JP2017147416A - Cleaning solution for lithography and cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning solution for lithography excellent in a corrosion-inhibiting function against at least one metal selected from the group consisting of cobalt, copper and an alloy containing either metal, and a method of cleaning a substrate using the cleaning solution for lithography.SOLUTION: A cleaning solution for lithography contains a basic compound, water, and an imidazole compound represented by the following formula (1a).SELECTED DRAWING: None

Description

  The present invention relates to a lithography cleaning liquid and a method for cleaning a substrate using the lithography cleaning liquid.

  A semiconductor device is formed by laminating a metal wiring layer, a low dielectric layer, an insulating layer, etc. on a substrate such as a silicon wafer. Such a semiconductor device is etched using a resist pattern as a mask. The above layers are manufactured by lithography.

  Resist films, temporary laminated films (also referred to as sacrificial films) used in the above lithography method, and metal wiring layers and low dielectric layer-derived residues generated in the etching process do not interfere with the next process. It is removed using a cleaning solution so as not to hinder the semiconductor device.

  Conventionally, as a lithography cleaning liquid used in such a semiconductor device manufacturing process, a cleaning liquid mainly composed of a quaternary ammonium hydroxide has been proposed (see, for example, Patent Document 1). Lithographic cleaning liquids composed mainly of such quaternary ammonium compounds have significantly improved removal performance for various residues compared to previous cleaning liquids, and are excellent in corrosion inhibition for aluminum wiring. there were.

JP 2002-357908 A

  In recent years, with the increase in density and integration of semiconductor devices, a wiring formation method using a damascene method has been adopted. In such a wiring formation method, copper, a copper alloy, or the like is employed as a metal wiring material constituting the metal wiring layer of the semiconductor device. Cobalt is also used as a metal wiring material in semiconductor devices in the form of a simple substance or an alloy. These metals used as metal wiring materials have a problem that they are easily corroded by a cleaning liquid for lithography. Therefore, there is a demand for a lithographic cleaning solution that is less likely to corrode copper, cobalt, and their respective alloys during substrate cleaning.

  The present invention has been made in view of such conventional circumstances, and includes at least one metal selected from the group consisting of cobalt and copper and any alloy thereof (in the present specification, “easily corroded”). An object of the present invention is to provide a lithography cleaning liquid having an excellent corrosion-inhibiting function against a metal and a method for cleaning a substrate using the lithography cleaning liquid.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, it has been found that the above-mentioned problems can be solved by adding a specific imidazole compound to the cleaning liquid for lithography, and the present invention has been completed. Specifically, the present invention provides the following.

（式中、Ｒはそれぞれ独立に、水素原子、又は１価の有機基を表し、Ｒ^２は置換基を有してもよい芳香族基を表し、Ｒ^４はそれぞれ独立にハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホナト基、又は有機基を表し、ｎは０〜３の整数を表す。上記Ｒは他方のＲ又はＲ^２と結合して環状構造を形成してもよい。） The first aspect of the present invention is a cleaning liquid for lithography containing a basic compound, water, and an imidazole compound represented by the following formula (1a).

(In the formula, R each independently represents a hydrogen atom or a monovalent organic group, R ² represents an aromatic group which may have a substituent, and R ⁴ each independently represents a halogen atom, a hydroxyl group, A mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonate group, a phosphino group, a phosphinyl group, a phosphonate group, or an organic group, and n represents an integer of 0 to 3. The above R represents the other. And may be bonded to R or R ² to form a cyclic structure.)

  The second aspect of the present invention is a method for cleaning a substrate using the lithography cleaning liquid according to the first aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the cleaning liquid for lithography excellent in the corrosion suppression function with respect to a corrosive metal, and the method of cleaning a board | substrate using this cleaning liquid for lithography can be provided.

<Lithography cleaning solution>
The cleaning liquid of the present invention contains a basic compound, water, and an imidazole compound represented by the above formula (1a) (hereinafter sometimes abbreviated as “imidazole compound”). Such a cleaning liquid is suitable as a lithography cleaning liquid, and may be referred to as a “lithographic cleaning liquid” in this specification. Furthermore, such a cleaning liquid may contain a water-soluble organic solvent from the viewpoint of ensuring a cleaning function.

