JPH0728238A - Photosensitive resin composition and production of photosensitive element and resist pattern using the same - Google Patents

Abstract

PURPOSE:To provide a photosensitive resin compsn. ensuring improved strength of a tinting film and improved property of following the ruggedness of a substrate. CONSTITUTION:This photosensitive resin compsn. contains a graft polymer having acid value of 20-300 obtd. by copolymerizing acrylic acid and/or methacrylic acid and a macromonomer having one polymerizable unsatd. group at one terminal of an alkyl acrylate or alkyl methacrylate polymer as essential components, a monomer having two or more photo-polymerizable unsatd. groups in each molecule and a photopolymn. initiator. A photosensitive element and a resist pattern are produced using this photosensitive resin compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition used for printed wiring boards and the like, a photosensitive element using the same and a method for producing a resist pattern.

[0002]

2. Description of the Related Art When manufacturing a printed wiring board,
First, a film of a photocurable photosensitive resin composition is usually formed on a substrate, and then an actinic ray is imagewise irradiated to develop and remove an unexposed portion to form a resist pattern. In this step, various methods are adopted for forming the film of the photosensitive resin composition. For example, by a method such as dip coating, roll coating, or curtain coating, the photosensitive resin composition solution (coating liquid) is directly applied to the substrate, and the solvent is dried to obtain the photosensitive resin composition on the support. A method for laminating a laminated photosensitive element (photosensitive film) on a substrate,
Furthermore, a method is known in which a substrate is immersed in a bath in which a photosensitive resin composition is dispersed in water, and a film is formed using a method called electrodeposition coating.

Of these methods, the method of laminating a photosensitive film is currently used as a mainstream method because a film of a photosensitive resin composition having a uniform thickness can be easily formed. After forming the resist pattern, in the case of the tenting method, the printed wiring board is subjected to etching and resist stripping steps, and in the case of the plating method, the printed wiring board is subjected to solder plating, resist stripping and etching steps. It has gained.

Therefore, the characteristics required for the photosensitive resin composition are not only good photosensitivity characteristics such as photosensitivity, but also adhesion to metal, followability to irregularities on the substrate surface, etching solution and plating solution. There are various factors such as chemical resistance to chemicals such as the above, resist peeling property, and in the case of the tenting method, strength of the tenting film.

Above all, the ability to follow irregularities on the surface of the substrate and the strength of the tenting film are important characteristics. However, these two characteristics are difficult to be compatible with the conventional material technology, and there is a problem that if one of the characteristics is increased, the other characteristic is deteriorated.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, and is a photosensitive resin composition which is excellent not only in the conformability to the irregularities on the substrate surface and the strength of the tenting film, but also in the photosensitive characteristics. An object, a photosensitive element using the same, and a method for producing a resist pattern are provided.

[0007]

The present invention solves the above problems by using a graft polymer obtained by copolymerizing a special macromonomer.

That is, the present invention provides an acid obtained by copolymerizing (a) acrylic acid and / or methacrylic acid with a macromonomer having one polymerizable unsaturated group at one end of alkyl acrylate or alkyl methacrylate as an essential component. A photosensitive resin composition containing a graft polymer having a valence of 20 to 300, (b) a monomer having two or more photopolymerizable unsaturated groups in the molecule, and (c) a photoinitiator, and photosensitivity using the same. The present invention relates to a method for manufacturing an element and a resist pattern.

The present invention will be described in detail below. The polymer as the component (a) is an acid value obtained by copolymerizing acrylic acid and / or methacrylic acid and a macromonomer having one polymerizable unsaturated group at one end of polyalkyl acrylate or polyalkyl methacrylate as an essential component. 20 ~
300 graft polymer. Acrylic acid and methacrylic acid may be used alone or in combination. The amount used is appropriately used so that the acid value of the polymer is in the range of 20 to 300. When the acid value of the polymer is less than 20, the developability of the photosensitive resin composition with an aqueous alkali solution is lowered, and when the acid value is more than 300, the developing solution resistance of the resist after photocuring is lowered.

On the other hand, the macromonomer having one polymerizable unsaturated group at one end of a polymer of alkyl acrylate or alkyl methacrylate is, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-dodecyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, n
-One polymerizable unsaturated group such as an acryloyl group or a methacryloyl group at one end of a polymer of an alkyl acrylate or alkyl methacrylate having an alkyl group (preferably having a carbon number of 12 or less) such as octyl methacrylate or n-dodecyl methacrylate. It is a polymer having.
In particular, a macromonomer having a methacryl group at one end of a polymer such as methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate is suitable. The macromonomers may be used alone or in combination of two or more.

