TWI675125B - Etching liquid, replenishing liquid, and method of forming copper wiring - Google Patents

Abstract

The etchant of the present invention is an etchant of copper; and the aforementioned etchant is an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a five-membered ring, and a member selected from the group consisting of a heterocyclic compound having a five- to six-membered ring. An aqueous solution of one or more compounds in the group consisting of an aromatic compound (B1) and an alkanolamine (B2); the aforementioned (A) is a heterocyclic ring having no hydroxyalkyl group and having one or more nitrogen atoms as a ring; Atom heteroaromatic compound; the aforementioned (B1) is a heteroaromatic compound having one or more nitrogen atoms as a heteroatom constituting a ring and substituted with a substituent containing a hydroxyalkyl group having 1 to 5 carbon atoms; (B2) is a compound having the general formula (1): R ¹ -N (R ² ) -R ³ (In the general formula (1), R ¹ and R ² independently represent an alkyl group or a carbon number of 1 to 8 A hydroxyalkyl group, R ³ represents a hydrogen atom, an alkyl group, or a hydroxyalkyl group having ¹ to 8 carbon atoms, and at least one of R ¹ to R ³ is the aforementioned hydroxyalkyl group).

Description

   Etching liquid, replenishing liquid, and method for forming copper wiring   

The present invention relates to a copper etching solution, a replenishing solution thereof, and a method for forming a copper wiring.

In the production of printed wiring boards, when a copper wiring pattern is formed by a photo ecthing method, iron chloride-based etching solutions, copper chloride-based etching solutions, and alkaline etching solutions have been used as etching solutions. . When these etching solutions are used, copper under a resist called side etching may be dissolved from the side of the wiring pattern. That is, it is expected that a portion covered with a resist and not removed by etching (that is, a copper wiring portion) is removed by an etchant, and a phenomenon that the width gradually decreases from the bottom to the top of the copper wiring is generated. Especially when the copper wiring pattern is fine, it is necessary to reduce such lateral etching as much as possible. In order to suppress this lateral etching, an etching solution prepared with an azole compound as a heteroaromatic five-membered ring compound has been proposed.

    [Prior technical literature]         [Patent Literature]    

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-332430.

Patent Document 2: Japanese Patent Application Laid-Open No. 2005-330572.

Patent Document 3: Japanese Patent Application Laid-Open No. 2009-79284.

Patent Document 4: Japanese Patent Application Laid-Open No. 2009-221596.

Regarding the etchant disclosed in the above-mentioned patent document, a certain lateral etching suppression effect can be expected. However, with the increase in the demand for refinement on the market, there is a need for an etchant that has the effect of suppressing lateral etching and that forms fine patterns of copper wiring.

The present invention has been made in view of the above-mentioned circumstances, and provides an etching solution with high suppression effect of lateral etching, excellent fine pattern formation of copper wiring, a replenishing solution thereof, and a method for forming a copper wiring.

The invention relates to an etching solution, which is an etching solution for copper. The etching solution contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a five-membered ring, and a compound selected from a heteroaromatic compound (B1) having a five- to six-membered ring and an alkanolamine ( B2) An aqueous solution of one or more compounds in the group. The above-mentioned five-membered heteroaromatic compound (A) is a heteroaromatic compound which does not have a hydroxyalkyl group and has one or more nitrogen atoms as heteroatoms constituting the ring. The above-mentioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring is a heteroatom having one or more nitrogen atoms and is substituted with a substituent containing a hydroxyalkyl group having 1 to 5 carbon atoms. Heteroaromatic compounds. The alkanolamine (B2) is a compound having the general formula: R ¹ -N (R ² ) -R ³ (in the general formula, R ¹ and R ² independently represent an alkyl group or a hydroxyalkane having 1 to 8 carbon atoms) R ³ represents a hydrogen atom, an alkyl group, or a hydroxyalkyl group having ¹ to 8 carbon atoms, and at least one of R ¹ to R ³ is the above-mentioned hydroxyalkyl group).

The present invention relates to a replenisher which is added to the etchant when the etchant is used continuously or repeatedly; and the replenisher is a heteroaromatic compound (A) containing the five-membered ring and the optional An aqueous solution of one or more compounds from the group consisting of a heteroaromatic compound (B1) having a five-membered ring to a six-membered ring and the alkanolamine (B2) is free.

