JPH06202322A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To enable development with a weak alkali soln. and to improve adhesion property and alkali resistance and mechanical strength in a polymerized part by incorporating a specified copolymer or mixture, crosslinking agent, and photopolymn. initiator. CONSTITUTION:This compsn. contains a hydroxystyrene polymer and a copolymer of hydroxystyrene, styrene, methylmethacrylate, butylmethacrylate, or hydroxyethylmethacrylate or mixture of these by 30-60wt.% of the whole solid content, a crosslinking agent having two or more (meth)acrylate groups in the molecular chain by 30-60wt.% of the whole solid content, and a photopolymn. initiator by l-15wt.% of the whole solid content. To prepare this photopolymerizable compsn., these components are only mixed. When the compsn. is to be used, the photopolymerizable compsn. is dissolved in an org. solvent such as methylethylketone, acetone, and methylcellusolve, and for example, applied on a substrate and dried to form a photosensitive layer which can be used as a dry film resist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable composition, and more particularly to a photopolymerizable composition that can be used for film production, photoresists and the like.

[0002]

2. Description of the Related Art Currently, photoresist materials are widely used as materials for manufacturing printed circuit boards. Liquid photoresist, dry film resist, L
Electron beam resists, X-ray resists, and the like used for manufacturing ultrafine structures such as SI are known. Properties commonly required for these photoresist materials include high sensitivity, high resolution, high etching resistance, high adhesion to substrates, and high dimensional accuracy after development. .

There are two types of photoresists, a negative type in which the irradiated portion is insoluble in the developing solution by light irradiation, and a positive type in which the exposed area is solubilized. The negative type is superior to the positive type in sensitivity, adhesion to a substrate, chemical resistance, etc., and the positive type is superior in resolution and dry etching resistance.

On the other hand, photoresists are also distinguished by the type of developer. For example, a solvent development type using an organic halogen solvent represented by 1,1,1-trichloroethane,
It is roughly classified into two types, an alkali developing type using a weak alkaline aqueous solution represented by an aqueous sodium carbonate solution. At the time when the use of photoresists began, solvent-developing type was the mainstream, but nowadays, solvent-developing type photoresists are rarely used due to problems of working environment and natural environment, and demand for alkali-developing type photoresists is increasing. It has increased. However, when it is necessary to immerse the polymerized photoresist in an alkaline solution in the work process, the photopolymerizable portion of the alkali-developable resist is relatively weak to alkali, so that peeling or dissolution from the substrate may occur. The solvent developing type is still used for such a part, and it is necessary to change it to the alkali developing type in the environment.

In recent years, as products are becoming smaller, many parts having a fine structure are used in products. It is difficult to construct this fine structure down to the micron level by die molding and the cost is very high. Therefore, by applying a photoresist to such a field, it becomes possible to construct a fine structure at a low cost with simple operation. However, the conventional photoresist is a process material that is eventually removed from the product, so the mechanical strength and other properties required for permanent materials are not added, and in reality the durability is insufficient. is there.

[0006]

The object of the present invention is to develop using a weak alkaline aqueous solution and to have excellent adhesiveness,
Another object of the present invention is to provide a photopolymerizable composition in which the polymerized portion after curing has alkali resistance and also has excellent mechanical strength.

[0007]

According to the present invention, a hydroxystyrene polymer, a copolymer of hydroxystyrene and styrene, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate or a mixture thereof (hereinafter referred to as component A) ) In the total solid content of 30 to 60
% By weight, and 30-60% by weight based on the total solid content of a crosslinking agent having two or more (meth) acrylic acid ester groups in the molecular chain.
And a photopolymerization initiator in an amount of 1 to 15% by weight based on the total solid content.

The present invention will be described in more detail below.

A hydroxystyrene polymer used as the component A which is an essential component in the photopolymerizable composition of the present invention,
The weight average molecular weight of the copolymer of hydroxystyrene and styrene, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, or a mixture thereof is a value converted into polystyrene by GPC (gel permeation chromatography), preferably 50.
The range is from 00 to 50,000. The weight average molecular weight is 5
When it is less than 000, the mechanical strength after molding and curing is lowered to deteriorate the durability, and when it exceeds 50,000, the synthesis becomes difficult, which is not preferable.

The copolymer of the above-mentioned component A is random,
It may be either a block polymer or a graft polymer, and the mixing ratio of the hydroxystyrene unit to the styrene, methylmethacrylate, butylmethacrylate, hydroxyethylmethacrylate unit or a mixed unit thereof is 1: 0.5 to 2 in molar ratio. Is preferred. To prepare the hydroxystyrene polymer and the copolymer of the hydroxystyrene and styrene, methylmethacrylate, butylmethacrylate, or hydroxyethylmethacrylate, heat polymerization is performed in the presence of a radical polymerization catalyst such as an organic peroxide. It can be obtained by known radical polymerization such as.

