TWI422711B - Etching solution and conductor pattern formation method - Google Patents

Description

Method for forming etching liquid and conductor pattern

The present invention relates to an etching solution for copper and a method of forming a conductor pattern using the same.

In the production of a printed circuit board, when a conductor pattern (a wiring pattern, a terminal pattern, or the like) made of copper is formed by photolithography, a ferric chloride-based etching solution, a copper chloride-based etching solution, an alkaline etching solution, or the like is used. As an etchant. However, in these etching liquids, there is a problem that copper under the etching resistance called undercut starts to dissolve from the side. That is, a phenomenon occurs in which a portion (i.e., a wiring portion) which is not originally removed by etching by a resist is desired to be removed by side etching, and is widened and narrowed from the bottom to the top of the wiring. Phenomenon (undercut). In particular, when the wiring pattern is fine, such undercut must be as small as possible.

In the past, an etching liquid capable of suppressing the above undercut has been studied. For example, Patent Document 1 listed below proposes an aqueous solution containing an aqueous solution of a copper chloride, a hydrochloric acid, a 2-aminobenzothiazole compound, a polyethylene glycol, and a specific alkylene polyamine compound.

Further, Patent Document 2 listed below discloses an etching liquid for pattern formation which is provided with a small amount of undercut by blending a specific azole, and can prevent the top of the copper wiring from being thinned.

Patent Document 1: Japanese Patent Laid-Open No. Hei 6-57453, Patent Document 2: Japanese Patent Laid-Open Publication No. 2005-330572

However, in the conventional etching liquid described in the above-mentioned Patent Document 1, the undercut is not sufficiently suppressed, and an etching liquid capable of further suppressing undercut is required.

Further, the etching liquid described in Patent Document 2 has the following problems.

If copper ions are used as the oxidizing agent for the etching liquid, copper ions react with the etched metal copper during the etching to form cuprous ions, and the concentration of the cuprous ions increases. When the concentration of cuprous ions exceeds 5 g/L, the etching performance is lowered. Therefore, an oxidizing agent such as hydrogen peroxide is usually added to the etching liquid to carry out a reaction of regenerating cuprous ions into copper ions.

However, when hydrogen peroxide is added, the azole contained in the etching solution is also decomposed, and the top of the wiring pattern becomes fine.

In order to prevent this, it is necessary to perform etching while managing the azole concentration to a certain level or more, and the management is rather complicated.

An object of the present invention is to provide an etching solution and a method for forming a conductor pattern using the same, which is an oxidizing agent such as hydrogen peroxide to regenerate cuprous ions into copper ions when the etching performance is lowered, and can be repeated for a long period of time. Or a continuous user; wherein the top shape of the pattern can be etched into a desired shape in a state where the undercut is small, and even if it is continuously used, the azole concentration can be easily maintained at a certain level or more, and the top shape of the pattern can be maintained while maintaining Etching is performed.

The etching liquid of the present invention contains a copper ion source, an acid and a copper etching solution for water; and the alloy contains an azole and an aromatic compound, and the azole has only a nitrogen atom as a hetero atom existing in the ring, and the aromatic The compound is selected from at least one of a phenol and an aromatic amine.

The "copper" in the above invention may be made of pure copper or may be made of a copper alloy. In addition, in the present specification, "copper" means pure copper or a copper alloy.

In the method for forming a conductor pattern according to the present invention, the portion of the copper layer on the electrically insulating material that is not covered with the resist is etched using the etching solution of the present invention to form a conductor pattern.

In the etching liquid of the present invention and the method for forming a conductor pattern using the same, the pattern top shape can be etched into a desired shape in a state where side etching is small, and the azole concentration can be easily obtained even if the etching liquid is continuously or repeatedly used. It is maintained at a certain level or more and can be etched while maintaining the top shape of the pattern.

The present invention is directed to a copper etching solution of the type in which a copper etching liquid is used to generate cuprous ions during etching and the etching performance is lowered, and a cuprous ion is regenerated into copper ions by adding an oxidizing agent such as hydrogen peroxide. , the type of repeated or continuous use. The components and the like constituting the etching liquid will be described in detail below.

