KR102130430B1 - Photosensitive film laminate, flexible printed wiring board, and method for manufacturing same - Google Patents

Abstract

(식(1) 중, Ar₁은, 방향족을 포함하여 이루어진 1가의 유기기, R₁은, 알킬기 또는 아릴기를 갖는 유기기, R₂는, 분기쇄 알킬기, 직쇄 알킬기, 지환 구조를 갖는 알킬기, 또는 방향족 구조를 갖는 알킬기 중 어느 것인 탄소수 3∼탄소수 50의 1가의 탄화수소기이다.)
알칼리 현상 가능하고 광감도가 우수하고, 박막화한 경우라 하더라도 우수한 배선 피복성을 가지며, 노광부와 미노광부의 시인성이 우수한 감광성 필름 및 그것을 이용한 플렉시블 프린트 배선판을 제공할 수 있다. The photosensitive film laminate is formed on a substrate, a substrate, and contains (A) an alkali-soluble resin, (B) a polymerizable compound having an unsaturated double bond, and (C) a photopolymerization initiator, and (C) a photopolymerization initiator. A is provided with a photosensitive film comprising a photosensitive resin composition having a structure represented by the following formula (1).

(In formula (1), Ar ₁ is a monovalent organic group comprising aromatics, R ₁ is an organic group having an alkyl group or an aryl group, R ₂ is a branched chain alkyl group, a straight chain alkyl group, an alkyl group having an alicyclic structure, Or it is a monovalent hydrocarbon group having 3 to 50 carbon atoms, which is any of the alkyl groups having an aromatic structure.)
It is possible to provide a photosensitive film capable of alkali development, excellent light sensitivity, excellent wiring coverage even in the case of thin film, excellent visibility of exposed and unexposed portions, and a flexible printed wiring board using the same.

Description

Photosensitive film laminate, flexible printed wiring board and its manufacturing method{PHOTOSENSITIVE FILM LAMINATE, FLEXIBLE PRINTED WIRING BOARD, AND METHOD FOR MANUFACTURING SAME}

The present invention relates to a photosensitive film laminate using a photosensitive film containing a photosensitive resin composition, a flexible printed wiring board, and a method for manufacturing the same, useful as a protective film for a surface protective film, an interlayer insulating film, a semiconductor package substrate, or a flexible printed circuit board of a semiconductor device will be.

Recently, a film-type printed board called a flexible printed board (hereinafter also referred to as "FPC") has been booming. This FPC has a structure with a coverlay composed of polyimide film, etc., on a wired FCCL (Flexible Copper Clad Laminate), and is mainly used in mobile phones, smartphones, tablet-type terminals, notebook computers, and digital cameras. It is used for devices such as. Since the FPC retains its function even when bent, it has become an indispensable material for downsizing and weight reduction of equipment. In particular, in recent years, miniaturization and weight reduction of electronic devices represented by smartphones or tablet-type terminals are in progress, and by adopting FPC in these products, the size and weight of the electronic devices are reduced, and product costs are reduced and design is simplified. It contributes to things.

The FPC is formed with a coverlay, which is a layer of insulating material used to fully or partially cover the conductor pattern on the outer surface of the printed plate. The most basic coverlay is a film coverlay composed of a highly reliable non-photosensitive punching material, but it is very difficult to automate the bonding process, and even an attempt to roll-to-roll is not made, so that it is relied on in the human hand. As a practical solution of the coverlay treatment process, screen printing of coverlay ink is considered, such as a solder mask of a hard printed board, but all commercially available materials have mechanical properties, compared to film coverlay. The chemical resistance (especially plating resistance) is poor, and is not widely used in general.

In order to refine the FPC and make the manufacturing process viable, development of a photosensitive coverlay for performing fine processing by lithography has been energetically performed. Due to environmental considerations in recent years, material design has been made in response to the development of an aqueous alkali solution, and among them, the photosensitive coverlay using a polyimide precursor has mechanical properties such as electrical insulation reliability and bending resistance derived from polyimide, heat resistance, and heat resistance. It is expected as an excellent coverlay from the viewpoints of chemical properties and flame retardancy. In particular, the dry film-type photosensitive coverlay film not only reduces the labor and time of application and drying as compared with the method of applying a liquid photosensitive resin, but also makes a number of perforations by laminating and lithography in both sides of the batch. Since the roll-to-roll production method in which processing is performed at one time becomes possible, it is possible to achieve shortening and viability of the FPC manufacturing process.

In order to obtain a photosensitive polyimide capable of developing such an alkali aqueous solution, an alkali negative developing photosensitive polyimide precursor by a method of introducing a photoreactive group to a part of the total alkali-soluble group or an alkali-soluble polyimide in which an alkali-soluble group is introduced into the polyimide On the other hand, a negative photosensitive polyimide by a method of adding a polymerizable compound and a photopolymerization initiator has been developed (for example, see Patent Documents 1 to 3).

However, sufficient photosensitivity could not be obtained with such photosensitive polyimide. On the other hand, photosensitive resin compositions using specific oxime compounds as photopolymerization initiators with high photosensitivity have also been developed (for example, see Patent Documents 4 and 5).

[ Prior art literature ]

[ Patent document ]

(Patent Document 1) Patent Document 1: Japanese Patent Publication No. Hei 3-220558

(Patent Document 2) Patent Document 2: Japanese Patent Publication No. 2002-182378

(Patent Document 3) Patent Document 3: Pamphlet of International Publication No. 2004/109403

(Patent Document 4) Patent Document 4: Japanese Patent Publication No. 2004-534797

(Patent Document 5) Patent Document 5: Japanese Patent Publication No. 2007-133377

However, when the photosensitive coverlay is also thinned in response to the demand for thinning of the process circuit board, when the photosensitive resin composition as described in Patent Document 5 is used, coating reliability on the wiring may deteriorate. In addition, the visibility of the exposed portion and the unexposed portion required to avoid double exposure in the production site may not be sufficiently obtained.

The present invention has been made in consideration of such a point, and is capable of alkali development, has excellent light sensitivity, and furthermore, has excellent wiring coverage even in the case of thin film, and has excellent visibility of the exposed portion and the unexposed portion. It aims to provide a film laminated body, a flexible printed wiring board, and its manufacturing method.

The photosensitive film layered product of the present invention comprises a substrate, (A) an alkali-soluble resin, (B) a polymerizable compound having an unsaturated double bond, and (C) a photopolymerization initiator, and (C) The photopolymerization initiator is characterized by comprising a photosensitive film comprising a photosensitive resin composition having a structure represented by the following formula (1).

(In formula (1), Ar ₁ is a monovalent organic group comprising aromatics, R ₁ is an organic group having an alkyl group or an aryl group, R ₂ is a branched chain alkyl group, a straight chain alkyl group, an alkyl group having an alicyclic structure, Or it is a monovalent hydrocarbon group having 3 to 50 carbon atoms, which is any of the alkyl groups having an aromatic structure.)

The flexible printed wiring board of the present invention is characterized by comprising a circuit board having wiring, and the photosensitive film fired on the circuit board.

The method for manufacturing a flexible printed wiring board of the present invention is characterized in that the above photosensitive film laminate is laminated on a wiring surface on a circuit board having wiring, by using a roll type thermal vacuum laminator, and then plastically formed.

The flexible printed wiring board of the present invention is characterized by being manufactured by the above manufacturing method.

The flexible printed wiring board of the present invention is a flexible printed wiring board comprising a circuit board having wiring and a film obtained by firing a coverlay film formed to cover the wiring on the circuit board, which is obtained by firing on the wiring. It is characterized in that the minimum thickness (a) of the film is 0.1 µm or more and less than 10 µm.

The flexible printed wiring board of the present invention is a flexible printed wiring board comprising a circuit board having wiring, and a film obtained by firing a coverlay film formed to cover the wiring on the circuit board, wherein the wiring has no wiring and a portion without wiring. It is characterized in that the maximum value (b) of the surface step difference of the film obtained by firing is 3 µm or less.

According to the present invention, a photosensitive film laminate using a photosensitive film that is capable of alkali development, has excellent light sensitivity, and also has excellent wiring coverage even when thinned, and has excellent visibility of exposed and unexposed portions, flexible printed wiring board And its manufacturing method.

1 is an explanatory view showing a minimum thickness and a surface level difference of the flexible printed wiring board according to the present embodiment.

Hereinafter, a form (hereinafter abbreviated as an embodiment) for carrying out the present invention will be described in detail. Moreover, this invention is not limited to the following embodiment, It can be implemented by carrying out modification within the range of the summary.

The photosensitive film laminate according to the present embodiment has a photosensitive film comprising a substrate and a photosensitive resin composition formed on the substrate. The photosensitive resin composition according to the present embodiment contains (A) an alkali-soluble resin, (B) a polymerizable compound having an unsaturated double bond, and (C) a photopolymerization initiator, and (C) the photopolymerization initiator is represented by the following formula ( It is a structure represented by 1).

(In formula (1), Ar ₁ is a monovalent organic group comprising aromatics, R ₁ is an organic group having an alkyl group or an aryl group, R ₂ is a branched chain alkyl group, a straight chain alkyl group, an alkyl group having an alicyclic structure, Or it is a monovalent hydrocarbon group having 3 to 50 carbon atoms, which is any of the alkyl groups having an aromatic structure.)

According to this photosensitive film, since (A) contains an alkali-soluble resin, alkali development becomes possible, and (C) since the photopolymerization initiator having a structure represented by the formula (1) is included, the light sensitivity is improved. And since this (C) photopolymerization initiator introduces a hydrophobic or bulky skeleton to R ₂ , the compatibility of (C) photopolymerization initiator and (B) polymerizable compound is improved. Accordingly, the polymerization reactivity of the photopolymerization initiator (C) and the polymerizable compound (B) is improved, so that a three-dimensional network by crosslinking between the molecular chains is suitably formed. As a result, a photosensitive film excellent in photosensitivity that is easily dissolved in an alkali developer before exposure and insoluble in an alkali developer after exposure can be obtained. The photosensitive film has excellent wiring coverage even when thinned, and has excellent visibility of the exposed portion and the unexposed portion. Hereinafter, each configuration requirement will be described.

