JPH03250065A - Positive-type photosensitive anionic electrodeposition coating resin composition, and bath and method for electrodeposition coating using the composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. having an excellent photosensitivity, giving a resist film excellent in the mechanical properties, and capable of forming a resist pattern with a high resolution by compounding a specific (meth) acrylic resin with a specific photosensitive material. CONSTITUTION:The title compsn. comprises 30-95 pts.wt. resin obtd. by neutralizing, with a base, a (meth)acrylic resin which has an acid value of 30-250 and is obtd. by the copolymn. of two essential monomers, i.e., (meth)acrylic acid and a polymerizable monomer of which a homopolymer has a glass transition point of 0 deg.C or lower and 5-70 pts.wt. compd. of formula 1 (wherein R<1> is alkyl; R<2> is H, alkyl, alkoxy, or nitro; R<3> is formula II; and (m) is an integer of 0-2, (n) is an integer of 1-3, and (m+n) is an integer of 1-3), the sum of the two components being 100 pts.wt.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a positive photosensitive anionic electrodeposition coating resin composition used for forming resist patterns in the manufacture of photosensitive circuit boards, etc. This invention relates to an electrodeposition coating bath and an electrodeposition coating method.

(Prior Art) Conventionally, as a method for forming a resist pattern on the surface of a substrate, a method is often used in which a photosensitive layer is formed on the surface of the substrate, and then, after being irradiated with actinic rays, the layer is developed. Various methods are employed for forming the photosensitive layer in this step.

For example, a method using a photosensitive resin composition solution (coating liquid) such as dip coating, roll coating, or curtain coating, or a method in which a photosensitive layer is previously formed on a base film (hereinafter referred to as photosensitive film) is applied to the substrate surface. A method of laminating layers using a laminator or the like is known. Among these methods, the method using a photosensitive film is currently adopted as the mainstream method in the field of printed circuit board manufacturing, because it can easily form a photosensitive layer with a uniform thickness.

(Problems to be Solved by the Invention) Recently, as printed circuit boards have become denser and more precise, resist patterns of higher quality have become necessary. That is, it is desired that the resist pattern be free of pinholes and that is in close contact with the surface of the underlying substrate. It is known that the currently mainstream method of laminating photosensitive films has limitations in meeting such demands.

This method has poor ability to follow irregularities on the substrate surface caused by dents during substrate manufacturing, nonuniform polishing, and nonuniformity of bits of copper plating on the surface of the mesh 9 of the glass cloth in the inner layer of the substrate. , it is difficult to obtain sufficient adhesion. This difficulty is solved by laminating photosensitive films under reduced pressure (
This problem can be avoided to some extent by using the Japanese Patent Publication No. 59-3740), but this requires particularly expensive equipment.

For these reasons, solution coating methods such as dip coating, roll coating, and curtain coating have been reconsidered in recent years.

However, these coating methods have problems such as difficulty in controlling the film thickness, insufficient uniformity of the film thickness, and occurrence of pinholes.

Therefore, a new method has recently been proposed in which a photoresist film is formed by electrodeposition coating (% aperture 62-23549
(See Publication No. 6). This method improves the adhesion of the resist. ■Good ability to follow irregularities on the substrate surface. ■A photoresist film with uniform thickness can be formed in a short time. ■Because the coating liquid is an aqueous solution.

It has advantages such as preventing contamination of the working environment and causing no problems in terms of disaster prevention.

Several proposals have been made in the past regarding positive type photosensitive electrodeposition paints that are considered to be particularly effective in manufacturing printed circuit boards having through holes.

Most of them are of the type in which a photosensitive group such as 1,2-naphthoquinonediazide is introduced into the polymer molecule (for example, JP-A-61
-206293, JP-A No. 63-221177, JP-A No. 64-4672) have advantages such as easy control of the electrodeposition liquid from the viewpoint of coating, but on the other hand,
From the perspective of a positive photoresist, there were problems such as insufficient photosensitive properties, low mechanical strength of resist 1, and furthermore, it was difficult to finely adjust various properties.

