JP2000155416A - Photosensitive liquid composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the photosensitive liquid composition good in coating performance by an immersion process and adapted to an etching-or plating- resistant film necessary for forming a microcircuit pattern high in density. SOLUTION: The photosensitive liquid composition is obtained by dissolving a photosensitive resin composition comprising (A) a saturated polymer having a carboxylic group and a glass transition point of 60 deg.C-150 deg.C, and (B) a photopolymerizable unsaturated compound, and (C) photopolymerization initiator, in an organic solvent. This photosensitive liquid composition has viscosity of 0.01-0.2 Pa.s at 15 deg.C-30 deg.C, and a film formed from the photosensitive liquid composition has a softening point of >=40 deg.C and this liquid composition contains the organic solvent having a boiling point of <=100 deg.C in an amount of >=50 weight %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive solution composition for forming a photosensitive film of an alkali development type used as an etching resist or a plating resist used for processing a metal foil in a laminated plate on which a metal foil is laminated. More particularly, the present invention relates to a photosensitive solution composition suitable for application by an immersion method.

[0002]

2. Description of the Related Art Conventionally, it has been known that a photosensitive resin composition is used as an etching resist or a plating resist in the fields of production of printed wiring boards, metal working and the like. The photosensitive resin composition is laminated on a support of a transparent film, and is generally called a dry film and widely used. Further, this dry film is generally of an alkali developing type. In this field, a method of printing and forming a resist pattern on a photosensitive resin composition by a screen printing method is widely and generally used. Usually, a screen printing method is used to form a rough circuit pattern,
A photo method using a dry film is used for forming a high-density and fine circuit pattern.

[0003] The formation of a fine circuit with high density on a printed wiring board will be described. A photosensitive film is formed by thermocompression bonding using a dry film on the front surface of a copper-clad laminate on which an image is to be formed. In forming a circuit pattern, an image is printed by irradiating ultraviolet rays through a photomask. afterwards,
The transparent film which is a support and serves as a protection for preventing adhesion at the time of exposure is removed, and an unexposed portion is removed with a 0.2 to 2.0% by weight aqueous sodium carbonate solution (developer) (this is referred to as development). ). Further, the portion cured by exposure is used as a resist material for an etching solution or a plating solution, and is removed by development in an unexposed portion, and the portion where the metal is exposed is etched to remove the metal. An image of a target metal is formed by drawing or plating on a plate.

When a photosensitive film is formed on a copper-clad laminate or a flexible copper-clad laminate using a dry film,
In order to enhance the adhesion between the copper foil and the photosensitive film, it is necessary to mechanically polish the copper foil surface of the copper-clad laminate or chemically polish it by soft etching to expose the copper foil surface.
At this time, deep scratches may be formed on the surface of the copper foil due to uneven handling or polishing, but it is difficult to reliably fill the scratches with the photosensitive resin composition of the dry film. For this reason, at the time of etching the copper foil, the etching solution infiltrates from a gap between the surface of the copper foil and the dry film and causes a short circuit.

Further, at the time of exposure, since the photosensitive layer and the photomask are brought into close contact with each other for the exposure, the photosensitive resin layer of the dry film and the photomask adhere to each other, thereby contaminating the photomask.
When a dry film is used, it is necessary to interpose a polyester film as a protective layer on the photosensitive layer.
Therefore, since the total thickness of the dry film is large, the difference between the dimension of the circuit pattern formed on the photomask and the dimension of the resist pattern formed by the dry film during light exposure of the dry film is caused by light scattering. Occurs.

In addition, the conventional dry film has a thickness of at least 3 in order to obtain flaw-following capability while being insufficient.
0 μm is required. 100μ resist pattern spacing
m or less, the etching rate and the plating rate decrease, and the gap between the fine circuit patterns of 100 μm or less and 100 μm or less.
The state of etching and the thickness of plating change in gaps between circuit patterns exceeding μm. In addition, the width and spacing of the conductor circuit patterns of the printed wiring are not constant, but range from several cm to several tens of μm, making it difficult to form a uniform conductor circuit.

Various alkali water-soluble UV-curable resin compositions have been disclosed, and JP-A-63-280245 discloses a styrene-maleic anhydride copolymer and a hydroxy (meth)
A photosensitive resin composition comprising an acrylate reaction product and an ethylenically unsaturated compound (reactive diluent) and a photopolymerization initiator and a monothiol or polythiol is disclosed. This requires a protective film of transparent polyester to avoid contact with the photomask during exposure.

