JPS581140B2 - photosensitive composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to photosensitive compositions.

More specifically, a copolymer containing a conjugated diene hydrocarbon and an α,β-ethylenically unsaturated carboxylic acid as essential components, which can be used in an organic solvent or an alkaline solvent as a developer, and a photosensitized The present invention relates to a photosensitive composition particularly suitable as a photoresist, which contains a photocrosslinking agent and/or a photocrosslinking agent.

As a photoresist for metal corrosion, it is exposed to light under a specified negative image, and upon development, the exposed area becomes insoluble and the unexposed area is eluted and removed, resulting in chemical resistance of the copy of the original image. things are used.

However, until now, there have been few reports that satisfy all of the general performances required of photoresists as described below.

(1) High sensitivity.

(2) Excellent resolution.

(3) The coating film should have good uniformity in thickness and should not show adhesion to the negative image.

(4) The cured photoresist film is tough and has excellent chemical resistance.

(5) Sufficient adhesion to the substrate.

(6) High storage stability.

(The photoresist and developer must not be a source of pollution.

Conventionally, as resists for metal corrosion, compositions in which dichromate is combined with water-soluble polymers such as egg white, gelatin, fish glue, and polyvinyl alcohol, or compositions made of cyclized rubber-diazide have been widely used. Ta.

The former composition has features such as excellent resolution, but it has poor storage stability as it gradually deteriorates naturally even in the dark and becomes unusable (called dark reaction). Another drawback is that pollution problems due to chromium emissions are unavoidable.

Although the latter cyclized rubber composition can solve the problem of dark reaction, since the photosensitive solution and developer are organic solvents, the problem of pollution due to scattering into the atmosphere cannot be avoided.

The present inventors have investigated various conjugated diene polymers, and found that a copolymer of a conjugated diene hydrocarbon and an α,β-ethylenically unsaturated carboxylic acid can be used as a photoresist with high sensitivity and excellent resolution. found that it can be used,
As a result of intensive research, we have arrived at the present invention.

That is, the present invention provides (■) a conjugated diene hydrocarbon (A)
α,β-ethylenically unsaturated carboxylic acid (B) is an essential component, and a monoolefinic unsaturated compound (C) is added to this as an essential component. A: 10 to 95 mol%, B: 5 to 90 mol%, C: 0
This is a photosensitive composition comprising a copolymer in a proportion of ~85 mol% and (II) a photosensitizer and/or a photocrosslinking agent. It is not only possible to develop with an alkaline solvent such as, but also with an organic solvent similar to that used for cyclized rubber compositions.

Even though the photoresist made of the composition of the present invention is developed with an alkaline solvent such as a dilute aqueous alkali hydroxide solution, it has no solubility in water or acids, and the photoresist can be rinsed with water after development, and the pattern It has the feature of very strong acid resistance even without the baking process.

When a photoresist made of the composition of the present invention is used, the resist film that is no longer needed after etching can be peeled off by immersing it in a concentrated strong alkaline aqueous solution.

Conjugated diene hydrocarbon (A) that can be used in the present invention and α,
In the copolymer consisting of β-ethylenically unsaturated carboxylic acid (B) and monoolefinic unsaturated compound (C), the content of copolymer component A is 10 to 95 mol%, preferably 1
0 to 70 mol%, the content of copolymer component B is 5 to 90 mol%, preferably 5 to 60 mol%, and the content of copolymer component C is 0 to 85 mol%. can.

Examples of the conjugated diene hydrocarbon of copolymer component A include butadiene, isoprene, dimethylbutadiene, chlorobrene, etc., and these can be used alone or in combination.

Examples of the α,β-ethylenically unsaturated carboxylic acid of copolymer component B include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, monoethyl maleate, citraconic acid, etc. Like A, it can be used alone or in combination.

The monoolefinic unsaturated compound of copolymer component C includes styrene, α-methylstyrene, vinyltoluene,
Examples include p-methoxystyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, methacrylic ester, and acrylic ester, which can be used alone or in combination.