On the other hand, when forming positive photoresist '6 using a solution coating method used in the manufacturing process of semiconductor devices such as ICs and LSIs, most of the composition of the positive photoresist used is novolak resin or vinyl phenol resin. It is a mixture of an alkali-soluble resin of -3053
No. 48 9% No. 1986-279246 1% No. 64 = 1
No. 1259 1% Publication No. 17049/1984).

These resins have good photosensitivity and mechanical properties of the resist film when viewed from the performance as positive photoresists, but this is natural because these resins do not contain carboxyl groups, which are essential for anionic electrodeposition paints. However, it cannot be used as an electrodeposition paint as it is.

Furthermore, (meth)acrylic resin has traditionally been used as the main component of photoresists used in the production of printed circuit boards, which is the main application of the present invention, due to its physical properties and ease of handling. The ester compound of penzophenone 1゜2-naphthoquinonediazide sulfonic acid having two or more hydroxyl groups, which is commonly used as a photosensitizer, has extremely poor compatibility with (meth)acrylic resin, so it is difficult to use as a photosensitizer. It cannot be used in combination with (meth)acrylic resin as the main component.

Furthermore, a method has been proposed in which a positive photoresist is formed by applying a coating liquid containing a mixture of an acrylic resin having a carboxyl group and a photosensitizer (Patent Publication No. 51-14042). However, the naphthoquinonediazide sulfonic acid ester of p-cumylphenol that is frequently used in the examples of this application is
- Esterified products of naphthoquinone diazide sulfonic acid are not particularly compatible with acrylic resins, and their compositions also have low photosensitivity.

In addition, as a developing solution suitable for resist) K having this composition after exposure, an aqueous alkanolamine solution or a solution containing both an amine and an alcohol is suitable, and an alkaline developer is not suitable. However, most of the developing solutions used in the aforementioned tenting method using photosensitive film, which is the mainstream manufacturing method for printed circuit boards at present, mostly use alkali.

Even in the case of the method of forming photoresist by electrodeposition coating,
It goes without saying that it is desirable to use an alkali developer that follows the current method. In this sense, it can be said that this composition has no versatility.

Further, even though this composition has carboxyl groups in the resin, it cannot be used as an electrodeposition paint as it is. That's 1! In the case of deposited coatings, if the glass transition point of the deposited film is not low, in other words, the minimum film forming temperature (MFT)
This is because a film will not be formed after electrodeposition unless the value is low. Therefore, the monomer composition of the acrylic resin also needs to take this point into consideration.

As mentioned above, the positive photoresist compositions formed with electrodeposition paints that have been proposed to date have low photosensitivity and mechanical properties of the resist film, and furthermore, it is difficult to finely adjust the properties. Although positive photoresists formed by coating methods using solutions have good properties, it is impossible to weigh them directly for various reasons. It was b.

(Means for Solving the Problems) As a result of intensive study, the present inventors found that a carboxyl group-containing resin that is currently commonly used as the main component of photoresists used in the manufacture of printed circuit boards (
Choose meth) acrylic resin.

(Meth)acrylic resin In order to obtain an excellent electrodeposition coating, it is essential to copolymerize a polymerizable monomer whose homopolymer has a glass transition point of 0° C. or lower.

Furthermore, by combining a photosensitizer with unprecedented compatibility with the 7t (meth)acrylic resin obtained in this way, it can be formed by electrodeposition coating with excellent photosensitivity and mechanical properties of the resist film. A positive photosensitive anionic electrodeposition coating resin composition having the following.

We have discovered an electrodeposition coating bath and an electrodeposition coating method using this.

In other words, one aspect of the present invention is.

fal A resin obtained by neutralizing (meth)acrylic resin with a base of 30 to 250, which is copolymerized with acrylic acid and/or methacrylic acid and a polymerizable monomer whose homopolymer glass transition point is 0°C or lower as an essential component. (a)
and 30 to 95 parts by weight based on 100 parts by weight of the total amount of (b) and tb+ The compound represented by the following general formula (I) (O
R3)n (wherein R1 is an alkyl group and R2 is hydrogen or an alkyl group.

