JP2021116449A - Etchant, replenishing solution and method for forming copper wiring - Google Patents

Abstract

To provide an etchant which is excellent in forming a fine pattern on a fine pitch pattern region in which a fine portion and a rough portion coexist, and to provide a replenishing solution thereof and a method for forming a copper wiring.SOLUTION: There is provided an etchant for copper, wherein the etchant comprises an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a 5-membered ring, an aliphatic heterocyclic compound (B) having a 5- to 7-membered ring, and a cationic polymer containing a tertiary or quaternary nitrogen in the molecule, and wherein the heteroaromatic compound (A) having a 5-membered ring is a hetero aromatic compound having one or more nitrogen atoms as a hetero atom constituting a ring, and the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is an aliphatic heterocyclic compound having one or more nitrogen atoms as a hetero atom constituting a ring.SELECTED DRAWING: None

Description

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

In the production of a printed wiring board, when a copper wiring pattern is formed by a photoetching method, an iron chloride-based etching solution, a copper chloride-based etching solution, an alkaline etching solution, or the like is used as the etching solution. When these etching solutions are used, copper under an etching resist called side etching may be melted from the side surface of the wiring pattern. That is, the portion that is originally desired not to be removed by etching (that is, the copper wiring portion) is removed by the etching solution by being covered with the etching resist, and the width becomes narrower from the bottom to the top of the copper wiring. The phenomenon of Such side etching should be reduced as much as possible, especially when the copper wiring pattern is fine. In order to suppress this side etching, an etching solution containing an azole compound which is a heteroaromatic compound having a 5-membered ring has been proposed (Patent Documents 1 to 4). Further, in order to suppress side etching, an etching solution containing an aliphatic heterocyclic compound having a 5- to 7-membered ring has also been proposed (Patent Document 5).

Japanese Unexamined Patent Publication No. 2005-330572 Japanese Unexamined Patent Publication No. 2009-221596 Japanese Unexamined Patent Publication No. 2013-104104 JP-A-2018-193602 Japanese Unexamined Patent Publication No. 2014-224303

On the other hand, in the market, there is a demand for an etching solution that has an effect of suppressing side etching and is excellent in forming a fine pattern of copper wiring. The etching solution disclosed in Patent Document as described above is expected to have a certain effect of suppressing side etching, but among these, the etching solution disclosed in Patent Document 4, which is judged to have high performance, has a line / space. A fine pattern can be formed with a pitch pattern in which a 20 μm pitch pattern region (fine portion) of 13 μm / 7 μm and a 40 μm pitch pattern region (rough portion) of line / space = 22 μm / 18 μm are mixed. Although it is specifically disclosed, the formation of a fine pattern in a finer (narrower) pitch pattern region has not been achieved.

The present invention has been made in view of the above circumstances, and provides an etching solution excellent in forming a fine pattern for a fine pitch pattern region in which a fine portion and a rough portion are mixed, a replenishing solution thereof, and a method for forming a copper wiring. The purpose is to do.

The present invention is a copper etching solution, wherein the etching solution contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a 5-membered ring, and an aliphatic complex having a 5- to 7-membered ring. The heterocyclic compound (B) and the heteroaromatic compound (A) containing a cationic polymer containing tertiary or quaternary nitrogen in the molecule and having the 5-membered ring are nitrogen as heteroatoms constituting the ring. The heteroaromatic compound having one or more atoms, and the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is an aliphatic heterocycle having one or more nitrogen atoms as a heteroatom constituting the ring. The present invention relates to an etching solution which is a formula compound.

The present invention is a replenisher to be added to the etchant when the etchant is used continuously or repeatedly, and the replenisher is a heteroaromatic compound (A) having a 5-membered ring and 5 to 7 of the replenisher. An aqueous solution containing an aliphatic heterocyclic compound (B) having a member ring and a cationic polymer containing tertiary or quaternary nitrogen in the molecule, and the heteroaromatic compound (A) having the 5-membered ring. Is a heteroaromatic compound having at least one nitrogen atom as a heteroatom constituting a ring, and the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is nitrogen as a heteroatom constituting the ring. The present invention relates to a supplement solution which is an aliphatic heterocyclic compound having one or more atoms.

