TW201811435A - Etching solution and etching concentrate for multilayer film, and etching method - Google Patents

Abstract

Provided is an etching solution which is for etching a multilayer film of copper and molybdenum and can be used in reduced quantities. In an etching solution using peroxide, the peroxide is decomposed by copper ions, and thus the etching solution is replenished in large quantities. The etching solution for a multilayer film is characterized by comprising a precipitation inhibitor which contains: hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, azoles, and an aluminum salt, wherein the precipitation inhibitor contains 0.4-5 mass% of ethylene glycol monobutyl ether as the hydrogen peroxide decomposition inhibitor, and the amine compound is N,N-diethyl-1,3-propanediamine. Even if the amount of copper ions increases, the peroxide decomposition rate can be suppressed, and the total amount of etching solution used can be reduced.

Description

   Etching solution, etching concentrate for multilayer film and etching method   

The present invention relates to an etching solution for a multilayer film, an etching concentrate, and an etching method for etching a multilayer film of copper and molybdenum used for wiring of a flat-panel display such as liquid crystal and organic EL.

A thin film transistor (TFT) of a flat panel display (FPD) such as a liquid crystal or an organic EL (Electro-Luminescence) uses aluminum as a wiring material. In recent years, large-screen and high-resolution FPDs have become widespread. Wiring materials used require materials with lower resistance than aluminum. Therefore, copper with lower resistance than aluminum has been used as a wiring material in recent years.

When copper is used as a wiring material, there are two problems of adhesion to a substrate and diffusion to a semiconductor substrate. That is, when it is used for gate wiring, even if a sputtering method generally considered to have a large impact energy on a base material, there may be insufficient adhesion between substrates such as glass. In addition, it is used at the source. During the drain wiring, the attached copper diffuses toward the underlying silicon, which causes a problem that the electrical design value of the semiconductor is changed.

In order to solve this problem, a multilayer structure is first adopted in which a molybdenum film is formed on a semiconductor substrate and a copper film is formed thereon.

FPD wiring is formed by wet etching of a multilayer film formed by a sputtering method. Since a large area can be formed in one breath, the steps can be shortened. Here, in wet etching of wiring, the following points are important.

(1) The machining accuracy is high and the same.

(2) The processed wiring cross-section is a taper of a predetermined angle.

(3) By including copper ions, the etching rate does not change (the etching bath has a long life).

(4) Precipitates rarely appear.

An etching solution that satisfies such a requirement is disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-209568).

Here, an etching solution for a multilayer film is disclosed, which comprises hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, azoles, and a precipitation inhibitor containing an aluminum salt.

This etching solution has an etching rate of copper (Cu) and molybdenum (Mo), a taper angle of a boundary region to be etched, an undercut of molybdenum (Mo), a residue of molybdenum (Mo), resistance to overetching, and precipitates The evaluation of the decomposition rate of hydrogen peroxide, hydrogen peroxide, etc., has the performance to meet the standards of current manufacturing.

On the other hand, the etchant of Patent Document 1 is based on the premise that a certain amount of etchant is discarded and a new etchant (referred to as a new liquid) is added as it is used.

Specifically, as shown in the example of Patent Document 1, a part of the etching solution is replaced with a new solution based on a Cu concentration of 2000 ppm. In such Patent Document 1, a part of the etching solution is replaced with a new solution because the etching rate is changed by the decomposition of hydrogen peroxide as the Cu concentration increases.

In the popularity of mobile terminals, the demand for flat-panel displays is increasing, and large-scale factories are also set up in manufacturing plants. In addition, there are plans to set up factories in the future. In such a large-scale factory, in order to reduce the cost of production lines, it is expected to reduce the amount of etching solution used. Because cost reductions in the manufacturing stage can reduce the price of the final product.

Here, the method for managing the etching solution will be briefly described. Molybdenum and copper are formed into a film, and a to-be-processed object (glass substrate, etc.) with a pattern drawn on a resist or the like is attached to an etching bath, processed one by one, and sent to a cleaning step. At this time, there is an etchant that is taken out of the etching tank together with the object to be processed. Therefore, whenever an object to be processed is removed from the etching bath, it is necessary to replenish the part of the etching solution that is taken out.

In addition, as the etching solution is used, the copper ion concentration in the etching solution becomes higher. In this system, copper ions reach a certain concentration because hydrogen peroxide in the etching solution is decomposed, and the etching solution needs to be supplemented to dilute the copper ion concentration. In addition, the etchant is replenished to supplement the decomposed hydrogen peroxide. In this way, an etching solution is added from these three viewpoints.

However, there have been previous proposals for a method for reducing the amount of copper etchant. Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-184076) and Patent Document 3 (Japanese Patent Application Laid-Open No. 2013-158707) recover copper from an acid in a copper etching solution, regenerate the etching solution, and reduce the etching solution. usage of.

In addition, Patent Document 4 (Japanese Patent Application Laid-Open No. 2000-054167) is suitable for oxidizing ferrous chloride and cuprous chloride to ferric chloride and copper chloride when the copper is etched with an iron chloride etching solution. In order to reduce the amount of use, the etching ability of the etchant is maintained constant.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2015-209568

Patent Document 2: Japanese Patent Application Laid-Open No. 2013-184076

Patent Document 3: Japanese Patent Application Publication No. 2013-158707

Patent Document 4: Japanese Patent Application Laid-Open No. 2000-054167

With the etchant of Patent Document 1, as the number of substrates processed increases, the concentration of Cu in the etchant increases, and decomposition of hydrogen peroxide proceeds. To maintain a certain etching ability, an etchant needs to be added. However, the addition of these three viewpoints is necessary for the etching solution carried by the object to be treated, dilution of copper ion concentration, and maintenance of hydrogen peroxide concentration, and a large amount of etching solution is required.

Patent Documents 2 and 3 use an acid in the etching solution, and recover the copper ions from the acid to regenerate the etching solution. Therefore, it cannot be applied to an etching solution using hydrogen peroxide.

