KR100191086B1 - Radiation curing composition - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable composition useful as a coating material, photoresist, and the like, and is an alkali developable photocurable composition having high UV sensitivity, high resolution, good adhesion, and improved chemical resistance and tenting property.

Description

Photocurable composition

The present invention relates to a photocurable composition useful as a coating material, photoresist, and the like, and more particularly, to an alkali developable photocurable composition having high UV sensitivity, high resolution, excellent adhesion, and improved chemical resistance and tenting property. .

In general, the photocurable composition is used for microfabrication of printed wiring boards, printed circuit boards, metal relief phases, and the like.

When the photocurable composition is laminated by coating or lamination on a metal surface or the like, and irradiated with ultraviolet rays, the exposed portion is cured and the unexposed portion is removed by a suitable solvent to form a desired image. Such solvents are largely divided into water-soluble and water-insoluble. Water-insoluble solvents are disadvantageous in terms of working environment, environmental pollution, and manufacturing cost, and photocurable compositions that develop with water-soluble solvents are increasing.

Typically, the photocurable composition is a polyfunctional monomer that photopolymerizes by light, a photoinitiator that induces radicals or radicals by light to cause photopolymerization, a polymeric binder that imparts mechanical strength, tentability and adhesion of the photopolymerization composition, and a dye And additives such as stabilizers, adhesion promoters and thermal polymerization inhibitors.

The photocurable composition may be used in a liquid state, or a photosensitive layer made of the photocurable composition may be laminated between the light transmissive polyester film and the protective film for workability and contamination prevention. In use, the protective film is peeled off and laminated by lamination on a dynamic layer plate and irradiated with ultraviolet rays to form an image through a development process.

The photopolymerizable polyfunctional monomer should be photopolymerized by the initiator to be resistant to the developer and to be removed from the stripper. Typically, the polyfunctional monomer uses a compound having at least one α, β-ethylenically unsaturated bond. From the viewpoint of photopolymerization, a compound having two or more acryloyl or methacryloyl groups in the molecule is preferable. For example, glycol diacrylate derivatives such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, Polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, etc., and ethylene or propylene oxide adducts of bisphenol A : N, N'-methylenebisacrylamide, N, N'-benzylidenebisacrylamide, etc.) and a compound having three or more acrylates (e.g. glycerin triacrylate, trimethylolpropane triacrylate, trimethylol ethane) Triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaarc Or the like, or a methacrylate compound corresponding to the acrylate.

Photopolymerization initiators (photoinitiators) allow the polyfunctional monomers to polymerize by ultraviolet radiation, leading to the generation of radicals by themselves with the excitation of electrons or other compounds to generate radicals. The photocuring rate of the composition is greatly influenced by the type and content of the photoinitiator. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl and the like benzophenone, 4,4 '- Alkyl benzophenones such as bis (diethylamino) benzophenone, chlorobenzophenone, 4,4'-dimethylaminobenzophenone, 4,4'-dichlorobenzophenone, 2-ethylanthraquinone and 2-t-butylanthra Anthraquinones such as quinones, 4- (dialkylamino) benzoic acid alkyl esters, 2,4,5-triarylimidazole dimers and derivatives thereof, or robin dimers, robin dimers, and leukotriphenylmethane dyes, It is used by dyes, such as a triaryl methane lyco dye, and a combination thereof.

Examples of the polymer binder include organic polymers such as acrylic polymers, styrene polymers, polyvinyl acetate, ethylene vinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, chlorinated polyethylene, chlorinated polypropylene, and vinylidene chloride polymers. , Polyester, polyamide, polyurethane, polyvinyl acetal, alkyd resin, phenol resin, epoxy resin, cellulose acetate, nitrate screen, styrene-butylene copolymer, styrene-acrylonitrile copolymer, rubber chloride, maleic anhydride Vinyl copolymers, aromatic sulfonamide formaldehyde resins, and the like.

Other additives include dyes, stabilizers, adhesion promoters and thermal polymerization inhibitors. For dyes, leuco-based dyes are mainly used and include methyl violet, malachide green, and crystal violet. Others are selected and added according to the purpose.