(copper ion source)

The copper ion source is a component added as an oxidizing agent for oxidizing metallic copper. The type of the copper ion source may, for example, be copper chloride, copper sulfate, copper bromide, a copper salt of an organic acid, or copper hydroxide. Among them, copper chloride is particularly preferred because of its high solubility and fast etching rate.

Further, the concentration range of the copper ion source is preferably in the range of 14 to 155 g/L, and particularly preferably in the range of 33 to 122 g/L. As long as it is Within the range, the etching rate can be prevented from decreasing, and the etching rate can be stably maintained due to the good solubility of copper ions. When a preferred copper ion source, copper chloride, is used, the concentration of copper chloride is preferably in the range of 30 to 330 g/L, more preferably 70 to 260 g/L.

(acid)

The acid is a component added to dissolve copper metal oxidized by copper ions. The type of the acid to be used may be at least one selected from the group consisting of inorganic acids and organic acids.

Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and the like. Examples of the organic acid include formic acid, acetic acid, oxalic acid, maleic acid, benzoic acid, and glycolic acid. Among them, hydrochloric acid is preferred from the viewpoint of stability of etching rate and dissolution stability of copper (when copper cuppide and copper ions are held in an etching solution).

The concentration of the acid is preferably from 7 to 180 g/L, more preferably from 18 to 110 g/L, still more preferably from 18 to 80 g/L. As long as the acid concentration is 7 g/L or more, a stable etching rate can be obtained, and a decrease in the dissolution stability of copper can be prevented. On the other hand, as long as the acid concentration is 180 g/L or less, it is possible to prevent the etching liquid from eroding between the corrosion inhibitor and the copper, and to prevent re-oxidation of the copper surface.

(Azole having only a nitrogen atom as a hetero atom present in the ring)

In order to suppress the undercut, an azole having only a nitrogen atom as a hetero atom existing in the ring (hereinafter, also simply referred to as "oxazole") is added to the etching solution of the present invention.

The mechanism by which azole inhibits undercutting is not clear. We believe that the reason is as follows: by the copper ion junction in the liquid near the top of the conductor pattern and near the side In combination, a protective film is formed on the side from the top of the conductor pattern, thereby suppressing undercut.

The type of the azole to be used may be a monocyclic compound or a compound obtained by condensation of a ring. The imidazole compound, the triazole compound, and the tetrazole compound are particularly preferable, and two or more of these azoles may be used in combination.

Examples of the above imidazole compound include imidazoles such as imidazole, 2-methylimidazole, 2-undecyl-4-methylimidazole, and 2-phenylimidazole, benzimidazole, and 2-methylbenzone. Benzimidazoles such as imidazole, 2-undecylbenzimidazole, 2-phenylbenzimidazole, 2-mercaptobenzimidazole, and the like.

Examples of the above 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, tolyltriazole, and the like.

Examples of the above tetrazole compound may, for example, be 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-nonyl group- 1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 1-cyclohexyl-5-mercapto-1H-tetrazole, 5,5'-bis-1H-tetrazole, and ammonium salts thereof a salt or a metal salt such as a Na salt, a Zn salt, a Ca salt or a K salt.

Among the exemplified azoles described above, tetrazole compounds are particularly preferred. This is because the performance of not only suppressing the undercut is high, but also the pattern can be clearly formed.

Further, among the tetrazole compounds, 1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5,5'-bis-1H-tetrazole, and The ammonium salt or metal salt or the like is particularly preferably 1H-tetrazole, 5-amino-1H-tetrazole, and the like, or an ammonium salt or a metal salt thereof. It is assumed that these tetrazole compounds can form a protective film thinly and uniformly on the side from the top of the conductor pattern.

Further, 5-amino-1H-tetrazole, and an ammonium salt or a metal salt thereof, are particularly easily decomposed by hydrogen peroxide, and in the case where excess cuprous ions are regenerated into copper ions, in the presence of excess hydrogen peroxide, The concentration changes with time tends to become larger. Therefore, the effect of maintaining the concentration obtained by adding an aromatic compound described later is remarkable as compared with the case where it is not added, and thus it is suitable for the present invention.

The concentration of the azole is preferably 0.1 to 50 g/L, more preferably 0.1 to 15 g/L, still more preferably 0.2 to 10 g/L. As long as the concentration of the azole is 0.1 g/L or more, the undercut can be suppressed exactly. On the other hand, when the concentration of the azole is 50 g/L or less, the decrease in the etching rate can be prevented, and the portion to be etched can be surely etched, so that occurrence of a short circuit (insulation failure) can be prevented.

