution, a sulfuric acid aqueous solution, a phosphoric acid aqueous solution, and a boric acid aqueous solution. Specific examples of the organic acid aqueous solution include a formic acid aqueous solution, an acetic acid aqueous solution, a citric acid aqueous solution, and a lactic acid aqueous solution. The washing time with the inorganic acid aqueous solution or organic acid aqueous solution is preferably 5 seconds to 120 seconds, more preferably 10 seconds to 60 seconds, from the viewpoint of washing efficiency. When rinsing with an acidic aqueous solution, the acidic aqueous solution is preferably washed away with water.

(6) A process of irradiating the entire photosensitive layer with actinic rays After the rinsing process, the entire surface of the obtained line image may be irradiated with actinic rays. By decomposing the photosensitizer in this step, the time required for the subsequent curing step can be shortened. Furthermore, the light transmittance of the resin pattern obtained after the curing process can be increased.

In addition, this process can reduce the residual stress between the photosensitive agent-derived substrate and the photosensitive layer, reduce the warpage of the FPC and multilayer printed wiring board obtained in the resin pattern manufacturing process, and increase the folding resistance. Become. Exposure to irradiation in this step varies by the thickness of the type of photosensitive agent used and the photosensitive layer is usually 100 mJ / cm ² at 3,000 mJ / cm ^2. For example, when a naphthoquinone diazide compound is used for the photosensitive agent and the photosensitive layer has a thickness of 25 μm, the amount is preferably 500 mJ / cm ² or more from the viewpoint of photodecomposition of the photosensitive agent. Examples of actinic rays used at this time include X-rays, electron beams, ultraviolet rays, and visible rays. As the active light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a halogen lamp, or the like can be used. Among these, it is preferable to use i-line (365 nm), h-line (405 nm), and g-line (436 nm) of a mercury lamp. Moreover, it is possible to irradiate actinic light, heating as needed. From the viewpoint of workability, the heating temperature is preferably 30 ° C to 130 ° C, more preferably 40 ° C to 100 ° C.

(7) Baking process at 100 to 400 ° C. A resin pattern is formed by baking the line image obtained by the above process. Baking is carried out continuously or stepwise at a temperature of 100 ° C. to 400 ° C. for 5 minutes to 5 hours. And the processed product is completed. In the case of FPC, it is preferable to cure in a temperature range of 100 ° C. to 200 ° C. from the viewpoint of preventing oxidation of the wiring. Examples of the processed product thus obtained include FPC and multilayer printed wiring boards.

Hereinafter, the present invention will be specifically described by way of examples, but is not limited to these examples.

(Synthesis of polyimide precursor)
Synthesis Example 1 Synthesis of Polyimide Precursor (i) 6.4 g of 1,3-bis (3-aminophenoxy) benzene and 62 g of γ-butyrolactone were placed in a three-necked separable flask and stirred until a uniform solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride was added, and the mixture was stirred for 1 hour while cooling with ice and then for 6 hours at room temperature. Next, the polyimide precursor (i) was obtained by carrying out pressure filtration of the product with a 5-micrometer filter. Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (i), the solid content of the polyimide precursor (i) solution, and the weight average molecular weight.

Synthesis Example 2 Synthesis of polyimide precursor (ii) In a three-necked separable flask, 4.8 g of 1,3-bis (3-aminophenoxy) benzene, 6.8 g of polytetramethylene oxide-di-p-aminobenzoate, γ-butyrolactone 82 g was added and stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride was added, and the mixture was stirred for 1 hour while cooling with ice and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (ii). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (ii), the solid content of the polyimide precursor (ii) solution, and the weight average molecular weight.

Synthesis Example 3 Synthesis of polyimide precursor (iii) In a three-necked separable flask, 9.7 g of 1,3-bis (3-aminophenoxy) benzene, 13.7 g of polytetramethylene oxide-di-p-aminobenzoate, γ-butyrolactone 168.8 g was added and stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (iii). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (iii), the solid content of the polyimide precursor (iii) solution, and the weight average molecular weight.