  The lithography cleaning liquid of this embodiment is suitably used for cleaning a substrate having a metal on its surface. The substrate having a metal on the surface means a substrate in which at least a part of the metal is exposed on the substrate surface. The metal is, for example, a metal formed as a metal wiring layer, a plug, or other metal structure on the substrate on which the semiconductor device is formed. Examples of the substrate include a substrate in which a semiconductor device is formed by laminating a metal wiring layer, a low dielectric layer, an insulating layer, etc. on a substrate such as a silicon wafer.

  Examples of the metal include easily corrosive metals, specifically, cobalt, copper, and alloys of any of these. The lithography cleaning liquid of this embodiment is suitably used for cleaning a substrate having at least one metal selected from the group consisting of cobalt, copper, and any of these alloys on the surface. Examples of the alloy of cobalt and copper include an alloy of at least one of cobalt and copper and at least one of other transition elements and typical elements (for example, phosphorus, boron, silicon, etc.), Specifically, phosphorus and / or boron containing alloys such as CoWPB, and silicides such as CoSi are exemplified.

  The lithography cleaning liquid of the present embodiment has an excellent corrosion inhibiting function for easily corrosive metals by containing the imidazole compound represented by the formula (1a). That is, the imidazole compound functions as a corrosion inhibitor or anticorrosive agent, particularly as a suitable corrosion inhibitor for easily corrosive metals. Therefore, even when the cleaning liquid for lithography of the present embodiment contacts the metal on the substrate surface during the cleaning of the substrate, corrosion of the metal is satisfactorily suppressed. Although its mechanism of action is not clear, it is considered that the imidazole compound and metal ions react to form a chemical conversion film on the surface of the metal, and that the chemical conversion film suppresses metal corrosion. It is done.

  Hereinafter, although each component of the cleaning liquid for lithography of this embodiment will be described in detail, commercially available products can be used as the above components other than the imidazole compound represented by the formula (1a) unless otherwise specified.

[Basic compounds]
The basic compound is not particularly limited as long as it has a cleaning function. A basic compound may be used independently and may be used in combination of 2 or more type.

  As the basic compound, for example, a quaternary ammonium hydroxide can be used. As the quaternary ammonium hydroxide, a compound represented by the following general formula (a1) is preferable.

In the general formula (a1), R ^{a1 to} R ^a4 are each independently an alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, or carbon. A hydroxyalkyl group having 1 to 16 atoms is shown.

  Among the compounds represented by the general formula (a1), tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide, methyl The group consisting of tributylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldiethylammonium hydroxide, benzyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, and (2-hydroxyethyl) trimethylammonium hydroxide It is particularly preferable that it is at least one selected from the viewpoint of availability. Furthermore, tetramethylammonium hydroxide and tetraethylammonium hydroxide are preferable because they have high solubility in residues remaining after etching treatment and high cleaning performance.

  Moreover, an alkanolamine can be used as a basic compound. Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine. N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine and the like.

  Moreover, as a basic compound, you may use together an inorganic base with a quaternary ammonium hydroxide, for example. As the inorganic base, alkali metal hydroxides such as potassium hydroxide, sodium hydroxide and rubidium hydroxide are preferable, and potassium hydroxide is more preferable.

  The content of the basic compound is preferably 0.05 to 10% by mass and more preferably 0.1 to 5% by mass with respect to the total amount of the cleaning liquid for lithography, with respect to the quaternary ammonium hydroxide. Preferably, about alkanolamine, it is preferable that it is 0.05-20 mass%, and it is more preferable that it is 0.1-10 mass%. By setting it as such content, it remains after an etching process, suppressing the corrosion of an easily corrosive metal, especially at least 1 type of metal selected from the group which consists of cobalt, copper, and these alloys. Residue can be effectively removed. In addition, when using an inorganic base together with a quaternary ammonium hydroxide, the content of the inorganic base is preferably 0.1 mass ppm to 1 mass% with respect to the total amount of the cleaning liquid for lithography, and preferably 1 mass ppm to 1 mass ppm. More preferably, it is 1000 ppm by mass. By setting it as such content, it remains after an etching process, suppressing the corrosion of at least 1 sort (s) of metal selected from the group which consists of an easily corrosive metal, especially cobalt, copper, and these alloys. Residues can be effectively removed.

[water]
As water, it is preferable to use pure water, deionized water, ion-exchanged water or the like.
The water content is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, still more preferably 20 to 50% by mass, and more preferably 25 to 25% by mass with respect to the total amount of the cleaning liquid for lithography. It is still more preferable that it is 40 mass%. By setting it as such content, it remains after an etching process, suppressing the corrosion of at least 1 sort (s) of metal selected from the group which consists of an easily corrosive metal, especially cobalt, copper, and these alloys. Residues can be effectively removed.

