KR101935609B1 - Photosensitive resin composition, photosensitive element, method for resist pattern formation, and method for manufacturing printed wiring board - Google Patents

Abstract

The present invention provides a photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator, wherein the component (A) (A3) from 1 to 20% by weight of a constitutional unit derived from a (meth) acrylic acid alkyl ester, and (b) from 50 to 80% by weight of a constituent unit derived from an acrylate derivative, And (a4) 5 to 30% by weight of a structural unit derived from (meth) acrylic acid.

Description

TECHNICAL FIELD [0001] The present invention relates to a photosensitive resin composition, a photosensitive element, a method of forming a resist pattern, and a method of manufacturing a printed wiring board. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to a photosensitive resin composition, a photosensitive element using the same, a method for forming a resist pattern, and a method for producing a printed wiring board.

2. Description of the Related Art In recent years, semiconductor packages such as a BGA (Ball Grid Array) used for mounting IC chips on a substrate have become multi-pinned and narrowed as the tendency toward thinning, small volume, It is required to increase the density of printed wiring boards.

BACKGROUND ART Conventionally, in the field of manufacturing printed wiring boards, resist materials used for etching, plating and the like include a support film, a photosensitive resin composition layer composed of a photosensitive resin composition laminated on the support film, and a photosensitive element Is widely used.

The printed wiring board is manufactured by the following method using a photosensitive element. First, the photosensitive resin composition layer is laminated (laminated) on the substrate while peeling off the protective film of the photosensitive element. Next, an exposed portion of the photosensitive resin composition layer is irradiated with an actinic ray to cure the exposed portion. After the support film is peeled off, the unexposed portion is removed (developed) from the substrate, and a resist pattern made of the cured product of the photosensitive resin composition is formed on the substrate. A circuit board is formed on a substrate on which a resist pattern is formed by performing an etching treatment or a plating treatment to form a circuit on the substrate, and finally removing the resist by peeling.

Particularly, in the manufacture of a semiconductor package mounted substrate, a semi-additive process (SAP) in which a plating process, a resist stripping, and a soft etching are performed after forming a resist pattern has become mainstream.

In the photosensitive resin composition used in the semi-additive process (SAP), it is required that fine wiring can be formed over a conventional photosensitive resin composition.

BACKGROUND ART [0002] A large number of photosensitive resin compositions capable of forming fine wirings (excellent in resolution and adhesiveness) have been proposed in the past (see, for example, Patent Documents 1 to 3).

Patent Document 1: JP-A-2005-301101 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-234995 Patent Document 3: Japanese Patent Application Laid-Open No. 2006-154740

However, even when the photosensitive resin composition described in Patent Document 1 or 2 is used, there is room for improvement in the resolution required recently. Further, the inventors of the present invention have found that the use of the photosensitive resin composition described in Patent Document 3 makes it possible to improve the resistance to the plating liquid at the end portions of the resist (hereinafter, (Hereinafter referred to as " plating resistance ") is low, and plating submergence occurs.

As a method for improving the plating resistance, a method of adding a hydrophobic compound to a resist or a method of improving the glass transition temperature is generally used. However, with these techniques, there is a problem that development scum is generated by the improvement of the hydrophobicity, adhesion of the remnant of the resist to the resist occurs, or resist flexibility is lowered by improvement of the glass transition temperature, and plating immersion is not improved The present inventors have discovered.

Further, the present inventors have tried to improve the resist flexibility by adding a hydrophilic compound to the resist. However, since the adhesion of the resist and the plating resistance are lowered, it is possible to form the fine wiring required for the SAP, It has been difficult to produce an excellent photosensitive resin composition.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photosensitive resin composition having excellent resolution and adhesiveness and good plating resistance, and a photosensitive element using the same, a method for producing a resist pattern, and a method for producing a printed wiring board.

A first aspect of the present invention is a photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator, wherein the component (A) (A3) a structural unit derived from a (meth) acrylic acid alkyl ester is referred to as 1 (meth) acrylate ester, To 20% by weight of (meth) acrylic acid, and (a4) 5 to 30% by weight of a constituent unit derived from (meth) acrylic acid.

