JP2004157284A - Resist stripping liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist stripping liquid which has high stripping property with little corrosion of metal such as copper and does not etch an insulating material having a low dielectric constant. <P>SOLUTION: The resist stripping liquid contains: (a) a fluorine compound; (b) a divalent alcohol compound having an ether bond in the molecule; (c) an organic acid compound; and (d) water. After a resist pattern is formed on a substrate where a metal film and/or an insulating film is layered, the substrate is etched to transfer the pattern to the metal film and/or the insulating film. Then, the substrate obtained after ashing the resist pattern is brought into contact with the stripping liquid to strip the resist. <P>COPYRIGHT: (C)2004,JPO

Description

【００２５】
以上の結果から、有機酸化合物と、水溶性有機溶剤として分子内にエーテル結合を有する２価のアルコール化合物とを含有する本発明の剥離液（組成物記号１〜５）は、剥離性に優れている上、銅腐食耐性とエッチング耐性にも優れることが判る。一方、水溶性有機溶剤が、分子内にエーテル結合を有しているもののアルコール性水酸基を１つしか有さないエチレングリコールモノメチルエーテルやジエチレングリコールモノメチルエーテルしか含有しない剥離液（組成物記号Ａ、Ｂ）では、剥離性に優れているものの、銅腐食耐性やエッチング耐性が十分ではないことが判り、水溶性有機溶剤として分子内にエーテル結合を有する２価のアルコール化合物を含有するモノの有機酸化合物を含有しない剥離液（組成物記号Ｃ）では剥離性に劣ることが判る。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resist stripping solution used for manufacturing semiconductor devices such as ICs and LSIs and liquid crystal panel devices, and more particularly to a resist stripping solution used for removing residues generated after etching or ashing (ashing). .
[0002]
[Prior art]
One of the methods for manufacturing semiconductor devices such as ICs and LSIs and liquid crystal panel devices is to laminate a resist film on a substrate on which a metal film or an insulating film is laminated, and then expose and develop through a mask pattern. After forming a resist pattern, using the resist pattern as a mask, etching the metal film or the insulating film laminated under the resist film, and transferring the pattern to the metal film or the insulating film. There is a method having a process of removing In order to remove the resist pattern, the resist is usually ashed.
An etching residue or an ashing residue made of an organic substance or an inorganic substance adheres to the metal film, the insulating film, and the like on which the pattern thus obtained is formed. In order to remove these residues, it is common to bring the resist pattern into contact with a stripping solution (stripping process) and, if necessary, with a rinsing solution containing water (rinsing process).
In such a process, copper is used for a metal film to be a wiring layer, and hydrogenated silsesquioxane, alkyl silsesquioxane, and a porous film of organic spin-on-glass (SOG) are used for an insulating film. And organic polymers such as polyarylene ether; low dielectric constant insulating materials such as chemical vapor deposited films formed by vapor phase growth such as fluorine-containing silicon oxide films and carbon-containing silicon oxide films.
[0003]
Therefore, the stripping solution used for removing the residue generated by the above-mentioned etching or ashing has little corrosion to metals (mainly copper) (copper corrosion resistance) and little etching to low dielectric constant insulating materials ( Etching resistance).
On the other hand, with higher integration of LSIs, the above-mentioned etching and ashing conditions become more severe, and residues that are more difficult to remove tend to be formed. With a conventionally known organic amine-based stripping solution, it has been difficult to remove such a residue that is more difficult to remove while suppressing etching of the low dielectric constant insulating material. Accordingly, a stripper containing a fluorine compound has been proposed as a stripper having a high ability to remove resist residues. Examples of the stripping solution containing a fluorine compound include a resist stripping solution having a pH of 5 to 8 containing a salt of hydrofluoric acid and a base not containing a metal ion, and a water-soluble organic solvent (Japanese Patent Laid-Open No. 9-197681). Japanese Patent Application Laid-Open No. 11-67632, a fluorine compound, a water-soluble organic solvent, and a cleaning agent for a semiconductor device each containing a specific amount of water (Japanese Patent Laid-Open No. 11-67632), a fluorine compound, an ether solvent, and a peeling each containing a specific amount of water. Liquid compositions (Japanese Patent Application Laid-Open No. 2001-100436) and the like are known.
