KR20180078696A - Photosensitive resin composition for dry film photoresist - Google Patents

Abstract

The purpose of the present invention is to provide a photosensitive resin composition for a dry film photoresist, the photosensitive resin composition which improves fine line adhesion and resolving properties by having resistance to a developer, particularly has excellent resistance to a plating solution, has a fast peel rate during peeling, inhibits a sludge generated in the developing process, and can perform an exposure process even with a small amount of exposure energy when using a laser direct exposure device. The present invention provides a photosensitive resin composition for a dry film photoresist, the photosensitive resin composition comprising a photopolymerization initiator [A], an alkali developable binder polymer [B], and a photopolymerizable compound [C] having an ethylenically unsaturated bond in a molecule, the photopolymerization initiator [A] includes n-phenylglycine, the photopolymerizable compound [C] having the ethylenically unsaturated bond in the molecule includes a compound represented by chemical formula 1; and the dry film photoresist comprising the photosensitive resin composition. In chemical formula 1, R_1 indicates a hydrogen atom or a methyl group, and R_2 indicates a hydrogen atom or tert-C_4H_9.

Description

[0001] 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 (DFR) or a liquid photoresist ink used for a printed circuit board (PCB) or a lead frame .

Currently, DFR is widely used not only for the manufacture of printed circuit boards and lead frames but also for the production of Rib barriers for plasma display panels (PDP), ITO electrodes for other displays, bus address electrodes, and black matrix production.

In manufacturing a PCB, a lead frame, etc., one of the most important processes is a process of forming a circuit on a copper clad lamination sheet (hereinafter referred to as CCLS) or a copper foil. The image transfer method used in this process is referred to as photolithography. The original image plate used for the photolithography is called Artwork (a term commonly used in a PCB and a lead frame manufacturing part), a photomask Quot; term commonly used in the manufacturing section).

Then, the image of the artwork has a portion where the light passes through and a portion that does not pass through the image, and the image is transferred using the portion. This image transfer process is called an exposure process.

The image of the artwork is transferred to the CCLS or copper foil by light transmission and non-penetration. At this time, the photoresist is the substance that forms the image by receiving the light. The photoresist should therefore be laminated or coated on the CCLS, copper foil before transferring the image of the artwork.

In the exposure process, typically, the photoresist is exposed to ultraviolet (UV) rays including an i-line (365 nm) emitted from a high-pressure mercury lamp in a PCB or a leadframe maker to polymerize and cure the exposed portion.

In recent years, direct drawing by laser, that is, maskless exposure which does not require artwork, has been rapidly diffused. As a light source for maskless exposure, light with a wavelength of 350 to 410 nm, particularly i-line (365 nm) or h-line (405 nm) is often used.

However, in comparison with the conventional ultra high-pressure mercury lamp exposure, maskless exposure requires a high-sensitivity photoresist that shortens the exposure time because of a long exposure time.

In recent years, the photosensitive resin composition has high sensitivity to ultra-high pressure mercury lamp or laser direct exposure, increases the resistance to a developing solution in the developing process, enables high-density circuit formation, and has excellent chemical resistance in the plating process And it is required to provide a photosensitive resin composition capable of reducing the amount of contamination of the plating solution, shortening the peeling time of the cured film for improving the production efficiency, and suppressing the sludge generated in the developing step.

With the related art, Korean Patent Laid-Open No. 10-2015-0017534 discloses a technique for improving the resistance to a plating solution and a time for peeling. As a technique for securing resistance to a plating solution by using a specific photopolymerizable compound, There is a problem in that a problem occurs.

It is an object of the present invention to solve the problems in the prior art described above, and it is an object of the present invention to provide a plating solution which has resistance to a developing solution to improve fine wire adhesion and resolution, Which is capable of suppressing sludge generated in a developing process and capable of exposing even a small amount of exposure energy when a laser direct exposure machine is used.

In order to accomplish the above object, a first preferred embodiment of the present invention is a photosensitive composition comprising: [A] a photopolymerization initiator; [B] an alkali developable binder polymer; and [C] a photopolymerizable compound having an ethylenic unsaturated bond in the molecule Wherein the photopolymerizable compound having an ethylenically unsaturated bond in the [C] molecule comprises a compound represented by the following general formula (1), wherein the photopolymerization initiator for the dry film photoresist To provide a resin composition.

≪ Formula 1 >

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or tert-C ₄ H _9. )

The photosensitive resin composition for a dry film photoresist of the present invention preferably contains 0.5 to 20% by weight of a photopolymerization initiator [A], 30 to 70% by weight of an alkali developing binder polymer [B], and an ethylenically unsaturated bond By weight of the photopolymerizable compound.

In the photosensitive resin composition for a dry film photoresist of the present invention, the compound represented by Formula 1 may be contained in an amount of 10 to 50% by weight based on the total weight of the photopolymerizable compound.

