JP2006208853A - Photosensitive resin composition and photosensitive element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition which can form a solder resist having fully high thermal shock resistance, and can also form a dry film exhibiting fully superior storage stability. <P>SOLUTION: The photosensitive resin composition contains (A) a resin, having a repeating unit represented by Formula (1) [where R<SP>1</SP>denotes a divalent organic group which is a diglycidyl ether type epoxy compound residue; R<SP>2</SP>denotes a divalent organic group which is a dibasic acid residue; and R<SP>3</SP>denotes H or a specific group] (B) a photopolymerizable compound, having an ethylenically unsaturated group within the molecule, (C) a photopolymerization initiator, (D) a diluent and (E) a compound that is slightly soluble in the diluent and having an epoxy group and/or a polyfunctional oxetane compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive resin composition and a photosensitive element.

  2. Description of the Related Art Conventionally, with the miniaturization and / or weight reduction of various electronic devices, a photosensitive solder resist is used for the purpose of forming a circuit pattern on a package substrate incorporating a printed wiring board and a semiconductor element. Such a solder resist photosensitive material has excellent photosensitive characteristics such as good developability and high resolution as well as good electrical insulation, high solvent resistance and high characteristics as characteristics for forming a fine pattern. Excellent properties as an insulating material such as alkali resistance are required. In addition to the Pb-free solder in recent years, in addition to the above characteristics, especially the solder resist used for the package substrate has excellent solder heat resistance, high thermal shock resistance, and high temperature and high humidity in a high temperature environment of about 260 ° C. There is also a demand for excellent moisture and heat resistance that can function stably as a solder resist even in the environment.

  Furthermore, a solder resist for a package substrate that requires a particularly fine opening pattern is required to have further resistance (thermal shock resistance) to a temperature cycle test (TCT) of, for example, −55 ° C. to 125 ° C. Such solder resists are also required to have physical properties as a member of a printed wiring board or a package substrate, such as high tensile strength, elongation rate, and electric corrosion resistance.

  As a method of forming a solder resist on a printed wiring board or the like, there is a method using a liquid photoresist. From the viewpoint of production efficiency and uniformity of resist film thickness, so-called dry resist as disclosed in Patent Document 1 is also available. A method using a film resist is becoming mainstream. As a dry film resist material that satisfies the above characteristics required for a solder resist, for example, Patent Document 2 discloses that a cured film having excellent heat resistance, heat and humidity resistance, adhesion, and mechanical properties can be obtained. A saturated or unsaturated esterified product of an epoxy compound (a) and an unsaturated monocarboxylic acid for the purpose of providing a photosensitive resin composition suitably used for the production of high-density multilayer boards and semiconductor packages At least one photosensitivity selected from a photosensitive resin (A) having a carboxyl group obtained by reacting a polybasic acid anhydride, a photosensitive polyamide resin having a carboxyl group, and a photosensitive polyamideimide resin having a carboxyl group A photosensitive resin composition containing a resin (B), an elastomer (C), an epoxy curing agent (D), and a photopolymerization initiator (E) is proposed. It is. According to Patent Document 2, it is described that a solder resist formed from this photosensitive resin composition is excellent in solvent resistance.

  Further, in Patent Document 3, for example, a solder resist film or the like excellent in printability, heat resistance, adhesion to the application surface, chemical resistance, solvent resistance, electrical properties, and mechanical properties on the application surface is formed. A mixture of a novolak epoxy resin having a specific structure and a rubber-modified bisphenol A type epoxy resin having a specific structure, and an epoxy equivalent of 0.2 Reaction product of -1.2 mol of ethylenically unsaturated carboxylic acid with 0.2-1.0 mol of polybasic acid and / or its anhydride per epoxy equivalent of the above mixture. A photosensitive resin composition containing a photosensitive prepolymer having a carboxyl group, (B) a photopolymerizable reactive diluent, (C) a photopolymerization initiator, and (D) a thermosetting component has been proposed.

Furthermore, Patent Document 4 discloses a permanent mask resist that exhibits high moisture resistance insulation without lowering flexibility, solder heat resistance, and chemical resistance as a permanent mask resist. In the rinsing step, means for incorporating divalent inorganic ions such as divalent calcium ions into water for rinsing is disclosed.
Japanese Patent Laid-Open No. 54-1018 Japanese Patent Laid-Open No. 11-288087 Japanese Patent Laid-Open No. 9-5997 JP 2004-252485 A

  However, the present inventors have examined the conventional photosensitive resin composition described in Patent Documents 2 and 3 in detail, and the solder resist obtained from such a conventional photosensitive resin composition is: Furthermore, it has been found that it cannot sufficiently meet the demand for excellent thermal shock resistance. Further, the present inventors have found that when a dry film is formed from such a conventional photosensitive resin composition, sufficient storage stability cannot be obtained.

  Furthermore, the present inventors have found that when the means disclosed in the above-mentioned Patent Document 4 is used, although there is a certain effect with respect to electric corrosion resistance, the thermal shock resistance is still insufficient.

  Therefore, the present invention has been made in view of the above circumstances, a photosensitive resin composition capable of forming a solder resist having sufficiently high thermal shock resistance and capable of forming a dry film exhibiting sufficiently excellent storage stability. The purpose is to provide goods. Another object of the present invention is to provide a photosensitive element obtained from the photosensitive resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have incorporated a resin having a specific structure into the photosensitive resin composition and are not necessarily included in the ordinary photosensitive resin composition. The inventors have found that the above object can be achieved by including a compound exhibiting specific properties, and have completed the present invention.

で表される繰り返し単位を有する変性エポキシ樹脂と、（Ｂ）分子内にエチレン性不飽和基を有する光重合性化合物と、（Ｃ）光重合開始剤と、（Ｄ）希釈剤と、（Ｅ）希釈剤に難溶であるエポキシ基を有する化合物、及び／又は、多官能のオキセタン化合物とを含有する感光性樹脂組成物を提供する。 The present invention provides (A) the following general formula (1);

A modified epoxy resin having a repeating unit represented by: (B) a photopolymerizable compound having an ethylenically unsaturated group in the molecule, (C) a photopolymerization initiator, (D) a diluent, (E ) A photosensitive resin composition containing a compound having an epoxy group that is hardly soluble in a diluent and / or a polyfunctional oxetane compound.

で表される基を示す。また、式（２）中、Ｒ^４は酸無水物残基を示す。 Here, in Formula (1), R ¹ represents a divalent organic group that is a diglycidyl ether type epoxy compound residue, R ² represents a divalent organic group that is a dibasic acid residue, and R ³ Is a hydrogen atom or the following general formula (2);

The group represented by these is shown. In formula (2), R ⁴ represents an acid anhydride residue.

で表される化合物のことをいう。ここで、Ｒ^１は二価の有機基を示す。 Further, the “diglycidyl ether type epoxy compound” means the following general formula (4):

The compound represented by these. Here, R ¹ represents a divalent organic group.

で表される樹脂と、（Ｂ）分子内にエチレン性不飽和基を有する光重合性化合物と、（Ｃ）光重合開始剤と、（Ｄ）希釈剤と、（Ｅ）希釈剤に難溶であるエポキシ基を有する化合物、及び／又は、多官能のオキセタン化合物を含有する感光性樹脂組成物を提供する。 The present invention relates to (A) the following general formula (3);

(B) a photopolymerizable compound having an ethylenically unsaturated group in the molecule, (C) a photopolymerization initiator, (D) a diluent, and (E) a poorly soluble in diluent. A photosensitive resin composition containing a compound having an epoxy group and / or a polyfunctional oxetane compound is provided.

で表される基を示し、ｎは１以上の整数を示す。また、式（２）中、Ｒ^４は酸無水物残基を示す。 Here, in Formula (3), R ¹ represents a divalent organic group that is a diglycidyl ether type epoxy compound residue, R ² represents a divalent organic group that is a dibasic acid residue, and R ³ Is a hydrogen atom or the following general formula (2);

And n represents an integer of 1 or more. In formula (2), R ⁴ represents an acid anhydride residue.