<Photosensitive resin composition>

(A) alkali-soluble resin

First, the alkali-soluble resin in the photosensitive resin composition according to the present embodiment will be described. As the alkali-soluble resin, various polymers conventionally used in photosensitive resin compositions can be used. Examples of such polymers include (meth)acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, phenol novolak resins, cresol novolak resins, polyimide precursors, and And an organic polymer polymer soluble in an alkali developer such as a polyimide resin having a carboxyl group or a hydroxyl group on the side chain. In addition, (meth)acrylic acid copolymer means both acrylic acid copolymer and methacrylic acid copolymer.

As the alkali-soluble resin, the aforementioned polymers may be used alone, or two or more kinds thereof may be mixed and used. As the alkali-soluble resin, those having a weight average molecular weight of 10000 to 250000 and an acid value of 50 mgKOH/g to 300 mgKOH/g are preferably used.

As the alkali-soluble resin, a polyimide precursor is particularly preferable from the viewpoint of obtaining a coverlay having excellent mechanical properties such as electrical insulation reliability and bending resistance, heat resistance, chemical resistance, and flame retardancy. Moreover, it is preferable to use a polyimide precursor also in realizing high wiring coverage under conditions of a low exposure amount, an over-development condition, and a thinner film than a suitable photolithography condition. Moreover, a polyimide precursor means that it becomes a polyimide by imidization, and does not mean only polyamic acid, but also includes a part of a polyamic acid imidized.

The polyimide precursor can be obtained, for example, by reacting tetracarboxylic dianhydride with diamine. The tetracarboxylic dianhydride used is not limited, and a conventionally known tetracarboxylic dianhydride can be used. As tetracarboxylic dianhydride, aromatic tetracarboxylic acid, aliphatic tetracarboxylic dianhydride, or the like can be applied. Further, the diamine used is not limited, and conventionally known diamines can be used.

As the tetracarboxylic dianhydride, biphenyl-3,3',4,4'-tetracarboxylic dianhydride (hereinafter abbreviated as "BPDA"), benzophenone-3,3',4,4'-tetra Carboxylic acid dianhydride (hereinafter abbreviated as "BTDA"), oxydiphthalic acid dianhydride (hereinafter abbreviated as "ODPA"), diphenylsulfone-3,3',4,4'-tetracarboxylic dianhydride, ethylene Glycol bis (trimellitic acid monoesteric acid anhydride) (hereinafter abbreviated as "TMEG"), p-phenylenebis (trimellitic acid monoesteric acid anhydride), p-biphenylenebis (trimellitic acid monoesteric acid anhydride) ), m-phenylene bis (trimellitic acid monoesteric acid anhydride), o-phenylene bis (trimellitic acid monoesteric acid anhydride), pentanediol bis (trimellitic acid monoesteric acid anhydride) (hereinafter ``5-BTA ”, Decanediol bis (trimellitic acid monoesteric acid anhydride), pyromellitic anhydride, bis(3,4-dicarboxyphenyl) ether dianhydride, 4,4′-(2,2-hexafluoro Isopropylidene)diphthalic acid dianhydride, meta-terphenyl-3,3',4,4'-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2 ,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1-carboxymethyl-2,3 ,5-cyclopentatricarboxylic acid-2,6:3,5-dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene And -1,2-dicarboxylic acid anhydride and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride. The above-mentioned tetracarboxylic dianhydride may be used alone or in combination of two or more. Moreover, BPDA, ODPA, BTDA, TMEG, 5-BTA and decandiol bis (trimellitic acid monoester acid anhydride) are more preferable from the viewpoint of developability of the polyimide precursor.

Examples of diamines are 1,3-bis(4-aminophenoxy)alkane, 1,4-bis(4-aminophenoxy)alkane, 1,5-bis(4-aminophenoxy)alkane, 1,4- Diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodi Phenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)- 4,4'-diaminobiphenyl, 3,7-diamino-dimethyldibenzothiophene-5,5-dioxide, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4 ,4'-bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane, 1,2-bis[ 2-(4-aminophenoxy)ethoxy]ethane, 9,9-bis(4-aminophenyl)fluorene, 5-amino-1-(4-aminomethyl)-1,3,3-trimethylindan, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene (hereinafter abbreviated as "APB") , 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 2,2-bis(4-aminophenoxyphenyl)propane (hereinafter `` BAPP”, trimethylene-bis(4-aminobenzoate) (hereinafter abbreviated as “TMAB”), 4-aminophenyl-4-aminobenzoate, 2-methyl-4-aminophenyl-4- Aminobenzoate, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl ]Hexafluoropropane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,5-diamino And benzoic acid, 3,3'-dihydroxy-4,4'-diaminobiphenyl and 1,3-bis(4-aminophenoxybenzene). Among them, APB, BAPP and TMAB are preferred from the viewpoint of lowering the glass transition point (Tg) of the polyimide precursor and improving developability. These diamines can also be used as a diamine component used for synthesis of the polyimide structure of the polyimide precursor to be described later.

In the photosensitive resin composition according to the present embodiment, as a polyimide precursor, from a viewpoint of developability and molecular weight stability, a polyimide structure represented by the following formula (5) and a polyamic acid structure represented by the following formula (6) It is especially preferable to have each as a repeating structural unit.

(In formulas (5) and (6), R ₉ , R ₁₀ , R ₁₂ , R ₁₃ , R ₁₅ , R ₁₆ , R ₁₈ , R ₁₉ , R ₂₁ and R ₂₂ are each independently a hydrogen atom or carbon number Represents a monovalent organic group having 1 to 20 carbon atoms, and may be the same or different, R ₁₁ , R ₁₄ , R ₁₇ , R ₂₀ and R ₂₃ represent a tetravalent organic group having 1 to 20 carbon atoms, m, n and p each independently represents an integer of 0 to 100. R ₂₄ represents a tetravalent organic group, R ₂₅ represents a divalent organic group having 1 to 90 carbon atoms, and R ₂₆ has 1 to 50 carbon atoms. It represents a tetravalent organic group.)

Moreover, as a polyimide precursor, it is preferable that diamine represented by the following general formula (7) is included as a diamine component which comprises the polyimide structure represented by said general formula (5).

(In formula (7), R ₉ , R ₁₀ , R ₁₂ , R ₁₃ , R ₁₅ , R ₁₆ , R ₁₈ , R ₁₉ , R ₂₁ and R ₂₂ are each independently a hydrogen atom or a carbon number of 1 to 20 carbon atoms. It represents a monovalent organic group, and may be the same or different R ₁₁ , R ₁₄ , R ₁₇ , R ₂₀ and R ₂₃ represent a tetravalent organic group having 1 to 20 carbon atoms, and m, n and p are each independently It is an integer of 0 or more and 30 or less, and satisfies 1≤(m+n+p)≤30.)

In the polyimide precursors represented by the above formulas (5) and (6), since the oxyalkylene skeleton introduced into the molecular chains of the polyimide precursors, moderate flexibility is imparted to the molecular chains of the polyimide precursors. It becomes possible to improve the developability of the photosensitive resin composition. Here, when the oxyalkylene skeleton is introduced into the polyamic acid structure portion of the polyimide precursor by the diamine represented by the formula (7), a secondary amino group derived from the diamine is introduced into the polyamic acid structure portion. This secondary amino group has a problem that the basicity is high and the depolymerization of the polyamic acid structure is promoted and the molecular weight of the polyimide precursor is significantly reduced compared to conventional polyamic acid. For this reason, in this embodiment, by introducing the oxyalkylene skeleton with the diamine represented by the formula (7) into the polyimide structure portion of the polyimide precursor, the adverse effects of the basicity of the secondary amino group described above are prevented, , Developing the photosensitive resin composition can be improved while stabilizing the molecular weight.

M, n and p in the formula (5) are each independently an integer of 0 or more and 30 or less. From the viewpoint of insulation reliability, 1≤(m+n+p)≤30 is preferable, and 3≤(m+n+p)≤10 is more preferable. If it is in the range of 1≤(m+n+p)≤30, the skeleton having an oxyalkylene group is shortened, so it is estimated that the elastic modulus of the polyimide precursor is increased and the insulation reliability is improved.

The diamine represented by the formula (7) is not limited as long as the polyimide structure represented by the formula (5) can be obtained. Examples of such diamines include polyoxyethylenediamine compounds such as 1,8-diamino-3,6-dioxyoctane, polyoxyalkylenediamine compounds such as Jeffamine EDR-148 and EDR-176 manufactured by Huntsman, and Jeffamine Polyoxypropylenediamine compounds such as D-230, D-400, D-2000, D-4000, and polyetheramines D-230, D-400, D-2000 manufactured by BASF, and HK-511, ED-600, And compounds having different oxyalkylene groups such as ED-900, ED-2003, and XTJ-542. The skew of FPC after firing of the polyimide can be reduced by the skeleton having these oxyalkylene groups.

The main chain end of the polyimide precursor is not particularly limited as long as the structure does not affect performance. The acid dianhydride used in the production of the polyimide precursor, or a terminal structure derived from diamine may be used, or a structure in which the terminal is sealed with other acid anhydride or amine compound or the like.

It is preferable that it is 1000 or more and 1000000 or less as a weight average molecular weight of a polyimide precursor. Here, the weight average molecular weight refers to a molecular weight measured by gel permeation chromatography using polystyrene having a known weight average molecular weight as a standard. The weight average molecular weight is preferably 1000 or more from the viewpoint of the strength of the resin layer obtained by the photosensitive resin composition, and is preferably 1000000 or less from the viewpoint of viscosity and moldability of the photosensitive resin composition. The weight average molecular weight is more preferably 5000 or more and 500000 or less, particularly preferably 10000 or more and 300000 or less, and most preferably 15000 or more and 80000 or less.

The polyimide precursor having a polyimide structure and a polyamic acid structure as repeating units, respectively, is a step of reacting an acid dianhydride and diamine in a boiling molar amount to synthesize a polyimide portion in the first step (step 1), followed by a second step It can be produced by a step of synthesizing the polyamic acid portion (step 2). Hereinafter, each process is demonstrated.

