JPH0727222B2 - Stripping solution for photoresist - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photoresist stripping solution, and more particularly to a photoresist stripping solution suitable as a stripping solution for positive resists and negative resists.

[Conventional technology]

As one step of manufacturing semiconductors and integrated circuits, a photoresist is applied on an inorganic substrate, exposed, and developed to form a resist pattern, and then, after processing such as etching, the resist pattern is peeled from the substrate. There is a step of peeling using a liquid.

Examples of the resist used here include a negative photoresist containing a cyclized product such as natural rubber, polyisoprene, and polybutadiene as a main component, and a positive photoresist containing an alkali-soluble resin such as a novolac resin as a main component. .

Conventional stripping solutions usually contain cresol and chlorinated hydrocarbons, which are harmful to the environment and have drawbacks such as difficulty in treating the waste solutions.

Recently, as a stripping solution which does not have such a defect, for example, a mixture of N-alkyl-2-pyrrolidone and diethylene glycol monoalkyl ether disclosed in JP-A-60-26340 and JP-A-58-80638 are disclosed. Morpholine or a mixture of morpholine and N, N-dimethylformamide, as disclosed in JP-A-61-6827
2-pyrrolidone and N- (2-hydroxyethyl) -2-
Mixtures with pyrrolidone have been proposed. However, these stripping solutions have a positive resist stripping effect, but have a problem that they do not have a stripping effect on a negative resist. Therefore, both the positive resist and the negative resist are stripped. There is a demand for a stripping solution that can be easily processed with a waste solution and that has few environmental hygiene problems.

[Problems to be solved by the invention]

An object of the present invention is to provide a photoresist stripping solution that can strip both positive and negative resists, is easy to treat with a waste solution, and has few environmental hygiene problems.

[Means for solving problems]

The present invention has the general formula (I) (In the formula, R ¹ is an alkyl group having 1 to 3 carbon atoms, R ^{2 to} R ⁶ are the same or different, and are a hydroxyl group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms. Meaning) and / or general formula (II) (In the formula, R ⁷ is an alkyl group having 1 to ⁷ carbon atoms, R ^{8 to} R ¹¹ are the same or different, and are a hydroxyl group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms. Contained) means salicylic acid ester and alkylbenzene sulfonic acid (excluding tetrachlorofluoroethane).

In the phenyl ethers represented by the general formula (I) used in the present invention, as the alkyl group having 1 to 3 carbon atoms, which is represented by R ¹ in the formula, a methyl group, an ethyl group,
Examples of the propyl group and the like, as the alkyl group having 1 to 4 carbon atoms represented by R ^{2 to} R ⁶ , include a methyl group, an ethyl group, a propyl group,
Examples thereof include an isopropyl group, a butyl group and a t-butyl group, and examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group and a propoxy group.

Specific examples of these phenyl ethers include anisole, 2-methylanisole, 3-methylanisole, and 4
-Methylanisole, 2-ethylanisole, 3-ethylanisole, 4-ethylanisole, 2-butylanisole, 3-butylanisole, 4-butylanisole, 2,3-dimethylanisole, 2,4-dimethylanisole, 2, 5-dimethylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, 2,3,5-trimethylanisole, 2-hydroxyanisole, 3-hydroxyanisole, 4-hydroxyanisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 2-methyl-3-hydroxyanisole,
Examples include anisole such as 1,3-dihydroxy-2-methoxybenzene, 2,3-dihydroxyanisole, and 2,6-dihydroxyanisole, ethylphenyl ether, and propylphenyl ether. Among these compounds, anisole is preferable, and anisole is particularly preferable. These phenyl ethers may be used alone or in 2
You may use it in mixture of 2 or more types.

In the salicylic acid ester represented by the general formula (II) used in the present invention, the alkyl group having 1 to 7 carbon atoms, which is represented by R ^{7 in} the formula, includes a methyl group, an ethyl group, a propyl group and a butyl group. Group, pentyl group, hexyl group,
Isoamyl group, etc., having 1 to 4 carbon atoms, which means R ^{8 to} R ^11.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group and a butyl group, and examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group and a propoxy group.

