JP2002062668A - Method for removing photoresist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing a photoresist by which the remaining photoresist in the photolithographic process of forming a pattern on the metal face of an electronic material such as a lead frame, printed wiring board or the like can be removed in a short time without deforming the metal pattern. SOLUTION: The removing liquid used in the method consists of an aqueous solution containing a quaternary ammonium hydroxide, water-soluble amines, hydroxyl amines, and if necessary, a corrosion preventive agent for copper-based metals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a photoresist, and more particularly, to exposing and developing a photo-curable photoresist as an etching resist, further performing etching, and then removing the remaining photoresist. The present invention relates to a method of removing a photoresist to be removed.

[0002]

2. Description of the Related Art As a method of forming a metal surface pattern of a thin film precision material of an electronic material such as a printed circuit board or a lead frame, a photolithography method is used in which a photocurable photoresist is used, which is previously exposed, developed, and etched. The method is commonly used. It is necessary to remove the remaining photoresist from the metal surface after the etching, and an aqueous solution of sodium hydroxide, potassium hydroxide, or the like is generally used as the stripping solution. When the photoresist is stripped with an aqueous solution such as sodium hydroxide or potassium hydroxide, the cured photoresist is stripped from the metal surface in the form of a film, and the peeled film-shaped photoresist is formed on the surface of the metal pattern. Adheres,
There are remaining problems. In order to solve this problem, measures such as increasing the spray pressure at the time of peeling are taken, but secondary troubles such as deformation of the metal pattern caused by increasing the spray pressure occur. . In particular, in recent years, this problem has arisen as the pattern of metal surfaces is becoming finer and thinner. Further, there has been a problem that the photoresist that peels off in the form of a film is clogged in a peeling tank, a pipe, a nozzle, a pump, or the like, and maintenance is complicated.

[0003]

The present invention resides in a photolithography process when a pattern is formed on a metal surface of an electronic material such as a lead frame or a printed wiring board, which tends to be finely patterned and thinned. It is an object of the present invention to provide a method of removing a photoresist in which the photoresist can be removed in a short time, and the removed photoresist does not remain on the pattern surface and does not deform the metal pattern.

[0004]

The present invention provides, as a photoresist stripping solution, (1) a stripping solution which is an aqueous solution containing a quaternary ammonium hydroxide, a water-soluble amine and hydroxylamines; By using a stripping solution that is an aqueous solution containing a quaternary ammonium hydroxide, a water-soluble amine, hydroxylamine, and a copper-based metal anticorrosive, the photoresist can be stripped in a short time, and the stripped photoresist is deposited on the metal pattern. It has been found that maintenance can be facilitated without remaining in the metal pattern and without deforming the metal pattern. That is, the present invention provides a manufacturing technique for stably forming a fine pattern on a metal surface of an electronic material such as a lead frame and a printed wiring board.

The quaternary ammonium hydroxide used in the present invention has the following formula (1)

Embedded image (Where R ₁ is an alkyl group having 1 to 3 carbon atoms, R ₂
Represents an alkyl group having 1 to 3 or a hydroxy-substituted alkyl group having 1 to 3 carbon atoms. ). As the quaternary ammonium hydroxide represented by the above formula (1), specifically, tetramethylammonium hydroxide,
Examples include tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide, and triethyl (2-hydroxyethyl) ammonium hydroxide. The concentration of the quaternary ammonium hydroxide used in the present invention is:
When the content is 0.1 to 20% by weight in the total solution, and when the content is 0.1% by weight or less, the photoresist stripping rate is reduced, and when the content is 20% by weight or more, corrosion occurs to a metal material or a substrate. Such troubles occur.

