JP6630183B2 - Cleaning solution for lithography and cleaning method - Google Patents

Description

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

  A semiconductor device is formed by stacking a metal wiring layer, a low dielectric layer, an insulating layer, and the like on a substrate such as a silicon wafer, and such a semiconductor device is subjected to an etching process using a resist pattern as a mask. It is manufactured by processing each of the above layers by a lithography method.

  The resist film used in the above lithography method, a temporary laminated film (also referred to as a sacrificial film), and a residue derived from a metal wiring layer or a low dielectric layer generated in the etching step do not hinder the next step. The semiconductor device 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 containing a quaternary ammonium hydroxide as a main component has been proposed (for example, see Patent Document 1). The cleaning liquid for lithography containing such a quaternary ammonium compound as a main component has a greatly improved removal performance for various types of residues as compared with the previous cleaning liquid, and has an excellent corrosion inhibiting function for aluminum wiring. there were.

JP-A-2002-357908

  In recent years, a wiring forming method using a damascene method has been adopted with the increase in density and integration of semiconductor devices. In such a wiring forming method, copper, a copper alloy, or the like is employed as a metal wiring material constituting a metal wiring layer of a semiconductor device. Cobalt has also been adopted as a metal wiring material in a semiconductor device 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 lithography cleaning solution. Therefore, there is a need for a lithography cleaning solution that does not easily cause corrosion of copper, cobalt, and their alloys during substrate cleaning.

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

  The present inventors have intensively studied to solve the above problems. As a result, they have found that the above-mentioned problems can be solved by adding a specific imidazole compound to a cleaning liquid for lithography, and have completed the present invention. 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。） A 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).

(Wherein, R independently represents a hydrogen atom or a monovalent organic group, R ² represents an aromatic group which may have a substituent, R ⁴ each independently represents a halogen atom, a hydroxyl group, Represents a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonate group, or an organic group, and n represents an integer of 0 to 3. R or R ² and ring structure by bonding with may be formed.)

  A second aspect of the present invention is a method for cleaning a substrate using the cleaning liquid for lithography of 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 easily corrosive metal, and the method of wash | cleaning a board | substrate using this cleaning liquid for lithography can be provided.

<Lithography cleaning liquid>
The cleaning solution 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 “lithography cleaning liquid” in this specification. Further, such a cleaning liquid may contain a water-soluble organic solvent from the viewpoint of ensuring the cleaning function.

  The cleaning liquid for lithography of the present embodiment is suitably used for cleaning a substrate having a metal on its surface. The substrate having a metal on its 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 another metal structure on a substrate on which a 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, and the like 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 cleaning liquid for lithography of the present embodiment is suitably used for cleaning a substrate having on its surface at least one metal selected from the group consisting of cobalt, copper, and any alloy thereof. As an alloy of any of cobalt and copper, 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, and the like) is given, Specifically, a phosphorus- and / or boron-containing alloy such as CoWPB and a silicide such as CoSi are exemplified.

  The cleaning liquid for lithography 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 a corrosion inhibitor, particularly a corrosion inhibitor suitable for easily corrosive metals. Therefore, even when the cleaning liquid for lithography of the present embodiment comes into contact with the metal on the substrate surface during cleaning of the substrate, corrosion of the metal is favorably suppressed. Although the mechanism of action is not clear, it is considered that the imidazole compound reacts with the metal ion to form a chemical conversion coating on the surface of the metal, and that the chemical conversion coating suppresses metal corrosion. Can be

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

[Basic compound]
The basic compound is not particularly limited as long as it has a washing function. The basic compounds may be used alone or in combination of two or more.

  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 each independently represent 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 a carbon atom. It represents a hydroxyalkyl group having 1 to 16 atoms.

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

  Alkanolamine can be used as the 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.

  As the basic compound, for example, an inorganic base may be used in combination with a quaternary ammonium hydroxide. As the inorganic base, hydroxides of alkali metals 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 from 0.05 to 10% by mass, more preferably from 0.1 to 5% by mass, for the quaternary ammonium hydroxide, based on the total amount of the cleaning liquid for lithography. Preferably, the content of alkanolamine is 0.05 to 20% by mass, more preferably 0.1 to 10% by mass. With such a content, the corrosion-resistant metal, in particular, cobalt, copper, and at least one metal selected from the group consisting of alloys thereof are suppressed from corroding, so that the metal remains after the etching treatment. Residue can be effectively removed. When the inorganic base is used in combination with a quaternary ammonium hydroxide, the content of the inorganic base is preferably from 0.1% by mass to 1% by mass, and more preferably from 1% by mass to More preferably, it is 1000 mass ppm. With such a content, the corrosion-resistant metal, in particular, cobalt, copper, and at least one metal selected from the group consisting of alloys thereof are suppressed from corroding, and remain after the etching treatment. Residues can be effectively removed.

