JP2003241400A - Removing solution and method for removing resist using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a removing solution which does not corrode metals, can inhibit etching of a silicon-containing film of SiO<SB>2</SB>, Si<SB>x</SB>N<SB>y</SB>or the like formed on the surface of a substrate on a practical level, can remove resist residue on a substrate in a short time and is excellent in pH stability during use in a warmed state. <P>SOLUTION: The removing solution comprises (a) a fluorine compound such as ammonium fluoride, (b) a water-soluble organic solvent, (c) a buffer having its buffering pH region in a region of ≥pH 5, such as a good buffer, and (d) water. The removing solution may further comprises (e) ammonia water or a basic compound such as alcohol amines, hydroxylamines, polyalkylene polyamines, piperazines or morpholines. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping solution used for removing a resist pattern in the production of a semiconductor element such as an IC or an LSI or a liquid crystal panel element and a residue generated by subsequent etching, and a resist stripping solution using the stripping solution. Regarding the method.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device such as an IC or an LSI or a liquid crystal panel device, a resist composition is used to form a resist pattern on a substrate on which a wiring layer or an insulating layer is formed. The pattern is transferred to the underlying wiring layer or insulating layer by etching using the mask.
After that, the unnecessary resist pattern and etching residue are removed. In order to more efficiently remove the resist pattern and the like in this removal step, it is also considered to ash (ash) the resist pattern on the substrate after etching with oxygen plasma or the like. After such an ashing process, an ashing residue is generated on the substrate in addition to the unnecessary resist pattern and etching residue.
As a method for removing these resist residues, a method is known in which a stripping solution is brought into contact with a substrate on which a resist pattern is formed (peeling treatment step), and then the substrate is rinsed with a water rinse solution (rinsing treatment step). ing.

In recent years, in order to shorten the time of the stripping treatment step and the rinsing treatment step and improve the productivity, a strong resist stripping solution containing a fluorine compound has been proposed (Japanese Patent Laid-Open No. 7-201794). Japanese Patent Laid-Open No. 9-1976
No. 81, JP-A No. 11-67632, etc.). Although such a resist stripping solution certainly has good strippability, it has a problem of corroding metal wiring when used for a metal wiring board.

[0004]

Further, as a result of the study by the present inventors, in addition to the problem of corroding a metal, a conventional stripping solution containing a fluorine-based compound has (1) formation on a multilayer wiring board. To etch a silicon-containing film such as a SiO ₂ film or a Si _x N _y film which will be an interlayer insulating layer or an etching stopper layer to be formed, (2) Corrosion of metal wiring or etching of a silicon-containing film during peeling processing When it occurs, it was found that in the subsequent rinsing process, the water rinse liquid deteriorates the corrosion of the metal wiring and the etching of the silicon-containing film.

By the way, in order to remove the resist residue in a shorter time, a stripping process under a heating condition is also being studied. When the conventional stripping solution containing a fluorine-based compound is used under a heating condition of 30 ° C. or higher, the inventors of the present invention have severely corroded the metal wiring and etched the silicon-containing film so much that it is not suitable for practical use. I confirmed.

The present inventors have found that the corrosion of metal wiring and SiO ₂
As a result of diligent studies to obtain a stripping solution in which a film or a silicon-containing film such as a Si _x N _y film is less etched, it was confirmed that such corrosion is caused by pH fluctuation. Furthermore, the present inventors have also confirmed that the silicon-containing film is heavily etched particularly when the pH of the stripping solution is acidic. Based on such knowledge, it is possible to suppress corrosion of metal wiring and etching of a silicon-containing film such as a SiO ₂ film or a Si _x N _y film even under heating conditions, and to remove a resist residue in a short time. As a result of extensive studies to obtain a resist stripping composition having excellent pH stability, it was found that a stripping solution containing a fluorine-based compound had a p
It was found that the above problem can be solved by adding a buffering agent capable of stabilizing H, and the present invention has been completed.

[0007]

Thus, according to the present invention, (a) a fluorine compound, (b) a water-soluble organic solvent,
A stripping solution containing (c) a buffer having a buffer pH range of pH 5 or more, and (d) water is provided, and after etching the substrate using the resist pattern formed on the substrate as a mask, the substrate and the A resist stripping method is provided, which comprises contacting with an inventive stripping solution.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The fluorine compound as the component (a) is an organic or inorganic compound in which fluorine atoms are ion-bonded, and specific examples thereof include hydrofluoric acid; ammonium fluoride, ammonium acid fluoride, ammonium borofluoride, tetramethyl fluoride. Ammonium fluorides such as ammonium salts; amine hydrogen fluoride salts such as methylamine hydrogen fluoride salt and ethylamine hydrogen fluoride salt; and the like. From the viewpoint of peelability and corrosion resistance, ammonium fluorides are preferable. Yes,
More preferably, it is ammonium fluoride. The fluorine compounds may be used alone or in combination of two or more.
The content of the fluorine compound in the stripping solution is 0.1 to 10% by weight, and preferably 0.1% by weight, from the viewpoint of ensuring good strippability.
It is 1 to 5% by weight.