The number average molecular weight of the macromonomer used in the present invention is preferably in the range of 1,500 to 200,000, more preferably in the range of 3,000 to 50,000.
When the number average molecular weight of the macromonomer is less than 1,500,
The effect of forming a graft polymer using a macromonomer tends to be insufficient, while the molecular weight is 200,00.
If it exceeds 0, the copolymerizability tends to decrease. The amount of the macromonomer used is 2 to 50 with respect to 100 parts by weight of the total amount of the copolymerization monomers constituting the graft polymer.
It is preferable to set it as a weight part, and it is more preferable to set it as 5 to 25 weight parts. If the amount of the macromonomer used is less than 2 parts by weight, the effect of forming a graft polymer using the macromonomer tends to be insufficient, while if it exceeds 50 parts by weight, a uniform graft polymer tends to be difficult to obtain. . Such a macromonomer is disclosed in JP-A-61-161
It can be easily produced in accordance with the description in Japanese Patent Publication No. 200548. In addition, from Toagosei Chemical Industry Co., Ltd., etc.
It is commercially available as A-6, AB-6 (above trade name) and the like.

The graft polymer as the component (a) contains the above-mentioned acrylic acid and / or methacrylic acid and a macromonomer as essential components, and if necessary, methyl methacrylate, ethyl methacrylate, -n-propyl methacrylate and methacrylic acid. Acid-n-butyl, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, -n-propyl acrylate, -n-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl methacrylate, benzyl methacrylate, It can be obtained by copolymerizing one or more polymerizable monomers such as 2-hydroxyethyl methacrylate, cyclohexyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, acrylonitrile and styrene.

The graft polymer can be synthesized by a general solution polymerization of the above-mentioned monomer in an organic solvent using a polymerization initiator such as azobisisobutyronitrile, azobisdimethylvaleronitrile and benzoyl peroxide. it can. In this case, examples of the organic solvent used include toluene, p-xylene, dioxane, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and ethylene glycol monoacetate. However, when the film of the photosensitive resin composition is formed by the electrodeposition method, it is preferable to use a hydrophilic organic solvent as the organic solvent.

The weight average molecular weight (converted to standard polystyrene) of the graft polymer of the component (a) is 10,000 to 4
It is preferably set to 0,000. When the weight average molecular weight is less than 10,000, the mechanical strength of the resist tends to be weak, while when it exceeds 400,000, the developability of the photosensitive resin composition tends to be deteriorated. The amount of the graft polymer used as the component (a) is preferably 50 to 85 parts by weight, and more preferably 60 to 75 parts by weight, based on 100 parts by weight of the total amount of the components (a) and (b). More preferable. If the amount used is less than 50 parts by weight, the mechanical strength of the resist tends to be weak, while if it exceeds 85 parts by weight, the proportion of the photopolymerizable monomer that is the component (b) decreases and the sensitivity to light is reduced. Tends to decline.

The monomer having two or more photopolymerizable unsaturated groups in the component (b) is a compound obtained by adding an α, β-unsaturated carboxylic acid to a polyhydric alcohol,
For example, polyethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate,
Glycidyl group-containing compounds such as trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate A compound obtained by adding α, β-unsaturated carboxylic acid to, for example, trimethylamine propane triglycidyl ether triacrylate, bisphenol A glycidyl ether di (meth) acrylate, polyvalent carboxylic acid such as phthalic anhydride Etc. and a compound having a hydroxyl group and an ethylenically unsaturated group, for example, an ester compound such as β-hydroxyethyl (meth) acrylate and the like are used, and further a urethane diacrylate compound having a urethane skeleton It can also be used, in any event, as long as that is cured by light irradiation.

The amount of the component (b) monomer used is (a)
15 parts with respect to 100 parts by weight of the total amount of the component and the component (b)
˜50 parts by weight, more preferably 25 to 40 parts by weight. If the amount used is less than 15 parts by weight, the sensitivity to light tends to decrease, while if it exceeds 50 parts by weight, the mechanical strength of the resist tends to weaken.