The water-soluble amine used in the present invention includes alkylamine, alkanolamine, polyamine, cyclic amine and the like. Examples of the alkylamine include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-
Butylamine, isobutylamine, t-butylamine,
Pentylamine, 2-aminopentane, 3-aminopentane, 1-amino-2-methylbutane, 2-amino-2
-Methylbutane, 3-amino-2-methylbutane, 4-
Amino-2-methylbutane, hexylamine, 5-amino-2-methylpentane, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine Primary alkylamines such as heptadecylamine and octadecylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, di-sec-butylamine, di-t
-Butylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, methylethylamine, methylpropylamine, methylisopropylamine, methylbutylamine, methylisobutylamine, methyl-sec-
Butylamine, methyl-t-butylamine, methylamylamine, methylisoamylamine, ethylpropylamine, ethylisopropylamine, ethylbutylamine, ethylisobutylamine, ethyl-sec-butylamine, ethylamine, ethylisoamylamine, propylbutylamine, propylisobutylamine, etc. And tertiary alkylamines such as trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, dimethylethylamine, methyldiethylamine and methyldipropylamine.

Examples of the alkanolamine include ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butyethanolamine, diethanolamine, isopronolamine, N-methylisopropanolamine, and N-methylethanolamine.
Ethyl isopropanolamine, N-propyl isopropanolamine, 2-aminopropan-1-ol, N
-Methyl-2-amino-propan-1-ol, N-ethyl-2-amino-propan-1-ol, 1-aminepropan-3-ol, N-methyl-1-aminopropan-3-ol, N -Ethyl-1-aminopropane-3
-Ol, 1-aminobutan-2-ol, N-methyl-1-aminobutan-2-ol, N-ethyl-1-aminebutan-2-ol, 2-aminobutan-1-ol, N-methine-2-aminobutane -1-ol, N-
Ethyl-2-aminobutan-1-ol, 3-aminobutan-1-ol, N-methyl-3-aminobutan-1
-Ol, N-ethyl-3-aminobutan-1-ol, 1-aminobutan-4-ol, N-methyl-1-
Aminobutan-4-ol, N-ethyl-1-aminobutan-4-ol, 1-amino-2-methylpropane-
2-ol, 2-amino-2-methylpropan-1-ol, 1-aminopentan-4-ol, 2-amino-
4-methylpentan-1-ol, 2-aminohexan-1-ol, 3-aminoheptane-4-ol, 1-
Aminooctane-2-ol, 5-aminooctane-4
-Ol, 1-aminopropane-2,3-diol, 2
-Aminopropane-1,3-diol, tris (oxymethyl) aminomethane, 1,2-diaminopropane-3
-Ol, 1,3-diaminopropan-2-ol, 2
-(2-aminoethoxy) ethanol and the like.

As the polyamine, ethylenediamine,
Propylenediamine, trimethylenediamine, tetramethylenediamine, 1,3-diaminobutane, 2,3-diaminebutane, pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylene Diamine, N-methylethylenediamine, N, N-dimethylethylenediamine, trimethylethylenediamine, N
-Ethylethylenediamine, N, N-diethylethylenediamine, triethylethylenediamine, 1,2,3-
Examples include triaminopropane, tris (2-aminoethyl) amine, tetra (aminomethyl) methane, diethylenetriamine, triethylenetetramine, tetraethylpentamine, heptaethyleneoctamine, nonaethylenedecamine and the like.

Specific examples of the cyclic amine include pyrrole, 2-methylpyrrole, 3-methylpyrrole, 2-ethylpyrrole, 3-ethylpyrrole, 2,3-dimethylpyrrole, 2,4-dimethylpyrrole, and , 4-dimethylpyrrole, 2,3,4-trimethylpyrrole, 2,
3,5-trimethylpyrrole, 2-pyrroline, 3-pyrroline, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, 2-4-lepetidine, 2,6 −
Lupetidine, 3,5-lupetidine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6
-Methylpiperazine, morpholine and the like. Among the above-mentioned alkylamines, alkanolamines, polyamines and cyclic amines, ethanolamine, N-methylethanolamine, diethanolamine, isopronolamine, N-methylisopropanolamine, 2
-Aminopropan-1-ol, N-methyl-2-amino-propan-1-ol, 2- (2-aminoethoxy) ethanol, ethylenediamine, diethylenetriamine, propanediamine, morpholine and the like. The concentration of the water-soluble amine is 0.01 to 80% by weight, preferably 0.1 to 30% by weight in the total solution. 0.01
If the amount is less than 80% by weight, the removal rate of the photoresist decreases. If the amount is more than 80% by weight, problems such as corrosion of a material or a substrate occur, which is not preferable.