JP-A-2-47658 discloses a copolymer of a reaction product of a styrene-maleic anhydride copolymer and an alcohol with an ethylenically unsaturated compound (reactive diluent) and (meth) acrylic acid-methyl (meth) acrylate. A photosensitive resin composition comprising a polymer and a photopolymerization initiator containing hexaarylbiimidazole and a thiol compound is disclosed. This requires a protective layer of polyvinyl alcohol.

[0009] However, these conventional techniques not only draw a fine circuit pattern, but also do not simultaneously satisfy workability and simplicity as a resist forming material when chemically etching in metal working. This is a photosensitive resin composition which has sufficient sensitivity to actinic rays such as ultraviolet rays, does not require a protective layer, and follows a scratch on a metal foil well. This required a substrate capable of drawing a resist pattern capable of withstanding chemical etching of a fine conductor circuit. A conventional dry film was able to form a resist pattern by exposing with a small amount of light.
Attempts to draw a line width of 100 μm with a spread of the line width of the exposed portion resulted in drawing a line of 120 to 140 μm. In recent years, as the wiring pattern has been miniaturized, image distortion such as an increase in line width has a problem that the accuracy of pattern formation after etching is reduced. Further, the dry film has taken measures such as reducing the thickness of the photosensitive layer, and the thickness of the photosensitive layer is now about 20 μm. However, in the case of a dry film, it is difficult to form a film having a thickness of 10 μm or less and to bond it to a copper-clad laminate. Therefore, an etching resist having a thin photosensitive layer and high image accuracy is desired.

[0010]

As an etching resist having high image accuracy, the photosensitive layer must have a thickness of 20 μm or less. An immersion method is most suitable as a method for applying the photosensitive layer, including productivity, and a photosensitive liquid suitable for the immersion method is required. Also, as a characteristic of the etching resist film, 50μ
m, can follow the scratches and steps of the copper foil. In particular, the photomask can be directly adhered without the need for a protective film or the like, and the line / space is 50/50 μm.
It is necessary to be able to form a line width of less than m

[0011]

That is, the present invention provides:
(A) having a carboxyl group and having a glass transition temperature of 60 ° C.
A photosensitive resin composition comprising a saturated polymer at ~ 150 ° C, (B) a photopolysynthetic unsaturated compound, and (C) a photoinitiator is dissolved in an organic solvent, and the temperature is from 15 to 30 ° C. At a viscosity of 0.01 to 0.2 Pa. s, a softening temperature at the time of forming a film is 40 ° C. or more, and 50% by weight or more of an organic solvent having a boiling point of 100 ° C. or less. This is a copper-clad laminate formed by applying an object and drying to form an etching resist film.

The saturated polymer having a carboxyl group as the component (A) in the present invention and having a glass transition temperature of 60 ° C. to 150 ° C. has a carboxyl equivalent of 100 to 2000.
Preferably it is 130-1000. When the glass transition temperature is lower than 60 ° C., adhesion between the photomask and the coating is likely to occur when the coating is exposed. On the other hand, when the glass transition temperature exceeds 150 ° C., the removability of the film by a stripping solution composed of an alkaline aqueous solution is reduced, and it takes a long time to remove the film from a metal foil such as a copper foil. Carboxyl equivalent is 1
When the ratio is less than 00, the film is eluted into the developing solution during development with a developing solution composed of an alkaline aqueous solution, so that the accuracy of forming a resist pattern is reduced. When the number of carboxyl groups exceeds 2,000, it is necessary to increase the concentration of sodium carbonate and sodium metasilicate as a developing solution or to increase the developing temperature. In the worst case, it may be difficult to dissolve the unexposed portions and development may not be possible.

The carboxyl equivalent is measured by titrating a sample of unit weight with, for example, 0.12 KOH to determine oxidation. Further, the weight average molecular weight of the sample is measured using GPC. From these values, the carboxyl equivalent can be determined. The glass transition temperature is measured using a thermal mechanical analyzer.

The saturated polymer as component (A) may have a hydroxyl group as a functional group. The proportion of the saturated polymer as the component (A) is preferably 60 to 80% by weight of the resin solid content contained in the photosensitive resin composition. When the content is less than 60 wt%, adhesion between the photosensitive resin film and the photomask tends to occur. When the content is 80 wt% or more, the crosslinking of the photosensitive resin composition when the film is exposed is insufficient, so that the film is eluted into the developer during the development of the film.