[0004]
However, with these stripping solutions, it has not been possible to satisfy the demand for a stripping solution that balances higher stripping ability, corrosion resistance and etching resistance at a high level.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-197681 [Patent Document 2]
JP-A-11-67632 [Patent Document 3]
JP 2001-100436 A
[Problems to be solved by the invention]
Under such circumstances, the present inventors have conducted intensive studies to obtain a resist stripping solution having a high stripping property, which has low corrosion to metal and does not etch a low dielectric constant insulating material, and as a result, contains a fluorine compound. The present inventors have found that when a specific water-soluble organic solvent and an organic acid compound are added in combination to a stripping solution, this object is achieved, and that the residue can be removed in a short time, thus completing the present invention.
[0007]
[Means for Solving the Problems]
Thus, according to the present invention, a resist stripping solution containing (a) a fluorine compound, (b) a dihydric alcohol compound having an ether bond in the molecule, (c) an organic acid compound, and (d) water is provided. Provided, also, after forming a resist pattern on a substrate on which a metal film and an insulating film are stacked, etching to transfer the pattern to the insulating film, and then a substrate obtained by ashing the resist pattern and And a resist stripping method, wherein the resist stripping solution is brought into contact with the resist stripping solution.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The stripping solution of the present invention comprises the components described below. Further, the pH of the stripping solution of the present invention is not particularly limited, but is preferably 2 to 6, preferably 2.5 to 5, since better stripping properties are exhibited on the acidic side.
The fluorine compound as the component (a) may be a compound containing a fluorine atom widely used as a stripping solution component. Examples thereof include ammonium fluoride, hydrofluoric acid, ammonium acid fluoride, and borofluoride. Examples thereof include ammonium, methylamine hydrofluoride, ethylamine hydrofluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, and alcoholamine hydrofluoride. More preferably, it is ammonium fluoride. These fluorine compounds may be used alone or in combination of two or more.
The amount of the fluorine compound to be used is generally 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the total amount of the stripping solution. If the concentration of the fluorine compound is too high, copper corrosion resistance and etching resistance tend to be poor.
[0009]
The dihydric alcohol compound having an ether bond in the molecule as the component (b) is a water-soluble organic solvent having one or more ether bonds and two alcoholic hydroxyl groups. Examples of such water-soluble organic solvents include dialkylene glycols such as diethylene glycol and dipropylene glycol; trialkylene glycols such as triethylene glycol and tripropylene glycol; 3-methoxy-1,2-propanediol, and 3-ethoxy-1. And glycerin derivatives (glycerin monoether) such as 2,2-propanediol, 3-allyloxy-1,2-propanediol, and 3-benzyloxy-1,2-propanediol. Among them, dialkylene glycol is particularly desirable from the viewpoint of rinsing properties and operability during the rinsing treatment. The dihydric alcohol compound having an ether bond in the molecule may be used alone or in combination of two or more.
The amount of the dihydric alcohol compound having an ether bond in the molecule is usually 30 to 90% by weight, preferably 35 to 85% by weight, and particularly preferably 40 to 80% by weight based on the total amount of the stripping solution. When a monohydric alcohol having an ether bond in the molecule (e) described later is used in combination, it is preferable to use the component (b) in a small amount (60% by weight or less).
