CN113179590A

CN113179590A - Etching solution, replenishment solution, and method for forming copper wiring

Info

Publication number: CN113179590A
Application number: CN202110081388.2A
Authority: CN
Inventors: 浜口仁美; 仁顷丈二郎
Original assignee: MEC Co Ltd
Current assignee: MEC Co Ltd
Priority date: 2020-01-24
Filing date: 2021-01-21
Publication date: 2021-07-27
Also published as: JP7129711B2; KR20210095806A; JP2021116449A; TW202136581A; TWI799783B; JP2022008849A

Abstract

The present application relates to an etching solution, a replenishment solution, and a method for forming copper wiring. The present invention is an etching solution for copper, comprising: an acid, an oxidizing metal ion, an aromatic heterocyclic compound (A) having a five-membered ring, which is an aromatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, which is an aliphatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, and a cationic polymer containing tertiary nitrogen or quaternary nitrogen in the molecule. The etching solution can form a fine pattern in a fine pitch pattern region where fine portions and coarse portions are present in a mixed manner.

Description

Etching solution, replenishment solution, and method for forming copper wiring

Technical Field

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

Background

In the production of printed wiring boards, when copper wiring patterns are formed by photolithography, an etching solution such as an iron chloride-based etching solution, a copper chloride-based etching solution, or an alkaline etching solution is generally used. The use of these etching solutions means that copper under the resist dissolves from the side of the wiring pattern, which is called side etching. That is, a portion which is originally intended to be not removed by etching by covering the resist (i.e., a copper wiring portion) is removed by the etching liquid, so that a phenomenon occurs in which the width of the copper wiring is tapered from the bottom to the top. Particularly, when the copper wiring pattern is fine, such side etching must be minimized. In order to suppress the side etching, an etching solution in which an azole compound, which is an aromatic heterocyclic compound having a five-membered ring, is blended has been proposed (patent documents 1 to 4). In addition, in order to suppress side etching, an etching solution prepared with an aliphatic heterocyclic compound having five to seven membered rings has also been proposed (patent document 5).

[ background Art document ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2005-330572

[ patent document 2] Japanese patent laid-open publication No. 2009-221596

[ patent document 3] Japanese patent application laid-open No. 2013-104104

[ patent document 4] Japanese patent application laid-open No. 2018-193602

[ patent document 5] Japanese patent application laid-open No. 2014-224303

Disclosure of Invention

[ problems to be solved by the invention ]

On the other hand, an etching solution is required to have an effect of suppressing side etching and to form a fine pattern of copper wiring excellently in the market. Although a certain side etching suppressing effect can be expected with the etching solution disclosed in the above-mentioned patent document, the etching solution disclosed in patent document 4, which is judged to be high-performance, specifically discloses the following: successfully forming a fine pattern in a pitch pattern in which a 20 μm pitch pattern region (fine feature) having a line width/line pitch (line/space) of 13 μm/7 μm and a 40 μm pitch pattern region (roughness) having a line width/line pitch of 22 μm/18 μm are mixed; however, the method forms a fine pattern in a finer (narrow) pitch pattern region than it.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an etching solution and a supply solution thereof, which are excellent for forming a fine pattern in a fine pitch pattern region where a fine portion and a coarse portion are present in a mixed state, and a method for forming a copper wiring.

[ means for solving the problems ]

The present invention relates to an etching solution for copper, comprising: an acid, an oxidizing metal ion, an aromatic heterocyclic compound (A) having a five-membered ring, which is an aromatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, which is an aliphatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, and a cationic polymer containing tertiary nitrogen or quaternary nitrogen in the molecule.

The present invention relates to a supply solution to be added to an etching solution when the etching solution is used continuously or repeatedly, the supply solution being an aqueous solution containing: the aromatic heterocyclic compound (A) having a five-membered ring is an aromatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, and the aliphatic heterocyclic compound (B) having a five-to seven-membered ring is an aliphatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom.

The present invention relates to a method for forming a copper wiring by etching a portion of a copper layer not covered with a resist and etching the portion using the etching solution.

[ Effect of the invention ]

The etching solution of the present invention comprises: an acid, an oxidizing metal ion, an aromatic heterocyclic compound (A) having a five-membered ring, which is an aromatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, which is an aliphatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, and a cationic polymer containing tertiary nitrogen or quaternary nitrogen in the molecule. The etching solution of the present invention can form a uniform coating film in a fine pitch pattern region where fine portions and coarse portions are present in a mixed manner, thereby suppressing side etching and forming a fine pattern having excellent linearity. Therefore, the etching solution of the present invention can be used for forming a copper wiring pattern on a copper surface provided with a resist.