(an aromatic compound selected from at least one of a phenol and an aromatic amine)

In order to prevent decomposition of the azole by an oxidizing agent such as hydrogen peroxide, an aromatic compound selected from at least one of a phenol and an aromatic amine is added to the etching solution of the present invention (hereinafter, also simply referred to as "aromatic compound" "). The above "aromatic compound" does not include azole.

The mechanism by which the aromatic compound inhibits the decomposition of the azole by the oxidizing agent is not clear, but the reason is considered as follows: The aromatic compound has a shape which is formed when an oxidizing agent such as hydrogen peroxide is added and is called a hydroxyl radical. The role of substances that strongly oxidize. Although the azole is decomposed by the hydroxyl radical, the hydroxyl radical is trapped by the aromatic compound by adding the aromatic compound in advance, and therefore, even if an oxidizing agent is added, decomposition of the azole by the hydroxyl radical can be suppressed.

Among the above aromatic compounds, in particular, phenols are preferred because they have an excellent effect of inhibiting the decomposition of azole. Hereinafter, an aromatic compound is specifically exemplified.

Specific examples of the phenols include 2,4,6-tris(dimethylaminomethyl)phenol (mono), phenolsulfonic acid or a salt thereof (monobasic), cresolsulfonic acid or a salt thereof (monobasic), Salicylic acid or its salt (mono), lignosulfonic acid or its salt (mono), phenol (mono), catechol (binary, hydroxy asymmetric), xylenol (mono), gallic acid (three , phenylphenol (mono), pyrogallol (ternary), pyrogallol (ternary), hydroquinone (binary, hydroxy symmetric), 2,6-di-t-butyl - p-cresol (mono), 2,6-di-tert-butyl-4-ethylphenol (mono), 3-tert-butyl-4-hydroxyanisole (mono), and the like. In the above, the number of elements corresponds to the number of hydroxyl groups.

Among these phenols, a one-component substance is particularly effective compared with a substance of two or more. Further, in the case of a binary (in the case of a phenol having two hydroxyl groups), a phenol having a hydroxyl group asymmetrically with respect to the center of the aromatic ring tends to have a higher effect than a phenol having a hydroxyl group symmetrically. Further, dissolved in water The effect of high phenol is higher.

Among the above phenols, the effect of inhibiting the decomposition of the azole by the oxidizing agent is high, and particularly preferred is phenolsulfonic acid or a salt thereof, cresolsulfonic acid or a salt thereof, salicylic acid or a salt thereof, lignosulfonic acid or Its salt, 2,4,6-tris(dimethylaminomethyl)phenol and the like.

Specific examples of the aromatic amines include naphthalene diamine, aniline, naphthylamine, methylaniline, dimethylaniline, phenylethylamine, benzylamine, dibenzylamine, phenylenediamine, and trichloroaniline. Toluene diamine, diphenylamine, triphenylamine, o-nitro-p-chloroaniline, toluidine, and the like.

Among these aromatic amines, the effect of inhibiting the decomposition of the azole by the oxidizing agent is high, and particularly preferred are naphthalene diamine, aniline, naphthylamine and the like.

The concentration of the above aromatic compound is preferably 0.01 to 20 g/L, more preferably It is 0.1~10g/L. As long as it is within this range, the decomposition of the azole can be surely prevented, and the decrease in the etching rate can be prevented.

(hydrogen peroxide)

When the etching of copper is performed by the etching liquid of the present invention, the cuprous ions generated by the change of copper ions and metallic copper in the etching liquid increase during the etching. Therefore, hydrogen peroxide can be added as an oxidizing agent for oxidizing the cuprous ions to be regenerated into copper ions.

Hydrogen peroxide may be added to the etching solution in advance, or may be added in the middle of etching. Alternatively, an etching solution to which hydrogen peroxide is added in advance may be used, and hydrogen peroxide may be further added in the middle of etching. Usually, hydrogen peroxide is often added in the middle of etching.