The present invention relates to a method for forming a copper wiring that etches a portion of a copper layer that is not coated with an etching resist, and relates to a method for forming a copper wiring that is etched using the etching solution.

The etching solution of the present invention contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a 5-membered ring, an aliphatic heterocyclic compound (B) having a 5- to 7-membered ring, and the inside of the molecule. The heteroaromatic compound (A) containing a cationic polymer containing tertiary or quaternary nitrogen and having the 5-membered ring is a heteroaromatic compound having one or more nitrogen atoms as heteroatoms constituting the ring. The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is an aliphatic heterocyclic compound having one or more nitrogen atoms as heteroatoms constituting the ring. The etching solution of the present invention can form a fine pattern having excellent linearity in addition to suppressing side etching by forming a uniform film on a fine pitch pattern region in which a fine portion and a rough portion are mixed. .. Therefore, the etching solution of the present invention is useful for forming a copper wiring pattern on a copper surface provided with a resist.

Further, the etching solution of the present invention is excellent in forming a fine pattern and also in forming a rough pattern for a fine pitch pattern region in which a fine portion and a rough portion are mixed. When the liquid contains glycol ethers and / or glycols, it is particularly excellent in forming a rough pattern. Usually, since the flow velocity of the etching solution is different between the fine portion and the rough portion, there is a tendency that a difference is likely to occur between the film formation and the etching in the depth direction. For example, in a rough portion having a high flow velocity, it is difficult for the film to be formed to the bottom, so that a constriction (inverted trapezoidal shape) is likely to occur at the bottom portion of the rough pattern. When such a constriction of the bottom part occurs, it is difficult to manage the product because the bottom width cannot be observed from the upper part of the board, and when pressure is applied to the top part at the time of mounting, the corner of the top part is applied. , There is a risk of mounting defects and foreign matter. The etching solution of the present invention is useful because there is no difference in the etching properties of the fine portion and the rough portion (the shapes of the fine pattern and the rough pattern are substantially the same), and thus the above problem can be avoided. ..

<Copper etching solution>
The copper etching solution of the present invention comprises an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a 5-membered ring, and an aliphatic heterocyclic compound (B) having a 5- to 7-membered ring. The heteroaromatic compound (A) containing a cationic polymer containing tertiary or quaternary nitrogen in the molecule and having the 5-membered ring has a heteroaromatic compound having one or more nitrogen atoms as heteroatoms constituting the ring. The group compound, the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring, is an aliphatic heterocyclic compound having one or more nitrogen atoms as heteroatoms constituting the ring. The "copper" in the copper etching solution of the present invention may be made of copper or a copper alloy.

<Acid>
The acid of the present invention can be appropriately selected from an inorganic acid and an organic acid. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrobromic acid and the like. Examples of the organic acid include formic acid, acetic acid, oxalic acid, maleic acid, benzoic acid, glycolic acid and the like. Among the acids, hydrochloric acid is preferable from the viewpoint of etching rate stability and copper dissolution stability. At least one type of acid may be used, and two or more types may be used in combination.

The concentration of the acid is preferably 7 to 180 g / L, more preferably 18 to 110 g / L. When the acid concentration is 7 g / L or more, the etching rate is high, so that copper can be etched quickly. Further, when the acid concentration is 180 g / 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 may be any metal ion capable of oxidizing metallic copper, and examples thereof include ferric ion and ferric ion. From the viewpoint of suppressing side etching and the stability of the etching rate, it is preferable to use cupric ion as the oxidizing metal ion. At least one type of the oxidizing metal ion may be used, and two or more types may be used in combination.

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

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

<Complex aromatic compound (A) having a 5-membered ring>
The heteroaromatic compound (A) having a 5-membered ring of the present invention is a heteroaromatic compound having one or more nitrogen atoms as heteroatoms constituting the ring. As the heteroaromatic compound (A) having a 5-membered ring, at least one kind may be used, and two or more kinds may be used in combination.

The heteroaromatic compound (A) having a 5-membered ring preferably has only nitrogen as a heteroatom constituting the ring from the viewpoint of structural stability and solubility in an acidic liquid. Examples of the heteroaromatic compound (A) having such a 5-membered ring include azole compounds having an imidazole skeleton, pyrazole compounds having a pyrazole skeleton, triazole compounds having a triazole skeleton, and tetrazole compounds having a tetrazole skeleton. Examples include compounds.