Such a photosensitive resin composition is excellent in resolution and adhesion, and is also excellent in plating resistance. This is because the present inventors contemplate that the binder polymer contains a specific amount of a specific copolymerization component, thereby providing a resist having excellent balance of hydrophilicity and hydrophobicity.

A second aspect of the present invention is a photosensitive element comprising a support film and a photosensitive resin composition layer comprising the above-mentioned photosensitive resin composition formed on the support film.

A third aspect of the present invention is a method of manufacturing a photosensitive resin composition, comprising: a step of laminating a photosensitive resin composition layer comprising the photosensitive resin composition on a substrate; an exposure step of forming a light- And a developing step of removing the resin composition layer. In this aspect, the photosensitive resin composition layer may be laminated using a photosensitive element.

A fourth aspect of the present invention is a method for producing a printed wiring board in which a substrate on which a resist pattern is formed is subjected to an etching treatment or a plating treatment by the resist pattern formation method.

According to the present invention, it is possible to provide a photosensitive resin composition excellent in resolution and adhesion, excellent in plating resistance even on a thin plate substrate, and a photosensitive element using the same, a method for producing a resist pattern, and a method for producing a printed wiring board.

1 is a schematic cross-sectional view showing an embodiment of a photosensitive element of the present invention.

Hereinafter, one embodiment of the present invention will be described, but the present invention is not limited thereto. In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid, (meth) acrylate means acrylate and methacrylate corresponding thereto, and (meth) acryloyl group means acryloyl group And a methacryloyl group.

(Photosensitive resin composition)

The photosensitive resin composition of the present embodiment is a photopolymerizable compound having an ethylenically unsaturated bond (hereinafter, also referred to as " component (B) ") ), And (C) a photopolymerization initiator (hereinafter also referred to as " component (C) "). Hereinafter, the components (A) to (C) will be described in detail.

First, the (A) binder polymer will be described. The above-mentioned (A) binder polymer functions as a base material for imparting a film shape to a photosensitive element described later.

The (A) binder polymer is preferably a polymer comprising (a1) a constituent unit derived from a benzyl (meth) acrylate derivative, (a2) a constituent unit derived from a styrene derivative, (a3) a constituent unit derived from a ) (Meth) acrylic acid. The binder polymer containing these constituent units can be obtained by copolymerizing a monomer composition containing a monomer corresponding to each constituent unit, that is, a benzyl (meth) acrylate derivative, a styrene derivative, a (meth) acrylic acid alkyl ester, and (meth) . In the copolymer obtained as described above, each constituent unit may be randomly contained in the copolymer such as a so-called random copolymer, or a part of specific constituent units such as a block copolymer may exist locally Or may be a copolymer. Each of the constituent units may be a single type or plural types.

(A) The binder polymer contains (a1) a specific amount of a constitutional unit derived from a benzyl (meth) acrylate derivative, whereby the adhesiveness is excellent while maintaining the flexibility of the resin. Specific examples of benzyl (meth) acrylate derivatives include benzyl (meth) acrylate, 4-methylbenzyl (meth) acrylate, 4-ethylbenzyl (meth) acrylate, 4- Acrylate, 4-methoxybenzyl (meth) acrylate, 4-ethoxybenzyl (meth) acrylate, 4-hydroxylbenzyl (meth) acrylate and 4-chlorobenzyl (meth) acrylate.

The binder polymer (A) contains a specific amount of the structural unit derived from the styrene derivative (a2), whereby the adhesion and resolution of the fine line portion are excellent. Specific examples of the styrene derivatives include, for example, styrene, vinyl toluene, p-methyl styrene, and p-chlorostyrene.

(A) The binder polymer is excellent in both flexibility and toughness of the binder polymer by including a specific amount of the constituent unit derived from (a3) alkyl (meth) acrylate.

The alkyl group in the alkyl (meth) acrylate is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms in the straight or branched chain, and a straight chain or branched alkyl group having 1 to 4 More preferably an alkyl group, and particularly preferably a methyl group.

Specific examples of the alkyl (meth) acrylate ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl Butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate and 2-ethylhexyl (meth) acrylate.