[Imidazole compound]
As the imidazole compound, an imidazole compound represented by the above formula (1a) is used.

In formula (1a), R is a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, and may be, for example, an alkyl group that may have a substituent, an aromatic group that may have a substituent, or the like. May have an ester bond or the like. The alkyl group may be, for example, the same as R ¹ and the like in the formula (1) described below, but the number of carbon atoms is preferably 1 to 40, more preferably 1 to 30, still more preferably 1 to 20, Is even more preferred. Examples of the substituent that the alkyl group may have may be the same as the substituent that the alkylene group that is R ³ in formula (1) described later may have. The aromatic group that may have a substituent is the same as R ² in formula (1) described later, and is preferably an aryl group, more preferably a phenyl group. The aromatic group which may have a substituent as R may be the same as or different from R ² . In the formula (1a), one R is preferably a hydrogen atom, one R is a hydrogen atom, and the other R has an alkyl group which may have a substituent or an aromatic which may have a substituent. A group is more preferable. In the formula (1a), R may be bonded to the other R or R ² to form a cyclic structure. For example, when at least one R is an alkyl group which may have a substituent, R May be bonded to the other R or R ² to form a cyclic structure.

（式（１）中、Ｒ^１は水素原子又はアルキル基であり、Ｒ^２は置換基を有してもよい芳香族基であり、Ｒ^３は置換基を有してもよいアルキレン基であり、Ｒ^４は、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホナト基、又は有機基であり、ｎは０〜３の整数である。Ｒ^３はＲ^２と結合して環状構造を形成してもよい。） The imidazole compound represented by the formula (1a) may be a compound represented by the following formula (1).

(In Formula (1), R ¹ is a hydrogen atom or an alkyl group, R ² is an aromatic group that may have a substituent, and R ³ is an alkylene group that may have a substituent. , R ⁴ is a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonate group, a phosphino group, a phosphinyl group, a phosphonate group, or an organic group, and n is 0 to 0 (It is an integer of ^3. R ³ may combine with R ² to form a cyclic structure.)

In formula (1), R ¹ is a hydrogen atom or an alkyl group. When R ¹ is an alkyl group, the alkyl group may be a linear alkyl group or a branched alkyl group. Although the carbon atom number of the said alkyl group is not specifically limited, 1-20 are preferable, 1-10 are preferable and 1-5 are more preferable.

Specific examples of the alkyl group suitable as R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, Isopentyl group, tert-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethyl-n-hexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group Group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, and n-icosyl group.

In Formula (1), R ² is an aromatic group that may have a substituent. The aromatic group that may have a substituent may be an aromatic hydrocarbon group that may have a substituent, or an aromatic heterocyclic group that may have a substituent.

  The type of the aromatic hydrocarbon group is not particularly limited as long as the object of the present invention is not impaired. The aromatic hydrocarbon group may be a monocyclic aromatic group, may be formed by condensation of two or more aromatic hydrocarbon groups, and two or more aromatic hydrocarbon groups may be a single bond. May be formed by bonding. As the aromatic hydrocarbon group, a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a phenanthrenyl group are preferable.

  The kind of the aromatic heterocyclic group is not particularly limited as long as the object of the present invention is not impaired. The aromatic heterocyclic group may be a monocyclic group or a polycyclic group. As the aromatic heterocyclic group, a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, an isoxazolyl group, an isothiazolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzoimidazolyl group are preferable.

  Examples of the substituent that the phenyl group, polycyclic aromatic hydrocarbon group, or aromatic heterocyclic group may have include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, and a nitroso group. , Sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group, ammonio group, and organic group. When a phenyl group, a polycyclic aromatic hydrocarbon group, or an aromatic heterocyclic group has a plurality of substituents, the plurality of substituents may be the same or different.

  When the substituent that the aromatic group has is an organic group, examples of the organic group include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group. This organic group may contain a bond or substituent other than a hydrocarbon group such as a hetero atom in the organic group. The organic group may be linear, branched or cyclic. This organic group is usually monovalent, but can be a divalent or higher organic group when a cyclic structure is formed.

  When the aromatic group has a substituent on the adjacent carbon atom, the two substituents bonded on the adjacent carbon atom may combine to form a cyclic structure. Examples of the cyclic structure include an aliphatic hydrocarbon ring and an aliphatic ring containing a hetero atom.