Examples of the imidazole compound include imidazoles such as imidazole, 2-methylimidazole, 2-undecyl-4-methylimidazole, and 2-phenylimidazole, benzimidazole, 2-methylbenzoimidazole, 2-undecylbenzoimidazole, and 2 Examples thereof include benzimidazoles such as −phenylbenzoimidazole and 2-mercaptobenzimidazole. Of these, benzimidazole is preferred.

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. -Examples include 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, and benzotriazole. , 1-Methyl-benzotriazole, triltriazole and the like. Among these, 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, and 1-phenyl-5. Mercapto-1H-tetrazole, 1-cyclohexyl-5-mercapto-1H-tetrazole, 5,5'-bi-1H-tetrazole, and metal salts such as ammonium or Na salt, Zn salt, Ca salt, K salt and the like. And so on.

Among the azole compounds, the tetrazole compound is preferable from the viewpoint of having a high effect of suppressing undercut, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5 , 5'-bi-1H-tetrazole, and ammonium salts or metal salts thereof, etc. are more preferred, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-amino-1H-tetrazole, and ammonium salts or metals thereof. Salt is more preferred. It is presumed that these tetrazole compounds can form a thin and uniform protective film from the top portion to the side surface of the conductor pattern.

The concentration of the heteroaromatic compound (A) having a 5-membered ring is preferably 0.1 to 50 g / L, more preferably 0.1 to 15 g / L, and 0.2 to 10 g / L. It is more preferably L. When the concentration of the heteroaromatic compound (A) having a 5-membered ring is 0.1 g / L or more, side etching (particularly reduction in top width) can be reliably suppressed. On the other hand, when the concentration of the heteroaromatic compound (A) having a 5-membered ring is 50 g / L or less, it is possible to prevent a decrease in the etching rate and reliably etch the portion to be etched, so that a short circuit occurs. It is possible to prevent the occurrence of (insulation failure).

<Aliphatic heterocyclic compound (B) having a 5- to 7-membered ring>
The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring of the present invention is an aliphatic heterocyclic compound having one or more nitrogens as heteroatoms constituting the ring. At least one type of the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring may be used, and two or more types may be used in combination.

The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring has only nitrogen as a heteroatom constituting the ring in order to suppress side etching without lowering the linearity of the copper wiring. preferable. The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is preferably an aliphatic heterocyclic compound having 3 or less nitrogens constituting the ring from the viewpoint of stability in the etching solution. ..

Specific examples of the aliphatic heterocyclic compound include, for example, a pyrrolidine compound having a pyrrolidine skeleton, a piperazine compound having a piperazine skeleton, a piperazine compound having a piperazine skeleton, a homopiperazin compound having a homopiperazine skeleton, and hexahydro-1,3. , Hexahydro-1,3,5-triazine compound having a 5-triazine skeleton and the like can be exemplified. In the compounds listed above, the aliphatic heterocycle has 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 and a cyano group. , Imino group, phosphino group, thiol group, sulfo group and other substituents may be substituted.

（一般式（Ｉ）中、Ｒ^１〜Ｒ^５は、それぞれ独立に、水素、アミノ基含有置換基、又はアミノ基含有置換基を除く炭素数１〜１０の炭化水素誘導基を示す。これら置換基は互いに結合して環構造を形成していてもよい。） The pyrrolidine compound is not particularly limited as long as it is a compound having a pyrrolidine skeleton, and examples thereof include the pyrrolidine compound represented by the following formula (I).

(In the general formula (I), R ^{1 to} R ⁵ independently represent hydrogen, an amino group-containing substituent, or a hydrocarbon-inducing group having 1 to 10 carbon atoms excluding the amino group-containing substituent. The groups may be bonded to each other to form a ring structure.)