As the methacrylic ester and acrylic ester, methyl methacrylate, ethyl methacrylate, probyl methacrylate, methyl acrylate, n-butyl acrylate, etc. are preferably used.

If the proportion of copolymer component A is less than 10 mol%, sufficient cross-linking reaction between the polymers will not occur, and the photoresist will have low sensitivity and cannot be put to practical use, and will have low chemical resistance. Put it away.

On the other hand, if it exceeds 95 mol %, the amount of copolymer component B will be relatively small and problems will arise in terms of adhesion to negative images, which is not preferable.

The preferred range of copolymer component A is 10 to 70 mol%.

When the amount of α,β-ethylenically unsaturated carboxylic acid in copolymer component B becomes small, that is, when the amount of copolymer component B becomes less than 5 mol %, development with a dilute alkaline solvent becomes impossible.

If the copolymer component B exceeds 90 mol %, it is not preferable because not only the adhesion to the substrate decreases but also the penetration of the metal during etching increases.

The preferred range of copolymer component B is 5 to 60 mol%.

When copolymer component C exceeds 85 mol%, the relative proportion of copolymer components A and B decreases, leading to a decrease in sensitivity and developability with alkaline solvents, which is not practical.

Copolymer component C does not need to be used, but if used, it is effective in improving the toughness of the film.

Particularly preferred ranges are A: 30 to 60 mol%, B: 10
-50 mol%, C: 0-60 mol%.

The photosensitizer used in the present invention includes those used as ordinary photoreaction initiators, such as α-diketone compounds such as diacetyl and benzyl, acyloins such as benzoin and pivaloin, benzoin methyl ether, benzoin isopropyl ether, etc. Polynuclear quinones such as acyloin ethers, anthraquinone, and 1,4-naphthoquinone are mentioned.

The photocrosslinking agents used in the present invention include diazidochalcone, 4,4'-diazidostilbene, 4,4'-diazidostilbene-2,2'-disulfonic acid, 2,6
-Diazide compounds such as -bis(p-azidobenzal)cyclohexanone can be mentioned.

These photosensitizers or photocrosslinking agents may be used alone or in combination in an amount of 0.1 to 1 part by weight per 100 parts by weight of the copolymer.
It is used in the range of 0 parts by weight, preferably in the range of 1 to 5 parts by weight.

The photosensitive composition of the present invention also includes hydroxy aromatic compounds such as hydroquinone, methoxyphenol, and p-tert-butylcatechol, benzoquinone, and p-tert-butylcatechol as stabilizers.
- Compounds such as quinones such as tolquinone and p-xyquinone, and amines such as phenyl-α-naphthylamine, within a range that does not hinder curing by light, that is, copolymer 10
It can be added in an amount of 0.01 to 5 parts by weight relative to 0 parts by weight.

In order to effectively use the composition of the present invention, it is necessary to select a developer, and the photoresist of the present invention can be developed not only with aromatic hydrocarbons and alcohols such as toluene and xylene, but also with ammonia, It is easily developed because it has very high solubility in dilute aqueous solutions of amines and alkali hydroxides, and when washed with water after development, a pattern faithful to the original image can be obtained.

The pattern thus obtained has high adhesion to the metal substrate and is sufficiently resistant to etching even if the step of baking the pattern at high temperature is omitted.

After etching without high-temperature baking, it is necessary to peel off the unnecessary resist, but simply immerse it in a concentrated alkaline aqueous solution with a concentration of 10% or more for a few minutes, or in an ester such as n-butyl acetate for a few minutes. It has the feature that it can be removed with the concentrated alkaline aqueous solution mentioned above, even if it has been baked at high temperatures. It is also worth mentioning that it is not necessary.

Next, the present invention will be explained in more detail with reference to Examples.
It goes without saying that the present invention is not limited to the following examples.