(A) The binder polymer is excellent in alkali developability by containing a specific amount of the constituent unit derived from (a4) (meth) acrylic acid.

The binder polymer (A) may contain a structural unit other than the above (a1) to (a4).

The binder polymer (A) preferably contains (a1) 50 to 80% by weight of a structural unit derived from a benzyl (meth) acrylate derivative and 50 to 75% by weight More preferably 50 to 70% by weight, and still more preferably 50 to 65% by weight.

The binder polymer (A) preferably contains 5 to 40% by weight of (a2) structural units derived from a styrene derivative, and preferably contains 5 to 35% by weight in view of better adhesion and resolution. In addition, (a3) 1 to 20% by weight of a constitutional unit derived from an alkyl (meth) acrylate ester is contained, but it is preferably contained in an amount of 1 to 15% by weight in view of providing the resist with a more balanced hydrophilicity and hydrophobicity, By weight to 10% by weight, and more preferably 1 to 5% by weight. (A4) It contains 5 to 30% by weight of a structural unit derived from (meth) acrylic acid, but it preferably contains 5 to 25% by weight, more preferably 10 to 25% by weight Is more preferable.

The weight average molecular weight (Mw) of the binder polymer (A) is preferably 20,000 to 150,000, more preferably 30,000 to 100,000, even more preferably 40,000 to 80,000, and particularly preferably 40,000 to 60,000. From the viewpoint of more excellent tenting reliability, the Mw is preferably 20,000 or more, more preferably 30,000 or more, and even more preferably 40,000 or more. On the other hand, from the viewpoint of more excellent developability and resolution, it is preferably 150,000 or less, more preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 60,000 or less. In the present invention, Mw means a weight average molecular weight in terms of standard polystyrene by gel permeation chromatography (GPC).

The acid value (mgKOH / g) of the binder polymer (A) is preferably from 13 to 78, more preferably from 39 to 65, and even more preferably from 52 to 62. In the present specification, the acid value represents the number of mg of potassium hydroxide per 1 g of the binder polymer in the solution, and the measurement method is the same as that described in the examples.

The photosensitive resin composition of the present embodiment can be used in combination with a conventionally known binder polymer in addition to the binder polymer containing the specified amounts of (a1) to (a4).

The photopolymerizable compound having an ethylenically unsaturated bond (B) can be used without particular limitation as far as it is capable of photo-crosslinking. Specific examples thereof include bisphenol A (meth) acrylate compounds, hydrogenated bisphenol A (meth) acrylate compounds, polyalkylene glycol (meth) acrylates, urethane monomers, pentaerythritol , And trimethylolpropane (meth) acrylate. These may be used alone or in combination of two or more.

Above all, it is preferable to include a bisphenol A di (meth) acrylate compound from the viewpoint of improving resolution and plating resistance. As the bisphenol A based di (meth) acrylate compound, for example, there can be mentioned a compound represented by the following general formula (1).

[Chemical Formula 1]

In the above formula (1), each R independently represents a hydrogen atom or a methyl group. EO and PO each represent an oxyethylene group or an oxypropylene group. m ₁ , m ₂ , n ₁ and n ₂ each represent 0 to 40, m ₁ + m ₂ (average value) is 1 to 40, and n ₁ + n ₂ is 0 to 20. EO and PO may be either on the phenolic hydroxyl group side. m ₁ , m ₂ , n ₁ and n ₂ represent the number of constitutional units. Therefore, it represents an integer value in a single molecule, and a rational number, which is an average value, as an aggregate of a plurality of kinds of molecules. Hereinafter, the same shall apply to the number of constituent units.

(1-1) m ₁ + m ₂ (average value) of not more than 5 and (1-2) m ₁ + m ₂ (average value) in the compound represented by the general formula (Average value) of 6 to 40 is preferably used in combination.

(1-1) As a compound having m ₁ + m ₂ (average value) of 5 or less, for example, BPE-200 manufactured by Shin Nakamura Kagaku Co., Ltd. having m ₁ + m ₂ (average value) 1-2) As a compound having m ₁ + m ₂ (average value) of 6 to 40, for example, BPE-500 manufactured by Shin Nakamura Kagaku Co., Ltd. having m ₁ + m ₂ (average value)

Further, it is preferable that the photopolymerizable compound (B) having an ethylenically unsaturated bond further contains a compound represented by the following formula (2) in addition to the bisphenol A di (meth) acrylate compound.

