KR20080003948A - Four-layered dry film photoresist - Google Patents

Abstract

A dry film photoresist having a four-layer structure is provided to allow manufacture of various kinds of dry film with different optical reactivities, and to maintain physical properties while not causing such problems as fish eyes. A dry film photoresist having a four-layer structure comprises a support film, a photosensitive resin layer, a protective film, and a photoreaction controlling layer between the photosensitive resin layer and the protective film. The photoreaction controlling layer has a thickness of 0.001-3 micrometers. The photoreaction controlling layer comprises at least one component selected from photopolymerization initiators and photoreaction inhibitors.

Description

Four-layered dry film photoresist

The present invention relates to a four-layer dry film photoresist, and more particularly, it is possible to change the photoreactivity by forming a photoreaction control layer that can exhibit a variety of photoreactivity between the photosensitive resin layer and the protective film The present invention relates to a dry film photoresist having a four-layer structure that enables a plurality of dry films having different photoreactivity in one crude liquid process.

Since dry film photoresist, or photosensitive film, was developed in 1968 under the trade name `` RISTON '' by DuPont in the United States, it has been used as an important material for the current electrical and electronics industry, especially printed circuit board processing. have. Printed circuit boards are basically used for connecting parts circuits of household electronic consumer electronics parts as well as industrial electronic devices such as computers and electronic communication devices, and dry film photoresists have been used as breakthrough processing technology materials for their production. About 50% of photosensitive screen printing ink is used as dry film photoresist material for circuit formation on printed circuit board, but dry film photo is used for manufacturing printed circuit board of double-sided board and multilayer board that require high density and high reliability. Resist is essentially used.

Such dry film photoresist is usually composed of three layers: a base film, a photosensitive layer, and a cover film. Generally, the support film uses a polyester film such as polyethylene terephthalate, and its thickness is about 25 μm. Such polyester support films are used as supports during the manufacture of dry film photoresists.

The protective film serves as a protective cover that prevents damage to the resist during dust and handling, and generally a polyolefin film having a thickness of about 20 to 30 μm is used, and the polyolefin film has a sticky photosensitive layer on the mandrel without sticking to each other. By allowing it to be wound up, it plays a very important role in the manufacture, transportation and storage of photoresist in the form of a film.

When using a dry film photoresist having the above structure, the protective film is peeled off, laminated on the dynamic layer plate, and then irradiated with ultraviolet (UV) light to expose and develop the image. To form.

In other words, when the dry film photoresist 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.

The solvent is 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.

The alkali developable photosensitive resist prepared from the dry film photoresist composition removes the protective film layer from the dry film photoresist, is laminated on a copper plate, and subjected to ultraviolet exposure using a photomask film or the like, and then to an alkali having an arbitrary concentration and temperature. The unexposed portion is removed using an aqueous solution to form a photoresist phase. The process of forming the photoresist image by removing the unexposed portion using an aqueous alkali solution is called development, and during development, the photosensitive layer of the unexposed portion is dissolved in 0.5-1.5 wt% sodium carbonate or potassium carbonate aqueous solution at a temperature of 25-35 ° C. To form an image.

The manufacturing method of the printed circuit board is divided into plating method and tenting method according to the method. The plating method should have plating resistance to prevent the dry film photoresist from being eroded and peeled off during plating on the substrate for the plating solution and various additive chemicals. In the tenting method, the elasticity of the dry film photoresist film itself is required. .

On the other hand, the dry film photoresist acts as a resist covering the hole in order to protect the hole of any size which imparts conductivity to the upper and lower surfaces of the substrate from the etching solution. At this time, the development conditions developed by the spray method with 0.5 to 1.5% by weight of sodium carbonate or potassium carbonate aqueous solution at a temperature of 25 to 35 ℃, and FeCl ₂ , FeCl ₃ , CuCl ₂ , CuCl ₃ and Sufficient elasticity corresponding to the external stress of the dry film blocking the hole on a board | substrate is calculated | required with respect to the etching conditions in which etching liquid, such as ammonia sulfate, is injected.