Synthesis Example 4 Synthesis of Polyimide Precursor (iv) In a three-necked separable flask, 8.8 g of 1,3-bis (3-aminophenoxy) benzene, 12.4 g of polytetramethylene oxide-di-p-aminobenzoate, γ-butyrolactone 99.7 g was added and stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (iv). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (iv), the solid content of the polyimide precursor (iv) solution, and the weight average molecular weight.

Synthesis Example 5 Synthesis of polyimide precursor (v) In a three-necked separable flask, 10.0 g of trimethylene-bis (4-aminobenzoate), 13.1 g of polytetramethylene oxide-di-p-aminobenzoate, 104.1 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (v). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (v), the solid content of the polyimide precursor (v) solution, and the weight average molecular weight.

Synthesis Example 6 Synthesis of Polyimide Precursor (vi) In a three-necked separable flask, 9.8 g of trimethylene-bis (4-aminobenzoate), 12.9 g of polytetramethylene oxide-di-p-aminobenzoate, 103.1 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (vi). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (vi), the solid content of the polyimide precursor (vi) solution, and the weight average molecular weight.

Synthesis Example 7 Synthesis of polyimide precursor (vii) In a three-necked separable flask, 9.5 g of trimethylene-bis (4-aminobenzoate), 12.4 g of polytetramethylene oxide-di-p-aminobenzoate, 101.0 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (vii). Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (vii), the solid content of the polyimide precursor (vii) solution, and the weight average molecular weight.

Synthesis Example 8 Synthesis of polyimide precursor (viii) Trimethylene-bis (4-aminobenzoate) 9.1 g, polytetramethylene oxide-di-p-aminobenzoate 15.4 g, γ-butyrolactone 107.3 g in a three-necked separable flask And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (viii). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (viii), the solid content of the polyimide precursor (viii) solution, and the weight average molecular weight.

Synthesis Example 9 Synthesis of polyimide precursor (ix) In a three-necked separable flask, 9.8 g of trimethylene-bis (3-aminobenzoate), 12.9 g of polytetramethylene oxide-di-p-aminobenzoate, 103.1 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, a polyimide precursor (ix) was obtained by pressure filtration of the product with a 5 μm filter. Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (ix), the solid content of the polyimide precursor (ix) solution, and the weight average molecular weight.

Synthesis Example 10 Synthesis of polyimide precursor (x) 9.8 g of trimethylene-bis (4-aminobenzoate), poly (tetramethylene / 3-methyltetramethylene ether) glycol bis (4-aminobenzoate) 12 in a three-necked separable flask 9.9 g and γ-butyrolactone 103.1 g were added and stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 11.5 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (x). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (x), the solid content of the polyimide precursor (x) solution, and the weight average molecular weight.

Synthesis Example 11 Synthesis of polyimide precursor (xi) In a three-necked separable flask, 10.1 g of trimethylene-bis (4-aminobenzoate), 13.3 g of polytetramethylene oxide-di-p-aminobenzoate, 105.7 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of butanediol-bis-trimellitic anhydride ester and 11.9 g of decanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, a polyimide precursor (xi) was obtained by pressure filtration of the product with a 5 μm filter. Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (xi), the solid content of the polyimide precursor (xi) solution, and the weight average molecular weight.

Synthesis Example 12 Synthesis of Polyimide Precursor (xii) 9.8 g of trimethylene-bis (4-aminobenzoate), 12.9 g of polytetramethylene oxide-di-p-aminobenzoate, 110.4 g of γ-butyrolactone in a three-necked separable flask And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 14.6 g of icosanediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour while cooling with ice and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (xii). Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (xii), the solid content of the polyimide precursor (xii) solution, and the weight average molecular weight.