The amino group _{represents any of -NH 2} , -NHR, and -NRR', the R and R'independently represent hydrocarbon inducers having 1 to 10 carbon atoms, and R and R'are They may be bonded to each other to form a saturated ring structure. The amino group-containing substituent means either a substituent composed of an amino group or a substituent in which a part of hydrogen is replaced with an amino group by a hydrocarbon inducer having 1 to 10 carbon atoms. From the viewpoint of effectively suppressing side etching and further improving the linearity of copper wiring, a substituent composed of an amino group or an amino group-containing substituent composed of carbon, hydrogen and nitrogen is preferable. The same applies to the following amino groups and amino group-containing substituents.

The hydrocarbon-inducing group refers to a hydrocarbon group in which a part of carbon or hydrogen may be replaced with another atom or a substituent. Examples of the hydrocarbon inducing group include a methyl group, an ethyl group, a propyl group, a butyl group, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, an aryl group, an acetyl group, a phenyl group, a hydroxyethoxymethyl group, and a hydroxyethoxyethyl group. Group, hydroxyethoxypropyl group and the like can be exemplified, and from the viewpoint of effectively suppressing side etching and further improving the linearity of copper wiring, a hydrocarbon inducing group composed of carbon and hydrogen is preferable. The same applies to the following hydrocarbon inducers.

Specific examples of the pyrrolidine compound include pyrrolidine, 1- (2-hydroxyethyl) pyrrolidine, indolin, 1-isopyrrolidine-3-hydroxypyrrolidine, 1,2-cyclohexanedicarboxyimide, 1-butylpyrrolidine, 1-. Ethylpyrrolidine, 2- (2-hydroxyethyl) -1-methylpyrrolidine, 2-methylpyrrolidine, 1- (2-hydroxyethyl) pyrrolidine, 1- (3-aminopropyl) pyrrolidine, 1- (2-aminoethyl) Pyrrolidine, 3-aminopyrrolidine, 2-aminomethyl-1-ethylpyrrolidine, 2- (2-aminoethyl) -1-methylpyrrolidine, 3- (dimethylamino) pyrrolidine, 3- (methylamino) pyrrolidine, 1-( 2-Pyrrolidinylmethyl) pyrrolidine, 3- (diethylamino) pyrrolidine, 1,1'-dimethyl-3-aminopyrrolidine, 3- (ethylamino) pyrrolidine, 1-methyl-2- (1-piperidinomethyl) pyrrolidine, 4 -(1-Pyrrolidinyl) piperidine, 3- (N-acetyl-N-methylamino) pyrrolidine, 3- (N-acetyl-N-ethylamino) pyrrolidine, 2-pyrrolidincarboxamide, 3-pyrrolidincarboxamide, 3-acetamidopyrrolidine , 1-Ethyl-2-pyrrolidincarboxamide, 3-amino-1- (tert-butoxycarbonyl) pyrrolidine, 3- (tert-butoxycarbonylamino) pyrrolidine, 1-amino-2- (methoxymethyl) pyrrolidine, 1-benzyl -3-Aminopyrrolidine, 1-benzyl-3- (dimethylamino) pyrrolidine, 1-benzyl-3- (methylamino) pyrrolidine, 1-benzyl-3- (ethylamino) pyrrolidine, 3,4-diamino-1- Examples thereof include benzylpyrrolidine, 1-benzyl-3-acetamidopyrrolidine, (1s, 6s) -2,8-diazabicyclo [4.3.0] nonane and the like.

（一般式（ＩＩ）中、Ｒ^６〜Ｒ^１１は、それぞれ独立に水素、アミノ基含有置換基、又はアミノ基含有置換基を除く炭素数１〜１０の炭化水素誘導基を示す。これら置換基は互いに結合して環構造を形成していてもよい。） The piperidine compound is not particularly limited as long as it is a compound having a piperidine skeleton, and examples thereof include the piperidine compound represented by the following formula (II).

(In the general formula (II), R ^{6 to} R ¹¹ independently represent hydrogen, an amino group-containing substituent, or a hydrocarbon inducer having 1 to 10 carbon atoms excluding the amino group-containing substituent. May be combined with each other to form a ring structure.)