The water-soluble organic solvent as the component (b) may be any organic solvent that is compatible with water. Specific examples of such a solvent include formamide, dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl. Amides such as 2-pyrrolidone; imidazolidines such as 1,3-dimethyl-2-dimethylimidazolidine; sulfoxides such as dimethyl sulfoxide; ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol Ether such as diethyl ether; and the like. Of these, amides are preferable in view of the resist residue (especially etching residue and ashing residue) removal performance and metal corrosion resistance.
-Dimethylacetamide, N-ethyl-2-pyrrolidone and the like are particularly desirable. The water-soluble organic solvent may be used alone or in combination of two or more kinds. The content of the water-soluble organic solvent in the stripper is usually 30 to 80% by weight, particularly preferably 40 to 70% by weight, from the viewpoint of ensuring good strippability.
Is.

The buffering agent as the component (c) has a buffering pH range (pH range) of pH 5 or more, preferably pH 5 to 1
There is no particular limitation as long as it is 1 or more preferably 5 to 9 as the buffering agent. From the viewpoint of exhibiting the effect of the present invention that suppresses the corrosion of metal wiring and the etching of a silicon-containing film, and from the viewpoint of not deteriorating the peeling performance, a preferable buffering agent is a zwitterionic structure generally used in biochemical applications. Good buffer agents that are commercially available as buffer agents having Specific examples of the Good's buffer include the following compounds.

N- (2-acetamido) -2-aminoethanesulfonic acid (ACES), N, N-bis (2-hydroxyethyl) -2-aminoethanesulfonic acid (BE
S), N-cyclohexyl-3-aminopropanesulfonic acid (CAPS), N-cyclohexyl-2-hydroxy-3-aminopropanesulfonic acid (CAPSO), N
-Cyclohexyl-2-aminoethanesulfonic acid (CH
ES), N-tris (hydroxymethyl) methyl-3-
Aminopropanesulfonic acid (TAPS), 2-hydroxy-N-tris (hydroxymethyl) methyl-3-aminopropanesulfonic acid (TATPSO), N-tris (hydroxymethyl) methyl-2-aminomethanesulfonic acid (TES), etc. Aminoalkanesulfonic acids; 3
-(4- (2-hydroxyethyl) -1-piperazinyl) propanesulfonic acid (EPPS), 2- (4- (2
-Hydroxyethyl) -1-piperazinyl) ethanesulfonic acid (HEPES), sodium 2- (4- (2-hydroxyethyl) -1-piperazinyl) ethanesulfonate (HEPES-Na), 2-hydroxy-3- (4 −
Hydroxyethyl) -1-piperazinyl) propanesulfonic acid monohydrate (HEPPSO), piperazine-1,4
-Piperazinyl alkane sulfonic acids such as bis (2-ethanesulfonic acid) (PIPES) and piperazine-1,4-bis (2-hydroxy-3-propanesulfonic acid) dihydrate (POPSO); 3- ( Hydroxyalkanesulfonic acids such as N, N-bis (2-hydroxyethyl) amino) -2-hydroxypropanesulfonic acid (DIPSO); 2-morpholinoethanesulfonic acid monohydrate (MES), 3-morpholinopropanesulfonic acid (MO
PS), morpholinoalkanesulfonic acids such as 2-hydroxy-3-morpholinopropanesulfonic acid (MOPSO); N, N-bis (2-hydroxyethyl) glycine (Bicine), N- (tris (hydroxymethyl) methyl) glycine Glycines such as (Tricine); N- (2-acetamido) iminodiacetic acid (AD
A) such as iminoacetic acids; bis (2-hydroxyethyl) iminotris (hydroxymethyl) methane (Bis
-Tris) and other hydroxymethylalkanes; 2-
Hydroxyalkanes such as amino-2-hydroxymethyl-1,3-dihydroxypropane; etc.

Of these, piperazinyl alkanesulfonic acids such as 2- (4- (2-hydroxylethyl) -1-piperazinyl) ethanesulfonic acid are preferred because of their high effect of suppressing the etching of the silicon-containing film; 3 -Morpholinopropanesulfonic acid, 2-hydroxyl-3-morpholinopropanesulfonic acid and other morpholinoalkanesulfonic acids; N- (2-acetamido) iminodiacetic acid and other iminoacetic acids; and the like are particularly preferable. The buffering agent which is the component (c) can be used alone or in combination of two or more kinds. The content of the buffering agent as the component (c) in the stripping solution is usually 0.1 to 20% by weight, preferably 0.5, from the viewpoint of the balance between metal corrosion inhibition, silicon-containing film etching inhibition and strippability. -15% by weight, more preferably 1-10
% By weight.