Synthesis Example 13 Synthesis of polyimide precursor (xiii) In a three-necked separable flask, 9.8 g of trimethylene-bis (4-aminobenzoate), 12.9 g of polytetramethylene oxide-di-p-aminobenzoate, 123.9 g of γ-butyrolactone And stirred until a homogeneous solution was obtained. Next, 10 g of pentanediol-bis-trimellitic anhydride ester and 20.4 g of polypropylenediol-bis-trimellitic anhydride ester were added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (xiii). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (xiii), the solid content of the polyimide precursor (xiii) solution, and the weight average molecular weight.

Synthesis Example 14 Synthesis of polyimide precursor (xiv) 9.4 g of 1,3-bis (3-aminophenoxy) benzene and 73 g of γ-butyrolactone were placed in a three-necked separable flask and stirred until a uniform solution was obtained. Next, 10 g of 4,4′-oxydiphthalic dianhydride was added, and the mixture was stirred for 1 hour while cooling with ice and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (xiv). Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (xiv), the solid content of the polyimide precursor (xiv) solution, and the weight average molecular weight.

Synthesis Example 15 Synthesis of Polyimide Precursor (xv) In a three-necked separable flask, 7.1 g of 1,3-bis (3-aminophenoxy) benzene and 64.3 g of γ-butyrolactone were added and stirred until a uniform solution was obtained. Next, 10 g of ethylenediol-bis-trimellitic acid ester was added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, the product was subjected to pressure filtration with a 5 μm filter to obtain a polyimide precursor (xv). Table 1 shows the molar ratio of the acid dianhydride and diamine of the obtained polyimide precursor (xv), the solid content of the polyimide precursor (xv) solution, and the weight average molecular weight.

Synthesis Example 16 Synthesis of polyimide precursor (xvi) In a three-necked separable flask, 2.7 g of 1,3-bis (3-aminophenoxy) benzene, 26.3 g of polytetramethylene oxide-di-p-aminobenzoate, γ-butyrolactone 91.0 g was added and stirred until a homogeneous solution was obtained. Next, 10 g of 4,4′-oxydiphthalic dianhydride was added, and the mixture was stirred for 1 hour while cooling with ice and then for 6 hours at room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide precursor (xvi). Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (xvi), the solid content of the polyimide precursor (xvi) solution, and the weight average molecular weight.

Synthesis Example 17 Synthesis of polyimide precursor (xvii) In a three-necked separable flask, 2.0 g of 1,3-bis (3-aminophenoxy) benzene, 19.9 g of polytetramethylene oxide-di-p-aminobenzoate, γ-butyrolactone 74.4 g was added and stirred until a homogeneous solution was obtained. Next, 10 g of ethylenediol-bis-trimellitic acid ester was added, and the mixture was stirred for 1 hour with ice cooling and then for 6 hours at room temperature. Next, a polyimide precursor (xvii) was obtained by pressure filtration of the product with a 5 μm filter. Table 1 shows the molar ratio between the acid dianhydride and diamine of the obtained polyimide precursor (xvii), the solid content of the polyimide precursor (xvii) solution, and the weight average molecular weight.

(Preparation of photosensitive polyimide precursor composition)
First, a predetermined amount of polyimide precursor is subdivided into a container such as a glass bottle. Next, a predetermined amount of additives such as a photosensitizer and a dissolution inhibitor are blended, and the mixture is stirred with a mix rotor until uniform. By these operations, a photosensitive polyimide precursor composition can be obtained.

(Measurement of weight average molecular weight)
1: Weight average molecular weight measurement of polyimide precursor 0.01 g of the synthesized polyimide precursor was measured with a precision balance and dissolved in 10 g of dimethylformamide (Wako Pure Chemical Industries, Ltd.). This solution was filtered through a 10 μm filter, and the molecular weight was measured by gel permeation chromatography (manufactured by JASCO Corporation) equipped with TSK-GEL SUPER HM-H (trade name, manufactured by Tosoh Corporation).