In addition, Patent Document 4 maintains the etching ability of a certain etching solution by oxidizing copper ions in the etching solution, and cannot be applied to an etching solution using hydrogen peroxide. Because hydrogen peroxide is used in the etching solution, the hydrogen peroxide is decomposed, so the regeneration of the etching solution cannot be completed.

The present invention was conceived in order to solve the above-mentioned problems. By reducing the decomposition rate of hydrogen peroxide, the amount of etching solution added to maintain the concentration of hydrogen peroxide is greatly reduced, and the amount of etching solution used can be reduced.

Specifically, the etching solution for a multilayer film of the present invention includes: hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, an azole, and a precipitation inhibitor containing an aluminum salt. The hydrogen peroxide decomposition inhibitor contains ethylene glycol monobutyl ether in a ratio of 0.4% by mass to 5% by mass, and the amine compound is N, N-diethyl-1,3-propanediamine. Furthermore, ethylene glycol monobutyl ether is also referred to as "BG" in the future.

In addition, in order to solve the above problems, an etching solution for a multilayer film containing molybdenum and copper according to the present invention includes hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, an azole, and The aluminum salt precipitation inhibitor, the hydrogen peroxide decomposition inhibitor, contains ethylene glycol monobutyl ether in a ratio of 0.9% by mass to 5% by mass, and the amine compound is 1-amino-2-propanol.

With regard to the etchant of the present invention, compared with the etchant disclosed in Patent Document 1, the decomposition rate of hydrogen peroxide is increased at a Cu concentration of 2,000 ppm or more, and a very low decomposition rate of hydrogen peroxide is maintained even at 8,000 ppm.

Therefore, with regard to the etchant of the present invention, a longer additional interval for the etchant for supplementing the decrease in the concentration of hydrogen peroxide can be adopted. As a result, the effect which can reduce the usage-amount of an etchant is acquired.

1‧‧‧ substrate

2‧‧‧Cu layer

3‧‧‧Mo layer

4‧‧‧resist

5‧‧‧taper angle

6‧‧‧ inclined plane

10‧‧‧ inverse taper

FIG. 1 is a conceptual diagram showing a cross section of an etched wiring.

FIG. 2 is a graph showing a result of simulating a usage amount when a conventional etchant is used.

FIG. 3 is a graph showing the results of the amount used when the etching solution for a multilayer film of the present invention is used.

FIG. 4 is a graph showing the relationship between the content of BG and the decomposition rate of hydrogen peroxide.

Hereinafter, the etching solution for multilayer films of this invention is demonstrated. The following description is about an embodiment of the etching solution of the present invention, and the following embodiments and examples may be modified without departing from the spirit of the present invention. In the following description, when the numerical range is expressed as "A to B", it means "above A and below B". That is, a range that includes the numerical value A and is large, and includes a numerical value B and that is small.

The etching solution for a multilayer film of the present invention includes hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, an azole, and a precipitation inhibitor containing an aluminum salt. Each component is explained in detail below.

<Hydrogen peroxide>

In copper etching, copper is oxidized to copper oxide (CuO), and is dissolved by an acid (organic acid). In addition, the etching of molybdenum is oxidized to molybdenum oxide (MoO3) and dissolved in water. Hydrogen peroxide is used as an oxidant for copper oxide or molybdenum. Furthermore, hydrogen peroxide is synonymous with hydrogen peroxide. The hydrogen peroxide is preferably 4.0% to 5.8% by mass, more preferably 4.2% to 5.6% by mass, and most preferably 4.5% to 5.3% by mass.

<Organic acid>

The organic acid is responsible for adjusting the taper angle of the cross section of the etched wiring while etching the copper film. In addition, it is considered to have a function of inhibiting the decomposition of hydrogen peroxide to some extent. As the organic acid, an acidic organic acid is used. The etching solution for a multilayer film of the present invention may contain a neutral organic acid as a precipitation preventing agent described later.

Organic acids include, in addition to aliphatic carboxylic acids having 1 to 18 carbon atoms, aromatic carboxylic acids having 6 to 10 carbon atoms, amino acids having 1 to 10 carbon atoms, and the like.

Aliphatic carboxylic acids with 1 to 18 carbon atoms, such as formic acid, ester acid, propionic acid, lactic acid, glycolic acid, diglycolic acid, pyruvate, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, and succinic acid , Malic acid, maleic acid, fumaric acid, erythroic acid, glutaric acid, itaconic acid, adipic acid, caproic acid, citric acid, propanetricarboxylic acid, trans aconitic acid, heptanoic acid, caprylic acid, lauric acid , Tetradecanoic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, etc.

Examples of the aromatic carboxylic acid having 6 to 10 carbon atoms include benzoic acid, salicylic acid, mandelic acid, phthalic acid, isophthalic acid, and terephthalic acid.

Examples of the amino acids having 1 to 10 carbon atoms include amino formic acid, alanine, glycine, asparagine, aspartic acid, sarcosine, serine, glutamic acid, and glutamic acid. , 4-aminobutyric acid, imine dibutyric acid, arginine, leucine, isoleucine, nitrotriacetic acid, etc. are preferred.

Among the organic acids, glycolic acid, malonic acid, and lactic acid can be suitably used as the acidic organic acid. In particular, glycolic acid, malonic acid, and lactic acid can be used in combination of three types to obtain good characteristics.

Furthermore, the total amount of the glycolic acid based on the etching solution is preferably 1.3% to 3.3% by mass, more preferably 1.8% to 2.8% by mass, and most preferably 2.1% to 2.5% by mass.

In addition, malonic acid is preferably contained in an amount of 3.0% by mass to 5% by mass, more preferably 3.5% by mass to 4.5% by mass, and most preferably 3.8% by mass to 4.2% by mass.