The present invention relates to a method for forming a copper wiring. The method for forming a copper wiring etches a portion of a copper layer that is not covered by a resist; and the method for forming a copper wiring uses the above-mentioned etching solution to etch.

In addition, the "copper" in the said invention may consist only of copper, and may consist of a copper alloy. In addition, in this specification, "copper" means copper or a copper alloy.

The etching solution of the present invention contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a five-membered ring, and a member selected from a heteroaromatic compound (B1) having a five- to six-membered ring and an alkanolamine ( B2) one or more compounds in the group. It is considered that one or more compounds selected from the group consisting of a heteroaromatic compound (B1) having a five-membered ring to a six-membered ring and an alkanolamine (B2) can capture sub-atoms generated as the etching progresses. Copper ions are etched quickly in the vertical direction. Therefore, it is possible to provide an etching solution with high suppression effect of side etching, excellent pattern formation of copper wirings, a replenishing solution thereof, and a method for forming copper wirings.

1‧‧‧ substrate

2‧‧‧ Copper wiring

3‧‧‧Photoresist

T‧‧‧ the width of the bottom of the copper wiring

B‧‧‧ Width of the top of the copper wiring

FIG. 1 is a cross-sectional view showing an example of a copper wiring after being etched by the etching solution of the present invention.

    <Copper Etching Solution>    

The copper etching solution of the present invention contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a five-membered ring, and a heteroaromatic compound (B1) selected from a five-membered ring to a six-membered ring, and an alkane. An aqueous solution of one or more compounds in the group consisting of an alcohol amine (B2). The above-mentioned five-membered heteroaromatic compound (A) is a heteroaromatic compound which does not have a hydroxyalkyl group and has one or more nitrogen atoms as heteroatoms constituting the ring. The above-mentioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring is a heteroatom having one or more nitrogen atoms and is substituted with a substituent containing a hydroxyalkyl group having 1 to 5 carbon atoms. Heteroaromatic compounds. The alkanolamine (B2) is a compound having the general formula (1): R ¹ -N (R ² ) -R ³ (in the general formula (1), R ¹ and R ² independently represent an alkyl group or a carbon number 1 A hydroxyalkyl group of 8 or less, R ³ represents a hydrogen atom, an alkyl group, or a hydroxyalkyl group of ¹ to 8 carbons, and at least one of R ¹ to R ³ is the hydroxyalkyl group described above).

    <Acid>    

The acid of the present invention can be appropriately selected from inorganic acids and organic acids. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and hydrobromic acid. Examples of the organic acid include formic acid, acetic acid, oxalic acid, maleic acid, benzoic acid, and glycolic acid. Among the above acids, hydrochloric acid is preferred from the viewpoints of stability of the etching rate and stability of the dissolution of copper. As long as at least one kind of the acid is used, two or more kinds can be used in combination.

The concentration of the aforementioned acid is preferably 7 g / L to 180 g / L, and more preferably 18 g / L to 110 g / L. When the acid concentration is 7 g / L or more, the etching rate becomes faster, and thus copper can be quickly etched. In addition, when the acid concentration is 180 g / L or less, the dissolution stability of copper is maintained, and deterioration of the working environment can be suppressed.

    <Oxidizing metal ion>    

The oxidizing metal ion of the present invention may be a metal ion capable of oxidizing metallic copper, and may be, for example, copper ion, iron ion, or the like. From the viewpoint of suppressing lateral etching and the stability of the etching rate, it is preferable to use copper ions as the oxidizing metal ions. As long as at least one kind of the oxidizing metal ion is used, two or more kinds can be used in combination.

The oxidizing metal ion can be contained in an etching solution by blending an oxidizing metal ion source. For example, when a copper ion source is used as the oxidizing metal ion source, specific examples of the copper ion source include copper chloride, copper sulfate, copper bromide, copper salts of organic acids, and copper hydroxide. For example, when an iron ion source is used as the oxidizing metal ion source, specific examples of the iron ion source include iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, and iron salts of organic acids. Wait.