The etching solution of the present invention can form a fine pattern in a fine pitch pattern region where fine portions and coarse portions are present in a mixed state, and can form a coarse pattern in a favorable manner. In general, since the flow rate of the etching liquid is different between the fine portion and the coarse portion, there is a tendency that a difference in film formation and etching in the depth direction is likely to occur. For example, in a rough portion having a high flow rate, a coating film is not easily formed on the bottom, and therefore, shrinkage (an inverted trapezoidal shape) is easily generated on the bottom of the rough pattern. In the case where such a bottom portion is shrunk, the bottom portion width cannot be observed from the upper portion of the substrate, and therefore, there is a risk that: when the product management is difficult, or when pressure is applied to the top portion during mounting, for example, the corner portion of the top portion is broken, which may cause mounting abnormality or generation of foreign matter. The etching solution of the present invention is useful because it has no difference in the etching properties between the fine portion and the coarse portion (the fine pattern and the coarse pattern have substantially the same shape), and therefore the above-mentioned problems can be avoided.

Detailed Description

Etching solution for copper

The copper etchant of the present invention comprises: an acid, an oxidizing metal ion, an aromatic heterocyclic compound (A) having a five-membered ring, which is an aromatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, which is an aliphatic heterocyclic compound having one or more nitrogen atoms as a ring-constituting heteroatom, and a cationic polymer containing tertiary nitrogen or quaternary nitrogen in the molecule. The "copper" in the copper etchant of the present invention may be copper or a copper alloy.

< acid >)

The acid of the present invention may be selected as appropriate 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 acids, hydrochloric acid is preferable from the viewpoint of stability of etching rate and dissolution stability of copper. At least one of the acids may be used, or two or more of them may be used in combination.

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

< oxidizing metal ion >

The oxidizing metal ion of the present invention is not particularly limited as long as it is a metal ion capable of oxidizing metallic copper, and examples thereof include divalent copper ions and trivalent iron ions. From the viewpoint of suppressing the side etching and the viewpoint of stability of the etching rate, it is preferable to use divalent copper ions as the oxidizing metal ions. At least one oxidizing metal ion may be used, or two or more oxidizing metal ions may be used in combination.

The oxidizing metal ion may be contained in the etching solution by formulating an oxidizing metal ion source. For example, when a cupric ion source is used as the oxidizing metal ion source, specific examples thereof include: copper chloride, copper sulfate, copper bromide, copper salts of organic acids, copper hydroxide, and the like. For example, when a ferric ion source is used as the oxidizing metal ion source, specific examples thereof include: ferric chloride, ferric bromide, ferric iodide, ferric sulfate, ferric nitrate, ferric salts of organic acids, and the like.

The concentration of the oxidizing metal ions is preferably 10 to 300g/L, more preferably 10 to 250g/L, still more preferably 15 to 220g/L, and still more preferably 20 to 200 g/L. When the concentration of the oxidizing metal ion is 10g/L or more, the etching rate becomes high, and thus copper can be etched quickly. Further, when the concentration of the oxidizing metal ion is 300g/L or less, the dissolution stability of copper can be maintained.

< aromatic heterocyclic compound (A) having five-membered ring >

The aromatic heterocyclic compound (a) having a five-membered ring of the present invention is an aromatic heterocyclic compound having one or more nitrogen atoms as a hetero atom constituting the ring. At least one aromatic heterocyclic compound (A) having a five-membered ring may be used, or two or more of them may be used in combination.

The aromatic heterocyclic compound (a) having a five-membered ring preferably has only nitrogen as a hetero atom constituting the ring from the viewpoint of structural stability and solubility in an acidic liquid. Examples of the aromatic heterocyclic compound (a) having a five-membered ring include azole compounds such as an imidazole compound having an imidazole skeleton, a pyrazole compound having a pyrazole skeleton, a triazole compound having a triazole skeleton, and a tetrazole compound having a tetrazole skeleton.