However, the conventional alkali developable photosensitive film uses a polyolefin film such as polyethylene as a protective film, and such polyethylene film is easily removed when used as a protective film of a photosensitive resin composition due to its flexibility, chemical resistance and mold release property. In addition, the coefficient of friction with polyethylene terephthalate is large, and there are few telescopes when the product is wound. However, polyethylene has a problem in that a high molecular weight gel is produced during polymerization, and thus, even after film formation with a film, fine protrusions such as fish eyes, that is, fisheye are generated.

In order to solve this fisheye problem, International Publication No. PCT / JP01 / 07043 (2001.08.15.) Discloses a method of applying polyethylene terephthalate as a protective film instead of a polyethylene film. However, when the polyethylene terephthalate film is used as a protective film instead of the polyethylene film as described above, a phenomenon occurs that the photoreactivity of the dry film is increased, so that in order to replace the existing polyethylene film with the polyethylene terephthalate film, There is a problem that needs to be changed or a change in conditions of use is required.

In addition, since the photoreactivity is determined according to the composition of the photosensitive resin layer, a change of the resin composition is required to change the photoreactivity, and therefore, there is a problem in that the preparation of various kinds of products during the dry film preparation process.

Therefore, in the present invention, in order to solve the problems caused by changing the protective film as described above, and to solve the conventional problems such as the need to change a number of resin compositions in order to exhibit a variety of photoreactivity, a support film, a photosensitive number In a conventional dry film photoresist composed of a layer and a protective film, a four-layer dry film photoresist having a photoreaction control layer added between the photosensitive resin layer and a protective film was produced. It is possible to change the photoreactivity according to the type of components used, so that not only the dry film with different photoreactivity can be manufactured in one crude liquid process but also the protective film instead of the polyethylene protective film having the fisheye problem. To apply polyethylene terephthalate protective film Solving the problem that the photoreactivity of the dun dry film is raised to exhibit the same photoreactivity, it was found that it is possible to manufacture a dry film product of the same physical properties to reach the present invention.

Therefore, an object of the present invention is not only possible to manufacture a variety of dry film with different photoreactivity in one bath liquid process, but also to maintain the same physical properties without causing problems, such as fisheye when using PET as a protective film It is to provide a dry film photoresist of a layer structure.

Four-layer dry film photoresist of the present invention for achieving the above object is a dry film photoresist consisting of a support film, a photosensitive resin layer, a protective film, the photoreaction between the photosensitive resin layer and the protective film It is characterized by including a layer.

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

The present invention further includes a photoreaction control layer between the photosensitive resin layer and the protective film in a dry film photoresist having a three-layer structure containing a support film, a photosensitive resin layer, and a protective film.

The support film of the present invention is not particularly limited as long as it is used as a support film of a general dry film photoresist. For example, a homopolymer such as polyethylene terephthalate, polypropylene, nylon, polyethylene, polyvinyl chloride or the like may be used. It is usually selected from the films obtained from other polymers containing 50% or more, and the thickness thereof is usually preferably 5 to 100 µm, but is not limited thereto.

In addition, the photosensitive resin layer contains a binder polymer, a photopolymerizable oligomer, a photopolymerization initiator, and other additives such as colorants and pigments, and the like, although each of the above components is not particularly limited.

Binder Polymer

The binder polymer of the present invention is an alkali developable binder polymer, and it is preferable to further use a copolymer of (meth) acrylic acid and (meth) acrylic acid ester or a styrene polymer. Specifically, at least two selected from Copolymerized acrylic acid polymer obtained through copolymerization of monomers; Methyl acrylate, methyl methacrylate, ethyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid, methacrylic acid, 2-hydroxy ethyl acrylate, 2-hydroxy ethyl methacrylate, Linear acrylate polymers synthesized from 2-hydroxy propyl acrylate, 2-hydroxy propyl methacrylate, acrylamide, methacrylate, styrene, α-methyl styrene, and the like. It is preferable that the weight average molecular weight is 30,000 to 150,000, and the glass transition temperature is in the range of 20 to 150 ° C. in consideration of coating property, followability, and mechanical strength of the resist itself after circuit formation.