  The photosensitive resin composition of the present invention is a dry film that exhibits sufficiently excellent storage stability by simultaneously containing the components (A), (B), (C), (D), and (E) described above. And a solder resist exhibiting sufficiently high thermal shock resistance can be formed. The reason for this is not clarified in detail at present, but the present inventors consider a part thereof as follows. However, the factors are not limited to these.

  In the conventional photosensitive resin compositions disclosed in Patent Documents 1 and 2, the glycidyl group in the epoxy curing agent (D) and the carboxyl group in the photosensitive resin (A) or (B) react at room temperature. End up. Therefore, when this is used as a liquid resist material, a two-part resist material in which the photosensitive resins (A) and (B) and the epoxy curing agent (D) are divided into a main agent and a curing agent, respectively. This prevents the above reaction. However, when this photosensitive resin composition is used as a material for a dry film resist, it is obtained because the photosensitive resins (A) and (B) and the epoxy curing agent (D) are blended in the same film. The above-described reaction proceeds in the dry film, and it becomes difficult to show sufficient storage stability.

  On the other hand, the photosensitive resin composition of the present invention employs a compound having an epoxy group that is hardly soluble in a diluent or a polyfunctional oxetane compound as the one corresponding to the epoxy curing agent (D) of Reference Document 1. ing. The compound having an epoxy group that is hardly soluble in the diluent is sufficiently inhibited from reacting with the polyester resin as the component (A) of the present invention due to the poor solubility in the diluent. Moreover, the reactivity of the polyfunctional oxetane compound is sufficiently suppressed as compared with the epoxy curing agent. As a result, when using the photosensitive resin composition of the present invention containing these compounds and the resin of the component (A) as one liquid, or forming a dry film from the photosensitive resin composition of the present invention, It is presumed that sufficiently excellent storage stability can be exhibited. Therefore, the photosensitive resin composition of the present invention has sufficiently good properties such as coating properties, cured film resolution and thermal shock resistance even after being stored for a long time in a one-component state or in a dry film state. Can be maintained.

  Moreover, when the photosensitive resin composition of the present invention is irradiated with light, the photopolymerizable compound as the component (B) is polymerized. Furthermore, by heating the photosensitive resin composition, the compound having an epoxy group that is hardly soluble in the diluent of the component (E) gradually dissolves in the diluent. Or the reactivity of the polyfunctional oxetane compound of (E) component becomes high gradually by further heating the photosensitive resin composition. A compound having an epoxy group dissolved in a diluent or a polyfunctional oxetane compound having increased reactivity forms a three-dimensional crosslink in the photosensitive resin composition. As a result, the present inventors speculate that the photosensitive resin composition of the present invention forms a cured product, and as a result, a solder resist exhibiting sufficiently high thermal shock resistance can be formed.

In order to obtain a photosensitive solder resist, a process of forming a coating film of a photosensitive material on an insulating substrate or the like is performed. From the viewpoint of ensuring good production efficiency, the surface of the coating film is not sticky. It is also required to be suppressed, that is, to have excellent coating properties. When the photosensitive resin composition of the present invention is applied on a substrate, the coating film is sufficiently suppressed in stickiness and is very excellent in workability.
Furthermore, a photosensitive resin composition using blocked isocyanate as a thermosetting component and a polyamide type photosensitive resin composition having excellent heat resistance can be used for the elimination of the blocking agent or the condensation reaction of polyamic acid during thermosetting. Accordingly, outgas is generated, and the degree of curing shrinkage tends to increase with the generation of the outgas. Since the photosensitive resin composition of the present invention can be sufficiently heat-cured without containing such components, it is possible to suppress the above-mentioned outgas generation and curing shrinkage, and the coating thickness uniformity. And it leads to the further improvement of flatness.

  The photosensitive resin composition of the present invention contains the above-mentioned components (A), (B), (C), (D) and (E) at the same time, so that the good developability required for the photosensitive material. In addition, it has high resolution and can satisfy characteristics and reliability required for a solder resist, an interlayer insulating film, a semiconductor protective film, and the like provided in a printed wiring board including a flexible wiring board and a package substrate. In addition, the solder resist obtained from the photosensitive resin composition of the present invention is sufficiently excellent in thermal shock resistance, and due to the same factors, it has alkali resistance, solder heat resistance, and electrolytic Ni / Au plating resistance. In addition, it has excellent mechanical properties such as elongation and tensile strength, and electric corrosion resistance.

  In the photosensitive resin composition of the present invention, the resin of component (A) is a first step in which an intermediate product is obtained by a polymerization reaction between a diglycidyl ether type epoxy compound and a dibasic acid, and the intermediate product is subjected to acid anhydride. It may be obtained by a method for producing a resin having a second step of adding a product. Such a resin has an ester-type chain bond, and since the whole molecule tends to have a chain structure, it is considered that gelation tends to be difficult. Therefore, in a photosensitive element including a photosensitive layer formed of a photosensitive resin composition containing such a resin, when a resist film is formed using the photosensitive element, development using a dilute alkaline aqueous solution is performed more satisfactorily. be able to.

  In the first step, the viewpoint of further increasing the molecular weight of the polyester resin, the viewpoint of further improving the developability with a dilute alkaline aqueous solution, the viewpoint of obtaining further excellent storage stability, the viewpoint of obtaining better coating properties, etc. Therefore, the diglycidyl ether type epoxy compound and the dibasic acid are blended so that the equivalent ratio of the active hydrogen possessed by the dibasic acid to the epoxy group possessed by the diglycidyl ether type epoxy compound is 1.03 to 1.30. And preferred.

  The dibasic acid is preferably a dicarboxylic acid from the viewpoint of improving both the thermal shock resistance and the developability.

  The present invention provides a photosensitive element comprising a support and a photosensitive layer made of the above-described photosensitive resin composition formed on the support. The photosensitive layer in this photosensitive element is a so-called dry film, and, as is clear from the above, not only has excellent thermal shock resistance, but also physical properties such as resolution, solder heat resistance, developability, and the above-mentioned mechanical properties. In addition, it tends to be excellent in all of the electric corrosion resistance, and enables efficient production of high-resolution and high-density printed wiring boards.

  According to the present invention, it is possible to provide a photosensitive resin composition capable of forming a solder resist having sufficiently high thermal shock resistance and capable of forming a dry film exhibiting sufficiently excellent storage stability.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In the present specification, “(meth) acrylic acid” means “acrylic acid” and “methacrylic acid” corresponding thereto, and “(meth) acrylate” means “acrylate” and “methacrylate” corresponding thereto. “(Meth) acryloxy group” means “acryloxy group” and its corresponding “methacryloxy group”, and “(meth) acryloyl group” means “acryloyl group” and its corresponding “methacryloyl group”. means.

  The photosensitive resin composition of the present invention comprises (A) a resin having a repeating unit represented by the general formula (1), (B) a photopolymerizable compound having an ethylenically unsaturated group in the molecule, ( C) A photopolymerization initiator, (D) a diluent, (E) a compound having an epoxy group that is hardly soluble in the diluent, and / or a polyfunctional oxetane compound. Hereinafter, preferred embodiments of the photosensitive resin composition of the present invention will be described.

<(A) component>
Examples of the resin having a repeating unit represented by the general formula (1) as the component (A) include those represented by the general formula (3). As is clear from the general formulas (1) and (3), the resin of the component (A) is a polyester resin having an ester bond (—COO—) in the main chain.

  The weight average molecular weight (Mw) of the polyester resin can be measured by gel permeation chromatography (GPC) (in terms of standard polystyrene). The conditions for GPC are as follows.

[GPC conditions]
Pump: Hitachi L-6000 type [manufactured by Hitachi, Ltd.]
Detector: Hitachi L-4000 UV [manufactured by Hitachi, Ltd.]
Column: Gelpack GL-S300MDT-5 (two in total) (trade name, manufactured by Hitachi Chemical Co., Ltd.)
Column size: 8mmφ × 300mm
Eluent: DMF / THF = 1/1 + 0.06M phosphoric acid + 0.06M lithium bromide
Sample concentration: 5 mg / 1 mL
Injection volume: 5 μL
Pressure: 343 Pa (35 kgf / cm ² )
Flow rate: 1.0 mL / min

  According to this measurement method, the Mw of the polyester resin is 10,000 to 10,000 from the viewpoint of coating properties (difficulty in stickiness), developability with a dilute aqueous alkali solution, and mechanical properties such as tensile strength and elongation. It is preferably 80000, more preferably 15000 to 70000, even more preferably 20000 to 60000, and particularly preferably 25000 to 50000.