Examples of the imidazole compound include imidazoles such as imidazole, 2-methylimidazole, 2-undecyl-4-methylimidazole and 2-phenylimidazole, benzimidazoles such as benzimidazole, 2-methylbenzimidazole, 2-undecylbenzimidazole, 2-phenylbenzimidazole and 2-mercaptobenzimidazole, and the like. Among them, benzimidazole is preferable.

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

Examples of the triazole compound include 1,2, 3-triazole, 1,2, 4-triazole, 5-phenyl-1, 2, 4-triazole, 5-amino-1, 2, 4-triazole, benzotriazole, 1-methyl-benzotriazole, and methylbenzotriazole. Among them, benzotriazole is preferable.

Examples of the tetrazole compound include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-mercapto-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 1-cyclohexyl-5-mercapto-1H-tetrazole, 5' -bi-1H-tetrazole, and metal salts such as ammonium salts, Na salts, Zn salts, Ca salts, and K salts thereof.

Among the azole compounds, from the viewpoint of a high side etching (undercut) inhibitory effect, a tetrazole compound is preferable, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5' -bi-1H-tetrazole, and an ammonium salt or a metal salt thereof are more preferable, and 1H-tetrazole, 5-methyl-1H-tetrazole, 5-amino-1H-tetrazole, and an ammonium salt or a metal salt thereof are further preferable. It is presumed that these tetrazole compounds can form a thin and uniform protective film on the side surface from the top of the conductor pattern.

The concentration of the aromatic heterocyclic compound (A) having a five-membered ring is preferably 0.1 to 50g/L, more preferably 0.1 to 15g/L, and further preferably 0.2 to 10 g/L. If the concentration of the aromatic heterocyclic compound (A) having a five-membered ring is 0.1g/L or more, the side etching (particularly, the reduction of the top width) can be suppressed reliably. On the other hand, when the concentration of the aromatic heterocyclic compound (a) having a five-membered ring is 50g/L or less, the etching rate can be prevented from being lowered, and the portion to be etched can be reliably etched, so that the occurrence of short circuit (insulation failure) can be prevented.

< aliphatic heterocyclic Compound (B) having five-to seven-membered Ring >

The aliphatic heterocyclic compound (B) having five to seven membered rings of the present invention is an aliphatic heterocyclic compound having one or more nitrogen atoms as a hetero atom constituting a ring. At least one kind of the aliphatic heterocyclic compound (B) having five to seven membered rings may be used, or two or more kinds may be used in combination.

The aliphatic heterocyclic compound (B) having five to seven membered rings preferably has only nitrogen as a heteroatom constituting a ring in order to suppress side etching without lowering the linearity of copper wiring. In addition, the aliphatic heterocyclic compound (B) having five to seven membered rings is preferably an aliphatic heterocyclic compound having 3 or less ring-constituting nitrogens from the viewpoint of stability in the etching solution.

Specific examples of the aliphatic heterocyclic compound include: a tetrahydropyrrole compound having a tetrahydropyrrole skeleton, a piperidine compound having a piperidine skeleton, a piperazine compound having a piperazine skeleton, a homopiperazine compound having a homopiperazine skeleton, a hexahydro-1, 3, 5-triazine compound having a hexahydro-1, 3, 5-triazine skeleton, and the like. In the above-mentioned compounds, the aliphatic heterocyclic ring may be substituted with a substituent such as an amino group, an alkyl group, an aralkyl group, an aryl group, a nitro group, a nitroso group, a hydroxyl group, a carboxyl group, a carbonyl group, an alkoxy group, a halogen group, an azo group, a cyano group, an imino group, a phosphino group, a thiol group, or a sulfo group.

The above-mentioned pyrrolidine compound is not particularly limited as long as it has a pyrrolidine skeleton, and examples thereof include a pyrrolidine compound represented by the following formula (I).

(in the general formula (I), R¹～R⁵Each independently represents hydrogen, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms other than the amino group-containing substituent. These substituents may bond to each other to form a ring structure).

The amino group represents-NH₂and-NHR, and-NRR ', wherein R, R ' independently represents a hydrocarbon derivative group having 1 to 10 carbon atoms, and R ' may be bonded to each other to form a saturated ring structure. The amino group-containing substituent is any of a substituent comprising an amino group and a substituent in which a part of hydrogen in a hydrocarbon derivative group having 1 to 10 carbon atoms is substituted with an amino group. From the viewpoint of effectively suppressing the side etching and further improving the linearity of the copper wiring, a substituent group including an amino group or a substituent group including an amino group including carbon, hydrogen, and nitrogen is preferable. The same applies to the following amino group and amino group-containing substituent.

