JPH04361265A - Peeling liquid - Google Patents

Abstract

PURPOSE:To obtain a peeling liquid having excellent permeating property to a resist film and giving a rapid peeling rate and excellent permeation property even to a small-diameter through hole by incorporating an org. acid, a specified compd. and water of each specified amt. into the peeling liquid. CONSTITUTION:The peeling liquid contains 0.5-15wt.% of org. acid, 0.5-10wt.% of compd. expressed by formula I, and 75-99wt.% of water. In formula I, R is a hydrogen atom or lower alkyl group. The org. acid is preferably acetic acid, lactic acid, or hydroxyacetic acid. The compd. of formula I is preferably benzyl alcohol. This liquid is suitable to remove an etching resist pattern film after the etching treatment which is formed by the irradiation of active ray on a photosensitive compsn. of acid developing type and developing.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a stripping solution for etching resist films, and more specifically, the present invention relates to a stripping solution for etching resist films, and more particularly, it relates to an etching resist pattern film that is formed by irradiating an acid-developable photosensitive composition with actinic rays and then developing it. The present invention relates to a stripping solution suitable for use in removing after an etching process.

0002

[Prior art and its problems] After imagewise irradiation with actinic rays, development is performed with a developer to form a resist pattern film that is resistant to plating solutions and etching solutions (hereinafter sometimes referred to as etching resistance). Photoresists that can be used are often used as resists in the production of printed wiring boards and metal punched products.

Currently, as acid-developable photoresists, negative etching resists whose unexposed areas are removed by treatment with an acid aqueous solution (development treatment) are often used.

The thickness of a resist film formed using a photoresist is usually 5 to 70 μm, and after being used as a resist, it is usually removed from the surface of a substrate such as a printed wiring board substrate or a metal plate. be.

[0005] Peeling and removal of an acid-developable resist film from a substrate surface is usually carried out using a dilute aqueous solution of a monocarboxylic acid such as acetic acid, lactic acid, or hydroxyacetic acid. Peeling and removal of a resist film using such a stripping solution generally involves the following steps:
A method of immersing a substrate with a resist film in a stripping solution; A method of spraying a stripping solution onto a substrate with a resist film; A method of immersing a substrate with a resist film in a stripping solution and shaking or applying ultrasonic waves. This is done by various methods.

[0006] In recent years, electrodeposition type photosensitive etching resists have been developed and are attracting attention as a technology highly adaptable to fine patterning. In particular, when the substrate has through holes, an electrodeposition type etching resist is said to be preferable because of its high reliability in concealing the inside of the through holes. However, as the through holes become smaller, it becomes more difficult to peel off the resist film inside the through holes after etching. This is a drawback.

[0007] Furthermore, when applying an etching resist to a metal plate for metal punching, in order to improve the etching resistance of the resist film, irradiation with actinic rays is often performed after development. With the conventional stripping solution as described above, it takes a long time to strip and remove, and problems such as surface corrosion of the substrate metal tend to occur.

Furthermore, although certain organic solvents are often used as stripping solutions, organic solvents are unfavorable in terms of safety and environmental hygiene.

[0009]

[Means for Solving the Problems] As a result of intensive studies in order to eliminate the above-mentioned drawbacks of conventional stripping solutions, the present inventors have discovered that a stripping solution consisting of an aqueous solution of an organic acid such as acetic acid, lactic acid, or hydroxyacetic acid can be used. When benzyl alcohol or its lower alkyl substituted product is further added to the solution, the permeability into the resist film is significantly improved, and the etching-resistant resist film can be easily peeled off in a short time. The present inventors have found that the resist film penetrates easily, the resist film inside the through hole can be easily peeled off, and there are few problems in terms of safety and environmental hygiene, and the present invention has been completed.

[0010] Thus, the present invention provides: (a) an organic acid;
0.5-15% by weight (b) Formula (I) below

[0011]

[Chemical 2]

[0012] In the formula, R represents a hydrogen atom or a lower alkyl group.

0.5-10% by weight (c) Water

The object of the present invention is to provide a stripping solution for etching resist film characterized by containing 75 to 99% by weight.

The stripping solution of the present invention has extremely excellent permeability into the resist film, and can strip and remove the resist film in a short time without causing problems such as surface corrosion of the substrate metal. Since it can easily penetrate through-holes and peel off the resist film inside the through-holes, it is possible to eliminate defects caused by resist film residues inside small-diameter through-holes.

The stripping solution of the present invention will be described in more detail below.

[0015] As the organic acid as the component (a), those similar to those used in conventional acid development type stripping solutions can be used, and for example, acetic acid, lactic acid, hydroxyacetic acid, etc. are preferably used. . These acids may be used alone or in combination of two or more.

The blending ratio of component (a) as described above is 0.5 to 15% by weight, preferably 1 to 10% by weight, more preferably 1 to 5% by weight, based on the weight of the stripper.
can be within the range of If the proportion of component (a) is less than 0.5% by weight, the effect of peeling off the resist film will be low, and if it exceeds 15% by weight, the metal surface of the substrate may be attacked.