(Process 1)

The process of synthesizing the polyimide portion of the first step will be described. The process for synthesizing the polyimide portion of the first step is not particularly limited, and a known method can be applied. More specifically, the polyimide portion can be synthesized by the following method. First, diamine is dissolved and/or dispersed in a polymerization solvent, and an acid dianhydride powder is added thereto. Then, an azeotrope with water was added, and the mixture was heated and stirred for 0.5 hour to 96 hours, more preferably 0.5 hour to 30 hours, while azeotropically removing the by-product water using a mechanical stirrer. At this time, the monomer concentration is preferably 0.5 mass% or more and 95 mass% or less, and more preferably 1 mass% or more and 90 mass% or less.

The polyimide portion can be synthesized by adding a known imidization catalyst or by using a non-catalyst. The imidization catalyst is not particularly limited, but acid anhydrides such as acetic anhydride, lactones such as γ-valerolactone, γ-butyrolactone, γ-tetraronic acid, γ-phthalide, γ-coumarin, and γ-phthalic acid Compounds and tertiary amines such as pyridine, quinoline, N-methylmorpholine and triethylamine. Moreover, you may use 1 type or mixture of 2 or more types as needed. Among these, a mixture system of γ-valerolactone and pyridine and a non-catalyst are particularly preferred from the viewpoint of reducing the height of reactivity and the effect on the next reaction.

The addition amount of the imidization catalyst is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, relative to 100 parts by mass of polyamic acid.

Reaction solvents used in the synthesis of the polyimide moiety include dimethyl ether, diethyl ether, methyl ethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. An ether compound having 2 to 9 carbon atoms; Ketone compounds having 2 to 6 carbon atoms, such as acetone and methyl ethyl ketone; Saturated hydrocarbon compounds having 5 to 10 carbon atoms, such as normal pentane, cyclopentane, normal hexane, cyclohexane, methylcyclohexane and decalin; Aromatic hydrocarbon compounds having 6 to 10 carbon atoms, such as benzene, toluene, xylene, mesitylene and tetralin; Ester compounds having 3 to 12 carbon atoms, such as methyl acetate, ethyl acetate, γ-butyrolactone and methyl benzoate; Halogen-containing compounds having 1 to 10 carbon atoms, such as chloroform, methylene chloride and 1,2-dichloroethane; Nitrogen-containing compounds having 2 to 10 carbon atoms, such as acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone; And sulfur-containing compounds such as dimethyl sulfoxide. These may be used alone or as a mixed solvent of two or more kinds, if necessary. Particularly preferred solvents include ether compounds having 2 to 9 carbon atoms, ester compounds having 3 to 12 carbon atoms, aromatic hydrocarbon compounds having 6 to 10 carbon atoms, and nitrogen-containing compounds having 2 to 10 carbon atoms. have. These can be arbitrarily selected considering industrial productivity and effects on the next reaction.

In the synthesis of the polyimide portion, the reaction temperature is preferably 15°C or higher and 250°C or lower. When the reaction temperature is 15°C or higher, the reaction starts, and if it is 250°C or lower, there is no deactivation of the catalyst. The reaction temperature is preferably 20°C or higher and 220°C or lower, and more preferably 20°C or higher and 200°C or lower.

Although the time required for the reaction varies depending on the purpose and the reaction conditions, it is usually within 96 hours, particularly preferably in the range of 30 minutes to 30 hours.

(Process 2)

Next, a process for synthesizing the polyamic acid portion in the second step will be described. Synthesis of the polyamic acid portion in the second step can be carried out by using the polyimide portion obtained in step 1 as a starting material and further adding diamine and/or acid dianhydride to polymerize it. The polymerization temperature at the time of synthesis of the polyamic acid portion in the second step is preferably 0°C or more and 250°C or less, more preferably 0°C or more and 100°C or less, and particularly preferably 0°C or more and 80°C or less.

Although the time required for the reaction in the synthesis of the polyamic acid varies depending on the purpose or reaction conditions, it is usually within 96 hours, particularly preferably in the range of 30 minutes to 30 hours.

As the reaction solvent, the same one used for the synthesis of the polyimide portion in Step 1 can be used. In that case, the polyamic acid portion can be synthesized using the reaction solution of step 1 as it is. Further, a solvent different from that used for the synthesis of the polyimide portion may be used.

The prepared polyimide precursor may be used dissolved in a reaction solvent, or may be recovered and purified by the following method. The polyimide precursor can be recovered after completion of production by distilling off the solvent in the reaction solution under reduced pressure.

As a method of purifying the polyimide precursor, a method of removing undissolved acid dianhydride and diamine in the reaction solution by vacuum filtration, pressure filtration, or the like can be mentioned. Further, a so-called reprecipitation purification method in which the reaction solution is precipitated in addition to the poor solvent may be carried out. In addition, when a high-purity polyimide precursor is required, a purification method by extraction using supercritical carbon dioxide is also possible.

(B) polymerizable compound

The photosensitive resin composition in this embodiment contains the polymerizable compound which has an unsaturated double bond. The polymerizable compound having an unsaturated double bond in the present embodiment contains a polymerizable unsaturated functional group such as a vinyl group, an allyl group, an acryloyl group, and a methacryloyl group, and among these, a conjugated vinyl group and acryl It is preferred from the viewpoint of polymerizability to have a diary and methacryloyl group. Moreover, as a number of polymerizable unsaturated functional groups in a polymerizable compound, it is preferable that it is two or more from a polymerizable viewpoint. In this case, the polymerizable unsaturated functional group may not necessarily be the same functional group. Moreover, as a molecular weight of a polymerizable compound, 100-5000 are preferable. In particular, when the molecular weight is in the range of 60 to 2500, compatibility with an alkali-soluble resin is good, and storage stability is excellent.

The compound having an unsaturated double bond according to the present embodiment contributes to the property that the solubility of the photosensitive resin composition in the alkali developer is changed by changing the structure by light irradiation. In the photosensitive resin composition according to the present embodiment, by including a compound having an unsaturated double bond and a photopolymerization initiator, a crosslinked body is formed by light irradiation, so that developer resistance and blocking and transport metals in the solder reflow furnace The stickiness is improved.

As a compound having an unsaturated double bond, tricyclodecane dimethylol diacrylate, ethylene oxide (EO) modified bisphenol A dimethacrylate, EO modified hydrogenated bisphenol A diacrylate, 1,6-hexanediol (meth)acrylic Rate, 1,4-cyclohexanediol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 2-di(p-hydroxyphenyl)propanedi(meth) Acrylate, tris(2-acryloxyethyl)isocyanurate, ε-caprolactone modified tris(acryloxyethyl)isocyanurate, glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, Polyoxypropyl trimethylolpropane tri(meth)acrylate, polyoxyethyl trimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, trimethylolpropane triglycidyl ether (meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, β-hydroxypropyl-β'-(acryloyloxy)-propylphthalate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth) Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol penta/hexa(meth)acrylate, and the like. Among them, EO-modified bisphenol A dimethacrylate, EO-modified hydrogenated bisphenol A diacrylate, and pentaerythritol tri/tetra (meth)acrylate are preferred from the viewpoint of developability and warpage after firing. These may be used alone or in combination of two or more.

As a particularly preferred form of the compound having an unsaturated double bond, it is preferable to include the (di)pentaerythritol (meth)acrylate ester compound from the viewpoint of blocking and adhesion to the transport metals in the solder reflow furnace. Moreover, the (di)pentaerythritol (meth)acrylate ester compound means a dipentaerythritol methacrylate ester compound, a dipentaerythritol acrylate ester compound, a pentaerythritol methacrylate ester compound, and a pentaerythritol acrylate ester compound. .

(D) As a pentaerythritol (meth)acrylate ester compound, pentaerythritol tri/tetraacrylate (trade name: Aaronix (registered trademark) M-303, 305, 306, 450, 452 manufactured by Toa Synthetic), pentaerythritol tetra Acrylate (trade name: A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated pentaerythritol tetraacrylate (trade name: SARTOMER SR-494, manufactured by Satmer), dipentaerythritol penta/hexaacrylate (trade name: Aaronix M -400, 402, 403, 404, 405, 406, manufactured by Toa Synthetic Co.) and the like.

The amount of the (meth)acrylate compound having two or more photopolymerizable unsaturated double bonds, when the amount of the polyimide precursor is 100 parts by mass, is preferably 5 parts by mass or more and 100 parts by mass or less, and 10 parts by mass from the viewpoint of developability. More than 80 parts by mass is more preferable.

(C) Photopolymerization initiator

The photopolymerization initiator according to the present embodiment is represented by the following formula (1).

*

(In formula (1), Ar ₁ is a monovalent organic group comprising aromatics, R ₁ is an organic group having an alkyl group or an aryl group, R ₂ is a branched chain alkyl group, a straight chain alkyl group, an alkyl group having an alicyclic structure, Or it is a monovalent hydrocarbon group having 3 to 50 carbon atoms, which is any of the alkyl groups having an aromatic structure.)

The photopolymerization initiator in this embodiment contributes to the property that the solubility of the photosensitive resin composition in the alkali developer is changed by generating a radical by light irradiation and polymerizing a compound having an unsaturated double bond.

In particular, since R ₂ is a long chain alkyl group, a branch chain alkyl group, an alkyl group having an aromatic structure, or an alkyl group having an alicyclic structure, it has a hydrophobic or bulky skeleton, and thus has good compatibility with a compound having an unsaturated double bond. The polymerization reactivity is improved. In particular, by combining with a compound having an unsaturated double bond having a quaternary carbon, such as a (di)pentaerythritol (meth)acrylate ester compound, it exhibits a remarkable effect, is highly sensitive, and has excellent wiring coverage even when the photosensitive resin composition is thin Expresses sex. From the viewpoint of polymerization reactivity, R ₂ is preferably an alkyl group having an alicyclic structure, and more preferably an alkyl group having an alicyclic structure having 5 to 7 carbon atoms.

By having a monovalent organic group comprising aromatics as Ar ₁ , it exhibits high photosensitivity from the i-line (365 nm) to the g-line (436 nm), which is an exposure wavelength widely used industrially as a photolithography technique. At this time, the visibility of the exposed portion is improved by selecting a long chain alkyl group, a branch chain alkyl group, an alkyl group having an aromatic structure, or an alkyl group having an alicyclic structure as R ₂ .

In addition, in the photopolymerization initiator according to the present embodiment, it is preferable that R ₂ in the formula (1) has a structure represented by the formula (2).