The hydrocarbon derivative group is a group in which a part of carbon or hydrogen in the hydrocarbon group is substituted with another atom or substituent. Examples of the hydrocarbon derivative include methyl, ethyl, propyl, butyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, aryl, acetyl, phenyl, hydroxyethoxymethyl, hydroxyethoxyethyl, and hydroxyethoxypropyl, and a hydrocarbon derivative composed of carbon and hydrogen is preferable from the viewpoint of effectively suppressing side etching and further improving the linearity of copper wiring. The same applies to the following hydrocarbon derivatives.

Specific examples of the above-mentioned tetrahydropyrrole compound include: tetrahydropyrrole, 1- (2-hydroxyethyl) tetrahydropyrrole, indoline, 1-isopropyl-3-hydroxytetrahydropyrrole, 1, 2-cyclohexanedicarboximide, 1-butyltetrahydropyrrole, 1-ethyltetrahydropyrrole, 2- (2-hydroxyethyl) -1-methyltetrahydropyrrole, 2-methyltetrahydropyrrole, 1- (2-hydroxyethyl) tetrahydropyrrole, 1- (3-aminopropyl) tetrahydropyrrole, 1- (2-aminoethyl) tetrahydropyrrole, 3-aminotetrahydropyrrole, 2-aminomethyl-1-ethyltetrahydropyrrole, 2- (2-aminoethyl) -1-methyltetrahydropyrrole, 3- (dimethylamino) tetrahydropyrrole, 3- (methylamino) tetrahydropyrrole, indoline, 1-isopropyl-3-hydroxytetrahydropyrrole, 1, 2-cyclohexanedicarboximide, 1- (2-hydroxyethyl) tetrahydropyrrole, 1- (3-aminopropyl) tetrahydropyrrole, 1- (2-aminoethyl) tetrahydropyrrole, 3- (dimethylamino) tetrahydropyrrole, 3- (methylamino) tetrahydropyrrole, 2-methyl-ol, 2-amino-methyl-pyrrolidine, 2-amino-methyl-1-tetrahydropyrrole, 2-amino-methyl-2-ethyl-1-methyl tetrahydropyrrole, 2-methyl, 1- (2-Tetrahydropyrrolylmethyl) tetrahydropyrrole, 3- (diethylamino) tetrahydropyrrole, 1' -dimethyl-3-aminotetrahydropyrrole, 3- (ethylamino) tetrahydropyrrole, 1-methyl-2- (1-piperidinylmethyl) tetrahydropyrrole, 4- (1-tetrahydropyrrolyl) piperidine, 3- (N-acetyl-N-methylamino) tetrahydropyrrole, 3- (N-acetyl-N-ethylamino) tetrahydropyrrole, 2-tetrahydropyrrole carboxamide, 3-acetamidotetrahydropyrrole, 1-ethyl-2-tetrahydropyrrole carboxamide, 3-amino-1- (tert-butoxycarbonyl) tetrahydropyrrole, beta-glucosidase, and combinations thereof, 3- (tert-butoxycarbonylamino) tetrahydropyrrole, 1-amino-2- (methoxymethyl) tetrahydropyrrole, 1-benzyl-3-aminotetrahydropyrrole, 1-benzyl-3- (dimethylamino) tetrahydropyrrole, 1-benzyl-3- (methylamino) tetrahydropyrrole, 1-benzyl-3- (ethylamino) tetrahydropyrrole, 3, 4-diamino-1-benzyltetrahydropyrrole, 1-benzyl-3-acetamide tetrahydropyrrole, (1s,6s) -2, 8-diazabicyclo [4.3.0] nonane, and the like.

The piperidine compound is not particularly limited as long as it has a piperidine skeleton, and examples thereof include a piperidine compound represented by the following formula (II).

(in the general formula (II), R⁶～R¹¹Each independently represents hydrogen, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms other than the amino group-containing substituent. These substituents may bond to each other to form a ring structure).