The content of water as the component (d) in the stripping solution is 50 to 10% by weight, preferably 40 to 20% by weight.

In the present invention, the addition of the basic compound (e) as an additional component makes it possible to further reduce the pH fluctuation range of the stripping solution. Examples of the basic compound as the component (e) include aqueous ammonia, alcohol amines, hydroxylamines, polyalkylene polyamines, piperazines, morpholines, and the like, among which ammonia water, alcohol amines, and morpholines are preferable.

Specific examples of alcohol amines include monoethanolamine, monopropanolamine, isopropanolamine, 2-amino-1-propanol and N.
-Methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine,
N, N-dibutylethanolamine, N-methylpropanolamine, N, N-dimethylpropanolamine,
Monoalcoholamines such as N, N-diethylpropanolamine, 2- (2-aminoethoxy) ethanol, N-methyldiethanolamine; dialcoholamines such as diethanolamine, dipropanolamine, diisopropanolamine; triethanolamine,
Examples include trialcoholamines such as tripropanolamine and triisopropanolamine, and among them, monoalcoholamines such as monoethanolamine and N-methylethanolamine are preferable.

Specific examples of hydroxylamines include:
Hydroxylamine, N-methylhydroxylamine,
Examples thereof include N, N-dimethylhydroxylamine.
Specific examples of the alkyleneamines include diethylenetriamine, triethylenetetraamine, propylenediamine, N-ethyl-ethylenediamine, N, N-diethylethylenediamine, N, N'-diethylethylenediamine, N, N, N ', N'-. Tetramethylethylenediamine, 1,4-butanediamine, 1,2-propanediamine, 1,3-propanediamine, 1,6-hexanediamine, diethylenetriamine, N, N, N ′, N ′,
N ", N" -pentamethyltriamine and the like can be mentioned.

Specific examples of piperazines include piperazine, N-methyl-piperazine, methyl-piperazine, hydroxylethylpiperazine, aminoethylpiperazine and the like. Specific examples of morpholines include morpholino ethanol and aminopropylmorpholine, and aminopropylmorpholine is particularly preferable. These basic compounds may be used alone or in combination of two or more. The content of the basic compound in the stripping solution is usually 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, from the viewpoints of maintaining strippability and pH stability.

In the present invention, an anticorrosive agent may be further added. The anticorrosive agent is not particularly limited as long as it is a water-soluble compound having anticorrosive properties against metals, but aromatic hydroxy compounds such as catechol, pyrogallol, anthranilic acid and gallic acid; benzoic acid, phthalic acid, phthalic anhydride, 1, Aromatic carboxy group-containing compounds such as 2,3-benzenetricarboxylic acid; benzotriazole, o-tolyltriazole, m-tolyltriazole, p-tolyltriazole, carboxybenzotriazole, 1-
At least one selected from triazole compounds such as hydroxybenzotriazole, nitrobenzotriazole, and dihydroxypropylbenzotriazole is preferably used. In the stripping solution, the content of the anticorrosive agent, from the viewpoint of balancing strippability maintenance and metal corrosion inhibition,
Usually 0.1 to 10% by weight, particularly preferably 1 to 5% by weight
Is.

The method for preparing the stripping solution of the present invention is prepared by mixing the above-mentioned respective components. The order of mixing is not particularly limited.

There is no particular limitation on the substrate used in the resist pattern removing method of the present invention, and examples thereof include those obtained by the following method. A metal layer such as a metal such as aluminum, aluminum alloy, titanium, and copper is formed on a substrate such as a silicon wafer by a method such as sputtering or plating. Alternatively, an insulating film such as silicon oxide or silicon nitride is formed. After coating a resist composition on this substrate and drying it to form a resist film, g-line, i-line,
A latent image of the pattern is formed on the resist film by using actinic radiation such as deep ultraviolet rays and electron beams. The latent image is visualized by developing with a developing solution, and the oxide film is dry-etched with a chlorine-based or fluorine-based etching gas, plasma or the like using this pattern as a mask to obtain a substrate having a resist pattern formed on the surface. .

There is no particular limitation on the composition used for obtaining the resist pattern. For example, a photosensitive resin composition containing an alkali-soluble resin, a photosensitizer and a solvent, or an alkali-soluble resin, an acid generator and a solvent. A resist composition used for manufacturing a general semiconductor device or a liquid crystal panel device, such as a chemically amplified resist composition containing a can be used. The developer for exposing the pattern in the latent image state is not particularly limited, and may be arbitrarily designed in accordance with the solubility of the resist pattern used, for example, 2.3.
A general developer such as 8% tetramethylammonium hydroxide aqueous solution or xylene can be used. The developing method may be a general method such as a paddle method, a dip method, or a spray method.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples, but the contents of the present invention are not limited thereto. Further, parts and% in the examples are by weight unless otherwise specified.