2: Weight average molecular weight measurement of photosensitive polyimide precursor composition Coating: A polyester film (manufactured by Unitika) placed on a coating table (manufactured by MATSUKI SCIENCE CO., LTD.) That can be vacuum-adsorbed and heated, and vacuum-adsorbed to form the polyester film. Was pasted. On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

Solvent removal: Solvent removal was performed with a dryer (SPH-201, manufactured by Espec Corp.) at 95 ° C. for 30 minutes.

Molecular weight measurement: 0.01 g of the photosensitive polyimide precursor composition obtained after solvent removal was measured with a precision balance and dissolved in 10 g of dimethylformamide (Wako Pure Chemical Industries, Ltd.). This solution was filtered through a 10 μm filter, and the molecular weight was measured by gel permeation chromatography (manufactured by JASCO Corporation) equipped with TSK-GEL SUPER HM-H (trade name, manufactured by Tosoh Corporation).

Calculation of molecular weight ratio: When the weight average molecular weight M1 of the photosensitive polyimide precursor composition varnish and the weight average molecular weight M2 of the photosensitive polyimide precursor composition after solvent removal are set, the molecular weight ratio was calculated by the following formula 1. .
Molecular weight ratio = M2 / M1

(Bending test)
Coating: A polyester film (manufactured by Unitika Co., Ltd.) was placed on a coating table (manufactured by Matsuki Kagaku Co., Ltd.) capable of vacuum adsorption and heating, and the polyester film was adhered by vacuum adsorption. On the polyester film, a photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 100 μm.

Bending test: The film obtained after solvent removal was bent at 180 degrees (goose folding), and cracking and peeling of the photosensitive layer were visually observed. When there was no crack and peeling, it was marked as “Good”, and when there was crack and peeling, it was marked as “X”.

(Warp evaluation)
Coating: A polyester film (manufactured by Unitika Co., Ltd.) was placed on a coating table (manufactured by Matsuki Kagaku Co., Ltd.) capable of vacuum adsorption and heating, and the polyester film was adhered by vacuum adsorption. On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

Vacuum press: Using a polyimide film (Kapton EN-100, trade name, manufactured by Toray DuPont) as a base material, the photosensitive dry film obtained in the solvent removal process by a vacuum press (SA-501, manufactured by Tester Sangyo Co., Ltd.) Vacuum pressing was performed under the conditions of a pressing temperature of 100 ° C., a pressing pressure of 0.5 MPa, a degree of vacuum of 15 kPa, and a pressing time of 1 minute.

Bake: Curing was performed under the conditions shown in Table 5 using a dryer (SPH-201, manufactured by Espec).

Measurement of warpage: The film obtained after baking was cut into a length of 5 cm and a width of 5 cm, static electricity was removed, and the warpage of the film was measured using a ruler.

Example 1
Evaluation of Photosensitive Polyimide Precursor Composition Comprising Polyimide Precursor and Photosensitizer 10 g of the polyimide precursor solution obtained in Synthesis Examples 1 to 3, and 20 parts by mass of a quinonediazide compound (formula) based on the polyimide precursor solid content as a photosensitizer 16) 0.42 g was mixed in the ratio shown in Table 2, put into a 20 cc glass bottle, stirred with a mix rotor (MR-5, manufactured by ASONE) until uniform, and a photosensitive polyimide precursor composition (1 to 3) was prepared. Obtained. The evaluation results are shown in Table 2.

(Example 2)
Evaluation of Photosensitive Polyimide Precursor Composition Using 3′-Hydroxyacetanilide as Dissolution Inhibitor 10 g of the polyimide precursor solution obtained in Synthesis Examples 1 to 3 and 20 parts by mass with respect to the polyimide precursor solid content as a photosensitive agent 0.42 g of the quinonediazide compound (formula 16) and 12.5 parts by mass of 3′-hydroxyacetanilide 0.26 g with respect to the polyimide precursor were mixed in the ratio shown in Table 3, and placed in a 20 cc glass bottle. No. 5 manufactured by ASONE Co., Ltd.) until stirring to obtain a photosensitive polyimide precursor composition (4 to 6). The evaluation results are shown in Table 3.