The content of the component A in the photopolymerizable composition of the present invention is 30 to 60% by weight based on the total solid content,
It is preferably in the range of 45 to 55% by weight. If the content is less than 30% by weight, the moldability of the cured product will decrease,
If the tackiness increases and deteriorates, and if it exceeds 60% by weight, the cured product becomes hard and brittle, so it is necessary to set it within the above range.

Examples of the cross-linking agent having two or more (meth) acrylic acid ester groups in the molecular chain used as an essential component in the photopolymerizable composition of the present invention include, for example, hexanediol di (meth) acrylate and neopentyl glycol. Di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, 1,
Acrylic acid adduct of diglycidyl ether of 6-hexanediol, di (meth) acrylate of acetalization product of hydroxypivalaldehyde and trimethylolpropane, 2,2-bis [4- (acryloyloxydiethoxy) phenyl] methane 2,2-bis [4- (acryloyloxydiethoxy) phenyl] propane, hydrogenated bisphenol A ethylene oxide adduct di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, trimethylolpropane tri (Meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane propylene oxide adduct tri (meth) acrylate, glycerin propylene oxide adduct tri (meth) acrylate, dipentaerythritol hex Mixture of (meth) acrylate / penta (meth) acrylate, lower fatty acid of dipentaerythritol and ester of acrylic acid, tris (acryloyloxyethyl) isocyanate, caprolactone adduct of dipentaerythritol (meth) acrylate, dipentapropionate Examples thereof include erythritol penta (meth) acrylate and a caprolactone adduct of hydroxypivalic acid neopentyl glycol di (meth) acrylate. The content of the cross-linking agent is 30 to 60% by weight, preferably 35 to 40% by weight, based on the total solid content of the composition. When the content is less than 30% by weight, the curability is deteriorated, and the tackiness is further increased and deteriorated. When the content exceeds 60% by weight, the cured product is hard,
Since it becomes brittle, it must be within the above range.

Examples of the photopolymerization initiator used as an essential component in the photopolymerizable composition of the present invention include benzoin isopropyl ether, benzoin ethyl ether, benzophenone, benzophenone methyl ether, 2-ethylanthraquinone, 2,4-dimethylthioxanthone, 2,2-dimethoxy-2-phenylacetophenone, p-tert-butyltrichloroacetophenone,
Examples thereof include hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one. The content ratio of the photopolymerization initiator is 1 to 15% by weight, preferably 5% by weight based on the total solid content of the composition.
~ 11% by weight. If the content is less than 1% by weight, the desired photopolymerization does not proceed, and if it exceeds 15% by weight, the strength of the cured product decreases, so the content must be within the above range.

In the photopolymerizable composition of the present invention, in addition to the above essential components, a polymerization inhibitor that does not interfere with photopolymerization of hydroquinone and its derivatives, a coloring agent that does not interfere with photopolymerization such as oil-soluble dyes and pigments, and the like. Additives can be included as needed.

To prepare the photopolymerizable composition of the present invention,
It suffices to mix the above-mentioned components, and in use,
The photopolymerizable composition is dissolved in an organic solvent such as methyl ethyl ketone, acetone, or methyl cellosolve, and the photosensitive layer is formed by, for example, coating and drying on a substrate, which can be used as a dry film resist or a photosensitive substrate. .
When an image is formed, the formed photosensitive layer is irradiated with light from a xenon lamp, an ultra-high pressure mercury lamp, a halogen lamp or the like through a photomask to cause photopolymerization and then development with a weak alkaline solution. By doing so, a desired image can be obtained. If necessary, a cured film of an image having excellent durability can be obtained by subsequently performing heat treatment and then curing.

[0016]

The photopolymerizable composition of the present invention has high adhesiveness to stainless steel, glass substrates and the like, can be developed with a weak alkaline aqueous solution, and has good image forming property. Further, since it has excellent durability and alkali resistance by heat curing, it is extremely useful as a material for a photoresist, a product requiring a fine structure, a protective film, and the like.

[0017]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0018]

Example 1 11 g of a polymer having a weight average molecular weight of 9300, which is 1: 1 (molar ratio) of parahydroxystyrene and methyl methacrylate as the component A, and caprolactone addition of tricyclodecane dimethanol diacrylate dipentaerythritol as a crosslinking agent. Acrylate 7g, photopolymerization initiator 2,2-dimethoxy-2-phenylacetophenone 2g, solvent methyl ethyl ketone 20
A resist solution was prepared using g.

The prepared solution was uniformly applied to a polyethylene terephthalate film having a thickness of 30 μm using a bar coater and dried in a dryer at 120 ° C. for 10 minutes.
The thickness of the photopolymerizable layer after drying was 50 μm. A 35 μm polyethylene film was laminated on the surface of the photopolymerizable layer on which no polyethylene terephthalate film was laminated to obtain a laminated film.