In the photosensitive resin composition for a dry film photoresist of the present invention, the weight average molecular weight of the alkali developable binder polymer may be 30,000 to 150,000.

In the photosensitive resin composition for a dry film photoresist of the present invention, the glass transition temperature of the alkali developable binder polymer may be 60 to 150 캜.

According to another aspect of the present invention, there is provided a dry film photoresist comprising the composition.

The photosensitive resin composition for a dry film photoresist according to the present invention has resistance to a developing solution to improve fine line adhesion and resolution, and particularly has a property of being excellent in resistance to a plating solution, and has a high peeling speed at the time of peeling, In the case of using a laser direct exposure machine, it is possible to expose even a small amount of exposure energy, so that the speed of the exposure process depends on the entire production speed, and the use of a PCB, a lead frame, a PDP, There is an advantage that productivity can be maximized in generating an image on a device or the like.

According to an embodiment of the present invention, there is provided a photopolymerization initiator comprising [A] a photopolymerization initiator, [B] an alkali developing binder polymer, and [C] a photopolymerizable compound having an ethylenic unsaturated bond in the molecule, -Phenylglycine, wherein the photopolymerizable compound having an ethylenically unsaturated bond in the [C] molecule comprises a compound represented by the following formula (1).

≪ Formula 1 >

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or tert-C ₄ H _9. )

That is, the photosensitive resin composition for a dry film photoresist of the present invention has resistance to a developing solution to improve fine line adhesion and resolution, and the cured film formed by photo-curing a photosensitive resin composition has excellent resistance to a plating solution, Is a photosensitive resin composition for a dry film photoresist capable of suppressing sludge generated in a developing process and exposing even a small amount of exposure energy in a laser direct exposure machine.

In the photosensitive resin composition of the present invention, it is preferable to include n-phenylglycine. This improves the sensitivity of the photosensitive resin composition to the laser direct exposure and improves the resistance to the developer in the developing step.

In the photosensitive resin composition of the present invention, it is preferable that the photopolymerizable compound having an ethylenically unsaturated bond in the [C] molecule includes the compound represented by the above formula (1). As a result, the sensitivity of the photosensitive resin composition to the laser direct exposure is further increased, the resistance to the developer in the developing step is further improved, and in particular, the cured film formed by photo-curing the photosensitive resin composition is excellent in resistance to the plating solution, .

The photosensitive resin composition of the present invention reacts extremely sensitively with light and can sufficiently form a reaction by using only a small amount of exposure energy to form a circuit. [C] To a photopolymerizable compound having an ethylenically unsaturated bond in a molecule, And a resist pattern can be formed during various processes of forming a resist pattern. The cured film formed by photo-curing a photosensitive resin composition has excellent resistance to a plating solution and has a short release time , It is possible to maximize the productivity in generating images by suppressing the sludge generated in the developing process.

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

[A] Photopolymerization initiator

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

In the present invention, n-phenylglycine is included as a photopolymerization initiator.

The n-phenylglycine reacts extremely sensitively to 350 to 410 nm, thereby generating sufficient photoreaction even with a small exposure energy, thereby increasing sensitivity to laser direct exposure and improving resistance to a developing solution in a developing process to form a good circuit .

If the content is less than 0.05% by weight, the reactivity of the initiator is weakened and a small amount of exposure energy (about 30 mJ / cm ² or less) is obtained. On the other hand, when the content of the n-phenylglycine is less than 0.05% , And if it is more than 2% by weight, the cross section of the post-exposure circuit has a severe history leg shape, which can not realize a desired circuit width in a circuit after the etching process, and can cause open failure in severe cases.

The photopolymerization initiator may further comprise a photopolymerization initiator usually used.

Examples of commonly used photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1- [4- (methylthio) phenyl 1-one, 2-benzyl-2-dimethylamino-1- [4-morpholinophenyl) butan- Propane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1- [4- (2-hydroxymethoxy) phenyl] -2-hydroxy- 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 3,3-dimethyl-4-methoxybenzophenone, benzophenone, 1-chloro- Methylpropane-1-one, 1- (4-dodecylphenyl) -2-hydroxypropyl-2- Methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexanoate, 4-benzoyl- 4-dimethylaminobenzoate, 2-isoamyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzylketone dimethyl acetal, benzyl ketone? -Methoxydiethyl acetal, 1- Benzoyl benzoate, bis [4-dimethylaminophenyl) ketone, 4,4'-bis (diethylamino) benzophenone, 4 , 4'-dichlorobenzophenone, benzyl, benzoin, methoxybenzoin, ethoxybenzoin, isopropoxybenzoin, n-butoxybenzoin, isobutoxybenzoin, tert- Butyl thioacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, dimethylaniline benzoate, thioxanthone compound, anthracene compound, coumarin compound, pyrazoline compound, N- Carbonyl, and the like, but glycine-based derivatives, and the like.