Specific examples of the piperidine compound include, for example, piperidin, 1-methylpiperidin, 2-methylpiperidin, 3-methylpiperidin, 4-methylpiperidin, 4-methylpiperidin, 3,5-dimethylpiperidin, 2-ethylpiperidin, and the like. 4-piperidincarboxylic acid, 1,2,3,4-tetrahydroquinolin, decahydroisoquinolin, 2,6-dimethylpiperidine, 2-piperidinmethanol, 3-piperidinmethanol, 4-piperidinmethanol, 2,2,6,6 -Tetramethyl Piperidine, 4-Amino Piperidine, 1-Amino Piperidine, 3-Amino Piperidine, 4- (Aminomethyl) Piperidine, 4-Amino-1-methyl Piperidine, 2- (Aminomethyl) Piperidine, 3- (Aminomethyl) ) Piperidine, 4-piperidin carboxamide, 2-piperidin carboxamide, 1- (2-aminoethyl) piperidine, 4-acetamide piperidine, 3-acetamide piperidine, 4-amino-1-isopropyl piperidine, 1- (3-aminopropyl) -2-Methylpiperidin, 4-amino-2,2,6,6-tetramethylpiperidine, 2,2'-bipiperidine, 4,4'-bipiperidine, 4-piperidinopiperidin, 4-amino-1-piperidin Examples thereof include ethyl carboxylate, 4-amino-1-benzyl piperidine, 4- (2-aminoethyl) -1-benzyl piperidine, 4-acetamide-1-bencil piperidine and the like.

（一般式（ＩＩＩ）中、Ｒ^１２〜Ｒ^１７は、それぞれ独立に水素、アミノ基含有置換基、又はアミノ基含有置換基を除く炭素数１〜１０の炭化水素誘導基を示す。これら置換基は互いに結合して環構造を形成していてもよい。） The piperazine compound is not particularly limited as long as it is a compound having a piperazine skeleton, and examples thereof include the piperazine compound represented by the following formula (III).

(In the general formula (III), R ^{12 to} R ¹⁷ independently represent hydrogen, an amino group-containing substituent, or a hydrocarbon inducer having 1 to 10 carbon atoms excluding the amino group-containing substituent. May be combined with each other to form a ring structure.)

Specific examples of the piperazine compound include, for example, piperazine, 1-methylpiperazine, 2-methylpiperazine, 1-allyl piperazine, 1-isobutyl piperazine, 1-hydroxyethoxyethyl piperazine, 1-phenylpiperazine, 1-aminopiperazine, and the like. 1-Aminoethylpiperazine, N- (2-aminoethylpiperazine), 1-amino-4-methylpiperazine, 1-ethylpiperazine, 1-piperazine ethanol, ethyl 1-piperazine carboxylate, 1-formylpiperazine, 1-propyl Piperazine, 1-Acetyl Piperazine, 1-Isopropyl Piperazine, 1-Cyclopentyl Piperazine, 1-Cyclohexyl Piperazine, 1- (2-methoxyethyl) Piperazine, 1-Piperonyl Piperazine, 1- (Diphenylmethyl) Piperazine, 2-Piperazineone , 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-piperazindione, 1-methyl-4- (1,4'-bipiperidin-4-yl) piperazine, 1- (4-aminophenyl) -4- (4) -Methenylphenyl) piperazine, 1,4-dimethylpiperazine-2-one, 1,4-diethylpiperazine-2-one, 1,4-dimethylpiperazine-2,3-dione, 2-piperazinecarboxylic acid, triethylenediamine, etc. Can be mentioned.

（一般式（ＩＶ）中、Ｒ^１８〜Ｒ^２４は、それぞれ独立に水素、アミノ基含有置換基、又はアミノ基含有置換基を除く炭素数１〜１０の炭化水素誘導基を示す。これら置換基は互いに結合して環構造を形成していてもよい。） The homopiperazine compound is not particularly limited as long as it is a compound having a homopiperazine skeleton, and examples thereof include the homopiperazine compound represented by the following formula (IV).

(In the general formula (IV), R ^{18 to} R ²⁴ independently represent hydrogen, an amino group-containing substituent, or a hydrocarbon inducer having 1 to 10 carbon atoms excluding the amino group-containing substituent. May be combined with each other to form a ring structure.)

Specific examples of the homopiperazine compound include, for example, homopiperazine, 1-methylhomopiperazine, 1-formylhomopiperazine, 1,4-dimethylhomopiperazin, 4-methyl-1-homopiperazine dithiocarboxylic acid, 1-acetyl. Examples thereof include homopiperazine and 1-butyryl homopiperazine.