Alkoxy group or nitro group R3 is all shown, mFi is an integer of 0 to 2, n is an integer of 1 to 3, and selected so that the sum of 9m and n is an integer of 1 to 3)
.

5 to 70 parts per 1 oz total amount of (a) and (b)
The present invention relates to a positive photosensitive anionic electrodeposition coating resin composition containing parts by weight, and an electrodeposition coating bath using the same.

The present invention relates to an electrodeposition coating method characterized in that a substrate whose surface is covered with metal is crushed in the electrodeposition coating bath, and a DC voltage is applied using the substrate as an anode.

According to the present invention, it is more suitable for electrodeposition coating than ever before.

In addition, a positive photoresist having excellent photosensitivity and resist mechanical properties can be provided, and thereby the many advantages of forming a photoresist by electrodeposition coating described above can be fully exhibited.

The nine inventions will be described below.

The (meth)acrylic resin which is the component (a) first requires the use of acrylic acid or methacrylic R71i as a carboxyl group-containing polymerizable monomer.

The acid value of the (meth)acrylic resin obtained is 30.
It feels like it's in the range of ~250. If the acid value is less than 30, it becomes the invention.After adding a base to the positive photosensitive anionic electrodeposition coating resin composition as described below, water dispersibility and water dispersion stability when water is added and dispersed are affected. 9 compositions precipitated. ! If the acid value exceeds 250, the appearance of the coating after electrodeposition will be poor. Acrylic acid or methacrylic acid may be used alone or in combination.

As another essential component of the (meth)acrylic resin, which is a component of (al), a polymerizable monomer whose homopolymer glass transition point is 0°C or lower is used. Polymerization occurs when the homopolymer glass transition point is 0°C or lower. The term "polymer monomer" means that the glass transition point of the polymer obtained by homopolymerizing the monomer is 0°C or lower.The glass transition point is measured by a normal thermal analysis method, but preferably by differential analysis. It is carried out by scanning calorimetry (DSC).Polymerizable monomers whose homopolymer glass transition point is 0°C or lower include ethyl acrylate, inpropyl acrylate,
n-propyl acrylate, isobutyl acrylate,
n-hexyl methacrylate, n-octyl methacrylate, n-decyl methacrylate, etc.
-Bunal acrylate and 2-ethylhexyl acrylate are preferred. These polymerizable monomers may be used alone or in combination of two or more, and the amount used is equal to the total amount of copolymerizable monomers forming the polymer component (a).
The amount is preferably 5 to 75 parts by weight, more preferably 20 to 60 parts by weight. When the amount used is less than 5 parts by weight, the glass transition point of the polymer becomes high, and there is a fear that a film may not be formed when the electrodeposition paint combined with the photosensitive agent (component (b)) is electrodeposited. On the other hand, if it exceeds 75 parts by weight, the glass transition point of the polymer becomes too low and the coating film after electrodeposition tends to become sticky.

In addition to the polymerizable monomers mentioned above, the (meth)acrylic resin that is the component (a) includes, for example, methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, 222-trifluoroethyl methacrylate.

Diacetone acrylamide, acrylonitrile.

Copolymerization can be carried out by using one or more types of single-vessel polymerizable motumer such as styrene/vinyltoluene in combination. The amount used can be 91 parts by weight or less based on 100 parts by weight of the total 11i of the copolymerized monomers forming the resin, which is the component ta).

The (meth)acrylic resin, which is the component of +8), can be synthesized using a general method using a polymerization initiator such as azobisisobutyronitrile, azobisdimethylvaleronitrile, or benozoyl peroxide. It can be carried out by solution polymerization. In this case, the organic solvent to be used is preferably a hydrophilic organic solvent such as dioxane, methoxyethanol, ethoxyethanol, diethylene glycol, etc., considering that it will be used in an electrodeposition coating. If a hydrophobic organic solvent such as toluene, xylene, or benzene is mainly used, it is necessary to distill off the solvent after resin synthesis and replace it with the hydrophilic organic solvent. The average molecular weight of the resin (in terms of standard polystyrene) is 5.000 to 150,
000 is preferred. If it is less than 5,000, the mechanical strength of the resist is weak; if it exceeds 150,000, the electrodeposition coating properties tend to be poor and the appearance of the coating film tends to be poor.