[0010]
The organic acid compound as the component (c) may be any organic compound exhibiting acidity, and is particularly preferably an organic acid having a carboxyl group. Specifically, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, pivalic acid, 2-methylbutyric acid, 2,2-dimethylbutyric acid, 2-ethylbutyric acid, tert-butylbutyric acid, oxalic acid, malonic acid, methylmalon Acid, ethylmalonic acid, dimethylmalonic acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, 3-methyladipic acid, 1,2,3-propanetricarboxylic acid Acid, 1,2,3,4-butanetetracarboxylic acid, lactic acid, gluconic acid, tartaric acid, malic acid, glycolic acid, citric acid and the like. Formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, lactic acid, tartaric acid, malic acid, and citric acid are preferred because the pH of the stripping solution is easily adjusted to 3 to 5. The organic acid compounds may be used alone or in combination of two or more.
The amount of the organic acid compound to be used is generally 1 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the stripping solution. If the concentration of the organic acid compound is too high, the material having a low dielectric constant tends to be etched.
[0011]
The amount of water used as the component (d) is usually 5 to 50% by weight, preferably 10 to 40% by weight, based on the total amount of the stripping solution.
[0012]
When a monohydric alcohol compound having an ether bond in the molecule is contained as the component (e) in the stripping solution of the present invention, the viscosity of the stripping solution is reduced, and the operability is improved. The monohydric alcohol compound having an ether bond in the molecule is a water-soluble solvent having one or more ether bonds and one alcoholic hydroxyl group in the molecule, and specific examples thereof include ethylene glycol monoalkyl ether and diethylene glycol monoalkyl. Glycol monoalkyl ethers such as ether, triethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, and dipropylene glycol monoalkyl ether (the alkyl moiety is methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, t- Linear or branched alkyl having 1 to 6 carbon atoms such as butyl, isobutyl, n-pentyl, isopentyl, n-hexyl and isohexyl; the same applies hereinafter);
A linear or branched alkoxybenzyl alcohol having 1 to 6 carbon atoms in the alkyl moiety such as methoxybenzyl alcohol;
Aromatic ring-containing alkylene glycol ethers such as alkylene glycol benzyl ether, alkylene glycol phenyl ether, dialkylene glycol benzyl ether, dialkylene glycol phenyl ether, trialkylene glycol benzyl ether, and trialkylene glycol phenyl ether (the alkylene moiety is ethylene, propylene is there);
Cyclic ether alcohols such as glycidol, furfuryl alcohol, tetrahydrofurfuryl alcohol, tetrahydropyran-2-methanol, 2-methoxycyclohexanol, 5-ethyl-1,3-dioxane-5-methanol;
Is mentioned.
[0013]
Particularly, ethylene glycol monobenzyl ether, ethylene glycol cyclohexyl ether, propylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, and tetrahydrofurfuryl alcohol are preferred.
The monohydric alcohol compound having an ether bond in the molecule may be used alone or in combination of two or more. When the component (e) is added, its use amount is 5 to 55% by weight, preferably 10 to 45% by weight, based on the total amount of the stripping solution.
[0014]
Other components such as an anticorrosive agent can be added to the stripping solution of the present invention as needed.
As the anticorrosive, at least one selected from aromatic hydroxy compounds, carboxy group-containing compounds, ammonium salts of carboxy group-containing compounds, triazole compounds such as benzotriazole, and chelate compounds is preferably used.
The amount of the anticorrosive used is usually 0.1 to 10% by weight, particularly preferably 1 to 5% by weight, based on the total amount of the stripping solution.
[0015]
The stripping solution of the present invention is prepared by mixing the above-mentioned components, but the mixing order is not particularly limited. The mixing temperature is not particularly limited, but is usually 40 ° C. or lower, preferably 30 ° C. or lower, more preferably 25 ° C. or lower, from the viewpoint of preventing a change in composition.
The stripping solution of the present invention is excellent in corrosion resistance to a metal film, but is particularly effective for a copper film.
The stripping solution of the present invention is excellent in etching resistance to an insulating film made of a low dielectric constant insulating material, but has a remarkable effect particularly on an insulating film formed by chemical vapor deposition.