（一般式（Ｖ）中、Ｒ^２５〜Ｒ^３０は、それぞれ独立に水素、アミノ基含有置換基、又はアミノ基含有置換基を除く炭素数１〜１０の炭化水素誘導基を示す。これら置換基は互いに結合して環構造を形成していてもよい。） The hexahydro-1,3,5-triazine compound is not particularly limited as long as it is a compound having a hexahydro-1,3,5-triazine skeleton, and is, for example, hexahydro-1,3,5 represented by the following formula (V). -Triazine compounds can be exemplified.

(In the general formula (V), R ^{25 to} R ³⁰ independently represent hydrogen, an amino group-containing substituent, or a hydrocarbon inducer having 1 to 10 carbon atoms excluding the amino group-containing substituent. May be combined with 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, and 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-1,3,5-Trinitroso-1,3,5-Triazine, Hexahydro-2,4,6-trimethyl-1,3,5-Trinitro-1,3,5-Triazine, Hexahydro- Examples thereof include 1,3,5-triacryloyl-1,3,5-triazine and hexamethylenetetramine.

The concentration of the aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is 0.01 to 10 g from the viewpoint of improving the formation of a fine pattern in a fine pitch pattern region in which a fine portion and a rough portion are mixed. It is preferably / L, more preferably 0.02 to 5 g / L, and even more preferably 0.05 to 3 g / L.

<Cationic polymer containing tertiary or quaternary nitrogen>
As the cationic polymer containing tertiary or quaternary nitrogen of the present invention, known ones can be used, for example, a dicyandiamide / polyalkylene polyamine polycondensate such as a dicyandiamide / diethylenetriamine polycondensate, or a dicyandiamide / formaldehyde polycondensate. , Dicianamide-based cationic polymers such as dicyandiamide / triethylenetetramine polycondensate; polyallylamine, allylamine / dimethylallylamine copolymer, diallyldimethylammonium chloride polycondensate, diallylamine acetate / sulfur dioxide copolymer, diallylmethylethylammonium Polyallylamine-based such as ethylsulfate / sulfur dioxide copolymer, polyallylamineamide sulfate, allylamine acetate / diallylamine acetate copolymer, methyldiallylamineamide sulfate polymer, diallylamineamide sulfate / maleic acid copolymer, etc. Cationic polymers; polycondensates of aliphatic monoamines such as dimethylamine / epichlorohydrin polycondensate and epihalohydrin compounds can be mentioned. Among these, from the viewpoint of being able to form a copper wiring having excellent linearity, the cationic polymer containing tertiary or quaternary nitrogen is a dicyandiamide / polyalkylene polyamine polycondensate such as a dicyandiamide / diethylenetriamine polycondensate. A dicyandiamide / formaldehyde polycondensate, a cyandiamide / triethylenetetramine polycondensate, and a diallyldimethylammonium chloride polycondensate are preferable. At least one type of the cationic polymer containing tertiary or quaternary nitrogen may be used, and two or more types may be used in combination.

The concentration of the cationic polymer containing tertiary or quaternary nitrogen is 0.001 to 10 g / L from the viewpoint of improving the formation of a fine pattern in a fine pitch pattern region in which a fine portion and a rough portion are mixed. It is preferably 0.005 to 5 g / L, more preferably 0.01 to 2 g / L.

<Glycol ethers and / or glycols>
The etching solution of the present invention contains glycol ethers and / or glycols from the viewpoint of excellent fine pattern formation and rough pattern formation for a fine pitch pattern region in which a fine portion and a rough portion are mixed. Is preferably included. The glycol ethers and / or glycols may be used in combination of two or more.

Known glycol ethers can be used, for example, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and the like. 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, di Examples thereof include propylene glycol dimethyl ether. Among these, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and dipropylene glycol monomethyl ether are preferable.

Known glycols can be used, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, methylpropylene glycol, dimethyldiglycol, methylethyldiglycol, methyldipropylene glycol, methylpropylene triglycol, and the like. Examples thereof include polyethylene glycol and polypropylene glycol. Among these, diethylene glycol, methylpropylene glycol, methyldipropylene glycol, and methylethyldiglycol are preferable.