When the substituent that the aromatic group has is an organic group, the bond contained in the organic group is not particularly limited as long as the effect of the present invention is not impaired, and the organic group includes an oxygen atom, a nitrogen atom, a silicon atom, and the like. A bond containing a hetero atom may be included. Specific examples of the bond containing a hetero atom include an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, and an amino bond (—NR ^A —: R ^A represents a hydrogen atom or a monovalent organic group. shown) urethane bond, an imino bond ^{(-N = C (-R B)} -, - C (= NR B) -: R B represents a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, a sulfinyl Examples include a bond and an azo bond.

As the bond containing a hetero atom which the organic group may have, from the viewpoint of heat resistance of the imidazole compound represented by the formula (1a) or the formula (1), an ether bond, a thioether bond, a carbonyl bond, or a thiocarbonyl bond , Ester bond, amide bond, amino bond (—NR ^A —: ^RA represents a hydrogen atom or a monovalent organic group), urethane bond, imino bond (—N═C (—R ^B ) —, —C (= NR ^B) -: ^{R B} represents a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, a sulfinyl bond.

  When the organic group is a substituent other than a hydrocarbon group, the type of substituent other than the hydrocarbon group is not particularly limited as long as the object of the present invention is not impaired. Specific examples of substituents other than hydrocarbon groups include halogen atoms, hydroxyl groups, mercapto groups, sulfide groups, cyano groups, isocyano groups, cyanato groups, isocyanato groups, thiocyanato groups, isothiocyanato groups, silyl groups, silanol groups, alkoxy groups. , Alkoxycarbonyl group, amino group, monoalkylamino group, dialkylaluminum group, monoarylamino group, diarylamino group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxylate group, acyl group, acyloxy group, sulfino Group, sulfonate group, phosphino group, phosphinyl group, phosphonate group, alkyl ether group, alkenyl ether group, alkyl thioether group, alkenyl thioether group, aryl ether group, aryl thioether group and the like. The hydrogen atom contained in the substituent may be substituted with a hydrocarbon group. Further, the hydrocarbon group contained in the substituent may be linear, branched, or cyclic.

  Examples of the substituent that the phenyl group, the polycyclic aromatic hydrocarbon group, or the aromatic heterocyclic group has include an alkyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, and 1 to 12 carbon atoms. Are preferably an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, an arylamino group having 1 to 12 carbon atoms, and a halogen atom.

As R ² , the imidazole compound represented by the formula (1a) or the formula (1) can be synthesized inexpensively and easily, and the solubility of the imidazole compound in water or a water-soluble organic solvent is good. A phenyl group, a furyl group, and a thienyl group, which may have a hydrogen atom, are preferable.

In formula (1), R ³ is an alkylene group which may have a substituent. The substituent which the alkylene group may have is not particularly limited as long as the object of the present invention is not impaired. Specific examples of the substituent that the alkylene group may have include a hydroxyl group, an alkoxy group, an amino group, a cyano group, and a halogen atom. The alkylene group may be a linear alkylene group or a branched alkylene group, and a linear alkylene group is preferred. Although the carbon atom number of an alkylene group is not specifically limited, 1-20 are preferable, 1-10 are preferable and 1-5 are more preferable. The number of carbon atoms of the alkylene group does not include the carbon atom of the substituent that is bonded to the alkylene group.

  The alkoxy group as a substituent bonded to the alkylene group may be a linear alkoxy group or a branched alkoxy group. Although the carbon atom number of the alkoxy group as a substituent is not specifically limited, 1-10 are preferable, 1-6 are more preferable, and 1-3 are especially preferable.

  The amino group as a substituent bonded to the alkylene group may be a monoalkylamino group or a dialkylamino group. The alkyl group contained in the monoalkylamino group or dialkylamino group may be a linear alkyl group or a branched alkyl group. The number of carbon atoms of the alkyl group contained in the monoalkylamino group or dialkylamino group is not particularly limited, but is preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 3.

Specific examples of the alkylene group suitable as R ³ include methylene group, ethane-1,2-diyl group, n-propane-1,3-diyl group, n-propane-2,2-diyl group, and n-butane. -1,4-diyl group, n-pentane-1,5-diyl group, n-hexane-1,6-diyl group, n-heptane-1,7-diyl group, n-octane-1,8-diyl Group, n-nonane-1,9-diyl group, n-decane-1,10-diyl group, n-undecane-1,11-diyl group, n-dodecane-1,12-diyl group, n-tridecane- 1,13-diyl group, n-tetradecane-1,14-diyl group, n-pentadecane-1,15-diyl group, n-hexadecane-1,16-diyl group, n-heptadecane-1,17-diyl group N-octadecane-1,18-diyl group, n -Nonadecane-1,19-diyl group and n-icosane-1,20-diyl group are mentioned.