  The photosensitive resin composition of this embodiment can be sufficiently dissolved in a dilute alkali developer even if it contains a relatively high molecular weight polyester resin. In particular, as the component (A) contains more linear polyester resin as represented by the general formula (3), the solubility tends to be improved. Moreover, when (A) component contains many linear polyester resins, it exists in the tendency which can improve various characteristics, such as the solubility with respect to the solvent of the photosensitive resin composition.

In the structural formula of the polyester resin represented by the general formula (3) described above, the upper limit value of n varies depending on the types of residues of R ¹ , R ² , R ^3, and R ⁴ , but this weight It is preferable to set the value of n such that the average molecular weight is 70,000 as the upper limit.

The acid value of the polyester resin can be measured by the following method. First, about 1 g of a polyester resin solution is precisely weighed, 30 g of acetone is added to the resin solution, and the resin solution is uniformly dissolved. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous KOH solution. And from the titration result, the following formula (5);
A = 10 × Vf × 56.1 / (Wp × I) (5)
Is used to calculate the acid value. In the formula, A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of phenolphthalein, Wp represents the mass (g) of the polyester resin solution, and I represents the nonvolatile content in the polyester resin solution. The ratio (mass%) of minutes is shown.

  According to this measurement method, the acid value of the polyester resin is 50 to 200 mgKOH / percent from the viewpoint of developability with a dilute alkaline aqueous solution and the electrical insulation, chemical resistance and plating resistance of the resulting cured film. It is preferable that it is g, and it is still more preferable that it is 90-150 mgKOH / g.

  Such a polyester resin can be synthesized by the following method.

  The polyester resin synthesis method includes a first step of obtaining an intermediate product by polymerization reaction of a diglycidyl ether type epoxy compound having two glycidyl groups in one molecule and a dibasic acid, and an acid anhydride is added to the intermediate product. And a second step of obtaining a polyester resin as described above by adding a product.

(First step)
The diglycidyl ether type epoxy compound used as a raw material in the first step is not particularly limited, but preferably further has one or more phenoxy groups in one molecule, and further has two or more phenoxy groups in one molecule. It is more preferable.

  Examples of the epoxy compound include bisphenol A type epoxy resins such as bisphenol A diglycidyl ether, bisphenol F type epoxy resins such as bisphenol F diglycidyl ether, bisphenol S type epoxy resins such as bisphenol S diglycidyl ether, and biphenol diglycidyl. Biphenol type epoxy resins such as ether, bixylenol type epoxy resins such as bixylenol diglycidyl ether, hydrogenated bisphenol A type epoxy resins such as hydrogenated bisphenol A glycidyl ether, and dibasic acid-modified diglycidyl ether type epoxies thereof Resin etc. are mentioned. Among these, bisphenol A type epoxy resins are preferred because they are excellent in heat resistance and chemical resistance and do not relatively shrink due to curing. These may be used alone or in combination of two or more.

Incidentally, diglycidyl ether type epoxy compound residues represented by R ¹ in general formula (1), the structure of these epoxy compounds, the portion excluding the glycidyl group.

Commercially available compounds can be used as these epoxy compounds. Examples of bisphenol A diglycidyl ether include Epicoat 828, Epicoat 1001 and Epicoat 1002 (above, trade name, manufactured by Japan Epoxy Resin Co., Ltd.). Examples of bisphenol F diglycidyl ether include Epicoat 807 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.), and examples of bisphenol S diglycidyl ether include EBPS-200 (product name, manufactured by Nippon Kayaku Co., Ltd.) and Epicron EXA- 1514 (trade name, manufactured by Dainippon Ink & Chemicals, Inc.). Examples of biphenol diglycidyl ether include YL-6121 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.), and examples of bixylenol diglycidyl ether include YX-4000 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.). Can be mentioned. Furthermore, examples of the hydrogenated bisphenol A glycidyl ether include ST-2004 and ST-2007 (manufactured by Tohto Kasei Co., Ltd., trade name). -5100 and ST-5080 (above, manufactured by Tohto Kasei Co., Ltd., trade name). The above-mentioned diglycidyl ether type epoxy compounds can be used singly or in combination of two or more.

  The epoxy equivalent of these diglycidyl ether type epoxy compounds (gram weight of the compound containing 1 equivalent of an epoxy group) can be measured according to JIS K 7236 “How to determine the epoxy equivalent of an epoxy resin”. According to this measurement method, the epoxy equivalent of the epoxy compound is preferably 160 to 3300, and more preferably 180 to 980, from the viewpoint of developability with a dilute aqueous alkali solution.

  The dibasic acid used as a raw material in the first step is preferably a dicarboxylic acid from the viewpoint of improving both thermal shock resistance and developability. Specifically, for example, maleic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid and methylendomethylenetetrahydrophthalic acid Can be mentioned. These can be used alone or in combination of two or more. Of these dibasic acids, tetrahydrophthalic acid is more preferred. Hereinafter, the case where dicarboxylic acid is used as a dibasic acid will be described.

In addition, the dibasic acid residue represented by R ² in the general formula (1) described above is a portion excluding the dibasic acid functional group (carboxyl group in the case of dicarboxylic acid) in the structure of these compounds. Become.

  The polymerization reaction in the first step can be performed by a conventional method. The compounding ratio of the diglycidyl ether type epoxy compound and the dibasic acid dicarboxylic acid is from the viewpoint of the molecular weight of the polyester resin, from the viewpoint of developability with a dilute alkaline aqueous solution, from the viewpoint of storage stability, and from the viewpoint of coating properties, etc. The compounding ratio is preferably such that the equivalent ratio of the active hydrogen possessed by the dicarboxylic acid to the epoxy group possessed by the diglycidyl ether type epoxy compound is 1.03 to 1.30 and 1.03 to 1.30. The active hydrogen is equivalent to the carboxyl group. By adjusting the blending ratio of the diglycidyl ether type epoxy compound and the dibasic acid in this manner, the carboxyl group becomes excessive with respect to the epoxy group, and thus the resulting polyester resin tends to have a carboxyl group at the terminal.

  Examples of the catalyst used for the polymerization reaction in the first step include phosphines, alkali metal compounds, and amines. Specifically, for example, phosphines such as tributylphosphine and triphenylphosphine, alkali metal compounds such as sodium hydroxide, lithium hydroxide, and potassium hydroxide, triethanolamine, N, N′-dimethylpiperazine, triethylamine, triethylamine, Examples include amines such as -n-propylamine, hexamethylenetetramine, pyridine, and tetramethylammonium bromide. These can be used singly or in combination of two or more.

  Among these, as the catalyst used in the polymerization reaction in the first step, a tertiary amine having a pKa of 9.0 or less is preferable, and a tertiary amine having a pKa of 7.3 or less is more preferable. By using such a catalyst, the polyester resin represented by the general formula (1) and further the general formula (3) described above can be synthesized more selectively, and the molecular weight of the polyester resin can be increased. It tends to be bigger. Among the specific catalysts described above, those other than phosphines and alkali metal compounds are used from the viewpoint of preventing gelation due to the bond type (ether type network bond and / or ester type network bond) in the obtained polyester resin. Or a tertiary amine having a pKa of 9.0 or less.

  The intermediate product generated by the polymerization reaction in the first step described above is a chain structure by an ester bond generated by the reaction between a carboxyl group and a glycidyl group, and an ether generated by a reaction between a hydroxyl group and a glycidyl group. A network structure formed by a bond and a network structure formed by an ester bond formed by a reaction between a hydroxyl group and a carboxyl group can be formed. When the obtained intermediate product has many network structures based on ether bonds and network structures based on ester bonds among these structures, it is considered that the intermediate product tends to form a three-dimensional structure as a whole. Therefore, since the intermediate product and the polyester resin obtained after the second step described later tend to gel, a dilute alkaline aqueous solution or the like is used for the uncured portion of the resist film formed by using such a resin. It tends to be not removed even by development.