As the photoinitiator of the component (c), conventionally used photoinitiators can be used without particular limitation. Specifically, benzophenone, N, N'-tetramethyl-
4,4'-diaminobenzophenone, 4-methoxy-
Aromatic ketones such as 4'-dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone,
Benzoin such as benzoin methyl ether, benzoin ethyl ether, methylbenzoin, ethylbenzoin, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl)-
Examples include 4,5-di (m-methoxyphenyl) imidazole dimer and 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer. These may be used alone or in combination of two or more.

The amount of the (c) component photoinitiator used is (a)
0.1 to 100 parts by weight of the total amount of the component and the component (b)
It is preferably ˜20 parts by weight, more preferably 0.2 to 10 parts by weight. If the amount used is less than 0.1 parts by weight, the photosensitivity of the photosensitive resin composition tends to be low, while if it exceeds 20 parts by weight, light absorption on the surface of the photosensitive resin composition increases during exposure. Therefore, the internal photo-curing tends to be insufficient.

In the photosensitive resin composition of the present invention, if necessary, a thermoplastic resin or a thermoplastic resin such as an ordinary acrylic resin other than the graft polymer of the component (a), a phenol resin, a polyester resin, an epoxy resin, a melamine resin or the like is used. A curable resin can be used. The amount used is preferably 40 parts by weight or less based on 100 parts by weight of the total amount of the components (a) and (b). When the amount used exceeds 40 parts by weight, the compatibility with the component (a) and the sensitivity of the photosensitive resin composition to light tend to decrease.

The photosensitive resin composition of the present invention may further contain other components such as dyes, pigments, fillers, plasticizers, thermosetting agents, flame retardants, polymerization inhibitors and adhesion improvers. It can be used as appropriate.

Next, a method for forming a film containing the photosensitive resin composition of the present invention will be described. The method for forming a film on a substrate is not particularly limited, and for example, the photosensitive resin composition of the present invention described above may be prepared by using acetone, methyl ethyl ketone, toluene, methylene chloride, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, propylene glycol. It is dissolved in an organic solvent such as monomethyl ether, and this solution is directly applied to the substrate by a method such as dip coating, roll coating, curtain coating, spray coating or spin coating, and then the organic solvent is dried to obtain a photosensitive resin composition. Film can be formed.

The carboxyl group in the graft polymer of the component (a) contained in the photosensitive resin composition of the present invention is neutralized with a base such as triethylamine, diethylamine, triethanolamine, and then the photosensitive resin composition is prepared. A photosensitive resin composition may also be prepared by dissolving or dispersing in water to form an electrodeposition bath, immersing a conductive substrate as an anode in this electrodeposition bath, and applying a DC voltage between the counter electrode and electrodeposition coating. A film of material can be formed.

As a preferred method for forming a film, a photosensitive element is prepared by forming a layer of the above-mentioned photosensitive resin composition on a support film, and then laminating this on a substrate to obtain a film on the substrate. Is the way. As a method of forming a layer of the photosensitive resin composition on the support film, for example, the photosensitive resin composition is dissolved in the organic solvent described above, the solution is knife-coated on the support film,
It is performed by applying by a method such as roll coating, spray coating, or spin coating, and drying. The amount of residual solvent in the layer containing the photosensitive resin composition is preferably suppressed to 2% by weight or less from the viewpoint of maintaining the characteristics.

The support film used in the present invention preferably has heat resistance and solvent resistance necessary for producing the photosensitive element, but a release film such as Teflon film or release paper is temporarily used. After forming a layer of the photosensitive resin composition thereon, a film having low heat resistance or solvent resistance is laminated on this layer, and the temporary support film is peeled off. Then, a photosensitive element having a support film having low heat resistance or solvent resistance can be produced. Further, the support film may be transparent or opaque to actinic light. Examples of the support film that can be used include known films such as polyester film, polyimide film, polyamideimide film, polypropylene film and polystyrene film.

When producing a long photosensitive element, the photosensitive element is wound into a roll at the final stage of production. In this case, a backside-treated support film is used by a known method using a pressure-sensitive adhesive tape or the like, so that the layer of the photosensitive resin composition when rolled into a roll is transferred to the back surface of the support film. Can be prevented. For the same purpose, and further for the purpose of preventing the adhesion of dust, it is preferable to laminate a peelable cover film on the layer of the photosensitive resin composition of the element.