[water]
As the water, it is preferable to use pure water, deionized water, ion-exchanged water and the like.
The content of water is preferably from 10 to 80% by mass, more preferably from 15 to 70% by mass, still more preferably from 20 to 50% by mass, based on the total amount of the cleaning liquid for lithography. Even more preferably, it is 40% by mass. With such a content, the corrosion-resistant metal, in particular, cobalt, copper, and at least one metal selected from the group consisting of alloys thereof are suppressed from corroding, and remain after the etching treatment. Residues can be effectively removed.

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

In the 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 which may have a substituent, an aromatic group which may have a substituent, and the like. May have an ester bond or the like. The alkyl group may be the same as, for example, R ¹ or the like in the formula (1) described below, and 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. The substituent which the alkyl group may have may be, for example, the same as the substituent which the alkylene group represented by R ³ in formula (1) described below may have. The aromatic group which may have a substituent group, is the same as R ² in Formula (1) below, the aryl group is preferably a phenyl group is more preferable. 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, and one R is a hydrogen atom and the other R is an alkyl group which may have a substituent or an aromatic which may have a substituent. More preferably, it is a group. In the formula (1a), R may combine with 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 is to form a cyclic structure in combination with the other R or R ^2.

（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 the formula (1), R ¹ is a hydrogen atom or an alkyl group, R ² is an aromatic group which may have a substituent, and R ³ is an alkylene group which 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 sulfonato group, a phosphino group, a phosphinyl group, a phosphonat group, or an organic group; It is an integer of ^3. R ³ may combine with R ² to form a cyclic structure.)

In the 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 straight-chain alkyl group or a branched-chain alkyl group. Although the number of carbon atoms of the alkyl group is not particularly limited, it is preferably 1 to 20, preferably 1 to 10, and more preferably 1 to 5.

Specific examples of the alkyl group suitable as R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an 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, 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 the formula (1), R ² is an aromatic group which may have a substituent. The aromatic group which may have a substituent may be an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which 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 hindered. The aromatic hydrocarbon group may be a monocyclic aromatic group, or may be formed by condensing two or more aromatic hydrocarbon groups, or a single bond of two or more aromatic hydrocarbon groups. And 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 hindered. 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 benzimidazolyl group are preferable.

  Examples of the substituent which 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. , A sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonate group, an amino group, an ammonium group, and an organic group. When the phenyl group, polycyclic aromatic hydrocarbon group, or aromatic heterocyclic group has a plurality of substituents, the plurality of substituents may be the same or different.

  When the substituent of the aromatic group 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 a 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 may be a divalent or higher organic group when a cyclic structure is formed.

  When an aromatic group has a substituent on an adjacent carbon atom, the two substituents attached 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 of the aromatic group is an organic group, the bond contained in the organic group is not particularly limited as long as the effects of the present invention are not impaired, and the organic group may be an oxygen atom, a nitrogen atom, a silicon atom, or the like. 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- : ^RA 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 And an azo bond.

The bond containing a hetero atom that the organic group may have is an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond from the viewpoint of the heat resistance of the imidazole compound represented by the formula (1a) or (1). , an ester bond, an amide bond, amino bond ^{(-NR a} -: ^R a represents a hydrogen atom or a monovalent organic group) 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, and a sulfinyl bond.

  When the organic group is a substituent other than a hydrocarbon group, the type of the substituent other than the hydrocarbon group is not particularly limited as long as the object of the present invention is not hindered. Specific examples of the substituent other than the hydrocarbon group include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, an isothiocyanato group, a silyl group, a silanol group, and an alkoxy group. , 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, sulfonato group, phosphino group, phosphinyl group, phosphonate group, alkyl ether group, alkenyl ether group, alkylthio ether group, alkenyl thioether group, aryl ether group, aryl thioether group and the like. The hydrogen atom contained in the above substituent may be substituted by a hydrocarbon group. Further, the hydrocarbon group contained in the substituent may be any of linear, branched and cyclic.

  Examples of the substituent of the phenyl group, the polycyclic aromatic hydrocarbon group, or the aromatic heterocyclic group 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 preferred, an alkoxy 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 (1) can be synthesized at low cost and easily, and the imidazole compound has good solubility in water and a water-soluble organic solvent. And a phenyl group, a furyl group, and a thienyl group which may have

In the 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 which 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 is preferably a linear alkylene group. The number of carbon atoms in the alkylene group is not particularly limited, but is preferably 1 to 20, preferably 1 to 10, and more preferably 1 to 5. Note that the number of carbon atoms of the alkylene group does not include the carbon atoms of the substituents bonded to the alkylene group.