(In Formula (2), R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are hydrogen or an alkyl group having 1 to 20 carbon atoms, and may be the same or different respectively. n is an integer from 0 to 20 , m is an integer from 0 to 20.)

In this case, since R ₂ is composed of an alkyl group having an alicyclic structure, a bulky skeleton having hydrophobicity is introduced into R ₂ , and the above-described effect is further improved. In the above formula (2), a structure in which some of a plurality of R ₆ and R ₇ are independently alkyl groups having 1 to 20 carbon atoms, such as one R ₆ is a methyl group, and other R ₆ and R ₇ are hydrogen It is assumed that the phosphorus structure is also included.

Moreover, in the photosensitive resin composition which concerns on this embodiment, it is preferable that Ar<_1> of formula (1) is a structure represented by the following formula (3) substituted or unsubstituted or the following formula (4) substituted or unsubstituted. . In this case, the structures of the formulas (3) and (4) include both hydrogens in the aromatic groups in the formulas (3) and (4) substituted with other substituents and unsubstituted ones. It is assumed.

(In formula (3), X is a monovalent organic group, and R ₈ is a substituted or unsubstituted furyl group, thienyl group, or phenyl group.)

The amount of the photopolymerization initiator is preferably 0.01 parts by mass or more and 40 parts by mass or less, more preferably 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyimide precursor, from the viewpoints of photosensitivity and lithography characteristics.

The photopolymerization initiator according to the present embodiment can also be used in combination with other known photopolymerization initiators. Other known photopolymerization initiators include benzyl dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethan-1-one, benzyl dipropyl ketals, benzyl diphenyl ketals, and benzoin methyl ethers. , Benzoin ethyl ether, thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, 4-isopropyl thioxanthone, 2,4-iso Propyl thioxanthone, 2-fluorothioxanthone, 4-fluorothioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 1-chloro-4-propoxyxanthoxone, benzophenone, 4, Aromatic ketone compounds such as 4'-bis(dimethylamino)benzophenone [Mihila ketone], 4,4'-bis(diethylamino)benzophenone, 2,2-dimethoxy-2-phenylacetophenone, and the amount of roffin Triarylimidazole dimers such as sieve, acridine compounds such as 9-phenylacridine, α,α-dimethoxy-α-morpholino-methylthiophenylacetophenone, 2,4,6-trimethyl Oxime ester compounds such as benzoyldiphenylphosphine oxide and N-aryl-α-amino acids, p-dimethylaminobenzoic acid, p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid, p-diisopropylaminobenzoic acid, p-benzoic acid Ester, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy -2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one Α-hydroxyalkylphenones such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl) Α-aminoalkylphenones such as methyl]-1-[4-(4-morphonyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4 And acylphosphine oxides such as ,6-trimethylbenzoyl)-phenylphosphine oxide, sulfonium salt-based photocationic polymerization initiator, and iodonium salt-based photocationic polymerization initiator. These may be used alone or in combination of two or more.

In order to improve the thermal stability and storage stability of the photosensitive composition of the present embodiment, a polymerization inhibitor may also be included. Such polymerization inhibitors include, for example, p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert.-butylcatechol, cuprous chloride, 2,6-di-tert.-butyl-p-cresol, And 2,2'-methylenebis(4-ethyl-6-tert.-butylphenol) and 2,2'-methylenebis(4-methyl-6-tert.-butylphenol).

(D) nitroso compounds and/or nitro compounds

In the photosensitive composition according to the present embodiment, it is particularly preferable to include at least one nitroso compound and/or nitro compound as a polymerization inhibitor used for thermal stability. The nitroso compound and/or the nitro compound is one containing a nitroso group and/or a nitro group in the structural formula.

Examples of nitroso compounds include nitroso aromatics such as nitrosobenzene, nitrosotoluene, p-nitrosophenol, nitrosoresorcinol, 1-nitrso-2-naphthol, and 2-nitrso-1-naphthol. Hydrocarbon and N-nitrosodiphenylamine, N-nitroso-N-methylaniline, N-nitroso-N-phenylaniline, N-nitrosophenylhydroxylamine, N-nitrosophenylhydroxylamine salt (metal salt, And N-nitrosos such as ammonium salts).

Further, examples of the nitro compound include o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, 2,4-dinitrochlorobenzene, 1,5-dinitronaphthalene, and 2,4-dinitro. -1-naphthol, 2,4-dinitrophenol, 2,5-dinitrophenol, 2,4-dinitro-6-secondary-butyl-phenol, 4,6-dinitro-o-cresol and 1 And nitro aromatic compounds such as ,3,5-trinitrobenzene.

Among these, N-nitrosophenylhydroxylamine ammonium salt, N-nitrosophenylhydroxylamine aluminum salt, and 2,4-dinitrophenol are preferable in view of the ability to inhibit polymerization and ease of availability.

The addition amount of the polymerization inhibitor is preferably 1 ppm to 100000 ppm, more preferably 100 ppm to 10000 ppm with respect to the mass of the alkali-soluble resin. Moreover, it is preferable that it is 1 ppm or more from a viewpoint of fully exhibiting a polymerization inhibitory effect, and it is preferable that it is 100000 ppm or less from a viewpoint of maintaining photosensitivity.

In the present embodiment, in order to further improve the polymerization preventing effect, a polymerization inhibitor composed of a nitroso compound and/or a nitro compound may be coexisted with another polymerization inhibitor in a range that does not significantly impair the photosensitivity. Examples of such other polymerization inhibitors include p-tert-butyl catechol, hydroquinone, and p-methoxyphenol.

(E) Block isocyanate

In the resin composition in this embodiment, it is preferable to contain a block isocyanate from the viewpoint of preventing a metal conveying system at a high temperature furnace in a solder reflow process at the time of mounting a component or sticking to a metal jig. This blocked isocyanate is a compound obtained by reacting a blocking agent with an isocyanate having two or more isocyanate groups in a molecule.

As the isocyanate, for example, 1,6-hexane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4' -Dicyclohexylmethane diisocyanate, 4,4'-hydroxylate diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 4,4-diphenyl diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane , Phenylene 1,4-diisocyanate, phenylene 2,6-diisocyanate, 1,3,6-hexamethylene triisocyanate and hexamethylene diisocyanate.

Blocking agents include, for example, alcohols, phenols, ε-caprolactam, oximes, active methylenes, mercaptans, amines, imides, acidamides, imidazoles, urea, carbamates, imines and sulfites Ryu is mentioned.

As specific examples of the block isocyanate, trade names of Duranate SBN-70D, TPA-B80E, TPA-B80X, 17B-60PX, MF-B60X, E402-B80T, ME20-B80S, MF-K60X and K6000 manufactured by Asahi Kasei Chemical Co., Ltd. Hexamethylene diisocyanate (hereinafter also referred to as "HDI") block isocyanates, such as Mitsui Chemical Polyurethane brand name Takenate B-882N, Tolylene diisocyanate type block isocyanate, brand name Takenate B-830, 4,4' -Diphenylmethane diisocyanate-based block isocyanate, trade names Takenate B-815N and 1,3-bis(isocyanatemethyl)cyclohexane-based block isocyanate Takenate B-846N, manufactured by Nihon Polyurethane Co., Ltd., Colonon AP-M , 2503, 2515, 2507, 2513 and milionate MS-50, and the like, isophorone diisocyanate-based block isocyanate, Baxenden, product number 7950, 7951, 7990. These blocked isocyanates may be used alone or in combination of two or more.

Moreover, in this embodiment, although the example using block isocyanate as a polyfunctional isocyanate was demonstrated, it is also possible to use the polyfunctional isocyanate which has two or more isocyanate groups in the range which shows the effect of this embodiment.

(F) phosphorus compound

In the resin composition in this embodiment, it is preferable to contain a phosphorus compound from a viewpoint of improving the flame retardance of the resin composition. As the phosphorus compound, it is particularly preferable to include a phosphazene compound. Accordingly, the flame retardancy of the resin composition is particularly improved. Moreover, a phosphazene compound is a compound which has a phosphazene structure in a molecule|numerator. Further, as the phosphorus compound, one type of phosphorus compound may be used, or two or more types of phosphorus compounds may be used in combination.

As a phosphazene compound, what has a structure represented by following formula (8) and following formula (9), etc. are mentioned.

R ₂₇ , R ₂₈ , R ₂₉ and R ₃₀ in the formula (8) and the formula (9) are not limited as long as they are organic groups having 1 to 20 carbon atoms. If it is 1 or more carbon atoms, it is preferable because flame retardancy tends to be expressed. When it is 20 or less, it is preferable because it tends to be compatible with alkali-soluble resins.

As R ₂₇ , R ₂₈ , R ₂₉ and R ₃₀ , a functional group derived from an aromatic compound having 6 to 18 carbon atoms is particularly preferred from the viewpoint of flame retardant expression. As such a functional group, for example, a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-hydroxyphenyl group, 3-hydroxyphenyl group, 4-hydroxyphenyl group, 2-cyanophenyl group, 3- Functional groups having a phenyl group such as a cyanophenyl group or 4-cyanophenyl group, functional groups having a naphthyl group such as 1-naphthyl group, 2-naphthyl group, and nitrogen-containing heterocyclic compounds such as pyridine, imidazole, triazole, tetrazole And functional groups derived from. The compounds having these functional groups may be used alone or in combination of two or more kinds, if necessary. Among these, compounds having a phenyl group, 3-methylphenyl group, 4-hydroxyphenyl group, and 4-cyanophenyl group are preferred for ease of availability.

V in the phosphazene compound represented by the formula (8) is not limited as long as it is 3 or more and 25 or less. If V is 3 or more, flame retardancy is exhibited, and if it is 25 or less, solubility in organic solvents is improved. Especially, it is preferable that V is 3 or more and 10 or less because of availability.

W in the phosphazene compound represented by the formula (9) is not limited as long as it is 3 or more and 10000 or less. If it is 3 or more, flame retardance is expressed, and if it is 10000 or less, solubility in an organic solvent is high. Especially, 3 or more and 100 or less are preferable because of availability.