The content of the photopolymerization initiator is in the range of 0.5 to 20% by weight in the photosensitive resin composition. When the content of the photopolymerization initiator is within the above range, sufficient sensitivity can be obtained.

[B] Alkali developing binder polymer

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

Specific examples of the monomer include methyl acrylate, methyl methacrylate, ethyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2- The copolymerization of two or more monomers selected from linear acrylic acid polymers synthesized from methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, styrene, ≪ / RTI >

The alkali developable binder polymer of the present invention is a polymer having a weight average molecular weight of 30,000 to 150,000 and a glass transition temperature of 60 to 150 ° C in consideration of the coating property, followability, and mechanical strength of the resist itself after formation of a circuit, As a compound, 30 to 70% by weight in the photosensitive resin composition. When the content of the alkali developable binder polymer is within the above range, the effect of enhancing the fine line adhesion force after the formation of the circuit can be obtained.

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

The photopolymerizable compound having an ethylenically unsaturated bond in the molecule of the present invention has resistance to developing solution to improve the fine line adhesion and resolution, and the cured film formed by photo-curing the photosensitive resin composition has excellent resistance to the plating solution, And to suppress the sludge generated in the developing process, a compound represented by the following general formula (1) is included.

≪ Formula 1 >

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or tert-C ₄ H _9. )

The structure of R ₁ , which is an unsaturated double bond that exhibits photoreactivity, can be changed to be substituted with a hydrogen atom or a methyl group. When it is a hydrogen atom, the photoreactivity increases, and when it is a methyl group, the fine line adhesion becomes excellent.

The structure of R ₂ may be changed to be a hydrogen atom or tert-C ₄ H _9, and when it is a hydrogen atom, the resolution is excellent and when it is tert-C ₄ H ₉ , the fine line adhesion is excellent .

In the present invention, the compound represented by Formula 1 is contained in the photosensitive resin composition in an amount of 1 to 20% by weight, preferably 1.5 to 15% by weight. If the content of the compound represented by the formula (1) is less than 1% by weight, the effect is insufficient. If the content is more than 20% by weight, the development time in the development step after exposure may rapidly increase.

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 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.

[D] Other additives

The photosensitive resin composition of the present invention may further contain other additives as necessary. Examples of other additives include dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diallyl phthalate, Triethylene glycol diacetate in the glycol ester form, tetraethylene glycol diacetate; P-toluenesulfonamide in the acid amide form, benzenesulfonamide, n-butylbenzenesulfonamide; Triphenyl phosphate and the like can be used.

In the present invention, a leuco dye or a coloring material may be added to improve the handleability of the photosensitive resin composition.

Examples of the leuco dyes include tris (4-dimethylamino-2-methylphenyl) methane, tris (4-dimethylamino-2-methylphenyl) methane and fluororan dyes. Among them, when leuco crystal violet is used, the contrast is preferably good. The content of the leuco dye is preferably 0.1 to 10% by weight in the photosensitive resin composition. From the viewpoint of the appearance of contrast, the content is preferably 0.1% by weight or more, and more preferably 10% by weight or less from the viewpoint of maintaining storage stability.

Examples of the coloring material include fuchsin, phthalocyanine green, aramine base, paramagenta, crystal violet, methyl orange, nile blue 2B, victoria blue, malachite green, diamond green and basic blue 20. When the coloring material is contained, the amount added is preferably 0.001 to 1% by weight in the photosensitive resin composition. When the content is 0.001% by weight or more, there is an effect of improving the handling property. When the content is 1% by weight or less, the storage stability is maintained.

Other additives may further include heat polymerization inhibitors, dyes, discoloring agents, adhesion promoters, and the like.

In the present invention, a photosensitive resin composition for a dry film photoresist having the composition as described above is prepared, and a photosensitive resin composition for a dry film photoresist is formed on a conventional base film such as polyethylene terephthalate (PET) And then 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. It is preferable to use a laser direct exposure device including UV, visible light laser, etc. for the exposure.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

≪ Examples 1 to 4 and Comparative Examples 1 to 3 >

Photosensitive resin compositions for dry film photoresists and dry film photoresists were prepared by combining and coating according to the composition shown in Table 1 below.

First, photopolymerization initiators were dissolved in methyl ethyl ketone (MEK) as a solvent. Then, a photopolymerizable monomer and an alkali developable binder polymer were added and mixed for about 1 hour using a mechanical stirrer. Then, a photosensitive resin composition was coated on a PET film and the coated photosensitive resin composition layer was dried using a hot air oven at a drying temperature of 80 ° C, a drying time of 5 minutes, and a film thickness after drying of 38 μm. The dried film was laminated on the photosensitive resin layer using a protective film (PE).