The concentration of the oxidizing metal ion is preferably 10 g / L to 300 g / L, more preferably 10 g / L to 250 g / L, still more preferably 15 g / L to 220 g / L, and even more preferably 30 g / L to 200 g. / L. When the concentration of the oxidizing metal ion is 10 g / L or more, since the etching rate is increased, copper can be etched quickly. In addition, when the concentration of the oxidizing metal ion is 300 g / L or less, the dissolution stability of copper is maintained.

    <Heteroaromatic compound (A) having a five-membered ring>    

The heteroaromatic compound (A) having a five-membered ring of the present invention is a heteroaromatic compound having no hydroxyalkyl group and having one or more nitrogen atoms as a heteroatom constituting the ring. As long as the heteroaromatic compound (A) having a five-membered ring described above is used at least one kind, two or more kinds can be used in combination.

From the viewpoints of structural stability and solubility in an acidic liquid, the above-mentioned heteroaromatic compound (A) having a five-membered ring is preferably a heteroatom having only nitrogen as a ring. Examples of such a five-membered heteroaromatic compound (A) include an imidazole compound having an imidazole skeleton, a pyrazole compound having a pyrazole skeleton, a triazole compound having a triazole skeleton, and a Tetrazole compounds such as azole compounds.

Examples of the imidazole compound include imidazoles such as imidazole, 2-methylimidazole, 2-undecyl-4-methylimidazole, and 2-phenylimidazole, and benzimidazole and 2-methylbenzimidazole. , Benzimidazoles such as 2-undecyl benzimidazole, 2-phenyl benzimidazole, 2-mercaptobenzimidazole, and the like. Among these compounds, benzimidazole is preferable.

Examples of the pyrazole compound include pyrazole, 3-methylpyrazole, 1-ethylpyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, and 3-amino-1-methyl Pyridazole, 4-chloropyrazole, 1,3,5-trimethylpyrazole and the like.

Examples of the triazole compound include 1,2,3-triazole, 1,2,4-triazole, 5-phenyl-1,2,4-triazole, and 5-amino-1,2, 4-triazole, benzotriazole, 1-methyl-benzotriazole, tolyltriazole and the like. Among these compounds, benzotriazole is preferable.

Examples of the tetrazole compound include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, and 5-mercapto-1H- Tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 1-cyclohexyl-5-mercapto-1H-tetrazole, 5,5'-bi-1H-tetrazole, and ammonium salts of these compounds or Metal salts such as sodium salt, zinc salt, calcium salt, potassium salt, etc.

Among the above-mentioned azole compounds, from the viewpoint of high undercut inhibitory effects, tetrazole compounds are preferred, and 1H-tetrazole, 5-phenyl-1H-tetrazole, and 5-amino- 1H-tetrazole, 5,5'-bi-1H-tetrazole, and ammonium salts or metal salts of these compounds, and more preferably 1H-tetrazole, 5-amino-1H-tetrazole, and ammonium salts of these compounds Or metal salt. It is estimated that these tetrazole compounds can form a protective film thinly and uniformly from the top to the side of the conductor pattern.

The concentration of the five-membered heteroaromatic compound (A) is preferably 0.1 g / L to 50 g / L, more preferably 0.1 g / L to 15 g / L, and still more preferably 0.2 g / L to 10 g / L. L. When the concentration of the five-membered heteroaromatic compound (A) is 0.1 g / L or more, undercuts can be reliably suppressed. On the other hand, when the concentration of the five-membered heteroaromatic compound (A) is 50 g / L or less, it is possible to prevent a decrease in the etching rate and reliably etch a portion to be etched, so it is possible to prevent A short circuit (poor insulation) occurs.

    <Heteroaromatic compound (B1) having a five-membered ring to a six-membered ring>    

The heteroaromatic compound (B1) having a five-membered ring to a six-membered ring of the present invention is a heteroatom having one or more nitrogen atoms as a ring, and is substituted by a substituent containing a hydroxyalkyl group having 1 to 5 carbon atoms. Substituted heteroaromatic compounds. The above-mentioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring can be used in combination of two or more kinds.