Examples of the peelable cover film include polyethylene film, polypropylene film,
There are Teflon films, surface-treated papers, etc., and when peeling the cover film, the adhesive force between the photosensitive resin composition layer and the cover film is stronger than the adhesive force between the photosensitive resin composition layer and the support film. Anything smaller is acceptable.

The thickness of the film of the photosensitive resin composition formed on the substrate by the method described above is usually 5 to 100 μm.

Next, the method for producing the resist pattern of the present invention will be described. The film of the photosensitive resin composition formed on the substrate by the above-described method or the like is imagewise irradiated with an actinic ray, and the photosensitive resin composition in the exposed area is photocured. At this time, when the support film of the photosensitive element is opaque to actinic light, it is necessary to expose the support film after peeling it off. If the support film is transparent to actinic light, it is not necessary to peel the support film during exposure.

As the light source of the active light rays, the wavelength of 30 is used.
Those that emit light of 0 to 450 nm, such as mercury vapor arc, carbon arc, and xenon arc are preferably used. Further, the heat treatment at 50 to 100 ° C. before and after the exposure is preferable in order to improve the adhesion between the substrate and the photosensitive resin film.

Subsequently, in the developing step, that is, by spraying an aqueous solution of alkali such as sodium hydroxide, potassium hydroxide or sodium carbonate, or by immersing it in an aqueous solution of alkali, the unexposed portion is removed to correspond to the above image. A resist pattern having the cured film on the surface of the substrate is prepared. At this time, when exposure is carried out with the support film attached, the support film is peeled off and then developed. It is preferable to irradiate the active ray again after the formation of the resist pattern, since the chemical resistance is improved, particularly when it is used as a plating resist.

[0031]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Synthesis Example 1 of Graft Polymer To a flask equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introducing tube, 500 g of a mixed solvent of methyl cellosolve / toluene = 3: 2 (weight ratio) was added. The mixture was stirred and heated to 85 ° C. while blowing nitrogen gas. When the temperature reached 85 ° C, 50.7 g of methacrylic acid,
Methyl methacrylate 150 g, ethyl acrylate 69.
A liquid obtained by mixing 3 g, 30 g of a macromonomer (trade name AA-6, manufactured by Toagosei Chemical Industry Co., Ltd.) in which one end of a polymer of methyl methacrylate is a methacryloyl group and 2.7 g of azobisisobutyronitrile was mixed. The mixture was dropped into the flask over 5 hours and then kept at 85 ° C. for 3 hours while stirring. After 3 hours, a solution prepared by dissolving 1.2 g of azobisisobutyronitrile in 30 g of methyl cellosolve was added to 10
The mixture was dropped into the flask over a period of minutes, and then the mixture was kept at 85 ° C. for 4 hours while stirring.

The graft polymer (a-1) thus obtained has a weight average molecular weight of 87,000 and an acid value of 1.
It was 08. The solid content of the graft polymer solution was 36.2% by weight.

Synthesis Example 2 of Graft Polymer In a flask similar to Synthesis Example 1 of graft polymer, 500 g of a mixed solvent of methyl cellosolve / toluene = 3: 2 (weight ratio) was added, and the mixture was stirred and blown with nitrogen gas to obtain 8
Warmed to 5 ° C. When the temperature reached 85 ° C, 55.1 g of methacrylic acid, 102 g of methyl methacrylate, 32.9 g of methacrylic acid-n-butyl, acrylic acid-n-
A liquid obtained by mixing 50 g of butyl, 60 g of a macromonomer (trade name: AB-6, manufactured by Toagosei Chemical Industry Co., Ltd.) in which one end of a polymer of n-butyl acrylate is a methacryloyl group, and 1.8 g of azobisisobutyronitrile. To 2.
The mixture was dropped into the flask over 5 hours and then kept at 85 ° C. for 3 hours while stirring. After 3 hours, a solution prepared by dissolving 0.8 g of azobisisobutyronitrile in 30 g of methyl cellosolve was dropped into the flask over 10 minutes, and then 8 times again.
The mixture was kept warm at 5 ° C for 4 hours with stirring.

The graft polymer (a-2) thus obtained had a weight average molecular weight of 112,000 and an acid value of 117. The solid content of the graft polymer solution was 35.9% by weight.