[0016]
The resist stripping method of the present invention is characterized in that a metal wiring substrate having a resist etching residue and / or an ashing residue on its surface is brought into contact with the resist stripping solution of the present invention. After the resist has been stripped in this manner, the rinsing solution can be removed by bringing the resist into contact with a stripping solution as necessary, further contacting with a rinsing solution containing water, and further contacting with water as needed.
A metal wiring substrate having a resist etching residue or an ashing residue, after forming a resist pattern on a substrate on which a metal film and an insulating film are laminated, etching and transferring the pattern to the insulating film, and then necessary It is obtained by ashing the resist pattern accordingly.
[0017]
The resist stripping method of the present invention will be described in detail below.
There is no particular limitation on a method of laminating a metal film and / or an insulating film on a substrate. For example, as a method of forming a metal film, aluminum, an aluminum alloy, titanium, tungsten, titanium tungsten, titanium nitride, tantalum, And a method of forming a metal layer of a metal such as tantalum oxide and copper by sputtering or plating.
Usually, an insulating film is formed on the metal film. As a method of forming an insulating film, a method of chemical vapor deposition of silicon oxide, silicon nitride, fluorine-containing silicon oxide, or carbon-containing silicon oxide on a substrate, a method of applying and drying a solution of an organic polymer on a substrate, A method in which a low dielectric constant material film formed as a film by a solution casting method using a roll coater or the like is heat-pressed to a substrate.
[0018]
A resist is applied to the substrate on which the metal film and / or the insulating film thus obtained are stacked, and dried to form a resist film. Thereafter, the resist film is irradiated (exposed) with actinic rays such as g-rays, i-rays, far ultraviolet rays, and electron beams through an appropriate mask pattern to form a latent image of the pattern on the resist film. The latent image is visualized (developed) by contact with a developer. Using the resist pattern thus obtained as a mask, the metal film and / or the insulating film is etched (dry-etched) with a chlorine-based etching gas, a fluorine-based etching gas, an ammonia-based etching gas, plasma, or the like. By contacting with plasma or the like (ashing), a substrate having a resist residue formed on the surface is obtained, and the substrate and the stripping solution of the present invention are brought into contact with each other to remove etching residues and ashing residues.
[0019]
There is no particular limitation on the method of bringing the stripping solution into contact with the substrate, such as a dipping method in which the substrate is immersed in the stripping solution, a spray method in which the stripping solution is sprayed on the substrate, and a liquid filling method in which the stripping solution is placed on the substrate. Method.
Both the environmental temperature and the temperature of the stripping solution during the stripping treatment can be arbitrarily selected.However, in consideration of the balance between securing the strippability and copper corrosion resistance, etching resistance, and suppressing the composition change of the stripping solution. , Usually 60 ° C or lower, preferably 10 to 50 ° C, more preferably 20 to 40 ° C.
[0020]
Note that examples of the substrate on which the metal film and / or the insulating film are stacked include a silicon wafer and a glass substrate. The substrate is made of amorphous silicon, polysilicon, chromium, chromium oxide, chromium alloy, magnetic material (eg, iron compound), ITO (indium-tin oxide), glass, gallium arsenide, gallium phosphide, indium phosphide, and the like. Can be
There is no particular limitation on the resist used, for example, a photosensitive resin composition containing an alkali-soluble resin, a photosensitive agent and a solvent, or a chemically amplified resist composition containing an alkali-soluble resin, an acid generator and a solvent For example, a resist composition used for manufacturing a general semiconductor element such as a product or a liquid crystal panel element can be used.
The developer for making the pattern in the latent image state visible is not particularly limited, and may be arbitrarily designed in accordance with the solubility of the resist used. For example, a 2.38% aqueous solution of tetramethylammonium hydroxide or the like may be used. A general developer such as xylene is used. The developing method may be a general method such as a paddle method, a dipping method, and a spray method.
The rinsing liquid is usually water, but if necessary, an organic solvent such as alcohol or glycol may be added. There is no particular limitation on the method of contacting the rinse solution, and the same method as the developing method can be employed.