The above-mentioned hydroxyalkyl group-containing substituent (hereinafter also referred to as a hydroxyalkyl group-containing substituent) represents any one of a hydroxyalkyl group-containing substituent and a hydroxyalkyl-containing hydrocarbon derivative group having 1 to 10 carbon atoms. . The above-mentioned hydrocarbon derivative group having 1 to 10 carbons means a group in which a part of carbon or hydrogen in the hydrocarbon group may be substituted with other atoms (for example, sulfur atom, oxygen atom, fluorine atom, etc.) or a substituent. Examples of the hydrocarbon-derived group include alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, amino, aminoalkyl, ethenyl, and phenyl. The hydrocarbon derivative having 1 to 10 carbon atoms containing the hydroxyalkyl group may be, for example, a group in which one or two -H of amino groups represented by the following general formula (2) are substituted with a hydroxyalkyl group. , General formula (2): -XN (R ¹ ) -R ² (In the general formula (2), X represents an alkylene group having 1 to 10 carbon atoms, and R ¹ to R ² independently represent a hydrogen atom or carbon number 1 to 5 hydroxyalkyl group, R ¹ to R ² in at least one hydroxyalkyl group, the above-described alkylene group may have an ether bond, an ester bond, acyl amine bond, a urethane bond, etc.). The same applies to the following hydrocarbon-derived groups and hydroxyalkyl-containing substituents.

In addition, from the viewpoints of structural stability and solubility in an acidic liquid, the above-mentioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring preferably has only nitrogen as a heteroatom constituting the ring, or only A compound having nitrogen and sulfur as heteroatoms.

The above-mentioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring is preferably one or more selected from the group consisting of a compound having a hydroxyalkyl group-containing substituent and containing only a heterocyclic molecule in the molecule. Compound (b1-0) having an aromatic five-membered ring as a heterocyclic ring, compound (b1-1) containing only a heteroaromatic six-membered ring in the molecule, and a fused ring containing a heteroaromatic six-membered ring and a hetero five-membered ring in the molecule (b1-2), and a compound (b1-3) in which a heteroaromatic six-membered ring and a hetero five-membered ring are connected through a single bond or a divalent linking group.

The compound (b1-0) containing a heteroaromatic five-membered ring in the molecule is not particularly limited as long as it is a compound substituted with a substituent having a hydroxyalkyl group, and may be, for example, an imidazole compound having an imidazole skeleton and a pyridine An azole compound such as a pyrazole compound having an azole skeleton, a triazole compound having a triazole skeleton, or a tetrazole compound having a tetrazole skeleton. Specific examples include 2- (1-hydroxyethyl) benzimidazole, 4-hydroxymethyl-5-methylimidazole, 3,5-dimethyl-1-hydroxymethylpyrazole, and the like.

Examples of the compound (b1-1) containing a heteroaromatic six-membered ring in the molecule include, for example, a pyridine compound having a pyridine skeleton, a pyrimidine compound having a pyrimidine skeleton, a pyrazine compound having a pyrazine skeleton, and a pyridazine skeleton Pyridazine compounds and the like.

The pyridine compound is not particularly limited as long as it is a compound having a pyridine skeleton substituted with a hydroxyalkyl group-containing substituent, and examples thereof include a pyridine compound represented by the following general formula (3).

(In the general formula (3), R ¹ to R ⁵ independently represent a hydrogen atom, a hydroxyalkyl group-containing substituent, or a hydrocarbon derivative having 1 to 10 carbon atoms excluding a hydroxyalkyl group-containing substituent, and R ¹ To at least one of R ⁵ represents a hydroxyalkyl-containing substituent)

In addition, from the viewpoint of effectively suppressing the lateral etching, the hydrocarbon derivative having 1 to 10 carbons out of the hydrocarbon derivative having 1 to 10 carbons excluding the hydroxyalkyl-containing substituent is preferably derived from A hydrocarbon-derived group consisting of carbon and hydrogen. The same applies to the hydrocarbon derivative having 1 to 10 carbon atoms excluding the following hydroxyalkyl group-containing substituents.

Examples of the pyridine compound include 2-pyridinemethanol, 3-pyridinemethanol, 4-pyridinemethanol, 2-pyridineethanol, 3-pyridineethanol, 6-methyl-2-pyridinemethanol, and 6-methyl-3 -Pyridinemethanol, 2-amino-3-pyridinemethanol, pyridoxine hydrochloride and the like.

The pyrimidine compound is not particularly limited as long as it is a compound having a pyrimidine skeleton substituted with a hydroxyalkyl-containing substituent, and examples thereof include a pyridine compound represented by the following general formula (4).