The hydroxylamines used in the present invention include hydroxylamine, N-methylhydroxylamine, N-ethylhydroxylamine, N, N-diethylhydroxylamine and the like. The concentration of the hydroxylamines is 0.1 to 20% by weight, preferably 0.5 to 10% by weight in the total solution. If the concentration of the hydroxylamines is 0.1% by weight or less, the peeling rate of the photoresist decreases, and if it is 20% by weight or more, problems such as corrosion of materials and substrates occur.

As the copper-based metal anticorrosive used in the present invention, azole compounds, azine compounds and the like can be mentioned. Among the azole compounds, as a diazole compound, imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-imidazole, 2-phenyl-4-
Methylimidazole, undecylimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole, pyrazole, N-methylpyrazole, 3-
Methylpyrazole, 4-methylpyrazole and the like can be mentioned. In the azole compound, as a triazole compound,
1,2,3-triazole, 1,2,4-triazole, 1-phenyl-1,2,3-triazole, 2-phenyl-1,2,3-triazole, 1-phenyl-
1,2,4-triazole, 3- (N-salicyloyl)
Amino-1,2,4-triazole, benzotriazole, 1-methyl-1H-benzotriazole, 2-methyl-2H-benzotriazole, tolyltriazole,
Tolyltriazole potassium salt, benzotriazole
2-methylimidazole adduct and the like. In the azole compound, as a tetrazole compound, tetrazole, phenyltetrazole, mercaptotetrazole,
[Bis (2-ethylhexyl) aminomethylene] tetrazole, [bis (n-butyl) aminomethylene] tetrazole, [bis (n-hexyl) aminomethylene] tetrazole, [bis (n-octyl) aminomethylene] tetrazole, and the like. Can be Among the azine compounds, 1,2,3-triazine, 2,4-triazine, 1,3,5-triazine, 1,3,5-triazine-2,4-dithiol monosodium, 6-dibutyl as triazine compounds Amino-1,3,5-triazine-2,4-dithiol monosodium, 6-diethylamino-1,
3,5-triazine-2,4-dithiol, 6-dimethylamino-1,3,5-triazine-2,4-dithiol, 6-methoxy-1,3,5-triazine-2,4-
Dithiol, 6-phenylamino-1,3,5-triazine-2,4-dithiol, 2-vinyl-4,6-dithymino-1,3,5-triazine and the like. As a copper-based metal anticorrosive, an azole compound is particularly preferable, and the concentration of the azole compound is 0.01 to 10% by weight in the whole solution.
Preferably it is 0.05 to 5% by weight. If the concentration of the azole compound is 0.01% by weight or less, the corrosion action on copper cannot be suppressed, and if it is 10% by weight or more, the corrosion suppression action on copper cannot be improved, which is not economically advantageous.

There is no particular limitation on the stripping method using the stripping solution of the present invention, and there is no particular limitation. Conventionally, a dipping method, a spraying method, a method of rocking and dipping in a stripping solution, and dipping and applying ultrasonic waves. For example, a commonly used peeling method such as a method of performing the peeling is used. The temperature at which the photoresist is stripped and removed using the stripping solution of the present invention is 10 to 80C, preferably 30 to 60C, but is not particularly limited.

The photoresist to be stripped and removed in the stripping method of the present invention is of a photo-curing type, and is of a type in which the resist at the last-cured portion is developed with an aqueous alkali solution. Examples of such an alkali-developing photoresist include casein, polyvinyl alcohol, a polyhydric acrylate having an acroyl group or a methacryloyl group, or a photopolymerization initiator such as a methacrylate compound, a stabilizer, a color former, an adhesion promoter, and a dye. Is used.

As a method of applying a photoresist to a metal surface, a liquid resist coating method such as roll coating or pin coating, an electrodeposition coating method, an electrostatic coating method, a dry film method, etc. can be applied.