In addition, lactic acid is preferably contained in an amount of 0.4% by mass to 1.6% by mass of the etching solution, more preferably 0.6% by mass to 1.4% by mass, and most preferably 0.8% by mass to 1.2% by mass.

In addition, the total amount of the acidic organic acid is preferably 4.7% to 9.9% by mass, more preferably 5.9% to 8.7% by mass, and most preferably 6.7% to 7.9% by mass.

<Amine compound>

The amine compound is responsible for pH adjustment of the etching solution. The amine compound is preferably a compound having 2 to 10 carbon atoms. More specific examples include ethylenediamine, trimethylenediamine, tetramethylenediamine, 1,2-propanediamine, 1,3-propanediamine, N, N-dimethyl-1,3- Propanediamine, N, N-diethyl-1,3-propanediamine, 1,3-diaminobutane, 2,3-diaminobutane, pentamethyleneamine, 2,4- Diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, N-methylethylenediamine, N, N-dimethylethyl Diamine, trimethylethylenediamine, N-ethylethylenediamine, N, N-diethylethylenediamine, triethylethylenediamine, 1,2,3-triaminopropane, hydrazine, Tris (2-aminoethyl) amine, tetra (aminomethyl) methane, diethylenetriamine, triethylenetetramine, tetraethylpentamine, heptaethylene octylamine, nonaethylene Polyamines such as decaamine, diazabicycloundecene; ethanolamine, N-methylethanolamine, N-methyldiethanolamine, N-ethylethanolamine, N-aminoethylethanolamine, N-propylethanolamine , N-butylethanolamine, diethanolamine, triethanolamine, 1-amino-2-propanol, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine, 2-aminoprop-1-ol, N-methyl-2-aminoprop-1-ol, N -Ethyl-2-aminoprop-1-ol, 1-aminoprop-3-ol, N-methyl-1-aminoprop-3-ol, N-ethyl-1-aminoprop- 3-alcohol, 1-aminobutan-2-ol, N-methyl-1-aminobutan-2-ol, N-ethyl-1-aminobutan-2-ol, 2-aminobutan- 1-alcohol, N-methyl-2-aminobut-1-ol, N-ethyl-2-aminobut-1-ol, 3-aminobut-1-ol, N-methyl-3 -Aminobut-1-ol, N-ethyl-3-aminobut-1-ol, 1-aminobut-4-ol, N-methyl-1-aminobut-4-ol, N -Ethyl-1-aminobut-4-ol, 1-amino-2-methylprop-2-ol, 2-amino-2-methylprop-1-ol, 1-aminopentyl- 4-alcohol, 2-amino-4-methylpent-1-ol, 2-aminohex-1-ol, 3-aminohept-4-ol, 1-aminooct-2-ol, 5 -Aminooct-4-ol, 1-amino-2,3-diol, 2-aminopropan-1,3-diol, tris (oxymethyl) aminomethane, 1,2-diamine Propyl-3-ol, 1,3-diaminoprop-2-ol, 2- (2-aminoethoxy) ethanol, 2- (2-aminoethylamino) ethanol, diethylene glycol Alkanolamines such as amines are preferred, and these can be used alone or in combination.

Among these, 1-amino-2-propanol (CAS code 78-96-6: hereinafter also referred to as "1A2P") or N, N-diethyl-1,3-propanediamine ( CAS number 104-78-9: hereinafter also referred to as "NNDPA." In addition, the amine compound is preferably 2.0% to 3.2% by mass for the entire amount of the etching solution, more preferably 2.2% to 3.0% by mass, and most preferably 2.4 to 2.8% by mass.

<Hydrogen peroxide decomposition inhibitor>

Regarding the etching solution for a multilayer film of the present invention, hydrogen peroxide is used as an oxidizing agent. Since hydrogen peroxide self-decomposes, a decomposition inhibitor that suppresses the decomposition is added. Hydrogen peroxide decomposition inhibitor, also known as hydrogen peroxide stabilizer (or "hydrogen peroxide stabilizer").

Especially in the case of the etching solution of the present invention, it is necessary to make the etching rate slightly change even when the Cu concentration reaches 8,000 ppm. In the present invention, ethylene glycol monobutyl ether (CAS number 111-76-2: hereinafter also referred to as "BG") can be favorably used.

Previously, hydrogen peroxide decomposition inhibitors have been favorably used in addition to urea-based hydrogen peroxide decomposition inhibitors such as phenyl urea, allyl urea, 1,3-dimethyl urea, and thiourea. Phenylacetamide, phenylethylene glycol, or lower alcohols such as 1-propanol and 2-propanol. However, it has been found that BG can exhibit a significant effect of suppressing the decomposition of hydrogen peroxide even at a high concentration of Cu to 8,000 ppm or more.

Furthermore, as will be described later, BG is effective by putting an etching solution in a certain amount or more, and it will saturate even if it is put in a large amount. Only the amount of other necessary components can be ensured, and even if a large amount is put in, the effect as an etching solution can be exhibited. However, adding more BG will increase costs. Considering the effect and price, it does not make sense to add more than 5% by mass of BG.

In addition, the content of BG varies depending on the coexisting amine compound. For example, when NNDPA, which can be used favorably as an azole, is used, BG, which is a hydrogen peroxide decomposition inhibitor, is preferably contained in an amount of 0.4% by mass to 5.0% by mass of the etching solution.

In addition, when 1A2P, which is an azole, can be used equally well, BG, which is a hydrogen peroxide decomposition inhibitor, is preferably contained in an amount of 0.9% by mass to 5.0% by mass of the etching solution.

In addition, phenyl urea, which was previously used as a hydrogen peroxide decomposition inhibitor, contains more than 0.2% by mass of the total amount of the etching solution, and the phenyl group will react with hydrogen peroxide to produce a reactant different from azoles and hydrogen peroxide Precipitates. However, such precipitates do not occur in BG. Therefore, it is also a good hydrogen peroxide decomposition inhibitor (a hydrogen peroxide stabilizer) from the viewpoint of suppressing the precipitates.