R ⁴ is a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonate group, a phosphino group, a phosphinyl group, a phosphonate group, or an organic group, and n is 0 to 3 Is an integer. When n is an integer of 2 to 3, the plurality of R ⁴ may be the same or different.

When R ⁴ is an organic group, the organic group is the same as the organic group that the aromatic group may have as a substituent for R ² .

When R ⁴ is an organic group, the organic group is preferably an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. As the alkyl group, a linear or branched alkyl group having 1 to 8 carbon atoms is preferable, and a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are more preferable. As the aromatic hydrocarbon group, a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a phenanthrenyl group are preferable, a phenyl group and a naphthyl group are more preferable, and a phenyl group is particularly preferable. As the aromatic heterocyclic group, a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, an isoxazolyl group, an isothiazolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzoimidazolyl group are preferable. A furyl group and a thienyl group are more preferable.

When R ⁴ is an alkyl group, the bonding position of the alkyl group on the imidazole ring is preferably any of the 2-position, 4-position, and 5-position, and more preferably the 2-position. When R ⁴ is an aromatic hydrocarbon group or an aromatic heterocyclic group, the bonding position of these groups on imidazole is preferably the 2-position.

  Among the imidazole compounds represented by the above formula (1a), a compound represented by the following formula (1-1a) is preferable because it can be synthesized inexpensively and easily.

（式（１−１ａ）中、Ｒ、Ｒ^４及びｎは、式（１ａ）と同じであり、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９は、それぞれ独立に、水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基であり、但し、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９のうち少なくとも１つは水素原子以外の基である。Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９のうち少なくとも２つが結合して環状構造を形成してもよい。ＲはＲ^７と結合して環状構造を形成してもよい。）

(In the formula (1-1a), R, R ⁴ and n are the same as in the formula (1a), and R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, Halogen atom, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonato group, amino group, ammonio group, Or an organic group, provided that at least one of R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ is a group other than a hydrogen atom, R ⁵ , R ⁶ , R ⁷ , R ⁸ , and (At least two of R ⁹ may combine to form a cyclic structure. R may combine with R ⁷ to form a cyclic structure.)

R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ are the same as those in formula (1-1) described later. In formula (1-1a), R may be bonded to R ⁷ to form a cyclic structure. For example, when R is an alkyl group which may have a substituent, R is bonded to R ^7. Thus, a ring structure may be formed.

Among the imidazole compounds represented by the above formula (1) or formula (1-1a), the following formula (1-1) can be synthesized inexpensively and easily and has excellent solubility in water and organic solvents. A compound represented by formula (1-1) is preferred, and a compound in which R ³ is a methylene group is more preferred.

（式（１−１）中、Ｒ^１、Ｒ^３、Ｒ^４、及びｎは、式（１）と同様であり、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９は、それぞれ独立に、水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基であり、ただし、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９のうち少なくとも１つは水素原子以外の基である。Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、及びＲ^９のうち少なくとも２つが結合して環状構造を形成してもよい。Ｒ^３はＲ^７と結合して環状構造を形成してもよい。）

(In Formula (1-1), R ¹ , R ³ , R ⁴ , and n are the same as in Formula (1), and R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ are each independently selected. Hydrogen atom, halogen atom, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group A group, an ammonio group, or an organic group, provided that at least one of R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ is a group other than a hydrogen atom, R ⁵ , R ⁶ , R ^7. , R ⁸ and R ⁹ may combine to form a cyclic structure, and R ³ may combine with R ⁷ to form a cyclic structure.)

When R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ are organic groups, the organic group is the same as the organic group that R ² in Formula (1) has as a substituent. R ⁵ , R ⁶ , R ⁷ and R ⁸ are preferably a hydrogen atom from the viewpoint of solubility of the imidazole compound in a solvent.

Among them, at least one of R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ is preferably the following substituent, and R ⁹ is particularly preferably the following substituent. When R ⁹ is the following substituent, R ⁵ , R ⁶ , R ⁷ and R ⁸ are preferably hydrogen atoms.
-O-R ¹⁰
(R ¹⁰ is a hydrogen atom or an organic group.)