The content of the alkali developable binder polymer of the present invention is preferably 20 to 80% by weight in the photosensitive resin layer composition, but is not limited thereto.

<Photopolymerizable oligomer>

The photopolymerizable oligomer preferably includes monomers having at least two ethylene groups at the ends thereof, for example, 1,6-hexanediol (meth) acrylate, 1,4-cyclohexanediol- (meth) acrylate, Polypropylene glycol (meth) acrylate, polyethylene glycol- (meth) acrylate, 2-di- (p-hydroxyphenyl) -propane-di- (meth) acrylate, glycerol tri (meth) acrylate, trimethylol Propane tri- (meth) acrylate, polyoxypropyl trimethylol tri- (meth) acrylate, polyethylene (propylene) -di (meth) acrylate containing bisphenol-A groups, and And polyfunctional (meth) acrylates containing urethane groups.

<Photoinitiator>

In the photosensitive resin composition, the photoinitiator is a material that initiates a chain reaction of the photopolymerizable monomer by UV and other radiation, and is a compound that plays an important role in curing the dry film resist.

As a compound which can be used as such a photoinitiator, Anthraquinone derivatives, such as 2 methyl anthraquinone and 2 ethyl anthraquinone; And benzoin derivatives such as benzoin methyl ether, benzophenone, phenanthrene quinone, and 4,4'-bis (dimethylamino) benzophenone.

In addition to 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino Propane-1-one, 2-benzyl-2-dimethylamino-1- [4-morpholinophenyl] butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, 1- [4- (2-hydroxymethoxy) phenyl] -2-hydroxy-2-methylpropan-1-one, 2,4-diethylthione Oxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 3,3-dimethyl-4-methoxybenzophenone, benzophenone, 1-chloro-4-propoxycyxanthone, 1- ( 4-isopropylphenyl) 2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2hydohydroxy-2-methylpropan-1-one, 4-benzoyl-4 ' -Methyldimethylsulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-iso Wheat 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzylketone dimethylacetal, benzylketone β-methoxy diethylacetal, 1-phenyl-1,2-propyldioxime-o, o'- (2-carbonyl) ethoxyether, methyl o-benzoylbenzoate, 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-tert -Butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methyl thioxanthone, 2-isopropyl thioxanthone, dibenzosuberon, α, α-dichloro-4-phenoxy Compounds selected from acetophenone and pentyl 4-dimethylaminobenzoate can be used as the photopolymerization initiator.

Although the content of the photoinitiator of this invention is 2-10 weight% in a photosensitive resin layer composition, it is not limited to this.

Solvents and Other Additives

As a solvent of the photosensitive resin composition of this invention, although the thing chosen from methyl ethyl ketone (MEK), methanol, THF, toluene, and acetone is generally used, it is not specifically limited to the said solvent.

Moreover, the plasticizer which the photosensitive resin composition of this invention is added normally other than said composition. Additives such as stabilizers, leveling agents, color aids, coloring agents and the like may be further included, of course, the specific components and contents thereof are not particularly limited and are usually added levels.

The present invention includes a photoreaction control layer prepared by adding various components. Specifically, the photopolymerization initiators may be reacted to improve the photoreactivity of the dry film, and to reduce the photoreactivity of the dry film. Add an inhibitor etc.

The photopolymerization initiators added to increase the photoreactivity of the dry film include benzoin and derivatives thereof such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; benzyl; Benzophenones and derivatives thereof such as benzophenone, 4,4'-bis (diethylamino) benzophenone, chlorobenzophenone, 4,4'-dimethylaminobenzophenone and 4,4'-dichlorobenzophenone; Anthraquinones such as 2-ethylanthraquinone and 2-t-butylanthraquinone; 4- (dialkylamino) benzoic acid alkyl ester; 2,4,5-triarylimidazole dimers and derivatives thereof, and the like.