The amount of (meth)acrylic resin used as component (a) is (
30 to 95 parts by weight per 100 parts by weight of the total amount of al and (b)
Parts by weight. More preferably, the amount is 50 to 90 parts by weight. If the amount used is less than 30 parts by weight, the water dispersibility and water dispersion stability in the electrodeposition bath will be poor, and if it exceeds 95 parts by weight, the proportion of the photosensitive material, which is the component (b), will decrease and the sensitivity to light will decrease. descend.

Next, the compound represented by the general formula (I1) which is a component of K(b) will be explained.

R1 in the general formula +1) is an alkyl group, preferably an alkyl group having 1 to 18 carbon atoms, and 3% has 1 to 1 carbon atoms.
The alkyl group 1 of 2 is preferably, for example, methyl, n-propyl, inglovir, n-octyl, 2-ethylhexyl, n-dodecyl group, or the like.

Moreover, R2 is hydrogen, methyl, ethyl, or n-propyl.

Inglovir, n-butyl, isobutyl, t-butyl,
Alkyl groups such as n-hexyl, methoxy.

Any one is selected from alkoxy groups such as ethoxy, propoxy, butoxy groups, and nitro groups.

υ, 9m is an integer from 0 to 2, n is an integer from 1 to 3, and 1
The sum of m and n is selected to be an integer from 1 to 3.

The method of synthesizing the compound of general formula (I) is not particularly limited.

Preferably trihydroxybenzoic acid ester (e.g. gallic acid ester), dihydroxybenzoic acid ester,
1,2-benzoquino/diazide-4- to benzoic acid ester derivatives having a hydroxyl group on the benzene ring such as hydroxybenzoic acid ester (e.g. salicylic acid ester)
It can be obtained by condensation reaction of sulfonic acid chloride or 1,2-7toquinonediazide-4-sulfonic acid chloride. To give a specific example, a benzoic acid ester derivative having a hydroxyl group on the benzene ring and 1.2-
Add an organic solvent to a mixture of benzoquinonediazide-4-sulfonic acid chloride or 1,2-naphthoquinonediazide-4-sulfonic acid chloride to dissolve it, and add triethylamine, pyridine, and sodium carbonate (
- For boat fishing, a base such as an aqueous solution is added dropwise, and after one drop, the mixture is further stirred for 10 minutes to 8 hours to react.

During this time.

The temperature is preferably maintained at room temperature to 80°C, particularly 30 to 50'C.

In this way, benzoquinone diazide sulfo/acid chloride or naphthoquino/diazide sulfonic acid chloride may be entirely condensed onto the hydroxy groups, or some of the hydroxy groups may be left and the remainder condensed. Furthermore, as can be seen from the above synthesis example, there is a possibility that a mixture of compounds having different amounts of unreacted hydroxyl groups in one molecule may be obtained, but it is not necessary to isolate them. In any case, the compound of general formula (I) is a compound selected such that 9m is an integer of O to 2, n is an integer of 1 to 3, and the sum of 1m and n is an integer of 1 to 3. For example, both single products and mixtures fall within the scope of the present invention.

The amount of the compound of general formula (I), which is the component (b), is:

5 to 70 for a total of 100 major prizes for (a) and (b)
It is preferably 10 to 50 parts by weight. If the amount used is less than 5 parts by weight, the sensitivity to light will decrease, and if it exceeds 70 parts by weight, water dispersibility and water dispersion stability in an electrodeposition bath will deteriorate.

In addition to the above-mentioned (a) and (bl components), the positive-working photosensitive anionic electrodeposition paint resin composition of the present invention may contain a small amount of a chino/diazide compound used in two ordinary positive-working photosensitive resin compositions. I can do it.

Examples of the chino/diazide compound include 1.