  On the other hand, the intermediate product synthesized by using the above-described catalyst is further subjected to a second step using this, thereby starting from the one represented by the general formula (1), due to an ester bond in the molecule. Since a polyester resin having a lot of chain bonds and a chain structure as a whole can be obtained, it is considered that gelation tends to be difficult. Therefore, the uncured portion of the solder resist formed by using such a polyester resin is easily removed by development using a dilute alkaline aqueous solution or the like.

  The amount of the catalyst used is a total amount of diglycidyl ether type epoxy compound and dibasic acid from the viewpoint of polymerization reaction rate and from the viewpoints of heat resistance and electric corrosion resistance of the cured film obtained from the photosensitive resin composition. It is preferable in it being 1-10 mass parts with respect to a mass part.

  The reaction temperature in the first step is preferably 100 to 150 ° C. from the viewpoint of the polymerization reaction rate and the prevention of the side reaction.

(Second step)
In the second step, a polyester resin is synthesized by reacting the intermediate product generated in the first step with an acid anhydride.

  Examples of the acid anhydride used in the second step include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, Dibasic acid anhydrides such as methylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, etc. Aromatic polycarboxylic anhydrides and other polyvalent carboxylic acids such as 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride associated therewith And acid anhydride derivatives.

  Of these, dibasic acid anhydrides are preferably used, and dicarboxylic acid anhydrides are more preferably used. Moreover, these can be used individually by 1 type or in combination of 2 or more types.

In addition, the acid anhydride residue represented by R ⁴ in the general formula (1) described above is a portion excluding the acid anhydride functional group in the structure of these compounds.

  The amount of acid anhydride added is the functional group equivalent ratio (in the acid anhydride to be added) from the viewpoint of developability with dilute alkaline aqueous solution and the heat resistance and electric corrosion resistance of the finally obtained cured film. The acid anhydride group / the hydroxyl group of the intermediate product produced in the first step, the molar ratio) is preferably 0.6 to 1.3.

  The reaction temperature in the second step is preferably 80 to 130 ° C. from the viewpoint of reaction rate and the prevention of side reactions.

  In addition, in this polyester resin synthesis method, an appropriate amount of solvent is usually used. Specifically, for example, ketone compounds such as methyl isobutyl ketone, cyclohexanone or methylcyclohexanone, aromatic hydrocarbon compounds such as toluene, xylene or tetramethylbenzene, cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methylcarbitol, butyl Carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, glycol ether compounds such as dipropylene glycol diethyl ether or triethylene glycol monoethyl ether, ester compounds such as acetate compounds of the above glycol ether compounds, ethylene glycol or propylene glycol Alcohol compounds such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha It can be mentioned petroleum-based solvents such as solvent naphtha. These can be used individually by 1 type or in combination of 2 or more types.

<(B) component>
As the photopolymerizable compound having an ethylenically unsaturated group in the molecule as the component (B), for example, a bisphenol A (meth) acrylate compound; a polyhydric alcohol is reacted with an α, β-unsaturated carboxylic acid. Compound obtained; Compound obtained by reacting α, β-unsaturated carboxylic acid with glycidyl group-containing compound; Urethane monomer or urethane oligomer such as (meth) acrylate compound having urethane bond in molecule, and the like Nonylphenoxy polyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o- Phthalic acid compounds such as phthalates; (meth) acrylic acid alkyl esters, O-modified nonylphenyl (meth) acrylate or the like can be exemplified. These may be used alone or in combination of two or more.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned. These can be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexa) Decaethoxy) phenyl) propane and the like. These can be used alone or in combination of two or more.

  Of these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.). -Bis (4- (methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These can be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic) Xinonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxydodecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl) propane, 2,2-bis ( 4-((meth) acryloxytetradecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl) propane, 2,2-bis (4-((meth)) And acryloxyhexadecapropoxy) phenyl) propane. These may be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These can be used alone or in combination of two or more.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups. Polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) A Examples thereof include acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. Further, “EO modified” means having a block structure of ethylene oxide units (—CH ₂ —CH ₂ —O—), and “PO modified” means propylene oxide units (—CH ₂ —CH (CH ₃ )). -O-) having a block structure.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate, 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl and the like are fisted. These can be used alone or in combination of two or more.

  Examples of the α, β-unsaturated carboxylic acid include (meth) acrylic acid. These can be used alone or in combination of two or more.

  Examples of urethane monomers include (meth) acrylic monomers having an OH group at the β-position and diisocyanate compounds such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Additional reaction products, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, EO or PO-modified urethane di (meth) acrylate, and the like can be mentioned. These can be used alone or in combination of two or more.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, and the like. It is done. These can be used alone or in combination of two or more.

  These (B) components are used individually by 1 type or in combination of 2 or more types.

<(C) component>
Examples of the photopolymerization initiator (C) include benzophenone; N, N′-tetraalkyl-4,4′-diaminobenzophenone; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl). Aromatic ketones such as butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; quinones such as alkylanthraquinones; benzoin ether compounds such as benzoin alkyl ethers; benzoin Benzoin compounds such as alkylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2,4,5-triarylimidazole dimer; 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane, etc. Acridine derivatives; N-phenylglycine, N-phenylglycine derivatives Coumarin compounds and the like. These can be used singly or in combination of two or more.

<(D) component>
The diluent is not particularly limited as long as it can dilute the polyfunctional oxetane compound of components (A) to (C) and (E). Examples of the diluent include aliphatic alcohols, cyclic hydrocarbons, ketones, keto alcohols, alkylene glycols, alkylene glycol alkyl ethers, acetate compounds thereof, and carboxylic acid esters. These can be used alone or in combination of two or more.

  Examples of the aliphatic alcohol include methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pentanol, and n-hexanol. Examples of the cyclic hydrocarbon include benzyl alcohol, cyclohexane, and toluene. These can be used alone or in combination of two or more.

  Examples of the ketone include acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, methyl pentyl ketone, methyl hexyl ketone, ethyl butyl ketone, dibutyl ketone, cyclopentanone and cyclohexanone. Examples of keto alcohols include diacetone alcohol, 3-hydroxy-2-butanone, 4-hydroxy-2-pentanone, and 6-hydroxy-2-hexanone. These can be used alone or in combination of two or more.

  Examples of the alkylene glycol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and propylene glycol. Examples of the alkylene glycol alkyl ether include diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, triethylene glycol alkyl ether, propylene glycol alkyl ether and dipropylene glycol alkyl ether. More specifically, for example, 3-methoxy- Examples include 1-butanol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, methyl cellosolve, ethyl cellosolve, and butyl cellosolve. The acetate compound of alkylene glycol or alkylene glycol alkyl ether may be any of the above-mentioned alkylene glycol or alkylene glycol alkyl ether acetate compounds, such as ethylene glycol monoacetate, ethylene glycol diacetate, propylene glycol monoacetate, propylene glycol diacetate. Examples include acetate, methyl cellosolve acetate, and ethyl cellosolve acetate. These can be used alone or in combination of two or more.

  Examples of the carboxylic acid ester include ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate and ethyl butyrate. These can be used alone or in combination of two or more.

As the diluent as component (D), in addition to those described above, for example, γ-butyrolactone, phenyl cellosolve, dimethylformamide, dimethyl sulfoxide, dioxane, tetrahydrofuran, methyl lactate, ethyl lactate, methyl benzoate, ethyl benzoate and carbonic acid And propylene.
Among these diluents of component (D), those having a boiling point that volatilizes at the temperature at which the photosensitive resin composition is thermally cured are preferable.

  A diluent can be used individually by 1 type in the above-mentioned thing or in combination of 2 or more types.

<(E) component>
The component (E) is a compound having an epoxy group that is hardly soluble in the diluent and / or a polyfunctional oxetane compound.

  The compound having an epoxy group that is hardly soluble in the diluent is an epoxy group-containing compound, for example, having a solubility in a diluent at 20 ° C. of 40 g or less (40 g or less / 100 g methyl ethyl ketone) per 100 g of methyl ethyl ketone. . In this embodiment, if this solubility condition is satisfied, it can be said to be “slightly soluble in a diluent”, but in order to achieve the object effect of the present invention more effectively, the compound having an epoxy group at 20 ° C. The solubility in a diluent is preferably 35 g or less per 100 g of methyl ethyl ketone, and more preferably 30 g or less.