(Examples 1 to 5, Comparative Examples 1 and 2) Copper on the surface
As an etching stopper layer on the substrate on which the film is formed
All Si_xN _yFilm and organic SOG (Sp
in-on-glass) film in this order
A commercially available positive resist pattern is formed on the formed silicon-containing film.
After coating with a spin coater at 90 ° C for 90 seconds
Pre-baked to form a 1.07 μm thick resist film
It was Hole pattern with 0.5 μm diameter using i-line stepper
Was transferred to the resist film. Then at 110 ° C for 60 seconds
Bake (post-exposure bake), then 2.38%
23 ° C. with an aqueous solution of tramethylammonium hydroxide,
1 minute paddle development to form a positive pattern
It was Using this pattern as a mask, the organic SOG film is fluorine
Etching with a system gas, followed by oxygen plasma
The resist pattern is ashed with
The distant pattern was removed. Further Si_xN_yEtch film
The copper surface is exposed, and the inorganic and organic substances are
A substrate in which the mixed residue remained was obtained. Next 40 ° C
Stripping solution having the composition shown in Table 1 that has been left to heat for 4 hours
After peeling the substrate with a spray method using
It was washed with pure water and then spin-dried.

[0024]

[Table 1]

The symbols in Table 1 are as follows. DMAc: dimethylacetamide NMP: N-methyl-2-pyrrolidone MES: 3-morpholinoethanesulfonic acid (pH range: 5.5 to 7.9) MOPS: 3-morpholinopropanesulfonic acid (pH range: 6.5 to 7) .9) ADA: N- (2-acetamido) iminodiacetic acid (pH
Range: 5.8-7.4) HEPES: 2- [4- (2-hydroxyethyl) -1
-Piperazinyl] ethanesulfonic acid (pH range: 6.
8 to 8.2) HA: Hydroxylamine MEA: Monoethanolamine BZT: Bensotriazole

The following evaluations were performed on the obtained substrates. The corrosiveness of the metal wiring and the etching property of the silicon-containing film were evaluated by observing the dried substrate with an SEM (scanning electron microscope). The obtained results are shown in Table 2. (1) Peelability ◯: Removed Δ: There is a residue in a part of the wafer ×: There is a residue on the entire surface of the wafer (2) Corrosion of metal wiring ◯: Corrosion does not occur, or The copper surface is slightly deteriorated, but not at the level of corrosion Δ: The copper surface is slightly dented and corroded. X: Copper corrodes violently and copper disappears completely. (3) Etching property of silicon-containing film (Si _x N _y film) ◯: No etching occurred. Δ: Very slight etching was observed. X: There is a clear etching. (4) pH fluctuation The stripping solution was heated at 40 ° C for 4 hours, and the pH before and after the heating was measured.

[0027]

[Table 2]

From the above results, the stripping solution of the present invention containing a buffering agent having a pH range of 5 or more does not cause a pH change even by heating and does not corrode metals.
Moreover, it has been found that the etchability of the SiO ₂ or Si _x N _y film can be suppressed to a practical level, and the residue on the substrate can be removed in a short time.

[0029]

EFFECTS OF THE INVENTION According to the present invention, a stripping solution that is less likely to cause metal corrosion and etching of a silicon-containing film can be obtained. Since the stripping solution of the present invention does not fluctuate in pH, stable stripping performance is obtained even in the production process, and quality control is facilitated.

Claims (8)

[Claims] 1. A stripping solution containing (a) a fluorine compound, (b) a water-soluble organic solvent, (c) a buffer having a buffer pH range of pH 5 or more, and (d) water. 2. The stripping solution according to claim 1, wherein (c) the buffer having a buffer pH range of pH 5 or more is a Good's buffer. 3. The stripper according to claim 1, further comprising (e) a basic compound. 4. (c) Good buffer is piperazinyl alkane sulfonic acid, morpholino alkane sulfonic acid,
Alternatively, the stripping solution according to claim 2, which is an iminoacetic acid. 5. The stripper according to claim 1, wherein the component (a) is ammonium fluoride. 6. The stripping solution according to claim 1, which has a pH of 6 to 10. 7. The method according to claim 1, wherein the substrate is etched using the resist pattern formed on the substrate as a mask.
7. A resist stripping method, which comprises contacting the stripping liquid according to any one of 6 above. 8. The substrate is etched using the resist pattern formed on the substrate as a mask, the resist pattern on the substrate is ashed, and then the stripping solution according to claim 1 is used. The resist stripping method according to claim 7, wherein the resist stripping is carried out.