Alkaline developable dry film photoresist prepared from the photocurable composition is obtained by removing the protective film layer from the dry film photoresist and laminating it on a copper plate to perform ultraviolet exposure using a photo mask film or the like, and then applying an alkaline aqueous solution having an arbitrary concentration and temperature. Unexposed portions are removed to form a photoresist image. The process of forming the photoresist image by removing the unexposed portions using an alkaline aqueous solution is called development. At the time of development, the photosensitive layer of the unexposed portion is dissolved in 0.5-1.5 wt% sodium carbonate or potassium carbonate aqueous solution in the temperature range of 30 ± 5 ° C. to form an image.

There are two methods for manufacturing a printed circuit board, a plating method and an etching method. In the plating method, the plating solution and various additive chemicals must be plated to prevent the dry film resist from being eroded and peeled off during plating on the substrate. In the tenting method, the elasticity of the dry film resist film itself is required. The dry film resist acts as a resist covering the pores to protect the pores of any size that impart conductivity to the upper and lower surfaces of the substrate from the etchant. Development conditions developed by spraying with an aqueous solution of 0.5 to 1.5% by weight of sodium carbonate or potassium carbonate at a temperature of 30 ± 5 ° C., and FeCl _2, FeCl _3, CuCl _2, CuCl ₃ and persulfate in the temperature range of 50 ± 5 ° C. If the elasticity against the external stress of the dry film blocking the hole on the substrate with respect to the etching conditions in which the etching solution such as ammonia is injected, there is a problem that is broken.

Existing alkali-developing photosensitive film has a disadvantage in that the development speed is not sufficient when it is composed of the photocurable composition of the above-described components, lacking in tentability and inferior in chemical resistance.

In the present invention, the sensitivity and tentability are particularly low in the prior art, and the copolymerization monomer itself is designed as a compound having a high tentability, and by introducing a photosensitive group into the compound, sufficient sensitivity and resolution can be achieved even by reducing the content of an initiator to be put externally. I knew it was.

In the photocurable composition of the present invention, the photopolymerizable polyfunctional monomer contains a compound represented by the following structural formulas (I), (II) and (III) with 10 to 40% by weight of the entire photocurable composition. It was found that a chemical composition was obtained.

In formula (I), R is Where R ₁ is or Im) or Wherein R ₂ and R ₃ are each H, CH ₃ , or C ₂ H ₅ , and m and n are each 0-3

In Formula (II), R ₄ , R ₅ are each H or CH ₃ , and L is 6-20.

In formula (III), R ₆ , R ₇ are each H or CH ₃ , and x + y = 10-30.

Since the R portion of the structural formula (I) has a photosensitive group, the sensitivity of the photocurable composition is improved, the resolution is improved, and the rigidity and chemical resistance are excellent due to the rigidity of the structural formula (I) itself. In the present invention, even if the R portion of the compound of formula (I) does not have a photosensitive group, the tenting and chemical resistance of the photocurable composition are considerably superior to those of the general photosensitive composition due to the rigidity of the structure.

When the compound of formula (I) is used in combination with alkyl diacrylates, which are the compounds of formulas (II) and (III), the amount of photopolymerization initiator and dye can be reduced, allowing penetration into deeper UV rays, resulting in excellent resolution and clean The image can be obtained.

Structural formulas (II) and (III) impart elasticity of the resist after photopolymerization, thereby preventing the resist from brittle due to the rigidity of the compound (I), thereby helping to develop the tentability. Therefore, these addition amounts exist in an appropriate amount.

In this composition, 5-40 weight% of compound (I) with respect to a polyfunctional monomer, and 60-95 weight% of the sum total of compound (II) and compound (III) are suitable. If the amount of the compound (I) is too small, the effect is small. If the amount of the compound (I) is too large, brittle becomes brittle and the desired tentability cannot be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples. Physical property measurement method in the Example is as follows.

Measuring conditions

Lamination: Laminate roll temperature 120 ℃, roll pressure 3.0kg / ㎠, roll speed 1.5min / m on one side of 1.6mm thick copper foil laminate plate of pumice polishing of dry film photoresist made from photocurable composition Lamination was carried out using Dynachem 360 under the condition of.