<Experimental Example>

The exposure dose, photosensitivity, fine line adhesion, resolution, and peelability of the copper plate were measured using each dry film photoresist prepared in Examples 1 to 4 and Comparative Examples 1 to 3 as follows. Table 2 shows the results.

(1) Exposure amount

And exposed using an exposure apparatus, Pragon Ultra80.

(2) Sensitivity

The sensitivity used as a measure of reactivity was measured on a resist basis using a 21-step tablet from Stouffer Graphic Arts Equipment Co.

(3). Minimum developing time

The dry film was laminated on a copper clad laminate using a lamination equipment (Hakuto Mach 610i) at 110 ° C, lamination roll pressure of 4 kgf / cm 2, speed of 2.0 m / min, and unexposed resist was washed with Na ₂ CO ₃ 1 wt% aqueous solution at 30 DEG C and a spray pressure of 1.5 kgf / cm &lt; 2 &gt;. At this time, the minimum time of development in which no unexposed resist remained was measured.

(4) Fine wire adhesion

After the polyethylene (PE) film of the prepared photosensitive dry film resist was removed, the film was laminated to a copper plate using a heat press roller. After exposing and developing the resist using a phototool having a wiring pattern of 10 to 150 mu m divided into 5 mu m units, the adhesion of the resist was measured.

The wiring pattern of adhesion is line / space = x: 400 (unit: 탆), and the minimum value of the straight line excluding the meandering line among independent fine lines is read.

(5) Resolution

The resist was exposed and developed using a phototool having a line / space = 10: 10-150: 150 (unit: 占 퐉) wiring pattern, and the resolution of the resist was measured. In the resist pattern formed by the development after exposure, the resolution is the minimum value of the pattern in which the unexposed portion is cleanly removed.

(6) Evaluation of pollution prevention property 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 corresponding to 20 steps, and then a polyethylene terephthalate (PET) film was peeled off to form 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 plated for 15 minutes at a current of 2 A using a Hull-Cell test bath (manufactured by Precision Testers Lab.).

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

(7) Peelability

The PE film of the prepared photosensitive dry film resist was removed, laminated on a copper plate using a heat press roller, exposed to light, and developed to produce a photocured film having a size of 50 mm x 50 mm. And peeling was performed using a 3% aqueous solution of sodium hydroxide (at a temperature of 50 ° C). The evaluation of the peelability was determined as the peeling time at which the photocured film fell off the copper plate.

(8) Sludge inhibiting property

The sludge inhibition was evaluated by removing the PET and PE film of the prepared photosensitive dry film resist, dissolving 1 m ₂ in 1 liter of Na ₂ CO ₃ aqueous solution by weight and spraying for 4 hours using a circulating spray device And then left for 1 day to observe the occurrence of sludge.

A: There is no sludge at all.

B: Sludge is visible on part of the spray device.

C: Sludge is seen all over the spray device.

As shown in Table 2, it was confirmed that the fine line adhesion, resolution, and photosensitivity of the dry film photoresist prepared using the photosensitive resin composition according to the present invention were improved as compared with Comparative Example 1.

In addition, it was confirmed that the resistance and the peelability to the plating solution were remarkably superior to those of Comparative Example 2 and became absolutely small. Particularly, in the case of Comparative Example 3, it was confirmed that the sludge inhibiting property was remarkably deteriorated.

In view of this, it can be seen that when the compound of formula (1) is incorporated as a photopolymerizable compound as in the present invention, it exhibits excellent exposure value, photosensitivity, fine wire adhesion, resolution, resistance to plating solution and sludge inhibition.

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 (6)

[A] a photopolymerization initiator, [B] an alkali developing binder polymer, and [C] a photopolymerizable compound having an ethylenically unsaturated bond in the molecule, wherein the photopolymerization initiator [A] comprises n-phenyl glycine, [C] A photopolymerizable compound having an ethylenic unsaturated bond in a molecule, the compound comprising a compound represented by the following formula (1).
&Lt; Formula 1 >

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or tert-C ₄ H _9. ) The method according to claim 1,
A photopolymerizable compound having an ethylenically unsaturated bond in the [C] molecule, and 10 to 50% by weight of the photopolymerization initiator [B] Wherein the dry film photoresist is a photosensitive resin composition for a dry film photoresist. The method according to claim 1,
The photosensitive resin composition for a dry film photoresist according to claim 1, wherein the compound represented by the formula (1) is contained in an amount of 10 to 50% by weight based on the total weight of the photopolymerizable compound. The method according to claim 1,
Wherein the alkali developable binder polymer has a weight average molecular weight of 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 占 폚. A dry film photoresist comprising the composition of any one of claims 1 to 5.