(b) In the compound represented by the above formula (I) as a component, the "lower alkyl group" which is a possible substituent on the benzene ring includes a linear or branched chain having 1 to 1 carbon atoms. 6, preferably 1 to 4 alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, and the like. Furthermore, the substitution site of the lower alkyl group is not particularly limited, but the 4-position is generally preferred.

However, the compound of formula (I) is
For example, benzyl alcohol, 4-methylbenzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 2-ethylbenzyl alcohol, 4-methylbenzyl alcohol,
Examples include -ethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 4-n-butylbenzyl alcohol, and among these, benzyl alcohol is particularly preferred because of its ease of availability.

The blending ratio of these components (b) may be within the range of 0.5 to 10% by weight, preferably 1 to 8% by weight, and more preferably 1 to 5% by weight based on the weight of the stripping solution. can. The blending ratio of the compound of formula (I) is 0.5% by weight
If the amount is less than 10% by weight, the effect of increasing the permeability of the stripper to the resist film or the peeling speed as intended by the present invention cannot be sufficiently obtained. However, it is not very desirable from the viewpoint of waste liquid treatment after use.

Water [component (c)] as a solvent for dissolving the components (a) and (b) described above does not need to be a special one, and can be used in conventional stripping solutions. You can use whatever you have in the same way. The blending ratio thereof can be within the range of 75 to 99% by weight, preferably 82 to 98% by weight, and more preferably 90 to 98% by weight based on the weight of the stripping solution.

The stripping solution of the present invention has the above-mentioned (a),
(b) and (c), but in some cases, (poly)alkylene glycol ethers such as ethylene glycol ethers, propylene glycol ethers, diethylene glycol ethers, dipropylene glycol ethers, etc. may be incorporated in small amounts, for example, up to 0.5% by weight based on the weight of the stripping solution.

The resist film that can be peeled off using the stripping solution of the present invention is an acid-developable photoresist, such as a negative-tone cationic photoresist whose main component is an acrylic resin containing an ethylenically unsaturated group and a tertiary amino group. A resist film formed using an electrodeposited photoresist, a negative cationic electrodeposition photoresist whose main component is an unsaturated resin containing a quaternary ammonium base, and the film thickness is generally 1 to 100 μm.
It is appropriate that it falls within a certain range.

As a method for stripping and removing a resist film from a substrate using the stripping solution of the present invention, a method known per se can be used. For example, a method of simply immersing a substrate having a resist film in a stripping solution, a method of stripping Examples include a method of spraying a liquid onto a resist film, a method of immersing a substrate having a resist film in a stripping liquid, and shaking or applying ultrasonic waves.

[0024] The temperature of the stripping solution is not particularly limited and can be used at room temperature, but it is usually convenient to use it at a temperature of room temperature to about 60°C.

[0025]

EXAMPLES The present invention will now be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Note that parts and percentages are based on weight.

Resist production example 1 617 parts of n-butanol was placed in a 5 liter four-necked flask.
After heating to 10°C, 550 parts of methyl methacrylate,
A mixed solution of 100 parts of n-butyl acrylate, 350 parts of glycidyl methacrylate, and 30 parts of azobisisobutylnitrile is added dropwise over 3 hours. After the temperature was maintained at 110°C for 1 hour, a mixture of 50 parts of n-butanol and 5 parts of azobiswalleronitrile was added dropwise over 1 hour, and the temperature was maintained at 110°C for an additional 5 hours, resulting in a number average molecular weight of approximately 10,000.
0 acrylic resin was obtained. After adding 73 parts of diethylamine to this acrylic resin solution and keeping it at 110°C for 1 hour, 108 parts of acrylic acid and 0.6 parts of hydroquinone were added and kept at 110°C for another 4 hours, resulting in an amine value of 47.5.
A photocurable cationic resin solution having a degree of unsaturation of 1.24 mol/kg, a Tg point of 28° C., and a number average molecular weight of about 12.000 was obtained. The resin solid content was 62%.

Obtained photocurable cationic resin solution 174
After sufficiently neutralizing by adding 30 parts of acetic acid to 0 parts, 400 parts of isobutyl alcohol and 50 parts of photopolymerization initiator benzoin ethyl ether were added, and after thorough mixing, the solid content was reduced to 1.
Deionized water was added to give an electrodeposition coating bath of 0%.

Resist Production Example 2 Photocurable cationic resin solution 1740 of Resist Production Example 1
400 parts of ethyl acetate and 70 parts of benzoin ethyl ether, a photopolymerization initiator, were added to the mixture and thoroughly stirred and dissolved to obtain a resist solution.