  As such a compound, in order to exhibit the effect of the present invention more effectively, for example, a compound having two or more glycidyl groups in one molecule and hardly soluble in a diluent is preferable. Examples of such a compound include triglycidyl isocyanate (a compound having three glycidyl groups and an isocyanate group in one molecule; commercially available products such as TEPIC (manufactured by Nissan Chemical Industries, Ltd., trade name), bixylenol type epoxy. Resin (commercially available products are YX4000, YL6056 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.)) and tetraglycidyl kiei lenoylethane resin (commercially available products are 2Y-1063 (manufactured by Toto Kasei Co., Ltd., trade name)) These may be used alone or in combination of two or more.

で表される２価の基を分子内に２個以上有するものが挙げられる。市販されているものとしては、例えば、アロンオキセタンＯＸＴ−１２１、ＯＸＴ−２２１（以上、東亜合成社製、商品名）などが挙げられる。 The polyfunctional, that is, bifunctional or higher oxetane compound is not particularly limited as long as it is a compound having two or more oxetane rings in one molecule. Examples of such oxetane compounds include the following formula (6);

And those having two or more divalent groups represented by As what is marketed, Aron oxetane OXT-121, OXT-221 (above, the Toa Gosei company make, brand name) etc. are mentioned, for example.

  In addition, when using the said oxetane compound as (E) component, in order to further activate the hardening reaction, you may use together curing catalysts, such as a triphenylphosphine.

  Any one of these compounds having an epoxy group and a polyfunctional oxetane compound which are hardly soluble in these diluents may be used alone, or both of them may be used in combination. Moreover, about each compound, 1 type may be used independently and 2 or more types may be used in combination.

  The content ratio of the component (A) in the photosensitive resin composition is the viewpoint of preventing exudation from the end face of the photosensitive element including the photosensitive layer made of the photosensitive resin composition, and more excellent solder heat resistance. And from a viewpoint of obtaining photosensitivity, it is preferably 30 to 70 parts by mass, and more preferably 45 to 55 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B).

  The content ratio of the component (B) is preferably 10 to 70 parts by mass and more preferably 35 to 55 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). . If this content is less than 10 parts by mass, the photosensitivity tends to be insufficient, and if it exceeds 70 parts by mass, the resulting cured product tends to be brittle.

  (C) The content rate of a component is 0.1-20 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component from a viewpoint of obtaining the more outstanding photosensitivity and solder heat resistance. It is preferable that it is 0.2 to 10 parts by mass.

  When the photosensitive resin composition is used in a liquid state, the content ratio of the component (D) is preferably 5 to 40% by mass with respect to the total amount of the photosensitive resin composition. In addition, when the photosensitive resin composition is applied to a support and used as a photosensitive layer of a photosensitive element, in the varnish state before coating, the content ratio of the component (D) is 30 with respect to the total amount of the varnish. It is preferable that it is -70 mass%. In this case, since a drying (volatilization) process is performed on the photosensitive layer when the photosensitive element is subsequently formed, usually 3% by mass or less based on the total amount of the photosensitive resin composition in the photosensitive layer. It becomes. Thereby, when using the compound which has an epoxy group hardly soluble in a diluent as (E) component, the (E) component can be more favorably dispersed in the state of fine solid particles in the photosensitive resin composition. In addition, since the reactivity with the carboxyl group of the component (A) tends to be further suppressed, further excellent storage stability of the photosensitive element can be obtained.

  The content ratio of the component (E) is the total amount of the component (A) and the component (B) from the viewpoint of improving the photosensitivity such as photosensitivity and resolution, and from the viewpoint of further improving the thermal shock resistance, electric corrosion resistance, and storage stability. It is preferable that it is 5-40 mass parts with respect to 100 mass parts, and it is more preferable that it is 10-30 mass parts.

  In addition, the photosensitive resin composition of the present embodiment, if necessary, is a photochromic component such as a thermosetting component such as a melamine resin or isocyanate block, a dye such as malachite green, tribromophenylsulfone or leucocrystal violet. Agent, thermo-color developing inhibitor or plasticizer such as p-toluenesulfonamide, phthalocyanine-based such as phthalocyanine green or phthalocyanine blue, azo-based organic pigments or inorganic pigments such as titanium dioxide, silica, alumina, talc, calcium carbonate or Fillers made of inorganic pigments such as barium sulfate, antifoaming agents, flame retardants, stabilizers, adhesion-imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances or imaging agents, and the like (A) and (B ) 0.01 to 20 parts per 100 parts by mass in total with the components It can contain about quantity unit. These can be used alone or in combination of two or more. Moreover, you may use together polymer components other than (A) component, such as an acryl-type copolymer and an acid-modified vinyl group containing epoxy resin.

  The photosensitive resin composition of the present embodiment can form a solder resist having sufficiently high thermal shock resistance, and can form a dry film exhibiting sufficiently excellent storage stability. Furthermore, it has excellent photosensitive properties such as good developability and high resolution, and can form a good coating film with reduced stickiness.

  In addition, the photosensitive resin composition of the present embodiment has characteristics required for a solder resist, an interlayer insulating film, a semiconductor protective film, and the like provided in a printed wiring board such as a rigid wiring board and a flexible wiring board and a package substrate. Reliability can be satisfied. The solder resist obtained from the photosensitive resin composition of the present embodiment is sufficiently excellent in thermal shock resistance, and in addition to alkali resistance, solder heat resistance, and electrolytic Ni / Au plating due to the same factors. It has excellent mechanical properties such as properties, elongation and tensile strength, and electric corrosion resistance.

  The photosensitive element of this invention is equipped with a support body and the photosensitive layer which consists of the photosensitive resin composition of this invention formed on this support body. Hereinafter, a preferred embodiment of the photosensitive element of the present invention will be described with reference to FIG. A photosensitive element 1 shown in FIG. 1 includes a support 11, a photosensitive layer 12 containing the photosensitive resin composition formed on the support, and a protective film 13 laminated on the photosensitive layer 12. It is to be prepared.

  The photosensitive layer 12 may be formed by dissolving the above-described photosensitive resin composition in the above solvent or mixed solvent to obtain a solution having a solid content of about 30 to 70% by mass, and then coating the solution on a support. preferable. Although the thickness of a photosensitive layer changes with uses, it is the thickness after drying which removed the solvent by heating and / or hot air blowing, and it is preferable that it is 10-100 micrometers, and it is more preferable that it is 20-60 micrometers. If the thickness is less than 10 μm, there is a tendency that it is difficult to apply (apply) industrially. If the thickness exceeds 100 μm, the above-described effect produced by the present invention tends to be small, and in particular, physical properties such as mechanical properties and resolution are low. It tends to decrease.

  Examples of the protective film 13 include polyethylene film, polypropylene film, Teflon (registered trademark) film, and surface-treated paper. The protective film 13 preferably has a smaller adhesive force between the photosensitive layer 12 and the protective film 13 than the adhesive force between the photosensitive layer 12 and the support 11.

  Examples of the support 11 included in the photosensitive element 1 include a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  The thickness of the support 11 is preferably 5 to 100 μm, and more preferably 10 to 30 μm. If the thickness is less than 5 μm, the support 11 tends to be easily broken when the support 11 is peeled off from the photosensitive element 1 before development, and if it exceeds 100 μm, the resolution and flexibility tend to decrease. . In the present embodiment, since the photosensitive layer 12 is formed using the polyester resin as described above, when the thickness of the support 11 is larger than that of the conventional one, for example, when the thickness is more than 25 μm and not more than 100 μm. Can maintain its flexibility and resolution.

  The photosensitive element 1 composed of the three layers of the support 11, the photosensitive layer 12, and the protective film 13 as described above may be stored, for example, as it is, or may be rolled on the core with the protective film 13 interposed therebetween. It can be wound into a shape and stored.