Synthesis Example 3 of Graft Polymer In the same flask as in Synthesis Example 1 of graft polymer, 500 g of a mixed solvent of methyl cellosolve / toluene = 3: 2 (weight ratio) and a polymer of 2-ethylhexyl acrylate were methacryloyl group at one end. Macromonomer solution (Product name AH-6SX manufactured by Toagosei Chemical Industry Co., Ltd.)
50 g (solid content 30 g) was added, stirred and heated to 90 ° C. while blowing nitrogen gas. When the temperature reached 90 ° C., a liquid obtained by mixing 58.2 g of methacrylic acid, 114 g of methyl methacrylate, 50.8 g of ethyl acrylate, 47 g of 2-ethylhexyl acrylate and 2.1 g of azobisisobutyronitrile was added, The mixture was dropped into the flask over 2.5 hours and then kept at 90 ° C. for 3 hours while stirring. Azobisisobutyronitrile 1.0 after 3 hours
A solution obtained by dissolving 30 g of methyl cellosolve in the flask was added dropwise to the flask over 10 minutes, and then the mixture was again kept at 90 ° C. for 4 hours while stirring.

The thus-obtained graft polymer (a-3) has a weight average molecular weight of 95,000 and an acid value of 1.
It was 24. The solid content of the graft polymer solution was 36.1% by weight.

Synthesis of Random Polymer 1 Using the same flask as in Synthesis Example 1 of Graft Polymer, instead of using 30 g of macromonomer having a methacryloyl group at one end of the polymer of methyl methacrylate, the amount of methyl methacrylate used was 150 g. To 180
Random polymer (x-1) was synthesized under the same conditions and method as in Synthesis Example 1 of graft polymer except that the amount was increased to g. The obtained random polymer (x-1) had a weight average molecular weight of 92,000 and an acid value of 108. The solid content of the random polymer solution was 36.1% by weight.

Synthesis of Random Polymer 2 Using the same flask as in Synthesis Example 1 of graft polymer, instead of using 60 g of macromonomer having a methacryloyl group at one end of the polymer of n-butyl acrylate, n-butyl acrylate was used. From 50g to 11
Random polymer (x-2) was synthesized under the same conditions and method as in Synthesis Example 2 of graft polymer except that the amount was increased to 0 g. The obtained random polymer (x-2) had a weight average molecular weight of 119,000 and an acid value of 116. The solid content of the random polymer solution was 35.8% by weight.

Synthesis of Random Polymer 3 In a flask similar to that of Synthesis Example 1 of graft polymer, 30 g of macromonomer in which a polymer of 2-ethylhexyl acrylate is methacryloyl group at one end together with a solvent.
Instead of using 2-ethylhexyl acrylate,
Random polymer (x-3) was synthesized under the same conditions and method as in Synthesis Example 3 of graft polymer except that 0 g was added. The obtained random polymer (x-3) had a weight average molecular weight of 96,000 and an acid value of 123. The solid content of the random polymer solution was 36.0% by weight.

Examples 1 to 6 and Comparative Examples 1 to 3 Photosensitive resin composition solutions were prepared according to the formulations shown in Table 1 (unit: parts by weight), and each solution was made into a 23 μm polyethylene terephthalate film (Toray Industries, Inc.). (Made by Lumirror, Inc.) so that the film thickness after drying would be 35 μm, and after drying, it was covered with a polyethylene film with a thickness of 35 μm to obtain a photosensitive element. Each of the resulting photosensitive elements was laminated onto a test substrate. The laminating conditions were a substrate temperature of 25 ° C., a laminating temperature of 110 ° C., a laminating pressure (air cylinder pressure of a laminator) of 3.5 kgf / cm ² , and a laminating speed of 1.5 m / min.

[0042]

[Table 1]

(1) Photosensitive Property A glass epoxy copper clad laminate (MCL-E-61 manufactured by Hitachi Chemical Co., Ltd.) was used as a test substrate, and the substrates of Examples 1 to 6 and Comparative Examples 1 to 3 were used. A film of the photosensitive resin composition was formed by the above method. 3 to this film through a negative mask
After imagewise exposure with a light amount of 60 mJ / cm ² with an ultrahigh pressure mercury lamp of kW, the polyethylene terephthalate film was peeled off and developed with a 1 wt% sodium carbonate aqueous solution to obtain a resist pattern of 40 μm. Table 2 shows the evaluation results of the photosensitivity and the resist shape of each photosensitive resin composition.