Resist Production Example 3 40 parts of methyl methacrylate, consisting of 30 parts of glycidyl methacrylate, 5 parts of styrene, 24 parts of n-butyl methacrylate, 23 parts of methyl acrylate, 18 parts of dimethylaminoethyl methacrylate, and 5 parts of azobisisovaleronitrile, butyl A mixed solution consisting of 40 parts of acrylate, 20 parts of acrylic acid, and 2 parts of azobisisobutyronitrile was added dropwise over 3 hours into 90 parts of cellosolve maintained at 80° C. under a nitrogen gas atmosphere. After dropping, the mixture was aged for 1 hour, and a mixed solution consisting of 1 part of azobisdimethylvaleronitrile and 10 parts of cellosolve was added dropwise over 1 hour, and further aged for 5 hours to obtain an acrylic resin solution. Next, 15 parts of acrylic acid and 0.13 parts of hydroquinone were added to this solution, and the mixture was heated to 110 parts while blowing air.
The reaction was carried out at .degree. C. for 5 hours to obtain a photocurable resin solution (amine value: 56, degree of unsaturation: 1.83 mol/kg, Tg point: 20.degree. C., average molecular weight: about 15,000). Resin solid content 53.5%
Met.

Obtained photocurable cationic resin solution 215
A solution prepared by dissolving 10 parts of ethyl acetate and 1 part of a photosensitizer represented by the following formula (II) was added to the mixture and mixed well, and further 8 parts of di-tert-butyl peroxyisophthalate as a radical generator was added. A resist solution was obtained by thorough mixing and decomposition.

[0031]

[C3]

Sample Preparation Example 1 Using the electrodeposition coating bath of Resist Production Example 1, both sides were copper plated with copper plated through holes (thickness 1.6 mm, through hole diameter 0.3 mmφ) with an aspect ratio of 5.3. The substrate was used as a cathode, and a DC voltage of 80 V was applied for 90 seconds at a bath temperature of 25° C. to perform electrodeposition coating. The coating film was washed with water and dried at 70° C. for 10 minutes to obtain a smooth coating film with a thickness of 12 μm without stickiness. Then,
A photomask with transparent through-hole openings having a line/space pattern of 100 μm/100 μm was brought into close contact with the coated plate, and both sides were irradiated with 150 mJ/cm 2 using an ultra-high pressure mercury lamp. Next, set the unexposed area to 1.0
% lactic acid aqueous solution and development, and after washing with water, the copper foil was removed by etching with ferric chloride to prepare sample 1.

Sample Preparation Example 2 The liquid resist of Resist Production Example 2 was applied uniformly to both sides of a copper plate with a thickness of 500 μm to a dry film thickness of 15 μm, and then dried at 70° C. for 10 minutes to form a smooth coating. I got a face. Next, line/space = 100μm/10 on both painted surfaces
A Voith mask having a 0 μm pattern was placed in close contact with the film, and both sides were exposed to light at a dose of 75 mJ/cm 2 using an ultra-high pressure mercury lamp. After developing this under the same conditions as Sample Preparation Example 1,
Furthermore, without masks on both sides, 150m using ultra-high pressure mercury lamps.
It was irradiated at a rate of J/cm2. Then, a punched plate was obtained by etching with an NH4Cl/NH3 alkaline etching solution. This was designated as sample 2.

Sample Preparation Example 3 After applying the liquid resist of Resist Production Example 3 to a thickness of 15 μm on a 500 μm thick copper plate in exactly the same manner as in Sample Preparation Example 2, a polyvinyl alcohol aqueous solution with a solid content of 3% was further applied thereon. After coating to a dry film thickness of 3 μm and drying, a pattern of line/space = 100 μm/100 μm was drawn directly on both sides with an argon ion laser irradiation machine (λ = 488 nm) at an exposure dose of 10 mJ/cm2, and then sample preparation was performed. The processing after development was carried out in exactly the same manner as in Example 2 to obtain a punched plate. This was designated as sample 3.

[0035]

Example 1 Stripping solution 1 was prepared by dissolving 3.0 parts of lactic acid in 94.0 parts of deionized water, adding 3.0 parts of benzyl alcohol, and stirring and mixing. Sample 1 created in sample creation example 1
The above-mentioned stripping solution 1 was sprayed onto the etched through-hole plate at 45° C. for 90 seconds at a pressure of 3.0 kg/cm 2 , the state of stripping of the resist film was observed, and the odor at the time of spraying was examined. The results are shown in Table 2 below.

[0036]

Examples 2 to 8 In the same manner as in Example 1, the resist films of Samples 1 to 5 were removed according to the combinations shown in Table 2 using stripping solutions 2 to 5 prepared according to the formulations shown in Table 1. The results are shown in Table 2.

[0037]

[Comparative Examples 1 to 7] Stripping solution 6 prepared according to the formulation in Table 1
9 to 9, the resist films of Samples 1 to 3 were stripped in the same manner as in Example 1 according to the combinations in Table 2. Table 2 shows the results.
Shown below.

[0038]

[Table 1]

[0039]

[Table 2]

Claims (3)

[Claims] Claim 1: (a) Organic acid
0.5 to 15% by weight (b) A compound represented by the following formula (I) [Formula 1] where R represents a hydrogen atom or a lower alkyl group
0
．． 5-10% by weight
(c) water
A stripping solution for etching resist film, characterized in that it contains 75 to 99% by weight. 2. The stripping solution according to claim 1, wherein the organic acid is acetic acid, lactic acid or hydroxyacetic acid. 3. The stripping solution according to claim 1 or 2, wherein the compound of formula (I) is benzyl alcohol.