Specific examples of these salicylates include methyl salicylate, ethyl salicylate, propyl salicylate, butyl salicylate, pentyl salicylate, hexyl salicylate, isoamyl salicylate, and 2-hydroxy-.
Methyl 3-methylbenzoate, methyl 2-hydroxy-3-ethylbenzoate, methyl 2-hydroxy-3-butylbenzoate, methyl 2-hydroxy-3,4-dimethylbenzoate, 2-hydroxy-3,4, Methyl 6-trimethylbenzoate, methyl 3,5-dihydroxybenzoate, methyl 2,4-dihydroxybenzoate, methyl 2,3,4-trihydroxybenzoate and the like, and among these compounds, methyl salicylate and Isoamyl salicylate is preferred. These salicylic acid esters may be used alone or in combination of two or more.

The usage ratio of phenyl ethers and / or salicylates to the total amount of the stripping solution is usually 1 to 99% by weight, preferably 1 to 90% by weight. If these amounts are less than 1% by weight, the resist stripping performance of the stripping solution is poor, while
Even if it exceeds 99% by weight, the peeling effect is not improved, and the peeling performance of the negative resist is deteriorated.

Further, the stripping solution of the present invention can further enhance the stripping effect on the resist by mixing an alkylbenzene sulfonic acid and, if necessary, an aromatic hydrocarbon having a flash point of 70 ° C. or higher and a boiling point of 150 ° C. or higher.

Examples of the alkylbenzenesulfonic acid used in the present invention include benzenesulfonic acid, toluenesulfonic acid,
Xylenesulfonic acid, ethylbenzenesulfonic acid, methylethylbenzenesulfonic acid, trimethylbenzenesulfonic acid, propylbenzenesulfonic acid, cumenesulfonic acid, hexylbenzenesulfonic acid, heptylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfone Acid, tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid and the like can be mentioned. Among these compounds, dodecylbenzenesulfonic acid is preferable in consideration of industrial availability. The amount used is usually 1 to 99% by weight, preferably 10 to 99% by weight, based on the total amount of the stripping solution.

As the aromatic hydrocarbon having a flash point of 70 ° C. or higher and a boiling point of 150 ° C. or higher used in the present invention, for example, naphthalene, methylnaphthalene, dimethylnaphthalene, tetralin, dodecylbenzene, didodecylbenzene, octylbenzene,
Examples include decylbenzene, isopropylnaphthalene, diisopropylnaphthalene and the like. Among these compounds, dodecylbenzene is preferable in consideration of industrial availability. The amount used is usually 80% by weight or less, preferably 70% by weight or less, based on the total amount of the stripping solution. If the amount of the aromatic hydrocarbon used exceeds 80% by weight, the stripping performance of the positive resist will deteriorate.

In the stripping solution of the present invention, as the solvent other than the above, for example, amides, sulfoxides, sulfones, amines, amino alcohols, ketones, ethylene glycols and their derivatives, diethylene glycols and their derivatives, triethylene glycols. And their derivatives, propylene glycols and their derivatives, lactams, morpholines, etc. could be mixed and used. However, tetrachlorodifluoroethane is excluded.

Further, a nonionic fluorine-based surfactant can be added to the stripping solution of the present invention. Examples of the nonionic fluorine-based surfactant include C ₉ F ₁₉ CONHC ₁₂ H ₂₅ , C ₈ F ₁₇ SO ₂ NH (C
₂ H ₄ O) ₆ H, C ₉ F ₁₇ O (Pluronic L-35) C ₉ F ₁₇ , C ₉ F ₁₇ O (Pluronic P-84) C ₉ F ₁₇ , C ₉ F ₁₇ (Tetronic-704) (C
₉ F ₁₇ ) ₂ [Pluronic L-35: Asahi Denka Kogyo KK, polyoxypropylene (50 wt%)-polyoxyethylene (50 wt%) block polymer, average molecular weight 1,900; Pluronic P-84: Asahi Denka Kogyo Co., Ltd., polyoxypropylene (50% by weight) -polyoxyethylene (50% by weight) block polymer, average molecular weight 4,200; Tetronic-704: Asahi Denka Kogyo KK, N, N, N ', N' -Tetrakis (polyoxypropylene-polyoxyethylene block polymer) ethylenediamine, polyoxyethylene content in the molecule 40% by weight, average molecular weight 5,000], etc., as well as Surflon S-382 and
SC-101 (manufactured by Asahi Glass Co., Ltd.), F-top EF-122B (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC-430 and FC-431 (manufactured by Sumitomo 3M Ltd.) can also be used.