Next, a photopolymerizable layer of the film obtained by peeling the polyethylene film of the laminated film was laminated at 100 ° C. on a stainless substrate having a thickness of 80 μm, the surface of which was mirror-finished and ultrasonically treated in acetone for cleaning. did.
Through a patterned mask film having a line / space of 40 μm on the substrate laminated with the photopolymerizable layer,
Ultra-high pressure mercury lamp (Oak, product name "UV-330AP
I ") exposed the photopolymerizable layer at 500 mJ / cm ² . Subsequently, after peeling off the polyethylene terephthalate support film, it was sprayed with a 1.5% tetramethylammonium hydride aqueous solution at 30 ° C. for 1 minute at a spray pressure of 0.5 k.
Spray development was carried out at g / cm ² to remove the unreacted portion, and a good cured image was obtained. Then, it was heated and cured at 150 ° C. for 1 hour to obtain a final cured product.

The dry film photoresist and the cured product thereof obtained in the above steps were evaluated as follows. The results are shown in Table 2.

When no tackiness is felt when the polyethylene film for tackiness protection is peeled off, ○, when there is some tackiness but cannot be laminated to the substrate without heating and pressurization, when attached to the stainless steel substrate, The case where the film was not peeled off even if it was pasted without applying heat and pressure was marked with Δ, and the case where the resist adhered to the polyethylene film was marked with x.

After the adhesive lamination, when the polyethylene terephthalate film is peeled off by exposing the entire surface without cutting the pattern, when the resist does not adhere to the polyethylene terephthalate film at all, ○, it does not adhere to the polyethylene terephthalate film, but is slightly peeled from the substrate The case was evaluated as Δ, and the case where the film was left on the polyethylene terephthalate film without being adhered to the substrate was evaluated as ×.

Development Time The time at which the unexposed portion completely disappeared by the developer was measured.

When the width of the pattern exposed and developed using a line & space pattern mask having a pattern shape of 40 μm is 40 μm ± 2 μm, it is ○, and when it is more or less than that, there is a gap between images, and most of them are Δ. The case where there was no gap between the images was marked with x.

Sensitivity The product was exposed and developed at 100 mJ / cm ² using a trade name “Photographic step tablet no. 2” (manufactured by Kodak Co.), and the sensitivity was examined by the number of remaining step tablets after development.

Immersion test The resist after exposure, development and heat treatment has a pH of 10
An immersion test was performed at 70 ° C. for 6 days in the monoethanolamine aqueous solution adjusted to. After this test, no peeling of the resist was observed, ◯, swelling that was not peeled but swelling was evaluated as Δ, and peeled and dissolved was evaluated as x.

Volume shrinkage A resist was laminated on a nickel foil having a thickness of 20 μm, a length of 3 cm and a width of 8 mm, and exposed at 500 mJ / cm ² , and 1
The size of the sled after heating at 50 ° C. for 1 hour and cooling for 1 hour was examined.

[0029]

Examples 2 to 9 Dry film photoresists and cured products thereof were prepared in the same manner as in Example 1 with the compositions shown in Table 1, and each evaluation was performed. The evaluation results are shown in Table 2.

[0030]

Comparative Examples 1 and 2 As Comparative Example 1, 10 g of poly (n-butyl methacrylate / ethyl methacrylate) (6/4) (Mw = 25000) was used as the polymer component, 12 g of glycidyl methacrylate was used as the crosslinking agent, and 2 was used as the photopolymerization initiator. ，
Using a photopolymerizable composition containing 2 g of 2-dimethoxy-2-phenylacetophenone, a film thickness of 5 was obtained according to Example 1.
A dry film having a thickness of 0 μm was produced and evaluated in the same manner as in Example 1. As Comparative Example 2, 10 g of a 1: 1 (molar ratio) copolymer of methacrylic acid and methyl acrylate (weight average molecular weight 15,000) was used as a polymer component, 8 g of trimethylolpropane triacrylate was used as a cross-linking agent, and 2 g of a photopolymerization initiator. The photopolymerizable composition containing 2 g of 2-dimethoxy-2-phenylacetophenone was evaluated in the same manner as in Example 1. The results are shown in Table 2. At this time, in Comparative Example 1, only solvent development of 1,1,1-trichloroethane or the like was possible, and alkali development was not possible. Further, in Comparative Example 2, even when the film was formed and dried, the film was inflexible and cracked, and it was difficult to laminate it on the substrate. Even after exposure and development, there was no gap between pattern images.

[0031]

[Table 1]

[0032]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI Technical indication G03F 7/028 7/033 H01L 21/027 H05K 3/28 D 7511-4E

Claims (1)

[Claims] 1. A hydroxystyrene polymer, a copolymer of hydroxystyrene and styrene, methylmethacrylate, butylmethacrylate, hydroxyethylmethacrylate or a mixture thereof in an amount of 30 to 60% by weight based on the total solid content in a molecular chain. A photopolymerizable composition containing 30 to 60% by weight of a crosslinking agent having two or more (meth) acrylic acid ester groups in the total solid content and 1 to 15% by weight of a photopolymerization initiator in the total solid content. .