Specific examples of the piperidine compound include: piperidine, 1-methylpiperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 3, 5-dimethylpiperidine, 2-ethylpiperidine, 4-piperidinecarboxylic acid, 1,2,3, 4-tetrahydroquinoline, decahydroisoquinoline, 2, 6-dimethylpiperidine, 2-piperidinemethanol, 3-piperidinemethanol, 4-piperidinemethanol, 2,6, 6-tetramethylpiperidine, 4-aminopiperidine, 1-aminopiperidine, 3-aminopiperidine, 4- (aminomethyl) piperidine, 4-amino-1-methylpiperidine, 2- (aminomethyl) piperidine, 3- (aminomethyl) piperidine, 4-piperidinecarboxamide, 2-piperidinecarboxamide, 3-piperidinecarboxamide, 2-piperidin, 1- (2-aminoethyl) piperidine, 4-acetamidopiperidine, 3-acetamidopiperidine, 4-amino-1-isopropylpiperidine, 1- (3-aminopropyl) -2-methylpiperidine, 4-amino-2, 2,6, 6-tetramethylpiperidine, 2 '-bipiperidine, 4' -bipiperidine, 4-piperidinopiperidine, 4-amino-1-piperidinecarboxylic acid ethyl ester, 4-amino-1-benzylpiperidine, 4- (2-aminoethyl) -1-benzylpiperidine, 4-acetamidopiperidine-1-benzylpiperidine and the like.

The piperazine compound is not particularly limited as long as it has a piperazine skeleton, and examples thereof include piperazine compounds represented by the following formula (III).

(in the general formula (III), R¹²～R¹⁷Each independently represents hydrogen, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms other than the amino group-containing substituent. These substituents may bond to each other to form a ring structure).

Specific examples of the piperazine compound include: piperazine, 1-methylpiperazine, 2-methylpiperazine, 1-allylpiperazine, 1-isobutylpiperazine, 1-hydroxyethoxyethylpiperazine, 1-phenylpiperazine, 1-aminopiperazine, 1-aminoethylpiperazine, N- (2-aminoethylpiperazine), 1-amino-4-methylpiperazine, 1-ethylpiperazine, 1-piperazineethanol, 1-piperazinecarboxylic acid ethyl ester, 1-formylpiperazine, 1-propylpiperazine, 1-acetylpiperazine, 1-isopropylpiperazine, 1-cyclopentylpiperazine, 1-cyclohexylpiperazine, 1- (2-methoxyethyl) piperazine, 1-piperonylpiperazine, 1- (diphenylmethyl) piperazine, 2-piperazinone, piperazine, and piperazine, and piperazine 1, 4-dimethylpiperazine, 1-methyl-3-phenylpiperazine, 1, 4-bis (3-aminopropyl) piperazine, 1- (2-dimethylaminoethyl) -4-methylpiperazine, 1- (2-aminoethyl) piperazine, 1, 4-bis (3-aminopropyl) piperazine, 2, 5-dimethylpiperazine, 2, 6-dimethylpiperazine, 1, 4-diformylpiperazine, 1- (4-aminophenyl) -4-methylpiperazine, 1, 4-diacetyl-2, 5-piperazinedione, 1-methyl-4- (1,4' -bipiperidin-4-yl) piperazine, 1- (4-aminophenyl) -4- (4-methoxyphenyl) piperazine, 1, 4-aminopropy-l-4-ethylpiperazine, 1, 4-aminopropy-l-piperazine, 1, 4-bis (3-aminopropyl) piperazine, 1, 4-dimethylpiperazin-2-one, 1, 4-diethylpiperazin-2-one, 1, 4-dimethylpiperazin-2, 3-dione, 2-piperazinecarboxylic acid, triethylenediamine, and the like.

The homopiperazine compound is not particularly limited as long as it has a homopiperazine skeleton, and examples thereof include homopiperazine compounds represented by the following formula (IV).

(in the general formula (IV), R¹⁸～R²⁴Each independently represents hydrogen, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms other than the amino group-containing substituent. These substituents may bond to each other to form a ring structure).

Specific examples of the homopiperazine compound include: homopiperazine, 1-methylpiperazine, 1-formylhomopiperazine, 1, 4-dimethylpiperazine, 4-methyl-1-homopiperazine dithiocarboxylic acid, 1-acetylhomopiperazine, 1-butyrylpiperazine and the like.

The hexahydro-1, 3, 5-triazine compound is not particularly limited as long as it has a hexahydro-1, 3, 5-triazine skeleton, and examples thereof include hexahydro-1, 3, 5-triazine compounds represented by the following formula (V).