(2)

In the formula (2), R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom or a methyl group, EO and PO are as defined above, s ¹ represents 1 to 30, r ¹ and r ² each represent 0 to 30 , And r ¹ + r ² (average value) is 1 to 30.

Specific examples of the compound represented by the formula (2), R ¹⁴ and R ¹⁵ is a methyl ^{group, r 1 + r 2 = 4} ( mean value), s ¹ = 12 (average value) of the vinyl compound (Hitachi Car Seiko gyosaje, trade name: FA -023M).

(C) Photopolymerization initiator can be used without particular limitation, and specific examples thereof include benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N, Ethyl 4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) Aromatic ketones such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; Diethylanthraquinone, 2,3-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-di 2-methyl anthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl 1,4-naphthoquinone, 2,3-dimethyl anthraquinone Quinones; Benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoin compounds such as benzoin, methylbenzoin and ethylbenzoin; Benzyldimethyl ketal and the like, benzyl derivatives of 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole Diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (o-fluorophenyl) 2,4,5-triarylimidazole dimer such as p-methoxyphenyl) -4,5-diphenylimidazole dimer; Acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane, N-phenylglycine, N-phenylglycine derivatives and coumarin compounds.

These may be used alone or in combination of two or more.

Of these, in view of adhesion and sensitivity, 2,4,5-triarylimidazole dimer, more preferably 2- (O-chlorophenyl) -4,5-diphenylimidazole dimer is included .

The content of the binder polymer (A) in the photosensitive resin composition is preferably 40 to 80 parts by weight, more preferably 45 to 75 parts by weight, relative to 100 parts by weight of the total amount of the components (A) and (B) , And more preferably 50 to 70 parts by weight. But it is preferably 40 parts by weight or more, more preferably 45 parts by weight or more, further preferably 50 parts by weight or more from the viewpoint of more excellent film property when used as a photosensitive element. From the viewpoint of more excellent photosensitivity, the amount is preferably 80 parts by weight or less, more preferably 75 parts by weight or less, and even more preferably 70 parts by weight or less.

The content of the photopolymerization initiator (C) in the photosensitive resin composition is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the total amount of the component (A) and the component (B) from the viewpoint of excellent photosensitivity and internal curability More preferably from 0.1 to 4.5 parts by weight, and still more preferably from 1 to 4 parts by weight.

The photosensitive resin composition may contain, if necessary, a photopolymerizable compound having at least one cyclic ether group capable of cationic polymerization in the molecule, a cation polymerization initiator, a sensitizer, a dye such as malachite green, tribromomethylphenylsulfone, Additives such as pigments, fillers, defoaming agents, flame retardants, stabilizers, adhesion promoters, leveling agents, release promoters, antioxidants, fragrances, emulsifiers and heat crosslinking agents are added You can. When these additives are added to the photosensitive resin composition, the content thereof may be about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B). These may be used alone or in combination of two or more.

The total content of the components (A), (B) and (C) in the photosensitive resin composition is preferably 90% by weight or more, more preferably 95% by weight or more based on the total solid content of the photosensitive resin composition.

The photosensitive resin composition may contain an organic solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide and propylene glycol monomethyl ether, It may be dissolved in a mixed solvent and used as a solution having a solid content of about 30 to 60% by weight.

The photosensitive resin composition is not particularly limited, but may be applied on a metal surface such as copper, a copper-based alloy, iron or an iron-based alloy as a liquid resist, dried and then coated with a protective film if necessary, .

(Photosensitive element)

Hereinafter, the photosensitive element of this embodiment will be described with reference to Fig. The photosensitive element 1 of the present embodiment includes a support film 10 and a photosensitive resin composition layer 20 made of the above-described photosensitive resin composition. The photosensitive resin composition layer 20 is provided on the first main surface 12 of the support film 10. The support film 10 has a second main surface 14 on the side opposite to the first main surface 12. A protective film may be provided on the surface of the photosensitive resin composition layer 20 opposite to the support film 10. Further, in the photosensitive resin composition layer, the photosensitive resin composition is in an uncured state.

