KR20160080408A - Photosensitive resin composition for Dry Film Photoresist - Google Patents

Abstract

The present invention relates to a photosensitive resin composition for dry film photoresist. More specifically, the composition comprises a photopolymerization initiator, an alkali developing binder polymer, and a photopolymerizable compound. The photopolymerizable compound has two or more ethylenically unsaturated bonds, and thus is excellent in tolerance in terms of a plating solution, in particular, has an advantage in a fast stripping speed at the time of stripping.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition for dry film photoresists,

The present invention relates to a photosensitive resin composition for a dry film photoresist, and more particularly to a photosensitive resin composition for a dry film photoresist comprising a photopolymerization initiator, an alkali developable binder polymer, and a photopolymerizable compound.

The photosensitive resin composition is used in the form of a dry film photoresist (hereinafter referred to as DFR) or a liquid photoresist used in a printed circuit board (hereinafter referred to as a PCB) or a lead frame. Such a photosensitive resin composition is applied on a substrate to a predetermined thickness, and then subjected to a developing process for selectively irradiating light to form a desired circuit and then forming a desired circuit by a solvent. After the developing process, the substrate is etched according to the process Or a process of plating the substrate portion using a metal is performed.

It is important that the photosensitive resin composition has low stain resistance to plating. If the photosensitive resin composition contaminates the plating solution, discoloration may occur on the outer surface of the substrate subjected to the plating treatment or the plating efficiency may be lowered, which may cause disconnection.

Further, the photosensitive resin composition is required to have a peeling property after curing. In the case where the delamination characteristics are insufficient, it is difficult to peel the resist between fine wirings in the resist stripping process after the plating process, so that the stripping time is increased and the production efficiency is lowered. In terms of workability and productivity, the peeling speed is preferably high.

With this related technology, Korean Patent Laid-Open Publication No. 2012-0157531 discloses a technique of applying a photopolymerizable compound containing n-phenylglycine, but it has been found that the resolution is not sufficiently satisfied.

Accordingly, it is an object of the present invention to provide a photosensitive resin composition for a dry film photoresist, which is excellent in resistance to a plating solution and has an advantage of a rapid peeling speed particularly in peeling.

A first preferred embodiment according to the present invention is a photosensitive composition comprising 2 to 10% by weight of a photopolymerization initiator [A], 40 to 70% by weight of an alkali developable binder polymer, and 10 to 50% by weight of a photopolymerizable compound [C] And the photopolymerizable compound is a compound having two or more ethylenic unsaturated bonds.

The photopolymerizable compound according to the first embodiment may be a compound represented by the following general formula (1).

≪ Formula 1 >

Wherein l + n is from 2 to 4 and m is from 6 to 18.

The compound represented by Formula 1 may be contained in an amount of 10 to 100% by weight based on the total weight of the photopolymerizable compound.

The alkali developable binder polymer according to the first embodiment has an average molecular weight of 30,000 to 150,000 and a glass transition temperature of 60 to 150 ° C.

The photosensitive resin composition for a dry film photoresist according to the present invention has an advantage of a rapid peeling rate at the time of peeling and is excellent in both developability and fine line adhesion and particularly excellent in resistance to a plating solution and can be easily applied to a dry film photoresist .

According to an embodiment of the present invention, there is provided a photopolymerizable composition comprising: [A] 2 to 10 wt% of a photopolymerization initiator; [B] 40 to 70 wt% of an alkali developable binder polymer; and 10 to 50 wt% The photopolymerizable compound is a compound having two or more ethylenic unsaturated bonds, and can provide a photosensitive resin composition for a dry film photoresist.

In the present invention, when the composition of the present invention is applied to a dry film photoresist by using a compound represented by the following formula (1) as a compound having at least two ethylenic unsaturated bonds as a photopolymerizable compound, the hydrophobicity is improved, The resistance to the plating solution can be remarkably increased and the peeling speed can be increased.

≪ Formula 1 >

Wherein l + n is from 2 to 4 and m is from 6 to 18.

In addition, the polyamide resin composition may further include solvents and other additives (plasticizers, stabilizers, leveling agents, etc.) within the range not impairing the object of the present invention.

Hereinafter, the present invention will be described in more detail.

[A] Photopolymerization initiator

The photopolymerization initiator in the photosensitive resin composition is a substance that initiates a chain reaction of a photopolymerizable monomer by UV and other radiation and is a compound that plays an important role in the curing of a dry film resist.