The preferred addition amount of hydrogen peroxide varies depending on the amount of cuprous ions generated, and thus cannot be specified numerically. For example, if the concentration in the etching solution ranges from 0.01 to 20 g/L, It is easy to regenerate the produced cuprous ions into copper ions. The amount of the hydrogen peroxide to be added may be changed in accordance with the amount of the cuprous ion, for example, the ratio of the amount of the etching liquid to the amount of the object to be etched, and the etching time, etc., as long as it is the present invention. The general knowledge in the art can be appropriately adjusted. Of course, it is possible to add hydrogen peroxide when the cuprous ion concentration is increased while measuring the change in the cuprous ion concentration, or it is possible to measure in advance how the cuprous ion concentration changes as the etching progresses. The benchmark is to add hydrogen peroxide.

Although the cuprous ion does not function as an oxidizing agent for copper etching, it has a function of assisting the azole to inhibit the undercut by the presence of a small amount.

The concentration of cuprous ions is preferably in the range of 5 g/L or less, more preferably 2.5 g/L or less, still more preferably 2.0 g/L or less, still more preferably 0.7 g/L or less. As long as the cuprous ion concentration is 5 g/L or less, the etching rate can be prevented from being lowered, and the portion to be etched can be surely etched, so that occurrence of a short circuit (poor insulation) can be prevented. The lower limit of the concentration of cuprous ions is not particularly limited, and as described above, there is a function of assisting the action of the azole to inhibit undercut by the presence of a small amount.

The amount of hydrogen peroxide added for maintaining the cuprous ion concentration in the above range can be appropriately adjusted as described above. For example, in order to regenerate 10 g of cuprous ions into copper ions, 2.7 g of hydrogen peroxide is required, and thus Hydrogen peroxide is added to the concentration of cuprous ions produced. However, if the amount of hydrogen peroxide in the etching solution is excessive, chlorine gas or heat generation is generated, which is dangerous. Therefore, it is preferable to add the cuprous ion concentration within the above range.

The method for managing the etching liquid for maintaining the cuprous ion concentration in the above range may directly measure the concentration of cuprous ions, or may measure the oxidation-reduction potential of the etching solution and convert it into a concentration of cuprous ions.

(other additives)

In order to improve the stability of the liquid, uniform etching is performed to make the surface shape after etching uniform, and may be selected from cationic surfactants, glycols and glycol ethers in the etching solution of the present invention as needed. At least one of various additives such as an alcohol, a guanamine, an anionic surfactant, a solvent, a nonionic surfactant, an amphoteric surfactant, and a cationic polymer. Specific examples of these additives are as follows.

Cationic surfactant: alkyl type quaternary ammonium salt such as benzalkonium chloride or alkyltrimethylammonium chloride.

Diol: ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol (the number of carbon atoms of the alkylene group is about 4 to 500).

Glycol ether: propylene glycol monoethyl ether, ethylene glycol monobutyl ether, 3-methyl-3-methoxybutanol, dipropylene glycol methyl ether, diethylene glycol butyl ether, and the like.

Alcohols: methanol, ethanol, 1-propanol, 2-propanol, butanol, benzyl alcohol, 2-phenoxyethanol, and the like.

Amidoxime: N,N-dimethylformamide, Dimethy imidazolidinone, N-methylpyrrolidone, and the like.

Anionic surfactants: fatty acid salts, alkyl sulfate salts, alkyl phosphate salts, and the like.

Solvent: an anthraquinone such as dimethyl hydrazine.

Nonionic surfactants: polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, block polymers of polyoxyethylene and polyoxypropylene, and the like.

Amphoteric surfactants: lauryl dimethylaminoacetate betaine, octadecyldimethylammonium acetate betaine, lauryl hydroxy sulfobetaine and other betaine, lauryl dimethylamine oxide, amino carboxylic acid Acid, etc.

Further, the cationic polymer is preferably a substance which exhibits a cationic behavior in water and has a molecular weight of 1,000 or more, and more preferably a polymer compound having a molecular weight of several thousands to several millions. Specific examples thereof include polyethyleneimine, polyalkylene polyamine, quaternary ammonium salt type styrene polymer, and quaternary ammonium salt type aminoalkyl (meth) acrylate polymer. , a quaternary ammonium salt type diallylamine polymer, a quaternary ammonium salt type diallylamine and an acrylonitrile A copolymer of an amine, a polymer of a salt of an aminoalkyl acrylamide, a cationic cellulose derivative, or the like. The above salt may, for example, be a hydrochloride. Among the cationic polymers, polyethyleneimine or polyalkylenepolyamine is preferred. These cationic polymers may be used in combination of two or more kinds. Further, as the cationic polymer, commercially available ones such as a resin, an antistatic agent for fibers, a polymer aggregating agent for wastewater treatment, and a conditioner for hair rinsing can be used.