The concentration of the glycol ethers and / or glycols shall be 0.01 to 30 g / L from the viewpoint of improving the formation of the fine pattern and the rough pattern in the fine pitch pattern region in which the fine portion and the rough portion are mixed. , More preferably 0.1 to 10 g / L, and even more preferably 0.1 to 5 g / L.

In addition to the above-mentioned 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. Examples of the other components include aliphatic acyclic compounds such as diethylenetriamine, triethylenetetramine, tetraethylpentamine, and pentaethylenehexamine; and component stabilizers such as cationic surfactants, anionic surfactants, and amphoteric surfactants. May be added. When the other components are added, the concentration thereof is usually about 0.001 to 5 g / L.

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

The etching solution may be blended so that each component has a predetermined concentration at the time of use, or a concentrated solution may be prepared and diluted immediately before use. The method of using the etching solution is not particularly limited, but in order to effectively suppress side etching, it is preferable to perform etching using a spray as described later. The temperature of the etching solution during use is not particularly limited, but it is preferably used at 20 to 55 ° C. in order to effectively suppress side etching while maintaining high productivity.

The replenisher of the present invention is a replenisher to be added to the etching solution when the etching solution of the present invention is used continuously or repeatedly, and the heteroaromatic compound (A) having the 5-membered ring and the above 5 It is an aqueous solution containing an aliphatic heterocyclic compound (B) having a ~ 7-membered ring and a cationic polymer containing tertiary or quaternary nitrogen in the molecule. Each component in the supplement solution is the same as the component that can be blended in the etching solution of the present invention described above. By adding the supplementary solution, the ratio of each component of the etching solution is maintained appropriately, so that the effect of the etching solution of the present invention described above can be stably maintained.

Further, the supplementary solution of the present invention may contain an acid such as hydrochloric acid. Further, the supplementary solution may contain oxidizing metal ions such as cupric chloride. In addition to the above components, the supplement solution may contain other components to be added to the etching solution. It should be noted that these components that may be contained in the supplementary solution should be added directly to the etching solution of the present invention when the etching solution of the present invention is used continuously or repeatedly without being contained in the supplementary solution. You can also do it.

The method for forming a copper wiring of the present invention is a method for forming a copper wiring for etching a portion of a copper layer not covered with an etching resist, characterized in that etching is performed using the etching solution of the present invention described above. As a result, as described above, an excellent fine pattern of copper wiring can be formed in a fine pitch pattern region in which a fine portion and a rough portion are mixed. Further, in the copper wiring forming step adopting 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 etching while adding the replenishing solution of the present invention described above. This is because the ratio of each component of the etching solution is maintained appropriately, so that the effect of the etching solution of the present invention described above can be stably maintained.

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

When etching by spray, the spray pressure is preferably 0.04 MPa or more, more preferably 0.08 MPa or more. When the spray 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, side etching can be effectively prevented. The spray pressure is preferably 0.40 MPa or less from the viewpoint of preventing damage to the etching resist.

Next, examples of the present invention will be described together with comparative examples. The present invention is not construed as being limited to the following examples.

Each etching solution having the composition shown in Tables 1 and 2 was prepared, etched under the conditions described later, and each item was evaluated by the evaluation method described later. In each etching solution having the composition shown in Tables 1 and 2, the balance is ion-exchanged water. The concentration of hydrochloric acid shown in Tables 1 and 2 is the concentration of hydrogen chloride.

(Test board used)
A copper / polyimide laminated plate (manufactured by Toray Film Co., Ltd., trade name "PI-38N-CCS-08EO") with a copper layer thickness of 8 μm was prepared, and a photolithography method (resist agent (manufactured by Tokyo Ohka) was applied on the copper layer. An etching resist pattern was formed by PMER-P-RZ30 ")). The etching resist pattern is a resist pattern in which an 18 μm pitch pattern region (fine portion) having a thickness of about 4 μm and a line / space = 11 μm / 7 μm and a 25 μm pitch pattern region (rough portion) having a line / space = 16 μm / 9 μm are mixed. Was produced.