<Azoles>

The etching solution for a multilayer film of the present invention contains an azole that suppresses the etching rate of Cu and removes the residue of Mo. As the azoles, triazoles, tetrazoles, imidazoles, thiazoles, and the like can be suitably used. More specifically, it may be as follows.

As triazoles, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 3-amino-1H-triazole, and the like can be suitably used.

For tetrazoles, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, and the like can be suitably used. In addition, imidazoles can make good use of 1H-imidazole, 1H-benzimidazole, and the like. As the thiazoles, 1,3-thiazole, 4-methylthiazole, and the like can be suitably used.

Among these, tetrazoles have a high etching rate suppression effect, and especially 5-amino-1H-tetrazole (CAS number 4418-61-5: hereinafter also referred to as "5A1HT") is preferred.

The azoles preferably contain 0.04 mass% to 0.16 mass% of the total amount of the etching solution, more preferably 0.06 mass% to 0.14 mass%, and most preferably 0.08 mass% to 0.12 mass%.

<Precipitation preventing agent>

As described above, the etching solution containing hydrogen peroxide as the main component contains an organic acid to adjust the taper angle of the cross section of the wiring to be etched. However, organic acids are decomposed by peroxyhydroxide to generate oxalic acid. This oxalic acid forms copper oxalate with copper ions which are etched to exist in the etching solution, and becomes precipitates. Aluminum ions are more likely to form complexes with oxalic acid than copper and have higher solubility than copper oxalate.

Therefore, the etching solution of the present invention contains an aluminum salt in advance and does not become a precipitate (copper oxalate) even if copper ions are generated by etching. As the aluminum salt, inorganic salts such as aluminum sulfate, aluminum nitrate, and aluminum chloride, and organic salts such as aluminum lactate, aluminum acetate, and aluminum carbonate can be suitably used.

The precipitation preventing agent is preferably contained in an amount of 0.05% by mass to 0.7% by mass of the etching solution, more preferably 0.1% by mass to 0.5% by mass, and most preferably 0.2% by mass to 0.4% by mass.

<Copper ion>

An ordinary etching solution for a multilayer film is added with an etching solution for dilution to bring the Cu ion concentration to about 2,000 ppm to 4,000 ppm. Because the decomposition rate of hydrogen peroxide will become faster, and the concentration of hydrogen peroxide will decrease. However, since the etchant of the present invention can suppress the decomposition rate of hydrogen peroxide, it is not necessary to add an etchant for diluting Cu ions even if the Cu ion concentration becomes higher. More specifically, the Cu concentration of the etching solution is 8,000 ppm, and there is no need to add an etching solution for dilution.

<Other>

In the etching solution for a multilayer film of the present invention, in addition to these components, water and various additives commonly used in a range that does not inhibit the etching performance can be added. In the etching, since precision machining is a goal, it is preferable that foreign matter does not exist in water. Pure or ultrapure water is preferred. It is needless to say that the ranges of the content ratios of the respective components described above can be appropriately adjusted so that the total amount of the etching solution becomes 100% by mass.

<pH, temperature>

The etching solution for a multilayer film of the present invention has a pH of 2 to 6, and is preferably used in a range of pH 3 to 4.5. In addition, the etching solution can be used between 20 ° C and 40 ° C. It is more preferably 25 ° C to 35 ° C, and most preferably 30 ° C to 35 ° C.

<Save>

As the etching solution for a multilayer film of the present invention, hydrogen peroxide is used. Hydrogen peroxide will self-decompose. Therefore, the etching solution contains a hydrogen peroxide decomposition inhibitor. However, during storage, other liquids such as hydrogen peroxide (or hydrogen peroxide) can be stored separately. Alternatively, only raw materials other than hydrogen peroxide (or hydrogen peroxide water), water, and copper ions (referred to as "etching solution raw materials") may be stored together. In addition, liquid and powder may exist in the etchant raw material. That is, the etching solution for a multilayer film of the present invention can be completed by mixing an etching solution raw material with water and hydrogen peroxide (or hydrogen peroxide water).

Alternatively, a solution of the etchant material may be prepared by mixing the etchant material with water. The proportion of water in this solution may be smaller than the proportion of water in the etching solution shown in the examples described later. A solution of an etchant raw material and water made of an etchant raw material is called an "etching concentrate". Compared with the etching solution, the etching concentrated solution has a small amount of hydrogen peroxide, so the volume is small, so it is more convenient to store and transport. Therefore, the etching solution for a multilayer film of the present invention can be completed by mixing an etching solution, water, and hydrogen peroxide.

Here, the water of the etching concentrate may be any amount that can dissolve the raw material of the etching solution. That is, considering that the hydrogen peroxide is provided as an aqueous hydrogen peroxide solution, the etching solution for a multilayer film of the present invention can be completed by mixing three etching solutions, water, and hydrogen peroxide solution.

In addition, as long as the water is contained in the etching concentrated solution or hydrogen peroxide water, it can also be accomplished by mixing two of the etching concentrated solution and hydrogen peroxide water. In addition, in this specification, the ratio of each component of an etching concentrate is represented by the ratio with respect to the whole amount at the time of completion of an etching solution. Therefore, the total amount of each component of the etching concentrate is less than 100% by mass.

<Etching method>

Regarding the object of the etching solution for a multilayer film of the present invention, molybdenum is in the lower layer, and copper is the copper / molybdenum multilayer film in the upper layer. The thickness of the lower layer of molybdenum is thinner than that of the upper layer of copper. When the thickness of the lower layer is t0 and the thickness of the upper layer is t1, the range of t0 / t1 is in the range of 0.01 to 0.2. The range of t0 / t1 deviates from this range. If the Mo layer is too thick, residues of the Mo layer are liable to occur, and if it is too thin, the role as the bottom layer of the Cu layer cannot be exerted.