The etching solution of the present invention can be easily prepared by dissolving the above components in water. The water is preferably water such as ion-exchanged water, pure water or ultrapure water which removes ionic substances and impurities.

When the etching liquid of the present invention is repeatedly used, a replenishing liquid can be used in order to perform concentration management on each component.

In the case of the replenishing liquid, each component in the etching liquid can be maintained by using a replenishing liquid containing the following components.

a) an acid b) an azole having only a nitrogen atom as a hetero atom present in the ring c) an aromatic compound selected from at least one of a phenol and an aromatic amine

It is preferable to use the same kind of substance as the etching liquid for these various components.

The replenishing liquid is preferably a replenishing liquid containing a concentration range in which the a component is in a concentration range of 7 to 360 g/L, a b component is in a concentration range of 0.1 to 50 g/L, and a c component is in a concentration range of 0.01 to 20 g/L.

By adding the replenishing liquid, the respective component ratios of the etching liquid are appropriately maintained, so that a conductor pattern having few undercuts can be stably formed.

In the acid, from the viewpoint of solubility stability of copper, salt is preferred. acid. In the replenishing liquid, copper chloride may be further contained in a concentration range in which the copper ion concentration does not exceed 14 g/L. Further, the above additives may also be contained.

In general, when hydrogen peroxide is added as described above, the azole is decomposed by hydrogen peroxide and the concentration is drastically lowered. In the present invention, since the aromatic compound is added, the reduction of the azole caused by hydrogen peroxide can be suppressed.

Therefore, even when the respective concentrations are adjusted by using the above-mentioned replenishing liquid, the concentration management of each component can be performed without considering the reduction by the oxidizing agent such as hydrogen peroxide, and the concentration management of the etching liquid can be easily performed. In addition, the etching is performed while maintaining the azole concentration at 0.1 to 50 g/L, and as described above, not only the undercut can be surely suppressed, but also the etching rate can be prevented from being lowered.

When the wiring pattern is formed using the etching liquid of the present invention, it is possible to obtain a copper wiring having a small undercut (including a copper alloy wiring, the same applies hereinafter). Specifically, for example, a copper wiring having an Etching factor of more than 5 can be stably formed. In addition, it is easy to manage the concentration of the etching liquid at the time of etching.

The term "etching factor" as used herein means that the thickness (height) of the copper wiring is T, the width of the top of the copper wiring is W ₁ , and the width of the bottom of the copper wiring is W ₂ , and 2T/( W ₂ -W ₁ ) The calculated value (see Fig. 1). Fig. 1 is a schematic cross-sectional view showing an example of a wiring pattern obtained by using the etching liquid of the present invention. Reference numeral 1 is a so-called glass epoxy substrate impregnated with an epoxy resin in a glass fiber fabric, a so-called phenol resin paper substrate impregnated with phenol resin in paper, and impregnated with an aromatic polyamide fiber nonwoven fabric. A substrate (electrical insulating material) of an epoxy resin such as an aromatic polyamine epoxy substrate, a polyimide film, or a ceramic substrate. Reference symbol 2 is a copper wiring. Reference numeral 3 is a corrosion inhibitor resin (corrosion inhibitor). Further, W ₁ represents the width of the top of the copper wiring, and W ₂ represents the width of the bottom of the copper wiring. If the copper wiring is formed by the etching liquid of the present invention, the difference W ₂ -W ₁ between the width W ₂ at the bottom of the copper wiring and the width W ₁ of the copper wiring top can be reduced, and the above etching factor can be increased. .

[Examples]

Hereinafter, the present invention will be further described by way of examples and comparative examples in order to facilitate the understanding of the present invention, but the invention is not limited thereto.