As the photopolymerizable unsaturated compound which is the component (B) of the present invention, an acrylate or methacrylate of a polyhydric alcohol is suitable. For example, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate,
Pentaerythritol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol di (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, amides such as methylene-bis (meth) acrylamide, (meth) acrylamide, a compound of diol (meth) acrylate and isocyanate, trialkylformal , Triallyl cyanurate and tris (2- (meth) acryloxylethyl) isocyanurate.

These photopolymerizable unsaturated compounds can be used alone or as a mixture. The content of the photopolymerizable unsaturated compound in the photosensitive resin composition of the present invention is 10% by weight or more and 40% by weight or more.
It is as follows. If the content is less than 10% by weight, the film cannot be sufficiently cured, so that the film dissolves during development. Further, from the viewpoint of increasing the softening temperature of the coating to 40 ° C. or higher,
It is desirable that the content be not more than weight%. The softening temperature of the film is 4
If the temperature is lower than 0 ° C., the film may adhere to the photomask during exposure in some cases.

As the photopolymerization initiator which is the component (C) of the present invention, any radical polymerization initiator can be used as long as it initiates the polymerization of the unsaturated compound by irradiation with actinic rays such as ultraviolet rays. For example, benzoquinone such as benzophenone, Michler's ketone, benzoin butyl ether, benzoin butyl ether, benzoin isopropyl ether, benzoin alkyl ethers such as benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-phenylacetophenone, etc. Propiophenones such as acetophenones, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, and 4-isopropyl-2-hydroxy-2-methylpropiophenone; -Ethylanthraquinone, 2
-Anthraquinones such as -t-butylanthraquinone and 2-amylanthraquinone; thioxanthones such as diethylthioxanthone, diisopropylthioxanthone and chlorothioxanthone; and other benzyl, 1-hydroxycyclohexylphenyl ketone, and 2- [4- (methylthio) phenyl] -2. -Morpholino-1-propane, p-
Isoamyl dimethylaminobenzoate and the like are preferred.

These photopolymerization initiators may be used alone or
They can be used in combination. The amount added to the photosensitive resin composition of the present invention is 0.1 to 20% by weight, more preferably 0.5 to 15% by weight.

As a solvent that can be used in the present invention, when a photosensitive resin composition is dissolved and used as a photosensitive liquid, or when a filler is mixed and dispersed to obtain a photosensitive liquid that can be easily applied,
A solvent that is easy to dry and has low toxicity is selected. For example, methanol, ethanol, propyl alcohol, isopropyl alcohol, butanol, isobutanol, ethyl acetate, amyl acetate, cyclohexyl acetate, methyl acetoacetate, dimethyl adipate, dimethyl glutamate, dimethyl succinate, cyclohexanone, methylcyclohexanone, 2-butanone, Methyl isobutyl ketone, methyl ethyl ketone, acetone, α-terpionaire, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether acetate, N, N-dimethylformamide, N, N- dimethylacetamide, dioxane, N
-Methyl-2-pyrrolidone, dimethylsulfoxide, toluene, mineral spirit and the like are selected. In particular, since the coating is performed by an immersion method, it is necessary that drying be easy, and it is preferable to use a solvent having a boiling point of 100 ° C. or less by 50% or more. As a solvent having a boiling point of 100 ° C. or lower, methanol, ethanol, ethyl acetate, methyl acetate, methyl ethyl ketone, and acetone can be used as suitable solvents. These solvents can be used alone or in a suitable mixture. If the solvent having a boiling point of 100 ° C. or less is 50% or less, dripping of the photosensitive solution occurs at the time of withdrawal when applying by the dipping method, and the thickness of the photosensitive resin film becomes nonuniform. Or development may be insufficient.

The viscosity of the photosensitive solution is 0.01 to 0.2 Pa · s
The amount of the solvent is approximately 30 to 90% by weight.
The viscosity of the photosensitive solution is preferably 0.01 to 0.2 Pa · s at a temperature of 25 ° C. for application by the dipping method. 0.01P
a. If it is less than s, the photosensitive film after drying becomes too thin, and the film may be melted during development, or a pinhole may occur in the photosensitive film. 0.2 Pa. If it is more than s, the photosensitive liquid film when applied becomes too thick,
The dripping of the photosensitive liquid is likely to occur. Further, the photosensitive film after drying becomes too thick, the resolution becomes poor, and it becomes difficult to draw a fine circuit pattern. The appropriate thickness of the photosensitive film after drying is 1 to 35 μm.