  The alkoxy group as a substituent bonded to the alkylene group may be a straight-chain alkoxy group or a branched-chain alkoxy group. The number of carbon atoms of the alkoxy group as a substituent is not particularly limited, but is preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 3.

  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 the 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 the 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 a methylene group, an ethane-1,2-diyl group, an n-propane-1,3-diyl group, an n-propane-2,2-diyl group, an 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.

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 sulfonato group, a phosphino group, a phosphinyl group, a phosphonat group, or an organic group; Is an integer. When n is an integer of 2 to 3, a plurality of R ⁴ may be the same or different.

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

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 benzimidazolyl group are preferable. A furyl group and a thienyl group are more preferred.

When R ⁴ is an alkyl group, the bonding position of the alkyl group on the imidazole ring is preferably any of 2-position, 4-position, and 5-position, and more preferably 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), compounds represented by the following formula (1-1a) are preferable because they can be easily synthesized at low cost.

（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, sulfonato group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group, ammonium 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, and 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 in the formula (1-1) described later. In the 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 To form a ring structure.

Among the imidazole compounds represented by the above formula (1) or formula (1-1a), the following formula (1-1) can be easily synthesized at low cost and has excellent solubility in water and organic solvents. Is preferable, and a compound represented by the formula (1-1), wherein R ³ is a methylene group, is more preferable.

（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 A hydrogen atom, 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 sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonate group, and an amino group. group, an ammonio group, or an organic group, provided ^{that, R 5, R 6, R} 7, at least one of ^{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. 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 groups are the same as the organic groups that R ² in Formula (1) has as a substituent. R ⁵ , R ⁶ , R ⁷ , and R ⁸ are preferably hydrogen atoms from the viewpoint of solubility of the imidazole compound in the solvent.

Among them, at least one of R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ is preferably the following substituent, and it is particularly preferable that R ⁹ is the following substituent. When R ⁹ is the following substituent, R ⁵ , R ⁶ , R ⁷ , and R ⁸ are preferably a hydrogen atom.
-OR 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 the formula (1-1-1), R ¹ , R ⁴ , and n are the same as in the 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, sulfonato group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group, ammonium 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 the formula (1-1-1), at least one of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ is a group represented by -OR ¹⁰ described above. 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 a hydrogen atom.

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 in the formula (1a), and Hal is a halogen atom), and a halide represented by the following formula (II) The imidazole compound represented by the formula (1a) can be synthesized by reacting the imidazole compound 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, by reacting a halogen-containing carboxylic acid derivative represented by the following formula (I) with an imidazole compound represented by the following formula (II) according to a conventional method to perform imidazolylation, the above-mentioned formula (1) 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 the formulas (I) and (II), R ¹ , R ² , R ³ , R ⁴ and n are the same as those in the formula (1). In the formula (I), Hal is a halogen atom.)

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

  Specifically, for example, 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 to cause a Michael addition reaction. As a result, an 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 the formula (III), R ¹ and R ² are the same as in the formula (1).)

  In addition, an imidazole compound represented by the following formula (1-3) is obtained by adding a 3-substituted acrylic acid derivative containing an imidazolyl group represented by the following formula (IV) to a 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 the formula (IV) and the formula (1-3), R ² , R ⁴ and n are the same as in the formula (1).)

  In this case, the imidazole compound represented by the formula (II) and the 3-substituted acrylic acid represented by the following formula (V) are obtained by hydrolysis of the 3-substituted acrylic acid derivative represented by the formula (IV). And generate. Then, 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 the formula (V), R ² is the same as in the formula (1).)

Preferred 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 0.1% by mass, as the lower limit value, based on the mass of the lithography cleaning solution 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 corrosion of the metal on the substrate surface.

[Water-soluble organic solvent]
The cleaning liquid for lithography of the present embodiment may further contain a water-soluble organic solvent. As the water-soluble organic solvent, compounds commonly used in the art can be used. The water-soluble organic solvents may be used alone or in combination of two or more.

  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, and 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 ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether and diethylene glycol diethyl ether; glycol ester solvents such as ethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate and diethylene glycol monoacetate Solvents can be mentioned.

  Among them, preferred 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, and 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 a water-soluble organic solvent is contained, its content is preferably from 1 to 90% by mass, more preferably from 10 to 85% by mass, and more preferably from 30 to 80% by mass, based on the total amount of the cleaning liquid for lithography. More preferably, it is even more preferably 40 to 75% by mass. With such a content, the corrosion-resistant metal, in particular, cobalt, copper, and at least one metal selected from the group consisting of alloys thereof are suppressed from corroding, and remain after the etching treatment. Residues can be effectively removed.