2,3.4-11 hydroxybe/siphenon-1,2~
Naphthoquinone diazide-5-sulfonic acid ester.

2,3.4.4'-Tetrahydroxybenzophenone-
Examples include 1,2-naphthoquinonediazide-5-sulfonic acid esters of polyhydroxybenzophenone such as 1.2-naphthoquinonediazide-5-sulfonic acid ester. The amount of these quinonediazide compounds used is preferably 10 parts by weight or less based on 100 parts by weight of the total amount of components (a) and (b). If it exceeds 10 parts by weight, the compatibility with the (meth)acrylic resin of component (a) tends to decrease, and the water dispersion stability tends to decrease.

Furthermore, a sensitizer can also be blended into the positive photosensitive anionic electrodeposition coating resin composition of the present invention.

Examples of the sensitizer include virol, imidazole, triazole, indole, benzimidazole, oxazolidone, piperidone, hydantoin, glycine,
Nitrogen-containing compounds having active hydrogen such as barbylic acid and its derivatives can be mentioned. The amount of these sensitizers used is preferably 30 parts or less per part aft I O0 of the components (a) and (bl).

If it exceeds 30 layers, the solubility of the resist increases during development, and the residual film rate tends to decrease.

In addition to ζ, dyes, pigments, plasticizers, adhesion promoters, inorganic fillers, etc. can also be used as appropriate in the positive photosensitive anionic electrodeposition coating resin composition of the present invention.

In order to convert the positive photosensitive anionic electrodeposition paint resin composition of the present invention containing the above-mentioned components (a) and (b) as main components into an electrodeposition paint, first the components (a) and (b) are .

Furthermore, although it is desirable that each of the above-mentioned components used as necessary be uniformly dissolved in a hydrophilic organic solvent, it is not necessary to be particular about this. The hydrophilic organic solvent mentioned here includes, for example, dioxa/methoxyethanol, ethoxyethanol, dietele/glycol, and the like. These solvents may be used alone or in combination of two or more, and the amount used is preferably 300 parts by weight or less per 100 parts by weight of the total solid content.

Next, a base is added to this solution (to neutralize the carboxyl groups contained in the (meth)acrylic resin that is a component of at, thereby making it easier to water-solubilize or water-disperse the 9 composition. As a base to use.

There are no particular limitations, but examples include triethylamine, monoethanolamine, jetanolamine, diisopropylamine, and dimethylaminoethanol.

Examples include morpholine, ammonia, sodium hydroxide, etc., and these can be used alone or in a mixture of two or more. The amount of these bases used is 0 per equivalent of carboxyl group in the (meth)acrylic resin as component (a).
．． 4 to 1.0 equivalents are preferred.

If the amount is less than 0.4 equivalent, the water dispersion stability in the electrodeposition coating bath will decrease, and if it exceeds 1.0 equivalent, the coating film (photosensitive layer) after electrodeposition coating will deteriorate.
The thickness tends to become thinner and the storage stability tends to decrease, which is not preferable.

Next, water is added to dissolve or disperse the positive photosensitive anionic electrodeposition coating resin composition in water to prepare an electrodeposition coating bath. The solid content of the electrodeposition coating bath is usually 5 to 20% by weight, and the pH
is preferably in the range of 7.0 to 9.0. If pfl is less than 7.0, dispersion may deteriorate and electrophoresis may become difficult. If I)H exceeds 9.0, the film deposited with -H11L may be redissolved, and as a result, no film may be formed. pHk
In order to adjust to the above preferred range, the above-mentioned base may be added later.

Furthermore, in order to improve the water dispersibility and dispersion stability of the positive photosensitive anionic electrodeposition coating resin composition, a nonionic, cationic, anionic, or other surfactant may be added as appropriate.

Furthermore, a hydrophobic solvent such as toluene, xylene, 2-ethylhexyl alcohol, etc. can be added as appropriate to increase the coating time during electrodeposition coating.

The electrodeposition coating bath thus obtained was used to coat the substrate surface (
In this case, the substrate surface is iron or aluminum.