These nonionic fluorosurfactants can be used alone or in combination of two or more. The use ratio thereof is usually 20% by weight or less, preferably 10% by weight or less in the stripping solution of the present invention.

To strip the resist using the stripping solution of the present invention,
The stripping solution may be heated to, for example, about 90 to 130 ° C., and the substrate having the resist to be stripped may be dipped therein.

After that, a rinsing step is generally performed to remove the stripping solution attached to the substrate. In this rinsing step, first, the substrate to which the stripping solution has adhered is immersed in a solvent for 0.5 to 3 minutes. The solvent is not particularly limited as long as it is a solvent that can easily dissolve the stripping solution, for example, fluorinated hydrocarbon such as 1,2-difluoro-1,1,2,2-tetrachloroethane. And chlorinated hydrocarbons such as trichlorethylene, and these solvents can be used in combination with hydrocarbons and alcohols which are liquid at room temperature such as isooctane and propyl alcohol.

Next, in order to replace the solvent with a solvent that dissolves in water,
For example, it is immersed in alcohols such as ethanol and isopropyl alcohol for 0.5 to 3 minutes, and further washed with water for 0.5 to 3 minutes.

The stripping solution of the present invention is a negative resist whose main component is a cyclized product such as natural rubber, polyisoprene, and polybutadiene.
A general resist such as a positive resist containing an alkali-soluble resin such as a novolac resin as a main component can be peeled off, waste liquid can be easily treated, environmental hygiene problems are small, and it is easy to use.

〔Example〕

 Hereinafter, examples of the present invention will be described in detail.

Examples 1 to 14 and Comparative Examples 1 to 4 A positive photoresist PFR3003A (manufactured by Japan Synthetic Rubber Co., Ltd.) containing a novolak resin as a main component was spin-coated on a silicon wafer to a dry film thickness of 1.2 μm, and then, Prebaking, exposure, development and rinsing were carried out in the usual manner. Then, heat treatment was performed at 130 ° C. for 30 minutes in a clean oven to form a positive resist pattern.

On the other hand, a negative photoresist CIR702 (manufactured by Japan Synthetic Rubber Co., Ltd.) containing cyclized polyisoprene as a main component was spin-coated on another wafer to a dry film thickness of 0.85 μm, and then prebaked by an ordinary method. Exposure, development and rinsing were performed, and heat treatment was performed in a clean oven at 150 ° C. for 30 minutes under a nitrogen stream to form a negative resist pattern.

Next, these positive resist and negative resist patterns were immersed in a stripping solution having the composition shown in Table 1 at a predetermined temperature shown in Table 2 for a predetermined time, and then 1,2-difluoro-1,1, 30 seconds with a mixed solvent of 2,2,2-tetrachloroethane and isooctane, then 30 seconds with isopropyl alcohol.
Rinsing was performed for 2 seconds, followed by washing with water and drying. The presence or absence of the residual resist pattern on this wafer was observed with an optical microscope of 50 to 400 times or by irradiating the wafer with monochromatic light, and the residual degree of the positive resist pattern and the negative resist pattern was examined. The results are shown in Table 2.

The peeled states (1 to 3) in Table 2 were judged according to the following criteria.

1: The resist pattern residue is entirely observed.

2: Some resist pattern residue is observed.

3: No resist pattern residue is observed.

EFFECTS OF THE INVENTION The stripping solution for photoresist of the present invention can completely remove both positive type resist and negative type resist, the waste liquid treatment is easy and there are few environmental hygiene problems. Therefore, the stripping solution of the present invention is useful as a stripping solution for resist in the field of photoresist application, for example, in the field of electronic parts such as semiconductors, lead frames and shadow masks for televisions, and in the field of etching metal, ceramics, glass and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 61-198237 (JP, A) JP 61-2152 (JP, A) JP 63-243941 (JP, A)

Claims (1)

[Claims] 1. A general formula (I) (In the formula, R ¹ is an alkyl group having 1 to 3 carbon atoms, R ^{2 to} R ⁶ are the same or different, and represent a hydroxyl group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 3 carbon atoms. Do)
And / or general formula (II) (In the formula, R ⁷ is an alkyl group having 1 to ⁷ carbon atoms, R ^{8 to} R ¹¹ are the same or different, and represent a hydroxyl group, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 3 carbon atoms. A photoresist stripping solution containing salicylic acid esters and alkylbenzene sulfonic acid (excluding tetrachlorodifluoroethane).