Examples of the compound that can be used as such a photopolymerization initiator include anthraquinone derivatives such as 2-methyl anthraquinone and 2-ethyl anthraquinone; And benzoin derivatives such as benzoin methyl ether, benzophenone, phenanthrenequinone, and 4,4'-bis- (dimethylamino) benzophenone.

Methyl-1- [4- (methylthio) phenyl] -2-morpholino-2-ylmethoxy} Propan-1-one, 2-benzyl-2-dimethylamino-1- [4-morpholinophenyl] butan- , 4,6-trimethylbenzoyldiphenylphosphine oxide, 1- [4- (2-hydroxymethoxy) phenyl] -2-hydroxy-2-methylpropan- 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 3,3-dimethyl-4-methoxybenzophenone, benzophenone, 1- 2-methylpropan-1-one, 1- (4-dodecylphenyl) -2hydroxy- Dimethyl aminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-iso Methyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzylketone dimethyl acetal, benzyl ketone? -Methoxydiethyl acetal, 1-phenyl-1,2-propyldioxime-o, Benzoyl benzoate, bis [4-dimethylaminophenyl) ketone, 4,4'-bis (diethylamino) benzophenone, 4,4'-dichlorobenzophenone, benzyl Benzoin, methoxybenzoin, ethoxybenzoin, isopropoxybenzoin, n-butoxybenzoin, isobutoxybenzoin, tert-butoxybenzoin, p-dimethylaminoacetophenone, p- Butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone,?,? -Dichloro-4- Phenone, and pentyl 4-dimethylaminobenzoate may be used as a photopolymerization initiator.

When the content of the photopolymerization initiator is less than 2% by weight, the photopolymerization initiator has a low light efficiency and requires a large amount of exposure, resulting in extremely low production efficiency. When the content of the photopolymerization initiator exceeds 10% by weight, the film becomes brittle, There is a problem of causing defects of

[B] Alkali developable binder polymer

The binder polymer of the present invention is an alkali developable binder polymer which is a copolymer of (meth) acrylic acid and (meth) acrylic acid ester.

Specifically, it is a copolymer acrylic acid polymer obtained through copolymerization of two or more monomers selected from the following; Acrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, Linear acrylic acid polymers polymerized with 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, styrene monomers and? -Methylstyrene.

The alkali developable binder polymer of the present invention preferably has an average molecular weight of 30,000 g / mol to 150,000 g / mol in consideration of the coating property, followability of the dry film resist, and mechanical strength of the resist itself after formation of the circuit. If the average molecular weight is less than 30,000 g / mol, the property of spreading becomes strong, which is not suitable for use as a coating film, and the stain resistance may be deteriorated. The developing time is prolonged as the temperature is lowered, which may result in a decrease in production yield and a deterioration in resolution.

If the glass transition temperature of the binder polymer is lower than 60 ° C, it may be difficult to form the film due to tacky property during the liquid preparation with the photopolymerizable monomer. If the glass transition temperature exceeds 150 ° C, the binder polymer may brittle and break during film formation , The acid value becomes high and the film stability may deteriorate, which is not preferable

If the content of the alkali developable binder polymer is less than 40% by weight based on the entire photosensitive resin composition, development stage contamination may occur and shortcomings such as short circuit may occur. If the content exceeds 70% by weight, There may be a problem in that the circuit properties such as the breakdown voltage become poor.

[C] Photopolymerizable compound having an ethylenic unsaturated bond in a molecule

In the present invention, the photopolymerizable compound may be represented by a photopolymerizable oligomer or a photopolymerizable monomer.

The photopolymerizable compound of the present invention may be used alone or in combination with at least one monomer having at least two ethylene groups at the terminal thereof.

≪ Formula 1 >

Wherein l + n is from 2 to 4 and m is from 6 to 18.

The above Formula 1 plays a role in improving the hydrophobicity of the compound. By improving the hydrophobicity as described above, the resistance to the developing solution and the plating solution is remarkably increased and the peeling speed is increased.