When R ¹⁰ is an organic group, the organic group is the same as the organic group that R ² in Formula (1) has as a substituent. R ¹⁰ is preferably an alkyl group, more preferably an alkyl group having 1 to 8 carbon atoms, particularly preferably an alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

（式（１−１−１）において、Ｒ^１、Ｒ^４、及びｎは、式（１）と同様であり、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４、及びＲ^１５は、それぞれ独立に、水素原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基であり、ただし、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４、及びＲ^１５のうち少なくとも１つは水素原子以外の基である。） Among the compounds represented by the formula (1-1), a compound represented by the following formula (1-1-1) is preferable.

(In Formula (1-1-1), R ¹ , R ⁴ and n are the same as in Formula (1), and R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are each independently , Hydrogen atom, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group, ammonio group Or an organic group, provided that at least one of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ is a group other than a hydrogen atom.)

Among the compounds represented by formula (1-1-1), at least one of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ is a group represented by the aforementioned —O—R ^10. It is preferable that R ¹⁵ is a group represented by —O—R ¹⁰ . When R ¹⁵ is a group represented by —O—R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are preferably hydrogen atoms.

The method for synthesizing the imidazole compound represented by the above formula (1a) is not particularly limited. For example, a halide represented by R ² CR (Hal) R (R ² and R are the same as those in formula (1a), Hal is a halogen atom), and a formula (II) described later. The imidazole compound represented by the above formula (1a) can be synthesized by reacting with an imidazole compound according to a conventional method to perform imidazolylation.

  The method for synthesizing the imidazole compound represented by the above formula (1) is not particularly limited. For example, the halogen-containing carboxylic acid derivative represented by the following formula (I) and the imidazole compound represented by the following formula (II) are reacted according to a conventional method to perform imidazolylation, whereby the above formula (1) The imidazole compound represented by can be synthesized.

（式（Ｉ）及び式（ＩＩ）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４及びｎは、式（１）と同様である。式（Ｉ）において、Ｈａｌはハロゲン原子である。）

(In formula (I) and formula (II), R ¹ , R ² , R ³ , R ⁴ and n are the same as in formula (1). In formula (I), Hal is a halogen atom.)

When the imidazole compound is a compound represented by the formula (1) and R ³ is a methylene group, that is, when the imidazole compound is a compound represented by the following formula (1-2), The imidazole compound can also be synthesized by the method using the Michael addition reaction described.

（式（１−２）中、Ｒ^１、Ｒ^２、Ｒ^４及びｎは、式（１）と同様である。）

(In formula (1-2), R ¹ , R ² , R ⁴ and n are the same as in formula (1).)

  Specifically, for example, the Michael addition reaction is caused by mixing a 3-substituted acrylic acid derivative represented by the following formula (III) and an imidazole compound represented by the above formula (II) in a solvent. The imidazole compound represented by the above formula (1-2) is obtained.

（式（ＩＩＩ）中、Ｒ^１、及びＲ^２は、式（１）と同様である。）

(In formula (III), R ¹ and R ² are the same as in formula (1).)

  Moreover, the imidazole compound represented by a following formula (1-3) is obtained by adding the 3-substituted acrylic acid derivative containing the imidazolyl group represented by the following formula (IV) in the solvent containing water. .

（式（ＩＶ）及び式（１−３）中、Ｒ^２、Ｒ^４及びｎは、式（１）と同様である。）

(In formula (IV) and formula (1-3), R ² , R ⁴ and n are the same as in formula (1).)

  In this case, by hydrolysis of the 3-substituted acrylic acid derivative represented by the above formula (IV), the imidazole compound represented by the above formula (II) and the 3-substituted acrylic acid represented by the following formula (V) And generate. A Michael addition reaction occurs between the 3-substituted acrylic acid represented by the following formula (V) and the imidazole compound represented by the above formula (II), and is represented by the above formula (1-3). An imidazole compound is formed.

（式（Ｖ）中、Ｒ^２は、式（１）と同様である。）

(In formula (V), R ² is the same as in formula (1).)

Preferable specific examples of the imidazole compound represented by the formula (1a) or the formula (1) include the following.

  The content of the imidazole compound represented by the formula (1a) is, for example, 0.1% by mass, preferably 0.3% by mass, more preferably 0.8% as a lower limit with respect to the mass of the lithography cleaning liquid of the present embodiment. The upper limit is, for example, 10% by mass, preferably 7% by mass, and more preferably 5% by mass. Within such a range, residues remaining after the etching treatment can be effectively removed while suppressing metal corrosion on the substrate surface.