(In the general formula (4), R ⁶ to R ⁹ independently represent a hydrogen atom, a hydroxyalkyl-containing substituent, or a hydrocarbon derivative having 1 to 10 carbon atoms excluding a hydroxyalkyl-containing substituent, and R ⁶ To at least one of R ⁹ represents a hydroxyalkyl-containing substituent)

Examples of the pyrimidine compound include 4-amino-2-methyl5-pyrimidinemethanol, 2-methyl-4-aminopyrimidine-5-methanol, 4-amino-2-methylthio-5-pyrimidinemethanol, 5-phenylpyrimidine-2-ethanol, 5- (4-methoxyphenyl) pyrimidine-2-ethanol, and the like.

The pyrazine compound is not particularly limited as long as it is a compound having a pyrazine skeleton substituted with a hydroxyalkyl group-containing substituent, and examples thereof include the pyrazine compound represented by the following general formula (5).

(In the general formula (5), R ¹⁰ to R ¹³ independently represent a hydrogen atom, a hydroxyalkyl-containing substituent, or a hydrocarbon derivative having 1 to 10 carbon atoms excluding a hydroxyalkyl-containing substituent, and R ¹⁰ To at least one of R ¹³ represents a hydroxyalkyl-containing substituent)

Examples of the pyrazine compound include 2-pyrazinemethanol, 5-methyl-2-pyrazinemethanol, 1- (3-fluoropyrazin-2-yl) ethanol, and α-phenyl-2-pyrazine Ethanol and so on.

The pyridazine compound is not particularly limited as long as it is a compound having a pyridazine skeleton substituted with a hydroxyalkyl group-containing substituent. For example, a pyridazine compound represented by the following general formula (6) can be exemplified.

(In the general formula (6), R ¹⁴ to R ¹⁷ independently represent a hydrogen atom, a hydroxyalkyl group-containing substituent, or a hydrocarbon derivative having 1 to 10 carbon atoms excluding a hydroxyalkyl group-containing substituent, and R ¹⁴ To at least one of R ¹⁷ represents a hydroxyalkyl-containing substituent)

Examples of the pyridazine compound include α-phenylpyridazine-3-methanol and α-phenylpyridazine-4-methanol.

Among the compounds (b1-1) containing only a heteroaromatic six-membered ring in the molecule, the above pyridine is preferred from the viewpoint of obtaining an etching solution having high side etching suppression effect and excellent fine pattern formation of copper wiring. The compound is more preferably 2-pyridinemethanol, 3-pyridinemethanol, 4-pyridinemethanol, 2-pyridineethanol, 3-pyridineethanol, pyridoxine hydrochloride.

The compound (b1-2) containing a fused ring having a heteroaromatic six-membered ring and a hetero five-membered ring in the molecule is not particularly limited as long as it is a compound containing the following fused ring in the molecule. The fused ring has a hydroxyalkyl group The heteroaromatic six-membered ring substituted by a substituent and / or the hetero five-membered ring substituted by a hydroxyalkyl-containing substituent, the compound (b1-2) may be, for example, 1- (hydroxymethyl) -1H -Benzotriazole, 1- (2-hydroxyethyl) -1H-benzotriazole, 2,2 '-(methyl-1H-benzotriazol-1-ylmethylimino) diethanol, 9- (2-hydroxyethyl) adenine and the like. Among these compounds, 1- (hydroxymethyl) -1H-benzotriazole is preferable.

    <Alkanolamine (B2)>    

The alkanolamine (B2) of the present invention is a compound having the general formula (1): R ¹ -N (R ² ) -R ³ (in the general formula (1), R ¹ and R ² independently represent an alkyl group or a carbon A hydroxyalkyl group having a number of 1 or more and 8 or less, R ³ represents a hydrogen atom, an alkyl group, or a hydroxyalkyl group having a carbon number of 1 or more and 8 or less, and at least one of R ¹ to R ³ is the above-mentioned hydroxyalkyl group). The said alkanolamine (B2) can use 2 or more types together.

Examples of the alkanolamine (B2) include dimethylaminoethanol, diethylaminoethanol, methylaminoethanol, ethylaminoethanol, dimethylaminopropanol, methylaminopropanol, and diethyl alcohol. Monohydric hydroxy alcohol compounds such as aminoaminopropanol and butylaminobutanol; dihydric hydroxy alcohol compounds such as diethanolamine, ethyldiethanolamine, and butyldiethanolamine; trihydric hydroxy alcohol compounds such as triethanolamine; and the like. Among these compounds, dimethylaminoethanol and diethylaminoethanol are preferred.