In addition, photoreaction inhibitors that may be included to reduce the photoreactivity are applied to a common antioxidant, for example, selected from phosphite derivatives, in this patent specifically phenyl diisodecyl phosphite (Phenyl Diisodecyl Phosphite) Although it is preferable to use, it is not limited to this.

The photoreaction control layer of the present invention is preferably used by dissolving at least one component selected from the above-described photopolymerization initiator or photoreaction inhibitor in 0.3 to 50% by weight in a solvent selected from methyl ethyl ketone, acetone, methanol, ethanol and THF. Do.

 The coating method of the photoreaction control layer is not particularly limited, and the thickness at the time of coating on the photosensitive resin layer is appropriately 0.001 to 3㎛ level, preferably 0.01 to 1㎛ level. The layer having a thickness of less than 0.001 μm is difficult to manufacture and difficult to secure a uniform photoreaction control function, and when it exceeds 3 μm, the increase in the photoreaction effect is insufficient and the manufacturing cost increases.

In addition, as the protective film of the present invention, all of an olefin-based film such as polyethylene and a polyester-based film such as polyethylene terephthalate may be used, but are not limited thereto.

This is possible because the present invention further includes a photoreaction control layer as described above, which solves the fish-eye problem that occurs when the polyethylene film is used as a protective film in the prior art. In addition, even if a polyethylene terephthalate film is used as a protective film, the photoreactivity can be easily adjusted due to the photoreaction control layer according to the present invention, so that the photoreactivity of the dry film can be adjusted. Problems such as changing the composition of the resin composition or changing the use conditions do not occur.

Although the thickness of the protective film of this invention as mentioned above is not specifically limited, It is preferable that it is 1-100 micrometers normally.

In the dry film photoresist of the present invention, the photosensitive resin composition is coated on the support film by a conventional coating method well known in the art to form a photosensitive resin layer, and then the photoreaction control which can control photoreactivity as described above. The layer is applied and finally a protective film is applied.

In addition, the process of forming the photosensitive resin layer was performed according to a conventional dry film photoresist manufacturing process, it is not particularly limited in the present invention.

Lamination in the present embodiment was used Hakuto Mach610i equipment, lamination conditions were carried out under the conditions of temperature 110 ℃, lamination roll pressure 4kgf / cm 2, speed 2.0m / min.

The reactivity of the dry film was that after laminating the dry film on the CCL, the Stouffer Step Tablet was placed on the surface of the dry film, followed by an exposure process. The exposure equipment in this example used Perkin-ElmerTM OB7120.

After leaving the exposure process for 15 minutes, the development of the dry film (break point = 50%) was performed by using a developer to determine the number of remaining dry film stages to evaluate the reactivity of the dry film. At this time, the developing conditions used were evaluated under conditions of a developer concentration Na ₂ CO ₃ 1% by weight aqueous solution, temperature 30 ℃, spray pressure 1.5kgf / ㎠, 50% breaking point.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by Examples.

Examples 1-4 and Comparative Examples 1-2

As a support film, a photosensitive resin composition having a composition as shown in Table 1 was applied on a polyethylene terephthalate film having a thickness of 19 μm to form a photosensitive resin layer.

ingredient Content (parts by weight) menstruum Methyl ethyl ketone 20 Photoinitiator Benzophenone 4,4 '-(bisdiethylamino) benzophenone 3.0 3.0 additive Luco Crystal Violet Toluenesulfonic Acid Monohydrate Diamond Green GH 0.4 0.4 0.2 Photopolymerizable oligomer BPE-500 (Shin-nakamura) M281 (Miwon Corporation) A-TMPT-3EO 6 6 6 Binder polymer KOLON BP-1 (50% solids) 55

In Examples 1 to 4, the photosensitive resin layer was formed, and then the photoreaction control layer components of the following Table 2 were dissolved in a methyl ethyl ketone (MEK) solvent, and then applied to a thickness of about 0.5 μm to form a photoreaction control layer. To form, and finally to form a protective film of the material shown in Table 2 to prepare a dry film photoresist.

In Comparative Examples 1 and 2, the photosensitive resin layer was formed, and then, only the protective film was formed without forming a photoreactive control layer to prepare a dry film photoresist.