(1) About the decomposition of azole caused by hydrogen peroxide

The components shown in Tables 1 and 2 were dissolved in ion-exchanged water to prepare etching liquids of Examples 1 to 13 and Comparative Examples 1 to 8. The hydrochloric acid shown in Tables 1 and 2 used a concentration of hydrogen chloride of 35% by weight.

On the other hand, a copper-clad laminate (a substrate for a printed circuit board) having a thickness of 12 μm copper foil is adhered to a glass epoxy substrate ("GEA-67N" manufactured by Hitachi Chemical Co., Ltd.), and the thickness is adhered thereto. 15μm dry film inhibitor (SUNFORT SPG-152) made by Asahi Kasei, forming a line width and spacing = 25μm / 25μm (line width of 25μm, line-to-line gap 25μm) Etch pattern.

Next, using the etching liquids of Examples 1 to 13 and Comparative Examples 1 to 8, spraying was carried out under the conditions of a spray pressure of 0.15 MPa at 40 ° C, and a copper foil not covered with the above-described corrosion inhibitor pattern was etched to form copper. After the wiring pattern, a 3 wt% aqueous sodium hydroxide solution was sprayed to remove the dry film inhibitor.

The obtained laminated board was cut, the cross-sectional shape of the formed copper wiring pattern (the shape of FIG. 1) was observed, and the difference between the width (W ₂ ) of the bottom of the copper wiring and the width (W ₁ ) of the top was measured (W). _{2 -} W ₁ ), and set it as the initial value in Table 1 and Table 2.

Further, unlike the above, the etching liquids of Comparative Examples 1 to 8 shown in Tables 1 to 13 and Table 2 shown in Table 1 were prepared, and then hydrogen peroxide water (hydrogen peroxide) was added to each etching liquid. Concentration: 35 wt%) 25 g/L, and the material obtained in this manner was allowed to stand at room temperature for 24 hours.

Thereafter, using the etching liquid, a copper wiring pattern was formed in the same manner as described above, and the difference (W ₂ -W ₁ ) between the width (W ₂ ) of the bottom of the copper wiring and the width (W ₁ ) of the top was measured. The values after hydrogen peroxide placement (after addition) were added and are shown in Tables 1 and 2. Further, the residual amount of the azole at this time was measured by liquid chromatography. Since the residual amount of 1H-tetrazole is difficult to measure by liquid chromatography, only the value of W ₂ -W ₁ is shown.

As shown in Tables 1 and 2, in each of the examples, the shape of the copper wiring was maintained in a good state even when hydrogen peroxide was added and left for 24 hours. I think this is because even after the addition of hydrogen peroxide, various azoles remain.

(2) Regarding the concentration change of azole in continuous use

Next, the change in the concentration of the azole when the etching solution was continuously used was measured.

The etching liquid of Comparative Example 2 shown in Example 2 and Table 2 shown in Table 1 was prepared. Further, the components shown below were dissolved in ion-exchanged water to prepare a replenishing liquid.

<Component of replenishing liquid>

Hydrochloric acid (concentration of hydrogen chloride: 35% by weight) 183 g / L 5-amino-1H-tetrazole 1.5 g / L 2-phenoxyethanol 1 g / L 2,4,6-tris(dimethylaminomethyl) Phenol 3g/L

After the etching liquids of the second embodiment and the second comparative example were placed in a 1 L spray tank, a copper plating plate was placed in each of the spray tanks, and the copper was etched while spraying at a temperature of 40 ° C and a spray pressure of 0.15 MPa. The cuprous copper concentration (the cuprous ion concentration) was measured every 20 seconds. At this time, if the cuprous concentration exceeds 0.65 g/L, 250 μL of hydrogen peroxide (concentration of hydrogen peroxide: 35 wt%) is added. The above-mentioned copper plating plate is made of a copper-clad laminate (substrate for a printed circuit board) having a thickness of 35 μm copper foil adhered to a glass epoxy substrate ("GEA-67N" manufactured by Hitachi Chemical Co., Ltd.). It was obtained by electrolytic copper plating of 18 μm (3.5 cm × 3.5 cm).