G and J in the phosphazene compound represented by the formula (9) are not limited as long as they are organic groups having 3 to 30 carbon atoms. Among them, G is -N=P(OC ₆ H ₅ ) ₃ , -N=P(OC ₆ H ₅ ) ₂ (OC ₆ H ₄ OH), -N=P(OC ₆ H ₅ )(OC ₆ H ₄ OH) ₂ , -N=P(OC ₆ H ₄ OH) ₃ , -N=P(O)(OC ₆ H ₅ ), -N=P(O)(OC ₆ H ₄ OH), etc. Do. J is -P(OC ₆ H ₅ ) ₄ , -P(OC ₆ H ₅ ) ₃ (OC ₆ H ₄ OH), -P(OC ₆ H ₅ ) ₂ (OC ₆ H ₄ OH) ₂ , -P (OC ₆ H ₅ )(OC ₆ H ₄ OH) ₃ , -P(OC ₆ H ₄ OH) ₄ , -P(O)(OC ₆ H ₅ ) ₂ , -P(O)(OC ₆ H ₄ OH ) ₂ , -P(O)(OC ₆ H ₅ )(OC ₆ H ₄ OH), and the like.

The addition amount of the phosphorus compound is preferably 50 parts by mass or less with respect to 100 parts by mass of the alkali-soluble resin from the viewpoint of developability and the like, and more preferably 45 parts by mass or less from the viewpoint of flame retardancy of the cured product of the photosensitive resin composition. Moreover, flame retardance improves if the addition amount is 5 mass parts or more.

(G) Other compounds

In the resin composition in the present embodiment, other compounds may be included within a range that does not adversely affect the performance. As other compounds, specifically, compounds having reactivity with alkali-soluble resins, such as thermosetting resins and polyimide precursors, used to improve the toughness, solvent resistance, and heat resistance (thermal stability) of the film after firing, to improve adhesion And coloring materials such as pigments and dyes used for coloring the films obtained by using the heterocyclic compounds and photosensitive resin compositions used.

Examples of the thermosetting resin include epoxy resins, cyanate ester resins, unsaturated polyester resins, benzoxazine resins, benzooxazolines, phenol resins, melamine resins, and maleimide compounds.

Examples of the compound having reactivity with the alkali-soluble resin include a carboxyl group and an amino group in the polymer, a compound that reacts with a terminal having a structure derived from an acid anhydride to form a three-dimensional crosslinked structure, and the like. Among these, a so-called heat base generator, which is a compound that generates an amino group that is a base by heating, is preferable. Examples of the heat base generator include compounds obtained by forming a salt structure between an amino group of a base compound such as an amine and an acid such as sulfonic acid to protect it as a dicarbonate compound or an acid chloride compound. For this reason, the heat base generator is stable because no basicity is expressed at room temperature, and can be deprotected by heating to generate a base.

The heterocyclic compound is not limited as long as it is a cyclic compound containing a hetero atom. Examples of the hetero atom include oxygen, sulfur, nitrogen and phosphorus. As the heterocyclic compound, for example, imidazole such as 2-methylimidazole, 2-undecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1,2-dimethyl N-alkyl group substituted imidazole such as imidazole, 1-cyanoethyl-2-methyl containing aromatic groups such as 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole Cyanides such as imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole Imidazole compounds such as silicon-containing imidazoles such as nogi-containing imidazole and imidazolesilane, 5-methylbenzotriazole, 1-(1',2'-dicarboxyethylbenzotriazole), and 1-(2-ethyl Triazole compounds such as hexaminomethylbenzotriazole) and oxazole compounds such as 2-methyl-5-phenylbenzoxazole.

As the coloring material, for example, phthalocyanine-based compounds such as phthalocyanine green, fuchsin, auramin base, chalcocide green S, paramagenta, crystal violet, methyl orange, nile blue 2B, Victoria blue, malachite green, basic blue 20 and diamond Green is mentioned.

Moreover, as a coloring material, the coloring-type dye which colors by light irradiation can also be used. As such a color-based dye, there is a combination of a leuco dye or a fluorane dye and a halogen compound. Examples of such a combination include tris(4-dimethylamino-2-methylphenyl)methane [leuco crystal violet] and tris(4-dimethylamino-2-methylphenyl)methane [leuco malachite green]. Examples of the halogen compound include amyl bromide, amyl bromide, isobutyl bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, tris(2,3-di Bromopropyl)phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, hexachloroethane and triazine compounds. have. Triazine compounds include, for example, 2,4,6-tris(trichloromethyl)-s-triazine and 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-tri Ajin can be mentioned.

The addition amount of other compounds is not limited as long as it is 0.01 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the alkali-soluble resin. When the amount added is 0.01 part by mass or more, the added effect tends to be sufficiently exhibited, and if it is 30 parts by mass or less, the photosensitive effect is not adversely affected.

In the photosensitive resin composition in this embodiment, you may further contain an organic solvent. The organic solvent is not limited as long as it is capable of uniformly dissolving and/or dispersing the alkali-soluble resin. Examples of such organic solvents include ethers having 2 or more carbon atoms and 9 or less carbon atoms, such as dimethyl ether, diethyl ether, methyl ethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. compound; Ketone compounds having 2 to 6 carbon atoms, such as acetone and methyl ethyl ketone; Saturated hydrocarbon compounds having 5 to 10 carbon atoms, such as normal pentane, cyclopentane, normal hexane, cyclohexane, methylcyclohexane and decalin; Aromatic hydrocarbon compounds having 6 to 10 carbon atoms, such as benzene, toluene, xylene, mesitylene and tetralin; Ester compounds having 3 to 9 carbon atoms, such as methyl acetate, ethyl acetate, γ-butyrolactone and methyl benzoate; Halogen-containing compounds having 1 to 10 carbon atoms, such as chloroform, methylene chloride and 1,2-dichloroethane; Nitrogen-containing compounds having 2 to 10 carbon atoms, such as acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone; And sulfur-containing compounds such as dimethyl sulfoxide.

These may be used alone or as a mixed solvent of two or more, if necessary. Particularly preferred organic solvents include ether compounds having 2 to 9 carbon atoms, ester compounds having 3 to 9 carbon atoms, aromatic hydrocarbon compounds having 6 to 10 carbon atoms, and nitrogen-containing compounds having 2 to 10 carbon atoms and these. And two or more kinds of mixed solvents. Further, from the viewpoint of solubility of the alkali-soluble resin, triethylene glycol dimethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, and N,N-dimethylacetamide are preferable. Do.

In the resin composition composed of an alkali-soluble resin and an organic solvent, the concentration of the alkali-soluble resin is not particularly limited as long as it is a concentration capable of forming a resin molded body. From the viewpoint of the film thickness of the resin molded body to be produced, the concentration of the alkali-soluble resin is preferably 1 mass% or more, and from the viewpoint of uniformity in the film thickness of the resin molded body, the concentration of the alkali-soluble resin is preferably 90 mass% or less, and 2 mass % Or more and 80 mass% or less is more preferable.

<Photosensitive film laminate>

The photosensitive resin composition according to the present embodiment can be preferably used for forming a photosensitive film. By setting it as the product form of a photosensitive film, compared with the liquid product form, the drying and volatilization process of the solvent in a printed wiring board production site becomes unnecessary, and the working environment is improved. In addition, since both sides can be simultaneously processed, it contributes to productivity improvement. In addition, there is an advantage that can easily produce a product having excellent surface smoothness of the cover material on the wiring. The photosensitive film layered product which concerns on this embodiment has a base material and the photosensitive film containing the photosensitive resin composition formed on this base material. In addition, in the photosensitive film layered product which concerns on this embodiment, the photosensitive film which contains the base material, the said photosensitive resin composition formed on this base material, and the antifouling or protective cover film formed on this photosensitive resin is provided. It is preferable to use a film laminate.

The base material is not limited as long as it is a base material that does not damage the photosensitive film at the time of forming the photosensitive film laminate. Examples of such substrates include silicon wafers, glass, ceramics, heat-resistant resins, and carrier films. Among these, it is preferable that it is a carrier film from a viewpoint of suitability in a roll-to-roll production system and ease of handling.

As a carrier film, it is preferable that it is transparent which transmits ultraviolet active light. Examples of the carrier film that transmits ultraviolet active light include, for example, polyethylene terephthalate (PET) film, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride copolymer film, poly And methyl methacrylate copolymer films, polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films, and cellulose derivative films. Among these, it is preferable that it is a PET film from a viewpoint of peelability after circuit board crimping and exposure. As these films, those drawn as necessary can also be used. Although the thickness of these films is advantageous in terms of image formability and economical efficiency, it is generally 10 to 30 µm in view of the need to maintain strength.

The cover film is not limited as long as it is a film that protects the photosensitive film obtained using a photosensitive resin composition such as low density polyethylene.

Next, a method of manufacturing the photosensitive film laminate will be described. When manufacturing a photosensitive film laminated body using a photosensitive resin composition, the solution of a photosensitive resin composition is apply|coated on arbitrary base materials by arbitrary methods. Next, after drying and drying a photosensitive resin composition, it is set as the photosensitive film laminated body which has a carrier film and a photosensitive film, for example. For coating the photosensitive resin composition onto the substrate, for example, a coat method such as a bar coat, roller coat, die coat, blade coat, dip coat, doctor knife, spray coat, flow coat, spin coat, slit coat, and brushing can be used. Can be. After coating, if necessary, a heat treatment such as prebaking may be performed by a hot plate or the like.

<flexible printed wiring board>

The photosensitive film which concerns on this embodiment can be used suitably for manufacture of a flexible printed wiring board. The flexible printed wiring board according to the present embodiment includes a circuit board having wiring, and the photosensitive film formed to cover the wiring on the circuit board and fired. The wiring is, for example, a copper wiring, but is not particularly limited. This flexible printed wiring board can be obtained by pressing a photosensitive film on a circuit board having wiring to perform alkali development, followed by baking. At this time, it is preferable from the viewpoint of a method for efficiently mass-producing a flexible printed wiring board after laminating the photosensitive film on a wiring surface on a circuit board having wiring by using a roll-type thermal vacuum laminator.