As the metal substrate to be patterned,
Lead frame made of iron, nickel-iron alloy, copper, copper alloy, etc., copper-clad flexible printed wiring board of polyimide, polyester, etc. or fiber-reinforced epoxy copper-clad printed wiring board, shadow mask of iron, chrome, iron alloy, etc. It can be applied to electronic material parts such as photomasks, mesh screens such as filters and strainers, metal foils, metal plates for precision parts, glass substrates, ceramic substrates and the like. In pattern processing, a photoresist is stuck on the cleaned metal surface, and the required parts are exposed by irradiating ultraviolet rays etc. through the photomask of the pattern master to cure the resist, and then the final cured part is removed with a developer. I do.
The developer used at this time is generally 0.5 to 2%
An aqueous solution of sodium carbonate or the like is used. The exposed metal surface of the developer is etched by the etchant to form a pattern. Acid baths such as iron chloride, copper chloride, sulfuric acid and hydrogen peroxide are used as the corrosive liquid.

[0016]

The present invention will be described below in detail with reference to examples.

[0017]

Example 1 An epoxy double-sided copper-clad laminate having a substrate thickness of 0.6 mm and a copper foil thickness of 0.03 mm was washed and polished with a bub polisher equipped with a nylon brush containing alumina abrasive grains, and then washed with water and dried. Thus, a clean substrate was obtained. Alkaline phenomena dry film (Sunfort AQ manufactured by Asahi Kasei)
(2559, film thickness 0.025 mm) was thermocompression-bonded with a laminator to obtain a laminated substrate. As a circuit network formed on the laminate substrate, a line width of 0.025 mm,
0.05mm and 0.1mm line to 0.5mm
Arranged at intervals. It has a test pattern (L) for inspecting a signal line and a test pattern for inspecting a line interval obtained by inverting the test pattern. To obtain an exposed substrate. Then 1%
A test peeled substrate formed by spraying with sodium carbonate at 30 ° C. for 2 minutes and spray etching with a ferric chloride solution having a specific gravity of 1.25 at 50 ° C. for 40 minutes was obtained.
1% by weight of tetramethylammonium hydroxide (hereinafter abbreviated as TMAH), 8% by weight of monoethanolamine, 0.5% by weight of hydroxylamine, 0.1% by weight of 1-methyl-1H-benzotriazole, As a result of being immersed in a stripping solution in which the remainder was water at 40 ° C. for 60 seconds, the dry film was stripped in very small pieces. Note that no corrosion was observed in the surface state of copper.

[0018]

Examples 2 to 10 The test release substrates used in Example 1 were immersed in the release solution shown in Table 1 at 40 ° C., and the release time and release state were examined. The results are shown in Table 1. In addition,
The evaluation criteria for the corrosion state of copper are shown below. ◎: No corrosion was observed in the surface state of copper. ×: Pit-shaped corrosion was observed on the copper surface.

[0019]

Comparative Examples 1 to 8 The test release substrate used in Example 1 was immersed in a release solution shown in Table 2 at 40 ° C.
The peeled state was examined, and the results are shown in Table 2.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

By using the stripping solution of the present invention,
In the photolithography step of forming a pattern on a metal surface, when the remaining photoresist is peeled and removed, the shape of the photoresist to be peeled is controlled, and the photoresist can be peeled as a very strip-shaped photoresist without deforming the metal pattern.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H096 AA26 AA27 BA05 HA13 HA17 LA03 5E339 AD01 AD03 BC02 BE11 CC01 CD01 CE12 CE15 CF15 CG04 5F067 AA10 DA16

Claims (4)

[Claims] 1. A photo-curable photoresist is used as an etching resist, and a metal surface on which a pattern has been formed by previously exposing, developing and etching with an acidic etchant is obtained by the following formula (1). (Where R ₁ is an alkyl group having 1 to 3 carbon atoms, R ₂
Represents an alkyl group having 1 to 3 or a hydroxy-substituted alkyl group having 1 to 3 carbon atoms. A) a stripping solution comprising an aqueous solution containing a quaternary ammonium hydroxide, a water-soluble amine and hydroxylamines represented by the formula (1), wherein the cured photoresist is stripped and removed from the metal surface; Peeling method. 2. The method according to claim 1, wherein the water-soluble amine is an alkanolamine, an alkylamine, a polyamine or a cyclic amine. 3. The method according to claim 1, wherein the stripping solution further contains a copper-based metal corrosion inhibitor. 4. The method according to claim 3, wherein the copper-based metal corrosion inhibitor is an azole compound.