For electrocoating (coated with metals such as copper, zinc, and other metals and alloys), the substrate is immersed in an electrocoat bath as an anode, and a DC voltage of usually 50 to 400 V is applied for 10 minutes. It is applied for 15 minutes. At this time, it is desirable to control the temperature of the electrodeposition coating bath at 15 to 30°C.

After electrodeposition, the object to be coated is taken out of the coating bath, washed with water, drained, and dried with hot air. At this time, if the drying temperature is high, there is a risk that the quinone diazide group in the positive photosensitive anionic electrodeposition paint resin composition will decompose.
It is preferable to dry at 0°C or lower.

The thickness of the eardrum (photosensitive layer) obtained in this way is 2 to 50 μm.
is preferred. If the film thickness is less than 2 μm, developer resistance is low;
Furthermore, when used in the manufacture of printed circuit boards, for example, when etching is performed after forming a resist pattern, the resistance to etching liquid and etch factor tend to be poor, and if the film thickness exceeds 50 μm, the resolution of the resist pattern decreases. It may decrease.

Next, the coating film is irradiated with actinic rays in the form of a th image to photodecompose the exposed areas, and then the exposed areas are removed by development to obtain a resist pattern.

Examples of active light sources include those that emit light with a wavelength of 300 to 450 nm9, such as a mercury vapor arc.

Carbon arc, xenon arc, metallolide arc, etc. are preferably used.

Development is usually carried out by spraying alkaline water such as sodium hydroxide, sulfur rum carbonate, or potassium hydroxide, or by immersing the film in alkaline water.

(Example) The present invention will be explained below with reference to Examples.

First, a method for synthesizing component (a) and component (b) used in Examples will be described.

Synthesis of (meth)acrylic resin as component (a) (a-1) Add 900 g of dioxane to a flask equipped with a stirrer, a reflux condenser, a thermometer, two dropping funnels, and a nitrogen gas introduction tube,
While stirring, a gas mixture was blown into the mixture and the mixture was heated to a temperature of 90°C. After the temperature is constant at 90℃, the acrylic #
11419. 2. A mixture of 559 g of methyl methacrylate 3009.2-ethylhexyl acrylate and 109 g of azobisisobutyronitrile. ．． The mixture was added dropwise into the flask over a period of 5 hours, and after -f: the mixture was kept at 90° C. for 3 hours with stirring. After 3 hours, a solution of 3 g of azobisisobutyronitrile dissolved in 7,100 g of dioxa was added dropwise into the flask over 10 minutes, and then kept at 90° C. for 4 hours with stirring.

The weight average molecular weight of the resin component (a) thus obtained was 42,000. The acid value was 108. Moreover, the solid content of the resin solution was 50.2 weight %.

(a-2) Dioxane 1.1309 was added to a flask equipped with the same apparatus as in (a-1), and while stirring, nitrogen gas was blown into the flask and the flask was heated to a temperature of 90°C. The temperature remains constant at 90℃ f
c By the way, methacrylic acid 1089, methyl methacrylate 330g, n-butyl acrylate 462g, 2-
A mixture of 100 g of hydroxyethyl acrylate and 109 g of azobisisobutyronitrile was added dropwise into the flask over 25 hours, and then kept at 90° C. with stirring for 3 hours. After 3 hours, a solution of 3 g of azobisisobutyronitrile dissolved in 100 g of dioxane was added dropwise into the flask over 10 minutes, and then kept at 90° C. for 4 hours with stirring.

The weight average molecular weight of the resin as component (a) thus obtained was 56.000, and the acid value was 71.7.

The solid content of the applied resin solution was 44.6 parts.

(Synthesis of photosensitizer for bl component (b-11 2-ethylhexyl gallic acid 28.29 (0.1 mo
A solution of 80.49 (0,3 rno/) and 1,2-naphthoquinonediazide-4-sulfonic acid chloride in 800 rnl of dioxane was heated at 40°C with stirring.
Triethylamine 329e was added dropwise thereto over 30 minutes. After the dropwise addition, the reaction was further carried out at 40°C for 3 hours, and then the 9 reactants were reduced to 0. The mixture was poured into an aqueous solution of IN hydrochloric acid, and the resulting precipitate was filtered using a FF filter to obtain ester compound 919 of 2-ethylhexyl gallate and 1,2-naphthoquinonediazide-4-sulfonic acid.