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

  The cleaning liquid for lithography of the present embodiment does not need to contain any other corrosion inhibitor (corrosion inhibitor) as long as it contains the imidazole compound represented by the general formula (1a). May also be included. Such other corrosion inhibitors are not particularly restricted but include, for example, benzotriazole, aminotetrazole, 5-amino-1-phenyltetrazole, 5-amino-1- (1-naphthyl) tetrazole, 1-methyl-5- Nitrogen-containing heterocyclic compounds such as aminotetrazole, 1,5-diaminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, and pyrroline, as well as secondary amine compounds and amino acid compounds. .

<Washing method>
The cleaning method using the cleaning liquid of the present invention is also one of the present invention.
The cleaning method of the present invention is a method of cleaning a substrate using the above-described cleaning liquid for lithography. For example, the cleaning method of the present embodiment is performed in a post-process of an etching mask layer forming step of forming an etching mask layer having a predetermined pattern on the surface of the substrate and an etching step of etching the substrate exposed from the etching mask layer. This is a method of cleaning the etched substrate. The cleaning method of the present 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, copper, and any alloy thereof. At this time, at least a part of the metal is exposed on the surface of the substrate and comes into contact with the cleaning liquid for lithography, but the corrosion of the metal is favorably suppressed. Therefore, by cleaning using the above-described cleaning liquid for lithography, residues remaining after the etching treatment can be effectively removed while suppressing corrosion of metal.

[Examples 1 and 2]
Compound 1 having the following structure was synthesized as an imidazole compound by the method shown below. Then, the materials shown in Table 1 were mixed in the amounts shown in Table 1 to prepare a cleaning liquid for lithography. 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 a cinnamic acid derivative having the following structure was dissolved in 200 g of methanol, and 7 g of potassium hydroxide was added to methanol. Then the methanol solution was stirred at 40 ° C. The methanol was distilled off, and the residue was suspended in 200 g of water. 200 g of tetrahydrofuran was mixed and stirred with the obtained suspension, 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 separated. The target substance was crystallized from the oil phase, and the precipitate was collected to obtain an imidazole compound (Compound 1) having the above structure.

¹ H-NMR measurement results of the imidazole compound (Compound 1) having the above structure are as follows.
^{1 H-NMR (DMSO):} 11.724 (s, 1H), 7.838 (s, 1H), 7.340 (d, 2H, J = 4.3Hz), 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 the 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 formed on a silicon substrate to obtain a silicon substrate provided with a 100-nm copper layer or a cobalt layer. The silicon substrate was immersed in the cleaning liquid for lithography heated to 50 ° C. for 60 minutes. After the immersion, the silicon substrate was rinsed with pure water, the thickness of the copper layer or the cobalt layer was measured, and the etching rate of the copper layer or the cobalt layer was determined from the difference in the thickness before and after the immersion. Table 1 shows the results.

  From Table 1, it was confirmed that the cleaning liquids for lithography of Examples 1 and 2 containing Compound 1 were superior in the function of inhibiting corrosion of copper and cobalt as compared with Comparative Examples 2 and 3 containing no 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 that of Comparative Examples 2 and 3, but the etching rate for copper was significantly higher, and corrosion to copper was accelerated. It was confirmed that it was. The cleaning liquid for lithography of Example 1 containing Compound 1 was confirmed to be superior in the function of inhibiting corrosion of copper and cobalt as compared with Comparative Example 1 containing imidazole (Comparative Compound 1) at the same content as Compound 1. Was. Further, the cleaning liquid for lithography of Example 1 was superior to the corrosion inhibiting function for cobalt confirmed in Comparative Example 1, and thus was confirmed to be particularly excellent in the corrosion inhibiting function for cobalt.

Claims (4)

A cleaning solution for lithography used for cleaning a substrate having on its surface at least one metal selected from the group consisting of cobalt and an alloy of cobalt,
A cleaning liquid for lithography containing a basic compound, water, and an imidazole compound represented by the following formula (1) .

( Wherein , R ¹ represents a hydrogen atom or an alkyl group, R ² represents an aromatic group which may have a substituent , R ³ represents an alkylene group which may have a substituent, R ⁴ Are each independently 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 sulfonato group, a phosphino group, a phosphinyl group, a phosphonate group, or an alkyl group or alkenyl group which may contain a hetero atom. Represents a group, a cycloalkyl group, a cycloalkenyl group, an aryl group, or an aralkyl group , and n represents an integer of 0 to ^3. R ³ may combine with R ² to form a cyclic structure.) Furthermore, a water-soluble organic solvent, cleaning solution for lithography of the mounting serial to claim 1. The cleaning solution for lithography according to claim 1 or 2, wherein the basic compound is a quaternary ammonium hydroxide. A method for cleaning a substrate, wherein at least a part of the surface is made of at least one metal selected from the group consisting of cobalt and an alloy of cobalt, using the cleaning liquid for lithography according to any one of claims 1 to 3 .