The etching solution for multilayer films of the present invention can be stored for a long time by storing hydrogen peroxide separately from the etching solution raw materials and water. Therefore, in actual use, such an etching solution is prepared. The method of blending is not particularly limited as long as the concentration of hydrogen peroxide finally reaches a predetermined concentration.

As an example, an etching concentrate for a certain amount of a water-mixed etching solution raw material is first prepared. The hydrogen peroxide is usually supplied as hydrogen peroxide water having a higher concentration than the hydrogen peroxide concentration of the etching solution for a multilayer film of the present invention. Here, the hydrogen peroxide water and the etching concentrate are prepared in a predetermined amount. This step may be referred to as a step of preparing an etching solution for a multilayer film.

When performing the etching, as described above, an etching solution is used under conditions of pH 2 to 6, 20 ° C to 40 ° C. Therefore, it is preferable that the etched substrate be preheated to this temperature. A method of bringing the substrate to be processed into contact with the etchant is not particularly limited. The shower solution can be used to spread the etching solution from above to the substrate to be processed, or the substrate to be processed can be immersed in the etching solution pool. This may be referred to as a step of contacting the substrate to be processed with an etching solution for a multilayer film.

The substrate to be processed refers to a substrate in a state where a molybdenum layer and a copper layer are laminated on a substrate such as glass, and a resist pattern for pattern formation is formed on the laminated film.

Next, simple simulation results are shown in FIG. 2 and FIG. 3 to show the effect of the etchant of the present invention. The simulation conditions are shown below. The total number of processed pieces (copper vapor-deposited on the glass substrate) was 3,000 pieces, and the film thickness of copper on each glass substrate was 300 nm. The capacity of the etching tank is 2,600L. The amount of etching solution taken out per substrate was 1L. Therefore, the replenishment amount of the etching solution is also increased by 1 L per one substrate.

In addition, the horizontal axis system of each graph of FIG. 2 and FIG. 3 shows the number of processing pieces (pieces) of a substrate, and a scale of 0 to 3,000 is provided. The 3,000-piece portion is indicated by a vertical arrow. In addition, each vertical axis system starts from zero, and the maximum scale is shown in the graph.

The hydrogen peroxide concentration of the etching solution is maintained between 5.3% by mass and 5.25% by mass. The hydrogen peroxide concentration of the etching solution added to increase the hydrogen peroxide concentration was 10% by mass.

The substrate processing time was set to 140 seconds per wafer. The initial value of the Cu concentration in the etching solution is from 2,000 ppm. The decomposition rate of hydrogen peroxide was set to 0.2 mass% / hr at a copper ion concentration of 8,000 ppm.

(A) to (f) of FIG. 2 show changes and the like when using the conventional etching solution (in the case of Patent Document 1). Cu concentration is maintained between 2,900 ppm and 3,500 ppm. The number of slices processed on the horizontal axis in the full chart. FIG. 2 (a) shows changes in the Cu concentration of the etching solution in the etching bath. The vertical axis is the copper ion concentration (ppm). The copper ion concentration starting from 2,000 ppm was about 3,500 ppm at the 400th processed object. To dilute the Cu ion concentration, an etchant is added.

In FIG. 2 (c), the vertical axis indicates the total amount (L) of the etchant added to the etching bath. The number of processed sheets was 400th, and 500L of etching solution was added. Referring to FIG. 2 (a) again, by adding this etching solution, the copper ion concentration drops to 2,900 ppm (see arrow A). After that, this state is repeated.

In FIG. 2 (b), the vertical axis represents changes in the concentration of hydrogen peroxide in the etching solution (described as "wt%". Synonymous with mass%.). The initial ratio of hydrogen peroxide was 5.3% by mass, and the hydrogen peroxide was decomposed by copper ions shown in FIG. 2 (a). In the treatment of about 100 tablets, the hydrogen peroxide concentration was 5.25 mass%. Therefore, in order to increase the hydrogen peroxide concentration, an etching solution containing 10% by mass of hydrogen peroxide is added (the other compositions are the same.).

FIG. 2 (d) is a graph showing a total amount of 10 mass% hydrogen peroxide etching solution added to adjust the hydrogen peroxide concentration. Total vertical axis (L). After processing 100 tablets, add 50L. Referring to FIG. 2 (b) again, by adding the etching solution containing 10% by mass of hydrogen peroxide, the hydrogen peroxide concentration in the etching bath is returned to 5.3% by mass again (see arrow B).

FIG. 2 (e) shows a change in the replenishment of the etching solution carried by the substrate. The vertical axis represents the additional amount (L). Here, a case where 1 L of etching solution is added per one sheet is shown.

Fig. 2 (f) shows the total amount of the etching solution added as described above. Total vertical axis (L), the vertical axis scale is engraved to 10,000L. According to the simulation, the total amount of the etchant added between the processing of 3,000 pieces requires 10,000 L or more.

FIG. 3 shows the situation of the etching solution of the present invention. (a) to (f) are diagrams corresponding to FIG. 2. Refer to Figure 3 (a). In the present invention, until the copper ion concentration in the etching solution reaches 8,000 ppm, no dilution is required. Therefore, the concentration of copper ions in the etching solution increases to the number of processed pieces of 3,000 pieces.

In addition, as the copper ion concentration in the etching solution increases, the copper contained in the etching solution taken away by the substrate also increases. Therefore, the copper ion concentration in the etching solution contained in the etching bath increases with the number of pieces processed Increase, the upward tendency is more moderate.

FIG. 3 (c) shows the amount of etching solution added to dilute the copper ion concentration. In the etching solution of the present invention, since the copper ion concentration reaches 8,000 ppm and no dilution is required, the added etching solution from this viewpoint is zero. When the hydrogen peroxide decomposition rate at this time was 8,000 ppm, the rate was 0.16 mass% / hr.