(in the general formula (V), R²⁵～R³⁰Each independently represents hydrogen, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms other than the amino group-containing substituent. These substituents may bond to each other to form a ring structure).

Specific examples of the hexahydro-1, 3, 5-triazine compound include: hexahydro-1, 3, 5-triazine, hexahydro-1, 3, 5-trimethyl-1, 3, 5-triazine, hexahydro-2, 4, 6-trimethyl-1, 3, 5-triazine, hexahydro-1, 3, 5-tris (3-dimethylaminopropyl) -1,3, 5-triazine, hexahydro-1, 3, 5-tripropyl-1, 3, 5-triazine, hexahydro-1, 3, 5-triethyl-1, 3, 5-triazine, hexahydro-1, 3, 5-triisopropyl-1, 3, 5-triazine, hexahydro-1, 3, 5-tribenzyl-1, 3, 5-triazine, hexahydro-1, 3, 5-tris (2-hydroxyethyl) -1,3, 5-triazine, hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine, hexahydro-2, 4, 6-trimethyl-1, 3, 5-trinitro-1, 3, 5-triazine, hexahydro-1, 3, 5-triacryloyl-1, 3, 5-triazine, hexamethylenetetramine, and the like.

The concentration of the aliphatic heterocyclic compound (B) having five to seven membered rings is preferably 0.01 to 10g/L, more preferably 0.02 to 5g/L, and further preferably 0.05 to 3g/L, from the viewpoint of improving the ability to form a fine pattern in a fine pitch pattern region where fine parts and coarse parts are present together.

< cationic Polymer containing Tertiary Nitrogen or Quaternary Nitrogen >

Known examples of the cationic polymer containing a tertiary nitrogen or quaternary nitrogen of the present invention can be used, and examples thereof include: dicyanamide-based cationic polymers such as dicyandiamide-polyalkylene polyamine polycondensates, e.g., dicyandiamide-diethylenetriamine polycondensates, dicyandiamide-formaldehyde polycondensates, and dicyandiamide-triethylenetetramine polycondensates; polyallylamine-based cationic polymers such as polyallylamine, allylamine-dimethylallylamine copolymers, diallyl dimethylammonium chloride polycondensates, diallyl amine acetate-sulfur dioxide copolymers, diallyl methylethylammonium ethylsulfate-sulfur dioxide copolymers, polyallylamine amide sulfate, allylamine acetate-diallyl amine acetate copolymers, methyldiallylamine amide sulfate polymers, and diallyl amine amide sulfate-maleic acid copolymers; and polycondensates of aliphatic monoamines such as dimethylamine-epichlorohydrin polycondensates and epihalohydrin compounds. Among them, from the viewpoint of forming a copper wiring excellent in linearity, the cationic polymer containing tertiary nitrogen or quaternary nitrogen is preferably a dicyandiamide-polyalkylene polyamine polycondensate such as a dicyandiamide-diethylenetriamine polycondensate, a dicyandiamide-formaldehyde polycondensate, a dicyandiamide-triethylenetetramine polycondensate, or a diallyldimethylammonium chloride polycondensate. The cationic polymer containing a tertiary nitrogen or quaternary nitrogen may be used in combination of two or more kinds.

The concentration of the cationic polymer containing tertiary nitrogen or quaternary nitrogen is preferably 0.001 to 10g/L, more preferably 0.005 to 5g/L, and even more preferably 0.01 to 2g/L, from the viewpoint of improving the ability to form fine patterns in fine pitch pattern regions where fine parts and coarse parts are present together.

< glycol ethers and/or glycols >

The etching solution of the present invention preferably contains glycol ethers and/or glycols from the viewpoint that a fine pattern can be formed excellently in a fine pitch pattern region where fine portions and coarse portions are present in a mixed state, and a coarse pattern can also be formed excellently. Two or more of the above-mentioned glycol ethers and/or glycols may be used in combination.

As the glycol ether, known glycol ethers can be used, and examples thereof include: ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, and the like. Among them, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and dipropylene glycol monomethyl ether are preferable.

As the glycols, known glycols can be used, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, methyl propylene glycol, dimethyl diethylene glycol, methyl ethyl diethylene glycol, methyl dipropylene glycol, methyl tripropylene glycol, polyethylene glycol, and polypropylene glycol. Among them, diethylene glycol, methyl propylene glycol, methyl dipropylene glycol, and methyl ethyl diethylene glycol are preferable.