The thickness of the photosensitive resin composition layer 20 varies depending on the application, but it is preferably about 1 to 100 mu m in thickness after drying. It is preferably 5 to 50 占 퐉, more preferably 5 to 30 占 퐉 in terms of being used in the semi-additive method (SAP).

As the support film 10, for example, a film made of a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, or polyester can be used. The thickness of these polymer films is preferably 1 to 100 mu m.

The photosensitive resin composition layer 20 can be obtained by applying the photosensitive resin composition described above onto the support film 10 and drying the solution. The application can be carried out by a known method such as roll coater, comma coater, gravure coater, air knife coater, die coater, bar coater and the like. The drying can be carried out at 70 to 150 ° C for about 5 to 30 minutes.

The photosensitive element 1 may be provided with an intermediate layer or a protective layer such as a cushion layer, an adhesive layer, a light absorbing layer and a gas barrier layer in addition to the photosensitive resin composition layer 20, the support film 10 and the protective film.

The photosensitive element 1 is wound, for example, as it is or wound on a cylindrical core in a state in which the protective film is further laminated. Also, at this time, it is preferable that the support film 10 is wound to the outside. It is preferable that a cross-section separator is provided on the end face of the roll-shaped photosensitive element roll in view of the cross-sectional protection, and it is preferable to provide a moisture-proof cross-section separator in view of the edge fusion. Further, it is preferable that the packaging method is wrapped in a black sheet having low moisture permeability as a wrapping method.

(Method of forming resist pattern)

As a method of forming a resist pattern using the photosensitive element 1, for example, the following methods can be mentioned.

When the protective film is present, the protective film is removed, and the photosensitive resin composition layer 20 is pressed and bonded to the substrate at a pressure of about 0.1 to 1 MPa (about 1 to 10 kgf / cm ² ) while heating to about 70 to 130 ° C , And a photosensitive resin composition layer are laminated. It is also possible to laminate under reduced pressure. The surface to be laminated is usually a metal surface, but there is no particular limitation.

The photosensitive resin composition layer 20 thus laminated is irradiated with active rays in the image plane through a negative or positive mask pattern. As the light source of the active light ray, a known light source, for example, a carbon arc, a mercury vapor arc, etc., a high pressure mercury lamp, a xenon lamp, or the like, which effectively emits ultraviolet rays or visible light is used.

As a method of exposure, a direct imaging exposure method in which digital data of a pattern is directly drawn on a photosensitive resin composition layer called DLP (Digital Light Processing) or LDI (Laser Direct Imaging) has been put to practical use, but the photosensitive resin composition Can be suitably used for the direct imaging exposure method. That is, the photosensitive resin composition of the embodiment of the present invention can be suitably used for the direct imaging exposure method. That is, one preferred embodiment of the present invention is a photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator, (A2) a structural unit derived from a styrene derivative in an amount of 5 to 40% by weight, (a3) a unit derived from a (meth) acrylic acid alkyl ester, (A4) a constituent unit derived from (meth) acrylic acid in an amount of 5 to 30% by weight, based on the total weight of the photosensitive resin composition.

When the support film 10 is present on the photosensitive resin composition layer after the exposure, the support film 10 is removed, and then the wet film is developed by a developing solution such as an alkaline aqueous solution, an aqueous developing solution or an organic solvent, The light portion is removed and developed to form a resist pattern.

Examples of the alkaline aqueous solution include a diluted solution of 0.1 to 5 wt% sodium carbonate, a diluted solution of 0.1 to 5 wt% of potassium carbonate, and a dilute solution of sodium hydroxide of 0.1 to 5 wt%. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to developability of the photosensitive resin composition layer. The alkaline aqueous solution may be mixed with a surface active agent, a defoaming agent, an organic solvent or the like. Examples of the developing method include a dip method, a spray method, blushing, scrapping, and the like.