(Example 3)
Evaluation of Photosensitive Polyimide Precursor Composition Using Phenol Compound 10 g of the polyimide precursor solution obtained in Synthesis Examples 1 to 3, and 20 parts by mass of the general formula (16) based on the polyimide precursor solid content as a photosensitizer 0.42 g of the quinonediazide compound represented, and 0.42 g of the phenol compound represented by the following general formula (17) with respect to the polyimide precursor are mixed at a ratio shown in Table 4, and the mixture is put into a 20 cc glass bottle and mixed. The mixture was stirred until it became uniform with a rotor (MR-5, manufactured by ASONE) to obtain a photosensitive polyimide precursor composition (7 to 9). The evaluation results are shown in Table 4.

(Comparative Example 1)
A photosensitive polyimide precursor composition (10 to 11) shown in Table 2 was obtained in the same manner as in Example 1 except that 10 g of the polyimide precursor solution obtained in Synthesis Examples 14 to 15 was used. The evaluation results are shown in Table 2.

(Comparative Example 2)
A photosensitive polyimide precursor composition (12 to 13) shown in Table 3 was obtained in the same manner as in Example 2 except that 10 g of the polyimide precursor solution obtained in Synthesis Examples 14 to 15 was used. The evaluation results are shown in Table 3.

(Comparative Example 3)
A photosensitive polyimide precursor composition (14 to 15) shown in Table 4 was obtained in the same manner as in Example 3 except that 10 g of the polyimide precursor solution obtained in Synthesis Examples 14 to 15 was used. The evaluation results are shown in Table 4.

When the photosensitive polyimide precursor composition is used for a cover film of a flexible printed wiring board, it is necessary to obtain a desired pattern by lithography with a developer composed of an alkaline aqueous solution. In addition to the fact that the molecular weight of the composition does not change over time, it is excellent in tackiness, the laminate in which the cover film is laminated after baking is not warped, and peels off even when bent and cracks occur. There are demands for performance such as lack of heat and the ability of the laminate to burn.

(Performance evaluation of photosensitive polyimide precursor composition)
1) Evaluation of material stability Coating: A polyester film (manufactured by Unitika Co., Ltd.) was placed on a coating table (manufactured by Matsuki Kagaku Co., Ltd.) that can be vacuum-adsorbed and heated, and the polyester film was adhered by vacuum adsorption. On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

2: Lithographic performance evaluation Coating: A polyester film (manufactured by Unitika) was placed on a coating table (manufactured by Matsuki Kagaku Co., Ltd.) that can be vacuum-adsorbed and heated, and the polyester film was adhered by vacuum-adsorbing. On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

Vacuum press: First, FCCL was washed with a 15 wt% sodium persulfate aqueous solution. Next, the photosensitive dry film obtained in the solvent removal step was subjected to a press temperature of 100 ° C., a press pressure of 0.5 MPa, a vacuum degree of 15 kPa, and a press time of 1 minute using a vacuum press machine (SA-501, manufactured by Tester Sangyo Co., Ltd.). A vacuum press was performed.

Actinic ray irradiation: The support film of the laminate obtained in the vacuum pressing process was peeled off, and irradiated with ultraviolet rays under an exposure amount of 1.5 J / cm ² using an ultrahigh pressure mercury lamp (manufactured by HMW-201KB Oak).

Lithography: Using a spray-type developing machine, a time until a UV irradiation part is completely dissolved under the conditions of a developing temperature of 30 ° C. and a spray pressure of 0.18 MPa using a 1 wt% sodium carbonate aqueous solution as a developing solution (hereinafter referred to as a breakpoint) To be described). Next, development was performed with a development time 1.2 times the breakpoint. After development, washing was performed for 1/3 of the development time with distilled water in a spray type washer, and further for 30 seconds with a 0.2 wt% aqueous sulfuric acid solution.