Example 1 Butadiene/styrene/methyl methacrylate/methacrylic acid polymerized using methanol as a solvent = 45/10/3
62.8 of a copolymer with a composition of 0/15 (mole ratio)
15.9 g of wt% methanol solution (10
g) with 0.0% of 2,6-bis(p-azidobenzal)cyclohexanone as a photocrosslinking agent. 3 g of the copolymer and 0.1 g of hydroquinone as a stabilizer were mixed, and the total amount was made up to 67 g with xylene to prepare a 15% by weight solution of the copolymer.

onto a grained aluminum plate with a thickness of 0.3 mm.
A resist layer having a dry thickness of 12 μm was formed using a spin coating device (Whaler manufactured by Dainippon Screen).

Using a 250 W ultra-high pressure mercury lamp, the negative image was exposed to light with an intensity of 80 W/m2 for 10 seconds, and then developed with toluene, resulting in a positive image faithful to the original image.

Etching was performed by 0.17 mm by adding copper sulfate to 10% hydrochloric acid water, but the resist film did not peel off at all and a good relief image was obtained.

The resist film adhering to the surface could be peeled off by immersing it in n-butyl acetate and then rubbing it lightly.

Example 2 A resist layer was similarly formed on a copper plate using the photosensitive solution used in Example 1, and after exposure, development was performed using a 0.5% sodium hydroxide aqueous solution, and a good positive image was obtained. .

Example 3 Isoprene polymerized using ethanol as a solvent/styrene/ethyl methacrylate/methacrylic acid = 50/10/2
Ethanol was removed from a copolymer solution having a composition of 0/20 (molar ratio) under reduced pressure, and a 10% solution was prepared using a 2% aqueous sodium hydroxide solution. .2'-disulfonic acid at 2% by weight of the copolymer
This was added to make a homogeneous solution.

In the same manner as in Example 2, a good positive image was obtained on a copper plate.

Example 4 An alternating copolymer of butadiene and maleic anhydride [composition ratio: butadiene/
Maleic anhydride = 50/50 (mole ratio)] was synthesized.

A photosensitive solution was prepared by dissolving 5 g of the alternating copolymer and 0.15 g of 2,6-bis(p-azidobenzal)-4-methylcyclohexanone in 15 ml of methyl ethyl ketone.

A resist layer was formed on an aluminum plate, and after exposure, it was developed using a 0.5% aqueous sodium hydroxide solution.

Next, the image was printed on an aluminum plate, and then etched with 5% hydrochloric acid water. Although the image had sufficient resolution, some side etching was observed.

Examples 5 to 12 A 50% by weight methyl ethyl ketone solution of each copolymer shown in Table 1 was prepared by polymerizing using methyl ethyl ketone as a solvent.

Add 20g of this solution to 2,6-bis(p-azidobenzal)
After adding 0.3 g of -4-methylcyclohexanone and stirring well to dissolve it, this solution was applied onto a copper-clad laminate using a spin coating device.

This was placed in a hot air dryer to remove the solvent to obtain a resist layer with a thickness of about 30 μm, which was then exposed through a negative image and developed using a 0.5% aqueous sodium hydroxide solution.

This material was washed with water, dried, and then treated with a 20% ferric chloride aqueous solution to etch the copper.

The results are shown in Table 1.

Example 13 In place of the photocrosslinking agent 2,6-bis(p-azidobenzal)cyclohexanone used in Example 1, the photosensitizer 1,4-
When the evaluation was carried out in the same manner as in Example 1 except that naphthoquinone was used, a positive image faithful to the original was obtained.

Further, etching was carried out in the same manner as in Example 1, but the resist film did not peel off at all and a good relief image was obtained.

Claims (1)

[Claims] 1(I) A conjugated diene hydrocarbon (A) and an α,β-ethylenically unsaturated carboxylic acid (B) are essential components, and a monoolefinic unsaturated compound (C) is added to this to A: 10 to 9.
A photosensitive material characterized by containing a copolymer containing 5 mol%, B: 5 to 90 mol%, and C: 0 to 85 mol%, and (■) a photosensitizer and/or a photocrosslinking agent. sexual composition.