From the viewpoint of forming a fine pattern of copper wiring, one or more compounds selected from the group consisting of a heteroaromatic compound (B1) and an alkanolamine (B2) having a five-membered ring to a six-membered ring. The concentration is preferably 0.15 g / L or more, more preferably 0.2 g / L or more, still more preferably 0.3 g / L or more, and further preferably 30 g / L or less, more preferably 20 g / L or less, and further preferably It is 10 g / L or less.

In addition, from the viewpoint of forming a fine pattern of copper wiring, the above-mentioned heteroaromatic compound (A) having a five-membered ring and the above-mentioned heteroaromatic compound (B1) having a five- to six-membered ring and The weight ratio [(A) / ((B1) + (B2))] of one or more compounds in the group composed of alkanolamine (B2) is preferably 0.001 or more, more preferably 0.01 or more, and even more preferably It is 0.1 or more, more preferably 30 or less, more preferably 20 or less, and still more preferably 15 or less.

To the etchant of the present invention, in addition to the above-mentioned components, other components can be added to such an extent that the effects of the present invention are not impaired. As the other components, for example, an aliphatic acyclic compound such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine may be added; and pyrrole having a pyrrolidine skeleton Alkane compounds, pyridine compounds having a pyridine skeleton, pyrazine compounds having a pyrazine skeleton, homopyrazine compounds having a homopyrazine skeleton, hexahydro-1 having a hexahydro-1,3,5-triazine skeleton , 3,5-triazine compounds and other aliphatic heterocyclic compounds; dicyandiamine-diethylenetriamine polycondensate, dicyandiamine-formaldehyde polycondensate, dicyandiamine-triethylenetetramine polycondensation Materials such as polycondensates containing tertiary nitrogen or quaternary nitrogen; cationic surfactants, anionic surfactants, amphoteric surfactants, glycol stabilizers and other component stabilizers. In addition, when the other components are added, the concentration of the other components is usually about 0.001 g / L to 5 g / L.

The etching solution can be easily prepared by dissolving the above components in water. The water is preferably water from which ionic substances and impurities have been removed, and for example, ion-exchanged water, pure water, ultrapure water, and the like are preferred.

The above-mentioned etching solution may be prepared such that each component has a predetermined concentration during use, or a concentrated solution may be prepared in advance and used immediately after dilution. The method of using the etching solution is not particularly limited. In order to effectively suppress lateral etching, it is preferable to perform etching using spraying as described later. In addition, the temperature of the etching solution during use is not particularly limited, and it is preferably used at 20 ° C to 55 ° C in order to effectively suppress lateral etching from the viewpoint of maintaining high productivity.

The replenishing solution of the present invention is added to the etching solution when the etching solution of the present invention is used continuously or repeatedly, and contains the above-mentioned heteroaromatic compound (A) having a five-membered ring, and the above is selected from the group having a five-membered ring to An aqueous solution of one or more compounds from the group consisting of a six-membered heteroaromatic compound (B1) and the alkanolamine (B2). Each component in the replenishment liquid is the same as a component that can be blended into the etching solution of the present invention. By adding the replenishing liquid to ensure that the respective component ratios of the etchant are appropriate, the efficacy of the etchant of the present invention can be stably maintained.

In addition, the replenishment solution of the present invention may contain an acid such as hydrochloric acid in a range of a concentration not exceeding 360 g / L. In addition, the replenishment liquid may contain an oxidizing metal ion such as copper chloride in a range of not more than 14 g / L in terms of copper ion concentration. In addition, in the replenishing liquid, other components may be added to the etching liquid in addition to the above-mentioned components. Moreover, these components which may be contained in the said replenishment liquid may not be contained in the said replenishment liquid, and may be directly added to the etchant of this invention when using the etchant of this invention continuously or repeatedly.