As a post-development treatment, the resist pattern may be further cured by heating at about 60 to 250 DEG C or by exposure at about 0.2 to 10 J / cm < ² > When a printed wiring board is manufactured using the photosensitive element of the present embodiment, copper plating is performed using the developed resist pattern as a mask.

Next, the resist pattern can be peeled off into a strong alkaline aqueous solution, for example, than the alkaline aqueous solution used for development. As the strongly alkaline aqueous solution, for example, an aqueous solution of 1 to 10% by weight of sodium hydroxide, an aqueous solution of 1 to 10% by weight of potassium hydroxide and the like are used. Examples of the peeling method include an immersion method and a spray method.

(Manufacturing method of printed wiring board)

The method for producing a printed wiring board according to the present embodiment is carried out by etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern. Here, the etching treatment or the plating treatment of the substrate is carried out by etching or plating the surface of the substrate by a known method using the developed resist pattern as a mask.

The photosensitive resin composition of the present invention can be suitably used when a circuit substrate is formed on a package base material or a copper-clad laminate for a flexible printed wiring board, for which a thinness is required.

As the etching solution used for the etching, for example, a cupric chloride solution, a ferric chloride solution, and an alkali etching solution can be used. Examples of the plating include copper plating, solder plating, nickel plating, and gold plating.

After the etching or plating, the resist pattern can be peeled off with, for example, a strong alkaline aqueous solution rather than the alkaline aqueous solution used for development. As the alkaline aqueous solution, for example, a 1 to 10 wt% aqueous solution of sodium hydroxide and a 1 to 10 wt% aqueous solution of potassium hydroxide are used. Examples of the peeling method include an immersion method and a spray method. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board or a small-diameter through hole.

Further, when plating is performed on a substrate for circuit formation having an insulating layer and a conductor layer formed on the insulating layer, it is necessary to remove the conductor layer other than the pattern. Examples of the removing method include a method in which a resist pattern is peeled off and then lightly etched, a method in which soldering is performed subsequent to the plating, a resist pattern is then peeled off, the wiring portion is masked with solder, And a method of treating only the layer using an etchable etching liquid.

The photosensitive resin composition of the present embodiment can be suitably used for producing a printed wiring board as described above. That is, one preferred embodiment of the present invention is a photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator, (A2) a structural unit derived from a styrene derivative in an amount of 5 to 40% by weight, (a3) a unit derived from a (meth) acrylic acid alkyl ester, 1 to 20% by weight of a constituent unit, and (a4) 5 to 30% by weight of a constitutional unit derived from (meth) acrylic acid, in the production of a printed wiring board of a photosensitive resin composition.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples at all.

(Examples 1 to 5 and Comparative Examples 1 to 4)

(Preparation of photosensitive resin composition solution)

The components (A), (B), (C), additives and a solvent shown in Table 1 were blended to obtain a photosensitive resin composition solution. Further, the binder polymer in the component (A) is obtained by the following method.

[Synthesis of binder polymer]

A mixed solution obtained by dissolving 0.6 g of azobisisobutyronitrile in the polymerizable monomers (a1) to (a4) shown in Table 2 was referred to as " solution a ".

To a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introducing tube, 100 g of a mixed liquid (weight ratio 3: 2) of 60 g of methylcellosolve and 40 g of toluene was introduced. While nitrogen gas was blown into the flask, And the temperature was raised to 80 캜.

The solution a was dropped into the mixed solution in the flask over a period of 4 hours, and the dropwise dropwise addition was carried out with a mixture solution of 6 g of methyl cellosolve and 4 g of toluene (weight ratio 3: 2) Lt; 0 > C for 2 hours. Next, a solution prepared by dissolving 0.2 g of azobisisobutylonitrile in a mixed solution of 6 g of methylcellosolve and 4 g of toluene (weight ratio 3: 2) was added dropwise to the solution in the flask over 10 minutes, and then 18 g of methyl cellosolve and And 12 g of toluene (weight ratio 3: 2) were added dropwise over 10 minutes, and the solution in the flask was kept at 80 DEG C for 3 hours with stirring. Further, the solution in the flask was heated to 90 占 폚 over 30 minutes, kept at 90 占 폚 for 2 hours, and cooled to obtain a solution of each binder polymer.