☆ Developability: After leaving the dry film photoresist laminated on the copper foil laminated board for 20 minutes, it developed by developing conditions of the spray injection system of the temperature of 30 degreeC, and 1.0 weight% sodium carbonate aqueous solution. At this time, the time required until the dry film photoresist of the unexposed part on a copper foil laminated board was fully wash | cleaned by the developing solution was measured using the stopwatch. After developing under the above conditions, the resultant was dried for 10 minutes in a hot air oven at 50 ° C., and the surface state of the dry film was observed with an optical microscope at 200 magnification.

☆ Sensitivity: The dry film photoresist laminated on the copper foil laminate was subjected to UV irradiation at 20mJ and 40mJ exposure dose using a model 930SA manufactured by Collight, a 21-stage stopper tablet negative photomask, and left for 20 minutes. . Thereafter, the development was carried out under the development conditions of a spraying method of 1.0 wt% sodium carbonate aqueous solution for 30 seconds at a temperature of 30 ° C., and dried for 20 minutes in a hot air of 50 ° C., and then read the number of passes through the light.

☆ Tensability: 1.6mm thick copper foil laminate with 20 holes of 5mm diameter was developed under the same conditions as above conditions and dried under the same conditions, followed by compression of hole compression using an iron rod of 3mm diameter. All 20 holes were made. At this time, the average stress that occurs when each dry film film breaks during hole compression at a constant force and speed was recorded. Instron measurement conditions were carried out at a room temperature of 23 ° C., 50% room humidity at a loss of 1 kg and a crosshead speed of 50 mm / min.

EXAMPLE

The polymer binder was an acrylic copolymer prepared by combining acrylic acid 10, methacrylic acid 15, methyl methacrylate 60, and 2-ethylhexyl acrylate 15 in weight% relative to the polymer binder. However, this is only a method for helping understanding of the present invention, but the present invention is not limited thereto. In the present invention, in addition to the above acrylic monomers, in the range without departing from the object of the present invention, methyl acrylate, styrene, 2-phenoxy methyl acrylate, 2-phenoxy ethyl acrylate, maleic acid, maleic anhydride, vinyl acetate You may use the acrylic copolymer manufactured by this.

The overall composition of the photocurable composition is shown in Table 1. Photoinitiators and additives may be added freely without departing from the object of the present invention.

The photopolymerizable monomer simultaneously contains the polyfunctional monomer represented by the above structural formulas (I), (II) and (III).

EXAMPLES 1-7

In the composition of Table 1, the content of the photopolymerizable multifunctional monomer is added to the structure and ratio of Table 2 in a range of 30% by weight of the total photocurable composition to make a photocurable composition, which is applied to the polyester at 40 μm and protected. Lamination to a film to prepare a dry film photoresist. The prepared dry film photoresist was laminated on a copper foil laminate to evaluate sensitivity, development time, and tentability. Table 3 shows the results of the evaluation.

Comparative Examples 1-3

The content and structure of the photopolymerizable polyfunctional monomer prepared in the same manner as in Example, but added, are shown in Table 2. The photocurable composition prepared therefrom was prepared in a dry film photoresist in the same manner as in Example to measure physical properties.

Claims (1)

In a conventional photocurable composition containing a photopolymerizable polyfunctional monomer, a photopolymerization initiator, a polymer binder, and an additive, the content of the multifunctional monomer is 10 to 40 wt% based on the total composition, and the polyfunctional monomer is represented by the following structural formula ( Comprising compounds of I), (II) and (III), the content of the compound of formula (I) in the polyfunctional monomer is 5 to 40% by weight, and the compound of formula (II) and formula (III) The total amount (II + III) of the compound of 60-95% by weight of the photocurable composition, characterized in that: In formula (I), R is Where R ₁ is or Im) or (Wherein R ₂ and R ₃ are each H, CH ₃ , or C ₂ H ₅ , m and n are each 0 to 3), [In Formula (II), R ₄ , R ₅ are each H or CH ₃ , and L is 6-20. [In the formula (Ⅲ) R _6, R ₇ are each H or _{CH 3, x + y = 10} ~ 30 Im.