  The photosensitive element of the present embodiment can exhibit sufficient storage stability that can maintain various properties such as coating properties, resolution of cured films, and thermal shock resistance even after being stored for a long time. . Further, since the surface of the photosensitive layer is less sticky, it is possible to efficiently produce a high-resolution and high-density printed wiring board.

  The method for forming a resist pattern of the present invention includes the photosensitive resin composition described above so as to cover a conductor layer on an insulating substrate of a laminated substrate having an insulating substrate and a conductor layer having a circuit pattern formed on the insulating substrate. A photosensitive layer containing the product is formed, an actinic ray is irradiated to a predetermined portion of the photosensitive layer to form an exposed portion, and then the portion of the photosensitive layer other than the exposed portion is removed. Hereinafter, preferred embodiments of the resist pattern forming method of the present invention will be described.

  Examples of the method for forming the photosensitive layer include a method in which the photosensitive resin composition of the present invention is directly applied, or a method in which the photosensitive layer in the photosensitive element is heated and bonded to an insulating substrate and laminated. When the photosensitive resin composition contains a volatile component such as a solvent, the photosensitive layer formed on the substrate is mainly composed of components after most of the solvent is removed. When the photosensitive element includes a protective film, the protective film is peeled off from the photosensitive element before forming the photosensitive layer.

  The surface of the insulating substrate on which the photosensitive layer is laminated is usually the surface of the conductor layer, but may be a surface other than the conductor layer. When the photosensitive layer in the photosensitive element is heated and laminated on the insulating substrate and laminated, the heating temperature of the photosensitive layer is preferably 70 to 130 ° C., and the pressure is about 0.1 to 1.0 MPa. The ambient pressure is more preferably 4 kPa or less, but these conditions are not particularly limited. Further, if the photosensitive layer is heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the insulating substrate and the conductor layer in advance. However, in order to further improve the stackability, the pre-heat treatment is performed. You can also.

  In this way, after the lamination of the photosensitive layer is completed, an exposure part is formed by irradiating a predetermined portion of the photosensitive layer with an actinic ray in an exposure step. Examples of the method for forming the exposed portion include a method of irradiating actinic rays in an image form through a negative or positive mask pattern called an artwork. At this time, when the support on the photosensitive layer is transparent, it can be irradiated with actinic rays as it is, but when it is opaque, it is irradiated with actinic rays after removing the support.

  As the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a xenon lamp that emits ultraviolet rays effectively is used. Moreover, what emits visible light effectively, such as a photographic flood light bulb and a solar lamp, is also used.

After the exposure, if a support is present on the photosensitive layer, the support is removed. Thereafter, portions other than the exposed portion of the photosensitive layer are developed and removed by wet development, dry development, or the like, and a resist pattern made of a cured product of the photosensitive resin composition is formed. In the case of wet development, development is performed by a known method such as spraying, rocking immersion, brushing, or scraping, using a developer corresponding to the photosensitive resin composition such as an alkaline aqueous solution, an aqueous developer, or an organic solvent. To do. Note that after the resist pattern is formed, post-curing may be further performed by exposure at 1 to 5 J / cm ² or / and heating at 100 to 200 ° C. for 30 minutes to 12 hours (post-heating step).

  As the developer, a developer that is safe and stable and has good operability is preferably used. For example, a dilute solution (1 to 5% by weight aqueous solution) of sodium carbonate at 20 to 50 ° C. is used. The developer used in the development process is not particularly limited as long as it selectively elutes the unexposed part without damaging the exposed part, and is determined by the development type of the resin composition, Common ones such as a semi-aqueous developer and a solvent developer can be used. For example, an emulsion developer containing water and an organic solvent as described in JP-A-7-234524 can be used. Particularly useful emulsion developers include, for example, propylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, 2,2-butoxyethoxyethanol, butyl lactate, cyclohexyl lactate, ethyl benzoate, and 3-methyl-3 as organic solvent components. An emulsion developer containing 10 to 40% by mass of an organic solvent such as methoxybutyl acetate can be mentioned. When an alkaline developer is used, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, 4-sodium borate, ammonia, amines and the above organic solvent are used. It is also possible to use an emulsion developer. → (Please instruct us to delete if unnecessary.)

  The resist pattern thus formed also functions as a protective film for the circuit wiring after the circuit wiring is soldered to the substrate. This resist pattern exhibits sufficiently high thermal shock resistance, mechanical properties such as tensile strength and elongation, electrical insulation, heat and humidity resistance, alkali resistance, solvent resistance, solder heat resistance and electrolytic Ni / Au resistance. Excellent plating ability. Therefore, it is useful as a permanent mask (solder resist) for semiconductor packages.

  The printed wiring board of this invention is equipped with an insulated substrate and the cured film of the above-mentioned photosensitive resin composition formed on the insulated substrate. Hereinafter, a preferred embodiment of the printed wiring board of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the printed wiring board of the present embodiment.

  The printed wiring board 2 shown in FIG. 2 has an insulating substrate 22, a conductor layer 23 having a circuit pattern formed on one surface of the insulating substrate 22, and a circuit pattern formed on the other surface of the insulating substrate 22. And a solder resist 241 formed on the insulating substrate 22 so as to cover the conductor layer 23 having a circuit pattern. The solder resist 241 is made of a cured film of the photosensitive resin composition, and the solder resist 241 has an opening 26 so that at least a part of the conductor layer 23 having a circuit pattern is exposed.

  Since the printed wiring board 2 has the opening 26, a mounting component such as CSP or BGA can be joined to the conductor layer 23 having a circuit pattern by solder or the like, and so-called surface mounting becomes possible. The solder resist 241 has a role as a solder resist for preventing the solder from adhering to unnecessary portions of the conductor layer during soldering for joining. Functions as a permanent mask for protecting the conductor layer 23.

  Next, an example of a method for manufacturing the printed wiring board 2 will be schematically described. FIG. 3 is a process diagram schematically showing a method of manufacturing the printed wiring board 2 shown in FIG. FIG. 3A shows a printed wiring board substrate 3 including a conductor layer 23 having a circuit pattern on one side and a conductor layer 21 having no circuit pattern on the other side, and FIG. 3 (c) and 3 (d) show the printed wiring board substrate 4 after the photosensitive layer 24 is laminated on the insulating substrate 22, the state in which the photosensitive layer 24 is irradiated with actinic rays, and the printed wiring after development. The plate 2 is shown.

  First, the pattern of the conductor layer 23 is formed on the insulating substrate 22 as shown in FIG. 3A by a known method of etching one side of a double-sided metal-clad laminate (for example, a double-sided copper-clad laminate). Then, the printed wiring board substrate 3 on which the conductor layer 23 is formed is obtained. Next, as shown in FIG. 3B, a photosensitive layer made of the photosensitive resin composition according to the present invention on the printed wiring board substrate 3 on which the conductor layer 23 is formed so as to cover the conductor layer 23. 24 is obtained, and the printed wiring board substrate 4 on which the photosensitive layer 24 is laminated is obtained. Next, as shown in FIG. 3C, a predetermined portion of the photosensitive layer 24 is cured by irradiating the laminated photosensitive layer 24 with actinic rays through the photomask 5 having a predetermined pattern. Finally, the printed wiring board 2 is obtained by removing a non-exposed portion (for example, alkali development) to form a solder resist 241 having an opening 26 as shown in FIG. In addition, when the photosensitive resin composition contains volatile components, such as an organic solvent, the soldering resist 241 is a cured film of the photosensitive resin composition after most of these volatile components are removed.

  In addition, lamination | stacking of the photosensitive layer 24 on the insulated substrate 22, irradiation of actinic light, and removal of an unexposed part can be performed by the method similar to the case in the formation method of the above-mentioned resist pattern.

  The solder resist 241 in the printed wiring board 2 obtained in this way is composed of a cured film (cured body) of the photosensitive resin composition of the present embodiment, and exhibits sufficiently high thermal shock resistance and tensile strength. Excellent mechanical properties such as strength and elongation, electrical insulation, heat and humidity resistance, alkali resistance, solvent resistance, solder heat resistance and electrolytic Ni / Au plating resistance. If the solder resist 241 is obtained by both light irradiation and heating, the above-described effects can be more effectively exhibited.