The weight average molecular weight was determined by gel permeation chromatography (GPC) and calculated by using a calibration curve of standard polystyrene. The conditions of GPC are shown below.

GPC conditions

Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd.)

Column: 3 total less

Gelpack GL-R420

Gelpack GL-R430

Gelpack GL-R440 (manufactured by Hitachi Chemical Co., Ltd., trade name)

Eluent: tetrahydrofuran

Measuring temperature: 40 ° C

Flow rate: 2.05 mL / min

Detector: Hitachi L-3300 type RI (manufactured by Hitachi, Ltd.)

(Acid value measurement)

0.5 g of the solution of the binder polymer synthesized in the Erlenmeyer flask was weighed and 30 ml of a mixed solvent (weight ratio: toluene / methanol = 70/30) was added to dissolve the solution. Then, a phenolphthalein solution was added as an indicator, And the acid value was measured.

[Table 1]

BPE-500: bisphenol A dimethacrylate having an average of 10 moles of polyoxyethylene (trade name, manufactured by Shin Nakamura Kagaku Co., Ltd.)

BPE-200: bisphenol A dimethacrylate having an average of 4 moles of polyoxyethylene (trade name, manufactured by Shin Nakamura Kagaku Co., Ltd.)

FA-023M: dimethacrylate (manufactured by Hitachi Kasei Corporation) having an average of 12 moles of polyoxypropylene and an average of 3 moles of polyoxyethylene added to both ends thereof,

[Table 2]

(Preparation of photosensitive element)

Next, the obtained photosensitive resin composition solution was uniformly coated on a polyethylene terephthalate film (trade name " G2-16 ", manufactured by Teijin Co., Ltd.) having a thickness of 16 탆 and dried with a hot air convection type drier at 100 캜 for 10 minutes Thereafter, a photosensitive element was obtained by protecting with a polyethylene film (trade name: "NF-15A", manufactured by Tamapoly Co., Ltd.) having a thickness of 28 μm. The thickness of the photosensitive resin composition layer after drying was 15 占 퐉.

(Formation of Resist Pattern)

Next, the copper surface of the copper clad laminate for printed wiring boards (MCL-E679, trade name, manufactured by Hitachi Chemical Co., Ltd.) is roughened, subjected to alkali degreasing, pickling and rinsing, , And the resulting substrate was heated to 80 占 폚. The above-mentioned photosensitive resin composition layer was laminated on the copper surface at a speed of 1 m / min using a heat roll at 100 캜 while peeling the polyethylene film, to obtain a laminate for evaluation.

≪ Evaluation of photosensitivity &

Exposure was carried out using an exposure machine (trade name "EXM-1201", manufactured by Oak Co.) having a high-pressure mercury lamp, with a stopper 21 stage step tablet being adhered as a negative on the evaluation laminate. Next, the polyethylene terephthalate film was peeled off, and an unexposed portion was removed by spraying (spraying (developing time): twice the minimum developing time) at 30 DEG C with a 1 wt% sodium carbonate aqueous solution. Thereafter, the number of steps (X / 21) of the step tablet of the photocured film formed on the copper clad laminate was measured, and the exposure amount (mJ / cm ² ) indicating ST = 5/21 was taken as the photosensitivity value. The smaller this value is, the higher the photosensitivity is.

≪ Evaluation of adhesion &

A glass phototool having a wiring pattern with a line width of 1 to 30 (unit: 占 퐉) as a negative was brought into close contact with the above evaluation multilayer body, and pattern exposure was performed by an amount of energy at which the remaining step number after development became ST = did. Next, the polyethylene terephthalate film was peeled off, and an unexposed portion was removed by spraying (spraying (developing time): twice the minimum developing time) at 30 DEG C with a 1 wt% sodium carbonate aqueous solution. Thereafter, observation was made using an optical microscope, and the adhesion was evaluated. The value of the adhesion is represented by the smallest value among the line widths (占 퐉) left without being peeled off by the developing treatment, and the smaller the value, the higher the adhesion.