1 is an explanatory view showing a minimum thickness and a surface level difference of the flexible printed wiring board according to the present embodiment. In Fig. 1, reference numeral 11 denotes a circuit board, reference numeral 12 denotes a fired photosensitive film, and reference numeral 13 denotes wiring. In the flexible printed wiring board 10 according to the present embodiment, it is preferable that the minimum thickness (a) of the plastically formed photosensitive film 12 on the wiring 13 is 0.1 μm or more and 10 μm or less, and 1 μm or more and 8 It is more preferable that it is µm or less, and more preferably 2 µm or more and 5 µm or less. (a) is preferably 0.1 µm or more from the viewpoint of preventing oxidation of the wiring 13 and insulation reliability, and preferably 10 µm or less from the viewpoint of preventing crack generation during bending.

Moreover, the minimum thickness (a) of the photosensitive film 12 fired and formed on the wiring 13 can be obtained by observing the surface of the flexible printed wiring board 10 polished in the thickness direction with an optical microscope. Specifically, the ratio of the distance (L/S) between the copper wiring pattern and the copper wiring pattern gap is 1:5 or less, and the wirings 13 arranged in parallel to five or more are vertically polished to them, and both ends of the copper wiring pattern are The average value of the minimum thickness of the photosensitive film 12 on three or more parallel wirings 13 in the center excluded is measured, and the average value of the measured values of five or more locations is defined as (a).

In addition, in the portion of the wiring 13 and the portion without the wiring 13, the maximum value (b) of the surface step difference of the photosensitive film 12 is preferably 10 μm or less, more preferably 6 μm or less, and more preferably 3 μm. It is more preferable that it is the following.

In addition, the maximum value (b) of the surface step is measured when the distance from the surface of the circuit board 11 to the surface of the photosensitive film 12 is measured, the distance b1 on the wiring 13 and the wiring 13 The difference in the distance b2 of the portion without this is shown. The maximum value (b) of the surface level difference can be obtained by observing the surface polished by the flexible printed wiring board 10 in the thickness direction with an optical microscope.

Specifically, the ratio of the gap (L/S) between the copper wiring pattern and the copper wiring pattern is 1:5 or less, and the wirings 13 arranged in five or more are vertically polished. Next, the distance b1 from the surface of the circuit board 11 of the portion farthest from the surface of the circuit board 11 of the photosensitive film 12 on the copper wiring 13 is measured. Further, the distance b2 from the surface of the circuit board 11 of the portion closest to the surface of the circuit board 11 of the photosensitive film 12 of the portion without the copper wiring 13 is measured. Find the difference between (b1)-(b2). Five or more differences were measured, and the average value was defined as (b).

Examples of the circuit board having wiring in the flexible printed wiring board include a rigid substrate such as a glass epoxy substrate and a glass maleimide substrate, and a flexible substrate such as a copper-clad laminate. Among them, a flexible substrate is preferred from the viewpoint of being bendable.

The method for manufacturing the flexible printed wiring board is not particularly limited as long as the photosensitive film is formed on the circuit board so as to cover the wiring. Examples of such a manufacturing method include a method of performing heat press, thermal lamination, thermal vacuum press, thermal vacuum lamination, etc. in a state in which the wiring side of a circuit board having wiring is brought into contact with the photosensitive film laminate according to the present embodiment. Can. Among them, from the viewpoint of embedding the photosensitive film between the wires, the hot vacuum press method and the hot vacuum laminate method are preferred.

The heating temperature when laminating a photosensitive film laminate on a circuit board having wiring is not limited as long as the temperature is such that the photosensitive film can be in close contact with the circuit board. From the viewpoint of adhesion to the circuit board, or from the viewpoint of decomposition or side reaction of the photosensitive film, 30°C or more and 400°C or less are preferable. More preferably, it is 50°C or more and 150°C or less.

The front surface treatment of the circuit board having wiring is not particularly limited, and examples thereof include hydrochloric acid treatment, sulfuric acid treatment, and sodium persulfate aqueous solution treatment.

The photosensitive film layered product can be negative-type photolithography by selecting the light-irradiated portion with an arbitrary photomask and then dissolving the light-irradiated portion other than the light-irradiated portion with an alkali phenomenon. In this case, it is preferable to irradiate light after the circuit board has been brought to room temperature. In addition, it is preferable from the viewpoint of peeling off the carrier film after light irradiation and performing alkali development treatment to prevent the radicals generated by the photopolymerization initiator (C) from being deactivated by the effect of oxygen inhibition and to improve the stability of the photosensitivity. . As a light source used for light irradiation, a high pressure mercury lamp, an ultra high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a xenon lamp, a fluorescent lamp, a tungsten lamp, an argon laser, and a helium cadmium laser are mentioned. Among them, a high pressure mercury lamp and an ultra high pressure mercury lamp are preferable.

The alkali aqueous solution used for development is not limited as long as it is a solution that can dissolve other than the light irradiation site. Examples of such a solution include an aqueous sodium carbonate solution, an aqueous potassium carbonate solution, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and an aqueous tetramethylammonium hydroxide solution. From the viewpoint of developability, an aqueous sodium carbonate solution and an aqueous sodium hydroxide solution are preferred. Examples of the development method include spray development, immersion development, and puddle development. If necessary, a water washing treatment or a drying treatment can also be performed.

Next, a flexible printed wiring board is obtained by firing the printed wiring board on which the photosensitive film is pressed. The calcination is preferably performed at a temperature of 30°C or higher and 400°C or lower, and more preferably 100°C or higher and 300°C or lower, from the viewpoint of solvent removal, side reaction and decomposition.

The reaction atmosphere in firing can be carried out in an air atmosphere or in an inert gas atmosphere. In the production of the printed wiring board, the time required for firing varies depending on the reaction conditions, but is usually within 24 hours, particularly preferably in the range of 1 hour to 8 hours.

The photosensitive film laminate using the photosensitive film according to the present embodiment has good curvature after curing, has good developability, and exhibits chemical resistance when used as a cured body. Printed wiring boards used, protective layer formation on circuit boards, insulation layer formation on laminated boards, silicon wafers used in semiconductor devices, semiconductor chips, members around semiconductor devices, substrates for mounting semiconductors, heat sinks, lead pins, semiconductors themselves, etc. It is used for film formation for electronic components for use in protection or insulation and adhesion of.

In addition, the photosensitive film laminate using the photosensitive film according to the present embodiment includes a substrate for a flexible printed wiring circuit (FPC), a substrate for tape automation bonding (TAB), an electrical insulating film and a substrate for liquid crystal displays in various electronic devices, and an organic It can also be used for substrates for electroluminescent (EL) displays, substrates for electronic paper, substrates for solar cells, and is particularly preferably used as a coverlay that is a protective film for protecting silicon wafers, copper-clad laminates, flexible printed wiring circuits, and the like. Can be.

Example

Hereinafter, examples performed to clarify the effects of the present invention will be described, but the present invention is not limited at all by these examples. In addition, measurement methods and definitions of various properties and properties in Examples are as follows.

<Reagent>

The reagents used in Examples and Comparative Examples are as follows. In the following Examples 1 to 10 and Comparative Examples 1 to 7, abbreviations of the following reagents are appropriately indicated.

(A) alkali-soluble resin component

BPDA (manufactured by Mitsui Chemicals)

APB (brand name: APB-N, manufactured by Mitsui Chemicals)

Diamine: polyetheramine represented by formula (5) (trade name: polyetheramine D-400 (hereinafter simply referred to as "D-400"), manufactured by BASF, m+n+p=6.1)

Jeffamine (trade name: Jeffamine D-230 (hereinafter simply referred to as "D-230"), manufactured by Huntsman, m+n+p=2.5)

Methacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

Methyl methacrylate (monomer, manufactured by Wako Pure Chemical Industries, Ltd.)

Styrene (monomer, manufactured by Wako Pure Chemical Industries, Ltd.)

2,2'-Azobisisobutyronitrile (AIBN, manufactured by Wako Pure Chemical Industries, Ltd.)

(B) Compound having an unsaturated double bond

EO-modified bisphenol A dimethacrylate (Brand name: BPE-500, manufactured by Shin-Nakamura Chemical Co., Ltd.)

Ethoxylated pentaerythritol tetraacrylate (trade name: SARTOMER SR-494 (hereinafter simply referred to as "SR-494"), manufactured by Sartomer Corporation)

Trimethylolpropane PO-modified triacrylate (brand name: Aaronix M-310 (hereinafter simply referred to as "M-310"), manufactured by Toa Synthetic Corporation)

(C) Photopolymerization initiator

1,2-propanedione-3-cyclopentyl-1-[4-(phenylthio)phenyl]-2-(O benzoyloxime) (brand name: PBG-305, manufactured by Sangju Strong Electronics Co., Ltd.)

3-cyclopentylpropanone-1-(6-2-formylthiophen-9-ethylcarbazol-3-yl)-1-oxime acetate (trade name: PBG-314, manufactured by Sangju Strong Electronics Co., Ltd.)

3-Cyclopentylpropanone-1-(6-formylfuran-9-ethylcarbazol-3-yl)-1-oxime acetate (trade name: PBG-314F, manufactured by Changju Strong Synthetic Co., Ltd.)

3-cyclopentyl-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]propanone-1-(O-acetyloxime) (brand name: PBG-304, resident strength Electronics manufacturer)

Ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (trade name: IRGACURE OXE-02 (hereinafter simply referred to as ``OXE-02 ''), manufactured by Chiba Japan)

(D) polymerization inhibitor

N-nitrosophenyl hydroxylamine aluminum (brand name: Q-1301, manufactured by Wako Pure Chemical Industries, Ltd.)

N-nitrosophenyl hydroxylamine ammonium salt (brand name: Q-1300, manufactured by Wako Pure Chemical Industries, Ltd.)

p-methoxyphenol (manufactured by Wako Pure Chemical Industries, Ltd.)

(E) Block isocyanate

Block isocyanate (trade name: Duranate SBN-70D (hereinafter simply referred to as "SBN-70D"), manufactured by Asahi Kasei Chemicals)

(F) phosphorus compound

Phosphazene compound (trade name: FP-300, manufactured by Fushimi Pharmaceutical Co., Ltd.)

(G) Other compounds

Solvent Blue 70 (brand name: OIL BLUE 650, manufactured by Orient Chemical Industries, Ltd.)

Toluene (manufactured by Wako Pure Chemical Industries, for organic synthesis)

γ-butyrolactone (manufactured by Wako Pure Chemical Industries, Ltd.)