The drying temperature is about 30 to 150 ° C.
Dry for 0 minutes. Here, the drying temperature is too low, 30 ° C
When the exposure time is less than 30 minutes, not only a long drying time of 30 minutes or more is required, but also drying may not be completed completely. At the time of exposure, the mask film and the photosensitive film may stick. On the other hand, the drying temperature is too high.
If it exceeds 50 ° C, it can be dried in a short time,
The copper-clad laminate or the like serving as a base material may be subjected to thermal deformation. Furthermore, there is a possibility that the photosensitive resin composition undergoes thermal polymerization, and the developability may be deteriorated. For the drying, a hot air dryer, various dryers for far infrared rays and infrared rays can be used.

In the present invention, (A), (B),
The following components can be used as components other than (C). In order to increase the exposure sensitivity of the photosensitive resin composition,
A resin having an unsaturated bond in the molecule and soluble in an aqueous alkaline solution can be added. Such resins include styrene maleic acid resin, hydroxydiethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, polycaprolactone mono ( Methacrylate, pentaerythritol (meth) acrylate, dipentaerythritol (meth) acrylate, trimethylolpropane (meth) acrylate, neopentylglycol mono (meth) acrylate-added copolymer having an ethylenically unsaturated group and a carboxyl group Things. Alternatively, a half ester compound obtained by adding a polyvalent carboxylic anhydride to an epoxy acrylate obtained by ring-opening addition of (meth) acrylic acid to an epoxy resin is exemplified.

A filler can be used for the purpose of increasing the surface hardness by mixing and dispersing in the photosensitive resin composition of the present invention, and for adjusting the appropriate structural viscosity for adjusting the coatability. Fillers that can be used in the present invention include organic fillers and inorganic fillers, any of which may be used.As organic fillers, epoxy resins, melamine resins, urea resins,
Acrylic resin, phenol resin, polyimide resin, Teflon (registered trademark) resin, polyethylene resin, polyester resin, polyamide resin, etc. There is a filler. As the inorganic filler, fine powders of metal oxides such as alumina, silica, magnesia, and ferrite, or fine particles such as silicates such as talc, mica, kaolin, and zeolite, barium sulfate, and calcium carbonate can be used. These fillers are preferably fine particles having a maximum particle size of 2 μm or less. If the maximum particle size exceeds 2 μm, the contour of the formed image becomes uneven, and a fine or clear resist image cannot be formed. Further, if necessary, a leveling agent, an antifoaming agent, a dye, a color former, a pigment, and the like can be added. Hereinafter, an example of an embodiment of the present invention will be described with reference to examples.

[0024]

EXAMPLES Synthesis Example 1 (Saturated polymer having carboxyl group A-1) 160 g of n-butyl acrylate, 540 g of methyl methacrylate, 2-hydroxyethyl methacrylate 1
00 g and acrylic acid 200 g in the presence of peroxide in ethylene glycol monoethyl ether acetate 500
g) in 500 g of methyl ethyl ketone to obtain a saturated polymer (A-1) solution having a carboxyl group.
Glass transition temperature is 60 ° C, carboxyl equivalent is 36.
0, the resin content was 50% by weight.

Synthesis Example 2 (Saturated polymer having carboxyl group A-2) 150 g of n-butyl acrylate, 670 g of methyl methacrylate, 180 g of methacrylic acid in the presence of peroxide, 500 g of ethylene glycol monoethyl ether acetate, methyl ethyl ketone Polymerization was carried out in 500 g to obtain a saturated polymer (A-1) solution having a carboxyl group. The glass transition temperature was 80 ° C., the carboxyl equivalent was 380, and the resin content was 50% by weight.

Synthesis Example 3 (Saturated polymer having carboxyl group A-3) n-butyl acrylate 380 g, methyl methacrylate 420 g, 2-hydroxyethyl methacrylate 8
0 g, acrylic acid 120 g in the presence of peroxide, ethylene glycol monoethyl ether acetate 500 g,
Polymerization was performed in 500 g of methyl ethyl ketone to obtain a saturated polymer (A-1) solution having a carboxyl group. The glass transition temperature was 20 ° C., the carboxyl equivalent was 580, and the resin content was 50% by weight.