Example 1 To the resin solution 809 (solid content 40.29) of (a-1) was added (
b-1) photosensitizer 129 and triethylamine 3.39
was dissolved and then dispersed in water while slowly adding water 4009 dropwise to obtain an electrodeposition bath (pH 7.3).

Example 2 To 90 g (solid content 40.19) of the resin solution of (a-2) was added (
5 g of the photosensitizer b-1) and 2.69 g of triethylamine were dissolved and then 400 g of water was slowly added dropwise to obtain a water-dispersed electrodeposition coating bath (pH 7.7).

Each of the materials obtained in Examples 1 to 4 was applied to a coating bath using a glass epoxy steel clad laminate (MCL-E-61 manufactured by Hitachi Chemical Co., Ltd.) as an anode, and a stainless steel plate (SUS304) (shape 200 m).
X 75 m X 1! IOD) K was crushed as a cathode, and a DC voltage of 150V was applied for 3 minutes at a temperature of 25°C to form an electrodeposition coating I (photoresist film) on the surface of the steel clad laminate. Thereafter, the film was washed with water, drained, and dried at 8°C for 15 minutes (each film thickness after drying was 7i, as shown in Table 1).

Next, these coating films were imagewise exposed to a 3 kW ultra-high pressure mercury lamp through a photomask, and then developed with a 1 liter aqueous sodium carbonate solution. In order to evaluate the photosensitivity at this time, a step tablet (using a photomask with an optical density of 0.05 as the first stage and an optical density of d! increasing by 0.15 for each stage) was used to obtain three stages. The exposure amount was measured (results are shown in Table 1). It is shown that all examples have high sensitivity. Furthermore, it was confirmed that all of the obtained resist patterns had a high resolution of 50 μm.

Table 1 (Effects of the invention) By applying the electrodeposition coating method of the present invention to an electrodeposition coating bath using the positive photosensitive anionic electrodeposition paint resin composition of the present invention, high sensitivity and high resolution can be achieved. A resist pattern can be formed.

The resist obtained by using the present invention can be used as a relief, or can be used to form a photoresist for etching or plating using a copper-clad laminate as a substrate.

Claims (1)

[Claims] 1. (a) (methacrylic acid) having an acid value of 30 to 250, which is copolymerized with acrylic acid and/or methacrylic acid and a polymerizable monomer whose homopolymer glass transition point is 0°C or lower as an essential component. ) A resin obtained by neutralizing an acrylic resin with a base (a)
and 30 to 95 parts by weight based on 100 parts by weight of the total amount of (b) and (b) a compound represented by the following general formula (I). ^1 is an alkyl group, R^2 is hydrogen, an alkyl group, an alkoxy group, or a nitro group, R^3 is a ▲numerical formula, chemical formula, table, etc.▼, m is an integer from 0 to 2, and n is from 1 to is an integer of 3,
selected so that the sum of m and n is an integer of 1 to 3) 5 to 70 parts per 100 parts by weight of the total amount of (a) and (b)
A positive photosensitive anionic electrodeposition coating resin composition containing parts by weight. 2. The positive-working photosensitive anionic electrodeposition coating resin composition according to claim 1, wherein the polymerizable monomer whose homopolymer has a glass transition point of 0 DEG C. or lower is n-butyl acrylate and/or 2-etherhexyl acrylate. 3. The positive-working photosensitive anionic electrodeposition coating resin composition according to claim 1 or 2, wherein R^1 of the compound represented by general formula (I) is an alkyl group having 1 to 18 carbon atoms. 4. An electrodeposition coating bath comprising the positive photosensitive anionic electrodeposition coating resin composition according to claim 1, 2 or 3. 5. An electrodeposition coating method comprising immersing a substrate whose surface is covered with metal in the electrodeposition coating bath according to claim 4, and applying a DC voltage using the substrate as an anode.