Methyl ethyl ketone (MEK, manufactured by Wako Pure Chemical Industries, Ltd.)

Sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.)

<Weight average molecular weight measurement>

Gel permeation chromatography (GPC), which is a method for measuring the weight average molecular weight, was measured according to the following conditions. As a solvent, N,N-dimethylformamide (manufactured by Wako Pure Chemical Industries, for high-speed liquid chromatography) was used, and 24.8 mmol/L lithium bromide monohydrate (wako Pure Chemical Industries, purity 99.5%) was used before measurement. And 63.2 mmol/L phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd. for high-speed liquid chromatography) was used. In addition, the calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).

Column: Shodex KD-806M (manufactured by Showa Denko)

Flow rate: 1.0 mL/min

Column temperature: 40℃

Pump: PU-2080Plus (manufactured by JASCO)

Detector: RI-2031Plus (RI: Differential refractometer, manufactured by JASCO)

UV-2075Plus (UV-VIS: ultraviolet visible absorber, manufactured by JASCO)

<Production method of photosensitive film laminate>

The coating method of the photosensitive resin composition was performed by a doctor blade method using FILM COATER (manufactured by TESTER SANGYO, PI1210). A photosensitive resin composition was added dropwise to a PET film (Teijin DuPont Film Co., G2, film thickness = 16 µm), coated to a thickness of 15 µm after drying, and then dried (SPHH-10l, manufactured by ESPEC). By drying at 95°C for 12 minutes, a photosensitive film laminate was obtained. The film thickness was measured using a film thickness meter (ID-C112B, manufactured by Mitutoyo).

<Method for producing lithographic pattern of photosensitive film>

On a flexible substrate (ESPANEX: MC12-20-00CEM, manufactured by Shinnitetsu Chemical Co., Ltd.), the migration test wiring according to Annex 2 to JPCA-2006-DG2 (conductor width/conductor gap is 50/50 µm, number of patterns is 10 ) And a beta copper foil portion (5 cm×5 cm) were formed.

Next, using a vacuum press machine (SA-501, manufactured by Tester Industries, Inc.), the press temperature was set to 80°C, a cylinder pressure of 0.5 MPa, and a press time of 30 seconds, and the photosensitive film laminate was laminated on the copper wiring surface of the test substrate.

Next, a photomask was placed to shield the electrode portion of the migration test wiring, and a step tablet (Stouffer21) was placed on the beta copper foil portion. Then, both were vacuum-contacted, followed by exposure to 200 mJ/cm 2 with an ultra-high pressure mercury lamp (HMW-201KB, manufactured by Oku Corporation). Thereafter, the PET film was peeled from the obtained laminate, and spray development treatment and rinsing with water were performed at 30° C. for 1.0 mass% sodium carbonate solution for 22 seconds, followed by drying to prepare a photolithographic pattern of the photosensitive film.

<Practical characteristics evaluation>

Practical characteristics were observed using a naked eye or a microscope during the lithography pattern production process of the photosensitive film, and the practical characteristics of the photosensitive film laminate were evaluated by its quality. ◎ or ○ was set as the pass for the following five evaluations.

(Evaluation of light sensitivity)

By the photolithography pattern, the number of steps and tablets in the part where the development was not removed and the copper surface was not completely exposed was observed.

◎: 9 or more

○: 7-8 steps

×: 6 or less

(Evaluation of visibility by the Ministry of Exposure)

Immediately after exposure through a photomask, the color difference between the exposed portion and the unexposed portion was visually observed under a yellow room environment.

◎: The exposed part and the unexposed part can be clearly identified.

○: The exposed portion and the unexposed portion can be distinguished.

×: The exposed portion and the unexposed portion cannot be distinguished

(Phenomenon residue evaluation)

The copper surface of the step and tablet, which was developed and removed and the copper surface was completely exposed by the photolithography pattern, was visually observed to compare the color tone of the untreated test substrate with the copper surface.

○: There is no difference in color tone of the copper surface.

X: The copper surface from which development was removed is discolored.

(Blocking evaluation)

A low-density polyethylene film (GF-858, thickness=35 um, manufactured by Tama Poly Co.) was bonded with a rubber roller so as to contact the photographic pattern surface after the development treatment. This was stored for 24 hours in an environment of 23°C and 50%RH, and peeling was tested at a peeling rate of 0.1 m/min and a peeling angle of 90°. As a measuring apparatus, a tensile tester (Tensilon RTM-500 manufactured by Orient Tech Co., Ltd.: load cell rating 1 Kgf) was used. The peeling test distance was 60 mm, and the lamination releasability after development was evaluated from the integral average weight when weighting was plotted against elongation.

◎: Integral average weight is less than 0.01 N/25 mm

○: Integral average weight is less than 0.01 to 0.1 N/25 mm.

×: integral average weight of 0.1 N/25 mm or more

(Evaluation of wiring coverage)

Migration test of photolithography pattern The state of the photosensitive film on the wiring was observed with an optical microscope (50 times).

○: No swelling or peeling of the photosensitive film on the wiring was observed.

X: The photosensitive film on the wiring is swelled, and the surface shape is observed in a wrinkled shape, or the photosensitive film on the wiring is peeled to expose the copper wiring.

(Evaluation of adhesion to metal jigs)

The obtained photolithography pattern was sandwiched between both sides of the SUS plate (150 mm×75 mm, thickness=0.5 mm, made of SUS304), and the surface temperature of the SUS plate was 260 using a firing furnace (NRY-325-5Z, manufactured by Yamato Works). It was fired in an air atmosphere on condition of maintaining at 30 DEG C for 30 seconds. After cooling to room temperature, the photolithography pattern was peeled from the SUS plate, and the transfer state to the SUS plate was visually observed.

◎: There is no transfer of the photosensitive film layer to the SUS plate.

○: A portion of the photosensitive film layer is melt-transferred to the SUS plate.

×: The photosensitive film layer was completely deposited on the SUS plate, and was not peeled off.

<Synthesis example>

(Alkali-soluble resin (A1))

Under a nitrogen atmosphere, in a separable flask equipped with a Dean-Stark apparatus and a reflux, γ-butyrolactone (255 g), toluene (51.0 g), polyetheramine D-400 (86.8 g (201.9 mmol)), BPDA (120 g (407.9 mmol)) was added, the temperature was raised to 180°C, and the mixture was heated and stirred at 180°C for 1 hour. After removing the azeotropic solvent toluene, the mixture was cooled to 40°C, and then APB-N (48.4 g (165.7 mmol)) was added and stirred at 40°C for 4 hours to obtain a solution of the polyimide precursor (A1). The weight average molecular weight of the obtained polyimide precursor (A1) was 23000.

(Alkali-soluble resin (A2))

Under nitrogen atmosphere, in a separable flask equipped with a Dean-Stark apparatus and a reflux, γ-butyrolactone (80.0 g), toluene (16.0 g), polyetheramine D-230 (16.8 g (73.04 mmol)), BPDA (30.0 g (102.0 mmol)) was added, the temperature was raised to 180°C, and the mixture was heated and stirred at 180°C for 1 hour. After removing the azeotropic solvent toluene, the mixture was cooled to 40°C, and APB-N (5.60 g (19.16 mmol)) was added thereto, followed by stirring at 40°C for 4 hours to obtain a solution of the polyimide precursor (A2). The weight average molecular weight of (A2) was 21000.

(Alkali-soluble resin (A3))

In a nitrogen atmosphere, in a separable flask equipped with a Dean-Stark apparatus and a reflux, 300 g of MEK, methacrylic acid (100 g), methyl methacrylate (200 g), and styrene (100 g) were added while stirring in a hot water bath. The temperature was raised to 70°C. Subsequently, 2 g of AIBN was dissolved in 30 g of MEK and added, followed by polymerization for 6 hours. In addition, 3 g of AIBN was dissolved in 30 g of MEK, added in two portions at intervals of 1 hour, and then the temperature in the flask was raised to the boiling point of the solvent, followed by polymerization at that temperature for 2 hours. After the polymerization was completed, 240 g of MEK was added and the polymerization reaction was taken out from the flask to obtain a solution of acrylic resin solution (A3). The weight average molecular weight of the obtained alkali-soluble acrylic resin (A3) was 55000.

[Example 1]

With respect to 50 parts by mass of the alkali-soluble resin (A1), BPE-500 (15 parts by mass), SR-494 (10 parts by mass), PBG-305 (0.5 parts by mass), Q-1301 (0.1 parts by mass), SBN- The photosensitive resin composition was adjusted by mixing 70D (10 parts by mass), FP-300 (15 parts by mass), and OIL BLUE 650 (0.15 parts by mass). The obtained photosensitive resin composition was obtained by the method described above to obtain a photosensitive film having a thickness of 15 μm. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[Example 2, Example 3 and Comparative Examples 1 to 3]

As an alkali-soluble resin and a photopolymerization initiator, a photosensitive film having a thickness of 15 µm was obtained in the same manner as in Example 1 except that the compound shown in Table 1 was used. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[Examples 4 to 6]

As a photopolymerization initiator, a photosensitive film having a thickness of 15 µm was obtained in the same manner as in Example 1, except that the compound shown in Table 1 was used. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[Example 7, Example 8, Comparative Example 4 and Comparative Example 5]

As a photopolymerization initiator and a polymerization inhibitor, a photosensitive film having a thickness of 15 µm was obtained in the same manner as in Example 1 except that the compound shown in Table 1 was used. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[Example 9 and Comparative Example 6]

As a polymerizable compound having a photopolymerization initiator and an unsaturated double bond, a photosensitive film having a thickness of 15 μm was obtained in the same manner as in Example 1 except that the compound shown in Table 1 was used. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[Example 10 and Comparative Example 7]

A photosensitive film having a thickness of 15 µm was obtained in the same manner as in Example 1, except that the compound shown in Table 1 was used, except for the block isocyanate compound. This photosensitive film was evaluated for light sensitivity, visibility of the exposed portion, development residue, blocking, wiring coverage, and stickiness by the above-described method. The composition of the photosensitive resin composition is shown in Table 1 below, and the evaluation results are shown in Table 2 below.

The symbol in Table 1 is as follows. In addition, in Table 1 below, the compounding amount is shown by mass solid content ratio.