[Water-soluble organic solvent]
The lithography cleaning liquid of this embodiment may further contain a water-soluble organic solvent. As the water-soluble organic solvent, a compound commonly used in the field can be used. A water-soluble organic solvent may be used independently and may be used in combination of 2 or more type.

  Examples of the water-soluble organic solvent include sulfoxides such as dimethyl sulfoxide; sulfones such as dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) sulfone, and tetramethylene sulfone; N, N-dimethylformamide, N-methylformamide Amides such as N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, N Lactams such as hydroxyethyl-2-pyrrolidone; lactones such as β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone; 1,3-dimethyl- 2-Imidazolidinone, 1,3-diechi Imidazolidinones such as 2-imidazolidinone and 1,3-diisopropyl-2-imidazolidinone; ethylene glycol, propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene Polyhydric alcohols such as glycol, glycerin and diethylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoallyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether , Propylene glycol monopropyl ether, propylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol , Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monobenzyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tripropylene glycol monobutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, Glycol ether solvents such as reethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether and diethylene glycol diethyl ether; glycol esters such as ethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate and diethylene glycol monoacetate Mention may be made of solvents.

  Among them, preferable water-soluble organic solvents are selected from dipropylene glycol monomethyl ether (DPM), propylene glycol (PG), 3-methoxy-3-methyl-1-butanol, dimethyl sulfoxide, propylene glycol monomethyl ether, propylene glycol It is at least one selected from the group consisting of monoethyl ether, propylene glycol monopropyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

  When the water-soluble organic solvent is contained, the content thereof is preferably 1 to 90% by mass, more preferably 10 to 85% by mass, and 30 to 80% by mass with respect to the total amount of the cleaning liquid for lithography. More preferably, it is still more preferably 40 to 75% by mass. By setting it as such content, it remains after an etching process, suppressing the corrosion of at least 1 sort (s) of metal selected from the group which consists of an easily corrosive metal, especially cobalt, copper, and these alloys. Residues can be effectively removed.

[Other ingredients]
Other components such as a surfactant may be added to the lithography cleaning liquid of the present embodiment as long as the effects of the present invention are not impaired. The surfactant is not particularly limited, and examples thereof include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

  Further, the cleaning liquid for lithography of the present embodiment does not need to contain another corrosion inhibitor (anticorrosive) as long as it contains the imidazole compound represented by the above general formula (1a). It may also contain a corrosion inhibitor. Such other corrosion inhibitors are not particularly limited, and examples thereof include benzotriazole, aminotetrazole, 5-amino-1-phenyltetrazole, 5-amino-1- (1-naphthyl) tetrazole, and 1-methyl-5- In addition to nitrogen-containing heterocyclic compounds such as aminotetrazole, 1,5-diaminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, pyrroline, secondary amine compounds, amino acid compounds, etc. .

<Washing method>
A cleaning method using the cleaning liquid of the present invention is also one aspect of the present invention.
The cleaning method of the present invention is a method for cleaning a substrate using the above-described lithography cleaning liquid. For example, the cleaning method of the present embodiment is performed in an etching mask layer forming process for forming an etching mask layer having a predetermined pattern on the surface of the substrate, and in a subsequent process of the etching process for etching the substrate exposed from the etching mask layer. In other words, this is a method of cleaning the etched substrate. The cleaning method of this embodiment is suitable when at least a part of the surface of the substrate is made of at least one metal selected from the group consisting of cobalt and copper and any of these alloys. At this time, at least part of the metal is exposed on the surface of the substrate and comes into contact with the cleaning liquid for lithography, but corrosion of the metal is satisfactorily suppressed. Therefore, by using the above-described lithography cleaning liquid, it is possible to effectively remove residues remaining after the etching process while suppressing metal corrosion.

[Examples 1 and 2]
As an imidazole compound, compound 1 having the following structure was synthesized by the method shown below. And the material shown in Table 1 was mixed in the quantity shown in Table 1, and the washing | cleaning liquid for lithography was prepared. In the table, TMAH represents tetramethylammonium hydroxide, DPM represents dipropylene glycol monomethyl ether, and PG represents propylene glycol.