The concentration of each component in the replenishment solution is appropriately set according to the concentration of each component in the etching solution. From the viewpoint of stably maintaining the efficacy of the above-mentioned etching solution of the present invention, it is preferable that the above-mentioned The total concentration of the aromatic compound (A) and one or more compounds selected from the group consisting of the heteroaromatic compound (B1) having a 5- to 6-membered ring and the alkanolamine (B2) is 0.01g / L to 30g / L.

The method of forming a copper wiring of the present invention etches a portion of a copper layer that is not covered by a resist, and the method of forming the copper wiring is characterized in that the etching solution of the present invention is used for etching. Therefore, as described above, the side etching has a high suppression effect and can form an excellent fine pattern of copper wiring. In the copper wiring forming step using the copper wiring forming method of the present invention, when the etching solution of the present invention is used continuously or repeatedly, it is preferable to perform the etching while adding the replenishing solution of the present invention. The reason for this operation is to ensure that the respective component ratios of the etching solution are appropriate, so that the efficacy of the etching solution of the present invention can be stably maintained.

In the method for forming a copper wiring of the present invention, it is preferable to spray the etching solution on a portion of the copper layer that is not covered by the resist by spraying. The reason for this operation is that the side etching can be effectively suppressed. In spraying, the nozzle is not particularly limited, and a fan nozzle, a dense conical nozzle, a two-fluid nozzle, or the like can be used.

When etching is performed by spraying, the spraying pressure is preferably 0.04 MPa or more, and more preferably 0.08 MPa or more. When the injection pressure is 0.04 MPa or more, a protective film can be formed on the side surface of the copper wiring with an appropriate thickness. Thereby, the side etching can be effectively prevented. In addition, from the viewpoint of preventing damage to the resist, the above-mentioned ejection pressure is preferably 0.30 MPa or less.

    [Example]    

Next, examples of the present invention and comparative examples will be described. The present invention is not limited to the examples described below.

Each etching solution having the composition shown in Tables 1 to 2 was prepared, and etching was performed under conditions described later, and each item was evaluated by an evaluation method described later. In each of the etching solutions having the compositions shown in Tables 1 to 2, the remainder was ion-exchanged water. The concentrations of hydrochloric acid shown in Tables 1 to 2 are concentrations in terms of hydrogen chloride.

(Test substrate used)

A copper / polyimide laminate having a copper layer thickness of 8 μm (produced by Toray Advanced Film, trade name “PI-38N-CCS-08EO”) was prepared, and a photolithography method (photoresist ("PMER-P-RZ30" manufactured by Tokyo Induction)) A resist pattern is formed on the copper layer. Regarding the resist pattern, a photoresist pattern in which a 20 μm pitch pattern region with a thickness of about 4 μm and a line / gap = 13 μm / 7 μm and a 40 μm pitch pattern region with a line / gap = 22 μm / 18 μm was prepared.

(Etching conditions)

Etching was performed using a fan nozzle (produced by Ikeuchi (IKEUCIH), trade name "ISVV9020") at a spray pressure of 0.18 MPa and a processing temperature of 35 ° C. Regarding the processing time, in the case of a pitch of 20 μm, it is set such that the bottom width of the copper wiring becomes 8 μm to 15 μm. The processing time at this time is shown in Tables 1 to 2. Among them, only Comparative Example 8 was treated with an injection pressure of 0.12 MPa. After the etching, the substrate was washed with water, dried, and evaluated as shown below.

(Evaluation of fine patterns)

For each test substrate subjected to the etching treatment, hydrochloric acid (hydrogen chloride concentration: 7% by weight) was used, and the protective film was removed by using a fan nozzle (produced by Ikeuchi (IKEUCIH) Co., Ltd .: ISVV9020) at a spray pressure of 0.15 MPa and a processing time of 40 seconds. The resist was immersed in acetone for 20 seconds (or 60 seconds in a 3% by weight aqueous sodium hydroxide solution). Then, a part of each test substrate was cut, and this part was embedded in a cold-embedded resin, and the grinding process was performed so that the cross section of a wiring could be observed, and the sample for cross-section observation was produced. For the cross-sectional observation of the wiring, an image was taken using an optical microscope, and the top width and the bottom width of the wiring were measured. At this time, a measurement of n = 2 or more is performed, and the top width and the bottom width are set as an average value. In addition, B-T in the table is a value of the bottom width-top width of the copper wiring. In addition, in the comparative example, "-" is shown when the bottom width cannot be measured and the bottom width cannot be measured. In the column of the fine pattern (fine Pt) in the table, a case where the BT value of the 20 μm pitch pattern region with a line / gap of 13 μm / 7 μm is less than 2 μm is evaluated as ○, and a case where the BT value is 2 μm or more, or The case where the bottom width cannot be measured is evaluated as ×.