The photopolymerizable oligomer of the present invention may contain a monomer having at least two ethylene groups at the terminal thereof in addition to the compound represented by the above formula (1). Examples of the monomer having at least two ethylene groups at the terminal thereof include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, But are not limited to, propylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, trimethyolpropane trimethacrylate, glycerin dimethacrylate, pentaerythritol dimethacrylate, 1,6-hexane glycol dimethacrylate, (pentaerythritol dimethacrylate), pentaerythritol trimethacrylate Pentaerythritol trimethacrylate, dipentaerythritol pentamethacrylate, 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 2 (2-hydroxy-3-methacryloyloxypropyl methacrylate), ethylene glycol diglycidyl ether dimethacrylate, diethylene glycol diglycidyl ether dimethacrylate, But are not limited to, diethylene glycol diglycidyl ether dimethacrylate, phthalic acid diglycidyl ester dimethacrylate, glycerin polyglycidyl ether polymethacrylate, And polyfunctional (meth) acrylates containing a urethane group.

The content of the photopolymerizable oligomer is preferably 10 to 50% by weight in the photosensitive resin composition. When the content of the photopolymerizable oligomer is within the above range, the effect of enhancing photosensitivity, resolution and adhesion can be obtained.

The compound represented by Formula 1 is contained in an amount of 10 to 100% by weight based on the total weight of the photopolymerizable compound. When the compound of Formula 1 is contained in an amount of less than 10% by weight based on the total weight of the photosensitive resin composition, The effect may be minimal compared to the amount.

In the example of the present invention, TM2207 (Tronyl) was used.

<Solvents and other additives>

As the solvent for the photosensitive resin composition of the present invention, a solvent selected from among methyl ethyl ketone (MEK), methanol, THF, toluene, acetone and ethyl acetate is generally used. Further, the photosensitive resin composition of the present invention is usually added in addition to the above-mentioned composition. Stabilizers, leveling agents and the like. The specific components and their contents are not particularly limited, but are usually added.

In the present invention, a dry film photoresist resin composition having the above composition is prepared, a photosensitive resin layer having a thickness of 5 to 200 탆 is coated on a conventional base film such as polyethylene terephthalate by a conventional coating method, And dried. The dried photosensitive resin layer is laminated using a conventional protective film such as polyethylene. Further, the dry film is exposed and developed to evaluate the properties of the respective films.

The dry film photoresist prepared using the composition according to the present invention has a fine line adhesion of less than 27 탆 and a resolution of not more than 38. It has a high stain resistance and a markedly rapid peeling speed and can be applied as a composition for a dry film photoresist have

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited by the examples.

[ Example ]

Example  1 to 3, Comparative Example  1, and 2

The photopolymerizable polyfunctional monomer, the photopolymerization initiator, the binder polymer and the additive were adjusted to have compositions as shown in the following Table 1, dried on a polyethylene terephthalate film, coated to a thickness of 40 탆, and dried. After drying, the polyethylene film was laminated with a protective film to prepare a dry film photoresist.

ingredient Product name (or ingredient name) Content (% by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Alkali developable binder polymer Methyl methacrylate / methyl methacrylate / styrene monomer / butyl acrylate copolymer (20/50/20/10 (weight ratio), weight average molecular weight 60,000, solids content 50%) 57.0 57.0 57.0 57.0 57.0 Photopolymerization initiator EAB ¹⁾ 0.5 0.5 0.5 0.5 0.5 BCIM ²⁾ 1.5 1.5 1.5 1.5 1.5 additive Toluenesulfonic acid monohydrate
(Aldrich Chemical) 0.5 0.5 0.5 0.5 0.5 Ruiko Crystal Violet
(Japan Hodogaya Co.) 0.3 0.3 0.3 0.3 0.3 Diamond Green GH
(Japan Hodogaya Co.) 0.2 0.2 0.2 0.2 0.2 Photopolymerizable compound TM2207 (Tronyl)
l + n = 3, m = 13 20.0 10.0 10.0 - - M2101 ^{3 )} - 10.0 - 20.0 - BPE-500 ⁴⁾ - - 10.0 - 20.0 Solvent Methyl (Ethyl Ketone)
(Aldrich Chemical, 99%). 20.0 20.0 20.0 20.0 20.0 (1) EAB: 4,4 '- (Bisdiethylamino) benzophenone (Aldrich Chemical)
(2) BCIM: 2,2'-Bis- (2-chlorophenyl-4,5,4'-tetraphenylbisimidazole (Aldrich Chemical)
(3) M2101: Bisphenol A (EO) 10 dimethacrylate (Miwon Specialty Chemical)
(4) BPE-500 (Shin Nakamura): 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane

The dry film photoresist prepared using the photosensitive resin composition prepared above was subjected to the following steps.