The concentration of the glycol ether and/or glycol is preferably 0.01 to 30g/L, more preferably 0.1 to 10g/L, and still more preferably 0.1 to 5g/L, from the viewpoint of improving the ability to form fine patterns and coarse patterns in fine pitch pattern regions where fine portions and coarse portions are present together.

In addition to the above components, other components may be added to the etching solution of the present invention to the extent that the effects of the present invention are not impaired. As the other ingredients, for example, there may be added: aliphatic acyclic compounds such as diethylenetriamine, triethylenetetramine, tetraethylpentamine (tetraethylenepentamine), and pentaethylenehexamine; cationic surfactant, anionic surfactant, amphoteric surfactant, etc. When the other components are added, the concentration is usually about 0.001 to 5 g/L.

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

The etching solution may be prepared by mixing each component so as to have a specific concentration at the time of use, or may be prepared in advance as a concentrated solution and diluted immediately before use. The method of using the etching solution is not particularly limited, and in order to effectively suppress the side etching, it is preferable to perform the etching using a spray gun as described later. The temperature of the etching solution during use is not particularly limited, and it is preferably 20 to 55 ℃ in order to effectively suppress side etching in view of maintaining high productivity.

The replenishment solution of the present invention is a replenishment solution to be added to the etching solution of the present invention when the etching solution is used continuously or repeatedly, and the replenishment solution is an aqueous solution containing the following compounds: the aromatic heterocyclic compound (A) having a five-membered ring, the aliphatic heterocyclic compound (B) having a five-to seven-membered ring, and the cationic polymer containing a tertiary nitrogen or a quaternary nitrogen in the molecule. The components in the replenishment solution are the same as those of the etching solution of the present invention. By adding the replenishment liquid, the composition ratio of the etching liquid is maintained at an appropriate level, and therefore the effects of the etching liquid of the present invention can be stably maintained.

The replenishing solution of the present invention may contain an acid such as hydrochloric acid. The replenishment solution may contain an oxidizing metal ion such as copper dichloride. In addition to the above components, other components to be added to the etching solution may be added to the replenishment solution. In addition, the components that may be contained in the supply solution may be added directly to the etching solution of the present invention, instead of being contained in the supply solution, when the etching solution of the present invention is used continuously or repeatedly.

The method for forming a copper wiring of the present invention is a method for etching a portion of a copper layer not covered with a resist, and is characterized in that etching is performed using the etching solution of the present invention. As a result, as described above, an excellent fine pattern of copper wiring can be formed in the fine pitch pattern region where the fine portion and the coarse portion are present together. 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 continuously or repeatedly used, it is preferable to perform etching while adding the supply solution of the present invention. This is because the composition ratio of the etching solution is maintained at an appropriate level, and therefore the effects of the etching solution of the present invention can be stably maintained.

In the method for forming copper wiring of the present invention, it is preferable that the etching solution is sprayed to a portion of the copper layer not covered with the resist by a sprayer. This is because side etching can be effectively suppressed. When spraying, the nozzle is not particularly limited, and a fan nozzle, a solid cone nozzle, a two-fluid nozzle, or the like can be used.

In the case of etching with a sprayer, the spraying pressure is preferably 0.04MPa or more, and more preferably 0.08MPa or more. If the spraying pressure is 0.04MPa or more, a protective film having an appropriate thickness can be formed on the side surface of the copper wiring. This can effectively prevent side etching. In addition, the spraying pressure is preferably 0.40MPa or less from the viewpoint of preventing the resist from being damaged.

[ examples ]

Next, examples of the present invention and comparative examples are described together. In addition, the present invention should not be construed as being limited to the following examples.

Etching solutions having compositions shown in tables 1 to 2 were prepared, and etching was performed under the following conditions, and evaluation was performed for each item by the following evaluation method. In each of the etching solutions having the compositions shown in tables 1 to 2, the balance was ion-exchanged water. The concentrations of hydrochloric acid shown in tables 1 to 2 are the concentrations of hydrogen chloride.

(test substrate used)

A copper/polyimide laminate (trade name "PI-38N-CCS-08 EO", manufactured by Toray film processing) having a copper layer thickness of 8 μm was prepared, and a resist pattern was formed on the copper layer by photolithography (resist ("PMER-P-RZ 30", manufactured by Tokyo chemical Co., Ltd.). As for the resist pattern, a resist pattern was produced in which a pattern region (fine feature) having a 18 μm pitch having a thickness of about 4 μm and a line width/line pitch of 11 μm/7 μm and a pattern region (rough feature) having a 25 μm pitch having a line width/line pitch of 16 μm/9 μm were mixed.