In the above spray treatment, one copper plate was allowed to stand for 2 minutes until the copper was completely dissolved, and the average dissolution rate of copper during this period was 0.29 g/L per minute. Further, with respect to the etching liquid of Example 2, 8 mL of the above-mentioned replenishing liquid was added per one copper plating plate. Next, the etching liquid of Example 2 and Comparative Example 2 was repeatedly subjected to the above operation until 62 sheets of copper plated sheets were processed. Next, in the etching liquids of Example 2 and Comparative Example 2 after the completion of the treatment, the residual amount of the azole was measured by liquid chromatography, and the residual ratio was calculated. The results are shown in the graph of Fig. 2.

As is clear from the graph of Fig. 2, the etching liquid of Example 2 was continuously etched while adding hydrogen peroxide, and the concentration of azole was maintained by adding a specific aromatic compound.

(industrial use)

According to the present invention, it is possible to provide an etching solution for copper and a method for forming a conductor pattern using the same, which can easily maintain the concentration of azole more than a certain amount even if it is used continuously or repeatedly, and can be used without changing the pattern. Etching is performed under the top shape. Further, the present invention is applicable not only to the formation of a conductor pattern on a printed circuit board but also to formation of various conductor patterns such as a conductor pattern on a glass substrate, a conductor pattern on a surface of a plastic substrate, and a conductor pattern on a semiconductor surface.

1‧‧‧Substrate

2‧‧‧Bronze wiring

3‧‧‧resist resin

Thickness (height) of T‧‧‧ copper wiring

W ₁ ‧‧‧ Wide width of the top of the copper wiring

Wide width of the bottom of W ₂ ‧‧‧ copper wiring

Fig. 1 is a schematic cross-sectional view showing an example of a wiring pattern obtained by using the etching liquid of the present invention.

Fig. 2 is a graph showing the change in azole concentration and the change in cuprous concentration in the continuous etching of the copper plated plate used in the etching liquids of Example 2 and Comparative Example 2.

1‧‧‧Substrate

2‧‧‧Bronze wiring

3‧‧‧resist resin

Thickness (height) of T‧‧‧ copper wiring

W ₁ ‧‧‧ Wide width of the top of the copper wiring

Wide width of the bottom of W ₂ ‧‧‧ copper wiring

Claims (13)

An etchant containing a source of copper ions, an acid, and a water, characterized by containing an azole and an aromatic compound having only a nitrogen atom as a hetero atom present in the ring, the aromatic compound being selected from the group consisting of phenols And at least one of aromatic amines. An etching solution according to claim 1, which further contains hydrogen peroxide. The etching solution of claim 1, wherein the aromatic compound has a concentration ranging from 0.01 to 20 g/L. The etching solution according to claim 1, wherein the copper ion source has a copper ion concentration of 14 to 155 g/L, the acid of 7 to 180 g/L, and the azole of 0.1 to 50 g/L. The etching solution of claim 1, wherein the azole is a tetrazole compound. An etching solution according to claim 1, wherein the aromatic compound is a phenol. The etching solution of claim 6, wherein the phenol is selected from the group consisting of phenolsulfonic acid or a salt thereof, cresolsulfonic acid or a salt thereof, salicylic acid or a salt thereof, lignosulfonic acid or a salt thereof, and 2 At least one of 4,6-tris(dimethylaminomethyl)phenol. The etching solution of claim 2, wherein the concentration of the hydrogen peroxide is in the range of 0.01 to 20 g/L. A method for forming a conductor pattern, characterized in that the application is used The etching solution according to any one of the items 1 to 8, wherein the portion of the copper layer on the electrically insulating material that is not covered by the resist is etched to form a conductor pattern. The method of forming a conductor pattern according to the ninth aspect of the invention, wherein the concentration of cuprous ions generated in the etching solution is 5 g/L or less while adding hydrogen peroxide to the etching solution. The method of forming a conductor pattern according to the ninth aspect of the invention, wherein the etching is performed while maintaining the concentration of the azole contained in the etching solution at 0.1 to 50 g/L. The method for forming a conductor pattern according to claim 9, wherein the replenishing liquid contains an acid, an azole, and an aromatic compound, and the azole has only a nitrogen atom as a hetero atom present in the ring. The atom, the aromatic compound is selected from at least one of a phenol and an aromatic amine. The method for forming a conductor pattern according to claim 12, wherein the replenishing liquid contains the acid in a concentration range of 7 to 360 g/L, the concentration of the azole is in the range of 0.1 to 50 g/L, and the aromatic compound The concentration range is 0.01~20g/L.