Figure 3 (b) shows the change in hydrogen peroxide concentration. With the increase of copper ion concentration, the decomposition rate of hydrogen peroxide will become faster. Therefore, as the number of processed pieces increases, the additional interval becomes shorter. Therefore, the total addition amount of the etchant containing 10% by mass of hydrogen peroxide (see FIG. 3 (d)) becomes larger than that in the case of FIG. 2. In FIG. 2 (d), although the maximum scale is 1,200L, in FIG. 3 (d), it is 2,000L. The supplementary portion of the substrate shown in FIG. 3 (e) is 1L per piece, which is the same as that in FIG. 2.

FIG. 3 (f) shows the total added amount (L) of the etchant when processing 3,000 pieces. The vertical scale is up to 4,000L. Therefore, according to the etching solution of the present invention, about 3,000 pieces are used, and about 5,000 L of the etching solution is used. This can be estimated to the extent of half of 10,000L shown in FIG. 2 (f).

In this way, the decomposition rate of hydrogen peroxide is suppressed, and even if the copper ion concentration becomes high, there is no need to dilute the etching solution, and the amount of the etching solution used can be greatly reduced.

Examples

<Explanation of various evaluation methods>

Regarding the etching solution for a multilayer film of the present invention, the etching rate (nm / min) of copper and molybdenum, the taper angle (°) of the cross section of the etched wiring, the undercut of the molybdenum layer, and the molybdenum layer remaining on the substrate ( Also referred to as "Mo residue".), Evaluation of over-etching resistance, presence of precipitates, and decomposition rate of hydrogen peroxide (mass% / 18hr).

The etching rate was measured as follows. First, a single-layer film was formed on a silicon wafer on which a 100-nm thermal oxide film was formed by sputtering to a thickness of 300 nm for copper and 150 nm for molybdenum. The copper film and the molybdenum film were brought into contact with an etching solution at 30 ° C. (which may be 35 ° C. according to the comparative example) for 20 seconds to 60 seconds.

The resistance value of the film before and after etching was measured using a 4-terminal 4-probe resistivity meter (manufactured by Mitsubishi Chemical Analytech: MCP-T610 type) in a constant current application mode. The change in film thickness was calculated from the change in the resistance value, and the etching rate was calculated.

In addition, if the etching rate of copper is 250 nm / min to 350 nm / min, it is determined as a circle (circle). In addition, if the etching rate of molybdenum is 60 nm / min to 120 nm / min, it is determined as a circle (circle). Otherwise, it is judged as a cross (×) outside the predetermined range.

Since the film thickness ratio of copper to molybdenum is about 10: 1, the etching rate of molybdenum seems to be too fast, but the molybdenum layer system constitutes the lower layer of the copper film, so if the etching rate is not made to the above-mentioned ratio, it cannot The appearance is etched at the same speed. Furthermore, "circle" means within the specification range, success or pass, and "fork" means outside the specification range, fail or fail. The following evaluations are the same.

The taper angle is measured as follows. First, molybdenum was formed into a thickness of 20 nm on a glass substrate by a sputtering method, and copper was further formed into a thickness of 300 nm on the glass substrate to prepare a Cu / Mo multilayer film sample. A resist having a wiring shape pattern formed on the copper film was used as a base material for the taper angle evaluation. That is, the substrate is composed of a substrate, a molybdenum film and a copper film thereon, and a resist layer on the copper film patterned into a wiring shape. This substrate is immersed in an etching solution, and can be etched just before the time of etching. After the etched sample was washed and dried, the wiring portion was cut and the cut surface was observed.

Observation of the cut surface was performed using SEM (Hitachi: SU8020 type) at an acceleration voltage of 1kV and 30,000 to 50,000 times. In addition, just the etching is the time from the beginning of the etching to the time when the film can let light through. The point at which the film can transmit light was confirmed visually.

The shape of the cut surface is shown in FIG. 1. As shown in FIG. 1 (a), an angle 5 formed by the substrate 1 and the etched inclined surface 6 is defined as a taper angle (°). A taper angle of 5 is determined as a circle (() as long as it is 30 to 60 °. Outside the range of this angle, it is determined to be a cross (×). In addition, in FIG. 1 (a), the Mo layer is denoted by symbol 3, the Cu layer is denoted by symbol 2, and the resist is denoted by symbol 4.

The undercut of the molybdenum layer is shown in FIG. 1 (b) as a symbol 10, and the state (inverse taper) between the molybdenum layer 3 and the substrate 1 is etched relatively quickly. The evaluation can be performed simultaneously with the evaluation of the taper angle 5. From the observation of 30,000 to 50,000 times of SEM, if no undercut of the molybdenum layer is found, it is judged as a circle (○), and if it is found, it is judged as a fork (×).

The Mo residue was observed with an optical microscope and SEM. When the residue was confirmed, it was judged to be a fork (×), and when it was not confirmed, it was judged to be a circle ((). In addition, the optical microscope is observed at a magnification of about 100 times in a bright field observation and a dark field observation. In addition, the SEM is observed at 30,000 to 50,000 times.

The so-called over-etching resistance (also referred to as "OE resistance") is the observation of the taper angle, the undercut of the molybdenum layer, and the Mo residue when the etching is performed at twice the etching time. All are judged by "circle" It is circle (○). As long as any one is evaluated as a "fork", it is judged as a fork (×).

The presence or absence of precipitates was determined by visually determining whether light blue precipitates were generated in the bottle after the etching solution was prepared, and the bottle was left at room temperature for a predetermined time (3 hours). When no precipitate was observed visually, it was judged to be a circle (○), and when it was visually confirmed, it was judged to be a cross (×).

The decomposition rate of hydrogen peroxide is based on the prepared etching solution, adding Cu ions and Mo ions to 8,000ppm and 800ppm, respectively. After a predetermined time (18hr (hour)) at 35 ° C, permanganic acid is used. As a titration reagent, potassium was measured with an automatic titration device (GT-200 manufactured by Mitsubishi Chemical Analytech). Then, the decomposition rate (mass% / hr) was calculated from the amount of change in the hydrogen peroxide concentration. As long as the decomposition rate of hydrogen peroxide is 0.16 mass% / hr or less, it is considered that there is no problem in the mass production scale. In addition, if a rough estimate is made by simulation, the amount of etchant used can also be reduced sufficiently.