(Etching conditions)
Etching was performed using a fan-shaped nozzle (manufactured by Ikeuchi Co., Ltd., trade name "ISVV9020") under the conditions of a spray pressure of 0.20 MPa and a treatment temperature of 35 ° C. The processing time was set to the time during which the bottom width of the copper wiring became 8 to 15 μm at a pitch of 18 μm. After etching, it was washed with water and dried to perform the evaluation shown below.

(Evaluation of fine pattern)
Each etched test substrate was sprayed with hydrochloric acid (hydrogen chloride concentration: 7% by weight) using a fan-shaped nozzle (manufactured by Ikeuchi, trade name: ISVV9020) at a spray pressure of 0.15 MPa and a protective film was removed in a treatment time of 40 seconds. Then, it was immersed in acetone for 20 seconds (or 3 wt% aqueous sodium hydroxide solution for 60 seconds) to remove the etching resist. Then, a part of each test substrate was cut, embedded in a cold-embedded resin, and polished so that the cross section of the wiring could be observed to prepare a sample for cross-section observation. To observe the cross section of the wiring, an image was taken using an optical microscope, and the top width and bottom width of the wiring were measured. At this time, the measurement was performed with n = 2 or more, and the top width and the bottom width were taken as the average value. In addition, BT in the table is the value of the bottom width-top width of the copper wiring. In the column of the fine part in the table, the case where the value of BT in the 18 μm pitch pattern region of line / space = 11 μm / 7 μm was 0 ≦ BT ≦ 2 μm was marked with ◯, and the other cases were marked with ×. For the linearity of the fine part, the bottom width was measured at 50 points, their standard deviations were calculated, and when it was 0.50 or less, it was judged as 〇 (passing standard for linearity), and in other cases, it was judged as x. Further, in the rough portion column, when the value of BT in the 25 μm pitch pattern region of line / space = 19 μm / 9 μm is 0 or more, it is preferable from the viewpoint that constriction at the bottom portion of the rough pattern is unlikely to occur. Further, the numerical value obtained by subtracting the BT of the rough portion from the BT of the fine portion is defined as the sparse / dense difference, and it can be judged that the closer this numerical value is to 0, the more the etching property of the fine portion and the rough portion is not different. preferable.

Claims (8)

It is a copper etching solution
The etching solution contains an acid, an oxidizing metal ion, a heteroaromatic compound (A) having a 5-membered ring, and an aliphatic heterocyclic compound (B) having a 5- to 7-membered ring. Contains cationic polymers containing tertiary or quaternary nitrogen,
The heteroaromatic compound (A) having a 5-membered ring is a heteroaromatic compound having one or more nitrogen atoms as heteroatoms constituting the ring.
The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is an etching solution characterized by being an aliphatic heterocyclic compound having one or more nitrogen atoms as heteroatoms constituting the ring. 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 cupric ion. Claims 1 to 3 characterized in that the heteroaromatic compound (A) having a 5-membered ring is one or more compounds selected from the group consisting of an imidazole compound, a pyrazole compound, a triazole compound, and a tetrazole compound. The etching solution according to any one of. The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is selected from the group consisting of a pyrrolidine compound, a piperazine compound, a piperazine compound, a homopiperazin compound, and a hexahydro-1,3,5-triazine compound1 The etching solution according to any one of claims 1 to 4, which is a compound of more than one species. The etching solution according to any one of claims 1 to 5, which comprises glycol ethers and / or glycols. A supplementary solution to be added to the etching solution when the etching solution according to any one of claims 1 to 6 is used continuously or repeatedly.
The replenisher contains a heteroaromatic compound (A) having a 5-membered ring, an aliphatic heterocyclic compound (B) having a 5- to 7-membered ring, and tertiary or quaternary nitrogen in the molecule. An aqueous solution containing a cationic polymer
The heteroaromatic compound (A) having a 5-membered ring is a heteroaromatic compound having one or more nitrogen atoms as heteroatoms constituting the ring.
The aliphatic heterocyclic compound (B) having a 5- to 7-membered ring is a supplement solution characterized by being an aliphatic heterocyclic compound having one or more nitrogen atoms as heteroatoms constituting the ring. A method for forming copper wiring that etches a portion of a copper layer that is not covered with an etching resist.
A method for forming copper wiring, which comprises etching with the etching solution according to any one of claims 1 to 7.