JP2008058625A - Photoresist stripping liquid, and substrate treatment method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoresist stripping liquid that can effectively remove a residue of a photoresist film and an etching residue on a substrate having a metal layer containing tantalum as at least a conductive metal film formed thereon, and to provide a substrate treatment method using the photoresist stripping liquid. <P>SOLUTION: The photoresist stripping liquid contains (A) a quaternary amine hydroxide of ≥0.5 mass% to ≤20 mass%, (B) a water-soluble organic solvent of ≥10 mass% to ≤80 mass%, and (C) water of ≥15 mass% to ≤80 mass%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photoresist stripping solution. In particular, the present invention relates to a photoresist stripping solution excellent in stripping performance, which is preferably used for manufacturing semiconductor elements such as IC and LSI, or liquid crystal panel elements, and a substrate processing method using the same.

When manufacturing a semiconductor element such as an IC or LSI, or a liquid crystal panel element, first, an insulating film such as a conductive metal film or a SiO ₂ film is formed on a substrate such as a silicon wafer or glass. Next, a photoresist is uniformly applied on the conductive metal film or the insulating film, and this is selectively exposed and developed to form a resist pattern. Then, the substrate is selectively dry-etched using this resist pattern as a mask to form a fine circuit. Thereafter, unnecessary residues of the photoresist film and etching residues are removed by washing with a stripping solution.
JP 09-152721 A JP-A-11-251214

  By the way, in dry etching processing of a conductive metal film or an insulating film, a chlorine-based gas or a fluorine-based gas is generally used as a dry etching gas. However, a photoresist film reacts with the dry etching gas and changes its quality. It is known that removal with a stripping solution becomes difficult.

  Therefore, in order to remove the residue of the photoresist film after dry etching processing, a stripping solution containing a water-soluble amine has been conventionally proposed (see Patent Documents 1 and 2). Since water is contained as an effective stripping component, the composition of the stripping solution may change due to continuous use for a long time, and the stripping performance may be deteriorated. Furthermore, in the case of a substrate on which a metal layer containing tantalum is formed as a conductive metal film, it is difficult to remove the residue of the photoresist film and the etching residue with a conventional stripping solution containing a water-soluble amine. It was.

  The present invention has been made in view of the above-described problems, and effectively removes photoresist film residues and etching residues on a substrate on which a metal layer containing tantalum as at least a conductive metal film is formed. An object of the present invention is to provide a photoresist stripping solution that can be removed and can be used continuously for a long time, and a substrate processing method using the same.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies focusing on the components contained in the photoresist stripping solution and the blending amount thereof. As a result, it has been found that the above-mentioned problems can be solved by containing a predetermined component in a predetermined blending amount, and the present invention has been completed. More specifically, the present invention provides the following.

  (A) quaternary amine hydroxide 0.5 wt% to 20 wt%, (b) water soluble organic solvent 10 wt% to 80 wt%, and (c) water 15 wt% to 80 wt%. A stripping solution for photoresist containing not more than 1% is provided.

  The present invention also provides the photoresist stripping solution used for stripping a photoresist on a substrate on which a metal layer containing tantalum is formed.

  Further, a photoresist film is formed on the substrate on which the metal layer containing tantalum is formed, the photoresist film is exposed and developed, and then the substrate is dry-etched, and the photoresist film residue is further formed. And a substrate processing method including a step of cleaning and removing an etching residue with the photoresist stripping solution.

  According to the present invention, the residue of the photoresist film and the etching residue on the substrate on which the metal layer containing tantalum as at least the conductive metal film is formed can be effectively removed.

  The photoresist stripping solution of the present invention (hereinafter also referred to as “stripping solution”) comprises (a) 0.5 to 20% by weight of a quaternary amine hydroxide, and (b) a water-soluble organic solvent. 10% by weight to 80% by weight and (c) 15 to 80% by weight of water. Hereinafter, each component will be described.

<(A) Quaternary amine hydroxide>
The stripping solution of the present invention contains a quaternary amine hydroxide (hereinafter also referred to as “component (a)”). The quaternary amine hydroxide includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, dimethyldiethylammonium hydroxide, trimethyl (2-hydroxyethyl). ) Use of quaternary ammonium hydroxides such as ammonium hydroxide and triethyl (2-hydroxyethyl) ammonium hydroxide, and bipyrrolidinium hydroxides such as spiro- [1,1 ′]-bipyrrolidinium hydroxide. it can. Among these, at least one selected from tetramethylammonium hydroxide, tetrapropylammonium hydroxide, and spiro- [1,1 ′]-bipyrrolidinium hydroxide is preferable from the viewpoint of improving peeling performance. (A) A component can be used 1 type or in combination of 2 or more types.