[0021]
【Example】
The present invention will be described specifically with reference to the following examples, but the present invention is not limited to these examples. Parts and percentages in the examples are on a weight basis unless otherwise specified.
(Example)
On a silicon substrate on which a copper film is formed, an etch stopper layer (0.1 μm thick) composed of a SixNy film and an organic spion glass layer (insulating layer; 0.8 μm thick) are formed in this order, and then exposed to an alkali-soluble resin. A commercially available positive resist film containing the agent and the solvent was laminated. Thereafter, exposure was performed through a mask pattern to form a resist pattern on the substrate. Using this pattern as a mask, the organic SOG layer was etched and then ashed to remove about 90% of the resist film from above the substrate. After that, the etch stopper layer was etched. The substrate thus obtained is a substrate in which the copper surface is exposed and etching residues and ashing residues remain.
Next, the substrate was immersed in a stripper having the composition shown in Table 1 maintained at 23 ° C. for 3 minutes, rinsed with ultrapure water, and spin-dried.
The dried substrate is observed with a scanning electron microscope (SEM), and the state of removal of the residue remaining on the insulating layer or the copper surface serving as the hole pattern side wall (peelability) and the degree of corrosion of the Cu surface (copper Corrosion resistance).
[0022]
Separately, a 0.5 μm low-density SiOC film was formed on a silicon substrate, immersed in the stripping solution shown in Table 1, for 5, 10, 20 and 30 minutes, and the film thickness was measured by an optical film thickness meter. Was measured and each etching rate was calculated. The smaller the value, the higher the etching resistance.
These evaluation criteria are as follows. Table 1 shows the results.
[0023]
Peeling property ○: Removed △: Part of wafer has residue ×: Residue on entire surface of wafer and resistant to copper corrosion ○: No corrosion or Cu surface slightly deteriorated but corrosion Not at the level Δ: Cu surface is slightly depressed and etched. X: Cu is severely corroded. Etching resistance ○: 5 ° / min or less Δ: 5-10 ° / min ×: 10 ° / min or more ]
[Table 1]

[0025]
From the above results, the stripping solutions of the present invention (composition symbols 1 to 5) containing an organic acid compound and a dihydric alcohol compound having an ether bond in the molecule as a water-soluble organic solvent have excellent releasability. In addition, it can be seen that they have excellent copper corrosion resistance and etching resistance. On the other hand, a stripping solution containing only ethylene glycol monomethyl ether or diethylene glycol monomethyl ether in which the water-soluble organic solvent has an ether bond in the molecule but has only one alcoholic hydroxyl group (composition symbols A and B) Then, although excellent in peelability, it was found that copper corrosion resistance and etching resistance were not sufficient, and a mono-organic acid compound containing a dihydric alcohol compound having an ether bond in the molecule as a water-soluble organic solvent was used. It can be seen that the stripping solution not containing (composition symbol C) is inferior in stripping properties.

Claims (6)

A resist stripping solution containing (a) a fluorine compound, (b) a dihydric alcohol compound having an ether bond in a molecule, (c) an organic acid compound, and (d) water. 2. The resist stripping solution according to claim 1, wherein (b) the dihydric alcohol compound having an ether bond in the molecule is at least one selected from the group consisting of dialkylene glycols, trialkylene glycols, and glycerin derivatives. 3. The resist stripping solution according to claim 1, wherein (a) the fluorine compound is ammonium fluoride (NH ₄ F). The resist stripping solution according to any one of claims 1 to 3, wherein the pH is 2 to 6. The resist stripping solution according to any one of claims 1 to 4, further comprising (e) a monohydric alcohol compound having an ether bond in the molecule. A resist stripping method, comprising: contacting a metal wiring substrate having a resist etching residue and / or an ashing residue on its surface with the resist stripping solution according to any one of claims 1 to 5.