  The photosensitive resin composition of the present invention can also be used for a package substrate comprising an insulating substrate and an insulating film formed on the insulating substrate. In this case, a cured film of the photosensitive resin composition may be used as the insulating film.

When the cured film of the photosensitive resin composition is used as, for example, a solder resist for a printed wiring board, a flexible wiring board or a semiconductor package substrate, after completion of development in the above resist pattern forming method, solder heat resistance and chemical resistance In order to improve the above, it is preferable to perform ultraviolet irradiation or heating with a high-pressure mercury lamp. In the case of irradiating ultraviolet rays, the irradiation amount can be adjusted as necessary. For example, the irradiation can be performed at an irradiation amount of about 0.2 to 10 J / cm ² . Moreover, when heating a resist pattern, it is preferable to carry out for about 15 to 90 minutes in the range of about 100-170 degreeC. Furthermore, ultraviolet irradiation and heating can be performed at the same time, and after either one is performed, the other can be performed. When performing ultraviolet irradiation and heating simultaneously, it is more preferable to heat to 60 to 150 ° C. from the viewpoint of effectively imparting solder heat resistance, chemical resistance and the like.

  The substrate provided with the resist pattern in this manner is then mounted with a semiconductor element or the like (for example, wire bonding or solder connection), and is mounted on an electronic device such as a personal computer.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in another embodiment of the photosensitive element of the present invention, only the photosensitive layer 12 and the support 11 in FIG. 1 may be provided without the protective film.

  The printed wiring board of the present invention may be a multilayer printed wiring board in which a plurality of conductive layers and insulating layers are alternately laminated on the insulating substrate or on both sides of the insulating substrate. The cured film of the material functions as an interlayer insulating film for reliably insulating the conductive layers.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  The polyester resin (component (A)) of the present invention was prepared by the following method. First, in a flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, bisphenol A type epoxy resin (YD-011, manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 479 g / eq, trade name) 182.7 parts by mass Then, 64.0 parts by mass of cyclohexanone and 30.0 parts by mass of toluene were charged, and the mixture was stirred while being heated to 130 ° C. while blowing nitrogen gas, thereby performing reflux dehydration of moisture contained in the epoxy resin. Next, 34.9 parts by mass of tetrahydrophthalic acid (manufactured by Shin Nippon Rika Co., Ltd.) and 3.6 parts by mass of dimethyl paratoluidine (manufactured by Samsung Chemical Co., Ltd.) were added thereto, and the mixture was kept at 140 ° C. for 4 hours. Then, 108.0 parts by mass of tetrahydrophthalic anhydride (manufactured by Shin Nippon Rika Co., Ltd.) was added, and the mixture was kept at 120 ° C. for 3 hours to obtain a polyester resin as component (A). Thereafter, the polyester resin was diluted with 127.0 parts by mass of methyl ethyl ketone. The weight average molecular weight of the obtained polyester resin was 49000, the solid content was 57.0%, and the acid value was 133 mgKOH / g.

(Examples 1-5, Comparative Examples 1-6)
First, by mixing each component shown in Tables 1 and 2 at a blending ratio (mass standard, (D) component is a blending ratio as a liquid, and the other is a blending ratio as a solid content), the photosensitivity is obtained. A resin composition solution was obtained. In the table, resin (1) is a 65 mass% carbitol acetate / solvent naphtha solution of acid-modified bisphenol A type epoxy acrylate (ZAR-1035, Nippon Kayaku Co., Ltd., trade name). Resin (2) is dipentaerythritol hexaacrylate (DPHA) (Kayarad DPHA, trade name, manufactured by Nippon Kayaku Co., Ltd.), and resin (3) is bisphenol A polyoxyethylene dimethacrylate (BPE-10, Shin-Nakamura Chemical Co., Ltd., trade name), and component (C) is 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (I-369, Ciba Specialty Chemicals) Product name).

  In addition, component (D) is methyl ethyl ketone, and component (E) YX4000 is a biphenyl type epoxy resin (solubility: 27 g / 100 g methyl ethyl ketone, YX4000, Japan epoxy resin) as a compound having an epoxy group that is hardly soluble in a diluent. OXT-221 is a polyfunctional oxetane compound (Aron Oxetane OXT-221, manufactured by Toagosei Co., Ltd., trade name).

  Epicoat 1002 is a bisphenol A type epoxy resin (solubility: 50 g / 100 g methyl ethyl ketone, Epicoat 1002, manufactured by Japan Epoxy Resin Co., Ltd., trade name), and BL3175 is an isocyanurate methylethylketone oxime block containing hexamethylene diisocyanate as a base isocyanate. 75% by weight methyl ethyl ketone solution (BL3175, manufactured by Sumika Bayer Urethane Co., Ltd., trade name). The elastomer is a saturated polyester resin (SP1612, manufactured by Hitachi Chemical Co., Ltd., trade name).

  Next, a photosensitive layer is formed by uniformly coating the photosensitive resin composition solution on a 16 μm-thick polyethylene terephthalate (PET) film (G2-16, trade name, manufactured by Teijin Ltd.) as a support. Was dried at 100 ° C. for about 10 minutes using a hot air convection dryer. The film thickness after drying of the photosensitive layer was 25 μm.

  Subsequently, a polyethylene film (NF-13, product name, manufactured by Tamapoly Co., Ltd.) was bonded as a protective film on the surface of the photosensitive layer opposite to the side in contact with the support to obtain a photosensitive element.

  And the copper surface of the printed wiring board base material (E-679, the Hitachi Chemical Co., Ltd. make, brand name) which laminated | stacked 12-micrometer-thick copper foil on the glass epoxy base material is grind | polished with an abrasive brush, washed with water, and dried. did. Using a continuous vacuum laminator (HLM-V570, manufactured by Hitachi Chemical Co., Ltd., trade name) on the polished copper foil of the printed wiring board substrate, a heat shoe temperature of 100 ° C., a laminating speed of 0.5 m / min, and an atmospheric pressure Under the conditions of 4 kPa or less and a pressure bonding pressure of 0.3 MPa, the photosensitive element was laminated while peeling the polyethylene film so that the photosensitive layer and the copper foil were in close contact with each other to obtain a laminate for evaluation.

[Evaluation of light sensitivity]
A photo tool having a stove 21-step tablet as a negative is closely attached to the obtained PET film of the laminate for evaluation, and the stove 21-step is used by using an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. The exposure was performed with an energy amount such that the number of steps remaining after development of the tablet was 8.0. Subsequently, the evaluation laminate was allowed to stand at room temperature for 1 hour, the PET film was peeled off, developed by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 60 seconds, and further heated at 80 ° C. for 10 minutes ( Dried). The above-mentioned energy amount was used as a numerical value for evaluating photosensitivity. The lower this value, the higher the photosensitivity. The results are shown in Tables 3 and 4.

[Resolution evaluation]
PET of laminated body for evaluation comprising photo tool having stove 21 step tablet and photo tool having wiring pattern of line width / space width of 30/30 to 200/200 (unit: μm) as resolution evaluation negative The film was brought into close contact with the film, and exposure was performed using the above-described exposure apparatus with an energy amount such that the number of remaining step stages after development of the stove 21-step tablet was 8.0. Subsequently, the evaluation laminate was allowed to stand at room temperature for 1 hour, the PET film was peeled off, developed by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 60 seconds, and further heated at 80 ° C. for 10 minutes ( Dried). The resolution was evaluated based on the smallest value (unit: μm) of the space width between the line widths in which a rectangular resist shape was obtained by development processing. It shows that it is excellent in the resolution, so that this value is small. The results are shown in Tables 3 and 4.

[Evaluation of coating properties]
The PET film of the laminate was peeled off from the evaluation laminate without exposure, the finger was lightly pressed against the exposed photosensitive layer surface, and the degree of sticking to the finger was evaluated according to the following criteria. That is, “A” indicates that sticking to the finger is hardly or hardly recognized, and “B” indicates that sticking to the finger is recognized. The results are shown in Tables 3 and 4.