  (A) The compounding quantity of a component is 0.5 to 20 weight% in stripping solution. Furthermore, the lower limit is preferably 1% by weight or more, and the upper limit is preferably 10% by weight or less. (A) By making the compounding quantity of a component into the said range, the outstanding peeling performance can be obtained.

<(B) Water-soluble organic solvent>
The stripping solution of the present invention contains a water-soluble organic solvent (hereinafter also referred to as “component (b)”). The water-soluble organic solvent is not particularly limited as long as it is miscible with water and can dissolve other compounding components; sulfoxides such as dimethyl sulfoxide; dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) ) Sulfones such as sulfone and tetramethylene sulfone; Amides such as N, N-dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide and N, N-diethylacetamide; N-methylpyrrolidone Lactams such as N-ethylpyrrolidone, N-propylpyrrolidone, N-hydroxymethylpyrrolidone, N-hydroxyethylpyrrolidone; 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone 1,3-diisopropyl-2-imi Imidazolidinones such as zolidinone; polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl Glycol ethers such as ether and diethylene glycol monobutyl ether can be used.

  Among them, in the present invention, it is preferable to use a combination of glycol ethers and other water-soluble organic solvents.

  As the glycol ethers, at least one selected from diethylene glycol monoethyl ether and diethylene glycol monobutyl ether is preferable from the viewpoint of improving the peeling performance, and diethylene glycol monoethyl ether is particularly preferable because of excellent stability over time.

  In addition, as the other water-soluble organic solvent used in combination with the above glycol ethers, one or more selected from N-methylpyrrolidone, dimethyl sulfoxide, and propylene glycol are preferable from the viewpoint of improving peeling performance, and propylene glycol is particularly preferable. It is preferable from the viewpoint that the peeling performance can be maintained even under continuous use for a long time and that the liquid layer separation of the peeling liquid can be prevented.

  (B) The compounding quantity of a component is 10 to 80 weight% in stripping solution. Furthermore, the lower limit is preferably 20% by weight or more, and the upper limit is preferably 60% by weight or less. (B) By making the compounding quantity of a component into the said range, the outstanding peeling performance can be obtained.

  Furthermore, for the purpose of maintaining peeling performance under continuous use for a long time, one or more glycol ethers selected from diethylene glycol monoethyl ether and diethylene glycol monobutyl ether are contained in the peeling solution in an amount of 20 wt% to 60 wt%, and propylene It is preferable to use a mixed solvent in which glycol is 5 wt% or more and 20 wt% or less in the stripping solution.

<(C) Water>
The stripping solution of the present invention contains water (hereinafter also referred to as “component (c)”). (C) The compounding quantity of a component is 15 to 80 weight% in stripping solution. Furthermore, the lower limit is preferably 30% by weight or more, and the upper limit is preferably 70% by weight or less. (C) By making the compounding quantity of a component into the said range, the outstanding peeling performance can be obtained.

  The stripping solution of the present invention can exhibit the desired effect by containing the above components (a) to (c) in the above blending amounts, and in particular, the quaternary amine hydroxide as the component (a) is stripped. Due to the excellent performance, even a photoresist film residue and etching residue on a substrate on which a metal layer containing tantalum is formed can be effectively stripped at a relatively low processing temperature.

  If necessary, the stripping solution of the present invention may further contain an anticorrosive agent. Such anticorrosives can be classified into three types: anticorrosives having reducibility, anticorrosives having adsorbability, and anticorrosives having both reducibility and adsorbability.

The anticorrosive agent having the reducing, pyrocatechol, tert- butyl catechol, pyrogallol, aromatic hydroxy compounds such as gallic acid, xylitol, sorbitol, sugar alcohols such as butyl glucoside, with C n _(H 2 _{O) m} Examples thereof include sugar-based compounds such as glucose.