Protective film material Photoreaction Control Layer Comparative Example 1 Polyethylene - Comparative Example 2 Polyethylene terephthalate - Example 1 Polyethylene Benzophenone Example 2 Polyethylene terephthalate Benzophenone Example 3 Polyethylene Phenyl diisodecyl phosphite Example 4 Polyethylene terephthalate Phenyl diisodecyl phosphite

Photoreactivity according to the exposure amount of the obtained dry film photoresist is shown in Table 3 below. The result was expressed by the stopper step 21 stage, the larger the value means that the photoreactivity is greater.

As can be seen from the results of Table 3, Example 1 and Example 3 using polyethylene as a protective film, and Example 2 and Example 4 using polyethylene terephthalate as a protective film material are all on the same photosensitive resin composition. It is possible to manufacture a dry film photoresist having a different photoreactivity, and the photoreactivity can be adjusted by adding a photoreaction control layer as in the present invention, in particular, photoreactivity according to the protective film material as in Comparative Example 1 and Comparative Example 2 Do. In addition, when the conventional polyethylene terephthalate is applied as a protective film, the problem of increasing the photoreactivity did not occur when the photoreaction control layer was formed as in the present invention. In addition, the fish eye problem generated when the polyethylene film is used as a protective film can be solved when the photoreaction control layer is included as in the present invention. In addition, as a result of comparing the physical properties in the same eight-step step using the stow step step 21, it can be seen that all have the same physical properties at the significant difference level.

Examples 5-8

In the following examples, the photosensitive resin layer was formed using the same photosensitive resin composition as in Example 1, and then photoreactivity was evaluated according to the thickness change of the photoreaction control layer as shown in Table 4 below.

Protective film material Photoreaction Control Layer Components Thickness (㎛) Comparative Example 1 Polyethylene - - Example 5 Polyethylene Benzophenone 0.0005 Example 6 Polyethylene Benzophenone 0.1 Example 7 Polyethylene Benzophenone 3.0 Example 8 Polyethylene Benzophenone 3.5

Photoreactivity according to the exposure amount of the dry film prepared according to Examples 5 to 8 is shown in Table 5 below.

As shown in the results of Table 5, it can be seen that there is a sensitivity increase effect as the thickness of the photoreaction control layer increases, the effect is insignificant when the thickness is less than 0.001㎛ as in Example 5, as in Example 8 If it exceeds 3㎛ there is no effect of increasing the photoreactivity. In addition, as a result of comparing the physical properties in the same eight-step step using the stow step step 21, it can be seen that all have the same physical properties at the significant difference level.

As described in detail above, the dry film photoresist having a four-layer structure in which a dry film photoresist having a three-layer structure consisting of a support film, a photosensitive resin layer, and a protective film is further included on the photosensitive resin layer is used. Regardless of the kind of protective film to be used, the same photosensitive resin composition may be used to produce a dry film photoresist having various photoreaction characteristics.

Claims (6)

In a dry film photoresist consisting of a support film, a photosensitive resin layer, and a protective film, Dry film photoresist having a four-layer structure formed a photoreaction control layer between the photosensitive resin layer and the protective film. The dry film photoresist of claim 1, wherein the photoreaction control layer is formed to a thickness of 0.001 to 3 μm. The dry film photoresist of claim 1, wherein the photoreaction control layer is formed to a thickness of 0.1 to 1 μm. The dry film photoresist of claim 1, wherein the photoreaction control layer comprises at least one component selected from a photopolymerization initiator or a photoreaction inhibitor. The photopolymerization initiator according to claim 4, wherein the photopolymerization initiator is benzoin and its derivatives, benzyl, benzophenone and its derivatives, anthraquinones, 4- (dialkylamino) benzoic acid alkyl esters, or 2,4,5-triarylimide. Dry film photoresist, characterized in that at least one selected from sol dimers and derivatives thereof. The dry film photoresist of claim 4, wherein the photoreaction inhibitor is diisodecyl phosphite.