Example 1 Amount (parts by weight) Saturated polymer having carboxyl group (A-1) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku Co., Ltd.) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink Co., Ltd.) 0.2 Acetone 160

Example 2 Amount (parts by weight) Saturated polymer having carboxyl group (A-2) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Acetone 160

Example 3 Compounding amount (parts by weight) Saturated polymer having carboxyl group (A-1) 100 Ethylenically unsaturated compound pentaerythritol triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Photopolymerization Initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Ethanol 110

Example 4 Amount (parts by weight) Saturated polymer having carboxyl group (A-2) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku Co., Ltd.) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink Co., Ltd.) 0.2 Propylene glycol monomethyl ether acetate 80 Acetone 80

Comparative Example 1 Compounding amount (parts by weight) Saturated polymer having carboxyl group (A-3) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Acetone 160

Comparative Example 2 Compounding amount (parts by weight) Saturated polymer having carboxyl group (A-1) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Propylene glycol monoethyl ether acetate 160

Comparative Example 3 Compounding amount (parts by weight) Saturated polymer having carboxyl group (A-1) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Acetone 20

Comparative Example 4 Compounding amount (parts by weight) Saturated polymer having carboxyl group (A-2) 100 Ethylenically unsaturated compound trimethylolpropane triacrylate 17 Photopolymerization initiator (IRGACURE907 manufactured by CIBA-GEIGY) 4 Light Polymerization initiator (KAYACURE DETX manufactured by Nippon Kayaku) 1 Phthalocyanine green (CYANINE GREEN PBN-1 manufactured by Toyo Ink) 0.2 Acetone 300

The photosensitive solution compositions of the above Examples and Comparative Examples were prepared and applied to a copper-clad laminate having a size of 200 mm × 300 mm and a thickness of 1 mm by a dipping method. Coating by the immersion method is to immerse the copper-clad laminate in the photosensitive solution,
By raising at a speed of m / s. Then 10
After drying at 0 ° C. for 10 minutes, a test sample was prepared.
Next, using a photomask having a pattern with a line width of 50 μm and an interval of 50 μm, exposure was performed using a 3 kW ultra-high pressure mercury lamp so that the photosensitive film could be irradiated with a light amount of 100 mj / cm ² . The exposed photosensitive film was treated with a 1.0 wt% aqueous solution of sodium hydroxide in a developing solution whose temperature was adjusted to 30 ° C.
The film was immersed for 0 seconds for development, and the resolution of the photosensitive film was tested. In addition, the method for evaluating the characteristics of the photosensitive solution and the photosensitive solution film is shown below, and Table 1 shows the characteristics of the photosensitive solutions of Examples and Comparative Examples. Photosensitive liquid viscosity: Measured with a B-type viscometer, adjusting the liquid temperature to 25 ° C. Softening temperature of the photosensitive film: Measured with a thermal mechanical analyzer

[0036]

[Table 1] Uniformity of photosensitive coating: Thickness unevenness when applied by immersion method Film tack: Tack property between exposure mask and photosensitive film Developability: Pattern formation state of photosensitive film after exposure and development

[0037]

As described in Examples and Comparative Examples, the photosensitive solution composition according to the present invention has the following properties as shown in Table 1.
It is suitable for a coating method by an immersion method, and is effective as a film for an etching resist when forming a high-density and fine circuit pattern.

Continued on the front page F term (reference) 2H025 AB11 AB15 AC01 AD01 BC42 CA01 CA27 CA30 CB13 CB14 CB43 CB60 CC03 EA04 FA03 FA17 2H096 AA26 BA05 GA08 HA13 HA27 5E339 BE13 CC01 CD01 CE12 CE19 CF16 CF17

Claims (2)

[Claims] 1. A (A) saturated polymer having a carboxyl group and having a glass transition temperature of 60 ° C. to 150 ° C., (B) a photopolymerizable unsaturated compound, and (C) a photoinitiator. The photosensitive resin composition is dissolved in an organic solvent,
The viscosity at a temperature of 0 ° C. is 0.01 to 0.2 Pa. and a softening temperature at the time of film formation of 40 ° C. or more, and containing at least 50% by weight of the organic solvent having a boiling point of 100 ° C. or less. 2. A copper-clad laminate formed by applying the photosensitive composition of claim 1 and drying to form an etching resist film.