  Further, as the anticorrosive having the above adsorptivity, benzotriazole, 5,6-dimethylbenzotriazole, 1-hydroxybenzotriazole, 1-methylbenzotriazole, 1-aminobenzotriazole, 1-phenylbenzotriazole, 1-hydroxy Methylbenzotriazole, methyl 1-benzotriazolecarboxylate, 5-benzotriazolecarboxylic acid, 1-methoxy-benzotriazole, 1- (2,2-dihydroxyethyl) -benzotriazole, 1- (2,3-dihydroxypropyl) 2,2 ′-{[(4-Methyl-1H-benzotriazol-1-yl) methyl] imino} bisethano commercially available from Ciba Specialty Chemicals as benzotriazole or “Irgamet” series 2,2 ′-{[(5-methyl-1H-benzotriazol-1-yl) methyl] imino} bisethanol, 2,2 ′-{[(4-methyl-1H-benzotriazole-1- Il) methyl] imino} bisethane, or triazole compounds such as 2,2 ′-{[(4-methyl-1H-benzotriazol-1-yl) methyl] imino} bispropane.

  Examples of the anticorrosive having both the reducing property and the adsorptive property include mercapto group-containing compounds such as 1-thioglycerol and 2-mercaptoethanol.

  Among the anticorrosives, an anticorrosive containing a hydroxyl group or a mercapto group-containing compound is preferable, and at least one selected from an aromatic hydroxy compound and a mercapto group-containing compound is preferable from the viewpoint of anticorrosion performance. By selecting such an anticorrosive having a high anticorrosion performance, the desired anticorrosion performance can be obtained with a small amount of addition.

  When the anticorrosive agent is blended in the stripping solution of the present invention, the blending amount of the anticorrosive agent is 0.01 wt% or more and 10 wt% or less in the stripping solution. Furthermore, the lower limit is preferably 0.1% by weight or more, and the upper limit is preferably 5% by weight or less. By setting the blending amount of the anticorrosive to the above range, excellent anticorrosion performance can be obtained.

  The stripping solution of the present invention can be advantageously used for photoresists that can be developed with an alkaline aqueous solution, including negative and positive photoresists. Examples of such a photoresist include (i) a positive photoresist containing a naphthoquinone diazide compound and a novolac resin, (ii) a compound that generates an acid upon exposure, a compound that decomposes with an acid and increases the solubility in an alkaline aqueous solution, And a positive photoresist containing an alkali-soluble resin, (iii) a compound that generates an acid upon exposure, and a positive photoresist containing an alkali-soluble resin having a group that decomposes with an acid and increases the solubility in an aqueous alkali solution. And (iv) a negative photoresist containing a compound that generates an acid by light, a crosslinking agent, and an alkali-soluble resin, but is not limited thereto.

  The substrate processing method using the stripping solution of the present invention is as follows, for example. That is, a photoresist film is formed on a substrate on which a conductive metal film (particularly a metal layer containing tantalum) or an insulating film is formed, and this photoresist film is exposed and developed to form a resist pattern. Using this resist pattern as a mask, the substrate is dry-etched to form a fine circuit. Thereafter, unnecessary photoresist film residue and etching residue are removed by washing with the stripper of the present invention. After the peeling treatment, a rinsing treatment using pure water or a lower alcohol or the like conventionally used, and a drying treatment may be performed.

  The formation of the photoresist film, exposure, development, and dry etching are all conventional means and are not particularly limited.

  The stripping treatment using the stripping solution of the present invention is usually performed by an immersion method or a shower method. The peeling time may be a time sufficient for peeling and is not particularly limited, but is preferably shorter. The treatment temperature is preferably 30 to 70 ° C.

  In addition, the stripping solution of the present invention can maintain the stripping performance even under long-term continuous use by using a mixed solvent in which a specific water-soluble organic solvent is combined as the component (b) as described above. However, even when such a mixed solvent is not used, the stripping performance can be maintained by monitoring the component concentration of the stripping solution and appropriately adjusting the component concentration. For example, the amine concentration of the stripping solution is measured and managed by the electrical conductivity and the moisture content, and the concentration is adjusted so that it returns to the initial electrical conductivity when it falls below the predetermined electrical conductivity (when the degradation of the stripping performance starts to be observed). By adding an aqueous solution of quaternary amine hydroxide, the peeling performance can be maintained.

  Examples of the present invention will be described below. However, these examples are merely examples for suitably explaining the present invention, and do not limit the present invention.