<Lamination>

A dry film photoresist was applied to a 1.6 mm thick copper clad laminate having a brush-polished surface, using a HAKUTO MACH (registered trademark) HAKUTO MACH Co., Ltd. under the conditions of a substrate preheating roll temperature of 120 캜, a laminator roll temperature of 115 캜, a roll pressure of 4.0 kgf / 610i. &Lt; / RTI &gt;

<Phenomenon and resolution>

The dry film photoresist laminated on the copper-clad laminate was irradiated with ultraviolet rays at an exposure dose of 40 mJ / cm ² using a Perkin-Elmer (TM) OB7120 (parallel light exposing machine) using a circuit evaluating photomask, and left for 15 minutes. Thereafter, the development was carried out under the development conditions of the spraying method with a 1.0 wt% aqueous solution of Na ₂ CO ₃ . The time taken until the dry film photoresist on the uncoated portion of the copper clad laminate was completely washed in the developing solution was measured using a stopwatch (minimum developing time), and the product was fixed at a breaking point of 50% ship).

Property evaluation

The properties of the dry film photoresist prepared using the photosensitive resin compositions prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2 below.

&Lt; Fine wire adhesion (unit: 占 퐉)

The ZEISS AXIOPHOT Microscope was used to measure the minimum line width at which independent resist remained after development.

<Resolution (unit: 탆)>

The space between the circuit and non-circuit lines was 1: 1 and measured with a ZEISS AXIOPHOT Microscope.

<Evaluation of Pollution Prevention for Plating>

The dry film photoresist made of the photosensitive resin composition was cut into a size of 40 cm x 50 cm and the protective film was removed. The step tablet was exposed at an exposure amount of 20 steps / 41 steps and the PET film was peeled to obtain a cured film. This cured film was immersed in 1 L of a plating solution of copper sulfate / sulfuric acid aqueous solution for 3 days. The copper plate was electrolytically copper plated at a current of 2A for 10 minutes using a Halsel test bath (manufactured by Precision Testers Lab.).

When the coating solution immersed in the cured film is used as the reference sample and the plating solution immersed in the cured film is observed, the appearance of the plating is visually observed to see if there is a plating appearance abnormality or gloss change. X, Respectively.

<Peeling speed>

The peeling speed was obtained by removing the PE film of the prepared photosensitive dry film resist and then laminating it on a copper plate using a heat press roller, exposing the photosensitive resin composition to light, and developing it to produce a photocured film having a size of 50 mm x 50 mm. And peeling was performed using a 3% sodium hydroxide aqueous solution (temperature: 50 ° C). The peel rate evaluation measured the time that the photocurable film fell off the copper plate.

division Fine wire adhesion ^{* 1} Resolution ^{* 2} Pollution of plating solution ^{* 3} Peeling speed (sec) Example 1 26 탆 32 탆 O 39 Example 2 24 탆 34 탆 O 51 Example 3 26 탆 38 탆 O 60 Comparative Example 1 22 탆 36 탆 X 65 Comparative Example 2 24 탆 44 탆 X 78

* 1 Fine wire adhesion is the minimum line width at which independent line widths survive development.

* 2 Resolution is measured with a 1: 1 space between the circuit and non-circuit lines

* 3 This is the result of copper plating and confirming the abnormality with reference sample.

As shown in Table 2, the peeling speed of Examples 1 to 3 is fast while maintaining the similar level of fine line adhesion and resolution as compared with the comparative examples. In addition, in Comparative Examples 1 and 2, the gloss disappeared, and it was found that Examples 1 to 3 were excellent in resistance to the plating solution.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereto will be. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (5)

[A] 2 to 10% by weight of a photopolymerization initiator, 40 to 70% by weight of an alkali developable binder polymer, and 10 to 50% by weight of a photopolymerizable compound [C] Wherein the composition is a compound having an unsaturated bond.
The method according to claim 1,
Wherein the photopolymerizable compound comprises a compound represented by the following general formula (1).
&Lt; Formula 1 >

Wherein l + n is from 2 to 4 and m is from 6 to 18.
The method according to claim 1,
The photosensitive resin composition for a dry film photoresist according to claim 1, wherein the compound represented by Formula 1 is contained in an amount of 10 to 100% by weight based on the total weight of the photopolymerizable compound.
The method according to claim 1,
Wherein the average molecular weight of the alkali developable binder polymer is from 30,000 to 150,000.
The method according to claim 1,
Wherein the alkali developable binder polymer has a glass transition temperature of 60 to 150 캜.