(Synthesis example)
Compound 1 was synthesized by the following method.
First, 30 g of cinnamic acid derivative having the structure of the following formula was dissolved in 200 g of methanol, and then 7 g of potassium hydroxide was added to the methanol. The methanol solution was then stirred at 40 ° C. Methanol was distilled off and the residue was suspended in 200 g of water. To the obtained suspension, 200 g of tetrahydrofuran was mixed and stirred, and the aqueous phase was separated. Under ice cooling, 4 g of hydrochloric acid was added and stirred, and then 100 g of ethyl acetate was mixed and stirred. After allowing the mixture to stand, the oil phase was collected. The target product was crystallized from the oil phase, and the precipitate was collected to obtain an imidazole compound (compound 1) having the above structure.

The measurement result of ¹ H-NMR of the imidazole compound (compound 1) having the above structure is as follows.
¹ H-NMR (DMSO): 11.724 (s, 1H), 7.838 (s, 1H), 7.340 (d, 2H, J = 4.3 Hz), 7.321 (d, 1H, J = 7.2 Hz), 6.893 (d, 2H, J = 4.3 Hz), 6.876 (d, 1H, J = 6.1 Hz), 5.695 (dd, 1H, J = 4.3 J, 3.2J), 3.720 (s, 3H), 3.250 (m, 2H)

[Comparative Example 1]
Instead of Compound 1, imidazole having the following structure was prepared as Comparative Compound 1. Then, the materials shown in Table 1 were mixed in the amounts shown in Table 1 to prepare a comparative lithography cleaning solution.

[Comparative Examples 2 and 3]
Without adding a corrosion inhibitor (imidazole compound, comparative compound 1), the materials shown in Table 1 were mixed in the amounts shown in Table 1 to prepare a cleaning liquid for lithography.

[Evaluation of etching rate]
Copper or cobalt was deposited on a silicon substrate to obtain a silicon substrate having a 100 nm copper layer or cobalt layer. The silicon substrate was immersed in the lithography cleaning liquid heated to 50 ° C. for 60 minutes. After the immersion, the silicon substrate was rinsed with pure water, the film thickness of the copper layer or cobalt layer was measured, and the etching rate of the copper layer or cobalt layer was determined from the difference in film thickness before and after immersion. The results are shown in Table 1.

  From Table 1, it was confirmed that the cleaning liquids for lithography of Examples 1 and 2 containing Compound 1 were excellent in the corrosion inhibiting function for copper and cobalt compared to Comparative Examples 2 and 3 not containing a corrosion inhibitor. In Comparative Example 1 containing imidazole (Comparative Compound 1) not included in the formula (1a), the etching rate for cobalt was lower than those in Comparative Examples 2 and 3, but the etching rate for copper was significantly higher, and corrosion for copper was accelerated. It has been confirmed. It was confirmed that the cleaning liquid for lithography of Example 1 containing Compound 1 was superior in corrosion inhibiting function against copper and cobalt compared to Comparative Example 1 containing imidazole (Comparative Compound 1) at the same content as Compound 1. It was. Moreover, since the cleaning liquid for lithography of Example 1 was superior to the corrosion inhibiting function against cobalt confirmed in Comparative Example 1, it was confirmed that the lithography cleaning liquid was particularly excellent in corrosion inhibiting function against cobalt.

Claims (6)

A lithography cleaning liquid containing a basic compound, water, and an imidazole compound represented by the following formula (1a).

(In the formula, R each independently represents a hydrogen atom or a monovalent organic group, R ² represents an aromatic group which may have a substituent, and R ⁴ each independently represents a halogen atom, a hydroxyl group, A mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonate group, a phosphino group, a phosphinyl group, a phosphonate group, or an organic group, and n represents an integer of 0 to 3. The above R represents the other. And may be bonded to R or R ² to form a cyclic structure.) The lithography liquid for lithography according to claim 1, wherein the imidazole compound is a compound represented by the following general formula (1).

(Wherein R ² , R ⁴ and n are the same as those in formula (1a), R ¹ represents a hydrogen atom or an alkyl group, and R ³ represents an alkylene group which may have a substituent. ³ may combine with R ² to form a cyclic structure.)   The lithography cleaning liquid according to claim 1, further comprising a water-soluble organic solvent.   The lithography cleaning liquid according to any one of claims 1 to 3, which is used for cleaning a substrate having on its surface at least one metal selected from the group consisting of cobalt and copper and any of these alloys.   A method for cleaning a substrate using the lithography cleaning liquid according to claim 1.   The method according to claim 5, wherein at least a part of the surface of the substrate is made of at least one metal selected from the group consisting of cobalt and copper and any alloy thereof.