(2) Strength of Tenting Film As a test substrate, a substrate having 1000 through holes plated with copper and having a diameter of 6 mm was used.
6 to 6 and Comparative Examples 1 to 3 were formed by the above method. The entire surface of the film was exposed with a 3 kW ultra-high pressure mercury lamp while adjusting the exposure amount so that each resin composition had 8 ST (step tablet) steps. Then, the polyethylene terephthalate film was peeled off and developed with a 1 wt% sodium carbonate aqueous solution. The broken state of the tenting film on the through hole was visually observed, the ratio of the broken film was examined, and the results are shown in Table 2.

(3) Substrate unevenness followability As a test substrate, on the surface of a glass epoxy copper clad laminate,
Grooves with a width of 100 μm and a depth of 8 μm are provided at intervals of 100 μm.
Using the substrate thus formed, the photosensitive elements of Examples 1 to 6 and Comparative Examples 1 to 3 were laminated on the substrate in the direction perpendicular to the groove to form a film of the photosensitive resin composition. By observing the cross section of the groove with a scanning electron microscope, the filling degree of the photosensitive resin composition in the groove on the surface of the substrate was evaluated, and the results are shown in Table 2.

[0046]

[Table 2]

The graft polymer (a-1) and the random polymer (x-1) have the same composition ratio of the monomers constituting the polymer, but a part of methyl methacrylate is grafted. The graft polymer (a-1) is characteristic. Graft polymer (a-2)
And the random polymer (x-2), the graft polymer (a-3) and the random polymer (x-3)
Is similar, and is characterized in that a part of each of -n-butyl acrylate and 2-ethylhexyl acrylate is grafted. The difference between the graft polymer and the random polymer is shown as the difference in each property shown in Table 2.

Regarding the photosensitivity and the photosensitivity represented by the resist shape, the photosensitive resin compositions of Examples 1 to 6 are superior to those of Comparative Examples 1 to 3.

Further, the photosensitive resin composition of Comparative Example 1 has a larger copolymerization amount of methyl methacrylate in the random polymer than the photosensitive resin compositions of Comparative Examples 2 and 3,
Although the tenting film has high strength and the destruction rate of the film after development is small, it has a problem that the followability to the groove of the substrate is poor due to lack of fluidity. On the contrary, Comparative Examples 2 and 3
The photosensitive resin composition described in (1) copolymerizes a relatively large amount of a monomer such as -n-butyl acrylate or 2-ethylhexyl acrylate that lowers the glass transition temperature of the polymer. Good, but the tenting film has low strength, and the film destruction rate after development is 90.
% Or more indicates that most are destroyed.

On the other hand, in the photosensitive resin compositions of Examples 1 to 6 using the graft polymer of the present invention, the tenting film has a high strength and the film is not destroyed even after the development, and it is heated. It shows that it is fluid when laminated underneath and fills the grooves on the substrate well. As described above, the photosensitive resin composition according to the present invention has a characteristic that both of the properties which are usually contradictory are compatible with each other.

[0051]

INDUSTRIAL APPLICABILITY The photosensitive resin composition of the present invention and the photosensitive element using the same have good photosensitivity, high tenting film strength, and good followability to irregularities of the substrate. Thereby, a good resist pattern can be manufactured, and a high-density and highly accurate printed wiring board can be manufactured.

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Claims (5)

[Claims] 1. An acid value of 20 which is obtained by copolymerizing (a) acrylic acid and / or methacrylic acid with a macromonomer having one polymerizable unsaturated group at one end of a polymer of alkyl acrylate or alkyl methacrylate as an essential component.
To 300 graft polymer, (b) a monomer having two or more photopolymerizable unsaturated groups in the molecule, and (c) a photoinitiator. 2. The macromonomer used in the graft polymer of component (a) is selected from macromonomers having one polymerizable unsaturated group at one end of a polymer of methyl methacrylate, n-butyl acrylate or 2-ethylhexyl acrylate. The photosensitive resin composition according to claim 1, which is only one. 3. A photosensitive element having a layer of the photosensitive resin composition according to claim 1 and a support film. 4. The photosensitive element according to claim 3, further comprising a peelable cover film laminated on a layer of the photosensitive resin composition. 5. The photosensitive resin composition according to claim 1 or 2 is formed as a film on a substrate, actinic rays are imagewise irradiated, the exposed portion is photocured, and the unexposed portion is removed by development. A method of manufacturing a resist pattern, which is characterized by the above.