Lithographic performance: Lithographic performance was judged by development time, remaining film rate and pattern shape.

Development time: A photosensitive polyimide precursor composition having a development time of 90 seconds or less was indicated by ◯, and a photosensitive polyimide precursor composition having a development time exceeding 90 seconds was indicated by ×.

Residual film ratio measurement: The film thickness of the photosensitive layer before development was T1, and the film thickness of the photosensitive layer after development was T2.
Remaining film ratio = T2 / T1 x 100 (%)

Pattern shape: The pattern after lithography was observed using a light microscope (ECLIPS LV100, manufactured by Nikon Corp.) with a bright field at 100 times the shape of a 100 μm circle pattern. An object holding the shape of the pattern was indicated as “◯”, and an object that collapsed was indicated as “X”.

3: Evaluation of tackiness of photosensitive dry film Coating: A polyester film (manufactured by Unitika) was placed on a coating table (manufactured by Matsuki Kagaku) that can be vacuum-adsorbed and heated, and the polyester film was adhered by vacuum-adsorbing. . On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

Evaluation of tackiness: The presence or absence of tackiness of the photosensitive layer after solvent removal was evaluated by palpation. Those with fingerprints were marked with ×, and those without fingerprints were marked with ○.

4: Evaluation of folding resistance Cure: After lithography, curing was performed under the conditions shown in Table 5 using a dryer (SPH-201 manufactured by Espec).

Bending test: The film obtained after curing was bent at 180 degrees (haze fold), and the cover film was visually observed for cracking and peeling. When there was no crack and peeling, it was marked as “Good”, and when there was crack and peeling, it was marked as “X”.

5: Warpage evaluation Coating: A polyester film (manufactured by Unitika Ltd.) was placed on a coating table (manufactured by Matsuki Kagaku Co., Ltd.) that can be vacuum-adsorbed and heated, and the polyester film was adhered by vacuum-adsorbing. On the polyester film, the photosensitive polyimide precursor composition was applied using an applicator (manufactured by Matsuki Scientific Co., Ltd.) having a gap of 67.5 μm.

6: Flame retardancy evaluation The coating and solvent removal were performed in the same manner as the warpage evaluation.
Vacuum press: Using a polyimide film (Kapton EN-100, trade name, manufactured by Toray DuPont) as a base material, the photosensitive dry film obtained in the solvent removal process was obtained using a vacuum press (SA-501 Tester Sangyo Co., Ltd.). Vacuum pressing was performed on both sides of the polyimide film under the conditions of a pressing temperature of 100 ° C., a pressing pressure of 0.5 MPa, a degree of vacuum of 15 kPa, and a pressing time of 1 minute.

Flame retardance test: The film obtained in the baking process was cut into a width of 1 cm and a length of 5 cm. Next, the process of igniting one end of the test piece and spreading it was visually observed. A sample that was extinguished during the course was marked with ◯, and a sample that had all burned was marked with ×.

(Examples 4 to 22)
To 10 g of the polyimide precursor solution obtained in Synthesis Example 2 to Synthesis Example 13, various additives were mixed in the proportions shown in Table 6-1 and placed in a 20 cc glass bottle, and a mix rotor (manufactured by MR-5 ASONE) To obtain a photosensitive polyimide precursor composition (16 to 34). Table 7-1 shows the evaluation results of these photosensitive polyimide precursor compositions.

(Comparative Examples 4 to 7)
Various additives were mixed in the proportions shown in Table 6-2 with 10 g of the polyimide precursor solution obtained in Synthesis Example 16 to Synthesis Example 17, and placed in a 20 cc glass bottle. Mix rotor (manufactured by MR-5 ASONE) To obtain a photosensitive polyimide precursor composition (35 to 38). The evaluation results of these photosensitive polyimide precursor compositions are shown in Table 7-2.

In Examples 4 to 22 and Comparative Examples 4 to 7, compounds of the following formulas (18) to (27) were used as additives.