(Example 1)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 90% by mass of BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventing agent, the raw material of the composition of the etching solution was formulated with 75.32% by mass of water to prepare an etching concentrated solution. In addition, the ratio of each component in an etching concentrate is represented by the ratio of the total amount when the etching solution is mixed with the hydrogen peroxide water mentioned later. The same applies to the following examples and comparative examples.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.16% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 1 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Example 2)

Will be 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 2.00% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventive agent, the raw material of the composition of the etching solution was formulated with 74.22% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 84.06% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 1 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Example 3)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of NNDPA

As an amine compound; 0.40% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventive agent, the raw material of the etching solution composed was prepared with 75.82% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the total amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.66% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 1 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Example 4)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of NNDPA

As an amine compound; 0.90% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventing agent, the raw material of the composition of the etching solution was formulated with 75.32% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.16% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 1 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Example 5)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of NNDPA

As an amine compound; 2.00% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventive agent, the raw material of the composition of the etching solution was formulated with 74.22% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 84.06% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 1 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative example 1)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.30% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

Used as a precipitation inhibitor; the raw material of the etching solution is composed with 75.92% by mass of water to prepare an etching concentrate.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.76% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative example 2)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.40% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

As a precipitation preventive agent, the raw material of the etching solution is composed with 75.82% by mass of water to prepare an etching concentrate.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.66% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative example 3)

Will consist of 1.90 mass% glycolic acid, 3.40 mass% malonic acid, 0.80 mass% lactic acid

As an acidic organic acid; 2.20% by mass of NNDPA

As an amine compound; 0.30% by mass BG

As hydrogen peroxide stabilizer; 0.08 mass% 5-amino-1H-tetrazole

As azoles, 0.26 mass% aluminum lactate

Used as a precipitation inhibitor; the raw material of the etching solution is composed with 75.92% by mass of water to prepare an etching concentrate.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.76% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative Example 4)

Will consist of 1.87% by mass of glycolic acid, 3.41% by mass of malonic acid, and 0.69% by mass of lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.10% by mass of phenylurea

As hydrogen peroxide stabilizer; 0.12% by mass of 5-amino-1H-tetrazole

As azoles, 0.28 mass% aluminum nitrate

Used as a precipitation inhibitor; the raw material of the etching solution is composed with 76.19% by mass of water to prepare an etching concentrate.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. Moreover, the total amount of water was 86.03 mass%. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative example 5)

Will consist of 1.87% by mass of glycolic acid, 3.41% by mass of malonic acid, and 0.69% by mass of lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.10% by mass of urea

As hydrogen peroxide stabilizer; 0.12% by mass of 5-amino-1H-tetrazole

As azoles, 0.22 mass% aluminum lactate

As a precipitation preventing agent, the raw material of the composition of the etching solution was formulated with 76.25% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 86.09% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative Example 6)

Will consist of 1.87% by mass of glycolic acid, 3.41% by mass of malonic acid, and 0.69% by mass of lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.10% by mass of phenylurea

As hydrogen peroxide stabilizer; 0.12% by mass of 5-amino-1H-tetrazole

As the azoles, 0.56 mass% beta alanine and 0.28 mass% aluminum nitrate

As a precipitation preventive agent, the raw material of the etching solution is composed with 75.63% by mass of water to prepare an etching concentrate.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of etching solution) was mixed with the etching concentrated solution to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.47% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

(Comparative Example 7)

Will consist of 1.87% by mass of glycolic acid, 3.41% by mass of malonic acid, and 0.69% by mass of lactic acid

As an acidic organic acid; 2.20% by mass of 1-amino-2-propanol

As an amine compound; 0.10% by mass of phenylurea

As hydrogen peroxide stabilizer; 0.12% by mass of 5-amino-1H-tetrazole

As the azoles, 0.56% by mass of β alanine and 0.22% by mass of aluminum lactate

As a precipitation preventing agent, the raw material of the etching solution composed was prepared with 75.69% by mass of water to prepare an etching concentrated solution.

15.14% by mass of 35% hydrogen peroxide water (5.3% by mass of hydrogen peroxide and 9.84% by mass of water for the entire amount of the etching solution) was mixed with the etching concentrate to prepare an etching solution having a hydrogen peroxide concentration of 5.3% by mass. The total amount of water was 85.53% by mass. Furthermore, copper lactate was added to adjust the copper ion concentration to 8,000 ppm. In addition, molybdenum powder was added to adjust the molybdenum concentration to 800 ppm. The liquid temperature was 35 ° C. Table 2 shows the concentration of each component in the entire etching solution and the results of each evaluation item.

Referring to Table 2, Comparative Examples 1, 2, and 3 each contained BG as a hydrogen peroxide stabilizer. However, in either case, the decomposition rate of hydrogen peroxide was higher than 0.16 mass%. FIG. 4 is a graph showing the decomposition rates of hydrogen peroxide in Comparative Examples 1, 2, and 3 and Examples 1 to 5. FIG. The content (mass%) of the horizontal axis BG and the rate of hydrogen peroxide decomposition (mass% / hr) of the vertical axis.

In the case where the black square system uses 1A2P as the amine compound, the case where the black circle system uses NNDPA as the amine compound. Furthermore, in Comparative Examples 1, 2, and 3, the symbols of small white circles were placed among the black squares and the black circles.

Referring to FIG. 4, in the case of 1A2P and the case of NNDPA, as the amount of BG of the hydrogen peroxide stabilizer increases, the rate of hydrogen peroxide decomposition decreases. In addition, the decomposition rate of hydrogen peroxide using NNDPA is lower than that of 1A2P.