(A) component: alkali-soluble resin

A1: Alkali-soluble resin (A1)

A2: Alkali-soluble resin (A2)

A3: Alkali-soluble resin (A3)

(B) component: a compound having an unsaturated double bond

B1: EO-modified bisphenol A dimethacrylate

B2: Ethoxylated pentaerythritol tetraacrylate

B3: Trimethylolpropane PO-modified triacrylate

(C) component: photopolymerization initiator

C1: 1,2-propanedione-3-cyclopentyl-1-[4-(phenylthio)phenyl]-2-(O benzoyloxime)

C2: 3-cyclopentylpropanone-1-(6-2-formylthiophen-9-ethylcarbazol-3-yl)-1-oxime acetate

C3: 3-cyclopentylpropanone-1-(6-formylfuran-9-ethylcarbazol-3-yl)-1-oxime acetate

C4: 3-cyclopentyl-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]propanone-1-(O-acetyloxime)

C5: Ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime)

(D) component: polymerization inhibitor

D1: N-nitrosophenylhydroxylamine aluminum

D2: N-nitrosophenyl hydroxylamine ammonium salt

D3: p-methoxyphenol

(E) Component: Block isocyanate

E1: Block isocyanate

(F) component: phosphorus compound

F1: phosphazene compound

(G) Ingredient: Other compounds

G1: Solvent Blue 70

The wiring protective films using the photosensitive films obtained in Examples 1 to 10 were of high quality with good wiring coverage and exhibiting excellent practical properties compared to the wiring protective films using the photosensitive films of Comparative Examples 1 to 7 . In addition, the wiring protective film using the photosensitive films obtained in Examples 1 to 10 had good visibility of the exposed portion and the unexposed portion, and it was easy to avoid double exposure at the production site. The photosensitive film using the nitroso compound of Example 1 and Example 7 and/or the compound consisting of a nitro compound was superior in photosensitivity to the photosensitive film of Example 8. (D)pentaerythritol (meth) as a compound having a small adhesiveness and an unsaturated double bond in the photosensitive film layer after development and/or firing, as compared with the photosensitive films of Examples 9 and 10 in Example 1. The acrylate ester compound and the block isocyanate compound are particularly preferable for improving process margins such as blocking and sticking property to metal jigs, and it was confirmed that they can contribute to improvement in suitability and productivity in a roll-to-roll production method.

On the other hand, the wiring protection film using the photosensitive films obtained in Comparative Examples 1 to 7 had poor visibility of the exposed portion and wiring coverage. This is considered to be because the photopolymerization initiator does not have a bulky substituent, so that sufficient crosslinking is not formed between the polymerizable compound having an unsaturated double bond and the photopolymerization initiator.

[Example 11]

<Production of photosensitive film roll>

The photosensitive resin composition described in Example 1 was coated using a comma coater (manufactured by Hiranotech Seed). The PET film (Teijin DuPont Film Co., G2, film thickness = 16 µm) was applied so that the film thickness after drying was 8 µm and 12 µm, respectively. Next, after drying the dryer zone at 95° C. for 6 minutes, a polyethylene film (manufactured by Tama Poly, GF-818, film thickness=19 μm) was bonded as a protective layer to obtain a photosensitive film roll. The film thickness was measured using a film thickness meter (ID-C112B, manufactured by Mitutoyo).

<Production of flexible printed wiring boards>

After half-etching the copper thickness of the flexible substrate roll (Espanex: MC12-20-00CEM, manufactured by Shinnitetsu Chemical) to 6 μm, the migration test wiring (conductor width) in accordance with JPCA-2006-DG2 Annex 2 on the copper surface /The conductor roll gap was 50/50 micrometers, the number of patterns was 10) and the test roll board|substrate which formed the beta copper foil part (5 cm x 5 cm) was prepared.

Next, a roll temperature of 80°C, a cylinder pressure of 0.4 MPa, a vacuum degree of 100 Pa, and a speed of 1 m/min were set using a roll-type thermal vacuum laminator (MVR-250), and the test roll was set. After laminating a photosensitive film (film thickness = 8 µm, 12 µm) on the copper wiring surface of the substrate, respectively, the migration test wiring (conductor width/conductor gap is 50/50 µm, the number of patterns is 10) and the beta copper foil portion (5 cm x 5 cm) was cut out to prepare a test sheet substrate.

Next, a photomask was placed to shield the electrode portion of the migration test wiring, and a step tablet (Stouffer21) was placed on the beta copper foil portion. Then, both were vacuum-contacted, and then exposed to 100 mJ/cm 2 with an ultra-high pressure mercury lamp (HMW-201KB, manufactured by Oku Corporation). Thereafter, the PET film was peeled from the obtained laminate, and spray development treatment and rinsing with water were performed at 30° C. for 1.0 mass% sodium carbonate solution for 60 seconds, followed by drying to prepare a photolithographic pattern of the photosensitive resin composition.

Next, by using a dryer (SPHH-10l, manufactured by ESPEC) at 180°C for 1 hour, a flexible printed wiring board having a coverlay film on a copper wiring surface was obtained.

<Practical characteristics evaluation>

The practical properties of the flexible printed wiring board produced by the above method were observed using a naked eye or a microscope, and the practical properties of the photosensitive film were evaluated according to the quality. About the following evaluation, ◎ or ○ was set as the pass. Table 3 shows the evaluation results.

(Evaluation of wiring coverage after exposure to 100 mJ/cm 2 and development for 60 seconds)

Migration test of photolithography pattern The state of the photosensitive film on the wiring was observed with an optical microscope (50 times). The evaluation criteria are as follows.

◎: No swelling or peeling of the photosensitive film on the wiring was observed.

(Circle): Although swelling of the photosensitive film on the edge part of a wiring is observed, copper wiring is not exposed because it does not peel off.

Δ: A part of the photosensitive film on the wiring is peeled off, and the copper wiring is exposed.

X: Most of the photosensitive film on the wiring is peeled off, so that the copper wiring is completely exposed.

(Sectional observation of flexible printed wiring board)

The flexible printed wiring board manufactured by the above method is embedded with an epoxy resin, and the embedded wiring board is polished perpendicularly to the wiring using a polishing apparatus (manufactured by Marumoto Stratus), and observed with an optical microscope having a measuring function. Then, the average value of the minimum thickness (a) of the coverlay film on the eight central copper wirings except for both ends of the copper wiring pattern and the value of the maximum value (b) of the surface step difference of the film obtained by firing the portion on the wiring and without the wiring Measured. Moreover, about the evaluation, ten places were observed and the average value of (a) and (b) was computed.

(Test of corrosion resistance)

The flexible printed wiring board manufactured by the above method was used as a sample, and a 180° bending to 180 degree test was performed to be perpendicular to the copper wiring. The bending was performed such that the coverlay film was inside, and the sample was placed on a 10 cm×10 cm glass plate, and held for 10 seconds at a weight of 750 g. Then, it observed with the optical microscope (50 times) from the coverlay film side. The evaluation criteria are as follows.

◎: No crack is generated in the coverlay film on the wiring.

(Circle): Although small and fine cracks were observed in the coverlay film on the wiring, there was no exposure of the copper wiring.

×: Small and fine cracks and/or large cracks are generated in the coverlay film on the wiring, and the copper wiring is exposed.

[Examples 12 to 20 and Comparative Examples 8 to 14]

Production of the photosensitive film roll, production of a flexible printed wiring board, and evaluation of practical properties were performed in the same manner as in Example 11 except that the photosensitive films described in Examples 2 to 10 and Comparative Examples 1 to 7 were used. Table 3 shows the evaluation results.

[Comparative Examples 15-17]

Production of the photosensitive film roll, production of a flexible printed wiring board, and evaluation of practical properties were carried out in the same manner as in Example 11 except that the photosensitive resin compositions described in Comparative Examples 1 to 3 were respectively applied so that the film thickness after drying was 25 µm. . The evaluation results are shown in Table 4 below.

The wiring protective film using the photosensitive film rolls obtained in Examples 11 to 20 was compared with the wiring protective film using the photosensitive films of Comparative Examples 8 to 14, even in regions where the thickness (a) on the wiring was small. The wiring coverage was good even under the low exposure amount and the overdevelopment condition than the lithography condition. In addition, the coverlay film using the photosensitive films obtained in Examples 11 to 20 has a film thickness region in which both the film thickness (a) and the surface smoothness (b) on the copper wiring show small values, resulting in bending It is thought that cracks do not occur on the surface of the coverlay film and copper wiring is not exposed because the stress of is uniformly distributed. As a result, it was confirmed that the photosensitive films described in Examples 11 to 20 had very excellent wiring coverage and high flexibility.

On the other hand, when the thickness (a) on a wiring is thin, the photosensitive films described in Comparative Examples 8 to 10 cannot satisfy wiring coverage. As in Comparative Examples 15 to 17, by increasing the thickness (a) on the wiring, the wiring coverage is improved, but the cut resistance cannot be satisfied. This is presumed to be caused by not having a film thickness region that satisfies the values (a) and (b) simultaneously.

From the above, it was confirmed that the photosensitive film of the present embodiment is a wiring protective film suitable for a flexible printed wiring board that contributes to improvement of suitability and productivity in a roll-to-roll production method.

The present invention has an effect of obtaining a photosensitive film that can obtain a wiring protection layer having excellent light sensitivity and high reliability. In particular, the surface protective film of the semiconductor element, the interlayer insulating film, the semiconductor package substrate, the protection for the flexible printed circuit board It can be preferably used for the field of an insulating film.

This application is based on the Japanese patent application 2012-175936 of the August 8, 2012 application. All of this is included here.

Claims (2)

A photosensitive resin comprising a circuit board having wiring, and on the circuit board, covering the wiring, comprising (A) an alkali-soluble resin, (B) a polymerizable compound having an unsaturated double bond, and (C) a photopolymerization initiator. A flexible printed wiring board comprising a film obtained by firing a coverlay film formed of a composition, wherein the minimum thickness (a) of the film obtained by firing on the wiring is 2 µm or more and 8 µm or less, and the portion on the wiring and without wiring The flexible printed wiring board, characterized in that the maximum value (b) of the surface step difference of the film obtained by firing is 3 µm or less. delete

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