Dissolution inhibitor 1

Dissolution inhibitor 2

Flame retardants

Thermal base generator

As shown in Tables 2 to 4, Examples 1 to 3 using the polyimide precursor according to the present invention show no decrease in molecular weight (M2 / M1). Moreover, the goby folding strength was also good. This result is considered to be because by using the acid dianhydride according to the present invention, decomposition of the polyimide precursor at the time of solvent removal was suppressed and molecular weight reduction was suppressed. On the other hand, in Comparative Examples 1 to 3 using other acid dianhydrides, it can be seen that the molecular weight decreases and the goby folding strength decreases.

Further, as shown in Table 7-1 and Table 7-2, Examples 4 to 22 using the polyimide precursor composition according to the present invention show that the remaining film ratio is good. . In particular, in Example 8, the remaining film ratio is 90% without adding a dissolution inhibitor. These results are considered to be because decomposition of the polyimide precursor in the development process was suppressed by using the acid dianhydride according to the present invention. Examples 4 to 22 show that the tackiness is also good. On the other hand, under any conditions using other acid dianhydrides, the remaining film ratio is reduced, indicating that the tackiness is poor.

The polyimide precursor of the present invention includes a surface protective film for a semiconductor device, an interlayer insulating film, a rewiring insulating film, a protective film for a device having a bump structure, an interlayer insulating film for a multilayer circuit, a cover coat for a flexible copper-clad plate, Moreover, it can utilize suitably as a liquid crystal aligning film etc.

Claims

A polyimide precursor comprising an acid dianhydride represented by the following general formula (1).

(X is a divalent organic group having an alkylene group having 3 to 30 carbon atoms. R 1 represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. .)
The said polyimide precursor contains the diamine represented by following General formula (2), The polyimide precursor of Claim 1 characterized by the above-mentioned.

(Y is a divalent organic group having an alkylene group having 2 to 20 carbon atoms. R 2 represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. .)
The said polyimide precursor contains the acid dianhydride represented by following General formula (3), The polyimide precursor of Claim 1 or Claim 2 characterized by the above-mentioned.

(A represents an integer of 1 to 20. b represents an integer of 3 to 30. R 3 represents a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)
The said polyimide precursor contains the diamine represented by following General formula (4), The polyimide precursor of Claim 1 or Claim 2 characterized by the above-mentioned.

(Z represents an alkylene group having 2 to 20 carbon atoms. R 4 represents a hydrogen atom, a monovalent alkyl group having 1 to 10 carbon atoms, an alkoxy group, or a halogen group. C represents 2 to 30 carbon atoms. Represents an integer.)
The said polyimide precursor contains the acid dianhydride represented by following General formula (3), The polyimide precursor of Claim 2 characterized by the above-mentioned.

(A represents an integer of 1 to 15. b represents an integer of 5 to 20. R 3 represents a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)
The polyimide precursor according to claim 4, wherein the diamine represented by the general formula (4) is 25 mol% to 75 mol% of all diamine components.
A photosensitive polyimide precursor comprising 100 parts by weight of the polyimide precursor according to claim 1, 2 or 5, and 5 to 35 parts by weight of a photosensitive agent. Composition.
The photosensitive polyimide precursor composition according to claim 7, wherein the photosensitive agent contains a quinonediazide structure.
The photosensitive polyimide precursor composition according to claim 7, comprising a dissolution inhibitor having a phenolic hydroxyl group.
A photosensitive dry film obtained by coating the photosensitive polyimide precursor composition according to any one of claims 7 to 9 on a support film, removing the solvent, and then laminating a cover film.
A flexible printed wiring board formed using the photosensitive dry film according to claim 10.
A polyimide precursor characterized in that the ratio (Mw2 / Mw1) between the weight average molecular weight (Mw1) in the varnish and the weight average molecular weight (Mw2) after desolvation at 120 ° C. or lower is 0.7 or more .