≪ Evaluation of resolution >

A glass phototool having a line width / space width of 1/1 to 30/30 (unit: 占 퐉) having a wiring pattern as a negative was brought into close contact with the evaluation laminate, and the remaining step number after development was ST = 5/21 Pattern exposure was performed by an amount of energy. Next, the polyethylene terephthalate film was peeled off, and an unexposed portion was removed by spraying (spraying (developing time): twice the minimum developing time) at 30 DEG C with a 1 wt% sodium carbonate aqueous solution. Thereafter, observation was made using an optical microscope to evaluate the resolution. The value of the resolution is represented by the smallest value among the space widths (占 퐉) in which the unexposed portions can be completely removed by the developing process, and the smaller the value, the higher the resolution.

≪ Evaluation of plating resistance &

1 to 30/30 (unit: 占 퐉) as a negative pattern on a laminate for evaluation prepared by laminating a photosensitive resin composition layer on a copper-clad laminate for flexible printed circuit boards (trade name "F30VC1" , And pattern exposure was performed by an amount of energy at which the number of remaining steps after development became ST = 5/21. Next, the polyethylene terephthalate film was peeled off, and a 1 wt% sodium carbonate aqueous solution was sprayed (spraying (developing time): twice the minimum developing time) at 30 ° C to remove unexposed portions to obtain a substrate for evaluation. The evaluation board was subjected to acid degreasing, washing with water and sulfuric acid dipping in this order, and copper plating treatment was carried out using copper sulfate plating solution until the plating thickness became 12 탆 under the condition of 1 A / dm ² . After washing with water and drying, the resist was peeled off and the immersion width of the plating was measured using an optical microscope from above. The value of the plating resistance is evaluated by the plated immersion width, and the smaller the value, the better the copper plating resistance.

<Flexibility>

The laminate for evaluation prepared by laminating the photosensitive resin composition layer to a copper-clad laminate for flexible printed circuit boards (trade name "F30VC1", manufactured by Nikkochemical Co., Ltd.) was cut into a size of 30 mm x 150 mm square, = 5/21 by the amount of energy. Next, the polyethylene terephthalate film was peeled off and a 1 wt% sodium carbonate aqueous solution was sprayed at 30 DEG C (spraying (developing time): twice the minimum developing time). The obtained sample was subjected to a Gardner-type mandrel bending tester to measure a maximum diameter at which cracks did not occur in the resist. The smaller the diameter, the better the flexibility.

[Table 3]

As apparent from Table 3, Examples 1 to 5 using the photosensitive resin composition of the present invention are excellent in flexibility and plating resistance, and exhibit sufficient photosensitivity, adhesion and resolution.

One … Photosensitive element, 10 ... Support film, 20 ... Photosensitive resin composition layer.

Claims (5)

A photosensitive resin composition comprising (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator,
Wherein the component (A) comprises (a1) 50 to 80% by weight of a structural unit derived from a benzyl (meth) acrylate derivative, (a2) 5 to 40% by weight of a structural unit derived from a styrene derivative, 1 to 20% by weight of a constituent unit derived from an alkyl acrylate and (a4) 5 to 30% by weight of a constituent unit derived from a (meth) acrylic acid,
The acid value (mgKOH / g) of the component (A) is from 13 to 78. A photosensitive element comprising a support film and a photosensitive resin composition layer comprising the photosensitive resin composition according to claim 1 formed on the support film. A lamination step of laminating a photosensitive resin composition layer comprising the photosensitive resin composition according to claim 1 on a substrate;
An exposure step of forming a light-cured portion in the photosensitive resin composition layer,
A developing step of removing the photosensitive resin composition layer other than the light-
And forming a resist pattern on the resist pattern. A lamination step of laminating the photosensitive element according to claim 2 on the substrate in the order of the photosensitive resin composition layer and the support film;
An exposure step of forming a light-cured portion in the photosensitive resin composition layer,
A developing step of removing the photosensitive resin composition layer other than the light-
And forming a resist pattern on the resist pattern. A method for producing a printed wiring board, wherein a substrate on which a resist pattern is formed is subjected to an etching treatment or a plating treatment by the method for forming a resist pattern according to claim 3 or 4.

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