(Examples 1 to 13, Comparative Examples 1 and 2)
[Removability of photoresist film]
A TFT photoresist TFR-H (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was patterned on a glass substrate on which a metal layer containing tantalum was formed, and post-baked at 150 ° C. for 90 seconds. Next, the substrate having the resist pattern was dry-etched to form a fine circuit. Thereafter, the substrate was immersed in 100 mL of a stripping solution having the composition shown in Table 1 below at 40 ° C. for 3 minutes to perform a stripping process. And the board | substrate after peeling processing was observed with the optical microscope and the scanning electron microscope (SEM), and the residual amount of the photoresist was evaluated by the following evaluation criteria. The stripping solution was continuously heated at 40 ° C., and after 24 hours, stripping was performed in the same manner as described above, and the residual amount of the photoresist was evaluated according to the following evaluation criteria. The results are shown in Table 1. In addition, the numerical value in the bracket | parenthesis in Table 1 represents weight%.

(Evaluation)
◎: No 99-95% residue ○: No 95-90% residue △: No 90-50% residue ×: 50% or more residue

[Separability of stripping solution]
A stripping solution having the composition shown in Table 1 below was prepared, and the separability of the stripping solution was visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 1.

(Evaluation)
○: No separation ×: With separation

ＴＭＡＨ：テトラメチルアンモニウムヒドロキシド
ＴＰＡＨ：テトラプロピルアンモニウムヒドロキシド
ＳＢＰＨ：スピロ−［１，１’］−ビピリジニウムヒドロキシド
ＭＥＡ：モノエタノールアミン
ＭＩＰＡ：モノイソプロパノールアミン
ＥＤＧ：ジエチレングリコールモノエチルエーテル
ＢＤＧ：ジエチレングリコールモノブチルエーテル
ＮＭＰ：Ｎ−メチルピロリドン
ＰＧ：プロピレングリコール
ＭＰ：１−チオグリセロール
Ｘｌｙ：キシリトール

TMAH: tetramethylammonium hydroxide TPAH: tetrapropylammonium hydroxide SBPH: spiro- [1,1 ′]-bipyridinium hydroxide MEA: monoethanolamine MIPA: monoisopropanolamine EDG: diethylene glycol monoethyl ether BDG: diethylene glycol monobutyl ether NMP : N-methylpyrrolidone PG: Propylene glycol MP: 1-thioglycerol Xly: Xylitol

From the results in Table 1, it was confirmed that the stripping solutions of Examples 1 to 13 exhibited excellent stripping performance even at a relatively low processing temperature of 40 ° C. Further, as can be seen by comparing Examples 1 to 4, 6 to 8 and Examples 5 and 9 to 13, diethylene glycol monoethyl ether or a mixed solvent of diethylene glycol monobutyl ether and propylene glycol is used as component (b). In the stripping solutions of Examples 1-4 and 6-8, the stripping performance was maintained even after 24 hours. On the other hand, the stripping solutions of Comparative Examples 1 and 2, which contained a water-soluble amine instead of a quaternary amine hydroxide, were inferior to the stripping solutions of Examples 1 to 13 in stripping performance.

Claims (7)

  (A) quaternary amine hydroxide 0.5 wt% to 20 wt%, (b) water soluble organic solvent 10 wt% to 80 wt%, and (c) water 15 wt% to 80 wt%. A stripping solution for photoresists containing at most%.   The photoresist stripping solution according to claim 1, further comprising (d) an anticorrosive agent in an amount of 0.01 wt% to 10 wt%.   The component (a) is at least one selected from tetramethylammonium hydroxide, tetrapropylammonium hydroxide, and spiro- [1,1 ′]-bipyrrolidinium hydroxide. Stripping solution for photoresist.   The component (b) is one or more glycol ethers selected from diethylene glycol monoethyl ether and diethylene glycol monobutyl ether, and one or more water-soluble organic solvents selected from N-methylpyrrolidone, dimethyl sulfoxide, and propylene glycol; The stripping solution for photoresists according to any one of claims 1 to 3, which is a mixed solvent.   The component (b) contains at least one glycol ether selected from diethylene glycol monoethyl ether and diethylene glycol monobutyl ether in a stripping solution of 20 wt% to 60 wt%, and propylene glycol in a stripping solution of 5 wt% to 20 wt%. The stripping solution for photoresists according to any one of claims 1 to 4, which is a mixed solvent having a weight percent or less.   6. The photoresist stripping solution according to claim 1, which is used for stripping a photoresist on a substrate on which a metal layer containing tantalum is formed. A photoresist film is formed on a substrate on which a metal layer containing tantalum is formed, the photoresist film is exposed and developed, and then the substrate is dry-etched, and the photoresist film residue and etching are performed. A method for treating a substrate, comprising a step of washing and removing the residue with the photoresist stripping solution according to claim 1.