(etching conditions)

The etching was carried out using a fan nozzle (trade name "ISVV 9020" manufactured by BATCH Co.) under a spray pressure of 0.20MPa and a treatment temperature of 35 ℃. The processing time is set to be 8 to 15 μm in width of the bottom of the copper wiring when the pitch is 18 μm. After etching, the substrate was washed with water, dried, and evaluated as follows.

(evaluation of Fine Pattern)

The resist was removed by immersing each of the test substrates subjected to the etching treatment in acetone for 20 seconds (or in a 3 wt% aqueous solution of sodium hydroxide for 60 seconds) while removing the protective film with hydrochloric acid (hydrogen chloride concentration: 7 wt%) by a fan nozzle (product name: ISVV9020, manufactured by intracell corporation) at a spray pressure of 0.15MPa for a treatment time of 40 seconds. Subsequently, a part of each test substrate was cut and embedded in the cold embedding resin, and polishing was performed so that the wiring cross section could be observed, thereby producing a sample for cross section observation. In 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, n is measured 2 or more times, and the top width and the bottom width are averaged. In addition, B-T in the table is a value of bottom width-top width of the copper wiring. In the fine section column of the table, the value of B-T in the 18 μm pitch pattern region having a line width/line pitch of 11 μm/7 μm is determined as 0 ≦ B-T ≦ 2 μm, and the other cases are determined as x. Regarding the linearity of the fine portion, the width of the bottom portion was measured at 50 degrees, the standard deviation thereof was calculated, and a case of 0.50 or less was judged as o (acceptable standard for linearity), and the other cases were judged as x. In the rough portion column, from the viewpoint that the bottom of the rough pattern is less likely to shrink, it is preferable that the value B-T in the pitch pattern region of 25 μm where the line width/line pitch is 19 μm/9 μm is 0 or more. Further, the difference in density is defined as a value obtained by subtracting B-T of the roughened portion from B-T of the fine portion, and the closer the value is to 0, the closer the difference in density is to 0, since it can be judged that there is no difference in etching properties between the fine portion and the roughened portion.

[ Table 1]

[ Table 2]

Claims

1. An etching solution for copper, characterized in that,

the etching solution comprises: an acid, an oxidizing metal ion, an aromatic heterocyclic compound (A) having a five-membered ring, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, and a cationic polymer containing tertiary nitrogen or quaternary nitrogen in the molecule,

the aromatic heterocyclic compound (A) having a five-membered ring is an aromatic heterocyclic compound having one or more nitrogen atoms as hetero atoms constituting the ring,

the aliphatic heterocyclic compound (B) having a five-to seven-membered ring is an aliphatic heterocyclic compound having one or more nitrogen atoms as a hetero atom constituting a ring.

2. The etching solution of claim 1, wherein the acid is hydrochloric acid.

3. The etching solution according to claim 1 or 2, wherein the oxidizing metal ions are divalent copper ions.

4. The etching solution according to claim 1 or 2, wherein the aromatic heterocyclic compound (A) having a five-membered ring is at least one compound selected from the group consisting of an imidazole compound, a pyrazole compound, a triazole compound, and a tetrazole compound.

5. The etching solution according to claim 1 or 2, wherein the aliphatic heterocyclic compound (B) having five to seven membered rings is one or more compounds selected from the group consisting of a tetrahydropyrrole compound, a piperidine compound, a piperazine compound, a homopiperazine compound, and a hexahydro-1, 3, 5-triazine compound.

6. The etching solution according to claim 1 or 2, comprising glycol ethers and/or glycols.

7. A replenishment solution which is added to an etching solution according to any one of claims 1 to 6 when the etching solution is continuously or repeatedly used,

the replenishing solution is an aqueous solution containing the following compounds: an aromatic heterocyclic compound (A) having a five-membered ring, an aliphatic heterocyclic compound (B) having a five-to seven-membered ring, and a cationic polymer containing a tertiary nitrogen or a quaternary nitrogen in the molecule,

8. A method for forming a copper wiring by etching a portion of a copper layer not covered with a resist,

etching is carried out using the etching solution according to any one of claims 1 to 7.