[Evaluation of solder heat resistance]
A photo tool having a stove 21-step tablet and a photo tool having a 2 mm square rectangular pattern as a negative are brought into close contact with the PET film of the laminate for evaluation, and the stove 21 is used by using the exposure machine described above. The exposure was performed with an energy amount such that the number of steps remaining after development of the stepped tablet was 8.0. Next, after standing at room temperature for 1 hour, the PET film of the laminate was peeled off, spray development was performed under the same developer and development conditions as in the photosensitivity evaluation, and heated (dried) at 80 ° C. for 10 minutes. . Subsequently, the photosensitive layer was irradiated with ultraviolet rays with an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Seisakusho. Further, the photosensitive layer was heat-treated at 160 ° C. (180 ° C. in Examples 4 and 5) for 60 minutes to obtain a package substrate for evaluation on which a solder resist having a 2 mm square rectangular opening was formed.

  Next, rosin-based flux (MH-820V, manufactured by Tamura Kaken Co., Ltd., trade name) was applied to the package substrate, and then immersed in a solder bath at 260 ° C. for 30 seconds to perform soldering.

  In this way, the crack generation state of the solder resist on the solder-plated package substrate, the degree of solder resist floating from the substrate, and the degree of peeling were visually observed and evaluated according to the following criteria. That is, “A” was given when no cracking of the solder resist was observed and no solder resist was lifted or peeled off, and “B” was given when any of them was observed. The results are shown in Tables 3 and 4.

[Evaluation of thermal shock resistance]
After the evaluation package substrate subjected to solder plating used for the evaluation of solder heat resistance is exposed to the atmosphere of −55 ° C. for 15 minutes, the temperature is increased at a temperature increase rate of 180 ° C./min, and then the temperature of 125 ° C. After being exposed to the atmosphere for 15 minutes, a heat cycle in which the temperature was lowered at a rate of temperature reduction of 180 ° C./min was repeated 1500 times. The crack and peeling degree of the solder resist on the evaluation package substrate after being exposed to such an environment were observed with a 100-fold metal microscope and evaluated according to the following criteria. That is, “A” indicates that the solder resist could not be cracked and peeled, and “B” indicates that any of them could be confirmed. The results are shown in Tables 3 and 4.

[Evaluation of electric corrosion resistance]
Etching was performed on the copper foil of a printed wiring board substrate (E-679, manufactured by Hitachi Chemical Co., Ltd., product name) in which a 12 μm thick copper foil was laminated on a glass epoxy substrate, and the line width / space width was 50 μm / A comb-shaped electrode on the same surface opposed to each other was obtained, which was 50 μm and the lines were not in contact with each other. Using a continuous vacuum laminator (HLM-V570, manufactured by Hitachi Chemical Co., Ltd., trade name) on the comb-shaped electrode of this substrate, a heat shoe temperature of 100 ° C., a laminating speed of 0.5 m / min, an atmospheric pressure of 4 kPa or less, and a pressure of pressure 0 Under the condition of 3 MPa, the photosensitive element was laminated while peeling the polyethylene film so that the photosensitive layer and the comb electrode were in close contact with each other, and a laminate for evaluating electric corrosion resistance was obtained under the same conditions as described above. .

A photo tool having a stove 21-step tablet as a negative is closely attached to the obtained PET film of the laminate for evaluation, and the stove 21-step is used by using an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. The exposure was performed with an energy amount such that the number of steps remaining after development of the tablet was 8.0. Subsequently, the evaluation laminate was allowed to stand at room temperature for 1 hour, the PET film was peeled off, developed by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 60 seconds, and further heated at 80 ° C. for 10 minutes ( Dried). Subsequently, using a UV irradiation device manufactured by Oak Manufacturing Co., Ltd., the photosensitive layer was irradiated with ultraviolet rays with an energy amount of 1 J / cm ² , and further subjected to heat treatment at 160 ° C. for 60 minutes to form a solder resist.

  After connecting the polytetrafluoroethylene shield wires to the comb electrodes with Sn / Pb solder so that a voltage is applied between the comb electrodes of the evaluation laminate after heating, 5 V is applied to the evaluation laminate. With the voltage applied, the evaluation laminate was allowed to stand in a super accelerated high temperature and high humidity life test (HAST) bath at 130 ° C. and 85% RH for 200 hours. Thereafter, the degree of migration of the solder resist in the evaluation laminate was observed with a 100-fold metal microscope, and evaluated according to the following criteria. That is, “A” indicates that the solder resist migration could not be confirmed, and “B” indicates that it was not confirmed. The results are shown in Tables 3 and 4.

[Evaluation of storage stability]
The photosensitive element obtained as described above was allowed to stand at 5 ° C. for 1 month in the air. Subsequently, the evaluation laminated body was obtained like the above using the photosensitive element after stationary. And the board | substrate for evaluation which formed the soldering resist which has a 2 mm square rectangular opening part was obtained like the thing in [Evaluation of solder heat resistance]. The pattern of the solder resist formed on the evaluation substrate was observed with a stereomicroscope, and “A” indicates that no resin remains in the unexposed area, and “B” indicates that resin remains. The results are shown in Tables 3 and 4.

[Evaluation of physical properties of cured film]
The photosensitive element which concerns on Examples 1-5 and Comparative Examples 1-6 was exposed and heated on the conditions similar to the above, and the cured film which hardened the photosensitive layer was obtained. The tensile strength and elongation of the cured film were measured according to JIS K 7127 “Plastic Film and Sheet Tensile Test Method”. The results are shown in Tables 3 and 4.

It is a schematic cross section which shows one Embodiment of the photosensitive element of this invention. It is a schematic cross section which shows one Embodiment of the printed wiring board of this invention. It is a schematic process drawing which shows one Embodiment of the manufacturing method of the printed wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 2 ... Printed wiring board 3, 4 ... Base material for printed wiring boards, 5 ... Photomask, 11 ... Support body, 12, 24 ... Photosensitive layer, 13 ... Protective film, 21 ... Circuit pattern Conductor layer not having, 22 ... insulating substrate, 23 ... conductor layer having circuit pattern, 26 ... opening, 241 ... solder resist.

Claims (6)

(A) the following general formula (1);

[Wherein, R ¹ represents a divalent organic group that is a diglycidyl ether type epoxy compound residue, R ² represents a divalent organic group that is a dibasic acid residue, and R ³ represents a hydrogen atom or General formula (2);

(In the formula, R ⁴ represents an acid anhydride residue.)
The group represented by these is shown. ]
A resin having a repeating unit represented by:
(B) a photopolymerizable compound having an ethylenically unsaturated group in the molecule;
(C) a photopolymerization initiator;
(D) a diluent;
(E) a compound having an epoxy group in the molecule which is hardly soluble in the diluent, and / or a polyfunctional oxetane compound;
Containing a photosensitive resin composition. (A) the following general formula (3);

[Wherein, R ¹ represents a divalent organic group that is a diglycidyl ether type epoxy compound residue, R ² represents a divalent organic group that is a dibasic acid residue, and R ³ represents a hydrogen atom or General formula (2);

(In the formula, R ⁴ represents an acid anhydride residue.)
And n represents an integer of 1 or more. ]
A resin represented by
(B) a photopolymerizable compound having an ethylenically unsaturated group in the molecule;
(C) a photopolymerization initiator;
(D) a diluent;
(E) a compound having an epoxy group in the molecule which is hardly soluble in the diluent, and / or a polyfunctional oxetane compound;
Containing a photosensitive resin composition.   The resin comprises a first step of obtaining an intermediate product by a polymerization reaction of a diglycidyl ether type epoxy compound and a dibasic acid, and a second step of adding an acid anhydride to the intermediate product. The photosensitive resin composition of Claim 1 or 2 obtained by a method.   In the first step, the diglycidyl ether type epoxy compound and the dibasic acid have an equivalent ratio of active hydrogen of the dibasic acid to an epoxy group of the diglycidyl ether type epoxy compound of 1.03 to 1. The photosensitive resin composition of Claim 3 mix | blended so that it may become 30.   The photosensitive resin composition according to claim 3 or 4, wherein the dibasic acid contains a dicarboxylic acid. A photosensitive element provided with a support body and the photosensitive layer which consists of the photosensitive resin composition as described in any one of Claims 1-5 formed on this support body.

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