Referring again to Table 2, Comparative Examples 4 to 7 are cases where the previously used phenyl urea was used as a hydrogen peroxide stabilizer. In Comparative Examples 4 to 7 (when 1A2P was used as the amine compound), the decomposition rate of hydrogen peroxide was fast, and even the slowest Comparative Example 7 was 0.219% by mass / hr.

Referring again to FIG. 4, the hydrogen peroxide decomposition rate in the case of Comparative Example 7 is indicated by a dotted line. As can be seen from FIG. 4, when 1A2P is used as the amine compound, BG as the hydrogen peroxide stabilizer needs to be 0.9% by mass or more. When NNDPA is used as the amine compound, BG as the hydrogen peroxide stabilizer may be contained in an amount of 0.4% by mass or more.

On the other hand, even if the addition of the hydrogen peroxide stabilizer is 2.0% by mass or more with respect to the entire amount of the etching solution, the effect (the reduction of the hydrogen peroxide decomposition rate) is almost saturated. In the examples, an example in which the content of BG is 2.0% by mass or more is omitted. Therefore, in the graph of FIG. 4, there are no plot points where the BG concentration is 2.0% by mass or more.

In summary, in the examples, it is shown that when the amine compound is NNDPA, BG is preferably 0.4% to 2.0% by mass, more preferably 0.9% to 2.0% by mass, and most preferably 2.0% by mass. When the amine compound is 1-amino-2-propanol, BG is preferably 0.9% by mass to 2.0% by mass, and more preferably 2.0% by mass.

On the other hand, as explained, it does not make sense to contain BG in excess of 5 mass%. Therefore, the range of BG can be described as follows. When the amine compound is NNDPA, BG is preferably 0.4% to 5.0% by mass, more preferably 0.9% to 5.0% by mass, and most preferably 2.0% to 5.0% by mass. When the amine compound is 1-amino-2-propanol, BG is preferably 0.9% by mass to 5.0% by mass, and more preferably 2.0% by mass to 5.0% by mass.

[Industrial profitability]

The etching solution of the present invention can be suitably used when etching a multilayer film of molybdenum and copper. In particular, even if the copper ion concentration becomes very high, the decomposition rate of the hydrogen peroxide water can be suppressed, so that a predetermined range of the etching rate can be maintained for a long period of time.

Claims (11)

    An etching solution for a multilayer film, comprising: hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, azoles, and a precipitation inhibitor containing an aluminum salt; the hydrogen peroxide decomposition inhibitor, Ethylene glycol monobutyl ether is contained in a ratio of 4% by mass to 5% by mass, and the amine compound is N, N-diethyl-1,3-propanediamine.         An etching solution for a multilayer film, comprising: hydrogen peroxide, an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, azoles, and a precipitation inhibitor containing an aluminum salt; the hydrogen peroxide decomposition inhibitor, Ethylene glycol monobutyl ether is contained in a ratio of 0.9% by mass to 5% by mass, and the amine compound is 1-amino-2-propanol.         The etching solution for a multilayer film according to item 1 or 2 of the scope of patent application, wherein the aluminum salt is aluminum lactate.         The etching solution for a multilayer film according to claim 1 or 2, wherein the acidic organic acid includes at least one of glycolic acid, malonic acid, and lactic acid.         The etching solution for a multilayer film according to item 1 or 2 of the scope of the patent application, wherein the azole-based 5-amino-1H-tetrazole is used.         The etching solution for a multilayer film according to item 1 or 2 of the scope of patent application, further including copper ion of 8,000 ppm or more.         An etching concentrate for a multilayer film, comprising: an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, an azole, a precipitation inhibitor containing an aluminum salt, and water, which will be used as the hydrogen peroxide decomposition inhibitor Ethylene glycol monobutyl ether is included in the total amount after final preparation as an etching solution in a ratio of 0.4% by mass to 5% by mass, and the amine compound is N, N-diethyl-1,3-propanediamine. amine.         An etching concentrated solution for a multilayer film, comprising: an acidic organic acid, an amine compound, a hydrogen peroxide decomposition inhibitor, an azole, a precipitation inhibitor containing an aluminum salt, and water, which will be used as the hydrogen peroxide decomposition inhibitor. Ethylene glycol monobutyl ether is contained in a total amount of 0.9% by mass or more and 5% by mass or less of the entire amount after the final preparation as an etching solution, and the amine compound is 1-amino-2-propanol.         An etching method for a multilayer film, comprising: an acidic organic acid; N, N-diethyl-1,3-propanediamine as an amine compound; azoles; an aluminum salt-containing precipitation preventing agent; Water, and ethylene glycol monobutyl ether as a hydrogen peroxide decomposition inhibitor, the total concentration of the etching solution after the final preparation as an etching solution, the etching concentrated solution contained in a ratio of 0.4% by mass to 5% by mass, and water and a solvent A step of preparing hydrogen oxide to prepare an etching solution for a multilayer film; and a step of bringing the etching solution for a multilayer film into contact with a substrate to be processed.         An etching method for a multilayer film, comprising: an acidic organic acid, 1-amino-2-propanol of an amine compound, azoles, a precipitation preventing agent including an aluminum salt, and water, which will be used as the above-mentioned transition agent. Ethylene glycol monobutyl ether, which is a hydrogen oxide decomposition inhibitor, is formulated with water and hydrogen peroxide to the total concentration of the etching solution after the final preparation, which is contained in a ratio of 0.9% by mass to 5% by mass. A step of an etching solution for a multilayer film; and a step of bringing the above-mentioned etching solution for a multilayer film into contact with a substrate to be processed.         The etching method for a multilayer film according to item 9 or 10 of the scope of application for a patent, wherein in the step of contacting the etching solution for the multilayer film with the substrate to be processed, the pH of the etching solution for the multilayer film is in the range of 2 to 6, It is carried out under the conditions of 20 ° C to 40 ° C.