In Tables 1 and 2, the dicyandiamine-formaldehyde polycondensate is a product of "Unisense KHF10P" manufactured by Senka Corporation.

As shown in Table 1, according to the embodiment of the present invention, the value of the B-T is less than 2 μm, and it is understood that an excellent fine pattern can be formed. On the other hand, as shown in Table 2, the comparative example obtained a worse result than the example. From this result, it is understood that according to the present invention, it is possible to obtain an etching solution with high suppression effect of lateral etching and excellent pattern formation of copper wiring.

Claims (10)

An etching solution is a copper etching solution; the aforementioned etching solution contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a five-membered ring, and a heteroaromatic compound selected from the group consisting of a five-membered ring to a six-membered ring An aqueous solution of one or more compounds in the group consisting of a compound (B1) and an alkanolamine (B2); the aforementioned heteroaromatic compound (A) having a five-membered ring has no hydroxyalkyl group and has one or more A heteroaromatic compound having a nitrogen atom as a heteroatom constituting a ring; the aforementioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring is a heteroatom having one or more nitrogen atoms and has a carbon number Heteroaromatic compounds substituted with 1 to 5 hydroxyalkyl substituents; the aforementioned alkanolamine (B2) is a compound having the general formula R ¹ -N (R ² ) -R ³ , and in the general formula, R ¹ and R ² independently represent an alkyl group or a hydroxyalkyl group having 1 to 8 carbon atoms, R ³ represents a hydrogen atom, an alkyl group or a hydroxyalkyl group having ¹ to 8 carbon atoms, and at least one of R ¹ to R ³ Is the aforementioned hydroxyalkyl group.     The etching solution according to claim 1, wherein the acid is hydrochloric acid.         The etching solution according to claim 1 or 2, wherein the oxidizing metal ion is a copper ion.         The etching solution according to claim 1 or 2, wherein the heteroaromatic compound (A) having a five-membered ring is selected from the group consisting of an imidazole compound, a pyrazole compound, a triazole compound, and a tetrazole compound. More than one compound.         The etching solution according to claim 1 or 2, wherein the heteroaromatic compound (B1) having a five-membered ring to a six-membered ring has only one or more nitrogen atoms as a heteroatom constituting the ring.         The etching solution according to claim 1 or 2, wherein the aforementioned heteroaromatic compound (B1) having a five-membered ring to a six-membered ring is one or more members selected from the group consisting of: Compound (b1-0) having an aromatic five-membered ring as a heterocyclic ring, compound (b1-1) containing only a heteroaromatic six-membered ring in the molecule, and a fused ring containing a heteroaromatic six-membered ring and a hetero five-membered ring in the molecule (b1-2), and a compound (b1-3) in which a heteroaromatic six-membered ring and a hetero five-membered ring are connected through a single bond or a divalent linking group.         The etching solution according to claim 1 or 2, wherein the compound is one or more compounds selected from the group consisting of a heteroaromatic compound (B1) having a five-membered ring to a six-membered ring and an alkanolamine (B2). The concentration is 0.15 g / L or more and 30 g / L or less.         The etching solution according to claim 1 or 2, wherein the heteroaromatic compound (A) having a five-membered ring and the heteroaromatic compound (B1) having a five-membered ring to a six-membered ring are selected from the alkanol The weight ratio [(A) / ((B1) + (B2))] of one or more compounds in the group composed of the amine (B2) is 0.001 or more and 30 or less.         A replenisher added to the etchant when the etchant according to any one of claims 1 to 8 is used continuously or repeatedly; the replenisher is a heteroaromatic compound (A) containing the five-membered ring And an aqueous solution of one or more compounds selected from the group consisting of a heteroaromatic compound (B1) having a five-membered ring to a six-membered ring and the alkanolamine (B2).         A method for forming a copper wiring, etching a portion of a copper layer that is not covered by a resist; and the method for forming the copper wiring, using an etching solution according to any one of claims 1 to 8 for etching .